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A process model of natural attenuation in drainage from a historic mining district (open access)

A process model of natural attenuation in drainage from a historic mining district

A process model was used to better understand the controls on the chemical evolution of drainage in a historic mining district. At the Pecos Mine Operable Unit, New Mexico, drainage near the waste rock pile is acidic (pH varies from 3.0--5.0) and carries high concentrations of Zn, Al, Cu and Pb. As drainage flows toward the Pecos River, pH increases to greater than 7 and heavy metal content decreases. A process model of natural attenuation in this drainage shows the main controls on pH are reaction with a local bedrock that contains limestone, and concurrent mixing with tributary streams. Models that account for both calcite dissolution and mixing reproduce the observed decrease in aqueous metal concentrations with increasing pH. Contaminant concentrations attenuate primarily via two distinct pathways: Al, Cu, Fe and Pb precipitate directly from solution, whereas Zn, Mg, Mn and SO{sub 4} concentrations decrease primarily through dilution. Additionally, Pb adsorbs to precipitating hydroxide surfaces.
Date: June 5, 2000
Creator: BERGER,AMY C.; BETHKE,CRAIG M. & KRUMHANSL,JAMES L.
Object Type: Article
System: The UNT Digital Library
Perry Daily Journal (Perry, Okla.), Vol. 107, No. 110, Ed. 1 Monday, June 5, 2000 (open access)

Perry Daily Journal (Perry, Okla.), Vol. 107, No. 110, Ed. 1 Monday, June 5, 2000

Daily newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising.
Date: June 5, 2000
Creator: Brown, Gloria
Object Type: Newspaper
System: The Gateway to Oklahoma History
Relative x-ray backlighter intensity comparison of ti and ti/sc combination foils driven in double-sided and single-sided laser configuration (open access)

Relative x-ray backlighter intensity comparison of ti and ti/sc combination foils driven in double-sided and single-sided laser configuration

Use of multiple backlighter foils and/or double-sided laser interaction geometry with backlit imaging can result in improved backlighter efficiency. An experimental comparison of backlighter intensity for Ti foils and Ti/Sc combination foils in both the one-sided and double-sided laser-interaction configuration is presented. Spectrally-integrated framing camera images show intensity contributions of front and rear backlighter surfaces for both foil types. Analysis of time-resolved x-ray spectra collected from foil targets show the relative contribution of Ti and Sc 2-1 He-like resonance lines to the total backlighter intensity.
Date: June 5, 2000
Creator: Bullock, A. B.; Landen, O. L. & Bradley, D. K.
Object Type: Article
System: The UNT Digital Library
The Express-Star (Chickasha, Okla.), Ed. 1 Monday, June 5, 2000 (open access)

The Express-Star (Chickasha, Okla.), Ed. 1 Monday, June 5, 2000

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date: June 5, 2000
Creator: Bush, Kent
Object Type: Newspaper
System: The Gateway to Oklahoma History
Altus Times (Altus, Okla.), Vol. 101, No. 71, Ed. 1 Monday, June 5, 2000 (open access)

Altus Times (Altus, Okla.), Vol. 101, No. 71, Ed. 1 Monday, June 5, 2000

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: June 5, 2000
Creator: Bush, Michael
Object Type: Newspaper
System: The Gateway to Oklahoma History
The Baytown Sun (Baytown, Tex.), Vol. 78, No. 192, Ed. 1 Monday, June 5, 2000 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 78, No. 192, Ed. 1 Monday, June 5, 2000

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: June 5, 2000
Creator: Cash, Wanda Garner
Object Type: Newspaper
System: The Portal to Texas History
Room Temperature Continuous Wave InGaSsN Quantum Well Vertical Cavity Lasers Emitting at 1.3 um (open access)

Room Temperature Continuous Wave InGaSsN Quantum Well Vertical Cavity Lasers Emitting at 1.3 um

Selectively oxidized vertical cavity lasers emitting at 1294 nm using InGaAsN quantum wells are reported for the first time which operate continuous wave at and above room temperature. The lasers employ two n-type Al{sub 0.94}Ga{sub 0.06}As/GaAs distributed Bragg reflectors each with a selectively oxidized current aperture adjacent to the optical cavity, and the top output mirror contains a tunnel junction to inject holes into the active region. Continuous wave single mode lasing is observed up to 55 C. These lasers exhibit the longest wavelength reported to date for vertical cavity surface emitting lasers grown on GaAs substrates.
Date: June 5, 2000
Creator: Choquette, Kent D.; Klem, John F.; Fischer, Arthur J.; Spahn, Olga B.; Allerman, Andrew A.; Fritz, Ian J. et al.
Object Type: Article
System: The UNT Digital Library
A Study of the Effects of Disorder in the 2D Hubbard Model (open access)

A Study of the Effects of Disorder in the 2D Hubbard Model

We study the effects of disorder on long range antiferromagnetic correlations and the Mott gap in the half-filled, two dimensional, repulsive Hubbard model. We employ Hartree-Fock (HF) and Quantum Monte Carlo (QMC) techniques in our study of the bond and site disordered models. Results from mean field (HF) calculations are used to develop a qualitative picture of the physics and to guide our choice for input to the QMC methods. The basic properties of two QMC methods for correlated fermions are discussed, and the results from these different approaches are presented.
Date: June 5, 2000
Creator: Enjalran, M.; Hebert, F.; Scalettar, R.; Zhang, S. & Batrouni, G.
Object Type: Article
System: The UNT Digital Library
From science to compliance: Geomechanics studies of the Waste Isolation Pilot Plant (open access)

From science to compliance: Geomechanics studies of the Waste Isolation Pilot Plant

Mechanical and hydrological properties of salt provide excellent bases for geological isolation of hazardous materials. Regulatory certification of the Waste Isolation Pilot Plant (WIPP) testifies to the nearly ideal characteristics of bedded salt deposits in southeast New Mexico. The WIPP history includes decades of testing and scientific investigations, which have resulted in a comprehensive understanding of salt's mechanical deformational and hydrological properties over an applicable range of stresses and temperatures. Comprehensive evaluation of salt's favorable characteristics helped demonstrate regulatory compliance and ensure isolation of radioactive waste placed in a salt geological setting.
Date: June 5, 2000
Creator: HANSEN,FRANCIS D.
Object Type: Article
System: The UNT Digital Library
Mathematical and Numerical Approaches in Performance Assessment for Radioactive Waste Disposal: Dealing with Uncertainty (open access)

Mathematical and Numerical Approaches in Performance Assessment for Radioactive Waste Disposal: Dealing with Uncertainty

None
Date: June 5, 2000
Creator: HELTON,JON CRAIG
Object Type: Article
System: The UNT Digital Library
Developing ''SMART'' equipment and systems through collaborative NERI research and development (open access)

Developing ''SMART'' equipment and systems through collaborative NERI research and development

The United States Department of Energy initiated the Nuclear Energy Research Initiative (NERI) to conduct research and development with the objectives of: (1) overcoming the principal technical obstacles to expanded nuclear energy use, (2) advancing the state of nuclear technology to maintain its competitive position in domestic and world markets, and (3) improving the performance, efficiency, reliability, and economics of nuclear energy. Fiscal Year 1999 program funding is $19 Million, with increased finding expected for subsequent years, emphasizing international cooperation. Among the programs selected for funding is the ``Smart Equipment and Systems to Improve Reliability and Safety in Future Nuclear Power Plant Operations''. This program is a 30 month collaborative effort bringing together the technical capabilities of ABB C-E Nuclear Power, Inc. (ABB CENP), Sandia National Laboratories, Duke Engineering and Services (DE and S), Massachusetts Institute of Technology (MIT) and Pennsylvania State University (PSU). The program's goal is to design, develop and evaluate an integrated set of smart equipment and predictive maintenance tools and methodologies that will significantly reduce nuclear plant construction, operation and maintenance costs. To accomplish this goal the Smart Equipment program will: (1) Identify and prioritize nuclear plant equipment that would most likely benefit from adding smart …
Date: June 5, 2000
Creator: Harmon, Daryl L.; Chapman, Leon D.; Golay, Michael W.; Maynard, Kenneth P. & Spencer, Joseph W.
Object Type: Article
System: The UNT Digital Library
A historical review of Waste Isolation Pilot Plant backfill development (open access)

A historical review of Waste Isolation Pilot Plant backfill development

Backfills have been part of Sandia National Laboratories' [Sandia's] Waste Isolation Pilot Plant [WIPP] designs for over twenty years. Historically, backfill research at Sandia has depended heavily on the changing mission of the WIPP facility. Early testing considered heat producing, high level, wastes. Bentonite/sand/salt mixtures were evaluated and studies focused on developing materials that would retard brine ingress, sorb radionuclides, and withstand elevated temperatures. The present-day backfill consists of pure MgO [magnesium oxide] in a pelletized form and is directed at treating the relatively low contamination level, non-heat producing, wastes actually being disposed of in the WIPP. Its introduction was motivated by the need to scavenging CO{sub 2} [carbon dioxide] from decaying organic components in the waste. However, other benefits, such as a substantial desiccating capacity, are also being evaluated. The MgO backfill also fulfills a statutory requirement for assurance measures beyond those needed to demonstrate compliance with the US Environmental Protection Agency [EPA] regulatory release limits. However, even without a backfill, the WIPP repository design still operates within EPA regulatory release limits.
Date: June 5, 2000
Creator: KRUMHANSL,JAMES L.; MOLECKE,MARTIN A.; PAPENGUTH,HANS W. & BRUSH,LAURENCE H.
Object Type: Article
System: The UNT Digital Library
Review of an Upgrade to a Low Energy Lung Monitor; Comparison of Empirically Determined Decision Levels Using ACT-II vs. ACT-1 Detectors, and Development and Use of Decision Levels I N an IN VITRO Bioassay Program Using ABACOS 2000 (open access)

Review of an Upgrade to a Low Energy Lung Monitor; Comparison of Empirically Determined Decision Levels Using ACT-II vs. ACT-1 Detectors, and Development and Use of Decision Levels I N an IN VITRO Bioassay Program Using ABACOS 2000

In this paper the work previously reported in 1994 on the theory, development and use of empirically determined decision levels in an in vivo bioassay program is discussed. Recently performed hardware and software upgrades to the Low Energy Lung Monitor (LELM) are also discussed. New data that was collected after the upgrades is provided. The new data is compared to and contrasted with the data that was collected prior to the upgrades. Details on the use of ABACOS 2000 software to accomplish decision level reporting are provided.
Date: June 5, 2000
Creator: Lawson, B. J.; Billings, Lawrence, J.; Ditoro, Diane C. & Lonergan, W. P.
Object Type: Article
System: The UNT Digital Library
Use of PHEBUS-FP Results in the NRC R&D Programme on Severe Accidents (open access)

Use of PHEBUS-FP Results in the NRC R&D Programme on Severe Accidents

None
Date: June 5, 2000
Creator: Lee, R. Y. & Powers, Dana A.
Object Type: Article
System: The UNT Digital Library
The Skill (Education) Distribution of Jobs: How Is It Changing? (open access)

The Skill (Education) Distribution of Jobs: How Is It Changing?

None
Date: June 5, 2000
Creator: Levine, Linda
Object Type: Report
System: The UNT Digital Library
Clean Air Act Issues in the 106th Congress (open access)

Clean Air Act Issues in the 106th Congress

This report provides information about the Clean Air Act Issues in the 106th Congress. Congress last enacted major amendments to the clear air act in 1990 and EPA is in the midst of implementing numerous provisions of those amendments.
Date: June 5, 2000
Creator: McCarthy, James E.
Object Type: Report
System: The UNT Digital Library
Materials Issues in Modern Reactor Safety (open access)

Materials Issues in Modern Reactor Safety

None
Date: June 5, 2000
Creator: Powers, Dana A.
Object Type: Article
System: The UNT Digital Library
Technical Issues Associated with Air Ingression During Core Degradation (open access)

Technical Issues Associated with Air Ingression During Core Degradation

This paper has shown that it is possible to get significant air intrusion into a ruptured reactor vessel even from a reactor cavity with restricted access. This suggests that there is some importance to considering the consequences of air intrusion following vessel penetration by core debris. The consequences will depend on the nature of core degradation in air and other oxidizing gases. If, indeed, fuel becomes exposed to strongly oxidizing gases, significant releases of ruthenium and hexavalent urania can be expected. Hexavalent urania could alter the nature of cesium release and cesium revaporization from the reactor coolant system. Hexavalent urania could destabilize CSI and enhance the formation of gaseous iodine unless there are other materials that will react readily with atomic iodine along the flow path to the reactor containment.
Date: June 5, 2000
Creator: Powers, Dana A.
Object Type: Article
System: The UNT Digital Library
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 84, No. 227, Ed. 1 Monday, June 5, 2000 (open access)

Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 84, No. 227, Ed. 1 Monday, June 5, 2000

Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date: June 5, 2000
Creator: Quinnelly, Lorrie J.
Object Type: Newspaper
System: The Gateway to Oklahoma History
Analysis and Summary Report of Historical Dry Well Gamma Logs for the 241-B Tank Farm 200 East (open access)

Analysis and Summary Report of Historical Dry Well Gamma Logs for the 241-B Tank Farm 200 East

This report provides a summary of the gross gamma ray data for the 241-B Tank Farm and is intended to identify changes in the gamma activity of gamma-emitting radionuclide contaminants around each accessible borehole, and is not intended to provide interpretation of the data relative to vadose zone mechanics. Trends in data, as well as areas where additional information would be helpful in evaluating the unusual nature of some of the data, are discussed.
Date: June 5, 2000
Creator: SYDNOR, H.A.
Object Type: Report
System: The UNT Digital Library
Analysis and Summary Report of Historical Dry Well Gamma Logs for the 241-T Tank Farm 200 West (open access)

Analysis and Summary Report of Historical Dry Well Gamma Logs for the 241-T Tank Farm 200 West

This report provides a summary of the gross gamma ray data for the 241-T Tank Farm and is intended to identify changes in the gamma activity of gamma-emitting radionuclide contaminants around each accessible borehole.
Date: June 5, 2000
Creator: SYDNOR, H.A.
Object Type: Report
System: The UNT Digital Library
Correlating Observations of Deformation Microstructures by TEM and Automated EBSD Techniques (open access)

Correlating Observations of Deformation Microstructures by TEM and Automated EBSD Techniques

The evolution of the deformed microstructure as a function of imposed plastic strain is of interest as it provides information on the material hardening characteristics and mechanism(s) by which cold work energy is stored. This has been extensively studied using transmission electron microscopy (TEM), where the high spatial and orientational resolution of the technique is used to advantage to study local phenomenon such as dislocation core structures and interactions of dislocations. With the recent emergence of scanning electron microscope (SEM) based automated electron backscatter diffraction (EBSD) techniques, it has now become possible to make mesoscale observations that are statistical in nature and complement the detailed TEM observations. Correlations of such observations will be demonstrated for the case of Ni-base alloys, which are typically non-cell forming solid solution alloys when deformed at ambient temperatures. For instance, planar slip is dominant at low strain levels but evolves into a microstructure where distinct crystallographic dislocation-rich walls form as a function of strain and grain orientation. Observations recorded using both TEM and EBSD techniques are presented and analyzed for their implication on subsequent annealing characteristics.
Date: June 5, 2000
Creator: Schwartz, A.J. & King, W.E.
Object Type: Article
System: The UNT Digital Library
The Alvin Sun (Alvin, Tex.), Vol. 109, No. 46, Ed. 1 Monday, June 5, 2000 (open access)

The Alvin Sun (Alvin, Tex.), Vol. 109, No. 46, Ed. 1 Monday, June 5, 2000

Weekly newspaper from Alvin, Texas that includes local, state, and national news along with advertising.
Date: June 5, 2000
Creator: Schwind, Jim & Holton, Kathleen
Object Type: Newspaper
System: The Portal to Texas History
Hanford Diversification and the Tri-Cities Economy FY 1999 (open access)

Hanford Diversification and the Tri-Cities Economy FY 1999

The missions of the U.S. Department of Energy's Richland Operations Office (DOE/RL) are to safely manage the Hanford Site, to manage and clean up its legacy wastes, and to develop and deploy new science and technology in the environmental and energy fields. Collectively, DOE/RL and its contractors are the most important single entity in the Tri-Cities local economy (Pasco, Kennewick, and Richland, Washington, and the surrounding area). Although the relevant economic region affected by DOE/RL and its contractors actually embraces a geographic area reaching from Yakima in the west to Walla Walla in the east and from Moses Lake in the north to Pendleton, Oregon, in the south, over 90% of economic impacts likely occur in Benton and Franklin Counties. These two counties are defined as the ''local'' Tri-Cities economy for purposes of this study. In the federal fiscal year (FY) 1999 (October 1, 1998 through September 30, 1999), the total impact of DOE'S local $1.59 billion budget was felt through payrolls of $542 million and local purchases of goods and services of $226 million. The total local spending of $768 million was up slightly from the FY 1998 total of $765 million. Taking into account the multiplier effects of …
Date: June 5, 2000
Creator: Scott, M. J.
Object Type: Report
System: The UNT Digital Library