@article{PATENT,
      recid = {9094},
      title = {Method for measuring liquid viscosity and ultrasonic  viscometer},
      number = {PATENT},
      month = {Nov},
      year = {1994},
      abstract = {An ultrasonic viscometer and method for measuring fluid  viscosity are provided. Ultrasonic shear and longitudinal  waves are generated and coupled to the fluid. Reflections  from the generated ultrasonic shear and longitudinal waves  are detected. Phase velocity of the fluid is determined  responsive to the detected ultrasonic longitudinal waves  reflections. Viscosity of the fluid is determined  responsive to the detected ultrasonic shear waves  reflections. Unique features of the ultrasonic viscometer  include the use of a two-interface fluid and air transducer  wedge to measure relative signal change and to enable self  calibration and the use of a ratio of reflection  coefficients for two different frequencies to compensate  for environmental changes, such as temperature.},
      url = {http://knowledge.uchicago.edu/record/9094},
}