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Full-Text Articles in Engineering
Design Of A Low-Cost Capillary Electrophoresis Laser-Induced Fluorescence System: Lessons Learned When Trying To Build The Lowest Possible Cost System, Steven James Perry
Design Of A Low-Cost Capillary Electrophoresis Laser-Induced Fluorescence System: Lessons Learned When Trying To Build The Lowest Possible Cost System, Steven James Perry
Theses and Dissertations
Capillary electrophoresis laser-induced fluorescence (CE-LIF) is widely used to detect both the presence and concentration of fluorescently labeled biomolecules. In CE-LIF, a plug of sample fluid is electrophoretically driven down a microchannel using a high voltage applied between the opposite ends of the microchannel. Molecules of different sizes and charge states travel at different velocities down the channel. Laser light with a wavelength in the excitation band of the fluorophores is focused near the end of the channel. As each species of molecule passes through the laser spot, the fluorophores emit a fluorescence signal which is measured with an optical …
Design Of A Low-Cost Capillary Electrophoresis Laser-Induced Fluorescence System: Lessons Learned When Trying To Build The Lowest Possible Cost System, Steven James Perry
Design Of A Low-Cost Capillary Electrophoresis Laser-Induced Fluorescence System: Lessons Learned When Trying To Build The Lowest Possible Cost System, Steven James Perry
Theses and Dissertations
Capillary electrophoresis laser-induced fluorescence (CE-LIF) is widely used to detect both the presence and concentration of fluorescently labeled biomolecules. In CE-LIF, a plug of sample fluid is electrophoretically driven down a microchannel using a high voltage applied between the opposite ends of the microchannel. Molecules of different sizes and charge states travel at different velocities down the channel. Laser light with a wavelength in the excitation band of the fluorophores is focused near the end of the channel. As each species of molecule passes through the laser spot, the fluorophores emit a fluorescence signal which is measured with an optical …
Application Improvements Of Slab-Coupled Optical Fiber Sensors, Spencer L. Chadderdon
Application Improvements Of Slab-Coupled Optical Fiber Sensors, Spencer L. Chadderdon
Theses and Dissertations
This dissertation explores techniques for improving slab-coupled optical fiber sensor (SCOS) technology for use in specific applications and sensing configurations. SCOS are advantageous for their small size and all-dielectric composition which permit non-intrusive measurement of electric fields within compact environments; however, their small size also limits their sensitivity. This work performs a thorough analysis of the factors contributing to the performance of SCOS and demonstrates methods which improve SCOS, while maintaining its small dimensions and high level of directional sensitivity. These improvements include increasing the sensitivity by 9x, improving the frequency response to include sub 300 kHz frequencies, and developing …
Directional Electric Field Sensing Using Slab Coupled Optical Fiber Sensors, Daniel Theodore Perry
Directional Electric Field Sensing Using Slab Coupled Optical Fiber Sensors, Daniel Theodore Perry
Theses and Dissertations
This thesis provides the details of a multi-axis electric field sensor. The sensing element consists of three slab coupled optical fiber sensors that are combined to allow directional electric field sensing. The packaged three-axis sensor has a small cross-sectional area of 0.5 cm x 0.5 cm achieved by using an x-cut crystal. The method is described that uses a sensitivity-matrix approach to map the measurements to field components. The calibration and testing are described resulting in an average error of 1.5º.This work also includes a description of the packaging method used as well as a thorough analysis of the directional …
Electric Field Sensing In A Railgun Using Slab Coupled Optical Fiber Sensors, Jonathan Robert Noren
Electric Field Sensing In A Railgun Using Slab Coupled Optical Fiber Sensors, Jonathan Robert Noren
Theses and Dissertations
This thesis discusses the application of Slab Coupled Optical Fiber Sensors (SCOS) in a railgun. The specific goal of these sensors is to create an electric field profile at a specific point in the gun as the armature passes. The thesis explores the theory that powers the railgun as well as the principles of the SCOS sensors. It also elaborates on the various noise sources found throughout the detection system and concludes with a summary of the various field tests that were performed throughout this project. There are many benefits to using a railgun over traditional weapons in the field. …
Magnetic Field Sensing With Slab Coupled Optical Fiber Sensors, Bryson J. Shreeve
Magnetic Field Sensing With Slab Coupled Optical Fiber Sensors, Bryson J. Shreeve
Theses and Dissertations
This thesis reports an in-fiber magnetic field sensor that is able to detect magnetic fields as low as 2 A/m at a spatial resolution of 1 mm. The small sensor consists of a magneto-optic slab waveguide, bismuth-doped rare earth iron garnet (Bi-RIG) that is coupled to an optical fiber. By coupling light from the fiber to the slab waveguide, it becomes an in-fiber magnetic field sensor. This is due to the Magneto-Optic Kerr effect; a change in refractive index is proportional to the applied magnetic field. When an AC field is applied, an AC component in the output power can …
Slab-Coupled Optical Fiber Sensors For Electric Field Sensing Applications, Richard S. Gibson
Slab-Coupled Optical Fiber Sensors For Electric Field Sensing Applications, Richard S. Gibson
Theses and Dissertations
This dissertation presents the creation of slab coupled optical sensors (SCOS) for electric field sensing applications. SCOS devices utilize the benefits of an optical fiber system for high bandwidth and low electromagnetic interference. These sensors are fabricated by means of mode coupling between a small section of D-shaped optical fiber (D-fiber) with a multi-mode electro-optic slab waveguide. Electric field detection is accomplished by monitoring the behavior of the resonances, seen as transmission dips in the D-fiber transmission, as they shift with electric fields. The novelties of SCOS devices include their small compact nature, potential for sensor multiplexing and a dielectric …
Laser Levitation Of Solid Particles For Combustion And Gasification Applications, Skigh E. Lewis
Laser Levitation Of Solid Particles For Combustion And Gasification Applications, Skigh E. Lewis
Theses and Dissertations
This dissertation details theoretical and experimental work in the development of a novel combustion diagnostic: laser levitation of solid particles. Theoretical analyses of the forces involved in the suspension of solid particles in a laser beam provide a comprehensive description of the levitation mechanism. Experimental work provides extensive observations and data that describe each of the forces involved, including results from detailed models. Theoretical models establish that a free-convective drag force, light scattering, photon momentum, and other minor forces contribute to the trapping mechanism. The theory quantitatively predicts particle temperature and magnitudes of each of the forces involved. Experimental measurements …
Solid-State Impact-Ionization Multiplier, Hong-Wei Lee
Solid-State Impact-Ionization Multiplier, Hong-Wei Lee
Theses and Dissertations
This dissertation presents an innovative solid-state current amplifier based on impact-ionization. Unlike avalanche photodetectors which use the same amplification principle, this device can be integrated with any external current source. A discrete amplifier was built on a silicon surface using standard CMOS fabrication processes including lithography, oxidation, ion implantation, diffusion, chemical wet etching, metal deposition, annealing, and rapid thermal processing. Testing was performed by connecting the device to a silicon photodiode, indium-gallium-arsenide photodiodes, and a function generator to demonstrate its compatibility with arbitrary current sources. Current gains above 100 along with pre-amplified leakage currents of less than 10 nA were …
Development Of A Virtually Calibrated Projection Moire Interferometry Technique Capable Of Inaccessible Surface Measurements, Mark Lee Kimber
Development Of A Virtually Calibrated Projection Moire Interferometry Technique Capable Of Inaccessible Surface Measurements, Mark Lee Kimber
Theses and Dissertations
Optical-based techniques have found merit in measuring displacement and strain for decades. These techniques are commonly used in numerous applications ranging from large displacements in wind tunnel experiments to displacement measurements on the submicron scale. Projection Moiré Interferometry (PMI) is an out-of-plane displacement measurement technique, and consists of capturing reference and deformed images of a grid pattern projected on the test object. By differencing the reference and deformed images of the projected grid pattern, a fringe pattern is generated from which the displacement field can be extracted. This computation requires calibration procedures that analyze a number of fringe patterns from …
Modeling Electromagnetic Wave Propagation In Electrically Large Structures, Jon Wallace
Modeling Electromagnetic Wave Propagation In Electrically Large Structures, Jon Wallace
Theses and Dissertations
Existing unified numerical electromagnetic methods are often unable to analyze electrically large structures due to the amount of memory and processing power required, necessitating approximate analyses with limited applicability. In this research a hybrid modeling methodology is adopted to solve these complex problems more efficiently than unified numerical methods and more accurately than analytical methods. Electromagnetic modeling problems are divided into two or more levels of scale. Each level analyzes a specific level of detail and only promotes the required information to the next level. The method is demonstrated by successful application to three important problems: (1) remote sensing of …