Abstract: A method for detecting an anomaly and measuring its size may include generating a wave signal into a structure being evaluated and collecting at least one of any front and back scattered wave data and any side scattered wave data caused by the wave signal impacting an anomaly. The method may also include processing the at least one front and back scattered wave data and side scattered wave data to measure a size, location, and shape of the anomaly.

Abstract: An ultrasonic interferometer for the characterization of the matter (solids, fluids & gases) in a medium is described, along with a method of using the same. The interferometer accurately determines the travel time of the multi-frequency ultrasonic signal in the matter that is being queried. By carefully selecting the design of the multi-frequency ultrasound signal, various properties of the material can be derived using a trainable classification system to classify or recognise the substance, or state of a process. The apparatus exploits the normally undesirable higher harmonics characteristics of the piezoceramic transducer to gain penetration through a spatial-frequency window that is not suitable for the higher frequency signals that are required to achieve the measurements.

Abstract: The average strength or Young's modulus of the constituent particles of a sample is determined from the measured speed of sound propagated from a source through the sample to a receiver. Other sample data, such as the porosity, Poisson's ratio and the pressure applied to the sample, are also used in the determination. However, no data pertaining to individual particle sizes is required. The method provides a non-destructive test for the average strengths of materials such as iron ore pellets, alumina powder, silica flour, and coal dust.

Abstract: The invention relates to a method of generating a predetermined objective wave field in a medium using a first network of transducers T1-Tn). The inventive method consists in first using each transducer i of the first network to emit an approximation of the signal ei(t). Subsequently, each transducer of a second network of transducers (T?1-T?m) is used to emit an error signal corresponding to the time reversal of the difference between the signals captured from said first emission and objective signals. Finally, approximation ei(t) is corrected by subtracting the time reversal of the signal captured by each transducer i using the error signal.

Abstract: A diagnosis device for diagnosing loosening of a stator core of a rotary electrical machine. The diagnosis device has: excitation means for vibrating the stator core in the radial direction; vibration detection means for detecting the vibration of the stator core in the radial direction; means for frequency-analyzing an output signal of the vibration detection means that detects vibration generated in the stator core when the stator core is vibrated by the excitation means so as to extract a measurement natural vibration mode of the stator core in a circular ring natural vibration mode; means for estimating a circular ring natural vibration mode of the stator core from shape data of the stator core; and means for determining a clamping state of the stator core by comparing the measurement natural vibration mode and a determination criterion obtained based on the estimated natural vibration mode.

Abstract: Device and method for detecting a defect in a workpiece with a broadband transducer (10), a driving circuit connected to the transducer to operate the transducer in a actuator mode, a signal output circuit connectable to operate in a sensor mode, a control for selectively connecting the transducer to the driving circuit or signal output circuit wherein the driving circuit includes at least a pair of oscillators for generating signals of at least frequencies F1 and F2 and a summer for summing the signals to provide a driving circuit for the transducer.

Abstract: A free-hand inspection apparatus for non-destructively inspecting a structure includes an array and an inertial sensor. The array includes a plurality of elements for transmitting and receiving inspection signals towards and from a structure being inspected. The inertial sensor measures acceleration and angular rotation rate in X, Y, and Z directions of the array.

Abstract: The present invention is an apparatus and method for determining the remaining service life of electrochemical energy generation and storage device including batteries, supercapacitors, DSSC solar cells and fuel cell. Measurements are performed by passing ultrasonic oscillations through the test object. The apparatus of the present invention comprises two arrays of transmitting and receiving ultrasonic probes between which the object being tested is affixed. Polyurethane tips are used for matching the acoustic resistance of the probes with the test object body. The apparatus positions the transmitting and the receiving probe arrays relative to each other. The calibration characteristic for determining the remaining service life of a the test object are established from the signal values from the ultrasonic probes related to the number of charge-discharge cycles obtained at various charge values.

Abstract: An in-line inspection tool is disclosed for inspecting the wall of a pipeline while traveling therethrough. The in-line inspection tool may include a transmitter, a signal generator, one or more receivers, and a decoder. The signal generator may generate a pseudorandom signal, generate an inspection signal, and drive the transmitter with a convolution of the pseudorandom signal and the inspection signal. The transmitter may transmit the convoluted signal to the wall of the pipeline. One or more receivers may receive from the wall of the pipeline a received signal comprising at least one of the convoluted signal and a reflection of the convoluted signal. The decoder may identify the inspection signal within the received signal by cross correlating the received signal and the pseudorandom signal.

Abstract: An ultrasonic inspection system utilizes a tunable digital filter with 4× interpolation. The system is used for scanning objects to be tested and includes a transmit/receive device to generate a test signal and receive an echo signal. A signal processing circuit processes the echo signal with one or more digital to analog converters for converting an analog version of the echo signal to a digital echo signal in the form of streaming digital data which is stored in a memory. The data is stored at a first data rate and read out at the second, slower data rate. An averaging decimator receives and processes the data from the memory and supplies it to an IIR filter and subsequently to an FIR filter and ultimately to a box car filter to effect processing thereon which increases the perceived resolution of the data by a given factor, preferably by a factor of 4.

Abstract: The present invention relates to a method for examining a medium (19), comprising the following steps of: transmitting a measurement input signal (4) comprising at least one measurement frequency, wherein the measurement input signal (4) is coupled into a medium (19); receiving a measurement output signal (9) emerging from the medium (9); transmitting a counter measurement input signal (13) comprising at least one counter measurement frequency, wherein the counter measurement frequency essentially corresponds to the measurement frequency, and wherein the counter measurement input signal (13) is coupled into the medium (19) simultaneously and in an opposite direction to the measurement input signal (4); receiving a counter measurement output signal (16) emerging from the medium (19); calculating a Doppler correction by comparing the counter measurement input signal (13) with the counter measurement output signal (16) in terms of the counter measurement frequency and by comparing the measurement input signal

Abstract: The present invention relates to a vibration monitoring device and methods for using the same. Specifically, the invention relates to a vibration monitoring device which may be utilized throughout a delayed coker unit operation to ascertain whether the cutting tool is boring, cutting or ramping mode.

Abstract: A description is given of a method of spectral analysis of a radio frequency ultrasonic signal reflected by a structure subjected to echographic examination, comprising the steps of: a) transmitting an ultrasonic excitation signal into a portion of said structure under examination; b) receiving a radio frequency response signal from said structure; c) applying a time-frequency transform to said radio frequency response signal, dividing the radio frequency response signal into a plurality of frequency bands; d) calculating a local spectral parameter from the values of the time-frequency transform.

Abstract: An ultrasonic measurement method and an ultrasonic measurement apparatus are capable of performing an inspection for a short time with a high SN ratio and a small variation (that depends on an inspection direction) in sensitivity in a process for detecting a defect in all directions at 360 degrees using a matrix array sensor without performing mechanical scanning in all directions, while reducing noise that is caused by a bottom surface echo. An element selecting circuit selects a group of a plurality of ultrasonic transducer elements for transmission from among ultrasonic transducer elements that constitute a two-dimensional array sensor so that the ultrasonic transducer elements for selected for transmission are arranged in line symmetry with respect to a first line symmetric axis to set the group selected for transmission.

Abstract: The invention is directed toward a new method for estimating and imaging the spatial and temporal mechanical behavior of materials in responses to a mechanical stimulus. This method is designed to work in inherently noisy applications, such as the imaging of the time-dependent mechanical behavior of biological tissues in vivo and using a preferred hand-held configuration of scanning.

Abstract: A method for determining a location of incipient damage of an object comprises insonifying the object at a plurality of locations using ultrasonic signals during an inspection, acquiring signals indicative of a possible damage condition from the plurality of locations of the insonified object in said inspection, determining a value for each of the locations to indicate accumulated damage by mathematically combining the acquired signals from said inspection and at least a portion of prior inspections, and comparing the values of the plurality of locations to determine a location indicating possible incipient damage.

Abstract: A probe is inserted at a predetermined speed into a food to be measured, and vibrations created by the insertion are acquired by a piezoelectric element. The vibrations are displayed, and the pulse number per unit time on the basis of the insertion speed of the probe is calculated so that the oral sensation of the food is quantitatively specified with the pulse number.

Abstract: A stirring apparatus includes an acoustic wave generating unit that is provided in a vessel keeping a liquid and generates an acoustic wave toward the liquid, the liquid being stirred by the acoustic wave; a driving unit that drives the acoustic wave generating unit; a detecting unit that detects a reflected power reflected from the acoustic wave generating unit; and a determining unit that determines a presence of an abnormality based on the reflected power detected by the detecting unit. The determining unit determines the presence of the abnormality when a difference between an in-operation reflected power which is reflected from, during an operation, the acoustic wave generating unit and a reference reflected power of the acoustic wave generating unit at a same driving frequency exceeds a predetermined value.

Abstract: A system and method for non-destructively determining the grain orientation of a crystalline material using x-ray diffraction techniques to non-destructively analyze material and, more particularly, to a system and method for determining the grain orientation of an underlying crystalline material covered by an overlying polycrystalline material. Further, the system and method relate to the use of x-ray diffraction to non-destructively characterize parts and components to determine whether to accept or reject those components or parts for use in application.

Abstract: A laser-based ultrasonic technique for the inspection of thin plates and membranes employs an amplitude-modulated laser source to excite narrow bandwidth Lamb waves. The dominant feature in the acoustic spectrum is a sharp resonance peak that occurs at the minimum frequency of the first-order symmetric Lamb mode, where the group velocity of the Lamb wave goes to zero while the phase velocity remains finite. Experimental results with the laser source and receiver on epicenter demonstrate that the zero group velocity resonance generated with a low power modulated excitation source can be detected using an optical probe such as a Michelson interferometer coupled to a lock-in amplifier. This resonance peak is sensitive to the thickness and mechanical properties of plates and may be suitable, for example, for the measurement and mapping of nanoscale thickness variations.

Abstract: In a comparison between master data created from a waveform signal of an observed object of an acceptable article and a waveform signal obtained from a non-measured observed object, time phase difference generated in the observed object is corrected, and difference with the master data is detected. As a first stage, quality determination is performed on the non-measured observed object with a long interval master data using the created master data, and the time phase difference is corrected. Then, as a second stage, quality determination is performed with the short interval master data divided on a time axis and the similarly divided waveform signal of the observed object. The time phase difference generated between the observed objects (acceptable article and defective article) is thereby corrected, and quality determination of high accuracy can be performed from the comparison with the waveform signal of the acceptable article.

Abstract: A system and method are disclosed that facilitate generating visual representations of characterized tissue based upon ultrasound echo information obtained from a portion of an imaged body. The system includes a first filter having a first filter band that is applied to a near range portion of the ultrasound echo information to render near range filtered echo information. A second filter, having a second filter band that covers a frequency range of the first filter band, is applied to a far range portion of the ultrasound echo information to render far range filtered echo information. The system furthermore includes a set of characterization criteria that are applied to the near and far range filtered echo information. The characterized near and far range image data are thereafter combined into a single tissue-characterization image.

Abstract: An ultrasonic inspection apparatus includes: an ultrasonic probe apparatus including an ultrasonic transducer; a drive element selecting section that selects a required piezoelectric vibrator of the ultrasonic transducer; a signal detecting circuit that detects an electric signal dependent on a reflected echo of an ultrasonic wave emitted from the selected piezoelectric vibrator; a signal processing section that produces data on an internal image of the inspection object based on the detected reflected echo; a second display unit that combines multiple pieces of image data acquired from the signal processing section and displays an integrated visualization data result; and an second input unit that is used to perform an operation command such as a command input to start or terminate an inspection or an a command to set inspection condition.

Abstract: The invention is directed toward a new method for estimating and imaging the spatial and temporal mechanical behavior of materials in responses to a mechanical stimulus. This method is designed to work in inherently noisy applications, such as the imaging of the time-dependent mechanical behavior of biological tissues in vivo and using a preferred hand-held configuration of scanning.

Abstract: A method for nondestructive testing of the pipes for detecting surface flaws is disclosed. With of the method, flaws can be detected and analyzed in near-real-time while the pipe is produced. The data obtained by ultrasound sensors are digitized in a time window following a trigger pulse, and the digitized data are processed in a digital processor, for example a DSP, using wavelet transforms. The evaluated quantity is compared with a reference value, wherein a determined flaw-based signal can be uniquely associated with the flaw located on the pipe surface.

Abstract: Presented is a method of operating a capacitive microfabricated ultrasonic transducer (cMUT) array with multiple firings of varying bias voltage polarity patterns to improve its performance in imaging non-linear media, such as in contrast agent imaging or tissue harmonic imaging. Additionally, transducers incorporating the method are provided. The method of cMUT operation and the corresponding cMUT does not require pre-distortion or phase inversion of the transmit signal and can achieve an improvement in the elevation focus of the cMUT, as compared to the elevation focus that a single firing can achieve. Further, the method of operating the cMUT minimizes the deleterious effects that result from insulators being subjected to high electric fields.

Abstract: A transducer assembly is provided including a transducer array comprising a plurality ‘M’ of transducer elements and a sub-aperture processor comprising a plurality ‘P’ of input channels and an output channel. The plurality ‘P’ of input channels is coupled to the ‘M’ transducer elements and a plurality ‘R’ of switching elements in operative association with the output channel of the sub-aperture processor to switchably couple the output channel to at least one of a plurality of ‘N’ system channels.

Abstract: A method of analyzing ultrasonic inspection data from turbine wheel or bucket dovetail fingers for a crack about a ledge thereof with the turbine wheel or bucket having a number of adjacent holes therethrough. The method may include inserting an ultrasonic probe into a first hole, rotating an ultrasonic beam of the ultrasonic probe to scan the adjacent holes, scanning each adjacent hole, and determining the presence of the crack in the ledge by the failure to receive a signal from one or more of the adjacent holes.

Abstract: Disclosed are systems and methods that permit both real-time, and off-line, measurement of weld penetration depth. Exemplary systems and methods comprise an ultrasound source, such as a pulsed Nd:Yag laser, that simultaneously generates longitudinal and shear waves that radiate adjacent one side of a weld joining two specimens. An ultrasonic sensor, such as an electro-magnetic acoustic transducer or a piezo-electric transducer, capable of detecting shear and/or longitudinal waves, is disposed on an opposite side of the weld from the source. A signal processor is coupled to the sensor that processes time of flight signals for selected longitudinal or shear waves transmitted across the weld seam. The signal processor implements an algorithm that computes the weld penetration depth from the time of flight signals.

Abstract: An ultrasonic inspection system utilizes a tunable digital filter with 4× interpolation. The system is used for scanning objects to be tested and includes a transmit/receive device to generate a test signal and receive an echo signal. A signal processing circuit processes the echo signal with one or more analog to digital converters for converting an analog version of the echo signal to a digital echo signal in the form of streaming digital data which is stored in a memory. The data is stored at a first data rate and read out at the second, slower data rate. An averaging decimator receives and processes the data from the memory and supplies it to an IIR filter and subsequently to an FIR filter and ultimately to a box car filter to effect processing thereon which increases the perceived resolution of the data by a given factor, preferably by a factor of 4.

Abstract: A method is provided for analyzing vibrations of a variable speed rotating body. The method includes producing a signal that is proportional to an acceleration of the rotating body and producing a plurality of pulses. Each pulse represents a revolution of the rotating body and is indicative of a vibration sample at a rotational position of the rotating body. The signal is converted to a numeric value that is indicative of a vibrational amplitude of the rotating body. The plurality of pulses are converted to revolution time periods indicative of a rotational rate of the rotating body. The method also includes producing a harmonic vibrational amplitude at a harmonic of the rotational rate of the rotating body, and representing a phase of the harmonic vibrational amplitude relative to the rotational position of the rotating body.

Abstract: A method and a device for detecting discontinuities in a material region having at least one probe which has a plurality of ultrasonic transducer elements and having an evaluation and control device are proposed, in which the transducer elements are disposed diagonally at an angle to the surface of the material region and are actuated via delay elements in such a manner that a defocusing sound field is beamed in. The received signals of the transducer elements are supplied to a plurality of evaluation modules for parallel and simultaneous further processing for different angle values or angle ranges, the number of evaluation modules corresponding to the different angle values or ranges.

Abstract: The invention relates to a method and a device for identifying a damaged bearing (4a, 4b) of a rotating shaft (1). According to the invention: the rotational speed (n) of the shaft (1) is determined; the alternating component (nAC) of the rotational speed (n) is determined, together with a smooth curve (h) of said alternating component (nAC) of the rotational speed (n); the smooth curve (h) is converted into the frequency range and a frequency response (B) of the value of the smooth curve (h) is determined. Said frequency response (B) of the value of the curve is monitored for the passing of a threshold value (G1, G2, G3, G4) and if said threshold value (G1, G2, G3, G4) is exceeded, a damaged bearing (4a, 4b) is identified. The invention thus provides a method and a device for identifying a damaged bearing (4a, 4b) of a rotating shaft (1) of a motor, which do not require a vibration sensor (11) to identify a damaged bearing (4a, 4b) of said shaft (1).

Abstract: Embodiments of techniques to verify the interference fit of fasteners are disclosed. In one embodiment, a method includes aligning a probe proximate a fastener, the fastener being disposed within a material. A dynamic stress signal is generated from the probe using a low frequency transducer, and the dynamic stress signal is interrogated after it passes between the fastener and the material. An interference fit is then determined based on the interrogated dynamic stress signal.

Abstract: An ultrasonic interferometer for the characterization of the matter (solids, fluids & gases) in a medium is described, along with a method of using the same. The interferometer accurately determines the travel time of the multi-frequency ultrasonic signal in the matter that is being queried. By carefully selecting the design of the multi-frequency ultrasound signal, various properties of the material can be derived using a trainable classification system to classify or recognise the substance, or state of a process. The apparatus exploits the normally undesirable higher harmonics characteristics of the piezoceramic transducer to gain penetration through a spatial-frequency window that is not suitable for the higher frequency signals that are required to achieve the measurements.

Abstract: A speaker unit has a plurality of sound sources each outputting a sound wave. The compressional, sound wave output from the speaker unit arrives, or vibrates air, which moves a movable part of a three-axis acceleration sensor, or a microstructure of a chip to be tested TP. As the movable part thus moves, a value in resistance accordingly varies, and such variation is measured as based on an output voltage provided via a probe. A control unit determines a property of the three-axis acceleration sensor from a value in property as measured or measurement data. Furthermore, the plurality of sound sources can be spaced by a pitch of a predetermined value set as based on their difference in the distance to the movable part of the three-axis acceleration sensor and the wavelength of the test wave to apply a composite test wave to the movable part such that the composite sound wave's composite sound field is maximized.

Abstract: An ultrasound inspection system is provided for inspecting an object. The inspection system includes an ultrasound probe configured to scan the object and acquire a plurality of ultrasound scan data. The inspection system further includes a processor coupled to the ultrasound probe and configured to apply a transfer function to the ultrasound scan data to compensate for distortion of a plurality of ultrasound signals through the object and thereby generate a plurality of compensated ultrasound scan data, and to process the compensated ultrasonic scan data to characterize a feature in the object.

Abstract: Apparatus for use in controlling snoring, including: a sensor system for sensing snoring by a person while sleeping, and a stimulus device effective, when actuated by the sensor system, to apply a stimulus to the person for producing a response tending to interrupt the person's snoring. The stimulus device includes a vibrator and a band for enclosing a body part of the person and for applying a vibration to the body part. Also described is a force or displacement sensor, which includes a housing filled with a liquid having high transmissivity and low attenuation properties with respect to acoustical waves, and an acoustical transmitter and an acoustical receiver carried by opposed walls of the housing spaced from each other to define between them an acoustical transmission channel of the liquid. The housing is deformable by a force such as to change the length of the acoustical transmission channel in accordance with the applied force.

Abstract: A method and an array-based system for inspecting a structure are provided that can identify unacceptable levels of porosity, microcracking or defects attributable to thermal damage. The inspection system includes a two-dimensional array of ultrasonic transducers, and an array controller configured to trigger at least one ultrasonic transducer to emit an ultrasonic signal into the structure. The array controller is also configured to receive data representative of backscattered signals preferentially received by at least one ultrasonic transducer from a portion of the structure offset from the at least one ultrasonic transducer that was triggered to emit the ultrasonic signal.

Abstract: An ultrasonic sensor for detecting an object includes: a substrate; a transmission device for transmitting an ultrasonic wave; a plurality of reception devices for receiving the ultrasonic wave; and a circuit for processing received ultrasonic waves, which are received by the reception devices after the ultrasonic wave transmitted from the transmission device is reflected by the object. The transmission device and the reception devices are integrated into the substrate. The dimensions of the sensor are minimized, and detection accuracy of the sensor is improved.

Abstract: The invention relates to a method for evaluating pressure containers made of a composite material by acoustic emission testing. The method comprises the steps: (a) determining a sufficient number of internal pressure-dependent acoustic emission characteristics (AE characteristics) of pressure containers from identical production that have been classified as being without defects in predetermined phases of a time-controlled pressure acting upon the pressure container (AE test procedure) with one or more acoustic emission channels (AE channels) using acoustic emission sensors (AE sensors) of a predetermined position (one AE characteristic per AE sensor or AE channel.

Abstract: A method of detecting an internal flaw in a particulate filter includes a step of coupling ultrasonic transducer with the particulate filter. The method also includes a step of moving at least one of the ultrasonic transducer and the particulate filter relative to the other. Consistent coupling of the ultrasonic transducer with the particulate filter is maintained during the moving step. Ultrasonic energy is transmitted from the ultrasonic transducer through a majority of a volume of the particulate filter. The method also includes a step of determining if the particulate filter includes an internal flaw using the ultrasonic energy.

Abstract: The invention relates to a method for representing echo signals that are obtained with the aid of an ultrasonic test apparatus used for non-destructively testing a test piece. Said ultrasonic test apparatus comprises a probe, especially an angled probe, a monitor with a display device for representing the received echo signals in an cross-sectional image such that at least one front face and a back wall of the test piece can be recognized. A flaw is detected from different arrangements of the angular probe, represented, and an error signal is determined. The test images are stored and then represented in a superimposed manner in an evaluation image such that the first and the second error signal can be recognized.

Abstract: This invention relates to the field of signal transit time sensors, in particular sensors based on ultrasonic transit times. Existing electronic control circuits for such transit time sensors for measurements on medical liquids, in particular blood, are extremely complex or their time resolution is limited. However, the present invention makes use of a simple measurement technique which cannot be used directly at first for the time resolution to be achieved. In this method, an ordinary sampling method is used to detect the received signal (12). An oscillator-like received signal (12) generated by an emitted step-like signal is first sampled during a half-period (14, 15) and is checked with the help of a selection criterion.

Abstract: A method for predicting the performance of tubular goods includes using a computer readable three-dimensional representation of tubular good which includes computer readable measurements of discrete segments of the wall of said tubular acquired by ultrasonic detection means, along with associated data representing the position of discrete segment and optionally ovality data to predict the effect of stress conditions, including tensile, bending, collapse, burst and aging forces upon said tubular and optionally analyzing sequential inspection of the same tubular good over a period of time predict when failure is likely to occur, and to avoid failure while maximizing the use of the tubular good.

Abstract: A spray coating apparatus comprises a spray gun (12) operable to deposit a sprayed coating via a spray nozzle (18) onto a surface, a mapping means (22) associated with the spray gun (12) operable to ascertain and store topographical characteristics of the surface, a position sensor (28) operable to ascertain the position of the spray gun (12) relative to the surface, a coating thickness monitor (26) operable to ascertain the thickness of a coating applied to the surface, and a nozzle control means (24) operable to control the deposition of the sprayed coating, wherein the nozzle control means (24), in use, control the deposition of the sprayed coating in response to information provided by the position sensor (28), the coating thickness monitor (26) and the mapping means (22).

Abstract: Method and systems for non-destructive testing of a gas or liquid filled object at atmospheric pressure or high pressure. The method includes steps of: providing an acoustic pulse reflectometry (APR) system having a wideband transmitter, a pressure sensor and a short mixed wave tube, performing at least one calibration to obtain at least one calibration parameter; attaching the object to the APR system and performing a measurement to obtain an object test result and processing the object test result and the at least one calibration parameter to obtain an object impulse response that reflects a status of the object.

Abstract: A system for sensing paper on a paper roll includes an ultrasonic transducer positioned to be in contact with an outer surface of the paper roll; a transmitter circuit in communication with the ultrasonic transducer, the transmitter circuit providing a transmit signal to the ultrasonic transducer, the ultrasonic transducer generating an ultrasonic signal in response to the transmit signal; a receiver circuit in communication with the ultrasonic transducer, the receiver circuit providing a received signal indicative of an ultrasonic return echo from the paper roll, the ultrasonic return echo resulting from the ultrasonic signal interacting with the paper roll; and a processor circuit, in communication with the transmitter circuit and the receiver circuit, that determines an amount of paper remaining on the paper roll in response to the transmit signal and the receive signal, the processor providing an output signal when the amount of paper remaining falls below a threshold.

Abstract: Some embodiments of the present invention provide systems, methods and apparatus for more accurately determining the thickness of a refractory lining included in an operating metallurgical furnace. Specifically, in some embodiments a transient propagated stress wave is used to determine the condition of a refractory lining, and additionally, provide a systematic way to include the affect that temperature has on the velocity of a compressive wave through a heated refractory material and/or accretions. As identified in aspects of the present invention, and contrary to the common understanding in the art, the velocity of a stress wave, at each frequency and in a refractory material, is not necessarily constant over a temperature range. In accordance with aspects of some specific embodiments of the invention, a scaling factor ? can be calculated for each refractory material to adjust for the presumed velocity of the stress wave through each refractory material.

Abstract: The method for obtaining an image of a part to be inspected includes the steps of determining, by simulation, the ultrasonic field (s0) generated by the propagation of a wave in a flawless reference part; transmitting an ultrasonic wave toward the part to be inspected; measuring the field (um) returned by the part to be inspected; subtracting from the field (um) returned by the part to be inspected an ultrasonic field (u0) obtained from a previous corresponding measurement on the reference part; calculating a variable related to the topological energy (ET) in the reference part on the basis of the field (s0) determined by simulation and of the field (um?u0) obtained by subtraction; and determining the image of the part to be inspected on the basis of the values for this variable.