Resource Type

Prediction of Corrosion of Alloys in Mixed-Solvent Environments (open access)

Prediction of Corrosion of Alloys in Mixed-Solvent Environments

Corrosion is much less predictable in organic or mixed-solvent environments than in aqueous process environments. As a result, US chemical companies face greater uncertainty when selecting process equipment materials to manufacture chemical products using organic or mixed solvents than when the process environments are only aqueous. Chemical companies handle this uncertainty by overdesigning the equipment (wasting money and energy), rather than by accepting increased risks of corrosion failure (personnel hazards and environmental releases). Therefore, it is important to develop simulation tools that would help the chemical process industries to understand and predict corrosion and to develop mitigation measures. To create such tools, we have developed models that predict (1) the chemical composition, speciation, phase equilibria, component activities and transport properties of the bulk (aqueous, nonaqueous or mixed) phase that is in contact with the metal; (2) the phase equilibria and component activities of the alloy phase(s) that may be subject to corrosion and (3) the interfacial phenomena that are responsible for corrosion at the metal/solution or passive film/solution interface. During the course of this project, we have completed the following: (1) Development of thermodynamic modules for calculating the activities of alloy components; (2) Development of software that generates stability diagrams …
Date: June 5, 2003
Creator: A. Anderko, P. Wang, R. D. Young, D. P. Riemer, P. McKenzie and M. M. Lencka (OLI Systems Inc.) & Laboratory), S. S. Babu and P. Angelini (Oak Ridge National
System: The UNT Digital Library
Parallel Ion Energy Spread Due to Interaction With an Electron Bunch in the RHIC Electron Beam Cooling Solenoid (open access)

Parallel Ion Energy Spread Due to Interaction With an Electron Bunch in the RHIC Electron Beam Cooling Solenoid

N/A
Date: June 1, 2003
Creator: A., Hershcovitch
System: The UNT Digital Library
Migration and Entrapment of DNAPLs in Heterogeneous Systems: Impact of Waste and Porous Medium Composition (open access)

Migration and Entrapment of DNAPLs in Heterogeneous Systems: Impact of Waste and Porous Medium Composition

Previously funded EMSP research efforts were directed towards the quantification of dense non-aqueous phase liquid (DNAPL) migration and entrapment behavior in physically and chemically heterogeneous systems. This research demonstrated that chemical heterogeneities can have a significant influence on DNAPL fate and persistence. Previous work, however, was limited to examination of the behavior of pure DNAPLs in systems with simple and well-defined aqueous and solid surface chemistry. The subsurface chemical environments at many DOE sites, however, are generally more complex than these idealized systems, due to the release of complex mixtures of wastes and more complex physical and chemical heterogeneity. The research undertaken in this project seeks to build upon our previous research experience and expertise to explore the influence of waste and porous media composition on DNAPL migration and entrapment in the saturated zone. DNAPL mixtures and soils typical of those found across the DOE complex will be used in these studies. Many of the experimental procedures and protocols are based upon those developed under previous EMSP funding. This past work also provides the conceptual framework for characterizing and interpreting experimental results, mathematical model development, and inverse modeling protocols. Specific objectives of this research include: (1) Relate measured interfacial properties …
Date: June 1, 2003
Creator: Abriola, Linda M. & Demond, Avery H.
System: The UNT Digital Library
Waste Form and Indrift Colloids-Associated Radionuclide Concentrations: Abstraction and Summary (open access)

Waste Form and Indrift Colloids-Associated Radionuclide Concentrations: Abstraction and Summary

This Model Report describes the analysis and abstractions of the colloids process model for the waste form and engineered barrier system components of the total system performance assessment calculations to be performed with the Total System Performance Assessment-License Application model. Included in this report is a description of (1) the types and concentrations of colloids that could be generated in the waste package from degradation of waste forms and the corrosion of the waste package materials, (2) types and concentrations of colloids produced from the steel components of the repository and their potential role in radionuclide transport, and (3) types and concentrations of colloids present in natural waters in the vicinity of Yucca Mountain. Additionally, attachment/detachment characteristics and mechanisms of colloids anticipated in the repository are addressed and discussed. The abstraction of the process model is intended to capture the most important characteristics of radionuclide-colloid behavior for use in predicting the potential impact of colloid-facilitated radionuclide transport on repository performance.
Date: June 24, 2003
Creator: Aguilar, R.
System: The UNT Digital Library
Level Densities and Radiative Strength Functions in 170,171Yb (open access)

Level Densities and Radiative Strength Functions in 170,171Yb

Level densities and radiative strength functions in {sup 171}Yb and{sup 170}Yb nuclei have been measured with the {sup 171}Yb({sup 3}He, {sup 3}He{prime}{gamma}){sup 171}Yb and {sup 171}Yb({sup 3}He,{alpha}{gamma}){sup 170}Yb reactions. A simultaneous determination of the nuclear level density and the radiative strength function was made. The present data adds to and is consistent with previous results for several other rare earth nuclei. The method will be briefly reviewed and the result from the analysis will be presented. The radiative strength function for {sup 171}Yb is compared to previously published work.
Date: June 9, 2003
Creator: Agvaanluvsan, U.; Schiller, A.; Becker, J. A.; Berstein, L. A.; Guttormsen, M.; Mitchell, G. E. et al.
System: The UNT Digital Library
Science Based Stockpile Stewardship and RIA (open access)

Science Based Stockpile Stewardship and RIA

One aspect of Science Based Stockpile Stewardship (SBSS) is to improve the quality of neutron cross section data for certain isotopes. The isotopes of interest are used to monitor neutron and charged particle fluxes in environments of brief, intense neutron fluxes. The accuracy of flux determination is dependent on the accuracy of cross section data for the stable isotopes loaded into the system and the unstable isotopes produced when the neutrons are incident on the monitor. For isotopes with a half-life greater than one day it is possible, given the production rates of RIA, to make radioactive targets for neutron irradiation. This would require the ability to harvest isotopes at RIA, an onsite radiochemistry facility for processing the harvested material into a target, and an onsite neutron source facility. The radiochemistry facility will need to handle activity levels on the order of 100's of Curie's while the neutron source facility will need to provide high intensity ''monoenergetic'' neutrons from 10's keV to 20 MeV. For isotopes with a half-life much less than one day, only indirect methods can be used to get information on the neutron cross sections because of the lack of a target. Both experimental techniques will be …
Date: June 9, 2003
Creator: Ahle, L. E.; Bernstein, L. A.; Hausmann, M. & Vieira, D. J.
System: The UNT Digital Library
EARLY ENTRANCE COPRODUCTION PLANT (open access)

EARLY ENTRANCE COPRODUCTION PLANT

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstocks. The objectives of Phase I were to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan for implementation in Phase II; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and/or other carbonaceous feedstocks. The objective of Phase III is to develop an engineering design package and a financing and testing …
Date: June 9, 2003
Creator: Ahmed, Mushtaq; Anderson, John H.; Benham, Charles; Berry, Earl R.; Brent, Fred; Demirel, Belma et al.
System: The UNT Digital Library
Contaminant-Organic Complexes: Their Structure and Energetics in Surface Decontamination Processes (open access)

Contaminant-Organic Complexes: Their Structure and Energetics in Surface Decontamination Processes

The current debate over possible decontamination processes for DOE facilities is centered on disparate decontamination problems, but the key contaminants (Thorium [Th],uranium [U], and plutonium [Pu]) are universally important. Innovative agents used alone or in conjunction with traditional processes can increase the potential to reclaim for future use some these valuable resources or at the least decontaminate the metal surfaces to allow disposal as nonradioactive, nonhazardous material. This debate underscores several important issues: (1) regardless of the decontamination scenario, metal (Fe, U, Pu, Np) oxide film removal from the surface is central to decontamination; and (2) simultaneous oxide dissolution and sequestration of actinide contaminants against re-adsorption to a clean metal surface will influence the efficacy of a process or agent and its cost. Current research is investigating the use of microbial siderophores (chelates) to solubilize actinides (i.e., Th, U, Pu) from the surface of Fe oxide surfaces. Continuing research integrates (1) studies of macroscopic dissolution/desorption of common actinide (IV) [Th, U, Pu, Np] solids and species sorbed to and incorporated into Fe oxides, (2) molecular spectroscopy (FTIR, Raman, XAS), to probe the structure and bonding of contaminants, siderophores and their functional moieties, and how these change with the chemical environment, …
Date: June 2003
Creator: Ainsworth, Calvin C.; Hay, Benjamin P.; Traina, Samuel J. & Myneni, Satish C. B.
System: The UNT Digital Library
A Review of Methods for the Manufacture of Residential RoofingMaterials (open access)

A Review of Methods for the Manufacture of Residential RoofingMaterials

Shingles, tiles, and metal products comprise over 80% (by roof area) of the California roofing market (54-58% fiberglass shingle, 8-10% concrete tile, 8-10% clay tile, 7% metal, 3% wood shake, and 3% slate). In climates with significant demand for cooling energy, increasing roof solar reflectance reduces energy consumption in mechanically cooled buildings, and improves occupant comfort in non-conditioned buildings. This report examines methods for manufacturing fiberglass shingles, concrete tiles, clay tiles, and metal roofing. The report also discusses innovative methods for increasing the solar reflectance of these roofing materials. We have focused on these four roofing products because they are typically colored with pigmented coatings or additives. A better understanding of the current practices for manufacturing colored roofing materials would allow us to develop cool colored materials creatively and more effectively.
Date: June 1, 2003
Creator: Akbari, Hashem; Levinson, Ronnen & Berdahl, Paul
System: The UNT Digital Library
Liquid film/polymer interfaces (open access)

Liquid film/polymer interfaces

The objectives were: (1) Through experimental studies, advance the fundamental understanding of the principles that govern adsorption and wetting phenomena at polymer and organic surfaces. (2) Establish a firm scientific basis for improving the design of coatings for metal fin cooling surfaces used to control the wetting of water condensate for optimum energy efficiency. Several important findings were: (1) water adsorbed at hydrophobic surfaces has a liquid-like structure, in contrast to the generally held view of an ordered structure; (2) Correlations of large amounts of contact angle wetting data of grafted alkyl chain compounds showed a distinct link between the contact angle and the conformational ordering of the chains; (3) water adsorption at long chain alkysiloxane films showed a strong pH dependence on the film stability, which can be attributed to interfacial chemical effects on the siloxane network.
Date: June 12, 2003
Creator: Allara, David L.
System: The UNT Digital Library
Reactive Multiphase Behavior of C)2 in Saline Aquifers Beneath the Colorado Plateau (open access)

Reactive Multiphase Behavior of C)2 in Saline Aquifers Beneath the Colorado Plateau

The six coal-fired power plants located in the Colorado Plateau and southern Rocky Mountain region of the U.S. produce 100 million tons of CO{sub 2} per year. Thick sequences of collocated sedimentary rocks represent potential sites for sequestration of the CO{sub 2}. Field and laboratory investigations of naturally occurring CO{sub 2}-reservoirs are being conducted to determine the characteristics of potential seal and reservoir units and the extent of the interactions that occur between the host rocks and the CO{sub 2} charged fluids. The results are being incorporated into a series of two-dimensional numerical models that represent the major chemical and physical processes induced by injection. During reporting period covered here (March 30 to June 30, 2003), the main achievements were: Presentation of three papers at the Second Annual Conference on Carbon Sequestration (May 5-8, Alexandria, Virginia); Presentation of a poster at the American Association of Petroleum Geologists meeting; Co-PI organized and chaired a special session on Geologic Carbon Dioxide Sequestration at the American Association of Petroleum Geologists annual convention in Salt Lake City (May 12-15).
Date: June 30, 2003
Creator: Allis, R. G.; Moore, J. & White, S.
System: The UNT Digital Library
A Resolution Analysis of Two Geophysical Imaging Methods for Characterizing and Monitoring Hydrologic Conditions in the Vadose Zone (open access)

A Resolution Analysis of Two Geophysical Imaging Methods for Characterizing and Monitoring Hydrologic Conditions in the Vadose Zone

This project has been designed to analyze the resolution of two different geophysical imaging techniques (electrical resistivity tomography and cross-borehole ground penetrating radar) for monitoring subsurface flow and transport processes within the vadose zone. This is to be accomplished through a coupled approach involving large scale unsaturated flow modeling, petrophysical conversion of the resulting 2 and 3 Dimensional water content and solute concentration fields to geophysical property models and generation of synthetic geophysical data, followed by the inversion of the synthetic geophysical data. The resolution, strengths, and limitations of the geophysical techniques will then be ascertained through an analysis involving comparisons between the original hydrologic modeling results and inverted geophysical images. Increasing levels of complexity will be added to the models as the project progresses through the addition of heterogeneity in the original hydrologic property model, and by adding uncertainty to the petrophysical relationship that couples the geophysical model to the hydrologic modeling results.
Date: June 1, 2003
Creator: Alumbaugh, David L.
System: The UNT Digital Library
A RESOLUTION ANALYSIS OF TWO GEOPHYSICAL IMAGING METHODS FOR CHARACTERIZING AND MONITORING HYDROLOGIC CONDITIONS IN THE VADOSE ZONE (open access)

A RESOLUTION ANALYSIS OF TWO GEOPHYSICAL IMAGING METHODS FOR CHARACTERIZING AND MONITORING HYDROLOGIC CONDITIONS IN THE VADOSE ZONE

The objective of this study is to characterize and analyze in-situ flow and transport within the vadose zone during a mid-scale hydrologic infiltration experiment. This project has employed numerical and experimental tools developed under a previously funded EMSP proposal (project number 55332) to provide 3-D unsaturated hydrologic property distributions. In the present project, geophysical imaging techniques have been employed to track analogue contaminant plumes. The results are providing a better understanding of transport modes including the influence of natural heterogeneities and man-made structures within the vadose zone at DOE sites. In addition the data is providing checks against which numerical flow and transport simulations can be compared
Date: June 4, 2003
Creator: Alumbaugh, David L. & Brainard, James R.
System: The UNT Digital Library
A RESOLUTION ANALYSIS OF TWO GEOPHYSICAL IMAGING METHODS FOR CHARACTERIZING AND MONITORING HYDROLOGIC CONDITIONS IN THE VADOSE ZONE (open access)

A RESOLUTION ANALYSIS OF TWO GEOPHYSICAL IMAGING METHODS FOR CHARACTERIZING AND MONITORING HYDROLOGIC CONDITIONS IN THE VADOSE ZONE

The objective of this study is to characterize and analyze in-situ flow and transport within the vadose zone during a mid-scale hydrologic infiltration experiment. This project has employed numerical and experimental tools developed under a previously funded EMSP proposal (project number 55332) to provide 3-D unsaturated hydrologic property distributions. In the present project, geophysical imaging techniques have been employed to track analogue contaminant plumes. The results are providing a better understanding of transport modes including the influence of natural heterogeneities and man-made structures within the vadose zone at DOE sites. In addition the data is providing checks against which numerical flow and transport simulations can be compared.
Date: June 1, 2003
Creator: Alumbaugh, David L. & Brainard, James R.
System: The UNT Digital Library
Future CIS Manufacturing Technology Development: Final Report, 8 July 1998--17 October 2001 (open access)

Future CIS Manufacturing Technology Development: Final Report, 8 July 1998--17 October 2001

The University of Florida served as the basis for educating 12 graduate students in the area of photovoltaics engineering and research with a focus on thin-film CIS manufacturing technologies. A critical assessment of the thermodynamic data and of the phase diagrams for the Cu-Se and In-Se binary systems were carried out. We investigated the use of two novel precursor structures that used stacked In-Se and Cu-Se binary layers instead of conventional elemental layers, followed by rapid thermal processing (RTP) to produce CIS films. We investigated the evolution of electrical and microstructural properties of sputter-deposited ZnO:Al thin films. An assessment of the thermodynamics of the pseudobinary Cu2Se-Ga2Se3 system was done by using available experimental data, as well as an empirical method for estimating interactions in semiconductor solid solutions. Optimization studies were conducted to characterize the RTP of binary bilayer precursors for CIS synthesis using a newly acquired AG Associates Heatpulse furnace. Progress was made on the calculation of the 500C isothermal section of the phase diagram of the ternary Cu-In-Se system. Pursuit of developing alternative buffer layers for Cd-free CIS-based solar cells using a chemical-bath deposition (CBD) process has resulted in specific recipes for deposition. A rigorous model has been derived …
Date: June 1, 2003
Creator: Anderson, T. J.; Crisalle, O. D.; Li, S. S. & Holloway, P. H.
System: The UNT Digital Library
SULFUR REDUCTION IN GASOLINE AND DIESEL FUELS BY EXTRACTION/ADSORPTION OF REFRACTORY DIBENZOTHIOPHENES (open access)

SULFUR REDUCTION IN GASOLINE AND DIESEL FUELS BY EXTRACTION/ADSORPTION OF REFRACTORY DIBENZOTHIOPHENES

Refractory 4,6-dimethyldibenzothiophene, which is difficult to remove from petroleum feedstocks, binds to the Ru in Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} by displacing the H{sub 2}O ligand. Thiophene, benzothiophene and dibenzothiophene (DBT) also react with Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} similarly. This binding ability of Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} has been used to remove over 50% of the DBT in simulated petroleum feedstocks by a biphasic extraction process. The extraction phase is readily regenerated by air-oxidation thereby completing a cyclic process that removes DBT from petroleum feedstocks. Solid phase extractants consisting of Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+}, CpRu(CO){sub 2}(BF{sub 4}), CpFe(CO){sub 2}(C{sub 4}H{sub 8}){sup +} and AgX (where X = BF{sub 4}{sup -}, PF{sub 6}{sup -} or NO{sub 3}{sup -}) adsorbed on silica have also been used to remove DBT and 4,6-Me{sub 2}DBT from simulated petroleum feedstocks. The AgX/silica adsorbents remove 90% of the DBT and 4,6-Me{sub 2}DBT and can be regenerated and re-used for multiple extractions, which makes these adsorbents of potential industrial use for the removal of refractory dibenzothiophenes from petroleum feedstocks.
Date: June 1, 2003
Creator: Angelici, Robert J.
System: The UNT Digital Library
Measurement of the Auger Recombination Rate in p-type 0.54-eV GaInAsSb by Time-Resolved Photoluminescence (open access)

Measurement of the Auger Recombination Rate in p-type 0.54-eV GaInAsSb by Time-Resolved Photoluminescence

Auger recombination in p-type GaSb, InAs and their alloys is enhanced due to the proximity of the bandgap energy and the energy separation to the spin split-off valence band. This can affect the device performance even at moderate doping concentration. They report electron lifetime measurements in a p-type 0.54-eV GaInAsSb alloy, commonly used in a variety of infrared devices. They have studied a series of double-capped heterostructures with varied thicknesses and doping levels, grown by organometallic vapor phase epitaxy on GaSb substrates. The Auger coefficient value of 2.3 x 10{sup -28} cm{sup 6}/s is determined by analyzing the photoluminescence decay constants with a systematic separation of different recombination mechanisms.
Date: June 13, 2003
Creator: Anikeev, S.; Donetsky, D.; Belenky, G.; Luryi, S.; Wang, C.A.; Borrego, J.M. et al.
System: The UNT Digital Library
Co-Firing Coal: Feedlot and Litter Biomass Fuels Quarterly Progress Report #11: December 2002 - March 2003 (open access)

Co-Firing Coal: Feedlot and Litter Biomass Fuels Quarterly Progress Report #11: December 2002 - March 2003

Reburn with animal waste yield NO{sub x} reduction of the order of 70-80%, which is much higher than those previously reported in the literature for natural gas, coal and agricultural biomass as reburn fuels. Further, the NO{sub x} reduction is almost independent of stoichiometry from stoichiometric to upto 10% deficient air in reburn zone. As a first step towards understanding the reburn process in a boiler burner, a simplified zero-dimensional model has been developed for estimating the NO{sub x} reduction in the reburn process using simulated animal waste based biomass volatiles. However the first model does not include the gradual heat up of reburn fuel particle, pyrolysis and char combustion. Hence there is a need for more rigorous treatment of the model with animal waste as reburn fuel. To address this issue, an improved zero-dimensional model is being developed which can handle any solid reburn fuel, along with more detailed heterogeneous char reactions and homogeneous global reactions. The model on ''NO{sub x} Reduction for Reburn Process using Feedlot Biomass,'' incorporates; (a) mixing between reburn fuel and main-burner gases, (b) gradual heat-up of reburn fuel accompanied by pyrolysis, oxidation of volatiles and char oxidation, (c) fuel-bound nitrogen (FBN) pyrolysis, and FBN …
Date: June 2003
Creator: Annamalai, Kalyan; Sweeten, John; Mukhtar, Saqib & Priyadarsan, Soyuz
System: The UNT Digital Library
Renewable Energy in Water and Wastewater Treatment Applications; Period of Performance: April 1, 2001--September 1, 2001 (open access)

Renewable Energy in Water and Wastewater Treatment Applications; Period of Performance: April 1, 2001--September 1, 2001

This guidebook will help readers understand where and how renewable energy technologies can be used for water and wastewater treatment applications. It is specifically designed for rural and small urban center water supply and wastewater treatment applications. This guidebook also provides basic information for selecting water resources and for various kinds of commercially available water supply and wastewater treatment technologies and power sources currently in the market.
Date: June 1, 2003
Creator: Argaw, N.
System: The UNT Digital Library
Environmental Management Science Program (EMSP) Annual Report (open access)

Environmental Management Science Program (EMSP) Annual Report

The treatment or remediation of contaminants at some sites is neither technically nor economically feasible. Containment or stabilization of these subsurface contaminants, therefore, may be the only viable alternative for the protection of human and ecological health. The overall goal of the proposed research is the development of reactive membrane barriers which dramatically enhance containment. Reactive particles in these barriers serve to either immobilize or transform contaminants within the membrane, and thus increase the time to breakthrough. These membranes are a powerful, novel, and versatile technique to contain and stabilize subsurface contaminants. This work focuses on reactive membrane barriers containing either zero-valent iron (Fe0) particles (which can reduce metals and chlorinated solvents) or crystalline silicotitanate (CST, a selective ion exchanger of cesium and strontium) particles.
Date: June 1, 2003
Creator: Arnold, William A. & Cussler, Edward L.
System: The UNT Digital Library
Reactive Membrane Barriers for Containment of Subsurface Contamination (open access)

Reactive Membrane Barriers for Containment of Subsurface Contamination

This report summarizes work after fifteen months of a three-year project. The project is part of a larger effort to improve barrier properties of any polymer by 10,000 times. This implies that any polymer barrier now good for a day will be made effective for a decade. We use two strategies to achieve these improvements. The first, primarily supported by the Air Force Office of Scientific Research, uses aligned impermeable flakes of mica, clay, and other materials to enhance barrier properties 10 to 100 times. The barrier works against all diffusing species. This strategy, which we are applying to make corrosion resistant paints, works both in the unsteady state and in the steady state. Our second strategy, supported by this grant, uses reagents within the barrier polymer to neutralize specific species. This strategy works only in the unsteady state, while the reagents last. It is extremely effective, however, sometimes achieving increases in barrier properties of 1000 times or more.
Date: June 1, 2003
Creator: Arnold, William A. & Cussler, Edward L.
System: The UNT Digital Library
Field-Scale In Situ Measurements of Vadose Zone Flow and Transport Using Multiple Tracers at INEEL Vadose Zone Research Park (VZRP) (open access)

Field-Scale In Situ Measurements of Vadose Zone Flow and Transport Using Multiple Tracers at INEEL Vadose Zone Research Park (VZRP)

This study is aimed at obtaining a better understanding of vadose zone flow and transport processes at the field scale and establishing defensible links between laboratory- and field-derived transport parameters for conservative and reactive elements in the vadose zone. The study site (Vadose Zone Research Park [VZRP] at INEEL) provides a three dimensional instrumentation array strategically surrounding a new infiltration pond slated for initial use in the upcoming year, and the Big Lost River, and intermittent stream proximal to the infiltration ponds. The proposed research will utilize the infiltration ponds and the Big Lost River to study the effects of fluid flux, water chemistry and degree of saturation on contaminant transport in the vadose zone. Our research plan has four major objectives: (1) determine the transport of conservative and reactive solute and colloid tracers through the vadose zone and local perched water zones; (2) examine isotopic variations of U and Sr an d compare these to introduced sorbing and non-sorbing tracers; (3) develop and calibrate a conceptual flow and transport model, and (4) examine the effects of flow and geochemical transients on tracer transport.
Date: June 1, 2003
Creator: Asmerom, Yemane
System: The UNT Digital Library
Measurement of the Nickel/Nickel Oxide Transition in Ni-Cr-Fe Alloys and Updated Data and Correlations to Quantify the Effect of Aqueous Hydrogen on Primary Water SCC (open access)

Measurement of the Nickel/Nickel Oxide Transition in Ni-Cr-Fe Alloys and Updated Data and Correlations to Quantify the Effect of Aqueous Hydrogen on Primary Water SCC

Alloys 600 and X-750 have been shown to exhibit a maximum in primary water stress corrosion cracking (PWSCC) susceptibility, when testing is conducted over a range of aqueous hydrogen (H{sub 2}) levels. Contact electric resistance (CER) and corrosion coupon testing using nickel specimens has shown that the maximum in SCC susceptibility occurs in proximity to the nickel-nickel oxide (Ni/NiO) phase transition. The measured location of the Ni/NiO transition has been shown to vary with temperature, from 25 scc/kg H{sub 2} at 360 C to 4 scc/kg H{sub 2} at 288 C. New CER measurements show that the Ni/NiO transition is located at 2 scc/kg H{sub 2} at 260 C. An updated correlation of the phase transition is provided. The present work also reports CER testing conducted using an Alloy 600 specimen at 316 C. A large change in resistance occurred between 5 and 10 scc/kg H{sub 2}, similar to the results obtained at 316 C using a nickel specimen. This result adds confidence in applying the Ni/NiO transition measurements to Ni-Cr-Fe alloys. The understanding of the importance of the Ni/NiO transition to PWSCC has been used previously to quantify H{sub 2} effects on SCC growth rate (SCCGR). Specifically, the difference …
Date: June 16, 2003
Creator: Attanasio, Steven A. & Morton, David S.
System: The UNT Digital Library
NREL Wind Site Entrance Building: Design Review and Recommendations (open access)

NREL Wind Site Entrance Building: Design Review and Recommendations

Report giving review of the NREL Wind Site Guard Post Entrance building design and recommendations for improvement for greater energy savings and backup power.
Date: June 1, 2003
Creator: Ault, R.; Torcellini, P. & Van Geet, O.
System: The UNT Digital Library