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Träfflista för sökning "WFRF:(Grönlund Rasmus) ;spr:eng;conttype:(refereed);srt2:(2006)"

Sökning: WFRF:(Grönlund Rasmus) > Engelska > Refereegranskat > (2006)

  • Resultat 1-7 av 7
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1.
  • 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. - : SAGE Publications. - 1943-3530 .- 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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2.
  • 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 BV. - 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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3.
  • Grönlund, Rasmus, et al. (författare)
  • Laser-Induced Fluorescence for Assessment of Cultural Heritage
  • 2006
  • Konferensbidrag (refereegranskat)abstract
    • Remote imaging measurements of laser-induced fluorescence have been performed, with application towards cultural heritage. Measurement campaigns have been performed at, e.g., the Coliseum in Rome. Differences in fluorescence spectra from different points were found and images corresponding to different features could be produced for thematic mapping.
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4.
  • Grönlund, Rasmus, et al. (författare)
  • Remote imaging laser-induced breakdown spectroscopy and laser-induced fluorescence spectroscopy using nanosecond pulses from a mobile lidar system
  • 2006
  • Ingår i: Applied Spectroscopy. - : SAGE Publications. - 1943-3530 .- 0003-7028. ; 60:8, s. 853-859
  • Tidskriftsartikel (refereegranskat)abstract
    • A mobile lidar system was used in remote imaging laser-induced breakdown spectroscopy (LIBS) and laser-induced fluorescence (LIF) experiments. Also, computer-controlled remote ablation of a chosen area was demonstrated, relevant to cleaning of cultural heritage items. Nanosecond frequency-tripled Nd:YAG laser pulses at 355 nm were employed in experiments with a stand-off distance of 60 meters using pulse energies of up to 170 mJ. By coaxial transmission and common folding of the transmission and reception optical paths using a large computer-controlled mirror, full elemental imaging capability was achieved on composite targets. Different spectral identification algorithms were compared in producing thematic data based on plasma or fluorescence light.
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5.
  • Grönlund, Rasmus, et al. (författare)
  • Remote Multicolor Excitation Laser-Induced Fluorescence Imaging
  • 2006
  • Ingår i: Laser Chemistry. - : Hindawi Limited. - 0278-6273 .- 1476-3516. ; 2006, s. 57934-57934
  • Tidskriftsartikel (refereegranskat)abstract
    • Remote laser-induced fluorescence of stone materials was performed with application towards cultural heritage. Fluorescence was induced in targets ∼60 m from a mobile lidar laboratory by ultraviolet laser light, either from a frequency-tripled Nd:YAG laser or from an optical parametric oscillator system. Analysis was performed on combined spectra from the different excitation wavelengths and it was noted that important additional information can be gained when using several excitation wavelengths.
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6.
  • Grönlund, Rasmus, et al. (författare)
  • Studies of free gas in scattering media at micro- and macroscopic scales
  • 2006
  • Ingår i: Proceedings of International Symposium on Biophotonics, Nanophotonics and Metamaterials. ; , s. 42-45
  • Konferensbidrag (refereegranskat)abstract
    • Free gases in scattering media and different techniques for such studies are discussed in the present paper. Connections between two techniques that constitute a major research area at our laboratory are presented. One of the techniques concerns measurements of free gas in scattering media, such as human tissue and food products, on a small scale, while the other one is a technique for trace-gas measurements in the lower atmosphere. We show that the basic ideas are very similar and that, by applying the knowledge obtained on one scale to the other, little differences exist. This study motivates us to perform a measurement linking the two techniques.
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7.
  • Hällström, Jenny, et al. (författare)
  • Fluorescence lidar multispectral imaging for historical monuments, the Lateran Baptistery interdisciplinary project
  • 2006
  • Ingår i: [Host publication title missing].
  • Konferensbidrag (refereegranskat)abstract
    • Introduction For the future conservation, restoration and daily maintenance the need for developing non-destructive and in-situ investigations is vital. At Lund University in Sweden an interdisciplinary research project is being held aiming at, with the help of a mobile system of remote fluorescence lidar, survey and study the facades of historic monuments, and to develop the method and its application for the cultural heritage sector. Earlier studies using the fluorescence lidar technique has been undertaken at, for example, Parma, Lund and Pisa Cathedral. During the winter 2005 two field studies were performed in Rome, one on parts of the Flavian Amphitheatre Coliseum, and the other on parts of the Lateran Baptistery. The studies were performed from remote and with no need for taking samples. The aim was to identify different materials, different biodeteriogens and other objectives not yet visible for the human eye. Objectives for the project The primary aim of the research project is to analyse the potential of the fluorescence lidar technique in building investigation. Furthermore, to establish a scientific remote-sensing method for surveying and analysing the historical facade that is non-destructive and takes place in-situ. The aim of the fluorescence lidar method is to use point-monitoring and scanning of areas which can provide multispectral images in order to identify different types of stones, their origin, different biodeteriogens and conservation chemicals. A specific aim of the project is to develop the method in comparison with existing documentation methods, to improve the understanding of the built heritage and to provide a basis for new interventions, documentation and maintenance. Methods Fluorescence techniques make it possible to extend the application of fluorescence spectroscopy to the outdoor environment (remote sensing), with sometimes large distances and uncontrollable background light. The ultra-violet laser pulse used in the experiments (usually 355 nm and 308 nm) is directed to the point of interest, exciting atoms and molecules in the material, which then relax emitting fluorescence light. The unique fluorescence spectra from each point taken can then be analysed and identified. By applying a function to the different spectra, each point is assigned a value, and from this a false-colour coded image can be produced, indicating points with different properties, revealing e.g. different materials and earlier treatments. Lateran Baptistery field study The study of the Lateran Baptistery in Rome is a co-operation between Lund University, the Swedish Institute in Rome, CNR-IFAC in Florence, and the research project led by Dr. O. Brandt and Dr. G. Eriksdotter, from the Swedish Institute, the Vatican Museums and the Pontifical Institute of Christian Archaeology, also involving Italian and Swedish archaeology students who has performed a stratigraphic analysis during 2005. The Baptistery, part of the San Giovanni in Lateran church complex, dates back to the fourth hundred-century AC. The analysis from the lidar campaign and the stratigraphic studies are now being cross-examined and the analysis aims to identify brick material and if possible distinguish different building and restoration phases of the baptistery.
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  • Resultat 1-7 av 7

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