Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Deformation and tribology of multi-walled hollow nanoparticles   Multi-walled hollow nanoparticles made from tungsten disulphide (WS$_2$) show
exceptional tribological performance as additives to liquid lubricants due to
effective transfer of low shear strength material onto the sliding surfaces.
Using a scaling approach based on continuum elasticity theory for shells and
pairwise summation of van der Waals interactions, we show that van der Waals
interactions cause strong adhesion to the substrate which favors release of
delaminated layers onto the surfaces. For large and thin nanoparticles, van der
Waals adhesion can cause considerable deformation and subsequent delamination.
For the thick WS$_2$ nanoparticles, deformation due to van der Waals
interactions remains small and the main mechanism for delamination is pressure
which in fact leads to collapse beyond a critical value. We also discuss the
effect of shear flow on deformation and rolling on the substrate.

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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: physics
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The categories of this paper are: eess
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The categories of this paper are: q-alg
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The categories of this paper are: chem-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-th