A temperature indicator includes a housing having a temperature detection assembly including a malleable substance. Switch circuitry having at least a portion thereof is disposed within the malleable substance. The malleable substance maintains the portion in a biased position. A communication module is coupled to the switch circuitry. Responsive to the temperature detection assembly being subjected to a temperature exceeding a threshold, the portion overcomes the biasing by the malleable substance such that the portion moves from the biased position relative to a conductive element that causes a change in a value output by the communication module when activated based on the portion either contacting the conductive element or disengaging from the conductive element.

A thermomagnetic sensor includes a thermomagnetic probe that includes a ferromagnetic material having a temperature-dependent magnetic permeability characterized by a maximum magnetic permeability value at a temperature below a Curie temperature of the ferromagnetic material. The thermomagnetic sensor further includes an alternating magnetic field source to produce an alternating magnetic field in a vicinity of the thermomagnetic probe to facilitate a measurement of the temperature-dependent magnetic permeability as function of temperature remotely using a thermomagnetic effect. A predetermined relationship between the temperature-dependent magnetic permeability and temperature in a range between the maximum magnetic permeability value and the Curie temperature provides a measurement of a temperature local to the thermomagnetic probe. A battery-temperature measurement system includes the thermomagnetic probe in a battery, a magnetic field coil to apply the alternating magnetic field, and a magnetic permeability measurement apparatus to measure the temperature-dependent magnetic permeability.

A thermomagnetic sensor includes a thermomagnetic probe that includes a ferromagnetic material having a temperature-dependent magnetic permeability characterized by a maximum magnetic permeability value at a temperature below a Curie temperature of the ferromagnetic material. The thermomagnetic sensor further includes an alternating magnetic field source to produce an alternating magnetic field in a vicinity of the thermomagnetic probe to facilitate a measurement of the temperature-dependent magnetic permeability as function of temperature remotely using a thermomagnetic effect. A predetermined relationship between the temperature-dependent magnetic permeability and temperature in a range between the maximum magnetic permeability value and the Curie temperature provides a measurement of a temperature local to the thermomagnetic probe. A battery-temperature measurement system includes the thermomagnetic probe in a battery, a magnetic field coil to apply the alternating magnetic field, and a magnetic permeability measurement apparatus to measure the temperature-dependent magnetic permeability.

In one example, the present disclosure describes a magnetic temperature sensor. For instance, in one example, an apparatus includes a first magnet, a magnetometer housing the first magnet, and a temperature converter coupled to the magnetometer. The first magnet includes a material having a magnetic field whose strength fluctuates in response to changes in temperature. The magnetic field induces an electric current in the magnetometer. The temperature converter then converts a measurement of the electric current to a corresponding measurement of temperature.

An apparatus for determining and/or monitoring temperature of a medium, comprising at least one temperature sensor and at least two reference elements for in situ calibration and/or validation of the temperature sensor, wherein the first reference element is composed at least partially of a first material, in the case of which at least one phase transition of at least second order occurs at least a first predetermined phase transition temperature in the temperature range relevant for calibration of the temperature sensor, wherein the second reference element is composed at least partially of a second material, in the case of which at least one phase transition of at least second order occurs at least a second predetermined phase transition temperature in the range relevant for calibration of the temperature sensor, and wherein the at least two reference elements are contacted via exactly two connection wires.

An apparatus for determining and/or monitoring temperature of a medium, comprising at least one temperature sensor and at least two reference elements for in situ calibration and/or validation of the temperature sensor, wherein the first reference element is composed at least partially of a first material, in the case of which at least one phase transition of at least second order occurs at least a first predetermined phase transition temperature in the temperature range relevant for calibration of the temperature sensor, wherein the second reference element is composed at least partially of a second material, in the case of which at least one phase transition of at least second order occurs at least a second predetermined phase transition temperature in the range relevant for calibration of the temperature sensor, and wherein the at least two reference elements are contacted via exactly two connection wires.

A wireless temperature sensor includes an electrical conductor and a material spaced apart from the conductor and located within one or more of the responding electric field and responding magnetic field of the conductor. The conductor is electrically unconnected and is shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the conductor resonates to generate harmonic electric and magnetic field responses, each of which has a frequency associated therewith. The material is selected such that it experiences changes in one of dielectric properties and magnetic permeability properties in the presence of a temperature change. Shifts from the sensor's baseline frequency response indicate that the material has experienced a temperature change.

A wireless temperature sensor includes an electrical conductor and a material spaced apart from the conductor and located within one or more of the responding electric field and responding magnetic field of the conductor. The conductor is electrically unconnected and is shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the conductor resonates to generate harmonic electric and magnetic field responses, each of which has a frequency associated therewith. The material is selected such that it experiences changes in one of dielectric properties and magnetic permeability properties in the presence of a temperature change. Shifts from the sensor's baseline frequency response indicate that the material has experienced a temperature change.

A magnetizable chemical composition including at least one polar solvent (4) selected from the group comprising an alcohol with a number of carbon atoms from C8 to C14, polytetrahydrofuran, or a mixture thereof; a ferromagnetic component, including a plurality of magnetizable particles (1) of Stable Single Domain (SSD) type selected from the group comprising magnetite, substituted magnetite and/or ferrite in an amount from 5 to 15% by volume of solvent and having a diameter from about 20 nm to 50 nm; and a polymer component (2) including polyvinyl butyral (PVB) or polyvinyl butyral-vinyl alcohol-vinyl acetate copolymer in a percentage from 3 to 15% by volume of solvent, the polymeric component being shaped as a net or mesh and delimiting a plurality of housing cells or zones (3), in each of which one of said particles (1) is housed immersed in the polar solvent (4). A method of obtaining such a composition, a microcapsule comprising the composition, an ink comprising the microcapsules and a method of testing a product marked with such ink.

A magnetizable chemical composition including at least one polar solvent (4) selected from the group comprising an alcohol with a number of carbon atoms from C8 to C14, polytetrahydrofuran, or a mixture thereof; a ferromagnetic component, including a plurality of magnetizable particles (1) of Stable Single Domain (SSD) type selected from the group comprising magnetite, substituted magnetite and/or ferrite in an amount from 5 to 15% by volume of solvent and having a diameter from about 20 nm to 50 nm; and a polymer component (2) including polyvinyl butyral (PVB) or polyvinyl butyral-vinyl alcohol-vinyl acetate copolymer in a percentage from 3 to 15% by volume of solvent, the polymeric component being shaped as a net or mesh and delimiting a plurality of housing cells or zones (3), in each of which one of said particles (1) is housed immersed in the polar solvent (4). A method of obtaining such a composition, a microcapsule comprising the composition, an ink comprising the microcapsules and a method of testing a product marked with such ink.