A surface acoustic wave (SAW) sensor includes a surface acoustic wave material and a comb-teeth electrode. The surface acoustic wave material is to be arranged at a place where the surface acoustic wave material is distorted by physical quantity such as stress. The comb-teeth electrode is arranged on the surface of the surface acoustic wave material to excite a surface acoustic wave to the surface acoustic wave material. The surface acoustic wave material has a sapphire board and a ScAlN film arranged on a surface of the sapphire board.

In the present invention a controllable acoustic source (14) in connection with the process fluid (10) emits a signal (18) into the fluid (10), consisting of a suspension of particles (12), being volumes of gas, liquid or solid phase. The controllable acoustic signal (18) is allowed to interact, with the particles (12), and the acoustic (pressure) signals (22) resulting from such an interaction is measured preferably via a sensor (24). A spectrum is measured. The spectrum is used to predict properties, content and/or size of the particles (12) and/or used to control a process in which the process fluid (10) participates. The prediction is performed in the view of the control of the acoustic source (14). The used acoustic signal has preferably a frequency below 20 kHz.

An ultrasonic sensor which includes a substrate where an opening section is formed, a vibration plate that is provided on the substrate so as to close the opening section, and a piezoelectric element that is layered on a surface of the vibration plate on an opposite side to the opening section and includes a first electrode, a piezoelectric element, and a second electrode, includes a reflection layer that is provided in a space around the piezoelectric element on the surface of the vibration plate on an opposite side to the opening section, to reflect other ultrasonic waves which are transmitted in a different direction from a transmitted ultrasonic wave transmitted to a measuring target side on an interface between the piezoelectric element and the reflection layer, and has a thickness so as to superimpose other ultrasonic waves on the transmitted ultrasonic wave.

A photoacoustic photon meter includes: a photoacoustic generative array including carbon nanotubes disposed in a photoacoustic generating pattern, such that the carbon nanotubes: receive photons comprising optical energy, and produce thermal energy from the optical energy; and a superstratum including a thermally expandable elastomer on which the photoacoustic generative array is fixedly disposed in position on the superstratum to spatially conserve the photoacoustic generating pattern, and such that the superstratum: is optically transparent to the photons; receives the thermal energy from the photoacoustic generative array; expands and contracts in response to receipt of the thermal energy; and produces photoacoustic pressure waves in response to the expansion and contraction, the photoacoustic pressure waves including a photoacoustic intensity and photoacoustic frequency that are based upon an amount of optical pressure applied to the carbon nanotubes by the photons, a spatial photon fluence of the photons, or a spectral photon fluence of photons.

An environmental condition may be measured with a sensor (10) including a wire (20) having an ultrasonic signal transmission characteristic that varies in response to the environmental condition by sensing ultrasonic energy propagated through the wire using multiple types of propagation, and separating an effect of temperature on the wire from an effect of strain on the wire using the sensed ultrasonic energy propagated through the wire using the multiple types of propagation. A positive feedback loop may be used to excite the wire such that strain in the wire is based upon a sensed resonant frequency, while a square wave with a controlled duty cycle may be used to excite the wire at multiple excitation frequencies. A phase matched cone (200, 210) may be used to couple ultrasonic energy between a waveguide wire (202, 212) and a transducer (204, 214).

An air data system includes an air data probe and a surface acoustic wave (SAW) sensor attached to the air data probe for detecting particulate accumulation. The air data probe includes a probe head, a strut connected to the head, and a mounting plate connected to the strut. The probe head has an inlet, an interior surface extending from the inlet, and an exterior surface extending from the inlet.

A pressure monitoring system for a compressed fluid source may comprise a surface acoustic wave sensor and a controller operably coupled to the surface acoustic wave sensor. The controller may be configured to send a first radio frequency signal to the surface acoustic wave sensor, receive a second radio frequency signal from the surface acoustic wave sensor, and determine a pressure of the compressed fluid source based on the first radio frequency signal and the second radio frequency signal.

A quartz pressure sensor that resonates in the thickness-shear mode can include a center resonator structure and first and second caps joined to the center resonator structure by bond joints. Each bond joint is comprised of a sealing glass having thickness less than 0.0012 inches (˜30 μm) and a melting point less than 573° C. The quartz pressure sensor can additionally include an inner diameter edge feature formed between the interior sidewall in the joint sidewall of the caps that reduces stresses at the bond joints and/or a high stress point in the cap bore.

A system to determine a temperature corrected pressure of a medium in a pressure transducer is disclosed. The system comprises a first circuitry to obtain a first value related to a vibration frequency of the vibration of a pressure sensitive vibration member; a second circuity to obtain a second value related to a vibration amplitude of the vibration of the vibration member; and a third circuity to use the first value and the second value to determine the temperature corrected pressure of the medium based on a predetermined relationship between the vibration frequency and the vibration amplitude.

The present invention discloses an apparatus and a method for evaluating properties of a temporary plugging agent based on acoustic emission, wherein the apparatus includes a fracturing machine, an acoustic emission sensor and an acoustic emission analyzer, wherein the fracturing machine is configured to load a sample when oil pressure is stable and remains unchanged in a fracture of the sample, a real fracturing condition being simulated for the sample, and oil being pumped in and a temporary plugging agent being placed into the fracture; the acoustic emission sensor is configured to detect an acoustic wave signal emitted by the sample when the fracturing machine loads the sample; and the acoustic emission analyzer is connected to the acoustic emission sensor and configured to determine that the temporary plugging agent is fractured when a fracture signal occurs in the acoustic wave signal. The present invention can obtain the fracture information of the sample without disturbing the normal experimental process and experimental results, and the experimental measurement results are more practical.