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Sample records for satellite ring city

  1. Satellite And Propeller Migration In Saturn's Rings

    Science.gov (United States)

    Crida, Aurelien; Charnoz, S.; Papaloizou, J.; Salmon, J.

    2009-09-01

    Saturn's rings host satellites like Pan and Daphnis, and smaller bodies like the recently discovered propellers (Tiscareno et al. 2006). These bodies interact gravitationally with the rings. Actually, the resulting perturbations on the ring system have revealed the presence of embedded objects (the Encke and Keeler gaps associated with Pan and Daphnis respectively, the little two-folded structures called propellers tracing the scattering of ring particles by some embedded small objects). Reciprocally, the rings must act on the embedded bodies, leading to their migration. Here, we study how the standard theory of planetary migration applies in Saturn's ring, where the pressure is negligible in contrast with standard protoplanetary disks. Pan and Daphnis should be in standard type II migration, governed by the global disk evolution. Therefore, their presence and position provide constraints on the history of the A-ring, which can be studied using numerical simulations of disk-satellite interactions. The propellers are fully embedded in the disc, and therefore should be subject to type I migration. The simple impulse approximation used by Lin and Papaloi zou (1979) to derive the one-sided torque is particularly suited to this case. Refining their calculation, taking density variations into account, and discussing the possibility for these bodies to enter the type III, runaway regime of migration, we aim at estimating a possible migration rate for these propellers, to be compared to the system life time.

  2. Saturn's F-ring and inner satellite

    Science.gov (United States)

    1981-01-01

    Saturn's F-ring and its inner shepherding satellite (1980S27) are pictured in this closeup Voyager 2 image acquired Aug. 25 from a range of 365,000 kilometers (227,000 miles). Features as small as 6 km. (3.7 mi.) across are visible. The satellite is elongated and irregular, with its longest axis pointing toward the center of Saturn (toward the upper right in this view). As seen here, the F-ring is thin and does not show the multiple, braided structure Voyager 1 saw last fall. Nor is there any indication of a band or kink in the ring at its closest point to the shepherd; such a feature would be consistent with some of the theories advanced on the formation of the braids. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.

  3. Saturn's Magnetosphere, Rings, and Inner Satellites.

    Science.gov (United States)

    VAN Allen, J A; Thomsen, M F; Randall, B A; Rairden, R L; Grosskreutz, C L

    1980-01-25

    Our 31 August to 5 September 1979 observations together with those of the other Pioneer 11 investigators provide the first credible discovery of the magnetosphere of Saturn and many detailed characteristics thereof. In physical dimensions and energetic charged particle population, Saturn's magnetosphere is intermediate between those of Earth and Jupiter. In terms of planetary radii, the scale of Saturn's magnetosphere more nearly resembles that of Earth and there is much less inflation by entrapped plasma than in the case at Jupiter. The orbit of Titan lies in the outer fringes of the magnetosphere. Particle angular distributions on the inbound leg of the trajectory (sunward side) have a complex pattern but are everywhere consistent with a dipolar magnetic field approximately perpendicular to the planet's equator. On the outbound leg (dawnside) there are marked departures from this situation outside of 7 Saturn radii (Rs), suggesting an equatorial current sheet having both longitudinal and radial components. The particulate rings and inner satellites have a profound effect on the distribution of energetic particles. We find (i) clear absorption signatures of Dione and Mimas; (ii) a broad absorption region encompassing the orbital radii of Tethys and Enceladus but probably attributable, at least in part, to plasma physical effects; (iii) no evidence for Janus (1966 S 1) (S 10) at or near 2.66 Rs; (iv) a satellite of diameter greater, similar 170 kilometers at 2.534 R(s) (1979 S 2), probably the same object as that detected optically by Pioneer 11 (1979 S 1) and previously by groundbased telescopes (1966 S 2) (S 11); (v) a satellite of comparable diameter at 2.343 Rs (1979 S 5); (vi) confirmation of the F ring between 2.336 and 2.371 Rs; (vii) confirmation of the Pioneer division between 2.292 and 2.336 Rs; (viii) a suspected satellite at 2.82 Rs (1979 S 3); (ix) no clear evidence for the E ring though its influence may be obscured by stronger effects; and (x) the

  4. Excitation of inclinations in ring-satellite systems

    Science.gov (United States)

    Borderies, N.; Goldreich, P.; Tremaine, S.

    1984-01-01

    Resonant gravitational interactions between a ring and a satellite produce secular variations of their orbital inclinations. Interactions at vertical resonances, analogous to Lindblad resonances but involving inclinations instead of eccentricities, excite inclinations. There is no inclination analog of the corotation resonance. An equatorial ring changes the inclination of a nearby satellite in qualitatively the same way that a satellite in an equatorial orbit changes the inclination of a nearby ring. Viscous dissipation in a ring leads to an equilibrium value of its inclination. These results provide a basis for discussing the origins of the inclinations of planetary rings.

  5. Tidal disruption of satellites and formation of narrow rings

    CERN Document Server

    Leinhardt, Zoe M; Latter, Henrik N; Kokubo, Eiichiro

    2012-01-01

    In this paper we investigate the formation of narrow planetary rings such as those found around Uranus and Saturn through the tidal disruption of a weak, gravitationally bound satellite that migrates within its Roche limit. Using $N$-body simulations, we study the behaviour of rubble piles placed on circular orbits at different distances from a central planet. We consider both homogeneous satellites and differentiated bodies containing a denser core. We show that the Roche limit for a rubble pile is closer to the planet than for a fluid body of the same mean density. The Roche limit for a differentiated body is also closer to the planet than for a homogeneous satellite of the same mean density. Within its Roche limit, a homogeneous satellite totally disrupts and forms a narrow ring. The initial stages of the disruption are similar to the evolution of a viscous fluid ellipsoid, which can be computed semi-analytically. On the other hand, when a differentiated satellite is just within the Roche limit only the ma...

  6. Keck Adaptive Optics Observations of Neptune's Ring and Satellite Keck Adaptive Optics Observations of Neptune's Ring and Satellite System

    Science.gov (United States)

    de Pater, I.; Gibbard, S.; Martin, S.; Marchis, F.; Roe, H. G.; Macintosh, B.

    2003-05-01

    We observed Neptune, its satellites and ring system on UT 27 and 28 July 2002, with NIRC2 on the 10-m Keck II telescope at 2.2 micron. The total field of view was 10". Each image was integrated for 1 minute; on the first day we had a total of 18 frames, and 33 images on the second day, each spread out over a time interval of 1-2 hours. The complete Adams and Le Verrier rings are visible on each day, after combining all images. In the regions away from the ring arcs, we find that the Le Verrier ring is brighter (up to 20-40%) than the Adams ring. The ring arcs are readily apparent in combinations of the data that take into account Keplerian motion. The ring arc positions are in close agreement with Nicholson et al's (1995) result, as in HST/NICMOS images (Dumas et al. 2002). The Egalite ring has broadened even more since observed with HST/NICMOS in 1998, and is clearly the brightest ring arc. Liberte has decreased in intensity since Voyager and NICMOS. Courage was extremely faint in our images. The satellites Proteus, Larissa, Galatea and Despina are easily seen on individual frames. Thalassa is detected after properly shifting/rotating and adding several frames. This is the first time since the Voyager flybys that Thalassa is detected. Preliminary astrometric measurements suggest the satellites Larissa and Galathea, relative to Proteus, to be off from their nominal (JPL Horizons) positions by 0.3", and Despina by 0.1". Recent results indicate that Proteus is offset by 0.1" compared to Triton (Martins et al. 2003). Preliminary I/F values are 0.06 for Proteus, 0.045 for Larissa and Galatea, and 0.03 for Despina and Thalassa. These observations were supported by the National Science Foundation Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under cooperative agreement No. AST-9876783

  7. Satellite observations of aerosol and CO over Mexico City

    Science.gov (United States)

    Massie, Steven T.; Gille, John C.; Edwards, David P.; Nandi, Sreela

    The development of remote sensing satellite technology potentially will lead to the technical means to monitor air pollution emitted from large cities on a global basis. This paper presents observations by the moderate resolution imaging spectroradiometer (MODIS) and measurements of pollution in the troposphere (MOPITT) experiments of aerosol optical depths and CO mixing ratios, respectively, in the vicinity of Mexico City to illustrate current satellite capabilities. MOPITT CO mixing ratios over Mexico City, averaged between January-March 2002-2005, are 19% above regional values and the CO plume extends over 10° 2 in the free troposphere at 500 hPa. Time series of Red Automatica de Monitoreo Ambiental (RAMA) PM10, and (Aerosol Robotic Network) AERONET and MODIS aerosol optical depths, and RAMA and MOPITT CO time series are inter-compared to illustrate the different perspectives of ground based and satellite instrumentation. Finally, we demonstrate, by examining MODIS and MOPITT data in April 2003, that satellite data can be used to identify episodes in which pollution form fires influences the time series of ground based and satellite observations of urban pollution.

  8. Near-infrared spectrophotometry of the satellites and rings of Uranus

    Science.gov (United States)

    Soifer, B. T.; Neugebauer, G.; Matthews, K.

    1981-01-01

    New spectrophotometry from 1.5 to 2.5 microns is reported for the Uranian satellites Titania, Oberon, and Umbriel. A spectrum of the rings of Uranus from 2.0 to 2.4 microns is also reported. No evidence is found for frost covering the surface of the ring material, consistent with the low albedo of the rings previously reported by Nicholson and Jones (1980). The surfaces of the satellites are found to be covered by dirty water frost. Assuming albedos of the frost and gray components covering the Uranian satellites to be the same as the light and dark faces of Iapetus, radii are derived that are roughly twice those inferred from the assumption of a visual albedo of 0.5.

  9. The formation of Saturn's satellites and rings, as influenced by Saturn's contraction history

    Science.gov (United States)

    Pollack, J. B.; Grossman, A. S.; Moore, R.; Graboske, H. C., Jr.

    1976-01-01

    The paper investigates constraints imposed on the ice content of Saturn's satellites and rings by the planet's high luminosity during the early part of its quasi-equilibrium contraction phase. It is assumed that the addition of ices to the satellites was not completed until after the start of the quasi-equilibrium contraction and that the condensation of ices ceased at the same time within the primordial nebulae of Jupiter and Saturn. Using previously derived limits on the time of condensation cessation for Jupiter's system, the following tentative conclusions are made: (1) Titan is the innermost satellite at whose position a methane-containing ice could condense; (2) water ice could have condensed at the positions of all the satellites; (3) the systematic decrease in the mass of the regular satellites with decreasing distance from the planet may have been caused, in part, by the larger time intervals, for the closer satellites, between the start of contraction and the first condensation of ices at their positions; and (4) ammonia ices, primarily NH4SH, were able to condense at the positions of all but the innermost satellites. It is also shown that water ice could have condensed in the region of the rings near the end of the condensation period.

  10. Satellite data for Singapore, Manila and Kuala Lumpur city growth analysis

    Directory of Open Access Journals (Sweden)

    Mukesh Singh Boori

    2016-06-01

    Full Text Available This data article presents satellite data related to city growth of Singapore, Manila and Kuala Lumpur cities. The data were collected from NASA and USGS websites. A method has been developed for city built-up density from city center to outward till 50 km by using satellite data. These data sets consists three decade Landsat images. A detailed description is given to show how to use this data to produce urban growth maps. The urban growth maps have been used to know the changes and growth pattern in the Southeast Asia Cities.

  11. Satellite data for Singapore, Manila and Kuala Lumpur city growth analysis.

    Science.gov (United States)

    Boori, Mukesh Singh; Choudhary, Komal; Kupriyanov, Alexander; Kovelskiy, Viktor

    2016-06-01

    This data article presents satellite data related to city growth of Singapore, Manila and Kuala Lumpur cities. The data were collected from NASA and USGS websites. A method has been developed for city built-up density from city center to outward till 50 km by using satellite data. These data sets consists three decade Landsat images. A detailed description is given to show how to use this data to produce urban growth maps. The urban growth maps have been used to know the changes and growth pattern in the Southeast Asia Cities.

  12. HST Observations of Saturnian Satellites during the 1995 Ring Plane Crossings

    Science.gov (United States)

    McGhee, Colleen A.; Nicholson, Philip D.; French, Richard G.; Hall, Katherine J.

    2001-08-01

    In May, August, and November 1995, Hubble Space Telescope (HST) observations during Saturn's ring-plane crossings allowed us to view saturnian satellites normally hidden to Earth-based observers in the glare of the rings. New measurements of Janus, Epimetheus, Prometheus, and Pandora have been combined to form revised orbital solutions using all three HST data sets. These measurements and orbit fits are presented, as well as similar fits for the brighter satellites Mimas, Tethys, Enceladus, Dione, and Rhea. Observations of the Lagrangian satellites Telesto, Calypso, and Helene are also reported. While most satellites were found to be close to their expected positions based on previous orbital solutions (Nicholson et al. 1992, Icarus100, 464-484; Jacobson 1996, Bull. Amer. Astron. Soc.28, 1185; and Harper and Taylor 1993, Astron. Astrophys. 268, 326-349). Prometheus lagged behind its predicted longitude by 18.85°±0.04°. A systematic drift in Pandora's longitude of -1.85° relative to the Voyager ephemeris was observed between May and November. The new data on the coorbital satellites Janus and Epimetheus have resulted in a revised mass for Janus, ˜6% smaller than the previous value (Jacobson 1995, Bull. Amer. Astron. Soc.27, 1202). Subtraction of light from the edge-on rings has led to additional detections of objects S/1995-S1 and S3 (Bosh and Rivkin 1995, Science272, 518-521) in the May data, and S/1995-S5, S6, S7 (Nicholson et al. 1995, Bull. Amer. Astron. Soc. 27, 1202) and S/1995-S9 (Roddier et al. 1996) in the August images. S1 is identified with Atlas but leads its predicted position by ˜25°. S3 has an orbit consistent with that of the narrow F ring, but S5, S6, S7, and S9 now appear to orbit ˜530-950 km interior to this ring. S7 and S9 may even be coorbital with Prometheus. An object in the May images, possibly corresponding to S7, is also found to lie very close to Prometheus' orbit (˜800 km interior to the F ring), but no convincing detections of

  13. Near-infrared photometry and astrometry of Neptune's inner satellites and ring-arcs

    Science.gov (United States)

    Dumas, C.; Terrile, R. J.; Smith, B. A.; Schneider, G.; Becklin, E. E.

    2000-10-01

    Until recently, the system of Neptune's inner satellites and ring-arcs had only been observed in direct imaging from the Voyager 2 spacecraft, limiting our knowledge of this system to visible wavelengths data. Nearly ten years after the Voyager fly-by, HST/NICMOS observed the close vicinity of Neptune at 1.87μ m, a wavelength that corresponds to a strong methane absorption in the atmosphere of Neptune and allows the attenuation of the scattered light produced by the planet. We derived the near-infrared geometric albedo of the ring-arcs and small moons Proteus, Larissa, Galatea and Despina, and compared their orbital positions with the predictions from the 1989 Voyager observations. The surfaces of the inner satellites of Neptune appear to be coated with dark, neutral material, with albedoes ranging from 0.077 (Proteus) to 0.033 (Despina) and their orbital position was found to be within the prediction errors of the Voyager measurements. The material located inside the ring-arcs of Neptune also displays a low-neutral reflectance (p{1.87 μm } ~ 0.055) and the HST/NICMOS measurement of the mean orbital motion of the ring-arcs shows that their confinement cannot be entirely explained by resonances produced by the nearby satellite Galatea (Nature, 400, 733-735). This work was performed at the Jet Propulsion Laboratory, Caltech, under contract with the National Aeronautics and Space Administration, and is supported by NASA grant NAG5-3042.

  14. The Copenhagen Traffic Model and its Application in the Metro City Ring Project

    DEFF Research Database (Denmark)

    Vuk, Goran; Overgård, Christian Hansen; Fox, J.

    2009-01-01

    In June 2007, the Danish Parliament passed an act to finance the construction of the Metro City Ring in Copenhagen. The assessment project is based on the passenger patronage forecasts for 2015 from the Copenhagen traffic model. In this paper we show how the model forecasts for this particular...... infrastructure project can be explained through detailed knowledge of model structure and model validation....

  15. A sensitivity analysis of Ring effect to aerosol properties and comparison to satellite observations

    Directory of Open Access Journals (Sweden)

    T. Wagner

    2010-12-01

    Full Text Available In this study we explore the sensitivity of satellite observations of the Ring effect (at various wavelengths to atmospheric aerosol properties. Compared to clouds, aerosols have a rather weak influence on the Ring effect, thus the requirements on the accuracy of the measurements and the radiative transfer simulations are high. In this study, we show that for moderate and high aerosol optical depth (AOD, Ring effect observations are sensitive enough to yield information not only on the AOD, but also on the absorbing properties of aerosols and the aerosol layer height. The latter two quantities are especially important for the determination of the radiative effects of aerosols.

    Our investigations are based on observations by the satellite instrument SCIAMACHY on ENVISAT (2004–2008 and on model simulations using the Monte-Carlo radiative transfer model McArtim. In addition to the Ring effect we investigate the impact of aerosols on the absorptions of the oxygen molecule (O2 and dimer (O4 as well as the radiance. In general good consistency between measured and simulated quantities is found. In some cases also systematic differences occurred, which are probably mainly related to the strong polarisation sensitivity of the SCIAMACHY instrument.

    Our study indicates that Ring effect observations have important advantages for aerosol retrievals: they can be analysed with high accuracy in various wavelength ranges; and depending on the wavelength range, they show different sensitivities on aerosol properties like single scattering albedo, optical depth or layer height. The results of this study are of particular interest for future aerosol inversion algorithms for satellite instruments with reduced polarisation sensitivity and smaller ground pixels, capable of measuring the Ring effect with higher accuracy.

  16. Quantitative measurements of Jupiter, Saturn, their rings and satellites made from Voyager imaging data

    Science.gov (United States)

    Collins, S. A.; Bunker, A. S.

    1983-01-01

    The Voyager spacecraft cameras use selenium-sulfur slow scan vidicons to convert focused optical images into sensible electrical signals. The vidicon-generated data thus obtained are the basis of measurements of much greater precision than was previously possible, in virtue of their superior linearity, geometric fidelity, and the use of in-flight calibration. Attention is given to positional, radiometric, and dynamical measurements conducted on the basis of vidicon data for the Saturn rings, the Saturn satellites, and the Jupiter atmosphere.

  17. Astrometry and Near-Infrared Photometry of Neptune's Inner Satellites and Ring Arcs

    Science.gov (United States)

    Dumas, Christophe; Terrile, Richard J.; Smith, Bradford A.; Schneider, Glenn

    2002-03-01

    We report 1.87 μm photometry and astrometry of the inner satellites (Proteus, Larissa, Galatea, and Despina) and ring arcs of Neptune, obtained with the Hubble Space Telescope and its near-infrared camera NICMOS. From comparison with the Voyager data obtained at visible wavelengths, the small bodies orbiting within the ring region of Neptune have a near-infrared albedo consistently low, but higher than at visible wavelengths for most of the satellites, ranging from p1.87μm=0.058 (Despina) to p1.87μm=0.094 (Proteus). The ring arcs display a reddish spectral response similar to the satellites' in the 0.5-1.9 μm wavelength range. If we consider an earlier photometric measurement of Proteus obtained at K band, the satellite's albedo shows a depression at 2.2 μm that could be the first spectral evidence for the presence of CH or CN bearing material on its surface. Although astrometry of the inner moons of Neptune yields positions consistent with the predictions derived from Voyager images, the long time base between the Voyager and NICMOS observations allows us to refine our knowledge of their mean motions and semimajor axes, and to decrease the errors associated with these measurements. In addition, we confirm a mismatch between the mean semimajor axis of the ring arcs and the location of the 42:43 corotation inclined resonance due to Galatea. This result calls into question the ability of this resonance to confine the arcs azimuthally.

  18. Radial diffusion in Saturn's radiation belts - A modeling analysis assuming satellite and ring E absorption

    Science.gov (United States)

    Hood, L. L.

    1983-01-01

    A modeling analysis is carried out of six experimental phase space density profiles for nearly equatorially mirroring protons using methods based on the approach of Thomsen et al. (1977). The form of the time-averaged radial diffusion coefficient D(L) that gives an optimal fit to the experimental profiles is determined under the assumption that simple satellite plus Ring E absorption of inwardly diffusing particles and steady-state radial diffusion are the dominant physical processes affecting the proton data in the L range that is modeled. An extension of the single-satellite model employed by Thomsen et al. to a model that includes multisatellite and ring absorption is described, and the procedures adopted for estimating characteristic satellite and ring absorption times are defined. The results obtained in applying three representative solid-body absorption models to evaluate D(L) in the range where L is between 4 and 16 are reported, and a study is made of the sensitivity of the preferred amplitude and L dependence for D(L) to the assumed model parameters. The inferred form of D(L) is then compared with that which would be predicted if various proposed physical mechanisms for driving magnetospheric radial diffusion are operative at Saturn.

  19. Using Satellite Images for Wireless Network Planing in Baku City

    Science.gov (United States)

    Gojamanov, M.; Ismayilov, J.

    2013-04-01

    It is a well known fact that the Information-Telecommunication and Space research technologies are the fields getting much more benefits from the achievements of the scientific and technical progress. In many cases, these areas supporting each other have improved the conditions for their further development. For instance, the intensive development in the field of the mobile communication has caused the rapid progress of the Space research technologies and vice versa.Today it is impossible to solve one of the most important tasks of the mobile communication as Radio Frecance planning without the 2D and 3D digital maps. The compiling of such maps is much more efficient by means of the space images. Because the quality of the space images has been improved and developed, especially at the both spectral and spatial resolution points. It has been possible to to use 8 Band images with the spatial resolution of 50 sm. At present, in relation to the function 3G of mobile communications one of the main issues facing mobile operator companies is a high-precision 3D digital maps. It should be noted that the number of mobile phone users in the Republic of Azerbaijan went forward other Community of Independent States Countries. Of course, using of aerial images for 3D mapping would be optimal. However, depending on a number of technical and administrative problems aerial photography cannot be used. Therefore, the experience of many countries shows that it will be more effective to use the space images with the higher resolution for these issues. Concerning the fact that the mobile communication within the city of Baku has included 3G function there were ordered stereo images wih the spatial resolution of 50 cm for the 150 sq.km territory occupying the central part of the city in order to compile 3D digital maps. The images collected from the WorldView-2 satellite are 4-Band Bundle(Pan+MS1) stereo images. Such kind of imagery enable to automatically classificate some required

  20. The Spectral Classes of the Saturnian System Ices: Rings and Satellites Observations by Cassini-VIMS

    Science.gov (United States)

    Filacchione, G.; Capaccioni, F.; Tosi, F.; Coradini, A.; Cerroni, P.; Clark, R. N.; Cuzzi, J. N.; Nicholson, P. D.; Buratti, B. J.; Brown, R. H.; Cruikshank, D. P.; Jaumann, R.; Hedman, M. M.

    2008-12-01

    The entire population of the Saturnian system ices was investigated by VIMS (Visual and Infrared Mapping Spectrometer) experiment on board Cassini spacecraft. By the end of the nominal mission a very large dataset of hyperspectral data had been collected in the spectral range 0.35-5.0 micron, which includes the regular satellites (Mimas, Enceladus, Tethys, Dione, Rhea, Hyperion, Iapetus, Phoebe), minor moons (Atlas, Prometheus, Pandora, Janus, Epimetheus, Telesto, Calypso) and rings. In this work we present an analysis of spectrophotometric indicators selected to describe the properties of the ices (I/F continuum levels, visible spectral slopes, band depths and positions), and which were retrieved from about 1500 full-disk observations of satellites as well as from mosaics of the main rings (A, B, C, CD, F) sampled with a resolution of 125 km/pixel along the radial axis. This comparative method allows us to highlight the spectral differences in this population of objects orbiting in the Saturnian system. In particular we have retrieved the distribution of the water ice abundance, which varies between the almost pure icy surfaces of Enceladus and Calypso to the carbon dioxide- and organic-rich Hyperion, Iapetus and Phoebe. Noteworthy is that a significant dichotomy is observed between the two co-orbital moons Epimetheus and Janus, possibly indicating a different origin and evolutionary process: while the first shows a very red visible spectrum (similar to Hyperion), the second has more neutral visible colors, making it a very peculiar object in the Saturnian system. Rings have very peculiar spectral differences when compared with the icy satellites: in the visible range their spectra are characterized by a spectral knee at bluer wavelengths (at about 520 nm compared to 550 nm on satellites); in the infrared range the 1.5-2.0 micron water ice band depths are in general deeper across the A and B rings, indicative of a larger fraction of pure water ice in comparison to

  1. Precision Navigation of Cassini Images Using Rings, Icy Satellites, and Fuzzy Bodies

    Science.gov (United States)

    French, Robert S.; Showalter, Mark R.; Gordon, Mitchell K.

    2016-10-01

    Before images from the Cassini spacecraft can be analyzed, errors in the published pointing information (up to ~110 pixels for the Imaging Science Subsystem Narrow Angle Camera) must be corrected so that the line of sight vector for each pixel is known. This complicated and labor-intensive process involves matching the image contents with known features such as stars, rings, or moons. Metadata, such as lighting geometry or ring radius and longitude, must be computed for each pixel as well. Both steps require mastering the SPICE toolkit, a highly capable piece of software with a steep learning curve. Only after these steps are completed can the actual scientific investigation begin.We have embarked on a three-year project to perform these steps for all 400,000+ Cassini ISS images as well as images taken by the VIMS, UVIS, and CIRS instruments. The result will be a series of SPICE kernels that include accurate pointing information and a series of backplanes that include precomputed metadata for each pixel. All data will be made public through the PDS Ring-Moon Systems Node (http://www.pds-rings.seti.org). We expect this project to dramatically decrease the time required for scientists to analyze Cassini data.In a previous poster (French et al. 2014, DPS #46, 422.01) we discussed our progress navigating images using stars, simple ring models, and well-defined icy bodies. In this poster we will report on our current progress including the use of more sophisticated ring models, navigation of "fuzzy" bodies such as Titan and Saturn, and use of crater matching on high-resolution images of the icy satellites.

  2. Saturnian trapped radiation and its absorption by satellites and rings: the first results from pioneer 11.

    Science.gov (United States)

    Simpson, J A; Bastian, T S; Chenette, D L; Lentz, G A; McKibben, R B; Pyle, K R; Tuzzolino, A J

    1980-01-25

    Electrons and protons accelerated and trapped in a Saturnian magnetic field have been found by the University of Chicago experiments on Pioneer 11 within 20 Saturn radii (Rs) of the planet. In the innermost regions, strong absorption effects due to satellites and ring material were observed, and from approximately 4 Rs inwards to the outer edge of the A ring at 2.30 Rs (where the radiation is absorbed), the intensity distributions of protons (>/= 0.5 million electron volts) and electrons (2 to 20 million electron volts) were axially symmetric, consistent with a centered dipole aligned with the planetary rotation axis. The maximum fluxes observed for protons (> 35 million electron volts and for electrons flux increases observed between absorption features raise new questions concerning the physics of charged particle transport and acceleration. An absorption feature near 2.5 Rs has led to the discovery of a previously unknown satellite with a diameter of approximately 200 kilometers, semimajor axis of 2.51 Rs, and eccentricity of 0.013. Radiation absorption features that suggest a nonuniform distribution of matter around Saturn have also been found from 2.34 to 2.36 Rs, near the position of the F ring discovered by the Pioneer imaging experiment. Beneath the A, B, and C rings we continued to observe a low flux of high-energy electrons. We conclude that the inner Saturn magnetosphere, because of its near-axial symmetry and the many discrete radiation absorption regions, offers a unique opportunity to study the acceleration and transport of charged particles in a planetary magnetic field.

  3. Demonstrative potential of multitemporal satellite imagery in documenting urban dynamics: generalisation from the Bucharest city case

    Science.gov (United States)

    Aldea, Mihaela; Petrescu, Florian; Parlow, Eberhard; Iacoboaea, Cristina; Luca, Oana; Sercaianu, Mihai; Gaman, Florian

    2016-08-01

    The main objective of this paper is to demonstrate the potential of multitemporal satellite imagery to be processed and used in documenting urban changes that took place over time, with limited resources involved and taking advantage of the opportunity to be able to use the satellite imagery available as open data. The possibilities to analyse and compare the written literature regarding the chronological evolution of a city with the patterns of Land Use/Land Cover obtained from the processing of satellite remotely sensed images of the respective scenery were investigated based upon a case study of a selected city. The extent of the prospects of using remote sensing based methods and multitemporal satellite imagery is also expressed as a result of this investigation.

  4. Civic Mobilization for School Reform in Rivergrove, Florida: Contesting the "Social Construction of Place" in an Inner Ring Suburban City

    Science.gov (United States)

    Shircliffe, Barbara J.; Lance Rowland, M.

    2015-01-01

    This paper examines civic mobilization for school improvement in Rivergrove, a small suburban city within the inner rings of a large Florida metro (All names of individuals, schools, organizations and communities are pseudonyms per IRB agreement with district. Subsequently, references to local media reports and city documents are disguised to meet…

  5. Geospatial Information from Satellite Imagery for Geovisualisation of Smart Cities in India

    Science.gov (United States)

    Mohan, M.

    2016-06-01

    In the recent past, there have been large emphasis on extraction of geospatial information from satellite imagery. The Geospatial information are being processed through geospatial technologies which are playing important roles in developing of smart cities, particularly in developing countries of the world like India. The study is based on the latest geospatial satellite imagery available for the multi-date, multi-stage, multi-sensor, and multi-resolution. In addition to this, the latest geospatial technologies have been used for digital image processing of remote sensing satellite imagery and the latest geographic information systems as 3-D GeoVisualisation, geospatial digital mapping and geospatial analysis for developing of smart cities in India. The Geospatial information obtained from RS and GPS systems have complex structure involving space, time and presentation. Such information helps in 3-Dimensional digital modelling for smart cities which involves of spatial and non-spatial information integration for geographic visualisation of smart cites in context to the real world. In other words, the geospatial database provides platform for the information visualisation which is also known as geovisualisation. So, as a result there have been an increasing research interest which are being directed to geospatial analysis, digital mapping, geovisualisation, monitoring and developing of smart cities using geospatial technologies. However, the present research has made an attempt for development of cities in real world scenario particulary to help local, regional and state level planners and policy makers to better understand and address issues attributed to cities using the geospatial information from satellite imagery for geovisualisation of Smart Cities in emerging and developing country, India.

  6. GEOSPATIAL INFORMATION FROM SATELLITE IMAGERY FOR GEOVISUALISATION OF SMART CITIES IN INDIA

    Directory of Open Access Journals (Sweden)

    M. Mohan

    2016-06-01

    Full Text Available In the recent past, there have been large emphasis on extraction of geospatial information from satellite imagery. The Geospatial information are being processed through geospatial technologies which are playing important roles in developing of smart cities, particularly in developing countries of the world like India. The study is based on the latest geospatial satellite imagery available for the multi-date, multi-stage, multi-sensor, and multi-resolution. In addition to this, the latest geospatial technologies have been used for digital image processing of remote sensing satellite imagery and the latest geographic information systems as 3-D GeoVisualisation, geospatial digital mapping and geospatial analysis for developing of smart cities in India. The Geospatial information obtained from RS and GPS systems have complex structure involving space, time and presentation. Such information helps in 3-Dimensional digital modelling for smart cities which involves of spatial and non-spatial information integration for geographic visualisation of smart cites in context to the real world. In other words, the geospatial database provides platform for the information visualisation which is also known as geovisualisation. So, as a result there have been an increasing research interest which are being directed to geospatial analysis, digital mapping, geovisualisation, monitoring and developing of smart cities using geospatial technologies. However, the present research has made an attempt for development of cities in real world scenario particulary to help local, regional and state level planners and policy makers to better understand and address issues attributed to cities using the geospatial information from satellite imagery for geovisualisation of Smart Cities in emerging and developing country, India.

  7. Hazing Iran: Satellite Imagery, Human Rights, and City as Camp

    OpenAIRE

    Zhang, Amy

    2014-01-01

    As perhaps most obviously evidenced in the political maneuverings that led up to the second Gulf War in 2003, the use of satellite imagery to document spatial terrain is often, and almost instantly, politicized. In the two images presented here, this politicization takes on a two-way relationship and is open to contrasting and inevitably dualistic readings. One way of describing their relationship is as "Target" and "Aftermath". On the left, we have an image of the nuclear plant near the Iran...

  8. Multiplatform sampling (ship, aircraft, and satellite) of a Gulf Stream warm core ring

    Science.gov (United States)

    Smith, Raymond C.; Brown, Otis B.; Hoge, Frank E.; Baker, Karen S.; Evans, Robert H.

    1987-01-01

    The purpose of this paper is to demonstrate the ability to meet the need to measure distributions of physical and biological properties of the ocean over large areas synoptically and over long time periods by means of remote sensing utilizing contemporaneous buoy, ship, aircraft, and satellite (i.e., multiplatform) sampling strategies. A mapping of sea surface temperature and chlorophyll fields in a Gulf Stream warm core ring using the multiplatform approach is described. Sampling capabilities of each sensing system are discussed as background for the data collected by means of these three dissimilar methods. Commensurate space/time sample sets from each sensing system are compared, and their relative accuracies in space and time are determined. The three-dimensional composite maps derived from the data set provide a synoptic perspective unobtainable from single platforms alone.

  9. A Comparative Analysis of the Far Infrared Spectra of Saturn's Rings and Icy Satellites with Cassini CIRS

    Science.gov (United States)

    Brooks, Shawn M.; Spilker, Linda; Edgington, Scott G.

    2016-10-01

    We will report on a campaign to observe Saturn's main rings and major icy satellites with the Composite Infrared Spectrometer onboard Cassini. CIRS' three infrared detectors cover a combined spectral range of 10 to 1400 cm-1 (1 mm down to 7 microns). We focus on data from Focal Plane 1, which covers the 10 to 600 cm-1 range (1 mm to 16 microns). The apodized spectral resolution of the instrument can be varied from 15 cm-1 to 0.5 cm-1 (Flasar et al. 2004).The spectral behavior of Saturn's main rings and icy satellites in the far infrared has been the subject of previous studies with CIRS FP1 data (Spilker at al. 2005, Carvano et al. 2007, Morishima et al. 2012). These studies have shown that the infrared spectra of these icy rings and bodies are remarkably flat between about 40 to 200 microns. Longward of this, CIRS observations, as well as older spacecraft data, show a gradual decrease in ring emissivity. This roll-off in emissivity may be due to varying optical constants of water ice, which dominates the rings' composition, as one moves towards microwave wavelengths. Carvano et al. (2007), who analyzed spectra of the icy satellites Phoebe, Iapetus, Enceladus, Tethys and Hyperion, investigated the absence of emissivity features in spectra of those satellites. This absence is intriguing, as water ice, which dominates their surface composition, contains absorption features in the FP1 spectral range. They conclude that high porosity in these satellites' regoliths may explain this lack of spectral variability.To better characterize the far infrared spectra of the rings and satellites, we have implemented a series of dedicated observations. The goal is to obtain thousands of infrared spectra at 3 cm-1 resolution of each individual ring region and as many satellites as possible. We will have more spectra than Spilker et al. had for their work at a higher spectral resolution than in the analyses of Carvano et al. and Morishima et al. A preliminary analysis of these

  10. SPEED COMPLIANCE IN FREEWAY VARIABLE SPEED LIMIT SYSTEM – CASE STUDY OF THE PRAGUE CITY RING

    Directory of Open Access Journals (Sweden)

    Michał MATOWICKI

    2016-03-01

    Full Text Available Many previous studies have confirmed the strong relationship between speed compliance and the frequency and severity of traffic accidents. Variable speed limit (VSL system as a measure to improve traffic safety enables the freeway system to change its posted speed limit based on various traffic and environmental conditions. Such system helps drivers to recognize the upcoming events, to adjust their driving style and in such way to address speed variation of the traffic flow. This is called speed harmonization. Although many studies researching the effect of VSL system on the traffic stream can be found, there are only few addressing its influence on the drivers behavior, particularly focusing on their tolerance limit and compliance, which has crucial meaning for future design of controlling algorithms. This study was prepared to inspect this grey area by studying the data from the VSL system at Prague city ring, describing the influence of the highway management system and its influence on drivers.

  11. Novel DC ring topology and protection system - a comprehensive solution for mega city power grids

    Science.gov (United States)

    Haj-Maharsi, Mohamed Yassine

    2009-07-01

    The development of mega cities leads to increased load concentration and brings additional challenges to managing the electrical grid while keeping power available for critical loads. Techniques using FACTS devices are being applied to alleviate power management difficulties and to confine faults in their originating areas in order to limit the risk of cascading failures in the grid. The addition of many FACTS devices often results in control and protection coordination difficulties, power oscillations between connected networks, subsynchronous resonance problems, and torsional interactions with nearby generator units. The most effective solution is obtained when the individual AC subsystems representing sources and loads are decoupled so a fault in a given subsystem is not propagated to another subsystem. This solution can be achieved by the deployment of a DC system where power sources and loads are connected to the DC bus through voltage source converters. For a mega city, this would be conceived as a DC ring feeding multiple loads and connected to remote and local power sources. Unfortunately, the lack of fast DC circuit breakers has been one of the key issues affecting extensive applications of DC systems with common DC buses; a DC fault would discharge all the capacitors of the DC bus and cause delays in system recovery and possibly a wide system collapse. In this research, I provide a comprehensive solution to mega city power grid problems by proposing a DC system topology that enables grid expansions without affecting existing protection settings or changing existing AC breaker ratings. I also propose the means for protecting the DC system by designing a fast DC breaker and developing a control algorithm capable of isolating DC faults without blocking converter stations or depleting DC bus capacitors. My contribution is three folds: (1) I modeled and simulated Shanghai power grid and performed a study to identify short circuit and voltage stability problems

  12. Air quality estimates in Mediterranean cities using high resolution satellite technologies

    Science.gov (United States)

    Chudnovsky, Alexandra; Lyapustin, Alexei; Wang, Yujie

    2016-04-01

    Satellite imaging is an essential tool for monitoring air pollution because, unlike ground observations, it supplies continuous data with global coverage of terrestrial and atmospheric components. Satellite-based Aerosol Optical Depth (AOD) retrievals reflect particle abundance in the atmospheric column. This data provide some indication on the extent of particle concentrations. However, it is difficult to retrieve AOD at high spatial resolution above areas with high surface reflectance and heterogeneous land cover, such as urban areas. Therefore, many crowded regions worldwide including Israel, AOD climatology are still uncertain because of the high ground reflectance and coarse spatial resolution. Recently, a new Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm was developed for MODIS which provides AOD at 1 km resolution. This study aims to investigate the spatial variability of AOD within Israeli and several other Mediterranean cities. In addition, we aim to characterize the impact of climatic condition on pollution patterns in-and-between cities and to identify days when cities exhibit the highest variability in AOD. Furthermore, we assessed the differences in pollution levels between adjacent locations. We will report on spatial variability in AOD levels derived from high 1km resolution MAIAC AOD algorithm on a temporal basis, in relation to season and synoptic-meteorological conditions.

  13. OMI NO2 column densities over North American urban cities: the effect of satellite footprint resolution

    Directory of Open Access Journals (Sweden)

    H. C. Kim

    2015-10-01

    Full Text Available Nitrogen dioxide vertical column density (NO2 VCD measurements via satellite are compared with a fine-scale regional chemistry transport model, using a new approach that considers varying satellite footprint sizes. Space-borne NO2 VCD measurement has been used as a proxy for surface nitrogen oxide (NOx emission, especially for anthropogenic urban emission, so accurate comparison of satellite and modeled NO2 VCD is important in determining the future direction of NOx emission policy. The National Aeronautics and Space Administration Ozone Monitoring Instrument (OMI NO2 VCD measurements, retrieved by the Royal Netherlands Meteorological Institute (KNMI, are compared with a 12 km Community Multi-scale Air Quality (CMAQ simulation from the National Oceanic and Atmospheric Administration. We found that OMI footprint pixel sizes are too coarse to resolve urban NO2 plumes, resulting in a possible underestimation in the urban core and overestimation outside. In order to quantify this effect of resolution geometry, we have made two estimates. First, we constructed pseudo-OMI data using fine-scale outputs of the model simulation. Assuming the fine-scale model output is a true measurement, we then collected real OMI footprint coverages and performed conservative spatial regridding to generate a set of fake OMI pixels out of fine-scale model outputs. When compared to the original data, the pseudo-OMI data clearly showed smoothed signals over urban locations, resulting in roughly 20–30 % underestimation over major cities. Second, we further conducted conservative downscaling of OMI NO2 VCD using spatial information from the fine-scale model to adjust the spatial distribution, and also applied Averaging Kernel (AK information to adjust the vertical structure. Four-way comparisons were conducted between OMI with and without downscaling and CMAQ with and without AK information. Results show that OMI and CMAQ NO2 VCDs show the best agreement when both

  14. OMI NO2 column densities over North American urban cities: the effect of satellite footprint resolution

    Science.gov (United States)

    Kim, Hyun Cheol; Lee, Pius; Judd, Laura; Pan, Li; Lefer, Barry

    2016-03-01

    Nitrogen dioxide vertical column density (NO2 VCD) measurements via satellite are compared with a fine-scale regional chemistry transport model, using a new approach that considers varying satellite footprint sizes. Space-borne NO2 VCD measurement has been used as a proxy for surface nitrogen oxide (NOx) emission, especially for anthropogenic urban emission, so accurate comparison of satellite and modeled NO2 VCD is important in determining the future direction of NOx emission policy. The NASA Ozone Monitoring Instrument (OMI) NO2 VCD measurements, retrieved by the Royal Netherlands Meteorological Institute (KNMI), are compared with a 12 km Community Multi-scale Air Quality (CMAQ) simulation from the National Oceanic and Atmospheric Administration. We found that the OMI footprint-pixel sizes are too coarse to resolve urban NO2 plumes, resulting in a possible underestimation in the urban core and overestimation outside. In order to quantify this effect of resolution geometry, we have made two estimates. First, we constructed pseudo-OMI data using fine-scale outputs of the model simulation. Assuming the fine-scale model output is a true measurement, we then collected real OMI footprint coverages and performed conservative spatial regridding to generate a set of fake OMI pixels out of fine-scale model outputs. When compared to the original data, the pseudo-OMI data clearly showed smoothed signals over urban locations, resulting in roughly 20-30 % underestimation over major cities. Second, we further conducted conservative downscaling of OMI NO2 VCDs using spatial information from the fine-scale model to adjust the spatial distribution, and also applied averaging kernel (AK) information to adjust the vertical structure. Four-way comparisons were conducted between OMI with and without downscaling and CMAQ with and without AK information. Results show that OMI and CMAQ NO2 VCDs show the best agreement when both downscaling and AK methods are applied, with the correlation

  15. Satellite remote sensing for urban growth assessment in Shaoxing City, Zhejiang Province

    Institute of Scientific and Technical Information of China (English)

    RAMADAN Elnazir; FENG Xue-zhi (冯学智); CHENG Zheng (程征)

    2004-01-01

    Urban growth represents specific response to economic, demographic and environmental conditions. Rapid urbanization and industrializations have resulted in sharp land cover changes. The present investigation was carried out from Shaoxing City to quantify satellite-derived estimates of urban growth using a three-epoch time series Landsat TM data for the years 1984, 1997 and ETM 2000. The methodology used was based on post classification comparison. The use of GIS allowed spatial analysis of the data derived from remotely sensed images. Results showed that the built-up area surrounding Shaoxing City has expanded at an annual average of 7 km2. Analysis of the classified map showed that the physical growth of urban area is upsetting the other land cover classes such as farming, water resources, etc. The study conclusion mainly emphasized the need for sustainable urban capacity.

  16. The orbits of the uranian satellites and rings, the gravity field of the uranian system, and the orientation of the pole of Uranus

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, R. A., E-mail: robert.jacobson@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States)

    2014-11-01

    French et al. determined the orbits of the Uranian rings, the orientation of the pole of Uranus, and the gravity harmonics of Uranus from Earth-based and Voyager ring occultations. Jacobson et al. determined the orbits of the Uranian satellites and the masses of Uranus and its satellites from Earth-based astrometry and observations acquired with the Voyager 2 spacecraft; they used the gravity harmonics and pole from French et al. Jacobson and Rush reconstructed the Voyager 2 trajectory and redetermined the Uranian system gravity parameters, satellite orbits, and ring orbits in a combined analysis of the data used previously augmented with additional Earth-based astrometry. Here we report on an extension of that work that incorporates additional astrometry and ring occultations together with improved data processing techniques.

  17. Increase in platinum group elements in Mexico City as revealed from growth rings of Taxodium mucronatum ten.

    Science.gov (United States)

    Morton-Bermea, Ofelia; Beramendi-Orosco, Laura; Martínez-Reyes, Ángeles; Hernández-Álvarez, Elizabeth; González-Hernández, Galia

    2016-02-01

    Tree rings may be used as indicators of contamination events providing information on the chronology and the elemental composition of the contamination. In this framework, we report PGEs enrichment in growth rings of Taxodium mucronatum ten for trees growing in the central area of Mexico City as compared to trees growing in a non-urban environment. Concentrations of PGE were determined by ICP-MS analysis on microwave-digested tree rings. The element found in higher concentrations was Pd (1.13-87.98 μg kg(-1)), followed by Rh (0.28-36.81 μg kg(-1)) and Pt (0.106-7.21 μg kg(-1)). The concentration trends of PGEs in the tree-ring sequences from the urban area presented significant correlation values when comparing between trees (r between 0.618 and 0.98, P < 0.025) and between elements within individual trees (r between 0.76 and 0.994, P < 0.01). Furthermore, a clear increase was observed for rings after 1997, with enrichment of up to 60 times the mean concentration found for the sequence from the non-urban area and up to 40 times the mean concentration for the pre-1991 period in the urban trees. These results also demonstrate the feasibility of applying T. mucronatum ten to be used as a bioindicator of the increase in PGE in urban environments.

  18. Monitoring carbon monoxide pollution over the largest ten cities in the US using satellite observations

    Science.gov (United States)

    Zheng, B.; de Beurs, K.; Owsley, B.; Krehbiel, C. P.; Henebry, G. M.

    2015-12-01

    Carbon monoxide (CO) is one of the several air pollutants that are largely produced by anthropogenic activities in urban areas as a result of incomplete combustion of carbon-containing fuels. Long-term satellite data can monitor spatial and temporal changes in CO globally. Here we investigated spatial, vertical, and temporal changes in CO concentrations over the largest ten US metropolitan statistical areas (MSAs) using Version 6 MOPITT TIR-only CO retrievals. The 15-year average of MOPITT Surface CO concentrations over urban areas were highest (388 ppbv) over New York City and lowest (151 ppbv) over Miami. The influence of cities on elevated CO levels extends well beyond the immediate urban area. The CO seasonal profiles above the surface show distinct seasonality with peaks March-April and troughs September-October. However, larger cities show a lack of CO seasonality near the surface. We applied the nonparametric Seasonal Kendall (SK) trend test to the CO time series. Results revealed significant decreasing trends in CO concentration, with stronger trends in the lower atmosphere (>700 hPa) than in the mid-troposphere (500-700 hPa). Our results demonstrate the strong influence of local urban emissions on (near-) surface CO concentrations. Decreasing urban CO over the past 15 years reflects improved urban metabolism through improved energy efficiency, and increasing use of alternative transportation and zero-emission vehicles.

  19. Methanol-CO correlations in Mexico City pollution outflow from aircraft and satellite during MILAGRO

    Directory of Open Access Journals (Sweden)

    Y. Xiao

    2012-02-01

    Full Text Available The correlation between methanol (CH3OH and carbon monoxide (CO is of particular interest for characterizing biogenic and anthropogenic emission sources of CH3OH and other chemical species. Here, the CH3OH/CO enhancement ratio (ΔCH3OH/ΔCO in the lower to middle troposphere is examined using coincident CH3OH and CO observations from aircraft (NCAR C-130 and NASA DC-8 and from the Tropospheric Emission Spectrometer (TES satellite during the MegaCity Initiative: Local and Global Research Observations (MILAGRO in the Mexico City region in March 2006. ΔCH3OH/ΔCO ratios from the two in-situ aircraft measurements are far higher than previously reported CH3OH emission ratios relative to CO from US cities. This may reflect combustion of different fuel types in this area, and possibly photochemical production of CH3OH in Mexico City outflow. TES CH3OH and CO retrievals over the MILAGRO domain show relatively high sensitivity in the 600–800 hPa range, associated with Mexico City pollution outflow. The TES derived ΔCH3OH/ΔCO ratios during MILAGRO are 18–24 ppt ppb−1, which are similar to those observed from the DC-8 (26–39 ppt ppb−1, but lower than the C-130 observations (41–55 ppt ppb−1. Differences between the ΔCH3OH/ΔCO ratios measured aboard the two aircraft preclude an absolute validation of the TES-derived ratios for this dataset. The ΔCH3OH/ΔCO ratios observed from TES over this domain reflect bulk enhancements of CH3OH and CO in Mexico City outflow. Although the TES measurements are not expected to resolve small-scale variability in the ΔCH3OH/ΔCO ratio downwind of the strong source region of Mexico City, it is demonstrated that TES can clearly distinguish differences in the ΔCH3OH/ΔCO ratio due to different source categories

  20. Trace elements in tree rings and their environmental effects: A case study in Xi'an City

    Institute of Scientific and Technical Information of China (English)

    LIU Yu; TA WeiYuan; BAO TingYi; YANG ZengYue; SONG HuiMing; LIU Na; WANG WeiPing; ZHANG HongYi; ZHANG Wei; AN ZhiSheng

    2009-01-01

    Using wet digested method and ICP mass spectrometer, we analyzed the concentration of five trace elements (Cd, Mn, P, Zn and Pb) for the tree rings from both urban and suburbs of Xi'an. At the urban sampling site, one Chinese mahogany (Toona sinensis) disc and one phoenix tree (Firmiana simplex) disc were sampled from a steelworks in Xi'an City. At the suburb site, a Chinese mahogany disc was collected from a village in the south of the City. In addition, some soils near the roots of the sampled trees were collected. The analysis results indicate that the concentration of each of the five elements in annual rings has a positive correlation with the production of the steelworks. Statistical calculations show that Pb and Mn elements were stable without lag effects. That means these two elements do not move between rings. Cd displayed one year moving, P two years and Zn three yeare. These results are quite similar to those found by other methods.

  1. Trace elements in tree rings and their environmental effects: A case study in Xi’an City

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Using wet digested method and ICP mass spectrometer, we analyzed the concentration of five trace elements (Cd, Mn, P, Zn and Pb) for the tree rings from both urban and suburbs of Xi’an. At the urban sampling site, one Chinese mahogany (Toona sinensis) disc and one phoenix tree (Firmiana simplex) disc were sampled from a steelworks in Xi’an City. At the suburb site, a Chinese mahogany disc was collected from a village in the south of the City. In addition, some soils near the roots of the sampled trees were collected. The analysis results indicate that the concentration of each of the five elements in annual rings has a positive correlation with the production of the steelworks. Statistical calculations show that Pb and Mn elements were stable without lag effects. That means these two elements do not move between rings. Cd displayed one year moving, P two years and Zn three years. These results are quite similar to those found by other methods.

  2. Modelling of Informal Settlement Growth with Satellite Data in Latakia City,Syria

    Directory of Open Access Journals (Sweden)

    Yahya Ghassoun

    2013-12-01

    Full Text Available Due to social, economic and political reasons, informal settlements are considered as a challenging problem in the third world countries. These create problems to the society and to the local government. The present study aims to discuss informal settlements of Latakia city (Syria during 1970 and 2005 using satellite data. Where based on all the information available, until today the present study is the first one carried out in Syria concerning the development of informal settlements. In this study, we put a headline to solve the informal settlement problem in Latakia city by achievement 4 goals: • INCORPORATION: This goal requires that the inhabitants of an informal settlement are recognized as full citizens of the city, town or village with which they are associated.• IMPROVEMENT: This goal requires an integrated approach to development, that seeks to meet the most important needs of the whole community. It also requires that those needs and priorities are determined by all the stakeholders. The choice of strategies also requires an inclusive process that takes all factors into account. • DEVELOPMENT: The vital elements of this goal are the provision of opportunities and encouragement. • PLANNING: This goal includes, Anticipate the future. Identification and addressing the implications for the informal settlements in a comprehensive manner. We suggested 4 guiding principles to achieve the previous goals: • Integration: Considering the informal settlements as a part of the whole city, is a very important point in the integration process. • Participation: Participation of people and groups of people with the local authority effectively in a process. • Communication: communication is the exchange of thoughts, messages, information and meeting between people and the authority. • Minimum relocation: is to provide the people with opportunities to stay and settle, because every move is disruptive and costly. Also in the present study

  3. Compact and broadband circularly polarized ring antenna with wide beam-width for multiple global navigation satellite systems

    Institute of Scientific and Technical Information of China (English)

    Zhang Hong-Lin; Hu Bin-Jie; Zhang Xiu-Yin

    2012-01-01

    A compact and broadband circularly polarized (CP) annular ring antenna with wide beam-width is proposed for multiple global navigation satellite systems (GNSS) in the L1 band.The annular ring is excited by two modified L-probes with quadrature phase difference.It has a 36.3% 10-dB return loss bandwidth and a 13% 3-dB axial ratio bandwidth,because of the orthogonal L-probes with 90° phase difference.The measured peak gain of the antenna is 3.9 dBic.It can detect the satellites at lower elevation as its half power beam-width (HPBW) is 113° in both the x-z and y-z planes,achieving a cross-polarization level of larger than 25 dB.Noticeably,the antenna achieves 89% size reduction compared with the conventional half wavelength patch antennas.It can be used in hand-held navigation devices of multiple GNSS such as COMPASS,Galileo,GPS and GLONASS.

  4. Formation of diverse ring-satellite systems around Centaurs through tidal disruption at close encounters with giant planet

    CERN Document Server

    Hyodo, Ryuki; Genda, Hidenori; Ohtsuki, Keiji

    2016-01-01

    Centaurs are minor planets orbiting between Jupiter and Neptune that have or had crossing orbits with one or more giant planets. Recent observations and reinterpretation of previous observations have revealed the existence of ring systems around 10199 Chariklo and 2060 Chiron. However, the origin of the ring systems around such a minor planet is still an open question. Here, we propose that the tidal disruption of a differentiated object that experiences a close encounter with a giant planet could naturally form diverse ring-satellite systems around the Centaurs. During the close encounter, the icy mantle of the passing object is preferentially ripped off by the planet's tidal force and the debris is distributed mostly within the Roche limit of the largest remnant body. Assuming the existence of $20-50$wt% silicate core below the icy mantle, a disk of particles is formed when the objects pass within $0.4-0.8$ of the planet's Roche limit with the relative velocity at infinity $3-6$km s$^{-1}$ and 8h initial sp...

  5. Methodology of traffic flows remote monitoring in the Ural Federal District largest cities using satellite monitoring data

    Science.gov (United States)

    Testeshev, Alexander; Timohovetz, Vera

    2017-01-01

    The article considers the method of remote research of traffic flow characteristics in the largest cities based on satellite monitoring. The aim of the research is to develop mathematical conformities of traffic flow theory that allow interpreting the results of decoding the traffic situation static picture obtained from free online services into primary and derived traffic characteristics. Data on functional dependences of traffic density and traffic flow speed differentiated with respect to transport and road conditions is provided. The developed technique made it possible to minimize resource costs to conduct simultaneous monitoring of traffic flows on the road network in the largest cities of the Ural Federal District.

  6. From the Icy Satellites to Small Moons and Rings: Spectral Indicators by Cassini-VIMS Unveil Compositional Trends in the Saturnian System

    Science.gov (United States)

    Filacchione, G.; Capaccioni, F.; Ciarniello, M.; Nicholson, P. D.; Clark, R. N.; Cuzzi, J. N.; Buratti, B. B.; Cruikshank, D. P.; Brown, R. H.

    2017-01-01

    Despite water ice being the most abundant species on Saturn satellites' surfaces and ring particles, remarkable spectral differences in the 0.35-5.0 μm range are observed among these objects. Here we report about the results of a comprehensive analysis of more than 3000 disk-integrated observations of regular satellites and small moons acquired by VIMS aboard Cassini mission between 2004 and 2016. These observations, taken from very different illumination and viewing geometries, allow us to classify satellites' and rings' compositions by means of spectral indicators, e.g. 350-550 nm - 550-950 nm spectral slopes and water ice band parameters [1,2,3]. Spectral classification is further supported by indirect retrieval of temperature by means of the 3.6 μm I/F peak wavelength [4,5]. The comparison with syntethic spectra modeled by means of Hapke's theory point to different compositional classes where water ice, amorphous carbon, tholins and CO2 ice in different quantities and mixing modalities are the principal endmembers [3, 6]. When compared to satellites, rings appear much more red at visible wavelengths and show more intense 1.5-2.0 μm band depths [7]. Our analysis shows that spectral classes are detected among the principal satellites with Enceladus and Tethys the ones with stronger water ice band depths and more neutral spectral slopes while Rhea evidences less intense band depths and more red visible spectra. Even more intense reddening in the 0.55-0.95 μm range is observed on Iapetus leading hemisphere [8] and on Hyperion [9]. With an intermediate reddening, the minor moons seems to be the spectral link between the principal satellites and main rings [10]: Prometheus and Pandora appear similar to Cassini Division ring particles. Epimetheus shows more intense water ice bands than Janus. Epimetheus' visible colors are similar to water ice rich moons while Janus is more similar to C ring particles. Finally, Dione and Tethys lagrangian satellites show a very

  7. Evaluation of TRMM satellite-based precipitation indexes for flood forecasting over Riyadh City, Saudi Arabia

    Science.gov (United States)

    Tekeli, Ahmet Emre; Fouli, Hesham

    2016-10-01

    Floods are among the most common disasters harming humanity. In particular, flash floods cause hazards to life, property and any type of structures. Arid and semi-arid regions are equally prone to flash floods like regions with abundant rainfall. Despite rareness of intensive and frequent rainfall events over Kingdom of Saudi Arabia (KSA); an arid/semi-arid region, occasional flash floods occur and result in large amounts of damaging surface runoff. The flooding of 16 November, 2013 in Riyadh; the capital city of KSA, resulted in killing some people and led to much property damage. The Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) Real Time (RT) data (3B42RT) are used herein for flash flood forecasting. 3B42RT detected high-intensity rainfall events matching with the distribution of observed floods over KSA. A flood early warning system based on exceedance of threshold limits on 3B42RT data is proposed for Riyadh. Three different indexes: Constant Threshold (CT), Cumulative Distribution Functions (CDF) and Riyadh Flood Precipitation Index (RFPI) are developed using 14-year 3B42RT data from 2000 to 2013. RFPI and CDF with 90% captured the three major flooding events that occurred in February 2005, May 2010 and November 2013 in Riyadh. CT with 3 mm/h intensity indicated the 2013 flooding, but missed those of 2005 and 2010. The methodology implemented herein is a first-step simple and accurate way for flash flood forecasting over Riyadh. The simplicity of the methodology enables its applicability for the TRMM follow-on missions like Global Precipitation Measurement (GPM) mission.

  8. OMI NO2 column densities over North American urban cities: the effect of satellite footprint resolution

    OpenAIRE

    Kim, Hyun Cheol; Lee, Pius; Judd, Laura; Pan, Li; Lefer, Barry

    2016-01-01

    Nitrogen dioxide vertical column density (NO2 VCD) measurements via satellite are compared with a fine-scale regional chemistry transport model, using a new approach that considers varying satellite footprint sizes. Space-borne NO2 VCD measurement has been used as a proxy for surface nitrogen oxide (NOx) emission, especially for anthropogenic urban emission, so accurate comparison of satellite and modeled NO2 VCD is important in determining the future direction of NOx emissi...

  9. Effect of Climatic Conditions on Tree-Ring Widths in Black Locust (Robinia pseudoacacia L. in the city of Wrocław

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    Robert Kalbarczyk

    2016-03-01

    Full Text Available The response of trees to weather conditions, expressed in the tree-ring widths, depends on the extent of urbanization in the area. Specifi c climatic conditions in an urban heat island can be expected to result in growth differences to trees growing in non-urban areas. Accordingly, the aim of this study was to characterize the effect of climatic conditions on tree-ring widths of black locust in the city of Wrocław. Materials consisted of wooden discs taken from felled trees at four sampling sites (4 streets of Wrocław at a height of 1.3 m from the ground. Meteorological data were obtained for the period 1971-2013 from the Institute of Meteorology and Water Management (IMGW in Wrocław. Analysis of the multiannual period showed a significant negative trend in annual ring widths of black locust in the city of Wrocław. A code WROB was assigned to the chronology. The annual ring widths averaged 3.4 mm, ranging from 1.6 to 5.6 mm. In the urban conditions of Wrocław, the air temperature and precipitation significantly influenced the annual ring widths of black locust. The results indicate the need for further research on a larger number of samples.

  10. From Satellites to Rings: The Diversity of the Saturnian System Ices in the VIS-NIR at the End of Cassini-VIMS Nominal Mission

    Science.gov (United States)

    Filacchione, Gianrico; Capaccioni, F.; Tosi, F.; Coradini, A.; Cerroni, P.; Clark, R. N.; Cuzzi, J. N.; Cruikshank, D. P.; Nicholson, P. D.; Hedman, M. M.; McCord, T. B.; Brown, R. H.; Buratti, B. J.; Jaumann, R.; Stephan, K.

    2008-09-01

    After four years of nominal mission, VIMS has observed the whole population of Saturnian icy objects allowing a comparative analysis of the VIS-NIR spectral properties of the regular satellites (Mimas, Enceladus, Tethys, Dione, Rhea, Hyperion, Iapetus, Phoebe), minor moons (Atlas, Prometheus, Pandora, Janus, Epimetheus, Telesto, Calypso) and main rings (A, B, C and Cassini division). The results we present are derived from the whole dataset available at june 2008 which consists of about 1500 full-disk observations of the moons as well as several radial mosaics of the ring system. The most important spectrophotometric indicators (I/F continua, VIS spectral slopes, water and carbon dioxide IR bands strengths and positions) are calculated for each observation in order to identify the disk-integrated compositional units of the satellites, the distribution of water ice respect to "contaminants” abundances and typical regolith grain properties for both satellites and rings. These quantities are varying between the almost pure water ice surfaces of Enceladus and Calypso to the organic and carbon dioxide rich Hyperion, Iapetus and Phoebe. Some significant differences are detected in the VIS colors of co-orbital moons Epimetheus and Janus, with the first very red and therefore similar to Hyperion while the last is more "neutral” these results could help to decipher the origins and evolutional story of these two moons. The water ice band strengths of the A-B rings are the most intense of the Saturnian system denoting a minimal presence of "contaminants” which can be estimated thanks to the 350-520 nm spectral slope. Finally we compare these spectral parameters with some TNOs and outer solar system objects (1995UG5, 90377-Sedna, 1996TO66, Pholus, Triton, Charon, Oberon, Titania) to search for possible analogies. This research was possible thanks to the support of the Italian Space Agency (ASI).

  11. Dental and Periodontal Status of 5 and 12 year old Children in Jakarta and it’s Satellite Cities

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    Melissa Adiatman

    2016-04-01

    Full Text Available Jakarta is the capital city of Indonesia which is surrounded by its satellite cities Bogor, Depok, Tangerang, Bekasi, which can be shortened by Jabodetabek. Objective: The study aims to describe oral health among 5 and 12 years-old children in Jabodetabek. Methods: This cross-sectional oral-health survey was conducted from 2014 with ethics approval. Sample of 5-year-old and 12-year-old Indonesian children living in Jabodetabek were selected using cluster sampling method. One trained examiner performed the clinical examination. Caries experience was measured using DMFT index, severity of decayed teeth was assessed using PUFA index, gingival status and oral hygiene were measured by Loe and Sillness modified index. Results: A total of 390 5-year-old and 458 12-year-old children with balanced proportion between girls and boys participated the survey. The prevalence of caries experience among the 5-year-old children and 12-year-old children were 90% and 84% respectively. The mean DMFT and DT scores among the 5-year-old children and 12-year-old children were 7.5±5.5 and 6.8±4.8; 3.2±2.2 and 2.9±2.1 respectively. Pulp involvement were apparent in 45% and 23% of caries in 5 and 12-year-old children respectively. Most children, 45% 5-year-old children and 92% 12-year-old children had substantial amount of plaque. Moreover, 68% 12-year-old children had gingivitis. Conclusion: Dental caries were prevalent among 5 and 12-year-old Indonesian children in Jakarta its satellite cities. The oral health condition of most of the children were poor.DOI: 10.14693/jdi.v23i1.982

  12. Application of Fuzzy Set Theory and SPOT Satellite Images in Site Selection of Public Libraries (Case Study: Saqqez City, Iran

    Directory of Open Access Journals (Sweden)

    Heydar Dashti Nasserabadi

    2013-06-01

    Full Text Available Easy availability to public libraries is one of the main keys in successful presentation of public library services with high quality will be valueless for those have not access to them. Availability to services should be configured in such a way that maximizes easiness and facility for potential and de facto users. In present research the required number of public libraries and establishment situation of public libraries in Saqqez city in Kurdistan province in North West of Iran were investigated and evaluated by using fuzzy set theory and SPOT 5 satellite images in 2009. In addition, optimum regions for generation of new public libraries were distinguished in city area in form of recommended map. Results showed that weighting variables classes were determined between 0-1 (profusion proportion. Fuzzification each one of effective factors using IDRISI software terminated and after was assigned type and shape membership function. Final map of suitable regions for construction of new public libraries in saqqez city area indicates that none of the libraries were situated in suitable regions.

  13. Neptune's small satellites

    Science.gov (United States)

    Thomas, P.

    1992-04-01

    The small satellites of Neptune and other planets discovered during the Voyager 2 mission are discussed in terms of their composition and relationship to the planetary systems. The satellite Proteus is described in terms of its orbit, five other satellites are described, and they are compared to ther small satellites and systems. Neptune's satellites are hypothesized to be related to the ring system, and the satellite Galatea is related to the confinement of the rings.

  14. The application of very high resolution satellite image in urban vegetation cover investigation: a case study of Xiamen City

    Institute of Scientific and Technical Information of China (English)

    CHENGChengqi; LiBin; MATing

    2003-01-01

    With the technological improvements of satellite sensors, we will acquire more information about the earth so that we have reached a new application epoch of observation on earth environmental change and cartography. But with the enhancement of spatial resolution, some questions have arisen in the application of using traditional image processing and classification methods. Aiming for such questions, we studied the application of IKONOS very high resolution image (1 m) in Xiamen City on Urban Vegetation Cover Investigation and discussed the difference between the very high resolution image and traditional low spatial resolution image at classification,information abstraction etc. It is an advantageous test for the large-scale application of very high resolution data in the future.

  15. Estimating trends of urban residential irrigation extent and rate using satellite imagery in the city of Los Angeles, CA

    Science.gov (United States)

    Chen, Y. J.; McFadden, J. P.; Clarke, K. C.; Roberts, D. A.

    2015-12-01

    Urban residential irrigation is a large component of urban water budgets in Mediterranean climate cities, and plays a significant role for managing landscape vegetation and water resources. This is particularly occurring at cities such as Los Angeles, where water availability is limited during dry summers. This study applied 10-m SPOT 5 satellite imagery and a database of monthly water use records for residential water customers in Los Angeles in order to examine the interactions between vegetation water demand and residential water consumption. Here, we identify the spatial distribution of vegetation greenness and the extent of irrigation rates through water year 2005-2007, including normal, dry, and wet extremes of annual rainfall. Additionally, the water conservation ratio, which is between rates of irrigation and vegetation water demand, is used to assess over-irrigation. Although residential outdoor water usage was found as highest in the dry year, landscape vegetation under water stress that cannot maintain greenness condition as well as in wetter years. However, the decreasing trend of over-irrigation occurred from wet to drier years, since vegetation water demand increased significantly but irrigation rates changed little, implying over-irrigation in urbanized areas. This over watering issue can be implemented by water resource management, and urban planning, especially in current severe California drought.

  16. Planetary Rings

    Science.gov (United States)

    Cuzzi, Jeffrey N.

    1994-01-01

    Just over two decades ago, Jim Pollack made a critical contribution to our understanding of planetary ring particle properties, and resolved a major apparent paradox between radar reflection and radio emission observations. At the time, particle properties were about all there were to study about planetary rings, and the fundamental questions were, why is Saturn the only planet with rings, how big are the particles, and what are they made of? Since then, we have received an avalanche of observations of planetary ring systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron-to-several-meter size particles which comprise ring systems into the complex webs of structure that we now know them to display. Insights gained from studies of these giant dynamical analogs have carried over into improved understanding of the formation of the planets themselves from particle disks, a subject very close to Jim's heart. The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that ring systems are invariably found in association with families of regular satellites, and there is ark emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary ring systems, if not the ring systems themselves, are considerably younger than the solar system

  17. The Special Selection of the Metropolitan Satellite Cities and Functional Layout: Chongqing for Example%大都市圈卫星城市的空间结构与功能布局:以重庆为例

    Institute of Scientific and Technical Information of China (English)

    彭劲松

    2011-01-01

    重庆建设1000平方公里、1000万人口特大城市,应大力发展一批具有综合功能的卫星城市。根据卫星城市布局一般规律,重庆大都市圈应重点打造形成“一核七星、环形拱卫”的中心城区——卫星城市空间结构。在此基础上,建立卫星城市科学的规划和发展机制,创新卫星城市开发模式,完善卫星城市重大基础设施,推进主城与卫星城市产业的多重整合。%To construct 1000 square kilometers, 1000 million mega cities, Chongqing should promote the development of a batch of the comprehensive function of satellite cities. According to the satellite city layout general rules, we propose Chongqing metropolis circle should focus on creating form "a nuclear seven stars, surround and protect" city center - satellite of urban spatial structure. On this basis, establish satellite cities scientific planning and development mechanism, innovation development mode, perfect the satellite city satellite city major infrastructure, promote history-culture and satellite city industry multiple integration.

  18. Urban Visible/SWIR surface reflectance ratios from satellite and sun photometer measurements in Mexico City

    Directory of Open Access Journals (Sweden)

    A. D. de Almeida Castanho

    2007-06-01

    Full Text Available The surface reflectance ratio between the visible (VIS and shortwave infrared (SWIR radiation is an important quantity for the retrieval of the aerosol optical depth (τa from the MODIS sensor data. Based on empirically determined VIS/SWIR ratios, MODIS τa retrieval uses the surface reflectance in the SWIR band (2.1 μm, where the interaction between solar radiation and the aerosol layer is small, to predict the visible reflectances in the blue (0.47 μm and red (0.66 μm bands. Therefore, accurate knowledge of the VIS/SWIR ratio is essential for achieving accurate retrieval of aerosol optical depth from MODIS. The heterogeneity of the surface cover in an urban environment increases the uncertainties in the estimation of the surface reflectance and, consequently, τa. We analyzed the surface reflectance over some distinct surface covers in and around the Mexico City metropolitan area (MCMA using MODIS radiances at 0.66 μm and 2.1 μm. The analysis was performed at 1.5 km×1.5 km spatial resolution. Also, ground-based AERONET sun-photometer data acquired in Mexico City from 2002 to 2005 were analyzed for aerosol optical thickness and other aerosol optical properties. In addition, a network of hand-held sun-photometers deployed in Mexico City, as part of the MCMA-2006 Study during the MILAGRO Campaign, provided an unprecedented measurement of τa in 5 different sites well distributed in the city. We found that the average RED/SWIR ratio representative of the urbanized sites analyzed is 0.73±0.06. This average ratio was significantly different for non-urban sites, which was approximately 0.55. The aerosol optical thickness retrieved from MODIS radiances at a spatial resolution of 1.5 km×1.5 km and averaged within 10 x 10 km boxes were compared with collocated 1-h τa averaged from sun-photometer measurements. The use of the new RED/SWIR ratio of 0.73 in

  19. Effect of air pollution on annual ring width of Pinus densiflora Sieb. et Zucc. and Cryptomeria Japonica D. Don, in Kitakyushu city. Kitakyushu shi deno Sugi, Akamatsu no nenrinhaba ni oyobosu taiki osen no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Y.; Yamashita, T.; Kido, K. (The Kitakyushu Municipal Inst. of Environmental Health Sciences, Kitakyushu (Japan))

    1993-05-10

    There is a little of examples to have numerically evaluated an influence of the air pollution in the field for the long period. By using the conifer species growing in the Kitakyushu city and its periphery, in this report, a relation between the annual ring width and the air pollution has been investigated. Two tree species of Pinus densiflora Sieb. et Zucc. and Cryptomeria japonica D.Don were selected as the tree species. The individuals, with a breast height diameter of about 50cm, more than 10 pieces for each were selected, and then the annual ring specimens for about 50 years upto 1990 were obtained by using the increment borer. The annual ring width was normalized by converting to the annual ring indices. It was found that there is a significant relation between the annual ring indices obtained from the trees in the city and the air pollution, and that the annual ring growth in the 1990's has recovered to a same degree of the growth in the 1940's. As a result of comparing the multiple regression in 3 cases using the air pollution statistics, meteorological statistics and both of them, in addition, it was found that, while both of the air pollution and climatic factors influence on the growth of annual ring, the influence of air pollution is greater than the climate at the stand in the city. 23 refs., 2 figs., 4 tabs.

  20. Contribution of Modis Satellite Image to Estimate the Daily Air Temperature in the Casablanca City, Morocco

    Science.gov (United States)

    Bahi, Hicham; Rhinane, Hassan; Bensalmia, Ahmed

    2016-10-01

    Air temperature is considered to be an essential variable for the study and analysis of meteorological regimes and chronics. However, the implementation of a daily monitoring of this variable is very difficult to achieve. It requires sufficient of measurements stations density, meteorological parks and favourable logistics. The present work aims to establish relationship between day and night land surface temperatures from MODIS data and the daily measurements of air temperature acquired between [2011-20112] and provided by the Department of National Meteorology [DMN] of Casablanca, Morocco. The results of the statistical analysis show significant interdependence during night observations with correlation coefficient of R2=0.921 and Root Mean Square Error RMSE=1.503 for Tmin while the physical magnitude estimated from daytime MODIS observation shows a relatively coarse error with R2=0.775 and RMSE=2.037 for Tmax. A method based on Gaussian process regression was applied to compute the spatial distribution of air temperature from MODIS throughout the city of Casablanca.

  1. CONTRIBUTION OF MODIS SATELLITE IMAGE TO ESTIMATE THE DAILY AIR TEMPERATURE IN THE CASABLANCA CITY, MOROCCO

    Directory of Open Access Journals (Sweden)

    H. Bahi

    2016-10-01

    Full Text Available Air temperature is considered to be an essential variable for the study and analysis of meteorological regimes and chronics. However, the implementation of a daily monitoring of this variable is very difficult to achieve. It requires sufficient of measurements stations density, meteorological parks and favourable logistics. The present work aims to establish relationship between day and night land surface temperatures from MODIS data and the daily measurements of air temperature acquired between [2011-20112] and provided by the Department of National Meteorology [DMN] of Casablanca, Morocco. The results of the statistical analysis show significant interdependence during night observations with correlation coefficient of R2=0.921 and Root Mean Square Error RMSE=1.503 for Tmin while the physical magnitude estimated from daytime MODIS observation shows a relatively coarse error with R2=0.775 and RMSE=2.037 for Tmax. A method based on Gaussian process regression was applied to compute the spatial distribution of air temperature from MODIS throughout the city of Casablanca.

  2. Multitemporal Satellite Images for Knowledge of the Assyrian Capital Cities and for Monitoring Landscape Transformations in the Upper Course of Tigris River

    Directory of Open Access Journals (Sweden)

    Giuseppe Scardozzi

    2011-01-01

    Full Text Available The paper is concerned with the contribution that a rich documentation of multitemporal optical satellite images with high resolution provides for the knowledge of the five great Assyrian capital cities (Ashur, Kar-Tukulti-Ninurta, Kalhu, Dur-Sharrukin, and Nineveh, in northern Iraq. These images also allow monitoring changes of landscape in the higher course of the Tigris during the last half century and document damages in archaeological sites during the two Gulf Wars. The data set, available for each city, consists of panchromatic and multispectral images taken between 2001 and 2007 by modern commercial satellites (Ikonos-2, QuickBird-2, and WorldView-1 and of panchromatic photographs of U.S. spy satellites operating between 1965 and 1969 (Corona KH-4B and Gambit KH-7. These photos were taken before diffusion of mechanized agriculture and the expansion of urban areas, so they are very useful to document many archaeological features and the landscape that has been modified in the last decades, as shown by recent satellite images.

  3. Assessing the impact of urbanization on urban climate by remote satellite perspective: a case study in Danang city, Vietnam

    Science.gov (United States)

    Hoang Khanh Linh, N.; Van Chuong, H.

    2015-04-01

    Urban climate, one of the challenges of human being in 21 century, is known as the results of land use/cover transformation. Its characteristics are distinguished by different varieties of climatic conditions in comparison with those of less built-up areas. The alterations lead to "Urban Heat Island", in which temperature in urban places is higher than surrounding environment. This happens not only in mega cities but also in less urbanized sites. The results determine the change of land use/cover and land surface temperature in Danang city by using multi-temporal Landsat and ASTER data for the period of 1990-2009. Based on the supervised classification method of maximum likelihood algorithm, satellite images in 1990, 2003, 2009 were classified into five classes: water, forest, shrub, agriculture, barren land and built-up area. For accuracy assessment, the error metric tabulations of mapped classes and reference classes were made. The Kappa statistics, derived from error matrices, were over 80% for all of land use maps. An comparison change detection algorithm was made in three intervals, 1990-2003, 2003-2009 and 1990-2009. The results showed that built-up area increased from 8.95% to 17.87% between 1990 and 2009, while agriculture, shrub and barren decreased from 12.98% to 7.53%, 15.72% to 9.89% and 3.88% to 1.77% due to urbanization that resulted from increasing of urban population and economic development, respectively. Land surface temperature (LST) maps were retrieved from thermal infrared bands of Landsat and ASTER data. The result indicated that the temperature in study area increased from 39oC to 41oC for the period of 1990-2009. Our analysis showed that built-up area had the highest LST values, whereas water bodies had the least LST. This study is expected to be useful for decision makers to make an appropriate land use planning which can mitigate the effect to urban climate.

  4. Investigating ambient ozone formation regimes in neighboring cities of shale plays in the Northeast United States using photochemical modeling and satellite retrievals

    Science.gov (United States)

    Chang, Chih-Yuan; Faust, Eric; Hou, Xiangting; Lee, Pius; Kim, Hyun Cheol; Hedquist, Brent C.; Liao, Kuo-Jen

    2016-10-01

    This study investigates long-term (i.e., 2007-2014) fluctuations in ambient ozone formation regimes for cities adjacent to shale plays in the Northeast United States (U.S.). Ozone air quality in many cities of the Northeast U.S. does not meet the U.S. National Ambient Air Quality Standards (NAAQS), and understanding ambient ozone formation regimes is essential to develop effective air pollution mitigation strategies for cities violating the air quality standards. Since 2013, the U.S. has become the world's largest producer of tight oil and natural gas from shale rock, and previous studies show that emissions of air pollutant precursors from shale oil and gas-related activities would have the potential to affect ambient ozone air quality in adjacent cities of shale plays. This work leveraged (1) satellite-retrieved column densities of formaldehyde (HCHO) and nitrogen dioxide (NO2) from multiple instruments (i.e., Ozone Monitoring Instrument (OMI) and Global Ozone Monitoring Experiment-2 (GOME-2)); (2) photochemical air quality modeling and sensitivity analysis; and (3) ratios of satellite-retrieved air pollutant column densities to investigate ambient ozone formation regimes in neighboring cities of shale plays (i.e., Marcellus Shale) in the Northeast U.S. from 2007 to 2014. Our results show that ambient ozone formation in Boston, Pittsburgh, Philadelphia and Washington, D.C. (which are close to Marcellus Shale) was in the NOx -limited or transition regime during the period of study. Ambient ozone formation in New York City was in the transition regime during 2010-2013 and VOC -limited regime during 2007-2009 and in 2014. Based on the result of this study, we conclude that controls NOx emissions would mitigate ozone air pollution from 2007 to 2014 in most of the cities examined in this study. Controls of local VOC emissions would ease ozone air pollution in New York City during the study period. With projected increases in oil and gas production from shale plays in

  5. OMI NO2 column densities over North American urban cities: the effect of satellite footprint resolution

    OpenAIRE

    Kim, H. C.; Lee, P.; L. Judd; Pan, L.; B. Lefer

    2016-01-01

    Nitrogen dioxide vertical column density (NO2 VCD) measurements via satellite are compared with a fine-scale regional chemistry transport model, using a new approach that considers varying satellite footprint sizes. Space-borne NO2 VCD measurement has been used as a proxy for surface nitrogen oxide (NOx) emission, especially for anthropogenic urban emission, so accurate comparison of satellite and modeled NO2 VCD is important in determining the future direction of NOx emissi...

  6. Earth Rings for Planetary Environment Control

    Science.gov (United States)

    Pearson, Jerome; Oldson, John; Levin, Eugene; Carroll, Joseph

    2002-01-01

    For most of its past, large parts of the Earth have experienced subtropical climates, with high sea levels and no polar icecaps. This warmer environment was punctuated 570, 280, and 3 million years ago with periods of glaciation that covered temperate regions with thick ice for millions of years. At the end of the current ice age, a warmer climate could flood coastal cities, even without human-caused global warming. In addition, asteroids bombard the Earth periodically, with impacts large enough to destroy most life on Earth, and the sun is warming inexorably. This paper proposes a concept to solve these problems simultaneously, by creating an artificial planetary ring about the Earth to shade it. Past proposals for space climate control have depended on gigantic engineering structures launched from Earth and placed in Earth orbit or at the Earth-Sun L1 libration point, requiring fabrication, large launch masses and expense, constant control, and repair. Our solution is to begin by using lunar material, and then mine and remove Earth-orbit-crossing asteroids and discard the tailings into Earth orbit, to form a broad, flat ring like those of Saturn. This solution is evaluated and compared with other alternatives. Such ring systems can persist for thousands of years, and can be maintained by shepherding satellites or by continual replenishment from new asteroids to replace the edges of the ring lost by diffusion. An Earth ring at R = 1.3-1.83 RE would shade only the equatorial regions, moderating climate extremes, and could reverse a century of global warming. It could also absorb particles from the radiation belts, making trips to high Earth orbit and GEO safer for humans and for electronics. It would also light the night many times as bright as the full moon. A preliminary design of the ring is developed, including its location, mass, composition, stability, and timescale required. A one-dimensional climate model is used to evaluate the Earth ring performance

  7. Saturn's largest ring.

    Science.gov (United States)

    Verbiscer, Anne J; Skrutskie, Michael F; Hamilton, Douglas P

    2009-10-22

    Most planetary rings in the Solar System lie within a few radii of their host body, because at these distances gravitational accelerations inhibit satellite formation. The best known exceptions are Jupiter's gossamer rings and Saturn's E ring, broad sheets of dust that extend outward until they fade from view at five to ten planetary radii. Source satellites continuously supply the dust, which is subsequently lost in collisions or by radial transport. Here we report that Saturn has an enormous ring associated with its outer moon Phoebe, extending from at least 128R(S) to 207R(S) (Saturn's radius R(S) is 60,330 km). The ring's vertical thickness of 40R(S) matches the range of vertical motion of Phoebe along its orbit. Dynamical considerations argue that these ring particles span the Saturnian system from the main rings to the edges of interplanetary space. The ring's normal optical depth of approximately 2 x 10(-8) is comparable to that of Jupiter's faintest gossamer ring, although its particle number density is several hundred times smaller. Repeated impacts on Phoebe, from both interplanetary and circumplanetary particle populations, probably keep the ring populated with material. Ring particles smaller than centimetres in size slowly migrate inward and many of them ultimately strike the dark leading face of Iapetus.

  8. The diurnal and seasonal characteristics of urban heat island variation in Beijing city and surrounding areas and impact factors based on remote sensing satellite data

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jiahua; HOU Yingyu; LI Guicai; YAN Hao YANG Limin; YAO Fengmei

    2005-01-01

    Based on the land surface temperature (LST), the land cover classification map,vegetation coverage, and surface evapotranspiration derived from EOS-MODIS satellite data, and by the use of GIS spatial analytic technique and multivariate statistical analysis method, the urban heat island (UHI) spatial distribution of the diurnal and seasonal variabilities and its driving forces are studied in Beijing city and surrounding areas in 2001. The relationships among UHI distribution and landcover categories, topographic factor, vegetation greenness, and surface evapotranspiration are analyzed. The results indicate that: (i) The significant UHI occur in Beijing city areas in the four seasons due to high heat capacity and multi-reflection of compression building, as well as with special topographic features of its three sides surrounded by mountains,especially in the summer. The UHI spatial distribution is corresponding with the urban geometry structure profile. The LST difference is approximately 4-6℃ between Beijing city and suburb areas, comparatively is 8- 10℃ between Beijing city area and outer suburb area in northwestern regions. (ii) The UHI distribution and intensity in daytime are different from nighttime in Beijing city area, the nighttime UHI is obvious. However, in the daytime, the significant UHI mainly appears in the summer, the autumn takes second place, and the UHI in the winter and the spring seem not obvious. The surface evapotranspiration in suburb areas is larger than that in urban areas in the summer, and high latent heat exchange is evident, which leads to LST difference between city area and suburb area. (iii) The reflection of surface landcover categories is sensitive to the UHI, the correlation between vegetation greenness and UHI shows obviously negative.The scatterplot shows that there is the negative correlation between NDVI and LST (R2 = 0.6481).The results demonstrate that the vegetation greenness is an important factor for reducing the UHI

  9. Exploring the relationship between monitored ground-based and satellite aerosol measurements over the City of Johannesburg

    CSIR Research Space (South Africa)

    Garland, Rebecca M

    2012-09-01

    Full Text Available This project studied the relationship between aerosol optical depth (AOD) from the Multi-angle Imaging SpectroRadiometer (MISR) instrument on the Terra satellite, and ground-based monitored particulate matter (PM) mass concentrations measured...

  10. Mapping Urbanization Dynamics in Major Cities of Colombia, Ecuador, Perú, and Bolivia Using Night-Time Satellite Imagery

    OpenAIRE

    Parés-Ramos, Isabel K.; Nora L. Álvarez-Berríos; T. Mitchell. Aide

    2013-01-01

    By 2050, 90% of the population in Latin America will live in cities, but there is a lack of up-to-date spatial information about the urban extent and patterns of urbanization in cities of this region. In this study, we analyzed population growth, urban density and urbanization dynamics between 1992 and 2009 in the major cities of Bolivia, Colombia, Ecuador and Perú using Google Earth and DMSP/OLS night-time lights imagery. We used Google Earth to map the urban extent, and time series of night...

  11. Multitemporal High-Resolution Satellite Images for the Study and Monitoring of an Ancient Mesopotamian City and its Surrounding Landscape: The Case of Ur

    Directory of Open Access Journals (Sweden)

    Giacomo Di Giacomo

    2012-01-01

    Full Text Available The paper concerns the use of multitemporal high-resolution satellite images for the study of the ancient city of Ur, in southern Mesopotamia, inaccessible to scholars from 2003. The acquired dataset is composed by two Gambit KH-7 (1966 and one Corona KH-4B (1968 declassified spy space photos and by few images taken by the recent satellites for civilian use QuickBird-2 (2002, 2004, 2007, Ikonos-2 (2008, and WorldView-1 (2008. The processing of all these images and the integration with ASTER and SRTM DEMs allowed the acquisition of new data about the topographical layout of the city and its monuments and ancient roads; the georeferencing of all archaeological remains and traces visible on the images allowed the upgrade of the archaeological map of Ur. The research also provided important data concerning the reconstruction of the surrounding landscape, where a lot of traces of old channels and riverbeds of the Euphrates were identified in areas much modified and altered during the last decades by urbanization and agricultural works. Moreover, the multitemporal images allowed the monitoring of the conservation of the archaeological area, particularly before and after second Gulf War.

  12. Subsidence hazard and risk assessments for Mexico City: An interdisciplinary analysis of satellite-derived subsidence map (PSInSAR) and census data.

    Science.gov (United States)

    Solano Rojas, D. E.; Cabral-Cano, E.; Wdowinski, S.; Hernaández Espriú, A.; Falorni, G.; Bohane, A.

    2014-12-01

    The Mexico City Metropolitan Area is the largest urban center in the American continent, with 20.4 millions of inhabitants, representing 17.8% of the total population of the country. Over the past several decades Mexico City has been experienced rapid subsidence, up to ~370 mm/yr, caused by groundwater extraction. The subsidence rate is inhomogeneous, as it controlled by the local geology. Unconsolidated sediments tend to compact and induce rapid subsidence, whereas subsurface volcanic rocks are less prone to subsidence. Intensive faulting in the city has been observed in areas of differential deformation; in these areas buildings and infrastructure are highly damaged. Quantification of subsidence-induce damage is needed for establishing the magnitude of the phenomenon. Our study uses three data sources: a satellite-derived subsidence map, census information of population distribution for 2010, and information on buildings and infrastructure. The subsidence map was calculated from 29 SAR scene acquired by the Envisat satellite during the years 2003-2010 using the Persistent Scatterers Interferometry (PSI) method with the SqueeSAR algorithm. The information of the census of population comes from the National Institute of Statistics and Geography (INEGI), which also provides the information about infrastructure. We intersected the information from the three maps using a geographic information system (GIS), which cover an area of 1, 640 km2. As subsidence-induced damage occurs mainly in areas of differential subsidence, we based the GIS analysis on the subsidence gradients, rather than subsidence rates. In order to evaluate subsidence-induced faulting risk, we generated a risk matrix that worked as the main parameter to create a risk map. We then reclassified the urban area into 5 zones according to the related risk, with R0 for the lowest risk and R4 for the highest. Our counting showed that 350 km2 of the city is located in an urban area of high to very high risk

  13. 佛山市“一环”快速干线绿化养护及环境整治%Green Space Conservation and Environment Improvement along Ring One Express in Fushan City

    Institute of Scientific and Technical Information of China (English)

    廖颖殷

    2011-01-01

    Ring One Express of Fushan City has been constructed and put in use for years,and some greening tree species have degraded.In this context,how to conserve the green space and maintain surrounding environment have become a difficult issue to tackle.The paper introduced the green space conservation technologies and environment improvement of urban expresses adopted in the overall upgrading of green space along Ring One Express of Fushan City.With the conservation technology and environment improvement,better landscape effect along the express has been achieved and economic and ecological objectives also taken account of.%文章阐述了城市快速干线绿化养护管理技术及环境整治,以期达到既保证"一环"快速干线绿化的景观效果,又兼顾经济、生态的目标。

  14. Satellite and ground-based sensors for the Urban Heat Island analysis in the city of Rome

    DEFF Research Database (Denmark)

    Fabrizi, Roberto; Bonafoni, Stefania; Biondi, Riccardo

    2010-01-01

    In this work, the trend of the Urban Heat Island (UHI) of Rome is analyzed by both ground-based weather stations and a satellite-based infrared sensor. First, we have developed a suitable algorithm employing satellite brightness temperatures for the estimation of the air temperature belonging...... to the layer of air closest to the surface. UHI spatial characteristics have been assessed using air temperatures measured by both weather stations and brightness temperature maps from the Advanced Along Track Scanning Radiometer (AATSR) on board ENVISAT polar-orbiting satellite. In total, 634 daytime...... and nighttime scenes taken between 2003 and 2006 have been processed. Analysis of the Canopy Layer Heat Island (CLHI) during summer months reveals a mean growth in magnitude of 3-4 K during nighttime and a negative or almost zero CLHI intensity during daytime, confirmed by the weather stations. © 2010...

  15. Neptune's ring system.

    Science.gov (United States)

    Porco, C. C.; Nicholson, P. D.; Cuzzi, J. N.; Lissauer, J. J.; Esposito, L. W.

    The authors review the current state of knowledge regarding the structure, particle properties, kinematics, dynamics, origin, and evolution of the Neptune rings derived from Earth-based and Voyager data. Neptune has a diverse system of five continuous rings - 2 broad (Galle and Lassell) and 3 narrow (Adams, Le Verrier, and Arago) - plus a narrow discontinuous ring sharing the orbit of one of its ring-region satellites, Galatea. The outermost Adams ring contains the only arcs observed so far in Voyager images. The five arcs vary in angular extent from ≡1° to ≡10°, and exhibit internal azimuthal structure with typical spatial scales of ≡0.5°. All five lie within ≡40° of longitude. Dust is present throughout the Neptune system and measureable quantities of it were detected over Neptune's north pole. The Adams ring (including the arcs) and the Le Verrier ring contain a significant fraction of dust. The Neptune ring particles are probably red, and may consist of ice "dirtied" with silicates and/or some carbon-bearing material. A kinematic model for the arcs derived from Voyager data, the arcs' physical characteristics, and their orbital geometry and phasing are all roughly in accord with single-satellite arc shepherding by Galatea, though the presence of small kilometer-sized bodies embedded either within the arcs or placed at their Lagrange points may explain some inconsistencies with this model.

  16. Urban Land Cover Change Modelling Using Time-Series Satellite Images: A Case Study of Urban Growth in Five Cities of Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Abdullah F. Alqurashi

    2016-10-01

    Full Text Available This study analyses the expansion of urban growth and land cover changes in five Saudi Arabian cities (Riyadh, Jeddah, Makkah, Al-Taif and the Eastern Area using Landsat images for the 1985, 1990, 2000, 2007 and 2014 time periods. The classification was carried out using object-based image analysis (OBIA to create land cover maps. The classified images were used to predict the land cover changes and urban growth for 2024 and 2034. The simulation model integrated the Markov chain (MC and Cellular Automata (CA modelling methods and the simulated maps were compared and validated to the reference maps. The simulation results indicated high accuracy of the MC–CA integrated models. The total agreement between the simulated and the reference maps was >92% for all the simulation years. The results indicated that all five cities showed a massive urban growth between 1985 and 2014 and the predicted results showed that urban expansion is likely to continue going for 2024 and 2034 periods. The transition probabilities of land cover, such as vegetation and water, are most likely to be urban areas, first through conversion to bare soil and then to urban land use. Integrating of time-series satellite images and the MC–CA models provides a better understanding of the past, current and future patterns of land cover changes and urban growth in this region. Simulation of urban growth will help planners to develop sustainable expansion policies that may reduce the future environmental impacts.

  17. Flash Flood Hazard Mapping Using Satellite Images and GIS Tools: A case study of Najran City, Kingdom of Saudi Arabia (KSA

    Directory of Open Access Journals (Sweden)

    Ismail Elkhrachy

    2015-12-01

    Full Text Available Flash flood in the cities led to high levels of water in the streets and roads, causing many problems such as bridge collapse, building damage and traffic problems. It is impossible to avoid risks of floods or prevent their occurrence, however it is plausible to work on the reduction of their effects and to reduce the losses which they may cause. Flash flood mapping to identify sites in high risk flood zones is one of the powerful tools for this purpose. Mapping flash flood will be beneficial to urban and infrastructure planners, risk managers and disaster response or emergency services during extreme and intense rainfall events. The objective of this paper is to generate flash flood map for Najran city, Saudi Arabia, using satellite images and GIS tools. To do so, we use SPOT and SRTM DEMs data for which accuracy assessment is achieved by using check points, obtained by GPS observations. Analytical Hierarchical Process (AHP is used to determine relative impact weight of flood causative factors to get a composite flood hazard index (FHI. The causative factors in this study are runoff, soil type, surface slope, surface roughness, drainage density, distance to main channel and land use. All used data are finally integrated in an ArcMap to prepare a final flood hazard map for study area. The areas in high risk flood zones are obtained by overlaying the flood hazard index map with the zone boundaries layer. The affected population number and land area are determined and compared.

  18. Vascular ring

    Science.gov (United States)

    ... subclavian and left ligamentum ateriosus; Congenital heart defect - vascular ring; Birth defect heart - vascular ring ... Vascular ring is rare. It accounts for less than 1% of all congenital heart problems. The condition ...

  19. Use of Satellite Images to map Flood Extension around the city of Saint Louis in the Senegal River Estuary

    Directory of Open Access Journals (Sweden)

    Aliou Dia

    2006-04-01

    Full Text Available The traditional method of landsat satellite data combination and the gathering of important information made it possible to produce a Geographical Information System to monitor floods in the lower estuary of the Senegal River valley (Sandholt,I., Fog, B. & Fensholt, R., 2001. This technical approach is a powerful tool for combining important information for a better comprehension of the floods and the characterization of surface qualities on the estuary. By way of a multi-temporal approach, the study team established the qualitative and quantitative impact of floods on the various geographical objects, a detailed cartography of the land use and the surfaces flooded in 1998 and 1999. The study undertaken in Saint Louis made it possible to consider surfaces flooded in 1999, and to understand the extent of these floods compared to those of 1998. The constitution of a tool of decision-making aid makes it possible to have information relating to the extent of the flood, the scope of flooded surfaces and to detect the more exposed zones in order to establish a hierarchical map according to the percentage of exposure to the risk of the geographical objects affected by the floods (populations, road infrastructures and tracks, medical and social infrastructures and perimeters of cultures (agriculture.

  20. The eSurge-Venice project: altimeter and scatterometer satellite data to improve the storm surge forecasting in the city of Venice

    Science.gov (United States)

    Zecchetto, Stefano; De Biasio, Francesco; Umgiesser, Georg; Bajo, Marco; Vignudelli, Stefano; Papa, Alvise; Donlon, Craig; Bellafiore, Debora

    2013-04-01

    On the framework of the Data User Element (DUE) program, the European Space Agency is funding a project to use altimeter Total Water Level Envelope (TWLE) and scatterometer wind data to improve the storm surge forecasting in the Adriatic Sea and in the city of Venice. The project will: a) Select a number of Storm Surge Events occurred in the Venice lagoon in the period 1999-present day b) Provide the available satellite Earth Observation (EO) data related to the Storm Surge Events, mainly satellite winds and altimeter data, as well as all the available in-situ data and model forecasts c) Provide a demonstration Near Real Time service of EO data products and services in support of operational and experimental forecasting and warning services d) Run a number of re-analysis cases, both for historical and contemporary storm surge events, to demonstrate the usefulness of EO data The re-analysis experiments, based on hindcasts performed by the finite element 2-D oceanographic model SHYFEM (https://sites.google.com/site/shyfem/), will 1. use different forcing wind fields (calibrated and not calibrated with satellite wind data) 2. use Storm Surge Model initial conditions determined from altimeter TWLE data. The experience gained working with scatterometer and Numerical Weather Prediction (NWP) winds in the Adriatic Sea tells us that the bias NWP-Scatt wind is negative and spatially and temporally not uniform. In particular, a well established point is that the bias is higher close to coasts then offshore. Therefore, NWP wind speed calibration will be carried out on each single grid point in the Adriatic Sea domain over the period of a Storm Surge Event, taking into account of existing published methods. Point #2 considers two different methodologies to be used in re-analysis tests. One is based on the use of the TWLE values from altimeter data in the Storm Surge Model (SSM), applying data assimilation methodologies and trying to optimize the initial conditions of the

  1. Space communication link propagation data for selected cities within the multiple beam and steerable antenna coverage areas of the advanced communications technology satellite

    Science.gov (United States)

    Manning, Robert M.

    1988-01-01

    Rain attenuation propagation data for 68 cities within the coverage area of the multiple beam and steerable antennas of the Advanced Communications Technology Satellite (ACTS) are presented. These data provide the necessary data base for purposes of communication link power budgeting and rain attenuation mitigation controller design. These propagation parameters are derived by applying the ACTS Rain Attenuation Prediction Model to these 68 locations. The propagation parameters enumerated in tabular form for each location are as follows: (1) physical description of the link and location (e.g., latitude, longitude, antenna elevation angle, etc.), link availability versus attenuation margin (also in graphical form), fading time across fade depths of 3, 5, 8, and 15 dB versus fade duration, and required fade control response time for controller availabilities of 99.999, 99.99, 99.9, and 99 percent versus sub-threshold attenuation levels. The data for these specific locations can be taken to be representative of regions near these locations.

  2. Ring blowers. Ring blower

    Energy Technology Data Exchange (ETDEWEB)

    Nakahara, Y.; Okamura, T.; Takahashi, M. (Fuji Electric Co. Ltd., Tokyo (Japan))

    1991-06-10

    Features, structures and several products of ring blowers were outlined. The ring blower is featured by its medium characteristics because it is higher in air pressure than a turboblower and larger in airflow than a vane blower, and it is applicable flexibly to not only air blasting but various industrial fields such as suction transfer. As several products corresponding to various fields, the followings were outlined: the low noise type with optimum shapes of inlet, outlet and casing cover for reducing noises by 10 dB or more, the heat resistant, water-tight and explosion-proof types suitable for severe environmental conditions, the multi-voltage type for every country served at different voltages, the high air pressure type with two pressure rise stages, and the large airflow type with a wide impeller. In addition, as special use products, the glass fiber reinforced unsatulated polyester ring blower for respiration apparatus, and the variable speed blushless DC motor-driven one for medical beds were outlined. 2 refs., 9 figs., 1 tab.

  3. Saturn's Rings

    Science.gov (United States)

    Cuzzi, J. N.

    2014-12-01

    The rings are changing before our eyes; structure varies on all timescales and unexpected things have been discovered. Many questions have been answered, but some answers remain elusive (see Cuzzi et al 2010 for a review). Here we highlight the major ring science progress over the mission to date, and describe new observations planned for Cassini's final three years. Ring Composition and particle sizes: The rings are nearly all water ice with no other ices - so why are they reddish? The C Ring and Cassini Division are "dirtier" than the more massive B and A Rings, as shown by near-IR and, recently, microwave observations. Particle sizes, from stellar and radio occultations, vary from place to place. Ring structure, micro and macro: numerous spiral density waves and ubiquitous "self-gravity wakes" reveal processes which fostered planet formation in the solar system and elsewhere. However, big puzzles remain regarding the main ring divisions, the C Ring plateau structures, and the B Ring irregular structure. Moonlets, inside and out, seen and unseen: Two gaps contain sizeable moonlets, but more gaps seem to contain none; even smaller embedded "propeller" objects wander, systematically or randomly, through the A ring. Rubble pile ringmoons just outside the rings may escaped from the rings, and the recently discovered "Peggy" may be trying this as we watch. Impact bombardment of the rings: Comet fragments set the rings to rippling on century-timescales, and boulders crash through hourly; meanwhile, the constant hail of infalling Kuiper belt material has a lower mass flux than previously thought. Origin and Age of the Rings: The ring mass and bombardment play key roles. The ring mass is well known everywhere but in the B Ring (where most of it is). New models suggest how tidal breakup of evolving moons may have formed massive ancient rings, of which the current ring is just a shadow. During its last three years, the Cassini tour profile will allow entirely new

  4. Towards a theory for the Uranian rings

    Science.gov (United States)

    Goldreich, P.; Tremaine, S.

    1979-01-01

    Interparticle collisions, radiation drag, and differential precession all tend to disrupt the rings of Uranus. The first two effects lead to radial spreading which would disrupt a free ring in less than or approximately 100,000,000 yr. It is proposed that the rings are confined in radius by gravitational torques from a series of small satellites that orbit with the ring system. Differential precession tends to destroy the apse alignment of the elliptical epsilon ring. It is suggested that apse alignment is maintained by the self-gravity of the ring. The resulting mass of the epsilon ring is approximately 5 times 10 to the 18th power g. Its radial confinement requires (for example) a pair of satellites of mass approximately 10 to the 19th power g, in circular orbits roughly 500 km away on either side of the ring

  5. [Landscape pattern changes at village scale using high resolution satellite images: A case study in low-slope hilly area of Dali City, Northwestern Yunnan Province].

    Science.gov (United States)

    Zhao, Ming-yue; Peng, Jian; Liu, Yan-xu; Zhang, Tian

    2015-12-01

    Human activity is the main driving force of the change of land cover and landscape patterns. However, there are few studies focusing on the mechanism of human-induced change of land cover and landscape patterns at village scale. In this study, taking low-slope hilly area of Dali City, Northwestern Yunnan Province as a case study area, high resolution satellite images were introduced to find out the rules of land cover and landscape pattern changes, i.e. GeoEye-1 of 2009 and World- View-3 of 2014. The object-oriented and human-computer-interaction approaches were applied to interpret the images using ArcGIS 10.2 and ENVI 5.2. The results showed that, the main land cover types in the study area were forest land, paddy field and dry land in 2009, with forest, bulldozed unbuilt ground and paddy field in 2014, accounting for 82.8% and 70.9% of the total area, respectively. The land cover transition showed that, during 2009-2014, the main land cover change flows were from forest land, paddy field and dry land, to bulldozed unbuilt ground and construction land. Furthermore, the area of bulldozed but unbuilt land had increased to be 531.57 hm² in 2014, which mainly came from forest land (42.8%), dry land (21.7%), and paddy field (14.2%). Landscape pattern change was characterized as the increase of patch quantity and density, the decrease of mean patch size, the complication of patch shape, the fragmentation of landscape patches, and the diversification of landscape patterns.

  6. Vortex rings

    Energy Technology Data Exchange (ETDEWEB)

    Akhmetov, D.G. [Lavrentiev Institute of Hydrodynamics, Novosibirsk (Russian Federation)

    2009-07-01

    This book presents a comprehensive coverage of the wide field of vortex rings. The book presents the results of systematic experimental investigations, theoretical foundation, as well as the practical applications of vortex rings, such as the extinction of fires at gushing gas and oil wells. All the basic properties of vortex rings as well as their hydrodynamic structures are presented. Special attention is paid to the formation and motion of turbulent vortex rings. (orig.)

  7. The Enceladus Ring

    Science.gov (United States)

    2006-01-01

    [figure removed for brevity, see original site] The Enceladus Ring (labeled) This excellent view of the faint E ring -- a ring feature now known to be created by Enceladus -- also shows two of Saturn's small moons that orbit within the ring, among a field of stars in the background. The E ring extends from three to eight Saturn radii -- about 180,000 kilometers (118,000 miles) to 482,000 kilometers (300,000 miles). Its full extent is not visible in this view. Calypso (22 kilometers, or 14 miles across) and Helene (32 kilometers, or 20 miles across) orbit within the E ring's expanse. Helene skirts the outer parts of the E ring, but here it is projected in front of a region deeper within the ring. Calypso and Helene are trojan satellites, or moons that orbit 60 degrees in front or behind a larger moon. Calypso is a Tethys trojan and Helene is a trojan of Dione. An interesting feature of note in this image is the double-banded appearance of the E-ring, which is created because the ring is somewhat fainter in the ringplane than it is 500-1,000 kilometers (300-600 miles) above and below the ringplane. This appearance implies that the particles in this part of the ring have nonzero inclinations (a similar affect is seen in Jupiter's gossamer ring). An object with a nonzero inclination does not orbit exactly at Saturn's ringplane. Instead, its orbit takes it above and below the ringplane. Scientists are not entirely sure why the particles should have such inclinations, but they are fairly certain that the reason involves Enceladus. One possible explanation is that all the E ring particles come from the plume of icy material that is shooting due south out of the moon's pole. This means all of the particles are created with a certain velocity out of the ringplane, and then they orbit above and below that plane. Another possible explanation is that Enceladus produces particles with a range of speeds, but the moon gravitationally scatters any particles that lie very close to

  8. An explanation for Neptune's ring arcs

    Science.gov (United States)

    Porco, Carolyn C.

    1991-08-01

    The Voyager mission revealed a complex system of rings and ring arcs around Neptune and uncovered six new satellites, four of which occupy orbits well inside the ring region. Analysis of Voyager data shows that a radial distortion with an amplitude of approximately 30 kilometers is traveling through the ring arcs, a perturbation attributable to the nearby satellite Galatea. Moreover, the arcs appear to be azimuthally confined by a resonant interaction with the same satellite, yielding a maximum spread in ring particle semimajor axes of 0.6 kilometer and a spread in forced eccentricities large enough to explain the arc's 15-kilometer radial widths. Additional ring arcs discovered in the course of this study give further support to this model.

  9. A census of Gulf Stream rings, spring 1975

    Science.gov (United States)

    Richardson, P. L.; Worthington, L. V.; Cheney, R. E.

    1978-01-01

    During 1975 several shipboard expendable bathythermograph surveys plus satellite infrared imagery provided a nearly synoptic view of the distribution and number of Gulf Stream rings in the western North Atlantic. Twelve rings were identified; nine were cyclonic (cold core) rings and three were anticyclonic (warm core) rings. This is the largest number of rings ever observed during a short period of time (4 months). Evidence suggests that the mean movement of these rings was southwestward.

  10. Satellite formation. II

    Science.gov (United States)

    Harris, A. W.

    1978-01-01

    A satellite formation model is extended to include evolution of planetary ring material and elliptic orbital motion. In this model the formation of the moon begins at a later time in the growth of the earth, and a significant fraction of the lunar material is processed through a circumterrestrial debris cloud where volatiles might have been lost. Thus, the chemical differences between the earth and moon are more plausibly accounted for. Satellites of the outer planets probably formed in large numbers throughout the growth of those planets. Because of rapid inward evolution of the orbits of small satellites, the present satellite systems represent only satellites formed in the last few percent of the growths of their primaries. The rings of Saturn and Uranus are most plausibly explained as the debris of satellites disrupted within the Roche limit. Because such a ring would collapse onto the planet in the course of any significant further accretion by the planet, the rings must have formed very near or even after the conclusion of accretion.

  11. Ring theory

    CERN Document Server

    Rowen, Louis H

    1991-01-01

    This is an abridged edition of the author's previous two-volume work, Ring Theory, which concentrates on essential material for a general ring theory course while ommitting much of the material intended for ring theory specialists. It has been praised by reviewers:**""As a textbook for graduate students, Ring Theory joins the best....The experts will find several attractive and pleasant features in Ring Theory. The most noteworthy is the inclusion, usually in supplements and appendices, of many useful constructions which are hard to locate outside of the original sources....The audience of non

  12. Planetary Rings

    CERN Document Server

    Tiscareno, Matthew S

    2011-01-01

    Planetary rings are the only nearby astrophysical disks, and the only disks that have been investigated by spacecraft. Although there are significant differences between rings and other disks, chiefly the large planet/ring mass ratio that greatly enhances the flatness of rings (aspect ratios as small as 1e-7), understanding of disks in general can be enhanced by understanding the dynamical processes observed at close-range and in real-time in planetary rings. We review the known ring systems of the four giant planets, as well as the prospects for ring systems yet to be discovered. We then review planetary rings by type. The main rings of Saturn comprise our system's only dense broad disk and host many phenomena of general application to disks including spiral waves, gap formation, self-gravity wakes, viscous overstability and normal modes, impact clouds, and orbital evolution of embedded moons. Dense narrow rings are the primary natural laboratory for understanding shepherding and self-stability. Narrow dusty...

  13. New Views of Jupiter's Rings

    Science.gov (United States)

    Burns, J. A.

    1998-09-01

    Jupiter's rings are the archetype of ethereal planetary rings (very-low optical-depth bands containing micron-sized "dust"). As a result of much improved observations by Galileo (Ockert-Bell* -- most citations are et al. and Icarus in press* or this meeting) and Keck (de Pater*), we now understand the nature of such rings. The ring has three components: a 104 km-thick toroidal halo (1.4-1.7 RJ; normal optical depth t = 10-6), a thin main ring (1.7-1.8 RJ; t = 10-6), and a pair of exterior gossamer rings (1.8-3.5RJ; t = 10-7). The main ring has patchy ( 20-30 percent) brightness. The ring is reddish and its particles satisfy a -2.5 differential power-law size distribution. Because particle lifetimes are brief, the rings must be continually regenerated, by collisions into parent bodies, which may be unseen or may be the known small ring-moons (Thomas*, Simonelli). The gossamer ring seems to be collisional ejecta derived from the ring-moons Amalthea and Thebe, and evolving inward by Poynting-Robertson drag (Burns). The particles drift through many electromagnetic resonances, clustering around synchronous orbit, which produce jumps in the particles' inclinations (Hamilton). The main ring is probably debris from Adrastea and Metis, which orbit in the equatorial plane. The halo particles are driven vertically by electromagnetic forces, which may be resonant (Schaffer & Burns) or not (Horanyi & Cravens). When halo orbits become highly distorted, particles are lost into Jupiter. Similar faint rings may be attendant to all small, close-in satellites (Showalter).

  14. Internet access for everybody: The satellite solution

    Science.gov (United States)

    Wittig, Manfred

    2009-01-01

    The use of the Internet has been grown tremendously within the last decade to more than one billion subscribers. The other five billion people on Earth cannot enjoy the possibilities offered by the Internet. The digital divide is everywhere: in the developing as well as in the developed part of the world. In the developing countries basic communication needs (voice, IP access) need to be provided to a large population not living in cities. In the developed part of the world people residing outside the large cities, on the nice country side, have still difficulties to get broadband access. The reason being, that the investment to install the network infrastructure to this minority part of the population is a major part of the total investment for the network. The benefit for the telecom operators is marginal to get these customers on board. In this paper an analysis of the Internet and satellite development is being presented and based on these historical data a prediction of a possible evolution of satellite communications and broadband access is performed. One result is that the capacity of the GEO ring at the Ka-band alone would allow to provide to each individual on Earth in 2050 (assumed to be 10 billion people) a monthly capacity of about 1 Gbyte for a charge of 1$ per month.

  15. SUPRAMITRAL RING

    Directory of Open Access Journals (Sweden)

    Rajesh G

    2011-11-01

    Full Text Available Supra mitral ring is a rare cause for congenital mitral valve obstr uction. The reported incidence of supramitral ring is 0.2-0.4% in general population and 8% in patients with congenital mitral valve disease. The condition is characterized by an abnormal ridge of connective tissue often circumferential in shape ,on the atrial side of the mitral valve encroaching on the orifice of the mitral valve. It may adhere to the leaflets of the valve and restrict their movements. Although a supramitral ring may be rarely nonobstructive, it often results in mitral valve inflow obstruction.

  16. Determinantal rings

    CERN Document Server

    Bruns, Winfried

    1988-01-01

    Determinantal rings and varieties have been a central topic of commutative algebra and algebraic geometry. Their study has attracted many prominent researchers and has motivated the creation of theories which may now be considered part of general commutative ring theory. The book gives a first coherent treatment of the structure of determinantal rings. The main approach is via the theory of algebras with straightening law. This approach suggest (and is simplified by) the simultaneous treatment of the Schubert subvarieties of Grassmannian. Other methods have not been neglected, however. Principal radical systems are discussed in detail, and one section is devoted to each of invariant and representation theory. While the book is primarily a research monograph, it serves also as a reference source and the reader requires only the basics of commutative algebra together with some supplementary material found in the appendix. The text may be useful for seminars following a course in commutative ring theory since a ...

  17. Cave Rings

    Science.gov (United States)

    2010-10-13

    hypothesis, that cave rings are formed in the same manner as coffee rings[3], that is, due to the enhanced deposition at the edges of sessile drops ...ring’ is the deposit formed when a sessile drop of a solution containing dissolved particles, such as coffee or salt, dries. This was investigated by...who expanded on Deegan et al.[3] to find an exact form for the evaporation flux over a sessile drop . It turns out that solving 179 for the flux is

  18. Vascular rings.

    Science.gov (United States)

    Backer, Carl L; Mongé, Michael C; Popescu, Andrada R; Eltayeb, Osama M; Rastatter, Jeffrey C; Rigsby, Cynthia K

    2016-06-01

    The term vascular ring refers to congenital vascular anomalies of the aortic arch system that compress the esophagus and trachea, causing symptoms related to those two structures. The most common vascular rings are double aortic arch and right aortic arch with left ligamentum. Pulmonary artery sling is rare and these patients need to be carefully evaluated for frequently associated tracheal stenosis. Another cause of tracheal compression occurring only in infants is the innominate artery compression syndrome. In the current era, the diagnosis of a vascular ring is best established by CT imaging that can accurately delineate the anatomy of the vascular ring and associated tracheal pathology. For patients with a right aortic arch there recently has been an increased recognition of a structure called a Kommerell diverticulum which may require resection and transfer of the left subclavian artery to the left carotid artery. A very rare vascular ring is the circumflex aorta that is now treated with the aortic uncrossing operation. Patients with vascular rings should all have an echocardiogram because of the incidence of associated congenital heart disease. We also recommend bronchoscopy to assess for additional tracheal pathology and provide an assessment of the degree of tracheomalacia and bronchomalacia. The outcomes of surgical intervention are excellent and most patients have complete resolution of symptoms over a period of time. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. The origin and evolution of planetary rings

    Science.gov (United States)

    Harris, A. W.

    1984-01-01

    Roche (1847) suggested that Saturn's rings may be the fragments of a disrupted satellite rather than the uncoagulated remnant of a circumplanetary disk from which the regular satellites formed. In order to address this unresolved central issue, attention is given to the dynamical processes of viscous spreading, gas drag, particulate coagulation, and the effect of further matter infall from heliocentric orbit onto the planet/disk, all of which act on a gas/solid disk in Keplerian motion. In view of these considerations, it is suggested that rings were created by the disruption of large satellites which were less sensitive to the destructive processes present during the planet's formation. This hypothesis explains the presence of shepherd satellites, such as large collision fragments, which coexist in the same orbital range as the ring particles.

  20. 500 Cities: City Boundaries

    Data.gov (United States)

    U.S. Department of Health & Human Services — This city boundary shapefile was extracted from Esri Data and Maps for ArcGIS 2014 - U.S. Populated Place Areas. This shapefile can be joined to 500 Cities...

  1. Topological rings

    CERN Document Server

    Warner, S

    1993-01-01

    This text brings the reader to the frontiers of current research in topological rings. The exercises illustrate many results and theorems while a comprehensive bibliography is also included. The book is aimed at those readers acquainted with some very basic point-set topology and algebra, as normally presented in semester courses at the beginning graduate level or even at the advanced undergraduate level. Familiarity with Hausdorff, metric, compact and locally compact spaces and basic properties of continuous functions, also with groups, rings, fields, vector spaces and modules, and with Zorn''s Lemma, is also expected.

  2. Ring interferometry

    CERN Document Server

    Malykin, Grigorii B; Zhurov, Alexei

    2013-01-01

    This monograph is devoted to the creation of a comprehensive formalism for quantitative description of polarized modes' linear interaction in modern single-mode optic fibers. The theory of random connections between polarized modes, developed in the monograph, allows calculations of the zero shift deviations for a fiber ring interferometer. The monograph addresses also the

  3. Perspective for a compact electrostatic storage ring : Miniature quadrilateral electrostatic storage ring

    OpenAIRE

    El Ghazaly, Mohamed ,

    2013-01-01

    International audience; A flexible, compact-sized electrostatic storage ring is being designed at the King Abdulaziz City for Science and Technology (KACST). The design features a quadratic shaped ring with four 90° bending corners and relies exclusively on quadrupoles to act on the stored ion beam.

  4. Satellite Communication.

    Science.gov (United States)

    Technology Teacher, 1985

    1985-01-01

    Presents a discussion of communication satellites: explains the principles of satellite communication, describes examples of how governments and industries are currently applying communication satellites, analyzes issues confronting satellite communication, links mathematics and science to the study of satellite communication, and applies…

  5. On SAP-rings

    OpenAIRE

    Zhixiang, Wu

    2006-01-01

    The rings whose simple right modules are absolutely pure are called right $SAP$-rings. We give a new characterization of right $SAP$ rings, right $V$ rings, and von Neumann regular rings. We also obtain a new decomposition theory of right selfinjective von Neumann regular rings. The relationships between $SAP$-rings, $V$-rings, and von Neumann regular rings are explored. Some recent results obtained by Faith are generalized and the results of Wu-Xia are strengthened.

  6. Rings from Close Encounters

    Science.gov (United States)

    Kohler, Susanna

    2016-09-01

    Weve recently discovered narrow sets of rings around two minor planets orbiting in our solar system. How did these rings form? A new study shows that they could be a result of close encounters between the minor planets and giants like Jupiter or Neptune.Unexpected Ring SystemsPositions of the centaurs in our solar system (green). Giant planets (red), Jupiter trojans (grey), scattered disk objects (tan) and Kuiper belt objects (blue) are also shown. [WilyD]Centaurs are minor planets in our solar system that orbit between Jupiter and Neptune. These bodies of which there are roughly 44,000 with diameters larger than 1 km have dynamically unstable orbits that cross paths with those of one or more giant planets.Recent occultation observations of two centaurs, 10199 Chariklo and 2060 Chiron, revealed that these bodies both host narrow ring systems. Besides our four giant planets, Chariklo and Chiron are the only other bodies in the solar system known to have rings. But how did these rings form?Scientists have proposed several models, implicating collisions, disruption of a primordial satellite, or dusty outgassing. But a team of scientists led by Ryuki Hyodo (Paris Institute of Earth Physics, Kobe University) has recently proposed an alternative scenario: what if the rings were formed from partial disruption of the centaur itself, after it crossed just a little too close to a giant planet?Tidal Forces from a GiantHyodo and collaborators first used past studies of centaur orbits to estimate that roughly 10% of centaurs experience close encounters (passing within a distance of ~2x the planetary radius) with a giant planet during their million-year lifetime. The team then performed a series of simulations of close encounters between a giant planet and a differentiated centaur a body in which the rocky material has sunk to form a dense silicate core, surrounded by an icy mantle.Some snapshots of simulation outcomes (click for a closer look!) for different initial states of

  7. Ring aggregation pattern of Human Travel Trips

    CERN Document Server

    Wang, Zi-Yang; Zhu, Peng; Qin, Yong; Jia, Li-Min

    2015-01-01

    Although a lot of attentions have been paid to human mobility, the relationship between travel pattern with city structure is still unclear. Here we probe into this relationship by analyzing the metro passenger trip data.There are two unprecedented findings. One, from the average view a linear law exists between the individual's travel distance with his original distance to city center. The mechanism underlying is a travel pattern we called "ring aggregation", i.e., the daily movement of city passengers is just aggregating to a ring with roughly equal distance to city center.Interestingly, for the round trips the daily travel pattern can be regarded as a switching between the home ring at outer area with the office ring at the inner area. Second, this linear law and ring aggregation pattern seems to be an exclusive characteristic of the metro system. It can not be found in short distance transportation modes, such as bicycle and taxi, neither as multiple transportation modes. This means the ring aggregation p...

  8. Analysis of satellite-observed CO2 and CH4 of GOSAT for estimation of GHG emissions from power plants and large cities from space

    Science.gov (United States)

    Oda, Tomohiro; Maksyutov, Shamil; Saito, Makoto; Valsala, Vinu; Ganshin, Alexander; Andres, Robert; Koyama, Yuji; Ito, Akihiko; Yoshida, Yukio; Yokota, Tatsuya

    2010-05-01

    National GHG inventories, which are reported on annual basis by country, are a tool to monitor the compliance of GHG emission reduction. National emissions are calculated according to the local activity statistics by sector and thus total emissions and emission changes from the past are obtained. National inventories are presently the only tool available to give a measure of national emissions, although these might not accurately reflect the true quantity of national emissions due to data quality, calculation methods, and time lag. We present an attempt to directly monitor GHG emissions, especially from intense sources such as large power plants and populated cities using GOSAT observations. Our preliminary analysis suggested that emissions from such intense sources cause changes in XCO2, which are detectable by GOSAT, in low wind condition. Since August 2009 we have requested GOSAT targeted mode measurements over large power plants and cities. The large power plants were selected from CARMA (Carbon Monitoring and Action) database by emission intensity, and cities were selected by population ranking. Until to December 2009, 137 XCO2 measurements over 98 observation points were successfully obtained. We evaluated difference between the data at requested points and background concentration, which we defined as monthly mean concentration over 800 km vicinity. An analysis using observational data suggested that XCO2 over requested points might be higher than zonal mean and background concentrations on average, and the range of the difference (1.07 ppm for 3 months) appears to be close to prior estimates. The level of uncertainty at this point (71 % of the mean value) is still at the level of the value itself, however a simple estimate suggests that it can be reduced to about 10% assuming a larger number of measurements, improvements on the retrieval and 5-year operation of GOSAT.

  9. Flash Flood Hazard Mapping Using Satellite Images and GIS Tools: A case study of Najran City, Kingdom of Saudi Arabia (KSA)

    OpenAIRE

    Ismail Elkhrachy

    2015-01-01

    Flash flood in the cities led to high levels of water in the streets and roads, causing many problems such as bridge collapse, building damage and traffic problems. It is impossible to avoid risks of floods or prevent their occurrence, however it is plausible to work on the reduction of their effects and to reduce the losses which they may cause. Flash flood mapping to identify sites in high risk flood zones is one of the powerful tools for this purpose. Mapping flash flood will be beneficial...

  10. Stability of Neptune's ring arcs in question

    Science.gov (United States)

    Dumas, Christophe; Terrile, Richard J.; Smith, Bradford A.; Schneider, Glenn; Becklin, E. E.

    1999-08-01

    Although all four of the gas-giant planets in the Solar System have ring systems, only Neptune exhibits `ring arcs'-stable clumps of dust that are discontinuous from each other. Two basic mechanisms for confining the dust to these arcs have been proposed. The firstrelies on orbital resonances with two shepherding satellites, while the second invokes a single satellite (later suggested to be Galatea) to produce the observed ring arc structures. Here we report observations of the ring arcs and Galatea, which show that there isa mismatch between the locations of the arcs and the site of Galatea's co-rotation inclined resonance. This result calls into question Galatea's sole role in confining the arcs.

  11. Existence of undiscovered Uranian satellites

    Energy Technology Data Exchange (ETDEWEB)

    Boice, D.C.

    1986-04-01

    Structure in the Uranian ring system as observed in recent occultations may contain indirect evidence for the existence of undiscovered satellites. Using the Alfven and Arrhenius (1975, 1976) scenario for the formation of planetary systems, the orbital radii of up to nine hypothetical satellites interior to Miranda are computed. These calculations should provide interesting comparisons when the results from the Voyager 2 encounter with Uranus are made public. 15 refs., 1 fig., 1 tab.

  12. Origami rings

    CERN Document Server

    Buhler, Joe; de Launey, Warwick; Graham, Ron

    2010-01-01

    Motivated by a question in origami, we consider sets of points in the complex plane constructed in the following way. Let $L_\\alpha(p)$ be the line in the complex plane through $p$ with angle $\\alpha$ (with respect to the real axis). Given a fixed collection $U$ of angles, let $\\RU$ be the points that can be obtained by starting with $0$ and $1$, and then recursively adding intersection points of the form $L_\\alpha(p) \\cap L_\\beta(q)$, where $p, q$ have been constructed already, and $\\alpha, \\beta$ are distinct angles in $U$. Our main result is that if $U$ is a group with at least three elements, then $\\RU$ is a subring of the complex plane, i.e., it is closed under complex addition and multiplication. This enables us to answer a specific question about origami folds: if $n \\ge 3$ and the allowable angles are the $n$ equally spaced angles $k\\pi/n$, $0 \\le k < n$, then $\\RU$ is the ring $\\Z[\\zeta_n]$ if $n$ is prime, and the ring $\\Z[1/n,\\zeta_{n}]$ if $n$ is not prime, where $\\zeta_n := \\exp(2\\pi i/n)$ is ...

  13. Resonance capture and Saturn's rings

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, C.W.

    1986-05-01

    We have assigned the resonances apparently responsible for the stabilization of the Saturn's shepherd satellites and for the substructure seen in the F-ring and the ringlets in the C-ring. We show that Saturn's narrow ringlets have a substructure determined by three-body resonances with Saturn's ringmoons and the sun. We believe such resonances have important implications to satellite formation. 17 refs., 1 fig., 1 tab.

  14. Simulation of Rings about Ellipsoidal Bodies

    Science.gov (United States)

    Gupta, Akash; Nadkarni-Ghosh, Sharvari; Sharma, Ishan

    2016-10-01

    Recent discovery of rings around Chariklo, a centaur orbiting the Sun (F. Braga-Ribas et al., 2014) and speculations of rings around minor planet, Chiron (Ortiz et al., 2015), Saturn's satellites, Rhea (Jones et al., 2008; Schenk et al., 2011), Iapetus (Ip, 2006) or exoplanets, suggest that rings about non-spherical bodies is perhaps a more general phenomenon than anticipated. As a first step towards understanding such systems, we examine the dynamical behavior of rings around similar bodies using N-body simulations. Our code employs the `local simulation method' (Wisdom & Tremaine, 1988; Salo, 1995) and accounts for particle interactions via collisions using Discrete Element Method (Cundall & Strack, 1978; Bhateja et al., 2016) and mutual gravitation. The central body has been modeled as an axisymmetric ellipsoid characterized by its axis ratio, or defined via characteristic frequencies (circular, vertical and epicyclic frequency) representing the gravitational field of an axisymmetric body. We vary the central body's characterizing parameter and observe the change in various ring properties like the granular temperature, impact frequency, radial width and vertical thickness. We also look into the effect on ring properties upon variation in the size of the central body-ring system. Further, we investigate the role of characteristic frequencies in dictating the ring dynamics, and how this could help in qualitatively estimating the ring dynamics about any arbitrary central body with symmetry about the equatorial plane and the axis normal to it.

  15. Poynting-Robertson Effects in Saturn's F Ring

    Science.gov (United States)

    Giuliatti Winter, S. M.

    2000-10-01

    Observations from the Voyager spacecraft have shown that the narrow F ring of Saturn is composed of micrometer-sized particles that extend inward from the core (Showalter et al., Icarus, 1992; Graps et al., Icarus, 1984). These small particles can be disturbed by the effects of the Poynting-Robertson drag (PR drag), which cause their orbital decay. The F ring particles are also perturbed by the nearby satellite Prometheus. The effects of the satellite are intensified during the closest approach with the ring particles. At this special configuration gaps are formed in the ring as result of scattering of particles in the direction of the planet (Giuliatti Winter et al.,PSS, 2000). In this work we analyze the effects of the PR drag combined with the perturbations of the satellite Prometheus. Our results show that depending on the initial conditions of the ring particles the satellite can avoid the orbital decay caused by the PR drag (Giuliatti Winter & Guimar\\ aes, 2000). There are some resonance locations in the region between Prometheus and the F ring, some of them with the satellite Atlas (Giuliatti Winter, 1994). We also analyze the orbital evolution of a dust ring particle subjected to PR drag and Atlas perturbations. Acknowledgement: SMGW (Proc. 99/11965) thanks FAPESP for the financial support.

  16. Rapid evolution of a Gulf Stream warm-core ring

    Science.gov (United States)

    Joyce, T.; Backus, R.; Cowles, T.; Baker, K.; Blackwelder, P.; Brown, O.; Evans, R.; Olson, D.; Fryxell, G.; Mountain, D.

    1984-01-01

    Satellite images are used to show that major alterations in the structure of Gulf Stream warm-core rings can occur during very short periods of two to five days when an interaction with the Gulf Stream is particularly intense. The role of these interactions in the evolution of a ring are discussed.

  17. Prime rings with PI rings of constants

    CERN Document Server

    Kharchenko, V K; Rodríguez-Romo, S

    1996-01-01

    It is shown that if the ring of constants of a restricted differential Lie algebra with a quasi-Frobenius inner part satisfies a polynomial identity (PI) then the original prime ring has a generalized polynomial identitiy (GPI). If additionally the ring of constants is semiprime then the original ring is PI. The case of a non-quasi-Frobenius inner part is also considered.

  18. Towards a theory for Neptune's arc rings

    Science.gov (United States)

    Goldreich, P.; Tremaine, S.; Borderies, N.

    1986-01-01

    It is proposed that the incomplete rings of Neptune consist of a number of short arcs centered on the corotation resonances of a single satellite. The satellite must have a radius of the order of 100 km or more and move on an inclined orbit. Corotation resonances are located at potential maxima. Thus, mechanical energy dissipated by interparticle collisions must be continually replenished to prevent the arcs from spreading. It is shown that each corotation resonance is associated with a nearby Lindblad resonance, which excites the ring particles' orbital eccentricity, thus supplying the energy required to maintain the arc. The ultimate energy reservoir is the satellite's orbital energy. Therefore, interaction with the arcs damps the satellite's orbital inclination. The self-gravity of the arcs limits their contraction and enforces a relation between arc length and mass. The estimated arc masses are so small, of the order of 10 to the 16th g, that the satellite's orbital inclination suffers negligible decay over the age of the solar system. The inferred surface mass densities are comparable to those found in the major rings of Saturn and Uranus.

  19. Radical theory of rings

    CERN Document Server

    Gardner, JW

    2003-01-01

    Radical Theory of Rings distills the most noteworthy present-day theoretical topics, gives a unified account of the classical structure theorems for rings, and deepens understanding of key aspects of ring theory via ring and radical constructions. Assimilating radical theory's evolution in the decades since the last major work on rings and radicals was published, the authors deal with some distinctive features of the radical theory of nonassociative rings, associative rings with involution, and near-rings. Written in clear algebraic terms by globally acknowledged authorities, the presentation

  20. Analysing the New Saturnian Rings, R/2004 S1 and R/2004 S2

    Science.gov (United States)

    Winter, S. M. Giuliatti; Sfair, R.; Mourão, D. C.; Bastos, T. A.

    2005-12-01

    The Cassini-Huygens arrival into the Saturnian system brought a large amount of data about the satellites and rings. Two diffuse rings were found in the region between the A ring and Prometheus. R/2004 S1 is coorbital to Atlas and R/2004 S2 is close to Prometheus. In this work we analysed the closest approach between Prometheus and both rings. As a result we found that the satellite removes particles from R/2004 S2 ring. Long-term numerical simulations showed that some particles can cross the F ring region . The well known region of the F ring, where small satellites are present and particles are being taking from the ring, gains a new insight with the presence of particles from R/2004 S2 ring. The computation of the Lyapunov Characteristic Exponent reveled that the R/2004 S2 ring lies in a chaotic region while R/2004 S1 ring and Atlas are in a stable region. Atlas is responsible for the formation of three regimes in the R/2004 S1 ring, as expected for a satellite embedded in a ring.

  1. Image city

    DEFF Research Database (Denmark)

    2003-01-01

    Image city exhibition explores a condition of mediation, through a focus on image and sound narratives with a point of departure on a number of Asian cities.......Image city exhibition explores a condition of mediation, through a focus on image and sound narratives with a point of departure on a number of Asian cities....

  2. The effects of the solar radiation pressure on the F-ring particles

    Science.gov (United States)

    Sfair, R.; Giuliatti Winter, S.

    The Saturn s F-ring is a narrow ring orbiting outside the main ring system of Saturn It is located between two close satellites Prometheus the interior one and Pandora The gravitational interactions between the ring particles and the satellites can be responsible for several structures found in this ring Showalter et al 1992 showed that the F-ring material could be divided into two regions a core composed by centimeter or large particles and a dust envelope composed by mu m particles Recent observations by Cassini instruments brought more complications to this region with the discovery of two new faint rings between the A ring and Prometheus one of these rings has the satellite Atlas embedded on it These new rings are tenuous like the dust envelope which surround the F-ring and the solar radiation force can play a significant role in this dynamical environment In this work we analysed the effects due to the solar radiation forces on the particles of the F ring and the two new discovered rings In this analysis we also included the perturbation of the satellite Prometheus on the F ring particles and the satellite Atlas on the new rings particles We have numerically simulated particles with size ranging from 1-500 mu m in radius The density of these particles was assumed to be 1g cm 3 Our results show that a sample of scattered F ring particles can be trapped due to Prometheus effects However the particles from the new discovered rings have a short lifetime due to the solar radiation pressure Only those particles coorbital to Atlas

  3. Satellite Sanitary Systems in Kampala, Uganda

    NARCIS (Netherlands)

    Letema, S.; Van Vliet, B.; Van Lier, J.B.

    2011-01-01

    Satellite sewage collection and treatment systems have been independently developed and managed in East African cities outside the centrally planned and sewered areas. A satellite approach is a promising provisioning option parallel to public sewerage for middle- and high-income residential areas, e

  4. Satellite Sanitary Systems in Kampala, Uganda

    NARCIS (Netherlands)

    Letema, S.C.; Vliet, van B.J.M.; Lier, van J.B.

    2012-01-01

    Satellite sewage collection and treatment systems have been independently developed and managed in East African cities outside the centrally planned and sewered areas. A satellite approach is a promising provisioning option parallel to public sewerage for middle- and high-income residential areas, e

  5. Carbon Monitoring Satellite (CarbonSat: assessment of scattering related atmospheric CO2 and CH4 retrieval errors and first results on implications for inferring city CO2 emissions

    Directory of Open Access Journals (Sweden)

    M. Buchwitz

    2013-05-01

    Full Text Available Carbon Monitoring Satellite (CarbonSat is one of two candidate missions for ESA's Earth Explorer 8 (EE8 satellite – the selected one to be launched around the end of this decade. The objective of the CarbonSat mission is to improve our understanding of natural and anthropogenic sources and sinks of the two most important anthropogenic greenhouse gases (GHG carbon dioxide (CO2 and methane (CH4. The unique feature of CarbonSat is its "GHG imaging capability", which is achieved via a combination of high spatial resolution (2 km × 2 km and good spatial coverage (wide swath and gap-free across- and along-track ground sampling. This capability enables global imaging of localized strong emission source such as cities, power plants, methane seeps, landfills and volcanos and better disentangling of natural and anthropogenic GHG sources and sinks. Source/sink information can be derived from the retrieved atmospheric column-averaged mole fractions of CO2 and CH4, i.e. XCO2 and XCH4, via inverse modeling. Using the most recent instrument and mission specification, an error analysis has been performed using the BESD/C retrieval algorithm. We focus on systematic errors due to aerosols and thin cirrus clouds, as this is the dominating error source especially with respect to XCO2 systematic errors. To compute the errors for each single CarbonSat observation in a one year time period, we have developed an error parameterization scheme based on six relevant input parameters: we consider solar zenith angle, surface albedo in two bands, aerosol and cirrus optical depth, and cirrus altitude variations but neglect, for example, aerosol type variations. Using this method we have generated and analyzed one year of simulated CarbonSat observations. Using this data set we estimate that scattering related systematic errors are mostly (approx. 85% below 0.3 ppm for XCO2 (XCH4 (XCO2 and 7 ppb for XCH4 (1-sigma. The number of quality filtered observations over cloud and

  6. 卫星城居民出行特征及出行方式选择模型研究%Residents′Travel Characteristics and Model of Travel Mode Choice for Satellite City

    Institute of Scientific and Technical Information of China (English)

    谢秋婷; 温旭丽

    2015-01-01

    Study on residents′travel characteristics and travel mode choice behaviors is the basis and premise to solve traffic problems of satellite city. Taking Pukou district of Nanjing as an example, the res⁃idents′travel OD survey data was processed and excavated by Access. The residents′travel characteris⁃tics status was summarized from aspects of travel frequency, travel purpose, travel mode, travel time and its distribution. The major factors influencing the travel mode choice of satellite city residents were exca⁃vated and quantified. By data mining, the multinomial travel choice Logit model was established. It was fitted and calibrated through SPSS. Taking the public transport as an example, the major factors influenc⁃ing the choice of bus travel which were gender, age and whether having bus IC card were conducted. The fitting accuracy was tested using the calculation and predicted value. The result shows that the errors of predicted values are acceptable except for non-motorized vehicle.%卫星城居民出行特征及出行方式选择研究是解决卫星城交通问题的基础和前提。以南宁市浦口区为例,通过Access数据库对居民出行OD调查数据进行处理挖掘,从居民的出行频次、出行目的、出行方式、出行时耗及出行时间分布五方面对卫星城居民出行特征进行研究,总结出浦口区居民出行特征现状;挖掘并量化影响卫星城居民出行方式选择的关键因素,利用浦口区居民出行调查数据,构建居民出行方式选择多项Logit模型,通过SPSS软件进行模型拟合和标定。在模型拟合结果中,以公交车为例进行拟合结果分析,可得到影响选择公交出行的主要因素——性别、年龄以及有无公交IC卡,并通过计算以及模型预测值对模型拟合精度进行校验。结果显示,除非机动车预测效果较差以外,其余预测误差均在可接受范围内。

  7. Satellite RNAs and Satellite Viruses.

    Science.gov (United States)

    Palukaitis, Peter

    2016-03-01

    Satellite RNAs and satellite viruses are extraviral components that can affect either the pathogenicity, the accumulation, or both of their associated viruses while themselves being dependent on the associated viruses as helper viruses for their infection. Most of these satellite RNAs are noncoding RNAs, and in many cases, have been shown to alter the interaction of their helper viruses with their hosts. In only a few cases have the functions of these satellite RNAs in such interactions been studied in detail. In particular, work on the satellite RNAs of Cucumber mosaic virus and Turnip crinkle virus have provided novel insights into RNAs functioning as noncoding RNAs. These effects are described and potential roles for satellite RNAs in the processes involved in symptom intensification or attenuation are discussed. In most cases, models describing these roles involve some aspect of RNA silencing or its suppression, either directly or indirectly involving the particular satellite RNA.

  8. Stirling engine piston ring

    Science.gov (United States)

    Howarth, Roy B.

    1983-01-01

    A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

  9. Birth Control Ring

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Ring KidsHealth > For Teens > Birth Control Ring A A A What's in this article? ... español Anillo vaginal anticonceptivo What Is It? The birth control ring is a soft, flexible, doughnut-shaped ring ...

  10. “景观·系统”的水系景观规划策略——以唐山环城水系为例%"Landscape & System" as Planning Strategy of River Network——Case Study of City-ringed River Network in Tangshan

    Institute of Scientific and Technical Information of China (English)

    邹裕波; 刘敬文; 么春华

    2013-01-01

    在国家宏观产业结构调整的背景下,唐山城内陡河沿岸的工厂将陆续迁出,移入曹妃甸工业园区.在此契机之下,为了适应城市生态建设和百姓生活需要,唐山提出了以市中心区内陡河、青龙河、李各庄河为基础构建环城水系的设想.受系统论影响,环城水系规划把水系景观作为开放的系统,围绕系统的整体性、层次性和关联性3个重要特征的体现,通过系统的涉水规划、景观的系统和系统的景观营造的三大策略统筹滨水区的生态环境建设与空间开发,完成环城水系的景观规划.%The factories situated along the Douhe River in Tangshan are planned to be moved gradually into Caofeidian Industrial Area from the inner city in the coming future according to the macroscopic adjustment of the national industrial structure, In the context Tangshan municipality has put forward to build the city-ringed river network based on Douhe River, Qinglong River and Ligezhuang River which run through the downtown of the city. The great vision will be beneficial to eco-city construction as well the citizens' life. Landscape of river network has been regarded as an open system within the planning of city-ringed river network in Tangshan inspired by systematology. The planning, embodying correspondingly three important characters of the system which are integrity, hierarchy and relevance, has been already fulfilled by means of three strategies including systematic planning in water realm, landscape as system and landscape created systematically.

  11. Actin Rings of Power.

    Science.gov (United States)

    Schwayer, Cornelia; Sikora, Mateusz; Slováková, Jana; Kardos, Roland; Heisenberg, Carl-Philipp

    2016-06-20

    Circular or ring-like actin structures play important roles in various developmental and physiological processes. Commonly, these rings are composed of actin filaments and myosin motors (actomyosin) that, upon activation, trigger ring constriction. Actomyosin ring constriction, in turn, has been implicated in key cellular processes ranging from cytokinesis to wound closure. Non-constricting actin ring-like structures also form at cell-cell contacts, where they exert a stabilizing function. Here, we review recent studies on the formation and function of actin ring-like structures in various morphogenetic processes, shedding light on how those different rings have been adapted to fulfill their specific roles.

  12. Alternative loop rings

    CERN Document Server

    Goodaire, EG; Polcino Milies, C

    1996-01-01

    For the past ten years, alternative loop rings have intrigued mathematicians from a wide cross-section of modern algebra. As a consequence, the theory of alternative loop rings has grown tremendously. One of the main developments is the complete characterization of loops which have an alternative but not associative, loop ring. Furthermore, there is a very close relationship between the algebraic structures of loop rings and of group rings over 2-groups. Another major topic of research is the study of the unit loop of the integral loop ring. Here the interaction between loop rings and group ri

  13. A Traveling Feature in Saturn's Rings

    CERN Document Server

    Rehnberg, Morgan E; Brown, Zarah L; Albers, Nicole; Sremčević, Miodrag; Stewart, Glen R

    2016-01-01

    The co-orbital satellites of Saturn, Janus and Epimetheus, swap radial positions every 4.0 years. Since \\textit{Cassini} has been in orbit about Saturn, this has occurred on 21 January in 2006, 2010, and 2014. We describe the effects of this radial migration in the Lindblad resonance locations of Janus within the rings. When the swap occurs such that Janus moves towards Saturn and Epimetheus away, nonlinear interference between now-relocated density waves launches a solitary wave that travels through the rings with a velocity approximately twice that of the local spiral density wave group velocity in the A ring and commensurate with the spiral density wave group velocity in the B ring.

  14. GRISM Spectophotometry of the Uranus Ring

    Science.gov (United States)

    Smith, Bradford

    1997-07-01

    Details of the near-infrared spectral reflectance of the Uranus rings are poorly known, because of problems associated with the scattered light from the planet. Grism spectroscopy of the brightest part of the Epsilon ring will be made with the planet just outside the field of view. To minimize the glare from Uranus, the observations should made when the widest part of the Epsilon ring is at a position angle of approximately 174 degrees. This is one in a series of observations designed to intercompare the near-infrared spectral reflectivity of dark objects in the solar system. Some record of processes that occurred within the Uranus subnebula may be left on the surfaces of the ring particles or the surface coatings of the associated dark inner satellites.

  15. Utilizing Chinese high-resolution satellite images for inspection of unauthorized constructions in Beijing

    Institute of Scientific and Technical Information of China (English)

    LI DeRen; WANG Mi; HU Fen

    2009-01-01

    After Beijing wins the bit to host the 29th Olympic Games, in order to manifest the technical support advantages and capabilities of the autonomously-developed RS and GIS based change detection techniques in 2008 Beijing Olympic Games, and from the standpoints of executing new city planning, relieving the traffic congestion as well as maintaining the historic features, an automatic satellite monitoring system has been studied and established to accomplish the mission of unauthorized construction inspection within the Sixth Ring Road of Beijing city quarterly, by adopting the CBERS-2 satellite images and combining technologies of GIS, GPS, etc. This article discusses the applicable procedures and key issues when utilizing such Chinese satellite images and relevant techniques to discover the illegal constructions, and introduces the monitoring system from both the design and implementation aspects; additionally, some typical application cases in the practice of the system are also illustrated. The monitoring system can timely supply abundant information to facilitate the policy-making of relevant planning departments, thus providing consolidate technical support to eliminate the illegal constructing behaviors in the blossom. During the five years' excellent performance, it has helped China save large amounts of expenditures for processing of unauthorized constructed buildings.

  16. Centriolar satellites

    DEFF Research Database (Denmark)

    Tollenaere, Maxim A X; Mailand, Niels; Bekker-Jensen, Simon

    2015-01-01

    Centriolar satellites are small, microscopically visible granules that cluster around centrosomes. These structures, which contain numerous proteins directly involved in centrosome maintenance, ciliogenesis, and neurogenesis, have traditionally been viewed as vehicles for protein trafficking...... highlight newly discovered regulatory mechanisms targeting centriolar satellites and their functional status, and we discuss how defects in centriolar satellite components are intimately linked to a wide spectrum of human diseases....

  17. Satellite theory

    Science.gov (United States)

    Kozai, Y.

    1981-04-01

    The dynamical characteristics of the natural satellite of Mars, Jupiter, Saturn, Uranus and Neptune are analyzed on the basis of the solar tidal perturbation factor and the oblateness factor of the primary planet for each satellite. For the inner satellites, for which the value of the solar tidal factor is much smaller than the planetary oblateness factor, it is shown that the eccentricity and inclination of satellite orbits are generally very small and almost constant; several pairs of inner satellites are also found to exhibit commensurable mean motions, or secular accelerations in mean longitude. In the case of the outer satellites, for which solar perturbations are dominant, secular perturbations and long-period perturbations may be derived by the solution of equations of motion reduced to one degree of freedom. The existence of a few satellites, termed intermediary satellites, for which the solar tidal perturbation is on the order of the planetary oblateness factor, is also observed, and the pole of the orbital plane of the satellite is noted to execute a complex motion around the pole of the planet or the orbital plane of the planet.

  18. On JB-Rings

    Institute of Scientific and Technical Information of China (English)

    Huanyin CHEN

    2007-01-01

    A ring R is a QB-ring provided that aR + bR = R with a, b ∈ R implies that there exists a y ∈ R such that a+by ∈ R-1q. It is said that a ring R is a JB-ring provided that R/J(R) is a QB-ring, where J(R) is the Jacobson radical of R. In this paper, various necessary and sufficient conditions, under which a ring is a JB-ring, are established. It is proved that JB-rings can be characterized by pseudo-similarity. Furthermore, the author proves that R is a J B-ring iff so is R/J(R)2.

  19. Electrostatic discharges in Saturn's B-ring

    Science.gov (United States)

    Warwick, J. W.; Romig, J. H.; Evans, D. R.

    1983-01-01

    The Voyager observations of electrical discharges in Saturn's rings strongly support earlier speculations on the role played by electrostatics, magnetic fields, and lightning phenomena in the primitive solar system. They also suggest conditions then by direct analogy rather than by extrapolating backwards through time from conditions now. The observed discharges show a pronounced 10h periodicity, which suggests a source in Keplerian orbit at 1.80 + or - 0.01 Saturn radii. In that region, the B ring is thicker than optical depth 1.8 for about 5,000 km. At 1.805 + or - 0.001 Saturn radii, however, the ring is virtually transparent for a gap of width 200 m. It is concluded that a small satellite orbits Saturn at that radius and clears the gap. The gap edges must prevent diffusive filling of the gap by fine material which is especially abundant at this position in the rings and would otherwise destroy the gap in minutes. The discharges represent the satellite's interaction with the outer edge of the gap. Spoke formation may involve the interaction of ring material in the vicinity of the gap.

  20. Beer City

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Shandong Province’s Qingdao is becoming China’s great beer city sicenically located on a peninsula over-looking the Pacific Ocean, Qingdao, |or Tsingtao, is a coastal city soaked in two kinds of foam. One floats in

  1. On semi ring bornologies

    Science.gov (United States)

    Imran, A. N.; Rakhimov, I. S.; Husain, Sh. K. Said

    2016-06-01

    Our main focus in this work is to introduce new structure bornological semi rings. This generalizes the theory of algebraic semi rings from the algebraic setting to the framework of bornological sets. We give basic properties for this new structure. As well as, We study the fundamental construction of bornological semi ring as product, inductive limits and projective limits and their extensions on bornological semi ring. Additionally, we introduce the category of bornological semi rings and study product and pullback (fiber product) in the category of bornological semi rings.

  2. Sin City?

    DEFF Research Database (Denmark)

    Svarer, Michael; Gautier, Pieter A.; Teulings, Coen n.

    , the ones who stay in the city have significant higher divorce rates. Similarly, for the couples who married outside the city, the ones who move to the city are more likely to divorce. This correlation can be explained by both a causal and a sorting effect. We disentangle them by using the timing...

  3. City PLANTastic

    DEFF Research Database (Denmark)

    The city is going green. From New York to Copenhagen vegetables are enthusiastically planted on city squares, and buildings are turning green everywhere . The word “plant” is on everyone’s lips, reflecting a growing desire to solve ecological, technical and social challenges in the city. Hovever,...... and urbanism, who reflect upon the multiple roles of plants in the future city through their most recent projects. The theme for the 2012 World in Denmark conference is City PLANTastic, which will also be explored by researchers through their works....

  4. Satellite Communications

    CERN Document Server

    Pelton, Joseph N

    2012-01-01

    The field of satellite communications represents the world's largest space industry. Those who are interested in space need to understand the fundamentals of satellite communications, its technology, operation, business, economic, and regulatory aspects. This book explains all this along with key insights into the field's future growth trends and current strategic challenges. Fundamentals of Satellite Communications is a concise book that gives all of the key facts and figures as well as a strategic view of where this dynamic industry is going. Author Joseph N. Pelton, PhD, former Dean of the International Space University and former Director of Strategic Policy at Intelstat, presents a r

  5. Groups, rings, modules

    CERN Document Server

    Auslander, Maurice

    2014-01-01

    This classic monograph is geared toward advanced undergraduates and graduate students. The treatment presupposes some familiarity with sets, groups, rings, and vector spaces. The four-part approach begins with examinations of sets and maps, monoids and groups, categories, and rings. The second part explores unique factorization domains, general module theory, semisimple rings and modules, and Artinian rings. Part three's topics include localization and tensor products, principal ideal domains, and applications of fundamental theorem. The fourth and final part covers algebraic field extensions

  6. Birth Control Ring

    Science.gov (United States)

    ... Right Sport for You Healthy School Lunch Planner Birth Control Ring KidsHealth > For Teens > Birth Control Ring Print A A A What's in ... español Anillo vaginal anticonceptivo What Is It? The birth control ring is a soft, flexible, doughnut-shaped ...

  7. On Weakly Semicommutative Rings*

    Institute of Scientific and Technical Information of China (English)

    CHEN WEI-XING; CUI SHU-YING

    2011-01-01

    A ring R is said to be weakly scmicommutative if for any a, b ∈ R,ab = 0 implies aRb C_ Nil(R), where Nil(R) is the set of all nilpotcnt elements in R.In this note, we clarify the relationship between weakly semicommutative rings and NI-rings by proving that the notion of a weakly semicommutative ring is a proper generalization of NI-rings. We say that a ring R is weakly 2-primal if the set of nilpotent elements in R coincides with its Levitzki radical, and prove that if R is a weakly 2-primal ring which satisfies oα-condition for an endomorphism α of R (that is, ab = 0 (←→) aα(b) = 0 where a, b ∈ R) then the skew polynomial ring R[π; αα]is a weakly 2-primal ring, and that if R is a ring and I is an ideal of R such that I and R/I are both weakly semicommutative then R is weakly semicommutative.Those extend the main results of Liang et al. 2007 (Taiwanese J. Math., 11(5)(2007),1359-1368) considerably. Moreover, several new results about weakly semicommutative rings and NI-rings are included.

  8. The application of very high resolution satellite image in urban vegetation cover investigation: a case study of Xiamen City%应用高精度卫星图像进行城市植被覆盖调查:以厦门市为例

    Institute of Scientific and Technical Information of China (English)

    程承旗; 李滨; 马廷

    2003-01-01

    With the technological improvements of satellite sensors, we will acquire more informationabout the earth so that we have reached a new application epoch of observation on earthenvironmental change and cartography. But with the enhancement of spatial resolution, somequestions have arisen in the application of using traditional image processing and classificationmethods. Aiming for such questions, we studied the application of IKONOS very high resolutionimage (1 m) in Xiamen City on Urban Vegetation Cover Investigation and discussed the differencebetween the very high resolution image and traditional low spatial resolution image at classification,information abstraction etc. It is an advantageous test for the large-scale application of very highresolution data in the future.

  9. Satellite Geomagnetism

    DEFF Research Database (Denmark)

    Olsen, Nils; Stolle, Claudia

    2012-01-01

    Observations of Earth’s magnetic field from space began more than 50 years ago. A continuous monitoring of the field using low Earth orbit (LEO) satellites, however, started only in 1999, and three satellites have taken highprecision measurements of the geomagnetic field during the past decade...... ability to characterize and understand the many sources that contribute to Earth’s magnetic field. In this review, we summarize investigations of Earth’s interior and environment that have been possible through the analysis of high-precision magnetic field observations taken by LEO satellites........ The unprecedented time-space coverage of their data opened revolutionary new possibilities for monitoring, understanding, and exploring Earth’s magnetic field. In the near future, the three-satellite constellation Swarm will ensure continuity of such measurement and provide enhanced possibilities to improve our...

  10. Satellite (Natural)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    In its most general sense, any celestial object in orbit around a similar larger object. Thus, for example, the Magellanic Clouds are satellite galaxies of our own Milky Way galaxy. Without qualification, the term is used to mean a body in orbit around a planet; an alternative term is moon. The term natural satellite distinguishes these bodies from artificial satellites—spacecraft placed in orbi...

  11. Dust Sources of Saturn's E Ring

    Science.gov (United States)

    Spahn, F.; Schmidt, J.; Albers, N.; Kempf, S.; Krivov, A. V.; Sremcevic, M.

    The recent detection of a dust plume at Enceladus' south pole sheds new light on the origin of the E ring of Saturn. The particles probably condense from gas vents escaping from a system of cracks covering the south pole that appears unusually hot in the Cassini infrared experiments. The main fraction of the E ring dust is created in these gas vents. Still, significant amounts of dust should originate from grains ejected by hypervelocity impacts of E ring particles (ERPs), or alternatively, of interplanetary dust grains (IDPs) on the Saturnian moons embedded in the E ring. We estimate the contributions of impactor -ejecta created dust at these various satellites in the ring, relative to the production rate of grains in the plume at Enceladus. Furthermore, we compare the amount of dust created by both projectile families - ERPs and IDPs - and predict that one can clearly discriminate between the ejecta raised by either projectile families in the data of the Cassini dust detector (CDA) collected at close flybys with the moons embedded in the E ring.

  12. Physics of quantum rings

    CERN Document Server

    Fomin, Vladimir M

    2013-01-01

    This book deals with a new class of materials, quantum rings. Innovative recent advances in experimental and theoretical physics of quantum rings are based on the most advanced state-of-the-art fabrication and characterization techniques as well as theoretical methods. The experimental efforts allow to obtain a new class of semiconductor quantum rings formed by capping self-organized quantum dots grown by molecular beam epitaxy. Novel optical and magnetic properties of quantum rings are associated with non-trivial topologies at the nanoscale. An adequate characterization of quantum rings is po

  13. Envelopes of Commutative Rings

    Institute of Scientific and Technical Information of China (English)

    Rafael PARRA; Manuel SAOR(I)N

    2012-01-01

    Given a significative class F of commutative rings,we study the precise conditions under which a commutative ring R has an F-envelope.A full answer is obtained when.F is the class of fields,semisimple commutative rings or integral domains.When F is the class of Noetherian rings,we give a full answer when the Krull dimension of R is zero and when the envelope is required to be epimorphic.The general problem is reduced to identifying the class of non-Noetherian rings having a monomorphic Noetherian envelope,which we conjecture is the empty class.

  14. RING PROXY SIGNATURES

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Proxy signatures have been used to enable the transfer of digital signing power within some context and ring signatures can be used to provide the anonymity of a signer. By combining the functionalities of proxy signatures and ring signatures, this paper introduces a new concept, named ring proxy signature, which is a proxy signature generated by an anonymous member from a set of potential signers. The paper also constructs the first concrete ring proxy signature scheme based on the provably secure Schnorr's signatures and two ID-based ring proxy signature schemes. The security analysis is provided as well.

  15. On the shepherding of Uranian epsilon ring

    Institute of Scientific and Technical Information of China (English)

    周济林; 孙义燧; Bambi; Hu

    2000-01-01

    To explain the long-term existence of Uranian narrow rings, we study the dynamical evolution of Uranian epsilon ring under the influence of its two shepherding satellites: Cordelia and Ophelia. The model of planar-elliptic restricted three-body problem is employed, in which the three bodies are Uran, a satellite and a test partide. Dissipations due to irrterparticle collisions are also taken into consideration. A mapping system has been obtained based on the differential equation system . Numerical results show that only those partides originally lying in the libration region of the reso-nance can be shepherded. The size of the libration region depends mainly on the orbital eccentricity and mass of the shepherd satellite. For the outer shepherd Ophelia with larger orbital eccentricity, if its mass is a third of the nominal mass 2.5 > 1019 g, most of the orbits are regular and the outer edge of the ring can be shepherded, but more fuzzy than the inner edge. Thus we infer that Ophelia has a smaller mass.

  16. The contraceptive vaginal ring.

    Science.gov (United States)

    Edwardson, Jill; Jamshidi, Roxanne

    2010-03-01

    The contraceptive vaginal ring offers effective contraception that is self-administered, requires less frequent dosing than many other forms of contraception, and provides low doses of hormones. NuvaRing (Organon, Oss, The Netherlands), the only contraceptive vaginal ring approved for use in the United States, contains etonogestrel and ethinyl estradiol. It is inserted into the vagina for 3 weeks, followed by a 1-week ring-free period, and works by inhibiting ovulation. Most women note a beneficial effect on bleeding profiles and are satisfied with NuvaRing. Commonly reported adverse events include vaginitis, leukorrhea, headaches, and device-related events such as discomfort. Serious adverse events are rare. In Chile and Peru, progesterone-only vaginal contraceptive rings are available for nursing women. Studies are ongoing examining new formulations of vaginal contraceptive rings.

  17. New Dust Belts of Uranus: One Ring, Two Ring, Red Ring, Blue Ring

    Energy Technology Data Exchange (ETDEWEB)

    de Pater, I; Hammel, H B; Gibbard, S G; Showalter, M R

    2006-02-02

    We compare near-infrared observations of the recently discovered outer rings of Uranus with HST results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced via impacts into the embedded moon Mab, which apparently orbits at a location where non-gravitational perturbations favor the survival and spreading of sub-micron sized dust. R/2003 U 2 more closely resembles Saturn's G ring.

  18. Certain near-rings are rings, II

    Directory of Open Access Journals (Sweden)

    Howard E. Bell

    1986-01-01

    Full Text Available We investigate distributively-generated near-rings R which satisfy one of the following conditions: (i for each x,y∈R, there exist positive integers m, n for which xy=ymxn; (ii for each x,y∈R, there exists a positive integer n such that xy=(yxn. Under appropriate additional hypotheses, we prove that R must be a commutative ring.

  19. INSTANT CITY

    DEFF Research Database (Denmark)

    Marling, Gitte; Kiib, Hans

    2013-01-01

    experiments are taking place in ‘the instant city’, and how can it be characterized? It also emphasizes the relation between city life, urban design, and the aesthetics of architecture and urban spaces. The question here is, in what way architecture and urban scenography are used as tools to support the goal...... emphasis has been laid on creating a vivid, and engaging social environment in order to create a lab for social, and architectural experi- ments. These goals challenge the city planning as well as the urban sce- nography. The article addresses the research questions: What kind of city life and social...... of an experimental and social en- gaged city environment? The analysis shows that the specific city life at the instant city, Roskilde Festival, can be characterized by being ‘open minded’, ‘playful’ and ‘inclusive’, but also by ‘a culture of laughter’ that penetrates the aesthetics and the urban scenography....

  20. Eating Cities

    DEFF Research Database (Denmark)

    Mikkelsen, Bent Egberg; Fisker, Anna Marie; Clausen, Katja Seerup

    2016-01-01

    This paper analyzed the development of a city based sustainable food strategy for the city of Aalborg. It’s based on 3 cases of food service: food for the elderly as operated by the Municipality, food the hospital patients as operated by the region and food for defense staff as operated by the st......This paper analyzed the development of a city based sustainable food strategy for the city of Aalborg. It’s based on 3 cases of food service: food for the elderly as operated by the Municipality, food the hospital patients as operated by the region and food for defense staff as operated...

  1. Leading Cities

    DEFF Research Database (Denmark)

    Pogner, Karl-Heinz

    2017-01-01

    and technical engineering; Smart Cities) is very prominent in the traditional mass media discourse, in PR / PA of tech companies and traditional municipal administrations; whereas the second one (participation; Livable Cities) is mostly enacted in social media, (local) initiatives, movements, (virtual......) communities, new forms of urban governance in municipal administration and co-competitive city networks. Both forms seem to struggle for getting voice and power in the discourses, negotiations, struggles, and conflicts in Urban Governance about the question how to manage or lead (in) a city. Talking about...

  2. How Prometheus creates structure in Saturn's F ring.

    Science.gov (United States)

    Murray, Carl D; Chavez, Carlos; Beurle, Kevin; Cooper, Nick; Evans, Michael W; Burns, Joseph A; Porco, Carolyn C

    2005-10-27

    Images of Saturn's narrow and contorted F ring returned by the Cassini spacecraft have revealed phenomena not previously detected in any planetary ring system. The perturbing effect of the inner shepherding satellite, Prometheus, seems to introduce channels through the F ring and a 'streamer'--a line of particles that link the ring to the satellite. The detailed mechanism for the formation of these features has been lacking an explanation. Here we show that these phenomena can be understood in terms of a simple gravitational interaction as Prometheus approaches and recedes from the F ring every 14.7 hours. Our numerical models show that as Prometheus recedes from its closest approach to the F ring, it draws out ring material; one orbital period later, this affected region has undergone keplerian shear and is visible as a channel, in excellent agreement with structures seen in the Cassini images. Prometheus' periodic disruption of the F ring will become more pronounced as the two orbits approach their minimum separation in 2009. The model predicts that the appearance of streamers and the associated channels will vary in a regular fashion on a timescale of one orbital period.

  3. On Exchange QB∞-Rings

    Institute of Scientific and Technical Information of China (English)

    Huanyin Chen

    2007-01-01

    In this paper, we introduce a new class of rings, the QB∞-rings. We investigate necessary and sufficient conditions under which an exchange ring is a QB∞-ring. The modules over an exchange QB∞-ring are studied. Also, we prove that every regular square matrix over an exchange QB∞-ring admits a diagonal reduction by pseudo-invertible matrices.

  4. Neutrosophic LA-Semigroup Rings

    Directory of Open Access Journals (Sweden)

    Mumtaz Ali

    2015-01-01

    Full Text Available Neutrosophic LA-semigroup is a midway structure between a neutrosophic groupoid and a commutative neutrosophic semigroup. Rings are the old concept in algebraic structures. We combine the neutrosophic LA-semigroup and ring together to form the notion of neutrosophic LA-semigroup ring. Neutrosophic LAsemigroup ring is defined analogously to neutrosophic group ring and neutrosophic semigroup ring.

  5. Atypical Cities

    Science.gov (United States)

    DiJulio, Betsy

    2011-01-01

    In this creative challenge, Surrealism and one-point perspective combine to produce images that not only go "beyond the real" but also beyond the ubiquitous "imaginary city" assignment often used to teach one-point perspective. Perhaps the difference is that in the "atypical cities challenge," an understanding of one-point perspective is a means…

  6. Soft Cities

    DEFF Research Database (Denmark)

    Brix, Anders; Yoneda, Akira; Nakamura, Kiyoshi

    2015-01-01

    of a sustainable future. The project is the result of a joint research study between Denmark and Japan. Taking as its example the city of Kyoto, the project investigates some possible strategies on how cities more generally may be transformed into liveable, healthy and ecologically sensible environments....

  7. Scientific Satellites

    Science.gov (United States)

    1967-01-01

    followed Hale’s into orbit. In 1879, Jules Verne wrote about launching small satellites with a gun possessing a muzzle velocity of 10 000 m/sec (ref. 3...was activated in 1950.11 It was located only a few tens of miles from the spot where Jules Verne had his Baltimore Gun Club fire a manned projectile to...principle, satellites can be launched by a single impulse applied at the Earth’s surface-say, with a large cannon, & la Jules Verne (sec. 8-3). In

  8. Gulf ring algae

    Science.gov (United States)

    Although they rank among the tiniest of the microspcopic phytoplankton, coccolithophore algae aid oceanographers studying the Gulf Stream rings and the ring boundaries. The algal group could help to identify more precisely the boundary of the warm rings of water that spin off from the Gulf Stream and become independent pools of warm water in the colder waters along the northeastern U.S. coast.Coccolithophore populations in the Gulf Stream rings intrigue oceanographers for two reasons: The phytoplankton are subjected to an environment that changes every few days, and population explosions within one coccolithophore species seem to be associated with changes in the characteristics of ocean water, said Pat Blackwelder, an associate professor at the Nova Oceanographic Center in Dania, Fla. She is one of many studying the physics, chemistry, and biology of warm core rings. A special oceanography session on these rings was held at the recent AGU Fall Meeting/ASLO Winter Meeting.

  9. Token Ring Project

    Directory of Open Access Journals (Sweden)

    Adela Ionescu

    2007-01-01

    Full Text Available Ring topology is a simple configuration used to connect processes that communicate among themselves. A number of network standards such as token ring, token bus, and FDDI are based on the ring connectivity. This article will develop an implementation of a ring of processes that communicate among themselves via pipe links. The processes are nodes in the ring. Each process reads from its standard input and writes in its standard output. N-1 process redirects the its standard output to a standard input of the process through a pipe. When the ring-structure is designed, the project can be extended to simulate networks or to implement algorithms for mutual exclusion

  10. INSTANT CITY

    DEFF Research Database (Denmark)

    Marling, Gitte; Kiib, Hans

    2013-01-01

    experiments are taking place in ‘the instant city’, and how can it be characterized? It also emphasizes the relation between city life, urban design, and the aesthetics of architecture and urban spaces. The question here is, in what way architecture and urban scenography are used as tools to support the goal...... of an experimental and social en- gaged city environment? The analysis shows that the specific city life at the instant city, Roskilde Festival, can be characterized by being ‘open minded’, ‘playful’ and ‘inclusive’, but also by ‘a culture of laughter’ that penetrates the aesthetics and the urban scenography.......This article analyses Roskilde Festival as an Instant City. For more than 40 years, Roskilde Festival has had many thousands participants for a weeklong festival on music, performances and cultural experiences in a layout designed as an urban environment. During the last ten years, in- creasing...

  11. Evaluating NOx Emissions Using Satellite Observations

    Science.gov (United States)

    Frost, G. J.; Kim, S.; Brioude, J.; McKeen, S. A.; Trainer, M.; Heckel, A.; Hilboll, A.; Richter, A.; Burrows, J. P.; Gleason, J. F.; Boersma, K. F.; Hsie, E.; Lee, S.; Angevine, W. M.; Granier, C.; Peischl, J.; Ryerson, T. B.; Fehsenfeld, F. C.

    2012-12-01

    Atmospheric NO2 columns retrieved from satellites can provide a useful top-down assessment of bottom-up NOx emissions inventories. We present three case studies of an approach to evaluate NOx emissions at a sector level by comparing satellite retrievals to regional chemical-transport model calculations of NO2 columns. In the first example, the atmospheric impact of implementing NOx controls at eastern US power plants is demonstrated. In the second study, we use NOx monitors at western US power plants to calibrate our satellite-model comparisons. We then apply our approach to evaluate bottom-up estimates of NOx emissions from western US cities. In the third example, we validate our satellite-model approach using in-situ aircraft measurements and assess NOx emissions from power plants, cities, industrial facilities, and ports in eastern Texas. We conclude with some general insights on the usefulness of this approach and suggestions for future areas of research.

  12. 基于通信卫星的非对称圆环毫米波微带天线%Asymmetric ring millimeter-wave microstrip antenna based on communications satellite

    Institute of Scientific and Technical Information of China (English)

    张宁; 张霞

    2013-01-01

    针对毫米波微带天线的特点,设计了一种可用于通信卫星的天线.该天线在辐射贴片的顶部开了个渐变的缝隙并在天线体上方放置矩形槽形成耦合,从而达到展宽天线带宽的效果,在天线单元的基础上分析了该天线的阵列形式.采用基于时域有限积分算法的CST三维电磁仿真软件对该设计进行仿真,分析结果表明在设计的工作频带范围内,该天线具有较好的带宽范围和较高的增益,且结构小巧简单,具有较高实用价值.%An antenna for communications satellites based on characteristics of millimeter wave microstrip antenna is researched.To broadening the bandwidth,the antenna opened a gradient in the gap at the top of the radiation patch and at the top of the antenna body placed rectangular groove where is formed coupling.Analysis on the basis of the antenna elements,the antenna array have achieved.Simulation of the design using 3D electromagnetic simulation software CST which is used on time domain finite integration algorithm,the analysis results show that in the design of the work within the frequency range the antenna having a better bandwidth range,high directional gain,simple structure and easy to be fabricated in the design band.

  13. Dusty plasma (Yukawa) rings

    CERN Document Server

    Sheridan, T E

    2010-01-01

    One-dimensional and quasi-one-dimensional strongly-coupled dusty plasma rings have been created experimentally. Longitudinal (acoustic) and transverse (optical) dispersion relations for the 1-ring were measured and found to be in very good agreement with the theory for an unbounded straight chain of particles interacting through a Yukawa (i.e., screened Coulomb or Debye-H\\"uckel) potential. These rings provide a new system in which to study one-dimensional and quasi-one-dimensional physics.

  14. Token ring technology report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. This report provides an overview of the IBM Token-Ring technology and products built by IBM and compatible vendors. It consists of two sections: 1. A summary of the design trade-offs for the IBM Token-Ring. 2. A summary of the products of the major token-ring compatible vendors broken down by adapters and components, wiring systems, testing, and new chip technology.

  15. On -Coherent Endomorphism Rings

    Indian Academy of Sciences (India)

    Li-Xin Mao

    2008-11-01

    A ring is called right -coherent if every principal right ideal is finitely presented. Let $M_R$ be a right -module. We study the -coherence of the endomorphism ring of $M_R$. It is shown that is a right -coherent ring if and only if every endomorphism of $M_R$ has a pseudokernel in add $M_R; S$ is a left -coherent ring if and only if every endomorphism of $M_R$ has a pseudocokernel in add $M_R$. Some applications are given.

  16. Physics of quantum rings

    Energy Technology Data Exchange (ETDEWEB)

    Fomin, Vladimir M. (ed.) [Leibniz Institute for Solid State and Materials Research, Dresden (Germany)

    2014-07-01

    Presents the new class of materials of quantum rings. Provides an elemental basis for low-cost high-performance devices promising for electronics, optoelectronics, spintronics and quantum information processing. Explains the physical properties of quantum rings to cover a gap in scientific literature. Presents the application of most advanced nanoengineering and nanocharacterization techniques. This book deals with a new class of materials, quantum rings. Innovative recent advances in experimental and theoretical physics of quantum rings are based on the most advanced state-of-the-art fabrication and characterization techniques as well as theoretical methods. The experimental efforts allow to obtain a new class of semiconductor quantum rings formed by capping self-organized quantum dots grown by molecular beam epitaxy. Novel optical and magnetic properties of quantum rings are associated with non-trivial topologies at the nanoscale. An adequate characterization of quantum rings is possible on the basis of modern characterization methods of nanostructures, such as Scanning Tunneling Microscopy. A high level of complexity is demonstrated to be needed for a dedicated theoretical model to adequately represent the specific features of quantum rings. The findings presented in this book contribute to develop low-cost high-performance electronic, spintronic, optoelectronic and information processing devices based on quantum rings.

  17. Synthesis of Volumetric Ring Antenna Array for Terrestrial Coverage Pattern

    Directory of Open Access Journals (Sweden)

    Alberto Reyna

    2014-01-01

    Full Text Available This paper presents a synthesis of a volumetric ring antenna array for a terrestrial coverage pattern. This synthesis regards the spacing among the rings on the planes X-Y, the positions of the rings on the plane X-Z, and uniform and concentric excitations. The optimization is carried out by implementing the particle swarm optimization. The synthesis is compared with previous designs by resulting with proper performance of this geometry to provide an accurate coverage to be applied in satellite applications with a maximum reduction of the antenna hardware as well as the side lobe level reduction.

  18. Synthesis of Volumetric Ring Antenna Array for Terrestrial Coverage Pattern

    Science.gov (United States)

    Reyna, Alberto; Panduro, Marco A.; Del Rio Bocio, Carlos

    2014-01-01

    This paper presents a synthesis of a volumetric ring antenna array for a terrestrial coverage pattern. This synthesis regards the spacing among the rings on the planes X-Y, the positions of the rings on the plane X-Z, and uniform and concentric excitations. The optimization is carried out by implementing the particle swarm optimization. The synthesis is compared with previous designs by resulting with proper performance of this geometry to provide an accurate coverage to be applied in satellite applications with a maximum reduction of the antenna hardware as well as the side lobe level reduction. PMID:24701150

  19. Ring Around a Galaxy

    Science.gov (United States)

    1999-01-01

    Space Telescope Science Institute astronomers are giving the public chances to decide where to aim NASA's Hubble Space Telescope. Guided by 8,000 Internet voters, Hubble has already been used to take a close-up, multi-color picture of the most popular object from a list of candidates, the extraordinary 'polar-ring' galaxy NGC 4650A. Located about 130 million light-years away, NGC 4650A is one of only 100 known polar-ring galaxies. Their unusual disk-ring structure is not yet understood fully. One possibility is that polar rings are the remnants of colossal collisions between two galaxies sometime in the distant past, probably at least 1 billion years ago. What is left of one galaxy has become the rotating inner disk of old red stars in the center. Meanwhile, another smaller galaxy which ventured too close was probably severely damaged or destroyed. The bright bluish clumps, which are especially prominent in the outer parts of the ring, are regions containing luminous young stars, examples of stellar rebirth from the remnants of an ancient galactic disaster. The polar ring appears to be highly distorted. No regular spiral pattern stands out in the main part of the ring, and the presence of young stars below the main ring on one side and above on the other shows that the ring is warped and does not lie in one plane. Determining the typical ages of the stars in the polar ring is an initial goal of our Polar Ring Science Team that can provide a clue to the evolution of this unusual galaxy. The HST exposures were acquired by the Hubble Heritage Team, consisting of Keith Noll, Howard Bond, Carol Christian, Jayanne English, Lisa Frattare, Forrest Hamilton, Anne Kinney and Zolt Levay, and guest collaborators Jay Gallagher (University of Wisconsin-Madison), Lynn Matthews (National Radio Astronomy Observatory-Charlottesville), and Linda Sparke (University of Wisconsin-Madison).

  20. Perturbations to Saturn's F-ring strands at their closest approach to Prometheus

    Science.gov (United States)

    Giuliatti, Winter S.M.; Murray, C.D.; Gordon, M.

    2000-01-01

    The strange morphology of the F ring of Saturn is thought to be caused by the perturbing effects of two close satellites, Prometheus and Pandora. The F ring and the satellites also experience periodic close encounters as a result of differential precession arising from Saturn's oblateness. Using the orbits of the F-ring strands derived by Murray et al. (1997, Icarus 129, 304-316) the behaviour of the ring particles at their closest approach to Prometheus is analysed using numerical simulations. The results show that a gap and a wave are formed in the ring at each encounter with the satellite. However, the gap is expected to have a short lifetime due to keplerian shear. ?? 2000 Elsevier Science Ltd. All rights reserved.

  1. Flying Cities

    DEFF Research Database (Denmark)

    Herbelin, Bruno; Lasserre, Sebastien; Ciger, Jan

    2008-01-01

    . This cross-modal interaction not only supports our artistic messages, but also aims at providing anyone with a pleasant and stimulating feedback from her/his speech activity. As the feedback we have received when presenting Flying Cities was very positive, our objective is now to cross the bridge between art......Flying Cities is an artistic installation which generates imaginary cities from the speech of its visitors. Thanks to an original interactive process analyzing people's vocal input to create 3D graphics, a tangible correspondence between speech and visuals opens new possibilities of interaction...

  2. City Branding

    DEFF Research Database (Denmark)

    Frimann, Søren; Stigel, Jørgen

    2006-01-01

    with their relatively concrete dimensions are absent when the main question is one of values. Furthermore, when  the relatively straightforward identification and power structures of corporations and consumers are replaced by the more diversified structures of city government, their poplulations, and potential visitors......, problems seem to multiply in what has becom known as city branding. This analysis of the communicational aspects of two Danish provincial towns´ branding efforts examines both their internally and externally directed communication. It demonstrates that an insufficient understanding of - or willingness...... to face - these differences will inevitably hamper such branding efforts because of the consequential inconsistencies. Finally, paths to more effective city branding are indicated...

  3. Sin City?

    DEFF Research Database (Denmark)

    Svarer, Michael; Gautier, Pieter A.; Teulings, Coen n.

    , the ones who stay in the city have significant higher divorce rates. Similarly, for the couples who married outside the city, the ones who move to the city are more likely to divorce. This correlation can be explained by both a causal and a sorting effect. We disentangle them by using the timing......-of-events approach. In addition we use information on father's location as an instrument. We find that the sorting effect dominates. Moving to the countryside is therefore not a cheap way to prolong relationships....

  4. Cassini discovers a kinematic spiral ring around Saturn.

    Science.gov (United States)

    Charnoz, S; Porco, C C; Déau, E; Brahic, A; Spitale, J N; Bacques, G; Baillie, K

    2005-11-25

    Since the time of the Voyager flybys of Saturn in 1980-1981, Saturn's eccentric F ring has been known to be accompanied on either side by faint strands of material. New Cassini observations show that these strands, initially interpreted as concentric ring segments, are in fact connected and form a single one-arm trailing spiral winding at least three times around Saturn. The spiral rotates around Saturn with the orbital motion of its constituent particles. This structure is likely the result of differential orbital motion stretching an initial cloud of particles scattered from the dense core of the F ring. Different scenarios of formation, implying ringlet-satellite interactions, are explored. A recently discovered moon candidate, S/2004 S6, is on an orbit that crosses the F-ring core at the intersection of the spiral with the ring, which suggests a dynamical connection between S/2004 S6 and the spiral.

  5. Algorithms for finite rings

    NARCIS (Netherlands)

    Ciocanea Teodorescu I.,

    2016-01-01

    In this thesis we are interested in describing algorithms that answer questions arising in ring and module theory. Our focus is on deterministic polynomial-time algorithms and rings and modules that are finite. The first main result of this thesis is a solution to the module isomorphism problem in

  6. Revocable Ring Signature

    Institute of Scientific and Technical Information of China (English)

    Dennis Y. W. Liu; Joseph K. Liu; Yi Mu; Willy Susilo; Duncan S. Wong

    2007-01-01

    Group signature allows the anonymity of a real signer in a group to be revoked by a trusted party called group manager. It also gives the group manager the absolute power of controlling the formation of the group. Ring signature, on the other hand, does not allow anyone to revoke the signer anonymity, while allowing the real signer to forma group (also known as a ring) arbitrarily without being controlled by any other party. In this paper, we propose a new variant for ring signature, called Revocable Ring Signature. The signature allows a real signer to form a ring arbitrarily while allowing a set of authorities to revoke the anonymity of the real signer. This new variant inherits the desirable properties from both group signature and ring signature in such a way that the real signer will be responsible for what it has signed as the anonymity is revocable by authorities while the real signer still has the freedom on ring formation. We provide a formal security model for revocable ring signature and propose an efficient construction which is proven secure under our security model.

  7. Illustration of Saturn's Rings

    Science.gov (United States)

    2001-01-01

    This illustration shows a close-up of Saturn's rings. These rings are thought to have formed from material that was unable to form into a Moon because of tidal forces from Saturn, or from a Moon that was broken up by Saturn's tidal forces.

  8. The Fermilab recycler ring

    Energy Technology Data Exchange (ETDEWEB)

    Martin Hu

    2001-07-24

    The Fermilab Recycler is a permanent magnet storage ring for the accumulation of antiprotons from the Antiproton Source, and the recovery and cooling of the antiprotons remaining at the end of a Tevatron store. It is an integral part of the Fermilab III luminosity upgrade. The following paper describes the design features, operational and commissioning status of the Recycler Ring.

  9. EBT ring physics

    Energy Technology Data Exchange (ETDEWEB)

    Uckan, N.A. (ed.)

    1980-04-01

    This workshop attempted to evaluate the status of the current experimental and theoretical understanding of hot electron ring properties. The dominant physical processes that influence ring formation, scaling, and their optimal behavior are also studied. Separate abstracts were prepared for each of the 27 included papers. (MOW)

  10. Smoke Ring Physics

    Science.gov (United States)

    Huggins, Elisha

    2011-01-01

    The behavior of smoke rings, tornados, and quantized vortex rings in superfluid helium has many features in common. These features can be described by the same mathematics we use when introducing Ampere's law in an introductory physics course. We discuss these common features. (Contains 7 figures.)

  11. Algorithms for finite rings

    NARCIS (Netherlands)

    Ciocanea Teodorescu I.,

    2016-01-01

    In this thesis we are interested in describing algorithms that answer questions arising in ring and module theory. Our focus is on deterministic polynomial-time algorithms and rings and modules that are finite. The first main result of this thesis is a solution to the module isomorphism problem in

  12. Planetary rings - Theory

    Science.gov (United States)

    Borderies, Nicole

    1989-01-01

    Theoretical models of planetary-ring dynamics are examined in a brief analytical review. The mathematical description of streamlines and streamline interactions is outlined; the redistribution of angular momentum due to collisions between particles is explained; and problems in the modeling of broad, narrow, and arc rings are discussed.

  13. Steroidal contraceptive vaginal rings.

    Science.gov (United States)

    Sarkar, N N

    2003-06-01

    The development of steroid-releasing vaginal rings over the past three decades is reviewed to illustrate the role of this device as an effective hormonal contraceptive for women. Vaginal rings are made of polysiloxane rubber or ethylene-vinyl-acetate copolymer with an outer diameter of 54-60 mm and a cross-sectional diameter of 4-9.5 mm and contain progestogen only or a combination of progestogen and oestrogen. The soft flexible combined ring is inserted in the vagina for three weeks and removed for seven days to allow withdrawal bleeding. Progesterone/progestogen-only rings are kept in for varying periods and replaced without a ring-free period. Rings are in various stages of research and development but a few, such as NuvaRing, have reached the market in some countries. Women find this method easy to use, effective, well tolerated and acceptable with no serious side-effects. Though the contraceptive efficacy of these vaginal rings is high, acceptability is yet to be established.

  14. Jupiter's Rings: Sharpest View

    Science.gov (United States)

    2007-01-01

    The New Horizons spacecraft took the best images of Jupiter's charcoal-black rings as it approached and then looked back at Jupiter. The top image was taken on approach, showing three well-defined lanes of gravel- to boulder-sized material composing the bulk of the rings, as well as lesser amounts of material between the rings. New Horizons snapped the lower image after it had passed Jupiter on February 28, 2007, and looked back in a direction toward the sun. The image is sharply focused, though it appears fuzzy due to the cloud of dust-sized particles enveloping the rings. The dust is brightly illuminated in the same way the dust on a dirty windshield lights up when you drive toward a 'low' sun. The narrow rings are confined in their orbits by small 'shepherding' moons.

  15. City Streets

    Data.gov (United States)

    Minnesota Department of Natural Resources — This data set contains roadway centerlines for city streets found on the USGS 1:24,000 mapping series. In some areas, these roadways are current through the 2000...

  16. City Branding

    DEFF Research Database (Denmark)

    Frimann, Søren; Stigel, Jørgen

    2006-01-01

    with their relatively concrete dimensions are absent when the main question is one of values. Furthermore, when  the relatively straightforward identification and power structures of corporations and consumers are replaced by the more diversified structures of city government, their poplulations, and potential visitors...... to face - these differences will inevitably hamper such branding efforts because of the consequential inconsistencies. Finally, paths to more effective city branding are indicated...

  17. Model cities

    OpenAIRE

    Batty, M.

    2007-01-01

    The term ?model? is now central to our thinking about how weunderstand and design cities. We suggest a variety of ways inwhich we use ?models?, linking these ideas to Abercrombie?sexposition of Town and Country Planning which represented thestate of the art fifty years ago. Here we focus on using models asphysical representations of the city, tracing the development ofsymbolic models where the focus is on simulating how functiongenerates form, to iconic models where the focus is on representi...

  18. Earth: A Ringed Planet?

    Science.gov (United States)

    Hancock, L. O.; Povenmire, H.

    2010-12-01

    Among the most beautiful findings of the Space Age have been the discoveries of planetary rings. Not only Saturn but also Jupiter, Uranus and Neptune have rings; Saturn’s ring system has structures newly discovered; even Saturn's moon Rhea itself has a ring. All these are apparently supplied by material from the planetary moons (Rhea's ring by Rhea itself). The question naturally arises, why should the Earth not have a ring, and on the other hand, if it does, why has it not been observed? No rings have yet been observed in the inner solar system, but after all, rings in the inner solar system might simply tend to be fainter and more transient than those of the outer solar system: the inner solar system is more affected by the solar wind, and the Sun’s perturbing gravitational influence is greater. J.A. O’Keefe first suggested (1980) that Earth might have a ring system of its own. An Earth ring could account for some climate events. O’Keefe remarked that formation or thickening of a ring system in Earth’s equatorial plane could drive glaciation by deepening the chill of the winter hemisphere. (It is very well established that volcanic dust is an effective agent for the extinction of sunlight; this factor can be overwhelmingly apparent in eclipse observations.) O’Keefe died in 2000 and the speculation was not pursued, but the idea of an Earth ring has a prima facie reasonableness that calls for its renewed consideration. The program of this note is to hypothesize that, as O’Keefe proposed: (a) an Earth ring system exists; (b) it affects Earth's weather and climate; (c) the tektite strewn fields comprise filaments of the ring fallen to Earth's surface on various occasions of disturbance by comets or asteroids. On this basis, and drawing on the world's weather records, together with the Twentieth Century Reanalysis by NCEP/CIRES covering the period 1870-2010 and the geology of the tektite strewn fields, we herein propose the hypothesized Earth ring

  19. Local loop near-rings

    OpenAIRE

    Franetič, Damir

    2015-01-01

    We study loop near-rings, a generalization of near-rings, where the additive structure is not necessarily associative. We introduce local loop near-rings and prove a useful detection principle for localness.

  20. Cassini RSS occultation observations of density waves in Saturn's rings

    Science.gov (United States)

    McGhee, C. A.; French, R. G.; Marouf, E. A.; Rappaport, N. J.; Schinder, P. J.; Anabtawi, A.; Asmar, S.; Barbinis, E.; Fleischman, D.; Goltz, G.; Johnston, D.; Rochblatt, D.

    2005-08-01

    On May 3, 2005, the first of a series of eight nearly diametric occultations by Saturn's rings and atmosphere took place, observed by the Cassini Radio Science (RSS) team. Simultaneous high SNR measurements at the Deep Space Network (DSN) at S, X, and Ka bands (λ = 13, 3.6, and 0.9 cm) have provided a remarkably detailed look at the radial structure and particle scattering behavior of the rings. By virtue of the relatively large ring opening angle (B=-23.6o), the slant path optical depth of the rings was much lower than during the Voyager epoch (B=5.9o), making it possible to detect many density waves and other ring features in the Cassini RSS data that were lost in the noise in the Voyager RSS experiment. Ultimately, diffraction correction of the ring optical depth profiles will yield radial resolution as small as tens of meters for the highest SNR data. At Ka band, the Fresnel scale is only 1--1.5 km, and thus even without diffraction correction, the ring profiles show a stunning array of density waves. The A ring is replete with dozens of Pandora and Prometheus inner Lindblad resonance features, and the Janus 2:1 density wave in the B ring is revealed with exceptional clarity for the first time at radio wavelengths. Weaker waves are abundant as well, and multiple occultation chords sample a variety of wave phases. We estimate the surface mass density of the rings from linear density wave models of the weaker waves. For stronger waves, non-linear models are required, providing more accurate estimates of the wave dispersion relation, the ring surface mass density, and the angular momentum exchange between the rings and satellite. We thank the DSN staff for their superb support of these complex observations.

  1. ELASR – An electrostatic storage ring for atomic and molecular physics at KACST

    Directory of Open Access Journals (Sweden)

    Mohamed O.A. El Ghazaly

    2015-01-01

    Full Text Available A new ELectrostAtic Storage Ring (ELASR has been designed and built at the King Abdulaziz City for Science and Technology (KACST, in Riyadh, Saudi Arabia. It was developed to be the core of a new storage ring laboratory for atomic and molecular physics at KACST. ELASR follows the standard design of the pioneering storage ring ELISA and it thereby features a racetrack single-bend shaped ring. Complementary simulation code packages were used to work out the design under the requirements of the projected experiments. This paper reports a short description of the ELASR storage ring through an overview of its design and construction.

  2. Theodolite Ring Lights

    Science.gov (United States)

    Clark, David

    2006-01-01

    Theodolite ring lights have been invented to ease a difficulty encountered in the well-established optical-metrology practice of using highly reflective spherical tooling balls as position references. A theodolite ring light produces a more easily visible reflection and eliminates the need for an autocollimating device. A theodolite ring light is a very bright light source that is well centered on the optical axis of the instrument. It can be fabricated, easily and inexpensively, for use on a theodolite or telescope of any diameter.

  3. Heavy ion storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Schuch, R.

    1987-01-01

    A brief overview of synchrotron storage rings for heavy ions, which are presently under construction in different accelerator laboratories is given. Ions ranging from protons up to uranium ions at MeV/nucleon energies will be injected into these rings using multiturn injection from the accelerators available or being built in these laboratories. After injection, it is planned to cool the phase space distribution of the ions by merging them with cold electron beams or laser beams, or by using stochastic cooling. Some atomic physics experiments planned for these rings are presented.

  4. Keeping the Edges Sharp I: Honing the Theory of Narrow Rings

    Science.gov (United States)

    Hamilton, Douglas P.; Rimlinger, Thomas; Hahn, Joseph M.

    2016-05-01

    Most of the rings that encircle Saturn, Uranus, and Neptune are very narrow structures with typical radial widths of just a few kilometers. Such extreme sharpness is surprising, as even slightly different orbital periods should allow ring particles to continually jostle one another in collisions that preserve angular momentum whileinexorably draining energy. Sharp edges should blur as rings spread in response to collisions and yet they do not. The generally accepted solution to this dilemma is to bracket each narrow ring with a pair of shepherding satellites that can pump energy back into the ring to replace that lost by collisions. But only a disappointing two of roughly twenty narrow rings actually have known attendant satellites. We present a compelling alternative in which the slight eccentricities and inclinations of narrow ringlets act as internal energy sources that can be tapped to prevent ring spreading. When unattended circular rings dissipate energy they must spread radially in order to preserve angular momentum. By contrast, eccentric or inclined rings have an extra degree of freedom that can be exploited to prevent radial spreading; energy is dissipated while keeping z-component of angular momentum, sqrt(a(1-e^2))cos(i), constant by simply decreasing the overall eccentricity (e) and/or inclination (i) of the entire ring. A real narrow ring moves inward as a unit, circularizes, and drops into the equatorial plane in a process that deters radial spreading for millions or billions of years. Using secular theory with dissipation (Zhang et al. 2013), we show that narrow rings are secular eigenstates in which ellipses are nested with pericenters almost, but not exactly aligned. The misalignment of pericenters is crucial in allowing energy dissipation to be shared evenly across the ring. We predict ring surface densities that are roughly constant across the ring's width, in contrast to profiles expected for shepherded rings. Rimlinger et al. (this meeting

  5. Design of a novel electrostatic ion storage ring at KACST

    Energy Technology Data Exchange (ETDEWEB)

    El Ghazaly, M.O.A., E-mail: maelghazaly@kacst.edu.sa [National Center for Mathematics and Physics (NCMP), King Abdulaziz City for Sciences and Technology (KACST), P.O. Box 6086, Riyadh 11442 (Saudi Arabia); Alshammari, S.M. [National Center for Mathematics and Physics (NCMP), King Abdulaziz City for Sciences and Technology (KACST), P.O. Box 6086, Riyadh 11442 (Saudi Arabia); Welsch, C.P. [Cockcroft Institute and the University of Liverpool (United Kingdom); Alharbi, H.H. [National Center for Mathematics and Physics (NCMP), King Abdulaziz City for Sciences and Technology (KACST), P.O. Box 6086, Riyadh 11442 (Saudi Arabia)

    2013-05-01

    A new electrostatic storage ring for beams at energies up to 30 keV·q is currently under development at the National Centre for Mathematics and Physics (NCMP), King Abdulaziz City for Science and Technology (KACST). The ring design is based on the existing electrostatic storage rings, but stretches significantly beyond them in that it shall form the core of a unique flexible experimental facility at KACST. The lattice of this ring has been designed in a way that enables the use of state-of-the-art experimental methods to study electron–ion, laser-ion, and ion-neutral beams interactions. The lattice design also allows for a future upgrade of the ring to a double storage ring structure that would enable ion–ion beam interactions to be performed. In this paper, we present the design of this ring with a focus on beam dynamics calculations for the 7° single-bend racetrack layout. The study is principally based on the SIMION8 program. We complemented this study further by using purpose-written routine and MAD-X simulation code. An in-depth investigation into beam stability under consideration of non-linear field components in the electrostatic optical elements, is presented. Finally, different working points and stability regions are discussed. -- Highlights: ► The design for a highly flexible electrostatic storage ring is carried out. ► It is shown this design can be upgraded to a double storage ring structure. ► SIMION can be used in ray-tracing simulations to compute aberrations in the ring. ► Non-linear effects in an electrostatic ring can potentially disturb the stored beam. ► An electrostatic ring can store low-energy beams in spite of existing fringe fields.

  6. Drone City

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2016-01-01

    design” will be used as a background perspective to reflect upon the future of drones in cities. The other perspective used to frame the phenomenon is the emerging discourse of the “smart city”. A city of proliferating digital information and data communication may be termed a smart city as shorthand......This paper address the phenomenon of drones and their potential relationship with the city from the point of view of the so-called “mobilities turn”. This is done in such a way that turns attention to a recent redevelopment of the “turn” towards design; so the emerging perspective of “mobilities...... for a new urban condition where cities are networked and connected (as well as disconnected) from the local block to global digital spheres. In the midst of many of the well-known data-creating devices (e.g. Bluetooth, radio-frequency identification (RFID), GPS, smartphone applications) there is a “new kid...

  7. 75 FR 15392 - Satellite License Procedures

    Science.gov (United States)

    2010-03-29

    ... filing instructions for e-mail comments, commenters should send an e-mail to ecfs@fcc.gov , and should... means governments of cities, counties, towns, townships, villages, school districts, or special... read as follows: Sec. 25.211 Analog video transmissions in the Fixed Satellite Services. * * * * * (e...

  8. Ringed Seal Distribution Map

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains GIS layers that depict the known spatial distributions (i.e., ranges) of the five subspecies of ringed seals (Phoca hispida). It was produced...

  9. The g-2 ring

    CERN Multimedia

    1974-01-01

    The precise measurement of "g-2", the anomalous magnetic moment of the muon, required a special muon storage ring with electrostatic focussing and very accurate knowledge of the magnetic bending field. For more details see under photo 7405430.

  10. Modified Newton's rings: II

    CERN Document Server

    Chaitanya, T Sai; Krishna, V Sai; Anandh, B Shankar; Umesh, K S

    2010-01-01

    In an earlier work (Shankar kumar Jha, A Vyas, O S K S Sastri, Rajkumar Jain & K S Umesh, 'Determination of wavelength of laser light using Modified Newton's rings setup', Physics Education, vol. 22, no.3, 195-202(2005)) reported by our group, a version of Newton's rings experiment called Modified Newton's rings was proposed. The present work is an extension of this work. Here, a general formula for wavelength has been derived, applicable for a plane of observation at any distance. A relation between the focal length and the radius curvature is also derived for a plano-convex lens which is essentially used as a concave mirror. Tracker, a video analysis software, freely downloadable from the net, is employed to analyze the fringes captured using a CCD camera. Two beams which give rise to interference fringes in conventional Newton's rings and in the present setup are clearly distinguished.

  11. Spectral properties of icy satellites

    Science.gov (United States)

    Stephan, Katrin; Jaumann, Ralf; Wagner, Roland; Clark, Roger; Cruikshank, Dale; Brown, Robert; Roatsch, Thomas; Buratti, Bonnie; Matson, Dennis; Dalle Ore, Cristina; Filacchione, Gianrico; Capaccioni, Fabrizio; Nicholson, Phil; Baines, Kevin; Sotin, Christoph

    2015-08-01

    Since 2004 Cassini is orbiting the Saturnian system with its instruments investigating the chemical and physical properties of Saturn ‘s atmosphere, its magnetosphere, its numerous satellites and rings. The VIMS instrument onboard Cassini enables not only to identify the Saturn satellites’ compositional units but also to map their distribution across the surfaces, to relate their location and extension to specific geological and/or geomorphological surface features and to characterize surface alterations induced by the space environment. Although, the VIMS spectra of the Saturnian satellites’ surfaces are dominated by H2O-ice, its distribution and physical characteristics differ distinctly from one satellite to the other. Global hemispherical differences are mostly related to the satellite’s orbital position within the Saturnian system, i.e. the distance to Saturn and its E ring, with particles originating from Saturn’s magnetosphere and/or the ice grains coming from the E ring impacting their surfaces. Often, these hemispherical differences are characterized by a dark non-icy contaminant more concentrated on their trailing hemispheres, while the more water ice-rich leading hemispheres appear covered by fresh material ejected by an impact event and/or by impacting E-ring particles. Tethys, however, situated closer to Enceladus and the E ring and deeper within Saturn’s magnetosphere, shows a more complex pattern. Compositional changes on a regional and local scale could be identified and related to the geological processes, i.e. impact cratering, tectonics, and erosion. Particularly, young impact craters and tectonic features reveal clean H2O ice of relatively large grain size while the “fresh” (unaltered) surface material offers a unique view into the crustal properties and evolution of its satellite. Whereas, prominent graben systems on Dione and Rhea are characterized by a pronounced ice signature - Ithaca Chasma on Tethys is barely recognizable

  12. Flying Cities

    DEFF Research Database (Denmark)

    Ciger, Jan

    2006-01-01

    The Flying Cities artistic installation brings to life imaginary cities made from the speech input of visitors. In this article we describe the original interactive process generating real time 3D graphics from spectators' vocal inputs. This example of cross-modal interaction has the nice property...... of providing a tangible correspondence between the two spaces. This interaction mean has proved to suit the artistic expression well but it also aims at providing anyone with a pleasant and stimulating feedback from speech activity, a new medium for creativity and a way to visually perceive a vocal performance....... As the feedback we have received when presenting Flying Cities was very positive, our objective now is to cross the bridge between art and the potential applications to the rehabilitation of people with reduced mobility or for the treatment of language impairments....

  13. Small sized slip-ring capsule endurance testing

    Science.gov (United States)

    Mondier, Jean-Bernard

    2005-07-01

    Slip-ring capsules are mechanical units used to carry electrical signals or power currents through a rotating joint. They are used either in solar array drive mechanisms (SADM) or in scientific instruments like radiometers. Analyses of the latest missions show that the slip-rings requirements are more and more demanding. For example, the number of in-orbit mechanical cycles keeps increasing. As a result, a signal slip-ring technology, which had been successfully tested for a given need, now has to improve its performances. It was therefore interesting to try to reach the slip-rings technical limits by testing them beyond the required performance of already known space missions. Slip-rings units are currently used in mechanisms such as SADM for the CNES Proteus and Myriade satellite family. They can be also found in the payload instruments of the Megha-Tropiques satellite project, namely Madras and Scarab. A selected hardware was tested at the mechanism endurance laboratory of the CNES, in Toulouse. The typical in-orbit rotation speed was increased in order to limit the test duration to 2 years. The main interest of this work was to provide a continuous slip-ring performance status and a large set of engineering data. The main test results are presented and discussed. The following lines also report a part of the hardware detailed inspection and the lessons learned.

  14. The satellite-based remote sensing of particulate matter (PM) in support to urban air quality: PM variability and hot spots within the Cordoba city (Argentina) as revealed by the high-resolution MAIAC-algorithm retrievals applied to a ten-years dataset (2

    Science.gov (United States)

    Della Ceca, Lara Sofia; Carreras, Hebe A.; Lyapustin, Alexei I.; Barnaba, Francesca

    2016-04-01

    Particulate matter (PM) is one of the major harmful pollutants to public health and the environment [1]. In developed countries, specific air-quality legislation establishes limit values for PM metrics (e.g., PM10, PM2.5) to protect the citizens health (e.g., European Commission Directive 2008/50, US Clean Air Act). Extensive PM measuring networks therefore exist in these countries to comply with the legislation. In less developed countries air quality monitoring networks are still lacking and satellite-based datasets could represent a valid alternative to fill observational gaps. The main PM (or aerosol) parameter retrieved from satellite is the 'aerosol optical depth' (AOD), an optical parameter quantifying the aerosol load in the whole atmospheric column. Datasets from the MODIS sensors on board of the NASA spacecrafts TERRA and AQUA are among the longest records of AOD from space. However, although extremely useful in regional and global studies, the standard 10 km-resolution MODIS AOD product is not suitable to be employed at the urban scale. Recently, a new algorithm called Multi-Angle Implementation of Atmospheric Correction (MAIAC) was developed for MODIS, providing AOD at 1 km resolution [2]. In this work, the MAIAC AOD retrievals over the decade 2003-2013 were employed to investigate the spatiotemporal variation of atmospheric aerosols over the Argentinean city of Cordoba and its surroundings, an area where a very scarce dataset of in situ PM data is available. The MAIAC retrievals over the city were firstly validated using a 'ground truth' AOD dataset from the Cordoba sunphotometer operating within the global AERONET network [3]. This validation showed the good performances of the MAIAC algorithm in the area. The satellite MAIAC AOD dataset was therefore employed to investigate the 10-years trend as well as seasonal and monthly patterns of particulate matter in the Cordoba city. The first showed a marked increase of AOD over time, particularly evident in

  15. The life cycle of a coherent Lagrangian Agulhas ring

    CERN Document Server

    Wang, Y; Olascoaga, M J

    2016-01-01

    We document the long-term evolution of an Agulhas ring detected from satellite altimetry using a technique from nonlinear dynamical systems that enables objective (i.e., observer-independent) eddy framing. Such objectively detected eddies have Lagrangian (material) boundaries that remain coherent (unfilamented) over the detection period. The ring preserves a quite compact material entity for a period of about 2 years even after most initial coherence is lost within 5 months after detection. We attribute this to the successive development of short-term coherent material boundaries around the ring. These boundaries provide effective short-term shielding for the ring, which prevents a large fraction of the ring's interior from being mixed with the ambient turbulent flow. We show that such coherence regain events cannot be inferred from Eulerian analysis. This process is terminated by a ring-splitting event which marks the ring demise, near the South American coast. The genesis of the ring is characterized by a r...

  16. Soft Cities

    DEFF Research Database (Denmark)

    Brix, Anders; Yoneda, Akira; Nakamura, Kiyoshi

    2015-01-01

    This paper presents a project exploring sustainable ways of urban living. The project renders a scenario comprised of an array of simple conversions of existing urban spaces and buildings, in the attempt to tie strategies ranging from urban planning to interior design into a coherent vision...... of a sustainable future. The project is the result of a joint research study between Denmark and Japan. Taking as its example the city of Kyoto, the project investigates some possible strategies on how cities more generally may be transformed into liveable, healthy and ecologically sensible environments....

  17. Fun City

    DEFF Research Database (Denmark)

    Once the blues guitarist B.B. King sang that when he "didn't wanna live no more", he would go shopping instead. Now, however, shopping has become a lifestyle... The city of today has become "Disneyfied" and "Tivolized". It has become a scene for events. The aim of the book is to encircle and pin...... down the consquences of these developments, to elocidate the interplay between funscapes and fear culture, and to account for the meaning of new concepts and new phenomena such as "event culture", "urban scenography", "experience economy","city branding" and "cultural planning"....

  18. Unhappy Cities

    Science.gov (United States)

    Glaeser, Edward L.; Gottlieb, Joshua D.; Ziv, Oren

    2016-01-01

    There are persistent differences in self-reported subjective well-being across US metropolitan areas, and residents of declining cities appear less happy than others. Yet some people continue to move to these areas, and newer residents appear to be as unhappy as longer-term residents. While historical data on happiness are limited, the available facts suggest that cities that are now declining were also unhappy in their more prosperous past. These facts support the view that individuals do not maximize happiness alone but include it in the utility function along with other arguments. People may trade off happiness against other competing objectives. PMID:27546979

  19. Flying Cities

    DEFF Research Database (Denmark)

    Ciger, Jan

    2006-01-01

    of providing a tangible correspondence between the two spaces. This interaction mean has proved to suit the artistic expression well but it also aims at providing anyone with a pleasant and stimulating feedback from speech activity, a new medium for creativity and a way to visually perceive a vocal performance......The Flying Cities artistic installation brings to life imaginary cities made from the speech input of visitors. In this article we describe the original interactive process generating real time 3D graphics from spectators' vocal inputs. This example of cross-modal interaction has the nice property...

  20. City 2020+

    Science.gov (United States)

    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

  1. Scheme of Saturn rings origination and nature of the Cassini's division

    Energy Technology Data Exchange (ETDEWEB)

    Davydov, V.D.

    The united solution of two problems: the problem of Cassini division width and the problem of the former Saturn satellite plunging into the tidal destruction zone is suggested on the base of the analysis of observed properties of the Saturn rings. The scheme of the ring system formation is built up; the concrete characteristics of the former satellite from which this system has been formed are found out. The literature data on the Saturn rings observation from the ''Voyadger-1'', ''Voyadger-2'' space probes are used in the paper.

  2. Density waves in Saturn's rings probed by radio and optical occultation - Observational tests of theory

    Science.gov (United States)

    Brophy, Thomas G.; Rosen, Paul A.

    1992-01-01

    A parallel examination is conducted of Voyager radio and photopolarimeter occultation observations of the Saturn A ring's density waves. The radio instrument waves exhibit an average -90 deg offset from the dynamical phase. A warping height of about 100-m amplitude can qualtitatively reproduce this phase shift, while preserving the overall model wave shape. These results may be profoundly relevant for satellite-ring torque calculations in Saturn's rings, given the deposition of all of the net torque of the standard model in the first wavelength.

  3. Descent from the form ring and Buchsbaum rings

    CERN Document Server

    Schenzel, P

    1996-01-01

    There is a spectral sequence technique in order to estimate the local cohomology of a ring by the local cohomology of a certain form ring. As applications there are information on the descent of homological properties (Cohen-Macaulay, Buchsbaum etc.) from the form ring to the ring itself. In the case of Buchsbaum ring there is a discussion of the descent of the surjectivity of a natural map into the local cohomology.

  4. Sin City?

    NARCIS (Netherlands)

    Gautier, Pieter A.; Svarer, Michael; Teulings, Coen N.

    2007-01-01

    Is moving to the countryside a credible commitment device for couples? We investigate whether lowering the arrival rate of potential alternative partners by moving to a less populated area lowers the dissolution risk for a sample of Danish couples. We find that of the couples who married in the city

  5. Excite City

    DEFF Research Database (Denmark)

    Marling, Gitte; Kiib, Hans; Jensen, Ole B.

    This paper takes its point of departure in the pressure of the experience economy on European cities - a pressure which in recent years has found its expression in a number of comprehensive transformations of the physical and architectural environments, and new eventscapes related to fun and cult...

  6. Vacant city

    NARCIS (Netherlands)

    Marzot, N.

    2013-01-01

    Abandoned places that the crisis has multiplied, unaware wrecks of a project of civilization that has consumed its thrust and life-giving function, are waiting for new desirable interpretations, they are an expression of a possible city in opposition to the existing, even if not recognized by any in

  7. Drone City

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2016-01-01

    This paper address the phenomenon of drones and their potential relationship with the city from the point of view of the so-called “mobilities turn”. This is done in such a way that turns attention to a recent redevelopment of the “turn” towards design; so the emerging perspective of “mobilities...... design” will be used as a background perspective to reflect upon the future of drones in cities. The other perspective used to frame the phenomenon is the emerging discourse of the “smart city”. A city of proliferating digital information and data communication may be termed a smart city as shorthand...... on the block” that will potentially be a game-changer for urban governance, economics and everyday life. Here we are thinking of the unmanned aerial vehicle or drone as the popular term has it. Therefore, the paper asks how life in “drone city” may play out. Drones may alter the notion of surveillance by means...

  8. Sustainable Cities

    DEFF Research Database (Denmark)

    Georg, Susse; Garza de Linde, Gabriela Lucía

    /assessment tool. The context for our study is urban regeneration in one Danish city, which had been suffering from industrial decline and which is currently investing in establishing a “sustainable city”. Based on this case study we explore how the insights and inspiration evoked in working with the tool...

  9. Holomorphic Dynamics and Herman Rings

    DEFF Research Database (Denmark)

    Henriksen, Christian

    1997-01-01

    Existence theorem for Herman Rings of holomorphic mappings in a certain holomorphic family is given, using quasiconformal mappings. Proofs of topological properties of these Herman rings are given.......Existence theorem for Herman Rings of holomorphic mappings in a certain holomorphic family is given, using quasiconformal mappings. Proofs of topological properties of these Herman rings are given....

  10. Combining VLBI and ring laser observations at normal equation level

    Science.gov (United States)

    Schartner, Matthias; Böhm, Johannes; Böhm, Sigrid; Schreiber, Karl Ulrich; Gebauer, André

    2017-04-01

    Observations from ring laser gyroscopes can be used to continuously monitor earth rotation with high resolution and without an external reference frame, which makes them unique in contrast to other techniques like VLBI or GNSS. A combination, however, of ring laser and VLBI data could potentially result in an improved accuracy of estimated earth rotation parameters. In this study, we use observations from the ring laser "G" (Grossring) located at Wettzell (Germany) and combine them with VLBI observations at the normal equation level. The Vienna VLBI and Satellite Software (VieVS) is used to set up the normal equations for each VLBI session as SINEX files. We present combined estimates for polar motion and length of day and assess the impact by the ring laser observations.

  11. Thermodynamic black di-rings

    CERN Document Server

    Iguchi, Hideo

    2010-01-01

    Previously the five dimensional $S^1$-rotating black rings have been superposed in concentric way by some solitonic methods and regular systems of two $S^1$-rotating black rings were constructed by the authors and then Evslin and Krishnan (we called these solutions black di-rings). In this place we show some characteristics of the solutions of five dimensional black di-rings, especially in thermodynamic equilibrium. After the summary of the di-ring expressions and their physical quantities, first we comment on the equivalence of the two different solution-sets of the black di-rings. Then the existence of thermodynamic black di-rings are shown, in which both iso-thermality and iso-rotation between the inner black ring and the outer black ring are realized. We also give detailed analysis of peculiar properties of the thermodynamic black di-ring including discussion about a certain kind of thermodynamic stability (instability) of the system.

  12. Ringed accretion disks: equilibrium configurations

    CERN Document Server

    Pugliese, D

    2015-01-01

    We investigate a model of ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the General Relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can be then determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We pr...

  13. Reinventing the Solar Power Satellite

    Science.gov (United States)

    Landis, Geoffrey A.

    2004-01-01

    The selling price of electrical power varies with time. The economic viability of space solar power is maximum if the power can be sold at peak power rates, instead of baseline rate. Price and demand of electricity was examined from spot-market data from four example markets: New England, New York City, suburban New York, and California. The data was averaged to show the average price and demand for power as a function of time of day and time of year. Demand varies roughly by a factor of two between the early-morning minimum demand, and the afternoon maximum; both the amount of peak power, and the location of the peak, depends significantly on the location and the weather. The demand curves were compared to the availability curves for solar energy and for tracking and non-tracking satellite solar power systems in order to compare the market value of terrestrial and solar electrical power. In part 2, new designs for a space solar power (SSP) system were analyzed to provide electrical power to Earth for economically competitive rates. The approach was to look at innovative power architectures to more practical approaches to space solar power. A significant barrier is the initial investment required before the first power is returned. Three new concepts for solar power satellites were invented and analyzed: a solar power satellite in the Earth-Sun L2 point, a geosynchronous no-moving parts solar power satellite, and a nontracking geosynchronous solar power satellite with integral phased array. The integral-array satellite had several advantages, including an initial investment cost approximately eight times lower than the conventional design.

  14. Saturn's Other Ring Current

    Science.gov (United States)

    Crary, F. J.

    2014-04-01

    Saturn's main rings orbit the planet within an atmosphere and ionosphere of water, oxygen and hydrogen, produced by meteoritic impacts on and ultraviolet photodesorbtion of the ring particles [Johnson et al., 2006; Luhmann et al., 2006; Tseng et al., 2010]. The neutral atmosphere itself has only been tentatively detected through ultraviolet fluorescents of OH [Hall et al., 1996] while the ionosphere was observed in situ by the Cassini spacecraft shortly after orbital insertion [Coates et al.,2005; Tokar et al. 2005, Waite et al. 2005]. Although the plasma flow velocity of this ionosphere is not well-constrained, but the close association with the rings suggests that its speed would be couppled to the keplarian velocity of the rings themselves. As a result, the motion of the plasma through Saturn's magnetic field would produce an induced voltage, oriented away from the planet outside synchronous orbit and towards the planet inside synchronous orbit. Such a potential could result in currents flowing across the ring plane and closeing along magnetic field lines and through Saturn's ionosphere at latitudes between 36o and 48o. Cassini observations of whistler-mode plasma wave emissions [Xin et al.,2006] centered on synchronous orbit (1.76 Rs, mapping to 41o latitude) have been interpreted as a product of field-aligned electron beams associated with such a current. This presentation will investigate the magnitude of these currents and the resulting Joule heating of the ionosphere. An important constraint is that no auroral ultraviolet emissions have been observed at the relevant latitudes. In contrast, Joule heating could affect infrared emissions from H3+. Variations in H3+ emission associated with Saturn's rings have been reported by O'Donoghue et al., 2013, and interpreted as a result of ring "rain", i.e. precipitating water group species from the rings which alter ionosphereic chemistry and H3+ densities. As noted by O'Donoghue et al., this interpretation may be

  15. Spatial integration of oasis city group around the western margins of the Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper,the oasis cities in Kashgar Prefecture and Kizilsu Kirgiz Autonomous Prefecture are taken as an example,through the factor analysis,spatial attraction interaction model and location quotient methods,urban hierarchy system,the intensity of urban economic ties,economic subordination degree,and structure of city functions were analyzed. The results indicated:(1) The urban hierarchy system takes Kashgar city as the main center,Artux city,Yarkant county and Maralbexi county as the sub-centers; (2) The intensity of economic ties among Kashgar city and each county is much higher than others. The interaction of Kashgar city,Shufu county and Shule county are the strongest,and the economic ties of Yarkant,Kagilik,Poskam counties are relatively close; All cities in the study area are economically subordinate to Kashgar city. (3) Three cities of Kashgar city,Shufu county and Shule county should connect strongly,with Kashgar city as the core. The cities and towns along the Southern Xinjiang Railway and along National Road 315 should be regarded as two strips,and the two city strips along the border,and the city strip along Provincial Road 215 should be treated as three axes. The ring structure strategy of "core ring,closer ring and radiated ring" was proposed. (4) It was proposed to build Kashgar city group in the north,and Yarkant city group in the south,Maralbexi city group in the southeast,and Taxkorgan border city group with four inner groups’ development strategy.

  16. Geostationary Satellite (GOES) Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from radiometer instruments on SMS (ATS) and GOES satellites in geostationary orbit. These satellites produced...

  17. Appearance of Saturn's F ring azimuthal channels for the anti-alignment configuration between the ring and Prometheus

    CERN Document Server

    Chavez, Carlos E

    2009-01-01

    In this article we explore the aspect of the F ring with respect to the anti-alignment configuration between the ring and Prometheus. We focus our attention on the shape of the F ring's azimuthal channels which were first reported by Porco et al. (2005) and numerically explored by Murray et al. (2005), who found excellent agreement between Cassini's ISS reprojected images and their numerical model via a direct comparison. We find that for anti-alignment the channels are wider and go deeper inside the ring material. From our numerical model we find a new feature, an island in the middle of the channel. This island is made up of the particles that have been perturbed the most by Prometheus and only appears when this satellite is close to apoapsis. In addition, plots of the anti-alignment configuration for different orbital stages of Prometheus are obtained and discussed here.

  18. 徐州市三环南路沿线土壤重金属污染及相关性分析%Analysis on Pollution and Correlation of Heavy Metals in Soil along Third Ring South Road in Xuzhou City

    Institute of Scientific and Technical Information of China (English)

    刘伟; 刘汉湖; 邱超; 蔡香丽

    2012-01-01

    Taking the soil along third ring south road of Xuzhou city as research object, this paper researched on the soils pol- luted by heavy metals and correlations through sampling outside and indoor analysis. The results show that contents of the same heavy metal vary significantly in different sampling transects. In addition to types of heavy metals and sources, the availability of sheherbelts and density of shelterbelts are influencing factors. Zn, a major pollution factor, comes from the abrasion of motor vehi- cle tires. The result showed that heavy metals of Cu, Cr, Zn and Pb were not derived from natural sources, but closely related to human behaviors.%以徐州市三环南路沿线土壤为研究对象,经过野外调查取样和室内分析,对路旁土壤重金属污染及相关性进行了研究。结果表明:不同断面同一重金属含量之间存在显著性差异,这与重金属的种类、来源有关外,还与公路旁有无防护林及防护林的稠密度有关;土壤重金属污染最主要的贡献者是Zn,来自于机动车轮胎的磨损;根据土壤重金属元素之间及重金属与土壤理化性质之间的相关性分析可知,重金属Cu、Cr、Zn和Pb并不是来源于自然来源,而与人为来源有着紧密的关系。

  19. Oligomeric ferrocene rings

    Science.gov (United States)

    Inkpen, Michael S.; Scheerer, Stefan; Linseis, Michael; White, Andrew J. P.; Winter, Rainer F.; Albrecht, Tim; Long, Nicholas J.

    2016-09-01

    Cyclic oligomers comprising strongly interacting redox-active monomer units represent an unknown, yet highly desirable class of nanoscale materials. Here we describe the synthesis and properties of the first family of molecules belonging to this compound category—differently sized rings comprising only 1,1‧-disubstituted ferrocene units (cyclo[n], n = 5-7, 9). Due to the close proximity and connectivity of centres (covalent Cp-Cp linkages; Cp = cyclopentadienyl) solution voltammograms exhibit well-resolved, separated 1e- waves. Theoretical interrogations into correlations based on ring size and charge state are facilitated using values of the equilibrium potentials of these transitions, as well as their relative spacing. As the interaction free energies between the redox centres scale linearly with overall ring charge and in conjunction with fast intramolecular electron transfer (˜107 s-1), these molecules can be considered as uniformly charged nanorings (diameter ˜1-2 nm).

  20. Rings dominate western Gulf

    Science.gov (United States)

    Vidal L., Francisco V.; Vidal L., Victor M. V.; Molero, José María Pérez

    Surface and deep circulation of the central and western Gulf of Mexico is controlled by interactions of rings of water pinched from the gulf's Loop Current. The discovery was made by Mexican oceanographers who are preparing a full-color, 8-volume oceanographic atlas of the gulf.Anticyclonic warm-core rings pinch off the Loop Current at a rate of about one to two per year, the scientists of the Grupo de Estudios Oceanográficos of the Instituto de Investigaciones Eléctricas (GEO-IIE) found. The rings migrate west until they collide with the continental shelf break of the western gulf, almost always between 22° and 23°N latitude. On their westward travel they transfer angular momentum and vorticity to the surrounding water, generating cyclonic circulations and vortex pairs that completely dominate the entire surface and deep circulation of the central and western gulf.

  1. Autocatalytic chemical smoke rings

    CERN Document Server

    Rogers, M C; Rogers, Michael C.; Morris, Stephen W.

    2005-01-01

    Buoyant plumes, evolving free of boundary constraints, may develop well-defined mushroom shaped heads. In normal plumes, overturning flow in the head entrains less buoyant fluid from the surroundings as the head rises, robbing the plume of its driving force. We consider here a new type of plume in which the source of buoyancy is an autocatalytic chemical reaction. The reaction occurs at a sharp front which separates reactants from less dense products. In this type of plume, entrainment assists the reaction, producing new buoyancy which fuels an accelerating plume head. When the head has grown to a critical size, it detaches from the upwelling conduit, forming an accelerating, buoyant vortex ring. This vortex is analogous to a rising smoke ring. A second-generation head then develops at the point of detachment.Multiple generations of chemical vortex rings can detach from a single triggering event.

  2. Decay ring design

    CERN Document Server

    Chancé, A; Bouquerel, E; Hancock, S; Jensen, E

    The study of the neutrino oscillation between its different flavours needs pureand very intense fluxes of high energy, well collimated neutrinos with a welldetermined energy spectrum. A dedicated machine seems to be necessarynowadays to reach the required flux. A new concept based on the β-decayof radioactive ions which were accelerated in an accelerator chain was thenproposed. After ion production, stripping, bunching and acceleration, the unstableions are then stored in a racetrack-shaped superconducting decay ring.Finally, the ions are accumulated in the decay ring until being lost. The incomingbeam is merged to the stored beam by using a specific RF system, whichwill be presented here.We propose here to study some aspects of the decay ring, such as its opticalproperties, its RF system or the management of the losses which occur in thering (mainly by decay or by collimation).

  3. Almost ring theory

    CERN Document Server

    2003-01-01

    This book develops thorough and complete foundations for the method of almost etale extensions, which is at the basis of Faltings' approach to p-adic Hodge theory. The central notion is that of an "almost ring". Almost rings are the commutative unitary monoids in a tensor category obtained as a quotient V-Mod/S of the category V-Mod of modules over a fixed ring V; the subcategory S consists of all modules annihilated by a fixed ideal m of V, satisfying certain natural conditions. The reader is assumed to be familiar with general categorical notions, some basic commutative algebra and some advanced homological algebra (derived categories, simplicial methods). Apart from these general prerequisites, the text is as self-contained as possible. One novel feature of the book - compared with Faltings' earlier treatment - is the systematic exploitation of the cotangent complex, especially for the study of deformations of almost algebras.

  4. On Simple Noetherian Rings

    Institute of Scientific and Technical Information of China (English)

    Somyot Plubtieng

    2003-01-01

    A module M is called a CS-module (or extending module [5]) if every submodule of M is essential in a direct summand of M. It is shown that (i) a simple ring R is right noetherian if and only if every cyclic singular right R-module is either a CS-module or a noetherian module; (ii) for a prime ring R, if every proper cyclic right R-module is a direct sum of a quasi-injective module and a finitely cogenerated module, then R is either semisimple artinian or a right Ore domain; and (iii) a prime ring R is right noetherian if and only if every cyclic right R-module is a direct sum of a quasi-injective module and a noetherian module.

  5. Tunneling Through Black Rings

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liu

    2007-01-01

    Hawking radiation of black ring solutions to 5-dimensional Einstein-Maxwell-dilaton theory is analyzed by use of the Parikh-Wilczek tunneling method. To get the correct tunneling amplitude and emission rate, we adopt and develop the Angheben-Nadalini-Vanzo-Zerbini covariant approach to cover the effects of rotation and electronic discharge all at once, and the effect of back reaction is also taken into account. This constitutes a unified approach to the tunneling problem. Provided the first law of thermodynamics for black rings holds, the emission rate is proportional to the exponential of the change of Bekenstein-Hawking entropy. Explicit calculation for black ring temperatures agrees exactly with the results obtained via the classical surface gravity method and the quasi-local formalism.

  6. Deployable Fresnel Rings

    Science.gov (United States)

    Kennedy, Timothy F.; Fink, Patrick W.; Chu, Andrew W.; Lin, Gregory Y.

    2014-01-01

    Deployable Fresnel rings (DFRs) significantly enhance the realizable gain of an antenna. This innovation is intended to be used in combination with another antenna element, as the DFR itself acts as a focusing or microwave lens element for a primary antenna. This method is completely passive, and is also completely wireless in that it requires neither a cable, nor a connector from the antenna port of the primary antenna to the DFR. The technology improves upon the previous NASA technology called a Tri-Sector Deployable Array Antenna in at least three critical aspects. In contrast to the previous technology, this innovation requires no connector, cable, or other physical interface to the primary communication radio or sensor device. The achievable improvement in terms of antenna gain is significantly higher than has been achieved with the previous technology. Also, where previous embodiments of the Tri-Sector antenna have been constructed with combinations of conventional (e.g., printed circuit board) and conductive fabric materials, this innovation is realized using only conductive and non-conductive fabric (i.e., "e-textile") materials, with the possible exception of a spring-like deployment ring. Conceptually, a DFR operates by canceling the out-of-phase radiation at a plane by insertion of a conducting ring or rings of a specific size and distance from the source antenna, defined by Fresnel zones. Design of DFRs follow similar procedures to those outlined for conventional Fresnel zone rings. Gain enhancement using a single ring is verified experimentally and through computational simulation. The experimental test setup involves a microstrip patch antenna that is directly behind a single-ring DFR and is radiating towards a second microstrip patch antenna. The first patch antenna and DFR are shown. At 2.42 GHz, the DFR improves the transmit antenna gain by 8.6 dB, as shown in Figure 2, relative to the wireless link without the DFR. A figure illustrates the

  7. Sustainable Cities

    DEFF Research Database (Denmark)

    Georg, Susse; Garza de Linde, Gabriela Lucía

    Judging from the number of communities and cities striving or claiming to be sustainable and how often eco-development is invoked as the means for urban regeneration, it appears that sustainable and eco-development have become “the leading paradigm within urban development” (Whitehead 2003......), urban design competitions are understudied mechanisms for bringing about field level changes. Drawing on actor network theory, this paper examines how urban design competitions may bring about changes within the professional field through the use of intermediaries such as a sustainable planning....../assessment tool. The context for our study is urban regeneration in one Danish city, which had been suffering from industrial decline and which is currently investing in establishing a “sustainable city”. Based on this case study we explore how the insights and inspiration evoked in working with the tool...

  8. Sharing City

    DEFF Research Database (Denmark)

    This magazine offers an insight into the growing commercial innovation, civic movements, and political narratives surrounding sharing economy services, solutions and organisational types. It presents a cross-section of the manifold sharing economy services and solutions that can be found in Denmark....... Solutions of sharing that seeks to improve our cities and local communities in both urban and rural environments. 24 sharing economy organisations and businesses addressing urban and rural issues are being portrayed and seven Danish municipalities that have explored the potentials of sharing economy....... Moreover, 15 thought leading experts - professionals and academic - have been invited to give their perspective on sharing economy for cities. This magazine touches upon aspects of the sharing economy as mobility, communities, sustainability, business development, mobility, and urban-rural relation....

  9. Saturn's rings - high resolution

    Science.gov (United States)

    1981-01-01

    Voyager 2 obtained this high-resolution picture of Saturn's rings Aug. 22, when the spacecraft was 4 million kilometers (2.5 million miles) away. Evident here are the numerous 'spoke' features, in the B-ring; their very sharp, narrow appearance suggests short formation times. Scientists think electromagnetic forces are responsible in some way for these features, but no detailed theory has been worked out. Pictures such as this and analyses of Voyager 2's spoke movies may reveal more clues about the origins of these complex structures. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.

  10. On the mass and origin of Chariklo's rings

    CERN Document Server

    Pan, Margaret

    2016-01-01

    Observations in 2013 and 2014 of the Centaur 10199 Chariklo and its ring system consistently indicated that the radial width of the inner, more massive ring varies with longitude. That strongly suggests that this ring has a finite eccentricity despite the fast differential precession that Chariklo's large quadrupole moment should induce. If the inferred apse alignment is maintained by the ring's self-gravity, as it is for the Uranian rings, we estimate a ring mass of a few times 10^16 g and a typical particle size of a few meters. These imply a short collisional spreading time of ~10^5 years, somewhat shorter than the typical Centaur dynamical lifetime of a few Myrs and much shorter than the age of the solar system. In light of this time constraint, we evaluate previously suggested ring formation pathways including collisional ejection and satellite disruption. We also investigate in detail a contrasting formation mechanism, the lofting of dust particles off Chariklo's surface into orbit via outflows of subli...

  11. Space Weather Effects Produced by the Ring Current Particles

    Science.gov (United States)

    Ganushkina, Natalia; Jaynes, Allison; Liemohn, Michael

    2017-10-01

    One of the definitions of space weather describes it as the time-varying space environment that may be hazardous to technological systems in space and/or on the ground and/or endanger human health or life. The ring current has its contributions to space weather effects, both in terms of particles, ions and electrons, which constitute it, and magnetic and electric fields produced and modified by it at the ground and in space. We address the main aspects of the space weather effects from the ring current starting with brief review of ring current discovery and physical processes and the Dst-index and predictions of the ring current and storm occurrence based on it. Special attention is paid to the effects on satellites produced by the ring current electrons. The ring current is responsible for several processes in the other inner magnetosphere populations, such as the plasmasphere and radiation belts which is also described. Finally, we discuss the ring current influence on the ionosphere and the generation of geomagnetically induced currents (GIC).

  12. ON THE MASS AND ORIGIN OF CHARIKLO’S RINGS

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Margaret; Wu, Yanqin, E-mail: pan@astro.utoronto.ca [Department of Astronomy and Astrophysics, 50 St. George Street, University of Toronto (Canada)

    2016-04-10

    Observations in 2013 and 2014 of the Centaur 10199 Chariklo and its ring system consistently indicated that the radial width of the inner, more massive ring varies with longitude. That strongly suggests that this ring has a finite eccentricity despite the fast differential precession that Chariklo’s large quadrupole moment should induce. If the inferred apse alignment is maintained by the ring’s self-gravity, as it is for the Uranian rings, we estimate a ring mass of a few times 10{sup 16} g and a typical particle size of a few meters. These values imply a collisional spreading time of ∼10{sup 5} years, which is somewhat shorter than the typical Centaur dynamical lifetime of a few million years and much shorter than the age of the solar system. In light of this time constraint, we evaluate previously suggested ring formation pathways including collisional ejection and satellite disruption. We also investigate in detail a contrasting formation mechanism, the lofting of dust particles off Chariklo’s surface into orbit via outflows of sublimating CO and/or N{sub 2} triggered after Chariklo was scattered inward by giant planets. This alternate scenario predicts that rings should be common among 100 km class Centaurs but rare among Kuiper Belt objects and smaller Centaurs. It also predicts that Centaurs should show seasonal variations in cometary activity with activity maxima occurring shortly after equinox.

  13. AN N-BODY INTEGRATOR FOR GRAVITATING PLANETARY RINGS, AND THE OUTER EDGE OF SATURN'S B RING

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, Joseph M. [Space Science Institute, c/o Center for Space Research, University of Texas at Austin, 3925 West Braker Lane, Suite 200, Austin, TX 78759-5378 (United States); Spitale, Joseph N., E-mail: jhahn@spacescience.org, E-mail: jnspitale@psi.edu [Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719-2395 (United States)

    2013-08-01

    A new symplectic N-body integrator is introduced, one designed to calculate the global 360 Degree-Sign evolution of a self-gravitating planetary ring that is in orbit about an oblate planet. This freely available code is called epi{sub i}nt, and it is distinct from other such codes in its use of streamlines to calculate the effects of ring self-gravity. The great advantage of this approach is that the perturbing forces arise from smooth wires of ring matter rather than discreet particles, so there is very little gravitational scattering and so only a modest number of particles are needed to simulate, say, the scalloped edge of a resonantly confined ring or the propagation of spiral density waves. The code is applied to the outer edge of Saturn's B ring, and a comparison of Cassini measurements of the ring's forced response to simulations of Mimas's resonant perturbations reveals that the B ring's surface density at its outer edge is {sigma}{sub 0} = 195 {+-} 60 g cm{sup -2}, which, if the same everywhere across the ring, would mean that the B ring's mass is about 90% of Mimas's mass. Cassini observations show that the B ring-edge has several free normal modes, which are long-lived disturbances of the ring-edge that are not driven by any known satellite resonances. Although the mechanism that excites or sustains these normal modes is unknown, we can plant such a disturbance at a simulated ring's edge and find that these modes persist without any damping for more than {approx}10{sup 5} orbits or {approx}100 yr despite the simulated ring's viscosity {nu}{sub s} = 100 cm{sup 2} s{sup -1}. These simulations also indicate that impulsive disturbances at a ring can excite long-lived normal modes, which suggests that an impact in the recent past by perhaps a cloud of cometary debris might have excited these disturbances, which are quite common to many of Saturn's sharp-edged rings.

  14. Images of Neptune's ring arcs obtained by a ground-based telescope

    Science.gov (United States)

    Sicardy, B.; Roddier, F.; Roddier, C.; Perozzi, E.; Graves, J. E.; Guyon, O.; Northcott, M. J.

    1999-08-01

    Neptune has a collection of incomplete narrow rings, known as ring arcs, which should in isolation be destroyed by differential motion in a matter of months. Yet since first discovered by stellar occultations in 1984, they appear to have persisted, perhaps through a gravitational resonance effect involving the satellite Galatea. Here we report ground-based observations of the ring arcs, obtained using an adaptive optics system. Our data, and those obtained using the Hubble Space Telescope (reported in a companion paper), indicate that the ring arcs are near, but not within the resonance with Galatea, in contrast to what is predicted by some models.

  15. E ring dust sources: Implications from Cassini's dust measurements

    Science.gov (United States)

    Spahn, Frank; Albers, Nicole; Hörning, Marcel; Kempf, Sascha; Krivov, Alexander V.; Makuch, Martin; Schmidt, Jürgen; Seiß, Martin; Miodrag Sremčević

    2006-08-01

    The Enceladus flybys of the Cassini spacecraft are changing our understanding of the origin and sustainment of Saturn's E ring. Surprisingly, beyond the widely accepted dust production caused by micrometeoroid impacts onto the atmosphereless satellites (the impactor-ejecta process), geophysical activities have been detected at the south pole of Enceladus, providing an additional, efficient dust source. The dust detector data obtained during the flyby E11 are used to identify the amount of dust produced in the impactor-ejecta process and to improve related modeling [Spahn, F., Schmidt, J., Albers, N., Hörning, M., Makuch, M., Seiß, M., Kempf, S., Srama, R., Dikarev, V.V., Helfert, S., Moragas-Klostermeyer, G., Krivov, A.V., Sremčević, M., Tuzzolino, A., Economou, T., Grün, E., 2006. Cassini dust measurements at Enceladus: implications for Saturn's E ring. Science, in press]. With this, we estimate the impact-generated dust contributions of the other E ring satellites and find significant differences in the dust ejection efficiency by two projectile families - the E ring particles (ERPs) and the interplanetary dust particles (IDPs). Together with the Enceladus south-pole source, the ERP impacts play a crucial role in the inner region, whereas the IDP impacts dominate the particle production in the outer E ring, possibly accounting for its large radial extent. Our results can be verified in future Cassini flybys of the E ring satellites. In this way poorly known parameters of the dust particle production in hypervelocity impacts can be constrained by comparison of the data and theory.

  16. Design of a novel electrostatic ion storage ring at KACST

    CERN Document Server

    Ghazaly, M O A El; Welsch, C P; Alharbi, H H

    2013-01-01

    A new electrostatic storage ring for beams at energies up to 30keV.q is currently under development at the National Centre for Mathematics and Physics (NCMP), King Abdulaziz City for Science and Technology (KACST). The ring design is based on the existing electrostatic storage rings, but stretches significantly beyond them in that it shall form the core of a unique flexible experimental facility at KACST. The lattice of this ring has been designed in a way that enables the use of state-of-the-art experimental methods to study electron-ion, laser-ion, and ion-neutral beams interactions. The lattice design also allows for a future upgrade of the ring to a double storage ring structure that would enable ion-ion beam interactions to be performed. In this paper, we present the design of this ring with a focus on beam dynamics calculations for the 7o single-bend racetrack layout. The study is principally based on the SIMION8 program. We complemented this study further by using purpose-written routine and MAD-X simu...

  17. Ring chromosome 13

    DEFF Research Database (Denmark)

    Brandt, C A; Hertz, Jens Michael; Petersen, M B;

    1992-01-01

    A stillborn male child with anencephaly and multiple malformations was found to have the karyotype 46,XY,r(13) (p11q21.1). The breakpoint at 13q21.1, determined by high resolution banding, is the most proximal breakpoint ever reported in patients with ring chromosome 13. In situ hybridisation...

  18. Planetary ring systems

    CERN Document Server

    Miner, Ellis D; Cuzzi, Jeffrey N

    2007-01-01

    This is the most comprehensive and up-to-date book on the topic of planetary rings systems yet written. The book is written in a style that is easily accessible to the interested non expert. Each chapter includes notes, references, figures and tables.

  19. On topologies over rings

    Directory of Open Access Journals (Sweden)

    Syed M. Fakhruddin

    1985-01-01

    Full Text Available In this note, we show that if a topology F¯ over a ring A satisfies a certain finiteness condition, then the Gabriel topology G¯ generated by F¯ can be explicitly constructed and it also satisfies the same finiteness condition.

  20. The Saturn System's Icy Satellites: New Results from Cassini

    Science.gov (United States)

    Lopes-Gautier, Rosaly M.; Buratti, Bonnie; Hendrix, A. R.

    2008-01-01

    Cassini-Huygens is a multidisciplinary, international planetary mission consisting of an orbiting spacecraft and a probe. The Huygens probe successfully landed on Titan's surface on January 14, 2005, while the orbiter has performed observations of Saturn, its rings, satellites, and magnetosphere since it entered orbit around Saturn on July 1, 2004. The Cassini mission has been prolific in its scientific discoveries about the Saturn system. In this special section, we present new mission results with a focus on the 'icy satellites,' which we define as all Saturn's moons with the exception of Titan. The results included in this section have come out of the Cassini SOST--Satellites Orbiter Science Team--a multi-instrument and multidiscipline group that works together to better understand the icy satellites and their interactions with Saturn and its rings. Other papers included in this issue present ground-based observations and interior modeling of these icy moons.

  1. 3-dimensional current collection model. [of Tethered Satellite System 1

    Science.gov (United States)

    Hwang, Kai-Shen; Shiah, A.; Wu, S. T.; Stone, N.

    1992-01-01

    A three-dimensional, time dependent current collection model of a satellite has been developed for the TSS-1 system. The system has been simulated particularly for the Research of Plasma Electrodynamics (ROPE) experiment. The Maxwellian distributed particles with the geomagnetic field effects are applied in this numerical simulation. The preliminary results indicate that a ring current is observed surrounding the satellite in the equatorial plane. This ring current is found between the plasma sheath and the satellite surface and is oscillating with a time scale of approximately 1 microsec. This is equivalent to the electron plasma frequency. An hour glass shape of electron distribution was observed when the viewing direction is perpendicular to the equatorial plane. This result is consistent with previous findings from Linson (1969) and Antoniades et al. (1990). Electrons that are absorbed by the satellite are limited from the background ionosphere as indicated by Parker and Murphy (1967).

  2. Fusion Rings for Quantum Groups

    DEFF Research Database (Denmark)

    2012-01-01

    We study the fusion rings of tilting modules for a quantum group at a root of unity modulo the tensor ideal of negligible tilting modules. We identify them in type A with the combinatorial rings from [12] and give a similar description of the sp2n-fusion ring in terms of noncommutative symmetric...... functions. Moreover we give a presentation of all fusion rings in classical types as quotients of polynomial rings. Finally we also compute the fu- sion rings for type G2....

  3. Fusion Rings for Quantum Groups

    DEFF Research Database (Denmark)

    Andersen, Henning Haahr; Stroppel, Catharina

    2012-01-01

    We study the fusion rings of tilting modules for a quantum group at a root of unity modulo the tensor ideal of negligible tilting modules. We identify them in type A with the combinatorial rings from [12] and give a similar description of the sp2n-fusion ring in terms of noncommutative symmetric...... functions. Moreover we give a presentation of all fusion rings in classical types as quotients of polynomial rings. Finally we also compute the fu- sion rings for type G2....

  4. Rings Research in the Next Decade

    Science.gov (United States)

    Burns, J. A.; Tiscareno, M. S.

    2009-12-01

    The study of planetary ring systems forms a key component of planetary science for several reasons: 1) The evolution and current states of planets and their satellites are affected in many ways by rings, while 2) conversely, properties of planets and moons and other solar system populations are revealed by their effects on rings; 3) highly structured and apparently delicate ring systems may be bellwethers, constraining various theories of the origin and evolution of their entire planetary system; and finally, 4) planetary rings provide an easily observable analogue to other astrophysical disk systems, enabling real “ground truth” results applicable to disks much more remote in space and/or time, including proto-planetary disks, circum-stellar disks, and even galaxies. Significant advances have been made in rings science in the past decade. The highest-priority rings research recommendations of the last Planetary Science Decadal Survey were to operate and extend the Cassini orbiter mission at Saturn; this has been done with tremendous success, accounting for much of the progress made on key science questions, as we will describe. Important progress in understanding the rings of Saturn and other planets has also come from Earth-based observational and theoretical work, again as prioritized by the last Decadal Survey. However, much important work remains to be done. At Saturn, the Cassini Solstice Mission must be brought to a successful completion. Priority should also be placed on sending spacecraft to Neptune and/or Uranus, now unvisited for more than 20 years. At Jupiter and Pluto, opportunities afforded by visiting spacecraft capable of studying rings should be exploited. On Earth, the need for continued research and analysis remains strong, including in-depth analysis of rings data already obtained, numerical and theoretical modeling work, laboratory analysis of materials and processes analogous to those found in the outer solar system, and continued Earth

  5. A Sagittarius-Induced Origin for the Monoceros Ring

    CERN Document Server

    Michel-Dansac, Leo; Navarro, Julio F; Steinmetz, Matthias

    2011-01-01

    The Monoceros ring is a collection of stars in nearly-circular orbits at roughly 18 kpc from the Galactic center. It may have originated (i) as the response of the disc to perturbations excited by satellite companions or (ii) from the tidal debris of a disrupted dwarf galaxy. The metallicity of Monoceros stars differs from that of disc stars at comparable Galactocentric distances, an observation that disfavours the first scenario. On the other hand, circular orbits are difficult to accommodate in the tidal-disruption scenario, since it requires a satellite which at the time of disruption was itself in a nearly circular orbit. Such satellite could not have formed at the location of the ring and, given its low mass, dynamical friction is unlikely to have played a major role in its orbital evolution. We search cosmological simulations for low-mass satellites in nearly-circular orbits and find that they result, almost invariably, from orbital changes induced by collisions with more massive satellites: the radius ...

  6. Satellite economics in the 1980's

    Science.gov (United States)

    Morgan, W. L.

    1980-01-01

    Satellite traffic, competition, and decreasing costs are discussed, as are capabilities in telecommunication (including entertainment) and computation. Also considered are future teleconferencing and telecommuting to offset the cost of transportation, the establishment of a manufacturer-to-user link for increased home minicomputer capability, and an increase of digital over analog traffic. It is suggested that transcontinental bulk traffic, high-speed data, and multipoint private networks will eventually be handled by satellites which are cost-insensitive to distance, readily match dynamically varying multipoint networks, and have uniformly wide bandwidths available to both major cities and isolated towns.

  7. Ring autosomes: some unexpected findings.

    Science.gov (United States)

    Caba, L; Rusu, C; Plăiaşu; Gug, G; Grămescu, M; Bujoran, C; Ochiană, D; Voloşciuc, M; Popescu, R; Braha, E; Pânzaru, M; Butnariu, L; Sireteanu, A; Covic, M; Gorduza, Ev

    2012-12-01

    Ring chromosomes are rare entities, usually associated with phenotypic abnormalities in correlation with the loss of genetic material. There are various breakpoints and sometimes there is a dynamic mosaicism that is reflected in clinical features. Most of the ring chromosomes are de novo occurrences. Our study reflects the experience of three Romanian cytogenetic laboratories in the field of ring chromosomes. We present six cases with ring chromosomes involving chromosomes 5, 13, 18, and 21. All ring chromosomes were identified after birth in children with plurimalformative syndromes. The ring chromosome was present in mosaic form in three cases, and this feature reflects the ring's instability. In case of ring chromosome 5, we report a possible association with oculo-auriculo-vertebral spectrum.

  8. Assessment of different formation scenarios for the ring system of (10199) Chariklo

    Science.gov (United States)

    Melita, M. D.; Duffard, R.; Ortiz, J. L.; Campo-Bagatin, A.

    2017-06-01

    Context. The discovery that the Centaur (10199) Chariklo possesses a ring system opens questions about their origin. Aims: We here asses the plausibility of different scenarios for the origin of the observed ring system. Methods: We first consider the possibility that the material of the ring originated in the disruption of a satellite that had reached a critical distance from the Centaur. We discuss the conditions for the putative satellite to approach the Centaur as a consequence of tidal interaction. A three-body encounter is also considered as a transport mechanism. In addition, we study the case in which the ring is formed by the ejecta of a cratering collision on the Centaur and we constrain the collision parameters and the size of the resulting crater of the event. Finally, we consider that the ring material originates from a catastrophic collision between a background object and a satellite located at a distance corresponding to the the current location of the ring. We compute the typical timescales for these scenarios. Results: We estimate that in order to be tidally disrupted a satellite would have had to be larger than approximately 6.5 km at the location of the rings. However the tidal interaction is rather weak for objects of the size of outer solar system bodies at the ring location, therefore we considered other more effective mechanisms by which a satellite might have approached the Centaur. Collisonal scenarios are both physically plausible for the formation, but semianalytical estimations indicate that the probability of the corresponding collisions is low under current conditions.

  9. Satellite data compression

    CERN Document Server

    Huang, Bormin

    2011-01-01

    Satellite Data Compression covers recent progress in compression techniques for multispectral, hyperspectral and ultra spectral data. A survey of recent advances in the fields of satellite communications, remote sensing and geographical information systems is included. Satellite Data Compression, contributed by leaders in this field, is the first book available on satellite data compression. It covers onboard compression methodology and hardware developments in several space agencies. Case studies are presented on recent advances in satellite data compression techniques via various prediction-

  10. Trends in communications satellites

    CERN Document Server

    Curtin, Denis J

    1979-01-01

    Trends in Communications Satellites offers a comprehensive look at trends and advances in satellite communications, including experimental ones such as NASA satellites and those jointly developed by France and Germany. The economic aspects of communications satellites are also examined. This book consists of 16 chapters and begins with a discussion on the fundamentals of electrical communications and their application to space communications, including spacecraft, earth stations, and orbit and wavelength utilization. The next section demonstrates how successful commercial satellite communicati

  11. On Skew Triangular Matrix Rings

    Institute of Scientific and Technical Information of China (English)

    Wang Wei-liang; Wang Yao; Ren Yan-li

    2016-01-01

    Letαbe a nonzero endomorphism of a ring R, n be a positive integer and Tn(R,α) be the skew triangular matrix ring. We show that some properties related to nilpotent elements of R are inherited by Tn(R,α). Meanwhile, we determine the strongly prime radical, generalized prime radical and Behrens radical of the ring R[x;α]/(xn), where R[x;α] is the skew polynomial ring.

  12. e-læring

    DEFF Research Database (Denmark)

    Helms, Niels Henrik

    e-læring kan defineres på ganske mange måder. Ordet e-læring består jo tydeligt nok af to elementer. E + læring ligesom e-handel eller e-banking, og umiddelbart vil de fleste nok sige, at det så handler om læring vha. internettet. I bidraget advokeres for en læringsmæssig frem for normativ tilgang....

  13. The Black Ring is Unstable

    CERN Document Server

    Santos, Jorge E

    2015-01-01

    We study non-axisymmetric linearised gravitational perturbations of the Emparan-Reall black ring using numerical methods. We find an unstable mode whose onset lies within the "fat" branch of the black ring and continues into the "thin" branch. Together with previous results using Penrose inequalities that fat black rings are unstable, this provides numerical evidence that the entire black ring family is unstable.

  14. A Database of Invariant Rings

    OpenAIRE

    Kemper, Gregor; Körding, Elmar; Malle, Gunter; Matzat, B. Heinrich; Vogel, Denis; Wiese, Gabor

    2001-01-01

    We announce the creation of a database of invariant rings. This database contains a large number of invariant rings of finite groups, mostly in the modular case. It gives information on generators and structural properties of the invariant rings. The main purpose is to provide a tool for researchers in invariant theory.

  15. Integrated silicon optofluidic ring resonator

    NARCIS (Netherlands)

    Testa, G.; Huang, Y.; Sarro, P.M.; Zeni, L.; Bernini, R.

    2010-01-01

    The feasibility of an integrated silicon optofluidic ring resonator is demonstrated. Liquid core antiresonant reflecting optical waveguides are used to realize a rectangular ring resonator with a multimode interference liquid core coupler between the ring and the bus waveguide. In this configuration

  16. Non-Commutative Ring Theory

    CERN Document Server

    López-Permouth, Sergio

    1990-01-01

    The papers of this volume share as a common goal the structure and classi- fication of noncommutative rings and their modules, and deal with topics of current research including: localization, serial rings, perfect endomorphism rings, quantum groups, Morita contexts, generalizations of injectivitiy, and Cartan matrices.

  17. Ring closure in actin polymers

    Science.gov (United States)

    Sinha, Supurna; Chattopadhyay, Sebanti

    2017-03-01

    We present an analysis for the ring closure probability of semiflexible polymers within the pure bend Worm Like Chain (WLC) model. The ring closure probability predicted from our analysis can be tested against fluorescent actin cyclization experiments. We also discuss the effect of ring closure on bend angle fluctuations in actin polymers.

  18. RINGED ACCRETION DISKS: EQUILIBRIUM CONFIGURATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)

    2015-12-15

    We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

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

    Science.gov (United States)

    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. Branding Cities, Changing Societies

    DEFF Research Database (Denmark)

    Ooi, Can-Seng

    Societal changes are seldom discussed in the literature on city branding. The time element is important because it highlights the fluctuating reality of society. The city brand message freezes the place but in fact, the city branding exercise is a continuous process. Society emerges too. City...... brands are supposed to accentuate the uniqueness of the city, be built from the bottom-up and reflect the city's identity. This paper highlights three paradoxes, pointing out that city branding processes can also make cities more alike, bring about societal changes and forge new city identities. A city...... branding campaign does not just present the city, it may change the city. The relationships between the branding exercise and the city are intertwined in the evolution of the place....

  1. Saturn's ``Gossamer'' Ring: The F Ring's Inner Sheet

    Science.gov (United States)

    Showalter, M. R.; Burns, J. A.; Hamilton, D. P.

    1998-09-01

    Recent Galileo and Earth-based images have revealed for the first time that Jupiter's ``gossamer'' ring is actually composed of two rings, one bounded at the outer edge by Amalthea and the other bounded by Thebe. Dynamical models suggest that these rings are composed of dust grains ejected off the surfaces of the two moons, which then evolve inward under Poynting-Robertson drag. A very faint sheet of material filling the region between Saturn's A and F Rings reported by Burns et al. (BAAS 15, 1013--1014, 1983) may be a dynamically analogous system, in which dust escapes from the F Ring and evolves inward to the A Ring. Unlike Jupiter's gossamer rings, however, the inner sheet of Saturn's F Ring has been well observed from a large range of phase angles and visual wavelengths by Voyager. Voyager images reveal that this faint ring shows a tenfold increase in brightness between phase angles of 125(deg) and 165(deg) , indicating that it is composed of fine dust microns in size. Preliminary estimates of the normal optical depth fall in the range 1--2*E(-4) , depending on the dust size distribution assumed. Initial spectrophotometry reveals that the ring is neutral in color. The ring is uniform in brightness over the entire region between the two rings, with no evidence for internal structure associated with Prometheus and Atlas, suggesting that neither of these embedded moons acts as either a source or a sink. We will refine the aforementioned measurements and develop photometric models to better constrain the properties of the dust in this ring. This will enable us to relate the dust population to that in the F Ring proper, and to better explore the dynamical processes at work.

  2. The Linkage Between the Ionospheric Trough and Ring Current

    Science.gov (United States)

    Brandt, P. C.; Zheng, Y.; Talaat, E.; Sotirelis, T.; Foster, J. C.; Erickson, P. J.

    2007-05-01

    We present data-model investigations of how the ring current couples to the sub-auroral ionosphere. The ring current pressure distribution during storm and substorms is highly asymetrical and sets up the region 2 current system that closes through the sub-auroral ionosphere. Of particular interest is what happens in the so-called ionospheric trough region, which is a region in the evening ionosphere with extremely low conductance (few tenths of a mho). Observations show strong westward flows in the ionospheric trough (Sub-Auroral Polarization Stream - SAPS) and sometimes highly structured and variable. The Comprehensive Ring Current Model models the ring current by using the bounce averaged Boltzmann equation and allowing the ring current to close through the ionosphere. Our model ionosphere includes dayside and auroral conductance as well as semi-empirical representation of the trough conductance. By using realistic representations of the conductances we seek to explore how the ring current pressure distribution (and therefore the region 2 current system) is linked to the presence of the trough. We use data from the IMAGE satellite, the Millstone Hill and SuperDARN radar facilities.

  3. A ring system detected around the Centaur (10199) Chariklo

    CERN Document Server

    Braga-Ribas, F; Ortiz, J L; Snodgrass, C; Roques, F; Vieira-Martins, R; Camargo, J I B; Assafin, M; Duffard, R; Jehin, E; Pollock, J; Leiva, R; Emilio, M; Machado, D I; Colazo, C; Lellouch, E; Skottfelt, J; Gillon, M; Ligier, N; Maquet, L; Benedetti-Rossi, G; Gomes, A Ramos; Kervella, P; Monteiro, H; Sfair, R; Moutamid, M El; Tancredi, G; Spagnotto, J; Maury, A; Morales, N; Gil-Hutton, R; Roland, S; Ceretta, A; Gu, S -h; Wang, X -b; Harpsøe, K; Rabus, M; Manfroid, J; Opitom, C; Vanzi, L; Mehret, L; Lorenzini, L; Schneiter, E M; Melia, R; Lecacheux, J; Colas, F; Vachier, F; Widemann, T; Almenares, L; Sandness, R G; Char, F; Perez, V; Lemos, P; Martinez, N; Jørgensen, U G; Dominik, M; Roig, F; Reichart, D E; LaCluyze, A P; Haislip, J B; Ivarsen, K M; Moore, J P; Frank, N R; Lambas, D G

    2014-01-01

    Until now, rings have been detected in the Solar System exclusively around the four giant planets. Here we report the discovery of the first minor-body ring system around the Centaur object (10199) Chariklo, a body with equivalent radius 124$\\pm$9 km. A multi-chord stellar occultation revealed the presence of two dense rings around Chariklo, with widths of about 7 km and 3 km, optical depths 0.4 and 0.06, and orbital radii 391 and 405 km, respectively. The present orientation of the ring is consistent with an edge-on geometry in 2008, thus providing a simple explanation for the dimming of Chariklo's system between 1997 and 2008, and for the gradual disappearance of ice and other absorption features in its spectrum over the same period. This implies that the rings are partially composed of water ice. These rings may be the remnants of a debris disk, which were possibly confined by embedded kilometre-sized satellites.

  4. Pioneer fly-by of Saturn and its rings

    Science.gov (United States)

    Gehrels, T.; Esposito, L.

    1981-01-01

    Results acquired by the imaging photopolarimeter on board Pioneer 11 during the spacecraft fly-by of Saturn and its rings on September 1, 1979 are reviewed. Analysis of the broadband photometry and polarimetry obtained of the Saturn atmosphere has been used to determine a cloud top height of 300 mb and a scale height of the aerosol distribution about 1/4 that of the ambient gas, and to point out differences between the forward scattering and belt and zone characteristics of the Saturn and Jupiter atmospheres. Images of Saturn's rings have been used to derive a profile of ring optical depth between 1.22 and 2.35 Saturn radii, and reveal new divisions and thin rings and azimuthal variations in the brightness of the A ring not observable from earth. Linear polarization observations of Titan in red and blue light reveal that the aerosols near the top of the atmosphere have radii less than about 0.09 micron and that the optical thickness of the small aerosol layer is about 0.6 above an effectively depolarizing surface, and indicate radii of 2845 + or - 25 km and 2880 + or - 22 km in red and blue light, respectively. Earth-based and spacecraft data are consistent with the formation of rings structures as a result of Poynting-Robertson drag and gravitational satellite resonances with the original ice and rock particles.

  5. Computational studies of carbodiimide rings.

    Science.gov (United States)

    Damrauer, Robert; Lin, Hai; Damrauer, Niels H

    2014-05-02

    Computational studies of alicyclic carbodiimides (RN═C═NR) (rings five through twelve) at the MP2/6-31G(d,p)//MP2/6-31G(d,p) level of theory were conducted to locate the transition states between carbodiimides isomers. Transition states for rings six through twelve were found. The RNCNR dihedral angle is ∼0° for even-numbered rings, but deviates from 0° for rings seven, nine, eleven, and twelve. The even- and odd-numbered ring transition states have different symmetry point groups. Cs transition states (even rings) have an imaginary frequency mode that transforms as the asymmetric irreducible representation of the group. C2 transition states (odd rings) have a corresponding mode that transforms as the totally symmetric representation. Intrinsic reaction coordinate analyses followed by energy minimization along the antisymmetric pathways led to enantiomeric pairs. The symmetric pathways give diastereomeric isomers. The five-membered ring carbodiimide is a stable structure, possibly isolable. A twelve-membered ring transition state was found only without applying symmetry constraints (C1). Molecular mechanics and molecular dynamics studies of the seven-, eight-, and nine-membered rings gave additional structures, which were then minimized using ab initio methods. No structures beyond those found from the IRC analyses described were found. The potential for optical resolution of the seven-membered ring is discussed.

  6. Cellular Satellites: Joint Communications With Integrated Acquisition

    Science.gov (United States)

    2015-04-01

    PEO C3T). He has an master’s degree in Business Management from Oklahoma City University, a master’s in National Resource Strategy from the...battlespace.This progress is possible due to the Mobile User Objective System (MUOS), the next-generation narrowband military satellite communication system that...nodes in extreme latitudes. Other demonstrations continue, including assessments of communications perfor- mance with different applications and

  7. The KACST Heavy-Ion Electrostatic Storage Ring

    Science.gov (United States)

    Almuqhim, A. A.; Alshammari, S. M.; El Ghazaly, M. O. A.; Papash, A. I.; Welsch, C. P.

    2011-10-01

    A novel Electrostatic Storage Ring (ESR) for beams at energies up to 30keV/q is now being constructed at the National Centre for Mathematics and Physics (NCMP), King Abdul-Aziz City for Science and Technology (KACST). The ring is designed to be the core of a highly flexible experimental platform that will combine a large package of complementary beam techniques for atomic and molecular physics and related fields. The lattice design had to cover the different experimental techniques that the ring will be equipped with, such as e.g. Electron-Ion, Laser-Ion, Ion-Ion or Ion-Neutral beams, in both crossed and merged-beam configurations. The development of such an ESR is realized in a staged approach, in which a simple and early-run adaptation of the ring is built first, and then this basic version is upgraded to a higher symmetry of the ultimate version of the ring. Here, we report a general overview of this technical development with a focus on the layout of the first built stage of the ring.

  8. Magnetic fields in ring galaxies

    CERN Document Server

    Moss, D; Silchenko, O; Sokoloff, D; Horellou, C; Beck, R

    2016-01-01

    Many galaxies contain magnetic fields supported by galactic dynamo action. However, nothing definitive is known about magnetic fields in ring galaxies. Here we investigate large-scale magnetic fields in a previously unexplored context, namely ring galaxies, and concentrate our efforts on the structures that appear most promising for galactic dynamo action, i.e. outer star-forming rings in visually unbarred galaxies. We use tested methods for modelling $\\alpha-\\Omega$ galactic dynamos, taking into account the available observational information concerning ionized interstellar matter in ring galaxies. Our main result is that dynamo drivers in ring galaxies are strong enough to excite large-scale magnetic fields in the ring galaxies studied. The variety of dynamo driven magnetic configurations in ring galaxies obtained in our modelling is much richer than that found in classical spiral galaxies. In particular, various long-lived transients are possible. An especially interesting case is that of NGC 4513 where th...

  9. A season in Saturn's rings: Cycling, recycling and ring history

    Science.gov (United States)

    Esposito, L. W.; Meinke, B. K.; Albers, N.; Sremcevic, M.

    2012-04-01

    Cassini experiments have watched Saturn's ring system evolve before our eyes. Images and occultations show changes and transient events. The rings are a dynamic and complex geophysical system, incompletely modeled as a single-phase fluid. Key Cassini observations: High resolution images show straw, propellers, embedded moonlets, and F ring objects. Multiple UVIS, RSS and VIMS occutlations indicate multimodal ringlet and edge structure, including free and forced modes along with stochastic perturbations that are most likely caused by nearby mass concentrations. Vertical excursions are evident at ring edges and in other perturbed regions. The rings are occasionally hit by meteorites that leave a signature that may last centuries; meteoritic dust pollutes the rings. Temperature, reflectance and transmission spectra are influenced by the dynamical state of the ring particles. Saturn's Equinox 2009: Oblique lighting exposed vertical structure and embedded objects. The rings were the coldest ever. Images inspired new occultation and spectral analysis that show abundant structure in the perturbed regions. The rings are more variable and complex than we had expected prior to this seasonal viewing geometry. Sub-kilometer structure in power spectral analysis: Wavelet analysis shows features in the strongest density waves and at the shepherded outer edge of the B ring. Edges are variable as shown by multiple occultations and occultations of double stars. F ring kittens: 25 features seen in the first 102 occultations show a weak correlation with Prometheus location. We interpret these features as temporary aggregations. Simulation results indicate that accretion must be enhanced to match the kittens' size distribution. Images show that Prometheus triggers the formation of transient objects. Propellers and ghosts: Occulations and images provide evidence for small moonlets in the A, B and C rings. These indicate accretion occurs inside the classical Roche limit. Implications

  10. Retrospective on 20 Years of Friendship-City Ties Between Yangzhou and Kent, Washington State

    Institute of Scientific and Technical Information of China (English)

    Yang; Le

    2014-01-01

    <正>This year marks the 20th anniversary of the establishment of friendship-city relations between Kent,a satellite city of Seattle with a population of 92,000 and covering an area of 34.19 square miles,and Yangzhou.Kent was the third foreign city to make such arrangement with the central-eastern Chinese city.Friendship and Exchanges of Gifts Yangzhou started

  11. Expats rank Chinese cities

    Institute of Scientific and Technical Information of China (English)

    By Lv Dong

    2012-01-01

    Beijing, April The results of the "2011 Amazing China- The Most Attractive Chinese Cities for Foreigners" election are released. Expats choose Beijing, Shanghai, Tianjin and other cities as Chinas 10 most attractive cities for foreigners.

  12. Pittsburgh City Facilities

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Pittsburgh City FacilitiesIncludes: City Administrative Buildings, Police Stations, Fire Stations, EMS Stations, DPW Sites, Senior Centers, Recreation Centers, Pool...

  13. Pittsburgh City Facilities

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Pittsburgh City FacilitiesIncludes: City Administrative Buildings, Police Stations, Fire Stations, EMS Stations, DPW Sites, Senior Centers, Recreation Centers,...

  14. Xichang Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    Xichang Satellite Launch Center(XSLC) is mainly for geosynchronous orbit launches. The main purpose of XSLC is to launch spacecraft, such as broadcasting,communications and meteorological satellites, into geo-stationary orbit.Most of the commercial satellite launches of Long March vehicles have been from Xichang Satellite Launch Center. With 20 years' development,XSLC can launch 5 kinds of launch vehicles and send satellites into geostationary orbit and polar orbit. In the future, moon exploration satellites will also be launched from XSLC.

  15. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2017-01-01

    The first edition of this ground breaking reference work was the most comprehensive reference source available about the key aspects of the satellite applications field. This updated second edition covers the technology, the markets, applications and regulations related to satellite telecommunications, broadcasting and networking—including civilian and military systems; precise satellite navigation and timing networks (i.e. GPS and others); remote sensing and meteorological satellite systems. Created under the auspices of the International Space University based in France, this brand new edition is now expanded to cover new innovative small satellite constellations, new commercial launching systems, innovation in military application satellites and their acquisition, updated appendices, a useful glossary and more.

  16. Cities, Towns and Villages - City Limit (polygon)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Data available online through GeoStor at http://www.geostor.arkansas.gov. Arkansas Cities: This data set contains all of the city limit boundaries within the state...

  17. Galileo satellite antenna modeling

    Science.gov (United States)

    Steigenberger, Peter; Dach, Rolf; Prange, Lars; Montenbruck, Oliver

    2015-04-01

    The space segment of the European satellite navigation system Galileo currently consists of six satellites. Four of them belong to the first generation of In-Orbit Validation (IOV) satellites whereas the other two are Full Operational Capability (FOC) satellites. High-precision geodetic applications require detailed knowledge about the actual phase center of the satellite and receiver antenna. The deviation of this actual phase center from a well-defined reference point is described by phase center offsets (PCOs) and phase center variations (PCVs). Unfortunately, no public information is available about the Galileo satellite antenna PCOs and PCVs, neither for the IOV, nor the FOC satellites. Therefore, conventional values for the IOV satellite antenna PCOs have been adopted for the Multi-GNSS experiment (MGEX) of the International GNSS Service (IGS). The effect of the PCVs is currently neglected and no PCOs for the FOC satellites are available yet. To overcome this deficiency in GNSS observation modeling, satellite antenna PCOs and PCVs are estimated for the Galileo IOV satellites based on global GNSS tracking data of the MGEX network and additional stations of the legacy IGS network. Two completely independent solutions are computed with the Bernese and Napeos software packages. The PCO and PCV values of the individual satellites are analyzed and the availability of two different solutions allows for an accuracy assessment. The FOC satellites are built by a different manufacturer and are also equipped with another type of antenna panel compared to the IOV satellites. Signal transmission of the first FOC satellite has started in December 2014 and activation of the second satellite is expected for early 2015. Based on the available observations PCO estimates and, optionally PCVs of the FOC satellites will be presented as well. Finally, the impact of the new antenna model on the precision and accuracy of the Galileo orbit determination is analyzed.

  18. Keeping the Edges Sharp II: Honing Simulations of Narrow Rings

    Science.gov (United States)

    Rimlinger, Thomas; Hamilton, Douglas; Hahn, Joseph M.

    2016-05-01

    It has long been believed that shepherd satellites are necessary to keep narrow rings confined. While a pair of nearby satellites brackets Saturn’s F ring and Uranus’ Epsilon ring, dozens of other ringlets observed around the outer three planets seem to be unattended. Hamilton et al. (this meeting) have argued analytically that eccentric or inclined rings can maintain their sharp edges for millions or even billions of years despite continually dissipating energy. Here, we present numerical integrations showing isolated eccentric ringlets that do not spread; our model includes only the gravity from an oblate planet, ring self-gravity, and viscosity. We use the symplectic integrator epi_int written by Hahn & Spitale (2013).For narrow rings, the weak perturbation forces that we study act on secular rather than orbital timescales. Therefore, we find that we can use an unusually long timestep, in which these weak forces are applied once every ~30 orbits, with good energy and angular momentum conservation. Long timesteps allow us to run simulations that might otherwise take hours or even days in a matter of minutes. We present comparisons between simulations with identical initial conditions but varying timesteps to show that our approach is appropriate for this class of problems. This technique of speeding up numerical integrations works for any symplectic integrator, requiring only that the forces be weak and that the timescale of interest be long. Problems well suited to this approach (those with only secular and drag forces) include tidally-damped exoplanets and dust grains subject to radiation pressure and Poynting-Robertson drag.

  19. Tree Rings: Timekeepers of the Past.

    Science.gov (United States)

    Phipps, R. L.; McGowan, J.

    One of a series of general interest publications on science issues, this booklet describes the uses of tree rings in historical and biological recordkeeping. Separate sections cover the following topics: dating of tree rings, dating with tree rings, tree ring formation, tree ring identification, sample collections, tree ring cross dating, tree…

  20. The Rings Characterized by Minimal Left Ideals

    Institute of Scientific and Technical Information of China (English)

    Jun Chao WEI

    2005-01-01

    We study these rings with every minimal left ideal being a projective, direct summand and a p-injective module, respectively. Some characterizations of these rings are given, and the relations among them are obtained. With these rings, we characterize semisimple rings. Finally, we introduce MC2 rings, and give some characterizations of MC2 rings.

  1. City positioning theories and city core competencies

    Institute of Scientific and Technical Information of China (English)

    Xinquan; Zhu

    2007-01-01

    Gity positioning The Chinese city in a decision develops the topic of the destiny. Since the 90's of 20 centuries, the economic integral and globalization developed rapidly. The development make national boundary become not so important, the function of the city is increasingly outstanding. In other words, national competition ability is morally now on the city competition ability. At the same time, this development result that the industry is divided internationally and is divided in cities. Therefore, under the condition of globalization, if the city wants the superior development, it must take advantages and avoid shortage, to position the city accurately, establish the competition and development the strategy. The city positioning is clearly defined the city competition ability, more important it indicated the direction of the city development. Trough the analysis of the resource and environment of the city, decide an accurate position of the best function of the city, well configure the inner and outside resource, catch the opportunities,face the challenges, maximized the market share in order to maximized the wealth and city competition ability.

  2. RING E3 ligases

    DEFF Research Database (Denmark)

    Cho, Seok Keun; Ryu, Moon Young; Kim, Jong Hum

    2017-01-01

    response pathways of plants through various molecular and genetic studies. In particular, it was recently discovered that ubiquitin proteasome system (UPS), a regulatory mechanism for protein turn over, is greatly involved in the stress responsive pathways. In the UPS, many E3 ligases play key roles...... in recognizing and tethering poly-ubiquitins on target proteins for subsequent degradation by the 26S proteasome. Here we discuss the roles of RING ligases that have been defined in related to abiotic stress responses in plants....

  3. Fusion Rings for Quantum Groups

    DEFF Research Database (Denmark)

    2014-01-01

    We study the fusion rings of tilting modules for a quantum group at a root of unity modulo the tensor ideal of negligible tilting modules. We identify them in type A with the combinatorial rings from Korff, C., Stroppel, C.: The sl(ˆn)k-WZNW fusion ring: a combinato-rial construction and a realis......We study the fusion rings of tilting modules for a quantum group at a root of unity modulo the tensor ideal of negligible tilting modules. We identify them in type A with the combinatorial rings from Korff, C., Stroppel, C.: The sl(ˆn)k-WZNW fusion ring: a combinato-rial construction...... and a realisation as quotient of quantum cohomology. Adv. Math. 225(1), 200–268, (2010) and give a similar description of the sp2n-fusion ring in terms of non-commutative symmetric functions. Moreover we give a presentation of all fusion rings in classical types as quotients of polynomial rings. Finally we also...... compute the fusion rings for type G2....

  4. Viscosity of ring polymer melts

    KAUST Repository

    Pasquino, Rossana

    2013-10-15

    We have measured the linear rheology of critically purified ring polyisoprenes, polystyrenes, and polyethyleneoxides of different molar masses. The ratio of the zero-shear viscosities of linear polymer melts η0,linear to their ring counterparts η0,ring at isofrictional conditions is discussed as a function of the number of entanglements Z. In the unentangled regime η0,linear/η 0,ring is virtually constant, consistent with the earlier data, atomistic simulations, and the theoretical expectation η0,linear/ η0,ring = 2. In the entanglement regime, the Z-dependence of ring viscosity is much weaker than that of linear polymers, in qualitative agreement with predictions from scaling theory and simulations. The power-law extracted from the available experimental data in the rather limited range 1 < Z < 20, η0,linear/η0,ring ∼ Z 1.2±0.3, is weaker than the scaling prediction (η0,linear/η0,ring ∼ Z 1.6±0.3) and the simulations (η0,linear/ η0,ring ∼ Z2.0±0.3). Nevertheless, the present collection of state-of-the-art experimental data unambiguously demonstrates that rings exhibit a universal trend clearly departing from that of their linear counterparts, and hence it represents a major step toward resolving a 30-year-old problem. © 2013 American Chemical Society.

  5. Satellite-Delivered Learning.

    Science.gov (United States)

    Arnall, Gail C.

    1987-01-01

    Discusses the application of satellite information delivery to training. Describes a new trend, horizontal programming. Also discusses vertical programming and in-house production of training materials. Lists vendors of satellite-based training. (CH)

  6. GPS Satellite Simulation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The GPS satellite simulation facility consists of a GPS satellite simulator controlled by either a Silicon Graphics Origin 2000 or PC depending upon unit under test...

  7. China's Recoverable Satellites

    Institute of Scientific and Technical Information of China (English)

    Tang Boehang

    2008-01-01

    @@ By the end of 2006, China had launched 24 recoverable satellites (FSW) in total. Among them, 23 were launched successfully, of which all but one were successfully recovered. Recoverable satellites launched by China are listed in Table 1.

  8. Satellite Tags- Hawaii EEZ

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Satellite tagging was implemented in 2013. Satellite tagging is conducted using a Dan Inject air rifle and deployment arrows designed by Wildlife Computers. Two...

  9. Satellite communication engineering

    CERN Document Server

    Kolawole, Michael Olorunfunmi

    2013-01-01

    An undeniably rich and thorough guide to satellite communication engineering, Satellite Communication Engineering, Second Edition presents the fundamentals of information communications systems in a simple and succinct way. This book considers both the engineering aspects of satellite systems as well as the practical issues in the broad field of information transmission. Implementing concepts developed on an intuitive, physical basis and utilizing a combination of applications and performance curves, this book starts off with a progressive foundation in satellite technology, and then moves on

  10. Buoyant Norbury's vortex rings

    Science.gov (United States)

    Blyth, Mark; Rodriguez-Rodriguez, Javier; Salman, Hayder

    2014-11-01

    Norbury's vortices are a one-parameter family of axisymmetric vortex rings that are exact solutions to the Euler equations. Due to their relative simplicity, they are extensively used to model the behavior of real vortex rings found in experiments and in Nature. In this work, we extend the original formulation of the problem to include buoyancy effects for the case where the fluid that lies within the vortex has a different density to that of the ambient. In this modified formulation, buoyancy effects enter the problem through the baroclinic term of the vorticity equation. This permits an efficient numerical solution of the governing equation of motion in terms of a vortex contour method that tracks the evolution of the boundary of the vortex. Finally, we compare our numerical results with the theoretical analysis of the short-time evolution of a buoyant vortex. Funded by the Spanish Ministry of Economy and Competitiveness through grant DPI2011-28356-C03-02 and by the London Mathematical Society.

  11. Taiyuan Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    There are three major space launch bases in China, the Jiuquan Satellite Launch Center,the Taiyuan Satellite Launch Center and the Xichang Satellite Launch Center. All the three launch centers are located in sparsely populated areas where the terrain is even and the field of vision is broad. Security, transport conditions and the influence of the axial rotation

  12. Geodetic Secor Satellite

    Science.gov (United States)

    1974-06-01

    simple, and had low-power lem. 17 14. Satellite Orientation . The satellite was designed to maintain a constant relationship between the antenna...the same satellite orientation . Further considerations were Th oscillations, however, when higher orbital ranges (500-2500 nautical miles) -, 3 a

  13. TC-2 Satellite Delivered

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    On April 18, 2005, TC-2, the second satellite of Double Star Program (DSP), which was jointly developed by CNSA and ESA, was approved to be delivered to the user after the on-board test and trial operation. The satellite is working well and the performance can meet the user's need. The satellite has collected large amount of valuable scientific data

  14. Ring current and radiation belts

    Science.gov (United States)

    Williams, D. J.

    1987-01-01

    Studies performed during 1983-1986 on the ring current, the injection boundary model, and the radiation belts are discussed. The results of these studies yielded the first observations on the composition and charge state of the ring current throughout the ring-current energy range, and strong observational support for an injection-boundary model accounting for the origins of radiation-belt particles, the ring current, and substorm particles observed at R less than about 7 earth radii. In addition, the results have demonstrated that the detection of energetic neutral atoms generated by charge-exchange interactions between the ring current and the hydrogen geocorona can provide global images of the earth's ring current and its spatial and temporal evolution.

  15. Magnetization of two coupled rings

    Energy Technology Data Exchange (ETDEWEB)

    Avishai, Y [Department of Physics and Ilse Katz Center for Nanotechnology, Ben Gurion University, Beer Sheva 84105 (Israel); Luck, J M [Institut de Physique Theorique, IPhT, CEA Saclay, and URA 2306, CNRS, 91191 Gif-sur-Yvette cedex (France)], E-mail: yshai@bgu.ac.il, E-mail: jean-marc.luck@cea.fr

    2009-05-01

    We investigate the persistent currents and magnetization of a mesoscopic system consisting of two clean metallic rings sharing a single contact point in a magnetic field. Many novel features with respect to the single-ring geometry are underlined, including the explicit dependence of wavefunctions on the Aharonov-Bohm fluxes, the complex pattern of two-fold and three-fold degeneracies, the key role of length and flux commensurability, and in the case of commensurate ring lengths the occurrence of idle levels which do not carry any current. Spin-orbit interactions, induced by the electric fields of charged wires threading the rings, give rise to a peculiar version of the Aharonov-Casher effect where, unlike for a single ring, spin is not conserved. Remarkably enough, this can only be realized when the Aharonov-Bohm fluxes in both rings are neither integer nor half-integer multiples of the flux quantum.

  16. Burnside Rings of Fusion Systems

    DEFF Research Database (Denmark)

    Reeh, Sune Precht

    , and we produce a basis for the Burnside ring that shares properties with the transitive sets for a finite group. We construct a transfer map from the p-local Burnside ring of the underlying p-group S to the p-local Burnside ring of F. Using such transfer maps, we give a new explicit construction...... of Burnside rings given by multiplication with the characteristic idempotent, and we show that this map is the transfer map previously constructed. Applying these results, we show that for every saturated fusion system the ring generated by all (non-idempotent) characteristic elements in the p-local double...... of the characteristic idempotent of F { the unique idempotent in the p-local double Burnside ring of S satisfying properties of Linckelmann and Webb. We describe this idempotent both in terms of fixed points and as a linear combination of transitive bisets. Additionally, using fixed points we determine the map...

  17. Black di-ring and infinite nonuniqueness

    CERN Document Server

    Iguchi, H; Iguchi, Hideo; Mishima, Takashi

    2007-01-01

    We show that the $S^1$-rotating black rings can be superposed by the solution generating technique. We analyze the black di-ring solution for the simplest case of multiple rings. There exists an equilibrium black di-ring where the conical singularities are cured by the suitable choice of physical parameters. Also there are infinite numbers of black di-rings with the same mass and angular momentum. These di-rings can have two different continuous limits of single black rings. Therefore we can transform the fat black ring to the thin ring with the same mass and angular momentum by way of the di-ring solutions.

  18. Saturn's Rings and Associated Ring Plasma Cavity: Evidence for Slow Ring Erosion

    Science.gov (United States)

    Farrell, W. M.; Kurth, W. S.; Gurnett, D. A.; Persoon, A. M.; MacDowall, R. J.

    2017-01-01

    We re-examine the radio and plasma wave observations obtained during the Cassini Saturn orbit insertion period, as the spacecraft flew over the northern ring surface into a radial distance of 1.3 Rs (over the C-ring). Voyager era studies suggest the rings are a source of micro-meteoroid generated plasma and dust, with theorized peak impact-created plasma outflows over the densest portion of the rings (central B-ring). In sharp contrast, the Cassini Radio and Plasma Wave System (RPWS) observations identify the presence of a ring-plasma cavity located in the central portion of the B-ring, with little evidence of impact-related plasma. While previous Voyager era studies have predicted unstable ion orbits over the C- ring, leading to field-aligned plasma transport to Saturns ionosphere, the Cassini RPWS observations do not reveal evidence for such instability-created plasma fountains. Given the passive ring loss processes observed by Cassini, we find that the ring lifetimes should extend >10(exp 9) years, and that there is limited evidence for prompt destruction (loss in <100 Myrs).

  19. ring og refleksion

    DEFF Research Database (Denmark)

    Wahlgren, B.; Rattleff, Pernille; Høyrup, S.

    State of the art inden for forskning om læring på arbejdspladsen samt gennemgang af læringsteori og refleksionsbegrebet hos Dewey, Dreyfus, Schön, Argyris, Kolb, Jarvis, Mezirow og Brookfield. Afsluttes med diskussion af syntetiseret model for læring på arbejdspladsen.......State of the art inden for forskning om læring på arbejdspladsen samt gennemgang af læringsteori og refleksionsbegrebet hos Dewey, Dreyfus, Schön, Argyris, Kolb, Jarvis, Mezirow og Brookfield. Afsluttes med diskussion af syntetiseret model for læring på arbejdspladsen....

  20. Why Are Ring Galaxies Interesting?

    CERN Document Server

    Higdon, James L

    2010-01-01

    Compared with ordinary spirals, the ISM in ring galaxies experiences markedly different physical conditions and evolution. As a result, ring galaxies provide interesting perspectives on the triggering/quenching of large scale star formation and the destructive effects of massive stars on molecular cloud complexes. We use high resolution radio, sub-millimeter, infrared, and optical data to investigate the role of gravitational stability in star formation regulation, factors influencing the ISM's molecular fraction, and evidence of peculiar star formation laws and efficiencies in two highly evolved ring galaxies: Cartwheel and the Lindsay-Shapley ring.

  1. Water changed the cities

    DEFF Research Database (Denmark)

    Elle, Morten; Jensen, Marina Bergen

    An improvement in water infrastructure and cleaning up the waters changed many harbour cities in Denmark at the beginning of the 90s. The harbour cities changed from drity, run-down industrial harbours to clean and attractive harbour dwelling creating new city centres and vital city areas...

  2. Water changed the cities

    DEFF Research Database (Denmark)

    Elle, Morten; Jensen, Marina Bergen

    An improvement in water infrastructure and cleaning up the waters changed many harbour cities in Denmark at the beginning of the 90s. The harbour cities changed from drity, run-down industrial harbours to clean and attractive harbour dwelling creating new city centres and vital city areas...

  3. Weighing Uranus’ Moon Cressida with the η Ring

    Science.gov (United States)

    Chancia, Robert O.; Hedman, Matthew M.; French, Richard G.

    2017-10-01

    The η ring is one of the narrow rings of Uranus, consisting of a dense core that is 1–2 km wide and a diffuse outer sheet spanning about 40 km. Its dense core lies just exterior to the 3:2 Inner Lindblad Resonance of the small moon Cressida. We fit the η ring radius residuals and longitudes from a complete set of both ground-based and Voyager stellar and radio occultations of the Uranian rings spanning 1977–2002. We find variations in the radial position of the η ring that are likely generated by this resonance, and take the form of a 3-lobed structure rotating at an angular rate equal to the mean motion of the moon Cressida. The amplitude of these radial oscillations is 0.667 ± 0.113 km, which is consistent with the expected shape due to the perturbations from Cressida. The magnitude of these variations provides the first measurement of the mass and density of the moon Cressida (m=(2.5+/- 0.4)× {10}17 kg and ρ =0.86+/- 0.16 g cm‑3) or, indeed, any of Uranus’ small inner moons. A better grasp of inner Uranian satellite masses will provide another clue to the composition, dynamical stability, and history of Uranus’ tightly packed system of small moons.

  4. On Weakly P.P. Rings

    Institute of Scientific and Technical Information of China (English)

    Xiang Yue-ming; Ouyang Lun-qun; Wang Shu-gui

    2015-01-01

    We introduce, in this paper, the right weakly p.p. rings as the generaliza-tion of right p.p. rings. It is shown that many properties of the right p.p. rings can be extended onto the right weakly p.p. rings. Relative examples are constructed. As applications, we also characterize the regular rings and the semisimple rings in terms of the right weakly p.p. rings.

  5. Meteorological satellite systems

    CERN Document Server

    Tan, Su-Yin

    2014-01-01

    “Meteorological Satellite Systems” is a primer on weather satellites and their Earth applications. This book reviews historic developments and recent technological advancements in GEO and polar orbiting meteorological satellites. It explores the evolution of these remote sensing technologies and their capabilities to monitor short- and long-term changes in weather patterns in response to climate change. Satellites developed by various countries, such as U.S. meteorological satellites, EUMETSAT, and Russian, Chinese, Japanese and Indian satellite platforms are reviewed. This book also discusses international efforts to coordinate meteorological remote sensing data collection and sharing. This title provides a ready and quick reference for information about meteorological satellites. It serves as a useful tool for a broad audience that includes students, academics, private consultants, engineers, scientists, and teachers.

  6. Theory of geostationary satellites

    CERN Document Server

    Zee, Chong-Hung

    1989-01-01

    Geostationary or equatorial synchronous satellites are a daily reminder of our space efforts during the past two decades. The nightly television satellite weather picture, the intercontinental telecommunications of television transmissions and telephone conversations, and the establishrnent of educational programs in remote regions on Earth are constant reminders of the presence of these satellites. As used here, the term 'geo­ stationary' must be taken loosely because, in the long run, the satellites will not remain 'stationary' with respect to an Earth-fixed reference frame. This results from the fact that these satellites, as is true for all satellites, are incessantly subject to perturbations other than the central-body attraction of the Earth. Among the more predominant pertur­ bations are: the ellipticity of the Earth's equator, the Sun and Moon, and solar radiation pressure. Higher harmonics of the Earth's potential and tidal effects also influence satellite motion, but they are of second­ order whe...

  7. System of cities dynamics in newly industrializing nations.

    Science.gov (United States)

    Meyer, D R

    1986-01-01

    Rapid industrialization in such countries as Korea, Malaysia, and Taiwan suggests that the complex functional structures of cities in the periphery may appear early in development. This paper proposes a 4-stage framework for the dynamics of a system of cities in a developing country undergoing industrialization and encompassing both nonindustrial and industrial development. The synthesis is assessed with evidence from the newly industrializing Asian nations of Korea, Malaysia, and Taiwan. The 4 stages of cities' industrial change include 1) increasing primacy with industrial satellites, 2) increasing primacy with industrial satellites and nodal towns on a transport network, 3) rapidly increasing primacy with rapidly growing industrial satellites and nodal towns on the transport network, and 4) decreasing primacy with slowly growing industrial satellites and rapidly growing peripheral industrial towns. The 4-stage synthesis suggests that economic development in the periphery may occur even while the primate city maintains its hegemony over control and coordination functions. Peripheral industrial growth does not challenge this hegemony. The growth of industrial cities is, instead, part of a process of regional specialization in which the low cost labor in the periphery becomes an attraction for industry. These stages are not inevitable. Government efforts are necessary to develop rural areas in terms of social improvements (education and health), capital infrastructure (transportation and utilities), and fair payments to farmers for their outputs. These seem to be the lessons learned from the industrialization process in Korea, Malaysia, and Taiwan.

  8. The eRHIC Ring-Ring Collider Design

    CERN Document Server

    Wang, Fuhua; Beebe-Wang, Joanne; Deshpande, Abhay A; Farkhondeh, Manouchehr; Franklin, Wilbur; Graves, William; Litvinenko, Vladimir N; MacKay, William W; Milner, Richard; Montag, Christoph; Ozaki, Satoshi; Parker, Brett; Peggs, Steve; Ptitsyn, Vadim; Roser, Thomas; Tepikian, Steven; Trbojevic, Dejan; Tschalär, C; Wang, Dong; Zolfaghari, Abbasali; Zwart, Townsend; van der Laan, Jan

    2005-01-01

    The eRHIC ring-ring collider is the main design option of the future lepton-ion collider at Brookhaven National Laboratory. We report the revisions of the ring-ring collider design features to the baseline design presented in the eRHIC Zeroth Design Report (ZDR). These revisions have been made during the past year. They include changes of the interaction region which are required from the modifications in the design of the main detector. They also include changes in the lepton storage ring for high current operations as a result of better understandings of beam-beam interaction effects. The updated collider luminosity and beam parameters also take into account a more accurate picture of current and future operational aspects of RHIC.

  9. Sizes and Shapes of Neptune's Inner Satellites

    Science.gov (United States)

    Karkoschka, E.

    2002-09-01

    I measured resolved images of the inner Neptunian satellites by Voyager 2. The best-fitting tri-axial radii are 48x30x26 km for Naiad, 54x50x26 km for Thalassa, 90x74x64 km for Despina, 102x92x72 km for Galatea, and 108x102x84 km for Larissa. These sizes are within uncertainty limits by Thomas and Veverka (1991) who provided a shape for Larissa (104x89 km), radii with assumed spherical shapes for Despina (74 km) and Galatea (79 km) and estimated radii based on assumed albedos for Naiad (29 km) and Thalassa (40 km). The uncertainties of the new radii are smaller. Estimates of volumes and masses of Naiad and Galatea need to be increased by some 50 percent, which is interesting since Galatea's gravity is considered to cause the unique arcs of Neptune's Adams ring. The moderately elongated shapes of the medium-sized satellites Despina and Galatea, and the strongly elongated shapes of the small satellites Naiad and Thalassa are typical for bodies of their size, although the shape of Thalassa is almost oblate (like a lens) while the shapes of other, strongly elongated satellites such as Naiad are closer to prolate (like a cigar). While previous uncertainties allowed the same reflectivity for the inner six Neptunian satellites, this is no longer true. There is a trend of albedos increasing with distance from Neptune, similar to the trend observed for the Uranian satellites. By estimating phase curves, I predict brighter albedos for inner six Neptunian satellites (0.07-0.10) than for the inner 10 Uranian satellites (0.05-0.07), opposite to previous estimates, which could be tested using recent images by the Hubble Space Telescope and ground-based observatories. The measured shapes of the inner Neptunian satellites cause orbital light curves, even if their surfaces lack spatial albedo variations. Indeed, photometry by Thomas and Veverka (1991) reveals amplitudes and phases of the light curves consistent with those inferred from the measured shapes, although most data are

  10. Temporal and spatial analysis of the expansion of a new coastal satellite city based on multi-dimensional satellite imagery%基于多时相卫星影像滨海卫星新城扩张的时空特征分析 以上海临港新城为例

    Institute of Scientific and Technical Information of China (English)

    张婷; 郑宗生

    2015-01-01

    Multi-dimensional Landsat data analyses (a direct comparison method based on pixel changes and a post-classiifcation comparison method based on spectral classiifcation, with a classiifcation accuracy of 85.83%) were used to assess development of a new satelite city, Lingang New City, in Shanghai, by detecting urban land use patterns over the period 2002–2015; the data were extracted from Thematic Mapper (TM) images. According to the results, the developed area increased by 2.12 times (by 18.745 km2) from 2002 to 2009, and by 0.9 times (by 24.945 km2) from 2009 to 2015, representing a 1.33 times increase between the two growth stages (2002–2009 and 2009–2015), and thus representing a period of rapid urban expansion. The study was conducted to identify the driving factors of urban expansion, by showing relationships between growth and social and economic statistics. As policies provide the overall guide for economic development, the driving forces in the region were considered to be social and economic factors, operating under the policy factor.%基于多时相Landsat卫星影像,综合运用基于像元变化的直接比较法和基于光谱分类的分类后比较法(分类精度达85.83%),提取出临港新城2002~2015年三个时相的城镇用地信息,分析城市扩张的变化特征,并通过相关社会经济统计资料对城市扩张的驱动因子进行相关研究。结果表明,2009年成建区面积比2002年增加18.745km2,为2002年的2.12倍,2015年成建区面积较2009年增加24.945km2,为2009年的0.9倍,年增长面积是前一阶段的1.33倍,处于城市空间扩张的第二大阶段,发展较为快速。运用单一因子相关分析法,计算得到经济因子和城镇用地面积的相关系数略大于人口因子与城镇用地面积的相关系数,且均与城镇用地面积成显著的正相关,而政策作为经济建设的导向推动因子,因此认为该区域驱动力主要表现在政策

  11. Comments on the interaction between the F ring system and its new discovered objects

    Science.gov (United States)

    Giuliatti Winter, S. M.; Ferreira Gonsalves, M. A.; Winter, O.; Cardozo Mourao, D.

    2005-08-01

    The arrival of the Cassini spacecraft to the saturnian system brought a huge amount of data. Among them there is the discovery of three satellites close to the F ring (S/2004 S3, S/2004 S4 and S/2004 S6) and two tenuous rings, one close to the satellite Prometheus (R 2004/S2) and other coorbital to the satellite Atlas (R 2004/ S1). Before the inclusion of these new bodies, this region already had some unexplained features. The F ring presents strands, kinks and clumps probably related to the close satellites Prometheus and Pandora and embedded moonlets. In this work we analysed the behaviour of the ring particles strands disturbed by a sample of small objects varying in size and orbital elements. The new discovered objects is part of this sample of objects. As an example, we showed that an object of 10km in radius forms a gap in the outer strand. There are no scattered particles, the gap is formed by particles which collide with the object. We also analysed a sample of hypothetical objects lying in the F ring region taking into account the perturbation of Prometheus, Pandora and the oblateness of Saturn. This analysis is primarily performed using the secular perturbation theory. Then we computed the Lyapunov characteristic exponent for these objects. These results are presented for a range of semi major axes and eccentricities. By using numerical simulation we can verify that the perturbation of Prometheus on the new rings causes a variation only in R 2004/S2. This perturbation is enough to open a gap and scatter particles in the direction of the F ring region. Acknowledgements: SMGW thanks FUNDUNESP, OCW thanks FUNDUNESP and CNPq, MAFG and DCM thank CAPES for the financial support.

  12. Clean Elements in Abelian Rings

    Indian Academy of Sciences (India)

    Angelina Y M Chin

    2009-04-01

    Let be a ring with identity. An element in is said to be clean if it is the sum of a unit and an idempotent. is said to be clean if all of its elements are clean. If every idempotent in is central, then is said to be abelian. In this paper we obtain some conditions equivalent to being clean in an abelian ring.

  13. DELPHI's Ring Imaging Cherenkov Chamber

    CERN Multimedia

    1989-01-01

    The hundreds of mirrors around this Ring Imaging Cherenkov Chamber reflect cones of light created by fast moving particles to a detector. The velocity of a particle can be measured by the size of the ring produced on the detector. DELPHI, which ran from 1989 to 2000 on the LEP accelerator, was primarily concerned with particle identification.

  14. Pyrimidine-pyridine ring interconversion

    NARCIS (Netherlands)

    Plas, van der H.C.

    2003-01-01

    This chapter discusses the pyrimidine-to-pyridine ring transformation and pyridine-to-pyrimidine ring transformation. In nucleophile-induced pyrimidine-to-pyridine rearrangements, two types of reactions can be distinguished depending on the structure of the nucleophile: (1) reactions in which the ni

  15. Supercharacter theories and Schur rings

    CERN Document Server

    Hendrickson, Anders O F

    2010-01-01

    Diaconis and Isaacs have defined the supercharacter theories of a finite group to be certain approximations to the ordinary character theory of the group. We make explicit the connection between supercharacter theories and Schur rings, and we provide supercharacter theory constructions which correspond to Schur ring constructions of Leung and Man and of Tamaschke.

  16. Contraceptive vaginal rings: a review.

    Science.gov (United States)

    Brache, Vivian; Faundes, Anibal

    2010-11-01

    Development efforts on contraceptive vaginal rings were initiated over 40 years ago based on two principles: the capacity of the vaginal epithelium to absorb steroids and the capacity of elastomers to release these hormones at a nearly constant rate. Numerous models of contraceptive vaginal rings (CVRs) have been studied, but only two have reached the market: NuvaRing, a combined ring that releases etonogestrel (ENG) and ethinylestradiol (EE), and Progering, a progesterone-releasing ring for use in lactating women. The main advantages of CVRs are their effectiveness (similar to or slightly better than the pill), ease of use without the need of remembering a daily routine, user's ability to control initiation and discontinuation, nearly constant release rate allowing for lower doses, greater bioavailability and good cycle control with the combined ring. The main disadvantages are related to the mode of delivery; CVRs may cause vaginal discharge and complaints, ring expulsion is not uncommon, the ring may be felt during coitus and vaginal insertion may be unpleasant for some women. The studies reviewed in this article provide evidence that CVRs are safe, effective and highly acceptable to women. There is no doubt that CVRs offer a new, effective contraceptive option to women, expanding their available choices of hormonal contraception.

  17. Constructions over localizations of rings

    Directory of Open Access Journals (Sweden)

    Alessandro Logar

    1987-11-01

    Full Text Available In this paper we construct a category of effective noetherian rings in which linear equations can be “solved”. This category is closed with respect to some important constructions like trascendental extensions, quotientations, finite products and localizations with respect to a large class of multiplicatively closed systems. Hence it gives a definition of “constructive” rings.

  18. The Search for Ringed Exoplanets

    Science.gov (United States)

    Kohler, Susanna

    2017-04-01

    Are planetary rings as common in our galaxy as they are in our solar system? A new study demonstrates how we might search for ringed exoplanets and then possibly finds one!Saturns Elsewhere?Artists illustration of the super ring system around exoplanet J1407b. This is the only exoplanet weve found with rings, but its not at all like Saturn. [Ron Miller]Our solar system is filled with moons and planetary rings, so it stands to reason that exoplanetary systems should exhibit the same features. But though weve been in the planet-hunting game for decades, weve only found one exoplanet thats surrounded by a ring system. Whats more, that system J1407b has enormous rings that are vastly different from the modest, Saturn-like rings that we might expect to be more commonplace.Have we not discovered ringed exoplanets just because theyre hard to identify? Or is it because theyre not out there? A team of scientists led by Masataka Aizawa (University of Tokyo) has set out to answer this question by conducting a systematic search for rings around long-period planet candidates.The transit light curve of KIC 10403228, shown with three models: the best-fitting planet-only model (blue) and the two best-fitting planet+ring models (green and red). [Aizawa et al. 2017]The Hunt BeginsWhy long-period planets? Rings are expected to be unstable as the planet gets closer to the central star. Whats more, the planet needs to be far enough away from the stars warmth for the icy rings to exist. The authors therefore select from the collection of candidate transiting planets 89 long-period candidates that might be able to host rings.Aizawa and collaborators then fit single-planet models (with no rings) to the light curves of these planets and search for anomalies curves that arent fit well by these standard models. Particularly suspicious characteristics include a long ingress/egress as the planet moves across the face of the star, and asymmetry of the transit shape.After applying a series of

  19. Formation of polar ring galaxies

    CERN Document Server

    Bournaud, F

    2003-01-01

    Polar ring galaxies are peculiar systems in which a gas rich, nearly polar ring surrounds an early-type or elliptical host galaxy. Two formation scenarios for these objects have been proposed: they are thought to form either in major galaxy mergers or by tidal accretion of the polar material from a gas rich donor galaxy. Both scenarios are studied through N-body simulations including gas dynamics and star formation. Constraints on physical parameters are drawn out, in order to determine which scenario is the most likely to occur. Polar ring galaxies from each scenario are compared with observations and we discuss whether the accretion scenario and the merging scenario account for observational properties of polar ring galaxies. The conclusion of this study is that the accretion scenario is both the most likely and the most supported by observations. Even if the merging scenario is rather robust, most polar ring galaxies are shown to be the result of tidal gas accretion events.

  20. Ionization cooling ring for muons

    Directory of Open Access Journals (Sweden)

    R. Palmer

    2005-06-01

    Full Text Available Practical ionization cooling rings could lead to lower cost or improved performance in neutrino factory or muon collider designs. The ring modeled here uses realistic three-dimensional fields. The performance of the ring compares favorably with the linear cooling channel used in the second U.S. Neutrino Factory Study. The normalized 6D emittance of an ideal ring is decreased by a factor of approximately 240, compared with a factor of only 15 for the linear channel. We also examine such real-world effects as windows on the absorbers and rf cavities and leaving empty lattice cells for injection and extraction. For realistic conditions the ring decreases the normalized 6D emittance by a factor of 49.

  1. Studies of methanol maser rings

    CERN Document Server

    Bartkiewicz, A; van Langevelde, H J; De Buizer, J M; Pihlström, Y

    2011-01-01

    We present the results of studies of a new class of 6.7 GHz methanol maser sources with a ring-like emission structure discovered recently with the EVN. We have used the VLA to search for water masers at 22 GHz and radio continuum at 8.4 GHz towards a sample of high-mass star forming regions showing a ring-like distribution of methanol maser spots. Using the Gemini telescopes we found mid-infrared (MIR) counterparts of five methanol rings with a resolution of 0."15. The centres of methanol maser rings are located within, typically, only 0."2 of the MIR emission peak, implying their physical relation with a central star. These results strongly support a scenario wherein the ring-like structures appear at the very early stage of massive star formation before either water-maser outflows or H II regions are seen.

  2. A Note on Clean Rings

    Institute of Scientific and Technical Information of China (English)

    Zhou Wang; Jianlong Chen

    2007-01-01

    Let R be a ring and g(x) a polynomial in C[x],where C=C(R) denotes the center of R.Camillo and Sim6n called the ring g(x)-clean if every element of R can be written as the sum of a unit and a root of g(x).In this paper,we prove that for a,b (E) C,the ring R is clean and b - a is invertible in R if and only if R is g1(x)-clean,where gl(x) = (x - a)(x - b).This implies that in some sense the notion of g(x)-clean rings in the Nicholson-Zhou Theorem and in the Camillo-Sim6n Theorem is indeed equivalent to the notion of clean rings.

  3. City health development planning.

    Science.gov (United States)

    Green, Geoff; Acres, John; Price, Charles; Tsouros, Agis

    2009-11-01

    The objective of this evaluation was to review the evolution and process of city health development planning (CHDP) in municipalities participating in the Healthy Cities Network organized by the European Region of the World Health Organization. The concept of CHDP combines elements from three theoretical domains: (a) health development, (b) city governance and (c) urban planning. The setting was the 56 cities which participated in Phase III (1998-2002) of the Network. Evidence was gathered from documents either held in WHO archives or made available from Network cities and from interviews with city representatives. CHDPs were the centrepiece of Phase III, evolving from city health plans developed in Phase II. They are strategic documents giving direction to municipalities and partner agencies. Analysis revealed three types of CHDP, reflecting the realpolitik of each city. For many cities, the process of CHDP was as important as the plan itself.

  4. Satellite estimates of urban development for hydrological modelling

    DEFF Research Database (Denmark)

    Kaspersen, Per Skougaard; Drews, Martin

    We investigate the applicability of medium resolution Landsat satellite imagery for mapping temporal changes in urban land cover in European cities for direct use in urban flood models. The overarching aim is to provide accurate and costand resource-efficient quantification of temporal changes...

  5. Satellite Tracking of Post-nesting Migration of Green Turtles

    Institute of Scientific and Technical Information of China (English)

    Wang Wenzhi; Wang Dongxiao; Wang Huajie; Song Xiaojun

    2002-01-01

    @@ During the period August 17-28, 2001, in collaboration with the Provincial Bureau of Oceanography & Fisheries of Guangdong and the South China Institute for Endangered Species, the South China Sea Institute of Oceanology, a CAS affiliate in the city of Guangzhou, conducted a sea turtle satellite tracking project at Haigui Bay (Fig. 1) in the vicinity of Gangkou Town, Huidong County, Guangdong Province.

  6. Hydrocarbons on the Icy Satellites of Saturn

    Science.gov (United States)

    Cruikshank, Dale P.

    2010-01-01

    The Visible-Infrared Mapping Spectrometer on the Cassini Spacecraft has obtained spectral reflectance maps of the satellites of Saturn in the wavelength region 0.4-5.1 micrometers since its insertion into Saturn orbit in late 2004. We have detected the spectral signature of the C-H stretching molecular mode of aromatic and aliphatic hydrocarbons in the low albedo material covering parts of several of Saturn's satellites, notably Iapetus and Phoebe (Cruikshank et al. 2008). The distribution of this material is complex, and in the case of Iapetus we are seeking to determine if it is related to the native grey-colored materials left as lag deposits upon evaporation of the ices, or represents in-fall from an external source, notably the newly discovered large dust ring originating at Phoebe. This report covers our latest exploration of the nature and source of this organic material.

  7. Did Saturn's rings form during the Late Heavy Bombardment ?

    CERN Document Server

    Charnoz, Sebastien; Dones, Luke H; Salmon, Julien

    2008-01-01

    The origin of Saturn\\' s massive ring system is still unknown. Two popular scenarios - the tidal splitting of passing comets and the collisional destruction of a satellite - rely on a high cometary flux in the past. In the present paper we attempt to quantify the cometary flux during the Late Heavy Bombardment (LHB) to assess the likelihood of both scenarios. Our analysis relies on the so-called Nice model of the origin of the LHB (Tsiganis et al., 2005; Morbidelli et al., 2005; Gomes et al., 2005) and on the size distribution of the primordial trans-Neptunian planetesimals constrained in Charnoz & Morbidelli (2007). We find that the cometary flux on Saturn during the LHB was so high that both scenarios for the formation of Saturn rings are viable in principle. However, a more detailed study shows that the comet tidal disruption scenario implies that all four giant planets should have comparable ring systems whereas the destroyed satellite scenario would work only for Saturn, and perhaps Jupiter. This is ...

  8. Black Hole Ringing, Quasinormal Modes, and Light Rings

    CERN Document Server

    Khanna, Gaurav

    2016-01-01

    Modelling of gravitational waves from binary black hole inspiral has played an important role in the recent observations of such signals. The late-stage ringdown phase of the gravitational waveform is often associated with the null particle orbit (\\light ring") of the black hole spacetime. With simple models we show that this link between the light ring and spacetime ringing is based more on the history of applications than on an actual constraining relationship. We also show, in particular, that a better understanding of the disassociation between the two, may be relevant to the astrophysically interesting case of rotating (Kerr) black holes.

  9. Neptunian Satellites observed with Keck AO system

    Science.gov (United States)

    Marchis, F.; Urata, R.; de Pater, I.; Gibbard, S.; Hammel, H. B.; Berthier, J.

    2004-05-01

    The Neptunian system was observed on 9 different nights between July 2002 and October 2003 with the 10-m Keck telescope on Mauna Kea, Hawaii, and its facility instrument NIRC2 coupled with the Adaptive Optics system. Data were recorded in J (1.2μ m), and H (2.2μ m) bands. The angular resolution achieved on a one-minute integration time image is 0.50 arcsec, corresponding to a spatial resolution of 1100 km. The images display small structures such as the rings (de Pater et al. 2004), clouds in the atmosphere (Gibbard et al. 2003), and inner satellites, mainly Proteus, Larissa, Galatea, Despina, and Thalassa. On the 40 images, the positions and intensities of the satellites detected were accurately measured fitting the signal with a gaussian profile. The center of Neptune was obtained by fitting the disk position with an ellipse. After correcting for the detector distortion, we compared the satellite positions with the predicted ones delivered by several ephemerides. We used the JPL (NEP016 + NEP022 + DE405) and two IMCCE ephemerides, an old version (VSOP87+Owen et al., 1991) and a more recent one (DE405+Le Guyader et al., 1993). All cases, we confirmed the presence of an apparent shift between the predicted and the observed positions. Table 1 (see http://astron.berkeley.edu/ fmarchis/Science/Neptune/Satellites/) summarizes the mean distance of the shift for satellites most frequently observed and the various ephemerides. In this presentation, we will report the positions of the satellites, and present their color and possible photometric variations derived from the observations. This work has been partially supported by the National Science Foundation Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under cooperative agreement No. AST - 9876783.

  10. Decline of sacred fir (Abies religiosa) in a forest park south of Mexico City.

    Science.gov (United States)

    Alvarado R, D; De Bauer, L I; Galindo A, J

    1993-01-01

    Decline of sacred fir (Abies religiosa) trees in the high elevation forest park, Desierto de los Leones, located south of Mexico City, is described. Trees located in the windward zone (exposed to air masses from Mexico City) were the most severely affected, especially trees at the distal ends of ravines. Examination of tree growth rings indicated decreases in ring widths for the past 30 years. Polluted air from Mexico City may be an important causal factor in fir decline. Drought, due to excessive removal of soil water, insects, mites and pathogens, and poor forest management are possible contributing and interactive factors in fir decline.

  11. Is the bell ringing?

    CERN Multimedia

    Francesco Poppi

    2010-01-01

    During the Nobel prize-winning UA1 experiment, scientists in the control room used to ring a bell if a particularly interesting event had occurred. Today, the “CMS Exotica hotline” routine produces a daily report that lists the exotic events that were recorded the day before.   Display of an event selected by the Exotica routine. Take just a very small fraction of the available data (max. 5%); define the events that you want to keep and set the parameters accordingly; run the Exotica routine and only look at the very few images that the system has selected for you. This is the recipe that a small team of CMS researchers has developed to identify the signals coming from possible new physics processes. “This approach does not replace the accurate data analysis on the whole set of data. However, it is a very fast and effective way to focus on just a few events that are potentially very interesting”, explains Maurizio Pierini (CERN), who developed the...

  12. Solar system history as recorded in the Saturnian ring structure

    Science.gov (United States)

    Alfven, H.

    1983-01-01

    Holberg's analysis of the Voyager Saturn photographs in reflected and transparent light, and occultation data of stars seen through the rings are discussed. A hyperfine structure, with 10,000 ringlets can be explained by the Baxter-Thompson negative diffusion. This gives the ringlets a stability which makes it possible to interpret them as fossils, which originated at cosmogonic times. It is shown that the bulk structure can be explained by the combined cosmogonic shadows of the satellites Mimas, Janus and the Shepherd satellites. This structure originated at the transition from the plasma phase to the planetesimal phase. The shadows are not simple void regions but exhibit a characteristic signature. Parts of the fine structure, explained by Holberg as resonances with satellites, are interpreted as cosmogonic shadow effects. However, there are a number of ringlets which can neither be explained by cosmogonic nor by resonance effects. Analysis of ring data can reconstruct the plasma-planetesimal transition with an accuracy of a few percent.

  13. Design of a ring resonator-based optical beam forming network for phased array receive antennas

    NARCIS (Netherlands)

    Klooster, van 't J.W.; Roeloffzen, C.G.H.; Meijerink, A.; Zhuang, L.; Marpaung, D.A.I.; Etten, van W.C.; Heideman, R.G.; Leinse, A.; Schippers, H.; Verpoorte, J.; Wintels, M.

    2008-01-01

    A novel squint-free ring resonator-based optical beam forming network (OBFN) for phased array antennas (PAA) is proposed. It is intended to provide broadband connectivity to airborne platforms via geostationary satellites. In this paper, we present the design of the OBFN and its control system. Our

  14. Mobile satellite communications handbook

    CERN Document Server

    Cochetti, Roger

    2014-01-01

    With a Preface by noted satellite scientist Dr. Ahmad Ghais, the Second Edition reflects the expanded user base for this technology by updating information on historic, current, and planned commercial and military satellite systems and by expanding sections that explain the technology for non-technical professionals.   The book begins with an introduction to satellite communications and goes on to provide an overview of the technologies involved in mobile satellite communications, providing basic introductions to RF Issues, power Issues, link issues and system issues. It describes

  15. Satellite communication antenna technology

    Science.gov (United States)

    Mittra, R. (Editor); Imbriale, W. A. (Editor); Maanders, E. J. (Editor)

    1983-01-01

    A general overview of current technology in the field of communication satellite antennas is presented. Among the topics discussed are: the design of multiple beam systems; frequency reuse; and polarization control of antenna measurements. Consideration is also given to: contour beam synthesis; dual shaped reflector synthesis; beam shaping; and offset reflector design. The applications of the above technologies to present and future generations of communications satellites is considered, with emphasis given to such systems as: the Intelsats; the Defense Satellite Communications System, (DSCS-III); Satellite Business System (SBS), and Comstar.

  16. Methods of satellite oceanography

    Science.gov (United States)

    Stewart, R. H.

    1985-01-01

    The theoretical basis for remote sensing measurements of climate and ocean dynamics is examined. Consideration is given to: the absorption of electromagnetic radiation in the atmosphere; scattering in the atmosphere; and satellite observations using visible light. Consideration is also given to: the theory of radio scatter from the sea; scatter of centimeter waves from the sea; and the theory of operation of synthetic aperture radars. Additional topics include: the coordinate systems of satellite orbits for oceanographic remote sensing applications; the operating features of the major U.S. satellite systems for viewing the ocean; and satellite altimetry.

  17. Ion Rings for Magnetic Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Greenly, John, B.

    2005-07-31

    This Final Technical Report presents the results of the program, Ion Rings for Magnetic Fusion, which was carried out under Department of Energy funding during the period August, 1993 to January, 2005. The central objective of the program was to study the properties of field-reversed configurations formed by ion rings. In order to reach this objective, our experimental program, called the Field-reversed Ion Ring Experiment, FIREX, undertook to develop an efficient, economical technology for the production of field-reversed ion rings. A field-reversed configuration (FRC) in which the azimuthal (field-reversing) current is carried by ions with gyro-radius comparable to the magnetic separatrix radius is called a field-reversed ion ring. A background plasma is required for charge neutralization of the ring, and this plasma will be confined within the ring's closed magnetic flux. Ion rings have long been of interest as the basis of compact magnetic fusion reactors, as the basis for a high-power accelerator for an inertial fusion driver, and for other applications of high power ion beams or plasmas of high energy density. Specifically, the FIREX program was intended to address the longstanding question of the contribution of large-orbit ions to the observed stability of experimental FRCs to the MHD tilt mode. Typical experimental FRCs with s {approx} 2-4, where s is the ratio of separatrix radius to ion gyro-radius, have been stable to tilting, but desired values for a fusion reactor, s > 20, should be unstable. The FIREX ring would consist of a plasma with large s for the background ions, but with s {approx} 1 for the ring ions. By varying the proportions of these two populations, the minimum proportion of large-orbit ions necessary for stability could be determined. The incorporation of large-orbit ions, perhaps by neutral-beam injection, into an FRC has been advanced for the purpose of stabilizing, heating, controlling angular momentum, and aiding the formation

  18. Ideals in Morita Rings and Morita Semigroups

    Institute of Scientific and Technical Information of China (English)

    Yu Qun CHEN; Yun FAN; Zhi Feng HAO

    2005-01-01

    We characterize the lattice of all ideals of a Morita ring (semigroup) when the corresponding pair of rings (semigroups) in the Morita context are Morita equivalent s-unital (like-unity) rings(semigroups).

  19. Jerusalem: City of Dreams, City of Sorrows

    Science.gov (United States)

    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…

  20. City Car = The City Car / Andres Sevtshuk

    Index Scriptorium Estoniae

    Sevtshuk, Andres, 1981-

    2008-01-01

    Massachusettsi Tehnoloogiainstituudi (MIT) meedialaboratooriumi juures tegutseva Targa Linna Grupi (Smart City Group) ja General Motorsi koostööna sündinud kaheistmelisest linnasõbralikust elektriautost City Car. Nimetatud töögrupi liikmed (juht William J. Mitchell, töögruppi kuulus A. Sevtshuk Eestist)

  1. City Car = The City Car / Andres Sevtshuk

    Index Scriptorium Estoniae

    Sevtshuk, Andres, 1981-

    2008-01-01

    Massachusettsi Tehnoloogiainstituudi (MIT) meedialaboratooriumi juures tegutseva Targa Linna Grupi (Smart City Group) ja General Motorsi koostööna sündinud kaheistmelisest linnasõbralikust elektriautost City Car. Nimetatud töögrupi liikmed (juht William J. Mitchell, töögruppi kuulus A. Sevtshuk Eestist)

  2. European Cities in the World City Network

    NARCIS (Netherlands)

    P. Taylor (Peter)

    2003-01-01

    textabstractThis is primarily an empirical paper that brings together selected results from the GaWC research programme. The latter studies inter-city relations at a global scale. Empirical research is based upon a model of world city network network formation as a product of the location strategies

  3. GRAVITATIONAL ACCRETION OF PARTICLES ONTO MOONLETS EMBEDDED IN SATURN's RINGS

    Energy Technology Data Exchange (ETDEWEB)

    Yasui, Yuki; Ohtsuki, Keiji [Department of Earth and Planetary Sciences, Kobe University, Kobe 657-8501 (Japan); Daisaka, Hiroshi, E-mail: y.yasui@whale.kobe-u.ac.jp, E-mail: ohtsuki@tiger.kobe-u.ac.jp [Graduate School of Commerce and Management, Hitotsubashi University, Tokyo 186-8601 (Japan)

    2014-12-20

    Using a local N-body simulation, we examine gravitational accretion of ring particles onto moonlet cores in Saturn's rings. We find that gravitational accretion of particles onto moonlet cores is unlikely to occur in the C ring and probably difficult in the inner B ring as well provided that the cores are rigid water ice. Dependence of particle accretion on ring thickness changes when the radial distance from the planet and/or the density of particles is varied: the former determines the size of the core's Hill radius relative to its physical size, while the latter changes the effect of self-gravity of accreted particles. We find that particle accretion onto high-latitude regions of the core surface can occur even if the rings' vertical thickness is much smaller than the core radius, although redistribution of particles onto the high-latitude regions would not be perfectly efficient in outer regions of the rings such as the outer A ring, where the size of the core's Hill sphere in the vertical direction is significantly larger than the core's physical radius. Our results suggest that large boulders recently inferred from observations of transparent holes in the C ring are not formed locally by gravitational accretion, while propeller moonlets in the A ring would be gravitational aggregates formed by particle accretion onto dense cores. Our results also imply that the main bodies of small satellites near the outer edge of Saturn's rings may have been formed in rather thin rings.

  4. Ring-Ringlet Interactions in Saturn's C Ring

    Science.gov (United States)

    Rappaport, N. J.

    1997-01-01

    The overall obejective of this work is to derive a theoretical model for the formation of gaps harboring isolated ringlets in order to explain the presence of such features in Saturn's C ring and Cassini division.

  5. Soft Congruence Relations over Rings

    Directory of Open Access Journals (Sweden)

    Xiaolong Xin

    2014-01-01

    Full Text Available Molodtsov introduced the concept of soft sets, which can be seen as a new mathematical tool for dealing with uncertainty. In this paper, we initiate the study of soft congruence relations by using the soft set theory. The notions of soft quotient rings, generalized soft ideals and generalized soft quotient rings, are introduced, and several related properties are investigated. Also, we obtain a one-to-one correspondence between soft congruence relations and idealistic soft rings and a one-to-one correspondence between soft congruence relations and soft ideals. In particular, the first, second, and third soft isomorphism theorems are established, respectively.

  6. Soft congruence relations over rings.

    Science.gov (United States)

    Xin, Xiaolong; Li, Wenting

    2014-01-01

    Molodtsov introduced the concept of soft sets, which can be seen as a new mathematical tool for dealing with uncertainty. In this paper, we initiate the study of soft congruence relations by using the soft set theory. The notions of soft quotient rings, generalized soft ideals and generalized soft quotient rings, are introduced, and several related properties are investigated. Also, we obtain a one-to-one correspondence between soft congruence relations and idealistic soft rings and a one-to-one correspondence between soft congruence relations and soft ideals. In particular, the first, second, and third soft isomorphism theorems are established, respectively.

  7. A Crowded City

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Over 4 million vehicles on road challenge Beijing’s city management Beijing, the city once known as the kingdom of bicycles, has become clogged with automobiles, the Beijing Municipal Government Publicity Office said on December 18.

  8. Build a Green City

    Institute of Scientific and Technical Information of China (English)

    XUYING; HAOXUE

    2005-01-01

    MA'ANSHAN,dubbed ""City of Iron and Steel,""is on the south bank of the Yangtze River in eastern Anhui Province, bordering Jiangsu Province. One of the city's most impressive features is its clean environment.

  9. EU Smart City Governance

    National Research Council Canada - National Science Library

    Carmela Gargiulo; Valentina Pinto; Floriana Zucaro

    2013-01-01

    .... The paper wants to outline which future EU draws for the city, through an integrated and contextual reading of addresses and strategies contained in the last documents, a future often suggested as Smart City...

  10. Saturn's rings revisited by the images of the CASSINI spacecraft: Dynamical evolution of the F ring and photometric study of the main rings

    Science.gov (United States)

    Deau, E.

    2007-12-01

    structure of the core is roughly stable on a scale of one year, but is very unstable on a shorter spatial and temporal scales, which is explained by multiple interactions with the satellite Prometheus and the ephemeris satellites. May be that these satellites came from the core and re-interact with him. Additional observations are necessary to refine this theory. In a second part, we were interested in photometry of the Saturn's rings i.e. to the way that the ring particles reflect sunlight. We were interested on the one hand in the opposition effect, an intense brightness observed in the main rings for the first time in 1878 by Müller at zero phase angle (the angle between the Sun, the rings and the observer), and which since was vainly explained by geometric optics theories (in particular by the means of the theory of shadow hiding). The use of models combining geometric optics and quantum optics (thanks to the theory of the coherent backscattering which allow to Philip Anderson to receive the Physics Nobel Prize in 1977) made it possible to understand a part of the opposition effect observed in the Saturn's rings. We show that five generally assertions on the shadow hiding and the coherent backscattering used by the community are false. Our study of the opposition surge caused by the coherent backscattering also showed than the taking into account of vectorial nature of light is necessary to understand this quantum phenomenon. In addition, we studied the overall photometric behaviour of the Saturn's rings by obtaining for the first time the full phase curves, going from 0° to 180° of phase angle, at several optical wavelengths. We showed that the rings have the widest range of albedo and anisotropy of all planetary objects joined together. This could be explained by size distributions, compositions and very different filling factors, which we determined thanks to some photometric models and which are in agreement with dynamic simulations and hydrodynamic analytical

  11. Revisiting city connectivity

    NARCIS (Netherlands)

    Mans, U.

    2014-01-01

    This article introduces a new perspective on city connectivity in order to analyze non-hub cities and their position in the world economy. The author revisits the different approaches discussed in the Global Commodity Chains (GCC), Global Production Networks (GPN) and World City Network (WCN) discou

  12. Imagineering the city

    NARCIS (Netherlands)

    van den Berg, M.; Paddison, R.; Hutton, T.

    2015-01-01

    Cities today are products. The urban experience is commodified into marketable items by urban entrepreneurs. Urban administrations, city marketers, politicians, local businesses and other actors all over the world are developing entrepreneurial strategies to sell their city. From "‘I ♥ New York"’ to

  13. The Creative Cities Network

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The Creative Cities Network, started by UNESCO in 2004, is one of the world’s highest-level non-governmental organizations in creative industry. The network focuses on the excellence of its member cities as its main product, and finds ways to maintain relevance in city life, local economy

  14. Vibration insensitive optical ring cavity

    Institute of Scientific and Technical Information of China (English)

    Miao Jin; Jiang Yan-Yi; Fang Su; Bi Zhi-Yi; Ma Long-Sheng

    2009-01-01

    The mounting configuration of an optical ring cavity is optimized for vibration insensitivity by finite element analysis. A minimum response to vertical accelerations is found by simulations made for different supporting positions.

  15. Autumn study on storage rings

    CERN Multimedia

    1974-01-01

    The first two weeks of October have seen storage ring people from accelerator Laboratories throughout the world at CERN to study the fundamental problems of very high energy protonproton colliding beam machines.

  16. Ring Model for Pneumatic Tires

    Institute of Scientific and Technical Information of China (English)

    危银涛; 范成建; 管迪华

    2002-01-01

    This paper reviews the state-of-the-art of the ring modeling method for tires, emphasizing the differences among the various tire ring models. A general tire ring model was then developed including all the nonlinear terms in the ring strain and the initial stresses induced by the internal pressure and rotation. The general equations of motion were derived from the Hamilton principle whth the geometric parameters for the model directly obtained from the tire design. The physical parameters were calculated from experimental mode parameters. A numerical example is given for a 195/70 R14-type tire. The analysis shows that the predicted natural frequencies and the tire mode shape agree well with experimental results.

  17. Perturbations of vortex ring pairs

    CERN Document Server

    Gubser, Steven S; Parikh, Sarthak

    2015-01-01

    We study pairs of co-axial vortex rings starting from the action for a classical bosonic string in a three-form background. We complete earlier work on the phase diagram of classical orbits by explicitly considering the case where the circulations of the two vortex rings are equal and opposite. We then go on to study perturbations, focusing on cases where the relevant four-dimensional transfer matrix splits into two-dimensional blocks. When the circulations of the rings have the same sign, instabilities are mostly limited to wavelengths smaller than a dynamically generated length scale at which single-ring instabilities occur. When the circulations have the opposite sign, larger wavelength instabilities can occur.

  18. Satellites of spiral galaxies

    Science.gov (United States)

    Zaritsky, Dennis; Smith, Rodney; Frenk, Carlos; White, Simon D. M.

    1993-01-01

    We present a survey of satellites around a homogeneous set of late-type spirals with luminosity similar to that of the Milky Way. On average, we find fewer than 1.5 satellites per primary, but we argue that we can treat the survey as an ensemble and so derive the properties of the halo of a 'typical' isolated spiral. The projected density profile of the ensemble falls off approximately as 1/r. Within 50 kpc the azimuthal distribution of satellites shows some evidence for the 'Holmberg effect', an excess near the minor axis of the primary; however, at larger projected distances, the distribution appears isotropic. There is a weak but significant correlation between the size of a satellite and its distance from its primary, as expected if satellites are tidally truncated. Neither Hubble type nor spectral characteristics correlate with apparent separation. The ensemble of satellites appears to be rotating at about 30 km/s in the same direction as the galactic disk. Satellites on prograde orbits tend to be brighter than those on retrograde orbits. The typical velocity difference between a satellite and its primary shows no clear dependence either on apparent separation, or on the rotation speed of the primary. Thus our survey demonstrates that isolated spiral galaxies have massive halos that extend to many optical radii.

  19. Communication satellite technology trends

    Science.gov (United States)

    Cuccia, Louis

    1986-01-01

    A chronology of space-Earth interconnectivity is presented. The Advanced Communications Technology Satellite (ACTS) system, Land Mobile Satellite, space-Earth antennas, impact of antenna size on coverage, intersatellite links are outlined. This presentation is represented by graphs and charts only.

  20. Roost site selection by ring-billed and herring gulls

    Science.gov (United States)

    Clark, Daniel E.; Destefano, Stephen; MacKenzie, Kenneth G.; Koenen, Kiana K. G.; Whitney, Jillian J.

    2016-01-01

    Gulls (Larus spp.) commonly roost in large numbers on inland and coastal waters, yet there is little information on how or where gulls choose sites for roosting. Roost site selection can lead to water quality degradation or aviation hazards when roosts are formed on water supply reservoirs or are close to airports. Harassment programs are frequently initiated to move or relocate roosting gulls but often have mixed results because gulls are reluctant to leave or keep returning. As such, knowledge of gull roost site selection and roosting ecology has applied and ecological importance. We used satellite telemetry and an information-theoretic approach to model seasonal roost selection of ring-billed (L. delawarensis) and herring gulls (L. argentatus) in Massachusetts, USA. Our results indicated that ring-billed gulls preferred freshwater roosts and will use a variety of rivers, lakes, and reservoirs. Herring gulls regularly roosted on fresh water but used salt water roosts more often than ring-billed gulls and also roosted on a variety of land habitats. Roost modeling showed that herring and ring-billed gulls selected inland fresh water roosts based on size of the water body and proximity to their last daytime location; they selected the largest roost closest to where they ended the day. Management strategies to reduce or eliminate roosting gulls could identify and try to eliminate other habitat variables (e.g., close-by foraging sites) that are attracting gulls before attempting to relocate or redistribute (e.g., through hazing programs) roosting birds.

  1. Synlig læring

    DEFF Research Database (Denmark)

    Brandsen, Mads

    2017-01-01

    Introduktionen af John Hatties synlig læring i den danske skoleverden møder stadig meget kritik. Mange lærere og pædagoger oplever synlig læring som en tornado, der vil opsuge og ødelægge deres særlige danske udgave af den kontinentale dannelsestænkning, didaktik og pædagogik. Spørgsmålet er om...

  2. Commuting Π-regular rings

    Directory of Open Access Journals (Sweden)

    Shervin Sahebi

    2014-05-01

    Full Text Available ‎$R$ is called commuting regular ring (resp‎. ‎semigroupif‎ for each $x,y\\in R$ there exists $a\\in R$‎ such that$xy=yxayx$‎. ‎In this paper‎, ‎we introduce the concept of‎‎commuting $\\pi$-regular rings (resp‎. ‎semigroups and‎‎study various properties of them.

  3. 北京西三环地区不同粒径大气颗粒物中有机脂肪酸的污染特性%Distribution Characteristics of Organic Aliphatic Acids in Airborne Particles with Different Sizes in the Area of the 3rd West Ring Road in Beijing City

    Institute of Scientific and Technical Information of China (English)

    何翔; 钱枫; 李峣

    2013-01-01

    Particulate samples were collected by the multi-stage impactor sampler and classitied into five grades by their sizes trom January to July in 2012 in the area of the 3rd west ring road in Beijing City.The organic aliphatic acids in the samples were determined by GC-MS after the pretreatment of solvent extraction and derivation.Twenty one monocarboxylic aliphatic acids and seven dicarboxylic aliphatic acids were separately determined.The results showed that both acids had a tendency to concentrate in ultrafine particles which were smaller than 0.69 μm.For the two acids,ρ<0.69 (∑21 MOA) and ρ<0.69 (∑7DIA) accounted for 30.0% and 32.5% of the concentration of all stages particles,respectively.The monthly variations with concentrations of monocarboxylic aliphatic acids and dicarboxylic aliphatic acids appeared quite different.ρ(∑21 MOA) were much higher obviously for January and February and were the second in March.However,the highest values of ρ(∑7DIA) appeared from May to July.There were obvious differences in composition characteristics of the two acids.The monocarboxylic aliphatic acids in the ranges C10 ~ C24 had a significant even number predominances,while dicarboxylic aliphatic acids presented no parity preponderance.For the fatty acids,the concentration of hexadecanoic acid was the highest followed by octadecanoic acid; Nonandioic acid presented the highest concentration in dicarboxylic acids.Preliminary analysis based on the ratios of C18/C16 and the CPI showed that monocarboxylic aliphatic acids mainly caused by human activities such as coal combustion,vehicle exhaust and cooking emission.For instance,the most important source of fatty acids was coal burning in January and February.%2012年1-7月在北京市西三环航天桥地区,用大流量分级采样器分5级采集大气颗粒物样品,采用溶剂提取和衍生化方法对样品进行前处理,利用GC-MS分析不同粒径颗粒物中的有机脂肪酸.结果表明:

  4. History of Neptune's Ring Arcs

    Science.gov (United States)

    Esposito, L. W.; Colwell, J. E.; Canup, R. M.

    1997-07-01

    The recent dynamical calculations for Neptune's Adams ring arcs by Foryta and Sicardy (1996) and Hanninen and Porco (1997) determine the basic evolutionary parameters for this system. The ring evolution is dominated by stochastic events, particularly chaotic motion that causes a migration between the corotation sites (FS96) and collisions near quadrature (HP97). A basic problem is that the high velocity collisions that produce the dusty arcs at the Galatea corotation resonances rapidly depopulate these sites (Colwell and Esposito 1990). With the new results in hand for the evolution of the ring particles over periods of less than a century, we can now calculate the long-term stochastic evolution of the Adams ring. Using a finite Markov chain as a model for this stochastic process, we follow the suggestion by FS96 that corotation sites provide preferential locations for accretion. A more general conclusion is that the longitudinal concentration of material in a few nearby sites (and that the majority of the Adams ring material is residing there) requires either an exceedingly recent event (EC92) or that the corotation sites be absorbing states of the Markov chain.In the latter case, the competing processes of chaotic diffusion and frustrated accretion can provide the arc and clump features as recurrent transient events near the Roche limit. Similar phenomena would be expected for Saturn's F and G rings.

  5. The ring of the narcissist.

    Science.gov (United States)

    Shengold, L

    1995-12-01

    The author has not attempted a complete exposition of the meaning of rings--which can refer to and symbolise many aspects of relationships with other human beings from 'transitional objects' of early development (Winnicott) to all sorts of bonds of loyalty, friendship, and love in the life of the child and the adult. He stresses the meanings of the ring from the point of view of early narcissistic development--the 'body ego' time of early development in which symbolism (in Freud's sense) develops. The clinical and literary examples therefore illustrate the use of rings as magical narcissistic symbols--part subject and part object--derived developmentally from the body ego and ultimately from the body sphincters. Endowed with these regressive primitive meanings, rings are felt to have magical powers that can either preserve or destroy, and that can control emotions in the self and in others. In the course of ordinary or pathological narcissistic regressions, rings (consciously associated with many positive feelings and achievements) also partake, in so far as they are 'Freudian' symbols, of qualities associated with developmentally early defensive mechanisms and modes of psychic functioning (projection, introjection; idealisation, devaluation). In the cases cited, rings seemed specifically associated with (and to symbolise) sphincteric (largely anal) narcissistic defensiveness--the mind functioning as an emotional sphincteric counterpart primarily deadening and distancing affect but intermittently letting through primitive rage and primal polymorphous perverse sexual impulses.

  6. Collar nut and thrust ring

    Science.gov (United States)

    Lowery, Guy B.

    1991-01-01

    A collar nut comprises a hollow cylinder having fine interior threads at one end for threadably engaging a pump mechanical seal assembly and an inwardly depending flange at the other end. The flange has an enlarged portion with a groove for receiving an O-ring for sealing against the intrusion of pumpage from the exterior. The enlarged portion engages a thrust ring about the pump shaft for crushing a hard O-ring, such as a graphite O-ring. The hard O-ring seals the interior of the mechanical seal assembly and pump housing against the loss of lubricants or leakage of pumpage. The fine threads of the hollow cylinder provide the mechanical advantage for crushing the hard O-ring evenly and easily with a hand tool from the side of the collar nut rather than by tightening a plurality of bolts from the end and streamlines the exterior surface of the mechanical seal. The collar nut avoids the spatial requirements of bolt heads at the end of a seal and associated bolt head turbulence.

  7. Size distribution of particles in Saturn's rings, missed moonlets and misinterpretation of Chariklo rings

    CERN Document Server

    Gorkavyi, Nick

    2016-01-01

    Brilliantov et al. (PNAS, 2015) propose a model for the size distribution ~R^-3 for small particles with radius R and ~exp(-(R/Rc)^3) for large particles, where Rc=5.5 m. In 1989 Longaretti found analytically ~R^-3 for small particles and R^-6 for large ones (2). The law R^-6 also describes moonlets with size ~ 0.1-1 km. Cut-off law from Brilliantov et al. model does not describe moonlets and requires new mechanism for the origin of ~ 1 km size bodies. This model does not take into account the key effects of self-gravitation of large particles and differential rotation of the rings. Longaretti used a more accurate model of destruction of particles: "A relative increase of the erosion/destruction rate of the large particles must take place, because these particles have relative velocities of collision larger than the dispersion velocity, due to the differential Keplerian motion". The new model does not explain the difference between the rings and the satellites and the authors suggest that their calculations a...

  8. VLT/NACO observations of Neptune's ring arcs

    Science.gov (United States)

    Renner, S.; Sicardy, B.; Souami, D.; Dumas, C.

    2011-10-01

    We present NACO adaptative optics observations of Neptune's ring arcs at 2.2 μm (K band), taken with the VLT-Yepun telescope in August 2007. We give improved mean motion values for the arcs and Galatea, thus confirming the mismatch between the arcs' position and the location of the 42:43 corotation inclination resonance. We compare the photometry of the arcs with previous observations. We finally use the data to constrain the masses and positions of the coorbital satellites which could confine the arcs, while allowing a slow evolution of the system.

  9. Perspective View with Landsat Overlay, Salt Lake City, Utah

    Science.gov (United States)

    2002-01-01

    Most of the population of Utah lives just west of the Wasatch Mountains in the north central part of the state. This broad east-northeastward view shows that region with the cities of Ogden, Salt Lake City, and Provo seen from left to right. The Great Salt Lake (left) and Utah Lake (right) are quite shallow and appear greenish in this enhanced natural color view. Thousands of years ago ancient Lake Bonneville covered all of the lowlands seen here. Its former shoreline is clearly seen as a wave-cut bench and/or light colored 'bathtub ring' at several places along the base of the mountain front - evidence seen from space of our ever-changing planet.This 3-D perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM), a Landsat 5 satellite image mosaic, and a false sky. Topographic expression is exaggerated four times.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif

  10. Influence of transportation policy on the multi-mode transportation choice behavior between megacity and satellite city and the system benefit estimation%交通政策对主卫城间多模式交通选择行为的影响及系统效益测算

    Institute of Scientific and Technical Information of China (English)

    马书红; 孙言涵

    2015-01-01

    交通政策和管理措施的实施会对主卫城间多模式复合交通出行行为选择方式和系统整体效益产生影响,需要科学评估其影响程度,为城间交通模式的协调配置提供参考。在对城间交通模式及其出行行为特征进行分析的基础上,将基于随机效用理论的MNL模型和基于Logsun 差异的效益测算方法相结合,针对城间4种典型的交通模式,通过构建基准情景和多种可能情景,测算了不同交通政策实施对城间交通出行选择的影响和出行者效益。结果表明,实施公交优先(减少乘客出行时间)对城间交通出行选择行为的影响较大,并具有较明显的系统经济效益,在协调城间交通模式配置时可优先考虑。%Transport policy and management measures have an influence on muti-mode transporta-tion choice behavior between megacity and satellite city and the system’s whole benefits , which makes it necessary to make a scientific evaluation of the influence and provide a reference for the coordinated con-figuration of the intercity transportation mode .Based on the analysis of intercity transportation mode and the characteristics of travel behavior , MNL on the basis of random utility theory and benefit estimation method on the basis of Logsum differences were combined together .According to the four typical intercity traffic patterns, the influence of the different transportation policies on the intercity travel choice and travelers'benefits were estimated by constructing a baseline scenario and a variety of possible scenarios . The results show that the implementation of bus priority policy ( to reduce passenger travel time ) has a significant impact on intercity travelers'behavior choice and achieves obvious system economic benefits , which should be given priority in the coordination of intercity transportation mode .

  11. Me, the City

    Directory of Open Access Journals (Sweden)

    Konstantin Lidin

    2014-09-01

    Full Text Available The search for identity of cities looks rather urgent and attracts attention of many researchers. Addressing this issue, the article draws an analogy between a human person and a city. Like a city, a human being needs to comprehend his self-identity in order to resist depressive tendencies. It is shown that a person’s depressive symptoms are similar to those of cities. The city identity necessary to resist depression can be searched for both historically and geographically. The historical aspect consists of local myths and legends about the city and the citizens. The geographical aspect of identity comprises features of the terrain, climate, flora and fauna of the region where the city is located.

  12. Cities as development drivers

    DEFF Research Database (Denmark)

    Johnson, Bjørn; Poulsen, Tjalfe; Hansen, Jens Aage

    2011-01-01

    There is a strong connection between economic growth and development of cities. Economic growth tends to stimulate city growth, and city economies have often shaped innovative environments that in turn support economic growth. Simultaneously, social and environmental problems related to city growth...... can be serious threats to the realization of the socio-economic contributions that cities can make. However, as a result of considerable diversity of competences combined with interactive learning and innovation, cities may also solve these problems. The ‘urban order’ may form a platform...... for innovative problem solving and potential spill-over effects, which may stimulate further economic growth and development. This paper discusses how waste problems of cities can be transformed to become part of new, more sustainable solutions. Two cases are explored: Aalborg in Denmark and Malmö in Sweden...

  13. Virtual 3d City Modeling: Techniques and Applications

    Science.gov (United States)

    Singh, S. P.; Jain, K.; Mandla, V. R.

    2013-08-01

    3D city model is a digital representation of the Earth's surface and it's related objects such as Building, Tree, Vegetation, and some manmade feature belonging to urban area. There are various terms used for 3D city models such as "Cybertown", "Cybercity", "Virtual City", or "Digital City". 3D city models are basically a computerized or digital model of a city contains the graphic representation of buildings and other objects in 2.5 or 3D. Generally three main Geomatics approach are using for Virtual 3-D City models generation, in first approach, researcher are using Conventional techniques such as Vector Map data, DEM, Aerial images, second approach are based on High resolution satellite images with LASER scanning, In third method, many researcher are using Terrestrial images by using Close Range Photogrammetry with DSM & Texture mapping. We start this paper from the introduction of various Geomatics techniques for 3D City modeling. These techniques divided in to two main categories: one is based on Automation (Automatic, Semi-automatic and Manual methods), and another is Based on Data input techniques (one is Photogrammetry, another is Laser Techniques). After details study of this, finally in short, we are trying to give the conclusions of this study. In the last, we are trying to give the conclusions of this research paper and also giving a short view for justification and analysis, and present trend for 3D City modeling. This paper gives an overview about the Techniques related with "Generation of Virtual 3-D City models using Geomatics Techniques" and the Applications of Virtual 3D City models. Photogrammetry, (Close range, Aerial, Satellite), Lasergrammetry, GPS, or combination of these modern Geomatics techniques play a major role to create a virtual 3-D City model. Each and every techniques and method has some advantages and some drawbacks. Point cloud model is a modern trend for virtual 3-D city model. Photo-realistic, Scalable, Geo-referenced virtual 3

  14. Accretion in Saturn's F Ring

    Science.gov (United States)

    Meinke, B. K.; Esposito, L. W.; Stewart, G.

    2012-12-01

    Saturn's F ring is the solar system's principal natural laboratory for direct observation of accretion and disruption processes. The ring resides in the Roche zone, where tidal disruption competes with self-gravity, which allows us to observe the lifecycle of moonlets. Just as nearby moons create structure at the B ring edge (Esposito et al. 2012) and the Keeler gap (Murray 2007), the F ring "shepherding" moons Prometheus and Pandora stir up ring material and create observably changing structures on timescales of days to decades. In fact, Beurle et al (2010) show that Prometheus makes it possible for "distended, yet gravitationally coherent clumps" to form in the F ring, and Barbara and Esposito (2002) predicted a population of ~1 km bodies in the ring. In addition to the observations over the last three decades, the Cassini Ultraviolet Imaging Spectrograph (UVIS) has detected 27 statistically significant features in 101 occultations by Saturn's F ring since July 2004. Seventeen of those 27 features are associated with clumps of ring material. Two features are opaque in occultation, which makes them candidates for solid objects, which we refer to as Moonlets. The 15 other features partially block stellar signal for 22 m to just over 3.7 km along the radial expanse of the occultation. Upon visual inspection of the occultation profile, these features resemble Icicles, thus we will refer to them as such here. The density enhancements responsible for such signal attenuations are likely due to transient clumping of material, evidence that aggregations of material are ubiquitous in the F ring. Our lengthy observing campaign reveals that Icicles are likely transient clumps, while Moonlets are possible solid objects. Optical depth is an indicator of clumping because more-densely aggregated material blocks more light; therefore, it is natural to imagine moonlets as later evolutionary stage of icicle, when looser clumps of material compact to form a feature that appears

  15. Beginnings of Satellite Navigation

    Directory of Open Access Journals (Sweden)

    Miljenko Solarić

    2008-05-01

    Full Text Available The first satellite navigation system called the Navy Navigation Satellite System (NNSS or TRANSIT was planned in the USA in 1958. It consisted of 5-6 artificial Earth satellites, was set in motion for the USA military in 1964, and in 1967 for civilian purposes. The frequency shift of received radio waves emitted from the satellite and caused by the Doppler effect was measured. The TRANSIT satellite speed of approaching or moving away was derived from that; the TRANSIT satellites emmited also their own coordinates. Then the ship's position was determined by an intersection of three hyperboloids, which were determined from differences of distances in three time intervals. Maintenance of this navigation system was stopped in 1996, but it is still being used in the USA Navy for exploring the ionosphere. Furthermore, results of Doppler measurements in international projects at the Hvar Observatory from 1982 and 1983. This was the first time in Croatia and the former country that the coordinates of the Hvar Observatory were determined in the unique world coordinate system WGS'72. The paper ends with a brief representation of the Tsiklon Doppler navigation system produced in the former Soviet Union, and there is a list of some of numerous produced and designed satellite navigation systems.Ključne riječi

  16. Double acting stirling engine piston ring

    Science.gov (United States)

    Howarth, Roy B.

    1986-01-01

    A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

  17. An interesting natural phenomenon - giant rings on Lake Baikal ice

    Science.gov (United States)

    Kouraev, Alexei; Shimaraev, Michail; Remy, Frederique; Ivanov, Andrei; Golubov, Boris

    2010-05-01

    Starting from May 2009 scientific community and large public have been puzzled by the formation of giant rings on Baikal ice. These rings (diameter 5-7 km, thickness of dark layer - 1 - 1.8 km) have almost perfect circular shape what makes them so interesting and attractive not only to scientists, but also for large public. . The rings have been observed since 1999 by various satellites and sensors (AVHRR, MODIS, Landsat, SPOT) as early as 1999 but probably also in 1984 and 1994 (Shuttle missions). These rings are usually well observed in April, when snow cover is thin or absent. Rings have been observed in the southern tip of the lake (2009), and in three places in the central part: near Krestovskiy cape (1999, 2003, 2005 and 2008), near Turka (2008), and near Cape Nizhnee Izgolovye (2009). All these places are located in the region of steep bottom topography, over depths of more than 500 m. According to in situ measurements done by the Limnological Institute in Irkutsk in 2009, ice thickness is about 70 cm in the center and on the outside of the ring, and 40 cm in the ring itself. It is known that the Baikal lake has important hydrothermal activity, and there are numerous observations of gas (methane etc) seepage from its 7 km-thick layer of bottom sediments. Local-scale absence of ice cover (steamthroughs or "propariny") is typical for some places in Lake Baikal. They result from gas emissions (associated with rise of warm water), near capes and straits (due to better vertical mixing), thermal sources, outlets of large rivers. Often they are observed near Capes Big and Small Kadil'niy, and in the Olkhonskiye vorota strait. However they size ranges from just a half a meter to several hundreds of meters (but not several kilometers) and this could not be an explanation for the formation of giant rings. We present several existing hypotheses of the origin of these rings including gas emission, heat flux, cyclonic subsurface currents and mega-bubble formation due to

  18. Extensions and Pullbacks in QB-rings

    OpenAIRE

    Ara, Pere; Pedersen, Gert K.; Perera, Francesc

    2001-01-01

    We prove a new extension result for $QB-$rings that allows us to examine extensions of rings where the ideal is purely infinite and simple. We then use this result to explore various constructions that provide new examples of $QB-$rings. More concretely, we show that a surjective pullback of two $QB-$rings is usually again a $QB-$ring. Specializing to the case of an extension of a semi-prime ideal $I$ of a unital ring $R$, the pullback setting leads naturally to the study of rings whose multi...

  19. The ribbon of the rings: the stability of the rings

    Science.gov (United States)

    Florinski, V.

    2016-11-01

    The astounding result of the Voyager 1 observations in the outer heliosheath region is the Kolmogorov-like spectrum of magnetic fluctuations, consistent with the ambient spectrum of interstellar turbulence deduced from remote sensing. Such quiet conditions appear to be incompatible with the ionization of the neutral solar wind hydrogen atoms by charge exchange, which would generate abundant turbulent fluctuations due to an instability of the resulting proton ring. Here we revisit the problem of stability of ring and shell distributions embedded in a warm plasma characteristic of the outer heliosheath. We show that ion rings with parallel velocity dispersion between a few km/s and the core thermal speed are stable, while those outside these bounds are subject to magnetic-fluctuation-producing left- and righthanded instabilities. Wave generation by the instability is too efficient to be transported to shorter scales and converted into heat by the turbulent cascade.

  20. Application of ring tectonic theory to Mercury and other solar system bodies

    Science.gov (United States)

    Mckinnon, W. B.

    1981-01-01

    It is pointed out that multiringed structures, by their presence or absence, provide a powerful tool for deciphering the thermal histories of the solid planets. The theory of ring tectonics considered by Melosh and McKinnon (1978) and Melosh et al. (1980) establishes the framework of that undertaking. The present investigation has the objective to apply this conceptualization in detail to the multiringed basins on Mercury, taking into account also a brief review concerning the current state of understanding of ring tectonics on the moon, Mars, earth, Ganymede, and Callisto. The small, icy satellites of Saturn are also discussed. The mechanics of multiple ring formation are related to the collapse of the transient basin cavity when the excavation depth and lithosphere thickness are comparable. Attention is given to the Caloris Basin on Mercury, the peak ring basins on Mercury, and the Argyre Basin on Mars.

  1. Application of ring tectonic theory to Mercury and other solar system bodies

    Science.gov (United States)

    Mckinnon, W. B.

    1981-01-01

    It is pointed out that multiringed structures, by their presence or absence, provide a powerful tool for deciphering the thermal histories of the solid planets. The theory of ring tectonics considered by Melosh and McKinnon (1978) and Melosh et al. (1980) establishes the framework of that undertaking. The present investigation has the objective to apply this conceptualization in detail to the multiringed basins on Mercury, taking into account also a brief review concerning the current state of understanding of ring tectonics on the moon, Mars, earth, Ganymede, and Callisto. The small, icy satellites of Saturn are also discussed. The mechanics of multiple ring formation are related to the collapse of the transient basin cavity when the excavation depth and lithosphere thickness are comparable. Attention is given to the Caloris Basin on Mercury, the peak ring basins on Mercury, and the Argyre Basin on Mars.

  2. The dynamics of rings around small, irregular bodies

    Science.gov (United States)

    Sicardy, Bruno

    2017-06-01

    Stellar occultations revealed the presence of two dense rings around the Centaur object (10199) Chariklo (Braga-Ribas et al., Nature 508, 72, 2014). This is the first ring system discovered around an object that is not a giant planet, suggesting that rings may exist around numerous bodies in the solar system. Chariklo's rings roughly reside at the outer limit of the Roche zone of the body. Moreover, the main ring has sharp edges, which call for the presence of putative shepherd satellites. Those characteristics give an image of Chariklo's rings that are rather similar, in terms of dynamics, to those surrounding the gaseous planets.An important difference exists, however, between giant planets and small bodies: the formers are highly axisymmetric, while the latters can support mass anomalies (eg surface topographic features) or non-spherical shapes (eg an ellipsoidal figure of equilibrium) that involve masses, relative to the body itself, as large as 10-4-10-3.We investigate the effect of non-axisymmetric terms in the potential of the body upon a collisional debris disk that initially surrounds a small irregular body. We show that the corotation points being maxima of energy, dissipative collisions remove the particles from the corotation zone over short time scales (< 106 years). Moreover, the Lindblad resonances inside the corotation radius create torques that drive the particles onto the surface of the central body. Conversely, the outer Lindblad resonances push the disk material beyond the outer 3/2 and 2/1 Lindblad resonances.Taking as an example Chariklo's ring system, for which recent data have been obtained from stellar occultations, we show that the Lindblad resonant torques actuate over short time scales (< 106 years). This general picture offers a natural explanation of the presence of dense rings at the outer limit of Chariklo's Roche zone, and their absence closer to the body.The work leading to this results has received funding from the European

  3. City Carbon Footprint Networks

    Directory of Open Access Journals (Sweden)

    Guangwu Chen

    2016-07-01

    Full Text Available Progressive cities worldwide have demonstrated political leadership by initiating meaningful strategies and actions to tackle climate change. However, the lack of knowledge concerning embodied greenhouse gas (GHG emissions of cities has hampered effective mitigation. We analyse trans-boundary GHG emission transfers between five Australian cities and their trading partners, with embodied emission flows broken down into major economic sectors. We examine intercity carbon footprint (CF networks and disclose a hierarchy of responsibility for emissions between cities and regions. Allocations of emissions to households, businesses and government and the carbon efficiency of expenditure have been analysed to inform mitigation policies. Our findings indicate that final demand in the five largest cities in Australia accounts for more than half of the nation’s CF. City households are responsible for about two thirds of the cities’ CFs; the rest can be attributed to government and business consumption and investment. The city network flows highlight that over half of emissions embodied in imports (EEI to the five cities occur overseas. However, a hierarchy of GHG emissions reveals that overseas regions also outsource emissions to Australian cities such as Perth. We finally discuss the implications of our findings on carbon neutrality, low-carbon city concepts and strategies and allocation of subnational GHG responsibility.

  4. Intrinsic structure in Saturn's rings

    Science.gov (United States)

    Albers, N.

    2015-10-01

    Saturn's rings are the most prominent in our Solar system and one example of granular matter in space. Dominated by tides and inelastic collisions the system is highly flattened being almost 300000km wide while only tens of meters thick. Individual particles are composed of primarily water ice and range from microns to few tens of meters in size. Apparent patterns comprise ringlets, gaps, kinematic wakes, propellers, bending waves, and the winding spiral arms of density waves. These large-scale structures are perturbations foremost created by external as well as embedded moons. Observations made by the Cassini spacecraft currently in orbit around Saturn show these structures in unprecedented detail. But high-resolution measurements reveal the presence of small-scale structures throughout the system. These include self-gravity wakes (50-100m), overstable waves (100-300m), subkm structure at the A and B ring edges, "straw" and "ropy" structures (1-3km), and the C ring "ghosts". Most of these had not been anticipated and are found in perturbed regions, driven by resonances with external moons, where the system undergoes periodic phases of compression and relaxation that correlate with the presence of structure. High velocity dispersion and the presence of large clumps imply structure formation on time scales as short as one orbit (about 10 hours). The presence of these intrinsic structures is seemingly the response to varying local conditions such as internal density, optical depth, underlying particle size distribution, granular temperature, and distance from the central planet. Their abundance provides evidence for an active and dynamic ring system where aggregation and fragmentation are ongoing on orbital timescales. Thus a kinetic description of the rings may be more appropriate than the fluid one. I will present Cassini Ultraviolet Spectrometer (UVIS) High Speed Photometer (HSP) occultations, Voyager 1 and 2 Imaging Science Subsystem (ISS), and high

  5. Ring wormholes via duality rotations

    Directory of Open Access Journals (Sweden)

    Gary W. Gibbons

    2016-09-01

    Full Text Available We apply duality rotations and complex transformations to the Schwarzschild metric to obtain wormhole geometries with two asymptotically flat regions connected by a throat. In the simplest case these are the well-known wormholes supported by phantom scalar field. Further duality rotations remove the scalar field to yield less well known vacuum metrics of the oblate Zipoy–Voorhees–Weyl class, which describe ring wormholes. The ring encircles the wormhole throat and can have any radius, whereas its tension is always negative and should be less than −c4/4G. If the tension reaches the maximal value, the geometry becomes exactly flat, but the topology remains non-trivial and corresponds to two copies of Minkowski space glued together along the disk encircled by the ring. The geodesics are straight lines, and those which traverse the ring get to the other universe. The ring therefore literally produces a hole in space. Such wormholes could perhaps be created by negative energies concentrated in toroidal volumes, for example by vacuum fluctuations.

  6. Dream of Isochronous Ring Again

    CERN Document Server

    Hama, H

    2005-01-01

    More than 20 years ago, D.A.G. Deacon proposed an isochronous storage ring for FEL to avoid bunch heating and decreasing instantaneous gain [1]. Some of low momentum compaction (alpha) operations have been carried out, and recently coherent infrared radiation are observed on a 3rd generation light source. Because the 3rd generation rings are optimized to obtain very low emittance beam, the dispersion function in the arc sections are much reduced by introducing large bending radius, so that those are very big machines. Meanwhile N.A. Vinokurov et al. recently proposed a ring type SASE FEL based on a complete isochronous bending transport [2]. At least, experimental and theoretical study of the isochronous ring so far suggests nonlinear effects resulted from higher order dispersion and chromaticity declines the "complete" isochronous system. On the other hand, in a wavelength region of THz, tolerance of the path length along a turn of the ring seems to be within our reach. A concept to preserve of a form factor...

  7. Burnside Rings of Fusion Systems

    DEFF Research Database (Denmark)

    Reeh, Sune Precht

    of the characteristic idempotent of F { the unique idempotent in the p-local double Burnside ring of S satisfying properties of Linckelmann and Webb. We describe this idempotent both in terms of fixed points and as a linear combination of transitive bisets. Additionally, using fixed points we determine the map......In this thesis we study the interactions between saturated fusion systems and group actions of the underlying p-groups. For a saturated fusion system F on a finite p-group S we construct the Burnside ring of F in terms of the finite S-sets whose actions respect the structure of the fusion system......, and we produce a basis for the Burnside ring that shares properties with the transitive sets for a finite group. We construct a transfer map from the p-local Burnside ring of the underlying p-group S to the p-local Burnside ring of F. Using such transfer maps, we give a new explicit construction...

  8. Ring polymers in confined geometries

    CERN Document Server

    Usatenko, Z; Kuterba, P

    2016-01-01

    The investigation of a dilute solution of phantom ideal ring polymers and ring polymers with excluded volume interactions (EVI) in a good solvent confined in a slit geometry of two parallel repulsive walls and in a solution of colloidal particles of big size were performed. Taking into account the correspondence between the field theoretical $\\phi^4$ $O(n)$-vector model in the limit $n\\to 0$ and the behavior of long-flexible polymer chains in a good solvent the correspondent depletion interaction potentials, depletion forces and the forces which exert phantom ideal ring and ring polymer chains with EVI on the walls were obtained in the framework of the massive field theory approach at fixed space dimensions d=3 up to one-loop order. Additionally, the investigation of a dilute solution of phantom ideal ring polymers in a slit geometry of two inert walls and mixed walls with one repulsive and other one inert wall were performed and correspondent depletion interaction potentials and the depletion forces were cal...

  9. Ring wormholes via duality rotations

    CERN Document Server

    Gibbons, Gary W

    2016-01-01

    We apply duality rotations and complex transformations to the Schwarzschild metric to obtain wormhole geometries with two asymptotically flat regions connected by a throat. In the simplest case these are the well-known wormholes supported by phantom scalar field. Further duality rotations remove the scalar field to yield less well known vacuum metrics of the oblate Zipoy-Voorhees-Weyl class, which describe ring wormholes. The ring encircles the wormhole throat and can have any radius, whereas its tension is always negative and should be less than $-c^4/4G$. If the tension reaches the maximal value, the geometry becomes exactly flat, but the topology remains non-trivial and corresponds to two copies of Minkowski space glued together along the disk encircled by the ring. The geodesics are straight lines, and those which traverse the ring get to the other universe. The ring therefore literally produces a whole in space. Such wormholes could perhaps be created by negative energies concentrated in toroidal volumes...

  10. CYCLIC CODES OVER FORMAL POWER SERIES RINGS

    Institute of Scientific and Technical Information of China (English)

    Dougherty Steven T.; Liu Hongwei

    2011-01-01

    In this article, cyclic codes and negacyclic codes over formal power series rings are studied. The structure of cyclic codes over this class of rings is given, and the relationship between these codes and cyclic codes over finite chain rings is obtained. Using an isomorphism between cyclic and negacyclic codes over formal power series rings, the structure of negacyclic codes over the formal power series rings is obtained.

  11. Trends In Satellite Communication

    Science.gov (United States)

    Poley, William A.; Stevens, Grady H.; Stevenson, Steven M.; Lekan, Jack; Arth, Clifford H.; Hollansworth, James E.; Miller, Edward F.

    1988-01-01

    Report assesses trends in satellite communication from present to year 2010. Examines restrictions imposed by limited spectrum resource and technology needs created by trends. Personal communications, orbiting switchboards, and videophones foreseen.

  12. Domestic Communication Satellites

    Science.gov (United States)

    Horowitz, Andrew

    1974-01-01

    A discussion of the Federal Communications Commission's new policy on domestic satellites in light of our 1) military and economic history; 2) corporate interests; 3) citizen surveillance; and 4) media control. (HB)

  13. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2013-01-01

    Top space experts from around the world have collaborated to produce this comprehensive, authoritative, and clearly illustrated reference guide to the fast growing, multi-billion dollar field of satellite applications and space communications. This handbook, done under the auspices of the International Space University based in France, addresses not only system technologies but also examines market dynamics, technical standards and regulatory constraints. The handbook is a completely multi-disciplinary reference book that covers, in an in-depth fashion, the fields of satellite telecommunications, Earth observation, remote sensing, satellite navigation, geographical information systems, and geosynchronous meteorological systems. It covers current practices and designs as well as advanced concepts and future systems. It provides a comparative analysis of the common technologies and design elements for satellite application bus structures, thermal controls, power systems, stabilization techniques, telemetry, com...

  14. Biological satellite Kosmos-936

    Science.gov (United States)

    Vedeshin, L. A.

    1978-01-01

    A description is given of physiological experiments performed on the biological satellite Kosmos-936. Other experiments to determine the electrostatic and dielectric responses to the effects of cosmic radiation are discussed.

  15. Small Satellite Transporter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary objective is to determine whether this small satellite transporter is capable of transporting at least four 6U CubeSats is possible for a given set of...

  16. Measurement of Satellite Bunches at the LHC

    CERN Document Server

    Jeff, A; Boccardi, A; Bozyigit, S; Bravin, E; Lefevre, T; Rabiller, A; Roncarolo, F; Welsch, C P; Fisher, A S

    2012-01-01

    The RF gymnastics involved in the delivery of proton and lead ion bunches to the LHC can result in satellite bunches of varying intensity occupying the nominally empty RF buckets. Quantification of these satellites is crucial for bunch-by-bunch luminosity normalization as well as for machine protection. We present an overview of the longitudinal density monitor (LDM) which is the principal instrument for the measurement of satellite bunches in the LHC. The LDM uses single photon counting of synchrotron light. The very high energies reached in the LHC, combined with a dedicated undulator for diagnostics, allow synchrotron light measurements to be made with both protons and heavy ions. The arrival times of photons are collected over a few million turns, with the resulting histogram corrected for the effects of the detector’s deadtime and afterpulsing in order to reconstruct the longitudinal profile of the entire LHC ring. The LDM has achieved a dynamic range in excess of 105 and a time resolution of 90 ps. Ex...

  17. Damping of Resonantly Forced Density Waves in Dense Planetary Rings

    Science.gov (United States)

    Lehmann, Marius; Schmidt, Jürgen; Salo, Heikki

    2016-10-01

    We address the stability of resonantly forced density waves in dense planetary rings.Already by Goldreich and Tremaine (1978) it has been argued that density waves might be unstable, depending on the relationship between the ring's viscosity and the surface mass density. In the recent paper (Schmidt et al. 2016) we have pointed out that when - within a fluid description of the ring dynamics - the criterion for viscous overstability is satisfied, forced spiral density waves become unstable as well. In this case, linear theory fails to describe the damping.We apply the multiple scale formalism to derive a weakly nonlinear damping relation from a hydrodynamical model.This relation describes the resonant excitation and nonlinear viscous damping of spiral density waves in a vertically integrated fluid disk with density dependent transport coefficients. The model consistently predicts linear instability of density waves in a ring region where the conditions for viscous overstability are met. In this case, sufficiently far away from the Lindblad resonance, the surface mass density perturbation is predicted to saturate to a constant value due to nonlinear viscous damping. In general the model wave damping lengths depend on a set of input parameters, such as the distance to the threshold for viscous overstability and the ground state surface mass density.Our new model compares reasonably well with the streamline model for nonlinear density waves of Borderies et al. 1986.Deviations become substantial in the highly nonlinear regime, corresponding to strong satellite forcing.Nevertheless, we generally observe good or at least qualitative agreement between the wave amplitude profiles of both models. The streamline approach is superior at matching the total wave profile of waves observed in Saturn's rings, while our new damping relation is a comparably handy tool to gain insight in the evolution of the wave amplitude with distance from resonance, and the different regimes of

  18. DFH-3 Satellite Platform

    Institute of Scientific and Technical Information of China (English)

    RenShufang

    2005-01-01

    The DFH-3 satellite platform is designed and developed by China Academy of Space Technology (CAST). It is a medium capability communications satellite platform. The platform adopts threeaxis attitude stabilization control system, having solar array output power of 1.7kW by the end of its design lifetime of 8 years. Its mass is 2100kg with payload capacity of 220kg.

  19. The Archimedes satellite system

    Science.gov (United States)

    Taylor, Stuart C.; Shurvinton, William D.

    1992-03-01

    Archimedes is a satellite system conceived by the European Space Agency (ESA) to effectively serve the European market for Mobile Radio Services (MRS). This paper describes the requirements and technical design of the Archimedes satellite system. The underlying assumptions and trade-offs behind the design are detailed and the design is compared and contrasted against alternative design solutions, both technically and economically. A path forward for the development of the system is indicated.

  20. ASTRID II satellit projekt

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Primdahl, Fritz

    1997-01-01

    The report describes the instruments developed for the Swedish micro satellite "ASTRID II". Specifications of the two instruments realized under this contract, a Stellar Compass and a CSC magnetometer are given follwed by a description of the project status and plan.......The report describes the instruments developed for the Swedish micro satellite "ASTRID II". Specifications of the two instruments realized under this contract, a Stellar Compass and a CSC magnetometer are given follwed by a description of the project status and plan....

  1. Cities as development drivers

    DEFF Research Database (Denmark)

    Johnson, Bjørn; Poulsen, Tjalfe; Hansen, Jens Aage

    2011-01-01

    for innovative problem solving and potential spill-over effects, which may stimulate further economic growth and development. This paper discusses how waste problems of cities can be transformed to become part of new, more sustainable solutions. Two cases are explored: Aalborg in Denmark and Malmö in Sweden....... It is shown that the cities have the potential to significantly contribute to a more sustainable development through increased material recycling and energy recovery. Waste prevention may increase this potential. For example, instead of constituting 3% of the total greenhouse gas emission problem, it seems......There is a strong connection between economic growth and development of cities. Economic growth tends to stimulate city growth, and city economies have often shaped innovative environments that in turn support economic growth. Simultaneously, social and environmental problems related to city growth...

  2. Traversable wormholes the Roman ring

    CERN Document Server

    Visser, M

    1997-01-01

    In this brief report I introduce a yet another class of geometries for which semi-classical chronology protection theorems are of dubious physical reliability. I consider a ``Roman ring'' of traversable wormholes, wherein a number of wormholes are arranged in a ring in such a manner that no subset of wormholes is near to chronology violation, though the combined system can be arbitrarily close to chronology violation. I show that (with enough wormholes in the ring) the gravitational vacuum polarization (the expectation value of the quantum stress-energy tensor) can be made arbitrarily small. In particular the back-reaction can be kept arbitrarily small all the way to the ``reliability horizon''---so that semi-classical quantum gravity becomes unreliable before the gravitational back reaction becomes large.

  3. Evaluation of Congestion Relief Proposals in a Capital City

    Directory of Open Access Journals (Sweden)

    Sudhir C. Fowdur

    2012-01-01

    Full Text Available This paper aims at analyzing three different solutions suggested for traffic congestion relief in Port Louis, the busiest city of Mauritius. It evaluates the impact of the three alternatives which are the use of Light Rail Transit (LRT as an alternative mode of transport, the construction of a Ring road around Port Louis, and the upgrading of the current bus network into a Bus Rapid Transit (BRT system. The impact of these three solutions has been evaluated by performing Traffic Cellular Automata (TCA simulations. Our studies reveal that the Ring road will lead to more congestion while introducing the LRT or upgrading the current bus network will reduce congestion significantly.

  4. Tree rings and radiocarbon calibration

    Energy Technology Data Exchange (ETDEWEB)

    Barbetti, M. [University of Sydney, Sydney, NSW (Australia). NWG Macintosh Centre for Quaternary Dating

    1999-11-01

    Only a few kinds of trees in Australia and Southeast Asia are known to have growth rings that are both distinct and annual. Those that do are therefore extremely important to climatic and isotope studies. In western Tasmania, extensive work with Huon pine (Lagarostrobos franklinii) has shown that many living trees are more than 1,000 years old, and that their ring widths are sensitive to temperature, rainfall and cloud cover (Buckley et al. 1997). At the Stanley River there is a forest of living (and recently felled) trees which we have sampled and measured. There are also thousands of subfossil Huon pine logs, buried at depths less than 5 metres in an area of floodplain extending over a distance of more than a kilometre with a width of tens of metres. Some of these logs have been buried for 50,000 years or more, but most of them belong to the period between 15,000 years and the present. In previous expeditions in the 1980s and 1990s, we excavated and sampled about 350 logs (Barbetti et al. 1995; Nanson et al. 1995). By measuring the ring-width patterns, and matching them between logs and living trees, we have constructed a tree-ring dated chronology from 571 BC to AD 1992. We have also built a 4254-ring floating chronology (placed by radiocarbon at ca. 3580 to 7830 years ago), and an earlier 1268-ring chronology (ca. 7,580 to 8,850 years ago). There are many individuals, or pairs of logs which match and together span several centuries, at 9,000 years ago and beyond 15 refs., 1 tab., 1 fig.

  5. CHINA LAUNCHES NEW SCIENTIFIC SATELLITE

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    China on Sept. 27, 2004 launched a scientific satellite atop a Long March 2D carrier rocket from Jiuquan Satellite Launch Center in Gansu province. 10 minutes after the launch, the satellite entered a preset orbit and is running sound at the orbit. It is the 20th recoverable satellite for scientific and technological

  6. On Simple-Injective Rings

    Institute of Scientific and Technical Information of China (English)

    W.K. Nicholson; Jae Keol Park; M.F. Yousif

    2002-01-01

    A ring R is called right simple-injective if every R-linear map from a right ideal of R to R with simple image can be extended to R. It is shown that a right simple-injective ring R is quasi-Frobenius if R is right Goldie with essential right socle, or R is left perfect and the right annihilator of k ∈ R is finitely generated whenever kR or Rk is simple. This extends a result of Bjork.

  7. On Ideals of Regular Rings

    Institute of Scientific and Technical Information of China (English)

    CHEN Huan Yin; LI Fu An

    2002-01-01

    In this paper, we investigate ideals of regular rings and give several characterizations for an ideal to satisfy the comparability. In addition, it is shown that, if Ⅰ is a minimal two-sided ideal of a regular ring R, then Ⅰ satisfies the comparability if and only if Ⅰ is separative. Furthermore, we prove that, for ideals with stable range one, Roth's problem has an affirmative solution. These extend the corresponding results on unit-regularity and one-sided unit-regularity.

  8. Nanoscale nonlinear PANDA ring resonator

    CERN Document Server

    Yupapin, Preecha

    2012-01-01

    Microring/nanoring resonator is an interesting device that has been widely studied and investigated by researchers from a variety of specializations. This book begins with the basic background of linear and nonlinear ring resonators. A novel design of nano device known as a PANDA ring resonator is proposed. The use of the device in the form of a PANDA in applications such as nanoelectronics, measurement, communication, sensors, optical and quantum computing, drug delivery, hybrid transistor and a new concept of electron-hole pair is discussed in detail.

  9. Laparoscopic appendicectomy using endo-ring applicator and fallope rings

    Directory of Open Access Journals (Sweden)

    Ali Iyoob

    2009-01-01

    Full Text Available Background/Aim: Wider adoption of laparoscopic appendicectomy (LA is limited by problems in securing the appendiceal base as well as the cost and the duration compared with the open procedure. The objective of this study was to assess the feasibility and efficacy of a new method for securing the appendiceal base in LA, so as to make the entire procedure simpler and cheaper, and hence, more popular. Methods: Twenty-five patients who were candidates for appendicectomy (emergency as well as elective and willing for the laparoscopic procedure were selected for this study. Ports used were 10 mm at the umbilicus, 5 mm at the lower right iliac fossa, and 10 mm at the left iliac fossa. Extremely friable, ruptured, or turgid organs of diameters larger than 8 mm were excluded from the study. The mesoappendix was divided close to the appendix by diathermy. Fallope rings were applied to the appendiceal base using a special ring applicator, and the appendix was divided and extracted through the lumen of the applicator. Results: The procedure was successful in 23 (92% cases, and the mean duration of the procedure was 20 minutes (15-32 minutes. There were no procedural complications seen during a median follow-up of two weeks. The equipment and rings were cheaper when compared with that of the standard methods of securing the base of the appendix. Conclusion: LA using fallope rings is a safe, simple, easy-to-learn, and economically viable method.

  10. ring i Praksis: Praksis i Læring

    DEFF Research Database (Denmark)

    Kjær, Malene

    2015-01-01

    I denne artiklen er empirien hentet fra et dansk sykehus der en sykepleiestudent skal gis tilgang til en bestemt fagkultur ved hjelp av den erfarne sykepleierens multimodale opplæringsform. I analysen vises, at ord, blikk, positur, berøring – alt inngår i en følsom samhandlingssituasjon der det o...

  11. EU Smart City Governance

    Directory of Open Access Journals (Sweden)

    Carmela Gargiulo

    2013-11-01

    Full Text Available In recent years European Commission has developed a set of documents for Members States tracing, directly or indirectly, recommendations for the transformation of the European city. The paper wants to outline which future EU draws for the city, through an integrated and contextual reading of addresses and strategies contained in the last documents, a future often suggested as Smart City. Although the three main documents (Cohesion Policy 2014-2020 of European Community, Digital Agenda for Europe and European Urban Agenda face the issue of the future development of European cities from different points of view, which are respectively cohesion social, ICT and urban dimension, each of them pays particular attention to urban and territorial dimension, identified by the name of Smart City. In other words, the paper aims at drawing the scenario of evolution of Smart Cities that can be delineated through the contextual reading of the three documents. To this end, the paper is divided into three parts: the first part briefly describes the general contents of the three European economic plan tools; the second part illustrates the scenarios for the future of the European city contained in each document; the third part seeks to trace the evolution of the Smart Cities issue developed by the set of the three instruments, in order to provide the framework of European Community for the near future of our cities

  12. Different Creative Cities

    DEFF Research Database (Denmark)

    Lorenzen, Mark; Vaarst Andersen, Kristina

    2012-01-01

    and exhibits a tendency of congregating in major cities with diverse service and cultural offers and tolerance to non-mainstream lifestyles. However, we find that a range of smaller Danish cities also attract the creative class. Second, we undertake qualitative interviews that facilitate theory building. We...... suggest that many creatives are attracted by the smaller cities' cost advantages, specialized job offers, attractive work/life balances, and authenticity and sense of community. The article synthesizes its results into four stylized types of creative cities, and concludes by discussing the policy...

  13. Suburbs and Cities

    OpenAIRE

    William N. Goetzmann; Matthew I. Spiegel; Susan M. Wachter

    1996-01-01

    This paper addresses the issue of how closely the fortunes of suburbs are tied to the fortunes of the central city. We use similarities in residential housing price dynamics as a measure of how closely the economies of cities and suburbs are related. We develop housing price indices for most of the zip codes in California, and use these in a clustering procedure to see whether cities and suburbs naturally aggregate together, or whether they move separately. We find that central cities tend to...

  14. Governing the City

    DEFF Research Database (Denmark)

    Kornberger, Martin

    2012-01-01

    cities. This theoretical curiosity is reflected in the rising interest in urban strategy from practice. For instance, the World Bank regularly organizes an Urban Strategy Speaker Series, while the powerful network CEOs for Cities lobbies for a strategic approach to urban development. Critical scholars...... such as Zukin diagnose not a shift in but a shift to strategic thinking in the contemporary city. This article poses the question: what makes strategy such an attractive ‘thought style’ in relation to imagining and managing cities? How can we understand the practice of urban strategy? And what are its intended...

  15. On the confinement of Neptune's ring arcs by co-orbital moonlets

    Science.gov (United States)

    Sicardy, B.; Renner, S.

    2003-05-01

    Recent HST and Earth-based observations (Dumas, C. et al., Nature, 400, 733, 1999; Sicardy, B. et al., Nature 400, 731, 1999) indicate that Neptune's ring arcs are near but not within the 42:43 corotation resonance with Galatea, thought to be responsible for the azimuthal confinement of the arc system (Porco, C.C., Science, 253, 995, 1991). Consequently a new resonance structure based only on Galatea's eccentricity has been proposed to explain the arcs' stability : if the arcs have a sufficient fraction of the mass of Galatea, then the 42:43 eccentric corotation resonance with this moon, located in the massless case 3 km inside the arcs' orbit, can match the current arcs' semimajor axis (Namouni, F. and Porco, C.C., Nature, 417, 47, 2002). The ring mass they determined corresponds to a parent ˜ 10-km-radius satellite with a density similar to that of Galatea. Because Voyager data exclude undetected satellites of radius larger than ˜ 6 km, the mass required for the arcs' confinement is probably not contained in a single body. Here we present an alternative solution fully compatible with the latest observations in which small co-orbital satellites confine the observed dusty ring material. These hypothetical co-orbital bodies would be in a stable stationary configuration. There is an infinity of solutions for such stationary configurations, depending on the satellite masses (Renner, S. and Sicardy, B., CeMDA, submitted), which reproduce all the features of the arc system. We have tested numerically the stability of the system over centuries, in a purely gravitational case but also under the effects of collisions and PR drag. We show how Adam's ring material can evolve towards stable stationary configurations of several co-orbital satellites through the Galatea's secular torques.

  16. Satellite Communications for ATM

    Science.gov (United States)

    Shamma, Mohammed A.

    2003-01-01

    This presentation is an overview on Satellite Communication for the Aeronautical Telecommunication Management (ATM) research. Satellite Communications are being considered by the FAA and NASA as a possible alternative to the present and future ground systems supporting Air Traffic Communications. The international Civil Aviation Organization (ICAO) have in place Standards and Recommended Practices (SARPS) for the Aeronautical Mobile Satellite Services (AMSS) which is mainly derived from the pre-existing Inmarsat service that has been in service since the 1980s. The Working Group A of the Aeronautical Mobile Communication Panel of ICAO has also been investigating SARPS for what is called the Next Generation Satellite Service (NGSS) which conforms less to the Inmarsat based architecture and explores wider options in terms of satellite architectures. Several designs are being proposed by Firms such as Boeing, ESA, NASA that are geared toward full or secondary usage of satellite communications for ATM. Satellite communications for ATM can serve several purposes ranging from primary usage where ground services would play a minimal backup role, to an integrated solution where it will be used to cover services, or areas that are less likely to be supported by the proposed and existing ground infrastructure. Such Integrated roles can include usage of satellite communications for oceanic and remote land areas for example. It also can include relieving the capacity of the ground network by providing broadcast based services of Traffic Information Services messages (TIS-B), or Flight Information Services (FIS-B) which can take a significant portion of the ground system capacity. Additionally, satellite communication can play a backup role to support any needs for ground replacement, or additional needed capacity even after the new digital systems are in place. The additional bandwidth that can be provided via satellite communications can also open the door for many new

  17. Extracting information on urban impervious surface from GF-1 data in Tianjin City of China

    Science.gov (United States)

    Li, Bin; Meng, Qingyan; Wu, Jun; Gu, Xingfa

    2015-09-01

    The urban impervious surface, an important part in the city system, has a great influence on theecologicalenvironment in urban areas. The coverage of it is an important indicator for the evaluation ofurbanization. TheRemotesensing data has prominent features such as information-rich and accurate and it can provide data basis for large area extraction of impervious surface. GF-1 satellite is the first satellite of high-resolution earth observation system in China. With the homemade GF-1 satellite remote sensing image date as a resolution, this research, by the combination of V-I-S model and linear spectral mixture model, has first made estimation on the impervious surface of Tianjin City and then employed the remote sensingimage date with high resolution to test the precision of the estimated results. The results not only show that this method will make high precision available, but also reveal that Tianjin City has a wide coverage of impervious surface in general level, especially a high coverage rate both in the center and the coastal areas. The average coverage of impervious surface of the Tianjin city is very high and the coverage of impervious surface in the center and the coastal areas of Tianjin city reach seventy percent.City managers can use these data to guide city management and city planning.

  18. A Experimental Study of Viscous Vortex Rings.

    Science.gov (United States)

    Dziedzic, Mauricio

    Motivated by the role played by vortex rings in the process of turbulent mixing, the work is focused on the problem of stability and viscous decay of a single vortex ring. A new classification is proposed for vortex rings which is based on extensive hot-wire measurements of velocity in the ring core and wake and flow visualization. Vortex rings can be classified as laminar, wavy, turbulence-producing, and turbulent. Prediction of vortex ring type is shown to be possible based on the vortex ring Reynolds number. Linear growth rates of ring diameter with time are observed for all types of vortex rings, with different growth rates occurring for laminar and turbulent vortex rings. Data on the viscous decay of vortex rings are used to provide experimental confirmation of the accuracy of Saffman's equation for the velocity of propagation of a vortex ring. Experimental data indicate that instability of the vortex ring strongly depends on the mode of generation and can be delayed by properly adjusting the generation parameters. A systematic review of the literature on vortex-ring interactions is presented in the form of an appendix, which helps identify areas in which further research may be fruitful.

  19. Experimental Satellite 2 Successfully Launched

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    Small satellite Experimental Satellite 2 (SY-2) was launched by LM-2C launch vehicle from Xichang Satellite Launch Center on Nov. 18, 2004. Later the satellite entered the preset sun-synchronous orbit, which is 700 kilometers above the earth. The launch was the eighthmission this year by China Aerospace Science and Technology Corporation(CASC), which aims to test the technology of the satellite, conduct survey and monitoring of the land and resources and geographical environment on a trial basis.

  20. China's Meteorological Satellite Application System

    Institute of Scientific and Technical Information of China (English)

    Zhang Jiashen

    2008-01-01

    @@ China's meteorological satellite program consists of five systems,namely the satellite system,the launch vehicle system,the launch center system,TT&C and the ground application system.The satellite system consists of FengYun (FY) polar orbiting series and FY geostationary series,which are launched by LM launch vehicles from Taiyan Satellite Launch Center (TSLC) and Xichang Satellite Launch Center (XSLC) respectively.

  1. Astrometric positioning and orbit determination of geostationary satellites

    Science.gov (United States)

    Montojo, F. J.; López Moratalla, T.; Abad, C.

    2011-03-01

    In the project titled “Astrometric Positioning of Geostationary Satellite” (PASAGE), carried out by the Real Instituto y Observatorio de la Armada (ROA), optical observation techniques were developed to allow satellites to be located in the geostationary ring with angular accuracies of up to a few tenths of an arcsec. These techniques do not necessarily require the use of large telescopes or especially dark areas, and furthermore, because optical observation is a passive method, they could be directly applicable to the detection and monitoring of passive objects such as space debris in the geostationary ring.By using single-station angular observations, geostationary satellite orbits with positional uncertainties below 350 m (2 sigma) were reconstructed using the Orbit Determination Tool Kit software, by Analytical Graphics, Inc. This software is used in collaboration with the Spanish Instituto Nacional de Técnica Aeroespacial.Orbit determination can be improved by taking into consideration the data from other stations, such as angular observations alone or together with ranging measurements to the satellite. Tests were carried out combining angular observations with the ranging measurements obtained from the Two-Way Satellite Time and Frequency Transfer technique that is used by ROA’s Time Section to carry out time transfer with other laboratories. Results show a reduction of the 2 sigma uncertainty to less than 100 m.

  2. SELF-DUAL PERMUTATION CODES OVER FORMAL POWER SERIES RINGS AND FINITE PRINCIPAL IDEAL RINGS

    Institute of Scientific and Technical Information of China (English)

    张光辉; 刘宏伟

    2013-01-01

    In this paper, we study self-dual permutation codes over formal power series rings and finite principal ideal rings. We first give some results on the torsion codes associated with the linear codes over formal power series rings. These results allow for obtaining some conditions for non-existence of self-dual permutation codes over formal power series rings. Finally, we describe self-dual permutation codes over finite principal ideal rings by examining permutation codes over their component chain rings.

  3. The City at Stake:

    Directory of Open Access Journals (Sweden)

    Sophie Esmann Andersen

    2009-12-01

    Full Text Available Studies of the city have been addressed from many different approaches such as law, political science, art history and public administration, in which the eco-nomic, political and legal status of the city have played a major role. However, a new agenda for conceptualizing the city has emerged, in which the city assumes new roles. By using stakeholder theory as a framework for conceptualizing the city, we argue that the city assumes a political-economic agenda-setting role as well as providing a stage for identity constructions and relational performances for consumers, organizations, the media, politicians and other stakeholders. Stakeholder theory allows us to conceptualize the city as being constituted by stakes and relationships between stakeholders which are approached from three analytical positions (modern, postmodern and hypermodern, respectively, thereby allowing us to grasp different stakes and types of relationships, ranging from functional and contractual relationships to individualized and emotionally driven or more non-committal and fluid forms of relationships. In order to support and illustrate the analytical potentials of our framework for conceptualizing urban living, we introduce a project which aims to turn the city of Aarhus into a CO2-neutral city by the year 2030, entitled Aarhus CO2030. We conclude that applying stakeholder theory to a hyper-complex organization such as a city opens up for a reconceptualization of the city as a web of stakes and stakeholder relations. Stakeholder theory contributes to a nuanced and elaborate understanding of the urban complexity and web of both enforced and voluntary relationships as well as the different types of relationships that characterize urban life.

  4. Ringing phenomenon in silica microspheres

    Institute of Scientific and Technical Information of China (English)

    Chunhua Dong; Changling Zou; Jinming Cui; Yong Yang; Zhengfu Han; Guangcan Guo

    2009-01-01

    Whispering gallery modes in silica microspheres are excited by a tunable continuous-wave laser through the fiber taper. Ringing phenomenon can be observed with high frequency sweeping speed. The thermal nonlinearity in the microsphere can enhance this phenomenon. Our measurement results agree very well with the theoretical predictions by the dynamic equation.

  5. Characteristic of Rings. Prime Fields

    Directory of Open Access Journals (Sweden)

    Schwarzweller Christoph

    2015-12-01

    Full Text Available The notion of the characteristic of rings and its basic properties are formalized [14], [39], [20]. Classification of prime fields in terms of isomorphisms with appropriate fields (ℚ or ℤ/p are presented. To facilitate reasonings within the field of rational numbers, values of numerators and denominators of basic operations over rationals are computed.

  6. The Lord of the Rings

    Institute of Scientific and Technical Information of China (English)

    潘金梅

    2002-01-01

    Peter Jackson's first film in The Lord of the Rings trilogy (三步曲) has just grabbed (夺得) four Oscars-awards for the best make-up, best cinematography (摄影), best visual effects and best original score.Chinese audience had a chance to watch the fihn from late April.

  7. Fusion rings and fusion ideals

    DEFF Research Database (Denmark)

    Andersen, Troels Bak

    by the so-called fusion ideals. The fusion rings of Wess-Zumino-Witten models have been widely studied and are well understood in terms of precise combinatorial descriptions and explicit generating sets of the fusion ideals. They also appear in another, more general, setting via tilting modules for quantum...

  8. E-læring

    DEFF Research Database (Denmark)

    Heilesen, Simon

    2001-01-01

    E-læring er et modeord og et mantra. Undervisning bliver ikke automatisk bedre af, at der sættes et ”e-” foran. Forbedring og fornyelse af undervisningen er betinget af, at vi forstår computermediets muligheder og skaber forandring ved at tilpasse det til de undervisningsformer, vi ønsker....

  9. Exercises in modules and rings

    CERN Document Server

    Lam, TY

    2009-01-01

    This volume offers a compendium of exercises of varying degree of difficulty in the theory of modules and rings. All exercises are solved in full detail. Each section begins with an introduction giving the general background and the theoretical basis for the problems that follow.

  10. Livslang læring

    DEFF Research Database (Denmark)

    Larson, Anne

    2016-01-01

    Pædagogisk sociologi beskæftiger sig blandt andet med de politiske rammebetingelser for opdragelse, undervisning, socialisering og uddannelse. I dette kapitel præsenteres en komparativ undersøgelse af EU’s politik med hensyn til livslang læring på den ene side, og den danske politik og lovgivning...

  11. Counting problems for number rings

    NARCIS (Netherlands)

    Brakenhoff, Johannes Franciscus

    2009-01-01

    In this thesis we look at three counting problems connected to orders in number fields. First we study the probability that for a random polynomial f in Z[X] the ring Z[X]/f is the maximal order in Q[X]/f. Connected to this is the probability that a random polynomial has a squarefree discriminant. T

  12. Near rings, fuzzy ideals, and graph theory

    CERN Document Server

    Satyanarayana, Bhavanari

    2013-01-01

    Near Rings, Fuzzy Ideals, and Graph Theory explores the relationship between near rings and fuzzy sets and between near rings and graph theory. It covers topics from recent literature along with several characterizations. After introducing all of the necessary fundamentals of algebraic systems, the book presents the essentials of near rings theory, relevant examples, notations, and simple theorems. It then describes the prime ideal concept in near rings, takes a rigorous approach to the dimension theory of N-groups, gives some detailed proofs of matrix near rings, and discusses the gamma near

  13. Cascaded uncoupled dual-ring modulator

    CERN Document Server

    Gu, Tingyi; Wong, Chee Wei; Dong, Po

    2014-01-01

    We demonstrate that by coherent driving two uncoupled rings in same direction, the effective photon circulating time in the dual ring modulator is reduced, with increased modulation quality. The inter-ring detuning dependent photon dynamics, Q-factor, extinction ratio and optical modulation amplitude of two cascaded silicon ring resonators are studied and compared with that of a single ring modulator. Experimentally measured eye diagrams, together with coupled mode theory simulations, demonstrate the enhancement of dual ring configuration at 20 Gbps with a Q ~ 20,000.

  14. High-Speed Ring Bus

    Science.gov (United States)

    Wysocky, Terry; Kopf, Edward, Jr.; Katanyoutananti, Sunant; Steiner, Carl; Balian, Harry

    2010-01-01

    The high-speed ring bus at the Jet Propulsion Laboratory (JPL) allows for future growth trends in spacecraft seen with future scientific missions. This innovation constitutes an enhancement of the 1393 bus as documented in the Institute of Electrical and Electronics Engineers (IEEE) 1393-1999 standard for a spaceborne fiber-optic data bus. It allows for high-bandwidth and time synchronization of all nodes on the ring. The JPL ring bus allows for interconnection of active units with autonomous operation and increased fault handling at high bandwidths. It minimizes the flight software interface with an intelligent physical layer design that has few states to manage as well as simplified testability. The design will soon be documented in the AS-1393 standard (Serial Hi-Rel Ring Network for Aerospace Applications). The framework is designed for "Class A" spacecraft operation and provides redundant data paths. It is based on "fault containment regions" and "redundant functional regions (RFR)" and has a method for allocating cables that completely supports the redundancy in spacecraft design, allowing for a complete RFR to fail. This design reduces the mass of the bus by incorporating both the Control Unit and the Data Unit in the same hardware. The standard uses ATM (asynchronous transfer mode) packets, standardized by ITU-T, ANSI, ETSI, and the ATM Forum. The IEEE-1393 standard uses the UNI form of the packet and provides no protection for the data portion of the cell. The JPL design adds optional formatting to this data portion. This design extends fault protection beyond that of the interconnect. This includes adding protection to the data portion that is contained within the Bus Interface Units (BIUs) and by adding to the signal interface between the Data Host and the JPL 1393 Ring Bus. Data transfer on the ring bus does not involve a master or initiator. Following bus protocol, any BIU may transmit data on the ring whenever it has data received from its host. There

  15. The Orbits of Saturn's Small Satellites

    Science.gov (United States)

    Spitale, J. N.; Jacobson, R. A.; Porco, C. C.; Owen, W. M.; Charnoz, S.

    2005-05-01

    We report on the orbits of the small, inner Saturnian satellites, either recovered or newly-discovered in recent Cassini imaging observations (excluding Helene, Telesto and Calypso, which will be discussed by another group). Using combined Cassini and Voyager observations, the mean motions of Pan and Atlas have been refined by several orders of magnitude. The Atlas orbit is based on a numerical integration perturbed by all of the massive Saturnian satellites including Prometheus, Pandora, Janus, and Epimetheus. We find that the dominant perturber is Prometheus. Cassini, Voyager, HST, and Earth-based data have been used to refine the orbits of Janus, Epimetheus, Prometheus and Pandora. The orbits of the co-orbitals, Janus and Epimetheus, remain stable; their orbital swap does not occur until Februrary, 2006. The orbits of Prometheus and Pandora remain close to recent values (Jacobson and French 2004, Icarus, 172, 382). Six new objects have been discovered to date -- three (S/2004 S3, S4, S6) in close proximity to the F ring, two (S/2004 S1(Methone), S/2004 S2(Pallene)) between the orbits of Mimas and Enceladus, and one (S/2004 S5(Polydeuces)) co-orbital with Dione, trailing by ˜60 deg (Porco et al., Science 307, 25 Feb 2005). One of the F-ring objects -- S/2004 S3 -- was seen over a 118-day interval, but none of those objects, including S/2004 S3, were subsequently recovered in an F-ring movie acquired on 15 November 2004 (29 days after the last sighting of S/2004 S3) with an image scale of 4 km/pixel, in which all were expected to appear. Consequently, we are confident only that Methone, Pallene and Polydeuces are solid satellites; S/2004 S3, S4 and S6 may be transient clumps. Our orbital fits, both precessing ellipse models and orbital integrations, suggest that Pallene is the same object as S/1981 S14, imaged by Voyager 2 on 23 August 1981, contrary to our initial reports (IAU circular 8389). The orbital inclination and eccentricity of Methone are considerably

  16. A liveable city:

    DEFF Research Database (Denmark)

    Sommerlund, Julie

    2014-01-01

    is increas- ingly based in and on cities rather than nations, and cities compete for businesses, branding, tourists and talent. In the western world, urbanisation has happened simultane- ously to de-industrialisation, which has opened industrial neighbourhoods and harbours for new uses – often focus- ing...

  17. Deer City Legend

    Institute of Scientific and Technical Information of China (English)

    LIUHUANZHI; LILIKUN

    2003-01-01

    MORE and more commodities,such as clothes,shoes,millinery,lighters and shavers,now bear the “Made in Wenzhou”mark.It woule appear that Wenzhou grooms the whole nation.Lucheng(deer city)District in central Wenzhou is the nucleus of the city's thriving light industry sector.

  18. Reflective cool cities

    NARCIS (Netherlands)

    Heidegger, V.

    2011-01-01

    This "designers' manual" is made during the TIDO-course AR0531 Smart & Bioclimatic Design. Our globe is heating, and cities are heating up much more. At the same time, cities are growing and green spaces are substituted by buildings and streets. These man-made surfaces are dark and tend to heat up

  19. Walkout in Crystal City

    Science.gov (United States)

    Barrios, Greg

    2009-01-01

    When students take action, they create change that extends far beyond the classroom. In this article, the author, who was a former teacher from Crystal City, Texas, remembers the student walkout that helped launch the Latino civil rights movement 40 years ago. The Crystal City student walkout remains a high point in the history of student activism…

  20. Preface (to Playable Cities)

    NARCIS (Netherlands)

    Unknown, [Unknown; Nijholt, A.; Nijholt, Antinus

    In this book, we address the issue of playfulness and playability in intelligent and smart cities. Playful technology can be introduced and authorized by city authorities. This can be compared and is similar to the introduction of smart technology in theme and recreational parks. However, smart

  1. City Improves State Enterprises

    Institute of Scientific and Technical Information of China (English)

    EnjoyceZhu

    2003-01-01

    As China's new leadership drafts measures to help ailing Stateowned enterprises(SOEs),Changchun,a strategic city in the Rust Belt,is reaping benefits unseen in more than a decade of SOE reform.Home to a large number of SOEs,Changchun has had its share of bureaucracy and stagnation.The city initiated a program called,“Saving SOEs

  2. CHONGQING, the Hot City

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ Chongqing is a well-known city with a history of more than 3,000 years. It is a famous historical and cultural city in China. Chongqing is the birthplace of the Bayu Culture. At present, Chongqing is a municipality directly under the Central Government with the largest area, the most administrative districts and the largest population.

  3. City profile: Paramaribo

    NARCIS (Netherlands)

    Verrest, H.J.L.M.

    2010-01-01

    Paramaribo, the largest and only significant urban area in Suriname, is a typical primate city. The majority of the countries’ population resides here and the majority of political, social and economic functions is clustered in the urban zone. In the course of the 20th century, the city changed dram

  4. Making the Experience City

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2009-01-01

    This paper describes the latest research into cultural planning and architectural branding in Denmark based on the ‘Experience City' research project located at Aalborg University. The paper explores the implication of the turn towards culture and experience in the contemporary Danish city. It thus...

  5. Futures of cities

    DEFF Research Database (Denmark)

    2008-01-01

    Bogen dokumenterer resultater fra den internationale kongres Futures of Cities arrangeret af IFHP International Federation of Housing and Planning, Realdania, Kunstakademiets Arkitektskole og City of Copenhagen. Kongressen blev afholdt i september 2007 i Øksnehallen og på Kunstakademiets Arkitekt...

  6. Seasonal activity budget of adult baltic ringed seals.

    Directory of Open Access Journals (Sweden)

    Tero Harkonen

    Full Text Available Although ringed seals are important components in oceanic and fresh water ecosystems at high latitudes, little is known about how they exploit these harsh environments. Seasonal activity and diving behaviour of 19 adult Baltic ringed seals were studied by satellite telemetry. We elaborated an activity budget for ten months of the year, extending over the period from moult to the breeding season. Seals from three main regions showed explicit site fidelity and the distributions of animals tagged from different areas did not overlap, suggesting separate stocks. Both the mean duration and the mean depth of dives peaked in June and July. Seals spent 70% (females to 85% (males of their time diving in June and July which decreased to 50% in late autumn. Less than one percent of dives exceeded 10 min in females, while 10% of male dives lasted longer than 10 min in June to September. Less than one percent of dives lasted for more than 25 min. Both females and males were most active during day time and hauled out predominantly during the night. Activity patterns during the summer are suggested to be correlated to energy accumulation and prey availability. The information on seasonal activity budget is crucial for developing population energetic models where interactions between ringed seals and other trophic levels can be evaluated.

  7. Formation of Janus and Epimetheus from Saturn's rings as coorbitals, thanks to Mimas' 2:3 inner Mean Motion Resonances

    Science.gov (United States)

    Aurélien, Crida; El Moutamid, Maryame

    2017-06-01

    Janus and Epimetheus orbit Saturn at 151461 km on average, on mutual horseshoe orbits with orbital separation 50 km, exchanging position every 4 years. This configuration is unique and intriguing : Lissauer et al. (1985) have shown that their orbital separation should converge to zero in about 20 Myrs only, and no satisfactory model for the origin of this co-orbital resonance exists yet. Charnoz et al. (2010) have shown that Janus and Epimetheus probably formed from the spreading of the rings beyond the Roche radius. Here, we study this phenomenon in the frame of the elliptical restricted 3-body problem, where ring particles are perturbed by the 2:3 mean motion resonances with the outer satellite Mimas.Two types of resonances play different roles. The Lindblad resonance (LR) confines the rings radially, and prevents their spreading (like the B-ring into the Cassini division). The Corotation resonance (CR) confines the rings azimuthally in two capture sites (akin Neptune's arcs). Because of Saturn's J_2, the CR is 130 km closer to Saturn than the LR. A few hundred million years ago, the 2:3 mean motion resonances with Mimas were just inside the Roche radius ; hence the rings could not spread and the two capture sites were full of ring material. When Mimas migrated outwards so that its 2:3 mean motion resonances receded past the Roche radius, the captured material agglomerated into two bodies of ~10^{15} kg on the exact same orbit. These bodies then migrated outwards together due to their interaction with the rings, in mutual horseshoe orbits. The rings then spawn new small satellites, eventually accreted by the proto-Janus and the proto-Epimetheus following the pyramidal regime of the ring spreading model (Crida & Charnoz 2012). The two bodies then grow in mass following a Fibonacci sequence, and this excites their orbital separation, leading to a configuration close to the present one.

  8. Planets and satellites: tectonic twins

    Science.gov (United States)

    Kochemasov, G. G.

    2015-10-01

    There are only three solid planet-satellite pairs in the Solar system: Earth -Moon, Mars -Phobos, Pluto - Charon. For the first two pairs tectonic analogies were shown and explained by moving them in one circumsolar orbit. As it is known from the wave planetology [3, 4, 6], "orbits make structures". For the third pair the same was stated as a prediction based on this fundamental rule. Global tectonic forms of wave origin appear in cosmic bodies because they move in keplerian orbits with periodically changing accelerations. Warping bodies waves have a stationary character and obeying wave harmonics lengths. Starting from the fundamental 2πR-long wave 1 making the ubiquitous tectonic dichotomy (two-face appearance) warping wave lengths descend along harmonics. Very prominent along with the wave 1 are waves 2 responsible for tectonic sectoring superimposed on the wave 1 segments. Practically all bodies have traces of shorter waves making numerous polygons (rings) often confused with impact craters. Earth and the Moon moving in one circumsolar orbit both are distorted by wave 1, wave 2 and wave 4 features aligned along extent tectonic lines [4, 5]. At Earth they are: Pacific Ocean (2πR-structure) and Indian Ocean (πR-structure) from both ends with Malay Archipelago (πR/4-structure) in the middle. At Moon they are: Procellarum Ocean (2πR) and SPA Basin (πR) from ends and Mare Orientale (πR/4) in the middle. A regular disposition is surprising. Both Oceans and Basin occur on opposite hemispheres, lying in the middle both ring structures occur in the boundary between two hemispheres and are of the same relative size. These triads stretch along lines parallel to the equator (Earth) and with the angle about 30 degrees to it (Moon) indicating at a different orientation of the rotation axes in the ancient time [2]. On the whole, one could speak about a "lunar mould" of Earth [5] (Fig. 1-3). Another tectonic twin is the pair Mars -Phobos. Both bodies sharing one

  9. Universities Scale Like Cities

    CERN Document Server

    van Raan, Anthony F J

    2012-01-01

    Recent studies of urban scaling show that important socioeconomic city characteristics such as wealth and innovation capacity exhibit a nonlinear, particularly a power law scaling with population size. These nonlinear effects are common to all cities, with similar power law exponents. These findings mean that the larger the city, the more disproportionally they are places of wealth and innovation. Local properties of cities cause a deviation from the expected behavior as predicted by the power law scaling. In this paper we demonstrate that universities show a similar behavior as cities in the distribution of the gross university income in terms of total number of citations over size in terms of total number of publications. Moreover, the power law exponents for university scaling are comparable to those for urban scaling. We find that deviations from the expected behavior can indeed be explained by specific local properties of universities, particularly the field-specific composition of a university, and its ...

  10. Great cities look small

    CERN Document Server

    Sim, Aaron; Barahona, Mauricio; Stumpf, Michael P H

    2015-01-01

    Great cities connect people; failed cities isolate people. Despite the fundamental importance of physical, face-to-face social-ties in the functioning of cities, these connectivity networks are not explicitly observed in their entirety. Attempts at estimating them often rely on unrealistic over-simplifications such as the assumption of spatial homogeneity. Here we propose a mathematical model of human interactions in terms of a local strategy of maximising the number of beneficial connections attainable under the constraint of limited individual travelling-time budgets. By incorporating census and openly-available online multi-modal transport data, we are able to characterise the connectivity of geometrically and topologically complex cities. Beyond providing a candidate measure of greatness, this model allows one to quantify and assess the impact of transport developments, population growth, and other infrastructure and demographic changes on a city. Supported by validations of GDP and HIV infection rates ac...

  11. Marriage and the City

    DEFF Research Database (Denmark)

    Gautier, Pieter; Svarer, Michael; Teulings, Coen

    Do people move to cities because of marriage market considerations? In cities singles can meet more potential partners than in rural areas. Singles are therefore prepared to pay a premium in terms of higher housing prices. Once married, the marriage market benefits disappear while the housing...... premium remains. We extend the model of Burdett and Coles (1997) with a distinction between efficient (cities) and less efficient (non-cities) search markets. One implication of the model is that singles are more likely to move from rural areas to cities while married couples are more likely to make...... the reverse movement. A second prediction of the model is that attractive singles benefit most from a dense market (i.e. from being choosy). Those predictions are tested with a unique Danish dataset....

  12. Marriage and the City

    DEFF Research Database (Denmark)

    Gautier, Pieter; Svarer, Michael; Teulings, Coen

    Do people move to cities because of marriage market considerations? In cities singles can meet more potential partners than in rural areas. Singles are therefore prepared to pay a premium in terms of higher housing prices. Once married, the marriage market benefits disappear while the housing...... premium remains. We extend the model of Burdett and Coles (1997) with a distinction between efficient (cities) and less efficient (non-cities) search markets. One implication of the model is that singles are more likely to move from rural areas to cities while married couples are more likely to make...... the reverse movement. A second prediction of the model is that attractive singles benefit most from a dense market (i.e. from being choosy). Those predictions are tested with a unique Danish dataset....

  13. The Flickering Global City

    Directory of Open Access Journals (Sweden)

    Eric Slater

    2015-08-01

    Full Text Available This article explores new dimensions of the global city in light of the correlation between hegemonic transition and the prominence of financial centers. It counterposes Braudel’s historical sequence of dominant cities to extant approaches in the literature, shifting the emphasis from a convergence of form and function to variations in history and structure. The marked increase of finance in the composition of London, New York and Tokyo has paralleled each city’s occupation of a distinct niche in world financial markets: London is the principal center of currency exchange, New York is the primary equities market, and Tokyo is the leader in international banking. This division expresses the progression of world-economies since the nineteenth century and unfolds in the context of the present hegemonic transition. By combining world-historical and city-centered approaches, the article seeks to reframe the global city and overcome the limits inherent in the paradigm of globalization.

  14. A liveable city:

    DEFF Research Database (Denmark)

    Sommerlund, Julie

    2014-01-01

    There are over 20 cities world-wide with a population of over 10 million people. We have entered ‘The Millennium of the City’. The growth of urban populations has been accompanied by profound changes of the cities’ economic and social profile and of the cities themselves. The world economy...... is increas- ingly based in and on cities rather than nations, and cities compete for businesses, branding, tourists and talent. In the western world, urbanisation has happened simultane- ously to de-industrialisation, which has opened industrial neighbourhoods and harbours for new uses – often focus- ing...... on experience. We will argue for a human turn in the research on liveabil- ity and urbanisation, and debates the concept of liveability. We will take Copenhagen as our main case and compare with other cities from around the world....

  15. Anaglyph, Salt Lake City, Utah

    Science.gov (United States)

    2002-01-01

    The 2002 Winter Olympics are hosted by Salt Lake City at several venues within the city, in nearby cities, and within the adjacent Wasatch Mountains. This anaglyph image provides a stereoscopic map view of north central Utah that includes all of these Olympic sites. In the south, next to Utah Lake, Provo hosts the ice hockey competition. In the north, northeast of the Great Salt Lake, Ogden hosts curling and the nearby Snowbasin ski area hosts the downhill events. In between, southeast of the Great Salt Lake, Salt Lake City hosts the Olympic Village and the various skating events. Further east, across the Wasatch Mountains, the Park City ski resort hosts the bobsled, ski jumping, and snowboarding events. The Winter Olympics are always hosted in mountainous terrain. This view shows the dramatic landscape that makes the Salt Lake City region a world-class center for winter sports.The stereoscopic effect of this anaglyph was created by first draping a Landsat satellite image over a Shuttle Radar Topography Mission digital elevation model and then generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed

  16. The Canarias Einstein Ring: a Newly Discovered Optical Einstein Ring

    CERN Document Server

    Bettinelli, Margherita; Aparicio, Antonio; Hidalgo, Sebastian L; Cassisi, Santi; Walker, Alistair R; Piotto, Giampaolo; Valdes, Frank

    2016-01-01

    We report the discovery of an optical Einstein Ring in the Sculptor constellation, IAC J010127-334319, in the vicinity of the Sculptor Dwarf Spheroidal Galaxy. It is an almost complete ring ($\\sim 300^{\\circ}$) with a diameter of $\\sim 4.5\\, {\\rm arcsec}$. The discovery was made serendipitously from inspecting Dark Energy Camera (DECam) archive imaging data. Confirmation of the object nature has been obtained by deriving spectroscopic redshifts for both components, lens and source, from observations at the $10.4$ m Gran Telescopio CANARIAS (GTC) with the spectrograph OSIRIS. The lens, a massive early-type galaxy, has a redshift of ${\\rm z}=0.581$ while the source is a starburst galaxy with redshift of ${\\rm z}=1.165$. The total enclosed mass that produces the lensing effect has been estimated to be ${\\rm M_{tot}=(1.86 \\pm 0.23) \\,\\cdot 10^{12}\\, {\\rm M_{\\odot}}}$.

  17. 2008 City of Baltimore Lidar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the spring of 2008, the City of Baltimore expressed an interest to upgrade the City GIS Database with mapping quality airborne LiDAR data. The City of Baltimore...

  18. Cities, Towns and Villages, City Limits of City of Dubuque, IA, Published in 2007, City of Dubuque.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Cities, Towns and Villages dataset, was produced all or in part from Published Reports/Deeds information as of 2007. It is described as 'City Limits of City of...

  19. Solar Power Satellites

    CERN Document Server

    Flournoy, Don M

    2012-01-01

    Communication satellites are a $144 billion industry. Is there any space-based industry that could possibly beat that market? 'Solar Power Satellites' shows why and how the space satellite industry will soon begin expanding its market from relaying signals to Earth to generating energy in space and delivering it to the ground as electricity. In all industrialized nations, energy demand is growing exponentially. In the developing world, the need for energy is as basic as food and water. The Sun's energy is available everywhere, and it is non-polluting. As business plans demonstrate its technical feasibility, commercial potential, and environmental acceptability, every country on Earth will look to space for the power it needs.

  20. Geostationary satellites collocation

    CERN Document Server

    Li, Hengnian

    2014-01-01

    Geostationary Satellites Collocation aims to find solutions for deploying a safe and reliable collocation control. Focusing on the orbital perturbation analysis, the mathematical foundations for orbit and control of the geostationary satellite are summarized. The mathematical and physical principle of orbital maneuver and collocation strategies for multi geostationary satellites sharing with the same dead band is also stressed. Moreover, the book presents some applications using the above algorithms and mathematical models to help readers master the corrective method for planning station keeping maneuvers. Engineers and scientists in the fields of aerospace technology and space science can benefit from this book. Hengnian Li is the Deputy Director of State Key Laboratory of Astronautic Dynamics, China.

  1. ESA's satellite communications programme

    Science.gov (United States)

    Bartholome, P.

    1985-02-01

    The developmental history, current status, and future plans of the ESA satellite-communications programs are discussed in a general survey and illustrated with network diagrams and maps. Consideration is given to the parallel development of national and European direct-broadcast systems and telecommunications networks, the position of the European space and electronics industries in the growing world market, the impact of technological improvements (both in satellite systems and in ground-based networks), and the technological and commercial advantages of integrated space-terrestrial networks. The needs for a European definition of the precise national and international roles of satellite communications, for maximum speed in implementing such decisions (before the technology becomes obsolete), and for increased cooperation and standardization to assure European equipment manufacturers a reasonable share of the market are stressed.

  2. AVS on satellite

    Science.gov (United States)

    Zhao, Haiwu; Wang, Guozhong; Hou, Gang

    2005-07-01

    AVS is a new digital audio-video coding standard established by China. AVS will be used in digital TV broadcasting and next general optical disk. AVS adopted many digital audio-video coding techniques developed by Chinese company and universities in recent years, it has very low complexity compared to H.264, and AVS will charge very low royalty fee through one-step license including all AVS tools. So AVS is a good and competitive candidate for Chinese DTV and next generation optical disk. In addition, Chinese government has published a plan for satellite TV signal directly to home(DTH) and a telecommunication satellite named as SINO 2 will be launched in 2006. AVS will be also one of the best hopeful candidates of audio-video coding standard on satellite signal transmission.

  3. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three......-axis magnetometer, three piezoelectric gyros, and four reaction wheels in a tetrahedron configuration. The operation of the spacecraft is fully autonomous. The data flow between the transducers and the onboard computer placed physically outside the satellite is provided by a radio link. The purpose...

  4. Stable rings generated by their units

    Directory of Open Access Journals (Sweden)

    Huanyin Chen

    2001-01-01

    Full Text Available We introduce the class of rings satisfying (m,1-stable range and investigate equivalent characterizations of such rings. These give generalizations of the corresponding results by Badawi (1994, Ehrlich (1976, and Fisher and Snider (1976.

  5. How to Remove a Stuck Ring Safely

    Science.gov (United States)

    ... Gardening Safety Turkey Carving Removing a Ring Español Artritis de la base del pulgar Dedo en gatillo ... Gardening Safety Turkey Carving Removing a Ring Español Artritis de la base del pulgar Dedo en gatillo ...

  6. On π-regularity of General Rings

    Institute of Scientific and Technical Information of China (English)

    CHEN WEI-XING; CUI SHU-YING

    2010-01-01

    A general ring means an associative ring with or without identity. An idempotent e in a general ring I is called left (right) semicentral if for every x∈ I,xe = exe (ex = exe). And I is called semiabelian ff every idempotent in I is left or right semicentral. It is proved that a semiabelian general ring I is π-regular if and only ff the set N(I) of nilpotent elements in I is an ideal of I and I/N(I) is regular. It follows that if I is a semiabelian general ring and K is an ideal of I,then I is π-regular if and only if both K and I/K are r-regular. Based on this we prove that every semiabelian GVNL-ring is an SGVNL-ring. These generalize several known results on the relevant subject. Furthermore we give a characterization of a semiabelian GVNL-ring.

  7. International Tree Ring Data Bank (ITRDB)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Tree ring data from the International Tree Ring Data Bank and World Data Center for Paleoclimatology archives. Data include raw treering measurements (most are...

  8. Experiments with vortex rings in air

    Science.gov (United States)

    Hernández, R. H.; Cibert, B.; Béchet, C.

    2006-09-01

    We report quantitative experimental measurements of the instability of vortex rings generated in air. Vortex rings are created by pushing air through the circular orifice of a cylindrical cavity with a flat piston driven by a loudspeaker. Hot-wire anemometry provides accurate measurements of the velocity profile at all stages of the ring formation including stable and unstable rings. Flow visualization using a laser light sheet shows that the initially undisturbed vortex ring is progressively deformed in the azimuthal direction giving rise to a wavy azimuthal and periodic pattern in the circumference of the ring. The wavy pattern is steady, i.e., it does not rotate or translate during the ring's motion. However as the vortex motion progresses in the axial direction, the displaced portions of the ring are convected away from the initial undisturbed position and the wavy pattern grows with local Reynolds number.

  9. Persistent currents in normal metal rings.

    Science.gov (United States)

    Bluhm, Hendrik; Koshnick, Nicholas C; Bert, Julie A; Huber, Martin E; Moler, Kathryn A

    2009-04-03

    The authors have measured the magnetic response of 33 individual cold mesoscopic gold rings, one ring at a time. The response of some sufficiently small rings has a component that is periodic in the flux through the ring and is attributed to a persistent current. Its period is close to h/e, and its sign and amplitude vary between rings. The amplitude distribution agrees well with predictions for the typical h/e current in diffusive rings. The temperature dependence of the amplitude, measured for four rings, is also consistent with theory. These results disagree with previous measurements of three individual metal rings that showed a much larger periodic response than expected. The use of a scanning SQUID microscope enabled in situ measurements of the sensor background. A paramagnetic linear susceptibility and a poorly understood anomaly around a zero field are attributed to defect spins.

  10. Kernel representations for behaviors over finite rings

    NARCIS (Netherlands)

    Kuijper, M.; Pinto, R.; Polderman, J.W.; Yamamoto, Y.

    2006-01-01

    In this paper we consider dynamical systems finite rings. The rings that we study are the integers modulo a power of a given prime. We study the theory of representations for such systems, in particular kernel representations.

  11. The Structure of gr-simple Rings

    Institute of Scientific and Technical Information of China (English)

    朱彬

    2003-01-01

    A characterization of gr-simple rings is given by using the notion of componentwise-dense subrings of a full matrix ring over a division ring. As a conse-quence, any G-graded full matrix ring over a division ring is isomorphic to a dense subring of a full matrix ring with a good G-grading. Some conditions for a grading of a full matrix ring to be isomorphic to a good one are given, which generalize some results in: Dáscáscu, S., Lon, B., Niǎstǎsescu, C. and Montes, J. R., Group gradingson full matrix rings, J. Algebra, 220(1999), 709-728.

  12. On Splitting Rings for Azumaya Skew Polynomial Rings

    Institute of Scientific and Technical Information of China (English)

    George Szeto; Lianyong Xue

    2001-01-01

    Let B be a ring with 1, p an automorphism of B of order n for some integer n, and B[x; p] the skew polynomial ring in x over B such that 1, x,x2,... ,xn-1 are independent over B and xn ∈ U(Bp), where Bp is the set of elements in B fixed under p and U(Bρ) is the set of all units in Bρ. Let -ρ be the inner automorphism of B[x; p] induced by x. Assume n is a unit in B. It is shown that, for a -ρ-Galois extension B[x; p] over (B[x; ρ])-ρ (resp., a DeMeyer-Kanzaki Galois extention B over Bp), B[x; ρ] is Azumaya if and only if (B[x; ρ])-ρ (resp.,B) is Azumaya, and some splitting rings of B[x; ρ], (B[x; ρ])-ρ and B coincide.

  13. GPS satellite surveying

    CERN Document Server

    Leick, Alfred; Tatarnikov, Dmitry

    2015-01-01

    THE MOST COMPREHENSIVE, UP-TO-DATE GUIDE ON GPS TECHNOLOGY FOR SURVEYING Three previous editions have established GPS Satellite Surveying as the definitive industry reference. Now fully updated and expanded to reflect the newest developments in the field, this Fourth Edition features cutting-edge information on GNSS antennas, precise point positioning, real-time relative positioning, lattice reduction, and much more. Expert authors examine additional tools and applications, offering complete coverage of geodetic surveying using satellite technologies. The past decade has seen a major evolut

  14. Declassified intelligence satellite photographs

    Science.gov (United States)

    ,

    1998-01-01

    Recently declassified photographs from spy satellites are an important addition to the record of the Earth?s land surface held by the U.S. Geological Survey (USGS). More than 800,000 high-resolution photos taken between 1959 through 1972 were made available by Executive Order of the President. The collection is held at the USGS EROS Data Center, near Sioux Falls, S. Dak., and are offered for public sale. For some purposes in earth science studies, these photos extend the record of changes in the land surface another decade back in time from the advent of the Landsat earth-observing satellite program.

  15. Oceanography from satellites

    Science.gov (United States)

    Wilson, W. S.

    1981-01-01

    It is pointed out that oceanographers have benefited from the space program mainly through the increased efficiency it has brought to ship operations. For example, the Transit navigation system has enabled oceanographers to compile detailed maps of sea-floor properties and to more accurately locate moored subsurface instrumentation. General descriptions are given of instruments used in satellite observations (altimeter, color scanner, infrared radiometer, microwave radiometer, scatterometer, synthetic aperture radar). It is pointed out that because of the large volume of data that satellite instruments generate, the development of algorithms for converting the data into a form expressed in geophysical units has become especially important.

  16. Satellite oceanography - The instruments

    Science.gov (United States)

    Stewart, R. H.

    1981-01-01

    It is pointed out that no instrument is sensitive to only one oceanographic variable; rather, each responds to a combination of atmospheric and oceanic phenomena. This complicates data interpretation and usually requires that a number of observations, each sensitive to somewhat different phenomena, be combined to provide unambiguous information. The distinction between active and passive instruments is described. A block diagram illustrating the steps necessary to convert data from satellite instruments into oceanographic information is included, as is a diagram illustrating the operation of a radio-frequency radiometer. Attention is also given to the satellites that carry the various oceanographic instruments.

  17. Integrated Satellite-HAP Systems

    DEFF Research Database (Denmark)

    Cianca, Ernestina; De Sanctis, Mauro; De Luise, Aldo

    2005-01-01

    for an efficient hybrid terrestrial-satellite communication system. Two integrated HAP-satellite scenarios are presented, in which the HAP is used to overcome some of the shortcomings of satellite- based communications. Moreover, it is shown that the integration of HAPs with satellite systems can be used......Thus far, high-altitude platform (HAP)-based systems have been mainly conceived as an alternative to satellites for complementing the terrestrial network. This article aims to show that HAP should no longer be seen as a competitor technology by investors of satellites, but as a key element...

  18. Nonlinear analysis of ring oscillator circuits

    KAUST Repository

    Ge, Xiaoqing

    2010-06-01

    Using nonlinear systems techniques, we analyze the stability properties and synchronization conditions for ring oscillator circuits, which are essential building blocks in digital systems. By making use of its cyclic structure, we investigate local and global stability properties of an n-stage ring oscillator. We present a sufficient condition for global asymptotic stability of the origin and obtain necessity if the ring oscillator consists of identical inverter elements. We then give a synchronization condition for identical interconnected ring oscillators.

  19. Dysphagia due to Multiple Esophageal Rings

    Directory of Open Access Journals (Sweden)

    Stephen N Sullivan

    1995-01-01

    Full Text Available A 27-year-old Saudi man with dysphagia due to multiple esophageal rings is reported and the literature reviewed. Dysphagia due to multiple esophageal rings is very rare. Only 15 cases have been reported. The patient is usually male and has had dysphagia for many years when presenting. The cause of the rings is unknown. Theories to explain dysphagia are that the rings are either congenital or an unusual manifestation of gastroesophageal reflux.

  20. Polar ring galaxies formation and properties

    CERN Document Server

    Bournaud, F; Bournaud, Frederic; Combes, Francoise

    2003-01-01

    Formation scenarios for polar ring galaxies are studied through N-body simulatio ns that are compared with existing observations. It is shown that polar rings ar e likely to be formed by tidal accretion of the polar material from a gas rich d onor galaxy. The distribution of dark matter in polar ring galaxies is studied: dark halos seem to be flattened towards the polar rings.