Effects of Shape and Orientation to be Considered for Optical Particle Sizing

Killinger, R. T.; Zerull, R. H.

doi:10.1007/978-1-4757-1983-3_34

Cited by 14 publications

(6 citation statements)

References 1 publication

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“…The results in both cases have a Poisson distribution as might be expected, with a mean particle alignment angle of 23.2 O with no electric field present and of 21 3. " in the presence of the field, with the mean measurement errors for the two cases were t 1.37" and t 1.36 O respectively.…”

supporting

confidence: 68%

“…However, in general these instruments do not attempt to assess particle shape but rather attribute a spherical volume equivalent size to each measured particle, based upon an empirical or theoretical calibration function. Particle size spectra may be produced over ranges from sub-micron to tens of microns, though the accuracy and validity of such results has been the subject of some considerable research by workers in the field, for example: Gebhart and Anselm [l], Bottlinger and Umhauer [2], and Killinger et al [3]. The problem lies in the fact that the instruments attempt to assess the particle size by measuring the scattered light intensity at one or a range of scattering angles, and that this intensity is usually dependent on not only the particle's size but also its shape and orientation with respect to the incident illumination.…”

Section: Introductionmentioning

confidence: 99%

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A method for investigating the orientational behaviour of fibrous particles in gaseous flow

Hirst

Kaye

Buckley

et al. 1995

Part & Part Syst Charact

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A method is described by which the angular orientation distribution of fibrous particles carried in a gaseous stream may be investigated. The method is based upon the interpretation of the spatial intensity distribution or scattering profile of laser light scattered by individual fibres. The scattering instrument used to capture the profiles is described, and the mathematical computation required to ascertain the orientation of each particle at the measurement point is detailed. Illustrative results are given for a study of airborne micromachined silicon particles of 12 pm length and 1.0 pm by 1.5 pm cross-section. The method is currently being employed by the authors to investigate ways of improving the orientation control over nonspherical particles in systems such as aerodynamic particle sizers and particle shape classifiers, since lack of particle orientation control is known to adversely affect the measurement accuracy of both these types of instrument.

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supporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

A method for investigating the orientational behaviour of fibrous particles in gaseous flow

Hirst

Kaye

Buckley

et al. 1995

Part & Part Syst Charact

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“…Previously angles around 160 • were used because it was expected that polarization effects were a maximum there (Card and Jones 1995, Liou and Coleman 1980, Zerull et al 1986. Here angles around 120 • were used due to evidence that cross-polarization is very shape sensitive in this region (Killinger and Zerull 1988, Mugnai and Wiscombe 1989.…”

Section: Introductionmentioning

confidence: 99%

An investigation of the potential of polarized light scattering for the characterization of irregular particles

Card¹,

Jones²

1999

J. Phys. D: Appl. Phys.

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An investigation has been carried out into the possibility of using polarization methods to characterize clouds of irregular particles. Measurements were made at scattering angles between approximately 115 • and 135 • , where it was expected that polarization effects would have maximum variation with shape. It was found that the angular variation of any polarization property was similar for most particles. Further, as a consequence of reciprocity, the useful parameters were limited to the scattered intensities for two incident polarization states and one cross-polarized intensity. The only useful correlation appeared to be between cross-polarization and the 'roundness' of the particles, although different correlations are observed between particles which are inherently isotropic and those which are anisotropic. The main conclusion of the study is that polarization can be used to measure the average roundness of particles in a cloud and has the potential to discriminate between crystals of different structure.

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“…This means that the use of other devices and other light sources (LASER) will deliver different results. Investigations of monochromatic light scattering have shown that the shape and structure influence is much stronger than with the white-light device utilized here [22]. The effort required for the determination of a transformation matrix for a particular substance is relatively high.…”

Section: Discussionmentioning

confidence: 87%

Single Particle Light Scattering Size Analysis: Quantification and elimination of the effect of particle shape and structure

Bottlinger

Umhauer

1989

Part & Part Syst Charact

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When measuring scattered light from single particles (as realized in various methods of scattered light‐particle size counting analysis) nonspherical particles and particles with inner structure produce different signal heights (scattered light intensities) when differently oriented in the measuring volume. To study the influence of the particle shape and structure, the representative spectrum of all signal heights reflecting all of the possible orientations of the particle in the measuring volume was recorded from individual particles of a definite material in each case. Additionally from every particle an equivalent diameter was determined. The measurements lead to a very precise calibration curve and to a transformation matrix, that describes the influence of shape and structure on scattered light‐counting analyses in case of the specific material. It is then possible to simulate measurements to determine the loss in resolution caused by the influence of shape and structure and to eliminate this effect from conventional scattered light analyses. The paper presents the concept together with results of simulation and elimination calculations for the material limestone and quartz. The corrected size distributions are compared with results by other methods. On the basis of this comparison it is discussed how successful the method is to recover a higher resolution.

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Effects of Shape and Orientation to be Considered for Optical Particle Sizing

Cited by 14 publications

References 1 publication

A method for investigating the orientational behaviour of fibrous particles in gaseous flow

A method for investigating the orientational behaviour of fibrous particles in gaseous flow

An investigation of the potential of polarized light scattering for the characterization of irregular particles

Single Particle Light Scattering Size Analysis: Quantification and elimination of the effect of particle shape and structure

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