Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mathematical multi-scale model of water purification   In this work we consider a mathematical model of the water treatment process
and determine the effective characteristics of this model. At the microscopic
length scale we describe our model in terms of a lattice random walk in a
high-contrast periodic medium with absorption. Applying then the upscaling
procedure we obtain the macroscopic model for total mass evolution. We discuss
both the dynamic and the stationary regimes, and show how the efficiency of the
purification process depends on the characteristics of the macroscopic model.

16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th