Abstract: A method and apparatus for resolving individual signals in detector output data are disclosed. One inventive aspect includes a processing circuit configured to receive detector output data wherein the detector output data may be stepped data or non-stepped data; transform the detector output data to produce stepped data wherein the detector output data is received as non-stepped data; detect at least one signal at least partially based on the stepped data; and estimate a parameter associated with the signal, wherein estimating the parameter may preferably comprise estimating a signal energy or signal time of arrival associated with the signal.

Abstract: A machine bearing disposed on a rotatable member, such as may be present on a vehicle, is described. A method for monitoring a state of health of the machine bearing includes monitoring, via a microphone, an acoustic signal, and coincidently determining a rotational speed of the rotatable member associated with the machine bearing. The sound spectrum is correlated to the rotational speed of the rotating member, and a time-frequency analysis is executed to determine a sound spectrum. The sound spectrum is transformed to a residual spectrum. A first feature associated with a first frequency band and a second feature associated with a second frequency band are extracted from the residual spectrum. The state of health associated with the machine bearing is detected based upon the first and second features, and is communicated to a second controller.

Abstract: According to an embodiment, an apparatus for detecting a characteristic of a pump includes: a housing having a first planar surface and a second planar surface opposite the first planar surface, a mount structure located on the second planar surface, wherein the mount structure is configured to facilitate attachment of the apparatus on an external surface of the triplex pump, and wherein the mount structure avoids penetrating an inside surface of the triplex pump. Advantageously, apparatus is a non-invasive device and does not involve modifications to the pump nor opening the lid of the pump.

Abstract: A method for measuring fracture characteristics of adhesive polymeric material comprises: (i) bonding a sample to a rigid substrate; (ii) cooling the sample from a first temperature to a second temperature such that thermally-induced stresses are generated within the sample, wherein the thermally-induced stresses generate an inward-growing three-dimensional spiral crack within the sample; (iii) detecting, by three or more AE piezoelectric sensors, mechanical transient waves generated during development of the inward-growing three-dimensional spiral crack within the sample and determining the accurate 3D geometry of the spiral using source location technique; (iv) visualizing the two-dimensional spiral cracking pattern deposited on a surface of the rigid substrate and measuring the precise width of the crack; (v) determining, using the detected mechanical waves and the visualized deposited sample, AE-based fracture characteristics of the sample; and (vi) reporting the determined one or more fracture characteri

Abstract: A machine tool includes: a main spindle that holds a work piece; a tool holding unit that holds a tool for processing the work piece; a detection unit that detects vibration generated during processing of the work piece; and a processor that controls machining of the work piece performed by the tool, in which the processor compares a detected value detected by the detection unit with a predefined threshold value, interrupts the machining by releasing contact between the work piece and the tool at time of generation of chatter vibration or when there is a sign of the generation of the chatter vibration in which the detected value exceeds the threshold value, and analyzes the chatter vibration while the machining is being interrupted on basis of the detected value detected by the detection unit before the interruption.

Abstract: Integrated acoustic emission transducer apparatus and methods are described. An example integrated external preamplifier device includes a data extractor, a process variable determiner, a status indication determiner, and a presentation device. The integrated external preamplifier device receives an acoustic emission signal generated via an acoustic emission sensor operatively coupled to the integrated external preamplifier device. The data extractor extracts signal data from the acoustic emission signal. The process variable determiner determines process variable data based on the extracted signal data. The process variable data includes at least one of flow rate data, flow capacity data, flow area data, flow velocity data, mass accumulation data, or volume accumulation data. The status indication determiner determines status indication data based on the process variable data.

Abstract: Bandwidth-selectable acoustic emission apparatus and methods for transmitting time-averaged signal data are described. An example apparatus includes an integrated external preamplifier device having a bandwidth-selectable analog filter and a data extractor. The integrated external preamplifier device is to receive an analog acoustic emission signal generated via an acoustic emission sensor operatively coupled to the integrated external preamplifier device. The bandwidth-selectable analog filter is to filter the analog acoustic emission signal based on a software-programmed bandwidth to generate a filtered analog acoustic emission signal. The data extractor is to extract a time-averaged analog signal from the filtered analog acoustic emission signal, and to transmit the time-averaged analog signal from the integrated external preamplifier device to an external data acquisition system.

Abstract: A rig management system is disclosed. The rig management system may gather, from a set of sensors, data that includes: vibration data related to vibration of a valve associated with a pump of a hydraulic fracturing rig during operation of the pump, and pump speed data related to a speed of the pump during operation of the pump. The rig management system may process the data to identify a trend related to the vibration data, wherein the vibration data has been normalized based on the pump speed data. The rig management system may determine a remaining useful life of the valve based on the trend and threshold data that identifies a set of thresholds related to the vibration of the valve. The rig management system may determine that the remaining useful life satisfies a threshold. The rig management system may schedule an operation to be performed on the valve.

Abstract: A state monitoring system for monitoring state of a gear device having a plurality of gear pairs has a meshing frequency determination device. The meshing frequency determination device includes a maximum-peak-amplitude calculation unit that calculates a maximum peak amplitude from a detected meshing vibration, in estimated frequency ranges and a set harmonic region, and selects such estimated frequencies that a difference in maximum peak amplitude between a plurality of estimated frequency ranges, is less than or equal to a predetermined multiple, and a meshing frequency determination unit that determines an estimated frequency having a total value of maximum peak amplitudes calculated in the plurality of estimated frequency ranges, within a predetermined time, being the k-th (k is a natural number) greatest among the selected estimated frequencies, as a meshing frequency of a gear pair having the k-th highest tooth surface speed.

Abstract: The present disclosure discloses a detecting device and method for acoustic emission on high-frequency motion rubbing pair surface. A linear reciprocating slide system with high efficiency and high conductivity is designed based on the method. Reciprocating linear slide system is the main structure of the detection device which is is composed of probe plate, tight clips, vacuum cover, slip wire and insulation box. The reciprocating slide solves the problem of data distortion caused by high frequency jitter when connecting ordinary data lines, and can realize stable and reliable connection between high frequency reciprocating rubbing experiment and acoustic emission detection equipment. The acoustic emission probe on the surface of rubbing pair connects with the preamplifier by linear reciprocating slide.

Abstract: Circuitry for determining the direction of incidence of an acoustic signal in an integrated circuit. An electronic circuit includes a packaged integrated circuit. The packaged integrated circuit includes a die. The die includes a plurality of acoustic transducers spaced apart on the die, and a measurement circuit. The plurality of acoustic transducers includes at least a first acoustic transducer and a second acoustic transducer. The measurement circuit is coupled to at least the first acoustic transducer and the second acoustic transducer. The measurement circuit is configured to determine for the first acoustic transducer, a first time at which the first acoustic transducer detects an acoustic signal propagating in the die; and determine for the second acoustic transducer, a second time at which the second acoustic transducer detects the acoustic signal propagating in the die.

Abstract: A method for determining a quality of a friction stir welded seam is described. The method involves applying an impact to a welded plate and comparing its damping capacity with the damping capacity of a geometrically equivalent defect-free plate. Damping capacities that differ by a small percent difference indicate that the welded plate is also defect-free. This method is particularly advantageous when dealing with small defects, which produce miniscule changes in natural frequency which may not be measureable.

Abstract: A device for evaluating the condition of a wooden structure, including: a shaft; a distance sensor coupled to the shaft; and an image capture device coupled to the shaft, the distance sensor being configured to measure a location of the image capture device in the wooden structure.

Abstract: A method and apparatus of condition monitoring and detection of vibration generated from at least two different sources using a single sensor/transducer is provided. The method and apparatus provides switchably adapting signal processing, such as amplification and frequency filtering, to one at a time of the at least two different signal sources. An example of which is vibration sources. This adapts the analogue signal from the sensor/transducer to the analogue to digital converter and any further optional analogue signal processing, so that it is possible to maximize use of available dynamic range of these and without any saturation of these. Suitably, the signal processing to analyze the vibration signals is also appropriately adapted to the vibration source in question.

Abstract: Methods and systems for detecting pests, such as termites, in living organisms, such as trees. Certain embodiments of the current invention utilize time domain reflectometry to detect the pests. Other embodiments of the current invention utilize microwave-coupled transmission spectrometry antenna array transmitters, and receivers to detect the pests.

Abstract: Process to monitor unwanted formation of a polymer, having internal mechanical strain, wherein said formation of polymer generates acoustic emissions due to the sudden break of the polymer, wherein the number of said acoustic emissions increases over time when there is formation of said unwanted polymer formation, wherein said acoustic emissions is detected by a resonant piezo electric transducer having a resonant frequency centred on the second harmonic of said acoustic emission.

Abstract: A method and an apparatus for verifying compliance with a dental appliance therapy for a human patient is described. At least one parameter of a dental appliance worn by the human patient is periodically measured and compliance with the dental appliance therapy is determined by performing a spectral analysis of the measured parameter.

Abstract: Provided is a state diagnosis system, which is applied to a rolling guide device in which a moving member including an endless circulation path for rolling elements is freely movable along a track member, and which is configured to appropriately recognize a state of a rolling surface of the track member. The state diagnosis system includes: a sensor configured to detect a physical quantity exhibited when the moving member is moving along the track member; a signal processing unit configured to process an output signal from the sensor to output analysis data; and a determination processing unit configured to compare the analysis data with threshold value data to determine whether or not the rolling guide device has an abnormality.

Abstract: Methods and systems for conducting downhole operations including collecting downhole dynamic event data using a downhole tool, wherein the downhole dynamic event data is time-domain data, processing the collected downhole dynamic event data using a computing system located downhole to convert the time-domain data into frequency-domain data, and extracting digital filter coefficients from the frequency-domain data.

Abstract: Methods, systems, and media for providing sound level information for a particular location are provided. In some embodiments, the method comprises: receiving, from a user device, a request for sound level indications associated with a geographic region; in response to receiving the request, identifying a plurality of locations associated with the geographic region; identifying, for each location in the plurality of locations, at least one sound level reading corresponding to the location; generating, for each location in the plurality of locations, sound level indications based on the at least one sound level reading corresponding to the location; and transmitting at least one of the sound level indications and an identifier of at least one location in the plurality of locations corresponding to the at least one of the sound level indications to the user device.

Abstract: According to an embodiment, a detection system includes a plurality of first sensors, a second sensor, a first calculator, and a second calculator. Each of the first sensors is configured to detect an elastic wave generated from a structure, and convert the elastic wave into a detection signal. The second sensor is configured to detect a noise propagating from surroundings, and convert the noise into a reference signal. The first calculator is configured to calculate a plurality of difference detection signals based on the respective detection signals and the reference signal. The second calculator is configured to calculate a position of a generation source of the elastic wave from the plurality of difference detection signals.

Abstract: An elevator system (100) includes an elevator drive system (101) including a tension member (103) supporting an elevator car (106) under tension and a monitoring system (102). The monitoring system includes a vibration sensor (111) for detecting vibration of at least one of the tension member and the elevator car and an analysis unit (112) for determining a level of wear and life of the tension member based on the vibration of the tension member detected by the vibration sensor.

Abstract: Methods or systems for identifying seismic or acoustic signals of interest originating with moving motorized vehicles or footstep movement or stationary or moving machinery. A related system for monitoring an area includes a plurality of sensing devices each comprising a frame and a piezo-electric sensor element. A monitoring device is coupled to receive information from each of the sensing devices. One method includes providing a processing chain coupled to receive signal data from a sensor device which receives the signals, including a detection stage, a Joint Time Frequency (JTF) domain stage, and a classification stage. The detection stage identifies presence of signals that emerge from the background. The JTF domain stage estimates the state of the signals of interest over time. The classification stage assesses the previously derived information to form a decision about source identity. In one embodiment, the detector stage performs detections on a single cycle basis.

Abstract: According to an embodiment, a structure evaluation system includes a plurality of sensors, a position locator, a velocity calculator, and an evaluator. The sensors detect an elastic wave generated from a structure. The position locator derives a wave source distribution of the elastic waves generated from the structure, on the basis of the elastic waves. The velocity calculator derives a propagation velocity of the elastic wave generated from the structure, on the basis of the elastic waves. The evaluator evaluates the soundness of the structure on the basis of the wave source distribution and the propagation velocity of the elastic waves.

Abstract: Embodiments of the present invention provide a system and method for accurate, field-ready, non-destructive, and three-dimensional plant root characterization using acoustic signals. The system is portable, fast, precise, and can be used in field conditions, including moist soil, to visualize root structure or mass distribution, without damaging growing crops. The system may also be applied to characterize other underground objects, such as pipes, building foundations, archaeological artifacts, or mineral ores. During operation, the system generates a source acoustic signal. The system sends the source acoustic signal to an actuator acoustically coupled directly to a plant. The system obtains a response acoustic signal from an underground transducer monitoring a root of the plant. The system analyzes the response acoustic signal according to a model and based on the source acoustic signal. The system then determines, based on the analyzed response acoustic signal, a physical configuration of the plant root.

Abstract: Methods and systems for determining crack propagation length using a technique based on acoustic signature are disclosed. An acoustic signature is measured and recorded at a first location via acoustic wave generated by structural vibrations caused by a harmonic loading with predefined magnitude acted at a second location on the structure. Structure contains an unknown length of crack propagation inside. Unknown length is determined by comparing the measured and recorded acoustic signature with numerically-computed acoustic signatures stored in a database, which contains at least one relationship of the numerically-computed acoustic signatures versus respective crack propagation lengths at various stages of numerically-simulated crack propagation trajectory.

Abstract: A system for quality monitoring of additive manufacturing includes an acoustic emission (AE) sensor configured to be attached to an additive manufacturing substrate and to output a sensor signal indicative of acoustic vibrations received at the AE sensor and an AE module. The AE module is configured to receive the sensor signal from the AE sensor and process the sensor signal to determine at least one characteristic of an additive manufacturing process and/or an additively manufactured article.

Abstract: An optical scanner includes: a movable part including a light reflection portion that reflects light; a first shaft part that swingably supports the movable part about a first axis; a support part that supports the first shaft part; a recessed portion provided in the support part, and having an opening portion in one surface of the support part and having a side surface opening portion in a side surface of the support part connected to the one surface of the support part; and a regulating member provided in the recessed portion and partially projecting from the side surface opening portion with the projecting portion located between the support part and the movable part.

Abstract: Embodiments of a sample testing system of the present invention generally include two internally threaded caps; an externally threaded outer tube having a tapered internal bore and external circumferential grooves proximate each end thereof; an O-ring seated in each groove; and a plurality of inner tube sections cooperatively arranged to form an externally tapered inner tube structure that is disposed within the outer tube; wherein each cap is sealingly attached to an end of the outer tube via threading engagement therewith. Various embodiments utilize at least one closed-ended cap and/or at least one cap having a port extending through an end thereof, which may also incorporate a piston cavity and a piston having two circumferentially disposed O-rings. Embodiments allow for inner tube structure removal and separation of the inner tube sections for cured sample recovery. Embodiments of a method of using the system to cure a sample are also provided.

Abstract: A method of sorting chips divided from a plate-shaped workpiece into acceptable chips and defective chips includes an ultrasonic vibration applying step of applying ultrasonic vibrations to chips, a fracture confirming step of confirming whether the chips have been fractured in the ultrasonic vibration applying step or not, and a sorting step of sorting those chips which have been confirmed as not fractured in the fracture confirming step as acceptable chips. The ultrasonic vibrations applied to the chips in the ultrasonic vibration applying step are set to values that do not cause chips to be fractured if the chips are free of minute fractures and cause chips to be fractured if the chips contain minute fractures.

Abstract: A method for generating fluid flow images of a region of interest is disclosed. The method includes: scanning the region of interest to acquire a set of 4D-Flow magnetic resonance images, wherein the set comprises an anatomical magnitude image, a first velocity component image, a second velocity component image, and a third velocity component image; isolating the anatomical magnitude image, the first velocity component image, the second velocity component image, and the third velocity component image from the set of 4D-Flow magnetic resonance images; converting the first, second, and third velocity component images into a velocity vector field; modeling a location of an anatomical wall within the region of interest; calculating at least one flow dynamics parameter for the region of interest; and generating a visual representation of the anatomical wall and the at least one flow dynamics parameter.

Abstract: An apparatus for detecting and recording accelerations experienced by a structure and a method for operating the apparatus are provided. The apparatus includes an accelerometer, processor, and non-volatile computer memory device. The method includes operating the apparatus in a reduced power state, detecting an acceleration having a magnitude that is greater than a first preselected threshold magnitude, switching each of the accelerometer, processor, and non-volatile computer memory device to a fully operational state, storing accelerometer data in a buffer, switching the processor and computer memory device to a reduced power state until the accelerometer signals that further data is available, storing any further accelerometer data in the buffer, and repeating the steps until a predetermined time has elapsed since the accelerometer last detected an acceleration having a magnitude which is greater than a second preselected threshold magnitude.

Abstract: A device for detecting a structure-borne sound signal, in particular for detecting a structure-borne sound signal caused by an event of damage on a component to be monitored, having at least one structure-borne sound sensor, at least one signal-conducting connection of the structure-borne sound sensor to an evaluation device, and a protective body. The structure-borne sound sensor has a structure-borne sound-conducting connection to the protective body and the protective body has a structure-borne sound-conducting connection to the component to be monitored.

Abstract: This disclosure provides systems and methods for using a health monitoring system with acoustic emissions (AE) signals and the resonance frequency of the damage state of a component in a machine to monitor component health. AE signals collected from sensors on an operating machine are analyzed to identify signal features or events that correspond to component resonance frequencies. The AE signal features proximate to the component resonance frequencies and how those features and the component resonance frequency changes over time enable the identification and monitoring of damage states, such as cracks in the stator vanes of a compressor, gas turbine, steam turbine, or generator.

Abstract: A method for forming a structural-strain sensor network on a structure is provided. The sensor network has plural nanocomposite sensing elements having high sensitivity, and can be quickly fabricated. The method comprises attaching a molding layer having openings onto the surface, and filling the openings with a coating material made of nanocomposite hybrid material. After immobilizing the coating material in the openings, the sensing elements are formed and the molding layer is removed. Electrical wires are formed on the surface such that two opposite electrodes are formed on each sensing element. The resistance between the two electrodes indicates a strain experienced. The sensor network finds applications in identifying a damaged location or an impact location on the structure for structural health monitoring. Voltage waveforms measured at the sensing elements are analyzed to estimate the damaged location or the impact location according to a guided-wave propagation model.

Abstract: A device and method for determining characteristics of a concrete sample includes the use of multiple transducers at pre-determined positions with respect to each other. The transducers are coupled to the concrete surface so that they can impart and/or receive mechanical waves from the sample. Mechanical waves may be imparted to the sample by one or more transducers or by an impact hammer. A control device receives the output from receiving transducers and analyzes data there from to determine a desired characteristic of the sample.

Abstract: Various systems and method for acoustic monitoring of smelting furnaces and similar devices are disclosed. Acoustic sensors (and optionally other sensors) are mounted to the furnace. Acoustic emission events generated in the furnace are analyzed to identify conditions that exceed one or more thresholds. The location of acoustic emissions may be identified and reported. Output signals may be generated in response to acoustic emissions. The location of acoustic emissions may be used to identify the location of potential failures in the furnace.

Abstract: Delay line memory device, systems and methods are disclosed. In one aspect, a delay line memory device includes a substrate; an electronic unit disposed on the substrate and operable to receive, amplify, and/or synchronize data signals into a bit stream to be transmitted as acoustic pulses carrying data stored in the delay line memory device; a first and a second piezoelectric transducer disposed on the substrate and in communication with the electronic unit, in which the first piezoelectric transducer is operable to transmit the data signals to the acoustic pulses that carry the data through the bulk of the substrate, and the second piezoelectric transducer is operable to transduce the received acoustic pulses to intermediate electrical signals containing the data, which are transferred to the electronic unit via an electrical interconnect to cause refresh of the data in the delay line memory device.

Abstract: The present disclosure is directed to a printing device, a system, and a method. The printing device according to one embodiment includes a chassis substantially housing a sheet feeder, a sheet conveyor, and a print applicator; a microphone externally mounted to the chassis for converting audio signals sensed by the microphone external to the printing device to a raw analog electrical signal; an analog low-pass filter for filtering out high frequency harmonics from the raw analog electrical signal to result in a filtered electrical signal; a controller comprising an analog-to-digital port, a processor, and a memory. The controller receives the filtered electrical signal at the analog-to-digital port and samples the filtered electrical signal at a sample rate of at least twice a bandwidth of the filtered analog electrical signal to result in a sampled signal clip. The controller determines a time duration of a portion of the sampled signal clip associated with a print cycle event.

Abstract: An ultrasonic testing device includes: a liquid tank that stores the liquid into which the differential casing is to be immersed; a workpiece holder that holds the differential casing and immerses the differential casing into the liquid in the liquid tank; an ultrasonic probe that conducts an ultrasonic testing of the welded part of the differential casing by irradiating the ultrasonic wave to the welded part and receiving a reflected wave; an image processing module that generates an ultrasonic image based on the reflected wave received by the ultrasonic probe; and a replacer that replaces gas inside an air gap formed at a weld toe of the welded part with test liquid. The replacer replaces the gas inside the air gap by the test liquid before the ultrasonic probe irradiates the ultrasonic wave.

Abstract: An ultrasonic HIFU transducer (120) has a threaded opening into which a modular cavitation sensor (90) is removably located. The modular cavitation sensor includes a modular housing (92) containing a piezoelectric transducer for sensing acoustic signals indicative of cavitation. The modular cavitation sensor has electrodes (96,98) which engage spring contacts (112,114) in the threaded opening when the modular housing is screwed into the threaded opening. A damaged sensor can be unscrewed and replaced simply without connectors or soldering.

Abstract: Systems and methods for generating a three-dimensional image of a proppant-filled hydraulically-induced fracture in a geologic formation are provided. The image may be generated by capturing electromagnetic fields generated or scattered by the proppant-filled fracture, removing dispersion and/or an attenuation effects from the captured electromagnetic fields, and generating the image based on the dispersion and/or attenuation corrected fields. Removing the dispersion and/or attenuation effects may include back propagating the captured electromagnetic fields in the time domain to a source location. The image may be generated based on locations at which the back propagated fields constructively interfere or may be generated based on a model of the fracture defined using the back propagated fields.

Abstract: The present application relates to an apparatus for detecting software interference and the method of operating thereof. A processor and at least one shared resource form a computing shell to execute a first, functional safety critical application and at least one second application in time-shared operation. One or more performance counters are provided to adjust a counter value in response to a performance related event. A reference value storage stores one or more threshold values, each of which is associated with one of the performance counters. A comparator receives the performance counter values, compares the performance counter values with the respective threshold values and generates at least one comparison signal in response to results of the comparisons. An interference indication generator receives the at least one comparison signal and generates at least one interference indication in response to the at least one received comparison signal.

Abstract: A signal processing apparatus includes a filter that performs filtering of a correction filter characteristic including a reverse characteristic of an output characteristic of a microphone on a signal acquired by the microphone.

Abstract: A method for measuring noise of a magnetic head includes setting a plurality of threshold values, applying bias current or voltage to a read element of the magnetic head, applying an external transverse magnetic field to the magnetic head, amplifying output signal from the read element to produce an amplified signal, filtering the amplified signal to produce a filtered signal, generating an enable signal for each threshold value in a predetermined time window by a counting control means with input signals which include the filtered signal and the threshold value, measuring the cumulative time duration of each enable signal, making an amplitude-duration distribution according to the cumulative time durations and the threshold values, calculating a plurality of parameters according to the amplitude-duration distribution and analyzing the parameters with a plurality of predetermined criteria to determine the defects of the magnetic head.

Abstract: A method of determining a state of biofouling of a membrane is provided. The membrane is contained within a flow cell and the flow cell has an outer surface coupled to a tranducer, The method comprises introducing inorganic particles into the flow cell such that the inorganic particles form a part of a top surface of a foulant layer on the membrane. The transducer then emits acoustic waves towards the membrane and an acoustic signature of reflected sound waves are detected. A state of biofouling of the membrane is determined based on the detected acoustic signature. A method and an apparatus are also provided for determining a state of biofouling in commercial membrane modules such as spiral wounded membrane modules.

Abstract: A test and measurement apparatus, system, and method for synchronizing an acquisition or triggering system to a specific burst of interest. The subject apparatus and method triggers on varying energy content of a signal qualified by time in the presence of high-frequency input signal bursts, by using an adjustable pulse width envelope detector, disposed in the signal path of the trigger circuitry, as a digital rectifier or to otherwise process and extract an envelope signal. An RF envelope probe having an analog envelope detector among other suitable components is disclosed. A method is implemented for isolating an interval of interest in a signal under test. An envelope detector circuit produces an envelope signal from the signal. Trigger circuitry receives the envelope signal from the envelope detector, and isolates the interval of interesting in the signal under test using the envelope signal.

Abstract: A device and a method for monitoring the operational state of rotor blades of a turbine from a position facing the blade tip of a passing rotor blade: A wavesource generates an electromagnetic wave and a wave guide directs the wave towards the blade tip. The waveguide is included in a resonator defining at least one discrete resonance frequency of the wave on the waveguide. An aperture at its front end emits an energy fraction of the wave toward the blade tip. The frequency of the wave is adjusted to the resonance frequency of the resonator at the momentary operation conditions, and a measuring unit compares at least one measurement parameter of the wave directed towards the blade tip with the corresponding measurement parameter of the wave reflected from the blade tip.

Abstract: According to the present invention, it is possible to determine a defect on a product caused in a press process by applying a predetermined acoustic signal to an object to be inspected and then sensing propagation of the applied signal, and it is possible to improve inspection performance, using an acoustic sensor capable of sensing sounds in an audible band and a high-frequency sensor capable of sensing sounds in an non-audible band.

Abstract: Provided are a device (10) and a method for measuring the crispness of a food product. An item to be measured (22) comprising a porous food product is broken apart by causing the blade of a knife (14) to penetrate into the item. A vibration detector (18) attached to the knife (14) detects crack vibrations from cracks that form when the item to be measured (22) is broken apart. In a computer (20), the small crack vibrations of a predetermined vibration power or less that are included in the crack vibrations within an individual cracking duration time are extracted from the detected crack vibrations. Crispness is measured on the basis of the number of extracted small crack vibrations counted (number of cracks).