A system and method, as well as sub assemblies thereof, for detection of dielectric irregularities/inhomogeneities inside an object under study (OUS) be means of electromagnetic energy are disclosed. The system comprises a loop/cylinder emitter configured to be located close to the OUS with its axis of symmetry directed towards the OUS. A feeding line feeds the emitter with an alternating current at an operating frequency to cause a magnetic field therein, which in turn will induce a propagating electromagnetic field in the OUS. In order to reduce propagating fields outside of the OUS, the circumference of the emitter is smaller than the free-space wavelength corresponding to the operating frequency, and the feeding line has a characteristic impedance that is smaller than 20 Ohm.

To provide a surface characteristics evaluation method that evaluates the residual stress in a subject made of steel material subjected to a surface modification treatment. A surface characteristics evaluation method includes a step of preparing a surface characteristics evaluation apparatus, a step of placing the subject in such a manner that an alternating magnetic field induced by a coil of the surface characteristics evaluation apparatus permeates into the steel material, a step of generating an eddy current in the subject, a step of successively changing the alternating magnetic field applied to the coil, a step of calculating the impedance Z1 for each of different frequencies from the potential difference across the coil and the value of the current flowing through the coil, a step of performing computation based on the impedance Z1, and a step of evaluating the residual stress in the steel material based on the computation result.

A system for detecting disposal of metallic objects into an opening of a medical waste container, including: an indicator for indicating passage of metallic objects through the opening, a pair of receive coils and a transmit coil spaced therebetween shaped for receiving waste therethrough adjacent to the opening, and a controller in electrical communication with the coils. The controller generates and communicates a transmit signal to the transmit coil, which generates a magnetic field that induces voltage in each of the receive coils, which each generate a receive signal. The controller generates a waveform based on the receive signals with a baseline corresponding to absence of metallic objects, and analyzes the waveform with respect to opposite first and second thresholds. The controller activates the indicator in response to metallic objects passing through the coils when the waveform first exceeds the first threshold and then subsequently exceeds the second threshold.

A method for operating an inductive conductivity meter having a transmitting coil, a receiving coil and a terminating impedance device, the transmitting coil having a transmitting coil terminal, the receiving coil having a receiving coil terminal and the terminating impedance device having a terminating impedance, wherein the receiving coil is terminated with the terminating impedance device and wherein the transmitting coil and the receiving coil are inductively coupled with one another by an electrically conductive medium. To provide an improved accuracy of a determination of a conductivity of a medium a setpoint input impedance is specified, an input impedance is determined at the transmitting coil terminal, the terminating impedance is set such that the input impedance is matched to the setpoint input impedance, and a conductivity of the medium is determined using the adjusted input impedance and the set termination impedance.

The invention discloses methods and devices for rapidly detecting a biological and/or chemical residue in a liquid sample. In some embodiments of the instant invention, a single antenna is generally employed in proximity to an aqueous solution in a disposable cup, with electrical outputs being recorded by an electrical metering device in communication with the single antenna. Commercial plastic cups may be used for detection of electric fields related to cleanliness of water samples. General and specific target detection may be performed with various embodiments of the instant invention.

A method of and system for determining the total magnetic content of a fluid sample introduced within at least one coil. A sample withdrawal event time is determined and, at the sample withdrawal event time, the response of the at least one coil is analyzed in two zones, a first zone before the fluid sample withdrawal event time and a second zone after the fluid sample withdrawal event time. The total magnetic content of the fluid is calculated based on the difference in the response of the at least one coil in the first and second zones at the fluid sample withdrawal event time

A method is provided for inspecting a prestressed concrete pipe (PCP). An impedance probe is passed along the PCP. As the impedance probe travels along the PCP, a magnetic field within the impedance probe is generated and the impedance of the impedance probe is measured. The measured impedances are analyzed for anomalies, which may indicate broken prestressed wires. RFT probes, which are what are typically used for inspecting PCPs, require axial separation of two coils, one being an exciter coil and the other being a passive detector coil. However, there is only a single coil in an impedance probe and so the apparatus used to inspect the PCP is not as large axially. The apparatus used to inspect the PCP is simpler to set up than if an RFT probe is used, and coupling between a transmitter and a receiver is not a concern.

A wireless sensor includes at least one undulating electrical conductor. The undulating electrical conductor(s) extends along a spiral path between its first end and second end that remain electrically unconnected. Each undulating electrical conductor has inductance and capacitance wherein, in the presence of a time-varying magnetic field, the undulating electrical conductor(s) resonates to generate a harmonic response.

A metal detection apparatus (9) is tested with a test device (7) having at least one test article (79), movable through a detection zone (60). The test article is moved through the detection zone along a first transfer axis (ca) and a first input signal is measured. A first threshold (th1) is determined, where an amplitude of the first input signal exceeds the first threshold (th1). Then, an identical test article is moved through the detection zone along a further transfer axis (ta; . . . ) and a further input signal is measured and a further threshold (th2; . . . ) is determined, where an amplitude of the further input signal exceeds the further threshold (th2; . . . ). The first or further threshold (th1; th2; . . . ) is selected in the signal processing path (4) whenever the test article is moved along the related transfer axis (ca; ta; . . . ).

A system and method for monitoring a characteristic of a material by measuring electrical or magnetic properties of the material. The system includes a material monitoring device having at least one electrode and at least one magnetic coil, and is in communication with a machine learning model trained to recognize characteristics of the material based on electrical and magnetic properties of the material. The material can be stimulated with an electrical stimulus or stimulating magnetic field, and an electrical response signal or magnetic response signal can be measured. Applications to monitoring water quality, beverages, foodstuffs, and other characteristics of materials is discussed.