Determination of Absolute Sound Levels and Acoustic Absorption Coefficients by Thermocouple Probes—Theory

1954 ◽  
Vol 26 (3) ◽  
pp. 294-310 ◽  
Author(s):  
William J. Fry ◽  
Ruth Baumann Fry
Keyword(s):  
Acoustic Absorption ◽  
Absorption Coefficients ◽  
Sound Levels

Experimental study of wood acoustic absorption characteristics

Holzforschung ◽  
2014 ◽  
Vol 68 (4) ◽  
pp. 467-476 ◽  
Author(s):  
Jerzy Smardzewski ◽  
Wojciech Batko ◽  
Tadeusz Kamisiński ◽  
Artur Flach ◽  
Artur Pilch ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Acoustic Properties ◽  
Acoustic Absorption ◽  
Laboratory Measurements ◽  
Absorption Coefficients ◽  
Tropical Zone ◽  
Fiber Dimensions ◽  
Air Flow Resistivity ◽  
Oak Ash

Abstract The objective of this study was to determine normal impedance on the surface as well as sound absorption coefficients for several wood species from Europe and from the tropical zone. The mathematical models of Miki, Attenborough, and Allard – dealing with acoustic properties of porous materials – have also been compared. The air flow resistivity exhibits a distinct link between fiber dimensions and wood porosity. The highest sound absorption coefficient was found for oak, ash, sapeli, and pine woods at 2 kHz frequency. The Attenborough model provides results closest to laboratory measurements, although it still requires significant improvements. The Miki and Allard models have some drawbacks and should be applied with reservation for the determination of wood acoustic properties.

The Use of Reverse Mirage Spectroscopy to Determine the Absorption Coefficient of Liquid Methanol at CO2 Laser Wavelengths

1989 ◽  
Vol 43 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Dane Bićanić ◽  
Siegfried Krüger ◽  
Paul Torfs ◽  
Bruno Bein ◽  
Frans Harren
Keyword(s):  
Absorption Coefficient ◽  
Co2 Laser ◽  
Probe Beam ◽  
Laser Emission ◽  
Wavelength Region ◽  
Experimental Setup ◽  
Absorption Coefficients ◽  
Experimental Conditions ◽  
Liquid Samples

An experimental setup for performance of reverse mirage spectroscopy at CO2 laser wavelengths on liquid samples having high values of absorption coefficients is described. One and the same liquid is used as both the absorbing and deflecting medium. The Rosencwaig-Gersho theory has been applied, and the choice of experimental conditions that would enable determination of absorption coefficient β from the magnitude of photothermal signals measured at two different probe beam distances (probing locations) is discussed. The usefulness of this technique (essentially not inhibited by the requirements imposed on the sample's thickness) is tested on methanol having absorption coefficients β close to 300 cm−1 in the wavelength region covered by CO2 laser emission.

Acoustic Absorption Coefficients of the Surface of Laboratory Animals

1958 ◽  
Vol 30 (12) ◽  
pp. 1105-1111
Author(s):  
Eugene Ackerman ◽  
Robert W. Farwell ◽  
Fujio Oda ◽  
Adam Anthony
Keyword(s):  
Laboratory Animals ◽  
Acoustic Absorption ◽  
Absorption Coefficients

Determination of absorption coefficients of thick semiconductor samples using photoacoustic spectroscopy

1984 ◽  
Vol 23 (16) ◽  
pp. 2784 ◽  
Author(s):  
J. Fesquet ◽  
B. Girault ◽  
M. D. M. Razafindrandriatsimaniry
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Absorption Coefficients
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