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Steven G. Buckley
Department of Mechanical and Aerospace Engineering
University of California, San Diego
Particulate Matter and Gas Composition Measurements
Using Laser-Induced Breakdown Spectroscopy
Design
Abstract
Methods of rapidly measuring gas composition and the composition of
single submicron particles are of great practical interest. For gas
measurement, optical methods such as Raman spectroscopy are quite
useful in understanding fluid mixing, optimizing combustion, and
minimizing emissions. However, when applied to reacting flows, many
existing optical methods are limited by the need for some knowledge of
the reaction progress, as they measure mole fractions of molecular
reactant or product species. Other methods measure condensed-phase
(spray) concentrations before combustion, or flame emission directly,
to infer composition. In this seminar I will discuss the use of
Laser-Induced Breakdown Spectroscopy (LIBS) for direct measurement of
atomic species to determine gas and particle phase composition in
combustion and environmental flows. Atomic emission from a
laser-induced plasma is observed and ratios of elemental lines present
in the spectra can be used to infer composition independent of the
reaction progress in reacting flows, or of individual aerosol
particles. The technique has a spatial resolution on the order of 1
mm, and equivalence ratio can be determined from single-shot spectra,
avoiding time averaging of signals. For particle analysis, detection
limits ranging between 10-200 fg of absolute mass are easily achieved
for many elements. Results of laboratory, engine, and ambient aerosol
measurements will be discussed.
Biosketch
Steven G. Buckley joined the faculty of the Department of Mechanical
and Aerospace Engineering and the Center for Energy Research at UCSD
in July 2003. His research centers on real-time, in-situ combustion
and atmospheric emission measurement techniques, including work on
gas-phase, particulate-phase, and bio-aerosol measurements.
Dr. Buckley's research group also works on fundamental combustion
issues and has developed novel optical sensors for structural
monitoring. In 2001 Buckley won both the ONR Young Investigator Award
and the NSF Early Career Development Award. Prior to his current
position, Dr. Buckley was an Assistant Professor at the University of
Maryland in College Park (1999 - 2003) and held both postdoctoral and
technical staff positions at Sandia National Laboratories in
Livermore, CA (1995-1999). Prof. Buckley is a Past Chair of the
Environmental Engineering Division (EED) of the ASME, and currently
serves ASME in several capacities, including advisor to the ASME
student section at UCSD. He is a member of the Combustion Institute,
the Air and Waste Management Association, the American Association of
Aerosol Research, and the Society for Applied Spectroscopy.
Wednesday, October 13, 2004
Bourns Hall, Room A265
10:10 a.m.-11:00 a.m.
(Refreshments will be served at 10:00 a.m.)
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