The objective of this Thesis is to design a scan lens for a long wave infrared laser marking system. The system is comprised of a laser source emitting a collimated beam coupled with a 14mm aperture dual axis galvanometer scanning system capable of scanning a range ± 11° (mechanical). Multiple scan lens options will be considered. Each scan lens will be optimized to maximize peak irradiance and operate at, or near, the diffraction limit over a 210x110 mm 'plus' shaped field. Unintended distortion evident in some lens designs and will be compensated for by developing equations that allowed the proprietary imaging algorithm to adjust the angle of the scanning mirror appropriately to achieve an undistorted image. The accuracy of the distortion correction will be within 1% of the shortest image dimension. Commercially available scan lenses are designed for generic scanning systems with no apriori knowledge of the imaging model and are typically available in arbitrary focal length increments. As a result, use of off the shelf scan lenses result in sub-optimal performance. This thesis presents background information on galvanometer based scanning systems followed by a review of classical scan lenses. The imaging application and systems constraints for the marking system are defined. The steps taken to design and optimize a conventional, aspheric, and F-Theta scan lens are described, and their performances are compared with respect to the design requirements. The Conventional scan lens coupled with a distortion correction equation was found to offer the best performance to cost ratio and was deemed the most appropriate lens for the marking system.

A systematic examination of 1836 images of the sky constructed from scans made by the Infrared Astronomical Satellite has resulted in the detection of 466 objects which are shown to be in Earth orbit. Analysis of the spatial and size distribution and thermal properties of these objects, which may include payloads, rocket bodies and debris particles, is being conducted as one step in a feasibility study for space -based debris detection technologies.

This Thesis contains two parts. Part I details my work on KMOS, a new instrument for the VLT and Part II details my research on scaling relations for the massive galaxy cluster MS0451.6-0305. Part I: The K-Band Multi-Object Spectrograph (KMOS) is a new near infra-red (NIR) instru- ment to be installed at the Very Large Telescope (VLT). KMOS is capable of spatially resolved kinematics via 24 deployable integral field units (IFUs), each with a 2.8′′ field of view. I describe my contribution to the construction and optical characterisation of the spectrograph modules and instrument as a whole. Part II: GMOS-N spectroscopy has been used to obtain velocity dispersions (σ) and archival HST photometry has been used to determine the effective radii (Re) & average surface brightnesses within Re (⟨I⟩e) of 26 confirmed cluster members of MS0451.6-0305 at z = 0.55. The Kormendy Relation, Faber-Jackson Relation and Fundamental Plane have been produced for the cluster and have been compared to the results for a local reference sample in Coma. GMOS-N g′ and r′ band photometry has also been used to produce a Colour-Magnitude Relation for MS0451.6-0305. It is found that the KR and FJR disagree at the 2.1σ level with respect to luminosity evolution since z = 0.55. When correcting for size-evolution (SE), the magnitude offsets agree and are consistent with passive evolution of the galaxy stellar populations from a single burst of star formation 9.8+4.5-1.7 Gyrs ago or z = 1.7+∞-0.6. The median offset in the FP relation for the SE corrected data is also consistent with this formation epoch. Evidence is found for the evolution of the FP tilt in MS0451.6-0305, where it is shown to be steeper than that of the Coma FP, when expressed as a relation between galaxy mass and M/L.

Gases at satisfactory pressures fluoresce in the presence of radio frequency radiation (6). Such fluorescent gases have been used to probe fields of radio frequency oscillation and their emission spectra have been recorded and studied. Ions with multiple charges also exist in these gases, (6). In 1941 Oliver (12) observed the fluorescence of an isobutane- isobutene gaseous mix flowing to a pump through a glass tube which was wrapped by a spiral antenna of a sevenmegacycle transmitter. A white deposit was noticed at a bend in the tubing on the pump side of the fluorescing section of the gas (12, p. 8). In 1957 Blacknall (3) studied the fluorescence and reaction products of propylene in the antenna region of sevenmega- cycle radiation, The oscillator employed by Blacknall was an ARC-5/T-22 military surplus transmitter of range 7.00 to 9.10 megacycles, which he operated at 7.00 megacycles. Blacknall observed a drop in pressure and the formation of a brown deposit in the region of the coil. Blacknall did not report an analysis of this product. In 1959 Armstrong (1) repeated Blacknall's experiments and modified Blacknall's apparatus into an improved design. He also performed an analysis on Blacknall's product. Blacknall used a vertical open-end mercurial manometer with which to measure pressure in his system and as a result introduced mercury vapor into his system. Armstrong tried to minimize the amount of mercury introduced by covering his manometric mercury with a layer of octyl sebacate, "octoil". Armstrong used a spiral-would antenna wrapped around his reaction vessel and reported the formation of spiral brown rings coincident with the copper wire of the antenna. There was a white product deposited in a spiral interlaced with the spiral of dark brown material. No definite identification was reported by Armstrong other than reporting, his solid material as isotactic polypropylene. Other work on electrodeless discharge of organic chemicals has been done in 1960 by Durward Smith and William Smith (13), in 1961 by Jimmie McCarty (10), and in 1963-64 by David Flinn (4).

Doctor of Philosophy / Department of Biological and Agricultural Engineering / Wenqiao Yuan / Biodiesel production and utilization has been increasing rapidly worldwide in recent years. A main challenge in the commercialization and public acceptance of biodiesel is its quality control. This work reports the use of infrared spectroscopy to monitor biodiesel quality through the development of models to predict (1) the blending level of biodiesel in biodiesel-diesel mixtures, (2) the fatty acid profile of biodiesel fuels derived from various lipids, and (3) the concentration of most common impurities present in biodiesel including water, glycerol, methanol and triglycerides. Regressions based on near-infrared (NIR) spectroscopy were developed for relatively inexpensive and rapid on-line measurement of the concentration and specific gravity of biodiesel-diesel blends. Methyl esters of five different oils—soybean oil, canola oil, palm oil, waste cooking oil, and coconut oil—and two different brands of commercial-grade No. 2 on-highway diesel and one brand of off-road No. 2 diesel were used in the calibration and validation processes. The predicted concentration and specific gravity of the biodiesel-diesel blends were compared with the actual values. The maximum and average root-mean-square errors of prediction (RMSEP) of biodiesel concentration were 5.2% and 2.9%, respectively, from the biodiesel type-specific regression. For the general regression, the RMSEP were 3.2% and 0.002 for biodiesel concentration and specific gravity predictions, respectively. Five different models were developed to determine the concentration of methyl palmitate (C16:0), methyl stearate (C18:0), methyl oleate (C18:1), methyl linoleate (C18:2), and methyl linolenate (18:3) present in biodiesel. Using the NIR range a set of models based on four different types of biodiesel was developed. The maximum RMSEP was 0.553% when the models were validated with biodiesel samples that were used in the calibration, however, prediction accuracy of the model under external samples was poor, therefore, a new set of models was proposed. For this case, six different types of biodiesel were used. The models developed for C18:1, C18:2 and C18:3 presented good accuracy on prediction. However, for C16:0 and C18:0, additional work was necessary to reach reasonable accuracy in prediction. Three sub models for specific ranges of concentration (low, medium, and high) were developed. The RMSEP was reduced from 2.98% to 1.51% for the C16:0 and from 2.33% to 0.56% for C18:0, when the sub-models were validated under internal and external samples. Similar procedures were followed to develop regression models based on mid infrared (MIR) spectra. The RMSEP for C16:0, C18:0, C18:1, C18:2, and C18:3 were 0.83%, 0.37%, 1.45%, 1.59%, and 0.84%, respectively. Predictions using MIR spectroscopy models were better than those obtained with NIR spectroscopy models for the C16:0 and C18:0 models. The most common impurities present in biodiesel from production processes, including methanol, free glycerol, triglycerides, and water, were determined by infrared methods using NIR and MIR spectra and partial least square regression (PLSR) methods. The models were developed in two different approaches, one was when a single impurity was present and the other was when all impurities were present. In the single impurity models, the maximum RMSEP obtained in the NIR and MIR models were 647 mg kg[superscript]-1 and 206 mg kg[superscript]-1, respectively. The models for methanol, glycerol, and water performed better using the NIR data. For the triglycerides model, MIR worked better. Only NIR data were used to develop the models for samples with all impurities. Data pre-treatment (Savitzky-Golay second derivative) was necessary to achieve reasonable accuracy in the predictions in this type of models. The maximum RMSEP was 932 mg kg[superscript]-1 presented in the model for triglycerides. The best performance was obtained in the model developed to predict methanol concentration in biodiesel with RMSEP of 177 mg kg[superscript]-1 when all listed impurities were presented. The feasibility of using NIR and MIR spectroscopy to monitor biodiesel quality was demonstrated in this work. The developed method was accurate, rapid, convenient, yet inexpensive to determine some important characteristics of biodiesel, such as biodiesel blending level in biodiesel-diesel mixtures, the fatty acid profile of biodiesel, and impurities present in the fuel.

Call number: LD2668 .T4 1957 K63 / Master of Science

No description available.

OH-stretching spectra of various vapour phase species were recorded to investigate hydrogen bonding. The species studied include 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, acetylacetone, hexafluoroacetylacetone and the complex formed in the heterogeneous mixture of methanol and trimethylamine. The spectra range from the infrared, near infrared to visible wavelengths. The main focus of this study is in the near infrared region, in which the OH-stretching overtones are dominant. The near infrared and visible spectrum of formic acid has been recorded to investigate coupling across bonds, specifically a resonance occurring between OH- and CH-stretching vibrations. The same resonance was also observed in the spectrum of 1,2-ethanediol. The spectra of deuterated isotopomers of formic acid and 1,2-ethanediol were recorded to experimentally verify the resonance. The inherently weak nature of the vibrational overtone transitions required sensitive spectroscopic techniques to observe the spectra. The spectra were recorded with conventional long path length absorption spectroscopy and intracavity laser photoacoustic spectroscopy. Anharmonic oscillator local mode calculations of the OH-stretching transitions were performed to simulate the observed spectra. These calculations require calculation of potential energy surfaces and dipole moment functions. Simulated spectra obtained with highly correlated ab initio methods and large basis sets have yielded the best agreement with observation.

Thesis (Ph. D.)--Texas Christian University, 2007. / Title from dissertation title page (viewed Dec. 10, 2007). Includes abstract. Includes bibliographical references.

<p>In this project we have used Fourier transform infrared spectroscopy to study the photoresponse of two different types of quantum dot-in-a-well infrared photodetectors (DWELL QDIPs). The basic task was to compare the photoresponse of these two detectors, and to study the influence of external resonant laser pumping on the photoresponse. Series of measurements were done at 77K. In the first measurements we investigated the photoresponse for different applied voltages at 77K. </p><p>In a second run of experiments, we used a 1064 nm infrared semiconductor laser to resonantly </p><p>pump the fundamental transition of the quantum dots. The results show that by using this </p><p>additional illumination the photoresponse was dramatically increased by creating additional </p><p>charge carriers in the quantum dots. This could be used to increase the sensitivity of infrared </p><p>detectors based on QDs.</p>