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Soot and other products of incomplete combustion play an important role in the chemistry of the atmosphere. As particles are exposed to trace gases, such as ozone, their chemistry and physical properties can be altered leading to changes in their optical properties, as well as their cloud condensation nuclei and ice nucleation abilities. These alterations can lead to changes in the global radiative budget and cloud microphysical processes, which in turn affect the climate. In this study, the chemical and physical changes associated with the oxidation of pyrene, anthracene, and carbon (lampblack) by ozone were investigated. Fourier Transform Infrared Spectroscopy was used to identify oxidation products and track reaction progress for these representative aerosols. A C=O band attributed to a carboxylic acid formation was observed for all three substances, at each level of exposure to ozone - 20 ppm, 40 ppm, and 80 ppm. Second order reaction rate constants ranged from 9.58 x 10-16 cm2 molecules-1 s-1 to 7.71 x 10-13 cm2 molecules-1 s-1. Measurements of water uptake, ice nucleation efficiency, and optical properties were obtained to determine whether any physical changes associated with the oxidation process occurred. Optical measurements show an increase in the ultra-violet absorption of anthracene, but not for pyrene, while an increase in the visible absorption for pyrene was observed, but not for anthracene. Oxidized soot froze at a warmer temperature (-22.8 degrees C) then fresh soot (-25.6 degrees C), showing an increase in ice nucleation efficiency. Our data indicates that oxidation by ozone does alter the chemistry and physical properties of the substances study, leading to possible changes in how they interact with atmospheric processes.

Two flow reactor studies, using an electrically heated laminar flow reactor over Vanadia based (V2O5-WO3/TiO2) honeycomb catalyst, were performed at 1 atm pressure and various temperatures. The experiments were conducted using simulated exhaust gas compositions for different exhaust gases. A quartz tube was used in order to establish inert conditions inside the reactor. The experiments utilized a Fourier transform infrared (FTIR) spectrometer in order to perform both qualitative and quantitative analysis of the reaction products. Urea-water solution decomposition was investigated over V2O5-WO3/TiO2 catalyst over the entire SCR temperature range using the temperature controlled flow reactor. The solution was preheated and then injected into pure nitrogen (N2) stream. The decomposition experiments were conducted with a number of oxygen (O2) compositions (0, 1, 10, and 15%) over the temperature range of 227oC to 477oC. The study showed ammonia (NH3), carbon-dioxide (CO2) and nitric oxide (NO) as the major products of decomposition along with other products such as nitrous oxide (N2O) and nitrogen dioxide (NO2). The selective catalytic reduction (SCR) of nitric oxide (NO) with urea-water solution over V2O5-WO3/TiO2 catalyst using a laboratory laminar-flow reactor was investigated. Urea-water solution was injected at a temperature higher than the vaporization temperature of water and the flow reactor temperature was varied from 127oC to 477oC. A FTIR spectrometer was used to determine the concentrations of the product species. The major products of SCR reduction were NH3, NO and CO2 along with the presence of other minor products NO2 and N2O. NO removal of up to 87% was observed. The aim of the urea-water decomposition experiments was to study the decomposition process as close to the SCR configuration as possible. The aim of the SCR experiments was to delineate the effect of various parameters including reaction temperature and O2 concentration on the reduction process. The SCR investigation showed that changing parameter values significantly affected the NO removal, the residual NH3 concentration, the temperature of the maximum NO reduction, and the temperature of complete NH3 conversion. In the presence of O2, the reaction temperature for maximum NO reduction was 377?C for ratio of 1.0.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 132-137). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 134-139). Also available on the Internet.

Thesis (M.Sc.-Res.)--University of Wollongong, 2009. / Typescript. Includes bibliographical references: leaf 91-95.

Thesis (M.S.)--Mechanical Engineering, Georgia Institute of Technology, 2004. / Fedorov, Andrei, Committee Member ; Mahan, J. Robert, Committee Member ; Zhang, Zhuomin, Committee Chair. Includes bibliographical references (leaves 80-82).

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 134-139). Also available on the Internet.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: clean extinguishing agent; c₆f-ketone; novec 1230; thermal decomposition products; halon alternative. Includes bibliographical references.

This thesis details research undertaken in the investigation of the open-shell open-shell Van der Waals complexes between nitric oxide (NO) and oxygen (O₂) and between nitrogen dioxide (NO₂ ) and oxygen (O</sub>2</sub> ). The Fourier transform microwave spectroscopy technique was used during the experimental work. Spectra were recorded for a mixture of NO and O₂ over the frequency range 7.0 to 18.2 GHz. Detailed ab initio calculations have been performed on the potential energy surface of both NO-O₂ and NO₂-O₂ using Multi-reference Rayleigh Schrodinger Second Order Perturbation Theory. These calculations were performed for the four distinct states of NO-O₂, ²A", ⁴A", ²A' and ⁴A', and for the two distinct states of NO,sub>2</sub>-O₂, ²A and ⁴A. Predicted rotational spectra have been generated by modelling the systems with a rigid-rotor Hamiltonians. The effective Hamiltonians included the rotational Hamiltonian, ℋ_rot, fine structure terms and hyperfine structure terms. It was not possible, for rationalizable reasons, to fit the predicted spectra for NO-O₂ to the experimental observations. Experimental details, calculation methods and rotational theory are discussed in the main body of the thesis. Predicted spectra, relevant calculations and other data is presented in the appendices.