Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Equation of state for random sphere packing with arbitrary adhesion and
  friction   We systematically generate a large set of random micro-particle packings over
a wide range of adhesion and friction by means of adhesive contact dynamics
simulation. The ensemble of generated packings covers a range of volume
fraction $\phi$ from $0.135 \pm 0.007$ to $0.639 \pm 0.004$, and of
coordination number $Z$ from $2.11 \pm 0.03$ to $6.40 \pm 0.06$. We determine
$\phi$ and $Z$ at four limits (random close packing, random loose packing,
adhesive close packing, and adhesive loose packing), and find a universal
equation of state $\phi(Z)$ to describe packings with arbitrary adhesion and
friction. From a mechanical equilibrium analysis, we determine a critical
friction coefficient $\mu_{\rm f, c}$: when the friction coefficient $\mu_{\rm
f}$ is below $\mu_{\rm f, c}$, particles' rearrangements are dominated by
sliding, otherwise, they are dominated by rolling. Because of this reason, both
$\phi(\mu_{\rm f})$ and $Z(\mu_{\rm f})$ change sharply across $\mu_{\rm f,
c}$. Finally, we generalize the Maxwell counting argument to micro-particle
packings, and show that the loosest packing, i.e., adhesive loose packing,
satisfies the isostatic condition at $Z=2$.

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The categories of this paper are: math
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
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The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th