A plastic scintillating fiber capable of detecting radiation having a weakly penetrating property is provided. A plastic scintillating fiber according to an aspect of the present invention includes a plastic optical fiber, and further includes a core containing at least one type of a fluorescent agent, a cladding layer having a refractive index lower than that of the core disposed at a center, and an outermost layer covering an outer peripheral surface of the cladding layer. The outermost layer contains a base material that generates scintillation light, and at least one type of a fluorescent agent that converts the scintillation light into light having a wavelength longer than that of the scintillation light.

A system for measuring pressure, temperature or both includes a diaphragm that responds to a change in temperature or pressure, and a base connected to the diaphragm that has a sapphire element. Between the diaphragm and the base is a cavity. An optical fiber that conducts light reflected off of a surface of the diaphragm is adjacent the cavity. An interrogator is used for detecting a deflection of the diaphragm based on at least two reflected light signals having similar wavelengths and coherence lengths. A quadrature phase detection unit demodulates signals received by the interrogator.

A multiplexed fiber optic sensor system including at least one light source, one or more first optical fibers having a first end arranged to receive light from the light source(s) and transmit the light to at least one fiber optic sensor, and one or more second optical fibers arranged to receive reflected light from the fiber optic sensors and transmit the reflected light to a light sensing element. Using the sensor system, it is possible to measure physical phenomena, such as electromagnetic phenomena, along multiple points along or within a material or structure of interest or on separate materials or structures. The fiber optic sensors can be electromagnetic phenomena sensors, pressure sensors, acceleration sensors, strain sensors, temperature sensors, or other sensors designed to measure physical phenomena. The sensor system can be used to measure phenomena of interest at several locations or take different kinds of measurements at the same or approximately the same location.

Fiber-optic equipment is often deployed in various locations, and performance of fiber-optic transmissions may be monitored as a gauge of equipment status to prevent costly and inconvenient communication outages. Events that damage equipment that eventually result in outage and may be desirable to address proactively, but the occurrence of such events may be difficult to detect only through equipment performance Presented herein are techniques for monitoring and maintaining fiber-optic equipment performance via enclosure sensors that measure physical properties within a fiber-optic equipment enclosure, such as temperature, pressure, light, motion, vibration, and moisture, which are often diagnostic and predictive of causes of eventual communication outages, such as temperature-induced cable loss (TICL), incomplete flash-testing during installation, exposure to hazardous environmental conditions, and tampering. An enclosure sensor package transmits the physical measurements to a monitoring station, and automatic determination of enclosure-related events may enable triaging and transmission of repair alerts to maintenance personnel.

A method for determining a location of a proppant in a subterranean formation includes obtaining a first set of data in a wellbore using a downhole tool. The proppant is pumped into the wellbore after the first set of data is obtained. The proppant is pumped while or after the subterranean formation is fractured. A second set of data is obtained in the wellbore using the downhole tool after the proppant is pumped into the wellbore. The first set of data and the second set of data include a gravitational field measurement. The first and second sets of data are compared, and in response to the comparison, the location of the proppant in the subterranean formation is determined.

A system for monitoring a condition of a pan line associated with a longwall mining system includes multiple pan segments arranged in a successive manner. Adjacently located pan segments are moveably coupled by an interconnecting joint. An underside of each pan segment defines an opening whose axis is parallel to a plane of the associated pan segment. The system also includes a fiber optic shape sensing system that has a fiber optic cable disposed along the multiple pan segments and located within the opening of each pan segment. A controller coupled to the fiber optic cable detects a shape of the fiber optic cable, identifies a position of each pan segment based on the detected shape of the fiber optic cable, and determines if a fault exists in the interconnecting joints between adjacently located pan segments based on the identified positions of respective ones of the adjacently located pan segments.

An optical displacement sensing system is provided. With configuration of an optical sensor disposed on a displacement platform and in cooperation with a broadband light source and an optical spectrum analyzer, when the displacement platform moves, the waveguide grating of the optical sensor is resonated and the reflected light provided with a resonance wavelength is formed. The waveguide grating has the plurality of grating periods, and when the displacement platform moves to a different position to make the broadband light source correspond to a different grating period, the position can correspond to the different resonance wavelength. Therefore, according to the aforementioned configuration, the position is determined according to the different resonance wavelength, instead of using an optical encoder; furthermore, the micrometer-scale or nanometer-scale displacement detection is achieved.

A fiber-optic sensors for measuring deformation, intended to operate in a harsh environment is provided. The sensor comprises a Fabry-Perot-cavity-based optical measurement head, a linking optical fiber and an expansion reserve case, the case comprising a segment of the linking optical fiber. The inside thickness of the case is comprised between one and several millimeters, the case being flat and of shape referred to as bicorne shape, the shape comprising a convex central portion and two concave symmetric ends, the optical fiber forming, inside the bicorne, one and only one arch, the segment of the optical fiber being, in addition, tangent to the internal surfaces of the reserve case, whatever the temperature conditions.

An apparatus is provided which comprises pressure pass-thru means, which includes: an optic fiber having a first end and a second end; a first connector coupled to the first end; a second connector coupled to the second end; a housing between the first and second ends, wherein the housing covers a portion of the optic fiber, wherein a portion of the optic fiber in the housing is bare; a filing material inside the housing; and a swaged gland fitting on the housing to secure the apparatus to a pressure boundary.

A corrosion monitoring system includes one or more objects coupled to respective portions of a transformer tank. The one or more objects are configured to corrode before the respective portions of the transformer tank. At least one optical sensor is coupled to each of the objects. The at least one optical sensor has an optical output that changes in response to strain of the object. An analyzer is coupled to the at least one optical sensor. The analyzer is configured to perform one or more of detecting and predicting corrosion of the transformer tank based on the output of the at least one optical sensor.