A system for detection of stress and deformation in a structural asset, for instance, one of reinforced concrete. An area on the asset may have a structure interface, such as a patch, attached to it with a fastening mechanism which may be a layer of an epoxy or other material, or be items such as screws, bolts, welds, or the like. One or more surface acoustic wave (SAW) strain sensors may be attached to the interface with an adhesive layer of epoxy or other material, or with mechanical items. Stress may be transmitted by the interface to the strain sensors. The sensors may be interrogated with a wire or wireless reader to obtain strain measurements. The measurements may indicate stress and deformations such as bulges and breaks in the asset. The measurements may also be a basis for determining location and extent of the stress and deformations.

System for monitoring structural assets

A magnetic field sensing apparatus including a magnetic flux concentrator and a plurality of magnetoresistance units is provided. The magnetic flux concentrator has a top surface, a bottom surface opposite to the top surface, and a plurality of side surfaces connecting the top surface and the bottom surface. The magnetoresistance units are respectively disposed beside the side surfaces. The magnetoresistance units are electrically connected to form at least one kind of Wheatstone full bridge in three different periods, so as to measure magnetic field components in three different directions, respectively, and to cause the at least one kind of Wheatstone full bridge to output three signals corresponding to the magnetic field components in the three different directions, respectively.

Magnetic field sensing apparatus

Techniques are described for sensing a position of an object located within an enclosure over a position range. The techniques include generating an expected output signal of each of a plurality of magnetic field sensors disposed along an outer surface of the enclosure, receiving actual output signals from the sensors, wherein each actual output signal indicates a relative proximity of a magnetic target coupled to the object to the corresponding sensor. The techniques further include superimposing the expected output signal over the actual output signals, and iteratively shifting the expected output signal over position relative to the actual output signals and comparing the shifted expected output signal to the actual output signals, until the expected output signal compared to the actual output signals corresponds to a substantially minimized error parameter. The position of the object may then be determined based at least in part on the shifted expected output signal.

Techniques for calibrating a linear position sensor

A current sensor comprises a sensor bridge, with magnetic tunnel junction (MTJ) elements, a MTJ temperature compensation resistor, and a current lead integrated onto a chip. The current lead is positioned close to the sensor bridge, and it is used to carry the test current. A permanent magnet is arranged at the periphery of the MTJ temperature compensation resistor. The permanent magnet rigidly aligns the magnetization direction of the free layer of the MTJ temperature compensation resistor anti-parallel to the magnetization direction of a pinning layer. The sensor bridge is connected in series with the MTJ temperature compensation resistor to temperature compensate the sensor bridge. A magnetic field generated by the test current produces an output voltage at the output of the temperature compensated sensor bridge that is proportional to the test current value.

Current sensor with temperature-compensated magnetic tunnel junction bridge

Die Erfindung betrifft einen Schmierstoffverteiler (10), umfassend mindestens ein Verteilerelement (13) mit einem Dosierkolben (14), der in dem Verteilerelement (13) bewegbar ist, wobei ein Magnetsensor (20) derart an dem Verteilerelement (13) angebracht ist, dass die Position des Dosierkolbens (14) in mindestens einer Position detektierbar ist, wobei der Magnetsensor (20) die Position des Dosierkolbens (14) unter Ausnutzung eines magnetoresistiven Effekts, insbesondere des Riesenmagnetowiderstands (GMR), oder des anisotropen Magnetowiderstands (AMR) oder des Tunnel-Magnetowiderstands (TMR) oder des ausergewohnlichen Magnetowiderstands (EMR) oder des planaren Hall-Effekts detektiert.

Schmierstoffverteiler mit magnetoresistivem Sensor und Verfahren zur Überwachung eines Schmierstoffverteilers

In one example, a position sensor is provided. The position sensor comprises an integrated circuit, and a magnetic field sensor that provides a detected signal indicative of a position of a magnetic field source to the integrated circuit. The magnetic field sensor comprises a tunneling magnetoresistance (TMR) sensor. The position sensor further comprises a wireless circuit coupled to the integrated circuit, wherein the wireless circuit comprises an antenna configured to radiate a position signal based on the detected signal.

Wireless magnetic position sensor

A magnetic sensor that includes a magnetic film deposited on a surface acoustic wave device. The surface acoustic wave device includes an input interdigital transducer and an output interdigital transducer. An RF voltage can be applied at the input interdigital transducer in order to generate acoustic waves, which can travel via the magnetic material to the output interdigital transducer. The application of an external magnetic field alters the conductivity of the magnetic material. Such a change in conductivity attenuates the velocity of the traveling surface acoustic wave and an output frequency due to electro acoustic interaction. The change in the applied magnetic field can be indirectly monitored as a change in output frequency of the SAW device at the output interdigital transducer.

Sankaranarayanan Kalathil

Papers

Wireless magnetic position sensor

Magnetic surface acoustic wave sensor apparatus and method