A New Dual-type DMA for the Measurement of Nanoparticles from Engines. Kazuo Takeuchi 1,2) , Junsuke Yabumoto 1,2) , Yoshiki Okada 1,2) 1) Wyckoff Co., Ltd., 2) RIKEN Akio Kibayashi 3) 3) Shimadzu Co. Terunao Kawai 4) and Yuichi Goto 4) 4) NTSEL.
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of Nanoparticles from Engines
Kazuo Takeuchi1,2), Junsuke Yabumoto1,2), Yoshiki Okada1,2)
1) Wyckoff Co., Ltd., 2) RIKEN
3) Shimadzu Co.
Terunao Kawai4) and Yuichi Goto4)
1. Measurement of Gas-borne Nanoparticles
2. Calibration of Size Measurement
3. Difficulties in Conventional DMAs
4. Dual-type DMA as a Solution
8th ETH CONF.
Nanoparticles: 1 nm < dp < 300 nm
Differential Mobility Analyzer (DMA)
Electrical mobility of particles
Size distribution of particles
Dp: Particle diameter
Cc: Cunningham correction factor
m: Gas viscosity
np: Number of elementary charges on a particle
Size-selection of nanoparticles using DMA
Problem for Conventional DMAs in Automobile Exhaust Measurement
Typically, conventional DMAs need to scan the voltage for 2 minutes
Cannot cope with the quick transient behaviors in automobile exhaust
Typical particle size distribution of nanoparticles in engine exhaust
DMA with a multi-channel detector
Image reproduced from
D.B. Kittelson and W. Watts,
Third Joint ESF-NSF Symposium Abs.,
Dublin, Sept. 6 (2000).
Sheath gas inlet #1
Mobility analyzer #1
Aerosol gas inlet
Aerosol gas inlet
Sheath gas inlet #2
Mobility analyzer #2
Excess gas outlet #1
Excess gas outlet #2
Generation of model nanoparticles with bimodal size distribution
Model nanoparticles corresponding to nuclei mode
Model nanoparticles corresponding to accumulation mode
Number density (#/cc)
Scanning Mode Measurement of Model Nanoparticles
Transient Mode Measurement of Model Nanoparticles distribution
Concluding Remarks distribution
Acknowledgement: We would like to thank JRTT for financial support. We would also like to thank Dr. Montajir and the scientists and technicians of NTSEL, Wyckoff, RIKEN and Shimadzu for their technical support and advice.