Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhanced solar evaporation of water from porous media, through capillary
  mediated forces and surface treatment   The relative influence of the capillary, Marangoni, and hydrophobic forces in
mediating the evaporation of water from carbon foam based porous media, in
response to incident solar radiation, are investigated. It is indicated that
inducing hydrophilic interactions on the surface, through nitric acid treatment
of the foams, has a similar effect to reduced pore diameter and the ensuing
capillary forces. The efficiency of water evaporation may be parameterized
through the Capillary number (Ca), with a lower Ca being preferred. The
proposed study is of much relevance to efficient solar energy utilization.

19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph