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Träfflista för sökning "WFRF:(Grönlund Rasmus) ;spr:eng"

Sökning: WFRF:(Grönlund Rasmus) > Engelska

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1.
  • Andersson, Mats, et al. (författare)
  • Laser spectroscopy of gas in scattering media at scales ranging from kilometers to millimeters
  • 2007
  • Ingår i: Laser Physics. - MAIK Nauka. - 1054-660X. ; 17:7, s. 893-902
  • Tidskriftsartikel (refereegranskat)abstract
    • Free gases are characterized by their narrow line width, and they can conveniently be studied by laser spectroscopy. The present paper discusses the monitoring of such ambient pressure gases, which are dispersed in scattering media such as aerosol-laden atmospheres, solids, or liquids. Atmospheric work basically constitutes the well-known field of differential absorption lidar (DIAL), while the study of free gas in solids and liquids was initiated more recently under the name of GASMAS (GAs in Scattering Media Absorption Spectroscopy). We discuss the connections between the two techniques, which are extensively used in our labortory. Thus, we span the field from trace-gas mapping of gases in the lower atmosphere to gas studies in construction materials, food products, and the human body. We show that the basic ideas are very similar, while the spatial and temporal scales vary greatly.
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3.
  • Bengtsson, Magnus, et al. (författare)
  • Fluorescence lidar imaging of fungal growth on high-voltage outdoor composite insulators
  • 2005
  • Ingår i: Optics and lasers in engineering. - 0143-8166. ; 43:6, s. 624-632
  • Tidskriftsartikel (refereegranskat)abstract
    • Remote fluorescence imaging of fungal growth on polymeric high-voltage insulators was performed using a mobile lidar system with a laser wavelength of 355 nm. Insulator areas contaminated by fungal growth could be distinguished from clean surfaces and readily be imaged. The experiments were supported by detailed spectral studies performed in laboratory using a fibre-optic fluorosensor incorporating an optical multi-channel analyser system (OMA) and a nitrogen laser emitting radiation at 33 7 nm.
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4.
  • Bengtsson, Magnus, et al. (författare)
  • Lidar fluorescence measurements of algal growth on electrical insulators
  • 2003
  • Ingår i: 2003 Conference on Lasers and Electro-Optics Europe (CLEO/Europe 2003) (IEEE Cat. No.03TH8666). - IEEE. - 0-7803-7734-6 ; s. 473-473
  • Konferensbidrag (refereegranskat)abstract
    • Fluorescence measurements using lidar techniques have been shown to be useful for monitoring of algal growth on e.g. historical monuments. In this experiment similar measurements were performed on electrical insulators to examine the correlation between algal growth and the quality of the insulator, a factor of importance in the high-voltage grid management
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5.
  • Bengtsson, Magnus, et al. (författare)
  • Remote laser-induced breakdown spectroscopy for the detection and removal of salt on metal and polymeric surfaces
  • 2006
  • Ingår i: Applied Spectroscopy. - Society for Applied Spectroscopy. - 0003-7028. ; 60:10, s. 1188-1191
  • Tidskriftsartikel (refereegranskat)abstract
    • The detection of contamination such as salt in outdoor high-voltage insulator systems and its subsequent removal are vital for a reliable transmission of electric power. Remote detection of salt on a copper metal surface was carried out by using a mobile laser-induced breakdown spectroscopy (LIBS) Lidar system with a laser wavelength of 355 nm. Detection of salt on a polymeric high-voltage insulator was obtained when an additional lens was inserted into the beam path, and the number of photons that was detected could be calculated by using a calibrated white light source. Ablative cleaning could readily be carried out with LIBS and was verified by observing the disappearance of the sodium D-line emission.
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6.
  • Bennett, M, et al. (författare)
  • Joint application of Doppler Lidar and differential absorption lidar to estimate the atomic mercury flux from a chlor-alkali plant
  • 2006
  • Ingår i: Atmospheric Environment. - Elsevier Science Ltd. - 1352-2310. ; 40:4, s. 664-673
  • Tidskriftsartikel (refereegranskat)abstract
    • We have combined differential absorption lidar (DIAL) measurements of mercury concentrations downwind of a chloralkali plant (Rosignano Solvay) with measurements of wind profiles made with a Doppler Lidar based on modern fibreoptic technology. Since the flux of pollutant is equal to the cross-wind integral of the product of concentration and wind speed, this should permit us to make a more precise estimate of the fugitive emission of mercury from the plant than could be obtained by using anemometer measurements of the wind. The flux was estimated to be 54g Hgh(-1) using an anemometer on the plant building; 49g Hgh(-1) using an anemometer on a nearby 10m mast; and 48g Hgh(-1) using wind speed corrections estimated from the Doppler Lidar measurements. Because of difficulties with the range resolution of the Doppler Lidar, the precision of this estimate was not as good as it should have been, though the difference from the rooftop anemometer remains statistically significant. Corrections of this magnitude are irrelevant to the Rosignano plant, where the emission rate varies strongly with the meteorological conditions. Where a precise estimate of a steady flux is required, however, reliable measurements of the wind profile in the wake of the source are essential. Doppler Lidar provides a possible method for acquiring such measurements. (c) 2005 Elsevier Ltd. All rights reserved.
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9.
  • Dernfalk, Andreas, 1975-, et al. (författare)
  • Laser-induced fluorescence spectroscopy for detection of biological contamination on composite insulators
  • 2003
  • Ingår i: In Proc. 13th International Symposium on High Voltage Engineering, Delft, Netherlands.
  • Konferensbidrag (refereegranskat)abstract
    • A new technique for remote detection of biological contamination on high-voltage outdoor insulators has been investigated. The technique, which is based on laser-induced fluorescence (LIF) spectroscopy, has been applied to study surfaces of real silicon rubber insulators from a distance of approximately 60 m. Measurements were performed outdoors on a number of clean, as well as, biologically contaminated insulators. Several types of biological contamination were included, as five of the studied insulators had become covered when installed in Sweden, and another three had been contaminated by fungal growth in laboratory. Fluorescence spectra obtained from the surfaces of the described insulators are presented and the applicability of the technique is discussed and compared with photographic methods.
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10.
  • Grönlund, Rasmus, et al. (författare)
  • Elemental mercury emissions from chlor-alkali plants measured by lidar techniques
  • 2005
  • Ingår i: ATMOSPHERIC ENVIRONMENT. - PERGAMON-ELSEVIER SCIENCE LTD. - 1352-2310. ; 39:39, s. 7474-7480
  • Tidskriftsartikel (refereegranskat)abstract
    • Differential absorption lidar (DIAL) techniques have been utilized to measure elemental gaseous mercury fluxes from mercury cell chlor-alkali (MCCA) plants as a part of the European Union funded European mercury emissions from chlor-alkali plants (EMECAP) project. Three plants have been selected as study objects and a total of six measurement campaigns have been performed, one intercalibration campaign and five flux evaluation campaigns, in both winter and summer. The measurements were carried out using the Swedish optical parametric oscillator-(OPO) based mobile lidar system developed at Lund Institute of Technology. The study shows large differences in the mercury emissions measured in winter or summer and at the different plants. The average values for the campaigns ranged from 6 g h(-1) in the winter campaign at the Swedish plant to 54 g h(-1) in the summer campaign at the Italian plant.
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