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Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1936. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed June 9, 2010)

Technological advances are required to reduce the environmental impact of the Canadian oil sands. Oxy-direct contact steam generation (DCSG) is one such way to move toward this goal, by producing steam for oil sands operations with a higher efficiency, lower fresh water consumption, and lower CO₂ emissions than traditional once-through steam generators. For DCSG, untreated process water, which may contain a variety of inorganics, is injected directly into the combustor to produce steam. The inorganic material that may deposit in the combustor as a result of that process water was studied for two applications of DCSG in the Canadian oil sands: (1) steam assisted gravity drainage (SAGD), and (2) mining, in order to inform refractory material selection for the combustor. For SAGD, free water knockout tank discharge was used as the process water and resulting deposits in the combustor were predicted to be high in silica and sodium oxide, and enriched with sodium sulfate as the potential operating temperature of the combustor was lowered. At the lowest combustor temperature studied (1075 °C), a low viscosity molten salt phase rich in sodium sulfate was also expected to form. It is recommended that the operating temperature of the combustor be as low as possible while still remaining above the formation temperature of this potentially corrosive salt phase, thus in the range of 1200-1250 °C in the regions of the wall where solids are expected to impact it. A number of candidate refractory materials were assessed through corrosion models and corrosion tests. Aluminosilicate based refractory materials should be avoided due to their potential reaction with the sodium oxide in the slag. This can result in formation of low density solid phases such as nepheline, which can damage the refractory material through volume expansion. Of the three refractories tested, mullite zirconia yielded the worst corrosion resistance, with dissolution of the binder phase and full penetration by sodium oxide. Chromia corundum yielded the greatest resistance to penetration of the materials tested, though some dissolution of the chromia in the slag was still evident. Further investigation into high chrome refractory materials is recommended for this application. For mining applications, mature fine tailings water (MFT) combined with an oil sands processing water (OPW) was used as the process water for injection. Due to the high liquidus of the resulting inorganic deposits, co-injection of a fluxant is recommended to reduce the liquidus and viscosity of the resulting slag solution, thereby maximizing the combustor efficiency by reducing the required operating temperature. Dolomite was identified as the optimal fluxant, at a concentration of 20 wt % CaMgO₂ in the fluxed slag. This mixture was found to have a viscosity of just under 25 Pa·s at 1300 °C, making this a good operating point for the DCSG combustor, as the slag should flow freely and not cause plugging. The corrosion resistance of several candidate refractory materials was assessed through modelling and laboratory scale testing for both the fluxed and non-fluxed slag. Similar to the results for SAGD, of the refractories tested, chromia corundum offered the greatest resistance to penetration, while mullite zirconia was most deeply penetrated by sodium oxide. Again, a chromia-containing refractory is recommended for further investigation for use in the DCSG combustor. Other candidate refractories investigated in the models that warrant testing are chromia spinel and magnesium aluminate spinel. For future work, further corrosion tests at multiple durations are recommended, as well as characterization of refractory samples from CanmetENERGY’s DCSG pilot plant and quantification of the effects of slag exposure on the mechanical strength of the refractory materials.

Retroperitoneal liposarcoma is often asymptomatic but sometimes attention is drawn to the neoplasm due to clinical manifestations. These include fever, flu-like symptoms, nausea or vomiting due to pressure or hypoglycemia related to paraneoplastic disease. We present a rare case of a massive retroperitoneal liposarcoma presenting with refractory dry cough. The patient underwent resection of the mass with complete resolution of her cough. Histopathological examination of the mass demonstrated a well-differentiated tumor with myxomatous features. No evidence of metastatic disease to the lungs was observed. This case points to the need for a thorough and careful evaluation of unexplained cough.

Retroperitoneal liposarcoma is often asymptomatic but sometimes attention is drawn to the neoplasm due to clinical manifestations. These include fever, flu-like symptoms, nausea or vomiting due to pressure or hypoglycemia related to paraneoplastic disease. We present a rare case of a massive retroperitoneal liposarcoma presenting with refractory dry cough. The patient underwent resection of the mass with complete resolution of her cough. Histopathological examination of the mass demonstrated a well-differentiated tumor with myxomatous features. No evidence of metastatic disease to the lungs was observed. This case points to the need for a thorough and careful evaluation of unexplained cough.

M.S.

M.S.

Refractometry is a means to measure the refractive indices of liquids, gases, and dielectric solids, either isotropic or anisotropic, by observation of light refraction or reflection with a microscope, refractometer or other more specialized equipment. For anisotropic solids, refractometry by total reflection (RTR) is by far the simplest, most rapid, and precise method to determine the refractive indices, provided a polished surface of sufficient size exists. Its precision exceeds that for routine oil immersion techniques but compares less favorably to that for minimum deviation methods. However, minimum deviation requires large crystals and, moreover, specifically oriented prisms, one for each principal refractive index to be measured and, for triclinic crystals, one for each wavelength of measurement. The phenomenon of polarized light reflection from randomly oriented anisotropic materials has been modeled because, only after a complete understanding of these phenomena could the R TR method be automated. The mathematics and physics required for this stem from theories and equations presented in the literature of ellipsometry, polarized light, and physical optics. These were then modified, rewritten, and unified to suit the requirements of R TR. RTR, first used by Wollaston ( l 802a, l 802b ), was later perfected for the measurement of the refractive indices and orientation of biaxial minerals in thin section (Viola l 899a, l 899b, 1902; Comu 1901, 1902). RTR with the Abbe-Pulfrich refractometer yielded refractive indices to a precision of ±0.0002, or better. Later, Smith (1905a, 1905b) introduced a simpler refractometer, now known as the jeweler's refractometer, which had a precision of ±0.001 to ±0.002. This refractometer is still in use by gemologists. During this century familiarity with the early work has declined; thus several recent papers display a lack of knowledge of aspects of R TR which were already documented in the early 1900s. A new automated refractometer, designed by Bloss, has precision of ±0.0002 and will be able to measure the refractive indices and orientation of a biaxial mineral in a petrographic thin section. Even for triclinic crystals, a single polished surface arbitrarily oriented will suffice for measurement of all three principal refractive indices, whatever the wavelength supplied. The design and testing of this refractometer has taken approximately three years. Two prototypes have been built and tested. Results from the second prototype are presented. / Ph. D.

Ceria (CeO2), chromia (Cr2O3), yttria-stabilized zirconia (Y2O3-ZrO2), and sodium cerium oxide (Na2CeO3) were used as barrier coatings on Ufala, an alumina-based ceramic refractory, to determine if they were effective at increasing the life of the refractory in a high-temperature black liquor gasification environment. The ceria, chromia, and yttria-stabilized zirconia coatings were applied at atmospheric pressure using a coating applicator at the Institute of Paper Science and Technology at the Georgia Institute of Technology. The sodium cerium oxide coatings in addition to the three other coating types were applied under atmospheric pressure at C3 International Technologies in Alpharetta, GA. The coated refractory, as well as a set of uncoated refractory used for baseline analysis, were tested using molten synthetic smelt at 1000C for 36 hours. Uncoated refractory samples were also tested for 12, 72, 120, and 168 hours in order to make a kinetic reaction rate determination. The refractory were analyzed using gravimetric and dimensional analysis, X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy to determine the severity of the physical changes that occurred after exposure to molten smelt. The data gathered from these experiments were not able to conclude that barrier coatings are sufficient to impede corrosion of the Ufala refractory material in molten smelt.

Ni-based superalloys remain state-of-the-art materials for use in the high-temperature, corrosive environments experienced by turbine blades in gas turbine engines used for propulsion and energy generation. Increasing the operating temperatures of turbine engines can yield increased engine efficiencies. However, appreciably higher operational temperatures can exceed the capabilities of Ni-based superalloys. Consequently, interest exists to develop high-melting refractory complex concentrated alloys (RCCAs) with the potential to surpass the hightemperature property limitations of Ni-based alloys. RCCAs are multi-principal element alloys, often comprising 5 or more elements in equal or near equal amounts. Conventional solidificationbased processing methods (e.g., arc melting) of RCCAs tend to yield coarse-grained samples with a large degree of microsegregation, often requiring long subsequent homogenization annealing times. Additionally, the large differences in melting temperatures of component elements can further complicate solidification-based fabrication of RCCAs. <div>Herein, the feasibility of a new chemical synthesis, powder metallurgy route for generating fine-grained, homogenous RCCAs is demonstrated. This is achieved by first employing the Pechini method, which is a well-developed process for generating fine-grained, oxide powder mixtures. The fine oxide powder mixture is then reduced at a low temperature (600°C-770 ºC) to yield fine-grained metal alloy powder. Hot pressing of the metallic powder is then used to achieve dense, fine-grained metallic alloys. While this process is demonstrated for generating fine-grained, high-melting MoW and MoWCr alloys, this method can be readily extended to generate other finegrained RCCA compositions, including those unachievable by solidification-based processing methods.</div>