Abstract: Apparatus is disclosed for determining the resistivity of formations surrounding an earth borehole. An electrically conductive metal body, such as a drill collar on a drill string, is movable through the borehole. A transmitting toroidal coil antenna is disposed on the body and is energized to induce a current which travels in a path that includes the body and the formations. An electrode is disposed on the body, and an electrical signal resulting from said current is measured at the electrode to obtain an indication of the resistivity of the formations. In a disclosed embodiment, one or more electrodes can be mounted on a blade that is mechanically coupled to the body.

Abstract: A technique is disclosed for determining properties of an anisotropic elastic medium, such as earth formations. Acoustic waves are established in the medium. At several spaced locations in the medium, there are measured at least two orthogonal components of acoustic waves which have propagated through the medium. For positions corresponding to a plurality of adjacent ones of the spaced locations, there are computed model composite waves which would result from the superposition of a plurality of model acoustic waves, each having selected model parameters. The model acoustic waves include a plurality of model acoustic shear waves and the model parameters include model velocities and model polarizations for each of the model acoustic shear waves. An error value is determined, the error value depending on the differences, at each of the plurality of adjacent ones of the locations, between measured wave components and the model composite wave. The model parameters are then modified.

Abstract: In a form of the disclosure, electromagnetic propagation logging measurements are made for several magnetic moment directions of the electromagnetic energy, and can be examined and/or processed retrospectively in order to select the logging information which has a particular desired characteristic, such as the sharpest imaging of bed boundaries. By scanning the magnetic moment over a wide range of angles, one is assured of obtaining logging information that has a desired attribute, such as image sharpness. This can be determined by viewing a recorded log and/or by automatically processing the log data. Information from other ones of the several logs may be useful in optimizing other attributes, such as standoff immunity or signal-to-noise ratio.

Abstract: A disclosed embodiment utilizes one or more toroidal coil antennas mounted, in an insulating medium, on a drill collar to induce currents which travel in a path that includes the drill collar and earth formations around the drill collar. At least one array of electrodes is provided on at least one stabilizer blade of the drill collar and is utilized to detect currents transmitted by toroidal coil antennas which return via the formations to the electrodes laterally; that is, approximately normal to the axis of the drill collar. Signal traces are obtained from measurements taken at respective ones of the transducers, and a dip characteristic of the formations is determined from the signal traces and from signals representing the rotational orientation of the drill collar.

Abstract: An apparatus is disclosed for perforating, testing, and repairing casing in an earth borehole. A device is moveable through the casing. The device can be mounted on a wireline, on tubing, or on both. A perforator is mounted in the device for producing a perforation in the casing. The device will also generally include components for hydraulic testing/sampling from the formations behind the casing. A plugger is mounted in the device for plugging the perforation with a solid plug or a non-solid sealant.

Abstract: A method of joining a covering layer (9) onto a substrate (10) comprises placing part of the covering layer (9) on the substrate (10) with the remaining part of the covering layer spaced from the substrate so as to expose a region of contact (5) between the covering layer and substrate. A focussed power beam such as a laser or electron beam impinges on the contact region (5) so as to bond or fuse the substrate (10) and covering layer (9) together. The spaced part of the covering layer (9) is then moved towards the substrate (10) so as to change the position of the contact region (5) and the focussed power beam is caused to impinge on the new contact region. These steps are repeated until the covering layer is bonded or fused to the substrate.

Abstract: An apparatus is disclosed for investigating nuclear magnetic resonance properties of earth formations traversed by a borehole, including a logging device adapted for longitudinal movement in the borehole. The device includes a first subsystem for producing a static magnetic field in the formations and a second subsystem for transmitting electromagnetic energy into the formations and for detecting electromagnetic energy from the formations. The second subsystem comprises an antenna assembly which includes an open-ended shell formed of a magnetically permeable material. An open-ended electrically conductive body is disposed within the shell and is spaced therefrom. A medium whose acoustic impedance is substantially different than the acoustic impedance of the shell and the body is disposed between the shell and the body. An electrically conductive probe is disposed in the body, and an electrically insulating magnetically permeable loading material disposed in the body.

Abstract: The disclosure is directed to a transformer circuit apparatus which receives an input signal and generates an output signal representative of the input signal. For example, the input signal may be an AC current, and the output signal to be generated may be a voltage that is proportional to the current. A transformer is provided, and has a core, a primary winding for receiving the input signal, a sense winding, and a feedback winding. A first circuit is coupled to the sense winding, and is responsive to the magnetic flux sensed by the sensed winding, for applying a signal to the feedback winding that tends to reduce the flux sensed by the sense winding. A feedback circuit is provided, and includes a low-pass filter, for feeding back a signal that depends on the output signal to the first circuit means. A circuit is provided for determining the presence of input signal offsets, and for generating offset indication signals in response thereto.

Abstract: A delay circuit for delaying a digital input signal has a ramp generator, a logic circuit which provides a delayed output when the ramp voltage reaches threshold voltage, and a bias circuit which provides bias voltage to the ramp generator so that the delayed output is free from temperature variation, power supply voltage variation and process variation of semiconductor elements.

Abstract: A light scanning system is disclosed which reduces the effects of wobble without the need for complex, cumbersome, or expensive optical equipment. A light source is provided for generating an input light beam. A rotatable support is provided, and has an axis of rotation that is substantially parallel to the input light beam. A reflector subsystem is provided, and includes a plurality of reflector pairs. Each of the reflector pairs is mounted on the support at a different azimuthal location around the axis of the rotatable support. Each of the reflector pairs has first and second light-reflective plane surfaces, the planes of which intersect at an obtuse angle.

Abstract: Electrical equipment which is configurable to operate in a number of modes includes an enclosure, a transparent window in the enclosure through which may be viewed a connector which configures the equipment in a selected mode so enabling a user to determine the mode.

Abstract: A humidity meter includes a humidity-frequency converter which is essentially a pulse oscillator, the frequency of which depends upon the impedance of a humidity sensor, a pulse width modulator for adjusting pulse width of an output pulse of the converter for assuring a linear relationship between humidity and the output signal, and an integrator for integrating the output of the pulse width modulator to provide an output signal as a DC level. A feedback path is provided to apply the output signal to the pulse width modulator for assuring a linear output irrespective of the exponential characteristics of the humidity sensor.

Abstract: Borehole NMR logging apparatus and methods, and methods for the interpretation thereof. A logging tool is provided which produces a strong, static and homogeneous magnetic field B.sub.0 in a Volume of an adjacent formation on one side of the tool to measure nuclear magnetic resonance characteristics thereof. In the preferred embodiment, the tool has an RF antenna mounted on the outside of the metal body of the tool, directing focussed oscillating magnetic fields B.sub.1 at said Volume to polarize or tip the magnetic moments of hydrogen nuclei of fluids within rock pores. The same antenna can be used to receive signals of proton precession in the Volume of interest immediately after transmission of the RF polarizing field B.sub.1. Extremely rapid damping of the antenna between the transmitting and receiving modes of operation is accomplished by a Q-switch disclosed herein. The invention provides for the direct measurement of NMR decay having transverse relaxation time T.sub.

Abstract: Borehole NMR logging apparatus and methods, and methods for the interpretation thereof. A logging tool is provided which produces a strong, static and homogeneous magnetic field B.sub.0 in a Volume of an adjacent formation on one side of the tool to measure nuclear magnetic resonance characteristics thereof. In the preferred embodiment, the tool has an RF antenna mounted on the outside of the metal body of the tool, directing focussed oscillating magnetic fields B.sub.1 at said Volume to polarize or tip the Magnetic moments of hydrogen nuclei of fluids within rock pores. The same antenna can be used to receive signals of proton precession in the Volume of interest immediately after transmission of the RF polarizing field B.sub.1. Extremely rapid damping of the antenna between the transmitting and receiving modes of operation is accomplished by a Q-switch disclosed herein. The invention provides for the direct measurement of NMR decay having transverse relaxation time T.sub.

Abstract: An apparatus and method for determining the position of a movable element. An elongated housing is provided for positioning generally adjacent an edge of an area in which the position of the movable element is to be determined. The housing has a base portion which contains a pair of spaced-apart transducers that are mounted in the surface of the base portion and face the area. An upper body portion of the housing is disposed above the base portion and protrudes in cantilevered fashion toward the area, so that the transducers are recessed from the area beneath the protruding upper body portion of the housing. Circuitry is provided for determining the position of the movable element from the respective transit times of energy propagating in either direction between the movable element and the pair of transducers.

Abstract: The disclosure is directed to an electronic circuit and method for counting input electrical signals. An embodiment of the method of the invention includes the following steps: providing a device having a current versus voltage characteristic with a plurality of peaks, and negative resistance regions between the peaks; generating a triggering pulse in response to each input signal to be counted, and applying said triggering pulse to the device to change the voltage across the device; and outputting the voltage across the device as an indication of the number of received input signals. The device may be a resonant tunneling diode with multiple peaks in its current versus voltage characteristic. The preferred embodiment of the method of the invention includes the step of providing a load resistance means across the device. In this embodiment, the triggering pulse is operative to change the voltage across the device to a stable operating point of the device in conjunction with the load resistance means.

Abstract: System for mounting a piezoelectric vibrator comprises an annular projected vibrator support (27) integrally formed with an insulating support (21), a piezoelectric vibrator (1) located on the annular vibrator support (27) and an elastic annular holder (22) having an essentially L-shaped section for holding down the periphery of the piezoelectric vibrator (1) fitted to the insulating support (21), a plurality of connecting electrode members (23,24) being mounted on the vibrator support (27) and each of the connecting electrode members (23,24) being pressed against the corresponding electrodes (2B,2A') of the piezoelectric vibrator (1).

Abstract: An ultrasonic atomizer circuit having a plurality of unit oscillator circuits has been improved by preventing undesired interference between oscillator circuits. Each unit oscillator circuit has a transistor (Q1) with a grounded collector, a piezo-electric vibrator (TD) coupled across the collector and the base of the transistor (Q1), a capacitor (C3) coupled across the emitter and the base of the transistor (Q1), and a capacitor (C1) coupled across the emitter and the collector of the transistor (Q1). An additional capacitor (C7) is provided between the base of the transistor (Q1) and the junction point of one end of the vibrator (TD) and the capacitor (C3), so that one end of said capacitor (C3) is separated from the base of the transistor for DC current.

Abstract: An X-ray imaging system for obtaining a photographic image of the X-ray transmissivity of a body is disclosed. A source of X-rays is directable at the body, and an X-ray imaging subsystem is provided for receiving a pattern of X-rays transmitted through the body, including, in combination: a first X-ray-sensitive screen for converting the pattern of X-rays to a first pattern of light; a light-sensitive film adjacent the first X-ray sensitive screen for receiving the first pattern of light; a second X-ray sensitive screen for also converting the pattern of X-rays to the first pattern of light; an array of light detecting devices positioned to receive the first pattern of light from the second X-ray sensitive screen; means for storing electronic representations of the outputs of the array of light detecting devices; and light generating means responsive to the stored electronic representations for generating a second pattern of light which is directed at and received by the light-sensitive film.

Abstract: An apparatus is disclosed for digitizing positions on a transparency. The apparatus includes a cool light box and an acoustic digitizer.