Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Desalination shocks in microstructures   Salt transport in bulk electrolytes is limited by diffusion and convection,
but in microstructures with charged surfaces (e.g. microfluidic devices, porous
media, soils, or biological tissues) surface conduction and electro-osmotic
flow also contribute to ionic fluxes. For small applied voltages, these effects
lead to well known linear electrokinetic phenomena. In this paper, we predict
some surprising nonlinear dynamics that can result from the competition between
bulk and interfacial transport at higher voltages. When counter-ions are
selectively removed by a membrane or electrode, a "desalination shock" can
propagate through the microstructure, leaving in its wake an ultrapure
solution, nearly devoid of co-ions and colloidal impurities. We elucidate the
basic physics of desalination shocks and develop a mathematical theory of their
existence, structure, and stability, allowing for slow variations in surface
charge or channel geometry. Via asymptotic approximations and similarity
solutions, we show that desalination shocks accelerate and sharpen in narrowing
channels, while they decelerate and weaken, and sometimes disappear, in
widening channels. These phenomena may find applications in separations
(desalination, decontamination, biological assays) and energy storage
(batteries, supercapacitors) involving electrolytes in microstructures.

13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas