The present invention relates to a diaphragm for a pressure sensor, the diaphragm comprising a hybrid sol-gel film. The invention also extends to a process for the manufacture of said diaphragm for a pressure sensor and to a pressure sensor comprising said diaphragm.

The embankment monitoring system comprises an optic sensor chain (10) and an interrogator (20). The optic sensor chain (10) comprises a series of intrinsic fiber optic sensors (12) that are mutually spaced with respect to each other in a longitudinal direction of the optic sensor chain and at least one optic fiber (14) to optically connect the plurality of intrinsic fiber optic sensors to the interrogator. The interrogator is configured to issue an optic interrogation signal and the intrinsic fiber optic sensors are configured to respond to the optic interrogation signal with an optic measurement signal that is indicative for at least one physical parameter (P.sub.1) sensed by the intrinsic fiber optic sensors. The interrogator is further configured to process the optic measurement signals of the intrinsic fiber optic sensors to estimate a depth (d) as a function of a position (p) along said optic sensor chain (10).

The present invention relates to an optical gas detector for detecting a gas absorbing light at a known wavelength, wherein the gas detector comprises two essentially identical, parallel membranes defining a volume between them containing the gas to be investigated, and a modulated first light source emitting light at said known wavelength into said volume at a chosen frequency, the detector is adapted to detect relative movements between said membranes and said movements having a frequency corresponding to the rate or a multiple of the rate of said pulsed light source, and wherein the said volume has at least one opening allowing the gas to unrestricted flow or diffuse into said volume.

A transformer system includes a transformer and a transformer tank. The transformer tank houses the transformer in a bath of a dielectric fluid. The transformer system also includes a controller, and a fiber optic pressure sensor communicatively coupled to the controller. The fiber optic sensor is disposed in the dielectric fluid and operative to provide an output that varies with the pressure of the dielectric fluid. The controller is operative to determine the pressure of the dielectric fluid based on the output of the fiber optic pressure sensor.

Method for setting parameters for individual adaptation of an audio signal, including: performing a first listening test with the substeps: playing a plurality of first audio signals having different levels; obtaining feedback per frequency range from an individual which of the plurality of first acoustic signals is above an individual listening threshold; and using the lowest level of the different levels for which feedback is available as a level for the individual listening threshold per frequency range; performing adaptation of a second audio signal with the substeps: playing the second audio signal according to a total volume level considering a sound adaptation characteristic map; and varying the sound adaptation characteristic wherein the levels for the individual listening thresholds are used as minimum output levels in the sound adaptation characteristic map.

A sensor for measuring pressure, temperature or both may be provided. The sensor may include a diaphragm that may respond to a change in temperature or pressure, a base connected to the diaphragm, a cavity, and an optical fiber that may conduct light reflected off of a surface of the diaphragm. The diaphragm and base may be sapphire elements. An interrogator may be provided for detecting a deflection of the diaphragm.

An optical sensor having one or more sensing interference elements is disclosed. A first detector function generates a coarse optical path difference signal for example using a discrete Fourier transform of a detected interference spectrum, and a second detector function generates a refined optical path difference signal using the coarse optical path difference signal and for example a cross correlation of the interference spectrum with one or more sets of periodic transfer functions.

The embankment monitoring system comprises an optic sensor chain (10) and an interrogator (20). The optic sensor chain (10) comprises a series of intrinsic fiber optic sensors (12) that are mutually spaced with respect to each other in a longitudinal direction of the optic sensor chain and at least one optic fiber (14) to optically connect the plurality of intrinsic fiber optic sensors to the interrogator. The interrogator is configured to issue an optic interrogation signal and the intrinsic fiber optic sensors are configured to respond to the optic interrogation signal with an optic measurement signal that is indicative for at least one physical parameter (P.sub.1) sensed by the intrinsic fiber optic sensors. The interrogator is further configured to process the optic measurement signals of the intrinsic fiber optic sensors to estimate a depth (d) as a function of a position (p) along said optic sensor chain (10).

In some embodiments, apparatuses and methods are provided herein useful for sensing pressure. In some embodiments, miniature housings are manufactured at ends of optical fibers. In some embodiments, a diamond diaphragm is provided on a hollow housing that receives a fiber optic cable and is sealed to form a Fabry-Perot cavity. In some forms, a plurality of sensors may be manufactured in batch.

An example system includes a fuel tank, fittings mounted through a wall of the fuel tank, and optical sensors positioned within the fittings. A respective optical sensor includes a first pressure sensing end inserted through a fitting and internally into the fuel tank and a second end extending externally from the fuel tank. The system also includes an optical fiber bundle mounted external to the fuel tank, and having an optical fiber connected to each of the plurality of optical sensors for guiding light to each of the plurality of optical sensors.