Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Drying Patterns: Sensitivity to Residual Stresses   Volume alteration in solid materials is a common cause of material failure.
Here we investigate the crack formation in thin elastic layers attached to a
substrate. We show that small variations in the volume contraction and
substrate restraint can produce widely different crack patterns ranging from
spirals to complex hierarchical networks. The networks are formed when there is
no prevailing gradient in material contraction whereas spirals are formed in
the presence of a radial gradient in the contraction of a thin elastic layer.

27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys