| 1. |
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| 2. |
- Bengtsson, Magnus, et al.
(författare)
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Lidar fluorescence measurements of algal growth on electrical insulators
- 2003
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Ingår i: 2003 Conference on Lasers and Electro-Optics Europe (CLEO/Europe 2003) (IEEE Cat. No.03TH8666). - 0780377346 ; , s. 473-473
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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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| 3. |
- Bäckström, Erica, et al.
(författare)
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Development of a Novel Lung Slice Methodology for Profiling of Inhaled Compounds
- 2016
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0022-3549 .- 1520-6017. ; 105:2, s. 838-845
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Tidskriftsartikel (refereegranskat)abstract
- The challenge of defining the concentration of unbound drug at the lung target site after inhalation limits the possibility to optimize target exposure by compound design. In this study, a novel rat lung slice methodology has been developed and applied to study drug uptake in lung tissue, and the mechanisms by which this occurs. Freshly prepared lung slices (500 μm) from drug-naive rats were incubated with drugs followed by determination of the unbound drug volume of distribution in lung (Vu,lung), as the total concentration of drug in slices divided by the buffer (unbound) concentration. Vu,lung determined for a set of inhaled drug compounds ranged from 2.21 mL/g for salbutamol to 2970 mL/g for dibasic compound A. Co-incubation with monensin, a modulator of lysosomal pH, resulted in inhibition of tissue uptake of basic propranolol to 13%, indicating extensive lysosomal trapping. Partitioning into cells was particularly high for the cation MPP+ and the dibasic compound A, likely because of the carrier-mediated transport and lysosomal trapping. The results show that different factors are important for tissue uptake and the presented method can be used for profiling of inhaled compounds, leading to a greater understanding of distribution and exposure of drug in the lung.
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| 4. |
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| 5. |
- Dernfalk, Andreas, 1975, et al.
(författare)
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Laser-induced fluorescence spectroscopy for detection of biological contamination on composite insulators
- 2003
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Ingår i: In Proc. 13th International Symposium on High Voltage Engineering, Delft, Netherlands.
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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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| 6. |
- Fernstål, Lotta, et al.
(författare)
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Inledning : Om Sverige i tiden
- 2015
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Ingår i: Sverige i tiden. - Stockholm : Historiska museets förlag. - 9789189176591 ; , s. 9-15
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Grönlund, Rasmus, et al.
(författare)
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Elemental mercury emissions from chlor-alkali plants measured by lidar techniques
- 2005
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 39:39, s. 7474-7480
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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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| 8. |
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| 9. |
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| 10. |
- Hellström, Petter, et al.
(författare)
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Krigarkonungen och kåldolmarna
- 2013
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Annan publikation (populärvet., debatt m.m.)abstract
- Karl XII har gjorts till symbol för nationalism, rasism och nazism, men hans tid i det muslimska Turkiet vittnar snarare om kulturell öppenhet. Ett resultat av kungens turkiska allians var den svenska kåldolmen.
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| 11. |
- Lognoli, D, et al.
(författare)
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Fluorescence lidar imaging of the cathedral and baptistery of Parma
- 2003
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171. ; 76:4, s. 457-465
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Tidskriftsartikel (refereegranskat)abstract
- Extensive fluorescence multispectral imaging of the cathedral and baptistery of Parma, Italy, is reported and discussed. In particular, the first fluorescence imaging data from protection-treated stony materials were recorded. Fluorescence spectra were taken with a mobile lidar system scanning the monument surfaces with a frequency-tripled Nd:YAG laser beam from a distance of about 80 m. For each pixel of the area investigated, a high-spectral-resolution spectrum in the full visible range was acquired. The principal-component analysis technique was used to obtain thematic maps that outlined areas subject to protective treatment and biological growth, and other features, such as different types of stones and decoration pigments.
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| 12. |
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Saito, Y, et al.
(författare)
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Possibility of hard-target lidar detection of a biogenic volatile organic compound, alpha-pinene gas, over forest areas
- 2001
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Ingår i: Applied Optics. - 2155-3165. ; 40:21, s. 3572-3574
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Tidskriftsartikel (refereegranskat)abstract
- The absorption spectrum of alpha -pinene gas, a biogenic volatile organic compound, was directly measured with a pulsed mid-infrared laser. The maximum absorption wavelength was found to be similar to3.42 mum, and an absorption cross section of 4.8 x 10(-23) m(2) molec(-1) was obtained. A simple theoretical calculation with the measured spectral data showed that several hundreds of parts in 10(12) (ppt) of a-pinene gas in forest-mountain areas over a range of similar to 10 km were detectable by a long-path-averaged hard-target absorption lidar. Requirements for system development were also discussed. (C) 2001 Optical Society of America.
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| 17. |
- Sandsten, J, et al.
(författare)
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Real-time gas-correlation imaging employing thermal background radiation
- 2000
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Ingår i: Optics Express. - 1094-4087. ; 6:4, s. 92-103
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Tidskriftsartikel (refereegranskat)abstract
- Real-time imaging of gas leaks was demonstrated using an IR camera employing outdoor thermal background radiation. Ammonia, ethylene and methane detection was demonstrated in the spectral region 7-13 mu m. Imaging was accomplished using an optical filter and a gas-correlation cell matching the absorption band of the gas. When two gases, such as ammonia and ethylene, are absorbing in the same wavelength region it is possible to isolate one for display by using gas-correlation multispectral imaging. Results from a field test on a leaking gas tanker are presented as QuickTime movies. A detection limit of 200 ppm x meter for ammonia was accomplished in this setup when the temperature difference between the background and the gas was 18 K and the frame rate was 15 Hz. (C) 2000 Optical Society of America.
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| 18. |
- Sjögren, Erik, et al.
(författare)
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Optimized Experimental Design for the Estimation of Enzyme Kinetic Parameters : An Experimental Evaluation
- 2012
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Ingår i: Drug Metabolism And Disposition. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0090-9556 .- 1521-009X. ; 40:12, s. 2273-2279
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Tidskriftsartikel (refereegranskat)abstract
- A set of compounds (n = 30), including traditional cytochrome P450 substrates and compounds from AstraZeneca's compound library, was used in an experimental evaluation of an optimal design approach (ODA) for the estimation of enzyme kinetic parameters (CLint, V-max, and K-m). A depletion method previously shown to provide reliable results, the multiple depletion curves method (MDCM), was used as reference. Experiments were conducted with human liver microsomes, and samples were analyzed using liquid chromatography-tandem mass spectrometry. CLint estimated with the ODA were in >90% of the cases within a 2-fold difference compared with MDCM estimates. In addition, good agreement was generally seen for V-max and K-m estimates between the two methods as >80% of the estimates were within or almost within a 2-fold difference. The variability in V-max and K-m estimates were generally higher than for CLint estimates. In addition, decreased substrate turnover considerably increased the variability in V-max and Km estimates, whereas only a modest increase was observed for CLint estimates. The experimental design of using multiple starting concentrations for the estimation of enzyme kinetics was shown to be appropriate even when there was a limitation to the number of samples. The method allowed for good estimates of CLint and also for V-max and K-m in many cases. Hence, this approach is a good alternative for the estimation of enzyme kinetic parameters, especially if enzyme saturation and an assessment of a potential risk for nonlinear metabolism are of interest.
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| 19. |
- Sjöholm, Mikael, et al.
(författare)
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Atomic mercury flux monitoring using an optical parametric oscillator based lidar system
- 2004
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Ingår i: Optics Express. - 1094-4087. ; 12:4, s. 551-556
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Tidskriftsartikel (refereegranskat)abstract
- A newly developed optical parametric oscillator (OPO) based differential absorption lidar (DIAL) system has been applied to the monitoring of atomic mercury emissions at several chlor-alkali plants in Europe. The versatility of the system is illustrated by measured time series of mercury flux and movies of vertical and horizontal concentration distributions, which yield important input parameters for the environmental community. Long term measurements of the resonance absorption of mercury at 253.65 nm poses special demands, i.e. long term stability, on the light source that often have been hard to fulfill, in different respects, for standard OPO and dye laser based systems. Here, approaches to meet these demands are presented.
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| 20. |
- Sjöholm, Mikael, et al.
(författare)
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Optical parametric oscillator based lidar system applied to atomic mercury monitoring
- 2003
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Ingår i: 2003 Conference on Lasers and Electro-Optics Europe (CLEO/Europe 2003) (IEEE Cat. No.03TH8666). - 0780377346 ; , s. 471-471
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Konferensbidrag (refereegranskat)abstract
- Field measurements of mercury emissions has been performed by using a mobile lidar system. In this system an Nd:YAG-pumped OPO (Optical Parametric Oscillator) laser system is employed to generate a narrow band (better than 0.2 cm-1) UV beam at the mercury resonance absorption line at 253.65 nm. An inter-comparison of the lidar system and two different point monitoring systems has been performed showing excellent agreement between the instruments
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| 21. |
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| 22. |
- Wangberg, I, et al.
(författare)
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Atmospheric mercury near a chlor-alkali plant in Sweden
- 2003
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Ingår i: Science of the Total Environment. - 1879-1026. ; 304:1-3, s. 29-41
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric mercury species/fractions were measured near a chlor-alkali plant in Sweden during August 28 to September 4, 2001. The concentration of total gaseous mercury in the plume from the plant was measured using TEKRAN and GARDIS instruments. Gaseous elemental mercury was measured using a light detection and ranging (LIDAR) technique. From vertical LIDAR sweeps through the plume from the chlor-alkali plant mercury emission rates could be calculated. The concentrations of reactive gaseous mercury (RGM) in the plume and also inside the cell house were measured using annular KCl coated denuders. The RGM emission constitutes 0.5-1.0% of the total mercury emitted from the plant. The mercury concentration adsorbed on particles was measured as well as the mercury flux from soil. The data presented also include an intercomparison showing an excellent agreement between TEKRAN/GARDIS and LIDAR gaseous mercury measurements. (C) 2003 Elsevier Science B.V. All rights reserved.
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| 23. |
- Weibring, Petter, et al.
(författare)
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Development and testing of a frequency-agile optical parametric oscillator system for differential absorption lidar
- 2003
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 74:10, s. 4478-4484
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Tidskriftsartikel (refereegranskat)abstract
- An all-solid-state fast-tuning lidar transmitter for range- and temporally resolved atmospheric gas concentration measurements has been developed and thoroughly tested. The instrument is based on a commercial optical parametric oscillator (OPO) laser system, which has been redesigned with piezoelectric transducers mounted on the wavelength-tuning mirror and on the crystal angle tuning element in the OPO. Piezoelectric transducers similarly control a frequency-mixing stage and doubling stage, which have been incorporated to extend system capabilities to the mid-IR and UV regions. The construction allows the system to be tuned to any wavelength, in any order, in the range of the piezoelectric transducers on a shot-to-shot basis. This extends the measurement capabilities far beyond the two-wavelength differential absorption lidar method and enables simultaneous measurements of several gases. The system performance in terms of wavelength, linewidth, and power stability is monitored in real time by an etalon-based wave meter and gas cells. The tests showed that the system was able to produce radiation in the 220-4300-nm-wavelength region, with an average linewidth better than 0.2 cm(-1) and a shot-to-shot tunability up to 160 cm(-1) within 20 ms. The utility of real-time linewidth and wavelength measurements is demonstrated by the ability to identify occasional poor quality laser shots and disregard these measurements. Also, absorption cell measurements of methane and mercury demonstrate the performance in obtaining stable wavelength and linewidth during rapid scans in the mid-IR and UV regions.
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| 24. |
- Weibring, Petter, et al.
(författare)
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Fluorescence lidar imaging of historical monuments
- 2001
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Ingår i: Applied Optics. - 2155-3165. ; 40:33, s. 6111-6120
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Tidskriftsartikel (refereegranskat)abstract
- What is believed to be the first fluorescence imaging of the facades of a historical building, which was accomplished with a scanning fluorescence lidar system, is reported. The mobile system was placed at a distance of similar to 60 m from the medieval Lund Cathedral (Sweden), and a 355-nm pulsed laser beam was swept over the stone facades row by row while spectrally resolved fluorescence signals of each measurement point were recorded. By multispectral image processing, either by formation of simple spectral-band ratios or by use of multivariate techniques, areas with different spectral signatures were classified. In particular, biological growth was observed and different stone types were distinguished. The technique can yield data for use in facade status assessment and restoration planning. (C) 2001 Optical Society of America.
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| 25. |
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| 26. |
- Weibring, Petter, et al.
(författare)
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Monitoring of volcanic sulphur dioxide emissions using differential absorption lidar (DIAL), differential optical absorption spectroscopy (DOAS), and correlation spectroscopy (COSPEC)
- 1998
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171. ; 67:4, s. 419-426
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Tidskriftsartikel (refereegranskat)abstract
- The total fluxes of sulphur dioxide from the Italian volcanoes Etna, Stromboli, and Vulcano were studied using optical remote sensing techniques in three shipborne field experiments (1992, 1994, and 1997). The main purpose of the experiments was to compare active (laser) techniques with passive monitoring. Differential absorption lidar (DIAL) measurements were implemented by placing the Swedish mobile lidar system on board the Italian research vessel Urania, sailing under the volcanic plumes. Simultaneously, the passive differential optical absorption spectroscopy (DOAS) technique was used for assessing the total overhead gas burden. Finally, correlation spectroscopy (COSPEC) was also implemented in one of the campaigns. Differences in integrated gas column assessment are expected and observed, mostly connected to complex scattering conditions influencing the passive measurements. Since such measurements are much employed in routine volcanic monitoring it is of great interest to model and provide corrections to the raw data obtained. Lidar measurements proved to be quite useful for this purpose. By combining the integrated gas concentration over the plume cross section with wind velocity data, SO2 fluxes of the order of 1000, 100, and 10 tonnes/day were measured for Mt. Etna, Stromboli, and Vulcano, respectively.
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| 27. |
- Weibring, Petter, et al.
(författare)
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Multi-component chemical analysis of gas mixtures using a continuously tuneable lidar system
- 2004
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 79:4, s. 525-530
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Tidskriftsartikel (refereegranskat)abstract
- Differential absorption lidar (DIAL) measurements are usually made on single compounds by alternately switching the wavelength between on and off a resonance line. The selection of more than two wavelengths is a mathematical necessity for simultaneous measurement of multiple species or for resolving interference effects between a compound of interest and a background gas such as water vapour or carbon dioxide. This is especially true in the mid-IR region, where many hydrocarbon compounds have important spectral features. We present a method for remote measurement of gas mixtures in the mid-IR region based on a newly developed fast-switching, frequency-agile optical parametric oscillator lidar transmitter. A multivariate statistical procedure has also been applied for this system, which combines a genetic algorithm for wavelength selection with a partial least squares method for identifying individual compounds from their combined absorption spectrum. A calibration transfer is performed for compounds of interest using reference spectra from an absorption spectra database. Both indoor absorption cell measurements and outdoor remote range resolved measurements of hydrocarbon mixtures were performed to explore the performance of the method.
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| 28. |
- Weibring, Petter, et al.
(författare)
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Optical monitoring of volcanic sulphur dioxide emissions - comparison between four different remote-sensing spectroscopic techniques
- 2002
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Ingår i: Optics and Lasers in Engineering. - 0143-8166. ; 37:2-3, s. 267-284
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Tidskriftsartikel (refereegranskat)abstract
- The emissions of sulphur dioxide from the Italian volcanoes Mt. Etna and Stromboli were studied in ship-borne underpasses of their plumes. Four different optical spectroscopy techniques were used and inter-compared. All techniques utilise the absorption signature of the gas in the wavelength region of around 300 nm. A differential absorption lidar was employed in active gas concentration assessment. In parallel, a differential optical absorption spectroscopy system (DOAS) provided spectrally resolved absorption spectra, In one configuration the DOAS used a vertically looking telescope and the absorption of the skylight was studied, while a different DOAS implementation utilised the sun disc as the light source in slant-angle, long-path absorption measurements. Parallel measurements with the customary correlation spectroscopy method were also performed. Path length Monte Carlo simulations of the down-welling radiation through the volcanic plume at different sun altitude and azimuth angles have been performed taking into account also the effects of other geometric parameters as the plume height and extension. The results are discussed with special emphasis on systematic effects due to scattering.
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| 29. |
- Weibring, Petter, et al.
(författare)
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Remote analysis of gas mixtures using an optical parametric oscillator based lidar system
- 2003
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Ingår i: 2003 Conference on Lasers and Electro-Optics Europe (CLEO/Europe 2003) (IEEE Cat. No.03TH8666). - 0780377346 ; , s. 472-472
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Konferensbidrag (refereegranskat)abstract
- A scheme for lidar measurements of multicomponent gas mixtures in the mid-IR region using a newly developed fast-switching, frequency-agile optical parametric oscillator (OPO) system combined with multivariate statistical methods has been implemented and tested. The scheme adopted was able to predict the composition of the remote hydrocarbon gas mixture within the uncertainty of the pre-determined gas composition
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| 30. |
- Weibring, Petter, et al.
(författare)
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Remote monitoring of industrial emissions by combination of lidar and plume velocity measurements
- 1998
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171. ; 66:3, s. 383-388
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Tidskriftsartikel (refereegranskat)abstract
- We describe a new method for gas flux measurements that is a combination of differential absorption lidar (DIAL) and wind videography. The wind speed was measured by an imaging method that calculates the horizontal displacement of the plume with cross-correlation techniques. High spatial and temporal resolution is achieved with histogram equalization and window-filtering techniques. Simultaneous measurements of the distance, the direction of the plume and the integrated concentration were provided through the lidar measurements. Alternative methods of measuring the wind speed at different heights have been used to validate the precision and accuracy of the new method for different geometrical configuration. An example of remote mote SO2 flux measurements from a pulp and paper mill is presented, which shows a very good correlation with in situ measurements taken at the source.
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| 31. |
- Weibring, Petter, et al.
(författare)
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Versatile mobile lidar system for environmental monitoring
- 2003
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Ingår i: Applied Optics. - 2155-3165. ; 42:18, s. 3583-3594
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Tidskriftsartikel (refereegranskat)abstract
- A mobile lidar (light detection and ranging) system for environmental monitoring is described. The optical and electronic systems are housed in a truck with a retractable rooftop transmission and receiving mirror, connected to a 40-cm-diameter vertically looking telescope. Two injection-seeded Nd:YAG lasers are employed in connection with an optical parametric oscillator-optical parametric amplification transmitter, allowing deep-UV to mid-IR wavelengths to be generated. Fast switching that employs piezoelectric drivers allows multiwavelength differential absorption lidar for simultaneous measurements of several spectrally overlapping atmospheric species. The system can also be used in an imaging multispectral laser-induced fluorescence mode on solid targets. Advanced LabVIEW computer control and multivariate data processing render the system versatile for a multitude of measuring tasks. We illustrate the monitoring of industrial atmospheric mercury and hydrocarbon emissions, volcanic sulfur dioxide plume mapping, fluorescence lidar probing of seawater, and multispectral fluorescence imaging of the facades of a historical monument. (C) 2003 Optical Society of America.
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