Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The contribution of Brownian motion to the stress in a colloidal
  suspension   The deviatoric stresses of colloidal suspensions are routinely calculated
using the expression introduced by Batchelor [J. Fluid Mech. 83, 97--117
(1977)]. We show by example that the central feature in its derivation, the
thermodynamic force driving particles down the density gradient, is
inconsistent with the motion of the colloids. A new expression for the stress
is proposed.

18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an