X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation
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X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in...
Magnetic Vortex Core Reversal by Low-Field Excitations
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU .Magnetic Vortex Core
Magnetic Vortex Core Reversal by Low-Field Excitations
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU .Magnetic Vortex CoreMagnetic
Magnetic Vortex Core Reversal by Low-Field Excitations
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU .MagneticMagnetic Vortex Core
The universal criterion for switching a magnetic vortex core in soft magnetic nanodots
Lee, K.-S.; Kim, S.-K.; Yu, Y.-S.; Choi, Y.-S.; Guslienko, K. Y.; Jung, H.; Fischer, P.
2008-10-01T23:59:59.000Z
The universal criterion for ultrafast vortex core switching between core-up and -down vortex bi-states in soft magnetic nanodots was empirically investigated by micromagnetic simulations and combined with an analytical approach. Vortex-core switching occurs whenever the velocity of vortex core motion reaches a critical value, which is {nu}{sub c} = 330 {+-} 37 m/s for Permalloy, as estimated from numerical simulations. This critical velocity was found to be {nu}{sub c} = {eta}{sub c}{gamma} {radical}A{sub ex} with A{sub ex} the exchange stiffness, {gamma} the gyromagnetic ratio, and an estimated proportional constant {eta}{sub c} = 1.66 {+-} 0.18. This criterion does neither depend on driving force parameters nor on the dimension or geometry of the magnetic specimen. The phase diagrams for the vortex core switching criterion and its switching time with respect to both the strength and angular frequency of circular rotating magnetic fields were derived, which offer practical guidance for implementing vortex core switching into future solid state information storage devices.
Interaction between magnetic vortex cores in a pair of nonidentical nanodisks
Sinnecker, J. P.; Vigo-Cotrina, H.; Garcia, F.; Novais, E. R. P.; Guimarães, A. P., E-mail: apguima@cbpf.br [Centro Brasileiro de Pesquisas Físicas, 22290-180, Rio de Janeiro, Rio de Janeiro (Brazil)
2014-05-28T23:59:59.000Z
The coupling of two nonidentical magnetic nanodisks, i.e., with different vortex gyrotropic frequencies, is studied. From the analytical approach, the interactions between the nanodisks along x and y directions (the coupling integrals) were obtained as a function of distance. From the numerical solution of Thiele's equation, we derived the eigenfrequencies of the vortex cores as a function of distance. The motion of the two vortex cores and, consequently, the time dependence of the total magnetization M(t) were derived both using Thiele's equation and by micromagnetic simulation. From M(t), a recently developed method, the magnetic vortex echoes, analogous to the Nuclear Magnetic Resonance spin echoes, was used to compute the distance dependence of the magnetic coupling strength. The results of the two approaches differ by approximately 10%; using one single term, a dependence with distance found is broadly in agreement with studies employing other techniques.
Dunin-Borkowski, Rafal E.
transformations.7 Recent experimental reports confirm these predictions of domain wall movement8Quantitative determination of vortex core dimensions in head-to-head domain walls using off-dimensional characterization of vortex core spin structures, which is important for future magnetic data storage based
Magnetic Vortex Core Reversal by Low-Field Excitations
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU .Magnetic Vortex
Magnetic Vortex Core Reversal by Low-Field Excitations
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU .Magnetic VortexMagnetic
Magnetic Vortex Core Reversal by Low-Field Excitations
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love YouTokamak| NationalMagnetic Vortex
Raychaudhuri, Pratap
Role of the Vortex-Core Energy on the Berezinskii-Kosterlitz-Thouless Transition in Thin Films-Kosterlitz-Thouless (BKT) transition in thin films of NbN at various film thickness, by probing the effect of vortex played by the vortex-core energy in determining the characteristic signatures of the BKT physics, and we
Mineral Deformation at Earth's Core-Mantle Boundary
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your1 SECTION A. Revised:7, atMineral Deformation at Earth's
Mineral Deformation at Earth's Core-Mantle Boundary
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your1 SECTION A. Revised:7, atMineral Deformation at
Mineral Deformation at Earth's Core-Mantle Boundary
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your1 SECTION A. Revised:7, atMineral Deformation atMineral
X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengtheningWildfires may contribute more toConsensusX-RayX-Ray Imaging of the
X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengtheningWildfires may contribute more toConsensusX-RayX-Ray Imaging of
X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengtheningWildfires may contribute more toConsensusX-RayX-Ray Imaging ofX-Ray
X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsingWhat isJoin theanniversaryI 1 0 3 P 0 d dX-Ray Imaging
X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsingWhat isJoin theanniversaryI 1 0 3 P 0 d dX-Ray
X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsingWhat isJoin theanniversaryI 1 0 3 P 0 d dX-RayX-Ray
X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsingWhat isJoin theanniversaryI 1 0 3 P 0 d
X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsingWhat isJoin theanniversaryI 1 0 3 P 0 dX-Ray Imaging
Vortex pinning by inhomogeneities in type-II superconductors
Chapman, Jon
Vortex pinning by inhomogeneities in type-II superconductors S.J. Chapman #3;y G. Richardson zx of a curvilinear vortex in an inhomogeneous type-II superconducting material in the limit as the vortex core radius of the superconducting electrons acts as a pinning potential for the vortex, so that vortices will be attracted
Vortex Interactions and Barotropic Aspects of Concentric Eyewall Formation HUNG-CHI KUO
Schubert, Wayne H.
of a tropical cyclone core with nearby weaker vorticity of various spatial scales. This paper considers, separation distance, companion vortex size, and core vortex skirt parameter. A vorticity skirt on the core6 times as strong as the larger companion vortex. An additional requirement is that the separation
Vortex in a relativistic perfect isentropic fluid and Nambu Goto dynamics
B. Boisseau
1999-11-26T23:59:59.000Z
By a weak deformation of the cylindrical symmetry of the potential vortex in a relativistic perfect isentropic fluid, we study the possible dynamics of the central line of this vortex. In "stiff" material the Nanbu-Goto equations are obtained
Vortex rings impinging on permeable boundaries
Mujal-Colilles, Anna; Dalziel, Stuart B.; Bateman, Allen
2015-01-17T23:59:59.000Z
, and the existence of a rebound of the core parallel to the formation of a secondary 47 vortex with opposite sign [14]. 48 More recently, attention has turned to the possibility of resuspension due to a vortex ring 49 impacting a bed of particles (e.g. [1], [15...
Vortex methods and vortex statistics
Chorin, A.J.
1993-05-01T23:59:59.000Z
Vortex methods originated from the observation that in incompressible, inviscid, isentropic flow vorticity (or, more accurately, circulation) is a conserved quantity, as can be readily deduced from the absence of tangential stresses. Thus if the vorticity is known at time t = 0, one can deduce the flow at a later time by simply following it around. In this narrow context, a vortex method is a numerical method that makes use of this observation. Even more generally, the analysis of vortex methods leads, to problems that are closely related to problems in quantum physics and field theory, as well as in harmonic analysis. A broad enough definition of vortex methods ends up by encompassing much of science. Even the purely computational aspects of vortex methods encompass a range of ideas for which vorticity may not be the best unifying theme. The author restricts himself in these lectures to a special class of numerical vortex methods, those that are based on a Lagrangian transport of vorticity in hydrodynamics by smoothed particles (``blobs``) and those whose understanding contributes to the understanding of blob methods. Vortex methods for inviscid flow lead to systems of ordinary differential equations that can be readily clothed in Hamiltonian form, both in three and two space dimensions, and they can preserve exactly a number of invariants of the Euler equations, including topological invariants. Their viscous versions resemble Langevin equations. As a result, they provide a very useful cartoon of statistical hydrodynamics, i.e., of turbulence, one that can to some extent be analyzed analytically and more importantly, explored numerically, with important implications also for superfluids, superconductors, and even polymers. In the authors view, vortex ``blob`` methods provide the most promising path to the understanding of these phenomena.
Chorin, A.J. [California Univ., Berkeley, CA (United States). Dept. of Mathematics]|[Lawrence Berkeley Lab., CA (United States)
1993-06-01T23:59:59.000Z
Vortex methods originated from the observation that in incompressible inviscid flow vorticity (or, more accurately, circulation) is a conserved quantity, as can be readily deduced from the absence of tangential stresses. Thus, if the vorticity is known at time t=0, one can find the flow at a later time by simply following the vorticity. In this narrow context, a vortex method is a numerical method that follows vorticity. The author restricts himself in these lectures to a special class of numerical vortex methods, those that are based on a Lagrangian transport of vorticity in hydrodynamics by smoothed particles (blobs) and those whose analysis contributes to the understanding of blob methods. Blob methods started in the 1930`s.
Kleckner, Dustin; Irvine, William T M
2013-01-01T23:59:59.000Z
The idea that the knottedness (hydrodynamic Helicity) of a fluid flow is conserved has a long history in fluid mechanics. The quintessential example of a knotted flow is a knotted vortex filament, however, owing to experimental difficulties, it has not been possible until recently to directly generate knotted vortices in real fluids. Using 3D printed hydrofoils and high-speed laser scanning tomography, we generate vortex knots and links and measure their subsequent evolution. In both cases, we find that the vortices deform and stretch until a series of vortex reconnections occurs, eventually resulting several disjoint vortex rings. This article accompanies a fluid dynamics video entered into the Gallery of Fluid Motion at the 66th Annual Meeting of the APS Division of Fluid Dynamics.
Dissipative dynamics of a vortex state in a trapped Bose-condensed gas
P. O. Fedichev; G. V. Shlyapnikov
1999-06-15T23:59:59.000Z
We discuss dissipative dynamics of a vortex state in a trapped Bose-condensed gas at finite temperature and draw a scenario of decay of this state in a static trap. The interaction of the vortex with the thermal cloud transfers energy from the vortex to the cloud and induces the motion of the vortex core to the border of the condensate. Once the vortex reaches the border, it immediately decays through the creation of excitations. We calculate the characteristic life-time of a vortex state and address the question of how the dissipative dynamics of vortices can be studied experimentally.
Improved vortex reactor system
Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO)
1995-01-01T23:59:59.000Z
An improved vortex reactor system for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor.
Houck, Edward D. (Idaho Falls, ID)
1994-01-01T23:59:59.000Z
A fluid transfer system that combines a vortex diode with a jet ejector to transfer liquid from one tank to a second tank by a gas pressurization method having no moving mechanical parts in the fluid system. The vortex diode is a device that has a high resistance to flow in one direction and a low resistance to flow in the other.
Improved vortex reactor system
Diebold, J.P.; Scahill, J.W.
1995-05-09T23:59:59.000Z
An improved vortex reactor system is described for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor. 12 figs.
The Holographic Superconductor Vortex
Marc Montull; Alex Pomarol; Pedro J. Silva
2009-09-02T23:59:59.000Z
A gravity dual of a superconductor at finite temperature has been recently proposed. We present the vortex configuration of this model and study its properties. In particular, we calculate the free energy as a function of an external magnetic field, the magnetization and the superconducting density. We also find the two critical magnetic fields that define the region in which the vortex configurations are energetically favorable.
Under consideration for publication in J. Fluid Mech. 1 Mixing in a vortex breakdown flow
Paris-Sud XI, Université de
& Kohlman 1971; Hall 1972; Lowson & Riley 1995) where it creates a sudden drop of the lift and an increase the core of the vortex. Artificial tornadoes within a chimney have been proposed as a way of converting
Hierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier
Grier, David
15 1050 15 (b) (c) (d) (e) packed close- core vortex ring (d) (e)(b) (c) (a) (f) corona t [sec] Rg) tracking its radius of gyration Rg over time. spheres is surrounded by a diffuse circulating corona
Hierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier
Grier, David
15 10 5 0 15 (b) (c) (d) (e) packed close- core vortex ring (d) (e) (b) (c) (a) (f) corona t [sec] Rg corona that extends outward for tens of micrometers. Although these clusters somewhat resemble
B. Boisseau
1999-01-18T23:59:59.000Z
From a recent study of a stationary cylindrical solution for a relativistic two-constituent superfluid at low temperature limit, we propose to specify this solution under the form of a relativistic generalisation of a Rankine vortex (Potential vortex whose the core has a solid body rotation).Then we establish the dynamics of the central line of this vortex by supposing that the deviation from the cylindrical configuration is weak in the neighbourhood of the core of the vortex. In "stiff" material the Nambu-Goto equations are obtained.
Feasibility of a vortex transistor
Nevirkovets, I.P.; Rudenko, E.M.
1985-08-01T23:59:59.000Z
An experimental test is reported of the feasibility of developing a vortex transistor using tunnel junctions made from tin. (AIP)
Strings, vortex rings, and modes of instability
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gubser, Steven S.; Nayar, Revant; Parikh, Sarthak
2015-03-01T23:59:59.000Z
We treat string propagation and interaction in the presence of a background Neveu–Schwarz three-form field strength, suitable for describing vortex rings in a superfluid or low-viscosity normal fluid. A circular vortex ring exhibits instabilities which have been recognized for many years, but whose precise boundaries we determine for the first time analytically in the small core limit. Two circular vortices colliding head-on exhibit stronger instabilities which cause splitting into many small vortices at late times. We provide an approximate analytic treatment of these instabilities and show that the most unstable wavelength is parametrically larger than a dynamically generated length scalemore »which in many hydrodynamic systems is close to the cutoff. We also summarize how the string construction we discuss can be derived from the Gross–Pitaevskii Lagrangian, and also how it compares to the action for giant gravitons.« less
Klein, Avraham [The Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 (Israel); Aleiner, Igor L., E-mail: aleiner@phys.columbia.edu [Physics Department, Columbia University, New York, NY 10027 (United States); Agam, Oded [The Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 (Israel); Physics Department, Columbia University, New York, NY 10027 (United States)
2014-07-15T23:59:59.000Z
We analyze the motion of quantum vortices in a two-dimensional spinless superfluid within Popov’s hydrodynamic description. In the long healing length limit (where a large number of particles are inside the vortex core) the superfluid dynamics is determined by saddle points of Popov’s action, which, in particular, allows for weak solutions of the Gross–Pitaevskii equation. We solve the resulting equations of motion for a vortex moving with respect to the superfluid and find the reconstruction of the vortex core to be a non-analytic function of the force applied on the vortex. This response produces an anomalously large dipole moment of the vortex and, as a result, the spectrum associated with the vortex motion exhibits narrow resonances lying within the phonon part of the spectrum, contrary to traditional view.
Deformation processing of HTS wire
Bingert, J. [Los Alamos National Lab., NM (United States)
1994-07-29T23:59:59.000Z
Methods to understand, control, and optimize deformation processing of HTS wire are outlined. Topics discussed include: technical progress, deformation processing effects on HTS - core uniformity in composite tapes, effects of rolling on tapes, deformation process modeling, channel die powder compaction stress-strain data, microhardness versus rolling reduction, minimum bifurcation strain versus material state, roll gap geometries for large versus small rolls, interactions, hydrostatic extrusion, and tensile properties.
Vortex-Based Aero- and Hydrodynamic Estimation
Hemati, Maziar Sam
2013-01-01T23:59:59.000Z
2001. [Kra91] R. Krasny. “Vortex Sheet Computations: Roll-NK94] M. Nitsche and R. Krasny. “A Numerical Study of Vortex
Önder, Asim; Meyers, Johan, E-mail: johan.meyers@mech.kuleuven.be [Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300A, B3001 Leuven (Belgium)
2014-07-15T23:59:59.000Z
We study the near field of a zero-net-mass-flux (ZNMF) actuated round jet using direct numerical simulations. The Reynolds number of the jet Re{sub D} = 2000 and three ZNMF actuators are used, evenly distributed over a circle, and directed towards the main jet. The actuators are triggered in phase, and have a relatively low momentum coefficient of C{sub ?} = 0.0049 each. We study four different control frequencies with Strouhal numbers ranging from St{sub D} = 0.165 to St{sub D} = 1.32; next to that, also two uncontrolled baseline cases are included in the study. We find that this type of ZNMF actuation leads to strong deformations of the near-field jet region that are very similar to those observed for non-circular jets. At the end of the jet's potential core (x/D = 5), the jet-column cross section is deformed into a hexagram-like geometry that results from strong modifications of the vortex structures. Two mechanisms lead to these modifications, i.e., (i) self-deformation of the jet's primary vortex rings started by distortions in their azimuthal curvature by the actuation, and (ii) production of side jets by the development and subsequent detachment of secondary streamwise vortex pairs. Further downstream (x/D = 10), the jet transforms into a triangular pattern, as the sharp corner regions of the hexagram entrain fluid and spread. We further investigate the global characteristics of the actuated jets. In particular when using the jet preferred frequency, i.e., St{sub D} = 0.33, parameters such as entrainment, centerline decay rate, and mean turbulent kinetic energy are significantly increased. Furthermore, high frequency actuation, i.e., St{sub D} = 1.32, is found to suppress the mechanisms leading to large scale structure growth and turbulent kinetic energy production. The simulations further include a passive scalar equation, and passive scalar mixing is also quantified and visualized.
Evolution of an initially columnar vortex terminating normal to a no-slip wall
Lopez, John M.
Èdewadt-type spatially oscillatory boundary layer within the core region and a potential-like vortex boundary layer at large radii. The toroidal structure results from the interaction between these two boundary layers's theo- retical study only applied to the boundary layer formed away from the core, as have most other
VORTEX BREAKDOWN INCIPIENCE: THEORETICAL CONSIDERATIONS
Erlebacher, Gordon
dimensional boundary layer (Hall 2;3 , Mager 4 ); (ii) vortex breakdown is a consequence of hydrodynamic instabilityVORTEX BREAKDOWN INCIPIENCE: THEORETICAL CONSIDERATIONS S. A. Berger Department of Mechanical in Science and Engineering NASA Langley Research Center Hampton, VA 236810001 ABSTRACT The sensitivity
Variable residence time vortex combustor
Melconian, Jerry O. (76 Beaver Rd., Reading, MA 01867)
1987-01-01T23:59:59.000Z
A variable residence time vortex combustor including a primary combustion chamber for containing a combustion vortex, and a plurality of louvres peripherally disposed about the primary combustion chamber and longitudinally distributed along its primary axis. The louvres are inclined to impel air about the primary combustion chamber to cool its interior surfaces and to impel air inwardly to assist in driving the combustion vortex in a first rotational direction and to feed combustion in the primary combustion chamber. The vortex combustor also includes a second combustion chamber having a secondary zone and a narrowed waist region in the primary combustion chamber interconnecting the output of the primary combustion chamber with the secondary zone for passing only lower density particles and trapping higher density particles in the combustion vortex in the primary combustion chamber for substantial combustion.
All-optical discrete vortex switch
Desyatnikov, Anton S. [Nonlinear Physics Center, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia); Dennis, Mark R. [H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Ferrando, Albert [Interdisciplinary Modeling Group, InterTech and Departament d'Optica, Universitat de Valencia, E-46100 Burjassot (Spain)
2011-06-15T23:59:59.000Z
We introduce discrete vortex solitons and vortex breathers in circular arrays of nonlinear waveguides. The simplest vortex breather in a four-waveguide coupler is a nonlinear dynamic state changing its topological charge between +1 and -1 periodically during propagation. We find the stability domain for this solution and suggest an all-optical vortex switching scheme.
Vortex Ring Interaction with a Particle Layer: Implications for Sediment Transport
Dalziel, Stuart
resuspension has been studied much less. This is an important mechanism, however, as it represents an integral conducted to study particle resuspension by vortex rings colliding with a particle bed. The dynamics at the resuspension onset are investigated, showing that the deformable particle bed resembles a free slip boundary
Gravity waves from vortex dipoles and jets
Wang, Shuguang
2009-05-15T23:59:59.000Z
The dissertation first investigates gravity wave generation and propagation from jets within idealized vortex dipoles using a nonhydrostatic mesoscale model. Several initially balanced and localized jets induced by vortex dipoles are examined here...
PLASTIC DEFORMATIONPLASTIC DEFORMATION Modes of Deformation
Subramaniam, Anandh
PLASTIC DEFORMATIONPLASTIC DEFORMATION Modes of Deformation The Uniaxial Tension Test Mechanisms underlying Plastic Deformation Strengthening mechanisms Mechanical Metallurgy George E Dieter McClick here to know about all the mechanisms by which materials fail #12;Slip (Dislocation motion) Plastic
Energy Spectrum of Vortex Tangle
Tsunehiko Araki; Makoto Tsubota; Sergey K. Nemirovskii
2001-06-29T23:59:59.000Z
The energy spectrum of superfluid turbulence in the absence of the normal fluid is studied numerically. In order to discuss the statistical properties, we calculated the energy spectra of the 3D velocity field induced by dilute and dense vortex tangles respectively, whose dynamics is calculated by the Biot-Savart law. In the case of a dense tangle, the slope of the energy spectrum is changed at $k=2\\pi/l$, where $l$ is the intervortex spacing. For $k>2\\pi/l$, the energy spectrum has $k^{-1}$ behavior in the same manner as the dilute vortex tangle, while otherwise the slope of the energy spectrum deviates from $k^{-1}$ behavior. We compare the behavior for $k<2\\pi/l$ with the Kolmogorov law.
Divergence of optical vortex beams
Reddy, Salla Gangi; Prabhakar, Shashi; Anwar, Ali; Banerji, J; Singh, R P
2015-01-01T23:59:59.000Z
We show, both theoretically and experimentally, that the propagation of optical vortices in free space can be analysed by using the width ($w(z)$) of the host Gaussian beam and the inner and outer radii of the vortex beam at the source plane ($z=0$) as defined in \\textit{Optics Letters \\textbf{39,} 4364-4367 (2014)}. We also studied the divergence of vortex beams, considered as the rate of change of inner or outer radius with the propagation distance, and found that it varies with the order in the same way as that of the inner and outer radii at zero propagation distance. These results may be useful in designing optical fibers for orbital angular momentum modes that play a crucial role in quantum communication.
Magnetic Vortex Core Reversal by Low-Field Excitations
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thought to be necessary to accomplish this. At the ALS, a team of researchers from Germany, Belgium, and the U.S. has used time-resolved scanning transmission x-ray microscopy...
Magnetic Vortex Core Reversal by Low-Field Excitations
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU .Magnetic
Magnetic Vortex Core Reversal by Low-Field Excitations
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Computing Vortex Sheet Motion Robert Krasny
Krasny, Robert
Computing Vortex Sheet Motion Robert Krasny Department of Mathematics, University of Michigan, Ann;1574 Robert Krasny with respect to the time variable and obtained results consistent with Moore
Superconducting vortex pinning with artificially prepared nanostructures
Rosen, Yaniv Jacob
K. Schuller, “Enhanced superconducting vortex pinning withat T/Tc = 0.99 of a superconducting Nb thin film on aof the triangles. The superconducting critical temperature
aircraft vortex spacing: Topics by E-print Network
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calculations and find that nontopological vortex solutions exist as well as Q-ball type solutions, but topological vortex solutions are not admitted. Inyong Cho; Youngone...
Vortex Hydro Energy Develops Transformational Technology to Harness...
Vortex Hydro Energy Develops Transformational Technology to Harness Energy from Water Currents Vortex Hydro Energy Develops Transformational Technology to Harness Energy from Water...
Light propagation around a relativistic vortex flow of dielectric medium
B. Linet
2000-11-06T23:59:59.000Z
We determine the path of the light around a dielectric vortex described by the relativistic vortex flow of a perfect fluid.
advanced vortex element: Topics by E-print Network
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method with mesh adaptivity for computing vortex states in fastrotating BoseEinstein condensates Computer Technologies and Information Sciences Websites Summary: ) vortices, vortex...
accelerated vortex ring: Topics by E-print Network
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rings and systems for controlled studies of vortex interactions in Bose-Einstein condensates HEP - Theory (arXiv) Summary: We study controlled methods of preparing vortex...
The London theory of the crossing-vortex lattice in highly anisotropic layered superconductors
S. E. Savel'ev; J. Mirkovic; K. Kadowaki
2001-05-18T23:59:59.000Z
A novel description of Josephson vortices (JVs) crossed by the pancake vortices (PVs) is proposed on the basis of the anisotropic London theory. The field distribution of a JV and its energy have been calculated for both dense ($a\\lambda_J$) PV lattices with distance $a$ between PVs, and the nonlinear JV core size $\\lambda_J$. It is shown that the ``shifted'' PV lattice (PVs displaced mainly along JVs in the crossing vortex lattice structure), formed in high out-of-plane magnetic fields transforms into the PV lattice ``trapped'' by the JV sublattice at a certain field, lower than $\\Phi_0/\\gamma^2s^2$, where $\\Phi_0$ is the flux quantum, $\\gamma$ is the anisotropy parameter and $s$ is the distance between CuO$_2$ planes. With further decreasing $B_z$, the free energy of the crossing vortex lattice structure (PV and JV sublattices coexist separately) can exceed the free energy of the tilted lattice (common PV-JV vortex structure) in the case of $\\gamma s<\\lambda_{ab}$ with the in-plane penetration depth $\\lambda_{ab}$ if the low ($B_x<\\gamma\\Phi_0/\\lambda_{ab}^2$) or high ($B_x\\gtrsim \\Phi_0/\\gamma s^2$) in-plane magnetic field is applied. It means that the crossing vortex structure is realized in the intermediate field orientations, while the tilted vortex lattice can exist if the magnetic field is aligned near the $c$-axis and the $ab$-plane as well. In the intermediate in-plane fields $\\gamma\\Phi_0/\\lambda_{ab}^2\\lesssim B_x \\lesssim \\Phi_0/\\gamma s^2$, the crossing vortex structure with the ``trapped'' PV sublattice seems to settle in until the lock-in transition occurs since this structure has the lower energy with respect to the tilted vortex structure in the magnetic field ${\\vec H}$ oriented near the $ab$-plane.
Vortex dynamics in 4 Banavara N. Shashikanth
Shashikanth, Banavara N.
Vortex dynamics in 4 Banavara N. Shashikanth Citation: J. Math. Phys. 53, 013103 (2012); doi: 10 OF MATHEMATICAL PHYSICS 53, 013103 (2012) Vortex dynamics in R4 Banavara N. Shashikantha) Mechanical and Aerospace dynamics of Euler's equations for a constant density fluid flow in R4 is studied. Most of the paper focuses
An investigation of the vortex method
Pryor, D.W. Jr.
1994-05-01T23:59:59.000Z
The vortex method is a numerical scheme for solving the vorticity transport equation. Chorin introduced modern vortex methods. The vortex method is a Lagrangian, grid free method which has less intrinsic diffusion than many grid schemes. It is adaptive in the sense that elements are needed only where the vorticity is non-zero. Our description of vortex methods begins with the point vortex method of Rosenhead for two dimensional inviscid flow, and builds upon it to eventually cover the case of three dimensional slightly viscous flow with boundaries. This section gives an introduction to the fundamentals of the vortex method. This is done in order to give a basic impression of the previous work and its line of development, as well as develop some notation and concepts which will be used later. The purpose here is not to give a full review of vortex methods or the contributions made by all the researchers in the field. Please refer to the excellent review papers in Sethian and Gustafson, chapters 1 Sethian, 2 Hald, 3 Sethian, 8 Chorin provide a solid introduction to vortex methods, including convergence theory, application in two dimensions and connection to statistical mechanics and polymers. Much of the information in this review is taken from those chapters, Chorin and Marsden and Batchelor, the chapters are also useful for their extensive bibliographies.
Ergoregion instability: The hydrodynamic vortex
Leandro A. Oliveira; Vitor Cardoso; Luís C. B. Crispino
2014-05-16T23:59:59.000Z
Four-dimensional, asymptotically flat spacetimes with an ergoregion but no horizon have been shown to be linearly unstable against a superradiant-triggered mechanism. This result has wide implications in the search for astrophysically viable alternatives to black holes, but also in the understanding of black holes and Hawking evaporation. Here we investigate this instability in detail for a particular setup which can be realized in the laboratory: the {\\it hydrodynamic vortex}, an effective geometry for sound waves, with ergoregion and without an event horizon.
V. E. Shapiro
2011-09-22T23:59:59.000Z
This work formulates and gives grounds for general principles and theorems that question the energy function doctrine and its quantum version as a genuine law of nature without borders of adequacy. The emphasis is on the domain where the energy of systems is conserved -- I argue that only in its tiny part the energy is in the kinetic, potential and thermal forms describable by a generalized thermodynamic potential, whereas otherwise the conserved energy constitutes a whole linked to vortex forces, and can be a factor of things like persistent currents and dark matter.
Vortex Energy | Open Energy Information
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Hierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier
Grier, David
often, the dense ring of 30 25 20 15 10 5 0 15 (b) (c) (d) (e) packed close- core vortex ring (d) (e) (b) (c) (a) (f) corona t [sec] Rg (t) [µm] +V h H 20 µm glass slide cluster electrode R g 20 µm FIG. 1 is surrounded by a di#11;use circulating corona that extends outward for tens of micrometers. Although
Spatiotemporal characterization of ultrashort optical vortex pulses
Miranda, Miguel; Rudawski, Piotr; Guo, Chen; Harth, Anne; L'Huillier, Anne; Arnold, Cord L
2015-01-01T23:59:59.000Z
Generation of few-cycle optical vortex pulses is challenging due to the large spectral bandwidths, as most vortex generation techniques are designed for monochromatic light. In this work, we use a spiral phase plate to generate few-cycle optical vortices from an ultrafast titanium:sapphire oscillator, and characterize them in the spatiotemporal domain using a recently introduced technique based on spatially resolved Fourier transform spectrometry. The performance of this simple approach to the generation of optical vortices is analyzed from a wavelength dependent perspective, as well as in the spatiotemporal domain, allowing us to completely characterize ultrashort vortex pulses in space, frequency, and time.
Jeong-Yup Lee; Robert V. Moody
2009-10-23T23:59:59.000Z
A linear deformation of a Meyer set $M$ in $\\RR^d$ is the image of $M$ under a group homomorphism of the group $[M]$ generated by $M$ into $\\RR^d$. We provide a necessary and sufficient condition for such a deformation to be a Meyer set. In the case that the deformation is a Meyer set and the deformation is injective, the deformation is pure point diffractive if the orginal set $M$ is pure point diffractive.
Josephson vortex lattice in layered superconductors
Koshelev, A. E., E-mail: koshelev@anl.gov [Argonne National Laboratory, Materials Science Division (United States); Dodgson, M. J. W. [Cavendish Laboratory, Theory of Condensed Matter Group (United Kingdom)] [Cavendish Laboratory, Theory of Condensed Matter Group (United Kingdom)
2013-09-15T23:59:59.000Z
Many superconducting materials are composed of weakly coupled conducting layers. Such a layered structure has a very strong influence on the properties of vortex matter in a magnetic field. This review focuses on the properties of the Josephson vortex lattice generated by the magnetic field applied in the direction of the layers. The theoretical description is based on the Lawrence-Doniach model in the London limit, which takes only the phase degree of freedom of the superconducting order parameter into account. In spite of its simplicity, this model leads to an amazingly rich set of phenomena. We review in detail the structure of an isolated vortex line and various properties of the vortex lattice, in both dilute and dense limits. In particular, we extensively discuss the influence of the layered structure and thermal fluctuations on the selection of lattice configurations at different magnetic fields.
The multiple vortex nature of tropical cyclogenesis
Sippel, Jason Allen
2005-02-17T23:59:59.000Z
cells and vortices are the respective source of PV production and building blocks for the meso-?-scale vortices. Finally, this thesis discusses issues related to the multiple vortex nature of tropical cyclone formation. For instance, the tracking...
Direct Imaging of Antiferromagnetic Vortex States
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H.W. Zhao, J. Bokor, and Z.Q. Qiu, "Direct observation of imprinted antiferromagnetic vortex states in CoOFeAg(001) discs," Nat. Phys. 7, 303 (2011). ALS Science Highlight 235...
Direct Imaging of Antiferromagnetic Vortex States
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and Z.Q. Qiu, "Direct observation of imprinted antiferromagnetic vortex states in CoOFeAg(001) discs," Nat. Phys. 7, 303 (2011). ALS Science Highlight 235 ALSNews Vol. 324...
Phases of Atom-Molecule Vortex Matter
Woo, S. J.; Bigelow, N. P. [Department of Physics and Astronomy, University of Rochester, Rochester, New York (United States); Park, Q-Han [Department of Physics, Korea University, Seoul (Korea, Republic of)
2008-03-28T23:59:59.000Z
We study ground state vortex configurations in a rotating atom-molecule Bose-Einstein condensate. It is found that the coherent coupling between the atomic and molecular condensates can render a pairing of atomic and molecular vortices into a composite structure that resembles a carbon dioxide molecule. Structural phase transitions of vortex lattices are also explored through different physical parameters including the rotational frequency of the system.
Reconnection of vortex filaments and Kolmogorov spectrum
Sergey K. Nemirovskii
2014-04-19T23:59:59.000Z
The energy spectrum of the 3D velocity field, induced by collapsing vortex filaments is studied. One of the aims of this work is to clarify the appearance of the Kolmogorov type energy spectrum $E(k)\\varpropto k^{-5/3}$, observed in many numerical works on discrete vortex tubes (quantized vortex filaments in quantum fluids). Usually, explaining classical turbulent properties of quantum turbulence, the model of vortex bundles, is used. This model is necessary to mimic the vortex stretching, which is responsible for the energy transfer in classical turbulence. In our consideration we do not appeal to the possible "bundle arrangement" but explore alternative idea that the turbulent spectra appear from singular solution, which describe the collapsing line at moments of reconnection. One more aim is related to an important and intensively discussed topic - a role of hydrodynamic collapse in the formation of turbulent spectra. We demonstrated that the specific vortex filament configuration generated the spectrum $E(k)$ close to the Kolmogorov dependence and discussed the reason for this as well as the reason for deviation. We also discuss the obtained results from point of view of the both classical and quantum turbulence.
Halos in a deformed relativistic Hartree-Bogoliubov theory in continuum
Li Lulu; Meng Jie; Ring, P.; Zhao Enguang; Zhou Shangui [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China) and Department of Physics, University of Stellenbosch, Stellenbosch (South Africa); Physikdepartment, Technische Universitaet Muenchen, 85748 Garching (Germany) and State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China) and Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China)
2012-10-20T23:59:59.000Z
In this contribution we present some recent results about neutron halos in deformed nuclei. A deformed relativistic Hartree-Bogoliubov theory in continuumhas been developed and the halo phenomenon in deformed weakly bound nuclei is investigated. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation of the core and the particles in the halo. Magnesium and neon isotopes are studied and detailed results are presented for the deformed neutron-rich and weakly bound nuclei {sup 42}Mg. The core of this nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the existence of halos in deformed nuclei and for the occurrence of this decoupling effect are discussed.
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cores per node for handling system services, and thus reduce the effects of timing jitter due to interruptions from the operating system at the expense of (possibly) requiring...
Vortex Hydro Energy (TRL 5 6 System) - Advanced Integration of...
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Vortex Hydro Energy (TRL 5 6 System) - Advanced Integration of Power Take-Off in VIVACE Vortex Hydro Energy (TRL 5 6 System) - Advanced Integration of Power Take-Off in VIVACE...
C. Peralta; A. Melatos; M. Giacobello; A. Ooi
2006-07-08T23:59:59.000Z
We investigate the global transition from a turbulent state of superfluid vorticity to a laminar state, and vice versa, in the outer core of a neutron star. By solving numerically the hydrodynamic Hall-Vinen-Bekarevich-Khalatnikov equations for a rotating superfluid in a differentially rotating spherical shell, we find that the meridional counterflow driven by Ekman pumping exceeds the Donnelly-Glaberson threshold throughout most of the outer core, exciting unstable Kelvin waves which disrupt the rectilinear vortex array, creating a vortex tangle. In the turbulent state, the torque exerted on the crust oscillates, and the crust-core coupling is weaker than in the laminar state. This leads to a new scenario for the rotational glitches observed in radio pulsars: a vortex tangle is sustained in the differentially rotating outer core by the meridional counterflow, a sudden spin-up event brings the crust and core into corotation, the vortex tangle relaxes back to a rectilinear vortex array, then the crust spins down electromagnetically until enough meridional counterflow builds up to reform a vortex tangle. The turbulent-laminar transition can occur uniformly or in patches; the associated time-scales are estimated from vortex filament theory. We calculate numerically the global structure of the flow with and without an inviscid superfluid component, for Hall-Vinen and Gorter-Mellink forms of the mutual friction. We also calculate the post-glitch evolution of the angular velocity of the crust and its time derivative, and compare the results with radio pulse timing data, predicting a correlation between glitch activity and Reynolds number.
Fractal powers in Serrin's swirling vortex solutions
Pavel B?lík; Douglas P. Dokken; Kurt Scholz; Mikhail M. Shvartsman
2014-04-28T23:59:59.000Z
We consider a modification of the fluid flow model for a tornado-like swirling vortex developed by J. Serrin, where velocity decreases as the reciprocal of the distance from the vortex axis. Recent studies, based on radar data of selected severe weather events, indicate that the angular momentum in a tornado may not be constant with the radius, and thus suggest a different scaling of the velocity/radial distance dependence. Motivated by this suggestion, we consider Serrin's approach with the assumption that the velocity decreases as the reciprocal of the distance from the vortex axis to the power $b$ with a general $b>0$. This leads to a boundary-value problem for a system of nonlinear differential equations. We analyze this problem for particular cases, both with nonzero and zero viscosity, discuss the question of existence of solutions, and use numerical techniques to describe those solutions that we cannot obtain analytically.
Removing the concavity of the thick center vortex potentials by fluctuating the vortex profile
Sedigheh Deldar; Shahnoosh Rafibakhsh
2010-03-14T23:59:59.000Z
The thick center vortex model reproduces important aspects of the potentials between static quark sources as seen in lattice Yang-Mills calculations: Both the intermediate distance behavior, governed by Casimir scaling, as well as the long distance behavior, governed by N-ality, are obtained. However, when a fixed vortex profile is used, these two distance regimes do not connect naturally to each other. The transition in general violates concavity constraints on the potential, especially for higher representations of the gauge group. We demonstrate how this issue can be alleviated when the vortex profile is allowed to fluctuate within this simple model.
The Aerodynamics of Deforming Wings at Low Reynolds Number
Medina, Albert
2013-01-01T23:59:59.000Z
there develops a Karman vortex street stemming from theedge vortex would occur at the onset of a von Karman street.
Neutron Scattering Studies of Vortex Matter in Type-II Superconductors
Xinsheng Ling
2012-02-02T23:59:59.000Z
The proposed program is an experimental study of the fundamental properties of Abrikosov vortex matter in type-II superconductors. Most superconducting materials used in applications such as MRI are type II and their transport properties are determined by the interplay between random pinning, interaction and thermal fluctuation effects in the vortex state. Given the technological importance of these materials, a fundamental understanding of the vortex matter is necessary. The vortex lines in type-II superconductors also form a useful model system for fundamental studies of a number of important issues in condensed matter physics, such as the presence of a symmetry-breaking phase transition in the presence of random pinning. Recent advances in neutron scattering facilities such as the major upgrade of the NIST cold source and the Spallation Neutron Source are providing unprecedented opportunities in addressing some of the longstanding issues in vortex physics. The core component of the proposed program is to use small angle neutron scattering and Bitter decoration experiments to provide the most stringent test of the Bragg glass theory by measuring the structure factor in both the real and reciprocal spaces. The proposed experiments include a neutron reflectometry experiment to measure the precise Q-dependence of the structure factor of the vortex lattice in the Bragg glass state. A second set of SANS experiments will be on a shear-strained Nb single crystal for testing a recently proposed theory of the stability of Bragg glass. The objective is to artificially create a set of parallel grain boundaries into a Nb single crystal and use SANS to measure the vortex matter diffraction pattern as a function of the changing angle between the applied magnetic field to the grain boundaries. The intrinsic merits of the proposed work are a new fundamental understanding of type-II superconductors on which superconducting technology is based, and a firm understanding of phases and phase transitions in condensed matter systems with random pinning. The broader impact of the program includes the training of future generation of neutron scientists, and further development of neutron scattering and complementary techniques for studies of superconducting materials. The graduate and undergraduate students participating in this project will learn the state-of-the-art neutron scattering techniques, acquire a wide range of materials research experiences, and participate in the frontier research of superconductivity. This should best prepare the students for future careers in academia, industry, or government.
Acoustics of finite-aperture vortex beams
Mitri, F G
2014-01-01T23:59:59.000Z
A method based on the Rayleigh-Sommerfeld surface integral is provided, which makes it feasible to rigorously model, evaluate and compute the acoustic scattering and other mechanical effects of finite-aperture vortex beams such as the acoustic radiation force and torque on a viscoelastic sphere in various applications in acoustic tweezers and microfluidics, particle entrapment, manipulation and rotation. Partial-wave series expansions are derived for the incident field of acoustic spiraling (vortex) beams, comprising high-order Bessel and Bessel-Gauss beams.
Invariants for Tendex and Vortex Fields
Kenneth A. Dennison; Thomas W. Baumgarte
2012-08-06T23:59:59.000Z
Tendex and vortex fields, defined by the eigenvectors and eigenvalues of the electric and magnetic parts of the Weyl curvature tensor, form the basis of a recently developed approach to visualizing spacetime curvature. In analogy to electric and magnetic fields, these fields are coordinate-dependent. However, in a further analogy, we can form invariants from the tendex and vortex fields that are invariant under coordinate transformations, just as certain combinations of the electric and magnetic fields are invariant under coordinate transformations. We derive these invariants, and provide a simple, analytical demonstration for non-spherically symmetric slices of a Schwarzschild spacetime.
Vortex generation in protoplanetary disks with an embedded giant planet
M. de Val-Borro; P. Artymowicz; G. D'Angelo; A. Peplinski
2007-06-21T23:59:59.000Z
Vortices in protoplanetary disks can capture solid particles and form planetary cores within shorter timescales than those involved in the standard core-accretion model. We investigate vortex generation in thin unmagnetized protoplanetary disks with an embedded giant planet with planet to star mass ratio $10^{-4}$ and $10^{-3}$. Two-dimensional hydrodynamical simulations of a protoplanetary disk with a planet are performed using two different numerical methods. The results of the non-linear simulations are compared with a time-resolved modal analysis of the azimuthally averaged surface density profiles using linear perturbation theory. Finite-difference methods implemented in polar coordinates generate vortices moving along the gap created by Neptune-mass to Jupiter-mass planets. The modal analysis shows that unstable modes are generated with growth rate of order $0.3 \\Omega_K$ for azimuthal numbers m=4,5,6, where $\\Omega_K$ is the local Keplerian frequency. Shock-capturing Cartesian-grid codes do not generate very much vorticity around a giant planet in a standard protoplanetary disk. Modal calculations confirm that the obtained radial profiles of density are less susceptible to the growth of linear modes on timescales of several hundreds of orbital periods. Navier-Stokes viscosity of the order $\
Convergenceof Vortex Methods for Weak Solutionsto the
Liu, Jian-Guo
, Krasny applied such a method in his calculations of the evolution of vortex sheetseven past the time when numerical simulations;see Krasny, [16] and [17], and Baker and Shelley, [l]. It is thus important to analyze by Krasny (see [16] and [17]). Our analysis is closely related to that of [9], [lo], and [18], and based
Quenching Processes in Flame-Vortex Interactions
Zingale, Michael
for Astrophysical Thermonuclear Flashes 1 , Chicago, IL 60637 y Department of Astronomy and Astrophysics, University-vortex interactions in order to understand quenching of thermonuclear ames. The key question is|can a ther- monuclear. If a ame encounters a 1) The Center for Astrophysical Thermonuclear Flashes is supported by the Department
Bifurcation to vortex solutions in superconducting lms
Chapman, Jon
Bifurcation to vortex solutions in superconducting #12;lms T. Boeck #3; S.J. Chapman y Mathematical state to a superconducting state in a decreasing magnetic #12;eld is studied for a slab geometry of these behaviours will occur in practice. 1 Introduction If a superconducting body is placed in a suÃ?ciently strong
Carpenter, M. P.; Cizewski, J. A.; Davids, C. N.; Davinson, T.; Fotiades, N.; Henderson, D. J.; Janssens, R. V. F.; Lauritsen, T.; Reiter, P.; Ressler, J. J.; Schwartz, J.; Seweryniak, D.; Sonzogni, A. A.; Uusitalok, J.; Walters, W. B.; Wiedenhover, I. L.; Woods, P. J.
1999-02-17T23:59:59.000Z
The mechanisms of proton radioactivity from deformed rare earth nuclei are discussed and preliminary results on the fine structure decay of {sup 131}Eu are presented.
Gas core nuclear rocket feasibility project
Howe, S.D.; DeVolder, B.; Thode, L.; Zerkle, D.
1997-09-01T23:59:59.000Z
The next giant leap for mankind will be the human exploration of Mars. Almost certainly within the next thirty years, a human crew will brave the isolation, the radiation, and the lack of gravity to walk on and explore the Red planet. However, because the mission distances and duration will be hundreds of times greater than the lunar missions, a human crew will face much greater obstacles and a higher risk than those experienced during the Apollo program. A single solution to many of these obstacles is to dramatically decrease the mission duration by developing a high performance propulsion system. The gas core nuclear rocket (GCNR) has the potential to be such a system. The gas core concept relies on the use of fluid dynamic forces to create and maintain a vortex. The vortex is composed of a fissile material which will achieve criticality and produce high power levels. By radiatively coupling to the surrounding fluids, extremely high temperatures in the propellant and, thus, high specific impulses can be generated. The ship velocities enabled by such performance may allow a 9 month round trip, manned Mars mission to be considered. Alternatively, one might consider slightly longer missions in ships that are heavily shielded against the intense Galactic Cosmic Ray flux to further reduce the radiation dose to the crew. The current status of the research program at the Los Alamos National Laboratory into the gas core nuclear rocket feasibility will be discussed.
Resurgent deformation quantisation
Garay, Mauricio, E-mail: garay91@gmail.com [Institut für Mathematik, FB 08 Physik, Mathematik und Informatik, Johannes Gutenberg-Universität, 55099 Mainz (Germany)] [Institut für Mathematik, FB 08 Physik, Mathematik und Informatik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Goursac, Axel de, E-mail: Axelmg@melix.net [Chargé de Recherche au F.R.S.-FNRS, IRMP, Université Catholique de Louvain, Chemin du Cyclotron, 2, B-1348 Louvain-la-Neuve (Belgium); Straten, Duco van, E-mail: straten@mathematik.uni-mainz.de [Institut für Mathematik, FB 08 Physik, Mathematik und Informatik, Johannes Gutenberg-Universität, 55099 Mainz (Germany)
2014-03-15T23:59:59.000Z
We construct a version of the complex Heisenberg algebra based on the idea of endless analytic continuation. The algebra would be large enough to capture quantum effects that escape ordinary formal deformation quantisation. -- Highlights: •We construct resurgent deformation quantisation. •We give integral formulæ. •We compute examples which show that hypergeometric functions appear naturally in quantum computations.
Llordes, Anna [ICMAB, Barcelona, Spain; Palau, A. [ICMAB, Barcelona, Spain; Gazquez, J. [Oak Ridge National Laboratory (ORNL); Coll, M. [ICMAB, Barcelona, Spain; Vlad, R. [ICMAB, Barcelona, Spain; Pomar, A. [ICMAB, Barcelona, Spain; Arbiol, Jordi [ICMAB, Barcelona, Spain; Guzman, Roger [ICMAB, Barcelona, Spain; Ye, S. [ICMAB, Barcelona, Spain; Rouco, V [ICMAB, Barcelona, Spain; Sandiumenge, Felip [ICMAB, Barcelona, Spain; Ricart, Susagna [ICMAB, Barcelona, Spain; Puig, Teresa [ICMAB, Barcelona, Spain; Varela del Arco, Maria [ORNL; Chataigner, D. [CRISMAT, Caen, France; Vanacken, J. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Gutierrez, J. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Moschalkov, V. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Deutscher, G. [Tel Aviv University; Magen Dominguez, Cesar [ORNL; Obradors, Xavier [ICMAB, Barcelona, Spain
2012-01-01T23:59:59.000Z
Boosting large-scale superconductor applications require nanostructured conductors with artificial pinning centres immobilizing quantized vortices at high temperature and magnetic fields. Here we demonstrate a highly effective mechanism of artificial pinning centers in solution-derived high-temperature superconductor nanocomposites through generation of nanostrained regions where Cooper pair formation is suppressed. The nanostrained regions identified from transmission electron microscopy devise a very high concentration of partial dislocations associated with intergrowths generated between the randomly oriented nanodots and the epitaxial YBa{sub 2}Cu{sub 3}O{sub 7} matrix. Consequently, an outstanding vortex-pinning enhancement correlated to the nanostrain is demonstrated for four types of randomly oriented nanodot, and a unique evolution towards an isotropic vortex-pinning behaviour, even in the effective anisotropy, is achieved as the nanostrain turns isotropic. We suggest a new vortex-pinning mechanism based on the bond-contraction pairing model, where pair formation is quenched under tensile strain, forming new and effective core-pinning regions.
Deterministic Josephson Vortex Ratchet with a load
M. Knufinke; K. Ilin; M. Siegel; D. Koelle; R. Kleiner; E. Goldobin
2011-09-29T23:59:59.000Z
We investigate experimentally a deterministic underdamped Josephson vortex ratchet -- a fluxon-particle moving along a Josephson junction in an asymmetric periodic potential. By applying a sinusoidal driving current one can compel the vortex to move in a certain direction, producing average dc voltage across the junction. Being in such a rectification regime we also load the ratchet, i.e., apply an additional dc bias current I_dc (counterforce) which tilts the potential so that the fluxon climbs uphill due to the ratchet effect. The value of the bias current at which the fluxon stops climbing up defines the strength of the ratchet effect and is determined experimentally. This allows us to estimate the loading capability of the ratchet, the output power and efficiency. For the quasi-static regime we present a simple model which delivers simple analytic expressions for the above mentioned figures of merit.
Vortex state in a doped Mott insulator M. Franz and Z. Tesanovic
Tesanovic, Zlatko
predicts two types of singly quantized vortices: an insulating ``holon'' vortex in the underdoped and a metallic ``spinon'' vortex in the overdoped region of the phase diagram. We argue that the holon vortex
Konstantinos Sfetsos; Daniel C. Thompson
2014-10-07T23:59:59.000Z
We examine a recently proposed class of integrable deformations to two-dimensional conformal field theories. These {\\lambda}-deformations interpolate between a WZW model and the non-Abelian T-dual of a Principal Chiral Model on a group G or, between a G/H gauged WZW model and the non-Abelian T-dual of the geometric coset G/H. {\\lambda}-deformations have been conjectured to represent quantum group q-deformations for the case where the deformation parameter is a root of unity. In this work we show how such deformations can be given an embedding as full string backgrounds whose target spaces satisfy the equations of type-II supergravity. One illustrative example is a deformation of the Sl(2,R)/U(1) black-hole CFT. A further example interpolates between the $\\frac{SU(2)\\times SU(2)}{SU(2)}\\times\\frac{SL(2,R)\\times SL(2,R)}{SL(2,R)} \\times U(1)^4$ gauged WZW model and the non-Abelian T-dual of $AdS_3\\times S^3\\times T^4$ supported with Ramond flux.
Zero-energy states bound to a magnetic pi-flux vortex in a two-dimensional topological insulator
Andrej Mesaros; Robert-Jan Slager; Jan Zaanen; Vladimir Juricic
2012-10-22T23:59:59.000Z
We show that the existence of a pair of zero-energy modes bound to a vortex carrying a pi-flux is a generic feature of the topologically non-trivial phase of the M-B model, which was introduced to describe the topological band insulator in HgTe quantum wells. We explicitly find the form of the zero-energy states of the corresponding Dirac equation, which contains a novel momentum-dependent mass term and describes a generic topological transition in a band insulator. The obtained modes are exponentially localized in the vortex-core, with the dependence of characteristic length on the parameters of the model matching the dependence extracted from a lattice version of the model. We consider in full generality the short-distance regularization of the vector potential of the vortex, and show that a particular choice yields the modes localized and simultaneously regular at the origin. Finally, we also discuss a realization of two-dimensional spin-charge separation through the vortex zero-modes.
Multiple precision, multiple processor vortex sheet roll-up computation
Bailey, D.H. [NASA Ames Research Center, Moffett Field, CA (United States); Krasny, R. [Univ. of Michigan, Ann Arbor, MI (United States); Pelz, R. [Rutgers Univ., Piscataway, NJ (United States)
1993-12-31T23:59:59.000Z
A vortex sheet in incompressible flow is a surface across which the tangential fluid velocity has a jump discontinuity. A basic idea in fluid dynamics going back to Prandtl is that the vortex sheet can be obtained as the zero viscosity limit of a sequence of smooth solutions to the Navier-Stokes equations. Thus, the investigation of vortex sheet motion may yield insight into the structure of high Reynolds number flow.
Optical vortex interaction and generation via nonlinear wave mixing
Lenzini, F. [INLN, Universite de Nice-Sophia Antipolis, CNRS, 1361 route des Lucioles, FR-06560 Valbonne (France); Dipartimento di Fisica, Universita di Firenze, via Sansone 1, IT-50019 Sesto Fiorentino (Italy); Residori, S.; Bortolozzo, U. [INLN, Universite de Nice-Sophia Antipolis, CNRS, 1361 route des Lucioles, FR-06560 Valbonne (France); Arecchi, F. T. [Dipartimento di Fisica, Universita di Firenze, via Sansone 1, IT-50019 Sesto Fiorentino (Italy)
2011-12-15T23:59:59.000Z
Optical vortex beams are made to interact via degenerate two-wave mixing in a Kerr-like nonlinear medium. Vortex mixing is shown to occur inside the medium, leading to exchange of topological charge and cascaded generation of vortex beams. A mean-field model is developed and is shown to account for the selection rules of the topological charges observed after the wave-mixing process. Fractional charges are demonstrated to follow the same rules as for integer charges.
Laboratory Analysis of Vortex Dynamics For Shallow Tidal Inlets
Whilden, Kerri Ann
2010-10-12T23:59:59.000Z
of the secondary structures into the vortex system are shown as well as variations in characteristics such as trajectory, size, vorticity, and circulation for the vortices as they move downstream. iv To the loved ones who have encouraged me along the way. v.... : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 30 13 Non-Dimensional Vorticity at the Swirl Strength Peak for the Pri- mary Vortex Within the Vortex System Versus Non-Dimensional Horizontal Location of the Centroid. : : : : : : : : : : : : : : : : : : 31 14 Non-Dimensional Circulation...
E Amiguet; P Cordier; P Raterron
2011-12-31T23:59:59.000Z
The dislocation microstructures of diopside single crystals deformed at high-pressure (4 {<=} P {<=} 9 GPa), high-temperature (1100{sup o} {<=} T {<=} 1400 {sup o}C) using a Deformation-DIA high-pressure apparatus (D-DIA) have been characterized by transmission electron microscopy using weak-beam dark-field (WBDF), precession electron diffraction (PED), large-angle convergent-beam electron diffraction (LACBED) and the thickness-fringe method. Dislocation glide is the dominant deformation mechanism under these conditions. The 1/2<110>{l_brace}110{r_brace} glide is controlled by lattice friction on the edge segments and shows extensive cross-slip. The [001] glide occurs mostly on {l_brace}110{r_brace}; no evidence for [001](010) glide has been found. The [100] dislocations bear a strong lattice friction probably due to complex (out of glide) core structures.
Liquid Vortex Shielding for Fusion Energy Applications
Bardet, Philippe M. [University of California, Berkeley (United States); Supiot, Boris F. [University of California, Berkeley (United States); Peterson, Per F. [University of California, Berkeley (United States); Savas, Oemer [University of California, Berkeley (United States)
2005-05-15T23:59:59.000Z
Swirling liquid vortices can be used in fusion chambers to protect their first walls and critical elements from the harmful conditions resulting from fusion reactions. The beam tube structures in heavy ion fusion (HIF) must be shielded from high energy particles, such as neutrons, x-rays and vaporized coolant, that will cause damage. Here an annular wall jet, or vortex tube, is proposed for shielding and is generated by injecting liquid tangent to the inner surface of the tube both azimuthally and axially. Its effectiveness is closely related to the vortex tube flow properties. 3-D particle image velocimetry (PIV) is being conducted to precisely characterize its turbulent structure. The concept of annular vortex flow can be extended to a larger scale to serve as a liquid blanket for other inertial fusion and even magnetic fusion systems. For this purpose a periodic arrangement of injection and suction holes around the chamber circumference are used, generating the layer. Because it is important to match the index of refraction of the fluid with the tube material for optical measurement like PIV, a low viscosity mineral oil was identified and used that can also be employed to do scaled experiments of molten salts at high temperature.
active vortex generators: Topics by E-print Network
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how an initial dusturbing cyclonic vortex is created by collision between two linear wind jets under certain conditions, which under favorable conditions, may mature into a...
Tomoya Isoshima; Kazushige Machida
1999-02-27T23:59:59.000Z
The instability condition of the non-vortex state toward vortex formation is exa mined within the Bogoliubov theory when a Bose-Einstein condensate is under exte rnally forced rotation. The obtained critical angular velocity combined with the previous stability cond itions for a votex yields a detailed phase diagram in the critical velocity vs t he system parameter. This facilitates vortex formation experiments for alkali atom gases confined in a harmonic potential.
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisitingContract Management Fermi Site Office (FSO) FSOConvertingCopy ServicesCore
Center Manifold Analysis of a PointVortex Model of Vortex Shedding with Control
Protas, Bartosz
of the point vortex FÂ¨oppl system with linear feedback control. The FÂ¨oppl system was used in an earlier system. Key words: point vortices, flow control, dynamical systems, wake flows PACS: 47.15.Hg, 47.27.Rc, 47.27.Vf 1 Introduction Integration of rigorous methods of Modern Control Theory with Computational
Center Vortex vs. Abelian models of the QCD vacuum
Höllwieser, Roman
2015-01-01T23:59:59.000Z
We present evidence that the center vortex model of confinement is more consistent with lattice results than other currently available models. In particular we show that Abelian field distributions predicted by monopole plasma, caloron gas or dual superconductor models cannot reproduce the area-law falloff of double winding Wilson loops in full $SU(2)$ and center vortex only gauge fields.
Vortex Lattice Modelling of Winglets on Wind Turbine Blades
Vortex Lattice Modelling of Winglets on Wind Turbine Blades Mads DÃ¸ssing RisÃ¸-R-1621(EN) RisÃ¸ Title: Vortex Lattice Modelling of Winglets on Wind Turbine Blades Departments: Wind Energy Department turbines can be increased by the use of winglets without increasing the swept area. This makes them
Geometrical statistics and vortex structures in helical and nonhelical turbulences
Li, Yi
, United Kingdom Received 4 August 2009; accepted 20 January 2010; published online 9 March 2010 explained in terms of the self-induced motions of local vortex structures, which tend to wind up the vortexÂ11,13Â15 the effects of helicity on energy cascade,16 the interaction between helicity and energy dissipation,17
Electron vortex beams in a magnetic field and spin filter
Debashree Chowdhury; Banasri Basu; Pratul Bandyopadhyay
2015-02-25T23:59:59.000Z
We investigate the propagation of electron vortex beams in a magnetic field. It is pointed out that when electron vortex beams carrying orbital angular momentum propagate in a magnetic field, the Berry curvature associated with the scalar electron moving in a cyclic path around the vortex line is modified from that in free space. This alters the spin-orbit interaction, which affects the propagation of nonparaxial beams. The electron vortex beams with tilted vortex lead to spin Hall effect in free space. In presence of a magnetic field in time space we have spin filtering such that either positive or negative spin states emerge in spin Hall currents with clustering of spin $\\frac{1}{2}$ states.
Vortex and Droplet Engineering in Holographic Superconductors
Tameem Albash; Clifford V. Johnson
2009-08-22T23:59:59.000Z
We give a detailed account of the construction of non--trivial localized solutions in a 2+1 dimensional model of superconductors using a 3+1 dimensional gravitational dual theory of a black hole coupled to a scalar field. The solutions are found in the presence of a background magnetic field. We use numerical and analytic techniques to solve the full Maxwell--scalar equations of motion in the background geometry, finding condensate droplet solutions, and vortex solutions possessing a conserved winding number. These solutions and their properties, which we uncover, help shed light on key features of the (B,T) phase diagram.
Vortex lattice for a holographic superconductor
Kengo Maeda; Makoto Natsuume; Takashi Okamura
2009-12-17T23:59:59.000Z
We investigate the vortex lattice solution in a (2+1)-dimensional holographic model of superconductors constructed from a charged scalar condensate. The solution is obtained perturbatively near the second-order phase transition and is a holographic realization of the Abrikosov lattice. Below a critical value of magnetic field, the solution has a lower free energy than the normal state. Both the free energy density and the superconducting current are expressed by nonlocal functions, but they reduce to the expressions in the Ginzburg-Landau (GL) theory at long wavelength. As a result, a triangular lattice becomes the most favorable solution thermodynamically as in the GL theory of type II superconductors.
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Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
consists mostly of oxygen, silicon, and magnesium, often in the form of magnesium silicate (MgSiO3). In the lower mantle, this magnesium silicate has a crystal structure known...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA / USACE625Data ShowCDevelopment33.0 8.0 3.4i MineSeis
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA / USACE625Data ShowCDevelopment33.0 8.0 3.4i
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA / USACE625Data ShowCDevelopment33.0 8.0 3.4iMineral
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA / USACE625Data ShowCDevelopment33.0 8.0
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA / USACE625Data ShowCDevelopment33.0 8.0Mineral
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA / USACE625Data ShowCDevelopment33.0 8.0MineralMineral
Rohde, Axel
and 1000 diameters, alternate vortex shedding begins, and a von Karman vortex street develops in the wake of Vortex Instability in a 2-D Compressible Flow over a Cylinder Axel Rohde Department of Aerospace start and reveals the evolution of vortex instability. After the cylinder has traveled between 100
Electrically Deformable Liquid Marbles
Edward Bormashenko; Roman Pogreb; Tamir Stein; Gene Whyman; Marcelo Schiffer; Doron Aurbach
2011-02-17T23:59:59.000Z
Liquid marbles, which are droplets coated with a hydrophobic powder, were exposed to a uniform electric field. It was established that a threshold value of the electric field, 15 cgse, should be surmounted for deformation of liquid marbles. The shape of the marbles was described as a prolate spheroid. The semi-quantitative theory describing deformation of liquid marbles in a uniform electric field is presented. The scaling law relating the radius of the contact area of the marble to the applied electric field shows a satisfactory agreement with the experimental data.
Nanolaminate deformable mirrors
Papavasiliou, Alexandros P. (Oakland, CA); Olivier, Scot S. (Santa Cruz, CA)
2009-04-14T23:59:59.000Z
A deformable mirror formed out of two layers of a nanolaminate foil attached to a stiff substrate is introduced. Deformation is provided by an electrostatic force between two of the layers. The internal stiffness of the structure allows for high-spatial-frequency shapes. The nanolaminate foil of the present invention allows for a high-quality mirror surface. The device achieves high precision in the vertical direction by using foils with accurately controlled thicknesses, but does not require high precision in the lateral dimensions, allowing such mirrors to be fabricated using crude lithography techniques. Such techniques allow structures up to about the meter scale to be fabricated.
Nanolaminate deformable mirrors
Papavasiliou, Alexandros P.; Olivier, Scot S.
2010-04-06T23:59:59.000Z
A deformable mirror formed out of two layers of a nanolaminate foil attached to a stiff substrate is introduced. Deformation is provided by an electrostatic force between two of the layers. The internal stiffness of the structure allows for high-spatial-frequency shapes. The nanolaminate foil of the present invention allows for a high-quality mirror surface. The device achieves high precision in the vertical direction by using foils with accurately controlled thicknesses, but does not require high precision in the lateral dimensions, allowing such mirrors to be fabricated using crude lithography techniques. Such techniques allow structures up to about the meter scale to be fabricated.
Non-Riemannian geometry of vortex acoustics
Garcia de Andrade, L.C. [Departamento de Fisica Teorica, Instituto de Fisica, Universidade Estadual do Rio de Janeiro, Rua Sao Francisco Xavier 524, Maracana, 20550, Rio de Janeiro, RJ (Brazil)
2004-09-15T23:59:59.000Z
The concept of acoustic torsion is introduced by making use of the scalar wave equation in Riemann-Cartan spacetime. Acoustic torsion extends the acoustic metric previously given by Unruh (PRL-1981). The wave equation describes irrotational perturbations in rotational nonrelativistic fluids. This physical motivation allows us to show that the acoustic line element can be conformally mapped to the line element of a stationary torsion loop in non-Riemannian gravity. Two examples of such sonic analogues are given. The first is the stationary torsion loop in teleparallel gravity. In the far from the vortex approximation, the Cartan torsion vector is shown to be proportional to the quantum vortex number of the superfluid. The torsion vector is also shown to be proportional to the superfluid vorticity in the presence of vortices. The formation of superfluid vortices is shown not to be favored by torsion loops in Riemann-Cartan spacetime, as long as this model is concerned. It is suggested that the teleparallel model may help to find a model for superfluid neutron stars vortices based on non-Riemannian gravity.
Ferroelectric nanostructure having switchable multi-stable vortex states
Naumov, Ivan I. (Fayetteville, AR); Bellaiche, Laurent M. (Fayetteville, AR); Prosandeev, Sergey A. (Fayetteville, AR); Ponomareva, Inna V. (Fayetteville, AR); Kornev, Igor A. (Fayetteville, AR)
2009-09-22T23:59:59.000Z
A ferroelectric nanostructure formed as a low dimensional nano-scale ferroelectric material having at least one vortex ring of polarization generating an ordered toroid moment switchable between multi-stable states. A stress-free ferroelectric nanodot under open-circuit-like electrical boundary conditions maintains such a vortex structure for their local dipoles when subject to a transverse inhomogeneous static electric field controlling the direction of the macroscopic toroidal moment. Stress is also capable of controlling the vortex's chirality, because of the electromechanical coupling that exists in ferroelectric nanodots.
Vortex structures and zero-energy states in the BCS-to-BEC evolution of p-wave resonant Fermi gases
Mizushima, T.; Machida, K. [Department of Physics, Okayama University, Okayama 700-8530 (Japan)
2010-05-15T23:59:59.000Z
Multiply quantized vortices in the BCS-to-BEC (Bose-Einstein condensation) evolution of p-wave resonant Fermi gases are investigated theoretically. The vortex structure and the low-energy quasiparticle states are discussed, based on the self-consistent calculations of the Bogoliubov-de Gennes and gap equations. We reveal the direct relation between the macroscopic structure of vortices, such as particle densities, and the low-lying quasiparticle state. In addition, the net angular momentum for multiply quantized vortices with a vorticity {kappa} is found to be expressed by a simple equation, which reflects the chirality of the Cooper pairing. Hence, the observation of the particle density depletion and the measurement of the angular momentum will provide the information on the core-bound state and p-wave superfluidity. Moreover, the details on the zero energy Majorana state are discussed in the vicinity of the BCS-to-BEC evolution. It is demonstrated numerically that the zero energy Majorana state appears in the weak coupling BCS limit only when the vortex winding number is odd. The {kappa} branches of the core-bound states for a vortex state with vorticity {kappa} exist; however, only one of them can be the zero energy. This zero energy state vanishes at the BCS-BEC topological phase transition because of interference between the core-bound and edge-bound states.
Sound Wave in Vortex with Sink
Soumen Basak
2003-11-17T23:59:59.000Z
Using Komar's definition, we give expressions for the mass and angular momentum of a rotating acoustic black hole. We show that the mass and angular momentum so defined, obey the equilibrium version of the first law of Black Hole thermodynamics. We also show that when a phonon passes by a vortex with a sink, its trajectory is bent. The angle of bending of the sound wave to leading order is quadratic in $A/cb$ and $B/cb$, where $b$ is the impact parameter and $A$ and $B$ are the parameters in the velocity of the fluid flow. The time delay in the propagation of sound wave which to first order depends only on $B/c^2$ and is independent of $A$.
Loop-deformed Poincaré algebra
Jakub Mielczarek
2013-04-08T23:59:59.000Z
In this essay we present evidence suggesting that loop quantum gravity leads to deformation of the local Poincar\\'e algebra within the limit of high energies. This deformation is a consequence of quantum modification of effective off-shell hypersurface deformation algebra. Surprisingly, the form of deformation suggests that the signature of space-time changes from Lorentzian to Euclidean at large curvatures. We construct particular realization of the loop-deformed Poincar\\'e algebra and find that it can be related to curved momentum space, which indicates the relationship with recently introduced notion of relative locality. The presented findings open a new way of testing loop quantum gravity effects.
Fuel injection of coal slurry using vortex nozzles and valves
Holmes, Allen B. (Rockville, MD)
1989-01-01T23:59:59.000Z
Injection of atomized coal slurry fuel into an engine combustion chamber is achieved at relatively low pressures by means of a vortex swirl nozzle. The outlet opening of the vortex nozzle is considerably larger than conventional nozzle outlets, thereby eliminating major sources of failure due to clogging by contaminants in the fuel. Control fluid, such as air, may be used to impart vorticity to the slurry and/or purge the nozzle of contaminants during the times between measured slurry charges. The measured slurry charges may be produced by a diaphragm pump or by vortex valves controlled by a separate control fluid. Fluidic circuitry, employing vortex valves to alternatively block and pass cool slurry fuel flow, is disclosed.
Zero-Energy Flows and Vortex Patterns in Quantum Mechanics
Tsunehiro Kobayashi
2003-02-20T23:59:59.000Z
We show that zero-energy flows appear in many particle systems as same as in single particle cases in 2-dimensions. Vortex patterns constructed from the zero-energy flows can be investigated in terms of the eigenstates in conjugate spaces of Gel'fand triplets. Stable patterns are written by the superposition of zero-energy eigenstates. On the other hand vortex creations and annihilations are described by the insertions of unstable eigenstates with complex-energy eigenvalues into the stable patterns. Some concrete examples are presented in the 2-dimensional parabolic potential barrier case. %, i.e., $-m \\gamma^2 (x^2+y^2)/2$. We point out three interesting properties of the zero-energy flows; (i) the absolute economy as for the energy consumption, (ii) the infinite variety of the vortex patterns, and (iii) the absolute stability of the vortex patterns .
axisymmetric vortex breakdown: Topics by E-print Network
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Fluid Motion at the 66th Annual Meeting of the APS Division of Fluid Dynamics. Kleckner, Dustin; Irvine, William T M 2013-01-01 325 The Taylor-vortex dynamo Christophe Gissinger...
Desingularization of periodic vortex sheet roll-up
Krasny, R.
1986-08-01T23:59:59.000Z
The equations governing periodic vortex sheet roll-up from analytic initial data are desingularized. Linear stability analysis shows that this diminishes the vortex sheet model's short wavelength instability, yielding a numerically more tractable set of equations. Computational evidence is presented which indicates that this approximation converges, beyond the critical time of singularity formation in the vortex sheet, if the mesh is refined and the smoothing parameter is reduced in the proper order. The results suggest that the vortex sheet rolls up into a double branched spiral past the critical time. It is demonstrated that either higher machine precision or a spectra filter can be used to maintain computational accuracy as the smoothing parameter is decreased. Some conjectures on the model's long time asymptotic state are given.
Vortex-induced vibration of slender structures in unsteady flow
Liao, Jung-Chi, 1971-
2002-01-01T23:59:59.000Z
Vortex-induced vibration (VIV) results in fatigue damage of offshore oil exploration and production structures. In recent years, the offshore industry has begun to employ curved slender structures such as steel catenary ...
Drag amplification and fatigue damage in vortex-induced vibrations
Jhingran, Vikas Gopal
2008-01-01T23:59:59.000Z
Fatigue damage and drag force amplification due to Vortex-Induced-Vibrations (VIV) continue to cause significant problems in the design of structures which operate in ocean current environments. These problems are magnified ...
Vortex hair on AdS black holes
Gregory, Ruth; Kubiznak, David; Mann, Robert B; Wills, Danielle
2014-01-01T23:59:59.000Z
We analyse vortex hair for charged rotating asymptotically AdS black holes in the abelian Higgs model. We give analytical and numerical arguments to show how the vortex interacts with the horizon of the black hole, and how the solution extends to the boundary. The solution is very close to the corresponding asymptotically flat vortex, once one transforms to a frame that is non-rotating at the boundary. We show that there is a Meissner effect for extremal black holes, with the vortex flux being expelled from sufficiently small black holes. The phase transition is shown to be first order in the presence of rotation, but second order without rotation. We comment on applications to holography.
Nonclassicality of vortex Airy beams in the Wigner representation
Chen Ruipin [School of Sciences, Zhejiang A and F University, Lin'an, Zhejiang Province 311300 (China); Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Ooi, C. H. Raymond [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)
2011-10-15T23:59:59.000Z
The Wigner distribution function (WDF) of a vortex Airy beam is calculated analytically. The WDF provides intuitive pictures of the intriguing features of vorticity in phase space. The nonclassical property of the vortex Airy beam and the Airy beam is analyzed through the negative parts of the WDF. The study shows that destructive interference of certain classical waves can mimic nonclassical lights such as those due to quantum effects.
Deflection Measurements of a Thermally Simulated Nuclear Core using a High-Resolution CCD-Camera
Stanojev, B.J. [Marshall Space Flight Center, National Aeronautics and Space Administration, Huntsville, Al, 35812 (United States); Houts, M. [Los Alamos National Laboratory, Department of Energy, Los Alamos, NM, 87545 (United States)
2004-07-01T23:59:59.000Z
Space fission systems under consideration for near-term missions all use compact, fast-spectrum reactor cores. Reactor dimensional change with increasing temperature, which affects neutron leakage, is the dominant source of reactivity feedback in these systems. Accurately measuring core dimensional changes during realistic non-nuclear testing is therefore necessary in predicting the system 'nuclear' equivalent behavior. This paper discusses one key technique being evaluated for measuring such changes. The proposed technique is to use a Charged Couple Device (CCD) sensor to obtain deformation readings of electrically heated prototypic reactor core geometry. This paper introduces a technique by which a single high spatial resolution CCD camera is used to measure core deformation in Real-Time (RT). Initial system checkout results are presented along with a discussion on how additional cameras could be used to achieve a three-dimensional deformation profile of the core during test. (authors)
Turbine component casting core with high resolution region
Kamel, Ahmed; Merrill, Gary B.
2014-08-26T23:59:59.000Z
A hollow turbine engine component with complex internal features can include a first region and a second, high resolution region. The first region can be defined by a first ceramic core piece formed by any conventional process, such as by injection molding or transfer molding. The second region can be defined by a second ceramic core piece formed separately by a method effective to produce high resolution features, such as tomo lithographic molding. The first core piece and the second core piece can be joined by interlocking engagement that once subjected to an intermediate thermal heat treatment process thermally deform to form a three dimensional interlocking joint between the first and second core pieces by allowing thermal creep to irreversibly interlock the first and second core pieces together such that the joint becomes physically locked together providing joint stability through thermal processing.
Alleviation of fuselage form drag using vortex flows: Final report
Wortman, A.
1987-09-15T23:59:59.000Z
The concept of using vortex generators to reduce the fuselage form drag of transport aircraft combines the outflow from the plane of symmetry which is induced by the rotational component of the vortex flow with the energization of the boundary layer to reduce the momentum thickness and to delay or eliminate flow separation. This idea was first advanced by the author in 1981. Under a DOE grant, the concept was validated in wind tunnel tests of approximately 1:17 scale models of fuselages of Boeing 747 and Lockheed C-5 aircraft. The search for the minimum drag involved three vortex generator configurations with three sizes of each in six locations clustered in the aft regions of the fuselages at the beginning of the tail upsweep. The local Reynolds number, which is referred to the length of boundary layer run from the nose, was approximately 10{sup 7} so that a fully developed turbulent boundary layer was present. Vortex generator planforms ranged from swept tapered, through swept straight, to swept reverse tapered wings whose semi-spans ranged from 50% to 125% of the local boundary layer thickness. Pitch angles of the vortex generators were varied by inboard actuators under the control of an external proportional digital radio controller. It was found that certain combinations of vortex generator parameters increased drag. However, with certain configurations, locations, and pitch angles of vortex generators, the highest drag reductions were 3% for the 747 and about 6% for the C-5, thus confirming the arguments that effectiveness increases with the rate of upsweep of the tail. Greatest gains in performance are therefore expected on aft loading military transports. 10 refs., 11 figs., 1 tab.
A PARAMETER STUDY FOR BAROCLINIC VORTEX AMPLIFICATION
Raettig, Natalie; Klahr, Hubert [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Lyra, Wladimir, E-mail: raettig@mpia.de, E-mail: klahr@mpia.de, E-mail: Wladimir.Lyra@jpl.nasa.gov [Department of Astrophysics, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024 (United States)
2013-03-10T23:59:59.000Z
Recent studies have shown that baroclinic vortex amplification is strongly dependent on certain factors, namely, the global entropy gradient, the efficiency of thermal diffusion and/or relaxation as well as numerical resolution. We conduct a comprehensive study of a broad range and combination of various entropy gradients, thermal diffusion and thermal relaxation timescales via local shearing sheet simulations covering the parameter space relevant for protoplanetary disks. We measure the Reynolds stresses as a function of our control parameters and see that there is angular momentum transport even for entropy gradients as low as {beta} = -dln s/dln r = 1/2. Values we expect in protoplanetary disks are between {beta} = 0.5-2.0 The amplification-rate of the perturbations, {Gamma}, appears to be proportional to {beta}{sup 2} and thus proportional to the square of the Brunt-Vaeisaelae frequency ({Gamma}{proportional_to}{beta}{sup 2}{proportional_to}N {sup 2}). The saturation level of Reynolds stresses, on the other hand, seems to be proportional to {beta}{sup 1/2}. This highlights the importance of baroclinic effects even for the low entropy gradients expected in protoplanetary disks.
Ultra-Low NOx Advanced Vortex Combustor
Edmonds, R.G. (Ramgen Power Systems, Inc., Bellevue, WA); Steele, R.C. (Ramgen Power Systems, Inc., Bellevue, WA); Williams, J.T. (Ramgen Power Systems, Inc., Bellevue, WA); Straub, D.L.; Casleton, K.H.; Bining, Avtar (California Energy Commission, Sacramento, CA)
2006-05-01T23:59:59.000Z
An ultra lean-premixed Advanced Vortex Combustor (AVC) has been developed and tested. The natural gas fueled AVC was tested at the U.S. Department of Energy’s National Energy Technology Laboratory (USDOE NETL) test facility in Morgantown (WV). All testing was performed at elevated pressures and inlet temperatures and at lean fuel-air ratios representative of industrial gas turbines. The improved AVC design exhibited simultaneous NOx/CO/UHC emissions of 4/4/0 ppmv (all emissions are at 15% O2 dry). The design also achieved less than 3 ppmv NOx with combustion efficiencies in excess of 99.5%. The design demonstrated tremendous acoustic dynamic stability over a wide range of operating conditions which potentially makes this approach significantly more attractive than other lean premixed combustion approaches. In addition, a pressure drop of 1.75% was measured which is significantly lower than conventional gas turbine combustors. Potentially, this lower pressure drop characteristic of the AVC concept translates into overall gas turbine cycle efficiency improvements of up to one full percentage point. The relatively high velocities and low pressure drops achievable with this technology make the AVC approach an attractive alternative for syngas fuel applications.
ULTRA-LOW NOX ADVANCED VORTEX COMBUSTOR
Ryan G. Edmonds; Robert C. Steele; Joseph T. Williams; Douglas L. Straub; Kent H. Casleton; Avtar Bining
2006-05-01T23:59:59.000Z
An ultra lean-premixed Advanced Vortex Combustor (AVC) has been developed and tested. The natural gas fueled AVC was tested at the U.S. Department of Energy’s National Energy Technology Laboratory (USDOE NETL) test facility in Morgantown (WV). All testing was performed at elevated pressures and inlet temperatures and at lean fuel-air ratios representative of industrial gas turbines. The improved AVC design exhibited simultaneous NOx/CO/UHC emissions of 4/4/0 ppmv (all emissions are at 15% O2 dry). The design also achieved less than 3 ppmv NOx with combustion efficiencies in excess of 99.5%. The design demonstrated tremendous acoustic dynamic stability over a wide range of operating conditions which potentially makes this approach significantly more attractive than other lean premixed combustion approaches. In addition, a pressure drop of 1.75% was measured which is significantly lower than conventional gas turbine combustors. Potentially, this lower pressure drop characteristic of the AVC concept translates into overall gas turbine cycle efficiency improvements of up to one full percentage point. The relatively high velocities and low pressure drops achievable with this technology make the AVC approach an attractive alternative for syngas fuel applications.
Visualization of Intricate Flow Structures for Vortex Breakdown Analysis Xavier Tricoche
Utah, University of
Visualization of Intricate Flow Structures for Vortex Breakdown Analysis Xavier Tricoche University, synthetic depictions that permit new insight into the structural properties of vortex breakdowns. CR And Modeling-- Simulation Output Analysis J.2 [Physical Sciences and Engineer- ing]: Engineering--. Keywords
Experimental Investigations of Vortex Induced Vibration of A Flat Plate in Pitch Oscillation
Yang, Yi
2012-02-14T23:59:59.000Z
A bluff structure placed in a flowing fluid, may be subjected to vortex-induced vibrations (VIV). For a flat plate with only rotational degree of freedom, the VIV is rotational oscillation. Based on the experimental investigation, vortex...
Mountziaris, T. J.
Vortex Shedding from Superhydrophobic Cylinders Nangelie Ferrer, Robert Daniello and Jonathan Rothstein University of Massachusetts Amherst Abstract Superhydrophobic surfaces are ideal for applications to characterize the vortex shedding phenomenon observed within the wake region of the superhydrophobic cylinder
Deformation Expression for Elements of Algebra
H. Omori; Y. Maeda; N. Miyazaki; A. Yoshioka
2011-04-09T23:59:59.000Z
The purpose of this paper is to give a notion of deformation of expressions for elements of algebra. Deformation quantization (cf.[BF]) deforms the commutative world to a non-commutative world. However, this involves deformation of expression of elements of algebras even from a commutative world to another commutative world. This is indeed a deformation of expressions for elements of algebra.
Wave–vortex interactions in the nonlinear Schrödinger equation
Guo, Yuan, E-mail: yuanguo@cims.nyu.edu; Bühler, Oliver [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)] [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)
2014-02-15T23:59:59.000Z
This is a theoretical study of wave–vortex interaction effects in the two-dimensional nonlinear Schrödinger equation, which is a useful conceptual model for the limiting dynamics of superfluid quantum condensates at zero temperature. The particular wave–vortex interaction effects are associated with the scattering and refraction of small-scale linear waves by the straining flows induced by quantized point vortices and, crucially, with the concomitant nonlinear back-reaction, the remote recoil, that these scattered waves exert on the vortices. Our detailed model is a narrow, slowly varying wavetrain of small-amplitude waves refracted by one or two vortices. Weak interactions are studied using a suitable perturbation method in which the nonlinear recoil force on the vortex then arises at second order in wave amplitude, and is computed in terms of a Magnus-type force expression for both finite and infinite wavetrains. In the case of an infinite wavetrain, an explicit asymptotic formula for the scattering angle is also derived and cross-checked against numerical ray tracing. Finally, under suitable conditions a wavetrain can be so strongly refracted that it collapses all the way onto a zero-size point vortex. This is a strong wave–vortex interaction by definition. The conditions for such a collapse are derived and the validity of ray tracing theory during the singular collapse is investigated.
Nonexistence of Lyapunov Functions and the Instability of the von Karman Vortex Streets
Lim, Chjan C.
Nonexistence of Lyapunov Functions and the Instability of the von Karman Vortex Streets Chjan Lim of the von Karman vortex streets and the existence of a global Lyapunov function at the special aspect ratio the equilibrium Karman streets are unlikely theoretical candidates for observed vortex trails. On the other hand
Hu, Hui
of the reverse von Karman vortex street behind the flapping wing. However, it is challenging to fully understandExperimental and Numerical Investigations on the Asymmetric Wake Vortex Structures around of the vortex pair becomes more apparent, which is considered to be a vital element to form the asymmetric wake
The effect of surface tension on the Moore singularity of vortex sheet dynamics
Fontelos, Marco
The effect of surface tension on the Moore singularity of vortex sheet dynamics F. de la Hoz , M's singularities by surface tension in the evolution of vortex sheets and its dependence on Weber number (which is inversely proportional to surface tension coefficient). The curvature of the vortex sheet, instead
Traveling Waves from the Arclength Parameterization: Vortex Sheets with Surface Tension
Wright, J. Douglas
Traveling Waves from the Arclength Parameterization: Vortex Sheets with Surface Tension Benjamin for the vortex sheet with surface tension. We use the angle- arclength description of the interface rather than prove that there exist traveling vortex sheets with surface tension bifurcating from equilibrium. We
Casten, R.F.; Warner, D.D.
1982-01-01T23:59:59.000Z
The structure and characteristic properties and predictions of the IBA in deformed nuclei are reviewed, and compared with experiment, in particular for /sup 168/Er. Overall, excellent agreement, with a minimum of free parameters (in effect, two, neglecting scale factors on energy differences), was obtained. A particularly surprising, and unavoidable, prediction is that of strong ..beta.. ..-->.. ..gamma.. transitions, a feature characteristically absent in the geometrical model, but manifest empirically. Some discrepancies were also noted, principally for the K=4 excitation, and the detailed magnitudes of some specific B(E2) values. Considerable attention is paid to analyzing the structure of the IBA states and their relation to geometric models. The bandmixing formalism was studied to interpret both the aforementioned discrepancies and the origin of the ..beta.. ..-->.. ..gamma.. transitions. The IBA states, extremely complex in the usual SU(5) basis, are transformed to the SU(3) basis, as is the interaction Hamiltonian. The IBA wave functions appear with much simplified structure in this way as does the structure of the associated B(E2) values. The nature of the symmetry breaking of SU(3) for actual deformed nuclei is seen to be predominantly ..delta..K=0 mixing. A modified, and more consistent, formalism for the IBA-1 is introduced which is simpler, has fewer free parameters (in effect, one, neglecting scale factors on energy differences), is in at least as good agreement with experiment as the earlier formalism, contains a special case of the 0(6) limit which corresponds to that known empirically, and appears to have a close relationship to the IBA-2. The new formalism facilitates the construction of contour plots of various observables (e.g., energy or B(E2) ratios) as functions of N and chi/sub Q/ which allow the parameter-free discussion of qualitative trajectories or systematics.
Broader source: Energy.gov [DOE]
Tank Farms workers demonstrate core drilling capabilities for Hanford single-shell tanks. Core drilling is used to determine the current condition of each tank to assist in the overall assessment...
Morita Equivalence in Deformation Quantization Henrique Bursztyn
Bursztyn, Henrique
Morita Equivalence in Deformation Quantization by Henrique Bursztyn Engineer (Universidade Federal at Berkeley Spring 2001 #12;Morita Equivalence in Deformation Quantization Copyright 2001 by Henrique Bursztyn #12;1 Abstract Morita Equivalence in Deformation Quantization by Henrique Bursztyn Doctor
Hydrodynamic loads on flexible marine structures due to vortex shedding
Every, M.J.; King, R.
1982-12-01T23:59:59.000Z
This paper makes a comparison of experimental measurements and a recently developed methodology for the prediction of the increase in the steady drag of a cylinder undergoing vortex-induced vibrations. The experimental results were obtained during the development of a means to reduce the flow-induced vibration of a cable-suspended pile of the COGNAC platform installation and agree well with the predictions made in this paper. Next, a brief consideration is made of some of the authors' experience of methods used to reduce vortex-induced vibrations, and hence stress levels. Finally, a reduction method which used an air-blowing manifold is described and results presented.
Finite Element Modeling of Drilling Using DEFORM
Gardner, Joel D.; Dornfeld, David
2006-01-01T23:59:59.000Z
Vijayaraghavan, A. (2005), “Drilling of Fiber- ReinforcedFINITE ELEMENT MODELING OF DRILLING USING DEFORM J. Gardner,of Comprehensive Drilling Simulation Tool” ABSTRACT DEFORM-
Wesfreid, José Eduardo
, concentrated vorticity can appear as a result of instabilities such as the BCnard-Von Karman vortex street vortex P. PETITJEANS `*, J. H. ROBRES a, J. E. WESFREID a, N. KEVLAHAN b ABSTRACT. - Experimental vortex (which is a non-confined stretched vortex model) are observed and analyzed, 0 Elsevier, Paris 1
Kervalishvili, N A
2015-01-01T23:59:59.000Z
The results of experimental investigations of inhomogeneities of gas-discharge nonneutral electron plasma obtained by using the nonperturbing experimental methods [N.A. Kervalishvili, arXiv:1502.02516 [physics.plasm-ph] (2015)] have been presented. Inhomogeneities are the dense solitary vortex structures stretched along the magnetic field, the lifetime of which is much greater than the time of electron-neutral collisions. The processes of formation, evolution and dynamics of vortex structures were studied. The periodic sequence of these processes is described for different geometries of discharge device.
Vortex phase-jitter in acoustically excited bluff body flames
Lieuwen, Timothy C.
Vortex phase-jitter in acoustically excited bluff body flames Santosh J. Shanbhogue, Michael disturbances. Phase locked particle image velocimetry was carried out over a range of conditions", manifested as cycle-to-cycle variation in flame and vorticity field at the same excitation phase. Phase
Onset of superradiant instabilities in the hydrodynamic vortex model
Shahar Hod
2014-07-30T23:59:59.000Z
The hydrodynamic vortex, an effective spacetime geometry for propagating sound waves, is studied analytically. In contrast with the familiar Kerr black-hole spacetime, the hydrodynamic vortex model is described by an effective acoustic geometry which has no horizons. However, this acoustic spacetime possesses an ergoregion, a property which it shares with the rotating Kerr spacetime. It has recently been shown numerically that this physical system is linearly unstable due to the superradiant scattering of sound waves in the ergoregion of the effective spacetime. In the present study we use analytical tools in order to explore the onset of these superradiant instabilities which characterize the effective spacetime geometry. In particular, we derive a simple analytical formula which describes the physical properties of the hydrodynamic vortex system in its critical (marginally-stable) state, the state which marks the boundary between stable and unstable fluid configurations. The analytically derived formula is shown to agree with the recently published numerical data for the hydrodynamic vortex system.
AXISYMMETRIC VORTEX BREAKDOWN IN AN ENCLOSED CYLINDER FLOW.
Lopez, John M.
into the interior flow from the Ekman boundary layer on the rotating endwall is observed, as is the formation,. The boundary conditions are also defined precisely since the flow is confined in a fixed volume. As Re and and the flow remains oscillatory. This oscillatory behavior is mostly confined to the central vortex region. 2
Modified Black Hole with Polar Jet and Vortex
T. Tmmalm
2001-12-06T23:59:59.000Z
There are many models relating an accretion disk of Black Hole to jet outflow. The herein heuristic model describes the continuation of an external accretion disk to an internal accretion disk for less than Black Hole horizon, and subsequent polar jet outflow along polar axis out of polar vortex wherein the event horizon is no longer descriptive.
Creation and pinning of vortex-antivortex pairs
Kim, Sangbum; Hu, Chia-Ren; Andrews, Malcolm J.
2006-01-01T23:59:59.000Z
Computer modeling is reported about the creation and pinning of a magnetic vortex-antivortex (V-AV) pair in a superconducting thin film, due to the magnetic field of a vertical magnetic dipole above the film, and two antidot pins inside the film...
-STABILITY AND VORTEX MOTION IN TYPE II SUPERCONDUCTORS
Spirn, Daniel
-STABILITY AND VORTEX MOTION IN TYPE II SUPERCONDUCTORS MATTHIAS KURZKE AND DANIEL SPIRN Abstract. 1. Introduction 1.1. Physical background. The evolution of a superconducting material is usu- ally of the magnetic field and the electric field potential for a superconducting sample R2 . The parameter
LINEAR DISPERSIVE DECAY ESTIMATES FOR VORTEX SHEETS WITH SURFACE TENSION
Spirn, Daniel
governing irrotational vortex sheets and water waves with surface tension. Using oscillatory integral order, well- posedness theory poses difficulties; however, local-in-time existence for water waves by the kinematic condition in that the interface does not break. This implies the component of the velocity field
Vortex Shedding on Hydrofoils Its dark and lonely down there...
Vortex Shedding on Hydrofoils Its dark and lonely down there... Improving marine vehicle an underwater vehicle moves, it displaces water, genera6ng a unique velocity that it can u6lize rather than fight those flows, saving energy and improving
Vortex stabilized electron beam compressed fusion grade plasma
Hershcovitch, Ady [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.
2014-03-19T23:59:59.000Z
Most inertial confinement fusion schemes are comprised of highly compressed dense plasmas. Those schemes involve short, extremely high power, short pulses of beams (lasers, particles) applied to lower density plasmas or solid pellets. An alternative approach could be to shoot an intense electron beam through very dense, atmospheric pressure, vortex stabilized plasma.
Inhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates
Correggi, Michele
2012-01-01T23:59:59.000Z
We consider a 2D rotating Bose gas described by the Gross-Pitaevskii (GP) theory and investigate the properties of the ground state of the theory for rotational speeds close to the critical speed for vortex nucleation. While one could expect that the vortex distribution should be homogeneous within the condensate we prove by means of an asymptotic analysis in the strongly interacting (Thomas-Fermi) regime that it is not. More precisely we rigorously derive a formula due to Sheehy and Radzihovsky [Phys. Rev. A 70, 063620(R) (2004)] for the vortex distribution, a consequence of which is that the vortex distribution is strongly inhomogeneous close to the critical speed and gradually homogeneizes when the rotation speed is increased. From the mathematical point of view, a novelty of our approach is that we do not use any compactness argument in the proof, but instead provide explicit estimates on the difference between the vorticity measure of the GP ground state and the minimizer of a certain renormalized energy...
Inhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates
Paris-Sud XI, UniversitÃ© de
be homogeneous within the condensate we prove by means of an asymptotic analysis in the strongly interactingInhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates M. Correggia , N. Rougerieb, France. May 10, 2012 Abstract We consider a 2D rotating Bose gas described by the Gross-Pitaevskii (GP
Inhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates
Paris-Sud XI, UniversitÃ© de
should be homogeneous within the condensate we prove by means of an asymptotic analysis in the stronglyInhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates M. Correggia , N. Rougerieb, France. September 19, 2012 Abstract We consider a 2D rotating Bose gas described by the Gross
Spacetime Defects: von Kármán vortex street like configurations
Patricio S. Letelier
2001-07-05T23:59:59.000Z
A special arrangement of spinning strings with dislocations similar to a von K\\'arm\\'an vortex street is studied. We numerically solve the geodesic equations for the special case of a test particle moving along twoinfinite rows of pure dislocations and also discuss the case of pure spinning defects.
Shape of Lambda hypernuclei in (beta,gamma) deformation plane
Myaing Thi Win; K. Hagino; T. Koike
2010-12-15T23:59:59.000Z
We study the shape of $\\Lambda$ hypernuclei in the full ($\\beta,\\gamma$) deformation plane, including both axially symmetric and triaxial quadrupole deformations. To this end, we use the constrained Skyrme Hartree-Fock+BCS method on the three-dimensional Cartesian mesh. The potential energy surface is analyzed for carbon hypernuclei as well as for sd-shell hypernuclei such as $^{27,29}_{\\Lambda}$Si and $^{25,27}_{\\Lambda}$Mg. We show that the potential energy surface in the ($\\beta,\\gamma$) plane is similar to each other between the hypernuclei and the corresponding core nuclei, although the addition of $\\Lambda$ hyperon makes the energy surface somewhat softer along the $\\gamma$ direction. Our calculation implies that the energy of the $\\gamma$ vibration for $^{25,27}_{\\Lambda}$Mg nuclei is lowered by about 0.15 MeV with respect to that of $^{24,26}$Mg nuclei.
Earth's Inner Core dynamics induced by the Lorentz force
Lasbleis, M; Cardin, P; Labrosse, S
2015-01-01T23:59:59.000Z
Seismic studies indicate that the Earth's inner core has a complex structure and exhibits a strong elastic anisotropy with a cylindrical symmetry. Among the various models which have been proposed to explain this anisotropy, one class of models considers the effect of the Lorentz force associated with the magnetic field diffused within the inner core. In this paper we extend previous studies and use analytical calculations and numerical simulations to predict the geometry and strength of the flow induced by the poloidal component of the Lorentz force in a neutrally or stably stratified growing inner core, exploring also the effect of different types of boundary conditions at the inner core boundary (ICB). Unlike previous studies, we show that the boundary condition that is most likely to produce a significant deformation and seismic anisotropy is impermeable, with negligible radial flow through the boundary. Exact analytical solutions are found in the case of a negligible effect of buoyancy forces in the inne...
Semi-microscopic description of the double backbending in some deformed even-even rare earth nuclei
R. Budaca; A. A. Raduta
2013-01-25T23:59:59.000Z
A semi-microscopic model to study the neutron and proton induced backbending phenomena in some deformed even-even nuclei from the rare earth region, is proposed. The space of particle-core states is defined by the angular momentum projection of a quadrupole deformed product state. The backbending phenomena are described by mixing four rotational bands, defined by a set of angular momentum projected states, and a model Hamiltonian describing a set of paired particles moving in a deformed mean field and interacting with a phenomenological deformed core. The ground band corresponds to the configuration where all particles are paired while the other rotational bands are built on one neutron or/and one proton broken pair. Four rare earth even-even nuclei which present the second anomaly in the observed moments of inertia are successfully treated within the proposed model.
Secure Core Contact Information
Secure Core Contact Information C. E. Irvine irvine@nps.edu 831-656-2461 Department of Computer for the secure management of local and/or remote information in multiple contexts. The SecureCore project Science Graduate School of Operations and Information Sciences www.cisr.nps.edu Project Description
Analysis on q-deformed quantum spaces
Hartmut Wachter
2006-04-13T23:59:59.000Z
A q-deformed version of classical analysis is given to quantum spaces of physical importance, i.e. Manin plane, q-deformed Euclidean space in three or four dimensions, and q-deformed Minkowski space. The subject is presented in a rather complete and selfcontained way. All relevant notions are introduced and explained in detail. The different possibilities to realize the objects of q-deformed analysis are discussed and their elementary properties are studied. In this manner attention is focused on star products, q-deformed tensor products, q-deformed translations, q-deformed partial derivatives, dual pairings, q-deformed exponentials, and q-deformed integration. The main concern of this work is to show that these objects fit together in a consistent framework, which is suitable to formulate physical theories on quantum spaces.
Pressurized water nuclear reactor system with hot leg vortex mitigator
Lau, Louis K. S. (Monroeville, PA)
1990-01-01T23:59:59.000Z
A pressurized water nuclear reactor system includes a vortex mitigator in the form of a cylindrical conduit between the hot leg conduit and a first section of residual heat removal conduit, which conduit leads to a pump and a second section of residual heat removal conduit leading back to the reactor pressure vessel. The cylindrical conduit is of such a size that where the hot leg has an inner diameter D.sub.1, the first section has an inner diameter D.sub.2, and the cylindrical conduit or step nozzle has a length L and an inner diameter of D.sub.3 ; D.sub.3 /D.sub.1 is at least 0.55, D.sub.2 is at least 1.9, and L/D.sub.3 is at least 1.44, whereby cavitation of the pump by a vortex formed in the hot leg is prevented.
Vortex energy and 360 Neel walls in thinfilm
.Ignat@math.u-psud.fr) Courant Institute, New York University, New York, NY 10012, USA (e-mail: knuepfer@cims.nyu.edu) 1 #12Vortex energy and 360 N´eel walls in thinfilm micromagnetics Radu Ignat , Hans Kn¨upfer October-section. The model is based on the following energy functional: E2d (m) = Z B2 |m|2 dx + | ln | 2 Z R2 ||-1
Vortex topology and the continuum limit of lattice gauge theories
G. Burgio
2007-10-02T23:59:59.000Z
We study the stability of Z_2 topological vortex excitations in d+1 dimensional SU(2) Yang-Mills theory on the lattice at T=0. This is found to depend on d and on the coupling considered. We discuss the connection with lattice artifacts causing bulk transitions in the beta_A-beta_F plane and draw some conclusions regarding the continuum limit of the theory.
Reduction of the planar 4-vortex system at zero momentum
Patrick, George
in the plane the nth vortex has location zn = xn + iyn Ppl (C2 )N . The Hamiltonian and symplectic form- nally on each factor C of Ppl by (ei , a) Â· z ei z + a. A momentum mapping is Jpl - N n=1 n 1 2 |zn|2]. To calculate the quotient Âµe : (Jpl )-1 (Âµe) (Ppl )Âµe (Jpl )-1 (Âµe)/SE(2), one may first translate
Vortex energy and 360 Neel wall in thinfilm
Ignat, Radu
.Ignat@math.u-psud.fr) Courant Institute, New York University, New York, NY 10012, USA (e-mail: knuepfer@cims.nyu.edu) 1 #12Vortex energy and 360 N´eel wall in thinfilm micromagnetics Radu Ignat , Hans Kn¨upfer October-section. The model is based on the following energy functional: E2d (m) = Z B2 |m|2 dx + | ln | 2 Z R2 ||-1
High-precision calculations of vortex sheet motion
Ely, J.S. (Lewis and Clark College, Portland, OR (United States)); Baker, G.R. (Ohio State Univ., Columbus, OH (United States))
1994-04-01T23:59:59.000Z
The motion of a vortex sheet undergoing Kelvin-Helmholtz instability is known to be ill-posed, causing deterioration in numerical calculations from the rapid growth of round-off errors. In particular, it is the smallest scales (introduced by round-off) that grow the fastest. Krasny introduced a spectral filter to suppress the growth of round-off errors of the smallest scales. He was then able to detect evidence supporting asymptotic studies that indicate the formation of a curvature singularity in finite time. We use high precision interval arithmetic, coded in C + +, to re-examine the evolution of a vortex sheet from initial conditions used previously by several researchers. Most importantly, our results are free from the influence of round-off errors. We show excellent agreement between results obtained through high precision interval arithmetic and through the use of Krasny's spectral filter. In particular, our results support the formation of a curvature singularity in finite time. After the time of singularity formation, the markers move in peculiar patterns. We rule out any possibility of this motion resulting from round-off errors, but it does depend on the level of resolution. We find no consistent behavior in the motion of the markers as we improve the resolution of the vortex sheet. Also, we find some disagreement between the results obtained through high precision interval arithmetic and through the use of the spectral filter. 29 refs., 5 figs.
Gilmore, Charles B.; Forsyth, David R.
2013-09-10T23:59:59.000Z
A core shroud is provided, which includes a number of planar members, a number of unitary corners, and a number of subassemblies each comprising a combination of the planar members and the unitary corners. Each unitary corner comprises a unitary extrusion including a first planar portion and a second planar portion disposed perpendicularly with respect to the first planar portion. At least one of the subassemblies comprises a plurality of the unitary corners disposed side-by-side in an alternating opposing relationship. A plurality of the subassemblies can be combined to form a quarter perimeter segment of the core shroud. Four quarter perimeter segments join together to form the core shroud.
Tyler, Noel
2000-08-14T23:59:59.000Z
This report summarizes activities for the repository during this quarter. The repository holds drill cores and cuttings samples from oil wells that can be viewed or checked out by users.
Is inner core seismic anisotropy a marker of plastic flow of cubic iron?
Lincot, A; Cardin, Philippe
2015-01-01T23:59:59.000Z
This paper investigates whether observations of seismic anisotropy are compatible with a cubic structure of the inner core Fe alloy. We assume that anisotropy is the result of plastic deformation within a large scale flow induced by preferred growth at the inner core equator. Based on elastic moduli from the literature, bcc- or fcc-Fe produce seismic anisotropy well below seismic observations ($\\textless{}0.4\\%$). A Monte-Carlo approach allows us to generalize this result to any form of elastic anisotropy in a cubic system. Within our model, inner core global anisotropy is not compatible with a cubic structure of Fe alloy. Hence, if the inner core material is indeed cubic, large scale coherent anisotropic structures, incompatible with plastic deformation induced by large scale flow, must be present.
Schenewerk, William E. (Sherman Oaks, CA); Glasgow, Lyle E. (Westlake Village, CA)
1983-01-01T23:59:59.000Z
A liquid metal cooled fast breeder reactor provided with an emergency core cooling system includes a reactor vessel which contains a reactor core comprising an array of fuel assemblies and a plurality of blanket assemblies. The reactor core is immersed in a pool of liquid metal coolant. The reactor also includes a primary coolant system comprising a pump and conduits for circulating liquid metal coolant to the reactor core and through the fuel and blanket assemblies of the core. A converging-diverging venturi nozzle with an intermediate throat section is provided in between the assemblies and the pump. The intermediate throat section of the nozzle is provided with at least one opening which is in fluid communication with the pool of liquid sodium. In normal operation, coolant flows from the pump through the nozzle to the assemblies with very little fluid flowing through the opening in the throat. However, when the pump is not running, residual heat in the core causes fluid from the pool to flow through the opening in the throat of the nozzle and outwardly through the nozzle to the assemblies, thus providing a means of removing decay heat.
Fischer, Noah A. [Los Alamos National Laboratory
2012-08-14T23:59:59.000Z
The reactor core input generator allows for MCNP input files to be tailored to design specifications and generated in seconds. Full reactor models can now easily be created by specifying a small set of parameters and generating an MCNP input for a full reactor core. Axial zoning of the core will allow for density variation in the fuel and moderator, with pin-by-pin fidelity, so that BWR cores can more accurately be modeled. LWR core work in progress: (1) Reflectivity option for specifying 1/4, 1/2, or full core simulation; (2) Axial zoning for moderator densities that vary with height; (3) Generating multiple types of assemblies for different fuel enrichments; and (4) Parameters for specifying BWR box walls. Fuel pin work in progress: (1) Radial and azimuthal zoning for generating further unique materials in fuel rods; (2) Options for specifying different types of fuel for MOX or multiple burn assemblies; (3) Additional options for replacing fuel rods with burnable poison rods; and (4) Control rod/blade modeling.
Core Values | Department of Energy
Broader source: Energy.gov (indexed) [DOE]
Core Values Core Values People - People are our most important resource. We respect and use our experience and skills and appreciate our diversity. Business Excellence - We are...
Finite Deformation of Materials with an Ensemble of Defects
J.K. Dienes
2003-01-01T23:59:59.000Z
The theory of large deformations developed here is closely related to continuum mechanics but it differs in several major respects, especially in considering the deformation associated with various types of physical behavior, making it possible to synthesize a general approach to formulating constitutive laws. One goal is to derive general concepts of strain, strain rate, stress, and stress rate that are somewhat more physics-based than in most standard works on continuum mechanics, and to demonstrate some new relations between these quantities. With these concepts it is possible to develop a generalized principle of superposition of strain rates (GSSR) that accounts for damage as well as plastic flow. The traditional superposition of strain rates allows for addition of elastic and plastic strain rates and is commonly thought to be valid only for small strains. The GSSR allows us to compute deformations involving plastic flow and, in addition, brittle failure, fragmentation, high-pressure effects and other types of behavior as necessary, and the theory is valid for arbitrarily large deformations. In fact, GSSR is derived from more basic ideas and has broader application than the standard superposition of strain rates. The physical basis for calculations of complex material response is developed in a separate report. The implementation into the SCRAM computer program is documented separately. The polar decomposition theorem is taken as a starting point for the theory of large deformation, an approach somewhat different from that usually taken in continuum mechanics. Two sets of orthogonal axes are distinguished, space axes that are fixed in ambient space, and polar axes that are related to material deformation. This clarifies several concepts; for example, it is shown that the Signorini and Green-St. Venant strains are actually measures of the same physical entity, one in space axes and the other in polar axes. It follows that they are not competing measures, as is often implied in traditional continuum mechanics. It also follows that Piola stress is a measure in polar axes, while Cauchy stress is a measure in space axes. Another consequence of polar decomposition is a proof that vorticity is not a measure of the rate of material rotation (as is often stated in the hydrodynamics literature) but that they are related. This allows us to develop an exact approach to computing rates of tensor quantities, called polar rates, that account for material rotation in an exact way. This leads to a simple relation between Signorini strain rate and stretching (the symmetric part of the velocity gradient). It also follows that the polar stress rate is the appropriate measure for the rate of change of Cauchy stress, and that the more traditional stress rate of Zaremba, Jaumann, and Noll is only an approximation, valid at small strains. Examples are described for materials undergoing simple shear, vortex motion, and torsion.
Vortex-induced vibration of a circular cylinder with combined in-line and cross-flow motion
Dahl, Jason (Jason Michael)
2008-01-01T23:59:59.000Z
Deep water, string-like, marine risers subject to strong ocean currents, suffer from vortex-induced vibrations (VIV), where vortex shedding interacts with the structural properties of the riser, resulting in large amplitude ...
Quantum mechanical effects from deformation theory
Much, A. [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig, Germany and Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)] [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig, Germany and Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)
2014-02-15T23:59:59.000Z
We consider deformations of quantum mechanical operators by using the novel construction tool of warped convolutions. The deformation enables us to obtain several quantum mechanical effects where electromagnetic and gravitomagnetic fields play a role. Furthermore, a quantum plane can be defined by using the deformation techniques. This in turn gives an experimentally verifiable effect.
CubeSat deformable mirror demonstration
Cahoy, Kerri
The goal of the CubeSat Deformable Mirror Demonstration (DeMi) is to characterize the performance of a small deformable mirror over a year in low-Earth orbit. Small form factor deformable mirrors are a key technology needed ...
Deformation mechanisms of experimentally deformed Salina Basin bedded salt
Hansen, F.D.
1985-01-01T23:59:59.000Z
Petrofabrics of deformed salt from the Cleveland area within the Salina Basin are presented. Quasi-static compression at room temperature and 1 MPa confining pressure is dominated by fracture. Incipient failure is evidenced by wide zones of coalesced fractures at an axial strain of 5%. Strain hardening, evidenced by photoelastic effects, abounds under these conditions. At 5 MPa far fewer fractures are found at axial strains of 13%. Photoelastic effects are appreciably diminished at 5 MPa, which must mean more homogeneous ductile flow ensues, perhaps owing to activation of many dislocation mills. Clearly, the brittle-to-ductile transition requires additional petrographic work for documentation. Because the dominant mechanism is very pressure sensitive at relative low mean stresses, it appears necessary to include confining pressure in the deformation mechanism map. Creep at 15 MPa and temperatures >100/sup 0/C is dominated by thermally activated diffusion. Fracture and photoelastic effects are almost totally suppressed relative to quasi-static experiments at lower confining pressure and temperature. The mechanism of climb into stable polygons is fully documented by etch pit studies in samples that are deformed well into steady state. Creep properties of Cleveland and Avery Island salt are very similar under conditions of elevated temperature and intermediate stresses. As temperature is reduced the predicted flow stress of Cleveland becomes greater than that of Avery Island. However, extrapolation of either flow law to low temperature is not justified because the governing mechanisms change from climb to fracture and glide.
A model for universal time scale of vortex ring formation Kamran Mohseni
Mohseni, Kamran
and Applied Science, 104-44, California Institute of Technology, Pasadena, California 91125 Morteza Gharib Graduate Aeronautical Laboratory, California Institute of Technology, Pasadena, California 91125 Received of the fluid out of the cylinder and the approximation of the vortex at the pinch off moment by a vortex
Combustion in Meso-scale Vortex Chambers Ming-hsun Wu*
Yang, Vigor
1 Combustion in Meso-scale Vortex Chambers Ming-hsun Wu* , Yanxing Wang, Vigor Yang and Richard A) #12;2 COMBUSTION IN MESO-SCALE VORTEX CHAMBERS Ming-hsun Wu, Yanxing Wang, Vigor Yang and Richard A with the chemical energy varying from 25 to 174W. For the largest combustion volume, hydrogen and hydrocarbons
The geometric phase and the geometrodynamics of relativistic electron vortex beams
Pratul Bandyopadhyay; Banasri Basu; Debashree Chowdhury
2013-11-28T23:59:59.000Z
We have studied here the geometrodynamics of relativistic electron vortex beams from the perspective of the geometric phase associated with the scalar electron encircling the vortex line. It is pointed out that the electron vortex beam carrying orbital angular momentum is a natural consequence of the skyrmion model of a fermion. This follows from the quantization procedure of a fermion in the framework of Nelson's stochastic mechanics when a direction vector (vortex line) is introduced to depict the spin degrees of freedom. In this formalism a fermion is depicted as a scalar particle encircling a vortex line. It is here shown that when the Berry phase acquired by the scalar electron encircling the vortex line involves quantized Dirac monopole we have paraxial (non-paraxial) beam when the vortex line is parallel (orthogonal) to the wavefront propagation direction. Non-paraxial beams incorporate spin-orbit interaction. When the vortex line is tilted with respect to the propagation direction the Berry phase involves non-quantized monopole. The temporal variation of the direction of the tilted vortices is studied here taking into account the renormalization group flow of the monopole charge and it is predicted that this gives rise to spin Hall effect.
Determination of magnetic vortex chirality using lateral spin-valve and Y. Otani
Otani, Yoshichika
Determination of magnetic vortex chirality using lateral spin-valve geometry T. Kimuraa and Y October 2005 We demonstrate the determination of the vortex chirality using a nonlocal spin-valve measurement technique in a lateral spin valve consisting of a Permalloy Py disk 1 m in diameter and a Py wire
PHYSICAL REVIEW B 84, 144511 (2011) Rectification of vortex motion in a circular ratchet channel
Plourde, Britton L. T.
2011-01-01T23:59:59.000Z
PHYSICAL REVIEW B 84, 144511 (2011) Rectification of vortex motion in a circular ratchet channel N and induces a net vortex flow without any unbiased external drive, i.e., the ratchet effect. We show containing a single weak-pinning circular ratchet channel in a Corbino geometry and observed a substantial
Generalized London free energy for high-Tc vortex lattices Ian Affleck
Franz, Marcel
Generalized London free energy for high-Tc vortex lattices Ian Affleck Department of Physics-1829 97 50402-4 The London free energy provides a very simple way of studying the vortex lattice that this effect can arise from additional quartic derivative terms in the Ginzburg-Landau GL free energy47 or
FABRICATION ET TUDE D'UN MONOCRISTAL DE VORTEX DANS LE NIOBIUM SUPRACONDUCTEUR
Paris-Sud XI, Université de
447 FABRICATION ET ÉTUDE D'UN MONOCRISTAL DE VORTEX DANS LE NIOBIUM SUPRACONDUCTEUR P. THOREL. 2014 Nous étudions expérimentalement par diffraction de neutrons le réseau de vortex dans le niobium ce V-cristal est liée à celle des axes cristallins du niobium, étant donné la forte anisotropie des
GPU accelerated simulations of bluff body flows using vortex particle methods
Cottet, Georges-Henri
GPU accelerated simulations of bluff body flows using vortex particle methods Diego Rossinelli in press as: D. Rossinelli et al., GPU accelerated simulations of bluff body flows using vortex particle Penalization Bluff body flows a b s t r a c t We present a GPU accelerated solver for simulations of bluff body
Wei, John Y.T.
Lateral imaging of the superconducting vortex lattice using Doppler-modulated scanning tunneling on the quasiparticle tunneling spectrum, we have laterally imaged the vortex lattice in superconducting 2H-NbSe2 that circulates along the sample edge. Above the lower critical field, field can penetrate into the superconductor
Zero modes in vortex-fermion system with compact extra space
A. Nakamula; K. Shiraishi
2014-10-28T23:59:59.000Z
The existence of fermionic zero modes is shown in the presence of vortex configuration of pure $SU(2)$ gauge field on the manifold $M_4 \\times S^2$. From the perspective of four-dimensional effective theory, these zero modes are almost the same as the Jackiw-Rossi type zero modes of the vortex-fermion system.
Efficiently computing vortex lattices in fast rotating Bose-Einstein condensates Yanzhi Zhang1,2
Bao, Weizhu
Efficiently computing vortex lattices in fast rotating Bose-Einstein condensates Yanzhi Zhang1-Einstein condensates (BECs) with strongly repulsive interactions. The key ingredients of the method is to discretize method in time. Different vortex lattice structures of condensate ground state in two-dimensional (2D
Progress in year 2001 1. Observation of Vortex Lattices in Bose-Einstein Condensates
1 Progress in year 2001 1. Observation of Vortex Lattices in Bose-Einstein Condensates Quantized in rotating gaseous Bose-Einstein condensates (BEC) [2, 3]. We have observed the formation of highly-ordered vortex lattices in a rotating Bose- condensed gas [4]. They were produced by rotating the condensate
Influence of slip on vortex-induced motion of a superhydrophobic cylinder
Rothstein, Jonathan
Influence of slip on vortex-induced motion of a superhydrophobic cylinder Robert Daniello, Pranesh: Superhydrophobic Ultrahydrophobic Superhydrophobicity Slip Partial slip Drag reduction Vortex Cylinder a b s t r a c t The partial slip boundary condition produced by a superhydrophobic surface in the Cassie state
Elliptical-inertial instability of rotating Karman vortex streets A. Stegnera
Stegner Alexandre
Elliptical-inertial instability of rotating Karman vortex streets A. Stegnera Laboratoire de. Unlike the classical bidimensional Karman street, these observed vortex streets are affected by the earth Karman streets. A series of experiments were performed to study the wake of a cylinder in a rotating deep
Vortex ratchet effects in films with a periodic array of antidots Clcio C. de Souza Silva,1,
Moshchalkov, Victor V.
Vortex ratchet effects in films with a periodic array of antidots Clécio C. de Souza Silva,1, * J The vortex ratchet effect has been studied in Al films patterned with square arrays of submicron antidots. We. In addition, the experiments reveal interesting collective phenomena in the vortex ratchet effect. At fields
Hu, Hui
flapping motion is due to the reverse von Karman vortex street. Recently, Bohl and Koochesfahani1 haveAmerican Institute of Aeronautics and Astronautics 1 A Numerical Study of Vortex-Dominated Flow at the Reynolds (Re) number of 12600. The effects of the reduced frequency and Strouhal number on the wake vortex
Bluff Body Flow Simulation Using a Vortex Element Method
Anthony Leonard; Phillippe Chatelain; Michael Rebel
2004-09-30T23:59:59.000Z
Heavy ground vehicles, especially those involved in long-haul freight transportation, consume a significant part of our nation's energy supply. it is therefore of utmost importance to improve their efficiency, both to reduce emissions and to decrease reliance on imported oil. At highway speeds, more than half of the power consumed by a typical semi truck goes into overcoming aerodynamic drag, a fraction which increases with speed and crosswind. Thanks to better tools and increased awareness, recent years have seen substantial aerodynamic improvements by the truck industry, such as tractor/trailer height matching, radiator area reduction, and swept fairings. However, there remains substantial room for improvement as understanding of turbulent fluid dynamics grows. The group's research effort focused on vortex particle methods, a novel approach for computational fluid dynamics (CFD). Where common CFD methods solve or model the Navier-Stokes equations on a grid which stretches from the truck surface outward, vortex particle methods solve the vorticity equation on a Lagrangian basis of smooth particles and do not require a grid. They worked to advance the state of the art in vortex particle methods, improving their ability to handle the complicated, high Reynolds number flow around heavy vehicles. Specific challenges that they have addressed include finding strategies to accurate capture vorticity generation and resultant forces at the truck wall, handling the aerodynamics of spinning bodies such as tires, application of the method to the GTS model, computation time reduction through improved integration methods, a closest point transform for particle method in complex geometrics, and work on large eddy simulation (LES) turbulence modeling.
Vortex nozzle for segmenting and transporting metal chips from turning operations
Bieg, L.F.
1993-04-20T23:59:59.000Z
Apparatus for collecting, segmenting and conveying metal chips from machining operations utilizes a compressed gas driven vortex nozzle for receiving the chip and twisting it to cause the chip to segment through the application of torsional forces to the chip. The vortex nozzle is open ended and generally tubular in shape with a converging inlet end, a constant diameter throat section and a diverging exhaust end. Compressed gas is discharged through angled vortex ports in the nozzle throat section to create vortex flow in the nozzle and through an annular inlet at the entrance to the converging inlet end to create suction at the nozzle inlet and cause ambient air to enter the nozzle. The vortex flow in the nozzle causes the metal chip to segment and the segments thus formed to pass out of the discharge end of the nozzle where they are collected, cleaned and compacted as needed.
$?$-Deformed Statistics and Classical Fourmomentum Addition Law
M. Daszkiewicz; J. Lukierski; M. Woronowicz
2008-02-05T23:59:59.000Z
We consider $\\kappa$-deformed relativistic symmetries described algebraically by modified Majid-Ruegg bicrossproduct basis and investigate the quantization of field oscillators for the $\\kappa$-deformed free scalar fields on $\\kappa$-Minkowski space. By modification of standard multiplication rule, we postulate the $\\kappa$-deformed algebra of bosonic creation and annihilation operators. Our algebra permits to define the n-particle states with classical addition law for the fourmomenta in a way which is not in contradiction with the nonsymmetric quantum fourmomentum coproduct. We introduce $\\kappa$-deformed Fock space generated by our $\\kappa$-deformed oscillators which satisfy the standard algebraic relations with modified $\\kappa$-multiplication rule. We show that such a $\\kappa$-deformed bosonic Fock space is endowed with the conventional bosonic symmetry properties. Finally we discuss the role of $\\kappa$-deformed algebra of oscillators in field-theoretic noncommutative framework.
The Relation Between Dry Vortex Merger and Tropical Cyclone Genesis over the Atlantic Ocean
Chen, Shu-Hua; Liu, Yi-Chin
2014-10-27T23:59:59.000Z
A strong, convective African tropical disturbance has a greater chance to develop into a Tropical 23 Depression (TD) if it merges with a shallow, dry vortex (D-vortex) from the north of the African 24 easterly jet (AEJ) after leaving the western coast. Using 11-year reanalysis data we found that the 25 western tip of a vortex strip at northwestern Africa can serve as dry vortices for the D-vortex 26 merger if it shifts southward. Another source of D-vortices is the westward propagating lows 27 along the southern edge of the Saharan air. The D-vortex merger process occurred for 63.5% of 28 tropical cyclones (TCs) or developing systems over the main development region of the Atlantic 29 Ocean, while it occurred for 54% of non-developing systems. TC genesis could be largely 30 controlled by the large-scale environment, but the differences in characteristics of vortices 31 associated with the D-vortex merger between developing and non-developing systems could 32 potentially help determine their destinies; in general, developing systems were dominated by a 33 more intense and moist south vortex, while non-developing systems were dominated by a north 34 vortex which was more intense, drier, and larger in size. Analysis also shows that 74% of intense 35 developing systems were involved with the D-vortex merger process. More attention needs to be 36 paid to the D-vortex merger and the characteristics of those vortices as they can play significant 37 roles or have a strong indication in Atlantic TC genesis.
Electromagnetic pump stator core
Fanning, Alan W. (San Jose, CA); Olich, Eugene E. (Aptos, CA); Dahl, Leslie R. (Livermore, CA)
1995-01-01T23:59:59.000Z
A stator core for supporting an electrical coil includes a plurality of groups of circumferentially abutting flat laminations which collectively form a bore and perimeter. A plurality of wedges are interposed between the groups, with each wedge having an inner edge and a thicker outer edge. The wedge outer edges abut adjacent ones of the groups to provide a continuous path around the perimeter.
Quantum limits to estimation of photon deformation
Giovanni De Cillis; Matteo G. A. Paris
2014-07-08T23:59:59.000Z
We address potential deviations of radiation field from the bosonic behaviour and employ local quantum estimation theory to evaluate the ultimate bounds to precision in the estimation of these deviations using quantum-limited measurements on optical signals. We consider different classes of boson deformation and found that intensity measurement on coherent or thermal states would be suitable for their detection making, at least in principle, tests of boson deformation feasible with current quantum optical technology. On the other hand, we found that the quantum signal-to-noise ratio (QSNR) is vanishing with the deformation itself for all the considered classes of deformations and probe signals, thus making any estimation procedure of photon deformation inherently inefficient. A partial way out is provided by the polynomial dependence of the QSNR on the average number of photon, which suggests that, in principle, it would be possible to detect deformation by intensity measurements on high-energy thermal states.
Kelemen, Peter
2012-08-24T23:59:59.000Z
Topics covered include: Failure At High Confining Pressure; Fluid-assisted Slip, Earthquakes & Fracture; Reaction-driven Cracking; Fluid Transport, Deformation And Reaction; Localized Fluid Transport And Deformation; Earthquake Mechanisms; Subduction Zone Dynamics And Crustal Growth.
Deformation-Twin-Induced Grain Boundary Failure
Yongfeng Zhang; Paul C. MIllett; Michael Tonks; Bulent Biner
2012-01-01T23:59:59.000Z
This work presents a mechanism of deformation-twin-induced grain boundary failure, and demonstrates the mechanism using molecular dynamics simulations. Deformation twinning is observed as the dominant mechanism during tensile deformation of columnar nanocrystalline body-centered cubic Mo. As a twin approaches a grain boundary, local stress concentration develops due to the incompatible plastic deformations in the two neighboring grains. The magnitude of the stress concentration increases as the twin widens, leading to grain boundary cracking by nucleation and coalescence of microcracks/voids.
Magnetic response of holographic Lifshitz superconductors:Vortex and Droplet solutions
Arindam Lala
2014-07-04T23:59:59.000Z
In this paper a holographic model of $s$-wave superconductor with anisotropic Lifshitz scaling has been considered. In the presence of an external magnetic field our holographic model exhibits both vortex and droplet solutions. Based on analytic methods we have shown that the anisotropy has no effect on the vortex and droplet solutions whereas it may affect the condensation. Our vortex solution closely resembles the Ginzburg-Landau theory and a relation between the upper critical magnetic field and superconducting coherence length has been speculated from this comparison. Using Sturm-Liouville method, the effect of anisotropy on the critical parameters in insulator/superconductor phase transitions has been analyzed.
Banded electromagnetic stator core
Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.
1994-04-05T23:59:59.000Z
A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.
Electromagnetic pump stator core
Fanning, A.W.; Olich, E.E.; Dahl, L.R.
1995-01-17T23:59:59.000Z
A stator core for supporting an electrical coil includes a plurality of groups of circumferentially abutting flat laminations which collectively form a bore and perimeter. A plurality of wedges are interposed between the groups, with each wedge having an inner edge and a thicker outer edge. The wedge outer edges abut adjacent ones of the groups to provide a continuous path around the perimeter. 21 figures.
Banded electromagnetic stator core
Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.
1996-06-11T23:59:59.000Z
A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figs.
Bourgeois, P.M.; Reger, R.J.
1996-02-20T23:59:59.000Z
A variable depth core sampler apparatus is described comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member. 7 figs.
Decay of helical Kelvin waves on a quantum vortex filament
Van Gorder, Robert A., E-mail: rav@knights.ucf.edu [Department of Mathematics, University of Central Florida, Orlando, Florida 32816-1364 (United States)
2014-07-15T23:59:59.000Z
We study the dynamics of helical Kelvin waves moving along a quantum vortex filament driven by a normal fluid flow. We employ the vector form of the quantum local induction approximation (LIA) due to Schwarz. For an isolated filament, this is an adequate approximation to the full Hall-Vinen-Bekarevich-Khalatnikov dynamics. The motion of such Kelvin waves is both translational (along the quantum vortex filament) and rotational (in the plane orthogonal to the reference axis). We first present an exact closed form solution for the motion of these Kelvin waves in the case of a constant amplitude helix. Such solutions exist for a critical wave number and correspond exactly to the Donnelly-Glaberson instability, so perturbations of such solutions either decay to line filaments or blow-up. This leads us to consider helical Kelvin waves which decay to line filaments. Unlike in the case of constant amplitude helical solutions, the dynamics are much more complicated for the decaying helical waves, owing to the fact that the rate of decay of the helical perturbations along the vortex filament is not constant in time. We give an analytical and numerical description of the motion of decaying helical Kelvin waves, from which we are able to ascertain the influence of the physical parameters on the decay, translational motion along the filament, and rotational motion, of these waves (all of which depend nonlinearly on time). One interesting finding is that the helical Kelvin waves do not decay uniformly. Rather, such waves decay slowly for small time scales, and more rapidly for large time scales. The rotational and translational velocity of the Kelvin waves depend strongly on this rate of decay, and we find that the speed of propagation of a helical Kelvin wave along a quantum filament is large for small time while the wave asymptotically slows as it decays. The rotational velocity of such Kelvin waves along the filament will increase over time, asymptotically reaching a finite value. These decaying Kelvin waves correspond to wave number below the critical value for the Donnelly-Glaberson instability, and hence our results on the Schwarz quantum LIA correspond exactly to what one would expect from prior work on the Donnelly-Glaberson instability.
Hix, William Raphael [ORNL; Lentz, E. J. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Baird, Mark L [ORNL; Chertkow, Merek A [ORNL; Lee, Ching-Tsai [University of Tennessee, Knoxville (UTK); Blondin, J. M. [North Carolina State University; Bruenn, S. W. [Florida Atlantic University, Boca Raton; Messer, Bronson [ORNL; Mezzacappa, Anthony [ORNL
2013-01-01T23:59:59.000Z
Marking the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae bring together physics at a wide range in spatial scales, from kilometer-sized hydrodynamic motions (growing to gigameter scale) down to femtometer scale nuclear reactions. Carrying 10$^{51}$ ergs of kinetic energy and a rich-mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up ourselves and our solar system. We will discuss our emerging understanding of the convectively unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino-radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Recent multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of how supernovae explode. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.
Gas turbine engine combustor can with trapped vortex cavity
Burrus, David Louis; Joshi, Narendra Digamber; Haynes, Joel Meier; Feitelberg, Alan S.
2005-10-04T23:59:59.000Z
A gas turbine engine combustor can downstream of a pre-mixer has a pre-mixer flowpath therein and circumferentially spaced apart swirling vanes disposed across the pre-mixer flowpath. A primary fuel injector is positioned for injecting fuel into the pre-mixer flowpath. A combustion chamber surrounded by an annular combustor liner disposed in supply flow communication with the pre-mixer. An annular trapped dual vortex cavity located at an upstream end of the combustor liner is defined between an annular aft wall, an annular forward wall, and a circular radially outer wall formed therebetween. A cavity opening at a radially inner end of the cavity is spaced apart from the radially outer wall. Air injection first holes are disposed through the forward wall and air injection second holes are disposed through the aft wall. Fuel injection holes are disposed through at least one of the forward and aft walls.
Spectral Techniques for Solving PDE Stability Model of Vortex Rope
Bistrian, Diana Alina
2012-01-01T23:59:59.000Z
In this paper spectral methods are applied to investigate the hydrodynamic instability of swirling flow with application to Francis hydraulic turbine. Spectral methods imply representing the problem solution as truncated series of smooth global functions. An L2 - projection and the collocation methods are developed assessing both analytically methodology and computational techniques using symbolic and numerical conversions. Remarks concerning the efficiency and the accuracy of each method in this case are presented. The model of the trailing vortex is used to validate the numerical algorithms with existing results in the literature. All the results are compared to existing ones and they prove to agree quite well. The advantages of using this methods in flow control problems are pointed out.
Vortex flow in the technology of radiation wave cracking (RWC)
L. A. Tsoy; V. N. Kolushov; A. G. Komarov; A. N. Tsoy
2012-09-16T23:59:59.000Z
This article examines the theory of vortex flows in relation to the processes occurring in the radiation-wave cracking of crude oil, when the crude oil is sprayed into the gas stream in the form of a mist and then is fed into the reactor, where it is treated by the accelerated electrons and the UHF radiation. The output of this process are the products with the specified parameters (high-octane petroleum products). This process operates at the ambient pressure and temperature, which makes the process safer for industrial purposes. Besides the process itself, the authors described the equipment used in this process, as well as the parameters of the optimal process.
Exact moduli space metrics for hyperbolic vortex polygons
Krusch, S. [School of Mathematics, Statistics and Actuarial Science, University of Kent, Canterbury CT2 7NF (United Kingdom); Speight, J. M. [Department of Pure Mathematics, University of Leeds, Leeds LS2 9JT (United Kingdom)
2010-02-15T23:59:59.000Z
Exact metrics on some totally geodesic submanifolds of the moduli space of static hyperbolic N-vortices are derived. These submanifolds, denoted as {sigma}{sub n,m}, are spaces of C{sub n}-invariant vortex configurations with n single vortices at the vertices of a regular polygon and m=N-n coincident vortices at the polygon's center. The geometric properties of {sigma}{sub n,m} are investigated, and it is found that {sigma}{sub n,n-1} is isometric to the hyperbolic plane of curvature -(3{pi}n){sup -1}. The geodesic flow on {sigma}{sub n,m} and a geometrically natural variant of geodesic flow recently proposed by Collie and Tong ['The dynamics of Chern-Simons vortices', Phys. Rev. D Part. Fields Gravit. Cosmol. 78, 065013 (2008);e-print arXiv:hep-th/0805.0602] are analyzed in detail.
Vortex and gap generation in gauge models of graphene
O. Oliveira; C. E. Cordeiro; A. Delfino; W. de Paula; T. Frederico
2011-04-22T23:59:59.000Z
Effective quantum field theoretical continuum models for graphene are investigated. The models include a complex scalar field and a vector gauge field. Different gauge theories are considered and their gap patterns for the scalar, vector, and fermion excitations are investigated. Different gauge groups lead to different relations between the gaps, which can be used to experimentally distinguish the gauge theories. In this class of models the fermionic gap is a dynamic quantity. The finite-energy vortex solutions of the gauge models have the flux of the "magnetic field" quantized, making the Bohm-Aharonov effect active even when external electromagnetic fields are absent. The flux comes proportional to the scalar field angular momentum quantum number. The zero modes of the Dirac equation show that the gauge models considered here are compatible with fractionalization.
Vortex life cycles in two-and three-layer quasi-geostrophic models
Fox, Amanda Katherine
2000-01-01T23:59:59.000Z
Coherent vortices and their properties were studied in two- and three-layer quasi-geostrophic beta-plane turbulence. Much research has discussed vortex characteristics in a number of applications, but no significant study of vortices in turbulent...
On the vortex parameter estimation using wide band signals in active acoustic system
Paris-Sud XI, Université de
is an important operation in a large number of applications such as turbine monitoring, de- tection of a vortex in a closed hydraulic test loop. The objective of the work is to emphasize the effect
Falling, flapping, flying, swimming,... : high-Re fluid-solid interactions with vortex shedding
Michelin, Sébastien Honoré Roland
2009-01-01T23:59:59.000Z
Meckh. , 1, 79–86. Krasny, R. , 1986a: Desingularisation ofJ. Comp. Phys. , 65, 292–313. Krasny, R. , 1986b: A study ofvortex sheet equation (Krasny, 1986a,b). The vortex sheet
The vortex merger rate in freely decaying, two-dimensional turbulence J. H. LaCascea
LaCasce, Joseph H.
vortex models in which energy-conserving mergers were allowed. Trizac19 used a molecular dynamics in laboratory experiments in which vortices were generated by electromagnetic excitation in an electrolyte.10
A Model of Compressor Blade Row Interaction with Shock Induced Vortex Shedding
Cincinnati, University of
A Model of Compressor Blade Row Interaction with Shock Induced Vortex Shedding Mark G. Turner = circulation = trailing edge thickness = shock angle = density I. Introduction ransonic compressor stages AIAA. Research Scientist, Compressor Aerodynamic Research Laboratory, Associate Fellow AIAA
Kim, S.; Hu, Chia-Ren; Andrews, MJ.
2004-01-01T23:59:59.000Z
that the system passes through nearly metastable intermediate configurations while seeking the final minimum-energy steady state consistent with the square symmetry of the sample. An efficient scheme to determine the equilibrium vortex configuration in a...
Effect of traveling waves on Vortex-Induced Vibration of long flexible cylinders
Jaiswal, Vivek, Ph. D. Massachusetts Institute of Technology
2009-01-01T23:59:59.000Z
Offshore marine risers and pipelines, exposed to ocean currents, are susceptible to Vortex-Induced Vibration (VIV). Accurate prediction of VIV is necessary for estimating the fatigue life as well as for taking corrective ...
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay
Gallay, Thierry
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay Universitâ??e de Grenoble I Institut Fourier, UMR CNRS 5582 B.P. 74 FÂ38402 SaintÂMartinÂd'Hâ??eres, France Thierry.Gallay
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay
Gallay, Thierry
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay UniversitÂ´e de Grenoble I Institut Fourier, UMR CNRS 5582 B.P. 74 F-38402 Saint-Martin-d'H`eres, France Thierry.Gallay
Mukundan, Harish
2008-01-01T23:59:59.000Z
Vortex-induced vibration (VIV) of long flexible cylindrical structures enduring ocean currents is ubiquitous in the offshore industry. Though significant effort has gone into understanding this complicated fluid-structure ...
Vortex-induced vibration of flexible cylinders in time-varying flows
Resvanis, Themistocles L
2014-01-01T23:59:59.000Z
This thesis investigates two aspects of Vortex-Induced Vibrations (VIV) on long flexible cylinders. The work is split into a minor and major part. The minor part addresses the effect of Reynolds number on flexible cylinder ...
Vortex Induced Vibrations of cylinders : experiments in reducing drag force and amplitude of motion
Farrell, David Emmanuel
2007-01-01T23:59:59.000Z
Reducing the deleterious effect of Vortex Induced Vibrations (VIV) in marine risers is an important task for ocean engineers; and many competing factors exist in the design of VIV suppression devices. This thesis explores ...
Vortex-induced vibrations of a long flexible cylinder in shear flow
Triantafyllou, Michael S.
We investigate the in-line and cross-flow vortex-induced vibrations of a long cylindrical tensioned beam, with length to diameter ratio L/D = 200, placed within a linearly sheared oncoming flow, using three-dimensional ...
Enhancement of vortex induced forces and motion through surface roughness control
Bernitsas, Michael M. (Saline, MI); Raghavan, Kamaldev (Houston, TX)
2011-11-01T23:59:59.000Z
Roughness is added to the surface of a bluff body in a relative motion with respect to a fluid. The amount, size, and distribution of roughness on the body surface is controlled passively or actively to modify the flow around the body and subsequently the Vortex Induced Forces and Motion (VIFM). The added roughness, when designed and implemented appropriately, affects in a predetermined way the boundary layer, the separation of the boundary layer, the level of turbulence, the wake, the drag and lift forces, and consequently the Vortex Induced Motion (VIM), and the fluid-structure interaction. The goal of surface roughness control is to increase Vortex Induced Forces and Motion. Enhancement is needed in such applications as harnessing of clean and renewable energy from ocean/river currents using the ocean energy converter VIVACE (Vortex Induced Vibration for Aquatic Clean Energy).
On Deformable Models for Visual Pattern Recognition
Yeung, Dit-Yan
deformable models, but some existing 2 1 2 D and 3D deformable models are also briefly reviewed. Potential has been successfully applied to recognize rigid objects, such as machinery parts and printed def (w; H j ; Â¯ w), which represents the ``energy'' of the current model with respect to the reference
Golden-Thompson's inequality for deformed exponentials
Frank Hansen
2014-10-21T23:59:59.000Z
Deformed logarithms and their inverse functions, the deformed exponentials, are important tools in the theory of non-additive entropies and non-extensive statistical mechanics. We formulate and prove counterparts of Golden-Thompson's trace inequality for q-exponentials with parameter q in the interval [1,3].
Damage and plastic deformation of reservoir rocks
Ze'ev, Reches
Damage and plastic deformation of reservoir rocks: Part 1. Damage fracturing Seth Busetti, Kyran mechanics, fluid flow in fractured reservoirs, and geomechanics in nonconventional reservoirs. Kyran Mish finite deformation of reservoir rocks. We present an at- tempt to eliminate the main limitations
Vortex in a weakly relativistic Bose gas at zero temperature and relativistic fluid approximation
B. Boisseau
2004-09-14T23:59:59.000Z
The Bogoliubov procedure in quantum field theory is used to describe a relativistic almost ideal Bose gas at zero temperature. Special attention is given to the study of a vortex. The radius of the vortex in the field description is compared to that obtained in the relativistic fluid approximation. The Kelvin waves are studied and, for long wavelengths, the dispersion relation is obtained by an asymptotic matching method and compared with the non relativistic result.
On beta-deformations and Noncommutativity
Manuela Kulaxizi
2006-10-30T23:59:59.000Z
We elucidate the connection between the N=1 beta-deformed SYM theory and noncommutativity. Our starting point is the T-duality generating transformation involved in constructing the gravity duals of both beta-deformed and noncommutative gauge theories. We show that the two methods can be identified provided that a particular submatrix of the O(3,3,R) group element employed in the former case, is interpreted as the noncommutativity parameter associated with the deformation of the transverse space. It is then explained how to construct the matrix in question, relying solely on information extracted from the gauge theory Lagrangian and basic notions of AdS/CFT. This result may provide an additional tool in exploring deformations of the N=4 SYM theory. Finally we use the uncovered relationship between beta-deformations and noncommutativity to find the gravity background dual to a noncommutative gauge theory with beta-type noncommutativity parameter.
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006Datastreamstwrcam40m DocumentationJanuary 9, 2009 [Events, FeatureListGeneralPastIce Cores Outreach Home Room
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch >InternshipDepartment of Energy with6, 2014, 6:32 p.m. (MST)BTS CORE
Liu Zhao; Guo Hongli; Fan Heng [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Vedral, Vlatko [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)
2011-01-15T23:59:59.000Z
We use entanglement to investigate the transition from vortex-liquid phase to vortex-lattice phase in a weakly interacting rotating Bose-Einstein condensate. For the torus geometry, the ground-state entanglement spectrum is analyzed to distinguish these two phases. The low-lying part of the ground-state entanglement spectrum, as well as the behavior of its lowest level, changes clearly when the transition occurs. For the sphere geometry, the entanglement gap in the conformal limit is also studied. We also show that the decrease in entanglement between particles can be regarded as a signal of the transition.
A Mechanism-based Model for Deformation Twinning in Polycrystalline...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
in Polycrystalline FCC Steel. Abstract: Deformation twinning, a common and important plastic deformation mechanism, is the key contributor to the excellent combination of...
Analysis of Crystal Lattice Deformation by Ion Channeling. |...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Crystal Lattice Deformation by Ion Channeling. Analysis of Crystal Lattice Deformation by Ion Channeling. Abstract: A model of dislocations has been developed for the use in Monte...
Steady state deformation of the Coso Range, east central California...
from satellite radar interferometry Abstract Observations of deformation from 1992 to 1997 in the southern Coso Range using satellite radar interferometry show deformation rates...
Integrable Deformations of Strings on Symmetric Spaces
Timothy J. Hollowood; J. Luis Miramontes; David M. Schmidtt
2014-07-16T23:59:59.000Z
A general class of deformations of integrable sigma-models with symmetric space F/G target-spaces are found. These deformations involve defining the non-abelian T dual of the sigma-model and then replacing the coupling of the Lagrange multiplier imposing flatness with a gauged F/F WZW model. The original sigma-model is obtained in the limit of large level. The resulting deformed theories are shown to preserve both integrability and the equations-of-motion, but involve a deformation of the symplectic structure. It is shown that this deformed symplectic structure involves a linear combination of the original Poisson bracket and a generalization of the Faddeev-Reshetikhin Poisson bracket which we show can be re-expressed as two decoupled F current algebras. It is then shown that the deformation can be incorporated into the classical model of strings on R x F/G via a generalization of the Pohlmeyer reduction. In this case, in the limit of large sigma-model coupling it is shown that the theory becomes the relativistic symmetric space sine-Gordon theory. These results point to the existence of a deformation of this kind for the full Green-Schwarz superstring on AdS5 x S5.
Deformation of Silica Aerogel During Fluid Adsorption
Tobias Herman; James Day; John Beamish
2005-06-30T23:59:59.000Z
Aerogels are very compliant materials - even small stresses can lead to large deformations. In this paper we present measurements of the linear deformation of high porosity aerogels during adsorption of low surface tension fluids, performed using a Linear Variable Differential Transformer (LVDT). We show that the degree of deformation of the aerogel during capillary condensation scales with the surface tension, and extract the bulk modulus of the gel from the data. Furthermore we suggest limits on safe temperatures for filling and emptying low density aerogels with helium.
Brian D. Hawkes; Richard Schultz
2012-07-01T23:59:59.000Z
In accordance with the need to determine whether cracking of the ceramic core disks which will be constructed and used in the High Temperature Test Facility (HTTF) for heatup and cooldown experiments, a set of calculation were performed using Abaqus to investigate the thermal stresses levels and likelihood for cracking. The calculations showed that using the material properties provided for the Greencast 94F ceramic, cracking is predicted to occur. However, this modeling does not predict the size or length of the actual cracks. It is quite likely that cracks will be narrow with rough walls which would impede the flow of coolant gases entering the cracks. Based on data recorded at Oregon State University using Greencast 94F samples that were heated and cooled at prescribed rates, it was concluded that the likelihood that the cracks would be detrimental to the experimental objectives is small.
Normal Ordering for Deformed Boson Operators and Operator-valued Deformed Stirling Numbers
Jacob Katriel; Maurice Kibler
2000-01-02T23:59:59.000Z
The normal ordering formulae for powers of the boson number operator $\\hat{n}$ are extended to deformed bosons. It is found that for the `M-type' deformed bosons, which satisfy $a a^{\\dagger} - q a^{\\dagger} a = 1$, the extension involves a set of deformed Stirling numbers which replace the Stirling numbers occurring in the conventional case. On the other hand, the deformed Stirling numbers which have to be introduced in the case of the `P-type' deformed bosons, which satisfy $a a^{\\dagger} - q a^{\\dagger} a = q^{-\\hat{n}}$, are found to depend on the operator $\\hat{n}$. This distinction between the two types of deformed bosons is in harmony with earlier observations made in the context of a study of the extended Campbell-Baker-Hausdorff formula.
Micropillar compression technique applied to micron-scale mudstone elasto-plastic deformation.
Michael, Joseph Richard; Chidsey, Thomas (Utah Geological Survey, Salt Lake City, UT); Heath, Jason E.; Dewers, Thomas A.; Boyce, Brad Lee; Buchheit, Thomas Edward
2010-12-01T23:59:59.000Z
Mudstone mechanical testing is often limited by poor core recovery and sample size, preservation and preparation issues, which can lead to sampling bias, damage, and time-dependent effects. A micropillar compression technique, originally developed by Uchic et al. 2004, here is applied to elasto-plastic deformation of small volumes of mudstone, in the range of cubic microns. This study examines behavior of the Gothic shale, the basal unit of the Ismay zone of the Pennsylvanian Paradox Formation and potential shale gas play in southeastern Utah, USA. Precision manufacture of micropillars 5 microns in diameter and 10 microns in length are prepared using an ion-milling method. Characterization of samples is carried out using: dual focused ion - scanning electron beam imaging of nano-scaled pores and distribution of matrix clay and quartz, as well as pore-filling organics; laser scanning confocal (LSCM) 3D imaging of natural fractures; and gas permeability, among other techniques. Compression testing of micropillars under load control is performed using two different nanoindenter techniques. Deformation of 0.5 cm in diameter by 1 cm in length cores is carried out and visualized by a microscope loading stage and laser scanning confocal microscopy. Axisymmetric multistage compression testing and multi-stress path testing is carried out using 2.54 cm plugs. Discussion of results addresses size of representative elementary volumes applicable to continuum-scale mudstone deformation, anisotropy, and size-scale plasticity effects. Other issues include fabrication-induced damage, alignment, and influence of substrate.
Orienting Deformable Polygonal Parts without Sensors
Kristek, Shawn
2012-02-14T23:59:59.000Z
with low-precision robot manipulators and six parts made of four types of materials. The experimental trials resulted in 154 successes, which show the feasibility of deformable parts orienting. The analysis of the failures showed that for success...
Physics-Based Deformable Tongue Visualization
Guo, Xiaohu "Tiger"
capture data gathered during speech production. Several novel deformation visualization techniques energy is utilized to provide an intuitive low dimensional visualization for the high dimensional sequential motion. Energy-interpolation-based morphing is also equipped to effectively highlight the subtle
Mechanics of deformation of carbon nanotubes
Garg, Mohit, S.M. Massachusetts Institute of Technology
2005-01-01T23:59:59.000Z
The deformation mechanics of multi-walled carbon nanotubes (MWCNT) and vertically aligned carbon nanotube (VACNT) arrays were studied using analytical and numerical methods. An equivalent orthotropic representation (EOR) ...
On q-deformed Stirling numbers
Yilmaz Simsek
2007-11-03T23:59:59.000Z
The purpose of this article is to introduce q-deformed Stirling numbers of the first and second kinds. Relations between these numbers, Riemann zeta function and q-Bernoulli numbers of higher order are given. Some relations related to the classical Stirling numbers and Bernoulli numbers of higher order are found. By using derivative operator to the generating function of the q-deformed Stirling numbers of the second kinds, a new function is defined which interpolates the q-deformed Stirling numbers of the second kinds at negative integers. The recurrence relations of the Stirling numbers of the first and second kind are given. In addition, relation between q-deformed Stirling numbers and q-Bell numbers is obtained.
Topological superconductivity, topological confinement, and the vortex quantum Hall effect
Diamantini, M. Cristina; Trugenberger, Carlo A. [INFN and Dipartimento di Fisica, University of Perugia, via A. Pascoli, I-06100 Perugia (Italy); SwissScientific, chemin Diodati 10, CH-1223 Cologny (Switzerland)
2011-09-01T23:59:59.000Z
Topological matter is characterized by the presence of a topological BF term in its long-distance effective action. Topological defects due to the compactness of the U(1) gauge fields induce quantum phase transitions between topological insulators, topological superconductors, and topological confinement. In conventional superconductivity, because of spontaneous symmetry breaking, the photon acquires a mass due to the Anderson-Higgs mechanism. In this paper we derive the corresponding effective actions for the electromagnetic field in topological superconductors and topological confinement phases. In topological superconductors magnetic flux is confined and the photon acquires a topological mass through the BF mechanism: no symmetry breaking is involved, the ground state has topological order, and the transition is induced by quantum fluctuations. In topological confinement, instead, electric charge is linearly confined and the photon becomes a massive antisymmetric tensor via the Stueckelberg mechanism. Oblique confinement phases arise when the string condensate carries both magnetic and electric flux (dyonic strings). Such phases are characterized by a vortex quantum Hall effect potentially relevant for the dissipationless transport of information stored on vortices.
Noncommutative scalar fields from symplectic deformation
Daoud, M. [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34014 Trieste (Italy); Hamama, A. [High Energy Laboratory, Faculty of Sciences, University Mohamed V, P.O. Box 1014, Rabat (Morocco)
2008-02-15T23:59:59.000Z
This paper is concerned with the quantum theory of noncommutative scalar fields in two dimensional space-time. It is shown that the noncommutativity originates from the the deformation of symplectic structures. The quantization is performed and the modes expansions of the fields, in the presence of an electromagnetic background, are derived. The Hamiltonian of the theory is given and the degeneracies lifting, induced by the deformation, is also discussed.
Direct Rendering of Deformable Volume Data Shiaofen Fang
Fang, Shiaofen
Direct Rendering of Deformable Volume Data Shiaofen Fang Department of Computer and Information In this paper, we present a new deformable volume rendering algorithm. The volume deformation is modeled to directly render the deformed volume without going through the expensive volume construction process
Influence of plastic deformation on bimaterial fault rupture directivity
Dmowska, Renata
Influence of plastic deformation on bimaterial fault rupture directivity Nora DeDontney,1 Elizabeth of the role of the stress state on the distribution of plastic deformation and the direction of preferred in determining the location of plastic deformation. For different orientations, plastic deformation can
Deformation Behavior of Nanoporous Metals
Biener, J; Hodge, A M; Hamza, A V
2007-11-28T23:59:59.000Z
Nanoporous open-cell foams are a rapidly growing class of high-porosity materials (porosity {ge} 70%). The research in this field is driven by the desire to create functional materials with unique physical, chemical and mechanical properties where the material properties emerge from both morphology and the material itself. An example is the development of nanoporous metallic materials for photonic and plasmonic applications which has recently attracted much interest. The general strategy is to take advantage of various size effects to introduce novel properties. These size effects arise from confinement of the material by pores and ligaments, and can range from electromagnetic resonances to length scale effects in plasticity. In this chapter we will focus on the mechanical properties of low density nanoporous metals and how these properties are affected by length scale effects and bonding characteristics. A thorough understanding of the mechanical behavior will open the door to further improve and fine-tune the mechanical properties of these sometimes very delicate materials, and thus will be crucial for integrating nanoporous metals into products. Cellular solids with pore sizes above 1 micron have been the subject of intense research for many years, and various scaling relations describing the mechanical properties have been developed.[4] In general, it has been found that the most important parameter in controlling their mechanical properties is the relative density, that is, the density of the foam divided by that of solid from which the foam is made. Other factors include the mechanical properties of the solid material and the foam morphology such as ligament shape and connectivity. The characteristic internal length scale of the structure as determined by pores and ligaments, on the other hand, usually has only little effect on the mechanical properties. This changes at the submicron length scale where the surface-to-volume ratio becomes large and the effect of free surfaces can no longer be neglected. As the material becomes more and more constraint by the presence of free surfaces, length scale effects on plasticity become more and more important and bulk properties can no longer be used to describe the material properties. Even the elastic properties may be affected as the reduced coordination of surface atoms and the concomitant redistribution of electrons may soften or stiffen the material. If, and to what extend, such length scale effects control the mechanical behavior of nanoporous materials depends strongly on the material and the characteristic length scale associated with its plastic deformation. For example, ductile materials such as metals which deform via dislocation-mediated processes can be expected to exhibit pronounced length scale effects in the sub-micron regime where free surfaces start to constrain efficient dislocation multiplication. In this chapter we will limit our discussion to our own area of expertise which is the mechanical behavior of nanoporous open-cell gold foams as a typical example of nanoporous metal foams. Throughout this chapter we will review our current understanding of the mechanical properties of nanoporous open-cell foams including both experimental and theoretical studies.
OTEC cold water pipe design for problems caused by vortex-excited oscillations
Griffin, O. M.
1980-03-14T23:59:59.000Z
Vortex-excited oscillations of marine structures result in reduced fatigue life, large hydrodynamic forces and induced stresses, and sometimes lead to structural damage and to diestructive failures. The cold water pipe of an OTEC plant is nominally a bluff, flexible cylinder with a large aspect ratio (L/D = length/diameter), and is likely to be susceptible to resonant vortex-excited oscillations. The objective of this report is to survey recent results pertaining to the vortex-excited oscillations of structures in general and to consider the application of these findings to the design of the OTEC cold water pipe. Practical design calculations are given as examples throughout the various sections of the report. This report is limited in scope to the problems of vortex shedding from bluff, flexible structures in steady currents and the resulting vortex-excited oscillations. The effects of flow non-uniformities, surface roughness of the cylinder, and inclination to the incident flow are considered in addition to the case of a smooth cyliner in a uniform stream. Emphasis is placed upon design procedures, hydrodynamic coefficients applicable in practice, and the specification of structural response parameters relevant to the OTEC cold water pipe. There are important problems associated with in shedding of vortices from cylinders in waves and from the combined action of waves and currents, but these complex fluid/structure interactions are not considered in this report.
A Robust Numerical Method for Integration of Point-Vortex Trajectories in Two Dimensions
Spencer A. Smith; Bruce M. Boghosian
2010-11-19T23:59:59.000Z
The venerable 2D point-vortex model plays an important role as a simplified version of many disparate physical systems, including superfluids, Bose-Einstein condensates, certain plasma configurations, and inviscid turbulence. This system is also a veritable mathematical playground, touching upon many different disciplines from topology to dynamic systems theory. Point-vortex dynamics are described by a relatively simple system of nonlinear ODEs which can easily be integrated numerically using an appropriate adaptive time stepping method. As the separation between a pair of vortices relative to all other inter-vortex length scales decreases, however, the computational time required diverges. Accuracy is usually the most discouraging casualty when trying to account for such vortex motion, though the varying energy of this ostensibly Hamiltonian system is a potentially more serious problem. We solve these problems by a series of coordinate transformations: We first transform to action-angle coordinates, which, to lowest order, treat the close pair as a single vortex amongst all others with an internal degree of freedom. We next, and most importantly, apply Lie transform perturbation theory to remove the higher-order correction terms in succession. The overall transformation drastically increases the numerical efficiency and ensures that the total energy remains constant to high accuracy.
Numerical study of Kelvin-Helmholtz instability by the point vortex method
Krasny, R.
1983-01-01T23:59:59.000Z
Rosenhead's classical point vortex numerical method for studying the evolution of a vortex sheet from analytic initial data (Kelvin-Helmholtz instability) is examined using the discrete Fourier analysis techniques of Sulem, Sulem and Frisch. One cause for the chaotic motion previously observed in computations using a large number of vortices is that short wavelength perturbations are introduced spuriously by finite precision arithmetic and become amplified by the model's dynamics. Methods for controlling this source of error are given, and the results confirm the formation of a singularity in a finite time which was previously found by Moore and Meiron, Baker and Orszag using different techniques of analysis. A cusp forms in the vortex sheet strength at the critical time, explaining the onset of erratic particle motion in applications of the numerical methods of Van de Vooren and Fink and Soh to this problem. Unlike those methods, the point vortex approximation remains consistent at the critical time and results of a long time calculation are presented. The singularity is interpreted physically as a discontinuity in the strain rate along the vortex sheet and also as the start of roll up on a small scale. The author numerically studies some aspects of the dependence of the solution on the initial condition and finds agreement with Moore's asymptotic relation between the initial amplitude and the critial time.
van Hemmen, J. Leo
that pass a fish later- ally [19] as well as vortex rings that are part of a von Ka´rma´n vortex street [20 by the lateral-line sensors so as to enable fish to follow a vortex street. DOI: 10.1103/PhysRevLett.103Wake Tracking and the Detection of Vortex Rings by the Canal Lateral Line of Fish Jan-Moritz P
Electron Abundance in Protostellar Cores
Paolo Padoan; Karen Willacy; William Langer; Mika Juvela
2004-06-23T23:59:59.000Z
The determination of the fractional electron abundance, Xe, in protostellar cores relies on observations of molecules, such as DCO+, H13CO+ and CO, and on chemical models to interpret their abundance. Studies of protostellar cores have revealed significant variations of Xe from core to core within a range 10^-8
Lindsay, Ron
of the Arctic geophysical environment. The deformation rate of pack ice, determined from the spatial gradientsRGPS/Model Ice Deformation July 3, 2003 1 Sea Ice Deformation Rates From Satellite Measurements The deformation of sea ice is an important element of the Arctic climate system because of its influence
Ahsan Choudhuri
2011-03-31T23:59:59.000Z
Turbine combustors of advanced power systems have goals to achieve very low pollutants emissions, fuel variability, and fuel flexibility. Future generation gas turbine combustors should tolerate fuel compositions ranging from natural gas to a broad range of syngas without sacrificing operational advantages and low emission characteristics. Additionally, current designs of advanced turbine combustors use various degrees of swirl and lean premixing for stabilizing flames and controlling high temperature NOx formation zones. However, issues of fuel variability and NOx control through premixing also bring a number of concerns, especially combustor flashback and flame blowout. Flashback is a combustion condition at which the flame propagates upstream against the gas stream into the burner tube. Flashback is a critical issue for premixed combustor designs, because it not only causes serious hardware damages but also increases pollutant emissions. In swirl stabilized lean premixed turbine combustors onset of flashback may occur due to (i) boundary layer flame propagation (critical velocity gradient), (ii) turbulent flame propagation in core flow, (iii) combustion instabilities, and (iv) upstream flame propagation induced by combustion induced vortex breakdown (CIVB). Flashback due to first two foregoing mechanisms is a topic of classical interest and has been studied extensively. Generally, analytical theories and experimental determinations of laminar and turbulent burning velocities model these mechanisms with sufficient precision for design usages. However, the swirling flow complicates the flashback processes in premixed combustions and the first two mechanisms inadequately describe the flashback propensity of most practical combustor designs. The presence of hydrogen in syngas significantly increases the potential for flashback. Due to high laminar burning velocity and low lean flammability limit, hydrogen tends to shift the combustor operating conditions towards flashback regime. Even a small amount of hydrogen in a fuel blend triggers the onset of flashback by altering the kinetics and thermophysical characteristics of the mixture. Additionally, the presence of hydrogen in the fuel mixture modifies the response of the flame to the global effects of stretch and preferential diffusion. Despite its immense importance in fuel flexible combustor design, little is known about the magnitude of fuel effects on CIVB induced flashback mechanism. Hence, this project investigates the effects of syngas compositions on flashback resulting from combustion induced vortex breakdown. The project uses controlled experiments and parametric modeling to understand the velocity field and flame interaction leading to CIVB driven flashback.
Paris-Sud XI, Université de
Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel deposition graphene on glass substrate using femtosecond laser ablation with vortex Bessel beams. The fabricated graphene disks with diameters ranging from 650 nm to 4 µm were characterized by spatially resolved
Joule heating induced by vortex motion in a type-II superconductor Z. L. Xiao and E. Y. Andrei
Andrei, Eva Y.
Joule heating induced by vortex motion in a type-II superconductor Z. L. Xiao and E. Y. Andrei-II superconductor due to Joule heating induced by vortex motion. The effect of Joule heating is detected s duration, where the Joule heating is negligible and saturates, respectively. The thermometry is based
Boyer, Edmond
Bow-wave-like hydraulic jump and horseshoe vortex around an obstacle in a supercritical open the obstacle, two main flow structures are observed: i a hydraulic jump in the near-surface region and ii turbulent regime , the detachment length of the hydraulic jump exceeds the one of the horseshoe vortex
Vortex dipoles by PIV method Click here to see the images and the short movies from this lab
deYoung, Brad
Introduction A vortex dipole is a jet flow with a system of two vortices of opposite sign at its front. Vortex of density stratification. The simplest case of stratification is a two-layer system. A Plexiglas tank a two-layer system without mixing the fluids, one can float a sheet of paper on top of the salt water
Mohseni, Kamran
field around a fish's body in the presence of a Karman vortex street. Karman and reverse Karman streets LLTC model could explain how a fish identifies the characteristics of a Karman vortex street shed that the main characteristics of a vortex street including the magnitude of vortices, their translational speed
Reduction of vortex induced forces and motion through surface roughness control
Bernitsas, Michael M; Raghavan, Kamaldev
2014-04-01T23:59:59.000Z
Roughness is added to the surface of a bluff body in a relative motion with respect to a fluid. The amount, size, and distribution of roughness on the body surface is controlled passively or actively to modify the flow around the body and subsequently the Vortex Induced Forces and Motion (VIFM). The added roughness, when designed and implemented appropriately, affects in a predetermined way the boundary layer, the separation of the boundary layer, the level of turbulence, the wake, the drag and lift forces, and consequently the Vortex Induced Motion (VIM), and the fluid-structure interaction. The goal of surface roughness control is to decrease/suppress Vortex Induced Forces and Motion. Suppression is required when fluid-structure interaction becomes destructive as in VIM of flexible cylinders or rigid cylinders on elastic support, such as underwater pipelines, marine risers, tubes in heat exchangers, nuclear fuel rods, cooling towers, SPAR offshore platforms.
Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel
Steele, Robert C; Edmonds, Ryan G; Williams, Joseph T; Baldwin, Stephen P
2012-11-20T23:59:59.000Z
A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.
Random Vortex-Street Model for a Self-Similar Plane Turbulent Jet
Victor L'vov; Anna Pomyalov; Itamar Procaccia; Rama Govindarajan
2008-03-18T23:59:59.000Z
We ask what determines the (small) angle of turbulent jets. To answer this question we first construct a deterministic vortex-street model representing the large scale structure in a self-similar plane turbulent jet. Without adjustable parameters the model reproduces the mean velocity profiles and the transverse positions of the large scale structures, including their mean sweeping velocities, in a quantitative agreement with experiments. Nevertheless the exact self similar arrangement of the vortices (or any other deterministic model) necessarily leads to a collapse of the jet angle. The observed (small) angle results from a competition between vortex sweeping tending to strongly collapse the jet and randomness in the vortex structure, with the latter resulting in a weak spreading of the jet.
Shear Banding and Spatiotemporal Oscillations in Vortex Matter in Nanostructured Superconductors
C. Reichhardt; C. J. Olson Reichhardt
2009-12-16T23:59:59.000Z
We propose a simple nanostructured pinning array geometry where a rich variety of complex vortex shear banding phenomena can be realized. A single row of pinning sites is removed from a square pinning array. Shear banding effects arise when vortex motion in the pin-free channel nucleates motion of vortices in the surrounding pinned regions, creating discrete steps in the vortex velocity profile away from the channel. Near the global depinning transition, the width of the band of moving vortices undergoes oscillations or fluctuations that can span the entire system. We use simulations to show that these effects should be observable in the transport properties of the system. Similar large oscillations and shear banding effects are known to occur for sheared complex fluids in which different dynamical phases coexist.
Vortex combustor for low NOx emissions when burning lean premixed high hydrogen content fuel
Steele, Robert C. (Woodinville, WA); Edmonds, Ryan G. (Renton, WA); Williams, Joseph T. (Kirkland, WA); Baldwin, Stephen P. (Winchester, MA)
2009-10-20T23:59:59.000Z
A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.
Estimating dispersion from a tornado vortex and mesocyclone
Weber, A.H.; Hunter, C.H.
1996-06-01T23:59:59.000Z
Atmospheric dispersion modeling is required to ensure that a postulated breach in radionuclide storage containers at the Savannah River Site (SRS) from a tornado strike of Fujita-scale intensity F2 or higher will not result in an unacceptable dose to individuals. Fujita-scale tornado descriptions are included in Appendix A of this report. Dispersion models previously used at SRS for estimating dispersion following a tornado strike were developed by D.W. Pepper in 1975 (DP-1387, Dispersion of Small Particles) and H.R. Haynes and D.W. Taylor in 1983 (DPST-82-982, Estimating Doses from Tornado Winds). Research conducted in 1983 on the formation and evolution of tornadic thunderstorms has lead to a more complete understanding of the tornado vortex and associated persistent updraft and downdraft regions within the parent thunderstorm. To ensure that appropriate, contemporary methods are used for safety analysis, the Pepper model and the Haynes and Taylor model were evaluated with respect to current knowledge of circulations within tornadic thunderstorms. Pepper`s model is complex numerically but contains most of the desired physical parameterizations. Haynes and Taylor`s model is used with the Puff-Plume model (an emergency response model on the Weather INformation and Display System at SRS) and has provisions for radionuclide deposition and rainout. Haynes and Taylor assumed heavy rain following the tornado for a period of ten minutes, followed by a lighter rain for another ten minutes, then no rain for the period when the material is transported to 100 km downwind. However, neither model incorporates the effects of a nearby thunderstorm downdraft.
Formation of multi-solitons and vortex bright solitons in Bose-condensed alkali-metal atoms
Luca Salasnich
2003-09-02T23:59:59.000Z
Formation of multi-solitons and vortex bright solitons in Bose-condensed alkali-metal atoms is analyzed by using the nonpolynomial Schordinger equation. A train of bright solitons is obtained from an axially homogeneous Bose-Einstein condensate by a sudden change of the scattering length from repulsive to attractive. We derive an analytical expression for the number of bright solitons generated by using this mechanism. The formula generalizes a previous formula obtained with the 1D Gross-Pitaevskii equation. In the second part we consider vortex bright solitons, namely cigar-shaped bright solitons with a nonzero angular quantum number $k$ along the axial direction. By using a variational approach we determine the shape of vortex bright solitons, showing that the critical number of atoms for the collapse of the vortex soliton increases with a larger $k$. Finally we calculate monopole and quadrupole collective oscillations of these vortex bright solitons.
Bent core liquid crystal elastomers
Verduzco, R.; DiMasi, E.; Luchette, P.; Ho Hong, S.; Harden, J.; Palffy-Muhoray, P.; Kilbey II, S.M.; Sprunt, S.; Gleeson, G.T. Jakli, A.
2010-07-28T23:59:59.000Z
Liquid crystal (LC) elastomers with bent-core side-groups incorporate the properties of bent-core liquid crystals in a flexible and self-supporting polymer network. Bent-core liquid crystal elastomers (BCEs) with uniform alignment were prepared by attaching a reactive bent-core LC to poly(hydrogenmethylsiloxane) and crosslinking with a divinyl crosslinker. Phase behavior studies indicate a nematic phase over a wide temperature range that approaches room temperature, and thermoelastic measurements show that these BCEs can reversibly change their length by more than a factor of two upon heating and cooling. Small-angle X-ray scattering studies reveal multiple, broad low-angle peaks consistent with short-range smectic C order of the bent-core side groups. A comparison of these patterns with predictions of a Landau model for short-range smectic C order shows that the length scale for smectic ordering in BCEs is similar to that seen in pure bent-core LCs. The combination of rubber elasticity and smectic ordering of the bent-core side groups suggests that BCEs may be promising materials for sensing, actuating, and other advanced applications.
Numerical study of Kelvin-Helmholtz instability by the point vortex method
Krasny, R.
1983-12-01T23:59:59.000Z
Rosenhead's classical point vortex numerical method for studying the evolution of a vortex sheet from analytic initial data (Kelvin-Helmholtz instability) is examined using the discrete Fourier analysis techniques of Sulem, Sulem and Frisch. One cause for the chaotic motion previously observed in computations using a large number of vortices is that short wavelength perturbations are introduced spuriously by finite precision arithmetic and become amplified by the model's dynamics. Methods for controlling this source of error are given and the results confirm the formation of a singularity in a finite time which was previously found by Moore and Meiron, Baker and Orszag using different techniques of analysis. A cusp forms in the vortex sheet strength at the critical time, explaining the onset of erratic particle motion in applications of the numerical methods of Van de Vooren and Fink and Soh to this problem. Unlike those methods, the point vortex approximation remains consistent at the critical time and we present the results of a long time calculation. The singularity is interpreted physically as a discontinuity in the strain rate along the vortex sheet and also as the start of roll up on a small scale. We numerically study some aspects of the dependence of the solution on the initial condition and find agreement with Moore's asymptotic relation between the initial amplitude and the critical time. For large initial amplitudes, two cusps form in the sheet strength, corresponding to double roll up. We explain why the Poincare recurrenc theorem does not imply that the sheet will eventually unroll. Our results suggest that beyond the critical time, the vortex sheet becomes a spiral with infinite arclength although we have doubts about the approximation's accuracy in that regime. 36 references, 30 figures, 3 tables.
The effects of a jet on vortex breakdown over a sharp leading-edge delta wing
Maynard, Ian Kenneth
1985-01-01T23:59:59.000Z
THE EFFECTS OF A JET ON VORTEX BREAKDOWN OVER A SHARP LEADING-EDGE DELTA WING A Thesis Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1985... Major Subject: Aerospace Engineering THE EFFECTS OF A JET ON VORTEX BREAKDOWN OVER A SHARP LEADING-EDGE DELTA WING A Thesis by IAN KENNETH MAYNARD Approved as to style and content by: Cyrus Ostowar (Chairman of Committee) Stan J Miley (M er...
Streamline topology and dilute particle dynamics in a Karman vortex street flow
Wu, Z B
2003-01-01T23:59:59.000Z
Three types of streamline topology in a Karman vortex street flow are shown under the variation of spatial parameters. For the motion of dilute particles in the K\\'arm\\'an vortex street flow, there exist a route of bifurcation to a chaotic orbit and more attractors in a bifurcation diagram for the proportion of particle density to fluid density. Along with the increase of spatial parameters in the flow filed, the bifurcation process is suspended, as well as more and more attractors emerge. In the motion of dilute particles, a drag term and gravity term dominate and result in the bifurcation phenomenon.
Density fluctuations in $?$-deformed inflationary universe
Hyeong-Chan Kim; Jae Hyung Yee; Chaiho Rim
2005-10-27T23:59:59.000Z
We study the spectrum of metric fluctuation in $\\kappa$-deformed inflationary universe. We write the theory of scalar metric fluctuations in the $\\kappa-$deformed Robertson-Walker space, which is represented as a non-local theory in the conventional Robertson-Walker space. One important consequence of the deformation is that the mode generation time is naturally determined by the structure of the $\\kappa-$deformation. We expand the non-local action in $H^2/\\kappa^2$, with $H$ being the Hubble parameter and $\\kappa$ the deformation parameter, and then compute the power spectra of scalar metric fluctuations both for the cases of exponential and power law inflations up to the first order in $H^2/\\kappa^2$. We show that the power spectra of the metric fluctuation have non-trivial corrections on the time dependence and on the momentum dependence compared to the commutative space results. Especially for the power law inflation case, the power spectrum for UV modes is weakly blue shifted early in the inflation and its strength decreases in time. The power spectrum of far-IR modes has cutoff proportional to $k^3$ which may explain the low CMB quadrupole moment.
Noncommutative Deformations of Wightman Quantum Field Theories
Harald Grosse; Gandalf Lechner
2008-08-26T23:59:59.000Z
Quantum field theories on noncommutative Minkowski space are studied in a model-independent setting by treating the noncommutativity as a deformation of quantum field theories on commutative space. Starting from an arbitrary Wightman theory, we consider special vacuum representations of its Weyl-Wigner deformed counterpart. In such representations, the effect of the noncommutativity on the basic structures of Wightman theory, in particular the covariance, locality and regularity properties of the fields, the structure of the Wightman functions, and the commutative limit, is analyzed. Despite the nonlocal structure introduced by the noncommutativity, the deformed quantum fields can still be localized in certain wedge-shaped regions, and may therefore be used to compute noncommutative corrections to two-particle S-matrix elements.
Plastic Deformation of 2D Crumpled Wires
M A F Gomes; V P Brito; A S O Coelho; C C Donato
2008-11-17T23:59:59.000Z
When a single long piece of elastic wire is injected trough channels into a confining two-dimensional cavity, a complex structure of hierarchical loops is formed. In the limit of maximum packing density, these structures are described by several scaling laws. In this paper it is investigated this packing process but using plastic wires which give origin to completely irreversible structures of different morphology. In particular, it is studied experimentally the plastic deformation from circular to oblate configurations of crumpled wires, obtained by the application of an axial strain. Among other things, it is shown that in spite of plasticity, irreversibility, and very large deformations, scaling is still observed.
Deformation of contour and Hawking temperature
Chikun Ding; Jiliang Jing
2010-01-19T23:59:59.000Z
It was found that, in an isotropic coordinate system, the tunneling approach brings a factor of 1/2 for the Hawking temperature of a Schwarzschild black hole. In this paper, we address this kind of problem by studying the relation between the Hawking temperature and the deformation of integral contour for the scalar and Dirac particles tunneling. We find that correct Hawking temperature can be obtained exactly as long as the integral contour deformed corresponding to the radial coordinate transform if the transformation is a non-regular or zero function at the event horizon.
A Noncommutative Deformation of Topological Field Theory
Hugo Garcia-Compean; Pablo Paniagua
2004-02-21T23:59:59.000Z
Cohomological Yang-Mills theory is formulated on a noncommutative differentiable four manifold through the $\\theta$-deformation of its corresponding BRST algebra. The resulting noncommutative field theory is a natural setting to define the $\\theta$-deformation of Donaldson invariants and they are interpreted as a mapping between the Chevalley-Eilenberg homology of noncommutative spacetime and the Chevalley-Eilenberg cohomology of noncommutative moduli of instantons. In the process we find that in the weak coupling limit the quantum theory is localized at the moduli space of noncommutative instantons.
PLASTIC DEFORMATION OF CRYSTALS: ANALYTICAL AND COMPUTER SIMULATION STUDIES OF DISLOCATION GLIDE
Altintas, Sabri
2011-01-01T23:59:59.000Z
in Rate Processes in Plastic Deformation of Materials, J. C.PLASTIC DEFORMATION OF CRYSTALS: ANALYTICAL AND COMPUTERCAPTIONS FIGURES - iii - PLASTIC DEFORMATION OF CRYSTALS:
Effect of Field Dependent Core Size on Reversible Magnetization of High-? Superconductors
Kogan, V. G. [Ames Laboratory and Iowa State University; Prozorov, R. [Ames Laboratory and Iowa State University; Bud'ko, S. L. [Ames Laboratory; Canfield, P. C. [Ames Laboratory; Thompson, James R [ORNL; Karpinski, J. [Swiss Federal Institute of Technology; Zhigadlo, N. D. [Swiss Federal Institute of Technology; Miranovic, P. [University of Montenegro, Serbia and Montenegro
2006-01-01T23:59:59.000Z
The field dependence of the vortex core size {zeta}(B) is incorporated in the London model, in order to describe reversible magnetization M(B,T) for a number of materials with large Ginzburg-Landau parameter {kappa}. The dependence {zeta}(B) is directly related to deviations in M(ln B) from linear behavior prescribed by the standard London model. A simple method to extract {zeta}(B) from the magnetization data is proposed. For most materials examined, {zeta}(B) so obtained decreases with increasing field and is in qualitative agreement both with behavior extracted from {micro}SR and small-angle neutron-scattering data and with that predicted theoretically.
Effect of asymmetric axial strain on the behavior of the juncture vortex system
Trosper, Jeffrey Randall
1994-01-01T23:59:59.000Z
The objective of this research was to investigate the behavior of the vortex formed in a wing-body juncture in a water tunnel flow. The wing-body juncture was created by mounting a symmetrical airfoil with an elliptical leading edge normal to a flat...
A Lagrangian approach to identifying vortex pinch-off Clara O'Farrell1
Dabiri, John O.
A Lagrangian approach to identifying vortex pinch-off Clara O'Farrell1 and John O. Dabiri2 1 Control and Dynamical Systems, California Institute of Technology, Pasadena, California 91125, USA 2 Graduate Aeronautical Laboratories and Bioengineering, California Institute of Technology, Pasadena
Crown copyright Met Office Hurricane dynamics: on the role of Vortex Rossby Waves (VRWs).
© Crown copyright Met Office Hurricane dynamics: on the role of Vortex Rossby Waves (VRWs). Gilbert of numerical weather prediction: hurricanes, typhoons and tropical cyclones · Hurricane intensity · Conclusion #12;© Crown copyright Met Office Hurricane Juan, 28 September 2003, Halifax 75°N 110°W 10°E5°N
Indirect Combustion Noise: Experimental Investigation of the Vortex Sound Generation in a Choked
Paris-Sud XI, Université de
Indirect Combustion Noise: Experimental Investigation of the Vortex Sound Generation in a Choked-27 April 2012, Nantes, France 2315 #12;Combustion noise in gas turbines consists of direct noise related to the unsteady combustion process itself and indirect noise. As known, indirect noise is produced when entropy
Observations of wave-generated vortex ripples on the North Carolina continental shelf
Kirby, James T.
October 2002. [1] Sand ripples with wavelengths between 0.5 and 3 m were observed on the bottom across, 1882; Forel, 1883; Dingler, 1974; Vincent and Osborne, 1993; Gallagher et al., 1998; Traykovski et al ripples'' by Bagnold [1946], exert a much larger drag on the flow than friction on sand grains. Vortex
Simulation of vortex sheet roll-up: chaos, azimuthal waves, ring merger
Krasny, Robert
Simulation of vortex sheet roll-up: chaos, azimuthal waves, ring merger Robert KRASNY1 , Keith-1109 USA krasny@umich.edu National Center for Atmospheric Research, Climate andGlobal Dynamics Boulder, axisymmetric, and three- dimensional flow Krasny &Nitsche 2001; Lindsay & Krasny 2001. Vor- tex sheet
On the bifurcation structure of axisyrnmetric vortex breakdown in a constricted pipe
Lopez, John M.
On the bifurcation structure of axisyrnmetric vortex breakdown in a constricted pipe J. M. Lopez Department of Mathematics and Earth SystemScienceCenter;The PennsylvaniaState University, Universiv Park, Pennsylvania 16802 (Received 5 April 1994; accepted 20 July 1994) The bifurcation structure is presented
Complex Langevin simulation of quantum vortex nucleation in the Bose-Einstein condensate
Tomoya Hayata; Arata Yamamoto
2014-11-19T23:59:59.000Z
The ab-initio simulation of quantum vortex nucleation in the Bose-Einstein condensate is performed by adopting the complex Langevin techniques. We simulate the two-component boson field theory at a finite chemical potential under rotation. In the superfluid phase, vortices are generated above a critical angular velocity and the circulation is clearly quantized even in the presence of quantum fluctuations.
Rakowski, Cynthia L.; Richmond, Marshall C.; Serkowski, John A.
2006-12-01T23:59:59.000Z
A computational fluid dynamics (CFD) model was used in an investigation into the suppression of a surface vortex that forms and the south-most spilling bay at The Dalles Project. The CFD work complemented work at the prototype and the reduced-scale physical models. The CFD model was based on a model developed for other work in the forebay but had additional resolution added near the spillway. Vortex suppression devices (VSDs) were to placed between pier noses and/or in the bulkhead slot of the spillway bays. The simulations in this study showed that placing VSD structures or a combination of structures to suppress the vortex would still result in near-surface flows to be entrained in a vortex near the downstream spillwall. These results were supported by physical model and prototype studies. However, there was a consensus of the fish biologists at the physical model that the fish would most likely move north and if the fish went under the VSD it would immediately exit the forebay through the tainter gate and not get trapped between VSDs or the VSDs and the tainter gate if the VSDs were deep enough.
Wavelet analysis of vortex breakdown Jori E. Ruppert-Felsot1
École Normale Supérieure
Wavelet analysis of vortex breakdown Jori E. Ruppert-Felsot1 , Marie Farge1 , and Philippe the experimentally mea- sured flow field using orthogonal wavelets to observe the time evolution of the bursting. The discrete wavelet transform is used to separate the flow field into a coherent component, capturing
2094 OPTICS LETTERS / Vol. 28, No. 21 / November 1, 2003 Fundamental and vortex solitons in a
Yang, Jianke
2094 OPTICS LETTERS / Vol. 28, No. 21 / November 1, 2003 Fundamental and vortex solitons in a two-dimensional optical lattice Jianke Yang Department of Mathematics and Statistics, University of Vermont, Burlington-dimensional optically induced waveguide array are reported. In the strong localization regime the fundamental soliton
Reduced gravity rankine cycle design and optimization with passive vortex phase separation
Supak, Kevin Robert
2009-05-15T23:59:59.000Z
Interphase Transport Phenomena kW(e) Kilowatts-Electric MVS Microgravity Vortex Separator ORNL Oak Ridge National Laboratory SNAP Systems For Nuclear Auxiliary Power MPRE Medium Power Reactor Experiment RFMD Rotary Fluid Management Device RPM...............................................................................................3 History of Space Rankine Cycle Development .....................................6 ORNL Rankine Cycle Design..............................................................10 Space Rankine Cycle Components...
Supak, Kevin Robert
2008-10-10T23:59:59.000Z
Interphase Transport Phenomena kW(e) Kilowatts-Electric MVS Microgravity Vortex Separator ORNL Oak Ridge National Laboratory SNAP Systems For Nuclear Auxiliary Power MPRE Medium Power Reactor Experiment RFMD Rotary Fluid Management Device RPM...............................................................................................3 History of Space Rankine Cycle Development .....................................6 ORNL Rankine Cycle Design..............................................................10 Space Rankine Cycle Components...
Vortex Liquid Crystals in Anisotropic Type II Superconductors E.W. Carlson,1,2
Carlson, Erica
Vortex Liquid Crystals in Anisotropic Type II Superconductors E.W. Carlson,1,2 A. H. Castro Neto,1 September 2002; published 25 February 2003) In an isotropic type II superconductor in a moderate magnetic been much interest in high tem- perature superconductors in a magnetic field. Various ex- periments
Two regimes of vortex penetration into platelet-shaped type-II superconductors
Brandt, E. H. [Max-Planck-Institut fuer Metallforschung (Germany)] [Max-Planck-Institut fuer Metallforschung (Germany); Mikitik, G. P., E-mail: mikitik@ilt.kharkov.ua [Ukrainian Academy of Sciences, Verkin Institute for Low Temperature Physics and Engineering (Ukraine); Zeldov, E. [Weizmann Institute of Science, Department of Condensed Matter Physics (Israel)] [Weizmann Institute of Science, Department of Condensed Matter Physics (Israel)
2013-09-15T23:59:59.000Z
Vortex penetration into a thin superconducting strip of a rectangular cross section is considered at an increasing applied magnetic field H{sub a}, taking an interplay between the Bean-Livingston and the geometric barriers in the sample into account. We calculate the magnetic field H{sub p} at which the penetration begins and show that two regimes of vortex penetration are possible. In the first regime, vortices appearing at the corners of the strip at H{sub a} = H{sub p} immediately move to its center, where a vortex dome starts to develop. In the second regime, the penetration occurs in two stages. In the first stage, at H{sub a} < H{sub p}, tilted vortices penetrate into the edge regions of the strip, where novel domes are shown to be formed at the top, bottom, and lateral surfaces. In the second stage, at H{sub a} = H{sub p}, the vortex propagation to the center becomes possible. The difference between the regimes manifests itself in slightly different dependences of the magnetic moment of the strip on H{sub a}.
Origin of Reversed Vortex Ratchet Motion W. Gillijns, A. V. Silhanek, and V. V. Moshchalkov
Moshchalkov, Victor V.
Origin of Reversed Vortex Ratchet Motion W. Gillijns, A. V. Silhanek, and V. V. Moshchalkov INPAC. This rectified motion of particles, known as a rocked ratchet, is basically the result of the broken spatial that the particles (flux lines) cannot be regarded as independent entities leads to a far richer ratchet motion
BAROCLINIC VORTICITY PRODUCTION IN PROTOPLANETARY DISKS. II. VORTEX GROWTH AND LONGEVITY
Julien, Keith
BAROCLINIC VORTICITY PRODUCTION IN PROTOPLANETARY DISKS. II. VORTEX GROWTH AND LONGEVITY Mark R -- instabilities -- methods: numerical -- solar system: formation -- turbulence Online material: color figures 1 the surface. Thus, the potential energy of the tilted isopycnals is converted into the kinetic energy
Vortex avalanches with robust statistics observed in superconducting niobium E. Altshuler,1,2
Zeldov, Eli
Vortex avalanches with robust statistics observed in superconducting niobium E. Altshuler,1,2 T. H topography of superconducting niobium samples as the external field is slowly increased. The avalanche size in Ref. 11, was quite limited, being based on only a few hundred events. Nowak et al.12 studied niobium
Vortex-Pair Dynamics in Anisotropic Bistable Media: A Kinematic Approach Aric Hagberg1
Hagberg, Aric
Vortex-Pair Dynamics in Anisotropic Bistable Media: A Kinematic Approach Aric Hagberg1 and Ehud typically evolves into rotating spiral waves. In an anisotropic system, instead of spiral waves, the vortices can form wave fragments that propagate with a constant speed in a given direction determined
Particle resuspension by an impacting vortex ring RICK J. MUNRO & STUART B. DALZIEL
Dalziel, Stuart
Particle resuspension by an impacting vortex ring RICK J. MUNRO & STUART B. DALZIEL Department results from a set of visualization experiments conducted to analyse the hydrodynamic resuspension of particles from a thick horizontal sediment layer. The mechanism employed to produce the resuspension
Resuspension onset and crater erosion by a vortex ring interacting with a particle layer
Dalziel, Stuart
Resuspension onset and crater erosion by a vortex ring interacting with a particle layer N. Bethke://pof.aip.org/features/most_downloaded Information for Authors: http://pof.aip.org/authors #12;PHYSICS OF FLUIDS 24, 063301 (2012) Resuspension onset layer. The flow dynamics during the onset of particle resuspension are analysed using particle image
Sediment resuspension and erosion by vortex rings R. J. Munro,1,a
Dalziel, Stuart
Sediment resuspension and erosion by vortex rings R. J. Munro,1,a N. Bethke,2 and S. B. Dalziel2 1; accepted 26 January 2009; published online 8 April 2009 Particle resuspension and erosion induced-ring propagation speed. The critical conditions for resuspension whereby particles are only just resuspended were
Fluid Dynamics Research 33 (2003) 333356 Leapfrogging vortex rings: Hamiltonian structure, geometric
Shashikanth, Banavara N.
2003-01-01T23:59:59.000Z
Fluid Dynamics Research 33 (2003) 333356 Leapfrogging vortex rings: Hamiltonian structure that if the rings are modeled as coaxial circular ÿlaments, their dynamics and Hamil- tonian structure is derivable of Mechanical Engineering, New Mexico State University, Las Cruces, NM 88003, USA b Control and Dynamical
Vortex-peak interaction and lattice shape in rotating two-component Bose-Einstein condensates
Wei, Jun-cheng
Vortex-peak interaction and lattice shape in rotating two-component Bose-Einstein condensates: November 28, 2011) When a two component Bose-Einstein condensate is placed into rotation, a lattice component condensate is set into rotation, topological defects of both order parameters are created, which
Formation and Decay of Vortex Lattices in Bose-Einstein Condensates at Finite Temperatures
Formation and Decay of Vortex Lattices in Bose-Einstein Condensates at Finite Temperatures Gaseous Bose-Einstein condensates (BEC) are a testbed for many-body theory. Recently, rotating condensates was observed non-destructively by monitoring the centrifugal distortions of the rotating condensate
ccsd00003161, Vortex patterns in a fast rotating Bose-Einstein condensate
. Furthermore we restrict our analysis to the case of a two-dimensional gas in the xy plane, assumingccsdÂ00003161, version 1 Â 26 Oct 2004 Vortex patterns in a fast rotating Bose-Einstein condensate, France (Dated: October 26, 2004) For a fast rotating condensate in a harmonic trap, we investigate
Spacetime Defects von K\\'arm\\'an vortex street like configurations
Letelier, P S
2001-01-01T23:59:59.000Z
A special arrangement of spinning strings with dislocations similar to a von K\\'arm\\'an vortex street is studied. We numerically solve the geodesic equations for the special case of a test particle moving along twoinfinite rows of pure dislocations and also discuss the case of pure spinning defects.
Theory of vortex crystal formation in two-dimensional turbulence* Dezhe Z. Jin
California at San Diego, University of
Theory of vortex crystal formation in two-dimensional turbulence* Dezhe Z. Jin and Daniel H. E are symmetric arrays of strong vortices within a background of weaker vorticity. This paper presents a theory, a theory is advanced that allows us to predict from the initial conditions the approximate number
Joining of advanced materials by superplastic deformation
Goretta, Kenneth C. (Downers Grove, IL); Routbort, Jules L. (Hinsdale, IL); Gutierrez-Mora, Felipe (Woodridge, IL)
2008-08-19T23:59:59.000Z
A method for utilizing superplastic deformation with or without a novel joint compound that leads to the joining of advanced ceramic materials, intermetallics, and cermets. A joint formed by this approach is as strong as or stronger than the materials joined. The method does not require elaborate surface preparation or application techniques.
Deformation and Forming of Joined Materials
Carsley, John; Hovanski, Yuri; Clarke, Kester D.; Krajewski, Paul E.
2014-09-23T23:59:59.000Z
Introductory article to a set of invited papers from the TMS committee on shaping and forming. This paper introduces a set of papers that were prepared to discussing the deformation and forming of joined materials, and to announce an upcoming symposium at the 2015 MS&T meeting in Columbus Ohio.
FORMAL DEFORMATION THEORY 1. Introduction 1
de Jong, A. Johan
. Lifts of objects 50 17. Schlessinger's theorem on prorepresentable functors 52 18. Infinitesimal paper [TV10], which discusses deformation theory with groupoids but in less generality than we do here is one that satisfies the infinitesimal lifting criterion for objects, see Section 8. This is analogous
Experimental deformation of natural and synthetic dolomite
Davis, Nathan Ernest
2005-11-01T23:59:59.000Z
Natural and hot isostatically pressed dolomite aggregates were experimentally deformed at effective pressures of Pe = 50 ?? 400 MPa, temperatures of 400 ?? 850??C, and strain rates of ?& = 1.2x10-4 s-1 to 1.2x10-7 s-1. Coarse- and fine-grained...
Deformable Models & Applications Department of Computer Science
Duan, Ye
Deformable Models & Applications (Part I) Ye Duan Department of Computer Science University of Missouri at Columbia December 21, 2004 Ye Duan Department of Computer Science University of Missouri at Columbia December 21, 2004 University of Missouri at ColumbiaDepartment of Computer Science #12;Department
Damage and plastic deformation of reservoir rocks
Ze'ev, Reches
Damage and plastic deformation of reservoir rocks: Part 2. Propagation of a hydraulic fracture Seth fracture and fault mechanics, fluid flow in fractured reservoirs, and geome- chanics in nonconventional the development of complex hydraulic fractures (HFs) that are commonly ob- served in the field and in experiments
Tidal deformations of a spinning compact object
Paolo Pani; Leonardo Gualtieri; Andrea Maselli; Valeria Ferrari
2015-03-25T23:59:59.000Z
The deformability of a compact object induced by a perturbing tidal field is encoded in the tidal Love numbers, which depend sensibly on the object's internal structure. These numbers are known only for static, spherically-symmetric objects. As a first step to compute the tidal Love numbers of a spinning compact star, here we extend powerful perturbative techniques to compute the exterior geometry of a spinning object distorted by an axisymmetric tidal field to second order in the angular momentum. The spin of the object introduces couplings between electric and magnetic deformations and new classes of induced Love numbers emerge. For example, a spinning object immersed in a quadrupolar, electric tidal field can acquire some induced mass, spin, quadrupole, octupole and hexadecapole moments to second order in the spin. The deformations are encoded in a set of inhomogeneous differential equations which, remarkably, can be solved analytically in vacuum. We discuss certain subtleties in defining the multipole moments of the central object, which are due to the difficulty in separating the tidal field from the linear response of the object in the solution. By extending the standard procedure to identify the linear response in the static case, we prove analytically that the Love numbers of a Kerr black hole remain zero to second order in the spin. As a by-product, we provide the explicit form for a slowly-rotating, tidally-deformed Kerr black hole to quadratic order in the spin, and discuss its geodesic and geometrical properties.
On Lorentz Transformations in Symplectic Deformations
Cuesta, R.; Sabido, M. [Departamento de Fisica, DCI-Campus Leon, Universidad de Guanajuato, A.P. E-143, C.P. 37150, Guanajuato (Mexico); Guzman, W. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21945-970, Rio de Janeiro (Brazil)
2010-07-12T23:59:59.000Z
In this paper we study noncommutative Lorentz transformations using symplectic deformations. In this framework we define an infinitesimal line element that is invariant under this noncommutative Lorentz transformations. Using the symplectic geometry formalism, we find that noncommutative Lorentz transformations intertwine the canonical momentums with canonical position coordinates.
Deformable Transparent All-Carbon-Nanotube Transistors
Maruyama, Shigeo
and organic materials16,17 are candidates for next-generation flexible and transparent electronic devices-carbon-nanotube field-effect transistors (CNT- FETs), making use of the flexible yet robust nature of single than those used in other flexible CNT-FETs allowed our devices to be highly deformable without
Mesh Puppetry: Cascading Optimization of Mesh Deformation with Inverse Kinematics
Desbrun, Mathieu
approach builds upon traditional rigging by optimizing skeleton position and vertex weights. Keywords: Mesh deformation, nonlinear optimization, inverse kinematics, geometry processing. 1 Introduction. To allow for more global and complex deforma- tion, many authors proposed to cast mesh deformation
Deformability of Plasmodium falciparum parasitized red blood cells
Mills, John Philip, Ph. D. Massachusetts Institute of Technology
2007-01-01T23:59:59.000Z
The biophysical properties of the human red blood cell (RBC) permit large deformations required for passage through narrow capillaries and spleen sinusoids. Several pathologic conditions alter RBC deformability that can ...
Effects of cryogenic equal channel angular deformation on copper 101
Horan, Christopher Sean
2001-01-01T23:59:59.000Z
101 was cold worked by being subjected to severe plastic deformation (SPD) at room temperature (23 °C) and at -196 °C under liquid nitrogen. Cold working was imparted by equal channel angular deformation (ECAD). Before extrusions were performed, a...
Effects of subsurface fracture interactions on surface deformation
Jerry, Ruel (Ruel Valentine)
2013-01-01T23:59:59.000Z
Although the surface deformation resulting from the opening of a single fracture in a layered elastic half-space resembles the observed deformation at the InSalah site, it seems unlikely that only a single fracture is ...
Severe plastic deformation of difficult-to-work alloys
Yapici, Guney Guven
2004-09-30T23:59:59.000Z
The present work aims to reveal the microstructural evolution and post-processing mechanical behavior of difficult-to-work alloys upon severe plastic deformation. Severe plastic deformation is applied using equal channel angular extrusion (ECAE...
Gelcasting Alumina Cores for Investment Casting
Janney, M A; Klug, F J
2001-01-01T23:59:59.000Z
General Electric currently uses silica investment casting cores for making superalloy turbine blades. The silica core technology does not provide the degree of dimensional control needed for advanced turbine system manufacture. The sum of the various process variables in silica core manufacturing produces cores that have more variability than is allowed for in advanced, power-generation gas turbine airfoils.
q-deformed logistic map with delay feedback
Manish Dev Shrimali; Subhashish Banerjee
2012-03-14T23:59:59.000Z
The delay logistic map with two types of q-deformations: Tsallis and Quantum-group type are studied. The stability of the map and its bifurcation scheme is analyzed as a function of the deformation and delay feedback parameters. Chaos is suppressed in a certain region of deformation and feedback parameter space. The steady state obtained by delay feedback is maintained in one type of deformation while chaotic behavior is recovered in another type with increasing delay.
Intrinsic Shapes of Molecular Cloud Cores
C. E. Jones; Shantanu Basu; John Dubinski
2001-01-08T23:59:59.000Z
We conduct an analysis of the shapes of molecular cloud cores using recently compiled catalogs of observed axis ratios of individual cores mapped in ammonia or through optical selection. We apply both analytical and statistical techniques to deproject the observed axis ratios in order to determine the true distribution of cloud core shapes. We find that neither pure oblate nor pure prolate cores can account for the observed distribution of core shapes. Intrinsically triaxial cores produce distributions which agree with observations. The best-fit triaxial distribution contains cores which are more nearly oblate than prolate.
Grain alignment in starless cores
Jones, T. J.; Bagley, M. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Krejny, M. [Cree Inc., 4600 Silicon Dr., Durham, NC (United States); Andersson, B.-G. [SOFIA Science Center, USRA, Moffett Field, CA (United States); Bastien, P., E-mail: tjj@astro.umn.edu [Centre de recherche en astrophysique du Québec and Départment de Physique, Université de Montréal, Montréal (Canada)
2015-01-01T23:59:59.000Z
We present near-IR polarimetry data of background stars shining through a selection of starless cores taken in the K band, probing visual extinctions up to A{sub V}?48. We find that P{sub K}/?{sub K} continues to decline with increasing A{sub V} with a power law slope of roughly ?0.5. Examination of published submillimeter (submm) polarimetry of starless cores suggests that by A{sub V}?20 the slope for P versus ? becomes ??1, indicating no grain alignment at greater optical depths. Combining these two data sets, we find good evidence that, in the absence of a central illuminating source, the dust grains in dense molecular cloud cores with no internal radiation source cease to become aligned with the local magnetic field at optical depths greater than A{sub V}?20. A simple model relating the alignment efficiency to the optical depth into the cloud reproduces the observations well.
Reactor core isolation cooling system
Cooke, Franklin E. (San Jose, CA)
1992-01-01T23:59:59.000Z
A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom.
Reactor core isolation cooling system
Cooke, F.E.
1992-12-08T23:59:59.000Z
A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom. 1 figure.
Core-melt source reduction system
Forsberg, C.W.; Beahm, E.C.; Parker, G.W.
1995-04-25T23:59:59.000Z
A core-melt source reduction system for ending the progression of a molten core during a core-melt accident and resulting in a stable solid cool matrix. The system includes alternating layers of a core debris absorbing material and a barrier material. The core debris absorbing material serves to react with and absorb the molten core such that containment overpressurization and/or failure does not occur. The barrier material slows the progression of the molten core debris through the system such that the molten core has sufficient time to react with the core absorbing material. The system includes a provision for cooling the glass/molten core mass after the reaction such that a stable solid cool matrix results. 4 figs.
Core-melt source reduction system
Forsberg, Charles W. (Oak Ridge, TN); Beahm, Edward C. (Oak Ridge, TN); Parker, George W. (Concord, TN)
1995-01-01T23:59:59.000Z
A core-melt source reduction system for ending the progression of a molten core during a core-melt accident and resulting in a stable solid cool matrix. The system includes alternating layers of a core debris absorbing material and a barrier material. The core debris absorbing material serves to react with and absorb the molten core such that containment overpressurization and/or failure does not occur. The barrier material slows the progression of the molten core debris through the system such that the molten core has sufficient time to react with the core absorbing material. The system includes a provision for cooling the glass/molten core mass after the reaction such that a stable solid cool matrix results.
Competitive Mixture of Deformable Models for Pattern Classification \\Lambda
Yeung, Dit-Yan
Competitive Mixture of Deformable Models for Pattern Classification \\Lambda KwokÂWai Cheung Dit to pattern classification. Recently, we have cast a deformable model under a Bayesian framework for classification, giving promising results. However, deformable model methods are computationÂ ally expensive due
Quantum Logic Gates using q-deformed Oscillators
Debashis Gangopadhyay; Mahendra Nath Sinha Roy
2006-07-14T23:59:59.000Z
We show that the quantum logic gates, {\\it viz.} the single qubit Hadamard and Phase Shift gates, can also be realised using q-deformed angular momentum states constructed via the Jordan-Schwinger mechanism with two q-deformed oscillators. {\\it Keywords :} quantum logic gates ; q-deformed oscillators ; quantum computation {\\it PACS:} 03.67.Lx ; 02.20.Uw
Partitioning a Deformed Urban Grid Leonard Hagger Ian Sanders
Wismath, Stephen
a convex map of the deformed urban grid. These algorithms are very similar and would #12;nd the same convex map of any given deformed urban grid. In this research I present two di#11;erent algorithms to solve this problem. Both are shown to #12;nd a signi#12;cantly better convex map of the deformed urban grid. The #12
Fractures in oriented Devonian-shale cores from the Appalachian Basin. Vol. 1
Evans, M.A.
1980-01-01T23:59:59.000Z
Examination of thirteen oriented Devonian-shale cores from the Appalachian Basin revealed considerable fracturing and shearing at depth. Fracture frequency and orientation measurements were made on the fractures in each core. Fractures and associated structures were differentiated into core-induced fractures, unmineralized natural fractures, mineralized natural fractures, slickensided fractures, and slickenlines. Core-induced fractures exhibit a consistent northeast orientation both areally and with depth. This consistency indicates the presence of an anisotropy which is interpreted to be related to an east to northeast trending maximum compressive stress developed in eastern North America by the convective flow in the mantle associated with spreading along the Mid-Atlantic Ridge. Natural fracture, slickenside, and slickenline orientations are related to: (1) northwest directed tectonic compressive stresses associated with Alleghenian deformation, (2) stresses associated with local faulting, and (3) the same east to northeast maximum compressive stress responsible for the core-induced fractures. Higher frequencies of natural fractures and slickensides are associated primarily with incompetent, high-organic shales. Natural fractures occur most frequently in the Marcellus Shale, Tully Limestone, Geneseo Shale, West Falls Formation, and the Lower Huron Member of the Ohio Shale. Slickensided fractures occur most frequently in the Marcellus Shale, Tully Limestone, Geneseo Shale, West Falls Formation, base of the Java Formation, and Lower Huron and Cleveland Members of the Ohio Shale. These observations are consistent with a fracture facies concept that proposes fracture development in shales that have acted as decollement zones during Alleghenian deformation. Detailed reports are included in Volume 2 for each of the thirteen cores investigated. 25 figures, 4 tables.
Massive Quiescent Cores in Orion. -- II. Core Mass Function
Li, D; Goldsmith, P F; Langer, W D
2006-01-01T23:59:59.000Z
We have surveyed submillimeter continuum emission from relatively quiescent regions in the Orion molecular cloud to determine how the core mass function in a high mass star forming region compares to the stellar initial mass function. Such studies are important for understanding the evolution of cores to stars, and for comparison to formation processes in high and low mass star forming regions. We used the SHARC II camera on the Caltech Submillimeter Observatory telescope to obtain 350 \\micron data having angular resolution of about 9 arcsec, which corresponds to 0.02 pc at the distance of Orion. Our analysis combining dust continuum and spectral line data defines a sample of 51 Orion molecular cores with masses ranging from 0.1 \\Ms to 46 \\Ms and a mean mass of 9.8 \\Ms, which is one order of magnitude higher than the value found in typical low mass star forming regions, such as Taurus. The majority of these cores cannot be supported by thermal pressure or turbulence, and are probably supercritical.They are th...
Kansalliskirjasto Dublin Core Dublin Core metadataformaatin suomalainen versio
Rodriguez, Carlos
- Medical Subject Headings 3. DDC - Dewey Decimal Classification 4. LCC - Library of Congress Classification: - Merkintäjärjestelmät: #12;Kansalliskirjasto Dublin Core 2(6) 1. LCSH - Library of Congress Subject Headings 2. MESH 5. UDC - Universal Decimal Classification Suomalaiset merkintäjärjestelmät katso sfs_aihe.pdf Kuvaus
Core Values | The Ames Laboratory
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration would likeConstitution AndControllingCool MagneticCoos BayCore FileCore
Laminated grid and web magnetic cores
Sefko, John (Monroeville, PA); Pavlik, Norman M. (Plum Borough, PA)
1984-01-01T23:59:59.000Z
A laminated magnetic core characterized by an electromagnetic core having core legs which comprise elongated apertures and edge notches disposed transversely to the longitudinal axis of the legs, such as high reluctance cores with linear magnetization characteristics for high voltage shunt reactors. In one embodiment the apertures include compact bodies of microlaminations for more flexibility and control in adjusting permeability and/or core reluctance.
Schlegel, Fabrice
Using high-resolution 3-D vortex simulations, this study seeks a mechanistic understanding of vorticity dynamics in transverse jets at a finite Reynolds number. A full no-slip boundary condition, rigorously formulated in ...
A Search for Channel Deformation in Irradiated Vanadium Tensile Specimens
Gelles, David S.; Toloczko, Mychailo B.; Kurtz, Richard J.
2010-02-26T23:59:59.000Z
A miniature tensile specimen of V-4Cr-4Ti which had be irradiated in the 17J test at 425°C to 3.7 dpa was mechanically polished, deformed to 3.9% strain at room temperature, and examined by scanning and transmission electron microscopy in order to look for evidence of channel deformation. It was found that uniform deformation can occur without channel deformation, but evidence for channeling was found with channels appearing most prominently after the onset of necking. The channeling occurs on wavy planes with large variations in localized deformation from channel to channel.
Large core fiber optic cleaver
Halpin, J.M.
1996-03-26T23:59:59.000Z
The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 {micro}m. 30 figs.
Large core fiber optic cleaver
Halpin, John M. (Livermore, CA)
1996-01-01T23:59:59.000Z
The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 .mu.m.
Stability of Molten Core Materials
Layne Pincock; Wendell Hintze
2013-01-01T23:59:59.000Z
The purpose of this report is to document a literature and data search for data and information pertaining to the stability of nuclear reactor molten core materials. This includes data and analysis from TMI-2 fuel and INL’s LOFT (Loss of Fluid Test) reactor project and other sources.
Miyamoto, K., E-mail: k-miyamoto@faculty.chiba-u.jp [Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Suizu, K.; Akiba, T. [Department of Electrical, Electronics and Computer Engineering, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016 (Japan); Omatsu, T. [Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); CREST Japan Science and Technology Agency, Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan)
2014-06-30T23:59:59.000Z
A terahertz (THz) spiral phase plate with high transmission (>90% after Fresnel correction) and low dispersion has been developed based on the Tsurupica olefin polymer. Direct observations of the topological charge (both magnitude and sign) of a THz vortex beam are performed by using a THz camera with tilted lens focusing and radial defect introduction. The vortex outputs with a topological charge of ±1 (or ±2) are obtained at a frequency of 2 (or 4) THz.
Logging-while-coring method and apparatus
Goldberg, David S.; Myers, Gregory J.
2007-01-30T23:59:59.000Z
A method and apparatus for downhole coring while receiving logging-while-drilling tool data. The apparatus includes core collar and a retrievable core barrel. The retrievable core barrel receives core from a borehole which is sent to the surface for analysis via wireline and latching tool The core collar includes logging-while-drilling tools for the simultaneous measurement of formation properties during the core excavation process. Examples of logging-while-drilling tools include nuclear sensors, resistivity sensors, gamma ray sensors, and bit resistivity sensors. The disclosed method allows for precise core-log depth calibration and core orientation within a single borehole, and without at pipe trip, providing both time saving and unique scientific advantages.
Logging-while-coring method and apparatus
Goldberg, David S. (New York, NY); Myers, Gregory J. (Cornwall, NY)
2007-11-13T23:59:59.000Z
A method and apparatus for downhole coring while receiving logging-while-drilling tool data. The apparatus includes core collar and a retrievable core barrel. The retrievable core barrel receives core from a borehole which is sent to the surface for analysis via wireline and latching tool The core collar includes logging-while-drilling tools for the simultaneous measurement of formation properties during the core excavation process. Examples of logging-while-drilling tools include nuclear sensors, resistivity sensors, gamma ray sensors, and bit resistivity sensors. The disclosed method allows for precise core-log depth calibration and core orientation within a single borehole, and without at pipe trip, providing both time saving and unique scientific advantages.
Evolution of deformations in medium-mass nuclei
H. Sagawa; X. R. Zhou; X. Z. Zhang
2005-10-28T23:59:59.000Z
Evolution of quadrupole deformations in $sd$ and $pf$ shell nuclei with mass A= 18$\\sim$56 is studied by using deformed Skyrme Hartree-Fock (HF) model with pairing correlations. We point out that the quadrupole deformations of the nuclei with the isospin T=0 and T=1 show strong mass number dependence as a clear manifestation of dynamical evolution of deformation in nuclear many-body systems. The competition between the deformation driving particle-vibration coupling and the closed shell structure is shown in a systematic study of the ratios between the proton and neutron deformations in nuclei with T=$|$T$_z|$=1. Calculated quadrupole and hexadecapole deformations are compared with shell model results and available experimental data. A relation between the skin thickness and the intrinsic Q$_2$ moments is also discussed.
Biaxially textured articles formed by plastic deformation
Goyal, Amit (Knoxville, TN)
2001-01-01T23:59:59.000Z
A method of preparing a biaxially textured article comprises the steps of providing a metal preform, coating or laminating the preform with a metal layer, deforming the layer to a sufficient degree, and rapidly recrystallizing the layer to produce a biaxial texture. A superconducting epitaxial layer may then be deposited on the biaxial texture. In some embodiments the article further comprises buffer layers, electromagnetic devices or electro-optical devices.
The Minimal Geometric Deformation Approach Extended
Casadio, Roberto; da Rocha, Roldao
2015-01-01T23:59:59.000Z
The minimal geometric deformation approach was introduced in order to study the exterior space-time around spherically symmetric self-gravitating systems, like stars or similar astrophysical objects as well, in the Randall-Sundrum brane-world framework. A consistent extension of this approach is developed here, which contains modifications of both the time component and the radial component of a spherically symmetric metric. A modified Schwarzschild geometry is obtained as an example of its simplest application.
${\\cal D}$-deformed harmonic oscillators
F. Bagarello; F. Gargano; D. Volpe
2014-12-30T23:59:59.000Z
We analyze systematically several deformations arising from two-dimensional harmonic oscillators which can be described in terms of $\\cal{D}$-pseudo bosons. They all give rise to exactly solvable models, described by non self-adjoint hamiltonians whose eigenvalues and eigenvectors can be found adopting the quite general framework of the so-called $\\cal{D}$-pseudo bosons. In particular, we show that several models previously introduced in the literature perfectly fit into this scheme.
Hibbs, R.; Chen, Y.; Nikitopoulos, D. [Louisiana State Univ., Baton Rouge, LA (United States)] [and others
1995-10-01T23:59:59.000Z
The effect of vortex generators on the mass (heat) transfer from the ribbed passage of a two pass turbine blade coolant channel is investigated with the intent of optimizing the vortex generator geometry so that significant enhancements in mass/heat transfer can be achieved. In the experimental configuration considered, ribs are mounted on two opposite walls; all four walls along each pass are active and have mass transfer from their surfaces but the ribs are non-participating. Mass transfer measurements, in the form of Sherwood number ratios, are made along the centerline and in selected inter-rib modules. Results are presented for Reynolds number in the range of 5,000 to 40,000, pitch to rib height ratios of 10.5 and 21, and vortex generator-rib spacing to rib height ratios of 0.55, and 1.5. Centerline and spanwise averaged Sherwood number ratios are presented along with contours of the Sherwood number ratios. Results indicate that the vortex generators induce substantial increases in the local mass transfer rates, particularly along the side walls, and modest increases in the average mass transfer rates. The vortex generators have the effect of making the inter-rib profiles along the ribbed walls more uniform. Along the side walls, horse-shoe vortices that characterize the vortex generator wake are associated with significant mass transfer enhancements. The wake effects and the levels of enhancement decrease somewhat with increasing Reynolds number and decreasing pitch.
Hibbs, R.; Acharya, S.; Chen, Y. [Louisiana State Univ., Baton Rouge, LA (United States)] [and others
1995-12-31T23:59:59.000Z
The effect of vortex generators on the mass (heat) transfer from the ribbed passage of a two pass turbine blade coolant channel is investigated with the intent of optimizing the vortex generator geometry so that significant enhancements in mass/heat transfer can be achieved. In the experimental configuration considered, ribs are mounted on two opposite walls; all four walls along each pass are active and have mass transfer from their surfaces but the ribs are non-participating. Mass transfer measurements, in the form of Sherwood number ratios, are made along the centerline and in selected inter-rib modules. Results are presented for Reynolds number in the range of 5,000 to 40,000, pitch to rib height ratios of 10.5 and 21, and vortex generator-rib spacing to rib height ratios of 0.55, and 1.5. Centerline and spanwise averaged Sherwood number ratios are presented along with contours of the Sherwood number ratios. Results indicate that the vortex generators induce substantial increases in the local mass transfer rates, particularly along the side walls, and modest increases in the average mass transfer rates. The vortex generators have the effect of making the inter-rib profiles along the ribbed walls more uniform. Along the side walls, horse-shoe vortices that characterize the vortex generator wake are associated with significant mass transfer enhancements. The wake effects and the levels of enhancement decrease somewhat with increasing Reynolds number and decreasing pitch.
Hibbs, R.G.; Acharya, S.; Chen, Y.; Nikitopoulos, D.E.; Myrum, T.A. [Louisiana State Univ., Baton Rouge, LA (United States). Mechanical Engineering Dept.
1998-07-01T23:59:59.000Z
The effect of vortex generators on the mass (heat) transfer from the ribbed passage of a two-pass turbine blade coolant channel is investigated with the intent of optimizing the vortex generator geometry so that significant enhancements in mass/heat transfer can be achieved. In the experimental configuration considered, ribs are mounted on two opposite walls; all four walls along each pass are active and have mass transfer from their surfaces but the ribs are nonparticipating. Mass transfer measurements, in the form of Sherwood number ratios, are made along the centerline and in selected interrib modules. Results are presented for Reynolds number in the range of 5000 to 40,000 pitch to rib height ratios of 10.5 and 21, and vortex generator-rib spacing to rib height ratios of 0.55 and 1.5. Centerline and spanwise-averaged Sherwood number ratios are presented along with contours of the Sherwood number ratios. Results indicate that the vortex generators lead to substantial increases in the local mass transfer rates, particularly along the side walls, and modest increases in the average mass transfer rates. The vortex generators have the effect of making the interrib profiles along the ribbed walls more uniform. Along the side walls, vortices that characterize the vortex generator wake are associated with significant mass transfer enhancements. The wake effects and the levels of enhancement decrease somewhat with increasing Reynolds number and decreasing pitch.
Van Gorder, Robert A., E-mail: rav@knights.ucf.edu [Department of Mathematics, University of Central Florida, Orlando, Florida 32816-1364 (United States)
2014-06-15T23:59:59.000Z
In his study of superfluid turbulence in the low-temperature limit, Svistunov [“Superfluid turbulence in the low-temperature limit,” Phys. Rev. B 52, 3647 (1995)] derived a Hamiltonian equation for the self-induced motion of a vortex filament. Under the local induction approximation (LIA), the Svistunov formulation is equivalent to a nonlinear dispersive partial differential equation. In this paper, we consider a family of rotating vortex filament solutions for the LIA reduction of the Svistunov formulation, which we refer to as the 2D LIA (since it permits a potential formulation in terms of two of the three Cartesian coordinates). This class of solutions holds the well-known Hasimoto-type planar vortex filament [H. Hasimoto, “Motion of a vortex filament and its relation to elastica,” J. Phys. Soc. Jpn. 31, 293 (1971)] as one reduction and helical solutions as another. More generally, we obtain solutions which are periodic in the space variable. A systematic analytical study of the behavior of such solutions is carried out. In the case where vortex filaments have small deviations from the axis of rotation, closed analytical forms of the filament solutions are given. A variety of numerical simulations are provided to demonstrate the wide range of rotating filament behaviors possible. Doing so, we are able to determine a number of vortex filament structures not previously studied. We find that the solution structure progresses from planar to helical, and then to more intricate and complex filament structures, possibly indicating the onset of superfluid turbulence.
A shapeable material without plastic deformation
Naomi Oppenheimer; Thomas A. Witten
2015-05-06T23:59:59.000Z
Randomly crumpled sheets have shape memory. In order to understand the basis of this form of memory, we simulate triangular lattices of springs whose lengths are altered to create a topography with multiple potential energy minima. We then deform these lattices into different shapes and investigate their ability to retain the imposed shape when the energy is relaxed. The lattices are able to retain a range of curvatures. Under moderate forcing from a state of local equilibrium, the lattices deform by several percent but return to their retained shape when the forces are removed. By increasing the forcing until an irreversible motion occurs, we find that the transitions between remembered shapes show co-operativity among several springs. For fixed lattice structures, the shape memory tends to decrease as the lattice is enlarged; we propose ways to counter this decrease by modifying the lattice geometry. We survey the energy landscape by displacing individual nodes. An extensive fraction of these nodes proves to be bistable; they retain their displaced position when the energy is relaxed. Bending the lattice to a stable curved state alters the pattern of bistable nodes. We discuss this shapeability in the context of other forms of material memory and contrast it with the shapeability of plastic deformation. We outline the prospects for making real materials based on these principles.
q-Deformed KP Hierarchy and q-Deformed Constrained KP Hierarchy
Jingsong He; Yinghua Li; Yi Cheng
2006-06-15T23:59:59.000Z
Using the determinant representation of gauge transformation operator, we have shown that the general form of $\\tau$ function of the $q$-KP hierarchy is a q-deformed generalized Wronskian, which includes the q-deformed Wronskian as a special case. On the basis of these, we study the q-deformed constrained KP ($q$-cKP) hierarchy, i.e. $l$-constraints of $q$-KP hierarchy. Similar to the ordinary constrained KP (cKP) hierarchy, a large class of solutions of $q$-cKP hierarchy can be represented by q-deformed Wronskian determinant of functions satisfying a set of linear $q$-partial differential equations with constant coefficients. We obtained additional conditions for these functions imposed by the constraints. In particular, the effects of $q$-deformation ($q$-effects) in single $q$-soliton from the simplest $\\tau$ function of the $q$-KP hierarchy and in multi-$q$-soliton from one-component $q$-cKP hierarchy, and their dependence of $x$ and $q$, were also presented. Finally, we observe that $q$-soliton tends to the usual soliton of the KP equation when $x\\to 0$ and $q\\to 1$, simultaneously.
Extended core for motor/generator
Shoykhet, Boris A.
2005-05-10T23:59:59.000Z
An extended stator core in a motor/generator can be utilized to mitigate losses in end regions of the core and a frame of the motor/generator. To mitigate the losses, the stator core can be extended to a length substantially equivalent to or greater than a length of a magnetically active portion in the rotor. Alternatively, a conventional length stator core can be utilized with a shortened magnetically active portion to mitigate losses in the motor/generator. To mitigate the losses in the core caused by stator winding, the core can be extended to a length substantially equivalent or greater than a length of stator winding.
Extended core for motor/generator
Shoykhet, Boris A.
2006-08-22T23:59:59.000Z
An extended stator core in a motor/generator can be utilized to mitigate losses in end regions of the core and a frame of the motor/generator. To mitigate the losses, the stator core can be extended to a length substantially equivalent to or greater than a length of a magnetically active portion in the rotor. Alternatively, a conventional length stator core can be utilized with a shortened magnetically active portion to mitigate losses in the motor/generator. To mitigate the losses in the core caused by stator winding, the core can be extended to a length substantially equivalent or greater than a length of stator winding.
Dussaux, A.; Rache Salles, B.; Jenkins, A. S.; Bortolotti, P.; Grollier, J.; Cros, V.; Fert, A. [Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France); Grimaldi, E., E-mail: eva.grimaldi@thalesgroup.com [Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France); CNES, 1 Avenue Edouard Belin, 31400 Toulouse (France); Khvalkovskiy, A. V. [Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France); A.M. Prokhorov General Physics Institute of RAS, Vavilova Str. 38, 119991 Moscow (Russian Federation); Kubota, H.; Fukushima, A.; Yakushiji, K.; Yuasa, S. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan)
2014-07-14T23:59:59.000Z
We investigate the microwave response of a spin transfer vortex based oscillator in a magnetic tunnel junction with an in-plane reference layer combined with a spin valve with an out-of-plane magnetization spin polarizing layer. The main advantage of this perpendicular spin polarizer is to induce a large spin transfer force even at zero magnetic field, thus leading to a record emitted power (up to 0.6??W) associated to a very narrow spectral linewidth of a few hundreds of kHz. The characteristics of this hybrid vortex based spin transfer nano-oscillator obtained at zero field and room temperature are of great importance for applications based on rf spintronic devices as integrated and tunable microwave source and/or microwave detector.
Von K\\'arm\\'an Vortex Street within an Impacting Drop
Thoraval, Marie-Jean; Etoh, Takeharu Goji; Popinet, Stephane; Ray, Pascal; Josserand, Christophe; Zaleski, Stephane; Thoroddsen, Sigurdur
2012-01-01T23:59:59.000Z
The splashing of a drop impacting onto a liquid pool produces a range of different sized micro-droplets. At high impact velocities, the most significant source of these droplets is a thin liquid jet emerging at the start of the impact from the neck that connects the drop to the pool. We use ultra-high-speed video imaging in combination with high-resolution numerical simulations to show how the ejecta gives way to irregular splashing. At higher Reynolds number, its base becomes unstable, shedding vortex rings into the liquid from the free surface in an axisymmetric von K\\'arm\\'an vortex street, thus breaking the ejecta sheet as it forms.
Analytical Tendex and Vortex Fields for Perturbative Black Hole Initial Data
Kenneth A. Dennison; Thomas W. Baumgarte
2012-07-10T23:59:59.000Z
Tendex and vortex fields, defined by the eigenvectors and eigenvalues of the electric and magnetic parts of the Weyl curvature tensor, form the basis of a recently developed approach to visualizing spacetime curvature. In particular, this method has been proposed as a tool for interpreting results from numerical binary black hole simulations, providing a deeper insight into the physical processes governing the merger of black holes and the emission of gravitational radiation. Here we apply this approach to approximate but analytical initial data for both single boosted and binary black holes. These perturbative data become exact in the limit of small boost or large binary separation. We hope that these calculations will provide additional insight into the properties of tendex and vortex fields, and will form a useful test for future numerical calculations.
Tripolar vortex formation in dense quantum plasma with ion-temperature-gradients
Qamar, Anisa; Ata-ur-Rahman [Institute of Physics and Electronics, University of Peshawar, Khyber Pakhtoon Khwa 25000 (Pakistan); National Center for Physics Shahdrah Valley Road, Islamabad 44000 (Pakistan); Mirza, Arshad M. [Theoretical Plasma Physics Group, Physics Department, Quaid-i-Azam University, Islamabad 45320 (Pakistan)
2012-05-15T23:59:59.000Z
We have derived system of nonlinear equations governing the dynamics of low-frequency electrostatic toroidal ion-temperature-gradient mode for dense quantum magnetoplasma. For some specific profiles of the equilibrium density, temperature, and ion velocity gradients, the nonlinear equations admit a stationary solution in the form of a tripolar vortex. These results are relevant to understand nonlinear structure formation in dense quantum plasmas in the presence of equilibrium ion-temperature and density gradients.
Under consideration for publication in J. Fluid Mech. 1 Three-dimensional vortex dynamics in
Pawlak, Geno
, the boundary layer can become centrifugally unstable (Honji 1981), leading to well-developed G¨ortler vortices dissipation and boundary layer dynamics. It is widely accepted that vortex shedding is a dominant pr in oscillatory flow separation M I G U E L C A N A L S AND G E N O P A W L A K Department of Ocean and Resources
Vortex free energy and deconfinement in center-blind discretizations of Yang-Mills theories
Burgio, G; Kerler, W; Müller-Preussker, M
2006-01-01T23:59:59.000Z
Maximal 't Hooft loops are studied in SO(3) lattice gauge theory at finite temperature T. Tunneling barriers among twist sectors causing loss of ergodicity for local update algorithms are overcome through parallel tempering, enabling us to measure the vortex free energy F and to identify a deconfinement transition at some $\\beta_A^{crit}$. The behavior of F below $\\beta_A^{crit}$ shows however striking differences with what is expected from discretizations in the fundamental representation.
EARLY EVOLUTION OF PRESTELLAR CORES
Horedt, G. P., E-mail: g.horedt@online.de [Kronwinkler 50, D-81245, Munich (Germany)
2013-08-20T23:59:59.000Z
Prestellar cores are approximated by singular polytropic spheres. Their early evolution is studied analytically with a Bondi-like scheme. The considered approximation is meaningful for polytropic exponents {gamma} between 0 and 6/5, implying radial power-law density profiles between r {sup -1} and r {sup -2.5}. Gravitationally unstable Jeans and Bonnor-Ebert masses differ at most by a factor of 3.25. Tidally stable prestellar cores must have a mean density contrast {approx}> 8 with respect to the external parent cloud medium. The mass-accretion rate relates to the cube of equivalent sound speed, as in Shu's seminal paper. The prestellar masses accreted over 10{sup 5} years cover the whole stellar mass spectrum; they are derived in simple closed form, depending only on the polytropic equation of state. The stellar masses that can be formed via strict conservation of angular momentum are at most of the order of a brown dwarf.
Processing of Activated Core Components
Friske, A.; Gestermann, G.; Finkbeiner, R.
2003-02-26T23:59:59.000Z
Used activated components from the core of a NPP like control elements, water channels from a BWR, and others like in-core measurement devices need to be processed into waste forms suitable for interim storage, and for the final waste repository. Processing of the activated materials can be undertaken by underwater cutting and packaging or by cutting and high-pressure compaction in a hot cell. A hot cell is available in Germany as a joint investment between GNS and the Karlsruhe Research Center at the latter's site. Special transport equipment is available to transport the components ''as-is'' to the hot cell. Newly designed underwater processing equipment has been designed, constructed, and operated for the special application of NPP decommissioning. This equipment integrates an underwater cutting device with an 80 ton force underwater in-drum compactor.
Towards quantum noncommutative {kappa}-deformed field theory
Daszkiewicz, Marcin; Lukierski, Jerzy; Woronowicz, Mariusz [Institute of Theoretical Physics, University of Wroclaw pl. Maxa Borna 9, 50-206 Wroclaw (Poland)
2008-05-15T23:59:59.000Z
We introduce a new {kappa}-star product describing the multiplication of quantized {kappa}-deformed free fields. The {kappa} deformation of local free quantum fields originates from two sources: noncommutativity of space-time and the {kappa} deformation of field oscillators algebra; we relate these two deformations. We demonstrate that for a suitable choice of {kappa}-deformed field oscillators algebra, the {kappa}-deformed version of the microcausality condition is satisfied, and it leads to the deformation of the Pauli-Jordan commutation function defined by the {kappa}-deformed mass shell. We show by constructing the {kappa}-deformed Fock space that the use of the {kappa}-deformed oscillator algebra permits one to preserve the bosonic statistics of n-particle states. The proposed star product is extended to the product of n fields, which for n=4 defines the interaction vertex in perturbative description of the noncommutative quantum {lambda}{phi}{sup 4} field theory. It appears that the classical four-momentum conservation law is satisfied at the interaction vertices.
Laminated electromagnetic pump stator core
Fanning, A.W.
1995-08-08T23:59:59.000Z
A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference. This pump is used in nuclear fission reactors. 19 figs.
TMI-2 core shipping preparations
Ball, L.J.; (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Barkanic, R.J. (Bechtel North American Power Corporation (United States)); Conaway, W.T. II (GPU Nuclear Corporation, Three Mile Island, Middletown, PA (United States)); Schmoker, D.S. (Nuclear Packaging, Inc., Federal Way, WA (United States))
1988-01-01T23:59:59.000Z
Shipping the damaged core from the Unit 2 reactor of Three Mile Island Nuclear Power Station near Harrisburg, PA, to the Idaho National Engineering Laboratory near Idaho Falls, ID, required development and implementation of a completely new spent fuel transportation system. This paper describes the equipment developed, the planning and activities used to implement the hardware systems into the facilities, and the planning involved in making the rail shipments. It also includes a summary of recommendations resulting from this experience.
False Vacuum Lumps with the Fermionic Core
Yutaka Hosotani; Ramin G. Daghigh
2004-01-30T23:59:59.000Z
Stable gravitating lumps with a false vacuum core surrounded by the true vacuum in a scalar field potential exist in the presence of fermions at the core. These objects may exist in the universe at various scales.
Scaling Turbo Boost to a 1000 cores
S, Ananth Narayan; Fedorova, Alexandra
2010-01-01T23:59:59.000Z
The Intel Core i7 processor code named Nehalem provides a feature named Turbo Boost which opportunistically varies the frequencies of the processor's cores. The frequency of a core is determined by core temperature, the number of active cores, the estimated power consumption, the estimated current consumption, and operating system frequency scaling requests. For a chip multi-processor(CMP) that has a small number of physical cores and a small set of performance states, deciding the Turbo Boost frequency to use on a given core might not be difficult. However, we do not know the complexity of this decision making process in the context of a large number of cores, scaling to the 100s, as predicted by researchers in the field.
Coring in deep hardrock formations
Drumheller, D.S.
1988-08-01T23:59:59.000Z
The United States Department of Energy is involved in a variety of scientific and engineering feasibility studies requiring extensive drilling in hard crystalline rock. In many cases well depths extend from 6000 to 20,000 feet in high-temperature, granitic formations. Examples of such projects are the Hot Dry Rock well system at Fenton Hill, New Mexico and the planned exploratory magma well near Mammoth Lakes, California. In addition to these programs, there is also continuing interest in supporting programs to reduce drilling costs associated with the production of geothermal energy from underground sources such as the Geysers area near San Francisco, California. The overall progression in these efforts is to drill deeper holes in higher temperature, harder formations. In conjunction with this trend is a desire to improve the capability to recover geological information. Spot coring and continuous coring are important elements in this effort. It is the purpose of this report to examine the current methods used to obtain core from deep wells and to suggest projects which will improve existing capabilities. 28 refs., 8 figs., 2 tabs.
Development of integrated core disruptive accident analysis code for FBR - ASTERIA-FBR
Ishizu, T.; Endo, H.; Tatewaki, I.; Yamamoto, T. [Japan Nuclear Energy Safety Organization JNES, Toranomon Towers Office, 4-1-28, Toranomon, Minato-ku, Tokyo (Japan); Shirakawa, N. [Inst. of Applied Energy IAE, Shimbashi SY Bldg., 14-2 Nishi-Shimbashi 1-Chome, Minato-ku, Tokyo (Japan)
2012-07-01T23:59:59.000Z
The evaluation of consequence at the severe accident is the most important as a safety licensing issue for the reactor core of liquid metal cooled fast breeder reactor (LMFBR), since the LMFBR core is not in an optimum condition from the viewpoint of reactivity. This characteristics might induce a super-prompt criticality due to the core geometry change during the core disruptive accident (CDA). The previous CDA analysis codes have been modeled in plural phases dependent on the mechanism driving a super-prompt criticality. Then, the following event is calculated by connecting different codes. This scheme, however, should introduce uncertainty and/or arbitrary to calculation results. To resolve the issues and obtain the consistent calculation results without arbitrary, JNES is developing the ASTERIA-FBR code for the purpose of providing the cross-check analysis code, which is another required scheme to confirm the validity of the evaluation results prepared by applicants, in the safety licensing procedure of the planned high performance core of Monju. ASTERIA-FBR consists of the three major calculation modules, CONCORD, dynamic-GMVP, and FEMAXI-FBR. CONCORD is a three-dimensional thermal-hydraulics calculation module with multi-phase, multi-component, and multi-velocity field model. Dynamic-GMVP is a space-time neutronics calculation module. FEMAXI-FBR calculates the fuel pellet deformation behavior and fuel pin failure behavior. This paper describes the needs of ASTERIA-FBR development, major module outlines, and the model validation status. (authors)
Granular Dynamics in Pebble Bed Reactor Cores
Laufer, Michael Robert
2013-01-01T23:59:59.000Z
a simulant fluid to match the dynamics of fuel pebbles andfuel pebbles through reactor cores with and without coupled fluid
FISSION REACTORS KEYWORDS: core-barrel vibra-
DemaziÃ¨re, Christophe
FISSION REACTORS KEYWORDS: core-barrel vibra- tions, in-core neutron noise, shell- mode vibrations CALCULATION OF THE NEUTRON NOISE INDUCED BY SHELL-MODE CORE-BARREL VIBRATIONS IN A 1-D, TWO-GROUP, TWO-REGION SLAB REACTOR MODEL CARL SUNDE,* CHRISTOPHE DEMAZIÃ?RE, and IMRE PÃZSIT Chalmers University of Technology
UW-Milwaukee Strategic Planning Core Team
Saldin, Dilano
UW-Milwaukee Strategic Planning Core Team MINUTES November 19, 2012 Regents Room, Chapman Hall, 10 Strategic Planning Core team with oversight, coordination, and providing campus leadership with strategic strategic planning framework. c. Distinguished Core Team from Operational teams (Functional and Thematic). 4
W. X. Xue; J. M. Yao; K. Hagino; Z. P. Li; H. Mei; Y. Tanimura
2015-02-18T23:59:59.000Z
The impurity effect of hyperon on atomic nuclei has received a renewed interest in nuclear physics since the first experimental observation of appreciable reduction of $E2$ transition strength in low-lying states of hypernucleus $^{7}_\\Lambda$Li. Many more data on low-lying states of $\\Lambda$ hypernuclei will be measured soon for $sd$-shell nuclei, providing good opportunities to study the $\\Lambda$ impurity effect on nuclear low-energy excitations. We carry out a quantitative analysis of $\\Lambda$ hyperon impurity effect on the low-lying states of $sd$-shell nuclei at the beyond-mean-field level based on a relativistic point-coupling energy density functional (EDF), considering that the $\\Lambda$ hyperon is injected into the lowest positive-parity ($\\Lambda_s$) and negative-parity ($\\Lambda_p$) states. We adopt a triaxially deformed relativistic mean-field (RMF) approach for hypernuclei and calculate the $\\Lambda$ binding energies of hypernuclei as well as the potential energy surfaces (PESs) in $(\\beta, \\gamma)$ deformation plane. We also calculate the PESs for the $\\Lambda$ hypernuclei with good quantum numbers using a microscopic particle rotor model (PRM) with the same relativistic EDF. The triaxially deformed RMF approach is further applied in order to determine the parameters of a five-dimensional collective Hamiltonian (5DCH) for the collective excitations of triaxially deformed core nuclei. Taking $^{25,27}_{\\Lambda}$Mg and $^{31}_{\\Lambda}$Si as examples, we analyse the impurity effects of $\\Lambda_s$ and $\\Lambda_p$ on the low-lying states of the core nuclei...
Superplastic deformation in two microduplex stainless steels
Lesuer, D.R.; Nieh, T.G.; Syn, C.K. [Lawrence Livermore National Lab., CA (United States); Taleff, E.M. [Texas Univ., Austin, TX (United States)
1996-09-01T23:59:59.000Z
The deformation behavior and mechanisms of superplastic flow in two microduplex stainless steels (SuperDux64 and Nitronic 19D) were studied at {similar_to}0.7T{sub m}. The two steels differed in initial grain size by a factor of 3. Both steels exhibited solute-drag-controlled grain boundary sliding in a high temperature {gamma}+{delta} phase field. In a lower temperature {gamma}+{sigma} phase field, the fine-grained steel ({bar L}=5{mu}m) exhibited climb-controlled grain boundary sliding and the coarser- grained steel ({bar L}=15{mu}m) exhibited solute-drag-controlled slip creep.
Kinetic bounding volume hierarchies for deformable objects
Gabriel Zachmann; Tu Clausthal
2006-01-01T23:59:59.000Z
We present novel algorithms for updating bounding volume hierarchies of objects undergoing arbitrary deformations. Therefore, we introduce two new data structures, the kinetic AABB tree and the kinetic BoxTree. The event-based approach of the kinetic data structures framework enables us to show that our algorithms are optimal in the number of updates. Moreover, we show a lower bound for the total number of BV updates, which is independent of the number of frames. We used our kinetic bounding volume hierarchies for collision detection and performed a comparison with the classical bottomup update method. The results show that our algorithms perform up to ten times faster in practically relevant scenarios.
EXAMINATION OF POSTIRRADIATION DEFORMATION MICROSTRUCTURES IN F82H
Gelles, David S.; Schaublin, R.
2002-09-01T23:59:59.000Z
The deformed microstructures of irradiated F82H uniaxial tensile specimens have been examined following irradiation in HFR to 2.6 dpa at 32 C in order to identify controlling mechanisms. Deformation following irradiation is found to occur in poorly defined channels, causing formation of discrete steps at surfaces, similar to that in unirradiated steel. Deformation is by motion of individual a/2<111> dislocations.
Structure and deformation mechanisms along the Tonale Line, n. Italy
Welker, Mary Clare
1985-01-01T23:59:59.000Z
of Advisory Committee: John M. Logan Field observations and sampling are combined with petrofabric and fracture analyses to characterize the structure and deformation mechanisms related to a segment of the Tonale Line fault zone in northern Italy. Mylonite... microstructures and fabrics are developed superimposed by cataclasites and fault gouge; the latter being character istic of deformation at shallow depths. The ductile deformation associated with faulting along the Tonale Line occurred under greenschist...
Deformed relativistic and nonrelativistic symmetries on canonical noncommutative spaces
Banerjee, Rabin; Kumar, Kuldeep [S.N. Bose National Centre for Basic Sciences, JD Block, Sector 3, Salt Lake, Kolkata 700098 (India); Department of Physics, Panjab University, Chandigarh 160014 (India)
2007-02-15T23:59:59.000Z
We study the general deformed conformal-Poincare (Galilean) symmetries consistent with relativistic (nonrelativistic) canonical noncommutative spaces. In either case we obtain deformed generators, containing arbitrary free parameters, which close to yield new algebraic structures. We show that a particular choice of these parameters reproduces the undeformed algebra. The modified coproduct rules and the associated Hopf algebra are also obtained. Finally, we show that for the choice of parameters leading to the undeformed algebra, the deformations are represented by twist functions.
Generator stator core vent duct spacer posts
Griffith, John Wesley (Schenectady, NY); Tong, Wei (Clifton Park, NY)
2003-06-24T23:59:59.000Z
Generator stator cores are constructed by stacking many layers of magnetic laminations. Ventilation ducts may be inserted between these layers by inserting spacers into the core stack. The ventilation ducts allow for the passage of cooling gas through the core during operation. The spacers or spacer posts are positioned between groups of the magnetic laminations to define the ventilation ducts. The spacer posts are secured with longitudinal axes thereof substantially parallel to the core axis. With this structure, core tightness can be assured while maximizing ventilation duct cross section for gas flow and minimizing magnetic loss in the spacers.
ankle deformity secondary: Topics by E-print Network
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in the Trapezium Cluster: First Scientific Results from the MMT Deformable Secondary Mirror Adaptive Optics System Astrophysics (arXiv) Summary: We present the first scientific...
Free motion in deformed (quantum) four-dimensional space
A. N. Leznov
2007-07-23T23:59:59.000Z
It is shown that trajectories of free motion of the particles in deformed ("quantum") four dimensional space-time are quadratic curves.
Contemporary Tectonic Deformation of the Basin and Range Province...
Belt lithosphere is rheologically weak. However, we show that linear gradients in viscosity and gravitational potential energy can also effectively concentrate deformation. In...
Deformation and seismicity in the Coso geothermal area, Inyo...
interferometry Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Deformation and seismicity in the Coso geothermal area, Inyo County,...
FINAL REPORT Grothendieck-Teichmller Groups, Deformation and
FINAL REPORT Grothendieck-Teichmüller Groups, Deformation and Operads [GDO programme] January (Nice) and Nick Woodhouse (CMI). Programme Partner: Clay Mathematics Institute. State of the art
Inflation and deformation of conformal field theory
Garriga, Jaume; Urakawa, Yuko, E-mail: jaume.garriga@ub.edu, E-mail: yurakawa@ffn.ub.es [Departament de Física Fonamental i Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain)
2013-07-01T23:59:59.000Z
It has recently been suggested that a strongly coupled phase of inflation may be described holographically in terms of a weakly coupled quantum field theory (QFT). Here, we explore the possibility that the wave function of an inflationary universe may be given by the partition function of a boundary QFT. We consider the case when the field theory is a small deformation of a conformal field theory (CFT), by the addition of a relevant operator O, and calculate the primordial spectrum predicted in the corresponding holographic inflation scenario. Using the Ward-Takahashi identity associated with Weyl rescalings, we derive a simple relation between correlators of the curvature perturbation ? and correlators of the deformation operator O at the boundary. This is done without specifying the bulk theory of gravitation, so that the result would also apply to cases where the bulk dynamics is strongly coupled. We comment on the validity of the Suyama-Yamaguchi inequality, relating the bi-spectrum and tri-spectrum of the curvature perturbation.
Core Competencies | Department of Energy
Office of Environmental Management (EM)
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Evgeny A. Ryzhov; K. V. Koshel
2012-09-27T23:59:59.000Z
In the frame of a three-layer quasi-geostrophic analytical model of a $f$-plane geophysical flow, Lagrangian advection being induced by the interaction of a monopole vortex with an isolated topographic feature is addressed. Two different cases when the monopole locates either within the upper or the middle layer are of our interest. In the bottom layer, there is a delta function topographic feature, which generates a closed recirculation region in its vicinity due to the background flow. This recirculation region extends to the middle and upper layers, and it plays the role of a topographic vortex. The interaction between the monopole and the topographic vortex causes complex, including chaotic, advection of fluid particles. We show that the model's parameters, namely, the monopole and topographic vortices' strengths and initial positions, the layers' depths and densities are responsible for the diverse advection patterns. While the patterns are rather complicated, however, one can single out two major processes, which mostly govern fluid particle advection. The first one is the variation in time of the system's phase space structure, so that within the closed region of the topographic vortex, there appear periodically unclosed particle pathways by which the particles leave the topographic vortex. The second one is chaotic advection that arises from the nonstationarity of the monopole-topography interaction.
Effects of trailing edge flap dynamic deployment on blade-vortex interactions
Nelson, Carter T.
1997-01-01T23:59:59.000Z
code based on potential flow theory with provisions for deformable geometry to incorporate a trailing edge flap. Experimental tests were conducted using a 2-D wind tunnel setup incorporating a pressure instrumented airfoil section with a deployable 20...
Lewis, M.; Grimshaw, A. [Univ. of Virginia, Charlottesville, VA (United States)
1996-12-31T23:59:59.000Z
The Legion project at the University of Virginia is an architecture for designing and building system services that provide the illusion of a single virtual machine to users, a virtual machine that provides secure shared object and shared name spaces, application adjustable fault-tolerance, improved response time, and greater throughput. Legion targets wide area assemblies of workstations, supercomputers, and parallel supercomputers, Legion tackles problems not solved by existing workstation based parallel processing tools; the system will enable fault-tolerance, wide area parallel processing, inter-operability, heterogeneity, a single global name space, protection, security, efficient scheduling, and comprehensive resource management. This paper describes the core Legion object model, which specifies the composition and functionality of Legion`s core objects-those objects that cooperate to create, locate, manage, and remove objects in the Legion system. The object model facilitates a flexible extensible implementation, provides a single global name space, grants site autonomy to participating organizations, and scales to millions of sites and trillions of objects.
Otani, Yoshichika
Controlled propagation of locally excited vortex dynamics in linear nanomagnet arrays This article. Here, we present a controlled propagation of locally excited magnetic vortex dynamics through a linear. Phys. D: Appl. Phys. 43 (2010) 335001 (7pp) doi:10.1088/0022-3727/43/33/335001 Controlled propagation
Protas, Bartosz
. Following a comprehensive review of earlier approaches, we discuss how methods of modern control and optimization theory can be employed to solve control problems for vortex system. In addition, we also address vortex systems, in the second part of the paper we also introduce a novel approach to the control
Chen, Kai; Advanced Light Source; UCLA
2008-01-01T23:59:59.000Z
Plastic deformation in Al (Cu) interconnects stressed bygrain orientation [7], study plastic deformation [12-15] andThis aspect of EM-induced plastic deformation in grains
Mesh Puppetry: Cascading Optimization of Mesh Deformation with Inverse Kinematics
Zhou, Kun
approach builds upon traditional rigging by optimizing skeleton position and vertex weights. Keywords: Mesh deformation, nonlinear optimization, inverse kinematics, geometry processing. 1 Introduction,mathieu}@caltech.edu Figure 1: Armadillo Olympics: The Armadillo model (top left) can be deformed to take various sport poses
Virtual Clay: Haptics-based Deformable Solids of Arbitrary Topology
McDonnell, Kevin
Virtual Clay: Haptics-based Deformable Solids of Arbitrary Topology Kevin T. McDonnell and Hong Qin|qin}@cs.sunysb.edu Abstract. This paper presents Virtual Clay as a novel, interactive, dy- namic, haptics-based deformable solid of arbitrary topology. Our Virtual Clay methodology is a unique, powerful visual modeling paradigm
Cortical Hemisphere Registration Via Large Deformation Diffeomorphic Metric Curve
Qiu, Anqi
on the relation between individual brains and the atlas. This is a powerful approach allowing us to study a largeCortical Hemisphere Registration Via Large Deformation Diffeomorphic Metric Curve Mapping Anqi Qiu1 Science, Johns Hopkins University Abstract. We present large deformation diffeomorphic metric curve
Large Deformation Unbiased Diffeomorphic Nonlinear Image Registration: Theory and Implementation
Soatto, Stefano
Large Deformation Unbiased Diffeomorphic Nonlinear Image Registration: Theory and Implementation for con- structing large deformation log-unbiased image registra- tion models that generate theoretically the statistical distributions of Jacobian maps in the logarithmic space. To demonstrate the power of the proposed
Micrographic detection of plastic deformation in nickel base alloys
Steeves, Arthur F. (Schenectady, NY); Bibb, Albert E. (Clifton Park, NY)
1984-01-01T23:59:59.000Z
A method for detecting low levels of plastic deformation in metal articles comprising electrolytically etching a flow free surface of the metal article with nital at a current density of less than about 0.1 amp/cm.sup.2 and microscopically examining the etched surface to determine the presence of alternating striations. The presence of striations indicates plastic deformation in the article.
Seismology of plastic deformation Jero^me Weiss *, Francois Louchet
Weiss, Jérôme
Seismology of plastic deformation Je´ro^me Weiss *, Franc¸ois Louchet Laboratoire de Glaciologie et-free critical picture of dislocational plasticity that challenges the classical continuum models of plasticity rights reserved. Keywords: Acoustic methods; Dislocation dynamics; Plastic deformation; Self
Granite ascent and emplacement during contractional deformation in convergent orogens
Solar, Gary S.
Granite ascent and emplacement during contractional deformation in convergent orogens MICHAEL BROWN of granite melt through the crust in convergent orogens. During contractional deformation, Â¯ow of melt to weakly discordant irregular granite sheets occur in zones of higher strain, which suggests percolative
On the thermomechanical deformation of silver shape memory nanowires
Lin, Xi
On the thermomechanical deformation of silver shape memory nanowires Harold S. Park *, Changjiang an analysis of the uniaxial thermomechanical deformation of single-crystal silver shape memory nanowires using atomistic simulations. We first demonstrate that silver nanowires can show both shape memory
DNA Deformation Energy as an Indirect Recognition Mechanism in
Lathrop, Richard H.
DNA Deformation Energy as an Indirect Recognition Mechanism in Protein-DNA Interactions Kimberly A. Senear Abstract--Proteins that bind to specific locations in genomic DNA control many basic cellular. Deformation energy, which models the energy required to bend DNA from its native shape to its shape when bound
Medially Based Meshing with Finite Element Analysis of Prostate Deformation
Crouch, Jessica R.
Medially Based Meshing with Finite Element Analysis of Prostate Deformation Jessica R. Crouch1 have approached prostate imaging problems using meth- ods that incorporate finite element analysis. Assume the prostate is a linearly elastic body and compute its deformation using finite element analysis
Deformations of Quantum Symmetric Algebras Extended by Groups
Shakalli Tang, Jeanette
2012-07-16T23:59:59.000Z
The study of deformations of an algebra has been a topic of interest for quite some time, since it allows us to not only produce new algebras but also better understand the original algebra. Given an algebra, finding all its deformations is...
Tetrahedral Mesh Generation for Deformable Bodies Neil Molino
Stanford University
, the finite element method or an optimization approach to relax the positions of both the interior refinement, finite element method, level set methods 1 Introduction Tetrahedral meshes are used in a number for fluid flow and heat transfer where the mesh is not deformed, and for small deformation solids where
High stroke pixel for a deformable mirror
Miles, Robin R.; Papavasiliou, Alexandros P.
2005-09-20T23:59:59.000Z
A mirror pixel that can be fabricated using standard MEMS methods for a deformable mirror. The pixel is electrostatically actuated and is capable of the high deflections needed for spaced-based mirror applications. In one embodiment, the mirror comprises three layers, a top or mirror layer, a middle layer which consists of flexures, and a comb drive layer, with the flexures of the middle layer attached to the mirror layer and to the comb drive layer. The comb drives are attached to a frame via spring flexures. A number of these mirror pixels can be used to construct a large mirror assembly. The actuator for the mirror pixel may be configured as a crenellated beam with one end fixedly secured, or configured as a scissor jack. The mirror pixels may be used in various applications requiring high stroke adaptive optics.
Reversibility of Red blood Cell deformation
Maria Zeitz; Pierre Sens
2011-11-22T23:59:59.000Z
The ability of cells to undergo reversible shape changes is often crucial to their survival. For Red Blood Cells (RBCs), irreversible alteration of the cell shape and flexibility often causes anemia. Here we show theoretically that RBCs may react irreversibly to mechanical perturbations because of tensile stress in their cytoskeleton. The transient polymerization of protein fibers inside the cell seen in sickle cell anemia or a transient external force can trigger the formation of a cytoskeleton-free membrane protrusion of micrometer dimensions. The complex relaxation kinetics of the cell shape is shown to be responsible for selecting the final state once the perturbation is removed, thereby controlling the reversibility of the deformation. In some case, tubular protrusion are expected to relax via a peculiar "pearling instability".
Ultrasound scattering and the study of vortex correlations in disordered flows
Denis Boyer; Fernando Lund
1999-12-14T23:59:59.000Z
In an idealized way, some turbulent flows can be pictured by assemblies of many vortices characterized by a set of particle distribution functions. Ultrasound provide an useful, nonintrusive, tool to study the spatial structure of vorticity in flows. This is analogous to the use of elastic neutron scattering to determine liquid structure. We express the dispersion relation, as well as the scattering cross section, of sound waves propagating in a ``liquid'' of identical vortices as a function of vortex pair correlation functions. In two dimensions, formal analogies with ionic liquids are pointed out.
Geometry and scaling of tangled vortex lines in three-dimensional random wave fields
Alexander J. Taylor; Mark R. Dennis
2015-01-20T23:59:59.000Z
The short- and long-scale behaviour of tangled wave vortices (nodal lines) in random three-dimensional wave fields is studied via computer experiment. The zero lines are tracked in numerical simulations of periodic superpositions of three-dimensional complex plane waves. The probability distribution of local geometric quantities such as curvature and torsion are compared to previous analytical and new Monte Carlo results from the isotropic Gaussian random wave model. We further examine the scaling and self-similarity of tangled wave vortex lines individually and in the bulk, drawing comparisons with other physical systems of tangled filaments.
Extraordinary optical transmission and vortex excitation by periodic arrays of Fresnel zone plates
Roszkiewicz, A
2013-01-01T23:59:59.000Z
Extraordinary optical transmission and good focusing properties of a two-dimensional scattering structure is presented. The structure is made of Fresnel zone plates periodically arranged along two orthogonal directions. Each plate consists of two ring-shaped waveguides supporting modes that match the symmetry of a circularly polarized incident plane wave. High field concentration at the focal plane is obtained with short transverse and long longitudinal foci diameters. Optical vortex excitation in a paraxial region of the transmitted field is also observed and analysed in terms of cross-polarisation coupling. The structure presented may appear useful in visualization, trapping and precise manipulations of nanoparticles.
Critical current density and mechanism of vortex pinning in KxFe2-ySe? doped with S
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Lei, Hechang; Petrovic, C.
2011-08-01T23:59:59.000Z
We report the critical current density Jc in KxFe2-ySe2-zSz crystals. The Jc can be enhanced significantly with optimal S doping (z=0.99). For K0.70(7)Fe1.55(7)Se1.01(2)S0.99(2), the weak fishtail effect is found for H II c. The normalized vortex pinning forces follow the scaling law with a maximum position at 0.41 of the reduced magnetic field. These results demonstrate that the small size normal point defects dominate the vortex pinning mechanism.
Coupled Full-Core Problem witssh VERA
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Inc Rensselaer Polytechnic Institute Core Physics, Inc. Southern States Energy Board City University of New York Texas A&M University Florida State University University of...
Sandia National Laboratories: QD core shell heterostructures
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
QD core shell heterostructures Introduction of Prof. David Kelley and UC Merced to SSLS On January 11, 2012, in Energy Efficiency, News, News & Events, Partnership, Solid-State...
Material with core-shell structure
Luhrs, Claudia (Rio Rancho, NM); Richard, Monique N. (Ann Arbor, MI); Dehne, Aaron (Maumee, OH); Phillips, Jonathan (Rio Rancho, NM); Stamm, Kimber L. (Ann Arbor, MI); Fanson, Paul T. (Brighton, MI)
2011-11-15T23:59:59.000Z
Disclosed is a material having a composite particle, the composite particle including an outer shell and a core. The core is made from a lithium alloying material and the outer shell has an inner volume that is greater in size than the core of the lithium alloying material. In some instances, the outer mean diameter of the outer shell is less than 500 nanometers and the core occupies between 5 and 99% of the inner volume. In addition, the outer shell can have an average wall thickness of less than 100 nanometers.
Surface tension of the core-crust interface of neutron stars with global charge neutrality
Jorge A. Rueda; Remo Ruffini; Yuan-Bin Wu; She-Sheng Xue
2014-03-19T23:59:59.000Z
It has been shown recently that taking into account strong, weak, electromagnetic, and gravitational interactions, and fulfilling the global charge neutrality of the system, a transition layer will happen between the core and crust of neutron stars, at the nuclear saturation density. We use relativistic mean field theory together with the Thomas-Fermi approximation to study the detailed structure of this transition layer and calculate its surface and Coulomb energy. We find that the surface tension is proportional to a power-law function of the baryon number density in the core bulk region. We also analyze the influence of the electron component and the gravitational field on the structure of the transition layer and the value of the surface tension to compare and contrast with known phenomenological results in nuclear physics. Based on the above results we study the instability against Bohr-Wheeler surface deformations in the case of neutron stars obeying global charge neutrality. Assuming the core-crust transition at nuclear density $\\rho_{core}\\approx 2.7 * 10^{14}$ g cm$^{-3}$, we find that the instability sets the upper limit to the crust density, $\\rho_{crust}^{crit}\\approx 1.2 * 10^{14}$ g cm$^{-3}$. This result implies a nonzero lower limit to the maximum electric field of the core-crust transition surface and makes inaccessible a limit of quasilocal charge neutrality in the limit $\\rho_{crust}=\\rho_{core}$. The general framework presented here can be also applied to study the stability of sharp phase transitions in hybrid stars as well as in strange stars, both bare and with outer crust. The results of this work open the way to a more general analysis of the stability of these transition surfaces, accounting for other effects such as gravitational binding, centrifugal repulsion, magnetic field induced by rotating electric field, and therefore magnetic dipole-dipole interactions.
Westinghouse Fuel Assemblies Performance after Operation in South-Ukraine NPP Mixed Core
Abdullayev, A. M.; Kulish, G. V.; Slyeptsov, O.; Slyeptsov, S.; Aleshin, Y.; Sparrow, S.; Lashevych, P.; Sokolov, D.; Latorre, Richard
2013-09-14T23:59:59.000Z
The evaluation of WWER-1000 Westinghouse fuel performance was done using the results of post–irradiation examinations of six LTAs and the WFA reload batches that have operated normally in mixed cores at South-Ukraine NPP, Unit-3 and Unit-2. The data on WFA/LTA elongation, FR growth and bow, WFA bow and twist, RCCA drag force and drag work, RCCA drop time, FR cladding integrity as well as the visual observation of fuel assemblies obtained during the 2006-2012 outages was utilized. The analysis of the measured data showed that assembly growth, FR bow, irradiation growth, and Zr-1%Nb grid and ZIRLO cladding corrosion lies within the design limits. The RCCA drop time measured for the LTA/WFA is about 1.9 s at BOC and practically does not change at EOC. The measured WFA bow and twist, and data of drag work on RCCA insertion showed that the WFA deformation in the mixed core is mostly controlled by the distortion of Russian FAs (TVSA) having the higher lateral stiffness. The visual inspection of WFAs carried out during the 2012 outages revealed some damage to the Zr-1%Nb grid outer strap for some WFAs during the loading sequence. The performed fundamental investigations allowed identifying the root cause of grid outer strap deformation and proposing the WFA design modifications for preventing damage to SG at a 225 kg handling trip limit.
EFFECT OF GRAIN SIZE ON THE ACOUSTIC EMISSION GENERATED DURING PLASTIC DEFORMATION OF ALUMINUM
Baram, J.
2013-01-01T23:59:59.000Z
PLASTIC DEFORMATION OF ALUMINUM LAWRENCE BERKELEY LABORATORYDURING PLASTIC DEFORMATION OF ALUMINUM J. Baram Materialsof polycrystalline aluminum, of different grain sizes and at
MAP, MAC, and Vortex-rings Configurations in the Weinberg-Salam Model
Rosy Teh; Ban-Loong Ng; Khai-Ming Wong
2015-03-20T23:59:59.000Z
We report on the presence of new axially symmetric monopoles, antimonopoles and vortex-rings solutions of the SU(2)$\\times$U(1) Weinberg-Salam model of electromagnetic and weak interactions. When the $\\phi$-winding number $n=1$, and 2, the configurations are monopole-antimonopole pair (MAP) and monopole-antimonopole chain (MAC) with poles of alternating sign magnetic charge arranged along the $z$-axis. Vortex-rings start to appear from the MAP and MAC configurations when the winding number $n=3$. The MAP configurations possess zero net magnetic charge whereas the MAC configurations possess net magnetic charge of $4\\pi n/e$. In the MAP configurations, the monopole-antimonopole pair is bounded by the ${\\cal Z}^0$ field flux string and there is an electromagnetic current loop encircling it. The monopole and antimonopole possess magnetic charges $\\pm\\frac{4\\pi n}{e}\\sin^2\\theta_W$ respectively. In the MAC configurations there is no string connecting the monopole and the adjacent antimonopole and they possess magnetic charges $\\pm\\frac{4\\pi n}{e}$ respectively. The MAC configurations possess infinite total energy and zero magnetic dipole moment whereas the MAP configurations which are actually sphalerons possess finite total energy and magnetic dipole moment. The configurations were investigated for varying values of Higgs self-coupling constant $0\\leq \\lambda\\leq 40$ at Weinberg angle $\\theta_W=\\frac{\\pi}{4}$.
Filamentary structures in dense plasma focus: Current filaments or vortex filaments?
Soto, Leopoldo, E-mail: lsoto@cchen.cl; Pavez, Cristian; Moreno, José [Comisión Chilena de Energía Nuclear, CCHEN, Casilla 188-D, Santiago (Chile); Center for Research and Applications in Plasma Physics and Pulsed Power, P4, Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andrés Bello, República 220, Santiago (Chile); Castillo, Fermin [Universidad Nacional Autónoma de México, Cuernavaca, México (Mexico); Veloso, Felipe [Instituto de Física, Pontificia Universidad Católica de Chile, 7820436 Santiago (Chile); Auluck, S. K. H. [Bhabha Atomic Research Center, Mumbai 400 085 (India)
2014-07-15T23:59:59.000Z
Recent observations of an azimuthally distributed array of sub-millimeter size sources of fusion protons and correlation between extreme ultraviolet (XUV) images of filaments with neutron yield in PF-1000 plasma focus have re-kindled interest in their significance. These filaments have been described variously in literature as current filaments and vortex filaments, with very little experimental evidence in support of either nomenclature. This paper provides, for the first time, experimental observations of filaments on a table-top plasma focus device using three techniques: framing photography of visible self-luminosity from the plasma, schlieren photography, and interferometry. Quantitative evaluation of density profile of filaments from interferometry reveals that their radius closely agrees with the collision-less ion skin depth. This is a signature of relaxed state of a Hall fluid, which has significant mass flow with equipartition between kinetic and magnetic energy, supporting the “vortex filament” description. This interpretation is consistent with empirical evidence of an efficient energy concentration mechanism inferred from nuclear reaction yields.
Direct femtosecond laser ablation of copper with an optical vortex beam
Anoop, K. K.; Rubano, A.; Marrucci, L.; Bruzzese, R.; Amoruso, S., E-mail: amoruso@na.infn.it [Dipartimento di Fisica, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); CNR-SPIN, UOS Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Fittipaldi, R.; Vecchione, A. [CNR-SPIN, UOS Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (Italy); Wang, X.; Paparo, D. [CNR-SPIN, UOS Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy)
2014-09-21T23:59:59.000Z
Laser surface structuring of copper is induced by laser ablation with a femtosecond optical vortex beam generated via spin-to-orbital conversion of the angular momentum of light by using a q-plate. The variation of the produced surface structures is studied as a function of the number of pulses, N, and laser fluence, F. After the first laser pulse (N?=?1), the irradiated surface presents an annular region characterized by a corrugated morphology made by a rather complex network of nanometer-scale ridges, wrinkles, pores, and cavities. Increasing the number of pulses (2??1000) and a deep crater is formed. The nanostructure variation with the laser fluence, F, also evidences an interesting dependence, with a coarsening of the structure morphology as F increases. Our experimental findings demonstrate that direct femtosecond laser ablation with optical vortex beams produces interesting patterns not achievable by the more standard beams with a Gaussian intensity profile. They also suggest that appropriate tuning of the experimental conditions (F, N) can allow generating micro- and/or nano-structured surface for any specific application.
Vortex and structural dynamics of a flexible cylinder in cross-flow
Shang, Jessica K., E-mail: jshang@princeton.edu; Stone, Howard A. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Smits, Alexander J. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Monash University, VIC 3800 (Australia)
2014-05-15T23:59:59.000Z
A low-density, flexible cantilevered cylinder was permitted to vibrate freely under the influence of vortex shedding in the laminar flow regime. We find that the vortex-induced vibrations (VIV) of a flexible cantilever depart from those of a flexible cylinder that is fixed at both ends. In particular, we find discontinuous regions of VIV behavior – here called states – as a function of the reduced velocity U{sup *}. These states are demarcated by discrete changes in the dominant eigenmodes of the structural response as the cylinder vibrates in progressively higher structural modes with increasing U{sup *}. The contribution of structural modes can be identified readily by a modal projection of the cylinder oscillation onto known cantilever beam modes. Oscillation frequencies do not monotonically increase with U{sup *}. The wake response between different states is also found to have distinct characteristics; of particular note is the occurrence of a P+S wake over one of these regions, which is associated with a high-amplitude vibration of the cylinder that is due to the constructive interference of contributing eigenmodes.
Core-Level Activity Prediction for Multi-Core Power Management
John, Lizy Kurian
1 Core-Level Activity Prediction for Multi-Core Power Management W. Lloyd Bircher1 and Lizy, University of Texas at Austin Abstract - Existing power management techniques operate by reducing performance generated by the workloads on individual cores. This causes sub-optimal power management and over
Core Science Requirement Final Document Page 1 THE CORE SCIENCE REQUIREMENT and
Lagalante, Anthony F.
Core Science Requirement Final Document Page 1 THE CORE SCIENCE REQUIREMENT and MENDEL SCIENCE EXPERIENCE COURSES Core requirement of 2 semesters of science with laboratory; requirement to be met by the end of the sophomore year Rationale Science literacy is an integral part of the intellectual
Kato, Chinami; Yamada, Shoichi; Takahashi, Koh; Umeda, Hideyuki; Yoshida, Takashi; Ishidoshiro, Koji
2015-01-01T23:59:59.000Z
Aiming to distinguish two types of progenitors of core collapse supernovae, i.e., one with a core composed mainly of oxygen and neon (abbreviated as ONe core) and the other with an iron core (or Fe core), we calculated the luminosities and spectra of neutrinos emitted from these cores prior to gravitational collapse, taking neutrino oscillation into account. We found that the total energies emitted as $\\bar{\
The Formation and Evolution of Prestellar Cores
Philippe André; Shantanu Basu; Shu-ichiro Inutsuka
2008-01-28T23:59:59.000Z
Improving our understanding of the initial conditions and earliest stages of star formation is crucial to gain insight into the origin of stellar masses, multiple systems, and protoplanetary disks. We review the properties of low-mass dense cores as derived from recent millimeter/submillimeter observations of nearby molecular clouds and discuss them in the context of various contemporary scenarios for cloud core formation and evolution. None of the extreme scenarios can explain all observations. Pure laminar ambipolar diffusion has relatively long growth times for typical ionization levels and has difficulty satisfying core lifetime constraints. Purely hydrodynamic pictures have trouble accounting for the inefficiency of core formation and the detailed velocity structure of individual cores. A possible favorable scenario is a mixed model involving gravitational fragmentation of turbulent molecular clouds close to magnetic criticality. The evolution of the magnetic field and angular momentum in individual cloud cores after the onset of gravitational collapse is also discussed. In particular, we stress the importance of radiation-magnetohydrodynamical processes and resistive MHD effects during the protostellar phase. We also emphasize the role of the formation of the short-lived first (protostellar) core in providing a chance for sub-fragmentation into binary systems and triggering MHD outflows. Future submillimeter facilities such as Herschel and ALMA will soon provide major new observational constraints in this field. On the theoretical side, an important challenge for the future will be to link the formation of molecular clouds and prestellar cores in a coherent picture.
UW-Milwaukee Strategic Planning Core Team
Saldin, Dilano
UW-Milwaukee Strategic Planning Core Team Minutes Tuesday, December 18, 2012 Regents Room, Chapman Hall, 8-10 a.m. 1. Welcome and meeting objectives 2. Core Team Suggested Guidelines ("Ground Rules") a. Communication (within team and with across campus and others) Input is always welcomed Open communication
UNL Core for Applied Genomics and Ecology
Farritor, Shane
UNL Core for Applied Genomics and Ecology Bioinformatics training Roche 454 GS-FLX Registration, Microbiomes, Variant Analysis, Whole Genomes, Transcriptomes Data Analysis and Statistics CAGE database and employer. University of Nebraska-Lincoln*Core for Applied Genomics and Ecology* 323 Filley Hall *Lincoln
Idealized Test Cases for Dynamical Core Experiments
Jablonowski, Christiane
Idealized Test Cases for Dynamical Core Experiments Christiane Jablonowski (University of Michigan-13/2006 #12;Motivation · Test cases for 3D dynamical cores on the sphere are hard to find in the literature groups lack standardized & easy-to-use analysis techniques · Idea: Establish a collection of test cases
Lateral restraint assembly for reactor core
Gorholt, Wilhelm (San Diego, CA); Luci, Raymond K. (Del Mar, CA)
1986-01-01T23:59:59.000Z
A restraint assembly for use in restraining lateral movement of a reactor core relative to a reactor vessel wherein a plurality of restraint assemblies are interposed between the reactor core and the reactor vessel in circumferentially spaced relation about the core. Each lateral restraint assembly includes a face plate urged against the outer periphery of the core by a plurality of compression springs which enable radial preloading of outer reflector blocks about the core and resist low-level lateral motion of the core. A fixed radial key member cooperates with each face plate in a manner enabling vertical movement of the face plate relative to the key member but restraining movement of the face plate transverse to the key member in a plane transverse to the center axis of the core. In this manner, the key members which have their axes transverse to or subtending acute angles with the direction of a high energy force tending to move the core laterally relative to the reactor vessel restrain such lateral movement.
Moving core beam energy absorber and converter
Degtiarenko, Pavel V.
2012-12-18T23:59:59.000Z
A method and apparatus for the prevention of overheating of laser or particle beam impact zones through the use of a moving-in-the-coolant-flow arrangement for the energy absorbing core of the device. Moving of the core spreads the energy deposition in it in 1, 2, or 3 dimensions, thus increasing the effective cooling area of the device.
Experto Universitario Java Sesin 1: Spring core
Escolano, Francisco
Enterprise Spring © 2012-2013 Depto. Ciencia de la Computación e IA Spring core Puntos a tratar 2 #12;Experto Universitario Java Enterprise Spring © 2012-2013 Depto. Ciencia de la Computación e IA;Experto Universitario Java Enterprise Spring © 2012-2013 Depto. Ciencia de la Computación e IA Spring core
Method and apparatus for recovering unstable cores
McGuire, Patrick L. (Los Alamos, NM); Barraclough, Bruce L. (Los Alamos, NM)
1983-01-01T23:59:59.000Z
A method and apparatus suitable for stabilizing hydrocarbon cores are given. Such stabilized cores have not previously been obtainable for laboratory study, and such study is believed to be required before the hydrate reserves can become a utilizable resource. The apparatus can be built using commercially available parts and is very simple and safe to operate.
Module Handbook Core Univ. of Oldenburg
Habel, Annegret
Energy Conversion Process Â· Location Dependence of Wind Energy Potential and Wind Energy Forecasting/EUREC Course 2008/2009 #12;EUREC Core Courses at University of Oldenburg, 1st Semester Wind Energy Module Module Description: Wind Energy Field: Core Oldenburg Courses: Wind Energy Wind Energy
New version of $q$-deformed supersymmetric quantum mechanics
Gavrilik, A M; Lukash, A V
2013-01-01T23:59:59.000Z
A new version of the q-deformed supersymmetric quantum mechanics (q-SQM), which is inspired by the Tamm--Dankoff-type (TD-type) deformation of quantum harmonic oscillator, is constructed. The obtained algebra of q-SQM is similar to that in Spiridonov's approach. However, within our version of q-SQM, the ground state found explicitly in the special case of superpotential yiealding q-superoscillator turns out to be non-Gaussian and takes the form of special (TD-type) q-deformed Gaussian.
Relativistic Hartree-Fock-Bogoliubov model for deformed nuclei
Ebran, J.-P.; Khan, E.; Pena Arteaga, D. [Institut de Physique Nucleaire, Universite Paris-Sud, IN2P3-CNRS, FR-91406 Orsay Cedex (France); Vretenar, D. [Physics Department, Faculty of Science, University of Zagreb, HR-10000 Zagreb (Croatia)
2011-06-15T23:59:59.000Z
The relativistic Hartree-Fock-Bogoliubov model for axially deformed nuclei (RHFBz) is introduced. The model is based on an effective Lagrangian with density-dependent meson-nucleon couplings in the particle-hole channel, and the central part of the Gogny force is used in the pairing channel. The RHFBz quasiparticle equations are solved by expansion in the basis of a deformed harmonic oscillator. Illustrative RHFBz calculations are performed for carbon, neon, and magnesium isotopes. The effect of explicitly including the pion field is investigated for binding energies, deformation parameters, and charge radii and has an impact on the nuclei's shape.
Deformation twinning mechanisms in FCC and HCP metals
Wang, Jian [Los Alamos National Laboratory; Tome, Carlos N [Los Alamos National Laboratory; Beyerlein, Irene J [Los Alamos National Laboratory; Misra, Amit [Los Alamos National Laboratory; Mara, N [Los Alamos National Laboratory
2011-01-31T23:59:59.000Z
We report the recent work on twinning and detwinning in fcc and hcp metals based on the in situ and ex situ TEM observations and molecular dynamics simulations. Three aspects are discussed in this paper. (1) Detwinning in single-phase Cu with respect to growth twins, (2) deformation twinning in Ag-Cu composites, and (3) deformation twinning mechanisms in hcp metals. The main conclusion is that atomic structures of interfaces (twin boundaries, two-phases interface, and grain boundaries) play a crucial role in nucleating and propagating of deformation twins.
q-Deformed Boson Oscillators and Zero Point Energy
P. Narayana Swamy
1999-09-22T23:59:59.000Z
Just as for the ordinary quantum harmonic oscillators, we expect the zero-point energy to play a crucial role in the correct high temperature behavior. We accordingly reformulate the theory of the statistical distribution function for the q-deformed boson oscillators and develop an approximate theory incorporating the zero-point energy. We are then able to demonstrate that for small deformations, the theory reproduces the correct limits both for very high temperatures and for very low temperatures. The deformed theory thus reduces to the undeformed theory in these extreme cases.
Emergent noncommutative gravity from a consistent deformation of gauge theory
Cortese, Ignacio; Garcia, J Antonio [Departamento de Fisica de Altas Energias, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico D. F. 04510 (Mexico)
2010-05-15T23:59:59.000Z
Starting from a standard noncommutative gauge theory and using the Seiberg-Witten map, we propose a new version of a noncommutative gravity. We use consistent deformation theory starting from a free gauge action and gauging a killing symmetry of the background metric to construct a deformation of the gauge theory that we can relate with gravity. The result of this consistent deformation of the gauge theory is nonpolynomial in A{sub {mu}.} From here we can construct a version of noncommutative gravity that is simpler than previous attempts. Our proposal is consistent and is not plagued with the problems of other approaches like twist symmetries or gauging other groups.
CFD Solvers on Many-core Processors
Brandvik, Tobias
2008-11-11T23:59:59.000Z
cores with 4 · 106 transistors each gives 10 times the performance as 1 big core 0 0.5 1 1.5 2 2.5 3 3.5 4 x 108Number of transistors P e r f o r m a n c e CFD Solvers on Many-core Processors – p.8/36 Everyone is going parallel Every major chip vendor... on Many-core Processors – p.22/36 Stencil operations Evaluate ?2u?x2 on a regular grid: DO K=2,NK-1 DO J=2,NJ-1 DO I=2,NI-1 D2UDX2(I,J,K) = (U(I+1,J,K) - 2.0*U(I,J,K) + & U(I-1,J,K))/(DX*DX) END DO END DO END DO CFD Solvers on Many-core Processors – p.23...
PRISMATIC CORE COUPLED TRANSIENT BENCHMARK
J. Ortensi; M.A. Pope; G. Strydom; R.S. Sen; M.D. DeHart; H.D. Gougar; C. Ellis; A. Baxter; V. Seker; T.J. Downar; K. Vierow; K. Ivanov
2011-06-01T23:59:59.000Z
The Prismatic Modular Reactor (PMR) is one of the High Temperature Reactor (HTR) design concepts that have existed for some time. Several prismatic units have operated in the world (DRAGON, Fort St. Vrain, Peach Bottom) and one unit is still in operation (HTTR). The deterministic neutronics and thermal-fluids transient analysis tools and methods currently available for the design and analysis of PMRs have lagged behind the state of the art compared to LWR reactor technologies. This has motivated the development of more accurate and efficient tools for the design and safety evaluations of the PMR. In addition to the work invested in new methods, it is essential to develop appropriate benchmarks to verify and validate the new methods in computer codes. The purpose of this benchmark is to establish a well-defined problem, based on a common given set of data, to compare methods and tools in core simulation and thermal hydraulics analysis with a specific focus on transient events. The benchmark-working group is currently seeking OECD/NEA sponsorship. This benchmark is being pursued and is heavily based on the success of the PBMR-400 exercise.
Dabiri, John O.
Graduate Aeronautical Laboratories and Bioengineering, California Institute of Technology, Pasadena velocity fixed. It turned out that the pinch-off was always observed to occur at a stroke ratio L time scale for the pinch-off process formation number was tested by generating vortex rings
http://rcc.its.psu.edu/hpc Optimization of a Vortex Finder in a Cyclone Separator using
Bjørnstad, Ottar Nordal
http://rcc.its.psu.edu/hpc Optimization of a Vortex Finder in a Cyclone Separator using Particle of fluidized bed power plants is the cyclone separator. The cyclone separator is used to remove smaller particles, those not large enough for heat transfer, and retain large particles. The cyclone separator
Metlushko, Vitali
Direct observation of superconducting vortex clusters pinned by a periodic array of magnetic dots in ferromagnetic/superconducting hybrid structures T. Shapoval,1,* V. Metlushko,2 M. Wolf,1 B. Holzapfel,1 V. Neu,1, Illinois 60612, USA Received 13 November 2009; published 11 March 2010 Strong pinning of superconducting
Boyer, Edmond
-Einstein condensates Ionut Danaila,a,b , FrÂ´edÂ´eric Hechta,b aUPMC Univ Paris 06, UMR 7598, Laboratoire Jacques Abstract Numerical computations of stationary states of fast-rotating Bose-Einstein condensates require-Einstein condensate, vortex, Sobolev gradient, descent method. 1. Introduction Recent research efforts in the field
Recanati, Catherine
ÂEinstein condensates Ionut Danaila #,a,b , Frâ??edâ??eric Hecht a,b a UPMC Univ Paris 06, UMR 7598, Laboratoire Jacques Abstract Numerical computations of stationary states of fastÂrotating BoseÂEinstein condensates requireÂEinstein condensate, vortex, Sobolev gradient, descent method. 1. Introduction Recent research e#orts in the field
ccsd-00003161,version1-26Oct2004 Vortex patterns in a fast rotating Bose-Einstein condensate
of the rotating gas increases and tends to infinity, and the number of vortices in the condensate diverges [5, 6. Furthermore we restrict our analysis to the case of a two- dimensional gas in the xy plane, assumingccsd-00003161,version1-26Oct2004 Vortex patterns in a fast rotating Bose-Einstein condensate
Godoy-Diana, Ramiro; Aider, Jean-Luc; Wesfreid, José Eduardo
2008-01-01T23:59:59.000Z
The vortex streets produced by a flapping foil of span-to-chord aspect ratio of 4:1 are studied in a hydrodynamic tunnel experiment. In particular, the mechanisms giving rise to the symmetry breaking of the reverse B\\'enard-von K\\'arm\\'an vortex street that characterizes fish-like swimming and forward flapping flight are examined. Two-dimensional particle image velocimetry measurements in the mid-plane perpendicular to the span axis of the foil are used to characterize the different flow regimes. The deflection angle of the mean jet flow with respect to the horizontal observed in the average velocity field is used as a measure of the asymmetry of the vortex street. Time series of the vorticity field are used to calculate the advection velocity of the vortices with respect to the free-stream, defined as the phase velocity $U_{phase}$, as well as the circulation $\\Gamma$ of each vortex and the spacing $\\xi$ between consecutive vortices in the near wake. The observation that the symmetry breaking results from th...
First-Order Transition in the Magnetic Vortex Matter in Superconducting MgB2 Tuned by Disorder
Boyer, Edmond
First-Order Transition in the Magnetic Vortex Matter in Superconducting MgB2 Tuned by Disorder T such as Wigner crystals, charge density waves, magnetic bubble arrays, or vortices in type-II superconductors posi- tional correlations. Vortices in superconductors rapidly became the system of choice
DEFORMATION-BASED NONLINEAR DIMENSION REDUCTION: APPLICATIONS TO NUCLEAR MORPHOMETRY
Gordon, Geoffrey J.
DEFORMATION-BASED NONLINEAR DIMENSION REDUCTION: APPLICATIONS TO NUCLEAR MORPHOMETRY Gustavo K, contrary to common intuition, the most likely nuclear shape configuration is not symmetric. Index Terms-- Nuclear shape analysis, nonlinear, dimension reduction, image registration. 1. INTRODUCTION Under
Overprinting Deformations in Mantle Rocks, Dun Mountain, New Zealand
Donnelly, Sara
2014-04-25T23:59:59.000Z
accommodated deformation (Goetze and Kohlstedt, 1973; Drury and Urai, 1990; Passchier and Trouw, 2005). Intermediate and fine grain size populations formed as a result of recrystallization-accommodated dislocation creep that overprinted, or partially...
Experimental Study on Rock Deformation and Permeability Variation
Ding, Jihui
2013-08-01T23:59:59.000Z
The development of a petroleum reservoir would inevitably induce a rearrangement of the in-situ stress field. The rearrangement of the stress field would then bring about a deformation of the reservoir rock and a change of the permeability...
Self-sorting of deformable particles in a microfluidic circuit
Raafat, Mohamed Salem
2010-01-01T23:59:59.000Z
In this thesis, a new microfluidic device is presented for sorting of deformable particles based on the hydrodynamic resistance induced in a microchannel. Hydrodynamic resistance can be related to physical properties, ...
antebrachial growth deformity: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
boost generator as the corner transfer matrix is briefly discussed. Cesar Gomez; Rafael Hernandez 2007-03-23 35 Deformation in Phase Space Mathematical Physics (arXiv) Summary:...
3D deformation field throughout the interior of materials.
Jin, Huiqing; Lu, Wei-Yang
2013-09-01T23:59:59.000Z
This report contains the one-year feasibility study for our three-year LDRD proposal that is aimed to develop an experimental technique to measure the 3D deformation fields inside a material body. In this feasibility study, we first apply Digital Volume Correlation (DVC) algorithm to pre-existing in-situ Xray Computed Tomography (XCT) image sets with pure rigid body translation. The calculated displacement field has very large random errors and low precision that are unacceptable. Then we enhance these tomography images by setting threshold of the intensity of each slice. DVC algorithm is able to obtain accurate deformation fields from these enhanced image sets and the deformation fields are consistent with the global mechanical loading that is applied to the specimen. Through this study, we prove that the internal markers inside the pre-existing tomography images of aluminum alloy can be enhanced and are suitable for DVC to calculate the deformation field throughout the material body.
anomalously large deformation: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
radiation. I. F. Malov 2007-11-04 88 A study of large plastic deformations in dual phase steel using digital image correlation and FE analysis Physics Websites Summary: ),...
Activation of conductive pathways via deformation-induced instabilities
Ni, Xinchen
2014-01-01T23:59:59.000Z
Inspired by the pattern transformation of periodic elastomeric cellular structures, the purpose of this work is to exploit this unique ability to activate conductive via deformation-induced instabilities. Two microstructural ...
ORIGINAL ARTICLE LEGO-like assembly of peelable, deformable
Rogers, John A.
to the production of an integrated architecture without additional electrical connections. The free technologies that can release mechanical stress has enabled the production of various electronic circuits on non-conven- tional, deformable substrates including plastic, elastomeric rubber, fabric, paper
Minor Groove Deformability of DNA: A Molecular Dynamics Free...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
experimental DNA structures in complex with minor groove-binding proteins. The calculated free energy of minor groove deformation was 4–6 kcal mol-1 in the case of a central...
Kinematic models of interseismic deformation in Southern California
Meade, Brendan J. (Brendan Joseph), 1975-
2004-01-01T23:59:59.000Z
We develop a framework for interpreting geodetic measurements of interseismic deformation and geologic slip rate estimates in terms of block motions. This method accounts for the effects of block rotations and interseismic ...
Fabrication of amorphous metal matrix composites by severe plastic deformation
Mathaudhu, Suveen Nigel
2006-10-30T23:59:59.000Z
Bulk metallic glasses (BMGs) have displayed impressive mechanical properties, but the use and dimensions of material have been limited due to critical cooling rate requirements and low ductility. The application of severe plastic deformation...
Experimental deformation of multilithologic specimens simulating sedimentary facies changes
Dyke, Lawrence Dana
1976-01-01T23:59:59.000Z
EXPERIMENTAL DEFORMATION OF MULTILITHOLOGIC SPECIMENS SIMULATING SEDIMENTARY FACIES CHANGES A Thesis by LAWRENCE DANA DYKE Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1976 Major Subject: Geology EXPERIMENTAL DEFORMATION OF MULTILITHOLOGIC SPECIMENS SIMULATING SEDIMENTARY FACIES CHANGES A Thesis by LAWRENCE DANA DYKE Approved as to style and content by: (Chai n Committee) (Head...
Jordanian deformation of the open XXX-spin chain
P. P. Kulish; N. Manojlovic; Z. Nagy
2009-12-18T23:59:59.000Z
The general solution to the reflection equation associated with the jordanian deformation of the SL(2) invariant Yang R-matrix is found. The same K-matrix is obtained by the special scaling limit of the XXZ-model with general boundary conditions. The Hamiltonian with the boundary terms is explicitly derived according to the Sklyanin formalism. We discuss the structure of the spectrum of the deformed XXX-model and its dependence on the boundary conditions.
TDHF fusion calculations for spherical+deformed systems
A. S. Umar; V. E. Oberacker
2006-04-04T23:59:59.000Z
We outline a formalism to carry out TDHF calculations of fusion cross sections for spherical + deformed nuclei. The procedure incorporates the dynamic alignment of the deformed nucleus into the calculation of the fusion cross section. The alignment results from multiple E2/E4 Coulomb excitation of the ground state rotational band. Implications for TDHF fusion calculations are discussed. TDHF calculations are done in an unrestricted three-dimensional geometry using modern Skyrme force parametrizations.
Effect of nuclear deformation on double beta decay
Rodin, Vadim [Institute fuer Theoretische Physik der Universitaet Tuebingen, D-72076 Tuebingen (Germany)
2009-11-09T23:59:59.000Z
The existing ways of accounting for deformation in recent calculations of neutrinoless double beta decay matrix elements are discussed. From an analysis of relevant experimental data it is argued that only {sup 150}Nd reveals convincing evidences of strong static deformation, which should eventually be taken into account in QRPA calculations. A proposal which allows in principle to measure the neutrino less double beta decay Fermi matrix element is briefly described.
Experimental deformation of multilithologic specimens simulating sedimentary facies changes
Dyke, Lawrence Dana
1976-01-01T23:59:59.000Z
EXPERIMENTAL DEFORMATION OF MULTILITHOLOGIC SPECIMENS SIMULATING SEDIMENTARY FACIES CHANGES A Thesis by LAWRENCE DANA DYKE Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1976 Major Subject: Geology EXPERIMENTAL DEFORMATION OF MULTILITHOLOGIC SPECIMENS SIMULATING SEDIMENTARY FACIES CHANGES A Thesis by LAWRENCE DANA DYKE Approved as to style and content by: (Chai n Committee) (Head...
Non-linear viscoelastic deformation of polymeric solutions
Sanchez Reyes, Javier
2000-01-01T23:59:59.000Z
NON-LINEAR VISCOELASTIC DEFORMATION OF POLYMERIC SOLUTIONS A Thesis by JAVIER SANCHEZ REYES Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... December 2000 Major Subject: Chemical Engineering NON-LINEAR VISCOELASTIC DEFORMATION OF POLYMERIC SOLUTIONS A Thesis by JAVIER SANCHEZ REYES Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of MASTER...
MATERIALS CURRICULUM Major: Core Courses : 21 Credits
Srinivasan, N.
:0 Diffusion in Solids MT 225 3:0 Deformation and Failure Mechanisms at Elevated Temperatures MT 233 3, and nanotechnology. MT 101 3:0 January (4th Semester) Introduction to Materials Science Bonding, types of materials of structural characterization. Thermodynamics of solid solutions, phase diagrams, defects, diffusion
The effect of confinement on the deformation of microfluidic drops
Ulloa, Camilo; Cordero, María Luisa
2013-01-01T23:59:59.000Z
We study the deformation of drops squeezed between the floor and ceiling of a microchannel and subjected to a hyperbolic flow. We observe that the maximum deformation of drops depends on both the drop size and the rate of strain of the external flow and can be described with power laws with exponents 2.59 +/- 0.28 and 0.94 +/- 0.04 respectively. We develop a theoretical model to describe the deformation of squeezed drops based on the Darcy approximation for shallow geometries and the use of complex potentials. The model describes the steady-state deformation of the drops as a function of a non-dimensional parameter Ca d^2, where Ca is the capillary number (proportional to the strain rate and the drop size) and d is a confinement parameter equal to the drop size divided by the channel height. For small deformations, the theoretical model predicts a linear relationship between the deformation of drops and this parameter, in good agreement with the experimental observations.
N=4 Scattering Amplitudes and the Deformed Grassmannian
Livia Ferro; Tomasz Lukowski; Matthias Staudacher
2014-07-24T23:59:59.000Z
Some time ago the general tree-level scattering amplitudes of N=4 Super Yang-Mills theory were expressed as certain Grassmannian contour integrals. These remarkable formulas allow to clearly expose the super-conformal, dual super-conformal, and Yangian symmetries of the amplitudes. Using ideas from integrability it was recently shown that the building blocks of the amplitudes permit a natural multi-parameter deformation. However, this approach had been criticized by the observation that it seemed impossible to reassemble the building blocks into Yangian-invariant deformed non-MHV amplitudes. In this note we demonstrate that the deformations may be succinctly summarized by a simple modification of the measure of the Grassmannian integrals, leading to a Yangian-invariant deformation of the general tree-level amplitudes. Interestingly, the deformed building-blocks appear as residues of poles in the spectral parameter planes. Given that the contour integrals also contain information on the amplitudes at loop-level, we expect the deformations to be useful there as well. In particular, applying meromorphicity arguments, they may be expected to regulate all notorious infrared divergences. We also point out relations to Gelfand hypergeometric functions and the quantum Knizhnik-Zamolodchikov equations.
Van Vliet, Krystyn J.
Size effects on the onset of plastic deformation during nanoindentation of thin films and patterned; accepted 13 August 2003 Plastic deformation of materials exhibits a strong size dependence when, particularly the transition from elastic to plastic deformation and the early stages of plastic deformation. We
DEFORMING MEYER SETS JEONG-YUP LEE AND ROBERT V. MOODY
Moody, Robert Vaughan
DEFORMING MEYER SETS JEONG-YUP LEE AND ROBERT V. MOODY For our friend Ludwig Danzer, on the occasion of his 80th birthday. Abstract. A linear deformation of a Meyer set M in Rd is the image of M and sufficient condition for such a deformation to be a Meyer set. In the case that the deformation is a Meyer