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3-D Seismic Experimentation and Advanced Processing/Inversion Development for Investigations of the Shallow Subsurface (open access)

3-D Seismic Experimentation and Advanced Processing/Inversion Development for Investigations of the Shallow Subsurface

Gian Fradelizio, a Rice Ph.D. student has completed reprocessing the 3D seismic reflection data acquired at Hill AFB through post-stack depth migration for comparison to the traveltime and waveform tomography results. Zelt, Levander, Fradelizio, and 5 others spent a week at Hill AFB in September 2005, acquiring an elastic wave data set along 2 profiles. We used 60 3-component Galperin mounted 40 Hz geophones recorded by 3 GEOMETRICS Stratavision systems. The seismic source employed was a sledgehammer used to generate transverse, and radial, and vertical point source data. Data processing has begun at Rice to generate S-wave reflection and refraction images. We also acquired surface wave and ground penetrating rada data to complement the elastic wave dataset.
Date: June 1, 2005
Creator: Levander, Alan R.
System: The UNT Digital Library
2005 Habitat Evaluation Procedure (HEP) Report for the Carey Creek Project (open access)

2005 Habitat Evaluation Procedure (HEP) Report for the Carey Creek Project

In August 2002, the Habitat Evaluation Procedure (HEP) was used to determine baseline habitat suitability on the Carey Creek property, an acquisition completed by the Kalispel Tribe of Indians in December 2001. Evaluation species and appropriate models include bald eagle, black-capped chickadee, Canada goose, mallard, yellow warbler, and white-tailed deer. Habitat Suitability Index (HSI) values were visually estimated and agreed upon by all HEP team members. The Carey Creek Project provides a total of 172.95 Habitat Units (HUs) for the species evaluated. Conifer forest habitat provides 4.91 HUs for bald eagle, black-capped chickadee, and white-tailed deer. Forested wetlands provide 52.68 HUs for bald eagle, black-capped chickadee, mallard, and white-tailed deer. Scrub-shrub wetlands provide 2.82 HUs for mallard, yellow warbler and white-tailed deer. Wet meadow and grassland meadow provide 98.13 HUs for mallard and Canada goose. Emergent wetlands provide 11.53 HUs for mallard, muskrat, and Canada goose. Open water provides 2.88 HUs for Canada goose, mallard, and muskrat. The objective of using HEP at the Carey Creek Project and other protected properties is to document the quality and quantity of available habitat for selected wildlife species. In this way, HEP provides information on the relative value of the same area at …
Date: June 2005
Creator: Entz, Ray
System: The UNT Digital Library
Acoustic Monitor for Liquid-Solid Slurries Measurements at Low Weight Fractions (open access)

Acoustic Monitor for Liquid-Solid Slurries Measurements at Low Weight Fractions

Our effort in this project is to develop an acoustic monitor for accurate, real-time characterization of the size and weight fractions of solids in slurries for process monitoring and to determine the optimal timing for slurry transfers. This capability will be valuable in the Savannah River Site accelerated clean-up program. Our scientific work during the first research period developed a theory, supported by experiments, to describe sound attenuation of solids in suspensions in the presence of bubbles, which permits us to determine the solid-liquid weight percent. Engineering developments during the second research period led to the design, construction, and demonstration, in our laboratories, of the Syracuse Acoustic Monitor (SAM) system that measures weight percent solids accurately in slurries of 0.5 to 8.0 weight percent on-line and in real-time. Also, we had shown the potential for these measurements in solid-gas-liquid slurries by removing the interference due to the presence of gas bubbles.
Date: June 1, 2005
Creator: Tavlarides, Lawrence L.
System: The UNT Digital Library
Acoustic Monitor for Liquid-Solid Slurries Measurements at Low Weight Fractions (open access)

Acoustic Monitor for Liquid-Solid Slurries Measurements at Low Weight Fractions

Our effort in this project is to develop an acoustic monitor for accurate, real-time characterization of the size and weight fractions of solids in slurries for process monitoring and to determine the optimal timing for slurry transfers. This capability will be valuable in the Savannah River Site accelerated clean-up program. Our scientific work during the first research period developed a theory, supported by experiments, to describe sound attenuation of solids in suspensions in the presence of bubbles, which permits us to determine the solid-liquid weight percent. Engineering developments during the second research period led to the design, construction, and demonstration, in our laboratories, of the Syracuse Acoustic Monitor (SAM) system that measures weight percent solids accurately in slurries of 0.5 to 8.0 weight percent on-line and in real-time. Also, we had shown the potential for these measurements in solid-gas-liquid slurries by removing the interference due to the presence of gas bubbles.
Date: June 1, 2005
Creator: Taviarides, Lawrence L.
System: The UNT Digital Library
Active Sonar and Marine Mammals: Chronology with References (open access)

Active Sonar and Marine Mammals: Chronology with References

The deployment of active sonar by the U.S. Navy and its potential impacts on marine mammals has been an ongoing issue of intense debate; regulatory, legislative, and judicial activity; and international concern. This report provides a chronology of significant events and documents since 1994.
Date: June 1, 2005
Creator: Calvert, Kori & Buck, Eugene H.
System: The UNT Digital Library
Advanced Design of a Novel Stellarator Using the Free Boundary VMEC Magnetic Equilibrium Code. Final Technical Report for period March 1, 1999 - February 28, 2002 (open access)

Advanced Design of a Novel Stellarator Using the Free Boundary VMEC Magnetic Equilibrium Code. Final Technical Report for period March 1, 1999 - February 28, 2002

This report describes the goals and accomplishments of a 3-year EPSCoR Laboratory Partnership award to design an advanced stellarator device for magnetic confinement of toroidal plasmas for fusion research.
Date: June 1, 2005
Creator: Knowlton, S. F.
System: The UNT Digital Library
Advanced Gamma-Ray Detection Concepts Combined with Real-Time Compton Suppression for Nondestructive, Gamma-Ray Characterization of Remote Handled Waste (open access)

Advanced Gamma-Ray Detection Concepts Combined with Real-Time Compton Suppression for Nondestructive, Gamma-Ray Characterization of Remote Handled Waste

Nondestructive gamma ray characterization of remote-handled waste is significantly complicated by the presence of Compton scattering in the detector and waste matrix produced by intense cesium gamma rays. This research seeks to understand the photophysics of a new type of inorganic scintillation gamma ray detector, optimize the combination of this gamma ray detector with a Compton guard detector, develop new Monte Carlo solution algorithms for modeling Compton scattering in the waste, and to model the real time intensity of cesium produced Compton scattering. A successful research program will provide the fundamental information needed to design and develop advanced Compton spectrometers for assay of remote handled waste and new higher sensitivity spectrometers for environmental measurements.
Date: June 1, 2005
Creator: Mcllwain, Michael E.; Haghighat, Alireza; Dorenbos, Pieter & Hartwell, John K.
System: The UNT Digital Library
Advanced Multi-Product Coal Utilization By-Product Processing Plant (open access)

Advanced Multi-Product Coal Utilization By-Product Processing Plant

The objective of the project is to build a multi-product ash beneficiation plant at Kentucky Utilities 2,200-MW Ghent Generating Station, located in Carroll County, Kentucky. This part of the study includes the examination of the feedstocks for the beneficiation plant. The ash, as produced by the plant, and that stored in the lower pond were examined. Filter media candidates were evaluated for dewatering the ultrafine ash (UFA) product. Media candidates were selected based on manufacturer recommendations and evaluated using standard batch filtration techniques. A final media was selected; 901F, a multifilament polypropylene. While this media would provide adequate solids capture and cake moisture, the use of flocculants would be necessary to enable adequate filter throughput. Several flocculant chemistries were also evaluated and it was determined that polyethylene oxide (PEO) at a dosage of 5 ppm (slurry basis) would be the most suitable in terms of both settling rate and clarity. PEO was evaluated on a continuous vacuum filter using 901F media. The optimum cycle time was found to be 1.25 minutes which provided a 305% moisture cake, 85% solids capture with a throughput of 115 lbs dry solids per hour and a dry cake rate of 25 lb/ft2/hr. Increasing cycle …
Date: June 1, 2005
Creator: Groppo, John & Robl, Thomas
System: The UNT Digital Library
AECL/US INERI - Development of Inert Matrix Fuels for Plutonium and Minor Actinide Management in Power Reactors -- Fuel Requirements and Down-Select Report (open access)

AECL/US INERI - Development of Inert Matrix Fuels for Plutonium and Minor Actinide Management in Power Reactors -- Fuel Requirements and Down-Select Report

The U.S. Advanced Fuel Cycle Program and the Atomic Energy Canada Ltd (AECL) seek to develop and demonstrate the technologies needed to minimize the overall Pu and minor actinides present in the light water reactor (LWR) nuclear fuel cycles. It is proposed to reuse the Pu from LWR spent fuel both for the energy it contains and to decrease the hazard and proliferation impact resulting from storage of the Pu and minor actinides. The use of fuel compositions with a combination of U and Pu oxide (MOX) has been proposed as a way to recycle Pu and/or minor actinides in LWRs. It has also been proposed to replace the fertile U{sup 238} matrix of MOX with a fertile-free matrix (IMF) to reduce the production of Pu{sup 239} in the fuel system. It is important to demonstrate the performance of these fuels with the appropriate mixture of isotopes and determine what impact there might be from trace elements or contaminants. Previous work has already been done to look at weapons-grade (WG) Pu in the MOX configuration [1][2] and the reactor-grade (RG) Pu in a MOX configuration including small (4000 ppm additions of Neptunium). This program will add to the existing database …
Date: June 1, 2005
Creator: Carmack, William; Lee, Randy D.; Medvedev, Pavel; Meyer, Mitch; Todosow, Michael; Hamilton, Holly B. et al.
System: The UNT Digital Library
Anaerobic Biotransformation and Mobility of Pu and PuEDTA (open access)

Anaerobic Biotransformation and Mobility of Pu and PuEDTA

Although our goal is to isolate anaerobic EDTA degraders, we initiated the experiments to include nitrilotriacetate (NTA), which is a structure homologue of EDTA. All the aerobic EDTA degraders can degrade NTA, but the isolated NTA degraders cannot degrade EDTA. Since NTA is a simpler structure homologue, it is likely that EDTA-degrading ability is evolved from NTA degradation. This hypothesis is further supported from our characterization of EDTA and NTA-degrading enzymes and genes (J. Bact. 179:1112-1116; and Appl. Environ. Microbiol. 67:688-695). The EDTA monooxygenase and NTA monooxygenase are highly homologous. EDTA monooxygenase can use both EDTA and NTA as substrates, but NTA monooxygenase can only use NTA as a substrate. Thus, we put our effort to isolate both NTA and EDTA degraders. In case, an anaerobic EDTA degrader is not immediately enriched, we will try to evolve the NTA degraders to use EDTA. Both aerobic and anaerobic enrichment cultures were set.
Date: June 1, 2005
Creator: Xun, Luying
System: The UNT Digital Library
Anaerobic Biotransformation and Mobility of Pu and PuEDTA (open access)

Anaerobic Biotransformation and Mobility of Pu and PuEDTA

The objective of this report is to isolate anaerobic EDTA-degrading bacteria. Although our goal is to isolate anaerobic EDTA degraders, we initiated the experiments to include nitrilotriacetate (NTA), which is a structure homologue of EDTA. All the aerobic EDTA degraders can degrade NTA, but the isolated NTA degraders cannot degrade EDTA. Since NTA is a simpler structure homologue, it is likely that EDTA-degrading ability is evolved from NTA degradation. This hypothesis is further supported from our characterization of EDTA and NTA-degrading enzymes and genes (J. Bact. 179:1112-1116; and Appl. Environ. Microbiol. 67:688-695). The EDTA monooxygenase and NTA monooxygenase are highly homologous. EDTA monooxygenase can use both EDTA and NTA as substrates, but NTA monooxygenase can only use NTA as a substrate. Thus, we put our effort to isolate both NTA and EDTA degraders. In case, an anaerobic EDTA degrader is not immediately enriched, we will try to evolve the NTA degraders to use EDTA. Both aerobic and anaerobic enrichment cultures were set.
Date: June 1, 2005
Creator: Xun, Luying
System: The UNT Digital Library
Anaerobic U(IV) Bio-oxidation and the Resultant Remobilization of Uranium in Contaminated Sediments (open access)

Anaerobic U(IV) Bio-oxidation and the Resultant Remobilization of Uranium in Contaminated Sediments

A proposed strategy for the remediation of uranium (U) contaminated sites is based on immobilizing U by reducing the oxidized soluble U, U(VI), to form a reduced insoluble end product, U(IV). Due to the use of nitric acid in the processing of nuclear fuels, nitrate is often a co-contaminant found in many of the environments contaminated with uranium. Recent studies indicate that nitrate inhibits U(VI) reduction in sediment slurries. However, the mechanism responsible for the apparent inhibition of U(VI) reduction is unknown, i.e. preferential utilization of nitrate as an electron acceptor, direct biological oxidation of U(IV) coupled to nitrate reduction, and/or abiotic oxidation by intermediates of nitrate reduction. Recent studies indicates that direct biological oxidation of U(IV) coupled to nitrate reduction may exist in situ, however, to date no organisms have been identified that can grow by this metabolism. In an effort to evaluate the potential for nitrate-dependent bio-oxidation of U(IV) in anaerobic sedimentary environments, we have initiated the enumeration of nitrate-dependent U(IV) oxidizing bacteria. Sediments, soils, and groundwater from uranium (U) contaminated sites, including subsurface sediments from the NABIR Field Research Center (FRC), as well as uncontaminated sites, including subsurface sediments from the NABIR FRC and Longhorn Army Ammunition …
Date: June 1, 2005
Creator: Coates, John D.
System: The UNT Digital Library
Analysis Methods and Desired Outcomes of the Analysis of Intermediate and Process Heat Exchanger Loop Requirements (open access)

Analysis Methods and Desired Outcomes of the Analysis of Intermediate and Process Heat Exchanger Loop Requirements

The components of the intermediate heat transfer loop will be subjected to conditions that may produce time dependent deformation, corrosion and erosion. High temperature strength may also be an issue with many components. A stress analysis will be performed on the intermediate heat exchanger of the PCHE type and the implications on material requirements will be determined. Potential materials of construction will be identified and evaluated in light of the stress analysis and the available creep data. A concentric or annular pipe design for carrying both the hot and cold fluid streams in the intermediate loop will be modeled to determine the temperature drop between the NGNP and the hydrogen production facility. This design will be compared to separate piping for the hot and cold fluid streams. Finally two designs for the process heat exchangers will be evaluated for catalytic and thermal effectiveness. All the evaluations mentioned above will be performed for both high pressure helium and liquid salt as the heat transport media. Also, materials and materials issue swill be discussed with regard to the evaluations.
Date: June 1, 2005
Creator: Lillo, T.M.
System: The UNT Digital Library
Analysis of Hydraulic Responses from the ER-6-1 Multiple-Well Aquifer Test, Yucca Flat FY 2004 Testing Program, Nevada Test Site, Nye County, Nevada, Rev. No.: 0 (open access)

Analysis of Hydraulic Responses from the ER-6-1 Multiple-Well Aquifer Test, Yucca Flat FY 2004 Testing Program, Nevada Test Site, Nye County, Nevada, Rev. No.: 0

This report documents the interpretation and analysis of the hydraulic data collected for the Fiscal Year (FY) 2004 Multiple-Well Aquifer Test-Tracer Test (MWAT-TT) conducted at the ER-6-1 Well Cluster in Yucca Flat Corrective Action Unit (CAU) 97, on the Nevada Test Site (NTS). The MWAT-TT was performed to investigate CAU-scale groundwater flow and transport processes related to the transport of radionuclides from sources on the NTS through the Lower Carbonate Aquifer (LCA) Hydrostratigraphic Unit (HSU). The ER-6-1 MWAT-TT was planned and executed by contractor participants for the Underground Test Area (UGTA) Project of the Environmental Restoration (ER) program of the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO). Participants included Stoller-Navarro Joint Venture (SNJV), the Environmental Engineering Services Contractor; Bechtel Nevada (BN); the Desert Research Institute (DRI); Los Alamos National Laboratory; and the University of Nevada, Las Vegas-Harry Reid Center. The SNJV team consists of the S.M. Stoller Corporation, Navarro Research and Engineering, Battelle Memorial Institute, INTERA Inc., and Weston Solutions, Inc. The MWAT-TT was implemented according to the ''Underground Test Area Project, ER-6-1 Multi-Well Aquifer Test - Tracer Test Plan'' (SNJV, 2004a) issued in April 2004. The objective of the aquifer test was to …
Date: June 1, 2005
Creator: Ruskauff, Greg
System: The UNT Digital Library
Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Tasks for October 1, 2003 through September 30, 2004 (open access)

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Tasks for October 1, 2003 through September 30, 2004

The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2004. Production and production maintenance activities for flight quality (FQ) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. In all three cases, production maintenance is assured by the manufacture of limited quantities of FQ components. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.
Date: June 1, 2005
Creator: unknown
System: The UNT Digital Library
The Aqueous Thermodynamics and Complexation Reactions of Anionic Silica and Uranium Species to High Concentration. (open access)

The Aqueous Thermodynamics and Complexation Reactions of Anionic Silica and Uranium Species to High Concentration.

Highly basic tank wastes contain several important radionuclides, including 90Sr, 99Tc, and 60Co, as well as actinide elements (i.e., isotopes of U, Pu, and Am). These highly basic tank wastes are known to have leaked into the vadose zone at the Hanford Site. In particular, wastes from the bismuth phosphate process contained very high concentrations of U as well as carbonate, phosphate, nitrate, and other components (AEC 1951) and these solutions have leaked into the subsurface at the Hanford site. The tanks containing the bismuth phosphate wastes were frequently saturated with respect to the solid phases of these components [e.g., NaUO2PO4(c) and Na4UO2(CO3)3(c)]. These solids were referred to as ''hard sludge'' (Na4UO2(CO3)3(c)) and ?soft sludge? [NaUO2PO4(c)] because of their different crystal forms. The preliminary studies of the solubility of these solids in tank wastes (AEC 1951) indicate that aqueous U carbonate complexes dominate the solution chemistry of uranium even when the equilibrium solid was NaUO2PO4. Thus there was a need to develop an accurate thermodynamic model for the solubility of potentially important U(VI) phosphate and carbonate phases as well as to develop a model for the uranium carbonate complexes valid to high ionic strength. In this project we are examining …
Date: June 1, 2005
Creator: Felmy, Andrew R. & Choppin, Gregory R.
System: The UNT Digital Library
Aspects of the Louisiana Coastal Current (open access)

Aspects of the Louisiana Coastal Current

This report is about the status of existing reduced dimensional models of the dynamics of the Louisiana Coastal Current. Local, wind-driven models reproduce credibly the flow variability during the winter season.
Date: June 2005
Creator: United States. Coastal Marine Institute.
System: The UNT Digital Library
Attack Methodology Analysis: Emerging Trends in Computer-Based Attack Methodologies and Their Applicability to Control System Networks (open access)

Attack Methodology Analysis: Emerging Trends in Computer-Based Attack Methodologies and Their Applicability to Control System Networks

Threat characterization is a key component in evaluating the threat faced by control systems. Without a thorough understanding of the threat faced by critical infrastructure networks, adequate resources cannot be allocated or directed effectively to the defense of these systems. Traditional methods of threat analysis focus on identifying the capabilities and motivations of a specific attacker, assessing the value the adversary would place on targeted systems, and deploying defenses according to the threat posed by the potential adversary. Too many effective exploits and tools exist and are easily accessible to anyone with access to an Internet connection, minimal technical skills, and a significantly reduced motivational threshold to be able to narrow the field of potential adversaries effectively. Understanding how hackers evaluate new IT security research and incorporate significant new ideas into their own tools provides a means of anticipating how IT systems are most likely to be attacked in the future. This research, Attack Methodology Analysis (AMA), could supply pertinent information on how to detect and stop new types of attacks. Since the exploit methodologies and attack vectors developed in the general Information Technology (IT) arena can be converted for use against control system environments, assessing areas in which cutting …
Date: June 1, 2005
Creator: Rolston, Bri
System: The UNT Digital Library
An Audit Report on the Railroad Commission's Oil and Gas Migration Project (open access)

An Audit Report on the Railroad Commission's Oil and Gas Migration Project

Report of the Texas State Auditor's Office related to determining whether controls for the Railroad Commission's (Commission) Oil and Gas Migration Project are adequate to ensure that the project will be delivered on schedule, on budget, and with the desired level of user functionality upon implementation, including whether delivery of the agreed-upon functionality is supported by procurement documentation; project management has adequate and complete project planning documents, an adequate plan to address potential risks, and an adequate process to manage changes to the project; the administration of contracted services ensures appropriate use of state funds; and the actual costs incurred and projected cost estimates are adequately supported.
Date: June 2005
Creator: Texas. Office of the State Auditor.
System: The Portal to Texas History
Balancing of Pulverized Coal Flows to Burners in Boilers With Pressurized Vertical Spindle Mills (open access)

Balancing of Pulverized Coal Flows to Burners in Boilers With Pressurized Vertical Spindle Mills

Numerical modeling of a vertical spindle mill was performed using commercially available CFD software, Fluent 6.1. The results of an experimental study that had been carried out for a Stairmand cyclone were used for model development and verification since both the vertical spindle pulverizer and the cyclone have strong swirling flow and particle separation within the geometry.
Date: June 1, 2005
Creator: Bilirgen, Harun
System: The UNT Digital Library
Benchmarking survey for recycling. (open access)

Benchmarking survey for recycling.

This report describes the methodology, analysis and conclusions of a comparison survey of recycling programs at ten Department of Energy sites including Sandia National Laboratories/New Mexico (SNL/NM). The goal of the survey was to compare SNL/NM's recycling performance with that of other federal facilities, and to identify activities and programs that could be implemented at SNL/NM to improve recycling performance.
Date: June 1, 2005
Creator: Marley, Margie Charlotte & Mizner, Jack Harry
System: The UNT Digital Library
Biogeochemical Cycling and Environmental Stability of Pu Relevant to Long-Term Stewardship of DOE Sites (open access)

Biogeochemical Cycling and Environmental Stability of Pu Relevant to Long-Term Stewardship of DOE Sites

The overall objective of this proposed research is to understand the biogeochemical cycling of Pu in environments of interest to long-term DOE stewardship issues. Central to Pu cycling (transport initiation to immobilization) is the role of microorganisms. The hypothesis underlying this proposal is that microbial activity is the causative agent in initiating the mobilization of Pu in near-surface environments: through the transformation of Pu associated with solid phases, production of extracellular polymeric substances (EPS) carrier phases, and the creation of microenvironments. Also, microbial processes are central to the immobilization of Pu species, through the metabolism of organically complexed Pu species and Pu associated with extracellular carrier phases and the creation of environments favorable for Pu transport retardation.
Date: June 1, 2005
Creator: Francis, Arokiasamy J.; Santschi, Peter H. & Honeyman, Bruce D.
System: The UNT Digital Library
Biotransformation involved in sustained reductive removal of uranium in contaminant aquifers (open access)

Biotransformation involved in sustained reductive removal of uranium in contaminant aquifers

This report summarizes progress made from August 2004 to July 2005. During this period research focused primarily on obtaining a better understanding of the factors controlling the reduction of U(VI) during in situ uranium bioremediation as well as investigating the potential for using electrodes as an alternative electron donor to promote in situ uranium reduction. Analysis of the 2003 experiment at the field study site in Rifle, CO was completed. The results demonstrated the substantial heterogeneity of the zone undergoing bioremediation, both in terms of geochemistry and microbiology. The lack of U(VI) reduction under sulfate-reducing conditions was clearly documented. The need for more detailed sampling both with time and with depth in the aquifer was demonstrated. For the first time a comparison between the composition of the microbial community in the sediments and the microbes in the corresponding groundwater was attempted. The findings from this study are important not only in further demonstrating the potential for in situ uranium bioremediation, but also for indicating how methods and sampling approaches should be improved in the future. A manuscript summarizing these findings has been accepted for publication in Applied and Environmental Microbiology. In summer of 2004 a new field experiment was conducted …
Date: June 1, 2005
Creator: Lovley, Derek R.
System: The UNT Digital Library
Ceramic Membrane Enabling Technology for Improved IGCC Efficiency (open access)

Ceramic Membrane Enabling Technology for Improved IGCC Efficiency

This final report summarizes work accomplished in the program from October 1, 1999 through December 31,2004. While many of the key technical objectives for this program were achieved, after a thorough economic and OTM (Oxygen Transport Membrane) reliability analysis were completed, a decision was made to terminate the project prior to construction of a second pilot reactor. In the program, oxygen with purity greater than 99% was produced in both single tube tests and multi-tube pilot plant tests for over 1000 hours. This demonstrated the technical viability of using ceramic OTM devices for producing oxygen from a high pressure air stream. The oxygen fluxes that were achieved in single tube tests exceeded the original target flux for commercial operation. However, extended testing showed that the mean time to failure of the ceramics was insufficient to enable a commercially viable system. In addition, manufacturing and material strength constraints led to size limitations of the OTM tubes that could be tested. This has a severe impact on the cost of both the ceramic devices, but also the cost of assembling the OTM tubes in a large reactor. As such and combined with significant progress in cost reduction of large cryogenic oxygen separation …
Date: June 1, 2005
Creator: Sirman, John & vanHassel, Bart
System: The UNT Digital Library