Thesis (Ph. D.)--University of Texas at Dallas, 2006. / Includes vita. Includes bibliographical references (leaves 173-178).

OSIRIS, a Canadian built instrument on-board the Swedish-led remote sensing satellite, Odin, consists in part of three single lens imagers that measure near infrared light from atmospheric scattering and emission. A full calibration of the imaging system is required to remove all instrument dependent effects that modify the observations. <p>This work presents the characterization and calibration of the OSIRIS imaging system in an attempt to produce observations that are instrument independent measurements of the atmospheric brightness. The required product is the number of photons per second emitted, or scattered, from the atmosphere that are within the sampling wavelength range and incident on the detector area in the instrument field of view. <p>A major portion of the present work involves understanding the dark current production mechanisms and the development of a technique to characterize the dark current and manufacturer imposed electronic offsets. It is demonstrated that with a current set of dark calibration images, the developed algorithm effectively removes the dark current and electronic offsets over a wide operating temperature range. The relative calibration of pixels is presented in terms of the electronic gain, or flat field response, and the angular look direction. It is apparent that a change in the relative pixel gain occurred between pre-flight calibration and the first in-flight images. However, it is shown that with a recalculation of the flat field response using in-flight images, an acceptable gain calibration is obtained. The angular look direction of the pixels is determined from the results of two separate in-flight experiments. The characterization and removal of the stray light signal is shown to be effective. <p>Finally, the absolute calibration of the instrument is presented. While several issues remain to be addressed, the comparison with a simple atmospheric brightness model provides a first order verification of the results.

OSIRIS, a Canadian built instrument on-board the Swedish-led remote sensing satellite, Odin, consists in part of three single lens imagers that measure near infrared light from atmospheric scattering and emission. A full calibration of the imaging system is required to remove all instrument dependent effects that modify the observations. <p>This work presents the characterization and calibration of the OSIRIS imaging system in an attempt to produce observations that are instrument independent measurements of the atmospheric brightness. The required product is the number of photons per second emitted, or scattered, from the atmosphere that are within the sampling wavelength range and incident on the detector area in the instrument field of view. <p>A major portion of the present work involves understanding the dark current production mechanisms and the development of a technique to characterize the dark current and manufacturer imposed electronic offsets. It is demonstrated that with a current set of dark calibration images, the developed algorithm effectively removes the dark current and electronic offsets over a wide operating temperature range. The relative calibration of pixels is presented in terms of the electronic gain, or flat field response, and the angular look direction. It is apparent that a change in the relative pixel gain occurred between pre-flight calibration and the first in-flight images. However, it is shown that with a recalculation of the flat field response using in-flight images, an acceptable gain calibration is obtained. The angular look direction of the pixels is determined from the results of two separate in-flight experiments. The characterization and removal of the stray light signal is shown to be effective. <p>Finally, the absolute calibration of the instrument is presented. While several issues remain to be addressed, the comparison with a simple atmospheric brightness model provides a first order verification of the results.

Infrared microspectroscopy has been used to survey Alzheimer’s diseased brain tissue from a transgenic mouse model of the disease. Alzheimer’s disease is the leading cause of dementia among the elderly and is characterized by β-amyloid plaque deposition,neurofibrillary tangles, inflammation, and disturbed energy metabolism in the brain. Both the TgCRND8 and Tg19959 mouse models of the disease develop Alzheimer’s disease pathology beginning at approximately 3 months of age. Infrared microspectroscopy allows analysis of untreated, flash frozen tissue samples, at micron level spatial resolution, and was used in this study to examine creatine deposits in the Alzheimer’s diseased brain. Creatine is central to cellular energetics and plays an important role in proper brain function. The hippocampi of 7 pairs of transgenic mice and their littermate controls were mapped using infrared microspectroscopy and the results were analyzed for creatine levels and levels of β-sheet, indicative of the presence of β-amyloid plaques. Creatine was found to be focally elevated in the transgenic mice, as compared to their littermate controls but was not co-localized with β-amyloid plaques. Further surveys of serial sections from one transgenic mouse showed the 3-dimensional distribution of creatine within the sample. Focally elevated creatine may be a marker of the disease process, indicative of disturbed energy metabolism or inflammatory response to the disease progression. / February 2008

New, rapid techniques to quantify the different pools of soil organic matter (SOM) are needed to improve our understanding of the dynamics and spatio-temporal variability of SOM in terrestrial ecosystems. In this study, total organic carbon (TOC) and oxidizable organic carbon (OCWB) fraction were calibrated and predicted by mid- and near-DRIFT spectroscopy in combination with partial least squares (PLS) regression method. PLS regression is a multivariate calibration method that can decompose spectral data (X) and soil property data (Y) into a new smaller set of latent variables and their scores that best describe all the variance in the data. Oxidizable organic carbon content was measured by a modified Walkley-Black method, and total organic carbon was measured by the carbon analyzer. The floodplain and Blackland Prairie soils in Texas were used for prediction of TOC and OCWB using mid- and near-DRIFT spectroscopy. Floodplain soil is mainly composed of quartz and kaolinite, whereas Blackland Prairie soils contain high concentrations of smectitic clays and low to high concentrations of carbonate minerals. The total organic carbon of 68 soil samples from two Texas sites varied between 0.19 and 4.36 wt.% C, and the oxidizable organic carbon of 26 samples from floodplain soils was in the range of 0.05 to 1.33 wt.% C. TOC and OCWB of soil were successfully calibrated and predicted by the PLS regression method using mid- and near-DRIFT spectroscopy. The correlation using mid-IR spectra for TOC (r = 0.96, RMSEV = 0.32 for calibration; r = 0.93, RMSEP = 0.44 for prediction) was about the same as the near-IR result (r = 0.95, RMSEV = 0.37; r = 0.93, RMSEP = 0.42). Therefore, we can also use mid-infrared region for quantification of total organic carbon in soils. The PLS1 regression model (r = 0.92) for prediction of OCWB using mid-IR spectra was more accurate than the PLS2 regression model (r = 0.90). PLS models showed better correlation with spectral data than the univariate least square regression method(r = 0.83) with TOC measured by the carbon analyzer. This study shows that the partial least squares (PLS1) method using mid-and near-IR spectra of neat soil samples can be used to predict both total organic carbon and oxidizable carbon fraction as a fast and routine quantitative method.

Thesis (MSc)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis--Cambridge. / Typescript (carbon) with ms. corrections. Includes bibliographical references.

Thesis (Ph. D.)--University of Michigan, 1933. / From Physical review, v. 42, December 1, 1932.

Thesis (M.S. in Combat Systems Technology)--Naval Postgraduate School, December 2003. / Thesis advisor(s): Alfred W. Cooper, Gamani Karunasiri. Includes bibliographical references (p. 83-84). Also available online.

Thesis (M. Sc.)--University of Hong Kong, 1973. / Typewritten.