Abstract: The present invention provides an ultrasonic method for measuring the size of a possible flaw in a solid mass, in which an ultrasound is transmitted perpendicularly to the searching surface of a solid mass being the object under measurement through a liquid, a ratio in sound pressure between a reflected wave of the ultrasound from the surface of the solid mass and a reflected wave from any flaw in the solid, and a distance from the surface of the solid mass to the flaw, derived from the difference in time of reception between the reflected wave from the surface of the solid mass and the reflected wave from the flaw in the solid mass, are taken as indices of evaluation, and these indices of evaluation are compared with a reference value obtained beforehand by measuring a test piece made of a same material as that of the solid mass, thereby determining the size of the flaw.

Abstract: A method for measuring texture of metal plates or sheets using non-destructive ultrasonic investigation includes measuring the velocity of ultrasonic energy waves in lower order plate modes in one or more directions, and measuring phase velocity dispersion of higher order modes of the plate or sheet if needed. Texture or preferred grain orientation can be derived from these measurements with improved reliability and accuracy. The method can be utilized in production on moving metal plate or sheet.

Abstract: Method and apparatus for detecting cracks in a shaft by means of an ultrasound pulse echo method. A test hand having an ancillary wedge is coupled to the end face of the shaft for conducting nondestructive testing of the shaft. The test head emits ultrasound pulses of a determined frequency and is moved by means of a mechanical device in front of the end face. The method makes possible reliable and reproducible detection of cracks present at the circumference of long shafts. The test head delivers sound pulses in the range of 4 to 8 MHz and is placed by means of the device at a radial distance from the shaft end face's central axis. The test head is moved in the course of the measurements in three degrees of freedom; along a radius of the shaft, along a circle of the shaft and about the axis of the test head holder. The method and apparatus are employed for testing long turbine shafts in the assembled condition from the end face on the generator side of the shaft.

Abstract: A Magnetic Resonance (MR) data acquisition system using driven equilibrium in a spin echo scan sequence wherein the dephased spins in the transverse plane are accurately refocused prior to being driven to the Z axis and the encoding gradient pulses are distributed and adjusted to keep the encoding gradient pulses from affecting the refocused magnetization.

Abstract: A magnetic resonance imaging apparatus has a first surface coil for detecting a magnetic resonance signal induced in an object under examination. An induction current flows through the first surface coil by the magnetic resonance signal. A second surface coil is arranged to oppose the first surface coil through the object to be examined. The second surface coil is electrically endless. Therefore, a magnetic field is generated by the induction current. The magnetic field changes in accordance with a change in magnetic resonance signal. An eddy current flows through the second surface coil without flowing through the object to be examined in order to interfere with a change in magnetic field. As a result, an eddy current can be prevented from flowing through the object to be examined.

Abstract: A nonsynchronous turbine blade vibration monitoring system is comprised of a maximum of two sensors circumferentially mounted along the turbine blade row for detecting the actual arrival times of the turbine blades at the sensors. Expected arrival times of the turbine blades at the sensors are determined and then compared to the actual arrival times in order to obtain turbine blade deflection data. Harmonic analysis is then performed on the blade deflection data to determine the level of vibration at each non-integral harmonic.

Abstract: A RF volume coil with optimized signal-to-noise ratio, for NMR use, has a reduced length L.sub.c, which is between about 0.3r.sub.s and about 1.5r.sub.s, where r.sub.s is the radius of a sample-to-be-investigated, contained within the cylindrical volume coil, with the volume coil radius r.sub.c being between about 1.0r.sub.s and about 1.6r.sub.s. the "short" volume coil has an improved SNR for a voxel located substantially on the central plane of the coil, relative to the SNR of a "normal"-lenth volume coil with L.sub.c .gtoreq.4r.sub.s.

Abstract: A multi-point wall thickness gage (10) comprises a pad (16) of flexible magnetic material that includes an array of ultrasonic transducers (13) and a multi-point ultrasonic transmitter and receiver (25) to which each transducer (13) is attached. The magnetic pad (16) is attachable to the wall of a ferro-magnetic object (19), and serves to hold the array or matrix of ultrasonic transducers (13) against the wall of the object. The specific region of the object wall being inspected is marked off (17), and the magnetic pad (16) is periodically applied over this region (17). The output of the transducers (13) is used to detect whether any wall thinning is occurring over the particular area of the object covered by the magnetic pad (16), and if so, the particular pattern of thinning within the area. Trend monitoring is simplified since exact relocation of the transducers (13) for periodic measurements is more readily accomplished.

Abstract: An array of plural magnetic resonance imaging (MRI) RF coils is provided having different and overlapping fields of view. Controllable switches are connected with each individual coil of the array and are capable of selectively conditioning any one of the coils for individual usage in an MRI procedure. Either mechanical or electrical (e.g., PIN diode) switching control may be utilized. Preferably, controllable electrical switches are located at points having approximately zero RF potential. Distributed capacitance is also preferably employed for reducing terminal inductance, preventing the establishment of spurious magnetic fields and facilitating the use of electrical switching diodes and/or varactor capacitance elements. Such distributed capacitances are also dimensioned so as to cause the terminal inductance of each coil to be within the tuning/matching range of a common tuning/matching RF circuit.

Abstract: A multi-echo magnetic resonance imaging sequence is implemented such that a radio frequency receiver (34) receives magnetic resonance signals during each of a plurality of magnetic resonance echoes. The resonance data received during each echo are digitized and the resultant echo data are stored in a corresponding echo memory (40, 42). The locations of the data within the memories are brought into registration (52) such that corresponding data in each memory is disposed at the same memory address. Because data from later echoes tends to be weaker or at a lower magnitude, the magnitude of the data stored in each memory is normalized (60). The phase of the data in each memory is brought into coordination by a zero order phase correction (70). A high pass filter (84) and a complementary low pass filter (86) separate complementary portions of the data from the memories. The separated portions are combined into a single synthesizied data set for storage in memory (82).

Abstract: A light beam altering grid (20), having a graded slit density pattern (22), is mounted on a temperature responsive support structure (23) to traverse a light beam (28). The slit density (slit per unit length) of the grid (20) is greater at one end of the grid (20) and gradually reduces towards the opposite end of the grid (20). The grid (20) is disposed on a thermally responsive support (23) such as a bimetallic cantilever (23). The thermally responsive support (23) operates to bend by an amount dependent upon the temperature of the environment in which it operates. In this manner, the grid (20) disposed on the thermally responsive support (23) is positioned in dependence upon the environmental temperature.

Abstract: A magnetic resonance apparatus comprises a main probe coil adapted for transmission and reception of a high frequency to and from a large region of an object under examination or for transmission of the high frequency to the object, a local probe coil formed of a surface coil adapted for transmission and reception of a high frequency to and from a local region corresponding to a local portion of the object or for reception of the high frequency, and a main gradient coil adapted for application of a gradient magnetic field to a large region of the object. The local probe coil is used for measurement of the local region. The magnetic resonance apparatus is further provided with a relatively small-sized local gradient coil for producing a local gradient magnetic field in the sensitive region of the local probe coil and its vicinities only.

Abstract: In a scanning acoustic microscope of the reflection type, in which an object is insonified with a series of ultrasonic acoustic pulses in accordance with a preselected scanning pattern and reflected acoustic echo pulses are received and employed to generate an initial electrical signal comprising a sequence of electrical pulses having amplitudes and polarities representative of the magnitudes and phases of the echoes, a directly readable unified interpretative display image is produced from the entire electrical signal; that image includes the usual scanning position and depth information determined by timing of the electrical pulses, together with complete transition information regarding the nature of acoustic impedance changes, based on both the amplitudes and the polarities of those pulses. A compared dual integration method and system, with related gating and display enhancement techniques, comprises the preferred embodiment.

Abstract: An ultrasonic scanning system utilizing a selectively rotatable reflector permitting selective use of multiple transducers mounted around the periphery of a water jet for flaw detection in composite materials.

Abstract: Seizable, connection-associated switching devices of various types emit processing requests with different urgency degrees to a central sequential logic system for information which are to be processed with different urgency dependent on type. A limit value which may be set in an occupation rejection device based on the measure of a continuously-measured, momentary sequential logic system load serves as a comparison normal and effects that processing requests are rejected (accepted) when the urgency value is lower than (greater than) the limit value.

Abstract: An apparatus and method for achieving variable observation angles by a single transducer rotationally and pivotally mounted with a housing; and for utilizing the variable angle transducer to detect and trace the distance of unseen objects within a casing from the transducer by moving the transducer within its housing which is held stationary against the casing; and for determining the angle of observation between the transducer and the observed object; and thereby accurately determining the relative position and orientation of the object within the casing.

Abstract: A method for continuously measuring the stiffness and area of contact between two bodies is provided. Elastic stiffness of a junction is measured by introducing a relatively small oscillatory mechanical force at a known frequency to the junction and measuring the subsequent displacement response using AC signal-handling techniques to provide a continuous measurement proportional to the stiffness and the area of contact between the bodies, even as the area of contact changes.

Abstract: An ultrasonic inspection probe for locating and sizing flaws in the radius region (20) and adjacent areas of a laminated structure (10), such as a composite "T" stiffener (30). The probe includes a plurality of shoes (48, 50, 52, 54, 56, 58) that are arranged for coordinated movement relative to the part under inspection. Each shoe includes a plurality of ultrasonic transducers that are arranged in predetermined adjacent relationships to one another and operated in timed sequence in one or more through-transmission, pulse echo or loss-of-back modes to effect an ultrasonic scan in one direction through the part while the transducers are moved together in another direction along the part. Inspection of the radius region is effected using combinations of angular pulse echo inspection (PEF, PEA, LL45P, RL45P), "radius-to-radius" through-transmission inspection at an angle through the radius region (RTT, RTR, L37.5T, L37.5R, U37.5T, U37.

Abstract: A method and an apparatus for determining at least one moment acting about a predetermined axis of an object placed on a force measuring apparatus in a flowing medium. In order to compensate measurement errors caused by a displacement of the center of gravity of the object upon application of the flowing medium exactly defined variable forces are applied to the object prior to the application of the flowing medium. The displacement of the center of gravity of the object is determined in dependence on the force variation and then taken into consideration when evaluating the force and moment measurements.

Abstract: A device and method are provided for adjusting a radiofrequency antenna of a nuclear magnetic resonance apparatus. In the invention, using capacities preset in the factory, the antenna detuning of an NMR apparatus is limited to a range such that the standing wave rate of a high frequency line which conveys the radiofrequency signal is limited. This line is cut and, at a short distance, a tuning adjustment circuit is inserted. This circuit may be automated: the electric adjustment motors, thus spaced away, do not disturb the magnetic fields of the apparatus. By measuring the real part of the admittance at the input of the adjustment circuit and the phase shift between voltage and current this circuit can be adjusted.