Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 90 for “"Optic sensors"”.
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Interrogation of fibre optic sensors
… was to investigate the interrogation of fibre optic sensors using "off the shelf optical components and equipment developed mainly for the telecommunications industry. This provides a cost effective way of bringing fibre optic sensor systems to within the price range of their electro-mechanical …
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Fiber Optic Sensors for Liquid Identifications
<p>"The fiber optic Fabry-Perot interferometer (FPI) is a widely utilized sensing configuration, offering numerous advantages over conventional electronic sensors, including high accuracy, distributed sensing capabilities, immunity to electromagnetic interference, and compact size. In this study, …
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Modified Hydrogel Matrices in Fibre Optic Sensors
… device. The latter, also applying to chemical sensors, is possibly due to a lack of understanding of polymer support or membrane properties and hence failure to optimise membranes chosen for specific sensor applications. Hydrogels can be described as polymers which swell in water. In addition …
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Fiber-optic sensors for weigh-in-motion application
… possibly further errors. In this thesis, a fiber-optic sensor is proposed which measures the pressure generated by the weight of a vehicle. The system consists of a pneumatic tube filled with an incompressible fluid, a rubber pad embedding the tube, a diaphragm to convert pressure into …
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Miniature Fiber-Optic Sensors for High-Temperature Harsh Environments
… 600°C for today's large engines. Current fiber-optic sensor can operate up to about 300°C and even the most widely employed semiconductor sensors are limited below 500°C. The objective of this research is to push the limit of fiber-optic sensing technology in harsh environment applications for …
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Corrosion detection using metal coatings on fiber optic sensors
Fiber optic sensors have been utilized as corrosion sensors by depositing metal coatings to the surface of the sensors. Three types of fiber optic sensors were investigated as candidates for corrosion detection: the extrinsic Fabry-Perot interferometer (EFPI), the absolute extrinsic Fabry-Perot …
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Damage detection in civil and aerospace structures with fiber optic sensors
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1995, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1995.
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Fiber-Optic Sensors for Fully-Distributed Physical, Chemical and Biological Measurement
… sensing are mainly based on the detection of optical signals resulted from different elastic or non-elastic light-matter interactions including Rayleigh, Raman and Brillouin scattering. However, they can measure temperature or strain only to date. Therefore, there is a need for technologies …
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Fiber Optic Sensors for On-Line, Real Time Power Transformer Health Monitoring
… However current commercially available sensors can only be installed outside of transformers and offer indirect or delayed information. This research is aimed to investigate and develop several sensor techniques for transformer health monitoring. The first work is an optical fiber …
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Fiber optic sensors and networks for U.S. Navy shipboard tests and trials
… organization, telemetry cables for electrical sensors are strung throughout the ship immediately prior to the test being conducted. As the shipboard tests and trials become more numerous and complex this philosophy becomes expensive from a labor and materials point of view. This thesis proposes …
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Modeling and Signal Processing of Low-Finesse Fabry-Perot Interferometric Fiber Optic Sensors
… several theoretical issues in low-finesse fiber optic Fabry-Perot Interferometric (FPI) sensors. The work is divided into two levels: modeling of the sensors, and signal processing based on White-Light-Interferometry (WLI). In the first chapter, the technical background of the low-finesse FPI …
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Detection and Position Location of Partial Discharges in Transformers Using Fiber Optic Sensors
… interferometric (EFPI) fiber acoustic sensors which can survive the harsh environment of oil-filled transformers. This thesis work is focused on optimal arrangement of multiple sensors to monitor and locate PD activities in a power transformer. This includes the following aspects. …
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Multiplexing of interferometric fiber optic sensors for smart structure applications using spread spectrum techniques
… and skins provides an application to which fiber optic sensors bring unique capabilities and benefits. The primary cost in a network of fiber sensors is in the sources, receivers and associated hardware and can be prohibitive for a large number of sensors. Multiplexing of sensors based on spread …
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STRAIN AND TEMPERATURE MEASUREMENT FROM DISTRIBUTED FIBER OPTIC SENSORS IN PERFORMANCE-BASED FIRE ENGINEERING
… in six parts low-cost distributed fiber optic sensors and applies them to strain, and temperature measurements based on Rayleigh and Brillouin light scattering. The first part aims to quantify the Rayleigh scattering based measurement accuracy of distributed fiber optic sensors under a …
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Theoretical and Experimental Study of Low-Finesse Extrinsic Fabry-Perot Interferometric Fiber Optic Sensors
… Fabry-Perot interferometric (EFPI) fiber optic sensors together with their signal processing methods for white-light systems are presented. The work aims to provide a better understanding of the operational principle of EFPI fiber optic sensors, and is useful and important in the design, …
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DEVELOPMENT OF MAGNETO-OPTIC SENSORS WITH GALLIUM IN BISMUTH DOPED RARE-EARTH IRON-GARNET THICK FILMS
… field of 50 pT at 1 kHz. Unlike previous Magneto-Optic (MO) studies that typically used thin films of approximately 1um thickness, we used approximately 400um thick films to allow experimentation with the final, robust, ideal form the MO sensor would take. We measured what most other MO studies …
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Characterisation of cross-linking and moisture ingress detection in an epoxy/amine resin using fibre-optic sensors
… resin and composites. The feasibility of using optical fibre-based sensor systems for monitoring cross-linking reaction has been demonstrated previously. However, little work has been reported on the deployment of a single sensor to study the cross-linking kinetics and the diffusion of moisture. …
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Comparison of Strain Gage and Fiber Optic Sensors On A Sting Balance In A Supersonic Wind Tunnel
… the recent advancements of technology, new fiber optic sensors have been designed to replace the conventional foil strain gage sensors commonly found on balances, thereby offering several distinct advantages. The use of fiber optic sensors on a balance brings with it some potential advantages over …
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CO2-rock interaction during CO2-enriched brine injection into storage reservoirs using NMR integrated with fiber optic sensors
… Super Glue. The results showed that the FBG sensors were capable of accurately monitoring strain changes during UCS and hydrostatic compressive tests. Conventional methods were employed for comparison. The measured strain changes by FBG showed significantly higher precision and lower noise …
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Studies of measurement techniques for indirect chemical sensing based on fluorescence spectroscopy and applications for fibre-optic sensors
… was 500±25pW).<br/>A novel combination of ruby optical temperature sensor insert and oxygen sensing layer was demonstrated as a simultaneous temperature and oxygen sensor.<br/>A new fluorescence calibration standard consisting of thermally stabilised titanium-doped sapphire sample was …
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