A sampling method with separated deposition of airborne fibres and other particles

Zebel, G.; Hochrainer, D.; Boose, C.A.

doi:10.1016/0021-8502(77)90008-8

Cited by 17 publications

(7 citation statements)

References 4 publications

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“…Zebel, Hochrainer, and Boose (1977) employed an electric mobility spectrometer to separate airborne fibers from spherical-shaped particles. They found that fibrous particles in an electric field deposit on the electrode faster than spherical particles with the same aerodynamic diameter because of higher charge density of fibrous particles.…”

Section: Introductionmentioning

confidence: 99%

Understanding ion-mobility and transport properties of aerosol nanowires

Kim

Mulholland

Zachariah

2007

Journal of Aerosol Science

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Section: Introductionmentioning

confidence: 99%

Understanding ion-mobility and transport properties of aerosol nanowires

Kim

Mulholland

Zachariah

2007

Journal of Aerosol Science

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“…Several researchers attempted to charge bers and separate them according to length. Grif ths (1988) built such a device, based on earlier work by Zebel et al (1977) and Hochrainer et al (1978), for use as a sampler for asbestos that would allow easier counting of long bers. Some separation was achieved in these devices, though no further development was carried out.…”

Section: Introductionmentioning

confidence: 99%

Performance Evaluation of a Fiber Length Classifier

Deye¹,

Gao²,

Baron³

et al. 1999

Aerosol Science and Technology

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ABSTRACT. A performance evaluation was conducted on a differential mobility classi er that separates bers according to length using dielectrophoresis. The classi er had been constructed and used for several applications in previous studies. The performance of the classi er was predicted using a two-dimensional axisymmetric model of the ow eld and then calculating particle trajectories for a variety of conditions. Based on the ow calculations, several regions of the classi er were improved to reduce likelihood of turbulent losses. For a given total ow through the classi er and a maximum voltage across the electrodes, the performance of the classi er was found to depend on the ratios of the aerosol ow to the inner and the outer sheath ows. It was found that the minimum classi able length, the minimum length distribution width, and the throughput of classi ed bers can each be optimized, but not independently. Several approaches to testing the resolution of the classi er were tried. The rst was to measure the length distribution of bers passing through the classi er under different conditions using electron microscopy. However, this was a slow and imprecise measure of performance. Two approaches using monodisperse latex spheres were used; one operated the instrument as an electrical mobility (electrophoresis) analyzer and the other evaluated only the ow system accuracy. All measures indicate that the classi er operates close to theoretical performance, but improvements are still possible. Suggested improvements require redesign of the ow system and improved electrode alignment.

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“…In unipolar diffusion charging the source contains ions of only one polarity. The charging rate (charges/s) in the continuum regime for a single cylinder-like fiber is (Zebel et al, 1977): where af is the fiber radius, nu is the ion concentration at reference distant r,, Q, is the charge per unit length of the fiber, D,,, is the ion diffusion coefficient (0.03 cm2/s), and q, is the number of elementary charges per ion. The charging time for the fiber to accumulate Q, charges is defined as:…”

Section: Unipolar Chargingmentioning

confidence: 99%

“…Electrostatic forces have been effectively applied for pollution control of submicron size particles. Using electrostatic separation, Zebel et al (1977) showed theoretically and experimentally that the electric mobility of a fiber is 1.8 times that of a sphere with an equal aerodynamic diameter. The electric charge on particles depends on the particle size and shape, ion concentration, applied electric field and residence time in the charger.…”

Section: Introductionmentioning

confidence: 99%