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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 25 for “"white-light interferometry"”.
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Bayesian Estimation for White Light Interferometry
… the reconstruction of height maps from scanning white light interferometry is presented. This method unifies the conventional steps of pre- and postprocessing within Bayesian inference. An adept formulation of the prior allows for the exact computation of the height estimate, obviating the need …
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Signal processing techniques for optical fiber sensors using white light interferometry
… limitation can be overcome by using a broadband light source to extract unambiguous information from the sensor in the wavelength domain. Several variations in the signal processing techniques for white light interferometry are discussed and compared in terms of resolution, bandwidth and cost. A …
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Sapphire Fiber Optic Sensor for High Temperature Measurement
… signal demodulation. The research goal is highlighted. In Chapter 2, a temperature sensing system is introduced. The environmental thermal radiation was used as the broadband light source. A sapphire wafer F-P temperature sensor head was fabricated, with an alumina cap designed to generate a …
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Optical Path Length Multiplexing of Optical Fiber Sensors
… (OPLM) is a modification to traditional white-light interferometry techniques to multiplex extrinsic Fabry-Perot interferometers and optical path length two-mode sensors. Additionally, OPLM techniques can be used to design an optical fiber sensor to detect pressure/force/acceleration and …
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Fabrication of high-quality microflexures using micromilling techniques
… part was verified using optical microscopy and white-light interferometry to inspect for any microcracks or otherwise unfavorable by-products of the milling process. Ultimately, it was shown that micromilling is a feasible process for manufacturing low-volume to-spec mesoscale nanopositioners …
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Development Of Silicon-Based Anodes And In-Situ Characterization Techniques For Lithium Ion Batteries
… under cycling. For the in-situ measurement, a white light interferometry (WLI) and laser vibrometer were used to gather quantitative data. Amorphous silicon (<i>a</i>-Si) was explored for the stress measurement.</p>
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Modeling of contact between liner finish and piston ring in internal combustion engines based on 3D measured surface
… of liner surface needs to be obtained through white light interferometry device or confocal equipment to conduct contact model. Based on real geometry of liner finish and the assumption that ring surface is ideally smooth, contact can be predicted by three different models which were developed …
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Modeling and Signal Processing of Low-Finesse Fabry-Perot Interferometric Fiber Optic Sensors
… of the sensors, and signal processing based on White-Light-Interferometry (WLI). In the first chapter, the technical background of the low-finesse FPI sensor is briefly reviewed and the problems to be solved are highlighted. A model for low finesse Extrinsic FPI (EFPI) is developed in Chapter 2. …
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Development of a Fourier Domain Low Coherence Interferometry Optical System for Applications in Early Cancer Detection
… technique called Fourier domain low coherence interferometry (fLCI). </p><p>The presented work first describes a detailed analysis of temporal and spatial coherence. The study shows that temporal coherence information in time frequency distributions contains valuable structural information …
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Design and dynamic simulation of mobile manipulators incorporating tribological analysis of 16MnCr5 and EN19 steels.
… of surface characterisation carried out using white light interferometry, digital microscopy and scanning electron microscopy substantiate the COF measurements. Microhardness of the surface was also analysed and showed that coatings improved the surface hardness by 19.7% to 55.9%. Therefore, …
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Development of Tunable Optical Filters for Interrogation of White-Light Interferometric Sensors
… recovery of a measurand from the phase-modulated lightwaves, and has been a challenge for high performance, high speed, and low-cost, to current white-light interferometry (WLI) techniques, such as the widely used scanning WLI (S-WLI) and spectral-domain WLI (SD-WLI). The performance of a …
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Laser surface modification of biomedical alloys
… using the scanning electron microscope. White light interferometry and stylus profilometry were used to determine the surface roughness. X-ray diffractometry was used to investigate the crystallinity and phase transformation induced by the laser treatment. Micro-hardness was measured …
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High Temperature High Bandwidth Fiber Optic Pressure Sensors
… high operation temperature, immunity to EMI, lightweight and long life. Static and dynamic pressure measurements at various locations of a gas turbine engine are highly desirable to improve its operation and reliability. However, the operating environment, in which temperatures may exceed 600 …
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Optical Sensors for High-Temperature Pressure Measurement and Real-Time Particle Detection
… has been demonstrated at room temperature using white-light interferometry. For the other sensor, the goal is to detect the presence of micro- and nanoparticles in real time. The sensor is based on a silica fiber taper, and we aim to detect particle presence by measuring optical scattering and …
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Power scaling and nonlinear conversion in fiber-based sources at novel wavelengths
… available photonic crystal fibers through white light interferometry and femtosecond nonlinear pulse propagation. The custom-drawn photonic crystal fiber demonstrated a 5x improvement in dispersion uniformity and greater spectral similarity between forward and backward pulse propagation. …
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Defect tolerance assessment of silicon nitride in rolling contact.
… contact fatigue. Scanning electron microscopy, light microscopy and white light interferometry are used for surface analysis and topography. Post-experiment analysis in the star feature experiments has shown that star like radial cracks are prone to develop into missing material by internal …
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High Speed Wavelength Tuning of SGDBR Lasers for Optical Coherence Tomography Applications
… into samples under test with a focused infrared light source. Swept wavelength OCT requires a laser light source that is capable of sweeping its wavelength quickly over the entire wavelength range of the tunable laser. Fast sweeping of the laser's wavelength enables real-time imaging of a wide …
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Fluvial bedrock abrasion by bedload : process and form
… marble plates was determined using optical white light interferometry in a controlled laboratory study. The influence of sphere diameter, impact angle and impact velocity were investigated and empirical relationships between these variables determined. In all 782 impact craters measured in …
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High Speed Fiber Optic Spectrometer
… medium accuracy and measurement ambiguity. The white light interferometry could provide a solution for high accuracy and large dynamic range measurement without ambiguity because of its absolute measurement nature. However the signal demodulation speed is limited due to the low spectrum …
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Fabry-Perot Sapphire Temperature Sensor for Use in Coal Gasification
Sapphire fiber based temperature sensors are exceptional in their ability to operate at temperatures above 1000C and as high as 1800C. Sapphire fiber technology is emerging and the fiber is available commercially. Sapphire fiber has a high loss, is highly multi-mode and does not have a solid …
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