This thesis is an investigation of the relative differences of acid ionization constants and ion mobility in D2O versus H2O under hydrothermal conditions, for acetic acid and phosphoric acid. Values of specific conductivity were measured for each acid in H2O and D2O, as well as for a series of strong electrolytes using a high-temperature high-pressure AC conductivity flow cell that was originally designed at the University of Delaware. The Fuoss-Hsai-Fernández-Prini (FHFP) equation was fitted to the experimental values of molar conductivity, Λ, to obtain molar conductivities at infinite dilution, Λo. The molar conductivities at infinite dilution for each acid were used to calculate degrees of dissociation and ionization constants in D2O versus H2O from 298 K to 571 K. Measured values of differences in pKaq in D2O vs H2O, ΔpKaq = [pKaq,D2O – pKaq,H2O], become relatively independent of temperature above 423 K, with values of: ΔpKaq 0.45 for acetic acid and ΔpKaq 0.35 for phosphoric acid. The Density Model was then fitted to the values of pKaq in H2O and D2O to represent their temperature dependence to a precision of ± 0.01 in ΔpKaq. Comparisons of the molar conductivities and ionic molar conductivities at infinite dilution for the strong electrolytes in H2O and D2O as a function of temperature have also been made, based on Walden’s rule correlations, (λ°•η)D2O / (λ°•η)H2O. Changes in values of (λ°•η)D2O / (λ°•η)H2O as a function of temperature are consistent with a change in the relative hydration behavior of ions, where the effective Stokes’ radii of the ions in D2O versus H2O changes at temperatures above ~ 450 K. Changes in values of (λ°•η)D2O / (λ°•η)H2O for D+/H+ and OD-/OH- suggest that proton hopping “Grotthuss” mechanisms become more efficient in D2O versus H2O with increasing temperature. / University Network of Excellence in Nuclear Engineering, Ontario Power Generation Ltd, Natural Science and Engineering Research Council of Canada

The interaction between metal nanoparticles and small molecules has been investigated by FTIR and UV-visible absorption spectroscopy. Electrospray deposition into an argon matrix was chosen as the initial method. An electrospray metal source was tested in development stage. Both the formation of a stable corona discharge as well as a stable Taylor cone were successfully completed. Problems arose when the entire system was tested. It was determined that the vacuum was insufficient for the length of the flight path. Focus then shifted to nanoparticles in more conventional environments. Sol-gel encapsulated nanoparticles were generated, in the form of both monoliths as well as thin film coatings on silicon wafers. The gels were exposed to 1atm of carbon monoxide in a gas cell. The method encountered problems due to spectral interference from the matrix. The next attempt consisted of solution stabilized nanoparticles. The solution was exposed to various amounts of both ammonium sulphate and diethylamine. There was again the problem of solvent interference, even when attempting to observe the system using Raman spectroscopy. Finally, surface stabilized nanoparticles were generated, using 3-mercaptopropyltrimethoxysilane to adhere the particles to glass slides. While the coating was successfully applied to the glass slides, as confirmed with Raman spectroscopy, it was not possible to get the nanoparticles to adhere. Future outlook for this project is briefly reviewed. / Thesis (Master, Chemistry) -- Queen's University, 2009-06-26 10:30:58.295

In clinical diagnosis and fermentation industries there is a need for a method that allows for the differentiation of yeast to the strain level (biotyping). The ideal biotyping method should be accurate, simple, rapid and cost-effective, and capable of testing a large number of yeast isolates. Matrix assisted laser desorption/ionization time of flight mass spectrometry has emerged as a powerful biotyping tool for the identification of bacteria and clinical yeast isolates, mainly Candida. It has been found that the MALDI-TOF MS signals from yeast are harder to obtain than from bacteria. It has been reported by several research studies that a cell lysis step is required to obtain a mass spectral signal for clinical Candida strains. To date an optimized sample preparation protocol has not been devised for the biotyping of S. cerevisiae strains. Studies on the identification of yeast using MALDI-TOF MS have focused primarily on clinical Candida yeast isolates but have included very few S. cerevisiae strains. Furthermore these yeast identification studies using MALDI-TOF MS have only achieved identification to the species and not strain level. A major limiting attribute of MALDI-TOF MS for the accurate identification of microbes, is its dependency on a comprehensive mass spectral database. Bruker Daltonics is a pioneer and leader in providing innovative life science tools based on mass spectrometry thus the Bruker Daltonics mass spectral database and state-of-the-art instruments and accompanying software were selected for this study. The Bruker Daltonics mass spectral database currently holds three thousand seven hundred and forty microorganisms of which only a mere seven are S. cerevisiae strains. Initially in this study, a number of parameters of a generic ethanol/formic acid protein extraction procedure as originally described by Bruker Daltoincs were considered in the development of a sample preparation protocol that yielded characteristic and highly reproducible MALDI-TOF mass spectra. The parameters considered included cell number, alcohol fixation, matrix solution and media. It was found that using the optimized sample preparation protocol unique and highly reproducible mass spectral profiles were obtained for all three S. cerevisiae strains. Multivariate analysis confirmed that the differences between all three S. cerevisiae strains were statistically significant. For quality assurance, the spectra of the three strains were sent for evaluation by Bruker Daltonics and were deemed suitable for the purpose of biotyping. The newly created ethanol/formic acid extraction procedure was used to generate an S. cerevisiae mass spectral database comprising of forty-five S. cerevisiae strains within a local context but also of global significance. The accuracy of the mass spectral database was assessed using blind coded S. cerevisiae strains obtained from the Agricultural Research Council Infruitec-Nietvoorbij (Institute for Deciduous Fruit, Vines and Wine), Stellenbosch, South Africa. It was found that S. cerevisiae identification to the species and more importantly strain level was achievable with relatively good accuracy. To determine the potential application of MALDI-TOF MS as an accurate method for S. cerevisiae strain identification in industry, blind coded S. cerevisiae strains were obtained from Natal Cane Products and subjected to MALDITOF MS analysis. It was found that four of the pure cultures submitted were correctly identified to the strain level and the three S. cerevisiae strains incorrectly identified may have been contaminants or the result of incorrect optimization conditions for the fermentation. Thus MALDITOF MS was shown to be an accurate identification tool, that may also be used to detect contaminants or incorrect environmental conditions which can result in substantial losses. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

Providing intense, contamination-free beams of rare isotopes to experiments is a challenging task. At isotope separator on-line facilities such as ISAC at TRIUMF, the choice of production target and ion source are key to the successful beam delivery. Due to their element-selectivity, high efficiency and versatility, resonant ionization laser ion sources (RILIS) gain increasingly in importance. The spectroscopic data available are typically incomplete in the region of excited- and autoionizing atomic states. In order to find the most efficient ionization scheme for a particular element, further spectroscopy is often required. The development of efficient laser resonant ionization schemes for yttrium and astatine is presented in this thesis. For yttrium, two ionization schemes with comparable relative intensities were found. Since for astatine, only two transitions were known, the focus was to provide data on atomic energy levels using resonance ionization spectroscopy. Altogether 41 previously unknown astatine energy levels were found.

The detection of sound sources with microphone arrays can be enhanced through processing individual microphone signals prior to the delay and sum operation. One method in particular, the Phase Transform (PHAT) has demonstrated improvement in sound source location images, especially in reverberant and noisy environments. Recent work proposed a modification to the PHAT transform that allows varying degrees of spectral whitening through a single parameter, andamp;acirc;, which has shown positive improvement in target detection in simulation results. This work focuses on experimental evaluation of the modified SRP-PHAT algorithm. Performance results are computed from actual experimental setup of an 8-element perimeter array with a receiver operating characteristic (ROC) analysis for detecting sound sources. The results verified simulation results of PHAT- andamp;acirc; in improving target detection probabilities. The ROC analysis demonstrated the relationships between various target types (narrowband and broadband), room reverberation levels (high and low) and noise levels (different SNR) with respect to optimal andamp;acirc;. Results from experiment strongly agree with those of simulations on the effect of PHAT in significantly improving detection performance for narrowband and broadband signals especially at low SNR and in the presence of high levels of reverberation.

No description available.

Providing intense, contamination-free beams of rare isotopes to experiments is a challenging task. At isotope separator on-line facilities such as ISAC at TRIUMF, the choice of production target and ion source are key to the successful beam delivery. Due to their element-selectivity, high efficiency and versatility, resonant ionization laser ion sources (RILIS) gain increasingly in importance. The spectroscopic data available are typically incomplete in the region of excited- and autoionizing atomic states. In order to find the most efficient ionization scheme for a particular element, further spectroscopy is often required. The development of efficient laser resonant ionization schemes for yttrium and astatine is presented in this thesis. For yttrium, two ionization schemes with comparable relative intensities were found. Since for astatine, only two transitions were known, the focus was to provide data on atomic energy levels using resonance ionization spectroscopy. Altogether 41 previously unknown astatine energy levels were found.

SuperB is a high luminosity e+e- collider experiment that is currently being designed to explore the flavour sector of particle physics. The detector at SuperB will contain a drift chamber, a gas filled device used to measure the momentum and identity of particles produced in the collisions. Particle identification in a drift chamber uses the measured amount of ionization deposited by the particle in the cells of the chamber, which provides a measurement of the particle speed. The ionization loss is traditionally measured by integrating the total charge released by the ionization after a gas amplification avalanche process. Since such a measurement has potentially large uncertainties associated with fluctuations in the gas amplification and other processes, it is possible that measuring the number of primary clusters of ionization caused by the particle could provide an improvement in the measurement of the ionization loss. The results of experiments performed at the University of Victoria and the TRIUMF laboratory M11 test beam using a SuperB drift chamber prototype to test the feasibility of counting clusters are presented here. The ability to separate muons and pions at the momenta explored in the TRIUMF testbeam was similar to the ability to separate pions and kaons at the higher momenta of SuperB. It was found that counting the clusters provides a significant improvement to particle identification when combined with the traditional measurement of the integrated charge. / Graduate

An experimental method (the two-dose-rate method) for the correction of general recombination losses in liquid ionization chambers has been developed and employed in experiments with different liquids and radiation qualities. The method is based on a disassociation of initial and general recombination, since an ionized liquid is simultaneously affected by both of these processes. The two-dose-rate method has been compared to an existing method for general recombination correction for liquid ionization chambers, and has been found to be the most robust method presently available. The soundness of modelling general recombination in liquids on existing theory for gases has been evaluated, and experiments indicate that the process of general recombination is similar in a gas and a liquid. It is thus reasonable to employ theory for gases in the two-dose-rate method to achieve experimental corrections for general recombination in liquids. There are uncertainties in the disassociation of initial and general recombination in the two-dose-rate method for low applied voltages, where initial recombination has been found to cause deviating results for different liquids and radiation qualities. Sensitivity to ambient electric fields has been identified in the microLion liquid ionization chamber (PTW, Germany). Experimental data may thus be perturbed if measurements are conducted in the presence of ambient electric fields, and the sensitivity has been found to increase with an increase in the applied voltage. This can prove to be experimentally limiting since general recombination may be too severe for accurate corrections if the applied voltage is low.

No description available.