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The Influence of Radiation on Pit Solution Chemistry as it Pertains to the Transition from Metastable to Stable Pitting in Steels.
Previous work relevant to current efforts is summarized. A description of an improved version of a new electrochemical probe, the ArtPit, is given. The distinct feature of the probe for investigating metastable pitting of carbon steels is specified and compared to other approaches. The electrochemical response of the ArtPit under the gamma irradiation and elevated temperature conditions that occur at high level waste (HLW) storage tanks is presented. In particular, the Tafel slope determinations and chemical analyses of the ArtPit confined volume electrolyte are described. Based on results a possible approach for reducing the corrosion rate of HLW tank walls is suggested. Additional statistical analysis of the occurrence of short duration (passivated pits) and long term (stable pitting) electrochemical pulses (current surges) during exposure confirm that radiation enhances the occurrence of both more and smaller sized pits due to increased likelihood of repassivation.
Date:
December 31, 2006
Creator:
Galuszka-Muga, Barbara & Muga, Luis M.
Object Type:
Report
System:
The UNT Digital Library
An Integrated Approach to Characterizing Bypassed Oil in Heterogeneous and Fractured Reservoirs Using Partitioning Tracers
We explore the use of efficient streamline-based simulation approaches for modeling partitioning interwell tracer tests in hydrocarbon reservoirs. Specifically, we utilize the unique features of streamline models to develop an efficient approach for interpretation and history matching of field tracer response. A critical aspect here is the underdetermined and highly ill-posed nature of the associated inverse problems. We have investigated the relative merits of the traditional history matching ('amplitude inversion') and a novel travel time inversion in terms of robustness of the method and convergence behavior of the solution. We show that the traditional amplitude inversion is orders of magnitude more non-linear and the solution here is likely to get trapped in local minimum, leading to inadequate history match. The proposed travel time inversion is shown to be extremely efficient and robust for practical field applications. The streamline approach is generalized to model water injection in naturally fractured reservoirs through the use of a dual media approach. The fractures and matrix are treated as separate continua that are connected through a transfer function, as in conventional finite difference simulators for modeling fractured systems. A detailed comparison with a commercial finite difference simulator shows very good agreement. Furthermore, an examination of …
Date:
December 31, 2006
Creator:
Datta-Gupta, Akhil
Object Type:
Report
System:
The UNT Digital Library
INVESTIGATION OF THE TRANSFORMATION OF URANIUM UNDER IRON-REDUCING CONDITIONS: REDUCTION OF UVI BY BIOGENIC FEII/FEIII HYDROXIDE (GREEN RUST)
The recent identification of green rusts (GRs) as products of the reduction of FeIII oxyhydroxides by dissimilatory iron-reducing bacteria, coupled with the ability of synthetic (GR) to reduce UVI species to insoluble UO2, suggests that biogenic green rusts (BioGRs) may play an important role in the speciation (and thus mobility) of U in FeIII-reducing environments. The objective of our research was to examine the potential for BioGR to affect the speciation of U under FeIII-reducing conditions. To meet this objective, we designed and executed a hypothesis-driven experimental program to identify key factors leading to the formation of BioGRs as products of dissimilatory FeIII reduction, to determine the key factors controlling the reduction of UVI to UIV by GRs, and to identify the resulting U-bearing mineral phases. The results of this research significantly increase our understanding of the coupling of biotic and abiotic processes with respect to the speciation of U in iron-reducing environments. In particular, the reduction of UVI to UIV by BioGR with the subsequent formation of U-bearing mineral phases may be effective for immobilizing U in suboxic subsurface environments. This information has direct applications to contaminant transport modeling and bioremediation engineering for natural or enhanced in situ remediation …
Date:
December 31, 2006
Creator:
O'Loughlin, Edward J.; Scherer, Michelle M. & Kemner, Kenneth M.
Object Type:
Report
System:
The UNT Digital Library
Joining of Tungsten Armor Using Functional Gradients
The joining of low thermal expansion armor materials such as tungsten to high thermal expansion heat sink materials has been a major problem in plasma facing component (PFC) development. Conventional planar bonding techniques have been unable to withstand the high thermal induced stresses resulting from fabrication and high heat flux testing. During this investigation, innovative functional gradient joints produced using vacuum plasma spray forming techniques have been developed for joining tungsten armor to copper alloy heat sinks. A model was developed to select the optimum gradient architecture. Based on the modeling effort, a 2mm copper rich gradient was selected. Vacuum plasma pray parameters and procedures were then developed to produce the functional gradient joint. Using these techniques, dual cooling channel, medium scale mockups (32mm wide x 400mm length) were produced with vacuum plasma spray formed tungsten armor. The thickness of the tungsten armor was up to 5mm thick. No evidence of debonding at the interface between the heat sink and the vacuum plasma sprayed material was observed.
Date:
December 31, 2006
Creator:
O'Dell, John Scott
Object Type:
Report
System:
The UNT Digital Library
JV Task 5 - Evaluation of Residual Oil Fly Ash As A Mercury Sorbent For Coal Combustion Flue Gas
The mercury adsorption capacity of a residual oil fly ash (ROFA) sample collected form Florida Power and Light Company's Port Everglades Power Plant was evaluated using a bituminous coal combustion flue gas simulator and fixed-bed testing protocol. A size-segregated (>38 {micro}g) fraction of ROFA was ground to a fine powder and brominated to potentially enhance mercury capture. The ROFA and brominated-ROFA were ineffective in capturing or oxidizing the Hg{sup 0} present in a simulated bituminous coal combustion flue gas. In contrast, a commercially available DARCO{reg_sign} FGD initially adsorbed Hg{sup 0} for about an hour and then catalyzed Hg{sup 0} oxidation to produce Hg{sup 2+}. Apparently, the unburned carbon in ROFA needs to be more rigorously activated in order for it to effectively capture and/or oxidize Hg{sup 0}.
Date:
December 31, 2006
Creator:
Patton, Robert
Object Type:
Text
System:
The UNT Digital Library
Kinetics of Slurry Phase Fischer-Tropsch Synthesis
The overall objective of this project is to develop a comprehensive kinetic model for slurry-phase Fischer-Tropsch synthesis (FTS) employing iron-based catalysts. This model will be validated with experimental data obtained in a stirred-tank slurry reactor (STSR) over a wide range of process conditions. Three STSR tests of the Ruhrchemie LP 33/81 catalyst were conducted to collect data on catalyst activity and selectivity under 25 different sets of process conditions. The observed decrease in 1-olefin content and increase in 2-olefin and n-paraffin contents with the increase in conversion are consistent with a concept that 1-olefins participate in secondary reactions (e.g. 1-olefin hydrogenation, isomerization and readsorption), whereas 2-olefins and n-paraffins are formed in these reactions. Carbon number product distribution showed an increase in chain growth probability with increase in chain length. Vapor-liquid equilibrium calculations were made to check validity of the assumption that the gas and liquid phases are in equilibrium during FTS in the STSR. Calculated vapor phase compositions were in excellent agreement with experimental values from the STSR under reaction conditions. Discrepancies between the calculated and experimental values for the liquid-phase composition (for some of the experimental data) are ascribed to experimental errors in the amount of wax collected from …
Date:
December 31, 2006
Creator:
Bukur, Dragomir B.; Froment, Gilbert F.; Olewski, Tomasz; Nowicki, Lech & Nayapati, Madhav
Object Type:
Report
System:
The UNT Digital Library
Laboratory Directed Research and Development Annual Report to the Department of Energy - December 2005
None
Date:
December 31, 2006
Creator:
Fox, K. J.
Object Type:
Report
System:
The UNT Digital Library
LABORATORY DIRECTED RESEARCH AND DEVELOPMENT ANNUAL REPORT TO THE DEPARTMENT OF ENERGY - DECEMBER 2006
Brookhaven National Laboratory (BNL) is a multidisciplinary laboratory that carries out basic and applied research in the physical, biomedical, and environmental sciences, and in selected energy technologies. It is managed by Brookhaven Science Associates, LLC, (BSA) under contract with the U. S. Department of Energy (DOE). BNL's total annual budget has averaged about $460 million. There are about 2,500 employees, and another 4,500 guest scientists and students who come each year to use the Laboratory's facilities and work with the staff. The BNL Laboratory Directed Research and Development (LDRD) Program reports its status to the U.S. Department of Energy (DOE) annually in March, as required by DOE Order 413.2B, ''Laboratory Directed Research and Development,'' April 19, 2006, and the Roles, Responsibilities, and Guidelines for Laboratory Directed Research and Development at the Department of Energy National Nuclear Security Administration Laboratories dated June 13, 2006. In accordance this is our Annual Report in which we describe the Purpose, Approach, Technical Progress and Results, and Specific Accomplishments of all LDRD projects that received funding during Fiscal Year 2006.
Date:
December 31, 2006
Creator:
Fox, K. J.
Object Type:
Report
System:
The UNT Digital Library
Lignite Fuel Enhancement
None
Date:
December 31, 2006
Creator:
Bullinger, Charles
Object Type:
Report
System:
The UNT Digital Library
Mixed Ionic and Electonic Conductors for Hydrogen Generation and Separation: A New Approach
Composite mixed conductors comprising one electronic conducting phase, and one ionic conducting phase (MIECs) have been developed in this work. Such MIECs have applications in generating and separating hydrogen from hydrocarbon fuels at high process rates and high purities. The ionic conducting phase comprises of rare-earth doped ceria and the electronic conducting phase of rare-earth doped strontium titanate. These compositions are ideally suited for the hydrogen separation application. In the process studied in this project, steam at high temperatures is fed to one side of the MIEC membrane and hydrocarbon fuel or reformed hydrocarbon fuel to the other side of the membrane. Oxygen is transported from the steam side to the fuel side down the electrochemical potential gradient thereby enriching the steam side flow in hydrogen. The remnant water vapor can then be condensed to obtain high purity hydrogen. In this work we have shown that two-phase MIECs comprising rare-earth ceria as the ionic conductor and doped-strontium titanate as the electronic conductor are stable in the operating environment of the MIEC. Further, no adverse reaction products are formed when these phases are in contact at elevated temperatures. The composite MIECs have been characterized using a transient electrical conductivity relaxation technique …
Date:
December 31, 2006
Creator:
Gopalan, Srikanth
Object Type:
Report
System:
The UNT Digital Library
Modeling Brine-Rock Interactions in an Enhanced Geothermal System Deep Fractured Reservoir at Soultz-Sous-Forets (France) - A Joint Approach Using Two Geochemical Codes: Frachem and Toughreact
The modeling of coupled thermal, hydrological, and chemical (THC) processes in geothermal systems is complicated by reservoir conditions such as high temperatures, elevated pressures and sometimes the high salinity of the formation fluid. Coupled THC models have been developed and applied to the study of enhanced geothermal systems (EGS) to forecast the long-term evolution of reservoir properties and to determine how fluid circulation within a fractured reservoir can modify its rock properties. In this study, two simulators, FRACHEM and TOUGHREACT, specifically developed to investigate EGS, were applied to model the same geothermal reservoir and to forecast reservoir evolution using their respective thermodynamic and kinetic input data. First, we report the specifics of each of these two codes regarding the calculation of activity coefficients, equilibrium constants and mineral reaction rates. Comparisons of simulation results are then made for a Soultz-type geothermal fluid (ionic strength {approx}1.8 molal), with a recent (unreleased) version of TOUGHREACT using either an extended Debye-Hueckel or Pitzer model for calculating activity coefficients, and FRACHEM using the Pitzer model as well. Despite somewhat different calculation approaches and methodologies, we observe a reasonably good agreement for most of the investigated factors. Differences in the calculation schemes typically produce less difference …
Date:
December 31, 2006
Creator:
Andre, Laurent; Spycher, Nicolas; Xu, Tianfu; Vuataz, Francois-D. & Pruess, Karsten
Object Type:
Report
System:
The UNT Digital Library
Multifunctional (NOx/CO/O2) Solid-State Sensors For Coal Combustion Control
Solid-state sensors were developed for coal combustion control and the understanding of sensing mechanisms was advanced. Several semiconducting metal oxides (p-type and n-type) were used to fabricate sensor electrodes. The adsorption/desorption characteristics and catalytic activities of these materials were measured with Temperature Programmed Desorption (TPD) and Temperature Programmed Reaction (TPR) experiments. The sensitivity, selectivity, and response time of these sensors were measured for steps of NO, NO{sub 2}, CO, CO{sub 2}, O{sub 2}, and H{sub 2}O vapor in simple N{sub 2}-balanced and multi-component, simulated combustion-exhaust streams. The role of electrode microstructure and fabrication parameters on sensing performance was investigated. Proof for the proposed sensing mechanism, Differential Electrode Equilibria, was demonstrated by relating the sensing behavior (sensitivities and cross-sensitivities) of the various electrode materials to their gas adsorption/desorption behaviors and catalytic activities. A multifunctional sensor array consisting of three sensing electrodes and an integrated heater and temperature sensors was fabricated with tape-casting and screen-printing and its NO{sub x} sensing performance was measured. The multifunctional sensor demonstrated it was possible to measure NO{sub 2} independent of NO by locally heating one of the sensing electrodes. The sensor technology was licensed to Fuel FX International, Inc. Fuel FX has obtained investor funding and …
Date:
December 31, 2006
Creator:
Wachsman, Eric D.
Object Type:
Report
System:
The UNT Digital Library
Novel Binders and Methods for Agglomeration of Ore
Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that will work satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process, and advanced ironmaking processes, where binders must function satisfactorily over an extraordinarily large range of temperatures (from room temperature up to over 1200 C). As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to …
Date:
December 31, 2006
Creator:
Kawatra, S. K.; Eisele, T. C.; Lewandowski, K. A. & Gurtler, J. A.
Object Type:
Report
System:
The UNT Digital Library
NSLS 2006 ACTIVITY REPORT (NATIONAL SYNCHROTRON LIGHT SOURCE ACTIVITY REPORT 2006)
This past year has seen both challenges and fantastic new opportunities for the user community at the NSLS. The fantastic new opportunities are clear and abundant. We now have a five-year strategic plan for new development and continued operation of the NSLS. The NSLS continues to be an extremely productive facility, and the UEC is delighted at how NSLS Chair Chi-Chang Kao has consulted widely within the user community to develop a five-year plan for strategic upgrades and continued operation of the facility. The NSLS-II project, led by Associate Lab Director Steve Dierker, has done very well in its Department of Energy (DOE) reviews and will hopefully soon receive Critical Decision-1 (CD-1) approval, which in DOE lingo gives a go-ahead to launch the detailed design of the facility. We also held the first joint user meeting between the NSLS and Brookhaven's Center for Functional Nanomaterials (CFN), for which the building is near completion. The joint user meeting is an important step toward the close collaboration of the two facilities. The CFN, led by Emilio Mendez, promises to provide capabilities and research foci that are complementary to those at the NSLS. Together, all of these developments give a clear path to …
Date:
December 31, 2006
Creator:
MILLER, L. (EDITOR)
Object Type:
Report
System:
The UNT Digital Library
Office of Rural Community Affairs Biennial Report: 2006
Biennial report of the Office of Rural Community Affairs describing goals, activities, and accomplishments during fiscal year 2006.
Date:
December 31, 2006
Creator:
Office of Rural Community Affairs
Object Type:
Report
System:
The Portal to Texas History
Optical Fiber Chemical Sensor with Sol-Gel Derived Refractive Material as Transducer for High Temperature Gas Sensing in Clean Coal Technology
The chemistry of sol-gel derived silica and refractive metal oxide has been systematically studied. Sol-gel processes have been developed for preparing porous silica and semiconductor metal oxide materials. Micelle/reversed micelle techniques have been developed for preparing nanometer sized semiconductor metal oxides and noble metal particles. Techniques for doping metal ions, metal oxides and nanosized metal particles into porous sol-gel material have also been developed. Optical properties of sol-gel derived materials in ambient and high temperature gases have been studied by using fiber optic spectroscopic techniques, such as fiber optic ultraviolet/visible absorption spectrometry, fiber optic near infrared absorption spectrometry and fiber optic fluorescence spectrometry. Fiber optic spectrometric techniques have been developed for investigating the optical properties of these sol-gel derived materials prepared as porous optical fibers or as coatings on the surface of silica optical fibers. Optical and electron microscopic techniques have been used to observe the microstructure, such as pore size, pore shape, sensing agent distribution, of sol-gel derived material, as well as the size and morphology of nanometer metal particle doped in sol-gel derived porous silica, the nature of coating of sol-gel derived materials on silica optical fiber surface. In addition, the chemical reactions of metal ion, nanostructured semiconductor …
Date:
December 31, 2006
Creator:
Tao, Shiquan
Object Type:
Report
System:
The UNT Digital Library
Oxygen Transport Ceramic Membranes
Ti doping on La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} (LSF) tends to increase the oxygen equilibration kinetics of LSF in lower oxygen activity environment because of the high valence state of Ti. However, the addition of Ti decreases the total conductivity because the acceptor ([Sr{prime}{sub La}]) is compensated by the donor ([Ti{sub Fe}{sup {sm_bullet}}]) which decreases the carrier concentration. The properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 1-x}Ti{sub x}O{sub 3-{delta}} (LSFT, x = 0.45) have been experimentally and theoretically investigated to elucidate (1) the dependence of oxygen occupancy and electrochemical properties on temperature and oxygen activity by thermogravimetric analysis (TGA) and (2) the electrical conductivity and carrier concentration by Seebeck coefficient and electrical measurements. In the present study, dual phase (La{sub 0.2}Sr{sub 0.8}Fe{sub 0.6}Ti{sub 0.4}O{sub 3-{delta}}/Ce{sub 0.9}Gd{sub 0.1}O{sub 2-{delta}}) membranes have been evaluated for structural properties such as hardness, fracture toughness and flexural strength. The effect of high temperature and slightly reducing atmosphere on the structural properties of the membranes was studied. The flexural strength of the membrane decreases upon exposure to slightly reducing conditions at 1000 C. The as-received and post-fractured membranes were characterized using XRD, SEM and TG-DTA to understand the fracture mechanisms. Changes in structural properties of the composite were sought …
Date:
December 31, 2006
Creator:
Bandopadhyay, S. & Nithyanantham, T.
Object Type:
Report
System:
The UNT Digital Library
The Panola Watchman (Carthage, Tex.), Vol. 134, No. 103, Ed. 1 Sunday, December 31, 2006
Semiweekly newspaper from Carthage, Texas that includes local, state, and national news along with advertising.
Date:
December 31, 2006
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Phase II Calderon Process to Produce Direct Reduced Iron Research and Development Project
None
Date:
December 31, 2006
Creator:
Calderon, Albert
Object Type:
Report
System:
The UNT Digital Library
Polk County Enterprise (Livingston, Tex.), Vol. 124, No. 105, Ed. 1 Sunday, December 31, 2006
Semi-weekly newspaper from Livingston, Texas that includes local, state and national news along with advertising.
Date:
December 31, 2006
Creator:
White, Barbara
Object Type:
Newspaper
System:
The Portal to Texas History
Quantum Well Thermoelectrics for Converting Waste Heat to Electricity
None
Date:
December 31, 2006
Creator:
Ghamaty, Saeid
Object Type:
Report
System:
The UNT Digital Library
Radkowsky Thorium Fuel Project
In the early/mid 1990’s Prof. Alvin Radkowsky, former chief scientist of the U.S. Naval Reactors program, proposed an alternate fuel concept employing thorium-based fuel for use in existing/next generation pressurized water reactors (PWRs). The concept was based on the use of a 'seed-blanket-unit' (SBU) that was a one-for-one replacement for a standard PWR assembly with a uranium-based central 'driver' zone, surrounded by a 'blanket' zone containing uranium and thorium. Therefore, the SBU could be retrofit without significant modifications into existing/next generation PWRs. The objective was to improve the proliferation and waste characteristics of the current once-through fuel cycle. The objective of a series of projects funded by the Initiatives for Proliferation Prevention program of the U.S. Department of Energy (DOE-IPP) - BNL-T2-0074,a,b-RU 'Radkowsky Thorium Fuel (RTF) Concept' - was to explore the characteristics and potential of this concept. The work was performed under several BNL CRADAs (BNL-C-96-02 and BNL-C-98-15) with the Radkowsky Thorium Power Corp./Thorium Power Inc. and utilized the technical and experimental capabilities in the Former Soviet Union (FSU) to explore the potential of this concept for implementation in Russian pressurized water reactors (VVERs), and where possible, also generate data that could be used for design and licensing of …
Date:
December 31, 2006
Creator:
Todosow, Michael
Object Type:
Report
System:
The UNT Digital Library
Reducing Ultra-Clean Transportation Fuel Costs with HyMelt Hydrogen
None
Date:
December 31, 2006
Creator:
Malone, Donald P. & Renner, William R.
Object Type:
Report
System:
The UNT Digital Library
Reliable, Economic, Efficient CO2 Heat Pump Water Heater for North America
Adoption of heat pump water heating technology for commercial hot water could save up to 0.4 quads of energy and 5 million metric tons of CO2 production annually in North America, but industry perception is that this technology does not offer adequate performance or reliability and comes at too high of a cost. Development and demonstration of a CO2 heat pump water heater is proposed to reduce these barriers to adoption. Three major themes are addressed: market analysis to understand barriers to adoption, use of advanced reliability models to design optimum qualification test plans, and field testing of two phases of water heater prototypes. Market experts claim that beyond good performance, market adoption requires 'drop and forget' system reliability and a six month payback of first costs. Performance, reliability and cost targets are determined and reliability models are developed to evaluate the minimum testing required to meet reliability targets. Three phase 1 prototypes are designed and installed in the field. Based on results from these trials a product specification is developed and a second phase of five field trial units are built and installed. These eight units accumulate 11 unit-years of service including 15,650 hours and 25,242 cycles of compressor …
Date:
December 31, 2006
Creator:
Radcliff, Thomas D; Sienel, Tobias; Huff, Hans-Joachim; Thompson, Adrian; Sadegh, Payman; Olsommer, Benoit et al.
Object Type:
Report
System:
The UNT Digital Library