A method for inspecting a fastened structure, the fastened structure having at least one structural member defining a bore therein and a mechanical fastener received in the bore, includes applying acoustic energy to the fastened structure, the acoustic energy being applied over a plurality of frequencies, measuring a response of the fastened structure across at least two frequencies of the plurality of frequencies, and comparing the response of the fastened structure at the at least two frequencies of the plurality of frequencies to predefined values for the at least two frequencies of the plurality of frequencies to determine whether an out-of-tolerance condition is present.

A piezoelectric actuator includes: a vibrating plate including a first surface configured to close an opening provided in a substrate and also including a second surface including a plurality of piezoelectric elements; a suppressing portion configured to suppress vibration of the vibrating plate; and a plurality of walls sticking out into the opening from the first surface, in which, when an active portion of a piezoelectric element is set as a portion where a first electrode, a piezoelectric layer, and a second electrode overlap, the walls are provided between adjacent active portions in plan view from a direction in which the first electrode, the piezoelectric layer, and the second electrode are stacked, and a distance between adjacent walls is longer than a distance between adjacent active portions in a plane perpendicular to the stacking direction.

Embodiments disclosed herein include diagnostic substrates and methods of using the diagnostic substrates to extract plasma parameters. In an embodiment, a diagnostic substrate comprises a substrate and an array of resonators across the substrate. In an embodiment, the array of resonators comprises at least a first resonator with a first structure and a second resonator with a second structure. In an embodiment, the first structure is different than the second structure.

A concentration measuring instrument includes a piezoelectric vibrator transmitting an ultrasonic wave into a solution contained in a cavity and detecting the ultrasonic wave reflected, a temperature sensor measuring a temperature of the solution, a drive circuit generating a drive signal driving the piezoelectric vibrator, a phase comparator performing a phase comparison between the drive signal and a detection signal, a frequency setting circuit making the drive circuit generate drive signals having sequentially different frequencies and monitoring a phase comparison result to detect a resonant frequency, and a Phase Locked Loop (PLL) circuit making a frequency of the drive signal follow the detected resonant frequency. A microcomputer determines a concentration of a solute in the solution on a basis of the frequency of the drive signal while the PLL circuit is being operated and a result of a temperature measurement by the temperature sensor.

A resonance detection system includes a vibration simulation mechanism and a vibration audio analysis device. The vibration simulation mechanism includes a mechanism body that accommodates a peripheral interface device. The vibration simulation mechanism generates a vibration wave to the peripheral interface device. The peripheral interface device generates a vibration audio signal in response to the vibration wave. The vibration audio analysis device is electrically connected with the vibration simulation mechanism. After the vibration audio signal is inputted into the vibration audio analysis device, the vibration audio analysis device judges whether there is an abnormal resonance phenomenon in the vibration audio signal. The vibration simulation mechanism further includes a patch-type audio collector, which is electrically connected with the vibration audio analysis device. The patch-type audio collector is attached on the mechanism body containing the peripheral interface device. The vibration audio signal is collected by the patch-type audio collector.

A method for analyzing dynamic mode change of an anisotropic material includes performing modal analysis of a first physical force applied to an isotropic material specimen and a first vibration signal collected from the isotropic material specimen, acquiring a first modal parameter of the isotropic material specimen, based on the modal analysis result, performing modal analysis of a second physical force applied to the anisotropic material specimen and a second vibration signal collected from the anisotropic material specimen, acquiring a second modal parameter of the anisotropic material specimen, based on the modal analysis result, acquiring a modal assurance criterion (MAC) for each mode of the anisotropic material specimen, based on the first and second modal parameters, and acquiring each similar mode of the anisotropic material specimen to each mode of the isotropic material specimen.

A sensor probe for analysis of a fluid includes a base, and a pair of electrodes and a pair of shield members protruding from the base for insertion into the fluid. The electrodes have electrical oscillations generated therein for measurement of electromagnetic properties of the fluid, such as permittivity. The shield members are disposed outside the electrodes and have a dual purpose of electromagnetically shielding the electrodes and having vibrations generated therein for measurement of physical parameters of the fluid, such as density or viscosity. Thus, the single sensor probe can provide measurements of both electromagnetic properties and physical properties of the fluid.

A sound source device and a signal receiver are disposed at first and second ports of a target object, respectively. A sound of a specific frequency of the sound source device is introduced into the target object to generate a resonant sound wave. A computer simulates a signal generated when the resonant sound wave is received by the signal receiver and regarding the signal as reference information. The reference information comprises first data having characteristics of the resonant sound wave, and data having features of an imaginary defect formed on the target object. The features of the imaginary defect correspond to the characteristics of the resonant sound wave. When the target object has a real defect, the sound of the specific frequency of the sound source device is introduced into the target object. Features of the real defect are derived by comparing the first data with the second data.

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 and system for ultrasonic testing of adhesion within a sample, which provides ultrasonic bursts of different frequencies to the sample and maintains a predetermined phase difference between echoes returned from the sample and representative reference signals of the bursts supplied to the sample until a spectrum of the phase differences versus frequency is obtained and from which properties of the adhesion at an interface reflecting the echoes are derivable.