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1

Direct Imaging of Antiferromagnetic Vortex States  

NLE Websites -- All DOE Office Websites (Extended Search)

Direct Imaging of Antiferromagnetic Vortex States Print Direct Imaging of Antiferromagnetic Vortex States Print Magnetic materials are characterized by the ordering of electron spins, with nearest-neighbor spins parallel to each other in ferromagnetic (FM) materials and antiparallel to each other in antiferromagnetic (AFM) materials. As the size of a magnetic system is reduced to micron scale, it has been shown that the spins in an FM microstructure can curl around to form a magnetic vortex state. While there has been intensive activity in the study of vortex states in FM disks, there has been no direct observation of such states in an AFM microstructure, although theory predicts many interesting and unique properties for the AFM vortex state. Recently, a research team from Berkeley, Korea, and China has taken the first direct image of an AFM vortex in multilayered magnetic disk structures using x-ray magnetic linear dichroism (XMLD) and photoemission electron microscopy (PEEM) at ALS Beamlines 4.0.2 and 11.0.1 , respectively. The experiments observed two types of AFM vortices, one of which has no analogue in FM vortices.

2

Direct Imaging of Antiferromagnetic Vortex States  

NLE Websites -- All DOE Office Websites (Extended Search)

Direct Imaging of Antiferromagnetic Vortex States Print Direct Imaging of Antiferromagnetic Vortex States Print Magnetic materials are characterized by the ordering of electron spins, with nearest-neighbor spins parallel to each other in ferromagnetic (FM) materials and antiparallel to each other in antiferromagnetic (AFM) materials. As the size of a magnetic system is reduced to micron scale, it has been shown that the spins in an FM microstructure can curl around to form a magnetic vortex state. While there has been intensive activity in the study of vortex states in FM disks, there has been no direct observation of such states in an AFM microstructure, although theory predicts many interesting and unique properties for the AFM vortex state. Recently, a research team from Berkeley, Korea, and China has taken the first direct image of an AFM vortex in multilayered magnetic disk structures using x-ray magnetic linear dichroism (XMLD) and photoemission electron microscopy (PEEM) at ALS Beamlines 4.0.2 and 11.0.1 , respectively. The experiments observed two types of AFM vortices, one of which has no analogue in FM vortices.

3

Direct Imaging of Antiferromagnetic Vortex States  

NLE Websites -- All DOE Office Websites (Extended Search)

Direct Imaging of Antiferromagnetic Vortex States Print Direct Imaging of Antiferromagnetic Vortex States Print Magnetic materials are characterized by the ordering of electron spins, with nearest-neighbor spins parallel to each other in ferromagnetic (FM) materials and antiparallel to each other in antiferromagnetic (AFM) materials. As the size of a magnetic system is reduced to micron scale, it has been shown that the spins in an FM microstructure can curl around to form a magnetic vortex state. While there has been intensive activity in the study of vortex states in FM disks, there has been no direct observation of such states in an AFM microstructure, although theory predicts many interesting and unique properties for the AFM vortex state. Recently, a research team from Berkeley, Korea, and China has taken the first direct image of an AFM vortex in multilayered magnetic disk structures using x-ray magnetic linear dichroism (XMLD) and photoemission electron microscopy (PEEM) at ALS Beamlines 4.0.2 and 11.0.1 , respectively. The experiments observed two types of AFM vortices, one of which has no analogue in FM vortices.

4

Antiferromagnetic state in bilayer graphene  

Science Journals Connector (OSTI)

Motivated by the recent experiment of Velasco Jr. et al. [J. Velasco Jr. et al., Nat. Nanotechnology 7, 156 (2012)], we develop a mean-field theory of the interaction-induced antiferromagnetic (AF) state in bilayer graphene at charge neutrality point at arbitrary perpendicular magnetic field B. We demonstrate that the AF state can persist at all B. At higher B, the state continuously crosses over to the AF phase of the ?=0 quantum Hall ferromagnet, recently argued to be realized in the insulating ?=0 state. The mean-field quasiparticle gap is finite at B=0 and grows with increasing B, becoming quasilinear in the quantum Hall regime, in accord with the reported behavior of the transport gap. By adjusting the two free parameters of the model, we obtain a simultaneous quantitative agreement between the experimental and theoretical values of the key parameters of the gap dependence—its zero-field value and slope at higher fields. Our findings suggest that the insulating state observed in bilayer graphene in Ref. 1 is antiferromagnetic (canted, once the Zeeman effect is taken into account) at all magnetic fields.

Maxim Kharitonov

2012-11-30T23:59:59.000Z

5

Lower pseudogap phase of Mott insulators: A spin/vortex liquid state  

Science Journals Connector (OSTI)

The pseudogap phase is considered to be a new state of matter in the phase string model of the doped Mott insulator, which is composed of two distinct regimes known as the upper and lower pseudogap phases, respectively. The former corresponds to the formation of spin-singlet pairing, the magnetic characterizations of which have been recently studied [Phys. Rev. B 72, 104520 (2005)]. The latter, as a low-temperature regime of the pseudogap phase, is systematically explored in this work, which is characterized by the formation of the Cooper pair amplitude and described by a generalized Ginzburg-Landau theory. Elementary excitation in this phase is a charge-neutral object carrying spin-1?2 and locking with a supercurrent vortex, known as a spinon-vortex composite. Such a lower pseudogap phase can be regarded as a vortex liquid state due to the presence of free spinon vortices. Here thermally excited spinon vortices destroy the phase coherence and are responsible for the nontrivial Nernst effect and diamagnetism. The transport entropy and core energy associated with a spinon vortex are determined by the spin degrees of freedom. Such a spontaneous vortex liquid phase can be also considered as a spin liquid with a finite correlation length and gaped S=1?2 excitations, where a resonancelike nonpropagating spin mode emerges at the antiferromagnetic wavevector (?,?) with a doping-dependent characteristic energy. The superconducting phase is closely related to the lower pseudogap phase by a topological transition with spinon vortices and antivortices forming bound pairs and the emergence of fermionic quasiparticles as holon-spinon-vortex bound objects. A quantitative phase diagram in the parameter space of doping, temperature, and magnetic field is determined. Comparisons with experiments are also made.

Zheng-Yu Weng and Xiao-Liang Qi

2006-10-26T23:59:59.000Z

6

Thermodynamic properties of the fcc Ising antiferromagnet obtained from precision density of states calculations  

E-Print Network (OSTI)

Thermodynamic properties of the fcc Ising antiferromagnet obtained from precision density of states May 2006 We calculate the density of states for the face-centered-cubic fcc Ising model with nearest of the fcc Ising antiferromagnet has been a long-standing problem in statistical physics, dating back to1

Ryan, Dominic

7

Magnetization reversal via single and double vortex states in submicron Permalloy ellipses P. Vavassori,1  

E-Print Network (OSTI)

Magnetization reversal via single and double vortex states in submicron Permalloy ellipses P University, Ithaca, New York, USA Received December 5, 2003; published 3 June 2004 The magnetization reversal of the magnetic field and to occur via the formation of one or two vortices; the one vortex state is nucleated

Metlushko, Vitali

8

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

E-Print Network (OSTI)

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...

Kim, S.; Hu, Chia-Ren; Andrews, MJ.

2004-01-01T23:59:59.000Z

9

Symmetry breaking in the formation of magnetic vortex states in a permalloy nanodisk  

E-Print Network (OSTI)

structure of magnetic vortex cores. Science 298, 6. Fischer,Magnetic Material Center, National Institute for Materials Science (Magnetic vortex core observation in circular dots of Permalloy. Science

Im, Mi-Young

2014-01-01T23:59:59.000Z

10

Vortex states in a binary mixture of Bose-Einstein condensates  

Science Journals Connector (OSTI)

The vortex configurations in the Bose-Einstein condensate of a mixture of two different spin states |F=1,mf=-1? and |2,1? of 87Rb atoms corresponding to the recent experiments by Matthews et al. [Phys. Rev. Lett. 83, 2498 (1999)] are considered in the framework of the Thomas-Fermi approximation as functions of N2/N1, where N1 is the number of atoms in the state |1,-1? and N2 in the state |2,1?. Ranges of this ratio are determined within which the various configurations of the binary condensate are stable.

S. T. Chui; V. N. Ryzhov; E. E. Tareyeva

2001-01-11T23:59:59.000Z

11

Diluted Graphene Antiferromagnet  

Science Journals Connector (OSTI)

We study RKKY interactions between local magnetic moments for both doped and undoped graphene. In the former case interactions for moments located on definite sublattices fall off as 1/R2, whereas for those placed at interstitial sites they decay as 1/R3. The interactions are primarily (anti)ferromagnetic for moments on (opposite) equivalent sublattices, suggesting that at low temperature dilute magnetic moments embedded in graphene can order into a state analogous to that of a dilute antiferromagnet. In the undoped case we find no net magnetic moment in the ground state, and demonstrate numerically this effect for ribbons, suggesting the possibility of an unusual spin-transfer device.

L. Brey; H. A. Fertig; S. Das Sarma

2007-09-12T23:59:59.000Z

12

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

SciTech Connect

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.

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

1993-11-01T23:59:59.000Z

13

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

E-Print Network (OSTI)

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

Daniel Domínguez; Jorge V. José

1994-07-11T23:59:59.000Z

14

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

E-Print Network (OSTI)

magnetic vortex. The vortex-core diameter is controlled by competing magnetic energy contributions. For 20-nm-thick Fe dots, the values of the critical diameter (58-60 nm) and the vortex core (16-19 nm) are in very good agreement between the different...

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

15

High-field magnetic ground state in S=12 kagome lattice antiferromagnet ZnCu3(OH)6Cl2  

Science Journals Connector (OSTI)

Herbertsmithite ZnCu3(OH)6Cl2 is a kagome lattice antiferromagnet with spin-1/2 and has been demonstrated to be a likely candidate of spin liquid by a number of recent experiments. The high-field magnetization of the kagome lattice is complicated due to the presence of a few percent of extra Cu impurities sitting on the interlayer metallic sites. To determine the magnetic ground state of the kagome lattice, we measured the magnetization of a single crystalline ZnCu3(OH)6Cl2 using torque magnetometry down to the base temperatures 20 mK in intense magnetic field as high as 31 T. The high-field intrinsic magnetization from the kagome lattice turns out to be linear with magnetic field, and the magnetic susceptibility is independent of temperature at 20mK?T?5 K. Moreover, below 2 K, several field-induced anomalies are observed in between 7 T and 15 T.

Tomoya Asaba; Tian-Heng Han; B. J. Lawson; F. Yu; C. Tinsman; Z. Xiang; G. Li; Young S. Lee; Lu Li

2014-08-18T23:59:59.000Z

16

E-Print Network 3.0 - antiferromagnetic spin correlations Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

decay algebrically. For the q-state antiferromagnetic Potts model... antiferromagnetic Ising models, with an ... Source: Ecole Polytechnique, Centre de mathmatiques Collection:...

17

Calorimetric study of the transitions between the different vortex states in YBa{sub 2}Cu{sub 3}O{sub 7}.  

SciTech Connect

We have studied the vortex phase diagram of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) in very strong magnetic field (0-26 Tesla) by a.c. calorimetry. We describe the anomalies associated with the transitions between the different vortex states (solid, liquid, and glass), with special emphasis on the first order flux lattice melting.

Bouquet, F.; Calemczuk, R.; Crabtree, G. W.; Erb, A.; Fisher, R. A.; Junod, A.; Kwok, W. K.; Marcenat, C.; Phillips, N. E.; Roulin, M.; Schilling, A.; Welp, U.

1999-08-17T23:59:59.000Z

18

Temperature dependence of vortex charges in high-temperature superconductors  

Science Journals Connector (OSTI)

Using a model Hamiltonian with d-wave superconductivity and competing antiferromagnetic (AF) interactions, the temperature (T) dependence of the vortex charge in high-Tc superconductors is investigated by numerically solving the Bogoliubov–de Gennes equations. The strength of the induced AF order inside the vortex core is T dependent. The vortex charge could be negative when the AF order with sufficient strength is present at low temperatures. At higher temperatures, the AF order may be completely suppressed and the vortex charge becomes positive. A first-order-like transition in the T-dependent vortex charge is seen near the critical temperature TAF. For an underdoped sample, the spatial profiles of the induced spin-density wave and the charge-density wave orders could have stripelike structures at TTs. As a result, a vortex charge discontinuity occurs at Ts.

Yan Chen; Z. D. Wang; C. S. Ting

2003-06-03T23:59:59.000Z

19

Piezo-antiferromagnetic effect of sawtooth-like graphene nanoribbons  

SciTech Connect

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.

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

20

Triangular antiferromagnetic Ising model  

Science Journals Connector (OSTI)

We solve the Ising problem on a triangular lattice with anisotropic interactions. Special consideration is given to the antiferromagnetic case. It is found that no phase transition exists if J1=J2=J3|J1|. Physical arguments to explain this behavior are also presented.

T. P. Eggarter

1975-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Quantum Kinematics of Bosonic Vortex Loops  

SciTech Connect

Poisson structure for vortex filaments (loops and arcs) in 2D ideal incompressible fluid is analyzed in detail. Canonical coordinates and momenta on coadjoint orbits of the area-preserving diffeomorphism group, associated with such vortices, are found. The quantum space of states in the simplest case of ''bosonic'' vortex loops is built within a geometric quantization approach to the description of a quantum fluid. Fock-like structure and non-local creation and annihilation operators of quantum vortex filaments are introduced.

Goldin, G.A.; Owczarek, R.; Sharp, D.H.

1999-05-06T23:59:59.000Z

22

Antiferromagnetic domain size and exchange bias  

E-Print Network (OSTI)

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...

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

2008-01-01T23:59:59.000Z

23

Magnetic properties of layered antiferromagnets  

Science Journals Connector (OSTI)

Magnetic properties of layered antiferromagnets have been studied using correlated effective field (CEF) theory developed by M. E. Lines. This theory goes beyond mean-field theory and correctly reproduces the experimental results. The theory is used here to interpret the magnetic order parameter and the susceptibilities of the FePS3 compound, which is a layered antiferromagnet with a marked Ising anisotropy.

Ibha Chatterjee

1995-02-01T23:59:59.000Z

24

Antiferromagnetism in Narrow-Band Solids  

Science Journals Connector (OSTI)

The single-band Hubbard Hamiltonian is examined in the limit of bandwidth much less than intraatomic Coulomb interaction of electrons. We make use of the canonical transformation and "spectral decomposition" of the electron creation operators proposed by Harris and Lange to write down a Green's function which describes electrons in the lower of the split bands of Hubbard's solution. The equation of motion is solved using the moment-conserving decoupling approximation of Tahir-Kheli and Jarrett. We find within our approximation that it is impossible to have an antiferromagnetic state for other than one electron per site. To remedy this defect of the single-band model, we investigate a simplified two-band model in the limit of intra-atomic Coulomb and exchange interaction much greater than the bandwidth, and find that antiferromagnetism is possible for the two nearly half-filled bands. We also discuss effects of the antiferromagnetic ordering on the conductivity in our simplified model and discuss applicability of the theory to real transition metals and transition-metal oxides.

J. B. Sokoloff

1970-02-01T23:59:59.000Z

25

Triangular Ising antiferromagnet in a staggered field  

Science Journals Connector (OSTI)

We study the equilibrium properties of the nearest-neighbor Ising antiferromagnet on a triangular lattice in the presence of a staggered field conjugate to one of the degenerate ground states. Using a mapping of the ground states of the model without the staggered field to dimer coverings on the dual lattice, we classify the ground states into sectors specified by the number of “strings.” We show that the effect of the staggered field is to generate long-range interactions between strings. In the limiting case of the antiferromagnetic coupling constant J becoming infinitely large, we prove the existence of a phase transition in this system and obtain a finite lower bound for the transition temperature. For finite J, we study the equilibrium properties of the system using Monte Carlo simulations with three different dynamics. We find that in all the three cases, equilibration times for low-field values increase rapidly with system size at low temperatures. Due to this difficulty in equilibrating sufficiently large systems at low temperatures, our finite-size scaling analysis of the numerical results does not permit a definite conclusion about the existence of a phase transition for finite values of J. A surprising feature in the system is the fact that unlike usual glassy systems, a zero-temperature quench almost always leads to the ground state, while a slow cooling does not.

Abhishek Dhar; Pinaki Chaudhuri; Chandan Dasgupta

2000-03-01T23:59:59.000Z

26

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

NLE Websites -- All DOE Office Websites (Extended Search)

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

27

Improved vortex reactor system  

DOE Patents (OSTI)

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.

Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO)

1995-01-01T23:59:59.000Z

28

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

E-Print Network (OSTI)

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.

A. A. Kokin; V. A. Kokin

2008-12-01T23:59:59.000Z

29

Dynamic decay of a single vortex into vortex-antivortex pairs  

SciTech Connect

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.

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

30

E-Print Network 3.0 - antiferromagnetic spin fluctuations Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

H. T. Diepa... antiferromagnetic FCC films by Monte Carlo simulation. In the case of Ising spin model, we show that the spin... the work by Haas where he stated that in...

31

ENERGY LEVEL SPECTROSCOPY OF A BOUND VORTEX-ANTIVORTEX PAIR  

E-Print Network (OSTI)

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

Wallraff, Andreas

32

Improved vortex reactor system  

DOE Patents (OSTI)

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.

Diebold, J.P.; Scahill, J.W.

1995-05-09T23:59:59.000Z

33

Monte Carlo study of a compressible Ising antiferromagnet on a triangular lattice Lei Gu and Bulbul Chakraborty  

E-Print Network (OSTI)

ARTICLES Monte Carlo study of a compressible Ising antiferromagnet on a triangular lattice Lei Gu the compressible antiferromagnetic Ising Model on a triangular lattice using Monte Carlo simulations. It is found broken symmetries: the Ising symmetry and a three-state Potts symmetry characteristic of the triangular

Garrido, Pedro L.

34

Stripe Domains and First-Order Phase Transition in the Vortex Matter of Anisotropic High-Temperature Superconductors  

E-Print Network (OSTI)

Stripe Domains and First-Order Phase Transition in the Vortex Matter of Anisotropic High-Temperature temperature superconductor and reveal a sharp transition in the state of this phase resulting in regular that can subsequently melt at high temperatures to a vortex liquid, a pinned vortex glassy state that can

Alexei, Koshelev

35

Vortex Hydro Energy LLC | Open Energy Information  

Open Energy Info (EERE)

Hydro Energy LLC Hydro Energy LLC Jump to: navigation, search Name Vortex Hydro Energy LLC Address 4870 West Clark Rd Suite 108 Place Ypsilanti Zip 48197 Sector Marine and Hydrokinetic Phone number 734.971.4020 Website http://www.vortexhydroenergy.c Region United States LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This company is listed in the Marine and Hydrokinetic Technology Database. This company is involved in the following MHK Projects: Marine Hydrodynamics Laboratory at the University of Michigan This company is involved in the following MHK Technologies: Vortex Induced Vibrations Aquatic Clean Energy VIVACE This article is a stub. You can help OpenEI by expanding it. Retrieved from "http://en.openei.org/w/index.php?title=Vortex_Hydro_Energy_LLC&oldid=678497

36

Adiabatic Preparation of a Heisenberg Antiferromagnet Using an Optical Superlattice  

E-Print Network (OSTI)

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.

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

2011-11-06T23:59:59.000Z

37

Adiabatic preparation of a Heisenberg antiferromagnet using an optical superlattice  

E-Print Network (OSTI)

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.

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

2011-01-01T23:59:59.000Z

38

Field dependence of the vortex structure in d-wave and s-wave superconductors  

Science Journals Connector (OSTI)

We study the vortex structure and its field dependence within the framework of the quasiclassical Eilenberger theory to find the difference between the dx2-y2- and s-wave pairings. We clarify the effect of the dx2-y2-wave nature and the vortex lattice effect on the vortex structure of the pair potential, the internal field and the local density of states. The dx2-y2-wave pairing introduces a fourfold-symmetric structure around each vortex core. With increasing field, their contribution becomes significant to the whole structure of the vortex lattice state, depending on the vortex lattice’s configuration. It is reflected in the form factor of the internal field, which may be detected by small-angle neutron scattering, or the resonance line shape of muon spin resonance and NMR experiments. We also study the induced s- and dxy-wave components around the vortex in dx2-y2-wave superconductors.

Masanori Ichioka; Akiko Hasegawa; Kazushige Machida

1999-04-01T23:59:59.000Z

39

Vortex Characterization for Engineering Applications  

SciTech Connect

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.

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

2008-01-30T23:59:59.000Z

40

Nested Cluster Algorithm for Frustrated Quantum Antiferromagnets  

E-Print Network (OSTI)

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.

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

2008-03-25T23:59:59.000Z

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Vortex motion in Josephson-junction arrays near f=0 and f=1/2  

Science Journals Connector (OSTI)

We study vortex motion in two-dimensional Josephson arrays at magnetic fields near zero and one-half flux quanta per plaquette (f=0 and f=1/2). The array is modeled as a network of resistively and capacitively shunted Josephson junctions at temperature T=0. Calculations are carried out over a range of the McCumber-Stewart junction damping parameter ?. Near both f=0 and f=1/2, the I-V characteristics exhibit two critical currents, Ic1(f) and Ic2(f), representing the critical current for depinning a single vortex, and for depinning the entire ground-state phase configuration. Near f=0, single vortex motion just above Ic1(0) leads to Josephson-like voltage oscillations. The motion of the vortex is seemingly overdamped (i.e., nonhysteretic) even when the individual junction parameters are highly underdamped, in agreement with experiments. At sufficiently large ?, and sufficiently high vortex velocity, the vortex breaks up into a row of resistively switched junctions perpendicular to the current. Near f=1/2, the vortex potential, and corresponding vortex trajectories, are more complicated than near f=0. Nevertheless, the vortex is still ‘‘overdamped’’ even when the individual junctions are highly underdamped, and there is still row-switching behavior at large values of ?. A high-energy vortex in a very underdamped array tends to generate resistively switched rows rather than to move ballistically. Some possible explanations for this behavior are discussed.

Wenbin Yu; K. H. Lee; D. Stroud

1993-03-01T23:59:59.000Z

42

E-Print Network 3.0 - alternating heisenberg antiferromagnetic...  

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in a diluted fcc antiferromagnet Carsten Wengel... on a Monte Carlo study of a diluted Ising antiferromagnet on a fcc lattice. This is a typical model example... of a highly...

43

Free Energy of the Antiferromagnetic Linear Chain  

Science Journals Connector (OSTI)

Rigorous upper and lower bounds for the free energy of the antiferromagnetic Heisenberg linear chain are obtained from general convexity properties of the free energy. The lower bound is here derived; the upper bound has been obtained previously by Bulaevskii. Both are compared with the calculations of Bonner and Fisher for finite chains.

Robert B. Griffiths

1964-11-02T23:59:59.000Z

44

Strange correlations in spin-1 Heisenberg antiferromagnets  

E-Print Network (OSTI)

We study the behavior of the recently proposed "strange correlator" [Phys. Rev. Lett. {\\bf 112}, 247202 (2014)] in spin-1 Heisenberg antiferromagnetic chains with uniaxial single-ion anisotropy. Using projective quantum Monte Carlo, we are able to directly access the strange correlator in a variety of phases, as well as to examine its critical behavior at the quantum phase transition between trivial and non-trivial symmetry protected topological phases. After finding the expected long-range behavior in these two symmetry conserving phases, we go on to verify the topological nature of two-leg and three-leg spin-1 Heisenberg antiferromagnetic ladders. This demonstrates the power of the strange correlator in distinguishing between trivial and non-trivial symmetry protected topological phases.

Wierschem, Keola

2014-01-01T23:59:59.000Z

45

Vortex lines and transitions in superfluid hydrodynamics  

Science Journals Connector (OSTI)

...Preface to Vortices, dislocations, and line singularities in partial differential equations...Leslie and J. R. Ockendon. Vortex lines and transitions in superfluid hydrodynamics...nature and the motion of qunatized vortex lines. This paper illustrates the transitions...

1997-01-01T23:59:59.000Z

46

Gravity waves from vortex dipoles and jets  

E-Print Network (OSTI)

The dissertation first investigates gravity wave generation and propagation from jets within idealized vortex dipoles using a nonhydrostatic mesoscale model. Several initially balanced and localized jets induced by vortex dipoles are examined here...

Wang, Shuguang

2009-05-15T23:59:59.000Z

47

Delta doping of ferromagnetism in antiferromagnetic manganite superlattices.  

SciTech Connect

We demonstrate that delta doping can be used to create a dimensionally confined region of metallic ferromagnetism in an antiferromagnetic (AFM) manganite host, without introducing any explicit disorder due to dopants or frustration of spins. Theoretical consideration of these additional carriers shows that they cause a local enhancement of ferromagnetic double exchange with respect to AFM superexchange, resulting in local canting of the AFM spins. This leads to a highly modulated magnetization, as measured by polarized neutron reflectometry. The spatial modulation of the canting is related to the spreading of charge from the doped layer and establishes a fundamental length scale for charge transfer, transformation of orbital occupancy, and magnetic order in these manganites. Furthermore, we confirm the existence of the canted, AFM state as was predicted by de Gennes [Phys. Rev. 118 141 (1960)] but had remained elusive.

Santos, T. S.; Kirby, B. J.; Kumar, S.; May, S. J.; Borchers, J. A.; Maranville, B. B.; Zarestky, J.; te Velthuis, S. G. E.; van den Brink, J.; Bhattacharya, A. (Center for Nanoscale Materials); ( MSD); (NIST); (IFW Dresden); (Drexel Univ.); (Iowa State Univ.)

2011-01-01T23:59:59.000Z

48

Vortex Structure in Charged Condensate  

E-Print Network (OSTI)

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.

Gabadadze, Gregory

2009-01-01T23:59:59.000Z

49

Vortex Structure in Charged Condensate  

E-Print Network (OSTI)

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.

Gregory Gabadadze; Rachel A. Rosen

2009-05-14T23:59:59.000Z

50

Argonne CNM Highlight: Exploring the limits of antiferromagnetism in  

NLE Websites -- All DOE Office Websites (Extended Search)

spin structure of manganese monolayer ; (Top) Schematic of the spin structure of the Mn monolayer on W(110) (6-nm repeat structure). (a) Topography and (b) differential conductance at 40 K. (Inset) High-resolution topographic data taken with a spin-sensitive tip; stripe contrast is related to the degree of antiferromagnetic order. Exploring the limits of antiferromagnetism in nanostructured materials Researchers in the Electronic & Magnetic Materials & Devices Group and at Politecnico di Milano in Italy explored the limits of antiferromagnetism in a nanostructured material for the first time, measuring the temperature required to support antiferromagnetic order in atomic monolayers of manganese on tungsten as the dimensions of the structures are reduced.

51

E-Print Network 3.0 - antiferromagnetically coupled perpendicular...  

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of c EDP Sciences Article published... et al. 11. This case of a two-sublattice Ising antiferromagnet exchange coupled to a ferromagnet... that the free energy without...

52

E-Print Network 3.0 - antiferromagnetically coupled multilayers...  

NLE Websites -- All DOE Office Websites (Extended Search)

of c EDP Sciences Article published... et al. 11. This case of a two-sublattice Ising antiferromagnet exchange coupled to a ferromagnet... that the free energy without...

53

Flame–vortex interaction in a reacting vortex ring  

Science Journals Connector (OSTI)

Direct numerical simulations are used to study the flame–vortex interaction in a laminar reacting vortex ring. The chemical reaction occurs by a one-step Arrhenius-type reaction that mimics the combustion of typical hydrocarbon and air. The ring is generated by an axisymmetric jet that is impulsed to emit a cold fuel through a nozzle. The fuel enters a quiescent ambient at a much higher temperature. By adjusting the ratio of the ambient and fuel temperatures the ignition either occurs during the formation or post-formation phase of the ring. When ignition occurs during the formation phase of the ring the bulk of combustion is by a flame at the front of the vortex bubble. When ignition is delayed until after the formation phase most of the reaction occurs inside the vortex ring. It is found that premixing the fuel and the oxidizer enhances the amount of product formation. The heat released from the reaction significantly affects production redistribution and diffusion of the vorticity throughout the field. The results of the simulations also reveal that the heat of reaction affects the strain rate fields differently depending on when the ignition of the ring occurs.

J. S. Hewett; C. K. Madnia

1998-01-01T23:59:59.000Z

54

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

SciTech Connect

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.

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

55

E-Print Network 3.0 - antiferromagnetic noise correlations Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

. . , correlated vertically, the energy of the antiferromagnetic chain is increased... Ising antiferromagnets have exact RPM when evolving from a large field, but not when started...

56

E-Print Network 3.0 - antiferromagnet magnetic excitations Sample...  

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anisotropic uniaxial antiferromagnet with a magnetic phase... . The transition to the Ising-like antiferromagnetic phase is possible ... Source: Ecole Polytechnique, Centre de...

57

E-Print Network 3.0 - antiferromagnet er5ir4si10 single Sample...  

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in a diluted fcc antiferromagnet Carsten Wengel... on a Monte Carlo study of a diluted Ising antiferromagnet on a fcc ... Source: Henley, Christopher L. - Department of Physics,...

58

E-Print Network 3.0 - antiferromagnetic spin waves Sample Search...  

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model, it is energetically favourable for two neighbouring spins... antiferromagnetic Ising models, with an antiferromagnetic four spin coupling (L 0). The unstable fixed...

59

Ferromagnetism at the interfaces of antiferromagnetic FeRh epilayers  

SciTech Connect

The nanoscale magnetic structure of FeRh epilayers has been studied by polarized neutron reflectometry. Epitaxial films with a nominal thickness of 500 {angstrom} were grown on MgO (001) substrates via molecular-beam epitaxy and capped with 20 {angstrom} of MgO. The FeRh films show a clear transition from the antiferromagnetic (AF) state to the ferromagnetic (FM) state with increasing temperature. Surprisingly the films possess a FM moment even at a temperature 80 K below the AF-FM transition temperature of the film. We have quantified the magnitude and spatial extent of this FM moment, which is confined to within {approx}60-80 {angstrom} of the FeRh near the top and bottom interfaces. These interfacial FM layers account for the unusual effects previously observed in films with thickness <100 {angstrom}. Given the delicate energy balance between the AF and FM ground states we suggest a metastable FM state resides near to the interface within an AF matrix. The length scale over which the FM region resides is consistent with the strained regions of the film.

Fan, P.; Arena, D.; Kinane, C.J.; Charlton, T.R.; Dorner, R.; Ali, M.; de Vries, A. de.; Brydson, R.M.D.; Marrows, C.H.; Hickey, B.J.; Tanner, B.K.; Nisbet, G.; and Langridge, S.

2010-07-15T23:59:59.000Z

60

Broken symmetry and (1/2 statistics of spinons in (2+1)-dimensional antiferromagnets  

Science Journals Connector (OSTI)

We consider the Gutzwiller-projected Hofstadter-Slater determinant as a resonating-valence-bond wave function in a (2+1)-dimensional antiferromagnet. A strong case is made that spinons in the spin liquid state obey (1/2 statistics when a mass gap is present. We arrive at this conclusion from an effective continuum limit gauge theory. When a mass gap opens up, the parity symmetry is spontaneously broken resulting in twofold degeneracy of the ground state. The picture is consistent with that of the fractional quantum Hall state advocated by Laughlin.

Z. Zou

1989-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Integrated multi vector vortex beam generator  

E-Print Network (OSTI)

A novel method to generate and manipulate vector vortex beams in an integrated, ring resonator based geometry is proposed. We show numerically that a ring resonator, with an appropriate grating, addressed by a vertically displaced access waveguide emits a complex optical field. The emitted beam possesses a specific polarization topology, and consequently a transverse intensity profile and orbital angular momentum. We propose a combination of several concentric ring resonators, addressed with different bus guides, to generate arbitrary orbital angular momentum qudit states, which could potentially be used for classical and quantum communications. Finally, we demonstrate numerically that this device works as an orbital angular momentum sorter with an average cross-talk of -10 dB between different orbital angular momentum channels.

Sebastian A. Schulz; Taras Machula; Ebrahim Karimi; Robert W. Boyd

2013-03-19T23:59:59.000Z

62

Fragile antiferromagnetism in the heavy-fermion compound YbBiPt  

SciTech Connect

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.

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

63

Spin-Chirality-Driven Ferroelectricity on a Perfect Triangular Lattice Antiferromagnet  

SciTech Connect

Magnetic eld (B) variation of the electrical polarization Pc ( c) of the perfect triangular lattice antiferromagnet RbFe(MoO4)2 is examined up to the saturation point of the magnetization for B ? c. Pc is observed only in phases for which chirality is predicted in the in-plane magnetic structures. No strong anomaly is observed in Pc at the eld at which the spin modulation along the c axis, and hence the spin helicity, exhibits a discontinuity to the commensurate state. These results indicate that the ferroelectricity in this compound originates predominantly from the spin chirality, the explanation of which would require a new mechanism for magnetoferroelectricity. The obtained eld-temperature phase diagrams of ferroelectricity well agree with those theoretically predicted for the spin chirality of a Heisenberg spin triangular lattice antiferromagnet.

Mitamura, H. [University of Tokyo, Japan; Watanuki, R. [Yokohama National University; Kaneko, Koji [Japan Atomic Energy Agency (JAEA); Onozaki, N. [Yokohama National University; Amou, Y. [Yokohama National University; Kittaka, S. [University of Tokyo, Japan; Kobayashi, Riki [ORNL; Shimura, Y. [University of Tokyo, Japan; Yamamoto, I. [Yokohama National University; Suzuki, K. [Yokohama National University; Chi, Songxue [ORNL; Sakakibara, T. [University of Tokyo, Japan

2014-01-01T23:59:59.000Z

64

Vortex molecules in Bose-Einstein condensates  

E-Print Network (OSTI)

Stable vortex dimers are known to exist in coherently coupled two component Bose-Einstein condensates (BECs). We construct stable vortex trimers in three component BECs and find that the shape can be controlled by changing the internal coherent (Rabi) couplings. Stable vortex N-omers are also constructed in coherently coupled N-component BECs. We classify all possible N-omers in terms of the mathematical graph theory. Next, we study effects of the Rabi coupling in vortex lattices in two-component BECs. We find how the vortex lattices without the Rabi coupling known before are connected to the Abrikosov lattice of integer vortices with increasing the Rabi coupling. In this process, vortex dimers change their partners in various ways at large couplings. We then find that the Abrikosov lattices are robust in three-component BECs.

Muneto Nitta; Minoru Eto; Mattia Cipriani

2013-07-16T23:59:59.000Z

65

Reconnection of vortex filaments and Kolmogorov spectrum  

E-Print Network (OSTI)

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...

Nemirovskii, Sergey K

2014-01-01T23:59:59.000Z

66

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...

67

Ferromagnetism and antiferromagnetism in the quantum Ising model  

Science Journals Connector (OSTI)

The Ising model in a magnetic field is studied in its quantum version. The particular realization of the renormalization group proposed gives both the ferromagnetic and antiferromagnetic fixed points. The critical exponents are obtained in a very simple analytical way.

L. N. Epele; H. Fanchiotti; C. A. García Canal

1981-07-01T23:59:59.000Z

68

Giant magnetic effects and oscillations in antiferromagnetic Josephson weak links  

SciTech Connect

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.

Gorkov, L.; Kresin, Vladimir

2001-04-01T23:59:59.000Z

69

Shape-induced phenomena in finite-size antiferromagnets  

Science Journals Connector (OSTI)

It is common knowledge that the direction of the easy axis in a finite-size ferromagnetic sample is controlled by its shape. In the present paper we show that a similar phenomenon should be observed in compensated antiferromagnets with strong magnetoelastic coupling. The destressing energy which originates from the long-range magnetoelastic forces is analogous to the demagnetization energy in ferromagnetic materials and is responsible for the formation of the equilibrium domain structure and the anisotropy of macroscopic magnetic properties. In particular, the crystal shape may be a source of additional uniaxial magnetic anisotropy which removes the degeneracy of the antiferromagnetic vector or the artificial fourth-order anisotropy in the case of a square cross-section sample. In the special case of antiferromagnetic nanopillars, shape-induced anisotropy can be substantially enhanced due to lattice mismatch with the substrate. These effects can be detected by magnetic rotational torque and antiferromagnetic resonance measurements.

Helen V. Gomonay and Vadim M. Loktev

2007-05-25T23:59:59.000Z

70

The idea of vortex energy  

E-Print Network (OSTI)

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.

V. E. Shapiro

2011-09-22T23:59:59.000Z

71

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print 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 the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

72

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print 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 the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

73

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic 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 thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

74

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print 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 the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

75

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print 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 the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

76

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print 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 the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

77

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print 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 the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

78

Stability of vortex solitons in a photorefractive optical lattice  

E-Print Network (OSTI)

://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

Yang, Jianke

79

Quantum Skyrmions and the Destruction of Antiferromagnetic Order in High-Temperature Superconductors  

E-Print Network (OSTI)

A continuous field theory which describes the process of doping in high-T$_c$ superconductors of the YBCO-type is presented. It is shown that the introduction of dopants produces the creation of skyrmion topological excitations on the antiferromagnetic background. The energy of these excitations is evaluated. Destruction of the N\\'eel ground state occurs for a critical value $\\delta_C$ of the doping parameter for which the skyrmion energy vanishes. We evaluate this at zero temperature, obtaining $\\delta_C = 0.39 \\pm 0.03$ which agrees with the experimental value $\\delta_C^{exp} = 0.41 \\pm 0.02$.

E. C. Marino

1998-05-27T23:59:59.000Z

80

Ferroelectric charge order stabilized by antiferromagnetism in multiferroic LuFe2O4  

Science Journals Connector (OSTI)

Neutron diffraction measurements on multiferroic LuFe2O4 show changes in the antiferromagnetic (AFM) structure characterized by wave vector q=(131312) as a function of electric field cooling procedures. The increase of intensity from all magnetic domains and the decrease in the two-dimensional (2D) magnetic order observed below the Néel temperature are indicative of increased ferroelectric charge order (CO). The AFM order changes the dynamics of the CO state, and stabilizes it. It is determined that the increase in electric polarization observed at the magnetic ordering temperature is due to a transition from paramagnetic 2D charge order to AFM three-dimensional charge order.

A. M. Mulders; M. Bartkowiak; J. R. Hester; E. Pomjakushina; K. Conder

2011-10-03T23:59:59.000Z

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

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

SciTech Connect

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.

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

2010-10-21T23:59:59.000Z

82

Particle resuspension by an impacting vortex ring  

Science Journals Connector (OSTI)

Coherent vortex structures play a significant and important role in the dynamics of many commonly occurring natural flows, for example turbulent boundary layers and channel flows. One particularly important fe...

Rick J. Munro; Stuart B. Dalziel

2003-01-01T23:59:59.000Z

83

‘Optimal’ vortex rings and aquatic propulsion mechanisms  

Science Journals Connector (OSTI)

...vortex rings and aquatic propulsion mechanisms P. F. Linden...fluid mechanics behind these propulsion mechanisms and show that...over the cycle. 4. FISH PROPULSION BY UNDULATORY SWIMMING Most marine organisms have only discrete...

2004-01-01T23:59:59.000Z

84

Polarization dependent forces in optical vortex pipeline  

Science Journals Connector (OSTI)

We study both, theoretically and in experiments, the dependence of optical forces acting on a spherical particle guided in air with an optical vortex beam, on the light polarization...

Eckerskorn, Niko; Krolikowski, Wieslaw; Shvedov, Vladlen; Rode, Andrei

85

Airfoil Vortex Induced Vibration suppression devices  

E-Print Network (OSTI)

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 ...

Lee, Evan J. (Evan Joseph)

2007-01-01T23:59:59.000Z

86

Holographic Vortex Liquids and Superfluid Turbulence  

Science Journals Connector (OSTI)

...of Kelvin waves flowing along vortex strings in 3D quantum turbulence...theory correlators from non-critical string theory . Phys. Lett. B...S. , Emergence of turbulence in an oscillating Bose-Einstein condensate . Phys. Rev...

Paul M. Chesler; Hong Liu; Allan Adams

2013-07-26T23:59:59.000Z

87

E-Print Network 3.0 - antiferromagnetic domain fluctuations Sample...  

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in a diluted fcc antiferromagnet Carsten Wengel... on a Monte Carlo study of a diluted Ising antiferromagnet on a fcc lattice. This is a typical model example... of a highly...

88

E-Print Network 3.0 - antiferromagnetism Sample Search Results  

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in a diluted fcc antiferromagnet Carsten Wengel... on a Monte Carlo study of a diluted Ising antiferromagnet on a fcc lattice. This is a typical model example... of a highly...

89

E-Print Network 3.0 - antiferromagnetic materials Sample Search...  

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in a diluted fcc antiferromagnet Carsten Wengel... on a Monte Carlo study of a diluted Ising antiferromagnet on a fcc lattice. This is a typical model example... of a highly...

90

E-Print Network 3.0 - antiferromagnet-based nuclear spin Sample...  

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antiferromagnet-based nuclear spin Search Powered by Explorit Topic List Advanced Search Sample search results for: antiferromagnet-based nuclear spin Page: << < 1 2 3 4 5 > >> 1...

91

Effective theory of Fermi pockets in fluctuating antiferromagnets  

Science Journals Connector (OSTI)

We describe fluctuating two-dimensional metallic antiferromagnets by transforming to a rotating reference frame in which the electron spin polarization is measured by its projections along the local antiferromagnetic order. This leads to a gauge-theoretic description of an “algebraic charge liquid” involving spinless fermions and a spin S=1/2 complex scalar. We propose a phenomenological effective lattice Hamiltonian which describes the binding of these particles into gauge-neutral, electronlike excitations, and describe its implications for the electron spectral function across the entire Brillouin zone. We discuss connections of our results to photoemission experiments in the pseudogap regime of the cuprate superconductors.

Yang Qi and Subir Sachdev

2010-03-19T23:59:59.000Z

92

Reconnection of vortex filaments and Kolmogorov spectrum  

E-Print Network (OSTI)

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.

Sergey K. Nemirovskii

2014-04-19T23:59:59.000Z

93

Tunable negligible-loss energy transfer between dipolar-coupled magnetic disks by stimulated vortex gyration  

E-Print Network (OSTI)

structure of magnetic vortex cores. Science 298, 577– Park,Magnetic vortex core observation in circular dots of Permalloy. Science

Jung, Hyunsung

2014-01-01T23:59:59.000Z

94

Low-temperature vortex dynamics in a high-temperature superconductor  

Science Journals Connector (OSTI)

Magnetic-field gradients in the mixed state of a type-II superconductor are studied using Tl205 nuclear magnetic resonance (NMR) on Tl2Ba2Ca2Cu3O10+?. An anomalous peak was observed in the temperature dependence of the transverse relaxation rate at T/Tc?0.25. We attribute this behavior to magnetic-field flucutations from vortex dynamics. We interpret this behavior as a crossover of the principal time scale for vortex dynamics with that of the NMR experiment, approximately 100 ?s. The temperature dependence of this time scale is discussed.

Y.-Q. Song; S. Tripp; W. P. Halperin; L. Tonge; T. J. Marks

1994-12-01T23:59:59.000Z

95

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

SciTech Connect

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.

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

96

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

SciTech Connect

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.

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

2010-10-13T23:59:59.000Z

97

Sediment resuspension and erosion by vortex rings  

Science Journals Connector (OSTI)

Particle resuspension and erosion induced by a vortex ringinteracting with a sediment layer was investigated experimentally using flow visualization (particle image velocimetry) high-speed video and a recently developed light attenuation method for measuring displacements in bed level. Near-spherical sediment particles were used throughout with relative densities of 1.2–7 and diameters ( d ) ranging between 90 and 1600 ? ? m . Attention was focused on initially smooth horizontal bedforms with the vortex ring aligned to approach the bed vertically. Interaction characteristics were investigated in terms of the dimensionless Shields parameter defined using the vortex-ring propagation speed. The critical conditions for resuspension (whereby particles are only just resuspended) were determined as a function of particle Reynolds number (based on the particle settling velocity and d ). The effects of viscous damping were found to be significant for d / ? resuspension volumes are analyzed as a function interaction time impact condition and sediment size.

R. J. Munro; N. Bethke; S. B. Dalziel

2009-01-01T23:59:59.000Z

98

Vortex reconnections between coreless vortices in binary condensates  

SciTech Connect

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.

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

99

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

E-Print Network (OSTI)

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

Zuccher, Simone

100

Polarized Neutron Studies on Antiferromagnetic Single Crystals: Technical Report No. 4  

DOE R&D Accomplishments (OSTI)

The theory of neutron scattering by magnetic crystals as given by Halpern and Johnson predicts changes in the polarization state of the neutron beam upon scattering which depend upon the relative orientation of the neutron polarization vector and the crystal magnetic axis. This was investigated experimentally with a polarized beam spectrometer using single crystals of Cr{sub 2}O{sub 3} and alpha - Fe{sub 2}O{sub 3} in which reside unique antiferromagnetic axes. Studies were made on several different reflections in both crystals for a number of different temperatures both below and above the Neel point. Results support the theoretical predictions and indicate directions for the moments in these crystals consistent with previous work. A more detailed study of the polarization changes in the (111) reflection in alpha - Fe{sub 2}O{sub 3} at room temperature on application of a magnetic field was carried out, The results indicate that the principal source of the parasitic ferromagnetism in hematite is essentially independent of the orientation of the antiferromagnetic domains within the crystal.

Nathans, R.; Riste, T.; Shirane, G.; Shull, C.G.

1958-11-26T23:59:59.000Z

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Order and Correlation in Finite Antiferromagnetic Ising Chains  

Science Journals Connector (OSTI)

Several quantities associated with order and correlation in finite antiferromagnetic Ising chains (free ends) in the presence of a uniform magnetic field have been computed. The results show that although for 1?iis unaffected by the external field the quantities ?S i S j ? and ?S i ? may change sign for sufficiently large magnetic fields and the latter quantities thereby provide a more intuitive measure of the effect of the field on the spin order.

H. Falk

1972-01-01T23:59:59.000Z

102

Pressure dependent diffraction and spectroscopy of a dimerized antiferromagnet  

SciTech Connect

We present pressure dependent neutron diffraction and inelastic neutron scattering measurements of the dimerized antiferromagnet Ba$_3$Mn$_2$O$_8$. The room temperature diffraction measurements reveal a linear decrease in lattice constant as a function of applied pressure. No structural transitions are observed. The low-temperature neutron spectroscopy measurements indicate a small change in magnetic scattering intensity in the vicinity of the spin gap for pressures up to $P=0.6$~kbar.

Stone, Matthew B [ORNL; Tulk, Christopher A [ORNL; dos Santos, Antonio M. [Oak Ridge National Laboratory (ORNL); Molaison, Jamie J [ORNL; Chang, S. [Ames Laboratory; Leo, J B [National Institute of Standards and Technology (NIST), Gaithersburg, MD; Samulon, Eric C [Stanford University; Shapiro, Max C [Stanford University; Fisher, Ian R [Stanford University

2011-01-01T23:59:59.000Z

103

Jammed vortex matter Hajime Yoshino1  

E-Print Network (OSTI)

. 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

Katsumoto, Shingo

104

Vortex lines in films: Fields and interactions  

Science Journals Connector (OSTI)

General expressions are given for the magnetic field and energy of arbitrary arrangements of straight and curved vortices in an anisotropic superconductor film of finite thickness within anisotropic London theory. As examples we consider the magnetic field and interaction of straight perpendicular vortex lines in films of finite thickness.

Gilson Carneiro and Ernst Helmut Brandt

2000-03-01T23:59:59.000Z

105

Vortex Jitter in Hover Swathi M. Mula  

E-Print Network (OSTI)

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

Tinney, Charles E.

106

The multiple vortex nature of tropical cyclogenesis  

E-Print Network (OSTI)

) __________________________ __________________________ John Nielsen-Gammon Craig Epifanio (Chair of Committee) (Member) __________________________ __________________________ Fuqing Zhang Hongxing Liu (Member) (Member) December 2004 Major Subject: Atmospheric Sciences... iii ABSTRACT The Multiple Vortex Nature of Tropical Cyclogenesis. (December 2004) Jason Allen Sippel, B.S., Texas A&M University Chair of Advisory Committee: Dr. John Nielsen-Gammon This thesis contains an observational analysis...

Sippel, Jason Allen

2005-02-17T23:59:59.000Z

107

Quenching Processes in Flame-Vortex Interactions  

E-Print Network (OSTI)

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

Zingale, Michael

108

Vortex dynamics in 4 Banavara N. Shashikanth  

E-Print Network (OSTI)

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

Shashikanth, Banavara N.

109

Neutron Scattering Studies of Vortex Matter in Type-II Superconductors  

SciTech Connect

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.

Xinsheng Ling

2012-02-02T23:59:59.000Z

110

Orbital Degeneracy Removed by Charge Order in Triangular Antiferromagnet AgNiO{sub 2}  

SciTech Connect

We report a high-resolution neutron diffraction study on the orbitally degenerate spin-1/2 hexagonal metallic antiferromagnet AgNiO{sub 2}. A structural transition to a tripled unit cell with expanded and contracted NiO{sub 6} octahedra indicates {radical}(3)x{radical}(3) charge order on the Ni triangular lattice. This suggests charge order as a possible mechanism of lifting the orbital degeneracy in the presence of charge fluctuations, as an alternative to the more usual Jahn-Teller distortions. A novel magnetic ground state is observed at low temperatures with the electron-rich S=1 Ni sites arranged in alternating ferromagnetic rows on a triangular lattice, surrounded by a honeycomb network of nonmagnetic and metallic Ni ions. We also report first-principles band-structure calculations that explain microscopically the origin of these phenomena.

Wawrzynska, E.; Coldea, R. [H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Wheeler, E. M. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Institute Laue-Langevin, B.P. 156, 38042 Grenoble Cedex 9 (France); Mazin, I. I.; Johannes, M. D. [Code 6393, Naval Research Laboratory, Washington, D.C. 20375 (United States); Soergel, T.; Jansen, M. [Max-Planck Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Ibberson, R. M.; Radaelli, P. G. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom)

2007-10-12T23:59:59.000Z

111

E-Print Network 3.0 - antiferromagnetic black sodalite Sample...  

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Nowak, K. D. Usadel... -mail: michael@thp.uni-duisburg.de May 12, 1997 Abstract Diluted Ising antiferromagnets in a homogenous magnetic... magnetization of diluted Ising...

112

E-Print Network 3.0 - anti-ferromagnetic heisenberg chains Sample...  

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of ferromag- netic, anti-ferromagnetic and competing... temperature of one-dimensional Ising models with ferromagnetic, anti- ferromagnetic and ... Source: Stariolo, Daniel...

113

E-Print Network 3.0 - antiferromagnetic chain mncl Sample Search...  

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transitions of quantum systems, and their connection to thermal phase transitions. 4. Ising chain... in a transverse field and spin dimer antiferromagnets: weak and strong...

114

E-Print Network 3.0 - antiferromagnetic interlayer coupling Sample...  

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28 TWO-DIMENSIONAL BEHAVIOR OF THE SUBLATTICE MAGNETIZATION IN THREE DIMENSIONAL ISING Summary: intra-layer coupling to z neighbors, zJ > 0, and an antiferromagnetic...

115

A Vortex Contactor for Carbon Dioxide Separations  

NLE Websites -- All DOE Office Websites (Extended Search)

Vortex Contactor for Carbon Dioxide Separations Vortex Contactor for Carbon Dioxide Separations Kevin T. Raterman (ratekt@inel.gov; 208-526-5444) Michael McKellar (mgq@inel.gov; 208-526-1346) Anna Podgorney (poloak@inel.gov; 208-526-0064) Douglas Stacey (stacde@inel.gov; 208-526-3938) Terry Turner (tdt@inel.gov; 208-526-8623) Idaho National Engineering and Environmental Laboratory P.O. Box 1625 Idaho Falls, Idaho 83415-2110 Brian Stokes (bxs9@pge.com; 415-972-5591) John Vranicar (jjv2@pge.com; 415-972-5591) Pacific Gas & Electric Company 123 Mission Street San Francisco, CA 94105 Introduction Many analysts 1,2,3 identify carbon dioxide (CO 2 ) capture and separation as a major roadblock in efforts to cost effectively mitigate greenhouse gas emissions via sequestration. An assessment 4 conducted by the International Energy Agency (IEA)

116

Vortex Dynamics in NanoScale Materials  

NLE Websites -- All DOE Office Websites (Extended Search)

Into the Vortex: Dynamics in Nanoscale Materials Into the Vortex: Dynamics in Nanoscale Materials Micron and nanosized magnets are of great interest for their potential applications in new electronic devices, such as magnetic random access memories. As the size of magnets is reduced to a 1-micron scale and below, the boundaries (surfaces, perimeters, etc) of the objects begin to profoundly influence both the static and dynamic behavior of the materials. Researchers from Argonne's Materials Science Division (MSD), Center for Nanoscale Materials (CNM), and Advanced Photon Source (APS) have recently examined the dynamics of 3- to 7-micron-diameter NiFe alloy disks with a combination of theoretical calculations and a new time-resolved magnetic imaging technique using synchrotron-based x-ray photoemission electron

117

Acceleration and vortex filaments in turbulence  

E-Print Network (OSTI)

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.

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

2005-01-23T23:59:59.000Z

118

Jet?vortex Interaction: A Numerical Study  

Science Journals Connector (OSTI)

The interaction of a vortex and a jet plays an important role for many industrial processes such as Carbon Black formation or combustion in diesel engines. The knowledge of physics of these phenomena is crucial for engineers but also for scientists who wish to reveal many interesting and complex issues hidden there. In this research we numerically investigate cases where a cylindrical reactor is charged with gas injected through five ports. The first one is located along the main axis of the cylinder and this leads to the formation of the main jet. The other four ports are situated along the side walls such that the gas entering the cylinder tangentially through them causes a vortex to be formed. The objective of this paper is to show the fundamental physical phenomena and also how the initial and boundary conditions influence the results. Our most important observation at this stage is that the mixing process is more intense if the vortex is inclined towards x?axis. The results are mainly shown as snapshots of gas velocity.

Catalin G. Ilea; Pawel Kosinski; Alex C. Hoffmann

2009-01-01T23:59:59.000Z

119

Liquid Vortex Shielding for Fusion Energy Applications  

SciTech Connect

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.

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

120

Three-Dimensional Nonlinear Lattices: From Oblique Vortices and Octupoles to Discrete Diamonds and Vortex Cubes  

Science Journals Connector (OSTI)

We construct a variety of novel localized topological structures in the 3D discrete nonlinear Schrödinger equation. The states can be created in Bose-Einstein condensates trapped in strong optical lattices and crystals built of microresonators. These new structures, most of which have no counterparts in lower dimensions, range from multipole patterns and diagonal vortices to vortex “cubes” (stack of two quasiplanar vortices) and “diamonds” (formed by two orthogonal vortices).

R. Carretero-González; P. G. Kevrekidis; B. A. Malomed; D. J. Frantzeskakis

2005-05-23T23:59:59.000Z

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Magnetic Vortex Core Reversal by Low-Field Excitations  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known...

122

Novel Vortex Generator and Mode Converter for Electron Beams  

Science Journals Connector (OSTI)

A mode converter for electron vortex beams is described. Numerical simulations, confirmed by experiment, show that the converter transforms a vortex beam with a topological charge m=±1 into beams closely resembling Hermite-Gaussian HG10 and HG01 modes. The converter can be used as a mode discriminator or filter for electron vortex beams. Combining the converter with a phase plate turns a plane wave into modes with topological charge m=±1. This combination serves as a generator of electron vortex beams of high brilliance.

P. Schattschneider; M. Stöger-Pollach; J. Verbeeck

2012-08-22T23:59:59.000Z

123

Energy Separation And Lox Separation Studies In Vortex Tubes.  

E-Print Network (OSTI)

??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)

Behera, Upendra

2011-01-01T23:59:59.000Z

124

Magnetic-Field Induced Quantum Phase Transitions in Triangular-Lattice Antiferromagnets  

E-Print Network (OSTI)

Magnetic-Field Induced Quantum Phase Transitions in Triangular-Lattice Antiferromagnets T Ono1, H Department of Physics, Smith College, Northampton, Massachusetts 01063, USA 5 National High Magnetic Field are magnetically described as quasi-two-dimensional triangular-lattice antiferromagnets with spin-1 2 and 1

McQuade, D. Tyler

125

Antiferromagnetic exchange bias of a ferromagnetic semiconductor by a ferromagnetic metal  

SciTech Connect

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.

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

126

Memory effect and temperature behavior in spin valves with and without antiferromagnetic subsystems  

E-Print Network (OSTI)

Memory effect and temperature behavior in spin valves with and without antiferromagnetic subsystems Temperature behavior and memory effect in standard spin valves SV and SVs with synthetic antiferromagnetic Co/Ru/Co SV-SAF subsystems have been studied. SV-SAFs show much better temperature stability. Memory effect

Xiao, John Q.

127

Vortex motion rectification in Josephson junction arrays with a ratchet potential  

E-Print Network (OSTI)

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.

D. E. Shalom; H. Pastoriza

2004-11-19T23:59:59.000Z

128

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

E-Print Network (OSTI)

'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... TABLE I II BOUNDARY LAYER PROFILE DATA IN THE VICINITY OF A VORTEX FILAMENT AT STATION 0 7 Tube Number I 2 3 4. 5 6 7 8 9 '10 I 2 3 4 5 6 7 8 9 10 I 2 3 4 5 6 7 8 9 10 Ft-Fs in. H 0 1. 31 1. 31 1. 31 I . 26 1. 20...

Mount, Glynn O., Jr

2012-06-07T23:59:59.000Z

129

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

NLE Websites -- All DOE Office Websites (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...

130

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

NLE Websites -- All DOE Office Websites (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:...

131

Transverse energy circulation and the edge diffraction of an optical vortex beam  

Science Journals Connector (OSTI)

Edge diffraction of a circular Laguerre–Gaussian beam represents an example of the optical vortex symmetry breakdown in which the hidden “vortex” energy...

Bekshaev, Aleksandr Ya; Mohammed, Kadhim A; Kurka, Ivan A

2014-01-01T23:59:59.000Z

132

Z2 index for gapless fermionic modes in the vortex core of three-dimensional paired Dirac fermions  

Science Journals Connector (OSTI)

We consider the gapless modes along the vortex line of the fully gapped, momentum independent paired states of three-dimensional Dirac fermions. For this, we require the solution of fermion zero modes of the corresponding two-dimensional problem in the presence of a point vortex, in the plane perpendicular to the vortex line. Based on the spectral symmetry requirement for the existence of the zero mode, we identify the appropriate generalized Jackiw-Rossi Hamiltonians for different paired states. A four-dimensional generalized Jackiw-Rossi Hamiltonian possesses spectral symmetry with respect to an antiunitary operator, and gives rise to a single zero mode only for the odd vorticity, which is formally described by a Z2 index. In the presence of generic perturbations such as chemical potential, Dirac mass, and Zeeman couplings, the associated two-dimensional problem for the odd parity topological superconducting state maps onto two copies of generalized Jackiw-Rossi Hamiltonian, and consequently an odd vortex binds two Majorana fermions. In contrast, there are no zero-energy states for the topologically trivial s-wave superconductor in the presence of any chiral symmetry breaking perturbation in the particle-hole channel, such as regular Dirac mass. We show that the number of one-dimensional dispersive modes along the vortex line is also determined by the index of the associated two-dimensional problem. For an axial superfluid state in the presence of various perturbations, we discuss the consequences of the Z2 index on the anomaly equations.

Bitan Roy and Pallab Goswami

2014-04-14T23:59:59.000Z

133

Magnetic Vortex Core Reversal by Low-Field Excitations  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Vortex Core Reversal by Magnetic Vortex Core Reversal by Low-Field Excitations Magnetic Vortex Core Reversal by Low-Field Excitations Print Wednesday, 28 March 2007 00:00 In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very strong magnetic fields of around half a tesla (approximately one-third the field of the strongest permanent magnet) were previously thought to be necessary to accomplish this. At the ALS, a team of researchers from Germany, Belgium, and the U.S. has used time-resolved scanning transmission x-ray microscopy (STXM) to observe vortex motion and demonstrate the feasibility of using weak magnetic fields as low as 1.5 millitesla (mT) to reverse the direction of a vortex core. The observed switching mechanism, which can be understood within the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application to data storage technologies.

134

Finned Tube With Vortex Generators For A Heat Exchanger.  

DOE Patents (OSTI)

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 least 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.

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

2004-09-14T23:59:59.000Z

135

Spin-waves in Antiferromagnetically-Coupled Bimetallic Oxalates  

SciTech Connect

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.

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

2009-01-01T23:59:59.000Z

136

Dynamics of Magnetized Vortex Tubes in the Solar Chromosphere  

E-Print Network (OSTI)

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...

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

2012-01-01T23:59:59.000Z

137

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

SciTech Connect

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.

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

138

Electromagnetic Behavior of the Vortex Sponge  

Science Journals Connector (OSTI)

In an introductory paper the vortex sponge was shown to be governed in restricted cases by Maxwell's free-space equations. In the present paper analogs to electric and magnetic energies and Poynting's theorem are derived by simple mechanical considerations. Rotational stability suggested originally by MacCullagh as a fundamental property of a luminiferous ether turns out to be a quality of the medium as do the stresses introduced by Faraday and Maxwell to explain the mechanical actions of electric and magnetic fields. A rudimentary model for the electrostatic field is suggested on this basis. A conventional definition of charge and the laws of Coulomb and Biot complete Maxwell's equations for cases including charges and currents. A model of the magnetic field based on the bulk rotation and the Faraday-Maxwell stresses combined with the laws of Coulomb and Biot permits the inference of the Lorentz force. Although numerous gaps occur in the treatment it seems not unlikely that the vortex sponge has the qualities described by the electromagnetic field equations as well as the mechanical attributes required for a model of these fields.

Edward M. Kelly

1964-01-01T23:59:59.000Z

139

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

E-Print Network (OSTI)

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

Miguel-Lopez, Carmen

140

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

E-Print Network (OSTI)

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

Anlage, Steven

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

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

E-Print Network (OSTI)

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

Wysin, Gary

142

Magnetic Vortex Core Reversal by Low-Field Excitations  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Vortex Core Reversal by Low-Field Excitations Print Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very strong magnetic fields of around half a tesla (approximately one-third the field of the strongest permanent magnet) were previously thought to be necessary to accomplish this. At the ALS, a team of researchers from Germany, Belgium, and the U.S. has used time-resolved scanning transmission x-ray microscopy (STXM) to observe vortex motion and demonstrate the feasibility of using weak magnetic fields as low as 1.5 millitesla (mT) to reverse the direction of a vortex core. The observed switching mechanism, which can be understood within the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application to data storage technologies.

143

Magnetic Vortex Core Reversal by Low-Field Excitations  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Vortex Core Reversal by Low-Field Excitations Print Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very strong magnetic fields of around half a tesla (approximately one-third the field of the strongest permanent magnet) were previously thought to be necessary to accomplish this. At the ALS, a team of researchers from Germany, Belgium, and the U.S. has used time-resolved scanning transmission x-ray microscopy (STXM) to observe vortex motion and demonstrate the feasibility of using weak magnetic fields as low as 1.5 millitesla (mT) to reverse the direction of a vortex core. The observed switching mechanism, which can be understood within the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application to data storage technologies.

144

Magnetic Vortex Core Reversal by Low-Field Excitations  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Vortex Core Reversal by Low-Field Excitations Print Magnetic Vortex Core Reversal by Low-Field Excitations Print In micrometer-sized magnetic thin films, the magnetization typically adopts an in-plane, circular configuration known as a magnetic vortex. At the vortex core, the magnetization turns sharply out of the plane, pointing either up or down. Magnetic data storage based on this binary phenomenon is an intriguing concept, but it would require the ability to flip the vortex cores on demand. Because these structures are highly stable, very strong magnetic fields of around half a tesla (approximately one-third the field of the strongest permanent magnet) were previously thought to be necessary to accomplish this. At the ALS, a team of researchers from Germany, Belgium, and the U.S. has used time-resolved scanning transmission x-ray microscopy (STXM) to observe vortex motion and demonstrate the feasibility of using weak magnetic fields as low as 1.5 millitesla (mT) to reverse the direction of a vortex core. The observed switching mechanism, which can be understood within the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application to data storage technologies.

145

MHK Technologies/Vortex Induced Vibrations Aquatic Clean Energy VIVACE |  

Open Energy Info (EERE)

Vortex Induced Vibrations Aquatic Clean Energy VIVACE Vortex Induced Vibrations Aquatic Clean Energy VIVACE < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Vortex Induced Vibrations Aquatic Clean Energy VIVACE.jpg Technology Profile Primary Organization Vortex Hydro Energy LLC Project(s) where this technology is utilized *MHK Projects/Marine Hydrodynamics Laboratory at the University of Michigan Technology Resource Click here Current/Tidal Technology Type Click here Reciprocating Device Technology Readiness Level Click here TRL 4: Proof of Concept Technology Description The VIVACE (Vortex Induced Vibrations Aquatic Clean Energy) device is based on the extensively studied phenomenon of Vortex Induced Vibrations (VIV), which was first observed five-hundred years ago by Leonardo DaVinci in the form of 'Aeolian Tones.' VIV results from vortices forming and shedding on the downstream side of a bluff body in a current. Vortex shedding alternates from one side to the other, thereby creating a vibration or oscillation. The VIV phenomenon is non-linear, which means it can produce useful energy at high efficiency over a wide range of current speeds and directions.This converter is unlike any existing technology, as it does not use turbines, propellers, or dams. VIVACE converts the horizontal hydrokinetic energy of currents into cylinder mechanical energy. The latter is then converted to electricity through electric power generators.

146

E-Print Network 3.0 - antiferromagnetic phase transition Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

C8, Suppl6ment au no 12,Tome 49, d6cembre 1988 Summary: . The transition to the Ising-like antiferromagnetic phase is possible where the magnetic field-dependent out......

147

E-Print Network 3.0 - antiferromagnetic ising model Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

ising model Search Powered by Explorit Topic List Advanced Search Sample search results for: antiferromagnetic ising model Page: << < 1 2 3 4 5 > >> 1 J. Phys. I France 3 (1993)...

148

Vortex configurations of bosons in an optical lattice  

SciTech Connect

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.

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

149

Pinned magnetization in the antiferromagnet and ferromagnet of an exchange bias system  

SciTech Connect

Using polarized neutron reflectometry, we obtained separate depth profiles for pinned and unpinned magnetization across the interface of a ferromagnet/antiferromagnet bilayer as a function of the sign of exchange bias. The pinned and unpinned magnetization depth profiles are nonuniform and extend well beyond the chemical interface, suggesting an interfacial region magnetically distinct from its surroundings. A model that includes pinned and unpinned moments in the ferromagnet and antiferromagnet is developed for a complete description of the data.

Fitzsimmons, M. R.; Kirby, B. J. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Roy, S.; Li Zhipan; Roshchin, Igor V.; Schuller, Ivan K. [Department of Physics, University of California at San Diego, La Jolla, California 92093 (United States); Sinha, S. K. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Department of Physics, University of California at San Diego, La Jolla, California 92093 (United States)

2007-06-01T23:59:59.000Z

150

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

E-Print Network (OSTI)

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.

M. Cristina Marchetti; Leo Radzihovsky

1999-07-01T23:59:59.000Z

151

State  

U.S. Energy Information Administration (EIA) Indexed Site

Biodiesel Producers and Production Capacity by State, September 2013 Biodiesel Producers and Production Capacity by State, September 2013 State Number of Producers Annual Production Capacity (million gallons per year) Alabama 3 47 Alaska - - Arizona 1 2 Arkansas 3 85 California

152

Monopole-Antimonopole Chains and Vortex Rings  

E-Print Network (OSTI)

We consider static axially symmetric solutions of SU(2) Yang-Mills-Higgs theory. The simplest such solutions represent monopoles, multimonopoles and monopole-antimonopole pairs. In general such solutions are characterized by two integers, the winding number m of their polar angle, and the winding number n of their azimuthal angle. For solutions with n=1 and n=2, the Higgs field vanishes at m isolated points along the symmetry axis, which are associated with the locations of m monopoles and antimonopoles of charge n. These solutions represent chains of m monopoles and antimonopoles in static equilibrium. For larger values of n, totally different configurations arise, where the Higgs field vanishes on one or more rings, centered around the symmetry axis. We discuss the properties of such monopole-antimonopole chains and vortex rings, in particular their energies and magnetic dipole moments, and we study the influence of a finite Higgs self-coupling constant on these solutions.

Burkhard Kleihaus; Jutta Kunz; Yasha Shnir

2004-05-19T23:59:59.000Z

153

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

E-Print Network (OSTI)

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.

Youhei Yamaji; Masatoshi Imada

2014-03-12T23:59:59.000Z

154

Argonne CNM Highlight: Biofunctionalized magnetic-vortex microdiscs for  

NLE Websites -- All DOE Office Websites (Extended Search)

Biofunctionalized magnetic-vortex microdiscs for targeted cancer-cell destruction Biofunctionalized magnetic-vortex microdiscs for targeted cancer-cell destruction Magnetic microdisks Reflection optical microscope image of a dried suspension of the discs prepared via magnetron sputtering and optical lithography. Magnetic spin vortex Model of magnetic-vortex spin distribution in a disc. Users from Argonne's Materials Science Division and University of Chicago's Pritzker School of Medicine, working collaboratively on a user science project with CNM's Nanobio Interfaces Group, have discovered that nanostructured magnetic materials offer exciting avenues for probing cell mechanics, activating mechanosensitive ion channels, and advancing potential cancer therapies. Their new report describes an approach based on interfacing cells with lithographically defined microdiscs (1-micron

155

A study on passive methods of vortex induced vibrations suppression  

E-Print Network (OSTI)

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 ...

Galvao, Richardo A

2008-01-01T23:59:59.000Z

156

Experimental demonstration of vortex pancake in high temperature superconductor  

Science Journals Connector (OSTI)

In order to demonstrate the existence of the vortex pancake in high temperature superconductor experimentally, a configuration in which the current...E-j relation obtained with this electrodes spatial configurati...

Wei-xian Wang; Yu-heng Zhang

2006-09-01T23:59:59.000Z

157

MHK Technologies/SeaUrchin Vortex Reaction Turbine | Open Energy  

Open Energy Info (EERE)

SeaUrchin Vortex Reaction Turbine SeaUrchin Vortex Reaction Turbine < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage SeaUrchin Vortex Reaction Turbine.jpg Technology Profile Primary Organization Elemental Energy Technologies Limited ABN 46 128 491 903 Technology Resource Click here Current Technology Type Click here Axial Flow Turbine Technology Readiness Level Click here TRL 4 Proof of Concept Technology Description A revolutionary vortex reaction turbine branded the SeaUrchin an advanced third generation marine turbine technology capable of delivering inexpensive small to large scale baseload or predictable electricity by harnessing the kinetic energy of free flowing ocean currents tides and rivers Technology Dimensions Device Testing Date Submitted 55:15.2

158

Self-Consistent Electronic Structure of a dx2-y2 and a dx2-y2 + idxy Vortex  

Science Journals Connector (OSTI)

We investigate quasiparticle states associated with an isolated vortex in a d-wave superconductor using a self-consistent Bogoliubov–de Gennes formalism. For a pure dx2-y2 superconductor we find that there exist no bound states in the core; all the states are extended with continuous energy spectrum. This result is inconsistent with the existing experimental data on cuprates. We propose an explanation for this data in terms of a magnetic-field-induced dx2-y2+idxy state recently invoked in connection with the thermal conductivity measurements on Bi2Sr2CaCu2O8.

M. Franz and Z. Tešanovi?

1998-05-25T23:59:59.000Z

159

Spin and charge dynamics of the ferromagnetic and antiferromagnetic two-dimensional half-filled Kondo lattice model  

Science Journals Connector (OSTI)

We present a detailed numerical study of ground state and finite temperature spin and charge dynamics of the two-dimensional Kondo lattice model with hopping t and exchange J. Our numerical results stem from auxiliary field quantum Monte Carlo simulations formulated in such a way that the sign problem is absent at half-band filling thus allowing us to reach lattice sizes up to 12×12. At T=0 and antiferromagnetic couplings J>0 the competition between the Ruderman-Kittel-Kasuya-Yosida interaction and the Kondo effect triggers a quantum phase transition between antiferromagnetically ordered and magnetically disordered insulators: Jc/t=1.45±0.05. At J0, the single-particle spectral function A(k?,?) shows a dispersion relation following that of hybridized bands as obtained in the noninteracting periodic Anderson model. In the ordered phase this feature is supplemented by shadows, thus allowing an interpretation in terms of the coexistence of Kondo screening and magnetic ordering. In contrast, at J<0 the single-particle dispersion relation follows that of noninteracting electrons in a staggered external magnetic field. At finite temperatures spin TS and charge TC scales are defined by locating the maximum in the charge and spin uniform susceptibilities. For weak to intermediate couplings, TS marks the onset of antiferromagnetic fluctuations—as observed by a growth of the staggered spin susceptibility—and follows a J2 law. At strong couplings TS scales as J. On the other hand TC scales as J both in the weak- and strong-coupling regime. At and slightly below TC we observe (i) the onset of screening of the magnetic impurities, (ii) a rise in the resistivity as a function of decreasing temperature, (iii) a dip in the integrated density of states at the Fermi energy, and finally (iv) the occurrence of hybridized bands in A(k?,?). It is shown that in the weak-coupling limit, the charge gap of order J is formed only at TS and is hence of magnetic origin. The specific heat shows a two-peak structure. The low-temperature peak follows TS and is hence of magnetic origin. Our results are compared to various mean-field theories.

S. Capponi and F. F. Assaad

2001-03-30T23:59:59.000Z

160

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

SciTech Connect

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.

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

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Ultra-Low NOx Advanced Vortex Combustor  

SciTech Connect

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.

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

162

ULTRA-LOW NOX ADVANCED VORTEX COMBUSTOR  

SciTech Connect

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.

Ryan G. Edmonds; Robert C. Steele; Joseph T. Williams; Douglas L. Straub; Kent H. Casleton; Avtar Bining

2006-05-01T23:59:59.000Z

163

Persistence of magnons in a site-diluted dimerized frustrated antiferromagnet  

NLE Websites -- All DOE Office Websites (Extended Search)

Persistence of magnons in a site-diluted dimerized frustrated antiferromagnet Persistence of magnons in a site-diluted dimerized frustrated antiferromagnet This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2011 J. Phys.: Condens. Matter 23 416003 (http://iopscience.iop.org/0953-8984/23/41/416003) Download details: IP Address: 128.219.49.9 The article was downloaded on 17/10/2011 at 17:07 Please note that terms and conditions apply. View the table of contents for this issue, or go to the journal homepage for more Home Search Collections Journals About Contact us My IOPscience IOP PUBLISHING JOURNAL OF PHYSICS: CONDENSED MATTER J. Phys.: Condens. Matter 23 (2011) 416003 (9pp) doi:10.1088/0953-8984/23/41/416003 Persistence of magnons in a site-diluted dimerized frustrated antiferromagnet M B Stone 1 , A Podlesnyak 1 , G Ehlers

164

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

E-Print Network (OSTI)

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).

A. A. Kokin

2004-10-31T23:59:59.000Z

165

Wave–vortex interactions in the nonlinear Schrödinger equation  

SciTech Connect

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.

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

166

UBIQUITOUS SOLAR ERUPTIONS DRIVEN BY MAGNETIZED VORTEX TUBES  

SciTech Connect

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.

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

167

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

E-Print Network (OSTI)

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...

Yang, Yi

2012-02-14T23:59:59.000Z

168

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (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...

169

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

170

From antiferromagnetism to d-wave superconductivity in the two-dimensional t-J model  

Science Journals Connector (OSTI)

We have found that the two dimensional t-J model, for the physical parameter range J/t=0.4 reproduces the main experimental qualitative features of high-Tc copper oxide superconductors: d-wave superconducting correlations are strongly enhanced upon small doping and clear evidence of off-diagonal long-range order is found at the optimal doping ??0.15. On the other hand, antiferromagnetic long-range order, clearly present at zero hole doping, is suppressed at small hole density with clear absence of antiferromagnetism at ?>?0.1.

Matteo Calandra and Sandro Sorella

2000-05-01T23:59:59.000Z

171

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

E-Print Network (OSTI)

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.

Akihiko Sekine; Kentaro Nomura

2014-01-18T23:59:59.000Z

172

Mutual Chern-Simons gauge theory of spontaneous vortex phase  

Science Journals Connector (OSTI)

We apply the mutual Chern-Simons effective theory [Kou, Qi, and Weng, Phys. Rev. B 71, 235102 (2005)] of the doped Mott insulator to the study of the so-called spontaneous vortex phase in the low-temperature pseudogap region, which is characterized by strong unconventional superconducting fluctuations. An effective description for the spontaneous vortex phase is derived from the general mutual Chern-Simons Lagrangian, based on which the physical properties including the diamagnetism, spin paramagnetism, magnetoresistance, and the Nernst coefficient, have been quantitatively calculated. The phase boundaries of the spontaneous vortex phase, which sits between the onset temperature Tv and the superconducting transition temperature Tc, are also determined within the same framework. The results are consistent with the experimental measurements of the cuprates.

Xiao-Liang Qi and Zheng-Yu Weng

2007-09-07T23:59:59.000Z

173

Ubiquitous Solar Eruptions Driven by Magnetized Vortex Tubes  

E-Print Network (OSTI)

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.

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

2013-01-01T23:59:59.000Z

174

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

E-Print Network (OSTI)

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

Fontelos, Marco

175

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

E-Print Network (OSTI)

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

Wright, J. Douglas

176

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

E-Print Network (OSTI)

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

Barr, Al

177

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

E-Print Network (OSTI)

, 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

Zuccher, Simone

178

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

E-Print Network (OSTI)

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

Henley, Christopher L.

179

Vortex Formation in a Plasma Interacting with Neutral Flow  

SciTech Connect

Recently, it has been observed that there exists a class of vortices which rotates in the opposite direction to ExB drift (referred to as anti-ExB vortex). This result suggests that a predominant force other than electric field is acting on ions. It is found that momentum transport and resultant force generation through the interaction between ions and neutral flow play an essential role on anti-ExB vortex formation. The existence of inward neutral flow, which drives the ions in the anti-ExB direction, has been confirmed using a newly-developed high-resolution laser induced fluorescence (LIF) spectroscopy system.

Tanaka, M. Y.; Ogiwara, K.; Etoh, S. [Department of High Energy Engineering Science, Kyushu University, Kasuga-koen 6-1, Kasuga 816-8580 (Japan); Aramaki, M. [Department of Electrical Engineering, Nagoya University, Chikusa, Nagoya 464-8603 (Japan); Yoshimura, S. [National Institute for Fusion Science, Oroshi 322-6, Toki 509-5292 (Japan); Varanjes, J. [Center for Plasma Astrophysics, Celestijnenlaan 200 B 3001 Leuven (Belgium)

2008-10-15T23:59:59.000Z

180

Laboratory Analysis of Vortex Dynamics For Shallow Tidal Inlets  

E-Print Network (OSTI)

LABORATORY ANALYSIS OF VORTEX DYNAMICS FOR SHALLOW TIDAL INLETS A Thesis by KERRI ANN WHILDEN Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements for the degree of MASTER OF SCIENCE August 2009... Major Subject: Ocean Engineering LABORATORY ANALYSIS OF VORTEX DYNAMICS FOR SHALLOW TIDAL INLETS A Thesis by KERRI ANN WHILDEN Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements for the degree...

Whilden, Kerri Ann

2010-10-12T23:59:59.000Z

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Revival of Classical Vortex Generators Now for Transition Delay  

Science Journals Connector (OSTI)

Classical vortex generators, known for their efficiency in delaying or even inhibiting boundary layer separation, are here shown to be coveted devices for transition to turbulence delay. The present devices are miniature with respect to classical vortex generators but are tremendously powerful in modulating the laminar boundary layer in the direction orthogonal to the base flow and parallel to the surface. The modulation generates an additional term in the perturbation energy equation, which counteracts the wall-normal production term and, hence, stabilizes the flow. Our experimental results show that these devices are really effective in delaying transition, but we also reveal their Achilles’ heel.

Shahab Shahinfar; Sohrab S. Sattarzadeh; Jens H. M. Fransson; Alessandro Talamelli

2012-08-16T23:59:59.000Z

182

Magnetic properties of rare-earth antiferromagnets studied using a two-ion model  

Science Journals Connector (OSTI)

In this paper, a two-ion model for rare-earth antiferromagnets is proposed and employed to describe the magnetic behavior of HoNi2B2C and DyFe2Si2 at low temperatures. The calculated temperature dependence of the susceptibilities and magnetizations along the hard and easy directions, respectively, shows very good agreement with experimental results.

Z.-S. Liu; M. Diviš; V. Sechovský

2008-12-05T23:59:59.000Z

183

Quasielastic Neutron Scattering in the High-Field Phase of a Haldane Antiferromagnet  

Science Journals Connector (OSTI)

Inelastic neutron scattering experiments on the Haldane-gap quantum antiferromagnet Ni(C5D14N2)2-N3(PF6) are performed in magnetic fields below and above the critical field Hc at which the gap closes. Quasielastic neutron scattering is found for H>Hc, indicating topological excitations in the high-field phase.

A. Zheludev; Z. Honda; Y. Chen; C. L. Broholm; K. Katsumata; S. M. Shapiro

2002-02-05T23:59:59.000Z

184

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

E-Print Network (OSTI)

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

Pickett, Warren

185

Uncompensated Moments in Antiferromagnets: Origin, Properties and Role in Exchange Bias  

E-Print Network (OSTI)

-3003, USA. 3 Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. 4 of uncompensated magnetization in antiferromagnets performed by SQUID and VSM magnetometry, and polarized neutron reflectometry. This uncompensated magnetization is observed and studied as a function of temperature and cooling

Roshchin, Igor V.

186

Order by disorder in the antiferromagnetic Ising model on an elastic triangular lattice  

Science Journals Connector (OSTI)

...Sondhi SL ( 2002 ) Order by distortion and string modes in pyrochlore antiferromagnets . Phys Rev Lett 88 : 067203 . 10...Ising model under a time-dependent oscillating field . Phys Rev A 41 : 4251 – 4254...two-dimensional kinetic Ising model in an oscillating field . Phys Rev E Stat Nonlin Soft Matter...

Yair Shokef; Anton Souslov; T. C. Lubensky

2011-01-01T23:59:59.000Z

187

Role of the core energy in the vortex Nernst effect  

Science Journals Connector (OSTI)

We present an analytical study of diamagnetism and transport in a film with superconducting phase fluctuations, formulated in terms of vortex dynamics within the Debye-Hückel approximation. We find that the diamagnetic and Nernst signals decay strongly with temperature in a manner that is dictated by the vortex core energy. Using the theory to interpret Nernst measurements of underdoped La2?xSrxCuO4 above the critical temperature regime, we obtain a considerably better fit to the data than a fit based on Gaussian order-parameter fluctuations. Our results indicate that the core energy in this system scales roughly with the critical temperature and is significantly smaller than expected from BCS theory. Furthermore, it is necessary to assume that the vortex mobility is much larger than the Bardeen-Stephen value in order to reconcile conductivity measurements with the same vortex picture. Therefore, either the Nernst signal is not due to fluctuating vortices, or vortices in underdoped La2?xSrxCuO4 have highly unconventional properties.

Gideon Wachtel and Dror Orgad

2014-11-11T23:59:59.000Z

188

New vortex ring configurations for the MAP dyon solutions  

Science Journals Connector (OSTI)

Electrically charged magnetic solutions of SU (2) Yang-Mills-Higgs theory with net zero topological charge has been obtained as axially symmetric saddle-point solutions in Ref. [1]. These solutions are characterized by an integer the winding number n of their azimuthal angle ? and an electric charge parameter 0vortex ring configuration with n=2 ?=0.65 and varying Higgs field strength. Our observations showed that beside the fundamental solution which is an electrically charged MAP solution there also exist two other branches of eclectically charged vortex ring solutions which both appear at ?=20.45. The difference in total energy between these two branches of solution is very small but the difference in diameter of vortex rings of the two branches is quite significant. Finding of a branching phenomena in presence of a fundamental MAP solution has been for the first time. In Ref. [2] new branching solutions occur for the electrically neutral case in presence of fundamental vortex ring solutions but not for the fundamental MAP solution.

2014-01-01T23:59:59.000Z

189

Creation and pinning of vortex-antivortex pairs  

E-Print Network (OSTI)

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...

Kim, Sangbum; Hu, Chia-Ren; Andrews, Malcolm J.

2006-01-01T23:59:59.000Z

190

Vortex trimer in three-component Bose-Einstein condensates  

E-Print Network (OSTI)

Vortex trimer is predicted in three-component Bose-Einstein condensates with internal coherent couplings. The molecule is made by three constituent vortices which are bounded by domain walls of the relative phases. We show that the shape and the size of the molecule can be controlled by changing the internal coherent couplings.

Minoru Eto; Muneto Nitta

2012-01-01T23:59:59.000Z

191

High-Resolution Simulations of Parallel BladeVortex Interactions  

E-Print Network (OSTI)

= 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

Alonso, Juan J.

192

WAVE-VORTEX INTERACTIONS IN THE ATMOSPHERE, AND CLIMATE  

E-Print Network (OSTI)

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

Vellekoop, Michel

193

Modified Black Hole with Polar Jet and Vortex  

E-Print Network (OSTI)

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.

T. Tmmalm

2001-12-06T23:59:59.000Z

194

Vortex strings in electric dipole radiation near a mirror  

Science Journals Connector (OSTI)

Abstract The energy flow pattern of the radiation emitted by an oscillating electric dipole near a mirror has a complicated structure, including numerous singularities and vortices. We consider the flow lines of energy in the plane through the surface normal and the oscillation direction of the dipole. It is shown that the vortices are due to the vanishing of the magnetic field at their centers. The locations of the vortices have the appearance of beads on strings, and there are four such strings. The rotation direction of the energy flow for each vortex on a given string is the same. There are two strings with clockwise rotation and two strings with counterclockwise rotation. Field lines of energy flow either start or end at the center of a vortex. For a given string, field lines end at each vortex or field lines start at each vortex. There are two strings on which field lines end at the centers of the vortices, and there are two strings on which field lines start inside the vortices.

Xin Li; Henk F. Arnoldus

2013-01-01T23:59:59.000Z

195

Density of hole states for the strongly correlated infinite-dimensional Hubbard model  

Science Journals Connector (OSTI)

The density of hole states for the strongly correlated infinite-dimensional Hubbard model is studied with use of the moment-expansion method. While exact results suggest a divergent spectrum width for ferromagnetic spin configurations, numerical calculations indicate a finite spectrum width for antiferromagnetic and random spin configurations. The spectrum widths for antiferromagnetic and random spin configurations are 5.6568±0.0001 and 10±2, respectively.

Y. S. Yang

1992-08-01T23:59:59.000Z

196

Magnetic Interactions in the Geometrically Frustrated Triangular Lattice Antiferromagnet CuFeO2  

SciTech Connect

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.

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

197

Magnetic Interaction in the Geometrically Frustrated Triangular LatticeAntiferromagnet CuFeO2  

SciTech Connect

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.

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

198

Persistence of magnons in a site-diluted dimerized frustrated antiferromagnet  

SciTech Connect

We present inelastic neutron scattering and thermodynamic measurements characterizing the magnetic excitations in a disordered non-magnetic substituted spin-liquid antiferromagnet. The parent compound Ba3Mn2O8 is a dimerized, quasi-two-dimensional geometrically frustrated quantum disordered antiferromagnet. We substitute this compound with non-magnetic vanadium for the S = 1 manganese atoms, Ba3(Mn1-xVx)2O8, and find that the singlet-triplet excitations which dominate the spectrum of the parent compound persist for the full range of substitution examined, x = 0.02 to 0.3. We also observe additional low-energy magnetic fluctuations which are enhanced at the greatest substitution values. These excitations may be a precursor to a low-temperature random singlet phase which may exist in Ba3(Mn1-xVx)2O8.

Stone, Matthew B [ORNL; Podlesnyak, Andrey A [ORNL; Ehlers, Georg [ORNL; Huq, Ashfia [ORNL; Samulon, Eric C [Stanford University; Shapiro, Max C [Stanford University; Fisher, Ian R [Stanford University

2011-01-01T23:59:59.000Z

199

Crystal structure dependence of antiferromagnetic coupling in Fe/Si multilayers  

SciTech Connect

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.

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

1995-04-01T23:59:59.000Z

200

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

SciTech Connect

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.

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

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Bifurcation to vortex solutions in superconducting lms  

E-Print Network (OSTI)

) and the geometry of the sample. Typically, a type I superconductor will change phase by means of phase boundaries superconductors the phase change is more grad- ual, with the superconductor #12;rst forming a mixed state in which-nonlinear stability analysis is performed, and the possible responses of the material are classi#12;ed. Finally

Chapman, Jon

202

Vortex properties in superconducting Nb/Pd multilayers  

Science Journals Connector (OSTI)

We have investigated the upper critical magnetic field Hc2, the critical current density Jc, and the pinning force Fp in sputtered Nb/Pd multilayers, varying the temperatures T, the Pd thicknesses dPd and the magnetic field H orientation (parallel and perpendicular to the plane of the sample). In perpendicular fields, the vortex dynamics was strongly influenced by grain-boundary pinning. In parallel fields, a peak was observed in the Jc(H) curves for samples with Pd thicknesses dPd>100 Å. After comparing the experimental results with the existing theories, we have related the presence of this peak effect to the matching of vortex kinks with the layered artificial structure.

C. Coccorese; C. Attanasio; L. V. Mercaldo; M. Salvato; L. Maritato; J. M. Slaughter; C. M. Falco; S. L. Prischepa; B. I. Ivlev

1998-04-01T23:59:59.000Z

203

Higher Derivative Corrections to Non-Abelian Vortex Effective Theory  

E-Print Network (OSTI)

We give a systematic method to calculate higher derivative corrections to low-energy effective theories of solitons, which are in general non-linear sigma models on the moduli spaces of the solitons. By applying it to the effective theory of a single BPS non-Abelian vortex in U(N) gauge theory with N fundamental Higgs fields, we obtain four derivative corrections to the effective sigma model on the moduli space C \\times CP^{N-1}. We compare them with the Nambu-Goto action and the Faddeev-Skyrme model. We also show that Yang-Mills instantons/monopoles trapped inside a non-Abelian vortex membrane/string are not modified in the presence of higher derivative terms.

Minoru Eto; Toshiaki Fujimori; Muneto Nitta; Keisuke Ohashi; Norisuke Sakai

2012-04-03T23:59:59.000Z

204

Precession of a single vortex line in superfluid B3  

Science Journals Connector (OSTI)

This paper reports the discovery of a new vortex phenomenon in superfluid B3. A single filament of quantized vortex line precesses as a solid body around a wire extending along the axis of a cylinder. The precession frequency equals the angular velocity of the apparatus at which the presence of a single quantum of circulation minimizes the system’s free energy. The period of precession is related to the circulation quantum and the dimensions of the apparatus. Thus a measurement of the precession period is an accurate determination of the quantum unit. We find ?=(1.020±0.03)h/2m3, where m3 is the mass of the He3 atom.

R. J. Zieve; Yu. Mukharsky; J. D. Close; J. C. Davis; R. E. Packard

1992-03-02T23:59:59.000Z

205

MHK Technologies/Vortex Oscillation | Open Energy Information  

Open Energy Info (EERE)

Oscillation Oscillation < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Vortex Oscillation.jpg Technology Profile Primary Organization Vortex Oscillation Technology Ltd Technology Resource Click here Current Technology Type Click here Attenuator Technology Readiness Level Click here TRL 1 3 Discovery Concept Def Early Stage Dev Design Engineering Technology Description If cylinder or another body is fixed on a moving bonding this force can set the body or its separate parts into oscillation e g elastic slat If the system of mechanical energy output is organized correctly this device can be considered as generator Technology Dimensions Device Testing Date Submitted 08:12.7 << Return to the MHK database homepage Retrieved from

206

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

207

Coherence Current, Coherence Vortex, and the Conservation Law of Coherence  

Science Journals Connector (OSTI)

Introducing scalar and vector densities for a mutual coherence function, we present a new conservation law for optical coherence of scalar wave fields in the form of a continuity equation. This coherence conservation law provides new insights into topological phenomena for the complex coherence function. Some properties related to the newly introduced coherence vector density, such as a circulating coherence current associated with a coherence vortex, are investigated both theoretically and experimentally for the first time.

Wei Wang and Mitsuo Takeda

2006-06-08T23:59:59.000Z

208

Transient vortex events in the initial value problem for turbulence  

E-Print Network (OSTI)

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.

Darryl D. Holm; Robert M. Kerr

2001-10-19T23:59:59.000Z

209

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

E-Print Network (OSTI)

. . . . . . . . . . . . . . . . . . . . . 14 III.1. Quasi-particles in quantum liquids . . . . . . . . . . . 15 III.2. Superfluidity . . . . . . . . . . . . . . . . . . . . . . . 16 III.2.1. Wave function of the Bose superfluid . . . . . . 17 III.3. Superfluidity of a Fermi gas... . . . . . . . . . . . . . . . 20 III.3.1. Wave function of the superfluid Fermi gas . . . 23 IV GINZBURG-LANDAU THEORY . . . . . . . . . . . . . . . . . 26 IV.1. Second-order phase transitions and critical phenomena 26 IV.2. Landau?s theory of second-order phase transition...

Kim, Sangbum

2006-04-12T23:59:59.000Z

210

Coherence Holography and Spatial Frequency Comb for 3-D Coherence Imaging and Coherence Vortex Generation  

Science Journals Connector (OSTI)

The principle and the applications of a recently proposed unconventional holography technique, coherence holography, applied for coherence vortex generation, and a related technique...

Takeda, Mitsuo; Wang, Wei; Duan, Zhihui; Miyamoto, Yoko; Rosen, Joseph

211

Vortex shedding from square plates near a ground plane: an experimental study.  

E-Print Network (OSTI)

??Vortex shedding frequencies were obtained experimentally for square plates near a ground plane in the Texas Tech wind tunnel. These frequencies, in the form of… (more)

Matty, Rosemary Ricohermoso

1979-01-01T23:59:59.000Z

212

Rotational Doppler-effect due to selective excitation of vector-vortex field in optical fiber  

Science Journals Connector (OSTI)

Experimental demonstration of rotational Doppler-effect due to direct and simultaneous excitation of orthogonal elliptically-polarized fundamental and vortex modes in a two-mode...

Inavalli, V V G Krishna; Viswanathan, Nirmal K

2011-01-01T23:59:59.000Z

213

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

SciTech Connect

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.

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

214

Effect of localized antiferromagnetic phases at interfaces between AlOx insulating barriers and Co50Fe50 electrodes in magnetic tunnel junctions  

Science Journals Connector (OSTI)

Localized antiferromagnetic (LAFM) phases at interfaces between AlOx insulating barriers and CoFe bottom electrodes were investigated. The LAFM phases were induced by interdiffusion of oxygen atoms into the bottom electrode during oxidation process. Observation in x-ray photoelectron spectroscopy exhibits the significant LAFM phases of CoO and FeO at 783 eV and 711 eV, respectively. The LAFM couplings sensitively relevant to oxidation time are directly related to the coercivity field difference in a magnetoresistance (MR) curve. They also enhance the coercivity of a CoFe bottom electrode from 25 Oe up to 71.5 Oe, depending on oxidation time. These results explain well the better MR curves by a locally overoxidized state inside a CoFe bottom electrode.

Kap Soo Yoon; Jung Yup Yang; Won Jun Choi; Chae Ok Kim; Jin Pyo Hong; Hyun Jung Kim

2004-01-26T23:59:59.000Z

215

Doping evolution of antiferromagnetic order and structural distortion in LaFeAsO{sub 1-x}F{sub x}  

SciTech Connect

We use neutron scattering to study the structural distortion and antiferromagnetic (AFM) order in LaFeAsO{sub 1-x}F{sub x} as the system is doped with fluorine (F) to induce superconductivity. In the undoped state, LaFeAsO exhibits a structural distortion, changing the symmetry from tetragonal (space group P4/nmm) to orthorhombic (space group Cmma) at 155 K, and then followed by an AFM order at 137 K. Doping the system with F gradually decreases the structural distortion temperature, but suppresses the long range AFM order before the emergence of superconductivity. Therefore, while superconductivity in these Fe oxypnictides can survive in either the tetragonal or the orthorhombic crystal structure, it competes directly with static AFM order.

Huang, Q.; Lynn, J. W. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102 (United States); Zhao Jun [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1200 (United States); Chen, G. F.; Luo, J. L.; Wang, N. L. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100080 (China); Dai Pengcheng [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1200 (United States); Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393 (United States)

2008-08-01T23:59:59.000Z

216

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

E-Print Network (OSTI)

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 ...

Dahl, Jason (Jason Michael)

2008-01-01T23:59:59.000Z

217

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

E-Print Network (OSTI)

´ 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

Kunchur, Milind N.

218

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

SciTech Connect

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}

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

219

Modeling bubble-vortex interactions Modeling and simulation of multiple bubble entrainment and interactions with two  

E-Print Network (OSTI)

Modeling bubble-vortex interactions Modeling and simulation of multiple bubble entrainment, OR 97331. (Dated: 5 November 2010) 1 #12;Modeling bubble-vortex interactions Simulations of bubble direct numerical simulation whereas motion of subgrid bubbles is modeled using Lagrangian track- ing

Apte, Sourabh V.

220

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

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Series of phase transitions and multiferroicity in the quasi-two-dimensional spin-12 triangular-lattice antiferromagnet Ba3CoNb2O9  

Science Journals Connector (OSTI)

We have investigated the magnetic and electric ground states of a quasi-two-dimensional triangular lattice antiferromagnet (TLAF), Ba3CoNb2O9, in which the effective spin of Co2+ is 1/2. At zero field, the system undergoes a two-step transition upon cooling at TN2=1.36 K and TN1=1.10 K and enters a 120? ordered state. By applying magnetic fields, a series of spin states with fractions of the saturation magnetization Ms are observed. They are spin states with 1/3, 1/2, 2/3 (or 3/3) Ms. The ferroelectricity emerges in all spin states, either with collinear or noncollinear spin structure, which makes Ba3CoNb2O9 another unique TLAF exhibiting both a series of magnetic phase transitions and multiferroicity. We discuss the role of quantum fluctuations and magnetic anisotropy in contributing more complex phase diagram compared to its sister multiferroic TLAF compound Ba3NiNb2O9 [J. Hwang et al., Phys. Rev. Lett. 109, 257205 (2012)].

M. Lee; J. Hwang; E. S. Choi; J. Ma; C. R. Dela Cruz; M. Zhu; X. Ke; Z. L. Dun; H. D. Zhou

2014-03-24T23:59:59.000Z

222

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

E-Print Network (OSTI)

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

Dabiri, John O.

223

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

E-Print Network (OSTI)

, 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

Caliari, Marco

224

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

E-Print Network (OSTI)

. 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

Boyer, Edmond

225

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

E-Print Network (OSTI)

: http://scitation.aip.org/termsconditions. Downloaded to IP: 131.111.185.7 On: Thu, 09 Oct 2014 15:47:13 18Y. L. Iunin, Y. P. Kabanov, V. I. Nikitenko, X. M. Cheng, D. Clarke, O. A. Tretiakov, O. Tchernyshyov, A. J. Shapiro, R. D. Shull, and C. L. Chien... Dynamic selective switching in antiferromagnetically-coupled bilayers close to the spin reorientation transition A. Fernández-Pacheco, F. C. Ummelen, R. Mansell, D. Petit, J. H. Lee, H. J. M. Swagten, and R. P. Cowburn Citation: Applied Physics...

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

226

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

SciTech Connect

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.

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

227

Quantification of Magnetic Domain Disorder and Correlations in Antiferromagnetically Coupled Multilayers by Neutron Reflectometry  

Science Journals Connector (OSTI)

The in-plane correlation lengths and angular dispersion of magnetic domains in a transition metal multilayer have been studied using off-specular neutron reflectometry techniques. A theoretical framework considering both structural and magnetic disorder has been developed, quantitatively connecting the observed scattering to the in-plane correlation length and the dispersion of the local magnetization vector about the mean macroscopic direction. The antiferromagnetic domain structure is highly vertically correlated throughout the multilayer. We are easily able to relate the neutron determined magnetic domain dispersion to magnetization and magnetoresistance experiments.

Sean Langridge; Jörg Schmalian; C. H. Marrows; D. T. Dekadjevi; B. J. Hickey

2000-12-04T23:59:59.000Z

228

Ferromagnetism and antiferromagnetism of 3d-metal overlayers on metals  

Science Journals Connector (OSTI)

We report systematic calculations based on the full-potential linearized augmented-plane-wave method for the whole transition-metal series (V,Cr,Mn,Fe,Co,Ni) as overlayers on the Pd(001) surface. An energy analysis shows that Fe, Co, and Ni overlayers favor the ferromagnetic p(1×1) configuration, but V, Cr, and Mn, the antiferromagnetic c(2×2) superstructure. We conjecture that this result is a general trend which should also be found on the (001) surfaces of Pt and the noble metals.

S. Blügel; M. Weinert; P. H. Dederichs

1988-03-14T23:59:59.000Z

229

Quantum dynamics of a vortex in a Josephson junction  

SciTech Connect

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.

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

230

Collective Effects in Vortex Movements in Complex Plasmas  

Science Journals Connector (OSTI)

We study the onset and characteristics of vortices in complex (dusty) plasmas using two-dimensional simulations in a setup modeled after the PK-3 Plus laboratory. A small number of microparticles initially self-arranges in a monolayer around the void. As additional particles are introduced, an extended system of vortices develops due to a nonzero curl of the plasma forces. We demonstrate a shear-thinning effect in the vortices. Velocity structure functions and the energy and enstrophy spectra show that vortex flow turbulence is present that is in essence of the “classical” Kolmogorov type.

Mierk Schwabe, Sergey Zhdanov, Christoph Räth, David B. Graves, Hubertus M. Thomas, and Gregor E. Morfill

2014-03-19T23:59:59.000Z

231

Spontaneous vortex phase and pinning in ferromagnetic-superconducting systems  

E-Print Network (OSTI)

of epsilon10 as a function of rho0lambda for the case when n = 1, lambdaxi = 10,R1 = lambda,R2 = 2lambda and deltam = 10. . . . . . . . . . . . . . . 31 ix FIGURE Page 12 A superconducting thin film pierced by a ferromagnetic nano rod of radius R, length L... circle of radius rho0 that depends on the radii and magnetization per unit area of the annulus, and on the SC pene- tration depth lambda. In section five I focus on pinning and spontaneous vortex creation by a ferromagnetic rod which penetrates...

Kayali, Mohammad Amin

2004-09-30T23:59:59.000Z

232

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

SciTech Connect

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.

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

2014-01-31T23:59:59.000Z

233

Spin liquid in a single crystal of the frustrated diamond lattice antiferromagnet CoAl2O4  

Science Journals Connector (OSTI)

We study the evidence for spin liquid in the frustrated diamond lattice antiferromagnet CoAl2O4 by means of single-crystal neutron scattering in zero and applied magnetic fields. The magnetically ordered phase appearing below TN=8 K remains nonconventional down to 1.5 K. The magnetic Bragg peaks at the q=0 positions are broad and their line shapes have strong Lorentzian contributions. Additionally, the peaks are connected by weak diffuse streaks oriented along the ?111? directions. The observed short-range magnetic correlations are explained within the spiral spin-liquid model. The specific shape of the energy landscape of the system, with an extremely flat energy minimum around q=0 and many low-lying excited spiral states with q=?111?, results in thermal population of this manifold at finite temperatures. The agreement between the experimental results and the spiral spin-liquid model is only qualitative, indicating that microstructure effects might be important to achieve quantitative agreement. Application of a magnetic field significantly perturbs the spiral spin-liquid correlations. The magnetic peaks remain broad but acquire more Gaussian line shapes and increase in intensity. The 1.5 K static magnetic moment increases from 1.58 ?B/Co at zero field to 2.08 ?B/Co at 10 T. The magnetic excitations appear rather conventional at zero field. Analysis using classical spin-wave theory yields values of the nearest- and next-nearest-neighbor exchange parameters J1=0.92(1) meV and J2=0.101(2) meV and an additional anisotropy term D=?0.0089(2) meV for CoAl2O4. In the presence of a magnetic field, the spin excitations broaden considerably and become nearly featureless at the zone center.

O. Zaharko; N. B. Christensen; A. Cervellino; V. Tsurkan; A. Maljuk; U. Stuhr; C. Niedermayer; F. Yokaichiya; D. N. Argyriou; M. Boehm; A. Loidl

2011-09-06T23:59:59.000Z

234

Moving vortex phases, dynamical symmetry breaking, and jamming for vortices in honeycomb pinning arrays  

SciTech Connect

We show using numerical simulations that vortices in honeycomb pinning arrays can exhibit a remarkable variety of dynamical phases that are distinct from those found for triangular and square pinning arrays. In the honeycomb arrays, it is possible for the interstitial vortices to form dimer or higher n-mer states which have an additional orientational degree of freedom that can lead to the formation of vortex molecular crystals. For filling fractions where dimer states appear, a dynamical symmetry breaking can occur when the dimers flow in one of two possible alignment directions. This leads to transport in the direction transverse to the applied drive. We show that dimerization produces distinct types of moving phases which depend on the direction of the driving force with respect to the pinning lattice symmetry. When the dimers are driven along certain directions, a reorientation of the dimers can produce a jamming phenomenon which results in a strong enhancement in the critical depinning force. The jamming can also cause unusual effects such as an increase in the critical depinning force when the size of the pinning sites is reduced.

Reichhardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

235

Random center vortex lines in continuous 3D space-time  

E-Print Network (OSTI)

We present a model of center vortices, represented by closed random lines in continuous 2+1- dimensional space- time. These random lines are modeled as being piece-wise linear and an ensemble is generated by Monte Carlo methods. The physical space in which the vortex lines are defined is a cuboid with periodic boundary conditions. Besides moving, growing and shrinking of the vortex configuration, also reconnections are allowed. Our ensemble therefore contains not a fixed, but a variable number of closed vortex lines. This is expected to be important for realizing the deconfining phase transition. Using the model, we study both vortex percolation and the potential V (R) between quark and anti-quark as a function of distance R at different vortex densities, vortex segment lengths, reconnection conditions and at different temperatures. We have found three deconfinement phase transitions, as a function of density, as a function of vortex segment length, and as a function of temperature. The model reproduces the qualitative features of confinement physics seen in SU(2) Yang-Mills theory.

Roman Höllwieser; Derar Altarawneh; Michael Engelhardt

2014-11-26T23:59:59.000Z

236

Critical line of an anisotropic Ising antiferromagnet on square and honeycomb lattices Xian-Zhi Wang and Jai Sam Kim  

E-Print Network (OSTI)

Critical line of an anisotropic Ising antiferromagnet on square and honeycomb lattices Xian line of an anisotropic Ising antiferro- magnet on two-dimensional square and honeycomb lattices. We physics is the Ising model in nonzero magnetic field except at one dimension 1,2 . We do not have

Kim, Jai Sam

237

Vortex and gap generation in gauge models of graphene  

E-Print Network (OSTI)

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.

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

2010-12-21T23:59:59.000Z

238

Antiferromagnetic spin excitations in single crystals of nonsuperconducting Li$_{1-x}$FeAs  

SciTech Connect

We use neutron scattering to determine spin excitations in single crystals of nonsuperconducting Li1 xFeAs throughout the Brillouin zone. Although angle resolved photoemission experiments and local density approximation calculations suggest poor Fermi surface nesting conditions for antiferromagnetic (AF) order, spin excitations in Li1 xFeAs occur at the AF wave vectors Q = (1,0) at low energies, but move to wave vectors Q = ( 0.5, 0.5) near the zone boundary with a total magnetic bandwidth comparable to that of BaFe2As2. These results reveal that AF spin excitations still dominate the low-energy physics of these materials and suggest both itinerancy and strong electron-electron correlations are essential to understand the measured magnetic excitations.

Wang, Meng [ORNL; Wang, X.C. [Beijing National Laboratory for Condensed Matter Physics/Chinese Academy of Scie; Abernathy, Douglas L [ORNL; Harriger, Leland W [ORNL; Luo, H.Q. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics; Zhao, Yang [ORNL; Lynn, J. W. [National Institute of Standards and Technology (NIST); Liu, Q.Q. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics; Jin, C.Q. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics; Fang, Chen [Purdue University; Hu, Jiangping [Purdue University and Chinese Academy of Sciences; Dai, Pengcheng [University of Tennessee, Knoxville (UTK)

2011-01-01T23:59:59.000Z

239

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

SciTech Connect

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.

Analytis, J.G.

2010-05-26T23:59:59.000Z

240

CFD Numerical Simulation of Vortex-Induced Vibration of a Stay Cable under a Wind Profile  

Science Journals Connector (OSTI)

VIV (Vortex-induced vibration) of a stay cable subjected to a wind profile is numerically simulated through combining CFD ... numerical model. Under a profile of mean wind speed, unsteady aerodynamic lift coeffic...

Wenli Chen; Hui Li

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


241

Optimal Excitation of Asymmetric Perturbations on an Axisymmetric Barotropic Vortex: A linear Singular Value Analysis  

Science Journals Connector (OSTI)

Singular vectors on a barotropic circular vortex consisting of three regions of piecewise-constant vorticity are investigated under the L2-norm to reveal the shape and growth rate of possible perturbations that may contribute to the formation of ...

Toshihisa Itano

242

Dynamical mass of a quantum vortex in a Josephson junction array  

SciTech Connect

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}

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

243

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

NLE Websites -- All DOE Office Websites (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... ,...

244

Ultraviolet vortex generation using periodically bonded ?-BaB2O4 device  

Science Journals Connector (OSTI)

This paper describes the first demonstration of ultraviolet (266nm) vortex generation using the combination of a frequency-doubled nanosecond green laser, a spiral phase plate, and a...

Sasaki, Yuta; Koyama, Mio; Miyamoto, Katsuhiko; Ariga, Yoshimi; Onda, Tomomi; Shoji, Ichiro; Omatsu, Takashige

2014-01-01T23:59:59.000Z

245

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

E-Print Network (OSTI)

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...

Chitwood, James Scott

2012-06-07T23:59:59.000Z

246

Application of fiber Bragg grating based strain sensor in pipeline vortex-induced vibration measurement  

Science Journals Connector (OSTI)

The vortex-induced vibrations (VIV) is an important topic of ... of different methods have been applied to the measurement of VIV, especially for the elongated, ... in stainless steel tubes were applied to the measurement

Liang Ren; ZiGuang Jia; Michael Siu Chun Ho…

2014-09-01T23:59:59.000Z

247

Resonant amplification of vortex-core oscillations by coherent magnetic-field pulses  

E-Print Network (OSTI)

structure of magnetic vortex cores. Science 298, 577–580 (D. A. et al. Magnetic domain-wall logic. Science 309, 1688 (L. Magnetic domain-wall racetrack memory. Science 320, 190–

Yu, Young-Sang

2014-01-01T23:59:59.000Z

248

The Roles of Vortex Rossby Waves in Hurricane Secondary Eyewall Formation  

Science Journals Connector (OSTI)

A high-resolution, full-physics model initiated with an idealized tropical cyclone–like vortex is used to simulate and investigate the secondary eyewall formation. The beta skirt axisymmetrization (BSA) hypothesis previously proposed is examined ...

Xin Qiu; Zhe-Min Tan; Qingnong Xiao

2010-06-01T23:59:59.000Z

249

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

E-Print Network (OSTI)

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...

Fox, Amanda Katherine

2012-06-07T23:59:59.000Z

250

Vortex Induced Vibrations of cylinders : experiments in reducing drag force and amplitude of motion  

E-Print Network (OSTI)

Reducing the deleterious effect of Vortex Induced Vibrations (VIV) in marine risers is an important task for ocean engineers; and many competing factors exist in the design of VIV suppression devices. This thesis explores ...

Farrell, David Emmanuel

2007-01-01T23:59:59.000Z

251

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

E-Print Network (OSTI)

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...

Nelson, Carter T.

2012-06-07T23:59:59.000Z

252

An adaptive mesh method for the simulation of Blade Vortex Interaction  

E-Print Network (OSTI)

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...

Kim, Kyu-Sup

2012-06-07T23:59:59.000Z

253

MEC E 638 VORTEX FLOWS Winter 2014 LARGE-SCALE STRUCTURES IN TURBULENCE PROF L. SIGURDSON  

E-Print Network (OSTI)

to find the characteristic vortex structures; to read the literature, nomenclature, terminology. TOPICS: Professor Lorenz Sigurdson, 5-1B Mech Eng Bldg, lorenz@ualberta.ca, http://websrv.mece.ualberta.ca/intranet

Flynn, Morris R.

254

Visualization of Intricate Flow Structures for Vortex Breakdown Analysis Xavier Tricoche  

E-Print Network (OSTI)

Hansen University of Utah Figure 1: Vortex breakdown bubble in numerical simulation of a cylindrical to study their impact on flight stability. Yet, to fully exploit the huge amount of information contained

Utah, University of

255

Annular Vortex Generation for Inertial Fusion Energy Beam-Line Protection  

SciTech Connect

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.

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

2003-05-15T23:59:59.000Z

256

High-frequency vortex dynamics and dissipation of high-temperature superconductors  

Science Journals Connector (OSTI)

The high-frequency vortex dynamics of high-temperature superconductors near the flux-line depinning threshold is investigated based on a thermally activated flux-flow (TAFF) model. Dissipation due to vortex motion driven by a microwave electromagnetic field is studied as a function of the frequency, temperature, dc magnetic field, and microwave power. The generalized TAFF model is also compared to the conventional flux-creep theory and is found qualitatively consistent.

N.-C. Yeh

1991-01-01T23:59:59.000Z

257

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

E-Print Network (OSTI)

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...

Wood, Vincent Tunstall

2012-06-07T23:59:59.000Z

258

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

E-Print Network (OSTI)

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.

Timothy D. Andersen; Chjan C. Lim

2006-11-19T23:59:59.000Z

259

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

SciTech Connect

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.

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

260

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

SciTech Connect

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.

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

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Evolution of antiferromagnetic susceptibility under uniaxial pressure in Ba(Fe1?xCox)2As2  

Science Journals Connector (OSTI)

Neutron diffraction measurements are presented measuring the responses of both magnetic and structural order parameters of parent and lightly Co-doped Ba(Fe1?xCox)2As2 under the application of uniaxial pressure. We find that the uniaxial pressure induces a thermal shift in the onset of antiferromagnetic order that grows as a percentage of TN as Co doping is increased and the superconducting phase is approached. Additionally, as uniaxial pressure is increased within parent and lightly doped Ba(Fe1?xCox)2As2 on the first-order side of the tricritical point, we observe a decoupling between the onsets of the orthorhombic structural distortion and antiferromagnetism. Our findings place needed constraints on models exploring the nematic susceptibility of the bilayer pnictides in the tetragonal, paramagnetic regime.

Chetan Dhital; Tom Hogan; Z. Yamani; Robert J. Birgeneau; W. Tian; M. Matsuda; A. S. Sefat; Ziqiang Wang; Stephen D. Wilson

2014-06-06T23:59:59.000Z

262

Spontaneous Spin-lattice Coupling in the Geometrically Frustrated Triangular Lattice antiferromagnet CuFeO2  

SciTech Connect

We use high-resolution synchrotron x-ray and neutron diffraction to study the geometrically frustrated triangular lattice antiferromagnet CuFeO{sub 2}. On cooling from room temperature, CuFeO{sub 2} undergoes two antiferromagnetic phase transitions with incommensurate and commensurate magnetic order at T{sub N1} = 14 K and T{sub N2} = 11 K, respectively. The occurrence of these two magnetic transitions is accompanied by second- and first-order structural phase transitions from hexagonal to monoclinic symmetry. Application of a 6.9 T magnetic field lowers both transition temperatures by {approx}1 K, and induces an additional incommensurate structural modulation in the temperature region where the field-driven ferroelectricity occurs. These results suggest that a strong magneto-elastic coupling is intimately related to the multiferroic effect.

Ye, Feng [ORNL; Ren, Y. [Argonne National Laboratory (ANL); Huang, Q. [National Institute of Standards and Technology (NIST); Fernandez-Baca, Jaime A [ORNL; Dai, Pengcheng [ORNL; Lynn, J. W. [National Institute of Standards and Technology (NIST); Kimura, T. [Los Alamos National Laboratory (LANL)

2006-01-01T23:59:59.000Z

263

Numerical simulation of a viscous vortex ring interaction with a density interface  

SciTech Connect

When a vortex-dominated flow interacts with a sharp density interface, the dynamics are characterized by the interaction of baroclinically generated vorticity with the already existing vorticity field. This can be seen in many natural and technology settings; examples are the interaction of a ship or submarine wake with a thermocline, the collision of a buoyant thermal with a temperature inversion, and the interaction of a vortex flow with a flame front. This problem also serves as a generic model for turbulent mixing and entrainment processes across sharp density interfaces. The interaction between vortices and a free surface, with corresponds to the case where the density jump is very large, has been studied fairly extensively, both experimentally and computationally. By comparison, the literature for the more general case of vortex pairs and rings interacting with sharp density interfaces is relatively sparse. Experiments and numerical studies have been performed, but the numerical simulations were confined primarily to vortex pairs, restricted to the inviscid case, and the effect of density variation modeled under the Boussinesq approximation. The experiments were also confined to the Boussinesq regime. In this paper, we study the motion of a vortex ring in a sharply stratified, viscous fluid via a numerical solution of the full Navier-Stokes equations with finite-amplitude density variation. both Boussinesq and non-Boussinesq flow regimes will be studied, the effect of viscosity on the interaction will be examined, and three-dimensional aspects of the motion will be addressed, such as Widnall instability of the vortex ring and vortex reconnection at the interface.

Marcus, D.L.; Bell, J.B.

1990-10-01T23:59:59.000Z

264

Magnetorotational instability, current relaxation, and current-vortex sheet  

SciTech Connect

The conjugate effect of current relaxation and of current-vortex sheet formation on the magnetorotational instability is explored in a conducting fluid. It is found that the relative amplification of the magnetic viscosity from marginal stability to the instability determined by the maximum growth rate is around 924% when resistive effects dominate, while the corresponding quantity is around 220% in the ideal limit. This shows that the conjugate influence is much more efficient to amplify the magnetic viscosity than just the effect due to the standard magnetic tension. It is also found that the magnitude of the magnetic viscosity is effectively enhanced by the conjugate influence. The results presented here may contribute to the understanding of the various processes that play a significant role in the mechanism of anomalous viscosity observed in Keplerian disks. It is argued that the new effect shall be relevant in thin accretion disks. It is also mentioned that the proposed formulation may be of interest for some theories of magnetic reconnection. Possible extensions of this work are suggested.

Silveira, F. E. M. [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia, 166, CEP 09210-170, Bairro Bangu, Santo André, SP (Brazil)] [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia, 166, CEP 09210-170, Bairro Bangu, Santo André, SP (Brazil); Galvão, R. M. O. [Instituto de Física, Universidade de São Paulo, Rua do Matão, Travessa R, 187, CEP 05508-090, Cidade Universitária, São Paulo, SP (Brazil)] [Instituto de Física, Universidade de São Paulo, Rua do Matão, Travessa R, 187, CEP 05508-090, Cidade Universitária, São Paulo, SP (Brazil)

2013-08-15T23:59:59.000Z

265

Vortex Dynamics for the Ginzburg-Landau-Schrödinger Equation  

E-Print Network (OSTI)

The initial value problem for the Ginzburg-Landau-Schr\\"odinger equation is examined in the $\\epsilon \\rightarrow 0$ limit under two main assumptions on the initial data $\\phi^\\epsilon$. The first assumption is that $\\phi^\\epsilon$ exhibits $m$ distinct vortices of degree $\\pm 1$; these are described as points of concentration of the Jacobian $[J\\phi^\\epsilon]$ of $\\phi^\\epsilon$. Second, we assume energy bounds consistent with vortices at the points of concentration. Under these assumptions, we identify ``vortex structures'' in the $\\epsilon \\rightarrow 0$ limit of $\\phi^\\epsilon$ and show that these structures persist in the solution $u^\\epsilon(t)$ of $GLS_\\epsilon$. We derive ordinary differential equations which govern the motion of the vortices in the $\\epsilon \\rightarrow 0$ limit. The limiting system of ordinary differential equations is a Hamitonian flow governed by the renormalized energy of Bethuel, Brezis and H\\'elein. Our arguments rely on results about the structural stability of vortices which are proved in a separate paper.

James Ellis Colliander; Robert L. Jerrard

1997-12-12T23:59:59.000Z

266

Tuning the competition between ferromagnetism and antiferromagnetism in a half-doped manganite through magnetoelectric coupling  

SciTech Connect

We investigate the possibility of controlling the magnetic phase transition of the heterointerface between a half-doped manganite La0:5Ca0:5MnO3 and a multiferroic BiFeO3 (BFO) through magnetoelectric coupling. Using macroscopic magnetometry and element-selective x-ray magnetic circular dichroism at the Mn and Fe L edges, we discover that the ferroelectric polarization of BFO controls simultaneously the magnetization of BFO and La0.5Ca0.5MnO3 (LCMO). X-ray absorption spectra at the oxygen K edge and linear dichroism at the Mn L edge suggest that the interfacial coupling is mainly derived from the superexchange between Mn and Fe t2g spins. The combination of x-ray absorption spectroscopy and mean-field theory calculations reveals that the d-electron modulation of Mn cations changes the magnetic coupling in LCMO, which controls the enhanced canted moments of interfacial BFO via the interfacial coupling. Our results demonstrate that the competition between ferromagnetic and antiferromagnetic instability can be modulated by an electric field at the heterointerface, providing another pathway for the electrical field control of magnetism.

Yi, Di [University of California; Liu, Jian [University of California, Berkeley & LBNL; Okamoto, Satoshi [ORNL; Jagannatha, Suresha [Lawrence Berkeley National Laboratory (LBNL); Chen, Yi-Chun [National Cheng Kung University, Tainan, Taiwan; Yu, Pu [Tsinghua University; Chu, Ying-Hao [National Chiao Tung University, Hsinchu, Taiwan; Arenholz, Elke [Lawrence Berkeley National Laboratory (LBNL); Ramesh, Ramamoorthy [University of California, Berkeley

2013-01-01T23:59:59.000Z

267

Electronic transport and antiferromagnetism in the layered compound BaCoS2  

Science Journals Connector (OSTI)

BaCoS2 is a Mott insulator with a Neél temperature (TN) close to room temperature. In the ordered antiferromagnetic phase, the magnetic moments are confined in the Co2S2 planes, and arranged in alternatingly directed ferromagnetic chains. We report on resistivity and thermopower measurements and on room-temperature cell constants of samples of BaCoSz with nominal sulfur content 1.9<~z<~2.1. We discuss the effect of sulfur content on cell constants and band filling. The main observation is a crossover from activated electronic transport at high temperatures, to high resistivity almost independent of temperature, and accompanied by a vanishingly small thermopower, at low temperatures (far below TN). We interpret the transport mechanism in the low-temperature regime as tunneling in the Co2S2 planes, to nearest neighbors along the ferromagnetic chains and to next-nearest neighbors in the perpendicular direction, or alternatively to nearest neighbors along the ferromagnetic chains with conducting inclusions acting as shorts.

B. Fisher; J. Genossar; L. Patlagan; G. M. Reisner; A. Knizhnik

1999-04-01T23:59:59.000Z

268

UA/ORNL Collaboration: Neutron Scattering Studies of Antiferromagnetic Films, Final Report  

SciTech Connect

The work reported here was a collaborative project between the research groups of Dr. J.L. Robertson at Oak Ridge National Laboratory and Dr. G.J. Mankey at the University of Alabama. The main thrust is developing neutron optical devices and materials for the study of magnetic thin films and interfaces. The project is particularly timely, since facility upgrades are currently underway at the High Flux Isotope Reactor. A new neutron optical device, a multicrystal analyzer, was designed and built to take maximum advantage of the increased flux that the upgraded beamlines at HFIR will provide. This will make possible detailed studies of the magnetic structure of thin films, multilayers, and interfaces that are not feasible at present. We performed studies of the antiferromagnetic order in thin films and crystals using neutron scattering, determined magnetic structures at interfaces with neutron reflectometry and measured order in magnetic dispersions using small angle neutron scattering. The collaboration has proved fruitful: generating eleven publications, contributing to the training of a postdoc who is now on staff at the High Flux Isotope Reactor and providing the primary support for two recent Ph.D. recipients. The collaboration is still vibrant, with anticipated implementation of the multicrystal analyzer on one of the new cold source beamlines at the High Flux Isotope Reactor.

Mankey, Gary J.

2006-07-26T23:59:59.000Z

269

Increasing liquid hydrocarbon recovery from natural gas: Evaluation of the vortex-tube device  

SciTech Connect

The vortex-tube device provides a useful addition to the range of equipment available to the gas industry. It has been shown that the use of vortex-tube equipment permits improved separation in comparison with a Joule-Thomson system, without entering into the cost and complexity of a true isentropic system such as a turbo-expander unit. The comparative advantage of the vortex tube depends upon the inlet conditions of the gas and the pressure drop that is available. An optimum pressure drop of 25--35% of the inlet gas pressure has been confirmed in practice. Although not yet tested on operating plant, it is expected that a loss of performance of vortex-tube units will occur for inlet liquid-to-gas ratios of greater than 20%. Units with up to 5% liquid at the inlet have been successfully operated showing that a single phase gas at the unit inlet is not essential. It is expected that future application of vortex tube units will be concentrated where performance improvements over Joule-Thomson units, at low capital cost, are required.

Hajdik, B. [CBS Engineering, Houston, TX (United States); Steinle, J. [BEB Erdoel and Erdgas GmbH, Hannover (Germany); Lorey, M. [Filtan Analgenbau GmbH, Langenselbold (Germany); Thomas, K. [Falk and Thomas Engineering GmbH, Wettenberg (Germany)

1997-12-31T23:59:59.000Z

270

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

SciTech Connect

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.

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

2006-06-22T23:59:59.000Z

271

Numerical Simulation of the Meso-? Scale Structure and Evolution of the 1977 Johnstown Flood. Part II: Inertially Stable Warm-Core Vortex and the Mesoscale Convective Complex  

Science Journals Connector (OSTI)

A mesoscale warm-core vortex associated with the mesoscale convective complex (MCC) that produced the 1977 Johnstown flood is examined using a three-dimensional nested-grid model simulation of the flood episode. In the simulation, the vortex ...

Da-Lin Zhang; J. Michael Fritsch

1987-09-01T23:59:59.000Z

272

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

E-Print Network (OSTI)

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

Andrei, Eva Y.

273

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

E-Print Network (OSTI)

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...

Oliva, Sergio Eduardo

2012-06-07T23:59:59.000Z

274

Counter-rotating vortex patches in shear: a model of the effect of wind shear on aircraft trailing vortices  

Science Journals Connector (OSTI)

...significantly a following passenger-containing aircraft and cause an accident. For example, the vortex wake of a Boeing 747 can rotate a Boeing 737 through 45 . This problem is called the trailing-vortex hazard, and since the trailing vortices can...

2002-01-01T23:59:59.000Z

275

Slowing of vortex rings by development of Kelvin waves Robert E. Hershberger, Diogo Bolster, and Russell J. Donnelly*  

E-Print Network (OSTI)

of existence, their duration a problem of stability and if there are several we have a problem of vortex mecha- nism is that the bubble loses impulse as the radius of the ring grows due to viscous decay of circulation 6 . A further theory suggests that the vortex bubble the ambient fluid car- ried along

Bolster, Diogo

276

Observation of Hybrid Soliton Vortex-Ring Structures in Bose-Einstein Condensates Naomi S. Ginsberg,1,* Joachim Brand,2  

E-Print Network (OSTI)

-Einstein condensates. We examine both their creation via soliton-vortex collisions and their subsequent development into vortex rings (VRs) [7,8] via the Kadomtsev-Petviashvili, or ``snake,'' instability [9]. In this Letter frequencies !z 2 21 Hz and !x !y 3:0!z in our 4-Dee magnetic trap [14]. We work at temperatures well below

Hau, Lene Vestergaard

277

Reduction of vortex induced forces and motion through surface roughness control  

DOE Patents (OSTI)

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.

Bernitsas, Michael M; Raghavan, Kamaldev

2014-04-01T23:59:59.000Z

278

Experimental study of vortex generators effects on low Reynolds number airfoils in turbulent flow  

Science Journals Connector (OSTI)

In the present work, we study the aerodynamic effects of triangular vortex generators, as passive flow control devices, placed on the upper surface of an airfoil submitted to a low Reynolds number turbulent flow. In the experiments, different configurations of those devices have been studied. An Eppler 387 airfoil was used. The tests were performed in a turbulent boundary layer wind tunnel using a two component aerodynamic balance and flow visualisation systems. Turbulent flow characterisation was made by means of hot wire anemometry. Calculations of local turbulent intensity as well as temporal and spatial turbulent scales were made. Vortex generators were located at 10% and 20% of the airfoil chord from the leading edge, modifying its angle of incidence refereed to the free stream. The results show changes in the aerodynamic section coefficients, C1, Cd and C1, for the different vortex generator configurations. Neither hysteresis effects, nor leading edge bubbles were found in the experiments.

Juan Sebastián Delnero; Julio Marañon Di Leo; Mauricio Ezequiel Camocardi; Mariano A. Martinez; Jorge L. Colman Lerner

2012-01-01T23:59:59.000Z

279

Novel vortex dynamics in untwinned YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} single crystals  

SciTech Connect

Magnetotransport measurements on a clean, untwinned YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} single crystal show that the vortex dynamics at temperatures just below the vortex lattice melting transition are highly dependent on the type of modulation of the probing current. While in the case of DC current the flux flow is disordered, the {open_quotes}shaking{close_quotes} of the vortex lattice by a square-wave current leads to a more uniform vortex motion. A small asymmetry ({approximately}10%) in the durations of the positive and negative parts of the square-wave period induces periodical oscillations of the voltage response amplitude. The period of oscillations ({approximately}100 s) is the same order of magnitude as the time needed for vortices to cross the sample (transit time). The authors relate the observed voltage oscillations to a periodically ordered vortex motion.

Gordeev, S.N.; Oussena, M.; Pinfold, S.; Langan, R.M. [Univ. of Southampton (United Kingdom)] [and others

1996-12-01T23:59:59.000Z

280

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

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.

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

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

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

SciTech Connect

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.

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

2001-10-01T23:59:59.000Z

282

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

E-Print Network (OSTI)

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...

Maynard, Ian Kenneth

2012-06-07T23:59:59.000Z

283

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

SciTech Connect

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.

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

284

Statistical Behavior of Formation Process of Magnetic Vortex State in Ni80Fe20 Nanodisks  

E-Print Network (OSTI)

This work was supported by the Director, Office of Science,Office of Basic Energy Sciences, Materials Sciences and

Im, Mi-Young

2011-01-01T23:59:59.000Z

285

Tropical cyclone genesis efficiency: mid-level versus bottom vortex Xuyang Ge and Tim Li  

E-Print Network (OSTI)

;4 1. Introduction Tropical cyclone (TC) genesis is the least understood phase in a TC life cycle is cyclogenesis in an environment with a mid-level vortex (EMV). An analysis of the WNP TC genesis in 2000 the QuikSCAT-derived surface wind observations, there was no sign

Li, Tim

286

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

E-Print Network (OSTI)

, 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

Kunchur, Milind N.

287

DETECTION OF VORTEX TUBES IN SOLAR GRANULATION FROM OBSERVATIONS WITH SUNRISE  

SciTech Connect

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.

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

288

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

E-Print Network (OSTI)

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

Zhang, Da-Lin

289

Sediment resuspension and erosion by vortex rings R. J. Munro,1,a  

E-Print Network (OSTI)

Sediment resuspension and erosion by vortex rings R. J. Munro,1,a N. Bethke,2 and S. B. Dalziel2 1; accepted 26 January 2009; published online 8 April 2009 Particle resuspension and erosion induced-ring propagation speed. The critical conditions for resuspension whereby particles are only just resuspended were

Dalziel, Stuart

290

Particle resuspension by an impacting vortex ring RICK J. MUNRO & STUART B. DALZIEL  

E-Print Network (OSTI)

Particle resuspension by an impacting vortex ring RICK J. MUNRO & STUART B. DALZIEL Department results from a set of visualization experiments conducted to analyse the hydrodynamic resuspension of particles from a thick horizontal sediment layer. The mechanism employed to produce the resuspension

Dalziel, Stuart

291

Vortex Ring Interaction with a Particle Layer: Implications for Sediment Transport  

E-Print Network (OSTI)

resuspension has been studied much less. This is an important mechanism, however, as it represents an integral conducted to study particle resuspension by vortex rings colliding with a particle bed. The dynamics at the resuspension onset are investigated, showing that the deformable particle bed resembles a free slip boundary

Dalziel, Stuart

292

Resuspension onset and crater erosion by a vortex ring interacting with a particle layer  

Science Journals Connector (OSTI)

This paper presents results from an experimental investigation of the interaction of a vortex ring with a particle layer. The flowdynamics during the onset of particle resuspension are analysed using particle image velocimetry while a light attenuation method provides accurate measurements of the final eroded crater shape. This work is a continuation of the research described in R. J. Munro N. Bethke and S. B. Dalziel “Sediment resuspension and erosion by vortex rings ” Phys. Fluids21 046601 (2009)10.1063/1.3083318 which focussed on the general resuspension onset dynamics and initial crater formation. Here we analyse the velocity induced by the vortex ring on the particle layer surface during the resuspension of particles for different particle sizes and the shape and size of the final craters that are formed by the impact of the vortex ring. We find that the boundary condition is characterised by a quasi-slip velocity at the particle layer surface independent of the particle size. The particle diameter and thus bed permeability is found to have a significant effect on the final crater characteristics.

N. Bethke; S. B. Dalziel

2012-01-01T23:59:59.000Z

293

Resuspension onset and crater erosion by a vortex ring interacting with a particle layer  

E-Print Network (OSTI)

Resuspension onset and crater erosion by a vortex ring interacting with a particle layer N. Bethke://pof.aip.org/features/most_downloaded Information for Authors: http://pof.aip.org/authors #12;PHYSICS OF FLUIDS 24, 063301 (2012) Resuspension onset layer. The flow dynamics during the onset of particle resuspension are analysed using particle image

Dalziel, Stuart

294

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

E-Print Network (OSTI)

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

Steffen, Michael

295

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

E-Print Network (OSTI)

`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

Zeldov, Eli

296

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

E-Print Network (OSTI)

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

Maccabe, Barney

297

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

298

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

E-Print Network (OSTI)

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

Yang, Jianke

299

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

E-Print Network (OSTI)

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...

Trosper, Jeffrey Randall

2012-06-07T23:59:59.000Z

300

Nanogenerator as an active sensor for vortex capture and ambient wind-velocity detection  

E-Print Network (OSTI)

and mechanical (wind, water flow, vibration, friction and body movement) energies are common in the ambientNanogenerator as an active sensor for vortex capture and ambient wind-velocity detection Rui Zhang principle, ambient wind-speed measurements with the NG are demonstrated. Due to the simple structure, high

Wang, Zhong L.

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Anomalous United States weather patterns accompanying Stratospheric Sudden Warming  

E-Print Network (OSTI)

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...

Douglas, Donald Albert

2012-06-07T23:59:59.000Z

302

Exchange-bias instability in a bilayer with an ion-beam imprinted stripe pattern of ferromagnetic/antiferromagnetic interfaces  

SciTech Connect

We have investigated the magnetization arrangement in an in-plane stripe pattern with alternating exchange-bias domains. The stripe pattern was produced by ion bombardment induced magnetic patterning, which changed locally the exchange-bias direction at the ferromagnet/antiferromagnet interface, but not the magnetic or antiferromagnetic properties of the Co{sub 70}Fe{sub 30} and Mn{sub 83}Ir{sub 17} layers, respectively. For the analysis of the magnetic domain structure evolution along the hysteresis loop we used a combination of experimental techniques: magneto-optical Kerr effect, Kerr microscopy, polarized neutron reflectometry, and off-specular scattering of polarized neutrons with polarization analysis. Instead of a perfect antiparallel alignment we found that the magnetization in neighboring stripes is periodically canted with respect to the stripe axis so that the net magnetization of the ferromagnetic film turns almost perpendicular to the stripes. At the same time the projection of the magnetization vector onto the stripe axis has a periodically alternating sign. The experimental observations are explained and quantitatively described within the frame of a phenomenological model, taking into account interfacial exchange bias, intralayer exchange energy, and uniaxial anisotropy. The model defines conditions which can be used for tailoring nano- and micro-patterned exchange-bias systems with different types of magnetic order.

Theis-Broehl, Katharina; Wolff, Maximilian; Westphalen, Andreas; Zabel, Hartmut; McCord, Jeffrey; Hoeink, Volker; Schmalhorst, Jan; Reiss, Guenther; Weis, Tanja; Engel, Dieter; Ehresmann, Arno; Ruecker, Ulrich; Toperverg, Boris P. [Department of Physics, Ruhr-University Bochum, D-44780 Bochum (Germany); Leibniz Institute for Solid State and Materials Research Dresden, Institute for Metallic Materials, Helmholtzstrasse 20, D-01169 Dresden (Germany); Department of Physics, University Bielefeld, Universitaetsstrasse 25, D-33615 Bielefeld (Germany); Institute of Physics and Centre for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Strasse 40, D-34132 Kassel (Germany); Institut fuer Festkoerperforschung, Forschungszentrum Juelich GmbH, D-52425 Juelich (Germany); Department of Physics, Ruhr-University Bochum, D-44780 Bochum, Germany, Institut Laue Langevin, Boite Postale 156, Grenoble 38000, France, and Petersburg Nuclear Physics Institute, Gatchina, 188300 St. Petersburg (Russian Federation)

2006-05-01T23:59:59.000Z

303

ALSNews Vol. 324  

NLE Websites -- All DOE Office Websites (Extended Search)

4 Print 4 Print Bioactive Glass Scaffolds for Bone Regeneration Natural materials are renowned for their unique combination of outstanding mechanical properties and exquisite microstructure. Researchers at Beamline 8.3.2 have created bioactive glass scaffolds that mirror nature's efficient materials and may provide a means for previously problematic bone regeneration in large, load-bearing limbs. Read more... Contact: Q. Fu Direct Imaging of Antiferromagnetic Vortex States Despite intensive activity in the study of ferromagnetic (FM) vortex states, there has been no direct observation of such states in antiferromagnetic (AFM) microstructures. Researchers have now taken the first direct images of two types of AFM vortex states, one of which has no FM analogue. Read more...

304

ALSNews Vol. 324  

NLE Websites -- All DOE Office Websites (Extended Search)

4 Print 4 Print Bioactive Glass Scaffolds for Bone Regeneration Natural materials are renowned for their unique combination of outstanding mechanical properties and exquisite microstructure. Researchers at Beamline 8.3.2 have created bioactive glass scaffolds that mirror nature's efficient materials and may provide a means for previously problematic bone regeneration in large, load-bearing limbs. Read more... Contact: Q. Fu Direct Imaging of Antiferromagnetic Vortex States Despite intensive activity in the study of ferromagnetic (FM) vortex states, there has been no direct observation of such states in antiferromagnetic (AFM) microstructures. Researchers have now taken the first direct images of two types of AFM vortex states, one of which has no FM analogue. Read more...

305

ALSNews Vol. 324  

NLE Websites -- All DOE Office Websites (Extended Search)

4 Print 4 Print Bioactive Glass Scaffolds for Bone Regeneration Natural materials are renowned for their unique combination of outstanding mechanical properties and exquisite microstructure. Researchers at Beamline 8.3.2 have created bioactive glass scaffolds that mirror nature's efficient materials and may provide a means for previously problematic bone regeneration in large, load-bearing limbs. Read more... Contact: Q. Fu Direct Imaging of Antiferromagnetic Vortex States Despite intensive activity in the study of ferromagnetic (FM) vortex states, there has been no direct observation of such states in antiferromagnetic (AFM) microstructures. Researchers have now taken the first direct images of two types of AFM vortex states, one of which has no FM analogue. Read more...

306

ALSNews Vol. 324  

NLE Websites -- All DOE Office Websites (Extended Search)

4 Print 4 Print Bioactive Glass Scaffolds for Bone Regeneration Natural materials are renowned for their unique combination of outstanding mechanical properties and exquisite microstructure. Researchers at Beamline 8.3.2 have created bioactive glass scaffolds that mirror nature's efficient materials and may provide a means for previously problematic bone regeneration in large, load-bearing limbs. Read more... Contact: Q. Fu Direct Imaging of Antiferromagnetic Vortex States Despite intensive activity in the study of ferromagnetic (FM) vortex states, there has been no direct observation of such states in antiferromagnetic (AFM) microstructures. Researchers have now taken the first direct images of two types of AFM vortex states, one of which has no FM analogue. Read more...

307

ALSNews Vol. 324  

NLE Websites -- All DOE Office Websites (Extended Search)

4 Print 4 Print Bioactive Glass Scaffolds for Bone Regeneration Natural materials are renowned for their unique combination of outstanding mechanical properties and exquisite microstructure. Researchers at Beamline 8.3.2 have created bioactive glass scaffolds that mirror nature's efficient materials and may provide a means for previously problematic bone regeneration in large, load-bearing limbs. Read more... Contact: Q. Fu Direct Imaging of Antiferromagnetic Vortex States Despite intensive activity in the study of ferromagnetic (FM) vortex states, there has been no direct observation of such states in antiferromagnetic (AFM) microstructures. Researchers have now taken the first direct images of two types of AFM vortex states, one of which has no FM analogue. Read more...

308

Tropical Cyclone Initialization with a Spherical High-Order Filter and an Idealized Three-Dimensional Bogus Vortex  

Science Journals Connector (OSTI)

A tropical cyclone initialization method with an idealized three-dimensional bogus vortex of an analytic empirical formula is presented for the track and intensity prediction. The procedure in the new method consists of four steps: the separation ...

In-Hyuk Kwon; Hyeong-Bin Cheong

2010-04-01T23:59:59.000Z

309

E-Print Network 3.0 - antiferromagnetic quantum critical Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

Florida State University Collection: Chemistry 40 Quantum simulation of frustrated Ising spins with trapped ions Summary: LETTERS Quantum simulation of frustrated Ising spins...

310

Methods of classical mechanics applied to turbulence stresses in a tip leakage vortex  

SciTech Connect

Moore et al. measured the six Reynolds stresses in a tip leakage vortex in a linear turbine cascade. Stress tensor analysis, as used in classical mechanics, has been applied to the measured turbulence stress tensors. Principal directions and principal normal stresses are found. A solid surface model, or three-dimensional glyph, for the Reynolds stress tensor is proposed and used to view the stresses throughout the tip leakage vortex. Modeled Reynolds stresses using the Boussinesq approximation are obtained from the measured mean velocity strain rate tensor. The comparison of the principal directions and the three-dimensional graphic representations of the strain and Reynolds stress tensors aids in the understanding of the turbulence and what is required to model it.

Moore, J.G.; Schorn, S.A.; Moore, J. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)

1996-10-01T23:59:59.000Z

311

A model for vortex-induced vibration analysis of long-span bridges  

Science Journals Connector (OSTI)

Abstract Long-span structures are susceptible to wind-induced vibrations due to their low oscillation frequency and low mechanical damping. Although many efforts have been made in the past to model vortex-induced vibration of circular cylinders, limited studies can be found for non-circular cross sections representative of long-span bridge decks. A model for vortex-induced vibration analysis of long-span bridge is presented in this paper. The aeroelastic equation of motion of the model, a procedure to extract aeroelastic coefficients from wind tunnel experiments, analysis of full-scale structures incorporating loss of spanwise correlation of aeroelastic forces, and comparison between simulated and full-scale measured responses on a twin deck bridge (Fred Hartman bridge, Baytown, Texas) are discussed. Six bluff sections – Deer Isle bridge, Tsurumi bridge, Fred Hartman bridge, generic rectangular, H shaped, and circular models – were considered in this research program.

Mehedy Mashnad; Nicholas P. Jones

2014-01-01T23:59:59.000Z

312

Amplitude distribution of magnetoelastic waves propagating in a vortex field in a superconducting layer  

Science Journals Connector (OSTI)

Magnetic field enters the type ? II superconducting body along a discrete arrangement of magnetic vortex lines. In the dynamic case when the magnetic field vary in time around each such a line a supercurrent flows. So the vorticesinteract one to another with the help of the Lorentz force forming this way a new mechanical field of elastic properties. Moreover those lines arrange themselves in a triangular or quadratic lattice. Such a set is observed if the intensity of the applied to the materialmagnetic field is close to its lower limiting value. The paper aims at investigating amplitude distributions of magnetoelastic waves propagating solely in the vortex field of the superconducting layer. Our attention have been focused on the applied magnetic field intensity influence on those amplitudes for various wave frequencies.

Bogdan T. Maruszewski; Andrzej Drzewiecki; Roman Starosta

2008-01-01T23:59:59.000Z

313

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

E-Print Network (OSTI)

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...

Supak, Kevin Robert

2008-10-10T23:59:59.000Z

314

Effects of syngas composition on combustion induced vortex breakdown (CIVB) flashback in a swirl stabilized combustor  

Science Journals Connector (OSTI)

Flame flashback attributed to combustion induced vortex breakdown (CIVB) is a major design challenge for swirl stabilized burner combustors. This paper presents an experimental investigation of combustion induced vortex breakdown (CIVB) flashback propensity for flames yielded from Hydrogen (H2)–Carbon Monoxide (CO) fuel blends and actual synthesized gas (syngas) mixtures. A two-fold experimental approach, consisting of a high definition digital imaging system and a high speed PIV system, was employed. The main emphasis was on the effect of concentration of different constituents in fuel mixtures on flashback limit. In addition, the effect of Swirl Number on flashback propensity was discussed. The percentage of H2 in fuel mixtures played the dominant role when CIVB flashback occurred. For a given air mass flow rate, the mixture containing a higher percentage of H2 underwent flashback at much leaner conditions. Flashback maps for actual syngas fuel compositions showed a distinct behavior when various concentrations of diluents were introduced in the mixture. For the two major diluents tested, carbon dioxide (CO2) and nitrogen dioxide (NO2), CO2 was more dominant. The effect of Swirl Number on the flashback propensity was also tested and showed a decrease with an increase in Swirl Number. The final portion of this paper also provides an analysis of flow field of reacting flames which revealed complex vortex–chemistry interactions leading to vortex breakdown and flashback. Based on the experimental results a parametric model similar to Peclet Number approach was developed employing a flame quenching concept. A value of the quench parameter, Cquench was obtained from the correlation of flow Peclet Number and flame Peclet Number, which was observed to be dominated by the fuel composition rather than Swirl Number.

Bidhan Dam; Gilberto Corona; Mir Hayder; Ahsan Choudhuri

2011-01-01T23:59:59.000Z

315

Aircraft Emissions Deposited in the Stratosphere and Within the Arctic Polar Vortex. Final report  

SciTech Connect

This report describes an analysis of the quantity of emissions (water vapor, NO(x)) projected to be deposited directly within the Arctic polar vortex by projected fleets of Mach 2.4 high speed civil transports (HSCT`s). It also evaluates the amount of emissions from subsonic aircraft which are emitted into the lower stratosphere using aircraft emission inventories developed earlier for May 1990 as representative of the annual average.

Baughcum, S.L.

1996-04-01T23:59:59.000Z

316

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

SciTech Connect

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.

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

317

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

SciTech Connect

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.

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

318

Phase diagram of the frustrated spin-1/2 Heisenberg antiferromagnet in 2 dimensions  

Science Journals Connector (OSTI)

Using a Lanczos technique we study the frustrated spin-(1/2 Heisenberg model on square lattices of 16 and 20 sites. Frustration is introduced by an interaction along the diagonals of the plaquettes with coupling J2?0. For large J2 we found that the ground state breaks (spontaneously) the lattice rotational symmetry. For intermediate values of J2, the squares of order parameters associated with spin-Peierls and ‘‘twisted’’ states have a peak while a similar quantity for a chiral state shows no interesting structure.

Elbio Dagotto and Adriana Moreo

1989-11-06T23:59:59.000Z

319

Single beam optical vortex tweezers with tunable orbital angular momentum  

SciTech Connect

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.

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

320

Anisotropic superconductivity and vortex dynamics in magnetially coupled F/S and F/S/F hybrids.  

SciTech Connect

Magnetically coupled superconductor-ferromagnet hybrids offer advanced routes for nanoscale control of superconductivity. Magnetotransport characteristics and scanning tunneling microscopy images of vortex structures in superconductor-ferromagnet hybrids reveal rich superconducting phase diagrams. Focusing on a particular combination of a ferromagnet with a well-ordered periodic magnetic domain structure with alternating out-of-plane component of magnetization, and a small coherence length superconductor, we find directed nucleation of superconductivity above the domain wall boundaries. We show that near the superconductor-normal state phase boundary the superconductivity is localized in narrow mesoscopic channels. In order to explore the Abrikosov flux line ordering in F/S hybrids, we use a combination of scanning tunneling microscopy and Ginzburg-Landau simulations. The magnetic stripe domain structure induces periodic local magnetic induction in the superconductor, creating a series of pinning-anti-pinning channels for externally added magnetic flux quanta. Such laterally confined Abrikosov vortices form quasi-1D arrays (chains). The transitions between multichain states occur through propagation of kinks at the intermediate fields. At high fields we show that the system becomes nonlinear due to a change in both the number of vortices and the confining potential. In F/S/F hybrids we demonstrate the evolution of the anisotropic conductivity in the superconductor that is magnetically coupled with two adjacent ferromagnetic layers. Stripe magnetic domain structures in both F-layers are aligned under each other, resulting in a directional superconducting order parameter in the superconducting layer. The conductance anisotropy strongly depends on the period of the magnetic domains and the strength of the local magnetization. The anisotropic conductivity of up to three orders of magnitude can be achieved with a spatial critical temperature modulation of 5% of T{sub c}. Induced anisotropic properties in the F/S and F/S/F hybrids have a potential for future application in switching and nonvolatile memory elements operating at low temperatures.

Karapetrov, G.; Belkin, A.; Iavarone, M.; Fedor, J.; Novosad, V.; Milosevic, M. V.; Peeters, F. M. (Materials Science Division); (Illinois Inst. of Tech.); (Temple Univ.); (Slovak Academy of Sciences); (Univ. Antwerpen)

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

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

SciTech Connect

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.

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

322

Turbine blade platform film cooling with simulated stator-rotor purge flow with varied seal width and upstream wake with vortex  

E-Print Network (OSTI)

phase locations to model the unsteady wake formed at the trailing edge of the upstream vane. Delta wings were also placed in four positions to create a vortex similar to the passage vortex at the exit of the vane. The film cooling effectiveness...

Blake, Sarah Anne

2009-05-15T23:59:59.000Z

323

WAVE-VORTEX MODE COUPLING IN ASTROPHYSICAL ACCRETION DISKS UNDER COMBINED RADIAL AND VERTICAL STRATIFICATION  

SciTech Connect

We examine accretion disk flow under combined radial and vertical stratification utilizing a local Cartesian (or ''shearing box'') approximation. We investigate both axisymmetric and nonaxisymmetric disturbances with the Boussinesq approximation. Under axisymmetric disturbances, a new dispersion relation is derived. It reduces to the Solberg-Hoieland criterion in the case without vertical stratification. It shows that, asymptotically, stable radial and vertical stratification cannot induce any linear instability; Keplerian flow is accordingly stable. Previous investigations strongly suggest that the so-called bypass concept of turbulence (i.e., that fine-tuned disturbances of any inviscid smooth shear flow can reach arbitrarily large transient growth) can also be applied to Keplerian disks. We present an analysis of this process for three-dimensional plane-wave disturbances comoving with the shear flow of a general rotating shear flow under combined stable radial and vertical rotation. We demonstrate that large transient growth occurs for K{sub 2}/k{sub 1} >> 1 and k{sub 3} = 0 or k{sub 1} {approx} k{sub 3}, where k{sub 1}, K{sub 2}, and k{sub 3} are the azimuthal, radial, and vertical components of the initial wave vector, respectively. By using a generalized ''wave-vortex'' decomposition of the disturbance, we show that the large transient energy growth in a Keplerian disk is mainly generated by the transient dynamics of the vortex mode. The analysis of the power spectrum of total (kinetic+potential) energy in the azimuthal or vertical directions shows that the contribution coming from the vortex mode is dominant at large scales, while the contribution coming from the wave mode is important at small scales. These findings may be confirmed by appropriate numerical simulations in the high Reynolds number regime.

Salhi, A. [Departement de Physique, Faculte des Sciences de Tunis, 1060 Tunis (Tunisia); Lehner, T. [LUTH, UMR 8102 CNRS, Observatoire de Paris-Meudon, 5 place de Janssen, F-92195 Meudon (France); Godeferd, F.; Cambon, C. [Laboratoire de Mecanique des Fluides et d'Acoustique, Ecole Centrale de Lyon, Universite de Lyon, UMR 5509, CNRS, INSA, UCB, F-69134 Ecully Cedex (France)

2013-07-10T23:59:59.000Z

324

Reconnection in orthogonally interacting vortex tubes: Direct numerical simulations and quantifications  

Science Journals Connector (OSTI)

The three?dimensional time evolution of two orthogonally offset cylindrical vortices of equal strength is simulated by solving the hyperviscosity?regularized incompressible Navier–Stokes equations. A Fourier pseudospectral method with a time?split integration scheme is used for the solution. Four runs with different Reynolds numbers ranging between 690–2100 are performed each with a resolution of 963 collocation points. The sequence of important physical processes and the evolution of local and global quantities such as vorticity velocity and mean?square strain rate are presented. It is found that the growth rate of the maximum vorticity is at most exponential. The Reynolds number dependence of the time scale of reconnection the vorticity growth rate and the time at which the maximum vorticity is attained are examined and differences between the present results and Saffman’s essentially two?dimensional model predictions are encountered and elucidated. The distributions of the eigenvalues ? ? ? and the corresponding eigenvectors s ? s ? s ? of the rate of strain tensor S i j are calculated at different times. It is found that as the mean?square strain rate ? increases during the evolution s ? and the vorticity vector ? are perfectly aligned and ?>0 in high ? regions. Strong temporal spatial and Reynolds number dependence of the strain fields is also seen. Evidence is presented that during reconnection the vorticity growth in newly forming bridges takes place in the vicinity of the upper stagnation line segment of the vortex dipole due to the nature of the vortex stretching term. Also examined is the initial finger formation and it is found that the initial nonuniform axial stretching and the displacement of the vortex cores due to a lift force play an important role in this process.

O. N. Boratav; R. B. Pelz; N. J. Zabusky

1992-01-01T23:59:59.000Z

325

Magnetostructural correlations in the antiferromagnetic Co2?x Cux(OH)AsO4 (x=0 and 0.3) phases  

Science Journals Connector (OSTI)

The Co2?xCux(OH)AsO4 (x=0 and 0.3) compounds have been synthesized under mild hydrothermal conditions and characterized by X-ray single-crystal diffraction and spectroscopic data. The hydroxi-arsenate phases crystallize in the Pnnm orthorhombic space group with Z=4 and the unit-cell parameters are a=8.277(2) Å, b=8.559(2) Å, c=6.039(1) Å and a=8.316(1) Å, b=8.523(2) Å, c=6.047(1) Å for x=0 and 0.3, respectively. The crystal structure consists of a three-dimensional framework in which M(1)O5-trigonal bipyramid dimers and M(2)O6-octahedral chains (M=Co and Cu) are present. Co2(OH)AsO4 shows an anomalous three-dimensional antiferromagnetic ordering influenced by the magnetic field below 21 K within the presence of a ferromagnetic component below the ordering temperature. When Co2+ is partially substituted by Cu2+ions, Co1.7Cu0.3(OH)AsO4, the ferromagnetic component observed in Co2(OH)AsO4 disappears and the antiferromagnetic order is maintained in the entire temperature range. Heat capacity measurements show an unusual magnetic field dependence of the antiferromagnetic transitions. This ?-type anomaly associated to the three-dimensional antiferromagnetic ordering grows with the magnetic field and becomes better defined as observed in the non-substituted phase. These results are attributed to the presence of the unpaired electron in the dx2?y2 orbital and the absence of overlap between neighbour ions.

I. de Pedro; J.M. Rojo; J.L. Pizarro; J. Rodríguez Fernández; M.I. Arriortua; T. Rojo

2011-01-01T23:59:59.000Z

326

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

E-Print Network (OSTI)

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.

V. M. Kaurov; A. B. Kuklov

2004-06-15T23:59:59.000Z

327

Optical excitation of quasiparticle pairs in the vortex core of high- T sub c superconductors  

SciTech Connect

A far-infrared resonance has been observed in superconducting YBa{sub 2}Cu{sub 3}O{sub 7} thin films in the presence of high magnetic fields. It corresponds to the quasiparticle pair creation process inside the vortex core. The resonance frequency is {omega}{sub 0}=1.3{ital kT}{sub {ital c}}/{h bar} with a linewidth 1/{tau}{congruent}0.6{omega}. This value for {omega}{sub 0} implies, within BCS theory, a large energy gap in YBa{sub 2}Cu{sub 3}O{sub 7}.

Karraie, K.; Choi, E.J.; Dunmore, F.; Liu, S.H.; Drew, H.D. (Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742 (United States) Laboratory for Physical Sciences, College Park, Maryland 20740 (United States)); Li, Q.; Fenner, D.B. (Advanced Fuel Research, E. Hartford, Connecticut 06138 (United States)); Zhu, Y.D.; Zhang, F. (Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221 (United States))

1992-07-06T23:59:59.000Z

328

Static vacancies on a 2D Heisenberg spin-1/2 antiferromagnet  

Science Journals Connector (OSTI)

We study static vacancies on a 2D Heisenberg spin-(1/2 lattice at T=0, using linear spin-wave theory (LSW) and exact diagonalizaton. Unexpectedly, quantum fluctuations are reduced on neighbors of an isolated vacancy. Two vacancies are attractive, with lowest energy as nearest neighbors. We find LSW to be surprisingly accurate relative to exact diagonalization, both done on a 4×4 lattice. However, LSW on larger systems gives substantial modification of the 4×4 results for binding and ground-state energies, suggesting the need for larger lattices than previously suspected for reliable numerical estimates.

N. Bulut; D. Hone; D. J. Scalapino; E. Y. Loh

1989-05-01T23:59:59.000Z

329

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

SciTech Connect

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.

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

330

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

E-Print Network (OSTI)

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 $\\theta_W=\\frac{\\pi}{4}$.

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

2014-08-20T23:59:59.000Z

331

Theory of hybrid state in a metal with a small Fermi surface and strong collective excitations  

Science Journals Connector (OSTI)

We develop a theory of a hybrid state, where quasiparticles coexist with strong collective modes, taking as a starting point a model of infinitely many one-dimensional Mott insulators weakly coupled by interchain tunneling. This state exists at an intermediate temperature range and undergoes an antiferromagnetic phase transition at temperatures much smaller than the Mott-Hubbard gap. The most peculiar feature of the hybrid state is that its Fermi surface volume is unrelated to the electron density. We present a self-consistent derivation of the low-energy effective action for our model.

F. H. L. Essler and A. M. Tsvelik

2005-05-26T23:59:59.000Z

332

Origin State Destination State  

U.S. Energy Information Administration (EIA) Indexed Site

6. Estimated rail transportation rates for coal, state to state, STB data 6. Estimated rail transportation rates for coal, state to state, STB data Origin State Destination State 2001 2002 2003 2004 2005 2006 2007 2008 2009 2001-2009 2008-2009 Alabama Alabama W W W W W W W W W W W Alabama Georgia W W W W W W W W W W W Alabama Illinois - - - - - W W W W - W Colorado Alabama - W W W W W W W W - W Colorado Arizona W W W W W W W W W W W Colorado Arkansas - - - - W W W W - - -

333

Origin State Destination State  

U.S. Energy Information Administration (EIA) Indexed Site

5. Estimated barge transportation rates for coal, state to state, EIA data 5. Estimated barge transportation rates for coal, state to state, EIA data Origin State Destination State 2008 2009 2010 2008-2010 2009-2010 Alabama Alabama $4.31 $4.36 $5.01 7.9 15.0 Alabama Ohio W - - - - Colorado Alabama W - - - - Colorado Florida $11.08 $12.65 $13.27 9.4 4.9 Colorado Indiana $6.29 W - - - Colorado Iowa W - - - - Colorado Kentucky W - - - - Colorado Mississippi - - W - - Colorado Ohio - W - - - Colorado Tennessee W - - - - Illinois Alabama W $13.15 $14.28 W 8.6

334

Origin State Destination State  

U.S. Energy Information Administration (EIA) Indexed Site

8. Estimated truck transportation rates for coal, state to state, EIA data 8. 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 Georgia - - W - - Alabama Indiana W W - - - Colorado Colorado W W W W W Colorado Michigan - - W - - Illinois Florida W - - - - Illinois Illinois $7.51 $4.74 $3.37 -33.0 -28.8 Illinois Indiana W W - - - Illinois Minnesota W W - - - Illinois Missouri $21.73 $20.23 $13.30 -21.8 -34.3 Indiana Alabama - W - - -

335

Origin State Destination State  

U.S. Energy Information Administration (EIA) Indexed Site

5. Estimated rail transportation rates for coal, state to state, STB data 5. Estimated rail transportation rates for coal, state to state, STB data Origin State Destination State 2001 2002 2003 2004 2005 2006 2007 2008 2009 2001-2009 2008-2009 Alabama Alabama W W W W W W W W W W W Alabama Georgia W W W W W W W W W W W Alabama Illinois - - - - - W W W W - W Colorado Alabama - W W W W W W W W - W Colorado Arizona W W W W W W W W W W W Colorado Arkansas - - - - W W W W - - -

336

Origin State Destination State  

U.S. Energy Information Administration (EIA) Indexed Site

4. Estimated rail transportation rates for coal, state to state, STB data 4. Estimated rail transportation rates for coal, state to state, STB data Origin State Destination State 2001 2002 2003 2004 2005 2006 2007 2008 2009 2001-2009 2008-2009 Alabama Alabama W W W W W W W W W W W Alabama Georgia W W W W W W W W W W W Alabama Illinois - - - - - W W W W - W Colorado Alabama - W W W W W W W W - W Colorado Arizona W W W W W W W W W W W Colorado Arkansas - - - - W W W W - - -

337

Origin State Destination State  

U.S. Energy Information Administration (EIA) Indexed Site

6. Estimated barge transportation rates for coal, state to state, EIA data 6. Estimated barge transportation rates for coal, state to state, EIA data Origin State Destination State 2008 2009 2010 2008-2010 2009-2010 Alabama Alabama $3.97 $3.97 $4.52 6.7 13.7 Alabama Ohio W - - - - Colorado Alabama W - - - - Colorado Florida $10.21 $11.53 $11.95 8.2 3.7 Colorado Indiana $5.79 W - - - Colorado Iowa W - - - - Colorado Kentucky W - - - - Colorado Mississippi - - W - - Colorado Ohio - W - - - Colorado Tennessee W - - - - Illinois Alabama W $11.99 $12.87 W 7.3

338

Origin State Destination State  

U.S. Energy Information Administration (EIA) Indexed Site

7. Estimated truck transportation rates for coal, state to state, EIA data 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 Georgia - - W - - Alabama Indiana W W - - - Colorado Colorado W W W W W Colorado Michigan - - W - - Illinois Florida W - - - - Illinois Illinois $8.16 $5.20 $3.75 -32.2 -27.9 Illinois Indiana W W - - - Illinois Minnesota W W - - - Illinois Missouri $23.60 $22.20 $14.77 -20.9 -33.5 Indiana Alabama - W - - -

339

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

E-Print Network (OSTI)

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

Wallraff, Andreas

340

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

E-Print Network (OSTI)

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

Steinbock, Oliver

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

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

E-Print Network (OSTI)

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.

Robert A. Van Gorder

2014-11-19T23:59:59.000Z

342

Energy Losses Due to Vortex Shedding from the Lower Edge of a Vertical Plate Attacked by Surface Waves  

Science Journals Connector (OSTI)

...Vertical Plate Attacked by Surface Waves M. Stiassnie E. Naheer Irina Boguslavsky...The ratio between the flux of the energy taken out by the vortex generation process , and the incoming wave energy flux , is shown to be given by where...

1984-01-01T23:59:59.000Z

343

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)

not affect their vertical or lateral positioning. The vortex probe assembly is shown in Figure 2. A comparison of the free-stream velocities obtained from the vortex probe assembly and a standard pitot-static tube revealed a difference of less than one...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...

Van Dusen, Maurice Verne

2012-06-07T23:59:59.000Z

344

Effects of atmospheric conditions and control surface deflections on vortex characteristics  

E-Print Network (OSTI)

I I I i. C iS OF:"-:, ','". : iFII! 2! C CO", Df if Of!S f'-, 'ID CO, ", IROI ':L'll ', CI DI. I I ECT IOIIS O', I 'ilORT:-X ' I~OR;. C I L!If ISTICS 0 Thesis by CALVfl'I L!O'. , 'PRD SIIEIIKIR, JR. Subr~i fis!i to the G! ', 'uete Col ieije...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...

Shenkir, Calvin Edward

2012-06-07T23:59:59.000Z

345

Mechanical (acoustic?like) wave propagation along a vortex array in the superconducting heterostructure  

Science Journals Connector (OSTI)

Magnetic flux can penetrate the type ? II superconductor in the form of Abrikosov vortices (also called flux lines flux tubes or fluxons) each carrying a quantum of magnetic flux. These tiny vortices of supercurrent tend to arrange themselves in a triangular or quadratic flux?line lattice. Since the vortices are formed by the applied magnetic field around of each of them the supercurrent flows. Moreover there also exist some Lorentz force interactions among them. Those interactions form an origin of an additional mechanical (stress) field occurring in the type?II superconductor. The paper deals with an analysis of elastic (acoustic?like) wave propagation solely along vortices in a heterostructure consisted of the superconducting layer put on the superconducting substrate. Dispersion and the amplitude distribution of those waves in the vortex field existing in that structure has been presented.

Bogdan T. Maruszewski; Andrzej Drzewiecki; Roman Starosta

2008-01-01T23:59:59.000Z

346

Plasma resonance at low magnetic fields as a probe of vortex line meandering in layered superconductors  

Science Journals Connector (OSTI)

We consider the magnetic-field dependence of the plasma resonance frequency in pristine and in irradiated Bi2Sr2CaCu2O8 crystals near Tc. At low magnetic fields we relate linear in field corrections to the plasma frequency to the average distance between the pancake vortices in the neighboring layers (wandering length). We calculate the wandering length in the case of thermal wiggling of vortex lines, taking into account both Josephson and magnetic interlayer coupling of pancakes. Analyzing experimental data, we found that (i) the wandering length becomes comparable with the London penetration depth near Tc and (ii) at small melting fields (line liquid phase in this field range. We also found that pinning by columnar defects affects weakly the field dependence of the plasma resonance frequency near Tc.

L. N. Bulaevskii; A. E. Koshelev; V. M. Vinokur; M. P. Maley

2000-02-01T23:59:59.000Z

347

Plasma resonance at low magnetic fields as a probe of vortex line meandering in layered superconductors  

E-Print Network (OSTI)

We consider the magnetic field dependence of the plasma resonance frequency in pristine and in irradiated Bi$_2$Sr$_2$CaCu$_2$O$_8$ crystals near $T_c$. At low magnetic fields we relate linear in field corrections to the plasma frequency to the average distance between the pancake vortices in the neighboring layers (wandering length). We calculate the wandering length in the case of thermal wiggling of vortex lines, taking into account both Josephson and magnetic interlayer coupling of pancakes. Analyzing experimental data, we found that (i) the wandering length becomes comparable with the London penetration depth near T$_{c}$ and (ii) at small melting fields ($line liquid phase in this field range. We also found that pinning by columnar defects affects weakly the field dependence of the plasma resonance frequency near $T_c$.

L. N. Bulaevskii; A. E. Koshelev; V. M. Vinokur; M. P. Maley

1999-07-29T23:59:59.000Z

348

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

SciTech Connect

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.

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

349

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

SciTech Connect

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.

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

350

Coexistence of bulk superconducting and antiferromagnetic order in the spin-ladder system Sr2Ca12Cu24O41  

Science Journals Connector (OSTI)

Combined ac-susceptibility and ac-calorimetry measurements under hydrostatic pressure on new single crystals of the spin-ladder system Sr14?xCaxCu24O41 (x=12) in good hydrostatic conditions allow us to unambiguously establish the phase diagram. We show that bulk superconductivity and antiferromagnetic order coexist over a wide pressure range, which is quite rare in strongly correlated systems where the same electrons participate in superconductivity and magnetic order. We suggest that this is possible by the special microscopic structure of this material, containing ladders and chains, with a weak coupling between the two.

S. Vanishri; D. Braithwaite; B. Salce; C. Marin; J. Flouquet

2010-03-10T23:59:59.000Z

351

Origin State Destination State  

U.S. Energy Information Administration (EIA) Indexed Site

8. Estimated rail transportation rates for coal, state to state, EIA data 8. Estimated rail transportation rates for coal, state to state, EIA data Origin State Destination State 2008 2009 2010 2008-2010 2009-2010 Alabama Alabama $13.29 $12.39 $13.93 2.4 12.5 Alabama Georgia $17.62 $17.84 $20.09 6.8 12.6 Alabama Kentucky - W - - - Alabama New Jersey W - - - - Alabama Pennsylvania - W - - - Arizona Arizona W W W W W Colorado Alabama $31.79 $27.66 $24.93 -11.5 -9.9 Colorado Arizona $25.97 W - - - Colorado Arkansas W - - - - Colorado California - $34.20 $46.22 - 35.1 Colorado Colorado $13.04 $7.72 $8.13 -21.1 5.3

352

Origin State Destination State  

U.S. Energy Information Administration (EIA) Indexed Site

Estimated rail transportation rates for coal, state to state, EIA data Estimated rail transportation rates for coal, state to state, EIA data Origin State Destination State 2008 2009 2010 2008-2010 2009-2010 Alabama Alabama $14.43 $13.59 $15.46 3.5 13.8 Alabama Georgia $19.13 $19.58 $22.30 8.0 13.9 Alabama Kentucky - W - - - Alabama New Jersey W - - - - Alabama Pennsylvania - W - - - Arizona Arizona W W W W W Colorado Alabama $34.52 $30.35 $27.67 -10.5 -8.8 Colorado Arizona $28.20 W - - - Colorado Arkansas W - - - - Colorado California - $37.53 $51.30 - 36.7 Colorado Colorado $14.16 $8.47 $9.02 -20.2 6.6

353

Large-Eddy Simulation of Stratified Turbulence. Part II: Application of the Stretched-Vortex Model to the Atmospheric Boundary Layer  

Science Journals Connector (OSTI)

The buoyancy-adjusted stretched-vortex subgrid-scale (SGS) model is assessed for a number of large-eddy simulations (LESs) corresponding to diverse atmospheric boundary layer conditions. The cases considered are free convection, a moderately ...

Georgios Matheou; Daniel Chung

2014-12-01T23:59:59.000Z

354

205Tl NMR observation of vortex lattice formation in the high temperature superconductor Tl2Ba2CuO6  

Science Journals Connector (OSTI)

We report on the asymmetric field distribution of the triangular vortex lattice in the superconductor Tl2Ba2CuO6 as observed by205Tl NMR atB a =4.26 T. A penetra...

M. Mehring; F. Hentsch; Hj. Mattausch…

1989-01-01T23:59:59.000Z

355

Satellite Data Assimilation in Numerical Weather Prediction Models. Part II: Uses of Rain-Affected Radiances from Microwave Observations for Hurricane Vortex Analysis  

Science Journals Connector (OSTI)

A hybrid variational scheme (HVAR) is developed to produce the vortex analysis associated with tropical storms. This scheme allows for direct assimilation of rain-affected radiances from satellite microwave instruments. In the HVAR, the ...

Fuzhong Weng; Tong Zhu; Banghua Yan

2007-11-01T23:59:59.000Z

356

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)

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...

Kelley, Edward Madison

2012-06-07T23:59:59.000Z

357

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)

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

Mohseni, Kamran

358

Neutron scattering study of two-magnon states in the quantum magnet copper nitrate  

Science Journals Connector (OSTI)

We report measurements of the two-magnon states in a dimerized antiferromagnetic chain material, copper nitrate [Cu(NO3)2?2.5D2O]. Using inelastic neutron scattering we have measured the one- and two-magnon excitation spectra in a large single crystal. The data are in excellent agreement with a perturbative expansion of the alternating Heisenberg Hamiltonian from the strongly dimerized limit. The expansion predicts a two-magnon bound state for q?(2n+1)?d which is consistent with the neutron scattering data.

D. A. Tennant; C. Broholm; D. H. Reich; S. E. Nagler; G. E. Granroth; T. Barnes; K. Damle; G. Xu; Y. Chen; B. C. Sales

2003-02-27T23:59:59.000Z

359

Heisenberg Spin Bus as a Robust Transmission Line for Perfect State Transfer  

E-Print Network (OSTI)

We study the protocol known as quantum state transfer for a strongly coupled antiferromagnetic spin chain or ring (acting as a spin bus), with weakly coupled external qubits. By treating the weak coupling as a perturbation, we find that perfect state transfer (PST) is possible when second order terms are included in the expansion. We also show that PST is robust against variations in the couplings along the spin bus and between the bus and the qubits. As evidence of the quantum interference which mediates PST, we show that the optimal time for PST can be smaller with larger qubit separations, for an even-size chain or ring.

Sangchul Oh; Lian-Ao Wu; Yun-Pil Shim; Mark Friesen; Xuedong Hu

2011-02-03T23:59:59.000Z

360

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

SciTech Connect

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.

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

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
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361

Experimental and thermodynamical analyses of the diesel exhaust vortex generator heat exchanger for optimizing its operating condition  

Science Journals Connector (OSTI)

Abstract In this research, a vortex generator heat exchanger is used to recover exergy from the exhaust of an OM314 diesel engine. Twenty vortex generators with 30° angle of attack are used to increase the heat recovery as well as the low back pressure in the exhaust. The experiments are prepared for five engine loads (0, 20, 40, 60 and 80% of full load), two exhaust gases amount (50 and 100%) and four water mass flow rates (50, 40, 30 and 20 g/s). After a thermodynamical analysis on the obtained data, an optimization study based on Central Composite Design (CCD) is performed due to complex effect of engine loads and water mass flow rates on exergy recovery and irreversibility to reach the best operating condition.

M. Hatami; D.D. Ganji; M. Gorji-Bandpy

2015-01-01T23:59:59.000Z

362

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

SciTech Connect

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.

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

363

Vortex graphs as N-omers and CP(N-1) Skyrmions in N-component Bose-Einstein condensates  

E-Print Network (OSTI)

Stable vortex N-omers are constructed in coherently coupled N-component Bose-Einstein condensates. We classify all possible N-omers in terms of the mathematical graph theory and numerically construct all graphs for N=2,3,4. We also find that N-omers are well described as CP(N-1) skyrmions when inter-component and intra-component couplings are U(N) symmetric, and we evaluate their size dependence on the Rabi coupling.

Minoru Eto; Muneto Nitta

2013-03-25T23:59:59.000Z

364

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

SciTech Connect

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.

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

365

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

SciTech Connect

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)

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

366

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

SciTech Connect

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.

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

367

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

E-Print Network (OSTI)

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, ...

Helton, Joel Strader

2009-01-01T23:59:59.000Z

368

Effects of vortex generators on a blunt trailing-edge airfoil for wind turbines  

Science Journals Connector (OSTI)

Abstract Vortex generators (VGs) are commonly-used effective flow separation control devices, and are proved to have potential to improve the aerodynamic performance of large wind turbines. In this paper, the flow physics of \\{VGs\\} and how their size affects the aerodynamic performance of a blunt trailing-edge airfoil DU97-W-300 have been investigated using CFD simulations. Based on wind turbine dedicated airfoil with and without \\{VGs\\} respectively, three-dimensional numerical models were established and further validated through the comparisons between the numerical results and the experimental data. The effects of VGs' size were analyzed from several perspectives, such as trailing-edge height, length, short and long spacing between an adjacent pair of VGs. The results indicate that drag penalty is more sensitive to the increase of VG height than lift; an increment of VG length leads to negative effects on both lift and drag; increases of the spacing between an adjacent pair of \\{VGs\\} have positive impact on suppression of separated flow. Additionally, the flow field characteristics were further revealed by the analysis of streamlines and vortices in the wake region.

Linyue Gao; Hui Zhang; Yongqian Liu; Shuang Han

2015-01-01T23:59:59.000Z

369

Engineering Nanocolumnar Defect Configurations for Optimized Vortex Pinning in High Temperature Superconducting Nanocomposite Wires  

SciTech Connect

High temperature superconducting (HTS), coated conductor wires based on nanocomposite films containing self-assembled, insulating BaZrO3 (BZO) nanocolumnar defects have previously been reported to exhibit enhanced vortex pinning. Here, we report on microstructural design via control of BZO nanocolumns density in YBa2Cu3O7- (YBCO)+BZO nancomposite films to achieve the highest critical current density, Jc(H, ,T). X-ray diffraction and microstructural examination shows increasing number density of epitaxial BZO nanocolumns in the highly cube-textured YBCO matrix with increasing nominal BZO additions. Transport property measurement reveals that an increase in BZO content upto 4 vol% is required to sustain the highest pinning and Jc performance as the magnetic field increases. By growing thicker, single-layer nanocomposite films (~4 m) with controlled density of BZO columnar defects, the critical current (Ic) of ~1000 A/cm at 77 K, self-field and the minimum Ic of 455 A/cm at 65 K and 3 T for all magnetic field orientations were obtained. This is the highest Ic reported to date for films on metallic templates which are the basis for the 2nd generation, coated conductor-based HTS wires.

Wee, Sung Hun [ORNL; Zuev, Yuri L [ORNL; Cantoni, Claudia [ORNL; Goyal, Amit [ORNL; Ahuja, Raj [Waukesha Electric Systems Inc.; Abiade, J. [North Carolina A& T State University

2013-01-01T23:59:59.000Z

370

On the efficiency of energy harvesting using vortex-induced vibrations of cables  

Science Journals Connector (OSTI)

Abstract Many technologies based on fluid–structure interaction mechanisms are being developed to harvest energy from geophysical flows. The velocity of such flows is low, and so is their energy density. Large systems are therefore required to extract a significant amount of energy. The question of the efficiency of energy harvesting using vortex-induced vibrations (VIV) of cables is addressed in this paper, through two reference configurations: (i) a long tensioned cable with periodically-distributed harvesters and (ii) a hanging cable with a single harvester at its upper extremity. After validation against either direct numerical simulations or experiments, an appropriate reduced-order wake-oscillator model is used to perform parametric studies of the impact of the harvesting parameters on the efficiency. For both configurations, an optimal set of parameters is identified and it is shown that the maximum efficiency is close to the value reached with an elastically-mounted rigid cylinder. The variability of the efficiency is studied in light of the fundamental properties of each configuration, i.e. body flexibility and gravity-induced spatial variation of the tension. In the periodically-distributed harvester configuration, it is found that the standing-wave nature of the vibration and structural mode selection plays a central role in energy extraction. In contrast, the efficiency of the hanging cable is essentially driven by the occurrence of traveling wave vibrations.

Clément Grouthier; Sébastien Michelin; Rémi Bourguet; Yahya Modarres-Sadeghi; Emmanuel de Langre

2014-01-01T23:59:59.000Z

371

Development of a free vortex wake method code for offshore floating wind turbines  

Science Journals Connector (OSTI)

Offshore floating wind turbines (OFWTs) present unique aerodynamic analysis challenges. Motion–derived velocity perturbations in the wake necessitate higher–fidelity aerodynamic analysis methods than the ubiquitous momentum balance techniques currently in use. A more physically–sound approach is to model the wake generated by a wind turbine rotor as a freely convecting lattice, using the resultant inflow to estimate rotor loads, as it done with a free vortex wake method (FVM). The FVM code Wake Induced Dynamics Simulator (WInDS) was developed at the University of Massachusetts at Amherst to predict the aerodynamic loading and wake evolution of an OFWT to a higher degree of accuracy than is possible via momentum balance methods. A series of validation cases were conducted to provide some basis for applying \\{WInDS\\} to floating wind turbine cases, for which no aerodynamic experimental data is currently available. The results from these tests show that \\{WInDS\\} is able to accurately predict the aerodynamically–derived loads and wake structures generated by various fixed and rotary–wing cases, and may therefore be applied to more complex cases, like OFWTs, with a degree of confidence.

T. Sebastian; M.A. Lackner

2012-01-01T23:59:59.000Z

372

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)

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

Eggert, Sebastian

373

Effect of antiferromagnetic spin correlations on lattice distortion and charge ordering in Pr0.5Ca1.5MnO4  

SciTech Connect

We use neutron scattering to study the lattice and magnetic structure of the layered half-doped manganite Pr0.5Ca1.5MnO4. On cooling from high temperature, the system first becomes chargeand orbital-ordered (CO/OO) near TCO = 300 K and then develops checkerboard-like antiferromagnetic (AF) order below TN = 130 K. At temperatures above TN but below TCO (TN

Chi, Songxue [ORNL; Ye, Feng [ORNL; Dai, Pengcheng [ORNL; Fernandez-Baca, Jaime A [ORNL; Huang, Q. [National Institute of Standards and Technology (NIST); Lynn, J. W. [National Institute of Standards and Technology (NIST); Plummer, E Ward [ORNL; Mathieu, R. [Spin Superstructure Project, ERATO, Japan Science and Technology, Tsukuba 305-85; Kaneko, Y. [Spin Superstructure Project, ERATO, Japan Science and Technology, Tsukuba 305-85; Tokura, Y. [University of Tokyo, Tokyo, Japan

2007-01-01T23:59:59.000Z

374

Density of states of a semi-infinite rare-earth metal with magnetic structure: A simple model  

Science Journals Connector (OSTI)

Using a simple tight-binding model and the transfer matrix approach, we have calculated the spectral density of states (SDOS) of a rare-earth metal in the presence of a surface for different magnetic arrangements (such as ferromagnetic, antiferromagnetic, and conical orderings). The local density of states (LDOS) has also been calculated for some examples, integrating the SDOS over the Brillouin zone. The main effect observed deals with the absence of Van Hove's singularities in the surface LDOS, a fact that appears to be an intrinsic property of the surface. Finally the relaxation of the overlap parameters at the surface is discussed and some numerical examples are shown.

Bernardo Laks and G. G. Cabrera

1979-09-15T23:59:59.000Z

375

Vortex erosion and amalgamation in a new model of large scale flow on the sphere  

SciTech Connect

The pseudo-spectral methodology that is typically employed to simulate fluid flow in spherical geometry exhibits, among other limitations, a severe degradation of performance at high resolution. Finite element models based upon the application of multigrid methods may be designed so as to avoid this defect while also allowing for greater local control over the computational mesh. We describe herein the details of the mathematical methods that are required to implement such a computational structure and apply these methods to design a model based upon the two dimensional spherical barotropic vorticity equation, the simplest framework within which their viability may be tested. The model is thereafter employed in the analysis of two essentially inviscid nonlinear dynamical problems in order to provide proof of concept. The first of these test problems entails repeating a well known pseudospectral calculation of the erosion of a polar vortex under slow, quasi-steady, Rossby wave forcing at low zonal wavenumber. The second test problem concerns the simulation of the nonlinear development of the instability of a zonal shear band into a train of like signed vortices which subsequently amalgamate through the nonlinear pairing interaction. Results of these test calculations, as well as those based upon additional analyses that we discuss herein, demonstrate that the performance of our initial methodology meets the basic criteria of fluid flow simulation. This suggests, on the basis of theoretical efficiency, that optimized versions could eventually compete with the large production codes which are in operation today. Our future intent is to further develop this computational structure so as to create a new class of three-dimensional general circulation models that may be employed in a wide variety of astrophysical and atmosphere-ocean applications. 25 refs., 11 figs.

Stuhne, G.R.; Peltier, W.R. [Univ. of Toronto, Ontario (Canada)] [Univ. of Toronto, Ontario (Canada)

1996-10-01T23:59:59.000Z

376

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

SciTech Connect

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.

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

2002-08-01T23:59:59.000Z

377

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)

-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

Paris-Sud XI, Université de

378

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

E-Print Network (OSTI)

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.

Søren Gammelmark; Klaus Mølmer

2009-11-25T23:59:59.000Z

379

A viscous vortex single-mode bubble evolution model of Rayleigh-Taylor instability and its numerical study  

Science Journals Connector (OSTI)

This paper has developed a viscous single-mode bubble evolution model of Rayleigh-Taylor instabilities (RTIs), which is an extension of the single-mode potential models of Jacobs and Rikanati. The viscous vortex model explained the viscous effects of its early stage of RTI development for low Atwood number flow. Furthermore, direct numerical simulations of RTI are studied with Navier-Stokes equations and a transport-diffusive equation. Agreement between the theoretical model and the numerical results shows that simulations of these instabilities is feasible using the mathematical miscible fluid model simulating RTI.

Xu Zhang; Jinhong Liu

2013-01-01T23:59:59.000Z

380

Copper oxide superconductors: A distinguishable thermodynamic state  

Science Journals Connector (OSTI)

The temperature dependence of the resistivity and Seebeck coefficient for the two p-type systems La2CuO4+?, 0???0.09, and La2-xSrxCuO4, 0?x?0.3, are reported and interpreted in the context of overall phase diagrams. Above room temperature, the La2CuO4+? system tends to lose oxygen at 1 atm O2; superconductive samples exhibit a first-order loss of oxygen above 500 K to revert to the antiferromagnetic phase. Below a transition temperature Ts?300 K, compositions with 0antiferromagnetic and a superconductive phase; the superconductive phase appears to undergo a further dynamic segregation into hole-rich and hole-poor domains in the interval Tcstate at Tc. The origin of the unusual electron-lattice interactions in the normal state of the superconductive compositions is attributed to a coexistence of ionic and covalent bonding at a transition from more ionic to covalent Cu:3dx2-y2-O:2p? bonding in the CuO2 sheets; through the transition the orbital hybridization and Hubbard U parameter vary sensitively with both the Cu-O bond length and the formal local oxidation state at a Cu atom.

J. B. Goodenough, J.-S. Zhou, and J. Chan

1993-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
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381

Field-Induced Spin-Flop in Antiferromagnetic Semiconductors with Commensurate and Incommensurate Magnetic Structures: Li2FeGeS4 (LIGS) and Li2FeSnS4 (LITS)  

Science Journals Connector (OSTI)

Li2FeGeS4 (LIGS) and Li2FeSnS4 (LITS), which are among the first magnetic semiconductors with the wurtz-kesterite structure, exhibit antiferromagnetism with TN ? 6 and 4 K, respectively. Both compounds undergo a conventional metamagnetic transition that ...Divalent ions are directed to specific locations within the structures of the Li2?Fe?IV?S4 diamond-like materials to generate antiferromagnetic ordering. Both compounds undergo a reversible spin-flop transition. Changing the tetravalent ion in these materials alters the bandgaps and magnetic structures. The indirect-gap (Eg = 1.4 eV) semiconductor Li2FeGeS4 has a magnetic structure that is commensurate with the nuclear structure, while Li2FeSnS4 has a direct bandgap (Eg = 1.9 eV) and an incommensurate magnetic structure.

Jacilynn A. Brant; Clarina dela Cruz; Jinlei Yao; Alexios P. Douvalis; Thomas Bakas; Monica Sorescu; Jennifer A. Aitken

2014-11-14T23:59:59.000Z

382

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

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.

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

383

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

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.

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

384

The Impact of Cold Dark Matter Variants on the Halos of the First Stars and Galaxies: Angular Momentum and Vortex Creation in BEC Dark Matter  

SciTech Connect

If cold dark matter elementary particles form a Bose-Einstein condensate, their superfluidity may distinguish them from other forms of cold dark matter, including the creation of quantum vortices. We have shown that such vortices are favored in strongly-coupled condensates. Vortex creation causes central densities to drop, thus affecting the dynamics of the gaseous baryonic component and subsequently star formation.

Rindler-Daller, Tanja [Department of Astronomy and Texas Cosmology Center, University of Texas at Austin (United States); Institut fuer Theoretische Physik, Universitaet zu Koeln, Cologne (Germany); Shapiro, Paul R. [Department of Astronomy and Texas Cosmology Center, University of Texas at Austin (United States)

2010-11-03T23:59:59.000Z

385

Control of magnetic vortex chirality in square ring micromagnets Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 and Materials Science  

E-Print Network (OSTI)

Control of magnetic vortex chirality in square ring micromagnets A. Libála Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 and Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 M. Grimsditch Materials Science Division, Argonne National Laboratory

Metlushko, Vitali

386

Reduction in anti-ferromagnetic interactions in ion-beam deposited Fe{sub 3}O{sub 4} thin films  

SciTech Connect

Phase pure Fe{sub 3}O{sub 4} thin films of thickness {approx}42 nm have been prepared on the Si(100) substrate by reactive ion beam sputtering in the growth temperature range of 150-250 deg. C. A high degree of phase purity in the 175 deg. C sample has been confirmed by the XRD, Raman shift, and R-T measurements. The polycrystalline films show a sharp Verway transition as supported by temperature dependent resistivity, AC susceptibility, and coercivity behavior. The significant feature of these films is the early saturation of their room temperature magnetization at {approx}400 mT, indicating the presence of low anti-ferromagnetic competitions in sharp contrast to most of the previous reports. The noticeable reduction of anti-phase boundaries and its dependence on growth temperature has been correlated with the energetic ion-beam deposition process, and explained in terms of the of ionic vacancy migration approach of Eerenstein et al.[Phys. Rev. B 68, 014428 (2003)]. The electronic conduction of these films is governed by near-neighbor hopping above 240 K and Shklovskii-Efros variable range hopping below this transition temperature.

Kumar, Ankit; Pandya, Dinesh K.; Chaudhary, Sujeet [Thin Film Laboratory, Indian Institute of Technology Delhi, New Delhi 110016 (India)

2012-04-01T23:59:59.000Z

387

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

E-Print Network (OSTI)

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.

C. Kuelske; U. A. Rozikov

2014-11-21T23:59:59.000Z

388

Neutron scattering study on f-electron states in PrCu4Au  

SciTech Connect

Neutron scattering studies were carried out for investigating heavy-electron-like behaviors of PrCu4Au. Excitation spectra are composed of crystal-field (CF) excitations in the Pr3+4f2 electron configuration and a broad component. The CF splitting ground state is a triplet 5. The type-II antiferromagnetic ordering characterized by the propagation vector (1/2, 1/2, 1/2) appears below approximately 4 K. The powder diffraction pattern is reproduced by the ordered magnetic moments aligning along the direction perpendicular to the propagation vector. The magnitude of the ordered magnetic moment is evaluated as 1.36uB/Pr, which is less than 2.0uB/Pr expected from the 5 ground state. Dual electronic states of both localized and itinerant character are inferred.

Iwasa, Kazuaki [Tohoku University, Japan; Kobayashi, Hiroki [Tohoku University, Japan; Saito, Kotaro [Tohoku University, Japan; Tomiyasu, Dr. Keisuke [Tohoku University, Japan; Zhang, Shuai [Hiroshima University, Japan; Isikawa, Yosikazu [Toyama University, Japan; Mignot, Jean-Michel [Laboratoire Leon Brillouin, France; Andre, G. [Laboratoire Leon Brillouin, France; Kawana, Kaichi [KEK, Tsukuba, Ibaraki, Japan; Kolesnikov, Alexander I [ORNL; Savici, Andrei T [ORNL; Granroth, Garrett E [ORNL

2014-01-01T23:59:59.000Z

389

Spin- and isospin-polarized states of nuclear matter in the Dirac-Brueckner-Hartree-Fock model  

E-Print Network (OSTI)

Spin-polarized isospin asymmetric nuclear matter is studied within the Dirac-Brueckner-Hartree-Fock approach. After a brief review of the formalism, we present and discuss the self-consistent single-particle potentials at various levels of spin and isospin asymmetry. We then move to predictions of the energy per particle, also under different conditions of isospin and spin polarization. Comparison with the energy per particle in isospin symmetric or asymmetric unpolarized nuclear matter shows no evidence for a phase transition to a spin ordered state, neither ferromagnetic nor antiferromagnetic.

Francesca Sammarruca

2011-04-03T23:59:59.000Z

390

Spin- and isospin-polarized states of nuclear matter in the Dirac-Brueckner-Hartree-Fock model  

E-Print Network (OSTI)

Spin-polarized isospin asymmetric nuclear matter is studied within the Dirac-Brueckner-Hartree-Fock approach. After a brief review of the formalism, we present and discuss the self-consistent single-particle potentials at various levels of spin and isospin asymmetry. We then move to predictions of the energy per particle, also under different conditions of isospin and spin polarization. Comparison with the energy per particle in isospin symmetric or asymmetric unpolarized nuclear matter shows no evidence for a phase transition to a spin ordered state, neither ferromagnetic nor antiferromagnetic.

Sammarruca, Francesca

2011-01-01T23:59:59.000Z

391

Probing the anisotropic vortex lattice in the Fe-based superconductor KFe2As2 using small angle neutron scattering  

SciTech Connect

Using small angle neutron scattering, the anisotropy of the magnetic vortex lattice (VL), in the heavily hole-doped pnictide superconductor, KFe2As2, was studied. Well-ordered VL scattering patterns were measured with elds applied in directions between B k c and the basal plane, rotating either towards [100] or [110]. Slightly distorted hexagonal patterns were observed when B k c. However, the scattering pattern distorted strongly as the eld was rotated away from the c- axis. At low eld, the arrangement of vortices is strongly aected by the anisotropy of penetration depth in the plane perpendicular to the eld. By tting the distortion with the anisotropic London model, we obtained an estimate of 3:4 for the anisotropy factor, , between the in-plane and c-axis penetration depths at the lowest temperature studied. The results further reveal VL phase transitions as a function of eld direction. We discuss these transitions using the "Hairy Ball" theorem.

Debeer-Schmitt, Lisa M [ORNL] [ORNL; Dewhurst, Charles [Institut Laue-Langevin (ILL)] [Institut Laue-Langevin (ILL); Kikuchi, Hiroko [Ochanomizu University, Japan] [Ochanomizu University, Japan; Cameron, Alistair [University of Birmingham, The, Birmingham, United Kingdom] [University of Birmingham, The, Birmingham, United Kingdom; Heslop, Richard [University of Birmingham, The, Birmingham, United Kingdom] [University of Birmingham, The, Birmingham, United Kingdom; Forgan, E. M. [University of Birmingham, The, Birmingham, United Kingdom] [University of Birmingham, The, Birmingham, United Kingdom; Bowell, Charlotte [University of Cambridge] [University of Cambridge; White, Jonathon [Laboratory for Neutron Scattering ETHZ & PSI] [Laboratory for Neutron Scattering ETHZ & PSI; Gavilano, Jorge [ETH Zurich, Switzerland] [ETH Zurich, Switzerland

2013-01-01T23:59:59.000Z

392

Reduction of aerodynamic forces on a minivan by a pair of vortex generators of a pocket type  

Science Journals Connector (OSTI)

Reduction of the aerodynamic forces on a minivan has been achieved using a pair of pockets at the left and the right sides, respectively, of the rear roof end of the vehicle. The two pockets generate cross-streamwise vortices that cause the turbulent kinetic energy to increase in the boundary layer in the downstream of the two pockets. This increased turbulent kinetic energy induces the flow separation to be delayed further downstream along the vehicle back. Unlike the common Vortex Generators (VGs) of extrusive type, these VGs of a pocket type do not cause any additional drag by themselves. This paper investigates numerically the effects of pockets on the reduction of the aerodynamic forces and the flow field around a minivan.

Inchul Kim; Hualei Chen

2010-01-01T23:59:59.000Z

393

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

SciTech Connect

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.

Gollahalli, S.R.

1994-01-01T23:59:59.000Z

394

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

SciTech Connect

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.

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

1994-01-01T23:59:59.000Z

395

PHYSICAL REVIEW B 85, 134414 (2012) Nonlinear motion of magnetic vortex cores during fast magnetic pulses  

E-Print Network (OSTI)

pulses Keiki Fukumoto* Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198, Japan 351-0198, Japan Toyohiko Kinoshita Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679 Kuniaki Arai Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan

Otani, Yoshichika

396

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

SciTech Connect

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.

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

397

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

E-Print Network (OSTI)

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...

Zhang, Ping; Zhao, Xian-Geng

2010-01-01T23:59:59.000Z

398

Ambient-Pressure Bulk Superconductivity Deep in the Magnetic State of CeRhIn5  

SciTech Connect

Specific heat, magnetic susceptibility and electrical transport measurements were performed at ambient pressure on high-quality single crystal specimens of CeRhIn5 down to ultra-low temperatures. We report signatures of an anomaly observed in all measured quantities consistent with a bulk phase transition to a superconducting state at T{sub c}=110 mK. Occurring far below the onset of antiferromagnetism at T{sub N}=3.8 K, this transition appears to involve a significant portion of the available low-temperature density of electronic states, exhibiting an entropy change in line with that found in other members of the 115 family of superconductors tuned away from quantum criticality.

Paglione,J.; Ho, P.; Maple, M.; Tanatar, M.; Taillefer, L.; Lee, Y.; Petrovic, C.

2008-01-01T23:59:59.000Z

399

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

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.

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

400

United States  

Office of Legacy Management (LM)

- I - I United States Department of Energy D lSCk Al M E R "This book was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Microsoft PowerPoint - Misewich_Vortex2011 [Read-Only]  

NLE Websites -- All DOE Office Websites (Extended Search)

and Opportunities in the Large Scale and Opportunities in the Large Scale Integration of Renewable Energy into the Electric Grid Jim Misewich Associate Laboratory Director, Brookhaven National Laboratory New York State Smart Grid Consortium Drivers for RPS reduced carbon emission encourage alternative energy prepare for electrification of transportation replace foreign oil with renewable electricity jobs and economic growth 30 states and DC have RPS typically 20% renewable power by 2020 or 2030 most aggressive: CA - 33% by 2020 NY - 30% by 2015, 80% by 2050 Renewable Portfolio Standards http://www.ferc.gov/market-oversight/othr- mkts/renew/othr-rnw-eeps.pdf American Physical Society Panel on Public Affairs (POPA) January 2011 Co-chairs:

402

Vortex characterisation of frustration in the 2d Ising spin glass  

E-Print Network (OSTI)

The frustrated Ising model on a two-dimensional lattice with open boundary conditions is revisited. A hidden Z2 gauge symmetry relates models with different frustrations which, however, share the same partition function. By means of a duality transformation, it is shown that the partition function only depends on the distribution of gauge invariant vortices on the lattice. We finally show that the exact ground state energy can be calculated in polynomial time using Edmonds' algorithm.

K. Langfeld; M. Quandt; W. Lutz; H. Reinhardt

2010-12-16T23:59:59.000Z

403

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

SciTech Connect

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.

Ahsan Choudhuri

2011-03-31T23:59:59.000Z

404

Volume State  

Gasoline and Diesel Fuel Update (EIA)

22 22 Volume State State or Country From/To Receipts/ Imports From Deliveries/ Exports To Net a Alabama Florida .................................................................. 0 722,558 -722,558 Georgia................................................................. 0 1,352,308 -1,352,308 Gulf of Mexico....................................................... 123,132 0 123,132 Mississippi ............................................................ 2,758,595 0 2,758,595 Tennessee............................................................ 1,744 764,749 -763,005 Total..................................................................... 2,883,471 2,839,615 43,856

405

Assessment of Rich-Burn, Quick-Mix, Lean-Burn Trapped Vortex Combustor for Stationary Gas Turbines  

SciTech Connect

This paper describes the evaluation of an alternative combustion approach to achieve low emissions for a wide range of fuel types. This approach combines the potential advantages of a staged rich-burn, quick-mix, lean-burn (RQL) combustor with the revolutionary trapped vortex combustor (TVC) concept. Although RQL combustors have been proposed for low-Btu fuels, this paper considers the application of an RQL combustor for high-Btu natural gas applications. This paper will describe the RQL/TVC concept and experimental results conducted at 10 atm (1013 kPa or 147 psia) and an inlet-air temperature of 644 K (700°F). The results from a simple network reactor model using detailed kinetics are compared to the experimental observations. Neglecting mixing limitations, the simplified model suggests that NOx and CO performance below 10 parts per million could be achieved in an RQL approach. The CO levels predicted by the model are reasonably close to the experimental results over a wide range of operating conditions. The predicted NOx levels are reasonably close for some operating conditions; however, as the rich-stage equivalence ratio increases, the discrepancy between the experiment and the model increases. Mixing limitations are critical in any RQL combustor, and the mixing limitations for this RQL/TVC design are discussed.

Douglas L. Straub; Kent H. Casleton; Robie E. Lewis; Todd G. Sidwell; Daniel J. Maloney; George A. Richards

2005-01-01T23:59:59.000Z

406

United States  

Office of Legacy Management (LM)

Office of Research and EPA 600/R-941209 Environmental Protection Development January 1993 Agency Washington, DC 20460 Offsite Environmental 57,,7 Monitoring Report Radiation Monitoring Around United States Nuclear Test Areas, Calendar Year 1992 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY OFFICE OF RESEARCH AND DEVELOPMENT ENVIRONMENTAL MONITORING SYSTEMS LABORATORY-LAS VEGAS P.O. BOX 93478 LAS VEGAS. NEVADA 891 93-3478 702/798-2100 Dear Reader: Since 1954, the U.S. Environmental Protection Agency (EPA) and its predecessor the U.S, Public Health Service (PHs) has conducted radiological monitoring in the offsite areas around United States nuclear test areas. The primary objective of this monitoring has been the protection of the health and safety of

407

United States  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

BP Energy Company BP Energy Company OE Docket No. EA- 3 14 Order Authorizing Electricity Exports to Mexico Order No. EA-3 14 February 22,2007 BP Energy Company Order No. EA-314 I. BACKGROUND Exports of electricity from the United States to a foreign country are regulated by the Department of Energy (DOE) pursuant to sections 301(b) and 402(Q of the Department of Energy Organization Act (42 U.S.C. 7 15 l(b), 7172(f)) and require authorization under section 202(e) of the Federal Power Act (FPA) (16 U.S.C.S24a(e)) . On May 22,2006, BP Energy Company (BP Energy) applied to DOE for an authorization to transmit electric energy from the United States to Mexico as a power marketer. BP Energy proposes to purchase surplus electric energy from electric utilities and other suppliers within the United States and to export that energy to ~Mexico. The cnergy

408

State Summaries  

Gasoline and Diesel Fuel Update (EIA)

46. 46. Percent Distribution of Natural Gas Supply and Disposition by State, 1996 Table State Estimated Proved Reserves (dry) Marketed Production Total Consumption Alabama................................................................... 3.02 2.69 1.48 Alaska ...................................................................... 5.58 2.43 2.04 Arizona..................................................................... NA 0 0.55 Arkansas.................................................................. 0.88 1.12 1.23 California.................................................................. 1.25 1.45 8.23 Colorado .................................................................. 4.63 2.90 1.40 Connecticut.............................................................. 0 0 0.58 D.C...........................................................................

409

United States  

Office of Legacy Management (LM)

WASHINGTON, TUESDAY, JUNE 28, 1983 @nngmeional Ruord United States of America .__ -- . . ,- PROCEEDINGS AND DEBATES OF THE 9@ CONGRESS, FIRST SESSION United States Government Printing Office SUPERINTENDENT OF DOCUMENTS Washmgton, D C 20402 OFFICIAL BUSINESS Penalty Ior pwate use. $xX Congresstonal Record (USPS 087-390) Postage and Fees Pad U S Government Prlnhng 0ffv.X 375 SECOND CLASS NEWSPAPER H.4578 ' C.QNGRESSIONAL RECORD - HOUSE June 28, 1983 H.J. Res. 273: Mr. BOUND. Mr. W~.XMAN. Mr. OBERSTAR, Mr. BEDELL. Mr. BONER of Tennessee, Mr. OWENS. Mr. DAUB, Mr. CONTE. Mr. RAHALL; Mr. GRAY, Mr. VANDER JACT. Mr. TRAKLER, and Mr. Vxrrro. H. Con. Res. 107: Mr. KASICH. Mr. AUCOIN. Mr. CARPER, and Mr. SIZHFIJER. H. Con. Res. 118: Mr. FISH. Mr. LANTOS.

410

United States  

Office of Legacy Management (LM)

ongrees;ional Record ongrees;ional Record United States of America __._ -.. I. :- PROCEEDINGS AND DEBATES OF THE 9tth CONGRESS, FIRST SESSION United States Government Printing Office SUPERINTENDENT OF DOCUMENTS Washmcqton. Cl C 20402 OFFICIAL BUSINESS Penalty Ior pwate use. $300 Congressmal Record (USPS 087-390) Postage and Fees Pad U S Governme3n:jPnntmg OfIce SECOND CLASS NEWSPAPER H.4578 ' June 28, 1983 -: I H.J. Res. 273: Mr. BOLAND, Mr. WA-. Mr. OBERSTAFC, M' r. BEDELL, Mr. BONER of Tennessee, Mr. OWENS. Mr. DAUB. Mr. CONTE. Mr. RAHALL,. Mr. GRAY, Mr. VANDER JAGT. Mr. TRAKLER. and Mr. VENTO. H. Con. Res. iO7: Mr. KASICH. Mr. ALCOIN. Mr. CARPER. and Mr. SCHEUER. H. Con. Res. 118: Mr. FISH, Mr. LANTOS. Mr. KILDEE. Mr. SOLARZ Mr. Bmrr, Mr. BELWLL, Mr. RANG~L, Mr. DYMALLY. Mr.

411

United States  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

E-T Global Energy, LLC E-T Global Energy, LLC OE Docket No. EA-381 Order Authorizing Electricity Exports to Mexico Order No. EA-381 June 10, 2011 I. BACKGROUND E-T Global Energy, LLC Order No. EA-381 Exports of electricity from the United States to a foreign country are regulated by the Department of Energy (DOE) pursuant to sections 301(b) and 402(f) of the Department ofEnergy Organization Act (42 U.S.C. 7151(b), 7172(f)) and require authorization under section 202(e) ofthe Federal Power Act (FPA) (16 U.S.C.824a(e)) 1 * On May 10,2011, DOE received an application from E-T Global Energy, LLC (E-T Global) for authority to transmit electric energy from the United States to Mexico for five years as a power marketer using existing international transmission facilities. E-

412

United States  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Bangor Hydro-Electric Company Bangor Hydro-Electric Company OE Docket No. PP-89-1 Amendment to Presidential Permit Order No. PP-89-1 December 30,2005 PRESIDENTIAL PERMIT AMENDMENT Bangor Hydro-Electric Company Order No. PP-89-1 I. BACKGROUND The Department of Energy (DOE) has responsibility for implementing Executive Order (E.O.) 10485, as amended by E.O. 12038, which requires the issuance of a Presidential permit by DOE before electric trans~nission facilities may be constructed, operated, maintained, or connected at the borders of the United States. DOE may issue such a permit if it determines that the permit is in the public interest and after obtaining favorable recommendations from the U.S. Departments of State and Defense. On December 16, 1988, Bangor Hydro-Electric Company (BHE) applied to DOE

413

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

E-Print Network (OSTI)

Supercooled liquids and the glass transition. Nature 410, [in molecular and electronic glasses. Rep. Prog. Phys. 59,disorder-induced spin glass state and nanometer scale

Zhou, S.Y.

2014-01-01T23:59:59.000Z

414

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

SciTech Connect

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.

Manohar S. Sohal

2005-09-01T23:59:59.000Z

415

Massive Dirac surface states in topological insulator/magnetic insulator heterostructures  

Science Journals Connector (OSTI)

Topological insulators are new states of matter with a bulk gap and robust gapless surface states protected by time-reversal symmetry. When time-reversal symmetry is broken, the surface states are gapped, which induces a topological response of the system to electromagnetic field—the topological magnetoelectric effect. In this paper we study the behavior of topological surface states in heterostructures formed by a topological insulator and a magnetic insulator. Several magnetic insulators with compatible magnetic structure and relatively good lattice matching with topological insulators Bi2Se3, Bi2Te3, Sb2Te3 are identified, and the best candidate material is found to be MnSe, an antiferromagnetic insulator. We perform first-principles calculations in Bi2Se3/MnSe superlattices and obtain the surface state band structure. The magnetic exchange coupling with MnSe induces a gap of ?54 meV at the surface states. In addition we tune the distance between Mn ions and the topological insulator surface to study the distance dependence of the exchange coupling.

Weidong Luo and Xiao-Liang Qi

2013-02-19T23:59:59.000Z

416

United States  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

5 5 United States Department of Energy Southeastern Power Administration Wholesale Power Rate Schedule CC-1-I Availability: This rate schedule shall be available to public bodies and cooperatives served through the facilities of Carolina Power & Light Company, Western Division (hereinafter called the Customers). Applicability: This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek, Cheatham, Old Hickory, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being hereinafter called collectively the "Cumberland Projects") and sold in wholesale quantities. Character of Service: The electric capacity and energy supplied hereunder will be three-phase alternating

417

United States  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

TexMex Energy, LLC TexMex Energy, LLC OE Docket No. EA-294-A Order Authorizing Electricity Exports to Mexico Order No. EA-294-A February 22, 2007 TexMex Energy, LLC Order No. EA-294-A I. BACKGROUND Exports of electricity from the United States to a foreign count~y are regulated by the Department of Energy (DOE) pursuant to sections 301(b) and 402(f) of the Department of Energy Organization Act (42 U.S.C. 7 15 1 (b), 71 72(f)) and require authorization under section 202(e) of the Federal Power Act (FPA) (16 U.S.C.824a(e)) . On August 25,2004, DOE issued Order No. EA-294 authorizing TexMex Energy LLC (TexMex) to transmit electric energy fiom the United States to Mexico as a power marketer. That authority expired on August 25, 2006. On September 8, 2006, TexMex applied to renew the electricity export authority

418

State Volume  

Gasoline and Diesel Fuel Update (EIA)

Volume of Natural Gas Delivered to Processing Plants (million cubic feet) Total Liquids Extracted (thousand barrels) Extraction Loss Located Within the State Located Outside of the State Total Processed Volume (million cubic feet Estimated Heat Content (billion Btu) Alabama...................... 111,656 2,614 114,270 4,476 5,810 18,610 Alaska ......................... 2,987,364 0 2,987,364 33,346 38,453 148,444 Arkansas..................... 214,868 161 215,029 237 474 977 California..................... 240,566 0 240,566 9,798 12,169 41,037 Colorado ..................... 493,748 1,249 494,997 16,891 23,420 63,411 Florida......................... 5,900 0 5,900 1,130 1,143 4,202 Illinois.......................... 578 0 578 63 64 271 Kansas........................ 825,825 2,731 828,556 30,617 41,115 120,221 Kentucky .....................

419

United States  

Gasoline and Diesel Fuel Update (EIA)

United States United States Coal ................................................ 4,367 4,077 4,747 4,181 4,473 4,125 4,983 4,330 4,414 4,003 4,796 4,178 4,344 4,479 4,348 Natural Gas .................................... 2,802 2,843 3,694 2,863 2,713 2,880 3,636 2,707 2,792 2,972 3,815 2,849 3,052 2,986 3,109 Petroleum (a) .................................. 74 73 81 67 73 70 75 66 75 70 76 66 74 71 71 Other Gases ................................... 32 33 36 32 32 34 37 33 33 35 39 34 33 34 35 Nuclear ........................................... 2,176 2,044 2,257 2,170 2,106 2,037 2,167 2,010 2,144 2,074 2,206 2,055 2,162 2,080 2,120 Renewable Energy Sources: Conventional Hydropower ........... 736 886 716 633 765 887 708 646 767 919 729 659 742 751 768 Wind ............................................ 491 520 353 449 477 521 379 475

420

United States  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Tenaslta Power Services Co. Tenaslta Power Services Co. OE Docket No. EA-243-A Order Authorizing Electricity Exports to Canada Order No. EA-243-A March 1,2007 Tenaska Power Services Co. Order No. EA-243-A I. BACKGROUND Exports of elcctricity from the United States to a foreign country are regulated by the Department of Energy (DOE) pursuant to sections 30 I(b) and 402(f) of the Departrncnt of' Energy Organizatio~l Act (42 U, S.C. 7 15 1 (b), 7 1 72Cf)) and rcquirc authorization under section 202(e) of the Federal Power Act (FPA) ( Z 6 U. s.c.824a(e)j1. On August 16,2001, DOE issued Order No. EA-243 authorizing Tenaska Power Scrvices Co. (Tenaska) to transmit electric cncrgy from the United States to Canada as a power marketer. That authority expired on August 16,2003. On August 14,2006, Teilaska applied to renew the electricity export authority

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

United States  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

7 7 United States Department of Energy Southeastern Power Administration Wholesale Power Rate Schedule CTV-1-H Availability: This rate schedule shall be available to the Tennessee Valley Authority (hereinafter called TVA). Applicability: This rate schedule shall be applicable to electric capacity and energy generated at the Dale Hollow, Center Hill, Wolf Creek, Old Hickory, Cheatham, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being hereafter called collectively the "Cumberland Projects") and the Laurel Project sold under agreement between the Department of Energy and TVA. Character of Service: The electric capacity and energy supplied hereunder will be three-phase alternating current at a frequency of approximately 60 hertz at the outgoing terminals of the Cumberland

422

United States  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

United States Department of Energy Southeastern Power Administration Wholesale Power Rate Schedule CTVI-1-A Availability: This rate schedule shall be available to customers (hereinafter called the Customer) who are or were formerly in the Tennessee Valley Authority (hereinafter called TVA) service area. Applicability: This rate schedule shall be applicable to electric capacity and energy generated at the Dale Hollow, Center Hill, Wolf Creek, Old Hickory, Cheatham, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being hereafter called collectively the "Cumberland Projects") and the Laurel Project sold under agreement between the Department of Energy and the Customer. Character of Service: The electric capacity and energy supplied hereunder will be three-phase alternating

423

UNITED STATES  

Office of Legacy Management (LM)

f).~<~~ \--\c :y-,ai F p"- KG f).~<~~ \--\c :y-,ai F p"- KG WASHINOTDN 28.0. C. ' -lr ' \ ' ' --- ".I ?--" ' z I. .~;-4.' J frr*o& 2 ii, - - -4 70-147 LRL:JCD JAN !! 8 1958 Oregon Metallurgical Corporation P. 0. Box 484 Albany, Oregon Attention: Mr. Stephen M. Shelton General Manager Gentlemen: Enclosed is Special Nuclear Material License No. SNM-144, as amended. Very 33uly yours, r:; I,;, ll)~gQ""d".- Lyall Johnson Chief, Licensing Branch Division of Licensing & Regulation Enclosure: SNM-144, as amended Distribution: bRO0 Attn: Dr. H.M.Roth DFMusser NMM MMMann INS JCRyan FIN (2) HSteele LRL SRGustavson LRL Document room Formal file Suppl. file Br & Div rf's ' .b liwwArry s/VW- ' q+ ' yj/ 2; 2-' , COP' 1 J JAM01958 -- UNITED STATES ATOMIC ENERGY COMMISSION

424

United States  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

United States Department of Energy Southeastern Power Administration Wholesale Power Rate Schedule JW-2-F Availability: This rate schedule shall be available to the Florida Power Corporation (or Progress Energy Florida, hereinafter called the Company). Applicability: This rate schedule shall be applicable to electric energy generated at the Jim Woodruff Project (hereinafter called the Project) and sold to the Company in wholesale quantities. Points of Delivery: Power sold to the Company by the Government will be delivered at the connection of the Company's transmission system with the Project bus. Character of Service: Electric power delivered to the Company will be three-phase alternating current at a nominal frequency of 60 cycles per second.

425

Resistance and magnetization of La0.7Ca0.3MnO3 bulk at different resistance states induced by electric pulses  

Science Journals Connector (OSTI)

Electric-pulse-induced resistance (EPIR) switching behaviour was observed in bulk La0.7Ca0.3MnO3 polycrystalline. Temperature dependences of resistance and magnetic moment at different resistance states were studied. The metal–insulator phase transition temperature changed with the resistance states, which suggested that the EPIR phenomenon is related to the modulating bulk properties of perovskite manganites. The Curie temperature derived from the magnetic moment measurement did not change with the resistance states, which implied that there was no ferromagnetic–metal and antiferromagnetic–insulator transition occurring in perovskite manganite global materials. These results provided a new evidence for a filamentary mechanism in the EPIR effect.

Z H Wu; Q Wang; W D Yu; D S Shang; X M Li; L D Chen

2008-01-01T23:59:59.000Z

426

Annular vortex combustor  

DOE Patents (OSTI)

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.

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

1992-01-01T23:59:59.000Z

427

State of Connecticut Connecticut State Library  

E-Print Network (OSTI)

State of Connecticut Connecticut State Library Office of the Public Records Administrator www, and §7-109 of the General Statutes of Connecticut (CGS). Definitions "Agency" means a state agency administered by the Connecticut State Library as referred to in CGS §11-8. "Public record" means any recorded

Holsinger, Kent

428

State-Machine Replication  

E-Print Network (OSTI)

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

Venkataramani, Arun

429

Anderson Tower of States and Nematic Order of Spin-1 Bosonic Atoms on a 2D Lattice  

Science Journals Connector (OSTI)

We investigate the structure of the spectrum of antiferromagnetically coupled spin-1 bosons on a square lattice using degenerate perturbation theory and exact diagonalizations of finite clusters. We show that the superfluid phase develops an Anderson tower of states typical of nematic long-range order with broken SU(2) symmetry. We further show that this order persists into the Mott-insulating phase down to zero hopping for one boson per site and down to a critical hopping for two bosons per site, in agreement with mean-field and quantum Monte Carlo results. The connection with the transition between a fragmented condensate and a polar one in a single trap is briefly discussed.

Laurent de Forges de Parny; Hongyu Yang; Frédéric Mila

2014-11-12T23:59:59.000Z

430

Numerical Simulations of Island-Scale Airflow over Maui and the Maui Vortex under Summer Trade Wind Conditions  

Science Journals Connector (OSTI)

The fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) coupled with the Noah land surface model (LSM) is employed to simulate island-scale airflow and circulations over Maui County, Hawaii, under summer trade wind ...

DaNa L. Carlis; Yi-Leng Chen; Vernon R. Morris

2010-07-01T23:59:59.000Z

431

State of the State's Rural Health  

E-Print Network (OSTI)

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

Veiga, Pedro Manuel Barbosa

432

Monte Carlo study of two-dimensional Ising dipolar antiferromagnets as a model for rare-earth ordering in the R-Ba-Cu-O compounds (R=rare earth)  

Science Journals Connector (OSTI)

The two-dimensional Ising model with dipolar interactions is studied using Monte Carlo simulation. In the case of a pure dipolar interaction, estimates are obtained for the reduced transition temperature, ?n=2a3kBTn/?eff2 for two particular spin alignments in which the spins are aligned parallel to and perpendicular to the plane, respectively. A comparison with measurements made on RBa2Cu3O7-? (R=Nd,Dy, and Er) and RBa2Cu4O8 (R=Dy and Er) show that the calculated Ne´el temperature falls consistently below that observed experimentally. The model is generalized to include an isotropic intraplanar nearest-neighbor exchange interaction and the Ne´el temperature calculated as a function of the strength of the exchange coupling for configurations in which the spins are aligned perpendicular to the plane. From this estimates of the exchange coupling are obtained for some of these materials. The results obtained from these calculations confirm that the long-range character of the dipolar interaction does not affect the universality class of the two-dimensional Ising antiferromagnet. Extensions of the present analysis are discussed.

A. B. MacIsaac; J. P. Whitehead; K. De’Bell; K. Sowmya Narayanan

1992-09-01T23:59:59.000Z

433

Nozick's minimal state?  

E-Print Network (OSTI)

In his book, Anarchy , State, and Utopia, Robert Nozick argues that the only state that can be justified is the minimal state, a state limited to providing protection for all its citizens. Nozick explains how a minimal state could naturally develop...

Russell, Darrell James

2012-06-07T23:59:59.000Z

434

Vortex-lattice activation energy deduced from irreversibility lines for (PrBa2Cu3-xGaxO7)M/(YBa2Cu3O7)N superlattices  

Science Journals Connector (OSTI)

The activation energy of the vortex structure in high anisotropic (PrBa2Cu3-xGaxO7)M/(YBa2Cu3O7)N superlattices with a layer thickness of the superconductor in the range 1.2–4.8 nm and with no Josephson coupling between the YBa2Cu3O7 elementary layers has been deduced from irreversibility lines Tirr(H). The activation energy is proportional to the thickness of the elementary YBa2Cu3O7 layer and to the logarithm of the field H, whereas it follows a TAFF behavior for a YBa2Cu3O7 single film. The origin of the activation energy is discussed in light of recent theories on vortex dynamic. The anisotropies deduced from both Tirr(H) and the Kosterlitz-Thouless analysis of the resistive transition are found to be strongly correlated.

D. Ravelosona, J. P. Contour, and N. Bontemps

2000-03-01T23:59:59.000Z

435

Generalized coherent states  

E-Print Network (OSTI)

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.

T. G. Philbin

2013-12-18T23:59:59.000Z

436

States & Emerging Energy Technologies  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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...

437

Qutrit Magic State Distillation  

E-Print Network (OSTI)

Magic state distillation (MSD) is a purification protocol that plays a central role in fault tolerant quantum computation. Repeated iteration of the steps of a MSD protocol, generates pure single non-stabilizer states, or magic states, from multiple copies of a mixed resource state using stabilizer operations only. Thus mixed resource states promote the stabilizer operations to full universality. Magic state distillation was introduced for qubit-based quantum computation, but little has been known concerning MSD in higher dimensional qudit-based computation. Here, we describe a general approach for studying MSD in higher dimensions. We use it to investigate the features of a qutrit MSD protocol based on the 5-qutrit stabilizer code. We show that this protocol distills non-stabilizer magic states, and identify two types of states, that are attractors of this iteration map. Finally, we show how these states may be converted, via stabilizer circuits alone, into a state suitable for state injected implementation ...

Anwar, Hussain; Browne, Dan E

2012-01-01T23:59:59.000Z

438

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

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.

GOLDSCHMIDT, YADIN Y.; LIU, Jin-Tao

2007-08-07T23:59:59.000Z

439

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

Energy Savers (EERE)

State Opportunities for Action: Update of States' CHP Activities (ACEEE), October 2003 State Opportunities for Action: Update of States' CHP Activities (ACEEE), October 2003 This...

440

Doorway states and billiards  

SciTech Connect

Whenever a distinct state is immersed in a sea of complicated and dense states, the strength of the distinct state, which we refer to as a doorway, is distributed in their neighboring states. We analyze this mechanism for 2-D billiards with different geometries. One of them is symmetric and integrable, another is symmetric but chaotic, and the third has a capricious form. The fact that the doorway-state mechanism is valid for such highly diverse cases, proves that it is robust.

Franco-Villafane, J. A.; Mendez-Sanchez, R. A. [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, P.O. Box 48-3, 62251 Cuernavaca Mor. (Mexico); Flores, J. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, P.O. Box 20-364, 01000 Mexico, D. F. (Mexico); Centro Internacional de Ciencias, A. C., P.O. Box 6-101 C.P. 62131 Cuernavaca, Mor. (Mexico); Mateos, J. L. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, P.O. Box 20-364, 01000 Mexico, D. F. (Mexico); Novaro, O. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, P.O. Box 20-364, 01000 Mexico, D. F. (Mexico); Seligman, T. H. [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, P.O. Box 48-3, 62251 Cuernavaca Mor. (Mexico); Centro Internacional de Ciencias, A. C., P.O. Box 6-101 C.P. 62131 Cuernavaca, Mor. (Mexico)

2010-12-23T23:59:59.000Z

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Colorado State University Colorado State University  

E-Print Network (OSTI)

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

Stephens, Graeme L.

442

Colorado State University Colorado State University  

E-Print Network (OSTI)

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

Collett Jr., Jeffrey L.

443

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

444

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

445

Ground-state magnetic phase diagram of bow-tie graphene nanoflakes in external magnetic field  

SciTech Connect

The magnetic phase diagram of a ground state is studied theoretically for graphene nanoflakes of bow-tie shape and various sizes in external in-plane magnetic field. The tight-binding Hamiltonian supplemented with Hubbard term is used to model the electronic structure of the systems in question. The existence of the antiferromagnetic phase with magnetic moments localized at the sides of the bow-tie is found for low field and a field-induced spin-flip transition to ferromagnetic state is predicted to occur in charge-undoped structures. For small nanoflake doped with a single charge carrier, the low-field phase is ferrimagnetic and a metamagnetic transition to ferromagnetic ordering can be forced by the field. The critical field is found to decrease with increasing size of the nanoflake. The influence of diagonal and off-diagonal disorder on the mentioned magnetic properties is studied. The effect of off-diagonal disorder is found to be more important than that of diagonal disorder, leading to significantly widened distribution of critical fields for disordered population of nanoflakes.

Sza?owski, Karol, E-mail: kszalowski@uni.lodz.pl, E-mail: kszalowski@wp.pl [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of ?ód?, ul. Pomorska 149/153, 90-236 ?ód? (Poland)

2013-12-28T23:59:59.000Z

446

Experimental study on vortex-induced motions of a semi-submersible platform with four square columns, Part I: Effects of current incidence angle and hull appendages  

Science Journals Connector (OSTI)

An experimental study on Vortex-Induced Motion (VIM) of the semi-submersible platform concept with four square columns is presented. Model tests were carried out to check the influence of different headings and hull appendages (riser supports located at the pontoons; fairleads and the mooring stretches located vertically at the external column faces; and hard pipes located vertically at the internal column faces). The results comprise in-line, transverse and yaw motions, as well as combined motions in the XY plane, drag and lift forces and spectral analysis. The main results showed that VIM in the transverse direction occurred in a range of reduced velocity 4.0 up to 14.0 with amplitude peaks around reduced velocities around 7.0 and 8.0. The largest transverse amplitudes obtained were around 40% of the column width for 30° and 45° incidences. Another important result observed was a considerable yaw motion oscillation, in which a synchronization region could be identified as a resonance phenomenon. The largest yaw motions were verified for the 0° incidence and the maxima amplitudes around 4.5°. The hull appendages located at columns had the greatest influence on the VIM response of the semi-submersible.

Rodolfo T. Gonçalves; Guilherme F. Rosetti; André L.C. Fujarra; Allan C. Oliveira

2012-01-01T23:59:59.000Z

447

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

448

States & Emerging Energy Technologies  

Energy.gov (U.S. Department of Energy (DOE))

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

449

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/ 

450

AASG State Geological Survey  

Energy.gov (U.S. Department of Energy (DOE))

presentation at the April 2013 peer review meeting held in Denver, Colorado.Contributions to the NGDSAASG State Geological Survey

451

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

452

Black brane steady states  

E-Print Network (OSTI)

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.

Amado, Irene

2015-01-01T23:59:59.000Z

453

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

454

Sustainability Cal State Fullerton  

E-Print Network (OSTI)

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

de Lijser, Peter

455

Steady states and oscillatory instability of swirling flow in a cylinder with rotating top and bottom  

E-Print Network (OSTI)

/radius of the cylinder 1.5. The stability analysis showed that there are several most unstable linear modes instability may lead to an appearance and coexistence of more than one oscillating separation vortex bubble by the sudden appearance of a weak meridional recirculation also called ``separation vortex bubble'' near

Gelfgat, Alexander

456

State Emissions Estimates  

Gasoline and Diesel Fuel Update (EIA)

Estimates of state energy-related carbon dioxide emissions Estimates of state energy-related carbon dioxide emissions Because energy-related carbon dioxide (CO 2 ) constitutes over 80 percent of total emissions, the state energy-related CO 2 emission levels provide a good indicator of the relative contribution of individual states to total greenhouse gas emissions. The U.S. Energy Information Administration (EIA) emissions estimates at the state level for energy-related CO 2 are based on data contained in the State Energy Data System (SEDS). 1 The state-level emissions estimates are based on energy consumption data for the following fuel categories: three categories of coal (residential/commercial, industrial, and electric power sector); natural gas; and ten petroleum products including-- asphalt and road oil, aviation gasoline, distillate fuel, jet fuel, kerosene, liquefied petroleum gases

457

Solid-State Lighting: Solid-State Lighting  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Solid-State Lighting Search Solid-State Lighting Search Search Help Solid-State Lighting HOME ABOUT THE PROGRAM R&D PROJECTS MARKET-BASED PROGRAMS SSL BASICS INFORMATION RESOURCES FINANCIAL OPPORTUNITIES EERE » Building Technologies Office » Solid-State Lighting Printable Version Share this resource Send a link to Solid-State Lighting: Solid-State Lighting to someone by E-mail Share Solid-State Lighting: Solid-State Lighting on Facebook Tweet about Solid-State Lighting: Solid-State Lighting on Twitter Bookmark Solid-State Lighting: Solid-State Lighting on Google Bookmark Solid-State Lighting: Solid-State Lighting on Delicious Rank Solid-State Lighting: Solid-State Lighting on Digg Find More places to share Solid-State Lighting: Solid-State Lighting on AddThis.com... Pause/Resume Photo of a large room with people standing around poster boards.

458

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

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

State Energy Officials - 2014 BTO Peer Review State and Local Code Implementation: State Energy Officials - 2014 BTO Peer Review Presenter: Chris Wagner, National Association of...

459

Direct measurement of antiferromagnetic domain fluctuations  

Science Journals Connector (OSTI)

... those on the nearest neighbour Cr atoms. What actually occurs is sinusoidal modulation of this elementary magnetic structure—called a spin density wave (SDW), with wavelength ?? = ? ... . Even though the measurements were done for mesoscopic samples, the effects on the electrical resistance (R) of the switching dynamics were small (?R/R???10-5) and ...

O. G. Shpyrko; E. D. Isaacs; J. M. Logan; Yejun Feng; G. Aeppli; R. Jaramillo; H. C. Kim; T. F. Rosenbaum; P. Zschack; M. Sprung; S. Narayanan; A. R. Sandy

2007-05-03T23:59:59.000Z

460

States | OpenEI  

Open Energy Info (EERE)

States States Dataset Summary Description The State Energy Data System (SEDS) is compiled by the U.S. Energy Information Administration's (EIA); it is a comprehensive database of energy statistics by state (and includes totals for the entire US). SEDS includes estimates of energy production, consumption, prices, and expenditures broken down by energy source and sector. Annual estimates are available from 1960 - 2009 for production and consumption estimates and from 1970 - 2009 for price and expenditure estimates. Source EIA Date Released June 30th, 2011 (3 years ago) Date Updated Unknown Keywords EIA Energy Consumption Energy Expenditures energy prices energy production SEDS State energy data States US Data text/csv icon Complete SEDS dataset as csv (may be too big for Excel) (csv, 40.6 MiB)

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Alabama State Regulations  

NLE Websites -- All DOE Office Websites (Extended Search)

State Regulations » Alabama State Regulations » Alabama State Regulations: Alabama State of Alabama The State Oil and Gas Board of Alabama, under the direction of the State Geologist and Oil and Gas Supervisor, is responsible for the regulation of oil and gas operations. The Board is divided into two administrative regions-north and south. The Board has broad authority in Alabama's oil and gas conservation statutes to promulgate and enforce rules and regulations to ensure the conservation and proper development of Alabama's petroleum resources. A major duty of the Board is to prevent pollution of fresh water supplies by oil, gas, salt water, or other contaminants resulting from oil and gas operations. The Alabama Department of Environmental Management (ADEM) administers the major federal environmental protection laws through regulations governing air pollution, water quality and supply, solid and hazardous waste management.

462

Pennsylvania State University | .EDUconnections  

NLE Websites -- All DOE Office Websites (Extended Search)

Old Main, Credit: George Chriss Old Main, Credit: George Chriss Research Research at Penn State Capabilities and Projects Institutes of Energy and the Environment Huck Institutes of Life Sciences Materials Research Institute Eberly College of Science Alternative Energy Research Research Publications Faculty Expertise Database Research News DOE Research Results Penn State Commencement 2012 United States Secretary of Energy Dr. Steven Chu was the commencement speaker at Penn State's Eberly College of Science 2012 spring graduation ceremony held May 5 at the Bryce Jordan Center on the University Park campus. Read more. Search this site: Search Over the past ten years, more than 28,000 graduate degrees were conferred by Penn State, including over 6,300 doctoral degrees. Resources About Penn State

463

State & Regional Resources  

Energy.gov (U.S. Department of Energy (DOE))

The Bioenergy Technologies Office partners with the National Biomass State and Regional Partnerships' five regional organizations that provide leadership in their regions with regard to policies...

464

State Nuclear Profiles 2010  

Annual Energy Outlook 2012 (EIA)

byproducts, other biomass, geothermal, solar thermal, photovoltaic energy, and wind. Primary energy source Summer capacity (mw) Share of State total (percent) Net...

465

State Gasoline Taxes  

E-Print Network (OSTI)

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...

Learned, Edmund Philip

1925-03-15T23:59:59.000Z

466

State Energy Strategic Planning  

Energy.gov (U.S. Department of Energy (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.

467

Solid-State Lighting: Solid-State Lighting Videos  

NLE Websites -- All DOE Office Websites (Extended Search)

Solid-State Lighting Videos to Solid-State Lighting Videos to someone by E-mail Share Solid-State Lighting: Solid-State Lighting Videos on Facebook Tweet about Solid-State Lighting: Solid-State Lighting Videos on Twitter Bookmark Solid-State Lighting: Solid-State Lighting Videos on Google Bookmark Solid-State Lighting: Solid-State Lighting Videos on Delicious Rank Solid-State Lighting: Solid-State Lighting Videos on Digg Find More places to share Solid-State Lighting: Solid-State Lighting Videos on AddThis.com... Conferences & Meetings Presentations Publications Webcasts Videos Tools Solid-State Lighting Videos On this page you can access DOE Solid-State Lighting (SSL) Program videos. Photo of a museum art gallery with LED lights in track fixtures overhead. The City of Los Angeles LED Streetlight Program

468

Solid-State Lighting: Solid-State Lighting Contacts  

NLE Websites -- All DOE Office Websites (Extended Search)

About the About the Program Printable Version Share this resource Send a link to Solid-State Lighting: Solid-State Lighting Contacts to someone by E-mail Share Solid-State Lighting: Solid-State Lighting Contacts on Facebook Tweet about Solid-State Lighting: Solid-State Lighting Contacts on Twitter Bookmark Solid-State Lighting: Solid-State Lighting Contacts on Google Bookmark Solid-State Lighting: Solid-State Lighting Contacts on Delicious Rank Solid-State Lighting: Solid-State Lighting Contacts on Digg Find More places to share Solid-State Lighting: Solid-State Lighting Contacts on AddThis.com... Contacts Partnerships Solid-State Lighting Contacts For information about Solid-State Lighting, contact James Brodrick Lighting Program Manager Building Technologies Office U.S. Department of Energy

469

State of the States: Fuel Cells in America 2012 | Department...  

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

State of the States: Fuel Cells in America 2012 State of the States: Fuel Cells in America 2012 This report, written by Fuel Cells 2000 and partially funded by the U.S. Department...

470

Langevin vortex dynamics for a layered superconductor in the lowest-Landau-level approximation W. A. Al-Saidi* and D. Stroud  

E-Print Network (OSTI)

. Al-Saidi* and D. Stroud Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA

Stroud, David

471

State Energy Production Data  

Gasoline and Diesel Fuel Update (EIA)

State Energy Data System State Energy Data System Production Estimates Technical Notes For 1960-2011 Estimates Table of Contents Section 1. Introduction ................................................................................................................... 1 Section 2. Coal ............................................................................................................................... 5 Section 3. Crude Oil ....................................................................................................................... 7 Section 4. Natural Gas (Marketed Production) .............................................................................. 9 Section 5. Renewable Energy and Nuclear Energy ..................................................................... 13

472

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

473

EIA - State Nuclear Profiles  

U.S. Energy Information Administration (EIA) Indexed Site

of State total (percent) Net generation (thousand mwh) Share of State total (percent) Nuclear 4,966 4.6 41,335 10.0 Coal 22,335 20.6 150,173 36.5 Hydro and Pumped Storage 689 0.6...

474

Rydberg states of HD  

Science Journals Connector (OSTI)

The triplet nf Rydberg states of HD with n=9–17, L=3, v=1, and R=1,3 have been observed and identified with the laser–molecular-beam method. A 20-eV electron beam excites a collimated HD beam to the metastable 2p ?3 state. Two counterpropagating cw single-frequency laser beams excite the metastable molecule first to the intermediate 3d ?3 state, then to a triplet nf Rydberg state. The transition frequencies between the 3d and nf states have been measured to an accuracy of 0.02 cm-1. The long-range model gives the transition frequencies to an accuracy of approximately 0.1 cm-1. Using these energy-level measurements, the ionization potential of the metastable state has been determined to be 27 460.98(30) cm-1 and the energy difference between the triplet metastable and the singlet ground state has been determined to be 97 105.50(30) cm-1. In addition, the linewidths of the triplet Rydberg states have been measured, giving the autoionization rates.

Sander H. Kim and Eric Mazur

1995-08-01T23:59:59.000Z

475

Compatibility of quantum states  

SciTech Connect

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.

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

476

Compatibility of quantum states  

Science Journals Connector (OSTI)

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.

David Poulin and Robin Blume-Kohout

2003-01-15T23:59:59.000Z

477

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

478

Solid-State Lighting: Solid-State Lighting Manufacturing Workshop  

NLE Websites -- All DOE Office Websites (Extended Search)

Solid-State Lighting Solid-State Lighting Manufacturing Workshop to someone by E-mail Share Solid-State Lighting: Solid-State Lighting Manufacturing Workshop on Facebook Tweet about Solid-State Lighting: Solid-State Lighting Manufacturing Workshop on Twitter Bookmark Solid-State Lighting: Solid-State Lighting Manufacturing Workshop on Google Bookmark Solid-State Lighting: Solid-State Lighting Manufacturing Workshop on Delicious Rank Solid-State Lighting: Solid-State Lighting Manufacturing Workshop on Digg Find More places to share Solid-State Lighting: Solid-State Lighting Manufacturing Workshop on AddThis.com... Conferences & Meetings Past Conferences Presentations Publications Webcasts Videos Tools Solid-State Lighting Manufacturing Workshop Nearly 200 lighting industry leaders, chip makers, fixture and component

479

FY 2009 State Table  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

State Tables State Tables Preliminary February 2008 Office of Chief Financial Officer Department of Energy FY 2009 Congressional Budget Request State Tables Preliminary The numbers depicted in this document represent the gross level of DOE budget authority for the years displayed. The figures include both the discretionary and mandatory funding in the budget. They do not consider revenues/receipts, use of prior year balances, deferrals, rescissions, or other adjustments appropriated as offsets to the DOE appropriations by the Congress. Printed with soy ink on recycled paper State Index Page Number FY 2009 Congressional Budget 1/30/2008 Department Of Energy (Dollars In Thousands) 9:01:45AM Page 1 of 2 FY 2007 Appropriation FY 2008 Appropriation FY 2009 Request State Table 1 1 $27,588

480

FY 2005 State Table  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Office of Management, Budget Office of Management, Budget and Evaluation/CFO February 2004 State Tables State Tables Preliminary Preliminary Department of Energy Department of Energy FY 2005 Congressional Budget FY 2005 Congressional Budget Request Request Office of Management, Budget and Evaluation/CFO February 2004 State Tables State Tables Printed with soy ink on recycled paper Preliminary Preliminary The numbers depicted in this document represent the gross level of DOE budget authority for the years displayed. The figures include both the discretionary and mandatory funding in the budget. They do not consider revenues/receipts, uses of prior year balances, deferrals, rescissions, or other adjustments appropriated as offsets to the DOE appropriations by the Congress. State Index Page Number

Note: This page contains sample records for the topic "antiferromagnetic vortex states" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

FY 2010 State Table  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

State Tables State Tables Preliminary May 2009 Office of Chief Financial Officer FY 2010 Congressional Budget Request State Tables Preliminary The numbers depicted in this document represent the gross level of DOE budget authority for the years displayed. The figures include both the discretionary and mandatory funding in the budget. They do not consider revenues/receipts, use of prior year balances, deferrals, rescissions, or other adjustments appropriated as offsets to the DOE appropriations by the Congress. Printed with soy ink on recycled paper State Index Page Number FY 2010 Congressional Budget 5/4/2009 Department Of Energy (Dollars In Thousands) 2:13:22PM Page 1 of 2 FY 2008 Appropriation FY 2009 Appropriation FY 2010 Request State Table 1 1 $46,946 $48,781 $38,844 Alabama 2 $6,569

482

New York State Regulations  

NLE Websites -- All DOE Office Websites (Extended Search)

New York New York State Regulations: New York State of New York The primary responsibility for regulating oil and gas activities within New York resides with the Bureau of Oil and Gas Regulation in the Division of Mineral Resources (Office of Natural Resources) of the New York State Department of Environmental Conservation (NYSDEC). Other offices and divisions within the NYSDEC administer the major environmental protection laws. Contact New York State Department of Environmental Conservation Division of Mineral Resources Bureau of Oil and Gas Regulation 625 Broadway, 3rd Floor Albany, NY 12233-6500 (518) 402-8056 (phone) (518) 402-8060 (fax) Disposal Practices and Applicable Regulations Environmental conservation rules and regulations are contained in Title 6 of the Official Compilation of Codes, Rules and Regulations of the State of New York (6 NYCRR). The rules and regulations for oil, gas and solution mining are provided in 6 NYCRR Parts 550-559.

483

FY 2006 State Table  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

State Tables State Tables Preliminary Department of Energy FY 2006 Congressional Budget Request Office of Management, Budget and Evaluation/CFO February 2005 State Tables Preliminary Printed with soy ink on recycled paper The numbers depicted in this document represent the gross level of DOE budget authority for the years displayed. The figures include both the discretionary and mandatory funding in the budget. They do not consider revenues/receipts, uses of prior year balances, deferrals, rescissions, or other adjustments appropriated as offsets to the DOE appropriations by the Congress. State Index Page Number FY 2006 Congressional Budget 1/27/2005 Department Of Energy (Dollars In Thousands) 3:32:58PM Page 1 of 2 FY 2004 Comp/Approp FY 2005 Comp/Approp FY 2006 Request State Table

484

state | OpenEI  

Open Energy Info (EERE)

state state Dataset Summary Description The Alabama State Oil and Gas Board publishes well record permits to the public as they are approved. This dataset is comprised of 50 recent well record permits from 2/9/11 - 3/18/11. The dataset lists the well name, county, operator, field, and date approved, among other fields. State's make oil and gas data publicly available for a range of topics. Source Geological Survey of Alabama Date Released February 09th, 2011 (3 years ago) Date Updated March 18th, 2011 (3 years ago) Keywords Alabama board gas oil state well records Data application/vnd.ms-excel icon Well records 2/9/11 - 3/18/11 (xls, 28.7 KiB) Quality Metrics Level of Review Some Review Comment Temporal and Spatial Coverage Frequency Time Period License License Open Data Commons Attribution License

485

FY 2008 State Table  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

State Table State Table Preliminary Department of Energy FY 2008 Congressional Budget Request February 2007 Office of Chief Financial Officer State Table Preliminary Printed with soy ink on recycled paper The numbers depicted in this document represent the gross level of DOE budget authority for the years displayed. The figures include both the discretionary and mandatory funding in the budget. They do not consider revenues/receipts, uses of prior year balances, deferrals, rescissions, or other adjustments appropriated as offsets to the DOE appropriations by the Congress. State Index Page Number FY 2008 Congressional Budget 2/1/2007 Department Of Energy (Dollars In Thousands) 6:53:08AM Page 1 of 2 FY 2006 Appropriation FY 2007 Request FY 2008 Request State Table 1 1 $28,332 $30,341

486

Pseudosteady-state mixed convection inside rotating spherical containers  

SciTech Connect

A computational study of the pseudosteady-state two-dimensional mixed convection within rotating spherical containers is presented. The computations are based on an iterative, finite-volume numerical procedure using primitive dependent variables, whereby the time-dependent continuity, momentum and energy equations in the spherical coordinate system are solved. Natural convection effect is modeled via the Boussinesq approximation. For a fixed Prandtl number of 4.62, parametric studies were performed by varying the Rayleigh number in order to cover the laminar regime adequately. For a given Rayleigh number, the ratio of Gr/Re{sup 2} was varied between 0.1 and 10. Given a Rayleigh number, the streamline patterns maintain their general shape with a dominant rotating vortex. As the forced convection effect becomes less marked, the streamlines exhibit less pronounced gradients near the surface of the sphere. As the rotational effect become more marked, the extent of the deviation from the limiting case of non-rotating spheres becomes more noticed. However, the bottom of the sphere still remains to be the region with enhanced heat transfer. Given a rotational Reynolds number, the streamline patterns are not affected greatly as the natural convection is promoted, however the temperature gradients near the surface are markedly enhanced. It is noticed that as natural convection effects are promoted, the greater portion of the sphere's surface experiences enhanced heat transfer rates. Given a Rayleigh number, the contours of the azimuthal velocity exhibit a nearly vertical equally-spaced pattern suggesting that solid-body rotation for high rotational Reynolds numbers. However, as the natural convection effects are enhanced, the contours become more slanted. The variation of the mean Nusselt number with the Reynolds and Rayleigh numbers is also quantified.

Khodadadi, J.M.; Li, W.; Shi, X.

1999-07-01T23:59:59.000Z

487

Solid-State Lighting: Solid-State Lighting  

NLE Websites -- All DOE Office Websites (Extended Search)

Lighting Lighting Printable Version Share this resource Send a link to Solid-State Lighting: Solid-State Lighting to someone by E-mail Share Solid-State Lighting: Solid-State Lighting on Facebook Tweet about Solid-State Lighting: Solid-State Lighting on Twitter Bookmark Solid-State Lighting: Solid-State Lighting on Google Bookmark Solid-State Lighting: Solid-State Lighting on Delicious Rank Solid-State Lighting: Solid-State Lighting on Digg Find More places to share Solid-State Lighting: Solid-State Lighting on AddThis.com... Pause/Resume Photo of a large room with people standing around poster boards. Register Now for DOE's 11th Annual SSL R&D Workshop January 28-30, join other SSL R&D professionals from industry, government, and academia to learn, share, and shape the future of lighting.

488

The state road map  

SciTech Connect

In the past year, electric industry restructuring has become a hot issue in virtually every state - not only those with high retail rates. So far this year, retail access legislation has been introduced in 23 states, and study bills have been introduced in another nine. Several of these states have already taken action. Oklahoma enacted the Electric Restructuring Act of 1997 in late April, mandating retail choice of generation suppliers by 2002, and legislatures in Maryland, Utah, Arkansas and Idaho adopted study bills. On the regulatory front, formal and substantive commission proceedings are moving forward in well over half the states. State legislatures and regulatory commissions around the country are keenly focused on those states which already enacted retail access legislation and are now slogging through the details of implementation. Even with new laws in place, heated debates on the issues surrounding both deregulation of generation and the evolution of the retail energy service market continue, and delays are possible. Retail energy service companies could begin competing for up to 20 million retail customers next year in Massachusetts, California, New Hampshire and Rhode Island, along with a significant number of new pilot-program customers in Pennsylvania and New York. This article gives a brief progress report on the states closest to retail choice.

Simon, K.M.; Vavro, S.L.; Shapiro, D.

1997-06-01T23:59:59.000Z

489

New State Standards  

E-Print Network (OSTI)

.-State-Funded Buildings ?TAC Rules: ?19.31/?19.32/?19.33/?19.34 ? Chapter 388-TX Health & Safety Code ?Texas Building Energy Performance Stds. ?TAC Rules: ?19.53 ? IECC-IRC 2012 ? SECO Resources ?Q&A 2 CATEE-Dallas 11-09-2011 Texas Design Standards... Chapter 447.004-TX Gov. Code ? State that SECO shall establish and publish mandatory energy and water conservation design standards for each new state building or major renovation project ? SECO shall define ?major renovation project? and shall...

Lopez, F. A.

2011-01-01T23:59:59.000Z

490

By Coal Origin State  

U.S. Energy Information Administration (EIA) Indexed Site

1 1 U.S. Energy Information Administration | Quarterly Coal Distribution Report 2nd Quarter 2011 Alabama ___________________________________________________________________________________________________________________________________ Table OS-1. Domestic coal distribution, by origin State, 2nd Quarter 2011 Origin: Alabama (thousand short tons) Coal Destination State Transportation Mode Electric Power Sector Coke Plants Industrial Plants (excluding Coke) Commercial & Institutional Total Alabama Total 1,896 182 327 - 2,405 Alabama Railroad 1,192 2 74 - 1,268 Alabama River 655 - - - 655 Alabama Truck 50 180 253 - 482 Georgia Total s - - - s Georgia Truck s - - - s Indiana Total - 72 - - 72 Indiana Railroad - 72 - - 72 Tennessee Total - - 7 - 7 Tennessee Truck - - 7 - 7 Origin State Total 1,896

491

California State Regulations  

NLE Websites -- All DOE Office Websites (Extended Search)

California California State Regulations: California State of California The California Department of Conservation's Division of Oil, Gas, and Geothermal Resources oversees the drilling, operation, maintenance, and plugging and abandonment of oil, natural gas, and geothermal wells. The regulatory program emphasizes the development of oil, natural gas, and geothermal resources in the state through sound engineering practices that protect the environment, prevent pollution, and ensure public safety. Other agencies that may be involved in the regulation of drilling wastes include the State Water Resources Control Board and appropriate Regional Water Quality Control Boards, the California Integrated Waste Management Board, the California Air Resources Board and appropriate Air Quality Management Districts or Air Pollution Control Districts, and the Department of Toxic Substances Control.

492

FY 2011 State Table  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

State Tables State Tables Department of Energy FY 2011 Congressional Budget Request DOE/CF-0054 March 2010 Office of Chief Financial Officer State Tables Printed with soy ink on recycled paper The numbers depicted in this document represent the gross level of DOE budget authority for the years displayed. The figures include both the discretionary and mandatory funding in the budget. They do not consider revenues/receipts, use of prior year balances, deferrals, rescissions, or other adjustments appropriated as offsets to the DOE appropriations by the Congress. Department of Energy FY 2011 Congressional Budget Request DOE/CF-0054 State Index Page Number FY 2011 Congressional Budget 1/29/2010 Department Of Energy (Dollars In Thousands) 6:34:40AM Page 1 of 2 FY 2009 Appropriation

493

Kansas State Regulations  

NLE Websites -- All DOE Office Websites (Extended Search)

Kansas Kansas State Regulations: Kansas State of Kansas The Kansas Corporation Commission (KCC) Conservation Division regulates oil and gas operations and protects correlative rights and environmental resources. Otherwise, the Kansas Department of Health and Environment (KDHE) administers the major environmental protection laws. Contact Kansas Corporation Commission (Main Office) 1500 S.W. Arrowhead Road Topeka, KS 66604-2425 (785) 271-3100 (phone) (785) 271-3354 (fax) Conservation Division Finney State Office Building 130 South Market, Room 2078 Wichita, KS 67202-3802 (316) 337-6200 (phone) (316) 337-6211 (fax) Kansas Department of Health and Environment Charles Curtis State Office Building 1000 S.W. Jackson Topeka, KS 66612 (785) 296-1500 (phone) (785) 368-6368 (fax)

494

United States Department of  

E-Print Network (OSTI)

of a typical wind energy production facility, the results warrant further research on the use of acoustic;1 INTRODUCTION Over the past decade, wind energy production capacity in the United States has increased

495

State and Local Incentives  

Energy.gov (U.S. Department of Energy (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. See the following resources for more...

496

State Energy Production Estimates  

U.S. Energy Information Administration (EIA) Indexed Site

State Energy Production Estimates 1960 Through 2012 2012 Summary Tables Table P1. Energy Production Estimates in Physical Units, 2012 Alabama 19,455 215,710 9,525 0 Alaska 2,052...

497

State Nuclear Profiles 2010  

U.S. Energy Information Administration (EIA) Indexed Site

State Nuclear Profiles 2010 State Nuclear Profiles 2010 April 2012 Independent Statistics & Analysis www.eia.gov U.S. Department