Increased efficiency and reduced emissions from gas turbine (GT) engines are of consistently growing concern for the current gas turbine community and for the political environment. GT engines commonly produce undesirable emissions such as Carbon Monoxide (CO), Carbon Dioxide (CO₂), Nitric Oxides (NO_x), and Unburned Hydrocarbons (UHC), which all pose various threats to the environment. Lean premixed combustion of hydrogen provides a potential solution to these concerns. A key component of successful lean hydrogen combustion is the fuel-air mixer. A facility and methodology for the evaluation of such a hydrogen-air mixer is developed and discussed in this thesis. The facility developed utilizes three experimental techniques: Mie scattering flow visualization, schlieren flow visualization, and Laser Doppler Velocimetry (LDV) to characterize and evaluate mixer performance. Results from the two flow visualization experiments illustrate the effectiveness of the established facility. The results from the Mie scattering experiment are post processed and overlaid on CFD predictions of mixer performance and many similarities are found. Capability of the LDV to measure two components of mean velocity is also demonstrated. / Master of Science

Remote sensing is the collection of information about an object from a distance without physically being in contact with it. The type of remote sensing of interest here is in the form of digital images of water bodies acquired by satellite. The advantage over traditional sampling techniques is that data can be gathered quickly over large ranges, and be available for immediate analysis. Remote sensing is a powerful technique for the monitoring of water bodies. To interpret the remotely sensed data, however, knowledge of the optical properties of the water constituents is needed. One of the most important of these is the volume scattering function, which describes the angular distribution of light scattered by a sample. This thesis presents the first measurements of volume scattering functions for Australian waters. Measurements were made on around 40 different samples taken from several locations in the Gippsland lakes and the Great Barrier Reef. The measurements were made by modifying an existing static light scattering spectrometer in order to accurately measure the volume scattering functions. The development of the apparatus, its calibration and automation, and the application of a complex series of post-acquisition data corrections, are all discussed. In order to extrapolate the data over the full angular range, the data was analysed using theoretical curves calculated for multi-modal size distributions using Mie light scattering theory applied to each data set. From the Mie fits the scattering and backscattering coefficients were calculated. These were compared with scattering coefficients measured using in situ sensors ac-9 and Hydroscat-6, and with values from the literature. The effect of chlorophyll a concentrations on the scattering coefficients was examined, and a brief investigation of the polarisation properties of the samples was also undertaken. Finally the angular effects on the relationship between the backscattering coefficient and the volume scattering function were investigated. This is important as in situ backscattering sensors often assume that measuring at a single fixed-angle is a good approximation for calculating the backscattering coefficient. This assumption is tested, and the optimal measurement angle determined.

No description available.

Microparticle experiments conducted using a newly commissioned quadrupole ion trap (QIT) are reported. Single polystyrene microparticles are confined using three dimensional electrodynamic quadrupole fields and characterised by their fluorescence emission and secular frequency measurements. The advantages of this confinement technique are that single particle properties can be measured free from ensemble averaging effects and unperturbed by solvents and (or) substrates. (For complete abstract open document)

Thesis (Ph.D.)--University of Melbourne, School of Chemistry, 2007. / Typescript. Includes bibliographical references (leaves 103-109).

Une crème solaire, ayant pour objectif de filtrer les UV, est un système complexe, à plusieurs phases, contenant deux types de filtres : des filtres dits chimiques - c'est-à-dire des molécules absorbantes - et des réflecteurs (comme le TiO2), protégeant par diffusion de la lumière. Afin d'évaluer l'efficacité des produits, des mesures d'indice de protection (IP ou SPF) existent ; la crème est placée in vivo sur différents phénotypes de peau ou in vitro sur un support plastique en PMMA.Afin de modéliser la protection solaire, nous avons cherché à connaitre la répartition de la crème sur son support. Nous avons pour cela utilisé l'OCT (Tomographie à Cohérence Optique) avec un support plastique métallisé, permettant d'améliorer le contraste des images.Ceci nous a alors permis, en connaissant les paramètres des différents filtres chimiques ou particulaires, de modéliser la transmission de la crème sur son support la peau ou le PMMA. Nous avons pour cela utilisé la méthode différentielle, une méthode de calcul de diffusion de la lumière permettant de traiter une structure bidimensionnelle.Nous avons alors pu comparer nos résultats de calcul avec des mesures de protection, étudier l'influence de quelques caractéristiques des particules comme la taille ou le matériau utilisé, ou bien encore évaluer l'effet de l'hydratation de la couche la plus externe de la peau sur la protection solaire. Nous avons par ailleurs cherché à améliorer la vitesse et le champ d'application des calculs en comparant les résultats obtenus par la méthode différentielle avec d'autres modèles (diffusion de la lumière par des tiges ou théorie de Mie). / Sunscreens, an emulsion of several phases, are used as UV filters in order to protect people from sun damages. Filters can be divided in two types: the chemical ones which are organic molecules that absorb selectively ultraviolet light and the physical ones (such as TiO2) which are inorganic particles that scatter and may absorb some of the UV radiation. The sunscreen quality is given by the sun protection factor (SPF), measured in vivo. In order to avoid long and complicated tests, a quick and simple in vitro method, using a plastic substrate, has been established, which gives an approximation of the SPF. In order to model the sunscreen protection, we had to evaluate the sunscreen distribution. We used an OCT (for Optical Coherence Tomography) device, after having spread a metallic thin on the substrate before applying the sunscreen. Theses images helped us to model the cream transmission on the skin or the plastic substrate, using the differential method which can calculate the scattering of light through a 2D structure.We then compared our results to measurements, but also studied the impact of several particles specifications, such as the size or the material of the particle, or study the effect of the skin hydration on the UV protection.Furthermore, we have compared our results to other calculation methods (Mie scattering or scattering by a set of parallel cylinders) in order to improve the calculation time and try a 3D-method.

This paper investigated the effects of swirl number and momentum ratio on the atomization and mixing performance of Swirl-Venturi Lean Direct Injection technology. Mie scattering of liquid water, was used to identify the location of water droplets in a cross section of the injector spray. Experiments were performed with three air swirlers with vane angles of 45, 52 and 60 degrees. The swirl number varied from 0.58 to 1.0 and air-to-liquid ratios from 15.8 to 35.6. A transition was observed in the liquid spray distribution for the 52 degree case, which unexpectedly produced twice as much signal than the 45 and 60 degree cases. The main cause of this increased signal may be due to instabilities in the flow when transitioning from low to high swirl states. The results from investigation of swirl number it was found that the spray pattern for is sensitive to swirl intensity. Two flow states were observed for a lower and higher swirl flow as well as a transition state that occurred with the lower swirl state. This work may aid in the specific inquiry of physical mechanisms relating to the effect of flow states on spray distribution. It is found that improved atomization and mixing performance are a result of increase in swirl number.

Patients with pancreatic cancer in metastasis rarely survive, thus the need for diagnostic tools for early stage detection. Current techniques such as ELISA and SPR are complex and expensive and cannot detect cancer in its early stages. Cancer Antigen 242 (CA 242) is a potential protein biomarker of pancreatic cancer with high sensitivity and specificity. This thesis presents a negative Dielectrophoresis (DEP) based method of detecting pancreatic cancer protein biomarker CA 242 in serum. A spectrum of concentration levels was generated with a cut off level 20 U/mL using a transduction mechanism with negative DEP spectroscopy, light scattering, and image processing. This was a fast and cost-effective method to diagnose early stage pancreatic cancer. This thesis also presents the design and simulation of an electrode modified to increase the electric field gradient with reduced heat generation and a concentration prediction model to predict concentrations from the generated spectrum of experiments.

The aim of the presented work is to investigate the angle-resolved scattering characteristics of biological nano- and micro-scaled cell structures. The scattering results of cellular structures were compared to measurements of ideal spherical nano- and micro-particles. A monolayer of mouse fibroblasts L929 cells was cultivated in a Dulbecco's Modified Eagle Medium (DMEM) in a standard 24 well cell culture plate. The system allows an in situ measurement directly in the standard cell culture plate and a contaminant-free investigation of the viability of the cell cultures. Of particular interest was whether changes in the tumor characteristics occur in necrosis or other cell-harming effects. Because of the size ratios between wavelength and the scattering particles, all observations were investigated using Mie scattering theory. A setup for reliable measurements was developed and the scattered angle dependent intensity obtained was compared with simulated scattering characteristics. A homemade supercontinuum (SC) light source was filtered by an optical bandpass filter with a central wavelength of 500 nm. The scattered portion of the pulsed SC light behind the sample was recorded in a time-resolved manner at defined angles. A specimen holder adapted to standard cell culture plates allows detection of scattered radiation at angles between ±80° without angle-dependent Fresnel reflection losses and a Snell’s law bending of the propagation direction. Finally, the system was tested to detect structural changes of mouse fibroblast L929 cells before and after poisoning the cells with the cell detergent Triton X100 and the data clearly shows changes in the scattering characteristics when the cells were destroyed.

The living body tissues consist of cells which dimensions are bigger than a wavelength of visible light. Therefore a Mie scattering of reflected of backscaterred light occurs and different polarization states arise. The changes of polarization state due to the multiple scattering of light in the biological cellular tissues allow measure the aging of biological tissue. The reflected or backscattered polarized laser light exhibits multiple scattering on the sample surface and in its subsurface area.