scholarly journals Mass transfer effects in hygroscopic measurements of aerosol particles

2005 ◽  
Vol 5 (10) ◽  
pp. 2703-2712 ◽  
Author(s):  
M. N. Chan ◽  
C. K. Chan
Keyword(s):  
Mass Transfer ◽  
Residence Time ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Literature Survey ◽  
Atmospheric Particles ◽  
Transfer Effects ◽  
Differential Mobility ◽  
Scattering Coefficients ◽  
Important Concern

Abstract. The tandem differential mobility analyzer (TDMA) has been widely utilized to measure the hygroscopicity of laboratory-generated and atmospheric submicrometer particles. An important concern in investigating the hygroscopicity of the particles is if the particles have attained equilibrium state in the measurements. We present a literature survey to investigate the mass transfer effects in hygroscopicity measurements. In most TDMA studies, a residence time in the order of seconds is used for humidification (or dehumidification). NaCl and (NH4)2SO4 particles are usually used to verify the equilibrium measurements during this residence time, which is presumed to be sufficient for other particles. There have been observations that not all types of submicrometer particles, including atmospheric particles, attain their equilibrium sizes within this time scale. We recommend that experimentation with different residence times be conducted and that the residence time should be explicitly stated in future TDMA measurements. Mass transfer effects may also exist in the measurements of other properties related to the water uptake of atmospheric particles such as relative humidity dependent light scattering coefficients and cloud condensation nuclei activity.

scholarly journals Mass transfer effects in hygroscopic measurements of aerosol particles

2005 ◽  
Vol 5 (3) ◽  
pp. 4057-4082 ◽  
Author(s):  
M. N. Chan ◽  
C. K. Chan
Keyword(s):  
Mass Transfer ◽  
Residence Time ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Literature Survey ◽  
Atmospheric Particles ◽  
Transfer Effects ◽  
Differential Mobility ◽  
Scattering Coefficients ◽  
Important Concern

Abstract. The tandem differential mobility analyzer (TDMA) has been widely utilized to measure the hygroscopicity of laboratory-generated and atmospheric submicrometer particles. An important concern in investigating the hygroscopicity of the particles is if the particles have attained equilibrium state in the measurements. We present a literature survey to investigate the mass transfer effects in hygroscopicity measurements. In most TDMA studies, a residence time in the order of seconds is used for humidification (or dehumidification). NaCl and (NH4)2SO4 particles are usually used to verify the equilibrium measurements during this residence time, which is presumed to be sufficient for other particles. There have been observations that not all types of submicrometer particles, including atmospheric particles, attain their equilibrium sizes within this time scale. We recommend that experimentation with different residence times be conducted and that the residence time should be explicitly stated in future TDMA measurements. Mass transfer effects may also exist in the measurements of other properties related to the water uptake of atmospheric particles such as relative humidity dependent light scattering coefficients and cloud condensation nuclei activity.

A Microfluidic Device for Studying Mass Transfer Effects in Biomolecular Analysis

2002 ◽  
Author(s):  
Min Yue ◽  
Katherine Dunphy ◽  
Jerry Jenkins ◽  
Christopher Dames ◽  
Guanghua Wu ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Microfluidic Device ◽  
Transfer Effects ◽  
Biomolecular Analysis

Numerical modeling of large-scale bubble plumes accounting for mass transfer effects

2002 ◽  
Vol 28 (11) ◽  
pp. 1763-1785 ◽  
Author(s):  
Gustavo C. Buscaglia ◽  
Fabián A. Bombardelli ◽  
Marcelo H. Garcı́a
Keyword(s):  
Mass Transfer ◽  
Numerical Modeling ◽  
Large Scale ◽  
Transfer Effects ◽  
Bubble Plumes

scholarly journals Calibration of LACIS as a CCN detector and its use in measuring activation and hygroscopic growth of atmospheric aerosol particles

2006 ◽  
Vol 6 (12) ◽  
pp. 4519-4527 ◽  
Author(s):  
H. Wex ◽  
A. Kiselev ◽  
M. Ziese ◽  
F. Stratmann
Keyword(s):  
Sodium Chloride ◽  
Wall Temperature ◽  
Atmospheric Aerosol ◽  
Volume Fraction ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Urban Aerosol ◽  
Hygroscopic Growth ◽  
Atmospheric Aerosol Particles ◽  
Droplet Activation

Abstract. A calibration for LACIS (Leipzig Aerosol Cloud Interaction Simulator) for its use as a CCN (cloud condensation nuclei) detector has been developed. For this purpose, sodium chloride and ammonium sulfate particles of known sizes were generated and their grown sizes were detected at the LACIS outlet. From these signals, the effective critical super-saturation was derived as a function of the LACIS wall temperature. With this, LACIS is calibrated for its use as a CCN detector. The applicability of LACIS for measurements of the droplet activation, and also of the hygroscopic growth of atmospheric aerosol particles was tested. The activation of the urban aerosol particles used in the measurements was found to occur at a critical super-saturation of 0.46% for particles with a dry diameter of 75 nm, and at 0.42% for 85 nm, respectively. Hygroscopic growth was measured for atmospheric aerosol particles with dry diameters of 150, 300 and 350 nm at relative humidities of 98 and 99%, and it was found that the larger dry particles contained a larger soluble volume fraction of about 0.85, compared to about 0.6 for the 150 nm particles.

Sign in / Sign up

Export Citation Format

Share Document