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Oxides in Pig Iron: Their Origin and Action in the Steel-Making Process

Description: From Introduction: "In summarizing the evidence in the literature it is apparent that there is general agreement among furnace men on the existence of so-called "bad-iron." It is also evident that the existence of dissolved or occluded gases is not an explanation. The presence of suspended oxides has been proved, and at least one plausible explanation for their formation has been given."
Date: 1929
Creator: Herty, C. H., Jr. & Gaines, J. M., Jr.
Partner: UNT Libraries Government Documents Department

Contributions to the Data on Theoretical Metallurgy: [Part] 12. Heats and Free Energies of Formation of Inorganic Oxides

Description: From Introduction: "This bulletin purposes to collect and compile, in readily usable form, heat and free-energy-of-formation data for inorganic oxides. Such data are used in evaluating heat balances in metallurgical processes, in appraising possible improvements in existing metal extractive methods, and as a guide in the search for better methods of producing metals of recent or possible future commercial interest."
Date: 1954
Creator: Coughlin, James P.
Partner: UNT Libraries Government Documents Department

Creep in electronic ceramics

Description: High-temperature creep measurements combined with microstructural investigations can be used to elucidate deformation mechanisms that can be related to the diffusion kinetics and defect chemistry of the minority species. This paper will review the theoretical basis for this correlation and illustrate it with examples from some important electronic ceramics having a perovskite structure. Recent results on BaTiO{sub 3}, (La{sub 1{minus}x}Sr){sub 1{minus}y}MnO{sub 3+{delta}}, YBa{sub 2}Cu{sub 3}O{sub x}, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x}, (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} and Sr(Fe,Co){sub 1.5}O{sub x} will be presented.
Date: April 27, 2000
Creator: Routbort, J. L.; Goretta, K. C. & Arellano-Lopez, A. R.
Partner: UNT Libraries Government Documents Department

Phase relationships and cation disorder in RE{sub 1+x}Ba{sub 2-x}Cu{sub 3}O{sub 7+{delta}}, RE = Pr, Nd, Sm, Gd

Description: Unlike Y123 which forms only a stoichiometric compound, the light arare earth elements (LRE) form a solid solution LRE{sub 1+x}Ba{sub 2-x}Cu{sub 3}O{sub 7+{delta}} (LRE123ss), with increasing substitution of the LRE{sup 3+} for the Ba{sup 2+} as the ionic radii of the LRE increases. The sub-solidus phase relationships around the LRE123ss change for La, Pr and Nd, but are similar for Sm and Gd. However, the solubility limit decreases with decreasing ionic radii. In addition, the solubility limits for Sm and Gd are strongly influenced by PO{sub 2} during high temperature annealing. The range of solubility is, for any given LRE system, strongly dependent on the oxygen partial pressure (PO{sub 2}) providing a new means by which to control the microstructure in the RE123 system.
Date: December 31, 1995
Creator: Kramer, M.J.; Wu, H.; Dennis, K.W.; Polzin, B.I.; Falzgraf, D.K. & McCallum, R.W.
Partner: UNT Libraries Government Documents Department

Magnetic and Charge Fluctuations in High-T(Sub c) Superconductors

Description: Neutron scattering has been used to study the spin fluctuations in the YBaCuO and BiSrCaCuO materials. Evidence is found for both incommensurate fluctuations and a commensurate resonance excitation. Measurements on the lattice dynamics for YBaCuO show incommensurate structure that appears to stem from charge fluctuations that are associated with the spin fluctuations.
Date: June 2, 1998
Creator: Chakoumakos, B.C.; Dogan, F. & Mook, H.A.
Partner: UNT Libraries Government Documents Department

Phase formation and superconductivity in PIT-type (Bi,Pb)-1212

Description: It was shown via powder-in-tube (PIT) processing that the (Bi,Pb)-1212 phase readily forms inside a silver sheath at 920 C in air. Composition, oxygen pressure, time, and temperature were all varied to study their effects on (Bi,Pb)-1212 phase purity and superconductivity.
Date: January 13, 2000
Creator: Murphy, N. M.; Dorris, S. E.; Miller, D. J.; Luo, Z. P.; Claus, H. & Maroni, V. A.
Partner: UNT Libraries Government Documents Department

Experimental Evidence for Topological Doping in the Cuprates

Description: Some recent experiments that provide support for the concept of topological doping in cuprate superconductors are discussed. Consistent with the idea of charge segregation, it is argued that the scattering associated with the ''resonance'' peak found in YBa{sub 2}Cu{sub 3}O{sub 6+x} and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} comes from the Cu spins and not from the doped holes.
Date: April 6, 1999
Creator: Tranquada, J. M.
Partner: UNT Libraries Government Documents Department

Pressure as a probe of the physics of relaxor ferroelectrics

Description: Pressure studies have provided new insights into the physics of compositionally-disordered ABO{sub 3} oxide relaxors. Specifically, results will be presented and discussed on a pressure-induced ferroelectric-to-relaxer crossover phenomenon, the continuous evolution of the energetic and dynamics of the relaxation process, and the interplay between pressure and electric field in determining the dielectric response.
Date: January 25, 2000
Creator: SAMARA,GEORGE A.
Partner: UNT Libraries Government Documents Department

Uniformly Reactive Uranium Dioxide from a Single Oxidation-Reduction Cycle

Description: Abstract: By use of a modified thermobalance and reactor as the primary experimental tool for sample preparation and evaluation, a process has been developed by which parent uranium feed materials of a widely variable reactivity and composition may be converted to a uniformly reactive uranium dioxide.
Date: August 28, 1963
Creator: Orrick, N. C.; Jones, C. G.; Hale, C. F.; Barber, E. J. & Rapp, Karl E.
Partner: UNT Libraries Government Documents Department

HIGH RESOLUTION PHOTOEMISSION STUDIES OF COMPLEX MATERIALS.

Description: Recent instrumentation developments in photoemission are providing new insights into the physics of complex materials. With increased energy and momentum resolution, it has become possible to examine in detail different contributions to the self-energy or inverse lifetime of the photohole created in the photoexcitation process, Employing momentum distribution and energy distribution curves, a detailed study of the optimally doped cuprate, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub g+{delta}}, shows that the material behaves like a non-Fermi liquid with no evidence for the quasi-particles characteristic of a Fermi liquid.
Date: October 13, 1999
Creator: JOHNSON,P.D.
Partner: UNT Libraries Government Documents Department

A{sub 2}Zn{sub 3}As{sub 2}O{sub 2}(A = Ba, Sr): a rare example of square planar zinc

Description: Purpose of this study was to explore synthesis of novel solid-state compounds that could potentially exhibit interesting or useful physical properties. Goal was to extend the classes of compounds A{sub 2}Mn{sub 3}Pn{sub 2}O{sub 2} (A=Sr,Ba; Pn=P,As,Sb,Bi) to include a transition metal other than Mn. High-temperature fluxes were used to produce these new compounds.
Date: June 1994
Creator: Keane, P. M. & Burdett, J. K.
Partner: UNT Libraries Government Documents Department

CERIUM AND PLUTONIUM DIOXIDE--NOTES ON REDUCTION TO MASSIVE METAL

Description: In reduction reactions of CeO/sub 2/, with calcium and a CaCl/sub 2/ flux, the use of vibrational energy was shown to have a marked effect on the yield of coalesced metal. Buttons of 40 to 50% theoretical yield were obtained from the vibrated reductions. As the flux concentration is decreased, the slag becomes more viscous containing undissolved CaO. The undissolved CaO present prevents the metal from completely coalescing, but the metal can be recovered from the slag and coalesced under CaCl/sub 2/ containing a small amount of calcium to reduce any oxide skin present. Cerium pellet yields of 50 to 60% metal were obtained by the procedure and were not difficult to handle in air. Cerium was used as a stand-in material for plutonium. (B.O.G.)
Date: February 13, 1956
Creator: Tolley, W. B.
Partner: UNT Libraries Government Documents Department

Measurement of the critical current and transient characteristics of a high-temperature superconductor tube using a pulsed current supply.

Description: The transient response of a melt-cast-processed BSCCO-2212 superconductor tube is investigated by using a pulsed current source. It was found that (1) the maximum induced current and the excitation current at field penetration increase with the maximum excitation current, and (2) there is a time delay between peak excitation current and peak magnetic field inside the superconductor. These observations can be explained by the concept of magnetic diffusion. The ac steady-state critical current of the superconductor was found to depend on the magnitude of the current increment. The critical current determined by using the pulsed current system agrees fairly well with the ac steady-state critical current determined by using relatively large current increment.
Date: August 27, 1998
Creator: Cha, Y. S.
Partner: UNT Libraries Government Documents Department