Theses and Dissertations at Montana State University (MSU)
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Item Bio-trapping ureolytic bacteria on sand to improve the efficiency of biocementation(Montana State University - Bozeman, College of Engineering, 2023) Ugur, Gizem Elif; Chairperson, Graduate Committee: Chelsea M. Heveran; Adrienne J. Phillips (co-chair); This is a manuscript style paper that includes co-authored chapters.Microbially induced calcium carbonate precipitation (MICP) has emerged as a novel biocementation technique for its potential solution to sustainable construction. Although current MICP approaches have made significant progress, achieving spatial control over biomineralization is challenging due to its complexity, which is affected by many factors, such as microorganisms, reaction kinetics, and environmental factors. Spatially controlling biomineralization for building or targeted repair of materials can significantly improve efficiency and sustainability while achieving desired outcomes. The purpose of this thesis was to assess whether biomineralization can be enhanced through surface pre-treatment of sand using amino silanes, such as 3-aminopropyl-methyl-diethoxysilane (APMDES), which is one form of spatial control of biomineralization through prescribing the location of the microbes. Moreover, a preliminary study was conducted to assess whether biomineralized sand, with and without the APMDES treatment, can be recycled and reused for biomineralization of subsequent generations. The impact of APMDES treatment on bacterial adhesion on sand, growth, and urease activity was analyzed. Biocementation efficiency was evaluated by comparing compressive strength and calcium gain of APMDES-treated sand with untreated sand. APMDES treatment promotes abundant and immediate trapping of bacteria on sand surfaces through increased electrostatic interaction that attracts negatively charged walls of bacteria to positively charged amine groups. While APMDES treatment compromises microbial viability, it preserves the urease enzyme for catalyzing urea hydrolysis. APMDES-treated sand achieved comparable strength with fewer bacterial injections compared to untreated sand. APMDES-treated sand biocemented using three injections of bacteria and cementation media gained the same strength as seven injections. Biomineral gain of APMDES-treated sand was similar compared to untreated sand, which shows calcium accrual in the structure may be influenced by additional factors, such as the distribution of calcite, differences in the calcite precipitation patterns, and morphology. Overall, incorporating APMDES treatment can potentially improve the efficiency and sustainability of MICP by spatially controlling biomineralization.Item Stabilization of metallic catalyst microstructures against high-temperature thermal coarsening(Montana State University - Bozeman, College of Engineering, 2016) Driscoll, David Robert; Chairperson, Graduate Committee: Stephen W. Sofie; Clay D. Hunt, Julie E. Muretta and Stephen W. Sofie were co-authors of the article, 'Thermally stabilized nickel electro-catalyst introduced by infiltration for high temprature electrochemical energy conversion' in the journal 'Transactions of the Electrochemical Society' which is contained within this thesis.; Cameron H. Law and Stephen W. Sofie were co-authors of the article, 'Design and synthesis of metallic nanoparticle-ceramic support interfaces for enhancing thermal stability' in the journal 'Ceramic transactions' which is contained within this thesis.; Stephen W. Sofie was a co-author of the article, 'Stabilization of nano-scale metallic microstructure against thermal coarsening' in the journal 'Ceramic transactions' which is contained within this thesis.; Melissa D. McIntyre, Martha M. Welander, Stephen W. Sofie and Robert A. Walker were co-authors of the article, 'Enhancement of high temperature metallic catalysts : aluminum titanate in the nickel-zirconia system' in the journal 'Applied catalysis A: general' which is contained within this thesis.; Thesis contains two articles of which David Robert Driscoll is not the main author.; Melissa D. McIntyre, Martha M. Welander, Daniel E. Perea, Robert A. Walker and Stephen W. Sofie were co-authors of the article, 'Aluminum oxide processed as a beneficial additive in SOFC anodes' submitted to the journal 'Journal of the electrochemical society' which is contained within this thesis.; Clay D. Hunt, Daniel E. Perea, and Stephen W. Sofie were co-authors of the article, 'Diffusion caging : thermodynamic arrest of Ostwald ripening' submitted to the journal 'Advanced Materials' which is contained within this thesis.The size and shape of metal particulate at high temperature is dictated by surface energy. In systems containing very small metal particles, smaller particles shrink and disappear as they grow into larger particles in a process referred to as coarsening. Coarsening causes irreversible degradation in a number of important systems including automotive catalytic converters and solid oxide fuel cells (SOFC) through a loss of catalyst (metal) surface area. This phenomenon is exemplified by nickel metal catalyst that is supported on ytrria-stabilized zirconia (YSZ) which represents a materials system critical to the function of SOFCs. It has been demonstrated that additions of aluminum titanate (ALT) to the Ni-YSZ system with subsequent thermal treatment can act to stabilize the geometry of Ni on YSZ. In demonstration SOFCs, ALT has increased the time required for the first 10% of degradation by a factor of 115. This work has sought to elucidate the mechanisms by which ALT imparts increased stability. The work contained here demonstrates that ALT easily decomposes to Al 2O 3 and TiO 2. During thermal treatment, the alumina reacts with NiO to form nickel aluminate and the titania interacts with the YSZ where it can form Zr 5Ti 7O 24 -- a mixed ion electron conducting phase. In this way, the Al and Ti components of ALT have been determined to act independently where alumina appears to be dominant in microstructural stabilization. During cell operation, the nickel aluminate decomposes to nickel metal decorated with alumina nano-particulate. This geometry forms the basis of 'diffusion caging' as a stabilization mechanism which is the subject of Chapter 8. The role of titania appears to be less important except when processing occurs in a way that facilitates formation of the MIEC phase. However, Ni-YSZ cermets have also shown a strength enhancement when doped with ALT. This strength enhancement is likely due to the influence of titania (Chapter 7). Future work has the potential to extend concepts discussed here to a number of high temperature catalytic systems.