Sample records for blackfriars hall oxford

  1. Radiological characterization survey results for Gaskill Hall, Miami University, Oxford, Ohio (OXO015)

    International Nuclear Information System (INIS)

    Kleinhans, K.R.; Murray, M.E.; Carrier, R.F.


    Between October 1952 and February 1957, National Lead of Ohio (NLO), a primary contractor for the Atomic Energy Commission (AEC), subcontracted certain uranium machining operations to Alba Craft Laboratory, Incorporated, located at 10-14 West Rose Avenue, Oxford, Ohio. In 1992, personnel from Oak Ridge National Laboratory (ORNL) confirmed the presence of residual radioactive materials from the AEC-related operations in and around the facility in amounts exceeding the applicable Department of Energy (DOE) guidelines. Although the amount of uranium found on the property posed little health hazard if left undisturbed, the levels were sufficient to require remediation to bring radiological conditions into compliance with current guidelines, thus ensuring that the public and the environment are protected. Because it was suspected that uranium may have been used in the past in the immediate vicinity of Alba Craft in a Miami University building a team from ORNL, performed a radiological characterization survey of that structure in January 1994. The survey was conducted at the request of DOE as a precautionary measure to ensure that no radioactive residuals were present at levels exceeding guidelines. The survey included the determination of directly measured radiation levels and the collection of smear samples to detect possible removable alpha and beta-gamma activity levels, and comparison of these data to the guidelines. Results of the survey showed that all measurements were below the applicable guideline limits set by DOE

  2. Enterprising future for Oxford


    George Smith


    The aims of the Department of Materials at Oxford University stretch from cutting edge research to encouraging knowledge of materials at school level. At a time when some traditional scientific disciplines are seeing student numbers fall, materials science — and Oxford Materials — is gaining a higher profile than ever before.

  3. New Oxford style manual

    CERN Document Server


    The New Oxford Style Manual brings together two essential reference works in a single volume: New Hart's Rules and the New Oxford Dictionary for Writers and Editors. New Hart's Rules, Oxford's definitive guide to style, consists of 20 chapters that provide authoritative and expert advice on how to prepare copy for publication. Topics covered include how to use italic, roman, and other type treatments, numbers and dates, law and legal references, illustrations, notes and references, and bibliographies. The guidelines are complemented by the New Oxford Dictionary for Writers and Editors, which features 25,000 alphabetically arranged entries giving authoritative advice on those words and names which raise questions time and time again because of spelling, capitalization, hyphenation, or cultural and historical context. Entries give full coverage of recommended spellings, variant forms, confusable words, hyphenation, capitalization, foreign and specialist terms, proper names, and abbreviations. The dictionary a...

  4. Oxford exploding spires. (United States)

    Guest, I


    Barbara Ward in her keynote address to the Conference on Exploding Cities, held in Oxford England, made the point that the current problems of the cities can only worsen as the world's population doubles by the year 2000 and the worst hit will be the cities of the developing nations. Between 1950 and 2000 urban populations will rise from 500 million to 1000 million, but the equivalent rise in the 3rd world will be from 500 million to 2200 million. The Conference was more successful in identifying the problems and their causes than in proposing solutions. The inadequacy of urban transport was emphasized repeatedly. Crime emerges as another urban headache. Pollution was another popular theme, and shanties were thoroughly examined. Positive proposals too often took the form of self-evident truths. In all cases the message is clear: the 1st prerequisite to urban planning is central control and, if necessary, public ownership of land. A succession of speakers advocated more self-help for the communities which have emerged on the periphery of so many urban centers. Elizabeth Jelin, from Buenos Aires, argued that these communities -- and shanty towns are the most obvious manifestation -- should no longer be viewed as marginal. They perform essential services, especially in terms of employment, and cannot be moved without severe disruption. Self-help was the beacon held up to delegates, despite the warnings that it would lead to complacency on the part of authorities.

  5. Hall A (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...

  6. Hall C (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...

  7. The Port Oxford meteorite hoax (United States)

    Plotkin, H.


    An account is given of the solving of a longstanding mystery concerning the true origin of pallasite (stony-iron) meteorite fragments which John Evans claimed to have taken from a 10-ton object in the vicinity of the Rogue River mountains, near Port Oxford, Oregon. Elemental analyses have established that the fragments were taken from the Imilac/Ilimaes meteorite field in the Atacama Desert of Chile.

  8. Experimental halls workshop summary

    International Nuclear Information System (INIS)

    Thorndike, A.


    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

  9. Review of the Oxford Cryocooler

    International Nuclear Information System (INIS)

    Davey, G.


    The Oxford Cryocooler incorporates a linear drive compressor operating close to resonance. All dynamic seals are noncontacting clearance seals maintained by mounting the piston and displacer on mechanical suspension systems with infinite fatigue life. The displacer is pneumatically driven but controlled by a miniature linear motor. The cooler is therefore nonwearing and performance can be maintained even in adverse environments by servo control of piston and displacer strokes and relative phase. Split and integral, single- and two-stage coolers have been produced with operating temperatures between 30 K and 200 K, refrigeration powers between 50 mW and several watts and capable of operating in ambient temperatures from -40 C to 70 C. A current project aims to extend the refrigeration power to 500 watts at 80 K. Experimental optimisation techniques have been devised for rapid development of high efficiency coolers

  10. Oxford MDM-2 magnetic spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Pringle, D.M.; Catford, W.N.; Winfield, J.S.; Lewis, D.G.; Jelley, N.A.; Allen, K.W.; Coupland, J.H.


    A new high resolution magnetic spectrometer - the Oxford MDM-2 spectrometer - has been designed, installed and tested. The layout of the magnetic elements is in the order: entrance sextupole and multipole, gradient-field dipole and exit multipole. The device has a ''normal'' focal plane, and the 1.6 m radius dipole magnet has a maximum mass-energy product of 315 MeV amu. At the maximum solid angle of 8 msr, the ratio of energies that can be accepted by the spectrometer (Esub(max)/Esub(min)) is 1.31. Precise measurements have been performed on the magnetic elements. The dipole magnet has very low hysteresis and field integral errors that amount to less than 1 part in 10/sup 4/. After some in situ modifications the field distributions of the magnets closely approximated the original design specifications. On-line tests with various ion-beams have revealed the optimum setting for each element. These are close to theoretical predictions from the program RAYTRACE, incorporating the parameterised results of the magnetic measurements. An aberration limited resolution (E/ of greater than 3000 has been observed at 8 msr solid angle.

  11. Book Review: Die Oxford Kortspelgids | Ponelis | Lexikos

    African Journals Online (AJOL)

    Book Title: Die Oxford Kortspelgids. Book Author: A.S. Coetser. 1ste uitgawe 1993, ix + 379 pp. ISBN 0-19-570802-4. Kaapstad: Oxford University Press. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL.

  12. Skyrmions and Hall viscosity


    Kim, Bom Soo


    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 physica...

  13. Quantum spin Hall phases

    International Nuclear Information System (INIS)

    Murakami, Shuichi


    We review our recent theoretical works on the quantum spin Hall effect. First we compare edge states in various 2D systems, and see whether they are robust or fragile against perturbations. Through the comparisons we see the robust nature of edge states in 2D quantum spin Hall phases. We see how it is protected by the Z 2 topological number, and reveal the nature of the Z 2 topological number by studying the phase transition between the quantum spin Hall and insulator phases. We also review our theoretical proposal of the ultrathin bismuth film as a candidate to the 2D quantum spin Hall system. (author)

  14. Leadership Styles of Oxford House Officers. (United States)

    Komer, Anne C; Jason, Leonard A; Harvey, Ronald; Olson, Brad

    Oxford House recovery homes are unusual compared to most recovery homes in that they function entirely without the use of staff; instead members are elected to officer positions. The aim of this study was to perform preliminary analysis of the types of leadership styles utilized by members of oxford house. Twentynine house residents of five Oxford Houses were asked to rate their own leadership styles using the leader behavior description questionnaire and the multifactor leader questionnaire. Results showed that participants were more likely to use person-oriented behaviors above task-oriented actions. Transformational leadership was associated with higher outcomes than Transactional leadership. Implications for future research are discussed.

  15. Facility Focus: Residence Halls. (United States)

    College Planning & Management, 2003


    Describes four examples of residence hall design, one renovation and three new residence halls, that exemplify design principles that meet student and institutional requirements. The examples are at (1) the University of Illinois at Chicago; (2) Bowdoin College; (3) Muhlenberg College; and (4) Spring Arbor University. (SLD)

  16. Healthy Dining Hall Eating (United States)

    ... Healthy Dining Hall Eating What's in this article? Good Intentions What Does Your Body Need? Choosing Carbs Choosing Veggies (and Fruit) Choosing Protein Choosing Dairy Snack Attacks Meeting Special Dietary Needs Portion Sizes Portion ...

  17. Halls Lake 1990 (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...

  18. The Oxford handbook of economic inequality

    NARCIS (Netherlands)

    Salverda, W.; Nolan, B.; Smeeding, T.M.


    The essential guide for students and researchers interested in economic inequality Contains 27 original research contributions from the top names in economic inequality. The Oxford Handbook of Economic Inequality presents a new and challenging analysis of economic inequality, focusing primarily on

  19. Oxford House Recovery Homes: Characteristics and Effectiveness (United States)

    Jason, Leonard A.; Ferrari, Joseph R.


    One of the largest examples of a community-based, mutual-help residential community for high risk substance abuse individuals is Oxford House. In the U.S., over 9,800 people live in these self-run dwellings where they obtain jobs, pay utility bills, and learn to be responsible citizens. Beginning with one single rented residence in the mid 1970s, Oxford Houses now number over 1,300. These rented homes are helping to deal with drug addiction and community re-entry by providing stable housing without any limits on length of stay, a network of job opportunities, and support for abstinence. An exploration of the research on these unique settings highlights the strengths of such a community-based approach to addressing addiction. New roles for psychologists in working with these types of support systems are identified. PMID:20577571

  20. The Manchester?Oxford Foot Questionnaire (MOXFQ)


    Morley, D.; Jenkinson, C.; Doll, H.; Lavis, G.; Sharp, R.; Cooke, P.; Dawson, J.


    OBJECTIVES: The Manchester-Oxford Foot Questionnaire (MOXFQ) is a validated 16-item, patient-reported outcome measure for evaluating outcomes of foot or ankle surgery. The original development of the instrument identified three domains. This present study examined whether the three domains could legitimately be summed to provide a single summary index score. METHODS: The MOXFQ and Short-Form (SF)-36 were administered to 671 patients before surgery of the foot or ankle. Data from the three dom...

  1. Hall effect in hopping regime

    Energy Technology Data Exchange (ETDEWEB)

    Avdonin, A., E-mail: [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)


    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.

  2. Hall Sweet Home (United States)

    Oguntoyinbo, Lekan


    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…

  3. Spin Hall noise

    NARCIS (Netherlands)

    Kamra, A.; Witek, F.P.; Meyer, S.; Huebl, H.; Geprägs, S.; Gross, R.; Bauer, G.E.W.; Goennenwein, S.T.B.


    We measure the low-frequency thermal fluctuations of pure spin current in a platinum film deposited on yttrium iron garnet via the inverse spin Hall effect (ISHE)-mediated voltage noise as a function of the angle ? between the magnetization and the transport direction. The results are consistent

  4. Anomalous Hall effect

    Czech Academy of Sciences Publication Activity Database

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


    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

  5. The Monty Hall Dilemma. (United States)

    Granberg, Donald; Brown, Thad A.


    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)

  6. Development of thermoluminescence dating techniques at Oxford

    International Nuclear Information System (INIS)

    Fleming, S.J.


    The two-decade long history of thermoluminescene as a pottery dating method is surveyed with particular reference to the various problems that have been encountered in the Oxford Laboratory's research programme. Effects, such as supralinearity and radon emanation, are explained in terms of how they are measured and how their existence influences thermoluminescence (TL) dating accuracy (currently close to plus minus 7% per analysis). Illustrations of Thermoluminescence (TL) applications include a Nok culture terracotta from Nigeria and a Cambodia bronze Buddha figure of the Khmer period, dated ising the ceramic-like casting-core retained within it. (author)

  7. Miglustat. Oxford GlycoSciences/Actelion. (United States)

    Lachmann, Robin H


    Oxford GlycoSciences and Actelion have developed and launched miglustat (OGT-918; Vevesca; Zavesca) for the treatment of type 1 Gaucher disease. Miglustat is an orally administered small-molecule glucosylceramide glucosyltransferase inhibitor licensed from Searle, and it is also in development for the treatment of other glycolipid storage disorders such as Tay-Sachs, Fabry and Niemann-Pick type C diseases. In November 2002, miglustat received EU approval for the treatment of Gaucher disease and was launched in the UK in March 2003 by Actelion. At this time, additional EU launches were expected over the next few months.

  8. Magnetometria por efeito Hall


    Fernández Pinto, Janeth


    Construímos um magnetômetro utilizando dois sensores Hall de GaAs (Toshiba- THS118) operando em um modo diferencial. Cada sensor tem um circuito préamplificador associado a ele e a diferencia de voltagem entre eles é amplificada com um ganho variável de 30 - 7000. Os sensores Hall têm dimensões típicas de 1,5 x 1,7 x 0,6 mm3 e foram montados separados um do outro de 0,71 mm, em uma configuração espacial planar. O magnetômetro foi testado usando tanto correntes dc (Idc) quant...

  9. Oxford CyberSEM: remote microscopy

    International Nuclear Information System (INIS)

    Rahman, M; Kirkland, A; Cockayne, D; Meyer, R


    The Internet has enabled researchers to communicate over vast geographical distances, sharing ideas and documents. e-Science, underpinned by Grid and Web Services, has enabled electronic communications to the next level where, in addition to document sharing, researchers can increasingly control high precision scientific instruments over the network. The Oxford CyberSEM project developed a simple Java applet via which samples placed in a JEOL 5510LV Scanning Electron Microscope (SEM) can be manipulated and examined collaboratively over the Internet. Designed with schoolchildren in mind, CyberSEM does not require any additional hardware or software other than a generic Java-enabled web browser. This paper reflects on both the technical and social challenges in designing real-time systems for controlling scientific equipments in collaborative environments. Furthermore, it proposes potential deployment beyond the classroom setting.

  10. Paired Hall states

    International Nuclear Information System (INIS)

    Greiter, M.


    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

  11. Planar Hall Effect MRAM


    Bason, Y.; Klein, L.; Yau, J. -B.; Hong, X.; Hoffman, J.; Ahn, C. H.


    We suggest a new type of magnetic random access memory (MRAM) that is based on the phenomenon of the planar Hall effect (PHE) in magnetic films, and we demonstrate this idea with manganite films. The PHE-MRAM is structurally simpler than currently developed MRAM that is based on magnetoresistance tunnel junctions (MTJ), with the tunnel junction structure being replaced by a single layer film.

  12. Spin Hall effect devices

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Tomáš; Wunderlich, Joerg; Olejník, Kamil


    Roč. 11, č. 5 (2012), s. 382-390 ISSN 1476-1122 EU Projects: European Commission(XE) 268066 - 0MSPIN; 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: 35.749, year: 2012

  13. Spin Hall effect

    Czech Academy of Sciences Publication Activity Database

    Sinova, Jairo; Valenzuela, O.V.; Wunderlich, Joerg; Back, C.H.; Jungwirth, Tomáš


    Roč. 87, č. 4 (2015), s. 1213-1259 ISSN 0034-6861 R&D Projects: GA MŠk(CZ) LM2011026; GA ČR GB14-37427G EU Projects: European Commission(XE) 268066 - 0MSPIN Institutional support: RVO:68378271 Keywords : spin Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 33.177, year: 2015


    Directory of Open Access Journals (Sweden)

    Michael Kent


    Full Text Available DESCRIPTION The Oxford Dictionary of Sports Science and Medicine provides reliable definitions of sports science and medicine terms. It provides an invaluable reference book for anyone interested in the captivating subject of sport. PURPOSE This dictionary aims to include almost every sports science, anatomy, physiology, biomechanical, injuries description, and psychological term as related to sports medicine and science and support the explanations by illustrations wherever necessary. AUDIENCE As a comprehensive dictionary of sports science and medicine, it will be of particular help to medical specialists and general practitioners, as well as students of PE, coaches, and athletes who need to understand the anatomical structures and physiological processes which affect athletic performance. Any member of public interested in health and fitness; exercise and sport or wants to understand what the obscure terms mean, like jogger's nipple, social loafing, and Zatopek phenomenon will also benefit from this book. FEATURES The Oxford Dictionary of Sports Science and Medicine features terms in A to Z fashion at all the major areas of sports science and medicine including: anatomy, physiology/exercise physiology, biomechanics, training principles and techniques, nutrition, sports psychology and sociology, sports injuries and rehabilitation. A team of prominent contributors and advisers put together this dictionary in the first edition. The third edition includes around 8000 cross-referenced terms which have been updated or added since the first edition. There are plenty of illustrations wherever appropriate to make the terms easily understandable. ASSESSMENT A must-have dictionary for all medics practising in sports and exercise medicine, as well as students of medicine, physical education, nursing and physiotherapy. Even coaches, trainers, biomechanical experts; in fact anyone who has a special interest in this area will find this dictionary useful.

  15. Quantum critical Hall exponents

    CERN Document Server

    Lütken, C A


    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...

  16. The Manchester–Oxford Foot Questionnaire (MOXFQ) (United States)

    Morley, D.; Jenkinson, C.; Doll, H.; Lavis, G.; Sharp, R.; Cooke, P.; Dawson, J.


    Objectives The Manchester–Oxford Foot Questionnaire (MOXFQ) is a validated 16-item, patient-reported outcome measure for evaluating outcomes of foot or ankle surgery. The original development of the instrument identified three domains. This present study examined whether the three domains could legitimately be summed to provide a single summary index score. Methods The MOXFQ and Short-Form (SF)-36 were administered to 671 patients before surgery of the foot or ankle. Data from the three domains of the MOXFQ (pain, walking/standing and social interaction) were subjected to higher order factor analysis. Reliability and validity of the summary index score was assessed. Results The mean age of the participants was 52.8 years (sd 15.68; 18 to 89). Higher order principle components factor analysis produced one factor, accounting for 74.7% of the variance. The newly derived single index score was found to be internally reliable (α = 0.93) and valid, achieving at least moderate correlations (r ≥ 0.5, p < 0.001) with related (pain/function) domains of the SF-36. Conclusions Analyses indicated that data from the MOXFQ can be presented in summary form. The MOXFQ summary index score (MOXFQ-Index) provides an overall indication of the outcomes of foot and ankle surgery. Furthermore, the single index reduces the number of statistical comparisons, and hence the role of chance, when exploring MOXFQ data. PMID:23673374

  17. The new Oxford dictionary of English

    CERN Document Server

    Hanks, Patrick


    This dictionary focuses on English as it is really used in the late 20th century, informed by available evidence and thinking. Its defining style makes it possible to give the most complete picture of English as it is used today, providing authoritative and comprehensive coverage of the language. Compiled after in-depth analysis of computerized databases of current English, this dictionary is the first to base its coverage on the evidence of real English. Accessibility is one of the dictionary's key aims; a rapid-reference page design separates out parts of speech, word histories, phrases, and derivatives to make information easy to find, and the most modern meaning of each word, as used by the majority of people, is placed first within each entry. Contemporary rules are given on question of usage, providing relevant advice on problems old and new. Word history notes not only explain the linguistic roots of words, but also tell the story of how a word's meaning and form have changed over time. Oxford's worldw...

  18. Quantum hall effect. A perspective

    International Nuclear Information System (INIS)

    Aoki, Hideo


    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)

  19. Magnesium Hall Thruster (United States)

    Szabo, James J.


    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.

  20. 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


    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

  1. The Oxford History of English Lexicography. Volume I: General ...

    African Journals Online (AJOL)

    A.P. Cowie (Editor). The Oxford History of English Lexicography. Volume I: General-purpose Dictionaries. Volume II: Specialized Dictionaries. 2009. Volume I: xviii + 467 pp., Volume II: xix + 551 pp. ISBN Volume I–II: 978-0-19-928562-4. Volume I: 978-0-19-928560-0. Volume II: 978-0-19-928561-7. Oxford: Oxford University ...

  2. Lymphoproliferative disorders in Oxford renal transplant recipients. (United States)

    Bates, W D; Gray, D W R; Dada, M A; Chetty, R; Gatter, K C; Davies, D R; Morris, P J


    Increased cancer incidence, particularly lymphoproliferative disease, is a complication of immunosuppression in organ transplantation. Non-Hodgkin's lymphomas (NHLs) occur frequently during the first year after transplantation, more so in North America than in Europe. This study audited and correlated the demographic, clinical, pathological, and outcome features of post-transplant lymphoproliferative disorders (PTLDs) in a large centre in Oxford, and assessed whether the time of onset fitted more with the European or North American pattern. There were 1383 renal transplants in the study period and 27 patients developed lymphoma: 26 NHLs and one Hodgkin's disease (1.95%). Four of the patients never received cyclosporin. The mean time of diagnosis after transplant was 46 months. Most tumours (21/27) presented extranodally. Management included reduction of immunosuppression, surgical excision, antiviral treatment, radiotherapy, and chemotherapy. Three patients presented in the first post-transplant year-0.34% of cyclosporin managed patients-similar to the North American incidence, although the incidence of extranodal late PTLDs was also high (mean onset, 36 months v 15 months international mean). Post-transplant lymphomas were the most common malignancy associated with death in transplant patients. PTLDs occurred in 2% of renal transplant patients, presenting both in the first year in association with cyclosporin use, as in North America, but also in subsequent years, giving an overall presentation time later than the international mean. The disease usually presented extranodally, accounting for the wide range of symptoms and signs. Despite awareness and active management, the disease contributed to death in more that 50% of patients with PTLDs.

  3. The ISOLDE hall

    CERN Multimedia

    Maximilien Brice


    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...

  4. BOOK REVIEW: The Oxford Companion to Cosmology (United States)

    Coles, Peter


    Cosmology has a special status as a science, as it strives to combine the quantitative statistical rigour of observational astronomy with a theoretical framework emerging from rather speculative ideas about fundamental physics. It also has wider repercussions too, as the quest for an understanding of the origin of the Universe sometimes strays into territory traditionally associated with religious modes of enquiry. The Oxford Companion to Cosmology aims to provide a 'comprehensive but accessible overview' of this 'enduringly popular subject' suitable for students, teachers and others with a serious interest in cosmology. It consists of an introductory overview about the big bang cosmological model, followed by an encyclopedia-like section containing over 300 entries of varying length and technical level. One of the authors (Liddle) is a theorist and the other (Loveday) an observer, so between them they have sufficient authority to cover all aspects of the vigorous interplay between these two facets of the discipline. This is not the sort of volume that can easily be read from cover to cover. The best way to test its effectiveness is to dip into it randomly. In my sampling of the entries I found most to be well-written and informative. The first entry I looked at ('correlation function') had an incorrect formula in it, but I didn't find any further significant errors, which says something about the limitations of statistical inference! The only criticisms I have are very minor. Some of the figures are so small as to be virtually invisible to an oldie like me. I also think the book would have benefitted from more references, and am not sure the web links given in their place will prove very useful as these tend to be rather ephemeral. Overall, though, I would say that the book succeeds admirably in its aims. About ten years ago, I was involved in compiling a similar volume, which ended up as The Routledge Companion to the New Cosmology. I will refrain from trying to

  5. Farm Hall: The Play (United States)

    Cassidy, David C.


    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.

  6. Hall Effect Gyrators and Circulators (United States)

    Viola, Giovanni; DiVincenzo, David P.


    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.

  7. Hall Effect Gyrators and Circulators

    Directory of Open Access Journals (Sweden)

    Giovanni Viola


    Full Text Available 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.

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

    KAUST Repository

    Ndiaye, Papa Birame


    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.

  9. City and Town Halls; townHalls13 (United States)

    University of Rhode Island Geospatial Extension Program — Locations of city and town halls in Rhode Island. Derived using information originally compiled by the State of Rhode Island (, and built upon...

  10. Anomalous Hall effect (United States)

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


    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

  11. Gauge invariance and fractional quantized Hall effect

    International Nuclear Information System (INIS)

    Tao, R.; Wu, Y.S.


    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

  12. A game generalizing Hall's theorem


    Rabern, Landon


    We characterize the initial positions from which the first player has a winning strategy in a certain two-player game. This provides a generalization of Hall's theorem. Vizing's edge coloring theorem follows from a special case.

  13. Shared Magnetics Hall Thruster Project (United States)

    National Aeronautics and Space Administration — In the proposed Phase II program, Busek Co. will demonstrate an innovative methodology for clustering Hall thrusters into a high performance, very high power...

  14. Shared Magnetics Hall Thruster Project (United States)

    National Aeronautics and Space Administration — In the proposed Phase I program, Busek Co. will demonstrate an innovative methodology for clustering Hall thrusters into a high performance, very high power...

  15. "Hall mees" Linnateatris / Triin Sinissaar

    Index Scriptorium Estoniae

    Sinissaar, Triin


    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

  16. Sheldon-Hall syndrome

    Directory of Open Access Journals (Sweden)

    Bamshad Michael J


    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.

  17. Theory of spin Hall effect


    Chudnovsky, Eugene M.


    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...

  18. Transport Signatures of the Hall Viscosity. (United States)

    Delacrétaz, Luca V; Gromov, Andrey


    Hall viscosity is a nondissipative response function describing momentum transport in two-dimensional systems with broken parity. It is quantized in the quantum Hall regime, and contains information about the topological order of the quantum Hall state. Hall viscosity can distinguish different quantum Hall states with identical Hall conductances, but different topological order. To date, an experimentally accessible signature of Hall viscosity is lacking. We exploit the fact that Hall viscosity contributes to charge transport at finite wavelengths, and can therefore be extracted from nonlocal resistance measurements in inhomogeneous charge flows. We explain how to determine the Hall viscosity from such a transport experiment. In particular, we show that the profile of the electrochemical potential close to contacts where current is injected is sensitive to the value of the Hall viscosity.

  19. Not your grandfather's concert hall (United States)

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


    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.

  20. Iodine Hall Thruster (United States)

    Szabo, James


    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).

  1. Parroquia católica en Oxford, Gran Bretaña

    Directory of Open Access Journals (Sweden)

    Ahrends, Peter


    Full Text Available This strange new building was commissioned Í0 accommodate the expanding activities of the Newman Community which acts as a religious and social center for the Catholics of the University of Oxford. The following have been constructed: a chapel, a multiple-use room, entrance hall, bar, library, meeting room, eight bedrooms, small lounges and kitchen, etc. Part of the already existing building was used for the installation of another kitchen and several bathrooms. The best possible advantage has been taken of the lot which is narrow and irregularly shaped. Construction consists basically of brick walls, with columns, reinforced concrete stairs and castings.Este curioso y nuevo edificio se ha edificado para subsanar la creciente expansión de actividades de la Comunidad Newman, que actúa como centro religioso y social para los católicos de la Universidad de Oxford. Han sido construidos: una capilla, una sala de usos múltiples, entrada, bar, biblioteca, sala de reuniones, ocho dormitorios, pequeñas salitas y cocina, etc., aprovechando parte del edificio existente para ubicar otra cocina y varios cuartos de baño. El solar, que era estrecho y de forma irregular, se ha aprovechado al máximo. La construcción se ha llevado a cabo, fundamentalmente, a base de muros de fábrica de ladrillo, con pilares, forjados y escaleras de hormigón armado.

  2. A Site-Specific Index Based on Weathering Forms Visible in Central Oxford, UK

    Directory of Open Access Journals (Sweden)

    Mary J. Thornbush


    Full Text Available The authenticity of much of the stone-work along Queen’s Lane in central Oxford, UK presented an opportunity to produce a photographic survey from which a weathering index could be established. This represents a site-specific approach to devising a weathering form. Because it is photo-based, weathering forms are visible for comparison and classification purposes across disciplines. Limestone pertaining to building ashlar and plinths along this roadway, which mainly belong to Queen’s College, St Edmund Hall, New College, and Hertford College, was classified according to this newly introduced weathering index, the size-extent (S-E index, through consideration of type, size, extent, impact, and trigger. This size- (range and extent-based classification system enables for the assessment of weathering forms of various types, including soiling and decay features as well as those potentially expected in the presence of vegetation and animals. Weathering forms of a range of sizes were present, with a slightly greater abundance of small types (mm-cm in the micro- to mesoscale and more discrete types with a low extent. For this location in central Oxford, chemical weathering was found to be the predominant type of soiling and decay.

  3. News from the Library: You need never be lost for words again - Oxford Reference Online and Oxford Dictionaries Pro

    CERN Document Server

    CERN Library


    Whether you are looking for an English word definition or want to check the correct usage of a word, we can offer you a solution: Oxford Reference Online.   It includes a wide range of monolingual and bilingual dictionaries, but also subject-specific reference books on physics, astronomy or mathematics. All these works are fully indexed and cross-searchable. Two highlights from this vast collection of reference works are the Concise Oxford English Dictionary and the Oxford Dictionary of English, which is the online counterpart of the compact, single-volume dictionary of current English language. As the name says, Oxford Dictionaries Pro focuses on language dictionaries. Particularly noteworthy are the dictionaries for writers and editors. On a dedicated web page you will find access to: - The "New Hart's Rules", providing information on all aspects of writing and preparing copy for publication, whether in print or electronically - The New Oxford Dictionary for Wri...

  4. Women leadership in Oxford House: examining their strengths and challenges. (United States)

    Davis, Margaret I; Dziekan, Marta M; Horin, Elizabeth V; Jason, Leonard A; Ferrari, Joseph R; Olson, Bradley D


    This study examined the perspectives and definition of leadership by women and mothers with children (n = 40) affiliated with Oxford Houses, a communal mutual-help recovery setting. Participants were asked questions relating to their experiences living in an Oxford House including the strengths and challenges encountered and how leadership impacted the stability in their house. Results illustrated the value of female leadership and highlighted the characteristics deemed important for women leaders in Oxford House, as well as some differences between these women's perception of leadership and the standard definition of leadership. The implications of the findings and how they may be useful to women's and mothers' with children houses are discussed.

  5. Oxford engineering students to study new solutions for vacuum chambers

    CERN Multimedia

    Department of Engineering Science - University of Oxford


    In April, eleven engineering science students in their third year at Oxford University were invited here to present their design ideas for new vacuum chamber materials to be used in accelerators. We publish below an abstract of the article that the University of Oxford featured on its website.   The 11 Oxford students who worked at CERN on alternatives to beryllium in vacuum chambers. (Photo courtesy of the Department of Engineering Science, University of Oxford.) Engineering Science students invited to design for CERN’s Large Hadron Collider In April, eleven Engineering Science students in their third year were invited to the CERN laboratory in Geneva to present their ideas for new vacuum chamber designs for the experiments of the Large Hadron Collider (LHC). Their design objectives were to propose alternatives to beryllium – the material used for some of the existing experimental vacuum chambers. Beryllium (chemical element with the symbol Be and atomic number 4) is to...

  6. Early recovery after fast-track Oxford unicompartmental knee arthroplasty

    DEFF Research Database (Denmark)

    Munk, Stig; Dalsgaard, Jesper; Bjerggaard, Karin


    trauma. We investigated changes in leg-extension power (LEP) in the first month after MIS Oxford UKA and its relation to pain, knee motion, functional performance, and knee function. Patients and methods In 35 consecutive Oxford UKA patients, LEP was measured 1 week before and 1 month after surgery...... together with knee motion, knee swelling, the 30-second chair-stand test, and Oxford knee score. Assessment of knee pain at rest and walking was done using a visual analog scale. Results 30 patients were discharged on the day after surgery, and 5 on the second day after surgery. LEP and functional...... supervision in the first month after discharge. Interpretation Fast-track MIS Oxford UKA with discharge on the day after surgery is safe and leads to early recovery of knee motion and strength even when no physiotherapy is used....

  7. ac spin-Hall effect

    International Nuclear Information System (INIS)

    Entin-Wohlman, O.


    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

  8. Novel concepts in Hall sensors (United States)

    Mani, R. G.


    Hall effect devices are widely used as position sensors and contactless switches in applications ranging from electric motors to soft drink machines and automobiles. Such devices typically operate in an adverse environment where offset voltages originating from various physical effects limit the effective sensitivity of the sensor to the weak magnetic field (B device that automatically reduces such spurious offsets is desirable because improved 'signal to offset' would relax manufacturing tolerances and other constraints within the sensor system. Here, we examine some techniques and sensor configurations (R. G. Mani, K. von Klitzing, F. Jost, K. Marx, S. Lindenkreuz, and H. P. Trah, Appl. Phys. Lett. 67, 2223, 1995.) based on the so called 'anti Hall bar' geometry that promise the possibility of a Silicon based Hall sensor with a field equivalent offset well below 1 mT.

  9. Computational Modeling of Hall Thruster Erosion (United States)

    National Aeronautics and Space Administration — Hall thrusters are being developed by NASA, DOD, and industry to meet a variety of on-board space propulsion needs. Hall thrusters have been operated successfully...

  10. ATLAS Assembly Hall Open Day

    CERN Multimedia

    Patrice Loiez


    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.

  11. The Other Hall Effect: College Board Physics (United States)

    Sheppard, Keith; Gunning, Amanda M.


    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…

  12. The Relationship Between Neighborhood Criminal Behavior and Oxford Houses. (United States)

    Deaner, Jeffrey; Jason, Leonard A; Aase, Darrin M; Mueller, David G


    The present study investigated crime rates in areas surrounding 42 Oxford Houses and 42 control houses in a large city in the Northwestern United States. A city-run Global Information Systems' (GIS) website was used to gather crime data including assault, arson, burglary, larceny, robbery, sexual assault, homicide, and vehicle theft over a calendar year. Findings indicated that there were no significant differences between the crime rates around Oxford Houses and the control houses. These results suggest that well-managed and governed recovery homes pose minimal risks to neighbors in terms of criminal behavior.

  13. Oxford phase III meniscal bearing fracture: case report. (United States)

    Lim, Hong-Chul; Shon, Won-Yong; Kim, Seung-Ju; Bae, Ji-Hoon


    Meniscal bearing fracture is a rare complication of phase III Oxford unicompartmental knee replacement (UKR). We report a case of a meniscal bearing fracture that occurred 7 years after phase III Oxford medial UKR. The meniscal bearing showed uneven delamination of the polyethylene in the thinnest articular surface and an impingement lesion. This lesion initiated a fatigue crack that propagated to cause failure of the meniscal bearing. This is the first report of a meniscal bearing fracture without a posterior marker wire. © 2013.

  14. Validation of the Danish version of Oxford Shoulder Score

    DEFF Research Database (Denmark)

    Frich, Lars Henrik; Noergaard, Peter Moensted; Brorson, Stig


    The Oxford Shoulder Score (OSS) is a patient-administered condition-specific questionnaire for patients with degenerative or inflammatory shoulder disease. The purpose of this study was to validate a Danish translation of the OSS and to compare it with the Constant Score (CS).......The Oxford Shoulder Score (OSS) is a patient-administered condition-specific questionnaire for patients with degenerative or inflammatory shoulder disease. The purpose of this study was to validate a Danish translation of the OSS and to compare it with the Constant Score (CS)....

  15. Performance of the Oxford miniature Stirling cycle refrigerator

    International Nuclear Information System (INIS)

    Bradshaw, T.W.; Davey, G.; Delderfield, J.; Werrett, S.T.


    The performance of the Oxford Cryocooler is summarized. This cooler has been developed for space use by the Rutherford Appleton Laboratory and the Departments of Atmospheric Physics and Engineering Science at Oxford University. The design goal of 1/2 watt of cooling power at 80 K for 30 W electrical input power has been exceeded by a substantial amount. The power budget for the compressor and the losses in the displacer are discussed. Graphs of the cold end temperature vs. compressor input power and cooling power are presented

  16. Joyce M. Hawkins (Compiler). The South African Oxford School Diction

    African Journals Online (AJOL)

    tant dictionary may appear out of touch and out of date. The South African Oxford School Dictionary has a sense of out-datedness about it. While it would be absurd to demand that a dictionary for schools should be up to date when new words are pouring into English all the time, one would hope that the world of the nineties ...

  17. Validation of the Danish version of the Oxford Elbow Score

    DEFF Research Database (Denmark)

    Plaschke, Hans Christian; Jørgensen, Andreas Møller; Thillemann, Theis Muncholm


    The Oxford Elbow Score (OES) is a patient-related outcome measure quantifying quality of life in relation to elbow disorders. This 12-item patient-administered English questionnaire comprises three domains: function, social-psychological status and pain. The purpose of this study was to examine...

  18. An Analysis of the Oxford Bilingual School Dictionary: Northern ...

    African Journals Online (AJOL)

    The Oxford Bilingual School Dictionary: Northern Sotho and English (De Schryver 2007) is a welcome addition to dictionaries that have been compiled for school use in particular. Its novelty and appeal lie in the fact that the lemmas and Northern Sotho mini-grammar are based on a corpus of general language usage and ...

  19. PEOPLE IN PHYSICS: Interview with Scott Durow, Software Engineer, Oxford (United States)

    Burton, Conducted by Paul


    Scott Durow was educated at Bootham School, York. He studied Physics, Mathematics and Chemistry to A-level and went on to Nottingham University to read Medical Physics. After graduating from Nottingham he embarked on his present career as a Software Engineer based in Oxford. He is a musician in his spare time, as a member of a band and playing the French horn.

  20. Changing Traditions: Automation and the Oxford College Libraries. (United States)

    Bell, Suzanne


    Discussion of automation in the Oxford College Libraries (England) begins with background on the university library system, which consists of numerous independent libraries. Centralized and decentralized automation activities are described, and hardware and software for the microcomputer-based system at the University College Library are…

  1. Scanning vector Hall probe microscope

    Czech Academy of Sciences Publication Activity Database

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


    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

  2. Tunneling Anomalous and Spin Hall Effects. (United States)

    Matos-Abiague, A; Fabian, J


    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.

  3. Spin Hall effect by surface roughness

    KAUST Repository

    Zhou, Lingjun


    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.

  4. Pulsed and high temperature superconducting magnet technology in Oxford (United States)

    Jones, H.; Jenkins, R. G.; Van Cleemput, M.; Nicholas, R. J.; Siertsema, W. J.; van der Burgt, M.


    We present a brief account of the Oxford pulsed field facility. Multisection coils for fields of 50 T in 20 mm bores are described and a specific example is discussed. Two design studies for mixing stationary or quasi-stationary platform field magnets with pulsed coils for fields of 75 T and higher are outlined. Work on the application of high temperature superconductors to magnet technology is also reported.

  5. Nanocall: an open source basecaller for Oxford Nanopore sequencing data. (United States)

    David, Matei; Dursi, L J; Yao, Delia; Boutros, Paul C; Simpson, Jared T


    The highly portable Oxford Nanopore MinION sequencer has enabled new applications of genome sequencing directly in the field. However, the MinION currently relies on a cloud computing platform, Metrichor (, for translating locally generated sequencing data into basecalls. To allow offline and private analysis of MinION data, we created Nanocall. Nanocall is the first freely available, open-source basecaller for Oxford Nanopore sequencing data and does not require an internet connection. Using R7.3 chemistry, on two E.coli and two human samples, with natural as well as PCR-amplified DNA, Nanocall reads have ∼68% identity, directly comparable to Metrichor '1D' data. Further, Nanocall is efficient, processing ∼2500 Kbp of sequence per core hour using the fastest settings, and fully parallelized. Using a 4 core desktop computer, Nanocall could basecall a MinION sequencing run in real time. Metrichor provides the ability to integrate the '1D' sequencing of template and complement strands of a single DNA molecule, and create a '2D' read. Nanocall does not currently integrate this technology, and addition of this capability will be an important future development. In summary, Nanocall is the first open-source, freely available, off-line basecaller for Oxford Nanopore sequencing data. Nanocall is available at, released under the MIT license. matei.david@oicr.on.caSupplementary information: Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press.

  6. Short Pulses THz FEL for the Oxford Accelerator Science Laboratory


    Chanwattana, Thakonwat; Bartolini, Riccardo; Seryi, Andrei; Bartolini, Riccardo; Tsesmelis, Emmanuel


    The Accelerator Science Laboratory (ASL) is under development at the John Adams Institute in Oxford with the aim of fostering advanced accelerator concepts and applications. The option to install a short pulse THz FEL based on a conventional RF accelerator driven by a RF photocathode gun is being investigated. This report presents the concept of the facility, the accelerator physics and FEL studies and engineering integration in the University physics department.

  7. Dobson total ozone series of Oxford: Reevaluation and applications (United States)

    Vogler, C.; BröNnimann, S.; Staehelin, J.; Griffin, R. E. M.


    We have reevaluated the original total ozone measurements made in Oxford between 1924 and 1957, with a view to extending backward in time the existing total ozone series from 1957 to 1975. The Oxford measurements are the oldest Dobson observations in the world. Their prime importance, when coupled with the series from Arosa (since 1926) and Tromsø (since 1935), is for increasing basic understanding of stratospheric ozone and dynamics, while in relation to studies of the recent ozone depletion they constitute a baseline of considerable (and unique) significance and value. However, the reevaluation was made difficult on account of changes to the instruments and wavelengths as the early data collection methods evolved, while unknowns due to the influence of aerosols and the possible presence of dioxides of sulphur and nitrogen created additional problems. Our reevaluation was based on statistical procedures (comparisons with meteorological upper air data and ozone series from Arosa) and also on corrections suggested by Dobson himself. The comparisons demonstrate that the data are internally consistent and of good quality. Nevertheless, as post-1957 data were not assessed in this study, the series cannot be recommended at present for trend analysis, though the series can be used for climatological studies. By supplementing the Oxford data with other existing series, we present a European total ozone climatology for 1924-1939, 1950-1965, and 1988-2000 and analyze the data with respect to variables measuring the strength and the temperature of the polar vortex.

  8. 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


    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.

  9. Planar Hall effect bridge magnetic field sensors

    DEFF Research Database (Denmark)

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


    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...... be significantly enhanced by a geometric factor. For the samples in the present study, we demonstrate an enhancement of the sensor output by a factor of about 100 compared to cross-shaped sensors. The presented construction opens a new design and application area of the planar Hall effect, which we term planar...

  10. Listening to the acoustics in concert halls (United States)

    Beranek, Leo L.; Griesinger, David


    How does acoustics affect the symphonic music performed in a concert hall? The lecture begins with an illustrated discussion of the architectural features that influence the acoustics. Boston Symphony Hall, which was built in 1900 when only one facet of architectural design was known, now rates as one of the world's great halls. How this occurred will be presented. Music is composed with some acoustical environment in mind and this varies with time from the Baroque to the Romantic to the Modern musical period. Conductors vary their interpretation according to the hall they are in. Well-traveled listeners and music critics have favorite halls. The lecture then presents a list of 58 halls rank ordered according to their acoustical quality based on interviews of music critics and conductors. Modern acoustical measurements made in these halls are compared with their rankings. Music recordings will be presented that demonstrate how halls sound that have different measured acoustical parameters. Photographs of a number of recently built halls are shown as examples of how these known acoustical factors have been incorporated into architectural design.

  11. Anomalous Hall effect in polycrystalline Ni films

    KAUST Repository

    Guo, Zaibing


    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.

  12. Hall-effect arc protector (United States)

    Rankin, R.A.; Kotter, D.K.


    The Hall-Effect Arc Protector is used to protect sensitive electronics from high energy arcs. The apparatus detects arcs by monitoring an electrical conductor, of the instrument, for changes in the electromagnetic field surrounding the conductor which would be indicative of a possible arcing condition. When the magnitude of the monitored electromagnetic field exceeds a predetermined threshold, the potential for an instrument damaging are exists and the control system logic activates a high speed circuit breaker. The activation of the breaker shunts the energy imparted to the input signal through a dummy load to the ground. After the arc condition is terminated, the normal signal path is restored. 2 figs.

  13. Temperature Gradient in Hall Thrusters

    International Nuclear Information System (INIS)

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


    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

  14. Library rooms or Library halls

    Directory of Open Access Journals (Sweden)

    Alfredo Serrai


    Full Text Available Library Halls, understood as Renaissance and Baroque architectural creations, along with the furnishings and decorations, accomplish a cognitive task and serve to transmit knowledge. The design of these spaces based on the idea that they should reflect the merits and content of the collections housed within them, in order to prepare the mind of the reader to respect and admire the volumes. In accordance with this principle, in the fifteenth century library rooms had a basilican shape, with two or three naves, like churches, reflecting thus the spiritual value of the books contained there. Next to that inspiring function, library rooms had also the task of representing the entire logical and conceptual universe of human knowledge in a figurative way, including for this purpose also the and Kunst- und Wunderkammern, namely the collections of natural, artficial objects, and works of art. The importance of library rooms and their function was understood already in the early decades of the seventeenth century, as underlined in the treatise, Musei sive Bibliothecae tam privatae quam publicae Extructio, Instructio, Cura, Usus, written by the Jesuit Claude Clément and published in 1635. Almost the entire volume is dedicated to the decoration and ornamentation of the Saloni, and the function of the library is identified exclusively with the preservation and decoration of the collection, neglecting more specifically bibliographic aspects or those connected to library science. The architectural structure of the Saloni was destined to change in relation to two factors, namely the form of books, and the sources of light. As a consequence, from the end of the sixteenth century – or perhaps even before if one considers the fragments of the Library of Urbino belonging to Federico da Montefeltro – shelves and cabinets have been placed no longer in the center of the room, but were set against the walls. This new disposition of the furniture, surmounted by

  15. An Interview with Professor Paddy Scannell, Oxford, July 2006


    Sabry, Tarik


    Paddy Scannell: I had done a degree in English literature at Oxford for three years and after that, because I hadn’t a clue what I wanted to do next, I thought I might as well stay on a bit longer. So I applied to do postgraduate research in English literature. That turned out to be total waste of time and I packed it up at the end of the first year. I moved on to a postgraduate certificate in education at the University of Hull - the only place I could get into just before the start of the a...

  16. Invitational Engineering in the Residence Halls. (United States)

    Murphy, Jack; Purkey, William


    Presents various ways in which a residence hall environment may be specifically engineered to encourage individual participation in the process of education. Invitational engineering is defined as one way to transpose psychological principles to residence halls so they contribute to the developmental life of students. (RC)

  17. Quantum Hall effect in quantum electrodynamics

    International Nuclear Information System (INIS)

    Penin, Alexander A.


    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

  18. Reversal of the Hall field in indium

    International Nuclear Information System (INIS)

    Ozimek, E.J.; Leisure, R.G.; Hsu, D.K.


    The Hall effect in single crystal has been investigated at 63 kOe over the 6-280 K temperature range. The Hall coefficient reverses sign as a function of temperature. The high temperature value is less negative than theoretical predictions. (Auth.)

  19. Integral and fractional quantum Hall Ising ferromagnets

    Czech Academy of Sciences Publication Activity Database

    Výborný, Karel; Čertík, Ondřej; Pfannkuche, D.; Wodzinski, D.; Wójs, A.; Quinn, J.J.


    Roč. 75, č. 4 (2007), 045434/1-045434/10 ISSN 1098-0121 R&D Projects: GA MŠk LC510 Institutional research plan: CEZ:AV0Z10100521 Keywords : quantum Hall ferromagnet * fractional quantum Hall effect ( FQHE) * Ising ferromagnet * exact diagonalization Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.172, year: 2007

  20. 20th Annual Residence Hall Construction Report (United States)

    Agron, Joe


    Even in difficult economic times, colleges and universities continue to invest in residence hall construction projects as a way to attract new students and keep existing ones on campus. According to data from "American School & University"'s 20th annual Residence Hall Construction Report, the median new project completed in 2008 was…

  1. Mesoscopic effects in the quantum Hall regime

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 58; Issue 2 ... Mesoscopic effects; quantum Hall transitions; finite-size scaling. ... 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 ...

  2. The Scientific Humanism of G. Stanley Hall (United States)

    Meyer, Donald H.


    This paper presents the humanistic psychology of the pioneer American psychologist Granville Stanley Hall (1844-1924), examining Hall's effort to develop a system of psychology that is at once rigorously scientific and, simultaneously, capable of verifying essential human values. (Author)

  3. Novel optical probe for quantum Hall system

    Indian Academy of Sciences (India)

    to 8 T using SPV spectroscopy. Keywords. Surface photovoltage spectroscopy; quantum Hall effect; Landau levels; edge states. PACS Nos 73.43.-f; 07.60.-j; 73.43.Fj. 1. Introduction. Integer quantum Hall effect (QHE) arises from quantization of energy of two- dimensional electron gas (2DEG) under perpendicular magnetic ...

  4. Recent findings of the Oxford survey of childhood cancers

    International Nuclear Information System (INIS)

    Chiacchierini, R.P.; Stewart, A.M.; Kneale, G.W.


    The Oxford Survey of Childhood Cancers has provided valuable data and analyses concerning the effects of x-irradiation exposure of the fetus. Some important milestones in the long history of this study, two current findings, and areas where future research is being planned are discussed. An initial report by Stewart et al. indicated an association between prenatal irradiation and childhood cancer under the age of 10. These results were strengthened in a second paper in which a twofold increase in cancer risk was reported for children irradiated in utero. These findings were controversial and were not widely accepted until confirmed in another case-control study of Graham et al. a prospective study by Mac Mahon, and an historical prospective study by Diamond et al. Even today, however, there are some who point to the inconsistency between this work and the negative findings among Japanese atomic-bomb survivors as indicating a spurious relationship between in utero irradiation and childhood cancer. The history of this controversy can be traced in the literature. Since the early results were promising, the Oxford Survey has been expanded. The age limitation has been raised from age 10 to age 15 and the geographic coverage was extended to include Scotland along with England and Wales

  5. The Oxford Guide to the History of Physics and Astronomy (United States)

    Heilbron, John L.


    With over 150 alphabetically arranged entries about key scientists, concepts, discoveries, technological innovations, and learned institutions, the Oxford Guide to Physics and Astronomy traces the history of physics and astronomy from the Renaissance to the present. For students, teachers, historians, scientists, and readers of popular science books such as Galileo's Daughter , this guide deciphers the methods and philosophies of physics and astronomy as well as the historical periods from which they emerged. Meant to serve the lay reader and the professional alike, this book can be turned to for the answer to how scientists learned to measure the speed of light, or consulted for neat, careful summaries of topics as complicated as quantum field theory and as vast as the universe. The entries, each written by a noted scholar and edited by J. L. Heilbron, Professor of History and Vice Chancellor, Emeritus, University of California, Berkeley, reflect the most up-to-date research and discuss the applications of the scientific disciplines to the wider world of religion, law, war, art and literature. No other source on these two branches of science is as informative or as inviting. Thoroughly cross-referenced and accented by dozens of black and white illustrations, the Oxford Guide to Physics and Astronomy is the source to turn to for anyone looking for a quick explanation of alchemy, x-rays and any type of matter or energy in between.

  6. Monitoring of Hall's Harbor wharf (United States)

    Newhook, John P.; Bakht, Baidar; Mufti, Aftab A.; Tadros, Gamil


    The Hall's Harbour wharf in Nova Scotia is the first Canadian project to demonstrate the application of fibre reinforced polymer reinforcement, the steel-free concrete deck slab concept and fibre optic monitoring systems to structures in the marine environment. The extreme environmental exposure conditions make the site an excellent location for testing both material performance and sensing system durability. The early results of the monitoring program indicate that the innovative structure is meeting service level performance requirements. Long-term durability assessment is continuing and being complemented by controlled field and laboratory testing programs. Continuous remote monitoring of the fibre optic sensors is producing valuable reinforcement strain information for tracking structural response to ambient conditions. The fibre optic sensors themselves were found to be rugged enough to withstand the construction process and exposure environment; however, further work is required to achieve feasible field units for some types of fibre optic sensing instruments and associated equipment.

  7. Validation of the Oxford Participation and Activities Questionnaire

    Directory of Open Access Journals (Sweden)

    Morley D


    Full Text Available David Morley, Sarah Dummett, Laura Kelly, Jill Dawson, Ray Fitzpatrick, Crispin Jenkinson Health Services Research Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK Purpose: There is growing interest in the management of long-term conditions and in keeping people active and participating in the community. Testing the effectiveness of interventions that aim to affect activities and participation can be challenging without a well-developed, valid, and reliable instrument. This study therefore aims to develop a patient-reported outcome measure, the Oxford Participation and Activities Questionnaire (Ox-PAQ, which is theoretically grounded in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF and fully compliant with current best practice guidelines. Methods: Questionnaire items generated from patient interviews and based on the nine chapters of the ICF were administered by postal survey to 386 people with three neurological conditions: motor neuron disease, multiple sclerosis, and Parkinson's disease. Participants also completed the Medical Outcomes Study (MOS 36-Item Short Form Health Survey (SF-36 and EQ-5D-5L. Results: Thus, 334 participants completed the survey, a response rate of 86.5%. Factor analysis techniques identified three Ox-PAQ domains, consisting of 23 items, accounting for 72.8% of variance. Internal reliability for the three domains was high (Cronbach's α: 0.81–0.96, as was test–retest reliability (intraclass correlation: 0.83–0.92. Concurrent validity was demonstrated through highly significant relationships with relevant domains of the MOS SF-36 and the EQ-5D-5L. Assessment of known-groups validity identified significant differences in Ox-PAQ scores among the three conditions included in the survey. Conclusion: Results suggest that the Ox-PAQ is a valid and reliable measure of participation and activity. The measure will now be validated in

  8. The Oxford Participation and Activities Questionnaire: study protocol

    Directory of Open Access Journals (Sweden)

    Morley D


    Full Text Available David Morley, Sarah Dummett, Laura Kelly, Jill Dawson, Ray Fitzpatrick, Crispin JenkinsonNuffield Department of Population Health, University of Oxford, Oxford, UKBackground: With an ageing population and increasing demands on health and social care services, there is growing importance attached to the management of long-term conditions, including maximizing the cost-effectiveness of treatments. In line with this, there is increasing emphasis on the need to keep people both active and participating in daily life. Consequently, it is essential that well developed and validated instruments that can meaningfully assess levels of participation and activity are widely available. Current measures, however, are largely focused on disability and rehabilitation, and there is no measure of activity or participation for generic use that fully meets the standards set by regulatory bodies such as the US Food and Drug Administration. Here we detail a protocol for the development and validation of a new patient-reported outcome measure (PROM for assessment of participation and activity in people experiencing a variety of health conditions, ie, the Oxford Participation and Activities Questionnaire (Ox-PAQ. The stages incorporated in its development are entirely in line with current regulations and represent best practice in the development of PROMs.Methods: Development of the Ox-PAQ is theoretically grounded in the World Health Organization International Classification of Functioning, Disability, and Health. The project incorporates a new strategy of engaging with stakeholders from the outset in an attempt to identify those characteristics of PROMs considered most important to a range of potential users. Items will be generated through interviews with patients from a range of conditions. Pretesting of the instrument will be via cognitive interviews and focus groups. A postal survey will be conducted, with data subject to factor and Rasch analysis in order to

  9. Transport measurements and simulations of GaAs/AlGaAs ``anti-Hall-bar within a Hall bar'' devices (United States)

    Kriisa, Annika; Mani, Ramesh G.


    Hall effect measurements are often carried out in the Hall geometry, which is a thin rectangular plate with current and Hall voltage contacts at the external boundary. The motivation of this study is to further understand the impact on Hall effect when a hole is inserted inside Hall geometry. One way on conducting this investigation is to superimpose an ``anti-Hall bar'' inside the standard Hall bar, where the anti Hall bar is actually the hole inside the Hall device with contacts on the inside boundary of this hole. This configuration is thought to generate an ordinary Hall effect within the interior boundary such that the interior Hall voltage divided by the interior injected current equals the Hall resistance. One believes that it might also be possible to simultaneously realize multiple independent Hall effects by injecting multiple currents into the multiply connected device [1]. We have studied Hall effect in the doubly connected ``anti-Hall bar within a Hall bar'' geometry fabricated out of the GaAs/AlGaAs semiconductor system. Also the simulations of the distribution of the Hall current and potential profile within the specimen are conducted. To attain understanding of how the Hall effect arises in this geometry, the simulation plots are compared to the experimental results. [1] R. G. Mani and K. von Klitzing, App. Phys. Lett. 1993, 64, 1262-1264.

  10. The Oxford Handbook of Popular Music in the Nordic Countries

    DEFF Research Database (Denmark)

    Popular music has come to play a significant role in the political and cultural history of the Nordic countries. Research on the region's culture has largely followed national narratives created by political and economic institutions, even as cultural life in the region—which spans a large area...... of northern Europe and the North Atlantic—displays more complex geographies and evolving global dynamics. As the first of its kind, The Oxford Handbook of Popular Music in the Nordic Countries offers a series of exemplary studies of music in these transnational dynamics in the specific context of the region......'s cultures and natural environments, written by the foremost experts in the field. Chapters highlight and challenge music's place in exotic images of the North and in transnational environmentalism, tourism, racism, and media industries. The Handbook illustrates how transnational dynamics evolve and shape...

  11. The Oxford handbook of the history of physics

    CERN Document Server

    Fox, Robert


    The Oxford Handbook of the History of Physics brings together cutting-edge writing by more than twenty leading authorities on the history of physics from the seventeenth century to the present day. By presenting a wide diversity of studies in a single volume, it provides authoritative introductions to scholarly contributions that have tended to be dispersed in journals and books not easily accessible to the general reader. While the core thread remains the theories and experimental practices of physics, the Handbook contains chapters on other dimensions that have their place in any rounded history. These include the role of lecturing and textbooks in the communication of knowledge, the contribution of instrument-makers and instrument-making companies in providing for the needs of both research and lecture demonstrations, and the growing importance of the many interfaces between academic physics, industry, and the military.

  12. The quantum Hall effects: Philosophical approach (United States)

    Lederer, P.


    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.

  13. Quantized Hall conductance as a topological invariant

    International Nuclear Information System (INIS)

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


    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

  14. Spin Hall effect, Hall effect and spin precession in diffusive normal metals


    Shchelushkin, R. V.; Brataas, Arne


    We study transport in normal metals in an external magnetic field. This system exhibits an interplay between a transverse spin imbalance (spin Hall effect) caused by the spin-orbit interaction, a Hall effect via the Lorentz force, and spin precession due to the Zeeman effect. Diffusion equations for spin and charge flow are derived. The spin and charge accumulations are computed numerically in experimentally relevant thin film geometries. The out-of-plane spin Hall potential is suppressed whe...

  15. Topologically induced fractional Hall steps in the integer quantum Hall regime of MoS 2 (United States)

    Firoz Islam, SK; Benjamin, Colin


    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.

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

    Indian Academy of Sciences (India)

    Bound values for Hall conductivity under quantum Hall effect (QHE) conditions 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 conditions.

  17. Athletics hall, Odenwald school, Heppenheim, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Schuler, M. [Trans Solar GmbH, Stuttgart (Germany)


    This building, completed in 1995, is a good example of how to use a glazed foyer, not only as a climatic buffer zone, but also for preheating the inlet air by solar gains. The completely glazed west-oriented foyer is used as a huge air collector to preheat ventilation air during the heating period. The glass superstructure across the hall stores a movable curtain, serves as a skylight and enhances the natural ventilation of the hall due to the chimney effect. The stiffening ribs of the floor are also used as an air duct to the hall and as an installation duct. Photovoltaic-powered fans are used to move solar preheated air into the hall. (author)

  18. AA under construction in its hall

    CERN Multimedia

    CERN PhotoLab


    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 !

  19. Multiscale Modeling of Hall Thrusters Project (United States)

    National Aeronautics and Space Administration — New multiscale modeling capability for analyzing advanced Hall thrusters is proposed. This technology offers NASA the ability to reduce development effort of new...

  20. Light Metal Propellant Hall Thruster, Phase I (United States)

    National Aeronautics and Space Administration — Busek proposes to develop light metal Hall Effect thrusters that will help reduce the travel time, mass, and cost of SMD spacecraft. Busek has identified three...

  1. Mesoscopic effects in the quantum Hall regime

    Indian Academy of Sciences (India)

    The seven magnetic sub-bands are well separated by energy gaps at disorder strengthW =0.5. The Hall conductance of each of the q magnetic sub-bands, when they are separated by energy gaps, have been shown to be quantized [13]. The Hall conductance σ r (in units of e2/h), when the lowest r sub-bands are occupied, ...

  2. Hall effect in organic layered conductors

    Directory of Open Access Journals (Sweden)



    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.

  3. Oxford Nanopore MinION Sequencing and Genome Assembly

    Directory of Open Access Journals (Sweden)

    Hengyun Lu


    Full Text Available The revolution of genome sequencing is continuing after the successful second-generation sequencing (SGS technology. The third-generation sequencing (TGS technology, led by Pacific Biosciences (PacBio, is progressing rapidly, moving from a technology once only capable of providing data for small genome analysis, or for performing targeted screening, to one that promises high quality de novo assembly and structural variation detection for human-sized genomes. In 2014, the MinION, the first commercial sequencer using nanopore technology, was released by Oxford Nanopore Technologies (ONT. MinION identifies DNA bases by measuring the changes in electrical conductivity generated as DNA strands pass through a biological pore. Its portability, affordability, and speed in data production makes it suitable for real-time applications, the release of the long read sequencer MinION has thus generated much excitement and interest in the genomics community. While de novo genome assemblies can be cheaply produced from SGS data, assembly continuity is often relatively poor, due to the limited ability of short reads to handle long repeats. Assembly quality can be greatly improved by using TGS long reads, since repetitive regions can be easily expanded into using longer sequencing lengths, despite having higher error rates at the base level. The potential of nanopore sequencing has been demonstrated by various studies in genome surveillance at locations where rapid and reliable sequencing is needed, but where resources are limited.

  4. Review: G.-M. de Schryver et al. (Eds.). Oxford Bilingual School ...

    African Journals Online (AJOL)

    Abstract. G.-M. de Schryver et al. (Eds.). Oxford Bilingual School Dictionary: IsiXhosa and English. 2014, 562 pp. ISBN 978-0-19-576682-0. Cape Town: Oxford University Press Southern Africa. Price R129.95.

  5. Book review: Dexter Hoyos, Mastering the West. Rome and Carthage at War, Oxford-New York, Oxford University Press, 2015, pp. XXI, 337; ISBN 9780199860104

    Directory of Open Access Journals (Sweden)

    Gabriele Demurtas


    Full Text Available This essay offers a critical review of the volume by Dexter Hoyos «Mastering the West. Rome and Carthage at War», published in 2015 in Oxford-New York by the Oxford University Press, focused on the conflicts that involved Rome and Carthage between 264 and 146 BC for the supremacy in the western Mediterranean.

  6. Validation of the Oxford Participation and Activities Questionnaire. (United States)

    Morley, David; Dummett, Sarah; Kelly, Laura; Dawson, Jill; Fitzpatrick, Ray; Jenkinson, Crispin


    There is growing interest in the management of long-term conditions and in keeping people active and participating in the community. Testing the effectiveness of interventions that aim to affect activities and participation can be challenging without a well-developed, valid, and reliable instrument. This study therefore aims to develop a patient-reported outcome measure, the Oxford Participation and Activities Questionnaire (Ox-PAQ), which is theoretically grounded in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF) and fully compliant with current best practice guidelines. Questionnaire items generated from patient interviews and based on the nine chapters of the ICF were administered by postal survey to 386 people with three neurological conditions: motor neuron disease, multiple sclerosis, and Parkinson's disease. Participants also completed the Medical Outcomes Study (MOS) 36-Item Short Form Health Survey (SF-36) and EQ-5D-5L. Thus, 334 participants completed the survey, a response rate of 86.5%. Factor analysis techniques identified three Ox-PAQ domains, consisting of 23 items, accounting for 72.8% of variance. Internal reliability for the three domains was high (Cronbach's α: 0.81-0.96), as was test-retest reliability (intraclass correlation: 0.83-0.92). Concurrent validity was demonstrated through highly significant relationships with relevant domains of the MOS SF-36 and the EQ- 5D-5L. Assessment of known-groups validity identified significant differences in Ox-PAQ scores among the three conditions included in the survey. Results suggest that the Ox-PAQ is a valid and reliable measure of participation and activity. The measure will now be validated in a range of further conditions, and additional properties, such as responsiveness, will also be assessed in the next phase of the instrument's development.

  7. 75 FR 22770 - Gary E. Hall and Rita Hall; Notice of Availability of Environmental Assessment (United States)


    ... project and concludes that exempting the project from licensing, with appropriate environmental measures.... 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...

  8. Air temperature gradient in large industrial hall (United States)

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


    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.

  9. Extrinsic spin Hall effect in graphene (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.

  10. Field theory approach to quantum hall effect

    International Nuclear Information System (INIS)

    Cabo, A.; Chaichian, M.


    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

  11. The Oxford Participation and Activities Questionnaire: study protocol. (United States)

    Morley, David; Dummett, Sarah; Kelly, Laura; Dawson, Jill; Fitzpatrick, Ray; Jenkinson, Crispin


    With an ageing population and increasing demands on health and social care services, there is growing importance attached to the management of long-term conditions, including maximizing the cost-effectiveness of treatments. In line with this, there is increasing emphasis on the need to keep people both active and participating in daily life. Consequently, it is essential that well developed and validated instruments that can meaningfully assess levels of participation and activity are widely available. Current measures, however, are largely focused on disability and rehabilitation, and there is no measure of activity or participation for generic use that fully meets the standards set by regulatory bodies such as the US Food and Drug Administration. Here we detail a protocol for the development and validation of a new patient-reported outcome measure (PROM) for assessment of participation and activity in people experiencing a variety of health conditions, ie, the Oxford Participation and Activities Questionnaire (Ox-PAQ). The stages incorporated in its development are entirely in line with current regulations and represent best practice in the development of PROMs. Development of the Ox-PAQ is theoretically grounded in the World Health Organization International Classification of Functioning, Disability, and Health. The project incorporates a new strategy of engaging with stakeholders from the outset in an attempt to identify those characteristics of PROMs considered most important to a range of potential users. Items will be generated through interviews with patients from a range of conditions. Pretesting of the instrument will be via cognitive interviews and focus groups. A postal survey will be conducted, with data subject to factor and Rasch analysis in order to identify appropriate dimensions and redundant items. Reliability will be assessed by Cronbach's alpha and item-total correlations. A second, large-scale postal survey will follow, with the Ox-PAQ being

  12. Shielding consideration for the SSCL experimental halls

    International Nuclear Information System (INIS)

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


    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

  13. Enhanced Performance of Cylindrical Hall Thrusters

    International Nuclear Information System (INIS)

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


    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

  14. Prototype dining hall energy efficiency study

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  15. A NACURH White Paper on Residence Hall Government. (United States)

    Wyatt, Kevin W.; Stoner, Kenneth L.


    Presents a white paper on residence hall government, summarizing fundamental principles in organizing and maintaining a residence hall association on campus. These include determining needs, identifying support, obtaining income, ensuring effective leadership, and developing system maintenance. (JAC)

  16. The Refined Lecture Hall Theorem via Abacus Diagrams


    Bradford, Laura; Harris, Meredith; Jones, Brant; Komarinski, Alex; Matson, Carly; O'Shea, Edwin


    Bousquet-M\\'elou & Eriksson's lecture hall theorem generalizes Euler's celebrated distinct-odd partition theorem. We present an elementary and transparent proof of a refined version of the lecture hall theorem using a simple bijection involving abacus diagrams.

  17. 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 ...

  18. Ion instabilities in the Hall plasma

    International Nuclear Information System (INIS)

    Gordeev, A.V.; Grechina, A.V.


    Instabilities of the Hall plasma are investigated to study the properties of plasma with small ion number per unit length, taking into account ion dynamics and electron mass finiteness. The availability of a universal mechanism resulting in a high two-stream instability with maximum increment of (ω Hi ω He ) 1/2 order is shown

  19. Judicious Leadership for Residence Hall Living. (United States)

    Gathercoal, Forrest

    This book presents a theory of judicious leadership for residence hall management that advocates the creation of an ethical and educational perspective based on the U.S. Bill of Rights. It argues that by recognizing college students' citizenship rights, providing them an opportunity to experience individual liberties, and helping them to…

  20. Pseudospin anisotropy classification of quantum Hall ferromagnets

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Tomáš; MacDonald, A. H.


    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

  1. Anomalous Hall conductivity: Local orbitals approach

    Czech Academy of Sciences Publication Activity Database

    Středa, Pavel


    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. Intrinsic anomalous Hall effect and local polarizabilities

    Czech Academy of Sciences Publication Activity Database

    Středa, Pavel; Jonckheere, T.


    Roč. 82, č. 11 (2010), 113303/1-113303/4 ISSN 1098-0121 R&D Projects: GA ČR GA202/08/0551 Institutional research plan: CEZ:AV0Z10100521 Keywords : orbital polarization momentum * Berry phase correction * anomalous Hall effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.772, year: 2010

  3. Surprises from the spin Hall effect

    Czech Academy of Sciences Publication Activity Database

    Sinova, Jairo; Jungwirth, Tomáš


    Roč. 70, č. 7 (2017), s. 39-42 ISSN 0031-9228 Institutional support: RVO:68378271 Keywords : spintronics * spin Hall effect * magnetic recording Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 4.188, year: 2016

  4. Chapin Hall Projects and Publications. Autumn 1999. (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…

  5. Anomalous Hall effect in disordered multiband metals

    Czech Academy of Sciences Publication Activity Database

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


    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

  6. Individualization in a Lecture Hall Setting. (United States)

    Halyard, Rebecca A.

    A two-quarter Human Anatomy and Physiology course for health-science students has been developed which incorporates the principles of individualization while maintaining the lecture hall setting. The lecture method contributes the following components to the course: (1) no special equipment or supplies; (2) personal interaction between instructor…

  7. line wear debris hall effect sensor

    African Journals Online (AJOL)



    Jul 2, 2013 ... environmental monitoring/control, use of low noise electronic components and method of opposing environmental ... Keywords: Hall Effect, sensor, noise reduction, hysteresis, temperature dependent drift, stability, full scale deflection, ... must conform to available standards and the characteristics must be.

  8. Spin Hall effect on a noncommutative space

    International Nuclear Information System (INIS)

    Ma Kai; Dulat, Sayipjamal


    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.

  9. Reliability and validity of the Oxford Happiness Inventory among university students in Iran. (United States)

    Liaghatdar, Mohammad Javad; Jafari, Ebrahim; Abedi, Mohammad Reza; Samiee, Fatemeh


    The aim of the present study was to examine the internal reliability, content validity, construct validity, and concurrent validity of the Persian translation/Farsi version of the Oxford Happiness Inventory. The Oxford Happiness Inventory and Fordyce Happiness Inventory were completed by a sample of 727 Iranian university students. Findings confirmed the internal reliability, construct, and concurrent validity of the Oxford Happiness Inventory. Thus, it can be recommended for use as a trait-measure of happiness among Iranian samples.

  10. Inertial-Hall effect: the influence of rotation on the Hall conductivity

    Directory of Open Access Journals (Sweden)

    Julio E. Brandão


    Full Text Available Inertial effects play an important role in classical mechanics but have been largely overlooked in quantum mechanics. Nevertheless, the analogy between inertial forces on mass particles and electromagnetic forces on charged particles is not new. In this paper, we consider a rotating non-interacting planar two-dimensional electron gas with a perpendicular uniform magnetic field and investigate the effects of the rotation in the Hall conductivity. The rotation introduces a shift and a split in the Landau levels. As a consequence of the break of the degeneracy, the counting of the states fully occupied below the Fermi energy increases, tuning the Hall quantization steps. The rotation also changes the quantum Hall plateau widths. Additionally, we find the Hall quantization steps as a function of rotation at a fixed value of the magnetic field.

  11. Chiral heat transport in driven quantum Hall and spin Hall edge states (United States)

    Arrachea, Liliana; Fradkin, Eduardo


    We consider a model for an edge state of electronic systems in the quantum Hall regime with filling ν=1 as well as in the quantum spin Hall regime. In both cases the system is in contact with two reservoirs by tunneling at point contacts. Both systems are locally driven by applying an ac voltage in one of the contacts. By weakly coupling them to a third reservoir, the transport of the generated heat is studied in two different ways: i) when the third reservoir acts as a thermometer the local temperature is sensed, and ii) when the third reservoir acts as a voltage probe the time-dependent local voltage is sensed. Our results indicate a chiral propagation of the heat along the edge in the quantum Hall case and in the quantum spin Hall case (if the injected electrons are spin polarized). The temperature profile shows that electrons along the edge thermalize with the closest upstream reservoir.

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

    NARCIS (Netherlands)

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


    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

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

    Indian Academy of Sciences (India)

    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 conduction ...

  14. 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 ...

  15. Diagnostics Systems for Permanent Hall Thrusters Development (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

  16. G.-M. de Schryver (Editor). Oxford Bilingual School Dictionary: Zulu ...

    African Journals Online (AJOL)


    The Oxford Bilingual School Dictionary: Zulu and English (henceforth OZSD) is the latest addition to the bidirectional English–isiZulu bilingual dictionary market and is based on the same successful and prize-winning formula used for the Oxford Northern Sotho School Dictionary (ONSD) published in 2007. One could state ...

  17. G.-M. de Schryver et al. (Eds.). Oxford Bilingual School Dictionary ...

    African Journals Online (AJOL)


    Oxford University Press Southern Africa has added the Oxford Bilingual School. Dictionary: IsiXhosa and English to its impressively developing series of bilingual school dictionaries involving English and other official languages of South. Africa. The series already has similar dictionaries in other languages namely. isiZulu ...

  18. Translation, cross-culturally adaptation and validation of the Danish version of Oxford Hip Score (OHS)

    DEFF Research Database (Denmark)

    Paulsen, Aksel

    .80-0.95. The average limits of agreement was -0.05-0.06. The internal consistency was found to be high with a Cronbachs alpha of 0.99, and the average inter-item correlation was 0.88. Conclusions: The Danish translation of the Oxford Hip Score is a valid and reliable patient reported outcome measurement instrument......Objective: The Oxford Hip Score is a patient reported outcome questionnaire designed to assess pain and function in patients undergoing total hip arthroplaty (THA). The Oxford Hip Score is valid, reliable and consistent, and different language versions have been developed. Since...... there was no properly translated, adapted and validated Danish language version available, a translation to Danish, cross-culturally adaptation and validation of the Danish Oxford Hip Score was warranted. Material and Methods: We translated and cross-culturally adapted the Oxford Hip Score into Danish, in accordance...

  19. The ``cinquefoil" resistive/Hall measurement geometry (United States)

    Koon, Daniel W.


    This talk begins by analyzing the charge transport weighting functions -- the sensitivity of resistive and Hall measurements to local macroscopic inhomogeneities -- of bridge-shaped transport specimens. As expected, such measurements sample only that region of the specimen between the central voltage electrodes, in the limit of narrow current channels connected by even narrower arms to the voltage electrodes. The bridge geometry has a few advantages over the van der Pauw cloverleaf geometry -- including ease in zeroing out the null-field Hall voltage -- but also some disadvantages. The talk concludes with an analysis of a hybrid geometry, the “cinquefoil” or five-leafed clover, which combines the best features of both.

  20. Induced radioisotopes in a linac treatment hall. (United States)

    Vega-Carrillo, Héctor René; de Leon-Martinez, Héctor Asael; Rivera-Perez, Esteban; Luis Benites-Rengifo, Jorge; Gallego, Eduardo; Lorente, Alfredo


    When linacs operate above 8MV an undesirable neutron field is produced whose spectrum has three main components: the direct spectrum due to those neutrons leaking out from the linac head, the scattered spectrum due to neutrons produced in the head that collides with the nuclei in the head losing energy and the third spectrum due to room-return effect. The third category of spectrum has mainly epithermal and thermal neutrons being constant at any location in the treatment hall. These neutrons induce activation in the linac components, the concrete walls and in the patient body. Here the induced radioisotopes have been identified in concrete samples located in the hall and in one of the wedges. The identification has been carried out using a gamma-ray spectrometer. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Stuart Hall and Cultural Studies, circa 1983

    Directory of Open Access Journals (Sweden)

    Ann Curthoys


    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.

  2. Theory of fractional quantum hall effect

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.


    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)

  3. Music hall Markneukirchen; Musikhalle in Markneukirchen

    Energy Technology Data Exchange (ETDEWEB)



    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)

  4. Acoustics in rock and pop music halls

    DEFF Research Database (Denmark)

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


    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...... frequency sounds are typically highly amplified, they play an important role in the subjective ratings and the 63-Hz-band must be included in objective measurements and recommendations....

  5. SPS beam to the West Hall

    CERN Multimedia

    CERN PhotoLab


    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.

  6. SERVIR Town Hall - Connecting Space to Village (United States)

    Limaye, Ashutosh S.; Searby, Nancy D.; Irwin, Daniel; Albers, Cerese


    SERVIR, a joint NASA-USAID project, strives to improve environmental decision making through the use of Earth observations, models, and geospatial technology innovations. SERVIR connects these assets with the needs of end users in Mesoamerica, East Africa, and Hindu Kush-Himalaya regions. This Town Hall meeting will engage the AGU community by exploring examples of connecting Space to Village with SERVIR science applications.

  7. Viscoelastic-electromagnetism and Hall viscosity


    Hidaka, Yoshimasa; Hirono, Yuji; Kimura, Taro; Minami, Yuki


    We introduce a kind of electromagnetism, which we call viscoelastic-electromagnetism, to investigate viscoelastic transport phenomena. It is shown that Cartan's formalism of general relativity is essential for viscoelastic theory, and then the corresponding electric and magnetic fields are regarded as a velocity gradient and a Burgers vector density, respectively. As an application of this formalism, the Streda formula for the Hall viscosity is obtained.

  8. Acoustics in rock and pop music halls

    DEFF Research Database (Denmark)

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


    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 D...... frequency sounds are typically highly amplified, they play an important role in the subjective ratings and the 63-Hz-band must be included in objective measurements and recommendations....

  9. Industrial steel hall with bridge grane


    Jurejevčič, Nejc


    In introduction this diploma thesis describes all main characteristics of (single block)? industrial steel hall with bridge crane. Load arrangement on the supporting structure which covers general actions (snow load and wind action), self-weight and dynamic load of bridge crane was designed with moment resisting frame in transverse direction and frame with concentric diagonal bracing in longitudinual direction. Actions induced by crane bridge was considered in design of runway beam. Steel hal...

  10. An ultra-low temperature scanning Hall probe microscope for magnetic imaging below 40 mK


    Karci Ozgur; Piatek Julian O.; Jorba Pau; Dede Munir; Ronnow Henrik M.; Oral Ahmet


    We describe the design of a low temperature scanning Hall probe microscope (SHPM) for a dilution refrigerator system. A detachable SHPM head with 25.4 mm OD and 200 mm length is integrated at the end of the mixing chamber base plate of the dilution refrigerator insert (Oxford Instruments, Kelvinox MX-400) by means of a dedicated docking station. It is also possible to use this detachable SHPM head with a variable temperature insert (VTI) for 2 K-300 K operations. A microfabricated 1 mu m size...

  11. Anode Fall Formation in a Hall Thruster

    International Nuclear Information System (INIS)

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


    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

  12. Hall viscosity: A link between quantum Hall systems, plasmas and liquid crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lingam, Manasvi, E-mail:


    In this Letter, the assumption of two simple postulates is shown to give rise to a Hall viscosity term via an action principle formulation. The rationale behind the two postulates is clearly delineated, and the connections to an intrinsic angular momentum are emphasized. By employing this methodology, it is shown that Hall viscosity appears in a wide range of fields, and the interconnectedness of quantum Hall systems, plasmas and nematic liquid crystals is hypothesized. Potential avenues for experimental and theoretical work arising from this cross-fertilization are also indicated. - Highlights: • Connections between simple 2D fluid models in different fields of physics presented. • Structure emerges via varied physical mechanisms driven by internal angular momentum. • Properties of these models such as Casimirs, equilibria and stability are analyzed.

  13. Commemorative Symposium on the Hall Effect and its Applications

    CERN Document Server

    Westgate, C


    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...

  14. Nonlinearity in the effect of an inhomogeneous Hall angle (United States)

    Koon, Daniel W.


    The differential equation for the electric potential in a conducting material with an inhomogeneous Hall angle is extended to the large-field limit. This equation is solved for a square specimen, using a successive over-relaxation [SOR] technique for matrices of up to 101x101 size, and the Hall weighting function -- the effect of local pointlike perturbations on the measured Hall angle -- is calculated as both the unperturbed Hall angle, θH, and the perturbation, δθH, exceed the linear, small angle limit. Preliminary results show that the Hall angle varies by no more than 5% if both | θH |<1 and | δθH |<1. Thus, previously calculated results for the Hall weighting function can be used for most materials in all but the most extreme magnetic fields.

  15. Annotated catalogue of the types of Braconidae (Hymenoptera) in the Oxford University Museum

    NARCIS (Netherlands)

    Achterberg, van C.; O'Toole, C.


    An annotated catalogue of the types of Braconidae in the Hope Entomological Collections, University Museum, Oxford, is given. The following new combinations are proposed: Aleiodes rothneyi (Shenefelt, 1975); Aniphiaulax agraensis (Cameron, 1897); Balcemena ruficollis (Cameron, 1899); Bicarinibracon

  16. The Oxford Classification predictors of chronic kidney disease in pediatric patients with IgA nephropathy

    Directory of Open Access Journals (Sweden)

    Rafaela C.G. Fabiano


    Conclusion: This is the first cohort study that evaluated the predictive role of the Oxford Classification in pediatric patients with IgAN from South America. Endocapillary proliferation was the unique pathological feature that independently predicted renal outcome.

  17. Performance evaluation of roundabouts for traffic delay and crash reductions in Oxford, MS. (United States)


    Due to increased traffic volume, congestion, and capacity limitations, two roundabouts have been constructed on South Lamar : Boulevard ramp intersections with MS Highway 6 in Oxford, MS. Roundabouts replaced the existing signalized intersection : on...

  18. Basic Instrumentation for Hall A at Jefferson Jab

    International Nuclear Information System (INIS)

    The Jefferson Lab Hall A Collaboration


    The instrumentation in Hall A at the JLab was designed to study electro- and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. A collaboration of approximately 50 institutions from all over the world has actively contributed and participated in the design, construction and commissioning of the Hall A instrumentation. The basic Hall A equipment is described herein

  19. Oxford NOTECHS II: a modified theatre team non-technical skills scoring system. (United States)

    Robertson, Eleanor R; Hadi, Mohammed; Morgan, Lauren J; Pickering, Sharon P; Collins, Gary; New, Steve; Griffin, Damian; Griffin, Damien; McCulloch, Peter; Catchpole, Ken C


    We previously developed and validated the Oxford NOTECHS rating system for evaluating the non-technical skills of an entire operating theatre team. Experience with the scale identified the need for greater discrimination between levels of performance within the normal range. We report here the development of a modified scale (Oxford NOTECHS II) to facilitate this. The new measure uses an eight-point instead of a four point scale to measure each dimension of non-technical skills, and begins with a default rating of 6 for each element. We evaluated this new scale in 297 operations at five NHS sites in four surgical specialities. Measures of theatre process reliability (glitch count) and compliance with the WHO surgical safety checklist were scored contemporaneously, and relationships with NOTECHS II scores explored. Mean team Oxford NOTECHS II scores was 73.39 (range 37-92). The means for surgical, anaesthetic and nursing sub-teams were 24.61 (IQR 23, 27); 24.22 (IQR 23, 26) and 24.55 (IQR 23, 26). Oxford NOTECHS II showed good inter-rater reliability between human factors and clinical observers in each of the four domains. Teams with high WHO compliance had higher mean Oxford NOTECHS II scores (74.5) than those with low compliance (71.1) (p = 0.010). We observed only a weak correlation between Oxford NOTECHS II scores and glitch count; r = -0.26 (95% CI -0.36 to -0.15). Oxford NOTECHS II scores did not vary significantly between 5 different hospital sites, but a significant difference was seen between specialities (p = 0.001). Oxford NOTECHS II provides good discrimination between teams while retaining reliability and correlation with other measures of teamwork performance, and is not confounded by technical performance. It is therefore suitable for combined use with a technical performance scale to provide a global description of operating theatre team performance.

  20. Precision of single-engage micro Hall effect measurements

    DEFF Research Database (Denmark)

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


    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......]. 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...

  1. High Efficiency Hall Thruster Discharge Power Converter Project (United States)

    National Aeronautics and Space Administration — Busek leveraged previous, internally sponsored, high power, Hall thruster discharge converter development which allowed it to design, build, and test new printed...

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

    Directory of Open Access Journals (Sweden)

    Lee SangHun


    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.

  3. Neutronic design of MYRRHA reactor hall shielding

    Directory of Open Access Journals (Sweden)

    Celik Yurdunaz


    Full Text Available The lateral shielding of a 600 MeV proton linear accelerator beam line in the MYRRHA reactor hall has been assessed using neutronic calculations by the MCNPX code complemented with analytical predictions. Continuous beam losses were considered to define the required shielding thickness that meets the requirements for the dose rate limits. Required shielding thicknesses were investigated from the viewpoint of accidental full beam loss as well as beam loss on collimator. The results confirm that the required shielding thicknesses are highly sensitive to the spatial shape of the beam and strongly divergent beam losses. Therefore shielding barrier should be designed according to the more conservative assumptions.

  4. Fractional quantization and the quantum hall effect

    International Nuclear Information System (INIS)

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


    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

  5. Optically induced Hall effect in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Idrish Miah, M; Gray, E Mac A, E-mail: [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)


    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.

  6. Hall conductivity for two dimensional magnetic systems

    International Nuclear Information System (INIS)

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


    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)

  7. Chiral heat transport in driven quantum Hall and quantum spin Hall edge states (United States)

    Arrachea, Liliana; Fradkin, Eduardo


    We consider a model for an edge state of electronic systems in the quantum Hall regime with filling ν=1 and in the quantum spin Hall regime. In both cases, the system is in contact with two reservoirs by tunneling at point contacts. Both systems are locally driven by applying an ac voltage in one of the contacts. By weakly coupling them to a third reservoir, the transport of the generated heat is studied in two different ways: (i) when the third reservoir acts as a thermometer, the local temperature is sensed and (ii) when the third reservoir acts as a voltage probe, the time-dependent local voltage is sensed. Our results indicate a chiral propagation of the heat along the edge in the quantum Hall and in the quantum spin Hall cases (if the injected electrons are spin polarized). We also show that a analogous picture is obtained if instead of heating by ac driving the system is put in contact to a stationary reservoir at a higher temperature. In both cases, the temperature profile shows that the electrons along the edge thermalize with the closest “upstream” reservoir.

  8. A Yankee at Oxford: John William Draper at the British Association for the Advancement of Science at Oxford, 30 June 1860 (United States)

    Ungureanu, James C.


    This paper contributes to the revisionist historiography on the legendary encounter between Samuel Wilberforce and Thomas Henry Huxley at the 1860 meeting in Oxford of the British Association for the Advancement of Science. It discusses the contents of a series of letters written by John William Draper and his family reflecting on his experience at that meeting. The letters have recently been rediscovered and have been neither published nor examined at full length. After a preliminary discussion on the historiography of the Oxford debate, the paper discloses the contents of the letters and then assesses them in the light of other contemporary accounts. The letters offer a nuanced reinterpretation of the event that supports the growing move towards a revisionist account. PMID:27386714

  9. How to Find Optimal National Model of Pension System: the Projection on Russia (Book Review: Barr, N. Pension reform: A short guide [Text] / N. Barr, P. Diamond. – Oxford : Oxford University Press, 2010. – 261 p.

    Directory of Open Access Journals (Sweden)

    Karen Avakovich Tumanyants


    Full Text Available How to Find Optimal National Model of Pension System: the Projection on Russia (Book Review: Barr, N. Pension reform: A short guide [Text] / N. Barr, P. Diamond. – Oxford : Oxford University Press, 2010. – 261 p.

  10. Cylindrical Hall Thrusters with Permanent Magnets

    International Nuclear Information System (INIS)

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


    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.

  11. Avalanche breakdown of the quantum hall effects

    CERN Document Server

    Komiyama, S


    Heat stability of two-dimensional electron gas (2DEG) systems in the integer quantum hall effect (IQHE) regime is discussed, and a heat instability is suggested to be the intrinsic mechanism behind the breakdown of the IQHE. Phenomenological argument is provided to suggest that the 2DEG system in the IQHE state becomes thermally unstable when the Hall electric field E sub y reaches a threshold value E sub b. Above E sub b , excited nonequilibrium electrons (holes), which are initially present in the conductor as the temperature fluctuation, are accelerated by E sub y and the 2DEG thereby undergoes a transition to a warm dissipative state. The critical field, E sub b , of this abrupt transition is theoretically estimated and shown to be in fare agreement with experimentally reported values. Consideration of the dynamics of electrons suggests that the transition is a process of avalanche electron-hole pair multiplication, in which a small number of non-equilibrium carriers, gains kinetic energy within a Landau ...

  12. Planar Hall Effect in Magnetic Conducting Oxides (United States)

    Akouala, Christer Rajiv

    Magnetic semiconductors are of interest for use in non-volatile memory device read heads, magnetoresistive sensors, and other spintronic devices. Research in this area has mostly focused on generating magnetic semiconductors by doping non-magnetic semiconductors with magnetic ions. This work has instead taken advantage of the defectinduced magnetism in several semiconducting oxides. The planar Hall effect (PHE) is a phenomenon that can be used for characterizing magnetic semiconductors. Along with the anisotropic magnetoresistance (AMR), PHE has the potential to provide insight into the mechanism for magnetic behavior in magnetic conducting oxide thin films that are undoped. PHE has therefore been studied in undoped ZnO, SnO2, CdO, and CuO using magnetotransport and magnetometry techniques. The measurements included both AMR and PHE taken at various temperatures from 300 to 4.2K in a Quantum Design Physical Property Measurement System (QD-PPMS) and in a custom-built magnetotransport set-up. Complementary measurements include XRD, and resistivity measurements. Resistivity vs. temperature, Hall effect, and magnetoresistance measurements were performed in the PPMS. Magnetic hysteresis and magnetization vs. temperature were acquired using a Quantum Design Magnetic Properties Measurement System (QD-MPMS).

  13. Undulator Hall Air Temperature Fault Scenarios

    International Nuclear Information System (INIS)

    Sevilla, J.


    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.

  14. An ultra-low temperature scanning Hall probe microscope for magnetic imaging below 40 mK (United States)

    Karcı, Özgür; Piatek, Julian O.; Jorba, Pau; Dede, Münir; Rønnow, Henrik M.; Oral, Ahmet


    We describe the design of a low temperature scanning Hall probe microscope (SHPM) for a dilution refrigerator system. A detachable SHPM head with 25.4 mm OD and 200 mm length is integrated at the end of the mixing chamber base plate of the dilution refrigerator insert (Oxford Instruments, Kelvinox MX-400) by means of a dedicated docking station. It is also possible to use this detachable SHPM head with a variable temperature insert (VTI) for 2 K-300 K operations. A microfabricated 1μm size Hall sensor (GaAs/AlGaAs) with integrated scanning tunneling microscopy tip was used for magnetic imaging. The field sensitivity of the Hall sensor was better than 1 mG/√Hz at 1 kHz bandwidth at 4 K. Both the domain structure and topography of LiHoF4, which is a transverse-field Ising model ferromagnet which orders below TC = 1.53 K, were imaged simultaneously below 40 mK.

  15. Quantum Hall samples prepared by helium-ion implantation

    International Nuclear Information System (INIS)

    Bruus, H.; Lindelof, P.E.; Veje, E.


    We have produced GaAs/GaAlAs heterostructure based quantum Hall samples with a wide range of electron mobilities using ion implantation. The purpose has been to optimize the samples for use in metrology. We have in particular studied the critical current and the non-ohmic behavior of our samples in the vicinity of a quantum Hall plateau. (orig.)

  16. A Business-Oriented Student Program: Residence Hall Stores. (United States)

    Valerio, Vance R.


    Describes a residence hall store program which provides prepackaged food and snacks to students at Marquette University. Results of a survey of 21 colleges which have residence hall stores revealed primarily informal organizations. Stores can be a successful student development technique which teaches principles of small-business management. (JAC)

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

    Indian Academy of Sciences (India)

    topological insulators [10,11] and quantum Hall metals [12–21] are the other major solid- state systems that currently need proper and consistent formulations to understand their electronic properties, regardless of whether these systems have the potential for future technological marvels. Here, we shall derive the trial Hall ...

  18. Mary E. Hall: Dawn of the Professional School Librarian (United States)

    Alto, Teresa


    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…

  19. Role of the Hall Effect on the Magnetorotational Instability (United States)

    Bejarano, Cecilia; Gómez, Daniel

    Within the framework of magnetohydrodynamics, the Hall effect might become significant either in fully ionized low density plasmas or in cold plasmas with a low ionization fraction. We address the role of the Hall current in the development of the magnetorotational instability. The instability criterion and the instability growth rate are derived from a one-dimensional model.

  20. Pair spectrometer hodoscope for Hall D at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, F.; Hutton, C.; Sitnikov, A. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Somov, A., E-mail: [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Somov, S.; Tolstukhin, I. [National Research Nuclear University MEPhI, Moscow (Russian Federation)


    We present the design of the pair spectrometer hodoscope fabricated at Jefferson Lab and installed in the experimental Hall D. The hodoscope consists of thin scintillator tiles; the light from each tile is collected using wave-length shifting fibers and detected using a Hamamatsu silicon photomultiplier. Light collection was measured using relativistic electrons produced in the tagger area of the experimental Hall B.

  1. Critical current in the Integral Quantum Hall Effect

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.


    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)

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

    Tao, Y.


    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.

  3. Stuart Hall on Racism and the Importance of Diasporic Thinking (United States)

    Rizvi, Fazal


    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…

  4. Useful Pedagogical Applications of the Classical Hall Effect (United States)

    Houari, Ahmed


    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…

  5. Bulk Versus Edge in the Quantum Hall Effect


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


    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.

  6. Unconventional quantum Hall effect in Floquet topological insulators

    KAUST Repository

    Tahir, M.


    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.

  7. Accurate micro Hall effect measurements on scribe line pads

    DEFF Research Database (Denmark)

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


    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......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...... accurate in less than a minute. Measurements are performed on shallow trench isolation patterned silicon wafers to verify the results from the Monte Carlo method....

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

    Directory of Open Access Journals (Sweden)

    Vlassis N. Petoussis


    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.

  9. EL CROWN HALL. CONTEXTO Y PROYECTO / The Crown Hall. Context and project

    Directory of Open Access Journals (Sweden)

    José Santatecla Fayós


    Full Text Available RESUMEN El artículo enmarca el edificio del Crown Hall en el contexto docente y arquitectónico de Mies van der Rohe. Revisa sus inicios en la Bauhaus con su primera intervención en un espacio docente para la Bauhaus de Berlín en 1932, así como su marcha a Estados Unidos, los planteamientos arquitectónicos del campus del IIT y el proyecto del Crown Hall. El texto incide en el estudio del proceso proyectual del Crown Hall analizando la evolución de su concepción arquitectónica a través de las diferentes versiones del proyecto. Se constata la transición desde los primeros planteamientos arquitectónicos de los edificios del campus del IIT proyectados por Mies hacia el planteamiento del gran espacio unitario del Crown Hall. Este proyecto se puede entender desde la creciente importancia de la estructura, la claridad constructiva y el manejo del acero y vidrio como únicos materiales de la imagen del edificio y el carácter flexible y unitario del espacio. Finalmente se hace referencia al concepto del “espacio universal” en la arquitectura de Mies, como un concepto abstracto que supera los de flexibilidad de uso o unidad espacial, insinuando, a modo de reflexión, las principales variables que definirían el espacio universal miesiano. SUMMARY The article showcases the Crown Hall building in the educational and architectural context of Mies van der Rohe. It reviews his beginnings in the Bauhaus with his first intervention in an educational space for the Bauhaus of Berlin in 1932, as well as his sojourn to the United States, and the architectural approaches to the IIT campus and the Crown Hall project. The text touches on the study of the planning process for the Crown Hall, analysing the evolution of its architectural conception, through the different versions of the project. The article covers the transition from the first architectural approaches for the IIT campus buildings, planned by Mies, to the approach of the large unitary space

  10. Concept of Operating Indoor Skiing Halls with

    DEFF Research Database (Denmark)

    Paul, Joachim


    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....

  11. Magnetic circuit for hall effect plasma accelerator (United States)

    Manzella, David H. (Inventor); Jacobson, David T. (Inventor); Jankovsky, Robert S. (Inventor); Hofer, Richard (Inventor); Peterson, Peter (Inventor)


    A Hall effect plasma accelerator includes inner and outer electromagnets, circumferentially surrounding the inner electromagnet along a thruster centerline axis and separated therefrom, inner and outer magnetic conductors, in physical connection with their respective inner and outer electromagnets, with the inner magnetic conductor having a mostly circular shape and the outer magnetic conductor having a mostly annular shape, a discharge chamber, located between the inner and outer magnetic conductors, a magnetically conducting back plate, in magnetic contact with the inner and outer magnetic conductors, and a combined anode electrode/gaseous propellant distributor, located at a bottom portion of the discharge chamber. The inner and outer electromagnets, the inner and outer magnetic conductors and the magnetically conducting back plate form a magnetic circuit that produces a magnetic field that is largely axial and radially symmetric with respect to the thruster centerline.

  12. Frequency spectrum of Calder Hall reactor noise

    International Nuclear Information System (INIS)

    Cummins, J.D.


    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)

  13. Numerical investigation of a Hall thruster plasma

    International Nuclear Information System (INIS)

    Roy, Subrata; Pandey, B.P.


    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

  14. Gauge Physics of Spin Hall Effect (United States)

    Tan, Seng Ghee; Jalil, Mansoor B. A.; Ho, Cong Son; Siu, Zhuobin; Murakami, Shuichi


    Spin Hall effect (SHE) has been discussed in the context of Kubo formulation, geometric physics, spin orbit force, and numerous semi-classical treatments. It can be confusing if the different pictures have partial or overlapping claims of contribution to the SHE. In this article, we present a gauge-theoretic, time-momentum elucidation, which provides a general SHE equation of motion, that unifies under one theoretical framework, all contributions of SHE conductivity due to the kinetic, the spin orbit force (Yang-Mills), and the geometric (Murakami-Fujita) effects. Our work puts right an ambiguity surrounding previously partial treatments involving the Kubo, semiclassical, Berry curvatures, or the spin orbit force. Our full treatment shows the Rashba 2DEG SHE conductivity to be instead of -, and Rashba heavy hole instead of -. This renewed treatment suggests a need to re-derive and re-calculate previously studied SHE conductivity.

  15. Fractional quantum Hall effect in optical lattices

    International Nuclear Information System (INIS)

    Hafezi, M.; Demler, E.; Lukin, M. D.; Soerensen, A. S.


    We analyze a recently proposed method to create fractional quantum Hall (FQH) states of atoms confined in optical lattices [A. Soerensen et al., Phys. Rev. Lett. 94, 086803 (2005)]. Extending the previous work, we investigate conditions under which the FQH effect can be achieved for bosons on a lattice with an effective magnetic field and finite on-site interaction. Furthermore, we characterize the ground state in such systems by calculating Chern numbers which can provide direct signatures of topological order and explore regimes where the characterization in terms of wave-function overlap fails. We also discuss various issues which are relevant for the practical realization of such FQH states with ultracold atoms in an optical lattice, including the presence of a long-range dipole interaction which can improve the energy gap and stabilize the ground state. We also investigate a detection technique based on Bragg spectroscopy to probe these systems in an experimental realization

  16. Long term effects on potential repository sites: the alteration of the Lower Oxford Clay during weathering

    International Nuclear Information System (INIS)

    Milowdowski, A.E.; Bloodworth, A.J.; Wilmot, R.D.


    The report is one of a short series describing work carried out to investigate the long-term effects of various geological processes on the performance of both shallow and deep repositories for low and intermediate-level radioactive wastes. This paper deals with the alteration as a result of weathering of the Lower Oxford Clay, a potential host rock for shallow disposal of wastes. A description of the Lower Oxford Clay is given, along with the weathering of argillaceous rocks. Investigations of the weathering at the Elstow Storage Depot are described, as well as the implications for radioactive waste disposal. (U.K.)

  17. Oxford NOTECHS II: a modified theatre team non-technical skills scoring system.

    Directory of Open Access Journals (Sweden)

    Eleanor R Robertson

    Full Text Available BACKGROUND: We previously developed and validated the Oxford NOTECHS rating system for evaluating the non-technical skills of an entire operating theatre team. Experience with the scale identified the need for greater discrimination between levels of performance within the normal range. We report here the development of a modified scale (Oxford NOTECHS II to facilitate this. The new measure uses an eight-point instead of a four point scale to measure each dimension of non-technical skills, and begins with a default rating of 6 for each element. We evaluated this new scale in 297 operations at five NHS sites in four surgical specialities. Measures of theatre process reliability (glitch count and compliance with the WHO surgical safety checklist were scored contemporaneously, and relationships with NOTECHS II scores explored. RESULTS: Mean team Oxford NOTECHS II scores was 73.39 (range 37-92. The means for surgical, anaesthetic and nursing sub-teams were 24.61 (IQR 23, 27; 24.22 (IQR 23, 26 and 24.55 (IQR 23, 26. Oxford NOTECHS II showed good inter-rater reliability between human factors and clinical observers in each of the four domains. Teams with high WHO compliance had higher mean Oxford NOTECHS II scores (74.5 than those with low compliance (71.1 (p = 0.010. We observed only a weak correlation between Oxford NOTECHS II scores and glitch count; r = -0.26 (95% CI -0.36 to -0.15. Oxford NOTECHS II scores did not vary significantly between 5 different hospital sites, but a significant difference was seen between specialities (p = 0.001. CONCLUSIONS: Oxford NOTECHS II provides good discrimination between teams while retaining reliability and correlation with other measures of teamwork performance, and is not confounded by technical performance. It is therefore suitable for combined use with a technical performance scale to provide a global description of operating theatre team performance.

  18. Nonadiabatic effects in the Quantum Hall regime

    International Nuclear Information System (INIS)

    Page, D.A.; Brown, E.


    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

  19. Repeatability of the Oxford Foot Model for Kinematic Gait Analysis of the Foot and Ankle

    NARCIS (Netherlands)

    van Hoeve, S.; Vos, J.; Weijers, P.; Verbruggen, J.; Willems, P.; Poeze, M.; Meijer, K.


    INTRODUCTION: Kinematic gait analysis via the multi-segmental Oxford foot model (OFM) may be a valuable addition to the biomechanical examination of the foot and ankle. The aim of this study is to assess the repeatability of the OFM in healthy subjects. METHODS: Nine healthy subjects, without a

  20. The Oxford Handbook of the Archaeology and Anthropology of Hunter-Gatherers

    NARCIS (Netherlands)

    Cummings, Vicky; Jordan, Peter; Zvelebil, Marek


    For more than a century, the study of hunting and gathering societies has been central to the development of both archaeology and anthropology as academic disciplines, and has also generated widespread public interest and debate. The Oxford Handbook of the Archaeology and Anthropology of

  1. Lessons from the Round Table: Literacy Professionals Find Common Ground in Oxford (United States)

    Paterson, Wendy A.


    In July, 2006, Literacy Professionals from across the United States met at Lady Margaret College in Oxford University to discuss research and practice in the teaching of reading and the expansion of literacy. In a tense national climate, reading researchers refer to contrasting theories of teaching reading as "the reading wars," but at…

  2. A.P. Cowie (Editor). The Oxford History of English Lexicography ...

    African Journals Online (AJOL)

    Riette Ruthven

    According to the blurb, The Oxford History of English Lexicography (volumes I–II) presents 'the fullest account yet published of the lexicography of English from its origins in medieval glosses, through its rapid development in the eighteenth century, to a fully-established high-tech industry that is as reliant as ever on learning ...

  3. Developing a Structured Teaching Plan for Psychiatry Tutors at Oxford University (United States)

    Al-Taiar, Hasanen


    Purpose: The purpose of this thesis was to examine the teaching ways I undertook in teaching medical students and to examine the use of a structured teaching plan for the academic and clinical tutors in psychiatry. The teaching plan was developed for use, initially by Oxford University Academic tutors at the Department of Psychiatry. In addition,…

  4. The Why, What, and Impact of GPA at Oxford Brookes University (United States)

    Andrews, Matthew


    This paper examines the introduction at Oxford Brookes University of a Grade Point Average (GPA) scheme alongside the traditional honours degree classification. It considers the reasons for the introduction of GPA, the way in which the scheme was implemented, and offers an insight into the impact of GPA at Brookes. Finally, the paper considers…

  5. Transport measurements of GaAs/AlGaAs devices in the ``anti-Hall-bar within a Hall bar" geometry (United States)

    Kriisa, Annika; Mani, Ramesh


    Hall effect measurements are often carried out in the Hall geometry, which is a thin rectangular plate with current and Hall voltage contacts at the external boundary. The motivation of this study is to further understand the impact on Hall effect when a hole is inserted inside the Hall geometry. One way on conducting this investigation is to superimpose an ``anti-Hall bar'' inside the standard Hall bar, where the anti Hall bar is actually the hole inside the Hall device with contacts on the inside boundary of this hole. This configuration is thought to generate an ordinary Hall effect within the interior boundary. One believes that it might also be possible to simultaneously realize multiple independent Hall effects by injecting multiple currents into the multiply connected device [1]. We have experimentally studied the Hall effect in the doubly connected ``anti-Hall bar within a Hall bar'' geometry fabricated out of the GaAs/AlGaAs semiconductor system, and convey the results in this presentation. [4pt] [1] R. G. Mani and K. von Klitzing, Z. Phys. B 92, 335 (1993).

  6. Hall conductance and topological invariant for open systems. (United States)

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


    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.

  7. Acoustic investigations of concert halls for rock music

    DEFF Research Database (Denmark)

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


    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...

  8. Effective Field Theory of Fractional Quantized Hall Nematics

    Energy Technology Data Exchange (ETDEWEB)

    Mulligan, Michael; /MIT, LNS; Nayak, Chetan; /Station Q, UCSB; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC


    We present a Landau-Ginzburg theory for a fractional quantized Hall nematic state and the transition to it from an isotropic fractional quantum Hall state. This justifies Lifshitz-Chern-Simons theory - which is shown to be its dual - on a more microscopic basis and enables us to compute a ground state wave function in the symmetry-broken phase. In such a state of matter, the Hall resistance remains quantized while the longitudinal DC resistivity due to thermally-excited quasiparticles is anisotropic. We interpret recent experiments at Landau level filling factor {nu} = 7/3 in terms of our theory.

  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.


    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

  10. Anomalous Hall effect in Fe/Gd bilayers

    KAUST Repository

    Xu, W. J.


    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. Materials for giant spin Hall effect devices (United States)

    Jayanthinarasimham, Avyaya

    Studies presented in this thesis are an effort to control the growth of beta W and explore the in-plane current induced effects in a beta W and CoFeB bilayer. Physical vapor deposited W films beyond 5 nm transform from beta to the stable bulk alpha phase. beta W films with 5 nm thickness when integrated with the other films for large scale fabrication presents a small process window for etch and deposition errors. Also, CoFeB on W does not generate perpendicular magnetic anisotropy (PMA) even when it is capped with MgOjTa(Capping) layers. The beta W with larger thickness process window and a CoFeB with PMA deposited on top of W is necessary for an ideal functioning spin Hall effect (SHE) device. This thesis will focus on overcoming the above mentioned challenges. 2 sccm of O2 gas was introduced during the growth of beta W, this resulted in thicker films with beta W. If a large amount of O2 was introduced, it resulted in complete oxidation and loss of crystallinity. Thus an optimum amount of oxygen is necessary. However, introducing O2 during the deposition can effect other metals present on the wafer, which is not ideal. N2 was utilized to achieve thicker beta W films. Upon introducing N with similar concentration of O, it lead to amorphization of W, thus revealing a kinetic control. A pulsed N2 of 1 sccm at 2-second period was used to kinetically control the growth of beta W. Both the techniques were able to grow beta W from 5 nm up to 20 nm thick films. Films with N-assisted growth exhibited lower resistance and higher metallic character. 1 nm Ta, Mo and CoFe were used as insert layers between beta W and CoFeB to induce PMA. 1 nm Mo insert layer and 5 nm Mo under layer have largely different interfaces with CoFeB even when annealed in ultra high vacuum (UHV) environment. Thus, 1 nm Mo layer does not show any PMA. The CoFe insert layer adds to the bulk anisotropy and dominates the interface anisotropy, and does not lead to any PMA. The 1 nm Ta insert exhibits

  12. Direct Drive Hall Thruster System Development (United States)

    Hoskins, W. Andrew; Homiak, Daniel; Cassady, R. Joseph; Kerslake, Tom; Peterson, Todd; Ferguson, Dale; Snyder, Dave; Mikellides, Ioannis; Jongeward, Gary; Schneider, Todd


    The sta:us of development of a Direct Drive Ha!! Thruster System is presented. 13 the first part. a s:udy of the impacts to spacecraft systems and mass benefits of a direct-drive architecture is reviewed. The study initially examines four cases of SPT-100 and BPT-4000 Hall thrusters used for north-south station keeping on an EXPRESS-like geosynchronous spacecraft and for primary propulsion for a Deep Space- 1 based science spacecraft. The study is also extended the impact of direct drive on orbit raising for higher power geosynchronous spacecraft and on other deep space missions as a function of power and delta velocity. The major system considerations for accommodating a direct drive Hall thruster are discussed, including array regulation, system grounding, distribution of power to the spacecraft bus, and interactions between current-voltage characteristics for the arrays and thrusters. The mass benefit analysis shows that, for the initial cases, up to 42 kg of dry mass savings is attributable directly to changes in the propulsion hardware. When projected mass impacts of operating the arrays and the electric power system at 300V are included, up to 63 kg is saved for the four initial cases. Adoption of high voltage lithium ion battery technology is projected to further improve these savings. Orbit raising of higher powered geosynchronous spacecraft, is the mission for which direct drive provides the most benefit, allowing higher efficiency electric orbit raising to be accomplished in a limited period of time, as well as nearly eliminating significant power processing heat rejection mass. The total increase in useful payload to orbit ranges up to 278 kg for a 25 kW spacecraft, launched from an Atlas IIA. For deep space missions, direct drive is found to be most applicable to higher power missions with delta velocities up to several km/s , typical of several Discovery-class missions. In the second part, the status of development of direct drive propulsion power

  13. Hall penetration of a magnetic field into a uniform conductor

    International Nuclear Information System (INIS)

    Gordeev, A.V.


    It is shown that magnetic fields can convect into a uniform conductor due to the breakdown of quasineutrality associated with the Hall field. The nonlinear equation describing this process is derived and studied. 9 refs., 2 figs

  14. Quantum Hall Ferroelectrics and Nematics in Multivalley Systems (United States)

    Sodemann, Inti; Zhu, Zheng; Fu, Liang


    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.

  15. High Throughput Hall Thruster for Small Spacecraft, Phase II (United States)

    National Aeronautics and Space Administration — Busek is developing a high throughput nominal 100-W Hall Effect Thruster. This device is well sized for spacecraft ranging in size from several tens of kilograms to...

  16. Performance of an 8 kW Hall Thruster

    National Research Council Canada - National Science Library

    Pote, B


    ... in addition to high Isp for station keeping. To satisfy these requirements, Busek Co. embarked on the development of a novel, high power Hall thruster, capable of efficient operation over a broad range of Isp and thrust...

  17. Preliminary Study of Arcjet Neutralization of Hall Thruster Clusters (Postprint)

    National Research Council Canada - National Science Library

    Walker, Quentin E; Cappelli, Mark A; Hargus, William A


    ... to a surrogate anode from the plume of low power arcjets operating on hydrogen and helium, and then demonstrate the first successful operation of a low power Hall thruster-arcjet neutralizer package...

  18. Measuring the Hall weighting function for square and cloverleaf geometries (United States)

    Scherschligt, Julia K.; Koon, Daniel W.


    We have directly measured the Hall weighting function—the sensitivity of a four-wire Hall measurement to the position of macroscopic inhomogeneities in Hall angle—for both a square shaped and a cloverleaf specimen. Comparison with the measured resistivity weighting function for a square geometry [D. W. Koon and W. K. Chan, Rev. Sci. Instrum. 69, 12 (1998)] proves that the two measurements sample the same specimen differently. For Hall measurements on both a square and a cloverleaf, the function is nonnegative with its maximum in the center and its minimum of zero at the edges of the square. Converting a square into a cloverleaf is shown to dramatically focus the measurement process onto a much smaller portion of the specimen. While our results agree qualitatively with theory, details are washed out, owing to the finite size of the magnetic probe used.

  19. What do you measure when you measure the Hall effect? (United States)

    Koon, D. W.; Knickerbocker, C. J.


    A formalism for calculating the sensitivity of Hall measurements to local inhomogeneities of the sample material or the magnetic field is developed. This Hall weighting function g(x,y) is calculated for various placements of current and voltage probes on square and circular laminar samples. Unlike the resistivity weighting function, it is nonnegative throughout the entire sample, provided all probes lie at the edge of the sample. Singularities arise in the Hall weighting function near the current and voltage probes except in the case where these probes are located at the corners of a square. Implications of the results for cross, clover, and bridge samples, and the implications of our results for metal-insulator transition and quantum Hall studies are discussed.

  20. Iodine Hall Thruster for Space Exploration, Phase I (United States)

    National Aeronautics and Space Administration — Busek Co Inc proposes to develop a high power (high thrust) electric propulsion system featuring an iodine fueled Hall Effect Thruster (HET). The system to be...

  1. 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.


    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

  2. Magnesium Hall Thruster for Solar System Exploration, Phase II (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...

  3. Hall Mobility of Amorphous Ge2Sb2Te5

    National Research Council Canada - National Science Library

    Baily, S. A; Emin, David; Li, Heng


    The electrical conductivity, Seebeck coefficient, and Hall coefficient of 3 micron thick films of amorphous Ge2Sb2Te5 have been measured as functions of temperature from room temperature down to as low as 200 K...

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

    National Research Council Canada - National Science Library

    Averin, Dmitri


    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...

  5. Low Temperature Hall Measurements of Neutron Irradiated Silicon Carbide

    National Research Council Canada - National Science Library

    Bonavita, Ange1o


    .... No features suggesting annealing were found below a temperature of 340K. Temperature dependant Hall effect measurements were taken over a range of 100K to 340K recording resistivity, carrier densities, and mobility...

  6. Simultaneous effects of Hall and convective conditions on peristaltic ...

    Indian Academy of Sciences (India)

    stress fluid in an inclined asymmetric channel with convective conditions. Soret and Dufour and Hall effects are taken into account. Analysis has been carried out in a wave frame of reference. Expressions for velocity, pressure gradient, temperature ...

  7. High Input Voltage Hall Thruster Discharge Converter, Phase I (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...

  8. A High Performance Cathode Heater for Hall Thrusters, Phase I (United States)

    National Aeronautics and Space Administration — High current hollow cathodes are the baseline electron source for next generation high power Hall thrusters. Currently for electron sources providing current levels...

  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


    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 (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. Positive operator valued measures and the quantum Monty Hall problem

    Directory of Open Access Journals (Sweden)

    Claudia Zander


    Full Text Available A quantum version of the Monty Hall problem, based upon the Positive Operator Valued Measures (POVM formalism, is proposed. It is shown that basic normalization and symmetry arguments lead univocally to the associated POVM elements, and that the classical probabilities associated with the Monty Hall scenario are recovered for a natural choice of the measurement operators.Uma visão quântica do problema Monty Hall é proposta baseada no formalismo das Medidas Avaliadas do Operador Positivo (POVM. Demonstra-se que os argumentos de normalização básica e simetria levam de maneira inequívoca para elementos associados a POVM e que as probabilidades clássicas associadas ao cenário Monty Hall são recuperadas para uma escolha natural de medidas operadoras.

  12. High Throughput Hall Thruster for Small Spacecraft Project (United States)

    National Aeronautics and Space Administration — Busek Co. Inc. proposes to develop a high throughput, nominal 100 W Hall Effect Thruster (HET). This HET will be sized for small spacecraft (< 180 kg), including...

  13. Imaging of Low Compressibility Strips in the Quantum Hall Liquid


    Finkelstein, G.; Glicofridis, P. I.; Tessmer, S. H.; Ashoori, R. C.; Melloch, M. R.


    Using Subsurface Charge Accumulation scanning microscopy we image strips of low compressibility corresponding to several integer Quantum Hall filling factors. We study in detail the strips at Landau level filling factors $\

  14. Observation of the anomalous Hall effect in GaAs

    International Nuclear Information System (INIS)

    Miah, M Idrish


    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

  15. 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)


    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.

  16. Iodine Hall Thruster for Space Exploration, Phase II (United States)

    National Aeronautics and Space Administration — In the Phase I program, Busek Co. Inc. tested an existing Hall thruster, the BHT-8000, on iodine propellant. The thruster was fed by a high flow iodine feed system,...

  17. 2D Electrostatic Potential Solver for Hall Thruster Simulation

    National Research Council Canada - National Science Library

    Koo, Justin W


    ...) 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...

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

    CERN Document Server

    Fujita, Shigeji; Godoy, Salvador


    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

  19. Magnesium Hall Thruster for Solar System Exploration, Phase I (United States)

    National Aeronautics and Space Administration — Busek proposes to prove the feasibility of a Mg Hall effect thruster system that would open the door for In-Situ Resource Utilization (ISRU) based solar system...

  20. Theology amongst the sciences: A personal view from the University of Oxford

    Directory of Open Access Journals (Sweden)

    Susan E. Gillingham


    Full Text Available The paper focuses on two individuals who have each made a seminal contribution to the debates between theology and the sciences in Oxford - Charles Darwin (in the mid�19th century, and Richard Dawkins (from the 1990s to the present day. It introduces Darwin by way of a more personal and visual view from Worcester College Chapel. The restoration of the chapel took place at about the same time as the debates between Huxley and Wilberforce in the Oxford University Museum over Charles Darwin�s On the Origin of the Species. The first part of the paper then traces these debates back: first to an earlier period of disputation represented by Galileo Galilei (c. 1564�1642, and then to a period of greater accommodation represented by Isaac Newton (1643�1727. Darwin represents a third, more controversial, stage. The paper then looks at a fourth period, from the mid�20th century onwards, which is marked by more eirenical attempts to demarcate science and theology by seeing the former again as asking the �how� questions and the latter, the �why� questions. It then focuses on a fifth, more disputatious stage, which was initiated by Richard Dawkins, professor in the Public Understanding of Science until 2008. Professor Dawkins challenges the idea that theology cannot be studied, because its focus is a non-existent object, �God�.The second part of the paper looks at various Oxford projects and Oxford theologians who have risen to this contemporary challenge. They include the work of the Ian Ramsey Centre; Justin Barret�s and John Trigg�s joint � 2 million project, supported by the John Templeton foundation, which examines scientific ideas about religion and the mind; Richard Harries, Bishop of Oxford from 1987 to 2006, who has conducted a number of media interviews with Richard Dawkins; Keith Ward, who has written several books engaging not only with Dawkins but is also the Cambridge Professor of Mathematics, Stephen Hawking; and

  1. Aerosol trace metals, particle morphology and total gaseous mercury in the atmosphere of Oxford, UK (United States)

    Witt, M. L. I.; Meheran, N.; Mather, T. A.; de Hoog, J. C. M.; Pyle, D. M.


    An investigation of atmospheric trace metals was conducted in Oxford, UK, a small city ˜60 miles northwest of London, in 2007 and 2008. Concentrations of Sr, Mo, Cd, Pb, V, Cr, Mn, Fe, Co, Ni, Cu and Zn in aerosol were measured in bulk and size segregated samples. In addition, total gaseous mercury (TGM) concentrations were monitored semi-continuously by cold vapour-atomic fluorescence spectroscopy. Metal concentrations in Oxford were intermediate between previously reported levels of UK rural and urban areas for most metals studied and levels of Cd, Ni and Pb were within European guidelines. Metal concentrations appeared to be influenced by higher traffic volume on a timescale of hours. The influence of traffic on the aerosols was also suggested by the observation of carbonaceous particles via scanning electron microscopy (SEM). Air mass back trajectories suggest air masses arriving in Oxford from London and mainland Europe contained the highest metal concentrations. Aerosol samples collected over Bonfire Weekend, a period of intense firework use and lighting of bonfires in the UK, showed metal concentrations 6-46 times higher than at other times. Strontium, a tracer of firework release, was present at higher concentrations and showed a change in its size distribution from the coarse to fine mode over Bonfire Weekend. The presence of an abundance of spherical Sr particles was also confirmed in SEM images. The average TGM concentration in Oxford was 3.17 ng m -3 (st. dev. 1.59) with values recorded between 1.32 and 23.2 ng m -3. This is a higher average value than reported from nearby rural locations, although during periods when air was arriving from the west, similar concentrations to these rural areas were seen in Oxford. Comparison to meteorological data suggests that TGM in Oxford's air is highest when wind is arriving from the east/southeast. This may be due to emissions from London/mainland Europe with a possible contribution from emissions from a local

  2. The integer quantum hall effect revisited

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  3. Hall MHD reconnection in cometary magnetotail

    International Nuclear Information System (INIS)

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


    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

  4. Brand new hall in the main building

    CERN Multimedia

    Corinne Pralavorio


    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...

  5. Following the Path Blazed by Jan Hall (United States)

    Hollberg, Leo

    It was a great pleasure to gather with friends in August 2004 for the symposium honoring Jan Hall and celebrating his 70th birthday, and this book provides a unique opportunity to record some words commemorating Jan's incredible contributions to science and to our lives. At best, my recollections are a faded, myopic snapshot of some events that come to mind after many years of association with Jan. Reflecting on the years that have passed since I first entered Jan's lab, I see that many things have changed, technology has advanced (mostly for the better), the world has evolved in dramatic and significant ways (some good and some not), and I have grown older (but unfortunately not wiser as one might have hoped). Nonetheless, after many years, I find myself still following the path pointed out by Jan's visions and investing most of my productive time and energy working as a scientist trying to get atoms, lasers, electronics, (and the institutional bureaucracy that comes along with them) to work in some kind of harmony…

  6. Acoustics in Halls for Speech and Music (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.

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

    African Journals Online (AJOL)

    I address what I call 'the number issue', which is raised by our ordinary talk and beliefs about certain social groups and institutions, and I take the Hallé orchestra as my example. The number issue is that of whether the Hallé is one individual or several individuals. I observe that if one holds that it is one individual, one faces ...

  8. Energy Spectrum and Quantum Hall Effect in Twisted Bilayer Graphene


    Moon, Pilkyung; Koshino, Mikito


    We investigate the electronic spectra and quantum Hall effect in twisted bilayer graphenes with various rotation angles under magnetic fields, using a model rigorously including the interlayer interaction. We describe the spectral evolution from discrete Landau levels in the weak field regime to the fractal band structure in the strong field regime, and estimate the quantized Hall conductivity for each single gap. In weak magnetic fields, the low-energy conduction band of the twisted bilayer ...

  9. The Hall Effect in Hydrided Rare Earth Films (United States)

    Koon, D. W.; Azofeifa, D. E.; Clark, N.

    We describe two new techniques for measuring the Hall effect in capped rare earth films during hydriding. In one, we simultaneously measure resistivity and the Hall coefficient for a rare earth film covered with four different thicknesses of Pd, recovering the charge transport quantities for both materials. In the second technique, we replace Pd with Mn as the covering layer. We will present results from both techniques.

  10. Spin and Isospin: Exotic Order in Quantum Hall Ferromagnets (United States)

    Girvin, Steven M.

    Quantum mechanics is a strange business, and the quantum physics of strongly correlated many-electron systems can be stranger still. Good examples are the various quantum Hall effects. They are among the most remarkable many-body quantum phenomena discovered in the second half of the 20th century, comparable in intellectual import to superconductivity and superfluidity. The quantum Hall effects are an extremely rich set of phenomena with deep and truly fundamental theoretical implications...

  11. The Quantum Hall Effect: Novel Excitations and Broken Symmetries


    Girvin, Steven M.


    These pedagogical lecture notes present a general introduction to most aspects of the integer and fractional quantum Hall effects. This is followed by an extensive discussion of quantum Hall ferromagnetism, both for spins in single-layer systems and `pseudospins' in double-layer systems. The effective field theories describing various broken symmetry states and `skyrmion' and `meron' spin textures are derived and discussed in some detail. Pedagogical presentations on Berry phases and lowest L...

  12. High-performance LED luminaire for sports hall (United States)

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


    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.

  13. Project of industrial hall with a bridge crane


    Ambrožič, Klemen


    In graduation thesis design of steel industrial hall with a bridge crane is performed. The first chapter contains technical report of the structure. Followed by the second chapter, which analyzes bridge crane and crane track. The influences of bridge crane are determined. These influences are considered for design of the crane track, fatigue check and displacements of the crane supporting structure. Fatigue check contains basic detail. The third chapter contains analysis of the hall supportin...

  14. Iodine Plasma Species Measurements in a Hall Effect Thruster Plume (United States)


    from a 200 W Hall Effect Thruster fueled by iodine vapor was analyzed. The plasma source included a laboratory propellant feed system and a laboratory...distribution is unlimited Abstract • The plasma plume from a 200 W Hall Effect Thruster fueled by iodine vapor was analyzed. • The plasma source... pressure with I2 – Plume divergence lower with I2 – Dimers (I2+) measured at beam centroid (a few %) Iodine Xenon 7 Distribution A: Approved for public

  15. Anisotropic intrinsic spin Hall effect in quantum wires

    International Nuclear Information System (INIS)

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


    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)

  16. Spin Hall effect and spin swapping in diffusive superconductors (United States)

    Espedal, Camilla; Lange, Peter; Sadjina, Severin; Mal'shukov, A. G.; Brataas, Arne


    We consider the spin-orbit-induced spin Hall effect and spin swapping in diffusive superconductors. By employing the nonequilibrium Keldysh Green's function technique in the quasiclassical approximation, we derive coupled transport equations for the spectral spin and particle distributions and for the energy density in the elastic scattering regime. We compute four contributions to the spin Hall conductivity, namely, skew scattering, side jump, anomalous velocity, and the Yafet contribution. The reduced density of states in the superconductor causes a renormalization of the spin Hall angle. We demonstrate that all four of these contributions to the spin Hall conductivity are renormalized in the same way in the superconducting state. In its simplest manifestation, spin swapping transforms a primary spin current into a secondary spin current with swapped current and polarization directions. We find that the spin-swapping coefficient is not explicitly but only implicitly affected by the superconducting gap through the renormalized diffusion coefficients. We discuss experimental consequences for measurements of the (inverse) spin Hall effect and spin swapping in four-terminal geometries. In our geometry, below the superconducting transition temperature, the spin-swapping signal is increased an order of magnitude while changes in the (inverse) spin Hall signal are moderate.

  17. Shear-driven Instabilities in Hall-magnetohydrodynamic Plasmas (United States)

    Bejarano, Cecilia; Gómez, Daniel O.; Brandenburg, Axel


    The large-scale dynamics of plasmas is well described within the framework of magnetohydrodynamics (MHD). However, whenever the ion density of the plasma becomes sufficiently low, the Hall effect is likely to become important. The role of the Hall effect has been studied in several astrophysical plasma processes, such as magnetic reconnection, magnetic dynamo, MHD turbulence, or MHD instabilities. In particular, the development of small-scale instabilities is essential to understand the transport properties in a number of astrophysical plasmas. The magneto-rotational instability (MRI), which takes place in differentially rotating accretion disks embedded in relatively weak magnetic fields, is just one example. The influence of the large-scale velocity flows on small-scale instabilities is often approximated by a linear shear flow. In this paper, we quantitatively study the role of the Hall effect on plasmas embedded in large-scale shear flows. More precisely, we show that an instability develops when the Hall effect is present, which we therefore term as the Hall magneto-shear instability. As a particular case, we recover the so-called MRI and quantitatively assess the role of the Hall effect on its development and evolution.

  18. High-Coverage Long Read DNA Sequencing with the Oxford Nanopore MinION


    Jain, Miten


    Nanopore sequencing was conceived in 1989 by Dave Deamer (UCSC). Over two decades of development from research laboratories and, later on, Oxford Nanopore Technologies resulted in the MinION nanopore sequencer. This work describes the developments in MinION nanopore sequencing and software, and technical milestones achieved since the MinION’s release in 2014. These developments include establishing DNA reads that exceed 200 kb+ lengths and direct, simultaneous detection of nucleotide modifica...

  19. Rubidium-strontium ages from the Oxford Lake-Knee Lake greenstone belt, northern Manitoba

    International Nuclear Information System (INIS)

    Clark, G.S.; Cheung, S.-P.


    Rb-Sr whole-rock ages have been determined for rocks from the Oxford Lake-Knee Lake-Gods Lake geenstone belt in the Superior Province of northeastern Manitoba. The age of the Magill Lake Pluton is 2455 +- 35 Ma(lambda 87 Rb = 1.42 x 10 -11 yr -1 ), with an initial 87 Sr/ 86 Sr ratio of 0.7078 +- 0.0043. This granite stock intrudes the Oxford Lake Group, so it is post-tectonic and probably related to the second, weaker stage of metamorphism. The age of the Bayly Lake Pluton is 2424 +- 74 Ma, with an initial 87 Sr/ 86 Sr ratio of 0.7029 +- 0.0001. This granodioritic batholith complex does not intrude the Oxford Lake Group. It is syn-tectonic and metamorphosed. The age of volcanic rocks of the Hayes River Group, from Goose Lake (30 km south of Gods Lake Narrows), is 2680 +- 125 Ma, with an initial 87 Sr/ 86 Sr ratio of 0.7014 +- 0.0009. The age for the Magill Lake and Bayly Lake Plutons can be interpreted as the minimum ages of granite intrusion in the area. The age for the Hayes River Group volcanic rocks is consistent with Rb-Sr ages of volcanic rocks from other Archean greenstone belts within the northwestern Superior Province. (auth)

  20. Oxford Grading Scale vs manometer for assessment of pelvic floor strength in nulliparous sports students. (United States)

    Da Roza, T; Mascarenhas, T; Araujo, M; Trindade, V; Jorge, R Natal


    To compare pelvic floor muscle strength in nulliparous sports students measured using the modified Oxford Grading Scale and a Peritron manometer; and to compare the manometric measurements between continent and incontinent subjects. Cross-sectional study. All subjects were evaluated twice on the same day; first by vaginal digital examination and subsequently by vaginal pressure using a Peritron manometer. Forty-three nulliparous female sports students [mean age 21 (standard deviation 4) years] from the Sports Faculty of the University of Porto. This study found a significant moderate correlation between the Oxford Grading Scale score and peak pressure on manometry (r=0.646, P=0.002). Mean maximal strength for the entire group was 70.4cmH2O (range 21 to 115cmH2O). Out of 43 subjects, 37% (n=16) demonstrated signs of incontinence. On manometry, no significant differences were found in vaginal resting pressure or peak pressure between the continent and incontinent groups. There was moderate correlation between peak pressure on manometry and the Oxford Grading Scale score. Peritron manometer measurements of pelvic floor muscle contractions showed no significant differences in vaginal resting pressure and peak pressure in continent and incontinent subjects. Copyright © 2012 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

  1. Living and Learning: "Does Residence Hall Roommate Placement of Traditional Freshman Students at MSOE Effect Their Satisfaction with the Residence Halls?" (United States)

    Breese, William Ellis, II


    The purpose of this study is to examine if residence hall roommate placement of traditional freshman students at MSOE affects their satisfaction with the residence halls. The idea behind this study is that if residence hall roommate placement is done purposefully, with the participation of incoming freshmen through appropriate placement…

  2. Seville City Hall Chapter Room ceiling decoration

    Directory of Open Access Journals (Sweden)

    Robador, M. D.


    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

  3. Concert halls with strong lateral reflections enhance musical dynamics. (United States)

    Pätynen, Jukka; Tervo, Sakari; Robinson, Philip W; Lokki, Tapio


    One of the most thrilling cultural experiences is to hear live symphony-orchestra music build up from a whispering passage to a monumental fortissimo. The impact of such a crescendo has been thought to depend only on the musicians' skill, but here we show that interactions between the concert-hall acoustics and listeners' hearing also play a major role in musical dynamics. These interactions contribute to the shoebox-type concert hall's established success, but little prior research has been devoted to dynamic expression in this three-part transmission chain as a complete system. More forceful orchestral playing disproportionately excites high frequency harmonics more than those near the note's fundamental. This effect results in not only more sound energy, but also a different tone color. The concert hall transmits this sound, and the room geometry defines from which directions acoustic reflections arrive at the listener. Binaural directional hearing emphasizes high frequencies more when sound arrives from the sides of the head rather than from the median plane. Simultaneously, these same frequencies are emphasized by higher orchestral-playing dynamics. When the room geometry provides reflections from these directions, the perceived dynamic range is enhanced. Current room-acoustic evaluation methods assume linear behavior and thus neglect this effect. The hypothesis presented here is that the auditory excitation by reflections is emphasized with an orchestra forte most in concert halls with strong lateral reflections. The enhanced dynamic range provides an explanation for the success of rectangularly shaped concert-hall geometry.

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

    International Nuclear Information System (INIS)

    Kawasaki, Yukio


    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.)

  5. NASA HERMeS Hall Thruster Electrical Configuration Characterization (United States)

    Peterson, Peter Y.; Kamhawi, Hani; Huang, Wensheng; Yim, John; Herman, Daniel; Williams, George; Gilland, James; Hofer, Richard


    The NASA 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 paper describes the electrical configuration testing of the HERMeS TDU-1 Hall thruster in NASA Glenn Research Center's Vacuum Facility 5. The three electrical configurations examined were 1) thruster body tied to facility ground, 2) thruster floating, and 3) thruster body electrically tied to cathode common. The HERMeS TDU-1 Hall thruster was also configured with two different exit plane boundary conditions, dielectric and conducting, to examine the influence on the electrical configuration characterization.

  6. G. Stanley Hall, Child Study, and the American Public. (United States)

    Young, Jacy L


    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.

  7. Development of the Oxford Participation and Activities Questionnaire: constructing an item pool

    Directory of Open Access Journals (Sweden)

    Kelly L


    Full Text Available Laura Kelly, Crispin Jenkinson, Sarah Dummett, Jill Dawson, Ray Fitzpatrick, David Morley Health Services Research Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK Purpose: The Oxford Participation and Activities Questionnaire is a patient-reported outcome measure in development that is grounded on the World Health Organization International Classification of Functioning, Disability, and Health (ICF. The study reported here aimed to inform and generate an item pool for the new measure, which is specifically designed for the assessment of participation and activity in patients experiencing a range of health conditions. Methods: Items were informed through in-depth interviews conducted with 37 participants spanning a range of conditions. Interviews aimed to identify how their condition impacted their ability to participate in meaningful activities. Conditions included arthritis, cancer, chronic back pain, diabetes, motor neuron disease, multiple sclerosis, Parkinson's disease, and spinal cord injury. Transcripts were analyzed using the framework method. Statements relating to ICF themes were recast as questionnaire items and shown for review to an expert panel. Cognitive debrief interviews (n=13 were used to assess items for face and content validity. Results: ICF themes relevant to activities and participation in everyday life were explored, and a total of 222 items formed the initial item pool. This item pool was refined by the research team and 28 generic items were mapped onto all nine chapters of the ICF construct, detailing activity and participation. Cognitive interviewing confirmed the questionnaire instructions, items, and response options were acceptable to participants. Conclusion: Using a clear conceptual basis to inform item generation, 28 items have been identified as suitable to undergo further psychometric testing. A large-scale postal survey will follow in order to refine the instrument further and

  8. Inter-rater reliability study of the modified Oxford Grading Scale and the Peritron manometer. (United States)

    Ferreira, Cristine Homsi Jorge; Barbosa, Patrícia Brentegani; de Oliveira Souza, Flaviane; Antônio, Flávia Ignácio; Franco, Maíra Menezes; Bø, Kari


    To evaluate the inter-rater reliability of the modified Oxford Grading Scale and the Peritron manometer. All participants were evaluated twice, first by one examiner and 30 days later by a second examiner. Measurements of vaginal squeeze pressure were compared with the results from the palpation test. Nineteen women with a mean age of 23.7 years (range 21 to 28 years). Inter-rater reliability for vaginal palpation was fair (κ=0.33, 95% confidence interval 0.09 to 0.57). Using the Peritron manometer, the difference between examiners was less than 10cmH(2)O in 11 of the 19 (58%) cases. The palpation test did not differentiate between weak, moderate, good and strong muscle contractions. This study found fair inter-rater reliability for the modified Oxford Grading Scale and moderate inter-rater reliability for the Peritron manometer. The inter-rater reliability of vaginal squeeze pressure measurement using the Peritron manometer is acceptable and can be used in re-evaluations performed by different examiners in clinical practice. However, for research purposes, the ideal situation would be for a single examiner to assess and re-assess the subject. Vaginal palpation is important in the clinical assessment of correctness of a pelvic floor muscle contraction, but this study does not support the use of the modified Oxford Grading Scale as a reliable and valid method to measure and differentiate pelvic floor muscle strength. Copyright © 2010 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

  9. Turning points in physics, a series of lectures given at Oxford University in Trinity Term 1958

    CERN Document Server

    Blin-Stoyle, Roger John; Mendelssohn, Kurt; Temple, G; Waismann, F; Wilkinson, Denys Haigh; De Boer, J; Brinkman, H; Casimir, H B G


    Turning Points in Physics is a series of 1958 lectures presented at the Oxford University in Trinity Term. This six-chapter book highlights the interplay between assumptions, theories, and experimental discoveries in physics. The first chapter provides a brief introduction to the physical theory and field physics. The following two chapters cover the basic principles of quantum nature of matter and radiation, as well as the introduction of the probability concept in the field physics. The discussion then shifts to the theory of relativity and the fundamentals of cause and effect. The last chap

  10. New Instrumentation Reduces Operative Time in Medial Unicompartmental Knee Arthroplasty Using the Oxford Mobile Bearing Design

    Directory of Open Access Journals (Sweden)

    Keith Berend


    Full Text Available Redesigned instrumentation has become available for implantation of the Oxford Mobile Bearing Medial unicompartmental knee arthroplasty. To assess the benefit of these changes, we compared operative time of 200 Phase III and 176 Microplasty UKA done 2008-2011. An average time savings of 8.6 minutes was seen with the Microplasty design.  Additionally, the standard deviation in operative times, minimum and maximum operatives were lower in knees in which Microplasty instrumentation was utilized.  A 15% savings in operative time was seen with the new Microplasty instrumentation.

  11. The potential applications of a Stirling cycle cooler. Universiteit Oxford onderzoekt mogelijkheden Stirling-koeler

    Energy Technology Data Exchange (ETDEWEB)

    Hands, B.A. (Cryogenic Lab., Faculty of Engineering, Univ. of Oxford (United Kingdom))


    In 1978 the Cryogenic Laboratory of the Oxford University started a research program into the title cooling machine, based on a design of dr. Gordon Davey, who has been in charge of the research since that time. Already more than 20 Striling cycle coolers have been designed and constructed. Two of these machines are in operation trouble-free in space satellites, providing cooling for an infrared detector, which measures heat emissions. More applications are expected in the next few years (f.e. cooling of ceramic superconducting equipment, and so-called 'green' cooling for the industry and households). 5 figs., 6 refs.

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

    Directory of Open Access Journals (Sweden)

    Mehmet FENKLİ


    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

  13. Maximizing utilization of sport halls during peak hours

    DEFF Research Database (Denmark)

    Iversen, Evald Bundgård; Forsberg, Peter

    the number of participants 7.5 persons higher pr. activity compared to club activities. This implies that clubs during peak hours could include more participants. Another possibility to increase utilization is if the management of sport facilities forced sport clubs and other organisers to adapt......BACKGROUNDDuring peak hours (4.30pm-8pm) demand for timeslots in sport halls in Denmark are high and there are few timeslots available. Further, focus on how public resources are spent most efficient is increasing (Iversen, 2013). This makes it interesting to analyse how utilization could...... be increased during peak hours. DATA AND METHODOLOGYData is collected by observation of activities during two weeks on for example whether halls are used or not; the amount of playing field used; and number of participants (Iversen, 2012). Data on 1.331 activities in 36 sport halls across 4 municipalities have...

  14. Admittance of multiterminal quantum Hall conductors at kilohertz frequencies

    International Nuclear Information System (INIS)

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


    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

  15. 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: [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)


    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.

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

    KAUST Repository

    Saidaoui, Hamed Ben Mohamed


    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.

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

    International Nuclear Information System (INIS)

    Dolan, Brian P.


    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

  18. Topological Phase Transitions in the Photonic Spin Hall Effect (United States)

    Kort-Kamp, W. J. M.


    The recent synthesis of two-dimensional staggered materials opens up burgeoning opportunities to study optical spin-orbit interactions in semiconducting Dirac-like systems. We unveil topological phase transitions in the photonic spin Hall effect in the graphene family materials. It is shown that an external static electric field and a high frequency circularly polarized laser allow for active on-demand manipulation of electromagnetic beam shifts. The spin Hall effect of light presents a rich dependence with radiation degrees of freedom, and material properties, and features nontrivial topological properties. We discover that photonic Hall shifts are sensitive to spin and valley properties of the charge carriers, providing an unprecedented pathway to investigate spintronics and valleytronics in staggered 2D semiconductors.

  19. Overview of NASA Iodine Hall Thruster Propulsion System Development (United States)

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


    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.

  20. 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.


    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.

  1. Deep Mapping and Screen Tourism: The Oxford of Harry Potter and Inspector Morse

    Directory of Open Access Journals (Sweden)

    James Cateridge


    Full Text Available This article proposes that the experiences of screen tourists in Oxford help to create a theoretical “deep map” of the city which explores place through narrative. Building on the travel writing of William Least Heat-Moon and other recent work in the spatial humanities, two case studies of major screen tourism drivers are considered and analyzed. The British television drama Inspector Morse (1987–2000 explores the ambiguity of Oxford intellectualism through its central character. Morse’s love of high culture, especially music, provides suggestive additional layers for multimedia mapping, which are realized online through user-adapted Google Maps and geolocated images posted on the Flickr service. Harry Potter fans may not be “pure” or independent screen tourists, but they provide a wealth of data on their interactions with filming locations via social media such as Instagram. This data provides emotional as well as factual evidence, and is accumulating into an ever richer and deeper digital map of human experience.

  2. Oxford Nanopore sequencing, hybrid error correction, and de novo assembly of a eukaryotic genome. (United States)

    Goodwin, Sara; Gurtowski, James; Ethe-Sayers, Scott; Deshpande, Panchajanya; Schatz, Michael C; McCombie, W Richard


    Monitoring the progress of DNA molecules through a membrane pore has been postulated as a method for sequencing DNA for several decades. Recently, a nanopore-based sequencing instrument, the Oxford Nanopore MinION, has become available, and we used this for sequencing the Saccharomyces cerevisiae genome. To make use of these data, we developed a novel open-source hybrid error correction algorithm Nanocorr specifically for Oxford Nanopore reads, because existing packages were incapable of assembling the long read lengths (5-50 kbp) at such high error rates (between ∼5% and 40% error). With this new method, we were able to perform a hybrid error correction of the nanopore reads using complementary MiSeq data and produce a de novo assembly that is highly contiguous and accurate: The contig N50 length is more than ten times greater than an Illumina-only assembly (678 kb versus 59.9 kbp) and has >99.88% consensus identity when compared to the reference. Furthermore, the assembly with the long nanopore reads presents a much more complete representation of the features of the genome and correctly assembles gene cassettes, rRNAs, transposable elements, and other genomic features that were almost entirely absent in the Illumina-only assembly. © 2015 Goodwin et al.; Published by Cold Spring Harbor Laboratory Press.

  3. “To Live in Hearts We Leave Behind is Not to Die.” Remembrance Sunday at Pusey House, Oxford University, A Review of Worship at Oxford University

    Directory of Open Access Journals (Sweden)

    Peter L. Kraus


    Full Text Available In recent years, religious participation by students of all faiths at Universities in the United Kingdom has seen a steady increase in attendance. This brief essay is a case study of worship by members of the University Community at Pusey House at the University of Oxford, which reflects the trend. On a crisp fall, November day, the twenty-third Sunday after Trinity (8th of November 2015 I had the opportunity to attend services at Pusey House, Oxford on Remembrance Sunday while on sabbatical at The University of Oxford (St. Stephen’s House.

  4. Complex dynamics of the integer quantum Hall effect

    International Nuclear Information System (INIS)

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


    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

  5. Semiclassical droplet states in matrix quantum Hall effect

    International Nuclear Information System (INIS)

    Cappelli, Andrea; Rodriguez, Ivan D.


    We derive semiclassical ground state solutions that correspond to the quantum Hall states earlier found in the Maxwell-Chern-Simons matrix theory. They realize the Jain composite-fermion construction and their density is piecewise constant as that of phenomenological wave functions. These results support the matrix theory as a possible effective theory of the fractional Hall effect. A crucial role is played by the constraint limiting the degeneracy of matrix states: we find its explicit gauge invariant form and clarify its physical interpretation

  6. 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)


    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.

  7. Resistive and Hall weighting functions in three dimensions (United States)

    Koon, D. W.; Knickerbocker, C. J.


    The authors extend their study of the effect of macroscopic impurities on resistive and Hall measurements to include objects of finite thickness. The effect of such impurities is calculated for a series of rectangular parallelepipeds with two current and two voltage contacts on the corners of one square face. The weighting functions display singularities near these contacts, but these are shown to vanish in the two-dimensional limit, in agreement with previous results. Finally, it is shown that while Hall measurements principally sample the plane of the electrodes, resistivity measurements sample more of the interior of an object of finite thickness.

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

    International Nuclear Information System (INIS)

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


    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.)

  9. Complex scattering dynamics and the quantum Hall effects

    International Nuclear Information System (INIS)

    Trugman, S.A.


    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

  10. Quantum Hall ferromagnetism in II-VI based alloys (United States)

    Jaroszyski, J.; Andrearczyk, T.; Karczewski, G.; Wróbel, J.; Wojtowicz, T.; Papis, E.; Kamiska, E.; Piotrowska, A.; Popovi, Dragana; Dietl, T.


    The article reviews our recent studies on quantum Hall ferromagnetism (QHF) in diluted magnetic semiconductors. We carried out magnetoresistance studies on modulation-doped, gated heterostructures of (Cd,Mn)Te/(Cd,Mg)Te:I.We put into evidence the formation of Ising quantum Hall ferromagnet with Curie temperature TC as high as 2 K. QHF is manifested by anomalous magnetoresistance maxima. Moreover, magnitude of these spikes depends dramatically on the history of the sample, shows hysteresis when either magnetic field or gate voltage are swept, stretched-exponential time evolution characteristic of glassy systems, and strong Barkhausen noise. Our study suggests that these metastabilities stem from the slow dynamics of ferromagnetic domains.

  11. Spin Hall magnetoresistance in antiferromagnet/normal metal bilayers

    KAUST Repository

    Manchon, Aurelien


    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.

  12. Inverse spin Hall effect in Pt/(Ga,Mn)As (United States)

    Nakayama, H.; Chen, L.; Chang, H. W.; Ohno, H.; Matsukura, F.


    We investigate dc voltages under ferromagnetic resonance in a Pt/(Ga,Mn)As bilayer structure. A part of the observed dc voltage is shown to originate from the inverse spin Hall effect. The sign of the inverse spin Hall voltage is the same as that in Py/Pt bilayer structure, even though the stacking order of ferromagnetic and nonmagnetic layers is opposite to each other. The spin mixing conductance at the Pt/(Ga,Mn)As interface is determined to be of the order of 1019 m-2, which is about ten times greater than that of (Ga,Mn)As/p-GaAs.

  13. Magnetoresistance and Hall resistivity of semimetal WTe2 ultrathin flakes. (United States)

    Luo, Xin; Fang, Chi; Wan, Caihua; Cai, Jialin; Liu, Yong; Han, Xiufeng; Lu, Zhihong; Shi, Wenhua; Xiong, Rui; Zeng, Zhongming


    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.

  14. Wind tunnel tests of tent halls of different shape

    Directory of Open Access Journals (Sweden)

    Porowska Agnieszka


    Full Text Available Aerodynamic investigations of wind pressure distribution on the surfaces of models of tent halls were carried out in the boundary layer wind tunnel at the Cracow University of Technology. Four types of objects of different shapes and construction were tested. Although tent halls are significantly vulnerable with respect to the wind action, there is no information about pressure distribution on objects of such type in standards, codes and normalization documents. Obtained results indicate that it is necessary to take into account different configurations of wind action while designing of the analysed structures.

  15. Theory of spin Hall effect: extension of the Drude model. (United States)

    Chudnovsky, Eugene M


    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.

  16. Impact of external conditions on energy consumption in industrial halls (United States)

    Żabnieńśka-Góra, Alina


    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.

  17. Enhanced thermoelectric response in the fractional quantum Hall effect (United States)

    Roura-Bas, Pablo; Arrachea, Liliana; Fradkin, Eduardo


    We study the linear thermoelectric response of a quantum dot embedded in a constriction of a quantum Hall bar with fractional filling factors ν =1 /m within Laughlin series. We calculate the figure of merit Z T for the maximum efficiency at a fixed temperature difference. We find a significant enhancement of this quantity in the fractional filling in relation to the integer-filling case, which is a direct consequence of the fractionalization of the electron in the fractional quantum Hall state. We present simple theoretical expressions for the Onsager coefficients at low temperatures, which explicitly show that Z T and the Seebeck coefficient increase with m .

  18. Test-retest reliability, internal consistency, and construct validity of the Farsi version of the Oxford Happiness Inventory. (United States)

    Bayani, Ali Asghar


    This study examined the reliability and preliminary evidence for validity of a Farsi (Persian) version of the Oxford Happiness Inventory with 309 undergraduate students (161 women and 148 men). Participants completed the Farsi versions of four subscales of the Oxford Happiness Inventory, the Satisfaction with Life Scale, the Beck Depression Inventory, and the Depression-Happiness Scale. Analyses indicated that the Farsi version of the Oxford Happiness Scale has reliability as a measure of well-being and provided some preliminary evidence of construct validity.

  19. Oral contraceptive use and cancer: final report from the Oxford-Family Planning Association contraceptive study. (United States)

    Vessey, Martin; Yeates, David


    This analysis provides the final results on cancer incidence in relation to oral contraceptive (OC) use from the Oxford-Family Planning Association (Oxford-FPA) contraceptive study, which closed at the end of 2010. An additional 6 years of observation have been added since our last report and there has been an increase in the numbers of cancers of over 50% at seven of the sites considered. The Oxford-FPA study includes 17032 women aged 25-39 years recruited from 1968 to 1974 at contraceptive clinics in England and Scotland. These women were using OCs, a diaphragm or an intrauterine device. Information about cancer incidence among them has been collected from recruitment until closure of the study. OC use was not related to nonreproductive cancer. Breast cancer findings (1087 cases) were entirely negative; the rate ratio (RR) comparing ever users of OCs with never users was 1.0 [95% confidence interval (CI): 0.9-1.1]. Only two cases of cervical cancer have been added since our last report (total: 61 cases); the RR comparing ever use with never use is now 3.4 (95% CI: 1.6-8.9). The risk of this disease increases sharply with duration of OC use and declines steadily with interval since last OC use. OC use protects against both uterine body cancer (124 cases) and ovarian cancer (143 cases). The RRs comparing ever use with never use were 0.5 (95% CI: 0.3-0.7) and 0.5 (95% CI: 0.4-0.7), respectively. Protection against both these cancers increased with duration of OC use and waned with interval since last use, but an effect was still present 28 or more years after discontinuation. In our study, OC use had no effect on nonreproductive cancers or on breast cancer. The risk of cervical cancer was increased and that of uterine body cancer and ovarian cancer was decreased by OC use. All these effects increased with duration of use and declined with interval since last use. The beneficial effects of OC use on cancer outweighed the adverse effects. These findings should

  20. Study of the Accelerating Channel Wall Property Influence on the Hall Thruster Discharge Characteristics

    National Research Council Canada - National Science Library

    Vesselovzorov, Alexandre


    According to the work program and schedule there was developed the methodology of experiments on the discharge chamber material influence on the Hall thruster characteristics there was prepared Hall...

  1. Hall Effect Thruster for High Power Solar Electric Propulsion Technology Demonstration, Phase I (United States)

    National Aeronautics and Space Administration — Busek proposes to develop a flight version of a high power Hall Effect thruster. While numerous high power Hall Effect thrusters have been demonstrated in the...

  2. Measured Early Lateral Energy Fractions in Concert Halls and Opera Houses (United States)

    BARRON, M.


    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. Derivation of uranium residual radioactive material guidelines for the former Alba Craft Laboratory site, Oxford, Ohio

    International Nuclear Information System (INIS)

    Nimmagadda, M.; Faillace, E.; Yu, C.


    Residual radioactive material guidelines for uranium were derived for the former Alba Craft Laboratory site in Oxford, Ohio. This site has been identified for remedial action under the Formerly Utilized Sites Remedial Action Program (FUSRAP) of the US Department of Energy (DOE). Single nuclide and total uranium guidelines were derived on the basis of the requirement that the 50-year committed effective dose equivalent to a hypothetical individual who lives or works in the immediate vicinity of the former Alba Craft Laboratory site should not exceed a dose of 30 mrem/yr following remedial action for the current use and likely future use scenarios or a dose of 100 mrem/yr for less likely future use scenarios (Yu et al. 1993). The DOE residual radioactive material guideline computer code, RESRAD, which implements the methodology described in the DOE manual for implementing residual radioactive material guidelines, was used in this evaluation

  4. The Oxford Probe: an open access five-hole probe for aerodynamic measurements

    International Nuclear Information System (INIS)

    Hall, B F; Povey, T


    The Oxford Probe is an open access five-hole probe designed for experimental aerodynamic measurements. The open access probe can be manufactured by the end user via additive manufacturing (metal or plastic). The probe geometry, drawings, calibration maps, and software are available under a creative commons license. The purpose is to widen access to aerodynamic measurement techniques in education and research environments. There are many situations in which the open access probe will allow results of comparable accuracy to a well-calibrated commercial probe. We discuss the applications and limitations of the probe, and compare the calibration maps for 16 probes manufactured in different materials and at different scales, but with the same geometrical design. (paper)

  5. Validation of an Italian version of the Oxford happiness inventory in adolescence. (United States)

    Meleddu, Mauro; Guicciardi, Marco; Scalas, L Francesca; Fadda, Daniela


    An Italian adaptation of the Oxford Happiness Inventory was administered to 782 adolescents. Exploratory structural equation modeling (ESEM) was used to examine the first- and second-order factorial structure of the scale and its invariance across gender; internal consistency and construct validity were also investigated. ESEM underlined a 5-factor structure (mastery and self-fulfillment, satisfaction with life, vigor, social interest, and social cheerfulness) that measures positive psychological functioning. These dimensions form a single latent construct of general psychological well-being. The scale showed adequate internal consistency values and strong measurement invariance across gender. Finally, regarding convergent validity, both total scale and subscales were positively correlated with extraversion and self-esteem, were negatively correlated with neuroticism, and displayed no correlation with psychoticism.

  6. Violation of a local form of the Lieb-Oxford bound (United States)

    Vilhena, J. G.; Räsänen, E.; Lehtovaara, L.; Marques, M. A. L.


    In the framework of density-functional theory, several popular density functionals for exchange and correlation have been constructed to satisfy a local form of the Lieb-Oxford bound. In its original global expression, the bound represents a rigorous lower limit for the indirect Coulomb interaction energy. Here we employ exact-exchange calculations for the G2 test set to show that the local form of the bound is violated in an extensive range of both the dimensionless gradient and the average electron density. Hence, the results demonstrate the severity in the usage of the local form of the bound in functional development. On the other hand, our results suggest alternative ways to construct accurate density functionals for the exchange energy.

  7. A survival analysis of 1084 knees of the Oxford unicompartmental knee arthroplasty (United States)

    Bottomley, N.; Jones, L. D.; Rout, R.; Alvand, A.; Rombach, I.; Evans, T.; Jackson, W. F. M.; Beard, D. J.; Price, A. J.


    Aims The aim of this to study was to compare the previously unreported long-term survival outcome of the Oxford medial unicompartmental knee arthroplasty (UKA) performed by trainee surgeons and consultants. Patients and Methods We therefore identified a previously unreported cohort of 1084 knees in 947 patients who had a UKA inserted for anteromedial knee arthritis by consultants and surgeons in training, at a tertiary arthroplasty centre and performed survival analysis on the group with revision as the endpoint. Results The ten-year cumulative survival rate for revision or exchange of any part of the prosthetic components was 93.2% (95% confidence interval (CI) 86.1 to 100, number at risk 45). Consultant surgeons had a nine-year cumulative survival rate of 93.9% (95% CI 90.2 to 97.6, number at risk 16). Trainee surgeons had a cumulative nine-year survival rate of 93.0% (95% CI 90.3 to 95.7, number at risk 35). Although there was no differences in implant survival between consultants and trainees (p = 0.30), there was a difference in failure pattern whereby all re-operations performed for bearing dislocation (n = 7), occurred in the trainee group. This accounted for 0.6% of the entire cohort and 15% of the re-operations. Conclusion This is the largest single series of the Oxford UKA ever reported and demonstrates that good results can be achieved by a heterogeneous group of surgeons, including trainees, if performed within a high-volume centre with considerable experience with the procedure. Cite this article: Bone Joint J 2016;(10 Suppl B):22–7. PMID:27694512

  8. Photographic monitoring of soiling and decay of roadside walls in central Oxford, England (United States)

    Thornbush, Mary J.; Viles, Heather A.


    As part of the Environmental Monitoring of Integrated Transport Strategies (EMITS) project, which examined the impact of the Oxford Transport Strategy (OTS) on the soiling and decay of buildings and structures in central Oxford, England, a simple photographic survey of a sample of roadside walls was carried out in 1997, with re-surveys in 1999 and 2003. Thirty photographs were taken each time, covering an area of stonework approximately 30 × 30 cm in dimensions at 1-1.3 m above pavement level. The resulting images have been used to investigate, both qualitatively as well as quantitatively, the progression of soiling and decay. Comparison of images by eye reveals a number of minor changes in soiling and decay patterns, but generally indicates stability except at one site where dramatic, superficial damage occurred over 2 years. Quantitative analysis of decay features (concavities resulting from surface blistering, flaking, and scaling), using simple techniques in Adobe Photoshop, shows variable pixel-based size proportions of concavities across 6 years of survey. Colour images (in Lab Color) generally have a reduced proportion of pixels, representing decay features in comparison to black and white (Grayscale) images. The study conveys that colour images provide more information both for general observations of soiling and decay patterns and for segmentation of decay-produced concavities. The study indicates that simple repeat photography can reveal useful information about changing patterns of both soiling and decay, although unavoidable variation in external lighting conditions between re-surveys is a factor limiting the accuracy of change detection.

  9. new concepts of a modified hall - petch type relationship

    African Journals Online (AJOL)


    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.

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

    DEFF Research Database (Denmark)

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


    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...

  11. Analysis of Air Breathing Hall-Effect Thruster (Preprint) (United States)


    even more attractive because of multi -years sateJiite missions and high cost of payloads. In a recent paper [I), Diamant has proposed a higher orbital altitude. References ( I) Diamant K. D., "A 2-Stage Cylindrical Hall Thruster for Air Breathing Electrical Propulsion," 46’" AJAA

  12. Tondiraba jäähall = Tondiraba ice arena

    Index Scriptorium Estoniae


    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

  13. Mini array of quantum Hall devices based on epitaxial graphene

    Energy Technology Data Exchange (ETDEWEB)

    Novikov, S.; Lebedeva, N. [Department of Micro and Nanosciences, Aalto University, Micronova, Tietotie 3, Espoo (Finland); Hämäläinen, J.; Iisakka, I.; Immonen, P.; Manninen, A. J.; Satrapinski, A. [VTT Technical Research Centre of Finland Ltd., Centre for Metrology MIKES, P.O. Box 1000, 02044 VTT (Finland)


    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{sub 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{sub H,2} = 2 h/e{sup 2} was smaller than the relative standard uncertainty of the measurement (<1 × 10{sup −7}) limited by the used resistance bridge.

  14. Involving Students in Residence Halls in Hong Kong (United States)

    Ting, S. Raymond; Chan, Rebecca; Lee, Esther


    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,…

  15. Active Learning with Monty Hall in a Game Theory Class (United States)

    Brokaw, Alan J.; Merz, Thomas E.


    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…

  16. The Hall-induced stability of gravitating fluids (United States)

    Karmakar, P. K.; Goutam, H. P.


    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.

  17. Audience noise in concert halls during musical performances

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Marie, Pierre; Brunskog, Jonas


    Noise generated by the audience during musical performances is audible and sometimes disturbing. In this study, an attempt to estimate such audience noise was carried out. From the recordings of performances in five performance spaces (four concert halls and one opera house), probability density ....... (C) 2012 Acoustical Society of America. []...

  18. Clipboard: Human Y-chromosome: a hall of mirrors

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 28; Issue 5. Clipboard: Human Y-chromosome: a hall of mirrors. B J Rao Kundan Sengupta. Volume 28 Issue 5 September 2003 pp 533-534. Fulltext. Click here to view fulltext PDF. Permanent link: Author Affiliations.

  19. A conformal field theory description of fractional quantum Hall states

    NARCIS (Netherlands)

    Ardonne, E.


    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

  20. 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 ...

  1. The Marketing of Residence Halls: A Question of Positioning. (United States)

    Parker, R. Stephen; And Others


    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…

  2. Effect of Hall Current and Finite Larmor Radius Corrections on ...

    Indian Academy of Sciences (India)

    discussed the magnetothermal instability with generalized Ohms law taking the effects of electrical resistivity, Hall current, electron inertia, thermal conductivity and radiative heat-loss function. Burkert and Lin (2000) pointed out the importance of thermal instability in the formation of clumpy gas clouds and they showed that.

  3. Audience noise in concert halls during musical performances

    DEFF Research Database (Denmark)

    Marie, Pierre; Jeong, Cheol-Ho; Brunskog, Jonas


    Noise generated by the audience during musical performances is audible and sometimes disturbing. In this study, an attempt to estimate such audience noise was carried out. From the recordings of performances in five performance spaces (four concert halls and one opera house), probability density...

  4. AFM diagnostics of graphene-based quantum Hall devices

    Czech Academy of Sciences Publication Activity Database

    Sikora, A.; Woszczyna, M.; Friedemann, M.; Ahlers, F. J.; Kalbáč, Martin


    Roč. 43, 2-3 (2012), s. 479-486 ISSN 0968-4328 Institutional research plan: CEZ:AV0Z40400503 Keywords : graphene * quantum Hall effect devices * atomic force microscopy Subject RIV: CG - Electrochemistry Impact factor: 1.876, year: 2012

  5. Darrell Hall Covos-Day Books, Weltevreden Park, South Africa ...

    African Journals Online (AJOL)

    personally of the 14th and 66th Batteries and the six naval guns; Long's place was with Buller, from where he could have exercised overall control of the artillery. That way he could have dealt effectively with the ammunition problem. According to Hall, Buller apparently did not know the difference between withdrawing the ...

  6. Effect of Hall Current and Finite Larmor Radius Corrections on ...

    Indian Academy of Sciences (India)

    The finite electrical resistivity removes the effect of magnetic field and the viscosity of the medium removes the effect of FLR from the condition of radiative instability. The Hall parameter affects only the longitudinal mode of propagation and it has no effect on the transverse mode of propagation. Numerical calculation shows ...

  7. Dynamics of antiferromagnetic skyrmion driven by the spin Hall effect (United States)

    Jin, Chendong; Song, Chengkun; Wang, Jianbo; Liu, Qingfang


    Magnetic skyrmion moved by the spin-Hall effect is promising for the application of the generation racetrack memories. However, the Magnus force causes a deflected motion of skyrmion, which limits its application. Here, we create an antiferromagnetic skyrmion by injecting a spin-polarized pulse in the nanostripe and investigate the spin Hall effect-induced motion of antiferromagnetic skyrmion by micromagnetic simulations. In contrast to ferromagnetic skyrmion, we find that the antiferromagnetic skyrmion has three evident advantages: (i) the minimum driving current density of antiferromagnetic skyrmion is about two orders smaller than the ferromagnetic skyrmion; (ii) the velocity of the antiferromagnetic skyrmion is about 57 times larger than the ferromagnetic skyrmion driven by the same value of current density; (iii) antiferromagnetic skyrmion can be driven by the spin Hall effect without the influence of Magnus force. In addition, antiferromagnetic skyrmion can move around the pinning sites due to its property of topological protection. Our results present the understanding of antiferromagnetic skyrmion motion driven by the spin Hall effect and may also contribute to the development of antiferromagnetic skyrmion-based racetrack memories.

  8. Composite fermions a unified view of the quantum Hall regime

    CERN Document Server


    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.

  9. Mechanism of plateau formation in the fractional quantum Hall effect

    International Nuclear Information System (INIS)

    Bruus, H.; Hansen, O.P.; Hansen, E.B.


    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 with magnetostatic compensation layer

    DEFF Research Database (Denmark)

    Dalslet, Bjarke Thomas; Donolato, Marco; Hansen, Mikkel Fougt


    Demagnetization effects in cross-shaped planar Hall effect sensors cause inhomogeneous film magnetization and a hysteretic sensor response. Furthermore, when using sensors for detection of magnetic beads, the magnetostatic field from the sensor edges attracts and holds magnetic beads near the sen...

  11. Investigating Black Gay Male Undergraduates' Experiences in Campus Residence Halls (United States)

    Strayhorn, Terrell L.; Mullins, Taris G.


    This qualitative study sought to understand the challenges that Black gay male undergraduates confront in campus residence halls and the supports that enabled their success in facing them. Drawing on in-depth interviews with 29 participants, we found that Black gay men report varied encounters with subtle and overt forms of racism among White…

  12. Planar Hall effect sensor for magnetic micro- and nanobead detection

    DEFF Research Database (Denmark)

    Ejsing, Louise Wellendorph; Hansen, Mikkel Fougt; Menon, Aric Kumaran


    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 ...

  13. Low-frequency noise in planar Hall effect bridge sensors

    DEFF Research Database (Denmark)

    Persson, Anders; Bejhedb, R.S.; Bejhed, R.S.


    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...

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

    CSIR Research Space (South Africa)

    Blasch, E


    Full Text Available on Information Fusion (FUSION), 5-8 July 2016, Heidelberg, Germany Pragmatic data fusion uncertainty concerns: Tribute to Dave L. Hall Erik Blasch ; Paulo C. G. Costa ; J. Pieter De Villiers ; Kathryn B. Laskey ; James Llinas ; Anne-Laure Jousselme...

  15. Effect of Hall Current and Finite Larmor Radius Corrections on ...

    Indian Academy of Sciences (India)

    Abstract. The effects of finite ion Larmor radius (FLR) corrections,. Hall current and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effects of finite electrical resistivity, thermal conductivity and permeability for star formation in interstellar medium have been ...

  16. Hall kirjandus võrgustunud maailmas / Anneli Kuiv

    Index Scriptorium Estoniae

    Kuiv, Anneli


    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"

  17. Single particle detection: Phase control in submicron Hall sensors

    International Nuclear Information System (INIS)

    Di Michele, Lorenzo; Shelly, Connor; Gallop, John; Kazakova, Olga


    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.

  18. 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)


    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.

  19. 78 FR 26682 - Culturally Significant Objects Imported for Exhibition Determinations: “Hall of Ancient Egypt” (United States)


    ... Determinations: ``Hall of Ancient Egypt'' AGENCY: Department of State. ACTION: Notice, correction. SUMMARY: On... determinations made by the Department of State pertaining to the exhibition ``Hall of Ancient Egypt.'' The... additional objects to be included in the exhibition ``Hall of Ancient Egypt,'' imported from abroad for...

  20. Current Percolation in Medium with Boundaries under Quantum Hall Effect Conditions

    Directory of Open Access Journals (Sweden)

    M. U. Malakeeva


    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.

  1. The influence of profiled ceilings on sports hall acoustics : Ground effect predictions and scale model measurements

    NARCIS (Netherlands)

    Wattez, Y.C.M.; Tenpierik, M.J.; Nijs, L.


    Over the last few years, reverberation times and sound pressure levels have been measured in many sports halls. Most of these halls, for instance those made from stony materials, perform as predicted. However, sports halls constructed with profiled perforated steel roof panels have an unexpected

  2. The use of Hall technique preformed metal crowns by specialist paediatric dentists in the UK


    Roberts, A; McKay, A; Albadri, S


    Examines treatment planning involving Hall technique preformed metal crowns by specialists in paediatric dentistry. Explores clinical situations in which specialists in paediatric dentistry feel it is appropriate or not to fit Hall technique preformed metal crowns. Investigates which types of carious lesions are being treated with Hall technique preformed metal crowns by specialists in paediatric dentistry.

  3. Towards a Unified University Infrastructure: The Data Management Roll-Out at the University of Oxford

    Directory of Open Access Journals (Sweden)

    James A. J. Wilson


    Full Text Available Since presenting a paper at the International Digital Curation Conference 2010 conference entitled ‘An Institutional Approach to Developing Research Data Management Infrastructure’, the University of Oxford has come a long way in developing research data management (RDM policy, tools and training to address the various phases of the research data lifecycle. Work has now begun on integrating these various elements into a unified infrastructure for the whole university, under the aegis of the Data Management Roll-out at Oxford (Damaro Project.This paper will explain the process and motivation behind the project, and describes our vision for the future. It will also introduce the new tools and processes created by the university to tie the individual RDM components together. Chief among these is the ‘DataFinder’ – a hierarchically-structured metadata cataloguing system which will enable researchers to search for and locate research datasets hosted in a variety of different datastores from institutional repositories, through Web 2 services, to filing cabinets standing in department offices. DataFinder will be able to pull and associate research metadata from research information databases and data management plans, and is intended to be CERIF compatible. DataFinder is being designed so that it can be deployed at different levels within different contexts, with higher-level instances harvesting information from lower-level instances enabling, for example, an academic department to deploy one instance of DataFinder, which can then be harvested by another at an institutional level, which can then in turn be harvested by another at a national level.The paper will also consider the requirements of embedding tools and training within an institution and address the difficulties of ensuring the sustainability of an RDM infrastructure at a time when funding for such endeavours is limited. Our research shows that researchers (and indeed departments

  4. Spin chirality induced skew scattering and anomalous Hall effect in chiral magnets. (United States)

    Ishizuka, Hiroaki; Nagaosa, Naoto


    Noncoplanar magnetic orders in magnetic metals give rise to an anomalous Hall effect of unconventional origin, which, by the spin Berry phase effect, is known as the topological Hall effect. This effect is pronounced in the low-temperature limit, where the fluctuation of spins is suppressed. In contrast, we here discuss that the fluctuating but locally correlated spins close to the phase boundary give rise to another anomalous Hall effect, that with the opposite sign to the topological Hall effect. Using the Born approximation, we show that the anomalous Hall effect is attributed to the skew scattering induced by the local correlation of spins. The relation of the scalar spin chirality to the skew scattering amplitude is given, and the explicit formula for the Hall conductivity is derived using a semiclassical Boltzmann transport theory. Our theory potentially accounts for the sign change of the anomalous Hall effect observed in chiral magnets in the vicinity of the phase boundary.

  5. Acoustics of the Great Hall of the Moscow State Conservatory after reconstruction in 2010-2011 (United States)

    Kanev, N. G.; Livshits, A. Ya.; Möller, H.


    The Great Hall of the Moscow State Conservatory was built in the early 20th century. For more than 100 years of service, it had a high acoustic reputation both among musicians and audience. By the beginning of the 21st century, the hall was in nearly critical condition. Thus, major renovation was needed. In terms of architectural acoustics, the main task was to keep the good acoustics of the hall. This paper presents the results of acoustic parameter measurements of the hall after Reconstruction in 2010-2011. The parameters of the hall measured before and after reconstruction are also compared. The comparative acoustic characteristics between the Great Hall and world leading concert halls are given.

  6. The Manchester-Oxford Foot Questionnaire (MOXFQ): Development and validation of a summary index score. (United States)

    Morley, D; Jenkinson, C; Doll, H; Lavis, G; Sharp, R; Cooke, P; Dawson, J


    The Manchester-Oxford Foot Questionnaire (MOXFQ) is a validated 16-item, patient-reported outcome measure for evaluating outcomes of foot or ankle surgery. The original development of the instrument identified three domains. This present study examined whether the three domains could legitimately be summed to provide a single summary index score. The MOXFQ and Short-Form (SF)-36 were administered to 671 patients before surgery of the foot or ankle. Data from the three domains of the MOXFQ (pain, walking/standing and social interaction) were subjected to higher order factor analysis. Reliability and validity of the summary index score was assessed. The mean age of the participants was 52.8 years (sd 15.68; 18 to 89). Higher order principle components factor analysis produced one factor, accounting for 74.7% of the variance. The newly derived single index score was found to be internally reliable (α = 0.93) and valid, achieving at least moderate correlations (r ≥ 0.5, p < 0.001) with related (pain/function) domains of the SF-36. Analyses indicated that data from the MOXFQ can be presented in summary form. The MOXFQ summary index score (MOXFQ-Index) provides an overall indication of the outcomes of foot and ankle surgery. Furthermore, the single index reduces the number of statistical comparisons, and hence the role of chance, when exploring MOXFQ data.

  7. The influence of cultivation method on the flowering of Salvia horminum L. 'Oxford Blue'

    Directory of Open Access Journals (Sweden)

    Elżbieta Pogroszewska


    Full Text Available Salvia horminum L. 'Oxford Blue' was grown from transplants or it was direct seeded. Four sowing dates were applied: 15 March or 30 March - in a greenhouse, in order to obtain transplants, 13 April, 27 April and 11 May - sown directly into the ground. Three plant densities were applied: 25 plants×m2, 16 plants×m2, 12 plants×m2. It was found that Horminum sage can be grown from transplants or direct seeded. The cultivation from transplants is more advantageous due to the earlier flowering of plants, by about two weeks, and a better quality of inflorescences evaluated in terms of their length and size of bracteoles. Direct sowing of Horminum sage at two-week intervals from the 2nd decade of April till the 2nd decade of May ensures that by the end of August mature inflorescence stems are obtained, ready for cutting. A delay in the date of sowing results in the development of significantly shorter inflorescence stems, irrespective of the plant density. Plant density does not affect significantly the length of the period of inflorescence formation and the date of flowering, but a larger spacing is favourable to plants growing big, what results in a larger fresh weight of the above-ground portion. Sage grown from transplants responses to favourable climatic conditions by the development of bigger inflorescences.

  8. Long-term trends in the Oxford knee score following total knee replacement. (United States)

    Williams, D P; Blakey, C M; Hadfield, S G; Murray, D W; Price, A J; Field, R E


    The Oxford knee score (OKS) is a validated and widely accepted disease-specific patient-reported outcome measure, but there is limited evidence regarding any long-term trends in the score. We reviewed 5600 individual OKS questionnaires (1547 patients) from a prospectively-collected knee replacement database, to determine the trends in OKS over a ten-year period following total knee replacement. The mean OKS pre-operatively was 19.5 (95% confidence interval (CI) 18.8 to 20.2). The maximum post-operative OKS was observed at two years (mean score 34.4 (95% CI 33.7 to 35.2)), following which a gradual but significant decline was observed through to the ten-year assessment (mean score 30.1 (95% CI 29.1 to 31.1)) (p trend was observed for most of the individual OKS components (p followed by rapid deterioration (p 35 kg/m(2) (p following knee replacement.

  9. Validation of the Italian version of the Oxford Ankle Foot Questionnaire for children. (United States)

    Martinelli, Nicolò; Romeo, Giovanni; Bonifacini, Carlo; Viganò, Marco; Bianchi, Alberto; Malerba, Francesco


    The purpose of this study was to translate the Oxford Ankle Foot Questionnaire (OAFQ) into Italian, to perform a cross-cultural adaptation and to evaluate its psychometric properties. The Italian OAFQ was developed according to the recommended forward/backward translation protocol and evaluated in pediatric patients treated for symptomatic flatfoot deformity. Feasibility, reliability, internal consistency, construct validity [comparing OAFQ domains with Child Health Questionnaire (CHQ) domains] and responsiveness to surgical treatment were assessed. A total of 61 children and their parents were enrolled in the study. Results showed satisfactory levels of internal consistency for both children and parent forms. The test-retest reliability was confirmed by high ICC values for both child and parents subscales. Good construct validity was showed by patterns of relationships consistent with theoretically related domains of the CHQ. After surgery, the mean OAFQ scores improved in all the domains after treatment with the subtalar arthroereisis, for both children and parent scales (p valid instrument in order to evaluate interventions used to treat children's foot or ankle problem, but needs further study on different clinical settings.

  10. An Analysis of The Oxford Guide to Practical Lexicography (Atkins and Rundell 2008

    Directory of Open Access Journals (Sweden)

    Gilles-Maurice de Schryver


    Full Text Available

    Abstract: Since at least a decade ago, the lexicographic community at large has been demandingthat a modern textbook be designed — one that would place corpora at the centre of the lexicographicenterprise. Written by two of the most respected practising lexicographers, this book hasfinally arrived, and delivers on very many levels. This review article presents a critical analysis ofits features.


    Samenvatting: Een analyse van The Oxford Guide to Practical Lexicography(Atkins en Rundell 2008. Al minstens tien jaar lang eist de volledige lexicografischegemeenschap dat een modern tekstboek zou worden ontworpen — één dat corpora in het centrumvan de lexicografische belangstelling zou plaatsen. Geschreven door twee van de meest gerespecteerdepraktiserende lexicografen, is dit boek er nu eindelijk, en het ontgoochelt niet. Dit recensieartikelanalyseert de kenmerken ervan kritisch.


  11. Determination of baroreflex sensitivity during the modified Oxford maneuver by trigonometric regressive spectral analysis.

    Directory of Open Access Journals (Sweden)

    Julia Gasch

    Full Text Available BACKGROUND: Differences in spontaneous and drug-induced baroreflex sensitivity (BRS have been attributed to its different operating ranges. The current study attempted to compare BRS estimates during cardiovascular steady-state and pharmacologically stimulation using an innovative algorithm for dynamic determination of baroreflex gain. METHODOLOGY/PRINCIPAL FINDINGS: Forty-five volunteers underwent the modified Oxford maneuver in supine and 60° tilted position with blood pressure and heart rate being continuously recorded. Drug-induced BRS-estimates were calculated from data obtained by bolus injections of nitroprusside and phenylephrine. Spontaneous indices were derived from data obtained during rest (stationary and under pharmacological stimulation (non-stationary using the algorithm of trigonometric regressive spectral analysis (TRS. Spontaneous and drug-induced BRS values were significantly correlated and display directionally similar changes under different situations. Using the Bland-Altman method, systematic differences between spontaneous and drug-induced estimates were found and revealed that the discrepancy can be as large as the gain itself. Fixed bias was not evident with ordinary least products regression. The correlation and agreement between the estimates increased significantly when BRS was calculated by TRS in non-stationary mode during the drug injection period. TRS-BRS significantly increased during phenylephrine and decreased under nitroprusside. CONCLUSIONS/SIGNIFICANCE: The TRS analysis provides a reliable, non-invasive assessment of human BRS not only under static steady state conditions, but also during pharmacological perturbation of the cardiovascular system.

  12. Cross-cultural adaptation and validation of the Portuguese version of the Oxford Shoulder Score (OSS). (United States)

    Gonçalves, Rui Soles; Caldeira, Carolina Quintal; Rodrigues, Mónica Vieira; Felícia, Sabine Cardoso; Cavalheiro, Luís Manuel; Ferreira, Pedro Lopes


    To translate and culturally adapt the Oxford Shoulder Score (OSS) to the European Portuguese language, and to test its reliability (internal consistency, reproducibility and measurement error) and validity (construct validity). The OSS Portuguese version was obtained through translations, back-translations, consensus panels, clinical review and cognitive pre-test. Portuguese OSS, Disabilities of the Arm, Shoulder and Hand (DASH) questionnaires, and the visual analogue scales of pain at rest [VAS rest] and during movement [VAS movement] were applied to 111 subjects with shoulder pain (degenerative or inflammatory disorders) and recommended for physical therapy. A clinical and sociodemographic questionnaire was also applied. The reliability was good, with a Cronbach's alpha coefficient of 0.90, an intraclass correlation coefficient (ICC) of 0.92, a standard error of measurement (SEM) of 2.59 points and a smallest detectable change (SDC) of 7.18 points. Construct validity was supported by the confirmation of three initial hypotheses involving expected significant correlation between OSS and other measures (DASH, VAS rest and VAS movement) and between OSS and the number of days of work absenteeism. The Portuguese OSS version presented suitable psychometric properties, in terms of reliability (internal consistency, reproducibility and measurement error) and validity (construct validity).

  13. From Oxford to Hawaii ecophysiological barriers limit human progression in ten sport monuments. (United States)

    Desgorces, François-Denis; Berthelot, Geoffroy; El Helou, Nour; Thibault, Valérie; Guillaume, Marion; Tafflet, Muriel; Hermine, Olivier; Toussaint, Jean-François


    In order to understand the determinants and trends of human performance evolution, we analyzed ten outdoor events among the oldest and most popular in sports history. Best performances of the Oxford-Cambridge boat race (since 1836), the channel crossing in swimming (1875), the hour cycling record (1893), the Elfstedentocht speed skating race (1909), the cross country ski Vasaloppet (1922), the speed ski record (1930), the Streif down-hill in Kitzbühel (1947), the eastward and westward sailing transatlantic records (1960) and the triathlon Hawaii ironman (1978) all follow a similar evolutive pattern, best described through a piecewise exponential decaying model (r(2) = 0.95+/-0.07). The oldest events present highest progression curvature during their early phase. Performance asymptotic limits predicted from the model may be achieved in fourty years (2049+/-32 y). Prolonged progression may be anticipated in disciplines which further rely on technology such as sailing and cycling. Human progression in outdoor sports tends to asymptotic limits depending on physiological and environmental parameters and may temporarily benefit from further technological progresses.

  14. Backscattering spectroscopy developments for the University of Oxford Scanning External Proton Milliprobe (SEPM) (United States)

    Jarjis, R. A.


    An external beam facility has recently been developed at the University of Oxford with the aim of carrying out non-sampling material characterisations on objects which are kept at atmospheric pressure using magnetically focused scanning beam of protons. This publication deals with one part of the developments, which is the application of backscattering spectroscopy in both operational diagnosis and the analysis of solids and gases. Results are reported for tests using an experimental external beam nozzle incorporating a window for extracting the proton beam from the vacuum to a helium gas flushed external chamber housing a Si(Li) detector and a semi-conductor charged-particle detector. The latter is used in the backscattering analysis of objects whilst a second charged-particle detector is also incorporated under vacuum in order to monitor backscattering signals originating from the window and the gas present in the vicinity of the analysis volume. The aim of the development is to create controlled conditions for comprehensive analysis using both PIXE and RBS. Two new backscattering techniques are reported in this publication: (a) External Beam Multi-Dimensional Analysis (EBMA) and (b) Resonant Scattering Multi-Dimensional Analysis (RSMA). In addition, we report on the findings of an initial study of using EBMA to assess gold layer application in Japanese porcelain and Islamic manuscripts, and using RSMA in investigating gas dynamics.

  15. Prima la musica: insegnare il melodramma a Oxford negli Anni 2000

    Directory of Open Access Journals (Sweden)

    Emanuele Senici


    Full Text Available La tavola rotonda ‘L’opera monta in cattedra: didattica del melodramma’, coordinata da Lorenzo Bianconi e Annamaria Cecconi nel novembre 2007 in occasione dell’XI Colloquio di Musicologia del «Saggiatore musicale», includeva un mio breve intervento sull’esperienza didattica maturata in moduli d’argomento operistico nell’Università di Oxford, dove ho insegnato dal 1998 al 2008. L’intento era di fornire dati utili a un esercizio comparativo, il quale permettesse d’osservare le esperienze di docenti sia d’università sia di conservatorii italiani dalla prospettiva d’un sistema universitario molto diverso da ambo le istituzioni e che però, come vedremo, per le sue caratteristiche pare collocarsi a cavallo tra le due. Le pagine che seguono costituiscono un ripensamento sistematico di quelle riflessioni, nella speranza che esse possano tuttora risultare di qualche interesse a chi riflette sulla didattica del melodramma in Italia. Dopo aver delineato in breve il contesto istituzionale, presenterò un questionario proposto a due gruppi di studenti; sui risultati esporrò poi qualche riflessione conclusiva, tenendo presenti i temi proposti dal testo-base della tavola rotonda e la discussione che ebbe luogo a Bologna. Avverto infine che, benché io scriva quasi sempre al presente, ciò che dico si riferisce al periodo del mio insegnamento oxoniense: dal 2008 alcune cose possono essere cambiate.

  16. Dutch Translation of the Manchester-Oxford Foot Questionnaire: Reassessment of Reliability and Validity. (United States)

    Venkatesan, Sharmila; Schotanus, Martijn G M; Hendrickx, Roel P M

    The Manchester-Oxford Foot questionnaire (MOxFQ) is a 16-item patient reported outcome measure developed and validated for use in clinical trials involving foot surgery. The purpose of the present study was to evaluate the psychometric properties of the Dutch translation of the MOxFQ in patients who had undergone a hallux valgus correction. A total of 79 patients who had undergone hallux valgus correction completed the Medical Outcomes Study short-form 36-item questionnaire (SF-36) and MOxFQ before and after surgery. We evaluated the construct validity of the SF-36 versus the MOxFQ and the test-retest reliability. The test-retest reliability was excellent. The internal consistency of the Dutch MOxFQ was high (Cronbach's α of 0.74 to 0.86). The construct validity can be regarded as good, with moderate to high correlations between the Dutch MOxFQ and Dutch SF-36 subscales. In conclusion, the Dutch version of the MOxFQ demonstrated good reliability and validity compared with the SF-36 for use in patient groups that have undergone hallux valgus correction. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  17. Quantum Hall effect in epitaxial graphene with permanent magnets (United States)

    Parmentier, F. D.; Cazimajou, T.; Sekine, Y.; Hibino, H.; Irie, H.; Glattli, D. C.; Kumada, N.; Roulleau, P.


    We have observed the well-kown quantum Hall effect (QHE) in epitaxial graphene grown on silicon carbide (SiC) by using, for the first time, only commercial NdFeB permanent magnets at low temperature. The relatively large and homogeneous magnetic field generated by the magnets, together with the high quality of the epitaxial graphene films, enables the formation of well-developed quantum Hall states at Landau level filling factors v = ±2, commonly observed with superconducting electro-magnets. Furthermore, the chirality of the QHE edge channels can be changed by a top gate. These results demonstrate that basic QHE physics are experimentally accessible in graphene for a fraction of the price of conventional setups using superconducting magnets, which greatly increases the potential of the QHE in graphene for research and applications.

  18. Noncommutative Field Theory and the Dynamics of Quantum Hall Fluids

    CERN Document Server

    Barbón, José L F


    We study the spectrum of density fluctuations of Fractional Hall Fluids in the context of the noncommutative hidrodynamical model of Susskind. We show that, within the weak-field expansion, the leading correction to the noncommutative Chern--Simons Lagrangian (a Maxwell term in the effective action,) destroys the incompressibility of the Hall fluid due to strong UV/IR effects at one loop. We speculate on possible relations of this instability with the transition to the Wigner crystal, and conclude that calculations within the weak-field expansion must be carried out with an explicit ultraviolet cutoff at the noncommutativity scale. We point out that the noncommutative dipoles exactly match the spatial structure of the Halperin--Kallin quasiexcitons. Therefore, we propose that the noncommutative formalism must describe accurately the spectrum at very large momenta, provided no weak-field approximations are made. We further conjecture that the noncommutative open Wilson lines are `vertex operators' for the quas...

  19. Anomalous Hall-like effect probe of antiferromagnetic domain wall. (United States)

    Lang, Lili; Qiu, Xuepeng; Zhou, Shiming


    Of crucial importance to antiferromagnetic (AF) spintronic devices, AF domain wall (AFDW), created in exchange biased Y 3 Fe 5 O 12 /Ni 0.50 Co 0.50 O (NiCoO)/Pt, is characterized by anomalous Hall-like effect through magnetic proximity effect and spin Hall magnetoresistance at NiCoO/Pt interface. The AFDW thickness, in the order of nanometers, has been for the first time proved in experiments to increase with increasing temperature. AF spins within AFDW show the same chirality in decent and ascent branches of ferromagnetic magnetization reversal process. Moreover, the uncompensated magnetic moment at the NiCoO/Pt interface is of perpendicular magnetization anisotropy and changes linearly in magnitude with temperature due to the reduced coordination of the magnetic atoms on the AF surface. This work will help to clarify the mechanism of the spin current propagation in AF materials and fully understand the physics behind exchange bias.

  20. Recent advances in the spin Hall effect of light (United States)

    Ling, Xiaohui; Zhou, Xinxing; Huang, Kun; Liu, Yachao; Qiu, Cheng-Wei; Luo, Hailu; Wen, Shuangchun


    The spin Hall effect (SHE) of light, as an analogue of the SHE in electronic systems, is a promising candidate for investigating the SHE in semiconductor spintronics/valleytronics, high-energy physics and condensed matter physics, owing to their similar topological nature in the spin-orbit interaction. The SHE of light exhibits unique potential for exploring the physical properties of nanostructures, such as determining the optical thickness, and the material properties of metallic and magnetic thin films and even atomically thin two-dimensional materials. More importantly, it opens a possible pathway for controlling the spin states of photons and developing next-generation photonic spin Hall devices as a fundamental constituent of the emerging spinoptics. In this review, based on the viewpoint of the geometric phase gradient, we give a detailed presentation of the recent advances in the SHE of light and its applications in precision metrology and future spin-based photonics.

  1. On the quantization of Hall currents in presence of disorder

    CERN Document Server

    Combes, J; Hislop, P


    We review recent results of two of the authors concerning the quantization of Hall currents, in particular a general quantization formula for the difference of edge Hall conductances in semi-infinite samples with and without a confining wall. We then study the case where the Fermi energy is located in a region of localized states and discuss new regularizations. We also sketch the proof of localization for 2D-models with constant magnetic field with random potential located in a half-plane in two different situations: 1) with a zero potential in the other half plane and for energies away from the Landau levels and 2) with a confining potential in the other half plane and on an interval of energies that covers an arbitrary number of Landau levels.

  2. Interaction-induced interference in the integer quantum Hall effect (United States)

    Sivan, I.; Bhattacharyya, R.; Choi, H. K.; Heiblum, M.; Feldman, D. E.; Mahalu, D.; Umansky, V.


    In recent interference experiments with an electronic Fabry-Pérot interferometer (FPI), implemented in the integer quantum Hall effect regime, a flux periodicity of h /2 e was observed at bulk fillings νB>2.5 . The halved periodicity was accompanied by an interfering charge e*=2 e , determined by shot-noise measurements. Here, we present measurements demonstrating that, counterintuitively, the coherence and the interference periodicity of the interfering chiral edge channel are solely determined by the coherence and the enclosed flux of the adjacent edge channel. Our results elucidate the important role of the latter and suggest that a neutral chiral edge mode plays a crucial role in the pairing phenomenon. Our findings reveal that the observed pairing of electrons is not a curious isolated phenomenon, but one of many manifestations of unexpected edge physics in the quantum Hall effect regime.

  3. Effects of Enhanced Eathode Electron Emission on Hall Thruster Operation

    International Nuclear Information System (INIS)

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


    Interesting discharge phenomena are observed that have to do with the interaction between the magnetized Hall thruster plasma and the neutralizing cathode. The steadystate parameters of a highly ionized thruster discharge are strongly influenced by the electron supply from the cathode. The enhancement of the cathode electron emission above its self-sustained level affects the discharge current and leads to a dramatic reduction of the plasma divergence and a suppression of large amplitude, low frequency discharge current oscillations usually related to an ionization instability. These effects correlate strongly with the reduction of the voltage drop in the region with the fringing magnetic field between the thruster channel and the cathode. The measured changes of the plasma properties suggest that the electron emission affects the electron cross-field transport in the thruster discharge. These trends are generalized for Hall thrusters of various configurations.

  4. Exact law for homogeneous compressible Hall magnetohydrodynamics turbulence (United States)

    Andrés, N.; Galtier, S.; Sahraoui, F.


    We derive an exact law for three-dimensional (3D) homogeneous compressible isothermal Hall magnetohydrodynamic turbulence, without the assumption of isotropy. The Hall current is shown to introduce new flux and source terms that act at the small scales (comparable or smaller than the ion skin depth) to significantly impact the turbulence dynamics. The law provides an accurate means to estimate the energy cascade rate over a broad range of scales covering the magnetohydrodynamic inertial range and the sub-ion dispersive range in 3D numerical simulations and in in situ spacecraft observations of compressible turbulence. This work is particularly relevant to astrophysical flows in which small-scale density fluctuations cannot be ignored such as the solar wind, planetary magnetospheres, and the interstellar medium.

  5. Simulating Smoke Filling in Big Halls by Computational Fluid Dynamics

    Directory of Open Access Journals (Sweden)

    W. K. Chow


    Full Text Available Many tall halls of big space volume were built and, to be built in many construction projects in the Far East, particularly Mainland China, Hong Kong, and Taiwan. Smoke is identified to be the key hazard to handle. Consequently, smoke exhaust systems are specified in the fire code in those areas. An update on applying Computational Fluid Dynamics (CFD in smoke exhaust design will be presented in this paper. Key points to note in CFD simulations on smoke filling due to a fire in a big hall will be discussed. Mathematical aspects concerning of discretization of partial differential equations and algorithms for solving the velocity-pressure linked equations are briefly outlined. Results predicted by CFD with different free boundary conditions are compared with those on room fire tests. Standards on grid size, relaxation factors, convergence criteria, and false diffusion should be set up for numerical experiments with CFD.

  6. Tearing mode dynamics and sawtooth oscillation in Hall-MHD (United States)

    Ma, Zhiwei; Zhang, Wei; Wang, Sheng


    Tearing mode instability is one of the most important dynamic processes in space and laboratory plasmas. Hall effects, resulted from the decoupling of electron and ion motions, could cause the fast development and perturbation structure rotation of the tearing mode and become non-negligible. We independently developed high accuracy nonlinear MHD code (CLT) to study Hall effects on the dynamic evolution of tearing modes with Tokamak geometries. It is found that the rotation frequency of the mode in the electron diamagnetic direction is in a good agreement with analytical prediction. The linear growth rate increases with increase of the ion inertial length, which is contradictory to analytical solution in the slab geometry. We further find that the self-consistently generated rotation largely alters the dynamic behavior of the double tearing mode and the sawtooth oscillation. National Magnetic Confinement Fusion Science Program of China under Grant No. 2013GB104004 and 2013GB111004.

  7. Error modelling of quantum Hall array resistance standards (United States)

    Marzano, Martina; Oe, Takehiko; Ortolano, Massimo; Callegaro, Luca; Kaneko, Nobu-Hisa


    Quantum Hall array resistance standards (QHARSs) are integrated circuits composed of interconnected quantum Hall effect elements that allow the realization of virtually arbitrary resistance values. In recent years, techniques were presented to efficiently design QHARS networks. An open problem is that of the evaluation of the accuracy of a QHARS, which is affected by contact and wire resistances. In this work, we present a general and systematic procedure for the error modelling of QHARSs, which is based on modern circuit analysis techniques and Monte Carlo evaluation of the uncertainty. As a practical example, this method of analysis is applied to the characterization of a 1 MΩ QHARS developed by the National Metrology Institute of Japan. Software tools are provided to apply the procedure to other arrays.

  8. Fractional Quantum Hall States in a Ge Quantum Well. (United States)

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


    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.

  9. 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)


    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.

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

    DEFF Research Database (Denmark)

    Gade, Anders Christian


    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...... of experiments in a 1:20 scale model indicated that among several suggested means the following would be the most effective and acceptable: (a) changing the shape of the sidewalls in the platform area in order to make them reflect sound back to the musicians more effectively; (b) lowering and redesigning...

  11. Performance of metal Hall sensors based on copper

    Czech Academy of Sciences Publication Activity Database

    Sentkerestiová, J.; Ďuran, Ivan; Kovařík, Karel; Viererbl, L.; Kohout, Michal


    Roč. 88, 6-8 (2013), s. 1310-1314 ISSN 0920-3796. [Symposium on Fusion Technology (SOFT-27)/27./. Liège, 24.09.2012-28.09.2012] R&D Projects: GA MŠk 7G10072; GA MŠk(CZ) LM2011021 Grant - others:EUROATOM(XE) FU07-CT-2007-00060 Institutional support: RVO:61389021 ; RVO:68378271 Keywords : Metal Hall sensor * Magnetic diagnostics * Copper Hall sensor * Fusion reactors * Neutron irradiation Subject RIV: BL - Plasma and Gas Discharge Physics; BM - Solid Matter Physics ; Magnetism (FZU-D) Impact factor: 1.149, year: 2013

  12. Matrix effective theories of the fractional quantum Hall effect

    International Nuclear Information System (INIS)

    Cappelli, Andrea; Rodriguez, Ivan D


    The present understanding of nonperturbative ground states in the fractional quantum Hall effect is based on effective theories of the Jain 'composite fermion' excitations. We review the approach based on matrix variables, i.e. D0 branes, originally introduced by Susskind and Polychronakos. We show that the Maxwell-Chern-Simons matrix gauge theory provides a matrix generalization of the quantum Hall effect, where the composite-fermion construction naturally follows from gauge invariance. The matrix ground states obtained by suitable projections of higher Landau levels are found to be in one-to-one correspondence with the Laughlin and Jain hierarchical states. The matrix theory possesses a physical limit for commuting matrices that could be reachable while staying in the same phase.

  13. Sensitivity of resistive and Hall measurements to local inhomogeneities

    DEFF Research Database (Denmark)

    Koon, Daniel W.; Wang, Fei; Petersen, Dirch Hjorth


    We derive exact, analytic expressions for the sensitivity of sheet resistance and Hall sheet resistance measurements to local inhomogeneities for the cases of nonzero magnetic fields, strong perturbations, and perturbations over a finite area, extending our earlier results on weak perturbations. ...... simulations on both a linear four-point probe array on a large circular disc and a van der Pauw square geometry. Furthermore, the results also agree well with Náhlík et al. published experimental results for physical holes in a circular copper foil disc.......We derive exact, analytic expressions for the sensitivity of sheet resistance and Hall sheet resistance measurements to local inhomogeneities for the cases of nonzero magnetic fields, strong perturbations, and perturbations over a finite area, extending our earlier results on weak perturbations. We...

  14. Fast micro Hall effect measurements on small pads

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Petersen, Dirch Hjorth; Nielsen, Peter F.


    Sheet resistance, carrier mobility, and sheet carrier density are important parameters in semiconductor production, and it is therefore important to be able to rapidly and accurately measure these parameters even on small samples or pads. The interpretation of four-point probe measurements on small...... pads is non-trivial. In this paper we discuss how conformal mapping can be used to evaluate theoretically expected measurement values on small pads. Theoretical values calculated from analytical mappings of simple geometries are compared to the values found from the numerical conformal mapping...... of a square onto the infinite half-plane, where well-established solutions are known. Hall effect measurements are performed to show, experimentally, that it is possible to measure Hall mobility in less than one minute on squares as small as 7070 lm2 with a deviation of 66.5% on a 1r level from accurate...

  15. Anomalous Hall effect and Nernst effect in itinerant ferromagnets

    International Nuclear Information System (INIS)

    Miyasato, T.; Abe, N.; Fujii, T.; Asamitsu, A.; Onose, Y.; Onoda, S.; Nagaosa, N.; Tokura, Y.


    Anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) in many ferromagnetic metals including pure metals, oxides, and chalcogenides, are studied to obtain unified understandings of their origins. We show the universal behavior of anomalous Hall conductivity σ xy as a function of longitudinal conductivity σ xx over six orders of magnitude, which is well reproduced by a recent theory assuming both the intrinsic and extrinsic contributions to the AHE. ANE is closely related with AHE and gives us further information about the electronic state in the ground state of ferromagnets. The temperature dependence of transverse Peltier coefficient α xy shows almost similar behavior among various ferromagnets, and this behavior is expected from a conventional Boltzmann transport theory

  16. Anomalous Hall effect and Nernst effect in itinerant ferromagnets

    International Nuclear Information System (INIS)

    Asamitsu, A.; Miyasato, T.; Abe, N.; Fujii, T.; Onose, Y.; Onoda, S.; Nagaosa, N.; Tokura, Y.


    Anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) in many ferromagnetic metals including pure metals, oxides, and calcogenides, are studied to obtain unified understandings of their origins. We show the universal behavior of anomalous Hall conductivity σ xy as a function of longitudinal conductivity σ xx over six orders of magnitude, which is well reproduced by rigorous unified theory assuming both intrinsic and extrinsic contributions to the AHE. ANE is closely related with AHE and gives us further information about the electronic state in the ground state of ferromagnets. The temperature dependence of transverse Peltier coefficient α xy shows almost similar behavior among various ferromagnets and this behavior is expected from a conventional Boltzmann transport theory

  17. Anomalous Hall effect scaling in ferromagnetic thin films

    KAUST Repository

    Grigoryan, Vahram L.


    We propose a scaling law for anomalous Hall effect in ferromagnetic thin films. Our approach distinguishes multiple scattering sources, namely, bulk impurity, phonon for Hall resistivity, and most importantly the rough surface contribution to longitudinal resistivity. In stark contrast to earlier laws that rely on temperature- and thickness-dependent fitting coefficients, this scaling law fits the recent experimental data excellently with constant parameters that are independent of temperature and film thickness, strongly indicating that this law captures the underlying physical processes. Based on a few data points, this scaling law can even fit all experimental data in full temperature and thickness range. We apply this law to interpret the experimental data for Fe, Co, and Ni and conclude that (i) the phonon-induced skew scattering is unimportant as expected; (ii) contribution from the impurity-induced skew scattering is negative; (iii) the intrinsic (extrinsic) mechanism dominates in Fe (Co), and both the extrinsic and intrinsic contributions are important in Ni.

  18. Theory of anomalous Hall effect in europium chalcogenides

    International Nuclear Information System (INIS)

    Sinkkonen, J.


    Considering the exchange interaction between the conduction electrons in a broad 5d-type band and the magnetic electrons in the localized 4f-shells, it is shown that in addition to the ordinary d-f exchange diagonal in band index, there is also a non-diagonal interaction representing a one particle transfer between the conduction and magnetic electrons. Including the spin-orbit coupling, an effective Hamiltonian for the conductionelectrons is obtained, which contains additional asymmetric scattering terms. The ordinary d-f exchange is treated as the dominating scattering interaction. The anomatous Hall effect results by skew scattering and side jump mechanisms. The density matrix method is used to derive the transport properties. The effect of the correlation of spins at different lattice sites is discussed. The model indicates that the anomatous Hall effect can be seen in heavily doped samples. (author)

  19. Quantum Hall effect in epitaxial graphene with permanent magnets. (United States)

    Parmentier, F D; Cazimajou, T; Sekine, Y; Hibino, H; Irie, H; Glattli, D C; Kumada, N; Roulleau, P


    We have observed the well-kown quantum Hall effect (QHE) in epitaxial graphene grown on silicon carbide (SiC) by using, for the first time, only commercial NdFeB permanent magnets at low temperature. The relatively large and homogeneous magnetic field generated by the magnets, together with the high quality of the epitaxial graphene films, enables the formation of well-developed quantum Hall states at Landau level filling factors v = ±2, commonly observed with superconducting electro-magnets. Furthermore, the chirality of the QHE edge channels can be changed by a top gate. These results demonstrate that basic QHE physics are experimentally accessible in graphene for a fraction of the price of conventional setups using superconducting magnets, which greatly increases the potential of the QHE in graphene for research and applications.

  20. Edge states in quantum Hall effect in graphene

    International Nuclear Information System (INIS)

    Gusynin, V.P.; Miransky, V.A.; Sharapov, S.G.; Shovkovy, I.A.


    We review recent results concerning the spectrum of edge states in the quantum Hall effect in graphene. In particular, special attention is paid to the derivation of the conditions under which gapless edge states exist in the spectrum of graphene with 'zigzag' and 'armchair' edges. It is found that in the case of a half-plane or a ribbon with zigzag edges, there are gapless edge states only when a spin gap dominates over a Dirac mass gap. In the case of a half-plane with an armchair edge, the existence of the gapless edge states depends on the specific type of Dirac mass gaps. The implications of these results for the dynamics in the quantum Hall effect in graphene are discussed

  1. Spin Hall effect-driven spin torque in magnetic textures

    KAUST Repository

    Manchon, Aurelien


    Current-induced spin torque and magnetization dynamics in the presence of spin Hall effect in magnetic textures is studied theoretically. The local deviation of the charge current gives rise to a current-induced spin torque of the form (1 - ΒM) × [(u 0 + αH u 0 M) ∇] M, where u0 is the direction of the injected current, H is the Hall angle and is the non-adiabaticity parameter due to spin relaxation. Since αH and ×can have a comparable order of magnitude, we show that this torque can significantly modify the current-induced dynamics of both transverse and vortex walls. © 2011 American Institute of Physics.

  2. On the low-field Hall coefficient of graphite

    Directory of Open Access Journals (Sweden)

    P. Esquinazi


    Full Text Available We have measured the temperature and magnetic field dependence of the Hall coefficient (RH in three, several micrometer long multigraphene samples of thickness between ∼9 to ∼30 nm in the temperature range 0.1 to 200 K and up to 0.2 T field. The temperature dependence of the longitudinal resistance of two of the samples indicates the contribution from embedded interfaces running parallel to the graphene layers. At low enough temperatures and fields RH is positive in all samples, showing a crossover to negative values at high enough fields and/or temperatures in samples with interfaces contribution. The overall results are compatible with the reported superconducting behavior of embedded interfaces in the graphite structure and indicate that the negative low magnetic field Hall coefficient is not intrinsic of the ideal graphite structure.

  3. Effect of quantum tunneling on spin Hall magnetoresistance. (United States)

    Ok, Seulgi; Chen, Wei; Sigrist, Manfred; Manske, Dirk


    We present a formalism that simultaneously incorporates the effect of quantum tunneling and spin diffusion on the spin Hall magnetoresistance observed in normal metal/ferromagnetic insulator bilayers (such as Pt/Y 3 Fe 5 O 12 ) and normal metal/ferromagnetic metal bilayers (such as Pt/Co), in which the angle of magnetization influences the magnetoresistance of the normal metal. In the normal metal side the spin diffusion is known to affect the landscape of the spin accumulation caused by spin Hall effect and subsequently the magnetoresistance, while on the ferromagnet side the quantum tunneling effect is detrimental to the interface spin current which also affects the spin accumulation. The influence of generic material properties such as spin diffusion length, layer thickness, interface coupling, and insulating gap can be quantified in a unified manner, and experiments that reveal the quantum feature of the magnetoresistance are suggested.

  4. Extraordinary Hall-effect in colloidal magnetic nanoparticle films

    Energy Technology Data Exchange (ETDEWEB)

    Ben Gur, Leah; Tirosh, Einat [School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Segal, Amir [School of Physics, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Markovich, Gil, E-mail: [School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Gerber, Alexander, E-mail: [School of Physics, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel)


    Colloidal nickel nanoparticles (NPs) coated with polyvinylpyrrolidone (PVP) were synthesized. The nanoparticle dispersions were deposited on substrates and dried under mild heating to form conductive films. The films exhibited very small coercivity, nearly metallic conductivity, and a significant extraordinary Hall effect signal. This method could be useful for preparing simple, printed magnetic field sensors with the advantage of relatively high sensitivity around zero magnetic field, in contrast to magnetoresistive sensors, which have maximal field sensitivity away from zero magnetic field. - Highlights: • Ni nanoparticle ink capable of forming conductive films on drying. • The Ni nanoparticle films exhibit significant extraordinary Hall effect. • This system could be used for preparing printed magnetic field sensors integrated in 3D printed structures.

  5. Admittance measurements in the quantum Hall effect regime

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, C., E-mail: [Departamento de Física, Universidad Militar Nueva Granada, Carrera 11 # 101-80, Bogotá D.C. (Colombia); Laboratorio de Magnetismo, Departamento de Física, Universidad de los Andes, A.A. 4976, Bogotá D.C. (Colombia); Consejo, C.; Chaubet, C. [Laboratoire Charles Coulomb L2C, Université Montpellier II, Pl. E. Bataillon, 34095 Montpellier Cedex 5 (France)


    In this work we present an admittance study of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime. We have studied several Hall bars in different contacts configurations in the frequency range 100 Hz–1 MHz. Our interpretation is based on the Landauer–Büttiker theory and takes into account both the capacitance and the topology of the coaxial cables which are connected to the sample holder. We show that we always observe losses through the capacitive impedance of the coaxial cables, except in the two contacts 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 2DEG and show its dependence with the filling factor ν.

  6. Valley Hall effect and Nernst effect in strain engineered graphene (United States)

    Niu, Zhi Ping; Yao, Jian-ming


    We theoretically predict the existence of tunneling valley Hall effect and Nernst effect in the normal/strain/normal graphene junctions, where a strained graphene is sandwiched by two normal graphene electrodes. By applying an electric bias a pure transverse valley Hall current with longitudinal charge current is generated. If the system is driven by a temperature bias, a valley Nernst effect is observed, where a pure transverse valley current without charge current propagates. Furthermore, the transverse valley current can be modulated by the Fermi energy and crystallographic orientation. When the magnetic field is further considered, we obtain a fully valley-polarized current. It is expected these features may be helpful in the design of the controllable valleytronic devices.

  7. Forced Hall magnetic reconnection: Parametric variation of the 'Newton Challenge'

    International Nuclear Information System (INIS)

    Huba, J.D.


    A parametric study of forced magnetic reconnection using a 2D Hall magnetohydrodynamic (MHD) code based on the 'Newton Challenge' is presented. The 'Newton Challenge' defined a magnetic reconnection problem in which reconnection was initiated by a spatially and temporally dependent inflow velocity on the upstream boundary. In this study the magnitude and time dependence of the inflow velocity are varied, as well as the length of the system and the boundary conditions. The general conclusion is that reconnection occurs sooner and faster for stronger impulsive drives (e.g., larger inflow velocities and longer time scales). The results are fairly insensitive to system length. Finally, the Hall MHD results are compared to results from a particle-in-cell simulation study

  8. Hall effect in quantum critical charge-cluster glass (United States)

    Wu, Jie; Bollinger, Anthony T.; Sun, Yujie


    Upon doping, cuprates undergo a quantum phase transition from an insulator to a d-wave superconductor. The nature of this transition and of the insulating state is vividly debated. Here, we study the Hall effect in La2-xSrxCuO4 (LSCO) samples doped near the quantum critical point at x ˜ 0.06. Dramatic fluctuations in the Hall resistance appear below TCG ˜ 1.5 K and increase as the sample is cooled down further, signaling quantum critical behavior. We explore the doping dependence of this effect in detail, by studying a combinatorial LSCO library in which the Sr content is varied in extremely fine steps, Δx ˜ 0.00008. We observe that quantum charge fluctuations wash out when superconductivity emerges but can be restored when the latter is suppressed by applying a magnetic field, showing that the two instabilities compete for the ground state.

  9. Data handling for the wide-angle hall jet experiment

    International Nuclear Information System (INIS)

    Cassel, D.; Engelmann, R.; Gordon, H.; Grannis, P.; Mallik, U.; Meadows, B.; Morris, T.; Plano, R.; Saulys, A.; Stein, S.


    The data handling needs for a jet production experiment in the wide-angle hall are discussed. The several layers of triggering and a data acquisition system were designed, the configuration of the local intersection computer system was discussed, and the time required to analyze a typical event was estimated. It was concluded that the experiment does not appear to place unrealistic demands on detector technology. The slow trigger was believed to be the crucial aspect of the experiment. 15 figures, 1 tables

  10. Tunneling between edge states in a quantum spin Hall system. (United States)

    Ström, Anders; Johannesson, Henrik


    We analyze a quantum spin Hall device with a point contact connecting two of its edges. The contact supports a net spin tunneling current that can be probed experimentally via a two-terminal resistance measurement. We find that the low-bias tunneling current and the differential conductance exhibit scaling with voltage and temperature that depend nonlinearly on the strength of the electron-electron interaction.

  11. Design and Operation of Hall Thruster with Segmented Electrodes

    International Nuclear Information System (INIS)

    Litvak, A.A.; Dorf, L.A.; Fisch, N.J.; Raitses, Y.


    Principles of the Hall thruster with segmented electrodes are explored. A suitable vacuum facility was put into service. For purposes of comparison between segmented and conventional thruster approaches, a modular laboratory prototype thruster was designed and built. Under conventional operation, the thruster achieves state-of-the-art efficiencies (56% at 300 V and 890 W). Very preliminary results under operation with segmented electrodes are also described

  12. Preliminary Study of Arcjet Neutralization of Hall Thruster Clusters (Postprint) (United States)


    report on fundamental experiments to understand how much electron current can be drawn to a surrogate anode from the plume of low power arcjets ...operating on hydrogen and helium, and then demonstrate the first successful operation of a low power Hall thruster- arcjet neutralizer package. In the...concept demonstration. The arcjet operated at very low powers (~ 70-120W) on helium, at a mass flow rate of 4.5 mg/s, and was able to effectively

  13. Inverse Spin Hall Effect in SNS Josephson Junctions


    Mal'shukov, A. G.; Sadjina, Severin; Brataas, Arne


    We consider DC supercurrents in SNS junctions. Spin-orbit coupling in combination with Zeeman fields can induce an effective vector potential in the normal conductor. As a consequence, an out-of-plane spin-density varying along the transverse direction causes a longitudinal phase difference between the superconducting terminals. The resulting equilibrium phase coherent supercurrent is analogue to the non-equilibrium inverse spin Hall effect in normal conductors. We explicitly compute the effe...

  14. Investigations of Probe Induced Perturbations in a Hall Thruster

    International Nuclear Information System (INIS)

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


    An electrostatic probe used to measure spatial plasma parameters in a Hall thruster generates perturbations of the plasma. These perturbations are examined by varying the probe material, penetration distance, residence time, and the nominal thruster conditions. The study leads us to recommendations for probe design and thruster operating conditions to reduce discharge perturbations, including metal shielding of the probe insulator and operation of the thruster at lower densities

  15. Options for Energy Upgrade of the Hall B Tagger

    International Nuclear Information System (INIS)

    H. Crannell; D. Sober


    Four options for an energy upgrade of the present Hall-B Tagger have been considered. These are: (1) Boost the magnetic field in the present Tagger; (2) Replace the Tagger with a new Tagger system; (3) Install a pre-Tagger magnetic chacain, and (4) Use the present Tagger as part of the beam dump. In this document each of these options is described briefly, the advantages and disadvantages of each are presented, and a very rough cost of implementation is suggested

  16. Pseudospectral Model for Hybrid PIC Hall-effect Thruster Simulation (United States)


    an axial-azimuthal hybrid-PIC HET code is under development, initially with a reduced set of physics. In particular, dynamic ionization is ignored...Approved for public release; distribution unlimited. 412 TW/PAO Clearance No. 15306 xenon only) is with PIC and the electron description is as a...Bilyeu, D., and Tran, J., “ Dynamic Particle Weight Remapping in Hybrid PIC Hall-effect Thruster Simulation,” 34th Int. Electric Propulsion Conf

  17. Resistive mode in rotating plasma columns including the hall current

    International Nuclear Information System (INIS)

    Galvao, R.M.O.


    A new resistive mode is shown to exist in rotating plasma columns. The mode is localized in the neighbourhood of the radius where the angular velocity of the bulk plasma is equal to minus half the local angular velocity of the ions. This singular point is caused by the Hall term in the generalized Ohm law. The growth rate of the mode scales with eta sup(1/2), where eta is the plasma resistivity. (Author) [pt

  18. Hall Effect Influence on a Highly Conducting Fluid

    Energy Technology Data Exchange (ETDEWEB)

    Witalis, E.A.


    The properties of an incompressible perfect fluid exhibiting Hall effect is investigated in the limit of infinite electrical conductivity and mobility. The magnetic field strength and the fluid velocity are found to obey the equations B = {mu}{rho}/{sigma} x curlV and V -{mu}/({sigma}{mu}{sub 0}) x curlB (MKS units) where {rho}, {sigma} and {mu} denote mass density, conductivity and charge carrier mobility. Some physical interpretations and applications are given.

  19. Effet Hall quantique, liquides de Luttinger et charges fractionnaires (United States)

    Roche, Patrice; Rodriguez, V.; Glattli, D. Christian

    We review some basic properties of the Fractional Quantum Hall Effect and particularly address the physics of the edge states. The chiral Luttinger liquid properties of the edges are discussed and probed experimentally using transport measurements. Shot noise measurements, which allow determination of the quasiparticle charge are also discussed. To cite this article: P. Roche et al., C. R. Physique 3 (2002) 717-732.

  20. Two-dimensional Ising physics in quantum Hall ferromagnets

    Czech Academy of Sciences Publication Activity Database

    Jungwirth, Tomáš; MacDonald, A. H.; Rezayi, E. H.


    Roč. 12, - (2002), s. 1-7 ISSN 1386-9477 R&D Projects: GA ČR GA202/01/0754; GA MŠk OC 514.10 Institutional research plan: CEZ:AV0Z1010914 Keywords : quantum Hall ferromagnets * higher Landau levels * domain walls Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.107, year: 2002

  1. Focused ion beam patterned Hall nano-sensors

    International Nuclear Information System (INIS)

    Candini, A.; Gazzadi, G.C.; Di Bona, A.; Affronte, M.; Ercolani, D.; Biasiol, G.; Sorba, L.


    By means of focused ion beam milling, we fabricate Hall magnetometers with active areas as small as 100x100nm 2 . The constituent material can either be metallic (Au), semimetallic (Bi) or doped bulk semiconducting (Si doped GaAs). We experimentally show that Au nano-probes can work from room temperature down to liquid helium with magnetic flux sensitivity -1 Φ 0

  2. Measurement of Safety Factor Using Hall Probes on CASTOR Tokamak

    Czech Academy of Sciences Publication Activity Database

    Kovařík, Karel; Ďuran, Ivan; Bolshakova, I.; Holyaka, R.; Erashok, V.


    Roč. 56, suppl.B (2006), s. 104-110 ISSN 0011-4626. [Symposium on Plasma Physics and Technology/22nd./. Praha, 26.6.2006-29.6.2006] R&D Projects: GA AV ČR(CZ) KJB100430504 Institutional research plan: CEZ:AV0Z20430508 Keywords : Plasma * tokamak * safety factor * hall probe Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.568, year: 2006

  3. Parametric studies of the Hall Thruster at Soreq

    International Nuclear Information System (INIS)

    Ashkenazy, J.; Rattses, Y.; Appelbaum, G.


    An electric propulsion program was initiated at Soreq a few years ago, aiming at the research and development of advanced Hall thrusters for various space applications. The Hall thruster accelerates a plasma jet by an axial electric field and an applied radial magnetic field in an annular ceramic channel. A relatively large current density (> 0.1 A/cm 2 ) can be obtained, since the acceleration mechanism is not limited by space charge effects. Such a device can be used as a small rocket engine onboard spacecraft with the advantage of a large jet velocity compared with conventional rocket engines (10,000-30,000 m/s vs. 2,000-4,800 m/s). An experimental Hall thruster was constructed at Soreq and operated under a broad range of operating conditions and under various configurational variations. Electrical, magnetic and plasma diagnostics, as well as accurate thrust and gas flow rate measurements, have been used to investigate the dependence of thruster behavior on the applied voltage, gas flow rate, magnetic field, channel geometry and wall material. Representative results highlighting the major findings of the studies conducted so far are presented

  4. Quantum Entanglement and the Topological Order of Fractional Hall States (United States)

    Rezayi, Edward


    Fractional quantum Hall states or, more generally, topological phases of matter defy Landau classification based on order parameter and broken symmetry. Instead they have been characterized by their topological order. Quantum information concepts, such as quantum entanglement, appear to provide the most efficient method of detecting topological order solely from the knowledge of the ground state wave function. This talk will focus on real-space bi-partitioning of quantum Hall states and will present both exact diagonalization and quantum Monte Carlo studies of topological entanglement entropy in various geometries. Results on the torus for non-contractible cuts are quite rich and, through the use of minimum entropy states, yield the modular S-matrix and hence uniquely determine the topological order, as shown in recent literature. Concrete examples of minimum entropy states from known quantum Hall wave functions and their corresponding quantum numbers, used in exact diagonalizations, will be given. In collaboration with Clare Abreu and Raul Herrera. Supported by DOE Grant DE-SC0002140.

  5. Precision Electron Beam Polarimetry in Hall C at Jefferson Lab (United States)

    Gaskell, David


    The electron beam polarization in experimental Hall C at Jefferson Lab is measured using two devices. The Hall-C/Basel Møller polarimeter measures the beam polarization via electron-electron scattering and utilizes a novel target system in which a pure iron foil is driven to magnetic saturation (out of plane) using a superconducting solenoid. A Compton polarimeter measures the polarization via electron-photon scattering, where the photons are provided by a high-power, CW laser coupled to a low gain Fabry-Perot cavity. In this case, both the Compton-scattered electrons and backscattered photons provide measurements of the beam polarization. Results from both polarimeters, acquired during the Q-Weak experiment in Hall C, will be presented. In particular, the results of a test in which the Møller and Compton polarimeters made interleaving measurements at identical beam currents will be shown. In addition, plans for operation of both devices after completion of the Jefferson Lab 12 GeV Upgrade will also be discussed.

  6. Mission and System Advantages of Iodine Hall Thrusters (United States)

    Dankanich, John W.; Szabo, James; Pote, Bruce; Oleson, Steve; Kamhawi, Hani


    The exploration of alternative propellants for Hall thrusters continues to be of interest to the community. Investments have been made and continue for the maturation of iodine based Hall thrusters. Iodine testing has shown comparable performance to xenon. However, iodine has a higher storage density and resulting higher ?V capability for volume constrained systems. Iodine's vapor pressure is low enough to permit low-pressure storage, but high enough to minimize potential adverse spacecraft-thruster interactions. The low vapor pressure also means that iodine does not condense inside the thruster at ordinary operating temperatures. Iodine is safe, it stores at sub-atmospheric pressure, and can be stored unregulated for years on end; whether on the ground or on orbit. Iodine fills a niche for both low power (10kW) electric propulsion regimes. A range of missions have been evaluated for direct comparison of Iodine and Xenon options. The results show advantages of iodine Hall systems for both small and microsatellite application and for very large exploration class missions.

  7. Paired quantum Hall states on noncommutative two-tori

    Energy Technology Data Exchange (ETDEWEB)

    Marotta, Vincenzo [Dipartimento di Scienze Fisiche, Universita di Napoli ' Federico II' and INFN, Sezione di Napoli, Compl. universitario M. Sant' Angelo, Via Cinthia, 80126 Napoli (Italy); Naddeo, Adele, E-mail: naddeo@sa.infn.i [CNISM, Unita di Ricerca di Salerno and Dipartimento di Fisica ' E. R. Caianiello' , Universita degli Studi di Salerno, Via Salvador Allende, 84081 Baronissi (Italy)


    By exploiting the notion of Morita equivalence for field theories on noncommutative tori and choosing rational values of the noncommutativity parameter theta (in appropriate units), a one-to-one correspondence between an Abelian noncommutative field theory (NCFT) and a non-Abelian theory of twisted fields on ordinary space can be established. Starting from this general result, we focus on the conformal field theory (CFT) describing a quantum Hall fluid (QHF) at paired states fillings nu=m/(pm+2) Cristofano et al. (2000) , recently obtained by means of m-reduction procedure, and show that it is the Morita equivalent of a NCFT. In this way we extend the construction proposed in Marotta and Naddeo (2008) for the Jain series nu=m/(2pm+1) . The case m=2 is explicitly discussed and the role of noncommutativity in the physics of quantum Hall bilayers is emphasized. Our results represent a step forward the construction of a new effective low energy description of certain condensed matter phenomena and help to clarify the relationship between noncommutativity and quantum Hall fluids.

  8. An edge index for the quantum spin-Hall effect

    International Nuclear Information System (INIS)

    Prodan, Emil


    Quantum spin-Hall systems are topological insulators displaying dissipationless spin currents flowing at the edges of the samples. In contradistinction to the quantum Hall systems where the charge conductance of the edge modes is quantized, the spin conductance is not and it remained an open problem to find the observable whose edge current is quantized. In this paper, we define a particular observable and the edge current corresponding to this observable. We show that this current is quantized and that the quantization is given by the index of a certain Fredholm operator. This provides a new topological invariant that is shown to take the generic values 0 and 2, in line with the Z 2 topological classification of time-reversal invariant systems. The result gives an effective tool for the investigation of the edge structure in quantum spin-Hall systems. Based on a reasonable assumption, we also show that the edge conducting channels are not destroyed by a random edge. (fast track communication)

  9. Giant anisotropic magnetoresistance in a quantum anomalous Hall insulator (United States)

    Kandala, Abhinav; Richardella, Anthony; Kempinger, Susan; Liu, Chao-Xing; Samarth, Nitin


    When a three-dimensional ferromagnetic topological insulator thin film is magnetized out-of-plane, conduction ideally occurs through dissipationless, one-dimensional (1D) chiral states that are characterized by a quantized, zero-field Hall conductance. The recent realization of this phenomenon, the quantum anomalous Hall effect, provides a conceptually new platform for studies of 1D transport, distinct from the traditionally studied quantum Hall effects that arise from Landau level formation. An important question arises in this context: how do these 1D edge states evolve as the magnetization is changed from out-of-plane to in-plane? We examine this question by studying the field-tilt-driven crossover from predominantly edge-state transport to diffusive transport in Crx(Bi,Sb)2−xTe3 thin films. This crossover manifests itself in a giant, electrically tunable anisotropic magnetoresistance that we explain by employing a Landauer–Büttiker formalism. Our methodology provides a powerful means of quantifying dissipative effects in temperature and chemical potential regimes far from perfect quantization. PMID:26151318

  10. Hall Effect in Bulk-Doped Organic Single Crystals. (United States)

    Ohashi, Chika; Izawa, Seiichiro; Shinmura, Yusuke; Kikuchi, Mitsuru; Watase, Seiji; Izaki, Masanobu; Naito, Hiroyoshi; Hiramoto, Masahiro


    The standard technique to separately and simultaneously determine the carrier concentration per unit volume (N, cm -3 ) and the mobility (μ) of doped inorganic single crystals is to measure the Hall effect. However, this technique has not been reported for bulk-doped organic single crystals. Here, the Hall effect in bulk-doped single-crystal organic semiconductors is measured. A key feature of this work is the ultraslow co-deposition technique, which reaches as low as 10 -9 nm s -1 and enables us to dope homoepitaxial organic single crystals with acceptors at extremely low concentrations of 1 ppm. Both the hole concentration per unit volume (N, cm -3 ) and the Hall mobility (μ H ) of bulk-doped rubrene single crystals, which have a band-like nature, are systematically observed. It is found that these rubrene single crystals have (i) a high ionization rate and (ii) scattering effects because of lattice disturbances, which are peculiar to this organic single crystal. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Stability of the Hall sensors performance under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Duran, I.; Hron, M.; Stockel, J. [Institute of Plasma Physics, Association EURATOM/IPP.CR, Praha (Czech Republic); Viererbl, L.; Vsolak, R.; Cerva, V. [Nuclear Research Institute plc (Czech Republic); Bolshakova, I.; Holyaka, R. [Lviv Polytechnic National Univ. (Ukraine); Vayakis, G. [ITER International Team, Naka Joint Work Site, Naka, Ibaraki (Japan)


    A principally new diagnostic method must be developed for magnetic measurements in steady state regime of operation of fusion reactor. One of the options is the use of transducers based on Hall effect. The use of Hall sensors in ITER is presently limited by their questionable radiation and thermal stability. Issues of reliable operation in ITER like radiation and thermal environment are addressed in the paper. The results of irradiation tests of candidate Hall sensors in LVR-15 and IBR-2 experimental fission reactors are presented. Stable operation (deterioration of sensitivity below one percent) of the specially prepared sensors was demonstrated during irradiation by the total fluence of 3.10{sup 16} n/cm{sup 2} in IBR-2 reactor. Increasing the total neutron fluence up to 3.10{sup 17} n/cm{sup 2} resulted in deterioration of the best sensor's output still below 10% as demonstrated during irradiation in LVR-15 fission reactor. This level of neutron is already higher than the expected ITER life time neutron fluence for a sensor location just outside the ITER vessel. (authors)

  12. Dynamical quantum Hall effect in the parameter space. (United States)

    Gritsev, V; Polkovnikov, A


    Geometric phases in quantum mechanics play an extraordinary role in broadening our understanding of fundamental significance of geometry in nature. One of the best known examples is the Berry phase [M.V. Berry (1984), Proc. Royal. Soc. London A, 392:45], which naturally emerges in quantum adiabatic evolution. So far the applicability and measurements of the Berry phase were mostly limited to systems of weakly interacting quasi-particles, where interference experiments are feasible. Here we show how one can go beyond this limitation and observe the Berry curvature, and hence the Berry phase, in generic systems as a nonadiabatic response of physical observables to the rate of change of an external parameter. These results can be interpreted as a dynamical quantum Hall effect in a parameter space. The conventional quantum Hall effect is a particular example of the general relation if one views the electric field as a rate of change of the vector potential. We illustrate our findings by analyzing the response of interacting spin chains to a rotating magnetic field. We observe the quantization of this response, which we term the rotational quantum Hall effect.

  13. Typology of Retractable Roof Structures in Stadiums and Sports Halls

    Directory of Open Access Journals (Sweden)

    Andrej Mahovič


    Full Text Available Retractable roof structures are one of the four fundamental systems (in addition to the playing area, stands and facade in a stadium and sports hall. The roof protects users against various weather conditions and creates optimum circumstances for carrying out different activities. Stadiums and sports halls with retractable roof structures can host a greater variety of activities, improve the quality of their implementation and the quality of visitors’ experience, and affect the perception and experience of people using or observing such buildings. A retractable roof structure allows for natural lighting and ventilation of the venue, gives optimal conditions for grass growth on the playing field, and reduces costs of use and maintenance of the building. Different typologies of movement of roof structures (frequency of opening and closing, design of the structure, and methods of movement are categorised in terms of their architectural and structural design. Application of different retractable roof systems worldwide is indicator of their effectiveness and efficiency, and is basis for use of movement also in other fundamental systems of stadiums and sports halls. Research and identification of characteristics of retractable roof structures lead to the design of new moving systems that can with the application of the moving principle change the purpose of movable elements or assume the characteristics of other fundamental systems.


    Bekker, Marthinus J; Cumming, Tania D; Osborne, Nikola K.P; Bruining, Angela M; McClean, Julia I; Leland, Louis S


    This experiment investigated the combined use of visual prompts, daily feedback, and rewards to reduce electricity consumption in a university residential hall. After a 17-day baseline period, the experimental intervention was introduced in the intervention hall, and no change was made in the control hall. Energy usage decreased in the intervention hall, but energy usage did not change appreciably in the control hall. In the intervention hall, mean daytime and nighttime savings were 16.2% and 10.7%, respectively, compared to savings of 3.8% (day) and 6.5% (night) in the control hall. PMID:21119909

  15. 2D-resistivity surveys of deteriorating historic stonework in Oxford, UK (United States)

    Sass, O.; Viles, H. A.


    Historic stonework deteriorates in often very complex ways and despite many years of research on the topic, we are still a long way from being able to predict its occurrence and severity. As most deterioration processes involve water, techniques which provide a better picture of the moisture contents and fluctuations within stonework are very valuable in attempts to improve understanding. 2D resistivity methods can provide useful information about moisture distributions within porous historic stonework. We report on a series of experiments on historic walls within the centre of Oxford, UK, which illustrate varying degrees of deterioration including catastrophic decay. Using medical electrodes we have been able to carry out non-invasive and non-destructive 2D resistivity surveys to study the distribution and amount of water stored in deteriorating limestone walls. Fifteen vertical profiles, each 2-2.5 m in length, have been monitored at five sites. Furthermore, simulated driving rain experiments have been carried out at two sites. The data indicate the diversity and complexity of moisture distributions within these walls. Replacement stone patches show consistently higher moisture conditions than the surrounding stone. Some profiles show wetter sections towards the base of the wall, usually where a plinth is absent. Conversely, hard stone plinths obviously reduce capillary rise from ground water. However, at several sites we noticed a wetter zone immediately above the top of the plinth which often correlates with the occurrence of catastrophic decay - indicating that the plinth may encourage concentration of decay. Most profiles indicate the presence of wetter patches 5-10cm behind the wall face under blackened crusts. Such patches of heightened absolute moisture contents could play a very important role in encouraging catastrophic decay. Severely decayed sections of profiles often exhibit wetter near-surface conditions than surrounding stonework, whilst areas with

  16. Assessing the performance of the Oxford Nanopore Technologies MinION

    Directory of Open Access Journals (Sweden)

    T. Laver


    Full Text Available The Oxford Nanopore Technologies (ONT MinION is a new sequencing technology that potentially offers read lengths of tens of kilobases (kb limited only by the length of DNA molecules presented to it. The device has a low capital cost, is by far the most portable DNA sequencer available, and can produce data in real-time. It has numerous prospective applications including improving genome sequence assemblies and resolution of repeat-rich regions. Before such a technology is widely adopted, it is important to assess its performance and limitations in respect of throughput and accuracy. In this study we assessed the performance of the MinION by re-sequencing three bacterial genomes, with very different nucleotide compositions ranging from 28.6% to 70.7%; the high G + C strain was underrepresented in the sequencing reads. We estimate the error rate of the MinION (after base calling to be 38.2%. Mean and median read lengths were 2 kb and 1 kb respectively, while the longest single read was 98 kb. The whole length of a 5 kb rRNA operon was covered by a single read. As the first nanopore-based single molecule sequencer available to researchers, the MinION is an exciting prospect; however, the current error rate limits its ability to compete with existing sequencing technologies, though we do show that MinION sequence reads can enhance contiguity of de novo assembly when used in conjunction with Illumina MiSeq data.

  17. The Oxford Ankle Foot Questionnaire for children: responsiveness and longitudinal validity. (United States)

    Morris, Christopher; Doll, Helen; Davies, Neville; Wainwright, Andrew; Theologis, Tim; Willett, Keith; Fitzpatrick, Ray


    To evaluate how scores from the Oxford Ankle Foot Questionnaire change over time and with treatment using both distribution-based and anchor-based approaches. Eighty children aged 5-16 and their parent or career completed questionnaires at orthopaedic or trauma outpatient clinics. They were asked to complete and return a second set of questionnaires again within 2 weeks (retest), and then mailed a third set of questionnaires to complete again after 2 months (follow-up). The follow-up questionnaires included a global rating of change 'transition' item. Child- and parent-reported mean domain scores (Physical, School & Play, and Emotional) were all stable at retest, whereas positive mean changes were observed at follow-up. As we hypothesised, trauma patients had poorer scores than elective patients at baseline, and showed greater improvement at follow-up. For trauma patients, mean changes in per cent scores were large (scores improved between 40 and 56 for the Physical and School & Play domains, and 17 and 21 for Emotional); all effect sizes (ES) were large (>0.8). For elective patients, the mean improvement in per cent scores were more moderate (Physical: child 10, ES = 0.4, parent 11, ES = 0.5; School & Play child 0, ES = 0, parent 9 ES = 0.4; Emotional: child 6, ES = 0.2; parents 8, ES > 0.3). Minimal detectable change (MDC(90)), an indication of measurement error, ranged from 6 to 8. Half the standard deviation of baseline scores ranged from 11 to 18. Minimal important difference could only be calculated for elective patients (9 child and 13 parent ratings), these ranged from 7 to 17. The findings support the responsiveness and longitudinal validity of the scales. Changes in domain scores of, or exceeding, the MDC(90) (6-8) are likely to be beyond measurement error; further work is required to refine the estimate of change that can be considered important.

  18. Cross-cultural adaptation and validation of the Korean version of the Oxford shoulder score. (United States)

    Roh, Young Hak; Noh, Jung Ho; Kim, Woo; Oh, Joo Han; Gong, Hyun Sik; Baek, Goo Hyun


    The Oxford shoulder score (OSS) is being used increasingly and has been adapted cross-culturally in some Western countries. On the other hand, there are few validated translations of the OSS in Asian countries. This study translated and adapted cross-culturally the original OSS to produce a Korean version, and assessed the validity and reliability of the Korean version of the OSS (Korean OSS). One hundred and five patients with shoulder pain caused by degenerative or inflammatory disorders completed the Korean OSS and Korean disability of arm, shoulder and hand (DASH). In addition, the pain score by a visual analog scale (VAS) during activity and at rest, subjective assessment of activities of daily living (ADL), the active range of motion (ROM), and measurements of the abduction strength (strength) were included in the validation process. There were no major linguistic or cultural problems during the forward and backward translations of the MHQ, except for a minor change due to cultural discrepancies in eating such as using a spoon and chopsticks by one dominant hand instead of a knife and fork by two hands. The internal consistency was high (Cronbach's alpha 0.91). The reproducibility test showed no significant difference (Intra-class coefficient 0.95). The construct validity, which was tested by the Pearson correlation coefficient revealed a strong correlation (r > 0.6) between the Korean OSS against subscale of DASH disability/symptom, DASH work and ADL, as well as a moderate correlation (0.3 music, strength, ROM, pain during activity and pain at rest. The Korean OSS proved to be valid by demonstrating a significant correlation with the patient-based upper extremity questionnaire and clinical assessment. The application and evaluation of the instrument is feasible and understandable among patients in Korea.

  19. Study on mechanics of bodies under the action of sound pollution in industrial halls. Part II: Analysis of sound pressure inside the hall (United States)

    Arghir, M.; Lăpuşan, I. L.


    In this work, it is taking into account all these phenomena of sounds propagation in given space. Within the framework of the given research is a study in industrial park "Teraplast" from Bistriţa-Năsăud county. This is industrial products for pvc constructions. From the submissions made to the workshops of processing industrial park "Teraplast" has been found, that noise is produced mainly in the power pumps hall. The registrations were made during a normal working days. The recorders made, for one minute, with recorder (NL32, Japanese society RION) in the pump's hall 12 positions were introduced in a high- capacity computer. This second part of the paper contains a natural continuation of the study conducted in the first part. Through the composition of sound waves for each pump in part according to the construction of the hall, gives the sound field generated by sources of power pumps during simultaneous operation. Field of noise sources inside the hall of power pumps determines an acoustic pressure on the walls of the hall. Taking into consideration the frequencies that are threatening the construction of the hall, will be presented successively acoustic pressure what special expertise to the hall walls the pressures of 230Hz, 350Hz, 800Hz and 1400Hz. This study is important for the acoustic pressure made from the "Teraplast" enterprise inside, and outside the halls.

  20. Strong anisotropic anomalous Hall effect and spin Hall effect in the chiral antiferromagnetic compounds Mn3X (X =Ge , Sn, Ga, Ir, Rh, and Pt) (United States)

    Zhang, Yang; Sun, Yan; Yang, Hao; Železný, Jakub; Parkin, Stuart P. P.; Felser, Claudia; Yan, Binghai


    We have carried out a comprehensive study of the intrinsic anomalous Hall effect and spin Hall effect of several chiral antiferromagnetic compounds Mn3X (X = Ge, Sn, Ga, Ir, Rh and Pt) by ab initio band structure and Berry phase calculations. These studies reveal large and anisotropic values of both the intrinsic anomalous Hall effect and spin Hall effect. The Mn3X materials exhibit a noncollinear antiferromagnetic order which, to avoid geometrical frustration, forms planes of Mn moments that are arranged in a Kagome-type lattice. With respect to these Kagome planes, we find that both the anomalous Hall conductivity (AHC) and the spin Hall conductivity (SHC) are quite anisotropic for any of these materials. Based on our calculations, we propose how to maximize AHC and SHC for different materials. The band structures and corresponding electron filling, that we show are essential to determine the AHC and SHC, are compared for these different compounds. We point out that Mn3Ga shows a large SHC of about 600 (ℏ /e ) (Ωcm) -1 . Our work provides insights into the realization of strong anomalous Hall effects and spin Hall effects in chiral antiferromagnetic materials.

  1. Integrated Stirling Convertor and Hall Thruster Test Conducted (United States)

    Mason, Lee S.


    An important aspect of implementing Stirling Radioisotope Generators on future NASA missions is the integration of the generator and controller with potential spacecraft loads. Some recent studies have indicated that the combination of Stirling Radioisotope Generators and electric propulsion devices offer significant trip time and payload fraction benefits for deep space missions. A test was devised to begin to understand the interactions between Stirling generators and electric thrusters. An electrically heated RG- 350 (350-W output) Stirling convertor, designed and built by Stirling Technology Company of Kennewick, Washington, under a NASA Small Business Innovation Research agreement, was coupled to a 300-W SPT-50 Hall-effect thruster built for NASA by the Moscow Aviation Institute (RIAME). The RG-350 and the SPT-50 shown, were installed in adjacent vacuum chamber ports at NASA Glenn Research Center's Electric Propulsion Laboratory, Vacuum Facility 8. The Stirling electrical controller interfaced directly with the Hall thruster power-processing unit, both of which were located outside of the vacuum chamber. The power-processing unit accepted the 48 Vdc output from the Stirling controller and distributed the power to all the loads of the SPT-50, including the magnets, keeper, heater, and discharge. On February 28, 2001, the Glenn test team successfully operated the Hall-effect thruster with the Stirling convertor. This is the world's first known test of a dynamic power source with electric propulsion. The RG-350 successfully managed the transition from the purely resistive load bank within the Stirling controller to the highly capacitive power-processing unit load. At the time of the demonstration, the Stirling convertor was operating at a hot temperature of 530 C and a cold temperature of -6 C. The linear alternator was producing approximately 250 W at 109 Vac, while the power-processing unit was drawing 175 W at 48 Vdc. The majority of power was delivered to the

  2. Experiments on Quantum Hall Topological Phases in Ultra Low Temperatures

    International Nuclear Information System (INIS)

    Du, Rui-Rui


    This project is to cool electrons in semiconductors to extremely low temperatures and to study new states of matter formed by low-dimensional electrons (or holes). At such low temperatures (and with an intense magnetic field), electronic behavior differs completely from ordinary ones observed at room temperatures or regular low temperature. Studies of electrons at such low temperatures would open the door for fundamental discoveries in condensed matter physics. Present studies have been focused on topological phases in the fractional quantum Hall effect in GaAs/AlGaAs semiconductor heterostructures, and the newly discovered (by this group) quantum spin Hall effect in InAs/GaSb materials. This project consists of the following components: 1) Development of efficient sample cooling techniques and electron thermometry: Our goal is to reach 1 mK electron temperature and reasonable determination of electron temperature; 2) Experiments at ultra-low temperatures: Our goal is to understand the energy scale of competing quantum phases, by measuring the temperature-dependence of transport features. Focus will be placed on such issues as the energy gap of the 5/2 state, and those of 12/5 (and possible 13/5); resistive signature of instability near 1/2 at ultra-low temperatures; 3) Measurement of the 5/2 gaps in the limit of small or large Zeeman energies: Our goal is to gain physics insight of 5/2 state at limiting experimental parameters, especially those properties concerning the spin polarization; 4) Experiments on tuning the electron-electron interaction in a screened quantum Hall system: Our goal is to gain understanding of the formation of paired fractional quantum Hall state as the interaction pseudo-potential is being modified by a nearby screening electron layer; 5) Experiments on the quantized helical edge states under a strong magnetic field and ultralow temperatures: our goal is to investigate both the bulk and edge states in a quantum spin Hall insulator under

  3. Rasch analysis of the Dutch version of the Oxford elbow score

    Directory of Open Access Journals (Sweden)

    de Haan J


    Full Text Available Jeroen de Haan1, Niels Schep2, Wim Tuinebreijer2, Peter Patka2, Dennis den Hartog21Department of Surgery and Traumatology, Westfriesgasthuis, Hoorn, the Netherlands; 2Department of Surgery and Traumatology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the NetherlandsBackground: The Oxford elbow score (OES is a patient-rated, 12-item questionnaire that measures quality of life in relation to elbow disorders. This English questionnaire has been proven to be a reliable and valid instrument. Recently, the OES has been translated into Dutch and examined for its reliability, validity, and responsiveness in a group of Dutch patients with elbow pathology. The aim of this study was to analyze the Dutch version of the OES (OES-DV in combination with Rasch analysis or the one-parameter item response theory to examine the structure of the questionnaire.Methods: The OES-DV was administered to 103 patients (68 female, 35 male. The mean age of the patients was 44.3 ± 14.7 (range 15–75 years. Rasch analysis was performed using the Winsteps® Rasch Measurement Version and a rating scale parameterization.Results: The person separation index, which is a measure of person reliability, was excellent (2.30. All the items of the OES had a reasonable mean square infit or outfit value between 0.6 and 1.7. The threshold of items were ordered, so the categories can function as intended. Principal component analysis of the residuals partly confirmed the multidimensionality of the English version of the OES. The OES distinguished 3.4 strata, which indicates that about three ranges can be differentiated.Conclusion: Rasch analysis of the OES-DV showed that the data fit to the stringent Rasch model. The multidimensionality of the English version of the OES was partly confirmed, and the four items of the function and three items of the pain domain were recognized as separate domains. The category rating scale of the OES-DV works well. The OES can

  4. The reliability, validity and responsiveness of the Dutch version of the Oxford elbow score

    Directory of Open Access Journals (Sweden)

    Patka Peter


    Full Text Available Abstract Background The Oxford elbow score (OES is an English questionnaire that measures the patients' subjective experience of elbow surgery. The OES comprises three domains: elbow function, pain, and social-psychological effects. This questionnaire can be completed by the patient and used as an outcome measure after elbow surgery. The aim of this study was to develop and evaluate the Dutch version of the translated OES for reliability, validity and responsiveness with respect to patients after elbow trauma and surgery. Methods The 12 items of the English-language OES were translated into Dutch and then back-translated; the back-translated questionnaire was then compared to the original English version. The OES Dutch version was completed by 69 patients (group A, 60 of whom had an elbow luxation, four an elbow fracture and five an epicondylitis. QuickDASH, the visual analogue pain scale (VAS and the Mayo Elbow Performance Index (MEPI were also completed to examine the convergent validity of the OES in group A. To calculate the test-retest reliability and responsiveness of the OES, this questionnaire was completed three times by 43 different patients (group B. An average of 52 days elapsed between therapy and the administration of the third OES (SD = 24.1. Results The Cronbach's α coefficients for the function, pain and social-psychological domains were 0.90, 0.87 and 0.90, respectively. The intra-class correlation coefficients for the domains were 0.87 for function, 0.89 for pain and 0.87 for social-psychological. The standardised response means for the domains were 0.69, 0.46 and 0.60, respectively, and the minimal detectable changes were 27.6, 21.7 and 24.0, respectively. The convergent validity for the function, pain and social-psychological domains, which were measured as the Spearman's correlation of the OES domains with the MEPI, were 0.68, 0.77 and 0.77, respectively. The Spearman's correlations of the OES domains with QuickDASH were

  5. A Modern Introduction to Quantum Field Theory (Oxford Master Series in Physics)

    Energy Technology Data Exchange (ETDEWEB)

    Straumann, N [Universitaet Zuerich (Switzerland)


    This new book on quantum field theory by Michele Maggiore fits well into the Oxford Master Series in Physics, which is designed for final year undergraduate and beginning graduate students in physics. It is based on the teaching experience of the author with students in the fourth year at the University of Geneva. In this sense it is a two-semester course book for students exposed to quantum field theory for the first time. Maggiore gives, on slightly less than 300 pages, a balanced introduction to a vast field of twentieth century physics that will help students going on to study more advanced and specialized courses. Beside applications to many processes in particle physics that can also be found in many other textbooks, the author emphasizes conceptual, structural and methodological aspects of quantum field theory. After an introductory chapter, the group theoretical tools required to implement Lorentz invariance in quantum field theory are developed on 30 pages. Chapter 3 is devoted to classical field theory, emphasizing symmetries and conservation laws. The quantization of free fields in the next chapter follows traditional lines. Here one may miss a section describing the mathematical structure of the Fock space. It is also not said that in infinite dimensions von Neumann's uniqueness theorem for the representations of the canonical commutation relations no longer holds. The operations C, P, T are carefully discussed. In the relatively long chapter 5, perturbation theory and renormalization are developed. In this context the author discusses the modern view on renormalizability, and also emphasizes in a separate section the seriousness of the cosmological constant problem in quantum field theory. The next three chapters provide applications of the theory, especially to quantum electrodynamics and the low-energy limit of the electroweak theory. Chapters 9, 10, and 11 are meant as a bridge to more advanced courses. In these, path integral quantization, non

  6. Translation and validation of the Dutch version of the Oxford 12-item knee questionnaire for knee arthroplasty

    NARCIS (Netherlands)

    Haverkamp, Daniël; Breugem, Stefan J. M.; Sierevelt, Inger N.; Blankevoort, Leendert; van Dijk, C. Nick


    Background In 1998, the Oxford 12-item knee questionnaire was developed by Dawson et al. as a self-administered disease- and site-specific questionnaire, specifically developed for knee arthroplasty patients. Since then, it has proven to be an effective outcome questionnaire, and is widely used.

  7. 77 FR 65856 - Foreign-Trade Subzone 93G-Oxford, NC; Notification of Proposed Production Activity Revlon... (United States)


    ... Activity Revlon Consumer Products Corporation (Cosmetics and Personal Care Products) Revlon Consumer... activity for its facility in Oxford, North Carolina. The notification conforming to the requirements of the...., Washington, DC 20230-0002, and in the ``Reading Room'' section of the Board's Web site, which is accessible...

  8. 77 FR 59639 - Bear Lake National Wildlife Refuge, Bear Lake County, ID and Oxford Slough Waterfowl Production... (United States)


    ... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service [FWS-R1-R-2012-N095; 1265-0000-10137-S3] Bear Lake National Wildlife Refuge, Bear Lake County, ID and Oxford Slough Waterfowl Production Area... comprehensive conservation plan and environmental assessment (Draft CCP/EA) for the Bear Lake National Wildlife...

  9. 19th Biennial International Nineteenth-Century Music Conference, Faculty of Music, University of Oxford, 11.-13. 7. 2016

    Czech Academy of Sciences Publication Activity Database

    Myslivcová, Eva


    Roč. 53, 2-3 (2016), s. 300-301 ISSN 0018-7003. [19th Biennial International Nineteenth-Century Music Conference. Oxford, 11.07.2016-13.07.2016] Institutional support: RVO:68378076 Keywords : music ological conference * nineteenth-century music * Antonin Dvorak * opera Subject RIV: AL - Art, Architecture, Cultural Heritage

  10. Spin disorder effect in anomalous Hall effect in MnGa (United States)

    Mendonça, A. P. A.; Varalda, J.; Schreiner, W. H.; Mosca, D. H.


    We report on resistivity and Hall effect in MnGa thin films grown by molecular beam epitaxy on GaAs substrates. Highly (1 1 1)-textured MnGa film with L10 structure exhibits hard magnetic properties with coercivities as high as 20 kOe and spin disorder mechanisms contributing to the Hall conductivity at room temperature. Density functional theory calculations were performed to determine the intrinsic Berry curvature in the momentum space with chiral spin structure that results in an anomalous Hall conductivity of 127 (Ωcm)-1 comparable to that measured at low temperature. In addition to residual and side-jump contributions, which are enhanced by thermal activation, both anomalous Hall conductivity and Hall angle increase between 100 K and room temperature. The present results reinforce the potential of Mn-Ga system for developing Hall effect-based spintronic devices.

  11. Theoretical calculation of the Hall mobility of InNxAs1− x alloys ...

    Indian Academy of Sciences (India)


    Nov 27, 2015 ... The Hall mobilities of InAs and InN0.01As0.99 are presented in the temperature range of 30–600 K. It is shown that incorporation of even small amount of nitrogen leads to an abrupt reduction of the Hall mobility in InNAs1− at low temperatures. The effect of alloy random scattering on the Hall mobility of ...

  12. Optimal Volume for Concert Halls Based on Ando’s Subjective Preference and Barron Revised Theories

    Directory of Open Access Journals (Sweden)

    Salvador Cerdá


    Full Text Available The Ando-Beranek’s model, a linear version of Ando’s subjective preference theory, obtained by the authors in a recent work, was combined with Barron revised theory. An optimal volume region for each reverberation time was obtained for classical music in symphony orchestra concert halls. The obtained relation was tested with good agreement with the top rated halls reported by Beranek and other halls with reported anomalies.

  13. Magnetoresistivity and Hall resistivity of a YBCO thin film in a tilted magnetic field

    International Nuclear Information System (INIS)

    Amirfeiz, M.; Cimberle, M. R.; Ferdeghini, C.; Giannini, E.; Grassano, G.; Marre', D.; Putti, M.; Siri, A. S.


    In this paper they present magnetoresistivity and Hall effect measurements performed on a YBCO epitaxial film as a function of the angle θ between the external magnetic field and the a-b planes. The resistivity and Hall effect measurements are analyzed in term of the general scaling approach proposed by Blatter and coworkers; the Hall conductivity data are examined to separate the contributions due to vortices and quasi particles

  14. Wendelstein 7-X Torus Hall Layout and System Integration

    International Nuclear Information System (INIS)

    Hartmann, D.; Damiani, C.; Hartfuss, H.-J.; Krampitz, R.; Neuner, U.


    Wendelstein 7-X is an experimental fusion device presently under construction in Greifswald, Germany, to study the stellarator concept at reactor relevant parameters und steady-state conditions. The heart of the machine consists of the torus that houses the superconducting coils and the plasma vacuum vessel. It is located nearly in the center of a 30 m x 30 m x 20 m hall. A large number of components need to be placed in close proximity of the torus to provide the system with the required means, e.g. cryogenic gases, cooling water, electricity, and to integrate it with the peripheral diagnostic and heating components. The arrangement of these components has to be supported by suitable structures, and has to be optimized to allow for installation, maintenance, and repair. In addition, space has to be provided for escape routes and for sufficient distance between components that could negatively influence each other's performance, etc. The layout of the components has been done over many years using 3D CAD software. It was based on simple geometric models of the components and of the additionally required space. Presently the layout design is being detailed and updated by replacing the original coarse models with more refined estimates or - in some cases - with as-built models. All interface requirements are carefully taken into account. Detailed routing was specified for the cryo and cooling water supply lines whose design and installation is outsourced. Due to the limited space available and severely restricted access during experimental campaigns, the requirement to put auxiliary components like electronic racks into the torus hall is being queried. The paper summarizes the present state of the component layout in the torus hall, and how the peripheral supply, diagnostics, and heating systems are integrated into the machine. (author)

  15. Low-Cost High-Performance Hall Thruster Support System, Phase II (United States)

    National Aeronautics and Space Administration — Colorado Power Electronics (CPE) has built an innovative modular power processing unit (PPU) for Hall Thrusters, including discharge, magnet, heater and keeper...

  16. Detection and Solution of Indoor Air Quality Problems in a Danish Town Hall

    DEFF Research Database (Denmark)

    Hyldgård, Carl-Erik; Brohus, Henrik

    In connection with the research programme "Healthy Buildings", a building with indoor air quality problems was selected for further investigations. A Danish town hall was chosen because of many complaints over several years. A full-scale mock-up of a typical town hall office was built in the clim......In connection with the research programme "Healthy Buildings", a building with indoor air quality problems was selected for further investigations. A Danish town hall was chosen because of many complaints over several years. A full-scale mock-up of a typical town hall office was built...

  17. Quantum Hall effect and hopping conductivity in n-InGaAs/InAlAs nanoheterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Gudina, S. V., E-mail:; Arapov, Yu. G.; Saveliev, A. P.; Neverov, V. N.; Podgornykh, S. M.; Shelushinina, N. G.; Yakunin, M. V. [Russian Academy of Sciences, Mikheev Institute of Metal Physics, Ural Branch (Russian Federation); Vasil’evskii, I. S.; Vinichenko, A. N. [National Research Nuclear University MEPhI (Russian Federation)


    The longitudinal and Hall magnetoresistances are measured in the quantum Hall effect regime in the n-InGaAs/InAlAs heterostructures at temperatures of T = (1.8–30) K in magnetic fields up to B = 9 T. Temperature-induced transport in the region of the longitudinal resistance minima, corresponding to the plateau regions at Hall resistance, is investigated within the framework of the concept of hopping conductivity in a strongly localized electron system. The analysis of variable-range hopping conductivity in the region of the second, third, and fourth plateau of the quantum Hall effect provides the possibility of determining the localization length exponent.

  18. Recent multi-purpose hall designs in Denmark with physically variable acoustics

    DEFF Research Database (Denmark)

    Gade, Anders Christian


    house. This hall is used for symphonic concerts and musicals as well as drama and conferences. In this hall, maintaining or even increasing G along with a reduction in T is advantageous, especially in the drama theatre mode. The paper will describe the design of these two halls along with acoustic...... and be used for chamber music concerts, symphony orchestra rehearsals, and amplified speech. For the latter two functions, a reduction in G along with reduction in T was considered favorable. The hall with variable volume is the recently opened Esbjerg Musikhus seating 1100 and equipped with a full stage...

  19. Long Life Miniature Hall Thruster Enabling Low Cost Human Precursor Missions (United States)

    National Aeronautics and Space Administration — Key and Central Objectives: This investigation aims to demonstrate that the application of magnetic shielding technology on miniature Hall thrusters will...

  20. Cantonese version of the Oxford Cognitive Screen (OCS: Validation for stroke survivors in Hong Kong

    Directory of Open Access Journals (Sweden)

    Pinky Hiu Ping Lam


    Full Text Available Background Stroke-induced cognitive impairments are critical predictors of poor functional outcomes. They adversely affect recovery and reduce independent performance of basic activities of daily living (ADL and instrumental ADL (Zinn et al., 2004. Choices of cognitive assessment tools specific to the Cantonese speaking stroke population in Hong Kong are limited. The Cantonese version of the Western Aphasia Battery (Cantonese-WAB was specifically developed for examining language impairments. The Cantonese version of MMSE (Cantonese-MMSE and Hong Kong Montreal Cognitive Assessment (HK-MoCA, designed to detect cognitive deficits associated with dementia, lacked important measures of writing, neglect, and praxis where impairments were commonly found in stroke. More critically, most tasks in these two screeners required relatively intact auditory comprehension and verbal responses from participants. Presence of aphasia can, therefore, lead to underestimation of cognitive abilities. Aims Extending Chan et al.’s (2013 development of a Cantonese version of the Birmingham Cognitive Screen (BCoS to be used in Hong Kong, our first aim was to validate the Oxford Cognitive Screen (OCS, built on similar principles to the BCoS test but is shorter (15 minutes and can be used in acute settings, for Cantonese-speaking stroke survivors. This tool, including assessment of aphasia, apraxia, attention, memory, and spatial neglect, was designed to be neglect- and aphasia-friendly by using multi-modal presentation, forced-choice testing procedures, and vertical layouts. The second aim was to determine which cognitive domain(s in HK-OCS would best predict functional outcomes. Procedures Seventy normal individuals were recruited to establish the normative data of HK-OCS. Norm was developed for three age groups (59 years. Direct percentile conversions for each sub-test scores were used and cut-off scores were set at the top 5th percentile. Forty six native Cantonese

  1. Hall Plateaus at magic angles in ultraquantum Bismuth (United States)

    Benoît, Fauqué.


    The behaviour of a three-dimensional electron gas in the presence of a magnetic field strong enough to put all carriers in the first Landau level (i.e. beyond the quantum limit) is a longstanding question of theoretical condensed matter physics [1]. This issue has been recently explored by two high-field experiments on elemental semi-metal Bismuth. In a first study of transport coefficients (which are dominated by hole-like carriers), the Nernst coefficient presented three unexpected maxima that are concomitant with quasi-plateaux in the Hall coefficient [2]. In a second series of experiments, torque magnetometry (which mainly probes the three Dirac valley electron pockets) detected a field-induced phase transition [3]. The full understanding of the electron and hole behaviours above the quantum limit of pure Bi is therefore still under debate. In this talk, we will present our measurement of the Hall resistivity and torque magnetometry with magnetic field up to 31 T and rotating in the trigonal-bisectrix plane [4]. The Hall response is dominated by the hole pockets according to its sign as well as the period and the angular dependence of its quantum oscillations. In the vicinity of the quantum limit, it presents additional anomalies which are the fingerprints of the electron pockets. We found that for particular orientations of the magnetic field (namely ``magic angles''), the Hall response becomes field-independent within the experimental resolution around 20T. This drastic dependence of the plateaux on the field orientation provides strong constraints for theoretical scenarios. [4pt] [1] Bertrand I. Halperin, Japanese Journal of Applied Physics, 26, Supplement 26-3 (1987).[0pt] [2] Kamran Behnia, Luis Balicas, Yakov Kopelevich, Science, 317, 1729 (2008).[0pt] [3] Lu Li, J. G. Checkelsky, Y. S. Hor, C. Uher, A. F. Hebard, R. J. Cava, and N. P. Ong , Science, 321, 5888 (2008).[0pt] [4] Benoît Fauqu'e, Luis Balicas, Ilya Sheikin, Jean Paul Issi and Kamran Behnia

  2. Photoproduction of Light and Exotic Mesons in Hall D (United States)

    Meyer, Curtis


    The Jefferson Lab Hall D collaboration is proposing a program to search for and study gluonic excitations of mesons using 8-9 GeV linearly polarized photon beams. By extending the nearly non-existent meson data in photoproduction, as well as taking advantage of a spin 1 probe, we expect to be able to produce and study hybrid mesons with exotic, or non q-barq quantum numbers. The properties of these mesons yield information on the dynamic nature of gluons, and yield information on the issue of confinement.

  3. Controlling the Plasma Flow in the Miniaturized Cylindrical Hall Thruster

    International Nuclear Information System (INIS)

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


    A substantial narrowing of the plume of the cylindrical Hall thruster (CHT) was observed upon the enhancement of the electron emission from the hollow cathode discharge, which implies the possibility for the thruster efficiency increase due to the ion beam focusing. It is demonstrated that the miniaturized CHT can be operated in the non-self-sustained regime, with the discharge current limited by the cathode electron emission. The thruster operation in this mode greatly expands the range of the plasma and discharge parameters normally accessible for the CHT.

  4. Frazier Hall: The foundation failure that didn't

    International Nuclear Information System (INIS)

    Robinson, L.


    Frazier Hall is the oldest building on the Idaho State University campus--built before scientific foundation design was common. Its footings were clearly under designed, compared with modern practice. In fact, conventional analysis of the bearing capacity of two footings of this historic building indicate a failure condition. However, this structure is 60 years old and the foundation is still functioning. Possible reasons for the discrepancy between the analysis results and reality are posed and evaluated. This exercise gives some valuable insights into the process of foundation analysis and design. 7 refs., 5 figs

  5. New approach for measuring the microwave Hall mobility of semiconductors

    International Nuclear Information System (INIS)

    Murthy, D. V. B.; Subramanian, V.; Murthy, V. R. K.


    Measurement of Hall mobility in semiconductor samples using bimodal cavity method gives distinct advantages due to noncontact nature as well as the provision to measure anisotropic mobility. But the measurement approaches followed till now have a disadvantage of having high error values primarily due to the problem in evaluating the calibration constant of the whole experimental arrangement. This article brings out a new approach that removes such disadvantage and presents the calibration constant with 1% accuracy. The overall error in the carrier mobility values is within 5%

  6. Numerical investigation of closed-loop control for Hall accelerators

    International Nuclear Information System (INIS)

    Barral, S.; Miedzik, J.


    Low frequency discharge current oscillations in Hall accelerators are conventionally damped with external inductor-capacitor (LC) or resistor-inductor-capacitor (RLC) networks. The role of such network in the stabilization of the plasma discharge is investigated with a numerical model and the potential advantages of proportional-integral-derivative (PID) closed-loop control over RLC networks are subsequently assessed using either discharge voltage or magnetic field modulation. Simulations confirm the reduction of current oscillations in the presence of a RLC network, but suggest that PID control could ensure nearly oscillation-free operation with little sensitivity toward the PID settings.

  7. Spin-injection Hall effect in a planar photovoltaic cell

    Czech Academy of Sciences Publication Activity Database

    Wunderlich, J.; Irvine, A.C.; Sinova, J.; Park, B.G.; Zarbo, L.P.; Xu, X.L.; Kaestner, B.; Novák, Vít; Jungwirth, Tomáš


    Roč. 5, č. 9 (2009), s. 675-681 ISSN 1745-2473 R&D Projects: GA MŠk LC510; GA AV ČR KAN400100652; GA ČR GEFON/06/E002; GA ČR GEFON/06/E001 EU Projects: European Commission(XE) 215368 - SemiSpinNet Grant - others:AV ČR(CZ) AP0801 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : extraordinary Hall effect s * spintronics * photvoltaics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 15.491, year: 2009

  8. Modeling large underground experimental halls for the superconducting super collider

    International Nuclear Information System (INIS)

    Duan, F.; Mrugala, M.


    Geomechanical aspects of the excavation design, and analysis of two large underground experimental halls for the Superconducting Super Collider (SSC), being built in Texas, have been extensively investigated using computer modeling. Each chamber, measuring approximately 350 ft long, 110 ft wide, and 190 ft high, is to be excavated mainly through soft marl and overlying competent limestone. Wall stability is essential not only for ensuring excavation safety but also for meeting strict requirements for chamber stability over the 30-yr design life of the facility. Extensive numerical modeling has played a significant role in the selection of excavation methods, excavation sequence, and rock reinforcement systems. (Author)

  9. TOPICAL REVIEW: Spin current, spin accumulation and spin Hall effect

    Directory of Open Access Journals (Sweden)

    Saburo Takahashi and Sadamichi Maekawa


    Full Text Available Nonlocal spin transport in nanostructured devices with ferromagnetic injector (F1 and detector (F2 electrodes connected to a normal conductor (N is studied. We reveal how the spin transport depends on interface resistance, electrode resistance, spin polarization and spin diffusion length, and obtain the conditions for efficient spin injection, spin accumulation and spin current in the device. It is demonstrated that the spin Hall effect is caused by spin–orbit scattering in nonmagnetic conductors and gives rise to the conversion between spin and charge currents in a nonlocal device. A method of evaluating spin–orbit coupling in nonmagnetic metals is proposed.

  10. Scalar spin chirality and quantum hall effect on triangular lattices

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Ivar [Los Alamos National Laboratory; Batista, Cristian D [Los Alamos National Laboratory


    We study the Kondo Lattice and Hubbard models on a triangular lattice for band filling factor 3/4. We show that a simple non-coplanar chiral spin ordering (scalar spin chirality) is naturally realized in both models due to perfect nesting of the fermi surface. The resulting triple-Q magnetic ordering is a natural counterpart of the collinear Neel ordering of the half-filled square lattice Hubbard model. We show that the obtained chiral phase exhibits a spontaneous quantum Hall-effect with {sigma}{sub xy} = e{sup 2}/h.

  11. Shielding evaluation of neutron generator hall by Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Pujala, U.; Selvakumaran, T.S.; Baskaran, R.; Venkatraman, B. [Radiological Safety Division, Indira Gandhi Center for Atomic Research, Kalpakkam (India); Thilagam, L.; Mohapatra, D.K., E-mail: [Safety Research Institute, Atomic Energy Regulatory Board, Kalpakkam (India)


    A shielded hall was constructed for accommodating a D-D, D-T or D-Be based pulsed neutron generator (NG) with 4π yield of 10{sup 9} n/s. The neutron shield design of the facility was optimized using NCRP-51 methodology such that the total dose rates outside the hall areas are well below the regulatory limit for full occupancy criterion (1 μSv/h). However, the total dose rates at roof top, cooling room trench exit and labyrinth exit were found to be above this limit for the optimized design. Hence, additional neutron shielding arrangements were proposed for cooling room trench and labyrinth exits. The roof top was made inaccessible. The present study is an attempt to evaluate the neutron and associated capture gamma transport through the bulk shields for the complete geometry and materials of the NG-Hall using Monte Carlo (MC) codes MCNP and FLUKA. The neutron source terms of D-D, D-T and D-Be reactions are considered in the simulations. The effect of additional shielding proposed has been demonstrated through the simulations carried out with the consideration of the additional shielding for D-Be neutron source term. The results MC simulations using two different codes are found to be consistent with each other for neutron dose rate estimates. However, deviation up to 28% is noted between these two codes at few locations for capture gamma dose rate estimates. Overall, the dose rates estimated by MC simulations including additional shields shows that all the locations surrounding the hall satisfy the full occupancy criteria for all three types of sources. Additionally, the dose rates due to direct transmission of primary neutrons estimated by FLUKA are compared with the values calculated using the formula given in NCRP-51 which shows deviations up to 50% with each other. The details of MC simulations and NCRP-51 methodology for the estimation of primary neutron dose rate along with the results are presented in this paper. (author)

  12. A new US-UK diagnostic project: mood elevation and depression in first-year undergraduates at Oxford and Stanford universities. (United States)

    Chandler, R A; Wang, P W; Ketter, T A; Goodwin, G M


    To investigate differences in prevalence of mood elevation, distress and depression among first-year undergraduates at Oxford and Stanford universities. An online survey was sent to Oxford and Stanford first-year undergraduate students for two consecutive years in the winter of 2005 and 2006. Students completed a survey that assessed mood symptoms and medication use. Both universities had similar rates of distress by General Health Questionnaire (Oxford - 42.4%; Stanford - 38.3%), depression by Primary Care Evaluation of Mental Disorders (Oxford - 6.2%; Stanford - 6.6%), and psychotropic and non-psychotropic medication usage (psychotropic: Oxford - 1.5%; Stanford 3.5%; nonpsychotropic: Oxford - 13.3%; Stanford - 18%). Oxford had higher rates of mood elevation by Mood Disorder Questionnaire (MDQ) (Oxford - 4%; Stanford - 1.7%). Oxford and Stanford students have similar rates of mood distress, depression and general medication usage. Students at Oxford have a higher prevalence of MDQ scores that possibly indicate a bipolar disorder, while Stanford students are prescribed more psychotropics.

  13. A New Design of a Single-Device 3D Hall Sensor: Cross-Shaped 3D Hall Sensor

    Directory of Open Access Journals (Sweden)

    Wei Tang


    Full Text Available In this paper, a new single-device three-dimensional (3D Hall sensor called a cross-shaped 3D Hall device is designed based on the five-contact vertical Hall device. Some of the device parameters are based on 0.18 μm BCDliteTM technology provided by GLOBALFOUNDRIES. Two-dimensional (2D and 3D finite element models implemented in COMSOL are applied to understand the device behavior under a constant magnetic field. Besides this, the influence of the sensing contacts, active region’s depth, and P-type layers are taken into account by analyzing the distribution of the voltage along the top edge and the current density inside the devices. Due to the short-circuiting effect, the sensing contacts lead to degradation in sensitivities. The P-type layers and a deeper active region in turn are responsible for the improvement of sensitivities. To distinguish the P-type layer from the active region which plays the dominant role in reducing the short-circuiting effect, the current-related sensitivity of the top edge (Stop is defined. It is found that the short-circuiting effect fades as the depth of the active region grows. Despite the P-type layers, the behavior changes a little. When the depth of the active region is 7 μm and the thickness of the P-type layers is 3 μm, the sensitivities in the x, y, and z directions can reach 91.70 V/AT, 92.36 V/AT, and 87.10 V/AT, respectively.

  14. Dynamical scaling analysis of the optical Hall conductivity in the graphene quantum Hall system with various types of disorder

    International Nuclear Information System (INIS)

    Morimoto, Takahiro; Aoki, Hideo; Avishai, Yshai


    Dynamical scaling of the optical Hall conductivity σ xy (ε F , ω) at the n = 0 Landau level in graphene is analyzed for the 2D effective Dirac fermion and honeycomb lattice models with various types of disorder. In the Dirac fermion model with potential disorder, σ xy (ε F , ω) obeys a well-defined dynamical scaling, characterized by the localization exponent ν and the dynamical critical exponent z. In sharp distinction, scaling behavior of σ xy (ε F , ω) in the honeycomb lattice model with bond disorder (preserving chiral symmetry), becomes anomalous.

  15. Analysis of Wien filter spectra from Hall thruster plumes (United States)

    Huang, Wensheng; Shastry, Rohit


    A method for analyzing the Wien filter spectra obtained from the plumes of Hall thrusters is derived and presented. The new method extends upon prior work by deriving the integration equations for the current and species fractions. Wien filter spectra from the plume of the NASA-300M Hall thruster are analyzed with the presented method and the results are used to examine key trends. The new integration method is found to produce results slightly different from the traditional area-under-the-curve method. The use of different velocity distribution forms when performing curve-fits to the peaks in the spectra is compared. Additional comparison is made with the scenario where the current fractions are assumed to be proportional to the heights of peaks. The comparison suggests that the calculated current fractions are not sensitive to the choice of form as long as both the height and width of the peaks are accounted for. Conversely, forms that only account for the height of the peaks produce inaccurate results. Also presented are the equations for estimating the uncertainty associated with applying curve fits and charge-exchange corrections. These uncertainty equations can be used to plan the geometry of the experimental setup.

  16. Low-Mass, Low-Power Hall Thruster System (United States)

    Pote, Bruce


    NASA is developing an electric propulsion system capable of producing 20 mN thrust with input power up to 1,000 W and specific impulse ranging from 1,600 to 3,500 seconds. The key technical challenge is the target mass of 1 kg for the thruster and 2 kg for the power processing unit (PPU). In Phase I, Busek Company, Inc., developed an overall subsystem design for the thruster/cathode, PPU, and xenon feed system. This project demonstrated the feasibility of a low-mass power processing architecture that replaces four of the DC-DC converters of a typical PPU with a single multifunctional converter and a low-mass Hall thruster design employing permanent magnets. In Phase II, the team developed an engineering prototype model of its low-mass BHT-600 Hall thruster system, with the primary focus on the low-mass PPU and thruster. The goal was to develop an electric propulsion thruster with the appropriate specific impulse and propellant throughput to enable radioisotope electric propulsion (REP). This is important because REP offers the benefits of nuclear electric propulsion without the need for an excessively large spacecraft and power system.

  17. Theoretical study of spin Hall effect in conjugated Organic semiconductors (United States)

    Mahani, M. R.; Delin, A.

    The spin Hall effect (SHE), a direct conversion between electronic and spin currents, is a rapidly growing branch of spintronics. The study of SHE in conjugated polymers has gained momentum recently due to the weak spin-orbit couplings and hyperfine interactions in these materials. Our calculations of SHE based on the recent work, are the result of the misalignment of pi-orbitals in triads consisting of three molecules. In disordered organics, where the electronic conduction is through hopping of the electrons among randomly oriented molecules, instead of identifying a hopping triad to represent the entire system, we numerically solve the master equations for electrical and spin hall conductivities by summing the contributions from all triads in a sufficiently large system. The interference between the direct and indirect hoppings in these triads leads to SHE proportional to the orientation vector of molecule at the first order of spin-orbit coupling. Hence, our results show, the degree of molecular alignment as well as the strength of the spin-orbit coupling can be used to control the SHE in organics.

  18. Nonlinear magnetotransport theory and Hall induced resistance oscillations in graphene. (United States)

    Gutiérrez-Jáuregui, R; Torres, M


    The quantum oscillations of nonlinear magnetoresistance in graphene that occur in response to a dc current bias are investigated. We present a theoretical model for the nonlinear magnetotransport of graphene carriers. The model is based on the exact solution of the effective Dirac equation in crossed electric and magnetic fields, while the effects of randomly distributed impurities are perturbatively added. To compute the nonlinear current effects, we develop a covariant formulation of the migration center theory. The current is calculated for short- and large-range scatterers. The analysis of the differential resistivity in the large magnetic field region, shows that the extrema of the Shubnikov de Hass oscillations invert when the dc currents exceed a threshold value. These results are in good agreement with experimental observations. In the small magnetic field regime, corresponding to large filling factors, the existence of Hall induced resistance oscillations are predicted for ultra clean graphene samples. These oscillations originate from Landau-Zener tunneling between Landau levels, that are tilted by the strong electric Hall field.

  19. Anomalous DC Hall response in noncentrosymmetric tilted Weyl semimetals (United States)

    Mukherjee, S. P.; Carbotte, J. P.


    Weyl nodes come in pairs of opposite chirality. For broken time reversal symmetry (TR) they are displaced in momentum space by {Q} and the anomalous DC Hall conductivity σxy is proportional to {Q} at charge neutrality. For finite doping there are additive corrections to σxy which depend on the chemical potential as well as on the tilt (C ) of the Dirac cones and on their relative orientation. If inversion symmetry (I) is also broken the Weyl nodes are shifted in energy by an amount Q0 . This introduces further changes in σxy and we provide simple analytic formulas for these modifications for both type I (Ctype II (C>1 , overtilted) Weyl. For type I when the Weyl nodes have equal magnitude but oppositely directed tilts, the correction to σxy is proportional to the chemical potential μ and completely independent of the energy shift Q0 . When instead the tilts are parallel, the correction is linear in Q0 and μ drops out. For type II the corrections involve both μ and Q0 , are nonlinear and also involve a momentum cut off. We discuss the implied changes to the Nernst coefficient and to the thermal Hall effect of a finite Q0 .

  20. Photonic spin Hall effect in metasurfaces: a brief review

    Directory of Open Access Journals (Sweden)

    Liu Yachao


    Full Text Available The photonic spin Hall effect (SHE originates from the interplay between the photon-spin (polarization and the trajectory (extrinsic orbital angular momentum of light, i.e. the spin-orbit interaction. Metasurfaces, metamaterials with a reduced dimensionality, exhibit exceptional abilities for controlling the spin-orbit interaction and thereby manipulating the photonic SHE. Spin-redirection phase and Pancharatnam-Berry phase are the manifestations of spin-orbit interaction. The former is related to the evolution of the propagation direction and the latter to the manipulation with polarization state. Two distinct forms of splitting based on these two types of geometric phases can be induced by the photonic SHE in metasurfaces: the spin-dependent splitting in position space and in momentum space. The introduction of Pacharatnam-Berry phases, through space-variant polarization manipulations with metasurfaces, enables new approaches for fabricating the spin-Hall devices. Here, we present a short review of photonic SHE in metasurfaces and outline the opportunities in spin photonics.

  1. Chiral Luttinger liquids at the fractional quantum Hall edge (United States)

    Chang, A. M.


    The edges of quantum Hall fluids behave as one-dimensional conductors. This article reviews electron transport into these edge states, covering both the theory based on the chiral Luttinger liquid and the experimental findings using electron tunneling as the probe. The first part of the review presents a basic description of this theory, including a derivation of the density of states, to provide a framework and language for discussing the experimental observations. The signature of the chiral Luttinger liquid is a power-law behavior for the density of states and the tunneling conductances. Experimentally, two techniques have been applied to study the tunneling conductance, using a gated point contact between two quantum Hall edges, or using a cleaved-edge barrier between an edge and a normal conductor. The point-contact method exhibits resonant tunneling, which appears to show some aspects of the Luttinger liquid, and the cleaved-edge method has yielded clear power-law dependences in the off-resonance conductances. Power-law behavior over many orders of magnitude is observed, confirming the Luttinger-liquid character of the edge states. However, the power-law exponents, while in agreement with finite-size numerical calculations, can differ from the universal values predicted by the Chern-Simon field theory. This disagreement is still not well understood. The review concludes with a brief survey of other one-dimensional conductors that have been studied to look for characteristics of the nonchiral Tomonaga-Luttinger liquid.

  2. Non-Abelian fermionization and fractional quantum Hall transitions (United States)

    Hui, Aaron; Mulligan, Michael; Kim, Eun-Ah


    There has been a recent surge of interest in dualities relating theories of Chern-Simons gauge fields coupled to either bosons or fermions within the condensed matter community, particularly in the context of topological insulators and the half-filled Landau level. Here, we study the application of one such duality to the long-standing problem of quantum Hall interplateaux transitions. The key motivating experimental observations are the anomalously large value of the correlation length exponent ν ≈2.3 and that ν is observed to be superuniversal, i.e., the same in the vicinity of distinct critical points [Sondhi et al., Rev. Mod. Phys. 69, 315 (1997), 10.1103/RevModPhys.69.315]. Duality motivates effective descriptions for a fractional quantum Hall plateau transition involving a Chern-Simons field with U (Nc) gauge group coupled to Nf=1 fermion. We study one class of theories in a controlled limit where Nf≫Nc and calculate ν to leading nontrivial order in the absence of disorder. Although these theories do not yield an anomalously large exponent ν within the large Nf≫Nc expansion, they do offer a new parameter space of theories that is apparently different from prior works involving Abelian Chern-Simons gauge fields [Wen and Wu, Phys. Rev. Lett. 70, 1501 (1993), 10.1103/PhysRevLett.70.1501; Chen et al., Phys. Rev. B 48, 13749 (1993), 10.1103/PhysRevB.48.13749].

  3. Parametric Investigation of Miniaturized Cylindrical and Annular Hall Thrusters

    International Nuclear Information System (INIS)

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


    Conventional annular Hall thrusters become inefficient when scaled to low power. An alternative approach, a 2.6-cm miniaturized cylindrical Hall thruster with a cusp-type magnetic field distribution, was developed and studied. Its performance was compared to that of a conventional annular thruster of the same dimensions. The cylindrical thruster exhibits discharge characteristics similar to those of the annular thruster, but it has a much higher propellant ionization efficiency. Significantly, a large fraction of multi-charged xenon ions might be present in the outgoing ion flux generated by the cylindrical thruster. The operation of the cylindrical thruster is quieter than that of the annular thruster. The characteristic peak in the discharge current fluctuation spectrum at 50-60 kHz appears to be due to ionization instabilities. In the power range 50-300 W, the cylindrical and annular thrusters have comparable efficiencies (15-32%) and thrusts (2.5-12 mN). For the annular configuration, a voltage less than 200 V was not sufficient to sustain the discharge at low propellant flow rates. The cylindrical thruster can operate at voltages lower than 200 V, which suggests that a cylindrical thruster can be designed to operate at even smaller power

  4. Unconventional phases of attractive Fermi gases in synthetic Hall ribbons (United States)

    Ghosh, Sudeep Kumar; Greschner, Sebastian; Yadav, Umesh K.; Mishra, Tapan; Rizzi, Matteo; Shenoy, Vijay B.


    An innovative way to produce quantum Hall ribbons in a cold atomic system is to use M hyperfine states of atoms in a one-dimensional optical lattice to mimic an additional "synthetic dimension." A notable aspect here is that the SU(M ) symmetric interaction between atoms manifests as "infinite ranged" along the synthetic dimension. We study the many-body physics of fermions with SU(M ) symmetric attractive interactions in this system using a combination of analytical field theoretic and numerical density-matrix renormalization-group methods. We uncover the rich ground-state phase diagram of the system, including unconventional phases such as squished baryon fluids, shedding light on many-body physics in low dimensions. Remarkably, changing the parameters entails interesting crossovers and transition; e.g., we show that increasing the magnetic field (that produces the Hall effect) converts a "ferrometallic" state at low fields to a "squished baryon superfluid" (with algebraic pairing correlations) at high fields. We also show that this system provides a unique opportunity to study quantum phase separation in a multiflavor ultracold fermionic system.

  5. Spatially resolved Hall effect measurement in a single semiconductor nanowire (United States)

    Storm, Kristian; Halvardsson, Filip; Heurlin, Magnus; Lindgren, David; Gustafsson, Anders; Wu, Phillip M.; Monemar, Bo; Samuelson, Lars


    Efficient light-emitting diodes and photovoltaic energy-harvesting devices are expected to play an important role in the continued efforts towards sustainable global power consumption. Semiconductor nanowires are promising candidates as the active components of both light-emitting diodes and photovoltaic cells, primarily due to the added freedom in device design offered by the nanowire geometry. However, for nanowire-based components to move past the proof-of-concept stage and be implemented in production-grade devices, it is necessary to precisely quantify and control fundamental material properties such as doping and carrier mobility. Unfortunately, the nanoscale geometry that makes nanowires interesting for applications also makes them inherently difficult to characterize. Here, we report a method to carry out Hall measurements on single core-shell nanowires. Our technique allows spatially resolved and quantitative determination of the carrier concentration and mobility of the nanowire shell. As Hall measurements have previously been completely unavailable for nanowires, the experimental platform presented here should facilitate the implementation of nanowires in advanced practical devices.

  6. Quantum spin Hall effect in twisted bilayer graphene (United States)

    Finocchiaro, F.; Guinea, F.; San-Jose, P.


    Motivated by a recent experiment (Sanchez-Yamagishi et al 2016 Nat. Nanotechnol. 214) reporting evidence of helical spin-polarized edge states in layer-biased twisted bilayer graphene under a magnetic flux, we study the possibility of stabilising a quantum spin Hall (QSH) phase in such a system, without Zeeman or spin-orbit couplings, and with a QSH gap induced instead by electronic interactions. We analyse how magnetic flux, electric field, interlayer rotation angle, and interactions (treated at a mean field level) combine to produce a pseudo-QSH with broken time-reversal symmetry, and spin-polarized helical edge states. The effect is a consequence of a robust interaction-induced ferrimagnetic ordering of the quantum Hall ground state under an interlayer bias, provided the two rotated layers are effectively decoupled at low energies. We discuss in detail the electronic structure and the constraints on system parameters, such as the angle, interactions and magnetic flux, required to reach the pseudo-QSH phase. We find, in particular, that purely local electronic interactions are not sufficient to account for the experimental observations, which demand at least nearest-neighbour interactions to be included.

  7. Anomalous Hall effect in Fe/Au multilayers

    KAUST Repository

    Zhang, Q.


    To understand the interfacial scattering effect on the anomalous Hall effect (AHE), we prepared multilayers of (Fe(36/n)nm/Au(12/n)nm)n using an e-beam evaporator. This structure design allowed us to investigate the effect of interfacial scattering on the AHE, while keeping the samples\\' thickness and composition unchanged. We measured the (magneto)transport properties of the samples in a wide temperature range (10–310 K) with magnetic fields up to 50 kOe. We found that the scaling between the anomalous Hall resistivity (ρAHE) and longitudinal resistivity (ρxx) can be roughly described by ρAHE∼ργxx with γ=2.65±0.10 and 1.90 ± 0.04 for samples from n=1 to n=4 and samples from n=4 to n=12, respectively. Our quantitative analysis results showed that the interfacial scattering suppresses the contribution of the intrinsic mechanism and gives rise to a side-jump contribution.

  8. Assessment of Pole Erosion in a Magnetically Shielded Hall Thruster (United States)

    Mikellides, Ioannis G.; Ortega, Alejandro L.


    Numerical simulations of a 6-kW laboratory Hall thruster called H6 have been performed to quantify the erosion rate at the inner pole. The assessments have been made in two versions of the thruster, namely the unshielded (H6US) and magnetically shielded (H6MS) configurations. The simulations have been performed with the 2-D axisymmetric code Hall2De which employs a new multi-fluid ion algorithm to capture the presence of low-energy ions in the vicinity of the poles. It is found that the maximum computed erosion rate at the inner pole of the H6MS exceeds the measured rate of back-sputtered deposits by 4.5 times. This explains only part of the surface roughening that was observed after a 150-h wear test, which covered most of the pole area exposed to the plasma. For the majority of the pole surface the computed erosion rates are found to be below the back-sputter rate and comparable to those in the H6US which exhibited little to no sputtering in previous tests. Possible explanations for the discrepancy are discussed.

  9. The variability in Oxford hip and knee scores in the preoperative period: is there an ideal time to score? (United States)

    Quah, C; Holmes, D; Khan, T; Cockshott, S; Lewis, J; Stephen, A


    Background All NHS-funded providers are required to collect and report patient-reported outcome measures for hip and knee arthroplasty. Although there are established guidelines for timing such measures following arthroplasty, there are no specific time-points for collection in the preoperative period. The primary aim of this study was to identify whether there was a significant amount of variability in the Oxford hip and knee scores prior to surgical intervention when completed in the outpatient clinic at the time of listing for arthroplasty or when completed at the preoperative assessment clinic. Methods A prospective cohort study of patients listed for primary hip or knee arthroplasty was conducted. Patients were asked to fill in a preoperative Oxford score in the outpatient clinic at the time of listing. They were then invited to fill in the official outcome measures questionnaire at the preoperative assessment clinic. The postoperative Oxford score was then completed when the patient was seen again at their postoperative follow up in clinic. Results Of the total of 109 patients included in this study period, there were 18 (17%) who had a worse score of 4 or more points difference and 43 (39.4%) who had an improvement of 4 or more points difference when the scores were compared between time of listing at the outpatient and at the preoperative assessment clinic. There was a statistically significant difference (P = 0.0054) in the mean Oxford scores. Conclusions The results of our study suggest that there should be standardisation of timing for completing the preoperative patient-reported outcome measures.

  10. The Role of Social Influence on How Residence Hall Inhabitants Respond to Fire Alarms (United States)

    Leytem, Michael; Stark, Emily


    College resident halls pose a threat for a catastrophic event in the case of fire, but little research has examined potential influences on students' responses to fire alarms, particularly the role of social influence in affecting their behaviors. In the current study, residence hall inhabitants reported their knowledge about fire safety, their…

  11. First Year Evaluation IPI Mathematics Project, Hall School 1969-1970. (United States)

    Hestwood, Diana

    A three-year Individually Prescribed Instruction (IPI) project in mathematics was initiated at Hall Elementary School in Minneapolis, September 1969, under ESEA Title I funding. Hall School is in a low income area of the city and nearly all children in the project were considered educationally disadvantaged. First year evaluation results show that…

  12. Purposeful naming: The case of beer halls named during both the ...

    African Journals Online (AJOL)

    This article examines the reasons behind names given to beer halls from their inception in colonial Rhodesia to present day Zimbabwe. To achieve this goal, it analyses names of beer halls, beer outlets built in the former townships of colonial Rhodesia (now called high-density suburbs), and those built at growth points, ...

  13. War Heroes/Krygshelde LT.KDR. D.A. HALL, DIE GROOTHARTIGE ...

    African Journals Online (AJOL)

    This article recalls the part lieutenant-commander. D.A. "Stoker" Hall, one of the South African naval heroes of World War II, and his last command, the fregate Natal, has played in the Battle of the Atlantic. Natal was one of the two South African warships that sank enemy submarines - and. Lt Cmdr Hall was the only South ...

  14. Hall effect in the normal phase of the organic superconductor (TMTSF)2PF6

    DEFF Research Database (Denmark)

    Moser, J.; Cooper, J.R.; Jerome, D.


    We report accurate Hall effect measurements performed in the normal phase of the quasi-one-dimensional organic conductor (TMTSF)(2)PF(6) at ambient pressure. The Hall coefficient is found to be strongly temperature dependent all the way from 300 K down to the spin density wave onset arising around...

  15. Hallé SHINE on Manchester: Evaluation Report and Executive Summary (United States)

    Menzies, Victoria; Kasim, Adetayo; Kokotsaki, Dimitra; Hewitt, Catherine; Akhter, Nasima; Collyer, Clare; Younger, Kirsty; Wiggins, Andy; Torgerson, Carole


    The "Hallé SHINE on Manchester" (HSoM) programme is a Saturday school educational programme designed to increase the reading and maths attainment, as well as engagement with school, of underachieving and disadvantaged pupils at Key Stage 2. Developed in collaboration between the SHINE Trust and Hallé Orchestra, the intervention provides…

  16. A study of cylindrical Hall thruster for low power space applications

    Energy Technology Data Exchange (ETDEWEB)

    Y. Raitses; N.J. Fisch; K.M. Ertmer; C.A. Burlingame


    A 9 cm cylindrical thruster with a ceramic channel exhibited performance comparable to the state-of-the-art Hall thrusters at low and moderate power levels. Significantly, its operation is not accompanied by large amplitude discharge low frequency oscillations. Preliminary experiments on a 2 cm cylindrical thruster suggest the possibility of a high performance micro Hall thruster.

  17. The (Anomalous) Hall Magnetometer as an Analysis Tool for High Density Recording Media

    NARCIS (Netherlands)

    de Haan, S.; de Haan, S.; Lodder, J.C.; Popma, T.J.A.


    In this work an evaluation tool for the characterization of high-density recording thin film media is discussed. The measurement principles are based on the anomalous and the planar Hall effect. We used these Hall effects to characterize ferromagnetic Co-Cr films and Co/Pd multilayers having

  18. On-Chip Magnetorelaxometry Using Planar Hall Effect Magnetic Field Sensors

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard

    with streptavidin coated beads and biotin-conjugated bovine serum albumin show that planar Hall effect sensors can detect the presence of biotin-conjugated bovine serum albumin in the nanomolar range. Finally, measurements are performed to detect DNA-coils formed by rolling amplification using planar Hall effect...

  19. A free boundary problem for planar compressible Hall-magnetohydrodynamic equations (United States)

    Tao, Qiang; Yang, Ying; Gao, Jincheng


    In this paper, we study the existence and uniqueness of the global classical solution for the planar compressible Hall-magnetohydrodynamic equations with large initial data. The system is supplemented with free boundary and smooth initial conditions. The proof relies on the bounds of the density and the skew-symmetric structure of the Hall term.

  20. "Are You as Hard as 50 Cent?" Negotiating Race and Masculinity in the Residence Halls (United States)

    Jaggers, Dametraus; Iverson, Susan V.


    In a qualitative study of Black undergraduate men at a predominantly White university in the Midwest, participants shared their experiences in residence halls, including roommate conflicts, interracial tensions, and disagreements with residence hall staff. This article focuses on Black male undergraduates' negotiation of racialized conceptions of…