Sound absorption study of raw and expanded particulate vermiculites
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Expanded and raw vermiculite minerals were studied for their ability to absorb sound. Phase and structural characterization of the investigated vermiculites was found similar for both types, while morphology and surface properties vary. Sound waves reflect in wedge-like structure and get minimized, and later are absorbed totally. We found that thanks to porous character of expanded vermiculite the principle of absorption of sound into layered vermiculite morphology is analogous to principle of sound minimization in “anechoic chambers.” It was found in this study that the best sound damping properties of the investigated vermiculites were in general obtained at higher powder bed heights and higher excitation frequencies.
KeywordsSound Speed Sound Absorption Anechoic Chamber Sound Absorption Coefficient High Excitation Frequency
This study was supported by The Ministry of Education, Youth and Sports from the National Programme of Sustainability (NPU II) project “IT4Innovations excellence in science”—LQ1602 and by the MSMT (SP2016/65 and SP2016/66). Authors thank to P. Peikertová, Ph.D. and S. Študentová from VŠB-Technical University of Ostrava for their contributions in the field of vermiculite characterization, FTIR and porosimetry measurement.
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