States

Evolution of porosity and diffusivity associated with chemical weathering of a basalt clast (open access)

Evolution of porosity and diffusivity associated with chemical weathering of a basalt clast

Weathering of rocks as a result of exposure to water and the atmosphere can cause significant changes in their chemistry and porosity. In low-porosity rocks, such as basalts, changes in porosity, resulting from chemical weathering, are likely to modify the rock's effective diffusivity and permeability, affecting the rate of solute transport and thus potentially the rate of overall weathering to the extent that transport is the rate limiting step. Changes in total porosity as a result of mineral dissolution and precipitation have typically been used to calculate effective diffusion coefficients through Archie's law for reactive transport simulations of chemical weathering, but this approach fails to account for unconnected porosity that does not contribute to transport. In this study, we combine synchrotron X-ray microcomputed tomography ({mu}CT) and laboratory and numerical diffusion experiments to examine changes in both total and effective porosity and effective diffusion coefficients across a weathering interface in a weathered basalt clast from Costa Rica. The {mu}CT data indicate that below a critical value of {approx}9%, the porosity is largely unconnected in the basalt clast. The {mu}CT data were further used to construct a numerical pore network model to determine upscaled, effective diffusivities as a function of total porosity …
Date: February 15, 2009
Creator: Navarre-Sitchler, A.; Steefel, C.I.; Yang, L.; Tomutsa, L. & Brantley, S.L.
Object Type: Article
System: The UNT Digital Library
PRELIMINARY FRIT DEVELOPMENT AND MELT RATE TESTING FOR SLUDGE BATCH 6 (SB6) (open access)

PRELIMINARY FRIT DEVELOPMENT AND MELT RATE TESTING FOR SLUDGE BATCH 6 (SB6)

The Liquid Waste Organization (LWO) provided the Savannah River National Laboratory (SRNL) with a Sludge Batch 6 (SB6) composition projection in March 2009. Based on this projection, frit development efforts were undertaken to gain insight into compositional effects on the predicted and measured properties of the glass waste form and to gain insight into frit components that may lead to improved melt rate for SB6-like compositions. A series of Sludge Batch 6 (SB6) based glasses was selected, fabricated and characterized in this study to better understand the ability of frit compositions to accommodate uncertainty in the projected SB6 composition. Acceptable glasses (compositions where the Product Composition Control System (PCCS) Measurement Acceptability Region (MAR) predicted acceptable properties, good chemical durability was measured, and no detrimental nepheline crystallization was observed) can be made using Frit 418 with SB6 over a range of Na{sub 2}O and Al{sub 2}O{sub 3} concentrations. However, the ability to accommodate variation in the sludge composition limits the ability to utilize alternative frits for potential improvements in melt rate. Frit 535, which may offer improvements in melt rate due to its increased B2O3 concentration, produced acceptable glasses with the baseline SB6 composition at waste loadings of 34 and 42%. …
Date: July 21, 2009
Creator: Fox, K.; Miller, D. & Edwards, T.
Object Type: Report
System: The UNT Digital Library
Expanded breadth of the T-cell response to mosaic HIV-1 envelope DNA vaccination (open access)

Expanded breadth of the T-cell response to mosaic HIV-1 envelope DNA vaccination

An effective AIDS vaccine must control highly diverse circulating strains of HIV-1. Among HIV -I gene products, the envelope (Env) protein contains variable as well as conserved regions. In this report, an informatic approach to the design of T-cell vaccines directed to HIV -I Env M group global sequences was tested. Synthetic Env antigens were designed to express mosaics that maximize the inclusion of common potential Tcell epitope (PTE) 9-mers and minimize the inclusion of rare epitopes likely to elicit strain-specific responses. DNA vaccines were evaluated using intracellular cytokine staining (ICS) in inbred mice with a standardized panel of highly conserved 15-mer PTE peptides. I, 2 and 3 mosaic sets were developed that increased theoretical epitope coverage. The breadth and magnitude ofT-cell immunity stimulated by these vaccines were compared to natural strain Env's; additional comparisons were performed on mutant Env's, including gpl60 or gpl45 with or without V regions and gp41 deletions. Among them, the 2 or 3 mosaic Env sets elicited the optimal CD4 and CD8 responses. These responses were most evident in CD8 T cells; the 3 mosaic set elicited responses to an average of 8 peptide pools compared to 2 pools for a set of3 natural Env's. …
Date: January 1, 2009
Creator: Korber, Bette; Fischer, William & Wallstrom, Timothy
Object Type: Article
System: The UNT Digital Library
STATISTICAL EVALUATION OF PROCESSING DATA FROM THE RH RU HG MATRIX STUDY (open access)

STATISTICAL EVALUATION OF PROCESSING DATA FROM THE RH RU HG MATRIX STUDY

An evaluation of the statistical significance of Rh, Ru, and Hg on DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle catalytic hydrogen generation and process chemistry was conducted by the Savannah River National Laboratory (SRNL) using a full-factorial experimental design. This test design can identify significant interactions between these three species in addition to individual effects. Statistical modeling of data from the Rh-Ru-Hg matrix study has been completed. Preliminary data and conclusions were given in an earlier report. This final report concludes the work on the Rh-Ru-Hg matrix study. Modeling results are summarized below. Rhodium was found to: Promote increased total hydrogen mass; Promote an increase in the maximum hydrogen generation rate; Promote an increase in the hydrogen generation rate shortly after acid addition; Shorten the elapsed time between acid addition and the maximum hydrogen generation rate; Increase formate loss; Inhibit NO{sub 2} and total NO{sub x} off-gas species formation; and Reduce nitrite-to-nitrate conversion. Ruthenium was found to: Promote increased total hydrogen mass; Promote an increase in the maximum hydrogen generation rate; Promote an increase in the hydrogen generation rate in the second half of the SRAT cycle; Promote an increase in total CO{sub 2} generated; Increase formate loss; Promote …
Date: April 17, 2009
Creator: Koopman, D
Object Type: Report
System: The UNT Digital Library
TIME-TEMPERATURE-TRANSFORMATION DIAGRAMS FOR THE SLUDGE BATCH 3 - FRIT 418 GLASS SYSTEM (open access)

TIME-TEMPERATURE-TRANSFORMATION DIAGRAMS FOR THE SLUDGE BATCH 3 - FRIT 418 GLASS SYSTEM

As a part of the Waste Acceptance Product Specifications (WAPS) for Vitrified High-Level Waste Forms defined by the Department of Energy - Office of Environmental Management, the phase stability must be determined for each of the projected high-level waste (HLW) types at the Savannah River Site (SRS). Specifically, WAPS 1.4.1 requires the glass transition temperature (Tg) to be defined and time-temperature-transformation (TTT) diagrams to be developed. The Tg of a glass is an indicator of the approximate temperature where the supercooled liquid converts to a solid on cooling or conversely, where the solid begins to behave as a viscoelastic solid on heating. A TTT diagram identifies the crystalline phases that can form as a function of time and temperature for a given waste type or more specifically, the borosilicate glass waste form. In order to assess durability, the Product Consistency Test (PCT) was used and the durability results compared to the Environmental Assessment (EA) glass. The measurement of glass transition temperature and the development of TTT diagrams have already been performed for the seven Defense Waste Processing Facility (DWPF) projected compositions as defined in the Waste Form Compliance Plan (WCP). These measurements were performed before DWPF start-up and the results …
Date: March 3, 2009
Creator: Billings, A & Tommy Edwards, T
Object Type: Report
System: The UNT Digital Library
INITIAL CHARACTERIZATIONS AND SRAT SIMULATIONS OF FOUR SLUDGE MATRIX STUDY SIMULANTS (open access)

INITIAL CHARACTERIZATIONS AND SRAT SIMULATIONS OF FOUR SLUDGE MATRIX STUDY SIMULANTS

The Savannah River National Laboratory (SRNL) initiated a sludge matrix study to evaluate the impact of changing insoluble solid composition on the processing characteristics of slurries in the Defense Waste Processing Facility (DWPF). Three compositional ranges were developed for three groups of elements in the waste. The first was high iron/low aluminum versus low iron/high aluminum. The second was high calcium-manganese/low nickel, chromium, and magnesium versus low calcium-manganese/high nickel, chromium, and magnesium. The third was high noble metals (Ag, Pd, Rh, Ru) versus low noble metals. These three options can be combined to form eight distinct sludge compositions. The sludge matrix study called for testing each of these eight simulants near the minimum acid required for nitrite destruction and at a second acid level that produced significant hydrogen by noble metal catalyzed decomposition of formic acid. Four simulants were prepared based on the four possible combinations of the Al/Fe and Mn-Ca/Mg-Ni-Cr options. Preliminary simulant preparation work has already been documented. The four simulants can be used for both high and low noble metal concentration testing and high and low acid testing. This report summarizes preliminary testing of each of the four simulants at low noble metals and low acid stoichiometry. …
Date: December 10, 2009
Creator: Koopman,D. & Lambert, D.
Object Type: Report
System: The UNT Digital Library
TANK 12 SLUDGE CHARACTERIZATION AND ALUMINUM DISSOLUTION DEMONSTRATION (open access)

TANK 12 SLUDGE CHARACTERIZATION AND ALUMINUM DISSOLUTION DEMONSTRATION

A 3-L sludge slurry sample from Tank 12 was characterized and then processed through an aluminum dissolution demonstration. The dominant constituent of the sludge was found to be aluminum in the form of boehmite. The iron content was minor, about one-tenth that of the aluminum. The salt content of the supernatant was relatively high, with a sodium concentration of {approx}7 M. Due to these characteristics, the yield stress and plastic viscosity of the unprocessed slurry were relatively high (19 Pa and 27 cP), and the settling rate of the sludge was relatively low ({approx}20% settling over a two and a half week period). Prior to performing aluminum dissolution, plutonium and gadolinium were added to the slurry to simulate receipt of plutonium waste from H-Canyon. Aluminum dissolution was performed over a 26 day period at a temperature of 65 C. Approximately 60% of the insoluble aluminum dissolved during the demonstration, with the rate of dissolution slowing significantly by the end of the demonstration period. In contrast, approximately 20% of the plutonium and less than 1% of the gadolinium partitioned to the liquid phase. However, about a third of the liquid phase plutonium became solubilized prior to the dissolution period, when the …
Date: March 25, 2009
Creator: Reboul, S; Michael Hay, M; Kristine Zeigler, K & Michael Stone, M
Object Type: Report
System: The UNT Digital Library
Target Talk, Number 146, Spring 2009 (open access)

Target Talk, Number 146, Spring 2009

Newsletter of the Texas Hunter Education Program discussing various events, news, and other information related to the program or of interest to hunters in Texas.
Date: June 2009
Creator: Texas. Parks and Wildlife Department.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Target Talk, Number 147, Summer 2009 (open access)

Target Talk, Number 147, Summer 2009

Newsletter of the Texas Hunter Education Program discussing various events, news, and other information related to the program or of interest to hunters in Texas.
Date: October 2009
Creator: Texas. Parks and Wildlife Department.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Sage-Grouse and Wind Energy: Biology, Habits, and Potential Effects from Development (open access)

Sage-Grouse and Wind Energy: Biology, Habits, and Potential Effects from Development

Proposed development of domestic energy resources, including wind energy, is expected to impact the sagebrush steppe ecosystem in the western United States. The greater sage-grouse relies on habitats within this ecosystem for survival, yet very little is known about how wind energy development may affect sage-grouse. The purpose of this report is to inform organizations of the impacts wind energy development could have on greater sage-grouse populations and identify information needed to fill gaps in knowledge.
Date: July 15, 2009
Creator: Becker, James M.; Tagestad, Jerry D.; Duberstein, Corey A. & Downs, Janelle L.
Object Type: Report
System: The UNT Digital Library
Emergency Communications: The Future of 911 (open access)

Emergency Communications: The Future of 911

This report discusses possible paths toward the modernization of the 911 emergency response system's infrastructure.
Date: January 13, 2009
Creator: Moore, Linda K.
Object Type: Report
System: The UNT Digital Library
Time-dependent amplitude analysis of $B^0 \to K^0_S\pi^ pi^-$ (open access)

Time-dependent amplitude analysis of $B^0 \to K^0_S\pi^ pi^-$

In this paper we present results from a time-dependent amplitude analysis of the B{sup 0} {yields} K{sup 0}{sub s}{pi}{sup +}{pi}{sup -} decay. In Sec. II we describe the time-dependent DP formalism, and introduce the signal parameters that are extracted in the fit to data. In Sec. III we briefly describe the BABAR detector and the data set. In Sec. IV, we explain the selection requirements used to obtain the signal candidates and suppress backgrounds. In Sec. V we describe the fit method and the approach used to control experimental effects such as resolution. In Sec. VI we present the results of the fit, and extract parameters relevant to the contributing intermediate resonant states. In Sec. VII we discuss systematic uncertainties in the results, and finally we summarize the results in Sec. VIII.
Date: May 26, 2009
Creator: Aubert, B.
Object Type: Article
System: The UNT Digital Library
Emergency Communications: The Future of 911 (open access)

Emergency Communications: The Future of 911

Today's 911 system is built on an infrastructure of analog technology that does not support many of the features that most Americans expect are part of an emergency response. Efforts to splice newer, digital technologies onto this aging infrastructure have created points of failure where a call can be dropped or misdirected, sometimes with tragic consequences. This report discusses efforts to modernize and update 911 emergency response technology, the funding for such efforts, and related pieces of legislation.
Date: June 16, 2009
Creator: Moore, Linda K.
Object Type: Report
System: The UNT Digital Library
DWPF CATALYTIC HYDROGEN GENERATION PROGRAM - REVIEW OF CURRENT STATUS (open access)

DWPF CATALYTIC HYDROGEN GENERATION PROGRAM - REVIEW OF CURRENT STATUS

Significant progress has been made in the past two years in improving the understanding of acid consumption and catalytic hydrogen generation during the Defense Waste Processing Facility (DWPF) processing of waste sludges in the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME). This report reviews issues listed in prior internal reviews, describes progress with respect to the recommendations made by the December 2006 external review panel, and presents a summary of the current understanding of catalytic hydrogen generation in the DWPF Chemical Process Cell (CPC). Noble metals, such as Pd, Rh, and Ru, are historically known catalysts for the conversion of formic acid into hydrogen and carbon dioxide. Rh, Ru, and Pd are present in the DWPF SRAT feed as by-products of thermal neutron fission of {sup 235}U in the original waste. Rhodium appears to become most active for hydrogen as the nitrite ion concentration becomes low (within a factor of ten of the Rh concentration). Prior to hydrogen generation, Rh is definitely active for nitrite destruction to N{sub 2}O and potentially active for nitrite to NO formation. These reactions are all consistent with the presence of a nitro-Rh complex catalyst, although definite proof for the existence …
Date: July 10, 2009
Creator: Koopman, D.
Object Type: Report
System: The UNT Digital Library
Emergency Communications: The Future of 911 (open access)

Emergency Communications: The Future of 911

This report discusses possible paths toward the modernization of the 911 emergency response system's infrastructure.
Date: September 28, 2009
Creator: Moore, Linda K.
Object Type: Report
System: The UNT Digital Library
Interim Report to the 81st Texas Legislature: House Committee on Public Education (open access)

Interim Report to the 81st Texas Legislature: House Committee on Public Education

Report from the Texas House Committee on Public Education describing the group's goals, activities, accomplishments, and other information, for review by the 81st Texas Legislature.
Date: January 2009
Creator: Texas. Legislature. House of Representatives. Committee on Public Education.
Object Type: Report
System: The Portal to Texas History
Resolutions of Inquiry: An Analysis of Their Use in the House, 1947-2009 (open access)

Resolutions of Inquiry: An Analysis of Their Use in the House, 1947-2009

This report discusses resolution of inquiry, which is a measure that formally calls on the executive branch to provide specified factual information to Congress.
Date: October 29, 2009
Creator: Davis, Christopher M.
Object Type: Report
System: The UNT Digital Library
Paleontological overview of oil shale and tar sands areas in Colorado, Utah, and Wyoming. (open access)

Paleontological overview of oil shale and tar sands areas in Colorado, Utah, and Wyoming.

In August 2005, the U.S. Congress enacted the Energy Policy Act of 2005, Public Law 109-58. In Section 369 of this Act, also known as the ''Oil Shale, Tar Sands, and Other Strategic Unconventional Fuels Act of 2005,'' Congress declared that oil shale and tar sands (and other unconventional fuels) are strategically important domestic energy resources that should be developed to reduce the nation's growing dependence on oil from politically and economically unstable foreign sources. In addition, Congress declared that both research- and commercial-scale development of oil shale and tar sands should (1) be conducted in an environmentally sound manner using management practices that will minimize potential impacts, (2) occur with an emphasis on sustainability, and (3) benefit the United States while taking into account concerns of the affected states and communities. To support this declaration of policy, Congress directed the Secretary of the Interior to undertake a series of steps, several of which are directly related to the development of a commercial leasing program for oil shale and tar sands. One of these steps was the completion of a programmatic environmental impact statement (PEIS) to analyze the impacts of a commercial leasing program for oil shale and tar sands …
Date: February 11, 2009
Creator: Murphey, P. C.; Daitch, D. & Division, Environmental Science
Object Type: Report
System: The UNT Digital Library
Assessment of the Environmental Impacts of Coalbed Methane Development in the Powder River Basin - Use of Coalbead Methane Produced Water for Cropland Irrigation (open access)

Assessment of the Environmental Impacts of Coalbed Methane Development in the Powder River Basin - Use of Coalbead Methane Produced Water for Cropland Irrigation

Water quality is a major concern with regard to development of coalbed methane (CBM) in the Powder River Basin, Wyoming. Large quantities of water are being produced and discharged as a by-product in the process of releasing natural gas from coal. Current practices of discharging large volumes of water into drainage channels or using it to irrigate cropland areas has the potential to elevate salinity and sodicity in soils. Elevated salinity affects the ability of plants to uptake water to facilitate biochemical processes such as photosynthesis and plant growth. Elevated sodicity in irrigation water adversely affects soil structure necessary for water infiltration, nutrient supply, and aeration. Salinity and sodicity concentrations are important in that a sodic soil can maintain its structure if the salinity level is maintained above the threshold electrolyte concentration. In this study, cropland soil and CBM water were treated with gypsum and sulfur. Changes in soil chemistry among different treatments were monitored using a split plot experiment. The CBM water used for irrigation had an EC of 1380 {micro}S cm{sup -1} and SAR of 24.3 mmol{sup 1/2} L{sup -1/2}. Baseline and post treatment soil samples were collected to a depth of 60 cm within each study plot, …
Date: January 30, 2009
Creator: Morris, Jeff
Object Type: Report
System: The UNT Digital Library
Industrial and Hazardous Waste: Rules and Regulations for Small-Quantity Generators (open access)

Industrial and Hazardous Waste: Rules and Regulations for Small-Quantity Generators

Explanation of industrial and hazardous waste materials and the responsibilities of small-quantity waste generators.
Date: July 2009
Creator: Texas Commission on Environmental Quality
Object Type: Text
System: The Portal to Texas History
Awards of Attorneys’ Fees by Federal Courts and Federal Agencies (open access)

Awards of Attorneys’ Fees by Federal Courts and Federal Agencies

This report contains the awards of attorneys' fees by federal courts and federal agencies. Most Supreme Court decisions involves attorney's fees that have interpreted civil right statutes and this report focuses on these statutes.
Date: July 29, 2009
Creator: Cohen, Henry
Object Type: Report
System: The UNT Digital Library
Speed of Presidential and Senate Actions on Supreme Court Nominations, 1900 - 2009 (open access)

Speed of Presidential and Senate Actions on Supreme Court Nominations, 1900 - 2009

This report provides information on the amount of time taken to act on all Supreme Court nominations occurring between 1900 and the present. It focuses on the actual amounts of time that Presidents and the Senate have taken to act (as opposed to the elapsed time between official points in the process). This report focuses on when the Senate became aware of the President's selection (e.g., via a public announcement by the President).
Date: May 29, 2009
Creator: Garrett, R. Sam & Rutkus, Denis Steven
Object Type: Report
System: The UNT Digital Library
Mixing Cell Model: A One-Dimensional Numerical Model for Assessment of Water Flow and Contaminant Transport in the Unsaturated Zone (open access)

Mixing Cell Model: A One-Dimensional Numerical Model for Assessment of Water Flow and Contaminant Transport in the Unsaturated Zone

This report describes the Mixing Cell Model code, a one-dimensional model for water flow and solute transport in the unsaturated zone under steady-state or transient flow conditions. The model is based on the principles and assumptions underlying mixing cell model formulations. The unsaturated zone is discretized into a series of independent mixing cells. Each cell may have unique hydrologic, lithologic, and sorptive properties. Ordinary differential equations describe the material (water and solute) balance within each cell. Water flow equations are derived from the continuity equation assuming that unit-gradient conditions exist at all times in each cell. Pressure gradients are considered implicitly through model discretization. Unsaturated hydraulic conductivity and moisture contents are determined by the material-specific moisture characteristic curves. Solute transport processes include explicit treatment of advective processes, first-order chain decay, and linear sorption reactions. Dispersion is addressed through implicit and explicit dispersion. Implicit dispersion is an inherent feature of all mixing cell models and originates from the formulation of the problem in terms of mass balance around fully mixed volume elements. Expressions are provided that relate implicit dispersion to the physical dispersion of the system. Two FORTRAN codes were developed to solve the water flow and solute transport equations: (1) …
Date: April 1, 2009
Creator: Rood, A. S.
Object Type: Report
System: The UNT Digital Library
Financial Audit: Federal Deposit Insurance Corporation Funds' 2008 and 2007 Financial Statements (open access)

Financial Audit: Federal Deposit Insurance Corporation Funds' 2008 and 2007 Financial Statements

A letter report issued by the Government Accountability Office with an abstract that begins "GAO is required to annually audit the financial statements of the Deposit Insurance Fund (DIF) and FSLIC Resolution Fund (FRF), which are administered by the Federal Deposit Insurance Corporation (FDIC). GAO is responsible for obtaining reasonable assurance about whether FDIC's financial statements for DIF and FRF are presented fairly in all material respects, in conformity with U.S. generally accepted accounting principles, and whether FDIC maintained effective internal control over financial reporting and compliance with laws and regulations. Also, GAO is responsible for testing FDIC's compliance with selected laws and regulations. Created in 1933 to insure bank deposits and promote sound banking practices, FDIC plays an important role in maintaining public confidence in the nation's financial system. In 1989, legislation to reform the federal deposit insurance system created three funds to be administered by FDIC: the Bank Insurance Fund (BIF) and the Savings Association Insurance Fund (SAIF), which protect bank and savings deposits, and FRF, which was created to close out the business of the former Federal Savings and Loan Insurance Corporation. In accordance with subsequent legislation passed in 2006, FDIC merged the BIF and SAIF into …
Date: May 28, 2009
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library