Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Timescales in creep and yielding of attractive gels   The stress-induced yielding scenario of colloidal gels is investigated under
rough boundary conditions by means of rheometry coupled to local velocity
measurements. Under an applied shear stress, the fluidization of gels made of
attractive carbon black particles suspended in a mineral oil is shown to
involve a previously unreported shear rate response $\dot \gamma (t)$
characterized by two well-defined and separated timescales $\tau_c$ and
$\tau_f$. First $\dot \gamma(t)$ decreases as a weak power law strongly
reminiscent of the primary creep observed in numerous crystalline and amorphous
solids, coined the "Andrade creep." We show that the bulk deformation remains
homogeneous at the micron scale, which demonstrates that if plastic events take
place or if any shear transformation zone exists, such phenomena occur at a
smaller scale. As a key result of this paper, the duration $\tau_c$ of this
creep regime decreases as a power law of the viscous stress, defined as the
difference between the applied stress and the yield stress with an exponent
ranging between 2 and 3 depending on the gel concentration. The end of this
first regime is marked by a jump of the shear rate by several orders of
magnitude, while the gel slowly slides as a solid block experiencing strong
wall slip at both walls, despite rough boundary conditions. Finally, a second
sudden increase of the shear rate is concomitant to the full fluidization of
the material which ends up being homogeneously sheared. The corresponding
fluidization time $\tau_f$ robustly follows an exponential decay with the
applied shear stress as already reported for smooth boundary conditions.
Finally, we highlight a few features that are common to attractive colloidal
gels and to solid materials by discussing our results in the framework of
theoretical approaches of solid rupture (kinetic, fiber bundle, and transient
network models).

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The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
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The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
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The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
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The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas