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Microwave and Acoustic Absorption Metamaterials
Physical Review Applied, 2022 Wave absorption metamaterials have been an enduring topic over the past two decades, propelled not only by novel scientific advances, but also by their extensive application potential. In this review, we aim to provide some general insights into the absorption mechanism common to both microwave and acoustic systems.
Sichao Qu, Ping Sheng
exaly +4 more sources
Optimal Absorption of Acoustic Waves by a Boundary [PDF]
SIAM Journal on Control and Optimization, 2021 In the aim to find the simplest and most efficient shape of a noise absorbing wall to dissipate the acoustical energy of a sound wave, we consider a frequency model described by the Helmholtz equation with a damping on the boundary. The well-posedness of the model is shown in a class of domains with d-set boundaries (N -- 1 $\le$ d < N).
Frédéric Magoulès +3 more
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Absorption characteristics of large acoustic metasurfaces
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2022 Metasurfaces formed of arrays of subwavelength resonators are often tuned to ‘critically couple’ with incident radiation, so that at resonance dissipative and radiative damping are balanced and absorption is maximized. Such design criteria are typically derived assuming an infinite metasurface, whereas the absorption characteristics of ...
O. Schnitzer, R. Brandão
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Acoustic absorption by sunspots
The Astrophysical Journal, 1987 The paper presents the initial results of a series of observations designed to probe the nature of sunspots by detecting their influence on high-degree p-mode oscillations in the surrounding photosphere. The analysis decomposes the observed oscillations into radially propagating waves described by Hankel functions in a cylindrical coordinate system ...
D. C. Braun +2 more
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Perfect Absorption in Mirror-Symmetric Acoustic Metascreens [PDF]
Physical Review Applied, 2020 Mirror-symmetric acoustic metascreens producing perfect absorption independently of the incidence side are theoretically and experimentally reported in this work. The mirror-symmetric resonant building blocks of the metascreen support symmetric and antisymmetric resonances that can be tuned to be at the same frequency (degenerate resonances).
V. Romero-García +7 more
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The acoustical absorption by air-saturated aerogel powders
The Journal of the Acoustical Society of America, 2022 The acoustical behavior of air-saturated aerogel powders in the audible frequency range is not well understood. It is not clear, for example, which physical processes control the acoustic absorption and/or attenuation in a very light, loose granular mix in which the grain diameter is on the order of a micron.
Begum, H. +3 more
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Effective acoustic absorption of ETFE membranes and cushions
Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023, 2022 In this paper, we report on measurements of the acoustic absorption coefficient of ETFE membranes and cushions by two types of measurement approaches. The experimental results are compared with material simulations in ODEON® room acoustics ver.17. The absorption was determined via the assumption that the energy which passes through the foil can be ...
Gharibian Lavasani, Sayyed Majid +5 more
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Absorption and Enjoyment During Listening to Acoustically Masked Stories [PDF]
Trends in Hearing, 2020 Comprehension of speech masked by background sound requires increased cognitive processing, which makes listening effortful. Research in hearing has focused on such challenging listening experiences, in part because they are thought to contribute to social withdrawal in people with hearing impairment.
Bjorn Herrmann, Ingrid Johnsrude
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Acoustic properties of green walls: Absorption and insulation [PDF]
Proceedings of Meetings on Acoustics, 2016 In the past few decades, the issue of environmental quality in the urban environment is a recurring theme. Green walls and roofs have demonstrated great efficiency in the attenuation of adverse effects such as heat islands. The thermal characterization of these systems are well studied, however few studies have been carried out on their acoustic ...
Rodolfo Thomazelli +2 more
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Acoustic Imaging and Subsurface Absorption Structur of Sunspots [PDF]
Symposium - International Astronomical Union, 1998 Recently, Chang et al. (1997, hereafter Paper I) developed a new method, based on time-distance curves (Duvall et al. 1993), to construct a three-dimensional acoustic intensity image of the solar interior. Here we report results from another data set.Solar p-mode waves, which are continually generated and dissipated stochastically by the turbulent ...
H.-K. Chang, D.-Y. Chou, B. Labonte
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