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The SNO+ experiment will be the SNO detector filled with a neodymium-loaded liquid scintillator instead of heavy water. SNO+ will be used to detect neutrinos of much lower energy. Also, SNO+ will conduct a search for neutrinoless double beta decay with Nd-150. The Nd-loaded scintillator in SNO+ will be made from linear alkylbenzene (LAB). Both the LAB solvent and the Nd loading are new developments. The optical properties of this scintillator and information about radioactive backgrounds should be studied. A calibration source known as the scintillator bucket was deployed in the water-filled SNO detector in order to study some optical properties of Nd-loaded scintillator, raw LAB scintillator and distilled LAB scintillator. Using a neutron source attached to the bucket to produce events with known energy, with a model of the scintillator bucket simulated by an analysis tool called RAT, the light yield of the scintillator could be determined by comparing data measurements with simulations. This allowed the light yield, one of the main optical properties of the scintillator, to be measured and that value to be corrected in the Monte Carlo. The bucket was deployed both at the centre of the detector and at the bottom. After subtracting backgrounds from radon introduced in the scintillator during preparation and filling, constraints on the amount of Po-210 were obtained. Estimates on the K-40 content of the Nd-loaded scintillator were obtained by analyzing the radon-subtracted background spectra. By comparing the background spectra with the bucket deployed at the bottom of the acrylic vessel with spectra from the bucket at the centre, it was possible to estimate the K-40 content of the acrylic vessel. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2010-09-22 11:55:44.351

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The chiroptical properties of isotropic solutions, cholesteric liquid crystals and solid films prepared from selected cellulose derivatives are investigated by optical rotary dispersion (ORD) and circular dichroism (CD). Optical activity from intrinsic molecular dissymmetry, polymer conformation and cholesteric reflection properties are considered. / The chiroptical properties of cholesteric liquid crystals are interpreted according to deVries' theory. Lyotropic liquid crystalline phases formed by (hydroxypropyl)cellulose in methanol display anomalously high optical rotation at low wavelengths. The anomalies disappear on the addition of a dipolar aprotic solvent, and are absent for the ethyl ether derivative of the polymer, indicating a chiral hydrogen bonded structure is contributing to the optical activity. / Investigation of the chiroptical properties of cellulosics by circular dichroism requires the presence of a suitable chromophore, either as a chain substituent or as an added dye. Congo red exhibits induced optical activity in dilute aqueous solutions of methylcellulose and cellulose oligomers, providing evidence for the presence of a helical conformation. CD spectra of two new biphenyl derivatives also exhibit exciton splitting characteristic of a helical arrangement of chromophores. Conformational dissymmetry is not indicated in spectra of cellulose acetate although the sign of carbonyl CD band is solvent dependent. The sign of this band is interpreted in terms of the orientation of the ester substituent relative to the anhydroglucose ring. Congo red, bound in cholesteric cellulose films prepared by the deacetylation of cellulose acetate cast from mesophase solution, shows induced optical activity which, in this case, reflects the cholesteric nature of the matrix. Similar results for cellulose gels regenerated from LiCl/N,N-dimethylacetamide solution indicate that cellulose adopts a supramolecular helicoidal arrangement on slow precipitation from solution. / The optical properties of the thermotropic cholesteric liquid crystalline phase formed by a new cellulose derivative, (ethoxypropyl)cellulose, are examined by circular reflectivity measurements. / The cholesteric reflection properties of mesophase solutions of cellulose acetate in trifluoroacetic acid are characterized. The polymer undergoes rapid trifluoroacetylation in this solvent and the presence of trifluoroacetate substituents alters the handedness and the magnitude of the pitch. Although the pitch is sensitive to the nature of achiral substituents, it is not influenced by the addition of chiral solvents. (Abstract shortened with permission of author.)

Power utilities around the world are now in the practice of installing fiber optic cables on their high voltage transmission networks. These high-speed communication channels can, not only transmit data needed for utility operation, but the unused fiber capacity may also be rented to others for communication. All dielectric self-supporting (ADSS) fiber optic cable appears to be the fiber optic cable most frequently installed by power utilities as it is more economical, has a larger fiber capacity and may be installed on a transmission line without de-energization. When installed however, ADSS fiber optic cable does undergo some degree of degradation caused either by armor rod corona at the towers or dry-band arcing. A comprehensive literature survey regarding both phenomena is presented in this study, as well as current mitigation techniques. Different models that describe the process of dry-band arcing are discussed, including those where an equivalent circuit is used to represent a polluted fiber optic cable in a high voltage environment. An implementation of this model on a MATLAB® based computer program is used to evaluate parameters such as leakage current magnitude, which may be used to predict the possibility of dry-band arcing. This leakage current is also compared to simulated results that were generated using a power system analysis program called Alternate Transients Program (ATP). A finite element package, FEMLAB®, was used to model the experimental system, prior to construction. A single-phase transmission line with an accompanying fiber optic cable was constructed. The leakage current magnitude obtained from this experiment was subsequently compared to those obtained from the simulations. These leakage current comparisons are discussed and explained in view of limitations with the theoretical models and refinements in the experimental techniques employed. The results clearly indicate that physical parameters like pollution severity, system voltage, length of span and the point of attachment of the ADSS fiber optic cable in the tower play a significant role in the determination of leakage currents induced on the outer sheath of the cable. These induced currents result in the formation of 'dry bands', due to joule heating, and this could result in arcing activity that erodes the fiber optic cable. / Thesis (M.Sc.Eng)-University of Natal, Durban, 2003.

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This thesis concerns experimental studies of nanocrystalline tungsten trioxide thin films. Functional properties of WO3 have interesting applications in research areas connected to energy efficiency and green nanotechnology. The studies in this thesis are focused on characterization of fundamental electronic and optical properties in the semiconducting transition metal oxide WO3. The thesis includes also applied studies of photocatalytic and photoelectrochemical properties of the material.     All nanocrystalline WO3 thin films were prepared using DC magnetron sputtering. It was found that structures like hexagonal and triclinic phase with different properties can be produced with sputtering technique. Thin film deposition has been performed using different process parameters with emphasis on sputter pressure and films that mainly consist of monoclinic γ-phase, with small contributions of ε-phase. Changes in the pressure are shown to affect the number of oxygen vacancies in the WO3 thin film, with close to stoichiometric WO3 formed at high pressures (30 mTorr), and slightly sub-stochiometric WO3-x, x = 0.005 at lower pressures (10 mTorr). Both stoichiometric and sub-stoichiometric thin films have been characterized by several structural, optical and electronic techniques.    The electronic structure and especially band gap states have been explored and optical properties of WO3 and WO3-x have been studied in detail. The band gap has been determined to be in the range 2.7-2.9 eV. Absorption due to polaron absorption (W5+  -W6+), oxygen vacancy sites (Vo -W6+), and due to differently charged oxygen vacancy states in the band gap have been determined by spectrophotometry and photoluminescence spectroscopy, in good agreement with resonant inelastic x-ray spectroscopy and theoretical calculations. The density of electronic states in the band gap was determined from cyclic voltammetry measurements, which correlate with O vacancy concentration as compared with near infrared absorption.      By combining different experimental methods a thorough characterization of the band gap states have been possible and this opens up the opportunity to tailor the WO3 functionalities. WO3 has been shown to be visible active photocatalyst, and a promising electrode material as inferred from photo-oxidation and water splitting measurements, respectively. Links between device performance in photoelectrochemical experiments, charge transport and the electronic structure have been elucidated.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.

Thesis (Ph. D.)--Texas A & M University, 1993. / Vita. Includes bibliographical references (p. 204-208).