Dresden 2017 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 39: Particulate Matter II: From microscopic interactions to collective motion (Focus session)
DY 39.2: Vortrag
Mittwoch, 22. März 2017, 15:30–15:45, ZEU 118
Tribo-electric charging in granular matter — •André Schella1, Stephan Herminghaus1, and Matthias Schröter1,2 — 1Max-Planck Institut für Dynamik und Selbstorganisation (MPIDS), Am Faßberg 17, 37077 Göttingen — 2Institut für Multiskalensimulation, Nägelsbachstrasse 49b, 91052 Erlangen
If granular particles touch either walls or other beads, they do tribo-charge. The charge modifies the way these particles interact, causing e. g. lightnings in dust storms, clogging of pipes or even dust explosions [1]. Despite its ubiquity in nature and technology, little is known about the mechanisms behind tribo-electric charging [2]. In our contribution, we will show that tribo-charging in shaken granular media can be controlled via the ambient humidity [3]. Even though the charging of a single bead is related to microscopic processes, it has consequences for the physics of the entire bed: First, charging in binary mixtures can be strong enough to overcome segregation mechanisms. Second, charges alter the structural properties, like the contact number and Voronoi volumes, of the grains. And third, same-sized binary mixtures form macroscopic, granular crystals. [1] J. Duran, Sands, Powders, and Grains, Springer, New York, 2000 [2] L. McCarty and G. Whitesides; Angew. Chem. Int. Ed. 47 2188 (2008) [3] A. Schella et al., arXiv:1609.04639