Abstract: An ultrasonic sensor which has a thin planar sheet of material forming a Lamb wave propagation medium, the sheet having a thickness which is no greater than about twenty microns. The sensor also includes a Lamb wave generator for generating Lamb waves in the propagation medium and an output device for producing an electrical signal representative of the propagation characteristics of the Lamb waves propagating along the propagation medium. A measuring device is included in the sensor to measure selected characteristics of the output electrical signal. The propagation medium has some physical characteristics that are determined by the value of a measurand acting on the medium and the determined physical characteristics determine the propagation characteristics of the Lamb waves which are propagated along the medium. When the sensor is acted on by a measurand to determine the physical characteristics of the propagation medium, the characteristics of the electrical signal are also determined.

Abstract: A system for creating a control signal having a value indicative of the position of the lateral edge of a moving web wherein the system creates a succession of ultrasonic pulses from a transmitter, each of the pulses being created at a known transmit time in response to a transmit signal with the pulses each having a number of oscillations defining a pulse envelope having a pulse start portion. The system directs the ultrasonic pulses toward an ultrasonic receiver along a selected path whereby the position of the lateral edge of the web in the path determines the energy of the pulse as it is received by the receiver and converts the received pulse into an electronic signal having an amplitude determined by the energy of the received pulse. The receiver is spaced from the transmitter a predetermined distance causing the pulses to be received by the receiver at a given time after the transmit signals for a given ambient temperature.

Abstract: An ultrasound densitometer for measuring the physical properties and integrity of a member in vivo includes a transmit transducer from which acoustic signals are transmitted, and a receive transducer which receives the acoustic signals after they have been transmitted through the member and/or a material with known acoustic properties. The densitometer allows the physical properties of a member to be measured without having to determine the distance between the transducers. The densitometer is able to measure the physical properties and integrity of the member from the transit time of acoustic signals through the member and/or by determining the absolute attenuation of at least one specific frequency component of acoustic signals transmitted through the member.

Abstract: A method and apparatus for detecting a blockage in a cored passage of a hydraulic valve casting includes a sound generating device disposed within the spool bore and communicating with the passageway so that a sound wave may be introduced into the passageway and a sound detecting device disposed within the spool bore and communicating with an opposite end of the passageway so that the level of sound transmitted through the passageway may be detected.

Abstract: An ultrasound densitometer for measuring the physical properties and integrity of a member in vivo includes a transmit transducer from which acoustic signals are transmitted, and a receive transducer which receives the acoustic signals after they have been transmitted through the member and/or a material with known acoustic properties. The densitometer allows the physical properties of a member to be measured without having to determine the distance between the transducers. The densitometer is able to measure the physical properties and integrity of the member from the transit time of acoustic signals through the member and/or by determining the absolute attenuation of at least one specific frequency component of acoustic signals transmitted through the member.

Abstract: Ultrasound diagnostic equipment for diagnosing a region of interest of an organ by using a scattering coefficient and an attenuation slope comprises a scattering power calculation unit for calculating a scattering spectrum of the region of interest, a cumulative attenuation slope calculation unit for calculating a cumulative attenuation slope of the intervening tissue between a body surface and a position of blood close to the region of interest by using a scattering coefficient of blood which is previously known, and a scattering coefficient calculation unit for calculating a scattering coefficient of the region of interest by using the calculated cumulative attenuation slope of the intervening tissue between body surface and the blood close to the region of interest.

Abstract: The weight fractions of the phases of a composite material working specimen are determined nondestructively by first performing a sufficient number of nondestructive and destructive calibration measurements on the properties of calibration specimens. The information learned from the calibration specimens is used in combination with nondestructive measurements of the working specimen to determine the fractions of the phases therein, without damaging the working specimen. In one version of this approach, ultrasonic measurements are used to determine fractions of the fiber and matrix in a nonmetallic composite material.

Abstract: A method of determining low density deposits on the inner surface of a boiler tube comprises the generation of ultrasonic energy which is directed from the outer surface of the tube to the inner surface of the tube. The energy is reflected back and forth between the inner and outer surfaces with each reflection of the inner surface loosing energy by attenuation into any existing low density deposit. The first and fourth reflections are measured and digitized for analysis to determine the amount of attenuation. The amount of attenuation is representative of the low density deposit on the inner surface of the tube. The tube is preferably empty of water to avoid transmission of ultrasonic energy through water in the tube.

Abstract: A meat carcass is inspected ultrasonically to determine its fat-to-lean ratio and to obtain a three-dimensional computer image of the interior of the carcass showing the location, shape and nature of the various pixels of different materials, (fat, lean, and possibly also bone, abscesses or other tissues) in the carcass. These results are achieved by passing ultrasonic pulses into and through the carcass, measuring the timing of both transmitted pulses and return pulses that are reflected from the carcass surfaces and from successive planes between the internal pixels, and measuring the relative intensities of the reflected pulses, the latter measurement providing data on the attenuation coefficients of the various pixels from which their nature can be determined. The velocities of the ultrasonic pulses in the different materials being known, as well as their attenuation coefficients, a computer can calculate the fat-to-lean ratio and can construct the desired three-dimensional image.

Abstract: This invention relates to measurements of characteristics of a comminuted material by an ultrasonic method. The method of monitoring parameters of a solid phase of suspension comprises the steps of producing a Lamb wave and gamma-radiation and passing them respectively through a test medium (2) along the wall of a measuring vessel (1) and through the test medium (2) placed therein, measuring the amplitude of the Lamb wave and the intensity of gamma-radiation, while using, as the test medium, separately a standard liquid and the analyzed suspension to find the parameters of the solid phase of suspension by way of the ratio of the measured values.

Abstract: A method of identification and quantification of absorbed chemical species by measuring changes in both the velocity and the attenuation of an acoustic wave traveling through a thin film into which the chemical species is sorbed. The dual output response provides two independent sensor responses from a single sensing device thereby providing twice as much information as a single output sensor. This dual output technique and analysis allows a single sensor to provide both the concentration and the identity of a chemical species or permits the number of sensors required for mixtures to be reduced by a factor of two.

Abstract: A method for the situ measuring of a sample of a porous material having a gaseous fluid and fine granular material located within its pores and, in particular, for determining the concentration of the fine granular material within the sample. The method includes the steps of generating a first acoustic wave signal of known amplitude and phase velocity, directing the first acoustic wave signal through the sample, receiving a second acoustic wave signal representing the first acoustic wave having passed through the sample, and determining the concentration of the fine granular material in the sample from the changes between the first acoustic wave signal and the second acoustic wave signal.

Abstract: A method for measuring parameters of solid phase of slurries having the following steps: forming ultrasonic oscillations and emitting them into a fluid under study, forming the Lamb waves and directing them into a wall of a vessel containing the fluid under study, forming acoustic currents and radiation pressure of sonic radiation in the fluid under study, and measuring amplitude and length of pulses of ultrasonic oscillations that pass through the fluid under study and the Lamb waves that pass through a predetermined distance along the wall of the vessel containing the fluid under study without and with the action of the acoustic currents and radiation pressure of sonic radiation, the values of which are used for the assessment of concentration of solid phase of the fluid under study. An apparatus for carrying out the method has two measurement channels each having a logarithmic converter, a subtraction unit and a division unit.

Abstract: An ultrasound densitometer for measuring the physical properties and integrity of a member in vivo includes a transmit transducer from which acoustic signals are transmitted, and a receive transducer which receives the acoustic signals after they have been transmitted through the member and/or a material with known acoustic properties. The densitometer allows the physical properties of a member to be measured without having to determine the distance between the transducers. The densitometer is able to measure the physical properties and integrity of the member from the transit time of acoustic signals through the member and/or by determining the absolute attenuation of at least one specific frequency component of acoustic signals transmitted through the member.

Abstract: In ultrasonic echoscopy, when an object to be examined has overlying layers of a medium (for example, fat, muscle, skin or bone) which have different ultrasonic transmission characteristics from those of the object, the echogram of the object is usually distorted. To reduce that distortion, the present invention uses a transducer comprising an array of ultrasonic transducer elements operated in a higher resolution mode than its normal imaging mode, to obtain information about the geometry of the overlying layers. Using this information and a knowledge of the transmission characteristics of the overlying layers, amplitude and phase corrections are calculated, to enable the transducer, when operated in its normal imaging mode, to generate a required beam of ultrasound. The corrections are then applied and an echogram of the object, with reduced distortion, is obtained while operating the transducer in its normal imaging mode.

Abstract: A method and apparatus is disclosed for the non-destructive measurement of die-attach quality in packaged integrated circuit. The apparatus is used in a production line and uses acoustical pulses to generate signals from within the integrated circuit indicative of the die-attach quality.

Abstract: An ultrasound densitometer is disclosed in which ultrasonic transducers are located spaced apart in a water bath into which the heel of a person may be inserted. The transit time of an ultrasonic pulse through the water can be compared to the time for a similar pulse with a heel inserted. A novel clinical indicia for bone integrity value has been developed to provide a single numerical indication related both to the speed of sound travel in the member and the ultrasonic broadband attenuation in the member. The bone integrity value numeral based on measurements in the os calcis has been found to correlate well with conventional measurements of spinal bone mineral content.

Abstract: A stress wave load cell comprises a propagation member to which is acoustically coupled a transducer. Electrical pulses are supplied to the transducer from a pulse generator and the electrical pulses are converted into stress wave signals which propagate through the propagation member. The transducer also detects the stress waves after propagation through the propagation member and supplies an electrical signal to processor which gives a measure of the load applied to the load cell.Damping members which have profiled surfaces are caused to move into damping contact with the propagation members when a load is applied to the load cell. The damping members damp the propagation of the stress waves in the propagation member and the damping is proportional to the area of damping contact, the area of damping contact increases with the load applied. May be used to measure tensile load or compressive load and may be used as a touch sensitive panel.

Abstract: On emission and/or on reception, circuits impose on the signals emitted and/or received, delays in accordance with a random or pseudo-random delay law. On emission, just as on reception, this delay law is superposed on that for focusing and angulation of the signals. On emission, the law is obtained, for example, by causing variation of the instants of triggering of the generators of signals for the excitation of the transducers. On reception, either parallel random delay lines or conditional inversion circuits are included. These circuits permit the breakdown of the coherence of the ultrasonic waves on emission, on reception, or on both simultaneously, may be used in an analogue version, as well as in a digital version.

Abstract: Method and apparatus for the non-destructive monitoring of the time dependent curing of an advanced composite positioned within an autoclave where it is subjected to varying pressures and elevated temperatures over a predetermined time period. A tool receiving the uncured advanced composite for receiving an acoustic wave guide which directly coupled to the composite. Ultrasound pulses are directed through the acoustic wave guide and the amplitude of the reflected pulses indicate changes in the modulus of the composite during the cure.

Abstract: Reference materials of differing indices of refraction or acoustic impedances are incorporated into liquid compositions to monitor the solidification process of these liquid compositions. Light or acoustic waves are used to indirectly measure the difference between the index of refraction or acoustic impedance of the solidfying composition and the reference material. The method provides an accurate in situ indication of the completion of the solidification process as well as a monitor of the degree of solidification during the solidification process.

Abstract: The present invention provides a novel method and apparatus which allows concomitant imaging and rapid axial beam translation measurements used to calculate the attenuation characteristics of a target body. The present invention employs an ultrasonic scanner which contains a plurality of matched transducer elements. These elements are staggered on a mechanism which sequentially places each transducer opposite an acoustic window at axially spaced positions along a common axis. The present invention also enables axial beam translation techniques to be adapted to current ultrasonic imaging systems.

Abstract: Tissue signatures are obtained from first and second order statistics of an image texture to discriminate between different normal tissues and to detect abnormal conditions. These signatures described intrinsic backscatter properties of the tissue imaged and are used as the basis of an automatic tissue characterization algorithm. A device for on-line classifying of the texture of an image measures a total of four first and second order statistical properties of echo signals of a region of interest (ROI) selected by an operator, the echo signals being contained in an image memory. These can be used to obtain the tissue signatures, to detect low contrast lesions by machine, and to produce parametric images.

Abstract: An ultrasonic sound generator and receiver are spaced apart from each other so as to receive a projecting portion of a cassette in which a liquid carrying passage is defined by a flexible membrane. The liquid carrying passage in the projecting portion fits between the ultrasonic sound generator and receiver, with opposite sides of the flexible membrane in contact with the sound generator and sound receiver. The sound generator and sound receiver each comprise a substrate having a layer of conducting material. Two electrically isolated regions are defined on the conductive layer, and a piezoelectric chip is electrically connected between the two regions. An electrical signal applied between the first and second regions excites the piezoelectric chip on the sound generator, causing it to generate an ultrasonic signal, which is transmitted through the liquid carrying passage.

Abstract: A system for analyzing bone conditions, particularly (but not solely) for diagnosing osteoporosis and periodontal bone disease in humans. An ultrasonic signal (generally a pulse) having components in a range from about 50 kHz to about 600 kHz (and preferably to about 3 MHz) is launched transdermally into a bony member such as the patella, and received after passage therethrough. Scattering of the incident wave energy in the bony member, and absorption and phase delay in the tissue, cause the transmission to vary in both amplitude and phase as a function of frequency. A multivariable analysis is performed on a plurality of variables characterizing the signals transmitted through, reflected from or scattered by the bony member and soft tissue. The measured parameter values characterize the bone architecture and are compared with the statistics for one or more groups having known bone condition, to yield a probabilistic diagnosis of bone condition.

Abstract: An ultrasound densitometer for measuring the physical properties and integrity of a member in vivo includes a transmit transducer from which acoustic signals are transmitted, and a receive transducer which receives the acoustic signals after they have been transmitted through the member and/or a material with known acoustic properties. The densitometer allows the physical properties of a member to be measured without having to determine the distance between the transducers. The densitometer is able to measure the physical properties and integrity of the member from the transit time of acoustic signals through the member and/or by determining the absolute attenuation of at least one specific frequency component of acoustic signals transmitted through the member.

Abstract: A procedure for analyzing air content of a liquid, e.g. pulp slurry, wherein the ratio I.sub.att /I.sub.sc between ultrasound attenuation and scattered ultrasound attenuation and/or the logarithm log (I.sub.att /I.sub.sc) is determined. The respective measuring apparatus comprises an ultrasound transmitter (1) and an ultrasound receiver (2) and a scattered ultrasound receiver (3), the latter being disposed to measure members (4) for determining the ratio I.sub.att /I.sub.sc and/or the logarithm log (I.sub.att /I.sub.sc).

Abstract: The weight fractions of the phases of a composite material working specimen are determined nondestructively by first performing a sufficient number of nondestructive and destructive calibration measurements on the properties of calibration specimens. The information learned from the calibration specimens is used in combination with nondestructive measurements of the working specimen to determine the fractions of the phases therein, without damaging the working specimen. In one version of this approach, ultrasonic measurements are used to determine fractions of the fiber and matrix in a nonmetallic composite material.

Abstract: In measuring a distribution of crystal grains in metal sheet, an exciting frequency of ultrasonic wave is determined such that a wavelength of the ultrasonic wave propagated in a direction of the sheet thickness of the grains each having an aimed orientation is set at a value of twice the thickness of the sheet multiplied by about integers or about half integers, burst-like ultrasonic pulses having this frequency and including two or more waves are directed into the direction of the sheet thickness by use of an ultrasonic probe moving relatively with a body to be measured, multiple reflected waves generated from the bottom and top faces of the metal sheet upon the reflection from the sheet surface are caused to interfere with each other, the multiple reflected waves, which have interfered with each other, are detected, orientation of the grains in the metal sheet are estimated from the magnitudes in amplitude of the interferent multiple reflected waves thus detected, and the distribution of the grains in orie

Abstract: A method for detecting hydrogen attack by ultrasound wave velocity measurements in which ultrasound waves (e.g. longitudinal, shear, or creeping) are transmitted from one transducer to another transducer along a fixed path through a steel body such as pipe. The velocity of the ultrasound wave is determined with an accuracy of 0.1 percent from the fixed path length and the time for a wave to travel from one transducer to the other transducer. A decrease in velocity by more than two percent indicates hydrogen attack. In one embodiment, either refracted longitudinal or refracted shear waves are transmitted, and the velocities thereof are determined. In another embodiment, a creeping wave is transmitted from one transducer to the other transducer with the creeping wave including a surface wave and a subsurface wave. Travel time of the subsurface wave is measured and used with the known fixed path length in determining velocity.

Abstract: A method is provided for directly measuring the contact pressure on the mating interfaces of two solids undergoing compression where the interfacial region contains an entrapped film of liquid. An acoustic pulse is directed at either interface. A reference amplitude of the acoustic pulse reflected from the interface is measured as it bears initial contact pressure. A second "loaded" amplitude of the acoustic pulse reflected from the interface is measured when the interface is bearing a different contact pressure. A measure indicative of the change in contact pressure is computed from the ratio of the reference and loaded amplitude measurements by correlation with a calibration curve.

Abstract: This invention teaches method and apparatus for determining backscatter attenuation, for utilizing backscatter attenuation to determine the absolute value of quantitative backscatter from a selected point of the body and/or displaying the absolute value of quantitative backscatter in a unique way. More particularly, backscatter from a selected point in the body resulting from a transmitted ultrasonic signal is detected and the quantitative value of the backscatter signal determined. The invention then determines the backscatter attenuation for moving blood at a particular point which is close to the selected point. The determined backscatter attenuation for blood is then utilized to perform an attenuation correction on the detected backscatter signal, thereby providing the absolute value of quantitative backscatter.

Abstract: The dynamic viscosity of a viscous medium is measured by positioning an acoustic transducer in the temperature and pressure environment of the medium and spaced from the medium, then measuring a first resonant frequency and bandwidth for acoustic shear wave propagation within the transducer. The transducer is then positioned in surface contact with the medium, and a second resonant frequency and bandwidth are measured. The viscosity of the medium is calculated from the difference between the first and second resonant frequencies and bandwidths. The step of measuring a first resonant frequency and bandwidth involves applying a first input signal to the transducer to generate acoustic shear waves within the transducer, measuring the frequency and amplitude of the output signal produced by the transducer in response to the acoustic shear waves, and repeating the steps of applying and measuring for a range of first input signal frequencies to determine a first resonant frequency and bandwidth for the transducer.

Abstract: The present invention relates to an ultrasonic examination apparatus which transmits ultrasonic waves into a body to be examined and receives the echo signals therefrom for examination of the inside of the body. The ultrasonic examination apparatus measures acoustic characteristics such as nonlinear parameter within the body using the fact that the characteristic of the reception ultrasonic wave from the inside of the body is varied in accordance with variation of the characteristics within the body. The ultrasonic examination apparatus has first and second ultrasonic transducers for transmitting first ultrasonic pulse and second ultrasonic pulse, respectively. The frequency of the second ultrasonic pulse from the second ultrasonic transducer is higher than that of the first ultrasonic transducer. The first and second ultrasonic pulses are superimposed and transmitted into the body.

Abstract: An ultrasonic image of a living body is obtained by use of an ultrasonic apparatus and, an ultrasound tissue characterization value at a region of interest of the body, such as the ultrasound propagation velocity, the scattered ultrasound waveform width, and the attenuation coefficient, is measured and calculated by use of a cross beam method. These processes are performed in real time and the results of processing are continuously displayed. In this way, the tissue characterization values of the living body can be determined and the state of a disease present in the region of interest can be examined readily and clearly.

Abstract: The invention provides an ultrasonic method of inspecting contents (fluid food, for instance) of a package by disposing an ultrasonic transmitter-receiver system on at least one side of the package and evaluating the occurrence or degree of degradation of the contents on the basis of output data from the system. The invention also provides an ultrasonic apparatus for inspecting contents of a package which comprises a shaking device for feeding and shaking the package, an ultrasonic device disposed independently and downstream of the shaking device, and a guide device for feeding the package downstream of the shaking device to the ultrasonic device and further downstream.

Abstract: Tissue signatures are obtained from first and second order statistics of an image texture to discriminate between different normal tissues and to detect abnormal conditions. These signatures describe intrinsic backscatter properties of the tissue imaged, and are used as the basis of an automatic tissue characterization algorithm. A device for on-line classifying of the texture of an image measures a total of four first and second order statistical properties of echo signals of a region of interest (ROI) selected by an operator, the echo signals being contained in an image memory. These can be used to obtain the tissue signatures, to detect low contrast lesions by machine, and to produce parametric images.

Abstract: It has been observed that attenuation of a transmitted or reflected beam of ultrasound in tissue irradiated with such a beam having a power intensity in the tissue in the non-linear range will change measurably as the tissue temperature changes. Based upon this observation, a method and apparatus for non-invasive thermometry include periodically interrogating the tissue with an ultrasonic beam having a power intensity sufficient such that the power intensity of the beam in the tissue is in the non-linear range. Attenuation coefficients based upon the attenuation of the power intensity of the ultrasonic beam due to the tissue are then periodically determined. Temperature changes in the tissue are determined based upon differences between the determined attenuation coefficients.

Abstract: For determining the charging of a charcoal filter with gases and vapors the acoustical and the electrical impedance of the charcoal layer are measured. The more the filter is charged the greater will be the density of the charcoal layer and therewith its acoustical conductivity. The charging of a charcoal layer with water vapor results in an increase of the acoustical as well as of the electrical conductivity. By comparing the acoustical impedance and the electrical impedance respectively of a partially charged charcoal layer with the impedance of a non-charged charcoal layer and by subsequent comparison of the impedance changes caused by such charging the influence of water vapor can be eliminated. A signal is generated corresponding to the charging of the charcoal filter with other vapors and gases which signal may be used for indicating the condition of the filter and for generating an alarm if the filter becomes exhausted.

Abstract: The weight fractions of the phases of a composite material working specimen are determined nondestructively by first performing a sufficient number of nondestructive and destructive calibration measurements on the properties of calibration specimens. The information learned from the calibration specimens is used in combination with nondestructive measurements of the working specimen to determine the fractions of the phases therein, without damaging the working specimen. In one version of this approach, ultrasonic measurements are used to determine fractions of the fiber and matrix in a nonmetallic composite material.

Abstract: In the apparatus disclosed herein, a bone containing body member to be tested is placed between a pair of transducers and a predetermined sequence of tone signals having frequencies spanning a range from 200 to 600 kilohertz is transmitted through the body member, and the set of values representing the amplitudes of the corresponding received signals are stored. The set of values obtained with the body member between the transducer is normalized using a set of values obtained from the same sequence without the body member in place thereby to generate a third set of values which are compensated for the response characteristics of the transducer and related interfaces. A value corresponding to the rate of change of attenuation with respect to frequency is then calculated from the third set of values and is adjusted for the bone thickness, this adjusted value being related to characteristics of the body member. The bone thickness is determined by a broadband pulse echo measurement.

Abstract: An ultrasonic device in which a concave transducer, partially surrounded by and insulated from a pair of electrically-grounded shields, focuses a signal and directs it to a limited portion of a second lens which further focuses the signal and directs a highly concentrated signal into a fluid, whereby particles therein can be detected with increased sensitivity, and whereby the composition of a homogeneous fluid can be determined by measuring the amount of the attenuation or the sound velocity of ultrasonic pulses therethrough or by comparing the frequency spectrum of the pulse with known spectra.

Abstract: A method and apparatus for measuring the quantity of bubbles in a gas/liquid mixture. An ultrasonic wave is launched into the mixture and the magnitudes of two reflected waves are measured and compared. The logarithm of the magnitudes of the reflected waves is a measure of the quantity of gas content. The method and apparatus are suitable for measuring gas bubble content repetitively in a mixture turbulently flowing through a conduit.

Abstract: The present invention relates to a signal processing apparatus for quantitatively measuring ultrasonic characteristics of a medium, such as a human body and realizes the high speed quantitative measurement by processing all signals in the time domain. In the processing for eliminating an error, produced by a degree of convergence of the ultrasonic beam, a correcting function that is a function of the depth and frequency is employed. The correcting function is measured in a no-attenuation medium and converted into a form suited to the time domain processing. The function is stored and such frequency characteristics of the function are sequentially read during an actual medium measurement to control the characteristic of a variable characteristic filter to correct the received signal.

Abstract: A method and an apparatus for ultrasonically characterizing polymer materials under simulated processing conditions are disclosed. According to the invention, a sample of a polymer is held in confinement between two axially aligned buffer rods having opposed parallel end surfaces spaced from one another to define a gap filled with the polymer sample, the polymer sample being acoustically coupled to the opposed end surfaces of the buffer rods. Ultrasonic waves are transmitted through one of the buffer rods in a direction toward the polymer sample for interaction therewith, and the polymer sample is subjected to controlled temperature or pressure variations over a predetermined period of time, the variation in temperature or pressure being effected via the buffer rods.

Abstract: A first ultrasonic pulse formed by the superposition of a probe pulse on a pump pulse having a frequency lower than the center frequency of the ultrasonic probe pulse where the particle velocity of the pump pulse is in the vicinity of zero in addition to which the particle acceleration of which is at a constant portion, and a second pulse formed by the superposition of the probe pulse center frequency on the peak particle velocity portion of the pump pulse, as well as a probe pulse alone, are transmitted into a specimen before and after it is heated and the reflections of the transmitted signals from two or more reflecting points that are at different depths in the specimen are received. The received signals are subjected to frequency analysis and the spectral shift and the phase shift of the probe pulse and superposed pulses are obtained, and from these values the attenuation of the probe pulse between the differing depths is determined.

Abstract: A biological or other material is scanned along a line or plurality of lines by at least one transducer, and the signals received are separated into n substantially equal, consecutive frequency bands after which the envelope of the signals in each frequency band is determined. Each of the signal envelopes, being proportional to the power spectrum of the echographic signal, is divided by a dividing signal which is proportional to the power spectrum of a phantom which has the same attenuation as the object being examined, the logarithm being determined of the signal resulting from this division, after which the following operations are performed in the channels a, b, . . . , i, . . .

Abstract: An ultrasonic nondestructive system and method for monitoring resin cure during composite sheet material fabrication is described which comprises a first transducer for directing a plurality of ultrasonic pulses of preselected pulse frequency along a selected propagation axis onto a first surface of the material during the curing of the resin, a second transducer near the second surface of the material for receiving transmitted pulses and for providing output signals characteristic of the transmitted pulses, and electronic signal processor and display equipment responsive to signals from the second transducer for analyzing the signals and providing output corresponding to the amplitude and duration of the transmitted pulses.

Abstract: An apparatus and method for detecting the presence of liquid in pipes or tubes using ultrasonic techniques A first piezoelectric crystal is coupled to the outside of the pipe or tube at the location where liquid in the tube is to be detected. A second piezoelectric crystal is coupled to the outside of the pipe or tube at the same location along the tube but circumferentially displaced from the first crystal by an angle around the pipe or tube of less than 180.degree.. Liquid in the pipe or tube is detected by measuring the attenuation of an ultrasonic signal sent by the first piezoelectric crystal and received by the second piezoelectric crystal.

Abstract: Ultrasonic waves of at least three independent frequency bands having different center frequencies are transmitted into a living body from its skin surface and reflected waves are analyzed, by which living tissue characteristics are measured. The reflected waves from various depths in the living body are received, their frequency components are separately extracted and energies of the received reflected waves are obtained, thereby obtaining an attenuation coefficient inclination and a space inclination of a frequency power exponent of a reflection coefficient of the living body.