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Sample records for hall upper saddle

  1. Solar saddle bags. Solar-Fahrradpacktaschen

    Energy Technology Data Exchange (ETDEWEB)

    Willems, M

    1991-09-12

    The invention consists of the arrangement of solar cells on the upper side of saddle bags of every design (handle bar pocket, bicycle saddle bag etc.) which charge the accumulators in the pack pocket. One can drive the alternator of the bicycle, a transistor radio, a cassette tape recorder, or similar, with the power from the accumulators. The lamp and the taillight of the bicycle can still be used. The solar cells can be attached firmly to the pack pocket. However, they can also be assembled detachably, e.g. by push-buttons or zip-fasteners.

  2. 'Saddle-point' ionization

    International Nuclear Information System (INIS)

    Gay, T.J.; Hale, E.B.; Irby, V.D.; Olson, R.E.; Missouri Univ., Rolla; Berry, H.G.

    1988-01-01

    We have studied the ionization of rare gases by protons at intermediate energies, i.e., energies at which the velocities of the proton and the target-gas valence electrons are comparable. A significant channel for electron production in the forward direction is shown to be 'saddle-point' ionization, in which electrons are stranded on or near the saddle-point of electric potential between the receding projectile and the ionized target. Such electrons yield characteristic energy spectra, and contribute significantly to forward-electron-production cross sections. Classical trajectory Monte Carlo calculations are found to provide qualitative agreement with our measurements and the earlier measurements of Rudd and coworkers, and reproduce, in detail, the features of the general ionization spectra. (orig.)

  3. Codimension n saddle-nodes

    International Nuclear Information System (INIS)

    Gheiner, Jaques

    2014-01-01

    We consider the generic unfolding of a diffeomorphism on a compact C ∞ manifold that is Morse–Smale except for one non-hyperbolic periodic orbit being a codimension n saddle-node (one eigenvalue is 1, the other eigenvalues have norm different from 1). Local and global bifurcations are described. We characterize structural stability of the unfolding, depending on the codimension. A universal model of the unfolding is given when there is stability. Dynamical behaviour is analysed in other cases. (paper)

  4. The Impact of a Health Campaign on Hand Hygiene and Upper Respiratory Illness among College Students Living in Residence Halls.

    Science.gov (United States)

    White, Cindy; Kolble, Robin; Carlson, Rebecca; Lipson, Natasha

    2005-01-01

    Hand hygiene is a key element in preventing the transmission of cold and flu viruses. The authors conducted an experimental-control design study in 4 campus residence halls to determine whether a message campaign about hand hygiene and the availability of gel hand sanitizer could decrease cold and flu illness and school and work absenteeism. Their…

  5. Approximating chaotic saddles for delay differential equations.

    Science.gov (United States)

    Taylor, S Richard; Campbell, Sue Ann

    2007-04-01

    Chaotic saddles are unstable invariant sets in the phase space of dynamical systems that exhibit transient chaos. They play a key role in mediating transport processes involving scattering and chaotic transients. Here we present evidence (long chaotic transients and fractal basins of attraction) of transient chaos in a "logistic" delay differential equation. We adapt an existing method (stagger-and-step) to numerically construct the chaotic saddle for this system. This is the first such analysis of transient chaos in an infinite-dimensional dynamical system, and in delay differential equations in particular. Using Poincaré section techniques we illustrate approaches to visualizing the saddle set, and confirm that the saddle has the Cantor-like fractal structure consistent with a chaotic saddle generated by horseshoe-type dynamics.

  6. Approximating chaotic saddles for delay differential equations

    Science.gov (United States)

    Taylor, S. Richard; Campbell, Sue Ann

    2007-04-01

    Chaotic saddles are unstable invariant sets in the phase space of dynamical systems that exhibit transient chaos. They play a key role in mediating transport processes involving scattering and chaotic transients. Here we present evidence (long chaotic transients and fractal basins of attraction) of transient chaos in a “logistic” delay differential equation. We adapt an existing method (stagger-and-step) to numerically construct the chaotic saddle for this system. This is the first such analysis of transient chaos in an infinite-dimensional dynamical system, and in delay differential equations in particular. Using Poincaré section techniques we illustrate approaches to visualizing the saddle set, and confirm that the saddle has the Cantor-like fractal structure consistent with a chaotic saddle generated by horseshoe-type dynamics.

  7. The Antitriangular Factorization of Saddle Point Matrices

    KAUST Repository

    Pestana, J.

    2014-01-01

    Mastronardi and Van Dooren [SIAM J. Matrix Anal. Appl., 34 (2013), pp. 173-196] recently introduced the block antitriangular ("Batman") decomposition for symmetric indefinite matrices. Here we show the simplification of this factorization for saddle point matrices and demonstrate how it represents the common nullspace method. We show that rank-1 updates to the saddle point matrix can be easily incorporated into the factorization and give bounds on the eigenvalues of matrices important in saddle point theory. We show the relation of this factorization to constraint preconditioning and how it transforms but preserves the structure of block diagonal and block triangular preconditioners. © 2014 Society for Industrial and Applied Mathematics.

  8. Featured Partner: Saddle Creek Logistics Services

    Science.gov (United States)

    This EPA fact sheet spotlights Saddle Creek Logistics as a SmartWay partner committed to sustainability in reducing greenhouse gas emissions and air pollution caused by freight transportation, partly by growing its compressed natural gas (CNG) vehicles for

  9. The Antitriangular Factorization of Saddle Point Matrices

    KAUST Repository

    Pestana, J.; Wathen, A. J.

    2014-01-01

    Mastronardi and Van Dooren [SIAM J. Matrix Anal. Appl., 34 (2013), pp. 173-196] recently introduced the block antitriangular ("Batman") decomposition for symmetric indefinite matrices. Here we show the simplification of this factorization for saddle

  10. 27 CFR 9.203 - Saddle Rock-Malibu.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Saddle Rock-Malibu. 9.203... Saddle Rock-Malibu. (a) Name. The name of the viticultural area described in this section is “Saddle Rock-Malibu”. For purposes of part 4 of this chapter, “Saddle Rock-Malibu” is a term of viticultural...

  11. 36 CFR 34.10 - Saddle and pack animals.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Saddle and pack animals. 34... INTERIOR EL PORTAL ADMINISTRATIVE SITE REGULATIONS § 34.10 Saddle and pack animals. The use of saddle and pack animals is prohibited without a permit from the Superintendent. ...

  12. Hall A

    Data.gov (United States)

    Federal Laboratory Consortium — The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electroand photo-induced reactions at very high luminosity...

  13. Hall C

    Data.gov (United States)

    Federal Laboratory Consortium — Hall C's initial complement of equipment (shown in the figure), includes two general-purpose magnetic spectrometers. The High Momentum Spectrometer (HMS) has a large...

  14. Preconditioners for regularized saddle point matrices

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe

    2011-01-01

    Roč. 19, č. 2 (2011), s. 91-112 ISSN 1570-2820 Institutional research plan: CEZ:AV0Z30860518 Keywords : saddle point matrices * preconditioning * regularization * eigenvalue clustering Subject RIV: BA - General Mathematics Impact factor: 0.533, year: 2011 http://www.degruyter.com/view/j/jnma.2011.19.issue-2/jnum.2011.005/jnum.2011.005. xml

  15. GEODESIC RECONSTRUCTION, SADDLE ZONES & HIERARCHICAL SEGMENTATION

    Directory of Open Access Journals (Sweden)

    Serge Beucher

    2011-05-01

    Full Text Available The morphological reconstruction based on geodesic operators, is a powerful tool in mathematical morphology. The general definition of this reconstruction supposes the use of a marker function f which is not necessarily related to the function g to be built. However, this paper deals with operations where the marker function is defined from given characteristic regions of the initial function f, as it is the case, for instance, for the extrema (maxima or minima but also for the saddle zones. Firstly, we show that the intuitive definition of a saddle zone is not easy to handle, especially when digitised images are involved. However, some of these saddle zones (regional ones also called overflow zones can be defined, this definition providing a simple algorithm to extract them. The second part of the paper is devoted to the use of these overflow zones as markers in image reconstruction. This reconstruction provides a new function which exhibits a new hierarchy of extrema. This hierarchy is equivalent to the hierarchy produced by the so-called waterfall algorithm. We explain why the waterfall algorithm can be achieved by performing a watershed transform of the function reconstructed by its initial watershed lines. Finally, some examples of use of this hierarchical segmentation are described.

  16. Rotating saddle trap as Foucault's pendulum

    Science.gov (United States)

    Kirillov, Oleg N.; Levi, Mark

    2016-01-01

    One of the many surprising results found in the mechanics of rotating systems is the stabilization of a particle in a rapidly rotating planar saddle potential. Besides the counterintuitive stabilization, an unexpected precessional motion is observed. In this note, we show that this precession is due to a Coriolis-like force caused by the rotation of the potential. To our knowledge, this is the first example where such a force arises in an inertial reference frame. We also propose a simple mechanical demonstration of this effect.

  17. Assessment of saddle-point-mass predictions for astrophysical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kelic, A.; Schmidt, K.H.

    2005-07-01

    Using available experimental data on fission barriers and ground-state masses, a detailed study on the predictions of different models concerning the isospin dependence of saddle-point masses is performed. Evidence is found that several macroscopic models yield unrealistic saddle-point masses for very neutron-rich nuclei, which are relevant for the r-process nucleosynthesis. (orig.)

  18. Maximal saddle solution of a nonlinear elliptic equation involving the ...

    Indian Academy of Sciences (India)

    College of Mathematics and Econometrics, Hunan University, Changsha 410082, China. E-mail: huahuiyan@163.com; duzr@hnu.edu.cn. MS received 3 September 2012; revised 20 December 2012. Abstract. A saddle solution is called maximal saddle solution if its absolute value is not smaller than those absolute values ...

  19. Fractional Quantum Hall States in a Ge Quantum Well.

    Science.gov (United States)

    Mironov, O A; d'Ambrumenil, N; Dobbie, A; Leadley, D R; Suslov, A V; Green, E

    2016-04-29

    Measurements of the Hall and dissipative conductivity of a strained Ge quantum well on a SiGe/(001)Si substrate in the quantum Hall regime are reported. We analyze the results in terms of thermally activated quantum tunneling of carriers from one internal edge state to another across saddle points in the long-range impurity potential. This shows that the gaps for different filling fractions closely follow the dependence predicted by theory. We also find that the estimates of the separation of the edge states at the saddle are in line with the expectations of an electrostatic model in the lowest spin-polarized Landau level (LL), but not in the spin-reversed LL where the density of quasiparticle states is not high enough to accommodate the carriers required.

  20. The Taylor saddle effacement: a new technique for correction of saddle nose deformity.

    Science.gov (United States)

    Taylor, S Mark; Rigby, Matthew H

    2008-02-01

    To describe a novel technique, the Taylor saddle effacement (TSE), for correction of saddle nose deformity using autologous grafts from the lower lateral cartilages. A prospective evaluation of six patients, all of whom had the TSE performed. Photographs were taken in combination with completion of a rhinoplasty outcomes questionnaire preoperatively and at 6 months. The questionnaire included a visual analogue scale (VAS) of nasal breathing and a rhinoplasty outcomes evaluation (ROE) of nasal function and esthetics. All six patients had improvement in both their global nasal airflow on the VAS and on their ROE that was statistically significant. The mean preoperative VAS score was 5.8 compared with our postoperative mean of 8.5 of a possible 10. Mean ROE scores improved from 34.7 to 85.5. At 6 months, all patients felt that their nasal appearance had improved. The TSE is a simple and reliable technique for correction of saddle nose deformity. This prospective study has demonstrated improvement in both nasal function and esthetics when it is employed.

  1. Complex economic dynamics: Chaotic saddle, crisis and intermittency

    International Nuclear Information System (INIS)

    Chian, Abraham C.-L.; Rempel, Erico L.; Rogers, Colin

    2006-01-01

    Complex economic dynamics is studied by a forced oscillator model of business cycles. The technique of numerical modeling is applied to characterize the fundamental properties of complex economic systems which exhibit multiscale and multistability behaviors, as well as coexistence of order and chaos. In particular, we focus on the dynamics and structure of unstable periodic orbits and chaotic saddles within a periodic window of the bifurcation diagram, at the onset of a saddle-node bifurcation and of an attractor merging crisis, and in the chaotic regions associated with type-I intermittency and crisis-induced intermittency, in non-linear economic cycles. Inside a periodic window, chaotic saddles are responsible for the transient motion preceding convergence to a periodic or a chaotic attractor. The links between chaotic saddles, crisis and intermittency in complex economic dynamics are discussed. We show that a chaotic attractor is composed of chaotic saddles and unstable periodic orbits located in the gap regions of chaotic saddles. Non-linear modeling of economic chaotic saddle, crisis and intermittency can improve our understanding of the dynamics of financial intermittency observed in stock market and foreign exchange market. Characterization of the complex dynamics of economic systems is a powerful tool for pattern recognition and forecasting of business and financial cycles, as well as for optimization of management strategy and decision technology

  2. Acceleration of saddle-point searches with machine learning

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Andrew A., E-mail: andrew-peterson@brown.edu [School of Engineering, Brown University, Providence, Rhode Island 02912 (United States)

    2016-08-21

    In atomistic simulations, the location of the saddle point on the potential-energy surface (PES) gives important information on transitions between local minima, for example, via transition-state theory. However, the search for saddle points often involves hundreds or thousands of ab initio force calls, which are typically all done at full accuracy. This results in the vast majority of the computational effort being spent calculating the electronic structure of states not important to the researcher, and very little time performing the calculation of the saddle point state itself. In this work, we describe how machine learning (ML) can reduce the number of intermediate ab initio calculations needed to locate saddle points. Since machine-learning models can learn from, and thus mimic, atomistic simulations, the saddle-point search can be conducted rapidly in the machine-learning representation. The saddle-point prediction can then be verified by an ab initio calculation; if it is incorrect, this strategically has identified regions of the PES where the machine-learning representation has insufficient training data. When these training data are used to improve the machine-learning model, the estimates greatly improve. This approach can be systematized, and in two simple example problems we demonstrate a dramatic reduction in the number of ab initio force calls. We expect that this approach and future refinements will greatly accelerate searches for saddle points, as well as other searches on the potential energy surface, as machine-learning methods see greater adoption by the atomistics community.

  3. Acceleration of saddle-point searches with machine learning

    International Nuclear Information System (INIS)

    Peterson, Andrew A.

    2016-01-01

    In atomistic simulations, the location of the saddle point on the potential-energy surface (PES) gives important information on transitions between local minima, for example, via transition-state theory. However, the search for saddle points often involves hundreds or thousands of ab initio force calls, which are typically all done at full accuracy. This results in the vast majority of the computational effort being spent calculating the electronic structure of states not important to the researcher, and very little time performing the calculation of the saddle point state itself. In this work, we describe how machine learning (ML) can reduce the number of intermediate ab initio calculations needed to locate saddle points. Since machine-learning models can learn from, and thus mimic, atomistic simulations, the saddle-point search can be conducted rapidly in the machine-learning representation. The saddle-point prediction can then be verified by an ab initio calculation; if it is incorrect, this strategically has identified regions of the PES where the machine-learning representation has insufficient training data. When these training data are used to improve the machine-learning model, the estimates greatly improve. This approach can be systematized, and in two simple example problems we demonstrate a dramatic reduction in the number of ab initio force calls. We expect that this approach and future refinements will greatly accelerate searches for saddle points, as well as other searches on the potential energy surface, as machine-learning methods see greater adoption by the atomistics community.

  4. Acceleration of saddle-point searches with machine learning.

    Science.gov (United States)

    Peterson, Andrew A

    2016-08-21

    In atomistic simulations, the location of the saddle point on the potential-energy surface (PES) gives important information on transitions between local minima, for example, via transition-state theory. However, the search for saddle points often involves hundreds or thousands of ab initio force calls, which are typically all done at full accuracy. This results in the vast majority of the computational effort being spent calculating the electronic structure of states not important to the researcher, and very little time performing the calculation of the saddle point state itself. In this work, we describe how machine learning (ML) can reduce the number of intermediate ab initio calculations needed to locate saddle points. Since machine-learning models can learn from, and thus mimic, atomistic simulations, the saddle-point search can be conducted rapidly in the machine-learning representation. The saddle-point prediction can then be verified by an ab initio calculation; if it is incorrect, this strategically has identified regions of the PES where the machine-learning representation has insufficient training data. When these training data are used to improve the machine-learning model, the estimates greatly improve. This approach can be systematized, and in two simple example problems we demonstrate a dramatic reduction in the number of ab initio force calls. We expect that this approach and future refinements will greatly accelerate searches for saddle points, as well as other searches on the potential energy surface, as machine-learning methods see greater adoption by the atomistics community.

  5. FABRICATION OF WINDOW SADDLES FOR NIF CRYOGENIC HOHLRAUMS

    International Nuclear Information System (INIS)

    GIRALDEZ, E; KAAE, J.L

    2003-09-01

    OAK-B135 A planar diagnostic viewing port attached to the cylindrical wall of the NIF cryogenic hohlraum requires a saddle-like transition piece. While the basic design of this window saddle is straightforward, its fabrication is not, given the scale and precision of the component. They solved the problem through the use of a two segment copper mandrel to electroform the gold window saddle. The segments were micro-machined using a combination of single-point diamond turning and single point diamond milling. These processes as well as the electroplating conditions, final machining and mandrel removal are described in this paper

  6. Divided Saddle Theory: A New Idea for Rate Constant Calculation.

    Science.gov (United States)

    Daru, János; Stirling, András

    2014-03-11

    We present a theory of rare events and derive an algorithm to obtain rates from postprocessing the numerical data of a free energy calculation and the corresponding committor analysis. The formalism is based on the division of the saddle region of the free energy profile of the rare event into two adjacent segments called saddle domains. The method is built on sampling the dynamics within these regions: auxiliary rate constants are defined for the saddle domains and the absolute forward and backward rates are obtained by proper reweighting. We call our approach divided saddle theory (DST). An important advantage of our approach is that it requires only standard computational techniques which are available in most molecular dynamics codes. We demonstrate the potential of DST numerically on two examples: rearrangement of alanine-dipeptide (CH3CO-Ala-NHCH3) conformers and the intramolecular Cope reaction of the fluxional barbaralane molecule.

  7. Time delays across saddles as a test of modified gravity

    International Nuclear Information System (INIS)

    Magueijo, João; Mozaffari, Ali

    2013-01-01

    Modified gravity theories can produce strong signals in the vicinity of the saddles of the total gravitational potential. In a sub-class of these models, this translates into diverging time delays for echoes crossing the saddles. Such models arise from the possibility that gravity might be infrared divergent or confined, and if suitably designed they are very difficult to rule out. We show that Lunar Laser Ranging during an eclipse could probe the time-delay effect within metres of the saddle, thereby proving or excluding these models. Very Large Baseline Interferometry, instead, could target delays across the Jupiter–Sun saddle. Such experiments would shed light on the infrared behaviour of gravity and examine the puzzling possibility that there might be well-hidden regions of strong gravity and even singularities inside the solar system. (fast track communication)

  8. Natural Preconditioning and Iterative Methods for Saddle Point Systems

    KAUST Repository

    Pestana, Jennifer; Wathen, Andrew J.

    2015-01-01

    or the discrete setting, so saddle point systems arising from the discretization of partial differential equation problems, such as those describing electromagnetic problems or incompressible flow, lead to equations with this structure, as do, for example

  9. Complex saddle points in QCD at finite temperature and density

    Science.gov (United States)

    Nishimura, Hiromichi; Ogilvie, Michael C.; Pangeni, Kamal

    2014-08-01

    The sign problem in QCD at finite temperature and density leads naturally to the consideration of complex saddle points of the action or effective action. The global symmetry CK of the finite-density action, where C is charge conjugation and K is complex conjugation, constrains the eigenvalues of the Polyakov loop operator P at a saddle point in such a way that the action is real at a saddle point, and net color charge is zero. The values of TrFP and TrFP† at the saddle point are real but not identical, indicating the different free energy cost associated with inserting a heavy quark versus an antiquark into the system. At such complex saddle points, the mass matrix associated with Polyakov loops may have complex eigenvalues, reflecting oscillatory behavior in color-charge densities. We illustrate these properties with a simple model which includes the one-loop contribution of gluons and two flavors of massless quarks moving in a constant Polyakov loop background. Confinement-deconfinement effects are modeled phenomenologically via an added potential term depending on the Polyakov loop eigenvalues. For sufficiently large temperature T and quark chemical potential μ, the results obtained reduce to those of perturbation theory at the complex saddle point. These results may be experimentally relevant for the compressed baryonic matter experiment at FAIR.

  10. Experimental halls workshop summary

    International Nuclear Information System (INIS)

    Thorndike, A.

    1976-01-01

    A brief discussion is given of: (1) pros and cons of open areas as compared with enclosed halls; (2) experimental hall needs of ep, anti p p, and other options; (3) hall for the lepton detector; and, (4) hall for the hadron spectrometer

  11. Experimental halls workshop summary

    International Nuclear Information System (INIS)

    Thorndike, A.

    1976-01-01

    On May 26 and 27, 1976, approximately 50 people met for an informal workshop on plans for experimental halls for ISABELLE. Plans as they exist in the May 1976 version of the ISABELLE proposal were presented. Discussions were held on the following four general topics by separate working groups: (1) pros and cons of open areas as compared with enclosed halls; (2) experimental hall needs of ep, anti pp, and other options; (3) hall for the lepton detector; and (4) hall for the hadron spectrometer. The planning for experimental halls at PEP, the hall for the lepton detector, the hadron spectrometer, and open areas are discussed

  12. Experimental halls workshop summary

    International Nuclear Information System (INIS)

    Thorndike, A.

    1976-01-01

    At the experimental halls workshop, discussions were held on: (1) open areas as compared with enclosed halls; (2) the needs of ep, anti pp, and other options; (3) the hall for the lepton detector; and (4) the hall for the hadron spectrometer. The value of different possibilities for the future experimental program was explored. A number of suggestions emerged which will be used as the design of the experimental halls progresses

  13. Chaotic saddles in nonlinear modulational interactions in a plasma

    International Nuclear Information System (INIS)

    Miranda, Rodrigo A.; Rempel, Erico L.; Chian, Abraham C.-L.

    2012-01-01

    A nonlinear model of modulational processes in the subsonic regime involving a linearly unstable wave and two linearly damped waves with different damping rates in a plasma is studied numerically. We compute the maximum Lyapunov exponent as a function of the damping rates in a two-parameter space, and identify shrimp-shaped self-similar structures in the parameter space. By varying the damping rate of the low-frequency wave, we construct bifurcation diagrams and focus on a saddle-node bifurcation and an interior crisis associated with a periodic window. We detect chaotic saddles and their stable and unstable manifolds, and demonstrate how the connection between two chaotic saddles via coupling unstable periodic orbits can result in a crisis-induced intermittency. The relevance of this work for the understanding of modulational processes observed in plasmas and fluids is discussed.

  14. MIT-Skywalker: Evaluating comfort of bicycle/saddle seat.

    Science.gov (United States)

    Goncalves, Rogerio S; Hamilton, Taya; Daher, Ali R; Hirai, Hiroaki; Krebs, Hermano I

    2017-07-01

    The MIT-Skywalker is a robotic device developed for the rehabilitation of gait and balance after a neurological injury. This device has been designed based on the concept of a passive walker and provides three distinct training modes: discrete movement, rhythmic movement, and balance training. In this paper, we present our efforts to evaluate the comfort of a bicycle/saddle seat design for the system's novel actuated body weight support device. We employed different bicycle and saddle seats and evaluated comfort using objective and subjective measures. Here we will summarize the results obtained from a study of fifteen healthy subjects and one stroke patient that led to the selection of a saddle seat design for the MIT-Skywalker.

  15. Chaotic saddles in nonlinear modulational interactions in a plasma

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Rodrigo A. [Institute of Aeronautical Technology (ITA) and World Institute for Space Environment Research (WISER), Sao Jose dos Campos, SP 12228-900 (Brazil); National Institute for Space Research (INPE) and World Institute for Space Environment Research (WISER), P.O. Box 515, Sao Jose dos Campos, SP 12227-010 (Brazil); University of Brasilia (UnB), Gama Campus, and Plasma Physics Laboratory, Institute of Physics, Brasilia, DF 70910-900 (Brazil); Rempel, Erico L. [Institute of Aeronautical Technology (ITA) and World Institute for Space Environment Research (WISER), Sao Jose dos Campos, SP 12228-900 (Brazil); National Institute for Space Research (INPE) and World Institute for Space Environment Research (WISER), P.O. Box 515, Sao Jose dos Campos, SP 12227-010 (Brazil); Chian, Abraham C.-L. [Institute of Aeronautical Technology (ITA) and World Institute for Space Environment Research (WISER), Sao Jose dos Campos, SP 12228-900 (Brazil); National Institute for Space Research (INPE) and World Institute for Space Environment Research (WISER), P.O. Box 515, Sao Jose dos Campos, SP 12227-010 (Brazil); Observatoire de Paris, LESIA, CNRS, 92195 Meudon (France)

    2012-11-15

    A nonlinear model of modulational processes in the subsonic regime involving a linearly unstable wave and two linearly damped waves with different damping rates in a plasma is studied numerically. We compute the maximum Lyapunov exponent as a function of the damping rates in a two-parameter space, and identify shrimp-shaped self-similar structures in the parameter space. By varying the damping rate of the low-frequency wave, we construct bifurcation diagrams and focus on a saddle-node bifurcation and an interior crisis associated with a periodic window. We detect chaotic saddles and their stable and unstable manifolds, and demonstrate how the connection between two chaotic saddles via coupling unstable periodic orbits can result in a crisis-induced intermittency. The relevance of this work for the understanding of modulational processes observed in plasmas and fluids is discussed.

  16. Developments of saddle field ion sources and their applications

    International Nuclear Information System (INIS)

    Abdelrahman, M.M.; Helal, A.G.

    2009-01-01

    Ion sources should have different performance parameters according to the various applications for which they are used, ranging from ion beam production to high energy ion implanters. There are many kinds of ion sources, which produce different ion beams with different characteristics. This paper deals with the developments and applications of some saddle field ion sources which were designed and constructed in our lab. Theory of operation and types of saddle field ion sources are discussed in details. Some experimental results are given. The saddle field ion sources operate at low gas pressure and require neither magnetic field nor filament. This type of ion sources is used for many different applications as ion beam machining, sputtering, cleaning and profiling for surface analysis etc

  17. Natural Preconditioning and Iterative Methods for Saddle Point Systems

    KAUST Repository

    Pestana, Jennifer

    2015-01-01

    © 2015 Society for Industrial and Applied Mathematics. The solution of quadratic or locally quadratic extremum problems subject to linear(ized) constraints gives rise to linear systems in saddle point form. This is true whether in the continuous or the discrete setting, so saddle point systems arising from the discretization of partial differential equation problems, such as those describing electromagnetic problems or incompressible flow, lead to equations with this structure, as do, for example, interior point methods and the sequential quadratic programming approach to nonlinear optimization. This survey concerns iterative solution methods for these problems and, in particular, shows how the problem formulation leads to natural preconditioners which guarantee a fast rate of convergence of the relevant iterative methods. These preconditioners are related to the original extremum problem and their effectiveness - in terms of rapidity of convergence - is established here via a proof of general bounds on the eigenvalues of the preconditioned saddle point matrix on which iteration convergence depends.

  18. DETECTING ALIEN LIMIT CYCLES NEAR A HAMILTONIAN 2-SADDLE CYCLE

    OpenAIRE

    LUCA, Stijn; DUMORTIER, Freddy; Caubergh, M.; Roussarie, R.

    2009-01-01

    This paper aims at providing and example of a cubic Hamiltonian 2-saddle cycle that after bifurcation can give rise to an alien limit cycle; this is a limit cycle that is not controlled by a zero of the related Abelian integral. To guarantee the existence of an alien limit cycle one can verify generic conditions on the Abelian integral and on the transition map associated to the connections of the 2-saddle cycle. In this paper, a general method is developed to compute the first and second der...

  19. Evaluation of saddle and driving aptitudes in Monterufoli pony

    Directory of Open Access Journals (Sweden)

    Riccardo Bozzi

    2010-01-01

    Full Text Available The Monterufoli pony is an endangered Tuscan breed. In the 80’s began a project for the conservation of the breed and at present there are roughly 200 individuals. The equine was once utilized for saddle and driving and this study deals with the training for these two aptitudes. The mor- phologic type of the pony seems suited for saddle, in particular for children and beginners, and driving. The ponies showed developed chest, strong legs with short shanks: all these characters were useful for trot and driving. In this trial 3-4 years old never tamed Monterufoli ponies were opportunely choose and subsequently trained for saddle and driving. The ponies were submitted to the “aptitude test” for the two aptitudes and the results were good both for practical and character sides. The marks for sad- dle and driving were 8.16 and 8.06 respectively. Also the 3 ponies showed good results for the Aptitude Index: 7.60, 7.87 and 7.89. The results of the trial showed the excellent ability of the Monterufoli pony for saddle and driving. The good results of the test are important for the diffusion of the breed in the territory and in particular in horse centres and in equestrian tourism sites.

  20. Electrons at the monkey saddle: A multicritical Lifshitz point

    Science.gov (United States)

    Shtyk, A.; Goldstein, G.; Chamon, C.

    2017-01-01

    We consider two-dimensional interacting electrons at a monkey saddle with dispersion ∝px3-3 pxpy2 . Such a dispersion naturally arises at the multicritical Lifshitz point when three Van Hove saddles merge in an elliptical umbilic elementary catastrophe, which we show can be realized in biased bilayer graphene. A multicritical Lifshitz point of this kind can be identified by its signature Landau level behavior Em∝(Bm ) 3 /2 and related oscillations in thermodynamic and transport properties, such as de Haas-Van Alphen and Shubnikov-de Haas oscillations, whose period triples as the system crosses the singularity. We show, in the case of a single monkey saddle, that the noninteracting electron fixed point is unstable to interactions under the renormalization-group flow, developing either a superconducting instability or non-Fermi-liquid features. Biased bilayer graphene, where there are two non-nested monkey saddles at the K and K' points, exhibits an interplay of competing many-body instabilities, namely, s -wave superconductivity, ferromagnetism, and spin- and charge-density waves.

  1. 19 CFR 148.32 - Vehicles, aircraft, boats, teams and saddle horses taken abroad.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Vehicles, aircraft, boats, teams and saddle horses... for Returning Residents § 148.32 Vehicles, aircraft, boats, teams and saddle horses taken abroad. (a) Admission free of duty. Automobiles and other vehicles, aircraft, boats, teams and saddle horses, together...

  2. Effect of Anode Magnetic Shield on Magnetic Field and Ion Beam in Cylindrical Hall Thruster

    International Nuclear Information System (INIS)

    Zhao Jie; Wang Shiqing; Liu Jian; Xu Li; Tang Deli; Geng Shaofei

    2010-01-01

    Numerical simulation of the effect of the anode magnetic shielding on the magnetic field and ion beam in a cylindrical Hall thruster is presented. The results show that after the anode is shielded by the magnetic shield, the magnetic field lines near the anode surface are obviously convex curved, the ratio of the magnetic mirror is enhanced, the width of the positive magnetic field gradient becomes larger than that without the anode magnetic shielding, the radial magnetic field component is enhanced, and the discharge plasma turbulence is reduced as a result of keeping the original saddle field profile and the important role the other two saddle field profiles play in restricting electrons. The results of the particle in cell (PIC) numerical simulation show that both the ion number and the energy of the ion beam increase after the anode is shielded by the magnetic shield. In other words, the specific impulse of the cylindrical Hall thruster is enhanced.

  3. Surface plasma source with saddle antenna radio frequency plasma generator.

    Science.gov (United States)

    Dudnikov, V; Johnson, R P; Murray, S; Pennisi, T; Piller, C; Santana, M; Stockli, M; Welton, R

    2012-02-01

    A prototype RF H(-) surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA∕kW. Control experiments with H(-) beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.

  4. Cryogenic microsize Hall sensors

    International Nuclear Information System (INIS)

    Kvitkovic, J.; Polak, M.

    1993-01-01

    Hall sensors have a variety of applications in magnetic field measurements. The active area of the Hall sensor does not play an important role in measuring of homogeneous magnetic field. Actually Hall sensors are widely used to measure profiles of magnetic fields produced by magnetization currents in samples of HTC superconductors, as well as of LTC ones. Similar techniques are used to measure magnetization of both HTC and LTC superconductors. In these cases Hall sensor operates in highly inhomogeneous magnetic fields. Because of that, Hall sensors with very small active area are required. We developed and tested Hall sensors with active area 100 μm x 100 μm - type M and 50 μm x 50 μm - type V. Here we report on the most imporant parameters of these units, as well as on their properties as differential magnetometer. (orig.)

  5. Krylov Subspace Methods for Saddle Point Problems with Indefinite Preconditioning

    Czech Academy of Sciences Publication Activity Database

    Rozložník, Miroslav; Simoncini, V.

    2002-01-01

    Roč. 24, č. 2 (2002), s. 368-391 ISSN 0895-4798 R&D Projects: GA ČR GA101/00/1035; GA ČR GA201/00/0080 Institutional research plan: AV0Z1030915 Keywords : saddle point problems * preconditioning * indefinite linear systems * finite precision arithmetic * conjugate gradients Subject RIV: BA - General Mathematics Impact factor: 0.753, year: 2002

  6. Maximum Attainable Accuracy of Inexact Saddle Point Solvers

    Czech Academy of Sciences Publication Activity Database

    Jiránek, P.; Rozložník, Miroslav

    2008-01-01

    Roč. 29, č. 4 (2008), s. 1297-1321 ISSN 0895-4798 R&D Projects: GA MŠk 1M0554; GA AV ČR 1ET400300415 Institutional research plan: CEZ:AV0Z10300504 Keywords : saddle point problems * Schur complement reduction * null-space projection method * rounding error analysis Subject RIV: BA - General Mathematics Impact factor: 1.328, year: 2008

  7. Unified analysis of preconditioning methods for saddle point matrices

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe

    2015-01-01

    Roč. 22, č. 2 (2015), s. 233-253 ISSN 1070-5325 R&D Projects: GA MŠk ED1.1.00/02.0070 Institutional support: RVO:68145535 Keywords : saddle point problems * preconditioning * spectral properties Subject RIV: BA - General Mathematics Impact factor: 1.431, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/nla.1947/pdf

  8. Regularization of the Boundary-Saddle-Node Bifurcation

    Directory of Open Access Journals (Sweden)

    Xia Liu

    2018-01-01

    Full Text Available In this paper we treat a particular class of planar Filippov systems which consist of two smooth systems that are separated by a discontinuity boundary. In such systems one vector field undergoes a saddle-node bifurcation while the other vector field is transversal to the boundary. The boundary-saddle-node (BSN bifurcation occurs at a critical value when the saddle-node point is located on the discontinuity boundary. We derive a local topological normal form for the BSN bifurcation and study its local dynamics by applying the classical Filippov’s convex method and a novel regularization approach. In fact, by the regularization approach a given Filippov system is approximated by a piecewise-smooth continuous system. Moreover, the regularization process produces a singular perturbation problem where the original discontinuous set becomes a center manifold. Thus, the regularization enables us to make use of the established theories for continuous systems and slow-fast systems to study the local behavior around the BSN bifurcation.

  9. Skyrmions and Hall viscosity

    Science.gov (United States)

    Kim, Bom Soo

    2018-05-01

    We discuss the contribution of magnetic Skyrmions to the Hall viscosity and propose a simple way to identify it in experiments. The topological Skyrmion charge density has a distinct signature in the electric Hall conductivity that is identified in existing experimental data. In an electrically neutral system, the Skyrmion charge density is directly related to the thermal Hall conductivity. These results are direct consequences of the field theory Ward identities, which relate various physical quantities based on symmetries and have been previously applied to quantum Hall systems.

  10. Large N saddle formulation of quadratic building block theories

    International Nuclear Information System (INIS)

    Halpern, M.B.

    1980-01-01

    I develop a large N saddle point formulation for the broad class of 'theories of quadratic building blocks'. Such theories are those on which the sums over internal indices are contained in quadratic building blocks, e.g. PHI 2 = Σsup(N)sub(a-1)PHi sup(a)sup(a). The formulation applies as well to fermions, derivative coupling and non-polynomial interactions. In a related development, closed Schwinger-Dyson equations for Green functions of the building blocks are derived and solved for large N. (orig.)

  11. Computation of saddle-type slow manifolds using iterative methods

    DEFF Research Database (Denmark)

    Kristiansen, Kristian Uldall

    2015-01-01

    with respect to , appropriate estimates are directly attainable using the method of this paper. The method is applied to several examples, including a model for a pair of neurons coupled by reciprocal inhibition with two slow and two fast variables, and the computation of homoclinic connections in the Fitz......This paper presents an alternative approach for the computation of trajectory segments on slow manifolds of saddle type. This approach is based on iterative methods rather than collocation-type methods. Compared to collocation methods, which require mesh refinements to ensure uniform convergence...

  12. Recent progress in fission at saddle point and scission point

    International Nuclear Information System (INIS)

    Blons, J.; Paya, D.; Signarbieux, C.

    High resolution measurements of 230 Th and 232 Th fission cross sections for neutrons exhibit a fine structure. Such a structure is interpreted as a superposition of two rotational bands in the third, asymmetric, well of the fission barrier. The fragment mass distribution in the thermal fission of 235 U and 233 U does not show any even-odd effect, even at the highest kinetic energies. This is the mark of a strong viscosity in the descent from saddle point to scission point [fr

  13. Saddle-points of a two dimensional random lattice theory

    International Nuclear Information System (INIS)

    Pertermann, D.

    1985-07-01

    A two dimensional random lattice theory with a free massless scalar field is considered. We analyse the field theoretic generating functional for any given choice of positions of the lattice sites. Asking for saddle-points of this generating functional with respect to the positions we find the hexagonal lattice and a triangulated version of the hypercubic lattice as candidates. The investigation of the neighbourhood of a single lattice site yields triangulated rectangles and regular polygons extremizing the above generating functional on the local level. (author)

  14. Triangular preconditioners for saddle point problems with a penalty term

    Energy Technology Data Exchange (ETDEWEB)

    Klawonn, A. [Westfaelische Wilhelms-Universitaet, Muenster (Germany)

    1996-12-31

    Triangular preconditioners for a class of saddle point problems with a penalty term are considered. An important example is the mixed formulation of the pure displacement problem in linear elasticity. It is shown that the spectrum of the preconditioned system is contained in a real, positive interval, and that the interval bounds can be made independent of the discretization and penalty parameters. This fact is used to construct bounds of the convergence rate of the GMRES method used with an energy norm. Numerical results are given for GMRES and BI-CGSTAB.

  15. The effect of saddle design on stresses in the perineum during cycling.

    Science.gov (United States)

    Spears, Iain R; Cummins, Neil K; Brenchley, Zoe; Donohue, Claire; Turnbull, Carli; Burton, Shona; Macho, Gabrielle A

    2003-09-01

    Repetitive internal stress in the perineum has been associated with soft-tissue trauma in bicyclists. Using an engineering approach, the purpose of this study was to quantify the amount of compression exerted in the perineum for a range of saddle widths and orientations. Computer tomography was used to create a three-dimensional voxel-based finite element model of the right side of the male perineum-pelvis. For the creation of the saddle model, a commercially available saddle was digitized and the surface manipulated to represent a variety of saddle widths and orientations. The two models were merged, and a static downward load of 189 N was applied to the model at the region representing the sacroiliac joint. For validation purposes, external stresses along the perineum-saddle interface were compared with the results of pressure sensitive film. Good agreement was found for these external stresses. The saddles were then stretched and rotated, and the magnitude and location of maximum stresses within the perineum were both recorded. In all cases, the model of the pelvis-perineum was held in an upright position. Stresses within the perineum were reduced when the saddle was sufficiently wide to support both ischial tuberosities. This supporting mechanism was best achieved when the saddle was at least two times wider than the bi-ischial width of the cyclist. Stresses in the anterior of the perineum were reduced when the saddle was tilted downward, whereas stresses in the posterior were reduced when the saddle was tilted upward. Recommendations that saddles should be sufficiently wide to support the ischial tuberosities appear to be well founded. Recommendations that saddles be tilted downward (i.e., nose down) are supported by the model, but with caution, given the limitations of the model.

  16. Effect of bicycle saddle designs on the pressure to the perineum of the bicyclist.

    Science.gov (United States)

    Lowe, Brian D; Schrader, Steven M; Breitenstein, Michael J

    2004-06-01

    Increasing awareness of an association between bicycling and male sexual dysfunction has led to the appearance of a variety of bicycle saddles that share the design objective of reducing pressure in the groin of the cyclist by removal of the narrow protruding nose of the saddle. This study compared three of these saddle designs to a traditional sport/road racing saddle with a narrow protruding nose in terms of pressure in the region of the perineum (groin) of the cyclist. Saddle, pedal, and handlebar contact pressure were measured from 33 bicycle police patrol officers pedaling a stationary bicycle at a controlled cadence and workload. Pressure was characterized over the saddle as a whole and over a region of the saddle assumed to represent pressure on the cyclist's perineum located anteriorly to the ischial tuberosities. The traditional sport/racing saddle was associated with more than two times the pressure in the perineal region than the saddles without a protruding nose (P perineum of the bicyclist.

  17. Feature-Based Retinal Image Registration Using D-Saddle Feature

    Directory of Open Access Journals (Sweden)

    Roziana Ramli

    2017-01-01

    Full Text Available Retinal image registration is important to assist diagnosis and monitor retinal diseases, such as diabetic retinopathy and glaucoma. However, registering retinal images for various registration applications requires the detection and distribution of feature points on the low-quality region that consists of vessels of varying contrast and sizes. A recent feature detector known as Saddle detects feature points on vessels that are poorly distributed and densely positioned on strong contrast vessels. Therefore, we propose a multiresolution difference of Gaussian pyramid with Saddle detector (D-Saddle to detect feature points on the low-quality region that consists of vessels with varying contrast and sizes. D-Saddle is tested on Fundus Image Registration (FIRE Dataset that consists of 134 retinal image pairs. Experimental results show that D-Saddle successfully registered 43% of retinal image pairs with average registration accuracy of 2.329 pixels while a lower success rate is observed in other four state-of-the-art retinal image registration methods GDB-ICP (28%, Harris-PIIFD (4%, H-M (16%, and Saddle (16%. Furthermore, the registration accuracy of D-Saddle has the weakest correlation (Spearman with the intensity uniformity metric among all methods. Finally, the paired t-test shows that D-Saddle significantly improved the overall registration accuracy of the original Saddle.

  18. Optimization of saddle coils for magnetic resonance imaging

    International Nuclear Information System (INIS)

    Salmon, Carlos Ernesto Garrido; Vidoto, Edson Luiz Gea; Martins, Mateus Jose; Tannus, Alberto

    2006-01-01

    In Nuclear Magnetic Resonance (NMR) experiments, besides the apparatus designed to acquire the NMR signal, it is necessary to generate a radio frequency electromagnetic field using a device capable to transduce electromagnetic power into a transverse magnetic field. We must generate this transverse homogeneous magnetic field inside the region of interest with minimum power consumption. Many configurations have been proposed for this task, from coils to resonators. For low field intensity (<0.5 T) and small sample dimensions (<30 cm), the saddle coil configuration has been widely used. In this work we present a simplified method for calculating the magnetic field distribution in these coils considering the current density profile. We propose an optimized saddle configuration as a function of the dimensions of the region of interest, taking into account the uniformity and the sensitivity. In order to evaluate the magnetic field uniformity three quantities have been analyzed: Non-uniformity, peak-to-peak homogeneity and relative uniformity. Some experimental results are presented to validate our calculation. (author)

  19. Power inverter design for ASDEX Upgrade saddle coils

    Energy Technology Data Exchange (ETDEWEB)

    Teschke, M., E-mail: teschke@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Suttrop, W.; Rott, M. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2013-10-15

    Highlights: ► A cost effective inverter topology for AUG's 16 in-vessel saddle coils has been found. ► Use of commercially available power modules is possible. ► Exchange of reactive power between multiple inverters is possible. ► Influence of electromagnetic noise to AUG's diagnostics was measured. ► Gas insulation of electric feed through significantly depends on magnetic fields. It is protected by fast turn-off circuit. -- Abstract: A set of 16 in-vessel saddle coils has been installed in the ASDEX Upgrade (AUG) experiment since the end of 2011 [1]. To achieve full performance, it is necessary to operate them with alternating current (AC) of arbitrary waveforms. To generate spatially resolved magnetic fields, it is required to allocate separate power inverters to every single coil. Therefore, different topologies are analyzed and compared. Studies of the commutation behavior of power stages, different pulse width modulation (PWM) schemes and single-phase-to-earth fault detection are executed. Experiments to evaluate the electromagnetic interference (EMI) of possible inverter topologies on the AUG diagnostics are done as well. A special focus is put on the feasibility of analyzed topologies using industrially available and fully assembled “power modules” to minimize development effort and costs.

  20. Halls Lake 1990

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Salt marsh habitats along the shoreline of Halls Lake are threatened by wave erosion, but the reconstruction of barrier islands to reduce this erosion will modify or...

  1. The quantum hall effect

    International Nuclear Information System (INIS)

    El-Arabi, N. M.

    1993-01-01

    Transport phenomena in two dimensional semiconductors have revealed unusual properties. In this thesis these systems are considered and discussed. The theories explain the Integral Quantum Hall Effect (IQHE) and the Fractional Quantum Hall Effect (FQHE). The thesis is composed of five chapters. The first and the second chapters lay down the theory of the IQHE, the third and fourth consider the theory of the FQHE. Chapter five deals with the statistics of particles in two dimension. (author). Refs

  2. Hall viscosity of hierarchical quantum Hall states

    Science.gov (United States)

    Fremling, M.; Hansson, T. H.; Suorsa, J.

    2014-03-01

    Using methods based on conformal field theory, we construct model wave functions on a torus with arbitrary flat metric for all chiral states in the abelian quantum Hall hierarchy. These functions have no variational parameters, and they transform under the modular group in the same way as the multicomponent generalizations of the Laughlin wave functions. Assuming the absence of Berry phases upon adiabatic variations of the modular parameter τ, we calculate the quantum Hall viscosity and find it to be in agreement with the formula, given by Read, which relates the viscosity to the average orbital spin of the electrons. For the filling factor ν =2/5 Jain state, which is at the second level in the hierarchy, we compare our model wave function with the numerically obtained ground state of the Coulomb interaction Hamiltonian in the lowest Landau level, and find very good agreement in a large region of the complex τ plane. For the same example, we also numerically compute the Hall viscosity and find good agreement with the analytical result for both the model wave function and the numerically obtained Coulomb wave function. We argue that this supports the notion of a generalized plasma analogy that would ensure that wave functions obtained using the conformal field theory methods do not acquire Berry phases upon adiabatic evolution.

  3. Hall probe for measuring high currents in superconducting coils

    International Nuclear Information System (INIS)

    Ferendeci, A.M.

    1986-01-01

    Constructional details of a compact Hall probe for measuring high currents in superconducting coils are given. The Hall probe is easy to assemble and can be inserted or removed from the system without breaking the superconducting loop. Upper current limit of the probe can be increased by using larger magnetic core material. Shielding becomes necessary if the probe holder is to be placed near large current dependent magnetic fields

  4. The Sun-Earth saddle point: characterization and opportunities to test general relativity

    Science.gov (United States)

    Topputo, Francesco; Dei Tos, Diogene A.; Rasotto, Mirco; Nakamiya, Masaki

    2018-04-01

    The saddle points are locations where the net gravitational accelerations balance. These regions are gathering more attention within the astrophysics community. Regions about the saddle points present clean, close-to-zero background acceleration environments where possible deviations from General Relativity can be tested and quantified. Their location suggests that flying through a saddle point can be accomplished by leveraging highly nonlinear orbits. In this paper, the geometrical and dynamical properties of the Sun-Earth saddle point are characterized. A systematic approach is devised to find ballistic orbits that experience one or multiple passages through this point. A parametric analysis is performed to consider spacecraft initially on L_{1,2} Lagrange point orbits. Sun-Earth saddle point ballistic fly-through trajectories are evaluated and classified for potential use. Results indicate an abundance of short-duration, regular solutions with a variety of characteristics.

  5. Using a new saddle model for echinotherapy therapy.

    Directory of Open Access Journals (Sweden)

    Carlos Cesar Santín Alfaro

    2014-09-01

    Full Text Available A descriptive study with experimental design was done, having as an objective to elaborate a new riding saddle model in the Provincial Laboratory of Technical Orthopaedics in the province of Sancti Spiritus for the Echinotherapy´s treatment in disable patients that still assisting to this kind of alternative therapy having the necessity of obtaining the frame according to the adequate characteristics and adjusting to the requirements of the qualified staff that takes care of this task taking into consideration that for the rehabilitation of these children they should be closer to the horse skin. The frame was not made with the row materials of normal chair but with the one adequate in our Laboratory. Some important characteristics were developed in this kind of therapy, and was analyzed the characteristics of the frame use give to patients, offering an immediate solution to their problems in order to solve this difficulty in our province.

  6. Saddle point solutions in Yang-Mills-dilaton theory

    International Nuclear Information System (INIS)

    Bizon, P.

    1992-01-01

    The coupling of a dilaton to the SU(2)-Yang-Mills field leads to interesting non-perturbative static spherically symmetric solutions which are studied by mixed analytical and numerical methods. In the abelian sector of the theory there are finite-energy magnetic and electric monopole solutions which saturate the Bogomol'nyi bound. In the nonabelian sector there exist a countable family of globally regular solutions which are purely magnetic but have zero Yang-Mills magnetic charge. Their discrete spectrum of energies is bounded from above by the energy of the abelian magnetic monopole with unit magnetic charge. The stability analysis demonstrates that the solutions are saddle points of the energy functional with increasing number of unstable modes. The existence and instability of these solutions are 'explained' by the Morse-theory argument recently proposed by Sudarsky and Wald. (author)

  7. On the many saddle points description of quantum black holes

    Energy Technology Data Exchange (ETDEWEB)

    Germani, Cristiano, E-mail: cristiano.germani@physik.uni-muenchen.de

    2014-06-02

    Considering two dimensional gravity coupled to a CFT, we show that a semiclassical black hole can be described in terms of two Liouville theories matched at the horizon. The black hole exterior corresponds to a space-like while the interior to a time-like Liouville theory. This matching automatically implies that a semiclassical black hole has an infinite entropy. The path integral description of the time-like Liouville theory (the Black Hole interior) is studied and it is found that the correlation functions of the coupled CFT-gravity system are dominated by two (complex) saddle points, even in the semiclassical limit. We argue that this system can be interpreted as two interacting Bose–Einstein condensates constructed out of two degenerate quantum states. In AdS/CFT context, the same system is mapped into two interacting strings intersecting inside a three-dimensional BTZ black hole.

  8. Hamiltonian flow over saddles for exploring molecular phase space structures

    Science.gov (United States)

    Farantos, Stavros C.

    2018-03-01

    Despite using potential energy surfaces, multivariable functions on molecular configuration space, to comprehend chemical dynamics for decades, the real happenings in molecules occur in phase space, in which the states of a classical dynamical system are completely determined by the coordinates and their conjugate momenta. Theoretical and numerical results are presented, employing alanine dipeptide as a model system, to support the view that geometrical structures in phase space dictate the dynamics of molecules, the fingerprints of which are traced by following the Hamiltonian flow above saddles. By properly selecting initial conditions in alanine dipeptide, we have found internally free rotor trajectories the existence of which can only be justified in a phase space perspective. This article is part of the theme issue `Modern theoretical chemistry'.

  9. The quantized Hall effect

    International Nuclear Information System (INIS)

    Klitzing von, K.

    1989-01-01

    The quantized Hall effect is theoretically explained in detail as are its basic properties. The explanation is completed with the pertinent mathematical relations and illustrative figures. Experimental data are critically assessed obtained by quantum transport measurement in a magnetic field on two-dimensional systems. The results are reported for a MOSFET silicon transistor and for GaAs-Al x Ga 1-x As heterostructures. The application is discussed of the quantized Hall effect in determining the fine structure constant or in implementing the resistance standard. (M.D.). 27 figs., 57 refs

  10. Intrinsic superspin Hall current

    Science.gov (United States)

    Linder, Jacob; Amundsen, Morten; Risinggârd, Vetle

    2017-09-01

    We discover an intrinsic superspin Hall current: an injected charge supercurrent in a Josephson junction containing heavy normal metals and a ferromagnet generates a transverse spin supercurrent. There is no accompanying dissipation of energy, in contrast to the conventional spin Hall effect. The physical origin of the effect is an antisymmetric spin density induced among transverse modes ky near the interface of the superconductor arising due to the coexistence of p -wave and conventional s -wave superconducting correlations with a belonging phase mismatch. Our predictions can be tested in hybrid structures including thin heavy metal layers combined with strong ferromagnets and ordinary s -wave superconductors.

  11. Hall effect in hopping regime

    International Nuclear Information System (INIS)

    Avdonin, A.; Skupiński, P.; Grasza, K.

    2016-01-01

    A simple description of the Hall effect in the hopping regime of conductivity in semiconductors is presented. Expressions for the Hall coefficient and Hall mobility are derived by considering averaged equilibrium electron transport in a single triangle of localization sites in a magnetic field. Dependence of the Hall coefficient is analyzed in a wide range of temperature and magnetic field values. Our theoretical result is applied to our experimental data on temperature dependence of Hall effect and Hall mobility in ZnO. - Highlights: • Expressions for Hall coefficient and mobility for hopping conductivity are derived. • Theoretical result is compared with experimental curves measured on ZnO. • Simultaneous action of free and hopping conduction channels is considered. • Non-linearity of hopping Hall coefficient is predicted.

  12. Hall effect in hopping regime

    Energy Technology Data Exchange (ETDEWEB)

    Avdonin, A., E-mail: avdonin@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Skupiński, P. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Grasza, K. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Institute of Electronic Materials Technology, ul. Wólczyńska 133, 01-919 Warszawa (Poland)

    2016-02-15

    A simple description of the Hall effect in the hopping regime of conductivity in semiconductors is presented. Expressions for the Hall coefficient and Hall mobility are derived by considering averaged equilibrium electron transport in a single triangle of localization sites in a magnetic field. Dependence of the Hall coefficient is analyzed in a wide range of temperature and magnetic field values. Our theoretical result is applied to our experimental data on temperature dependence of Hall effect and Hall mobility in ZnO. - Highlights: • Expressions for Hall coefficient and mobility for hopping conductivity are derived. • Theoretical result is compared with experimental curves measured on ZnO. • Simultaneous action of free and hopping conduction channels is considered. • Non-linearity of hopping Hall coefficient is predicted.

  13. Measuring the distance from saddle points and driving to locate them over quantum control landscapes

    International Nuclear Information System (INIS)

    Sun, Qiuyang; Riviello, Gregory; Rabitz, Herschel; Wu, Re-Bing

    2015-01-01

    Optimal control of quantum phenomena involves the introduction of a cost functional J to characterize the degree of achieving a physical objective by a chosen shaped electromagnetic field. The cost functional dependence upon the control forms a control landscape. Two theoretically important canonical cases are the landscapes associated with seeking to achieve either a physical observable or a unitary transformation. Upon satisfaction of particular assumptions, both landscapes are analytically known to be trap-free, yet possess saddle points at precise suboptimal J values. The presence of saddles on the landscapes can influence the effort needed to find an optimal field. As a foundation to future algorithm development and analyzes, we define metrics that identify the ‘distance’ from a given saddle based on the sufficient and necessary conditions for the existence of the saddles. Algorithms are introduced utilizing the metrics to find a control such that the dynamics arrive at a targeted saddle. The saddle distance metric and saddle-seeking methodology is tested numerically in several model systems. (paper)

  14. The Monty Hall Dilemma.

    Science.gov (United States)

    Granberg, Donald; Brown, Thad A.

    1995-01-01

    Examines people's behavior in the Monty Hall Dilemma (MHD), in which a person must make two decisions to win a prize. In a series of five studies, found that people misapprehend probabilities in the MHD. Discusses the MHD's relation to illusion of control, belief perseverance, and the status quo bias. (RJM)

  15. The Isolde experimental hall

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    General view of the Isotope-Separator On-Line (ISOLDE) hall. ISOLDE is dedicated to the production of a large variety of radioactive ion beams for many different experiments. Rare isotopes can be produced allowing the study of spectra for neutrino beam production.

  16. Hall Sweet Home

    Science.gov (United States)

    Oguntoyinbo, Lekan

    2011-01-01

    Many urban and commuter universities have their sights set on students who are unlikely to connect with the college and likely to fail unless the right strategies are put in place to help them graduate. In efforts to improve retention rates, commuter colleges are looking to an unusual suspect: residence halls. The author discusses how these…

  17. Anomalous Hall effect

    Czech Academy of Sciences Publication Activity Database

    Nagaosa, N.; Sinova, Jairo; Onoda, S.; MacDonald, A. H.; Ong, N. P.

    2010-01-01

    Roč. 82, č. 2 (2010), s. 1539-1592 ISSN 0034-6861 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 51.695, year: 2010

  18. Laurance David Hall.

    Science.gov (United States)

    Coxon, Bruce

    2011-01-01

    An account is given of the life, scientific contributions, and passing of Laurance David Hall (1938-2009), including his early history and education at the University of Bristol, UK, and the synthesis and NMR spectroscopy of carbohydrates and other natural products during ∼20 years of research and teaching at the University of British Columbia in Vancouver, Canada. Lists of graduate students, post-doctoral fellows, and sabbatical visitors are provided for this period. Following a generous endowment by Dr. Herchel Smith, Professor Hall built a new Department of Medicinal Chemistry at Cambridge University, UK, and greatly expanded his researches into the technology and applications of magnetic resonance imaging (MRI) and zero quantum NMR. MRI technology was applied both to medical problems such as the characterization of cartilage degeneration in knee joints, the measurement of ventricular function, lipid localization in animal models of atherosclerosis, paramagnetic metal complexes of polysaccharides as contrast agents, and studies of many other anatomical features, but also to several aspects of materials analysis, including food analyses, process control, and the elucidation of such physical phenomena as the flow of liquids through porous media, defects in concrete, and the visualization of fungal damage to wood. Professor Hall's many publications, patents, lectures, and honors and awards are described, and also his successful effort to keep the Asilomar facility in Pacific Grove, California as the alternating venue for the annual Experimental NMR Conference. Two memorial services for Professor Hall are remembered. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Geology of the Saddle Mountains between Sentinel Gap and 119030' longitude

    International Nuclear Information System (INIS)

    Reidel, S.P.

    1978-09-01

    Members and flows of the Grande Ronde, Wanapum, and Saddle Mountains basalts of the Columbia River Basalt Group were mapped in the Saddle Mountains between Sentinel Gap and the eastern edge of Smyrna Bench. The Grande Ronde Basalt consists of the Schwana (low-MgO) and Sentinel Bluffs (high-MgO) members (informal names). The Wanapum Basalt consists of the aphyric and phyric units of the Frenchman Springs Member, the Roza-Like Member, and the Priest Rapids Member. The Saddle Mountains Basalt consists of the Wahluke, Huntzinger, Pomona, Mattawa, and Elephant Mountain basalts. The Wanapum and Saddle Mountains basalts are unevenly distributed across the Saddle Mountains. The Wanapum Basalt thins from south to north and across a northwest-southeast-trending axis at the west end of Smyrna Bench. The Priest Rapids, Roza-Like, and aphyric Frenchman Springs units are locally missing across this zone. The Saddle Mountains basalt has a more irregular distribution and, within an area between Sentinel Gap and Smyrna Bench, is devoid of the basalt. The Wahluke, Huntzinger, and Mattawa flows are locally present, but the Pomona is restricted to the southern flank west of Smyrna Bench, and the Elephant Mountain Basalt only occurs on the flanks and in three structurally controlled basins on the northwest side. The structure of the Saddle Mountains is dominated by an east-west trend and, to a lesser degree, controlled by a northwest-southeast and northeast-southwest trend. The geomorphological expression of the Saddle Mountains results from the east-west fold set and the Saddle Mountains fault along the north side. The oldest structures follow the northwest-southeast trend. The distribution of the flows, combined with the structural features, indicates a complex geologic history for the Saddel Mountains

  20. Identifying Septal Support Reconstructions for Saddle Nose Deformity: The Cakmak Algorithm.

    Science.gov (United States)

    Cakmak, Ozcan; Emre, Ismet Emrah; Ozkurt, Fazil Emre

    2015-01-01

    The saddle nose deformity is one of the most challenging problems in nasal surgery with a less predictable and reproducible result than other nasal procedures. The main feature of this deformity is loss of septal support with both functional and aesthetic implications. Most reports on saddle nose have focused on aesthetic improvement and neglected the reestablishment of septal support to improve airway. To explain how the Cakmak algorithm, an algorithm that describes various fixation techniques and grafts in different types of saddle nose deformities, aids in identifying saddle nose reconstructions that restore supportive nasal framework and provide the aesthetic improvements typically associated with procedures to correct saddle nose deformities. This algorithm presents septal support reconstruction of patients with saddle nose deformity based on the experience of the senior author in 206 patients with saddle nose deformity. Preoperative examination, intraoperative assessment, reconstruction techniques, graft materials, and patient evaluation of aesthetic success were documented, and 4 different types of saddle nose deformities were defined. The Cakmak algorithm classifies varying degrees of saddle nose deformity from type 0 to type 4 and helps identify the most appropriate surgical procedure to restore the supportive nasal framework and aesthetic dorsum. Among the 206 patients, 110 women and 96 men, mean (range) age was 39.7 years (15-68 years), and mean (range) of follow-up was 32 months (6-148 months). All but 12 patients had a history of previous nasal surgeries. Application of the Cakmak algorithm resulted in 36 patients categorized with type 0 saddle nose deformities; 79, type 1; 50, type 2; 20, type 3a; 7, type 3b; and 14, type 4. Postoperative photographs showed improvement of deformities, and patient surveys revealed aesthetic improvement in 201 patients and improvement in nasal breathing in 195 patients. Three patients developed postoperative infection

  1. Spin Hall effects

    Science.gov (United States)

    Sinova, Jairo; Valenzuela, Sergio O.; Wunderlich, J.; Back, C. H.; Jungwirth, T.

    2015-10-01

    Spin Hall effects are a collection of relativistic spin-orbit coupling phenomena in which electrical currents can generate transverse spin currents and vice versa. Despite being observed only a decade ago, these effects are already ubiquitous within spintronics, as standard spin-current generators and detectors. Here the theoretical and experimental results that have established this subfield of spintronics are reviewed. The focus is on the results that have converged to give us the current understanding of the phenomena, which has evolved from a qualitative to a more quantitative measurement of spin currents and their associated spin accumulation. Within the experimental framework, optical-, transport-, and magnetization-dynamics-based measurements are reviewed and linked to both phenomenological and microscopic theories of the effect. Within the theoretical framework, the basic mechanisms in both the extrinsic and intrinsic regimes are reviewed, which are linked to the mechanisms present in their closely related phenomenon in ferromagnets, the anomalous Hall effect. Also reviewed is the connection to the phenomenological treatment based on spin-diffusion equations applicable to certain regimes, as well as the spin-pumping theory of spin generation used in many measurements of the spin Hall angle. A further connection to the spin-current-generating spin Hall effect to the inverse spin galvanic effect is given, in which an electrical current induces a nonequilibrium spin polarization. This effect often accompanies the spin Hall effect since they share common microscopic origins. Both can exhibit the same symmetries when present in structures comprising ferromagnetic and nonmagnetic layers through their induced current-driven spin torques or induced voltages. Although a short chronological overview of the evolution of the spin Hall effect field and the resolution of some early controversies is given, the main body of this review is structured from a pedagogical

  2. Reconstruction of chaotic saddles by classification of unstable periodic orbits: Kuramoto-Sivashinsky equation

    International Nuclear Information System (INIS)

    Saiki, Yoshitaka; Yamada, Michio; Chian, Abraham C.-L.; Miranda, Rodrigo A.; Rempel, Erico L.

    2015-01-01

    The unstable periodic orbits (UPOs) embedded in a chaotic attractor after an attractor merging crisis (MC) are classified into three subsets, and employed to reconstruct chaotic saddles in the Kuramoto-Sivashinsky equation. It is shown that in the post-MC regime, the two chaotic saddles evolved from the two coexisting chaotic attractors before crisis can be reconstructed from the UPOs embedded in the pre-MC chaotic attractors. The reconstruction also involves the detection of the mediating UPO responsible for the crisis, and the UPOs created after crisis that fill the gap regions of the chaotic saddles. We show that the gap UPOs originate from saddle-node, period-doubling, and pitchfork bifurcations inside the periodic windows in the post-MC chaotic region of the bifurcation diagram. The chaotic attractor in the post-MC regime is found to be the closure of gap UPOs

  3. Reconstruction of chaotic saddles by classification of unstable periodic orbits: Kuramoto-Sivashinsky equation

    Energy Technology Data Exchange (ETDEWEB)

    Saiki, Yoshitaka, E-mail: yoshi.saiki@r.hit-u.ac.jp [Graduate School of Commerce and Management, Hitotsubashi University, Tokyo 186-8601 (Japan); Yamada, Michio [Research Institute for Mathematical Sciences (RIMS), Kyoto University, Kyoto 606-8502 (Japan); Chian, Abraham C.-L. [Paris Observatory, LESIA, CNRS, 92195 Meudon (France); National Institute for Space Research (INPE), P.O. Box 515, São José dos Campos, São Paulo 12227-010 (Brazil); Institute of Aeronautical Technology (ITA) and World Institute for Space Environment Research (WISER), São José dos Campos, São Paulo 12228-900 (Brazil); School of Mathematical Sciences, University of Adelaide, Adelaide SA 5005 (Australia); Department of Biomedical Engineering, George Washington University, Washington, DC 20052 (United States); Miranda, Rodrigo A. [Faculty UnB-Gama, and Plasma Physics Laboratory, Institute of Physics, University of Brasília (UnB), Brasília DF 70910-900 (Brazil); Rempel, Erico L. [Institute of Aeronautical Technology (ITA) and World Institute for Space Environment Research (WISER), São José dos Campos, São Paulo 12228-900 (Brazil)

    2015-10-15

    The unstable periodic orbits (UPOs) embedded in a chaotic attractor after an attractor merging crisis (MC) are classified into three subsets, and employed to reconstruct chaotic saddles in the Kuramoto-Sivashinsky equation. It is shown that in the post-MC regime, the two chaotic saddles evolved from the two coexisting chaotic attractors before crisis can be reconstructed from the UPOs embedded in the pre-MC chaotic attractors. The reconstruction also involves the detection of the mediating UPO responsible for the crisis, and the UPOs created after crisis that fill the gap regions of the chaotic saddles. We show that the gap UPOs originate from saddle-node, period-doubling, and pitchfork bifurcations inside the periodic windows in the post-MC chaotic region of the bifurcation diagram. The chaotic attractor in the post-MC regime is found to be the closure of gap UPOs.

  4. Paired Hall states

    International Nuclear Information System (INIS)

    Greiter, M.

    1992-01-01

    This dissertation contains a collection of individual articles on various topics. Their significance in the corresponding field as well as connections between them are emphasized in a general and comprehensive introduction. In the first article, the author explores the consequences for macroscopic effective Lagrangians of assuming that the momentum density is proportional to the flow of conserved current. The universal corrections obtained for the macroscopic Lagrangian of a superconductor describe the London Hall effect, and provide a fully consistent derivation of it. In the second article, a heuristic principle is proposed for quantized Hall states: the existence and incompressibility of fractionally quantized Hall states is explained by an argument based on an adiabatic localization of magnetic flux, the process of trading uniform flux for an equal amount of fictitious flux attached to the particles. This principle is exactly implemented in the third article. For a certain class of model Hamiltonians, the author obtains Laughlin's Jastrow type wave functions explicitly from a filled Landau level, by smooth extrapolation in quantum statistics. The generalization of this analysis to the torus geometry shows that theorems restricting the possibilities of quantum statistics on closed surfaces are circumvented in the presence of a magnetic field. In the last article, the existence is proposed of a novel incompressible quantum liquid, a paired Hall state, at a half filled Landau level. This state arises adiabatically from free fermions in zero magnetic field, and reduces to a state previously proposed by Halperin in the limit of tightly bound pairs. It supports unusual excitations, including neutral fermions and charge e/4 anyons with statistical parameter θ = π/8

  5. Guild Hall retrofit

    Energy Technology Data Exchange (ETDEWEB)

    1984-08-01

    This report demonstrates the economic viability of an exterior rewrap retrofit performed on a public community facility for the performing arts. This facility originally consisted of two mess halls built by the American army. The exterior retrofit consisted of constructing a super-insulated passageway to link the two halls as well as completely wrapping the facility with six millimetre polyethylene to provide an airtight barrier. The roofs and walls were reinsulated and insulation levels were increased to RSI 10.5 in the ceilings and RSI 7.7 in the walls. The installation of a propane fuelled furnace was also included in the retrofit package. Prior to the renovations and retrofitting, the Guild Hall facility was almost unusable. The demonstration project transformed the cold, drafty buildings into an attractive, comfortable and functional centre for the performing arts. Heating requirements have been reduced to 500 MJ/m {sup 2} of floor space annually compared to a predicted 1,760 MJ/m{sup 2} of floor space based on HOTCAN analysis of the heating requirements without the energy conservation measures. 9 figs., 10 tabs.

  6. Quantum critical Hall exponents

    CERN Document Server

    Lütken, C A

    2014-01-01

    We investigate a finite size "double scaling" hypothesis using data from an experiment on a quantum Hall system with short range disorder [1-3]. For Hall bars of width w at temperature T the scaling form is w(-mu)T(-kappa), where the critical exponent mu approximate to 0.23 we extract from the data is comparable to the multi-fractal exponent alpha(0) - 2 obtained from the Chalker-Coddington (CC) model [4]. We also use the data to find the approximate location (in the resistivity plane) of seven quantum critical points, all of which closely agree with the predictions derived long ago from the modular symmetry of a toroidal sigma-model with m matter fields [5]. The value nu(8) = 2.60513 ... of the localisation exponent obtained from the m = 8 model is in excellent agreement with the best available numerical value nu(num) = 2.607 +/- 0.004 derived from the CC-model [6]. Existing experimental data appear to favour the m = 9 model, suggesting that the quantum Hall system is not in the same universality class as th...

  7. Topological Hall and Spin Hall Effects in Disordered Skyrmionic Textures

    OpenAIRE

    N'diaye, P. B.; Akosa, C. A.; Manchon, A.

    2016-01-01

    We carry out a throughout study of the topological Hall and topological spin Hall effects in disordered skyrmionic systems: the dimensionless (spin) Hall angles are evaluated across the energy band structure in the multiprobe Landauer-B\\"uttiker formalism and their link to the effective magnetic field emerging from the real space topology of the spin texture is highlighted. We discuss these results for an optimal skyrmion size and for various sizes of the sample and found that the adiabatic a...

  8. Quantum hall effect. A perspective

    International Nuclear Information System (INIS)

    Aoki, Hideo

    2006-01-01

    Novel concepts and phenomena are emerging recently in the physics of quantum Hall effect. This article gives an overview, which starts from the fractional quantum Hall system viewed as an extremely strongly correlated system, and move on to present various phenomena involving internal degrees of freedom (spin and layer), non-equilibrium and optical properties, and finally the spinoff to anomalous Hall effect and the rotating Bose-Einstein condensate. (author)

  9. Magnesium Hall Thruster

    Science.gov (United States)

    Szabo, James J.

    2015-01-01

    This Phase II project is developing a magnesium (Mg) Hall effect thruster system that would open the door for in situ resource utilization (ISRU)-based solar system exploration. Magnesium is light and easy to ionize. For a Mars- Earth transfer, the propellant mass savings with respect to a xenon Hall effect thruster (HET) system are enormous. Magnesium also can be combusted in a rocket with carbon dioxide (CO2) or water (H2O), enabling a multimode propulsion system with propellant sharing and ISRU. In the near term, CO2 and H2O would be collected in situ on Mars or the moon. In the far term, Mg itself would be collected from Martian and lunar regolith. In Phase I, an integrated, medium-power (1- to 3-kW) Mg HET system was developed and tested. Controlled, steady operation at constant voltage and power was demonstrated. Preliminary measurements indicate a specific impulse (Isp) greater than 4,000 s was achieved at a discharge potential of 400 V. The feasibility of delivering fluidized Mg powder to a medium- or high-power thruster also was demonstrated. Phase II of the project evaluated the performance of an integrated, highpower Mg Hall thruster system in a relevant space environment. Researchers improved the medium power thruster system and characterized it in detail. Researchers also designed and built a high-power (8- to 20-kW) Mg HET. A fluidized powder feed system supporting the high-power thruster was built and delivered to Busek Company, Inc.

  10. Spin Hall effect transistor

    Czech Academy of Sciences Publication Activity Database

    Wunderlich, Joerg; Park, B.G.; Irvine, A.C.; Zarbo, Liviu; Rozkotová, E.; Němec, P.; Novák, Vít; Sinova, Jairo; Jungwirth, Tomáš

    2010-01-01

    Roč. 330, č. 6012 (2010), s. 1801-1804 ISSN 0036-8075 R&D Projects: GA AV ČR KAN400100652; GA MŠk LC510 EU Projects: European Commission(XE) 215368 - SemiSpinNet Grant - others:AV ČR(CZ) AP0801 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : spin Hall effect * spintronics * spin transistor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 31.364, year: 2010

  11. Quantum Hall Electron Nematics

    Science.gov (United States)

    MacDonald, Allan

    In 2D electron systems hosted by crystals with hexagonal symmetry, electron nematic phases with spontaneously broken C3 symmetry are expected to occur in the quantum Hall regime when triplets of Landau levels associated with three different Fermi surface pockets are partially filled. The broken symmetry state is driven by intravalley Coulombic exchange interactions that favor spontaneously polarized valley occupations. I will discuss three different examples of 2D electron systems in which this type of broken symmetry state is expected to occur: i) the SnTe (111) surface, ii) the Bi (111) surface. and iii) unbalanced bilayer graphene. This type of quantum Hall electron nematic state has so far been confirmed only in the Bi (111) case, in which the anisotropic quasiparticle wavefunctions of the broken symmetry state were directly imaged. In the SnTe case the nematic state phase boundary is controlled by a competition between intravalley Coulomb interactions and intervalley scattering processes that increase in relative strength with magnetic field. An in-plane Zeeman field alters the phase diagram by lifting the three-fold Landau level degeneracy, yielding a ground state energy with 2 π/3 periodicity as a function of Zeeman-field orientation angle. I will comment on the possibility of observing similar states in the absence of a magnetic field. Supported by DOE Division of Materials Sciences and Engineering Grant DE-FG03-02ER45958.

  12. The ISOLDE hall

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Since 1992, after its move from the 600 MeV SC, ISOLDE is a customer of the Booster (then 1 GeV, now 1.4 GeV). The intense Booster beam (some 3E13 protons per pulse) is directed onto a target, from which a mixture of isotopes emanates. After ionization and electrostatic acceleration to 60 keV, they enter one of the 2 spectrometers (General Purpose Separator: GPS, and High Resolution Separator: HRS) from which the selected ions are directed to the experiments. The photos show: the REX-ISOLDE post accelerator; the mini-ball experiment; an overview of the ISOLDE hall. In the picture (_12) of the hall, the separators are behind the wall. From either of them, beams can be directed into any of the many beamlines towards the experiments, some of which are visible in the foreground. The elevated cubicle at the left is EBIS (Electron Beam Ion Source), which acts as a charge-state multiplier for the REX facility. The ions are further mass analzyzed and passed on to the linac which accelerates them to higher energies. T...

  13. Energy consumption of sport halls

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    The energy consumption of Finland's sports halls (ball games halls, ice hockey halls and swimming halls) represent approximately 1% of that of the country's whole building stock. In the light of the facts revealed by the energy study the potential energy saving rate in sports halls is 15-25%. The total savings would be something like FIM 30-40 million per annum, of which about a half would be achieved without energy-economic investments only by changing utilization habits and by automatic control measures. The energy-economic investments are for the most part connected with ventilation and their repayment period is from one to five years. On the basis of the energy study the following specific consumption are presented as target values: swimming halls: heat (kWh/m*H3/a)100, electricity (kWh/m*H3/a)35, water (l/m*H3/a)1000 icehockey halls (warm): heat (kWh/m*H3/a)25, electricity (kWh/m*H3/a)15, water (l/m*H3/a)200, ball games halls (multi-purpose halls): heat (kWh/m*H3/a)30, electricity (kWh/m*H3/a)25, water (l/m*H3/a)130. In the study the following points proved to be the central areas of energy saving in sports halls: 1. Flexible regulation of the temperature in sports spaces on the basis of the sport in question. 2. The ventilation of swimming halls should be adjusted in such a way that the humidity of the hall air would comply with the limit humidity curve determined by the quality of structures and the temperature of the outdoor air. 3. An ice skating hall is an establishment producing condensing energy from 8 to 9 months a year worth of approx. 100.000-150.000 Finnmarks. The development of the recovery of condensing energy has become more important. 4. The ventilation of ball games halls may account for over 50% of the energy consumption of the whole building. Therefore special attention should be paid to the optimatization of ventilation as a whole.

  14. Scanning vector Hall probe microscopy

    International Nuclear Information System (INIS)

    Cambel, V.; Gregusova, D.; Fedor, J.; Kudela, R.; Bending, S.J.

    2004-01-01

    We have developed a scanning vector Hall probe microscope for mapping magnetic field vector over magnetic samples. The microscope is based on a micromachined Hall sensor and the cryostat with scanning system. The vector Hall sensor active area is ∼5x5 μm 2 . It is realized by patterning three Hall probes on the tilted faces of GaAs pyramids. Data from these 'tilted' Hall probes are used to reconstruct the full magnetic field vector. The scanning area of the microscope is 5x5 mm 2 , space resolution 2.5 μm, field resolution ∼1 μT Hz -1/2 at temperatures 10-300 K

  15. On Hall current fluid

    International Nuclear Information System (INIS)

    Shen, M.C.; Ebel, D.

    1987-01-01

    In this paper some new results concerning magnetohydrodynamic (MHD) equations with the Hall current (HC) term in the Ohm's law are presented. For the cylindrical pinch of a compressible HC fluid, it is found that for large time and long wave length the solution to the governing equations exhibits the behavior of solitons as in the case of an ideal MHD model. In some special cases, the HC model appears to be better posed. An open question is whether a simple toroidal equilibrium of an HC fluid with resistivity and viscosity exists. The answer to this question is affirmative if the prescribed velocity on the boundary has a small norm. Furthermore, the equilibrium is also linearly and nonlinearly stable

  16. Farm Hall: The Play

    Science.gov (United States)

    Cassidy, David C.

    2013-03-01

    It's July 1945. Germany is in defeat and the atomic bombs are on their way to Japan. Under the direction of Samuel Goudsmit, the Allies are holding some of the top German nuclear scientists-among them Heisenberg, Hahn, and Gerlach-captive in Farm Hall, an English country manor near Cambridge, England. As secret microphones record their conversations, the scientists are unaware of why they are being held or for how long. Thinking themselves far ahead of the Allies, how will they react to the news of the atomic bombs? How will these famous scientists explain to themselves and to the world their failure to achieve even a chain reaction? How will they come to terms with the horror of the Third Reich, their work for such a regime, and their behavior during that period? This one-act play is based upon the transcripts of their conversations as well as the author's historical work on the subject.

  17. Quantum Hall effect

    International Nuclear Information System (INIS)

    Joynt, R.J.

    1982-01-01

    A general investigation of the electronic structure of two dimensional systems is undertaken with a view towards understanding the quantum Hall effect. The work is limited to the case of a strong perpendicular magnetic field, with a disordered potential and an externally applied electric field. The electrons are treated as noninteracting. First, the scattering theory of the system is worked out. The surprising result is found that a wavepacket will reform after scattering from an isolated potential. Also it will tend to be accelerated in the neighborhood of the scatterer if the potential has bound states. Fredholm theory can then be used to show that the extended states carry an additional current which compensates for the zero current of the bound states. Together, these give the quantized conductance. The complementary case of a smooth random potential is treated by a path-integral approach which exploits the analogies to the classical equations of motion. The Green's function can be calculated approximately, which gives the general character of both the bound and extended states. Also the ratio of these two types of states can be computed for a given potential. The charge density is uniform in first approximation, and the Hall conductance is quantized. Higher-order corrections for more rapidly fluctuating potential are calculated. The most general conditions under which the conductance is quantized are discussed. Because of the peculiar scattering properties of the system, numerical solution of the Schroedinger equation is of interest, both to confirm the analytical results, and for pedagogical reasons. The stability and convergence problems inherent in the computer solution of the problem are analyzed. Results for some model scattering potentials are presented

  18. Influence of girth strap placement and panel flocking material on the saddle pressure pattern during riding of horses.

    Science.gov (United States)

    Byström, A; Stalfelt, A; Egenvall, A; Von Peinen, K; Morgan, K; Roepstorff, L

    2010-11-01

    Saddle fit is well recognised as an important factor for the health and performance of riding horses. However, only few studies have addressed general effects of different saddle construction details within a group of horses. To assess the influence of girth strap placement, traditional vs. v-system, and panel flocking material, wool vs. synthetic foam, on the saddle pressure pattern during riding. Six horses were ridden by 3 riders in sitting and rising trot and sitting canter. Saddle pressure was measured with 3 different saddle variants: 1) wool flocked panels and traditional girthing (baseline); 2) wool flocked panels and v-system girthing; and 3) foam filled panels and traditional girthing. From the pressure data, a number of descriptive variables were extracted. These were analysed using ANCOVA models with horse, rider, saddle, seat (sitting/rising, trot only) and speed as independent variables. With foam filled panels stride maximum pressures under the hind part of the saddle increased by 7-12% and the area under the saddle with a stride mean pressure >11 kPa increased by 114 cm(2) in trot and 127 cm(2) in canter. With v-system girthing, the latter variable also increased, but only by 53 and 38 cm(2) in trot and canter, respectively. In addition, stride maximum pressures under the front part of the saddle tended to increase (≤ 9%). Both flocking material and girthing have a significant influence on the saddle pressure and should thus be considered in saddle fitting. Wool seems a better flocking material than foam of the type used in the current study. For girthing, traditional placement seems equally good if not better than the v-system. However, further studies are needed to show if these results are valid for a larger population of riding horses. © 2010 EVJ Ltd.

  19. Modular invariance, universality and crossover in the quantum Hall effect

    International Nuclear Information System (INIS)

    Dolan, Brian P.

    1999-01-01

    An analytic form for the conductivity tensor in crossover between two quantum Hall plateaux is derived, which appears to be in good agreement with existing experimental data. The derivation relies on an assumed symmetry between quantum Hall states, a generalisation of the law of corresponding states from rational filling factors to complex conductivity, which has a mathematical expression in terms of an action of the modular group on the upper-half complex conductivity plane. This symmetry implies universality in quantum Hall crossovers. The assumption that the β-function for the complex conductivity is a complex analytic function, together with some experimental constraints, results in an analytic expression for the crossover, as a function of the external magnetic field

  20. Hall Effect Gyrators and Circulators

    Science.gov (United States)

    Viola, Giovanni; DiVincenzo, David P.

    2014-04-01

    The electronic circulator and its close relative the gyrator are invaluable tools for noise management and signal routing in the current generation of low-temperature microwave systems for the implementation of new quantum technologies. The current implementation of these devices using the Faraday effect is satisfactory but requires a bulky structure whose physical dimension is close to the microwave wavelength employed. The Hall effect is an alternative nonreciprocal effect that can also be used to produce desired device functionality. We review earlier efforts to use an Ohmically contacted four-terminal Hall bar, explaining why this approach leads to unacceptably high device loss. We find that capacitive coupling to such a Hall conductor has much greater promise for achieving good circulator and gyrator functionality. We formulate a classical Ohm-Hall analysis for calculating the properties of such a device, and show how this classical theory simplifies remarkably in the limiting case of the Hall angle approaching 90°. In this limit, we find that either a four-terminal or a three-terminal capacitive device can give excellent circulator behavior, with device dimensions far smaller than the ac wavelength. An experiment is proposed to achieve GHz-band gyration in millimeter (and smaller) scale structures employing either semiconductor heterostructure or graphene Hall conductors. An inductively coupled scheme for realizing a Hall gyrator is also analyzed.

  1. Topological Hall and spin Hall effects in disordered skyrmionic textures

    KAUST Repository

    Ndiaye, Papa Birame; Akosa, Collins Ashu; Manchon, Aurelien

    2017-01-01

    We carry out a thorough study of the topological Hall and topological spin Hall effects in disordered skyrmionic systems: the dimensionless (spin) Hall angles are evaluated across the energy-band structure in the multiprobe Landauer-Büttiker formalism and their link to the effective magnetic field emerging from the real-space topology of the spin texture is highlighted. We discuss these results for an optimal skyrmion size and for various sizes of the sample and find that the adiabatic approximation still holds for large skyrmions as well as for nanoskyrmions. Finally, we test the robustness of the topological signals against disorder strength and show that the topological Hall effect is highly sensitive to momentum scattering.

  2. Topological Hall and spin Hall effects in disordered skyrmionic textures

    KAUST Repository

    Ndiaye, Papa Birame

    2017-02-24

    We carry out a thorough study of the topological Hall and topological spin Hall effects in disordered skyrmionic systems: the dimensionless (spin) Hall angles are evaluated across the energy-band structure in the multiprobe Landauer-Büttiker formalism and their link to the effective magnetic field emerging from the real-space topology of the spin texture is highlighted. We discuss these results for an optimal skyrmion size and for various sizes of the sample and find that the adiabatic approximation still holds for large skyrmions as well as for nanoskyrmions. Finally, we test the robustness of the topological signals against disorder strength and show that the topological Hall effect is highly sensitive to momentum scattering.

  3. Tuning giant anomalous Hall resistance ratio in perpendicular Hall balance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J. Y.; Yang, G. [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, S. G., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Liu, J. L. [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Wang, R. M. [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Amsellem, E.; Kohn, A. [Department of Materials Engineering, Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Yu, G. H., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-04-13

    Anomalous Hall effect at room temperature in perpendicular Hall balance with a core structure of [Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4} has been tuned by functional CoO layers, where [Pt/Co]{sub 4} multilayers exhibit perpendicular magnetic anisotropy. A giant Hall resistance ratio up to 69 900% and saturation Hall resistance (R{sub S}{sup P}) up to 2590 mΩ were obtained in CoO/[Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4}/CoO system, which is 302% and 146% larger than that in the structure without CoO layers, respectively. Transmission electron microscopy shows highly textured [Co/Pt]{sub 4} multilayers and oxide layers with local epitaxial relations, indicating that the crystallographic structure has significant influence on spin dependent transport properties.

  4. Anomalous Hall effect

    Science.gov (United States)

    Nagaosa, Naoto; Sinova, Jairo; Onoda, Shigeki; MacDonald, A. H.; Ong, N. P.

    2010-04-01

    The anomalous Hall effect (AHE) occurs in solids with broken time-reversal symmetry, typically in a ferromagnetic phase, as a consequence of spin-orbit coupling. Experimental and theoretical studies of the AHE are reviewed, focusing on recent developments that have provided a more complete framework for understanding this subtle phenomenon and have, in many instances, replaced controversy by clarity. Synergy between experimental and theoretical works, both playing a crucial role, has been at the heart of these advances. On the theoretical front, the adoption of the Berry-phase concepts has established a link between the AHE and the topological nature of the Hall currents. On the experimental front, new experimental studies of the AHE in transition metals, transition-metal oxides, spinels, pyrochlores, and metallic dilute magnetic semiconductors have established systematic trends. These two developments, in concert with first-principles electronic structure calculations, strongly favor the dominance of an intrinsic Berry-phase-related AHE mechanism in metallic ferromagnets with moderate conductivity. The intrinsic AHE can be expressed in terms of the Berry-phase curvatures and it is therefore an intrinsic quantum-mechanical property of a perfect crystal. An extrinsic mechanism, skew scattering from disorder, tends to dominate the AHE in highly conductive ferromagnets. The full modern semiclassical treatment of the AHE is reviewed which incorporates an anomalous contribution to wave-packet group velocity due to momentum-space Berry curvatures and correctly combines the roles of intrinsic and extrinsic (skew-scattering and side-jump) scattering-related mechanisms. In addition, more rigorous quantum-mechanical treatments based on the Kubo and Keldysh formalisms are reviewed, taking into account multiband effects, and demonstrate the equivalence of all three linear response theories in the metallic regime. Building on results from recent experiment and theory, a

  5. Planar Hall effect bridge magnetic field sensors

    DEFF Research Database (Denmark)

    Henriksen, A.D.; Dalslet, Bjarke Thomas; Skieller, D.H.

    2010-01-01

    Until now, the planar Hall effect has been studied in samples with cross-shaped Hall geometry. We demonstrate theoretically and experimentally that the planar Hall effect can be observed for an exchange-biased ferromagnetic material in a Wheatstone bridge topology and that the sensor signal can...... Hall effect bridge sensors....

  6. Gauge invariance and fractional quantized Hall effect

    International Nuclear Information System (INIS)

    Tao, R.; Wu, Y.S.

    1984-01-01

    It is shown that gauge invariance arguments imply the possibility of fractional quantized Hall effect; the Hall conductance is accurately quantized to a rational value. The ground state of a system showing the fractional quantized Hall effect must be degenerate; the non-degenerate ground state can only produce the integral quantized Hall effect. 12 references

  7. "Hall mees" Linnateatris / Triin Sinissaar

    Index Scriptorium Estoniae

    Sinissaar, Triin

    1999-01-01

    Tallinn Linnateatri ja Raadioteatri ühislavastus "Hall mees" Gill Adamsi näidendi järgi, lavastaja Eero Spriit, osades Helene Vannari ja Väino Laes, kunstnik Kustav - Agu Püüman. Esietendus 22. okt

  8. Sheldon-Hall syndrome

    Directory of Open Access Journals (Sweden)

    Bamshad Michael J

    2009-03-01

    Full Text Available Abstract Sheldon-Hall syndrome (SHS is a rare multiple congenital contracture syndrome characterized by contractures of the distal joints of the limbs, triangular face, downslanting palpebral fissures, small mouth, and high arched palate. Epidemiological data for the prevalence of SHS are not available, but less than 100 cases have been reported in the literature. Other common clinical features of SHS include prominent nasolabial folds, high arched palate, attached earlobes, mild cervical webbing, short stature, severe camptodactyly, ulnar deviation, and vertical talus and/or talipes equinovarus. Typically, the contractures are most severe at birth and non-progressive. SHS is inherited in an autosomal dominant pattern but about half the cases are sporadic. Mutations in either MYH3, TNNI2, or TNNT3 have been found in about 50% of cases. These genes encode proteins of the contractile apparatus of fast twitch skeletal muscle fibers. The diagnosis of SHS is based on clinical criteria. Mutation analysis is useful to distinguish SHS from arthrogryposis syndromes with similar features (e.g. distal arthrogryposis 1 and Freeman-Sheldon syndrome. Prenatal diagnosis by ultrasonography is feasible at 18–24 weeks of gestation. If the family history is positive and the mutation is known in the family, prenatal molecular genetic diagnosis is possible. There is no specific therapy for SHS. However, patients benefit from early intervention with occupational and physical therapy, serial casting, and/or surgery. Life expectancy and cognitive abilities are normal.

  9. Stable discretization of poroelasticity problems and efficient preconditioners for arising saddle point type matrices

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe; Blaheta, Radim; Byczanski, Petr

    2012-01-01

    Roč. 15, č. 4 (2012), s. 191-207 ISSN 1432-9360 R&D Projects: GA MŠk ED1.1.00/02.0070 Institutional support: RVO:68145535 Keywords : poroelasticity * saddle point matrices * preconditioning * stability of discretization Subject RIV: BA - General Mathematics http://link.springer.com/article/10.1007/s00791-013-0209-0

  10. Generalized saddle point condition for ignition in a tokamak reactor with temperature and density profiles

    International Nuclear Information System (INIS)

    Mitari, O.; Hirose, A.; Skarsgard, H.M.

    1989-01-01

    In this paper, the concept of a generalized ignition contour map, is extended to the realistic case of a plasma with temperature and density profiles in order to study access to ignition in a tokamak reactor. The generalized saddle point is found to lie between the Lawson and ignition conditions. If the height of the operation path with Goldston L-mode scaling is higher than the generalized saddle point, a reactor can reach ignition with this scaling for the case with no confinement degradation effect due to alpha-particle heating. In this sense, the saddle point given in a general form is a new criterion for reaching ignition. Peaking the profiles for the plasma temperature and density can lower the height of the generalized saddle point and help a reactor to reach ignition. With this in mind, the authors can judge whether next-generation tokamaks, such as Compact Ignition Tokamak, Tokamak Ignition/Burn Experimental Reactor, Next European Torus, Fusion Experimental Reactor, International Tokamak Reactor, and AC Tokamak Reactor, can reach ignition with realistic profile parameters and an L-mode scaling law

  11. Basic kinematics of the saddle and rider in high-level dressage horses trotting on a treadmill.

    Science.gov (United States)

    Byström, A; Rhodin, M; von Peinen, K; Weishaupt, M A; Roepstorff, L

    2009-03-01

    A comprehensive kinematic description of rider and saddle movements is not yet present in the scientific literature. To describe saddle and rider movements in a group of high-level dressage horses and riders. Seven high-level dressage horses and riders were subjected to kinematic measurements while performing collected trot on a treadmill. For analysis a rigid body model for the saddle and core rider segments, projection angles of the rider's extremities and the neck and trunk of the horse, and distances between markers selected to indicate rider position were used. For a majority of the variables measured it was possible to describe a common pattern for the group. Rotations around the transverse axis (pitch) were generally biphasic for each diagonal. During the first half of stance the saddle rotated anti-clockwise and the rider's pelvis clockwise viewed from the right and the rider's lumbar back extended. During the later part of stance and the suspension phase reverse pitch rotations were observed. Rotations of the saddle and core rider segments around the longitudinal (roll) and vertical axes (yaw) changed direction only around time of contact of each diagonal. The saddles and riders of high-level dressage horses follow a common movement pattern at collected trot. The movements of the saddle and rider are clearly related to the movements of the horse and saddle movements also seem to be influenced by the rider. Knowledge about rider and saddle movements can further our understanding of, and hence possibilities to prevent, orthopaedic injuries related to the exposure of the horse to a rider and saddle.

  12. Anode sheath in Hall thrusters

    International Nuclear Information System (INIS)

    Dorf, L.; Semenov, V.; Raitses, Y.

    2003-01-01

    A set of hydrodynamic equations is used to describe quasineutral plasma in ionization and acceleration regions of a Hall thruster. The electron distribution function and Poisson equation are invoked for description of a near-anode region. Numerical solutions suggest that steady-state operation of a Hall thruster can be achieved at different anode sheath regimes. It is shown that the anode sheath depends on the thruster operating conditions, namely the discharge voltage and the mass flow rate

  13. Theory of spin Hall effect

    OpenAIRE

    Chudnovsky, Eugene M.

    2007-01-01

    An extension of Drude model is proposed that accounts for spin and spin-orbit interaction of charge carriers. Spin currents appear due to combined action of the external electric field, crystal field and scattering of charge carriers. The expression for spin Hall conductivity is derived for metals and semiconductors that is independent of the scattering mechanism. In cubic metals, spin Hall conductivity $\\sigma_s$ and charge conductivity $\\sigma_c$ are related through $\\sigma_s = [2 \\pi \\hbar...

  14. Optimization of Cylindrical Hall Thrusters

    International Nuclear Information System (INIS)

    Raitses, Yevgeny; Smirnov, Artem; Granstedt, Erik; Fisch, Nathaniel J.

    2007-01-01

    The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation.

  15. Optimization of Cylindrical Hall Thrusters

    International Nuclear Information System (INIS)

    Raitses, Yevgeny; Smirnov, Artem; Granstedt, Erik; Fi, Nathaniel J.

    2007-01-01

    The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation

  16. Not your grandfather's concert hall

    Science.gov (United States)

    Cooper, Russell; Malenka, Richard; Griffith, Charles; Friedlander, Steven

    2004-05-01

    The opening of Judy and Arthur Zankel Hall on 12 September 2003, restores Andrew Carnegie's original 1891 concept of having three outstanding auditoriums of different sizes under one roof, and creates a 21st-century venue for music performance and education. With concerts ranging from early music to avant-garde multimedia productions, from jazz to world music, and from solo recitals to chamber music, Zankel Hall expands the breadth and depth of Carnegie Hall's offerings. It allows for the integration of programming across three halls with minifestivals tailored both to the size and strengths of each hall and to the artists and music to be performed. The new flexible space also provides Carnegie Hall with an education center equipped with advanced communications technology. This paper discusses the unique program planned for this facility and how the architects, theatre consultants, and acousticians developed a design that fulfilled the client's expectations and coordinated the construction of the facility under the floor of the main Isaac Stern Auditorium without having to cancel a single performance.

  17. Iodine Hall Thruster

    Science.gov (United States)

    Szabo, James

    2015-01-01

    Iodine enables dramatic mass and cost savings for lunar and Mars cargo missions, including Earth escape and near-Earth space maneuvers. The demonstrated throttling ability of iodine is important for a singular thruster that might be called upon to propel a spacecraft from Earth to Mars or Venus. The ability to throttle efficiently is even more important for missions beyond Mars. In the Phase I project, Busek Company, Inc., tested an existing Hall thruster, the BHT-8000, on iodine propellant. The thruster was fed by a high-flow iodine feed system and supported by an existing Busek hollow cathode flowing xenon gas. The Phase I propellant feed system was evolved from a previously demonstrated laboratory feed system. Throttling of the thruster between 2 and 11 kW at 200 to 600 V was demonstrated. Testing showed that the efficiency of iodine fueled BHT-8000 is the same as with xenon, with iodine delivering a slightly higher thrust-to-power (T/P) ratio. In Phase II, a complete iodine-fueled system was developed, including the thruster, hollow cathode, and iodine propellant feed system. The nominal power of the Phase II system is 8 kW; however, it can be deeply throttled as well as clustered to much higher power levels. The technology also can be scaled to greater than 100 kW per thruster to support megawatt-class missions. The target thruster efficiency for the full-scale system is 65 percent at high specific impulse (Isp) (approximately 3,000 s) and 60 percent at high thrust (Isp approximately 2,000 s).

  18. ac spin-Hall effect

    International Nuclear Information System (INIS)

    Entin-Wohlman, O.

    2005-01-01

    Full Text:The spin-Hall effect is described. The Rashba and Dresselhaus spin-orbit interactions are both shown to yield the low temperature spin-Hall effect for strongly localized electrons coupled to phonons. A frequency-dependent electric field E(ω) generates a spin-polarization current, normal to E, due to interference of hopping paths. At zero temperature the corresponding spin-Hall conductivity is real and is proportional to ω 2 . At non-zero temperatures the coupling to the phonons yields an imaginary term proportional to ω. The interference also yields persistent spin currents at thermal equilibrium, at E = 0. The contributions from the Dresselhaus and Rashba interactions to the interference oppose each other

  19. Complex saddle points and the sign problem in complex Langevin simulation

    International Nuclear Information System (INIS)

    Hayata, Tomoya; Hidaka, Yoshimasa; Tanizaki, Yuya

    2016-01-01

    We show that complex Langevin simulation converges to a wrong result within the semiclassical analysis, by relating it to the Lefschetz-thimble path integral, when the path-integral weight has different phases among dominant complex saddle points. Equilibrium solution of the complex Langevin equation forms local distributions around complex saddle points. Its ensemble average approximately becomes a direct sum of the average in each local distribution, where relative phases among them are dropped. We propose that by taking these phases into account through reweighting, we can solve the wrong convergence problem. However, this prescription may lead to a recurrence of the sign problem in the complex Langevin method for quantum many-body systems.

  20. Saddle-shaped reticulate Nummulites from Early Oligocene rocks of Khari area, SW Kutch, India

    Science.gov (United States)

    Sengupta, S.; Sarkar, Sampa; Mukhopadhyay, S.

    2011-04-01

    Saddle-shaped reticulate Nummulites from the Early Oligocene rocks of Khari area, SW Kutch, India is reported here for the first time. Unusual shape of this Nummulites is due to the curved nature of the coiling plane, indicating space constrained postembryonic test growth. With regular development of chambers, septa and septal filaments, the saddle-shaped Nummulites constitutes the third morphotype of N. cf. fichteli Michelotti form A. Other morphotypes of the species reported earlier include inflated lenticular and conical tests. Multiple morphotypes of N. cf. fichteli form A indicates varied test growth in response to substrate conditions. Morphological variability exhibited by N. cf. fichteli form A from Kutch and some Early Oligocene reticulate Nummulites from the Far East are comparable. This faunal suite is morphologically distinct from the contemporary reticulate Nummulites of the European localities.

  1. Localized saddle-point search and application to temperature-accelerated dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Yunsic; Amar, Jacques G. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Callahan, Nathan B. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States)

    2013-03-07

    We present a method for speeding up temperature-accelerated dynamics (TAD) simulations by carrying out a localized saddle-point (LSAD) search. In this method, instead of using the entire system to determine the energy barriers of activated processes, the calculation is localized by only including a small chunk of atoms around the atoms directly involved in the transition. Using this method, we have obtained N-independent scaling for the computational cost of the saddle-point search as a function of system size N. The error arising from localization is analyzed using a variety of model systems, including a variety of activated processes on Ag(100) and Cu(100) surfaces, as well as multiatom moves in Cu radiation damage and metal heteroepitaxial growth. Our results show significantly improved performance of TAD with the LSAD method, for the case of Ag/Ag(100) annealing and Cu/Cu(100) growth, while maintaining a negligibly small error in energy barriers.

  2. Exotic Homoclinic Surface of a Saddle-Node Limit Cycle in a Leech Neuron Model

    Science.gov (United States)

    Yooer, Chi-Feng; Wei, Fang; Xu, Jian-Xue; Zhang, Xin-Hua

    2011-03-01

    We carry out numerical and theoretical investigations on the global unstable invariant set (manifold) of a saddle-node limit cycle in a leech heart interneuron model. The corresponding global bifurcation is accompanied by an explosion of secondary bifurcations of limit cycles and the emergence of loop-shaped bifurcation structures. The dynamical behaviors of the trajectories of the invariant set are very complicated and can only be partially explained by existing theories.

  3. A description of a wide beam saddle field ion source used for nuclear target applications

    International Nuclear Information System (INIS)

    Greene, J.P.; Schiel, S.L.; Thomas, G.E.

    1997-01-01

    A description is given of a new, wide beam saddle field sputter source used for the preparation of targets applied in nuclear physics experiments. The ion source characteristics are presented and compared with published results obtained with other sources. Deposition rates acquired utilizing this source are given for a variety of target materials encountered in nuclear target production. New applications involving target thinning and ion milling are discussed

  4. On Signed Incomplete Cholesky Factorization Preconditioners for Saddle-Point Systems

    Czech Academy of Sciences Publication Activity Database

    Scott, J.; Tůma, Miroslav

    2014-01-01

    Roč. 36, č. 6 (2014), A2984-A3010 ISSN 1064-8275 R&D Projects: GA ČR GA13-06684S Grant - others:EPSRC(GB) EP/I013067/1 Program:GA Institutional support: RVO:67985807 Keywords : sparse matrices * sparse linear systems * indefinite symmetric systems * saddle-point systems * iterative solvers * preconditioning * incomplete Cholesky factorization Subject RIV: BA - General Mathematics Impact factor: 1.854, year: 2014

  5. Investment decisions in the South African saddle horse industry / Johannes Hendrik Dreyer

    OpenAIRE

    Dreyer, Johannes Hendrik

    2014-01-01

    This study originated in the phenomenon that has been observed in the South African Saddle Horse Industry of substantial investments being made over time in the absence of obvious financial or economic reward. A literature study confirmed that, internationally, investment without obvious financial and economic rewards is not unknown and at the same time it was obvious that it is a rarely studied subject. From the literature study it was also evident that this phenomenon occurs ...

  6. Saddle-splay screening and chiral symmetry breaking in toroidal nematics

    OpenAIRE

    Koning, Vinzenz; van Zuiden, Benjamin C.; Kamien, Randall D.; Vitelli, Vincenzo

    2013-01-01

    We present a theoretical study of director fields in toroidal geometries with degenerate planar boundary conditions. We find spontaneous chirality: despite the achiral nature of nematics the director configuration show a handedness if the toroid is thick enough. In the chiral state the director field displays a double twist, whereas in the achiral state there is only bend deformation. The critical thickness increases as the difference between the twist and saddle-splay moduli grows. A positiv...

  7. Corrigendum to Preconditioners for regularized saddle point problems with an application for heterogeneous Darcy flow problems

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe; Blaheta, Radim

    2016-01-01

    Roč. 298, May 2016 (2016), s. 252-255 ISSN 0377-0427 R&D Projects: GA MŠk ED1.1.00/02.0070 Institutional support: RVO:68145535 Keywords : saddle point systems * conditions of nonsingularity * spectrum of preconditioned systems Subject RIV: BA - General Mathematics Impact factor: 1.357, year: 2016 http://www.sciencedirect.com/science/article/pii/S0377042715005889

  8. Preconditioners for regularized saddle point problems with an application for heterogeneous Darcy flow problems

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe; Blaheta, Radim; Byczanski, Petr; Karátson, J.; Ahmad, B.

    2015-01-01

    Roč. 280, č. 280 (2015), s. 141-157 ISSN 0377-0427 R&D Projects: GA MŠk ED1.1.00/02.0070 Institutional support: RVO:68145535 Keywords : preconditioners * heterogeneous coefficients * regularized saddle point Inner–outer iterations * Darcy flow Subject RIV: BA - General Mathematics Impact factor: 1.328, year: 2015 http://www.sciencedirect.com/science/article/pii/S0377042714005238

  9. Limiting Accuracy of Segregated Solution Methods for Nonsymmetric Saddle Point Problems

    Czech Academy of Sciences Publication Activity Database

    Jiránek, P.; Rozložník, Miroslav

    Roc. 215, c. 1 (2008), s. 28-37 ISSN 0377-0427 R&D Projects: GA MŠk 1M0554; GA AV ČR 1ET400300415 Institutional research plan: CEZ:AV0Z10300504 Keywords : saddle point problems * Schur complement reduction method * null-space projection method * rounding error analysis Subject RIV: BA - General Mathematics Impact factor: 1.048, year: 2008

  10. On the Use of the Main-sequence Knee (Saddle) to Measure Globular Cluster Ages

    Science.gov (United States)

    Saracino, S.; Dalessandro, E.; Ferraro, F. R.; Lanzoni, B.; Origlia, L.; Salaris, M.; Pietrinferni, A.; Geisler, D.; Kalirai, J. S.; Correnti, M.; Cohen, R. E.; Mauro, F.; Villanova, S.; Moni Bidin, C.

    2018-06-01

    In this paper, we review the operational definition of the so-called main-sequence knee (MS-knee), a feature in the color-magnitude diagram (CMD) occurring at the low-mass end of the MS. The magnitude of this feature is predicted to be independent of age at fixed chemical composition. For this reason, its difference in magnitude with respect to the MS turn-off (MS-TO) point has been suggested as a possible diagnostic to estimate absolute globular cluster (GC) ages. We first demonstrate that the operational definition of the MS-knee currently adopted in the literature refers to the inflection point of the MS (which we here more appropriately named MS-saddle), a feature that is well distinct from the knee and which cannot be used as its proxy. The MS-knee is only visible in near-infrared CMDs, while the MS-saddle can be also detected in optical–NIR CMDs. By using different sets of isochrones, we then demonstrate that the absolute magnitude of the MS-knee varies by a few tenths of a dex from one model to another, thus showing that at the moment stellar models may not capture the full systematic error in the method. We also demonstrate that while the absolute magnitude of the MS-saddle is almost coincident in different models, it has a systematic dependence on the adopted color combinations which is not predicted by stellar models. Hence, it cannot be used as a reliable reference for absolute age determination. Moreover, when statistical and systematic uncertainties are properly taken into account, the difference in magnitude between the MS-TO and the MS-saddle does not provide absolute ages with better accuracy than other methods like the MS-fitting.

  11. Parametric CAD and Fea Model of a Saddle Tapping Tee

    DEFF Research Database (Denmark)

    A. Kristensen, Anders Schmidt; Lund Jepsen, Kristian

    2007-01-01

     Often it is necessary to branch of a pipe section on an oilrig. This operation is often performed by making a so-called "Hot Tapping", which involves welding a pipe and a flange on to the pipe section. A spherical valve and a gate are mounted on to the flange, i.e. weld-o-let. In order to perform...... the welding operations a so-called habitat must be constructed. This habitat encapsulates the "Hot Tapping" spot and is relatively costly. Thus, to avoid weld operations on to the pipeline, a solution with clamps has been developed, i.e. a Saddle Tapping Tee. The Saddle Tapping Tee is clamped on the pipe...... is determined from paragraph K302.3.2 in ASME B31.3. A full parametric 3D CAD model of the Saddle Tapping Tee is developed where a number of user-defined parameters are controlled from an Excel spreadsheet allowing parameter studies and technical documentation to be generated effectively. The same Excel spread...

  12. Effect of saddle-point anisotropy on point-defect drift-diffusion into straight dislocations

    International Nuclear Information System (INIS)

    Skinner, B.C.; Woo, C.H.

    1983-02-01

    Effects on point-defect drift-diffusion in the strain fields of edge or screw dislocations, due to the anisotropy of the point defect in its saddle-point configuration, are investigated. Expressions for sink strength and bias that include the saddle-point shape effect are derived, both in the absence and presence of an externally applied stress. These are found to depend on intrinsic parameters such as the relaxation volume and the saddle-point shape of the point defects, and extrinsic parameters such as temperature and the magnitude and direction of the externally applied stress with respect to the line direction and Burgers vector direction of the dislocation. The theory is applied to fcc copper and bcc iron. It is found that screw dislocations are biased sinks and that the stress-induced bias differential for the edge dislocations depends much more on the line direction than the Burgers vector direction. Comparison with the stress-induced bias differential due to the usual SIPA effect is made. It is found that the present effect causes a bias differential that is more than an order of magnitude larger

  13. ATLAS Assembly Hall Open Day

    CERN Multimedia

    Patrice Loiez

    2004-01-01

    To mark the 50th Anniversary of the founding of CERN, a day of tours, displays and presentations was held in October 2004. The assembly halls for the experiments that were waiting to be installed on the LHC, such as ATLAS shown here, were transformed into display areas and cafés.

  14. Universal intrinsic spin Hall effect

    Czech Academy of Sciences Publication Activity Database

    Sinova, J.; Culcer, D.; Sinitsyn, N. A.; Niu, Q.; Jungwirth, Tomáš; MacDonald, A. H.

    2004-01-01

    Roč. 92, č. 12 (2004), 126603/1-126603/4 ISSN 0031-9007 R&D Projects: GA ČR GA202/02/0912 Institutional research plan: CEZ:AV0Z1010914 Keywords : semiconductor quantum wells * spin-orbit interaction * spin Hall effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.218, year: 2004

  15. Spin Hall effect for anyons

    International Nuclear Information System (INIS)

    Dhar, S.; Basu, B.; Ghosh, Subir

    2007-01-01

    We explain the intrinsic spin Hall effect from generic anyon dynamics in the presence of external electromagnetic field. The free anyon is represented as a spinning particle with an underlying non-commutative configuration space. The Berry curvature plays a major role in the analysis

  16. The Other Hall Effect: College Board Physics

    Science.gov (United States)

    Sheppard, Keith; Gunning, Amanda M.

    2013-01-01

    Edwin Herbert Hall (1855-1938), discoverer of the Hall effect, was one of the first winners of the AAPT Oersted Medal for his contributions to the teaching of physics. While Hall's role in establishing laboratory work in high schools is widely acknowledged, his position as chair of the physics section of the Committee on College Entrance…

  17. Geology and geologic history of the Moscow-Pullman basin, Idaho and Washington, from late Grande Ronde to late Saddle Mountains time

    Science.gov (United States)

    Bush, John H; Garwood, Dean L; Dunlap, Pamela

    2016-01-01

    The Moscow-Pullman basin, located on the eastern margin of the Columbia River flood basalt province, consists of a subsurface mosaic of interlayered Miocene sediments and lava flows of the Imnaha, Grande Ronde, Wanapum, and Saddle Mountains Basalts of the Columbia River Basalt Group. This sequence is ~1800 ft (550 m) thick in the east around Moscow, Idaho, and exceeds 2300 ft (700 m) in the west at Pullman, Washington. Most flows entered from the west into a topographic low, partially surrounded by steep mountainous terrain. These flows caused a rapid rise in base level and deposition of immature sediments. This field guide focuses on the upper Grande Ronde Basalt, Wanapum Basalt, and sediments of the Latah Formation.Late Grande Ronde flows terminated midway into the basin to begin the formation of a topographic high that now separates a thick sediment wedge of the Vantage Member to the east of the high from a thin layer to the west. Disrupted by lava flows, streams were pushed from a west-flowing direction to a north-northwest orientation and drained the basin through a gap between steptoes toward Palouse, Washington. Emplacement of the Roza flow of the Wanapum Basalt against the western side of the topographic high was instrumental in this process, plugging west-flowing drainages and increasing deposition of Vantage sediments east of the high. The overlying basalt of Lolo covered both the Roza flow and Vantage sediments, blocking all drainages, and was in turn covered by sediments interlayered with local Saddle Mountains Basalt flows. Reestablishment of west-flowing drainages has been slow.The uppermost Grande Ronde, the Vantage, and the Wanapum contain what is known as the upper aquifer. The water supply is controlled, in part, by thickness, composition, and distribution of the Vantage sediments. A buried channel of the Vantage likely connects the upper aquifer to Palouse, Washington, outside the basin. This field guide locates outcrops; relates them to

  18. Hall effect in noncommutative coordinates

    International Nuclear Information System (INIS)

    Dayi, Oemer F.; Jellal, Ahmed

    2002-01-01

    We consider electrons in uniform external magnetic and electric fields which move on a plane whose coordinates are noncommuting. Spectrum and eigenfunctions of the related Hamiltonian are obtained. We derive the electric current whose expectation value gives the Hall effect in terms of an effective magnetic field. We present a receipt to find the action which can be utilized in path integrals for noncommuting coordinates. In terms of this action we calculate the related Aharonov-Bohm phase and show that it also yields the same effective magnetic field. When magnetic field is strong enough this phase becomes independent of magnetic field. Measurement of it may give some hints on spatial noncommutativity. The noncommutativity parameter θ can be tuned such that electrons moving in noncommutative coordinates are interpreted as either leading to the fractional quantum Hall effect or composite fermions in the usual coordinates

  19. General vibration monitoring: Experimental hall

    International Nuclear Information System (INIS)

    Jendrzejczyk, J.A.; Wambsganss, M.W.; Smith, R.K.

    1993-01-01

    The reported vibration data were generated from measurements made on the experimental hall floor on December 2, 1992. At the time of the measurements, the ESRF hydrolevel was set-up in the Early Assembly Area (EAA) of the experimental hall and was being used to measure static displacement (settlement) of the floor. The vibration measurement area was on and adjacent to the EAA, in the vicinity of the ESRF hydrolevel test which was in progress. This report summarizes the objectives, instrumentation, measurement locations, observations, and conclusions, and provides selected results in the form of RMS vs. time plots, and power spectral densities from which frequency information can be derived. Measured response amplitudes were within the vibration criteria established for the APS

  20. Scanning vector Hall probe microscope

    Czech Academy of Sciences Publication Activity Database

    Fedor, J.; Cambel, V.; Gregušová, D.; Hanzelka, Pavel; Dérer, J.; Volko, J.

    2003-01-01

    Roč. 74, č. 12 (2003), s. 5105 - 5110 ISSN 0034-6748 Institutional research plan: CEZ:AV0Z2065902 Keywords : VHPM * Hall sensor * Helium cryostat Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.343, year: 2003 http://web. ebscohost .com/ehost/pdf?vid=8&hid=115&sid=a7c0555a-21f4-4932-b1c6-a308ac4dd50b%40sessionmgr2

  1. Spike-adding in parabolic bursters: The role of folded-saddle canards

    Science.gov (United States)

    Desroches, Mathieu; Krupa, Martin; Rodrigues, Serafim

    2016-09-01

    The present work develops a new approach to studying parabolic bursting, and also proposes a novel four-dimensional canonical and polynomial-based parabolic burster. In addition to this new polynomial system, we also consider the conductance-based model of the Aplysia R15 neuron known as the Plant model, and a reduction of this prototypical biophysical parabolic burster to three variables, including one phase variable, namely the Baer-Rinzel-Carillo (BRC) phase model. Revisiting these models from the perspective of slow-fast dynamics reveals that the number of spikes per burst may vary upon parameter changes, however the spike-adding process occurs in an explosive fashion that involves special solutions called canards. This spike-adding canard explosion phenomenon is analysed by using tools from geometric singular perturbation theory in tandem with numerical bifurcation techniques. We find that the bifurcation structure persists across all considered systems, that is, spikes within the burst are incremented via the crossing of an excitability threshold given by a particular type of canard orbit, namely the true canard of a folded-saddle singularity. However there can be a difference in the spike-adding transitions in parameter space from one case to another, according to whether the process is continuous or discontinuous, which depends upon the geometry of the folded-saddle canard. Using these findings, we construct a new polynomial approximation of the Plant model, which retains all the key elements for parabolic bursting, including the spike-adding transitions mediated by folded-saddle canards. Finally, we briefly investigate the presence of spike-adding via canards in planar phase models of parabolic bursting, namely the theta model by Ermentrout and Kopell.

  2. Flood-inundation maps for the Saddle River from Rochelle Park to Lodi, New Jersey, 2012

    Science.gov (United States)

    Hoppe, Heidi L.; Watson, Kara M.

    2012-01-01

    Digital flood-inundation maps for a 2.75-mile reach of the Saddle River from 0.2 mile upstream from the Interstate 80 bridge in Rochelle Park to 1.5 miles downstream from the U.S. Route 46 bridge in Lodi, New Jersey, were created by the U.S. Geological Survey (USGS) in cooperation with the New Jersey Department of Environmental Protection (NJDEP). The inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage at Saddle River at Lodi, New Jersey (station 01391500). Current conditions for estimating near real-time areas of inundation using USGS streamgage information may be obtained on the Internet at http://waterdata.usgs.gov/nwis/uv?site_no=01391500. The National Weather Service (NWS) forecasts flood hydrographs at many places that are often collocated with USGS streamgages. NWS-forecasted peak-stage information may be used in conjunction with the maps developed in this study to show predicted areas of flood inundation. In this study, flood profiles were computed for the stream reach by means of a one-dimensional step-backwater model. The model was calibrated using the most current stage-discharge relations at the Saddle River at Lodi, New Jersey streamgage and documented high-water marks from recent floods. The hydraulic model was then used to determine 11 water-surface profiles for flood stages at the Saddle River streamgage at 1-ft intervals referenced to the streamgage datum, North American Vertical Datum of 1988 (NAVD 88), and ranging from bankfull, 0.5 ft below NWS Action Stage, to the extent of the stage-discharge rating, which is approximately 1 ft higher than the highest recorded water level at the streamgage. Action Stage is the stage which when reached by a rising stream the NWS or a partner needs to take some type of mitigation action in

  3. On preconditioner updates for sequences of saddle-point linear systems

    Directory of Open Access Journals (Sweden)

    Simone Valentina De

    2018-02-01

    Full Text Available Updating preconditioners for the solution of sequences of large and sparse saddle- point linear systems via Krylov methods has received increasing attention in the last few years, because it allows to reduce the cost of preconditioning while keeping the efficiency of the overall solution process. This paper provides a short survey of the two approaches proposed in the literature for this problem: updating the factors of a preconditioner available in a block LDLT form, and updating a preconditioner via a limited-memory technique inspired by quasi-Newton methods.

  4. Determination of shell correction energies at saddle point using pre-scission neutron multiplicities

    International Nuclear Information System (INIS)

    Golda, K.S.; Saxena, A.; Mittal, V.K.; Mahata, K.; Sugathan, P.; Jhingan, A.; Singh, V.; Sandal, R.; Goyal, S.; Gehlot, J.; Dhal, A.; Behera, B.R.; Bhowmik, R.K.; Kailas, S.

    2013-01-01

    Pre-scission neutron multiplicities have been measured for 12 C + 194, 198 Pt systems at matching excitation energies at near Coulomb barrier region. Statistical model analysis with a modified fission barrier and level density prescription have been carried out to fit the measured pre-scission neutron multiplicities and the available evaporation residue and fission cross sections simultaneously to constrain statistical model parameters. Simultaneous fitting of the pre-scission neutron multiplicities and cross section data requires shell correction at the saddle point

  5. Conjugate gradient filtering of instantaneous normal modes, saddles on the energy landscape, and diffusion in liquids.

    Science.gov (United States)

    Chowdhary, J; Keyes, T

    2002-02-01

    Instantaneous normal modes (INM's) are calculated during a conjugate-gradient (CG) descent of the potential energy landscape, starting from an equilibrium configuration of a liquid or crystal. A small number (approximately equal to 4) of CG steps removes all the Im-omega modes in the crystal and leaves the liquid with diffusive Im-omega which accurately represent the self-diffusion constant D. Conjugate gradient filtering appears to be a promising method, applicable to any system, of obtaining diffusive modes and facilitating INM theory of D. The relation of the CG-step dependent INM quantities to the landscape and its saddles is discussed.

  6. Controlling Unknown Saddle Type Steady States of Dynamical Systems with Latency in the Feedback Loop

    DEFF Research Database (Denmark)

    Tamasevicius, Arunas; Bumeliene, Skaidra; Tamaseviciute, Elena

    2009-01-01

    We suggest an adaptive control technique for stabilizing saddle type unstable steady states of dynamical systems. The controller is composed of an unstable and a stable high-pass filters operating in parallel. The mathematical model is considered analytically and numerically. The conjoint...... controller is sufficiently robust to time latencies in the feedback loop. In addition, it is not sensitive to the damping parameters of the system and is relatively fast. Experiments have been performed using a simplified version of the electronic Young-Silva circuit imitating behavior of the Duffing...

  7. Approximate Dual Averaging Method for Multiagent Saddle-Point Problems with Stochastic Subgradients

    Directory of Open Access Journals (Sweden)

    Deming Yuan

    2014-01-01

    Full Text Available This paper considers the problem of solving the saddle-point problem over a network, which consists of multiple interacting agents. The global objective function of the problem is a combination of local convex-concave functions, each of which is only available to one agent. Our main focus is on the case where the projection steps are calculated approximately and the subgradients are corrupted by some stochastic noises. We propose an approximate version of the standard dual averaging method and show that the standard convergence rate is preserved, provided that the projection errors decrease at some appropriate rate and the noises are zero-mean and have bounded variance.

  8. Paleoseismic evidence for late Holocene tectonic deformation along the Saddle mountain fault zone, Southeastern Olympic Peninsula, Washington

    Science.gov (United States)

    Barnett, Elizabeth; Sherrod, Brian; Hughes, Jonathan F.; Kelsey, Harvey M.; Czajkowski, Jessica L.; Walsh, Timothy J.; Contreras, Trevor A.; Schermer, Elizabeth R.; Carson, Robert J.

    2015-01-01

    Trench and wetland coring studies show that northeast‐striking strands of the Saddle Mountain fault zone ruptured the ground about 1000 years ago, generating prominent scarps. Three conspicuous subparallel fault scarps can be traced for 15 km on Light Detection and Ranging (LiDAR) imagery, traversing the foothills of the southeast Olympic Mountains: the Saddle Mountain east fault, the Saddle Mountain west fault, and the newly identified Sund Creek fault. Uplift of the Saddle Mountain east fault scarp impounded stream flow, forming Price Lake and submerging an existing forest, thereby leaving drowned stumps still rooted in place. Stratigraphy mapped in two trenches, one across the Saddle Mountain east fault and the other across the Sund Creek fault, records one and two earthquakes, respectively, as faulting juxtaposed Miocene‐age bedrock against glacial and postglacial deposits. Although the stratigraphy demonstrates that reverse motion generated the scarps, slip indicators measured on fault surfaces suggest a component of left‐lateral slip. From trench exposures, we estimate the postglacial slip rate to be 0.2  mm/yr and between 0.7 and 3.2  mm/yr during the past 3000 years. Integrating radiocarbon data from this study with earlier Saddle Mountain fault studies into an OxCal Bayesian statistical chronology model constrains the most recent paleoearthquake age of rupture across all three Saddle Mountain faults to 1170–970 calibrated years (cal B.P.), which overlaps with the nearby Mw 7.5 1050–1020 cal B.P. Seattle fault earthquake. An earlier earthquake recorded in the Sund Creek trench exposure, dates to around 3500 cal B.P. The geometry of the Saddle Mountain faults and their near‐synchronous rupture to nearby faults 1000 years ago suggest that the Saddle Mountain fault zone forms a western boundary fault along which the fore‐arc blocks migrate northward in response to margin‐parallel shortening across the Puget Lowland.

  9. The effectiveness of adhesives on the retention of mandibular free end saddle partial dentures: An in vitro study.

    Science.gov (United States)

    Quiney, Daniel; Nishio Ayre, Wayne; Milward, Paul

    2017-07-01

    Existing in vitro methods for testing denture adhesives do not fully replicate the complex oral geometries and environment; and in vivo methods are qualitative, prone to bias and not easily reproducible. The purpose of this study was to develop a novel, quantitative and more accurate model to test the effect of adhesives on the retentive force of mandibular free end saddle partial dentures. An in vitro model was developed based on an anatomically accurate cast of a clinical case. Experimentally, the amount of adhesive was varied (0.2g-1g) and the tensile force required for displacement was measured. Different commercially available adhesives were then tested at the optimum volume using the in vitro model. A 3D finite element model of the denture was used to assess how the forces to induce denture displacement varied according to the position of the force along the saddle length. The mass of adhesive was found to significantly alter retention forces, with 0.4-0.7g being the optimum range for this particular scenario. Use of adhesives significantly improved mandibular free end saddle partial denture retention with the worst performing adhesive increasing retention nine-fold whilst the best performing adhesive increased retention twenty three-fold. The finite element model revealed that 77% more force was required to displace the denture by positioning forces towards the mesial end of the saddle compared to the distal end. An in vitro denture adhesive model was developed, which demonstrated that mass of adhesive plays a significant role in enhancing denture retention and supported the design principle of placing as few teeth as clinically necessary on the distal end of the free end saddles. Limiting the position of teeth on free end saddles to the mesial and mid portion of the saddle will reduce displacements caused by mastication. The movement of mandibular free end saddle partial dentures can be restricted with the use of denture adhesives. Altering the mass of

  10. L'effet Hall Quantique

    Science.gov (United States)

    Samson, Thomas

    Nous proposons une methode permettant d'obtenir une expression pour la conductivite de Hall de structures electroniques bidimensionnelles et nous examinons celle -ci a la limite d'une temperature nulle dans le but de verifier l'effet Hall quantique. Nous allons nous interesser essentiellement a l'effet Hall quantique entier et aux effets fractionnaires inferieurs a un. Le systeme considere est forme d'un gaz d'electrons en interaction faible avec les impuretes de l'echantillon. Le modele du gaz d'electrons consiste en un gaz bidimensionnel d'electrons sans spin expose perpendiculairement a un champ magnetique uniforme. Ce dernier est decrit par le potentiel vecteur vec{rm A} defini dans la jauge de Dingle ou jauge symetrique. Conformement au formalisme de la seconde quantification, l'hamiltonien de ce gaz est represente dans la base des etats a un-corps de Dingle |n,m> et exprime ainsi en terme des operateurs de creation et d'annihilation correspondants a_sp{ rm n m}{dag} et a _{rm n m}. Nous supposons de plus que les electrons du niveau fondamental de Dingle interagissent entre eux via le potentiel coulombien. La methode utilisee fait appel a une equation mai tresse a N-corps, de nature quantique et statistique, et verifiant le second principe de la thermodynamique. A partir de celle-ci, nous obtenons un systeme d'equations differentielles appele hierarchie d'equations quantique dont la resolution nous permet de determiner une equation a un-corps, dite de Boltzmann quantique, et dictant l'evolution de la moyenne statistique de l'operateur non-diagonal a _sp{rm n m}{dag } a_{rm n}, _{rm m}, sous l'action du champ electrique applique vec{rm E}(t). C'est sa solution Tr(p(t) a _sp{rm n m}{dag} a_{rm n},_ {rm m}), qui definit la relation de convolution entre la densite courant de Hall vec{rm J}_{rm H }(t) et le champ electrique vec {rm E}(t) dont la transformee de Laplace-Fourier du noyau nous fournit l'expression de la conductivite de Hall desiree. Pour une valeur de

  11. Spin Hall effect by surface roughness

    KAUST Repository

    Zhou, Lingjun

    2015-01-08

    The spin Hall and its inverse effects, driven by the spin orbit interaction, provide an interconversion mechanism between spin and charge currents. Since the spin Hall effect generates and manipulates spin current electrically, to achieve a large effect is becoming an important topic in both academia and industries. So far, materials with heavy elements carrying a strong spin orbit interaction, provide the only option. We propose here a new mechanism, using the surface roughness in ultrathin films, to enhance the spin Hall effect without heavy elements. Our analysis based on Cu and Al thin films suggests that surface roughness is capable of driving a spin Hall angle that is comparable to that in bulk Au. We also demonstrate that the spin Hall effect induced by surface roughness subscribes only to the side-jump contribution but not the skew scattering. The paradigm proposed in this paper provides the second, not if only, alternative to generate a sizable spin Hall effect.

  12. Tunneling Anomalous and Spin Hall Effects.

    Science.gov (United States)

    Matos-Abiague, A; Fabian, J

    2015-07-31

    We predict, theoretically, the existence of the anomalous Hall effect when a tunneling current flows through a tunnel junction in which only one of the electrodes is magnetic. The interfacial spin-orbit coupling present in the barrier region induces a spin-dependent momentum filtering in the directions perpendicular to the tunneling current, resulting in a skew tunneling even in the absence of impurities. This produces an anomalous Hall conductance and spin Hall currents in the nonmagnetic electrode when a bias voltage is applied across the tunneling heterojunction. If the barrier is composed of a noncentrosymmetric material, the anomalous Hall conductance and spin Hall currents become anisotropic with respect to both the magnetization and crystallographic directions, allowing us to separate this interfacial phenomenon from the bulk anomalous and spin Hall contributions. The proposed effect should be useful for proving and quantifying the interfacial spin-orbit fields in metallic and metal-semiconductor systems.

  13. On the late-time behavior of Virasoro blocks and a classification of semiclassical saddles

    Energy Technology Data Exchange (ETDEWEB)

    Fitzpatrick, A. Liam [Department of Physics, Boston University,Commonwealth Avenue, Boston, MA 02215 (United States); Kaplan, Jared [Department of Physics and Astronomy, Johns Hopkins University,Charles Street, Baltimore, MD 21218 (United States)

    2017-04-12

    Recent work has demonstrated that black hole thermodynamics and information loss/restoration in AdS{sub 3}/CFT{sub 2} can be derived almost entirely from the behavior of the Virasoro conformal blocks at large central charge, with relatively little dependence on the precise details of the CFT spectrum or OPE coefficients. Here, we elaborate on the non-perturbative behavior of Virasoro blocks by classifying all ‘saddles’ that can contribute for arbitrary values of external and internal operator dimensions in the semiclassical large central charge limit. The leading saddles, which determine the naive semiclassical behavior of the Virasoro blocks, all decay exponentially at late times, and at a rate that is independent of internal operator dimensions. Consequently, the semiclassical contribution of a finite number of high-energy states cannot resolve a well-known version of the information loss problem in AdS{sub 3}. However, we identify two infinite classes of sub-leading saddles, and one of these classes does not decay at late times.

  14. Observation of the Zero Hall Plateau in a Quantum Anomalous Hall Insulator

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Yang; Feng, Xiao; Ou, Yunbo; Wang, Jing; Liu, Chang; Zhang, Liguo; Zhao, Dongyang; Jiang, Gaoyuan; Zhang, Shou-Cheng; He, Ke; Ma, Xucun; Xue, Qi-Kun; Wang, Yayu

    2015-09-16

    We report experimental investigations on the quantum phase transition between the two opposite Hall plateaus of a quantum anomalous Hall insulator. We observe a well-defined plateau with zero Hall conductivity over a range of magnetic field around coercivity when the magnetization reverses. The features of the zero Hall plateau are shown to be closely related to that of the quantum anomalous Hall effect, but its temperature evolution exhibits a significant difference from the network model for a conventional quantum Hall plateau transition. We propose that the chiral edge states residing at the magnetic domain boundaries, which are unique to a quantum anomalous Hall insulator, are responsible for the novel features of the zero Hall plateau.

  15. Anomalous Hall effect in polycrystalline Ni films

    KAUST Repository

    Guo, Zaibing

    2012-02-01

    We systematically studied the anomalous Hall effect in a series of polycrystalline Ni films with thickness ranging from 4 to 200 nm. It is found that both the longitudinal and anomalous Hall resistivity increased greatly as film thickness decreased. This enhancement should be related to the surface scattering. In the ultrathin films (46 nm thick), weak localization corrections to anomalous Hall conductivity were studied. The granular model, taking into account the dominated intergranular tunneling, has been employed to explain this phenomenon, which can explain the weak dependence of anomalous Hall resistivity on longitudinal resistivity as well. © 2011 Elsevier Ltd. All rights reserved.

  16. Temperature Gradient in Hall Thrusters

    International Nuclear Information System (INIS)

    Staack, D.; Raitses, Y.; Fisch, N.J.

    2003-01-01

    Plasma potentials and electron temperatures were deduced from emissive and cold floating probe measurements in a 2 kW Hall thruster, operated in the discharge voltage range of 200-400 V. An almost linear dependence of the electron temperature on the plasma potential was observed in the acceleration region of the thruster both inside and outside the thruster. This result calls into question whether secondary electron emission from the ceramic channel walls plays a significant role in electron energy balance. The proportionality factor between the axial electron temperature gradient and the electric field is significantly smaller than might be expected by models employing Ohmic heating of electrons

  17. 75 FR 7467 - Gary E. Hall and Rita C. Hall; Notice of Application Accepted for Filing With the Commision...

    Science.gov (United States)

    2010-02-19

    ... Rita C. Hall; Notice of Application Accepted for Filing With the Commision, Soliciting Motions To.... Project No.: 13652-000. c. Date filed: January 11, 2010. d. Applicant: Gary E. Hall and Rita C. Hall. e... Policies Act of 1978, 16 U.S.C. 2705, 2708. h. Applicant Contact: Mr. Gary E. Hall and Ms. Rita C. Hall, P...

  18. Nondestructive hall coefficient measurements using ACPD techniques

    Science.gov (United States)

    Velicheti, Dheeraj; Nagy, Peter B.; Hassan, Waled

    2018-04-01

    Hall coefficient measurements offer great opportunities as well as major challenges for nondestructive materials characterization. The Hall effect is produced by the magnetic Lorentz force acting on moving charge carriers in the presence of an applied magnetic field. The magnetic perturbation gives rise to a Hall current that is normal to the conduction current but does not directly perturb the electric potential distribution. Therefore, Hall coefficient measurements usually exploit the so-called transverse galvanomagnetic potential drop effect that arises when the Hall current is intercepted by the boundaries of the specimen and thereby produce a measurable potential drop. In contrast, no Hall potential is produced in a large plate in the presence of a uniform normal field at quasi-static low frequencies. In other words, conventional Hall coefficient measurements are inherently destructive since they require cutting the material under tests. This study investigated the feasibility of using alternating current potential drop (ACPD) techniques for nondestructive Hall coefficient measurements in plates. Specifically, the directional four-point square-electrode configuration is investigated with superimposed external magnetic field. Two methods are suggested to make Hall coefficient measurements in large plates without destructive machining. At low frequencies, constraining the bias magnetic field can replace constraining the dimensions of the specimen, which is inherently destructive. For example, when a cylindrical permanent magnet is used to provide the bias magnetic field, the peak Hall voltage is produced when the diameter of the magnet is equal to the diagonal of the square ACPD probe. Although this method is less effective than cutting the specimen to a finite size, the loss of sensitivity is less than one order of magnitude even at very low frequencies. In contrast, at sufficiently high inspection frequencies the magnetic field of the Hall current induces a

  19. Hall magnetohydrodynamics of neutral layers

    International Nuclear Information System (INIS)

    Huba, J.D.; Rudakov, L.I.

    2003-01-01

    New analytical and numerical results of the dynamics of inhomogeneous, reversed field current layers in the Hall limit (i.e., characteristic length scales < or approx. the ion inertial length) are presented. Specifically, the two- and three-dimensional evolution of a current layer that supports a reversed field plasma configuration and has a density gradient along the current direction is studied. The two-dimensional study demonstrates that a density inhomogeneity along the current direction can dramatically redistribute the magnetic field and plasma via magnetic shock-like or rarefaction waves. The relative direction between the density gradient and current flow plays a critical role in the evolution of the current sheet. One important result is that the current sheet can become very thin rapidly when the density gradient is directed opposite to the current. The three-dimensional study uses the same plasma and field configuration as the two-dimensional study but is also initialized with a magnetic field perturbation localized along the current channel upstream of the plasma inhomogeneity. The perturbation induces a magnetic wave structure that propagates in the direction of the electron drift (i.e., opposite to the current). The propagating wave structure is a Hall phenomenon associated with magnetic field curvature. The interaction between the propagating wave structure and the evolving current layer can lead to rapid magnetic field line reconnection. The results are applied to laboratory and space plasma processes

  20. Effects of saddle height on economy and anaerobic power in well-trained cyclists.

    Science.gov (United States)

    Peveler, Willard W; Green, James M

    2011-03-01

    In cycling, saddle height adjustment is critical for optimal performance and injury prevention. A 25-35° knee angle is recommended for injury prevention, whereas 109% of inseam, measured from floor to ischium, is recommended for optimal performance. Previous research has demonstrated that these 2 methods produce significantly different saddle heights and may influence cycling performance. This study compared performance between these 2 methods for determining saddle height. Subjects consisted of 11 well-trained (VO2max = 61.55 ± 4.72 ml·kg·min) male cyclists. Subjects completed a total of 8 performance trials consisting of a graded maximal protocol, three 15-minute economy trials, and 4 anaerobic power trials. Dependent measures for economy (VO2, heart rate, and rating of perceived exertion) and anaerobic power (peak power and mean power) were compared using repeated measures analysis of variance (α = 0.05). VO2 was significantly lower (reflecting greater economy) at a 25° knee angle (44.77 ± 6.40 ml·kg·min) in comparison to a 35° knee angle (45.22 ± 6.79 ml·kg·min) and 109% of inseam (45.98 ± 5.33 ml·kg·min). Peak power at a 25° knee angle (1,041.55 ± 168.72 W) was significantly higher in relation to 109% of inseam (1,002.05 ± 147.65 W). Mean power at a 25° knee angle (672.37 ± 90.21 W) was significantly higher in relation to a 35° knee angle (654.71 ± 80.67 W). Mean power was significantly higher at 109% of inseam (662.86 ± 79.72 W) in relation to a 35° knee angle (654.71 ± 80.67 W). Use of 109% of inseam fell outside the recommended 25-35° range 73% of the time. Use of 25° knee angle appears to provide optimal performance while keeping knee angle within the recommended range for injury prevention.

  1. Identification of a mutation that is associated with the saddle tan and black-and-tan phenotypes in Basset Hounds and Pembroke Welsh Corgis.

    Science.gov (United States)

    Dreger, Dayna L; Parker, Heidi G; Ostrander, Elaine A; Schmutz, Sheila M

    2013-01-01

    The causative mutation for the black-and-tan (a (t) ) phenotype in dogs was previously shown to be a SINE insertion in the 5' region of Agouti Signaling Protein (ASIP). Dogs with the black-and-tan phenotype, as well as dogs with the saddle tan phenotype, genotype as a (t) /_ at this locus. We have identified a 16-bp duplication (g.1875_1890dupCCCCAGGTCAGAGTTT) in an intron of hnRNP associated with lethal yellow (RALY), which segregates with the black-and-tan phenotype in a group of 99 saddle tan and black-and-tan Basset Hounds and Pembroke Welsh Corgis. In these breeds, all dogs with the saddle tan phenotype had RALY genotypes of +/+ or +/dup, whereas dogs with the black-and-tan phenotype were homozygous for the duplication. The presence of an a (y) /_ fawn or e/e red genotype is epistatic to the +/_ saddle tan genotype. Genotypes from 10 wolves and 1 coyote indicated that the saddle tan (+) allele is the ancestral allele, suggesting that black-and-tan is a modification of saddle tan. An additional 95 dogs from breeds that never have the saddle tan phenotype have all three of the possible RALY genotypes. We suggest that a multi-gene interaction involving ASIP, RALY, MC1R, DEFB103, and a yet-unidentified modifier gene is required for expression of saddle tan.

  2. Quantum Hall effect in quantum electrodynamics

    International Nuclear Information System (INIS)

    Penin, Alexander A.

    2009-01-01

    We consider the quantum Hall effect in quantum electrodynamics and find a deviation from the quantum-mechanical prediction for the Hall conductivity due to radiative antiscreening of electric charge in an external magnetic field. A weak dependence of the universal von Klitzing constant on the magnetic field strength, which can possibly be observed in a dedicated experiment, is predicted

  3. Hall devices improve electric motor efficiency

    Science.gov (United States)

    Haeussermann, W.

    1979-01-01

    Efficiency of electric motors and generators is reduced by radial magnetic forces created by symmetric fields within device. Forces are sensed and counteracted by Hall devices on excitation or control windings. Hall generators directly measure and provide compensating control of anu asymmetry, eliminating additional measurements needed for calibration feedback control loop.

  4. Higher fractions theory of fractional hall effect

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.; Popov, V.N.

    1985-07-01

    A theory of fractional quantum Hall effect is generalized to higher fractions. N-particle model interaction is used and the gap is expressed through n-particles wave function. The excitation spectrum in general and the mean field critical behaviour are determined. The Hall conductivity is calculated from first principles. (author)

  5. Compound nucleus decay: Comparison between saddle point and scission point barriers

    Energy Technology Data Exchange (ETDEWEB)

    Santos, T. J.; Carlson, B. V. [Depto. de Física, Instituto Tecnológico de Aeronáutica, São José dos Campos, SP (Brazil)

    2014-11-11

    One of the principal characteristics of nuclear multifragmentation is the emission of complex fragments of intermediate mass. An extension of the statistical multifragmentation model has been developed, in which the process can be interpreted as the near simultaneous limit of a series of sequential binary decays. In this extension, intermediate mass fragment emissions are described by expressions almost identical to those of light particle emission. At lower temperatures, similar expressions have been shown to furnish a good description of very light intermediate mass fragment emission but not of the emission of heavier fragments, which seems to be determined by the transition density at the saddle-point rather than at the scission point. Here, we wish to compare these different formulations of intermediate fragmment emission and analyze the extent to which they remain distinguishable at high excitation energy.

  6. A saddle-point for data verification and materials accountancy to control nuclear material

    International Nuclear Information System (INIS)

    Beedgen, R.

    1983-01-01

    Materials accountancy is one of the main elements in international safeguards to determine whether or not nuclear material has been diverted in nuclear plants. The inspector makes independent measurements to verify the plant-operator's data before closing the materials balance with the operator's data. All inspection statements are in principle probability statements because of random errors in measuring the material and verification on a random sampling basis. Statistical test procedures help the inspector to decide under this uncertainty. In this paper a statistical test procedure representing a saddle-point is presented that leads to the highest guaranteed detection probability taking all concealing strategies into account. There are arguments favoring a separate statistical evaluation of data verification and materials accountancy. Following these considerations, a bivariate test procedure is explained that evaluates verification and accountancy separately. (orig.) [de

  7. Environmental records from temperate glacier ice on Nevado Coropuna saddle, southern Peru

    Directory of Open Access Journals (Sweden)

    J. Herreros

    2009-10-01

    Full Text Available We investigated past climate variability and the zonal short and long-range transport of air masses in tropical South America using chemical, isotopic and palynological signals from a 42 m-long ice core recovered in 2003 from the saddle of the Nevado Coropuna, southern Peru (72°39´ W; 15°32´ S; 6080 m a.s.l.. We found that precipitation at this site depends mainly on the easterly circulation of air masses originated from the tropical Atlantic Ocean. Nevertheless, sporadic Pacific air masses arrivals, and strong cold waves coming from southern South America reach this altitude site. In spite of post-depositional effects, we were able to identify two strong ENSO (El Niño-Southern Oscillation event signatures (1982–1983 and 1992 and the eruptive activity of the nearby Sabancaya volcano (1994.

  8. Computing closest saddle node bifurcations in a radial system via conic programming

    Energy Technology Data Exchange (ETDEWEB)

    Jabr, R.A. [Electrical, Computer and Communication Engineering Department, Notre Dame University, P.O. Box 72, Zouk Mikhael, Zouk Mosbeh (Lebanon); Pal, B.C. [Department of Electrical and Electronic Engineering, Imperial College London, SW7 2BT (United Kingdom)

    2009-07-15

    This paper considers the problem of computing the loading limits in a radial system which are (i) locally closest to current operating load powers and (ii) at which saddle node bifurcation occurs. The procedure is based on a known technique which requires iterating between two computational steps until convergence. In essence, step 1 produces a vector normal to the real and/or reactive load solution space boundary, whereas step 2 computes the bifurcation point along that vector. The paper shows that each of the above computational steps can be formulated as a second-order cone program for which polynomial time interior-point methods and efficient implementations exist. The proposed conic programming approach is used to compute the closest bifurcation points and the corresponding worst case load power margins of eleven different distribution systems. The approach is validated graphically and the existence of multiple load power margins is investigated. (author)

  9. THz-waves channeling in a monolithic saddle-coil for Dynamic Nuclear Polarization enhanced NMR

    Science.gov (United States)

    Macor, A.; de Rijk, E.; Annino, G.; Alberti, S.; Ansermet, J.-Ph.

    2011-10-01

    A saddle coil manufactured by electric discharge machining (EDM) from a solid piece of copper has recently been realized at EPFL for Dynamic Nuclear Polarization enhanced Nuclear Magnetic Resonance experiments (DNP-NMR) at 9.4 T. The corresponding electromagnetic behavior of radio-frequency (400 MHz) and THz (263 GHz) waves were studied by numerical simulation in various measurement configurations. Moreover, we present an experimental method by which the results of the THz-wave numerical modeling are validated. On the basis of the good agreement between numerical and experimental results, we conducted by numerical simulation a systematic analysis on the influence of the coil geometry and of the sample properties on the THz-wave field, which is crucial in view of the optimization of DNP-NMR in solids.

  10. Saddle-splay elasticity of nematic structures confined to a cylindrical capillary

    International Nuclear Information System (INIS)

    Kralj, S.; Zumer, S.

    1995-01-01

    The stability of nematic structures within a cylindrical capillary whose wall exhibits a homeotropic boundary condition is studied. The structures are obtained numerically from Euler-Lagrange equations resulting from the minimization of the Frank free energy functional. Stability diagrams are presented showing dependence on elastic properties, surface anchoring, and external transversal field strength. Emphasis is given to the effects of the saddle-splay elastic constant (K 24 ), which plays an important role in the weak anchoring regime. A new structure---the planar polar structure with two line defects---is predicted. It is shown that it is stable in a finite interval of the external field strength in the strong anchoring regime

  11. Report of experimental hall subworking group

    International Nuclear Information System (INIS)

    Miyake, K.; Ohama, T.; Takahashi, K.

    1982-01-01

    The general plan of constructing the TRISTAN e + e - colliding beam experimental halls may be divided into two parts. The first step is to construct two test-experimental halls associated with the 6.5 GeV x 6.5 GeV e + e - accumulator ring, and the second step is to build four experimental halls at the 30 GeV x 30 GeV e + e - TRISTAN main ring. At this workshop, extensive discussions on the detailed design of the four main ring experimental halls have been made. Four experimental areas will be built at the main ring, and two test-experimental halls at the accumulating ring. Among the four areas at the main ring, two will be used for electron-proton possible as well as electron-positron colliding beam experiment. The other two will be used exclusively for e + e - colliding experiments. Only a preliminary design has been made for these four experimental areas. A tentative plan of a larger experimental hall includes a counting and data processing room, a utility room, and a radiation safety control room. Two smaller halls have simpler structure. The figures of the experimental halls are presented. The two test-experimental halls at the accumulator ring will be used to test the detectors for e + e - colliding experiments before the final installation. The utility rooms designed for the halls are used to supply coolant and electric power of superconducting magnets. At the workshop, various ideas concerning the preliminary plan are presented. (Kato, T.)

  12. Classical generalized transition-state theory. Application to a collinear reaction with two saddle points

    International Nuclear Information System (INIS)

    Garrett, B.C.; Truhlar, D.G.; Grev, R.S.

    1981-01-01

    Accurate classical dynamical fixed-energy reaction probabilities and fixed-temperature rate constants are calculated for the collinear reaction H + FH on a low-barrier model potential energy surface. The calculations cover energies from 0.1 to 100 kcal/mol above threshold and temperatures of 100 to 10,000 K. The accurate results are used to test five approximate theories: conventional transition-state theory (TST), canonical variational theory (CVT), improved canonical variational theory (ICVT), microcanonical variational theory (μVT), and the unified statistical model (US). The first four of these theories involve a single dividing surface in phase space, and the US theory involves three dividing surfaces. The tests are particularly interesting because the potential energy surface has two identical saddle points. At temperatures from 100 to 2000 K, the μVt is the most accurate theory, with errors in the range 11 to 14%; for temperatures from 2000 to 10,000 K, the US theory is the most successful, with errors in the range 3 to 14%. Over the whole range, a factor of 100 in temperature, both theories have errors of 35% or less. Even TST has errors of 47% or less over the whole factor-of-100 temperature range. Although the US model should become exact at threshold for this system, it already underestimates the reaction probability by a factor of 0.64 at 0.1 kcal/mol above threshold. TST and μVT agree with each other within 12% up to an energy 13 kcal/mol above the saddle point energy. 3 figures, 2 tables

  13. Electrical design of the BUSSARD inverter system for ASDEX upgrade saddle coils

    Energy Technology Data Exchange (ETDEWEB)

    Teschke, Markus, E-mail: teschke@ipp.mpg.de; Arden, Nils; Eixenberger, Horst; Rott, Michael; Suttrop, Wolfgang

    2015-10-15

    Highlights: • A cost effective inverter topology for AUG's 16 in-vessel saddle coils has been found. • Use of commercially available power modules is possible. • A NPC-like topology of the power stage is realized in a modular way. • The high-speed controllers and PWM engines are realized on Linux-based systems. • First experimental results of AUG plasma shots are presented. - Abstract: A set of 16 in-vessel saddle coils is installed in the ASDEX Upgrade (AUG) nuclear fusion experiment for mitigation of edge localized modes (ELM) and feedback control of resistive wall modes (RWM). The coils were driven by DC current only during previous campaigns. Now, a new inverter system “BUSSARD” (German abbr. for “Bayerischer Umrichter, schnell schaltend für AUGs rasche Drehfelder”, translated: “bavarian fast switching inverter for AUG's fast rotating fields”) is built for the experiment. A four-phase system has been assembled to simultaneously operate up to 4 groups of coils consisting of up to 4 serial-connected coils each. The maximum current is 1.3 kA with a ripple in the range of 7% and the frequency is variable between DC and approx. 100 Hz. The switching frequency is variable between approximately 3 and 10 kHz. As a first application, rotating fields are generated. The system can be enhanced in two stages to 16-phase operation with a bandwidth of 500 Hz and a 24 phase system with a bandwidth of up to 3 kHz.

  14. Regional anesthesia in transurethral resection of prostate (TURP surgery: A comparative study between saddle block and subarachnoid block

    Directory of Open Access Journals (Sweden)

    Susmita Bhattacharyya

    2015-01-01

    Full Text Available Background: Spinal anesthesia is the technique of choice in transurethral resection of prostate (TURP. The major complication of spinal technique is risk of hypotension. Saddle block paralyzed pelvic muscles and sacral nerve roots and hemodynamic derangement is less. Aims and objectives: To compare the hemodynamic changes and adequate surgical condition between saddle block and subarachnoid block for TURP. Material and methods: Ninety patients of aged between 50 to 70 years of ASA-PS I, II scheduled for TURP were randomly allocated into 2 groups of 45 in each group. Group A patients were received spinal (2 ml of hyperbaric bupivacaine and Group B were received saddle block (2 ml of hyperbaric bupivacaine. Baseline systolic, diastolic and mean arterial pressure, heart rate, oxygen saturation were recorded and measured subsequently. The height of block was noted in both groups. Hypotension was corrected by administration of phenylephrine 50 mcg bolus and total requirement of vasopressor was noted. Complications (volume overload, TURP syndrome etc. were noted. Results: Incidence of hypotension and vasopressor requirement was less (P < 0.01 in Gr B patients.Adequate surgical condition was achieved in both groups. There was no incidence of volume overload, TURP syndrome, and bladder perforation. Conclusion: TURP can be safely performed under saddle block without hypotension and less vasopressor requirement.

  15. The quantum Hall effect helicity

    Energy Technology Data Exchange (ETDEWEB)

    Shrivastava, Keshav N., E-mail: keshav1001@yahoo.com [Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia); School of Physics, University of Hyderabad, Hyderabad 500046 (India)

    2015-04-16

    The quantum Hall effect in semiconductor heterostructures is explained by two signs in the angular momentum j=l±s and g=(2j+1)/(2l+1) along with the Landau factor (n+1/2). These modifications in the existing theories explain all of the fractional charges. The helicity which is the sign of the product of the linear momentum with the spin p.s plays an important role for the understanding of the data at high magnetic fields. In particular it is found that particles with positive sign in the spin move in one direction and those with negative sign move in another direction which explains the up and down stream motion of the particles.

  16. Stuart Hall: An Organic Intellectual

    Directory of Open Access Journals (Sweden)

    Johanna Fernández Castro

    2017-01-01

    Full Text Available Stuart Hall (3 February 1932 – 10 February 2014 is acknowledged as one of the founding figures of British Cultural Studies. His extensive academic work on topics such as race, ethnicity and identity reflects his own position as a diasporic intellectual. His contribution to the study of popular culture is determined by the importance of his political character in every social act, his non-deterministic view of Marxism, and is especially determined by his insistence on playing an active role beyond academia in order to contribute to the transformation of hegemonic structures. The following biography aims to give a focused view of his personal history and its direct influence on his key theoretical reflections.

  17. Assessment on problems associated with artificial insemination ...

    African Journals Online (AJOL)

    cedures, and poor management of AI bulls associated with poor motivations and skills of ..... edition. Mississippi State University. Pearson, Prentice Hall. Upper Saddle River, ... In: proceedings of the 13th annual conference of the Ethio-.

  18. Fertility Status of Fadama Soils in Gantsare Village, Wamakko Local ...

    African Journals Online (AJOL)

    acer

    1Department of Soil Science and Agricultural Engineering, 2Department of Agricultural Economics and Extension ..... with the findings of Arnold (1998). .... 12th ed. Prntice - Hall. Inc. Simon and. Scuster A.Viacon company Upper Saddle. River ...

  19. Time History Analysis of a Steel Water Tank with Pinned and Fixed ...

    African Journals Online (AJOL)

    Akorede

    It possesses numerous code of practice; and v. It has been .... Prentice Hall, Pearson Education Inc, Upper Saddle River,. New Jersey, U.S.A ... International Journal of Civil Engineering and Technology, 5 ... avert devastating impacts - Experts.

  20. The fractional quantum Hall effect

    International Nuclear Information System (INIS)

    Stormer, H.L.

    1988-01-01

    The fractional quantum Hall effect (FQHE), is the manifestation of a new, highly correlated, many-particle ground state that forms in a two-dimensional electron system at low temperatures and in high magnetic fields. It is an example of the new physics that has grown out of the tremendous recent advances in semiconductor material science, which has provided us with high-quality, lower-dimensional carrier systems. The novel electronic state exposes itself in transport experiments through quantization of the Hall resistance to an exact rational fraction of h/e, and concomitantly vanishing longitudinal resistivity. Its relevant energy scale is only a few degrees kelvin. The quantization is a consequence of the spontaneous formation of an energy gap separating the condensed ground state from its rather elusive quasiparticle excitations. The theoretical understanding of the novel quantum liquids which underlie the FQHE has predominantly emerged from an ingenious many-particle wave function strongly supported by numerous few-particle simulations. Theory has now constructed a complex model for ideal two-dimensional electron systems in the presence of high magnetic fields and makes definitive, often fascinating predictions. Experiments have successively uncovered odd-denominator fractional states reaching presently to 7/13. The application of new experimental tools to the FQHE, such as optics, microwaves, and phonon techniques promises the direct observation of such parameters as the gap energy and possibly even some of the more elusive quantities in the future. While theory and experiment in the FQHE appear to be converging, there remains considerable room for challenging surprises. This paper provides a concise overview of the FQHE. It focuses on the experimental aspects and states, but does not expand on the theoretical advances. 70 refs., 11 figs

  1. The quantum Hall effects: Philosophical approach

    Science.gov (United States)

    Lederer, P.

    2015-05-01

    The Quantum Hall Effects offer a rich variety of theoretical and experimental advances. They provide interesting insights on such topics as gauge invariance, strong interactions in Condensed Matter physics, emergence of new paradigms. This paper focuses on some related philosophical questions. Various brands of positivism or agnosticism are confronted with the physics of the Quantum Hall Effects. Hacking's views on Scientific Realism, Chalmers' on Non-Figurative Realism are discussed. It is argued that the difficulties with those versions of realism may be resolved within a dialectical materialist approach. The latter is argued to provide a rational approach to the phenomena, theory and ontology of the Quantum Hall Effects.

  2. Quantized Hall conductance as a topological invariant

    International Nuclear Information System (INIS)

    Niu, Q.; Thouless, Ds.J.; Wu, Y.S.

    1984-10-01

    Whenever the Fermi level lies in a gap (or mobility gap) the bulk Hall conductance can be expressed in a topologically invariant form showing the quantization explicitly. The new formulation generalizes the earlier result by TKNN to the situation where many body interaction and substrate disorder are also present. When applying to the fractional quantized Hall effect we draw the conclusion that there must be a symmetry breaking in the many body ground state. The possibility of writing the fractionally quantized Hall conductance as a topological invariant is also carefully discussed. 19 references

  3. Piezo Voltage Controlled Planar Hall Effect Devices.

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-22

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  4. Contribution of the study of the Hall Effect. Hall Effect of powder products

    International Nuclear Information System (INIS)

    Cherville, Jean

    1961-01-01

    This research thesis reports the development of an apparatus aimed at measuring the Hall Effect and the magneto-resistance of powders at room temperature and at the liquid nitrogen temperature. The author also proposes a theoretical contribution to the Hall Effect and reports the calculation of conditions to be met to obtain a correct value for the Hall constant. Results are experimentally verified. The method is then applied to the study of a set of powdered pre-graphitic graphites. The author shows that their Hall coefficient confirms the model already proposed by Mrozowski. The study of the Hall Effect of any kind of powders can thus be performed, and the Hall Effect can therefore be a mean to study mineral and organic compounds, and notably powdered biological molecules [fr

  5. The infrared Hall effect in YBCO: Temperature and frequency dependence of Hall scattering

    International Nuclear Information System (INIS)

    Grayson, M.; Cerne, J.; Drew, H.D.; Schmadel, D.C.; Hughes, R.; Preston, J.S.; Kung, P.J.; Vale, L.

    1999-01-01

    The authors measure the Hall angle, θ H , in YBCO films in the far- and mid-infrared to determine the temperature and frequency dependence of the Hall scattering. Using novel modulation techniques they measure both the Faraday rotation and ellipticity induced by these films in high magnetic fields to deduce the complex conductivity tensor. They observe a strong temperature dependence of the mid-infrared Hall conductivity in sharp contrast to the weak dependence of the longitudinal conductivity. By fitting the frequency dependent normal state Hall angle to a Lorentzian θ H (ω) = ω H /(γ H minus iω) they find the Hall frequency, ω H , is nearly independent of temperature. The Hall scattering rate, γ H , is consistent with γ H ∼ T 2 up to 200 K and is remarkably independent of IR frequency suggesting non-Fermi liquid behavior

  6. Topologically induced fractional Hall steps in the integer quantum Hall regime of MoS 2

    Science.gov (United States)

    Firoz Islam, SK; Benjamin, Colin

    2016-09-01

    The quantum magnetotransport properties of a monolayer of molybdenum disulfide are derived using linear response theory. In particular, the effect of topological terms on longitudinal and Hall conductivity is analyzed. The Hall conductivity exhibits fractional steps in the integer quantum Hall regime. Further complete spin and valley polarization of the longitudinal conductivitity is seen in presence of these topological terms. Finally, the Shubnikov-de Hass oscillations are suppressed or enhanced contingent on the sign of these topological terms.

  7. Spin Hall effect by surface roughness

    KAUST Repository

    Zhou, Lingjun; Grigoryan, Vahram L.; Maekawa, Sadamichi; Wang, Xuhui; Xiao, Jiang

    2015-01-01

    induced by surface roughness subscribes only to the side-jump contribution but not the skew scattering. The paradigm proposed in this paper provides the second, not if only, alternative to generate a sizable spin Hall effect.

  8. Mesoscopic effects in the quantum Hall regime

    Indian Academy of Sciences (India)

    . When band mixing between multiple Landau levels is present, mesoscopic effects cause a crossover from a sequence of quantum Hall transitions for weak disorder to classical behavior for strong disorder. This behavior may be of relevance ...

  9. Plasmon Geometric Phase and Plasmon Hall Shift

    Science.gov (United States)

    Shi, Li-kun; Song, Justin C. W.

    2018-04-01

    The collective plasmonic modes of a metal comprise a simple pattern of oscillating charge density that yields enhanced light-matter interaction. Here we unveil that beneath this familiar facade plasmons possess a hidden internal structure that fundamentally alters its dynamics. In particular, we find that metals with nonzero Hall conductivity host plasmons with an intricate current density configuration that sharply departs from that of ordinary zero Hall conductivity metals. This nontrivial internal structure dramatically enriches the dynamics of plasmon propagation, enabling plasmon wave packets to acquire geometric phases as they scatter. At boundaries, these phases accumulate allowing plasmon waves that reflect off to experience a nonreciprocal parallel shift. This plasmon Hall shift, tunable by Hall conductivity as well as plasmon wavelength, displaces the incident and reflected plasmon trajectories and can be readily probed by near-field photonics techniques. Anomalous plasmon geometric phases dramatically enrich the nanophotonics toolbox, and yield radical new means for directing plasmonic beams.

  10. A system for pulse Hall effect measurements

    International Nuclear Information System (INIS)

    Orzechowski, T.; Kupczak, R.

    1975-01-01

    Measuring system for fast Hall-voltage changes in an n-type germanium sample irradiated at liquid nitrogen temperature with a high-energy electron-beam from the Van de Graaff accelerator is described. (author)

  11. Novel optical probe for quantum Hall system

    Indian Academy of Sciences (India)

    to explore Landau levels of a two-dimensional electron gas (2DEG) in modulation doped ... Keywords. Surface photovoltage spectroscopy; quantum Hall effect; Landau levels; edge states. ... An optical fibre carries light from tunable diode laser.

  12. AA under construction in its hall

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    The Antiproton Accumulator was installed in a specially built hall. Here we see it at an "early" stage of installation, just a few magnets on the floor, no vacuum chamber at all, but: 3 months later there was circulating beam !

  13. Elementary theory of quantum Hall effect

    Directory of Open Access Journals (Sweden)

    Keshav N. Shrivastava

    2008-04-01

    Full Text Available The Hall effect is the generation of a current perpendicular to both the direction of the applied electric as well as magnetic field in a metal or in a semiconductor. It is used to determine the concentration of electrons. The quantum Hall effect with integer quantization was discovered by von Klitzing and fractionally charged states were found by Tsui, Stormer and Gossard. Robert Laughlin explained the quantization of Hall current by using “flux quantization” and introduced incompressibility to obtain the fractional charge. We have developed the theory of the quantum Hall effect by using the theory of angular momentum. Our predicted fractions are in accord with those measured. We emphasize our explanation of the observed phenomena. We use spin to explain the fractional charge and hence we discover spin-charge locking.

  14. The fluctuation Hall conductivity and the Hall angle in type-II superconductor under magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Tinh, Bui Duc, E-mail: tinhbd@hnue.edu.vn [Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam); Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam); Hoc, Nguyen Quang; Thu, Le Minh [Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam)

    2016-02-15

    Highlights: • The time-dependent Ginzburg–Landau was used to calculate fluctuation Hall conductivity and Hall angle in type-II superconductor in 2D and 3D. • We obtain analytical expressions for the fluctuation Hall conductivity and the Hall angle summing all Landau levels without need to cutoff higher Landau levels to treat arbitrary magnetic field. • The results were compared to the experimental data on YBCO. - Abstract: The fluctuation Hall conductivity and the Hall angle, describing the Hall effect, are calculated for arbitrary value of the imaginary part of the relaxation time in the frame of the time-dependent Ginzburg–Landau theory in type II-superconductor with thermal noise describing strong thermal fluctuations. The self-consistent Gaussian approximation is used to treat the nonlinear interaction term in dynamics. We obtain analytical expressions for the fluctuation Hall conductivity and the Hall angle summing all Landau levels without need to cutoff higher Landau levels to treat arbitrary magnetic field. The results are compared with experimental data on high-T{sub c} superconductor.

  15. Modeling and Experiments on Ballistic Impact into UHMWPE Yarns Using Flat and Saddle-Nosed Projectiles

    Directory of Open Access Journals (Sweden)

    Stuart Leigh Phoenix

    2017-03-01

    Full Text Available Yarn shooting experiments were conducted to determine the ballistically-relevant, Young’s modulus and tensile strength of ultra-high molecular weight polyethylene (UHMWPE fiber. Target specimens were Dyneema® SK76 yarns (1760 dtex, twisted to 40 turns/m, and initially tensioned to stresses ranging from 29 to 2200 MPa. Yarns were impacted, transversely, by two types of cylindrical steel projectiles at velocities ranging from 150 to 555 m/s: (i a reverse-fired, fragment simulating projectile (FSP where the flat rear face impacted the yarn rather than the beveled nose; and (ii a ‘saddle-nosed projectile’ having a specially contoured nose imparting circular curvature in the region of impact, but opposite curvature transversely to prevent yarn slippage off the nose. Experimental data consisted of sequential photographic images of the progress of the triangular transverse wave, as well as tensile wave speed measured using spaced, piezo-electric sensors. Yarn Young’s modulus, calculated from the tensile wave-speed, varied from 133 GPa at minimal initial tension to 208 GPa at the highest initial tensions. However, varying projectile impact velocity, and thus, the strain jump on impact, had negligible effect on the modulus. Contrary to predictions from the classical Cole-Smith model for 1D yarn impact, the critical velocity for yarn failure differed significantly for the two projectile types, being 18% lower for the flat-faced, reversed FSP projectile compared to the saddle-nosed projectile, which converts to an apparent 25% difference in yarn strength. To explain this difference, a wave-propagation model was developed that incorporates tension wave collision under blunt impact by a flat-faced projectile, in contrast to outward wave propagation in the classical model. Agreement between experiment and model predictions was outstanding across a wide range of initial yarn tensions. However, plots of calculated failure stress versus yarn pre

  16. NAS Decadal Review Town Hall

    Science.gov (United States)

    The National Academies of Sciences, Engineering and Medicine is seeking community input for a study on the future of materials research (MR). Frontiers of Materials Research: A Decadal Survey will look at defining the frontiers of materials research ranging from traditional materials science and engineering to condensed matter physics. Please join members of the study committee for a town hall to discuss future directions for materials research in the United States in the context of worldwide efforts. In particular, input on the following topics will be of great value: progress, achievements, and principal changes in the R&D landscape over the past decade; identification of key MR areas that have major scientific gaps or offer promising investment opportunities from 2020-2030; and the challenges that MR may face over the next decade and how those challenges might be addressed. This study was requested by the Department of Energy and the National Science Foundation. The National Academies will issue a report in 2018 that will offer guidance to federal agencies that support materials research, science policymakers, and researchers in materials research and other adjoining fields. Learn more about the study at http://nas.edu/materials.

  17. Resistive Instabilities in Hall Current Plasma Discharge

    International Nuclear Information System (INIS)

    Litvak, Andrei A.; Fisch, Nathaniel J.

    2000-01-01

    Plasma perturbations in the acceleration channel of a Hall thruster are found to be unstable in the presence of collisions. Both electrostatic lower-hybrid waves and electromagnetic Alfven waves transverse to the applied electric and magnetic field are found to be unstable due to collisions in the E X B electron flow. These results are obtained assuming a two-fluid hydrodynamic model in slab geometry. The characteristic frequencies of these modes are consistent with experimental observations in Hall current plasma thrusters

  18. Are tent halls subject to property tax?

    Directory of Open Access Journals (Sweden)

    Mariusz Macudziński

    2016-12-01

    Full Text Available The presented publication is a response to currently asked questions and interpretative doubts of taxpayers and tax authorities, namely whether tent halls are subject to property tax. General issues connected with an entity and a subject of taxation of this tax are presented herein. The answer to the question asked is then provided through the qualification of constructions works and the allocation of tent halls in the proper category of the works, with the use of the current law.

  19. Fractional statistics and fractional quantized Hall effect

    International Nuclear Information System (INIS)

    Tao, R.; Wu, Y.S.

    1985-01-01

    The authors suggest that the origin of the odd-denominator rule observed in the fractional quantized Hall effect (FQHE) may lie in fractional statistics which govern quasiparticles in FQHE. A theorem concerning statistics of clusters of quasiparticles implies that fractional statistics do not allow coexistence of a large number of quasiparticles at fillings with an even denominator. Thus, no Hall plateau can be formed at these fillings, regardless of the presence of an energy gap. 15 references

  20. Hall effect in organic layered conductors

    Directory of Open Access Journals (Sweden)

    R.A.Hasan

    2006-01-01

    Full Text Available The Hall effect in organic layered conductors with a multisheeted Fermi surfaces was considered. It is shown that the experimental study of Hall effect and magnetoresistance anisotropy at different orientations of current and a quantizing magnetic field relative to the layers makes it possible to determine the contribution of various charge carriers groups to the conductivity, and to find out the character of Fermi surface anisotropy in the plane of layers.

  1. Parameters of the center of pressure displacement on the saddle during hippotherapy on different surfaces

    Directory of Open Access Journals (Sweden)

    Fabiana M. Flores

    2015-06-01

    Full Text Available Background: Hippotherapy uses horseback riding movements for therapeutic purposes. In addition to the horse's movement, the choice of equipment and types of floor are also useful in the intervention. The quantification of dynamic parameters that define the interaction of the surface of contact between horse and rider provides insight into how the type of floor surface variations act upon the subject's postural control. Objective: To test whether different types of surfaces promote changes in the amplitude (ACOP and velocity (VCOP of the center of pressure (COP displacement during the rider's contact with the saddle on the horse's back. Method: Twenty two healthy adult male subjects with experience in riding were evaluated. The penetration resistances of asphalt, sand and grass surfaces were measured. The COP data were collected on the three surfaces using a pressure measurement mat. Results: ACOP values were higher in sand, followed by grass and asphalt, with significant differences between sand and asphalt (anteroposterior, p=0.042; mediolateral, p=0.019. The ACOP and VCOP values were higher in the anteroposterior than in the mediolateral direction on all surfaces (ACOP, p=0.001; VCOP, p=0.006. The VCOP did not differ between the surfaces. Conclusion: Postural control, measured by the COP displacement, undergoes variations in its amplitude as a result of the type of floor surface. Therefore, these results reinforce the importance of the choice of floor surface when defining the strategy to be used during hippotherapy intervention.

  2. Parameters of the center of pressure displacement on the saddle during hippotherapy on different surfaces.

    Science.gov (United States)

    Flores, Fabiana M; Dagnese, Frederico; Mota, Carlos B; Copetti, Fernando

    2015-01-01

    Hippotherapy uses horseback riding movements for therapeutic purposes. In addition to the horse's movement, the choice of equipment and types of floor are also useful in the intervention. The quantification of dynamic parameters that define the interaction of the surface of contact between horse and rider provides insight into how the type of floor surface variations act upon the subject's postural control. To test whether different types of surfaces promote changes in the amplitude (ACOP) and velocity (VCOP) of the center of pressure (COP) displacement during the rider's contact with the saddle on the horse's back. Twenty two healthy adult male subjects with experience in riding were evaluated. The penetration resistances of asphalt, sand and grass surfaces were measured. The COP data were collected on the three surfaces using a pressure measurement mat. ACOP values were higher in sand, followed by grass and asphalt, with significant differences between sand and asphalt (anteroposterior, p=0.042; mediolateral, p=0.019). The ACOP and VCOP values were higher in the anteroposterior than in the mediolateral direction on all surfaces (ACOP, p=0.001; VCOP, p=0.006). The VCOP did not differ between the surfaces. Postural control, measured by the COP displacement, undergoes variations in its amplitude as a result of the type of floor surface. Therefore, these results reinforce the importance of the choice of floor surface when defining the strategy to be used during hippotherapy intervention.

  3. A smooth landscape: ending saddle point inflation requires features to be shallow

    International Nuclear Information System (INIS)

    Battefeld, Diana; Battefeld, Thorsten

    2013-01-01

    We consider inflation driven near a saddle point in a higher dimensional field space, which is the most likely type of slow roll inflation on the string theoretical landscape; anthropic arguments need to be invoked in order to find a sufficiently flat region. To give all inflatons large masses after inflation and yield a small but positive cosmological constant, the trajectory in field space needs to terminate in a hole on the inflationary plateau, introducing a curved end-of-inflation hypersurface. We compute non-Gaussianities (bi- and tri-spectrum) caused by this curved hyper-surface and find a negative, potentially large, local non-linearity parameter. To be consistent with current observational bounds, the hole needs to be shallow, i.e. considerably wider than deep in natural units. To avoid singling out our vacuum as special (i.e. more special than a positive cosmological constant entails), we deduce that all features on field space should be similarly shallow, severely limiting the type of landscapes one may use for inflationary model building. We justify the use of a truncated Fourier series with random coefficients, which are suppressed the higher the frequency, to model such a smooth landscape by a random potential, as is often done in the literature without a good a priory reason

  4. Global analysis of dynamical decision-making models through local computation around the hidden saddle.

    Directory of Open Access Journals (Sweden)

    Laura Trotta

    Full Text Available Bistable dynamical switches are frequently encountered in mathematical modeling of biological systems because binary decisions are at the core of many cellular processes. Bistable switches present two stable steady-states, each of them corresponding to a distinct decision. In response to a transient signal, the system can flip back and forth between these two stable steady-states, switching between both decisions. Understanding which parameters and states affect this switch between stable states may shed light on the mechanisms underlying the decision-making process. Yet, answering such a question involves analyzing the global dynamical (i.e., transient behavior of a nonlinear, possibly high dimensional model. In this paper, we show how a local analysis at a particular equilibrium point of bistable systems is highly relevant to understand the global properties of the switching system. The local analysis is performed at the saddle point, an often disregarded equilibrium point of bistable models but which is shown to be a key ruler of the decision-making process. Results are illustrated on three previously published models of biological switches: two models of apoptosis, the programmed cell death and one model of long-term potentiation, a phenomenon underlying synaptic plasticity.

  5. Model reduction method using variable-separation for stochastic saddle point problems

    Science.gov (United States)

    Jiang, Lijian; Li, Qiuqi

    2018-02-01

    In this paper, we consider a variable-separation (VS) method to solve the stochastic saddle point (SSP) problems. The VS method is applied to obtain the solution in tensor product structure for stochastic partial differential equations (SPDEs) in a mixed formulation. The aim of such a technique is to construct a reduced basis approximation of the solution of the SSP problems. The VS method attempts to get a low rank separated representation of the solution for SSP in a systematic enrichment manner. No iteration is performed at each enrichment step. In order to satisfy the inf-sup condition in the mixed formulation, we enrich the separated terms for the primal system variable at each enrichment step. For the SSP problems by regularization or penalty, we propose a more efficient variable-separation (VS) method, i.e., the variable-separation by penalty method. This can avoid further enrichment of the separated terms in the original mixed formulation. The computation of the variable-separation method decomposes into offline phase and online phase. Sparse low rank tensor approximation method is used to significantly improve the online computation efficiency when the number of separated terms is large. For the applications of SSP problems, we present three numerical examples to illustrate the performance of the proposed methods.

  6. On the trajectories of CRL...LR...R orbits, their period-doubling cascades and saddle-node bifurcation cascades

    International Nuclear Information System (INIS)

    Cerrada, Lucia; San Martin, Jesus

    2011-01-01

    In this Letter, it is shown that from a two region partition of the phase space of a one-dimensional dynamical system, a p-region partition can be obtained for the CRL...LR...R orbits. That is, permutations associated with symbolic sequences are obtained. As a consequence, the trajectory in phase space is directly deduced from permutation. From this permutation other permutations associated with period-doubling and saddle-node bifurcation cascades are derived, as well as other composite permutations. - Research highlights: → Symbolic sequences are the usual topological approach to dynamical systems. → Permutations bear more physical information than symbolic sequences. → Period-doubling cascade permutations associated with original sequences are obtained. → Saddle-node cascade permutations associated with original sequences are obtained. → Composite permutations are derived.

  7. Non-invasive Investigation and Management of Aortic Saddle Embolus in a 7-Month-Old Infant

    International Nuclear Information System (INIS)

    O'Connell, Martin J.; Duff, Desmond F.; Hayes, Roisin M.

    2002-01-01

    There are few reports in the literature on the ultrasound appearance of aortic saddle embolus, and none relating to small children. This unusual condition is usually diagnosed angiographically. The purpose of this report is to show how effectively high-frequency ultrasound can identify a saddle embolus with its associated collateral circulation in a young child, and to demonstrate its usefulness in monitoring the efficacy of treatment. In this case the embolus occurred as a complication of parvovirus B19 myocarditis and was diagnosed and followed up entirely by ultrasound examination,with no invasive procedure performed. The early development of an extensive collateral circulation prevented distal tissue necrosis and allowed a conservative approach to management

  8. A computational/directional solidification method to establish saddle points on the Mg-Al-Ca liquidus

    International Nuclear Information System (INIS)

    Cao Hongbo; Zhang Chuan; Zhu Jun; Cao Guoping; Kou Sindo; Schmid-Fetzer, Rainer; Chang, Y. Austin

    2008-01-01

    We established two saddle point maxima, L + α(Mg) + C14 and L + α(Mg) + C36, on the monovariant liquidus, calculated from a previously presented thermodynamic description, by characterizing the microstructures of several directionally solidified alloys in the near-solidification front zone, the mushy zone, and the steady-state zone using optical microscopy, scanning electron microscopy and transmission electron microscopy

  9. Quasar Microlensing at High Magnification and the Role of Dark Matter: Enhanced Fluctuations and Suppressed Saddle Points

    Science.gov (United States)

    Schechter, Paul L.; Wambsganss, Joachim

    2002-12-01

    Contrary to naive expectation, diluting the stellar component of the lensing galaxy in a highly magnified system with smoothly distributed ``dark'' matter increases rather than decreases the microlensing fluctuations caused by the remaining stars. For a bright pair of images straddling a critical curve, the saddle point (of the arrival time surface) is much more strongly affected than the associated minimum. With a mass ratio of smooth matter to microlensing matter of 4:1, a saddle point with a macromagnification of μ=9.5 will spend half of its time more than a magnitude fainter than predicted. The anomalous flux ratio observed for the close pair of images in MG 0414+0534 is a factor of 5 more likely than computed by Witt, Mao, & Schechter, if the smooth matter fraction is as high as 93%. The magnification probability histograms for macroimages exhibit a distinctly different structure that varies with the smooth matter content, providing a handle on the smooth matter fraction. Enhanced fluctuations can manifest themselves either in the temporal variations of a light curve or as flux ratio anomalies in a single epoch snapshot of a multiply imaged system. While the millilensing simulations of Metcalf & Madau also give larger anomalies for saddle points than for minima, the effect appears to be less dramatic for extended subhalos than for point masses. Moreover, microlensing is distinguishable from millilensing because it will produce noticeable changes in the magnification on a timescale of a decade or less.

  10. Novel spin transition between S = 5/2 and S = 3/2 in highly saddled iron(III) porphyrin complexes at extremely low temperatures.

    Science.gov (United States)

    Ohgo, Yoshiki; Chiba, Yuya; Hashizume, Daisuke; Uekusa, Hidehiro; Ozeki, Tomoji; Nakamura, Mikio

    2006-05-14

    A novel spin transition between S = 5/2 and S = 3/2 has been observed for the first time in five-coordinate, highly saddled iron(III) porphyrinates by EPR and SQUID measurements at extremely low temperatures.

  11. 75 FR 22770 - Gary E. Hall and Rita Hall; Notice of Availability of Environmental Assessment

    Science.gov (United States)

    2010-04-30

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13652-000-Montana] Gary E. Hall and Rita Hall; Notice of Availability of Environmental Assessment April 22, 2010. In accordance with the National Environmental Policy Act of 1969, as amended, and the Federal Energy Regulatory...

  12. The effect of hand hygiene on illness rate among students in university residence halls.

    Science.gov (United States)

    White, Cindy; Kolble, Robin; Carlson, Rebecca; Lipson, Natasha; Dolan, Mike; Ali, Yusuf; Cline, Mojee

    2003-10-01

    Several studies have indicated a connection between hand sanitization and infection control in numerous settings such as extended care facilities, schools, and hospitals. The purpose of this study was to assess the effectiveness of both a hand-hygiene message campaign and the use of an alcohol gel hand sanitizer in decreasing the incidence of upper-respiratory illness among students living in university residence halls. This study involved a total of 430 students recruited from 4 residence halls during the fall semester at the University of Colorado at the Boulder campus. Dormitories were paired into control and product groups. In the product groups, alcohol gel hand-sanitizer dispensers were installed in every room, bathroom, and dining hall. The data were statistically analyzed for the differences between product and control groups in reported symptoms, illness rates, and absenteeism from classes. The overall increase in hand-hygiene behavior and reduction in symptoms, illness rates, and absenteeism between the product group and control group was statistically significant. Reductions in upper respiratory-illness symptoms ranged from 14.8% to 39.9%. Total improvement in illness rate was 20%. The product group had 43% less missed school/work days. Hand-hygiene practices were improved with increased frequency of handwashing through increasing awareness of the importance of hand hygiene, and the use of alcohol gel hand sanitizer in university dormitories. This resulted in fewer upper respiratory-illness symptoms, lower illness rates, and lower absenteeism.

  13. Charge carrier coherence and Hall effect in organic semiconductors

    Science.gov (United States)

    Yi, H. T.; Gartstein, Y. N.; Podzorov, V.

    2016-01-01

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor. PMID:27025354

  14. Charge carrier coherence and Hall effect in organic semiconductors.

    Science.gov (United States)

    Yi, H T; Gartstein, Y N; Podzorov, V

    2016-03-30

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor.

  15. Dr. Hall and the work cure.

    Science.gov (United States)

    Reed, Kathlyn L

    2005-01-01

    Herbert James Hall, MD (1870-1923), was a pioneer in the systematic and organized study of occupation as therapy for persons with nervous and mental disorders that he called the "work cure." He began his work in 1904 during the early years of the Arts and Crafts Movement in the United States. His primary interest was the disorder neurasthenia, a condition with many symptoms including chronic fatigue, stress, and inability to work or perform everyday tasks. The prevailing treatment of the day was absolute bed rest known as the "rest cure." Hall believed that neurasthenia was not caused by overwork but by faulty living habits that could be corrected through an ordered life schedule and selected occupations. He identified several principles of therapy that are still used today including graded activity and energy conservation. Dr. Adolph Meyer credits Hall for organizing the ideas on the therapeutic use of occupation (Meyer, 1922). Hall also provided the name American Occupational Therapy Association for the professional organization and served as the fourth president. For his many contributions to the profession Hall deserves to be recognized as a major contributor to the development and organization of occupational therapy.

  16. A new CMOS Hall angular position sensor

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, R.S.; Drljaca, P. [Swiss Federal Inst. of Tech., Lausanne (Switzerland); Schott, C.; Racz, R. [SENTRON AG, Zug (Switzerland)

    2001-06-01

    The new angular position sensor consists of a combination of a permanent magnet attached to a shaft and of a two-axis magnetic sensor. The permanent magnet produces a magnetic field parallel with the magnetic sensor plane. As the shaft rotates, the magnetic field also rotates. The magnetic sensor is an integrated combination of a CMOS Hall integrated circuit and a thin ferromagnetic disk. The CMOS part of the system contains two or more conventional Hall devices positioned under the periphery of the disk. The ferromagnetic disk converts locally a magnetic field parallel with the chip surface into a field perpendicular to the chip surface. Therefore, a conventional Hall element can detect an external magnetic field parallel with the chip surface. As the direction of the external magnetic field rotates in the chip plane, the output voltage of the Hall element varies as the cosine of the rotation angle. By placing the Hall elements at the appropriate places under the disk periphery, we may obtain the cosine signals shifted by 90 , 120 , or by any other angle. (orig.)

  17. Composite fermions in the quantum Hall effect

    International Nuclear Information System (INIS)

    Johnson, B.L.; Kirczenow, G.

    1997-01-01

    The quantum Hall effect and associated quantum transport phenomena in low-dimensional systems have been the focus of much attention for more than a decade. Recent theoretical development of interesting quasiparticles - 'composite fermions' - has led to significant advances in understanding and predicting the behaviour of two-dimensional electron systems under high transverse magnetic fields. Composite fermions may be viewed as fermions carrying attached (fictitious) magnetic flux. Here we review models of the integer and fractional quantum Hall effects, including the development of a unified picture of the integer and fractional effects based upon composite fermions. The composite fermion picture predicts remarkable new physics: the formation of a Fermi surface at high magnetic fields, and anomalous ballistic transport, thermopower, and surface acoustic wave behaviour. The specific theoretical predictions of the model, as well as the body of experimental evidence for these phenomena are reviewed. We also review recent edge-state models for magnetotransport in low-dimensional devices based on the composite fermion picture. These models explain the fractional quantum Hall effect and transport phenomena in nanoscale devices in a unified framework that also includes edge state models of the integer quantum Hall effect. The features of the composite fermion edge-state model are compared and contrasted with those of other recent edge-state models of the fractional quantum Hall effect. (author)

  18. Air temperature gradient in large industrial hall

    Science.gov (United States)

    Karpuk, Michał; Pełech, Aleksander; Przydróżny, Edward; Walaszczyk, Juliusz; Szczęśniak, Sylwia

    2017-11-01

    In the rooms with dominant sensible heat load, volume airflow depends on many factors incl. pre-established temperature difference between exhaust and supply airflow. As the temperature difference is getting higher, airflow volume drops down, consequently, the cost of AHU is reduced. In high industrial halls with air exhaust grids located under the ceiling additional temperature gradient above working zone should be taken into consideration. In this regard, experimental research of the vertical air temperature gradient in high industrial halls were carried out for the case of mixing ventilation system The paper presents the results of air temperature distribution measurements in high technological hall (mechanically ventilated) under significant sensible heat load conditions. The supply airflow was delivered to the hall with the help of the swirl diffusers while exhaust grids were located under the hall ceiling. Basing on the air temperature distribution measurements performed on the seven pre-established levels, air temperature gradient in the area between 2.0 and 7.0 m above the floor was calculated and analysed.

  19. Field theory approach to quantum hall effect

    International Nuclear Information System (INIS)

    Cabo, A.; Chaichian, M.

    1990-07-01

    The Fradkin's formulation of statistical field theory is applied to the Coulomb interacting electron gas in a magnetic field. The electrons are confined to a plane in normal 3D-space and also interact with the physical 3D-electromagnetic field. The magnetic translation group (MTG) Ward identities are derived. Using them it is shown that the exact electron propagator is diagonalized in the basis of the wave functions of the free electron in a magnetic field whenever the MTG is unbroken. The general tensor structure of the polarization operator is obtained and used to show that the Chern-Simons action always describes the Hall effect properties of the system. A general proof of the Streda formula for the Hall conductivity is presented. It follows that the coefficient of the Chern-Simons terms in the long-wavelength approximation is exactly given by this relation. Such a formula, expressing the Hall conductivity as a simple derivative, in combination with diagonal form of the full propagator allows to obtain a simple expressions for the filling factor and the Hall conductivity. Indeed, these results, after assuming that the chemical potential lies in a gap of the density of states, lead to the conclusion that the Hall conductivity is given without corrections by σ xy = νe 2 /h where ν is the filling factor. In addition it follows that the filling factor is independent of the magnetic field if the chemical potential remains in the gap. (author). 21 ref, 1 fig

  20. Extrinsic spin Hall effect in graphene

    Science.gov (United States)

    Rappoport, Tatiana

    The intrinsic spin-orbit coupling in graphene is extremely weak, making it a promising spin conductor for spintronic devices. In addition, many applications also require the generation of spin currents in graphene. Theoretical predictions and recent experimental results suggest one can engineer the spin Hall effect in graphene by greatly enhancing the spin-orbit coupling in the vicinity of an impurity. The extrinsic spin Hall effect then results from the spin-dependent skew scattering of electrons by impurities in the presence of spin-orbit interaction. This effect can be used to efficiently convert charge currents into spin-polarized currents. I will discuss recent experimental results on spin Hall effect in graphene decorated with adatoms and metallic cluster and show that a large spin Hall effect can appear due to skew scattering. While this spin-orbit coupling is small if compared with what it is found in metals, the effect is strongly enhanced in the presence of resonant scattering, giving rise to robust spin Hall angles. I will present our single impurity scattering calculations done with exact partial-wave expansions and complement the analysis with numerical results from a novel real-space implementation of the Kubo formalism for tight-binding Hamiltonians. The author acknowledges the Brazilian agencies CNPq, CAPES, FAPERJ and INCT de Nanoestruturas de Carbono for financial support.

  1. Fifty per cent reduction in solution gas flaring : a report to the Saddle Hills Awareness Committee

    International Nuclear Information System (INIS)

    1999-01-01

    Information by the Alberta Energy Company to the Saddle Hills Awareness Committee (SHAC) regarding company operations in the West Peace River Arch of the western Canadian Sedimentary Basin in northwest Alberta is presented, the purpose being to bring the Committee up-to-date, and respond to concerns about the health effects of sour gas emissions. The SHAC represents citizens who are concerned about issues relating to sour gas emissions. AEC West, a business unit of Alberta Energy Company, operates two sour gas processing plants, one sweet gas plant and three sour oil batteries in the Grande Prairie area. AEC's gas plants are connected by pipelines and process petroleum and natural gas products from approximately 200 oil and gas wells. The H 2 S content of the natural gas being processed by AEC's various plants ranges from trace amounts to 11 per cent. Activities at AEC's Hythe plant and at the Sexsmith plant, and the company's gas storage project are briefly reviewed. An analysis is included of the role that flaring plays in the petroleum and natural gas industry, emphasizing AEC West's efforts during 1997 to reduce solution gas flaring volumes from single well oil batteries by 50 per cent. Other AEC West environmental protection initiatives include the preliminary regional airshed study sponsored by the company which resulted in part from SHAC feedback and in part from the innovative approach of AEC employees. AEC West established the industry's first Ombudsman to provide a problem resolution focus on landowner complaints and introduced a policy of making available solution gas that would eventually be flared to industrial colleagues, free of charge

  2. Localization in a quantum spin Hall system.

    Science.gov (United States)

    Onoda, Masaru; Avishai, Yshai; Nagaosa, Naoto

    2007-02-16

    The localization problem of electronic states in a two-dimensional quantum spin Hall system (that is, a symplectic ensemble with topological term) is studied by the transfer matrix method. The phase diagram in the plane of energy and disorder strength is exposed, and demonstrates "levitation" and "pair annihilation" of the domains of extended states analogous to that of the integer quantum Hall system. The critical exponent nu for the divergence of the localization length is estimated as nu congruent with 1.6, which is distinct from both exponents pertaining to the conventional symplectic and the unitary quantum Hall systems. Our analysis strongly suggests a different universality class related to the topology of the pertinent system.

  3. Hall probe magnetometer for SSC magnet cables

    International Nuclear Information System (INIS)

    Cross, R.W.; Goldfarb, R.B.

    1991-01-01

    The authors of this paper constructed a Hall probe magnetometer to measure the magnetization hysteresis loops of Superconducting Super Collider magnet cables. The instrument uses two Hall-effect field sensors to measure the applied field H and the magnetic induction B. Magnetization M is calculated from the difference of the two quantities. The Hall probes are centered coaxially in the bore of a superconducting solenoid with the B probe against the sample's broad surface. An alternative probe arrangement, in which M is measured directly, aligns the sample probe parallel to the field. The authors measured M as a function of H and field cycle rate both with and without a dc transport current. Flux creep as a function of current was measured from the dependence of ac loss on the cycling rate and from the decay of magnetization with time. Transport currents up to 20% of the critical current have minimal effect on magnetization and flux creep

  4. Spin Hall Effect in Doped Semiconductor Structures

    Science.gov (United States)

    Tse, Wang-Kong; Das Sarma, Sankar

    2006-03-01

    We present a microscopic theory of the extrinsic spin Hall effect based on the diagrammatic perturbation theory. Side-jump (SJ) and skew-scattering (SS) contributions are explicitly taken into account to calculate the spin Hall conductivity, and we show their effects scale as σxy^SJ/σxy^SS ˜(/τ)/ɛF, where τ being the transport relaxation time. Motivated by recent experimental work we apply our theory to n-doped and p-doped 3D and 2D GaAs structures, obtaining analytical formulas for the SJ and SS contributions. Moreover, the ratio of the spin Hall conductivity to longitudinal conductivity is found as σs/σc˜10-3-10-4, in reasonable agreement with the recent experimental results of Kato et al. [Science 306, 1910 (2004)] in n-doped 3D GaAs system.

  5. Shielding consideration for the SSCL experimental halls

    International Nuclear Information System (INIS)

    Bull, J.; Coyne, J.; Mokhov, N.; Stapleton, G.

    1994-03-01

    The Superconducting Super Collider which is being designed and built in Waxahachie, Texas consists Of series of proton accelerators, culminating in a 20 Te proton on proton collider. The collider will be in a tunnel which will be 87 km in circumference and. on average about 30 meters underground. The present design calls for two large interaction halls on the east side of the ring. The shielding for these halls is being designed for an interaction rate of 10 9 Hz or 10 16 interactions per year, based on 10 7 seconds per operational year. SSC guidelines require that the shielding be designed to meet the criterion of 1mSv per year for open areas off site 2mSv per year for open areas on site, and 2mSv per year for controlled areas. Only radiation workers will be routinely allowed to work in controlled areas. It should be pointed that there is a potential for an accidental full beam loss in either of the experimental halls, and this event would consist of the loss of the full circulating beam up to 4 x 10 14 protons. With the present design. the calculated dose equivalent for this event is about 10% of the annual dose equivalent for the normal p-p interactions, so that die accident condition does not control the shielding. If, for instance, local shielding within the experimental hall is introduced into the calculations, this could change. The shielding requirements presented here are controlled by the normal p-p interactions. Three important questions were addressed in the present calculations. They are (1) the thickness of the roof over the experimental halls, (2) the configuration of the shafts and adits which give access to the halls, and (3) the problem of ground water and air activation

  6. Developments in Scanning Hall Probe Microscopy

    Science.gov (United States)

    Chouinard, Taras; Chu, Ricky; David, Nigel; Broun, David

    2009-05-01

    Low temperature scanning Hall probe microscopy is a sensitive means of imaging magnetic structures with high spatial resolution and magnetic flux sensitivity approaching that of a Superconducting Quantum Interference Device. We have developed a scanning Hall probe microscope with novel features, including highly reliable coarse positioning, in situ optimization of sensor-sample alignment and capacitive transducers for linear, long range positioning measurement. This has been motivated by the need to reposition accurately above fabricated nanostructures such as small superconducting rings. Details of the design and performance will be presented as well as recent progress towards time-resolved measurements with sub nanosecond resolution.

  7. Enhanced Performance of Cylindrical Hall Thrusters

    International Nuclear Information System (INIS)

    Raitses, Y.; Smirnov, A.; Fisch, N.J.

    2007-01-01

    The cylindrical thruster differs significantly in its underlying physical mechanisms from the conventional annular Hall thruster. It features high ionization efficiency, quiet operation, ion acceleration in a large volume-to-surface ratio channel, and performance comparable with the state-of-the-art conventional Hall thrusters. Very significant plume narrowing, accompanied by the increase of the energetic ion fraction and improvement of ion focusing, led to 50-60% increase of the thruster anode efficiency. These improvements were achieved by overrunning the discharge current in the magnetized thruster plasma

  8. Inverse spin Hall effect by spin injection

    Science.gov (United States)

    Liu, S. Y.; Horing, Norman J. M.; Lei, X. L.

    2007-09-01

    Motivated by a recent experiment [S. O. Valenzuela and M. Tinkham, Nature (London) 442, 176 (2006)], the authors present a quantitative microscopic theory to investigate the inverse spin-Hall effect with spin injection into aluminum considering both intrinsic and extrinsic spin-orbit couplings using the orthogonalized-plane-wave method. Their theoretical results are in good agreement with the experimental data. It is also clear that the magnitude of the anomalous Hall resistivity is mainly due to contributions from extrinsic skew scattering.

  9. Prototype dining hall energy efficiency study

    Energy Technology Data Exchange (ETDEWEB)

    Mazzucchi, R.P.; Bailey, S.A.; Zimmerman, P.W.

    1988-06-01

    The energy consumption of food service facilities is among the highest of any commercial building type, owing to the special requirements for food preparation, sanitation, and ventilation. Consequently, the US Air Force Engineering and Services Center (AFESC) contracted with Pacific Northwest Laboratory (PNL) to collect and analyze end-use energy consumption data for a prototypical dining hall and make specific recommendations on cost-effective energy conservation options. This information will be used to establish or update criteria for dining hall designs and retrofits as appropriate. 6 refs., 21 figs., 23 tabs.

  10. Acoustics in rock and pop music halls

    DEFF Research Database (Denmark)

    Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2007-01-01

    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of rhythmic music, including rock and pop. Objective measurements were made of the acoustics of twenty rock music venues...... in Denmark and a questionnaire was used in a subjective assessment of those venues with professional rock musicians and sound engineers. Correlations between the objective and subjective results lead, among others, to a recommendation for reverberation time as a function of hall volume. Since the bass...

  11. Proton knock-out in Hall A

    International Nuclear Information System (INIS)

    Jager, K. de

    2003-01-01

    Proton knock-out is studied in a broad program in Hall A at Jefferson Lab. The first experiment performed in Hall A studied the 16 O(e,e'p) reaction. Since then proton knock-out experiments have studied a variety of aspects of that reaction, from single-nucleon properties to its mechanism, such as final-state interactions and two-body currents, in nuclei from 2 H to 16 O. In this review the accomplishments of this program will be summarized and an outlook given of expected future results. (orig.)

  12. Theory of fractional quantum Hall effect

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.

    1984-09-01

    A theory of the fractional quantum Hall effect is constructed by introducing 3-particle interactions breaking the symmetry for ν=1/3 according to a degeneracy theorem proved here. An order parameter is introduced and a gap in the single particle spectrum is found. The critical temperature, critical filling number and critical behaviour are determined as well as the Ginzburg-Landau equation coefficients. A first principle calculation of the Hall current is given. 3, 5, 7 electron tunneling and Josephson interference effects are predicted. (author)

  13. Bound values for Hall conductivity of heterogeneous medium under ...

    Indian Academy of Sciences (India)

    - ditions in inhomogeneous medium has been studied. It is shown that bound values for. Hall conductivity differ from bound values for metallic conductivity. This is due to the unusual character of current percolation under quantum Hall effect ...

  14. A Small Modular Laboratory Hall Effect Thruster

    Science.gov (United States)

    Lee, Ty Davis

    Electric propulsion technologies promise to revolutionize access to space, opening the door for mission concepts unfeasible by traditional propulsion methods alone. The Hall effect thruster is a relatively high thrust, moderate specific impulse electric propulsion device that belongs to the class of electrostatic thrusters. Hall effect thrusters benefit from an extensive flight history, and offer significant performance and cost advantages when compared to other forms of electric propulsion. Ongoing research on these devices includes the investigation of mechanisms that tend to decrease overall thruster efficiency, as well as the development of new techniques to extend operational lifetimes. This thesis is primarily concerned with the design and construction of a Small Modular Laboratory Hall Effect Thruster (SMLHET), and its operation on argon propellant gas. Particular attention was addressed at low-cost, modular design principles, that would facilitate simple replacement and modification of key thruster parts such as the magnetic circuit and discharge channel. This capability is intended to facilitate future studies of device physics such as anomalous electron transport and magnetic shielding of the channel walls, that have an impact on thruster performance and life. Preliminary results demonstrate SMLHET running on argon in a manner characteristic of Hall effect thrusters, additionally a power balance method was utilized to estimate thruster performance. It is expected that future thruster studies utilizing heavier though more expensive gases like xenon or krypton, will observe increased efficiency and stability.

  15. June 1992 Hall B collaboation meeting

    International Nuclear Information System (INIS)

    Dennis, L.

    1992-01-01

    The Hall B collaboration meeting at the CEBAF 1992 Summer Workshop consisted of technical and physics working group meetings, a special beam line devices working group meeting the first meeting of the membership committee, a technical representatives meeting and a full collaboration meeting. Highlights of these meetings are presented in this report

  16. Chapin Hall Projects and Publications. Autumn 1999.

    Science.gov (United States)

    Chicago Univ., IL. Chapin Hall Center for Children.

    This guide chronicles the ongoing work and writings of the Chapin Hall Center for Children at the University of Chicago, a policy research center dedicated to bringing sound information, rigorous analyses, innovative ideas, and an independent, multidisciplinary perspective to bear on policies and programs affecting children. This guide, organized…

  17. Quantum Hall Conductivity and Topological Invariants

    Science.gov (United States)

    Reyes, Andres

    2001-04-01

    A short survey of the theory of the Quantum Hall effect is given emphasizing topological aspects of the quantization of the conductivity and showing how topological invariants can be derived from the hamiltonian. We express these invariants in terms of Chern numbers and show in precise mathematical terms how this relates to the Kubo formula.

  18. Room acoustic properties of concert halls

    DEFF Research Database (Denmark)

    Gade, Anders Christian

    1996-01-01

    A large database of values of various room acoustic parameters has provided the basis for statistical analyses of how and how much the acoustic properties of concert halls are influenced by their size, shape, and absorption area (as deduced from measured reverberation time). The data have been...

  19. Pseudospin anisotropy classification of quantum Hall ferromagnets

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Tomáš; MacDonald, A. H.

    2000-01-01

    Roč. 63, č. 3 (2000), s. 035305-1 - 035305-9 ISSN 0163-1829 R&D Projects: GA ČR GA202/98/0085 Institutional research plan: CEZ:AV0Z1010914 Keywords : quantum Hall ferromagnets * anisotropy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.065, year: 2000

  20. Anomalous Hall effect in disordered multiband metals

    Czech Academy of Sciences Publication Activity Database

    Kovalev, A.A.; Sinova, Jairo; Tserkovnyak, Y.

    2010-01-01

    Roč. 105, č. 3 (2010), 036601/1-036601/4 ISSN 0031-9007 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.621, year: 2010

  1. Anomalous Hall conductivity: Local orbitals approach

    Czech Academy of Sciences Publication Activity Database

    Středa, Pavel

    2010-01-01

    Roč. 82, č. 4 (2010), 045115/1-045115/9 ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * Berry phase correction * orbital polarization momentum Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.772, year: 2010

  2. Quantization and hall effect: necessities and difficulties

    International Nuclear Information System (INIS)

    Ahmed Bouketir; Hishamuddin Zainuddin

    1999-01-01

    The quantization procedure is a necessary tool for a proper understanding of many interesting quantum phenomena in modern physics. In this note, we focus on geometrical framework for such procedures, particularly the group-theoretic approach and their difficulties. Finally we look through the example of Hall effect as a quantized macroscopic phenomenon with group-theoretic quantization approach. (author)

  3. Spin Hall effect on a noncommutative space

    International Nuclear Information System (INIS)

    Ma Kai; Dulat, Sayipjamal

    2011-01-01

    We study the spin-orbital interaction and the spin Hall effect of an electron moving on a noncommutative space under the influence of a vector potential A(vector sign). On a noncommutative space, we find that the commutator between the vector potential A(vector sign) and the electric potential V 1 (r(vector sign)) of the lattice induces a new term, which can be treated as an effective electric field, and the spin Hall conductivity obtains some correction. On a noncommutative space, the spin current and spin Hall conductivity have distinct values in different directions, and depend explicitly on the noncommutative parameter. Once this spin Hall conductivity in different directions can be measured experimentally with a high level of accuracy, the data can then be used to impose bounds on the value of the space noncommutativity parameter. We have also defined a new parameter, σ=ρθ (ρ is the electron concentration, θ is the noncommutativity parameter), which can be measured experimentally. Our approach is based on the Foldy-Wouthuysen transformation, which gives a general Hamiltonian of a nonrelativistic electron moving on a noncommutative space.

  4. Prospect of quantum anomalous Hall and quantum spin Hall effect in doped kagome lattice Mott insulators.

    Science.gov (United States)

    Guterding, Daniel; Jeschke, Harald O; Valentí, Roser

    2016-05-17

    Electronic states with non-trivial topology host a number of novel phenomena with potential for revolutionizing information technology. The quantum anomalous Hall effect provides spin-polarized dissipation-free transport of electrons, while the quantum spin Hall effect in combination with superconductivity has been proposed as the basis for realizing decoherence-free quantum computing. We introduce a new strategy for realizing these effects, namely by hole and electron doping kagome lattice Mott insulators through, for instance, chemical substitution. As an example, we apply this new approach to the natural mineral herbertsmithite. We prove the feasibility of the proposed modifications by performing ab-initio density functional theory calculations and demonstrate the occurrence of the predicted effects using realistic models. Our results herald a new family of quantum anomalous Hall and quantum spin Hall insulators at affordable energy/temperature scales based on kagome lattices of transition metal ions.

  5. Digital technology impacts on the Arnhem transfer hall structural design

    NARCIS (Netherlands)

    Van de Straat, R.; Hofman, S.; Coenders, J.L.; Paul, J.C.

    2015-01-01

    The new Transfer Hall in Arnhem is one of the key projects to prepare the Dutch railways for the increased future demands for capacity. UNStudio developed a master plan in 1996 for the station area of which the completion of the Transfer Hall in 2015 will be a final milestone. The Transfer Hall is a

  6. Magnetoresistance in quantum Hall metals due to Pancharatnam ...

    Indian Academy of Sciences (India)

    Abstract. We derive the trial Hall resistance formula for the quantum Hall metals to address both the integer and fractional quantum Hall effects. Within the degenerate (and crossed) Landau levels, and in the presence of changing magnetic field strength, one can invoke two physical processes responsible for the electron ...

  7. Destruction of the fractional quantum Hall effect by disorder

    International Nuclear Information System (INIS)

    Laughlin, R.B.

    1985-07-01

    It is suggested that Hall steps in the fractional quantum Hall effect are physically similar to those in the ordinary quantum Hall effect. This proposition leads to a simple scaling diagram containing a new type of fixed point, which is identified with the destruction of the fractional states by disorder. 15 refs., 3 figs

  8. A Hall probe technique for characterizing high-temperature superconductors

    International Nuclear Information System (INIS)

    Zhang, J.; Sheldon, P.; Ahrenkiel, R.K.

    1992-01-01

    Thin-film GaAs Hall probes were fabricated by molecular beam epitaxy technology. A contactless technique was developed to characterize thin-film, high-temperature superconducting (HTSC) materials. The Hall probes detected the ac magnetic flux penetration through the high-temperature superconducting materials. The Hall detector has advantages over the mutual inductance magnetic flux detector

  9. Spin-singlet hierarchy in the fractional quantum Hall effect

    OpenAIRE

    Ino, Kazusumi

    1999-01-01

    We show that the so-called permanent quantum Hall states are formed by the integer quantum Hall effects on the Haldane-Rezayi quantum Hall state. Novel conformal field theory description along with this picture is deduced. The odd denominator plateaux observed around $\

  10. Saddle Slow Manifolds and Canard Orbits in [Formula: see text] and Application to the Full Hodgkin-Huxley Model.

    Science.gov (United States)

    Hasan, Cris R; Krauskopf, Bernd; Osinga, Hinke M

    2018-04-19

    Many physiological phenomena have the property that some variables evolve much faster than others. For example, neuron models typically involve observable differences in time scales. The Hodgkin-Huxley model is well known for explaining the ionic mechanism that generates the action potential in the squid giant axon. Rubin and Wechselberger (Biol. Cybern. 97:5-32, 2007) nondimensionalized this model and obtained a singularly perturbed system with two fast, two slow variables, and an explicit time-scale ratio ε. The dynamics of this system are complex and feature periodic orbits with a series of action potentials separated by small-amplitude oscillations (SAOs); also referred to as mixed-mode oscillations (MMOs). The slow dynamics of this system are organized by two-dimensional locally invariant manifolds called slow manifolds which can be either attracting or of saddle type.In this paper, we introduce a general approach for computing two-dimensional saddle slow manifolds and their stable and unstable fast manifolds. We also develop a technique for detecting and continuing associated canard orbits, which arise from the interaction between attracting and saddle slow manifolds, and provide a mechanism for the organization of SAOs in [Formula: see text]. We first test our approach with an extended four-dimensional normal form of a folded node. Our results demonstrate that our computations give reliable approximations of slow manifolds and canard orbits of this model. Our computational approach is then utilized to investigate the role of saddle slow manifolds and associated canard orbits of the full Hodgkin-Huxley model in organizing MMOs and determining the firing rates of action potentials. For ε sufficiently large, canard orbits are arranged in pairs of twin canard orbits with the same number of SAOs. We illustrate how twin canard orbits partition the attracting slow manifold into a number of ribbons that play the role of sectors of rotations. The upshot is that we

  11. Integrability and Linearizability of the Lotka-Volterra System with a Saddle Point with Rational Hyperbolicity Ratio

    Science.gov (United States)

    Gravel, Simon; Thibault, Pierre

    In this paper, we consider normalizability, integrability and linearizability properties of the Lotka-Volterra system in the neighborhood of a singular point with eigenvalues 1 and - λ. The results are obtained by generalizing and expanding two methods already known: the power expansion of the first integral or of the linearizing transformation and the transformation of the saddle into a node. With these methods we find conditions that are valid for λ∈ R+ or λ∈ Q. These conditions will allow us to find all the integrable and linearizable systems for λ= {p}/{2} and {2}/{p} with p∈ N+.

  12. Topological honeycomb magnon Hall effect: A calculation of thermal Hall conductivity of magnetic spin excitations

    Energy Technology Data Exchange (ETDEWEB)

    Owerre, S. A., E-mail: solomon@aims.ac.za [African Institute for Mathematical Sciences, 6 Melrose Road, Muizenberg, Cape Town 7945, South Africa and Perimeter Institute for Theoretical Physics, 31 Caroline St. N., Waterloo, Ontario N2L 2Y5 (Canada)

    2016-07-28

    Quite recently, the magnon Hall effect of spin excitations has been observed experimentally on the kagome and pyrochlore lattices. The thermal Hall conductivity κ{sup xy} changes sign as a function of magnetic field or temperature on the kagome lattice, and κ{sup xy} changes sign upon reversing the sign of the magnetic field on the pyrochlore lattice. Motivated by these recent exciting experimental observations, we theoretically propose a simple realization of the magnon Hall effect in a two-band model on the honeycomb lattice. The magnon Hall effect of spin excitations arises in the usual way via the breaking of inversion symmetry of the lattice, however, by a next-nearest-neighbour Dzyaloshinsky-Moriya interaction. We find that κ{sup xy} has a fixed sign for all parameter regimes considered. These results are in contrast to the Lieb, kagome, and pyrochlore lattices. We further show that the low-temperature dependence on the magnon Hall conductivity follows a T{sup 2} law, as opposed to the kagome and pyrochlore lattices. These results suggest an experimental procedure to measure thermal Hall conductivity within a class of 2D honeycomb quantum magnets and ultracold atoms trapped in a honeycomb optical lattice.

  13. Diagnostics Systems for Permanent Hall Thrusters Development

    Science.gov (United States)

    Ferreira, Jose Leonardo; Soares Ferreira, Ivan; Santos, Jean; Miranda, Rodrigo; Possa, M. Gabriela

    This work describes the development of Permanent Magnet Hall Effect Plasma Thruster (PHALL) and its diagnostic systems at The Plasma Physics Laboratory of University of Brasilia. The project consists on the construction and characterization of plasma propulsion engines based on the Hall Effect. Electric thrusters have been employed in over 220 successful space missions. Two types stand out: the Hall-Effect Thruster (HET) and the Gridded Ion Engine (GIE). The first, which we deal with in this project, has the advantage of greater simplicity of operation, a smaller weight for the propulsion subsystem and a longer shelf life. It can operate in two configurations: magnetic layer and anode layer, the difference between the two lying in the positioning of the anode inside the plasma channel. A Hall-Effect Thruster-HET is a type of plasma thruster in which the propellant gas is ionized and accelerated by a magneto hydrodynamic effect combined with electrostatic ion acceleration. So the essential operating principle of the HET is that it uses a J x B force and an electrostatic potential to accelerate ions up to high speeds. In a HET, the attractive negative charge is provided by electrons at the open end of the Thruster instead of a grid, as in the case of the electrostatic ion thrusters. A strong radial magnetic field is used to hold the electrons in place, with the combination of the magnetic field and the electrostatic potential force generating a fast circulating electron current, the Hall current, around the axis of the Thruster, mainly composed by drifting electrons in an ion plasma background. Only a slow axial drift towards the anode occurs. The main attractive features of the Hall-Effect Thruster are its simple design and operating principles. Most of the Hall-Effect Thrusters use electromagnet coils to produce the main magnetic field responsible for plasma generation and acceleration. In this paper we present a different new concept, a Permanent Magnet Hall

  14. Valley-chiral quantum Hall state in graphene superlattice structure

    Science.gov (United States)

    Tian, H. Y.; Tao, W. W.; Wang, J.; Cui, Y. H.; Xu, N.; Huang, B. B.; Luo, G. X.; Hao, Y. H.

    2016-05-01

    We theoretically investigate the quantum Hall effect in a graphene superlattice (GS) system, in which the two valleys of graphene are coupled together. In the presence of a perpendicular magnetic field, an ordinary quantum Hall effect is found with the sequence σxy=ν e^2/h(ν=0,+/-1,+/-2,\\cdots) . At the zeroth Hall platform, a valley-chiral Hall state stemming from the single K or K' valley is found and it is localized only on one sample boundary contributing to the longitudinal conductance but not to the Hall conductivity. Our findings may shed light on the graphene-based valleytronics applications.

  15. Accurate micro Hall effect measurements on scribe line pads

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Petersen, Dirch Hjorth; Wang, Fei

    2009-01-01

    Hall mobility and sheet carrier density are important parameters to monitor in advanced semiconductor production. If micro Hall effect measurements are done on small pads in scribe lines, these parameters may be measured without using valuable test wafers. We report how Hall mobility can...... be extracted from micro four-point measurements performed on a rectangular pad. The dimension of the investigated pad is 400 × 430 ¿m2, and the probe pitches range from 20 ¿m to 50 ¿m. The Monte Carlo method is used to find the optimal way to perform the Hall measurement and extract Hall mobility most...

  16. Giant photonic Hall effect in magnetophotonic crystals.

    Science.gov (United States)

    Merzlikin, A M; Vinogradov, A P; Inoue, M; Granovsky, A B

    2005-10-01

    We have considered a simple, square, two-dimensional (2D) PC built of a magneto-optic matrix with square holes. It is shown that using such a magnetophotonic crystal it is possible to deflect a light beam at very large angles by applying a nonzero external magnetic field. The effect is called the giant photonic Hall effect (GPHE) or the magnetic superprism effect. The GPHE is based on magneto-optical properties, as is the photonic Hall effect [B. A. van Tiggelen and G. L. J. A. Rikken, in, edited by V. M. Shalaev (Springer-Verlag, Berlin, 2002), p. 275]; however GPHE is not caused by asymmetrical light scattering but rather by the influence of an external magnetic field on the photonic band structure.

  17. Assessment of elevator rope using Hall Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong O; Yoon, Woon Ha; Son, Young Ho; Kim, Jung Woo [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Lee, Jong Ku [Pukyung National University, Pusan (Korea, Republic of)

    2003-07-01

    Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4 mm and 1 mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2 mm in depth at 4 mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.

  18. Assesment of elevator rope using hall sensor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong O; Yoon, Woon Ha; Son, Young Ho [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Kim, Jung Woo; Lee, Jong Ku [Pukyong National University, Pusan (Korea, Republic of)

    2003-05-15

    Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4mm and 1mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2mm in depth at 4mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.

  19. Infinite symmetry in the quantum Hall effect

    Directory of Open Access Journals (Sweden)

    Lütken C.A.

    2014-04-01

    Full Text Available The new states of matter and concomitant quantum critical phenomena revealed by the quantum Hall effect appear to be accompanied by an emergent modular symmetry. The extreme rigidity of this infinite symmetry makes it easy to falsify, but two decades of experiments have failed to do so, and the location of quantum critical points predicted by the symmetry is in increasingly accurate agreement with scaling experiments. The symmetry severely constrains the structure of the effective quantum field theory that encodes the low energy limit of quantum electrodynamics of 1010 charges in two dirty dimensions. If this is a non-linear σ-model the target space is a torus, rather than the more familiar sphere. One of the simplest toroidal models gives a critical (correlation length exponent that agrees with the value obtained from numerical simulations of the quantum Hall effect.

  20. Stuart Hall and Cultural Studies, circa 1983

    Directory of Open Access Journals (Sweden)

    Ann Curthoys

    2017-11-01

    Full Text Available Stuart Hall sought to internationalise theoretical debates and to create Cultural Studies as interdisciplinary. We chart his theoretical journey through a detailed examination of a series of lectures delivered in 1983 and now published for the first time. In these lectures, he discusses theorists such as E.P. Thompson, Raymond Williams, Louis Althusser, Levi Strauss and Antonio Gramsci, and explores the relationship between ideas and social structure, the specificities of class and race, and the legacies of slavery. We note his turn towards metaphors of divergence and dispersal and highlight how autobiographical and deeply personal Hall is in these lectures, especially in his ego histoire moment of traumatic memory recovery.

  1. Hall magnetohydrodynamics: Conservation laws and Lyapunov stability

    International Nuclear Information System (INIS)

    Holm, D.D.

    1987-01-01

    Hall electric fields produce circulating mass flow in confined ideal-fluid plasmas. The conservation laws, Hamiltonian structure, equilibrium state relations, and Lyapunov stability conditions are presented here for ideal Hall magnetohydrodynamics (HMHD) in two and three dimensions. The approach here is to use the remarkable array of nonlinear conservation laws for HMHD that follow from its Hamiltonian structure in order to construct explicit Lyapunov functionals for the HMHD equilibrium states. In this way, the Lyapunov stability analysis provides classes of HMHD equilibria that are stable and whose linearized initial-value problems are well posed (in the sense of possessing continuous dependence on initial conditions). Several examples are discussed in both two and three dimensions

  2. Music hall Markneukirchen; Musikhalle in Markneukirchen

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1996-01-01

    The article presents the new building of the music hall Markneukirchen. From the planned use of the building result very high demands on the ventilation system in order to keep to a sound power level of less than 30 dB(A) in the hall. The building services are dealt with using numerous flowsheets and diagrams: Heat supply, ventilation system, sanitary system, building management, instrumentation and control, electric and lighting systems. (BWI) [Deutsch] Der vorliegende Beitrag stellt den Neubau der Musikhalle Markneukirchen vor. Durch das Nutzungskonzept ergeben sich fuer die Einhaltung eines Schalleistungspegels von weniger als 30 dB(A) im Saalbereich an die Lueftungsanlage sehr hohe Ansprueche. Es werden die raumlufttechnischen Anlagen anhand zahlreicher Flussbilder und Abbildungen vorgestellt: Waermeversorgung, Lueftungstechnik, Sanitaertechnik, Gebaeudeleit- und MSR-Technik, Elektro- und Lichttechnik. (BWI)

  3. Theory of fractional quantum hall effect

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.

    1985-08-01

    A theory of the Fractional Quantum Hall Effect is constructed based on magnetic flux fractionization, which lead to instability of the system against selfcompression. A theorem is proved stating that arbitrary potentials fail to lift a specific degeneracy of the Landau level. For the case of 1/3 fractional filling a model 3-particles interaction is constructed breaking the symmetry. The rigid 3-particles wave function plays the role of order parameter. In a BCS type of theory the gap in the single particles spectrum is produced by the 3-particles interaction. The mean field critical behaviour and critical parameters are determined as well as the Ginsburg-Landau equation coefficients. The Hall conductivity is calculated from the first principles and its temperature dependence is found. The simultaneous tunnelling of 3,5,7 etc. electrons and quantum interference effects are predicted. (author)

  4. Coulomb blockade in hierarchical quantum Hall droplets

    International Nuclear Information System (INIS)

    Cappelli, Andrea; Georgiev, Lachezar S; Zemba, Guillermo R

    2009-01-01

    The degeneracy of energy levels in a quantum dot of Hall fluid, leading to conductance peaks, can be readily derived from the partition functions of conformal field theory. Their complete expressions can be found for Hall states with both Abelian and non-Abelian statistics, upon adapting known results for the annulus geometry. We analyze the Abelian states with hierarchical filling fractions, ν = m/(mp ± 1), and find a non-trivial pattern of conductance peaks. In particular, each one of them occurs with a characteristic multiplicity, which is due to the extended symmetry of the m-folded edge. Experimental tests of the multiplicity can shed more light on the dynamics of this composite edge. (fast track communication)

  5. Assessment of elevator rope using Hall Sensor

    International Nuclear Information System (INIS)

    Lee, Jong O; Yoon, Woon Ha; Son, Young Ho; Kim, Jung Woo; Lee, Jong Ku

    2003-01-01

    Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4 mm and 1 mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2 mm in depth at 4 mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.

  6. Assesment of elevator rope using hall sensor

    International Nuclear Information System (INIS)

    Lee, Jong O; Yoon, Woon Ha; Son, Young Ho; Kim, Jung Woo; Lee, Jong Ku

    2003-01-01

    Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4mm and 1mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2mm in depth at 4mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.

  7. Judy Estes Hall (1940-2015).

    Science.gov (United States)

    Sammons, Morgan T; Boucher, Andrew

    2016-01-01

    Presents an obituary for Judy Estes Hall, who passed away on November 24, 2015. Hall served as the Executive Officer of the National Register of Health Service Psychologists until her retirement in 2013. She is a recognized expert in the development of education and training standards for the profession of psychology, she also made significant contributions in the field of international psychology, where she was a renowned expert in cross-national credentialing and an advocate for commonality in licensing standards. She was the coauthor of one edited volume and author of more than 60 journal articles, book chapters, and professional publications. A passionate advocate for the advancement of women in psychology, a devoted mother and grandmother, a connoisseur of wine and international traveler extraordinaire, she touched the personal and professional lives of many. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  8. Homotopy arguments for quantized Hall conductivity

    CERN Document Server

    Richter, T

    2002-01-01

    Using the strong localization bounds obtained by the Aizenman-Molcanov method for a particle in a magnetic field and a disordered potential, we show that the zero-temperature Hall conductivity of a gas of such particles is quantized and constant as long as both Fermi energy and disorder coupling parameter vary in a region of strong localization of the corresponding two-dimensional phase diagram.

  9. SPS beam to the West Hall

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    One of the two target stations feeding the West Hall (see Annual Report 1976). After the proton beam was split into three branches, the outer two were directed on to targets in the cast iron shielding box, the centre one passing through the box to another target station downstream. Five different targets could be put in each beam, controlled by the mechanism seen on top.

  10. Anomalous hall effect in ferromagnetic semiconductors

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Tomáš; Niu, Q.; MacDonald, A. H.

    2002-01-01

    Roč. 88, č. 20 (2002), s. 207208-1-207208-4 ISSN 0031-9007 R&D Projects: GA ČR GA202/02/0912; GA MŠk OC P5.10 Institutional research plan: CEZ:AV0Z1010914 Keywords : ferromagnetic semiconductors * anomalous Hall effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.323, year: 2002

  11. A hall for assembly and cryogenic tests

    International Nuclear Information System (INIS)

    Beaunier, J.; Buhler, S.; Caruette, A.; Chevrollier, R.; Junquera, T.; Le Scornet, J.C.

    1999-01-01

    Cryodrome, an assembly hall and the testing ground for cryogenic equipment and R and D experiments for the superconducting cavities is going to be transformed for its future missions. The cryogenic utilities, especially the He low pressure pumping capacity, was rearranged and extended to a new area. Space was provided to install CRYHOLAB, a new horizontal cryostat for cavity testing. Automatic control and supervision of the utilities and the experimental area are rebuilt and updated. (authors)

  12. Generic superweak chaos induced by Hall effect

    Science.gov (United States)

    Ben-Harush, Moti; Dana, Itzhack

    2016-05-01

    We introduce and study the "kicked Hall system" (KHS), i.e., charged particles periodically kicked in the presence of uniform magnetic (B ) and electric (E ) fields that are perpendicular to each other and to the kicking direction. We show that for resonant values of B and E and in the weak-chaos regime of sufficiently small nonintegrability parameter κ (the kicking strength), there exists a generic family of periodic kicking potentials for which the Hall effect from B and E significantly suppresses the weak chaos, replacing it by "superweak" chaos (SWC). This means that the system behaves as if the kicking strength were κ2 rather than κ . For E =0 , SWC is known to be a classical fingerprint of quantum antiresonance, but it occurs under much less generic conditions, in particular only for very special kicking potentials. Manifestations of SWC are a decrease in the instability of periodic orbits and a narrowing of the chaotic layers, relative to the ordinary weak-chaos case. Also, for global SWC, taking place on an infinite "stochastic web" in phase space, the chaotic diffusion on the web is much slower than the weak-chaos one. Thus, the Hall effect can be relatively stabilizing for small κ . In some special cases, the effect is shown to cause ballistic motion for almost all parameter values. The generic global SWC on stochastic webs in the KHS appears to be the two-dimensional closest analog to the Arnol'd web in higher dimensional systems.

  13. Anode Fall Formation in a Hall Thruster

    International Nuclear Information System (INIS)

    Dorf, Leonid A.; Raitses, Yevgeny F.; Smirnov, Artem N.; Fisch, Nathaniel J.

    2004-01-01

    As was reported in our previous work, accurate, nondisturbing near-anode measurements of the plasma density, electron temperature, and plasma potential performed with biased and emissive probes allowed the first experimental identification of both electron-repelling (negative anode fall) and electron-attracting (positive anode fall) anode sheaths in Hall thrusters. An interesting new phenomenon revealed by the probe measurements is that the anode fall changes from positive to negative upon removal of the dielectric coating, which appears on the anode surface during the course of Hall thruster operation. As reported in the present work, energy dispersion spectroscopy analysis of the chemical composition of the anode dielectric coating indicates that the coating layer consists essentially of an oxide of the anode material (stainless steel). However, it is still unclear how oxygen gets into the thruster channel. Most importantly, possible mechanisms of anode fall formation in a Hall thruster with a clean and a coated anodes are analyzed in this work; practical implication of understanding the general structure of the electron-attracting anode sheath in the case of a coated anode is also discussed

  14. Josephson tunneling in bilayer quantum Hall system

    International Nuclear Information System (INIS)

    Ezawa, Z.F.; Tsitsishvili, G.; Sawada, A.

    2012-01-01

    A Bose–Einstein condensation is formed by composite bosons in the quantum Hall state. A composite boson carries the fundamental charge (−e). We investigate Josephson tunneling of such charges in the bilayer quantum Hall system at the total filling ν=1. We show the existence of the critical current for the tunneling current to be coherent and dissipationless. Our results explain recent experiments due to [L. Tiemann, Y. Yoon, W. Dietsche, K. von Klitzing, W. Wegscheider, Phys. Rev. B 80 (2009) 165120] and due to [Y. Yoon, L. Tiemann, S. Schmult, W. Dietsche, K. von Klitzing, Phys. Rev. Lett. 104 (2010) 116802]. We predict also how the critical current changes as the sample is tilted in the magnetic field. -- Highlights: ► Composite bosons undergo Bose–Einstein condensation to form the bilayer quantum Hall state. ► A composite boson is a single electron bound to a flux quantum and carries one unit charge. ► Quantum coherence develops due to the condensation. ► Quantum coherence drives the supercurrent in each layer and the tunneling current. ► There exists the critical input current so that the tunneling current is coherent and dissipationless.

  15. Familial Pallister-Hall in adulthood.

    Science.gov (United States)

    Talsania, Mitali; Sharma, Rohan; Sughrue, Michael E; Scofield, R Hal; Lim, Jonea

    2017-10-01

    Pallister Hall syndrome is autosomal dominant disorder usually diagnosed in infants and children. Current diagnostic criteria include presence of hypothalamic hamartoma, post axial polydactyly and positive family history, but the disease has variable manifestations. Herein we report Pallister Hall syndrome diagnosed in a family where both patients were adults. A 59 year old man developed seizures 4 years prior to our evaluation of him, at which time imaging showed a hypothalamic hamartoma. The seizures were controlled medically. He did well until he had visual changes after a traumatic head injury. Repeat MRI showed slight expansion of the mass with formal visual field testing demonstrating bitemporal hemianopsia. There was no evidence of pituitary dysfunction except for large urine volume. He underwent surgery to debulk the hamartoma and the visual field defects improved. There was no hypopituitarism post-operatively, and the polydyspia resolved. His 29 year old daughter also had seizures and hypothalamic hamartoma. Both patients had had polydactyly with prior surgical correction in childhood. The daughter underwent genetic testing, which revealed a previously undescribed heterozygous single base pair deletion in exon 13 of the GLI3 gene causing a frameshift mutation. Further investigation into family history revealed multiple members in previous generations with polydactyly and/or seizures. Pallister-Hall syndrome is caused by an inherited autosomal dominant or de novo mutation in GLI3 gene. This rare syndrome has not had prevalence defined, however. Generally, diagnoses are made in the pediatric population. Our report adds to the few cases detected in adulthood.

  16. Enhanced Nonadiabaticity in Vortex Cores due to the Emergent Hall Effect

    KAUST Repository

    Bisig, André

    2017-01-04

    We present a combined theoretical and experimental study, investigating the origin of the enhanced nonadiabaticity of magnetic vortex cores. Scanning transmission x-ray microscopy is used to image the vortex core gyration dynamically to measure the nonadiabaticity with high precision, including a high confidence upper bound. We show theoretically, that the large nonadiabaticity parameter observed experimentally can be explained by the presence of local spin currents arising from a texture induced emergent Hall effect. This study demonstrates that the magnetic damping α and nonadiabaticity parameter β are very sensitive to the topology of the magnetic textures, resulting in an enhanced ratio (β/α>1) in magnetic vortex cores or Skyrmions.

  17. Enhanced Nonadiabaticity in Vortex Cores due to the Emergent Hall Effect

    KAUST Repository

    Bisig, André ; Akosa, Collins Ashu; Moon, Jung-Hwan; Rhensius, Jan; Moutafis, Christoforos; von Bieren, Arndt; Heidler, Jakoba; Kiliani, Gillian; Kammerer, Matthias; Curcic, Michael; Weigand, Markus; Tyliszczak, Tolek; Van Waeyenberge, Bartel; Stoll, Hermann; Schü tz, Gisela; Lee, Kyung-Jin; Manchon, Aurelien; Klä ui, Mathias

    2017-01-01

    We present a combined theoretical and experimental study, investigating the origin of the enhanced nonadiabaticity of magnetic vortex cores. Scanning transmission x-ray microscopy is used to image the vortex core gyration dynamically to measure the nonadiabaticity with high precision, including a high confidence upper bound. We show theoretically, that the large nonadiabaticity parameter observed experimentally can be explained by the presence of local spin currents arising from a texture induced emergent Hall effect. This study demonstrates that the magnetic damping α and nonadiabaticity parameter β are very sensitive to the topology of the magnetic textures, resulting in an enhanced ratio (β/α>1) in magnetic vortex cores or Skyrmions.

  18. Commemorative Symposium on the Hall Effect and its Applications

    CERN Document Server

    Westgate, C

    1980-01-01

    In 1879, while a graduate student under Henry Rowland at the Physics Department of The Johns Hopkins University, Edwin Herbert Hall discovered what is now universally known as the Hall effect. A symposium was held at The Johns Hopkins University on November 13, 1979 to commemorate the lOOth anniversary of the discovery. Over 170 participants attended the symposium which included eleven in­ vited lectures and three speeches during the luncheon. During the past one hundred years, we have witnessed ever ex­ panding activities in the field of the Hall effect. The Hall effect is now an indispensable tool in the studies of many branches of condensed matter physics, especially in metals, semiconductors, and magnetic solids. Various components (over 200 million!) that utilize the Hall effect have been successfully incorporated into such devices as keyboards, automobile ignitions, gaussmeters, and satellites. This volume attempts to capture the important aspects of the Hall effect and its applications. It includes t...

  19. Experimental test of 200 W Hall thruster with titanium wall

    Science.gov (United States)

    Ding, Yongjie; Sun, Hezhi; Peng, Wuji; Xu, Yu; Wei, Liqiu; Li, Hong; Li, Peng; Su, Hongbo; Yu, Daren

    2017-05-01

    We designed a 200 W Hall thruster based on the technology of pushing down a magnetic field with two permanent magnetic rings. Boron nitride (BN) is an important insulating wall material for Hall thrusters. The discharge characteristics of the designed Hall thruster were studied by replacing BN with titanium (Ti). Experimental results show that the designed Hall thruster can discharge stably for a long time under a Ti channel. Experiments were performed to determine whether the channel and cathode are electrically connected. When the channel wall and cathode are insulated, the divergence angle of the plume increases, but the performance of the Hall thruster is improved in terms of thrust, specific impulse, anode efficiency, and thrust-to-power ratio. Ti exhibits a powerful antisputtering capability, a low emanation rate of gas, and a large structural strength, making it a potential candidate wall material in the design of low-power Hall thrusters.

  20. Strontium isotopic and trace element geochemistry of the saddle mountains and Grande Ronde Basalts of the Columbia River Basalt Group

    International Nuclear Information System (INIS)

    Nelson, D.O.

    1980-01-01

    The Columbia River Basalt (CRB) group displays significant variations in major and trace element and Sr isotopic compositions. These compositions reflect complex and variable origins for the CRB magmas. Among the most varied is the Saddle Mountains Basalt (SMB) in which Sr ratios vary from 0.7078 to 0.7147 +- 0.002. The higher ratios reflect contamination through consistent correlations with major element compositions. Modeling suggests contamination by assimilation of 4.4 to 9.4 wt % of radiogenic crustal rocks. High delta 18 O values (up to +7.68 per mil) support the model. Age and field relations suggest that the contamination flowrocks are not the result of progressive contamination of a single magma, but rather reflect the contamination of independent magmas during this ascent

  1. Unstable Modes and Order Parameters of Bistable Signaling Pathways at Saddle-Node Bifurcations: A Theoretical Study Based on Synergetics

    Directory of Open Access Journals (Sweden)

    Till D. Frank

    2016-01-01

    Full Text Available Mathematical modeling has become an indispensable part of systems biology which is a discipline that has become increasingly popular in recent years. In this context, our understanding of bistable signaling pathways in terms of mathematical modeling is of particular importance because such bistable components perform crucial functions in living cells. Bistable signaling pathways can act as switches or memory functions and can determine cell fate. In the present study, properties of mathematical models of bistable signaling pathways are examined from the perspective of synergetics, a theory of self-organization and pattern formation founded by Hermann Haken. At the heart of synergetics is the concept of so-called unstable modes or order parameters that determine the behavior of systems as a whole close to bifurcation points. How to determine these order parameters for bistable signaling pathways at saddle-node bifurcation points is shown. The procedure is outlined in general and an explicit example is worked out in detail.

  2. Slow light effect with high group index and wideband by saddle-like mode in PC-CROW

    Science.gov (United States)

    Wan, Yong; Jiang, Li-Jun; Xu, Sheng; Li, Meng-Xue; Liu, Meng-Nan; Jiang, Cheng-Yi; Yuan, Feng

    2018-04-01

    Slow light with high group index and wideband is achieved in photonic crystal coupled-resonator optical waveguides (PC-CROWs). According to the eye-shaped scatterers and various microcavities, saddle-like curves between the normalized frequency f and wave number k can be obtained by adjusting the parameters of the scatterers, parameters of the coupling microcavities, and positions of the scatterers. Slow light with decent flat band and group index can then be achieved by optimizing the parameters. Simulations prove that the maximal value of the group index is > 104, and the normalized delay bandwidth product within a new varying range of n g > 102 or n g > 103 can be a new and effective criterion of evaluation for the slow light in PC-CROWs.

  3. Electron Transfer and Geometric Conversion of Co-NO Moiety in Saddled Porphyrins: Implications for Trigger Role of Tetrapyrrole Distortion.

    Science.gov (United States)

    Tang, Min; Yang, Yan; Zhang, Shaowei; Chen, Jiafu; Zhang, Jian; Zhou, Zaichun; Liu, Qiuhua

    2018-01-02

    The electrons of NO and Co are strongly delocalized in normal {Co-NO} 8 species. In this work, {Co-NO} 8 complexes are induced to convert from (Co II ) +• -NO • to Co III -NO - by a core contraction of 0.06 Å in saddled cobalt(II) porphyrins. This intramolecular electron transfer mechanism indicates that nonplanarity of porphyrin is involved in driving conversion of the NO units from electrophilic NO • as a bent geometry to nucleophilic NO - as a linear geometry. This implies that distortion acts as a trigger in enzymes containing tetrapyrrole. The electronic behaviors of the Co II ions and Co-NO moieties were confirmed by X-ray crystallography, EPR spectroscopy, theoretical calculation, UV-vis and IR spectroscopy, and electrochemistry.

  4. Risk factors for saddle-related skin lesions on elephants used in the tourism industry in Thailand.

    Science.gov (United States)

    Magda, Scarlett; Spohn, Olivia; Angkawanish, Taweepoke; Smith, Dale A; Pearl, David L

    2015-05-19

    Lesions related to working conditions and improper saddle design are a concern for a variety of working animals including elephants. The objectives of the present study were to determine the prevalence of cutaneous lesions in anatomic regions (i.e., neck, girth, back, tail) in contact with saddle-related equipment among elephants in Thailand working in the tourism industry, and to identify potential risk factors associated with these lesions. Data for this cross-sectional study were collected between May 2007 and July 2007 on 194 elephants from 18 tourism camps across Thailand. There was a high prevalence (64.4 %; 95 % CI 57.3 - 71.2) of active lesions, most often located on the back region. Using multilevel multivariable logistic regression modelling containing a random intercept for camp we identified the following risk factors: increasing elephant age, the use of rice sacks as padding material in contact with the skin, and the provision of a break for the elephants. Working hours had a quadratic relationship with the log odds of an active lesion where the probability of an active lesion initially increased with the number of working hours per day and then declined possibly reflecting a "healthy worker" bias where only animals without lesions continue to be able to work these longer hours. While we recognize that the cross-sectional nature of the study posed some inferential limitations, our results offer several potential intervention points for the prevention of these lesions. Specifically, we recommend the following until longitudinal studies can be conducted: increased monitoring of older elephants and the back region of all elephants, working less than 6 hours per day, and the avoidance of rice sacks as padding material in contact with skin.

  5. Peri-anal surgery under saddle block anaesthesia comparing three different doses of hyperbaric 0.75% bupivacaine

    International Nuclear Information System (INIS)

    Ali, L.; Alam, W.; Abbas, M.A.; Ali, U.

    2017-01-01

    To compare three doses of hyperbaric 0.75% bupivacaine and measuring time for home readiness after day care perianal surgery under saddle block anaesthesia. Study Design: Non randomized controlled trial. Place and Duration of Study: The study was conducted at the department of Anaesthesia, CMH Rawalpindi from Jun 2014 to Apr 2015. Material and Methods: In this study 90 patients who presented for perianal day care surgery, were divided in three equal groups. Group A received 7.5 mg, group B 6.0 mg and group C 4.5 mg of hyperbaric 0.75% bupivacaine. Intrathecal injection was given in L4-5 space by 25 G spinal needle in sitting position. Lithotomy position was made after five minutes. After surgery patients were monitored in recovery room. After fulfilling ambulatory and discharge criteria patients were allowed to go home with attendants. Time of intrathecal injection, assessment of above criteria and time of discharge were noted and analyzed. Results: Male patients were 85.6% and females were 14.4%. Mean time of surgery was 48 +- 10.59 min. Mean time of discharge in minutes for group A was 235.86 +- 49.38, for group B 217.7 +- 42.49 and for group C 205.76 +- 32. Time of discharge was significantly different between group A and group C (p=0.02). While it was not significantly different between group A and group B (p=0.29) and between group B and group C (p=0.819). Conclusion: Lower dose of hyperbaric bupivacaine can reduce the time for home readiness compared to higher dose. Time of discharge is mainly dependent on time to micturate after saddle block anaesthesia. (author)

  6. Hall Sensor Output Signal Fault-Detection & Safety Implementation Logic

    Directory of Open Access Journals (Sweden)

    Lee SangHun

    2016-01-01

    Full Text Available Recently BLDC motors have been popular in various industrial applications and electric mobility. Recently BLDC motors have been popular in various industrial applications and electric mobility. In most brushless direct current (BLDC motor drives, there are three hall sensors as a position reference. Low resolution hall effect sensor is popularly used to estimate the rotor position because of its good comprehensive performance such as low cost, high reliability and sufficient precision. Various possible faults may happen in a hall effect sensor. This paper presents a fault-tolerant operation method that allows the control of a BLDC motor with one faulty hall sensor and presents the hall sensor output fault-tolerant control strategy. The situations considered are when the output from a hall sensor stays continuously at low or high levels, or a short-time pulse appears on a hall sensor signal. For fault detection, identification of a faulty signal and generating a substitute signal, this method only needs the information from the hall sensors. There are a few research work on hall effect sensor failure of BLDC motor. The conventional fault diagnosis methods are signal analysis, model based analysis and knowledge based analysis. The proposed method is signal based analysis using a compensation signal for reconfiguration and therefore fault diagnosis can be fast. The proposed method is validated to execute the simulation using PSIM.

  7. The Hall module of an exact category with duality

    OpenAIRE

    Young, Matthew B.

    2012-01-01

    We construct from a finitary exact category with duality a module over its Hall algebra, called the Hall module, encoding the first order self-dual extension structure of the category. We study in detail Hall modules arising from the representation theory of a quiver with involution. In this case we show that the Hall module is naturally a module over the specialized reduced sigma-analogue of the quantum Kac-Moody algebra attached to the quiver. For finite type quivers, we explicitly determin...

  8. DESIGN OF SUBSOIL IMPROVEMENT BELOW HALL FLOORS

    Directory of Open Access Journals (Sweden)

    Peter Turček

    2017-10-01

    Full Text Available The construction of an industrial park is now being prepared near the town of Nitra. The investor fixed very strict conditions for the bearing capacity and, above all, the settlement of halls and their floors. The geological conditions at the construction site are difficult: there are soft clay soils with high compressibility and low bearing capacity. A detailed analysis of soil improvement was made. Stone columns were prepared to be fitted into an approximately 5 m thick layer of soft clay. The paper shows the main steps used in the design of the stone columns.

  9. Optically induced Hall effect in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Idrish Miah, M; Gray, E Mac A, E-mail: m.miah@griffith.edu.a [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)

    2009-03-01

    We describe an experiment which investigates the effect of a longitudinal electric field on the spin-polarized carriers generated by a circularly polarized light in semiconductors. Our experiment observes the effect as a Hall voltage resulting from nonequilibrium magnetization induced by the spin-carrier electrons accumulating at the transverse boundaries of the sample as a result of asymmetries in scattering for spin-up and spin-down electrons in the presence of spin-orbit interaction. It is found that the effect depends on the longitudinal electric field and doping density as well as on temperature. The results are presented by discussing the dominant spin relaxation mechanisms in semiconductors.

  10. Fractional quantization and the quantum hall effect

    International Nuclear Information System (INIS)

    Guerrero, J.; Calixto, M.; Aldaya, V.

    1998-01-01

    Quantization with constrains is considered in a group-theoretical framework, providing a precise characterization of the set of good operators, i.e., those preserving the constrained Hilbert space, in terms of the representation of the subgroup of constraints. This machinery is applied to the quantization of the torus as symplectic manifold, obtaining that fractional quantum numbers are permitted, provided that we allow for vector valued representations. The good operators turn out to be the Wilson loops and, for certain representations of the subgroup of constraints, the modular transformations. These results are applied to the Fractional Quantum Hall Effect, where interesting implications are derived

  11. Excitons in the Fractional Quantum Hall Effect

    Science.gov (United States)

    Laughlin, R. B.

    1984-09-01

    Quasiparticles of charge 1/m in the Fractional Quantum Hall Effect form excitons, which are collective excitations physically similar to the transverse magnetoplasma oscillations of a Wigner crystal. A variational exciton wavefunction which shows explicitly that the magnetic length is effectively longer for quasiparticles than for electrons is proposed. This wavefunction is used to estimate the dispersion relation of these excitons and the matrix elements to generate them optically out of the ground state. These quantities are then used to describe a type of nonlinear conductivity which may occur in these systems when they are relatively clean.

  12. The fractional quantum Hall effect goes organic

    International Nuclear Information System (INIS)

    Smet, Jurgen

    2000-01-01

    Physicists have been fascinated by the behaviour of two-dimensional electron gases for the past two decades. All of these experiments were performed on inorganic semiconductor devices, most of them based on gallium arsenide. Indeed, until recently it was thought that the subtle effects that arise due to electron-electron interactions in these devices required levels of purity that could not be achieved in other material systems. However, Hendrik Schoen, Christian Kloc and Bertram Batlogg of Bell Laboratories in the US have now observed the fractional quantum Hall effect - the most dramatic signature of electron-electron interactions - in two organic semiconductors. (U.K.)

  13. A Compton polarimeter for CEBAF Hall A

    Energy Technology Data Exchange (ETDEWEB)

    Bardin, G; Cavata, C; Frois, B; Juillard, M; Kerhoas, S; Languillat, J C; Legoff, J M; Mangeot, P; Martino, J; Platchkov, S; Rebourgeard, P; Vernin, P; Veyssiere, C; CEBAF Hall A Collaboration

    1994-09-01

    The physic program at CEBAF Hall A includes several experiments using 4 GeV polarized electron beam: parity violation in electron elastic scattering from proton and {sup 4}He, electric form factor of the proton by recoil polarization, neutron spin structure function at low Q{sup 2}. Some of these experiments will need beam polarization measurement and monitoring with an accuracy close to 4%, for beam currents ranging from 100 nA to 100 microA. A project of a Compton Polarimeter that will meet these requirements is presented. It will comprise four dipoles and a symmetric cavity consisting of two identical mirrors. 1 fig., 10 refs.

  14. Hall conductivity for two dimensional magnetic systems

    International Nuclear Information System (INIS)

    Desbois, J.; Ouvry, S.; Texier, C.

    1996-01-01

    A Kubo inspired formalism is proposed to compute the longitudinal and transverse dynamical conductivities of an electron in a plane (or a gas of electrons at zero temperature) coupled to the potential vector of an external local magnetic field, with the additional coupling of the spin degree of freedom of the electron to the local magnetic field (Pauli Hamiltonian). As an example, the homogeneous magnetic field Hall conductivity is rederived. The case of the vortex at the origin is worked out in detail. A perturbative analysis is proposed for the conductivity in the random magnetic impurity problem (Poissonian vortices in the plane). (author)

  15. Transit-time instability in Hall thrusters

    International Nuclear Information System (INIS)

    Barral, Serge; Makowski, Karol; Peradzynski, Zbigniew; Dudeck, Michel

    2005-01-01

    Longitudinal waves characterized by a phase velocity of the order of the velocity of ions have been recurrently observed in Hall thruster experiments and simulations. The origin of this so-called ion transit-time instability is investigated with a simple one-dimensional fluid model of a Hall thruster discharge in which cold ions are accelerated between two electrodes within a quasineutral plasma. A short-wave asymptotics applied to linearized equations shows that plasma perturbations in such a device consist of quasineutral ion acoustic waves superimposed on a background standing wave generated by discharge current oscillations. Under adequate circumstances and, in particular, at high ionization levels, acoustic waves are amplified as they propagate, inducing strong perturbation of the ion density and velocity. Responding to the subsequent perturbation of the column resistivity, the discharge current generates a standing wave, the reflection of which sustains the generation of acoustic waves at the inlet boundary. A calculation of the frequency and growth rate of this resonance mechanism for a supersonic ion flow is proposed, which illustrates the influence of the ionization degree on their onset and the approximate scaling of the frequency with the ion transit time. Consistent with experimental reports, the traveling wave can be observed on plasma density and velocity perturbations, while the plasma potential ostensibly oscillates in phase along the discharge

  16. Cylindrical Hall Thrusters with Permanent Magnets

    International Nuclear Information System (INIS)

    Raitses, Yevgeny; Merino, Enrique; Fisch, Nathaniel J.

    2010-01-01

    The use of permanent magnets instead of electromagnet coils for low power Hall thrusters can offer a significant reduction of both the total electric power consumption and the thruster mass. Two permanent magnet versions of the miniaturized cylindrical Hall thruster (CHT) of different overall dimensions were operated in the power range of 50W-300 W. The discharge and plasma plume measurements revealed that the CHT thrusters with permanent magnets and electromagnet coils operate rather differently. In particular, the angular ion current density distribution from the permanent magnet thrusters has an unusual halo shape, with a majority of high energy ions flowing at large angles with respect to the thruster centerline. Differences in the magnetic field topology outside the thruster channel and in the vicinity of the channel exit are likely responsible for the differences in the plume characteristics measured for the CHTs with electromagnets and permanent magnets. It is shown that the presence of the reversing-direction or cusp-type magnetic field configuration inside the thruster channel without a strong axial magnetic field outside the thruster channel does not lead to the halo plasma plume from the CHT.

  17. Bimetric Theory of Fractional Quantum Hall States

    Directory of Open Access Journals (Sweden)

    Andrey Gromov

    2017-11-01

    Full Text Available We present a bimetric low-energy effective theory of fractional quantum Hall (FQH states that describes the topological properties and a gapped collective excitation, known as the Girvin-Macdonald-Platzman (GMP mode. The theory consists of a topological Chern-Simons action, coupled to a symmetric rank-2 tensor, and an action à la bimetric gravity, describing the gapped dynamics of a spin-2 mode. The theory is formulated in curved ambient space and is spatially covariant, which allows us to restrict the form of the effective action and the values of phenomenological coefficients. Using bimetric theory, we calculate the projected static structure factor up to the k^{6} order in the momentum expansion. To provide further support for the theory, we derive the long-wave limit of the GMP algebra, the dispersion relation of the GMP mode, and the Hall viscosity of FQH states. The particle-hole (PH transformation of the theory takes a very simple form, making the duality between FQH states and their PH conjugates manifest. We also comment on the possible applications to fractional Chern insulators, where closely related structures arise. It is shown that the familiar FQH observables acquire a curious geometric interpretation within the bimetric formalism.

  18. Hypernuclear Spectroscopy at JLab Hall C

    International Nuclear Information System (INIS)

    Hashimoto, Osamu; Chiba, Atsushi; Doi, Daisuke; Fujii, Yu; Toshiyuki, Gogami; Kanda, Hiroki; Kaneta, M.; Kawama, Daisuke; Maeda, Kazushige; Maruta, Tomofumi; Matsumura, Akihiko; Nagao, Sho; Nakamura, Satoshi; Shichijo, Ayako; Tamura, Hirokazu; Taniya, Naotaka; Yamamoto, Taku; Yokota, Kosuke; Kato, S.; Sato, Yoshinori; Takahashi, Toshiyuki; Noumi, Hiroyuki; Motoba, T.; Hiyama, E.; Albayrak, Ibrahim; Ates, Ozgur; Chen, Chunhua; Christy, Michael; Keppel, Cynthia; Kohl, Karl; Li, Ya; Liyanage, Anusha Habarakada; Tang, Liguang; Walton, T.; Ye, Zhihong; Yuan, Lulin; Zhu, Lingyan; Baturin, Pavlo; Boeglin, Werner; Dhamija, Seema; Markowitz, Pete; Raue, Brian; Reinhold, Joerg; Hungerford, Ed; Ent, Rolf; Fenker, Howard; Gaskell, David; Horn, Tanja; Jones, Mark; Smith, Gregory; Vulcan, William; Wood, Stephen; Johnston, C.; Simicevic, Neven; Wells, Stephen; Samanta, Chhanda; Hu, Bitao; Shen, Ji; Wang, W.; Zhang, Xiaozhuo; Zhang, Yi; Feng, Jing; Fu, Y.; Zhou, Jian; Zhou, S.; Jiang, Yi; Lu, H.; Yan, Xinhu; Ye, Yunxiu; Gan, Liping; Ahmidouch, Abdellah; Danagoulian, Samuel; Gasparian, Ashot; Elaasar, Mostafa; Wesselmann, Frank; Asaturyan, Arshak; Margaryan, Amur; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Tadevosyan, Vardan; Androic, Darko; Furic, Miroslav; Petkovic, Tomislav; Seva, Tomislav; Niculescu, Gabriel; Niculescu, Maria-Ioana; Rodriguez, Victor; Cisbani, Evaristo; Cusanno, Francesco; Garibaldi, Franco; Urciuoli, Guido; De Leo, Raffaele; Maronne, S.; Achenbach, Carsten; Pochodzalla, J.

    2010-01-01

    Since the 1st generation experiment, E89-009, which was successfully carried out as a pilot experiment of (e,e(prime)K + ) hypernuclear spectroscopy at JLab Hall C in 2000, precision hypernuclear spectroscopy by the (e,e(prime)K + ) reactions made considerable progress. It has evolved to the 2nd generation experiment, E01-011, in which a newly constructed high resolution kaon spectrometer (HKS) was installed and the 'Tilt method' was adopted in order to suppress large electromagnetic background and to run with high luminosity. Preliminary high-resolution spectra of 7 ΛHe and 28 ΛAl together with that of 12 ΛB that achieved resolution better than 500 keV(FWHM) were obtained. The third generation experiment, E05-115, has completed data taking with an experimental setup combining a new splitter magnet, high resolution electron spectrometer (HES) and the HKS used in the 2nd generation experiment. The data were accumulated with targets of 7 Li, 9 Be, 10 B, 12 C and 52 Cr as well as with those of CH 2 and H 2 O for calibration. The analysis is under way with particular emphasis of determining precision absolute hypernuclear masses. In this article, hypernuclear spectroscopy program in the wide mass range at JLab Hall C that has undergone three generation is described.

  19. Bimetric Theory of Fractional Quantum Hall States

    Science.gov (United States)

    Gromov, Andrey; Son, Dam Thanh

    2017-10-01

    We present a bimetric low-energy effective theory of fractional quantum Hall (FQH) states that describes the topological properties and a gapped collective excitation, known as the Girvin-Macdonald-Platzman (GMP) mode. The theory consists of a topological Chern-Simons action, coupled to a symmetric rank-2 tensor, and an action à la bimetric gravity, describing the gapped dynamics of a spin-2 mode. The theory is formulated in curved ambient space and is spatially covariant, which allows us to restrict the form of the effective action and the values of phenomenological coefficients. Using bimetric theory, we calculate the projected static structure factor up to the k6 order in the momentum expansion. To provide further support for the theory, we derive the long-wave limit of the GMP algebra, the dispersion relation of the GMP mode, and the Hall viscosity of FQH states. The particle-hole (PH) transformation of the theory takes a very simple form, making the duality between FQH states and their PH conjugates manifest. We also comment on the possible applications to fractional Chern insulators, where closely related structures arise. It is shown that the familiar FQH observables acquire a curious geometric interpretation within the bimetric formalism.

  20. Repurposing the Caltech Robinson Hall Coelostat

    Science.gov (United States)

    Treffers, Richard R.; Loisos, G.; Ubbelohde, M.; Douglas, S.; Martinez, M.

    2013-01-01

    We describe the repurposing of the historic coelostat atop Caltech’s Robinson Hall for building lighting, public education and scientific research. The coelostat was originally part of George Ellery Hale’s vision of the Astrophysical Laboratory on the Caltech campus in 1932. The coelostat, designed by Russell Porter, has a 36 inch diameter primary mirror a 30 inch diameter secondary mirror and provides a 24 inch un-vignetted beam of sunlight into the building. Although constructed in the 1930s, due to wartime pressures and other projects, it was used only briefly in the 1970s and never fully realized. Recently Robinson Hall has been fully renovated to house the Ronald and Maxine Linde Center for Global Environmental Science. The coelostat operation was modernized replacing the old motors and automating all the motions. Each morning, if the weather cooperates, the dome slit opens, the mirrors configured and sunlight pours into the building. The beam of sunlight is divided into three parts. One part goes into a refracting telescope which projects a ten inch diameter of the sun onto a ground glass screen visible to the public. A second fraction is distributed to fiber optic fixtures that illuminate some of the basement rooms. The final fraction goes into two laboratories where it is used in experiments monitoring trace constituents of our atmosphere and for solar catalysis experiments. The instrument as originally conceived required at least two human operators. Now it is fully automatic and doing real science

  1. Undulator Hall Air Temperature Fault Scenarios

    International Nuclear Information System (INIS)

    Sevilla, J.

    2010-01-01

    Recent experience indicates that the LCLS undulator segments must not, at any time following tuning, be allowed to change temperature by more than about ±2.5 C or the magnetic center will irreversibly shift outside of acceptable tolerances. This vulnerability raises a concern that under fault conditions the ambient temperature in the Undulator Hall might go outside of the safe range and potentially could require removal and retuning of all the segments. In this note we estimate changes that can be expected in the Undulator Hall air temperature for three fault scenarios: (1) System-wide power failure; (2) Heating Ventilation and Air Conditioning (HVAC) system shutdown; and (3) HVAC system temperature regulation fault. We find that for either a system-wide power failure or an HVAC system shutdown (with the technical equipment left on), the short-term temperature changes of the air would be modest due to the ability of the walls and floor to act as a heat ballast. No action would be needed to protect the undulator system in the event of a system-wide power failure. Some action to adjust the heat balance, in the case of the HVAC power failure with the equipment left on, might be desirable but is not required. On the other hand, a temperature regulation failure of the HVAC system can quickly cause large excursions in air temperature and prompt action would be required to avoid damage to the undulator system.

  2. Test Review: Beaver, J. M., & Carter, M. A. (2006). "The Developmental Reading Assessment--Second Edition" (DRA2). Upper Saddle River, NJ--Pearson

    Science.gov (United States)

    McCarty, Allison M.; Christ, Theodore J.

    2010-01-01

    This article reviews the "Developmental Reading Assessment--Second Edition" (DRA2), a teacher-administered assessment that identifies students' instructional level, along with their strengths and weaknesses in reading. Once teachers calculate and interpret scores, the data can purportedly be used to inform, and possibly individualize,…

  3. Mary E. Hall: Dawn of the Professional School Librarian

    Science.gov (United States)

    Alto, Teresa

    2012-01-01

    A century ago, a woman named Mary E. Hall convinced school leaders of the need for the professional school librarian--a librarian who cultivated a love of reading, academic achievement, and independent learning skills. After graduating from New York City's Pratt Institute Library School in 1895, Hall developed her vision for the high school…

  4. What is the Hallé? | Smith | Philosophical Papers

    African Journals Online (AJOL)

    The bulk of the paper examines the difficulty of reconciling the view that the Hallé is several individuals with two prima facie plausible theses about the manner of its persistence through time. The paper is structured around some remarks made by Peter Simons about groups, and the Hallé in particular, in his Parts.

  5. Spin hall effect associated with SU(2) gauge field

    Science.gov (United States)

    Tao, Y.

    2010-01-01

    In this paper, we focus on the connection between spin Hall effect and spin force. Here we investigate that the spin force due to spin-orbit coupling, which, in two-dimensional system, is equivalent to forces of Hirsch and Chudnovsky besides constant factors 3 and frac{3}{2} respectively, is a part of classic Anandan force, and that the spin Hall effect is an anomalous Hall effect. Furthermore, we develop the method of AC phase to derive the expression for the spin force, and note that the most basic spin Hall effect indeed originate from the AC phase and is therefore an intrinsic quantum mechanical property of spin. This method differs from approach of Berry phase in the study of anomalous Hall effect , which is the intrinsic property of the perfect crystal. On the other hand, we use an elegant skill to show that the Chudnovsky-Drude model is reasonable. Here we have improved the theoretical values of spin Hall conductivity of Chudnovsky. Compared to the theoretical values of spin Hall conductivity in the Chudnovsky-Drude model, ours are in better agreement with experimentation. Finally, we discuss the relation between spin Hall effect and fractional statistics.

  6. Energy spectrum, dissipation, and spatial structures in reduced Hall magnetohydrodynamic

    Energy Technology Data Exchange (ETDEWEB)

    Martin, L. N.; Dmitruk, P. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Gomez, D. O. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Instituto de Astronomia y Fisica del Espacio, CONICET, Buenos Aires (Argentina)

    2012-05-15

    We analyze the effect of the Hall term in the magnetohydrodynamic turbulence under a strong externally supported magnetic field, seeing how this changes the energy cascade, the characteristic scales of the flow, and the dynamics of global magnitudes, with particular interest in the dissipation. Numerical simulations of freely evolving three-dimensional reduced magnetohydrodynamics are performed, for different values of the Hall parameter (the ratio of the ion skin depth to the macroscopic scale of the turbulence) controlling the impact of the Hall term. The Hall effect modifies the transfer of energy across scales, slowing down the transfer of energy from the large scales up to the Hall scale (ion skin depth) and carrying faster the energy from the Hall scale to smaller scales. The final outcome is an effective shift of the dissipation scale to larger scales but also a development of smaller scales. Current sheets (fundamental structures for energy dissipation) are affected in two ways by increasing the Hall effect, with a widening but at the same time generating an internal structure within them. In the case where the Hall term is sufficiently intense, the current sheet is fully delocalized. The effect appears to reduce impulsive effects in the flow, making it less intermittent.

  7. Quantifying Spin Hall Angles from Spin Pumping : Experiments and Theory

    NARCIS (Netherlands)

    Mosendz, O.; Pearson, J.E.; Fradin, F.Y.; Bauer, G.E.W.; Bader, S.D.; Hoffmann, A.

    2010-01-01

    Spin Hall effects intermix spin and charge currents even in nonmagnetic materials and, therefore, ultimately may allow the use of spin transport without the need for ferromagnets. We show how spin Hall effects can be quantified by integrating Ni80Fe20|normal metal (N) bilayers into a coplanar

  8. Stuart Hall on Racism and the Importance of Diasporic Thinking

    Science.gov (United States)

    Rizvi, Fazal

    2015-01-01

    In this article, I want to show how my initial encounter with the work of Stuart Hall was grounded in my reading of the later philosophy of Ludwig Wittgenstein, and was shaped by my interest in understanding the nature of racism across the three countries in which I had lived. Over the years, Hall's various writings have helped me to make sense of…

  9. Theory of the quantum hall effects in lattice systems

    International Nuclear Information System (INIS)

    Kliros, G.S.

    1990-06-01

    The Fractional Quantum Hall Effect is identified as an Integral Quantum Hall Effect of electrons on a lattice with an even number of statistical flux quanta. A variational wavefunction in terms of the Hofstadter lattice eigenstates is proposed. (author). 21 refs

  10. A Residential Paradox?: Residence Hall Attributes and College Student Outcomes

    Science.gov (United States)

    Bronkema, Ryan; Bowman, Nicholas A.

    2017-01-01

    The researchers of this brief observed that few environments have the potential to shape the outcomes of college students as much as residence halls. As a result, residence halls have the capacity to foster a strong sense of community as well as other important outcomes such as college satisfaction and academic achievement. However, given the high…

  11. Bulk Versus Edge in the Quantum Hall Effect

    OpenAIRE

    Kao, Y. -C.; Lee, D. -H.

    1996-01-01

    The manifestation of the bulk quantum Hall effect on edge is the chiral anomaly. The chiral anomaly {\\it is} the underlying principle of the ``edge approach'' of quantum Hall effect. In that approach, $\\sxy$ should not be taken as the conductance derived from the space-local current-current correlation function of the pure one-dimensional edge problem.

  12. Critical current in the Integral Quantum Hall Effect

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.

    1985-11-01

    A multiparticle theory of the Integral Quantum Hall Effect (IQHE) was constructed operating with pairs wave function as an order parameter. The IQHE is described with bosonic macroscopic states while the fractional QHE with fermionic ones. The calculation of the critical current and Hall conductivity temperature dependence is presented. (author)

  13. Useful Pedagogical Applications of the Classical Hall Effect

    Science.gov (United States)

    Houari, Ahmed

    2007-01-01

    One of the most known phenomena in physics is the Hall effect. This is mainly due to its simplicity and to the wide range of its theoretical and practical applications. To complete the pedagogical utility of the Hall effect in physics teaching, I will apply it here to determine the Faraday constant as a fundamental physical number and the number…

  14. A Novel Hall Effect Sensor Using Elaborate Offset Cancellation Method

    Directory of Open Access Journals (Sweden)

    Vlassis N. Petoussis

    2009-01-01

    Full Text Available The Hall effect is caused by a traverse force that is formed in the electrons or holes of metal element or semiconductor when are polarized by current source and simultaneously all the system it is found vertical in external magnetic field. Result is finally the production of difference of potential (Hall voltage in address vertical in that of current and magnetic field directions. In the present work is presented a new Hall sensor exploiting the former operation. In combination with his pioneering form and using dynamic spinning current technique with an elaborate sequence, it leads to satisfactory results of produced Hall voltage with small noise in a presence of external magnetic field. Anyone can see both the spinning current and anti-Hall technique in the same sensor simultaneously.

  15. Migrants and Their Experiences of Time: Edward T. Hall Revisited

    Directory of Open Access Journals (Sweden)

    Elisabeth Schilling

    2009-01-01

    Full Text Available In this paper we reassess the scientific heritage of Edward T. HALL and his contribution to the area of intercultural communication. The key objectives of our study are to demonstrate the applicability of HALL's theory of culture to empirical research and to establish its compatibility with other methods. Specifically, we propose that Alfred SCHÜTZ's phenomenology of sociality be taken as an extension to HALL. The connection between HALL and SCHÜTZ is made possible by the mutual emphases on the temporal dimension of culture and the temporal aspects of migration. With these foci we analyze six narratives by two groups of migrants: German and Russian. By combining HALL's theory of the cultural time with SCHÜTZ's phenomenological perspective on time and the Other and then applying them to empirical data, we show the terms in which different cultures experience time. URN: urn:nbn:de:0114-fqs0901357

  16. Unconventional quantum Hall effect in Floquet topological insulators

    KAUST Repository

    Tahir, M.

    2016-07-27

    We study an unconventional quantum Hall effect for the surface states of ultrathin Floquet topological insulators in a perpendicular magnetic field. The resulting band structure is modified by photon dressing and the topological property is governed by the low-energy dynamics of a single surface. An exchange of symmetric and antisymmetric surface states occurs by reversing the lights polarization. We find a novel quantum Hall state in which the zeroth Landau level undergoes a phase transition from a trivial insulator state, with Hall conductivity αyx = 0 at zero Fermi energy, to a Hall insulator state with αyx = e2/2h. These findings open new possibilities for experimentally realizing nontrivial quantum states and unusual quantum Hall plateaus at (±1/2,±3/2,±5/2, ...)e2/h. © 2016 IOP Publishing Ltd Printed in the UK.

  17. Magnetic Measurements of the Background Field in the Undulator Hall

    International Nuclear Information System (INIS)

    Fisher, Andrew

    2010-01-01

    The steel present in the construction of the undulator hall facility has the potential for changing the ambient fields present in the undulator hall. This note describes a measurement done to make a comparison between the fields in the hall and in the Magnetic Measurement Facility. In order for the undulators to have the proper tuning, the background magnetic field in the Undulator Hall should agree with the background field in the Magnetic Measurements Facility within .5 gauss. In order to verify that this was the case measurements were taken along the length of the undulator hall, and the point measurements were compared to the mean field which was measured on the MMF test bench.

  18. Unconventional quantum Hall effect in Floquet topological insulators

    KAUST Repository

    Tahir, M.; Vasilopoulos, P.; Schwingenschlö gl, Udo

    2016-01-01

    We study an unconventional quantum Hall effect for the surface states of ultrathin Floquet topological insulators in a perpendicular magnetic field. The resulting band structure is modified by photon dressing and the topological property is governed by the low-energy dynamics of a single surface. An exchange of symmetric and antisymmetric surface states occurs by reversing the lights polarization. We find a novel quantum Hall state in which the zeroth Landau level undergoes a phase transition from a trivial insulator state, with Hall conductivity αyx = 0 at zero Fermi energy, to a Hall insulator state with αyx = e2/2h. These findings open new possibilities for experimentally realizing nontrivial quantum states and unusual quantum Hall plateaus at (±1/2,±3/2,±5/2, ...)e2/h. © 2016 IOP Publishing Ltd Printed in the UK.

  19. Planar Hall Effect Sensors for Biodetection

    DEFF Research Database (Denmark)

    Rizzi, Giovanni

    . In the second geometry (dPHEB) half of the sensor is used as a local negative reference to subtract the background signal from magnetic beads in suspension. In all applications below, the magnetic beads are magnetised using the magnetic field due to the bias current passed through the sensor, i.e., no external...... as labels and planar Hall effect bridge (PHEB) magnetic field sensor as readout for the beads. The choice of magnetic beads as label is motivated by the lack of virtually any magnetic background from biological samples. Moreover, magnetic beads can be manipulated via an external magnetic field...... hybridisation in real-time, in a background of suspended magnetic beads. This characteristic is employed in single nucleotide polymorphism (SNP) genotyping, where the denaturation of DNA is monitored in real-time upon washing with a stringency buffer. The sensor setup includes temperature control and a fluidic...

  20. Numerical investigation of a Hall thruster plasma

    International Nuclear Information System (INIS)

    Roy, Subrata; Pandey, B.P.

    2002-01-01

    The dynamics of the Hall thruster is investigated numerically in the framework of a one-dimensional, multifluid macroscopic description of a partially ionized xenon plasma using finite element formulation. The model includes neutral dynamics, inelastic processes, and plasma-wall interaction. Owing to disparate temporal scales, ions and neutrals have been described by set of time-dependent equations, while electrons are considered in steady state. Based on the experimental observations, a third order polynomial in electron temperature is used to calculate ionization rate. The results show that in the acceleration channel the increase in the ion number density is related to the decrease in the neutral number density. The electron and ion velocity profiles are consistent with the imposed electric field. The electron temperature remains uniform for nearly two-thirds of the channel; then sharply increases to a peak before dropping slightly at the exit. This is consistent with the predicted electron gyration velocity distribution

  1. Quantum Hall effect on Riemann surfaces

    Science.gov (United States)

    Tejero Prieto, Carlos

    2009-06-01

    We study the family of Landau Hamiltonians compatible with a magnetic field on a Riemann surface S by means of Fourier-Mukai and Nahm transforms. Starting from the geometric formulation of adiabatic charge transport on Riemann surfaces, we prove that Hall conductivity is proportional to the intersection product on the first homology group of S and therefore it is quantized. Finally, by using the theory of determinant bundles developed by Bismut, Gillet and Soul, we compute the adiabatic curvature of the spectral bundles defined by the holomorphic Landau levels. We prove that it is given by the polarization of the jacobian variety of the Riemann surface, plus a term depending on the relative analytic torsion.

  2. Quantum Hall effect on Riemann surfaces

    International Nuclear Information System (INIS)

    Tejero Prieto, Carlos

    2009-01-01

    We study the family of Landau Hamiltonians compatible with a magnetic field on a Riemann surface S by means of Fourier-Mukai and Nahm transforms. Starting from the geometric formulation of adiabatic charge transport on Riemann surfaces, we prove that Hall conductivity is proportional to the intersection product on the first homology group of S and therefore it is quantized. Finally, by using the theory of determinant bundles developed by Bismut, Gillet and Soul, we compute the adiabatic curvature of the spectral bundles defined by the holomorphic Landau levels. We prove that it is given by the polarization of the jacobian variety of the Riemann surface, plus a term depending on the relative analytic torsion.

  3. Frequency spectrum of Calder Hall reactor noise

    International Nuclear Information System (INIS)

    Cummins, J.D.

    1960-01-01

    The frequency spectrum of the noise power of Calder Hall reactor No. 1 has been obtained by analysing a tape recording of the backed off power. The root mean square noise power due to all frequencies above 0.001 cycles per second was found to be 0.13%. The noise power for this reactor, is due mainly to modulations of the power level by reactivity variations caused in turn by gas temperature changes. These gas temperature changes are caused by a Cyclic variation in the feedwater regulator to the heat exchanger. The apparatus and method used to determine the noise power are described in this memorandum. It is shown that for frequencies in the range 0.001 to 0.030 cycles per second the noise spectrum falls at 60 decibels per decade of frequency. (author)

  4. OPTICS. Quantum spin Hall effect of light.

    Science.gov (United States)

    Bliokh, Konstantin Y; Smirnova, Daria; Nori, Franco

    2015-06-26

    Maxwell's equations, formulated 150 years ago, ultimately describe properties of light, from classical electromagnetism to quantum and relativistic aspects. The latter ones result in remarkable geometric and topological phenomena related to the spin-1 massless nature of photons. By analyzing fundamental spin properties of Maxwell waves, we show that free-space light exhibits an intrinsic quantum spin Hall effect—surface modes with strong spin-momentum locking. These modes are evanescent waves that form, for example, surface plasmon-polaritons at vacuum-metal interfaces. Our findings illuminate the unusual transverse spin in evanescent waves and explain recent experiments that have demonstrated the transverse spin-direction locking in the excitation of surface optical modes. This deepens our understanding of Maxwell's theory, reveals analogies with topological insulators for electrons, and offers applications for robust spin-directional optical interfaces. Copyright © 2015, American Association for the Advancement of Science.

  5. Determination of the Hall Thruster Operating Regimes

    International Nuclear Information System (INIS)

    L. Dorf; V. Semenov; Y. Raitses; N.J. Fisch

    2002-04-01

    A quasi one-dimensional (1-D) steady-state model of the Hall thruster is presented. For the same discharge voltage two operating regimes are possible -- with and without the anode sheath. For given mass flow rate, magnetic field profile and discharge voltage a unique solution can be constructed, assuming that the thruster operates in one of the regimes. However, we show that for a given temperature profile the applied discharge voltage uniquely determines the operating regime: for discharge voltages greater than a certain value, the sheath disappears. That result is obtained over a wide range of incoming neutral velocities, channel lengths and widths, and cathode plane locations. It is also shown that a good correlation between the quasi 1-D model and experimental results can be achieved by selecting an appropriate electron mobility and temperature profile

  6. Chaotic waves in Hall thruster plasma

    International Nuclear Information System (INIS)

    Peradzynski, Zbigniew; Barral, S.; Kurzyna, J.; Makowski, K.; Dudeck, M.

    2006-01-01

    The set of hyperbolic equations of the fluid model describing the acceleration of plasma in a Hall thruster is analyzed. The characteristic feature of the flow is the existence of a trapped characteristic; i.e. there exists a characteristic line, which never intersects the boundary of the flow region in the thruster. To study the propagation of short wave perturbations, the approach of geometrical optics (like WKB) can be applied. This can be done in a linear as well as in a nonlinear version. The nonlinear version describes the waves of small but finite amplitude. As a result of such an approach one obtains so called transport equation, which are governing the wave amplitude. Due to the existence of trapped characteristics this transport equation appears to have chaotic (turbulent) solutions in both, linear and nonlinear versions

  7. Spin Hall magnetoresistance at high temperatures

    International Nuclear Information System (INIS)

    Uchida, Ken-ichi; Qiu, Zhiyong; Kikkawa, Takashi; Iguchi, Ryo; Saitoh, Eiji

    2015-01-01

    The temperature dependence of spin Hall magnetoresistance (SMR) in Pt/Y 3 Fe 5 O 12 (YIG) bilayer films has been investigated in a high temperature range from room temperature to near the Curie temperature of YIG. The experimental results show that the magnitude of the magnetoresistance ratio induced by the SMR monotonically decreases with increasing the temperature and almost disappears near the Curie temperature. We found that, near the Curie temperature, the temperature dependence of the SMR in the Pt/YIG film is steeper than that of a magnetization curve of the YIG; the critical exponent of the magnetoresistance ratio is estimated to be 0.9. This critical behavior of the SMR is attributed mainly to the temperature dependence of the spin-mixing conductance at the Pt/YIG interface

  8. Concept of Operating Indoor Skiing Halls with

    DEFF Research Database (Denmark)

    Paul, Joachim

    2003-01-01

    Indoor skiing halls are conventionally operated at low temperatures and with either crushed ice as snow substitute or snow made from freezing water in cold air. Both systems have a high energy demand for air cooling, floor freezing and consequently snow harvest. At the same time the snow at the top...... floor cooling/freezing and insulation become obsolete, significant savings in piping and building costs can be achieved. Due to the much higher evaporating temperature for the refrigeration system, the energy demand is kept low. Since the same equipment is used for both snowmaking and air cooling......, the running time of the equipment is high, resulting in a better economy. Using Binary Snow, with its unique qualities such as fluffy, crisp, white and ¿ since made daily ¿ "fresh and hygienic", offers great advantages in operating costs, investment costs and quality....

  9. Geometrical Description of fractional quantum Hall quasiparticles

    Science.gov (United States)

    Park, Yeje; Yang, Bo; Haldane, F. D. M.

    2012-02-01

    We examine a description of fractional quantum Hall quasiparticles and quasiholes suggested by a recent geometrical approach (F. D. M. Haldane, Phys. Rev. Lett. 108, 116801 (2011)) to FQH systems, where the local excess electric charge density in the incompressible state is given by a topologically-quantized ``guiding-center spin'' times the Gaussian curvature of a ``guiding-center metric tensor'' that characterizes the local shape of the correlation hole around electrons in the fluid. We use a phenomenological energy function with two ingredients: the shear distortion energy of area-preserving distortions of the fluid, and a local (short-range) approximation to the Coulomb energy of the fluctuation of charge density associated with the Gaussian curvature. Quasiparticles and quasiholes of the 1/3 Laughlin state are modeled as ``punctures'' in the incompressible fluid which then relax by geometric distortion which generates Gaussian curvature, giving rise to the charge-density profile around the topological excitation.

  10. Cathode Effects in Cylindrical Hall Thrusters

    Energy Technology Data Exchange (ETDEWEB)

    Granstedt, E.M.; Raitses, Y.; Fisch, N. J.

    2008-09-12

    Stable operation of a cylindrical Hall thruster (CHT) has been achieved using a hot wire cathode, which functions as a controllable electron emission source. It is shown that as the electron emission from the cathode increases with wire heating, the discharge current increases, the plasma plume angle reduces, and the ion energy distribution function shifts toward higher energies. The observed effect of cathode electron emission on thruster parameters extends and clarifies performance improvements previously obtained for the overrun discharge current regime of the same type of thruster, but using a hollow cathode-neutralizer. Once thruster discharge current saturates with wire heating, further filament heating does not affect other discharge parameters. The saturated values of thruster discharge parameters can be further enhanced by optimal placement of the cathode wire with respect to the magnetic field.

  11. On-Chip Microwave Quantum Hall Circulator

    Directory of Open Access Journals (Sweden)

    A. C. Mahoney

    2017-01-01

    Full Text Available Circulators are nonreciprocal circuit elements that are integral to technologies including radar systems, microwave communication transceivers, and the readout of quantum information devices. Their nonreciprocity arises from the interference of microwaves over the centimeter scale of the signal wavelength, in the presence of bulky magnetic media that breaks time-reversal symmetry. Here, we realize a completely passive on-chip microwave circulator with size 1/1000th the wavelength by exploiting the chiral, “slow-light” response of a two-dimensional electron gas in the quantum Hall regime. For an integrated GaAs device with 330  μm diameter and about 1-GHz center frequency, a nonreciprocity of 25 dB is observed over a 50-MHz bandwidth. Furthermore, the nonreciprocity can be dynamically tuned by varying the voltage at the port, an aspect that may enable reconfigurable passive routing of microwave signals on chip.

  12. Mesoscopic spin Hall effect in semiconductor nanostructures

    Science.gov (United States)

    Zarbo, Liviu

    The spin Hall effect (SHE) is a name given to a collection of diverse phenomena which share two principal features: (i) longitudinal electric current flowing through a paramagnetic semiconductor or metallic sample leads to transverse spin current and spin accumulation of opposite sign at opposing lateral edges; (ii) SHE does not require externally applied magnetic field or magnetic ordering in the equilibrium state of the sample, instead it relies on the presence of spin-orbit (SO) couplings within the sample. This thesis elaborates on a new type of phenomenon within the SHE family, predicted in our recent studies [Phys. Rev. B 72, 075361 (2005); Phys. Rev. Lett. 95, 046601 (2005); Phys. Rev. B 72, 075335 (2005); Phys. Rev. B 73 , 075303 (2006); and Europhys. Lett. 77, 47004 (2007)], where pure spin current flows through the transverse electrodes attached to a clean finitesize two-dimensional electron gas (2DEG) due to unpolarized charge current injected through its longitudinal leads. If transverse leads are removed, the effect manifests as nonequilibrium spin Hall accumulation at the lateral edges of 2DEG wires. The SO coupling driving this SHE effect is of the Rashba type, which arises due to structural inversion asymmetry of semiconductor heterostructure hosting the 2DEG. We term the effect "mesoscopic" because the spin Hall currents and accumulations reach optimal value in samples of the size of the spin precession length---the distance over which the spin of an electron precesses by an angle pi. In strongly SO-coupled structures this scale is of the order of ˜100 nm, and, therefore, mesoscopic in the sense of being much larger than the characteristic microscopic scales (such as the Fermi wavelength, screening length, or the mean free path in disordered systems), but still much smaller than the macroscopic ones. Although the first theoretical proposal for SHE, driven by asymmetry in SO-dependent scattering of spin-up and spin-down electrons off impurities

  13. 50 KW Class Krypton Hall Thruster Performance

    Science.gov (United States)

    Jacobson, David T.; Manzella, David H.

    2003-01-01

    The performance of a 50-kilowatt-class Hall thruster designed for operation on xenon propellant was measured using kryton propellant. The thruster was operated at discharge power levels ranging from 6.4 to 72.5 kilowatts. The device produced thrust ranging from 0.3 to 2.5 newtons. The thruster was operated at discharge voltages between 250 and 1000 volts. At the highest anode mass flow rate and discharge voltage and assuming a 100 percent singly charged condition, the discharge specific impulse approached the theoretical value. Discharge specific impulse of 4500 seconds was demonstrated at a discharge voltage of 1000 volts. The peak discharge efficiency was 64 percent at 650 volts.

  14. Magnon Hall effect on the Lieb lattice.

    Science.gov (United States)

    Cao, Xiaodong; Chen, Kai; He, Dahai

    2015-04-29

    Ferromagnetic insulators without inversion symmetry may show magnon Hall effect (MHE) in the presence of a temperature gradient due to the existence of Dzyaloshinskii-Moriya interaction (DMI). In this theoretical study, we investigate MHE on a lattice with inversion symmetry, namely the Lieb lattice, where the DMI is introduced by adding an external electric field. We show the nontrivial topology of this model by examining the existence of edge states and computing the topological phase diagram characterized by the Chern numbers of different bands. Together with the topological phase diagram, we can further determine the sign and magnitude of the transverse thermal conductivity. The impact of the flat band possessed by this model on the thermal conductivity is discussed by computing the Berry curvature analytically.

  15. Photonic spin Hall effect at metasurfaces.

    Science.gov (United States)

    Yin, Xiaobo; Ye, Ziliang; Rho, Junsuk; Wang, Yuan; Zhang, Xiang

    2013-03-22

    The spin Hall effect (SHE) of light is very weak because of the extremely small photon momentum and spin-orbit interaction. Here, we report a strong photonic SHE resulting in a measured large splitting of polarized light at metasurfaces. The rapidly varying phase discontinuities along a metasurface, breaking the axial symmetry of the system, enable the direct observation of large transverse motion of circularly polarized light, even at normal incidence. The strong spin-orbit interaction deviates the polarized light from the trajectory prescribed by the ordinary Fermat principle. Such a strong and broadband photonic SHE may provide a route for exploiting the spin and orbit angular momentum of light for information processing and communication.

  16. Residencia hall del Obispado, en Gescher, Alemania

    Directory of Open Access Journals (Sweden)

    Deilmann, Harald

    1969-02-01

    Full Text Available This Hall has four lecture rooms, each with a capacity for twenty students. They all face north, have lateral and cenithal illumination and cross ventilation. The workshop training halls face south, and there is a gymnasium. Each classroom is also connected with a protected open air space, so that in suitable weather, teaching can be practised out of doors. As the school is devoted to mentally retarded boys and youths, over 2 m2 of floor area has been allowed for each student in the classrooms, since it was estimated that many students would be of the nervous type and would need more room to work freely. Most of the construction is made with unfaced brick and concrete, which are long lasting materials, requiring little maintenance.Comprende cuatro clases propiamente dichas, con una capacidad total de 80 alumnos, a razón de 20 por cada clase, y orientadas al norte, con iluminación cenital y lateral y ventilación cruzada. Los locales donde se imparten las enseñanzas de taller tienen orientación sur. Se ha previsto, además, un gimnasio. Cada clase dispone de un recinto protegido para que, cuando las condiciones atmosféricas lo permitan, se pueda desarrollar en él la enseñanza al aire libre. Como la escuela está destinada a niños y adolescentes retrasados mentales, se partió de un espacio superior a los 2 m2 por alumno, pensando en que parte de ellos iban a ser niños nerviosos y, como consecuencia, la necesidad que tendrían de amplitud suficiente para desenvolverse adecuadamente. La construcción se ha desarrollado, en general, a base de fábrica de ladrillo a cara vista y hormigón visto, materiales de gran duración y prácticamente exentos de entretenimiento.

  17. Nonadiabatic effects in the Quantum Hall regime

    International Nuclear Information System (INIS)

    Page, D.A.; Brown, E.

    1993-01-01

    The authors consider the effect of a finite electric field on the states of a Bloch electron in two dimensions, with a uniform magnetic field present. They make use of the concept of electric time translation symmetry and treat the electric and magnetic fields symmetrically in a time dependent formalism. In addition to a wave vector k, the states are characterized by a frequency specifying the behavior under electric time translations. An effective Hamiltonian is employed to obtain the splitting of an isolated Bloch band into open-quotes frequencyclose quotes subbands. The time-averaged velocity and energy of the states are expressed in terms of the frequency dispersion. The relationship to the Stark ladder eigenstates in a scalar potential representation of the electric field is examined. This is seen to justify the use of the averaged energy in determining occupation of the states. In the weak electric field (adiabatic) limit, an expression is recovered for the quantized Hall conductivity of a magnetic subband as a topological invariant. A numerical procedure is outlined and results obtained over a range of electric field strengths. A transition between strong and weak field regimes is seen, with level repulsions between the frequencies playing an important role. The numerical results show how the magnetic subband structure and quantized Hall conductivity emerge as the electric field becomes weaker. In this regime, the behavior can be understood by comparison to the predictions of the adiabatic approximation. The latter predicts crossings in the frequencies at certain locations in wave vector space. Nonadiabatic effects are seen to produce gaps in the frequency spectrum at these locations. 35 refs., 14 figs

  18. Effects of facility backpressure on the performance and plume of a Hall thruster

    Science.gov (United States)

    Walker, Mitchell Louis Ronald

    2005-07-01

    this work aims to develop a fundamental understanding of how multi-kW clustered Hall thrusters operate and how to use single-engine ground-based data to predict the performance, plume interaction, and operation of a cluster. The results show that the plume and operating characteristics of the cluster are governed primarily by the facility backpressure and not the adjacent thruster. At nearly equal backpressure, the thrust is equal to the sum of the thrust of the monolithic thrusters at the lower anode flow rate. At the upper anode flow rate, the sum of the thrust of the monolithic thrusters under predicts the cluster thrust by 5%. This may be caused by each cluster element ingesting unionized propellant from the adjacent thruster. In addition, a cathode sharing investigation shows negligible change in the discharge current and cathode-to-ground voltage for thruster centerline separation distances up to 2 meters. A cathode displacement investigation shows that the Hall thruster starts reliably and performs nominally at cathode separation distances up to 1.1 meters. Collectively, the results of this work shed light on future facility designs that can reduce facility effects at pumping speeds that are not significantly above those of current facilities.

  19. Comparison between cross sections, saddle point and scission point barriers for the 32S+24Mg reaction

    Directory of Open Access Journals (Sweden)

    Santos T. J.

    2014-04-01

    Full Text Available One of the principal characteristics of nuclear multifragmentation is the emission of complex fragments of intermediate mass. The statistical multifragmentation model has been used for many years to describe the distribution of these fragments. An extension of the statistical multifragmentation model to include partial widths and lifetimes for emission, interprets the fragmentation process as the near simultaneous limit of a series of sequential binary decays. In this extension, the expression describing intermediate mass fragment emission is almost identical to that of light particle emission. At lower temperatures, similar expressions have been shown to furnish a good description of very light intermediate mass fragment emission. However, this is usually not considered a good approximation to the emission of heavier fragments. These emissions seem to be determined by the characteristics of the system at the saddle-point and its subsequent dynamical evolution rather than by the scission point. Here, we compare the barriers and decay widths of these different formulations of intermediate fragment emission and analyze the extent to which they remain distinguishable at high excitation energy.

  20. Comparison between cross sections, saddle point and scission point barriers for the {sup 32}S+{sup 24}Mg reaction

    Energy Technology Data Exchange (ETDEWEB)

    Santos, T.J.; Carlson, B.V., E-mail: nztiago@gmail.com [Instituto Tecnologia de Aeronautica (ITA), Sao Jose dos Campos, SP (Brazil)

    2014-07-01

    One of the principal characteristics of nuclear multifragmentation is the emission of complex fragments of intermediate mass. The statistical multifragmentation model has been used for many years to describe the distribution of these fragments. An extension of the statistical multifragmentation model to include partial widths and lifetimes for emission, interprets the fragmentation process as the near simultaneous limit of a series of sequential binary decays. In this extension, the expression describing intermediate mass fragment emission is almost identical to that of light particle emission. At lower temperatures, similar expressions have been shown to furnish a good description of very light intermediate mass fragment emission. However, this is usually not considered a good approximation to the emission of heavier fragments. These emissions seem to be determined by the characteristics of the system at the saddle-point and its subsequent dynamical evolution rather than by the scission point. Here, we compare the barriers and decay widths of these different formulations of intermediate fragment emission and analyze the extent to which they remain distinguishable at high excitation energy. (author)

  1. Saddle-like deformation in a dielectric elastomer actuator embedded with liquid-phase gallium-indium electrodes

    Science.gov (United States)

    Wissman, J.; Finkenauer, L.; Deseri, L.; Majidi, C.

    2014-10-01

    We introduce a dielectric elastomer actuator (DEA) composed of liquid-phase Gallium-Indium (GaIn) alloy electrodes embedded between layers of poly(dimethylsiloxane) (PDMS) and examine its mechanics using a specialized elastic shell theory. Residual stresses in the dielectric and sealing layers of PDMS cause the DEA to deform into a saddle-like geometry (Gaussian curvature K <0). Applying voltage Φ to the liquid metal electrodes induces electrostatic pressure (Maxwell stress) on the dielectric and relieves some of the residual stress. This reduces the longitudinal bending curvature and corresponding angle of deflection ϑ. Treating the elastomer as an incompressible, isotropic, NeoHookean solid, we develop a theory based on the principle of minimum potential energy to predict the principal curvatures as a function of Φ. Based on this theory, we predict a dependency of ϑ on Φ that is in strong agreement with experimental measurements performed on a GaIn-PDMS composite. By accurately modeling electromechanical coupling in a soft-matter DEA, this theory can inform improvements in design and fabrication.

  2. On the main anhydrite scenario, illustrated by the example of the NE flank of the Stassfurt saddle

    International Nuclear Information System (INIS)

    Schwandt, A.; Schilder, C.; Rauche, H.; Franzke, H.J.

    1991-09-01

    The non-chloride successions embedded in the salt of the Zechstein with their geomechanical behaviour which is completely different from that of the salt rock play an important part in the assessment of the concrete safety situation in the salt mine destined to serve as a repository. The literature study of this report presents a safety-related assessment of the main anhydrite using the example of the NE flank of the Stassfurt saddle, on the basis of exploratory data and experience and documented data obtained by the authors of this report. The tectonic effects on the main anhydrite are studied in detail. It is found that geomechanical impacts can lead to healed or closed joints getting damaged and thus loose their tightness to water or gas. The most intensive geomechanical stress on the main anhydrite results from the flooding of mines. It is stated that, making pin-pointed investigations of the geological and hydrogeological conditions, natural or man-made hazards to the safety of a repository can be well recognized, characterized, and mastered. (orig./HP) [de

  3. Saddle-like deformation in a dielectric elastomer actuator embedded with liquid-phase gallium-indium electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Wissman, J., E-mail: jwissman@andrew.cmu.edu [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Finkenauer, L. [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Deseri, L. [DICAM, Department of Mechanical, Civil and Environmental Engineering, University of Trento, via Mesiano 77 38123 Trento (Italy); TMHRI-Department of Nanomedicine, The Methodist Hospital Research Institute, 6565 Fannin St., MS B-490 Houston, Texas 77030 (United States); Mechanics, Materials and Computing Center, CEE and ME-CIT, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Majidi, C. [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Robotics Institute and Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

    2014-10-14

    We introduce a dielectric elastomer actuator (DEA) composed of liquid-phase Gallium-Indium (GaIn) alloy electrodes embedded between layers of poly(dimethylsiloxane) (PDMS) and examine its mechanics using a specialized elastic shell theory. Residual stresses in the dielectric and sealing layers of PDMS cause the DEA to deform into a saddle-like geometry (Gaussian curvature K<0). Applying voltage Φ to the liquid metal electrodes induces electrostatic pressure (Maxwell stress) on the dielectric and relieves some of the residual stress. This reduces the longitudinal bending curvature and corresponding angle of deflection ϑ. Treating the elastomer as an incompressible, isotropic, NeoHookean solid, we develop a theory based on the principle of minimum potential energy to predict the principal curvatures as a function of Φ. Based on this theory, we predict a dependency of ϑ on Φ that is in strong agreement with experimental measurements performed on a GaIn-PDMS composite. By accurately modeling electromechanical coupling in a soft-matter DEA, this theory can inform improvements in design and fabrication.

  4. Saddle-like deformation in a dielectric elastomer actuator embedded with liquid-phase gallium-indium electrodes

    International Nuclear Information System (INIS)

    Wissman, J.; Finkenauer, L.; Deseri, L.; Majidi, C.

    2014-01-01

    We introduce a dielectric elastomer actuator (DEA) composed of liquid-phase Gallium-Indium (GaIn) alloy electrodes embedded between layers of poly(dimethylsiloxane) (PDMS) and examine its mechanics using a specialized elastic shell theory. Residual stresses in the dielectric and sealing layers of PDMS cause the DEA to deform into a saddle-like geometry (Gaussian curvature K<0). Applying voltage Φ to the liquid metal electrodes induces electrostatic pressure (Maxwell stress) on the dielectric and relieves some of the residual stress. This reduces the longitudinal bending curvature and corresponding angle of deflection ϑ. Treating the elastomer as an incompressible, isotropic, NeoHookean solid, we develop a theory based on the principle of minimum potential energy to predict the principal curvatures as a function of Φ. Based on this theory, we predict a dependency of ϑ on Φ that is in strong agreement with experimental measurements performed on a GaIn-PDMS composite. By accurately modeling electromechanical coupling in a soft-matter DEA, this theory can inform improvements in design and fabrication.

  5. Temperature dependence of collapse of quantized hall resistance

    International Nuclear Information System (INIS)

    Tanaka, Hiroyasu; Kawashima, Hironori; Iizuka, Hisamitsu; Fukuda, Hideaki; Kawaji, Shinji

    2006-01-01

    Similarity is observed in the deviation of Hall resistance from the quantized value with the increase in the source-drain current I SD in our butterfly-type Hall bars and in the Hall bars used by Jeanneret et al., while changes in the diagonal resistivity ρ xx with I SD are significantly different between these Hall bars. The temperature dependence of the critical Hall electric field F cr (T) for the collapse of R H (4) measured in these Hall bars is approximated using F cr (T) = F cr (0)(1 - (T/T cr ) 2 ). Here, the critical Hall electric field at zero temperature depends on the magnetic field B as F cr (0) ∝ B 3/2 . Theoretical considerations are given on F cr (T) on the basis of a temperature-dependent mobility edge model and a schema of temperature-dependent inter-Landau level tunneling probability arising from the Fermi distribution function. The former does not fit in with the I SD dependence of activation energy in ρ xx . (author)

  6. Spontaneous Hall effect in a chiral p-wave superconductor

    Science.gov (United States)

    Furusaki, Akira; Matsumoto, Masashige; Sigrist, Manfred

    2001-08-01

    In a chiral superconductor with broken time-reversal symmetry a ``spontaneous Hall effect'' may be observed. We analyze this phenomenon by taking into account the surface properties of a chiral superconductor. We identify two main contributions to the spontaneous Hall effect. One contribution originates from the Bernoulli (or Lorentz) force due to spontaneous currents running along the surfaces of the superconductor. The other contribution has a topological origin and is related to the intrinsic angular momentum of Cooper pairs. The latter can be described in terms of a Chern-Simons-like term in the low-energy field theory of the superconductor and has some similarities with the quantum Hall effect. The spontaneous Hall effect in a chiral superconductor is, however, nonuniversal. Our analysis is based on three approaches to the problem: a self-consistent solution of the Bogoliubov-de Gennes equation, a generalized Ginzburg-Landau theory, and a hydrodynamic formulation. All three methods consistently lead to the same conclusion that the spontaneous Hall resistance of a two-dimensional superconducting Hall bar is of order h/(ekFλ)2, where kF is the Fermi wave vector and λ is the London penetration depth; the Hall resistance is substantially suppressed from a quantum unit of resistance. Experimental issues in measuring this effect are briefly discussed.

  7. Hall current effects in dynamic magnetic reconnection solutions

    International Nuclear Information System (INIS)

    Craig, I.J.D.; Heerikhuisen, J.; Watson, P.G.

    2003-01-01

    The impact of Hall current contributions on flow driven planar magnetic merging solutions is discussed. The Hall current is important if the dimensionless Hall parameter (or normalized ion skin depth) satisfies c H >η, where η is the inverse Lundquist number for the plasma. A dynamic analysis of the problem shows, however, that the Hall current initially manifests itself, not by modifying the planar reconnection field, but by inducing a non-reconnecting perpendicular 'separator' component in the magnetic field. Only if the stronger condition c H 2 >η is satisfied can Hall currents be expected to affect the planar merging. These analytic predictions are then tested by performing a series of numerical experiments in periodic geometry, using the full system of planar magnetohydrodynamic (MHD) equations. The numerical results confirm that the nature of the merging changes dramatically when the Hall coupling satisfies c H 2 >η. In line with the analytic treatment of sheared reconnection, the coupling provided by the Hall term leads to the emergence of multiple current layers that can enhance the global Ohmic dissipation at the expense of the reconnection rate. However, the details of the dissipation depend critically on the symmetries of the simulation, and when the merging is 'head-on' (i.e., comprises fourfold symmetry) the reconnection rate can be enhanced

  8. Graphene and the universality of the quantum Hall effect

    DEFF Research Database (Denmark)

    Tzalenchuk, A.; Janssen, T. J.B.M.; Kazakova, O.

    2013-01-01

    The quantum Hall effect allows the standard for resistance to be defined in terms of the elementary charge and Planck's constant alone. The effect comprises the quantization of the Hall resistance in two-dimensional electron systems in rational fractions of RK=h/e2=25812.8074434(84) Ω (Mohr P. J....... the unconventional quantum Hall effect and then present in detail the route, which led to the most precise quantum Hall resistance universality test ever performed.......The quantum Hall effect allows the standard for resistance to be defined in terms of the elementary charge and Planck's constant alone. The effect comprises the quantization of the Hall resistance in two-dimensional electron systems in rational fractions of RK=h/e2=25812.8074434(84) Ω (Mohr P. J....... et al., Rev. Mod. Phys., 84 (2012) 1527), the resistance quantum. Despite 30 years of research into the quantum Hall effect, the level of precision necessary for metrology, a few parts per billion, has been achieved only in silicon and III-V heterostructure devices. In this lecture we show...

  9. Signal conditioning and processing for metallic Hall sensors.

    Czech Academy of Sciences Publication Activity Database

    Entler, Slavomír; Ďuran, Ivan; Sládek, P.; Vayakis, G.; Kočan, M.

    2017-01-01

    Roč. 123, November (2017), s. 783-786 ISSN 0920-3796. [SOFT 2016: Symposium on Fusion Technology /29./. Prague, 05.09.2016-09.09.2016] R&D Projects: GA MŠk LG14002 Institutional support: RVO:61389021 Keywords : Hall sensor * Lock-in * Synchronous detection * Current spinning * Hall effect * Planar hall effect suppression Subject RIV: JF - Nuclear Energetics OBOR OECD: Nuclear related engineering Impact factor: 1.319, year: 2016 http://www.sciencedirect.com/science/article/pii/S0920379617305070

  10. Anomalous Hall effect in Fe/Gd bilayers

    KAUST Repository

    Xu, W. J.; Zhang, Bei; Liu, Z. X.; Wang, Z.; Li, W.; Wu, Z. B.; Yu, R. H.; Zhang, Xixiang

    2010-01-01

    Non-monotonic dependence of anomalous Hall resistivity on temperature and magnetization, including a sign change, was observed in Fe/Gd bilayers. To understand the intriguing observations, we fabricated the Fe/Gd bilayers and single layers of Fe and Gd simultaneously. The temperature and field dependences of longitudinal resistivity, Hall resistivity and magnetization in these films have also been carefully measured. The analysis of these data reveals that these intriguing features are due to the opposite signs of Hall resistivity/or spin polarization and different Curie temperatures of Fe and Gd single-layer films. Copyright (C) EPLA, 2010

  11. Hall conductance and topological invariant for open systems.

    Science.gov (United States)

    Shen, H Z; Wang, W; Yi, X X

    2014-09-24

    The Hall conductivity given by the Kubo formula is a linear response of quantum transverse transport to a weak electric field. It has been intensively studied for quantum systems without decoherence, but it is barely explored for systems subject to decoherence. In this paper, we develop a formulism to deal with this issue for topological insulators. The Hall conductance of a topological insulator coupled to an environment is derived, the derivation is based on a linear response theory developed for open systems in this paper. As an application, the Hall conductance of a two-band topological insulator and a two-dimensional lattice is presented and discussed.

  12. Acoustic investigations of concert halls for rock music

    DEFF Research Database (Denmark)

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2007-01-01

    Objective measurement data and subjective evaluations have been collected from 20 small-/medium-sized halls in Denmark used for amplified rhythmic music concerts (pop, rock, jazz). The purpose of the study was to obtain knowledge about optimum acoustic conditions for this type of hall. The study...... is motivated by the fact that most concert tickets sold in Denmark relate to concerts within these genres in this kind of venue. The subjective evaluations were carried out by professional musicians and sound engineers who responded on the basis of their experiences working in these (and other) halls. From...

  13. Anomalous Hall effect in Fe/Gd bilayers

    KAUST Repository

    Xu, W. J.

    2010-04-01

    Non-monotonic dependence of anomalous Hall resistivity on temperature and magnetization, including a sign change, was observed in Fe/Gd bilayers. To understand the intriguing observations, we fabricated the Fe/Gd bilayers and single layers of Fe and Gd simultaneously. The temperature and field dependences of longitudinal resistivity, Hall resistivity and magnetization in these films have also been carefully measured. The analysis of these data reveals that these intriguing features are due to the opposite signs of Hall resistivity/or spin polarization and different Curie temperatures of Fe and Gd single-layer films. Copyright (C) EPLA, 2010

  14. All Optical Measurement Proposed for the Photovoltaic Hall Effect

    International Nuclear Information System (INIS)

    Oka, Takashi; Aoki, Hideo

    2011-01-01

    We propose an all optical way to measure the recently proposed p hotovoltaic Hall effect , i.e., a Hall effect induced by a circularly polarized light in the absence of static magnetic fields. This is done in a pump-probe experiment with the Faraday rotation angle being the probe. The Floquet extended Kubo formula for photo-induced optical response is formulated and the ac-Hall conductivity is calculated. We also point out the possibility of observing the effect in two layered graphene, three-dimensional graphite, and more generally in multi-band systems such as materials described by the dp-model.

  15. Determination of intrinsic spin Hall angle in Pt

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yi; Deorani, Praveen; Qiu, Xuepeng; Kwon, Jae Hyun; Yang, Hyunsoo, E-mail: eleyang@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 117576 (Singapore)

    2014-10-13

    The spin Hall angle in Pt is evaluated in Pt/NiFe bilayers by spin torque ferromagnetic resonance measurements and is found to increase with increasing the NiFe thickness. To extract the intrinsic spin Hall angle in Pt by estimating the total spin current injected into NiFe from Pt, the NiFe thickness dependent measurements are performed and the spin diffusion in the NiFe layer is taken into account. The intrinsic spin Hall angle of Pt is determined to be 0.068 at room temperature and is found to be almost constant in the temperature range of 13–300 K.

  16. Determination of intrinsic spin Hall angle in Pt

    International Nuclear Information System (INIS)

    Wang, Yi; Deorani, Praveen; Qiu, Xuepeng; Kwon, Jae Hyun; Yang, Hyunsoo

    2014-01-01

    The spin Hall angle in Pt is evaluated in Pt/NiFe bilayers by spin torque ferromagnetic resonance measurements and is found to increase with increasing the NiFe thickness. To extract the intrinsic spin Hall angle in Pt by estimating the total spin current injected into NiFe from Pt, the NiFe thickness dependent measurements are performed and the spin diffusion in the NiFe layer is taken into account. The intrinsic spin Hall angle of Pt is determined to be 0.068 at room temperature and is found to be almost constant in the temperature range of 13–300 K.

  17. The ISOLDE experimental hall, wth the isotope separator in the upper left corner.

    CERN Multimedia

    CERN PhotoLab

    1969-01-01

    Beam tubes branch out from a switchyard, which by electrostatic deflectors direct beams of short-lived isotopes to various spectroscopic equipment. From left to right, Rudi Stoeckli at the separator control panel, Gilbert Droz and Henri Bersinger.

  18. Properties of Nonabelian Quantum Hall States

    Science.gov (United States)

    Simon, Steven H.

    2004-03-01

    The quantum statistics of particles refers to the behavior of a multiparticle wavefunction under adiabatic interchange of two identical particles. While a three dimensional world affords the possibilities of Bosons or Fermions, the two dimensional world has more exotic possibilities such as Fractional and Nonabelian statistics (J. Frölich, in ``Nonperturbative Quantum Field Theory", ed, G. t'Hooft. 1988). The latter is perhaps the most interesting where the wavefunction obeys a ``nonabelian'' representation of the braid group - meaning that braiding A around B then B around C is not the same as braiding B around C then A around B. This property enables one to think about using these exotic systems for robust topological quantum computation (M. Freedman, A. Kitaev, et al, Bull Am Math Soc 40, 31 (2003)). Surprisingly, it is thought that quasiparticles excitations with such nonabelian statistics may actually exist in certain quantum Hall states that have already been observed. The most likely such candidate is the quantum Hall ν=5/2 state(R. L. Willett et al, Phys. Rev. Lett. 59, 1776-1779 (1987)), thought to be a so-called Moore-Read Pfaffian state(G. Moore and N. Read, Nucl Phys. B360 362 (1991)), which can be thought of as a p-wave paired superconducting state of composite fermions(M. Greiter, X. G. Wen, and F. Wilczek, PRL 66, 3205 (1991)). Using this superconducting analogy, we use a Chern-Simons field theory approach to make a number of predictions as to what experimental signatures one should expect for this state if it really is this Moore-Read state(K. Foster, N. Bonesteel, and S. H. Simon, PRL 91 046804 (2003)). We will then discuss how the nonabelian statistics can be explored in detail using a quantum monte-carlo approach (Y. Tserkovnyak and S. H. Simon, PRL 90 106802 (2003)), (I. Finkler, Y. Tserkovnyak, and S. H. Simon, work in progress.) that allows one to explicitly drag one particle around another and observe the change in the wavefunctions

  19. Quantum Theory of Conducting Matter Superconductivity and Quantum Hall Effect

    CERN Document Server

    Fujita, Shigeji; Godoy, Salvador

    2009-01-01

    Explains major superconducting properties including zero resistance, Meissner effect, sharp phase change, flux quantization, excitation energy gap, and Josephson effects using quantum statistical mechanical calculations. This book covers the 2D superconductivity and the quantum Hall effects

  20. Magnesium Hall Thruster for Solar System Exploration, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation being developed in this program is a Mg Hall Effect Thruster system that would open the door for In-Situ Resource Utilization based solar system...

  1. W∞ gauge theory and the quantum Hall effect

    International Nuclear Information System (INIS)

    Shizuya, K.

    1994-05-01

    It is shown that a planar system of Hall electrons coupled to an applied electromagnetic field is written in the form of a W ∞ gauge theory. The associated W ∞ gauge field is expressed nonlinearly in terms of an infinite set of multipoles of the electromagnetic field. The W ∞ transformations generate mixing among the Landau levels. They provide a systematic way to classify the electromagnetic characteristics of the Hall system according to the resolution of external probes. In particular, an exact long-wavelength connection is derived between the carrier density and the Hall conductance in the presence of electron-electron interactions. Our approach is complementary to an earlier one and reveals a dual role the W ∞ gauge symmetry plays in the Hall dynamics. (author)

  2. Magnetohydrodynamic simulations of Gamble I POS with Hall effect

    International Nuclear Information System (INIS)

    Roderick, N.F.; Frese, M.H.; Peterkin, R.E.; Payne, S.S.

    1989-01-01

    Two dimensional single fluid magnetohydrodynamic simulations have been conducted to investigate the effects of the Hall electric field on magnetic field transport in plasma opening switches of the type used on Gamble I. The Hall terms were included in the magnetic field transport equation in the two dimensional simulation code MACH2 through the use of a generalized Ohm's law. Calculations show the Hall terms augment the field transport previously observed to occur through ion fluid motion and diffusion. For modest values of microturbulent collision frequency, board current channels were observed . Results also show the magnetic field transport to be affected by the cathode boundary conditions with the Hall terms included. In all cases center of mass motion was slight

  3. The Dream Comes True in the Golden Hall

    Institute of Scientific and Technical Information of China (English)

    JianZhong; ChenJianguo

    2004-01-01

    Nanjing Traditional Music Ensemble has long dreamed of performing in Vienna's Golden Hall.Now the dream has come true.the whole troupe felt so exciting that they did not even sleep well during the flight.

  4. Observation of the anomalous Hall effect in GaAs

    International Nuclear Information System (INIS)

    Miah, M Idrish

    2007-01-01

    Devices for the direct detection of the spin current, based on the anomalous Hall effect (AHE), are fabricated on n-type GaAs bulk semiconductor materials. The AHE is observed in the device when the photoinduced spin-polarized electrons are injected into it, and it is found that the effect depends on the applied electric field. The origin of the field-dependent observed Hall effect is discussed based on the D'yakonov-Perel' (DP) spin relaxation mechanism. The spin-dependent Hall effect is also found to be enhanced with increasing doping concentration. The present experimental results might have potential applications in semiconductor spintronic devices since the effect is closely related to the spin Hall effect

  5. Observation of the anomalous Hall effect in GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M Idrish [Nanoscale Science and Technology Centre, School of Science, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong, Chittagong - 4331 (Bangladesh)

    2007-03-21

    Devices for the direct detection of the spin current, based on the anomalous Hall effect (AHE), are fabricated on n-type GaAs bulk semiconductor materials. The AHE is observed in the device when the photoinduced spin-polarized electrons are injected into it, and it is found that the effect depends on the applied electric field. The origin of the field-dependent observed Hall effect is discussed based on the D'yakonov-Perel' (DP) spin relaxation mechanism. The spin-dependent Hall effect is also found to be enhanced with increasing doping concentration. The present experimental results might have potential applications in semiconductor spintronic devices since the effect is closely related to the spin Hall effect.

  6. Nobel Prize in physics 1985: Quantum Hall effect

    International Nuclear Information System (INIS)

    Herrmann, R.

    1986-01-01

    The conditions (like very strong magnetic fields, ultralow temperatures, and occurrence of a two-dimensional electron gas in microelectronic structures) for the measurement of the quantum Hall effect are explained. Two possible measuring methods are described. Measuring results for p-Si-MOSFET, GaAs/AlGaAs heterojuntions and grain boundaries in InSb crystals are reported. Differences between normal (integer) and fractional quantum Hall effect are discussed. One of the important consequences is that by means of the quantum Hall effect the value h/e 2 can be determined with very high accuracy. In 1985 Klaus von Klitzing was awarded the Nobel Prize for his work on the quantum Hall effect

  7. Quantum Computing With Quasiparticles of the Fractional Quantum Hall Effect

    National Research Council Canada - National Science Library

    Averin, Dmitri

    2001-01-01

    The focus of this project was the theoretical study of quantum computation based on controlled transfer of individual quasiparticles in systems of quantum antidots in the regime of the Fractional Quantum Hall Effect (FQHE...

  8. Quantum Hall Ferroelectrics and Nematics in Multivalley Systems

    Science.gov (United States)

    Sodemann, Inti; Zhu, Zheng; Fu, Liang

    2017-10-01

    We study broken symmetry states at integer Landau-level fillings in multivalley quantum Hall systems whose low-energy dispersions are anisotropic. When the Fermi surface of individual pockets lacks twofold rotational symmetry, like in bismuth (111) [Feldman et al. , Observation of a Nematic Quantum Hall Liquid on the Surface of Bismuth, Science 354, 316 (2016), 10.1126/science.aag1715] and in Sn1 -xPbxSe (001) [Dziawa et al., Topological Crystalline Insulator States in Pb1 -xSnxSe , Nat. Mater. 11, 1023 (2012), 10.1038/nmat3449] surfaces, interactions tend to drive the formation of quantum Hall ferroelectric states. We demonstrate that the dipole moment in these states has an intimate relation to the Fermi surface geometry of the parent metal. In quantum Hall nematic states, like those arising in AlAs quantum wells, we demonstrate the existence of unusually robust Skyrmion quasiparticles.

  9. Hall effects and related phenomena in disordered Rashba 2DEG

    International Nuclear Information System (INIS)

    Inoue, Jun-ichiro; Kato, Takashi; Bauer, Gerrit E W; Molenkamp, Laurens W

    2009-01-01

    We review our recent work on the spin and anomalous Hall effects and other related phenomena caused by the intrinsic spin–orbit interaction. We focus our attention on disorder effects on these transport properties by adopting a model of a two-dimensional electron gas with a Rashba-type spin–orbit interaction. A spin-polarized model is adopted to calculate the anomalous Hall effect and anisotropic magnetoresistance. It is shown that the spin Hall conductivity in the ballistic transport regime is cancelled by the so-called vertex corrections for the disorder scattering, and that the anomalous Hall conductivity and anisotropic magnetoresistance vanish unless the lifetime is spin dependent. We further present results on spin accumulation under an electric field

  10. Dual Mode Low Power Hall Thruster, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Sample and return missions desire and missions like Saturn Observer require a low power Hall thruster that can operate at high thrust to power as well as high...

  11. Suitable reverberation time for halls for rock and pop music

    DEFF Research Database (Denmark)

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2010-01-01

    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of popular music, including rock and pop. Objective measurements were made of the acoustics of 20 rock music venues in Denmark....... The best-rated halls in the study have reverberation times that are approximately frequency independent from 0.6 to 1.2 s for hall volumes from 1000 to 6000 m3. The worst rated halls in the study had significantly higher reverberation times in the 63 and 125 Hz bands. Since most audiences at rock concerts...... are standing, absorption coefficients were measured with a standing audience from 63 Hz to 4 kHz. These measurements showed that a standing audience absorbs about five times as much energy in mid-/high-frequency bands as in low-frequency bands....

  12. Analysis of Hall Probe Precise Positioning with Cylindrical Permanent Magnet

    International Nuclear Information System (INIS)

    Belicev, P.; Vorozhtsov, A.S.; Vorozhtsov, S.B.

    2007-01-01

    Precise positioning of a Hall probe for cyclotron magnetic field mapping, using cylindrical permanent magnets, was analyzed. The necessary permanent magnet parameters in order to achieve ±20 μm position precision, were determined. (author)

  13. High Input Voltage Hall Thruster Discharge Converter, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall scope of this Phase I/II effort is the development of a high efficiency 15kW (nominal) Hall thruster discharge converter. In Phase I, Busek Co. Inc. will...

  14. Pragmatic data fusion uncertainty concerns: Tribute to Dave L. Hall

    CSIR Research Space (South Africa)

    Blasch, E

    2016-07-01

    Full Text Available Over the course of Dave Hall's career, he highlighted various concerns associated with the implementation of data fusion methods. Many of the issues included the role of uncertainty in data fusion, practical implementation of sensor fusion systems...

  15. 2D Electrostatic Potential Solver for Hall Thruster Simulation

    National Research Council Canada - National Science Library

    Koo, Justin W

    2006-01-01

    ...) for Hall thruster simulation. It is based on a finite volume discretization of a current conservation equation where the electron current density is described by a Generalized Ohm's law description...

  16. Precision of single-engage micro Hall effect measurements

    DEFF Research Database (Denmark)

    Henrichsen, Henrik Hartmann; Hansen, Ole; Kjær, Daniel

    2014-01-01

    Recently a novel microscale Hall effect measurement technique has been developed to extract sheet resistance (RS), Hall sheet carrier density (NHS) and Hall mobility (μH) from collinear micro 4-point probe measurements in the vicinity of an insulating boundary [1]. The technique measures in less...... than a minute directly the local transport properties, which enables in-line production monitoring on scribe line test pads [2]. To increase measurement speed and reliability, a method in which 4-point measurements are performed using two different electrode pitches has been developed [3......]. In this study we calculate the measurement error on RS, NHS and μH resulting from electrode position errors, probe placement, sample size and Hall signal magnitude. We show the relationship between measurement precision and electrode pitch, which is important when down-scaling the micro 4-point probe to fit...

  17. The integer quantum hall effect revisited

    Energy Technology Data Exchange (ETDEWEB)

    Michalakis, Spyridon [Los Alamos National Laboratory; Hastings, Matthew [Q STATION, CALIFORNIA

    2009-01-01

    For T - L x L a finite subset of Z{sup 2}, let H{sub o} denote a Hamiltonian on T with periodic boundary conditions and finite range, finite strength intetactions and a unique ground state with a nonvanishing spectral gap. For S {element_of} T, let q{sub s} denote the charge at site s and assume that the total charge Q = {Sigma}{sub s {element_of} T} q{sub s} is conserved. Using the local charge operators q{sub s}, we introduce a boundary magnetic flux in the horizontal and vertical direction and allow the ground state to evolve quasiadiabatically around a square of size one magnetic flux, in flux space. At the end of the evolution we obtain a trivial Berry phase, which we compare, via a method reminiscent of Stokes Theorem. to the Berry phase obtained from an evolution around an exponentially small loop near the origin. As a result, we show, without any averaging assumption, that the Hall conductance is quantized in integer multiples of e{sup 2}/h up to exponentially small corrections of order e{sup -L/{zeta}}, where {zeta}, is a correlation length that depends only on the gap and the range and strength of the interactions.

  18. Brand new hall in the main building

    CERN Multimedia

    Corinne Pralavorio

    2014-01-01

    The renovation of the UNIQA and post office premises is getting under way, with their reopening scheduled for the spring.   The renovation of the large hall in the main building (Building 500) has finally reached the home straight. As of this week, building contractors will get to work on the last part – the offices of UNIQA and La Poste. In the last week of November, the two concessions moved their offices across Route Scherrer to the same part of Building 510 where UBS was temporarily housed during the bank’s refurbishment. Their services were therefore unavailable for one day. The renovation work will last until the spring, with the new offices expected to open in May 2015. Between now and then, the windows and insulation will be completely refitted, with a view to reducing heat loss considerably, and, above all, the premises will be modernised to improve customer reception and service. For example, UNIQA’s new premises will feature a confidential area, guarantee...

  19. Acoustics in Halls for Speech and Music

    Science.gov (United States)

    Gade, Anders C.

    This chapter deals specifically with concepts, tools, and architectural variables of importance when designing auditoria for speech and music. The focus will be on cultivating the useful components of the sound in the room rather than on avoiding noise from outside or from installations, which is dealt with in Chap. 11. The chapter starts by presenting the subjective aspects of the room acoustic experience according to consensus at the time of writing. Then follows a description of their objective counterparts, the objective room acoustic parameters, among which the classical reverberation time measure is only one of many, but still of fundamental value. After explanations on how these parameters can be measured and predicted during the design phase, the remainder of the chapter deals with how the acoustic properties can be controlled by the architectural design of auditoria. This is done by presenting the influence of individual design elements as well as brief descriptions of halls designed for specific purposes, such as drama, opera, and symphonic concerts. Finally, some important aspects of loudspeaker installations in auditoria are briefly touched upon.

  20. Hall MHD reconnection in cometary magnetotail

    International Nuclear Information System (INIS)

    Jovanovic, Dusan; Shukla, Padma Kant; Morfill, Gregor

    2005-01-01

    The fine structure of cometary tails (swirls, loops and blobs) is studied in the framework of resistive magnetic reconnection without a guide field in a dusty plasma. For a high-beta plasma (β ∼ 1) consisting of electrons, ions, and immobile dust grains, a two-fluid description is used to study electromagnetic perturbations with the frequency below Ωi, propagating at an arbitrary angle, and including the effects of Hall current. A zero-order current associated with the anti-parallel magnetic configuration may exist even in the limit of zero plasma temperature in a dusty plasma due to a symmetry breaking between electrons and ions by dust grains that yields an E-vector x B-vector current. In the perturbed state, a new linear electromagnetic mode is found in dusty plasma which is evanescent below the Rao cut-off frequency and has the characteristic wavelength comparable to the ion skin depth, which enables the reconnection at short spatial scales. The role of the dust is found to be twofold, yielding a new mode outside of the current sheet and altering the continuity conditions at its edge by an inhomogeneous Doppler shift associated with the E-vector x B-vector current

  1. Linear waves in a resistive plasma with Hall current

    International Nuclear Information System (INIS)

    Almaguer, J.A.

    1992-01-01

    Dispersion relations for the case of a magnetized plasma are determined taking into account the Hall current and a constant resistivity, η, in Ohm's law. It is found that the Hall effect is relevant only for parallel (to the equilibrium magnetic field) wave numbers in the case of uniform plasmas, giving place to a dispersive behavior. In particular, the cases of η→0 and small (nonzero) resistivity are discussed

  2. Hall effect in the two-dimensional Luttinger liquid

    International Nuclear Information System (INIS)

    Anderson, P.W.

    1991-01-01

    The temperature dependence of the Hall effect in the normal state is a commom theme of all the cuprate superconductors and has been one of the more puzzling observations on these puzzling materials. We describe a general scheme within the Luttinger liquid theory of these two-dimensional quantum fluids which corrrelates the anomalous Hall and resistivity observations on a wide variety of both pure and doped single crystals, especially the data in the accompanying Letter of Chien, Wang, and Ong

  3. Thermoelectric and Hall-effect studies in hydrogenerated nickel foils

    International Nuclear Information System (INIS)

    Rani, R.; Nigam, A.N.

    1978-01-01

    Thermo e.m.f. and Hall constant of hydrogenerated nickel foils have been measured. Termo e.m.f. shows a sign reversal which is not due to the change in sign of the charge carriers, as indicated by the Hall-effect measurements. To account for the sign reversal of thermo e.m.f., it is found necessary to take into account the surface states of chemisorbed hydrogen on nickel

  4. Fractional statistics and fractional quantized Hall effect. Revision

    International Nuclear Information System (INIS)

    Tao, R.; Wu, Y.S.

    1984-01-01

    We suggest that the origin of the odd denominator rule observed in the fractional quantized Hall effect (FQHE) may lie in fractional statistics which governs quasiparticles in FQHE. A theorem concerning statistics of clusters of quasiparticles implies that fractional statistics does not allow coexistence of a large number of quasiparticles at fillings with an even denominator. Thus no Hall plateau can be formed at these fillings, regardless of the presence of an energy gap. 15 references

  5. Low-Cost, High-Performance Hall Thruster Support System

    Science.gov (United States)

    Hesterman, Bryce

    2015-01-01

    Colorado Power Electronics (CPE) has built an innovative modular PPU for Hall thrusters, including discharge, magnet, heater and keeper supplies, and an interface module. This high-performance PPU offers resonant circuit topologies, magnetics design, modularity, and a stable and sustained operation during severe Hall effect thruster current oscillations. Laboratory testing has demonstrated discharge module efficiency of 96 percent, which is considerably higher than current state of the art.

  6. High-performance LED luminaire for sports hall

    Science.gov (United States)

    Lee, Xuan-Hao; Yang, Jin-Tsung; Chien, Wei-Ting; Chang, Jung-Hsuan; Lo, Yi-Chien; Lin, Che-Chu; Sun, Ching-Cherng

    2015-09-01

    In this paper, we present a luminaire design with anti-glare and energy-saving effects for sports hall. Compared with traditional lamps using in a badminton court, the average illuminance on the ground of the proposed LED luminaire is enhanced about 300%. Besides, the uniformity is obviously enhanced and improved. The switch-on speed of lighting in sports hall is greatly reduced from 5-10 minutes to 1 second. The simulation analysis and the corresponding experiment results are demonstrated.

  7. Upper Gastrointestinal (GI) Series

    Science.gov (United States)

    ... standard barium upper GI series, which uses only barium a double-contrast upper GI series, which uses both air and ... evenly coat your upper GI tract with the barium. If you are having a double-contrast study, you will swallow gas-forming crystals that ...

  8. Anisotropic intrinsic spin Hall effect in quantum wires

    International Nuclear Information System (INIS)

    Cummings, A W; Akis, R; Ferry, D K

    2011-01-01

    We use numerical simulations to investigate the spin Hall effect in quantum wires in the presence of both Rashba and Dresselhaus spin-orbit coupling. We find that the intrinsic spin Hall effect is highly anisotropic with respect to the orientation of the wire, and that the nature of this anisotropy depends strongly on the electron density and the relative strengths of the Rashba and Dresselhaus spin-orbit couplings. In particular, at low densities, when only one subband of the quantum wire is occupied, the spin Hall effect is strongest for electron momentum along the [1-bar 10] axis, which is the opposite of what is expected for the purely 2D case. In addition, when more than one subband is occupied, the strength and anisotropy of the spin Hall effect can vary greatly over relatively small changes in electron density, which makes it difficult to predict which wire orientation will maximize the strength of the spin Hall effect. These results help to illuminate the role of quantum confinement in spin-orbit-coupled systems, and can serve as a guide for future experimental work on the use of quantum wires for spin-Hall-based spintronic applications. (paper)

  9. The quantum Hall's effect: A quantum electrodynamic phenomenon

    International Nuclear Information System (INIS)

    Arbab, A. I.

    2012-01-01

    We have applied Maxwell's equations to study the physics of quantum Hall's effect. The electromagnetic properties of this system are obtained. The Hall's voltage, V H = 2πħ 2 n s /em, where n s is the electron number density, for a 2-dimensional system, and h = 2πħ is the Planck's constant, is found to coincide with the voltage drop across the quantum capacitor. Consideration of the cyclotronic motion of electrons is found to give rise to Hall's resistance. Ohmic resistances in the horizontal and vertical directions have been found to exist before equilibrium state is reached. At a fundamental level, the Hall's effect is found to be equivalent to a resonant LCR circuit with L H = 2π m/e 2 n s and C H = me 2 /2πħ 2 n s satisfying the resonance condition with resonant frequency equal to the inverse of the scattering (relaxation) time, τ s . The Hall's resistance is found to be R H = √L H /C H . The Hall's resistance may be connected with the impedance that the electron wave experiences when it propagates in the 2-dimensional gas. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  10. Signatures of lattice geometry in quantum and topological Hall effect

    International Nuclear Information System (INIS)

    Göbel, Börge; Mook, Alexander; Mertig, Ingrid; Henk, Jürgen

    2017-01-01

    The topological Hall effect (THE) of electrons in skyrmion crystals (SkXs) is strongly related to the quantum Hall effect (QHE) on lattices. This relation suggests to revisit the QHE because its Hall conductivity can be unconventionally quantized. It exhibits a jump and changes sign abruptly if the Fermi level crosses a van Hove singularity. In this Paper, we investigate the unconventional QHE features by discussing band structures, Hall conductivities, and topological edge states for square and triangular lattices; their origin are Chern numbers of bands in the SkX (THE) or of the corresponding Landau levels (QHE). Striking features in the energy dependence of the Hall conductivities are traced back to the band structure without magnetic field whose properties are dictated by the lattice geometry. Based on these findings, we derive an approximation that allows us to determine the energy dependence of the topological Hall conductivity on any two-dimensional lattice. The validity of this approximation is proven for the honeycomb lattice. We conclude that SkXs lend themselves for experiments to validate our findings for the THE and—indirectly—the QHE. (paper)

  11. Tunnelling anomalous and planar Hall effects (Conference Presentation)

    Science.gov (United States)

    Matos-Abiague, Alex; Scharf, Benedikt; Han, Jong E.; Hankiewicz, Ewelina M.; Zutic, Igor

    2016-10-01

    We theoretically show how the interplay between spin-orbit coupling (SOC) and magnetism can result in a finite tunneling Hall conductance, transverse to the applied bias. For two-dimensional tunnel junctions with a ferromagnetic lead and magnetization perpendicular to the current flow, the detected anomalous Hall voltage can be used to extract information not only about the spin polarization but also about the strength of the interfacial SOC. In contrast, a tunneling current across a ferromagnetic barrier on the surface of a three-dimensional topological insulator (TI) can induce a planar Hall response even when the magnetization is oriented along the current flow[1]. The tunneling nature of the states contributing to the planar Hall conductance can be switched from the ordinary to the Klein regimes by the electrostatic control of the barrier strength. This allows for an enhancement of the transverse response and a giant Hall angle, with the tunneling planar Hall conductance exceeding the longitudinal component. Despite the simplicity of a single ferromagnetic region, the TI/ferromagnet system exhibits a variety of functionalities. In addition to a spin-valve operation for magnetic sensing and storing information, positive, negative, and negative differential conductances can be tuned by properly adjusting the barrier potential and/or varying the magnetization direction. Such different resistive behaviors in the same system are attractive for potential applications in reconfigurable spintronic devices. [1] B. Scharf, A. Matos-Abiague, J. E. Han, E. M. Hankiewicz, and I. Zutic, arXiv:1601.01009 (2016).

  12. A holographic model for the fractional quantum Hall effect

    Energy Technology Data Exchange (ETDEWEB)

    Lippert, Matthew [Institute for Theoretical Physics, University of Amsterdam,Science Park 904, 1090GL Amsterdam (Netherlands); Meyer, René [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo,Kashiwa, Chiba 277-8568 (Japan); Taliotis, Anastasios [Theoretische Natuurkunde, Vrije Universiteit Brussel andThe International Solvay Institutes,Pleinlaan 2, B-1050 Brussels (Belgium)

    2015-01-08

    Experimental data for fractional quantum Hall systems can to a large extent be explained by assuming the existence of a Γ{sub 0}(2) modular symmetry group commuting with the renormalization group flow and hence mapping different phases of two-dimensional electron gases into each other. Based on this insight, we construct a phenomenological holographic model which captures many features of the fractional quantum Hall effect. Using an SL(2,ℤ)-invariant Einstein-Maxwell-axio-dilaton theory capturing the important modular transformation properties of quantum Hall physics, we find dyonic diatonic black hole solutions which are gapped and have a Hall conductivity equal to the filling fraction, as expected for quantum Hall states. We also provide several technical results on the general behavior of the gauge field fluctuations around these dyonic dilatonic black hole solutions: we specify a sufficient criterion for IR normalizability of the fluctuations, demonstrate the preservation of the gap under the SL(2,ℤ) action, and prove that the singularity of the fluctuation problem in the presence of a magnetic field is an accessory singularity. We finish with a preliminary investigation of the possible IR scaling solutions of our model and some speculations on how they could be important for the observed universality of quantum Hall transitions.

  13. A holographic model for the fractional quantum Hall effect

    Science.gov (United States)

    Lippert, Matthew; Meyer, René; Taliotis, Anastasios

    2015-01-01

    Experimental data for fractional quantum Hall systems can to a large extent be explained by assuming the existence of a Γ0(2) modular symmetry group commuting with the renormalization group flow and hence mapping different phases of two-dimensional electron gases into each other. Based on this insight, we construct a phenomenological holographic model which captures many features of the fractional quantum Hall effect. Using an -invariant Einstein-Maxwell-axio-dilaton theory capturing the important modular transformation properties of quantum Hall physics, we find dyonic diatonic black hole solutions which are gapped and have a Hall conductivity equal to the filling fraction, as expected for quantum Hall states. We also provide several technical results on the general behavior of the gauge field fluctuations around these dyonic dilatonic black hole solutions: we specify a sufficient criterion for IR normalizability of the fluctuations, demonstrate the preservation of the gap under the action, and prove that the singularity of the fluctuation problem in the presence of a magnetic field is an accessory singularity. We finish with a preliminary investigation of the possible IR scaling solutions of our model and some speculations on how they could be important for the observed universality of quantum Hall transitions.

  14. DISK FORMATION IN MAGNETIZED CLOUDS ENABLED BY THE HALL EFFECT

    International Nuclear Information System (INIS)

    Krasnopolsky, Ruben; Shang, Hsien; Li Zhiyun

    2011-01-01

    Stars form in dense cores of molecular clouds that are observed to be significantly magnetized. A dynamically important magnetic field presents a significant obstacle to the formation of protostellar disks. Recent studies have shown that magnetic braking is strong enough to suppress the formation of rotationally supported disks in the ideal MHD limit. Whether non-ideal MHD effects can enable disk formation remains unsettled. We carry out a first study on how disk formation in magnetic clouds is modified by the Hall effect, the least explored of the three non-ideal MHD effects in star formation (the other two being ambipolar diffusion and Ohmic dissipation). For illustrative purposes, we consider a simplified problem of a non-self-gravitating, magnetized envelope collapsing onto a central protostar of fixed mass. We find that the Hall effect can spin up the inner part of the collapsing flow to Keplerian speed, producing a rotationally supported disk. The disk is generated through a Hall-induced magnetic torque. Disk formation occurs even when the envelope is initially non-rotating, provided that the Hall coefficient is large enough. When the magnetic field orientation is flipped, the direction of disk rotation is reversed as well. The implication is that the Hall effect can in principle produce both regularly rotating and counter-rotating disks around protostars. The Hall coefficient expected in dense cores is about one order of magnitude smaller than that needed for efficient spin-up in these models. We conclude that the Hall effect is an important factor to consider in studying the angular momentum evolution of magnetized star formation in general and disk formation in particular.

  15. An intermittent control model of flexible human gait using a stable manifold of saddle-type unstable limit cycle dynamics.

    Science.gov (United States)

    Fu, Chunjiang; Suzuki, Yasuyuki; Kiyono, Ken; Morasso, Pietro; Nomura, Taishin

    2014-12-06

    Stability of human gait is the ability to maintain upright posture during walking against external perturbations. It is a complex process determined by a number of cross-related factors, including gait trajectory, joint impedance and neural control strategies. Here, we consider a control strategy that can achieve stable steady-state periodic gait while maintaining joint flexibility with the lowest possible joint impedance. To this end, we carried out a simulation study of a heel-toe footed biped model with hip, knee and ankle joints and a heavy head-arms-trunk element, working in the sagittal plane. For simplicity, the model assumes a periodic desired joint angle trajectory and joint torques generated by a set of feed-forward and proportional-derivative feedback controllers, whereby the joint impedance is parametrized by the feedback gains. We could show that a desired steady-state gait accompanied by the desired joint angle trajectory can be established as a stable limit cycle (LC) for the feedback controller with an appropriate set of large feedback gains. Moreover, as the feedback gains are decreased for lowering the joint stiffness, stability of the LC is lost only in a few dimensions, while leaving the remaining large number of dimensions quite stable: this means that the LC becomes saddle-type, with a low-dimensional unstable manifold and a high-dimensional stable manifold. Remarkably, the unstable manifold remains of low dimensionality even when the feedback gains are decreased far below the instability point. We then developed an intermittent neural feedback controller that is activated only for short periods of time at an optimal phase of each gait stride. We characterized the robustness of this design by showing that it can better stabilize the unstable LC with small feedback gains, leading to a flexible gait, and in particular we demonstrated that such an intermittent controller performs better if it drives the state point to the stable manifold, rather

  16. How does the suppression of energy supplementation affect herbage intake, performance and parasitism in lactating saddle mares?

    Science.gov (United States)

    Collas, C; Fleurance, G; Cabaret, J; Martin-Rosset, W; Wimel, L; Cortet, J; Dumont, B

    2014-08-01

    Agroecology opens up new perspectives for the design of sustainable farming systems by using the stimulation of natural processes to reduce the inputs needed for production. In horse farming systems, the challenge is to maximize the proportion of forages in the diet, and to develop alternatives to synthetic chemical drugs for controlling gastrointestinal nematodes. Lactating saddle mares, with high nutritional requirements, are commonly supplemented with concentrates at pasture, although the influence of energy supplementation on voluntary intake, performance and immune response against parasites has not yet been quantified. In a 4-month study, 16 lactating mares experimentally infected with cyathostome larvae either received a daily supplement of barley (60% of energy requirements for lactation) or were non-supplemented. The mares were rotationally grazed on permanent pastures over three vegetation cycles. All the mares met their energy requirements and maintained their body condition score higher than 3. In both treatments, they produced foals with a satisfying growth rate (cycle 1: 1293 g/day; cycle 2: 1029 g/day; cycle 3: 559 g/day) and conformation (according to measurements of height at withers and cannon bone width at 11 months). Parasite egg excretion by mares increased in both groups during the grazing season (from 150 to 2011 epg), independently of whether they were supplemented or not. This suggests that energy supplementation did not improve mare ability to regulate parasite burden. Under unlimited herbage conditions, grass dry matter intake by supplemented mares remained stable around 22.6 g DM/kg LW per day (i.e. 13.5 kg DM/al per day), whereas non-supplemented mares increased voluntary intake from 22.6 to 28.0 g DM/kg LW per day (13.5 to 17.2 kg DM/al per day) between mid-June and the end of August. Hence total digestible dry matter intake and net energy intake did not significantly differ between supplemented and non-supplemented mares during the

  17. Saddle-shaped porphyrins for dye-sensitized solar cells: new insight into the relationship between nonplanarity and photovoltaic properties.

    Science.gov (United States)

    Shahroosvand, Hashem; Zakavi, Saeed; Sousaraei, Ahmad; Eskandari, Mortaza

    2015-03-07

    We report on the theoretical and experimental studies of the new dye-sensitized solar cells functionalized with 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin zinc(II) complexes bearing 2- and 8-bromo substituents at the β positions. In agreement with the results of TD-DFT calculations, the absorption maxima of di- and octa-brominated Zn(II) complexes, ZnTCPPBr2 and ZnTCPPBr8, exhibited large red-shift compared to that of the non-brominated free base porphyrin (H2TCPP). Furthermore, DFT calculations showed that the higher stabilization of the LUMO levels relative to the HOMO ones makes the HOMO-LUMO gap of the brominated Zn-porphyrins models smaller compared to that of the nonbrominated counterparts, which explains the red shifts of the Soret and Q bands of the brominated compounds. Solar cells containing the new saddle-shaped Zn(II) porphyrins were subjected to analysis in a photovoltaic calibration laboratory to determine their solar to electric energy conversion. In this regard, we found that the overall conversion efficiency of ZnTCPPBr8 adsorbed on TiO2 nanocrystalline films was 5 times as large as that of ZnTCPPBr2 adsorbed on the same films. The effect of the increasing number of Br groups on the photovoltaic performance of the complexes was compared to the results of computational methods using ab initio DFT molecular dynamics simulations and quantum dynamics calculations of electronic relaxation to investigate the interfacial electron transfer (IET) in TCPPBrx/TiO2-anatase nanostructures. Better IET in ZnTCPPBr8 compared to ZnTCPPBr2, and in H2TCPP was evaluated from interfacial electron transfer (IET) simulations. The IET results indicate that electron injection in ZnTCPPBr8-TiO2 (τ = 25 fs) can be up to 5 orders of magnitude faster than ZnTCPPBr2-TiO2 (τ = 125 fs). Both experimental and theoretical results demonstrate that the increase of the number of bromo-substituents at the β-pyrrole positions of the porphyrin macrocycle created a new class of

  18. Summary and evaluation of hydraulic property data available for the Hanford Site upper basalt confined aquifer system

    International Nuclear Information System (INIS)

    Spane, F.A. Jr.; Vermeul, V.R.

    1994-09-01

    Pacific Northwest Laboratory, as part of the Hanford Site Ground-Water Surveillance Project, examines the potential for offsite migration of contamination within the upper basalt confined aquifer system. For the past 40 years, hydrologic testing of the upper basalt confined aquifer has been conducted by a number of Hanford Site programs. Hydraulic property estimates are important for evaluating aquifer flow characteristics (i.e., ground-water flow patterns, flow velocity, transport travel time). Presented are the first comprehensive Hanford Site-wide summary of hydraulic properties for the upper basalt confined aquifer system (i.e., the upper Saddle Mountains Basalt). Available hydrologic test data were reevaluated using recently developed diagnostic test analysis methods. A comparison of calculated transmissivity estimates indicates that, for most test results, a general correspondence within a factor of two between reanalysis and previously reported test values was obtained. For a majority of the tests, previously reported values are greater than reanalysis estimates. This overestimation is attributed to a number of factors, including, in many cases, a misapplication of nonleaky confined aquifer analysis methods in previous analysis reports to tests that exhibit leaky confined aquifer response behavior. Results of the test analyses indicate a similar range for transmissivity values for the various hydro-geologic units making up the upper basalt confined aquifer. Approximately 90% of the calculated transmissivity values for upper basalt confined aquifer hydrogeologic units occur within the range of 10 0 to 10 2 m 2 /d, with 65% of the calculated estimate values occurring between 10 1 to 10 2 m 2 d. These summary findings are consistent with the general range of values previously reported for basalt interflow contact zones and sedimentary interbeds within the Saddle Mountains Basalt

  19. Hamaoka Atomic Energy Hall, Chubu Electric Power Co. , Inc

    Energy Technology Data Exchange (ETDEWEB)

    Kawasaki, Y [Chubu Electric Power Co. Inc., Nagoya (Japan)

    1979-10-01

    Hamaoka Nuclear Power Station was constructed in the very large site of about 1.6 million m/sup 2/ surrounded by sand dunes and pine forests at the southern tip of Shizuoka Prefecture. Hamaoka Atomic Energy Hall was built on the right side of this power station. This hall had been planned as a part of the works commemorating the 20th anniversary of the founding of the company, and was opened in August, 1972. The building is of steel frame type, and has two floors of 1135 m/sup 2/ total area. The first floor comprises cinema room, power generation corner and open gallery, and the second floor comprises meeting room, native land corner and observation room. Moreover, there is observation platform on the roof. The purpose of the hall is coexistence and coprosperity with the regional residents, and 13 persons make explanations to visitors having reached to 1.9 million as of the end of June, 1979. It is incorporated in the sightseeing route centering around the Omaezaki lighthouse. The cinema hall accommodates 120 men, and the films concerning nuclear power generation and the construction of a nuclear power plant are shown. In the power generation corner, the explanation on nuclear power generation is made with models and panels. The third hall is being built now as energy corner, and it will be completed in autumn, 1979.

  20. Hamaoka Atomic Energy Hall, Chubu Electric Power Co., Inc

    International Nuclear Information System (INIS)

    Kawasaki, Yukio

    1979-01-01

    Hamaoka Nuclear Power Station was constructed in the very large site of about 1.6 million m 2 surrounded by sand dunes and pine forests at the southern tip of Shizuoka Prefecture. Hamaoka Atomic Energy Hall was built on the right side of this power station. This hall had been planned as a part of the works commemorating the 20th anniversary of the founding of the company, and was opened in August, 1972. The building is of steel frame type, and has two floors of 1135 m 2 total area. The first floor comprises cinema room, power generation corner and open gallery, and the second floor comprises meeting room, native land corner and observation room. Moreover, there is observation platform on the roof. The purpose of the hall is coexistence and coprosperity with the regional residents, and 13 persons make explanations to visitors having reached to 1.9 million as of the end of June, 1979. It is incorporated in the sightseeing route centering around the Omaezaki lighthouse. The cinema hall accommodates 120 men, and the films concerning nuclear power generation and the construction of a nuclear power plant are shown. In the power generation corner, the explanation on nuclear power generation is made with models and panels. The third hall is being built now as energy corner, and it will be completed in autumn, 1979. (Kako, I.)

  1. Higher (odd dimensional quantum Hall effect and extended dimensional hierarchy

    Directory of Open Access Journals (Sweden)

    Kazuki Hasebe

    2017-07-01

    Full Text Available We demonstrate dimensional ladder of higher dimensional quantum Hall effects by exploiting quantum Hall effects on arbitrary odd dimensional spheres. Non-relativistic and relativistic Landau models are analyzed on S2k−1 in the SO(2k−1 monopole background. The total sub-band degeneracy of the odd dimensional lowest Landau level is shown to be equal to the winding number from the base-manifold S2k−1 to the one-dimension higher SO(2k gauge group. Based on the chiral Hopf maps, we clarify the underlying quantum Nambu geometry for odd dimensional quantum Hall effect and the resulting quantum geometry is naturally embedded also in one-dimension higher quantum geometry. An origin of such dimensional ladder connecting even and odd dimensional quantum Hall effects is illuminated from a viewpoint of the spectral flow of Atiyah–Patodi–Singer index theorem in differential topology. We also present a BF topological field theory as an effective field theory in which membranes with different dimensions undergo non-trivial linking in odd dimensional space. Finally, an extended version of the dimensional hierarchy for higher dimensional quantum Hall liquids is proposed, and its relationship to quantum anomaly and D-brane physics is discussed.

  2. G. Stanley Hall, Child Study, and the American Public.

    Science.gov (United States)

    Young, Jacy L

    2016-01-01

    In the final decades of the 19th century psychologist Granville Stanley Hall was among the most prominent pedagogical experts in the nation. The author explores Hall's carefully crafted persona as an educational expert, and his engagements with the American public, from 1880 to 1900, arguably the height of his influence. Drawing from accounts of Hall's lecture circuit in the popular press, a map of his talks across the nation is constructed to assess the geographic scope of his influence. These talks to educators on the psychology underlying childhood and pedagogy, and his views and research on child life more generally, were regularly discussed in newspapers and popular periodicals. The venues in which Hall's ideas were disseminated, discussed, and in some cases, dismissed are described. His efforts to mobilize popular support for, and assistance with, his research endeavors in child study are also discussed. Such efforts were controversial both within the burgeoning field of psychology and among the public. Through his various involvements in pedagogy, and concerted efforts to engage with the American public, Hall helped establish psychology's relevance to parenting and educational practices.

  3. Scanning Hall Probe Microscopy of Magnetic Vortices inVery Underdoped yttrium-barium-copper-oxide

    Energy Technology Data Exchange (ETDEWEB)

    Guikema, Janice Wynn; /SLAC, SSRL

    2005-12-02

    Since their discovery by Bednorz and Mueller (1986), high-temperature cuprate superconductors have been the subject of intense experimental research and theoretical work. Despite this large-scale effort, agreement on the mechanism of high-T{sub c} has not been reached. Many theories make their strongest predictions for underdoped superconductors with very low superfluid density n{sub s}/m*. For this dissertation I implemented a scanning Hall probe microscope and used it to study magnetic vortices in newly available single crystals of very underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} (Liang et al. 1998, 2002). These studies have disproved a promising theory of spin-charge separation, measured the apparent vortex size (an upper bound on the penetration depth {lambda}{sub ab}), and revealed an intriguing phenomenon of ''split'' vortices. Scanning Hall probe microscopy is a non-invasive and direct method for magnetic field imaging. It is one of the few techniques capable of submicron spatial resolution coupled with sub-{Phi}{sub 0} (flux quantum) sensitivity, and it operates over a wide temperature range. Chapter 2 introduces the variable temperature scanning microscope and discusses the scanning Hall probe set-up and scanner characterizations. Chapter 3 details my fabrication of submicron GaAs/AlGaAs Hall probes and discusses noise studies for a range of probe sizes, which suggest that sub-100 nm probes could be made without compromising flux sensitivity. The subsequent chapters detail scanning Hall probe (and SQUID) microscopy studies of very underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} crystals with T{sub c} {le} 15 K. Chapter 4 describes two experimental tests for visons, essential excitations of a spin-charge separation theory proposed by Senthil and Fisher (2000, 2001b). We searched for predicted hc/e vortices (Wynn et al. 2001) and a vortex memory effect (Bonn et al. 2001) with null results, placing upper bounds on the vison energy inconsistent with

  4. Seville City Hall Chapter Room ceiling decoration

    Directory of Open Access Journals (Sweden)

    Robador, M. D.

    2010-02-01

    Full Text Available The present article describes a chemical and physical study of the colour, chemical composition and mineral phases of the decorative materials in the Seville City Hall Chapter House ceiling. The findings showed that the inner most layer of material, calcite, was covered with white lead, in turn concealed under a layer of gilded bole. The ceiling underwent re-gilding, also over bole, due in all likelihood to wear on the original gold leaf. In the nineteenth century, the entire ceiling with the exception of the inscriptions was whitewashed with calcite and white lead. Silver was employed on King John I’s sword (coffer 27. Gold leaf was used to adorn the royal attributes: crowns, belts, sceptres, swords and rosary beads. The high reliefs were likewise gilded. The pigments identified on the ceiling adornments included azurite, malachite, vermilion and gas black. A lime and ground dolomite mortar was used throughout.

    El objetivo de este trabajo es el estudio de diferentes aspectos, como el color, la composición química y las fases mineralógicas presentes en los diferentes materiales que forman la ornamentación del techo de la Sala Capitular del Ayuntamiento de Sevilla, mediante métodos físicos y químicos. Nuestros resultados muestran que el dorado fue realizado sobre una capa de bol previamente depositada sobre una lámina de blanco de plomo que cubría un estrato de calcita. Posteriormente, y probablemente debido a alteraciones en el dorado original, el techo fue de nuevo dorado usando una técnica similar. En el siglo XIX, casi todo el techo, excepto las zonas con inscripciones, fue blanqueado usando una mezcla de calcita y blanco de plomo. Se empleó plata para cubrir la espada del rey Juan I (casetón 27. Finísimas láminas de oro se usaron para decorar los atributos reales: coronas, cinturones, cetros, espadas y rosarios. En diferentes partes de la decoración fueron detectados pigmentos como azurita, malaquita, bermellón y

  5. Trends in preference, programming and design of concert halls for symphonic music

    DEFF Research Database (Denmark)

    Gade, Anders Christian

    2008-01-01

    This paper discusses the evolution in taste regarding concert hall acoustics and how this can be reflected in the new halls being built today. The clients' and listener's preferences are not only based on listening in existing halls; but also on listening to reproduced music recorded with microph......This paper discusses the evolution in taste regarding concert hall acoustics and how this can be reflected in the new halls being built today. The clients' and listener's preferences are not only based on listening in existing halls; but also on listening to reproduced music recorded...

  6. Carl Gustav Jung and Granville Stanley Hall on Religious Experience.

    Science.gov (United States)

    Kim, Chae Young

    2016-08-01

    Granville Stanley Hall (1844-1924) with William James (1842-1910) is the key founder of psychology of religion movement and the first American experimental or genetic psychologist, and Carl Gustav Jung (1875-1961) is the founder of the analytical psychology concerned sympathetically about the religious dimension rooted in the human subject. Their fundamental works are mutually connected. Among other things, both Hall and Jung were deeply interested in how the study of religious experience is indispensable for the depth understanding of human subject. Nevertheless, except for the slight indication, this common interest between them has not yet been examined in academic research paper. So this paper aims to articulate preliminary evidence of affinities focusing on the locus and its function of the inner deep psychic dimension as the religious in the work of Hall and Jung.

  7. Admittance of multiterminal quantum Hall conductors at kilohertz frequencies

    International Nuclear Information System (INIS)

    Hernández, C.; Consejo, C.; Chaubet, C.; Degiovanni, P.

    2014-01-01

    We present an experimental study of the low frequency admittance of quantum Hall conductors in the [100 Hz, 1 MHz] frequency range. We show that the frequency dependence of the admittance of the sample strongly depends on the topology of the contacts connections. Our experimental results are well explained within the Christen and Büttiker approach for finite frequency transport in quantum Hall edge channels taking into account the influence of the coaxial cables capacitance. In the Hall bar geometry, we demonstrate that there exists a configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the sample and observe its dependence on the filling factor

  8. Admittance of multiterminal quantum Hall conductors at kilohertz frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, C. [Departamento de Física, Universidad Militar Nueva Granada, Carrera 11 101-80 Bogotá D.C. (Colombia); Consejo, C.; Chaubet, C., E-mail: christophe.chaubet@univ-montp2.fr [Université Montpellier 2, Laboratoire Charles Coulomb UMR5221, F-34095 Montpellier, France and CNRS, Laboratoire Charles Coulomb UMR5221, F-34095 Montpellier (France); Degiovanni, P. [Université de Lyon, Fédération de Physique Andrée Marie Ampère, CNRS, Laboratoire de Physique de l' Ecole Normale Supérieure de Lyon, 46 allée d' Italie, 69364 Lyon Cedex 07 (France)

    2014-03-28

    We present an experimental study of the low frequency admittance of quantum Hall conductors in the [100 Hz, 1 MHz] frequency range. We show that the frequency dependence of the admittance of the sample strongly depends on the topology of the contacts connections. Our experimental results are well explained within the Christen and Büttiker approach for finite frequency transport in quantum Hall edge channels taking into account the influence of the coaxial cables capacitance. In the Hall bar geometry, we demonstrate that there exists a configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the sample and observe its dependence on the filling factor.

  9. Crossover between spin swapping and Hall effect in disordered systems

    KAUST Repository

    Saidaoui, Hamed Ben Mohamed

    2015-07-16

    We theoretically study the crossover between spin Hall effect and spin swapping, a recently predicted phenomenon that consists of the interchange between the current flow and its spin polarization directions [M. B. Lifshits and M. I. Dyakonov, Phys. Rev. Lett. 103, 186601 (2009)]. Using a tight-binding model with spin-orbit coupled disorder, spin Hall effect, spin relaxation, and spin swapping are treated on equal footing. We demonstrate that spin swapping and spin Hall effect present very different dependencies as a function of the spin-orbit coupling and disorder strengths and confirm that the former exceeds the latter in the parameter range considered. Three setups are proposed for the experimental observation of the spin swapping effect.

  10. The quantum Hall effect in quantum dot systems

    International Nuclear Information System (INIS)

    Beltukov, Y M; Greshnov, A A

    2014-01-01

    It is proposed to use quantum dots in order to increase the temperatures suitable for observation of the integer quantum Hall effect. A simple estimation using Fock-Darwin spectrum of a quantum dot shows that good part of carriers localized in quantum dots generate the intervals of plateaus robust against elevated temperatures. Numerical calculations employing local trigonometric basis and highly efficient kernel polynomial method adopted for computing the Hall conductivity reveal that quantum dots may enhance peak temperature for the effect by an order of magnitude, possibly above 77 K. Requirements to potentials, quality and arrangement of the quantum dots essential for practical realization of such enhancement are indicated. Comparison of our theoretical results with the quantum Hall measurements in InAs quantum dot systems from two experimental groups is also given

  11. Diaphragm Effect of Steel Space Roof Systems in Hall Structures

    Directory of Open Access Journals (Sweden)

    Mehmet FENKLİ

    2015-09-01

    Full Text Available Hall structures have been used widely for different purposes. They have are reinforced concrete frames and shear wall with steel space roof systems. Earthquake response of hall structures is different from building type structures. One of the most critical nodes is diaphragm effect of steel space roof on earthquake response of hall structures. Diaphragm effect is depending on lateral stiffness capacity of steel space roof system. Lateral stiffness of steel space roof system is related to modulation geometry, support conditions, selected sections and system geometry. In current paper, three representative models which are commonly used in Turkey were taken in to account for investigation. Results of numerical tests were present comparatively

  12. Novel Hall sensors developed for magnetic field imaging systems

    International Nuclear Information System (INIS)

    Cambel, Vladimir; Karapetrov, Goran; Novosad, Valentyn; Bartolome, Elena; Gregusova, Dagmar; Fedor, Jan; Kudela, Robert; Soltys, Jan

    2007-01-01

    We report here on the fabrication and application of novel planar Hall sensors based on shallow InGaP/AlGaAs/GaAs heterostructure with a two-dimensional electron gas (2DEG) as an active layer. The sensors are developed for two kinds of experiments. In the first one, magnetic samples are placed directly on the Hall sensor. Room temperature experiments of permalloy objects evaporated onto the sensor are presented. In the second experiment, the sensor scans close over a multigranular superconducting sample prepared on a YBCO thin film. Large-area and high-resolution scanning experiments were performed at 4.2 K with the Hall probe scanning system in a liquid helium flow cryostat

  13. Crossover between spin swapping and Hall effect in disordered systems

    KAUST Repository

    Saidaoui, Hamed Ben Mohamed; Otani, Y.; Manchon, Aurelien

    2015-01-01

    We theoretically study the crossover between spin Hall effect and spin swapping, a recently predicted phenomenon that consists of the interchange between the current flow and its spin polarization directions [M. B. Lifshits and M. I. Dyakonov, Phys. Rev. Lett. 103, 186601 (2009)]. Using a tight-binding model with spin-orbit coupled disorder, spin Hall effect, spin relaxation, and spin swapping are treated on equal footing. We demonstrate that spin swapping and spin Hall effect present very different dependencies as a function of the spin-orbit coupling and disorder strengths and confirm that the former exceeds the latter in the parameter range considered. Three setups are proposed for the experimental observation of the spin swapping effect.

  14. ε-iron nitrides: Intrinsic anomalous Hall ferromagnets

    Directory of Open Access Journals (Sweden)

    Guo-Ke Li

    2015-02-01

    Full Text Available The anomalous Hall effect in ε-iron nitrides (ε-Fe3-xN, 0 ≤ x ≤ 1 has been systematically investigated taking advantage of the fact that the exchange splitting of ε-Fe3-xN can be continuously tuned through the nitrogen concentration. It has been found that the anomalous Hall conductivity, σ x y A H , is proportional to the saturation magnetization MS, i.e., σ x y A H = S H M S , across significant variations in the saturation magnetization (96–1146 emu/cc. This relationship is in excellent agreement with the intrinsic mechanism as well as with the unified theory of AHE. Our results also demonstrate that the anomalous Hall conductivity is sensitive to the exchange splitting of the band structure.

  15. Can ensemble condition in a hall be improved and measured?

    DEFF Research Database (Denmark)

    Gade, Anders Christian

    1988-01-01

    of the ceiling reflectors; and (c) changing the position of the orchestra on the platform. These variables were then tested in full scale experiments in the hall including subjective evaluation by the orchestra in order to verify their effects under practical conditions. New objective parameters, which showed......In collaboration with the Danish Broadcasting Corporation an extensive series of experiments has been carried out in The Danish Radio Concert Hall with the practical purpose of trying to improve the ensemble conditions on the platform for the resident symphony orchestra. First, a series...... very high correlations with the subjective data, also made it possible to compare the improvements with conditions as recently measured in famous European Halls. Besides providing the needed results, the experiments also shed some light on how musicians change their criteria for judging acoustic...

  16. Overview of NASA Iodine Hall Thruster Propulsion System Development

    Science.gov (United States)

    Smith, Timothy D.; Kamhawi, Hani; Hickman, Tyler; Haag, Thomas; Dankanich, John; Polzin, Kurt; Byrne, Lawrence; Szabo, James

    2016-01-01

    NASA is continuing to invest in advancing Hall thruster technologies for implementation in commercial and government missions. The most recent focus has been on increasing the power level for large-scale exploration applications. However, there has also been a similar push to examine applications of electric propulsion for small spacecraft in the range of 300 kg or less. There have been several recent iodine Hall propulsion system development activities performed by the team of the NASA Glenn Research Center, the NASA Marshall Space Flight Center, and Busek Co. Inc. In particular, the work focused on qualification of the Busek 200-W BHT-200-I and development of the 600-W BHT-600-I systems. This paper discusses the current status of iodine Hall propulsion system developments along with supporting technology development efforts.

  17. Hall effect in a strong magnetic field: Direct comparisons of compressible magnetohydrodynamics and the reduced Hall magnetohydrodynamic equations

    International Nuclear Information System (INIS)

    Martin, L. N.; Dmitruk, P.; Gomez, D. O.

    2010-01-01

    In this work we numerically test a model of Hall magnetohydrodynamics in the presence of a strong mean magnetic field: the reduced Hall magnetohydrodynamic model (RHMHD) derived by [Gomez et al., Phys. Plasmas 15, 102303 (2008)] with the addition of weak compressible effects. The main advantage of this model lies in the reduction of computational cost. Nevertheless, up until now the degree of agreement with the original Hall MHD system and the range of validity in a regime of turbulence were not established. In this work direct numerical simulations of three-dimensional Hall MHD turbulence in the presence of a strong mean magnetic field are compared with simulations of the weak compressible RHMHD model. The results show that the degree of agreement is very high (when the different assumptions of RHMHD, such as spectral anisotropy, are satisfied). Nevertheless, when the initial conditions are isotropic but the mean magnetic field is maintained strong, the results differ at the beginning but asymptotically reach a good agreement at relatively short times. We also found evidence that the compressibility still plays a role in the dynamics of these systems, and the weak compressible RHMHD model is able to capture these effects. In conclusion the weak compressible RHMHD model is a valid approximation of the Hall MHD turbulence in the relevant physical context.

  18. Spin-Hall nano-oscillator: A micromagnetic study

    Energy Technology Data Exchange (ETDEWEB)

    Giordano, A.; Azzerboni, B.; Finocchio, G. [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, C.da di Dio, I-98166 Messina (Italy); Carpentieri, M. [Department of Electrical and Information Engineering, Politecnico of Bari, via E. Orabona 4, I-70125 Bari (Italy); Laudani, A. [Department of Engineering, University of Roma Tre, via V. Volterra 62, I-00146 Roma (Italy); Gubbiotti, G. [Istituto Officina dei Materiali del CNR (CNR-IOM), Unità di Perugia c/o Dipartimento di Fisica e Geologia, Via A. Pascoli, 06123 Perugia (Italy)

    2014-07-28

    This Letter studies the dynamical behavior of spin-Hall nanoscillators from a micromagnetic point of view. The model parameters have been identified by reproducing recent experimental data quantitatively. Our results indicate that a strongly localized mode is observed for in-plane bias fields such as in the experiments, while predict the excitation of an asymmetric propagating mode for large enough out-of plane bias field similarly to what observed in spin-torque nanocontact oscillators. Our findings show that spin-Hall nanoscillators can find application as spin-wave emitters for magnonic applications where spin waves are used for transmission and processing information on nanoscale.

  19. Complex scattering dynamics and the quantum Hall effects

    International Nuclear Information System (INIS)

    Trugman, S.A.

    1994-01-01

    We review both classical and quantum potential scattering in two dimensions in a magnetic field, with applications to the quantum Hall effect. Classical scattering is complex, due to the approach of scattering states to an infinite number of dynamically bound states. Quantum scattering follows the classical behavior rather closely, exhibiting sharp resonances in place of the classical bound states. Extended scatterers provide a quantitative explanation for the breakdown of the QHE at a comparatively small Hall voltage as seen by Kawaji et al., and possibly for noise effects

  20. Impact of external conditions on energy consumption in industrial halls

    Science.gov (United States)

    Żabnieńśka-Góra, Alina

    2017-11-01

    The energy demand for heating the halls buildings is high. The impact on this may have the technology of production, building construction and technology requirements (HVAC systems). The isolation of the external partitions, the location of the object in relation to the surrounding buildings and the degree of the interior insolation (windows and skylights) are important in the context of energy consumption. The article discusses the impact of external conditions, wind and sunlight on energy demand in the industrial hall. The building model was prepared in IDA ICE 4.0 simulation software. Model validation was done based on measurements taken in the analyzed building.

  1. Hall effects on MHD flow past an accelerated plate

    Directory of Open Access Journals (Sweden)

    Deka R.K.

    2008-01-01

    Full Text Available The simultaneous effects of rotation and Hall current on the hydromagnetic flow past an accelerated horizontal plate relative to a rotating fluid is presented. It is found that for given values of m (Hall parameter, M (Hartmann number and an imposed rotation parameter Ω satisfying Ω = M 2m/(1 + m2, the transverse motion (transverse to the main flow disappears and the fluid moves in the direction of the plate only. The effects of the parameters m, M and Ω on the axial and transverse velocity profiles are shown graphically, whereas the effects of the parameters on the skin-friction components are shown by tabular values.

  2. Spectroscopy of snake states using a graphene Hall bar

    Energy Technology Data Exchange (ETDEWEB)

    Milovanović, S. P., E-mail: slavisa.milovanovic@gmail.com; Ramezani Masir, M., E-mail: mrmphys@gmail.com; Peeters, F. M., E-mail: francois.peeters@ua.ac.be [Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium)

    2013-12-02

    An approach to observe snake states in a graphene Hall bar containing a pn-junction is proposed. The magnetic field dependence of the bend resistance in a ballistic graphene Hall bar structure containing a tilted pn-junction oscillates as a function of applied magnetic field. We show that each oscillation is due to a specific snake state that moves along the pn-interface. Furthermore, depending on the value of the magnetic field and applied potential, we can control the lead in which the electrons will end up and hence control the response of the system.

  3. Theory of spin Hall effect: extension of the Drude model.

    Science.gov (United States)

    Chudnovsky, Eugene M

    2007-11-16

    An extension of the Drude model is proposed that accounts for the spin and spin-orbit interaction of charge carriers. Spin currents appear due to the combined action of the external electric field, crystal field, and scattering of charge carriers. The expression for the spin Hall conductivity is derived for metals and semiconductors that is independent of the scattering mechanism. In cubic metals, the spin Hall conductivity sigma s and charge conductivity sigma c are related through sigma s=[2pi variant /(3mc2)]sigma2c with m being the bare electron mass. The theoretically computed value is in agreement with experiment.

  4. Hall measurements and grain-size effects in polycrystalline silicon

    International Nuclear Information System (INIS)

    Ghosh, A.K.; Rose, A.; Maruska, H.P.; Eustace, D.J.; Feng, T.

    1980-01-01

    The effects of grain size on Hall measurements in polycrystalline silicon are analyzed and interpreted, with some modifications, using the model proposed by Bube. This modified model predicts that the measured effective Hall voltage is composed of components originating from the bulk and space-charge regions. For materials with large grain sizes, the carrier concentration is independent of the intergrain boundary barrier, whereas the mobility is dependent on it. However, for small grains, both the carrier density and mobility depend on the barrier. These predictions are consistent with experimental results of mm-size Wacker and μm-size neutron-transmutation-doped polycrystalline silicon

  5. Fractional quantum Hall states of atoms in optical lattices

    International Nuclear Information System (INIS)

    Soerensen, Anders S.; Demler, Eugene; Lukin, Mikhail D.

    2005-01-01

    We describe a method to create fractional quantum Hall states of atoms confined in optical lattices. We show that the dynamics of the atoms in the lattice is analogous to the motion of a charged particle in a magnetic field if an oscillating quadrupole potential is applied together with a periodic modulation of the tunneling between lattice sites. In a suitable parameter regime the ground state in the lattice is of the fractional quantum Hall type, and we show how these states can be reached by melting a Mott-insulator state in a superlattice potential. Finally, we discuss techniques to observe these strongly correlated states

  6. Theory of the quantized Hall effect. Pt. 3

    International Nuclear Information System (INIS)

    Levine, H.; Pruisken, A.M.M.; Libby, S.B.

    1984-01-01

    In the previous paper, we have demonstrated the need for a phase transition as a function of theta in the non-liner sigma-model describing the quantized Hall effect. In this work, we present arguments for the occurrence of exactly such a transition. We make use of a dilute gas instanton approximation as well as present a more rigorous duality argument to show that the usual scaling of the conductivity to zero at large distances is altered whenever sigmasub(xy)sup((0)) approx.= 1/2ne 2 /h, n integer. This then completes our theory of the quantized Hall effect. (orig.)

  7. Complex dynamics of the integer quantum Hall effect

    International Nuclear Information System (INIS)

    Trugman, S.A.; Nicopoulos, V.N.; Florida Univ., Gainesville, FL

    1991-01-01

    We investigate both classical and quantum potential scattering in two dimensions in a magnetic field, with applications to the integer quantum Hall effect. Classical scattering is complex, due in one case to the approach of scattering states to an infinite number of bound states. We show that bound states are generic, and occur for all but extremely smooth scattering potentials (|rvec ∇| → 0). Quantum scattering follows the classical behavior rather closely, exhibiting sharp resonances rather than classical bound states. Extended scatterers provide an explanation for the breakdown of the QHE at a comparatively small Hall voltage. 16 refs., 14 figs

  8. Spin Hall magnetoresistance in antiferromagnet/normal metal bilayers

    KAUST Repository

    Manchon, Aurelien

    2017-01-01

    We investigate the emergence of spin Hall magnetoresistance in a magnetic bilayer composed of a normal metal adjacent to an antiferromagnet. Based on a recently derived drift diffusion equation, we show that the resistance of the bilayer depends on the relative angle between the direction transverse to the current flow and the Néel order parameter. While this effect presents striking similarities with the spin Hall magnetoresistance recently reported in ferromagnetic bilayers, its physical origin is attributed to the anisotropic spin relaxation of itinerant spins in the antiferromagnet.

  9. Quantum hall fluid on fuzzy two dimensional sphere

    International Nuclear Information System (INIS)

    Luo Xudong; Peng Dantao

    2004-01-01

    After reviewing the Haldane's description about the quantum Hall effect on the fuzzy two-sphere S 2 , authors construct the noncommutative algebra on the fuzzy sphere S 2 and the Moyal structure of the Hilbert space. By constructing noncommutative Chern-Simons theory of the incompressible Hall fluid on the fuzzy sphere and solving the Gaussian constraint with quasiparticle source, authors find the Calogero matrix on S 2 and the complete set of the Laughlin wave function for the lowest Landau level, and this wave function is expressed by the generalized Jack polynomials in terms of spinor coordinates. (author)

  10. Bingo halls and smoking: perspectives of First Nations women.

    Science.gov (United States)

    Bottorff, Joan L; Carey, Joanne; Mowatt, Roberta; Varcoe, Colleen; Johnson, Joy L; Hutchinson, Peter; Sullivan, Debbie; Williams, Wanda; Wardman, Dennis

    2009-12-01

    The purpose of this study was to examine bingo halls as a frequent site for exposure to secondhand cigarette smoke for First Nations women in rural communities. Thematic analysis of interviews with key informants, group discussions with young women, and observations in the study communities revealed that smoky bingo halls provided an important refuge from everyday experiences of stress and trauma, as well as increased women's risk for addiction, marginalization, and criticism. The findings illustrate how the bingo economy in isolated, rural First Nation communities influences tobacco use and second-hand smoke exposure, and how efforts to establish smoke-free bingos can be supported.

  11. Effect of Anode Dielectric Coating on Hall Thruster Operation

    International Nuclear Information System (INIS)

    Dorf, L.; Raitses, Y.; Fisch, N.J.; Semenov, V.

    2003-01-01

    An interesting phenomenon observed in the near-anode region of a Hall thruster is that the anode fall changes from positive to negative upon removal of the dielectric coating, which is produced on the anode surface during the normal course of Hall thruster operation. The anode fall might affect the thruster lifetime and acceleration efficiency. The effect of the anode coating on the anode fall is studied experimentally using both biased and emissive probes. Measurements of discharge current oscillations indicate that thruster operation is more stable with the coated anode

  12. Magnetoresistance and Hall resistivity of semimetal WTe2 ultrathin flakes.

    Science.gov (United States)

    Luo, Xin; Fang, Chi; Wan, Caihua; Cai, Jialin; Liu, Yong; Han, Xiufeng; Lu, Zhihong; Shi, Wenhua; Xiong, Rui; Zeng, Zhongming

    2017-04-07

    This article reports the characterization of WTe 2 thin flake magnetoresistance and Hall resistivity. We found it does not exhibit magnetoresistance saturation when subject to high fields, in a manner similar to their bulk characteristics. The linearity of Hall resistivity in our devices confirms the compensation of electrons and holes. By relating experimental results to a classic two-band model, the lower magnetoresistance values in our samples is demonstrated to be caused by decreased carrier mobility. The dependence of mobility on temperature indicates the main role of optical phonon scattering at high temperatures. Our results provide more detailed information on carrier behavior and scattering mechanisms in WTe 2 thin films.

  13. Measurement of the Hall effect in semiconductors at supersonic frequencies

    International Nuclear Information System (INIS)

    Putyato, I.V.; Sukhanov, S.; Lezhnev, N.B.

    1978-01-01

    A new method of measuring the Hall effect in variable magnetic fields at super-high frequencies using slotted line is proposed. The method is applied to the measurement of the Hall effect in n-InSb samples. It is shown that the level of output signal of samples reduces with the increasing the charge carrier concentration and with decreasing the mobility. But the range of quadratic part of the dependence of the output signal power on the control current increases. It is stated that the output signal of samples does not depend on the magnetic field frequency in the range of 4-7.3 GHz

  14. Measurement of the Hall effect in semiconductors at supersonic frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Putyato, I V; Sukhanov, S; Lezhnev, N B [AN Tadzhikskoj SSR, Khorog. Pamirskij Biologicheskij Inst.

    1978-01-01

    A new method of measuring the Hall effect in variable magnetic fields at super-high frequencies using slotted line is proposed. The method is applied to the measurement of the Hall effect in n-InSb samples. It is shown that the level of output signal of samples reduces with the increasing the charge carrier concentration and with decreasing the mobility. But the range of quadratic part of the dependence of the output signal power on the control current increases. It is stated that the output signal of samples does not depend on the magnetic field frequency in the range of 4-7.3 GHz.

  15. Nonvariceal upper gastrointestinal bleeding

    International Nuclear Information System (INIS)

    Burke, Stephen J.; Weldon, Derik; Sun, Shiliang; Golzarian, Jafar

    2007-01-01

    Nonvariceal upper gastrointestinal bleeding (NUGB) remains a major medical problem even after advances in medical therapy with gastric acid suppression and cyclooxygenase (COX-2) inhibitors. Although the incidence of upper gastrointestinal bleeding presenting to the emergency room has slightly decreased, similar decreases in overall mortality and rebleeding rate have not been experienced over the last few decades. Many causes of upper gastrointestinal bleeding have been identified and will be reviewed. Endoscopic, radiographic and angiographic modalities continue to form the basis of the diagnosis of upper gastrointestinal bleeding with new research in the field of CT angiography to diagnose gastrointestinal bleeding. Endoscopic and angiographic treatment modalities will be highlighted, emphasizing a multi-modality treatment plan for upper gastrointestinal bleeding. (orig.)

  16. Nonvariceal upper gastrointestinal bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Burke, Stephen J.; Weldon, Derik; Sun, Shiliang [University of Iowa, Department of Radiology, Iowa, IA (United States); Golzarian, Jafar [University of Iowa, Department of Radiology, Iowa, IA (United States); University of Iowa, Department of Radiology, Carver College of Medicine, Iowa, IA (United States)

    2007-07-15

    Nonvariceal upper gastrointestinal bleeding (NUGB) remains a major medical problem even after advances in medical therapy with gastric acid suppression and cyclooxygenase (COX-2) inhibitors. Although the incidence of upper gastrointestinal bleeding presenting to the emergency room has slightly decreased, similar decreases in overall mortality and rebleeding rate have not been experienced over the last few decades. Many causes of upper gastrointestinal bleeding have been identified and will be reviewed. Endoscopic, radiographic and angiographic modalities continue to form the basis of the diagnosis of upper gastrointestinal bleeding with new research in the field of CT angiography to diagnose gastrointestinal bleeding. Endoscopic and angiographic treatment modalities will be highlighted, emphasizing a multi-modality treatment plan for upper gastrointestinal bleeding. (orig.)

  17. A new preconditioner update strategy for the solution of sequences of linear systems in structural mechanics: application to saddle point problems in elasticity

    Science.gov (United States)

    Mercier, Sylvain; Gratton, Serge; Tardieu, Nicolas; Vasseur, Xavier

    2017-12-01

    Many applications in structural mechanics require the numerical solution of sequences of linear systems typically issued from a finite element discretization of the governing equations on fine meshes. The method of Lagrange multipliers is often used to take into account mechanical constraints. The resulting matrices then exhibit a saddle point structure and the iterative solution of such preconditioned linear systems is considered as challenging. A popular strategy is then to combine preconditioning and deflation to yield an efficient method. We propose an alternative that is applicable to the general case and not only to matrices with a saddle point structure. In this approach, we consider to update an existing algebraic or application-based preconditioner, using specific available information exploiting the knowledge of an approximate invariant subspace or of matrix-vector products. The resulting preconditioner has the form of a limited memory quasi-Newton matrix and requires a small number of linearly independent vectors. Numerical experiments performed on three large-scale applications in elasticity highlight the relevance of the new approach. We show that the proposed method outperforms the deflation method when considering sequences of linear systems with varying matrices.

  18. Saddle-fin cell transistors with oxide etch rate control by using tilted ion implantation (TIS-fin) for sub-50-nm DRAMs

    International Nuclear Information System (INIS)

    Yoo, Min Soo; Choi, Kang Sik; Sun, Woo Kyung

    2010-01-01

    As DRAM cell pitch size decreases, the need for a high performance transistor is increasing. Though saddle-fin (S-fin) transistors have superior characteristics, S-fin transistors are well known to be more sensitive to process variation. To make uniform S-fin transistors, for the first time, we developed a new fin formation method using tilted ion implantation along the wordline direction after a recess gate etch. Due to the increased etch rate of the oxide film by ion implantation damage, fins are made at the bottom channel of the recess gate after wet etching. The resulting tilt implanted saddle-fin (TIS-fin) transistor has remarkably improved characteristics, such as ∼8% subthreshold swing (SS) and a 40% drain induced barrier lowering (DIBL) decrease. Especially, the TIS-fin with a neutral dopant has a reduced threshold voltage (Vth) variation within a wafer (<100 mV), which is comparable with that of a mass-produced sphere-shaped recessed channel array transistor (SRCAT).

  19. Are quantum spin Hall edge modes more resilient to disorder, sample geometry and inelastic scattering than quantum Hall edge modes?

    Science.gov (United States)

    Mani, Arjun; Benjamin, Colin

    2016-04-13

    On the surface of 2D topological insulators, 1D quantum spin Hall (QSH) edge modes occur with Dirac-like dispersion. Unlike quantum Hall (QH) edge modes, which occur at high magnetic fields in 2D electron gases, the occurrence of QSH edge modes is due to spin-orbit scattering in the bulk of the material. These QSH edge modes are spin-dependent, and chiral-opposite spins move in opposing directions. Electronic spin has a larger decoherence and relaxation time than charge. In view of this, it is expected that QSH edge modes will be more robust to disorder and inelastic scattering than QH edge modes, which are charge-dependent and spin-unpolarized. However, we notice no such advantage accrues in QSH edge modes when subjected to the same degree of contact disorder and/or inelastic scattering in similar setups as QH edge modes. In fact we observe that QSH edge modes are more susceptible to inelastic scattering and contact disorder than QH edge modes. Furthermore, while a single disordered contact has no effect on QH edge modes, it leads to a finite charge Hall current in the case of QSH edge modes, and thus a vanishing of the pure QSH effect. For more than a single disordered contact while QH states continue to remain immune to disorder, QSH edge modes become more susceptible--the Hall resistance for the QSH effect changes sign with increasing disorder. In the case of many disordered contacts with inelastic scattering included, while quantization of Hall edge modes holds, for QSH edge modes a finite charge Hall current still flows. For QSH edge modes in the inelastic scattering regime we distinguish between two cases: with spin-flip and without spin-flip scattering. Finally, while asymmetry in sample geometry can have a deleterious effect in the QSH case, it has no impact in the QH case.

  20. Are quantum spin Hall edge modes more resilient to disorder, sample geometry and inelastic scattering than quantum Hall edge modes?

    International Nuclear Information System (INIS)

    Mani, Arjun; Benjamin, Colin

    2016-01-01

    On the surface of 2D topological insulators, 1D quantum spin Hall (QSH) edge modes occur with Dirac-like dispersion. Unlike quantum Hall (QH) edge modes, which occur at high magnetic fields in 2D electron gases, the occurrence of QSH edge modes is due to spin–orbit scattering in the bulk of the material. These QSH edge modes are spin-dependent, and chiral-opposite spins move in opposing directions. Electronic spin has a larger decoherence and relaxation time than charge. In view of this, it is expected that QSH edge modes will be more robust to disorder and inelastic scattering than QH edge modes, which are charge-dependent and spin-unpolarized. However, we notice no such advantage accrues in QSH edge modes when subjected to the same degree of contact disorder and/or inelastic scattering in similar setups as QH edge modes. In fact we observe that QSH edge modes are more susceptible to inelastic scattering and contact disorder than QH edge modes. Furthermore, while a single disordered contact has no effect on QH edge modes, it leads to a finite charge Hall current in the case of QSH edge modes, and thus a vanishing of the pure QSH effect. For more than a single disordered contact while QH states continue to remain immune to disorder, QSH edge modes become more susceptible—the Hall resistance for the QSH effect changes sign with increasing disorder. In the case of many disordered contacts with inelastic scattering included, while quantization of Hall edge modes holds, for QSH edge modes a finite charge Hall current still flows. For QSH edge modes in the inelastic scattering regime we distinguish between two cases: with spin-flip and without spin-flip scattering. Finally, while asymmetry in sample geometry can have a deleterious effect in the QSH case, it has no impact in the QH case. (paper)

  1. Valley polarized quantum Hall effect and topological insulator phase transitions in silicene

    KAUST Repository

    Tahir, M.; Schwingenschlö gl, Udo

    2013-01-01

    encountered for graphene, in particular the zero band gap and weak spin orbit interaction. We demonstrate a valley polarized quantum Hall effect and topological insulator phase transitions. We use the Kubo formalism to discuss the Hall conductivity and address

  2. Measured Early Lateral Energy Fractions in Concert Halls and Opera Houses

    Science.gov (United States)

    BARRON, M.

    2000-04-01

    In the 30 years since early lateral reflections were first suggested as important for concert halls, spatial impression and source broadening have become almost universally accepted as essential characteristics of halls with good acoustics. Two objective measures of source broadening have been proposed. Measured values of the best defined of these measures, the early lateral energy fraction (LF), are considered here. Results from two independent measurement surveys are discussed. Comparisons of LF values by hall show a significant link between hall mean LF and hall width. There is however considerable overlap between measured LF values in different halls so the relevance of describing halls by their mean early lateral energy fraction values is questionable. The behaviour of LF values within auditoria is discussed for different concert hall plan forms and within opera houses. A measure of source broadening including sound level is proposed and results considered in the context of auditorium design.

  3. A conformal field theory description of fractional quantum Hall states

    NARCIS (Netherlands)

    Ardonne, E.

    2002-01-01

    In this thesis, we give a description of fractional quantum Hall states in terms of conformal field theory (CFT). As was known for a long time, the Laughlin states could be written in terms of correlators of chiral vertex operators of a c=1 CFT. It was shown by G. Moore and N. Read that more general

  4. The Hall-induced stability of gravitating fluids

    Science.gov (United States)

    Karmakar, P. K.; Goutam, H. P.

    2018-05-01

    We analyze the stability behavior of low-density partially ionized self-gravitating magnetized unbounded dusty plasma fluid in the presence of the Hall diffusion effects (HDEs) in the non-ideal magnetohydrodynamic (MHD) equilibrium framework. The effects of inhomogeneous self-gravity are methodically included in the basic model tapestry. Application of the Fourier plane-wave perturbative treatment decouples the structuration representative parameters into a linear generalized dispersion relation (sextic) in a judicious mean-fluid approximation. The dispersion analysis shows that the normal mode, termed as the gravito-magneto-acoustic (GMA) mode, is drastically modified due to the HDEs. This mode is highly dispersive, and driven unstable by the Hall current resulting from the symmetry-breaking of electrons and ions relative to the magnetic field. The mode feature, which is derived from a modified induction with the positive Hall, is against the ideal MHD. It is further demonstrated that the HDEs play stabilizing roles by supporting the cloud against gravitational collapse. Provided that the HDEs are concurrently switched off, the collapse occurs on the global spatial scale due to enhanced inward accretion of the gravitating dust constituents. It is seen explicitly that the enhanced dust-charge leads to stabilizing effects. Besides, the Hall-induced fluctuations, as propagatory wave modes, exhibit both normal and anomalous dispersions. The reliability checkup of the entailed results as diverse corollaries and special cases are illustratively discussed in the panoptic light of the earlier paradigmatic predictions available in the literature.

  5. Numerical simulation of SMART-1 Hall-thruster plasma interactions

    NARCIS (Netherlands)

    Tajmar, Martin; Sedmik, René; Scharlemann, Carsten

    2009-01-01

    SMART-1 has been the first European mission using a Hall thruster to reach the moon. An onboard plasma diagnostic package allowed a detailed characterization of the thruster exhaust plasma and its interactions with the spacecraft. Analysis of in-flight data revealed, amongst others, an unpredicted

  6. Imaging of Coulomb-Driven Quantum Hall Edge States

    KAUST Repository

    Lai, Keji; Kundhikanjana, Worasom; Kelly, Michael A.; Shen, Zhi-Xun; Shabani, Javad; Shayegan, Mansour

    2011-01-01

    The edges of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime are divided into alternating metallic and insulating strips, with their widths determined by the energy gaps of the QHE states and the electrostatic Coulomb

  7. Quantum energy teleportation in a quantum Hall system

    Energy Technology Data Exchange (ETDEWEB)

    Yusa, Go; Izumida, Wataru; Hotta, Masahiro [Department of Physics, Tohoku University, Sendai 980-8578 (Japan)

    2011-09-15

    We propose an experimental method for a quantum protocol termed quantum energy teleportation (QET), which allows energy transportation to a remote location without physical carriers. Using a quantum Hall system as a realistic model, we discuss the physical significance of QET and estimate the order of energy gain using reasonable experimental parameters.

  8. Interaction Induced Quantum Valley Hall Effect in Graphene

    Directory of Open Access Journals (Sweden)

    E. C. Marino

    2015-03-01

    Full Text Available We use pseudo-quantum electrodynamics in order to describe the full electromagnetic interaction of the p electrons in graphene in a consistent 2D formulation. We first consider the effect of this interaction in the vacuum polarization tensor or, equivalently, in the current correlator. This allows us to obtain the T→0 conductivity after a smooth zero-frequency limit is taken in Kubo’s formula. Thereby, we obtain the usual expression for the minimal conductivity plus corrections due to the interaction that bring it closer to the experimental value. We then predict the onset of an interaction-driven spontaneous quantum valley Hall effect below an activation temperature of the order of 2 K. The transverse (Hall valley conductivity is evaluated exactly and shown to coincide with the one in the usual quantum Hall effect. Finally, by considering the effects of pseudo-quantum electrodynamics, we show that the electron self-energy is such that a set of P- and T-symmetric gapped electron energy eigenstates are dynamically generated, in association with the quantum valley Hall effect.

  9. Micro-four-point Probe Hall effect Measurement method

    DEFF Research Database (Denmark)

    Petersen, Dirch Hjorth; Hansen, Ole; Lin, Rong

    2008-01-01

    barriers and with a magnetic field applied normal to the plane of the sheet. Based on this potential, analytical expressions for the measured four-point resistance in presence of a magnetic field are derived for several simple sample geometries. We show how the sheet resistance and Hall effect...

  10. Magnetic microbead detection using the planar Hall effect

    International Nuclear Information System (INIS)

    Ejsing, Louise; Hansen, Mikkel F.; Menon, Aric K.; Ferreira, Hugo A.; Graham, Daniel L.; Freitas, Paulo P.

    2005-01-01

    Magnetic sensors based on the planar Hall effect of exchanged-biased permalloy have been fabricated and characterized. It is demonstrated that the sensors are feasible for detecting just a few commercial 2.0 μm magnetic beads commonly used for bioseparation (Micromer-M, Micromod, Germany) and that the sensor sense current is sufficient to generate a signal from the beads

  11. Active Learning with Monty Hall in a Game Theory Class

    Science.gov (United States)

    Brokaw, Alan J.; Merz, Thomas E.

    2004-01-01

    The authors describe a game that students can play on the first day of a game theory class. The game introduces the 4 essential elements of any game and is designed so that its sequel, also played on the first day of class, has students playing the well-known Monty Hall game, which raises the question: Should you switch doors? By implementing a…

  12. Particle-in-cell simulations of Hall plasma thrusters

    Science.gov (United States)

    Miranda, Rodrigo; Ferreira, Jose Leonardo; Martins, Alexandre

    2016-07-01

    Hall plasma thrusters can be modelled using particle-in-cell (PIC) simulations. In these simulations, the plasma is described by a set of equations which represent a coupled system of charged particles and electromagnetic fields. The fields are computed using a spatial grid (i.e., a discretization in space), whereas the particles can move continuously in space. Briefly, the particle and fields dynamics are computed as follows. First, forces due to electric and magnetic fields are employed to calculate the velocities and positions of particles. Next, the velocities and positions of particles are used to compute the charge and current densities at discrete positions in space. Finally, these densities are used to solve the electromagnetic field equations in the grid, which are interpolated at the position of the particles to obtain the acting forces, and restart this cycle. We will present numerical simulations using software for PIC simulations to study turbulence, wave and instabilities that arise in Hall plasma thrusters. We have sucessfully reproduced a numerical simulation of a SPT-100 Hall thruster using a two-dimensional (2D) model. In addition, we are developing a 2D model of a cylindrical Hall thruster. The results of these simulations will contribute to improve the performance of plasma thrusters to be used in Cubesats satellites currenty in development at the Plasma Laboratory at University of Brasília.

  13. Hall kirjandus võrgustunud maailmas / Anneli Kuiv

    Index Scriptorium Estoniae

    Kuiv, Anneli

    2003-01-01

    1997. aasta määratluse kohaselt on hall kirjandus "kirjandus, mida toodetakse kõikidel tasanditel valitsus- ja teadusasutuste, äri- ja tootmisringkondade poolt nii trükituna kui ka elektroonselt, kuid mis ei ole kirjastustööstuse kontrolli all"

  14. Hall effects on MHD flow past an accelerated plate

    International Nuclear Information System (INIS)

    Soundalgekar, V.M.; Ravi, S.; Hiremath, S.B.

    1980-01-01

    An exact solution of the MHD flow of an incompressible, electrically conducting, viscous fluid past a uniformly accelerated plate is presented. The velocity profiles are shown graphically and the numerical values of axial and transverse components of skin friction are tabulated. At high values of the Hall parameter, ωtau, the velocity is found to be oscillatory near the plate. (author)

  15. new concepts of a modified hall - petch type relationship

    African Journals Online (AJOL)

    NIJOTECH

    Abstract. A modified form of the Hall - Perch equation, where the average grain diameter is replaced by the surface to volume ratio of internal boundaries (Sv), is considered. Working with this model, a flow stress – Sv relationship dominated by geometrically necessary dislocations (GNDs) is derived for the low strain region.

  16. Effect of Hall Current and Finite Larmor Radius Corrections on ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy; Volume 37; Issue 3. Effect of Hall Current and Finite Larmor Radius Corrections on Thermal Instability of Radiative Plasma for Star Formation in Interstellar Medium (ISM). Sachin Kaothekar. Research Article Volume 37 Issue 3 September 2016 Article ID 23 ...

  17. Energy efficient heating and ventilation of large halls

    CERN Document Server

    Hojer, Ondrej; Kabele, Karel; Kotrbaty, Miroslav; Sommer, Klaus; Petras, Dusan

    2011-01-01

    This guidebook is focused on modern methods for design, control and operation of energy efficient heating systems in large spaces and industrial halls. The book deals with thermal comfort, light and dark gas radiant heaters, panel radiant heating, floor heating and industrial air heating systems. Various heating systems are illustrated with case studies. Design principles, methods and modeling tools are presented for various systems.

  18. Composite fermions a unified view of the quantum Hall regime

    CERN Document Server

    1998-01-01

    One of the most exciting recent developments to have emerged from the quantum Hall effect is the subject of composite fermions. This important volume gives a self-contained, comprehensive description of the subject, including fundamentals, more advanced theoretical work, and results from experimental observations of composite fermions.

  19. The Marketing of Residence Halls: A Question of Positioning.

    Science.gov (United States)

    Parker, R. Stephen; And Others

    1996-01-01

    A survey of 343 college residence hall directors revealed percentages of private and public institutions offering different amenities, main selling points in promotional brochures, and the most common resident complaints. Results were compared with those of a resident survey concerning the importance of various housing attributes. Implications for…

  20. Virginia Tech's College Of Natural Resources Dedicates Cheatham Hall Expansion

    OpenAIRE

    Davis, Lynn

    2003-01-01

    Thanks to funding by private donors, Alyce Cheatham and her family of Portland, Oregon, Virginia Tech's College of Natural Resources will dedicate a much-needed, three-story addition to its current Cheatham Hall on Wednesday, March 19, at 2:30 p.m.

  1. Tondiraba jäähall = Tondiraba ice arena

    Index Scriptorium Estoniae

    2015-01-01

    Tondiraba jäähall Tallinnas Varraku tänav 14, valminud 2014. Arhitektid Ott Kadarik, Mihkel Tüür, Kadri Tamme (Kadarik Tüür Arhitektid OÜ), insener Paavo Pikand. Eesti Kultuurkapitali Arhitektuuri sihtkapitali aastapreemia 2014

  2. Field theory of anyons and the fractional quantum Hall effect

    International Nuclear Information System (INIS)

    Viefers, S.F.

    1997-11-01

    The thesis is devoted to a theoretical study of anyons, i.e. particles with fractional statistics moving in two space dimensions, and the quantum Hall effect. The latter constitutes the only known experimental realization of anyons in that the quasiparticle excitations in the fractional quantum Hall system are believed to obey fractional statistics. First, the properties of ideal quantum gases in two dimensions and in particular the equation of state of the free anyons gas are discussed. Then, a field theory formulation of anyons in a strong magnetic field is presented and later extended to a system with several species of anyons. The relation of this model to fractional exclusion statistics, i.e. intermediate statistics introduced by a generalization of the Pauli principle, and to the low-energy excitations at the edge of the quantum Hall system is discussed. Finally, the Chern-Simons-Landau-Ginzburg theory of the fractional quantum Hall effect is studied, mainly focusing on edge effects; both the ground state and the low-energy edge excitations are examined in the simple one-component model and in an extended model which includes spin effects

  3. Involving Students in Residence Halls in Hong Kong

    Science.gov (United States)

    Ting, S. Raymond; Chan, Rebecca; Lee, Esther

    2016-01-01

    This article reports a study based on A. W. Astin's (1984) involvement theory applied in residence halls at a public university in Hong Kong, China. The resident students who were involved as participants or student leaders in this study were found to be better developed in terms of leadership, career development, multicultural experience,…

  4. Magnus force on quantum Hall skyrmions and vortices

    International Nuclear Information System (INIS)

    Dhar, S.; Basu, B.; Bandyopadhyay, P.

    2003-01-01

    We have discussed here the Magnus force acting on the vortices and skyrmions in the quantum Hall systems. We have found that it is generated by the chirality of the system which is associated with the Berry phase and is same for both the cases

  5. Single particle detection: Phase control in submicron Hall sensors

    International Nuclear Information System (INIS)

    Di Michele, Lorenzo; Shelly, Connor; Gallop, John; Kazakova, Olga

    2010-01-01

    We present a phase-sensitive ac-dc Hall magnetometry method which allows a clear and reliable separation of real and parasitic magnetic signals of a very small magnitude. High-sensitivity semiconductor-based Hall crosses are generally accepted as a preferential solution for non-invasive detection of superparamagnetic nanobeads used in molecular biology, nanomedicine, and nanochemistry. However, detection of such small beads is often hindered by inductive pick-up and other spurious signals. The present work demonstrates an unambiguous experimental route for detection of small magnetic moments and provides a simple theoretical background for it. The reliability of the method has been tested for a variety of InSb Hall sensors in the range 600 nm-5 μm. Complete characterization of empty devices, involving Hall coefficients and noise measurements, has been performed and detection of a single FePt bead with diameter of 140 nm and magnetic moment of μ≅10 8 μ B has been achieved with a 600 nm-wide sensor.

  6. Low-frequency noise in planar Hall effect bridge sensors

    DEFF Research Database (Denmark)

    Persson, Anders; Bejhedb, R.S.; Bejhed, R.S.

    2011-01-01

    The low-frequency characteristics of planar Hall effect bridge sensors are investigated as function of the sensor bias current and the applied magnetic field. The noise spectra reveal a Johnson-like spectrum at high frequencies, and a 1/f-like excess noise spectrum at lower frequencies, with a kn...

  7. Quantum Hall Effect: proposed multi-electron tunneling experiment

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.

    1985-11-01

    Here we propose a tunneling experiment for the fractional and Integral Quantum Hall Effect. It may demonstrate multi-electron tunneling and may provide information about the nature of the macroscopic quantum states of 2D electronic liquid or solid. (author)

  8. Observation of the fractional quantum Hall effect in graphene.

    Science.gov (United States)

    Bolotin, Kirill I; Ghahari, Fereshte; Shulman, Michael D; Stormer, Horst L; Kim, Philip

    2009-11-12

    When electrons are confined in two dimensions and subject to strong magnetic fields, the Coulomb interactions between them can become very strong, leading to the formation of correlated states of matter, such as the fractional quantum Hall liquid. In this strong quantum regime, electrons and magnetic flux quanta bind to form complex composite quasiparticles with fractional electronic charge; these are manifest in transport measurements of the Hall conductivity as rational fractions of the elementary conductance quantum. The experimental discovery of an anomalous integer quantum Hall effect in graphene has enabled the study of a correlated two-dimensional electronic system, in which the interacting electrons behave like massless chiral fermions. However, owing to the prevailing disorder, graphene has so far exhibited only weak signatures of correlated electron phenomena, despite intense experimental and theoretical efforts. Here we report the observation of the fractional quantum Hall effect in ultraclean, suspended graphene. In addition, we show that at low carrier density graphene becomes an insulator with a magnetic-field-tunable energy gap. These newly discovered quantum states offer the opportunity to study correlated Dirac fermions in graphene in the presence of large magnetic fields.

  9. Mechanism of plateau formation in the fractional quantum Hall effect

    International Nuclear Information System (INIS)

    Bruus, H.; Hansen, O.P.; Hansen, E.B.

    1988-01-01

    Laughlin's fractionally charged quasi-holes and quasi-electrons are assumed to be pinned, and to be subject to a force j vectorxΦ 0 vector from the transport current. A force balance argument then explains the existence of Hall plateaus. (orig.)

  10. Planar Hall effect sensor for magnetic micro- and nanobead detection

    DEFF Research Database (Denmark)

    Ejsing, Louise Wellendorph; Hansen, Mikkel Fougt; Menon, Aric Kumaran

    2004-01-01

    Magnetic bead sensors based on the planar Hall effect in thin films of exchange-biased permalloy have been fabricated and characterized. Typical sensitivities are 3 muV/Oe mA. The sensor response to an applied magnetic field has been measured without and with coatings of commercially available 2 ...

  11. Mini array of quantum Hall devices based on epitaxial graphene

    International Nuclear Information System (INIS)

    Novikov, S.; Lebedeva, N.; Hämäläinen, J.; Iisakka, I.; Immonen, P.; Manninen, A. J.; Satrapinski, A.

    2016-01-01

    Series connection of four quantum Hall effect (QHE) devices based on epitaxial graphene films was studied for realization of a quantum resistance standard with an up-scaled value. The tested devices showed quantum Hall plateaux R H,2 at a filling factor v = 2 starting from a relatively low magnetic field (between 4 T and 5 T) when the temperature was 1.5 K. The precision measurements of quantized Hall resistance of four QHE devices connected by triple series connections and external bonding wires were done at B = 7 T and T = 1.5 K using a commercial precision resistance bridge with 50 μA current through the QHE device. The results showed that the deviation of the quantized Hall resistance of the series connection of four graphene-based QHE devices from the expected value of 4×R H,2  = 2 h/e 2 was smaller than the relative standard uncertainty of the measurement (<1 × 10 −7 ) limited by the used resistance bridge.

  12. Hall Thruster Thermal Modeling and Test Data Correlation

    Science.gov (United States)

    Myers, James; Kamhawi, Hani; Yim, John; Clayman, Lauren

    2016-01-01

    The life of Hall Effect thrusters are primarily limited by plasma erosion and thermal related failures. NASA Glenn Research Center (GRC) in cooperation with the Jet Propulsion Laboratory (JPL) have recently completed development of a Hall thruster with specific emphasis to mitigate these limitations. Extending the operational life of Hall thursters makes them more suitable for some of NASA's longer duration interplanetary missions. This paper documents the thermal model development, refinement and correlation of results with thruster test data. Correlation was achieved by minimizing uncertainties in model input and recognizing the relevant parameters for effective model tuning. Throughout the thruster design phase the model was used to evaluate design options and systematically reduce component temperatures. Hall thrusters are inherently complex assemblies of high temperature components relying on internal conduction and external radiation for heat dispersion and rejection. System solutions are necessary in most cases to fully assess the benefits and/or consequences of any potential design change. Thermal model correlation is critical since thruster operational parameters can push some components/materials beyond their temperature limits. This thruster incorporates a state-of-the-art magnetic shielding system to reduce plasma erosion and to a lesser extend power/heat deposition. Additionally a comprehensive thermal design strategy was employed to reduce temperatures of critical thruster components (primarily the magnet coils and the discharge channel). Long term wear testing is currently underway to assess the effectiveness of these systems and consequently thruster longevity.

  13. NASA HERMeS Hall Thruster Electrical Configuration Characterization

    Science.gov (United States)

    Peterson, Peter; Kamhawi, Hani; Huang, Wensheng; Yim, John; Herman, Daniel; Williams, George; Gilland, James; Hofer, Richard

    2016-01-01

    NASAs Hall Effect Rocket with Magnetic Shielding (HERMeS) 12.5 kW Technology Demonstration Unit-1 (TDU-1) Hall thruster has been the subject of extensive technology maturation in preparation for development into a flight ready propulsion system. Part of the technology maturation was to test the TDU-1 thruster in several ground based electrical configurations to assess the thruster robustness and suitability to successful in-space operation. The ground based electrical configuration testing has recently been demonstrated as an important step in understanding and assessing how a Hall thruster may operate differently in space compared to ground based testing, and to determine the best configuration to conduct development and qualification testing. This presentation will cover the electrical configuration testing of the TDU-1 HERMeS Hall thruster in NASA Glenn Research Centers Vacuum Facility 5. The three electrical configurations examined are the thruster body tied to facility ground, thruster floating, and finally the thruster body electrically tied to cathode common. The TDU-1 HERMeS was configured with two different exit plane boundary conditions, dielectric and conducting, to examine the influence on the electrical configuration characterization.

  14. An evaluation of krypton propellant in Hall thrusters

    Science.gov (United States)

    Linnell, Jesse Allen

    Due to its high specific impulse and low price, krypton has long sparked interest as an alternate Hall thruster propellant. Unfortunately at the moment, krypton's relatively poor performance precludes it as a legitimate option. This thesis presents a detailed investigation into krypton operation in Hall thrusters. These findings suggest that the performance gap can be decreased to 4% and krypton can finally become a realistic propellant option. Although krypton has demonstrated superior specific impulse, the xenon-krypton absolute efficiency gap ranges between 2 and 15%. A phenomenological performance model indicates that the main contributors to the efficiency gap are propellant utilization and beam divergence. Propellant utilization and beam divergence have relative efficiency deficits of 5 and 8%, respectively. A detailed characterization of internal phenomena is conducted to better understand the xenon-krypton efficiency gap. Krypton's large beam divergence is found to be related to a defocusing equipotential structure and a weaker magnetic field topology. Ionization processes are shown to be linked to the Hall current, the magnetic mirror topology, and the perpendicular gradient of the magnetic field. Several thruster design and operational suggestions are made to optimize krypton efficiency. Krypton performance is optimized for discharge voltages above 500 V and flow rates corresponding to an a greater than 0.015 mg/(mm-s), where alpha is a function of flow rate and discharge channel dimensions (alpha = m˙alphab/Ach). Performance can be further improved by increasing channel length or decreasing channel width for a given flow rate. Also, several magnetic field design suggestions are made to enhance ionization and beam focusing. Several findings are presented that improve the understanding of general Hall thruster physics. Excellent agreement is shown between equipotential lines and magnetic field lines. The trim coil is shown to enhance beam focusing

  15. Quantum Hall conductivity in a Landau type model with a realistic geometry

    International Nuclear Information System (INIS)

    Chandelier, F.; Georgelin, Y.; Masson, T.; Wallet, J.-C.

    2003-01-01

    In this paper, we revisit some quantum mechanical aspects related to the quantum Hall effect. We consider a Landau type model, paying a special attention to the experimental and geometrical features of quantum Hall experiments. The resulting formalism is then used to compute explicitly the Hall conductivity from a Kubo formula

  16. Current Percolation in Medium with Boundaries under Quantum Hall Effect Conditions

    Directory of Open Access Journals (Sweden)

    M. U. Malakeeva

    2012-01-01

    Full Text Available The current percolation has been considered in the medium with boundaries under quantum Hall effect conditions. It has been shown that in that case the effective Hall conductivity has a nonzero value due to percolation of the Hall current through the finite number of singular points (in our model these are corners at the phase joints.

  17. Experimental and theoretical studies of cylindrical Hall thrusters

    International Nuclear Information System (INIS)

    Smirnov, Artem; Raitses, Yegeny; Fisch, Nathaniel J.

    2007-01-01

    The Hall thruster is a mature electric propulsion device that holds considerable promise in terms of the propellant saving potential. The annular design of the conventional Hall thruster, however, does not naturally scale to low power. The efficiency tends to be lower and the lifetime issues are more aggravated. Cylindrical geometry Hall thrusters have lower surface-to-volume ratio than conventional thrusters and, thus, seem to be more promising for scaling down. The cylindrical Hall thruster (CHT) is fundamentally different from the conventional design in the way the electrons are confined and the ion space charge is neutralized. The performances of both the large (9-cm channel diameter, 600-1000 W) and miniaturized (2.6-cm channel diameter, 50-300 W) CHTs are comparable with those of the state-of-the-art conventional (annular) design Hall thrusters of similar sizes. A comprehensive experimental and theoretical study of the CHT physics has been conducted, addressing the questions of electron cross-field transport, propellant ionization, plasma-wall interaction, and formation of the electron distribution function. Probe measurements in the harsh plasma environment of the microthruster were performed. Several interesting effects, such as the unusually high ionization efficiency and enhanced electron transport, were observed. Kinetic simulations suggest the existence of the strong fluctuation-enhanced electron diffusion and predict the non-Maxwellian shape of the electron distribution function. Through the acquired understanding of the new physics, ways for further optimization of this means for low-power space propulsion are suggested. Substantial flexibility in the magnetic field configuration of the CHT is the key tool in achieving the high-efficiency operation

  18. Upper respiratory tract (image)

    Science.gov (United States)

    The major passages and structures of the upper respiratory tract include the nose or nostrils, nasal cavity, mouth, throat (pharynx), and voice box (larynx). The respiratory system is lined with a mucous membrane that ...

  19. ACA Federal Upper Limits

    Data.gov (United States)

    U.S. Department of Health & Human Services — Affordable Care Act Federal Upper Limits (FUL) based on the weighted average of the most recently reported monthly average manufacturer price (AMP) for...

  20. Upper gastrointestinal bleeding.

    Science.gov (United States)

    Feinman, Marcie; Haut, Elliott R

    2014-02-01

    Upper gastrointestinal (GI) bleeding remains a commonly encountered diagnosis for acute care surgeons. Initial stabilization and resuscitation of patients is imperative. Stable patients can have initiation of medical therapy and localization of the bleeding, whereas persistently unstable patients require emergent endoscopic or operative intervention. Minimally invasive techniques have surpassed surgery as the treatment of choice for most upper GI bleeding. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Flood-inundation maps for the Saddle River in Ho-Ho-Kus Borough, the Village of Ridgewood, and Paramus Borough, New Jersey, 2013

    Science.gov (United States)

    Watson, Kara M.; Niemoczynski, Michal J.

    2014-01-01

    Digital flood-inundation maps for a 5.4-mile reach of the Saddle River in New Jersey from Hollywood Avenue in Ho-Ho-Kus Borough downstream through the Village of Ridgewood and Paramus Borough to the confluence with Hohokus Brook in the Village of Ridgewood were created by the U.S. Geological Survey (USGS) in cooperation with the New Jersey Department of Environmental Protection (NJDEP). The inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage on the Saddle River at Ridgewood, New Jersey (station 01390500). Current conditions for estimating near real-time areas of inundation using USGS streamgage information may be obtained on the Internet at http://waterdata.usgs.gov/nwis/uv?site_no=01390500 or at the National Weather Services (NWS) Advanced Hydrologic Prediction Service (AHPS) at http://water.weather.gov/ahps2/hydrograph.php?wfo=okx&gage=rwdn4. In this study, flood profiles were computed for the stream reach by means of a one-dimensional step-backwater model. The model was calibrated by using the most current stage-discharge relation (March 11, 2011) at the USGS streamgage 01390500, Saddle River at Ridgewood, New Jersey. The hydraulic model was then used to compute 10 water-surface profiles for flood stages at 1-foot (ft) intervals referenced to the streamgage datum, North American Vertical Datum of 1988 (NAVD 88), and ranging from 5 ft, the NWS “action and minor flood stage”, to 14 ft, which is the maximum extent of the stage-discharge rating and 0.6 ft higher than the highest recorded water level at the streamgage. The simulated water-surface profiles were then combined with a geographic information system 3-meter (9.84-ft) digital elevation model derived from Light Detection and Ranging (lidar) data in order to delineate the area flooded

  2. Upper GI Bleeding in Children

    Science.gov (United States)

    Upper GI Bleeding in Children What is upper GI Bleeding? Irritation and ulcers of the lining of the esophagus, stomach or duodenum can result in upper GI bleeding. When this occurs the child may vomit blood ...

  3. Power, Performance, and Perception (P3): Integrating Usability Metrics and Technology Acceptance Determinants to Validate a New Model for Predicting System Usage

    Science.gov (United States)

    1999-12-01

    Ergonomie Requirements for Office Work with Visual Display Terminals: Part 11- Guidance on Usability (Smith, 1996:69-70). Measures of effectiveness...Wesley, 1998. Smith, Wanda, J. ISO and ANSI Ergonomie Standards for Computer Products. Upper Saddle River, NJ: Prentice Hall, 1996. Szajna, Bemadette

  4. A Perfectly Matched Layer for Peridynamics in Two Dimensions

    Science.gov (United States)

    2013-04-01

    KIM Seoul National University, Republic of Korea Z. MROZ Academy of Science, Poland D. PAMPLONA Universidade Católica do Rio de Janeiro , Brazil M. B...applications, Prentice-Hall, Upper Saddle River , NJ, 1996. [Silling 2000] S. A. Silling, “Reformulation of elasticity theory for discontinuities and long

  5. A Framework for Seamless Interoperation of Heterogeneous Distributed Software Components

    Science.gov (United States)

    2005-05-01

    have access control policy This paper proposes that access control patterns (in that is defined by privacy and confidentiality legislation the form of...2003, Prentice Hall, Upper Saddle River, New Jersey 07458 [5] Dhbingra, V., "Business-to-Business Ecommerce ," http://proiects.bus.lsu.edu/independent

  6. An Artificial Neural Network-Based Decision-Support System for Integrated Network Security

    Science.gov (United States)

    2014-09-01

    inbreeding, hybridization, or mutation, a concept introduced by Charles Darwin in 1809 (Quammen, 2008). Within the field of CAS, emergent behavior...Enterprise. Upper Saddle River, NJ, USA: Prentice Hall. Quammen, D. (2008). Charles Darwin : On the Origin of Species The Illustrated Edition. New

  7. Applying the Art of Systems and Organizational Architecting in Order to Implement Operational Design into Marine Corps Planning Doctrine

    Science.gov (United States)

    2011-09-01

    worldview of all stakeholders possibly involved in the operational system at the present time and in the future ( Checkland & Poulter, 2006). In...Blanchard, B.S., & Fabrycky, W.J. (1998). Systems engineering and analysis, 4th ed. Upper Saddle River, NJ: Prentice Hall. Checkland , P. & Poulter, J

  8. Joint Robotics Program

    Science.gov (United States)

    2008-04-23

    Kotler , P.M. (1997). Marketing management: Analysis, planning, implementation, and control. Upper Saddle River, NJ: Prentice Hall...needed to provide needed items. Production needed to be stable so suppliers could more easily meet demand ( Kotler , 1997, pp. 214-215). The Robotics

  9. Reorganizing Geographic Combatant Command Headquarters for Joint Force 2020

    Science.gov (United States)

    2013-05-01

    Keegan, Global Marketing Management, 7 th Ed. (Upper Saddle River, NJ: Prentice Hall, 2002), 523. 30 Hellriegel, Jackson, and Slocum, Management...bring together mission, resources, and time. 31 Keegan, Global Marketing Management, 520. 20... Marketing Management, 523. 34 Keegan, Global Marketing Management, 523. 22 strategic alliance is an “agreement for cooperation among two or more

  10. Fission along the mass asymmetry coordinate: an experimental evaluation of the conditional saddle masses and of the Businaro-Gallone point

    International Nuclear Information System (INIS)

    Moretto, L.G.; McMahan, M.A.; Sobotka, L.G.; Wozniak, G.J.

    1984-12-01

    The importance of empirically determining the ridge line of conditional saddle points is discussed in view of the recent liquid drop model refinements, like diffuseness and finite range. Two series of experiments are presented. The first series involves the complex fragment emission from compound nuclei resulting from the 3 He + Ag reaction. Kinetic energy distributions and excitation functions are shown, and the conditional barriers are obtained over a range of atomic numbers. In the second series, reverse kinematic reactions like Ge, Nb, La + Be, C are studied. The fragments emitted cover the entire Z range, from Z = 1 to symmetric splitting. Their origin from a full momentum transfer intermediate is shown. From the complete charge distributions it is possible to conclude that the Businaro-Gallone transition is observed. 15 references

  11. Saddle-nose and bilateral cauliflower ear deformities with pyoderma gangrenosum-like ulcers, cavitary pulmonary lesions, digital gangrene and pulselessness in a young female.

    Science.gov (United States)

    Subhadarshani, Sweta; Gupta, Vishal; Chahal, Anurag; Verma, Kaushal K

    2017-06-15

    We report a young female who presented with saddle-nose and bilateral cauliflower ear deformities along with pyoderma gangrenosum-like ulcers, digital gangrene and pulselessness. Subsequently, she was found to have bilateral conductive hearing loss, a corneal opacity, mild aortic regurgitation and radiological evidence of cavitary changes in lungs and aortoarteritis. Our patient had a constellation of symptoms which posed a diagnostic challenge. Finally, a diagnosis of relapsing polychondritis with several unusual features was made. Overlap with Takayasu's arteritis and granulomatosis with polyangitis, which has been reported rarely in the literature, cannot be excluded. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  12. A Monolithic CMOS Magnetic Hall Sensor with High Sensitivity and Linearity Characteristics.

    Science.gov (United States)

    Huang, Haiyun; Wang, Dejun; Xu, Yue

    2015-10-27

    This paper presents a fully integrated linear Hall sensor by means of 0.8 μm high voltage complementary metal-oxide semiconductor (CMOS) technology. This monolithic Hall sensor chip features a highly sensitive horizontal switched Hall plate and an efficient signal conditioner using dynamic offset cancellation technique. An improved cross-like Hall plate achieves high magnetic sensitivity and low offset. A new spinning current modulator stabilizes the quiescent output voltage and improves the reliability of the signal conditioner. The tested results show that at the 5 V supply voltage, the maximum Hall output voltage of the monolithic Hall sensor microsystem, is up to ±2.1 V and the linearity of Hall output voltage is higher than 99% in the magnetic flux density range from ±5 mT to ±175 mT. The output equivalent residual offset is 0.48 mT and the static power consumption is 20 mW.

  13. Stress concentration factors at saddle and crown positions on the central brace of two-planar welded CHS DKT-connections

    Science.gov (United States)

    Ahmadi, Hamid; Lotfollahi-Yaghin, Mohammad Ali; Aminfar, Mohammad H.

    2012-03-01

    A set of parametric stress analyses was carried out for two-planar tubular DKT-joints under different axial loading conditions. The analysis results were used to present general remarks on the effects of the geometrical parameters on stress concentration factors (SCFs) at the inner saddle, outer saddle, and crown positions on the central brace. Based on results of finite element (FE) analysis and through nonlinear regression analysis, a new set of SCF parametric equations was established for fatigue design purposes. An assessment study of equations was conducted against the experimental data and original SCF database. The satisfaction of acceptance criteria proposed by the UK Department of Energy (UK DoE) was also checked. Results of parametric study showed that highly remarkable differences exist between the SCF values in a multi-planar DKT-joint and the corresponding SCFs in an equivalent uni-planar KT-joint having the same geometrical properties. It can be clearly concluded from this observation that using the equations proposed for uni-planar KT-connections to compute the SCFs in multi-planar DKT-joints will lead to either considerably under-predicting or over-predicting results. Hence, it is necessary to develop SCF formulae specially designed for multi-planar DKT-joints. Good results of equation assessment according to UK DoE acceptance criteria, high values of correlation coefficients, and the satisfactory agreement between the predictions of the proposed equations and the experimental data guarantee the accuracy of the equations. Therefore, the developed equations can be reliably used for fatigue design of offshore structures.

  14. Hydrothermal dolomitization of the Bekhme formation (Upper Cretaceous), Zagros Basin, Kurdistan Region of Iraq: Record of oil migration and degradation

    Science.gov (United States)

    Mansurbeg, Howri; Morad, Daniel; Othman, Rushdy; Morad, Sadoon; Ceriani, Andrea; Al-Aasm, Ihsan; Kolo, Kamal; Spirov, Pavel; Proust, Jean Noel; Preat, Alain; Koyi, Hemin

    2016-07-01

    The common presence of oil seepages in dolostones is widespread in Cretaceous carbonate successions of the Kurdistan Region of Iraq. This integrated field, petrographic, chemical, stable C, O and Sr isotopes, and fluid inclusion study aims to link dolomitization to the origin and geochemical evolution of fluids and oil migration in the Upper Cretaceous Bekhme carbonates. Flux of hot basinal (hydrothermal) brines, which is suggested to have occurred during the Zagros Orogeny, resulted in dolomitization and cementation of vugs and fractures by coarse-crystalline saddle dolomite, equant calcite and anhydrite. The saddle dolomite and host dolostones have similar stable isotopic composition and formed prior to oil migration from hot (81-115 °C) basinal NaCl-MgCl2-H2O brines with salinities of 18-22 wt.% NaCl eq. The equant calcite cement, which surrounds and hence postdates saddle dolomite, has precipitated during oil migration from cooler (60-110 °C) NaCl-CaCl2-H2O brines (14-18 wt.% NaCl eq). The yellowish fluorescence color of oil inclusions in the equant calcite indicates that the oil had API gravity of 15-25° composition, which is lighter than present-day oil in the reservoirs (API of 10-17°). This difference in oil composition is attributed to oil degradation by the flux of meteoric water, which is evidenced by the low δ13C values (- 8.5‰ to - 3.9‰ VPDB) as well as by nil salinity and low temperature in fluid inclusions of late columnar calcite cement. This study demonstrates that linking fluid flux history and related diagenesis to the tectonic evolution of the basin provides important clues to the timing of oil migration, degradation and reservoir evolution.

  15. Right upper quadrant pain

    International Nuclear Information System (INIS)

    Ralls, P.W.; Colletti, P.M.; Boswell, W.D. Jr.; Halls, J.M.

    1984-01-01

    Historically, assessment of acute right upper quadrant abdominal pain has been a considerable clinical challenge. While clinical findings and laboratory data frequently narrow the differential diagnosis, symptom overlap generally precludes definitive diagnosis among the various diseases causing acute right upper quadrant pain. Fortunately, the advent of newer diagnostic imaging modalities has greatly improved the rapidity and reliability of diagnosis in these patients. An additional challenge to the physician, with increased awareness of the importance of cost effectiveness in medicine, is to select appropriate diagnostic schema that rapidly establish accurate diagnoses in the most economical fashion possible. The dual goals of this discussion are to assess not only the accuracy of techniques used to evaluate patients with acute right upper quadrant pain, but also to seek out cost-effective, coordinated imaging techniques to achieve this goal

  16. Audience noise in concert halls during musical performances

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Marie, Pierre; Brunskog, Jonas

    2012-01-01

    functions of the sound pressure levels were obtained in octave bands, which were fitted with three Gaussian distribution curves. The Gaussian distribution curve with the lowest mean value corresponds to a mixture of the technical background noise and audience generated noise, which is named the mixed...... background noise. Finally, the audience noise distribution is extracted by energy subtraction of the technical background noise levels measured in an empty condition from the mixed background noise levels. As a single index, L-90 of the audience noise distribution is named the audience noise level. Empirical...... prediction models were made using the four orchestra concert halls, revealing that the audience noise level is significantly correlated with the technical background noise level. It is therefore concluded that a relaxation of the current background noise recommendations for concert halls is not recommended...

  17. Audience noise in concert halls during musical performances

    DEFF Research Database (Denmark)

    Marie, Pierre; Jeong, Cheol-Ho; Brunskog, Jonas

    2012-01-01

    functions of the sound pressure levels were obtained in octave bands, which were fitted with three Gaussian distribution curves. The Gaussian distribution curve with the lowest mean value corresponds to a mixture of the technical background noise and audience generated noise, which is named the mixed...... background noise. Finally, the audience noise distribution is extracted by energy subtraction of the technical background noise levels measured in an empty condition from the mixed background noise levels. As a single index, L90 of the audience noise distribution is named the audience noise level. Empirical...... prediction models were made using the four orchestra concert halls, revealing that the audience noise level is significantly correlated with the technical background noise level. It is therefore concluded that a relaxation of the current background noise recommendations for concert halls is not recommended....

  18. Precise quantization of anomalous Hall effect near zero magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Bestwick, A. J. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Fox, E. J. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Kou, Xufeng [Univ. of California, Los Angeles, CA (United States); Pan, Lei [Univ. of California, Los Angeles, CA (United States); Wang, Kang L. [Univ. of California, Los Angeles, CA (United States); Goldhaber-Gordon, D. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-05-04

    In this study, we report a nearly ideal quantum anomalous Hall effect in a three-dimensional topological insulator thin film with ferromagnetic doping. Near zero applied magnetic field we measure exact quantization in the Hall resistance to within a part per 10,000 and a longitudinal resistivity under 1 Ω per square, with chiral edge transport explicitly confirmed by nonlocal measurements. Deviations from this behavior are found to be caused by thermally activated carriers, as indicated by an Arrhenius law temperature dependence. Using the deviations as a thermometer, we demonstrate an unexpected magnetocaloric effect and use it to reach near-perfect quantization by cooling the sample below the dilution refrigerator base temperature in a process approximating adiabatic demagnetization refrigeration.

  19. Modeling of the near field plume of a Hall thruster

    International Nuclear Information System (INIS)

    Boyd, Iain D.; Yim, John T.

    2004-01-01

    In this study, a detailed numerical model is developed to simulate the xenon plasma near-field plume from a Hall thruster. The model uses a detailed fluid model to describe the electrons and a particle-based kinetic approach is used to model the heavy xenon ions and atoms. The detailed model is applied to compute the near field plume of a small, 200 W Hall thruster. Results from the detailed model are compared with the standard modeling approach that employs the Boltzmann model. The usefulness of the model detailed is assessed through direct comparisons with a number of different measured data sets. The comparisons illustrate that the detailed model accurately predicts a number of features of the measured data not captured by the simpler Boltzmann approach

  20. Multi-region relaxed Hall magnetohydrodynamics with flow

    Energy Technology Data Exchange (ETDEWEB)

    Lingam, Manasvi, E-mail: mlingam@princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States); Abdelhamid, Hamdi M., E-mail: hamdi@ppl.k.u-tokyo.ac.jp [Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Physics Department, Faculty of Science, Mansoura University, Mansoura 35516 (Egypt); Hudson, Stuart R., E-mail: shudson@pppl.gov [Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543 (United States)

    2016-08-15

    The recent formulations of multi-region relaxed magnetohydrodynamics (MRxMHD) have generalized the famous Woltjer-Taylor states by incorporating a collection of “ideal barriers” that prevent global relaxation and flow. In this paper, we generalize MRxMHD with flow to include Hall effects, and thereby obtain the partially relaxed counterparts of the famous double Beltrami states as a special subset. The physical and mathematical consequences arising from the introduction of the Hall term are also presented. We demonstrate that our results (in the ideal MHD limit) constitute an important subset of ideal MHD equilibria, and we compare our approach against other variational principles proposed for deriving the partially relaxed states.