Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Asymptotic analysis of drug dissolution in two layers having widely
  differing diffusion coefficients   This paper is concerned with a diffusion-controlled moving-boundary problem
in drug dissolution, in which the moving front passes from one medium to
another for which the diffusion coefficient is many orders of magnitude
smaller. It has been shown in an earlier paper that a similarity solution
exists while the front is passing through the first layer, but that this breaks
down in the second layer. Asymptotic methods are used to understand what is
happening in the second layer. Although this necessitates numerical
computation, one interesting outcome is that only one calculation is required,
no matter what the diffusion coefficient is for the second layer.

1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph