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 67 for “"fiber optic sensors"”.
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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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Fiber-optic sensors for weigh-in-motion application
… and 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
… beyond 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 …
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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 …
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Detection and Position Location of Partial Discharges in Transformers Using Fiber Optic Sensors
… extrinsic Fabry-Parot 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 …
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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 …
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STRAIN AND TEMPERATURE MEASUREMENT FROM DISTRIBUTED FIBER OPTIC SENSORS IN PERFORMANCE-BASED FIRE ENGINEERING
… characterizes 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 …
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Theoretical and Experimental Study of Low-Finesse Extrinsic Fabry-Perot Interferometric Fiber Optic Sensors
… extrinsic 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 …
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Comparison of Strain Gage and Fiber Optic Sensors On A Sting Balance In A Supersonic Wind Tunnel
… With 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 …
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CO2-rock interaction during CO2-enriched brine injection into storage reservoirs using NMR integrated with fiber optic sensors
… are not captured by LVDT and ESG. Therefore, Fiber Bragg Grating (FBG) sensing has become a promising alternative due to its various advantages, such as resistance to electromagnetic interference, high-pressure and -temperature, small size, multiplexing capability, amongst others. In this …
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Use of sensors in monitoring civil structures
This thesis surveys the use of sensors and sensor networks in monitoring civil structures, with particular emphasis on the monitoring of bridges and highways using fiber optic sensors. Following a brief review of the most widespread form of civil infrastructure inspection -- visual inspection -- …
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Self-Calibrated Interferometric/Intensity Based Fiber Optic Temperature Sensors
… the objective of providing robust and reliable fiber optic temperature sensors capable of operating in harsh environments, a novel type of fiber optic sensor system titled self-calibrated interferometric/intensity-based (SCIIB) fiber optic temperature sensor system is presented in this thesis …
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Novel applications of pulse pre-pump Brillouin Optical Time Domain Analysis for behavior evaluation of structures under thermal and mechanical loading
… for the strain transfer effect of distributed fiber optic sensors in a uniform or non-uniform stress field; (2) develop a measurement approach to monitor strains in concrete and detect damage (e.g. crack and delamination) in bonded and unbonded concrete overlays; (3) characterize the strain and …
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Advancing Sensing and Structural Health Monitoring of Non-Conventional Space Structures
… advanced photogrammetry and embedded distributed fiber-optic sensors. A color-filtering digital image correlation technique was developed to isolate orthogonal strain directions in woven inflatable structures, providing improved characterization of biaxially loaded softgoods. In addition, methods …
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Integrated Liquid/Steam Multiphase Flow Sensors for Geothermal Applications
… present phases. This study proposes the use of fiber optic sensors to detect the multiphase flow. The Department of Energy (DOE) is interested in creating steam wells, and the purpose of the research is to determine the capabilities of fiber optic sensors developed by NanoSonic Inc. to operate …
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