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- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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- Milton, M. J. T, et al.
(författare)
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Raman-shifted laser sources suitable for differential-absorption lidar measurements of ozone in the troposphere
- 1998
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171. ; 66:1, s. 105-113
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Tidskriftsartikel (refereegranskat)abstract
- Measurements have been performed at eight laboratories on Raman-shifted radiation from frequency-quadrupled Nd:YAG and KrF lasers. Each of these sources is a possible candidate for making differential-absorption lidar measurements of ozone in the free troposphere. The spectral purity, efficiency and divergence of the different sources are compared and explained using a simplified model of the Raman interaction. Particular attention has been given to the use of buffer gases to optimize the Raman gain and divergence. The experimental results show that the operating conditions required to optimize the output energy of each of these types of laser source can be quite different. In the case of the KrF laser, it has been shown that high energies can be generated at low active gas pressures, and that increasing the pressure increases the beam quality, but decreases the energy.
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5. |
- Liljelind, I, et al.
(författare)
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Exposure assessment of monoterpenes and styrene : A comparison of air sampling and biomonitoring
- 2003
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Ingår i: Occupational and Environmental Medicine. - : BMJ. - 1351-0711 .- 1470-7926. ; 60:8, s. 599-603
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Tidskriftsartikel (refereegranskat)abstract
- Background: Within- and between-worker variance components have seldom been reported for both environmental and biological data collected from the same persons. Aims: To estimate these variance components and their ratio for air contaminants and urinary metabolites in two different work environments and to predict the attenuation of exposure-response relationships based on these measures. Methods: Parallel measurements of air and urine were performed among workers exposed to monoterpenes in sawmills (urinary metabolite: verbenol) and styrene in reinforced plastics factories (urinary metabolite: mandelic acid). Results: Among the sawmill workers, variance components of the air and urinary verbenol results were similar, for the reinforced plastics workers the estimated between-worker variance component was greater for styrene in air than mandelic acid in urine. This suggests that attenuation bias would be about equal if air or biological monitoring were employed for monoterpene exposures, but would be greater if urinary mandelic acid were used instead of airborne styrene in an investigation of styrene exposure. Conclusions: Personal air samplers provide data with similar or superior quality to urinary metabolites as measures of exposure to these monoterpenes in sawmills and styrene in reinforced plastics factories.
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7. |
- Sunesson, A-L, et al.
(författare)
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Multivariate evaluation of VOCs in buildings where people with non-specific building-related symptoms perceive health problems and in buildings where they do not.
- 2006
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Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 16:5, s. 383-391
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Tidskriftsartikel (refereegranskat)abstract
- Volatile organic compounds (VOCs) were sampled in buildings where people with non-specific building-related symptoms perceive health problems and in buildings where they do not. In total, nine persons and 34 buildings were included in the study. The obtained VOC data was evaluated using multivariate methods, to investigate possible systematic differences in air quality of 'problem' and 'non-problem' buildings. All individual compounds were included as variables in a multivariate partial least squares (PLS) data analysis. 'Problem' and 'non-problem' buildings separated into two distinct groups, showing that air samples of the two groups of building were chemically different. PRACTICAL IMPLICATIONS: The study showed that there was an identifiable systematic difference in the collected VOC data between buildings causing and not causing problems for people with non-specific building-related symptoms (also called sick building syndrome, SBS). This is an important indication that even such volatile organic compounds that can be sampled by commonly used adsorbents are of importance for the presence of such symptoms. By coordination of procedures for sampling and analysis of VOCs in buildings between laboratories, to get large datasets and more general models, the method can become a useful diagnostic measure in evaluating indoor air and to identify chemical compounds and sources that contribute to SBS problems.
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8. |
- Sunesson, A, et al.
(författare)
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Laser Triggering of Electric Breakdown In Liquids
- 1994
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Ingår i: IEEE Transactions on Dielectrics and Electrical Insulation. - : Institute of Electrical and Electronics Engineers (IEEE). - 1070-9878. ; 1:4, s. 680-691
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Tidskriftsartikel (refereegranskat)abstract
- Electric breakdown in semihomogeneous geometries has been studied in n-hexane and transformer oil using a laser triggering method for fields far below the spontaneous breakdown field. The method uses a laser-produced plasma to initiate the breakdown. Strong self focusing in the liquids was limited by increasing the numerical aperture of the laser beam to > 0.20 prior to focusing. Electrical breakdown could be triggered at fields as low as 50 kV/cm in transformer oil and 25 kV/cm for n-hexane. The time lags are between 30 and 200 mus, depending on voltage, liquid, and gap size. Current and light emission measurements of the prebreakdown phenomena are presented and a model for the triggering process is proposed.
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