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Sample records for grenoble city hall

  1. 9. Historic American Buildings Survey, BINGHAMTON CITY HALL, PHOTOCOPY OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Historic American Buildings Survey, BINGHAMTON CITY HALL, PHOTOCOPY OF ORIGINAL COMPETITION DRAWING (GENERAL PERSPECTIVE) - 1896 FROM THE OFFICE OF THE CITY ENGINEER, BINGHAMTON, NEW YORK. - Binghamton City Hall, Collier Street, Binghamton, Broome County, NY

  2. 10. Historic American Buildings Survey, BINGHAMTON CITY HALL, PHOTOCOPY OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Historic American Buildings Survey, BINGHAMTON CITY HALL, PHOTOCOPY OF ORIGINAL COMPETITION DRAWING OF A LONGITUDINAL SECTION - 1896 FROM THE OFFICE OF THE CITY ENGINEER, BINGHAMTON, NEW YORK. - Binghamton City Hall, Collier Street, Binghamton, Broome County, NY

  3. 13. Historic American Buildings Survey, BINGHAMTON CITY HALL, PHOTOCOPY OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Historic American Buildings Survey, BINGHAMTON CITY HALL, PHOTOCOPY OF ORIGINAL COMPETITION DRAWING OF FIRST FLOOR PLAN - 1896 FROM THE OFFICE OF THE CITY ENGINEER, BINGHAMTON, NEW YORK. - Binghamton City Hall, Collier Street, Binghamton, Broome County, NY

  4. Engaging City Hall: Children as Citizens

    ERIC Educational Resources Information Center

    Krechevsky, Mara; Mardell, Ben; Romans, Angela N.

    2014-01-01

    In this article, the authors suggest that current notions of advocacy in early childhood education should be expanded to include a view of young children as citizens. The authors ground their discussion in a how-to book project in Providence, Rhode Island, consider different concepts of children and citizenship, share commentary from City Hall and…

  5. High Tech Images. San Bernardino City Hall

    ERIC Educational Resources Information Center

    McCoy, Esther

    1974-01-01

    A part of San Bernardino's larger redevelopment plan, the new City Hall has helped revitalize the downtown core. The solar bronze glass-surfaced structure, called a 6-story street, is the shape of the street which was closed to form the site. (Author/MF)

  6. Contextual view of ILWU Hall, facing east, with the city ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view of ILWU Hall, facing east, with the city of Port Hueneme visible in the background - International Longshoremen's & Warehousemen's Union Hall, Naval Civil Engineering Laboratory, Port Hueneme Road, Port Hueneme, Ventura County, CA

  7. 3. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore printed by authority of the mayor and city council,1877,showing plan of first floor - Baltimore City Hall, Holliday Street, Baltimore, Independent City, MD

  8. 4. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore printed by authority of the mayor and city council,1877,showing section on line C-D - Baltimore City Hall, Holliday Street, Baltimore, Independent City, MD

  9. 1. photocopy of print by A. Hoen &Co.,1877, City Hall,Baltimore ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. photocopy of print by A. Hoen &Co.,1877, City Hall,Baltimore printed by authority of the mayor and city council,1877, showing east (main) front and south front - Baltimore City Hall, Holliday Street, Baltimore, Independent City, MD

  10. 2. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore printed by authority of the mayor and city council,1877,showing plan of roof and dome - Baltimore City Hall, Holliday Street, Baltimore, Independent City, MD

  11. Inter-comparison of source apportionment models for the estimation of wood burning aerosols during wintertime in an Alpine city (Grenoble, France)

    NASA Astrophysics Data System (ADS)

    Favez, O.; El Haddad, I.; Piot, C.; Boréave, A.; Abidi, E.; Marchand, N.; Jaffrezo, J.-L.; Besombes, J.-L.; Personnaz, M.-B.; Sciare, J.; Wortham, H.; George, C.; D'Anna, B.

    2010-06-01

    The emission of organic aerosols (OA) in the ambient air by residential wood burning is nowadays a subject of great scientific concern and a growing number of studies aim at apportioning the influence of such emissions on urban air quality. In the present study, results obtained using two commonly-used source apportionment models, i.e., Chemical Mass Balance (CMB, performed with off-line filter measurements) and Positive Matrix Factorization (PMF, applied to Aerosol Mass Spectrometer measurements), as well as using the recently-proposed Aethalometer model (based on the measurement of the aerosol light absorption at different wavelengths) are inter-compared. This work is performed using field data obtained during the winter season (14 to 29 January 2009) at an urban background site of a French Alpine city (Grenoble). Converging results from the different models indicate a major contribution of wood burning organic aerosols (OMwb) to the ambient aerosol organic fraction, with mean OMwb contributions to total OA of 68%, 61% and 37% for the CMB, the Aethalometer and the AMS-PMF models respectively, during the period when the three modelling studies overlapped (12 days). Quantitative discrepancies might notably be due to the overestimation of OMwb calculated by the CMB due to the loss of semi-volatile compounds from sources to receptor site, as well as to the accounting of oxidized primary wood burning organic (OPOAwb) aerosols within the Oxygenated Organic Aerosol (OOA) PMF-factor. This OOA factor accounts on average for about 50% of total OM, while non-combustion sources contribute to about 25% and 28% of total OM according to the CMB and Aethalometer models respectively. Each model suggests a mean contribution of fossil fuel emissions to total OM of about 10%. A good agreement is also obtained for the source apportionment of elemental carbon (EC) by both the CMB and the Aethalometer models, with fossil fuel emissions representing on average more than 80% of total EC.

  12. Inter-comparison of source apportionment models for the estimation of wood burning aerosols during wintertime in an Alpine city (Grenoble, France)

    NASA Astrophysics Data System (ADS)

    Favez, O.; El Haddad, I.; Piot, C.; Boréave, A.; Abidi, E.; Marchand, N.; Jaffrezo, J.-L.; Besombes, J.-L.; Personnaz, M.-B.; Sciare, J.; Wortham, H.; George, C.; D'Anna, B.

    2010-01-01

    The emission of organic aerosols (OA) in the ambient air by residential wood burning is nowadays a subject of great scientific concern and a growing number of studies aim at apportioning the influence of such emissions on urban air quality. In the present study, results obtained using two commonly-used source apportionment models, i.e., Chemical Mass Balance (CMB, performed with off-line filter measurements) and Positive Matrix Factorization (PMF, applied to aerosol mass spectrometer measurements), as well as using the recently-proposed aethalometer model (based on the measurement of the aerosol light absorption at different wavelengths) are inter-compared. This work is performed using field data obtained during the winter season (14 to 30 January 2009) at an urban background site of a French Alpine city (Grenoble). Converging results from the different models indicate a major contribution of wood burning organic aerosols (OMwb) to the organic fraction, with mean OMwb contributions to total OA of about 67%, 60% and 38% for the CMB, the aethalometer and the AMS-PMF models, respectively. Quantitative discrepancies might notably be due to the overestimation of OMwb calculated by the CMB due to the loss of semi-volatile compounds from sources to receptor site, as well as to the accounting of oxidized primary wood burning organic (OPOAwb) aerosols within the Oxygenated Organic Aerosol (OOA) PMF-factor. This OOA factor accounts on average for about 50% of total OM, while non-combustion sources contribute to about 25% and 28% of total OM according to the CMB and aethalometer models, respectively. Each model suggests a mean contribution of fossil fuel emissions to total OM of about 10%. A good agreement is also obtained for the source apportionment of elemental carbon (EC) by both the CMB and aethalometer models, with fossil fuel emissions representing on average more than 80% of total EC.

  13. Providing for Disabled Students: University of Grenoble, France.

    ERIC Educational Resources Information Center

    PEB Exchange, 2000

    2000-01-01

    Examines how France's University of Grenoble provides for its disabled students in its residence halls, including a description of the university's service for disabled service. A hospital/education center where disabled students can receive care and physiotherapy while attending school is highlighted. (GR)

  14. Study of marble deterioration at City Hall, Schenectady, New York

    SciTech Connect

    Cheng, R.J.; Castillo, R.

    1984-01-01

    Constructed in 1930 at a cost of over one million dollars, the City Hall in Schenectady, New York, is listed in the U.S. Register of Historical Buildings. The masonry materials were the finest available at the time of construction; granite, fire hardened exterior brick and Vermont marble - Imperical Danby, an equivalent to Carrara marble from Italy. It is known today that the lack of impurities in the Imperial Danby leads to weak crystalline properties. Cleaned with water, sponges and stiff brushes upon completion of construction, the exterior was not cleaned over a fifty-year period. The research indicated that the marble grains are being structurally weakened by a chemical conversion process of marble to gypsum crystals. The surface zone of chemical activity (2-5 mm) shows the presence of fly ash and iron particles and points to the possibility of a catalytic mechanism for the conversion of sulfur dioxide to sulfate. This research has established symptoms which are consistent with prior reported research into building material deterioration. However, the results presented are not supportive of one mechanism over another.

  15. Stop Tobacco in Restaurants: Fifth Grade Students STIR City Hall

    ERIC Educational Resources Information Center

    Morris, Ronald Vaughan

    2008-01-01

    This article discusses a campaign called STIR: Stop Tobacco in Restaurants, that was started by fourth and fifth grade students. The goal was to end smoking in public places, including restaurants, bowling alleys, sports bars, and pool halls. For two years they motivated their peers, coordinated an information campaign to urge kids and adults to…

  16. Characterization of Compounds Formed and added on surface of outdoor Seville city hall

    NASA Astrophysics Data System (ADS)

    Robador, Maria Dolores; Alcalde, Manuel; Arroyo, Fatima; Albardonedo, Antonio; Perez-Rodriguez, Jose Luis

    2013-04-01

    The building of the City Hall of Seville constitutes one of the samples more important of the architecture plateresque in Andalusia. For centuries the stone façade has suffered different stages of restoration. These treatments joined the effects of the environmental pollution are responsible for formation and deposition of different chemical compounds on the surface of the monuments. This study will supply information of the environmental effects on the rock, and the treatments that have been performed in previous interventions. The petrographic study showed the presence of a carbonate rock of thin grain constituted essentially by bioclastos and fine sand. The study by scanning electron microscopy showed a compact and continuous cover that suggested a polymer layer. The infrared spectroscopy study confirmed presence of acrylic resin. This resin covered sometimes a black crust constituted by alkanes characterized by mass spectrometry. In addition was found nodules constitutes by C, Ca, Fe, Si and Ca. These compounds appeared with gypsum and were attributed to environment contamination produced by combustion. Materials were observed that cover volumetric lagoons for losses of pieces or were used to fix fragments of stones that were free or displaced. The study by X-ray diffraction and infrared spectroscopy confirmed the presence of gypsum. Mortars constituted by calcite (60%) and inert material (40%; mainly quartz, feldspar and mica) were also characterized. In flute of the stone was found a black crust under which appeared a yellowish layer. The portable X-ray fluorescence and X-ray diffraction confirmed the presence of gypsum produced by environmental contamination. Gypsum was also found in the interior of the stone confirming that this mineral has emigrated due the high porosity of the stone. In some zones of the façade was detected some possible wall paintings. Cross-sections were prepared and studied by optical and scanning electron microscopes. A layer of

  17. Unique seismic controlled sources: Using the demolition of smelter tower stacks and the City Hall in El Paso,TX for a seismic survey

    NASA Astrophysics Data System (ADS)

    Montana, C. J.; Gonzalez-Huizar, H.; Kaip, G.; Velasco, A. A.

    2013-12-01

    On April 13, 2013 the city of El Paso, TX demolished two old smelter smoke stacks leftover from the smelting days of ASARCO and the following day, demolished the City Hall building. These two events provided a unique opportunity to utilize two complex (demolition of two smoke stack towers plus a sequence of explosions at source site 1 and a sequence of explosions and the demolition of a building at source site 2) seismic sources to provide information about the uppermost subsurface of the surrounding areas of the City of El Paso. We deployed an array of 46 seismographs (Reftek Texans) connected to 4 Hz geophones along 3 survey lines: a NW to SE line extending from the ASARCO smokestacks site through City Hall and extending to a station location near the border (providing a revered profile); a W to E line extending from the ASARCO smoke stack location towards an end point in central El Paso; and a SSW to NNE line from City Hall towards a station location adjacent to the Franklin Mountains Mountain Range. The maximum source to receiver offset is over 5 km. The seismographs where deployed in an urban setting resulting in a challenging deployment in terms of security and integrity of the instruments. The recording mode was set to continuous from several hours before the stacks demolition to several hours after the City Hall building demolition. The data acquired is rich with many phases recorded. The main towers impact is clearly recorded along the length of all lines even though it was at the longest offset. The City Hall demolition site is located at a more central position that made it easier to be recorded. The complexity of the sources will require extensive signal processing to separate and determine specific phases. We will be using the line to develop a preliminary 2-D velocity model, which will be used to identify any faults and other geological structures buried beneath the deep river sediments near downtown El Paso.

  18. The Effect of Selected Cleaning Techniques on Berkshire Lee Marble: A Scientific Study at Philadelphia City Hall

    USGS Publications Warehouse

    Mossotti, Victor G.; Eldeeb, A. Raouf; Fries, Terry L.; Coombs, Mary Jane; Naude, Virginia N.; Soderberg, Lisa; Wheeler, George S.

    2002-01-01

    This report describes a scientific investigation of the effects of eight different cleaning techniques on the Berkshire Lee marble component of the facade of the East Center Pavilion at Philadelphia City Hall; the study was commissioned by the city of Philadelphia. The eight cleaning techniques evaluated in this study were power wash (proprietary gel detergent followed by water rinse under pressure), misting (treatment with potable, nebulized water for 24-36 hours), gommage (proprietary Thomann-Hanry low-pressure, air-driven, small-particle, dry abrasion), combination (gommage followed by misting), Armax (sodium bicarbonate delivered under pressure in a water wash), JOS (dolomite powder delivered in a low-pressure, rotary-vortex water wash), laser (thermal ablation), and dry ice (powdered-dry-ice abrasion delivered under pressure). In our study approximately 160 cores were removed from the building for laboratory analysis. We developed a computer program to analyze scanning-electron-micrograph images for the microscale surface roughness and other morphologic parameters of the stone surface, including the near-surface fracture density of the stone. An analysis of more than 1,100 samples cut from the cores provided a statistical basis for crafting the essential elements of a reduced-form, mixed-kinetics conceptual model that represents the deterioration of calcareous stone in terms of self-organized soiling and erosion patterns. This model, in turn, provided a basis for identifying the variables that are affected by the cleaning techniques and for evaluating the extent to which such variables influence the stability of the stone. The model recognizes three classes of variables that may influence the soiling load on the stone, including such exogenous environmental variables as airborne moisture, pollutant concentrations, and local aerodynamics, and such endogenous stone variables as surface chemistry and microstructure (fracturing, roughness, and so on). This study

  19. Spectral Element Modeling of 3D Site Effects in the Alpine Valley of Grenoble, France.

    NASA Astrophysics Data System (ADS)

    Chaljub, E.; Cornou, C.; Gueguen, P.; Causse, M.; Komatitsch, D.

    2004-12-01

    Sitting on top of a 3D Y-shaped basin filled mostly with late quaternary deposits, the city of Grenoble (French Alps) is subject to strong amplification of seismic motion (see the SISMOVALP web site). In order to assess the magnitude and 3D complexity of these site effects, we propose a spectral element modeling approach previously applied to the prediction of strong ground motion in the Los Angeles sedimentary basin (Komatitstch et al., 2004). The spectral element method naturally accounts for depth variations of the free surface and of internal interfaces, such as the contact between the sediments and the bedrock. It is also well suited to model the propagation of surface waves generated at the basin edges. The 3D spectral element mesh honors the stiff surface topography of the mountains surrounding the city, as well as the bedrock depth obtained from extensive gravimetric measurements. In the basin, we use a generic 1D velocity model derived from geophysical measurements performed in a deep borehole that reached the substratum at 550 m depth in 1999. Results and comparison to data are shown in the time and frequency domain for small-size (Mw=2.5 and Mw=3.5) local events recorded in the past years. Then, a Mw=5.5 strike-slip event is simulated on the eastern border of the basin along the Belledonne fault, and the results are compared to those obtained by the method of Empirical Green Functions. References: http://www-lgit.obs.ujf-grenoble.fr/sismovalp/ Simulations of ground motion in the Los Angeles basin based upon the spectral- element method, Dimitri Komatitsch, Qinya Liu, Jeroen Tromp, Peter Süss, Christiane Stidham and John H. Shaw, Bulletin of the Seismological Society of America, vol. 94, p 187-206 (2004).

  20. Our Future and Our Only Hope: A Survey of City Halls Regarding Children and Families. A Research Report of the National League of Cities.

    ERIC Educational Resources Information Center

    Born, Catherine E.

    This report contains an executive summary and is based on a survey of 278 American cities with populations over 50,000, concerns problems facing families and children. The survey focused on pressing needs of children and families as seen by city officials, the prominence of these needs in community life, the involvement of city governments in…

  1. Quantification of large-scale urban mass fluxes of xenobiotics and of the river-groundwater interaction in the city of Halle, Germany

    NASA Astrophysics Data System (ADS)

    Reinstorf, F.; Leschik, S.; Musolff, A.; Osenbrück, K.; Strauch, G.; Möder, M.; Schirmer, M.

    In order to quantify the fluxes of micropollutants like pharmaceuticals including endocrine disruptors, and fragrances in the environment modelling approaches in the area of the city of Halle/Saale, Germany were performed. The investigated micropollutants are Bisphenol A, t-Nonylphenol, Carbamazepine, Galaxolide ® and Tonalide ®. These substances were found ubiquitously in the urban groundwater and surface waters. The assessment of the concentration values of these substances in the urban waters showed no significant changes during the city passage. Therefore, a balance model for the whole city area was set up and the main water-bounded mass fluxes of the substances were estimated. The assessment of the mass fluxes shows increasing values of about 20 up to 400% for nearly all investigated micropollutants during the city passage of the urban waters. An exception is Bisphenol A with a constant mass flux. In order to investigate the surface water-groundwater interaction, a transient hydrodynamic river reach model of the Saale River and a groundwater transport model of the area connected to the reach were created by coupling two well known conventional compartment models for river hydraulic and groundwater transport. The inter-compartmental transport of Carbamazepine initiated through infiltration from the Saale River into the groundwater during a flooding event was simulated . A substance mass flux of 3.29 × 10 5 μg d -1 and a fluid flux of 9.95 × 10 3 m 3 d -1 was calculated.

  2. Hall viscosity

    NASA Astrophysics Data System (ADS)

    Read, Nicholas

    2015-03-01

    Viscosity is a transport coefficient relating to transport of momentum, and usually thought of as the analog of friction that occurs in fluids and solids. More formally, it is the response of the stress to the gradients of the fluid velocity field, or to the rate of change of strain (derivatives of displacement from a reference state). In general, viscosity is described by a fourth-rank tensor. Invoking rotation invariance, it reduces to familiar shear and bulk viscosity parts, which describe dissipation, but it can also contain an antisymmetric part, analogous to the Hall conductivity part of the conductivity tensor. In two dimensions this part is a single number, the Hall viscosity. Symmetry of the system under time reversal (or, in two dimensions, reflections) forces it to vanish. In quantum fluids with a gap in the bulk energy spectrum and which lack both time reversal and reflection symmetries the Hall viscosity can be nonzero even at zero temperature. For integer quantum Hall states, it was first calculated by Avron, Seiler, and Zograf, using a Berry curvature approach, analogous to the Chern number for Hall conductivity. In 2008 this was extended by the present author to fractional quantum Hall states and to BCS states in two dimensions. I found that the general result is given by a simple formula ns / 2 , where n is the particle number density, and s is the ``orbital spin'' per particle. The spin s is also related to the shift S, which enters the relation between particle number and magnetic flux needed to put the ground state on a surface of non-trivial topology with introducing defect excitations, by S = 2 s ; the connection was made by Wen and Zee. The values of s and S are rational numbers, and are robust--unchanged under perturbations that do not cause the bulk energy gap to collapse--provided rotation as well as translation symmetry are maintained. Hall viscosity can be measured in principle, though a simple way to do so is lacking. It enters various

  3. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FOURTEENTH FLOOR Y-CORRIDOR, FACING NORTHWEST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  4. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FOURTEENTH FLOOR Y-CORRIDOR, FACING SOUTHWEST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  5. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FOURTEENTH FLOOR Y-CORRIDOR NEAR ROOM 1403, FACING SOUTHWEST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  6. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FIFTH FLOOR Y-CORRIDOR SOUTH SIDE OF ELEVATOR LOBBY, FACING WEST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  7. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FIFTH FLOOR Y-CORRIDOR SOUTH SIDE OF ELEVATOR LOBBY, FACING NORTHEAST. - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  8. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FIFTH FLOOR Y-CORRIDOR NORTH SIDE OF ELEVATOR LOBBY, FACING EAST. - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  9. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL WEST ENTRANCE COURTYARD SHOWING FLOORING, COLUMNS AND BRONZE DOORS, FACING EAST. - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  10. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL WEST ENTRANCE COURTYARD SHOWING BRONZE DOORS AND HANDRAILS, FACING EAST. - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  11. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL WEST ENTRANCE COURTYARD SHOWING BRONZE DOORS, LIGHT FIXTURES AND GRILLS, FACING EAST. - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  12. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL WEST ENTRANCE COURTYARD SOUTH ARCADE SHOWING FLOORING AND WALL MOSAICS, FACING WEST. - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  13. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL WEST ENTRANCE COURTYARD NORTHWEST CORNER SHOWING DAMAGED STONE, FACING NORTHWEST. - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  14. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL FOURTEENTH FLOOR SOUTH OFFICE WING SHOWING TYPICAL DOOR HARDWARE, FACING SOUTH - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  15. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL THIRD FLOOR SHOWING ROTUNDA COLUMN CAPITALS AND LIGHT FIXTURES, FACING SOUTHEAST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  16. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL NINETEENTH FLOOR MAIN OFFICE AREA, FACING NORTHWEST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  17. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL NINETEENTH FLOOR MAIN OFFICE AREA SHOWING DEMOLITION OF WEST WALL, FACING WEST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  18. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FOURTEENTH FLOOR, SERVICE AREA DOOR NEAR ELEVATOR LOBBY, FACING SOUTH - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  19. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FIFTH FLOOR NORTH OFFICE AREA, FACING NORTH - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  20. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL NINETEENTH FLOOR MAIN OFFICE AREA SHOWING BEAM AND COLUMN CONNECTION NEAR SOUTHEAST CORNER, FACING SOUTHEAST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  1. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL NINETEENTH FLOOR MAIN OFFICE AREA SHOWING DEMOLITION OF SOUTH WALL, FACING SOUTH - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  2. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL NINETEENTH FLOOR MAIN OFFICE AREA SHOWING BEAM AND COLUMN CONNECTION NEAR NORTHWEST CORNER, FACING NORTHWEST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  3. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL NINETEENTH FLOOR MAIN OFFICE AREA, FACING NORTHEAST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  4. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FIFTH FLOOR WEST OFFICE AREA THAT WAS ORIGINAL ART COMMISSION ROOMS, FACING NORTHEAST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  5. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FIFTH FLOOR BREAK ROOM OFF OF ORIGINAL ART COMMISSION ROOMS, FACING SOUTHEAST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  6. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FIFTH FLOOR BREAK ROOM OFF OF ORIGINAL ART COMMISSION ROOMS, FACING NORTHEAST - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  7. Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. VIEW OF LOS ANGELES CITY HALL FIFTH FLOOR WEST OFFICE AREA THAT WAS ORIGINAL ART COMMISSION ROOMS, FACING NORTHWEST. - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  8. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL WEST ENTRANCE COURTYARD NORTH ARCADE SHOWING TILE WORK, FACING NORTH. - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  9. Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Monica Griesbach, Photographer August 1997. DETAIL OF LOS ANGELES CITY HALL SECOND FLOOR SHOWING SOUTH LOBBY TILE WORK, FACING NORTHWEST. - Los Angeles City Hall, 200 North Spring Street, Los Angeles, Los Angeles County, CA

  10. A New Definition in Atlanta: Q&A with Beverly Hall

    ERIC Educational Resources Information Center

    Crow, Tracy

    2010-01-01

    Beverly Hall has been superintendent of Atlanta Public Schools since 1999. Before coming to Atlanta, Hall was state district superintendent of Newark Public Schools, deputy chancellor for instruction of New York City Public Schools, superintendent of Community School District 27 in New York City, and a principal in Brooklyn. Hall chairs Harvard…

  11. 19. SECOND FLOOR, CITY COMMISSION CHAMBERS, DETAIL OF ARCH WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. SECOND FLOOR, CITY COMMISSION CHAMBERS, DETAIL OF ARCH WITH MURAL ON RIGHT OF BENCH, SHOWING PIONEERS AND ATLANTIC CITY SEAL - City Hall, Atlantic & Tennessee Avenues, Atlantic City, Atlantic County, NJ

  12. Numerical Benchmark of 3D Ground Motion Simulation in the Alpine valley of Grenoble, France.

    NASA Astrophysics Data System (ADS)

    Tsuno, S.; Chaljub, E.; Cornou, C.; Bard, P.

    2006-12-01

    Thank to the use of sophisticated numerical methods and to the access to increasing computational resources, our predictions of strong ground motion become more and more realistic and need to be carefully compared. We report our effort of benchmarking numerical methods of ground motion simulation in the case of the valley of Grenoble in the French Alps. The Grenoble valley is typical of a moderate seismicity area where strong site effects occur. The benchmark consisted in computing the seismic response of the `Y'-shaped Grenoble valley to (i) two local earthquakes (Ml<=3) for which recordings were avalaible; and (ii) two local hypothetical events (Mw=6) occuring on the so-called Belledonne Border Fault (BBF) [1]. A free-style prediction was also proposed, in which participants were allowed to vary the source and/or the model parameters and were asked to provide the resulting uncertainty in their estimation of ground motion. We received a total of 18 contributions from 14 different groups; 7 of these use 3D methods, among which 3 could handle surface topography, the other half comprises predictions based upon 1D (2 contributions), 2D (4 contributions) and empirical Green's function (EGF) (3 contributions) methods. Maximal frequency analysed ranged between 2.5 Hz for 3D calculations and 40 Hz for EGF predictions. We present a detailed comparison of the different predictions using raw indicators (e.g. peak values of ground velocity and acceleration, Fourier spectra, site over reference spectral ratios, ...) as well as sophisticated misfit criteria based upon previous works [2,3]. We further discuss the variability in estimating the importance of particular effects such as non-linear rheology, or surface topography. References: [1] Thouvenot F. et al., The Belledonne Border Fault: identification of an active seismic strike-slip fault in the western Alps, Geophys. J. Int., 155 (1), p. 174-192, 2003. [2] Anderson J., Quantitative measure of the goodness-of-fit of

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

    ERIC Educational Resources Information Center

    Alto, Teresa

    2012-01-01

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

  14. BLDG 2 INTERIOR SHOWING ARCHES IN HALL BY MAIN ENTRY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    BLDG 2 INTERIOR SHOWING ARCHES IN HALL BY MAIN ENTRY - Naval Magazine Lualualei, Headquarters Branch, Police Station, Kolekole Road & Constitution Street intersection, north side of main quad, Pearl City, Honolulu County, HI

  15. 7. STAIR HALL, WITH OPENINGS, AND WAINSCOTING AND BALUSTRADE WORK, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. STAIR HALL, WITH OPENINGS, AND WAINSCOTING AND BALUSTRADE WORK, SECOND FLOOR - Fort Totten, Captain & First Lieutenant's Quarters, Building No. 4, 12 miles southwest of Devils Lake City off Route 57, Devils Lake, Ramsey County, ND

  16. Validation of the 4C code against data from the HELIOS loop at CEA Grenoble

    NASA Astrophysics Data System (ADS)

    Zanino, R.; Bonifetto, R.; Casella, F.; Savoldi Richard, L.

    2013-01-01

    We complete the first validation campaign of the Cryogenic Circuit Conductor and Coil (4C) code, focusing on the cryogenic circuit module of 4C, which is based on the component models from the recently developed "Cryogenics" Modelica library. Measured data from the HELIOS facility (HElium Loop for hIgh LOads Smoothing) at CEA Grenoble, France, are used as reference. HELIOS includes a supercritical He loop (cold circulator, pipes equipped with resistive heaters, control and bypass valves, heat exchangers) and a saturated He bath. A repetitive heat pulse test is simulated with 4C. The computed evolution of temperature, pressure and mass flow rate at different circuit locations, both in the loop and in the bath, shows a very good agreement with the measurements.

  17. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.

    PubMed

    Thomae, R; Conradie, J; Fourie, D; Mira, J; Nemulodi, F; Kuechler, D; Toivanen, V

    2016-02-01

    At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented. PMID:26931949

  18. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS

    NASA Astrophysics Data System (ADS)

    Thomae, R.; Conradie, J.; Fourie, D.; Mira, J.; Nemulodi, F.; Kuechler, D.; Toivanen, V.

    2016-02-01

    At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented.

  19. Social change or business as usual at city hall? Examining an urban municipal government's response to neighbourhood-level health inequities.

    PubMed

    Cahuas, Madelaine C; Wakefield, Sarah; Peng, Yun

    2015-05-01

    There is a renewed interest in the potential of municipal governments working collaboratively with local communities to address health inequities. A growing body of literature has also highlighted the benefits and limitations of participatory approaches in neighbourhood interventions initiated by municipal governments. However, few studies have investigated how neighbourhood interventions tackling health inequities work in real-time and in context, from the perspectives of Community Developers (CDs) who promote community participation. This study uses a process evaluation approach and semi-structured interviews with CDs to explore the challenges they face in implementing a community development, participatory process in the City of Hamilton's strategy to reduce health inequities - Neighbourhood Action. Findings demonstrate that municipal government can facilitate and suppress community participation in complex ways. CDs serve as significant but conflicted intermediaries as they negotiate and navigate power differentials between city and community actors, while also facing structural challenges. We conclude that community participation is important to bottom-up, resident-led social change, and that CDs are central to this work. PMID:25245453

  20. 18. SECOND FLOOR, CITY COMMISSION CHAMBERS, DETAIL OF ARCH WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. SECOND FLOOR, CITY COMMISSION CHAMBERS, DETAIL OF ARCH WITH MURAL ON LEFT OF BENCH, SHOWING SEAMEN,SCIENTIST,SPORTSMEN AND STATE SEAL - City Hall, Atlantic & Tennessee Avenues, Atlantic City, Atlantic County, NJ

  1. The 400W at 1.8K Test Facility at CEA-Grenoble

    NASA Astrophysics Data System (ADS)

    Roussel, P.; Girard, A.; Jager, B.; Rousset, B.; Bonnay, P.; Millet, F.; Gully, P.

    2006-04-01

    A new test facility with a cooling capacity respectively of 400W at 1.8K or 800W at 4.5K, is now under nominal operation in SBT (Low Temperature Department) at CEA Grenoble. It has been recently used for thermohydraulic studies of two phase superfluid helium in autumn 2004. In the near future, this test bench will allow: - to test industrial components at 1.8K (magnets, cavities of accelerators) - to continue the present studies on thermohydraulics of two phase superfluid helium - to develop and simulate new cooling loops for ITER Cryogenics, and other applications such as high Reynolds number flows This new facility consists of a cold box connected to a warm compressor station (one subatmospheric oil ring pump in series with two screw compressors). The cold box, designed by AIR LIQUIDE, comprises two centrifugal cold compressors, a cold turbine, a wet piston expander, counter flow heat exchangers and two phase separators at 4.5K and 1.8K. The new facility uses a Programmable Logic Controller (PLC) connected to a bus for the measurements. The design is modular and will allow the use of saturated fluid flow (two phase flow at 1.8K or 4.5K) or single phase fluid forced flow. Experimental results and cooling capacity in different operation modes are detailed.

  2. The Grenoble Analysis Toolkit (GreAT)-A statistical analysis framework

    NASA Astrophysics Data System (ADS)

    Putze, A.; Derome, L.

    2014-12-01

    The field of astroparticle physics is currently the focus of prolific scientific activity. In the last decade, this field has undergone significant developments thanks to several experimental results from CREAM, PAMELA, Fermi, and H.E.S.S. Moreover, the next generation of instruments, such as AMS-02 (launched on 16 May 2011) and CTA, will undoubtedly facilitate more sensitive and precise measurements of the cosmic-ray and γ-ray fluxes. To fully exploit the wealth of high precision data generated by these experiments, robust and efficient statistical tools such as Markov Chain Monte Carlo algorithms or evolutionary algorithms, able to handle the complexity of joint parameter spaces and datasets, are necessary for a phenomenological interpretation. The Grenoble Analysis Toolkit (GreAT) is an user-friendly and modular object orientated framework in C++, which samples the user-defined parameter space with a pre- or user-defined algorithm. The functionality of GreAT is presented in the context of cosmic-ray physics, where the boron-to-carbon (B/C) ratio is used to constrain cosmic-ray propagation models.

  3. 5. View of Community Hall, first floor interior, entrance hall ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. View of Community Hall, first floor interior, entrance hall on east side of building, facing southeast. Ticket booth center foreground, stairway to auditorium right foreground. - Community Hall, Rainier Avenue & View Drive, Port Gamble, Kitsap County, WA

  4. Quantum Spin Hall Effect

    SciTech Connect

    Bernevig, B.Andrei; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-01-15

    The quantum Hall liquid is a novel state of matter with profound emergent properties such as fractional charge and statistics. Existence of the quantum Hall effect requires breaking of the time reversal symmetry caused by an external magnetic field. In this work, we predict a quantized spin Hall effect in the absence of any magnetic field, where the intrinsic spin Hall conductance is quantized in units of 2 e/4{pi}. The degenerate quantum Landau levels are created by the spin-orbit coupling in conventional semiconductors in the presence of a strain gradient. This new state of matter has many profound correlated properties described by a topological field theory.

  5. 52. GREAT HALL, LOOKING NORTH THROUGH STAIR HALL TO NORTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    52. GREAT HALL, LOOKING NORTH THROUGH STAIR HALL TO NORTH VESTIBULE DOORS - Smithsonian Institution Building, 1000 Jefferson Drive, between Ninth & Twelfth Streets, Southwest, Washington, District of Columbia, DC

  6. Hall effect in hopping regime

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    A simple description of the Hall effect in the hopping regime of conductivity in semiconductors is presented. Expressions for the Hall coefficient and Hall mobility are derived by considering averaged equilibrium electron transport in a single triangle of localization sites in a magnetic field. Dependence of the Hall coefficient is analyzed in a wide range of temperature and magnetic field values. Our theoretical result is applied to our experimental data on temperature dependence of Hall effect and Hall mobility in ZnO.

  7. Hall of Fame.

    ERIC Educational Resources Information Center

    El Rancho Unified School District, Pico Rivera, CA.

    A Hall of Fame was established by the El Rancho Unified School District (California) to identify and honor graduates of the school district who have graduated more than 15 years ago, who have achieved recognition in their chosen field, and who would bring honor to the school district in its honoring of them. Nominees for the Hall of Fame were…

  8. Pulsed hall thruster system

    NASA Technical Reports Server (NTRS)

    Hruby, Vladimir J. (Inventor); Pote, Bruce M. (Inventor); Gamero-Castano, Manuel (Inventor)

    2004-01-01

    A pulsed Hall thruster system includes a Hall thruster having an electron source, a magnetic circuit, and a discharge chamber; a power processing unit for firing the Hall thruster to generate a discharge; a propellant storage and delivery system for providing propellant to the discharge chamber and a control unit for defining a pulse duration .tau.<0.1d.sup.3.rho./m, where d is the characteristic size of the thruster, .rho. is the propellant density at standard conditions, and m is the propellant mass flow rate for operating either the power processing unit to provide to the Hall thruster a power pulse of a pre-selected duration, .tau., or operating the propellant storage and delivery system to provide a propellant flow pulse of duration, .tau., or providing both as pulses, synchronized to arrive coincidentally at the discharge chamber to enable the Hall thruster to produce a discreet output impulse.

  9. The first vineyard concert hall in North America

    NASA Astrophysics Data System (ADS)

    Jaffe, Christopher; Rivera, Carlos

    2002-11-01

    The first vineyard or surround concert hall designed and built in the Western Hemisphere is the Sala Nezahualcoyotl in Mexico City. The Hall was completed in 1976 and is part of the Cultural Center at the Universidad Nacional Autonoma de Mexico. The hall was named after a Toltec poet, architect, and musician who lived in the 15th century and was the Renaissance man of his day. In order to provide the familiar traditional sound of the rectangular (shoebox) European Hall, the acoustic designers set the criteria for reverberation times through the frequency spectrum and the Initial Time Delay Gap at every seat in the house to match the measurements taken at the Grosser Musik vereinssaal in Vienna and Boston Symphony Hall. In this paper we discuss the techniques used to create the traditional sound in a vineyard hall and the reaction of musicians and audiences to the completed facility. The Sala was the model for Suntory Hall in Japan which in turn spawned a number of vineyard halls in Japan. Most recently, the vineyard style seems to be appealing to more and more symphonic organizations in Europe and North America.

  10. Facilty Focus: Residence Halls.

    ERIC Educational Resources Information Center

    Hunnewell, James F., Jr.

    2002-01-01

    Describes the Western Ridge Residence at Colorado College and Beard Hall at Wheaton College. The buildings feature multiple levels that take advantage of views and also help create a "homey" feeling. (EV)

  11. Simmons Hall, Massachusetts.

    ERIC Educational Resources Information Center

    Amelar, Sarah

    2003-01-01

    Describes the design of Simmons Hall, an undergraduate dormitory at the Massachusetts Institute of Technology, including the educational context and design goals. Includes information on the architects, as well as floor plans and photographs. (EV)

  12. Spontaneous Quantum Hall Liquids

    NASA Astrophysics Data System (ADS)

    Zhang, Fan

    2012-02-01

    Driven by electron-electron interactions, bilayer graphene and its thicker cousins, chirally (ABC) stacked multilayers, exhibit a variety of distinct broken symmetry states in which each spin-valley flavor spontaneously transfers charge between layers, because of their flat touching bands and large pseudospin chiralities. These gapped states are accompanied by large momentum space Berry curvatures and different types of topological orders. These competing ground states are distinguished by their flavor Hall conductivities, orbital magnetizations, edge state properties, and response to external fields. These spontaneous quantum Hall (SQH) states at zero field smoothly evolve into quantum Hall ferromagnet states at finite field. Various phase transitions occur by tuning carrier densities, temperature, and external fields. Recently, SQH states have started to be observed and explored in transport and Hall experiments on suspended devices with dual gates.

  13. Synergy between the CIMENT tier-2 HPC centre and the HEP community at LPSC in Grenoble (France)

    NASA Astrophysics Data System (ADS)

    Biscarat, C.; Bzeznik, B.

    2014-06-01

    Two of the most pressing questions in current research in Particle Physics are the characterisation of the newly discovered Higgs-like boson at the LHC and the search for New Phenomena beyond the Standard Model of Particle Physics. Physicists at LPSC in Grenoble are leading the search for one type of New Phenomena in ATLAS. Given the rich multitude of physics studies proceeding in parallel in ATLAS, one limiting factor in the timely analysis of data is the availability of computing resources. Another LPSC team suffers from the same limitation. This team is leading the ultimate precision measurement of the W boson mass with DØ data, which yields an indirect constraint on the Higgs boson mass which can be compared with the direct measurements of the mass of the newly discovered boson at LHC. In this paper, we describe the synergy between CIMENT, a regional multidisciplinary HPC centre, and the HEP community in Grenoble in the context of the analysis of data recorded by the ATLAS experiment at the LHC collider and the D0 experiment at the Tevatron collider. CIMENT is a federation of twelve HPC clusters, of about 90 TFlop/s, one of the most powerful HPC tier-2 centres in France. The sharing of resources between different scientific fields, like the ones discussed in this article, constitutes a great asset because the spikes in need of computing resources are uncorrelated in time between different fields.

  14. [Dietary behavior of the Middle Ages in Grenoble: application of isotopic biogeochemistry of the Saint-Laurent cemetery (XIIIth-XVth centuries, Isère, France)].

    PubMed

    Herrscher, E; Bocherens, H; Valentin, F; Colardelle, R

    2001-05-01

    Isotopic analysis of 13C and 15N of 47 bones from Saint-Laurent de Grenoble cemetery (Grenoble, Isère), from the end of medieval period (XIIIth-XVth centuries AD) allowed to define the food status of animals with regard to the humans and to discuss the variability amongst adults. Adults who died young and those with small stature may have had diets poor in animal protein. The consumption of animal proteins was more important in the XVth than in the XIVth century and could illustrate a typical urban food economy providing its population with a more diversified diet than in rural areas. PMID:11411290

  15. NASA's Hall Thruster Program

    NASA Technical Reports Server (NTRS)

    Jankovsky, Robert S.; Jacobson, David T.; Rawlin, Vincent K.; Mason, Lee S.; Mantenieks, Maris A.; Manzella, David H.; Hofer, Richard R.; Peterson, Peter Y.

    2001-01-01

    NASA's Hall thruster program has base research and focused development efforts in support of the Advanced Space Transportation Program, Space-Based Program, and various other programs. The objective of the base research is to gain an improved understanding of the physical processes and engineering constraints of Hall thrusters to enable development of advanced Hall thruster designs. Specific technical questions that are current priorities of the base effort are: (1) How does thruster life vary with operating point? (2) How can thruster lifetime and wear rate be most efficiently evaluated? (3) What are the practical limitations for discharge voltage as it pertains to high specific impulse operation (high discharge voltage) and high thrust operation (low discharge voltage)? (4) What are the practical limits for extending Hall thrusters to very high input powers? and (5) What can be done during thruster design to reduce cost and integration concerns? The objective of the focused development effort is to develop a 50 kW-class Hall propulsion system, with a milestone of a 50 kW engineering model thruster/system by the end of program year 2006. Specific program wear 2001 efforts, along with the corporate and academic participation, are described.

  16. Nonlocal Anomalous Hall Effect

    NASA Astrophysics Data System (ADS)

    Zhang, Steven S.-L.; Vignale, Giovanni

    2016-04-01

    The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect—the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt /YIG structures.

  17. Conducting Wall Hall Thrusters

    NASA Technical Reports Server (NTRS)

    Goebel, Dan M.; Hofer, Richard R.; Mikellides, Ioannis G.; Katz, Ira; Polk, James E.; Dotson, Brandon

    2013-01-01

    A unique configuration of the magnetic field near the wall of Hall thrusters, called Magnetic Shielding, has recently demonstrated the ability to significantly reduce the erosion of the boron nitride (BN) walls and extend the life of Hall thrusters by orders of magnitude. The ability of magnetic shielding to minimize interactions between the plasma and the discharge chamber walls has for the first time enabled the replacement of insulating walls with conducting materials without loss in thruster performance. The boron nitride rings in the 6 kW H6 Hall thruster were replaced with graphite that self-biased to near the anode potential. The thruster efficiency remained over 60% (within two percent of the baseline BN configuration) with a small decrease in thrust and increase in Isp typical of magnetically shielded Hall thrusters. The graphite wall temperatures decreased significantly compared to both shielded and unshielded BN configurations, leading to the potential for higher power operation. Eliminating ceramic walls makes it simpler and less expensive to fabricate a thruster to survive launch loads, and the graphite discharge chamber radiates more efficiently which increases the power capability of the thruster compared to conventional Hall thruster designs.

  18. High Power Hall Thrusters

    NASA Technical Reports Server (NTRS)

    Jankovsky, Robert; Tverdokhlebov, Sergery; Manzella, David

    1999-01-01

    The development of Hall thrusters with powers ranging from tens of kilowatts to in excess of one hundred kilowatts is considered based on renewed interest in high power. high thrust electric propulsion applications. An approach to develop such thrusters based on previous experience is discussed. It is shown that the previous experimental data taken with thrusters of 10 kW input power and less can be used. Potential mass savings due to the design of high power Hall thrusters are discussed. Both xenon and alternate thruster propellant are considered, as are technological issues that will challenge the design of high power Hall thrusters. Finally, the implications of such a development effort with regard to ground testing and spacecraft intecrati'on issues are discussed.

  19. Extraordinary hall balance

    PubMed Central

    Zhang, S. L.; Liu, Y.; Collins-McIntyre, L. J.; Hesjedal, T.; Zhang, J. Y.; Wang, S. G.; Yu, G. H.

    2013-01-01

    Magnetoresistance (MR) effects are at the heart of modern information technology. However, future progress of giant and tunnelling MR based storage and logic devices is limited by the usable MR ratios of currently about 200% at room-temperature. Colossal MR structures, on the other hand, achieve their high MR ratios of up to 106% only at low temperatures and high magnetic fields. We introduce the extraordinary Hall balance (EHB) and demonstrate room-temperature MR ratios in excess of 31,000%. The new device concept exploits the extraordinary Hall effect in two separated ferromagnetic layers with perpendicular anisotropy in which the Hall voltages can be configured to be carefully balanced or tipped out of balance. Reprogrammable logic and memory is realised using a single EHB element. PACS numbers: 85.75.Nn,85.70.Kh,72.15.Gd,75.60.Ej. PMID:23804036

  20. Model of Hall reconnection.

    PubMed

    Malyshkin, Leonid M

    2008-11-28

    The rate of quasistationary, two-dimensional magnetic reconnection is calculated in the framework of incompressible Hall magnetohydrodynamics, which includes the Hall and electron pressure terms in Ohm's law. The Hall-magnetohydrodynamics equations are solved in a local region across the reconnection electron layer, including only the upstream region and the layer center. In the case when the ion inertial length di is larger than the Sweet-Parker reconnection layer thickness, the dimensionless reconnection rate is found to be independent of the electrical resistivity and equal to di/L, where L is the scale length of the external magnetic field in the upstream region outside the electron layer and the ion layer thickness is found to be di. PMID:19113486

  1. Model of Hall Reconnection

    SciTech Connect

    Malyshkin, Leonid M.

    2008-11-28

    The rate of quasistationary, two-dimensional magnetic reconnection is calculated in the framework of incompressible Hall magnetohydrodynamics, which includes the Hall and electron pressure terms in Ohm's law. The Hall-magnetohydrodynamics equations are solved in a local region across the reconnection electron layer, including only the upstream region and the layer center. In the case when the ion inertial length d{sub i} is larger than the Sweet-Parker reconnection layer thickness, the dimensionless reconnection rate is found to be independent of the electrical resistivity and equal to d{sub i}/L, where L is the scale length of the external magnetic field in the upstream region outside the electron layer and the ion layer thickness is found to be d{sub i}.

  2. First commissioning results with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.

    PubMed

    Thomae, R; Conradie, J; Delsink, H; Du Plessis, H; Fourie, D; Hitz, D; Klopp, M; Kohler, I; Kuechler, D; Lussi, C; McAlister, R; Ntshangase, S; Sakildien, M

    2012-02-01

    iThemba Laboratory for Accelerator Based Science (iThemba LABS) is a multi-disciplinary accelerator facility. One of its main activities is the operation of a separated-sector cyclotron with a K-value of 200, which provides beams of various ion species. These beams are used for fundamental nuclear physics research in the intermediate energy region, radioisotope production, and medical physics applications. Due to the requirements of nuclear physics for new ion species and higher energies, the decision was made to install a copy of the so-called Grenoble test source (GTS) at iThemba LABS. In this paper, we will report on the experimental setup and the first results obtained with the GTS2 at iThemba LABS. PMID:22380170

  3. First commissioning results with the Grenoble test electron cyclotron resonance ion source at iThemba LABSa)

    NASA Astrophysics Data System (ADS)

    Thomae, R.; Conradie, J.; Delsink, H.; Du Plessis, H.; Fourie, D.; Hitz, D.; Klopp, M.; Kohler, I.; Kuechler, D.; Lussi, C.; McAlister, R.; Ntshangase, S.; Sakildien, M.

    2012-02-01

    iThemba Laboratory for Accelerator Based Science (iThemba LABS) is a multi-disciplinary accelerator facility. One of its main activities is the operation of a separated-sector cyclotron with a K-value of 200, which provides beams of various ion species. These beams are used for fundamental nuclear physics research in the intermediate energy region, radioisotope production, and medical physics applications. Due to the requirements of nuclear physics for new ion species and higher energies, the decision was made to install a copy of the so-called Grenoble test source (GTS) at iThemba LABS. In this paper, we will report on the experimental setup and the first results obtained with the GTS2 at iThemba LABS.

  4. First commissioning results with the Grenoble test electron cyclotron resonance ion source at iThemba LABS

    SciTech Connect

    Thomae, R.; Conradie, J.; Delsink, H.; Du Plessis, H.; Fourie, D.; Klopp, M.; Kohler, I.; Lussi, C.; McAlister, R.; Ntshangase, S.; Sakildien, M.; Hitz, D.

    2012-02-15

    iThemba Laboratory for Accelerator Based Science (iThemba LABS) is a multi-disciplinary accelerator facility. One of its main activities is the operation of a separated-sector cyclotron with a K-value of 200, which provides beams of various ion species. These beams are used for fundamental nuclear physics research in the intermediate energy region, radioisotope production, and medical physics applications. Due to the requirements of nuclear physics for new ion species and higher energies, the decision was made to install a copy of the so-called Grenoble test source (GTS) at iThemba LABS. In this paper, we will report on the experimental setup and the first results obtained with the GTS2 at iThemba LABS.

  5. [The value of a child abuse observation clinic. Report of an experience in the area of Grenoble].

    PubMed

    Bost, M; Nalpas, D; Menon, M

    1990-01-01

    In France the epidemiology of child abuse is badly known, because of the lack of connexion between different institutions. We present a child abuse observatory set up in Grenoble in May 1987. The social, educational, judicial and medical department's services are working together. In the first 20 months, 87 cases were recorded: 57 physical abuse, 26 sexual abuse and 5 cases of abuses due to negligence. Precise information was collected concerning the victims, their siblings, the family's risk factor and the offenders, the method by which the information was obtained and the prosecution undertaken. A 10 July 1989 law enforced each Department's governor to set up a service for collecting information about child abuse. Our observatory will serve as a model for this law application. PMID:2175421

  6. Facility 171 Interior view of second floor hall showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Facility 171 - Interior view of second floor hall showing original tile and windows. View facing north - U.S. Naval Base, Pearl Harbor, Latrine Dry Dock No. 2 & Latrine Dry Dock No.3, Near Avenue G adjacent to Dry Dock No. 2 & Dry Dock No. 3, Pearl City, Honolulu County, HI

  7. FACILITY 226, SINGLESTORY DUPLEX, UNIT 327 (UNOCCUPIED), INTERIOR FROM HALL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FACILITY 226, SINGLE-STORY DUPLEX, UNIT 327 (UNOCCUPIED), INTERIOR FROM HALL LOOKING INTO BEDROOMS WITH DIFFERENT WINDOW ARRANGEMENTS. - U.S. Naval Base, Pearl Harbor, Housing Area 1, Single Story Duplex Type, Bounded by Kamehameha Highway, Plantation Drive, South Avenue, Pearl City, Honolulu County, HI

  8. HALL SHOWING DOORWAY TO FOYER (CENTER) WITH ENTRY DOOR IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    HALL SHOWING DOORWAY TO FOYER (CENTER) WITH ENTRY DOOR IN BACKGROUND. VIEW FACING NORTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Three-Bedroom Duplex Type 2, Acacia Road, Birch Circle, and Cedar Drive, Pearl City, Honolulu County, HI

  9. DETAIL OF THE LOCKSET ON THE HALL LINEN CLOSET DOOR. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF THE LOCKSET ON THE HALL LINEN CLOSET DOOR. VIEW FACING SOUTH - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Two-Bedroom Duplex Type 1, Acacia Road, Birch Circle, and Cedar Drive, Pearl City, Honolulu County, HI

  10. FOYER AND HALL TO BEDROOMS. SHOWING THE LINEN CLOSET WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FOYER AND HALL TO BEDROOMS. SHOWING THE LINEN CLOSET WITH BUILT-IN SHELVES AT LEFT. VIEW FACING SOUTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Two-Bedroom Duplex Type 1, Acacia Road, Birch Circle, and Cedar Drive, Pearl City, Honolulu County, HI

  11. MASTER BEDROOM SHOWING THE SLIDING CLOSET DOORS AND THE HALL. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    MASTER BEDROOM SHOWING THE SLIDING CLOSET DOORS AND THE HALL. VIEW FACING SOUTH - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Three-Bedroom Duplex Type 2, Acacia Road, Birch Circle, and Cedar Drive, Pearl City, Honolulu County, HI

  12. LINEN CLOSET IN THE HALL SHOWING THE BUILT IN SHELVES. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LINEN CLOSET IN THE HALL SHOWING THE BUILT IN SHELVES. VIEW FACING SOUTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Three-Bedroom Single-Family Type 7, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

  13. HALL WITH FOYER IN BACKGROUND. NOTE THE TONGUE AND GROOVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    HALL WITH FOYER IN BACKGROUND. NOTE THE TONGUE AND GROOVE WALL BOARDS, CANEC PANEL CEILING AND LINEN CLOSET WITH BUILT-IN SHELVES. VIEW FACING SOUTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, M-Shaped Four-Bedroom Duplex Type 5, Birch Circle, Cedar Drive, Pearl City, Honolulu County, HI

  14. Hall Effect in a Plasma.

    ERIC Educational Resources Information Center

    Kunkel, W. B.

    1981-01-01

    Describes an apparatus and procedure for conducting an undergraduate laboratory experiment to quantitatively study the Hall effect in a plasma. Includes background information on the Hall effect and rationale for conducting the experiment. (JN)

  15. Hall Sweet Home

    ERIC Educational Resources Information Center

    Oguntoyinbo, Lekan

    2011-01-01

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

  16. The Monty Hall Dilemma.

    ERIC Educational Resources Information Center

    Granberg, Donald; Brown, Thad A.

    1995-01-01

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

  17. Modeling the Hall Thruster

    SciTech Connect

    Fisch, N.J.; Fruchtman, A.

    1998-08-01

    The acceleration of the plasma in the Hall thruster to supersonic velocities is examined by the use of a steady state model. Flows that are smooth across the sonic transition plane are found. The possibility of generating flows in which the acceleration across the sonic plane is abrupt, is also studied.

  18. Laurance David Hall.

    PubMed

    Coxon, Bruce

    2011-01-01

    An account is given of the life, scientific contributions, and passing of Laurance David Hall (1938-2009), including his early history and education at the University of Bristol, UK, and the synthesis and NMR spectroscopy of carbohydrates and other natural products during ∼20 years of research and teaching at the University of British Columbia in Vancouver, Canada. Lists of graduate students, post-doctoral fellows, and sabbatical visitors are provided for this period. Following a generous endowment by Dr. Herchel Smith, Professor Hall built a new Department of Medicinal Chemistry at Cambridge University, UK, and greatly expanded his researches into the technology and applications of magnetic resonance imaging (MRI) and zero quantum NMR. MRI technology was applied both to medical problems such as the characterization of cartilage degeneration in knee joints, the measurement of ventricular function, lipid localization in animal models of atherosclerosis, paramagnetic metal complexes of polysaccharides as contrast agents, and studies of many other anatomical features, but also to several aspects of materials analysis, including food analyses, process control, and the elucidation of such physical phenomena as the flow of liquids through porous media, defects in concrete, and the visualization of fungal damage to wood. Professor Hall's many publications, patents, lectures, and honors and awards are described, and also his successful effort to keep the Asilomar facility in Pacific Grove, California as the alternating venue for the annual Experimental NMR Conference. Two memorial services for Professor Hall are remembered. PMID:21763510

  19. Nonlocal anomalous Hall effect

    NASA Astrophysics Data System (ADS)

    Zhang, Shulei; Vignale, Giovanni

    Anomalous Hall effect (AHE) is a distinctive transport property of ferromagnetic metals arising from spin orbit coupling (SOC) in concert with spontaneous spin polarization. Nonetheless, recent experiments have shown that the effect also appears in a nonmagnetic metal in contact with a magnetic insulator. The main puzzle lies in the apparent absence of spin polarized electrons in the non-magnetic metal. Here, we theoretically demonstrate that the scattering of electrons from a rough metal-insulator interface is generally spin-dependent, which results in mutual conversion between spin and charge currents flowing in the plane of the layer. It is the current-carrying spin polarized electrons and the spin Hall effect in the bulk of the metal layer that conspire to generate the AH current. This novel AHE differs from the conventional one only in the spatial separation of the SOC and the magnetization, so we name it as nonlocal AHE. In contrast to other previously proposed mechanisms (e.g., spin Hall AHE and magnetic proximity effect (MPE)), the nonlocal AHE appears on the first order of spin Hall angle and does not rely on the induced moments in the metal layer, which make it experimentally detectable by contrasting the AH current directions of two layered structures such as Pt/Cu/YIG and β -Ta/Cu/YIG (with a thin inserted Cu layer to eliminate the MPE). We predict that the directions of the AH currents in these two trilayers would be opposite since the spin Hall angles of Pt and β -Ta are of opposite signs. Work supported by NSF Grants DMR-1406568.

  20. NASA's 2004 Hall Thruster Program

    NASA Technical Reports Server (NTRS)

    Jacobson, David T.; Manzella, David H.; Hofer, Richard R.; Peterson, Peter Y.

    2004-01-01

    An overview of NASA's Hall thruster research and development tasks conducted during fiscal year 2004 is presented. These tasks focus on: raising the technology readiness level of high power Hall thrusters, developing a moderate-power/ moderate specific impulse Hall thruster, demonstrating high-power/high specific impulse Hall thruster operation, and addressing the fundamental technical challenges of emerging Hall thruster concepts. Programmatic background information, technical accomplishments and out year plans for each program element performed under the sponsorship of the In-Space Transportation Program, Project Prometheus, and the Energetics Project are provided.

  1. Spin Hall effects

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  2. Relativistic Hall effect.

    PubMed

    Bliokh, Konstantin Y; Nori, Franco

    2012-03-23

    We consider the relativistic deformation of quantum waves and mechanical bodies carrying intrinsic angular momentum (AM). When observed in a moving reference frame, the centroid of the object undergoes an AM-dependent transverse shift. This is the relativistic analogue of the spin-Hall effect, which occurs in free space without any external fields. Remarkably, the shifts of the geometric and energy centroids differ by a factor of 2, and both centroids are crucial for the Lorentz transformations of the AM tensor. We examine manifestations of the relativistic Hall effect in quantum vortices and mechanical flywheels and also discuss various fundamental aspects of this phenomenon. The perfect agreement of quantum and relativistic approaches allows applications at strikingly different scales, from elementary spinning particles, through classical light, to rotating black holes. PMID:22540559

  3. Cylindrical geometry hall thruster

    DOEpatents

    Raitses, Yevgeny; Fisch, Nathaniel J.

    2002-01-01

    An apparatus and method for thrusting plasma, utilizing a Hall thruster with a cylindrical geometry, wherein ions are accelerated in substantially the axial direction. The apparatus is suitable for operation at low power. It employs small size thruster components, including a ceramic channel, with the center pole piece of the conventional annular design thruster eliminated or greatly reduced. Efficient operation is accomplished through magnetic fields with a substantial radial component. The propellant gas is ionized at an optimal location in the thruster. A further improvement is accomplished by segmented electrodes, which produce localized voltage drops within the thruster at optimally prescribed locations. The apparatus differs from a conventional Hall thruster, which has an annular geometry, not well suited to scaling to small size, because the small size for an annular design has a great deal of surface area relative to the volume.

  4. Quantum hall ferromagnets

    NASA Astrophysics Data System (ADS)

    Kumar, Akshay

    We study several quantum phases that are related to the quantum Hall effect. Our initial focus is on a pair of quantum Hall ferromagnets where the quantum Hall ordering occurs simultaneously with a spontaneous breaking of an internal symmetry associated with a semiconductor valley index. In our first example ---AlAs heterostructures--- we study domain wall structure, role of random-field disorder and dipole moment physics. Then in the second example ---Si(111)--- we show that symmetry breaking near several integer filling fractions involves a combination of selection by thermal fluctuations known as "order by disorder" and a selection by the energetics of Skyrme lattices induced by moving away from the commensurate fillings, a mechanism we term "order by doping". We also study ground state of such systems near filling factor one in the absence of valley Zeeman energy. We show that even though the lowest energy charged excitations are charge one skyrmions, the lowest energy skyrmion lattice has charge > 1 per unit cell. We then broaden our discussion to include lattice systems having multiple Chern number bands. We find analogs of quantum Hall ferromagnets in the menagerie of fractional Chern insulator phases. Unlike in the AlAs system, here the domain walls come naturally with gapped electronic excitations. We close with a result involving only topology: we show that ABC stacked multilayer graphene placed on boron nitride substrate has flat bands with non-zero local Berry curvature but zero Chern number. This allows access to an interaction dominated system with a non-trivial quantum distance metric but without the extra complication of a non-zero Chern number.

  5. Hall effect magnetometer

    NASA Technical Reports Server (NTRS)

    Woollam, J. A.; Beale, H. A.; Spain, I. L. (Inventor)

    1974-01-01

    A magnetometer which uses a single crystal of bismuth selenide is described. The rhombohedral crystal structure of the sensing element is analyzed. The method of construction of the magnetometer is discussed. It is stated that the sensing crystal has a positive or negative Hall coefficient and a carrier concentration of about 10 to the 18th power to 10 to the 20th power per cubic centimeter.

  6. 27. THIRD FLOOR MAIN HALL FROM SIDE HALL LEADING TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. THIRD FLOOR MAIN HALL FROM SIDE HALL LEADING TO SERVICE STAIRS This hall is lit by three natural sources, the lightwell window of the main stairs visible in the distance, the skylight in the linen closet at the extreme left, and from the glazed openings in the interior and exterior doors of the nurse's room, out of sight to the right. - Woodrow Wilson House, 2340 South S Street, Northwest, Washington, District of Columbia, DC

  7. Impacts of land-use and land-cover changes on rockfall propagation: Insights from the Grenoble conurbation.

    PubMed

    Lopez-Saez, Jérôme; Corona, Christophe; Eckert, Nicolas; Stoffel, Markus; Bourrier, Franck; Berger, Frédéric

    2016-03-15

    Several studies have debated the incidence of global warming on the probability of rock instability, whereas the impacts of land use and land cover (LULC) changes on rockfall propagation and associated hazards have received comparably little interest. In this study we evaluate the impacts of LULC changes on rockfall hazards on the slopes above the village of Crolles (Chartreuse massif, Grenoble conurbation, French Alps) through a three-level approach: (i) diachronic landscape analysis for four different periods of the past (i.e. 1850, 1956, 1975, and 2013), (ii) computation of 3D rockfall simulations taking explicitly account of reconstructed LULC changes, and (iii) resulting changes in rockfall hazards over time. We reveal that the disappearance of viticultural landscapes (relating to the decline of cropping areas during the interwar period) and intense afforestation of the steepest upper portion of the slope resulted in a significant increase of rockfall return period associated to a gradual decrease of mean kinetic energy at the level of the urban front of Crolles. According to the Eurobloc methodology, the degree of hazard decreased significantly despite the continuous and rapid urban sprawl on the slopes. These results underline that forests can indeed have significant protection function but also call for a more systematic inclusion of LULC changes in hazard assessments in the future. PMID:26789372

  8. Magnesium Hall Thruster

    NASA Technical Reports Server (NTRS)

    Szabo, James J.

    2015-01-01

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

  9. Hall Effect Imaging

    PubMed Central

    Shah, Jatin; Balaban, Robert S.

    2010-01-01

    This paper presents a new imaging method based on the classical Hall effect (HE), which describes the origin of a detectable voltage from a conductive object moving in a magnetic field. HE images are formed using ultrasound imaging techniques in a magnetic field. These images reflect the electrical properties of the sample. To demonstrate the feasibility of this method, images of plastic and biological samples are collected. The contrast mechanism and signal-to-noise issues are discussed. Since electrical parameters vary widely among tissue types and pathological states, HE imaging may be a useful tool for biological research and medical diagnosis. PMID:9444846

  10. Genetics Home Reference: Sheldon-Hall syndrome

    MedlinePlus

    ... Genetics Home Health Conditions Sheldon-Hall syndrome Sheldon-Hall syndrome Enable Javascript to view the expand/collapse ... Print All Open All Close All Description Sheldon-Hall syndrome , also known as distal arthrogryposis type 2B, ...

  11. Tomorrow's City.

    ERIC Educational Resources Information Center

    Jones, Emrys

    1979-01-01

    Examines several simple models of cities, discussing possible future changes in city design. The concepts of the megalopolis, linear city, tower block, imploded or miniaturized city, and dispersed city are described. (CS)

  12. Chapin Hall Center for Children.

    ERIC Educational Resources Information Center

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

    This document consists of two separate publications: (1) "The Power of Knowing", a brief 12-page description of the Chapin Hall Center for Children, and (2) "Projects and Publications", a 67-page list of the center's projects and publications as of Autumn 1997. "The Power of Knowing" describes the Chapin Hall Center for Children at the University…

  13. Predictors of Residence Hall Involvement

    ERIC Educational Resources Information Center

    Arboleda, Ana; Wang, Yongyi; Shelley, Mack C., II; Whalen, Donald F.

    2003-01-01

    Residence hall students' (N = 1,186, 52% male, 90% White, 66% freshmen) involvement in their living community is influenced significantly by precollege student characteristics (gender, ethnicity), classification, attitudes (toward hall director, house cabinet, academic comfort, social environment, group study), and environmental variables (noise,…

  14. Residence Hall Seating That Works.

    ERIC Educational Resources Information Center

    Wiens, Janet

    2003-01-01

    Describes the seating chosen for residence halls at the Massachusetts Institute of Technology and the University of New England. The seating required depends on ergonomics, aesthetics, durability, cost, and code requirements. In addition, residence halls must have a range of seating types to accommodate various uses. (SLD)

  15. NASA's Hall Thruster Program 2002

    NASA Technical Reports Server (NTRS)

    Jankovsky, Robert S.; Jacobson, David T.; Pinero, Luis R.; Manzella, David H.; Hofer, Richard R.; Peterson, Peter Y.

    2002-01-01

    The NASA Hall thruster program currently supports a number of tasks related to high power thruster development for a number of customers including the Energetics Program (formerly called the Space-based Program), the Space Solar Power Program, and the In-space Propulsion Program. In program year 2002, two tasks were central to the NASA Hall thruster program: 1) the development of a laboratory Hall thruster capable of providing high thrust at high power-, and 2) investigations into operation of Hall thrusters at high specific impulse. In addition to these two primary thruster development activities, there are a number of other on-going activities supported by the NASA Hall thruster program. These additional activities are related to issues such as high-power power processor architecture, thruster lifetime, and spacecraft integration.

  16. Improved Hall type thruster

    NASA Astrophysics Data System (ADS)

    Wetch, Joseph R.; See-pok Wong, Britt, Edward J.; McCracken, Kevin J.; Lin, Raymond; Petrosov, Valeri; Koroteev, Anatoli

    1995-01-01

    An improved design of the Hall type stationary plasma thruster has been tested in 1994. The test results are presented. The test measures performance, EMI and beam divergence of two models of thrusters from the Russian Keldysh Scientific-Research Institute of Thermal Processes. The first of these engines, T-100 produces 80 mN thruster with power of 1.35 kWe. The other thruster, T-160 is larger and produces 280 nM thrust with 4.5 kWe. Endurance testing of the T-100 for 2000 hours was completed at NIITP. Post operation wear measurements indicate that the insulator life expectency will exceed the 8000 hour design life objective. Improved efficiencies of 48 to 52% were measured for the T-100 and 58-62% (with elevated tank pressure) for the T-160 at specific impulse Isp of 1600 seconds and 2000 seconds respectively.

  17. Farm Hall: The Play

    NASA Astrophysics Data System (ADS)

    Cassidy, David C.

    2013-03-01

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

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

    SciTech Connect

    Zhang, J. Y.; Yang, G.; Wang, S. G. E-mail: ghyu@mater.ustb.edu.cn; Liu, J. L.; Wang, R. M.; Amsellem, E.; Kohn, A.; Yu, G. H. E-mail: ghyu@mater.ustb.edu.cn

    2015-04-13

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

  19. Multilayer thin film Hall effect device

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N. (Inventor); Sisk, R. Charles (Inventor)

    1994-01-01

    A Hall effect device and a method of obtaining a magnetic field map of a magnetic body with the Hall effect device are presented. The device comprises: (1) a substrate, (2) a first layer having a first Hall coefficient deposited over the substrate, and (3) a second layer having a second Hall coefficient deposited over the first layer, the first and second layers cooperating to create, in the Hall effect device, a third Hall coefficient different from the first and second Hall coefficients. Creation of the third Hall coefficient by cooperation of the first and second layers allows use of materials for the first and second layers that were previously unavailable for Hall effect devices due to their relatively weak Hall coefficient.

  20. Martin Hall Receives Inventors Award

    NASA Technical Reports Server (NTRS)

    1965-01-01

    In this photograph, Marshall Space Flight Center Director, Dr. Wernher von Braun, presents a Co-Inventor's award to MSFC employee Martin Hall of the Mechanical Engineering Laboratory during the NASA Anniversary ceremony.

  1. Anomalous Hall effect

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

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

  2. Automated quantum Hall resistance standard

    SciTech Connect

    Schumacher, B.

    1994-12-31

    For precision quantized Hall resistance measurements quantum Hall effect samples have to be checked according to the CCE-guidelines. To perform these checks an automated measuring system is described, which is able to examine and characterize various samples. With these measurements a calibration of a precision 10 k{Omega} resistance standard is obtained with an uncertainty of better than 5 x 10{sup -8} (1 {sigma}) using a long-scale digital multimeter.

  3. Optimization of Cylindrical Hall Thrusters

    SciTech Connect

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

    2007-07-24

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

  4. Optimization of Cylindrical Hall Thrusters

    SciTech Connect

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

    2007-11-27

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

  5. Not your grandfather's concert hall

    NASA Astrophysics Data System (ADS)

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

    2001-05-01

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

  6. PHOTOCOPY OF EARLY STEREO VIEW OF CARPENTERS' HALL. Date and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PHOTOCOPY OF EARLY STEREO VIEW OF CARPENTERS' HALL. Date and photographer unknown. Original in Carpenters' Hall - Carpenters' Company Hall, 320 Chestnut Street & Carpenters' Court, Philadelphia, Philadelphia County, PA

  7. Rockfall frequency and influence of meteorological factors on a limestone cliff of the urban area of Grenoble.

    NASA Astrophysics Data System (ADS)

    D'Amato, Julie; Hantz, Didier; Baillet, Laurent; Guerin, Antoine; Jaboyedoff, Michel

    2015-04-01

    The spatial temporal frequency of rockfall events helps to quantify diffuse rockfall hazard. The influence of meteorological factors can also be studied in order to better know the failure triggering factors, and to predict dangerous periods of the year. Detection and dating of some hundreds of rockfalls has been carried out for the Saint Eynard cliff, which towers above a residential area of the town of Grenoble (French Alps), and which consists of a thinly bedded limestone cliff. The rockfalls have been detected by a diachronic comparison of digital models of the cliff, obtained from annual terrestrial laser scanning. They have been dated by means of a continuous photographic and seismic survey of the cliff. Meteorological data are given by local temperature and rain stations. These data allowed to study the influence of meteorological factors in the failure process. Six hundreds rockfalls (volume 0.005m3 to 1500m3) have been dated by periods of 2 to 11 weeks. The average frequency of the detected rockfalls for the 18 months of survey is 1.0 rockfall per day. The winter periods (with freeze-thaw cycles) clearly show a higher rockfall frequency, up to 1.9 rockfall per day for the most active winter periods. Summer periods show a lower rockfall frequency, between 0.1 and 0.5 rockfall per day. The frequency is close to 0.5 for periods with more rainfall. 126 rockfalls were dated with a precision of 10 min to several hours. For these rockfalls, the average frequency is 0.010 rockfall/h. The frequency is 0.015 rockfall/h for the freezing days (days with negative minimal temperature), 0.029 rockfall/h for the days without freeze but following a freezing day, 0.011 rockfall/h for the days with a rainfall and 0.002 rockfall/h for the other days. Rainfall and freeze-thaw events have also been determined hourly. A rainfall event begins with the beginning of a rainfall, and ends at the beginning of the next 24 hours period without rain. The 24h period has been chosen

  8. Iodine Hall Thruster

    NASA Technical Reports Server (NTRS)

    Szabo, James

    2015-01-01

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

  9. Simulating City Councils: Increasing Student Awareness and Involvement

    ERIC Educational Resources Information Center

    Rinfret, Sara R.

    2012-01-01

    As state capitals and city halls influence our daily lives, how can students become active participants in the affairs of their communities (Saffell and Basehart 2009)? For students to explore this question and local policy making in general, I developed a city council simulation for a state and local government course. This article describes the…

  10. Hall thruster with grooved walls

    SciTech Connect

    Li Hong; Ning Zhongxi; Yu Daren

    2013-02-28

    Axial-oriented and azimuthal-distributed grooves are formed on channel walls of a Hall thruster after the engine undergoes a long-term operation. Existing studies have demonstrated the relation between the grooves and the near-wall physics, such as sheath and electron near-wall transport. The idea to optimize the thruster performance with such grooves was also proposed. Therefore, this paper is devoted to explore the effects of wall grooves on the discharge characteristics of a Hall thruster. With experimental measurements, the variations on electron conductivity, ionization distribution, and integrated performance are obtained. The involved physical mechanisms are then analyzed and discussed. The findings help to not only better understand the working principle of Hall thruster discharge but also establish a physical fundamental for the subsequent optimization with artificial grooves.

  11. Spin Hall controlled magnonic microwaveguides

    SciTech Connect

    Demidov, V. E.; Urazhdin, S.; Rinkevich, A. B.; Reiss, G.; Demokritov, S. O.

    2014-04-14

    We use space-resolved magneto-optical spectroscopy to study the influence of spin Hall effect on the excitation and propagation of spin waves in microscopic magnonic waveguides. We find that the spin Hall effect not only increases the spin-wave propagation length, but also results in an increased excitation efficiency due to the increase of the dynamic susceptibility in the vicinity of the inductive antenna. We show that the efficiency of the propagation length enhancement is strongly dependant on the type of the excited spin-wave mode and its wavelength.

  12. Finite groups with Hall {pi}-subgroups

    SciTech Connect

    Vedernikov, Victor A

    2012-03-31

    New classes of finite groups with Hall {pi}-subgroups that have the Sylow properties are constructed and studied. The classes of groups C{sub {pi}} and D{sub {pi}} introduced by P. Hall are substantially extended. Necessary and sufficient conditions are established under which a finite group has Hall {pi}-subgroups. D-Theorems generalizing D-theorems of P. Hall, Wielandt, Baer, and Hartley are obtained. Bibliography: 30 titles.

  13. A Gift for Reading Hall No. 1

    ERIC Educational Resources Information Center

    MacWilliams, Bryon

    2009-01-01

    In this article, the author describes Reading Hall No. 1 of the Russian State Library. He was placed in the first reading hall in the mid-1990s, when the Russian government still honored Soviet traditions of granting certain privileges to certain foreigners. In the first hall, the rules are different. He can request as many books as he wants. He…

  14. The Other Hall Effect: College Board Physics

    ERIC Educational Resources Information Center

    Sheppard, Keith; Gunning, Amanda M.

    2013-01-01

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

  15. Cleaner in Hall of Residence

    ERIC Educational Resources Information Center

    Hotel and Catering Industry Training Board, Wembley (England).

    This syllabus is intended for the use of training personnel in drawing up training programs for cleaners in halls of residence. Its main objective is to produce fully trained cleaners, thereby maintaining and raising standards. The syllabus is divided into three sections: Introduction to Housekeeping Employees, and Tasks Performed by the Majority…

  16. Atlanta's Own "Hall" of Famer

    ERIC Educational Resources Information Center

    Maxwell, Lesil A.

    2008-01-01

    This article features Beverly L. Hall, poised to become one of the longest-serving superintendents of the Atlanta schools. When she came to Atlanta in 1999, student achievement was sliding downward, teacher morale was dismal, and enrollment was falling as parents pulled their children out of the school system. Under the superintendent's driving…

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-19

    ... Energy Regulatory Commission Gary E. Hall and Rita C. Hall; Notice of Application Accepted for Filing.... Applicant: Gary E. Hall and Rita C. Hall. e. Name of Project: Potter Creek Hydroelectric Project. f...: Mr. Gary E. Hall and Ms. Rita C. Hall, P.O. Box 133, Olney, MT 59927, (406) 881-2345. i. FERC...

  18. One-year study of polycyclic aromatic compounds at an urban site in Grenoble (France): Seasonal variations, gas/particle partitioning and cancer risk estimation.

    PubMed

    Tomaz, Sophie; Shahpoury, Pourya; Jaffrezo, Jean-Luc; Lammel, Gerhard; Perraudin, Emilie; Villenave, Eric; Albinet, Alexandre

    2016-09-15

    21 PAHs, 27 oxy-PAHs and 32 nitro-PAHs were measured every third day over a year in both gaseous (G) and particulate PM10 (P) phases in ambient air of Grenoble (France). Mean total concentrations (G+P) of PAHs and oxy-PAHs were in the same range and about 10ngm(-3). Nitro-PAHs were 50 to 100 times less concentrated averaging 100pgm(-3). Polycyclic aromatic compound (PAC) concentrations were 5 to 7 times higher in "cold" period (October to March) than in "warm" period (April to September). Seasonal variations may be explained by higher primary emissions from residential heating, especially biomass burning in "cold" season. Meteorological conditions and influence of the geomorphology around Grenoble, with the formation of thermal inversion layers leading to the stagnation of pollutants, were additional key parameters. Maximum individual PAC concentrations were observed during two PM10 pollution events in December and February-March. Chemical processes and secondary formation of oxy- and nitro-PAH were probably enhanced by the accumulation of the pollutants during these events. PAC gas/particle partitioning depended on compound molecular weight and vapour pressure. Gas/particle partitioning of oxy- and nitro-PAHs were evaluated using a multi-phase poly-parameter linear free energy relationship model. The PAC cancer risk was assessed using toxic equivalency factors available in the literature (19 PAHs, 10 nitro-PAHs and 1 oxy-PAH). Overall, particle-bound PACs contributed about 76% of the cancer risk. While PAHs accounted for most of the total PAC cancer risk, oxy- and nitro-PAHs could account for up to 24%. The risk quantification across substance classes is limited by toxicological data availability. PMID:27261422

  19. Education Cities

    ERIC Educational Resources Information Center

    Shaked, Haim

    2014-01-01

    In recent years, several cities in Israel have labeled themselves "Education Cities," concentrating on education as their central theme. Employing qualitative techniques, this article aims to describe, define, and conceptualize this phenomenon as it is being realized in three such cities. Findings show that Education Cities differ from…

  20. Planar Hall effect bridge magnetic field sensors

    SciTech Connect

    Henriksen, A. D.; Dalslet, B. T.; Skieller, D. H.; Lee, K. H.; Okkels, F.; Hansen, M. F.

    2010-07-05

    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 Hall effect bridge sensors.

  1. The Other Hall Effect: College Board Physics

    NASA Astrophysics Data System (ADS)

    Sheppard, Keith; Gunning, Amanda M.

    2013-09-01

    Edwin Herbert Hall (1855-1938), discoverer of the Hall effect, was one of the first winners of the AAPT Oersted Medal for his contributions to the teaching of physics. While Hall's role in establishing laboratory work in high schools is widely acknowledged, his position as chair of the physics section of the Committee on College Entrance Requirements was contentious and his involvement in launching College Board Physics, what we call the "other Hall effect," has largely been overlooked. This article details Hall's role in the development of College Board Physics.

  2. Optical Hall effect-model description: tutorial.

    PubMed

    Schubert, Mathias; Kühne, Philipp; Darakchieva, Vanya; Hofmann, Tino

    2016-08-01

    The optical Hall effect is a physical phenomenon that describes the occurrence of magnetic-field-induced dielectric displacement at optical wavelengths, transverse and longitudinal to the incident electric field, and analogous to the static electrical Hall effect. The electrical Hall effect and certain cases of the optical Hall effect observations can be explained by extensions of the classic Drude model for the transport of electrons in metals. The optical Hall effect is most useful for characterization of electrical properties in semiconductors. Among many advantages, while the optical Hall effect dispenses with the need of electrical contacts, electrical material properties such as effective mass and mobility parameters, including their anisotropy as well as carrier type and density, can be determined from the optical Hall effect. Measurement of the optical Hall effect can be performed within the concept of generalized ellipsometry at an oblique angle of incidence. In this paper, we review and discuss physical model equations, which can be used to calculate the optical Hall effect in single- and multiple-layered structures of semiconductor materials. We define the optical Hall effect dielectric function tensor, demonstrate diagonalization approaches, and show requirements for the optical Hall effect tensor from energy conservation. We discuss both continuum and quantum approaches, and we provide a brief description of the generalized ellipsometry concept, the Mueller matrix calculus, and a 4×4 matrix algebra to calculate data accessible by experiment. In a follow-up paper, we will discuss strategies and approaches for experimental data acquisition and analysis. PMID:27505654

  3. Study of marble deterioration at City Hall, Schenectady, NY

    SciTech Connect

    Cheng, R.J.; Castillo, R.

    1984-01-01

    The effects of air pollution and acid precipitation were investigated as causing the erosion of marble. The research indicated that the marble grains are being structurally weakened by a chemical conversion process of marble to gypsum crystals. The surface zone of chemical activity (2-5 mm) shows the presence of fly ash and iron particles, and points to the possibility of a catalytic mechanism for the conversion of sulfur dioxide to sulfate.

  4. Electron dynamics in Hall thruster

    NASA Astrophysics Data System (ADS)

    Marini, Samuel; Pakter, Renato

    2015-11-01

    Hall thrusters are plasma engines those use an electromagnetic fields combination to confine electrons, generate and accelerate ions. Widely used by aerospace industries those thrusters stand out for its simple geometry, high specific impulse and low demand for electric power. Propulsion generated by those systems is due to acceleration of ions produced in an acceleration channel. The ions are generated by collision of electrons with propellant gas atoms. In this context, we can realize how important is characterizing the electronic dynamics. Using Hamiltonian formalism, we derive the electron motion equation in a simplified electromagnetic fields configuration observed in hall thrusters. We found conditions those must be satisfied by electromagnetic fields to have electronic confinement in acceleration channel. We present configurations of electromagnetic fields those maximize propellant gas ionization and thus make propulsion more efficient. This work was supported by CNPq.

  5. The fluctuation induced Hall effect

    SciTech Connect

    Shen, W.; Prager, S.C.

    1993-02-01

    The fluctuation induced Hall term, [le][approximately][ovr J] [times] [approximately][ovr B][ge], has been measured in the MST reversed field pinch. The term is of interest as a possible source of current self-generation (dynamo). It is found to be non-negligible, but small in that it can account for less than 25% of the dynamo driven current.

  6. The fluctuation induced Hall effect

    SciTech Connect

    Shen, W.; Prager, S.C.

    1993-02-01

    The fluctuation induced Hall term, {le}{approximately}{ovr J} {times} {approximately}{ovr B}{ge}, has been measured in the MST reversed field pinch. The term is of interest as a possible source of current self-generation (dynamo). It is found to be non-negligible, but small in that it can account for less than 25% of the dynamo driven current.

  7. Hyperbolic supersymmetric quantum Hall effect

    SciTech Connect

    Hasebe, Kazuki

    2008-12-15

    Developing a noncompact version of the supersymmetric Hopf map, we formulate the quantum Hall effect on a superhyperboloid. Based on OSp(1|2) group theoretical methods, we first analyze the one-particle Landau problem, and successively explore the many-body problem where the Laughlin wave function, hard-core pseudopotential Hamiltonian, and topological excitations are derived. It is also shown that the fuzzy superhyperboloid emerges at the lowest Landau level.

  8. Ionization oscillations in Hall accelerators

    NASA Astrophysics Data System (ADS)

    Barral, S.; Peradzyński, Z.

    2010-01-01

    The underlying mechanism of low-frequency oscillations in Hall accelerators is investigated theoretically. It is shown that relaxation oscillations arise from a competition between avalanche ionization and the advective transport of the working gas. The model derived recovers the slow progression and fast recession of the ionization front. Analytical approximations of the shape of current pulses and of the oscillation frequency are provided for the case of large amplitude oscillations.

  9. Hall-magnetohydrodynamic small-scale dynamos.

    PubMed

    Gómez, Daniel O; Mininni, Pablo D; Dmitruk, Pablo

    2010-09-01

    Magnetic field generation by dynamo action is often studied within the theoretical framework of magnetohydrodynamics (MHD). However, for sufficiently diffuse media, the Hall effect may become non-negligible. We present results from three-dimensional simulations of the Hall-MHD equations subjected to random nonhelical forcing. We study the role of the Hall effect in the dynamo efficiency for different values of the Hall parameter. For small values of the Hall parameter, the small-scale dynamo is more efficient, displaying faster growth and saturating at larger amplitudes of the magnetic field. For larger values of the Hall parameter, saturation of the magnetic field is reached at smaller amplitudes than in the MHD case. We also study energy transfer rates among spatial scales and show that the Hall effect produces a reduction of the direct energy cascade at scales larger than the Hall scale, therefore leading to smaller energy dissipation rates. Finally, we present results stemming from simulations at large magnetic Prandtl numbers, which is the relevant regime in the hot and diffuse interstellar medium. In the range of magnetic Prandtl numbers considered, the Hall effect moves the peak of the magnetic energy spectrum as well as other relevant magnetic length scales toward the Hall scale. PMID:21230195

  10. A holographic quantum Hall ferromagnet

    NASA Astrophysics Data System (ADS)

    Kristjansen, C.; Pourhasan, R.; Semenoff, G. W.

    2014-02-01

    A detailed numerical study of a recent proposal for exotic states of the D3-probe D5 brane system with charge density and an external magnetic field is presented. The state has a large number of coincident D5 branes blowing up to a D7 brane in the presence of the worldvolume electric and magnetic fields which are necessary to construct the holographic state. Numerical solutions have shown that these states can compete with the the previously known chiral symmetry breaking and maximally symmetric phases of the D3-D5 system. Moreover, at integer filling fractions, they are incompressible with integer quantized Hall conductivities. In the dual superconformal defect field theory, these solutions correspond to states which break the chiral and global flavor symmetries spontaneously. The region of the temperature-density plane where the D7 brane has lower energy than the other known D5 brane solutions is identified. A hypothesis for the structure of states with filling fraction and Hall conductivity greater than one is made and tested by numerical computation. A parallel with the quantum Hall ferromagnetism or magnetic catalysis phenomenon which is observed in graphene is drawn. As well as demonstrating that the phenomenon can exist in a strongly coupled system, this work makes a number of predictions of symmetry breaking patterns and phase transitions for such systems.

  11. Fractional quantum Hall effect revisited

    NASA Astrophysics Data System (ADS)

    Jacak, J.; Łydżba, P.; Jacak, L.

    2015-10-01

    The topology-based explanation of the fractional quantum Hall effect (FQHE) is summarized. The cyclotron braid subgroups crucial for this approach are introduced in order to identify the origin of the Laughlin correlations in 2D (two-dimensional) Hall systems. Flux-tubes and vortices for composite fermions in their standard constructions are explained in terms of cyclotron braids. The derivation of the hierarchy of the FQHE is proposed by mapping onto the integer effect within the topology-based approach. The experimental observations of the FQHE supporting the cyclotron braid picture are reviewed with a special attention paid to recent experiments with a suspended graphene. The triggering role of a carrier mobility for organization of the fractional state in Hall configuration is emphasized. The prerequisites for the FQHE are indicated including topological conditions substantially increasing the previously accepted set of physical necessities. The explanation of numerical studies by exact diagonalizations of the fractional Chern insulator states is formulated in terms of the topology condition applied to the Berry field flux quantization. Some new ideas withz regard to the synthetic fractional states in the optical lattices are also formulated.

  12. Fort Hall air emissions study, Fort Hall Indian Reservation, Fort Hall, Idaho

    SciTech Connect

    Metcalf, S.W.; Sonnenfeld, N.L.; Rolka, D.L.; Kaye, W.E.

    1995-11-01

    The Agency for Toxic Substances and Disease Registry (ATSDR) conducted a cross-sectional health study at the Fort Hall Indian Reservation in Idaho to investigate concerns about the health effects on reservation residents that might be attributed to two phosphate-processing plants located near the reservation`s southern border. In addition to increased particulates, air emissions from these plants included phosphorus pentoxide, cadmium, chromium, fluoride, uranium, and its daughter radionuclides. A total of 515 participants -- 229 from Fort Hall and 286 from a comparison group at the Duck Valley Indian Reservation -- were interviewed in person by trained American Indian interviewers. Approximately 100 residents of each reservation performed pulmonary function tests and provided urine specimens that were analyzed for cadmium, chromium, fluoride, and several renal biomarkers.

  13. Tunneling Anomalous and Spin Hall Effects.

    PubMed

    Matos-Abiague, A; Fabian, J

    2015-07-31

    We predict, theoretically, the existence of the anomalous Hall effect when a tunneling current flows through a tunnel junction in which only one of the electrodes is magnetic. The interfacial spin-orbit coupling present in the barrier region induces a spin-dependent momentum filtering in the directions perpendicular to the tunneling current, resulting in a skew tunneling even in the absence of impurities. This produces an anomalous Hall conductance and spin Hall currents in the nonmagnetic electrode when a bias voltage is applied across the tunneling heterojunction. If the barrier is composed of a noncentrosymmetric material, the anomalous Hall conductance and spin Hall currents become anisotropic with respect to both the magnetization and crystallographic directions, allowing us to separate this interfacial phenomenon from the bulk anomalous and spin Hall contributions. The proposed effect should be useful for proving and quantifying the interfacial spin-orbit fields in metallic and metal-semiconductor systems. PMID:26274432

  14. NASA - 77M prototype hall thruster built under the High Voltage Hall accelerator development project

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA - 77M prototype hall thruster built under the High Voltage Hall accelerator development project funded by the Science Mission Directorate ; potential use is propulsion for deep space science missions

  15. Hall Thruster Technology for NASA Science Missions

    NASA Technical Reports Server (NTRS)

    Manzella, David; Oh, David; Aadland, Randall

    2005-01-01

    The performance of a prototype Hall thruster designed for Discovery-class NASA science mission applications was evaluated at input powers ranging from 0.2 to 2.9 kilowatts. These data were used to construct a throttle profile for a projected Hall thruster system based on this prototype thruster. The suitability of such a Hall thruster system to perform robotic exploration missions was evaluated through the analysis of a near Earth asteroid sample return mission. This analysis demonstrated that a propulsion system based on the prototype Hall thruster offers mission benefits compared to a propulsion system based on an existing ion thruster.

  16. Anomalous Hall effect in localization regime

    NASA Astrophysics Data System (ADS)

    Wu, Lin; Zhu, Kai; Yue, Di; Tian, Yuan; Jin, Xiaofeng

    2016-06-01

    The anomalous Hall effect in the ultrathin film regime is investigated in Fe(001)(1-3 nm) films epitaxial on MgO(001). The logarithmic localization correction to longitudinal resistivity and anomalous Hall resistivity are observed at low temperature. We identify that the coefficient of skew scattering has a reduction from metallic to localized regime, while the contribution of side jump has inconspicuous change except for a small drop below 10 K. Furthermore, we discover that the intrinsic anomalous Hall conductivity decreases with the reduction of thickness below 2 nm. Our results provide unambiguous experimental evidence to clarify the problem of localization correction to the anomalous Hall effect.

  17. Listening to the acoustics in concert halls

    NASA Astrophysics Data System (ADS)

    Beranek, Leo L.; Griesinger, David

    2001-05-01

    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.

  18. 77 FR 23477 - City of Watervliet; Notice of Intent To File License Application, Filing of Pre-Application...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-19

    ... Energy Regulatory Commission City of Watervliet; Notice of Intent To File License Application, Filing of...: Notice of Intent to File License Application and Request to Use the Traditional Licensing Process. b..., General Manager, City of Watervliet, City Hall, Watervliet, NY 12189 (518) 270-3800 x 122. i. FERC...

  19. Temperature Gradient in Hall Thrusters

    SciTech Connect

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

    2003-11-24

    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.

  20. Hall-effect arc protector

    DOEpatents

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

    1997-05-13

    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.

  1. Town Hall with Secretary Moniz

    ScienceCinema

    Energy Secretary Ernest Moniz; Deputy Secretary of Energy Daniel Poneman

    2013-07-25

    In a town hall meeting with Department staff, Energy Secretary Ernest Moniz spoke about his plans for a reorganization of the Energy Department?s management structure. The plans will help better achieve the Department?s key priorities and those of the President, including implementing the President?s Climate Action Plan, ?all of the above? energy strategy and nuclear security agenda. After his remarks, Moniz, joined by Deputy Secretary Dan Poneman, took questions from the audience in the Forrestal Auditorium as well as email questions from other Department locations.

  2. Anodic plasma in Hall thrusters

    SciTech Connect

    Keidar, Michael

    2008-03-01

    In this paper plasma dynamics and ionization of propellant gas are modeled within the anode holes used for gas injection of a Hall thruster. Under conditions of anode coating with dielectric material, the discharge current should close within these holes, which results in ionization and formation of plasma jets emanating from the openings. The model shows that gas ionization inside the anode holes is very significant. For instance, the electron density increases by two orders of magnitude under certain conditions. The potential drop in the anode region which includes the electrostatic sheath inside the hole and potential drop along the hole might be positive or negative, depending on the anode hole radius.

  3. Town Hall with Secretary Moniz

    SciTech Connect

    Energy Secretary Ernest Moniz; Deputy Secretary of Energy Daniel Poneman

    2013-07-18

    In a town hall meeting with Department staff, Energy Secretary Ernest Moniz spoke about his plans for a reorganization of the Energy Department’s management structure. The plans will help better achieve the Department’s key priorities and those of the President, including implementing the President’s Climate Action Plan, “all of the above” energy strategy and nuclear security agenda. After his remarks, Moniz, joined by Deputy Secretary Dan Poneman, took questions from the audience in the Forrestal Auditorium as well as email questions from other Department locations.

  4. Hall-effect arc protector

    DOEpatents

    Rankin, Richard A.; Kotter, Dale K.

    1997-01-01

    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.

  5. Electron Transport in Hall Thrusters

    NASA Astrophysics Data System (ADS)

    McDonald, Michael Sean

    Despite high technological maturity and a long flight heritage, computer models of Hall thrusters remain dependent on empirical inputs and a large part of thruster development to date has been heavily experimental in nature. This empirical approach will become increasingly unsustainable as new high-power thrusters tax existing ground test facilities and more exotic thruster designs stretch and strain the boundaries of existing design experience. The fundamental obstacle preventing predictive modeling of Hall thruster plasma properties and channel erosion is the lack of a first-principles description of electron transport across the strong magnetic fields between the cathode and anode. In spite of an abundance of proposed transport mechanisms, accurate assessments of the magnitude of electron current due to any one mechanism are scarce, and comparative studies of their relative influence on a single thruster platform simply do not exist. Lacking a clear idea of what mechanism(s) are primarily responsible for transport, it is understandably difficult for the electric propulsion scientist to focus his or her theoretical and computational tools on the right targets. This work presents a primarily experimental investigation of collisional and turbulent Hall thruster electron transport mechanisms. High-speed imaging of the thruster discharge channel at tens of thousands of frames per second reveals omnipresent rotating regions of elevated light emission, identified with a rotating spoke instability. This turbulent instability has been shown through construction of an azimuthally segmented anode to drive significant cross-field electron current in the discharge channel, and suggestive evidence points to its spatial extent into the thruster near-field plume as well. Electron trajectory simulations in experimentally measured thruster electromagnetic fields indicate that binary collisional transport mechanisms are not significant in the thruster plume, and experiments

  6. Lactic Acidosis in Diabetic Population: Is Metformin Implicated? Results of a Matched Case-Control Study Performed on the Type 2 Diabetes Population of Grenoble Hospital University

    PubMed Central

    Lepelley, Marion; Giai, Joris; Yahiaoui, Nassima; Chanoine, Sébastien; Villier, Céline

    2016-01-01

    Introduction. To evaluate the strength of association between lactic acidosis (LA) and well-recognized risk factors for LA, particularly the weight of metformin. Methods. This study is a matched case-control analysis concerning the type 2 diabetes population from Grenoble Hospital University. Cases of LA were defined biologically with pH < 7.35 and lactates > 5 mmol/L. They were matched to 2 controls defined as type 2 diabetic inpatients who did not present a LA during the study period. We performed a conditional logistic regression. Results. We included 302 cases and 604 controls; mean age was 69.5 years (SD 11.93). Intercurrent diseases were significantly associated with LA. Chronic medical conditions had a minor impact on LA incidence, except hepatocellular dysfunction. Metformin was significantly associated with a higher LA probability in case of acute kidney injury (AKI) (OR = 1.79; p value = 0.020) but not in patients without AKI. Discussion and Conclusions. According to this study, metformin, compared to acute medical conditions, seemed not to be associated with LA in patients with type 2 diabetes; however in case of AKI, metformin may be associated with LA. PMID:27034959

  7. [The issue of dialysis withdrawal and palliative cares. A 3-year retrospective study carried out at Grenoble university teaching hospital development of a decision-making tool].

    PubMed

    Jarrin, Guillemette; Maurizi-Balzan, Jocelyne; Laval, Guillemette

    2007-07-01

    Dialysis-related constraints encourage questioning about discontinuation of treatment. In France, the 04/22/2005 law, related to patients' rights and end-of-life issues, defines bounds to treatment withdrawal, authorizing it in specific conditions, to avoid foolish obstinacy. Shortly before the publication of this law, a study has been conducted at Grenoble University Teaching Hospital, involving 31 patients followed by the dialysis service and the palliative care service, in order to analyse the circumstances in which withdrawals from dialysis happen. These patients were old and their general condition was very poor. After initiation of the questioning, treatment was removed in older patients and in those who had been dialysed for short time, which suggests they may have poor adaption to the treatment. No dialysis withdrawal was ever decided without the patient consent or without his nearest and dearest consent. After multidisciplinary discussions, a decision-making tool for dialysis withdrawal has been developed, with a view to be a starting point in the thinking process, for each decision to be adapted to each situation. This tool emphasizes the importance of time and collegial consultation in the decision-making process. It points out to that the decision lies with the referent nephrologist. After withdrawing dialysis, palliative cares must be implemented, since stopping the treatment does not mean stopping cares. PMID:17658440

  8. PHOTOCOPY OF EARLY STEREO VIEW OF INTERIOR OF CARPENTERS' HALL. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PHOTOCOPY OF EARLY STEREO VIEW OF INTERIOR OF CARPENTERS' HALL. Date and photographer unknown. Original in Carpenters' Hall - Carpenters' Company Hall, 320 Chestnut Street & Carpenters' Court, Philadelphia, Philadelphia County, PA

  9. Typology for quantum Hall liquids

    NASA Astrophysics Data System (ADS)

    Parameswaran, S. A.; Kivelson, S. A.; Rezayi, E. H.; Simon, S. H.; Sondhi, S. L.; Spivak, B. Z.

    2012-06-01

    There is a close analogy between the response of a quantum Hall liquid (QHL) to a small change in the electron density and the response of a superconductor to an externally applied magnetic flux—an analogy which is made concrete in the Chern-Simons Landau-Ginzburg (CSLG) formulation of the problem. As the types of superconductors are distinguished by this response, so too for QHLs: A typology can be introduced which is, however, richer than that in superconductors owing to the lack of any time-reversal symmetry relating positive and negative fluxes. At the boundary between type I and type II behavior, the CSLG action has a “Bogomol'nyi point,” where the quasiholes (vortices) are noninteracting—at the microscopic level, this corresponds to the behavior of systems governed by a set of model Hamiltonians which have been constructed to render exact a large class of QHL wave functions. All types of QHLs are capable of giving rise to quantized Hall plateaux.

  10. 20th Annual Residence Hall Construction Report

    ERIC Educational Resources Information Center

    Agron, Joe

    2009-01-01

    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 less expensive…

  11. Hall devices improve electric motor efficiency

    NASA Technical Reports Server (NTRS)

    Haeussermann, W.

    1979-01-01

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

  12. 19th Annual Residence Hall Construction Report

    ERIC Educational Resources Information Center

    Agron, Joe

    2008-01-01

    The construction of residence hall facilities at colleges and universities continues to be strong, as institutions scramble to meet the housing needs and varied demands of a growing student population. This article presents data collected from 39 new residence hall projects completed in 2007. According to American School & University's 19th annual…

  13. Training Top 10 Hall of Fame

    ERIC Educational Resources Information Center

    Training, 2012

    2012-01-01

    Microsoft Corporation and SCC Soft Computer are the newest inductees into the Training Top 10 Hall of Fame, joining the ranks of the 11 companies named to the hall since its inception in 2008 (Wyeth Pharmaceuticals subsequently was acquired by Pfizer Inc. in 2009). These 11 companies held Top 10 spots in the Training Top 50, Top 100, and now Top…

  14. Sport for All. Low Cost Sports Halls.

    ERIC Educational Resources Information Center

    Council of Europe, Strasbourg (France).

    This report of the conference on low-cost sports halls, sponsored by the Council of Europe, is divided into two sections: technical studies and conclusions. The introduction to the report provides an overview of the long-term program of the Council of Europe with regard to sport for all and a discussion of multipurpose sports halls. Sociocultural,…

  15. Metal-Film Hall-Effect Devices

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N.

    1994-01-01

    Large positive and negative Hall coefficients achievable. Family of Hall-effect devices made from multilayer metal films instead of semiconductor materials. Metal films easier to fabricate; formed by deposition on variety of substrates, and leads readily attached to them. Fabricated with larger areas, potentially more reliable, and less affected by impurities. Also used to measure magnetic fields. Devices especially useful at low temperatures.

  16. The Scientific Humanism of G. Stanley Hall

    ERIC Educational Resources Information Center

    Meyer, Donald H.

    1971-01-01

    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)

  17. Quantum Hall effect in quantum electrodynamics

    SciTech Connect

    Penin, Alexander A.

    2009-03-15

    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. Survey of Residence Hall Life at NCSU.

    ERIC Educational Resources Information Center

    Dolin, Nancy C.

    A 1977 North Carolina State University survey of a sample of on-campus students determined their attitudes toward residence hall activities, facilities, and staff. Information is shown by sex, class, and residence hall, and totals are weighted to reflect actual proportions in each dorm. Among the findings are the following: cookouts, movies, beer…

  19. View of north front and west sides of hall, facing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of north front and west sides of hall, facing south - International Longshoremen's & Warehousemen's Union Hall, Naval Civil Engineering Laboratory, Port Hueneme Road, Port Hueneme, Ventura County, CA

  20. Interior detail of dispatch boards in main hall, facing west ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior detail of dispatch boards in main hall, facing west - International Longshoremen's & Warehousemen's Union Hall, Naval Civil Engineering Laboratory, Port Hueneme Road, Port Hueneme, Ventura County, CA

  1. Experimental realization of quantized anomalous Hall effect

    NASA Astrophysics Data System (ADS)

    Xue, Qi-Kun

    2014-03-01

    Anomalous Hall effect was discovered by Edwin Hall in 1880. In this talk, we report the experimental observation of the quantized version of AHE, the quantum anomalous Hall effect (QAHE) in thin films of Cr-doped (Bi,Sb)2Te3 magnetic topological insulator. At zero magnetic field, the gate-tuned anomalous Hall resistance exhibits a quantized value of h /e2 accompanied by a significant drop of the longitudinal resistance. The longitudinal resistance vanishes under a strong magnetic field whereas the Hall resistance remains at the quantized value. The realization of QAHE paves a way for developing low-power-consumption electronics. Implications on observing Majorana fermions and other exotic phenomena in magnetic topological insulators will also be discussed. The work was collaborated with Ke He, Yayu Wang, Xucun Ma, Xi Chen, Li Lv, Dai Xi, Zhong Fang and Shoucheng Zhang.

  2. Flexible Hall sensors based on graphene.

    PubMed

    Wang, Zhenxing; Shaygan, Mehrdad; Otto, Martin; Schall, Daniel; Neumaier, Daniel

    2016-04-14

    The excellent electronic and mechanical properties of graphene provide a perfect basis for high performance flexible electronic and sensor devices. Here, we present the fabrication and characterization of flexible graphene based Hall sensors. The Hall sensors are fabricated on 50 μm thick flexible Kapton foil using large scale graphene grown by chemical vapor deposition technique on copper foil. Voltage and current normalized sensitivities of up to 0.096 V VT(-1) and 79 V AT(-1) were measured, respectively. These values are comparable to the sensitivity of rigid silicon based Hall sensors and are the highest values reported so far for any flexible Hall sensor devices. The sensitivity of the Hall sensor shows no degradation after being bent to a minimum radius of 4 mm, which corresponds to a tensile strain of 0.6%, and after 1000 bending cycles to a radius of 5 mm. PMID:26997245

  3. Flexible Hall sensors based on graphene

    NASA Astrophysics Data System (ADS)

    Wang, Zhenxing; Shaygan, Mehrdad; Otto, Martin; Schall, Daniel; Neumaier, Daniel

    2016-03-01

    The excellent electronic and mechanical properties of graphene provide a perfect basis for high performance flexible electronic and sensor devices. Here, we present the fabrication and characterization of flexible graphene based Hall sensors. The Hall sensors are fabricated on 50 μm thick flexible Kapton foil using large scale graphene grown by chemical vapor deposition technique on copper foil. Voltage and current normalized sensitivities of up to 0.096 V VT-1 and 79 V AT-1 were measured, respectively. These values are comparable to the sensitivity of rigid silicon based Hall sensors and are the highest values reported so far for any flexible Hall sensor devices. The sensitivity of the Hall sensor shows no degradation after being bent to a minimum radius of 4 mm, which corresponds to a tensile strain of 0.6%, and after 1000 bending cycles to a radius of 5 mm.

  4. The quantum Hall impedance standard

    NASA Astrophysics Data System (ADS)

    Schurr, J.; Kučera, J.; Pierz, K.; Kibble, B. P.

    2011-02-01

    Alternating current measurements of double-shielded quantum Hall devices have revealed a fascinating property of which only a quantum effect is capable: it can detect its own frequency dependence and convert it to a current dependence which can be used to eliminate both of them. According to an experimentally verified model, the residual frequency dependence is smaller than the measuring uncertainty of 1.3 × 10-9 kHz-1. In this way, a highly precise quantum standard of impedance can be established, without having to correct for any calculated frequency dependence and without the need for any artefact with a calculated frequency dependence. Nothing else like that is known to us and we hope that our results encourage other national metrology institutes to also apply it to impedance metrology and further explore its beautiful properties.

  5. The Stringy Quantum Hall Fluid

    SciTech Connect

    Brodie, John H

    2001-08-20

    Using branes in massive Type IIA string theory, and a novel decoupling limit, we provide an explicit correspondence between non-commutative Chern-Simons theory and the fractional quantum Hall fluid. The role of the electrons is played by D-particles, the background magnetic field corresponds to a RR 2-form flux, and the two-dimensional fluid is described by non-commutative D2-branes. The filling fraction is given by the ratio of the number of D2-branes and the number of D8-branes, and therefore by the ratio rank/level of the Chern-Simons gauge theory. Quasiparticles and quasiholes are realized as endpoints of fundamental strings on the D2-branes, and are found to possess fractional D-particle charges and fractional statistics.

  6. The quantum Hall effect helicity

    SciTech Connect

    Shrivastava, Keshav N.

    2015-04-16

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

  7. Predicting Hall Thruster Operational Lifetime

    NASA Technical Reports Server (NTRS)

    Manzella, David; Yim, John; Boyd, Iain

    2004-01-01

    A simple analytic model predicted Hall thruster channel erosion based on thruster geometry, operating conditions, and magnetic field configuration. This model relied on a one-dimensional representation of the plasma with a fixed ionization fraction and variable ion energies based on the magnetic field distribution. Sputtering was modeled as the result of elastic scattering of ions by neutrals within the channel. Not all scattered ions and neutrals were assumed to reach the channel walls as a result of additional subsequent scattering events. Incorporating this phenomenon resulted in a greater predicted decrease in erosion rate with time than predicted based only on geometric effects. Results from this model were compared to SPT 100 experimental erosion data.

  8. Mexico City

    Atmospheric Science Data Center

    2013-04-18

    ... Mexico City has one of the world's most serious air pollution problems. The city is located atop a high plain at an altitude of ... as the orange and red areas, and mountainous areas appear light blue and green. The position of the clouds within the 70-degree image are ...

  9. City Play.

    ERIC Educational Resources Information Center

    Dargan, Amanda; Zeitlin, Steve

    2000-01-01

    Today, fewer city blocks preserve the confidence of lifestyle and urban geography that sustain traditional games and outdoor play. Large groups of children choosing sides and organizing Red Rover games are no longer commonplace. Teachers must encourage free play; urban planners must build cities that are safe play havens. (MLH)

  10. Observation of spin Hall effective field

    NASA Astrophysics Data System (ADS)

    Fan, Xin; Wu, Jun; Chen, Yunpeng; Jerry, Matthew; Zhang, Huaiwu; Xiao, John

    2013-03-01

    Recent development in spin Hall driven spin transfer torque has attracted intensive interests1. Liu et. al. has shown that the spin transfer torque induced by the spin Hall effect in a normal metal-ferromagnetic metal bilayer can switch the magnetization of the ferromagnetic layer, which may be a potential candidate for magnetic random access memory2. The switching of the magnetization was primarily attributed to the Slonczewski torque3. We show that besides the Slonczewski torque, the spin Hall effect also produces an effective field that can also facilitate the magnetization reversal. This effective field persists even with a Cu spacer layer, and reduces quickly with the increase of the ferromagnetic layer thickness. The observation of the spin Hall effective field shall have ramification on the understanding of both spin transfer torque and spin Hall effect. 1. K. Ando et. al., Electric manipulation of spin relaxation using the spin Hall effect, Physical Review Letters, 101, 036601 (2008). 2. L. Liu et. al., Spin-Torque Switching with the Giant Spin Hall Effect of Tantalum. Science 336, 555-558 (2012). 3. J. Slonczewski, Current-driven excitation of magnetic multilayers. Journal of Magnetism and Magnetic Materials, 159, L1-L7 (1996).

  11. Geometric Hall effects in topological insulator heterostructures

    NASA Astrophysics Data System (ADS)

    Yasuda, K.; Wakatsuki, R.; Morimoto, T.; Yoshimi, R.; Tsukazaki, A.; Takahashi, K. S.; Ezawa, M.; Kawasaki, M.; Nagaosa, N.; Tokura, Y.

    2016-06-01

    Geometry, both in momentum and in real space, plays an important role in the electronic dynamics of condensed matter systems. Among them, the Berry phase associated with nontrivial geometry can be an origin of the transverse motion of electrons, giving rise to various geometric effects such as the anomalous, spin and topological Hall effects. Here, we report two unconventional manifestations of Hall physics: a sign-reversal of the anomalous Hall effect, and the emergence of a topological Hall effect in magnetic/non-magnetic topological insulator heterostructures, Crx(Bi1-ySby)2-xTe3/(Bi1-ySby)2Te3. The sign-reversal in the anomalous Hall effect is driven by a Rashba splitting at the bulk bands, which is caused by the broken spatial inversion symmetry. Instead, the topological Hall effect arises in a wide temperature range below the Curie temperature, in a region where the magnetic-field dependence of the Hall resistance largely deviates from the magnetization. Its origin is assigned to the formation of a Néel-type skyrmion induced by the Dzyaloshinskii-Moriya interaction.

  12. South wing roof from the south looking toward center city ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    South wing roof from the south looking toward center city Philadelphia (note the third-floor monitor on the left and damage to the roof over the central pavillion). - U. S. Naval Asylum, Biddle Hall, Gray's Ferry Avenue, Philadelphia, Philadelphia County, PA

  13. The quantum Hall effects: Philosophical approach

    NASA Astrophysics Data System (ADS)

    Lederer, P.

    2015-05-01

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

  14. Piezo Voltage Controlled Planar Hall Effect Devices

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  15. Chiral Thermoelectrics with Quantum Hall Edge States

    NASA Astrophysics Data System (ADS)

    Sánchez, Rafael; Sothmann, Björn; Jordan, Andrew N.

    2015-04-01

    The thermoelectric properties of a three-terminal quantum Hall conductor are investigated. We identify a contribution to the thermoelectric response that relies on the chirality of the carrier motion rather than on spatial asymmetries. The Onsager matrix becomes maximally asymmetric with configurations where either the Seebeck or the Peltier coefficients are zero while the other one remains finite. Reversing the magnetic field direction exchanges these effects, which originate from the chiral nature of the quantum Hall edge states. The possibility to generate spin-polarized currents in quantum spin Hall samples is discussed.

  16. Joule heating in spin Hall geometry

    NASA Astrophysics Data System (ADS)

    Taniguchi, Tomohiro

    2016-07-01

    The theoretical formula for the entropy production rate in the presence of spin current is derived using the spin-dependent transport equation and thermodynamics. This theory is applicable regardless of the source of the spin current, for example, an electric field, a temperature gradient, or the Hall effect. It reproduces the result in a previous work on the dissipation formula when the relaxation time approximation is applied to the spin relaxation rate. By using the developed theory, it is found that the dissipation in the spin Hall geometry has a contribution proportional to the square of the spin Hall angle.

  17. Direct Drive for Low Power Hall Thrusters

    NASA Technical Reports Server (NTRS)

    Dankanich, John W.

    2005-01-01

    Due to recent studies, NASA has initiated the development of a low power Hall thruster for discovery class missions. The potential advantages of a low power Hall thruster is primarily due to its high efficiency operation at low power and its lower complexity compared to ion engines. Direct drive is another method of reducing the complexity of a Hall thruster system while improving its efficiency. The technical challenges associated with this technology are reported. Additionally, the benefits of this technology are discussed based on parametric studies and mission analysis.

  18. Local structures of homogeneous Hall MHD turbulence

    NASA Astrophysics Data System (ADS)

    Miura, H.; Araki, K.

    2011-12-01

    Local structures of decaying homogeneous and isotropic Hall MHD turbulence are studied by means of direct numerical simulations. Regions of strong vorticity and strong current density in Hall MHD turbulence are compared to those of single-fluid MHD turbulence. An analysis by the use of a low-pass filter reveals that the introduction of the Hall term can modify not only small-scale structures of the current density but also structures of the vorticity field, especially at the scales smaller than the ion skin depth.

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

    PubMed

    Islam, S K Firoz; Benjamin, Colin

    2016-09-23

    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. PMID:27533362

  20. Temperature Dependence of the Hall and Longitudinal Resistances in a Quantum Hall Resistance Standard

    PubMed Central

    Matthews, J.; Cage, M. E.

    2005-01-01

    We present detailed measurements of the temperature dependence of the Hall and longitudinal resistances on a quantum Hall device [(GaAs(7)] which has been used as a resistance standard at NIST. We find a simple power law relationship between the change in Hall resistance and the longitudinal resistance as the temperature is varied between 1.4 K and 36 K. This power law holds over seven orders of magnitude change in the Hall resistance. We fit the temperature dependence above about 4 K to thermal activation, and extract the energy gap and the effective g-factor. PMID:27308175

  1. Barrel Calorimeter for the Hall D Spectrometer

    SciTech Connect

    David Urner

    1998-06-01

    The barrel calorimeter for the hall D spectrometer is discussed for standard pointing geometry and a parallel geometry using Lead Scintillating fibres as active material. A comparison with a CSI spectrometer is shown.

  2. Boundary Effective Action for Quantum Hall States.

    PubMed

    Gromov, Andrey; Jensen, Kristan; Abanov, Alexander G

    2016-03-25

    We consider quantum Hall states on a space with boundary, focusing on the aspects of the edge physics which are completely determined by the symmetries of the problem. There are four distinct terms of Chern-Simons type that appear in the low-energy effective action of the state. Two of these protect gapless edge modes. They describe Hall conductance and, with some provisions, thermal Hall conductance. The remaining two, including the Wen-Zee term, which contributes to the Hall viscosity, do not protect gapless edge modes but are instead related to the local boundary response fixed by symmetries. We highlight some basic features of this response. It follows that the coefficient of the Wen-Zee term can change across an interface without closing a gap or breaking a symmetry. PMID:27058090

  3. Boundary Effective Action for Quantum Hall States

    NASA Astrophysics Data System (ADS)

    Gromov, Andrey; Jensen, Kristan; Abanov, Alexander G.

    2016-03-01

    We consider quantum Hall states on a space with boundary, focusing on the aspects of the edge physics which are completely determined by the symmetries of the problem. There are four distinct terms of Chern-Simons type that appear in the low-energy effective action of the state. Two of these protect gapless edge modes. They describe Hall conductance and, with some provisions, thermal Hall conductance. The remaining two, including the Wen-Zee term, which contributes to the Hall viscosity, do not protect gapless edge modes but are instead related to the local boundary response fixed by symmetries. We highlight some basic features of this response. It follows that the coefficient of the Wen-Zee term can change across an interface without closing a gap or breaking a symmetry.

  4. Hall Opens Doors to Astronaut Heroes

    NASA Video Gallery

    Space shuttle astronauts Bonnie Dunbar, Curt Brown and Eileen Collins joined an elite group of American space heroes as they were inducted into the U.S. Astronaut Hall of Fame on April 20, during a...

  5. Quantum Hall effect in momentum space

    NASA Astrophysics Data System (ADS)

    Ozawa, Tomoki; Price, Hannah M.; Carusotto, Iacopo

    2016-05-01

    We theoretically discuss a momentum-space analog of the quantum Hall effect, which could be observed in topologically nontrivial lattice models subject to an external harmonic trapping potential. In our proposal, the Niu-Thouless-Wu formulation of the quantum Hall effect on a torus is realized in the toroidally shaped Brillouin zone. In this analogy, the position of the trap center in real space controls the magnetic fluxes that are inserted through the holes of the torus in momentum space. We illustrate the momentum-space quantum Hall effect with the noninteracting trapped Harper-Hofstadter model, for which we numerically demonstrate how this effect manifests itself in experimental observables. Extension to the interacting trapped Harper-Hofstadter model is also briefly considered. We finally discuss possible experimental platforms where our proposal for the momentum-space quantum Hall effect could be realized.

  6. Residence Hall Furniture: What's on the Horizon?

    ERIC Educational Resources Information Center

    Wiens, Janet

    2002-01-01

    Describes what leading manufacturers are saying about the future of residence hall furniture design, explaining that fabrics, frames, colors, materials, and other factors are combining to give college officials numerous choices. (EV)

  7. D-Zero Collison Hall Ventilation Measurements

    SciTech Connect

    Rucinski, Russell A.; /Fermilab

    2002-09-05

    This engineering note documents air velocity measurements taken on September 5, 2002 for the D-Zero collision hall. These measurements were done after changes were made to the building dampers, DM-1, DM-2, and DM-14 such that the collision hall would be at a slight positive pressure. Measurements were made by Pete Simon and Mike Sarychev. They systematically took velocity measurements across the duct cross sections. Their raw measurements are included.

  8. Spin-Hall effects in metallic antiferromagnets

    NASA Astrophysics Data System (ADS)

    Zhang, Wei

    Materials possessing new parameters for efficient and tunable spin Hall effects are being explored, among which antiferromagnets have become one of the most promising candidates. Two distinct properties of antiferromagnets are the microscopic spin magnetic moment ordering and the intrinsic anisotropy. Thus the natural question arises whether these two unique features of antiferromagnets can become new degrees of freedom for tuning their spin Hall effects. We performed experimental studies using spin pumping and inverse spin Hall detection on prototypical CuAu-I-type metallic antiferromagnets, PtMn, IrMn, PdMn, and FeMn, in which we observed increasing spin Hall effects for the alloys with heavier elements included. In particular, PtMn shows a large spin Hall effect that is comparable to Pt. We also demonstrated that the spin transfer torques from the antiferromagnets are large enough to excite ferromagnetic resonance of an adjacent ferromagnetic layer. We conclude that the sign and magnitude of the spin Hall effects in these antiferromagnets are determined by the atomic spin-orbit coupling of the heavy elements (e.g. Pt and Ir) as well as the large spin magnetic moments of Mn. In addition, by using epitaxial growth, we investigated the influence of the different crystalline and magnetic orientations on the anisotropic spin Hall effects of these antiferromagnets. Most of the experimental results were further corroborated by first-principles calculations, which determine the intrinsic spin Hall effect contribution and suggest pronounced anisotropies. Thus metallic antiferromagnets may become an active component for manipulating spin dependent transport properties in spintronic concepts. Work at Argonne was supported by the U.S. DOE, OS, Materials Sciences and Engineering Division. Work at Center for Nanoscale Materials was supported by DOE, OS-BES (DE-AC02-06CH11357). Work at Julich was supported by SPP 1538 Programme of the DFG.

  9. 75 FR 22770 - Gary E. Hall and Rita Hall; Notice of Availability of Environmental Assessment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Gary E. Hall and Rita Hall; Notice of Availability of Environmental Assessment April 22, 2010. In accordance with the National Environmental Policy Act of 1969, as amended,...

  10. Charge carrier coherence and Hall effect in organic semiconductors

    PubMed Central

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

    2016-01-01

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

  11. Charge carrier coherence and Hall effect in organic semiconductors

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

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

    PubMed

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

    2016-01-01

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

  13. Theory of Nematic Fractional Quantum Hall States

    NASA Astrophysics Data System (ADS)

    You, Yizhi; Cho, Gil Young; Fradkin, Eduardo

    2014-10-01

    We derive an effective field theory for the isotropic-nematic quantum phase transition of fractional quantum Hall states. We demonstrate that for a system with an isotropic background the low-energy effective theory of the nematic order parameter has z =2 dynamical scaling exponent, due to a Berry phase term of the order parameter, which is related to the nondissipative Hall viscosity. Employing the composite fermion theory with a quadrupolar interaction between electrons, we show that a sufficiently attractive quadrupolar interaction triggers a phase transition from the isotropic fractional quantum Hall fluid into a nematic fractional quantum Hall phase. By investigating the spectrum of collective excitations, we demonstrate that the mass gap of the Girvin-MacDonald-Platzman mode collapses at the isotropic-nematic quantum phase transition. On the other hand, Laughlin quasiparticles and the Kohn collective mode remain gapped at this quantum phase transition, and Kohn's theorem is satisfied. The leading couplings between the nematic order parameter and the gauge fields include a term of the same form as the Wen-Zee term. A disclination of the nematic order parameter carries an unquantized electric charge. We also discuss the relation between nematic degrees of freedom and the geometrical response of the fractional quantum Hall fluid.

  14. Dr. Hall and the work cure.

    PubMed

    Reed, Kathlyn L

    2005-01-01

    Herbert James Hall, MD (1870-1923), was a pioneer in the systematic and organized study of occupation as therapy for persons with nervous and mental disorders that he called the "work cure." He began his work in 1904 during the early years of the Arts and Crafts Movement in the United States. His primary interest was the disorder neurasthenia, a condition with many symptoms including chronic fatigue, stress, and inability to work or perform everyday tasks. The prevailing treatment of the day was absolute bed rest known as the "rest cure." Hall believed that neurasthenia was not caused by overwork but by faulty living habits that could be corrected through an ordered life schedule and selected occupations. He identified several principles of therapy that are still used today including graded activity and energy conservation. Dr. Adolph Meyer credits Hall for organizing the ideas on the therapeutic use of occupation (Meyer, 1922). Hall also provided the name American Occupational Therapy Association for the professional organization and served as the fourth president. For his many contributions to the profession Hall deserves to be recognized as a major contributor to the development and organization of occupational therapy. PMID:23927746

  15. Extrinsic spin Hall effect in graphene

    NASA Astrophysics Data System (ADS)

    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.

  16. Stephen Hall Receives 2012 Walter Sullivan Award for Excellence in Science Journalism-Features: Citation

    NASA Astrophysics Data System (ADS)

    Pearson, Helen

    2013-01-01

    Stephen Hall, a freelance science writer and science-communication teacher, received the Walter Sullivan Award for Excellence in Science Journalism-Features at the AGU Fall Meeting Honors Ceremony, held on 5 December 2012 in San Francisco, Calif. Hall was honored for the article "At Fault?" published 15 September 2011 in Nature. The article examines the legal, personal, and political repercussions from a 2009 earthquake in L'Aquila, Italy for seismologists who had attempted to convey seismic risk assessments to the public. The 6.3 magnitude quake devastated the medieval town and caused more than 300 deaths. Six scientists and one government official were subsequently convicted of manslaughter and sentenced to prison for inadequately assessing and mischaracterizing the risks to city residents, despite the inexact nature of seismic risk assessment. The Sullivan award is for work published with a deadline pressure of more than 1 week.

  17. City 2020+

    NASA Astrophysics Data System (ADS)

    Schneider, C.; Buttstädt, M.; Merbitz, H.; Sachsen, T.; Ketzler, G.; Michael, S.; Klemme, M.; Dott, W.; Selle, K.; Hofmeister, H.

    2010-09-01

    This research initiative CITY 2020+ assesses the risks and opportunities for residents in urban built environments under projected demographic and climate change for the year 2020 and beyond, using the City of Aachen as a case study. CITY 2020+ develops scenarios, options and tools for planning and developing sustainable future city structures. We investigate how urban environment, political structure and residential behavior can best be adapted, with attention to the interactions among structural, political, and sociological configurations and with their consequences on human health. Demographers project that in the EU-25-States by 2050, approximately 30% of the population will be over age 65. Also by 2050, average tem¬peratures are projected to rise by 1 to 2 K. Combined, Europe can expect enhanced thermal stress and higher levels of particulate matter. CITY 2020+ amongst other sub-projects includes research project dealing with (1) a micro-scale assessment of blockages to low-level cold-air drainage flow into the city centre by vegetation and building structures, (2) a detailed analysis of the change of probability density functions related to the occurrence of heat waves during summer and the spatial and temporal structure of the urban heat island (UHI) (3) a meso-scale analysis of particulate matter (PM) concentrations depending on topography, local meteorological conditions and synoptic-scale weather patterns. First results will be presented specifically from sub-projects related to vegetation barriers within cold air drainage, the assessment of the UHI and the temporal and spatial pattern of PM loadings in the city centre. The analysis of the cold air drainage flow is investigated in two consecutive years with a clearing of vegetation stands in the beginning of the second year early in 2010. The spatial pattern of the UHI and its possible enhancement by climate change is addressed employing a unique setup using GPS devices and temperature probes fixed to

  18. Spin Hall Effect in Doped Semiconductor Structures

    NASA Astrophysics Data System (ADS)

    Tse, Wang-Kong; Das Sarma, Sankar

    2006-03-01

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

  19. Spin Hall Effect in Doped Semiconductor Structures

    NASA Astrophysics Data System (ADS)

    Tse, Wang-Kong; Das Sarma, S.

    2006-02-01

    In this Letter we present a microscopic theory of the extrinsic spin Hall effect based on the diagrammatic perturbation theory. Side-jump and skew-scattering contributions are explicitly taken into account to calculate the spin Hall conductivity, and we show that their effects scale as σxySJ/σxySS˜(ℏ/τ)/ɛF, with τ being the transport relaxation time. Motivated by recent experimental work we apply our theory to n- and p-doped 3D and 2D GaAs structures, obtaining σs/σc˜10-3-10-4, where σs(c) is the spin Hall (charge) conductivity, which is in reasonable agreement with the recent experimental results of Kato et al. [Science 306, 1910 (2004)]SCIEAS0036-807510.1126/science.1105514 in n-doped 3D GaAs system.

  20. Moderate Positive Spin Hall Angle in Uranium

    NASA Astrophysics Data System (ADS)

    Anguera, Marta; Singh, Simran; Del Barco, Enrique; Springell, Ross; Miller, Casey W.

    We will present results on FMR and voltage measurements of magnetic damping and the inverse spin Hall effect, respectively, in Ni80Fe20/Uranium bilayers. A pure spin current is injected into an Uranium film from the ferromagnetic resonance dynamics of the magnetization of an adjacent Ni80Fe20 (permalloy) film. The spin current generated is then converted into an electric field by the inverse spin Hall effect. Our results suggest a spin mixing conductance of order 2x1019 m-2 and a positive spin Hall angle of 0.004, which are both unexpected based on trends in d-electron systems. These results support the idea that materials with unfilled f-electron orbitals may require additional exploration for spin physics. Work at UCF was supported by NSF-ECCS grant # 1402990. Work at RIT was supported by NSF-ECCS Grant 1515677.

  1. Piezo Voltage Controlled Planar Hall Effect Devices.

    PubMed

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

    2016-01-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials. PMID:27329068

  2. Logarithmic correlations in quantum Hall plateau transitions

    NASA Astrophysics Data System (ADS)

    Vasseur, Romain

    2015-07-01

    The critical behavior of quantum Hall transitions in two-dimensional disordered electronic systems can be described by a class of complicated, nonunitary conformal field theories with logarithmic correlations. The nature and the physical origin of these logarithmic correlation functions remain, however, mysterious. Using the replica trick and the underlying symmetries of these quantum critical points, we show here how to construct nonperturbatively disorder-averaged observables in terms of Green's functions that scale logarithmically at criticality. In the case of the spin quantum Hall transition, which may occur in disordered superconductors with spin-rotation symmetry and broken time reversal invariance, we argue that our results are compatible with an alternative approach based on supersymmetry. The generalization to the integer quantum Hall plateau transition is also discussed.

  3. Geometric Adiabatic Transport in Quantum Hall States

    NASA Astrophysics Data System (ADS)

    Klevtsov, S.; Wiegmann, P.

    2015-08-01

    We argue that in addition to the Hall conductance and the nondissipative component of the viscous tensor, there exists a third independent transport coefficient, which is precisely quantized. It takes constant values along quantum Hall plateaus. We show that the new coefficient is the Chern number of a vector bundle over moduli space of surfaces of genus 2 or higher and therefore cannot change continuously along the plateau. As such, it does not transpire on a sphere or a torus. In the linear response theory, this coefficient determines intensive forces exerted on electronic fluid by adiabatic deformations of geometry and represents the effect of the gravitational anomaly. We also present the method of computing the transport coefficients for quantum Hall states.

  4. Geometric Adiabatic Transport in Quantum Hall States.

    PubMed

    Klevtsov, S; Wiegmann, P

    2015-08-21

    We argue that in addition to the Hall conductance and the nondissipative component of the viscous tensor, there exists a third independent transport coefficient, which is precisely quantized. It takes constant values along quantum Hall plateaus. We show that the new coefficient is the Chern number of a vector bundle over moduli space of surfaces of genus 2 or higher and therefore cannot change continuously along the plateau. As such, it does not transpire on a sphere or a torus. In the linear response theory, this coefficient determines intensive forces exerted on electronic fluid by adiabatic deformations of geometry and represents the effect of the gravitational anomaly. We also present the method of computing the transport coefficients for quantum Hall states. PMID:26340197

  5. Piezo Voltage Controlled Planar Hall Effect Devices

    PubMed Central

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

    2016-01-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials. PMID:27329068

  6. The Hall effect in ballistic junctions

    NASA Astrophysics Data System (ADS)

    Ford, C. J. B.; Washburn, S.; Büttiker, M.; Knoedler, C. M.; Hong, J. M.

    1990-04-01

    In narrow high-mobility conductors the predominant source of scattering is reflection of carriers off the confining potential. We demonstrate that by changing the geometry of the intersection of the Hall probes with the conductor, the Hall resistance can be quenched, negative or enhanced. More complex junction geometries can lead to one of these phenomena for one field polarity and to another for the other field polarity. At liquid helium temperatures these results can be explained by following trajectories. In the milli-Kelvin range fluctuations are superimposed. At high fields strong resonant depressions of the Hall resistance are found which may be associated with bound states in the region of the cross.

  7. The fractional quantum hall effect (experiment)

    NASA Astrophysics Data System (ADS)

    Stormer, H. L.

    1984-11-01

    Quantization of the Hall resistance ϱ XY in two-dimensional electron systems and simultaneously vanishing resistivity ϱ XX have been observed at fractional filling ν of Landau levels, ν being close to various rational fractions of p/q with exclusively odd denominator. Where resolved, the Hall resistance is quantized to ϱ XY=h/νe 2 to high accuracy. While the normal quantized Hall effect at integer values of ν=i, (i=1,2,3...) reflects the Landau and spin gaps in the single particle density of states of electrons in a magnetic field, this new phenomena is believed to indicate the condensation of the carriers into a novel, highly-correlated electronic state best described as an electron quantum liquid.

  8. City Geology.

    ERIC Educational Resources Information Center

    Markle, Sandra

    1989-01-01

    This article provides information on the evolution of the building material, concrete, and suggests hands-on activities that allow students to experience concrete's qualities, test the heat absorbency of various ground surface materials, discover how an area's geology changes, and search for city fossils. A reproducible activity sheet is included.…

  9. Shielding consideration for the SSCL experimental halls

    SciTech Connect

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

    1994-03-01

    The Superconducting Super Collider which is being designed and built in Waxahachie, Texas consists Of series of proton accelerators, culminating in a 20 Te proton on proton collider. The collider will be in a tunnel which will be 87 km in circumference and. on average about 30 meters underground. The present design calls for two large interaction halls on the east side of the ring. The shielding for these halls is being designed for an interaction rate of 10{sup 9} Hz or 10{sup 16} interactions per year, based on 10{sup 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 {times} 10{sup 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.

  10. Guiding-center hall viscosity and intrinsic dipole moment of fractional quantum Hall states

    NASA Astrophysics Data System (ADS)

    Park, YeJe

    The fractional quantum Hall effect (FQHE) is the archetype of the strongly correlated systems and the topologically ordered phases. Unlike the integer quantum Hall effect (IQHE) which can be explained by single-particle physics, FQHE exhibits many emergent properties that are due to the strong correlation among many electrons. In this Thesis, among those emergent properties of FQHE, we focus on the guiding-center metric, the guiding-center Hall viscosity, the guiding-center spin, the intrinsic electric dipole moment and the orbital entanglement spectrum. Specifically, we show that the discontinuity of guiding-center Hall viscosity (a bulk property) at edges of incompressible quantum Hall fluids is associated with the presence of an intrinsic electric dipole moment on the edge. If there is a gradient of drift velocity due to a non-uniform electric field, the discontinuity in the induced stress is exactly balanced by the electric force on the dipole. We show that the total Hall viscosity has two distinct contributions: a "trivial'' contribution associated with the geometry of the Landau orbits, and a non-trivial contribution associated with guiding-center correlations. We describe a relation between the intrinsic dipole moment and "momentum polarization'', which relates the guiding-center Hall viscosity to the "orbital entanglement spectrum(OES)''. We observe that using the computationally-more-onerous "real-space entanglement spectrum (RES)'' in the momentum polarization calculation just adds the trivial Landau-orbit contribution to the guiding-center part. This shows that all the non-trivial information is completely contained in the OES, which also exposes a fundamental topological quantity gamma = c˜ - nu, the difference between the "chiral stress-energy anomaly'' (or signed conformal anomaly) and the chiral charge anomaly. This quantity characterizes correlated fractional quantum Hall fluids, and vanishes in integer quantum Hall fluids which are uncorrelated.

  11. Inverse spin Hall effect by spin injection

    NASA Astrophysics Data System (ADS)

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

    2007-09-01

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

  12. Prototype dining hall energy efficiency study

    SciTech Connect

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

    1988-06-01

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

  13. Enhanced Performance of Cylindrical Hall Thrusters

    SciTech Connect

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

    2007-05-14

    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. Enhanced performance of cylindrical Hall thrusters

    SciTech Connect

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

    2007-05-28

    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.

  15. [275 years of Halle's drug exporting establishment].

    PubMed

    Kaiser, W

    1984-04-01

    The forwarding of medicaments in Halle stands in the first place in the early history of the pharmaceutic industry. The enterprise established in the years 1708/1709 worked according to economic points of view seeming modern and occupied temporarily a central position in the export business of drugs. It reached its culmination point in the second half of the 18th century. In the 19th century the export business was fused with the still nowadays existing Waisenhaus druggist 's shop in Halle. PMID:6375176

  16. Proton Knock-Out in Hall A

    SciTech Connect

    Kees de Jager

    2002-06-01

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

  17. Quasihole condensates in quantum Hall liquids

    SciTech Connect

    Suorsa, J.; Viefers, S.; Hansson, T. H.

    2011-06-15

    We develop a formalism to describe quasihole condensates in quantum Hall liquids and thereby extend the conformal field theory approach to the full hierarchy of spin-polarized Abelian states and to several classes of non-Abelian hierarchical states. Most previously proposed spin-polarized quantum Hall wave functions appear as special cases. In this paper we explain the physical motivations for the approach, and exemplify it by explicitly constructing the level-two quasihole condensate state at filling fraction 2/3, and the two level-three states at 5/13 and 5/7 which are built from combinations of quasielectron and quasihole condensates.

  18. High-resolution scanning hall probe microscopy

    NASA Astrophysics Data System (ADS)

    Hicks, Clifford; Luan, Lan; Hendrik Bluhm, J.; Moler, Kathryn; Guikema, Janice; Zeldov, Eli; Shtrikman, Hadas

    2006-03-01

    Scanning hall sensors can be used to directly image magnetic fields at surfaces. They offer high resolution, high sensitivity, operability over a broad temperature range, and linearity. We have fabricated hall sensors on GaAs / Al0.35Ga0.65As and GaAs / Al0.3Ga0.7As heterostructures containing 2D electron gases 40, 39 and 140nm beneath the surface. The sensitive areas of our probes range from microns to 85nm on a side. We report on the field sensitivities of probes of various sizes and their spatial resolution in a scanning configuration.

  19. 13. VIEW NORTH; INTERIOR OF COLUMBUS HALL (AUDITORIUM). Naval ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. VIEW NORTH; INTERIOR OF COLUMBUS HALL (AUDITORIUM). - Naval Undersea Warfare Center, Bowditch Hall, 600 feet east of Smith Street & 350 feet south of Columbia Cove, West bank of Thames River, New London, New London County, CT

  20. 14. VIEW SOUTH; INTERIOR OF COLUMBUS HALL FROM STAGE. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. VIEW SOUTH; INTERIOR OF COLUMBUS HALL FROM STAGE. - Naval Undersea Warfare Center, Bowditch Hall, 600 feet east of Smith Street & 350 feet south of Columbia Cove, West bank of Thames River, New London, New London County, CT

  1. 4. MESS HALL, FRONT AND LEFT SIDES, LOOKING SOUTHWEST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. MESS HALL, FRONT AND LEFT SIDES, LOOKING SOUTHWEST. - NIKE Missile Base SL-40, Mess Hall, East central portion of base, southeast of Barracks No. 2, northwest of Administration Building, Hecker, Monroe County, IL

  2. 2. MESS HALL, RIGHT SIDE, LOOKING EAST. NIKE Missile ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. MESS HALL, RIGHT SIDE, LOOKING EAST. - NIKE Missile Base SL-40, Mess Hall, East central portion of base, southeast of Barracks No. 2, northwest of Administration Building, Hecker, Monroe County, IL

  3. 7. PHOTOCOPY, ELEVATION AND SECTION DRAWING OF MESS HALL. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. PHOTOCOPY, ELEVATION AND SECTION DRAWING OF MESS HALL. - NIKE Missile Base SL-40, Mess Hall, East central portion of base, southeast of Barracks No. 2, northwest of Administration Building, Hecker, Monroe County, IL

  4. 3. MESS HALL, REAR SIDE, LOOKING NORTH. NIKE Missile ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. MESS HALL, REAR SIDE, LOOKING NORTH. - NIKE Missile Base SL-40, Mess Hall, East central portion of base, southeast of Barracks No. 2, northwest of Administration Building, Hecker, Monroe County, IL

  5. 6. PHOTOCOPY, PLAN AND SCHEDULE DRAWING OF MESS HALL. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. PHOTOCOPY, PLAN AND SCHEDULE DRAWING OF MESS HALL. - NIKE Missile Base SL-40, Mess Hall, East central portion of base, southeast of Barracks No. 2, northwest of Administration Building, Hecker, Monroe County, IL

  6. 5. MESS HALL, RIGHT AND REAR SIDES, LOOKING NORTHEAST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. MESS HALL, RIGHT AND REAR SIDES, LOOKING NORTHEAST. - NIKE Missile Base SL-40, Mess Hall, East central portion of base, southeast of Barracks No. 2, northwest of Administration Building, Hecker, Monroe County, IL

  7. Contextual view of ILWU Hall, facing northwest with commercial port ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view of ILWU Hall, facing northwest with commercial port buildings visible in the background - International Longshoremen's & Warehousemen's Union Hall, Naval Civil Engineering Laboratory, Port Hueneme Road, Port Hueneme, Ventura County, CA

  8. Interior detail of platform in main hall, with desk, flag, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior detail of platform in main hall, with desk, flag, and banners, facing south - International Longshoremen's & Warehousemen's Union Hall, Naval Civil Engineering Laboratory, Port Hueneme Road, Port Hueneme, Ventura County, CA

  9. Contextual view of ILWU Hall, facing southsouthwest, with ocean bank ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view of ILWU Hall, facing south-southwest, with ocean bank visible in the background - International Longshoremen's & Warehousemen's Union Hall, Naval Civil Engineering Laboratory, Port Hueneme Road, Port Hueneme, Ventura County, CA

  10. 68. TURBINE HALL, LOOKING DOWN FROM THE CONTROL ROOM INTO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    68. TURBINE HALL, LOOKING DOWN FROM THE CONTROL ROOM INTO TURBINE HALL AT UNITS 3, 5, AND 2) - Delaware County Electric Company, Chester Station, Delaware River at South end of Ward Street, Chester, Delaware County, PA

  11. Interior view, groundfloor dining hall extending across the rotunda extension ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view, ground-floor dining hall extending across the rotunda extension from it's northern exterior wall to its southern exterior wall, from the north. - U. S. Naval Asylum, Biddle Hall, Gray's Ferry Avenue, Philadelphia, Philadelphia County, PA

  12. Improved Readout For Micromagnet/Hall-Effect Memories

    NASA Technical Reports Server (NTRS)

    Wu, Jiin-Chuan; Stadler, Henry L.; Katti, Romney R.

    1993-01-01

    Two improved readout circuits for micromagnet/Hall-effect random-access memories designed to eliminate current shunts introducing errors into outputs of older readout circuits. Incorporate additional switching transistors to isolate Hall sensors as needed.

  13. Interior view of central hall from bedroom 2 showing linen ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of central hall from bedroom 2 showing linen dresser, facing southwest. - Albrook Air Force Station, Non-Commissioned Officers' Duplex, East side of Hall Street, Balboa, Former Panama Canal Zone, CZ

  14. 24. BEDROOM #1 INTERIOR SHOWING OPEN DOOR TO HALL WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. BEDROOM #1 INTERIOR SHOWING OPEN DOOR TO HALL WITH HALL LINEN CLOSETS VISIBLE IN BACKGROUND, AND PARTIALLY OPEN DOOR TO CLOSET. VIEW TO EAST. - Big Creek Hydroelectric System, Powerhouse 8, Operator Cottage, Big Creek, Big Creek, Fresno County, CA

  15. The Quantum Anomalous Hall Effect: Theory and Experiment

    NASA Astrophysics Data System (ADS)

    Liu, Chao-Xing; Zhang, Shou-Cheng; Qi, Xiao-Liang

    2016-03-01

    The quantum anomalous Hall effect is defined as a quantized Hall effect realized in a system without an external magnetic field. The quantum anomalous Hall effect is a novel manifestation of topological structure in many-electron systems and may have potential applications in future electronic devices. In recent years, the quantum anomalous Hall effect was proposed theoretically and realized experimentally. In this review article, we provide a systematic overview of the theoretical and experimental developments in this field.

  16. Destruction of the Fractional Quantum Hall Effect by Disorder

    DOE R&D Accomplishments Database

    Laughlin, R. B.

    1985-07-01

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

  17. G. Stanley Hall and the Study of Higher Education.

    ERIC Educational Resources Information Center

    Goodchild, Lester F.

    1996-01-01

    This article reviews the work of G. Stanley Hall, who offered the first course on college and university problems in 1893. It describes Hall's education and academic appointments until 1887, the European origins of his study, the founding of Clark University (Massachusetts) and Hall's presidency, the American beginnings of the field of higher…

  18. Parametric Investigations of Non-Conventional Hall Thruster

    SciTech Connect

    Raitses, Y.; Fisch, N.J.

    2001-01-12

    Hall thrusters might better scale to low power with non-conventional geometry. A 9 cm cylindrical, ceramic-channel, Hall thruster with a cusp-type magnetic field distribution has been investigated. It exhibits discharge characteristics similar to conventional coaxial Hall thrusters, but does not expose as much channel surface. Significantly, its operation is not accompanied by large amplitude discharge low frequency oscillations.

  19. Improved Hall-Effect Sensors For Magnetic Memories

    NASA Technical Reports Server (NTRS)

    Wu, Jiin-Chuan; Stadler, Henry L.; Katti, Romney R.; Chen, Y. C.; Bhattacharya, Pallab K.

    1993-01-01

    High-electron-mobility sensor films deposited on superlattice buffer (strain) layers. Improved Hall-effect sensors offer combination of adequate response and high speed needed for use in micromagnet/Hall-effect random-access memories. Hall-effect material chosen for use in sensors is InAs.

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

    PubMed

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

    2016-01-01

    Electronic states with non-trivial topology host a number of novel phenomena with potential for revolutionizing information technology. The quantum anomalous Hall effect provides spin-polarized dissipation-free transport of electrons, while the quantum spin Hall effect in combination with superconductivity has been proposed as the basis for realizing decoherence-free quantum computing. We introduce a new strategy for realizing these effects, namely by hole and electron doping kagome lattice Mott insulators through, for instance, chemical substitution. As an example, we apply this new approach to the natural mineral herbertsmithite. We prove the feasibility of the proposed modifications by performing ab-initio density functional theory calculations and demonstrate the occurrence of the predicted effects using realistic models. Our results herald a new family of quantum anomalous Hall and quantum spin Hall insulators at affordable energy/temperature scales based on kagome lattices of transition metal ions. PMID:27185665

  1. The magneto-Hall difference and the planar extraordinary Hall balance

    NASA Astrophysics Data System (ADS)

    Zhang, S. L.; Hesjedal, T.

    2016-04-01

    The extraordinary Hall balance (EHB) is a general device concept that harnesses the net extraordinary Hall effect (EHE) arising from two independent magnetic layers, which are electrically in parallel. Different EHB behavior can be achieved by tuning the strength and type of interlayer coupling, i.e., ferromagnetic or antiferromagnetic of varying strength, allowing for logic and memory applications. The physics of the EHE in such a multilayered systems, especially the interface-induced effect, will be discussed. A discrepancy between the magnetization and the Hall effect, called the magneto-Hall difference (MHD) is found, which is not expected in conventional EHE systems. By taking advantage of the MHD effect, and by optimizing the materials structure, magnetoresistance ratios in excess of 40,000% can be achieved at room-temperature. We present a new design, the planar EHB, which has the potential to achieve significantly larger magnetoresistance ratios.

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

    PubMed Central

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

    2016-01-01

    Electronic states with non-trivial topology host a number of novel phenomena with potential for revolutionizing information technology. The quantum anomalous Hall effect provides spin-polarized dissipation-free transport of electrons, while the quantum spin Hall effect in combination with superconductivity has been proposed as the basis for realizing decoherence-free quantum computing. We introduce a new strategy for realizing these effects, namely by hole and electron doping kagome lattice Mott insulators through, for instance, chemical substitution. As an example, we apply this new approach to the natural mineral herbertsmithite. We prove the feasibility of the proposed modifications by performing ab-initio density functional theory calculations and demonstrate the occurrence of the predicted effects using realistic models. Our results herald a new family of quantum anomalous Hall and quantum spin Hall insulators at affordable energy/temperature scales based on kagome lattices of transition metal ions. PMID:27185665

  3. Spin Physics Results from Jefferson Lab Hall B and Hall C

    SciTech Connect

    M. Khandaker

    2004-04-01

    The spin physics program in Jefferson Lab's Hall B and Hall C concentrates on precision studies of the nucleon spin structure functions that can be extracted with inclusive and exclusive polarized scattering experiments in and above the resonance region at low to moderate Q{sup 2}. Results on proton and deuteron spin asymmetries, Lambda{sub 1} (W,Q{sup 2}) and Lambda{sub 2} (W,Q{sup 2}) from the Resonances' Spin Structure--RSS experiment in Hall C and the spin structure function g{sub 1} (x,Q{sup 2}) and its first moment Gamma{sub 1}(Q{sup 2}) from the CLAS EG1 Program in Hall B are presented.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  5. 18th Annual Residence Hall Construction Report

    ERIC Educational Resources Information Center

    Agron, Joe

    2007-01-01

    It is said that "home is where the heart is." Many colleges and universities are keeping that in mind as they continue to invest in building residential facilities to attract students to on-campus living. Residence hall construction at the nation's higher-education institutions remains strong, as the benefits to students, parents, and the college…

  6. A Small Modular Laboratory Hall Effect Thruster

    NASA Astrophysics Data System (ADS)

    Lee, Ty Davis

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

  7. Genetics Home Reference: Pallister-Hall syndrome

    MedlinePlus

    ... in the brain called a hypothalamic hamartoma is characteristic of this disorder. In many cases, these growths do not cause any medical problems; however, some hypothalamic hamartomas lead to seizures or hormone abnormalities that can be life-threatening in infancy. Other features of Pallister-Hall ...

  8. Chapin Hall Projects and Publications. Autumn 1999.

    ERIC Educational Resources Information Center

    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…

  9. Moderate positive spin Hall angle in uranium

    NASA Astrophysics Data System (ADS)

    Singh, Simranjeet; Anguera, Marta; del Barco, Enrique; Springell, Ross; Miller, Casey W.

    2015-12-01

    We report measurements of spin pumping and the inverse spin Hall effect in Ni80Fe20/uranium bilayers designed to study the efficiency of spin-charge interconversion in a super-heavy element. We employ broad-band ferromagnetic resonance on extended films to inject a spin current from the Ni80Fe20 (permalloy) into the uranium layer, which is then converted into an electric field by the inverse spin Hall effect. Surprisingly, our results suggest a spin mixing conductance of order 2 × 1019 m-2 and a positive spin Hall angle of 0.004, which are both merely comparable with those of several transition metals. These results thus support the idea that the electronic configuration may be at least as important as the atomic number in governing spin pumping across interfaces and subsequent spin Hall effects. In fact, given that both the magnitude and the sign are unexpected based on trends in d-electron systems, materials with unfilled f-electron orbitals may hold additional exploration avenues for spin physics.

  10. Moderate positive spin Hall angle in uranium

    SciTech Connect

    Singh, Simranjeet; Anguera, Marta; Barco, Enrique del E-mail: cwmsch@rit.edu; Springell, Ross; Miller, Casey W. E-mail: cwmsch@rit.edu

    2015-12-07

    We report measurements of spin pumping and the inverse spin Hall effect in Ni{sub 80}Fe{sub 20}/uranium bilayers designed to study the efficiency of spin-charge interconversion in a super-heavy element. We employ broad-band ferromagnetic resonance on extended films to inject a spin current from the Ni{sub 80}Fe{sub 20} (permalloy) into the uranium layer, which is then converted into an electric field by the inverse spin Hall effect. Surprisingly, our results suggest a spin mixing conductance of order 2 × 10{sup 19} m{sup −2} and a positive spin Hall angle of 0.004, which are both merely comparable with those of several transition metals. These results thus support the idea that the electronic configuration may be at least as important as the atomic number in governing spin pumping across interfaces and subsequent spin Hall effects. In fact, given that both the magnitude and the sign are unexpected based on trends in d-electron systems, materials with unfilled f-electron orbitals may hold additional exploration avenues for spin physics.

  11. Town Hall on AGU Publishing Practices

    NASA Astrophysics Data System (ADS)

    Forlini, Victoria

    2013-01-01

    Representatives from AGU's leadership and Wiley fielded questions at a town hall during Fall Meeting that ranged from the pricing of AGU's digital library to the fate of AGU books to the role of the governance structure in approving the AGU-Wiley publications partnership.

  12. The Hall D Detector at Jefferson Lab

    SciTech Connect

    Curtis A. Meyer

    2000-12-12

    The Hall D experiment at Jefferson Lab is part of the proposed CEBAF upgrade to 12 GeV beam energy. The Experiment will study gluonic excitations of mesons in the 1.5 to 2.5 GeV/c{sup 2} mass region using an 8 to 9 GeV beam of linearly polarized photons.

  13. Ideal Tearing in the Hall Regime

    NASA Astrophysics Data System (ADS)

    Pucci, F.; Velli, M.; Tenerani, A.

    2015-12-01

    Magnetic reconnection is generally believed to be the mechanism thatexplains explosive events in astrophysical plasmas, such as flares inthe solar corona, substorms. One of the main questions which remainsconcerns how magnetic reconnection may account for the fast magneticenergy conversion to kinetic and thermal energies. Recently it hasbeen shown by Pucci and Velli (2014) that, assuming that currentsheets scales as different powers of the magnetic Reynolds number S,the growth rate of the tearing mode instability in current sheetsincreases as the sheets thin and, once the thickness reaches a scalinga/L ˜ S-1/3, the time scale for the instability to develop becomesof the order of the Alfvén time. In Hall reconnection, dispersivewaves introduced by the Hall effect make the energy release ratesfaster. This effect becomes important to the collisional tearing modeinstability when the thickness of magnetic reversal layer iscomparable to the ion inertia length, where Hall currents produce athree-dimensional quadrupole structure of magnetic field. Here wepresent a linear study aiming to show how an "ideal tearing mode" isachieved when Hall effects are included, including scaling laws forsheet aspect ratios and growth rates.

  14. Soaring Food Prices Squeeze Dining Halls

    ERIC Educational Resources Information Center

    Hermes, JJ

    2008-01-01

    This article reports that students are likely to see a sharp increase in the cost of on-campus meal plans this fall, as rising food prices have sent some college food-service operations into deficits and have forced many to get creative with their fixed budgets. As the cost of food has soared, many dining halls have focused more on reducing…

  15. Hall Viscosity II: Extracting Viscosity from Conductivity

    NASA Astrophysics Data System (ADS)

    Goldstein, Moshe; Bradlyn, Barry; Read, Nicholas

    2012-02-01

    When time reversal symmetry is broken, the viscosity tensor of a fluid can have non-dissipative components, similarly to the non-dissipative off-diagonal Hall conductivity. This ``Hall viscosity'' was recently shown to be half the particle density times the orbital angular momentum per particle. Its observation can thus help elucidate the nature of the more exotic quantum Hall states and related systems (e.g., p+ip superconductors). However, no concrete measurement scheme has hitherto been proposed. Motivated by this question we use linear response theory to derive a general relation between the viscosity tensor and the wave-vector dependent conductivity tensor for a Galilean-invariant quantum fluid. This relation enables one to extract the Hall viscosity, as well as other viscosity coefficients (shear and bulk) when relevant, from electromagnetic response measurements. We also discuss the connection between this result and a similar one recently derived by C. Hoyos and D. T. Son [arXiv:1109.2651].

  16. Residence Hall Furnishings Top 20 List.

    ERIC Educational Resources Information Center

    Tampke, Dale

    1999-01-01

    Provides advice on how to best meet the furniture needs of student residents now and in the future to ensure their privacy and value from the residence hall experience. Twenty tips are highlighted that include considering fire safety, upholstering, lifecycle costs, input from stakeholders, the Americans with Disabilities Act, comfort, lighting,…

  17. Fractional Quantization of the Hall Effect

    DOE R&D Accomplishments Database

    Laughlin, R. B.

    1984-02-27

    The Fractional Quantum Hall Effect is caused by the condensation of a two-dimensional electron gas in a strong magnetic field into a new type of macroscopic ground state, the elementary excitations of which are fermions of charge 1/m, where m is an odd integer. A mathematical description is presented.

  18. FORT HALL SOURCE APPORTIONMENT STUDY (FINAL REPORT)

    EPA Science Inventory

    Air quality monitoring on the Fort Hall Indian Reservation has revealed numerous exceedances of the National Ambient Air Quality Standard (NAAQS) for 24-h averaged PM10 mass. Wind-directional analysis coupled with PM10 measurements have identified the FMC elemental phosphorus p...

  19. June 1992 Hall B collaboration meeting

    SciTech Connect

    Dennis, Lawrence

    1992-06-01

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

  20. 75 FR 433 - Notice of Intent to Repatriate a Cultural Item: Seton Hall University Museum, Seton Hall...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... Hall University, South Orange, NJ AGENCY: National Park Service, Interior. ACTION: Notice. Notice is... University Museum, Seton Hall University, South Orange, NJ, that meets the definitions of ``sacred object... Museum, Seton Hall University, 400 South Orange Ave., South Orange, NJ 07079, telephone (973)...

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

    NASA Astrophysics Data System (ADS)

    Owerre, S. A.

    2016-07-01

    Quite recently, the magnon Hall effect of spin excitations has been observed experimentally on the kagome and pyrochlore lattices. The thermal Hall conductivity κxy changes sign as a function of magnetic field or temperature on the kagome lattice, and κxy changes sign upon reversing the sign of the magnetic field on the pyrochlore lattice. Motivated by these recent exciting experimental observations, we theoretically propose a simple realization of the magnon Hall effect in a two-band model on the honeycomb lattice. The magnon Hall effect of spin excitations arises in the usual way via the breaking of inversion symmetry of the lattice, however, by a next-nearest-neighbour Dzyaloshinsky-Moriya interaction. We find that κxy has a fixed sign for all parameter regimes considered. These results are in contrast to the Lieb, kagome, and pyrochlore lattices. We further show that the low-temperature dependence on the magnon Hall conductivity follows a T2 law, as opposed to the kagome and pyrochlore lattices. These results suggest an experimental procedure to measure thermal Hall conductivity within a class of 2D honeycomb quantum magnets and ultracold atoms trapped in a honeycomb optical lattice.

  2. Long-wavelength corrections to Hall conductivity in fractional quantum Hall fluids

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    Recent work by Hoyos and Son, then Bradlyn et al., has investigated the relation between the long-wavelength (O (q2)) corrections to the Hall conductivity σH (q) and the Hall viscosity of quantum Hall states. These works assume the presence of Galilean and rotational invariance. However, these are not generic symmetries of electrons in condensed matter. We identify translation and (2D) inversion symmetry as the only generic symmetries of an ``ideal'' quantum Hall liquid, as these are needed to guarantee the absence of any dissipationless ground state current density; then σH (q) = σH (- q) characterizes the dissipation less current that flows in response to a spatially-non-uniform electric field. We consider the general problem for fractional quantum Hall (FQH) states without Galilean or rotational invariance, when the guiding-center contribution to the Hall viscosity becomes a non-trivial tensor property related to an emergent geometry of the FQH state, (Bo Yang et,al (PRB 85,165318). Supported by DOE DE-SC0002140 and Agency for Science Technology and Research (A*STAR, Singapore).

  3. Plasma relaxation and topological aspects in Hall magnetohydrodynamics

    SciTech Connect

    Shivamoggi, B. K.

    2012-07-15

    Parker's formulation of isotopological plasma relaxation process in magnetohydrodynamics (MHD) is extended to Hall MHD. The torsion coefficient {alpha} in the Hall MHD Beltrami condition turns out now to be proportional to the potential vorticity. The Hall MHD Beltrami condition becomes equivalent to the potential vorticity conservation equation in two-dimensional (2D) hydrodynamics if the Hall MHD Lagrange multiplier {beta} is taken to be proportional to the potential vorticity as well. The winding pattern of the magnetic field lines in Hall MHD then appears to evolve in the same way as potential vorticity lines in 2D hydrodynamics.

  4. Comparison of Secondary Islands in Collisional Reconnection to Hall Reconnection

    SciTech Connect

    Shepherd, L. S.; Cassak, P. A.

    2010-07-02

    Large-scale resistive Hall-magnetohydrodynamic simulations of the transition from Sweet-Parker (collisional) to Hall (collisionless) magnetic reconnection are presented; the first to separate secondary islands from collisionless effects. Three main results are described. There exists a regime with secondary islands but without collisionless effects, and the reconnection rate is faster than Sweet-Parker, but significantly slower than Hall reconnection. This implies that secondary islands do not cause the fastest reconnection rates. The onset of Hall reconnection ejects secondary islands from the vicinity of the X line, implying that energy is released more rapidly during Hall reconnection. Coronal applications are discussed.

  5. Diagnostics Systems for Permanent Hall Thrusters Development

    NASA Astrophysics Data System (ADS)

    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

  6. Hypernuclear Spectroscopy in JLab's Hall A

    SciTech Connect

    John J. LeRose; A. Acha; P. Bydzovsky; C.C. Chang; E. Cisbani; F. Cusano; C.W. de Jager; R. De Leo; R.J. Feuerbach; S. Frullani; F. Garibaldi; D.W. Higinbotham; M. Iodice; L. Lagamba; P. Markowitz; S. Marrone; B. Reitz; M. Sotona; Miloslav Sotona; G.M. Urciuoli

    2006-10-10

    Results are presented from a new experiment (E94-107) in Hall A of the Thomas Jefferson National Accelerator Facility (JLab) producing Boron-12-lambda using electroproduction, (e,e{prime}K+). In the hypernuclear missing-mass spectrum the experiment achieves very good energy resolution (640 keV FWHM) by exploiting the characteristics of the High Resolution spectrometer pair and the exceptional beam quality available at JLab. The spectrometers were used with the addition an INFN provided pair of septum magnets to reach the desired small angles. Also, the Hall A standard complement of equipment was further augmented by the addition of a Ring Imaging Cherenkov detector (RICH) to achieve the best possible kaon identification.

  7. Induced radioisotopes in a linac treatment hall.

    PubMed

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

    2015-08-01

    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. PMID:25989748

  8. Geometry of fractional quantum Hall fluids

    NASA Astrophysics Data System (ADS)

    Cho, Gil Young; You, Yizhi; Fradkin, Eduardo

    2014-09-01

    We use the field theory description of the fractional quantum Hall states to derive the universal response of these topological fluids to shear deformations and curvature of their background geometry, i.e., the Hall viscosity, and the Wen-Zee term. To account for the coupling to the background geometry, we show that the concept of flux attachment needs to be modified and use it to derive the geometric responses from Chern-Simons theories. We show that the resulting composite particles minimally couple to the spin connection of the geometry. We derive a consistent theory of geometric responses from the Chern-Simons effective field theories and from parton constructions, and apply it to both Abelian and non-Abelian states.

  9. Judy Estes Hall (1940-2015).

    PubMed

    Sammons, Morgan T; Boucher, Andrew

    2016-01-01

    Presents an obituary for Judy Estes Hall, who passed away on November 24, 2015. Hall served as the Executive Officer of the National Register of Health Service Psychologists until her retirement in 2013. She is a recognized expert in the development of education and training standards for the profession of psychology, she also made significant contributions in the field of international psychology, where she was a renowned expert in cross-national credentialing and an advocate for commonality in licensing standards. She was the coauthor of one edited volume and author of more than 60 journal articles, book chapters, and professional publications. A passionate advocate for the advancement of women in psychology, a devoted mother and grandmother, a connoisseur of wine and international traveler extraordinaire, she touched the personal and professional lives of many. (PsycINFO Database Record PMID:27504582

  10. Fractional quantum Hall states of Rydberg polaritons

    NASA Astrophysics Data System (ADS)

    Maghrebi, Mohammad F.; Yao, Norman Y.; Hafezi, Mohammad; Pohl, Thomas; Firstenberg, Ofer; Gorshkov, Alexey V.

    2015-03-01

    We propose a scheme for realizing fractional quantum Hall states of light. In our scheme, photons of two polarizations are coupled to different atomic Rydberg states to form two flavors of Rydberg polaritons that behave as an effective spin. An array of optical cavity modes overlapping with the atomic cloud enables the realization of an effective spin-1 /2 lattice. We show that the dipolar interaction between such polaritons, inherited from the Rydberg states, can be exploited to create a flat, topological band for a single spin-flip excitation. At half filling, this gives rise to a photonic (or polaritonic) fractional Chern insulator—a lattice-based, fractional quantum Hall state of light.

  11. Developments in the quantum Hall effect.

    PubMed

    von Klitzing, Klaus

    2005-09-15

    The most important applications of the quantum Hall effect (QHE) are in the field of metrology. The observed quantization of the resistance is primarily used for the reproduction of the SI unit ohm, but is also important for high precision measurements of both the fine structure constant and the Planck constant. Some current QHE research areas include the analysis of new electron-electron correlation phenomena and the development of a more complete microscopic picture of this quantum effect. Recently, scanning force microscopy (SFM) of the potential distribution in QHE devices has been used to enhance the microscopic understanding of current flow in quantum Hall systems. This confirms the importance of the theoretically predicted stripes of compressible and incompressible electronic states close to the boundary of the QHE devices. PMID:16147506

  12. Hall magnetohydrodynamics: Conservation laws and Lyapunov stability

    NASA Astrophysics Data System (ADS)

    Holm, Darryl D.

    1987-05-01

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

  13. Photoinduced Anomalous Hall Effects in Weyl Semimetals

    NASA Astrophysics Data System (ADS)

    Chan, Ching-Kit; Lee, Patrick A.; Burch, Kenneth S.; Han, Jung Hoon; Ran, Ying

    We examine theoretically the interplay between chiral photons and chiral electrons in Weyl semimetals. Owing to its monopole nature, a three-dimensional Weyl node is topologically-robust against a circularly polarized light. A driven Weyl system exhibits node shifts in the momentum space, in sharp contrast to the gap opening in a driven two-dimensional Dirac system. We show that the node shift leads to a change of the Chern vector which gives arise to a net photoinduced anomalous Hall conductivity, in the plane perpendicular to the light propagation. We shall describe the basic idea behind this generic photoinduced Hall effect, illustrate it with a concrete microscope model, and estimate its feasibility based on current optical experimental techniques.

  14. Fast Camera Imaging of Hall Thruster Ignition

    SciTech Connect

    C.L. Ellison, Y. Raitses and N.J. Fisch

    2011-02-24

    Hall thrusters provide efficient space propulsion by electrostatic acceleration of ions. Rotating electron clouds in the thruster overcome the space charge limitations of other methods. Images of the thruster startup, taken with a fast camera, reveal a bright ionization period which settles into steady state operation over 50 μs. The cathode introduces azimuthal asymmetry, which persists for about 30 μs into the ignition. Plasma thrusters are used on satellites for repositioning, orbit correction and drag compensation. The advantage of plasma thrusters over conventional chemical thrusters is that the exhaust energies are not limited by chemical energy to about an electron volt. For xenon Hall thrusters, the ion exhaust velocity can be 15-20 km/s, compared to 5 km/s for a typical chemical thruster

  15. Spin Hall Magnetoresistance in Metallic Bilayers

    NASA Astrophysics Data System (ADS)

    Kim, Junyeon; Sheng, Peng; Takahashi, Saburo; Mitani, Seiji; Hayashi, Masamitsu

    2016-03-01

    Spin Hall magnetoresistance (SMR) is studied in metallic bilayers that consist of a heavy metal (HM) layer and a ferromagnetic metal (FM) layer. We find a nearly tenfold increase of SMR in W /CoFeB compared to previously studied HM/ferromagnetic insulator systems. The SMR increases with decreasing temperature despite the negligible change in the W layer resistivity. A model is developed to account for the absorption of the longitudinal spin current to the FM layer, one of the key characteristics of a metallic ferromagnet. We find that the model not only quantitatively describes the HM layer thickness dependence of SMR, allowing accurate estimation of the spin Hall angle and the spin diffusion length of the HM layer, but also can account for the temperature dependence of SMR by assuming a temperature dependent spin polarization of the FM layer. These results illustrate the unique role a metallic ferromagnetic layer plays in defining spin transmission across the HM /FM interface.

  16. Anomalous Hall effect in Weyl superconductors

    NASA Astrophysics Data System (ADS)

    Bednik, G.; Zyuzin, A. A.; Burkov, A. A.

    2016-08-01

    We present a theory of the anomalous Hall effect in a topological Weyl superconductor with broken time reversal symmetry. Specifically, we consider a ferromagnetic Weyl metal with two Weyl nodes of opposite chirality near the Fermi energy. In the presence of inversion symmetry, such a metal experiences a weak-coupling Bardeen–Cooper–Schrieffer instability, with pairing of parity-related eigenstates. Due to the nonzero topological charge, carried by the Weyl nodes, such a superconductor is necessarily topologically nontrivial, with Majorana surface states coexisting with the Fermi arcs of the normal Weyl metal. We demonstrate that, surprisingly, the anomalous Hall conductivity of such a superconducting Weyl metal coincides with that of a nonsuperconducting one, under certain conditions, in spite of the nonconservation of charge in a superconductor. We relate this to the existence of an extra (nearly) conserved quantity in a Weyl metal, the chiral charge.

  17. High-resolution scanning hall probe microscopy

    NASA Astrophysics Data System (ADS)

    Hicks, C. W.; Guikema, J. W.; Zeldov, E.

    2005-03-01

    Scanning hall sensors can be used to directly image magnetic fields at surfaces. They offer high resolution, high sensitivity, operability from cryogenic to room temperature, and linearity. We have fabricated hall sensors on GaAs / Al0.35Ga0.65As and GaAs / Al0.3Ga0.7As heterostructures, one containing a 2D electron gas 40 nanometers below the surface and another 140nm below the surface, as well as an In0.5Al0.5As / GaSb / AlSb / InAs heterostructure containing a 2DEG 21nm below the surface. The sensitive areas of our probes range from microns to 60nm on a side. We report on the field sensitivities of the probes and their spatial resolution in a scanning configuration.

  18. Supercurrent in the quantum Hall regime

    NASA Astrophysics Data System (ADS)

    Wei, Ming-Tso; Amet, François; Ke, Chung-Ting; Borzenets, Ivan; Wang, Jiyingmei; Watanabe, Keji; Taniguchi, Takashi; Deacon, Russell; Yamamoto, Michihisa; Bomze, Yuriy; Tarucha, Seigo; Finkelstein, Gleb

    Combining superconductivity and the quantum Hall (QH) effect is a promising route for creating new types of topological excitations. Despite this potential, signatures of superconductivity in the quantum Hall regime remain scarce, and a superconducting current through a QH weak link has so far eluded experimental observation. Here we demonstrate the existence of a novel type of Josephson coupling through a QH region at magnetic fields as high as 2 Tesla. The supercurrent is mediated by states encompassing QH edge channels, which are flowing on opposite sides of the sample. The edges are coupled together by the hybrid electron-hole modes at the interfaces between the QH region and the superconducting contacts. These chiral modes, which share some features with Majorana modes, are formed when electron and hole edge states are mixed by the superconductor.

  19. Learning Cities as Healthy Green Cities: Building Sustainable Opportunity Cities

    ERIC Educational Resources Information Center

    Kearns, Peter

    2012-01-01

    This paper discusses a new generation of learning cities we have called EcCoWell cities (Economy, Community, Well-being). The paper was prepared for the PASCAL International Exchanges (PIE) and is based on international experiences with PIE and developments in some cities. The paper argues for more holistic and integrated development so that…

  20. Multipole expansion in the quantum hall effect

    NASA Astrophysics Data System (ADS)

    Cappelli, Andrea; Randellini, Enrico

    2016-03-01

    The effective action for low-energy excitations of Laughlin's states is obtained by systematic expansion in inverse powers of the magnetic field. It is based on the W- infinity symmetry of quantum incompressible fluids and the associated higher-spin fields. Besides reproducing the Wen and Wen-Zee actions and the Hall viscosity, this approach further indicates that the low-energy excitations are extended objects with dipolar and multipolar moments.

  1. SERVIR Town Hall - Connecting Space to Village

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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.

  2. The Hall D Physics Program at JLab

    SciTech Connect

    Leckey, John P.

    2012-09-01

    GlueX is one of the flagship experiments of the 12 GeV era at the Thomas Jefferson National Accelerator Facility (JLab). The energy of the electron accelerator at JLab is presently undergoing an upgrade from 6 GeV to 12 GeV and a 4th experimental hall (Hall D) is being added. The GlueX experimental apparatus consists of a tagged coherent bremsstrahlung photon beam incident on a liquid hydrogen target. The photoproduced mesons, which are created inside of a 2.2 T solenoid, will then pass through a pair of drift chambers and eventually deposit their energy into either of two calorimeters, depending on their respective angles. GlueX will attempt to map out the light meson spectrum and search for meson-gluon hybrids to better understand the confinement of quarks and gluons in quantum chromodynamics (QCD). There is little data on the photoproduction of light mesons and the GlueX experiment will exceed the current photoproduction data by several orders of magnitude in the first year alone. Photoproduction is specifically well suited to search for meson-gluon hybrids because in the flux tube model the production cross-sections are higher for meson-gluon hybrids from photons, with the spins of the virtual quark-antiquark pair aligned, than from other sources such as pions, with the spins of the quark-antiquark pair anti-aligned. There are also other Hall D experiments proposed to look for physics beyond the Standard Model by studying Eta rare or forbidden decay channels such as eta to two neutral pions. The 12 GeV upgrade of the JLab accelerator and the complete physics program of Hall D will be presented.

  3. Electron-wall Interaction in Hall Thrusters

    SciTech Connect

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

    2005-02-11

    Electron-wall interaction effects in Hall thrusters are studied through measurements of the plasma response to variations of the thruster channel width and the discharge voltage. The discharge voltage threshold is shown to separate two thruster regimes. Below this threshold, the electron energy gain is constant in the acceleration region and therefore, secondary electron emission (SEE) from the channel walls is insufficient to enhance electron energy losses at the channel walls. Above this voltage threshold, the maximum electron temperature saturates.

  4. High temperature Hall-effect apparatus

    NASA Technical Reports Server (NTRS)

    Wood, C.; Lockwood, A.; Chmielewski, A.; Parker, J.; Zoltan, A.

    1984-01-01

    A high-temperature Hall-effect apparatus is described which allows measurements up to temperatures greater than 1200 K using the van der Pauw method. The apparatus was designed for measurements on refractory materials having high charge carrier concentrations and generally low mobilities. Pressure contacts are applied to the samples. Consequently, special contacting methods, peculiar to a specific sample material, are not required. The apparatus has been semiautomated to facilitate measurements. Results are presented on n- and p-type silicon.

  5. Box City Curriculum.

    ERIC Educational Resources Information Center

    Center for Understanding the Built Environment, Prairie Village, KS.

    This curriculum packet contains two lesson plans about cities and architecture intended for use with students in upper elementary grades and middle schools. The first lesson plan, "City People, City Stories" (Jan Ham), states that understanding architecture and cities must begin with an understanding of the people of the city. The children create…

  6. Hall magnetic reconnection: Guide field dependence

    SciTech Connect

    Huba, J.D.

    2005-01-01

    Two-dimensional Hall magnetohydrodynamic simulations are used to study the dependence of a guide field on magnetic reconnection. The simulations are run until a steady state is achieved for B{sub gf}/B{sub 0}=0, 0.1, 0.2, 0.5, 1.0, 2.0, and 5.0 where B{sub gf} is the guide field and B{sub 0} is the reversed field. It is found that the reconnection rate and plasma energization are reduced for increasing guide field strength. This is caused by a JxB force associated with Hall currents and the guide field that reduce the inflow and outflow velocities. However, the reconnection rate and plasma energization are only reduced by a factor of 2 for B{sub gf}=5B{sub 0}. Additionally, the quadrupole field associated with Hall reconnection is eliminated for B{sub gf}{approx_equal}B{sub 0}/3. Applications to magnetospheric plasmas are discussed.

  7. Spin Hall Effect in Disordered Organic Solids

    NASA Astrophysics Data System (ADS)

    Yu, Z. G.

    2015-07-01

    We study the spin Hall effect (SHE) in disordered π -conjugated organic solids, where individual molecules are oriented randomly and electrical conduction is via carrier hopping. The SHE, which arises from interference between direct (i →j ) and indirect (i →k →j ) hoppings in a triad consisting of three molecules i , j , and k , is found to be proportional to λ (ni×nj+nj×nk+nk×ni), where λ is the spin admixture of π electrons due to the spin-orbit coupling and ni is the orientation vector of molecule i . Electrical conductivity σq q (q =x ,y ,z ) and spin Hall conductivity σsh are computed by numerically solving the master equations of a system containing 32 ×32 ×32 molecules and summing over contributions from all triads in the system. The obtained value of the spin Hall angle Θsh is consistent with experimental data in PEDOT:PSS, with a predicted temperature dependence of log Θsh˜T-1 /4 .

  8. Generic superweak chaos induced by Hall effect.

    PubMed

    Ben-Harush, Moti; Dana, Itzhack

    2016-05-01

    We introduce and study the "kicked Hall system" (KHS), i.e., charged particles periodically kicked in the presence of uniform magnetic (B) and electric (E) fields that are perpendicular to each other and to the kicking direction. We show that for resonant values of B and E and in the weak-chaos regime of sufficiently small nonintegrability parameter κ (the kicking strength), there exists a generic family of periodic kicking potentials for which the Hall effect from B and E significantly suppresses the weak chaos, replacing it by "superweak" chaos (SWC). This means that the system behaves as if the kicking strength were κ^{2} rather than κ. For E=0, SWC is known to be a classical fingerprint of quantum antiresonance, but it occurs under much less generic conditions, in particular only for very special kicking potentials. Manifestations of SWC are a decrease in the instability of periodic orbits and a narrowing of the chaotic layers, relative to the ordinary weak-chaos case. Also, for global SWC, taking place on an infinite "stochastic web" in phase space, the chaotic diffusion on the web is much slower than the weak-chaos one. Thus, the Hall effect can be relatively stabilizing for small κ. In some special cases, the effect is shown to cause ballistic motion for almost all parameter values. The generic global SWC on stochastic webs in the KHS appears to be the two-dimensional closest analog to the Arnol'd web in higher dimensional systems. PMID:27300880

  9. Generic superweak chaos induced by Hall effect

    NASA Astrophysics Data System (ADS)

    Ben-Harush, Moti; Dana, Itzhack

    2016-05-01

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

  10. Anode Fall Formation in a Hall Thruster

    SciTech Connect

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

    2004-06-29

    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.

  11. Vibrational modes in the quantum Hall system

    NASA Astrophysics Data System (ADS)

    Wooten, Rachel; Yan, Bin; Daily, Kevin; Greene, Chris H.

    The hyperspherical adiabatic technique is more familiar to atomic and nuclear few-body systems, but can also be applied with high accuracy to the many-body quantum Hall problem. This technique reformulates the Schrödinger equation for N electrons into hyperspherical coordinates, which, after extracting the trivial center of mass, describes the system in terms of a single global size coordinate known as the hyperradius R, and 2 N - 3 remaining internal angular coordinates. The solutions are approximately separable in the hyperradial coordinate, and solutions in the system are found by treating the hyperradius as an adiabatic coordinate. The approximate separability of the wave functions in this coordinate suggests the presence of hyperradial vibrational modes which are not described in conventional theories. The vibrationally excited states share the internal geometry of their quantum Hall ground states, and their excitation frequencies may vary with the number of participating particles or the strength of the confinement. We plan to discuss the features of these vibrational modes and their possible detection in quantum Hall systems. NSF.

  12. A Magnetic Balance with Hall Effect Sensors

    NASA Astrophysics Data System (ADS)

    Sawada, Hideo; Kunimasu, Tetsuya; Suda, Shinichi; Mizoguti, Yasushi; Okada, Takumi

    Magnetic force acting on a model fixed at the center of the JAXA 60cm MSBS was measured with an industry manufactured balance system when MSBS control coil currents were varied. At the same time, magnetic field intensity was also measured with 11 Hall sensors, which were arranged around the MSBS test section. From relations between coil currents and its corresponding controlled magnetic forces, regressive curves were given and maximum deviation from the curves was evaluated. From relations between Hall sensor outputs and the magnetic forces, regressive curves and deviation were also obtained. Obtained results show Hall sensor outputs are much better indexes of balance than the coil currents. The maximum deviations were reduced to a half or one-third times as much as those evaluated using the control coil currents. However, when couples acting on the model are controlled, they are not effective to reduce hysteresis phenomenon in the relation. The deviation can be reduced by decreasing the range of calibration. Then, the error of the balance of the MSBS was reduced to about 1% of the calibration range.

  13. Stacking order dependence of inverse spin Hall effect and anomalous Hall effect in spin pumping experiments

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Il; Kim, Dong-Jun; Seo, Min-Su; Park, Byong-Guk; Park, Seung-Young

    2015-05-01

    The dependence of the measured DC voltage on the non-magnetic material (NM) in NM/CoFeB and CoFeB/NM bilayers is studied under ferromagnetic resonance conditions in a TE011 resonant cavity. The directional change of the inverse spin Hall effect (ISHE) voltage VISHE for the stacking order of the bilayer can separate the pure VISHE and the anomalous Hall effect (AHE) voltage VAHE utilizing the method of addition and subtraction. The Ta and Ti NMs show a broad deviation of the spin Hall angle θISH, which originates from the AHE in accordance with the high resistivity of NMs. However, the Pt and Pd NMs show that the kinds of NMs with low resistivity are consistent with the previously reported θISH values. Therefore, the characteristics that NM should simultaneously satisfy to obtain a reasonable VISHE value in bilayer systems are large θISH and low resistivity.

  14. Geometric Aspects of Quantum Hall States

    NASA Astrophysics Data System (ADS)

    Gromov, Andrey

    Explanation of the quantization of the Hall conductance at low temperatures in strong magnetic field is one of the greatest accomplishments of theoretical physics of the end of the 20th century. Since the publication of the Laughlin's charge pumping argument condensed matter theorists have come a long way to topological insulators, classification of noninteracting (and sometimes interacting) topological phases of matter, non-abelian statistics, Majorana zero modes in topological superconductors and topological quantum computation---the framework for "error-free'' quantum computation. While topology was very important in these developments, geometry has largely been neglected. We explore the role of space-time symmetries in topological phases of matter. Such symmetries are responsible for the conservation of energy, momentum and angular momentum. We will show that if these symmetries are maintained (at least on average) then in addition to Hall conductance there are other, in principle, measurable transport coefficients that are quantized and sensitive to topological phase transition. Among these coefficients are non-dissipative viscosity of quantum fluids, known as Hall viscosity; thermal Hall conductance, and a recently discovered coefficient---orbital spin variance. All of these coefficients can be computed as linear responses to variations of geometry of a physical sample. We will show how to compute these coefficients for a variety of abelian and non-abelian quantum Hall states using various analytical tools: from RPA-type perturbation theory to non-abelian Chern-Simons-Witten effective topological quantum field theory. We will explain how non-Riemannian geometry known as Newton-Cartan (NC) geometry arises in the computation of momentum and energy transport in non-relativistic gapped systems. We use this geometry to derive a number of thermodynamic relations and stress the non-relativistic nature of condensed matter systems. NC geometry is also useful in the

  15. A non-invasive Hall current distribution measurement system for Hall Effect thrusters

    NASA Astrophysics Data System (ADS)

    Mullins, Carl Raymond

    A direct, accurate method to measure thrust produced by a Hall Effect thruster on orbit does not currently exist. The ability to calculate produced thrust will enable timely and precise maneuvering of spacecraft---a capability particularly important to satellite formation flying. The means to determine thrust directly is achievable by remotely measuring the magnetic field of the thruster and solving the inverse magnetostatic problem for the Hall current density distribution. For this thesis, the magnetic field was measured by employing an array of eight tunneling magnetoresistive (TMR) sensors capable of milligauss sensitivity when placed in a high background field. The array was positioned outside the channel of a 1.5 kW Colorado State University Hall thruster equipped with a center-mounted electride cathode. In this location, the static magnetic field is approximately 30 Gauss, which is within the linear operating range of the TMR sensors. Furthermore, the induced field at this distance is greater than tens of milligauss, which is within the sensitivity range of the TMR sensors. Due to the nature of the inverse problem, the induced-field measurements do not provide the Hall current density by a simple inversion; however, a Tikhonov regularization of the induced field along with a non-negativity constraint and a zero boundary condition provides current density distributions. Our system measures the sensor outputs at 2 MHz allowing the determination of the Hall current density distribution as a function of time. These data are shown in contour plots in sequential frames. The measured ratios between the average Hall current and the discharge current ranged from 0.1 to 10 over a range of operating conditions from 1.3 kW to 2.2 kW. The temporal inverse solution at 2.0 kW exhibited a breathing mode of 37 kHz, which was in agreement with temporal measurements of the discharge current.

  16. Clean Cities Fact Sheet

    SciTech Connect

    Not Available

    2004-01-01

    This fact sheet explains the Clean Cities Program and provides contact information for all coalitions and regional offices. It answers key questions such as: What is the Clean Cities Program? What are alternative fuels? How does the Clean Cities Program work? What sort of assistance does Clean Cities offer? What has Clean Cities accomplished? What is Clean Cities International? and Where can I find more information?

  17. Giant Room Temperature Interface Spin Hall and Inverse Spin Hall Effects

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Wesselink, R. J. H.; Liu, Yi; Yuan, Zhe; Xia, Ke; Kelly, Paul J.

    2016-05-01

    The spin Hall angle (SHA) is a measure of the efficiency with which a transverse spin current is generated from a charge current by the spin-orbit coupling and disorder in the spin Hall effect (SHE). In a study of the SHE for a Pt |Py (Py =Ni80Fe20 ) bilayer using a first-principles scattering approach, we find a SHA that increases monotonically with temperature and is proportional to the resistivity for bulk Pt. By decomposing the room temperature SHE and inverse SHE currents into bulk and interface terms, we discover a giant interface SHA that dominates the total inverse SHE current with potentially major consequences for applications.

  18. Supersymmetric Quantum-Hall Effect on a Fuzzy Supersphere

    SciTech Connect

    Hasebe, Kazuki

    2005-05-27

    Supersymmetric quantum-Hall liquids are constructed on a supersphere in a supermonopole background. We derive a supersymmetric generalization of the Laughlin wave function, which is a ground state of a hard-core OSp(1 vertical bar 2) invariant Hamiltonian. We also present excited topological objects, which are fractionally charged deficits made by super Hall currents. Several relations between quantum-Hall systems and their supersymmetric extensions are discussed.

  19. Factors Affecting the Efficiency of Krypton Hall Thrusters

    NASA Technical Reports Server (NTRS)

    Hofer, Richard R.; Peterson, Peter Y.; Jacobson, David T.; Manzella, David M.

    2004-01-01

    The krypton-fueled Hall thruster offers the possibility of high-specific impulse and long lifetime. NASA's series of Hall thrusters have demonstrated krypton efficiencies only 5 - 15% less than xenon. Larger thrusters have smaller differences in efficiency. Plasma measurements have demonstrated that efficiency is reduced due to a decrease in mass utilization. Current efforts are considering the implications of these results, and how design changes can be made to increase the efficiency of krypton Hall thrusters.

  20. Basic Instrumentation for Hall A at Jefferson Jab

    SciTech Connect

    The Jefferson Lab Hall A Collaboration

    2003-07-01

    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.

  1. Faster Hall-Effect Current-Measuring Circuit

    NASA Technical Reports Server (NTRS)

    Sullender, Craig C.; Johnson, Daniel D.; Walker, Daniel D.

    1993-01-01

    Current-measuring circuit operates on Hall-effect-sensing and magnetic-field-nulling principles similar to those described in article, "Nulling Hall-Effect Current-Measuring Circuit" (LEW-15023), but simpler and responds faster. Designed without feedback loop, and analog pulse-width-modulated output indicates measured current. Circuit measures current at frequency higher than bandwidth of its Hall-effect sensor.

  2. Diagnostics Systems for Permanent Hall Thrusters Development

    NASA Astrophysics Data System (ADS)

    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

  3. Hall and Nernst effects in monolayer MoS2

    NASA Astrophysics Data System (ADS)

    Zhang, Yun-Hai; Zhang, Ming-Hua

    2016-03-01

    We study Hall and Nernst transports in monolayer MoS2 based on Green’s function formalism. We have derived analytical results for spin and valley Hall conductivities in the zero temperature and spin and valley Nernst conductivities in the low temperature. We found that tuning of the band gap and spin-orbit splitting can drive system transition from spin Hall insulator (SHI) to valley Hall insulator (VHI). When the system is subjected to a temperature gradient, the spin and valley Nernst conductivities are dependent on Berry curvature.

  4. Dynamic Feedback in Ferromagnet-Spin Hall Metal Heterostructures.

    PubMed

    Cheng, Ran; Zhu, Jian-Gang; Xiao, Di

    2016-08-26

    In ferromagnet-normal-metal heterostructures, spin pumping and spin-transfer torques are two reciprocal processes that occur concomitantly. Their interplay introduces a dynamic feedback effect interconnecting energy dissipation channels of both magnetization and current. By solving the spin diffusion process in the presence of the spin Hall effect in the normal metal, we show that the dynamic feedback gives rise to (i) a nonlinear magnetic damping that is crucial to sustain uniform steady-state oscillations of a spin Hall oscillator at large angles and (ii) a frequency-dependent spin Hall magnetoimpedance that reduces to the spin Hall magnetoresistance in the dc limit. PMID:27610880

  5. Probing magnetic microstructures with quasi-ballistic Hall crosses

    NASA Astrophysics Data System (ADS)

    Fasbender, S.; Schluck, J.; Cerchez, M.; Heinzel, T.; Sievers, S.; Pierz, K.; Schumacher, H. W.

    2016-03-01

    Hall sensing is performed on a localized magnetic field pattern using a quasi-ballistic Hall cross device. The Hall resistance shows a pronounced peak as a function of the magnetic field amplitude which is absent in the magnetization hysteresis loop. This non-monotonic response exemplifies qualitatively the failure of conventional Hall sensing. It is demonstrated how, by using a numerical simulation based on the Landauer-Büttiker model, the amplitude of the magnetic field profile can be determined from such measurements.

  6. Charge carrier coherence and Hall effect in organic semiconductors

    DOE PAGESBeta

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

    2016-03-30

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

  7. 30. TURBINE HALL, ORIGINAL TURBO GENERATOR, FROM ABOVE, LOOKING SOUTHEAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. TURBINE HALL, ORIGINAL TURBO GENERATOR, FROM ABOVE, LOOKING SOUTHEAST - Philadelphia Electric Company, Richmond Power Station, Southeast end of Lewis Street along Delaware River, Philadelphia, Philadelphia County, PA

  8. 28. TURBINE HALL, ORIGINAL TURBO GENERATOR, LOOKING EAST Philadelphia ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. TURBINE HALL, ORIGINAL TURBO GENERATOR, LOOKING EAST - Philadelphia Electric Company, Richmond Power Station, Southeast end of Lewis Street along Delaware River, Philadelphia, Philadelphia County, PA

  9. 36. TURBINE HALL, NEW TURBO GENERATOR, LOOKING NORTHEAST Philadelphia ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. TURBINE HALL, NEW TURBO GENERATOR, LOOKING NORTHEAST - Philadelphia Electric Company, Richmond Power Station, Southeast end of Lewis Street along Delaware River, Philadelphia, Philadelphia County, PA

  10. 33. TURBINE HALL, ORIGINAL TURBO GENERATOR, INTACT CONDENSER Philadelphia ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. TURBINE HALL, ORIGINAL TURBO GENERATOR, INTACT CONDENSER - Philadelphia Electric Company, Richmond Power Station, Southeast end of Lewis Street along Delaware River, Philadelphia, Philadelphia County, PA

  11. 35. TURBINE HALL, NEW TURBO GENERATOR, LOOKING SOUTHEAST Philadelphia ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. TURBINE HALL, NEW TURBO GENERATOR, LOOKING SOUTHEAST - Philadelphia Electric Company, Richmond Power Station, Southeast end of Lewis Street along Delaware River, Philadelphia, Philadelphia County, PA

  12. Volumetric Hall Effect Tomography – A Feasibility Study

    PubMed Central

    Wen, Han

    2010-01-01

    Hall effect imaging is an ultrasound-based method of mapping spatial variations in the dielectric constants of an acoustically-uniform sample. This paper presents three-dimensional Hall effect images of phantoms obtained by scanning a single transducer across a two-dimensional grid, effectively simulating two-dimensional phased-array signal reception. The experiments demonstrate the feasibility of volumetric Hall effect tomography and show the advantage of volumetric scans over planar scans. The images reflect several limitations of the current scanning method and point to directions for further hardware development. The inherent limitations of Hall effect imaging are also discussed in light of these results. PMID:10604800

  13. double hung window details, hall window details, entrance door profiles ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    double hung window details, hall window details, entrance door profiles - Chopawamsic Recreational Demonstration Area - Cabin Camp 1, Help's Quarters, Prince William Forest Park, Triangle, Prince William County, VA

  14. Synchronization of spin-transfer torque oscillators by spin pumping, inverse spin Hall, and spin Hall effects

    SciTech Connect

    Elyasi, Mehrdad; Bhatia, Charanjit S.; Yang, Hyunsoo

    2015-02-14

    We have proposed a method to synchronize multiple spin-transfer torque oscillators based on spin pumping, inverse spin Hall, and spin Hall effects. The proposed oscillator system consists of a series of nano-magnets in junction with a normal metal with high spin-orbit coupling, and an accumulative feedback loop. We conduct simulations to demonstrate the effect of modulated charge currents in the normal metal due to spin pumping from each nano-magnet. We show that the interplay between the spin Hall effect and inverse spin Hall effect results in synchronization of the nano-magnets.

  15. Optical spin Hall effects in plasmonic chains.

    PubMed

    Shitrit, Nir; Bretner, Itay; Gorodetski, Yuri; Kleiner, Vladimir; Hasman, Erez

    2011-05-11

    Observation of optical spin Hall effects (OSHEs) manifested by a spin-dependent momentum redirection is presented. The effect occurring solely as a result of the curvature of the coupled localized plasmonic chain is regarded as the locally isotropic OSHE, while the locally anisotropic OSHE arises from the interaction between the optical spin and the local anisotropy of the plasmonic mode rotating along the chain. A wavefront phase dislocation was observed in a circular curvature, in which the dislocation strength was enhanced by the locally anisotropic effect. PMID:21513279

  16. Anomalous Hall Effect in a Kagome Ferromagnet

    NASA Astrophysics Data System (ADS)

    Ye, Linda; Wicker, Christina; Suzuki, Takehito; Checkelsky, Joseph; Joseph Checkelsky Team

    The ferromagnetic kagome lattice is theoretically known to possess topological band structures. We have synthesized large single crystals of a kagome ferromagnet Fe3Sn2 which orders ferromagnetically well above room temperature. We have studied the electrical and magnetic properties of these crystals over a broad temperature and magnetic field range. Both the scaling relation of anomalous Hall effect and anisotropic magnetic susceptibility show that the ferromagnetism of Fe3Sn2 is unconventional. We discuss these results in the context of magnetism in kagome systems and relevance to the predicted topological properties in this class of compounds. This research is supported by DMR-1231319.

  17. Segmented electrode hall thruster with reduced plume

    DOEpatents

    Fisch, Nathaniel J.; Raitses, Yevgeny

    2004-08-17

    An apparatus and method for thrusting plasma, utilizing a Hall thruster with segmented electrodes along the channel, which make the acceleration region as localized as possible. Also disclosed are methods of arranging the electrodes so as to minimize erosion and arcing. Also disclosed are methods of arranging the electrodes so as to produce a substantial reduction in plume divergence. The use of electrodes made of emissive material will reduce the radial potential drop within the channel, further decreasing the plume divergence. Also disclosed is a method of arranging and powering these electrodes so as to provide variable mode operation.

  18. Collective field theory for quantum Hall states

    NASA Astrophysics Data System (ADS)

    Laskin, M.; Can, T.; Wiegmann, P.

    2015-12-01

    We develop a collective field theory for fractional quantum Hall (FQH) states. We show that in the leading approximation for a large number of particles, the properties of Laughlin states are captured by a Gaussian free field theory with a background charge. Gradient corrections to the Gaussian field theory arise from the covariant ultraviolet regularization of the theory, which produces the gravitational anomaly. These corrections are described by a theory closely related to the Liouville theory of quantum gravity. The field theory simplifies the computation of correlation functions in FQH states and makes manifest the effect of quantum anomalies.

  19. Low-Power Magnetically Shielded Hall Thrusters

    NASA Astrophysics Data System (ADS)

    Conversano, Ryan William

    This dissertation presents an investigation of the applicability of magnetic shielding to low-power Hall thrusters as a means to significantly improve operational lifetime. The key life-limiting factors of conventional Hall thrusters, including ion-bombardment sputter erosion of the discharge channel and high-energy electron power deposition to the channel walls, have been investigated extensively for a wide range of thruster scales. As thruster power is reduced to the "miniature" (i.e. sub-500 W) power regime, the increased surface-to-volume ratio of the discharge channel and decreased thruster component sizes promotes increased plasma-wall interactions and susceptibility to overheating, thereby reducing thruster operational lifetime and performance. Although methods for compensating for these issues have been investigated, unshielded miniature Hall thrusters are generally limited to sub-45% anode efficiencies and maximum lifetimes on the order of 1,000 h. A magnetically shielded magnetic field topology aims to maintain a low electron temperature along the channel surfaces and a plasma potential near that of the discharge voltage along the entire surface of the discharge channel along its axial length. These features result in a reduction of the kinetic energy of ions that impact the channel surfaces to near to or below the sputtering threshold, thus preventing significant ion-bombardment erosion of the discharge channel. Improved confinement of high-energy electrons is another byproduct of the field structure, aiding in the reduction of electron power deposition to the channel. Magnetic shielding has been shown to dramatically reduce plasma-wall interactions on 4--6 kW Hall thrusters, resulting in significant increases in projected operational lifetimes with minimal effects to thruster performance. In an effort to explore the scalability of magnetic shielding to low-power devices, two magnetically shielded miniature Hall thrusters were designed, fabricated and

  20. On the potential distribution in Hall thrusters

    SciTech Connect

    Keidar, Michael; Gallimore, Alec D.; Raitses, Yevgeny; Boyd, Iain D.

    2004-09-27

    A model of the plasma flow in a Hall thruster channel is developed that takes into account the two-dimensional current conservation effect and relies on some experimental input parameters, such as magnetic field and electron temperature distribution. The model is an attempt to explain the experimentally found nonuniform potential distribution across the thruster channel. This effect is explained by the change of the electron mobility across a magnetic field due to the magnetic field gradient and due to the electron current along the magnetic field driven by the electron temperature gradient.

  1. Future Hypernuclear Program at JLAB Hall C

    SciTech Connect

    Satoshi Nakamura

    2005-05-01

    Encouraged by the success of the first hypernuclear spectroscopy through the (e,e'K+) reaction (JLab E89-009), a new improved experiment with a newly developed High resolution Kaon Spectrometer (HKS) and a new configuration of the electron spectrometer is planned at the JLab Hall C. The introduction of the HKS will improve by a factor of two, the energy resolution which was limited by the previous kaon spectrometer. The hypernuclear yield and the signal to noise ratio will be also improved by a factor of 50 and 10, respectively.

  2. Excitons in the Fractional Quantum Hall Effect

    DOE R&D Accomplishments Database

    Laughlin, R. B.

    1984-09-01

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

  3. Supercurrent in the quantum Hall regime

    NASA Astrophysics Data System (ADS)

    Amet, F.; Ke, C. T.; Borzenets, I. V.; Wang, J.; Watanabe, K.; Taniguchi, T.; Deacon, R. S.; Yamamoto, M.; Bomze, Y.; Tarucha, S.; Finkelstein, G.

    2016-05-01

    A promising route for creating topological states and excitations is to combine superconductivity and the quantum Hall (QH) effect. Despite this potential, signatures of superconductivity in the QH regime remain scarce, and a superconducting current through a QH weak link has been challenging to observe. We demonstrate the existence of a distinct supercurrent mechanism in encapsulated graphene samples contacted by superconducting electrodes, in magnetic fields as high as 2 tesla. The observation of a supercurrent in the QH regime marks an important step in the quest for exotic topological excitations, such as Majorana fermions and parafermions, which may find applications in fault-tolerant quantum computing.

  4. Supercurrent in the quantum Hall regime.

    PubMed

    Amet, F; Ke, C T; Borzenets, I V; Wang, J; Watanabe, K; Taniguchi, T; Deacon, R S; Yamamoto, M; Bomze, Y; Tarucha, S; Finkelstein, G

    2016-05-20

    A promising route for creating topological states and excitations is to combine superconductivity and the quantum Hall (QH) effect. Despite this potential, signatures of superconductivity in the QH regime remain scarce, and a superconducting current through a QH weak link has been challenging to observe. We demonstrate the existence of a distinct supercurrent mechanism in encapsulated graphene samples contacted by superconducting electrodes, in magnetic fields as high as 2 tesla. The observation of a supercurrent in the QH regime marks an important step in the quest for exotic topological excitations, such as Majorana fermions and parafermions, which may find applications in fault-tolerant quantum computing. PMID:27199424

  5. The City as Classroom.

    ERIC Educational Resources Information Center

    Bailey, Stephen K.

    The author gives a rationale for utilizing the city as a place to learn. The city has many problems and although logistics require that we conduct most education in the school building, the author argues for putting out best brains to the task of bringing the city to the classroom and to exploiting the city as a classroom when appropriate.…

  6. Geometry of Fractional Quantum Hall Fluids

    NASA Astrophysics Data System (ADS)

    Cho, Gil Young

    2015-03-01

    Fractional quantum Hall (FQH) fluids of two-dimensional electron gases (2DEG) in large magnetic fields are fascinating topological states of matter. As such they are characterized by universal properties such as their fractional quantum Hall conductivity, fractionally charged anyonic excitations and a degeneracy of topological origin on surfaces with the topology of a torus. Quite surprisingly these topological fluids also couple to the geometry on which the 2DEG resides and have universal responses to adiabatic changes in the geometry. These responses are given by a Wen-Zee term (which describes the coupling of the currents to the spin connection of the geometry) and a gravitational Chern-Simons term which reflects the universal energy and momentum transport along the edges of the FQH state. We use a field theory of the FQH states to derive these universal responses. To account for the coupling to the background geometry, we show that the concept of flux attachment needs to be modified and use it to derive the geometric responses from Chern-Simons theories. We show that the resulting composite particles minimally couple to the spin connection of the geometry. Taking account of the framing anomaly of the quantum Chern-Simons theories, we derive a consistent theory of geometric responses from the Chern-Simons effective field theories and from parton constructions, and apply it to both abelian and non-abelian states. This work was supported in part by the NSF Grant DMR-1408713.

  7. Undulator Hall Air Temperature Fault Scenarios

    SciTech Connect

    Sevilla, J.; Welch, J.; /SLAC

    2010-11-17

    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.

  8. Spin Hall Magnetoresistance in Metallic Bilayers.

    PubMed

    Kim, Junyeon; Sheng, Peng; Takahashi, Saburo; Mitani, Seiji; Hayashi, Masamitsu

    2016-03-01

    Spin Hall magnetoresistance (SMR) is studied in metallic bilayers that consist of a heavy metal (HM) layer and a ferromagnetic metal (FM) layer. We find a nearly tenfold increase of SMR in W/CoFeB compared to previously studied HM/ferromagnetic insulator systems. The SMR increases with decreasing temperature despite the negligible change in the W layer resistivity. A model is developed to account for the absorption of the longitudinal spin current to the FM layer, one of the key characteristics of a metallic ferromagnet. We find that the model not only quantitatively describes the HM layer thickness dependence of SMR, allowing accurate estimation of the spin Hall angle and the spin diffusion length of the HM layer, but also can account for the temperature dependence of SMR by assuming a temperature dependent spin polarization of the FM layer. These results illustrate the unique role a metallic ferromagnetic layer plays in defining spin transmission across the HM/FM interface. PMID:26991195

  9. Hypernuclear Spectroscopy at JLab Hall C

    SciTech Connect

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

    2010-03-01

    Since the 1st generation experiment, E89-009, which was successfully carried out as a pilot experiment of (e,e'K+) hypernuclear spectroscopy at JLab Hall C in 2000, precision hypernuclear spectroscopy by the (e,e'K+) reactions made considerable progress. It has evolved to the 2nd generation experiment, E01-011, in which a newly constructed high resolution kaon spectrometer (HKS) was installed and the “Tilt method” was adopted in order to suppress large electromagnetic background and to run with high luminosity. Preliminary high-resolution spectra of 7ΛHe and 28ΛAl together with that of 12ΛB that achieved resolution better than 500 keV(FWHM) were obtained. The third generation experiment, E05-115, has completed data taking with an experimental setup combining a new splitter magnet, high resolution electron spectrometer (HES) and the HKS used in the 2nd generation experiment. The data were accumulated with targets of 7Li, 9Be, 10B, 12C and 52Cr as well as with those of CH2 and H2O for calibration. The analysis is under way with particular emphasis of determining precision absolute hypernuclear masses. In this article, hypernuclear spectroscopy program in the wide mass range at JLab Hall C that has undergone three generation is described.

  10. A Preliminary Investigation of Hall Thruster Technology

    NASA Technical Reports Server (NTRS)

    Gallimore, Alec D.

    1997-01-01

    A three-year NASA/BMDO-sponsored experimental program to conduct performance and plume plasma property measurements on two Russian Stationary Plasma Thrusters (SPTs) has been completed. The program utilized experimental facilitates at the University of Michigan's Plasmadynamics and Electric Propulsion Laboratory (PEPL). The main features of the proposed effort were as follows: (1) Characterized Hall thruster (and arcjet) performance by measuring ion exhaust velocity with probes at various thruster conditions; (2) Used a variety of probe diagnostics in the thruster plume to measure plasma properties and flow properties including T(sub e) and n(sub e) ion current density and ion energy distribution, and electric fields by mapping plasma potential; (3) Used emission spectroscopy to identify species within the plume and to measure electron temperatures. A key and unique feature of our research was our collaboration with Russian Hall thruster researcher Dr. Sergey A Khartov, Deputy Dean of International Relations at the Moscow Aviation Institute (MAI). His activities in this program included consulting on and participation in research at PEPL through use of a MAI-built SPT and ion energy probe.

  11. Electron-wall interaction in Hall thrusters

    SciTech Connect

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

    2005-05-15

    Electron-wall interaction effects in Hall thrusters are studied through measurements of the plasma response to variations of the thruster channel width and the discharge voltage. The discharge voltage threshold is shown to separate two thruster regimes. Below this threshold, the electron energy gain is constant in the acceleration region and therefore, secondary electron emission (SEE) from the channel walls is insufficient to enhance electron energy losses at the channel walls. Above this voltage threshold, the maximum electron temperature saturates. This result seemingly agrees with predictions of the temperature saturation, which recent Hall thruster models explain as a transition to space-charge saturated regime of the near-wall sheath. However, in the experiment, the maximum saturation temperature exceeds by almost three times the critical value estimated under the assumption of a Maxwellian electron energy distribution function. The channel narrowing, which should also enhance electron-wall collisions, causes unexpectedly larger changes of the plasma potential distribution than does the increase of the electron temperature with the discharge voltage. An enhanced anomalous crossed-field mobility (near wall or Bohm-type) is suggested by a hydrodynamic model as an explanation to the reduced electric field measured inside a narrow channel. We found, however, no experimental evidence of a coupling between the maximum electron temperature and the location of the accelerating voltage drop, which might have been expected due to the SEE-induced near-wall conductivity.

  12. Kinetic effects in a Hall thruster discharge

    SciTech Connect

    Kaganovich, I. D.; Raitses, Y.; Sydorenko, D.; Smolyakov, A.

    2007-05-15

    Recent analytical studies and particle-in-cell simulations suggested that the electron velocity distribution function in ExB discharge of annular geometry Hall thrusters is non-Maxwellian and anisotropic. The average kinetic energy of electron motion in the direction parallel to the thruster channel walls (across the magnetic field) is several times larger than that in the direction normal to the walls. Electrons are stratified into several groups depending on their origin (e.g., plasma or channel walls) and confinement (e.g., lost on the walls or trapped in the plasma). Practical analytical formulas are derived for the plasma flux to the wall, secondary electron fluxes, plasma potential, and electron cross-field conductivity. Calculations based on these formulas fairly agree with the results of numerical simulations. The self-consistent analysis demonstrates that the elastic electron scattering in collisions with atoms and ions plays a key role in formation of the electron velocity distribution function and the plasma potential with respect to the walls. It is shown that the secondary electron emission from the walls may significantly enhance the electron conductivity across the magnetic field but only weakly affects the insulating properties of the near-wall sheath. Such self-consistent decoupling between the secondary electron emission effects on the electron energy losses and the electron cross-field transport is currently not captured by the existing fluid and hybrid models of Hall thrusters.

  13. Hall Effect Measured Using a Waveguide Tee

    NASA Astrophysics Data System (ADS)

    Coppock, Joyce; Anderson, James; Johnson, William

    2014-03-01

    We describe a simple microwave apparatus to measure the Hall effect in semiconductor wafers. The advantage of this technique is that it does not require contacts on the sample or the use of a resonant cavity. Our method consists of placing the semiconductor wafer into a slot cut in an X-band waveguide tee, which lies in the center of an electromagnet, injecting power into the two opposing arms of the tee, and measuring the output at the third arm. Application of a magnetic field gives a Hall signal that is linear in the magnetic field and which reverses phase when the magnetic field is reversed. This method yields the semiconductor mobility, which we can compare for calibration purposes with mobility data from direct-current (Van der Pauw1) measurements. We are in the process of modeling the system using a finite-difference time-domain (FDTD) simulation to better understand the behavior of the electric fields inside the sample. Resistivity data is obtained by measuring the microwave reflection coefficient of the sample. This talk presents data for silicon and germanium samples doped with boron or phosphorus. Measured mobilities ranged from 270-3000 cm2/V.s . 1L. J. van der Pauw, PhilipsResearchReports 13, 1 (1958)

  14. Repurposing the Caltech Robinson Hall Coelostat

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

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

  15. New melting transition in Quantum Hall systems

    NASA Astrophysics Data System (ADS)

    Simion, George; Lin, Tsuging; Watson, John D.; Manfra, Michael J.; Csathy, Gabor; Rokhinson, Leonid; Lyanda-Geller, Yuli

    2014-03-01

    We discover a new melting transition caused by topological excitations of two dimensional electrons in the quantum Hall regime. Experimentally, strain dependence of resistivity changes sign upon crossing filling-factor-specified boundaries of reentrant integer quantum Hall effect (RIQHE) states. This observation violates the symmetry of electron bubble crystal, whose melting was thought to be responsible for insulator to metal transition in the range of RIQHE filling factors. We demonstrate theoretically that electron bubbles become elongated in the vicinity of charge defects and form textures of finite size. Textures lower the energy of excitations. In the two-electron bubble crystal these textures form hedgehogs (vortices) around defects having (lacking) one extra electron. At low density these textures form an insulating Abrikosov lattice. At densities sufficient to cause the textures to overlap, their interactions are described by the XY-model and the defect lattice melts. This explains the sharp metal-insulator transition observed in finite temperature conductivity measurements. In this regime, melting is a function of several variables and forms a continuous phase boundary in the field-temperature (B - T) plane. Research was partially supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Awards DE-SC0010544 (Y.L-G), DE-SC0008630 (L.P.R.), DE-SC0006671 (G.S. and M.M.).

  16. New topological excitations in quantum Hall systems

    NASA Astrophysics Data System (ADS)

    Lyanda-Geller, Yuli; Lin, Tsuging; Simion, George; Watson, John D.; Manfra, Michael J.; Csathy, Gabor; Rokhinson, Leonid

    2014-03-01

    We discover new topological excitations of two dimensional electrons in the quantum Hall regime. The strain dependence of resistivity observed experimentally is shown to change sign upon crossing filling-factor-specified boundaries of reentrant integer quantum Hall effect (RIQHE) states. This observation violates the known symmetry of electron bubbles thought to be responsible for the RIQHE. We demonstrate theoretically that electron bubbles become elongated in the vicinity of charge defects and form textures of finite size. Calculations confirm that textures lower the energy of excitations. In the two-electron bubble crystal these textures form two-dimensional hedgehogs around defects having one extra electron, and vortices around defects lacking one electron. Strain affects vortices and hedgehogs differently, explaining striking strain-dependent resistivity. The sharp transition from insulating RIQHE state to conducting state is caused by melting of Abrikosov crystal comprised of the defects. The proposed physical mechanism of conductivity due to topological defects is shown to lead to an unusually large magnitude of the strain effect on resistivity in the range of RIQHE filling factors, in agreement with experiment. Research was partially supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Awards DE-SC0010544 (Y.L-G), DE-SC0008630 (L.P.R.), DE-SC0006671 (G.S. and M.M.).

  17. Cylindrical Hall Thrusters with Permanent Magnets

    SciTech Connect

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

    2010-10-18

    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. __________________________________________________

  18. Pair spectrometer hodoscope for Hall D at Jefferson Lab

    DOE PAGESBeta

    Barbosa, Fernando J.; Hutton, Charles L.; Sitnikov, Alexandre; Somov, Alexander S.; Somov, S.; Tolstukhin, Ivan

    2015-09-21

    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.

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

    ERIC Educational Resources Information Center

    Rizvi, Fazal

    2015-01-01

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

  20. Varsity Hall: The Infirmary at the University of Virginia

    ERIC Educational Resources Information Center

    Christmas, William A.; Turner, James C.

    2008-01-01

    In the past 5 years, an important treasure for the field of college health was rediscovered and has been completely renovated. It is the original student infirmary, now called Varsity Hall, at the University of Virginia in Charlottesville. Varsity Hall is a significant rediscovery for those who are interested in the history of college health. This…

  1. Useful Pedagogical Applications of the Classical Hall Effect

    ERIC Educational Resources Information Center

    Houari, Ahmed

    2007-01-01

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

  2. High Life: 17th Annual Residence Hall Construction Report

    ERIC Educational Resources Information Center

    Agron, Joe

    2006-01-01

    Residence hall construction continues to be a priority for colleges and universities. With enrollments on the upswing, higher-education institutions are spending more and building larger facilities to entice students to live on campus. This article presents the findings of "American School & University's" 17th annual Residence Hall Construction…

  3. Acoustic Requirements for a Multi-Purpose Hall.

    ERIC Educational Resources Information Center

    Schulte, W. Allen

    2002-01-01

    This case study examines the proposed design of a new lecture/recital hall in Centennial Hall at Lynchburg College that will be used for lectures, public events, a film studies course, and musical recitals. It explores the audio-visual challenges presented by the differing acoustical requirements for the building. (EV)

  4. INTERIOR VIEW OF DINING ROOM. LANAI AND HALL TO THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF DINING ROOM. LANAI AND HALL TO THE LEFT. NOTE THE TELEPHONE NICHE IN THE HALL. PANTRY AND KITCHEN THROUGH THE DOORWAY AT THE RIGHT. VIEW FACING WEST. - Hickam Field, Officers' Housing Type G, 205 Seventh Street, Honolulu, Honolulu County, HI

  5. Hall-Effect Thruster Utilizing Bismuth as Propellant

    NASA Technical Reports Server (NTRS)

    Szabo, James; Gasdaska, Charles; Hruby, Vlad; Robin, Mike

    2008-01-01

    A laboratory-model Hall-effect spacecraft thruster was developed that utilizes bismuth as the propellant. Xenon was used in most prior Hall-effect thrusters. Bismuth is an attractive alternative because it has a larger atomic mass, a larger electron-impact-ionization cross-section, and is cheaper and more plentiful.

  6. Whose Big Prize? A Response to Hall and Gunter

    ERIC Educational Resources Information Center

    Furlong, John

    2009-01-01

    This article presents the author's response to Hall and Gunter who accuse the author of trying to mount "a stout defence" of New Labour's reforms of the teaching profession. Hall and Gunter go further and accuse the author of "triumphalism" in his use of the title "Tony Blair's big prize". Their second and more serious challenge concerns the…

  7. A Model for Developing New Residence Hall Environments

    ERIC Educational Resources Information Center

    Hubbell, Robert N.; Sherwood, Grant P.

    1973-01-01

    This paper has the function of developing a residence hall interaction model utilizing three components: environmental options, student development needs, and human interaction categories. The paper discussed ways in which residence hall staff members could effect optimal learning opportunities by matching various environmental options to…

  8. Magnonic Hall effect and topological magnonic crystals (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Murakami, Shuichi

    2015-09-01

    In electronic systems it is well established that when there is a magnetic field or spontaneous magnetization, the Hall effect, and in some cases the quantum Hall effect appears. We theoretically pursue analogs of these phenomena in magnons (spin waves) and plasmons. In the case of magnons in ferromagnets, the Hall effect or quantum Hall effect requires some kind of a spin-orbit coupling (similar to electronic systems), and we show that the dipolar interaction, as well as the Dyaloshinskii-Moriya interaction, plays the role. By calculating the Berry curvature from the wavefunction, we can calculate thermal Hall effect for magnons in ferromagnets with dipolar interaction. We found that only the magnetostatic forward volume-wave mode exhibits the thermal Hall effect while the backward mode and the surface mode do not. In addition, by introducing some artificial spatial periodicity into the magnet, for example by fabricating nanostructures with two different magnets in a periodic structure or by making a periodic array of nanomagnets, we theoretically find appearance of quantum Hall effect in a certain range of the magnetic field. There appear chiral edge states which propagate along the edge of the magnet in one way. We call this a topological magnonic crystal. In the plasmon case, we should begin with constructing a fundamental band theory, and we theoretically show that on a metal surface with corrugations forming a triangular lattice under the magnetic field, the quantum Hall effect appears. It can be called a topological plasmonic crystal.

  9. A Larger Scale. Tenth Annual Residence Hall Construction Report.

    ERIC Educational Resources Information Center

    Argon, Joe

    1999-01-01

    Presents data from the American School & University's 10th Annual Residence Hall Construction Report that show dormitories are costing more per square foot to build while also becoming larger accommodations. Data tables are provided as are highlighted discussions that include residence hall design flexibility, environmental concerns and building…

  10. 35. Photographic copy of second floor plan of Bowditch Hall, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. Photographic copy of second floor plan of Bowditch Hall, Alfred Hopkins & Associates, 1943. Drawing on file at Caretaker Site Office, Naval Undersea Warfare Center, New London. Copyright-free. - Naval Undersea Warfare Center, Bowditch Hall, 600 feet east of Smith Street & 350 feet south of Columbia Cove, West bank of Thames River, New London, New London County, CT

  11. 34. Photographic copy of first floor plan of Bowditch Hall, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. Photographic copy of first floor plan of Bowditch Hall, Alfred Hopkins & Associates, 1943. Drawing on file at Caretaker Site Office, Naval Undersea Warfare Center, New London. Copyright-free. - Naval Undersea Warfare Center, Bowditch Hall, 600 feet east of Smith Street & 350 feet south of Columbia Cove, West bank of Thames River, New London, New London County, CT

  12. 36. Photographic copy of third floor plan of Bowditch Hall, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. Photographic copy of third floor plan of Bowditch Hall, Alfred Hopkins & Associates, 1943. Drawing on file at Caretaker Site Office, Naval Undersea Warfare Center, New London. Copyright-free. - Naval Undersea Warfare Center, Bowditch Hall, 600 feet east of Smith Street & 350 feet south of Columbia Cove, West bank of Thames River, New London, New London County, CT

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

    SciTech Connect

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

    2012-05-15

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

  14. Pair spectrometer hodoscope for Hall D at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Barbosa, F.; Hutton, C.; Sitnikov, A.; Somov, A.; Somov, S.; Tolstukhin, I.

    2015-09-01

    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.

  15. 30. VIEW OF DRILL HALL FROM SECOND FLOOR EAST BALCONY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. VIEW OF DRILL HALL FROM SECOND FLOOR EAST BALCONY FACING WEST. SHOWS ALTERNATE BAY X BRACING OF ROOF TRUSSES. ALSO SHOWS TRUSSES, WINDOWS IN THE MONITOR, STAIRWAY AT THE SOUTHWEST CORNER OF THE DRILL HALL AND THE THREE LEVELS OF BENCHES ON THE BALCONY. - Yakima National Guard Armory, 202 South Third Street, Yakima, Yakima County, WA

  16. G. Stanley Hall, Child Study, and the Teaching of Geography

    ERIC Educational Resources Information Center

    Koelsch, William A.

    2002-01-01

    G. Stanley Hall (1844-1924), founding president of Clark University, was a leader in the child study movement and a significant figure in psychology and education in the late nineteenth and early twentieth centuries. Hall had pronounced opinions on many educational subjects, including the teaching of geography. His criticisms and program for the…

  17. Contextual view of the Hall of Transportation from Yerba Buena ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view of the Hall of Transportation from Yerba Buena Island, showing Palace of Fine and Decorative Arts (Building 3) at far right, camera facing northwest - Golden Gate International Exposition, Hall of Transportation, 440 California Avenue, Treasure Island, San Francisco, San Francisco County, CA

  18. Magnetic Measurement of the Background Field in the Undulator Hall

    SciTech Connect

    Fisher, Andrew; Nuhn, Heinz-Dieter; Welch, James; /SLAC

    2010-11-18

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

  19. Quantum Hall effects in a non-Abelian honeycomb lattice

    NASA Astrophysics Data System (ADS)

    Li, Ling; Hao, Ningning; Liu, Guocai; Bai, Zhiming; Li, Zai-Dong; Chen, Shu; Liu, W. M.

    2015-12-01

    We study the tunable quantum Hall effects in a non-Abelian honeycomb optical lattice which is a multi-Dirac-point system. We find that the quantum Hall effects present different features with the change in relative strengths of several perturbations. Namely, the quantum spin Hall effect can be induced by gauge-field-dressed next-nearest-neighbor hopping, which, together with a Zeeman field, can induce the quantum anomalous Hall effect characterized by different Chern numbers. Furthermore, we find that the edge states of the multi-Dirac-point system represent very different features for different boundary geometries, in contrast with the generic two-Dirac-point system. Our study extends the borders of the field of quantum Hall effects in a honeycomb optical lattice with multivalley degrees of freedom.

  20. Formulation of the relativistic quantum Hall effect and parity anomaly

    NASA Astrophysics Data System (ADS)

    Yonaga, Kouki; Hasebe, Kazuki; Shibata, Naokazu

    2016-06-01

    We present a relativistic formulation of the quantum Hall effect on Haldane sphere. An explicit form of the pseudopotential is derived for the relativistic quantum Hall effect with/without mass term. We clarify particular features of the relativistic quantum Hall states with the use of the exact diagonalization study of the pseudopotential Hamiltonian. Physical effects of the mass term to the relativistic quantum Hall states are investigated in detail. The mass term acts as an interpolating parameter between the relativistic and nonrelativistic quantum Hall effects. It is pointed out that the mass term unevenly affects the many-body physics of the positive and negative Landau levels as a manifestation of the "parity anomaly." In particular, we explicitly demonstrate the instability of the Laughlin state of the positive first relativistic Landau level with the reduction of the charge gap.

  1. Unconventional quantum Hall effect in Floquet topological insulators

    NASA Astrophysics Data System (ADS)

    Tahir, M.; Vasilopoulos, P.; Schwingenschlögl, U.

    2016-09-01

    We study an unconventional quantum Hall effect for the surface states of ultrathin Floquet topological insulators in a perpendicular magnetic field. The resulting band structure is modified by photon dressing and the topological property is governed by the low-energy dynamics of a single surface. An exchange of symmetric and antisymmetric surface states occurs by reversing the light’s 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 {σyx}=0 at zero Fermi energy, to a Hall insulator state with {σyx}={{e}2}/2h . These findings open new possibilities for experimentally realizing nontrivial quantum states and unusual quantum Hall plateaus at (+/- 1/2,+/- 3/2,+/- 5/2,...){{e}2}/h .

  2. Unconventional quantum Hall effect in Floquet topological insulators.

    PubMed

    Tahir, M; Vasilopoulos, P; Schwingenschlögl, U

    2016-09-28

    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 light's 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 [Formula: see text] at zero Fermi energy, to a Hall insulator state with [Formula: see text]. These findings open new possibilities for experimentally realizing nontrivial quantum states and unusual quantum Hall plateaus at [Formula: see text]. PMID:27460419

  3. Asymmetric nonlinear response of the quantized Hall effect

    NASA Astrophysics Data System (ADS)

    Siddiki, A.; Horas, J.; Kupidura, D.; Wegscheider, W.; Ludwig, S.

    2010-11-01

    An asymmetric breakdown of the integer quantized Hall effect (IQHE) is investigated. This rectification effect is observed as a function of the current value and its direction in conjunction with an asymmetric lateral confinement potential defining the Hall bar. Our electrostatic definition of the Hall bar via Schottky gates allows a systematic control of the steepness of the confinement potential at the edges of the Hall bar. A softer edge (flatter confinement potential) results in more stable Hall plateaus, i.e. a breakdown at a larger current density. For one soft and one hard edge, the breakdown current depends on its direction, resembling rectification. This nonlinear magneto-transport effect confirms the predictions of an emerging screening theory of the IQHE.

  4. Topological insulator in junction with ferromagnets: Quantum Hall effects

    NASA Astrophysics Data System (ADS)

    Chudnovskiy, A. L.; Kagalovsky, V.

    2015-06-01

    The ferromagnet-topological insulator-ferromagnet (FM-TI-FM) junction exhibits thermal and electrical quantum Hall effects. The generated Hall voltage and transverse temperature gradient can be controlled by the directions of magnetizations in the FM leads, which inspires the use of FM-TI-FM junctions as electrical and as heat switches in spintronic devices. Thermal and electrical Hall coefficients are calculated as functions of the magnetization directions in ferromagnets and the spin-relaxation time in TI. Both the Hall voltage and the transverse temperature gradient decrease but are not completely suppressed even at very short spin-relaxation times. The Hall coefficients turn out to be independent of the spin-relaxation time for symmetric configuration of FM leads.

  5. Construction and Operation of a Differential Hall Element Magnetometer

    NASA Astrophysics Data System (ADS)

    Calkins, Matthew W.; Javernick, Philip D.; Quintero, Pedro A.; Calm, Yitzi M.; Meisel, Mark W.

    2012-02-01

    A Differential Hall Element Magnetometer (DHEM) was constructed to measure the magnetic saturation and coercive fields of small samples consisting of magnetic nanoparticles that may have biomedical applications. The device consists of two matched Hall elements that can be moved through the room temperature bore of a 9 Tesla superconducting magnet. The Hall elements are wired in opposition such that a null response, to within a small offset, is measured in the absence of a sample that may be located on top of one unit. A LabVIEW program controls the current through the Hall elements and measures the net Hall voltage while simultaneously moving the probe through the magnetic field by regulating a linear stepper motor. Ultimately, the system will be tested to obtain a figure of merit using successively smaller samples. Details of the apparatus will be provided along with preliminary data.

  6. Anomalous Hall effect in YIG|Pt bilayers

    SciTech Connect

    Meyer, Sibylle Schlitz, Richard; Geprägs, Stephan; Opel, Matthias; Huebl, Hans; Goennenwein, Sebastian T. B.; Gross, Rudolf

    2015-03-30

    We measure the ordinary and the anomalous Hall effect in a set of yttrium iron garnet|platinum (YIG|Pt) bilayers via magnetization orientation dependent magnetoresistance experiments. Our data show that the presence of the ferrimagnetic insulator YIG leads to an anomalous Hall effect like voltage in Pt, which is sensitive to both Pt thickness and temperature. Interpretation of the experimental findings in terms of the spin Hall anomalous Hall effect indicates that the imaginary part of the spin mixing conductance G{sub i} plays a crucial role in YIG|Pt bilayers. In particular, our data suggest a sign change in G{sub i} between 10 K and 300 K. Additionally, we report a higher order Hall effect contribution, which appears in thin Pt films on YIG at low temperatures.

  7. Hall viscosity and momentum transport in lattice and continuum models of the integer quantum Hall effect in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Tuegel, Thomas I.; Hughes, Taylor L.

    2015-10-01

    The Hall viscosity describes a nondissipative response to strain in systems with broken time-reversal symmetry. We develop a method for computing the Hall viscosity of lattice systems in strong magnetic fields based on momentum transport, which we compare to the method of momentum polarization used by Tu et al. [Phys. Rev. B 88, 195412 (2013), 10.1103/PhysRevB.88.195412] and Zaletel et al. [Phys. Rev. Lett. 110, 236801 (2013), 10.1103/PhysRevLett.110.236801] for noninteracting systems. We compare the Hall viscosity of square-lattice tight-binding models in magnetic field to the continuum integer quantum Hall effect (IQHE) showing agreement when the magnetic length is much larger than the lattice constant, but deviation as the magnetic field strength increases. We also relate the Hall viscosity of relativistic electrons in magnetic field (the Dirac IQHE) to the conventional IQHE. The Hall viscosity of the lattice Dirac model in magnetic field agrees with the continuum Dirac Hall viscosity when the magnetic length is much larger than the lattice constant. We also show that the Hall viscosity of the lattice model deviates further from the continuum model if the C4 symmetry of the square lattice is broken to C2, but the deviation is again minimized as the magnetic length increases.

  8. Quantum theory of bilayer quantum Hall smectics

    NASA Astrophysics Data System (ADS)

    Papa, Emiliano; Schliemann, John; MacDonald, A. H.; Fisher, Matthew P.

    2003-03-01

    Mean-field theory predicts that bilayer quantum Hall systems at odd integer total filling factors can have stripe ground states, in which the top Landau level is occupied alternately by electrons in one of the two layers. We report on an analysis of the properties of these states based on a coupled-Luttinger-liquid description that is able to account for quantum fluctuations of charge-density and position along each stripe edge. The soft modes associated with the broken symmetries of the stripe state lead to an unusual coupled-Luttinger-liquid system with strongly enhanced low-temperature heat capacity and strongly suppressed low-energy tunneling density of states. We assess the importance of the intralayer and interlayer backscattering terms in the microscopic Hamiltonian, which are absent in the Luttinger liquid description, by employing a perturbative renormalization group approach which rescales time and length along but not transverse to the stripes. With interlayer backscattering interactions present the Luttinger-liquid states are unstable either to an incompressible striped state that has spontaneous interlayer phase coherence and a sizable charge gap even at relatively large layer separations, or to Wigner crystal states. Our quantitative estimates of the gaps produced by backscattering interactions are summarized in Fig. 11 by a schematic phase diagram intended to represent predicted experimental findings in very high mobility bilayer systems at dilution refrigerator temperatures as a function of layer separation and bilayer density balance. We predict that the bilayer will form incompressible isotropic interlayer phase-coherent states for small layer separations, say d⩽1.5l. At larger interlayer spacings, however, the bilayer will tend to form one of several different anisotropic states depending on the layer charge balance, which we parametrize by the fractional filling factor ν contributed by one of the two layers. For large charge imbalances (

  9. Giant Room Temperature Interface Spin Hall and Inverse Spin Hall Effects.

    PubMed

    Wang, Lei; Wesselink, R J H; Liu, Yi; Yuan, Zhe; Xia, Ke; Kelly, Paul J

    2016-05-13

    The spin Hall angle (SHA) is a measure of the efficiency with which a transverse spin current is generated from a charge current by the spin-orbit coupling and disorder in the spin Hall effect (SHE). In a study of the SHE for a Pt|Py (Py=Ni_{80}Fe_{20}) bilayer using a first-principles scattering approach, we find a SHA that increases monotonically with temperature and is proportional to the resistivity for bulk Pt. By decomposing the room temperature SHE and inverse SHE currents into bulk and interface terms, we discover a giant interface SHA that dominates the total inverse SHE current with potentially major consequences for applications. PMID:27232030

  10. Mesoscopic spin Hall effect in semiconductor nanostructures

    NASA Astrophysics Data System (ADS)

    Zarbo, Liviu

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

  11. Propulsion Instruments for Small Hall Thruster Integration

    NASA Technical Reports Server (NTRS)

    Johnson, Lee K.; Conroy, David G.; Spanjers, Greg G.; Bromaghim, Daron R.

    2001-01-01

    Planning and development are underway for the propulsion instrumentation necessary for the next AFRL electric propulsion flight project, which includes both a small Hall thruster and a micro-PPT. These instruments characterize the environment induced by the thruster and the associated data constitute part of a 'user's manual' for these thrusters. Several instruments probe the back-flow region of the thruster plume, and the data are intended for comparison with detailed numerical models in this region. Specifically, an ion probe is under development to determine the energy and species distributions, and a Langmuir probe will be employed to characterize the electron density and temperature. Other instruments directly measure the effects of thruster operation on spacecraft thermal control surfaces, optical surfaces, and solar arrays. Specifically, radiometric, photometric, and solar-cell-based sensors are under development. Prototype test data for most sensors should be available, together with details of the instrumentation subsystem and spacecraft interface.

  12. Quantum spin Hall effect of light

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  13. Flux sensitivity of quantum spin Hall rings

    NASA Astrophysics Data System (ADS)

    Crépin, F.; Trauzettel, B.

    2016-01-01

    We analyze the periodicity of persistent currents in quantum spin Hall loops, partly covered with an s-wave superconductor, in the presence of a flux tube. Much like in normal (non-helical) metals, the periodicity of the single-particle spectrum goes from Φ0 = h / e to Φ0 / 2 as the length of the superconductor is increased past the coherence length of the superconductor. We further analyze the periodicity of the persistent current, which is a many-body effect. Interestingly, time reversal symmetry and parity conservation can significantly change the period. We find a 2Φ0-periodic persistent current in two distinct regimes, where one corresponds to a Josephson junction and the other one to an Aharonov-Bohm setup.

  14. Confinement of Fractional Quantum Hall States

    NASA Astrophysics Data System (ADS)

    Willett, Robert; Manfra, Michael; West, Ken; Pfeiffer, Loren

    2008-03-01

    Confinement of small-gapped fractional quantum Hall states facilitates quasiparticle manipulation and is an important step towards quasiparticle interference measurements. Demonstrated here is conduction through top gate defined, narrow channels in high density, ultra-high mobility heterostructures. Transport evidence for the persistence of a correlated state at filling fraction 5/3 is shown in channels of 2μm length but gated to near 0.3μm in width. The methods employed to achieve this confinement hold promise for interference devices proposed for studying potential non-Abelian statistics at filling fraction 5/2. R.L. Willett, M.J. Manfra, L.N. Pfeiffer, K.W. West, Appl. Phys. Lett. 91, 052105 (2007).

  15. OPTICS. Quantum spin Hall effect of light.

    PubMed

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

    2015-06-26

    Maxwell's equations, formulated 150 years ago, ultimately describe properties of light, from classical electromagnetism to quantum and relativistic aspects. The latter ones result in remarkable geometric and topological phenomena related to the spin-1 massless nature of photons. By analyzing fundamental spin properties of Maxwell waves, we show that free-space light exhibits an intrinsic quantum spin Hall effect—surface modes with strong spin-momentum locking. These modes are evanescent waves that form, for example, surface plasmon-polaritons at vacuum-metal interfaces. Our findings illuminate the unusual transverse spin in evanescent waves and explain recent experiments that have demonstrated the transverse spin-direction locking in the excitation of surface optical modes. This deepens our understanding of Maxwell's theory, reveals analogies with topological insulators for electrons, and offers applications for robust spin-directional optical interfaces. PMID:26113717

  16. Cathode Effects in Cylindrical Hall Thrusters

    SciTech Connect

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

    2008-09-12

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

  17. Cathode effects in cylindrical Hall thrusters

    SciTech Connect

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

    2008-11-15

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

  18. 50 KW Class Krypton Hall Thruster Performance

    NASA Technical Reports Server (NTRS)

    Jacobson, David T.; Manzella, David H.

    2003-01-01

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

  19. Spin Hall magnetoresistance at high temperatures

    SciTech Connect

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

    2015-02-02

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

  20. Algebraic geometry realization of quantum Hall soliton

    NASA Astrophysics Data System (ADS)

    Abounasr, R.; Ait Ben Haddou, M.; El Rhalami, A.; Saidi, E. H.

    2005-02-01

    Using the Iqbal-Netzike-Vafa dictionary giving the correspondence between the H2 homology of del Pezzo surfaces and p-branes, we develop a way to approach the system of brane bounds in M-theory on S1. We first review the structure of 10-dimensional quantum Hall soliton (QHS) from the view of M-theory on S1. Then, we show how the D0 dissolution in D2-brane is realized in M-theory language and derive the p-brane constraint equations used to define appropriately the QHS. Finally, we build an algebraic geometry realization of the QHS in type IIA superstring and show how to get its type IIB dual. Other aspects are also discussed.

  1. Geometrical Scaling of Hall Thruster Particle Model

    SciTech Connect

    Taccogna, Francesco; Longo, Savino; Capitelli, Mario; Schneider, Ralf

    2005-05-16

    Non-Maxwellian behaviour and plasma-wall interaction are key processes in the physics of Hall thrusters. For this purpose, a 2D{l_brace}r,z{r_brace}-3V axisymmetric fully kinetic Particle-in-Cell/Monte Carlo Collision (PIC-MCC) model of the acceleration channel including the process of secondary electron emission (SEE) from the dielectric walls has been developed. In order to make the simulation possible with regard to the computational time, a reduction of the thruster dimension was done. This was derived from a new physics-based scaling law. This model has demonstrated its outstanding capability in improving the physics insight into the processes in Stationary Plasma Thruster (SPT) and in reproducing accurately well experimental data.

  2. Radial spin Hall effect of light

    NASA Astrophysics Data System (ADS)

    Shu, Weixing; Ke, Yougang; Liu, Yachao; Ling, Xiaohui; Luo, Hailu; Yin, Xiaobo

    2016-01-01

    We propose and realize a radial spin Hall effect (SHE) of light by using a dielectric metasurface. The metasurface with radially varying optical axes introduces a Pancharatnam-Berry (PB) geometrical phase to the incident light. The spatial gradient of PB phase accounts for a shift in the momentum space and thus leads the light to split radially into two concentric rays with opposite spin in the position space, which is called a radial SHE. Further experiments verify that the magnitude of the splitting increases with the rotation rate of the optical-axis orientation and the propagation distance, thereby allowing for macroscopic observation of the SHE. We also find that the phase of the incident light influences the profiles of the two split rays, while the polarization determines their intensities. The results provide methods to tune the SHE of light by engineering metasurfaces and modulating the incident light, and this radial SHE may be extrapolated to other physical systems.

  3. Chaotic waves in Hall thruster plasma

    SciTech Connect

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

    2006-01-15

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

  4. Determination of the Hall Thruster Operating Regimes

    SciTech Connect

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

    2002-04-09

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

  5. Hall effect in a moving liquid

    NASA Astrophysics Data System (ADS)

    Di Lieto, Alberto; Giuliano, Alessia; Maccarrone, Francesco; Paffuti, Giampiero

    2012-01-01

    A simple experiment, suitable for performing in an undergraduate physics laboratory, illustrates electromagnetic induction through the water entering into a cylindrical rubber tube by detecting the voltage developed across the tube in the direction transverse both to the flow velocity and to the magnetic field. The apparatus is a very simple example of an electromagnetic flowmeter, a device which is commonly used both in industrial and physiological techniques. The phenomenology observed is similar to that of the Hall effect in the absence of an electric current in the direction of motion of the carriers. The experimental results show a dependence on the intensity of the magnetic field and on the carrier velocity, in good agreement with the theory. Discussion of the system, based on classical electromagnetism, indicates that the effect depends only on the flow rate, and is independent both of the velocity profile and of the electrical conductivity of the medium.

  6. A Preliminary Investigation of Hall Thruster Technology

    NASA Technical Reports Server (NTRS)

    Gallimore, Alec D.

    1997-01-01

    A three-year, NASA/BMDO-sponsored experimental program to conduct performance and plume plasma property measurements on two Russian Stationary Plasma Thrusters (SPTs) has been completed. The program utilized experimental facilitates at the University of Michigan's Plasmadynamics and Electric Propulsion Laboratory (PEPL). The main features of the proposed effort were as follows: We Characterized Hall thruster [and arcjet] performance by measuring ion exhaust velocity with probes at various thruster conditions. Used a variety of probe diagnostics in the thruster plume to measure plasma properties and flow properties including T(sub e) and n(sub e), ion current density and ion energy distribution, and electric fields by mapping plasma potential. Used emission spectroscopy to identify species within the plume and to measure electron temperatures.

  7. Terahertz Antiferromagnetic Spin Hall Nano-Oscillator

    NASA Astrophysics Data System (ADS)

    Cheng, Ran; Xiao, Di; Brataas, Arne

    2016-05-01

    We consider the current-induced dynamics of insulating antiferromagnets in a spin Hall geometry. Sufficiently large in-plane currents perpendicular to the Néel order trigger spontaneous oscillations at frequencies between the acoustic and the optical eigenmodes. The direction of the driving current determines the chirality of the excitation. When the current exceeds a threshold, the combined effect of spin pumping and current-induced torques introduces a dynamic feedback that sustains steady-state oscillations with amplitudes controllable via the applied current. The ac voltage output is calculated numerically as a function of the dc current input for different feedback strengths. Our findings open a route towards terahertz antiferromagnetic spin-torque oscillators.

  8. Terahertz Antiferromagnetic Spin Hall Nano-Oscillator.

    PubMed

    Cheng, Ran; Xiao, Di; Brataas, Arne

    2016-05-20

    We consider the current-induced dynamics of insulating antiferromagnets in a spin Hall geometry. Sufficiently large in-plane currents perpendicular to the Néel order trigger spontaneous oscillations at frequencies between the acoustic and the optical eigenmodes. The direction of the driving current determines the chirality of the excitation. When the current exceeds a threshold, the combined effect of spin pumping and current-induced torques introduces a dynamic feedback that sustains steady-state oscillations with amplitudes controllable via the applied current. The ac voltage output is calculated numerically as a function of the dc current input for different feedback strengths. Our findings open a route towards terahertz antiferromagnetic spin-torque oscillators. PMID:27258884

  9. Quantum Numbers of Textured Hall Effect Quasiparticles

    SciTech Connect

    Nayak, C.; Wilczek, F.

    1996-11-01

    We propose a class of variational wave functions with slow variation in spin and charge density and simple vortex structure at infinity, which properly generalize both the Laughlin quasiparticles and baby Skyrmions. We argue, on the basis of these wave functions and a spin-statistics relation in the relevant effective field theory, that the spin of the corresponding quasiparticle has a fractional part related in a universal fashion to the properties of the bulk state. We propose a direct experimental test of this claim. We show that certain spin-singlet quantum Hall states can be understood as arising from primary polarized states by Skyrmion condensation. {copyright} {ital 1996 The American Physical Society.}

  10. Gauge Physics of Spin Hall Effect

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    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.

  11. Magnetic circuit for hall effect plasma accelerator

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    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. Gauge Physics of Spin Hall Effect

    PubMed Central

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

    2015-01-01

    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. PMID:26689260

  13. Stacking order dependence of inverse spin Hall effect and anomalous Hall effect in spin pumping experiments

    SciTech Connect

    Kim, Sang-Il; Seo, Min-Su; Park, Seung-Young; Kim, Dong-Jun; Park, Byong-Guk

    2015-05-07

    The dependence of the measured DC voltage on the non-magnetic material (NM) in NM/CoFeB and CoFeB/NM bilayers is studied under ferromagnetic resonance conditions in a TE{sub 011} resonant cavity. The directional change of the inverse spin Hall effect (ISHE) voltage V{sub ISHE} for the stacking order of the bilayer can separate the pure V{sub ISHE} and the anomalous Hall effect (AHE) voltage V{sub AHE} utilizing the method of addition and subtraction. The Ta and Ti NMs show a broad deviation of the spin Hall angle θ{sub ISH}, which originates from the AHE in accordance with the high resistivity of NMs. However, the Pt and Pd NMs show that the kinds of NMs with low resistivity are consistent with the previously reported θ{sub ISH} values. Therefore, the characteristics that NM should simultaneously satisfy to obtain a reasonable V{sub ISHE} value in bilayer systems are large θ{sub ISH} and low resistivity.

  14. Hall transport of divalent metal ion modified DNA lattices

    SciTech Connect

    Dugasani, Sreekantha Reddy; Lee, Keun Woo; Yoo, Sanghyun; Gnapareddy, Bramaramba; Bashar, Saima; Park, Sung Ha; Kim, Si Joon; Jung, Joohye; Jung, Tae Soo; Kim, Hyun Jae

    2015-06-29

    We investigate the Hall transport characteristics of double-crossover divalent metal ion (Cu{sup 2+}, Ni{sup 2+}, Zn{sup 2+}, and Co{sup 2+})-modified DNA (M-DNA) lattices grown on silica via substrate-assisted growth. The electronic characteristics of the M-DNA lattices are investigated by varying the concentration of the metal ions and then conducting Hall measurements, including resistivity, Hall mobility, carrier concentration, and magneto resistance. The tendency of the resistivity and Hall mobility was to initially decrease as the ion concentration increased, until reaching the saturation concentration (C{sub s}) of each metal ion, and then to increase as the ion concentration increased further. On the other hand, the carrier concentration revealed the opposite tendency as the resistivity and Hall mobility. The specific binding (≤C{sub s}) and the nonspecific aggregates (>C{sub s}) of the ions into the DNA lattices were significantly affected by the Hall characteristics. The numerical ranges of the Hall parameters revealed that the M-DNA lattices with metal ions had semiconductor-like characteristics. Consequently, the distinct characteristics of the electrical transport through M-DNA lattices will provide useful information on the practical use of such structures in physical devices and chemical sensors.

  15. Piezo-Hall coefficients of n-type silicon

    SciTech Connect

    Haelg, B.

    1988-07-01

    The effect of uniaxial mechanical stress on the Hall coefficient of n-type silicon has been measured for various crystallographic orientations, and piezo-Hall coefficients P/sub 12/ and P/sub 11/-P/sub 44/ have been derived for electron concentrations n between 10/sup 14/ and 10/sup 16/ cm/sup -3/ and temperatures ranging from -80 to +100 /sup 0/C. In this range the piezo-Hall effect is found to be as important as the piezoresistance effect which is understood in terms of the many-valley band structure of silicon with anisotropic energy minima. For Hall plates in the (100) and the (110) plane of silicon the resulting longitudinal and transverse piezo-Hall coefficients at room temperature are plotted as a function of their orientation in the plane. It turns out that the piezo-Hall as well as the piezoresistance effects are minimized for a Hall plate in the (110) plane with the current flow roughly parallel to <11-bar1>.

  16. Jerusalem: City of Dreams, City of Sorrows

    ERIC Educational Resources Information Center

    Ricks, Thomas

    2011-01-01

    Jerusalem is more than an intriguing global historical city; it is a classroom for liberal learning and international understanding. It had never been a city of one language, one religion and one culture. Looking at the origins of Jerusalem's name indicates its international and multicultural nature. While Israelis designate Jerusalem as their…

  17. Energy Efficiency Improvements to Wundar Hall, a Historic Building on the Concordia Campus, Milwaukee, Wisconsin

    SciTech Connect

    Karman, Nathan

    2012-11-29

    The Forest County Potawatomi Community (FCPC or Community) implemented energy efficiency improvements to revitalize Wundar Hall, a 34,000 square foot (SF) building that was formerly used as a dormitory and is listed on the National Registry of Historic Places, into an office building. Wundar Hall is the first of many architecturally and historically significant buildings that the Community hopes to renovate at the former Concordia College campus, property on the near west side of Milwaukee that was taken into trust for the Community by the United States on July 10, 1990 (collectively, the Concordia Trust Property). As part of this project, which was conducted with assistance from the Department of Energy's Tribal Energy Program (TEP), the Community updated and/or replaced the building envelope, mechanical systems, the plumbing system, the electrical infrastructure, and building control systems. The project is expected to reduce the building's natural gas consumption by 58% and the electricity consumption by 55%. In addition, the project was designed to act as a catalyst to further renovation of the Concordia Trust Property and the neighborhood. The City of Milwaukee has identified redevelopment of the Concordia Trust Property as a Catalytic Project for revitalizing the near west side. The Tribe envisions a revitalized, mixed-use campus of community services, education, and economic developmen-providing services to the Indian community and jobs to the neighborhood.

  18. What Is Clean Cities?

    SciTech Connect

    Not Available

    2007-08-01

    This Clean Cities Program fact sheet describes the purpose and scope of this DOE program. Clean Cities facilitates the use of alternative and advanced fuels and vehicles to displace petroleum in the transportation sector.

  19. Parametric Investigations of Miniaturized Cylindrical and Annular Hall Thrusters

    SciTech Connect

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

    2001-10-16

    A cylindrical geometry Hall thruster may overcome certain physical and technological limitations in scaling down of Hall thrusters to miniature sizes. The absence of the inner wall and use of the cusp magnetic field can potentially reduce heating of the thruster parts and erosion of the channel. A 2.6 cm miniaturized Hall thruster of a flexible design was built and successfully operated in the power range of 50-300 W. Comparison of preliminary results obtained for cylindrical and annular thruster configurations is presented.

  20. Effective Field Theory of Fractional Quantized Hall Nematics

    SciTech Connect

    Mulligan, Michael; Nayak, Chetan; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC

    2012-06-06

    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.

  1. [250 years ago: the origin of electrotherapy exemplified by Halle].

    PubMed

    Völker, A

    1993-05-01

    Experiments started in 1743 by a working group at the university of Halle marked the beginning of efforts to incorporate electricity into clinical therapy. Very soon this resulted in knowledge that was also taken up elsewhere, leading to a period of intensive research. The creative suggestions that originated in Halle were authored, among others, by Johann Gottlob Krüger, Christian Gottlieb Kratzenstein and Johann Joachim Lange. Their experimental and clinical findings were accompanied by deliberations on the mechanism of action of electrotherapy on which they reported in detail. Due to adverse circumstances this initially leading position occupied by Halle faded out already shortly after the middle of the century. PMID:8517069

  2. Regularity criterion for the 3D Hall-magneto-hydrodynamics

    NASA Astrophysics Data System (ADS)

    Dai, Mimi

    2016-07-01

    This paper studies the regularity problem for the 3D incompressible resistive viscous Hall-magneto-hydrodynamic (Hall-MHD) system. The Kolmogorov 41 phenomenological theory of turbulence [14] predicts that there exists a critical wavenumber above which the high frequency part is dominated by the dissipation term in the fluid equation. Inspired by this idea, we apply an approach of splitting the wavenumber combined with an estimate of the energy flux to obtain a new regularity criterion. The regularity condition presented here is weaker than conditions in the existing criteria (Prodi-Serrin type criteria) for the 3D Hall-MHD system.

  3. Fractional quantum Hall effect in a tilted magnetic field

    NASA Astrophysics Data System (ADS)

    Papić, Z.

    2013-06-01

    We discuss the orbital effect of a tilted magnetic field on the quantum Hall effect in parabolic quantum wells. Many-body states realized at the fractional (1)/(3) and (1)/(2) filling of the second electronic subband are studied using finite-size exact diagonalization. In both cases, we obtain the phase diagram consisting of a fractional quantum Hall fluid phase that persists for moderate tilts, and eventually undergoes a direct transition to the stripe phase. It is shown that tilting of the field probes the geometrical degree of freedom of fractional quantum Hall fluids, and can be partly related to the effect of band-mass anisotropy.

  4. Combinatorial measurements of Hall effect and resistivity in oxide films.

    PubMed

    Clayhold, J A; Kerns, B M; Schroer, M D; Rench, D W; Logvenov, G; Bollinger, A T; Bozovic, I

    2008-03-01

    A system for the simultaneous measurement of the Hall effect in 31 different locations as well as the measurement of the resistivity in 30 different locations on a single oxide thin film grown with a composition gradient is described. Considerations for designing and operating a high-throughput system for characterizing highly conductive oxides with Hall coefficients as small as 10(-10) m3/C are discussed. Results from measurements on films grown using combinatorial molecular beam epitaxy show the usefulness of characterizing combinatorial libraries via both the resistivity and the Hall effect. PMID:18377026

  5. Bosonic Integer Quantum Hall Effect in Optical Flux Lattices

    NASA Astrophysics Data System (ADS)

    Sterdyniak, A.; Cooper, Nigel R.; Regnault, N.

    2015-09-01

    In two dimensions strongly interacting bosons in a magnetic field can realize a bosonic integer quantum Hall state, the simplest two-dimensional example of a symmetry-protected topological phase. We propose a realistic implementation of this phase using an optical flux lattice. Through exact diagonalization calculations, we show that the system exhibits a clear bulk gap and the topological signature of the bosonic integer quantum Hall state. In particular, the calculation of the many-body Chern number leads to a quantized Hall conductance in agreement with the analytical predictions. We also study the stability of the phase with respect to some of the experimentally relevant parameters.

  6. Magnet/Hall-Effect Random-Access Memory

    NASA Technical Reports Server (NTRS)

    Wu, Jiin-Chuan; Stadler, Henry L.; Katti, Romney R.

    1991-01-01

    In proposed magnet/Hall-effect random-access memory (MHRAM), bits of data stored magnetically in Perm-alloy (or equivalent)-film memory elements and read out by using Hall-effect sensors to detect magnetization. Value of each bit represented by polarity of magnetization. Retains data for indefinite time or until data rewritten. Speed of Hall-effect sensors in MHRAM results in readout times of about 100 nanoseconds. Other characteristics include high immunity to ionizing radiation and storage densities of order 10(Sup6)bits/cm(Sup 2) or more.

  7. Is the quantum Hall effect influenced by the gravitational field?

    PubMed

    Hehl, Friedrich W; Obukhov, Yuri N; Rosenow, Bernd

    2004-08-27

    Most of the experiments on the quantum Hall effect (QHE) were made at approximately the same height above sea level. A future international comparison will determine whether the gravitational field g(x) influences the QHE. In the realm of (1+2)-dimensional phenomenological macroscopic electrodynamics, the Ohm-Hall law is metric independent ("topological"). This suggests that it does not couple to g(x). We corroborate this result by a microscopic calculation of the Hall conductance in the presence of a post-Newtonian gravitational field. PMID:15447125

  8. From University Heights to Cooperstown: Halls of Fame and American Memory

    ERIC Educational Resources Information Center

    Friss, Evan J.

    2005-01-01

    This article examines the development and function of American halls of fame as cultural memory institutions. By comparing the Hall of Fame for Great Americans with the National Baseball Hall of Fame, the author posits that halls of fame illuminate the ways in which cultural memory institutions can, through an archival process, preserve, instill,…

  9. CITY III Director's Guide.

    ERIC Educational Resources Information Center

    Envirometrics, Inc., Washington, DC.

    CITY III is a computer-assisted simulation game which allows the participants to make decisions affecting various aspects of the economic, governmental, and social sectors of a simulated urban area. The game director selects one of five possible starting city configurations, may set a number of conditions in the city before the start of play, and…

  10. 14. POWERHOUSE FOREMAN'S BUNGALOW. VIEW OF ENTRY HALL SHOWING STAIRWAY. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. POWERHOUSE FOREMAN'S BUNGALOW. VIEW OF ENTRY HALL SHOWING STAIRWAY. VIEW TO SOUTH-SOUTHEAST. - Thompson Falls Hydroelectric Project, Power Foreman's Bungalow, On island between Forebay Channel & ClarkFord River, Thompson Falls, Sanders County, MT

  11. 18. POWERHOUSE FOREMAN'S BUNGALOW. VIEW FROM REAR OF ENTRANCE HALL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. POWERHOUSE FOREMAN'S BUNGALOW. VIEW FROM REAR OF ENTRANCE HALL TO BEDROOMS. VIEW TO SOUTH-SOUTHEAST. - Thompson Falls Hydroelectric Project, Power Foreman's Bungalow, On island between Forebay Channel & ClarkFord River, Thompson Falls, Sanders County, MT

  12. 48. INTERIOR, FIRST FLOOR, ENTRANCE HALL, DETAIL OF BUST OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    48. INTERIOR, FIRST FLOOR, ENTRANCE HALL, DETAIL OF BUST OF SAMUEL CLEMENTS AND WALL STENCILING - Mark Twain House, 351 Farmington Avenue (corrected from original address of 531 Farmington Avenue), Hartford, Hartford County, CT

  13. Hall Determination of Atomic Radii of Alkali Metals

    ERIC Educational Resources Information Center

    Houari, Ahmed

    2008-01-01

    I will propose here an alternative method for determining atomic radii of alkali metals based on the Hall measurements of their free electron densities and the knowledge of their crystal structure. (Contains 2 figures.)

  14. 14. INTERIOR VIEW OF FIRST FLOOR ENTRY HALL, DOOR TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. INTERIOR VIEW OF FIRST FLOOR ENTRY HALL, DOOR TO LIVING ROOM AND DINING ROOM AT RIGHT, VIEW TO SOUTHEAST, ELECTRONIC FLASH ILLUMINATION. - Le Fevre House, 1444 Moore, Campbell, Santa Clara County, CA

  15. 56. INTERIOR, FIRST FLOOR, WING 1100 EAST, AUDITORIUM (CONFERENCE HALL), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    56. INTERIOR, FIRST FLOOR, WING 1100 EAST, AUDITORIUM (CONFERENCE HALL), REAR AISLE, LEATHER STUDDED DOOR (4' x 5' negative; 8' x 10' print) - U.S. Department of the Interior, Eighteenth & C Streets Northwest, Washington, District of Columbia, DC

  16. 9. FIRST FLOOR, ENTRY HALL, LOOKING SOUTHWEST TOWARDS FRONT ENTRY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. FIRST FLOOR, ENTRY HALL, LOOKING SOUTHWEST TOWARDS FRONT ENTRY WITH OPEN DOORWAY TO WINDER STAIRWAY ON RIGHT - Open Gate Farm, House, Ridge Road, 1 mile East of Elephant Road, Perkasie, Bucks County, PA

  17. 11. Interior view of former mess hall; showing closed doorway ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Interior view of former mess hall; showing closed doorway to former food storage; near northwest corner of building on main floor; view to east. - Ellsworth Air Force Base, Mess & Administration Building, 1561 Ellsworth Street, Blackhawk, Meade County, SD

  18. Survey of the Fermilab D0 detector collision hall

    SciTech Connect

    Babatunde O'Sheg Oshinowo

    2001-07-20

    The Fermilab D0 detector was used for the discovery of the top quark during Run I in 1996. It had been upgraded to exploit the physics potential to be presented by the Main Injector and the Tevatron Collider during Run II. The upgrade of the D0 detector was fully commissioned on March 1, 2001, and thus marked the official start of the Run II experiment. The detector which weighs about 5500 tons, was assembled in the Assembly Hall. Prior to moving the detector into the Collision Hall, the existing survey monuments were densified in the Collision Hall with new monuments. This paper discusses the survey of the Collision Hall using a combination of the Laser Tracker, BETS, V-Stars, and other Optical systems to within the specified accuracy of {+-}0.5mm.

  19. 43. FIRST FLOOR, REAR HALL: REAR HALLWAY BEHIND CURVED STAIRS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    43. FIRST FLOOR, REAR HALL: REAR HALLWAY BEHIND CURVED STAIRS LOOKING NORTH TO 19TH CENTURY ADDITION. Arch defines north wall of original house. - George A. Trenholm Mansion, 172 Rutledge Avenue, Charleston, Charleston County, SC

  20. INTERIOR VIEW OF THE BEDROOM HALL. NOTE THE DOUBLEHUNG WINDOWS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF THE BEDROOM HALL. NOTE THE DOUBLE-HUNG WINDOWS TO THE BEDROOM. VIEW FACING NORTHEAST. - Hickam Field, Fort Kamehameha Officers' Housing Type Z, 19 Worchester Avenue, Honolulu, Honolulu County, HI

  1. Efficient room-temperature Spin Hall nano-oscillator

    NASA Astrophysics Data System (ADS)

    Zholud, Andrei; Urazhdin, Sergei

    2014-03-01

    Spin current injected into a ferromagnet exerts a spin torque on the magnetization, modifying its dynamical damping. Complete compensation of damping by spin current can result in magnetization auto-oscillations, as was demonstrated for in-plane point-contact spin Hall oscillator devices utilizing Pt spin Hall material as a source of spin current and permalloy (Py) as active magnetic layer. Electronic spectroscopy has demonstrated microwave generation by oscillations of magnetization at cryogenic temperatures, but this microwave generation decreases with increasing temperature and disappears at room temperature. We will describe a new device geometry that decouples spin transport from the magnetic configuration by separate patterning of the spin Hall Pt layer and the active Py layer. We demonstrate that this device geometry can operate at smaller driving dc currents for microwave generation that persists up to room temperature. We discuss the physical mechanisms that affect the temperature- and geometry-dependent performance of spin Hall nano-oscillators.

  2. INTERIOR VIEW OF THE SECOND FLOOR STAIR HALL. NOTE THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF THE SECOND FLOOR STAIR HALL. NOTE THE TONGUE-AND-GROOVE WOOD FLOORING AND THE WINDOW ABOVE THE STAIR LANDING. VIEW FACING SOUTH. - Hickam Field, Officers' Housing Type D, 111 Beard Avenue, Honolulu, Honolulu County, HI

  3. 8. 451 MADISON AVENUE, MAIN HALL, SOUTH WALL, MOSAIC TYMPANUM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. 451 MADISON AVENUE, MAIN HALL, SOUTH WALL, MOSAIC TYMPANUM OF THREE FIGURES IN BOLD RELIEF ABOVE FIREPLACE - Villard Houses, 451-457 Madison Avenue & 24 East Fifty-first Street, New York County, NY

  4. 79. DETAIL, MOSAIC FLOOR IN HALL 355 AT ENTRANCE TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    79. DETAIL, MOSAIC FLOOR IN HALL 355 AT ENTRANCE TO REGENTS' ROOM, THIRD FLOOR - Smithsonian Institution Building, 1000 Jefferson Drive, between Ninth & Twelfth Streets, Southwest, Washington, District of Columbia, DC

  5. 27. View east, foreground north facade of Forest Hall, background ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. View east, foreground north facade of Forest Hall, background north facade of Forest East Suites. - Lake Placid Club, Forest Wing, East side of Mirror Lake Drive, North of State Route 86 & Main, North Elba, Essex County, NY

  6. 9. Interior of Building 1009, view of central hall, looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Interior of Building 1009, view of central hall, looking southeast - Naval Air Station Chase Field, Building 1009, Essex Street, .68 mile South-southeast of intersection of Texas State Highway 202 & Independence Street, Beeville, Bee County, TX

  7. INTERIOR VIEW OF HALL. SHOWING THE THREELIGHT EXTERIOR DOOR TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF HALL. SHOWING THE THREE-LIGHT EXTERIOR DOOR TO THE COVERED PATIO AREA AND THE TELEPHONE NICHE. VIEW FACING SOUTHWEST. - Hickam Field, Officers' Housing Type G, 205 Seventh Street, Honolulu, Honolulu County, HI

  8. 8. INTERIOR: FRONT HALL VIEWED FROM LIVING ROOM, SHOWING LIVINGROOM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. INTERIOR: FRONT HALL VIEWED FROM LIVING ROOM, SHOWING LIVING-ROOM COLUMNS, STAIRCASE RAILING AND PANELED SPANDREL, AND NICHE BELOW STAIRCASE, VIEW WEST - Dr. William M. Curtis House, 23-25 High Street, Bristol, Hartford County, CT

  9. Interior view, anteroom of the postmaster general's reception hall; shown ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view, anteroom of the postmaster general's reception hall; shown here are two of the six aluminum statues of postal delivery men - New Post Office Building, Twelfth Street and Pennsylvania Avenue, Washington, District of Columbia, DC

  10. The Design and Fabrication of Bismuth Hall Effect Biosensors

    NASA Astrophysics Data System (ADS)

    Sigillito, A. J.; Rudolph, M.; Soghomonian, V.; Heremans, J. J.

    2011-03-01

    Because of their high sensitivity, accuracy, and low cost, the use of Hall biosensors promises to be an effective diagnostic technique that may aid in the early diagnosis of diseases. In this research, Hall sensors were fabricated from thermally evaporated bismuth thin films. The bismuth films were deposited under high vacuum onto heated Si/ Si O2 substrates using a two layer deposition technique. The films varied in thickness from 60 nm to 75 nm and were etched into Hall bar geometries using photolithography and wet chemical etching. Magnetoresistance and Hall measurements were taken from 4 K to 300 K. The data indicate that the sensors may be characterized using a two carrier model with high mobility, low density holes and low mobility, high density electrons. Additionally, the sensors were exposed to magnetite nanoparticles and characterized using atomic force microscopy. The results will be reported. This research was funded by the National Science Foundation (NSF Grant DMR-0851662).

  11. The Design and Fabrication of Bismuth Hall Effect Biosensors

    NASA Astrophysics Data System (ADS)

    Sigillito, Anthony; Rudolph, Martin; Soghomonian, Vicki; Heremans, J. J.

    2010-10-01

    Because of their high sensitivity, accuracy, and low cost, the use of Hall biosensors promises to be an effective diagnostic technique that may aid in the early diagnosis of diseases. In this research, Hall sensors were fabricated from thermally evaporated bismuth thin films. The bismuth films were deposited under high vacuum onto heated Si/SiO2 substrates using a two layer deposition technique. The films varied in thickness from 60 nm to 75 nm and were etched into Hall bar geometries using photolithography and wet chemical etching. Magnetoresistance and Hall measurements were taken from 4 K to 300 K. The data indicate that the sensors may be characterized using a two carrier model with high mobility, low density holes and low mobility, high density electrons. Additionally, the sensors were exposed to magnetite nanoparticles and characterized using atomic force microscopy. The results will be reported. This research was funded by the National Science Foundation (NSF Grant DMR-0851662).

  12. Interior view, stairwell and entrance to the great hall (note ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view, stairwell and entrance to the great hall (note Boardman Roberts's painting, Great Codifers of Law) - United States Department of Justice, Constitution Avenue between Ninth & Tenth Streets, Northwest, Washington, District of Columbia, DC

  13. 18. VIEW OF STAIRCASE LEADING TO SOCIAL HALL ON CABIN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. VIEW OF STAIRCASE LEADING TO SOCIAL HALL ON CABIN (POOP) DECK, LOCATED IN CENTER OF FORWARD END OF DINING SALOON - Steam Schooner WAPAMA, Kaiser Shipyard No. 3 (Shoal Point), Richmond, Contra Costa County, CA

  14. Linear Magnetization Dependence of the Intrinsic Anomalous Hall Effect

    SciTech Connect

    Zeng, C.; Yao, Y.; Niu, Q.; Weitering, Harm H

    2006-01-01

    The anomalous Hall effect is investigated experimentally and theoretically for ferromagnetic thin films of Mn{sub 5}Ge{sub 3}. We have separated the intrinsic and extrinsic contributions to the experimental anomalous Hall effect and calculated the intrinsic anomalous Hall conductivity from the Berry curvature of the Bloch states using first-principles methods. The intrinsic anomalous Hall conductivity depends linearly on the magnetization, which can be understood from the long-wavelength fluctuations of the spin orientation at finite temperatures. The quantitative agreement between theory and experiment is remarkably good, not only near 0 K but also at finite temperatures, up to about -240 K (0.8T{sub c}).

  15. Batch-fabricated high-performance graphene Hall elements

    PubMed Central

    Xu, Huilong; Zhang, Zhiyong; Shi, Runbo; Liu, Honggang; Wang, Zhenxing; Wang, Sheng; Peng, Lian-Mao

    2013-01-01

    Hall elements are by far the most widely used magnetic sensor. In general, the higher the mobility and the thinner the active region of the semiconductor used, the better the Hall device. While most common magnetic field sensors are Si-based Hall sensors, devices made from III-V compounds tend to favor over that based on Si. However these devices are more expensive and difficult to manufacture than Si, and hard to be integrated with signal-processing circuits for extending function and enforcing performance. In this article we show that graphene is intrinsically an ideal material for Hall elements which may harness the remarkable properties of graphene, i.e. extremely high carrier mobility and atomically thin active body, to create ideal magnetic sensors with high sensitivity, excellent linearity and remarkable thermal stability. PMID:23383375

  16. Residence Halls Unit Agreements: A Step Beyond Rules and Regulations.

    ERIC Educational Resources Information Center

    Scheuermann, Thomas A.; Grandner, Deborah Francis

    1986-01-01

    Discusses the philosophical basis of the Unit Agreement program, provides a description of the Unit Agreement process and how it was developed, and presents the results of a campuswide study of the program's effect on the residence hall environment. (ABB)

  17. 76. TURBINE HALL, UNIT 2 SHOWING BOTH TURBINE AND CONDENSER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    76. TURBINE HALL, UNIT 2 SHOWING BOTH TURBINE AND CONDENSER (SEE ALSO, DRAWING No. 12 OF 13) - Delaware County Electric Company, Chester Station, Delaware River at South end of Ward Street, Chester, Delaware County, PA

  18. 40. VIEW OF TURBINE HALL LOOKING SOUTHWEST AT WESTINGHOUSEPARSONS TURBINE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. VIEW OF TURBINE HALL LOOKING SOUTHWEST AT WESTINGHOUSE-PARSONS TURBINE NUMBER 2. THIS UNIT WAS INSTALLED IN 1925. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

  19. 66. INTERIOR, FIRST FLOOR, WING 1100 EAST, AUDITORIUM (CONFERENCE HALL), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    66. INTERIOR, FIRST FLOOR, WING 1100 EAST, AUDITORIUM (CONFERENCE HALL), DETAIL OF BRONZE GRILL IN BLIND GALLERY - U.S. Department of the Interior, Eighteenth & C Streets Northwest, Washington, District of Columbia, DC

  20. INTERIOR VIEW OF ENTRY HALL. SHOWING THE ORIGINAL ACIDSTAINED CONCRETE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF ENTRY HALL. SHOWING THE ORIGINAL ACID-STAINED CONCRETE FLOOR WITH INCISED STAR PATTERN. VIEW FACING SOUTHEAST. - Hickam Field, Officers' Housing Type C, 208 Second Street, Honolulu, Honolulu County, HI

  1. 154. THIRD FLOOR, STAIR HALL, 300, VIEW TO THE SOUTHEAST, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    154. THIRD FLOOR, STAIR HALL, 300, VIEW TO THE SOUTHEAST, SHOWING DOORS TO EAST (304) AND SOUTH (303) ROOMS, WITH SCALE. - Octagon House, 1799 (1741) New York Avenue, Northwest, Washington, District of Columbia, DC

  2. 32. TURBINE HALL, ORIGINAL TURBO GENERATOR, DETAILS AT CONDENSER, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. TURBINE HALL, ORIGINAL TURBO GENERATOR, DETAILS AT CONDENSER, LOOKING SOUTHEAST - Philadelphia Electric Company, Richmond Power Station, Southeast end of Lewis Street along Delaware River, Philadelphia, Philadelphia County, PA

  3. 31. TURBINE HALL, ORIGINAL TURBO GENERATOR, DETAILS AT CONDENSER, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. TURBINE HALL, ORIGINAL TURBO GENERATOR, DETAILS AT CONDENSER, LOOKING SOUTHEAST - Philadelphia Electric Company, Richmond Power Station, Southeast end of Lewis Street along Delaware River, Philadelphia, Philadelphia County, PA

  4. Interior of the second floor dance hall showing tall and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior of the second floor dance hall showing tall and narrow window openings with 10-foot scale near center, looking south. - Bower Building, 409-413 East Weber Avenue, Stockton, San Joaquin County, CA

  5. 15. SECOND FLOOR, SOUTHWEST ROOM (HALL CHAMBER), SOUTH WALL WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. SECOND FLOOR, SOUTHWEST ROOM (HALL CHAMBER), SOUTH WALL WITH STAIRCASE TO ATTIC AND STAIRWELL FROM FIRST FLOOR - John Richardson House, 15 Race Street, Richardson Park, Wilmington, New Castle County, DE

  6. Enigmatic 12/5 fractional quantum Hall effect

    NASA Astrophysics Data System (ADS)

    Pakrouski, Kiryl; Troyer, Matthias; Wu, Yang-Le; Das Sarma, Sankar; Peterson, Michael R.

    2016-08-01

    We numerically study the fractional quantum Hall effect at filling factors ν =12 /5 and 13/5 (the particle-hole conjugate of 12/5) in high-quality two-dimensional GaAs heterostructures via exact diagonalization including finite well width and Landau-level mixing. We find that Landau-level mixing suppresses the ν =13 /5 fractional quantum Hall effect relative to ν =12 /5 . By contrast, we find both ν =2 /5 and (its particle-hole conjugate) ν =3 /5 fractional quantum Hall effects in the lowest Landau level to be robust under Landau-level mixing and finite well-width corrections. Our results provide a possible explanation for the experimental absence of the 13/5 fractional quantum Hall state as caused by Landau-level mixing effects.

  7. INTERIOR VIEW OF THE HALL, LOOKING TOWARD BEDROOM 3. NOTE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF THE HALL, LOOKING TOWARD BEDROOM 3. NOTE THE TYPICAL BOARD AND BATTEN WALLS AND CEILINGS. VIEW FACING NORTHEAST. - Hickam Field, Fort Kamehameha Officers' Housing Type Y, 27 Worchester Avenue, Honolulu, Honolulu County, HI

  8. INTERIOR; VIEW OF ENTRY HALL, LOOKING SOUTH. Naval Computer ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR; VIEW OF ENTRY HALL, LOOKING SOUTH. - Naval Computer & Telecommunications Area Master Station, Eastern Pacific, Radio Transmitter Facility Lualualei, Marine Barracks, Intersection of Tower Drive & Morse Street, Makaha, Honolulu County, HI

  9. 11. GENERAL VIEW OF MEN'S BATH HALL. Hot Springs ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. GENERAL VIEW OF MEN'S BATH HALL. - Hot Springs National Park, Bathhouse Row, Fordyce Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  10. Life sciences building, north rear, also showing north hall to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Life sciences building, north rear, also showing north hall to the right, and the library in the center distance. - San Bernardino Valley College, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

  11. Basement hall under the northeast part of the building. Live ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Basement hall under the northeast part of the building. Live animal cages and dissection rooms are to the right. Note concrete footings. - San Bernardino Valley College, Life Science Building, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

  12. 21. INTERIOR, DOUBLE STAIRWAY LEADING TO MODEL HALL, DETAIL OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. INTERIOR, DOUBLE STAIRWAY LEADING TO MODEL HALL, DETAIL OF ONE FLIGHT (5 x 7 negative; 8 x 10 print) - Patent Office Building, Bounded by Seventh, Ninth, F & G Streets, Northwest, Washington, District of Columbia, DC

  13. 15. VIEW SHOWING FRONT OF MESS HALL, LOOKING NORTH. STORE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW SHOWING FRONT OF MESS HALL, LOOKING NORTH. STORE WORK WAS SUBSEQUENTLY ADDED Marilyn Ziemer, photographer, April 1988 - Los Pinetos Nike Missile Site, Santa Clara Road, Los Angeles National Forest, Sylmar, Los Angeles County, CA

  14. 18. West room, second floor. View looking southeast. Center hall ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. West room, second floor. View looking southeast. Center hall visible through doorway. - Fort Hill Farm, Mansion, West of Staunton (Roanoke) River between Turkey & Caesar's Runs, Clover, Halifax County, VA

  15. Interior view of entry hall in Communication Center (now Break ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of entry hall in Communication Center (now Break Room and Storage Area), facing north - MacDill Air Force Base, Fire & Guard House, 2709 Florida Keys Avenue, Tampa, Hillsborough County, FL

  16. 16. INDEPENDENCE HALL LOOKING SOUTH ON CHESTNUT ST. (horizontal line) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. INDEPENDENCE HALL LOOKING SOUTH ON CHESTNUT ST. (horizontal line) BETWEEN SIXTH (right) AND FIFTH (left) STS. - Independence National Historical Park, Walnut, Sixth, Chestnut & Second Streets, Philadelphia, Philadelphia County, PA

  17. 20. INTERIOR OF SOUTHERN ROOM. VIEW LOOKING NORTHWEST TOWARD HALL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. INTERIOR OF SOUTHERN ROOM. VIEW LOOKING NORTHWEST TOWARD HALL CONNECTING WITH CENTRAL ROOM. - Chollas Heights Naval Radio Transmitting Facility, Transmitter Building, 6410 Zero Road, San Diego, San Diego County, CA

  18. Superconducting quantum spin Hall systems with giant orbital g factors

    NASA Astrophysics Data System (ADS)

    Reinthaler, R. W.; Tkachov, G.; Hankiewicz, E. M.

    2015-10-01

    Topological aspects of superconductivity in quantum spin Hall systems (QSHSs) such as thin layers of three-dimensional topological insulators (TIs) or two-dimensional TIs are the focus of current research. Here, we describe a superconducting quantum spin Hall effect (quantum spin Hall system in proximity to an s -wave superconductor and in orbital in-plane magnetic fields), which is protected against elastic backscattering by combined time-reversal and particle-hole symmetry. This effect is characterized by spin-polarized edge states, which can be manipulated in weak magnetic fields due to a giant effective orbital g factor, allowing the generation of spin currents. The phenomenon provides a solution to the outstanding challenge of detecting the spin polarization of the edge states. Here we propose the detection of the edge polarization in a three-terminal junction using unusual transport properties of the superconducting quantum Hall effect: a nonmonotonic excess current and a zero-bias conductance peak splitting.

  19. Recent concert halls and opera house in Japan

    NASA Astrophysics Data System (ADS)

    Hidaka, Takayuki

    2001-05-01

    Since we invited Dr. Beranek to Japan for the first time in 1989, we had been working together with him for a period of 13 years, until 2001, on seven hall projects as acoustic design consultants. All of these halls are of premium importance to Japan. Dr. Beranek always came up with innovative concepts and helped create halls endowed with high acoustic originality. These halls are now loved by music-related people and music fanciers and regarded as the pride of Japan. The reviews and studies achieved through these projects were published as seven J. Acoust Soc. Am papers to disclose the outcome in an objective way to the public. A brief outline of the history of our collaboration and its background are presented.

  20. 10. Photocopy of photograph (original in Memorial Hall, Deerfield, Massachusetts) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Photocopy of photograph (original in Memorial Hall, Deerfield, Massachusetts) VIEW OF MAIN ELEVATION, SHOOTING FROM ROAD THROUGH TREES - Kennedy Farm, Chestnut Grove Road, Samples Manor, Washington County, MD

  1. 31. HALL INTERIOR SHOWING SINGLE FRENCH DOOR TO NORTH SIDE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. HALL INTERIOR SHOWING SINGLE FRENCH DOOR TO NORTH SIDE SCREENED PORCH, AND TRAP-DOOR ACCESS TO ATTIC. VIEW TO NORTHEAST. - Big Creek Hydroelectric System, Powerhouse 8, Operator Cottage, Big Creek, Big Creek, Fresno County, CA

  2. DETAIL OF ENTRY HALL AND STAIR ON SOUTH SIDE, VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF ENTRY HALL AND STAIR ON SOUTH SIDE, VIEW FACING NORTH (with scale stick). - Naval Air Station Barbers Point, Telephone Exchange, Coral Sea Road north of Bismarck Sea Road, Ewa, Honolulu County, HI

  3. 1. View looking west, showing side hall facade, wing, porch, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. View looking west, showing side hall facade, wing, porch, setting and garage - First Free Will Baptist Church, Parsonage, South side of Dover Road, corner of Blackhall Road, Epsom, Merrimack County, NH

  4. Electronic Student Response Found Feasible in Large Science Lecture Hall.

    ERIC Educational Resources Information Center

    Shapiro, Joel A.

    1997-01-01

    Describes an inexpensive, homemade student response system that sparks student attention and participation in large lecture halls. Highlights the goals and design of the system as well as its current status and future plans. Contains 15 references. (JRH)

  5. Interior view of main entry hall showing stairs and original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of main entry hall showing stairs and original pipe handrails, facing north. - Albrook Air Force Station, Parachute & Armament Building, 200 feet north of Andrews Boulevard, Balboa, Former Panama Canal Zone, CZ

  6. INTERIOR VIEW OF SECOND FLOOR HALL. SHOWING THE IRON RAILING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF SECOND FLOOR HALL. SHOWING THE IRON RAILING AND DOUBLE FLUSH WOOD DOORS TO THE LINEN CLOSET. VIEW FACING NORTH. - Hickam Field, Officers' Housing Type C, 208 Second Street, Honolulu, Honolulu County, HI

  7. INTERIOR VIEW OF THE HALL. NOTE THE TELEPHONE NICHE, TONGUEANDGROOVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF THE HALL. NOTE THE TELEPHONE NICHE, TONGUE-AND-GROOVE WOOD FLOORING, AND DOUBLE DOOR OF THE LINEN CLOSET. VIEW FACING SOUTHWEST. - Hickam Field, Officers' Housing Type F, 602 Beard Avenue, Honolulu, Honolulu County, HI

  8. Direct Drive Hall Thruster System Development

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    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

  9. Josephson inplane and tunneling currents in bilayer quantum Hall system

    SciTech Connect

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

    2013-12-04

    A Bose-Einstein condensation is formed by composite bosons in the quantum Hall state. A composite boson carries the fundamental charge (–e). We investigate Josephson tunneling of such charges in the bilayer quantum Hall system at the total filling ν = 1. We show the existence of the critical current for the tunneling current to be coherent and dissipationless in tunneling experiments with various geometries.

  10. High-performance LED luminaire for sports hall

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

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

    NASA Technical Reports Server (NTRS)

    Hesterman, Bryce

    2015-01-01

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

  12. Exact solutions of the incompressible dissipative Hall magnetohydrodynamics

    SciTech Connect

    Xia, Zhenwei; Yang, Weihong

    2015-03-15

    By using analytical method, the exact solutions of the incompressible dissipative Hall magnetohydrodynamics (MHD) equations are derived. It is found that a phase difference may occur between the velocity and magnetic field fluctuations when the kinetic and magnetic Reynolds numbers are both very large. Since velocity and magnetic field fluctuations are both circular polarized, the phase difference makes them no longer parallel or anti-parallel like that in the incompressible ideal Hall MHD.

  13. High-frequency Probing Diagnostic for Hall Current Plasma Thrusters

    SciTech Connect

    A.A. Litvak; Y. Raitses; N.J. Fisch

    2001-10-25

    High-frequency oscillations (1-100 MHz) in Hall thrusters have apparently eluded significant experimental scrutiny. A diagnostic setup, consisting of a single Langmuir probe, a special shielded probe connector-positioner, and an electronic impedance-matching circuit, was successfully built and calibrated. Through simultaneous high-frequency probing of the Hall thruster plasma at multiple locations, high-frequency plasma waves have been identified and characterized for various thruster operating conditions.

  14. Nuclear magnetometry studies of spin dynamics in quantum Hall systems

    NASA Astrophysics Data System (ADS)

    Fauzi, M. H.; Watanabe, S.; Hirayama, Y.

    2014-12-01

    We performed a nuclear magnetometry study on quantum Hall ferromagnet with a bilayer total filling factor of νtot=2 . We found not only a rapid nuclear relaxation but also a sudden change in the nuclear-spin polarization distribution after a one-second interaction with a canted antiferromagnetic phase. We discuss the possibility of observing cooperative phenomena coming from nuclear-spin ensemble triggered by hyperfine interaction in quantum Hall system.

  15. A short-orbit spectrometer for Hall C

    SciTech Connect

    Jackson, H.E.; Kowalczyk, R.S.; Potterveld, D.H.; Zeidman, B.; Boudrie, R.L.; Hart, V.E.

    1992-09-01

    A short-orbit spectrometer capable of detecting particles with momentum < 2.0 GeV/c with moderate energy and angular resolution will be available in Hall C for operations in coincidence with the HMS spectrometer or for stand alone operation. The design is based on a QD(-D) configuration which can meet the needs of a broad spectrum of studies appropriate to Hall C. Measurements will be possible for angles of up to 20 degrees out of plane.

  16. A short-orbit spectrometer for Hall C

    SciTech Connect

    Jackson, H.E.; Kowalczyk, R.S.; Potterveld, D.H.; Zeidman, B. ); Boudrie, R.L.; Hart, V.E. )

    1992-01-01

    A short-orbit spectrometer capable of detecting particles with momentum < 2.0 GeV/c with moderate energy and angular resolution will be available in Hall C for operations in coincidence with the HMS spectrometer or for stand alone operation. The design is based on a QD(-D) configuration which can meet the needs of a broad spectrum of studies appropriate to Hall C. Measurements will be possible for angles of up to 20 degrees out of plane.

  17. Spin Charge Separation in the Quantum Spin Hall State

    SciTech Connect

    Qi, Xiao-Liang; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-03-19

    The quantum spin Hall state is a topologically non-trivial insulator state protected by the time reversal symmetry. We show that such a state always leads to spin-charge separation in the presence of a {pi} flux. Our result is generally valid for any interacting system. We present a proposal to experimentally observe the phenomenon of spin-charge separation in the recently discovered quantum spin Hall system.

  18. Quantum Hall effect in bilayer system with array of antidots

    NASA Astrophysics Data System (ADS)

    Pagnossin, I. R.; Gusev, G. M.; Sotomayor, N. M.; Seabra, A. C.; Quivy, A. A.; Lamas, T. E.; Portal, J. C.

    2007-04-01

    We have studied the Quantum Hall effect in a bilayer system modulated by gate-controlled antidot lattice potential. The Hall resistance shows plateaus which are quantized to anomalous multiplies of h/e2. We suggest that this complex behavior is due to the nature of the edge-states in double quantum well (DQW) structures coupled to an array of antidots: these plateaus may be originated from the coexistence of normal and counter-rotating edge-states in different layers.

  19. Topological invariance of the Hall conductance and quantization

    NASA Astrophysics Data System (ADS)

    Bracken, Paul

    2015-08-01

    It is shown that the Kubo equation for the Hall conductance can be expressed as an integral which implies quantization of the Hall conductance. The integral can be interpreted as the first Chern class of a U(1) principal fiber bundle on a two-dimensional torus. This accounts for the conductance given as an integer multiple of e2/h. The formalism can be extended to deduce the fractional conductivity as well.

  20. Linear waves in a resistive plasma with Hall current

    SciTech Connect

    Almaguer, J.A. )

    1992-10-01

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