Acoustic birefringence via non-Eulerian metamaterials

Zangeneh-Nejad, Farzad; Fleury, Romain

doi:10.1063/1.5090839

Cited by 11 publications

(4 citation statements)

References 65 publications

(28 reference statements)

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“…To start, consider the geometry of figure 1(a), depicting a metamaterial built from intercrossing air-filled acoustic pipes with the radius R=1.5 cm, arranged in a square lattice with the lattice constant a=5 cm. Such kind of metamaterial coils up the space and provides an internal geometrical detour for sound, reducing its effective travelling velocity [52][53][54][55][56]. Consequently, from a macroscopic point of view, the structure effectively acts as a high-index acoustic medium, a result which was already explored in [56].…”

Section: Methodsmentioning

confidence: 99%

Performing mathematical operations using high-index acoustic metamaterials

Zangeneh-Nejad

Fleury

2018

New J. Phys.

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The recent breakthrough in metamaterial-based optical computing devices (2014 Science 343 160) has inspired a quest for similar systems in acoustics, performing mathematical operations on sound waves. So far, acoustic analog computing has been demonstrated using thin planar metamaterials, carrying out the operator of choice in Fourier domain. These so-called filtering metasurfaces, however, are always accompanied with additional Fourier transform sub-blocks, enlarging the computing system and preventing its applicability in miniaturized architectures. Here, employing a simple high-index acoustic slab waveguide, we propose a highly compact and potentially integrable acoustic computing system and demonstrate its proper functioning by numerical simulations. The system directly performs mathematical operation in spatial domain and is therefore free of any Fourier bulk lens. Such compact computing system is highly promising for various applications including high throughput image processing, ultrafast equation solving, and real time signal processing.

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Section: Methodsmentioning

confidence: 99%

Performing mathematical operations using high-index acoustic metamaterials

Zangeneh-Nejad

Fleury

2018

New J. Phys.

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“…Based on the distance between these units, the geometry of each of them, and the properties of the medium in which they are incorporated, this system can influence the acoustic waves that propagate through it in unusual ways. Some of the characteristics identified in such materials include negative refraction [21], band gap [22], birefringence [23], and autocollimation [24]. These properties can be applied in a variety of devices covering different cases such as acoustic barriers [25], acoustic lenses [26], and acoustic absorbers [27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Design Optimization of Three-Layered Metamaterial Acoustic Absorbers Based on PVC Reused Membrane and Metal Washers

Ciaburro

Parente²,

Iannace

et al. 2022

Sustainability

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Waste management represents a critical issue that industrialized countries must necessarily deal with. Sustainable architecture involves the reuse of materials with the aim of significantly reducing the amount of waste produced. In this study, a new layered membrane metamaterial was developed based on three layers of a reused PVC membrane and reused metal washers attached. The membranes were fixed to a rigid support, leaving a cavity between the stacked layers. The samples were used to measure the sound absorption coefficient with an impedance tube. Different configurations were analyzed, changing the number of masses attached to each layer and the geometry of their position. These measurements were subsequently used to train a model based on artificial neural networks for the prediction of the sound absorption coefficient. This model was then used to identify the metamaterial configuration that returns the best absorption performance. The designed metamaterial behaves like an acoustic absorber even at low frequencies.

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“…Acoustic beam splitter is an acoustic device which is capable of splitting a given acoustic wave with any incidence angle into desired directions, which has been widespread researched with protentional applications in many fields ranging from biomedical imaging to multi-beam acoustic sonar system [1,2]. In recent years, acoustic beam splitter with improved performance based on acoustic metamaterials have attracted increasing concerns compared with conventional acoustic beam splitter based on natural materials [3,4]. For example, Graciá -Salgado et al [5] designed a metamaterial with negative density or density near zero to achieve power splitting, the main drawback of the design is the strong transmission losses at the frequencies of negative material properties.…”

Section: Introductionmentioning

confidence: 99%

Infectious Hospital Area, the First Affiliated Hospital of University of Science and Technology of China, Hefei, China

Zhao¹,

Hu²,

Xue³

et al. 2021

BEBM

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With advances in deep learning, neural network based speech enhancement (SE) has developed rapidly in the last decade. Meanwhile, the self-supervised pre-trained model and vector quantization (VQ) have achieved excellent performance on many speech-related tasks, while they are less explored on SE. As it was shown in our previous work that utilizing a VQ module to discretize noisy speech representations is beneficial for speech denoising, in this work we therefore study the impact of using VQ at different layers with different number of codebooks. Different VQ modules indeed enable to extract multiplegranularity speech features. Following an attention mechanism, the contextual features extracted by a pre-trained model are fused with the local features extracted by the encoder, such that both global and local information are preserved to reconstruct the enhanced speech. Experimental results on the Valentini dataset show that the proposed model can improve the SE performance, where the impact of choosing pre-trained models is also revealed.

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Acoustic birefringence via non-Eulerian metamaterials

Cited by 11 publications

References 65 publications

Performing mathematical operations using high-index acoustic metamaterials

Performing mathematical operations using high-index acoustic metamaterials

Design Optimization of Three-Layered Metamaterial Acoustic Absorbers Based on PVC Reused Membrane and Metal Washers

Infectious Hospital Area, the First Affiliated Hospital of University of Science and Technology of China, Hefei, China

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