Now showing items 21-40 of 574

    • Dynamic effects of restoring footpoint symmetry on closed magnetic field lines 

      Reistad, Jone Peter; Østgaard, Nikolai; Tenfjord, Paul; Laundal, Karl Magnus; Snekvik, Kristian; Haaland, Stein; Milan, Steve; Oksavik, Kjellmar; Frey, H. U.; Grokott, A. (AGU Publications, 2016-05-05)
      Here we present an event where simultaneous global imaging of the aurora from both hemispheres reveals a large longitudinal shift of the nightside aurora of about 3 h, being the largest relative shift reported on from ...
      Journal article
    • A Nonlinear Differential Equation Solver With Potential Application to Pelton Turbines 

      Tveit, Jesper (The University of Bergen, 2016-05-02)
      The focus in this thesis is the development and implementation of a new method for solving nonlinear differential equations on a grid. The method’s novelty lies in the way it represents continuously distributed variables ...
      Doctoral thesis
    • On the composite response of the MLT to major sudden stratospheric warming events with elevated stratopause 

      Limpasuvan, Varavut; Orsolini, Yvan; Chandran, Amal; Garcia, Rolando R.; Smith, Anne K. (Wiley, 2016-05)
      Based on a climate-chemistry model (constrained by reanalyses below ~50 km), the zonal-mean composite response of the mesosphere and lower thermosphere (MLT) to major sudden stratospheric warming events with elevated ...
      Journal article
    • Ionization dynamics beyond the dipole approximation induced by the pulse envelope 

      Simonsen, Aleksander; Kjellsson, Tor; Førre, Morten; Lindroth, Eva; Selstø, Sølve (American Physical Society, 2016-05)
      When atoms and molecules are ionized by laser pulses of finite duration and increasingly high intensities, the validity of the much-used dipole approximation, in which the spatial dependence and magnetic component of the ...
      Journal article
    • Ground-based and Satellite Remote Sensing of Atmospheric Aerosols and Ultraviolet Solar Radiation 

      Muyimbwa, Dennis (The University of Bergen, 2016-04-08)
      Satellite remote sensed data have been used to determine the aerosol climatology and to investigate the influence of the aerosol index (AI) on the ultraviolet (UV) index in coastal land areas in Serrekunda (13.28◦ N, 16.34◦ ...
      Doctoral thesis
    • Mechanisms responsible for asymmetric aurora between the conjugate hemispheres 

      Reistad, Jone Peter (The University of Bergen, 2016-04)
      The work presented in this thesis is part of ongoing research within one of the research groups at the Birkeland Centre for Space Science (BCSS) at the Department of Physics and Technology, University of Bergen. Members ...
      Doctoral thesis
    • Enhanced Oil Recovery by CO2 Injection in Fractured Reservoirs. Emphasis on Wettability and Water Saturation 

      Steinsbø, Marianne (The University of Bergen, 2016-03-04)
      The work presented in this Thesis is part of ongoing research on Enhanced Oil Recovery (EOR) in fractured reservoirs within the reservoir physics research group at the Department of Physics and Technology, University of ...
      Doctoral thesis
    • Investigation into the impact of solid surfaces in aqueous systems 

      Jensen, Bjørnar (The University of Bergen, 2016-03-03)
      Global warming is upon us. The scientific community is searching for methods of slowing down, preventing and reversing its effects. Carbon dioxide have been at the center of attention the last few decades, being the main ...
      Doctoral thesis
    • The global potential for carbon capture and storage from forestry 

      Ni, Yuanming; Eskeland, Gunnar; Giske, Jarl; Hansen, Jan Petter (Springer, 2016-02-26)
      Background: Discussions about limiting anthropogenic emissions of CO2 often focus on transition to renewable energy sources and on carbon capture and storage (CCS) of CO2. The potential contributions from forests, forest ...
      Journal article
    • Spectral albedo and transmittance of thin young Arctic sea ice 

      Taskjelle, Torbjørn; Hudson, Stephen R.; Granskog, Mats A.; Nicolaus, Marcel; Lei, Ruibo; Gerland, Sebastian; Stamnes, Jakob J.; Hamre, Børge (Wiley, 2016-01)
      Spectral albedo and transmittance in the range 400–900nm were measured on three separate dates on less than 15 cm thick new Arctic sea ice growing on Kongsfjorden, Svalbard at 78:9°N, 11:9°E. Inherent optical properties, ...
      Journal article
    • A new population of terrestrial gamma-ray flashes in the RHESSI data 

      Østgaard, Nikolai; Albrechtsen, Kjetil; Gjesteland, Thomas; Collier, Andrew B. (AGU Publications, 2015-12-23)
      Terrestrial gamma-ray flashes (TGFs) are the most energetic photon phenomenon occurring naturally on Earth. An outstanding question is as follows: Are these flashes just a rare exotic phenomenon or are they an intrinsic ...
      Journal article
    • Visualization and interpretation of methane hydrate growth and dissociation in synthetic porous media 

      Flatlandsmo, Josef (The University of Bergen, 2015-12-22)
      Sedimentary natural gas hydrates might play an important role in the future energy mix and the impact of methane release from natural gas hydrates can be significant also with respect to climate change. Vast amounts of ...
      Master thesis
    • Radiation treatment monitoring using multimodal functional imaging: PET/CT (18F-Fluoromisonidazole & 18F-Fluorocholine) and DCE-US 

      Arteaga-Marrero, Natalia; Brekke Rygh, Cecilie; Mainou-Gomez, Jose Francisco; Adamsen, Tom Christian; Lutay, Nataliya; Reed, Rolf K; Olsen, Dag Rune (BioMed Central, 2015-12-18)
      Background: This study aims to assess the effect of radiation treatment on the tumour vasculature and its downstream effects on hypoxia and choline metabolism using a multimodal approach in the murine prostate tumour model ...
      Journal article
    • Observation of intrinsically bright terrestrial gamma ray flashes from the Mediterranean basin 

      Gjesteland, Thomas; Østgaard, Nikolai; Laviola, Sante; Miglietta, M M; Arnone, Enrico; Marisaldi, Martino; Fuschino, F; Collier, Andrew B.; Fabro, F; Montanya, J (AGU Publications, 2015-12-14)
      We present three terrestrial gamma ray flashes (TGFs) observed over the Mediterranean basin by the Reuven Ramaty High Energy Solar Spectroscope Imager (RHESSI) satellite. Since the occurrence of these events in the ...
      Journal article
    • Autonomic Operation of a Large High Performance On-Line Compute Cluster 

      Haaland, Øystein Senneset (The University of Bergen, 2015-12-10)
      A High-Level Trigger (HLT) system is composed of both hardware and software. Designing the physical layout of the cluster mainly concerns the hardware; node distribution, network layout, estimation of power requirements, ...
      Doctoral thesis
    • Investigation of temperature rise in substation during emergency 

      Knutsen, Per Christian (The University of Bergen, 2015-12-08)
      During a TTS verification at Kårstø Processing Plant there where raised a non-conformity to Statoil specification and requirements with regard to temperature rise in substations when HVAC is shut down. One could not ...
      Master thesis
    • Estimation of cold plasma outflow during geomagnetic storms 

      Haaland, Stein; Eriksson, A.; Maes, L.; Baddeley, Lisa; Barakat, A.; Chappell, R.; Eccles, V.; Johnsen, C.; Lybekk, Bjørn; Li, K.; Pedersen, A; Schunk, R.; Welling, D. (Wiley, 2015-12-01)
      Low-energy ions of ionospheric origin constitute a significant contributor to the magnetospheric plasma population. Measuring cold ions is difficult though. Observations have to be done at sufficiently high altitudes and ...
      Journal article
    • In-flight calibration of NOAA POES proton detectors - Derivation of the MEPED correction factors 

      Sandanger, Marit Irene J.; Ødegaard, Linn-Kristine Glesnes; Tyssøy, Hilde Nesse; Stadsnes, Johan; Søraas, Finn; Oksavik, Kjellmar; Aarsnes, Kjell (Wiley, 2015-11-25)
      The MEPED instruments on board the NOAA POES and MetOp satellites have been continuously measuring energetic particles in the magnetosphere since 1978. However, degradation of the proton detectors over time leads to an ...
      Journal article
    • The interaction between transpolar arcs and cusp spots 

      Fear, Robert C.; Milan, Steve; Carter, Jenny A.; Maggiolo, Romain (AGU Publications, 2015-11-25)
      Transpolar arcs and cusp spots are both auroral phenomena which occur when the interplanetary magnetic field is northward. Transpolar arcs are associated with magnetic reconnection in the magnetotail, which closes magnetic ...
      Journal article
    • Solar radiation energy on the Tibetan plateau 

      Gelsor, Nuozhen (The University of Bergen, 2015-11-20)
      To gain a thorough knowledge of the solar energy resources on the Tibetan Plateau, measured and modeled solar irradiance levels on the Plateau from July 2010 to September 2013 are considered. The Tibetan Plateau lies in ...
      Master thesis