Abstract: A cam is immersed in water at an elevated temperature and/or pressure. A reciprocating cam follower also immersed in the water contacts a surface of the cam. The cam follower includes a permanent magnet. An electrically conductive coil is magnetically coupled with the permanent magnet such that movement of the cam follower induces an electrical signal in the electrically conductive coil. A sealed housing also immersed in the water contains the electrically conductive coil and seals it from contact with the water. Leads of the coil are electrically accessible from outside the sealed housing and from outside the water. Alternatively, the cam includes magnetic inserts, the cam follower is replaced by a sensor arm of magnetic material, and the sensor arm and/or the inserts are magnetized whereby rotation of the rotary element causes time modulation of the magnetic coupling and induces coil voltage.

Abstract: A method for mapping geological structures of a formation on a side of a surface, includes: generating a magnetic moment using at least one magnetic moment generator to build up a magnetic field in the formation in an on-period, wherein the magnetic moment has a moment strength, and wherein the magnetic moment is positioned on another side of the surface; changing the magnetic moment to change the magnetic field; and making at least one record in a recording device at a recording time trecord in an off-period, wherein the record includes at least a representation of the change in the magnetic field and/or a representation of the magnetic field obtained by a B/E-measuring unit; wherein the on-period is separated from the off-period by the act of changing the magnetic moment.

Abstract: A system for testing a PSU includes an input control module, a voltage regulating module, and a load adjusting module. The input control module includes a microcontroller and a plurality of key switches connected to the microcontroller. The microcontroller is configured to receive input instruction from the plurality of key switches and output a control signal according to the input instruction. The voltage regulating module is configured to receive the control signal and generate an output voltage with a voltage value associated with the control signal. The load adjusting module includes a motor coupled to the output voltage of the voltage regulating module. The motor is rotatable in opposite direction to adjust an output current of the PSU. A rotating speed of the motor is in direct proportion to the voltage value of the output voltage.

Abstract: Rotation of a magnetized rotor is detected in a highly accurate manner without depending on a magnetic pole pitch of N and S poles of the magnetized rotor. To that end, a magnetic detection device includes a magnetoresistive element that is formed of a fixed layer made of a ferromagnetic material whose magnetization direction is fixed and a free layer made of a ferromagnetic material whose magnetization direction can be freely changed, with a non-magnetic middle layer sandwiched between the layers, and arranged therein maintaining a gap between the element and the outer circumferential surface of the magnetized rotor in which the N and S poles are alternately arranged along the outer circumference rotating around a rotation shaft, wherein the magnetoresistive element is arranged in such a way that a plane on which the fixed layer is formed is in a plane including the rotation shaft.

Abstract: A magnetic susceptibility tomographic device has sensitive magnetic sensors about a measurement volume and AC bias coils for providing magnetic fields within the volume. Sensing circuitry reads the sensors, and a processor executes magnetic susceptibility tomography (MST) routines from memory to divide the measurement volume into voxels, to determine differences between applied and measured field strengths of magnetic fields at each voxel and thereby determines magnetic susceptibility of each voxel, and to construct tomographic images representative of magnetic susceptibility as MST images. Embodiments with SQUID and fluxgate sensors are described. Applications to direct measurement of tissue magnetic susceptibility, and to locating and quantifying tagged magnetic nanoparticles are disclosed, including antibody-tagged nanoparticles for use in cancer diagnosis and treatments, and the retrieval of taggant identification codes from an object.

Abstract: A sensor assembly is sandwiched together with a rubber material mixed with a vulcanizing agent in a mold assembly including an upper mold and a lower mold. The upper and lower molds, while completely sandwiching the sensor assembly, are heated for a predetermined length of time, and a pressure is then applied to the sensor assembly to complete a compressive molding.

Abstract: Electromagnetic (EM) survey processing comprising operating an electronic device to model expected EM field components to be measured by an EM apparatus associated with a subterranean formation, wherein the EM apparatus comprises at least one EM source and at least one EM receiver. The electronic device may be operated to determine one or more ratios of the modeled EM field components. The at least one EM source may be operated to emit an EM signal into the subterranean formation, and the at least one EM receiver may be operated to measure actual EM field components of the EM signal. The electronic device may then be operated to compare the one or more ratios of the modeled EM field components with one or more ratios of the actual EM field components. The one or more ratios of the modeled EM field components may then be updated based on the comparison.

Abstract: A device for focusing a laser in which a voice coil and LVDT are mounted in parallel alignment with each other and have a common centrally disposed armature. A central bore extends through the armature. A lens is mounted at one end of the armature and a laser is located at the opposite end. The laser beam passes through the central bore and is focused by the voice coil moving the armature which in turn moves the lens. The LVDT accurately positions the armature to focus the laser beam.

Abstract: A damage detecting device according to one aspect of the present invention comprises a first speed generator, a second speed generator, a first waveform shaping section, a second waveform shaping section, and a determining section. The determining section compares a second rectangular wave shaped by the second waveform shaping section and a first rectangular wave shaped by the first waveform shaping section and, if the first rectangular wave is not output while the second rectangular wave is output, determines that a supporting device for an armature shaft is damaged or worn.

Abstract: A sensor includes a magnetic piece with a magnetic array, a conductive coil and ferromagnetic object. The magnetic array provides a spatially modulated magnetic field that is concentrated in the near-field. A processor calculates the ferromagnetic object's speed based on voltage induced in the conductive coil. The ferromagnetic object's movement through the magnetic field causes a change in the magnetic flux, and the rate of change is proportional to the induced voltage.

Abstract: Disclosed are methods and systems for conditioning electrodes while deployed in the sea with a marine electromagnetic survey system. An embodiment of the method may comprise deploying electrodes in seawater during a marine electromagnetic survey. The method further may comprise coupling at least one of the electrodes to a controllable current/voltage source while the electrodes are deployed in the seawater. The method further may comprise sending a first conditioning signal from the controllable current/voltage source to the at least one of the electrodes coupled to the controllable current/voltage source.

Abstract: A steering tool is movable by a drill string to form an underground bore along an intended path. A sensing arrangement of the steering tool detects its pitch and yaw orientations at a series of spaced apart positions along the bore, each position is characterized by a measured extension of the drill string. The steering tool further includes a receiver. At least one marker is positioned proximate to the intended path, for transmitting a rotating dipole field to expose a portion of the intended path to the field for reception by the receiver. The detected pitch orientation, the detected yaw orientation and the measured extension of the drill string are used in conjunction with magnetic information from the receiver to locate the steering tool. The steering tool may automatically use the magnetic information when it is available. A customized overall position determination accuracy can be provided along the intended path.

Abstract: Embodiments relate to magnetic field angle sensing systems and methods.

Abstract: A magnetic field sensor for sensing an external magnetic field includes at least one magnetic field sensing element for measuring a magnetic field produced by a first magnetic field generating source and a current generator configured to receive one or more drive current signals at an input thereof and to generate a drive current signal having a periodic waveform and an amplitude offset at an output thereof. Also included is a second magnetic field generating source configured to receive the drive current signal at an input thereof and in response thereto, provide a magnetic field to the at least one magnetic field sensing element. Additionally included is a comparator configured to receive a reference voltage as a first input and an output signal from the at least one magnetic field sensing element as a second input, and in response thereto to generate a comparator output signal having a duty cycle.

Abstract: A method and apparatus for testing near field magnetic fields of electronic devices. The method comprises measuring a magnetic field using a loop antenna that is oriented in a first direction. The loop antenna is swept through a desired range of azimuth angles while measuring the magnetic field. Once the first direction testing is completed, the loop antenna is changed to a second orientation direction. The magnetic field is then measured in the second orientation direction and is swept through a desired range of orientation angles in the second direction. The apparatus provides a loop antenna connected to a coaxial probe, with the coaxial cable serving as the center conductor, and two outer conductors. An axle is mounted to the loop antenna and connected to a step motor. A servo motor is also provided for moving the arm assembly.

Abstract: Disclosed herein are electromagnetic resistivity logging systems and methods that employ an antenna configuration having at most two transmitter or receiver antenna orientations that rotate relative to the borehole. The measurements made by this reduced-complexity antenna configuration enable the determination of at least seven components of a coupling matrix, which may be determined using a linear system of equations that express the azimuthal dependence of the measurements. For increased reliability, measurement averaging may be performed in azimuthally spaced bins. The coupling matrix components can then be used as the basis for determining logs of various formation parameters, including vertical resistivity and anisotropy.

Abstract: A multi-layer eddy current sensor includes a sense coil for detecting an eddy current, and a drive conductor for inducing the eddy current. The drive conductor comprises a substantially straight conducting portion that traverses the entire width of the sense coil.

Abstract: A downhole activation system within a tubular. The system includes an axially movable member; a first magnetic field source having a first field with a first axial orientation movable with the member. A second magnetic field source having a second field with an axial orientation different from the first orientation and separated from the first magnetic field source. The second field being magnetically repulsed by the first field; and, a biasing device urging the second magnetic field source towards the first magnetic field source; wherein movement of the first magnet via the member towards the second magnet moves the second magnet in a direction against the biasing device. A method of activating an activatable member in a downhole tubular.

Abstract: A vertical Hall effect device is provided and includes a Hall effect layer having a first, second, third, and fourth Hall effect region, which are at least partly decoupled from each other. The Hall effect layer has first and second opposite faces and the vertical Hall effect device has a terminal composition comprising a first, second, third and fourth terminal. A low ohmic connecting composition at the first face connects the terminal composition with contacts of the Hall effect regions so that at each Hall effect region the terminal composition is connected to a same first number of at least two contacts being connected to the respective Hall effect region at the first face. The second and third terminals selectively output an electrical signal responsive to a magnetic field, and the first and fourth terminals selectively output the electrical signal responsive to the magnetic field.

Abstract: A device rotates at least one static magnetic field about an axis, producing a rotating magnetic dipole field, and is movable in relation to the surface of the ground. The field is periodically sensed using a receiver to produce a receiver output responsive to the field. A positional relationship between the receiver and the device is monitored using the output. In one aspect, changing the positional relationship, by moving the device nearer to a boring tool which supports the receiver, causes an increase in accuracy of depth determination. In another aspect, determination of an actual overhead position of the boring tool, and its application, are described. Use of a plurality of measurements over at least one-half revolution of each magnet is disclosed. Establishing a surface radial direction toward a boring tool and resolution of multi-valued parameters is described. Calibration techniques, as well as a three transmitter configuration are also described.