Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generalised Multi-Rate Models for conjugate transfer in heterogeneous
  materials   We propose a novel macroscopic model for conjugate heat and mass transfer
between a \emph{mobile region}, where advective transport is significant, and a
set of \emph{immobile regions} where diffusive transport is dominant. Applying
a spatial averaging operator to the microscopic equations, we obtain a
\emph{multi-continuum} model, where an equation for the average concentration
in the mobile region is coupled with a set of equations for the average
concentrations in the immobile regions. Subsequently, by mean of a spectral
decomposition, we derive a set of equations that can be viewed as a
generalisation of the multi-rate mass transfer (MRMT) model, originally
introduced by Haggerty & Gorelick. This new formulation does not require any
assumption on local equilibrium or geometry. We then show that the MRMT can be
obtained as the leading order approximation, when the mobile concentration is
in local equilibrium. The new Generalised Multi-Rate Mode (GMRM) has the
advantage of providing a direct method for calculating the model coefficients
for immobile regions of arbitrary shapes, through the solution of appropriate
micro-scale cell problems. An important finding is that a simple re-scaling or
re-parametrisation of the transfer rate coefficient (and thus, the memory
function) is not sufficient to account for the flow field in the mobile region
and the resulting non-uniformity of the concentration at the interfaces between
mobile and immobile regions.

35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
18
The categories of this paper are: econ
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con