Measurement of particle size and electrostatic charge distributions on toners using E-SPART analyzer

Mazumder, Malay K.; Ware, R.E.; Yokoyama, Takashi; Rubin, B.J.; Kamp, D.

doi:10.1109/28.85472

Cited by 89 publications

(28 citation statements)

References 3 publications

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“…[14][15][16][17] In the handful of variations that do deal with individual grains, the quantity measured is often the charge to mass ratio 18 or a proxy for charge such as the current signal produced in an induction probe. 19,20 There are at least three experiments that use Faraday cup-like devices to measure the absolute charge of individual grains, [21][22][23] while others such as the E-SPART technique described in Mazumdar et al, 24 which is also capable of measuring the particles' aerodynamic radii, use different variations still. 24 Even so, most of these techniques are restricted to very specific particle sizes, cannot distinguish between different particle compositions, or taint the measurement signal by contributing to the charge being measured.…”

Section: Introductionmentioning

confidence: 99%

In situ granular charge measurement by free-fall videography

Waitukaitis

Jaeger

2013

Review of Scientific Instruments

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We present the design and performance characterization of a new experimental technique for measuring individual particle charges in large ensembles of macroscopic grains. The measurement principle is qualitatively similar to that used in determining the elementary charge by Millikan in that it follows individual particle trajectories. However, by taking advantage of new technology we are able to work with macroscopic grains and achieve several orders of magnitude better resolution in charge to mass ratios. By observing freely falling grains accelerated in a horizontal electric field with a co-falling, high-speed video camera, we dramatically increase particle tracking time and measurement precision. Keeping the granular medium under vacuum, we eliminate air drag, leaving the electrostatic force as the primary source of particle accelerations in the co-moving frame. Because the technique is based on direct imaging, we can distinguish between different particle types during the experiment, opening up the possibility of studying charge transfer processes between different particle species. For the ∼300 μm diameter grains reported here, we achieve an average acceleration resolution of ∼0.008 m/s(2), a force resolution of ∼500 pN, and a median charge resolution ∼6× 10(4) elementary charges per grain (corresponding to surface charge densities ∼1 elementary charges per μm(2)). The primary source of error is indeterminacy in the grain mass, but with higher resolution cameras and better optics this can be further improved. The high degree of resolution and the ability to visually identify particles of different species or sizes with direct imaging make this a powerful new tool to characterize charging processes in granular media.

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Section: Introductionmentioning

confidence: 99%

In situ granular charge measurement by free-fall videography

Waitukaitis

Jaeger

2013

Review of Scientific Instruments

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“…They rely upon the application of an electric field and the drift of electrified dust grains. The field induced drift velocity can be determined using optical or laser systems to study particle trajectories (Kunkel 1950;Mazumder et al 1991) or by extracting dust onto a surface . The fieldinduced drift velocity will be proportional to the electrical force and therefore the electric charge and polarity of the dust grains.…”

Section: Surface Charge Densitymentioning

confidence: 99%

Applications of Electrified Dust and Dust Devil Electrodynamics to Martian Atmospheric Electricity

et al. 2016

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Atmospheric transport and suspension of dust frequently brings electrification, which may be substantial. Electric fields of 10 kV m −1 to 100 kV m −1 have been observed at the surface beneath suspended dust in the terrestrial atmosphere, and some electrification has been observed to persist in dust at levels to 5 km, as well as in volcanic plumes. The interaction between individual particles which causes the electrification is incompletely understood, and multiple processes are thought to be acting. A variation in particle charge with particle size, and the effect of gravitational separation explains to, some extent, the charge structures observed in terrestrial dust storms. More extensive flow-based modelling demonstrates that bulk electric fields in excess of 10 kV m −1 can be obtained rapidly (in less than 10 s) from rotating dust systems (dust devils) and that terrestrial breakdown fields can be obtained. Modelled profiles of electrical conductivity in the Martian atmosphere suggest the possibility of dust electrification, and dust devils have been suggested as a mechanism of charge separation able to maintain current flow between one region of the atmosphere and another, through a global circuit. Fundamental new understanding of Martian atmospheric electricity will result from the ExoMars mission, which carries the DREAMS (Dust characterization, Risk Assessment, and Environment Analyser on the Martian Surface)-B R.G. Harrison

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“…Until now, majority of the work was involved in developing the understanding on the tribo-charging mechanism [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. Several studies were also carried out to know the tribocharging characteristics in pneumatic conveying [50][51][52][53][54][55][56][57][58][59][60][61][62][63] and gassolid fluidized bed system [64][65][66][67].…”

Section: Introductionmentioning

confidence: 99%