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Carbothermal synthesis of titanium oxycarbideDewan, Mohammad Ashikur Rahman, Materials Science & Engineering, Faculty of Science, UNSW January 2009 (has links)
The aim of the project was to establish the rate and mechanisms of solid stage reduction of titania and ilmenite ores. The project examined carbothermal reduction of titania and various types of ilmenite ores in argon, helium, hydrogen, and their mixtures. Effect of CO in the gas atmosphere on reduction behavior of titania and primary ilmenite ore was also studied. Isothermal and non-isothermal reduction experiments were conducted in a fixed bed reactor in the high temperature furnace in the temperature range up to 1500oC. The off-gas composition in the reduction process was monitored by a CO/CO2/CH4 infrared analyser. The extent of reduction was calculated using data on gas composition and LECO oxygen analysis. Phase composition and morphology of reduced samples were studied using XRD, SEM and optical microscopy. The major findings of this project are as follows: The reduction of titania to titanium oxycarbide occurred in the following sequence: TiO2 → Ti5O9 → Ti4O7 → Ti3O5 → Ti2O3 → (TiO-TiC) solid solution. Carbothermal reduction of ilmenite concentrates proceeded in two main stages. In the first stage pseudorutile and ilmenite were reduced to metallic iron and titania. Second stage involved the reduction of titania to titanium oxycarbide. Rate and degree of reduction of titania and ilmenite concentrates increased with increasing temperature. Reduction rate of titania and ilmenite concentrates was faster in hydrogen than in helium and argon. The difference in the reduction behavior in helium and argon was insignificant; reduction rate of ilmenite was slightly faster in helium than in argon. High rate of reduction of titania and ilmenite in hydrogen was attributed to formation of methane which facilitated mass transfer of carbon from graphite to oxide. Hydrogen was also directly involved in reduction of titania and ilmenite concentrates; hydrogen reduced pseudorutile to iron and titania. Titania was further reduced to titanium oxycarbide by carbon through methane. Increased gas flow rate slightly improved the reduction rate in hydrogen and suppressed the reduction in inert gases. Addition of CO to hydrogen and inert gases above 3 vol% suppressed the reduction process.
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Carbothermal synthesis of titanium oxycarbideDewan, Mohammad Ashikur Rahman, Materials Science & Engineering, Faculty of Science, UNSW January 2009 (has links)
The aim of the project was to establish the rate and mechanisms of solid stage reduction of titania and ilmenite ores. The project examined carbothermal reduction of titania and various types of ilmenite ores in argon, helium, hydrogen, and their mixtures. Effect of CO in the gas atmosphere on reduction behavior of titania and primary ilmenite ore was also studied. Isothermal and non-isothermal reduction experiments were conducted in a fixed bed reactor in the high temperature furnace in the temperature range up to 1500oC. The off-gas composition in the reduction process was monitored by a CO/CO2/CH4 infrared analyser. The extent of reduction was calculated using data on gas composition and LECO oxygen analysis. Phase composition and morphology of reduced samples were studied using XRD, SEM and optical microscopy. The major findings of this project are as follows: The reduction of titania to titanium oxycarbide occurred in the following sequence: TiO2 → Ti5O9 → Ti4O7 → Ti3O5 → Ti2O3 → (TiO-TiC) solid solution. Carbothermal reduction of ilmenite concentrates proceeded in two main stages. In the first stage pseudorutile and ilmenite were reduced to metallic iron and titania. Second stage involved the reduction of titania to titanium oxycarbide. Rate and degree of reduction of titania and ilmenite concentrates increased with increasing temperature. Reduction rate of titania and ilmenite concentrates was faster in hydrogen than in helium and argon. The difference in the reduction behavior in helium and argon was insignificant; reduction rate of ilmenite was slightly faster in helium than in argon. High rate of reduction of titania and ilmenite in hydrogen was attributed to formation of methane which facilitated mass transfer of carbon from graphite to oxide. Hydrogen was also directly involved in reduction of titania and ilmenite concentrates; hydrogen reduced pseudorutile to iron and titania. Titania was further reduced to titanium oxycarbide by carbon through methane. Increased gas flow rate slightly improved the reduction rate in hydrogen and suppressed the reduction in inert gases. Addition of CO to hydrogen and inert gases above 3 vol% suppressed the reduction process.
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Erzeugung höchster 3He-Kernspinpolarisation durch metastabiles optisches PumpenWolf, Michael Unknown Date (has links) (PDF)
Mainz, Univ., Diss., 2004 / Erscheinungsjahr an der Haupttitelstelle: 2004
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Grundzustandskorrelationen und dynamische Prozesse untersucht in Ion-Helium-StößenSchöffler, Markus S. Unknown Date (has links)
Universiẗat, Diss., 2006--Frankfurt (Main).
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Some experiments with liquid ³He-⁴He mixtures in narrow slitsWansink, Derk Hendrik Nicolaüs, January 1900 (has links)
Proefschrift--Leiden. / "Stellingen" ([3] p.) inserted. Includes bibliographies.
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On the disappearance of superfluidity in helium filmsBannink, Gerrit, January 1983 (has links)
Thesis--Leyden. / In Periodical Room.
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Disintegration of helium by 300-Mev neutronsInnes, William Henry. January 1958 (has links)
Thesis (Ph. D. in Physics)--University of California, Berkeley, June 1958. / Includes bibliographical references (leaves 73-74).
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U-, He-chronologische Fallstudien an Eisen- und ManganerzenBrander, Thomas. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2000--Heidelberg.
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Ring laser gain media : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science, University of Canterbury /Graham, Richard January 2006 (has links)
Thesis (M. Sc.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references (p. 109-111). Also available via the World Wide Web.
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Study of reaction mechanisms and short range correlations in two nucleon emission off 4He using polarized photonsNatter, Frank Alexander. Unknown Date (has links) (PDF)
University, Diss., 2002--Tübingen.
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