Abstract: A method for testing or inspecting the integrity of package closure seals using contact and non-contact ultrasonic systems wherein a relative movement is created between a package seal and at least one ultrasonic transmitting transducer and at least one receiving transducer such that ultrasonic energy is focused so as to be transmitted toward and along a length of the seal from the transmitting transducer to the receiving transducer in a gaseous environment to thereby monitor energy signals which are analyzed to provide an indication of the seal integrity.

Abstract: A method of reducing sound-induced vibrations in pellicles used in lithographic production of microelectronic features comprises providing a pellicle for protecting a photomask, monitoring background sound in the vicinity, or vibration, of the pellicle, providing opposing sound waves to the background sound, and causing the opposing sound waves to strike the pellicle to substantially cancel vibrations due to the background sound or vibration. When the background sound strikes the pellicle on one surface of the pellicle, the opposing sound waves may strike the pellicle on the opposing surface of the pellicle, and may be provided with substantially the same frequency and amplitude in the same phase to the background sound. Alternatively, opposing sound waves may strike the pellicle on the same surface of the pellicle as the background sound waves, may be provided with substantially the same frequency and amplitude in opposing phase to the background sound.

Abstract: A data collector having an integrated laser tachometer. The data collector includes, within a housing that can be held by a single hand, circuitry for receiving a vibration signal to be digitized, as well as an optical system for receiving light from outside said housing to be converted to a digital tachometer signal. Digital signal processing circuits within the housing receive, store or process the digitized vibration signal and/or the digital tachometer signal, for the purpose of predictive maintenance. The housing of the data collector also holds a display and input keys, so that an operator may use the same hand for holding and controlling the data collector, and for holding the integrated laser tachometer. This frees a hand for holding an accelerometer or for other purposes. Use of a data collector with an integrated laser tachometer is thus substantially more convenient than using a data collector with a separate, nonintegrated laser tachometer attachment.

Abstract: A method is provided for measuring the surface travel time of a surface wave between first and second points on a surface. First and second spaced apart transducers are disposed substantially perpendicular to a surface. The direct travel times for each transducer are determined, then a total travel time from the first transducer to the second transducer is measured. The direct travel times are subtracted from the total travel time to produce the actual travel time between the points on the surface.

Abstract: A transducer calibration apparatus and method for transforming both previously established transducer parameters for a transducer calibrated to a first target object material and measured transducer parameters for the transducer monitoring a second different target object material into a calibration parameter and transforming the output of the transducer and thus, the use of the transducer, from the first target object material used to calibrate the transducer to the second different target object material being subsequently monitored by the transducer by linearizing the output of the transducer into gap values as a function of the calculated calibration parameter and then, generating alarms based on the linearized output of the transducer exceeding established limits and using the alarms to automatically shut down a machine being monitored by the transducer and/or automatically annunciate machine problems to personnel.

Abstract: A method and apparatus are provided for performing non-contact inspection of large concrete structures such as dams. A phrased array acoustic source transmits an acoustic wave onto the concrete structure. A laser transmitter-receiver unit transmits a laser beam onto the surface of the structure such that the beam is modulated by the acoustic wave and reflected back to the receiver portion of the unit. The acoustic wave will be distorted by defects or anomalies in the concrete structure and this will affect the signal content of the received laser beam. The laser beam is ultimately converted into a two-dimensional image or a three-dimensional tomographic image for further processing.

Abstract: A gas-concentration measuring apparatus for measuring the concentration variation of gas residing in a target region. The gas-concentration measuring apparatus comprises an ultrasound-transmitter adapted to transmit an ultrasound in response to an ultrasound-generating signal having a rate of voltage change equal to or greater than a slew rate of an operational amplifier, and further adapted to output the ultrasound-generating signal. An ultrasound-receiver adapted to receive the ultrasound wave passed through the gas residing in the target region, and further adapted to convert the received ultrasound into an electrical signal serving as a received ultrasound signal is provided. A gas-concentration determiner adapted to input the ultrasound-generating signal and the received ultrasound wave signal into the operational amplifier to generate an amplified transmitting-side chopping wave and an amplified receiving-side chopping wave is further provided.

Abstract: In a nondestructive ultrasonic testing method for an implementation in a testing device, defects are installed in a testing area of a structural part by determining reflections on inhomogeneities in the a testing area of the structural part. A least one ultrasonic transmitter is provided for coupling ultrasonic excitations into the structural part and at least two ultrasonic receivers are installed for receiving structure responses to the excitations coupled into the structure. A number of testing points being are determined and for each testing point and each location of the ultrasonic receivers, expectancy range data are determined and stored for signal forms being implemented in the testing device. When an inhomogeneity is present in the respective testing point, excitations are reflected thereon and are measured by the respective ultrasonic receiver. The received reflection data are compared with the stored expectancy ranges to determine the location of a defect.

Abstract: A device for examining materials, in particular trees, other kinds of wood, and concrete, with a pulse generator (1) for generating a pulse that can be introduced into the material (2), with at least one sensor (3) adapted for being associated to the material (2) for detecting the pulse, and with an electronic evaluation device (4) for discriminating the pulse from interference pulses, is designed and constructed with respect to a universal application to even large test pieces of the material (2) being examined in such a manner that an electronic evaluation device (4) is associated to each sensor (3).

Abstract: The present invention relates generally to a system of addressing pipeline anomalies prior to failure of pipeline integrity, and particularly to a pipeline inspection system integrating a novel serviceability acceptance criteria for pipeline anomalies, specifically wrinkles, with an improved method of correlating ultrasonic test data to actual anomaly characteristics.

Abstract: The speed of sound c is determined in a material as a function of the temperature T by heating an end of an elongated sample body of the material of the temperature and determining the time difference for the receipt of echoes from two reflective zones at the heated end. The opposite end of the body is cooled in a water bath which can couple an ultrasonic test head to the body.

Abstract: The invention relates to a method for non-destructive testing of materials, in which at least two differently guided waves (modes) are produced in the solid body, each at at least one specified angle, the measured reflection values are placed in relation to a reference echo in order to obtain a relative reflection value, and the relative reflection values of the individual modes are again placed in relation to one another, thereby enabling the size and type of the defects to be determined.

Abstract: A method and system for determining meat quality in cattle is provided. In preferred embodiments the method comprises obtaining an ultrasound measurement of a cattle specimen between the 12th rib and 13th rib at weaning age. The ultrasound measurement is utilized to extrapolate a harvest quality parameter. Based on the harvest quality parameter, and preferably a yield grade, the specimen is categorized. Particularly preferred harvest quality parameters are ribeye area, fat thickness, intramuscular fat and ribeye shape. Method for determining tenderness, stress and intramuscular fat are described and claimed.

Abstract: A nondestructive inspection method for composite structures, including thick core structures, is disclosed that imparts a vibration force into the structure and analyzes the response over a range of frequencies to find possible damaged areas. The composite structure is struck to induce vibration at a series of test points and the response of the composite structure as a function of acceleration at each test point is measured. The structural anomalies in the composite structure occur at structural stiffness irregularities near anomalies and are detected with a Gapped Smoothing Method operating on the data and plotting a structural irregularity index as a function of frequency and position.

Abstract: An ultrasonic inspection method includes exciting a first set of transducers in an array to introduce ultrasonic energy into a component, generating a number of echo signals using a second set of transducers in the array as receive elements, and processing the echo signals. The first and second sets of transducers are exclusive of one another, and the first and second sets of transducers are interleaved.

Abstract: A system for inspecting a refractory furnace having an outer shell and an inner refractory brick lining includes a stress wave generator for generating stress waves that propagate through the outer shell and the refractory brick lining. A stress wave sensor senses reflected stress waves returning to the outer shell. A processing unit in communication with the stress wave sensor processes output generated by the stress wave sensor to generate data representing the condition of the refractory brick lining. In this manner, the location and geometry of anomalies within the refractory brick lining can be determined without requiring the refractory furnace to be shut down.

Abstract: A damage evaluation method and apparatus of a metal material which is capable of determining whether a flaw in the metal sample is originated by the creep damage or in the manufacturing process, and also capable of estimating a remaining life of the metal component. The damage evaluation method of a metal material by the present invention is a method for evaluating a flaw in the metal sample comprising the steps of mounting onto a metal surface including an internal flaw and on both sides of the flaw a transmitting probe for transmitting an ultrasonic waves and a receiving probe for receiving the ultrasonic waves, transmitting the ultrasonic waves towards the internal flaw and receiving the diffracted wave from the flaw for determining whether or not a flaw is present in the metal, based on the analysis of the distribution of the diffracted waves and an analysis of the sample as to whether voids (creep voids) are present and, if present, the distribution of the voids.

Abstract: Material analysis apparatus and method, particularly of use in detecting barely visible impact damage but also of use to detect other material characteristics. The apparatus includes a function generator which provides a sinusoidal signal to an ultrasonic amplifier as well as to a PC. The PC is connected to an infrared camera. The sinusoidal signal is fed into the amplifier and causes two probes attached to the sample of material to emit ultrasonic energy at the modulated frequency. Ultrasonic energy from the two probes then enters the sample by means of mechanical coupling and an image of the resulting thermal radiation is captured by the infrared camera and transferred to the PC for further processing and analysis.

Abstract: An ultrasound imaging system and method for making a harmonic image of a good SNR (signal-to-noise ratio) by effectively removing fundamental frequency components through a pulse-compressing using weighted chirp signals, is provided. The ultrasound imaging system includes: a transducer array for converting weighted chirp signals to ultrasound signals, and transmitting the ultrasound signals to a target object; a receiver for receiving signals reflected from the target object; a pulse-compressor for selectively pulse-compressing fundamental frequency components or harmonic frequency components in the reflected signals; and a producer for producing receive-focused signals from the pulse-compressed signals. Therefore, the ultrasound imaging system can form ultrasound image using the fundamental frequency components, and can form ultrasound harmonic image using the harmonic frequency components according to 2fo-correlation method or 2fo-correlation (PI) method.

Abstract: The product comprises a sensor (1) via which a measured quantity that corresponds to a reactive resistance can be furnished within a measuring range. The product also comprises a matching network (2) and a surface wave element (3). The sensor (1) is connected to a first reflector (4) of the surface wave element (3) via the matching network (2). The first reflector (4) forms, together with the matching network (2) and the sensor (1), a resonator which, for a value of the measured quantity within the measuring range, has a resonance with regard to a reflection of an acoustic surface wave on the first reflector (4). The invention also relates to a method for determining the measured quantity and to a corresponding system.

Abstract: The invention is directed to an ultrasonic testing system. The system tests a manufactured part for various physical attributes, including specific flaws, defects, or composition of materials. The part can be housed in a gantry system that holds the part stable. An energy generator illuminates the part with energy and the part emanates energy from that illumination. Based on the emanations from the part, the system can determined precisely where the part is in free space. The energy illumination device and the receptor have a predetermined relationship in free space. This means the location of the illumination mechanism and the reception mechanism is known. Additionally, the coordinates of the actual testing device also have a predetermined relationship to the illumination device, the reception device, or both.

Abstract: Described herein is a technology for facilitating diagnosis of the operation of devices or machines based, at least in part, upon the acoustics of such.

Abstract: A transducer-based sensor system including a drive signal generator for generating a drive signal, a transducer coupled to the drive signal generator and configured to receive the drive signal, a mixer coupled to the transducer and configured to receive output from the transducer where such output results at least in part from physical movement of the transducer, and a diplexer operatively coupled with an output of the mixer and configured to present a substantially matched output impedance to the mixer over an operative range of output frequencies.

Abstract: An apparatus determines how well a semiconductor wafer (4) is clamped to a support member (1). The apparatus has at least one ultrasonic transducer (2a,2b,2c,2d) configured to emit ultrasonic energy (3) toward an interface between the wafer (4) and the support member (1) so that the interface generates echo signals, and a data processing unit (11) configured to analyze the echo signals to arrive at a determination as to how well the semiconductor wafer (4) is clamped to the support member (1) before semiconductor process is started. A first method ensures that a wafer (4) is securely clamped to a support member before a semiconductor process is started.A second method verifies proper de-clamping of a semiconductor wafer (4) from a support member (1) before the semiconductor wafer (4) is removed from the support member (1) upon completion of a semiconductor process.

Abstract: In a measurement system wherein time-varying physical signals containing frequency information related to a physical parameter of an object are measured to obtain corresponding time-varying measurement signals, a method and system are disclosed for processing the measurement signals to obtain a value for the physical parameter by first extracting the frequency information from the measurement signals. The frequency information includes at least one desired frequency. The physical signals are electromagnetic signals. The object is a film such as a layer formed on a substrate, the physical parameter may be thickness of the layer.

Abstract: Use of a single end testing of stems of felled trees whereby by inducing a sonic wave with an impact and by reference to detected reflections and with a knowledge of the length of the stem the stiffness and/or strength characteristics of the stem or logs to be cut therefrom can be derived. A preferred procedure is a determination of the fundamental frequency f0 which relates to velocity V, the speed of longitudinal compressional motions along the stem, and L, the length of the stem, as follows: V=2Lf0. From that value V or a function of V can be derived an indicator of stiffness and/or strength.

Abstract: A system and technique for determining fluid properties includes an ultrasonic transducer 30 on a first surface 42 of a solid member 40. An opposed second surface 44 of the member 40 is in contact with a fluid 25 to be monitored. A longitudinal ultrasonic pulse is delivered through the solid member, and a multiplicity of pulse echoes caused by reflections of the ultrasonic pulse between the solid-fluid interface and the transducer-solid interface are detected and processed by a processing apparatus 22. The apparatus 22 determines the decay rate of the detected echo amplitude as a function of echo number and compares this value to a calibrated decay rate to determine an acoustic property of the fluid. The speed of ultrasound in the fluid is also determined and the fluid density is determined as a function of the speed of ultrasound and the determined acoustic property.

Abstract: The invention relates to a method for verifying thickness modulations, in particular watermarks, in or on sheet material. To diminish the influence of disturbances from the surroundings and reduce the adjustment effort during production and maintenance of corresponding measuring systems, the sheet material is subjected to sound, in particular ultrasound, the sound transmitted through the sheet material and/or reflected on the sheet material is measured at a plurality of places on the sheet material, at least one value characteristic of the transmitted and/or reflected sound is generated for each of the places, and the thickness modulations are verified by comparing the values with predetermined reference values.

Abstract: The invention provides a system for measuring, characterizing, verifying and position-determining material properties of a selected object to be measured, in particular thickness distribution. A mobile measuring unit which is manouvered and operated manually or with the aid of a remote-control transport device senses half-wave resonance in objects to be measured and computes the thickness distribution. A new, accurate, partly acoustic positioning system determines the position of the measured area.

Abstract: A method for distinguishing multiple targets using time-reversal acoustics. Time-reversal acoustics uses an iterative process to determine the optimum signal for locating a strongly reflecting target in a cluttered environment. An acoustic array sends a signal into a medium, and then receives the returned/reflected signal. This returned/reflected signal is then time-reversed and sent back into the medium again, and again, until the signal being sent and received is no longer changing. At that point, the array has isolated the largest eigenvalue/eigenvector combination and has effectively determined the location of a single target in the medium (the one that is most strongly reflecting). After the largest eigenvalue/eigenvector combination has been determined, to determine the location of other targets, instead of sending back the same signals, the method sends back these time reversed signals, but half of them will also be reversed in sign.

Abstract: The invention relates to a device for evaluating signals comprising a signal detection unit (26) that detects a measurement signal (UE). A measured value evaluation unit (43) evaluates measurement signals (UE) located inside a measurement window (TM1, TM2, TS1, TS2). Means (35), (37), (39) are provided for establishing the measurement window (TM1, TM2, TS1, TS2) and they establish the measurement window (TM1, TM2, TS1, TS2) according to the measurement signal (UE).

Abstract: Embodiments of the invention provide an algorithm for enhancing the transit time measurement of an ultrasonic wave through a fluid, and criteria for evaluating the suitability for various waveforms with regard to noise rejection. The transit time calculation provides a greater noise immunity and accuracy than techniques used in the prior art, and allows a measure of weighting of dispersed signals with different arrival times. The transit time calculation utilizes either the transmitted signal or the measurement of a reference system, the calculation of the squared convolution of this signal with the received signal, and the calculation of the transit time from the time-weighted squared convolution signal over a suitable interval defined by the minimums of the squared convolution signal. In the case of dispersion where the arrival times are symmetrically displaced around a mean transit time, or if asymmetric dispersion is suitably within the main lobe, the calculation properly weights the composite signal.

Abstract: There is described apparatus for inspecting a non axi-symmetric elongate body comprising: at least one exciter array having a plurality of wave exciters operable to couple to an exterior surface of said elongate body; a driver unit operable to generate driving signals to excite said plurality of wave exciters wherein each driving signal to a respective wave exciter of said array is weighted with respect to driving signals to other wave exciters in said array such that a guided acoustic wave mode is excited; a receiving unit having a plurality of wave exciters in said array such that a guided acoustic wave mode is excited; a receiving unit having a plurality of wave receivers capable of receiving reflected guided acoustic waves; an analysis unit operable to analyse received waves to assess a condition of said non axi-symmetric elongate body.

Abstract: A bubble detector utilizes an ultrasonic transducer to sample bubbles as they pass the transducer. The envelope of the return signal is analyzed to determine the volume of each sampled bubble. If the total volume of bubbles sampled within a certain period of time exceeds a desired maximum volume, the bubble detector may initiate a system shut down. A bubble detector can be evaluated or calibrated by introducing bubbles into a conduit, detecting the bubbles introduced into the conduit using visual inspection or a bubble detector of known resolution and comparing the results with the examination of a bubble detector under evaluation.

Abstract: Ultrasonic testing techniques may involve the measurement of ultrasonic waves from the tested part. These waves may reflect from surfaces of various layers within the part. Further, these waves may reflect from faults, defects, voids, fractures, and others. As such, the measured ultrasonic wave is a complex mix of these reflections. One method for detecting flaws, defects, and others may be to express the signal in terms of a set of basis functions. These functions may be summed to produce the measured signal. Further, basis functions may be chosen such that a select set of the basis functions characterize the fault and/or defect. In one exemplary embodiment, the coefficients associated with the basis function may be non-zero when a defect is present. As such, a defect may be detected quickly and automatically.

Abstract: The invention relates to an ultrasonic sensor system, especially for controlling a resistance welding process. Said system comprises at least one receiver which is used to detect the ultrasonic signals from the area to be examined. At least two piezoelectric sensors (31, 32) are used as a receiver and are arranged in such a way that their polarisation direction vectors indicate various directions, said vectors being projected in a plane perpendicular in relation to the propagation direction of an ultrasonic wave to be detected.

Abstract: An ultra sonic sound measurement is used to determine the thickness of a partial layer in a multi-layered structure with reduced boundary surface reflections. A plurality of transmission pulses are produced on a predetermined point on the structure with the help of an ultra sonic probe head. The resulting echo signals associated with a transmission pulse are recorded digitally as an HP image. A plurality of wall thickness echo periods from different running periods are superimposed in a homologous manner with the aid of a computer program.

Abstract: A method for ultrasound measurement of the layer thickness of thin-walled tubes includes utilizing a high-frequency probe (more than 40 MHz) with a coupling area having a planar area surface. The area surface is coupled to the tube surface that is wetted with a coupling agent by way of a contact method. The inventive method is used for duplex or liner layers of 0.15 mm thickness of reactor fuel cladding tubes.

Abstract: A gas-concentration measuring apparatus for measuring the concentration variation of gas residing in a target region The gas-concentration measuring apparatus comprises an ultrasound-transmitter adapted to transmit an ultrasound in response to an ultrasound-generating signal having a rate of voltage change equal to or greater than a slew rate of an operational amplifier, and further adapted to output the ultrasound-generating signal. An ultrasound-receiver adapted to receive the ultrasound passed through the gas residing in the target region, and further adapted to convert the received ultrasound into an electrical signal serving as a received ultrasound signal is provided. A gas-concentration determiner adapted to input the ultrasound-generating signal and the received ultrasound signal into the operational amplifier to generate an amplified transmitting-side chopping wave and an amplified receiving-side chopping wave is further provided.

Abstract: A case of tilt angle measuring apparatus is composed of a case body for housing ultrasonic sensors and a cover for covering a top of the case body, and the case body includes a bottom plate having windows for exposing the ultrasonic wave transmitting/receiving faces of the ultrasonic sensors, a side plate extending upward from the peripheral edge of the bottom plate and abutting against the bottom surface of the cover, and horn parts extending downward from the bottom plate so as to surrounding the windows.

Abstract: A method and system for determining meat quality in cattle is provided. In preferred embodiments the method comprises obtaining an ultrasound measurement of a cattle specimen between the 12th rib and 13th rib at weaning age. The ultrasound measurement is utilized to extrapolate a harvest quality parameter. Based on the harvest quality parameter, and preferably a yield grade, the specimen is categorized. Particularly preferred harvest quality parameters are ribeye area, fat thickness, intramuscular fat and ribeye shape. Methods for determining tenderness, stress and intramuscular fat are described and claimed.

Abstract: A method for the determining ultrasonic sound propagation speed and wall thickness of a tubular object. Time-domain and frequency-domain analyses are used, where the latter can determine acoustic dispersion if the specimen is made up of a dispersive material. Data is sensed from a series of transmitted ultrasonic waves, some of which are reflected. The data can be used to calculate speed of sound in the tube, as well as wall thickness. Inherent in the data is the speed of the ultrasonic wave; accordingly, correction for temperature variations in the tube is not required. The calculations based on measured speed of sound quantities produces more accurate results than in calculations where the speed of sound in the specimen is assumed.

Abstract: A method and apparatus for analyzing a deposited layer on the inner surface of a fluid container wall having inner and outer surfaces are disclosed. One embodiment of the method comprises (a) transmitting an acoustic signal from a transmitter at a first distance from the outer surface of the wall; (b) receiving a first received signal A, comprising a reflection from the wall outer surface; (c) receiving a second received signal B, comprising a reflection from the wall inner surface; (d) receiving a third received signal C from the wall inner surface; (e) calculating a coefficient Rwp from A, B and C, and (f) calculating a coefficient Rpd from A, B and Rwp, and calculating the acoustic impedance of the deposited layer Zd from Rwp, Rpd, and Zw, where Zw is the acoustic impedance of the material between the transmitter and the wall outer surface.

Abstract: An acoustic monitoring method and system in laser-induced optical breakdown (LIOB) provides information which characterize material which is broken down, microbubbles in the material, and/or the microenvironment of the microbubbles. In one embodiment of the invention, femtosecond laser pulses are focused just inside the surface of a volume of aqueous solution which may include dendrimer nanocomposite (DNC) particles. A tightly focused, high frequency, single-element ultrasonic transducer is positioned such that its focus coincides axially and laterally with this laser focus. When optical breakdown occurs, a microbubble forms and a shock or pressure wave is emitted (i.e., acoustic emission). In addition to this acoustic signal, the microbubble may be actively probed with pulse-echo measurements from the same transducer. After the microbubble forms, received pulse-echo signals have an extra pulse, describing the microbubble location and providing a measure of axial microbubble size.

Abstract: The invention relates to a device for distance measurement, comprising a transmission element (9) for emitting pulsed acoustic or electromagnetic waves. Said transmission element is provided at a first end of a distance (L) or at a known distance from said first end. The device contains a receiving element (13) for the emitted waves. Said receiving element (13) receives said waves at a second end of the distance (L) or, after reflection at the second end, at the first end. An evaluation and control unit (11) calculates the distance (L) from the running time and the signal speed. According to the invention, a telescope tube (3) with two engaging tube elements (5, 7) is used between the first and second end. The transmission element (9) and the receiving element (13) are arranged on the tube elements (5, 7) respectively or are coupled thereto via waveguides. One of the tube elements can also be coupled to a displaceable element which can change location.

Abstract: An ultrasound inspection apparatus particularly adapted to examine containers (sealed or unsealed) containing a liquid or solid bulk material. The apparatus has an overall configuration of a hand held pistol with a front transducer contact surface that is positioned against a front wall of the container. An ultrasound pulse is transmitted from the apparatus to be reflected from a back wall of a container being investigated. The received echo pulse is converted to a digital waveform. The waveform is analyzed relative to temperature, travel distance of the pulse(s), and time of travel to ascertain characteristics of the liquid or other materials and to provide identification of the same.

Abstract: The x- and y-direction vibration components of radial vibration of a rotational shaft 106 obtained by measurement from x and y directions are transformed into frequency sample values {XkYk, k=0, 1, . . . N−1} by discrete Fourier transform. RMS amplitude values {2½|Fki(2j&pgr;/M)|, j=0, 1, . . . M/2−1} are calculated at azimuths {&thgr;j=2j&pgr;/M, j=0, 1, . . . M/2−1} corresponding to 0 to &pgr; on the basis of frequency sample values at frequency points {ki, i=1, . . . P} corresponding to specific frequencies {fi, i=1, . . . P} of NRRO vibration components selected from the x- and y-direction frequency sample values obtained by the discrete Fourier-transform. RMS evaluation values Aki are selected from these RMS amplitude values.

Abstract: A system for determining a property of a fluid based on ultrasonic diffraction grating spectroscopy includes a diffraction grating on a solid in contact with the fluid. An interrogation device delivers ultrasound through the solid and a captures a reflection spectrum from the diffraction grating. The reflection spectrum including a diffraction order equal to zero exhibits a peak whose location is used to determine speed of sound in the fluid. A separate measurement of the acoustic impedance is combined with the determined speed of sound to yield a measure of fluid density. A system for determining acoustic impedance includes an ultrasonic transducer on a first surface of a solid member, and an opposed second surface of the member is in contact with a fluid to be monitored. A longitudinal ultrasonic pulse is delivered through the solid member, and a multiplicity of pulse echoes caused by reflections of the ultrasonic pulse between the solid-fluid interface and the transducer-solid interface are detected.

Abstract: All independent acoustical physical constants (elastic constants, piezoelectric constants, dielectric constants and density) of a material are predetermined as a function of its chemical composition, and the calibration line between the acoustic velocity for each of the substrate crystal plane, the propagation direction and the propagation mode, and other chemical and physical properties is numerically calculated with ease without making any experiments.

Abstract: An ultrasonic moving-speed measuring system comprises a piezoelectric substrate, a thickness-vibration mode transducer, an interdigital transducer, and a signal analyzer. The piezoelectric substrate, the thickness-vibration mode transducer, and the interdigital transducer form a transducing assembly. When an input electric signal with a carrier frequency is applied to the thickness-vibration mode transducer, a longitudinal wave is radiated into a medium that is in touch with the bottom of the transducing assembly. If the longitudinal wave is reflected at a material in the medium, a delayed electric signal with a Doppler frequency is detected at the interdigital transducer via a mode conversion from a reflected longitudinal wave to a leaky Lamb wave. The moving speed of the material is sensed at the signal analyzer in terms of a difference between the carrier- and Doppler frequencies.