Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Sound absorption in Hilbert Fractal and Coiled Acoustic Metamaterials   We describe here a class of acoustic metamaterials with fractal Hilbert
space-filling and coiled geometry with equal tortuosity for noise mitigation.
Experiments are performed using a four-microphone impedance tube and
benchmarked against non-viscous and viscothermal Finite Element models related
to configurations spanning up to five fractal/geometry orders. We show that the
acoustic absorption can be predicted by the resonance of the cavities
associated to the tortuous paths. For a given fractal/geometry order, the
acoustic absorption at specific frequencies is also enhanced by maximising the
difference between the minimum and maximum fluid particle velocity of the air
inside the patterns. These principles can be used to design high-performance
acoustic metamaterials for sound absorption over broad frequency ranges.

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The categories of this paper are: econ
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph