Abstract: A remote, noncontact temperature determination method and apparatus is provided, which is operable to determine the temperature of a conducting member in operative thermal communication with an object of interest. The method comprises the steps of first inducing a closed vortex eddy current in a conducting member by subjecting the member to a magnetic field, such that the corresponding eddy current magnitude changes exponentially over time. A characteristic time constant of the exponential current magnitude changes is then determined, and this is used to calculate the temperature of the object. The apparatus includes a field transmitting coil coupled with a waveform generator for inducing the eddy current, and a field receiving coil assembly which detects the corresponding induced magnetic. Temperature determinations can be made which are substantially independent of the relative distance and/or angular orientation between the conducting member and the field receiving coil assembly.

Abstract: A remote, noncontact temperature determination method and apparatus is provided, which is operable to determine the temperature of a conducting member in operative thermal communication with an object of interest. The method comprises the steps of first inducing a closed vortex eddy current in a conducting member by subjecting the member to a magnetic field, such that the corresponding eddy current magnitude changes exponentially over time. A characteristic time constant of the exponential current magnitude changes is then determined, and this is used to calculate the temperature of the object. The apparatus includes a field transmitting coil coupled with a waveform generator for inducing the eddy current, and a field receiving coil assembly which detects the corresponding induced magnetic. Temperature determinations can be made which are substantially independent of the relative distance and/or angular orientation between the conducting member and the field receiving coil assembly.

Abstract: A remote, noncontact temperature determination method and apparatus is provided, which is operable to determine the temperature of a conducting member forming a part of or in operative thermal communication with an object of interest. The method comprises the steps of first inducing a closed vortex eddy current (28) in a conducting member (16, 38, 44) by subjecting the member (16, 38, 44) to a magnetic field, such that the corresponding eddy current magnitude changes exponentially over time. A characteristic time constant of the exponential current magnitude changes is then determined, and this is used to calculate the temperature of the object. The apparatus (24) includes a field transmitting coil (14) coupled with a waveform generator (12) for inducing the eddy current (28), and a field receiving coil assembly (18) which detects the corresponding magnetic field induced by the eddy current (28).

Abstract: One-time, single-use sensor elements (22, 46) are provided for detecting the occurrence of predetermined conditions such as temperature and elapsed time-temperature. The sensor elements (22, 46) preferably comprise elongated, glass-coated, metal alloy, amorphous or nanocrystalline microwires (30, 48), which can be placed in a position to detect the predetermined condition of interest. An alternating magnetic field detector (28) may be used to continuously or periodically interrogate the sensor elements (22, 46) to determine if the predetermined condition has occurred. In one aspect of the invention, the microwires (30, 48) experience a change in configuration upon the occurrence of the predetermined condition, and have correspondingly different induced remagnetization responses.

Abstract: Improved microwire strain sensor elements (20, 40, 52, 62) and corresponding methods are provided, which permit accurate, wireless strain monitoring of a variety of structures, including composite structures, through use of a remote detector (28). The sensor elements (20, 40, 52, 62) have amorphous or nanocrystalline metallic alloy microwire cores (22, 48), which exhibit substantially reduced remagnetization responses when the sensor elements (20, 40, 52, 62) are coupled with a structure to be strain-monitored, and the structures are in an unstrained condition. When the monitored structure experiences a strain above a pre-selected threshold value, the microwire cores (22, 48) exhibit substantially different remagnetization responses as an indication that the monitored structure has experienced a strain above a strain threshold or over a range of strain.

Abstract: Improved, high-strength micro-thermocouples (10) are provided, which include first and second microwires (12, 14) each preferably in the form of an elongated metallic core (18, 22), with an outer glass coating (20, 24); at least one of the microwires (12, 14) is an amorphous microwire (12), and in preferred forms the other microwire is a crystalline microwire (14). The thermocouple junction (16) is formed by stripping the distal ends of the microwires (12, 14) to provide stripped ends (18a, 22a). The stripped crystalline microwire end (22a) is wrapped about the stripped amorphous microwire end (18a) to form a series of abutting convolutions (30). The micro-thermocouples (10) find particular utility in the fabrication and repair of carbon fiber composite materials, such as airplane components.

Abstract: A remote, noncontact temperature determination method and apparatus is provided, which is operable to determine the temperature of a conducting member forming a part of or in operative thermal communication with an object of interest. The method comprises the steps of first inducing a closed vortex eddy current (28) in a conducting member (16, 38, 44) by subjecting the member (16, 38, 44) to a magnetic field, such that the corresponding eddy current magnitude changes exponentially over time. A characteristic time constant of the exponential current magnitude changes is then determined, and this is used to calculate the temperature of the object. The apparatus (24) includes a field transmitting coil (14) coupled with a waveform generator (12) for inducing the eddy current (28), and a field receiving coil assembly (18) which detects the corresponding magnetic field induced by the eddy current (28).

Abstract: One-time, single-use sensor elements (22, 46) are provided for detecting the occurrence of predetermined conditions such as temperature and elapsed time-temperature. The sensor elements (22, 46) preferably comprise elongated, glass-coated, metal alloy, amorphous or nanocrystalline microwires (30, 48), which can be placed in a position to detect the predetermined condition of interest. An alternating magnetic field detector (28) may be used to continuously or periodically interrogate the sensor elements (22, 46) to determine if the predetermined condition has occurred. In one aspect of the invention, the microwires (30, 48) experience a change in configuration upon the occurrence of the predetermined condition, and have correspondingly different induced remagnetization responses.

Abstract: Improved microwire strain sensor elements (20, 40, 52, 62) and corresponding methods are provided, which permit accurate, wireless strain monitoring of a variety of structures, including composite structures, through use of a remote detector (28). The sensor elements (20, 40, 52, 62) have amorphous or nanocrystalline metallic alloy microwire cores (22, 48), which exhibit substantially reduced remagnetization responses when the sensor elements (20, 40, 52, 62) are coupled with a structure to be strain-monitored, and the structures are in an unstrained condition. When the monitored structure experiences a strain above a pre-selected threshold value, the microwire cores (22, 48) exhibit substantially different remagnetization responses as an indication that the monitored structure has experienced a strain above a strain threshold or over a range of strain.

Abstract: A method and system are presented for reading a magnetic tag (10), which is formed by an array of elongated magnetic elements arranged in a spaced-apart parallel relationship in accordance with a pattern of coded information. The tag (10) is located within an interrogating zone where an interrogating field is created. The interrogating field has an alternating traveling magnetic field (102) component with a space phase shift distribution along an axis perpendicular to a direction of force lines of the alternating traveling magnetic field component (102).

Abstract: A magnetic information-carrying tag is presented. The tag comprises a pair of spaced magnetic biasing elements magnetizable to create a magnetic field having a gradient within the space between the magnetic biasing elements, and an array of elongated magnetically soft elements accommodated in a spaced-apart substantially parallel relationship in the space between the magnetic biasing elements and defining a pattern indicative of the information carried in the tag.

Abstract: A magnetic tag is presented, as well as a method for manufacturing such a tag and a detector device and method for use in product authentication. The tag comprises a soft magnetic unit and a hard magnetic unit in its non-magnetized state both carried by a substrate. The soft magnetic unit includes at least one glass-coated amorphous microwire characterized by a large Barkhausen discontinuity and a zero or positive magnetostriction. The hard magnetic unit includes at least one strip-like element of a thickness substantially not exceeding a few tens of microns printed onto the substrate so as to extend along an axis parallel to the microwire. The hard magnetic material has coercivity substantially higher than 1000 Oe. The hard magnetic unit is thus such that, once magnetized, in order to be de-magnetized needs to be subjected to more than a single pulse of an alternating magnetic field of intensity varying from that of at least 250% of the coercive force value of the hard magnetic material to zero.

Abstract: A magnetic marker for use in an article surveillance system, and an electronic article surveillance system utilizing the same are presented. The marker comprises a magnetic element including a predetermined number of microwire pieces made of an amorphous metal-containing material coated with glass and having substantially zero magnetostriction, coercivity substantially less than 10 A/m, and permeability substantially higher than 20000, the predetermined number of the microwire pieces and a core diameter of the microwire piece being selected in accordance with a desired detection probability of the marker to be obtained in a specific detection system.

Abstract: A reading head is presented for use in a security system for reading an intermittent code pattern, when the code pattern is displaced in a reading direction with respect to the reading head. The code pattern is formed of a plurality of spaced-apart magnetic elements made. The reading head comprises a magnetic material producing a high-gradient static magnetic field, and a sensing element of a kind responsive to signals produced by the magnetic elements. The magnetic material is designed such that it defines an extended narrow region where the static magnetic field vector is substantially equal to zero. The sensing element is located substantially within the zero-field region, and is thereby responsive to signals generated by each of the magnetic elements, when the magnetic element is located in the zero-field region.

Abstract: A magnetic marker for use in an article surveillance system, and an electronic article surveillance system utilizing the same are presented. The marker comprises a magnetic element including a predetermined number of microwire pieces made of an amorphous metal-containing material coated with glass and having substantially zero magnetostriction, coercivity substantially less than 10 A/m, and permeability substantially higher than 20000, said predetermined number of the microwire pieces and a core diameter of the microwire piece being selected in accordance with a desired detection probability of the marker to be obtained in a specific detection system.

Abstract: A magnetic microwire for use in a magnetic tag attachable to a product is provided to enable authentication of the product, as well as the magnetic tag, a detector device and a system for product authentication utilizing the same. The magnetic microwire is a glass-coated amorphous magnetic microwire characterized by a large Barkhausen discontinuity and substantially zero or positive magnetostriction. The microwire is responsive to an external alternating magnetic field generated by the detector device to produce short pulses of magnetic field perturbations.

Abstract: A magnetic marker for use in an article surveillance system, and an electronic article surveillance system utilizing the same are presented. The marker comprises a magnetic element formed by at least one microwire piece made of an amorphous metal-containing material coated with glass. The microwire piece has substantially zero magnetostriction, coercivity substantially less than 10 A/m, and permeability substantially higher than 20000.

Abstract: A magnetic microwire for use in a magnetic tag attachable to a product is provided to enable authentication of the product, as well as the magnetic tag, a detector device and a system for product authentication utilizing the same. The magnetic microwire is a glass-coated amorphous magnetic microwire characterized by a large Barkhausen discontinuity and substantially zero or positive magnetostriction. The microwire is responsive to an external alternating magnetic field generated by the detector device to produce short pulses of magnetic field perturbations.

Abstract: A filter for wires and cables comprising at least one pair of inner conductive wires made of an electrically conductive metal covered with an outer layer of magnetic absorbing material. This outer layer is formed from glass-coated microwires containing soft ferromagnetic amorphous material, preferably wound about the conductive wires to form a thin ferromagnetic layer. The filter may include two or more pairs of inner conductors with the ferromagnetic outer layers implemented separately or as a single common outer layer. The inner pairs of conductors may be either straight or twisted.

Abstract: A heating pipe including a substantially tubular, electrically insulative inner element configured to allow flow of a liquid therethrough. An electric heating element in the form of a substantially flat ribbon of overheated amorphous metallic alloy is wound in a substantially helical pattern around the inner element. The helical pattern defines adjacent, electrically insulated windings. The inner element electrically insulates the heating element from liquid in the inner element. An electrically insulative outer element is provided for electrically and thermally insulating the heating element from the surrounding ambient environment.