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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: 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.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.


Related in: MedlinePlus

Results of the measurement of the relative particle penetration of the electrical ionizer
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Fig4: Results of the measurement of the relative particle penetration of the electrical ionizer

Mentions: The relative particle penetration measurements were done at first with 5 nm particles and a flow rate of 0.6 lpm which are the smallest particle size and lowest flow rate used in this study, because the particle losses were expected to be higher with smaller particles and longer residence times inside the charger (lower flow rates). In case of the 241Am-charger and the soft X-ray based AAN no significant penetration differences were found. For the AC-corona based EI the relative particle penetration (charger on/charger off) was found to be 77 % (=23 % particle losses) for 5 nm and 0.6 lpm which made an investigation at other particle sizes and flow rates necessary for this device. The results of the relative particle penetration for the EI are shown in Fig. 4. Particle losses were measured to be decreasing with increasing particle size and increasing flow through the charger. Virtually no losses were measured at 5.0 lpm flow (for all particle sizes) and at 40 nm (for all flow rates). The most likely explanation for the particle losses in the EI lies in the specific way of operation of a corona charger. The corona needle produces an electrical field with high field strength. The passing aerosol particles may come in contact with this field which leads to a partial particle precipitation inside the charger.Fig. 4


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)

Results of the measurement of the relative particle penetration of the electrical ionizer
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig4: Results of the measurement of the relative particle penetration of the electrical ionizer
Mentions: The relative particle penetration measurements were done at first with 5 nm particles and a flow rate of 0.6 lpm which are the smallest particle size and lowest flow rate used in this study, because the particle losses were expected to be higher with smaller particles and longer residence times inside the charger (lower flow rates). In case of the 241Am-charger and the soft X-ray based AAN no significant penetration differences were found. For the AC-corona based EI the relative particle penetration (charger on/charger off) was found to be 77 % (=23 % particle losses) for 5 nm and 0.6 lpm which made an investigation at other particle sizes and flow rates necessary for this device. The results of the relative particle penetration for the EI are shown in Fig. 4. Particle losses were measured to be decreasing with increasing particle size and increasing flow through the charger. Virtually no losses were measured at 5.0 lpm flow (for all particle sizes) and at 40 nm (for all flow rates). The most likely explanation for the particle losses in the EI lies in the specific way of operation of a corona charger. The corona needle produces an electrical field with high field strength. The passing aerosol particles may come in contact with this field which leads to a partial particle precipitation inside the charger.Fig. 4

Bottom Line: 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.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.


Related in: MedlinePlus