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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 69 for “"FBG"”.
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High-resolution Photon Counting OTDR based Interrogation of Multiplexing Broadband FBG Sensors
Fiber-optic Bragg grating (FBG) sensors are a very attractive technology for the measurement of strain and temperature. They have many advantages over conventional sensors in sensing applications such as sensitivity, immunity to electromagnetic interferences,large bandwidths,capability of remote …
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Optical fiber temperature sensor based on fiber bragg grating
… the limits of reflected and transmitted for FBG sensors. The FBG temperature sensor, is essential to establish the smallest distance of single mode fibre in order to reduce optical losses of the FBG system. One of the most generally used deployed optical sensors is the fiber Bragg grating, …
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Passive and active Bragg gratings for optical networks
This thesis investigates fibre Bragg grating (FBG) devices. Specifically, it consists of the developments and applications of two groups of devices: the optical phase en/decoders and the tunable fibre Bragg gratings based on an S-bending technique. The advantage of an S-bending tuning FBG is that …
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Strain sensor using fiber bragg grating interrogation
… of strain sensor using Fiber Bragg Grating (FBG) interrogation. Studies on fiber optic sensors reported have mainly focused on FBG wavelength-based monitoring method by using optical spectrum analyzers (OSA). Although FBG has better strain sensitivity measurement, however there have some …
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Fiber Optic Sensing of Strain and Temperature for Structures in a Hypersonic Flow
Research into multi-sensor fiber Bragg grating (FBG) networks has the potential to benefit aircrafthealth monitoring systems. The overall goal of this thesis research is to demonstrate that FBG sensors can be used to measure temperature and strain data of a structure in a hypersonic flow. To that …
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A Quasi-distributed Sensing Network Based on Wavelength-Scanning Time-division Multiplexed Fiber Bragg Gratings
… in harsh environments. Fiber Bragg grating (FBG) has attracted considerable interest for this application because of its compactness, electromagnetic immunity, and excellent multiplexing capability. Several FBG multiplexing techniques have been developed to increase the multiplexing number …
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Fiber Bragg Gratings Strain Sensors for Railway Applications
… electrical counterparts. A fiber Bragg grating (FBG) strain sensor has been employed for this study to detect and distinguish normal and lateral loads on rail tracks. A theoretical analysis of the relationship between strain and displacement under vertical and horizontal strains on an aluminum …
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CO2-rock interaction during CO2-enriched brine injection into storage reservoirs using NMR integrated with fiber optic sensors
… 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 study, FBG sensing …
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Distributed optical fibre smart sensors for acoustic sensing in the structural health monitoring of robust aerospace vehicles
… dynamic strain signals. Fibre Bragg Gratings (FBGs) were chosen as the optical fibre sensor for the detection of the acoustic signals. FBGs offer significant advantages over other types of optical fibre sensors. The most significant of these is the ease of multiplexing and their versatility, …
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STAT3-protein interactions in IL-6/gp130 signaling
… (CDK9) was examined by using gamma-Fibrinogen (ã-FBG), an acute phase protein, as a model. IL-6 induces a strong nuclear association of STAT3 with CDK9, which is mediated via both STAT’s NH2-terminal and COOH-terminal domains. The induction of ã-FBG by IL-6 is significantly decreased when CDK9 is …
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Hindgut fermentation in ruminating Holstein calves
… low starch, fishmeal plus dried brewers' grains (FBG); [Hl] high starch and SBM; [H2] high starch, FBG. The percentages of acid detergent fiber (ADF) and crude protein were: [L1] 19.2%, 15.1%; [L2] 18.0%, 15.6%; [H1] 9.5%, 14.9%; [H2] 9.6%, 15.4%. After calves were fed the diets for 17 days, they …
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Adaptive Control of Waveguide Modes in Two-Mode Fibers
… fiber coupler or fiber Bragg gratings (FBGs). Using the coupling ratio of a directional coupler as feedback, we demonstrate adaptive control of LP modes at the two output ports of the directional coupler. With feedback determined by the relative magnitude of optical power reflected by a …
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Monitoring of Overhead Polymer Core Composite Conductors Under Excessive Mechanical Loads Using Fiber Bragg Grating Sensors
… Furthermore, the use of Fiber Bragg Grating (FBG) sensors was investigated for the first time to monitor the ACCC® design during installation and in-service.</p> <p>Transverse low-velocity impacts to the ACCC® conductor having either free or constrained end conditions and large axial tensile …
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Optical pulse distortion and manipulation through polarization effects and chromatic dispersion
… ultra-long length chirped fiber Bragg gratings (FBG). Their enormous chromatic dispersion enables methods of improving current techniques in sensing and high speed optical sampling. In one experiment, we modulate the frequency of a standard distributed Bragg reflector (DBR) laser, and then apply …
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Intensity based interrogation of optical fibre sensors for industrial automation and intrusion detection systems
… reviewed in this thesis. Fibre Bragg grating (FBG) sensing is one form of optical fibre sensing that has been underutilised in applications such as in-ground, in-fence, and window and door monitoring, and addressing that opportunity has been a major goal of this thesis. Both security and …
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Chloride Selective Gold Coated Fiber Bragg Grating Sensor
… gold-plated Fiber Bragg Grating (FBG) sensor that can detect chloride with good resolution. This sensor is designed for applications in water treatment plants and swimming pools where safety and quality matter. And for better results, we use Atomic Layer Deposition (ALD), which …
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Resonant cavity Fibre Bragg grating sensor interrogation
… (TDM) fibre Bragg grating (FBG) optical sensors, known as the resonant cavity architecture. A background theory of FBG optical sensing includes several techniques for multiplexing sensors. The limitations of current wavelength-division-multiplexing (WDM) schemes are …
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Developing a Multi-axis Femtosecond Laser Micromachining Platform for Laser Induced Refractive Index Modification: Fiber Bragg Gratings, Waveguides, and Beyond
… Parametric Amplifier. Precise control over FBG pitch and length were achieved, with results showcasing strong refractive index modifications. FBGs exhibited reflectivity’s exceeding 25 dB, and bandwidth of less than 200~pm for 1~mm long second order devices. High temperature annealing to …
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Cross sensitivity analysis of optical fibre-based sensing for high pressure, high temperature measurement in oil and gas applications.
… sensitivity function of fibre Bragg grating (FBG) and its physical mechanism has been developed. This analysis was based on the fact that FBG sensor was in the state in which temperature and pressure were simultaneously functioning. The main objective of this research is to investigate the …
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In-fiber Optical Devices Based on D-fiber
… of a surface relief fiber Bragg gratings (SR-FBGs) in the cladding above the core of the fiber. Because it is etched into the surface topography of the fiber, a SR-FBG can operate at much higher temperatures than a standard FBG, up to at least 1100 degrees Celsius. The performance of a SR-FBG …
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