Various methods have been used to measure the particle size and number density of ultrafine bubbles generated by the ultrafine bubble generator, ultrafineGALF. The presence of particles with diameters of about 100 to 200 nm was indicated by every method that we used before. However, absolute identification of these as ultrafine bubbles rather than some other type of particle was not possible because conventional measurement methods using light generated by a laser and scattered by particles do not distinguish dust particles from bubbles. The present series of experiments, using the resonant mass measurement method, was the first to succeed in clearly distinguishing ultrafine bubbles from other particles. This was due to the use of the resonant mass measurement method, which is capable of distinguishing positively buoyant particles (bubbles) from negatively buoyant particles. In addition, the results from the resonant mass measurement method were compared, in terms of particle size distribution, with this from the particle tracking analysis method, which uses a different measurement principle. The particle size distributions yielded by both methods showed a moderate correlation between the number density results obtained by each.

Date Published: 6 August 2014
PDF: 5 pages
Proc. SPIE 9232, International Conference on Optical Particle Characterization (OPC 2014), 92320S (6 August 2014); doi: 10.1117/12.2064811

Published in SPIE Proceedings Vol. 9232:
International Conference on Optical Particle Characterization (OPC 2014)
Nobuhiro Aya; Norihiko Iki; Tsutomu Shimura; Tomohiro Shirai, Editor(s)