Frequency Spectrum of Laser Ultrasonic Signals from Fibers and Particles Suspensions

• Autorzy: Zhao Z. , Törmänen M. , Myllylä R.
• Języki publikacji: EN

Abstrakty

EN

This paper studied fiber and particle suspensions using pulsed laser-induced ultrasonic waves. By analyzing the power spectrum of these wide frequency ultrasonic waves propagating through different suspensions, the paper demonstrates that acoustic attenuation caused by fibers has a larger effect on high frequency than on low frequency components. Since this phenomenon was not observed in solutions containing fines and particles, it is useful for determining a solution's fiber consistency and for measuring fiber and fines fractions in paper pulp. Moreover, the experiment also showed that, relative to measuring attenuation amplitude, the measured power spectrum is less affected by fiber flock, micro air bubbles, acoustic coupling and temperatures.

Słowa kluczowe

EN

pulsed photoacoustic; power spectrum; suspension; paper pulp

• Wydawca: Silesian Division of Polish Acoustical Society
• Czasopismo: Molecular and Quantum Acoustics
• Rocznik: 2006
• Tom: Vol. 27
• Strony: 319--326
• Opis fizyczny: Bibliogr. 5 poz., rys.

Twórcy

autor

Zhao Z.

autor

Törmänen M.

autor

Myllylä R.

• Department of Electrical and Information Engineering and Infotech Oulu, University of Oulu, P.O.Box 4500, 90014 University of Oulu, Finland,

Bibliografia

• 1.J. Saarela, M. Törmänen, and R. Myllylä, Meas. Sci. Technol. 14, 180 (2003).
• 2.M. Törmänen, J. Niemi, T. Löfqvist, and R. Myllylä, Meas. Sci. Technol. 17, 695 (2006).
• 3.Z. Zhao, M. Törmänen, and R. Myllylä, Meas. Sci. Technol. 128 (2006).
• 4.H. Medwin, Ultrasonics 15, 7 (1977).
• 5.T. Löfqvist, Proc. IEEE Ultrasonics Symp. 841 (1997).