Abstract: A nuclear magnetic resonance spin density distribution in a sample is obtained for a selected plane or planes by placing the sample in a static magnetic field, applying a gradient to the field and simultaneously applying selective rf pulses to select a plane or planes in the sample, switching to an orthogonal gradient and simultaneously applying selective rf pulses to select strips in the selected plane or planes and then applying orthogonal field gradients to the sample of such relative magnitudes that each point of the selected strips is subjected to a resultant magnetic field of amplitude unique to that point. The free induction decay signal is then read out from the strips.

Abstract: Apparatus for measuring magnetic field strength which comprises two Nuclear Magnetic Resonance cells (the NMR cells), a field generator for applying to the NMR cells bias magnetic field which is parallel and of substantially equal strength at each NMR cell, an excitation assembly for separately magnetically exciting each NMR cell at its own Larmor precession, or resonance, frequency, and a device for deriving a signal in accord with the difference between the Larmor frequencies of the two cells.

Abstract: An electrochemical reference cell has a reference electrode disposed at one end of a rigid hollow cylinder immersed in an electrolyte solution of known concentration. Different interlocking series of plugs, consisting of a material such as wood, with semipermeable, longitudinally extending capillaries, are fitted together in abutting relation to fill the hollow interior of the cylinder between the reference cell and the other end with one series longitudinally overlapping the other. The abutting end surfaces of adjacent plugs in each series are sealed to close off the capillary path between successive plugs, whereas the outer surface of the last plug in at least one series is left unsealed to be in contact with the test solution, so that circuitious ion transfer path is established between the reference cell and the test solution that passes tranversely through the longitudinal semipermeable capillary walls from the plugs in one series through adjacent plugs in the other.

Abstract: A digital frequency measuring device in which pulses of an input signal are counted for a certain period of time under the control of a gate signal and the count value is displayed in a digital form. A fraction detector circuit is provided for measuring the time interval or difference .DELTA.T.sub.1 between the leading edge of the gate signal and an input pulse arriving after it, the time interval or difference .DELTA.T.sub.2 between the trailing edge of the gate signal and an input pulse arriving after it and the unit period T of the input pulse signal, and performing an operation corresponding to (.DELTA.T.sub.1 - .DELTA.T.sub.2 /T. The result of operation is converted into the corresponding digital value, which is displayed as a fraction value of the abovesaid count value.

Abstract: An apparatus for measuring the intensity of current produced in an elongated electrical conductive member by a lightning strike for determining the intensity of the lightning strike. The apparatus includes an elongated strip of magnetic material that is carried within an elongated tubular housing. A predetermined electrical signal is recorded along the length of said elongated strip of magnetic material. One end of the magnetic material is positioned closely adjacent the electrically conductive member so that the magnetic field produced by current flowing through said electrically conductive member disturbs a portion of the recorded electrical signal directly proportional to the intensity of the lightning strike.

Abstract: A frequency transducer circuit for providing a precisely adjusted range of output currents characterized by the combination of a diode pump circuit with a low impedance input circuit including a control transistor with a first variable impedance for determining the upper limit of the output range, and a biasing circuit with a second variable impedance for adjusting the lower limit of the output range.Calibration of the output current range is facilitated in one preferred embodiment of the invention by eliminating interaction between the upper and lower range limit adjustments.

Abstract: An NMR (nuclear magnetic resonance) spectrometer has a permanent magnet provided with a field coil. A lock system cyclically pulses a deuterium lock sample to produce a FID (free induction decay) signal that is analyzed by measuring the time interval during which the FID signal crosses the zero axis a predetermined number of times. The measured interval is compared to a predetermined interval or set point, and the current through the field coil is adjusted in the direction tending to correct the field strength so as to maintain the measured interval equal to the preset interval. Such measurement, comparison and adjustment are done several times each second. When the sample is removed, the lock system retains the last field setting achieved with the sample.

Abstract: A method of measuring the quantity of a flowing fluid through the use of nuclear magnetic spin resonance which includes; passing a fluid containing magnetizable nuclei and having portions of different flow velocities through a pipe of non-magnetic electrically insulating material; applying a direct-current magnetic field to the fluid to align the nuclei spin axes thereof; applying an alternating-current magnetic field to the fluid to synchronize the nuclei; and measuring the resultant nuclear magnetization and the velocity of respective different portions of the fluid with respect to time, the sum of the products of velocity and nuclear magnetization of the portions providing a measure of the quantity of the fluid.

Abstract: In a system for converting information in the form of an AC frequency to digital data, a binary number having a magnitude proportional to the frequency is derived by generating a stream of pulses at a known clock rate and counting the number of pulses occurring during a specified period of the AC frequency. A high degree of accuracy is achieved by varying the clock rate as a function of the frequency of the AC signal such that an optimum numeric count is reached. The counter counts the duration of the first half period of the first cycle of the AC signal at a first fixed clock rate. The most significant bits of the generated count are input as a scaling factor to a binary rate multiplier which increases the clock rate in proportion to the magnitude of the scaling factor. The duration of the first half period of the succeeding cycle of the AC signal is then counted at the new rate.

Abstract: A field test set for static trip circuit breakers is electrically connected to the static trip unit and to the circuit breaker trip coil and phase current sensor transformers. The test set, powered from a low voltage source, is equipped to shunt feed the trip unit power supply, bringing the trip unit up to power preparatory to the injection of selected levels of overcurrent and ground fault simulating test signal current for verifying the time-current characteristics and current pickup calibrations of the various trip functions of the trip unit. A lockout circuit automatically terminates a test signal current whose magnitude and duration represents potential harm to the trip unit. The test set is also equipped to test the trip coil energization level developed by the trip unit and also the continuity of the breaker current transformers.

Abstract: A scanner for reading binary digit spots on a transparent film includes a laser light beam which is directed through a beam splitter and through the film to a mirror, from which it is reflected back through the film to illuminate a small area on the film. Light which is not blocked by a recorded spot on the film continues back to the beam splitter, from which the beam is directed to a photodetector. The photodetector is positioned to receive light from solely a portion of the illuminated area of the film, to provide high definition scanning not adversely affected by distortion of the illuminating light beam by imperfections in the film and mirror.

Abstract: A portable ohmmeter for use in measuring the resistance of an electrical contact including a direct current battery, and a resistive element serially connected with the contact and the battery to form a complete circuit. Included are means for sensing the voltage drop across both the resistive element and the contact, and a digital ratiometer for displaying the value of the resistance of the electrical contact. The digital ratiometer displays the ratio of the voltage drop across the contact to the voltage drop across the resistive element, which ratio is also the value of the resistance of the contact. Also included are means for calibrating the ratiometer as a function of the resistance of the resistive element.

Abstract: An apparatus which indicates the sequence of a pair of alternating current input signals by determining the sense of a datum crossing in one input signal with respect to the polarity of the other input signal at the time of the datum crossing.

Abstract: A method and assembly for detecting the presence of a failure in a protective coating on the surface of a metal body which comprises causing an electrolyte to make contact with the protective coating, and making comparison of the electric current generated through the electrolyte(a) between the metal body and a reference-electrode immersed in the electrolyte, and(b) between the same reference-electrode and a similation-electrode immersed in the electrolyte and having a working surface of the same metal as that of the metal body.

Abstract: A volt meter is connected across the battery terminals to read output voltage; a standard load, which may be the normally connected or design load for the storage battery is connected thereacross and, when a predetermined load current flows into the standard load, a control means coupled to the volt meter controls the volt meter to then indicate battery voltage as a measure of remaining stored charge.

Abstract: Magnetic resonance apparatus having an alignment axis which is located in and oriented parallel to a unidirectional field when the apparatus is in operation. The apparatus includes an absorption cell intersected by the alignment axis having a plurality of surface elements surrounding a hollow cell interior in which a magnetic resonance medium is located. The improvement of the invention is the absorption cell having normals to its surface elements which simultaneously form angles of around 55.degree. with lines parallel to the alignment axis.

Abstract: A cathode ray tube having a cathode and first, second and third grid electrodes, is biased "on" to allow an electron current I.sub.K to flow from the cathode to the second and third grid electrodes. During a test period of predetermined length, the peak value of cathode current is stored as a reference measurement I.sub.kp and the cathode current I.sub.k is continuously monitored and compared with I.sub.kp. A failure indication is provided if the magnitude of I.sub.kp - I.sub.k exceeds a predetermined value at any time during the test period.

Abstract: A test assembly and wafer tube holder are provided to permit comparative ts of each elemental surface portion of a tube target as a function of position thereon and as a function of the lifetime of the tube.

Abstract: An elapsed time indicator includes an electrolytic timing cell in series connection with a resistor, which series circuit may be connected to a D.C. voltage. The cell is comprised of an aluminum can containing a liquid electrolyte with an aluminum anode immersed therein. During operation an aluminum oxide film is grown on the surfaces of the anode, the film thickness and resistance increasing with time. The voltage dropped across the cell of any instant is employed as an indication of the accumulated elapsed time during which the D.C. voltage has been connected to the circuit.

Abstract: A beam-of-light (BOL) sensor having means for regulating the intensity of the sensor light source to compensate for extraneous factors in its operating environment, e.g., dust accumulation, component aging, misalignment, etc., that may affect consistent sensor operation. The BOL sensor includes a photosensor whose output signal is compared against a reference signal to determine if the light source intensity is of the proper level. The comparison signal is used to gate clock pulses to a counter to adjust its stored count upward or downward, dependent on whether the light source intensity is low or high, respectively. A filter is provided to override interruptions in the photosensor output signal below a predetermined minimum time duration.