Sample records for antiferromagnetic vortex states

  1. Direct Imaging of Antiferromagnetic Vortex States

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  2. Direct Imaging of Antiferromagnetic Vortex States

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  3. Direct Imaging of Antiferromagnetic Vortex States

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  4. Direct Imaging of Antiferromagnetic Vortex States

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  5. Direct Imaging of Antiferromagnetic Vortex States

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  6. Direct Imaging of Antiferromagnetic Vortex States

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  7. Direct Imaging of Antiferromagnetic Vortex States

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  8. Direct Imaging of Antiferromagnetic Vortex States

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  9. Theory of static and dynamic antiferromagnetic vortices in LSCO superconductors

    E-Print Network [OSTI]

    Hu, Jiangping

    Theory of static and dynamic antiferromagnetic vortices in LSCO superconductors Jiang-Ping Hu, Shou scattering experiment on LSCO superconductors revealed enhanced antiferromagnetic order in the vortex state and dynamic antiferromanetic vortices in LSCO superconductors. It is shown that the antiferromagnetic region

  10. A numerical study of steady-state vortex configurations and vortex pinning in type-II superconductors

    E-Print Network [OSTI]

    Kim, Sangbum

    2006-04-12T23:59:59.000Z

    are presented. Transitions between different multi-vortex states as H is changed is demonstrated by abrupt changes in vortex configurations and jumps in the B vs H plot. An efficient scheme to determine the equilibrium vortex configuration in a mesoscopic system...

  11. Dissipative dynamics of a vortex state in a trapped Bose-condensed gas

    E-Print Network [OSTI]

    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.

  12. Steady-state and equilibrium vortex configurations, transitions, and evolution in a mesoscopic superconducting cylinder

    E-Print Network [OSTI]

    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...

  13. Entanglement spectrum: Identification of the transition from vortex-liquid to vortex-lattice state in a weakly interacting rotating Bose-Einstein condensate

    SciTech Connect (OSTI)

    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.

  14. Vortex state in a doped Mott insulator M. Franz and Z. Tesanovic

    E-Print Network [OSTI]

    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

  15. Axisymmetric-coherent-vortex states in current-driven Josephson-junction arrays

    SciTech Connect (OSTI)

    Dominguez, D.; Jose, J.V. (Physics Department, Northeastern University, Boston, Massachusetts 02115 (United States))

    1993-11-01T23:59:59.000Z

    We present results from an extensive analysis of the dynamic response of Josephson-junction arrays driven by external currents of the form [ital I]=[ital I][sub dc]+[ital I][sub ac]sin(2[pi][nu][ital t]). The dynamics is given by the resistively shunted Josephson-junction model with Johnson noise. We find a stationary [ital axisymmetric][minus][ital coherent][minus][ital vortex] [ital state] (ACVS) away from equilibrium and above a minimum lattice size ([similar to]20[times]20) whenever the initial state has at least one antivortex and a vortex. The ACVS is characterized by tilted rows of oscillating positive and negative vortices, produced by the combined effect of the driving current plus the collective coupling of the nonlinear Josephson oscillators. The ACVS is manifested in the current-voltage characteristics as giant half-integer Shapiro steps, leading to period-two resonances in the spectral function. The stability and properties of the ACVS are studied as a function of frequency, temperature, disorder, edge magnetic fields, and lattice sizes. It is found that the ACVS is a very robust two-dimensional dynamical state that is produced under very diverse circumstances. A connection between the ACVS and half-integer steps seen in proximity effect arrays in zero field is also discussed.

  16. Non-equilibrium coherent vortex states and subharmonic giant Shapiro steps in Josephson junction arrays

    E-Print Network [OSTI]

    Daniel Domínguez; Jorge V. José

    1994-07-11T23:59:59.000Z

    This is a review of recent work on the dynamic response of Josephson junction arrays driven by dc and ac currents. The arrays are modeled by the resistively shunted Josephson junction model, appropriate for proximity effect junctions, including self-induced magnetic fields as well as disorder. The relevance of the self-induced fields is measured as a function of a parameter $\\kappa=\\lambda_L/a$, with $\\lambda_L$ the London penetration depth of the arrays, and $a$ the lattice spacing. The transition from Type II ($\\kappa>1$) to Type I ($\\kappa <1$) behavior is studied in detail. We compare the results for models with self, self+nearest-neighbor, and full inductance matrices. In the $\\kappa=\\infty$ limit, we find that when the initial state has at least one vortex-antivortex pair, after a characteristic transient time these vortices unbind and {\\it radiate} other vortices. These radiated vortices settle into a parity-broken, time-periodic, {\\em axisymmetric coherent vortex state} (ACVS), characterized by alternate rows of positive and negative vortices lying along a tilted axis. The ACVS produces subharmonic steps in the current voltage (IV) characteristics, typical of giant Shapiro steps. For finite $\\kappa$ we find that the IV's show subharmonic giant Shapiro steps, even at zero external magnetic field. We find that these subharmonic steps are produced by a whole family of coherent vortex oscillating patterns, with their structure changing as a function of $\\kappa$. In general, we find that these patterns are due to a break down of translational invariance produced, for example, by disorder or antisymmetric edge-fields. The zero field case results are in good qualitative agreement with experiments

  17. A finite element method with mesh adaptivity for computing vortex states in fast-rotating Bose-Einstein condensates

    E-Print Network [OSTI]

    Boyer, Edmond

    -Einstein condensates Ionut Danaila,a,b , Fr´ed´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

  18. A finite element method with mesh adaptivity for computing vortex states in fastrotating BoseEinstein condensates

    E-Print Network [OSTI]

    Recanati, Catherine

    ­Einstein 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 fast­rotating Bose­Einstein condensates require­Einstein condensate, vortex, Sobolev gradient, descent method. 1. Introduction Recent research e#orts in the field

  19. Analytic treatment of vortex states in cylindrical superconductors in applied axial magnetic field

    SciTech Connect (OSTI)

    Ludu, A. [Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium); Department of Chemistry and Physics, Northwestern State University, Natchitoches, Louisiana 71497 (United States); Van Deun, J.; Cuyt, A. [Departement Wiskunde-Informatica, Universiteit Antwerpen, Middelheimlaan 1, B-2020 Antwerpen (Belgium); Milosevic, M. V.; Peeters, F. M. [Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium)

    2010-08-15T23:59:59.000Z

    We solve the linear Ginzburg-Landau (GL) equation in the presence of a uniform magnetic field with cylindrical symmetry and we find analytic expressions for the eigenfunctions in terms of the confluent hypergeometric functions. The discrete spectrum results from an implicit equation associated to the boundary conditions and it is resolved in analytic form using the continued fractions formalism. We study the dependence of the spectrum and the eigenfunctions on the sample size and the surface conditions for solid and hollow cylindrical superconductors. Finally, the solutions of the nonlinear GL formalism are constructed as expansions in the linear GL eigenfunction basis and selected by minimization of the free energy. We present examples of vortex states and their energies for different samples in enhancing/suppressing superconductivity surroundings.

  20. Zero-energy states bound to a magnetic pi-flux vortex in a two-dimensional topological insulator

    E-Print Network [OSTI]

    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.

  1. All-optical discrete vortex switch

    SciTech Connect (OSTI)

    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.

  2. Crystalline Electric Field as a Probe for Long-Range Antiferromagnetic Order and Superconducting State of CeFeAsO1-xFx

    SciTech Connect (OSTI)

    Chi, Songxue [University of Tennessee, Knoxville (UTK); Adroja, D. T. [ISIS Facility, Rutherford Appleton Laboratory; GUIDI, T. [ISIS Facility, Rutherford Appleton Laboratory; Bewley, Robert I. [ISIS Facility, Rutherford Appleton Laboratory; Li, Shiliang [University of Tennessee, Knoxville (UTK); Zhao, Jun [ORNL; Lynn, J. W. [National Institute of Standards and Technology (NIST); Brown, C. M. [National Institute of Standards and Technology (NIST); Qiu, Y. [National Institute of Standards and Technology (NIST); Chen, G. F, [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics; Luo, J. L. [Chinese Academy of Sciences; Wang, N. L. [Chinese Academy of Sciences; Dai, Pengcheng [ORNL

    2008-01-01T23:59:59.000Z

    We use inelastic neutron scattering to study the crystalline electric field (CEF) excitations of Ce{sup 3+} in CeFeAsO{sub 1-x}F{sub x} (x=0, 0.16). For nonsuperconducting CeFeAsO, the Ce CEF levels have three magnetic doublets in the paramagnetic state, but these doublets split into six singlets when the Fe ions order antiferromagnetically. For superconducting CeFeAsO{sub 0.84}F{sub 0.16} (T{sub c} = 41 K), where the static antiferromagnetic order is suppressed, the Ce CEF levels have three magnetic doublets at {h_bar}{sub {omega}} = 0, 18.7, 58.4 meV at all temperatures. Careful measurements of the intrinsic linewidth {Lambda} and the peak position of the 18.7 meV mode reveal a clear anomaly at T{sub c}, consistent with a strong enhancement of local magnetic susceptibility {chi}{double_prime}({h_bar}{sub {omega}}) below T{sub c}. These results suggest that CEF excitations in the rare-earth oxypnictides can be used as a probe of spin dynamics in the nearby FeAs planes.

  3. E-Print Network 3.0 - antiferromagnetic potts models Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    "Antiferromagnetic Ordering in the Three-State Potts Model", J. Phys. A10... , M.P. Nightingale, and M. Schick, "Critical Fan in the Antiferromagnetic Three-State Potts Model... ,...

  4. Piezo-antiferromagnetic effect of sawtooth-like graphene nanoribbons

    SciTech Connect (OSTI)

    Zhao, Shangqian; Lu, Yan; Zhang, Yuchun; Lu, Wengang, E-mail: wglu@iphy.ac.cn; Liang, Wenjie [Institute of Physics, Chinese Academy of Sciences/Beijing National Laboratory for Condensed Matter Physics, Beijing 100190 (China); Wang, Enge [International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871 (China)

    2014-05-19T23:59:59.000Z

    A type of sawtooth-like graphene nanoribbon (SGNR) with piezo-antiferromagnetic effect is studied numerically. The ground state of the studied SGNR changes from nonmagnetic state to antiferromagnetic state with uniaxial strain. The changes of the spin-charge distributions during the stretching are investigated. The Hubbard model reveals that the hopping integrals between the ?-orbitals of the carbon atoms are responsible to the piezo-antiferromagnetic effect. The study sheds light on the application of graphene-based structures to nanosensors and spintronic devices.

  5. Antiferromagnetic domain size and exchange bias

    E-Print Network [OSTI]

    Fitzsimmons, M. R.; Lederman, D.; Cheon, M.; Shi, H.; Olamit, J.; Roshchin, Igor V.; Schuller, Ivan K.

    2008-01-01T23:59:59.000Z

    Using neutron diffraction, we measured the sizes of antiferromagnetic domains in three ferromagnet/antiferromagnet bilayer samples as a function of the magnitude and sign of exchange bias, temperature, and antiferromagnet composition. Neutron...

  6. RESTRICTED-TRACE APPROXIMATION FOR NUCLEAR ANTIFERROMAGNETISM

    E-Print Network [OSTI]

    Boyer, Edmond

    1353 RESTRICTED-TRACE APPROXIMATION FOR NUCLEAR ANTIFERROMAGNETISM M. GOLDMAN and G. SARMA Service to predict several properties of nuclear antiferromagnetic structures : sublattice magnetization of nuclear dipolar magnetic ordering, either antiferromagnetic or ferromagnetic, has been reported

  7. Novel Magnetic Hydrogen Sensing: A Case Study Using Antiferromagnetic...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetic Hydrogen Sensing: A Case Study Using Antiferromagnetic Hematite Nanoparticles. Novel Magnetic Hydrogen Sensing: A Case Study Using Antiferromagnetic Hematite...

  8. Antiferromagnet-based nuclear spin model of scalable quantum register with inhomogeneous magnetic field

    E-Print Network [OSTI]

    A. A. Kokin; V. A. Kokin

    2008-12-01T23:59:59.000Z

    As a nuclear spin model of scalable quantum register, the one-dimensional chain of the magnetic atoms with nuclear spins 1/2 substituting the basic atoms in the plate of nuclear spin free easy-axis 3D antiferromagnet is considered. It is formulated the generalized antiferromagnet Hamiltonian in spin-wave approximation (low temperatures) considering the inhomogeneous external magnetic field, which is directed along the easy axis normally to plane of the plate and has a constant gradient along the nuclear spin chain. Assuming a weak gradient, the asymptotic expression for coefficients of unitary transformations to the diagonal form of antiferromagnet Hamiltonian is found. With this result the expression for indirect interspin coupling, which is due to hyperfine nuclear electron coupling in atoms and the virtual spin wave propagation in antiferromagnet ground state, was evaluated. It is shown that the inhomogeneous magnetic field essentially modifies the characteristics of indirect interspin coupling. The indirect interaction essentially grows and even oscillates in relation to the interspin distance when the local field value in the middle point of two considered nuclear spin is close to the critical field for quantum phase transition of spin-flop type in bulk antiferromagnet or close to antiferromagnetic resonance. Thus, the external magnetic field, its gradient, microwave frequency and power can play the role of control parameters for qubit states. Finally, the one and two qubit states decoherence and longitudinal relaxation rate are caused by the interaction of nuclear spins with virtual spin waves in antiferromagnet ground state are calculated.

  9. Phases of Atom-Molecule Vortex Matter

    SciTech Connect (OSTI)

    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.

  10. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    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...

  11. Improved vortex reactor system

    DOE Patents [OSTI]

    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.

  12. Vortex diode jet

    DOE Patents [OSTI]

    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.

  13. Dynamic decay of a single vortex into vortex-antivortex pairs

    SciTech Connect (OSTI)

    Lendínez, Sergi [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Universidad Barcelona, Departamento Fisica Fonamental, E-08028 Barcelona (Spain); Jain, Shikha; Novosad, Valentyn, E-mail: novosad@anl.gov; Fradin, Frank Y.; Pearson, John E. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Tejada, Javier [Universidad Barcelona, Departamento Fisica Fonamental, E-08028 Barcelona (Spain); Bader, Samuel D. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2014-05-07T23:59:59.000Z

    A variety of metastable states, including vortices, antivortices, and their combinations, is typical for magnetically soft, thin films and patterned structures. The physics of individual spin vortices in patterned structures has been rather extensively explored. In contrast, there are few studies of the vortex–antivortex–vortex (v-av-v) system, in part because the configuration is rather challenging to obtain experimentally. We demonstrate herein how a recently proposed resonant-spin-ordering technique can be used to induce the dynamic decay of a single vortex into v-av states in elongated elements. The approach is based on first driving the system from the linear regime of constant vortex gyrations to the non-linear regime of vortex-core reversals at a fixed excitation frequency, and then subsequently reducing the excitation field back to the linear regime. This procedure stabilizes the system into a v-av-v state that is completely decoupled from the initialization excitation frequency. The newly acquired state is stable in remanence. The dynamic response of this system is expected to demonstrate a number of collective modes, depending on the combination of the vortex core polarities, and/or the excitation field direction, and, hence, is of interest for future studies.

  14. Bifurcation to vortex solutions in superconducting lms

    E-Print Network [OSTI]

    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

  15. ENERGY LEVEL SPECTROSCOPY OF A BOUND VORTEX-ANTIVORTEX PAIR

    E-Print Network [OSTI]

    Wallraff, Andreas

    vortex- antivortex (VAV) state in an annular Josephson junction. The bound VAV pair is formed microwave spectroscopy. Keywords: Macroscopic quantum effects, long Josephson junctions, vortex­9]. Most of the studied systems, such as dc-biased Josephson junctions (JJ), supercon- ducting quantum

  16. The effect of Au and Ni doping on the heavy fermion state of the Kondo lattice antiferromagnet CePtZn

    SciTech Connect (OSTI)

    Dhar, S. K., E-mail: sudesh@tifr.res.in [DCMPMS, T.I.F.R., Homi Bhabha Road, Colaba, Mumbai 400005 (India); Aoki, Y.; Suemitsu, B.; Miyazaki, R. [Department of Physics, Tokyo Metropolitan University, Minami-Ohsawa 1-1, Hachioji-Shi, Tokyo (Japan); Provino, A.; Manfrinetti, P. [Departimento Physica Chemicale, Universita di Genova, Via Dodecaneso, 16146 Genova (Italy)

    2014-05-07T23:59:59.000Z

    We have probed the effect of doping CePtZn with Au and Ni and also investigated in detail the magnetic behavior of the iso-structural CeAuZn. A magnetic ground state is observed in both CePt{sub 0.9}Au{sub 0.1}Zn and CePt{sub 0.9}Ni{sub 0.1}Zn with T{sub N}?=?2.1 and 1.1?K and the coefficient of the linear term of electronic heat capacity ??=?0.34 and 0.9?J/mol K{sup 2}, respectively. The corresponding values for CePtZn are 1.7?K and 0.6?J/mol K{sup 2}. The altered values of T{sub N} and ? show that the electronic correlations in CePtZn are affected by doping with Au and Ni. CeAuZn orders magnetically near 1.7?K and its electrical resistivity shows a normal metallic behavior. Together with a ? of 0.022?J/mol K{sup 2} the data indicate a weak 4f-conduction electron hybridization in CeAuZn characteristic of normal trivalent cerium based systems.

  17. Adiabatic Preparation of a Heisenberg Antiferromagnet Using an Optical Superlattice

    E-Print Network [OSTI]

    Michael Lubasch; Valentin Murg; Ulrich Schneider; J. Ignacio Cirac; Mari-Carmen Bañuls

    2011-11-06T23:59:59.000Z

    We analyze the possibility to prepare a Heisenberg antiferromagnet with cold fermions in optical lattices, starting from a band insulator and adiabatically changing the lattice potential. The numerical simulation of the dynamics in 1D allows us to identify the conditions for success, and to study the influence that the presence of holes in the initial state may have on the protocol. We also extend our results to two-dimensional systems.

  18. Adiabatic preparation of a Heisenberg antiferromagnet using an optical superlattice

    E-Print Network [OSTI]

    Lubasch, Michael; Schneider, Ulrich; Cirac, J Ignacio; Bañuls, Mari-Carmen

    2011-01-01T23:59:59.000Z

    We analyze the possibility to prepare a Heisenberg antiferromagnet with cold fermions in optical lattices, starting from a band insulator and adiabatically changing the lattice potential. The numerical simulation of the dynamics in 1D allows us to identify the conditions for success, and to study the influence that the presence of holes in the initial state may have on the protocol. We also extend our results to two-dimensional systems.

  19. Electron vortex beams in a magnetic field and spin filter

    E-Print Network [OSTI]

    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.

  20. Improved vortex reactor system

    DOE Patents [OSTI]

    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.

  1. The Holographic Superconductor Vortex

    E-Print Network [OSTI]

    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.

  2. Nested Cluster Algorithm for Frustrated Quantum Antiferromagnets

    E-Print Network [OSTI]

    M. Nyfeler; F. -J. Jiang; F. Kämpfer; U. -J. Wiese

    2008-03-25T23:59:59.000Z

    Simulations of frustrated quantum antiferromagnets suffer from a severe sign problem. We solve the ergodicity problem of the loop-cluster algorithm in a natural way and apply a powerful strategy to address the sign problem. For the spin 1/2 Heisenberg antiferromagnet on a kagome and on a frustrated square lattice, a nested cluster algorithm eliminates the sign problem for large systems. The method is applicable to general lattice geometries but limited to moderate temperatures.

  3. Vortex Characterization for Engineering Applications

    SciTech Connect (OSTI)

    Jankun-Kelly, M; Thompson, D S; Jiang, M; Shannahan, B; Machiraju, R

    2008-01-30T23:59:59.000Z

    Realistic engineering simulation data often have features that are not optimally resolved due to practical limitations on mesh resolution. To be useful to application engineers, vortex characterization techniques must be sufficiently robust to handle realistic data with complex vortex topologies. In this paper, we present enhancements to the vortex topology identification component of an existing vortex characterization algorithm. The modified techniques are demonstrated by application to three realistic data sets that illustrate the strengths and weaknesses of our approach.

  4. PHYSICAL REVIEW B 88, 085406 (2013) Topological insulators with commensurate antiferromagnetism

    E-Print Network [OSTI]

    Gilbert, Matthew

    2013-01-01T23:59:59.000Z

    PHYSICAL REVIEW B 88, 085406 (2013) Topological insulators with commensurate antiferromagnetism of the surface states of a 3D topological insulator in the presence of AFM fields with different propagation in the system.1 Nevertheless, the vast majority of topological band insulator states that have been

  5. antiferromagnetic materials: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    antiferromagnetic materials First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Antiferromagnetism in...

  6. antiferromagnet-based nuclear spin: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    antiferromagnet-based nuclear spin First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 The qubit states...

  7. Variable residence time vortex combustor

    DOE Patents [OSTI]

    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.

  8. Vortex patterns and infinite degeneracy in the uniformly frustrated XY models and lattice Coulomb gas

    E-Print Network [OSTI]

    Lee, Jooyoung

    Vortex patterns and infinite degeneracy in the uniformly frustrated XY models and lattice Coulomb gas Myoung Kwan Ko,1 Sung Jong Lee,2 Jooyoung Lee,3 and Bongsoo Kim4 1 Department of Physics, Konkuk state vortex con- figurations of a uniformly frustrated XY model on a square lattice for cases

  9. Efficiently computing vortex lattices in fast rotating Bose-Einstein condensates Yanzhi Zhang1,2

    E-Print Network [OSTI]

    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

  10. antiferromagnetic spin fluctuations: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to its bare value over some Chubukov, Andrey V. 3 Spin fragmentation of BoseEinstein condensates with antiferromagnetic interactions Physics Websites Summary: of an...

  11. Pinning-modulated non-collective Josephson-vortex motion in stacked Josephson junctions.

    SciTech Connect (OSTI)

    Jin, Y.-D.; Lee, G.-H.; Lee, H.-J.; Bae, M.-H.; Koshelev, A. E.; Pohang Univ. of Science and Technology; Univ. of Illinois

    2009-01-01T23:59:59.000Z

    Josephson vortices in naturally stacked Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} tunneling junctions display rich dynamic behavior that derives from the coexistence of three basic states: static Josephson vortex lattice, coherently moving lattice, and incoherent quasiparticle tunneling state. The rich structure of hysteretic branches observed in the current-voltage characteristics can be understood as combinatorial combinations of these three states which are realized in different junctions and evolve separately with magnetic field and bias current. In particular, the multiple Josephson vortex flow branches at low-bias currents arise from the individual depinning of Josephson vortex rows in each junction.

  12. Vortex lattice for a holographic superconductor

    E-Print Network [OSTI]

    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.

  13. Detecting antiferromagnetism of atoms in an optical lattice via optical Bragg scattering

    SciTech Connect (OSTI)

    Corcovilos, T. A.; Hitchcock, J. M.; Hulet, R. G. [Department of Physics and Astronomy, and Rice Quantum Institute, Rice University, Houston, Texas 77005 (United States); Baur, S. K.; Mueller, E. J. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853 (United States)

    2010-01-15T23:59:59.000Z

    Antiferromagnetism of ultracold fermions in an optical lattice can be detected by Bragg diffraction of light, in analogy to the diffraction of neutrons from solid-state materials. A finite sublattice magnetization will lead to a Bragg peak from the ((1/2)(1/2)(1/2)) crystal plane with an intensity depending on details of the atomic states, the frequency and polarization of the probe beam, the direction and magnitude of the sublattice magnetization, and the finite optical density of the sample. Accounting for these effects we make quantitative predictions about the scattering intensity and find that with experimentally feasible parameters the signal can be readily measured with a CCD camera or a photodiode and used to detect antiferromagnetic order.

  14. Vortex Structure in Charged Condensate

    E-Print Network [OSTI]

    Gabadadze, Gregory

    2009-01-01T23:59:59.000Z

    We study magnetic fields in the charged condensate that we have previously argued should be present in helium-core white dwarf stars. We show that below a certain critical value the magnetic field is entirely expelled from the condensate, while for larger values it penetrates the condensate within flux-tubes that are similar to Abrikosov vortex lines; yet higher fields lead to the disruption of the condensate. We find the solution for the vortex lines in both relativistic and nonrelativistic theories that exhibit the charged condensation. We calculate the energy density of the vortex solution and the values of the critical magnetic fields. The minimum magnetic field required for vortices to penetrate the helium white dwarf cores ranges from roughly 10^7 to 10^9 Gauss. Fields of this strength have been observed in white dwarfs. We also calculate the London magnetic field due to the rotation of a dwarf star and show that its value is rather small.

  15. Vortex Structure in Charged Condensate

    E-Print Network [OSTI]

    Gregory Gabadadze; Rachel A. Rosen

    2009-05-14T23:59:59.000Z

    We study magnetic fields in the charged condensate that we have previously argued should be present in helium-core white dwarf stars. We show that below a certain critical value the magnetic field is entirely expelled from the condensate, while for larger values it penetrates the condensate within flux-tubes that are similar to Abrikosov vortex lines; yet higher fields lead to the disruption of the condensate. We find the solution for the vortex lines in both relativistic and nonrelativistic theories that exhibit the charged condensation. We calculate the energy density of the vortex solution and the values of the critical magnetic fields. The minimum magnetic field required for vortices to penetrate the helium white dwarf cores ranges from roughly 10^7 to 10^9 Gauss. Fields of this strength have been observed in white dwarfs. We also calculate the London magnetic field due to the rotation of a dwarf star and show that its value is rather small.

  16. Fragile antiferromagnetism in the heavy-fermion compound YbBiPt

    SciTech Connect (OSTI)

    Ueland, Benjamin G. [Ames Laboratory; Kreyssig, Andreas [Ames Laboratory; Prokes, K. [Helmholtz-Zentrum Berlin fur Materialien und Energie; Lynn, J. W. [NIST Center for Neutron Research; Harriger, L. W. [NIST Center for Neutron Research; Pratt, D. K. [NIST Center for Neutron Research; Singh, D. K. [NIST Center for Neutron Research; Heitmann, T. W. [University of Missouri; Sauerbrei, Samantha [Ames Laboratory; Saunders, Scott M. [Ames Laboratory; Mun, E. D. [Ames Laboratory; Budko, Serguei L. [Ames Laboratory; McQueeney, Robert J. [Ames Laboratory; Canfield, Paul C. [Ames Laboratory; Goldman, Alan I. [Ames Laboratory

    2014-05-08T23:59:59.000Z

    We report results from neutron scattering experiments on single crystals of YbBiPt that demonstrate antiferromagnetic order characterized by a propagation vector, ?AFM = (121212), and ordered moments that align along the [1 1 1] direction of the cubic unit cell. We describe the scattering in terms of a two-Gaussian peak fit, which consists of a narrower component that appears below TN?0.4 K and corresponds to a magnetic correlation length of ?n? 80 Å, and a broad component that persists up to T?? 0.7 K and corresponds to antiferromagnetic correlations extending over ?b? 20 Å. Our results illustrate the fragile magnetic order present in YbBiPt and provide a path forward for microscopic investigations of the ground states and fluctuations associated with the purported quantum critical point in this heavy-fermion compound.

  17. Onset of superradiant instabilities in the hydrodynamic vortex model

    E-Print Network [OSTI]

    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.

  18. Inhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates

    E-Print Network [OSTI]

    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...

  19. Excitation spectrum of a model antiferromagnetic spin-trimer.

    SciTech Connect (OSTI)

    Stone, Matthew B [ORNL; Fernandez-Alonso, F. [ISIS Facility, Rutherford Appleton Laboratory; Adroja, D. T. [ISIS Facility, Rutherford Appleton Laboratory; Dalal, N. S. [Florida State University; Villagran, D. [Texas A& M University; Cotton, F. A. [Texas A& M University; Nagler, Stephen E [ORNL

    2007-01-01T23:59:59.000Z

    We present an inelastic neutron scattering (INS) study of the excitation spectrum of a quantum S=1/2 equilateral Heisenberg trimer, Cu{sub 3}(O{sub 2}C{sub 16}H{sub 23}){sub 61.2}C{sub 6}H{sub 12}. The magnetic properties of the system can be described by an ensemble of independent equilateral triangles of S=1/2 Cu{sup 2+} ions. With antiferromagnetic Heisenberg coupling, the ground state of each trimer is a degenerate pair of S=1/2 doublets, with a quartet S=3/2 excited state. Previous bulk measurements led to an estimate for the excitation energy of 28 meV. Here, we report INS measurements that can provide a direct measurement of magnetic excitation energies. These measurements are challenging since inter- and intramolecular vibrational modes associated with the organic ligands are at frequencies similar to the magnetic excitations. Measurements on a nonmagnetic compound with the same ligands as well as the temperature dependence of the neutron scattering cross section are used to identify the vibrational modes. This leads to an identification of the magnetic excitation energy as being approximately 37 meV at T=10 K, with a gradual softening with increasing temperature.

  20. Giant magnetic effects and oscillations in antiferromagnetic Josephson weak links

    SciTech Connect (OSTI)

    Gorkov, L.; Kresin, Vladimir

    2001-04-01T23:59:59.000Z

    Josephson junctions with an antiferromagnetic metal as a link are described. The junction can be switched off by a relatively small magnetic field. The amplitude of the current oscillates as a function of the field.

  1. Kinetically Inhibited Order in a Diamond-Lattice Antiferromagnet

    SciTech Connect (OSTI)

    MacDougall, Gregory J [ORNL; Gout, Delphine J [ORNL; Zarestky, Jerel L [ORNL; Ehlers, Georg [ORNL; Podlesnyak, Andrey A [ORNL; McGuire, Michael A [ORNL; Mandrus, David [ORNL; Nagler, Stephen E [ORNL

    2011-01-01T23:59:59.000Z

    Frustrated magnetic systems exhibit highly degenerate ground states and strong fluctuations, often leading to new physics. An intriguing example of current interest is the antiferromagnet on a diamond lattice, realized physically in the A-site spinel materials. This is a prototypical system in three dimensions where frustration arises from competing interactions rather than purely geometric constraints, and theory suggests the possibility of novel order at low temperature. Here we present a comprehensive single crystal neutron scattering study CoAl2O4, a highly frustrated A-site spinel. We observe strong diffuse scattering that peaks at wavevectors associated with Neel ordering. Below the temperature T*=6.5K, there is a dramatic change in elastic scattering lineshape accompanied by the emergence of well-defined spin-wave excitations. T* had previously been associated with the onset of glassy behavior. Our new results suggest instead that in fact T* signifies a first-order phase transition, but with true long-range order inhibited by the kinetic freezing of domain walls. This scenario might be expected to occur widely in frustrated systems containing first-order phase transitions and is a natural explanation for existing reports of anomalous glassy behavior in other materials.

  2. Reconnection of vortex filaments and Kolmogorov spectrum

    E-Print Network [OSTI]

    Nemirovskii, Sergey K

    2014-01-01T23:59:59.000Z

    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...

  3. Superconducting vortex pinning with artificially prepared nanostructures

    E-Print Network [OSTI]

    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

  4. Vortex Hydro Energy Develops Transformational Technology to Harness...

    Energy Savers [EERE]

    Vortex Hydro Energy Develops Transformational Technology to Harness Energy from Water Currents Vortex Hydro Energy Develops Transformational Technology to Harness Energy from Water...

  5. Light propagation around a relativistic vortex flow of dielectric medium

    E-Print Network [OSTI]

    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.

  6. Magnetoelastic Coupling and Symmetry Breaking in the Frustrated Antiferromagnet {alpha}-NaMnO{sub 2}

    SciTech Connect (OSTI)

    Giot, Maud [Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Vassilika Vouton, 71110 Heraklion (Greece); ISIS, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton-Didcot, OX11 0QX, Oxfordshire (United Kingdom); Chapon, Laurent C.; Radaelli, Paolo G. [ISIS, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton-Didcot, OX11 0QX, Oxfordshire (United Kingdom); Androulakis, John; Lappas, Alexandros [Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Vassilika Vouton, 71110 Heraklion (Greece); Green, Mark A. [NIST Center for Neutron Research, 100 Bureau Drive, Gaithersburg, Maryland 20899-8562 (United States); Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742-2115 (United States)

    2007-12-14T23:59:59.000Z

    The magnetic and crystal structures of the {alpha}-NaMnO{sub 2} have been determined by high-resolution neutron powder diffraction. The system maps out a frustrated triangular spin lattice with anisotropic interactions that displays two-dimensional spin correlations below 200 K. Magnetic frustration is lifted through magneto-elastic coupling, evidenced by strong anisotropic broadening of the diffraction profiles at high temperature and ultimately by a structural phase transition at 45 K. In this low-temperature regime a three-dimensional antiferromagnetic state is observed with a propagation vector k=((1/2),(1/2),0)

  7. Antiferromagnetic ordering in NdAuGe compound

    SciTech Connect (OSTI)

    Bashir, A. K. H.; Tchoula Tchokonté, M. B., E-mail: mtchokonte@uwc.ac.za [Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Snyman, J. L.; Sondezi, B. M.; Strydom, A. M. [Department of Physics, University of Johannesburg, Auckland Park 2006 (South Africa)

    2014-05-07T23:59:59.000Z

    The compound NdAuGe was investigated by means of electrical resistivity, ?(T), magnetic susceptibility, ?(T), magnetization, ?(?{sub 0}H), and specific heat, C{sub p}(T), measurements. Powder X-ray diffraction studies confirm a hexagonal LiGaGe-type structure with space group P6{sub 3}mc (No. 186). ?(T) data show normal metallic behaviour and a tendency toward saturation at higher temperatures. The low temperature ?(T) data indicate a phase transition around 3.8?K. The low field dc ?(T) data show an antiferromagnetic anomaly associated with a Néel temperature at T{sub N}?=?3.7?K close to the phase transition observed in ?(T) results. At higher temperatures, ?(T) follows the paramagnetic Curie-Weiss behaviour with an effective magnetic moment ?{sub eff}=3.546(4)??{sub B} and a paramagnetic Weiss temperature of ?{sub p}=?6.1(4)?K. The value obtained for ?{sub eff} is close to the value of 3.62??{sub B} expected for the free Nd{sup 3+}-ion. ?(?{sub 0}H) shows a linear behaviour with applied field up to 3?T with an evidence of metamagnetic behaviour above 3?T. C{sub p}(T) confirms the magnetic phase transition at T{sub N}?=?3.4?K. The 4f-electron specific heat indicates a Schottky-type anomaly around 16.5?K with energy splitting ?{sub 1}=25.8(4) K and ?{sub 2}=50.7(4) K of the Nd{sup 3+}?(J?=?9/2) multiplet, that are associated with, respectively, the first and second excited states of the Nd{sup 3+}-ion.

  8. The idea of vortex energy

    E-Print Network [OSTI]

    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.

  9. Ergoregion instability: The hydrodynamic vortex

    E-Print Network [OSTI]

    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.

  10. Vortex pinning by inhomogeneities in type-II superconductors

    E-Print Network [OSTI]

    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

  11. Stability of vortex solitons in a photorefractive optical lattice

    E-Print Network [OSTI]

    Yang, Jianke

    ://www.njp.org/ DOI: 10.1088/1367-2630/6/1/047 Abstract. Stability of on- and off-site vortex solitons with unit stable than off-site ones. Increasing the DC field stabilizes both types of vortex solitons. Contents 1. Introduction 2 2. Off-site vortex solitons 4 3. On-site vortex solitons 9 4. Summary 11 Acknowledgments 11

  12. Memory-bit selection and recording by rotating fields in vortex-core cross-point architecture

    SciTech Connect (OSTI)

    Yu, Y. -S.; Jung, H.; Lee, K. -S.; Fischer, P.; Kim, S. -K.

    2010-10-21T23:59:59.000Z

    In one of our earlier studies [Appl. Phys. Lett. 92, 022509 (2008)], we proposed a concept of robust information storage, recording and readout, which can be implementaed in nonvolatile magnetic random-access memories and is based on the energetically degenerated twofold ground states of vortex-core magnetizations. In the present study, we experimentally demonstrate reliable memory-bit selection and information recording in vortex-core cross-point architecture, specifically using a two-by-two vortex-state disk array. In order to efficiently switch a vortex core positioned at the intersection of crossed electrodes, two orthogonal addressing electrodes are selected, and then two Gaussian pulse currents of optimal pulse width and time delay are applied. Such tailored pulse-type rotating magnetic fields which occurs only at the selected intersection is prerequisite for a reliable memory-bit selection and low-power-consumption recording of information in the existing cross-point architecture.

  13. Josephson vortex lattice in layered superconductors

    SciTech Connect (OSTI)

    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.

  14. The Life of a Vortex Knot

    E-Print Network [OSTI]

    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.

  15. The multiple vortex nature of tropical cyclogenesis

    E-Print Network [OSTI]

    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...

  16. Airfoil Vortex Induced Vibration suppression devices

    E-Print Network [OSTI]

    Lee, Evan J. (Evan Joseph)

    2007-01-01T23:59:59.000Z

    Vortex Induced Vibrations (VIV) is a major concern of the offshore oil industry. This problem leads to fatigue failure in the marine risers and causes costly replacement of the risers. Appendages such as helical strakes ...

  17. A reduced Blade-Vortex Interaction rotor

    E-Print Network [OSTI]

    Mani, Somnath

    2012-06-07T23:59:59.000Z

    A REDUCED BLADE - VORTEX INTERACTION ROTOR A Thesis by SOMNATH MANI . Submitted to the Offic of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1996 Major... Subject: Aerospace Engineering A REDUCED BLADE - VORTEX INTERACTION ROTOR A Thesis by SOMNATH MANI Submitted to Texas A@M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to style and content...

  18. Josephson vortex lattice melting in Bi-2212

    SciTech Connect (OSTI)

    Latyshev, Yu. I.; Pavlenko, V. N., E-mail: vit@cplire.ru; Orlov, A. P. [Russian Academy of Sciences, Institute of Radio Engineering and Electronics (Russian Federation)

    2007-07-15T23:59:59.000Z

    The B-T diagram of Josephson vortex lattice melting in Bi-2212 is analyzed (B is magnetic induction parallel to the layers, T is temperature). It is shown that the Josephson vortex lattice melting at B > B* = 0.6-0.7 T is associated with Berezinsky-Kosterlitz-Thouless transition in individual Bi-2212 superconducting layers and is a second-order phase transition.

  19. Reconnection of vortex filaments and Kolmogorov spectrum

    E-Print Network [OSTI]

    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.

  20. Differentiating swarming models by mimicking a frustrated anti-Ferromagnet

    E-Print Network [OSTI]

    Daniel J. G. Pearce; Matthew S. Turner

    2014-08-07T23:59:59.000Z

    Self propelled particle (SPP) models are often compared with animal swarms. However, the collective behaviour observed in experiments usually leaves considerable unconstrained freedom in the structure of these models. To tackle this degeneracy, and better distinguish between candidate models, we study swarms of SPPs circulating in channels (like spins) where we permit information to pass through windows between neighbouring channels. Co-alignment between particles then couples the channels (antiferromagnetically) so that they tend to counter-rotate. We study channels arranged to mimic a geometrically frustrated antiferromagnet and show how the effects of this frustration allow us to better distinguish between SPP models. Similar experiments could therefore improve our understanding of collective motion in animals. Finally we discuss how the spin analogy can be exploited to construct universal logic gates and therefore swarming systems that can function as Turing machines.

  1. Fluid Dynamics Research 33 (2003) 333356 Leapfrogging vortex rings: Hamiltonian structure, geometric

    E-Print Network [OSTI]

    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

  2. Polarization-selective vortex-core switching by tailored orthogonal Gaussian-pulse currents

    SciTech Connect (OSTI)

    Jung, H.; Choi, Y. -S.; Yoo, M. -W.; Im, M. -Y.; Kim, S. -K.

    2010-10-13T23:59:59.000Z

    We experimentally demonstrate low-power-consumption vortex-core switching in magnetic nanodisks using tailored rotating magnetic fields produced with orthogonal and unipolar Gaussian-pulse currents. The optimal width of the orthogonal pulses and their time delay are found, from analytical and micromagnetic numerical calculations, to be determined only by the angular eigenfrequency {omega}{sub D} for a given vortex-state disk of polarization p, such that {sigma}=1/{omega}{sub D} and ?{Delta}t={pi}/2 p/{omega}{sub D} . The estimated optimal pulse parameters are in good agreement with the experimental results. This work lays a foundation for energy-efficient information recording in vortex-core cross-point architecture.

  3. Low-amplitude magnetic vortex core reversal by non-linear interaction between azimuthal spin waves and the vortex gyromode

    SciTech Connect (OSTI)

    Sproll, Markus; Noske, Matthias; Kammerer, Matthias; Dieterle, Georg; Weigand, Markus; Stoll, Hermann; Schütz, Gisela [Max Planck Institute for Intelligent Systems (formerly MPI for Metals Research), Heisenbergstr. 3, 70569 Stuttgart (Germany)] [Max Planck Institute for Intelligent Systems (formerly MPI for Metals Research), Heisenbergstr. 3, 70569 Stuttgart (Germany); Bauer, Hans; Gangwar, Ajay; Woltersdorf, Georg; Back, Christian H. [Department of Physics, University of Regensburg, Universitätsstr. 31, 93040 Regensburg (Germany)] [Department of Physics, University of Regensburg, Universitätsstr. 31, 93040 Regensburg (Germany)

    2014-01-06T23:59:59.000Z

    We show, by experiments and micromagnetic simulations in vortex structures, that an active “dual frequency” excitation of both the sub-GHz vortex gyromode and multi-GHz spin waves considerably changes the frequency response of spin wave mediated vortex core reversal. Besides additional minima in the switching threshold, a significant broadband reduction of the switching amplitudes is observed, which can be explained by non-linear interaction between the vortex gyromode and the spin waves. We conclude that the well known frequency spectra of azimuthal spin waves in vortex structures are altered substantially, when the vortex gyromode is actively excited simultaneously.

  4. Homometallic and Heterometallic Antiferromagnetic Rings: Magnetic Properties Studied by Nuclear Magnetic Resonance

    SciTech Connect (OSTI)

    Casadei, Cecilia

    2012-05-09T23:59:59.000Z

    The aim of the present thesis is to investigate the local magnetic properties of homometallic Cr{sub 8} antiferromagnetic (AFM) ring and the changes occurring by replacing one Cr{sup 3+} ion with diamagnetic Cd{sup 2+} (Cr{sub 7}Cd) and with Ni{sup 2+} (Cr{sub 7}Ni). In the heterometallic ring a redistribution of the local magnetic moment is expected in the low temperature ground state. We have investigated those changes by both {sup 53}Cr-NMR and {sup 19}F-NMR. We have determined the order of magnitude of the transferred hyperfine coupling constant {sup 19}F - M{sup +} where M{sup +} = Cr{sup 3+}, Ni{sup 2+} in the different rings. This latter result gives useful information about the overlapping of the electronic wavefunctions involved in the coordinative bond.

  5. Fractal powers in Serrin's swirling vortex solutions

    E-Print Network [OSTI]

    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.

  6. Vortex reconnections between coreless vortices in binary condensates

    SciTech Connect (OSTI)

    Gautam, S. [Indian Institute of Science, Bangalore-560 012 (India); Suthar, K.; Angom, D. [Physical Research Laboratory, Ahmedabad-380 009 (India)

    2014-02-11T23:59:59.000Z

    Vortex reconnections plays an important role in the turbulent flows associated with the superfluids. To understand the dynamics, we examine the reconnections of vortex rings in the superfluids of dilute atomic gases confined in trapping potentials using Gross-Petaevskii equation. Further more we study the reconnection dynamics of coreless vortex rings, where one of the species can act as a tracer.

  7. PHYSICS OF FLUIDS 24, 125108 (2012) Quantum vortex reconnections

    E-Print Network [OSTI]

    Zuccher, Simone

    is continuous, not discrete, and parts of the initial vortical tubes can be left behind as vortex threads, whichPHYSICS OF FLUIDS 24, 125108 (2012) Quantum vortex reconnections S. Zuccher,1 M. Caliari,1 A. W that the minimum distance between vortices scales differently with time before and after the vortex reconnection

  8. Bluff Body Flow Simulation Using a Vortex Element Method

    SciTech Connect (OSTI)

    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.

  9. Vortex Jitter in Hover Swathi M. Mula

    E-Print Network [OSTI]

    Tinney, Charles E.

    78712, USA Abstract The trajectory of the tip vortex of a reduced-scale, 1 m diameter, four-bladed rotor condition of the rotor is at a blade loading of CT / = 0.0645 and a rotational speed of 1240RPM wake dominated by the tip vortices shed from the rotor blades. The complexity of the flow

  10. Quenching Processes in Flame-Vortex Interactions

    E-Print Network [OSTI]

    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

  11. Vortex dynamics in 4 Banavara N. Shashikanth

    E-Print Network [OSTI]

    Shashikanth, Banavara N.

    during the interaction of a pair of counter-rotating vortices Phys. Fluids 24, 014107 (2012) The onset of oblique vortex shedding behind a heated circular cylinder in laminar wake regime Phys. Fluids 24, 011701 fluids Phys. Fluids 23, 115106 (2011) Asymptotic properties of wall-induced chaotic mixing in point

  12. Jammed vortex matter Hajime Yoshino1

    E-Print Network [OSTI]

    Katsumoto, Shingo

    . Abstract: Irrationally frustrated Josephson junction array (JJA), namely JJA with irrational number density point. Figure 1: Josephson junction array (JJA) on a square lattice. The vertexes and bonds represent- not develop usual periodic vortex lattices. 1 Introduction Josephson junction array under mag- netic field

  13. Antiferromagnetic exchange bias of a ferromagnetic semiconductor by a ferromagnetic metal

    SciTech Connect (OSTI)

    Olejnik, K.; Wadley, P.; Haigh, J.; Edmonds, K. W.; Campion, R. P.; Rushforth, A. W.; Gallagher, B. L.; Foxon, C. T.; Jungwirth, T.; Wunderlich, J.; Dhesi, S. S.; Cavill, S.; van der Laan, G.; Arenholz, E.

    2009-11-05T23:59:59.000Z

    We demonstrate an exchange bias in (Ga,Mn)As induced by antiferromagnetic coupling to a thin overlayer of Fe. Bias fields of up to 240 Oe are observed. Using element-specific x-ray magnetic circular dichroism measurements, we distinguish an interface layer that is strongly pinned antiferromagnetically to the Fe. The interface layer remains polarized at room temperature.

  14. Neutron Scattering Studies of Vortex Matter in Type-II Superconductors

    SciTech Connect (OSTI)

    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.

  15. Spin-waves in Antiferromagnetically-Coupled Bimetallic Oxalates

    SciTech Connect (OSTI)

    Reis, Peter L [ORNL; Fishman, Randy Scott [ORNL

    2009-01-01T23:59:59.000Z

    Bimetallic oxalates are molecule-based magnets with transition-metal ions M(II) and M (III) arranged on an open honeycomb lattice. Performing a Holstein-Primakoff expansion, we obtain the spin-wave spectrum of antiferromagnetically-coupled bimetallic oxalates as a function of the crystal-field angular momentum L2 and L3 on the M(II) and M (III) sites. Our results are applied to the Fe(II)Mn(III), Ni(II)Mn(III) and V(II)V(III) bimetallic oxalates, where the spin-wave gap varies from 0 meV for quenched angular momentum to as high as 15 meV. The presence or absence of magnetic compensation appears to have no effect on the spin-wave gap.

  16. Deterministic Josephson Vortex Ratchet with a load

    E-Print Network [OSTI]

    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.

  17. Acceleration and vortex filaments in turbulence

    E-Print Network [OSTI]

    F. Toschi; L. Biferale; G. Boffetta; A. Celani; B. J. Devenish; A. Lanotte

    2005-01-23T23:59:59.000Z

    We report recent results from a high resolution numerical study of fluid particles transported by a fully developed turbulent flow. Single particle trajectories were followed for a time range spanning more than three decades, from less than a tenth of the Kolmogorov time-scale up to one large-eddy turnover time. We present some results concerning acceleration statistics and the statistics of trapping by vortex filaments.

  18. Effect of antiferromagnetic layer thickness on exchange bias, training effect, and magnetotransport properties in ferromagnetic/antiferromagnetic antidot arrays

    SciTech Connect (OSTI)

    Gong, W. J.; Liu, W., E-mail: wliu@imr.ac.cn; Feng, J. N.; Zhang, Z. D. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Kim, D. S.; Choi, C. J. [Functional Materials Division, Korea Institute of Materials Science, 531 Changwon- daero, Changwon 631-831 (Korea, Republic of)

    2014-04-07T23:59:59.000Z

    The effect of antiferromagnetic (AFM) layer on exchange bias (EB), training effect, and magnetotransport properties in ferromagnetic (FM) /AFM nanoscale antidot arrays and sheet films Ag(10?nm)/Co(8?nm)/NiO(t{sub NiO})/Ag(5?nm) at 10?K is studied. The AFM layer thickness dependence of the EB field shows a peak at t{sub NiO}?=?2?nm that is explained by using the random field model. The misalignment of magnetic moments in the three-dimensional antidot arrays causes smaller decrease of EB field compared with that in the sheet films for training effect. The anomalous magnetotransport properties, in particular positive magnetoresistance (MR) for antidot arrays but negative MR for sheet films are found. The training effect and magnetotransport properties are strongly affected by the three-dimensional spin-alignment effects in the antidot arrays.

  19. Liquid Vortex Shielding for Fusion Energy Applications

    SciTech Connect (OSTI)

    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.

  20. Optical vortex interaction and generation via nonlinear wave mixing

    SciTech Connect (OSTI)

    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.

  1. Laboratory Analysis of Vortex Dynamics For Shallow Tidal Inlets

    E-Print Network [OSTI]

    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...

  2. Magnetism of one-dimensional strongly repulsive spin-1 bosons with antiferromagnetic spin-exchange interaction

    SciTech Connect (OSTI)

    Lee, J. Y.; Guan, X. W. [Department of Theoretical Physics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 0200 (Australia); Batchelor, M. T. [Department of Theoretical Physics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 0200 (Australia); Mathematical Sciences Institute, Australian National University, Canberra, Australian Capital Territory 0200 (Australia); Lee, C. [Nonlinear Physics Centre and ARC Centre of Excellence for Quantum-Atom Optics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 0200 (Australia)

    2009-12-15T23:59:59.000Z

    We investigate magnetism and quantum phase transitions in a one-dimensional system of integrable spin-1 bosons with strongly repulsive density-density interaction and antiferromagnetic spin-exchange interaction via the thermodynamic Bethe ansatz method. At zero temperature, the system exhibits three quantum phases: (i) a singlet phase of boson pairs when the external magnetic field H is less than the lower critical field H{sub c1}; (ii) a ferromagnetic phase of atoms in the hyperfine state |F=1, m{sub F}=1> when the external magnetic field exceeds the upper critical field H{sub c2}; and (iii) a mixed phase of singlet pairs and unpaired atoms in the intermediate region H{sub c1}states to the dressed energy for the unpaired m{sub F}=1 bosons. However, such spin dynamics is suppressed by a sufficiently strong external field at low temperatures. Thus the singlet pairs and unpaired bosons may form a two-component Luttinger liquid in the strong coupling regime.

  3. Energy Separation And Lox Separation Studies In Vortex Tubes.

    E-Print Network [OSTI]

    Behera, Upendra

    2011-01-01T23:59:59.000Z

    ??Vortex Tube (VT) is a simple device having no moving mechanical parts, in which compressed gas at high pressure is injected through one or more… (more)

  4. Vortex motion rectification in Josephson junction arrays with a ratchet potential

    E-Print Network [OSTI]

    D. E. Shalom; H. Pastoriza

    2004-11-19T23:59:59.000Z

    By means of electrical transport measurements we have studied the rectified motion of vortices in ratchet potentials engineered on over-damped Josephson junction arrays. The rectified voltage as a function of the vortex density shows a maximum efficiency close a matching condition to the period of the ratchet potential indicating a collective vortex motion. Vortex current reversals where detected varying the driving force and vortex density revealing the influence of vortex-vortex interaction in the ratchet effect.

  5. An application of vortex cancellation to vortex generator techniques in low speed wind tunnels

    E-Print Network [OSTI]

    Mount, Glynn O., Jr

    2012-06-07T23:59:59.000Z

    'lugs/ft-sec Axial distance between sets of vortex generators root chord lengths /Y Vertical dimension of duct cross section Tube height/Y in. none ~St i t ()i ()2 (), ( )?q Measured at station g 1 Measured at Station 0 8 Upstream srl... to accomplish these objectives. The usefulness of many of them was limited because they were either too expensive, they could not be installed easily in existing wind tunnels, or their use involved excessive energy dissipation. Vortex Generators In 1/46 a...

  6. E-Print Network 3.0 - antarctica polar vortex Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    from MIPAS on Envisat make it hard to tell that the polar vortex... , produced by data assimilation, bringing the model and the observations together. The polar vortex... and...

  7. E-Print Network 3.0 - advanced vortex element Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    method of plasma Summary: with the new simple explanation of the energy separation in vortex tubes described here. Advanced numerical... vortex method of plasma insulation and...

  8. E-Print Network 3.0 - accelerated vortex ring Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    left behind... forces were derived from the vortex rings, assuming all propulsive energy to be compiled in the rings... , ending up in a separate vortex ... Source:...

  9. Evidence of exchange bias effect originating from the interaction between antiferromagnetic core and spin glass shell

    SciTech Connect (OSTI)

    Zhang, X. K., E-mail: zhangxianke77@163.com; Yuan, J. J.; Yu, H. J.; Zhu, X. R.; Xie, Y. M. [School of Physics and Electronics, Institute of Optoelectronic Materials and Technology, Gannan Normal University, Ganzhou 341000 (China); Tang, S. L.; Xu, L. Q. [Nanjing National Laboratory of Microstructures, College of Physics, Nanjing University, Nanjing 210093 (China)

    2014-07-14T23:59:59.000Z

    Spin glass behavior and exchange bias effect have been observed in antiferromagnetic SrMn{sub 3}O{sub 6?x} nanoribbons synthesized via a self-sacrificing template process. The magnetic field dependence of thermoremanent magnetization and isothermal remanent magnetization shows that the sample is good correspondence to spin glass and diluted antiferromagnetic system for the applied field H??2?T, respectively. By detailed analysis of training effect using Binek's model, we argue that the observed exchange bias effect in SrMn{sub 3}O{sub 6?x} nanoribbons arises entirely from an interface exchange coupling between the antiferromagnetic core and spin glass shell. The present study is useful for understanding the nature of shell layer and the origin of exchange bias effect in other antiferromagnetic nanosystems as well.

  10. Vortex Lattice Modelling of Winglets on Wind Turbine Blades

    E-Print Network [OSTI]

    Vortex Lattice Modelling of Winglets on Wind Turbine Blades Mads Døssing Risø-R-1621(EN) Risø 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

  11. Finned Tube With Vortex Generators For A Heat Exchanger.

    DOE Patents [OSTI]

    Sohal, Manohar S. (Idaho Falls, ID); O'Brien, James E. (Idaho Falls, ID)

    2005-12-20T23:59:59.000Z

    A system for and method of manufacturing a finned tube for a heat exchanger is disclosed herein. A continuous fin strip is provided with at one pair of vortex generators. A tube is rotated and linearly displaced while the continuous fin strip with vortex generators is spirally wrapped around the tube.

  12. Metallic Interface Emerging at Magnetic Domain Wall of Antiferromagnetic Insulator---Fate of Extinct Weyl Electrons

    E-Print Network [OSTI]

    Youhei Yamaji; Masatoshi Imada

    2014-03-12T23:59:59.000Z

    Topological insulators, in contrast to ordinary semiconductors, accompany protected metallic surfaces described by Dirac-type fermions. Here, we theoretically show another emergent two-dimensional metal embedded in the bulk insulator is realized at a magnetic domain wall. The domain wall has long been studied as ingredients of both old-fashioned and leading-edge spintronics. The domain wall here, as an interface of seemingly trivial antiferromagnetic insulators, emergently realizes a functional interface preserved by zero modes with robust two-dimensional Fermi surfaces, where pyrochlore iridium oxides proposed to host condensed-matter realization of Weyl fermions offer such examples at low temperatures. The existence of ingap states pinned at domain walls, theoretically resembling spin/charge solitons in polyacetylene, and protected as the edge of hidden one-dimensional weak Chern insulators characterized by a zero-dimensional class A topological invariant, solves experimental puzzles observed in R2Ir2O7 with rare earth elements R. The domain wall realizes a novel quantum confinement of electrons and embosses a net uniform magnetization, which enables magnetic control of electronic interface transports beyond semiconductor paradigm.

  13. Vortex and Droplet Engineering in Holographic Superconductors

    E-Print Network [OSTI]

    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.

  14. Dynamics of Magnetized Vortex Tubes in the Solar Chromosphere

    E-Print Network [OSTI]

    Kitiashvili, I N; Mansour, N N; Wray, A A

    2012-01-01T23:59:59.000Z

    We use 3D radiative MHD simulations to investigate the formation and dynamics of small-scale (less than 0.5 Mm in diameter) vortex tubes spontaneously generated by turbulent convection in quiet-Sun regions with initially weak mean magnetic fields. The results show that the vortex tubes penetrate into the chromosphere and substantially affect the structure and dynamics of the solar atmosphere. The vortex tubes are mostly concentrated in intergranular lanes and are characterized by strong (near sonic) downflows and swirling motions that capture and twist magnetic field lines, forming magnetic flux tubes that expand with height and which attain magnetic field strengths ranging from 200 G in the chromosphere to more than 1 kG in the photosphere. We investigate in detail the physical properties of these vortex tubes, including thermodynamic properties, flow dynamics, and kinetic and current helicities, and conclude that magnetized vortex tubes provide an important path for energy and momentum transfer from the con...

  15. Non-Riemannian geometry of vortex acoustics

    SciTech Connect (OSTI)

    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.

  16. Potential Flow Model of a Vortex Street Near a Fish-like Body

    E-Print Network [OSTI]

    Anlage, Steven

    Potential Flow Model of a Vortex Street Near a Fish-like Body Joshua Brulé, University of Maryland to inviscid, irrotational solutions of Navier-Stokes · Vortex potential: "A model of the lateral line of fish for vortex sensing." Ren Z, Mohseni K. 2012 #12;Vortex near a (circular) fish · (Insert your own spherical

  17. Vortex-vacancy interactions in two-dimensional easy-plane magnets G. M. Wysin

    E-Print Network [OSTI]

    Wysin, Gary

    Vortex-vacancy interactions in two-dimensional easy-plane magnets G. M. Wysin Department of Physics of a magnetic vacancy site on a nearby magnetic vortex are analyzed on square, hexagonal and triangular lattices. When the vortex is centered on a vacancy, the critical anisotropies where the stable vortex structure

  18. Irreversible flow of vortex matter: Polycrystal and amorphous phases Paolo Moretti and M.-Carmen Miguel

    E-Print Network [OSTI]

    Miguel-Lopez, Carmen

    systems exhibiting this phenomenol- ogy, flux line vortex lattices in type II superconductors rep- resent

  19. X-ray imaging of dispersive charge modes in a doped Mott insulator near the antiferromagnetic/superconductor transition

    SciTech Connect (OSTI)

    Li, Y.W.; Qian, D.; Wray, L.; Hsieh, D.; Xia, Y.; Kaga, Y.; Sasagawa, T.; Takagi, H.; Markiewicz, R.S.; Bansil, A.; Eisaki, H.; Uchida, S.; Hasan, M.Z. (U of Tokyo); (AIST); (Princeton); (NEU)

    2009-01-12T23:59:59.000Z

    Momentum-resolved inelastic resonant x-ray scattering is used to map the doping evolution of bulk electronic modes in the doped Mott insulator class Nd{sub 2-x}Ce{sub x}CuO{sub 4}. As the doping induced antiferromagnet/superconductor (AFM/SC) transition is approached, we observe an anisotropic redistribution of the spectral weight of collective excitations over a large energy scale along the {Gamma} {yields} ({pi},{pi}) direction, whereas the modes exhibit broadening (-1 eV) with relatively little softening along {Gamma} {yields} ({pi},0) with respect to the parent Mott state (x=0). Our study reveals a closing of the charge gap in the vicinity of the zone center even though the mode softening and spectral redistribution involve an unusually large energy scale over the full Brillouin zone. The collective behavior of modes in the vicinity of the AFM/SC critical transition is demonstrated.

  20. Interstitials, Vacancies and Dislocations in Flux-Line Lattices: A Theory of Vortex Crystals, Supersolids and Liquids

    E-Print Network [OSTI]

    M. Cristina Marchetti; Leo Radzihovsky

    1999-07-01T23:59:59.000Z

    We study a three dimensional Abrikosov vortex lattice in the presence of an equilibrium concentration of vacancy, interstitial and dislocation loops. Vacancies and interstitials renormalize the long-wavelength bulk and tilt elastic moduli. Dislocation loops lead to the vanishing of the long-wavelength shear modulus. The coupling to vacancies and interstitials - which are always present in the liquid state - allows dislocations to relax stresses by climbing out of their glide plane. Surprisingly, this mechanism does not yield any further independent renormalization of the tilt and compressional moduli at long wavelengths. The long wavelength properties of the resulting state are formally identical to that of the ``flux-line hexatic'' that is a candidate ``normal'' hexatically ordered vortex liquid state.

  1. Vortex configurations of bosons in an optical lattice

    SciTech Connect (OSTI)

    Wu Congjun; Zhang Shoucheng [Department of Physics, McCullough Building, Stanford University, Stanford, California 94305-4045 (United States); Chen Handong [Department of Applied Physics, McCullough Building, Stanford University, Stanford, California 94305-4045 (United States); Hu Jiangpiang [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)

    2004-04-01T23:59:59.000Z

    The single-vortex problem in a strongly correlated bosonic system is investigated self-consistently within the mean-field theory of the Bose-Hubbard model. Near the superfluid-Mott-insulator transition, the vortex core has a tendency toward the Mott-insulating phase, with the core particle density approaching the nearest commensurate value. If the nearest-neighbor repulsion exists, the charge-density wave order may develop locally in the core. The evolution of the vortex configuration from the strong- to weak-coupling regions is studied. This phenomenon can be observed in systems of rotating ultracold atoms in optical lattices and Josephson-junction arrays.

  2. Sound Wave in Vortex with Sink

    E-Print Network [OSTI]

    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 $A$.

  3. The controlled indirect coupling between spatially-separated qubits in antiferromagnet-based NMR quantum registers

    E-Print Network [OSTI]

    A. A. Kokin

    2004-10-31T23:59:59.000Z

    It is considered the indirect inter-qubit coupling in 1D chain of atoms with nuclear spins 1/2, which plays role of qubits in the quantum register. This chain of the atoms is placed by regular way in easy-axis 3D antiferromagnetic thin plate substrate, which is cleaned from the other nuclear spin containing isotopes. It is shown that the range of indirect inter-spin coupling may run to a great number of lattice constants both near critical point of quantum phase transition in antiferromagnet of spin-flop type (control parameter is external magnetic field) and/or near homogeneous antiferromagnetic resonance (control parameter is microwave frequency).

  4. A study on passive methods of vortex induced vibrations suppression

    E-Print Network [OSTI]

    Galvao, Richardo A

    2008-01-01T23:59:59.000Z

    A number of engineering systems, including those found in offshore operations, are often affected by vortex-induced vibrations (VIV). This phenomenon is caused by the interaction between a structure and shed vortices which ...

  5. Drag amplification and fatigue damage in vortex-induced vibrations

    E-Print Network [OSTI]

    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 ...

  6. Vortex-induced vibration of slender structures in unsteady flow

    E-Print Network [OSTI]

    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 ...

  7. Vortex hair on AdS black holes

    E-Print Network [OSTI]

    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.

  8. Axionic Antiferromagnetic Insulator Phase in a Correlated and Spin-Orbit Coupled System

    E-Print Network [OSTI]

    Akihiko Sekine; Kentaro Nomura

    2014-09-24T23:59:59.000Z

    We study theoretically a three-dimensional correlated and spin-orbit coupled system, the half-filled extended Fu-Kane-Mele-Hubbard model on a diamond lattice, focusing on the topological magnetoelectric response of the antiferromagnetic insulator phase. In the antiferromagnetic insulator phase, the Dirac-like low-energy effective Hamiltonian is obtained. Then the theta term, which results in the magnetoelectric response, is derived as a consequence of the chiral anomaly. The realization of the dynamical axion field in our model is discussed. The relation with a symmetry broken phase induced by interactions in lattice quantum chromodynamics is also discussed.

  9. Topological superconductivity, topological confinement, and the vortex quantum Hall effect

    SciTech Connect (OSTI)

    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.

  10. PHYSICAL REVIEW B 87, 085107 (2013) Heisenberg antiferromagnet on Cayley trees: Low-energy spectrum and even/odd site imbalance

    E-Print Network [OSTI]

    Henley, Christopher L.

    PHYSICAL REVIEW B 87, 085107 (2013) Heisenberg antiferromagnet on Cayley trees: Low-energy spectrum of local sublattice imbalance in low-energy spectra of s = 1 2 quantum antiferromagnets, we study the s = 1 2 quantum nearest neighbor Heisenberg antiferromagnet on the coordination 3 Cayley tree. We perform

  11. antiferromagnetic fermi liquid: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    cuprates differ from conventional superconductors in three crucial aspects: the superconducting state descends from a strongly correlated Mott-Hubbard insulator, the order...

  12. Semimetallic antiferromagnetism in the half-Heusler compound CuMnSb Ruben Weht,2

    E-Print Network [OSTI]

    Pickett, Warren

    CuMnSb, the first antiferromagnet AFM in the Mn-based class of Heuslers and half-Heuslers that contains several conventional and half metallic ferromagnets, shows a peculiar stability of its magnetic order in high magnetic fields. Density functional based studies reveal an unusual nature of its unstable

  13. Structural distortions in the spin-gap regime of the quantum antiferromagnet SrCu{sub 2}(BO{sub 3}){sub 2}

    SciTech Connect (OSTI)

    Vecchini, C., E-mail: c.vecchini@rl.ac.u [Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Vassilika Vouton, 711 10 Heraklion, Crete (Greece); ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Adamopoulos, O. [Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Vassilika Vouton, 711 10 Heraklion, Crete (Greece); Department of Chemistry, University of Crete, Voutes, 710 03 Heraklion (Greece); Chapon, L.C. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Lappas, A., E-mail: lappas@iesl.forth.g [Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Vassilika Vouton, 711 10 Heraklion, Crete (Greece); Kageyama, H. [Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Ueda, Y. [Institute of Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Zorko, A. [Institute Jozef Stefan, Jamova 39, 1000 Ljubljana (Slovenia)

    2009-12-15T23:59:59.000Z

    We report the first crystallographic study within the low-temperature (<40 K) spin-gap region of the two-dimensional frustrated antiferromagnet SrCu{sub 2}(BO{sub 3}){sub 2}. The crystal system does not deviate from the tetragonal I-42m space group symmetry. However, our high-resolution neutron powder diffraction measurements uncover subtle structural modifications below 34 K, concomitant to the formation of the dimer singlet ground state. Intimate spin-lattice coupling leads to negative thermal expansion of the tetragonal structure, which reflects into particular local lattice adjustments. The extracted structural parameters suggest the reduction of the buckling found in the copper-borate planes and the strengthening of the leading, in-plane intra-dimer superexchange interaction. The observed contraction along the c-axis, associated with the inter-dimer exchange in adjacent layers, indicates the involvement of weaker three-dimensional interactions in the magnetic properties. The rules posed by the crystal symmetry do not preclude Dzyaloshinsky-Moriya interactions, which therefore remain as an important source of spin anisotropy necessary to rationalise the ground state behaviour. - Abstract: We report the first crystallographic study within the low-temperature spin-gap region of the two-dimensional frustrated antiferromagnet SrCu{sub 2}(BO{sub 3}){sub 2}. Subtle spin-lattice coupling was unveiled in the low-temperature region. Display Omitted

  14. Ultra-Low NOx Advanced Vortex Combustor

    SciTech Connect (OSTI)

    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.

  15. ULTRA-LOW NOX ADVANCED VORTEX COMBUSTOR

    SciTech Connect (OSTI)

    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.

  16. Relativistic generation of vortex and magnetic field

    SciTech Connect (OSTI)

    Mahajan, S. M. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States); Yoshida, Z. [Graduate School of Frontier Sciences, University of Tokyo, Chiba 277-8561 (Japan)

    2011-05-15T23:59:59.000Z

    The implications of the recently demonstrated relativistic mechanism for generating generalized vorticity in purely ideal dynamics [Mahajan and Yoshida, Phys. Rev. Lett. 105, 095005 (2010)] are worked out. The said mechanism has its origin in the space-time distortion caused by the demands of special relativity; these distortions break the topological constraint (conservation of generalized helicity) forbidding the emergence of magnetic field (a generalized vorticity) in an ideal nonrelativistic dynamics. After delineating the steps in the ''evolution'' of vortex dynamics, as the physical system goes from a nonrelativistic to a relativistically fast and hot plasma, a simple theory is developed to disentangle the two distinct components comprising the generalized vorticity--the magnetic field and the thermal-kinetic vorticity. The ''strength'' of the new universal mechanism is, then, estimated for a few representative cases; in particular, the level of seed fields, created in the cosmic setting of the early hot universe filled with relativistic particle-antiparticle pairs (up to the end of the electron-positron era), are computed. Possible applications of the mechanism in intense laser produced plasmas are also explored. It is suggested that highly relativistic laser plasma could provide a laboratory for testing the essence of the relativistic drive.

  17. A PARAMETER STUDY FOR BAROCLINIC VORTEX AMPLIFICATION

    SciTech Connect (OSTI)

    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.

  18. Wave–vortex interactions in the nonlinear Schrödinger equation

    SciTech Connect (OSTI)

    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.

  19. UBIQUITOUS SOLAR ERUPTIONS DRIVEN BY MAGNETIZED VORTEX TUBES

    SciTech Connect (OSTI)

    Kitiashvili, I. N.; Kosovichev, A. G. [Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States); Lele, S. K.; Mansour, N. N.; Wray, A. A., E-mail: irinasun@stanford.edu [Center for Turbulence Research, Stanford University, Stanford, CA 94305 (United States)

    2013-06-10T23:59:59.000Z

    The solar surface is covered by high-speed jets transporting mass and energy into the solar corona and feeding the solar wind. The most prominent of these jets have been known as spicules. However, the mechanism initiating these eruption events is still unknown. Using realistic numerical simulations we find that small-scale eruptions are produced by ubiquitous magnetized vortex tubes generated by the Sun's turbulent convection in subsurface layers. The swirling vortex tubes (resembling tornadoes) penetrate into the solar atmosphere, capture and stretch background magnetic field, and push the surrounding material up, generating shocks. Our simulations reveal complicated high-speed flow patterns and thermodynamic and magnetic structure in the erupting vortex tubes. The main new results are: (1) the eruptions are initiated in the subsurface layers and are driven by high-pressure gradients in the subphotosphere and photosphere and by the Lorentz force in the higher atmosphere layers; (2) the fluctuations in the vortex tubes penetrating into the chromosphere are quasi-periodic with a characteristic period of 2-5 minutes; and (3) the eruptions are highly non-uniform: the flows are predominantly downward in the vortex tube cores and upward in their surroundings; the plasma density and temperature vary significantly across the eruptions.

  20. Experimental Investigations of Vortex Induced Vibration of A Flat Plate in Pitch Oscillation

    E-Print Network [OSTI]

    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...

  1. Vortex in a relativistic perfect isentropic fluid and Nambu Goto dynamics

    E-Print Network [OSTI]

    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

  2. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Wednesday, 25 November 2009 00:00 Magnetic...

  3. Generation and Propagation of Inertia Gravity Waves from Vortex Dipoles and Jets Shuguang Wang

    E-Print Network [OSTI]

    Generation and Propagation of Inertia Gravity Waves from Vortex Dipoles and Jets Shuguang Wang generation and propagation from jets within idealized vortex dipoles using a nonhydrostatic mesoscale model, moist convection, fronts, upper level jets, geostrophic adjustment and spontaneous generation (Fritts

  4. Low Head, Vortex Induced Vibrations River Energy Converter

    SciTech Connect (OSTI)

    Bernitsas, Michael B.; Dritz, Tad

    2006-06-30T23:59:59.000Z

    Vortex Induced Vibrations Aquatic Clean Energy (VIVACE) is a novel, demonstrated approach to extracting energy from water currents. This invention is based on a phenomenon called Vortex Induced Vibrations (VIV), which was first observed by Leonardo da Vinci in 1504AD. He called it ‘Aeolian Tones.’ For decades, engineers have attempted to prevent this type of vibration from damaging structures, such as offshore platforms, nuclear fuel rods, cables, buildings, and bridges. The underlying concept of the VIVACE Converter is the following: Strengthen rather than spoil vortex shedding; enhance rather than suppress VIV; harness rather than mitigate VIV energy. By maximizing and utilizing this unique phenomenon, VIVACE takes this “problem” and successfully transforms it into a valuable resource for mankind.

  5. Ubiquitous Solar Eruptions Driven by Magnetized Vortex Tubes

    E-Print Network [OSTI]

    Kitiashvili, I N; Lele, S K; Mansour, N N; Wray, A A

    2013-01-01T23:59:59.000Z

    The solar surface is covered by high-speed jets transporting mass and energy into the solar corona and feeding the solar wind. The most prominent of these jets have been known as spicules. However, the mechanism initiating these eruptions events is still unknown. Using realistic numerical simulations we find that small-scale eruptions are produced by ubiquitous magnetized vortex tubes generated by the Sun's turbulent convection in subsurface layers. The swirling vortex tubes (resembling tornadoes) penetrate into the solar atmosphere, capture and stretch background magnetic field, and push surrounding material up, generating quasiperiodic shocks. Our simulations reveal a complicated high-speed flow patterns, and thermodynamic and magnetic structure in the erupting vortex tubes. We found that the eruptions are initiated in the subsurface layers and are driven by the high-pressure gradients in the subphotosphere and photosphere, and by the Lorentz force in the higher atmosphere layers.

  6. The effect of surface tension on the Moore singularity of vortex sheet dynamics

    E-Print Network [OSTI]

    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

  7. Traveling Waves from the Arclength Parameterization: Vortex Sheets with Surface Tension

    E-Print Network [OSTI]

    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

  8. Vortex Interactions and Barotropic Aspects of Concentric Eyewall Formation HUNG-CHI KUO

    E-Print Network [OSTI]

    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

  9. CALTECH ASCI TECHNICAL REPORT 129 On Velocity Structure Functions and the Spherical Vortex Model for

    E-Print Network [OSTI]

    Barr, Al

    the stretched-spiral vortex has been suc- cessfully applied to the calculation of the energy spectrum,6 and some for larger scales is perhaps questionable. Most quantitative vortex-based models have utilized tube and sheetCALTECH ASCI TECHNICAL REPORT 129 On Velocity Structure Functions and the Spherical Vortex Model

  10. Vortex reconnections in atomic condensates at finite temperature A. J. Allen1

    E-Print Network [OSTI]

    Zuccher, Simone

    , reconnections of stream lines, vortex lines and magnetic flux tubes change the topology of the flowVortex reconnections in atomic condensates at finite temperature A. J. Allen1 , S. Zuccher2 , M (Dated: May 28, 2014) The study of vortex reconnections is an essential ingredient of understanding

  11. Crystal structure dependence of antiferromagnetic coupling in Fe/Si multilayers

    SciTech Connect (OSTI)

    Michel, R.P.; Chaiken, A.; Wall, M.A.

    1995-04-01T23:59:59.000Z

    Recent reports of temperature dependent antiferromagnetic coupling in Fe/Si multilayers have motivated the generalization of models describing magnetic coupling in metal/metal multilayers to metal/insulator and metal/semiconductor layered systems. Interesting dependence of the magnetic properties on layer thickness and temperature are predicted. We report measurements that show the antiferromagnetic (AF) coupling observed in Fe/Si multilayers is strongly dependent on the crystalline coherence of the silicide interlayer. Electron diffraction images show the silicide interlayer has a CsCl structure. It is not clear at this time whether the interlayer is a poor metallic conductor or a semiconductor so the relevance of generalized coupling theories is unclear.

  12. Magnetic Interactions in the Geometrically Frustrated Triangular Lattice Antiferromagnet CuFeO2

    SciTech Connect (OSTI)

    Ye, Feng [ORNL; Fernandez-Baca, Jaime A [ORNL; Fishman, Randy Scott [ORNL; Ren, Y. [Argonne National Laboratory (ANL); Qiu, Y. [National Institute of Standards and Technology (NIST); Kimura, T. [Osaka University

    2007-01-01T23:59:59.000Z

    The spin-wave excitations of the geometrically frustrated triangular lattice antiferromagnet CuFeO2 have been measured using high resolution inelastic neutron scattering. Antiferromagnetic interactions up to third nearest neighbors in the ab plane (J1, J2, J3, with J2=J1 0:44 and J3=J1 0:57), as well as out-of-plane coupling (Jz, with Jz=J1 0:29) are required to describe the spin-wave dispersion relations, indicating a three-dimensional character of the magnetic interactions. Two energy dips in the spin-wave dispersion occur at the incommensurate wave vectors associated with multiferroic phase and can be interpreted as dynamic precursors to the magnetoelectric behavior in this system.

  13. Magnetic Interaction in the Geometrically Frustrated Triangular LatticeAntiferromagnet CuFeO2

    SciTech Connect (OSTI)

    Ye, Feng [ORNL; Fernandez-Baca, Jaime A [ORNL; Fishman, Randy Scott [ORNL; Ren, Y. [Argonne National Laboratory (ANL); Kang, H. J. [National Institute of Standards and Technology (NIST); Qiu, Y. [National Institute of Standards and Technology (NIST); Kimura, T. [Los Alamos National Laboratory (LANL)

    2007-01-01T23:59:59.000Z

    The spin wave excitations of the geometrically frustrated triangular lattice antiferromagnet (TLA) CuFeO2 have been measured using high resolution inelastic neutron scattering. Antiferromagnetic interactions up to third nearest neighbors in the ab plane (J1, J2, J3, with J2=J1 0:44 and J3=J1 0:57), as well as out-of-plane coupling (Jz, with Jz=J1 0:29) are required to describe the spin wave dispersion relations, indicating a three dimensional character of the magnetic interactions. Two energy deeps in the spin wave dispersion occur at the incommensurate wavevectors associated with multiferroic phase, and can be interpreted as dynamic precursors to the magnetoelectric behavior in this system.

  14. Strain-modulated antiferromagnetic spin orientation and exchange coupling in Fe/CoO(001)

    SciTech Connect (OSTI)

    Zhu, J.; Li, Q.; Li, J. X.; Ding, Z.; Wu, Y. Z., E-mail: wuyizheng@fudan.edu.cn [Department of Physics, State Key Laboratory of Surface Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433 (China); Hua, C. Y.; Huang, M. J.; Lin, H.-J. [National Synchrotron Radiation Research Center and Department of Physics, National Tsing-Hua University, Hsinchu 30077, Taiwan (China); Hu, Z. [Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Str. 40, 01187 Dresden (Germany); Won, C. [Department of Physics, Kyung Hee University, Seoul 130-701 (Korea, Republic of)

    2014-05-21T23:59:59.000Z

    The effect of CoO spin orientation on exchange coupling was investigated in single-crystalline Fe/CoO/MnO/MgO(001) systems. An antiferromagnetic CoO spin reorientation transition from the in-plane direction to the out-of-plane direction was found to be associated with the in-plane strain transition in CoO film from compression to expansion. The induced uniaxial anisotropies by exchange coupling at the Fe/CoO interface are significantly stronger for the in-plane CoO spin orientation than for the out-of-plane CoO spin orientation. Our study provides a way to modify the exchange coupling in the ferromagnetic (FM)/antiferromagnetic (AFM) bilayer by modulating the strain in the AFM film.

  15. Investigation of Vortex Structures in Gas-Discharge Nonneutral Electron Plasma: II. Vortex Formation, Evolution and Dynamics

    E-Print Network [OSTI]

    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.

  16. LINEAR DISPERSIVE DECAY ESTIMATES FOR VORTEX SHEETS WITH SURFACE TENSION

    E-Print Network [OSTI]

    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

  17. High-Resolution Simulations of Parallel BladeVortex Interactions

    E-Print Network [OSTI]

    Alonso, Juan J.

    = perturbation pressure coefficient, p ps= 1 2 1U2 1 c = rotor blade chord p = instantaneous airfoil surface­vortex interaction computations Introduction A MAJOR source of rotorcraft noise is generated by the rotor blades on the rotor blades. BVI noise is especially important because it is known to propagate out

  18. Creation and pinning of vortex-antivortex pairs

    E-Print Network [OSTI]

    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...

  19. General-Relativistic Curvature of Pulsar Vortex Structure

    E-Print Network [OSTI]

    A. A. Shatskiy

    2001-04-23T23:59:59.000Z

    The motion of a neutron superfluid condensate in a pulsar is studied. Several theorems of general-relativistic hydrodynamics are proved for a superfluid. The average density distribution of vortex lines in pulsars and their general-relativistic curvature are derived.

  20. Vortex Shedding on Hydrofoils Its dark and lonely down there...

    E-Print Network [OSTI]

    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

  1. WAVE-VORTEX INTERACTIONS IN THE ATMOSPHERE, AND CLIMATE

    E-Print Network [OSTI]

    Vellekoop, Michel

    parcel dynamics, linear modes, balan- ced models, gravity waves, weather and climate prediction Introduction Numerical weather and climate prediction is complicated because only the flow scales larger thanWAVE-VORTEX INTERACTIONS IN THE ATMOSPHERE, AND CLIMATE PREDICTION Onno Bokhove Numerical Analysis

  2. Vortex phase-jitter in acoustically excited bluff body flames

    E-Print Network [OSTI]

    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

  3. Modified Black Hole with Polar Jet and Vortex

    E-Print Network [OSTI]

    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.

  4. -STABILITY AND VORTEX MOTION IN TYPE II SUPERCONDUCTORS

    E-Print Network [OSTI]

    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

  5. Inhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates

    E-Print Network [OSTI]

    Paris-Sud XI, Université 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

  6. Inhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates

    E-Print Network [OSTI]

    Paris-Sud XI, Université 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

  7. Structural and magnetic properties of the Kagome antiferromagnet YbBaCo{sub 4}O{sub 7}

    SciTech Connect (OSTI)

    Huq, A. [Intense Pulsed Neutron Source, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 (United States); Mitchell, J.F. [Materials Science Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 (United States)]. E-mail: mitchell@anl.gov; Zheng, H. [Materials Science Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 (United States); Chapon, L.C. [ISIS Facility, Rutherford Appleton Laboratory-CCLRC, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Radaelli, P.G. [ISIS Facility, Rutherford Appleton Laboratory-CCLRC, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Knight, K.S. [ISIS Facility, Rutherford Appleton Laboratory-CCLRC, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Stephens, P.W. [Department of Physics and Astronomy, SUNY Stonybrook, NY 11794 (United States)

    2006-04-15T23:59:59.000Z

    The mixed-valent compound YbBaCo{sub 4}O{sub 7} is built up of Kagome sheets of CoO{sub 4} tetrahedra, linked in the third dimension by a triangular layer of CoO{sub 4} tetrahedra in an analogous fashion to that found in the known geometrically frustrated magnets such as pyrochlores and SrCr{sub 9} {sub x} Ga{sub 12-9} {sub x} O{sub 19} (SCGO). We have undertaken a study of the structural and magnetic properties of this compound using combined high-resolution powder neutron and synchrotron X-ray diffraction. YbBaCo{sub 4}O{sub 7} undergoes a first-order trigonal{sup {yields}}orthorhombic phase transition at 175 K. We show that this transition occurs as a response to a markedly underbonded Ba{sup 2+} site in the high-temperature phase and does not appear to involve charge ordering of Co{sup 2+}/Co{sup 3+} ions in the tetrahedra. The symmetry lowering relieves the geometric frustration of the structure, and a long-range-ordered 3-D antiferromagnetic state develops below 80 K.

  8. Vortex-line condensation in three dimensions: A physical mechanism for bosonic topological insulators

    E-Print Network [OSTI]

    Peng Ye; Zheng-Cheng Gu

    2014-11-20T23:59:59.000Z

    Bosonic topological insulators (BTI) in three spatial dimensions are symmetry protected topological (SPT) phases with U(1)$\\rtimes$Z$^T_2$ symmetry, where U(1) is boson particle number conservation, and Z$^T_2$ is time-reversal symmetry with $\\mathcal{T}^2=1$. BTI were first proposed based on the group cohomology theory which suggests two distinct root states, each carrying a $\\mathbb{Z}_2$ index. Soon after, surface anomalous topological orders were proposed to identify different root states of BTI, leading to a new BTI root state beyond the group cohomology classification. Nevertheless, it is still unclear what is the universal physical mechanism for BTI phases and what kinds of microscopic Hamiltonians can realize them. In this paper, we answer the first question by proposing a universal physical mechanism via vortex-line condensation in a superfluid, which can potentially be realized in realistic systems, e.g., helium-4 or cold atoms in optical lattices. Using such a simple physical picture, we find three root phases, of which two of them are classified by group cohomology theory while the other is beyond group cohomology classification. The physical picture also leads to a "natural" bulk dynamic topological quantum field theory (TQFT) description for BTI phases and gives rise to a possible physical pathway towards experimental realizations. Finally, we generalize the vortex-line condensation picture to other symmetries and find that in three dimensions, even for a unitary Z$_2$ symmetry, there could be a nontrivial Z$_2$ SPT phase beyond the group cohomology classification.

  9. Low-temperature thermal conductivity of antiferromagnetic S?=?1/2 chain material CuCl{sub 2}·2((CH{sub 3}){sub 2}SO)

    SciTech Connect (OSTI)

    Ke, W. P.; Zhang, F. B.; Zhao, Z. Y.; Fan, C.; Sun, X. F., E-mail: xfsun@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Shi, J. [Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhao, X., E-mail: xiazhao@ustc.edu.cn [School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-05-07T23:59:59.000Z

    We study the heat transport of S?=?1/2 chain compound CuCl{sub 2}·2((CH{sub 3}){sub 2}SO) along the b axis (vertical to the chain direction) at very low temperatures. The zero-field thermal conductivity (?) shows a distinct kink at about 0.9?K, which is related to the long-range antiferromagnetic (AF) transition. With applying magnetic field along the c axis, ?(H) curves also show distinct changes at the phase boundaries between the AF and the high-field disordered states. These results indicate a strong spin-phonon interaction and the magnetic excitations play a role in the b-axis heat transport as phonon scatterers.

  10. Vortex arrays and meso-scale turbulence of self-propelled particles

    E-Print Network [OSTI]

    Robert Grossmann; Pawel Romanczuk; Markus Bär; Lutz Schimansky-Geier

    2014-05-30T23:59:59.000Z

    Inspired by the Turing mechanism for pattern formation, we propose a simple self-propelled particle model with short-ranged alignment and anti-alignment at larger distances. It is able to produce orientationally ordered states, periodic vortex patterns as well as meso-scale turbulence. The latter phase resembles observations in dense bacterial suspensions. The model allows a systematic derivation and analysis of a kinetic theory as well as hydrodynamic equations for density and momentum fields. A phase diagram with regions of such pattern formation as well as spatially homogeneous orientational order and disorder is obtained from a linear stability analysis of these continuum equations. Microscopic Langevin simulations of the self-propelled particle system are in agreement with these findings.

  11. Photo- and thermal-induced antiferromagnetic interlayer coupling in Fe/(Fe-Si) superlattices

    SciTech Connect (OSTI)

    Mattson, J.E.; Fullerton, E.E.; Kumar, S.; Lee, S.R.; Sowers, C.H.; Grimsditch, M.; Bader, S.D. [Argonne National Lab., IL (United States); Parker, F.T. [California Univ., San Diego, La Jolla, CA (United States). Center for Magnetic Recording Research

    1993-08-01T23:59:59.000Z

    We have grown via sputtering, Fe - iron silicide superlattices that exhibit novel thermal and photomagnetic effects. For {approximately}15 {Angstrom} nominal thickness of the silicide layer the superlattices are antiferromagnetically (AF) coupled at room temperature. Upon cooling below 100K, they gradually revert to ferromagnetic alignment, but the AF coupling is restored at low temperature by exposure to visible light off sufficient intensity (> 10 mW/mm{sup 2}). These effects are due to charge carriers in the silicide spacer layer which, when thermally or photo-generated, are capable of communicating spin information between the Fe layers.

  12. Dynamic selective switching in antiferromagnetically-coupled bilayers close to the spin reorientation transition

    E-Print Network [OSTI]

    Fern ández-Pacheco, A.; Ummelen, F. C.; Mansell, R.; Petit, D.; Lee, J. H.; Swagten, H. J. M.; Cowburn, R. P.

    2014-09-05T23:59:59.000Z

    /Pt–Co/Ni–Co/Pt multilayers studied via soft x-ray techniques Appl. Phys. Lett. 98, 172503 (2011); 10.1063/1.3583454 Magnetization reorientation in antiferromagnetically coupled Co films and (Co/Pd) multilayers Appl. Phys. Lett. 95, 242502 (2009); 10... the magnetization of one of the magnetic electrodes is canted, forming non-collinear magnetic configurations between layers, should reduce substantially the writing energy of these devices.5–7 These last systems can be real- ized using asymmetric SAFs, where fine...

  13. Pressurized water nuclear reactor system with hot leg vortex mitigator

    DOE Patents [OSTI]

    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.

  14. Vortex energy and 360 Neel walls in thinfilm

    E-Print Network [OSTI]

    .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

  15. Vortex topology and the continuum limit of lattice gauge theories

    E-Print Network [OSTI]

    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.

  16. Reduction of the planar 4-vortex system at zero momentum

    E-Print Network [OSTI]

    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) · z ei z + a. A momentum mapping is Jpl - N n=1 n 1 2 |zn|2]. To calculate the quotient µe : (Jpl )-1 (µe) (Ppl )µe (Jpl )-1 (µe)/SE(2), one may first translate

  17. Vortex energy and 360 Neel wall in thinfilm

    E-Print Network [OSTI]

    Ignat, Radu

    .Ignat@math.u-psud.fr) Courant Institute, New York University, New York, NY 10012, USA (e-mail: knuepfer@cims.nyu.edu) 1 #12 of the magnetization in thickness direction as well as its out of plane component are energetically strongly penalized of a single vortex at the center of the disc. The aim of our paper is to analyze the energetic cost

  18. Transient vortex events in the initial value problem for turbulence

    E-Print Network [OSTI]

    Darryl D. Holm; Robert M. Kerr

    2001-10-19T23:59:59.000Z

    A vorticity surge event that could be a paradigm for a wide class of bursting events in turbulence is studied to examine how the energy cascade is established and how this event could serve as a new test of LES turbulence models. This vorticity surge event is tied to the formation of the energy cascade in a direct numerical simulation by the traditional signatures of a turbulent energy cascade such as spectra approaching -5/3 and strongly Beltramized vortex tubes. A coherent mechanism is suggested by the nearly simultaneous development of a maximum of the peak vorticity $\\|\\omega\\|_\\infty$, growth of the dissipation, the appearance of a helically aligned local vortex configuration and strong, transient oscillations in the helicity wavenumber spectrum. This coherence is also examined for two LES models, a traditional purely dissipative eddy viscosity model and a modern method (LANS$-\\alpha$) that respects the nonlinear transport properties of fluids. Both LES models properly represent the spectral energy and energy dissipation associated with this vorticity surge event. However, only the model that preserves nonlinear fluid transport properties reproduces the helical properties, including Beltrami-like vortex tubes.

  19. E-Print Network 3.0 - axisymmetric vortex breakdown Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the breakdown of vortex rings in the cycle following t 300T. Downstream... A straight tube with a smooth axisymmetric constriction is an idealised representation of a stenosed...

  20. Phase diagram and magnetic structure investigation of the fcc antiferromagnet HoB{sub 12}

    SciTech Connect (OSTI)

    Kohout, A.; Meissner, M.; Siemensmeyer, K. [Hahn Meitner Institut, Glienicker Str. 100, D-14109 Berlin (Germany); Batko, I.; Matas, S. [Hahn Meitner Institut, Glienicker Str. 100, D-14109 Berlin (Germany); Centre of Low Temperature Physics, Institute of Experimental Physics, Slovak Academy of Sciences, SK-04353 Kosice (Slovakia); Czopnik, A. [Institute of Low Temperature and Structure Research, PAS, PL-50950 Wroclaw (Poland); Flachbart, K. [Centre of Low Temperature Physics, Institute of Experimental Physics, Slovak Academy of Sciences, SK-04353 Kosice (Slovakia); Paderno, Y.; Shitsevalova, N. [Institute for Problems of Material Science, NASU, UA-252680 Kiev (Ukraine)

    2004-12-01T23:59:59.000Z

    We have investigated the magnetic structure of the fcc antiferromagnet HoB{sub 12} by magnetization and specific heat measurements on small single crystals prepared from natural elements and by neutron diffraction on isotopically enriched powder samples. Magnetization measurements up to 9 T show up to three magnetic phases in the B vs T phase diagram, depending on the orientation of the applied field. The specific heat in zero field exhibits a very steep increase at T{sub N}=7.4 K, but its maximum is reached only at a lower temperature. In applied magnetic field up to 8 T additional {lambda}-like anomalies are observed which confirm the phase boundaries from the magnetization measurements. Powder neutron diffraction in zero magnetic field reveals an antiferromagnetic structure below T{sub N}. The basic reflections can be indexed with (1/2{+-}{delta} 1/2{+-}{delta} 1/2{+-}{delta}), where {delta}=0.035, pointing to an incommensurate magnetic structure. In a field below 2 T (in the lowest-field magnetic phase) the principal reflections remain; in a higher magnetic field they become suppressed. Moreover, the magnetic background strongly decreases with applied field. The analysis of results shows that an amplitude-modulated, incommensurate structure likely represents the magnetic order of HoB{sub 12}. The very complex phase diagram of this compound can arise from the interplay between the RKKY and dipole-dipole interaction and/or from frustration effects in the fcc-symmetry lattice.

  1. Vortex-induced vibration of a circular cylinder with combined in-line and cross-flow motion

    E-Print Network [OSTI]

    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 ...

  2. PHYSICAL REVIEW B 84, 144511 (2011) Rectification of vortex motion in a circular ratchet channel

    E-Print Network [OSTI]

    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

  3. Generalized London free energy for high-Tc vortex lattices Ian Affleck

    E-Print Network [OSTI]

    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

  4. The geometric phase and the geometrodynamics of relativistic electron vortex beams

    E-Print Network [OSTI]

    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.

  5. Progress in year 2001 1. Observation of Vortex Lattices in Bose-Einstein Condensates

    E-Print Network [OSTI]

    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

  6. van Hove singularities and vortex motion in superconductors B. I. Ivlev,1,2

    E-Print Network [OSTI]

    Kunchur, Milind N.

    ´ 78000, Mexico Received 16 February 2001; published 18 June 2001 When vortices move in a type by an electric current, any peculiarity of the vortex radiation friction due to emission of acoustic waves vortices. When a vortex moves under the action of a transport electric current, an electric field

  7. Nucleation-controlled vortex entry in a square-columnar Josephson-junction array

    SciTech Connect (OSTI)

    Chen, D.; Moreno, J.J.; Hernando, A. [Instituto de Magnetismo Aplicado, RENFE-UCM-CSIC, 28230 Las Rozas, Madrid (Spain)] [Instituto de Magnetismo Aplicado, RENFE-UCM-CSIC, 28230 Las Rozas, Madrid (Spain)

    1997-08-01T23:59:59.000Z

    The initial magnetization curve of square-columnar Josephson-junction arrays is calculated from fundamental laws. It is found that the first vortex entry is controlled by vortex nucleation rather than surface depinning and it occurs at a field greater than that predicted by the traditional surface-barrier theory. {copyright} {ital 1997} {ital The American Physical Society}

  8. Generation and Propagation of InertiaGravity Waves from Vortex Dipoles and Jets SHUGUANG WANG*

    E-Print Network [OSTI]

    Generation and Propagation of Inertia­Gravity Waves from Vortex Dipoles and Jets SHUGUANG WANG) ABSTRACT This study investigates gravity wave generation and propagation from jets within idealized vortex, geostrophic adjust- ment, and spontaneous generation (Fritts and Alexander 2003, and references therein

  9. Vortex ratchet effects in films with a periodic array of antidots Clcio C. de Souza Silva,1,

    E-Print Network [OSTI]

    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

  10. Effect of time-dependent piston velocity program on vortex ring formation in a piston/cylinder arrangement

    E-Print Network [OSTI]

    Dabiri, John O.

    Effect of time-dependent piston velocity program on vortex ring formation in a piston An analytical model describing laminar vortex ring formation in a nozzle flow generator piston/ cylinder.1063/1.2188918 I. INTRODUCTION Vortex rings are usually generated in the laboratory by the motion of a piston

  11. arXiv:1206.2498v2[cond-mat.other]19Nov2012 Quantum vortex reconnections

    E-Print Network [OSTI]

    Caliari, Marco

    , and parts of the initial vortical tubes can be left behind as vortex threads, which then undergo successivearXiv:1206.2498v2[cond-mat.other]19Nov2012 Quantum vortex reconnections S. Zuccher,1 M. Caliari,1 A with time before and after the vor- tex reconnection. We also compute vortex reconnections using the Biot

  12. The role of boundary conditions in a simple model of incipient vortex breakdown F. Gallaire and J.-M. Chomaz

    E-Print Network [OSTI]

    Boyer, Edmond

    . In the labora- tory, it is preferentially studied in vortex tubes, where it is seen in many cases to give riseThe role of boundary conditions in a simple model of incipient vortex breakdown F. Gallaire and J of a hairpin vortex in a shear-thinning fluid governed by a power-law model Phys. Fluids 25, 101703 (2013); 10

  13. Quantum dynamics of a vortex in a Josephson junction

    SciTech Connect (OSTI)

    Li Hong; Liu Wuming [Joint Laboratory of Advanced Technology in Measurements, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Shen Shunqing [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (China); Liang Jiuqing [Institute of Theoretical Physics, Shanxi University, Taiyuan, Shanxi 030006 (China)

    2005-07-01T23:59:59.000Z

    We investigate the tunneling character of vortex in an asymmetrical potential well with a finite barrier by using the periodic instanton method. We obtain the total decay rate which is valid for the entire range of temperature and show how it reduces to the appropriate results for the classical thermal activation at high temperatures, the thermally assisted tunneling at intermediate temperatures, and the pure quantum tunneling at low temperature. We can even give the exact definition of the 'crossover' temperature and find experimental data to support our theoretical analysis.

  14. Magnetic Vortex Core Reversal by Low-Field Excitations

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and InterfacesAdministration -Lowell L.FallU .Magnetic Vortex Core Reversal

  15. Magnetic Vortex Core Reversal by Low-Field Excitations

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and InterfacesAdministration -Lowell L.FallU .Magnetic Vortex Core

  16. Magnetic Vortex Core Reversal by Low-Field Excitations

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and InterfacesAdministration -Lowell L.FallU .Magnetic Vortex CoreMagnetic

  17. Magnetic Vortex Core Reversal by Low-Field Excitations

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and InterfacesAdministration -Lowell L.FallU .Magnetic Vortex

  18. Interaction of Josephson Junction and Distant Vortex in Narrow Thin-Film Superconducting Strips

    SciTech Connect (OSTI)

    Kogan, V. G. [Ames Laboratory; Mints, R. G. [Tel Aviv University

    2014-01-31T23:59:59.000Z

    The phase difference between the banks of an edge-type planar Josephson junction crossing the narrow thin-film strip depends on wether or not vortices are present in the junction banks. For a vortex close to the junction this effect has been seen by Golod, Rydh, and Krasnov [Phys. Rev. Lett. 104, 227003 (2010)], who showed that the vortex may turn the junction into ? type. It is shown here that even if the vortex is far away from the junction, it still changes the 0 junction to a ? junction when situated close to the strip edges. Within the approximation used, the effect is independent of the vortex-junction separation, a manifestation of the topology of the vortex phase which extends to macroscopic distances of superconducting coherence.

  19. Vortex nozzle for segmenting and transporting metal chips from turning operations

    DOE Patents [OSTI]

    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.

  20. Geometric phase of a central spin coupled to an antiferromagnetic environment

    E-Print Network [OSTI]

    Xiao-Zhong Yuan; Hsi-Sheng Goan; Ka-Di Zhu

    2010-03-05T23:59:59.000Z

    Using the spin-wave approximation, we study the geometric phase (GP) of a central spin (signal qubit) coupled to an antiferromagnetic (AF) environment under the application of an external global magnetic field. The external magnetic field affects the GP of the qubit directly and also indirectly through its effect on the AF environment. We find that when the applied magnetic field is increased to the critical magnetic field point, the AF environment undergoes a spin-flop transition, a first-order phase transition, and at the same time the GP of the qubit changes abruptly to zero. This sensitive change of the GP of a signal qubit to the parameter change of a many-body environment near its critical point may serve as another efficient tool or witness to study the many-body phase transition. The influences of the AF environment temperature and crystal anisotropy field on the GP are also investigated.

  1. Magnetically dependent superconducting transport in oxide heterostructures with an antiferromagnetic layer

    SciTech Connect (OSTI)

    Kislinskii, Y. V.; Konstantinian, K. Y., E-mail: karen@hitech.cplire.ru; Ovsyannikov, G. A.; Komissinskiy, P. V.; Borisenko, I. V.; Shadrin, A. V. [Russian Academy of Sciences, Institute of Radio Engineering and Electronics (Russian Federation)

    2008-04-15T23:59:59.000Z

    The superconducting current in hybrid superconducting structures Nb/Au/Ca{sub 1-x}Sr{sub x}CuO{sub 2}/YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} with an antiferromagnetic layer is experimentally shown to have a Josephson nature, and the deviation from the sinusoidal dependence of the superconducting current on the phase difference between superconducting electrodes is about 20% of the second harmonic. These heterostructures are found to have sensitivity to an applied magnetic field that is much higher than that of conventional Josephson junctions. The experimental shape of the magnetic-field dependence of the critical current in the heterostructures differs from the usual Fraunhofer shape by oscillation with a significantly smaller period along a magnetic field.

  2. The Relation Between Dry Vortex Merger and Tropical Cyclone Genesis over the Atlantic Ocean

    SciTech Connect (OSTI)

    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.

  3. Glass-like recovery of antiferromagnetic spin ordering in a photo-excited manganite Pr0.7Ca0.3MnO3

    SciTech Connect (OSTI)

    Zhou, S.Y.; Langner, M.C.; Zhu, Y.; Chuang, Y.-D.; Rini, M.; Glover, T.E.; Hertlein, M.P.; Gonzalez, A.G. Cruz; Tahir, N.; Tomioka, Y.; Tokura, Y.; Hussain, Z.; Schoenlein, R.W.

    2014-01-16T23:59:59.000Z

    Electronic orderings of charges, orbitals and spins are observed in many strongly correlated electron materials, and revealing their dynamics is a critical step toward understanding the underlying physics of important emergent phenomena. Here we use time-resolved resonant soft x-ray scattering spectroscopy to probe the dynamics of antiferromagnetic spin ordering in the manganite Pr0:7Ca0:3MnO3 following ultrafast photo-exitation. Our studies reveal a glass-like recovery of the spin ordering and a crossover in the dimensionality of the restoring interaction from quasi-1D at low pump fluence to 3D at high pump fluence. This behavior arises from the metastable state created by photo-excitation, a state characterized by spin disordered metallic droplets within the larger charge- and spin-ordered insulating domains. Comparison with time-resolved resistivity measurements suggests that the collapse of spin ordering is correlated with the insulator-to-metal transition, but the recovery of the insulating phase does not depend on the re-establishment of the spin ordering.

  4. Quantum Oscillations in the Parent pnictide BaFe2As2 : Itinerant Electrons in the Reconstructed State

    SciTech Connect (OSTI)

    Analytis, J.G.

    2010-05-26T23:59:59.000Z

    We report quantum oscillation measurements that enable the direct observation of the Fermi surface of the low temperature ground state of BaFe{sub 2}As{sub 2}. From these measurements we characterize the low energy excitations, revealing that the Fermi surface is reconstructed in the antiferromagnetic state, but leaving itinerant electrons in its wake. The present measurements are consistent with a conventional band folding picture of the antiferromagnetic ground state, placing important limits on the topology and size of the Fermi surface.

  5. Magnetic response of holographic Lifshitz superconductors:Vortex and Droplet solutions

    E-Print Network [OSTI]

    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.

  6. Exact moduli space metrics for hyperbolic vortex polygons

    SciTech Connect (OSTI)

    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.

  7. Vortex and gap generation in gauge models of graphene

    E-Print Network [OSTI]

    O. Oliveira; C. E. Cordeiro; A. Delfino; W. de Paula; T. Frederico

    2010-12-21T23:59:59.000Z

    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.

  8. Vortex radiation in long narrow Josephson junctions: Theory and experiment

    SciTech Connect (OSTI)

    Abdumalikov, A.A. Jr.; Ustinov, A.V. [Physikalisches Institut III, Universitaet Erlangen-Nuernberg, D-91058 Erlangen (Germany); Fistul, M.V. [Theoretische Physik III, Ruhr-Universitaet Bochum, D-44801 Bochum (Germany)

    2005-10-01T23:59:59.000Z

    We study theoretically and experimentally the dynamics of vortices in long, extremely narrow Josephson junctions. Using a variational approach, the current-voltage characteristics are calculated for junctions of different widths. The analytically and numerically calculated current-voltage characteristics show good agreement. We find that the decrease of the junction width leads to a substantial increase of the maximum velocity of vortices. Due to the interaction with stray magnetic fields outside the junction, the vortices radiate Cherenkov waves as they move in the junction. Locking of the vortex oscillation frequency to that of the Cherenkov radiation leads to novel resonances on the current-voltage characteristics. We observe such resonances in experiments, and their voltage positions and current magnitudes are in qualitative agreement with our theoretical analysis.

  9. Gas turbine engine combustor can with trapped vortex cavity

    DOE Patents [OSTI]

    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.

  10. Spectral Techniques for Solving PDE Stability Model of Vortex Rope

    E-Print Network [OSTI]

    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.

  11. Effect of traveling waves on Vortex-Induced Vibration of long flexible cylinders

    E-Print Network [OSTI]

    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 ...

  12. Vortex-induced vibration of flexible cylinders in time-varying flows

    E-Print Network [OSTI]

    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 ...

  13. Vortex-Induced Vibration of a slender horizontal cylinder in currents and waves

    E-Print Network [OSTI]

    Chitwood, James Scott

    2012-06-07T23:59:59.000Z

    Vortex-Induced Vibration (VIV) is a concern when dealing with slender, flexible structural members of deepwater platforms. While much is known about the characteristics of VIV in uniform and sheared current flows, very little is known about...

  14. Under consideration for publication in J. Fluid Mech. 1 Mixing in a vortex breakdown flow

    E-Print Network [OSTI]

    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

  15. The vortex merger rate in freely decaying, two-dimensional turbulence J. H. LaCascea

    E-Print Network [OSTI]

    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

  16. Dynamical mass of a quantum vortex in a Josephson junction array

    SciTech Connect (OSTI)

    Eckern, U. [Institut fuer Physik, Universitaet Augsburg, D-86135 Augsburg (Germany)] [Institut fuer Physik, Universitaet Augsburg, D-86135 Augsburg (Germany); Luciano, G.; Tagliacozzo, A. [Dipartimento di Scienze Fisiche, Universita di Napoli, Mostra dOltremare Pad. 19, I-80125 Napoli (Italy)] [Dipartimento di Scienze Fisiche, Universita di Napoli, Mostra dOltremare Pad. 19, I-80125 Napoli (Italy); [Istituto Nazionale di Fisica della Materia (INFM), I-16152 Genova (Italy)

    1997-12-01T23:59:59.000Z

    The real-time response to a small external perturbation of a vortex in a quantum Josephson junction array, with long-range Coulomb interaction between Cooper pairs, is analyzed. While the static damping is zero for vortex velocities below some threshold value v{sub th} (which implies the possibility of ballistic motion), a dynamical friction due to the coupling to the plasma oscillations is always present for frequencies higher than a given threshold {omega}{sub th}. The latter approaches zero when the velocity increases to v{sub th}. However, radiative dissipation of the vortex affects the threshold for ballistic motion. We discuss the conditions under which a mass can be defined for the vortex as a quantum particle. {copyright} {ital 1997} {ital The American Physical Society}

  17. E-Print Network 3.0 - axially-symmetric cyclonic vortex Sample...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    > >> 1 1 APRIL 2002 1213W A N G 2002 American Meteorological Society Summary: and wind fields of the vortex Rossby waves are quasi-balanced, with confluent cyclonic (divergent... ,...

  18. Effects of trailing edge flap dynamic deployment on blade-vortex interactions

    E-Print Network [OSTI]

    Nelson, Carter T.

    2012-06-07T23:59:59.000Z

    A theoretical and experimental investigation is undertaken to determine the effects of an actively deployable trailing edge flap on the disturbances created during blade-vortex interactions (BVI). The theoretical model consists of an unsteady panel...

  19. An adaptive mesh method for the simulation of Blade Vortex Interaction

    E-Print Network [OSTI]

    Kim, Kyu-Sup

    2012-06-07T23:59:59.000Z

    An adaptive mesh method for the simulation of parallel ics. Blade Vortex Interaction (BV1) with an active Trailing Edge Flap (TEF) is presented. The two-dimensional 1111-steady problem is solved by a higher order upwind Euler method...

  20. Vortex life cycles in two-and three-layer quasi-geostrophic models

    E-Print Network [OSTI]

    Fox, Amanda Katherine

    2012-06-07T23:59:59.000Z

    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...

  1. Annular Vortex Generation for Inertial Fusion Energy Beam-Line Protection

    SciTech Connect (OSTI)

    Pemberton, Steven J.; Abbott, Ryan P.; Peterson, Per F. [University of California (United States)

    2003-05-15T23:59:59.000Z

    The use of swirling annular vortex flow inside beam entrance tubes can protect beam-line structural materials in chambers for heavy-ion inertial fusion energy (IFE) applications. An annular wall jet, or vortex tube, is generated by injecting liquid tangent to the inner surface of a tube wall with both axially and azimuthally directed velocity components. A layer of liquid then lines the beam tube wall, which may improve the effectiveness of neutron shielding, and condenses and removes vaporized coolant that may enter the beam tubes. Vortex tubes have been constructed and tested with a thickness of three-tenths the pipe radius. Analysis of the flow is given, along with experimental examples of vortex tube fluid mechanics and an estimate of the layer thickness, based on simple mass conservation considerations.

  2. On the vortex parameter estimation using wide band signals in active acoustic system

    E-Print Network [OSTI]

    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

  3. Enhancement of vortex induced forces and motion through surface roughness control

    DOE Patents [OSTI]

    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).

  4. Application of the vortex-box method to the unsteady incompressible flow over finite wings

    E-Print Network [OSTI]

    Soncrant, Charles Upton

    2012-06-07T23:59:59.000Z

    APPLICATION OP THE VORTEX-BOX MRTHOD TO THE UNSTEADT INCOMPRESSIBLE FLOW OVER FINITE WINGS A Thesis by CHARLES UPTON SONCRANT Submitted to the Graduate College of Texas AAM University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE May 1973 Major Subject: Aerospace Engineering APPLICATION OF THE VORTEX-BOX METHOD TO THE UNSTEADY INCOMPRESSIBLE FLOW OVER FINITE WINGS A Thesis by CHARLES UPTON SONCRANT Approved as to style and content by: (Chairman...

  5. Effect of a surface boundary layer on an intensifying, downward-propagating vortex

    E-Print Network [OSTI]

    Wood, Vincent Tunstall

    2012-06-07T23:59:59.000Z

    EFFECT OF A SURFACE BOUNDARY LAYER ON AN INTENSIFYING, DOWNWARD-PROPAGATING VORTEX A Thesis by VINCENT TUNSTALL WOOD Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE May 1977 Major Subject: Meteorology EFFECT OF A SURFACE BOUNDARY LAYER ON AN INTENSIFYING, DOWNWARD-PROPAGATING VORTEX A Thesis by VINCENT TUNSTALL WOOD Approved as to style and content by: (Chairman of Committee) (Head of Department...

  6. Vortex in a weakly relativistic Bose gas at zero temperature and relativistic fluid approximation

    E-Print Network [OSTI]

    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.

  7. Explicit mean-field radius for nearly parallel vortex filaments in statistical equilibrium

    E-Print Network [OSTI]

    Timothy D. Andersen; Chjan C. Lim

    2006-11-19T23:59:59.000Z

    Geophysical research has focused on flows, such as ocean currents, as two dimensional. Two dimensional point or blob vortex models have the advantage of having a Hamiltonian, whereas 3D vortex filament or tube systems do not necessarily have one, although they do have action functionals. On the other hand, certain classes of 3D vortex models called nearly parallel vortex filament models do have a Hamiltonian and are more accurate descriptions of geophysical and atmospheric flows than purely 2D models, especially at smaller scales. In these ``quasi-2D'' models we replace 2D point vortices with vortex filaments that are very straight and nearly parallel but have Brownian variations along their lengths due to local self-induction. When very straight, quasi-2D filaments are expected to have virtually the same planar density distributions as 2D models. An open problem is when quasi-2D model statistics behave differently than those of the related 2D system and how this difference is manifested. In this paper we study the nearly parallel vortex filament model of Klein, Majda, Damodaran in statistical equilibrium. We are able to obtain a free-energy functional for the system in a non-extensive thermodynamic limit that is a function of the mean square vortex position $R^2$ and solve \\emph{explicitly} for $R^2$. Such an explicit formula has never been obtained for a non-2D model. We compare the results of our formula to a 2-D formula of \\cite{Lim:2005} and show qualitatively different behavior even when we disallow vortex braiding. We further confirm our results using Path Integral Monte Carlo (Ceperley (1995)) \\emph{without} permutations and that the Klein, Majda, Damodaran model's asymptotic assumptions \\emph{are valid} for parameters where these deviations occur.

  8. Static solitons of the sine-Gordon equation and equilibrium vortex structure in Josephson junctions

    SciTech Connect (OSTI)

    Kuplevakhsky, S. V.; Glukhov, A. M. [B. I. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin Avenue, 61103 Kharkov (Ukraine)

    2006-01-01T23:59:59.000Z

    The problem of vortex structure in a single Josephson junction in an external magnetic field, in the absence of transport currents, is reconsidered from a new mathematical point of view. In particular, we derive a complete set of exact analytical solutions representing all the stationary points (minima and saddle-points) of the relevant Gibbs free-energy functional. The type of these solutions is determined by explicit evaluation of the second variation of the Gibbs free-energy functional. The stable (physical) solutions minimizing the Gibbs free-energy functional form an infinite set and are labeled by a topological number N{sub v}=0,1,2,... . Mathematically, they can be interpreted as nontrivial 'vacuum' (N{sub v}=0) and static topological solitons (N{sub v}=1,2,...) of the sine-Gordon equation for the phase difference in a finite spatial interval: solutions of this kind were not considered in previous literature. Physically, they represent the Meissner state (N{sub v}=0) and Josephson vortices (N{sub v}=1,2,...). Major properties of the new physical solutions are thoroughly discussed. An exact, closed-form analytical expression for the Gibbs free energy is derived and analyzed numerically. Unstable (saddle-point) solutions are also classified and discussed.

  9. Twisted toroidal vortex-solitons in inhomogeneous media with repulsive nonlinearity

    E-Print Network [OSTI]

    Y. V. Kartashov; B. A. Malomed; Y. Shnir; L. Torner

    2014-12-05T23:59:59.000Z

    Toroidal modes in the form of so-called Hopfions, with two independent winding numbers, a hidden one (twist, s), which characterizes a circular vortex thread embedded into a three-dimensional soliton, and the vorticity around the vertical axis m, appear in many fields, including the field theory, ferromagnetics, and semi- and superconductors. Such topological states are normally generated in multi-component systems, or as trapped quasi-linear modes in toroidal potentials. We uncover that stable solitons with this structure can be created, without any linear potential, in the single-component setting with the strength of repulsive nonlinearity growing fast enough from the center to the periphery, for both steep and smooth modulation profiles. Toroidal modes with s=1 and vorticity m=0,1,2 are produced. They are stable for m1. An approximate analytical solution is obtained for the twisted ring with s=1, m=0. Under the application of an external torque, it rotates like a solid ring. The setting can be implemented in BEC, by means of the Feshbach resonance controlled by inhomogene-ous magnetic fields.

  10. Coexisting multiple dynamic states generated by magnetic field in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}+{delta} stacked Josephson junctions.

    SciTech Connect (OSTI)

    Jin, Y.-D.; Lee, H-J.; Koshe.lev, A. E.; Lee, G.-H.; Bae, M.-H.; Materials Science Division; Pohang Univ. of Science and Technology; Univ. of Illinois

    2009-10-09T23:59:59.000Z

    Josephson vortices in naturally stacked Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} tunneling junctions display rich dynamic behavior that derives from the coexistence of three basic states: static Josephson vortex lattice, coherently moving lattice, and incoherent quasiparticle tunneling state. The rich structure of hysteretic branches observed in the current-voltage characteristics can be understood as combinatorial combinations of these three states which are realized in different junctions and evolve separately with magnetic field and bias current. In particular, the multiple Josephson vortex flow branches at low-bias currents arise from the individual depinning of Josephson vortex rows in each junction.

  11. The internal structure of a vortex in a two-dimensional superfluid with long healing length and its implications

    SciTech Connect (OSTI)

    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.

  12. Charge control of antiferromagnetism at PbZr{sub 0.52}Ti{sub 0.48}O{sub 3}/La{sub 0.67}Sr{sub 0.33}MnO{sub 3} interface

    SciTech Connect (OSTI)

    Ma, X.; Zhai, H.; Fang, F.; Lüpke, G., E-mail: gxluep@wm.edu [Department of Applied Science, College of William and Mary, 251 Jamestown Road, Williamsburg, Virginia 23187 (United States); Kumar, A. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931-3343 (United States); CSIR-National Physical Laboratory, New Delhi 110012 (India); Dussan, S.; Katiyar, R. S. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931-3343 (United States); Zhao, H. B. [Department of Optical Science and Engineering, Fudan University, 220 Handan Road, Shanghai 200433 (China); Scott, J. F. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931-3343 (United States); Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 OHE (United Kingdom)

    2014-03-31T23:59:59.000Z

    The interfacial spin state of the multiferroic heterostructure PbZr{sub 0.52}Ti{sub 0.48}O{sub 3}/La{sub 0.67}Sr{sub 0.33}MnO{sub 3} and its dependence on ferroelectric polarization is investigated with magnetic second-harmonic generation at 78?K. The spin alignment of Mn ions in the first unit cell layer at the heterointerface can be tuned from ferromagnetic to antiferromagnetic exchange coupled, while the bulk magnetization remains unchanged. Multiple domains of both phases coexist as the ferroelectric polarization is switched. The results will help promote the development of new interface-based functionalities and device concepts.

  13. Novel alkaline earth copper germanates with ferro and antiferromagnetic S=1/2 chains

    SciTech Connect (OSTI)

    Brandao, Paula [University of Aveiro, Portugal; Reis, Mario S [Universidade Federal Fluminense, Brasil; Gai, Zheng [ORNL; Moreira Dos Santos, Antonio F [ORNL

    2013-01-01T23:59:59.000Z

    Two new alkaline earth copper(II) germanates were hydrothermally synthesized: CaCuGeO4 center dot H2O (1) and BaCu2Ge3O9 center dot H2O (2), and their structures determined by single crystal X-ray diffraction. Compound (1) crystallizes in space group P2(1)/c with a=5.1320(2) angstrom, b=16.1637(5) angstrom, c=5.4818(2) angstrom, beta=102.609(2)degrees, V=443.76(3) angstrom(3) and Z=4. This copper germanate contains layers of composition [CuGeO4](infinity)(2-) comprising CuO4 square planes and GeO4 tetrahedra with calcium and water molecules in the inter-layer space. Compound (2) crystallizes in the Cmcm space group with a=5.5593(3) angstrom, b=10.8606(9) angstrom, c=13.5409(8) angstrom, V=817.56(9) angstrom(3) and Z=4. This structure contains GeO6 and CuO6 octahedra as well as GeO4 tetrahedra, forming a three-dimensional network of interconnecting six-membered ring channels. The magnetic susceptibility for both samples can be interpreted as S=1/2 chains, in agreement with the copper topology observed in the crystal structure. The susceptibility of (1) exhibits a Bonner-Fisher type behavior, resulting from antiferromagnetic intra-chain interactions without three-dimensional ordering down to 5 K-the lowest measured temperature. This observation, together with the absence of super-exchange paths between the copper chains, make this system particularly promising for the study of low dimensional magnetism. The magnetic properties of (2) show a very weak ferromagnetic near-neighbor interaction along the chain. In this compound a peak the chi T plot seems to indicate the onset of interchain antiferromagentic correlations. However, no ordering temperature is detected in the susceptibility data.

  14. Helical antiferromagnetic ordering in Lu1-xScxMnSi

    SciTech Connect (OSTI)

    Goetsch, Ryan J [Ames Laboratory; Anand, V K [Ames Laboratory; Johnston, David C [Ames Laboratory

    2014-08-01T23:59:59.000Z

    Polycrystalline samples of Lu1?xScxMnSi (x=0, 0.25, 0.5) are studied using powder x-ray diffraction, heat capacity Cp, magnetization, magnetic susceptibility ?, and electrical resistivity ? measurements versus temperature T and magnetic field H. This system crystallizes in the primitive orthorhombic TiNiSi-type structure (space group Pnma) as previously reported. The ?(T) data indicate metallic behavior. The Cp(T), ?(T), and ?(T) measurements consistently indicate long-range antiferromagnetic (AF) transitions with AF ordering temperatures TN=246, 215, and 188 K for x=0, 0.25, and 0.5, respectively. A second transition is observed at somewhat lower T for each sample from the ?(T) and ?(T) measurements, which we speculate are due to spin reorientation transitions; these second transitions are completely suppressed in H=5.5 T. The Cp data below 10 K for each composition indicate an enhanced Sommerfeld electronic heat capacity coefficient for the series in the range ?=24–29 mJ/mol K2. The ?(T) measurements up to 1000 K were fitted by local-moment Curie-Weiss behaviors which indicate a low Mn spin S?1. The ? data below TN are analyzed using the Weiss molecular field theory for a planar noncollinear cycloidal AF structure with a composition-dependent pitch, following the previous neutron diffraction work of Venturini et al. [J. Alloys Compd. 256, 65 (1997)]. Within this model, the fits indicate a turn angle between Mn ordered moments along the cycloid axis of ?100? or ?145?, either of which indicate dominant AF interactions between the Mn spins in the Lu1?xScxMnSi series of compounds.

  15. Dynamics of a relativistic Rankine vortex for a two-constituent superfluid in a weak perturbation of cylindrical symmetry

    E-Print Network [OSTI]

    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.

  16. Vortex generation in protoplanetary disks with an embedded giant planet

    E-Print Network [OSTI]

    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 $\

  17. Transitions between turbulent and laminar superfluid vorticity states in the outer core of a neutron star

    E-Print Network [OSTI]

    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.

  18. A Robust Numerical Method for Integration of Point-Vortex Trajectories in Two Dimensions

    E-Print Network [OSTI]

    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.

  19. Characterization of The Dalles Dam Spillbay 6 Vortex Using Surface Entrained Sensor Fish Device: Preliminary Report

    SciTech Connect (OSTI)

    Deng, Zhiqun; Richmond, Marshall C.; Carlson, Thomas J.

    2006-06-22T23:59:59.000Z

    This document summarizes the pilot study to characterize The Dalles Dam Spillbay 6 vortex using a surface entrained Sensor Fish device. It was conducted by Pacific Northwest National Laboratory (PNNL) on April 13 and 14, 2006. The total spill was controlled at approximately 110 kcfs, the forebay elevation was 157.89 ft, and the discharge of Bay 6 at the tested gate opening of 14 ft was approximately 18 kcfs. The objectives of the full study are to (1) develop baseline conditions for the detailed analysis of Sensor Fish measurements by deploying Sensor Fish in different surface locations in the vortex periphery; (2) observe the entrainment pattern and extract hydraulic data of interest such as acceleration, rotation, pressure, and estimated velocity of Sensor Fish or drogues; (3) integrate the experimental results with companion computational fluid dynamics (CFD) simulations and inertial particle tracking studies. A total of 12 Sensor Fish were released in the surface at upstream edge, left edge, downstream edge, and the core of the vortex at Bay 6. Because of the high discharge, the vortex patterns at the test condition were less consistent than the patterns observed at lower discharges. Compared with the Sensor Fish released at mid-bay at Bay 6, Sensor Fish released from the surface at the vortex experienced higher pressure fluctuations, a larger percentage of severe events, and much more rapid angular velocities.

  20. Bow-wave-like hydraulic jump and horseshoe vortex around an obstacle in a supercritical open channel flow

    E-Print Network [OSTI]

    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

  1. Joule heating induced by vortex motion in a type-II superconductor Z. L. Xiao and E. Y. Andrei

    E-Print Network [OSTI]

    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

  2. Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel beams

    E-Print Network [OSTI]

    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

  3. Method for the assessment of airborne off-target pesticide spray concentrations due to aircraft wing-tip vortex

    E-Print Network [OSTI]

    Oliva, Sergio Eduardo

    2012-06-07T23:59:59.000Z

    that spherical spray droplets are transported by a two dimensional parametric representation of a spray-engulfing aircraft wing-tip vortex pair. Two distinctive flow regions were considered for the spray-vortex dynamics. The first occurs in the vicinity...

  4. Vortex dipoles by PIV method Click here to see the images and the short movies from this lab

    E-Print Network [OSTI]

    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

  5. Reduction of vortex induced forces and motion through surface roughness control

    DOE Patents [OSTI]

    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.

  6. Shear Banding and Spatiotemporal Oscillations in Vortex Matter in Nanostructured Superconductors

    E-Print Network [OSTI]

    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.

  7. Spectro-Polarimetric Properties of Small-Scale Plasma Eruptions Driven by Magnetic Vortex Tubes

    E-Print Network [OSTI]

    Kitiashvili, Irina N

    2014-01-01T23:59:59.000Z

    Highly turbulent nature of convection on the Sun causes strong multi-scale interaction of subsurface layers with the photosphere and chromosphere. According to realistic 3D radiative MHD numerical simulations ubiquitous small-scale vortex tubes are generated by turbulent flows below the visible surface and concentrated in the intergranular lanes. The vortex tubes can capture and amplify magnetic field, penetrate into chromospheric layers and initiate quasi-periodic flow eruptions that generates Alfv\\'enic waves, transport mass and energy into the solar atmosphere. The simulations revealed high-speed flow patterns, and complicated thermodynamic and magnetic structures in the erupting vortex tubes. The spontaneous eruptions are initiated and driven by strong pressure gradients in the near-surface layers, and accelerated by the Lorentz force in the low chromosphere. In this paper, the simulation data are used to further investigate the dynamics of the eruptions, their spectro-polarimetric characteristics for the...

  8. X-ray imaging of vortex cores in confined magnetic structures

    SciTech Connect (OSTI)

    Fischer, P.; Im, M.-Y.; Kasai, S.; Yamada, K.; Ono, T.; Thiaville, A.

    2011-02-11T23:59:59.000Z

    Cores of magnetic vortices in micron-sized NiFe disk structures, with thicknesses between 150 and 50 nm, were imaged and analysed by high resolution magnetic soft X-ray microscopy. A decrease of the vortex core radius was observed, from #24; ~38 to 18 nm with decreasing disk thickness. By comparing with full 3D micromagnetic simulations showing the well-known barrel structure, we obtained excellent agreement taking into account instrumental broadening and a small perpendicular anisotropy. The proven magnetic spatial resolution of better than 25 nm was sufficient to identify a negative dip close to the vortex core, originating from stray fields of the core. Magnetic vortex structures can serve as test objects for evaluating sensitivity and spatial resolution of advanced magnetic microscopy techniques.

  9. Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel

    DOE Patents [OSTI]

    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.

  10. Vortex combustor for low NOx emissions when burning lean premixed high hydrogen content fuel

    DOE Patents [OSTI]

    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.

  11. Role of the Vortex-Core Energy on the Berezinskii-Kosterlitz-Thouless Transition in Thin Films of NbN

    E-Print Network [OSTI]

    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

  12. Antiferromagnetic phase transition in the temperature-dependent NIR-VUV dielectric function of hexagonal YMnO$_3$

    E-Print Network [OSTI]

    Richter, Steffen; Grundmann, Marius; Schmidt-Grund, Rüdiger

    2015-01-01T23:59:59.000Z

    Hexagonal YMnO$_3$ is well known for the co-occurrence of ferroelectricity and antiferromagnetism at low temperatures. Using temperature-dependent spectroscopic ellipsometry at an $a$-plane oriented single crystal, we show how the dielectric function is affected by the magnetic order transition at the N\\'eel temperature. We focus especially on the pronounced charge transfer transitions around (1.6-1.7)eV which are strongly connected to Mn 3$d$ electrons. If described with a Bose-Einstein model, the temperature dependency of their energy and broadening is characterized by effective phonon energies not larger than 8meV. We argue that this is a hint for the occurrence of a soft phonon mode related to the antiferromagnetic phase transition. This is observed in both tensor components of the dielectric function, parallel and perpendicular to the crystallographic $c$-axis. Furthermore, a suitable parametrization for the uniaxial dielectric function is presented for the NIR-VUV spectral range. The broad transitions a...

  13. Phase-locking of driven vortex lattices with transverse ac force and periodic pinning

    SciTech Connect (OSTI)

    Reichhardt, Charles; Kolton, Alejandro B.; Dominguez, Daniel; Gronbech-Jensen, Niels

    2001-10-01T23:59:59.000Z

    For a vortex lattice moving in a periodic array we show analytically and numerically that a new type of phase locking occurs in the presence of a longitudinal dc driving force and a transverse ac driving force. This phase locking is distinct from the Shapiro step phase locking found with longitudinal ac drives. We show that an increase in critical current and a fundamental phase-locked step width scale with the square of the driving ac amplitude. Our results should carry over to other systems such as vortex motion in Josephson-junction arrays.

  14. The effects of a jet on vortex breakdown over a sharp leading-edge delta wing

    E-Print Network [OSTI]

    Maynard, Ian Kenneth

    2012-06-07T23:59:59.000Z

    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...

  15. Correlated vortex pinning in slightly orthorhombic twinned Ba(Fe1-xCox)2As2 single crystals: Possible shift of the vortex-glass/liquid transition

    SciTech Connect (OSTI)

    Bermudez, M. Marziali [Universidad de Buenos Aires; Pasquini, G. [Universidad de Buenos Aires; Budko, Sergey L. [Ames Laboratory; Canfield, Paul C. [Ames Laboratory

    2013-02-28T23:59:59.000Z

    The interest in twin-boundary (TB) planes as a source of vortex pinning has been recently renewed with the discovery of the new iron-arsenide pnictide superconductors. In the family of compounds Ba(Fe1-xCox)2As2 a structural transition from a tetragonal to orthorhombic lattice takes place for compounds with xvortex cores. In this work we investigate the changes in anisotropy produced by subtle differences in the Co doping level, in the neighborhood of the structural transition, in good-quality single crystals. Using a scaling approach we are able to determine the angular regions where correlated or uncorrelated disorder prevails. In the tetragonal samples (x>xcr) there is no twinning and we find good agreement with the expected scaling function under uncorrelated disorder, with small anisotropy values similar to those reported in the literature. We show that in the orthorhombic samples (xvortex liquid-glass transition temperature.

  16. Development of vortex state in circular magnetic nanodots: Theory and experiment RID A-9247-2009

    E-Print Network [OSTI]

    Mejia-Lopez, J.; Altbir, D.; Landeros, P.; Escrig, J.; Romero, A. H.; Roshchin, Igor V.; Li, C-P; Fitzsimmons, M. R.; Batlle, X.; Schuller, Ivan K.

    2010-01-01T23:59:59.000Z

    We compare magnetic reversal of nanostructured circular magnetic dots of different sizes. This comparison is based on superconducting quantum interference device (SQUID) magnetometry, neutron scattering, Monte Carlo simulation, and analytical...

  17. Two regimes of vortex penetration into platelet-shaped type-II superconductors

    SciTech Connect (OSTI)

    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}.

  18. Origin of Reversed Vortex Ratchet Motion W. Gillijns, A. V. Silhanek, and V. V. Moshchalkov

    E-Print Network [OSTI]

    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

  19. Vortex-Pair Dynamics in Anisotropic Bistable Media: A Kinematic Approach Aric Hagberg1

    E-Print Network [OSTI]

    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

  20. Computational Analysis of a Tip Vortex Structure Shed from a Bioinspired Blade

    E-Print Network [OSTI]

    Maccabe, Barney

    design for this purpose. Different rotor blade designs and relevant insect wings are under study Computational Analysis of a Tip Vortex Structure Shed from a Bioinspired Blade Sebastian was generated with SolidWorks CAD software from measurements performed on a wing sample obtained from

  1. VIVDR -Vortex-induced vibration data repository An overview of available riser datasets

    E-Print Network [OSTI]

    VIVDR - Vortex-induced vibration data repository An overview of available riser datasets http://oe.mit.edu/VIV H. Mukundan and M. Triantafyllou 20 April 2008 #12;NDP 38m long riser model datasets #12;33 q Rig q Tension applied through spring-supported clump weights NDP 38m long riser model datasets

  2. Forebay Computational Fluid Dynamics Modeling for The Dalles Dam to Support Vortex Suppress Device Studies

    SciTech Connect (OSTI)

    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.

  3. Tip Vortex Field Resolution Using an Adaptive Dual-Mesh Computational Nathan Hariharan

    E-Print Network [OSTI]

    Steffen, Michael

    for the aforementioned unsteady, vortical fields. 1. Introduction 1.1 Background Vortical wakes introduce important AMR in an unstructured Euler solver. Potsdam[3] also applied unstructured AMR to wind turbine wake1 Tip Vortex Field Resolution Using an Adaptive Dual-Mesh Computational Paradigm Nathan Hariharan

  4. Vortex Rings in Bio-inspired and Biological Jet Propulsion Paul S. Krueger1, a

    E-Print Network [OSTI]

    Hynes, Wayne L.

    , J. Tyler Nichols1,c , Ian K. Bartol2,d , and William J. Stewart2,e 1 Department of Mechanical of the pulse is ejected as a trailing jet. Recent results from mechanical pulsed- jets have demonstrated that vortex rings lead to thrust augmentation through the acceleration of additional ambient fluid

  5. DETECTION OF VORTEX TUBES IN SOLAR GRANULATION FROM OBSERVATIONS WITH SUNRISE

    SciTech Connect (OSTI)

    Steiner, O.; Franz, M.; Bello Gonzalez, N.; Nutto, Ch.; Rezaei, R.; Schmidt, W. [Kiepenheuer-Institut fuer Sonnenphysik, Schoeneckstrasse 6, 79104 Freiburg (Germany); Martinez Pillet, V.; Bonet Navarro, J. A. [Instituto de Astrofisica de Canarias, 38200, La Laguna, Tenerife (Spain); Del Toro Iniesta, J. C. [Instituto de Astrofisica de Andalucia (CSIC), Apdo. de Correos 3004, 18080 Granada (Spain); Domingo, V. [Grupo de Astronomia y Ciencias del Espacio, Universidad de Valencia, 46980 Paterna, Valencia (Spain); Solanki, S. K.; Barthol, P.; Gandorfer, A. [Max-Planck-Institut fuer Sonnensystemforschung, 37191 Katlenburg-Lindau (Germany); Knoelker, M., E-mail: steiner@kis.uni-freiburg.d [High Altitude Observatory, National Center for Atmospheric Research (NCAR), Boulder, CO 80307-3000 (United States)

    2010-11-10T23:59:59.000Z

    We have investigated a time series of continuum intensity maps and corresponding Dopplergrams of granulation in a very quiet solar region at the disk center, recorded with the Imaging Magnetograph eXperiment (IMaX) on board the balloon-borne solar observatory SUNRISE. We find that granules frequently show substructure in the form of lanes composed of a leading bright rim and a trailing dark edge, which move together from the boundary of a granule into the granule itself. We find strikingly similar events in synthesized intensity maps from an ab initio numerical simulation of solar surface convection. From cross sections through the computational domain of the simulation, we conclude that these granular lanes are the visible signature of (horizontally oriented) vortex tubes. The characteristic optical appearance of vortex tubes at the solar surface is explained. We propose that the observed vortex tubes may represent only the large-scale end of a hierarchy of vortex tubes existing near the solar surface.

  6. Vortex Liquid Crystals in Anisotropic Type II Superconductors E.W. Carlson,1,2

    E-Print Network [OSTI]

    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

  7. 2094 OPTICS LETTERS / Vol. 28, No. 21 / November 1, 2003 Fundamental and vortex solitons in a

    E-Print Network [OSTI]

    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

  8. Effect of asymmetric axial strain on the behavior of the juncture vortex system

    E-Print Network [OSTI]

    Trosper, Jeffrey Randall

    2012-06-07T23:59:59.000Z

    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...

  9. Observations of wave-generated vortex ripples on the North Carolina continental shelf

    E-Print Network [OSTI]

    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

  10. Josephson Vortex Qubit: Design, Preparation and Read-Out , A. Wallraff, and A. V. Ustinov

    E-Print Network [OSTI]

    Wallraff, Andreas

    of a qubit based on a single Josephson vortex trapped in a shaped long Josephson junction is discussed on small Josephson junctions in the phase or charge regime have been shown to achieve parameters which Josephson junction was proposed. A major difference from the small Josephson junction qubit proposals where

  11. Combustion in Meso-scale Vortex Chambers Ming-hsun Wu*

    E-Print Network [OSTI]

    Yang, Vigor

    %. For propane/air combustion, the stability limits ranged from ~ 0.25 to 2 for the 124 mm3 combustor. Methane of a small combustor not only makes the heat generated from the combustion process hard to keep pace1 Combustion in Meso-scale Vortex Chambers Ming-hsun Wu* , Yanxing Wang, Vigor Yang and Richard A

  12. Vortex-peak interaction and lattice shape in rotating two-component Bose-Einstein condensates

    E-Print Network [OSTI]

    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

  13. Formation and Decay of Vortex Lattices in Bose-Einstein Condensates at Finite Temperatures

    E-Print Network [OSTI]

    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

  14. ccsd00003161, Vortex patterns in a fast rotating Bose-Einstein condensate

    E-Print Network [OSTI]

    . Furthermore we restrict our analysis to the case of a two-dimensional gas in the xy plane, assumingccsd­00003161, version 1 ­ 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

  15. Indirect Combustion Noise: Experimental Investigation of the Vortex Sound Generation in a Choked

    E-Print Network [OSTI]

    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

  16. Cherenkov resonances in vortex dissipation in superconductors B. I. Ivlev and S. Mejia-Rosales

    E-Print Network [OSTI]

    Kunchur, Milind N.

    , Mexico M. N. Kunchur Department of Physics and Astronomy, University of South Carolina, Columbia, South-two superconductors the magnetic flux is carried by vortices. If the transport electric current greatly exceeds in the crystal the dissipa- tion increases due to Cherenkov emission of sound waves. Each moving vortex creates

  17. ADVANCES IN ATMOSPHERIC SCIENCES, VOL. 27, NO. 2, 2010, 243252 Mesoscale Barotropic Instability of Vortex Rossby

    E-Print Network [OSTI]

    Zhang, Da-Lin

    ADVANCES IN ATMOSPHERIC SCIENCES, VOL. 27, NO. 2, 2010, 243­252 Mesoscale Barotropic Instability of Vortex Rossby Waves in Tropical Cyclones ZHONG Wei1 ( Í), LU Han-Cheng1 (ö ), and Da-Lin ZHANG2 1 Institute of Meteorology, PLA University of Science and Technology, Nanjing 211101 2 Department

  18. First-order disorder-driven transition and inverse melting of the vortex lattice

    E-Print Network [OSTI]

    Zeldov, Eli

    `inverse' melting behavior. � 2001 Published by Elsevier Science B.V. Keywords: Type-II superconductivity-order transition (FOT) [1±5] whereas at low temperatures the ordered vortex lattice transforms into a disordered open questions in the phase diagram of HTS is the thermodynamic nature of the disorder-dri- ven

  19. Direct numerical simulation of autoignition of a hydrogen vortex ring reacting with hot air

    E-Print Network [OSTI]

    Mahesh, Krishnan

    Direct numerical simulation of auto­ignition of a hydrogen vortex ring reacting with hot air Jeff2/air combustion proposed by Mueller et al. [2]. Diluted H2 at ambient temperature (300 K) is injected into hot air. The simulations study the effect of fuel/air ratios, oxidizer temperature, Lewis

  20. Anomalous United States weather patterns accompanying Stratospheric Sudden Warming

    E-Print Network [OSTI]

    Douglas, Donald Albert

    2012-06-07T23:59:59.000Z

    Yearly cyclone frequency over North America and adjacent oceans, corresponding linear regression line and correlation coe f f icient 35 FIG. 12 FIG. 13 As Fig. 11, except for February Yearly January cyclone frequency over the United States..., or to the west of, the United States coastline and in the north central Atlantic Ocean. The ridging then extends northwards over both oceans toward the polar regions. At the same time, the tropo- spheric polar vortex splits into two distinct centers ? one...

  1. arXiv:cond-mat/0702119v16Feb2007 Hole dynamics in an antiferromagnet

    E-Print Network [OSTI]

    that the critical point broadens into a non-Fermi liquid `holon metal' phase with fractionalized excitations. The holon metal phase is flanked on both sides by Fermi liquid states with Fermi surfaces enclosing

  2. Magnetodielectric Effect in the S = 1/2 Quasi-Two-Dimensional Antiferromagnet K2V3O8

    SciTech Connect (OSTI)

    Rai, R. C. [University of Tennessee, Knoxville (UTK); Cao, J. [University of Tennessee, Knoxville (UTK); Musfeldt, J. L. [University of Tennessee, Knoxville (UTK); Singh, David J [ORNL; Wei, X. [Florida State University; Jin, Rongying [ORNL; Zhou, Zhixian [ORNL; Sales, Brian C [ORNL; Mandrus, David [ORNL

    2006-01-01T23:59:59.000Z

    We report the optical and magneto-optical properties of K{sub 2}V{sub 3}O{sub 8}, an S = 1/2 quasi-two-dimensional Heisenberg antiferromagnet. Local spin density approximation electronic structure calculations are used to assign the observed excitations and analyze the field-dependent features. Two large magneto-optical effects, centered at {approx}1.19 and 2.5 eV, are attributed to field-induced changes in the V{sup 4+} d {yields} d on-site excitations due to modification of the local crystal field environment of the VO{sub 5} square pyramids with applied magnetic field. Taken together, the evidence for a soft lattice, the presence of vibrational fine structure on the sharp 1.19 eV magneto-optical feature, and the fact that these optical excitations are due to transitions from a nearly pure spin-polarized V d state to hybridized states involving both V and O, suggest that the magneto-dielectric effect in K{sub 2}V{sub 3}O{sub 8} is driven by strong lattice coupling.

  3. Surface driven effects on magnetic properties of antiferromagnetic LaFeO{sub 3} nanocrystalline ferrite

    SciTech Connect (OSTI)

    Sendil Kumar, A., E-mail: sendilphy@gmail.com, E-mail: anilb42@gmail.com [School of Physics, University of Hyderabad, Hyderabad, Telangana 500 046 (India); Manivel Raja, M. [Advanced Magnetics Group, Defence Metallurgical Research Laboratory, Hyderabad, Telangana 500 058 (India); Bhatnagar, Anil K., E-mail: sendilphy@gmail.com, E-mail: anilb42@gmail.com [School of Physics, University of Hyderabad, Hyderabad, Telangana 500 046 (India); School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad, Telangana 500 046 (India)

    2014-09-21T23:59:59.000Z

    LaFeO{sub 3} nanocrystalline ferrites were synthesized through sol-gel method in different size distributions and the effect of finite size on magnetic properties is investigated. Results of magnetization and Mössbauer measurements show that superparamagnetism and weak ferromagnetic behavior in some of the size distributions. The origin of the superparamagnetism is from fine particles similar to ferromagnetic single domains and the weak ferromagnetism comes from surface spin disorder caused by Dzyaloshinskii-Moriya interaction. The magnetic ground state of LaFeO{sub 3} nanoparticles differs from that of bulk, and the ground state is dictated by the finite size effect because density of states depends on the dimensionality of the sample.

  4. Effects of atmospheric conditions and control surface deflections on vortex characteristics

    E-Print Network [OSTI]

    Shenkir, Calvin Edward

    2012-06-07T23:59:59.000Z

    7, SST Ci'rcorde, C-SA, and others, induce 'tr. ailing r, ing iiI! vor'-ic, s ?aiich pr: sent a hazard Lo stnal1er ait craft. In this Itir!Osti(dation such vr. i tex charac'ieristics as I!ave Fornations, r;0!e Ienrgths, b(eak t&1es, and vortex...''1(is r! ' 0 . L'I' I i I 21, I r'. . r ot' j(IS Ls I'rtn(. 'cst b'r'('1';s OLCLII'I'0 I 11r!01 ' 'I; ' rlr'rr. 'X:' ". :: ":I, '. L '. I'Il . IrI rI(:cray occurred in aparoximately 1/2 the time of a si. -iilsr vortex ! nduced ;. i th ~ head...

  5. Reduced gravity Rankine cycle system design and optimization study with passive vortex phase separation

    E-Print Network [OSTI]

    Supak, Kevin Robert

    2008-10-10T23:59:59.000Z

    REDUCED GRAVITY RANKINE CYCLE SYSTEM DESIGN AND OPTIMIZATION STUDY WITH PASSIVE VORTEX PHASE SEPARATION A Thesis by KEVIN ROBERT SUPAK Submitted to the Office of Graduate Studies of Texas A&M University... SEPARATION A Thesis by KEVIN ROBERT SUPAK 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 Approved by: Chair of Committee, Frederick...

  6. Nanoscale strain-induced pair suppression as a vortex-pinning mechanism in high- temperature superconductors

    SciTech Connect (OSTI)

    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.

  7. Kelvin-Helmholtz instability in a current-vortex sheet at a 3D magnetic null

    SciTech Connect (OSTI)

    Wyper, P. F. [School of Mathematics and Statistics, University of Sheffield, Sheffield S3 7RH (United Kingdom); Pontin, D. I. [Division of Mathematics, University of Dundee, Dundee DD1 4HN (United Kingdom)

    2013-03-15T23:59:59.000Z

    We report here, for the first time, an observed instability of a Kelvin-Helmholtz nature occurring in a fully three-dimensional (3D) current-vortex sheet at the fan plane of a 3D magnetic null point. The current-vortex layer forms self-consistently in response to foot point driving around the spine lines of the null. The layer first becomes unstable at an intermediate distance from the null point, with the instability being characterized by a rippling of the fan surface and a filamentation of the current density and vorticity in the shear layer. Owing to the 3D geometry of the shear layer, a branching of the current filaments and vortices is observed. The instability results in a mixing of plasma between the two topologically distinct regions of magnetic flux on either side of the fan separatrix surface, as flux is reconnected across this surface. We make a preliminary investigation of the scaling of the system with the dissipation parameters. Our results indicate that the fan plane separatrix surface is an ideal candidate for the formation of current-vortex sheets in complex magnetic fields and, therefore, the enhanced heating and connectivity change associated with the instabilities of such layers.

  8. Single beam optical vortex tweezers with tunable orbital angular momentum

    SciTech Connect (OSTI)

    Gecevi?ius, Mindaugas; Drevinskas, Rokas, E-mail: rd1c12@orc.soton.ac.uk; Beresna, Martynas; Kazansky, Peter G. [Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2014-06-09T23:59:59.000Z

    We propose a single beam method for generating optical vortices with tunable optical angular momentum without altering the intensity distribution. With the initial polarization state varying from linear to circular, we gradually control the torque transferred to the trapped non-absorbing and non-birefringent silica beads. The continuous transition from the maximum rotation speed to zero without changing the trapping potential gives a way to study the complex tribological interactions.

  9. Lattice distortion and stripelike antiferromagnetic order in Ca10(Pt3As8)(Fe2As2)5

    SciTech Connect (OSTI)

    Sapkota, Aashish [Ames Laboratory; Tucker, Gregory S [Ames Laboratory; Ramazanoglu, Mehmet [Ames Laboratory; Tian, Wei [Ames Laboratory; Ni, N [University of California; Cava, R. J.; McQueeney, Robert J [Princeton; Goldman, Alan I [Ames Laboratory; Kreyssig, Andreas [Ames Laboratory

    2014-09-01T23:59:59.000Z

    Ca10(Pt3As8)(Fe2As2)5 is the parent compound for a class of Fe-based high-temperature superconductors where superconductivity with transition temperatures up to 30 K can be introduced by partial element substitution. We present a combined high-resolution high-energy x-ray diffraction and elastic neutron scattering study on a Ca10(Pt3As8)(Fe2As2)5 single crystal. This study reveals the microscopic nature of two distinct and continuous phase transitions to be very similar to other Fe-based high-temperature superconductors: an orthorhombic distortion of the high-temperature tetragonal Fe-As lattice below TS=110(2) K followed by stripelike antiferromagnetic ordering of the Fe moments below TN=96(2) K. These findings demonstrate that major features of the Fe-based high-temperature superconductors are very robust against variations in chemical constitution as well as structural imperfection of the layers separating the Fe-As layers from each other and confirms that the Fe-As layers primarily determine the physics in this class of material.

  10. Origin State Destination State

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    7. Estimated truck transportation rates for coal, state to state, EIA data Origin State Destination State 2008 2009 2010 2008-2010 2009-2010 Alabama Alabama W W W W W Alabama...

  11. Geometry and scaling of tangled vortex lines in three-dimensional random wave fields

    E-Print Network [OSTI]

    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.

  12. Interconversion of dark soliton and Josephson vortex in a quasi-1D long Bose Josephson junction

    E-Print Network [OSTI]

    V. M. Kaurov; A. B. Kuklov

    2004-06-15T23:59:59.000Z

    Dark soliton (DS) and Josephson vortex (JV) in quasi-1D long Bose Josephson junction (BJJ) can be interconverted by tuning Josephson coupling. Rates of the interconversion as well as of the thermally activated phase-slip effect, resulting in the JV switching its vorticity, have been evaluated. The role of quantum phase-slip in creating superposition of JVs with opposite vorticities as a qubit is discussed as well. Utilization of the JV for controlled and coherent transfer of atomic Bose-Einstein condensate (BEC) is suggested.

  13. Ground state lost but degeneracy found: the effective thermodynamics of artificial spin ice

    E-Print Network [OSTI]

    Cristiano Nisoli; R. F. Wang; Jie Li; William F. McConville; Paul E. Lammert; Peter Schiffer; Vincent H. Crespi

    2007-04-16T23:59:59.000Z

    We analyze the rotational demagnetization of artificial spin ice, a recently realized array of nanoscale single-domain ferromagnetic islands. Demagnetization does not anneal this model system into its anti-ferromagnetic ground state: the moments have a static disordered configuration similar to the frozen state of the spin ice materials. We demonstrate that this athermal system has an effective extensive degeneracy and we introduce a formalism that can predict the populations of local states in this ice-like system with no adjustable parameters.

  14. Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel beams

    SciTech Connect (OSTI)

    Wetzel, Benjamin, E-mail: benjamin.wetzel@femto-st.fr; Xie, Chen; Lacourt, Pierre-Ambroise; Dudley, John M.; Courvoisier, Francois [Département d'Optique P.M. Duffieux, Institut FEMTO-ST, UMR–6174 CNRS, Université de Franche-Comté, 25030 Besançon (France)] [Département d'Optique P.M. Duffieux, Institut FEMTO-ST, UMR–6174 CNRS, Université de Franche-Comté, 25030 Besançon (France)

    2013-12-09T23:59:59.000Z

    We report the fabrication of micro and nano-disks in single layer chemical vapor 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??m were characterized by spatially resolved micro-Raman spectroscopy. The variation of ablation threshold was investigated as a function of the number of pulses showing an incubation effect. A very high degree of size control of the fabricated graphene disks is enabled using a sequence of femtosecond pulses with different vortex orders.

  15. MAP, MAC, and Vortex-rings Configurations in the Weinberg-Salam Model

    E-Print Network [OSTI]

    Rosy Teh; Ban-Loong Ng; Khai-Ming Wong

    2014-08-20T23:59:59.000Z

    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 $\\pm\\frac{2\\pi n}{e}$ 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 value of Higgs boson mass $0\\leq M_H^2\\leq 80$ at Weinberg angle $\\theta_W=\\frac{\\pi}{4}$.

  16. Direct femtosecond laser ablation of copper with an optical vortex beam

    SciTech Connect (OSTI)

    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.

  17. Tracking Waves and Vortex Nucleation in Excitable Systems with Anomalous Dispersion N. Manz, C.T. Hamik, and O. Steinbock

    E-Print Network [OSTI]

    Steinbock, Oliver

    Tracking Waves and Vortex Nucleation in Excitable Systems with Anomalous Dispersion N. Manz, C obtained from a chemical reaction-diffusion system in which wave propagation is limited to a finite band of wavelengths and in which no solitary pulses exist. Wave patterns increase their size through repeated

  18. Direct observation of superconducting vortex clusters pinned by a periodic array of magnetic dots in ferromagnetic/superconducting hybrid structures

    E-Print Network [OSTI]

    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

  19. ccsd-00003161,version1-26Oct2004 Vortex patterns in a fast rotating Bose-Einstein condensate

    E-Print Network [OSTI]

    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

  20. Quantum Dissociation of a Vortex-Antivortex Pair in a Long Josephson Junction M.V. Fistul,1

    E-Print Network [OSTI]

    Wallraff, Andreas

    Quantum Dissociation of a Vortex-Antivortex Pair in a Long Josephson Junction M.V. Fistul,1 A VAV pair manifests itself in a switching of the Josephson junction from the superconducting biased single Josephson junctions (JJs), various SQUIDs, and small Josephson junction arrays, contain

  1. Quantum Hasimoto transformation and nonlinear waves on a superfluid vortex filament under the quantum local induction approximation

    E-Print Network [OSTI]

    Robert A. Van Gorder

    2014-11-19T23:59:59.000Z

    The Hasimoto transformation between the classical LIA (local induction approximation, a model approximating the motion of a thin vortex filament) and the nonlinear Schr\\"odinger equation (NLS) has proven very useful in the past, since it allows one to construct new solutions to the LIA once a solution to the NLS is known. In the present paper, the quantum form of the LIA (which includes mutual friction effects) is put into correspondence with a type of complex nonlinear dispersive partial differential equation (PDE) with cubic nonlinearity (similar in form to a Ginsburg-Landau equation, with additional nonlinear terms). Transforming the quantum LIA in such a way enables one to obtain quantum vortex filament solutions once solutions to this dispersive PDE are known. From our quantum Hasimoto transformation, we determine the form and behavior of Stokes waves and a standing 1-soliton solution under normal and binormal friction effects. The soliton solution on a quantum vortex filament is a natural generalization of the classical 1-soliton solution constructed mathematically by Hasimoto (which motivated subsequent real-world experiments). The quantum Hasimoto transformation is useful when normal fluid velocity is relatively weak, so for the case where the normal fluid velocity is dominant we resort to other approaches. We consider the dynamics of the tangent vector to the vortex filament directly from the quantum LIA, and this approach, while less elegant than the quantum Hasimoto transformation, enables us to study waves primarily driven by the normal fluid velocity.

  2. Magnetic Excitation Spectrum of the Square Lattice S=1/2 Heisenberg Antiferromagnet K2V3O8

    SciTech Connect (OSTI)

    Lumsden, Mark D [ORNL; Nagler, Stephen E [ORNL; Sales, Brian C [ORNL; Tennant, D. A. [ISIS Facility, Rutherford Appleton Laboratory; McMorrow, D. F. [Riso National Laboratory, Roskilde, Denmark; Lee, S.-H. [National Institute of Standards and Technology (NIST); Park, S. [National Institute of Standards and Technology (NIST)

    2006-01-01T23:59:59.000Z

    We have explored the magnetic excitation spectrum of the S=1/2 square lattice Heisenberg antiferromagnet, K{sub 2}V{sub 3}O{sub 8}, using both triple-axis and time-of-flight inelastic neutron scattering. The long-wavelength spin waves are consistent with the previously determined Hamiltonian for this material. A small energy gap of 72{+-}9 {micro}eV is observed at the antiferromagnetic zone center and the near-neighbor exchange constant is determined to be 1.08{+-}0.03 meV. A finite ferromagnetic interplanar coupling is observed along the crystallographic c axis with a magnitude of J{sub c}=-0.0036{+-}0.0006 meV. However, upon approaching the zone boundary, the observed excitation spectrum deviates significantly from the expectation of linear spin wave theory resulting in split modes at the ({pi}/2,{pi}/2) zone boundary point. The effects of magnon-phonon interaction, orbital degrees of freedom, multimagnon scattering, and dilution/site randomness are considered in the context of the mode splitting. Unfortunately, no fully satisfactory explanation of this phenomenon is found and further theoretical and experimental work is needed.

  3. Method for the detection of a magnetic field utilizing a magnetic vortex

    DOE Patents [OSTI]

    Novosad, Valentyn (Chicago, IL); Buchanan, Kristen (Batavia, IL)

    2010-04-13T23:59:59.000Z

    The determination of the strength of an in-plane magnetic field utilizing one or more magnetically-soft, ferromagnetic member, having a shape, size and material whereas a single magnetic vortex is formed at remanence in each ferromagnetic member. The preferred shape is a thin circle, or dot. Multiple ferromagnetic members can also be stacked on-top of each other and separated by a non-magnetic spacer. The resulting sensor is hysteresis free. The sensor's sensitivity, and magnetic saturation characteristics may be easily tuned by simply altering the material, size, shape, or a combination thereof to match the desired sensitivity and saturation characteristics. The sensor is self-resetting at remanence and therefore does not require any pinning techniques.

  4. Vortex precession frequency and its amplitude-dependent shift in cylindrical nanomagnets

    SciTech Connect (OSTI)

    Metlov, Konstantin L., E-mail: metlov@fti.dn.ua [Donetsk Institute for Physics and Technology NAS, Donetsk 83114 (Ukraine)

    2013-12-14T23:59:59.000Z

    Frequency of free magnetic vortex precession in circular soft ferromagnetic nano-cylinders (magnetic dots) of various sizes is an important parameter, used in design of spintronic devices (such as spin-torque microwave nano-oscillators) and characterization of magnetic nanostructures. Here, using a recently developed collective-variable approach to non-linear dynamics of magnetic textures in planar nano-magnets, this frequency and its amplitude-dependent shift are computed analytically and plotted for the full range of cylinder geometries. The frequency shift is positive in large planar dots, but becomes negative in smaller and more elongated ones. At certain dot dimensions, a zero frequency shift is realized, which can be important for enhancing frequency stability of magnetic nano-oscillators.

  5. Vortex Lattice Studies in CeCoIn? with H?c

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Das, P.; White, J. S.; Holmes, A. T.; Gerber, S.; Forgan, E. M.; Bianchi, A. D.; Kenzelmann, M.; Zolliker, M.; Gavilano, J. L.; Bauer, E. D.; Sarrao, J. L.; Petrovic, C.; Eskildsen, M. R.

    2012-02-01T23:59:59.000Z

    We present small angle neutron scattering studies of the vortex lattice (VL) in CeCoIn? with magnetic fields applied parallel (H) to the antinodal [100] and nodal [110] directions. For H II 100], a single VL orientation is observed, while a 90° reorientation transition is found for H II [110]. For both field orientations and VL configurations we find a distorted hexagonal VL with an anisotropy, ?=2.0±0.05. The VL form factor shows strong Pauli paramagnetic effects similar to what have previously been reported for H II [001]. At high fields, above which the upper critical field (Hc2) becomes a first-order transition, an increased disordering of the VL is observed.

  6. Rotational response of superconductors: magneto-rotational isomorphism and rotation-induced vortex lattice

    E-Print Network [OSTI]

    Egor Babaev; Boris Svistunov

    2014-03-03T23:59:59.000Z

    The analysis of nonclassical rotational response of superfluids and superconductors was performed by Onsager (in 1949) \\cite{Onsager} and London (in 1950) \\cite{London} and crucially advanced by Feynman (in 1955) \\cite{Feynman}. It was established that, in thermodynamic limit, neutral superfluids rotate by forming---without any threshold---a vortex lattice. In contrast, the rotation of superconductors at angular frequency ${\\bf \\Omega}$---supported by uniform magnetic field ${\\bf B}_L\\propto {\\bf \\Omega}$ due to surface currents---is of the rigid-body type (London Law). Here we show that, neglecting the centrifugal effects, the behavior of a rotating superconductor is identical to that of a superconductor placed in a uniform fictitious external magnetic filed $\\tilde{\\bf H}=- {\\bf B}_L$. In particular, the isomorphism immediately implies the existence of two critical rotational frequencies in type-2 superconductors.

  7. Cyclostrophic adjustment in swirling gas flows and the Ranque-Hilsch vortex tube effect

    SciTech Connect (OSTI)

    Kalashnik, M. V., E-mail: lingel@obninsk.com; Visheratin, K. N. [SPA Typhoon (Russian Federation)], E-mail: kvisher@typhoon.obninsk.ru

    2008-04-15T23:59:59.000Z

    A theoretical analysis of cyclostrophic adjustment is presented; i.e., adjustment to balance between pressure gradient and centrifugal force in axisymmetric flow of an inviscid gas is examined. The solution to the problem is represented as the sum of a time-independent (balanced) and time-dependent (wave) components. It is shown that the wave component of the flow in an unbounded domain decays with time, and the corresponding solution reduces to the balanced component. In a bounded domain, the balanced flow component exists against the background of undamped acoustic waves. It is found that the balanced flow is thermally stratified at Mach numbers close to unity, with a substantial decrease in gas temperature (to between -50 and -100 deg. C) in the axial region. This finding, combined with the results of special experiments, is used to explain the Ranque-Hilsch vortex tube effect.

  8. The ground state of the spin-1/2 kagomé lattice antiferromagnet : neutron scattering studies of the zinc-paratacamite mineral family

    E-Print Network [OSTI]

    Helton, Joel Strader

    2009-01-01T23:59:59.000Z

    The magnetic properties of the geometrically frustrated quantum magnets clinoatacamite, Cu2(OH)3Cl, and herbertsmithite, ZnCu3(OH)6Cl2, are studied by means of neutron scattering measurements as well as specific heat, ...

  9. Gapless Spin Liquid Ground State in the S 1=2 Vanadium Oxyfluoride Kagome Antiferromagnet NH42C7H14NV7O6F18

    E-Print Network [OSTI]

    Paris-Sud 11, Université de

    7H14N½V7O6F18 L. Clark,1 J. C. Orain,2 F. Bert,2 M. A. De Vries,1 F. H. Aidoudi,3 R. E. Morris,3 P, France (Received 12 February 2013; published 16 May 2013) The vanadium oxyfluoride ½NH42½C7H14N½V7O6F1842½C7H14N½V7O6F18 [dia- mmonium quinuclidinium vanadium(III,IV) oxyfluoride; DQVOF] [15

  10. Control of magnetic, nonmagnetic, and superconducting states in annealed Ca(Fe1?xCox)2As2

    SciTech Connect (OSTI)

    Ran, Sheng; Budko, Serguei L.; Straszheim, Warren E.; Soh, Jing-Han; Kim, Min Gyu; Kreyssig, Andreas; Goldman, Alan I.; Canfield, Paul C.

    2012-06-22T23:59:59.000Z

    We have grown single-crystal samples of Co substituted CaFe2As2 using an FeAs flux and systematically studied the effects of annealing/quenching temperature on the physical properties of these samples. Whereas the as-grown samples (quenched from 960 ?C) all enter the collapsed tetragonal phase upon cooling, annealing/quenching temperatures between 350 and 800 ?C can be used to tune the system to low-temperature antiferromagnetic/orthorhomic or superconducting states as well. The progression of the transition temperature versus annealing/quenching temperature (T-Tanneal) phase diagrams with increasing Co concentration shows that, by substituting Co, the antiferromagnetic/orthorhombic and the collapsed tetragonal phase lines are separated and bulk superconductivity is revealed. We established a 3D phase diagram with Co concentration and annealing/quenching temperature as two independent control parameters. At ambient pressure, for modest x and Tanneal values, the Ca(Fe1?xCox)2As2 system offers ready access to the salient low-temperature states associated with Fe-based superconductors: antiferromagnetic/orthorhombic, superconducting, and nonmagnetic/collapsed tetragonal.

  11. Control of magnetic, nonmagnetic, and superconducting states in annealed Ca(Fe1–xCox)?As?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ran, S.; Bud'ko, S. L.; Straszheim, W. E.; Soh, J.; Kim, M. G.; Kreyssig, A.; Goldman, A. I.; Canfield, P. C.

    2012-06-01T23:59:59.000Z

    We have grown single-crystal samples of Co substituted CaFe?As? using an FeAs flux and systematically studied the effects of annealing/quenching temperature on the physical properties of these samples. Whereas the as-grown samples (quenched from 960°C) all enter the collapsed tetragonal phase upon cooling, annealing/quenching temperatures between 350 and 800°C can be used to tune the system to low-temperature antiferromagnetic/orthorhomic or superconducting states as well. The progression of the transition temperature versus annealing/quenching temperature (T-Tanneal) phase diagrams with increasing Co concentration shows that, by substituting Co, the antiferromagnetic/orthorhombic and the collapsed tetragonal phase lines are separated and bulk superconductivity is revealed. We established a 3D phase diagram with Co concentration and annealing/quenching temperature as two independent control parameters. At ambient pressure, for modest x and Tanneal values, the Ca(Fe??xCox)?As? system offers ready access to the salient low-temperature states associated with Fe-based superconductors: antiferromagnetic/orthorhombic, superconducting, and nonmagnetic/collapsed tetragonal.

  12. VOLUME 75, NUMBER 5 P H Y S I C A L R E V I E W L E T T E R S 31 JULY 1995 Impurities in S 5 1 2 Heisenberg Antiferromagnetic Chains

    E-Print Network [OSTI]

    Eggert, Sebastian

    Gothenburg, Sweden 2 Canadian Institute for Advanced Research and Physics Department, University of British k becomes quite large near the antiferromagnetic wave vector, and exhibits much stronger temperature give rise to temperature and finite length dependent corrections with a characteristic power law

  13. A new unconventional antiferromagnet, Yb3Pt4 M.C. Bennett a,b,, P. Khalifah c,d

    E-Print Network [OSTI]

    Aronson, Meigan

    at the Neel temperature. The absence of analogous Fermi liquid behavior in the heat capacity and the magnetic from the excited states, which are fully occupied above $150 K. The heat capacity displays a large and temperature independent component below the Neel temperature. The heat capacity in the ordered state

  14. A model of the lateral line of fish for vortex sensing This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Mohseni, Kamran

    A model of the lateral line of fish for vortex sensing This article has been downloaded from.1088/1748-3182/7/3/036016 A model of the lateral line of fish for vortex sensing Zheng Ren1 and Kamran Mohseni1,2,3,4 1 Department.iop.org/BB/7/036016 Abstract In this paper, the lateral line trunk canal (LLTC) of a fish is modeled

  15. A survey of ideal fluid propeller theories and a study of the effects of aerodynamic propeller loading on trailing vortex induced velocity and thrust

    E-Print Network [OSTI]

    Kelley, Edward Madison

    2012-06-07T23:59:59.000Z

    A SURVEY OF IDEAL FLUID PRO~ THEORIES AND A STUIE OP THE EFFECTS OF AERODYNAMIC PRO~ LOADING ON TRAILING VORTEX INDUCED VELOCITY AND THRUST A Thesis EDWARD MADISON ~ Suhmitted to the Graduate College of Texas A&M University in Partial... fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1969 h'h, jor Suhgect: Mechanical Engineering A SURVEY OF IDEAL FLUID PROPELLEB THEORIES AND A STUDY OF THE EFFKTS OF AERODYKVGC PROPELLER LOADING ON TRAILING VORTEX INDUCED...

  16. Magnetically induced splitting of a giant vortex state in a mesoscopic superconducting disk D. S. Golubovi,1

    E-Print Network [OSTI]

    Moshchalkov, Victor V.

    , whose dimensions are comparable to the supercon- ducting coherence length T and the penetration depth.4 and 1 nm, respectively. The triangle is separated from the supercon- ducting disk by a 2-nm Si spacer

  17. Observational constraints on the tropospheric and near-surface winter signature of the Northern Hemisphere stratospheric polar vortex

    E-Print Network [OSTI]

    Graf, Hans-F.; Zanchettin, Davide; Timmreck, Claudia; Bittner, Matthias

    2014-03-07T23:59:59.000Z

    of the stratosphere by radiative 116 processes. The possibility that the polar vortex anomalies were themselves produced by 117 waves generated in the troposphere was acknowledged in most studies (e.g., Polvani and 118 Waugh, 2004; Gerber and Polvani, 2009... irradiance. Other such features, which will not be covered within the current study, are early 133 Siberian snowfall (Cohen et al. 2007), as well as North Pacific and Indian Ocean sea-surface 134 temperatures (Hurwitz et al., 2012; Fletcher and Kushner...

  18. Reconnections of Vortex Loops in the Superfluid Turbulent HeII. Rates of the Breakdown and Fusion processes

    E-Print Network [OSTI]

    Sergey K. Nemirovskii

    2005-05-18T23:59:59.000Z

    Kinetics of merging and breaking down vortex loops is the important part of the whole vortex tangle dynamics. Another part is the motion of individual lines, which obeys the Biot-Savart law in presence of friction force and of applied external velocity fields if any. In the present work we evaluate the coefficients of the reconnection rates $A(l_{1},l_{2},l)$ and $B(l,l_{1},l_{2})$. Quantity $A$ is a number (per unit of time and per unit of volume) of events, when two loops with lengths $l_{1}$and $l_{2}$ collide and form the single loop of length $ l=l_{1}+l_{2}$. Quantity $% B(l,l_{1},l_{2}) $ describes the rate of events, when the single loop of the length $l$ breaks down into two the daughter loops of lengths $ l_{1}$ and $l_{2}$. These quantities ave evaluated as the averaged numbers of zeroes of vector $\\mathbf{S}%_{s}(\\xi_{2},\\xi_{1},t)$ connecting two points on the loops of $\\xi_{2}$ and $ \\xi_{1}$ at moment of time $t$. Statistics of the individual loops is taken from the Gaussian model of vortex tangle. PACS-number 67.40

  19. Nanoscale strain-induced pair suppression as a source of vortex pinning in high-temperature superconductors

    SciTech Connect (OSTI)

    Llordes, A. [ICMAB, Barcelona, Spain; Palau, A. [ICMAB, Barcelona, Spain; Vlad, R. [ICMAB, Barcelona, Spain; Pomar, A. [ICMAB, Barcelona, Spain; Arbiol, Jordi [ICMAB, Barcelona, Spain; Guzman, Roger [ICMAB, Barcelona, Spain; Gazquez Alabart, Jaume [ORNL; Varela del Arco, Maria [ORNL; Sandiumenge, Felip [ICMAB, Barcelona, Spain; Ricart, Susagna [ICMAB, Barcelona, Spain; Puig, Teresa [ICMAB, Barcelona, Spain; 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; Deutscher, G. [Tel Aviv University; Moschalkov, V. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; 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 centres 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.

  20. Anomalous critical fields in quantum critical superconductors

    E-Print Network [OSTI]

    Putzke, C.; Walmsley, P.; Fletcher, J.D.; Malone, L.; Vignolles, D.; Proust, C.; Badoux, S.; See, P.; Beere, H.E.; Ritchie, D.A.; Kasahara, S.; Mizukami, Y.; Shibauchi, T.; Matsuda, Y.; Carrington, A.

    2015-01-01T23:59:59.000Z

    -temperature superconductivity. However, the exact mechanism by which this occurs remains poorly understood. The iron-pnictide superconductor BaFe2(As1?xPx)2 is perhaps the clearest example to date of a high temperature quantum critical superconductor, and so it is a... mixing of antiferromagnetism and superconductivity, suggesting that a highly unusual vortex state is realised in quantum critical superconductors. Quantum critical points (QCPs) can be associated with a variety of different order-disorder phenomena...

  1. Experimental optimization of a free vortex propeller runner for micro hydro application

    SciTech Connect (OSTI)

    Singh, Punit; Nestmann, Franz [Institute for Water and River Basin Management (IWG), University of Karlsruhe, Kaiser Str. 12, D 76128 Karlsruhe (Germany)

    2009-09-15T23:59:59.000Z

    The turbine technology for low head application in the micro hydro range has been vastly neglected despite niche available in scattered regions of valley flows as well as in wastewater canals and other energy recovery schemes, where the available head does not exceed 2 meters. The goal of this study is to develop hydraulically optimized propeller turbines for the micro hydro range with a particular focus on ease of manufacture. This paper presents a wide range of geometrical optimization steps carried out on a propeller runner, whose blades have been designed using the free vortex theory, and operating with a gross head from 1.5 to 2 m and discharge of approximately 75 l/s. It further illustrates 3 stages of geometrical modifications carried out on the runner with an objective of optimizing the runner performance. These modifications comprised of changes to the tip angles (both at the runner inlet and exit) as well as the hub angles (at the runner inlet) of the runner blades. The paper also presents an interesting theoretical methodology to analyze the effects of each optimization stage. This method looks at the relative changes to shaft power and discharge at constant head and speed and gives wonderful insight as to how the internal parameters like Euler shaft work and runner hydraulic losses are behaving with respect to each optimization stage. It was found that the performance of the runner was very sensitive to changes to exit tip angle. At two levels of modification, the discharge increased in the range of 15-30%, while shaft power increased in the range of 12-45%, thus influencing the efficiency characteristics. The results of the runner inlet tip modification were very interesting in that a very significant rise of turbine efficiency was recorded from 55% to 74% at the best efficiency point, which was caused by a reduced discharge consumption as well as a higher power generation. It was also found that the optimization study on a propeller runner has reasonably validated the estimates of the free vortex theory despite small deviations. The final runner configuration demonstrated a maximum efficiency of 74% ({+-}1.8%), which is very encouraging from the perspectives of micro hydro application. The paper concludes with recommendations of a series of optimization steps to increase the efficiency of the runner. It also recommends the attempt of Computational Fluid Dynamics both as a validation and optimization tool for future research on propeller runners. (author)

  2. Flame-vortex interaction driven combustion dynamics in a backward-facing step combustor

    SciTech Connect (OSTI)

    Altay, H. Murat; Speth, Raymond L.; Hudgins, Duane E.; Ghoniem, Ahmed F. [Massachusetts Institute of Technology, Department of Mechanical Engineering, Cambridge, MA 02139 (United States)

    2009-05-15T23:59:59.000Z

    The combustion dynamics of propane-hydrogen mixtures are investigated in an atmospheric pressure, lean, premixed backward-facing step combustor. We systematically vary the equivalence ratio, inlet temperature and fuel composition to determine the stability map of the combustor. Simultaneous pressure, velocity, heat release rate and equivalence ratio measurements and high-speed video from the experiments are used to identify and characterize several distinct operating modes. When fuel is injected far upstream from the step, the equivalence ratio entering the flame is temporally and spatially uniform, and the combustion dynamics are governed only by flame-vortex interactions. Four distinct dynamic regimes are observed depending on the operating parameters. At high but lean equivalence ratios, the flame is unstable and oscillates strongly as it is wrapped around the large unsteady wake vortex. At intermediate equivalence ratios, weakly oscillating quasi-stable flames are observed. Near the lean blowout limit, long stable flames extending from the corner of the step are formed. At atmospheric inlet temperature, the unstable mode resonates at the 1/4 wavemode of the combustor. As the inlet temperature is increased, the 5/4 wavemode of the combustor is excited at high but lean equivalence ratios, forming the high-frequency unstable flames. Higher hydrogen concentration in the fuel and higher inlet temperatures reduce the equivalence ratios at which the transitions between regimes are observed. We plot combustion dynamics maps or the response curves, that is the overall sound pressure level as a function of the equivalence ratio, for different operating conditions. We demonstrate that numerical results of strained premixed flames can be used to collapse the response curves describing the transitions among the dynamic modes onto a function of the heat release rate parameter alone, rather than a function dependent on the equivalence ratio, inlet temperature and fuel composition separately. We formulate a theory for predicting the critical values of the heat release parameter at which quasi-stable to unstable and unstable to high-frequency unstable modes take place. (author)

  3. Vortex Diode Analysis and Testing for Fluoride Salt-Cooled High-Temperature Reactors

    SciTech Connect (OSTI)

    Yoder Jr, Graydon L [ORNL; Elkassabgi, Yousri M. [Texas A& M University, Kingsville; De Leon, Gerardo I. [Texas A& M University, Kingsville; Fetterly, Caitlin N. [Texas A& M University, Kingsville; Ramos, Jorge A. [Texas A& M University, Kingsville; Cunningham, Richard Burns [University of Tennessee, Knoxville (UTK)

    2012-02-01T23:59:59.000Z

    Fluidic diodes are presently being considered for use in several fluoride salt-cooled high-temperature reactor designs. A fluidic diode is a passive device that acts as a leaky check valve. These devices are installed in emergency heat removal systems that are designed to passively remove reactor decay heat using natural circulation. The direct reactor auxiliary cooling system (DRACS) uses DRACS salt-to-salt heat exchangers (DHXs) that operate in a path parallel to the core flow. Because of this geometry, under normal operating conditions some flow bypasses the core and flows through the DHX. A flow diode, operating in reverse direction, is-used to minimize this flow when the primary coolant pumps are in operation, while allowing forward flow through the DHX under natural circulation conditions. The DRACSs reject the core decay heat to the environment under loss-of-flow accident conditions and as such are a reactor safety feature. Fluidic diodes have not previously been used in an operating reactor system, and therefore their characteristics must be quantified to ensure successful operation. This report parametrically examines multiple design parameters of a vortex-type fluidic diode to determine the size of diode needed to reject a particular amount of decay heat. Additional calculations were performed to size a scaled diode that could be tested in the Oak Ridge National Laboratory Liquid Salt Flow Loop. These parametric studies have shown that a 152.4 mm diode could be used as a test article in that facility. A design for this diode is developed, and changes to the loop that will be necessary to test the diode are discussed. Initial testing of a scaled flow diode has been carried out in a water loop. The 150 mm diode design discussed above was modified to improve performance, and the final design tested was a 171.45 mm diameter vortex diode. The results of this testing indicate that diodicities of about 20 can be obtained for diodes of this size. Experimental results show similar trends as the computational fluid dynamics (CFD) results presented in this report; however, some differences exist that will need to be assessed in future studies. The results of this testing will be used to improve the diode design to be tested in the liquid salt loop system.

  4. The effect of disorder on the critical points in the vortex phase diagram of YBCO

    SciTech Connect (OSTI)

    Crabtree, G. W.; Kwok, W. K.; Paulius, L. M.; Petrean, A. M.; Olsson, R. J.; Karapetrov, G.; Tobos, V.; Moulton, W. G.

    2000-01-19T23:59:59.000Z

    The effect of line disorder induced by heavy ion irradiation and of point disorder induced by proton and electron irradiation on the upper and lower critical points in the vortex phase diagram of YBCO is presented. The authors find that dilute line disorder induces a Bose glass transition at low fields which is replaced at the lower critical point by first order melting at higher fields. Strong pinning point defects raise the lower critical point, while weak pinning point defects have little or no effect on the lower critical point. The upper critical point is lowered by point disorder, but raised by line disorder. First order melting is suppressed by point disorder in two ways, by lowering of the upper critical point only for weak point pins, or by merging of the upper and lower critical points for strong point pins. The differing responses of the upper and lower critical points to line and point disorder can be understood in a picture of transverse and longitudinal spatial fluctuations.

  5. Development of a vortex combustor (VC) for space/water heating applications (combustion tests). Final report

    SciTech Connect (OSTI)

    Fu, T.T. [Naval Civil Engineering Lab., Port Hueneme, CA (United States); Nieh, S. [Catholic Univ. of America, Washington, DC (United States). Combustion and Multiphase Flows Lab.

    1990-11-01T23:59:59.000Z

    This is the final report for Interagency Agreement DE-AI22-87PC79660 on ``Combustion Test`` for vortex combustor (VC) development for commercial applications. The work culminated in the successful demonstration of a 2 MB/H proof-of-concept (POC) model firing coal-water fuel (CWF). This development is concerned with a new concept in combustion, and was a general lack of relevant information. The work therefore began (in addition to the companion cold flow modeling study) with the design and test of two subscale models (0.15 and 0.3 MB/H) and one full scale model (3 MB/H) to obtain the needed information. With the experience gained, the 2 MB/H POC model was then designed and demonstrated. Although, these models were designed somewhat differently from one another, they all performed well and demonstrated the superiority of the concept. In summary, test results have shown that VC can be fired on several coal fuels (CWF, dry ultrafine coal, utility grind pulverized coal) at high combustion efficiency (>99%), high firing intensity (up to 0.44 MB/H-ft{sup 3}), and at temperatures sufficiently low or dry ash removal. The combustion process is completed totally inside the combustor. Conventional combustion enhancement techniques such as: preheating (air and/or fuel), pre-combustion, and post combustion are not needed.

  6. Development of a vortex combustor (VC) for space/water heating applications (combustion tests)

    SciTech Connect (OSTI)

    Fu, T.T. (Naval Civil Engineering Lab., Port Hueneme, CA (United States)); Nieh, S. (Catholic Univ. of America, Washington, DC (United States). Combustion and Multiphase Flows Lab.)

    1990-11-01T23:59:59.000Z

    This is the final report for Interagency Agreement DE-AI22-87PC79660 on Combustion Test'' for vortex combustor (VC) development for commercial applications. The work culminated in the successful demonstration of a 2 MB/H proof-of-concept (POC) model firing coal-water fuel (CWF). This development is concerned with a new concept in combustion, and was a general lack of relevant information. The work therefore began (in addition to the companion cold flow modeling study) with the design and test of two subscale models (0.15 and 0.3 MB/H) and one full scale model (3 MB/H) to obtain the needed information. With the experience gained, the 2 MB/H POC model was then designed and demonstrated. Although, these models were designed somewhat differently from one another, they all performed well and demonstrated the superiority of the concept. In summary, test results have shown that VC can be fired on several coal fuels (CWF, dry ultrafine coal, utility grind pulverized coal) at high combustion efficiency (>99%), high firing intensity (up to 0.44 MB/H-ft[sup 3]), and at temperatures sufficiently low or dry ash removal. The combustion process is completed totally inside the combustor. Conventional combustion enhancement techniques such as: preheating (air and/or fuel), pre-combustion, and post combustion are not needed.

  7. Simulating local measurements on a quantum many body system with stochastic matrix product states

    E-Print Network [OSTI]

    Søren Gammelmark; Klaus Mølmer

    2009-11-25T23:59:59.000Z

    We demonstrate how to simulate both discrete and continuous stochastic evolution of a quantum many body system subject to measurements using matrix product states. A particular, but generally applicable, measurement model is analyzed and a simple representation in terms of matrix product operators is found. The technique is exemplified by numerical simulations of the anti-ferromagnetic Heisenberg spin-chain model subject to various instances of the measurement model. In particular we focus on local measurements with small support and non-local measurements which induces long range correlations.

  8. Smooth double critical state theory for type-II superconductors

    E-Print Network [OSTI]

    H. S. Ruiz; A. Bad\\'\\ia-Majós

    2010-05-30T23:59:59.000Z

    Several aspects of the general theory for the critical states of a vortex lattice and the magnetic flux dynamics in type-II superconductors are examined by a direct variational optimisation method and widespread physical principles. Our method allows to unify a number of conventional models describing the complex vortex configurations in the critical state regime. Special attention is given to the discussion of the relation between the flux-line cutting mechanism and the depinning threshold limitation. This is done by using a smooth double critical state concept which incorporates the so-called isotropic, elliptical, T and CT models as well-defined limits of our general treatment. Starting from different initial configurations for a superconducting slab in a 3D magnetic field, we show that the predictions of the theory range from the collapse to zero of transverse magnetic moments in the isotropic model, to nearly force free configurations in which paramagnetic values can arbitrarily increase with the applied field for magnetically anisotropic current voltage laws. Noteworthily, the differences between the several model predictions are minimal for the low applied field regime.

  9. Synthesis, structure and magnetic properties of La{sub 3}Co{sub 2}SbO{sub 9}: A double perovskite with competing antiferromagnetic and ferromagnetic interactions

    SciTech Connect (OSTI)

    Franco, D.G.; Fuertes, V.C.; Blanco, M.C. [INFIQC (CONICET), Departamento de Fisicoquimica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina)] [INFIQC (CONICET), Departamento de Fisicoquimica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina); Fernandez-Diaz, M.T. [Institute Laue-Langevin (ILL) 156X, F-38042 Grenoble Cedex 9 (France)] [Institute Laue-Langevin (ILL) 156X, F-38042 Grenoble Cedex 9 (France); Sanchez, R.D., E-mail: rodo@cab.cnea.gov.ar [Centro Atomico Bariloche, CNEA and Instituto Balseiro, Universidad Nacional de Cuyo, Av. Bustillo 9500, 8400 Rio Negro (Argentina); Carbonio, R.E., E-mail: carbonio@fcq.unc.edu.ar [INFIQC (CONICET), Departamento de Fisicoquimica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina)

    2012-10-15T23:59:59.000Z

    The synthesis, structural characterization, and magnetic properties of La{sub 3}Co{sub 2}SbO{sub 9} double perovskite are reported. The crystal structure has been refined by X-ray and neutron powder diffraction data in the monoclinic space group P2{sub 1}/n. Co{sup 2+} and Sb{sup 5+} have the maximum order allowed for the La{sub 3}Co{sub 2}SbO{sub 9} stoichiometry. Rietveld refinements of powder neutron diffraction data show that at room temperature the cell parameters are a=5.6274(2) A, b=5.6842(2) A, c=7.9748(2) A and {beta}=89.999(3) Degree-Sign . Magnetization measurements indicate the presence of ferromagnetic correlations with T{sub C}=55 K attributed to the exchange interactions for non-linear Co{sup 2+}-O-Sb{sup 5+}-O-Co{sup 2+} paths. The effective magnetic moment obtained experimentally is {mu}{sub exp}=4.38 {mu}{sub B} (per mol Co{sup 2+}), between the theoretical one for spin only (3.87 {mu}{sub B}) and spin-orbit value (6.63 {mu}{sub B}), indicating partially unquenched contribution. The low magnetization value at high magnetic field and low temperature (1 {mu}{sub B}/f.u., 5 T and 5 K) and the difference between ZFC and FC magnetization curves (at 5 kOe) indicate that the ferromagnetism do not reach a long range order and that the material has an important magnetic frustration. - Graphical abstract: Co-O-Co (Yellow octahedra only) rich zones (antiferromagnetic) are in contact with Co-O-Sb-O-Co (Red and yellow octahedra) rich zones (Ferromagnetic) to give the peculiar magnetic properties, as a consequence, a complex hysteresis loop can be observed composed by a main and irreversible curve in all the measured range, superimposed with a ferromagnetic component at low fields. Highlights: Black-Right-Pointing-Pointer La{sub 3}Co{sub 2}SbO{sub 9} has small Goldschmidt Tolerance Factor (t) due to the small size of La{sup 3+}. Black-Right-Pointing-Pointer Small t determines an angle for the path Co{sup 2+}-O-Sb{sup 5+}-O-Co{sup 2+} of 153 Degree-Sign . Black-Right-Pointing-Pointer Ferromagnetism is attributed to exchange interactions for Co{sup 2+}-O-Sb{sup 5+}-O-Co{sup 2+} paths. Black-Right-Pointing-Pointer Ferromagnetic nanoclusters are embedded in an antiferromagnetic matrix.

  10. Effects of coexisting spin disorder and antiferromagnetism on the magnetic behavior of nanostructured (Fe{sub 79}Mn{sub 21}){sub 1?x}Cu{sub x} alloys

    SciTech Connect (OSTI)

    Mizrahi, M., E-mail: mizrahi@fisica.unlp.edu.ar, E-mail: cabrera@fisica.unlp.edu.ar [INIFTA-CCT- La Plata-CONICET and Departamento de Física, Facultad de Ciencias Exactas, C. C. 67, Universidad Nacional de La Plata, 1900 La Plata (Argentina); Cabrera, A. F., E-mail: mizrahi@fisica.unlp.edu.ar, E-mail: cabrera@fisica.unlp.edu.ar; Desimoni, J. [IFLP-CCT-La Plata-CONICET and Departamento de Física, Facultad de Ciencias Exactas C.C. 67, Universidad Nacional de La Plata, 1900 La Plata (Argentina); Stewart, S. J. [IFLP-CCT-La Plata-CONICET and Departamento de Física, Facultad de Ciencias Exactas C.C. 67, Universidad Nacional de La Plata, 1900 La Plata (Argentina); Instituto Ciencias de la Salud, Universidad Nacional Arturo Jauretche, Av. Calchaquí No. 6200, Florencio Varela (Argentina)

    2014-06-07T23:59:59.000Z

    We report a magnetic study on nanostructured (Fe{sub 79}Mn{sub 21}){sub 1?x}Cu{sub x} (0.00???x???0.30) alloys using static magnetic measurements. The alloys are mainly composed by an antiferromagnetic fcc phase and a disordered region that displays a spin-glass-like behavior. The interplay between the antiferromagnetic and magnetically disordered phases establishes an exchange anisotropy that gives rise to a loop shift at temperatures below the freezing temperature of moments belonging to the disordered region. The loop shift is more noticeable as the Cu content increases, which also enhances the spin-glass-like features. Further, in the x?=?0.30 alloy the alignment imposed by applied magnetic fields higher than 4 kOe prevail over the configuration determined by the frustration mechanism that characterizes the spin glass-like phase.

  11. Antiferromagnetic ordering in a novel five-connected 3D polymer {Cu2(2,5-Me2pyz)[N(CN)2]4}nn (2,5-Me2pyz=2,5-dimethylpyrazine)y

    E-Print Network [OSTI]

    Gao, Song

    D interpenetrating network and a b-form with a 2D sheet structure.9 These polymers, however, exhibit networks. It is also a two-fold interpenetrated network (Fig. 2) that is closely related to a recentlyAntiferromagnetic ordering in a novel five-connected 3D polymer {Cu2(2,5-Me2pyz)[N(CN)2]4}nn (2

  12. JOURNAL DE PHYSIQUE CoZZoque C9, suppZ6ment au noll, Tome 41, novembre 1980, page C9-423 EXPERIMENTAL STUDY OF A FREE-VORTEX AERODYNAMIC WINDOW

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -423 EXPERIMENTAL STUDY OF A FREE-VORTEX AERODYNAMIC WINDOW W. Masuda and M. Yuasa Research Institute, Ishikawajima free-vortex aerodynamic window has been fabricated and tested. Aerodynamic performance studies show of solid materials, an aerodynamic window makes use of a nonabsorbing gas jet to permit the extraction

  13. Heat Transfer Enhancement for Finned-Tube Heat Exchangers with Vortex Generators: Experimental and Numerical Results

    SciTech Connect (OSTI)

    O'Brien, James Edward; Sohal, Manohar Singh; Huff, George Albert

    2002-08-01T23:59:59.000Z

    A combined experimental and numerical investigation is under way to investigate heat transfer enhancement techniques that may be applicable to large-scale air-cooled condensers such as those used in geothermal power applications. The research is focused on whether air-side heat transfer can be improved through the use of finsurface vortex generators (winglets,) while maintaining low heat exchanger pressure drop. A transient heat transfer visualization and measurement technique has been employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements have also been acquired in a separate multiple-tube row apparatus. In addition, numerical modeling techniques have been developed to allow prediction of local and average heat transfer for these low-Reynolds-number flows with and without winglets. Representative experimental and numerical results presented in this paper reveal quantitative details of local fin-surface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. The winglets were triangular (delta) with a 1:2 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface Nusselt-number results indicate a significant level of heat transfer enhancement (average enhancement ratio 35%) associated with the deployment of the winglets with oval tubes. Pressure drop measurements have also been obtained for a variety of tube and winglet configurations using a single-channel flow apparatus that includes four tube rows in a staggered array. Comparisons of heat transfer and pressure drop results for the elliptical tube versus a circular tube with and without winglets are provided. Heat transfer and pressure-drop results have been obtained for flow Reynolds numbers based on channel height and mean flow velocity ranging from 700 to 6500.

  14. Magnetic structure and domain conversion of the quasi-2D frustrated antiferromagnet CuCrO{sub 2} probed by NMR

    SciTech Connect (OSTI)

    Sakhratov, Yu. A. [National High Magnetic Field Laboratory (United States); Svistov, L. E., E-mail: svistov@kapitza.ras.ru [Russian Academy Sciences, Kapitza Institute for Physical Problems (Russian Federation); Kuhns, P. L.; Zhou, H. D.; Reyes, A. P. [National High Magnetic Field Laboratory (United States)

    2014-11-15T23:59:59.000Z

    We have carried out {sup 63,65}Cu NMR spectra measurements in a magnetic field up to about 15.5 T on a single crystal of the multiferroic triangular-lattice antiferromagnet CuCrO{sub 2}. The measurements were performed for perpendicular and parallel orientations of the magnetic field with respect to the c axis of the crystal, and the detailed angle dependence of the spectra on the magnetic field direction in the ab plane was studied. The shape of the spectra can be well described in the model of spiral spin structure proposed by recent neutron diffraction experiments. When the field is rotated perpendicular to the crystal c axis, we observed, directly for the first time, a remarkable reorientation of the spin plane simultaneous with rotation of the incommensurate wavevector, by quantitatively deducing the conversion of the energetically less favorable domain to a more favorable one. At high enough fields parallel to the c axis, the data are consistent with either a field-induced commensurate spiral magnetic structure or an incommensurate spiral magnetic structure with a disorder in the c direction, suggesting that high fields may have influence on interplanar ordering.

  15. Crystal structure and antiferromagnetic ordering of quasi-2D [Cu(HF{sub 2})(pyz){sub 2}]TaF{sub 6} (pyz = pyrazine).

    SciTech Connect (OSTI)

    Manson, J. L.; Schlueter, J. A.; McDonald, R. D.; Singleton, J.; Materials Science Division; Eastern Washington Univ.; LANL

    2010-04-01T23:59:59.000Z

    The crystal structure of the title compound was determined by X-ray diffraction at 90 and 295 K. Copper(II) ions are coordinated to four bridging pyz ligands to form square layers in the ab-plane. Bridging HF{sub 2}{sup -} ligands join the layers together along the c-axis to afford a tetragonal, three-dimensional (3D) framework that contains Taf{sub 6}{sup -} anions in every cavity. At 295 K, the pyz rings lie exactly perpendicular to the layers and cooling to 90 K induces a canting of those rings. Magnetically, the compound exhibits 2D antiferromagnetic correlations within the 2D layers with an exchange interaction of -13.1(1) K. Weak interlayer interactions, as mediated by Cu-F-H-F-Cu, leads to long-range magnetic order below 4.2 K. Pulsed-field magnetization data at 0.5 K show a concave curvature with increasing B and reveal a saturation magnetization at 35.4 T.

  16. An experimental investigation of the rolling moment on a flat plate in the presence of a free vortex of known strength

    E-Print Network [OSTI]

    Van Dusen, Maurice Verne

    2012-06-07T23:59:59.000Z

    AN EXPERIMENTAL 1NVES1'IGATION OF THE ROLLING MOMENT ON A ILAT PLATE IN THE ?RESENCE OP A FREE VORTEX OF KNOWN STRENGTH A Thesis by MAURICE VERNE VAN DUSEN, JR. Submitted to the Graduate College of Teras A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE May 1970 Major Subject: Aerospace Engineering EXPERIMENTAL INVESTIGATION OF THE ROLLING MOMENT ON A FLAT PLATE IN THE PRESENCE OF A FREE VORTEX OF KNONN STRENGTH A Thesis by MAURICE VERNE VAN DUSEN, JR...

  17. Extremality of translation-invariant phases for a finite-state SOS-model on the binary tree

    E-Print Network [OSTI]

    C. Kuelske; U. A. Rozikov

    2014-11-21T23:59:59.000Z

    We consider the SOS (solid-on-solid) model, with spin values $0,1,2$, on the Cayley tree of order two (binary tree). We treat both ferromagnetic and antiferromagnetic coupling, with interactions which are proportional to the absolute value of the spin differences. We present a classification of all translation-invariant phases (splitting Gibbs measures) of the model: We show uniqueness in the case of antiferromagnetic interactions, and existence of up to seven phases in the case of ferromagnetic interactions, where the number of phases depends on the interaction strength. Next we investigate whether these states are extremal or non-extremal in the set of all Gibbs measures, when the coupling strength is varied, whenever they exist. We show that two states are always extremal, two states are always non-extremal, while three of the seven states make transitions between extremality and non-extremality. We provide explicit bounds on those transition values, making use of algebraic properties of the models, and an adaptation of the method of Martinelli, Sinclair, Weitz.

  18. Dipole-Induced Vortex Ratchets in Superconducting Films with Arrays of Micromagnets C. C. de Souza Silva,1,2,* A. V. Silhanek,1

    E-Print Network [OSTI]

    Moshchalkov, Victor V.

    Dipole-Induced Vortex Ratchets in Superconducting Films with Arrays of Micromagnets C. C. de Souza. By carrying out transport measurements with ac drive, we observed experimentally a recently predicted ratchet on the phenomenon known as ratchet effect [8]. As recently proposed by Carneiro [9], a different way to create

  19. Nonlinear propagation of dust-acoustic waves in an unmagnetized dusty plasma with nonthermal electron and vortex-like ion distribution

    SciTech Connect (OSTI)

    Paul, A.; Mandal, G.; Amin, M. R. [Department of Electronics and Communications Engineering, East West University, Aftabnagar, Dhaka 1212 (Bangladesh)] [Department of Electronics and Communications Engineering, East West University, Aftabnagar, Dhaka 1212 (Bangladesh); Mamun, A. A. [Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh)] [Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh)

    2013-10-15T23:59:59.000Z

    The nonlinear propagation of dust-acoustic (DA) waves in an unmagnetized dusty plasma consisting of nonthermal electrons, vortex-like (trapped) distributed ions and mobile negative dust have been investigated by employing the reductive perturbation technique. The effects of nonthermal electrons and trapped ions are found to modify the properties of the DA solitary waves.

  20. Characterization of the antiferromagnetism in Ag(pyz)2(S2O8) with a two-dimensional square lattice of Ag 2+ ions (Ag=silver, Pyz-pyrdzine, S2O8=sulfate)

    SciTech Connect (OSTI)

    Singleton, John [Los Alamos National Laboratory; Mc Donald, R [Los Alamos National Laboratory; Sengupta, P [Los Alamos National Laboratory; Cox, S [Los Alamos National Laboratory; Manson, J [E WASHINGTON U; Southerland, H [E WASHINGTON U; Warter, M [E WASHINGTON U; Stone, K [STATE UNIV OF NY; Stephens, P [STATE UNIV OF NY; Lancaster, T [OXFORD U; Steele, A [OXFORD U; Blundell, S [OXFORD U; Baker, P [OXFORD U; Pratt, F [RUTHERFORD-APPLETON LAB; Lee, C [NCSU; Whangbo, M [NCSU

    2009-01-01T23:59:59.000Z

    X-ray powder diffraction and magnetic susceptibility measurements show that Ag(pyz){sub 2}(S{sub 2}O{sub 8}) consists of 2D square nets of Ag{sup 2+} ions resulting from the corner-sharing of axially elongated AgN{sub 4}O{sub 2} octahedra and exhibits characteristic 2D antiferromagnetism. Nevertheless, {mu}{sup +}Sr measurements indicate that Ag(pyz){sub 2}(S{sub 2}O{sub 8}) undergoes 3D magnetic ordering below 7.8(3) K.

  1. Conjugation and transformation of the wave front by stimulated Brillouin scattering of vortex Laguerre - Gaussian laser modes

    SciTech Connect (OSTI)

    Kopalkin, A V; Bogachev, V A; Dolgopolov, Yu V; Kochemasov, G G; Kulikov, S M; Maslov, N V; Starikov, F A; Sukharev, Stanislav A; Feoktistov, V V; Bagdasarov, V Kh; Denisov, N N; Malyutin, A A

    2011-11-30T23:59:59.000Z

    We study experimentally stimulated Brilluoin scattering (SBS) of vortex laser beams, namely, the LG{sub 1}{sup 1} and LG{sub 0}{sup 1} Laguerre -Gaussian modes. The wave front transformation is experimentally demonstrated in the case of SBS of the LG{sub 1}{sup 1} laser mode, directly focused into the SBS cell, when the fundamental Gaussian mode LG{sub 0}{sup 0} rather than the conjugate mode is selected from the Stokes beam. It is shown that optical vortices become phase conjugate by destroying the laser mode structure in the SBS cell. Phase conjugation (PC) of the LG{sub 0}{sup 1} and LG{sub 1}{sup 1} modes is obtained in the SBS mirror using a regular aberrator (microlens raster) in the system of laser beam focusing into the SBS cell.

  2. Combustion of pulverized coal in vortex structures. Quarterly progress report No. 1, October 1, 1993--December 31, 1993

    SciTech Connect (OSTI)

    Gollahalli, S.R.

    1994-01-01T23:59:59.000Z

    The overall objectives of the project are: to investigate the changes in the characteristics of large scale vortex structures in the shear layer caused by the introduction of inert solid particles in one of the feed streams; to understand the effects of pyrolyzing solids on the shear layer behavior; to study the effect of combustion of the pyrolysis products on the shear layer structure, heat release rate, and pollutant emission characteristics; and to study the effect of modifying the shear layer characteristics on the ensuing flame behavior. The specific objectives for the first quarter were: to update the literature survey, to design and fabrication of the two-dimensional nozzle, and to modify the combustion chamber facility already existing in the lab to accommodate the nozzle constructed.

  3. The time evolution of a vortex-flame interaction observed via planar imaging of CH and OH

    SciTech Connect (OSTI)

    Nguyen, Quang-Viet; Paul, P.H.

    1996-05-01T23:59:59.000Z

    Planar laser-induced fluorescence imaging diagnostics of OH and CH are used to examine a premixed laminar flame subjected to a strong line-vortex pair. Results are reported for a fuel-rcih lamiar CH{sub 4}-air-N{sub 2} rod-stabilized flame. The flow studied was highly reproducible, which enabled the use of phase-sampled imaging to provide time-resolved image sequences. Image sequences are shown for a condition sufficient to produce localized extinction of the primary flame. Results indicate that a breakage in the CH front is not preceded by any distinct change in the OH front. The structure of the CH and OH profiles during the transient leading up to, and through the breakage of the CH front do not appear to be consistent with the concept of a strained laminar flame.

  4. The influence of current collectors on Tayler instability and electro-vortex flows in liquid metal batteries

    E-Print Network [OSTI]

    Weber, N; Priede, J; Stefani, F; Weier, T

    2014-01-01T23:59:59.000Z

    The Tayler instability is a kink-type flow instability which occurs when the electrical current through a conducting fluid exceeds a certain critical value. Originally studied in the astrophysical context, the instability was recently shown to be also a limiting factor for the upward scalability of liquid metal batteries. In this paper, we continue our efforts to simulate this instability for liquid metals within the framework of an integro-differential equation approach. The original solver is enhanced by multi-domain support with Dirichlet-Neumann partitioning for the static boundaries. Particular focus is laid on the detailed influence of the axial electrical boundary conditions on the characteristic features of the Tayler instability, and, secondly, on the occurrence of electro-vortex flows and their relevance for liquid metal batteries.

  5. Model for characterization of a vortex pair formed by shock passage over a light-gas inhomogeneity

    SciTech Connect (OSTI)

    Yang, J.; Kubota, T.; Zukoski, E.E. [California Inst of Technology, Pasadena, CA (United States)

    1994-01-01T23:59:59.000Z

    This work investigates the two-dimensional flow of a shock wave over a circular light-gas inhomogeneity in a channel with finite width. The pressure gradient from the shock wave interacts with the density gradient at the edge of the inhomogeneity to deposit vorticity around the perimeter, and the structure rolls up into a pair of counter-rotating vortices. The aim of this study is to develop an understanding of the scaling laws for the flow field produced by this interaction at times long after the passage of the shock across the inhomogeneity. Numerical simulations are performed for various initial conditions and the results are used to guide the development of relatively simple algebraic models that characterize the dynamics of the vortex pair, and that allow extrapolation of the numerical results to conditions more nearly of interest in practical situations. The models are not derived directly from the equations of motion but depend on these equations and on intuition guided by the numerical results. Agreement between simulations and models is generally good except for a vortex-spacing model which is less satisfactory. A practical application of this shock-induced vortical flow is rapid and efficient mixing of fuel and oxidizer in a SCRAMJET combustion chamber. One possible injector design uses the interaction of an oblique shock wave with a jet of light fuel to generate vorticity which stirs and mixes the two fluids and lifts the burning jet away from the combustor wall. Marble proposed an analogy between this three-dimensional steady flow and the two-dimensional unsteady problem of the present investigation. Comparison is made between closely corresponding three-dimensional steady and two-dimensional unsteady flows, and a mathematical description of Marble`s analogy is proposed. 17 refs.

  6. Exact Near-Onset Analysis of the Spin-Density-Wave Instability in Ferromagnetic Superconductors - the Linearly Polarized State

    E-Print Network [OSTI]

    Hu, Chia-Ren.

    1984-01-01T23:59:59.000Z

    PHYSICAL REVIEW 8 VOLUME 30, NUMBER 5 1 SEPTEMBER 1984 Exact near-onset analysis of the spin-density-wave instability in ferromagnetic superconductors: The linearly polarized state Chia-Ren Hu Department ofPhysics, Texas Ad'cM Uniuersity..., College Station, Texas 77843 (Received 29 August 1983) Using an approach similar to Abvikosov's theory of the vortex state near H, 2, we have performed an exact, near-onset analysis of a spin-density-wave instability leading to the "linearly polarized...

  7. Theoretical susceptibilities of linear antiferromagnets

    E-Print Network [OSTI]

    McSwain, Sulane

    1968-01-01T23:59:59.000Z

    . TABLE OF CONTENTS CHAPTER I. INTRODUCTION II. THEORY AND APPLICATIONS A. Manganese(II) Chloride B. Iron(II) Chloride C. Cobalt(II) Chloride D. Nickel(II) Chloride E. Copper(II) Chloride F. Manganese(II) Squarate Dihydrate G. Iron(II) Squarate... Dihydrate H. Cobalt(II) Squarate Dihydrate I. Nickel(II) Squarate Dihydrate III. DISCUSSION IV. EXPERIMENTAL Page 12 15 18 20 26 29 52 54 57 APPENDIX A. Synthesis of Transition Metal Squarates. . . . . . . . . . . . . . 45 B. Electron Spin...

  8. Antiferromagnetic Spins Do The Twist

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone by E-mail ShareRedAndreasAnodedemonstratesOmcA andon the

  9. Magnetism and superconductivity driven by identical 4f states in a heavy-fermion metal

    SciTech Connect (OSTI)

    Thompson, Joe E [Los Alamos National Laboratory; Nair, S [MAX PLANCK INST.; Stockert, O [MAX PLANCK INST.; Witte, U [INST. FUR FESTKORPERPHYSIK; Nicklas, M [MAX PLANCK INST.; Schedler, R [HELMHOLTZ - ZENTRUM; Bianchi, A [UC, IRVINE; Fisk, Z [UC, IRVINE; Wirth, S [MAX PLANCK INST.; Steglich, K [HELMHOLTZ - ZENTRUM

    2009-01-01T23:59:59.000Z

    The apparently inimical relationship between magnetism and superconductivity has come under increasing scrutiny in a wide range of material classes, where the free energy landscape conspires to bring them in close proximity to each other. Particularly enigmatic is the case when these phases microscopically interpenetrate, though the manner in which this can be accomplished remains to be fully comprehended. Here, we present combined measurements of elastic neutron scattering, magnetotransport, and heat capacity on a prototypical heavy fermion system, in which antiferromagnetism and superconductivity are observed. Monitoring the response of these states to the presence of the other, as well as to external thermal and magnetic perturbations, points to the possibility that they emerge from different parts of the Fermi surface. Therefore, a single 4f state could be both localized and itinerant, thus accounting for the coexistence of magnetism and superconductivity.

  10. Ground state properties and high pressure behavior of plutonium dioxide: Systematic density functional calculations

    E-Print Network [OSTI]

    Zhang, Ping; Zhao, Xian-Geng

    2010-01-01T23:59:59.000Z

    Plutonium dioxide is of high technological importance in nuclear fuel cycle and is particularly crucial in long-term storage of Pu-based radioactive waste. Using first-principles density-functional theory, in this paper we systematically study the structural, electronic, mechanical, thermodynamic properties, and pressure induced structural transition of PuO$_{2}$. To properly describe the strong correlation in the Pu $5f$ electrons, the local density approximation$+U$ and the generalized gradient approximation$+U$ theoretical formalisms have been employed. We optimize the $U$ parameter in calculating the total energy, lattice parameters, and bulk modulus at the nonmagnetic, ferromagnetic, and antiferromagnetic configurations for both ground state fluorite structure and high pressure cotunnite structure. The best agreement with experiments is obtained by tuning the effective Hubbard parameter $U$ at around 4 eV within the LDA$+U$ approach. After carefully testing the validity of the ground state, we further in...

  11. Mean field theory and coherent structures for vortex dynamics on the plane

    E-Print Network [OSTI]

    Chjan C. Lim

    1999-04-20T23:59:59.000Z

    We present a new derivation of the Onsager-Joyce-Montgomery (OJM) equilibrium statistical theory for point vortices on the plane, using the Bogoliubov-Feynman inequality for the free energy, Gibbs entropy function and Landau's approximation. This formulation links the heuristic OJM theory to the modern variational mean field theories. Landau's approximation is the physical counterpart of a large deviation result, which states that the maximum entropy state does not only have maximal probability measure but overwhelmingly large measure relative to other macrostates.

  12. A Minimal Model for Brownian Vortexes Bo Sun, David G. Grier, and Alexander Y. Grosberg

    E-Print Network [OSTI]

    Grier, David

    ]. The second distinguishes them from deterministic machines such as electric motors. The third requires is noise-driven machine that uses thermal fluctuations to extract a steady- state flow of work from, such as elec- tric motors and internal combustion engines, operate de- terministically. Their performance

  13. A Minimal Model for Brownian Vortexes Bo Sun, David G. Grier, and Alexander Y. Grosberg

    E-Print Network [OSTI]

    Grier, David

    ]. The second distinguishes them from deterministic machines such as electric motors. The third requires is noise­driven machine that uses thermal fluctuations to extract a steady­ state flow of work from, such as elec­ tric motors and internal combustion engines, operate de­ terministically. Their performance

  14. Effects of Combustion-Induced Vortex Breakdown on Flashback Limits of Syngas-Fueled Gas Turbine Combustors

    SciTech Connect (OSTI)

    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.

  15. Explosive magnetic reconnection caused by an X-shaped current-vortex layer in a collisionless plasma

    E-Print Network [OSTI]

    Hirota, Makoto; Morrison, Philip J

    2015-01-01T23:59:59.000Z

    A mechanism for explosive magnetic reconnection is investigated by analyzing the nonlinear evolution of a collisionless tearing mode in a two-fluid model that includes the effects of electron inertia and temperature. These effects cooperatively enable a fast reconnection by forming an X-shaped current-vortex layer centered at the reconnection point. A high-resolution simulation of this model for an unprecedentedly small electron skin depth $d_e$ and ion-sound gyroradius $\\rho_s$, satisfying $d_e=\\rho_s$, shows an explosive tendency for nonlinear growth of the tearing mode, where it is newly found that the explosive widening of the X-shaped layer occurs locally around the reconnection point with the length of the X shape being shorter than the domain length and the wavelength of the linear tearing mode. The reason for the onset of this locally enhanced reconnection is explained theoretically by developing a novel nonlinear and nonequilibrium inner solution that models the local X-shaped layer, and then matchin...

  16. Improving Vortex Generators to Enhance the Performance of Air-Cooled Condensers in a Geothermal Power Plant

    SciTech Connect (OSTI)

    Manohar S. Sohal

    2005-09-01T23:59:59.000Z

    This report summarizes work at the Idaho National Laboratory to develop strategies to enhance air-side heat transfer in geothermal air-cooled condensers such that it should not significantly increase pressure drop and parasitic fan pumping power. The work was sponsored by the U.S. Department of Energy, NEDO (New Energy and Industrial Technology Development Organization) of Japan, Yokohama National University, and the Indian Institute of Technology, Kanpur, India. A combined experimental and numerical investigation was performed to investigate heat transfer enhancement techniques that may be applicable to largescale air-cooled condensers such as those used in geothermal power applications. A transient heat transfer visualization and measurement technique was employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements were obtained for a variety of tube and winglet configurations using a single-channel flow apparatus that included four tube rows in a staggered array. Heat transfer and pressure drop measurements were also acquired in a separate multiple-tube row apparatus in the Single Blow Test Facility. In addition, a numerical modeling technique was developed to predict local and average heat transfer for these low-Reynolds number flows, with and without winglets. Representative experimental and numerical results were obtained that reveal quantitative details of local finsurface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. Heat transfer and pressure-drop results were obtained for flow Reynolds numbers based on channel height and mean flow velocity ranging from 700 to 6500. The winglets were of triangular (delta) shape with a 1:2 or 1:3 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface heat transfer results indicate a significant level of heat transfer enhancement (in terms of Colburn j-factor) associated with deployment of the winglets with circular as well as oval tubes. In general, toe-in (common flow up) type winglets appear to have better performance than the toe-out (common flow down) type winglets. Comparisons of heat transfer and pressure drop results for the elliptical tube versus a circular tube with and without winglets are provided. During the course of their independent research, all of the researchers have established that about 10 to 30% enhancement in Colburn j-factor is expected. However, actual increase in heat transfer rate from a heat exchanger employing finned tubes with winglets may be smaller, perhaps on the order of 2 to 5%. It is also concluded that for any specific application, more full-size experimentation is needed to optimize the winglet design for a specific heat exchanger application. If in place of a circular tube, an oval tube can be economically used in a bundle, it is expected that the pressure drop across the tube bundle with the application of vortex generators (winglets) will be similar to that in a conventional circular tube bundle. It is hoped that the results of this research will demonstrate the benefits of applying vortex generators (winglets) on the fins to improve the heat transfer from the air-side of the tube bundle.

  17. United States

    Office of Legacy Management (LM)

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofofOxford SiteToledoSampling at the GrandSr:s I ]Unied States- I

  18. United States

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layeredof2014National Nuclear23,Diversity part 2usingStates

  19. States Government

    Office of Legacy Management (LM)

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou$0.C. 20545 OCT 28SacandagaSite A/Plot3, zm State

  20. Understanding and controlling complex states arising from magnetic frustration

    SciTech Connect (OSTI)

    Zapf, Vivien [Los Alamos National Laboratory

    2012-06-01T23:59:59.000Z

    Much of our national security relies on capabilities made possible by magnetism, in particular the ability to compute and store huge bodies of information as well as to move things and sense the world. Most of these technologies exploit ferromagnetism, i.e. the global parallel alignment of magnetic spins as seen in a bar magnet. Recent advances in computing technologies, such as spintronics and MRAM, take advantage of antiferromagnetism where the magnetic spins alternate from one to the next. In certain crystal structures, however, the spins take on even more complex arrangements. These are often created by frustration, where the interactions between spins cannot be satisfied locally or globally within the material resulting in complex and often non-coplanar spin textures. Frustration also leads to the close proximity of many different magnetic states, which can be selected by small perturbations in parameters like magnetic fields, temperature and pressure. It is this tunability that makes frustrated systems fundamentally interesting and highly desirable for applications. We move beyond frustration in insulators to itinerant systems where the interaction between mobile electrons and the non-coplanar magnetic states lead to quantum magneto-electric amplification. Here a small external field is amplified by many orders of magnitude by non-coplanar frustrated states. This greatly enhances their sensitivity and opens broader fields for applications. Our objective is to pioneer a new direction for condensed matter science at the Laboratory as well as for international community by discovering, understanding and controlling states that emerge from the coupling of itinerant charges to frustrated spin textures.

  1. Magnetization reversal assisted by half antivortex states in nanostructured circular cobalt disks

    SciTech Connect (OSTI)

    Lara, A.; Aliev, F. G., E-mail: farkhad.aliev@uam.es [Dpto. Física de la Materia Condensada, Instituto Nicolas Cabrera (INC) and Condensed Matter Physics Institute (IFIMAC), Universidad Autónoma de Madrid, Madrid (Spain); Dobrovolskiy, O. V. [Physikalisches Institut, Goethe University, Frankfurt am Main (Germany); Physics Department, V. Karazin National University, Kharkiv (Ukraine); Prieto, J. L. [Instituto de Sistemas Optoelectrónicos y Microtecnología (ISOM), Universidad Politecnica de Madrid (Spain); Huth, M. [Physikalisches Institut, Goethe University, Frankfurt am Main (Germany)

    2014-11-03T23:59:59.000Z

    The half antivortex, a fundamental topological structure which determines magnetization reversal of submicron magnetic devices with domain walls, has been suggested also to play a crucial role in spin torque induced vortex core reversal in circular disks. Here, we report on magnetization reversal in circular disks with nanoholes through consecutive metastable states with half antivortices. In-plane anisotropic magnetoresistance and broadband susceptibility measurements accompanied by micromagnetic simulations reveal that cobalt (Co) disks with two and three linearly arranged nanoholes directed at 45° and 135° with respect to the external magnetic field show reproducible step-like changes in the anisotropic magnetoresistance and magnetic permeability due to transitions between different intermediate states mediated by vortices and half antivortices confined to the dot nanoholes and edges, respectively. Our findings are relevant for the development of multi-hole based spintronic and magnetic memory devices.

  2. http://rcc.its.psu.edu/hpc Optimization of a Vortex Finder in a Cyclone Separator using

    E-Print Network [OSTI]

    Bjørnstad, Ottar Nordal

    Tracking with Coupled Multi-Phase Computational Fluid Dynamics Matt Crowell, Mechanical Engineering senior, Penn State Erie, The Behrend College Dr. William Lasher, Professor of Mechanical Engineering, Penn State Erie, The Behrend College Overview Fluidized bed power plants suspend particles in a fluid medium

  3. Annular vortex combustor

    DOE Patents [OSTI]

    Nieh, Sen (Burtonsville, MD); Fu, Tim T. (Camarillo, CA)

    1992-01-01T23:59:59.000Z

    An apparatus for burning coal water fuel, dry ultrafine coal, pulverized l and other liquid and gaseous fuels including a vertically extending outer wall and an inner, vertically extending cylinder located concentrically within the outer wall, the annnular space between the outer wall and the inner cylinder defining a combustion chamber and the all space within the inner cylinder defining an exhaust chamber. Fuel and atomizing air are injected tangentially near the bottom of the combustion chamber and secondary air is introduced at selected points along the length of the combustion chamber. Combustion occurs along the spiral flow path in the combustion chamber and the combined effects of centrifugal, gravitational and aerodynamic forces cause particles of masses or sizes greater than the threshold to be trapped in a stratified manner until completely burned out. Remaining ash particles are then small enough to be entrained by the flue gas and exit the system via the exhaust chamber in the opposite direction.

  4. State-Machine Replication

    E-Print Network [OSTI]

    Venkataramani, Arun

    State-Machine Replication #12;The Problem Clients Server #12;The Problem Clients Server #12;The (state machine) #12;The Solution 1. Make server deterministic (state machine) State machine #12;The Solution 1. Make server deterministic (state machine) 2. Replicate server State machines #12;The Solution 1

  5. Synthesis and characterization of a new layered organic-inorganic hybrid nickel(II) 1,4:5,8-naphthalenediimide bis-phosphonate, exhibiting canted antiferromagnetism, with T{sub c}{approx}21 K

    SciTech Connect (OSTI)

    Bauer, Elvira M. [Istituto di Struttura della Materia del CNR, Sez. di Montelibretti, Via Salaria km 29.3, I-00016 Monterotondo Stazione (Italy)], E-mail: Elvira.Bauer@ism.cnr.it; Bellitto, Carlo [Istituto di Struttura della Materia del CNR, Sez. di Montelibretti, Via Salaria km 29.3, I-00016 Monterotondo Stazione (Italy); Gomez Garcia, Carlos J. [Instituto de Ciencia Molecular, University of Valencia, Pol La Coma s/n, E-46980 Paterna, Valencia (Spain)], E-mail: carlos.gomez@uv.es; Righini, Guido [Istituto di Struttura della Materia del CNR, Sez. di Montelibretti, Via Salaria km 29.3, I-00016 Monterotondo Stazione (Italy)

    2008-05-15T23:59:59.000Z

    A new Ni(II) layered hybrid organic-inorganic compound of formula Ni{sub 2}[(NDI-BP)(H{sub 2}O){sub 2}].2H{sub 2}O has been prepared in very mild conditions from N,N'-bis(2-phosphonoethyl)napthalene-1,4:5,8-tetracarboximide (NDI-BP ligand) and NiCl{sub 2}. The X-ray powder structure characterization of the title compound suggests a pillared layered organic-inorganic hybrid structure. The distance between the organic and inorganic layers has been found to be 17.8 A. The inorganic layers consist of corner sharing [NiO{sub 5}(H{sub 2}O)] octahedra and they are pillared by the diphosphonate groups. DC and AC magnetic measurements as a function of temperature and field indicate the presence of 2D antiferromagnetic exchange interactions between the nearest-neighbor Ni(II) ions below 100 K. A long-range magnetic ordering at T{sub c}{approx}21 K has been established and is attributed to the presence of spin canting. AC magnetic measurements as a function of temperature at different frequencies confirm the occurrence of the magnetic ordering temperature at T=21 K and the presence of a slight structural disorder in the title compound. - Graphical abstract: A new layered hybrid organic-inorganic Ni(II) N,N'-bis(2-phosphonoethyl)-naphthalene 1,4:5,8 tetracarboxydiimide complex has been synthesized and characterized. Magnetic measurements as a function of temperature and at different fields show that the compound is magnetically ordered below T{sub c}{approx}21 K.

  6. State engineering of Bose-Einstein condensate in the optical lattice by a periodic sublattice of dissipative sites

    E-Print Network [OSTI]

    V. S. Shchesnovich

    2012-03-27T23:59:59.000Z

    We introduce the notion of dissipative periodic lattice as an optical lattice with periodically distributed dissipative sites and argue that it allows to engineer unconventional Bose-Einstein superfluids with the complex-valued order parameter. We consider two examples, the one-dimensional dissipative optical lattice, where each third site is dissipative, and the dissipative honeycomb optical lattice, where each dissipative lattice site neighbors three non-dissipated sites. The tight-binding approximation is employed, which allows one to obtain analytical results. In the one-dimensional case the condensate is driven to a coherent Bloch-like state with non-zero quasimomentum, which breaks the translational periodicity of the dissipative lattice. In the two-dimensional case the condensate is driven to a zero quasimomentum Bloch-like state, which is a coherent superposition of four-site discrete vortices of alternating vorticity with the vortex centers located at the dissipative sites.

  7. State of the State's Rural Health

    E-Print Network [OSTI]

    Veiga, Pedro Manuel Barbosa

    of health status, health behavior, or health- care access and Oklahomans do not compare favorablyState of the State's Rural Health 2007 Edition Produced by OSU Center for Rural Health ASnapshotof-4391 January 1, 2007 Dear Reader: Welcome to the Oklahoma State University Center for Rural Health's inaugural

  8. States & Emerging Energy Technologies

    Broader source: Energy.gov (indexed) [DOE]

    States & Emerging Energy Technologies August 15, 2013 DOE's State and Local Technical Assistance Program 2 DOE's Technical Assistance Program * Strategic Energy Planning * Program...

  9. Generalized coherent states

    E-Print Network [OSTI]

    T. G. Philbin

    2013-12-18T23:59:59.000Z

    In the coherent state of the harmonic oscillator, the probability density is that of the ground state subjected to an oscillation along a classical trajectory. Senitzky and others pointed out that there are states of the harmonic oscillator corresponding to an identical oscillatory displacement of the probability density of any energy eigenstate. These generalizations of the coherent state are rarely discussed, yet they furnish an interesting set of quantum states of light that combine features of number states and coherent states. Here we give an elementary account of the quantum optics of generalized coherent states.

  10. LANGEVIN DYNAMICS OF THE TWO STAGE MELTING TRANSITION OF VORTEX MATTER IN Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} IN THE PRESENCE OF STRAIGHT AND OF TILTED COLUMNAR DEFECTS

    SciTech Connect (OSTI)

    GOLDSCHMIDT, YADIN Y.; LIU, Jin-Tao

    2007-08-07T23:59:59.000Z

    In this paper we use London Langevin molecular dynamics simulations to investigate the vortex matter melting transition in the highly anisotropic high-temperature superconductor material Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}#14; in the presence of low concentration of columnar defects (CDs). We reproduce with further details our previous results obtained by using Multilevel Monte Carlo simulations that showed that the melting of the nanocrystalline vortex matter occurs in two stages: a first stage melting into nanoliquid vortex matter and a second stage delocalization transition into a homogeneous liquid. Furthermore, we report on new dynamical measurements in the presence of a current that identifies clearly the irreversibility line and the second stage delocalization transition. In addition to CDs aligned along the c-axis we also simulate the case of tilted CDs which are aligned at an angle with respect to the applied magnetic field. Results for CDs tilted by 45{degree} with respect to c-axis show that the locations of the melting and delocalization transitions are not affected by the tilt when the ratio of flux lines to CDs remains constant. On the other hand we argue that some dynamical properties and in particular the position of the irreversibility line should be affected.

  11. STATE OF CALIFORNIA STATE ENERGY RESOURCES CONSERVATION

    E-Print Network [OSTI]

    .5.4, 25402.8 and 25910. II. HISTORY OF THE PROCEEDING To develop the 2013 Standards, the Energy CommissionSTATE OF CALIFORNIA STATE ENERGY RESOURCES CONSERVATION AND DEVELOPMENT COMMISSION ) 2013 Title 24 Building Energy Efficiency ) Docket No. 12-BSTD-1 Standards Rulemaking Proceeding ) California Code

  12. STATE OF CALIFORNIA STATE ENERGY RESOURCES CONSERVATION

    E-Print Network [OSTI]

    . HISTORY OF THE PROCEEDING To develop the 2013 Standards, the Energy Commission conducted an open, transpaSTATE OF CALIFORNIA STATE ENERGY RESOURCES CONSERVATION AND DEVELOPMENT COMMISSION ) 2013 Title 24 Building Energy Efficiency) Docket No. 12-BSTD-1 Standards Rulemaking Proceeding ) Order No. 12

  13. Colorado State University Colorado State University

    E-Print Network [OSTI]

    Stephens, Graeme L.

    Colorado State University _______________ 1.1 Page 1 Colorado State University In 1870, the Territorial Council and House of Representatives of the Territory of Colorado created the Colorado that same year as Colorado's land-grant college under the Morrill Act of 1862. The Morrill Act provided

  14. Colorado State University Colorado State University

    E-Print Network [OSTI]

    Collett Jr., Jeffrey L.

    Colorado State University Colorado State University In 1870, the Territorial Council and House of Representatives of the Territory of Colorado created the Colorado Agricultural College. When the Territory became. The College admitted its first students in 1879 and received designation that same year as Colorado's land

  15. State Water Quality (Virginia)

    Broader source: Energy.gov [DOE]

    It is the policy of the Commonwealth of Virginia to: (1) protect existing high quality state waters and restore the quality of all other state waters to permit all reasonable public uses and...

  16. Environmental State University

    E-Print Network [OSTI]

    Biology Water Science Nursery Management Plant Breeding Biofuel Feedstocks OUR DEPARTMENT The PLANT specialties, including plant breeding, genetic engineering, sustainable agriculture, ornamental production State University is the only land-grant, Hispanic serving university in the contiguous United States

  17. State Report forState Report forState Report forState Report for From the Research Project

    E-Print Network [OSTI]

    State Report forState Report forState Report forState Report for From the Research Project State Report forState Report forState Report forState Report for Washington University In cooperation with the Washington Department of Fish and Wildlife FINAL REPORT April 2011

  18. States & Emerging Energy Technologies

    Broader source: Energy.gov [DOE]

    This presentation, given through the DOE's Technical Assitance Program (TAP), provides information on States & Emerging Energy Technologies.

  19. AASG STATE GDR

    Energy Science and Technology Software Center (OSTI)

    003198MLTPL00 AASG State Geothermal Data Repository for the National Geothermal Data System.  http://repository.stategeothermaldata.org/repository/ 

  20. State Contracting and Procurement

    E-Print Network [OSTI]

    State Contracting and Procurement Registration System (SCPRS) Illustrated User Manual #12;2 State Contracting and Procurement Registration System (SCPRS) Rev. 4/23/09 Copyright © 2008 RFP Depot, LLC dba Bid@bidsync.com Website: http://www.bidsync.com #12;3 State Contracting and Procurement Registration System (SCPRS) Rev. 4

  1. MICHIGAN STATE UNIVERSITY INTRODUCTIONi.

    E-Print Network [OSTI]

    #12;2 MICHIGAN STATE UNIVERSITY INTRODUCTIONi. Welcome to the Online Professional Master of Science), and the College of Veterinary Medicine (CVM) at Michigan State University (MSU). This booklet contains important, Program Director Online Master of Science in Food Safety Michigan State University 1129 Farm Lane, Rm B 51

  2. Ground State Quantum Computation

    E-Print Network [OSTI]

    Ari Mizel; M. W. Mitchell; Marvin L. Cohen

    1999-08-11T23:59:59.000Z

    We formulate a novel ground state quantum computation approach that requires no unitary evolution of qubits in time: the qubits are fixed in stationary states of the Hamiltonian. This formulation supplies a completely time-independent approach to realizing quantum computers. We give a concrete suggestion for a ground state quantum computer involving linked quantum dots.

  3. Sustainability Cal State Fullerton

    E-Print Network [OSTI]

    de Lijser, Peter

    Sustainability at Cal State Fullerton A Report from the Sustainability Initiative Study Group October 28, 2008 #12;Sustainability at Cal State Fullerton A Report from the Sustainability Initiative Safety Sally Yassine Contracts & Procurement #12;Sustainability at Cal State Fullerton A Report from

  4. Black brane steady states

    E-Print Network [OSTI]

    Amado, Irene

    2015-01-01T23:59:59.000Z

    We follow the evolution of an asymptotically AdS black brane with a fixed temperature gradient at spatial infinity until a steady state is formed. The resulting energy density and energy flux of the steady state in the boundary theory are compared to a conjecture on the behavior of steady states in conformal field theories. Very good agreement is found.

  5. State Clean Energy Policies Analysis: State, Utility, and Municipal...

    Open Energy Info (EERE)

    State, Utility, and Municipal Loan Programs Jump to: navigation, search Name State Clean Energy Policies Analysis: State, Utility, and Municipal Loan Programs AgencyCompany...

  6. State Technologies Advancement Collaborative

    SciTech Connect (OSTI)

    David S. Terry

    2012-01-30T23:59:59.000Z

    The U. S. Department of Energy (DOE), National Association of State Energy Officials (NASEO), and Association of State Energy Research and Technology Transfer Institutions (ASERTTI) signed an intergovernmental agreement on November 14, 2002, that allowed states and territories and the Federal Government to better collaborate on energy research, development, demonstration and deployment (RDD&D) projects. The agreement established the State Technologies Advancement Collaborative (STAC) which allowed the states and DOE to move RDD&D forward using an innovative competitive project selection and funding process. A cooperative agreement between DOE and NASEO served as the contracting instrument for this innovative federal-state partnership obligating funds from DOE's Office of Energy Efficiency and Renewable Energy and Office of Fossil Energy to plan, fund, and implement RDD&D projects that were consistent with the common priorities of the states and DOE. DOE's Golden Field Office provided Federal oversight and guidance for the STAC cooperative agreement. The STAC program was built on the foundation of prior Federal-State efforts to collaborate on and engage in joint planning for RDD&D. Although STAC builds on existing, successful programs, it is important to note that it was not intended to replace other successful joint DOE/State initiatives such as the State Energy Program or EERE Special Projects. Overall the STAC process was used to fund, through three competitive solicitations, 35 successful multi-state research, development, deployment, and demonstration projects with an overall average non-federal cost share of 43%. Twenty-two states were awarded at least one prime contract, and organizations in all 50 states and some territories were involved as subcontractors in at least one STAC project. Projects were funded in seven program areas: (1) Building Technologies, (2) Industrial Technologies, (3) Transportation Technologies, (4) Distributed Energy Resources, (5) Hydrogen Technology Learning Centers, (6) Fossil Energy, and (7) Rebuild America.

  7. Experimental and semiempirical method to determine the Pauli-limiting field in quasi-two-dimensional superconductors as applied to ?-(BEDT-TTF)2Cu(NCS)2: strong evidence of a FFLO state

    SciTech Connect (OSTI)

    Agosta, C. C.; Jin, J.; Coniglio, W. A.; Smith, B. E.; Cho, K.; Mihut, I.; Martin, C.; Tozer, S. W.; Murphy, T. P.; Palm, E. C.; Schlueter, J. A.; Kurmoo, M. (Materials Science Division); (Clark Univ.); (Nat. High Field Magnet Lab.); (The Royal Inst.)

    2012-01-01T23:59:59.000Z

    We present upper critical field data for {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2} with the magnetic field close to parallel and parallel to the conducting layers. We show that we can eliminate the effect of vortex dynamics in these layered materials if the layers are oriented within 0.3-inch of parallel to the applied magnetic field. Eliminating vortex effects leaves one remaining feature in the data that corresponds to the Pauli paramagnetic limit (H{sub p}). We propose a semiempirical method to calculate the H{sub p} in quasi-2D superconductors. This method takes into account the energy gap of each of the quasi-2D superconductors, which is calculated from specific-heat data, and the influence of many-body effects. The calculated Pauli paramagnetic limits are then compared to critical field data for the title compound and other organic conductors. Many of the examined quasi-2D superconductors, including the above organic superconductors and CeCoIn{sub 5}, exhibit upper critical fields that exceed their calculated H{sub p} suggesting unconventional superconductivity. We show that the high-field low-temperature state in {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2} is consistent with the Fulde-Ferrell-Larkin-Ovchinnikov state.

  8. Amplitude mediated chimera states

    E-Print Network [OSTI]

    Gautam C Sethia; Abhijit Sen; George L. Johnston

    2013-10-04T23:59:59.000Z

    We investigate the possibility of obtaining chimera state solutions of the non-local Complex Ginzburg-Landau Equation (NLCGLE) in the strong coupling limit when it is important to retain amplitude variations. Our numerical studies reveal the existence of a variety of amplitude mediated chimera states (including stationary and non-stationary two cluster chimera states), that display intermittent emergence and decay of amplitude dips in their phase incoherent regions. The existence regions of the single-cluster chimera state and both types of two cluster chimera states are mapped numerically in the parameter space of $C_1$ and $C_2$ the linear and nonlinear dispersion coefficients respectively of the NLCGLE. They represent a new domain of dynamical behaviour in the well explored rich phase diagram of this system. The amplitude mediated chimera states may find useful applications in understanding spatio-temporal patterns found in fluid flow experiments and other strongly coupled systems.

  9. Michigan State University Alumni Association MICHIGAN STATE UNIVERSITY

    E-Print Network [OSTI]

    Michigan State University Alumni Association Bylaws #12;2 MICHIGAN STATE UNIVERSITY ALUMNI of the organization shall be the Michigan State University Alumni Association (hereinafter, the "Association"). Section 2 Mission Statement The Michigan State University Alumni Association supports and enhances

  10. State Agency Loan Program

    Broader source: Energy.gov [DOE]

    The State Agency Loan Program (SALP) was established in 1991 using funds from the Energy Overcharge Restitution Fund. Through this revolving loan program, the Maryland Energy Administration (MEA)...

  11. Solid-State Lighting

    Broader source: Energy.gov (indexed) [DOE]

    research and design. Quality LED luminaires require program designed to successfully move solid-state lighting precise design of several components -LED arrays, electronic into the...

  12. State and Local Incentives

    Broader source: Energy.gov [DOE]

    To help you make energy efficiency improvements in your commercial building, your state and/or local community might offer incentives or have special programs.

  13. State Gasoline Taxes

    E-Print Network [OSTI]

    Learned, Edmund Philip

    1925-03-15T23:59:59.000Z

    BULLETIN OF THE UNIVERSITY OF KANSAS HUMANISTIC STUDIES Vol. III March 15, 192S No. 4 State Gasoline Taxes BY KDMUNI) IV LKAENKI), A. B., A, M. Instructor in Economics and Commerce The Unlvmity of Kansas PUBLISHED BY THE UNIVERSITY l... vast sums of money, Oregon was the first state to adopt a tax on gasoline to provide revenue for building and maintaining roads. Since this adoption in 1919, many states have passed laws provid ing for gasoline taxes until now forty-four states...

  14. State Energy Strategic Planning

    Broader source: Energy.gov [DOE]

    U.S. Department of Energy (DOE) Technical Assistance Program (TAP) presentation at a TAP webinar held on April 3, 2013 and dealing with state energy strategic planning.

  15. Solid State Division

    SciTech Connect (OSTI)

    Green, P.H.; Watson, D.M. (eds.)

    1989-08-01T23:59:59.000Z

    This report contains brief discussions on work done in the Solid State Division of Oak Ridge National Laboratory. The topics covered are: Theoretical Solid State Physics; Neutron scattering; Physical properties of materials; The synthesis and characterization of materials; Ion beam and laser processing; and Structure of solids and surfaces. (LSP)

  16. United States Department of

    E-Print Network [OSTI]

    Hills National Forest uses such a habitat capability model (HABCAP), but its accuracy is largely unknown, Wildlife Biologist with Black Hills National Forest, Custer, SD 2 South Dakota State UniversityUnited States Department of Agriculture Forest Service Rocky Mountain Forest and Range Experiment

  17. Compatibility of quantum states

    SciTech Connect (OSTI)

    Poulin, David; Blume-Kohout, Robin [Theoretical Division, Los Alamos National Laboratory, MS-B210, Los Alamos, New Mexico 87545 (United States)

    2003-01-01T23:59:59.000Z

    We introduce a measure of compatibility between quantum states--the likelihood that two density matrices describe the same object. Our measure is motivated by two elementary requirements, which lead to a natural definition. We list some properties of this measure, and discuss its relation to the problem of combining two observers' states of knowledge.

  18. United States of Agriculture

    E-Print Network [OSTI]

    in wildlife management from the University of New Hampshire in 1988. She joined the Intermountain Research Station in 1993 after working for the States of New Hampshire and Wyoming on projects involving wetlandUnited States Department of Agriculture Forest Service Intermountain Research Station General

  19. New State Standards

    E-Print Network [OSTI]

    Lopez, F. A.

    2011-01-01T23:59:59.000Z

    residential 2009 IECC, commercial 2009 IECC, air sealing and blower doors; ? A resource library of compliance tools, software, and PNNL checklists. 15 CATEE-Dallas 11-09-2011 Questions? Felix Lopez, P.E. State Energy Conservation Office 512...

  20. Greening of State Government

    Broader source: Energy.gov [DOE]

    In July 2005, Colorado’s governor signed Executive Order D005 05, mandating that state agencies and departments evaluate business operations and implement new programs “to promote environmentally...

  1. United States Environmental Protection

    E-Print Network [OSTI]

    environmental problems today and building a science knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect our health, and prevent or reduce environmental risksUnited States Environmental Protection Agency Hydrogeologic Framework, Ground-Water Geochemistry

  2. Solid state switch

    DOE Patents [OSTI]

    Merritt, Bernard T. (Livermore, CA); Dreifuerst, Gary R. (Livermore, CA)

    1994-01-01T23:59:59.000Z

    A solid state switch, with reverse conducting thyristors, is designed to operate at 20 kV hold-off voltage, 1500 A peak, 1.0 .mu.s pulsewidth, and 4500 pps, to replace thyratrons. The solid state switch is more reliable, more economical, and more easily repaired. The switch includes a stack of circuit card assemblies, a magnetic assist and a trigger chassis. Each circuit card assembly contains a reverse conducting thyristor, a resistor capacitor network, and triggering circuitry.

  3. Roanoke River Basin Bi-State Commission (Multiple States)

    Broader source: Energy.gov [DOE]

    The Roanoke River Basin Bi-State Commission was established as a bi-state commission composed of members from the Commonwealth of Virginia and the State of North Carolina. The purpose of the...

  4. State of the States 2010: Fuel Cells in America | Department...

    Broader source: Energy.gov (indexed) [DOE]

    States 2010: Fuel Cells in America State of the States 2010: Fuel Cells in America This report, written by Fuel Cells 2000 and partially funded by the U.S. Department of Energy's...

  5. GREEN'S FUNCTIONS OF VORTEX OPERATORS

    E-Print Network [OSTI]

    Polchinski, Joseph

    2013-01-01T23:59:59.000Z

    surface clustering the Green's function 5.1 actually spreadsb. Another graph for the same Green's function. c. Anothercomposite divergences. The Green's function 5.6, considered

  6. dynamo_double_vortex.pdf

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched5 Industrial Carbon Capture and Storageconvert 2 3 DEPARTMENTThermal Offset

  7. NREL: State and Local Governments - The Effect of State Policy...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fact Sheet Blog post Podcast Press release Slide 1: Intro slide Implementing State and Local Markets Specific groupings of state policies stimulate distributed PV markets over...

  8. State Opportunities for Action: Update of States' CHP Activities...

    Broader source: Energy.gov (indexed) [DOE]

    & Publications CHP: Connecting the Gap between Markets and Utility Interconnection and Tariff Practices, 2006 Challenges Facing CHP: A State-by-State Assessment (ACEEE), 2011 2008...

  9. Western Interstate Nuclear Compact State Nuclear Policy (Multiple States)

    Broader source: Energy.gov [DOE]

    Legislation authorizes states' entrance into the Western Interstate Nuclear Compact, which aims to undertake the cooperation of participating states in deriving the optimum benefit from nuclear and...

  10. State Energy Program Helps States Plan and Implement Efficiency...

    Office of Environmental Management (EM)

    More Documents & Publications State Energy Program Helps States Plan and Implement Energy Efficiency Rebuilding Greensburg, Kansas, as a Model Green Community: A Case Study;...

  11. State Clean Energy Policies Analysis (SCEPA): State Policy and...

    Open Energy Info (EERE)

    Manufacturing Jump to: navigation, search Tool Summary LAUNCH TOOL Name: State Clean Energy Policies Analysis (SCEPA): State Policy and the Pursuit of Renewable Energy...

  12. State Energy Efficiency Design Program

    Broader source: Energy.gov [DOE]

    Oregon's State Energy Efficiency Design Program (SEED) was originally established in 1991. This program, codified in state law, directs state agencies to work with the Oregon Department of Energy...

  13. MICHIGAN STATE UNIVERSITY PHILANTHROPIST AWARD

    E-Print Network [OSTI]

    MICHIGAN STATE UNIVERSITY PHILANTHROPIST AWARD The MSU Alumni Association annually seeks and accepts nominations for the Michigan State University PHILANTHROPIST AWARD. This award is presented-going financial support and leadership to Michigan State University. The candidates will have demonstrated

  14. Solid state switch

    DOE Patents [OSTI]

    Merritt, B.T.; Dreifuerst, G.R.

    1994-07-19T23:59:59.000Z

    A solid state switch, with reverse conducting thyristors, is designed to operate at 20 kV hold-off voltage, 1,500 A peak, 1.0 [mu]s pulsewidth, and 4,500 pps, to replace thyratrons. The solid state switch is more reliable, more economical, and more easily repaired. The switch includes a stack of circuit card assemblies, a magnetic assist and a trigger chassis. Each circuit card assembly contains a reverse conducting thyristor, a resistor capacitor network, and triggering circuitry. 6 figs.

  15. Quantum chimera states

    E-Print Network [OSTI]

    David Viennot; Lucile Aubourg

    2014-11-19T23:59:59.000Z

    We study a theoretical model of closed quasi-hermitian chain of spins which exhibits quantum analogues of chimera states, i.e. long life classical states for which a part of an oscillator chain presents an ordered dynamics whereas another part presents a disordered chaotic dynamics. For the quantum analogue, the chimera behavior deals with the entanglement between the spins of the chain. We discuss the entanglement properties, quantum chaos, quantum disorder and semi-classical similarity of our quantum chimera system. The quantum chimera concept is novel and induces new perspectives concerning the entanglement of multipartite systems.

  16. FY 2009 State Table

    Broader source: Energy.gov (indexed) [DOE]

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of EnergyEnergyENERGYWomentheATLANTA, GA5 &of EnergyOrganization (dollarsControlState6State Tables

  17. Biodiversity conservation and state sovereignty.

    E-Print Network [OSTI]

    Echeverria, Hugo.

    2005-01-01T23:59:59.000Z

    ??This thesis examines the influence of contemporary approaches to biodiversity conservation on conceptions of state sovereignty over natural resources. Traditional approaches to state sovereignty have… (more)

  18. Josephson Coupled Moore-Read States

    E-Print Network [OSTI]

    Moller, Gunnar; Hormozi, Layla; Slingerland, Joost; Simon, Steven H.

    2014-12-01T23:59:59.000Z

    - ples, and we may hope that the physical systems will be described by the same phase of matter as the model, and will therefore have the same universal properties. Fur- ther, with modern quantum technologies, such as cold atoms, trapped ions... of the composite fermion super- conductor. In addition, one needs to consider the pos- sible fusion channels of the Majorana zero modes in the vortex cores.35 The introduction of Josephson tunnel- ing between the layers can then be understood as lock- ing...

  19. STATE OF THE CLIMATE Jessica Blunden Derek S. Arndt

    E-Print Network [OSTI]

    melting and a negative mass balance. To the west, the mass loss from glaciers and ice caps in the Canadian and ice caps (outside Greenland); Greenland Ice Sheet; Permafrost; Lake ice; Sea ice; Ocean; and Ocean in the dominant wind pat- tern, responding to changes in the polar vortex, which affected the distribution

  20. State of Spacef p State of Space 2009

    E-Print Network [OSTI]

    Van Volkenburgh, Elizabeth

    State of Spacef p 2009 State of Space 2009 DRAFT ­ For Discussion Only #12;UW Space throughout the World Owned or Leased State of Space 2009 DRAFT ­ For Discussion Only *Space recorded with the Office of Planning & Budgeting or the Real Estate Office #12;UW Space throughout the United States Owned or Leased

  1. Variational transition state theory

    SciTech Connect (OSTI)

    Truhlar, D.G. [Univ. of Minnesota, Minneapolis (United States)

    1993-12-01T23:59:59.000Z

    This research program involves the development of variational transition state theory (VTST) and semiclassical tunneling methods for the calculation of gas-phase reaction rates and selected applications. The applications are selected for their fundamental interest and/or their relevance to combustion.

  2. United States Department of

    E-Print Network [OSTI]

    play an important role in a national program for reducing greenhouse gas emissions. The conversion potential through conversion of nonforest land to forest land and through the management of forest lands and sinks in the United States can be identified. International treaties on greenhouse gas reduction require

  3. dddddddddddddddddddddddddddddddddddddd United States

    E-Print Network [OSTI]

    Hubbard, Susan

    , and is on the verge of a major water shortage. As vineyards consume more rural acre- age, competition for water irrigation. However, California uses the largest volume of water of any state in the nation resources is increasing, which has increased the pres- sure on California vintners to use water more

  4. Washington State Electric Vehicle

    E-Print Network [OSTI]

    California at Davis, University of

    Washington State Electric Vehicle Implementation Bryan Bazard Maintenance and Alternate Fuel Technology Manager #12;Executive Order 14-04 Requires the procurement of electric vehicles where and equipment with electricity or biofuel to the "extent practicable" by June 2015 1. The vehicle is due

  5. United States Environmental Protection

    E-Print Network [OSTI]

    federal and state agencies to prepare for emergencies at U.S. nuclear plants, transportation accidents is actively involved with other U.S. government agencies for preparing to respond to acts of chemical, EPAprovides support to the Emergency ManagementAgency by: (1) establishing guidelines for protecting

  6. United States Environmental

    E-Print Network [OSTI]

    Loudon, Catherine

    Protect Your Family From Lead in Your Home United States Environmental Protection Agency United · What you can do to protect your family · Where to go for more information Before renting or buying Family from Lead Hazards If you think your home has lead-based paint: · Don't try to remove lead

  7. United States Department of

    E-Print Network [OSTI]

    United States Department of Agriculture Managing Habitats for White-tailed DeerForest Service Rocky Mountain Forest and Range Experiment Station Fort Collins, Colorado 80526 General Technical Report RM-GTR-274 Black Hills and Bear Lodge Mountains of South Dakota and Wyoming Carolyn Hull Sieg and Kieth E

  8. United States Department of

    E-Print Network [OSTI]

    : For additional copies: U.S. FOREST SERVICE U.S. Forest Service 11 CAMPUS BLVD SUITE 200 Publications Distribution Forest, New Hampshire, began in 1932. One of the studies, still maintained today, consisted of severalUnited States Department of Agriculture Forest Service Northern Research Station Research Paper NRS

  9. United States Department of

    E-Print Network [OSTI]

    Station at Durham, New Hampshire. The computer program described in this publication was created usingUnited States Department of Agriculture Forest Service Northern Research Station General Technical://www.nrs.fs.fed.us/ Published by: For additional copies: U.S. FOREST SERVICE U.S. Forest Service 11 CAMPUS BLVD SUITE 200

  10. United States Department of

    E-Print Network [OSTI]

    copies: USDA FOREST SERVICE USDA Forest Service 11 CAMPUS BLVD SUITE 200 Publications Distribution at Durham, New Hampshire; JENNIFER C. JENKINS, jjenkins@fs.fed.us, is a research foresterUnited States Department of Agriculture Forest Service Northeastern Research Station General

  11. United States Department of

    E-Print Network [OSTI]

    are thought to contribute to carbon sequestration, including current debates on this topic. The science regarding forestry and carbon sequestration is more advanced and less controversial than that for range, land management, carbon sequestration, carbon markets, United States. #12;ii Executive Summary

  12. FISHERY STATISTICS UNITED STATES

    E-Print Network [OSTI]

    FISHERY STATISTICS OF THE UNITED STATES 1973 STATISTICAL DIGEST NO. 67 Prepared by STATISTICS a review of the fishery statistics for the year 1973 . These statistics include data on the volume and value of landings of fishery products, employment 1n the fish- eries, quantity of gear operated, number

  13. FISHERY STATISTICS UNITED STATES

    E-Print Network [OSTI]

    FISHERY STATISTICS OF THE UNITED STATES 1971 STATISTICAL DIGEST NO. 65 Prepared by STATISTICS ry statistics for the year 1971 . These statistics include data on the volume and value of landings of fishery products, employment in the fishe ries, quantity of gear operated, number of fishing craft e

  14. United States Department of

    E-Print Network [OSTI]

    Brown, Gregory G.

    Assessment Thomas M. Quigley, Editor U.S. Department of Agriculture Forest Service Pacific Northwest Research, and Andy Wilson. Thomas M. Quigley Editor United States Department of Agriculture Forest Service United Service, Pacific Northwest Research Station. 120 p. (Quigley, Thomas M., ed.; Interior Columbia Basin

  15. Transboundary aquifers: Southwestern states assess

    E-Print Network [OSTI]

    Wythe, Kathy

    2008-01-01T23:59:59.000Z

    tx H2O | pg. 14 Southwestern states assess Researchers from three universities in Texas, New Mexico, and Arizona and from the U.S. Geological Survey (USGS) are partnering on a new project to evaluate aquifers that span the United States... and Mexico borders. The federally funded project, known as United States-Mexico Transboundary Aquifer Assessment, will provide a scientific foundation for state and local officials to address pressing water resources challenges in the United States...

  16. State Energy Program Operations Manual

    SciTech Connect (OSTI)

    Office of Building Technology, State and Community Programs

    1999-03-17T23:59:59.000Z

    The State Energy Program Operations Manual is a reference tool for the states and the program officials at the U.S. Department of Energy's Office of Building Technology, State and Community Programs and Regional Support Offices as well as State Energy Offices. The Manual contains information needed to apply for and administer the State Energy Program, including program history, application rules and requirements, and program administration and monitoring requirements.

  17. Representation of State Property Systems

    E-Print Network [OSTI]

    Diederik Aerts; Sylvia Pulmannova

    2008-11-15T23:59:59.000Z

    A 'state property system' is the mathematical structure which models an arbitrary physical system by means of its set of states, its set of properties, and a relation of 'actuality of a certain property for a certain state'. We work out a new axiomatization for standard quantum mechanics, starting with the basic notion of state property system, and making use of a generalization of the standard quantum mechanical notion of 'superposition' for state property systems.

  18. Bound States in Graphene

    E-Print Network [OSTI]

    Kumar S. Gupta; Siddhartha Sen

    2008-06-03T23:59:59.000Z

    We present a quantum analysis of the massless excitations in graphene with a charge impurity. When the effective charge exceeds a certain critical value, the spectrum is quantized and is unbounded from below. The corresponding eigenstates are square-integrable at infinity and have a rapidly oscillatory behaviour in the short distance, which can be interpreted as a fall to the centre. Using a cutoff regularization, we show that the effective Coulomb interaction strength is driven to its critical value under the renormalization group flow. In the subcritical region, we find bound states with imaginary values of the energy for certain range of the system parameters. The physical significance of these bound states with imaginary eigenvalues is discussed.

  19. Nozick's minimal state?

    E-Print Network [OSTI]

    Russell, Darrell James

    1995-01-01T23:59:59.000Z

    seemed to have problems doing so, myself. Finally, I must give special acknowledgment to Debbie Hutchins for listening to me whine. TABLE OF CONTENTS ABSTRACT. DEDICATION. Page iv ACKNOWLEDGMENTS. . TABLE OF CO~5. . CHAPTER I INTRODUCTION. II.... Protective Policy Possibilities. . IV PROTECTIVE WELFARE. 8 11 14 25 29 30 34 39 43 50 56 Case 1: Roads. . Case 2: Education. Case 3: The Marshall Plan. . Arguments and Analysis. V A NOZICKIAN STATE Policy Objedions...

  20. Incidence of Federal and State Gasoline Taxes

    E-Print Network [OSTI]

    Chouinard, Hayley; Perloff, Jeffrey M.

    2003-01-01T23:59:59.000Z

    State Specific * Share of Gasoline State Specific * (Share of Gasoline) 2 StateSpecific * (Share of Gasoline) 3 State Specific * (Share of

  1. State of the States: Fuel Cells in America 2013

    Fuel Cell Technologies Publication and Product Library (EERE)

    This October 2013 report, written by Fuel Cells 2000 and partially funded by the U.S. Department of Energy's Fuel Cell Technologies Office, continues to build on the April 2010 State of the States rep

  2. State of the States: Fuel Cells in America 2012

    Fuel Cell Technologies Publication and Product Library (EERE)

    This report, written by Fuel Cells 2000 and partially funded by the U.S. Department of Energy's Fuel Cell Technologies Program, continues to build on the April 2010 State of the States report that pro

  3. State Energy Alternatives: Alternative Energy Resources by State

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    This U.S. map provides state by state information on incentives and laws related to alternative fuels and advanced vehicles. Discover what's available in each state for innovation grants, infrastructure grants, and production grants and who to contact. Find out how many alternative refueling stations are available in each state and where they are. Tennessee, for example, in 2009, has 114 alternative refueling stations: 36 biodiesel, 1 electrical, 29 ethanol, 4 natural gas, and 44 propane. There are also 5 Truck Stop Electrification (TSE) sites in Tennessee. Users can also find out from this map interface the contacts for Clean Cities in a state, information about renewable energy projects and activities in each state, fuel prices across a state, and biomass potential resources and current production in each state.

  4. Solid state optical microscope

    DOE Patents [OSTI]

    Young, I.T.

    1983-08-09T23:59:59.000Z

    A solid state optical microscope wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. A galvanometer scanning mirror, for scanning in one of two orthogonal directions is provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal. 2 figs.

  5. Solid state optical microscope

    DOE Patents [OSTI]

    Young, Ian T. (Pleasanton, CA)

    1983-01-01T23:59:59.000Z

    A solid state optical microscope wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. A galvanometer scanning mirror, for scanning in one of two orthogonal directions is provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal.

  6. Unied States Government

    Office of Legacy Management (LM)

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofofOxford SiteToledoSampling at the GrandSr:s I ]Unied States

  7. United States Goveinment *

    Office of Legacy Management (LM)

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofofOxford SiteToledoSampling at the GrandSr:s I ]Unied States- Iwx l

  8. United States Government

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layeredof2014National Nuclear23,Diversity part 2using States

  9. State Nuclear Profiles 2010

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) " ,"ClickPipelines AboutDecemberSteamYear Jan FebThousand Cubicin North Dakota (MillionState Heating Oil

  10. STATE OF WASHINGTON August

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -the Mid-Infrared0 ResourceAwards SAGEComplainant, V. UNITED STATES

  11. Solid state oxygen sensor

    DOE Patents [OSTI]

    Garzon, Fernando H. (Sante Fe, NM); Chung, Brandon W. (Los Alamos, NM); Raistrick, Ian D. (Los Alamos, NM); Brosha, Eric L. (Los Alamos, NM)

    1996-01-01T23:59:59.000Z

    Solid state oxygen sensors are provided with a yttria-doped zirconia as an electrolyte and use the electrochemical oxygen pumping of the zirconia electrolyte. A linear relationship between oxygen concentration and the voltage arising at a current plateau occurs when oxygen accessing the electrolyte is limited by a diffusion barrier. A diffusion barrier is formed herein with a mixed electronic and oxygen ion-conducting membrane of lanthanum-containing perovskite or zirconia-containing fluorite. A heater may be used to maintain an adequate oxygen diffusion coefficient in the mixed conducting layer.

  12. FY 2006 State Table

    Broader source: Energy.gov (indexed) [DOE]

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of EnergyEnergyENERGYWomentheATLANTA, GA5 &of EnergyOrganization (dollars in thousands - OMB6State

  13. FY 2008 State Table

    Broader source: Energy.gov (indexed) [DOE]

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of EnergyEnergyENERGYWomentheATLANTA, GA5 &of EnergyOrganization (dollarsControlState Table

  14. FY 2011 State Table

    Broader source: Energy.gov (indexed) [DOE]

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of EnergyEnergyENERGYWomentheATLANTA, GA5 &of EnergyOrganizationtotal FY 2010 LDRD51The total1State

  15. UNITED STATES OF AMERICA

    Broader source: Energy.gov (indexed) [DOE]

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment of EnergyProgram2-26 Date:CharterDepartmentDOE LM issued theUNITED STATES UNITED

  16. UNITED STATES OF AMERICA

    Broader source: Energy.gov (indexed) [DOE]

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment of EnergyProgram2-26 Date:CharterDepartmentDOE LM issued theUNITED STATES

  17. UNITED STATES OF AMERICA

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustion |Energy Usage »of EnergyTheTwo New Energyof Energy8, UNITED STATES DEPARTMENT

  18. State DOT: Colorado State Report Questions on MEPDG Implementation

    E-Print Network [OSTI]

    State DOT: Colorado State Report Questions on MEPDG Implementation 1. Summarize your state's status as far as MEPDG Implementation. Currently, CDOT is in the process of validating the MEPDG in Colorado and calibrating it to Colorado performance data. 2. What efforts have been made toward local calibration? CDOT has

  19. Nevada State Energy Reduction Plan

    Broader source: Energy.gov [DOE]

    As mandated by the Nevada statutes, the Nevada Energy Office prepared a state energy reduction plan which requires state agencies, departments, and other entities in the Executive Branch to reduce...

  20. Energy Standards for State Agencies

    Broader source: Energy.gov [DOE]

    In May 2006 the governor of Alabama issued Executive Order 33 mandating that state departments and agencies encourage and promote the conservation of energy in state-owned buildings.In November...

  1. State Barriers to CHP Development

    E-Print Network [OSTI]

    Chittum, A.; Kaufman, N.

    2011-01-01T23:59:59.000Z

    Every year, ACEEE collects data on regulatory policies in each state that theoretically serve to promote and discourage combined heat and power (CHP) development. In our annual State Energy Efficiency Scorecard (5), we assess the regulatory...

  2. State Energy Program in Kentucky

    SciTech Connect (OSTI)

    Not Available

    2003-04-01T23:59:59.000Z

    The State Energy Program in Kentucky summarizes the important renewable energy and energy efficiency projects and recent successes of the Kentucky Division of Energy, which is the state energy office in the Kentucky.

  3. DESIGN VERIFICATION WITH STATE INVARIANTS

    E-Print Network [OSTI]

    Sekerinski, Emil

    . Transitions between states can assign to and depend on global variables of arbitrary types, thus lifting.1 Statechart with invariants for a TV set. Statecharts on their own do not immediately lead to opportunities to behavioural state machines and protocol state machines [18]. Consider the TV control example in Figure 1

  4. Penn State DOE GATE Program

    SciTech Connect (OSTI)

    Anstrom, Joel

    2012-08-31T23:59:59.000Z

    The Graduate Automotive Technology Education (GATE) Program at The Pennsylvania State University (Penn State) was established in October 1998 pursuant to an award from the U.S. Department of Energy (U.S. DOE). The focus area of the Penn State GATE Program is advanced energy storage systems for electric and hybrid vehicles.

  5. FISHERY STATISTICS E UNITED STATES

    E-Print Network [OSTI]

    SH 11 .A443X FISH FISHERY STATISTICS E UNITED STATES ^ 1951 &ch 3. \\§^ ^/'· m:^ STATISTICAL DIGEST. Farley, Director Statistical Digest 30 FISHERY STATISTICS OF THE UNITED STATES 1951 BY A. W. ANDERSON;Fishery Statistics of the United States and Alaska are compiled and published annually to make available

  6. Distinguishability of the Bell states

    E-Print Network [OSTI]

    Sibasish Ghosh; Guruprasad Kar; Anirban Roy; Aditi Sen De; Ujjwal Sen

    2001-07-03T23:59:59.000Z

    More than two multipartite orthogonal states cannot always be discriminated (with certainty) if only local operations and classical communication (LOCC) are allowed. Using an existing inequality among the measures of entanglement, we show that any three Bell states cannot be discriminated by LOCC. Exploiting the inequality, we calculate the distillable entanglement of a certain class of (4\\otimes 4) mixed states.

  7. Boise State University Graduate Catalog

    E-Print Network [OSTI]

    Barrash, Warren

    for the State of Idaho and for you, the students, who enroll in its programs. Graduate education at Boise State. Boise State is located within the largest metropolitan area of Idaho and attracts more than one million, and for other education or allied agencies. Catalogs, bulletins, course and fee schedules, etc

  8. Maximal rank of extremal marginal tracial states

    E-Print Network [OSTI]

    Hiromichi Ohno

    2009-11-18T23:59:59.000Z

    States on coupled quantum system whose restrictions to each subsystems are normalized traces are called marginal tracial states. We investigate extremal marginal tracial states and maximal rank of such states. Diagonal marginal tracial states are also considered.

  9. Solid state rapid thermocycling

    DOE Patents [OSTI]

    Beer, Neil Reginald; Spadaccini, Christopher

    2014-05-13T23:59:59.000Z

    The rapid thermal cycling of a material is targeted. A solid state heat exchanger with a first well and second well is coupled to a power module. A thermoelectric element is coupled to the first well, the second well, and the power module, is configured to transfer thermal energy from the first well to the second well when current from the power module flows through the thermoelectric element in a first direction, and is configured to transfer thermal energy from the second well to the first well when current from the power module flows through the thermoelectric element in a second direction. A controller may be coupled to the thermoelectric elements, and may switch the direction of current flowing through the thermoelectric element in response to a determination by sensors coupled to the wells that the amount of thermal energy in the wells falls below or exceeds a pre-determined threshold.

  10. Optimal broadcasting of mixed states

    SciTech Connect (OSTI)

    Dang Guifang; Fan Heng [Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)

    2007-08-15T23:59:59.000Z

    The N to M (M{>=}N) universal quantum broadcasting of mixed states {rho}{sup xN} is proposed for a qubit system. The broadcasting of mixed states is universal and optimal in the sense that the shrinking factor is independent of the input state and achieves the upper bound. The quantum broadcasting of mixed qubits is a generalization of the universal quantum cloning machine for identical pure input states. A pure state decomposition of the identical mixed qubits {rho}{sup xN} is obtained.

  11. Packaging of solid state devices

    DOE Patents [OSTI]

    Glidden, Steven C.; Sanders, Howard D.

    2006-01-03T23:59:59.000Z

    A package for one or more solid state devices in a single module that allows for operation at high voltage, high current, or both high voltage and high current. Low thermal resistance between the solid state devices and an exterior of the package and matched coefficient of thermal expansion between the solid state devices and the materials used in packaging enables high power operation. The solid state devices are soldered between two layers of ceramic with metal traces that interconnect the devices and external contacts. This approach provides a simple method for assembling and encapsulating high power solid state devices.

  12. Fake state attack on practically decoy state quantum key distribution

    E-Print Network [OSTI]

    Yong-gang Tan

    2012-02-15T23:59:59.000Z

    In this paper, security of practically decoy state quantum key distribution under fake state attack is considered. If quantum key distribution is insecure under this type of attack, decoy sources can not also provide it with enough security. Strictly analysis shows that Eve should eavesdrop with the aid of photon-number-resolving instruments. In practical implementation of decoy state quantum key distribution where statistical fluctuation is considered, however, Eve can attack it successfully with threshold detectors.

  13. UPPER COLORADO RIVER BASIN COMPACT The state of Arizona, the state of Colorado, the state of New Mexico, the state of Utah

    E-Print Network [OSTI]

    Johnson, Eric E.

    UPPER COLORADO RIVER BASIN COMPACT The state of Arizona, the state of Colorado, the state of New for the state of Arizona, Clifford H. Stone for the state of Colorado, Fred. E. Wilson for the state of New of the United States of America, have agreed, subject to the provisions of the Colorado River Compact [72

  14. State and Local Code Implementation: State Energy Officials ...

    Energy Savers [EERE]

    Energy Officials - 2014 BTO Peer Review More Documents & Publications Building Energy Codes Collaborative Technical Assistance for States Technical Assistance: Increasing Code...

  15. State Energy Program Helps States Plan and Implement Energy Efficiency...

    Energy Savers [EERE]

    to states and U.S. territories to promote energy conservation and reduce the growth of energy demand in ways that are consistent with national energy goals....

  16. State College Area High School From State College, PA Wins DOE...

    Broader source: Energy.gov (indexed) [DOE]

    State College Area High School From State College, PA Wins DOE's National Science Bowl State College Area High School From State College, PA Wins DOE's National Science Bowl...

  17. ?B-Crystallin: A Hybrid Solid-State/Solution-State NMR...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ?B-Crystallin: A Hybrid Solid-StateSolution-State NMR Investigation Reveals Structural Aspects of the Heterogeneous ?B-Crystallin: A Hybrid Solid-StateSolution-State...

  18. On the use of the double floating probe method to infer the difference between the electron and the heavy particles temperatures in an atmospheric pressure, vortex-stabilized nitrogen plasma jet

    SciTech Connect (OSTI)

    Prevosto, L., E-mail: prevosto@waycom.com.ar; Mancinelli, B. R. [Grupo de Descargas Eléctricas, Departamento Ingeniería Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, 2600 Venado Tuerto, Santa Fe (Argentina)] [Grupo de Descargas Eléctricas, Departamento Ingeniería Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, 2600 Venado Tuerto, Santa Fe (Argentina); Kelly, H. [Grupo de Descargas Eléctricas, Departamento Ingeniería Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, 2600 Venado Tuerto, Santa Fe (Argentina) [Grupo de Descargas Eléctricas, Departamento Ingeniería Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, 2600 Venado Tuerto, Santa Fe (Argentina); Instituto de Física del Plasma (CONICET), Departamento de Física, Facultad de Ciencias Exactas y Naturales (UBA) Ciudad Universitaria Pab. I, 1428 Buenos Aires (Argentina)

    2014-05-15T23:59:59.000Z

    Sweeping double probe measurements in an atmospheric pressure direct current vortex-stabilized plasma jet are reported (plasma conditions: 100 A discharge current, N{sub 2} gas flow rate of 25 Nl/min, thoriated tungsten rod-type cathode, copper anode with 5 mm inner diameter). The interpretation of the double probe characteristic was based on a generalization of the standard double floating probe formulae for non-uniform plasmas coupled to a non-equilibrium plasma composition model. Perturbations caused by the current to the probe together with collisional and thermal processes inside the probe perturbed region were taken into account. Radial values of the average electron and heavy particle temperatures as well as the electron density were obtained. The calculation of the temperature values did not require any specific assumption about a temperature relationship between different particle species. An electron temperature of 10?900 ± 900 K, a heavy particle temperature of 9300 ± 900 K, and an electron density of about 3.5 × 10{sup 22} m{sup ?3} were found at the jet centre at 3.5 mm downstream from the torch exit. Large deviations from kinetic equilibrium were found toward the outer border of the plasma jet. These results showed good agreement with those previously reported by the authors by using a single probe technique. The calculations have shown that this method is particularly useful for studying spraying-type plasma torches operated at power levels of about 15 kW.

  19. State machine replication for wide area networks

    E-Print Network [OSTI]

    Mao, Yanhua

    2010-01-01T23:59:59.000Z

    state machine . . . . . . . . . . . . . . . . . . 2.4 FLP5.3.3 P: A simple state machine . . . . . . 5.3.4performance metrics of state machine R compared to consensus

  20. Distinguishability of maximally entangled states

    E-Print Network [OSTI]

    Sibasish Ghosh; Guruprasad Kar; Anirban Roy; Debasis Sarkar

    2003-11-17T23:59:59.000Z

    In $2 \\otimes 2$, more than 2 orthogonal Bell states with single copy can never be discriminated with certainty if only local operations and classical communication (LOCC) are allowed. More than $d$ orthogonal maximally entangled states in $d \\otimed d$, which are in cannonical form, used by Bennett et. al. [Phys. Rev. Lett. 70 (1993) 1895] can never be discriminated with certainty when a single copy of the states is provided. Interestingly we show that all orthogonal maximally entangled states, which are in cannonical form, can be discriminated with certainty if and only if two copies of each of the states are provided. The highly nontrivial problem of local discrimination of $d$ or less no. of pairwise orthogonal maximally entangled states in $d \\otimes d$ (in single copy case), which are in cannonical form, is also discussed.

  1. Ancilla Approximable Quantum State Transformations

    E-Print Network [OSTI]

    Andreas Blass; Yuri Gurevich

    2014-03-30T23:59:59.000Z

    We consider the transformations of quantum states obtainable by a process of the following sort. Combine the given input state with a specially prepared initial state of an auxiliary system. Apply a unitary transformation to the combined system. Measure the state of the auxiliary subsystem. If (and only if) it is in a specified final state, consider the process successful, and take the resulting state of the original (principal) system as the result of the process. We review known information about exact realization of transformations by such a process. Then we present results about approximate realization of finite partial transformations. We consider primarily the issue of approximation to within a specified positive epsilon, but we also address the question of arbitrarily close approximation.

  2. Quantum computing with mixed states

    E-Print Network [OSTI]

    Michael Siomau; Stephan Fritzsche

    2011-01-17T23:59:59.000Z

    We discuss a model for quantum computing with initially mixed states. Although such a computer is known to be less powerful than a quantum computer operating with pure (entangled) states, it may efficiently solve some problems for which no efficient classical algorithms are known. We suggest a new implementation of quantum computation with initially mixed states in which an algorithm realization is achieved by means of optimal basis independent transformations of qubits.

  3. Quantum computing with mixed states

    E-Print Network [OSTI]

    Siomau, Michael

    2011-01-01T23:59:59.000Z

    We discuss a model for quantum computing with initially mixed states. Although such a computer is known to be less powerful than a quantum computer operating with pure (entangled) states, it may efficiently solve some problems for which no efficient classical algorithms are known. We suggest a new implementation of quantum computation with initially mixed states in which an algorithm realization is achieved by means of optimal basis independent transformations of qubits.

  4. B States at the Tevatron

    SciTech Connect (OSTI)

    Paulini, Manfred; /Carnegie Mellon U.

    2009-06-01T23:59:59.000Z

    The CDF and D0 experiments have produced a wealth of heavy flavor physics results since the beginning of RunII of the Fermilab Tevatron. They review recent measurements of B hadron states including excited B states (B**, B{sub s}**) and the B{sub c}{sup +} meson. They also summarize the discoveries of the {Sigma}{sub b} baryon states and the {Xi}{sub b}{sup -} baryon.

  5. Energy Efficient State Building Initiative

    Broader source: Energy.gov [DOE]

    In June 2008, Governor Mitch Daniels issued an executive order establishing an energy efficient state buildings initiative. The order requires the Indiana Department of Administration (DOA) to...

  6. START Program: 48 Contiguous States

    Broader source: Energy.gov [DOE]

    Overview fact sheet on the selected DOE Office of Indian Energy Strategic Technical Assistance Response Team (START) projects in the 48 contiguous states.

  7. Coherent states on the circle

    E-Print Network [OSTI]

    Chadzitaskos, G; Tolar, J

    2011-01-01T23:59:59.000Z

    We present a possible construction of coherent states on the unit circle as configuration space. In our approach the phase space is the product Z x S^1. Because of the duality of canonical coordinates and momenta, i.e. the angular variable and the integers, this formulation can also be interpreted as coherent states over an infinite periodic chain. For the construction we use the analogy with our quantization over a finite periodic chain where the phase space was Z_M x Z_M. Properties of the coherent states constructed in this way are studied and the coherent states are shown to satisfy the resolution of unity.

  8. Single electron states in polyethylene

    SciTech Connect (OSTI)

    Wang, Y. [State Key Lab. of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, No. 28 Xianning West Road, Xi'an 710049, Shaanxi (China) [State Key Lab. of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, No. 28 Xianning West Road, Xi'an 710049, Shaanxi (China); School of Physics and Complex Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4 (Ireland); MacKernan, D. [School of Physics and Complex Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4 (Ireland)] [School of Physics and Complex Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4 (Ireland); Cubero, D., E-mail: dcubero@us.es, E-mail: n.quirke@imperial.ac.uk [State Key Lab. of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, No. 28 Xianning West Road, Xi'an 710049, Shaanxi (China); Departmento de Física Aplicada I, Universidad de Sevilla, Calle Virgen de Africa 7, 41011 Seville (Spain); Coker, D. F. [School of Physics and Complex Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4 (Ireland) [School of Physics and Complex Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4 (Ireland); Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215 (United States); Quirke, N., E-mail: dcubero@us.es, E-mail: n.quirke@imperial.ac.uk [State Key Lab. of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, No. 28 Xianning West Road, Xi'an 710049, Shaanxi (China); Department of Chemistry, Imperial College, London SW7 2AY (United Kingdom)

    2014-04-21T23:59:59.000Z

    We report computer simulations of an excess electron in various structural motifs of polyethylene at room temperature, including lamellar and interfacial regions between amorphous and lamellae, as well as nanometre-sized voids. Electronic properties such as density of states, mobility edges, and mobilities are computed on the different phases using a block Lanczos algorithm. Our results suggest that the electronic density of states for a heterogeneous material can be approximated by summing the single phase density of states weighted by their corresponding volume fractions. Additionally, a quantitative connection between the localized states of the excess electron and the local atomic structure is presented.

  9. United States Department of Energy

    Office of Environmental Management (EM)

    2014, from Dorothy Riehle to Appellant. The Appellant challenges only the Exemption 4 claim, stating that Richland improperly applied Exemption 4. Appeal Letter dated December 4,...

  10. State coal profiles, January 1994

    SciTech Connect (OSTI)

    Not Available

    1994-02-02T23:59:59.000Z

    The purpose of State Coal Profiles is to provide basic information about the deposits, production, and use of coal in each of the 27 States with coal production in 1992. Although considerable information on coal has been published on a national level, there is a lack of a uniform overview for the individual States. This report is intended to help fill that gap and also to serve as a framework for more detailed studies. While focusing on coal output, State Coal Profiles shows that the coal-producing States are major users of coal, together accounting for about three-fourths of total US coal consumption in 1992. Each coal-producing State is profiled with a description of its coal deposits and a discussion of the development of its coal industry. Estimates of coal reserves in 1992 are categorized by mining method and sulfur content. Trends, patterns, and other information concerning production, number of mines, miners, productivity, mine price of coal, disposition, and consumption of coal are detailed in statistical tables for selected years from 1980 through 1992. In addition, coal`s contribution to the State`s estimated total energy consumption is given for 1991, the latest year for which data are available. A US summary of all data is provided for comparing individual States with the Nation as a whole. Sources of information are given at the end of the tables.

  11. Distributed State Space Generation of Discrete-State Stochastic Models

    E-Print Network [OSTI]

    Ciardo, Gianfranco

    of the numerical approach, since the size of the state space can easily be orders of magnitude larger than the main charts [17], and ad hoc textual languages [14], the correct logical behavior can, in principle--it makes sense to distribute the state-space principally when one has to in order to avoid paging overhead

  12. CGISS -Boise State University CGISS -Boise State University

    E-Print Network [OSTI]

    Barrash, Warren

    Michaels, P., Use of Engineering Geophysics to Investigate a Site for a Bridge Founda- tion, in FoundationsCGISS - Boise State University CGISS - Boise State University Engineering Geophysics Down-hole engineering seismology at BSU is focused on the in situ measurement of soil proper- ties. Joint inversion

  13. State DOT: PENNSYLVANIA State Report Questions on NDT Testing

    E-Print Network [OSTI]

    capacity surveys, management of load restrictions, fatigue tests and compaction control. On concreteState DOT: PENNSYLVANIA State Report Questions on NDT Testing 1. What NDT testing methods for concrete materials, concrete pavements, and overlays are you trying? PennDOT performs Falling Weight

  14. State DOT: Missouri State Report Questions on NDT Testing

    E-Print Network [OSTI]

    State DOT: Missouri State Report Questions on NDT Testing 1. What NDT testing methods for concrete maturity meter MoDOT has utilized the rebound hammer to evaluate in-place concrete when cylinder testing materials, concrete pavements, and overlays are you trying? a) Maturity Method b) Rebound Hammer c) Cover

  15. State DOT: California State Report Questions on NDT Testing

    E-Print Network [OSTI]

    test for this purpose. For concrete pavement, California has used falling weight deflectometer (FWD locations within concrete pavement. 2. In your experience, how does the reliability of NDT testing methodsState DOT: California State Report Questions on NDT Testing 1. What NDT testing methods

  16. State DOT: Louisiana State Report Questions on NDT Testing

    E-Print Network [OSTI]

    State DOT: Louisiana State Report Questions on NDT Testing 1. What NDT testing methods for concrete materials, concrete pavements, and overlays are you trying? LADOTD does not test concrete pavements or overlays non-destructively. We do use the surface resistivity meter for non-destructive testing

  17. Solid-State 55Mn NMR Spectroscopy of bis(?-oxo)dimanganese(IV) [Mn2O2(salpn)2], a Model for the Oxygen Evolving Complex in Photosystem II

    SciTech Connect (OSTI)

    Ellis, Paul D.; Sears, Jesse A.; Yang, Ping; Dupuis, Michel; Boron, Ted; Pecoraro, Vince; Stich, Troy; Britt, R. David; Lipton, Andrew S.

    2010-12-01T23:59:59.000Z

    Given the obvious global energy needs, it has become imperative to develop a catalytic process for converting water to molecular oxygen and protons. Many have sought to understand the details of photosynthesis and in particular the water splitting reaction to help in the development of the appropriate catalysis.1-3 While the scientific community has made great strides towards this goal, it has fallen short at the critical stage of the determination of the structure associated with the oxygen evolving complex (OEC) within photosystem II (PSII).4,5 Despite the existence of x-ray structures of PSII,6-8 the best data we have for the structure of the OEC comes from models derived from EPR and EXAFS measurements.9-14 This experimental situation has led to collaborations with theoreticians to enable the development of models for the structure of the OEC where the experimental observables (EXAFS and magnetic resonance parameters) serve as constraints to the theoretical calculations. Of particular interest to this study is the observation of the S1 state of the Kok cycle15 where the core of the OEC can be described as a tetranuclear manganese cluster composed of Mn4OxCa. The simplest model for the OEC can be thought of as two Mn-pairs and a Ca2+ where each Mn-pair is antiferromagnetically coupled to its partner. We utilize the term "pair" to describe the Mn atoms within the OEC with the same oxidation state, which for the S1 state is (Mn2(III, III) and Mn2(IV, IV)).16 It is unclear as to the degree of interaction between the pairs as well as the role of the Ca2+. At cryogenic temperatures the S1 state of the OEC is diamagnetic and in principle amenable to solid-state NMR experiments.

  18. Bowling Green State University Institutional

    E-Print Network [OSTI]

    Moore, Paul A.

    Bowling Green State University Institutional Animal Care and Use Committee Policy/Procedure Manual animal research at Bowling Green State University. Reading over the first three policies will provide #12;309A University Hall Bowling Green, OH 43403-0183 Phone 419-372-7716 Fax 419-372-6916 email hsrb

  19. Energy Matters in Washington State

    E-Print Network [OSTI]

    Collins, Gary S.

    Energy Matters in Washington State Energy Matters in Washington State www.energy.wsu.edu/library/ November 2009 #12;905 Plum Street SE, Building 3 P.O. Box 43169 Olympia, Washington 98504-3169 Energy University Extension Energy Program. 905 Plum Street SE, Building 3, P.O. Box 43169, Olympia, Washington

  20. Wright State University CORE Scholar

    E-Print Network [OSTI]

    Townsend, James T.

    Wright State University CORE Scholar Psychology Faculty Publications Psychology 10-1-2010 The Statistical Properties of the Survivor Interaction Contrast Joseph W. Houpt Wright State University - Main Campus, joseph.houpt@wright.edu James T. Townsend Follow this and additional works at: http://corescholar.libraries.wright