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Full-Text Articles in Engineering
Mechanically Activated Combustion Synthesis Of Molybdenum Borosilicides For Ultrahigh-Temperature Structural Applications, Alan Alberto Esparza Hernandez
Mechanically Activated Combustion Synthesis Of Molybdenum Borosilicides For Ultrahigh-Temperature Structural Applications, Alan Alberto Esparza Hernandez
Open Access Theses & Dissertations
The desire to improve the efficiency of power generation gas-turbines has led to a relentless quest for new, ultrahigh-temperature structural materials to replace the current nickel-based superalloys. These materials have reached the maximum allowable operating temperature determined by the melting temperature of these alloys, which is about 1150 °C. These materials could be replaced by molybdenum silicides and borosilicides based on Mo5SiB 2 (T2) phase due to their high melting point and mechanical properties. A major challenge, however, is to simultaneously achieve high oxidation resistance and acceptable mechanical properties at elevated temperatures. One novel approach to improve these properties is …
Investigation Of Ti-6al-4v Alloy Response To Atmospheric Re-Entry Exposure, Jessica Lynn Buckner
Investigation Of Ti-6al-4v Alloy Response To Atmospheric Re-Entry Exposure, Jessica Lynn Buckner
Open Access Theses & Dissertations
Ti-6Al-4V is a widely used aerospace alloy for its high strength-to-weight ratio and high operating temperature properties. Despite widespread use, titanium and its alloys have been shown to ignite in oxygen and nitrogen rich test streams. The reactivity of titanium is attributed to the high solubility for oxygen that increases with temperature, accelerating the oxidation rate and resulting in a combustion reaction. When introduced to the monatomic oxygen rich and high enthalpy re-entry environment, Ti-6Al-4V X-link components from the space shuttle Columbia exhibited accelerated oxidation and combustion behavior. Ti-6Al-4V metal plates tested in the simulated re-entry environment of an arc-jet …
Investigating The Influence Of Gold Nanoparticles On The Photocatalytic And Catalytic Reactivity Of Porous Tungsten Oxide Microparticles, Daniel P. Depuccio
Investigating The Influence Of Gold Nanoparticles On The Photocatalytic And Catalytic Reactivity Of Porous Tungsten Oxide Microparticles, Daniel P. Depuccio
Graduate College Dissertations and Theses
Tungsten oxide (WO3) is a semiconducting transition metal oxide with interesting electronic, structural, and chemical properties that have been exploited in applications including catalysis, gas sensing, electrochromic displays, and solar energy conversion. Nanocrystalline WO3 can absorb visible light to catalyze heterogeneous photooxidation reactions. Also, the acidity of the WO3 surface makes this oxide a good thermal catalyst in the dehydration of alcohols to various industrially relevant chemicals. This dissertation explores the photocatalytic and thermal catalytic reactivity of nanocrystalline porous WO3 microparticles. Furthermore, investigations into the changes in WO3 reactivity are carried out after modifying the porous WO3 particles with gold …