Abstract: The present invention relates to a method and a device for monitoring a flowing medium, in particular the blood flowing in an extracorporeal blood circulation, for the presence of air, in particular micro-bubbles. A sequence of signal pulses or a continuous signal is injected into the flowing medium, and the signal pulses or continuous signal leaving the flowing medium are received. To detect micro-bubbles, a signal pattern that is characteristic of the variation over time of the received signal pulses or the continuous signal in a predetermined period of time is extracted from the signal received. The characteristic signal pattern is compared with one or more characteristic reference patterns, and the presence of air bubbles is determined if the characteristic signal pattern deviates from the characteristic reference pattern by a predetermined amount. Statistical characteristic variables, in particular the variance, are preferably determined from the signal patterns and compared with one another.

Abstract: A method for inspection of tubular goods includes using ultrasonic detection means to obtain wall thickness measurement of discrete sections of a tubular good and recording each measurement in association with both the longitudinal and circumferential position at which each measurement was obtained. Accordingly each measurement of wall thickness represents a small portion of the wall thickness of said tubular in three dimensional space. A plurality of said measurements may thereby be displayed by computer means in virtual three dimensional format. Differing wall thickness readings made be represented by different shading or color display, so that anomalies of interest may be readily detected. Alternatively the recorded information may be readily processed by computer means to calculate the effect of stressors on the wall of said tubular good.

Abstract: A method and apparatus for determining the performance level, amount of wear, and remaining useful life of a new or worn object, preferably of metallic construction through harmonic fatigue evaluation. The object to be tested is struck with a resonant frequency generating device, causing the object to transmit its vibrational resonance to at least one signal receiving transducer. The transducer then relays the frequency back to a database wherein it is compared to known frequency responses of that specific object through a linear continuum from prior controlled testing, to determine the remaining performance level in comparison to a new object of the same construction.

Abstract: A system and method for inspecting a structure having a coating on at least one surface are provided. The system includes at least one ultrasonic sensor positioned proximate to the structure. Each sensor is capable of transmitting a shear wave toward the structure and receiving return signals in response thereto, wherein the shear wave includes at least one reference beam and at least one interrogating beam. The system further includes a data acquisition system in communication with the sensor for generating information indicative of the coating based on at least one return signal associated with the reference beam.

Abstract: A digital pulsed phase locked loop (DPPLL) provides exact measurements of echo phase, time, and/or position delay as well as echo amplitude. These exact measurements provide better and more reliable results that directly benefit the many real world applications for the DPPLL. The DPPLL permits simultaneous tracking of multiple echo pulses and considerably improved echo selection and sampling.

Abstract: Methods and apparatus for detecting particles flowing in a fluid within a conduit involve analysis of acoustic pressure signals detected with an array of at least two pressure sensors. The analysis can include monitoring for attenuation in power of the acoustic disturbances within the fluid and/or a reduction in a speed of sound in the fluid. This attenuation in power or reduction in the speed of sound can be detected to provide an output or otherwise indicate that particles are present in the fluid.

Abstract: A computer implemented method, or hardware filtration apparatus, and computer usable program code for measuring porosity in materials. An ultrasonic signal is emitted from a transmitting transducer in an ultrasonic measurement system into a material. A response signal is received at a receiving transducer in the ultrasonic measurement system from the material. The response signal is filtered to pass only frequencies in the response signal within a selected frequency range to form a filtered response signal. A porosity level of the material is identified using the filtered response signal.

Abstract: The invention is directed to a system and method for detecting defects in a manufactured object. These defects may include flaws, delaminations, voids, fractures, fissures, or cracks, among others. The system utilizes an ultrasound measurement system, a signal analyzer and an expected result. The signal analyzer compares the signal from the measurement system to the expected result. The analysis may detect a defect or measure an attribute of the manufactured object. Further, the analysis may be displayed or represented. In addition, the expected result may be generated from a model such as a wave propagation model. One embodiment of the invention is a laser ultrasound detection system in which a laser is used to generate an ultrasonic signal. The signal analyzer compares the measured ultrasonic signal to an expected result. This expected result is generated from a wave propagation model. The analysis is then displayed on a monitor.

Abstract: An ice thickness measurement system for determining thicknesses of an ice sheet such as an ice rink that is positioned on a solid or granular substrate. The system determines the thickness of the ice sheet using an acoustic technique, is portable, and may include a display graphic or graphical user interface on the portable unit to direct operators of the unit where to conduct an array of measurements on the ice sheet. The system may also be compatible with a computer for downloading of data and uploading of graphical displays.

Abstract: A sensor system for determining the position of at least two edges of at least one web material traveling along a predetermined path. In one embodiment, the sensor system has at least one transmitter block having a plurality of transmitters capable of selectively transmitting ultrasonic signals and at least one receiver block having a plurality of receivers capable of generating receiver output signals in response to the receivers receiving at least a portion of the ultrasonic signals transmitted by the at least one transmitter block. The receiver block is spaced a distance from the transmitter block so as to define a continuous sensor field of view therebetween whereby at least a portion of the at least one web material traveling along a predetermined travel path interferes with at least a portion of the ultrasonic signals transmitted by the at least one transmitter block.

Abstract: The invention relates to a method and a device for monitoring a flow of liquid for the presence of air bubbles, in particular the blood flowing in an extracorporeal blood circuit of an extracorporeal blood treatment device. The air bubbles are detected by an ultrasound measurement and the ultrasound signals received in a continuous sequence of time intervals are each compared to a predetermined reference level. When the amplitude of the ultrasound signal, or a parameter correlating to the amplitude of the ultrasound signal, is less than the predetermined reference level, the presence of a defined volume of air is determined. When the number of times the ultrasound signal is less that the predetermined reference value if is greater than the set limit value, it is determined that a critical volume of air is present in the patient's blood and the dialysis is stopped.

Abstract: A biosensor detection system for detecting a particular substance has at least two biosensor devices. Each biosensor device includes a piezoelectric material, an input transducer mounted on the piezoelectric material to receive an input radio frequency signal and propagate a corresponding acoustic wave within the piezoelectric material and an output transducer mounted on the piezoelectric material to receive the acoustic wave and transmit a corresponding output radio frequency signal. A biolayer is mounted on the piezoelectric material to receive a substance to be tested and cause a corresponding change in the acoustic wave. An oscillator circuit is connected to the input transducer and to the output transducer, the oscillator circuit including an amplifier and providing an output signal indicative of a change in the acoustic wave.

Abstract: A method for measuring a first angular specific sound absorption spectrum of a first sound absorbing sample. The first sound absorbing sample has a predetermined random incidence sound absorption spectrum. The angular specific sound absorption spectrum is determined from a sound wave incident on a surface of the first sound absorbing sample with a predetermined angle of incidence that is greater than zero degrees from a plane parallel to the surface of the first surface. A first weighting factor that provides a fit of the angle specific sound absorption spectrum of the first sound absorbing sample to the predetermined random sound absorption spectrum is then determined. Next, a second angular specific sound absorption spectrum of a second sound absorbing sample at the predetermined angle of incidence is determined. The weighting factor is then used to determine the random specific sound absorption spectrum from the angle absorption spectrum of the second sound absorbing sample.

Abstract: A liquid dispensing apparatus for dispensing droplets of a liquid, and methods for measuring various fluid parameters of the liquid are described. The liquid dispensing apparatus comprises a container having a chamber for holding a liquid. An orifice is positioned at an end of the chamber for dispensing droplets of the liquid, the orifice being configured to retain the liquid in the container if the container is positioned with the orifice facing in a downward direction. An acoustic transducer means is at least partially positioned in the chamber for periodically propagating a focused acoustic beam toward the orifice and through at least some of the liquid while the liquid is contained in the chamber, with the focused acoustic beam being capable of causing a droplet of the liquid to be ejected from the orifice when a free surface of the liquid is within the depth of field of the acoustic transducer means.

Abstract: A method and apparatus for conducting ultrasonic inspections of what would normally be inaccessible areas of objects for such properties as thickness, cracks, discontinuities, density, pits and holes. In addition, a method and apparatus for improving ultrasonic inspections with a method for removing trapped gasses from the couplant. Also, a method and apparatus for conduction ultrasonic inspections of objects for multiple properties such as thickness, cracks, discontinuities density, pits and holes with at the same time with a single transducer. Further more, a method and apparatus for conducting rapid ultrasonic inspections of concave surfaces of objects for multiple properties such as thickness, cracks, discontinuities density, pits and holes with a single transducer. This invention allows for the inspection of the entire surface of the object or specific defined areas.

Abstract: A sensor system for determining the position of at least one edge of at least one web material traveling along a predetermined path. In one embodiment, the sensor system has at least one transmitter block having a plurality of transmitters capable of selectively transmitting ultrasonic signals and at least one receiver block having a plurality of receivers capable of generating receiver output signals in response to the receivers receiving at least a portion of the ultrasonic signals transmitted by the at least one transmitter block. The receiver block is spaced a distance from the transmitter block so as to define a sensor field of view therebetween whereby at least a portion of the at least one web material traveling along a predetermined travel path interferes with at least a portion of the ultrasonic signals transmitted by the at least one transmitter block.

Abstract: A method for inspection of tubular goods includes using ultrasonic detection means to obtain wall thickness measurement of discrete sections of a tubular good and recording each measurement in association with both the longitudinal and circumferential position at which each measurement was obtained. Accordingly each measurement of wall thickness represents a small portion of the wall thickness of said tubular in three dimensional space. A plurality of said measurements may thereby be displayed by computer means in virtual three dimensional format. Differing wall thickness readings made be represented by different shading or color display, so that anomalies of interest may be readily detected. Alternatively the recorded information may be readily processed by computer means to calculate the effect of stressors on the wall of said tubular good.

Abstract: A measuring method using a surface acoustic wave device, with which even in a case where a target substance having a different viscosity is added to a buffer liquid on the surface acoustic wave device it is possible to measure a mass load accurately without suffering an effect of this viscous load, and it is also possible to shorten the time taken for the temperature of the buffer liquid to stabilize and thereby shorten the time taken for the measurement.

Abstract: Ultrasonic measurements of porosity in manufactured parts or materials are calibrated using reference standards in which parallel holes are drilled in the backside of a body of material. The holes simulate voids in a part which attenuate incident ultrasonic energy. The number, size and location of the holes determine the simulated level of porosity that may be used to calibrate an ultrasonic tester. Multiple reference standards representing different levels of porosity can be produced in the form of individual coupons, or in a single body having multiple groups of holes.

Abstract: The lateral position of a web or fabric edge 11 in a paper machine is determined using an ultrasonic sensor. The ultrasonic sensor has a detector head 42, with an air channel system which opens to the vicinity of the head for forming an air knife which prevents accumulation of dirt on the head. The protective cover 35 has an air guide 43 extending further than the detector head 42, with air flowing thereabove from inside the protective cover 35 through an opening 36. The end component is on top of the protective cover allowing air to flow from the opening between the air guide and the end component to a detent, which turns the direction of the air flow. This provides efficient cleaning without disturbing, however, the operation of the ultrasonic sensor.

Abstract: A method for non-destructively inspecting a composite structure with a single ultrasonic transducer includes determining a calibration amplitude of ultrasonic transmissions emitted by the single ultrasonic transducer to a reflector in a fluid-filled immersion tank and received back at the single ultrasonic transducer. The method also includes inserting the composite structure into the fluid-filled immersion tank between the reflector and the single ultrasonic transducer. In addition, the method includes scanning the composite structure with the single ultrasonic transducer to measure ultrasonic amplitudes for sound waves traveling through the composite structure, reflecting off the reflector plate and then traveling back through the structure to the single ultrasonic transducer.

Abstract: An RFID biosensor detection system for detecting particular substances has an interrogator circuit to transmit a radio frequency signal, an input transducer mounted on a piezoelectric material to receive an input radio frequency signal and propagate a corresponding acoustic wave within the piezoelectric material. At least two chemically orthogonal or semi-orthogonal biolayers are mounted on the piezoelectric material to receive substances to be tested and cause corresponding changes in the acoustic wave. An output transducer is mounted on the piezoelectric material to receive the acoustic wave and transmit a corresponding output radio frequency signal. A receiver circuit receives the corresponding output radio frequency signal and provides separate channel data indicative of the substances received.

Abstract: A sensor system for determining the position of at least one edge of at least one web material traveling along a predetermined path. In one embodiment, the sensor system has at least one transmitter block having a plurality of transmitters capable of selectively transmitting ultrasonic signals and at least one receiver block having a plurality of receivers capable of generating receiver output signals in response to the receivers receiving at least a portion of the ultrasonic signals transmitted by the at least one transmitter block. The receiver block is spaced a distance from the transmitter block so as to define a sensor field of view therebetween whereby at least a portion of the at least one web material traveling along a predetermined travel path interferes with at least a portion of the ultrasonic signals transmitted by the at least one transmitter block.

Abstract: A method and system is disclosed for determining a property of an object by measuring ultrasonic attenuation. With the proposed method, a measured ultrasonic interaction signal of the object is compared with a reference signal produced using the same generation and detection setup, but using a reference part. The reference ultrasonic signal has low attenuation, and exhibits equivalent diffraction properties as the object, with respect to a broadband ultrasonic pulse. The difference is attributable to the attenuation of the object. The attenuation as a function of frequency, the attenuation spectrum, is fitted to a model to obtain a parameter useful for identifying one of the many properties of an object that varies with ultrasonic attenuation.

Abstract: This invention discloses a method of evaluating the internal structure of a grinding wheel through ultrasonic inspection.

Abstract: The state or condition of a data storage drive, or a subsystem within a drive, may be evaluated by comparing a set of selected parameter values, converted into a trial vector, with a number of model or exemplar vectors, each of which was represents a particular state or condition of a sample drive. Examples of such conditions may include “good”, “marginal”, “unacceptable”, “worn”, “defective”, or other general or specific conditions. Sets of parameter values from the drive are converted into input vectors. Unprocessed vectors are then processed against the input vectors in an artificial neural network to generate the exemplar vectors. The exemplar vectors are stored in a memory of an operational drive. During operation of the drive, the trial vector is compared with the exemplar vectors. The exemplar vector which is closest to the trial vector represents a state which most closely represents the current state of the drive.

Abstract: The present invention provides a device and method of non-destructively monitoring reactive material through a substrate for changes in material properties that designate the condition of the reactive material during cure and service life. A transducer is placed on a portion of the substrate generally parallel to an interface of the substrate to the reactive material. The ultrasonic waves generated via the transducer are used to detect reflected sound waves upon encountering the interfaces, where the interfaces consist of changes in material properties across the substrate.

Abstract: A method and apparatus for estimating a depth of a crack from ultrasound scan data are provided. The method includes mapping multiple amplitude responses from the ultrasound scan data, each mapped amplitude response being representative of a signal from one of the sensors. The method further includes locating multiple linear responses among the mapped amplitude responses, each linear response being an indicator of a reflected signal from the crack. One or more sensor that corresponds to the linear responses from a given crack is identified. The depth of the crack is estimated using data from the identified sensors.

Abstract: A human or other status discriminating apparatus includes an ultrasonic vibration detecting sensor comprising a container main body, a liquid packed tightly in the container main body, and an ultrasonic vibrator for transmitting ultrasonic waves into the liquid and receiving ultrasonic waves reflected from the liquid surface, to detect behavior of a subject, an ultrasonic transmission and reception control device including an ultrasonic transmitter/receiver, a signal converter, and a microcomputer, for issuing a transmission signal at specific time intervals to the ultrasonic detecting sensor, receiving a reception signal at specific time intervals from the ultrasonic detecting sensor, and calculating risk associated with the detection object from the change of maximum amplitude of the input reception signal, and a cable for coupling the ultrasonic detecting sensor and ultrasonic transmission and reception control device, and forming an input and output passage of transmission signal and reception signal.

Abstract: Hand-held apparatus and method for determining relative and/or absolute axial position of a conduit end within a fluid coupling includes application of input ultrasonic energy in the form of transient shear waves and analyzing the reflected energy. Application of the input energy collected at different radial positions about a first axial location is used with wavelet based correlation techniques to better analyze the reflected energy signals. Quality of the abutment between the conduit end and a surface associated with the coupling may also be determined as a separate or combined feature of the axial position determination.

Abstract: A method of testing a material sample for defects, comprising the steps of applying a test signal to the material sample, receiving a return signal from the material sample and analysing the return signal to determine whether the material sample is defective. In one aspect of the present invention the steps of receiving a return signal and analysing it include the step of selecting a frequency range to reduce the effect of potentially interfering signals. In another aspect of the present invention a reference signal obtained from a non-defective sample is subtracted from the return signal to give a difference result and the difference result is indicative of whether the material sample is defective. Apparatus for carrying out the above-defined methods are also provided.

Abstract: A tuning device (23) and an apparatus that incorporates the tuning device (23) for use in testing the integrity of a railway line (30) to obtain an improved test signal, the tuning device (23) including an elongate member (23) adapted to be attachable at one end of the railway line (30) being tested in situ or is attachable to an attachment member (21) coupled to the section (10) of railway line (30), and wherein a vibration signal measuring means (24) is adapted to be secured to the other end of the elongate member (23).

Abstract: A method for inspection of tubular goods includes using ultrasonic detection means to obtain wall thickness measurement of discrete sections of a tubular good and recording each measurement in association with both the longitudinal and circumferential position at which each measurement was obtained. Accordingly each measurement of wall thickness represents a small portion of the wall thickness of said tubular in three dimensional space. A plurality of said measurements may thereby be displayed by computer means in virtual three dimensional formal. Differing wall thickness readings made he represented by different shading or color display, so that anomalies of interest may be readily detected. Alternatively the recorded information may be readily processed by computer means to calculate the effect of stressors on the wall of said tubular good.

Abstract: The invention relates to a method for determining the size of a fracture (26) in a workpiece (20), in particular the depth of a fracture (26) in said workpiece (20), by means of the ultrasound pulse method, comprising the following method steps: a workpiece (20), with a front surface (22) and a back surface (24), having a fracture (26), extending from the back surface (24) and an angle test head (28) is applied to the front face (22), transmits ultrasound pulses at an angle alpha into the workpiece (20) and receives echoes from said pulse, the angle test head (28) is moved at least once over the fracture (26), such that the radiation beam (46) from the angle test head (28) completely covers the fracture (26), the received echo signals are digitized and stored in a memory (40) as variable pairs of echo signal versus runtime, the variable pairs form a value upwardly defined by an envelope (48) and the dimension of the fracture (26) is determined from the width of the envelope (48) at a given partial amplitude a

Abstract: An inspection method can easily determine welding condition by just comparing an echo height returned from the weld zone of a real product with a master data. An master data is made based on the data from prepared test pieces corresponding to the real product.

Abstract: A chemical mechanical polishing apparatus and method can use an eddy current monitoring system and an optical monitoring system. Signals from the monitoring systems can be combined on an output line and extracted by a computer. A thickness of a polishing pad can be calculated. The eddy current monitoring system and optical monitoring system can measure substantially the same location on the substrate.

Abstract: Method for determining the composition of a homogeneous fluid, for example a petroleum effluent on flow, an emulsion consisting of water and oil, or a foam consisting of oil and gas. The attenuation and the phase shift of microwave beams that have traversed a fluid of unknown composition with paths of different lengths are measured (stage A). Two equations approaching the measured values are determined, the first equation giving a relation between the attenuation and the length of the path, the second equation giving a relation between the phase shift and the length of the path (stage C). Then the composition of the fluid is determined by comparing the two equations with pairs of equations stored in form of databases, each pair of equations corresponding to a fluid of known composition (stage D).

Abstract: A method for determining vibration amplitude limits of a mechanical device. The method comprises identifying a mechanical device and a frequency range for a spectrum to be analyzed, retrieving vibration spectra comprising individual spectrum for the mechanical device and the frequency range, calculating frequency for the individual spectrum, and identifying the individual spectrum with the smallest number of frequency lines. In addition, the method comprises calculating noise bandwidths and a largest noise bandwidth, removing outlier data, calculating conditional kernel density, and calculating vibration amplitude limits to detect faults in the mechanical device.

Abstract: A fermention process is monitored by detecting ultrasound backscattered from the cells as a function of time. A transducer 46 is placed in a fermentor 30 and transmits ultrasound towards a reflecting surface 50. The transducer receives that portion of the ultrasound which reflects from the reflecting surface 50, as well as that portion of the ultrasound which backscatters from cells 34 between the transducer 46 and the reflecting surface 50. Signals from the transducer are conditioned and subsequently processed to provide output to a controller regarding the status of the fermentation process in real time. The backscattering measurements can be used to determine a growth phase transition, such as the transition between the logarithmic growth phase of the cells and their stationary phase.

Abstract: A system to perform measurements on liquids, meat, viscous sugar or starch-based materials, and other foodstuffs using air-coupled ultrasound is provided. The technique uses ultrasonic transducers (advantageously capacitive transducers with polymer membranes), to generate ultrasonic signals in air, and to receive these signals after they have passed through the material under test. An ultrasonic pulse-compression process is then applied to increase the sensitivity of signals transmitted through the materials.

Abstract: A method and system for determining the fiber volume fraction of a composite structure. The system includes a unit for ultrasonically determining the porosity volume fraction in the article, and a unit for calculating the volume fraction of the fibrous reinforcement material in the article based on the porosity volume fraction in the article and the mass densities of the article and the fiber and matrix materials within the article. The method entails determining the mass density of the article, obtaining the mass densities of the fiber material and the matrix material, ultrasonically determining the porosity volume fraction in the article, and then calculating the volume fraction of the fibrous reinforcement material in the article based on the porosity volume fraction in the article, the mass density of the article, the mass density of the matrix material, and the mass density of the fiber material.

Abstract: A method and apparatus for detecting and automatically identifying defects in technical equipment, is disclosed. Measurement signals varying in time are downloaded as spectrograms to a computer memory. Using a predetermined criteria a set of designated peak values is created. Using another predetermined criteria the set of designated peak values is divided into two subsets. Then in one of the subsets, peak groups differing from each other by the basic frequency values are distinguished. The second subset, created from the set of designated peak values, is searched for the presence of sidebands for peaks from each specified peak group and if the sidebands are present the basic frequency of the sidebands is calculated. Then the existence of a defect in the technical equipment is detected, and identified by comparing the basic frequencies and the basic frequencies of the sidebands with the frequency values collected in the computer memory.

Abstract: A method and apparatus for determining the composition of a containerized material, typically a suspension, through which ultrasonic waves are passed. The component ratios and particle sizes of a stationary or flowing material are determined by measuring ultrasonic wave phase and attenuation changes at multiple frequencies and deriving shape features from curves of the phase or attenuation versus frequency. Preferably, the frequency range employed extends below and above the frequency of maximum attenuation of the expected mean particle size in a suspension. The material composition is derived from analysis of the shape features of the derived curves.

Abstract: A welding system includes a device for evaluating an ultrasonic signal during a welding process. The device has a meassured value evaluation unit that, in normal operation, evaluates at least one measurement signal that is derived from an ultrasonic signal and is located inside a measurement window. A mechanism for establishing the measurement window is provided, which establishes the measurement window according to a measurement signal that is received in a calibration operation.

Abstract: A device for the free-jet ultrasonic testing of a workpiece by the transmission technique includes a first test head, serving as an ultrasound transmitter, and a second test head, serving as an ultrasound receiver. The test heads are respectively disposed on a first robot and a second robot, in each case in a freely movable manner, with at least one degree of freedom, such that they are aligned coaxially in relation to each other and perpendicular to a surface of a workpiece. The robots are positioned such that they are fixed in place on a displaceable common carrier.

Abstract: An ultrasonic pulse/echo measurement arrangement includes an ultrasonic transducer (12), which is mounted spatially fixed on an air spring cover plate (4). The arrangement further includes a fixedly mounted reference reflector (14), a target reflector (16) mounted on a roll-off piston (8) or on the bumper (18) as well as a transmitter/receiver evaluation electronic circuit (30). The running time as well as the amplitude of the reference signal is evaluated to precisely determine the pressure present in the interior space of the air spring. The ultrasonic transducer (12) has a ?/4-adaptation layer (22), whose impedance does not correspond to the geometric mean of the impedances of the ultrasonic transducer (12) and the ambient air of the interior space (20) of the air spring, but rather, is a mismatch. The evaluation electronic circuit (30) can be calibrated at ambient pressure for the determination of the inner pressure of the air spring.

Abstract: A method of ultrasound inspection is provided. The method includes providing a composite first part, introducing ultrasound to the part, receiving reflections of the ultrasound introduced in the first part, and predicting a residual strength of the first part using an amplitude of the received reflections.

Abstract: A source of ultrasound waves or energy is directed at the wafer that is to be inspected in a direction that is essentially perpendicular with the surface of the wafer. The ultrasonic waves are intercepted and analyzed after these waves have passed through the wafer that is being inspected. From this analysis and comparing the captured waves or ultrasonic energy with the emitted ultrasonic waves, conclusions can be drawn on defects and other irregularities that are present in the medium, that is the wafer, through which the ultrasonic waves have passed.

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 method to determine a depth of an internal feature in a forging using an ultrasonic transducer including: collecting data on echoes reflected by the internal feature of ultrasonic signals transmitted into the forging; correcting the collected data to compensate for attenuation of the echoes and signals in the forging, and determining a depth of the internal feature in the forging.