The present invention relates to a magnetometric device that measures the magnetic properties of a sample and whose most notable characteristic lies in that it is portable and highly precise, and can be used for the detection of a magnetic signal from nanostructures exposed to a fixed external magnetic field of excitation, of a unique value, it not being possible to alter the external magnetic field. The fixed external field can only be altered by modifying the device by means of exchanging the permanent magnets; however, once the device is sealed, this field does not vary. Different quantities of the same magnetic material may be placed in the sample holder, increasing the measurement signal; the present device can therefore determine the magnetic mass being measured following calibration of the magnetic material employed.

A method is provided for determining at least one material characteristic of a magnetizable metal body by means of a micromagnetic sensor arrangement, which comprises at least one excitation coil having a magnetic core for signal excitation and at least one receiver. The body is magnetized by the sensor arrangement via current or voltage excitation of the sensor arrangement, which comprises at least one sign change between a positive part of a half-wave and a negative part of a half-wave. At least one signal is measured in the receiver, and the signal is Fourier transformed. The material characteristic are determined from at least one Fourier component. The excitation is turned off, and the post-oscillation of the signal is measured in the receiver. At least the part of the signal resulting from the post-oscillation in the Fourier transformation is used.

Provided are methods of evaluating a sample for presence of an analyte using a magnetic sensor and a dissociation reagent. In some embodiments the sample is magnetically labelled and bound to the magnetic sensor, after which a dissociation reagent is introduced to dissociate the magnetic label from the magnetic sensor. The magnetic sensor can be used to detect the magnetically labeled analyte before and after introduction of the dissociation reagent, thereby allowing for evaluating of the presence of the analyte. Exemplary samples include aqueous solutions containing proteins, DNA, RNA, and other biologically relevant analytes. In some cases the methods provide for an increase in the speed at which the magnetic sensor can evaluate samples. Also provided are apparatuses and kits for performing the methods.

The invention relates to a system comprising superparamagnetic or anhysteretic nanoparticles (NPs) functionalised with an antibody, and a thin-film-type substrate of metal or an oxide thereof, functionalised with the same antibody; and to a method for detecting a biological analyte, such as a cell, protein, microorganism or similar, preferably a pathogenic microorganism, and even more preferably Listeria. The method comprises: (a) obtaining a control signal from a substrate (magnetic or not) coated with a thin film of metal or an oxide thereof, preferably gold, which can be functionalised with an antibody, the control signal being a magnetoresistance signal, a total magnetisation signal or a signal of the magnetisation curve; (b) mixing superparamagnetic or anhysteretic NPs functionalised with the antibody, with a liquid sample to analyse and confirm the presence or absence of the biological analyte, the NPs and the liquid sample making contact for 10-90 minutes; (c) dripping the dispersion obtained in step (b) onto the substrate of step (a), and then washing to remove NPs that are not chemically anchored to the surface of the biological analyte; (d) leaving the substrate to dry and re-measuring a signal in the same way as carried out in step (a); and (e) counteracting the control signal obtained in step (a) and the signal obtained in step (d), and in the absence of differences between the two measurements, confirming the absence of the biological analyte in the sample, the amount of microorganisms being directly proportional to the signal measured.

A magneto acoustic emission detection method for fatigue damage of ferromagnetic metal components: First, generating an excitation magnetic field by using a sine wave voltage signal, gradually increasing a loading voltage until a magneto acoustic emission signal of a bimodal envelope with an obvious tail peak is acquired, and taking a corresponding voltage peak value as a reference voltage; second, generating an excitation magnetic field by using a square wave voltage signal equal to or higher than a reference voltage, and acquiring a magneto acoustic emission signal with a T-shaped envelope; and third, calculating the average value of peak-to-peak values of the magneto acoustic emission signal in multiple periods to serve as a characteristic parameter, and enabling the characteristic parameter to have inflection point change along with the development of the initiation and expansion of the fatigue crack, and giving a timely early warning for the failure of the component. ##STR00001##

A material property determining system operable to determine properties of a conduit. The material property determining system includes a tool movable along a conduit and having at least one sensing device for sensing at least one property of the conduit. A processor is operable to process outputs of the at least one sensing device. Responsive to processing of the outputs by the processor, the processor correlates the processed outputs to determine the type of material of the conduit.

This disclosure provides systems, methods and apparatus for detecting foreign objects. In one aspect an apparatus for detecting a presence of an object is provided. The apparatus includes a resonant circuit having a resonant frequency. The resonant circuit includes a sense circuit including an electrically conductive structure. The apparatus further includes a coupling circuit coupled to the sense circuit. The apparatus further includes a detection circuit coupled to the sense circuit via the coupling circuit. The detection circuit is configured to detect the presence of the object in response to detecting a difference between a measured characteristic that depends on a frequency at which the resonant circuit is resonating and a corresponding characteristic that depends on the resonant frequency of the resonant circuit. The coupling circuit is configured to reduce a variation of the resonant frequency by the detection circuit in the absence of the object.

A magneto acoustic emission detection method for fatigue damage of ferromagnetic metal components: First, generating an excitation magnetic field by using a sine wave voltage signal, gradually increasing a loading voltage until a magneto acoustic emission signal of a bimodal envelope with an obvious tail peak is acquired, and taking a corresponding voltage peak value as a reference voltage; second, generating an excitation magnetic field by using a square wave voltage signal equal to or higher than a reference voltage, and acquiring a magneto acoustic emission signal with a T-shaped envelope; and third, calculating the average value of peak-to-peak values of the magneto acoustic emission signal in multiple periods to serve as a characteristic parameter, and enabling the characteristic parameter to have inflection point change along with the development of the initiation and expansion of the fatigue crack, and giving a timely early warning for the failure of the component.

The present disclosure discloses a safety pipe loop and method for strain monitoring of mountainous pipelines. The safety pipe loop may include a plurality of magnetic test detectors and a protective shell for protecting the plurality of magnetic test detectors. The number of the plurality of magnetic test detectors may be set to 4n, n is an integer number greater than or equal to 1. An angle between any two adjacent detectors of the plurality of magnetic test detectors may be 180°/2n. At least two of the plurality of magnetic test detectors may be connected in parallel through a data transmission line and output data through a data transmission interface. An outer layer of the protective shell may include non-magnetic hard alloy, and an inner layer of the protective shell may include non-metallic materials.

The invention relates to a method for observing a magnetic field of a material volume, in particular for determining properties of a workpiece under, in particular, magnetic, mechanical, thermal, and/or electrical excitation of a material volume of the workpiece, wherein the magnetic field of the material volume is sensed as a function of time and of frequency with high frequency resolution.