Triboelectric effect

Tucholski, D., Coal Beneficiation and Triboelectric Effects in a Circulating Fluidized Bed, MS Thesis, Dept, of Mechanical Engineering, Iowa State University, 1992. 

There is a huge amount energy in our environment. And the nature has its own laws of the transformation between the solar, thermal and vibration energy, and electricity, the most universal energy form used in daily life. Currently, only a part of the photovoltaic effect, thermoelectric effect, piezoelectric effect, and triboelectric effect has been investigated, and more efforts are required to carefully understand these effects to further optimize the device structure and enhance the device performance. 

Wang, S., Lin, L., Wang, Z.L., 2012. Nanoscale triboelectric-effect-enabled energy conversion for sustainably powering portable electronics. Nano Lett. 12, 6339-6346. 

Conversely, by constructing the filter medium with a blend of fibres of widely contrasting triboelectric properties, it is claimed by a fibre manufacturer that superior collection efficiency can be obtained. It is further claimed that, by virtue of this enhanced efficiency, a more open structure can be used with consequent advantages in respect of the reduced power consumption required to pull the dust-laden air through the collector. However, although this effect has been used to some advantage in clean air room filtration applications, considerably more research is necessary if the triboelectric effects in industrial dust collection are to be fully understood and exploited. 

A number of researchers have explored the use of triboelectric effects in measuring the properties of the pneumatic conveying systems [12, 13, 14]. Usually the researcher would like to eliminate these charges, but under controlled conditions they can be used to an advantage. Klinzing, et al. [15] have used a field probe that is both nonintrusive and effective in picking up the field variations in the flow of charged particles. 

This firm offers a device that can measure the conductance of the flowing stream and a device that will indicate flow or no flow condition by inserting a probe that picks up triboelectric effects generated. The latter probe can be retracted fi om the flow when not in use while the former is an in-line device having the same diameter as the flowing system. 

In order to confirm that the triboelectric effect does not result in any significant change, a further experiment was done using glass, steel and silicon wafer to examine the extremes of the possible substrates. 

For powders and granular solids, there are two types of antistatic agents surface- and volume-active additives. Surface-active agents, which increase the surface conductivity of individual particles, are effective because triboelectric charge is always situated on the surfaces of individual particles. Most if not all surface-active agents are hygroscopic and thus attract a thin film of water to the surface it is this moisture that is responsible forthe increased surface conduction (van Drumpt, 1991). The effective bulk resistivity of the particles % -may be estimated by assuming that the particles are spherical and of radius R (Jones, 1995). 

A second adverse effect of van der Waals adhesion is a tendency of carrier and photoconductor surfaces to become coated with a thin film of toner residue—a film which progressively impairs the efficiency of toner charging and photoreceptor performance. Salaneck et al. (57) have reported that material transfer amounting to as little as 1 atom/10 surface sites is measurable as a shift in "triboelectric" charging behavior ... 

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