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Experimental determination of the steady-state charging probabilities and particle size conservation in non-radioactive and radioactive bipolar aerosol chargers in the size range of 5-40 nm.

Kallinger P, Szymanski WW - J Nanopart Res (2015)

Bottom Line: For particular experimental conditions, some deviations from the chosen theoretical model were found for all chargers.For very small particle sizes, the AC-corona charger showed particle losses at low flow rates and did not reach steady-state charge equilibrium at high flow rates.Practically, excellent particle size conservation was found for all three chargers.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.

ABSTRACT

Three bipolar aerosol chargers, an AC-corona (Electrical Ionizer 1090, MSP Corp.), a soft X-ray (Advanced Aerosol Neutralizer 3087, TSI Inc.), and an α-radiation-based (241)Am charger (tapcon & analysesysteme), were investigated on their charging performance of airborne nanoparticles. The charging probabilities for negatively and positively charged particles and the particle size conservation were measured in the diameter range of 5-40 nm using sucrose nanoparticles. Chargers were operated under various flow conditions in the range of 0.6-5.0 liters per minute. For particular experimental conditions, some deviations from the chosen theoretical model were found for all chargers. For very small particle sizes, the AC-corona charger showed particle losses at low flow rates and did not reach steady-state charge equilibrium at high flow rates. However, for all chargers, operating conditions were identified where the bipolar charge equilibrium was achieved. Practically, excellent particle size conservation was found for all three chargers.

No MeSH data available.


Schematic of the experimental setup for the charging probability and particle size conservation measurements
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Related In: Results  -  Collection


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Fig1: Schematic of the experimental setup for the charging probability and particle size conservation measurements

Mentions: The size-dependent steady-state charging probability of the different chargers was measured by means of a tandem DMA setup with the charger of interest placed in between of the two DMAs (Fig. 1). Both of the DMAs used in this study were custom built (according to our specifications by tapcon & analysesysteme, Salzburg, Austria; Kallinger et al. 2013), hydro-mechanically identical and operating at the same polarity. In this setup, the fact was used that the particles exiting a DMA are both monomobile (i.e. of the same electrical mobility) and all of them are unipolar charged. With the investigated charger turned off, the particles remained in their state of charge, and therefore the total number-concentration at the inlet of DMA 2 could be measured with DMA 2 and CPC 2. With the charger turned on, only the number-concentration of the charged particles (with the opposite polarity to the DMAs central rod) was measured. The charging probability can be easily obtained from the ratio of the number-concentration of the charged particles to the number-concentration of the total particles.Fig. 1


Experimental determination of the steady-state charging probabilities and particle size conservation in non-radioactive and radioactive bipolar aerosol chargers in the size range of 5-40 nm.

Kallinger P, Szymanski WW - J Nanopart Res (2015)

Schematic of the experimental setup for the charging probability and particle size conservation measurements
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4385563&req=5

Fig1: Schematic of the experimental setup for the charging probability and particle size conservation measurements
Mentions: The size-dependent steady-state charging probability of the different chargers was measured by means of a tandem DMA setup with the charger of interest placed in between of the two DMAs (Fig. 1). Both of the DMAs used in this study were custom built (according to our specifications by tapcon & analysesysteme, Salzburg, Austria; Kallinger et al. 2013), hydro-mechanically identical and operating at the same polarity. In this setup, the fact was used that the particles exiting a DMA are both monomobile (i.e. of the same electrical mobility) and all of them are unipolar charged. With the investigated charger turned off, the particles remained in their state of charge, and therefore the total number-concentration at the inlet of DMA 2 could be measured with DMA 2 and CPC 2. With the charger turned on, only the number-concentration of the charged particles (with the opposite polarity to the DMAs central rod) was measured. The charging probability can be easily obtained from the ratio of the number-concentration of the charged particles to the number-concentration of the total particles.Fig. 1

Bottom Line: For particular experimental conditions, some deviations from the chosen theoretical model were found for all chargers.For very small particle sizes, the AC-corona charger showed particle losses at low flow rates and did not reach steady-state charge equilibrium at high flow rates.Practically, excellent particle size conservation was found for all three chargers.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.

ABSTRACT

Three bipolar aerosol chargers, an AC-corona (Electrical Ionizer 1090, MSP Corp.), a soft X-ray (Advanced Aerosol Neutralizer 3087, TSI Inc.), and an α-radiation-based (241)Am charger (tapcon & analysesysteme), were investigated on their charging performance of airborne nanoparticles. The charging probabilities for negatively and positively charged particles and the particle size conservation were measured in the diameter range of 5-40 nm using sucrose nanoparticles. Chargers were operated under various flow conditions in the range of 0.6-5.0 liters per minute. For particular experimental conditions, some deviations from the chosen theoretical model were found for all chargers. For very small particle sizes, the AC-corona charger showed particle losses at low flow rates and did not reach steady-state charge equilibrium at high flow rates. However, for all chargers, operating conditions were identified where the bipolar charge equilibrium was achieved. Practically, excellent particle size conservation was found for all three chargers.

No MeSH data available.