Scholarship & Research
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Item Development of surface preparation procedure recommendations for wind turbine blade field repairs(Montana State University - Bozeman, College of Engineering, 2022) Lusty, Ariel Francis; Chairperson, Graduate Committee: Douglas S. CairnsWind turbine blades necessitate reliable field repairs. However, the effects of current wind turbine field repair surface preparation techniques were not well- documented. Poorly informed surface preparation procedures lead to poor quality repairs, so surface preparation procedure recommendations for wind turbine blade field repairs were developed. The effectiveness of current surface preparation techniques, the effects of contaminants, and alternative techniques were evaluated. Current surface preparation techniques involve using solvent wiping to remove contamination. Results indicated that solvent wiping does not significantly affect bond strengths, but solvents can gel resin surfaces. Measuring the changes in bond strengths due to contamination from composite dust and hydraulic oil with time indicated that contamination diffusion effects along bond lines were negligible, but that composite dust and hydraulic oil diminished bond strengths. Contaminants should thus be removed from bond line surfaces prior to repairs. The goal of considering alternative techniques was to increase and equalize the surface energy of repair surfaces using plasma or sizing. There were significant drops in contact angles on composite surfaces treated with plasma, so plasma treatments should continue to be considered for composite surface preparation methods. To examine sizing effects, sizing was applied to scarfed surfaces and specimens were tested in tension. Applying sizing to tapered surfaces prior to scarf repairs did not affect scarf tension ultimate stress values, failure modes, or failure surface elemental composition. In addition, there was a stiffness reduction in the scarfed specimens compared to unscarfed specimens, indicating that the scarf tension repair did not fully restore the composite plate's original properties. Scarf tension experiments were simulated using finite element analysis and results had good agreement between the experiments and the model. The surface preparation recommendation is to test whichever surface preparation methods and adhesive-substrate combinations are used for a repair prior to implementation in the field. Implementing testing of surface preparation methods with adhesive-substrate combinations into surface preparation procedures will decrease lifetime costs and increase energy production for wind turbines, which will ultimately reduce reliance on fossil fuels for societal energy needs.Item Characterization of manganese sulfide inclusion surfaces in 1018 carbon steels and interfacial studies of graphene coated copper surfaces(Montana State University - Bozeman, College of Letters & Science, 2021) Rieders, Nathaniel Frederic; Co-chairs, Graduate Committee: Recep Avci and Yves U. IdzerdaManganese sulfide inclusions are known to be sites of localized corrosion in steels, however little is know concerning the physical and chemical properties of inclusion surfaces. Some inclusions have been observed to be more corrosively active than others. In an effort to distinguish between active and inactive inclusions, this work utilizes surface sensitive electron spectroscopies and microscopies to characterize manganese sulfide inclusion interfaces in 1018 carbon steels. A method was developed to measure variations in surface potential with a high degree of spatial resolution using an Auger microscope. It was found that manganese sulfide inclusion surfaces are heterogeneous and possess discrete manganese oxide and copper sulfide phases. Valence band Auger spectroscopy was used to distinguish between various Mn and Fe chemical species. Surface potential measurements indicate that inclusions are more noble than the surrounding steel surface. TEM analysis indicates a high defect content at the inclusion/steel interface. It is hypothesized that active and inactive inclusions can be distinguished via the availability of sulfur. Graphene on copper surfaces were characterized for use as a protective coating against corrosion using surface sensitive spectroscopies. A feature in the copper Auger transition was found to be unique to graphene, and used to identify its presence and degree of substrate coupling. Localized oxidation of the copper substrate was observed to correlate with low surface potential regions, believed to be intercalated oxygen, which enhances the reactivity of the graphene overlayer. Intercalated Cl was observed to inhibit substrate oxidation, and reduce the reactivity of the graphene overlayer. The intercalation of water was observed to occur at room temperature, and molecularly adsorb to the copper surface at temperatures up to 200 C, indicating that graphene inhibits dissociation of water. Distribution of intercalated water was observed using Auger spectroscopy. It is suggested that doping of graphene is an effective strategy for use as an anticorrosive coating on heterogeneous surfaces.Item Reactive-atom scattering dynamics and liquid-vacuum interfacial structure(Montana State University - Bozeman, College of Letters & Science, 2019) Smoll, Eric James, Jr.; Chairperson, Graduate Committee: Timothy Minton; Maria Tesa-Serrate, Timothy K. Minton and Kenneth G. McKendrick were also authors of the article, 'Review of atomic and molecular collisions at liquid surfaces' in the journal 'Annual review of physical chemistry' which is contained within this dissertation.; Simon M. Purcell, Lucia D'Andrea, John M. Slattery, Duncan W. Bruce, Matthew L. Costen, Kenneth G. McKendrick and Timothy K. Minton were co-authors of the article, 'Probing conformational heterogeneity at the ionic liquid-vacuum interface by reactive atom scattering' in the journal 'The Journal of Physical Chemistry Letters' which is contained within this dissertation.; Timothy K. Minton was an author of the article, 'Scattering-angle randomization in nonthermal gas-liquid collisions' submitted to the journal 'Journal of physical chemistry C' which is contained within this dissertation.; John M. Slattery, Timothy K. Minton were also authors of the article, 'Probing a ruthenium coordination complex at the ionic liquid-vacuum interface with reactive atom scattering, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry' submitted to the journal 'Journal of physical chemistry C' which is contained within this dissertation.Experiments to characterize reactive and nonreactive gas-liquid scattering dynamics were carried out with the use of a crossed molecular beams apparatus configured for beam-surface scattering. In each experiment, the identity of the gas and liquid was strategically selected to reveal fundamental insights on the relationship between scattering observables and liquid-vacuum interfacial structure. This work is crucially important for the experimental advancement of liquid surface science and has the potential to impact our understanding of the chemical role of gas-liquid interfaces in the environment. An extensive literature review suggests that the inherent chemical specificity of reactive scattering is a promising probe of composition at the liquid-vacuum interface. We expand on what has been demonstrated in the literature by exploring F-atom scattering from the liquid-vacuum interface of deuterium labeled variants of the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 4 mim][Tf 2 N]). The experimental data and new molecular dynamics simulations provide evidence for the extreme surface specificity of reactive scattering and help quantify the relative populations of [C 4mim] + conformations at the liquid-vacuum interface. Also, at a fixed incident angle, the site-specific IS flux angular distributions from [C 4mim] + were discovered to be related by the addition or subtraction of a line-shape proportional to a cos(θf) function. To investigate this phenomenon, a separate study of noble gas scattering from the liquid-vacuum interface of other low vapor pressure liquids was carried out. Our results support the generality of the relative cos(θf) character trend and demonstrate that the relative cos(θf) character between total flux angular distributions from squalane and a perfluoropolyether is independent of gas identity and incident angle suggesting that this metric is an intrinsic property of the liquid pair. The existing evidence suggests that the relative cos(θf) character between flux angular distributions is a result of angle-randomization from multiple collision scattering trajectories induced by atomic-scale corrugation at the liquid-vacuum interface. A study on the liquid-vacuum interface structure of a solution of [RuCl 2(p-cymene)P(C 8H 17) 3] in perdeuterated 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (d 11-[C 2mim][Tf 2N]) is also discussed. The experimental data suggest that [RuCl(p-cymene)P(C 8H 17) 3] + is enriched at the liquid-vacuum interface at the expense of d 11-[C 2mim] + and the hydrocarbon chains of the Ru-complex protrude into the vacuum.Item Application of photoelectron holographic imaging to the study of Si(100) interfacial structures(Montana State University - Bozeman, College of Letters & Science, 1995) Yu, Mickey HongItem Local response theory of surface plasmons in the space-charge layer of GaAs (110)(Montana State University - Bozeman, College of Letters & Science, 1989) Xu, BingruoItem Microscopic study of electronic screening at simple metal surfaces(Montana State University - Bozeman, College of Letters & Science, 1991) Gaspar, Jorge AlbertoItem Incipient oxidation of A1(111) studied using optical second harmonic generation(Montana State University - Bozeman, College of Letters & Science, 1990) Wan, KejiaItem Oxidation of N:Al(110)(Montana State University - Bozeman, College of Letters & Science, 1990) Brown, Wade William