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 25 for “"Optical diagnostic"”.
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Fuel Droplet Optical Diagnostic Techniques for Lean Premixed Prevaporized Aeroengine Combustors
… conditions. This work employs a combination of optical diagnostics to enhance the understanding of fuel spray dynamics. Here, Mie scattering is utilized to visualize and measure the penetration depth of fuel sprays inside the combustor at reacting conditions. Both Jet-A and synthetic aviation …
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A review of optical diagnostic techniques used to identify uranium spectral signatures
… event. This research aims to implement an optical diagnostic system capable of performing time-resolved emission spectroscopy to accurately identify actinide core signatures in the UV-visible regime. Primary system components included two different material spark chambers, one dust cloud …
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Development Of A Two-Color Optical Diagnostic For The Determination Of Engine In-Cylinder Soot Temperature And Volume Fraction Evolution With A Flame-Calibrated Emissivity Model
… to quantify this parameter in-cylinder. Optical diagnostic techniques such as -- Rayleigh scattering, filtered Raman scattering (Doppler), Raman scattering, coherent anti-stokes Raman spectroscopy (CARS), vibrational thermally-assisted fluorescence, two-line atomic fluorescence, two-line …
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Experimental Investigation And Development Of An Extended Two Color Method (etcm) With Application To Internal Combustion Engines
… of interest to improve the application range of diagnostic tools such as the two color method (TCM) typically used in evaluating the properties of engine soot, such as temperature and volume fraction. This optical diagnostic method relies on the use of the light emitted by the soot particles …
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An experimental investigation of organized structure and mixing in compressible turbulent free shear layers
… on the nature of the mixing layer. Nonintrusive optical diagnostic techniques were employed to image the large structures. Both Mie scattering from condensed ethanol droplets and laser-induced fluorescence from seeded nitric oxide were used. The LIF experiments were utilized to avoid potential …
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Submicron patterning using laser interference lithography
… 1805 positive photoresist. In addition, an optical diagnostic was developed to interrogate the integrity of the grating structure, providing a qualitative assessment prior to investigation under the electron microscope.
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Localized Mechanical Compression as a Technique for the Modification of Biological Tissue Optical Properties
Tissue optical clearing aims to increase the penetration depth of near-collimated light in biological tissue to enhance optical diagnostic, therapeutic, and cosmetic procedures. Previous studies have shown the effects of chemical optical clearing on tissue optical properties. Drawbacks associated …
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Multi-Dimensional Quantitative Laser-based Diagnostics - Development and Practial Applications
Laser based optical diagnostic methods are routinely used in combustion research. Many of the more common approaches are based on illuminating a cross-section of the sample with a thin laser sheet. For example, by targeting an electronic transition in a molecule, its concentration within the plane …
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Modeling of no radiative emission in non-equilibrium hypersonic flow
… flows have to be measured using non-invasive optical diagnostic techniques. The creation of Nitric Oxide in hypersonic shocks can be measured both by radiative emission and absorption measurements. NO is an ideal optical diagnostic tool because it has a significant absorption cross section, …
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The Identification of Composite Resin Restorations within Natural Teeth
… using the three methods. The data showed that optical diagnostic accuracy range from 31.6% for visual examination, 25% for magnification to 92% for ultraviolet light. The specificity range from 85% for visual examination and 89.7% for magnification to 99% for ultraviolet light. The results …
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Unbiased Filtered Rayleigh Scattering Measurement Model for Aerodynamic Flows
The filtered Rayleigh scattering (FRS) optical diagnostic has become an attractive technique for advanced aerodynamic measurements. The appeal of FRS is that it can simultaneously quantify density, temperature, and vector velocity. Additionally, it is entirely non-intrusive to the flow since the …
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Visualising convective heat transfer in a propagating wildland fire
… burner, a custom-built wind tunnel, and advanced optical diagnostic techniques, including Retroreflective Shadowgraphy (RS) and Background Oriented Schlieren (BOS), to visualise and quantify heat transfer dynamics. Thermocouples, Pitot tubes, and heat flux sensors were used to capture physical …
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Spatially-resolved reflectance spectroscopy with variable fiber geometry
Optical techniques based on spectroscopic analysis have the potential for in vivo detection of early malignancies in tissue. Many optical modalities, including reflectance spectroscopy, use fiber optics as the means of light delivery and detection. However, the influence of fiber geometry on …
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Flame stabilization and mixing characteristics in a stagnation point reverse flow combustor
… pressure SPRF combustor with the help of various optical diagnostic techniques: OH PLIF, chemiluminescence imaging, PIV and Spontaneous Raman Scattering. Results indicate that the combustor is primarily stabilized in a region downstream of the injector that is characterized by low average …
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Novel Low Coherence Interferometric Tools for Early Detection of Cancer
… risk from more advanced disease. Developments in optical diagnostic techniques have shown promise in early detection of colorectal and cervical cancer, potentially able to improve upon existing preventative screening techniques in terms of accuracy and detection time.</p><p>This dissertation is …
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Optical diagnostics of lithium-sulfur and lithium-ion battery electrolytes using attenuated total reflection infrared spectroscopy
… to thermal runaway and catastrophic failure. An optical diagnostic technique to determine the order and concentration of polysulfides in Li-S battery electrolytes was developed from theoretical models and experimental measurements. The polysulfide diagnostic was used to study the evolution of …
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Development of mesoscale burner arrays for next generation compact gas turbines
… were experimentally investigated using several optical diagnostic and analysis techniques. Lean blow off limit, flame temperature, and NO emission measurements were performed on the mesoscale burner array; the obtained measurements were compared with those of a baseline single-swirl burner. …
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Experimental studies of novel accelerator structures at 11 GHz and 17 GHz
… frequency. This test stand provides comparable diagnostics to those used at SLAC, adding optical diagnostic access which can be used for open PBG structures. A conventional disc-loaded waveguide structure, MIT-DLWG, was tested at MIT at up to a 2 Hz repetition rate. This structure reached a …
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Development and Validation of Reconstruction Algorithms for 3D Tomography Diagnostics
… practical issues encountered in 3D tomography diagnostics, such as the limited view angles available in many practical applications, the large scale and nonlinearity of the problems when they are in 3D, and the measurement uncertainty. These algorithms are: an algebraic reconstruction technique …
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Laser Diagnostics Applied to Lean Premixed Swirling Flames - Simultaneous Flow Field and Scalar Measurements
… premixed swirling flames. Various laser-based optical diagnostic techniques were used to collect information under different operational conditions. Combined flow- and scalar field measurements were performed at high repetition rates for detailed studies of the turbulent flames. A large part of …
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