Artikler, rapporter og annet (fysikk og teknologi): Nye registreringer

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    • CFD-DEM and Experimental Study of Bubbling in a Fluidized Bed 

      Khawaja, Hassan Abbas (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12)
      In this study, phenomenon of bubbling is investigated using CFD-DEM and experiments. A CFD-DEM simulation is setup to model the fluidized beds of different sizes. Geldart D particles of 1.2 mm diameter and 1000 Kg/m3 density are modelled. Study revealed different types of fluidization regimes as stated in the literature. An experimental setup is built to obtain the results for the comparison. ...

    • Short-Time Ice Drift and Deformation Measurements Using Multi-Mission Synethetic Aperture Radar 

      Kræmer, Thomas; Brekke, Camilla (Journal article; Tidsskriftartikkel, 2015-06)
      Norway is in a good position regarding frequent access to synthetic aperture radar data. A Norwegian– Canadian agreement provides large quotas of RADARSAT-2 images used operationally by e.g. the Norwegian Ice Service. More recently, Norway’s participation in the Copernicus program also allows rapid access to SENTINEL-1A data. By combining these data sources we can get satellite time series ...

    • Statistical Unmixing of SAR Images 

      Anfinsen, Stian Normann (Journal article; Tidsskriftartikkel, 2016-02-03)
      A method is presented which uses logarithmic statistics to detect and characterise class mixtures and targets in background clutter in synthetic aperture radar (SAR) images. Mixtures of ground cover types show up as extreme radar texture in statistical analysis of SAR images. Instead of modelling this as a spatially nonstationary radar cross section, this paper demonstrates how a mixture model ...

    • Linear scaling Coulomb interaction in the multiwavelet basis, a parallel implementation 

      Jensen, Stig Rune; Juselius, Jonas; Durdek, Antoine Pacifique Romain; Flå, Tor; Wind, Peter; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-08-27)
      We present a parallel and linear scaling implementation of the calculation of the electrostatic potential arising from an arbitrary charge distribution. Our approach is making use of the multi-resolution basis of multiwavelets. The potential is obtained as the direct solution of the Poisson equation in its Green’s function integral form. In the multiwavelet basis, the formally non local ...

    • Mesospheric temperatures and sodium properties measured with the ALOMAR Na lidar compared with WACCM 

      Dunker, Tim; Hoppe, Ulf-Peter; Feng, Wuhu; Plane, John M.C.; Marsh, Daniel R. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-16)
      We present a comparison of the temperature and sodium layer properties observed by the ALOMAR Na lidar (69.3°N, 16.0°E) and simulated by the Whole Atmosphere Community Climate Model with specified dynamics and implemented sodium chemistry (WACCM-Na). To constrain the meteorological fields below 60 km, we use MERRA and GEOS-5. For the years 2008 to 2012, we analyse daily averages of temperature ...

    • Multi-radar observations of polar mesosphere summer echoes during the PHOCUS campaign on 20-22 July 2011 

      Belova, Evgenia; Kirkwood, Sheila; Latteck, Ralph; Zecha, Marius; Pinedo Nava, Henry; Hedin, Jonas; Gumbel, Jörg (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-06-27)
      During the PHOCUS rocket campaign, on 20-22 July 2011, the observations of polar mesosphere summer echoes (PMSE) were made by three mesosphere-stratosphere-troposphere radars, operating at about 50 MHz. One radar, ESRAD is located at Esrange in Sweden, where the rocket was launched, two other radars, MAARSY and MORRO, are located 250 km north-west and 200 km north of ESRAD, respectively, on the other ...

    • Magnitude of extreme heat waves in present climate and their projection in a warming world 

      Russo, S.; Dosio, A.; Graversen, Rune; Sillmann, Jana; Carrao, H.; Dunbar, M.B.; Singleton, Andrew B.; Montagna, P.; Barbosa, P.; Vogt, Jürgen V. (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      An extreme heat wave occurred in Russia in the summer of 2010. It had serious impacts on humans and natural ecosystems, it was the strongest recorded globally in recent decades and exceeded in amplitude and spatial extent the previous hottest European summer in 2003. Earlier studies have not succeeded in comparing the magnitude of heat waves across continents and in time. This study introduces a new ...

    • Corrigendum to "Development of the mesospheric Na layer at 69 degrees N during the Geminids meteor shower 2010", published in Ann.Geophys., 31, 61-73, 2013 

      Dunker, Tim; Hoppe, Ulf-Peter; Stober, Gunter; Rapp, Markus (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)

    • Monitoring glacier changes using multitemporal multipolarization SAR images 

      Akbari, Vahid; Doulgeris, Anthony Paul; Eltoft, Torbjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)

    • Simulation of Anti-reflection Coated Carbonaceous Spectrally Selective Absorbers 

      Chen, Zhonghua; Amitap, Jain; Boström, Tobias (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-11-22)

    • 20 years of research on the Alcator C-Mod tokamak 

      Greenwald, Martin; Bader, A; Baek, S; Bakhtiari, M; Barnard, H; Beck, W; Bergerson, W; Bespamyatnov, I; Bonoli, P; Brower, D; Brunner, D; Burke, W; Candy, J; Churchill, M; Cziegler, I; Diallo, A; Dominguez, A; Duval, B; Edlund, E; Ennever, P; Ernst, D; Faust, I; Fiore, C; Fredian, T; Garcia, Odd Erik; Gao, C; Goetz, J; Golfinopoulos, T; Granetz, R; Grulke, O; Hartwig, Z; Horne, S; Howard, N; Hubbard, A; Hughes, J; Hutchinson, I; Irby, J; Izzo, V; Kessel, C; Labombard, B; Lau, C; Li, C; Lin, Y; Lipschultz, B; Loarte, A; Marmar, E; Mazurenko, A; McCracken, G; McDermott, R; Meneghini, O; Mikkelsen, D; Mossessian, D; Mumgaard, R; Myra, J; Nelson-Melby, E; Ochoukov, R; Olynyk, G; Parker, R; Pitcher, S; Podpaly, Y; Porkolab, M; Reinke, M; Rice, J; Rowan, W; Schmidt, A; Scott, S; Shiraiwa, S; Sierchio, J; Smick, N; Snipes, JA; Snyder, P; Sorbom, B; Stillerman, J; Sung, C; Takase, Y; Tang, V; Terry, J; Terry, D; Theiler, C; Tronchin-James, A; Tsujii, N; Vieira, R; Walk, J; Wallace, G; White, A; Whyte, D; Wilson, J; Wolfe, S; Wright, G; Wright, J; Wukitch, S; Zweben, S (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)

    • Velocity scaling for filament motion in scrape-off layer plasmas 

      Kube, Ralph; Garcia, Odd Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)

    • Effect of dynamical friction on interchange motion of plasma filaments 

      Kube, Ralph; Garcia, Odd Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)

    • Convergence of statistical moments of particle density time series in scrape-off layer plasmas 

      Kube, Ralph; Garcia, Odd Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)

    • Blob sizes and velocities in the Alcator C-Mod scrape-off layer 

      Kube, Ralph; Garcia, Odd Erik; LaBombard, Brian; Terry, J.L; Zweben, Stewart (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Gas-puff imaging data is used to investigate the dynamics of blob-like structures in the scrape-off layer of Alcator C-Mod. A blob-tracking algorithm is developed and used to compute blob propagation velocities and cross-field sizes for a series of discharges where the line-averaged particle density View the MathML source is varied. We find that the mean radial blob velocity increases from View the ...

    • Estimation of statistical moments for single point measurements in the Scrape Off Layer 

      Kube, Ralph; Garcia, Odd Erik (Conference object; Konferansebidrag, 2014-03-17)

    • Improving Doppler frequency estimation from Envisat data 

      Kræmer, Thomas; Johnsen, Harald; Brekke, Camilla (Conference object; Konferansebidrag, 2014)

    • An Automatic U-distribution and Markov Random Field Segmentation Algorithm for PolSAR Images 

      Doulgeris, Anthony Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)

    • Long-range memory in internal and forced dynamics of millennium-long climate model simulations 

      Østvand, Lene; Nilsen, Tine; Rypdal, Kristoffer; Divine, Dmitry, V.; Rypdal, Martin wibe (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      Northern Hemisphere (NH) temperature records from a palaeoclimate reconstruction and a number of millennium-long climate model experiments are investigated for long-range memory (LRM). The models are two Earth system models and two atmosphere–ocean general circulation models. The periodogram, detrended fluctuation analysis and wavelet variance analysis are applied to examine scaling properties ...

    • Statistical significance of rising and oscillatory trends in global ocean and land temperature in the past 160 years 

      Østvand, Lene; Rypdal, Kristoffer; Rypdal, Martin (Journal article; Tidsskriftartikkel, 2014-10-30)
      Various interpretations of the notion of a trend in the context of global warming are discussed, contrasting the difference between viewing a trend as the deterministic response to an external forcing and viewing it as a slow variation which can be separated from the background spectral continuum of long-range persistent climate noise. The emphasis in this paper is on the latter notion, and a ...