Deterministic and statistical methods for the characterisation of poroelastic media from multi-observation sound absorption measurements

Sound absorption measurements, made with a diverging beam in sea water, are given. They cover frequencies from 0.35 to 2.3 Mc. per second and are somewhat lower than those given by Richardson for fresh water. Conclusive comparison between these results and fresh water results cannot be made. Advantages of using long distances are discussed.

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Fabrication of cellulose-based aerogel for thermal and acoustic insulation applications

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/947/1/012030 ◽

2021 ◽

Vol 947 (1) ◽

pp. 012030

Author(s):

Ngan N T Thai ◽

Quyen N D Chau ◽

Nam D Do ◽

Tuan D Tran ◽

Ha K P Huynh ◽

...

Keyword(s):

Thermal Conductivity ◽

Sound Absorption ◽

Young Modulus ◽

High Porosity ◽

Water Contact ◽

Acoustic Insulation ◽

Conductivity Water ◽

Oil Adsorption ◽

High Sound ◽

Absorption Measurements

Abstract A method to prepare aerogels from rice straw and polyvinyl alcohol in the presence of fiberglass and glutaraldehyde is herein reported. The morphology, pore structure and physical properties of the aerogels were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), thermal conductivity, water contact angle (WCA) measurements, oil adsorption and sound absorption measurements. The obtained aerogels should be considered as a promising material for upcoming applications, since it has high porosity (up to 93.72%), low density (0.083-0.127 g/cm3), super low thermal conductivity (0.032-0.048 W/mK), high Young modulus (0.201-1.207 MPa), high sound absorption (absorption coefficient of 0.87) and a good oil adsorption capacity (4.8 g/g).

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Evaluating the bonding condition of NASA spray on foam insulation using audio frequency sound absorption measurements

10.31274/rtd-20201107-513 ◽

2005 ◽

Author(s):

Todd Alan Thompson

Keyword(s):

Sound Absorption ◽

Audio Frequency ◽

Frequency Sound ◽

Bonding Condition ◽

Absorption Measurements

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Sound Absorption Measurements and Numerical Estimation of Non Acoustical Parameters of some Moroccan Raw Green Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1051.95 ◽

2014 ◽

Vol 1051 ◽

pp. 95-101

Author(s):

Garoum Mohammed ◽

Chaimaa Benayad

Keyword(s):

Sound Absorption ◽

Normal Incidence ◽

Optimization Techniques ◽

Acoustical Parameters ◽

Acoustical Properties ◽

Thermal Insulating ◽

Green Materials ◽

Direct Measurements ◽

Inverse Estimation ◽

Absorption Measurements

Knowledge of acoustical properties of granular and fibrous sustainable materials has been stimulated thanks to their rather easy handling and durability. In this work direct measurements of the normal incidence sound absorption coefficient of three non consolidated materials (esparto fibers, cork and perlite) have been carried out using the so-called transfer function method. These materials are plentiful in Morocco and they require low amounts of energy for processing, which makes them attractive as either thermal insulating or sound absorbing materials. Results show that the acoustical efficiency of studied materials is comparable to traditional materials. In addition, an inverse estimation of non acoustical parameters (flow resistivity, tortuosity and porosity) of these materials has been performed introducing a new predictability approach. This is based on Global Sensitivity Analysis combined with Global Numerical Optimization Techniques, regarding most usual mathematical models.

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