Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"Oxygen environments"”.
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Laser-Induced Particle Impact Testing in High-Pressure Oxygen Environments
… source of metal fires in the high-pressure oxygen environments found in the turbines of oxygen-rich turbopumps. Understanding of particle impact ignition has been hindered by experimental challenges in reproducing this phenomenon under controlled laboratory conditions. This study addresses …
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Fatigue behavior of Hastelloy-X at elevated temperatures in air, vacuum and oxygen environments.
Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.
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Design of a Pressure Vessel to Characterize Frictional Ignition of Metals in High-Pressure Oxygen Environments
The components of rocket engines are exposed to environments that are oxygen-rich, reach high-pressures, and cause the abrasion of rotating parts. Studies have shown that these conditions cause nearly all metals to develop an oxide tribolayer, which initially lubricates the rubbing surface, but …
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A Burn Ratio That Predicts the Relative Extent of Combustion in Metallic Materials.
… of the severity of combustion of metals in oxygen environments. Fires have occurred in oxygen compressors, pipelines, valves and storage tanks. A thermodynamic burn ratio is proposed that predicts the severity of combustion of metals in oxygen environments and is favorably compared with …
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Behavior and habitat selection of largemouth bass in response to dynamic environmental variables with a focus on dissolved oxygen
… investigates the effects that low dissolved oxygen concentrations and other dynamic environmental variables have on behaviors and distributions of largemouth bass, Micropterus salmoides a popular sportfish. To better understand how largemouth bass respond to low oxygen concentrations, I …
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Electrochemical Investigation of Thin Nickel, Copper and Silver Films Interfaced with Yttria-Stabilized Zirconia
… their response to polarization in dilute oxygen environments at 350 °C and assess their viability for electrochemical promotion of catalysis (EPOC). Polycrystalline YSZ (8 mol % Y2O3-ZrO2) pellets were synthesized in the lab and films deposited onto them using evaporative physical vapor …
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Quantitative assessment of the frictional ignition resistance of metals in high-pressure oxygen
… to frictional ignition in high-pressure oxygen environments. A previous ignition-resistance metric proposed by NASA WSTF varies strongly and unpredictably with test conditions, thus limiting its usefulness. The material index developed here incorporates key material properties that …
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Boron Particle Ignition and Combustion in a Shock Tube Using Time -Resolved Spectroscopy
… with XF/XO2 . Spectroscopic data taken in pure oxygen environments show residual BO2 emission after particle combustion, while that taken in fluorine-containing environments show little or no emission from BO2, consistent with predictions from theoretical modeling efforts. When boron particles …
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Ecology and adaptation of denitrifiers across genomes and environments
… to many marine, terrestrial, and aquatic environments. Microbes primarily mediate the many steps of the nitrogen cycle, including losses from anaerobic ammonia oxidation (anammox) and denitrification. The stepwise reduction of nitrate to nitrite, nitric oxide, nitrous oxide, and N2 gas, …
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Lipid Biomarkers for Marine Fungi
… for fungi have been used in terrestrial environments, such as soils, for many years, seldom few have investigated whether these are applicable for fungi in marine environments. <br/>This thesis set out to explore the composition of lipids across a range of marine<br/>derived fungi and …
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Behaviour of massive reinforced concrete sections in seawater
… (Phase I), corrosion propagation in low oxygen environments (Phase II), corrosion in statically and dynamically cracked sections (Phase III) and structural response of heavily corroded individual and lapped bar sections (Phase IV).<br/><br/>Phase I work shows a marked difference between …
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Pyrochlore spin ice Dy2Ti2O7: Investigating a platform for magnetic monopolar quasiparticles
… of monopole quasiparticles: competing effects of oxygen vacancy defect sites in bulk crystal, and effects of strains and surfaces in real spin ice systems. Investigation of these issues began with collaborating on the growth of Dy2Ti2O7 crystals in a range of oxygen environments, and of Dy2Ti2O7 …
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Integration of real time oxygen measurements with a 3D perfused tissue culture system
… with blood, which delivers nutrients, oxygen, and macromolecular regulatory molecules. In vitro culture models that incorporate local micro-perfusion in a format that allows accesses to cells and their microenvironment are desirable to a broad research community. This thesis describes a …
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From the atmosphere to the abyss: tracing organic carbon deposition, cadmium isotopes, and iron cycling using marine
… less than 4 % of the OC is buried in low-oxygen environments. However, in order to understand how the efficiency of the biological pump may have changed over time, it is necessary to use proxies. In Chapter 3, I examine cadmium isotopes as a potential paleonutrient proxy. I suggest that in …
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The Search for Novel Anthelmintic Targets: Characterizing Alternative Metabolic Pathways in Caenorhabditis elegans
… Helminths survive long periods of low to no oxygen in their hosts, but their anaerobic metabolism has yet to be fully characterized. The goal of this project has been to characterize the anaerobic metabolism of C. elegans, a roundworm closely related to a large class of parasitic worms, by …
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Isotopic constraints on sources and cycling of riverine dissolved inorganic carbon in the Amazon Basin
… lithologies, some small streams, and low-oxygen environments. A small, contemporary OC fraction dominates respiration; C4 vegetation exerts a disproportionate influence on lowland fluvial respiration. CO2 is typically more supersaturated and depleted in delta13C at high water. In the …
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Pulse Sharpening Effects of Thin Film Ferroelectric Transmission Lines
… 330 nm thick were grown by this method. Oxygen vacancies in the as grown BTO films were filled by annealing in low pressure oxygen environments. X-ray diffraction measurements were used to determine an O2 pressure for oxidation that was slightly less than the pressure at which NiO forms …
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From the atmosphere to the abyss: Tracing organic carbon deposition, cadmium isotopes, and iron cycling using marine sediments
… less than 4 % of the OC is buried in low-oxygen environments. However, in order to understand how the efficiency of the biological pump may have changed over time, it is necessary to use proxies. In Chapter 3, I examine cadmium isotopes as a potential paleonutrient proxy. I suggest that in …
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Measurement and characterization of low volatility organic compounds in the atmosphere
… organic compounds can also occur in low oxygen systems, such as in planetary atmospheres or in the process of soot formation. Ultraviolet light or heat can form radical hydrocarbon species, which, in low oxygen environments, will react with other hydrocarbon or radical species, undergoing …
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Reactions of aluminum with halogen containing oxides
… This study examines the effect of atmospheric oxygen concentration (4 or 93% oxygen) on energy propagation of nanometric aluminum with copper oxide (Al+CuO), iron oxide (Al+Fe2O3), calcium iodate (Al+Ca(IO3)2), and iodine pentoxide (I2O5). In all cases energy propagation was examined in terms …
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