Abstract: A method is provided for detecting geophysical anomalies. Electrical energy is capacitively accumulated with a charging circuit until a breakdown voltage of a switch is reached. Thereafter, the accumulated electrical energy is discharged by passing a discharge current through a transmitter antenna to transmit an electromagnetic pulse into a geophysical region. This technique allows an increase in the strength of an electromagnetic sounding signal, while simultaneously reducing energy consumption, and thereby also permitting smaller weights and dimensions for the power supply.

Abstract: Methods and apparatuses for measuring an electrical property of the ground. The apparatus includes a graphite electrode. The graphite electrode includes a graphite body and a first and second opening. The first opening extends longitudinally throughout the graphite body and is configured to receive a multi-wire cable. The second opening is configured to secure one or more wires of the multi-wire cable to the graphite body. Using a graphite electrode, measurements of the ground can be made over a long period of time without having to clean or otherwise maintain the electrodes because the graphite material withstands operating conditions over many years without degradation.

Abstract: A system and method for gathering and analyzing data captured from one or more remote sensing units positioned in the field. Remote sensing units preferably utilize optical sensors. Power to sensing unit components is preferably selectively controlled to reduce power consumption. Remote sensing units according to the invention can be used for a variety of purposes, including water quality or electrical power monitoring, and data from such sensing units is preferably transmitted to a secure host terminal via a communications link. The host terminal preferably formats, analyzes, and stores the data for customer review and retrieval. If alarm conditions exist that require immediate customer notification, such notification can be sent to a customer via one or more telecommunications means. Through the use of the present invention, businesses can shift from a reactive to a proactive mode of monitoring and operation.

Abstract: An apparatus for determining a velocity of a part through a part feeder tube. The part feeder tube defines an axis. The apparatus includes first and second sensors spaced axially from each other by a predetermined distance (d). The first sensor sends a first signal in response to sensing the part and the second sensor sends a second, subsequent signal in response to sensing the part. The velocity of the part is based on the distance (d) and the first and second signals.

Abstract: Shield apparatus are provided for use with logging instruments equipped with transverse magnetic dipole antennas. Flexible dielectric strips and dielectric cylindrical bodies are implemented with conductive elements in various patterns to form Faraday shield structures. The shields provide an extended conductive surface to the instrument support member and redirect axial currents along the borehole, protecting the underlying antennas from the undesired effects of these currents.

Abstract: A spin valve sensor comprising a ferromagnetic free layer, a ferromagnetic pinned layer, a layer of non-ferromagnetic material positioned between the free layer and the pinned layer, and an antitferromagnetic pinning layer positioned adjacent to the pinned layer such that the pinning layer is in direct contact with the pinned layer. The free layer comprises a multi-layer stack including a non-magnetic insulating spacer positioned between a first and a second ferromagnetic sublayer. The non-magnetic insulating spacer provides a specular electron scattering effect. The first and the second ferromagnetic sublayers each have passive end regions separated by a central active region. The spin valve sensor further includes bias means positioned between the first and the second ferromagnetic sublayers in the passive end regions.

Abstract: An inductive proximity switch includes an electrical resonant circuit and an energy source coupled therewith to compensate for losses in the resonant circuit. The energy source is fully differentially coupled with the resonant circuit at the input side.

Abstract: A microelectromechanical systems (MEMS) Device manufactured on a microscopic scale using integrated circuit techniques provides a sensitive magnetic field sensor by detecting motion caused by the Lorentz force produced by a current through a MEMS conductor. The resulting MEMS may be used as a component in a variety of devices including current sensors and proximity sensors.

Abstract: A motion parameter of an at least partially conducting moving body is measured with a measuring device having at least one coil with a coil axis tangential to the motion direction of the moving body. A primary magnetic field induces electrical currents in the moving body that generate a motion-dependent measuring magnetic field which is measured by the measuring device. The tangential coil(s) has/have a greater distance from the moving body than the primary magnets.

Abstract: A system and method for monitoring the composition of a magnetically permeable material, where the system comprises a first container containing a volume of magnetically permeable material; a flow path for flowing the magnetically permeable material out of the container; a sensor for determining the inductance of the magnetically permeable material; and a sensor for determining the density of the magnetically permeable material. The sensors for determining the density and inductance of the magnetically permeable material are flow connected to the flow path.

Abstract: An electromagnetic wave propagation resistivity borehole logging system comprising multiple groups of electromagnetic transmitter-receiver arrays operating at three frequencies. The borehole logging tool component of the system employs eight transmitters and four receivers. The transmitters and receivers are disposed axially and symmetrically along the major axis of the tool to form four group pairs. Each group pair consists of a transmitter-receiver groups axially and symmetrically on opposing sides of a reference point on the tool. Each, transmitter-receiver group consists of one transmitter assembly and two receiver assemblies. Each transmitter-receiver group is operated at two of three operating frequencies which are 100 kHz, 400 kHz and 2 MHz. The transmitter and receiver assemblies are fabricated to yield azimuthally symmetrical resistivity measurements in a plane essentially perpendicular to the axis of the tool.

Abstract: A reduced-offset induced current position transducer uses a tape scale to inductively couple at least one transmitter winding on a read head to one or more receiver windings on the read head. The at least one transmitter winding generates a primary magnetic field coupled to the tape scale. Apertures in the tape scale determine a pattern of induced current flow in the tape scale, including induced current flow in a region away from the primary magnetic field. At least one receiver winding is inductively coupled to the tape scale in a region away from the primary magnetic field. At least one of the transmitter winding or the receiver windings is formed in a periodic pattern complementary to the configuration of the apertures on the tape scale. Depending on the relative position between the read head and the scale, the receiver windings inductively couple to the tape scale to various degrees. A compact, high accuracy, high resolution inductive position sensor using an economical tape scale results.

Abstract: The present invention provides a position sensor which is suitable for use in a piston and cylinder assembly. The position sensor includes a movable field modifying member which is operable to vary the inductance of a sensor winding, whereby the position of the field modifying member relative to the sensor winding can be determined by monitoring the inductance of the sensor winding. The position sensor also includes a compensation winding which is arranged to have a common coupling with the field modifying member whereby a signal output from the compensation winding can be used to compensate for variations in the signal level output by the sensor winding caused by, for example, temperature variations of the system.

Abstract: A method and system for sensing magnetic fields using an AC current carrying wire which vibrates or moves in the presence of a magnetic field. The system uses the wire movement to determine one or more characteristics of the field. The wire is connected at a first and second location to the base with an portion between the connection locations having an apex spaced apart from the base. The monitoring system detects movement of the wire at the portion while an electrical current having the same frequency as the mechanical resonant frequency of the wire is sent through the wire and a magnetic field surrounds the portion. The reporting system determines one or more characteristics of the magnetic field based upon the detected movements.

Abstract: A magnetic sensor includes first and second members movable relative to each other. One of the members is secured to a movable member and the other fixed. The first member defines a magnetic circuit with an air gap provided with a detector sensitive to the magnetic induction prevailing in the air gap. The second member is a permanent magnet in magnetic coupling relation with the first member. The first member has a tubular portion and a rod-shaped portion, the portions being magnetically coupled, at one end, by the permanent magnet with radial magnetization and, at the other end, by elements for concentrating the magnetic flux in the air gap. The air gap is delimited by these concentration elements and the facing end of the rod-shaped portion of the first member.

Abstract: A magnetic field sensor has a carrier element (1) made from metal, on which a holder (2) with a sensor element (3) is fixed in a set position. For this, the holder (2) engages with holding tongues (9, 10), having barbs (11), in recesses (12, 13) in the holder (2). An interspace (15), filled up by an extrusion coating (16), which also surrounds the remaining holder (2) hermetically, exists between the holder (2) and the carrier element (1) through the bearing of the holder (2) against a stop surface (14) of the holding tongue (9, 10).

Abstract: A method for indexing magnetic disks by using a scanning probe is disclosed. A magnetic disk includes several essentially concentric magnetic tracks. The magnetic disk is attached to a rotating spindle. A number of data tracks is then written in a specific circular arc at an inner radial position of the magnetic disk. The beginning or the end of the written data tracks is defined to be in a co-incident or in a defined relation to an index or trigger signal defined by the rotating spindle. The rotating spindle is stopped from rotation, and a scanning probe microscope is moved radially at a fixed rotating angle to a second radial position. A tip of the scanning probe microscope is moved towards a surface of the magnetic disk. At least one scan line is recorded and analyzed in order to determine if a magnetic track is imaged by the tip of the scanning probe microscope.

Abstract: A method and apparatus to qualify heads to be used in disc drives. The method and apparatus collect a set of track scan data by moving the head across transitions in a track on a medium. The track scan data is changed based on a difference between a writer width of the head and a nominal track width to produce modified track scan data. Position error signal data is then determined from at least some of the data in the modified set of track scan data. The linearity of the position error signal data is used to qualify the head.

Abstract: A magnetic receiver with a magnetically permeable core is positioned inside a wellbore casing and operated in a feedback mode to reduce attenuation of a measurable magnetic field. The receiver employs a feedback device to reduce mutual coupling between the core and the casing, which reduces the otherwise normal attenuation of em signals inside the casing. The feedback device may be provided in the form of an extra or feedback winding that effectively cancels the inducing field inside the core and reduces the attenuation otherwise caused by the core-casing interaction. Alternatively, the magnetic receiver may employ, as the feedback device, a current feedback amplifier circuit to cancel the inducing field inside the core. Specifically, the circuit is operated to produce a secondary magnetic field that essentially cancels the inducing field inside the core.

Abstract: An integrated control-unit and power-supply assembly usable on board a bicycle includes a box for containing an electronic control unit, the box being fixable to the down tube of the bicycle in the area where the bottle cage is fixed, or else underneath the crank case, and being provided with a receptacle-like tubular appendage which receives, by fast-coupling means, the end of a cylindrical battery holder. One end of the cylindrical battery holder carries a sensor device, for example a magnetically operated sensor, which is set at a distance from the crank pin that is substantially equal to the length of the crank arm. The sensor co-operates with a permanent magnet carried by one of the pedals to emit a pulse at each revolution of the crank arms. The assembly according to the invention can be exploited for carrying one or more sensors, of any type.