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Indium dopant/defect complexes in lightly-doped ceria

Description: Four well-defined indium-dopant/lattice-defect complexes and the non-complexed substitutional indium dopant have been observed by perturbed angular correlation (PAC) spectroscopy in cerium oxide. PAC is a nuclear hyperfine experimental method that detects interactions between a radioactive probe nucleus and nearby atoms. The magnitude and symmetry of those interactions provide a signature for the electromagnetic fields at the probe nucleus. These fields are produced by the arrangement of charges and magnetic moments in the near environment of the probe, so they provide a means of identifying defect structures.
Date: January 1, 1991
Creator: Wang, Ruiping; Gardner, J.A. (Oregon State Univ., Corvallis, OR (United States). Dept. of Physics); Evenson, W.E. (Brigham Young Univ., Provo, UT (United States). Dept. of Physics) & Sommers, J.A. (Teledyne-Wah Chang, Albany, OR (United States))
Partner: UNT Libraries Government Documents Department

Measurement and modeling of advanced coal conversion processes

Description: The objectives of this study are to establish the mechanisms and rates of basic steps in coal conversion processes, to integrate and incorporate this information into comprehensive computer models for coal conversion processes, to evaluate these models and to apply them to gasification, mild gasification and combustion in heat engines. (VC)
Date: September 25, 1991
Creator: Solomon, P.R.; Serio, M.A.; Hamblen, D.G. (Advanced Fuel Research, Inc., East Hartford, CT (United States)); Smoot, L.D. & Brewster, B.S. (Brigham Young Univ., Provo, UT (United States))
Partner: UNT Libraries Government Documents Department

Measurement and modeling of advanced coal conversion processes

Description: The overall objective of this program is the development of predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. This technology is important to reduce the technical and economic risks inherent in utilizing coal, a feedstock whose variable and often unexpected behavior presents a significant challenge. This program will merge significant advances made at Advanced Fuel Research, Inc. (AFR) in measuring and quantitatively describing the mechanisms in coal conversion behavior, with technology being developed at Brigham Young University (BYU) in comprehensive computer codes for mechanistic modeling of entrained-bed gasification. Additional capabilities in predicting pollutant formation will be implemented and the technology will be expanded to fixed-bed reactors. The foundation to describe coal-specified conversion behavior is ARF's Functional Group (FG) and Devolatilization, Vaporization, and Crosslinking (DVC) models, developed under previous and on-going METC sponsored programs. These models have demonstrated the capability to describe the time dependent evolution of individual gas species, and the amount and characteristics of tar and char. The combined FG-DVC model will be integrated with BYU's comprehensive two-dimensional reactor model, PCGC-2, which is currently the most widely used reactor simulation for combustion or gasification. The program includes: (1) validation of the submodels by comparison with laboratory data obtained in this program, (2) extensive validation of the modified comprehensive code by comparison of predicted results with data from bench-scale and process scale investigations of gasification, mild gasification and combustion of coal or coal-derived products in heat engines, and (3) development of well documented user friendly software applicable to a workstation'' environment.
Date: January 1, 1990
Creator: Solomon, P.R.; Serio, M.A.; Hamblen, D.G. (Advanced Fuel Research, Inc., East Hartford, CT (United States)); Smoot, L.D. & Brewster, B.S. (Brigham Young Univ., Provo, UT (United States))
Partner: UNT Libraries Government Documents Department

Measurement and modeling of advanced coal conversion processes

Description: The objective of this study are to establish the mechanisms and rates of basic steps in coal conversion processes, to integrate and incorporate this information into comprehensive computer models for coal conversion processes, to evaluate these models and to apply them to gasification, mild gasification and combustion in heat engines.
Date: January 1, 1991
Creator: Solomon, P.R.; Serio, M.A.; Hamblen, D.G. (Advanced Fuel Research, Inc., East Hartford, CT (United States)); Smoot, L.D. & Brewster, B.S. (Brigham Young Univ., Provo, UT (United States))
Partner: UNT Libraries Government Documents Department

Measurement and modeling of advanced coal conversion processes

Description: The overall objective of this program is the development of predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. This program will merge significant advances made in measuring and quantitatively describing the mechanisms in coal conversion behavior. Comprehensive computer codes for mechanistic modeling of entrained-bed gasification. Additional capabilities in predicting pollutant formation will be implemented and the technology will be expanded to fixed-bed reactors.
Date: January 1, 1991
Creator: Solomon, P.R.; Serio, M.A.; Hamblen, D.G.; Smoot, L.D. & Brewster, B.S. (Advanced Fuel Research, Inc., East Hartford, CT (United States) Brigham Young Univ., Provo, UT (United States))
Partner: UNT Libraries Government Documents Department

Measurement and modeling of advanced coal conversion processes

Description: The overall objective of this program is the development of predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. This technology is important to reduce the technical and economic risks inherent in utilizing coal, a feedstock whose variable and often unexpected behavior presents a significant challenge. This program will merge significant advances made at Advanced Fuel Research, Inc. (AFR) in measuring and quantitatively describing the mechanisms in coal conversion behavior, with technology being developed at Brigham Young University (BYU) in comprehensive computer codes for mechanistic modeling of entrained-bed gasification. Additional capabilities in predicting pollutant formation will be implemented and the technology will be expanded to fixed-bed reactors. The foundation to describe coal-specific conversion behavior is AFR's Functional Group (FG) and Devolatilization, Vaporization and Crosslinking (DVC) models, developed under previous and on-going METC sponsored programs. These models have demonstrated the capability to describe the time dependent evolution of individual gas species, and the amount and characteristics of tar and char. The combined FG-DVC model will be integrated with BYU's comprehensive two-dimensional reactor model, PCGC-2, which is currently the most widely used reactor simulation for combustion or gasification. The program includes: (i) validation of the submodels by comparison with laboratory data obtained in this program, (ii) extensive validation of the modified comprehensive code by comparison of predicted results with data from bench-scale and process scale investigations of gasification, mild gasification and combustion of coal or coal-derived products in heat engines, and (iii) development of well documented user friendly software applicable to a workstation'' environment.
Date: January 1, 1992
Creator: Solomon, P.R.; Serio, M.A.; Hamblen, D.G. (Advanced Fuel Research, Inc., East Hartford, CT (United States)); Smoot, L.D. & Brewster, B.S. (Brigham Young Univ., Provo, UT (United States))
Partner: UNT Libraries Government Documents Department

PAC spectroscopy of electronic ceramics

Description: Dilute indium dopants in cerium oxides and YBa{sub 2}Cu{sub 3}O{sub x} have been studied by{sup 111}In/Cd Perturbed Angular Correlation (PAC) spectroscopy. By controlling oxygen vacancy concentration in the cerium oxides through doping or high-temperature vacuum annealing, we have found that indium always forms a defect complex unless the sample is doped to reduce greatly the oxygen vacancy concentration. Three different vacancy-associated complexes are found with concentrations that depend on doping and oxygen stoichiometry. Another defect complex occurs in samples having negligible vacancy concentration. At low temperatures, evidence is found of interaction with an electronic hole trapped by {sup 111}Cd after the radioactive decay of the {sup 111}In parent. In YBa{sub 2}Cu{sub 3}O{sub x} the indium substitutes preferentially at the Y site but has measurable probability of substitution in at least one of the two copper sites. A symmetry change near 650 {degree}C is consistent with the well-documented orthorhombic/tetragonal transition for samples in air or oxygen.
Date: January 1, 1991
Creator: Gardner, J.A.; Wang, Ruiping; Schwenker, R. (Oregon Univ., Eugene, OR (United States). Dept. of Physics); Evenson, W.E. (Brigham Young Univ., Provo, UT (United States). Dept. of Physics and Astronomy); Rasera, R.L. (Maryland Univ., Catonsville, MD (United States). Dept. of Physics) & Sommers, J.A. (Teledyne-Wah Chang, Albany, OR (United States))
Partner: UNT Libraries Government Documents Department

Measurement and modeling of advanced coal conversion processes, Volume III

Description: A generalized one-dimensional, heterogeneous, steady-state, fixed-bed model for coal gasification and combustion is presented. The model, FBED-1, is a design and analysis tool that can be used to simulate a variety of gasification, devolatilization, and combustion processes. The model considers separate gas and solid temperatures, axially variable solid and gas flow rates, variable bed void fraction, coal drying, devolatilization based on chemical functional group composition, depolymerization, vaporization and crosslinking, oxidation, and gasification of char, and partial equilibrium in the gas phase.
Date: August 1, 1993
Creator: Ghani, M.U.; Hobbs, M.L. & Hamblen, D.G.
Partner: UNT Libraries Government Documents Department

Measurement and modeling of advanced coal conversion processes, Volume II

Description: A two dimensional, steady-state model for describing a variety of reactive and nonreactive flows, including pulverized coal combustion and gasification, is presented. The model, referred to as 93-PCGC-2 is applicable to cylindrical, axi-symmetric systems. Turbulence is accounted for in both the fluid mechanics equations and the combustion scheme. Radiation from gases, walls, and particles is taken into account using a discrete ordinates method. The particle phase is modeled in a lagrangian framework, such that mean paths of particle groups are followed. A new coal-general devolatilization submodel (FG-DVC) with coal swelling and char reactivity submodels has been added.
Date: June 1, 1993
Creator: Solomon, P. R.; Serio, M. A. & Hamblen, D. G.
Partner: UNT Libraries Government Documents Department

Measurement and modeling of advanced coal conversion processes, Volume I, Part 1. Final report, September 1986--September 1993

Description: The objective of this program was the development of a predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. The foundation to describe coal specific conversion behavior was AFR`s Functional Group and Devolatilization, Vaporization and Crosslinking (DVC) models, which had been previously developed. The combined FG-DVC model was integrated with BYU`s comprehensive two-dimensional reactor model for combustion and coal gasification, PCGC-2, and a one-dimensional model for fixed-bed gasifiers, FBED-1. Progress utilizing these models is described.
Date: September 1, 1995
Creator: Solomon, P.R.; Serio, M.A. & Hamblen, D.G.
Partner: UNT Libraries Government Documents Department

Measurement and modeling of advanced coal conversion processes, Volume I, Part 2. Final report, September 1986--September 1993

Description: This report describes work pertaining to the development of models for coal gasification and combustion processes. This volume, volume 1, part 2, contains research progress in the areas of large particle oxidation at high temperatures, large particle, thick-bed submodels, sulfur oxide/nitrogen oxides submodels, and comprehensive model development and evaluation.
Date: September 1, 1995
Creator: Solomon, P.R.; Serio, M.A. & Hamblen, D.G.
Partner: UNT Libraries Government Documents Department