Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 109-110).

Rayleigh Scattering from neutral nitrogen and argon at room temperature has been studied using a 12 megawatt Q-switched pulse ruby laser. The scattering angle was chosen to be 90 degrees from the incident beam. The relative differential scattering cross-section and the pressure dependence of the scattered signal of the scattering media were determined. Measurements of the absolute differential cross-section of nitrogen and argon were also obtained. I found that the results agree very satisfactorily with the prediction of the theory within experimental error. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Thesis (M.A. Sc.)--University of Toronto, 2006. / Source: Masters Abstracts International, Volume: 45-03, page: 1547.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1983. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 186-191).

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Ultracentrifugation and imaging techniques of human blood serum are precise and information-rich methods for obtaining information about an individual’s lipoprotein particle content. The information derived from lipoprotein separations via an ultracentrifuge plays a key role in the area of preventative medicine in regards to atherosclerosis. Two of the most critical lipoprotein characteristics, diameter and density, are well preserved with the proper isopycnic gradient. Currently, lipoprotein particles are stained, ultracentrifuged, and profiled through image analysis. This particular technique is helpful in determining particle density and can be correlated loosely with particle concentration. The need to completely quantify lipoprotein concentrations is imperative in assessing risk factors accurately. Light scattering techniques, primarily Rayleigh scattering, are applied to density separated serum samples in resulting in improved qualitative data with progress in quantitative measurements through imaging alone. The Rayleigh theory dictates that a particle’s scattered intensity is based upon the incident intensity, the particle’s diameter, and the particle’s concentration when strict criteria are met within the sample and imaging apparatus. Applying this innovative imaging technique of Rayleigh scattering to ultracentrifuge tubes containing separated lipoproteins, particle concentrations at differing diameters can be calculated. This thesis primarily goes through the time consuming task of optimizing the innovative Rayleigh scattering system so that correct quantitative estimations can be performed. Constrained by Rayleigh theory and system limitations, lipoproteins of 15 nm to 35 nm are focused upon. By doing so, previously disguised data in regards to lipoprotein subclasses is exposed. Lipoprotein diameters are estimated from Rayleigh imaged serum profiles and the estimations are confirmed through secondary size analysis achieved by dynamic light scattering instrumentation. In addition to Rayleigh optimization, a strategy for quantifying the ultracentrifuged lipoprotein particles using the recently applied scattering technique is explained in detail providing a foundation for further research. In regards to all feasibility studies presented within this thesis, much success was achieved in furthering quantitation efforts in lipoprotein density profiling.

Ultracentrifugation and imaging techniques of human blood serum are precise and information-rich methods for obtaining information about an individual’s lipoprotein particle content. The information derived from lipoprotein separations via an ultracentrifuge plays a key role in the area of preventative medicine in regards to atherosclerosis. Two of the most critical lipoprotein characteristics, diameter and density, are well preserved with the proper isopycnic gradient. Currently, lipoprotein particles are stained, ultracentrifuged, and profiled through image analysis. This particular technique is helpful in determining particle density and can be correlated loosely with particle concentration. The need to completely quantify lipoprotein concentrations is imperative in assessing risk factors accurately. Light scattering techniques, primarily Rayleigh scattering, are applied to density separated serum samples in resulting in improved qualitative data with progress in quantitative measurements through imaging alone. The Rayleigh theory dictates that a particle’s scattered intensity is based upon the incident intensity, the particle’s diameter, and the particle’s concentration when strict criteria are met within the sample and imaging apparatus. Applying this innovative imaging technique of Rayleigh scattering to ultracentrifuge tubes containing separated lipoproteins, particle concentrations at differing diameters can be calculated. This thesis primarily goes through the time consuming task of optimizing the innovative Rayleigh scattering system so that correct quantitative estimations can be performed. Constrained by Rayleigh theory and system limitations, lipoproteins of 15 nm to 35 nm are focused upon. By doing so, previously disguised data in regards to lipoprotein subclasses is exposed. Lipoprotein diameters are estimated from Rayleigh imaged serum profiles and the estimations are confirmed through secondary size analysis achieved by dynamic light scattering instrumentation. In addition to Rayleigh optimization, a strategy for quantifying the ultracentrifuged lipoprotein particles using the recently applied scattering technique is explained in detail providing a foundation for further research. In regards to all feasibility studies presented within this thesis, much success was achieved in furthering quantitation efforts in lipoprotein density profiling.

The development to date of a diode-laser based velocimeter providing point-velocitymeasurements in unseeded flows using molecular Rayleigh scattering is discussed. The velocimeter is based on modulated filtered Rayleigh scattering (MFRS), a novel variation of filtered Rayleigh scattering (FRS), utilizing modulated absorption spectroscopy techniques to detect a strong absorption of a relatively weak Rayleigh scattered signal. A rubidium (Rb) vapor filter is used to provide the relatively strong absorption; alkali metal vapors have a high optical depth at modest vapor pressures, and their narrow linewidth is ideally suited for high-resolution velocimetry. Semiconductor diode lasers are used to generate the relatively weak Rayleigh scattered signal; due to their compact, rugged construction diode lasers are ideally suited for the environmental extremes encountered in many experiments. The MFRS technique utilizes the frequency-tuning capability of diode lasers to implement a homodyne detection scheme using lock-in amplifiers. The optical frequency of the diode-based laser system used to interrogate the flow is rapidly modulated about a reference frequency in the D₂-line of Rb. The frequency modulation is imposed on the Rayleigh scattered light that is collected from the probe volume in the flow under investigation. The collected frequency modulating Rayleigh scattered light is transmitted through a Rb vapor filter before being detected. The detected modulated absorption signal is fed to two lock-in amplifers synchronized with the modulation frequency of the source laser. High levels of background rejection are attained since the lock-ins are both frequency and phase selective. The two lock-in amplifiers extract different Fourier components of the detected modulated absorption signal, which are ratioed to provide an intensity normalized frequency dependent signal from a single detector. A Doppler frequency shift in the collected Rayleigh scattered light due to a change in the velocity of the flow under investigation results in a change in the detected modulated absorption signal. This change in the detected signal provides a quantifiable measure of the Doppler frequency shift, and hence the velocity in the probe volume, provided that the laser source exhibits acceptable levels of frequency stability (determined by the magnitude of the velocities being measured). An extended cavity diode laser (ECDL) in the Littrow configuration provides frequency tunable, relatively narrow-linewidth lasing for the MFRS velocimeter. Frequency stabilization of the ECDL is provided by a proportional-integral-differential (PID) controller based on an error signal in the reference arm of the experiment. The optical power of the Littrow laser source is amplified by an antireflection coated (AR coated) broad stripe diode laser. The single-mode, frequency-modulatable, frequency-stable O(50 mW) of optical power provided by this extended cavity diode laser master oscillator power amplifier (ECDL-MOPA) system provided sufficient scattering signal from a condensing jet of CO₂ to implement the MFRS technique in the frequency-locked mode of operation.