Scholarship & Research
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/1
Browse
4 results
Search Results
Item Gas-surface interactions with sp 2 carbon in extreme environments(Montana State University - Bozeman, College of Letters & Science, 2018) Murray, Vanessa Jean; Chairperson, Graduate Committee: Timothy Minton; Brooks C. Marshall, Philip J. Woodburn and Timothy K. Minton were co-authors of the article, 'Inelastic and reactive scattering dynamics of hyperthermal O and O 2 on hot vitreous carbon surfaces' in the journal 'Journal of physical chemistry C' which is contained within this thesis.; Eric J. Smoll Jr. and Timothy K Minton were co-authors of the article, 'Dynamics of graphite oxidation at high temperature' in the journal 'Journal of physical chemistry C' which is contained within this thesis.; Marcin D. Pilinski, Eric J. Smoll, Jr., Min Qian, Timothy K. Minton, Stojan M. Madzunkov and Murray R. Darrach were co-authors of the article, 'Gas-surface scattering dynamics applied to concentration of gases for mass spectrometry in tenuous atmospheres' in the journal 'Journal of physical chemistry C' which is contained within this thesis.; Neil A. Mehta is an author and Chenbiao Xu, Deborah A. Levin and Timothy K. Minton were co-authors of the article, 'Scattering dynamics of N 2 from highly oriented pyrolytic graphite' in the journal 'Journal of physical chemistry C' which is contained within this thesis.; Chenbiao Xu, Savio Poovatthingal and Timothy K. Minton were co-authors of the article, 'Scattering dynamics of nitromethane and methyl formate on HOPG' submitted to the journal 'Journal of physical chemistry C' which is contained within this thesis.Molecular beam scattering experiments can determine the relative importance of reactive and non-reactive processes that occur when a surface is bombarded with high energy atoms and molecules. The mechanisms by which these processes proceed are inferred by analyzing the angle-resolved flux and energy distributions of the scattered products. The studies presented in this thesis have been conducted with a crossed molecular beams machine reconfigured for surface scattering. Two molecular beam sources were used. One uses a laser detonation process to produce high translational energy O atoms in the ground electronic state, and the other uses a supersonic expansion to produce continuous beams of N 2, nitromethane, or methyl formate. In the first two studies presented in this thesis, the oxidation of dynamics vitreous carbon and highly oriented pyrolytic graphite (HOPG) held at surface temperatures in the range of 800 - 2300 K by O atoms with a translational energy of ~ 500 kJ mol -1 are presented. These two studies revealed that the reactivity is suppressed at high temperature because O atoms desorb from the surface before they react to form CO and CO 2. Even though the translational energy of the O atoms was high, the surface reactions proceeded primarily through reactions that occurred in thermal equilibrium with the surface. The third study focuses on the scattering dynamics of O, O 2, and Ar with the surfaces of a gold thin-film, SiO 2, and HOPG. The results of the experiments were used to evaluate the efficacy of a proposed gas concentrator. The strong forward scattering on the HOPG surface made it the most suitable surface for the gas concentrator. The fourth study examines the non-reactive scattering dynamics of N 2 with HOPG. At high surface temperature, the residence time of N 2 is too short for the molecule to fully accommodate to the surface. Thus, even if the molecule suffers multiple collisions with the surface, it will scatter into the vacuum before it can come into thermal equilibrium with the surface. The results have been used in conjunction with theoretical calculations by a collaborator to investigate the relationship between the potential energy surface and the scattering dynamics. In order determine the usefulness of an HOPG concentrator with complex molecules, the scattering dynamics of methyl formate and nitromethane on HOPG were studied. These molecules do not shatter upon impact with the surface and they both scatter strongly in the forward direction through direct and indirect mechanisms, suggesting that the proposed HOPG concentrator should perform as desired. In all studies described in this thesis, the fundamental gas-surface scattering dynamics were elucidated from molecular beam experiments, and these fundamental results have direct links to modeling the performance of hypersonic vehicles and designing a gas concentrator for mass spectrometry in tenuous atmospheres.Item Weathering Montana : the social meanings of extreme environments in the Big Sky(Montana State University - Bozeman, College of Letters & Science, 2002) Conradt, Kevin; Chairperson, Graduate Committee: Mary MurphyHistorians have largely ignored the influence of weather and climate on people. In Montana, this has certainly been the case. In a state where meteorological stability is ephemeral, society is consistently challenged by the extreme nature of Montana’s environment. In my thesis I argue that the term weather, which is a social construction, is flawed for assessing Montana’s meteorological instability because it relies on a methodology that sees temperature and precipitation in average or normal conditions. I also argue that the extreme nature of Montana’s environment has helped to shape the societal infrastructure of the state, which has in turn strengthened the Treasure State’s historical narrative. This nascent methodology requires a comprehensive understanding of meteorology from a state, regional, and global perspective. The combination of latitude, atmospheric circulation, land-water distribution, and topography act in concert to create the variability associated with Montana’s natural environment. From a societal perspective I have relied on a combination of primary and secondary source information to interpret the perceptions of people and their relationship to Montana’s natural environment. The human journey in Montana has historically been influenced by the severe nature of the state’s weather and climate. From Native Americans to Euro-Americans, evidence of societal development in Montana, especially in agrarian enterprises, indicates that the construction of place has been largely influenced by the meteorological variability of Montana’s natural environment. As long as Montana’s natural environment continues to be influenced by meteorological instability, people will continue to challenge themselves against an environment of extremes. My hope is that future scholars interpreting the bond between people and weather will help to strengthen the methodology linking human beings with their nature environment.Item Proteomic analyses of Sulfolobus solfataricus : an extremophilic archaeon(Montana State University - Bozeman, College of Letters & Science, 2003) Barry, Richard CorneliusItem The search for Archaeal viruses in high temperature acidic environments and characterization of Sulfolobus turreted icosahedral virus (STIV)(Montana State University - Bozeman, College of Letters & Science, 2006) Rice, George Ernest; Chairperson, Graduate Committee: Mark YoungViruses of extreme thermophiles are of great interest because they can serve as model systems for understanding biochemical molecular nuances required for life at high temperatures. This two part body of work first reports the discovery and isolation of viruses and virus-like particles from extreme thermal acidic environments (70-92°C, pH 1.0-4.5) in Yellowstone National Park (YNP), and secondly details the characterization of one of these viruses that possesses a capsid structural motif that is found in at least two other families of viruses inhabiting the other two domains of life (Bacteria and Eukarya). This is of particular interest because it is the first example of a predicted but previously undocumented structural relationship between any entities (living or non) that span all three domains of life. The implications of this reported connection lend credence to the theory that there was a common viral ancestor, or ancestors, that predate the division of life into the three separate currently accepted domains.