Aluminum Carbothermic Technology (open access)

Aluminum Carbothermic Technology

This report documents the non-proprietary research and development conducted on the Aluminum Carbothermic Technology (ACT) project from contract inception on July 01, 2000 to termination on December 31, 2004. The objectives of the program were to demonstrate the technical and economic feasibility of a new carbothermic process for producing commercial grade aluminum, designated as the ''Advanced Reactor Process'' (ARP). The scope of the program ranged from fundamental research through small scale laboratory experiments (65 kW power input) to larger scale test modules at up to 1600 kW power input. The tasks included work on four components of the process, Stages 1 and 2 of the reactor, vapor recovery and metal alloy decarbonization; development of computer models; and economic analyses of capital and operating costs. Justification for developing a new, carbothermic route to aluminum production is defined by the potential benefits in reduced energy, lower costs and more favorable environmental characteristics than the conventional Hall-Heroult process presently used by the industry. The estimated metrics for these advantages include energy rates at approximately 10 kWh/kg Al (versus over 13 kWh/kg Al for Hall-Heroult), capital costs as low as $1250 per MTY (versus 4,000 per MTY for Hall-Heroult), operating cost reductions of over …
Date: March 31, 2005
Creator: Bruno, Marshall J.
Object Type: Report
System: The UNT Digital Library
Ammonia-Free NOx Control System (open access)

Ammonia-Free NOx Control System

Research is being conducted under United States Department of Energy (DOE) Contract DE-FC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia.
Date: March 31, 2005
Creator: Wu, Song; Fan, Zhen; Seltzer, Andrew H. & Herman, Richard G.
Object Type: Report
System: The UNT Digital Library
Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1 - March 31, 2005 (open access)

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1 - March 31, 2005

Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. The United States Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for this second quarter for the Southern Great Plains (SGP) site is 2052 hours (0.95 × 2,160 hours this quarter). The annual OPSMAX for the North Slope Alaska (NSA) site is 1944 hours (0.90 × …
Date: March 31, 2005
Creator: Sisterson, D. L.
Object Type: Report
System: The UNT Digital Library
Basin Analysis and Petroleum System Characterization and Modeling, Interior Salt Basins, Central and Eastern Gulf of Mexico (open access)

Basin Analysis and Petroleum System Characterization and Modeling, Interior Salt Basins, Central and Eastern Gulf of Mexico

The principal research effort for Year 2 of the project is the determination of the burial and thermal maturation histories and basin modeling and petroleum system identification of the North Louisiana Salt Basin. In the first six (6) to nine (9) months of Year 2, the research focus is on the determination of the burial and thermal maturation histories and the remainder of the year the emphasis is on basin modeling and petroleum system identification. No major problems have been encountered to date, and the project is on schedule.
Date: March 31, 2005
Creator: Mancini, Ernest A.
Object Type: Report
System: The UNT Digital Library
C1 Chemistry for the Production of Ultra-Clean Liquid Transportation Fuels and Hydrogen (open access)

C1 Chemistry for the Production of Ultra-Clean Liquid Transportation Fuels and Hydrogen

Faculty and students from five universities--the University of Kentucky, University of Pittsburgh, University of Utah, West Virginia University, and Auburn University--are collaborating in a research program to develop C1 chemistry processes to produce ultra-clean liquid transportation fuels and hydrogen, the zero-emissions transportation fuel of the future. The feedstocks contain one carbon atom per molecular unit. They include synthesis gas (syngas), a mixture of carbon monoxide and hydrogen produced by coal gasification or reforming of natural gas, methane, methanol, carbon dioxide, and carbon monoxide. An important objective is to develop C1 technology for the production of liquid transportation fuel and hydrogen from domestically plentiful resources such as coal, coalbed methane, and natural gas. An Industrial Advisory Board with representatives from Chevron-Texaco, Eastman Chemical, Conoco-Phillips, the Air Force Research Laboratory, the U.S. Army National Automotive Center (Tank & Automotive Command--TACOM), and Tier Associates provides guidance on the practicality of the research. The current report presents results obtained in this research program during the six months of the subject contract from October 1, 2002 through March 31, 2003. The results are presented in thirteen detailed reports on research projects headed by various faculty members at each of the five CFFS Universities. Additionally, an …
Date: March 31, 2005
Creator: Huffman, Gerald P.
Object Type: Report
System: The UNT Digital Library
Calibration and Testing of Sonic Stimulation Technologies (open access)

Calibration and Testing of Sonic Stimulation Technologies

In conjunction with Baker Atlas Inc. Michigan Technological University devised a system capable of recording the earth motion and pressure due to downhole and surface seismic sources. The essential elements of the system are 1) a borehole test site that will remain constant and is available all the time and for any length of time, 2) a downhole sonde that will itself remain constant and, because of its downhole digitization feature, does not require the wireline or surface recording components to remain constant, and 3) a set of procedures that ensures that the amplitude and frequency parameters of a wide range of sources can be compared with confidence. This system was used to record four seismic sources, three downhole sources and one surface source. A single activation of each of the downhole sources was not seen on time traces above the ambient noise, however, one sweep of the surface source, a small vertical vibrator, was easily seen in a time trace. One of the downhole sources was seen by means of a spike in its spectrum and a second downhole source was clearly seen after correlation and stacking. The surface vibrator produced a peak to peak particle motion signal of …
Date: March 31, 2005
Creator: Turpening, Roger M. & D.Pennington, Wayne
Object Type: Report
System: The UNT Digital Library
Castability Assessment and Data Integration (open access)

Castability Assessment and Data Integration

The report is divided into two sections. The first section deals with Equilibrium Analysis and Fill Pattern Reasoning for Die Casting Process. The second section covers Graphical User Interface for Cooling Line Functions and Surface Rendering.
Date: March 31, 2005
Creator: Miller, R. Allen
Object Type: Report
System: The UNT Digital Library
Characterization of Pump Flow at the Grand Coulee Pumping Station for Fish Passage, 2004 (open access)

Characterization of Pump Flow at the Grand Coulee Pumping Station for Fish Passage, 2004

This report describes a study conducted by PNNL for the Bonneville Power Administration to characterized the conditions fish experience when entrained in pump flow at the Grand Coulee Dam. PNNL used the Sensor Fish to measure the acceleration and pressure conditions that might be experienced by fish who are pulled through the pumps and turbines at Grand Coulee Dam's pump generation station and transported up into the feeder canal leading to Banks Lake. The probability that fish would be struck by the pump generating plant's new 9-bladed turbines was also calculated using Monte Carlo simulations. Our measurements showed relatively low turbulence except in the immediate vicinity of the runner environment. The highest pressure experienced by the Sensor Fish was estimated at 157 psi (the pressure gauge saturated at 155 psi). The probability of strike was also calculated, based on the average length of hatchery-reared juvenile kokanee (land-locked sockeye). Strike probabilities ranged from 0.755 for 2.36-inch fish to 0.3890 for 11.8-inch fish. The probability of strike estimates indicate that the majority (77%) of kokanne would be carried through the pump without being struck and most likely without injury resulting from pressure and turbulence exposure. Of the 23% that might be struck …
Date: March 31, 2005
Creator: Carlson, Thomas J.; Duncan, Joanne P. & Johnson, Robert L.
Object Type: Report
System: The UNT Digital Library
Clean Diesel Engine Component Improvement Program Diesel Truck Thermoelectric Generator (open access)

Clean Diesel Engine Component Improvement Program Diesel Truck Thermoelectric Generator

Hi-Z Technology, Inc. (Hi-Z) is currently developing four different auxiliary generator designs that are used to convert a portion (5 to 20%) of the waste heat from vehicle engines exhaust directly to electricity. The four designs range from 200 Watts to 10 kW. The furthest along is the 1 kW Diesel Truck Thermoelectric Generator (DTTEG) for heavy duty Class 8 Diesel trucks, which, under this program, has been subjected to 543,000 equivalent miles of bouncing and jarring on PACCAR’s test track. Test experience on an earlier version of the DTTEG on the same track showed the need for design modifications incorporated in DTTEG Mod 2, such as a heavy duty shock mounting system and reinforcement of the electrical leads mounting system, the thermocouple mounting system and the thermoelectric module restraints. The conclusion of the 543,000 mile test also pointed the way for an upgrading to heavy duty hose or flex connections for the internal coolant connections for the TEG, and consideration of a separate lower temperature cooling loop with its own radiator. Fuel savings of up to $750 per year and a three to five year payback are believed to be possible with the 5 % efficiency modules. The economics …
Date: March 31, 2005
Creator: Elsner, N.B.; Bass, J.C.; Ghamaty, S.; Krommenhoek, D.; Kushch, A.; Snowden, D. et al.
Object Type: Report
System: The UNT Digital Library
Combustion Turbine (CT) Hot Section Coating Life Management (open access)

Combustion Turbine (CT) Hot Section Coating Life Management

The integrity of coatings used in hot section components of combustion turbines is crucial to the reliability of the buckets. This project was initiated in recognition of the need for predicting the life of coatings analytically, and non-destructively; correspondingly, four principal tasks were established. Task 1, with the objective of analytically developing stress, strain and temperature distributions in the bucket and thereby predicting thermal fatigue (TMF) damage for various operating conditions; Task 2 with the objective of developing eddy current techniques to measure both TMF damage and general degradation of coatings and, Task 3 with the objective of developing mechanism based algorithms. Task 4 is aimed at verifying analytical predictions from Task 1 and the NDE predictions from Task 3 against field observations.
Date: March 31, 2005
Creator: Cheruvu, S. & Krzywosz, K.
Object Type: Report
System: The UNT Digital Library
Comprehensive Renewable Energy Feasibility Study for the Makah Indian Tribe (open access)

Comprehensive Renewable Energy Feasibility Study for the Makah Indian Tribe

The purpose of this project was to determine the technical feasibility, economic viability, and potential impacts of installing and operating a wind power station and/or small hydroelectric generation plants on the Makah reservation. The long-term objective is to supply all or a portion of Tribe's electricity from local, renewable energy sources in order to reduce costs, provide local employment, and reduce power outages. An additional objective was for the Tribe to gain an understanding of the requirements, costs, and benefits of developing and operating such plants on the reservation. The Makah Indian Reservation, with a total land area of forty-seven square miles, is located on the northwestern tip of the Olympic Peninsula in Washington State. Four major watersheds drain the main Reservation areas and the average rainfall is over one hundred inches per year. The reservation's west side borders the Pacific Ocean, but mostly consists of rugged mountainous terrain between 500 and 1,900 feet in elevation. Approximately 1,200 tribal members live on the Reservation and there is an additional non-Indian residential population of about 300. Electric power is provided by the Clallam County PUD. The annual usage on the reservation is approximately 16,700 mWh. Project Work Wind Energy--Two anemometer suites …
Date: March 31, 2005
Creator: RobertLynette; Wade, John & Coupe, Larry
Object Type: Report
System: The UNT Digital Library
Conference Paper/Proceedings White Paper Conference Results of March 3, 2005 Workshop in Irvine, CA (open access)

Conference Paper/Proceedings White Paper Conference Results of March 3, 2005 Workshop in Irvine, CA

A one-day workshop sponsored by UC Irvine's Center for Urban Infrastructure, bringing together 20 state departments of transportation and environmental quality to discuss national coordination on alternative fuels.
Date: March 31, 2005
Creator: Redman, Deborah Hart & Catz, Sarah L.
Object Type: Article
System: The UNT Digital Library
Contaminants of Potential Concern in the 300-FF-5 Operable Unit: Expanded Annual Groundwater Report for Fiscal Year 2004 (open access)

Contaminants of Potential Concern in the 300-FF-5 Operable Unit: Expanded Annual Groundwater Report for Fiscal Year 2004

This report satisfies requirements in the Operations and Maintenance Plan for the 300-FF-5 Operable Unit (DOE/RL-95-73, Rev. 1) to provide detailed information, beyond that provided in the regular annual groundwater report (e.g., PNNL-15070), on groundwater conditions. The purpose is to characterize current conditions; provide a basis for changes to the monitoring schedules; and provide technical information to support the second 5-year review of the record-of-decision for the operable unit. Key topics include historical trends in the levels of various contaminants; updating the list of contaminants of potential concern; conceptual site models for uranium (300 Area) and tritium (618-11 waste site sub-region); performance of the interim actions under the current record-of-decision; and analysis of the applicability of Monitored Natural Attenuation as a remedial action alternative.
Date: March 31, 2005
Creator: Peterson, Robert E.; Freeman, Eugene J.; Thorne, Paul D.; Williams, Mark D.; Lindberg, Jon W.; Murray, Christopher J. et al.
Object Type: Report
System: The UNT Digital Library
Design, Fabrication and Testing of an Infrared Ratio Pyrometer System for the Measurement of Gasifier Reaction Chamber Temperature (open access)

Design, Fabrication and Testing of an Infrared Ratio Pyrometer System for the Measurement of Gasifier Reaction Chamber Temperature

Texaco was awarded contract DE-FC26-99FT40684 from the U.S. DOE to design, build, bench test and field test an infrared ratio pyrometer system for measuring gasifier temperature. The award occurred in two phases. Phase 1, which involved designing, building and bench testing, was completed in September 2000, and the Phase 1 report was issued in March 2001. Phase 2 was completed in 2005, and the results of the field test are contained in this final report. Two test campaigns were made. In the first one, the pyrometer was sighted into the gasifier. It performed well for a brief period of time and then experienced difficulties in keeping the sight tube open due to a slag accumulation which developed around the opening of the sight tube in the gasifier wall. In the second test campaign, the pyrometer was sighted into the top of the radiant syngas cooler through an unused soot blower lance. The pyrometer experienced no more problems with slag occlusions, and the readings were continuous and consistent. However, the pyrometer readings were 800 to 900 F lower than the gasifier thermocouple readings, which is consistent with computer simulations of the temperature distribution inside the radiant syngas cooler. In addition, the …
Date: March 31, 2005
Creator: Leininger, Tom
Object Type: Report
System: The UNT Digital Library
DESIGN, SYNTHESIS, AND MECHANISTIC EVALUATION OF IRON-BASED CATALYSIS FOR SYNTHESIS GAS CONVERSION TO FUELS AND CHEMICALS (open access)

DESIGN, SYNTHESIS, AND MECHANISTIC EVALUATION OF IRON-BASED CATALYSIS FOR SYNTHESIS GAS CONVERSION TO FUELS AND CHEMICALS

This project explores the extension of previously discovered Fe-based catalysts to hydrogen-poor synthesis gas streams derived from coal and biomass sources. These catalysts have previously shown unprecedented Fischer-Tropsch synthesis rate, selectivity with synthesis gas derived from methane. During the first reporting period, we certified a microreactor, installed required analytical equipment, and reproduced synthetic protocols and catalytic performance previously reported. During the second reporting period, we prepared several Fe-based compositions for Fischer-Tropsch synthesis and tested the effects of product recycle under both subcritical and supercritical conditions. During this third reporting period, we have prepared a large number of Fe-based catalyst compositions using precipitation and impregnations methods with both supercritical and subcritical drying and with the systematic use of surface active agents to prevent pore collapse during drying steps required in synthetic protocols. These samples were characterized during this period using X-ray diffraction, surface area, and temperature-programmed reduction measurements. These studies have shown that these synthesis methods lead to even higher surface areas than in our previous studies and confirm the crystalline structures of these materials and their reactivity in both oxide-carbide interconversions and in Fischer-Tropsch synthesis catalysis. Fischer-Tropsch synthesis reaction rates and selectivities with low H{sub 2}/CO ratio feeds (H{sub 2}/CO …
Date: March 31, 2005
Creator: Ishikawa, Akio; Ojeda, Manuel & Iglesia, Enrique
Object Type: Report
System: The UNT Digital Library
Detection and Classification of Buried Metallic Objects UX-1225 (open access)

Detection and Classification of Buried Metallic Objects UX-1225

In summary the technical objectives of this project were: (1) To develop and demonstrate a methodology for the quantitative evaluation of existing active electromagnetic (AEM) systems and for the design of new systems. (2) To implement a new methodology for optimizing an AEM system for detecting and classifying UXO of a given class in a specified geologic setting and in a given noise environment. (3) To design and build a prototype of an active EM system for detecting and characterizing a metallic object in the ground.
Date: March 31, 2005
Creator: Morrison, Frank; Smith, Torquil; Becker, Alex & Gasperikova, Erika
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS (open access)

DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently hampered by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are …
Date: March 31, 2005
Creator: Paulsson, Bjorn N.P.
Object Type: Report
System: The UNT Digital Library
Development of a New Class of Fe-3Cr-W(V)Ferritic STeels for Industrial Process Applications (open access)

Development of a New Class of Fe-3Cr-W(V)Ferritic STeels for Industrial Process Applications

The project described in this report dealt with improving the materials performance and fabrication for hydrotreating reactor vessels, heat recovery systems, and other components for the petroleum and chemical industries. The petroleum and chemical industries use reactor vessels that can approach ship weights of approximately 300 tons with vessel wall thicknesses of 3-8 in. These vessels are typically fabricated from Fe-Cr-Mo steels with chromium ranging from 1.25 to 12% and molybdenum from 1 to 2%. Steels in this composition range have great advantages of high thermal conductivity, low thermal expansion, low cost, and good properties obtainable by heat treatment. With all of the advantages of Fe-Cr-Mo steels, several issues are faced in design and fabrication of vessels and related components. These issues include the following: 1. The low strengths of current alloys require thicker sections. 2. Increased thickness causes heat-treatment issues related to nonuniformity across the thickness and thus a failure to achieve optimum properties. 3. Fracture toughness (ductile-to-brittle transition) is a critical safety issue for these vessels, especially in thick sections because of the nonuniformity of the microstructure. 4. The postweld heat treatment (PWHT) needed after welding makes fabrication more timeconsuming with increased cost. 5. PWHT needed after welding …
Date: March 31, 2005
Creator: Jawad, M.
Object Type: Report
System: The UNT Digital Library
Development of a Novel Catalyst for NO Decomposition (open access)

Development of a Novel Catalyst for NO Decomposition

Air pollution arising from the emission of nitrogen oxides as a result of combustion taking place in boilers, furnaces and engines, has increasingly been recognized as a problem. New methods to remove NO{sub x} emissions significantly and economically must be developed. The current technology for post-combustion removal of NO is the selective catalytic reduction (SCR) of NO by ammonia or possibly by a hydrocarbon such as methane. The catalytic decomposition of NO to give N{sub 2} will be preferable to the SCR process because it will eliminate the costs and operating problems associated with the use of an external reducing species. The most promising decomposition catalysts are transition metal (especially copper)-exchanged zeolites, perovskites, and noble metals supported on metal oxides such as alumina, silica, and ceria. The main shortcoming of the noble metal reducible oxide (NMRO) catalysts is that they are prone to deactivation by oxygen. It has been reported that catalysts containing tin oxide show oxygen adsorption behavior that may involve hydroxyl groups attached to the tin oxide. This is different than that observed with other noble metal-metal oxide combinations, which have the oxygen adsorbing on the noble metal and subsequently spilling over to the metal oxide. This observation …
Date: March 31, 2005
Creator: Akyurtlu, Ates & Akyurtlu, Jale F
Object Type: Report
System: The UNT Digital Library
Electrons and gas versus high brightness ion beams (open access)

Electrons and gas versus high brightness ion beams

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Date: March 31, 2005
Creator: Molvik, A. W.; Cohen, R. H.; Bieniosek, F.; Friedman, A.; Kireeff Covo, M.; Lund, S. M. et al.
Object Type: Article
System: The UNT Digital Library
Environmental Biosciences Program Third Quarter Report, Year 2 (open access)

Environmental Biosciences Program Third Quarter Report, Year 2

In May 2002, the United States Department of Energy (DOE) signed Assistance Instrument Number DE-FC09-02CH11109 with the Medical University of South Carolina (MUSC) to support the Environmental Biosciences Program (EBP). This funding instrument replaces DOE Assistance Instrument Number DE-FC02-98CH10902. EBP is an integrated, multidisciplinary scientific research program, employing a range of research initiatives to identify, study and resolve environmental health risks. These initiatives are consistent with the MUSC role as a comprehensive state-supported health sciences institution and with the nation's need for new and better approaches to the solution of a complex and expansive array of environment-related health problems. The intrinsic capabilities of a comprehensive health sciences institution enable MUSC to be a national resource for the scientific investigation of environmental health issues. EBPs success as a nationally prominent research program is due, in part, to its ability to task-organize scientific expertise from multiple disciplines in addressing these complex problems Current research projects have focused EBP talent and resources on providing the scientific basis for risk-based standards, risk-based decision making and the accelerated clean-up of widespread environmental hazards. These hazards include trichloroethylene (TCE), polychlorinated biphenyls (PCBs), and low-dose ionizing radiation. A project is also being conducted in the use of …
Date: March 31, 2005
Creator: Mohr, Lawrence C.
Object Type: Text
System: The UNT Digital Library
Evolving Dark Energy with w =/ -1 (open access)

Evolving Dark Energy with w =/ -1

Theories of evolving quintessence are constructed that generically lead to deviations from the w = -1 prediction of non-evolving dark energy. The small mass scale that governs evolution, m_\phi \approx 10^-33 eV, is radiatively stable, and the"Why Now?'' problem is solved. These results rest crucially on seesaw cosmology: in broad outline, fundamental physics and cosmology can be understood from only two mass scales, the weak scale, v, and the Planck scale, M. Requiring a scale of dark energy \rho_DE^1/4 governed by v^2/M, and a radiatively stable evolution rate m_\phi given by v^4/M^3, leads to a distinctive form for the equation of state w(z) that follows from a cosine quintessence potential. An explicit hidden axion model is constructed. Dark energy resides in the potential of the axion field which is generated by a new QCD-like force that gets strong at the scale \Lambda \approx v^2/M \approx \rho_DE^1/4. The evolution rate is given by a second seesaw that leads to the axion mass, m_\phi \approx \Lambda^2/f, with f \approx M.
Date: March 31, 2005
Creator: Hall, Lawrence J.; Nomura, Yasunori & Oliver, Steven J.
Object Type: Article
System: The UNT Digital Library
Exploring Ultrahigh Magnetic Field Processing of Materials for Developing Customized Microstructures and Enhanced Performance (open access)

Exploring Ultrahigh Magnetic Field Processing of Materials for Developing Customized Microstructures and Enhanced Performance

Thermodynamic calculations based on Gibbs free energy in the magnetization-magnetic intensity-temperature (M-H-T) magnetic equation of state space demonstrate that significantly different phase equilibria may result for those material systems where the product and parent phases exhibit different magnetization responses. These calculations show that the Gibbs free energy is changed by a factor equal to -MdH, where M and H are the magnetization and applied field strength, respectively. Magnetic field processing is directly applicable to a multitude of alloys and compounds for dramatically influencing phase stability and phase transformations. This ability to selectively control microstructural stability and alter transformation kinetics through appropriate selection of the magnetic field strength promises to provide a very robust mechanism for developing and tailoring enhanced microstructures (and even nanostructures through accelerated kinetics) with superior properties for a broad spectrum of material applications. For this Industrial Materials for the Future (IMF) Advanced Materials for the Future project, ferrous alloys were studied initially since this alloy family exhibits ferromagnetism over part of its temperature range of stability and therefore would demonstrate the maximum impact of this novel processing mechanism. Additionally, with these ferrous alloys, the high-temperature parent phase, austenite, exhibits a significantly different magnetization response from the potential …
Date: March 31, 2005
Creator: Ludtka, GERALD M.
Object Type: Report
System: The UNT Digital Library
Fate of the Epsilon Phase in the Oklo Natural Reactors (open access)

Fate of the Epsilon Phase in the Oklo Natural Reactors

In spent nuclear fuel (SNF), the micron- to submicron-sized epsilon phase (Mo-Ru-Pd-Tc-Rh) is an important host of {sup 99}Tc which has a long half life (2.13 x 10{sup 5} years) and can be an important contributor to dose in safety assessments of nuclear waste repositories. In addition, Tc is predominantly present as TcO{sub 4}{sup -} under oxidizing conditions at wide range of pH, weakly adsorbed onto mineral surfaces, and unlikely to be incorporated into alteration uranyl minerals. In the Oklo natural reactor (2.0 Ga), essentially all of the {sup 99}Tc has decayed to {sup 99}Ru. Thus, this study focuses on Ru and the other metals of the epsilon phase in order to investigate the occurrence and the fate of the epsilon phase during the corrosion of this natural SNF. Samples from reactor zone (RZ)-10 (836, 819, 687); from RZ-13 (864, 910); were investigated using TEM (transmission electron microscopy). Within the UO{sub 2} matrix, a Bi-Pd particle (40-60 nm), fioodite, PdBi{sub 2}, was observed with trace amounts of As, Fe, and Te surrounded by an amorphous Pb-rich area. (Pd,Rh){sub 2}As, palladodymite or rhodarsenide, was observed (400-500 nm in size). Ruthenarsinite, (Ru,Ni)As, was identified in most samples: with a representative composition of …
Date: March 31, 2005
Creator: Utsunomiya, S. & Ewing, R. C.
Object Type: Report
System: The UNT Digital Library