This method comprises: generating, only using the device, a low-frequency signal that makes the structure vibrate, generating a high-frequency signal in the structure, measuring a vibratory signal caused by the generated low-frequency and high-frequency signals at the same time then adaptively re-sampling these measurements to obtain a re-sampled vibratory signal the power spectrum of which comprises: a first frequency range [u.sub.BFmin; u.sub.BFmax] of width larger than 5 Hz that contains 95% of the power of the low-frequency signal, a second frequency range [u.sub.HFmin; u.sub.HFmax] of width systematically smaller than u.sub.BFmin that contains 95% of the power of the low-frequency signal, signaling a defect in the structure if an additional power lobe is detected outside of the ranges [u.sub.BFmin; u.sub.BFmax] and [u.sub.HFmin; u.sub.HFmax].

According to one embodiment, an ultrasonic probe includes a first vibrating element and a second vibrating element. The first vibrating element is configured to vibrate at a first peak frequency. An intensity of a vibration of the first vibrating element is highest at the first peak frequency. The second vibrating element is configured to vibrate at a second peak frequency lower than the first peak frequency. An intensity of a vibration of the second vibrating element is highest at the second peak frequency.

An exciter (11, 12) induces an elastic wave in a test object by sequentially giving the object multiple kinds of vibrations having different frequencies. An illuminator (13, 14) performs stroboscopic illumination on a measurement area on the surface of the object. A displacement measurer (15) controls the timing of the stroboscopic illumination with respect to the phase of the elastic wave for each kind of vibration to perform a batch measurement of the displacements, in the off-plane direction of the surface, of the points within the measurement area at least at three different phases of the elastic wave, using speckle interferometry or speckle-shearing interferometry.

The embodiments disclosed herein relate to the examination of gemstones including diamonds, both cut/polished and rough, using the technology of Resonant Ultrasound Spectroscopy. The resonant frequencies are obtained by mechanically causing the stone to vibrate using a swept sine oscillator, sensing the resonance vibrations, and displaying the spectrum to yield a pattern describing the stone. The resonance fingerprints can be used to both track an individual stone to verify its integrity or to grade a rough stone to establish potential value.

To detect air in a fluid delivery line of an infusion system, infusion fluid is pumped through a fluid delivery line adjacent to at least one sensor. A signal is transmitted and received using the at least one sensor into and from the fluid delivery line. The at least one sensor is operated, using at least one processor, at a modified frequency which is different than a resonant frequency of the at least one sensor to reduce an amplitude of an output of the signal transmitted from the at least one sensor to a level which is lower than a saturation level of the analog-to-digital converter to avoid over-saturating the analog-to-digital converter. The signal received by the at least one sensor is converted from analog to digital using an analog-to-digital converter. The at least one processor determines whether air is in the fluid delivery line based on the converted digital signal.

There is provided a method for determining material properties in an active acoustic spectroscopy system, the method comprising: acquiring a multidimensional acoustic spectrum from a material in a container using acoustic spectroscopy; reducing the dimensionality of the acoustic spectrum using a mathematical dimensionality reduction method, thereby forming a reduced acoustic spectrum describing a material state; and determining if the material state belongs to a predetermined material state cluster. There is also provided a system for performing the described method.

The present document relates to a heterodyne scanning probe microscopy (SPM) method for subsurface imaging, and includes: applying an acoustic input signal to a sample and sensing an acoustic output signal using a probe. The acoustic input signal comprises a plurality of signal components at unique frequencies, including a carrier frequency and at least two excitation frequencies. The carrier frequency and the excitation frequencies form a group of frequencies, which are distributed with an equal difference frequency between each two subsequent frequencies of the group. The difference frequency is below a sensitivity threshold frequency of the cantilever for enabling sensing of the acoustic output signal. The document also describes an SPM system.

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, such as a notebook computer key input mechanical structure. The vibration simulation mechanism generates a vibration wave to the peripheral interface device generates a vibration audio signal in response to the vibration wave. The vibration simulation mechanism further includes a patch-type audio collector, such as a miniature auscultation radio patch, which is 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. The vibration audio analysis device judges whether there is an abnormal resonance phenomenon in the vibration auto signal, which may be used for fabrication quality control of peripheral interface devices.

A defect inspection device (100) includes an excitation unit that excites an elastic wave, an irradiation unit (2) that applies laser lights, a measurement unit (3) that measures the interfered laser lights, and a control unit that acquires vibration state information which is information about a state of the elastic wave excited in an inspection target (P) for a plurality of frequencies by changing a frequency of excitation vibration caused by the excitation unit in order to excite the elastic wave in the inspection target (P), and extracts recommended frequencies (F) recommended for inspecting a defect of the inspection target (P) from among the plurality of frequencies based on the acquired vibration state information for the plurality of frequencies.

This disclosure relates to the monitoring and detection of corrosion and/or erosion of pipes, vessels, and other components in an industrial facility. The monitoring system may comprise of an arrangement of guided wave (GW) transducers and a longitudinal wave (LW) transducer affixed to the piping component to collectively measure for localized corrosion of the piping component without necessarily requiring a thickness map. The monitoring system may use an intelligent amplified multiplexer/switch to control the operation of the transducers that may be controlled and operated to generate waves in the kilohertz range and megahertz range with the same hardware.