Abstract: An arrangement for determining the direction of movement of a motion sensor element, requiring only two sensor elements, which, in a first zone having a first pitch and extending in the form of strips along a motion co-ordinate describing a movement of the motion sensor element, comprises periodically recurrent areas alternately influencing a first magnetic field, and, in a second zone having a second pitch and extending in the form of strips along the motion co-ordinate, comprises periodically recurrent areas alternately influencing a second magnetic field, the arrangement comprising a first sensor element for detecting the influence on the first magnetic field by the first zone of the motion sensor element, and a second sensor element for detecting the influence on the second magnetic field by the second zone of the motion sensor element, the first pitch of the first zone being in an odd, integral ratio to the second pitch of the second zone, such as 1:3, 1:5, etc.

Abstract: The invention subject of this application pertains to a method and apparatus for measuring the subterranean lithology using electromagnetic energy. The invention is applicable to the measurement from within uncased boreholes, i.e., and open-holes. The present invention transmits and receives electromagnetic energy deep into a geologic formation from a borehole, while also providing high resolution for distant measurements and the ability to control the direction in which the measurements are taken. The invention does not require a receiver to be located at the ground surface or in another borehole. In simple terms, the apparatus of this invention is able to “look around” into the surrounding geologic formation from a stationary position.

Abstract: The present invention provides a method for the direct measurement and quantification of the material volume loss on and beneath a first surface of a substrate and thus provides an accurate depiction of the profile of the substrate. The method of the invention comprises inducing multiple eddy currents in a test substrate to determine volume loss.

Abstract: The invention relates to techniques for locating and determining the orientation of a fracture in an earth formation. Systems and methods for detecting a fracture in an earth formation using a propagation tool include producing electromagnetic fields using a TMD transmitter in the tool; measuring corresponding voltage signals detected with one or more TMD receivers in the tool; determining harmonics from the measured signal responses by shifting the responses (e.g. by 90 degrees) and performing an addition or subtraction using the shifted response. In some embodiments, the second harmonic is processed to determine the fracture orientation.

Abstract: A sensor measurement of an article having an article surface shape is performed using a hand-held senor probe having a probe housing, a sensor support rotatably mounted in the probe housing and having an orienting structure defined thereon. The orienting structure is preferably an orienting face with substantially the article surface shape. A sensor, such as a eddy current sensor, is affixed to the sensor support and is operable through the orienting face of the sensor support. The orienting face of the sensor support is pressed against the article surface to orient the sensor support and thence the sensor relative to the article surface, and the sensor measurement is performed. The sensor is preferably a ball having the orienting face thereon, and mounted to the probe housing in a ball-and-socket relationship.

Abstract: A magnetic detection element suitable for detecting a strength of an external magnetic field, has a magnetic thin film formed on a single non-magnetic substrate, a circuit that applies a high-frequency current to the magnetic thin film, and a spiral-type planar coil that is stacked on the magnetic thin film with an insulating layer, in between. The magnetic thin film is formed in a longitudinal shape, and magnetic anisotropy is provided such that the direction of easy magnetization is orthogonal to the longitudinal direction of the longitudinal shape.

Abstract: A magnetic field sensor relies on variations in permeability of magnetic material to detect an external field. An exemplary magnetic field sensor includes a magnetic material and two or more conductors, at least one of which is connected to an electrical energy source. Current flowing through at least one of the conductors establishes a magnetic field in die magnetic material at a magnitude at which there is a generally linear relationship between the magnetic field and the permeability of the material. An external field to be sensed influences the permeability of the material. Sensing variations in the permeability of the magnetic material allows the external magnetic field to be sensed.

Abstract: A rotational speed detector such as a wheel speed detector has an elongate housing containing a detector unit therein. The detector unit is a molded unit having a sensor element and an integrated circuit chip for processing sensor signals. A front wall of the elongate housing faces a magnetized rotor rotated by a rotating object so that the rotational speed of the rotor is detected by the detector unit. After the housing and a center rod having a terminal wire for leading out the detected electrical signals are connected to each other, a resin mold covering an outside of the center rod and a part of the housing is formed to formulate a unitary body of the rotational speed detector.

Abstract: A sea-floor electromagnetic measurement device for obtaining underwater measurements of earth formations including a central structure and arms attached to the central structure so that they can pivot relative to the central structure. An electrode is attached to the end of each of the arms or to the central structure, and/or magnetometers are attached to the arms. A method for undertaking sea-floor electromagnetic measurements of earth formations including measuring electric fields at a selected distance from a central structure of an electromagnetic measurement system. Magnetic fields are then measured at the same location.

Abstract: A sensor attachment structure is provided with grooves for attaching, to an actuator body, magnetism-detecting sensors each of which is constructed to have a substantially rectangular cross section. The groove is designed to have a substantially rectangular open cross section. The groove includes a tapered section which has widths gradually narrowed inwardly from the contour surface, and a spread section which is spread from narrow width ends of the tapered section and to which pawls of the magnetism-detecting sensor are installed.

Abstract: Methods and apparatus are disclosed determining the presence of base line popping noise for a read head inside an assembled disk drive, as well as, determining read bias conditions for operating the read head free of base line popping noise. These further include performance evaluation of the read head for read bias conditions free of base line popping noise. They also include repairing the read head using DC write current and read bias current within the assembled disk drive.

Abstract: A wand-type magnetic metal detector has a telescoping wand which shortens the wand sufficiently for the detector to be comfortably carried in a holster carried on the user's body. The user's hands are thereby freed for other tasks than carrying the detector.

Abstract: The present invention is for a precision grid surveyor having a stationary unit and a roving unit. The stationary unit has a light source unit that emits a light beam and a rotator to project the light beam toward detectors on a roving unit. The roving unit moves over an area to be surveyed. Further the invention is for a method of mapping details of hidden underground iron pipelines, and more particularly the location of bell joints.

Abstract: The invention is a method of determining horizontal and vertical resistivity in an anisotropic formation using a combination of orientable triaxial and array antennae conveyed downhole. Measurements are taken at various azimuthal angles about a measuring device at a given depth. Values at each azimuthal orientation can be fit to a curve to yield information on the surrounding formation. Multiple measurements at a given depth and azimuthal orientation can be weighted to obtain an average value. Values from the curve fitting process are used in subsequent inversion processing and reduce the uncertainty of the inversion processing result. Utilization of a three dimensional geometry enables a unique resolution of the orientation of the principle axis of anisotropy, and consequently of horizontal and vertical resistivity, and dip.

Abstract: An apparatus can detect a magnetic field with a high sensitivity using an ordinary-temperature pickup coil even when the pickup coil is arranged outside a cryostat. Specifically, the apparatus for measuring a magnetic field includes a pickup coil for detecting an external magnetic field, a SQUID electrically or magnetically connected to the pickup coil, a cryostat for holding the SQUID at low temperatures, and a driving device for driving the SQUID. The pickup coil is made of a normal-conducting material and is placed at an ordinary temperature outside the cryostat. By arranging outside the cryostat, the pickup coil can be brought close to a subject and can thereby detect a weak magnetic field in the subject with a high sensitivity.

Abstract: Using micro-resistivity techniques, an image of the wall of a borehole can be obtained. A downhole tool stack is provided with plural imaging tools, wherein each imaging tool has a set of pads that deploy radially outward to contact the borehole wall to obtain the image thereof. As the pads deploy outwardly, gaps are formed between the pads. The pads of one tool are circumferentially offset relative to the pads of the other tool so that more complete circumferential coverage of the borehole wall is obtained during the imaging process. Furthermore, an adaptive polling technique is utilized to telemeter the large amounts of data generated by the two imaging tools to the surface. Data is obtained from the imaging tools by polling at a particular rate, which rate is modified depending upon the amount of data generated by the imaging tools.

Abstract: A body detecting element is buried in the ground together with a body such as a metal body and includes a magnetic member acting as a magnetic core, an antenna coil wound around the magnetic member and a capacitor connected to both the ends of the antenna coil for forming a resonance circuit together with the antenna coil. The antenna coil is mounted on the body integrally therewith through an electromagnetic shield member with the outer peripheral surface thereof confronting the outer surface of the body. A body detecting element includes an RFID circuit connected to the antenna coil and mounted on a body integrally therewith such that the outer peripheral surface of the antenna coil confronts the outer surface of the body through an electromagnetic shield member. Even if the body detecting element is mounted on the body such as the metal pipe integrally therewith, it can accurately detect the body because a resonant frequency and the Q value of the coil are not changed.

Abstract: A device operative to detect metal objects. The device includes a transmitter circuit, an upper transmitter coil and a lower transmitter coil operatively connected to the transmitter circuit. A current fed through the upper transmitter coil and the lower transmitter coil generates a field that excites eddy currents in metal objects in the vicinity of the upper transmitter coil and the lower transmitter coil. An upper magnetic field detector and a lower magnetic field detector are operative to sense eddy currents generated in the metal objects. Processor elements operatively connected to the upper magnetic field detector and the lower magnetic field detector collect, store and analyze the eddy currents and thereby determine the likelihood that a metal object has been detected. A navigation system operatively connected to the processor elements controls movement of the device.

Abstract: Angular position sensing apparatuses and methods are disclosed. An angular position sensing apparatus can include a rotatable base and two or more magnets located proximate to one another upon the rotatable base. The magnets are generally magnetized parallel and opposite to one another to create a uniform magnetic field thereof. Additionally, a sensor can be located external to the two magnets, such that the sensor comes into contact with the uniform magnetic field to sense a change in angular position associated with the rotatable base.

Abstract: A proximity probe system comprising a multi-coil proximity probe including a drive coil, a sense coil and a reference coil. The system includes a signal generator driving the drive coil with an alternating current for creating a magnetic field that induces eddy currents in a proximate conductive object resulting in an eddy current induced magnetic field emanating therefrom. The sense coil is interposed between the object and the drive coil for outputting an object induced alternating current that is detected by the system and correlated to a position of the object relative to the probe. The reference coil is positioned to be inductively coupled to the drive coil for carrying a drive coil induced alternating current that is detected, conditioned and feedback to the signal generator for controlling the magnetic field radiating from the drive coil while sensing the the object induced alternating current in the sense coil.