Afhandlingen, der har titlen "Photoacoustic Spectroscopy for Residual Oil Contamination Monitoring Using Near Infrared Lasers", er lavet i samarbejde med PAJ Systemteknik A/S.
Invitation to PhD Thesis Defence
Feng Yuyang:
Title: Photoacoustic Spectroscopy for Residual Oil Contamination Monitoring Using Near Infrared Lasers
The Mads Clausen Institute
University of Southern Denmark
PAJ Systemteknik A/S
Friday 9 May 2008
10:00 am -13:00 pm
Room U101 at Alsion - Sonderborg
University of Southern Denmark
Abstract: NIR laser based PA (Photoacoustic) is an emerging technology and recognized technique with great potential for industrial applications in contamination detections. Laser intensity or wavelength modulations corresponding to an absorption line of the contamination species excite weak acoustic waves in gas media. Using high sensitivity condenser microphones as detectors, PA arrangement can be constructed with compact size and good sensitivity for vapour detection.
The goal of this research aims at discovering and developing practical instrumental principles for Residue Oil Contamination (OC) detection with compressed air, to be used an on-line instrument approach to substitute existing analytical chemistry procedures, which are regulated by the ISO8573-2/5 standards. NIR-PA techniques have been adopted in this research. General investigations with differential PA resonator, TDLS (Tunable Diode Laser Spectroscopy), WMS (Wavelength Modulation Spectroscopy)-PA were carried out. Detailed PA FEM simulation and theories of PA operations have been presented. A stand alone TDLS-PA instrument prototype has been constructed. Moreover, a new ink-jet based oil contamination vapour/aerosol calibrator has been invented. A Labview controlled compressed air test-rig setup with flow capacity up to 4000~L/min has been designed and constructed. Finally, all sub-systems have been integrated. Some trial attempts for quantitative characterization of n-heptane and machine oil contaminations with compressed air test rig have been succeed. The constructed PA instrument demonstrated ambient noise immunity (acoustic dominated) in harsh industrial environment. As a conclusion, the NIR-PA can be a good technology for achieving OC on-line instrument and contamination sensor platform.
Laser diode based PA and OC test facilities have been the research outcome for the new science and device suggestions to the commercial product OC sensor.
Keywords: Photoacoustic spectroscopy, TDLS, residue oil contamination, ISO8573, NIR-PA, ink-jet based vapour/aerosol calibrator, vapour sensing.
09.05.2008
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