Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Sound wave velocities in dry and lubricated granular packings packings:
  numerical simulations and experiments   Numerical simulations are used to investigate the origins of the different
wave velocities measured in dense granular samples assembled with different
methods. Glass bead packings are prepared in the lab either by pouring and
vibrating the dry material in a container, or by mixing with a very small
amount of a viscous lubricant. Lubricated samples, although less dense, exhibit
significantly higher wave velocities for confining pressures in the 100 kPa
range. Numerical predictions for elastic moduli agree much better with
experimental results when the computational preparation of the samples mimics
the laboratory one, albeit in a simplified manner. A plausible explanation to
the laboratory observations is that the coordination number, which influences
the material stiffness more than its density, is notably higher in lubricated
packings.

13
The categories of this paper are: quant-ph
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The categories of this paper are: stat
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The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat
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The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int