An apparatus and method for the non-destructive determination of the content of the magnetizable and/or non-magnetizable portion of a sample, in which the sample is provided in an air gap of a magnetically conductive yoke, an alternating magnetic field is generated by an alternating magnetic field strength of an excitation coil in the yoke, and first measurement data relating to the sample are collected using a measuring device which is inductively coupled to the yoke, and comparing the first measurement data to second measurement data relating to a reference sample, wherein the same alternating magnetic field strength or the same alternating magnetic field is applied to both the reference sample and the sample and the difference between the two collected sets of measurement data is included as a measure in the determination of the content for the magnetizable and/or non-magnetizable content portion of the sample.

An apparatus and method for the non-destructive determination of the content of the magnetizable and/or non-magnetizable portion of a sample, in which the sample is provided in an air gap of a magnetically conductive yoke, an alternating magnetic field is generated by an alternating magnetic field strength of an excitation coil in the yoke, and first measurement data relating to the sample are collected using a measuring device which is inductively coupled to the yoke, and comparing the first measurement data to second measurement data relating to a reference sample, wherein the same alternating magnetic field strength or the same alternating magnetic field is applied to both the reference sample and the sample and the difference between the two collected sets of measurement data is included as a measure in the determination of the content for the magnetizable and/or non-magnetizable content portion of the sample.

Here is described an apparatus for measuring and/or monitoring a strength of a magnetic field inside a sample including: a fixing unit made of a non-magnetic material; a magnetic field strength measuring device having a sensor; and a first elongated member and a second elongated member. The elongated members are made of a material having a high relative magnetic permeability, and each of the elongated members has a first end portion and a second end portion. The fixing unit is configured to support the elongated members in a fixed posture such that the first end portion of the first elongated member and the first end portion of the second elongated member are positioned opposite to each other to form a gap, and the fixing unit is configured to support the sensor of the measuring device inside the gap or substantially inside the gap.

Here is described an apparatus for measuring and/or monitoring a strength of a magnetic field inside a sample including: a fixing unit made of a non-magnetic material; a magnetic field strength measuring device having a sensor; and a first elongated member and a second elongated member. The elongated members are made of a material having a high relative magnetic permeability, and each of the elongated members has a first end portion and a second end portion. The fixing unit is configured to support the elongated members in a fixed posture such that the first end portion of the first elongated member and the first end portion of the second elongated member are positioned opposite to each other to form a gap, and the fixing unit is configured to support the sensor of the measuring device inside the gap or substantially inside the gap.

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 method and system for estimating parameters of pipes. The method may comprise disposing an electromagnetic (EM) logging tool into a pipe string, creating a log from a first set of one or more measurements, and creating a synthetic model of one or more nested pipes based at least in part on a well plan. The method may further comprise adding a modeled pipe to the synthetic model, estimating one or more parameters of the modeled pipe through model calibration to form a calibrated model, and performing an inversion with the calibrated model to estimate one or more pipe parameters of the pipe string. The system may comprise an electromagnetic logging tool that may comprise a transmitter, wherein the transmitter is a first coil and is operable to transmit an electromagnetic field, and a receiver, wherein the receiver is a second coil and is operable to measure the electromagnetic field.

A method and system for estimating parameters of pipes. The method may comprise disposing an electromagnetic (EM) logging tool into a pipe string, creating a log from a first set of one or more measurements, and creating a synthetic model of one or more nested pipes based at least in part on a well plan. The method may further comprise adding a modeled pipe to the synthetic model, estimating one or more parameters of the modeled pipe through model calibration to form a calibrated model, and performing an inversion with the calibrated model to estimate one or more pipe parameters of the pipe string. The system may comprise an electromagnetic logging tool that may comprise a transmitter, wherein the transmitter is a first coil and is operable to transmit an electromagnetic field, and a receiver, wherein the receiver is a second coil and is operable to measure the electromagnetic field.

A magnetic property measuring apparatus measures magnetic properties of a magnetic recording medium, and includes a rotating mechanism which rotates the magnetic recording medium, a heating or cooling mechanism which heats or cools the magnetic recording medium; a temperature measuring mechanism which measures a temperature of the magnetic recording medium, a laser heating mechanism, disposed opposite to a measurement site of the magnetic recording medium, which heats the measurement site without making contact with the measurement site, a magnetic write part, disposed opposite to the measurement site, which magnetizes the measurement site without making contact with the measurement site, and a magnetic read part, disposed opposite to the measurement site, which reads a magnetic flux leakage at the measurement site without making contact with the measurement site.

A magnetic property measuring apparatus measures magnetic properties of a magnetic recording medium, and includes a rotating mechanism which rotates the magnetic recording medium, a heating or cooling mechanism which heats or cools the magnetic recording medium; a temperature measuring mechanism which measures a temperature of the magnetic recording medium, a laser heating mechanism, disposed opposite to a measurement site of the magnetic recording medium, which heats the measurement site without making contact with the measurement site, a magnetic write part, disposed opposite to the measurement site, which magnetizes the measurement site without making contact with the measurement site, and a magnetic read part, disposed opposite to the measurement site, which reads a magnetic flux leakage at the measurement site without making contact with the measurement site.