title: System for determination of ultrasonic wave speeds and their temperature dependence in liquids and in vitro tissues.
abstract: An interferometric technique capable of accurately measuring wave speed in liquids is reported. The hardware is adapted from a design to measure nonlinear responses of biological tissues to pressure changes (pressure derivatives) and temperature changes (temperature derivatives). It is used with the highly sensitive variable frequency pulsed phase-locked loop (VFPPLL) instrument. The system uses well-understood and well-characterized components and systems. The apparatus covers a temperature range from below 5 degrees C to above 45 degrees C. The system with the high-sensitivity VFPPLL is capable of measurement of wave speed to an uncertainty of less than 0.1%, and changes in wave speed to better than 0.001%. The transducer is an undamped temperature-characterized PZT-5A 500-kHz plate, whose output is corrected for off-resonance operation and for diffraction effects. To test the accuracy of the technique, measurement of ultrasonic compressional wave speed in water at temperatures from 10 degrees C to 45 degrees C are reported, with an estimated uncertainty of 0.07% and a temperature uncertainty of 0.15 degrees C. The agreement between mean values and literature values is better than 0.05%.
authors.affiliation: NASA-Langley Research Center, Hampton, Virginia 23681-2199, USA.
authors.forename: William T
authors.initials: WT
authors.lastname: Yost
authors.forename: Brandon R
authors.initials: BR
authors.lastname: Macias
authors.forename: Peihong
authors.initials: P
authors.lastname: Cao
authors.forename: Alan R
authors.initials: AR
authors.lastname: Hargens
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Ueno
mesh_terms: D000162:Acoustics; D006801:Humans; D009991:Oscillometry; D012212:Rheology; D012815:Signal Processing, Computer-Assisted; D013696:Temperature; D014159:Transducers; D014463:Ultrasonography; D014867:Water
chemical_list: D014867:Water