Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Ultrasonic probing of the elastic properties of PMMA bead packings and
  their rearrangement during pressure sintering
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc