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- Bengtsson, Per Erik
(författare)
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Simultaneous two-dimensional visualization of soot and OH in flames using laser-induced fluorescence
- 1996
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Ingår i: Applied Spectroscopy. - 0003-7028. ; 50:9, s. 1182-1186
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional visualization of soot has been realized in flames with the use of laser-induced fluorescence in C2 from laser-vaporized soot [LIF(C2)LVS]. Soot particles are heated to vaporization temperatures by the absorption of laser radiation. C2 radicals produced by this process are excited at wavelengths around 563 nm through the transition ν′ = 0 d3∏g←ν″ = 1 a3∏u, and the subsequent fluorescence at approximately 516 nm is detected. By frequency-doubling of the laser radiation, wavelengths around 281.5 nm are achieved, which can excite OH radicals to the ν′ = 1 A2Σ+ state from ν″ = 0 X2∏, with subsequent fluorescence at approximately 310 nm. With the use of both these excitation wavelengths, and a Cassegrainian split-mirror telescope as the imaging detection system in front of the charge-coupled device (CCD) camera, simultaneous two-dimensional single-shot images of soot and OH were obtained on a single CCD chip, thus enabling both sooting regions and reaction zones in flames to be monitored.
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| 2. |
- Bood, Joakim, et al.
(författare)
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Knock in spark-ignition engines : End-gas temperature measurements using rotational CARS and detailed kinetic calculations of the autoignition process
- 1997
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
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Konferensbidrag (refereegranskat)abstract
- Cycle-resolved end-gas temperatures were measured using dual-broadband rotational CARS in a single-cylinder spark-ignition engine. Simultaneous cylinder pressure measurements were used as an indicator for knock and as input data to numerical calculations. The chemical processes in the end-gas have been analysed with a detailed kinetic mechanism for mixtures of iso-octane and n-heptane at different Research Octane Numbers (RON'S). The end-gas is modelled as a homogeneous reactor that is compressed or expanded by the piston movement and the flame propagation in the cylinder. The calculated temperatures are in agreement with the temperatures evaluated from CARS measurements. It is found that calculations with different RON'S of the fuel lead to different levels of radical concentrations in the end-gas. The apperance of the first stage of the autoignition process is marginally influenced by the RON, while the ignition delay of the second stage is increased with increasing RON.
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| 3. |
- Bood, Joakim, et al.
(författare)
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Non-intrusive temperature and oxygen concentration measurements in a catalytic combustor using : Rotational coherent anti-stokes raman spectroscopy
- 1999
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Ingår i: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations. - 9780791878590 ; 2
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Konferensbidrag (refereegranskat)abstract
- Rotational CARS (Coherent anti-Stokes Raman Spectroscopy) was used to measure temperature and relative oxygen concentrations in the exhaust gas of a catalytic combustor. This laser technique has the general advantages of such techniques, i.e. possibility of performing in-situ measurements with high spatial and temporal resolution, and non-intrusiveness. Profiles of temperature and oxygen concentrations are presented for a full-load condition, and the measured temperatures are compared with calculated values. Of great importance for the results is the accuracy of the technique, and a sensitivity analysis is performed to test the temperature and oxygen concentration dependence on uncertainties in experimental parameters. It was shown that the accuracy of temperature and oxygen concentration could be improved by fitting the nonresonant susceptibility in the evaluation procedure. The measurements were performed as a project in the European gas turbine program AGATA with the aim to develop a catalytic combustor with ceramic structural components and producing low emissions of pollutants.
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| 4. |
- Bood, Joakim, et al.
(författare)
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Stray light rejection in rotational coherent anti-Stokes Raman spectroscopy by use of a sodium-seeded flame
- 1998
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Ingår i: Applied Optics. - 1559-128X. ; 37:36, s. 8392-8396
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Tidskriftsartikel (refereegranskat)abstract
- A common experimental problem with rotational coherent anti-Stokes Raman spectroscopy (CARS) is undesired spectral interference that is due to stray light from the primary laser beams. Also, for the most developed approach, dual-broadband rotational CARS, practical measurements often suffer from stray light interference from the narrow-band laser, inasmuch as the CARS signal is produced inherently in the spectral vicinity of the narrow-band laser beam. An optical filter does not provide a sufficiently sharp transmission profile, thus leading to signal loss and spectral distortion of the rotational CARS signal. An atomic filter consisting of a sodium-seeded flame is presented here as a solution to the problem, and its usefulness was demonstrated in dual-broadband rotational CARS experiments.
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| 5. |
- Larsson, Per-Erik, et al.
(författare)
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Biologiska effekter i kalkad skog. Årsrapport 1998. Effektuppföljning av Skogsstyrelsens program för kalkning och vitaliseringsgödsling av skogsmark.
- 1999
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Skogsstyrelsens försöksverksamhet med kalkning och vitalisering av skogsmark innehåller ett omfattande program för effektuppföljning. IVL (IVL Svenska Miljöinstitutet AB) i Aneboda har tillsammans med Skogsvårdsstyrelserna huvudansvaret för uppföljningen. Huvuddelen av programmet är inriktat mot effekter på träd, mark och vatten, då kalkning utförts enligt Skogsstyrelsens koncept. Utöver detta basprogram finns även särskilda försök där olika typer av kalk och aska prövas. Resultaten presenteras i årliga rapporter. Tidigare rapporter har behandlat kalkningseffekter på ytvatten och effekter i marken, baserad på markkemiska och markvattenkemiska mätningar. Denna rapport redovisar resultaten från uppföljningsprogrammet för biologiska effekter. Den baseras på undersökningar av bottenfauna, påväxtalger, barrkemi och trädens vitalitet. Studierna är utförda inom Skogsstyrelsens storskaliga försök med skogsmarkskalkning och vitaliseringsgödsling. Rapporten omfattar tidsperioden, eller delar av perioden, 1991 till 1998. Resultaten i sammanfattning är: Bottenfauna. Undersökningen visar att den kalkdos på 3 ton per hektar som använts i försöken inte är tillräcklig för att påverka faunan i kraftigt försurade bäckar under de första sju till åtta åren efter behandling.Någon ökning av antalet individer och taxa eller större biodiversitet har inte kunnat påvisas. Det har heller inte framkommit något som tyder på att faunan har skadats av någon 'kalkchock' eller liknande efter behandlingen
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