A transducer system. The system comprises a transducer and circuitry for applying an excitation waveform to excite the transducer during an excitation period. The circuitry for applying has: (i) circuitry for applying a first waveform at a first frequency; and (ii) circuitry for applying a second waveform at a second frequency differing from the first frequency.

A transducer system. The system comprises a transducer and circuitry for applying an excitation waveform to excite the transducer during an excitation period. The circuitry for applying has: (i) circuitry for applying a first waveform at a first frequency; and (ii) circuitry for applying a second waveform at a second frequency differing from the first frequency.

A method for real time crush testing of proppants including loading proppant into an apparatus comprising: a body with a chamber to accept a piston and proppant; a pressure piston; a pressure transducer located in the bottom of the chamber; and a displacement sensor; compressing the proppant with the pressure; calculating the amount of proppant material in the proppant pack; increasing pressure on the proppant pack until the sample is crushed; calculating proppant strength from at least the displacement sensor data. An apparatus includes a body with a chamber to accept a piston and proppant; a pressure piston; a pressure transducer located in the bottom of the chamber; and a displacement sensor.

A method for real time crush testing of proppants including loading proppant into an apparatus comprising: a body with a chamber to accept a piston and proppant; a pressure piston; a pressure transducer located in the bottom of the chamber; and a displacement sensor; compressing the proppant with the pressure; calculating the amount of proppant material in the proppant pack; increasing pressure on the proppant pack until the sample is crushed; calculating proppant strength from at least the displacement sensor data. An apparatus includes a body with a chamber to accept a piston and proppant; a pressure piston; a pressure transducer located in the bottom of the chamber; and a displacement sensor.

The disclosure relates to methods and apparatus for identifying rheological properties of liquids from acoustic signals generated by liquid flow through a pipe. Example embodiments include a method of identifying a rheological property of a liquid flowing in a pipe (101), the method comprising: detecting an acoustic signal generated by the liquid flowing in the pipe using a sensor (105) attached to a rod (104) extending from a wall of the pipe (101) into the liquid; sampling the acoustic signal to provide a sampled acoustic signal; transforming the sampled acoustic signal to generate a sampled frequency spectrum; correlating the sampled frequency spectrum with a stored frequency spectrum from a database of stored frequency spectra of liquids having predetermined rheological properties; and identifying a rheological property of the liquid based on the stored frequency spectrum.

The disclosure relates to methods and apparatus for identifying rheological properties of liquids from acoustic signals generated by liquid flow through a pipe. Example embodiments include a method of identifying a rheological property of a liquid flowing in a pipe (101), the method comprising: detecting an acoustic signal generated by the liquid flowing in the pipe using a sensor (105) attached to a rod (104) extending from a wall of the pipe (101) into the liquid; sampling the acoustic signal to provide a sampled acoustic signal; transforming the sampled acoustic signal to generate a sampled frequency spectrum; correlating the sampled frequency spectrum with a stored frequency spectrum from a database of stored frequency spectra of liquids having predetermined rheological properties; and identifying a rheological property of the liquid based on the stored frequency spectrum.

Because of the increase of the obesity related diseases, it is desirable to be able to detect a fatty liver and quantify the content in fat for the fatty liver. Known methods are biopsy and magnetic resonance imaging. However, biopsy is an invasive method and magnetic resonance imaging is a complicated method to carry out. The inventors propose a new ultrasonic method which is more compliant with a regular control of the content in fat for the fatty liver for a subject. This method notably relies on a smart exploitation of the coherence properties of ultrasound pulses applied to the liver. This method has already been validated on sane subjects as providing accurate measurements, notably for fat content.

This application relates to an apparatus and method for detecting a microcrack using orthogonality analysis of a mode shape vector and a principal plane in a resonance point. The apparatus may include a measurement unit comprising multiple sensors and configured to measure whether a crack exists at a measurement target, and an analysis unit configured to determine whether a crack exists, on the basis of measurement values of the respective sensors. The measurement unit includes a fixing jig configured to fix the measurement target, an excitation means configured to apply a predetermined impact to the measurement target, and multiple acceleration sensors attached at predetermined locations on the measurement target. The analysis unit may further calculate frequency responses of the measurement target to the impact applied by the excitation means, and determine whether a crack exists by analyzing the number of resonance points and independence of the resonance points.

Disclosed is a method of determining a characteristic of a measurement intermediate layer (220) in a multilayer structure (200) using an ultrasonic transducer (100), wherein the multilayer structure (200) includes a first layer (210), a measurement intermediate layer (220) and a third layer (230) in series abutment. The method comprises transmitting a measurement ultrasonic signal into the first layer (210) towards the measurement intermediate layer (22)0, measuring a measurement reflection of the measurement ultrasonic signal from the multilayer structure (200), determining, using the measurement reflection, a measured frequency response of the measurement intermediate layer (220), determining a plurality of modelled frequency responses of the measurement intermediate layer (220), comparing the measured frequency response to the plurality of modelled frequency responses, and determining the characteristic of the measurement intermediate layer (220) based on the comparison of the measured frequency response and the plurality of modelled frequency responses.

Disclosed is a method of determining a characteristic of a measurement intermediate layer (220) in a multilayer structure (200) using an ultrasonic transducer (100), wherein the multilayer structure (200) includes a first layer (210), a measurement intermediate layer (220) and a third layer (230) in series abutment. The method comprises transmitting a measurement ultrasonic signal into the first layer (210) towards the measurement intermediate layer (22)0, measuring a measurement reflection of the measurement ultrasonic signal from the multilayer structure (200), determining, using the measurement reflection, a measured frequency response of the measurement intermediate layer (220), determining a plurality of modelled frequency responses of the measurement intermediate layer (220), comparing the measured frequency response to the plurality of modelled frequency responses, and determining the characteristic of the measurement intermediate layer (220) based on the comparison of the measured frequency response and the plurality of modelled frequency responses.