title: A novel phase locked cavity resonator for B/A measurements in fluids
abstract: A new technique for the measurement in fluids of the acoustic non-linearity parameter B/A is presented, together with measured B/A values for several fluids. The non-linearity parameter is measured by phase locking radial modes within a PZT cylinder. The system, which implements the isentropic phase technique, uses continuous wave phase locking to measure the change in sound velocity that is typically associated with a change in ambient pressure under constant entropy. The method provides a means of measuring B/A in vitro both accurately and simply without the typical problems involved in time-of-flight systems. Fluid samples can remain small due to the nature of the cavity resonator, so the system is well suited to small volume, biological samples.
authors.affiliation: Department of Electrical Engineering, University of Cape Town, Rondebosch, South Africa. jdavies@eleceng.uct.ac.za
authors.initials: JR
authors.lastname: Davies
authors.initials: J
authors.lastname: Tapson
authors.initials: BJ
authors.lastname: Mortimer