A method for detecting faults in plates includes the steps of: transmitting an acoustic signal towards the plate from a transmitting transducer, and receiving the acoustical signal from the plate in a receiving transducer. The receiving transducer is mounted at a distance from the transmitting transducer. The method includes the further steps of identifying zones of the plate wherein energy levels of the received signals are attenuated compared to other zones of the plate, and comparing the energy levels of the A.sub.2 and S.sub.3 guided Lamb modes in the received signals in the identified zones.

Methods, apparatus, and articles of manufacture are disclosed. An example pre-amplifier includes a demodulator to generate an oscillating signal having a measurement center frequency, combine an acoustic emission signal and the oscillating signal to generate a sideband acoustic emission signal, sample spectral data of the sideband acoustic emission signal at an intermediate center frequency in an intermediate frequency bandwidth, and generate demodulated acoustic emission data based on a mapping of the sampled spectral data to the measurement center frequency, the measurement center frequency different from the intermediate center frequency, and a transmitter to transmit the demodulated acoustic emission data to a computing device.

A fuel flow measuring system includes an ultrasonic fuel flow sensor. The fuel flow sensor includes a first transducer and a second transducer. The first transducer is excited at multiple different excitation frequencies and a voltage, an electric current, and a phase difference between the voltage and the electric current is sensed at the first transducer during excitation. Data points are generated based on the sensed readings and a model is fit to the data points to determine a complex impedance spectrum. The complex impedance spectrum indicates a range of excitation frequencies within a range of a peak resonance frequency of the first transducer. One or more characteristics of excitation signals directed to the second transducer are set based on the determined complex impedance spectrum. In this manner, the signal to noise ratio of ultrasonic signals emitted by the second transducer and received by the first transducer can be maximized.

An apparatus for monitoring mechanical integrity of an eye-safety component of an illuminator is disclosed. The apparatus comprises a transducer operable to create a vibration in the eye-safety component, a sensor operable to sense the vibration in the eye safety component and to output a signal representative of the sensed vibration, and a processor. The processor is operable to: monitor the signal from the sensor; determine if the signal comprises at least one parameter that falls outside of a pre-determined acceptable range, the pre-determined acceptable range being indicative of mechanical integrity of the eye-safety component; and initiate a safety action in response to a determination that the at least one parameter falls outside of the pre-determined acceptable range thereby indicating a loss of mechanical integrity.

Apparatus for performing multiple different measurements on a small specimen sample, enabling testing and diagnoses in real time at the point of care are described. The core of the apparatus includes an ultrasonic resonator cavity where acoustic resonances are used to determine the speed of sound and sound attenuation in a single droplet. Acoustic measurements are made in the reflection mode using electrical impedance of a small piezoelectric crystal transducer that operates in the thickness longitudinal mode. Combination of this technology with electromagnetic, electrical, and magnetic fields permits multiple types of measurements to be made using the same resonator cavity.

Non-limiting examples of the present disclosure relate to devices, systems and methods of manufacture for an exemplary waveguide usable for acoustic signal transmission for non-destructive evaluation (NDE) of a specimen (e.g., a wooden specimen) as well as apparatuses usable therewith. An exemplary waveguide comprises a mating portion for interfacing with a transducer horn of an ultrasonic transducer. The mating portion comprises at least a contact well configured to enable a connection between the transducer horn and the waveguide. The waveguide further comprises a body portion that comprises an upper body portion, that has a flat-faced distal end that is usable to establish contact with a surface of the specimen, and a lower body portion that is attached to and extends outwardly from the upper body portion and is further attached to the mating portion. Other technical examples are further described in the present disclosure.

A gas analyzer uses continuous sonic signals through a conduit to determine the composition of a gas in the conduit. A transmitting transducer drives sonic signals at a fixed frequency and a second transducer receives the sonic signals. The phase shift between two signals corresponds to the speed of sound through the gas and is related to the composition of the gas. The electronic versions of these signals are processed by lowering, or dividing, the fixed frequency which expands the range of phase shift measurement and allows the determination of an expanded range for the gas composition. In an ozone generation system, the gas analyzer is highly suitable for determining the composition of gases derived from air as a gas of known composition and a calibration point.

The disclosure discloses a stress gradient high-efficiency non-destructive detection system based on frequency domain calculation of broadband swept frequency signals, and a detection method thereof. The detection method includes: step 1: calibrating an LCR wave velocity of an object to be measured; step 2: calculating a starting frequency and a cut-off frequency of broadband swept frequency signals based on the LCR wave velocity of the object to be measured in the step 1 and a stress gradient measuring range in a depth direction of the object to be measured; step 3: converting phase delay to time delay information based on the phase delay of the starting frequency and the cut-off frequency in the step 2; and step 4: determining stresses of depths corresponding to different frequency components based on the time delay information in the step 3 to finally realize layer-by-layer scanning of stresses at different depths of the measured object. The disclosure is used to solve the problem of low stress gradient measuring accuracy, and realize the high-efficiency characterization of the stress gradient in the depth direction.

According to one embodiment, an inspection system of an embodiment includes one or more sensors. The one or more sensors detect second elastic waves emitted to the outside of a shaft-shaped inspection object due to first elastic waves propagating through the shaft-shaped inspection object. The one or more sensors are fixedly placed at positions away from the shaft-shaped inspection object and the directivity direction of the sensor is inclined at a predetermined angle with respect to an axial line of the shaft-shaped inspection object.

A method and a system to determine a gelation time of a substance in a container is disclosed. The system includes a container, a bubble generator arranged at a first end of the container, and a bubble sensor arranged at the second end of the container. The container holds a substance having a surface adjacent the second end. The bubble generator is configured to generate a bubble at the first end. The bubble sensor is configured to sense the bubble at the surface of the substance. The method includes releasing a gas into a first end of the container such that the gas bubbles rise from the first end of the container to a second end of the container, sensing the released bubbles, determining an absence of a bubble released by the bubble generator at the bubble sensor, and determining a gelation time based on a number of detected bubbles.