There is provided a method and system for identifying the location of an obstruction in a pipeline comprising: sensing the magnetic field generated by a pipeline at an initial pressure from a first location along the length of the pipeline to obtain a baseline reading; altering the pressure from a first end until a maximum pressure or minimum pressure is attained; sensing the magnetic field at the maximum or minimum pressure from the first location to obtain a stress reading; and identifying the location of the obstruction as a) being between a second end and the first location when there is a deviation between the stress reading and the baseline reading at the first location or as b) being between the first end and the first location when there is an absence of a deviation between the stress reading and the baseline reading at the first location.

There is provided a method and system for identifying the location of an obstruction in a pipeline comprising: sensing the magnetic field generated by a pipeline at an initial pressure from a first location along the length of the pipeline to obtain a baseline reading; altering the pressure from a first end until a maximum pressure or minimum pressure is attained; sensing the magnetic field at the maximum or minimum pressure from the first location to obtain a stress reading; and identifying the location of the obstruction as a) being between a second end and the first location when there is a deviation between the stress reading and the baseline reading at the first location or as b) being between the first end and the first location when there is an absence of a deviation between the stress reading and the baseline reading at the first location.

Encapsulation packages for stent-deployable monitoring devices formed of resonator sensors and allowing for magnetic biasing elements that exhibit a targeted impact on the mechanical characteristics of a stent are provided. Encapsulation packages are formed of different types and include a longitudinal shield and curved end on profile for aligning the shield within the deployable stent, the shield having perforations such that a resonator can be positioned adjacent the perforations for allowing particulate within the stent to collect and be measured by the resonator during deployment.

Encapsulation packages for stent-deployable monitoring devices formed of resonator sensors and allowing for magnetic biasing elements that exhibit a targeted impact on the mechanical characteristics of a stent are provided. Encapsulation packages are formed of different types and include a longitudinal shield and curved end on profile for aligning the shield within the deployable stent, the shield having perforations such that a resonator can be positioned adjacent the perforations for allowing particulate within the stent to collect and be measured by the resonator during deployment.

A method for stress-induced magnetic field signal acquisition and stress measurement is disclosed. The method can include the following steps: a1, conducting AC magnetization on a to-be-tested structure by using an AC magnetic field with preset frequencies and strengths, and acquiring the excitation magnetic field signals in at least one cycle; a2, subtracting the excitation magnetic field signals in at least one cycle of a stress-free sample having the same material as the to-be-tested structure from the excitation magnetic field signals acquired in step a1 to obtain a stress-induced magnetic field signals of the to-be-tested structure; a3, quantitatively assessing the stresses in the to-be-tested structure by comparing the mean values of the stress-induced magnetic field signals acquired in step a2 with the pre-calibrated relationship of stresses and the mean values of the stress-induced magnetic field signals for the material of the to-be-tested structure.

A method for stress-induced magnetic field signal acquisition and stress measurement is disclosed. The method can include the following steps: a1, conducting AC magnetization on a to-be-tested structure by using an AC magnetic field with preset frequencies and strengths, and acquiring the excitation magnetic field signals in at least one cycle; a2, subtracting the excitation magnetic field signals in at least one cycle of a stress-free sample having the same material as the to-be-tested structure from the excitation magnetic field signals acquired in step a1 to obtain a stress-induced magnetic field signals of the to-be-tested structure; a3, quantitatively assessing the stresses in the to-be-tested structure by comparing the mean values of the stress-induced magnetic field signals acquired in step a2 with the pre-calibrated relationship of stresses and the mean values of the stress-induced magnetic field signals for the material of the to-be-tested structure.

A stress distribution measurement device includes: a first magnetostrictive sensor and a second magnetostrictive sensor each including an excitation coil that excites AC magnetism in a measurement target using alternating current, and a detection coil to which alternating current is induced due to the AC magnetism flowing in the measurement target; an excitation circuit that applies a first excitation voltage to the excitation coil of the first magnetostrictive sensor and applies a second excitation voltage to the excitation coil of the second magnetostrictive sensor, the second excitation voltage having a phase or a waveform different from the first excitation voltage; and a detection circuit that includes a first detector that performs synchronous detection of current flowing in the detection coil of the first magnetostrictive sensor based on the first excitation voltage and a second detector that performs synchronous detection of current flowing in the detection coil of the second magnetostrictive sensor based on the second excitation voltage.

A hydrogen gas sensor utilizing electrically isolated tunneling magnetoresistive stress sensing elements is disclosed. The hydrogen gas sensor comprises: a deformable substrate, a magnetoresistive bridge stress sensor located on the deformable substrate, an electrical isolation layer covering the magnetoresistive bridge stress sensor, a magnetic shielding layer located on the electrical isolation layer, and a hydrogen sensing layer located above the deformable substrate. The hydrogen sensing layer is located in a plane perpendicular to the deformation of the substrate covering the electrical isolation layer. The hydrogen sensing layer is used for absorbing or desorbing hydrogen gas to generate expansion or contraction deformation and cause a stress change of the deformable substrate. The magnetoresistive bridge stress sensor is used for measuring a hydrogen gas concentration utilizing the stress change of the deformable substrate. It results in a hydrogen gas sensor with improved performance.

A magnetostrictive-type sensor temperature-detecting circuit configured to be used in a magnetostrictive-type sensor including an applied stress-detecting coil, and a driving section to output an alternating voltage, excite the coil with a resulting alternating electric current, and switch flow directions of the electric current flowing in the coil in response to switching voltage polarities of the output alternating voltage, to detect a temperature of the coil in the sensor. This temperature-detecting circuit includes an alternating electric current direction switching time-detecting section to detect an amount of time from when the voltage polarities of the output alternating voltage are switched until when the flow directions of the electric current flowing in the coil are switched, and a temperature-computing section to compute the temperature of the coil on the basis of the amount of time detected by the alternating electric current direction switching time-detecting section.

A magnetostrictive-type sensor temperature-detecting circuit configured to be used in a magnetostrictive-type sensor including an applied stress-detecting coil, and a driving section to output an alternating voltage, excite the coil with a resulting alternating electric current, and switch flow directions of the electric current flowing in the coil in response to switching voltage polarities of the output alternating voltage, to detect a temperature of the coil in the sensor. This temperature-detecting circuit includes an alternating electric current direction switching time-detecting section to detect an amount of time from when the voltage polarities of the output alternating voltage are switched until when the flow directions of the electric current flowing in the coil are switched, and a temperature-computing section to compute the temperature of the coil on the basis of the amount of time detected by the alternating electric current direction switching time-detecting section.