A wireline width measuring apparatus and associated method which may be used to measure static and dynamic fracture width in fractures used for energy storage, water injection, or hydrocarbon production. In one embodiment, the method comprises determining a depth of the formation fracture, determining the depth of the bottom of the wellbore, positioning a caliper tool string comprising a caliper apparatus at the bottom of the wellbore, wherein the caliper apparatus is positioned at a depth capable of measuring movement of a window cut into a casing of the wellbore at the depth of the formation fracture, inflating the fracture by injecting a fluid into the fracture, uninflating the fracture by producing the fluid from the fracture, and measuring movement of the window cut into the wellbore while the fracture is inflated and uninflated.

A capacitive measurement device for indicating when two surfaces moving relative to each other are spaced less than a predetermined distance apart. The device comprises a probe having an elongated conductor, an insulating core, a conducting inner guard, an insulating interlayer, and a conducting sheath. A portion of the conductor, insulating core and conducting inner guard form a probe tip which extends beyond the insulating interlayer and conducting sheath by a predetermined offset. The probe is configured to extend from a first surface by a predetermined distance and to generate a signal when the tip is contacted by a second surface.

A method for installing a stroke sensor is provided such that the stroke sensor can be easily adjusted using a simple process. The method has the steps of; obtaining a relationship between the magnetic field and the indicator value while moving the magnet in the first direction relative to the magnetic field detecting element within a predetermined relative movable range, and writing the relationship in the processor; after the relationship is written in the processor, preventing the predetermined relative movable range from being shifted in the first direction by means of a jig for preventing positional shift, wherein the jig includes an element that fixes relative positions between the magnetic field detecting element and the magnet; attaching the magnet and the magnetic field detecting element, which have been prevented from being shifted, to different structures that are movable in the first direction relative to each other, and removing the jig.

Aspects of the subject technology relate to a system including a reference device, a measurement device and a processor. The measurement device provides a three-dimensional (3-D) point map corresponding to first positions of a plurality of selected points on a torso of a user. The processor determines a shape of the torso based on the 3-D point map. The measurement device is sequentially placed on the plurality of selected points, and the 3-D point map represents the first positions of the plurality of selected points relative to a second position associated with a location in 3-D space of the reference device.

An arrangement (100, 200, 300) for monitoring of at least one distance between antenna units, the arrangement comprising at least two antenna units (104, 106, 116, 118, 136, 138), each antenna unit being associated with a radio unit (108, 110), the arrangement additionally comprising at least one radio unit being associated with at least one of the at least two antenna units, and at least one processor. The two antenna units are configured to placed at at least first and second locations, the arrangement being configured to execute at least two measurement cycles wherein during each measurement cycle the arrangement is configured to transmit at least one signal via antenna units one at a time and determine phase information for said signals being received by remaining antenna units. Distance variables determined based on the phase information are used to determine a change in distance between antenna units between measurement cycles.

Disclosed herein, in one aspect, is a system for determining depth within a borehole. The system can comprise a downhole device comprising at least one inertial sensor, at least one processor, and a memory in communication with the at least one processor. The memory can comprise instructions thereon that, when executed, cause the processor to: receive data from the at least one inertial sensor and store the data from the at least one inertial sensor in the memory with respective correlated time values. The system can further comprise a drill rig comprising at least one depth measurement device. The at least one depth measurement device can comprises a drill string position sensor that is configured to produce a measurement indicative of a length of a portion of a drill string removed from a borehole or a wireline sensor that is configured to determine a length of deployed wireline cable.

An electronic pallet (e-pallet) includes a superstructure mounted to a wheeled base platform. A tether device defines an articulation angle with respect to a leading edge of the superstructure, and is grasped by an operator towing the e-pallet. A motor connected to driven road wheels transmits a drive torque to the road wheels responsive to motor control signals, including a desired yaw rate and ground speed. A speed sensor, angle sensor, and length sensor are respectively configured to determine an actual ground speed of the e-pallet, the articulation angle, and a length of the tether device. An electronic controller, in response to the input signals, generates the motor control signals using proportional-integral-derivative (PID) control logic. Coupled lateral and longitudinal dynamics control loops respectively determine the desired yaw rate and ground speed to accommodate for motion of the operator.

A method is described to compute and display the line length required to troll a fishing rig at a desired depth. Line lengths and respective line angles measured at the surface are used to calculate an approximation to the actual underwater curve profile of the trolled fishing line, which is used to determine the line length required to troll at a desired depth or to determine the resulting depth for a specified line length. An embodiment is described which requires only a smartphone and software beyond standard trolling fishing equipment. This embodiment uses the embedded sensors of the smartphone to collect fishing line angle measurements. Also described is a method and devices to automatically collect the line angles and line lengths using a wireless fishing line inclinometer device and a wireless line counter, which is especially useful and convenient when software is implemented on a mounted marine electronics unit.

The present disclosure provides a displacement detection circuit of a maglev rotor system and a displacement self-sensing system thereof. The displacement detection circuit comprises a current sampling circuit (10) configured to collect a current flowing through a corresponding coil (4); coils (4), which are coils (4) distributed in series in the maglev rotor system; Hall sensors (20), the Hall sensors (20) being arranged in an upper auxiliary air gap (8) and a lower auxiliary air gap (8) of the maglev rotor system, and sensing surfaces of the Hall sensors (20) being perpendicular to magnetic field directions in the corresponding auxiliary air gaps (8); a Hall signal processing circuit (30) connected to the Hall sensors (20) and configured to differentiate a Hall sensing signal corresponding to the upper auxiliary air gap (8) and a Hall sensing signal corresponding to the lower auxiliary air gap (8); and a displacement signal resolving circuit (40) connected to the current sampling circuit (10) and the Hall signal processing circuit (30) respectively and configured to acquire a displacement of a rotor in the maglev rotor system according to the current and a differentiation result. By using the detection circuit and the displacement self-sensing system thereof, the axial size of the rotor is reduced, such that detection and control are coplanar, and high precision and simple design are realized.

The present disclosure provides a displacement detection circuit of a maglev rotor system and a displacement self-sensing system thereof. The displacement detection circuit comprises a current sampling circuit (10) configured to collect a current flowing through a corresponding coil (4); coils (4), which are coils (4) distributed in series in the maglev rotor system; Hall sensors (20), the Hall sensors (20) being arranged in an upper auxiliary air gap (8) and a lower auxiliary air gap (8) of the maglev rotor system, and sensing surfaces of the Hall sensors (20) being perpendicular to magnetic field directions in the corresponding auxiliary air gaps (8); a Hall signal processing circuit (30) connected to the Hall sensors (20) and configured to differentiate a Hall sensing signal corresponding to the upper auxiliary air gap (8) and a Hall sensing signal corresponding to the lower auxiliary air gap (8); and a displacement signal resolving circuit (40) connected to the current sampling circuit (10) and the Hall signal processing circuit (30) respectively and configured to acquire a displacement of a rotor in the maglev rotor system according to the current and a differentiation result. By using the detection circuit and the displacement self-sensing system thereof, the axial size of the rotor is reduced, such that detection and control are coplanar, and high precision and simple design are realized.