Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analysis of hydrogen permeation tests considering two different
  modelling approaches for grain boundary trapping in iron   The electrochemical permeation test is one of the most used methods for
characterising hydrogen diffusion in metals. The flux of hydrogen atoms
registered in the oxidation cell might be fitted to obtain apparent
diffusivities. The magnitude of this coefficient has a decisive influence on
the kinetics of fracture or fatigue phenomena assisted by hydrogen and depends
largely on hydrogen retention in microstructural traps. In order to improve the
numerical fitting of diffusion coefficients, a permeation test has been
reproduced using FEM simulations considering two approaches: a continuum 1D
model in which the trap density, binding energy and the input lattice
concentrations are critical variables and a polycrystalline model where
trapping at grain boundaries is simulated explicitly including a segregation
factor and a diffusion coefficient different from that of the interior of the
grain. Results show that the continuum model captures trapping delay, but it
should be modified to model the trapping influence on the steady state flux.
Permeation behaviour might be classified according to different regimes
depending on deviation from Fickian diffusion. Polycrystalline synthetic
permeation shows a strong influence of segregation on output flux magnitude.
This approach is able to simulate also the short-circuit diffusion phenomenon.
The comparison between different grain sizes and grain boundary thicknesses by
means of the fitted apparent diffusivity shows the relationships between the
registered flux and the characteristic parameters of traps.

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The categories of this paper are: q-alg
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
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The categories of this paper are: econ
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
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The categories of this paper are: ao-sci
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The categories of this paper are: math-ph
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The categories of this paper are: q-fin
1
The categories of this paper are: cs
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The categories of this paper are: eess