Abstract: An illustrative humidity sensor may include a substrate and a sensing field effect transistor. The sensing field effect transistor may comprise a source formed on the substrate, a drain formed on the substrate, a gate, and a piezoelectric layer disposed over the gate. Another illustrative humidity sensor may comprise a substrate, a semi-conductor layer disposed over the substrate, a piezoelectric layer disposed over the semi-conductor layer, a first electrode disposed on the piezoelectric layer, and a second electrode disposed on the piezoelectric layer. In some instances, the piezoelectric layer may comprise aluminum nitride.

Abstract: An electrochemical sensor comprises a substrate disposed within a housing, a plurality of electrodes disposed on a first surface of the substrate, an electrolyte disposed over at least a portion of each electrode of the plurality of electrodes, and a capillary disposed through the substrate. The capillary is configured to provide a diffusion pathway for a target gas to pass from an exterior of the housing to one or more of the plurality of electrodes.

Abstract: An illustrative humidity sensor may include a substrate and a sensing field effect transistor. The sensing field effect transistor may comprise a source formed on the substrate, a drain formed on the substrate, a gate, and a piezoelectric layer disposed over the gate. Another illustrative humidity sensor may comprise a substrate, a semi-conductor layer disposed over the substrate, a piezoelectric layer disposed over the semi-conductor layer, a first electrode disposed on the piezoelectric layer, and a second electrode disposed on the piezoelectric layer. In some instances, the piezoelectric layer may comprise aluminum nitride.

Abstract: A device includes a resonator having an oscillating portion with dimensions chosen to lead to a desired resonant frequency. A light source is positioned to provide light along the length of the oscillating portion at a specific wave length. A detector detects a change in oscillation of the resonator responsive to the wave pressure produced by the light source heating a gas. The light source is modulated with a frequency the same as the resonant frequency of the resonator.

Abstract: Embodiments of the present disclosure include devices and methods for humidity and temperature sensing. For example, in one embodiment, a sensing device can include a first surface acoustic wave (SAW) component, wherein the first SAW component is a temperature component, a second SAW component, wherein the second SAW component is a humidity component, a third SAW component, wherein the third SAW component is a reference component, and a piezoelectric layer, wherein the first SAW component, the second SAW component, and the third SAW component are on a surface of the piezoelectric layer.

Abstract: An example sensor that includes a first Schottky diode, a second Schottky diode and an integrated circuit. The sensor further includes a voltage generator that generates a first voltage across the first Schottky diode and a second voltage across the second Schottky diode. When the first Schottky diode and the second Schottky diode are subjected to different strain, the integrated circuit measures the values of the currents flowing through the first Schottky diode and the second Schottky diode to determine the strain on an element where the first Schottky diode and the second Schottky diode are attached.

Abstract: A method for photoacoustically sensing oxygen in a gaseous sample is disclosed, together with an apparatus for practicing the present method. Efficient and cost-effective oxygen sensing is provided by the use of a light source in the form of a light-emitting diode, which can be selected to correspond with the absorption spectra exhibited by oxygen in a gaseous sample. Filtering can be employed in order to control and narrow the wavelength of light emitted by the light source. An apparatus is disclosed which facilitates practice of the present method, including an arrangement by which ambient noise and vibration can be canceled.

Abstract: A system for detection of stress and deformation in a structural asset, for instance, one of reinforced concrete. An area on the asset may have a structure interface, such as a patch, attached to it with a fastening mechanism which may be a layer of an epoxy or other material, or be items such as screws, bolts, welds, or the like. One or more surface acoustic wave (SAW) strain sensors may be attached to the interface with an adhesive layer of epoxy or other material, or with mechanical items. Stress may be transmitted by the interface to the strain sensors. The sensors may be interrogated with a wire or wireless reader to obtain strain measurements. The measurements may indicate stress and deformations such as bulges and breaks in the asset. The measurements may also be a basis for determining location and extent of the stress and deformations.

Abstract: A device includes a resonator having an oscillating portion with dimensions chosen to lead to a desired resonant frequency. A light source is positioned to provide light along the length of the oscillating portion at a specific wave length. A detector detects a change in oscillation of the resonator responsive to the wave pressure produced by the light source heating a gas. The light source is modulated with a frequency the same as the resonant frequency of the resonator.

Abstract: A device includes a resonator having an oscillating portion with dimensions chosen to lead to a desired resonant frequency. A light source is positioned to provide light along the length of the oscillating portion at a specific wave length. A detector detects a change in oscillation of the resonator responsive to the wave pressure produced by the light source heating a gas. The light source is modulated with a frequency the same as the resonant frequency of the resonator.

Abstract: A device comprises a fuel line that carries a combustible fuel including gasoline, a first optical channel that evaluates a degree of absorption at a first wavelength spectrum of light transmitted through the combustible fuel within the fuel line, and a second optical channel that evaluates a degree of absorption at a second wavelength spectrum. The first and second wavelength spectrums consists of wavelengths of between about 800 nanometers (nm) and about 1200 nm. The device further comprises a controller configured to receive inputs from the first and second optical channels representing the degrees of absorption at the first and second wavelength spectrums, correlate the degrees of absorption with proportions of ethanol and water in the combustible fuel, and output data corresponding to the proportions of ethanol and water to a controller of a combustion engine fed with the combustible fuel.

Abstract: An example sensor that includes a first Schottky diode, a second Schottky diode and an integrated circuit. The sensor further includes a voltage generator that generates a first voltage across the first Schottky diode and a second voltage across the second Schottky diode. When the first Schottky diode and the second Schottky diode are subjected to different strain, the integrated circuit measures the values of the currents flowing through the first Schottky diode and the second Schottky diode to determine the strain on an element where the first Schottky diode and the second Schottky diode are attached.

Abstract: A system for detection of stress and deformation in a structural asset, for instance, one of reinforced concrete. An area on the asset may have a structure interface, such as a patch, attached to it with a fastening mechanism which may be a layer of an epoxy or other material, or be items such as screws, bolts, welds, or the like. One or more surface acoustic wave (SAW) strain sensors may be attached to the interface with an adhesive layer of epoxy or other material, or with mechanical items. Stress may be transmitted by the interface to the strain sensors. The sensors may be interrogated with a wire or wireless reader to obtain strain measurements. The measurements may indicate stress and deformations such as bulges and breaks in the asset. The measurements may also be a basis for determining location and extent of the stress and deformations.

Abstract: Embodiments of the present disclosure include devices and methods for humidity and temperature sensing. For example, in one embodiment, a sensing device can include a first surface acoustic wave (SAW) component, wherein the first SAW component is a temperature component, a second SAW component, wherein the second SAW component is a humidity component, a third SAW component, wherein the third SAW component is a reference component, and a piezoelectric layer, wherein the first SAW component, the second. SAW component, and the third SAW component are on a surface of the piezoelectric layer.

Abstract: A method includes forming multiple trenches in a first wafer, forming a sensor structure on a first surface of a second wafer, and bonding the first wafer and the second wafer. The method also includes etching a second surface of the second wafer to form a sensor diaphragm in the second wafer. The method further includes removing a portion of the first wafer by cutting the first wafer in multiple areas of the first wafer associated with the trenches. A sensor includes a substrate and a surface acoustic wave (SAW) resonator on a first surface of the substrate. The sensor also includes a bonding pad electrically coupled to the SAW resonator and a notch formed in a second surface of the substrate. The sensor further includes a cover separated from the first surface of the substrate by a spacer. The SAW resonator is located between the cover and the substrate.

Abstract: A SAW based sensor apparatus utilizing semi-synchronous SAW resonator having a single resonance at Bragg frequency with very high quality factor is disclosed. The semi-synchronous SAW resonator includes at least one inter-digital transducer, which generates and receives surface acoustic wave and a number of grating reflectors, which reflect the surface acoustic wave and generate a standing wave between the reflectors, The interdigital transducer and the grating reflectors can be fabricated on a substrate (e.g., quartz) by photolithographic process. The resonance condition is independent of transducer directivity and reflection coefficient per finger. Such a SAW based sensor apparatus having three semi-synchronous SAW resonators can be utilized for measuring pressure and temperature for a wireless tire-pressure monitoring system.

Abstract: A patterned dielectric elastomer actuator is disclosed which includes a series of thin parallel elastomer filaments, separated by certain distances sandwiched between a pair of rigid electrodes. The elastomer filaments and air acts as a patterned dielectric layer. The elastomer filaments can compress laterally from a circular cross-section to an elliptical shape when a voltage is applied between the rigid electrodes. The elastomer filaments can touch laterally, which implies no further squeezing in order to provide a minimal secure distance between the rigid electrodes. The dielectric elastomer actuator can be fabricated utilizing a reel-to-reel fabrication process with the thin elastomer filaments fabricated ahead of time, by extrusion techniques and cured completely before storing on reels.

Abstract: A solar cell includes an organic heterojunction having at least one donor material and at least one acceptor material. The solar cell also includes an inorganic heterojunction having multiple inorganic semiconductor materials. The organic heterojunction and the inorganic heterojunction could absorb light in different portions of a solar spectrum. For example, the organic heterojunction could absorb higher-energy photons, and the inorganic heterojunction could absorb lower-energy photons. The inorganic heterojunction could include a p-type inorganic semiconductor material having a bandgap between one and two electron-volts and an n-type inorganic semiconductor material having a bandgap greater than three electron-volts. An inorganic semiconductor layer could be placed between the organic heterojunction and the inorganic heterojunction. The inorganic semiconductor layer could be configured to collect holes generated by the organic heterojunction and to block electrons generated by the organic heterojunction.

Abstract: A patterned dielectric elastomer actuator is disclosed which includes a series of thin parallel elastomer filaments, separated by certain distances sandwiched between a pair of rigid electrodes. The elastomer filaments and air acts as a patterned dielectric layer. The elastomer filaments can compress laterally from a circular cross-section to an elliptical shape when a voltage is applied between the rigid electrodes. The elastomer filaments can touch laterally, which implies no further squeezing in order to provide a minimal secure distance between the rigid electrodes. The dielectric elastomer actuator can be fabricated utilizing a reel-to-reel fabrication process with the thin elastomer filaments fabricated ahead of time, by extrusion techniques and cured completely before storing on reels.

Abstract: A method includes forming multiple trenches in a first wafer, forming a sensor structure on a first surface of a second wafer, and bonding the first wafer and the second wafer. The method also includes etching a second surface of the second wafer to form a sensor diaphragm in the second wafer. The method further includes removing a portion of the first wafer by cutting the first wafer in multiple areas of the first wafer associated with the trenches. A sensor includes a substrate and a surface acoustic wave (SAW) resonator on a first surface of the substrate. The sensor also includes a bonding pad electrically coupled to the SAW resonator and a notch formed in a second surface of the substrate. The sensor further includes a cover separated from the first surface of the substrate by a spacer. The SAW resonator is located between the cover and the substrate.