Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A non-isothermal, non-equimolar transient kinetic model for gas-solid
  reactions   A numerical model is presented, designed to simulate the kinetic and thermal
behaviour of a porous pellet in which any gas-solid reaction is taking place.
Its novelty consists in the fact that it can deal with reactions whether they
are exothermic or endothermic, whether they are equimolar or not, whether they
are reversible or irreversible, and further reactions in the transient regime
and even the possible presence of inert gases and solids can be treated. The
numerical scheme is based on the finite volume method in an implicit
formulation, with a specific treatment of the thermal source term for strongly
exothermic reactions. The model was validated by comparison with analytical and
numerical solutions from the literature and was used to simulate the exothermic
reaction involved in the oxidation of zinc sulphide.

34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom