A biomedical pressure sensor for measuring the pressure in a fluid includes an optical fiber having at least one measurement section arranged at a distance from a distal end of the optical fiber. The biomedical pressure sensor further includes a deforming member on the outer surface of the optical fiber at the location of the measurement section that is arranged for locally deforming the optical fiber under the influence of the applied pressure of the fluid to be measured. The measurement section is arranged for measuring said local deformation of the optical fiber.

A method for measuring pressure of a gaseous fuel compressed in a feed system of an engine equipping a motor vehicle, by a pressure measuring device having an infrared quality sensor and an electronic control unit, the measuring method being characterized in that it consists in determining a corrected absorbance value of the fuel based on absorbance measurements performed by infrared analysis, at preset wavelengths, and in comparing the value to a nominal absorbance value, determined beforehand based on absorbance measurements performed at a nominal pressure after a pressure stabilization phase of the fuel and at the same said wavelengths, in order to determine the fuel pressure.

A method for measuring pressure of a gaseous fuel compressed in a feed system of an engine equipping a motor vehicle, by a pressure measuring device having an infrared quality sensor and an electronic control unit, the measuring method being characterized in that it consists in determining a corrected absorbance value of the fuel based on absorbance measurements performed by infrared analysis, at preset wavelengths, and in comparing the value to a nominal absorbance value, determined beforehand based on absorbance measurements performed at a nominal pressure after a pressure stabilization phase of the fuel and at the same said wavelengths, in order to determine the fuel pressure.

The present technology includes a color changeable indicator that changes color upon exposure of the indicator to high pressure and comprises at least one reagent releasing layer, a transition layer disposed on the reagent releasing layer, a color changeable layer disposed on the transition layer, and a non-porous protectant encompassing the reagent releasing layer, the transition layer and the color changeable layer. An additional reagent releasing layer can be located between the transition layer and the color changeable layer. The indicators provide simple, reliable, and cost effective detection means for detecting whether a product has been exposed to high pressure, e.g. high pressure pasteurization, and may find use in applications such as food and beverage processing and/or packaging and medical applications.

Systems, methods, and apparatuses for taking pressure measurements are provided. A multi-hole pressure sensor probe can include a probe tip having a plurality of probe tip holes. The probe tip holes can lead to probe tip channels that convey fluid from the measurement environment to pressure transducers. The pressure transducers can operate using optical transduction techniques. A light source can be applied to the diaphragm, and the light reflected from the diaphragm changes as the position of the diaphragm changes. Further, a reflective material can be applied on the backside of the diaphragm to increase its reflective properties. The light can then be collected and analyzed using a photodiode to determine the environmental pressure acting on the different holes of the probe.

A method for forming a pressure sensor is provided wherein an optical fibre is provided, the optical fibre comprising a core, a cladding surrounding the core, and a birefringence structure for inducing birefringence in the core. The birefringence structure comprises first and second holes enclosed within the cladding and extending parallel to the core. A portion of the optical fibre comprising the core and the birefringence structure is encased within a chamber, wherein the chamber is defined by a housing comprising a pressure transfer element for equalising pressure between the inside and the outside of the housing. An optical sensor is provided along the core of the optical fibre. Providing the optical sensor comprises optically inducing stress in the core so that the optical sensor exhibits intrinsic birefringence. The chamber is filled with a substantially non-compressible fluid. Consequently, the birefringence structure is shaped so as to convert an external pressure provided by the non-compressible fluid within the chamber to an anisotropic stress in the optical sensor.

A passive microscopic Fabry-Pérot Interferometer (FPI) pressure sensor includes an optical fiber and a three-dimensional microscopic optical enclosure. The three-dimensional microscopic optical enclosure includes tubular side walls having lateral pleated corrugations and attached to a cleaved tip of the optical fiber to receive a light signal. An optically reflecting end wall is distally engaged to the tubular side walls to enclose a trapped quantity of gas that longitudinally positions the optically reflecting end wall in relation to ambient air pressure, changing a distance traveled by a light signal reflected back through the optical fiber.

A pressure sensor and a pressure detecting method are provided, the pressure sensor includes a liquid crystal cell including a cholesteric liquid crystal layer, a liquid crystal state detector module and a pressure finder module, and the liquid crystal cell includes a pressure receiving surface. The liquid crystal state detector module is configured to detect a liquid crystal arrangement state in the cholesteric liquid crystal layer in a situation where a pressure is applied on the pressure receiving surface of the liquid crystal cell; the pressure finder module is configured to find a value of the pressure corresponding to the liquid crystal arrangement state from a pre-stored correspondence table.

A pressure sensor and a pressure detecting method are provided, the pressure sensor includes a liquid crystal cell including a cholesteric liquid crystal layer, a liquid crystal state detector module and a pressure finder module, and the liquid crystal cell includes a pressure receiving surface. The liquid crystal state detector module is configured to detect a liquid crystal arrangement state in the cholesteric liquid crystal layer in a situation where a pressure is applied on the pressure receiving surface of the liquid crystal cell; the pressure finder module is configured to find a value of the pressure corresponding to the liquid crystal arrangement state from a pre-stored correspondence table.

A long-term in-situ observation device for the deep sea bottom supported engineering geological environment is provided, including: a sediment acoustic probe, a sediment pore water pressure probe, a three-dimensional resistivity probe, a water observation instrument, a long-term observation power supply system, a probe hydraulic penetration system, a general control and data storage transmission system, an acoustic releaser, an underwater acoustic communication apparatus, and an instrument platform. The observations include the engineering properties, physical properties, mechanical properties, and biochemical properties of a seawater-seabed interface-sediment. The engineering properties and the physical and mechanical indexes of seafloor sediments are comprehensively determined by three-dimensional measurement of seafloor resistivity and acoustic wave measurements. The physical and biochemical properties of seawater are expected to be acquired by sensors. The observation probe penetrates into the sediments following the hydraulic method. Powered by seawater dissolved oxygen batteries; data transmission is achieved through sea surface relay buoys and satellite communications. The present invention provides an effective integrated, in situ and long-term observation device and method for the deep sea engineering geological environment.