Abstract: A physical quantity measuring system according to the present invention comprises: an optical fiber having fiber Bragg gratings; a light source connected to the optical fiber; an arrayed waveguide grating connected between the light source and the optical fiber via an optical branching filter, and having output channels of which central wavelengths of at least three output channels are included in a one-tenth loss band of a reflected light by the fiber Bragg grating; light receiving devices for receiving light output from the output channels on a one-to-one basis; and a central reflected wavelength change detecting unit connected to the light receiving devices for estimating a change in a central reflected wavelength based on a physical quantity, by calculating first and second group signals from light receiving signals corresponding to the at least three output channels, and by calculating a differential signal between the first and the second group signals.

Abstract: A load monitoring system for wind turbine blades utilizes optical fibre strain sensors (5) moulded into the turbine blades. A sensor monitoring instrument is located in the hub (3) of the turbine. Various arrangements of cabling are disclosed to maximize fault tolerance. Various arrangements of a temperature compensation device for the strain sensors is also disclosed. The strain sensors (5) and optical fibre (7) may be provided on a pre-cured patch (9) for incorporation in the structure of the turbine blade. Furthermore, it is disclosed that each blade comprises an optical fibre strain sensor and a cable to connect the sensors to processing equipment, wherein each such cable includes a connector at each end whereby each blade can be replaced independently. Also, it is shown to provide an output connector for connecting the sensor to processing equipment in a cavity that is filled with a material for inhibiting free movement of the output connector.

Abstract: A wind turbine blade (1) incorporating an optical fibre (4) configured for structural monitoring of the turbine blade. The optical fibre comprises at least one strain sensor (5). One end of the optical fibre (4) is an output point, which is connected to a data processing device (3) configured to process signals from the strain sensor (5). The other end of the optical fibre is an alternative output point, which is also connectable to the data processing device, such that in the event of a breakage in the optical fibre, signals from the strain sensor are available from at least one of the output points.

Abstract: The present invention provides an evaluation method for evaluating whether a light-emitting element material to be evaluated is suitable for a host material or a guest material. By carrying out a first step of measuring absorption intensity of a light-emitting element material and a second step of irradiating the light-emitting element material with light for a predetermined period of time, repeatedly; thereby a change in absorption intensity with time is evaluated so that whether the light-emitting material is suitable for a host material or a guest material can be distinguished. The light emitted to the light-emitting element material preferably has a wavelength component which is absorbed by a skeleton which contributes to excitation of the light-emitting element material.

Abstract: By performing optical measurements and evaluating the optical response of an appropriately prepared measurement site, stress-related characteristics, such as intrinsic stress of dielectric layers, may be evaluated due to the dependency of the optical response on stress-induced modifications of the charge carrier mobility of a conductive layer provided below the dielectric layer probed by an optical signal. Consequently, inline measurement results may be obtained in a highly efficient manner, thereby providing the potential for monitoring complex stress engineering strategies during a manufacturing sequence for forming microstructure devices.

Abstract: Methods and apparatus for predicting service life of remote equipment for infiltration of liquid are disclosed. Such methods and apparatus preferably include at least one fiber optic sensor assembly adapted to react after being exposed to a predetermined quantity of liquid.

Abstract: A method and system for measuring radial strain on powder or other granular material while the powder is subject to compressive axial and radial loading. The powder is contained within a pliable sleeve. As pressure is applied to the powder, the sleeve changes diameter. An optical emitter emits a beam of light, which is intersected by the entire diameter of the sleeve. An optical sensor receives the intersected beam, and generates a response signal that indicates the diameter of the sleeve. This change in diameter can be related to a constitutive property such as strain.

Abstract: A curvature sensing device 10 comprising, a first fibre Bragg grating (FBG) strain sensor 12, a second FBG strain sensor 14, a flexible piece comprising two end pieces 16, 18 joined by a tubular mid-section 20. The device 10 further comprises 16 contact rollers 22 provided on the internal surfaces of the end pieces 16, 18, which maintain the end pieces 16, 18 tangential to a pipe around which the device 10 is located. The FBG strain sensors 12, 14 are embedded within the mid-section 20 and are arranged in two generally orthogonal planes, so that the curvature is measured in two dimensions. This enables the device 10 to detect both the magnitude and direction of bending/curvature within a pipe. Bending in a pipe is transferred through the end pieces 16, 18 to the mid-section 20. The FBG sensors 12, 14 measure bending of the mid-section 20 from which bending of the pipe can be inferred.

Abstract: A method and a device for contactless determination of forces and/or moments acting on a hollow cylindrical body (12), in which via a light source (20; 38; 40), light radiation is produced within the hollow cylindrical body (12); measurement signals are recorded by an optoelectronic sensor (22; 34); the measurement signals recorded by the optoelectronic sensor (22; 34) are supplied to the signal processing unit (26); the signal processing unit (26) detects and outputs changes of the measurement signals relative to an initial state determined beforehand by calibration, corresponding to the initial undeformed state of the hollow cylindrical body (12); and when a mechanical deformation of the hollow cylindrical body (12) is present, according to a calibration function or a calculation rule, the signal processing unit (26) outputs an output signal that describes the forces and/or moments that are causing the mechanical deformation of the hollow cylindrical body (12).

Abstract: An optical tactile sensor has a touch pad and a CCD camera for imaging behavior of the touch pad. A CPU processes image information from the CCD camera, extracts information on the size, shape, and center of gravity of a contact region, and extracts information on the size of a fixation region. The CPU obtains a normal force from the size of the contact region, obtains a tangential force from the shape of the contact region and the center of gravity of the contact region, and obtains a friction coefficient from the ratio of the size of the fixation region to the size of the contact region.

Abstract: An image pickup device disposed in a predetermined position relative to a surface of a strained silicon wafer photographs the surface of the strained silicon wafer in a plurality of rotation angle positions on photographing conditions under which bright lines appearing on the surface of the strained silicon wafer can be photographed, in an environment where a light source device illuminates the surface of the strained silicon wafer which is rotating. A composite image in a predetermined angle position is generated from surface images of the strained silicon wafer in a plurality of rotation angle positions obtained by the image pickup device.

Abstract: A method of detecting deformation in a substrate includes detecting one or more changes in one or more emission characteristics of at least one pair of plasmon-coupled nanoparticles associated with a substrate, where the substrate includes at least one pair of plasmon-coupled nanoparticles. An apparatus for deformation detection includes a detection unit for detecting one or more changes in one or more emission characteristics of at least one pair of plasmon-coupled nanoparticles associated with a substrate.

Abstract: A system and method for monitoring the vibrations of a machine that includes a reflective patch affixed to the machine and a vibration detection unit including an optics module. The optics module may be positioned remotely from the machine such that the optics module transmits an electromagnetic beam to the reflective patch and reflected from the reflective patch to the optics module. The optics module demodulates the electromagnetic beam to determine the vibration of the machine.

Abstract: A method includes rotating a rotor, measuring a rotor rotational time for the rotor to complete a revolution, determining a blade interval by dividing the rotor rotational time by a number of blades carried on the rotor, establishing an active hold-off time interval as a percentage of the blade interval time, directing a beam of light at the blades of the rotor using a laser, sensing light reflected from the blades, generating an output signal as a function of the sensed light, establishing a signal amplitude threshold, analyzing an amplitude of the output signal to trigger the active hold-off time interval when the amplitude reaches the signal amplitude threshold, and generating a blade arrival signal as a function of triggered active hold-off time intervals. The output signal is not analyzed within each active hold-off time interval.

Abstract: A system and associated method permit remote monitoring of subsurface structure for purposes of early detection and location of hidden anomalies, e.g., water seepage in levees. Anomalies may be due to sand boils or displacement of underlying soil. Representative systems provide continuous monitoring via two complementary means: parallel pairs of ported (leaky) coaxial cables and a fiber optic cable, each pair of coaxial cables associated with a fiber optic cable. A fiber optic system, with associated light source, processor and display, together with an RF system, provides data to a remote location via telemetry or cellular phone, or both. The fiber optic cable(s) allow monitoring of displacement and vibrations within the structure. The ported coaxial cables, with associated RF source, using the same processor, display and telemetry used with the fiber optic sub-system, provide data for monitoring moisture change correlated to changes in the dielectric constant of surrounding material.

Abstract: A method for predicting bearing failure of a differential bearing including an inner race, an outer race, and a plurality of rolling elements positioned between the inner and outer race. The method includes coupling a strain gage to the differential bearing, generating a bearing performance model, receiving a signal from the strain gage, and comparing the strain gage signal to the bearing performance model to predict a differential bearing failure.

Abstract: A detection system and method are provided having vehicle-mounted and manportable mobile surveillance capabilities with minimal equipment redundancy. The system comprises a vehicle-mounted sensor unit, a hand-held unit, a manportable unit and a vehicle-mounted air collector unit. The vehicle-mounted sensor unit comprises a spectroscopy subsystem that is configured to direct light onto a surface outside the vehicle and to capture scattered optical energy from the surface outside the vehicle while the vehicle is moving. The hand-held unit may be removably mounted to the air collector unit to interrogate airborne particles in collected air. The hand-held unit is removable from the air collector unit and is connected to the manportable unit by a cable so as to form an integrated portable detection system for mobile surveillance away from the vehicle by a user.

Abstract: In accordance with an aspect of the present invention, there is provided a photoelastic coating for structural monitoring comprising an optically translucent or transparent photoelastic layer. The photoelastic coating is applied to the structure as a solvent-based liquid or gel that can be cured without heating. The photoelastic properties of the photoelastic layer can be used to detect stress and strain or plastic deformation in the structure using photoelastic techniques. In accordance with another aspect of the invention, there is provided a method of structural monitoring using a photoelastic structural monitoring coating. The method comprises the steps of providing a structure for which structural monitoring is desired, applying a photoelastic layer to said structure as a solvent-based liquid or gel, and curing said photoelastic layer in place on said structure.

Abstract: A method of trace delay error compensation for measurements that are taken remotely from the signal source or receiver of a circuit uses data available from a computer aided design (CAD) tool to characterize electrical connections to an instrument measurement point, such as a connectorless probe, which is remote from the signal source or receiver. Extracted parameters from the CAD data are applied to signals acquired by the probe to adjust the signal timing and/or shape to more accurately represent the signal information timing at the signal source or receiver or other remote location of interest to a user. The corrected signals at the desired location may be displayed by a measurement instrument.

Abstract: A reinforcement element, comprises at least one sensor fiber adapted for strain measurements based on stimulated Brillouin scattering within said sensor fiber.

Abstract: An object of this invention is to provide stress measurement method that is stress of the measuring object nondestructively in a short period of time.

Abstract: In a stress measuring apparatus, reflected light of light emitted to a substrate through an objective lens is received by a light shielding pattern imaging part, to acquire an image of a light shielding pattern positioned at an aperture stop part of an optical system. A control part obtains gradient vectors of the substrate in a plurality of gradient vector measurement areas and surface form of the substrate on the basis of outputs of the light shielding pattern imaging part, to obtain a stress in a film formed on the substrate. Since light directed through the objective lens becomes approximately parallel rays of light on the substrate, measurement can be performed without focusing on each gradient vector measurement area and the surface form of the substrate can be obtained easily and rapidly. Consequently, it is possible to obtain a stress in the film formed on the substrate easily and rapidly.

Abstract: A crack detection system and a method for detecting cracks in a loaded engineering structure are provided. The system and method include a light source coupled and optical fibres that are led through the structure. The optical fibres have diameters below 75 ?m. The light source is coupled to the optical fibres.

Abstract: A method and system for simultaneously measuring strain and temperature characteristics of an object involves the attachment to the object of a pair of optical fibers having different refractive indices, the fibers being connected together at least one end thereof, and directing laser light into at least one end of the fibers. The Brillouin frequency of each of the fibers is measure and the strain and temperature characteristics are calculated based on the coefficients of strain and temperature and the measured Brillouin frequencies of the fibers.

Abstract: Disclosed is a system for measuring stator wedge tightness in a stator core of an electric machine. The system includes at least one sensor located along at least one component disposed in a stator slot of the stator core. The at least one sensor is located and configured to measure strain in the component. The system further includes a data acquisition system operably coupled to the at least one sensor. A method for measuring stator wedge tightness in a stator core of an electric machine includes arranging at least one sensor along at least one component of the stator core, the at least one sensor being located and configured to measure strain in the component, and interrogating the at least one sensor utilizing a data acquisition system.

Abstract: A method of detecting local mechanical stress in integrated devices is provided, the method comprising: enabling the detection of a photovoltage difference between a scan probe device and a surface portion of an integrated device, the scan probe device being configured to deflect in response to the photovoltage difference; measuring the deflection of the scan probe device in response to the photovoltage difference between the scan probe device and the surface portion of the integrated device; and calculating a local stress level within the integrated device by determining a local work function of the surface portion of the integrated device based upon the deflection of the scan probe device.

Abstract: It is possible to observe a state of stress applied to a region around a cavity replicating a body cavity such as a blood vessel and the like in a three-dimensional model. In catheter insert simulation, when stress is applied to the region around the cavity in the three-dimensional model, it is possible to observe the catheter state together with a photoelastic effect corresponding to the stress state in the surrounding region caused by the catheter.

Abstract: The present invention provides an evaluation method for evaluating whether a light-emitting element material to be evaluated is suitable for a host material or a guest material. By carrying out a first step of measuring absorption intensity of a light-emitting element material and a second step of irradiating the light-emitting element material with light for a predetermined period of time, repeatedly; thereby a change in absorption intensity with time is evaluated so that whether the light-emitting material is suitable for a host material or a guest material can be distinguished. The light emitted to the light-emitting element material preferably has a wavelength component which is absorbed by a skeleton which contributes to excitation of the light-emitting element material.

Abstract: A system for determining at least one condition of a seal including an optical fiber for transmitting light from a light source. The optical fiber is embedded in the seal and operatively coupled to an interferometric system. The interferometric system is operatively coupled to a processor. The interferometric system provides the processor with information relating to wear of the optical fiber, and the processor determines wear of the seal, rate of wear and remaining useful life of the seal based on the information relating to wear of the optical fiber.

Abstract: The present invention relates to a sensor or the like having a structure that enables accurate temperature measurement in a wide temperature range including a low-temperature region and is suitable for independently and accurately determining temperature variations and strains appearing in an object to be measured. The sensor comprises a laser light source, a sensor section that has a plurality of waveguides transmitting a laser light from the laser light source therethrough, a detecting section, and an analyzing section. The detecting section detects a plurality of Brillouin spectra obtained from the sensor section. The analyzing section determines at least one measurement value of a temperature in the sensor section and a strain generated in the sensor section, based on fluctuations of parameters defining the respective detected Brillouin spectra. In particular, the sensor section has a structure such that the variation of the Brillouin spectrum in response to a disturbance differs between the waveguides.

Abstract: A method and system for measuring radial strain on powder or other granular material while the powder is subject to compressive axial and radial loading. The powder is contained within a pliable sleeve. As pressure is applied to the powder, the sleeve changes diameter. An optical emitter emits a beam of light, which is intersected by the entire diameter of the sleeve. An optical sensor receives the intersected beam, and generates a response signal that indicates the diameter of the sleeve. This change in diameter can be related to a constitutive property such as strain.

Abstract: The temperature measuring device of the present invention comprises: a light source for outputting light; an optical fiber to which light outputted by the light source is inputted and from which Brillouin scattered light is outputted; a detection unit for detecting a spectrum of the Brillouin scattered light; a judgment unit for judging whether or not a frequency shift of the spectrum of the Brillouin scattered light detected by the detection unit belongs to a specific region in which the rate of change of the frequency shift with respect to the temperature of the optical fiber is smaller than a predetermined value; and an analysis unit for, when the judgment unit judges that the frequency shift does not belong to the specific region, analyzing the temperature in use of the frequency shift, and for, when the judgment unit judges that the frequency shift belongs to the specific region, not performing analysis, or analyzing the temperature in use of at least the linewidth of the spectrum of the Brillouin scatte

Abstract: A bonded part peeling shape identification device includes: a processor for obtaining measurement value information indicating a spectrum from an output light of an optical fiber sensor arranged in a bonded part, the optical fiber sensor outputting a light in which the spectrum is changed according to a strain; for carrying out a first shape identification calculation using a strain calculated based on the measurement value information, and a second shape identification calculation by a spectral shape of the output light based on the measurement value information; and for identifying a peeling shape of the bonded part based on an identification result of the first shape identification calculation and an identification result of the second shape identification calculation.

Abstract: An instrument for use in a borehole, the instrument including a pressure tuned light source disposed in a housing adapted for insertion into the borehole.

Abstract: To perform distributed sensing with an optical fiber using Brillouin scattering, a light pulse is transmitted into the optical fiber, where the transmitted light pulse has a first frequency. Backscattered light and optical local oscillator light are combined, where the backscattered light is received from the optical fiber in response to the transmitted light pulse, and where the optical local oscillator light has a second frequency. A frequency offset is caused to be present between the first frequency of the transmitted light pulse and the second frequency of the optical local oscillator light, where the frequency offset is at least 1 GHz less than a Brillouin frequency shift of the backscattered light. Spectra representing Stokes and anti-Stokes components of the backscattered light are acquired, where the Stokes and anti-Stokes components are separated by a frequency span that is based on the frequency offset.

Abstract: The present invention provides an evaluation method for evaluating whether a light-emitting element material to be evaluated is suitable for a host material or a guest material. By carrying out a first step of measuring absorption intensity of a light-emitting element material and a second step of irradiating the light-emitting element material with light for a predetermined period of time, repeatedly; thereby a change in absorption intensity with time is evaluated so that whether the light-emitting material is suitable for a host material or a guest material can be distinguished. The light emitted to the light-emitting element material preferably has a wavelength component which is absorbed by a skeleton which contributes to excitation of the light-emitting element material.

Abstract: An image pickup device disposed in a predetermined position relative to a surface of a strained silicon wafer photographs the surface of the strained silicon wafer in a plurality of rotation angle positions on photographing conditions under which bright lines appearing on the surface of the strained silicon wafer can be photographed, in an environment where a light source device illuminates the surface of the strained silicon wafer which is rotating. A composite image in a predetermined angle position is generated from surface images of the strained silicon wafer in a plurality of rotation angle positions obtained by the image pickup device.

Abstract: A dimension sensor is used in conjunction with a tube and includes a body member and at least one detector element. The body member has an inner surface defining an opening sized to receive the tube. The at least one detector element is connected to the body member and has a detector portion extending into the opening. When the tube is received in the opening, the detector portion is initially disposed apart from the tube. A method using the dimension sensor stops expansion of the tube expanding from a pre-expanded state to a desired expanded state. A pumping device is actuated to pressurize a fluid by an amount sufficient to cause the tube to expand from the pre-expanded state to the desired expanded state. When the tube expands to the desired expanded state, the pumping device deactivates thereby stopping expansion of the tube at the desired expanded state.

Abstract: In a method and system for evaluating sub-critical fatigue crack growth in a semiconductor device, a plurality of energy pulses generated by an energy source are repeatedly impinged onto the semiconductor device for a predefined time interval. The repeated impinging of the plurality of energy pulses induces a mechanical stress within the semiconductor device. The induced mechanical stress, maintained below a threshold and repeated for a predefined number of cycles, causes a formation of a sub-critical fatigue crack within the semiconductor device. A detector detects the presence of the sub-critical fatigue crack leading to a fatigue failure. A rapid determination of a pass or fail status for a fatigue test of the semiconductor device is made by comparing a total number of cycles to fatigue failure to a predefined benchmark.

Abstract: The present invention relates to a monitoring device for a rotating body, which can accurately measure signals from a fiber Bragg grating sensor provided on the rotating body by compensating a transmission loss variation and a distortion of the sensor signals. A rotation-side optical fiber has at least one deformation sensor at a portion thereof and a reference sensor at one end thereof. The sensors are made by forming a Bragg grating in the rotation-side optical fiber. A fixed-side optical fiber is mounted to the fixed body so as to be opposed to the one end of the rotation-side optical fiber. A signal processing unit detects a deformation of the rotating body by subtracting a signal corresponding to the light reflected from the reference sensor from a signal corresponding to the light reflected from the deformation sensor.

Abstract: An optical linear strain gage includes a target, a sensor, and a computer, wherein the target contains a gage length defined by end points. The target can be a one-dimensional barcode, the gage length defined between, and perpendicular to, two chosen parallel lines of the barcode. The target, including a gage length, is associated with an object such that deformation of the gage length and deformation of the object are the same; target can emit or reflect a detectable physical quantity. The sensor is compatible with and pre-processes the physical quantity from the target and provides data to the computer. The computer analyzes the data output and calculates the strain directly on the body based on the pre-processed and analyzed data. Measuring strain on an object using the strain gage includes identifying the changes in the gage length as a function of time and load applied and calculating strain.

Abstract: The device enables strains of at least one surface (1) of a sample (2) to be measured versus temperature. Strains in a direction perpendicular to a predetermined plane, for example the plane of the surface (1), are measured by composite images. Strains in said plane are measured by image correlation. The measurements by image correlation and by composite images use a common visible light detection camera (3). The sample (2) is arranged in an enclosure (6) transparent at least locally to visible light (L). At least one infrared emitter (9) enables an infrared light to be created in a spectral band for a large part not detected by the camera (3).

Abstract: An optical fringe generation member control apparatus includes a detection unit configured to detect an optical fringe, and a control unit configured to control operation of a member on which the optical fringe is generated, based on a detection result by the detection unit.

Abstract: A method and apparatus are provided for detecting strain, stress, fatigue and incipient failure in materials. A detector (e.g., a photomultiplier tube) is used to detect photonic emissions from a material under test. Data based on the detected photonic emissions is displayed in real time so as to enable real time analysis of the data in determining strain, stress, fatigue and/or incipient failure.

Abstract: The present invention relates to an apparatus for determining the shear sensitivity of particles in solutions and methods of determining the respective shear velocities or the respective shear stress.

Abstract: A method and system for simultaneously measuring strain and temperature characteristics of an object involves the attachment to the object of a pair of optical fibers having different refractive indices, the fibers being connected together at least one end thereof, and directing laser light into at least one end of the fibers. The Brillouin frequency of each of the fibers is measure and the strain and temperature characteristics are calculated based on the coefficients of strain and temperature and the measured Brillouin frequencies of the fibers.

Abstract: Photoelastic elements are formed deliberately with stress concentrations so that, when evaluated with a polariscope, more pronounced isochromatic bands or fringes result when loads are applied to these elements or to assemblies of these elements. A toy for producing color patterns and having polarizing filters coupled to frame elements is disclosed.

Abstract: An optical measurement apparatus and method a method for performing modulation spectroscopy measurement of a sample comprising: delivering an incident probe beam to a sample at a known spot; modulating reflectance of the probe beam with a pump beam which periodically forms a pump beam spot on the sample coincident with the probe beam spot; and monitoring a reflected probe beam with a detector: wherein the incident probe and pump beams are collinear; and wherein the incident beams are directed to be collinear by reflecting a beam from a facet of an optical waveguide transmitting the other beam.

Abstract: The invention relates to a system for distributed or dispersed measurement of axial and bending deformations of a structure including at least one threadlike device (10) equipped for the distributed or dispersed measurement of these axial and bending deformations, and means for processing measurement signals generated by said device, in which each device includes a cylindrical reinforcement (11) supporting, at its periphery, at least three optical fibres (12) locally parallel to the axis of the reinforcement, and in which the processing means implement means for spectral or time division multiplexing of signals coming from optical fibres.

Abstract: Process control monitors are disclosed that are produced using at least some of the same process steps used to manufacture a MEMS device. Analysis of the process control monitors can provide information regarding properties of the MEMS device and components or sub-components in the device. This information can be used to identify errors in processing or to optimize the MEMS device. In some embodiments, analysis of the process control monitors may utilize optical measurements.