Absorption of Sound Wave by Fabrics

Aso, Sadao; Kinoshita, Rikuhiro

doi:10.4188/jte1955.9.40

Cited by 3 publications

(2 citation statements)

References 3 publications

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“…The imaginary part, on the other hand, is called reactance and relates to the natural oscillation frequency of the surface. If the frequency of the incident wave resonates with the surface, one has Im(Z ω ) ∼ 0, as in [33]. On the other hand, far from resonance, the surface of the cylinder barely moves under the action of the wave and behaves like a hard wall.…”

mentioning

confidence: 95%

Detecting Rotational Superradiance in Fluid Laboratories

et al. 2016

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Rotational superradiance was predicted theoretically decades ago, and is chiefly responsible for a number of important effects and phenomenology in black-hole physics. However, rotational superradiance has never been observed experimentally. Here, with the aim of probing superradiance in the lab, we investigate the behavior of sound and surface waves in fluids resting in a circular basin at the center of which a rotating cylinder is placed. We show that with a suitable choice for the material of the cylinder, surface and sound waves are amplified. Two types of instabilities are studied: one sets in whenever superradiant modes are confined near the rotating cylinder and the other, which does not rely on confinement, corresponds to a local excitation of the cylinder. Our findings are experimentally testable in existing fluid laboratories and, hence, offer experimental exploration and comparison of dynamical instabilities arising from rapidly rotating boundary layers in astrophysical as well as in fluid dynamical systems.

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confidence: 95%

Detecting Rotational Superradiance in Fluid Laboratories

et al. 2016

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“…Research on acoustic textiles both experimentally and theoretically has been done in the area of nonwoven acoustic fabrics, but in-depth studies of woven and knit fabrics are still very limited. Theory and modeling studies on the properties of weight, thickness, porosity, and frequency of sound waves on woven fabrics are still rarely found as a complete and structured formula [20][21][22][23][24]. Several researchers [1, 12-14, 17-19, 23] had investigated the relationship between the impedance and the absorption characteristics of fabric as well as the effects of thickness, weight, and fabric.…”

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confidence: 99%

A Novel Theoretical Modeling for Predicting the Sound Absorption of Woven Fabrics Using Modification of Sound Wave Equation and Genetic Algorithm

Putra

Irwan

Wijayono

et al. 2021

Autex Research Journal

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Woven fabric in Indonesia is generally known as a material for making clothes and it has been applied as an interior finishing material in buildings, such as sound absorbent material. This study presents a new method for predicting the sound absorption of woven fabrics using a modification of the wave equations and using genetic algorithms. The main aim of this research is to study the sound absorption properties of woven fabric by modeling using a modification of the sound wave equations and using genetic algorithms. A new model for predicting the sound absorption coefficient of woven fabric (plain, twill 2/1, rips and satin fabric) as a function of porosity, the weight of the fabric, the thickness of the fabric, and frequency of the sound wave, was determined in this paper. In this research, the sound absorption coefficient equation was obtained using the modification of the sound wave equation as well as using genetic algorithms. This new model included the influence of the sound absorption coefficient phenomenon caused by porosity, the weight of the fabric, the thickness of fabric as well as the frequency of the sound wave. In this study, experimental data showed a good agreement with the model

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COVID-19: Acoustic Measures of Voice in Individuals Wearing Different Facemasks

2023

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Aim The global health pandemic caused by the SARS-coronavirus 2 (COVID-19) has led to the adoption of facemasks as a necessary safety precaution. Depending on the level of risk for exposure to the virus, the facemasks that are used can vary. The aim of this study was to examine the effect of different types of facemasks, typically used by healthcare professionals and the public during the COVID-19 pandemic, on measures of voice. Methods Nineteen adults (ten females, nine males) with a normal voice quality completed sustained vowel tasks. All tasks were performed for each of the six mask conditions: no mask, cloth mask, surgical mask, KN95 mask and, surgical mask over a KN95 mask with and without a face shield. Intensity measurements were obtained at a 1ft and 6ft distance from the speaker with sound level meters. Tasks were recorded with a 1ft mouth-to-microphone distance. Acoustic variables of interest were fundamental frequency (F0), and formant frequencies (F1, F2) for /a/ and /i/ and smoothed cepstral peak prominence (CPPs) for /a/. Results Data were analyzed to compare differences between sex and mask types. There was statistical significance between males and females for intensity measures and all acoustic variables except F2 for /a/ and F1 for /i/. Few pairwise comparisons between masks reached significance even though main effects for mask type were observed. These are further discussed in the article. Conclusion The masks tested in this study did not have a significant impact on intensity, fundamental frequency, CPPs, first or second formant frequency compared to voice output without a mask. Use of a face shield seemed to affect intensity and CPPs to some extent. Implications of these findings are discussed further in the article.

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Absorption of Sound Wave by Fabrics

Cited by 3 publications

References 3 publications

Detecting Rotational Superradiance in Fluid Laboratories

Detecting Rotational Superradiance in Fluid Laboratories

A Novel Theoretical Modeling for Predicting the Sound Absorption of Woven Fabrics Using Modification of Sound Wave Equation and Genetic Algorithm

COVID-19: Acoustic Measures of Voice in Individuals Wearing Different Facemasks

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