Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Influence of humidity on the tribo-electric charging and segregation in
  shaken granular media   We study the effect of humidity on the charge accumulation of polymer
granulates shaken vertically in a stainless steel container. The setup allows
to control the humidity level from 5 % to 100 %RH while performing automated
charge measurements in a Faraday cup directly connected to the shaking
container. We find that samples of approximately 2000 polymer spheres become
highly charged at low humidity levels (<30 %RH), but acquire almost no charge
for humidity levels above 80 %RH. The transition between these two regimes does
depend on the material, as does the sign of the charge. For the latter we find
a correlation with the contact angle of the polymer with only very hydrophilic
particles attaining positive charges. We show that this humidity dependence of
tribo-charging can be used to control segregation in shaken binary mixtures.

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The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
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The categories of this paper are: chem-ph
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th