Skip to main content

Research Repository

Advanced Search

Low frequency sound propagation in activated carbon

Bechwati, F; Avis, MR; Bull, DJ; Cox, TJ; Hargreaves, JA; Moser, D; Ross, DK; Umnova, O; Venegas, RG

Low frequency sound propagation in activated carbon Thumbnail


Authors

F Bechwati

MR Avis

DJ Bull

D Moser

DK Ross

O Umnova

RG Venegas



Abstract

Activated carbon can adsorb and desorb gas molecules onto and off its surface. Research has examined
whether this sorption affects low frequency sound waves, with pressures typical of audible
sound, interacting with granular activated carbon. Impedance tube measurements were undertaken
examining the resonant frequencies of Helmholtz resonators with different backing materials. It
was found that the addition of activated carbon increased the compliance of the backing volume.
The effect was observed up to the highest frequency measured (500 Hz), but was most significant at
lower frequencies (at higher frequencies another phenomenon can explain the behavior). An apparatus
was constructed to measure the effective porosity of the activated carbon as well as the number
of moles adsorbed at sound pressures between 104 and 118 dB and low frequencies between 20
and 55 Hz. Whilst the results were consistent with adsorption affecting sound propagation, other
phenomena cannot be ruled out. Measurements of sorption isotherms showed that additional energy
losses can be caused by water vapor condensing onto and then evaporating from the surface of the
material. However, the excess absorption measured for low frequency sound waves is primarily
caused by decreases in surface reactance rather than changes in surface resistance.

Citation

Bechwati, F., Avis, M., Bull, D., Cox, T., Hargreaves, J., Moser, D., …Venegas, R. (2012). Low frequency sound propagation in activated carbon. https://doi.org/10.1121/1.4725761

Journal Article Type Article
Publication Date Jan 1, 2012
Deposit Date Jul 25, 2012
Publicly Available Date Apr 5, 2016
Journal The Journal of the Acoustical Society of America (JASA)
Print ISSN 00014966
Peer Reviewed Peer Reviewed
Volume 132
Issue 1
Pages 239
DOI https://doi.org/10.1121/1.4725761
Publisher URL http://dx.doi.org/10.1121/1.4725761

Files






You might also like



Downloadable Citations