Sound absorption measurements at 10–60 kHz in near‐freezing sea water

1975 ◽  
Vol 58 (3) ◽  
pp. 608-619 ◽  
Author(s):  
G. R. Garrison ◽  
R. E. Francois ◽  
E. A. Pence
Keyword(s):  
Sound Absorption ◽  
Sea Water ◽  
Absorption Measurements

ABSORPTION MEASUREMENTS OF SOUND IN SEA WATER

1948 ◽  
Vol 26a (5) ◽  
pp. 306-312 ◽  
Author(s):  
G. J. Thiessen ◽  
F. W. Simpson ◽  
J. R. Leslie
Keyword(s):  
Fresh Water ◽  
Sound Absorption ◽  
Sea Water ◽  
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.

Additional sound absorption measurements in near‐freezing sea water

1976 ◽  
Vol 59 (6) ◽  
pp. 1278-1283 ◽  
Author(s):  
G. R. Garrison ◽  
E. W. Early ◽  
T. Wen
Keyword(s):  
Sound Absorption ◽  
Sea Water ◽  
Absorption Measurements

Investigation of chemical sound absorption in sea water: Part III

1981 ◽  
Vol 70 (1) ◽  
pp. 143-148 ◽  
Author(s):  
R. H. Mellen ◽  
D. G. Browning ◽  
V. P. Simmons
Keyword(s):  
Sound Absorption ◽  
Sea Water

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

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).

SOUND SPEED AND ABSORPTION STUDIES OF MARINE SEDIMENTS BY A RESONANCE METHOD

Geophysics ◽  
1960 ◽  
Vol 25 (2) ◽  
pp. 451-467 ◽  
Author(s):  
George Shumway
Keyword(s):  
Grain Size ◽  
Sound Speed ◽  
Absorption Maximum ◽  
Volume Fraction ◽  
Sea Water ◽  
Resonance Method ◽  
Unconsolidated Sediments ◽  
Linear Absorption ◽  
Average Value ◽  
Absorption Measurements

Laboratory measurements of compressional sound speed, and absorption, have been made on 111 unconsolidated marine sediment samples, ranging from shallow water sands to deep‐sea clays. In addition, determinations were made of porosity, wet density, and grain size distributions. Frequencies between 20 kc/sec and 37 kc/sec were used for the acoustic studies. Sound speed values at room temperature range from 1.474 km/sec for a red medium clay to 1.785 km/sec for a medium sand. More than one‐third of the values are lower than the value for sea water alone. Variations in the speed of sound in unconsolidated sediments as found in nature are caused by the following factors, in order of importance: (1) porosity, because of the great difference in compressibility of water and mineral grains; (2) the factor which produces rigidity, which appears to be related to the abundance of coarse grains; (3) pressure; (4) temperature; (5) compressibility of the grain aggregate, determined from compressibilities of individual minerals. Sound absorption measurements ranged from 0.5 db/m for a medium clay (28.4 kc/sec) to about 20 db/m for silts and fine sands (between 30 and 37 kc/sec). An absorption maximum occurs for sediments of intermediate porosity (0.45–0.6) and intermediate grain size (0.031 mm–0.25 mm). The expression [Formula: see text], where α is the linear absorption coefficient, M is a frequency‐dependent factor related to the sediment volume fraction of grains in mutual contact, and [Formula: see text] is a computable total acoustically effective grain surface area, predicts the absorption values and the absorption maximum. Absorption measurements at more than one frequency between 20 kc/sec and 37 kc/sec were obtained for 65 samples. Assuming that absorption is directly proportional to frequency raised to a power n, the data yield an average value of n equal to 1.79, with a standard deviation of 0.98.

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

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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