Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A 2-D Model for friction of complex anisotropic surfaces   The friction force observed at macroscale is the result of interactions at
various lower length scales that are difficult to model in a combined manner.
For this reason, simplified approaches are required, depending on the specific
aspect to be investigated. In particular, the dimensionality of the system is
often reduced, especially in models designed to provide a qualitative
description of frictional properties of elastic materials, e.g. the
spring-block model. In this paper, we implement for the first time a two
dimensional extension of the spring-block model, applying it to structured
surfaces and investigating by means of numerical simulations the frictional
behaviour of a surface in the presence of features like cavities, pillars or
complex anisotropic structures. We show how friction can be effectively tuned
by appropriate design of such surface features.

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The categories of this paper are: atom-ph
2
The categories of this paper are: math
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The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
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The categories of this paper are: supr-con
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The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
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The categories of this paper are: eess
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The categories of this paper are: chem-ph
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The categories of this paper are: acc-phys
3
The categories of this paper are: physics