Seminar

Material identification of small particles by forward-scattered wave sensing

Speaker: Nobuhiro Moteki, University of Tokyo

When: Wednesday, March 4, 2020, 3:30 p.m. Mountain Time
Location: Room 2A305, DSRC (NOAA Building), 325 Broadway, Boulder
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Abstract:

Suspended particulate matter in the earth's surface environment (i.e., atmosphere, ocean, cryosphere, etc.) is an unknown mixture of unknown materials. In most cases, the particle shape and particle size distribution are also unknown. Quantitative and self-consistent observation of such unknown particles over a vast range of time and space, in manageable costs, is demanded by a lot of environmental science and engineering problems. In this talk, I will show that the forward-scattered wave sensing of individual particles (SPES) with Bayesian data analyses enables the simultaneous determination of complex refractive index, volume-equivalent size distribution, and shape for each of the coexisting particulate materials, provided they are externally mixed. This measurement principle is effective for the particle size range comparable to the laser wavelength. This low-cost generic principle for inline particle analyses will be suitable for both laboratory studies and field observations, possibly after minor customizations (e.g., wavelength) for individual applications.


Nobuhiro Moteki is an Assistant Professor in the Department of Earth and Planetary Sciences at the University of Tokyo. His research has focused on black carbon and aerosol instrument development, with over 60 publications. He will be visiting NOAA during April 2020 - March 2021 with a research fellowship from the JSPS from Joint International Research between NOAA ESRL CSD and the University of Tokyo.