Abstrac t This paper presents a measuring system capable of detecting longitudinal and circumferential defects using remote field eddy current in stainless steel tubes with an AMR sensor. An excitation coil is required with a time varying current to produce a magnetic field that penetrates the material on test. The experimental results from both defects are compared with other results for the s...

The tensile force of pre-stressed concrete (PSC) girders is the most important factor for managing the stability of PSC bridges. The tensile force is induced using pre-stressing (PS) tendons of a PSC girder. Because the PS tendons are located inside of the PSC girder, the tensile force cannot be measured after construction using conventional NDT (non-destructive testing) methods. To monitor the...

Implantable biosensors were developed for real-time monitoring of pressure and strain in the human body. The sensor, which was wireless and passive, consisted of a soft magnetic material and a permanent magnet. When exposed to a low frequency AC magnetic field, the soft magnetic material generated secondary magnetic fields that also included the higher-order harmonic modes. Parameters of intere...

A new type of MEMS sensor has been developed for measuring AC electric current. The sensor is comprised of a piezoelectric aluminum nitride MEMS cantilever with a microscale composite permanent magnet mounted to its free end. When placed in proximity to a wire carrying AC current, the alternating magnetic field surrounding the wire induces a sinusoidal force on the sensor magnet, deflecting the...

Cell-based sensing represents a new paradigm for performing direct and accurate detection of cell- or tissue-specific responses by incorporating living cells or tissues as an integral part of a sensor. Here we report a new magnetic cell-based sensing platform by combining magnetic sensors implemented in the complementary metal-oxide-semiconductor (CMOS) integrated microelectronics process with ...

Northern wheatearssmall migratory songbirds that weigh about the same as an AA batteryfly 30,000 km every year from Alaska via Asia to Kenya and back again. Their ability to do so depends crucially on having an internal magnetic compass with which to sense the Earth’s magnetic field. It appears that all avian migrants have such a light-dependent compass. Although it is clear that the primary ...

Arrays of micron-sized magnetic sensors and sensor spacing on a single chip can be used to detect very small magnetic fields with high spatial resolution. These very small magnetic fields, or changes in magnetic fields, are associated with magnetic biosensors, non-destructive test/ inspection/evaluation, document validation including currency and credit cards and magnetic imaging. By using a si...

In this article, the free vibration analysis of magneto-electro-elastic (MEE) Timoshenko micro beam model based on surface stress effect and modified strain gradient theory (MSGT) under moving nano-particle is presented. The governing equations of motion using Hamilton’s principle are derived and these equations are solved using differential quadrature method (DQM). The effects of dimensionless...

A multichannel imaging system is presented, consisting of 25 microfabricated optically-pumped magnetometers. The sensor probes have a footprint of less than 1 cm2 and a sensitive volume of 1.5 mm × 1.5 mm × 1.5 mm and connect to a control unit through optical fibers of length 5 m. Operating at very low ambient magnetic fields, the sensor array has an average magnetic sensitivity of 2...