Abstract: A nuclear magnetic resonance image used for detecting the internal state of a substance is obtained through a phenomenon of nuclear magnetic resonance, which is spin resonance of atomic nuclei, by two-dimensionally sampling a nuclear magnetic resonance signal representative of the information of atomic nuclei in a test piece and then changing the two-dimensional data by two-dimensional Fourier transformation. Interpolative extension of the image is achieved without causing any reduction of the resolution by, in execution of such Fourier transformation, zero-filling the data in at least one of the column and row directions in accordance with the extension rate and increasing the number of the two-dimensional data.

Abstract: A surface coil used as a measuring coil in a magnetic resonance apparatus is divided into at least two coil portions having opposite directions of winding and enclosing two identical surface areas. An induction current generated in a coil portion by a transmission field is then always compensated for by a current generated in the other coil portion. When one or more of such butterfly coils are used no circuits to block interfering signals need be built into the electronic measuring circuit and the transmission field is not disturbed by the measuring coil.

Abstract: A spin echo (52) and a gradient echo (60) are generated in each magnetic resonance sequence repetition. The spin echo is phase encoded by a phase encode gradient (44) in regular steps spanning about a quarter of k-space. More particularly, steps from -n to G.sub.max /2, where n is a small integer and G.sub.max is the maximum phase encode gradient. An off-set phase encode gradient (58) shifts the phase encoding of the gradient echo by G.sub.max /2 relative to the first phase encoding gradient. Data to fill the empty portions of k-space (142, 167) between -n and -G.sub.max are generated from the complex conjugate (140, 160), of the first echo data (74) and the second echo data (76). The first and second echo data and the complex conjugate data are transformed (122, 132, 146, 166) to generate parted image representations (124, 134, 148, 168).

Abstract: Method and apparatus for determining vertical density profiles in wood composites. A fly cutter is rotated across the edge of a wood composite panel to produce acoustic emissions that themselves produce an RMS voltage. The changes is RMS voltage so produced are recorded and thereby the acoustic emission is recorded. The detected signal is transformed into electrical signals, amplified and transmitted to a suitable detecting transducer.

Abstract: A method and related apparatus are provided for correcting for a phase error in MRI observed values which represent a scan line which passes through the origin of Fourier space. The phase error is estimated by calculating the phase of the sum of the observed values. The observed values are then modified as a function of the estimated phase error. To minimize the effect of T.sub.2 decay, the phase error may be estimated by calculating the phase of the sum of the product of each pair of observed values on the scan line which have been relocated symmetrically, one on each side of the Fourier space origin.

Abstract: There is disclosed an apparatus for use in an aerated bath comprising a sensor to sense mass concentration within a liquid, a dedubbler for forcing bubbles from the portion of the liquid to be sensed by the sensor, away from the sensor, and a flow limiter to limit liquid flow past the sensor to no more than that rate at which the debubbler can force bubbles away from the portion to be sensed. The debubbler removes bubbles and the sensor senses mass concentration without removal of liquid from the confines of the bath and before the liquid portion is reaerated by the bath. A process of sensing in the absence of bubbles is also disclosed.

Abstract: A method for ultrasonically detecting flaws in a welded portion of a pipe by using an ultrasonic wave phased array probe having an array of a plurality of transducer elements for emitting and receiving ultrasonic wave beams, wherein at least one monitoring probe is located in the vicinity of the welded portion to receive the ultrasonic wave beam, whereby peak values of the ultrasonic wave beams are detected within a predetermined gate, a maximum peak value of the detected peak values is determined to determine a pilot beam having the maximum peak value, and effective beams which reach the portion of the welding portion to be tested are determined from the determined pilot beam.

Abstract: Defects are detected in cylindrical rods, tubes or the like by a stationary transmission and receiving device arranged along the path which the test object passes axially by providing per test cycle a particular pulse being split for propagating bidirectionally azimuthally in the test object; both pulses are received repeatedly, once per circulation, so that a plurality of pulses appear with gradually declining amplitude; a sequence of burst signals, each of limited duration, is provided for purposes of timing and gating the burst being repeated per circulation on the basis of the expected and known propagation time between transmission and receiving portions; peaks of the received signal are detected once or twice per circulation and in synchronism with the timing and gating signal; the respective detected peak signals are digitized, summed in groups and the quotient of the sums is formed as quality indicator.

Abstract: The invention relates to a system for determining the current thickness of changing coatings of a material on a substrate, using an electrically excitable, mechanically vibratable element (2) having at least one pronounced resonant frequency, which is excited to a steady vibration by an oscillator circuit (1) at a resonant frequency, and which is covered by the material in the same manner as the substrate. A signal (U.sub.D) is produced which depends on the damping caused by the coating of the vibratable element (2). This signal (U.sub.D) is compared with a known critical value signal (U.sub.DE) whereby it is possible to indicate when the vibratable element (2), which can be coated with the material only to a certain degree, must be replaced with a new vibratable element (FIG. 2).

Abstract: In a magnetic resonance imaging apparatus comprising a surface coil, the circuit in which the surface coil is included is interrupted by means of a PIN diode in the non-active state of the coil. In addition to the PIN diode in the resonant circuit of the surface coil, PIN diodes are included in all supply leads of the resonant circuit. An advantage thereof consists in that no RF currents will flow in the supply leads and that the induction voltages generated in the surface coil in the active state of the transmitter coil of the device are actually rectified by the diodes and themselves form a blocking voltage for the PIN diodes included in the circuit. As a result, the biasing of the PIN diodes is increased, so that they remain blocked.

Abstract: Ultrasonic leak detection apparatus which includes a cycloidal transfer mechanism for sequentially feeding a plurality of workpieces to a test station. An elevator at the test station alternately lifts workpieces in sequence to an elevated position to a test chamber and lowers workpieces from the test chamber to the transfer mechanism. An enclosure cooperates with the elevator to form the test chamber in which the workpiece is pressurized and microphones detect any leakage of air through cracks or the like. A reject station downstream of the test station includes facility for removing defective workpieces from the transfer line.

Abstract: A system and apparatus for ultrasonic pulse echo inspection of corners in laminated parts. A variable angle transducer including transducer, fixed reflector, and rotating reflector which effects scanning of the radial arc being tested by the sonic output from the transducer provides ultrasonic information which is processed through an ultrasonic signal processing system which digitizes, stores and displays the information.

Abstract: A sensor for acoustic shockwave pulses, such as in lithotripsy, includes a piezo-electric measuring membrane disposed between two coupling membranes. The intervening space between the coupling membranes is filled with a coupling medium for transmitting the acoustic shockwave pulses. The measuring membrane is in a defined condition largely independent of external influences so that flows in the coupling medium or different pressure exertions on the two coupling membranes do not influence the measured signal produced by the measuring membrane.

Abstract: An apparatus for measuring a dimension of an object by using ultrasonic waves includes: a pair of probes spaced apart one of the probes being to face a top surface of the object and the other of the probes being to face a bottom surface of the object; control for choosing what to be currently measured from three kinds of travelling periods of time which ultrasonic pulses take: to propagate between the probes; to travel between the top surface of the object and the probe facing the top surface; and to travel between the bottom surface of the object and the other probe facing the bottom surface and apparatus responsive to the transmission and reception signals for evaluating the three kinds of travelling periods of time and for calculating the dimension of the object from the evaluated travelling periods, whereby the probes can be out of touch with the surfaces of the object.

Abstract: A speed of movement of a moving object, e.g., a tennis ball, which moves a predetermined distance is determined by measuring a time interval between a first detection of a vibration wave produced in the ball when it is hit by the tennis player's racket and a second detection of anouther vibration wave produced when the ball collides with the court surface. A vibration sensor for performing the first detection, and a microcomputer for computing the movement speed of the ball, and a liquid crystal display for displaying the movement speed are accommodated in a case which is mounted on the tennis racket. A sound collecting micrphone which performs the second detection is attached to the lower edge of the net near a ball landing position on the court, and the detection signal is transmitted over a radiowave to a receiver accommodated in the case.

Abstract: Apparatus and method for detecting torsional vibrations of the shaft of an exciter of a turbine-generator, according to which a permanent magnet generator is connected to be driven by the exciter shaft and has an electrical output for providing an output voltage having a frequency proportional to the rate of rotation of the exciter shaft; and the electrical output is connected to signal processing circuitry serving to derive a signal representative of torsional vibrations experienced by the exciter shaft.

Abstract: Self-shielded gradient coils are used to eliminate interactions between gradient coils and external structure. Interactions between gradient coils for different gradient axes are controlled by means of a balanced interconnection within each separate gradient coil set. One or both of the inner and outer coils within a gradient coil set are split such that for any localized capacitive current flow between coil sets there will be an equal and opposite current flow somewhere else between the coil sets.

Abstract: A method of, and apparatus for, evaluating forming capabilities of metal plate by means of ultrasonic waves where the rolling direction and the density of the plate are known. The method comprises the steps of launching acoustic waves into the plate and detecting acoustic waves propagating in the plate to establish acoustic velocities in the plate along at least two different directions. Then the value of a certain plastic strain characteristic, like the average plastic strain ratio R or the planar strain ratio .DELTA.R, is determined from a previously established empirical relationship between the velocities and the value of the plastic strain ratio R(.alpha.).

Abstract: A method is disclosed for eliminating aberrations in position-time data provided by an apparatus which monitors the position of a rotating blade in a turbo machine as a function periodic rotation, the apparatus including at least one sensor adjacent at least one blade position to provide a time signal corresponding to the actual arrival time required for a blade to move from a predetermined position to the at least one sensor position, the aberrations being caused by misalignment or movement of the at least one sensor with respect to a rotating blade. The method comprises the steps of first calculating an average blade arrival time for blade movement from the predetermined position to the at least one sensor position, and then estimating sensor position relative to the predetermined position based on blade velocity and average arrival time.

Abstract: An external magnetic field is first measured with a certain degree of accuracy using an ancillary (for example, Hall effect) magnetic field measurement device. This measured value is used to calculate an estimate of the nuclear magnetic resonance frequency of a substance placed in the magnetic field. Thereafter, the magnetic field is more accurately determined by varying a bias magnetic field over a range and measuring the variation of the inductance characteristics of a high-frequency coil surrounding the substance which is transmitting at the estimated NMR resonance frequency. By strategically choosing the range of values of bias coil current which produce the bias magnetic field, the invention repeatedly narrows the range in which the magnetic resonance effect can occur so as to derive successively more accurate estimations of the bias coil current occurring at the resonance point, until a predetermined accuracy is attained.