Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Energy conversion by surface-tension driven charge separation   In this work, the shear-induced electrokinetic streaming potential present in
free-surface electrolytic flows subjected to a gradient in surface tension is
assessed. Firstly, for a Couette flow with fully resolved electric double layer
(EDL), the streaming potential per surface stress as a function of the Debye
parameter and surface potential is analyzed. By contrast to the Smoluchowski
limit in pressure-driven channel flow, the shear-induced streaming potential
vanishes for increasing Debye parameter (infinitely thin EDL), unless the free
surface contains (induced) surface charge or the flow at the charged, solid
wall is permitted to slip. Secondly, a technical realization of surface-tension
induced streaming is proposed, with surface stress acting on the free
(slipping) surfaces of a micro-structured, superhydrophobic wall. The streaming
potential is analyzed with respect to the slip parameter and surface charge.
Finally, the surface tension is assumed to vary with temperature
(thermocapillarity) or with surfactant concentration (destillocapillarity). The
maximal thermal efficiency is derived and compared to the Carnot efficiency.
For large thermal Marangoni number, the efficiency is severely limited by the
large heat capacity of aqueous solvents. By contrast, destillocapillary flows
may reach conversion efficiencies similar to pressure-driven flow.

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The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: math
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph