Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Retraction of dissolution front in natural porous media   The dissolution of porous materials in a flow field shapes the morphologies
of many geologic landscapes. Identifying the dissolution front, the interface
between the reactive and the unreactive regions in a dissolving medium, is a
prerequisite for studying dissolution kinetics. Despite its fundamental
importance, the dynamics of a dissolution front in an evolving natural
microstructure has never been reported. Here we show an unexpected spontaneous
migration of the dissolution front against the pressure gradient of a flow
field. This retraction stems from the infiltration instability induced surface
generation, which can lead to a reactive surface dramatically greater than the
ex situ geometric surface. The results are supported by a very good agreement
between observations made with real time X-ray imaging and simulations based on
static images of a rock determined by nanoCT. They both show that the in situ
specific surface area of natural porous media is dependent on the flow field
and reflects a balancing between surface generation and destruction. The
reported dynamics challenge many long-held understanding of water-rock
interactions and shed light on reconciling the discrepancies between field and
laboratory measurements of reaction kinetics.

31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph