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Apparatus for real-time acoustic imaging of Rayleigh-Bénard convection (open access)

Apparatus for real-time acoustic imaging of Rayleigh-Bénard convection

We have successfully designed, built and tested an experimental apparatus which is capable of providing the first real-time ultrasound images of Rayleigh-B\'{e}nard convection in optically opaque fluids confined to large aspect ratio experimental cells. The apparatus employs a modified version of a commercially available ultrasound camera to capture images (30 frames per second) of flow patterns in a fluid undergoing Rayleigh Bénard convection. The apparatus was validated by observing convection rolls in 5cSt polydimethylsiloxane (PDMS) polymer fluid. Our first objective, after having built the apparatus, was to use it to study the sequence of transitions from diffusive to time--dependent heat transport in liquid mercury. The aim was to provide important information on pattern formation in the largely unexplored regime of very low Prandtl number fluids. Based on the theoretical stability diagram for liquid mercury, we anticipated that straight rolls should be stable over a range of Rayleigh numbers, between 1708 and approximately 1900. Though some of our power spectral densities were suggestive of the existence of weak convection, we have been unable to unambiguously visualize stable convection rolls above the theoretical onset of convection in liquid mercury. Currently, we are seeking ways to increase the sensitivity of our apparatus, such …
Date: October 28, 2008
Creator: Kuehn, Kerry, K.
System: The UNT Digital Library
Assistance to Firefighters Program: Distribution of Fire Grant Funding (open access)

Assistance to Firefighters Program: Distribution of Fire Grant Funding

This report describes The Assistance to Firefighters Program, specifically assistance to the grant program, grants, and appropriations.
Date: October 28, 2008
Creator: Kruger, Lennard G.
System: The UNT Digital Library
Check 21 Act: Most Consumers Have Accepted and Banks Are Progressing Toward Full Adoption of Check Truncation (open access)

Check 21 Act: Most Consumers Have Accepted and Banks Are Progressing Toward Full Adoption of Check Truncation

A letter report issued by the Government Accountability Office with an abstract that begins "Although check volume has declined, checks still represent a significant volume of payments that need to be processed, cleared, and settled. The Check Clearing for the 21st Century Act of 2003 (Check 21) was intended to make check collection more efficient and less costly by facilitating wider use of electronic check processing. It authorized a new legal instrument--the substitute check--a paper copy of an image of the front and back of the original check. Check 21 facilitated electronic check processing by allowing banks to use electronic imaging technology for collection and create substitute checks from those images for delivery to banks that do not accept checks electronically. Check 21 mandated that GAO evaluate the implementation and administration of the act. The report objectives are to (1) determine the gains in economic efficiency from check truncation and evaluate the benefits and costs to the Federal Reserve System (Federal Reserve) and financial institutions; (2) assess consumer acceptance of the check truncation process resulting from Check 21; and (3) evaluate the benefits and costs to bank consumers from check truncation. GAO analyzed costs for the check operations of the …
Date: October 28, 2008
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
The Controlled Substances Act: Regulatory Requirements (open access)

The Controlled Substances Act: Regulatory Requirements

This report highlights certain non-criminal regulatory requirements of the Controlled Substances Act (CSA).
Date: October 28, 2008
Creator: Nichols, James E. & Yeh, Brian T.
System: The UNT Digital Library
The Convention on the Elimination of All Forms of Discrimination Against Women (CEDAW): Congressional Issues (open access)

The Convention on the Elimination of All Forms of Discrimination Against Women (CEDAW): Congressional Issues

This report provides an overview of the Convention on the Elimination of All Forms of Discrimination Against Women (CEDAW) and describes its background, objectives, and structure, including the role of the Convention's monitoring body, the CEDAW Committee. It examines U.S. policy and issues in the U.S. ratification debate, including the Convention's possible impact on U.S. sovereignty, its effectiveness in combating discrimination, and its role as an instrument of U.S. foreign policy.
Date: October 28, 2008
Creator: Blanchfield, Luisa
System: The UNT Digital Library
Development of a Composite Non-Electrostatic Surface Complexation Model Describing Plutonium Sorption to Aluminosilicates (open access)

Development of a Composite Non-Electrostatic Surface Complexation Model Describing Plutonium Sorption to Aluminosilicates

Due to their ubiquity in nature and chemical reactivity, aluminosilicate minerals play an important role in retarding actinide subsurface migration. However, very few studies have examined Pu interaction with clay minerals in sufficient detail to produce a credible mechanistic model of its behavior. In this work, Pu(IV) and Pu(V) interactions with silica, gibbsite (Aloxide), and Na-montmorillonite (smectite clay) were examined as a function of time and pH. Sorption of Pu(IV) and Pu(V) to gibbsite and silica increased with pH (4 to 10). The Pu(V) sorption edge shifted to lower pH values over time and approached that of Pu(IV). This behavior is apparently due to surface mediated reduction of Pu(V) to Pu(IV). Surface complexation constants describing Pu(IV)/Pu(V) sorption to aluminol and silanol groups were developed from the silica and gibbsite sorption experiments and applied to the montmorillonite dataset. The model provided an acceptable fit to the montmorillonite sorption data for Pu(V). In order to accurately predict Pu(IV) sorption to montmorillonite, the model required inclusion of ion exchange. The objective of this work is to measure the sorption of Pu(IV) and Pu(V) to silica, gibbsite, and smectite (montmorillonite). Aluminosilicate minerals are ubiquitous at the Nevada National Security Site and improving our understanding …
Date: October 28, 2008
Creator: Powell, B. A.; Kersting, A.; Zavarin, M. & Zhao, P.
System: The UNT Digital Library
The Earned Income Tax Credit (EITC): Changes for 2008 and 2009 (open access)

The Earned Income Tax Credit (EITC): Changes for 2008 and 2009

The earned income tax credit established in the tax code in 1975, provides cash assistance to lower-income working parents and individuals through the tax system. The earned income tax credit for some earned income credit recipients will be higher in 2009 than it was in 2008. An increase in the size of the earned income tax credit will occur because the maximum amount of earned income used to calculate the credit and the phase-out income level are indexed for inflation.
Date: October 28, 2008
Creator: Scott, Christine
System: The UNT Digital Library
Fannie Mae and Freddie Mac: Changes to the Regulation of Their Mortgage Portfolios (open access)

Fannie Mae and Freddie Mac: Changes to the Regulation of Their Mortgage Portfolios

This report analyzes the costs and benefits of the Fannie Mae's and Freddie Mac's retained portfolios while they remain under conservatorship.
Date: October 28, 2008
Creator: Weiss, N. Eric
System: The UNT Digital Library
Genetic analysis of the regulation of TCH gene expression, Final Report (open access)

Genetic analysis of the regulation of TCH gene expression, Final Report

The Arabidopsis TCH genes, originally isolated as a consequence of their upregulation in response to the mechanical stimulus of touch, are also upregulated by a variety of seemingly disparate environmental and hormonal stimuli. To gain insight into the complexities of TCH gene regulation, a number of approaches were taken. Regulatory elements responsible for regulation were identified and characteristics of the regulation were evaluated. Reporter genes were used to monitor expression localization and dynamics. Microarray analyses of genome-wide expression behavior indicated that touch-inducible gene expression is more widespread than generally appreciated. Identification of all touch-regulated genes shed light on the types of cellular processes that may be altered in response to mechanical stress perturbations. Expression of the TCH2 gene, also called CML24, encoding a calmodulin (CaM)-like (CML) protein, was evaluated. CML24 shares over 40% amino acid sequence identity with CaM, has 4 EF hands and undergoes a Ca2+-dependent change in migration rate through denaturing gel electrophoresis, indicating that CML24 binds Ca2+ and, as a consequence, undergoes conformational changes. CML24 expression occurs in all major organs and is induced from 2- to 15-fold in plants subjected to touch, darkness, heat, cold, hydrogen peroxide, abscisic acid (ABA) and indole-3-acetic acid. The putative CML24 …
Date: October 28, 2008
Creator: Braam, Janet
System: The UNT Digital Library
Iraq: Post-Saddam Governance and Security (open access)

Iraq: Post-Saddam Governance and Security

None
Date: October 28, 2008
Creator: unknown
System: The UNT Digital Library
Modeling Protein Structures with Conditional Random Fields: Final Report (open access)

Modeling Protein Structures with Conditional Random Fields: Final Report

This document is the final report for DE-FG02-05ER25696. It describes the results of the performed research.
Date: October 28, 2008
Creator: Langmead, Christopher
System: The UNT Digital Library
Operation Iraqi Freedom: Strategies, Approaches, Results, and Issues for Congress (open access)

Operation Iraqi Freedom: Strategies, Approaches, Results, and Issues for Congress

None
Date: October 28, 2008
Creator: unknown
System: The UNT Digital Library
RANGE AND DISTRIBUTION OF TECHNETIUM KD VALUES IN THE SRS SUBSURFACE ENVIRONMENT (open access)

RANGE AND DISTRIBUTION OF TECHNETIUM KD VALUES IN THE SRS SUBSURFACE ENVIRONMENT

Performance assessments (PAs) are risk calculations used to estimate the amount of low-level radioactive waste that can be disposed at DOE sites. Distribution coefficients (K{sub d} values) are input parameters used in PA calculations to provide a measure of radionuclide sorption to sediment; the greater the K{sub d} value, the greater the sorption and the slower the estimated movement of the radionuclide through sediment. Understanding and quantifying K{sub d} value variability is important for estimating the uncertainty of PA calculations. Without this information, it is necessary to make overly conservative estimates about the possible limits of K{sub d} values, which in turn may increase disposal costs. Finally, technetium is commonly found to be amongst the radionuclides posing potential risk at waste disposal locations because it is believed to be highly mobile in its anionic form (pertechnetate, TcO{sub 4}{sup -}), it exists in relatively high concentrations in SRS waste, and it has a long half-life (213,000 years). The objectives of this laboratory study were to determine under SRS environmental conditions: (1) whether and to what extent TcO{sub 4}{sup -} sorbs to sediments, (2) the range of Tc K{sub d} values, (3) the distribution (normal or log-normal) of Tc K{sub d} values, …
Date: October 28, 2008
Creator: Kaplan, D
System: The UNT Digital Library
Recreation on Federal Lands (open access)

Recreation on Federal Lands

None
Date: October 28, 2008
Creator: unknown
System: The UNT Digital Library
Remaining Sites Verification Package for the 600-111, P-11 Critical Mass Laboratory Crib, and UPR-600-16, Fire and Contamination Spread Waste Sites, Waste Site Reclassification Form 2004-065 (open access)

Remaining Sites Verification Package for the 600-111, P-11 Critical Mass Laboratory Crib, and UPR-600-16, Fire and Contamination Spread Waste Sites, Waste Site Reclassification Form 2004-065

The 600-111, P-11 Critical Mass Laboratory Crib waste site, also referred to as the P-11 Facility, included the 120 Experimental Building, the 123 Control Building, and the P-11 Crib. The facility was constructed in 1949 and was used as a laboratory for plutonium criticality studies. In accordance with this evaluation, the confirmatory and verification sampling results support a reclassification of this site to Interim Closed Out. The results of confirmatory and verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.
Date: October 28, 2008
Creator: Capron, J. M.
System: The UNT Digital Library
Remaining Sites Verification Package for the 600-111, P-11 Critical Mass Laboratory Crib, and UPR-600-16, Fire and Contamination Spread Waste Sites, Waste Site Reclassification Form 2008-045 (open access)

Remaining Sites Verification Package for the 600-111, P-11 Critical Mass Laboratory Crib, and UPR-600-16, Fire and Contamination Spread Waste Sites, Waste Site Reclassification Form 2008-045

The UPR-600-16, Fire and Contamination Spread waste site is an unplanned release that occurred on December 4, 1951, when plutonium contamination was spread by a fire that ignited inside the 120 Experimental Building. The 120 Experimental Building was a laboratory building that was constructed in 1949 and used for plutonium criticality studies as part of the P-11 Project. In November 1951, a criticality occurred in the 120 Experimental Building that resulted in extensive plutonium contamination inside the building. The confirmatory evaluation supports a reclassification of this site to Interim Closed Out. The current site conditions achieve the remedial action objectives and the corresponding remedial action goals established in the Remaining Sites ROD. The results of the extensive radiological survey of the surface soil and the confirmatory and verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.
Date: October 28, 2008
Creator: Capron, J. M.
System: The UNT Digital Library
Retirement Benefits for Members of Congress (open access)

Retirement Benefits for Members of Congress

This report discusses the Civil Service Retirement Act of 1920 (P.L. 66-215) that established a pension system for federal employees in the executive branch of government.
Date: October 28, 2008
Creator: Purcell, Patrick
System: The UNT Digital Library
SODIUM ALUMINOSILICATE FOULING AND CLEANING OF DECONTAMINATED SALT SOLUTION COALESCERS (open access)

SODIUM ALUMINOSILICATE FOULING AND CLEANING OF DECONTAMINATED SALT SOLUTION COALESCERS

During initial non-radioactive operations at the Modular Caustic Side Solvent Extraction Unit (MCU), the pressure drop across the decontaminated salt solution coalescer reached {approx}10 psi while processing {approx}1250 gallons of salt solution, indicating possible fouling or plugging of the coalescer. An analysis of the feed solution and the 'plugged coalescer' concluded that the plugging was due to sodium aluminosilicate solids. MCU personnel requested Savannah River National Laboratory (SRNL) to investigate the formation of the sodium aluminosilicate solids (NAS) and the impact of the solids on the decontaminated salt solution coalescer. Researchers performed developmental testing of the cleaning protocols with a bench-scale coalescer container 1-inch long segments of a new coalescer element fouled using simulant solution. In addition, the authors obtained a 'plugged' Decontaminated Salt Solution coalescer from non-radioactive testing in the MCU and cleaned it according to the proposed cleaning procedure. Conclusions from this testing include the following: (1) Testing with the bench-scale coalescer showed an increase in pressure drop from solid particles, but the increase was not as large as observed at MCU. (2) Cleaning the bench-scale coalescer with nitric acid reduced the pressure drop and removed a large amount of solid particles (11 g of bayerite if all …
Date: October 28, 2008
Creator: Poirier, M; Thomas Peters, T; Fernando Fondeur, F & Samuel Fink, S
System: The UNT Digital Library
The Specialty Metal Provision and the Berry Amendment: Issues for Congress (open access)

The Specialty Metal Provision and the Berry Amendment: Issues for Congress

This report examines the specialty metal provision which was originally part of the Berry Amendment, the potential oversight issues for Congress, and options that Congress may wish to consider.
Date: October 28, 2008
Creator: Bailey Grasso, Valerie
System: The UNT Digital Library
The U.S. Commission on Civil Rights: History, Funding, and Current Issues (open access)

The U.S. Commission on Civil Rights: History, Funding, and Current Issues

None
Date: October 28, 2008
Creator: Laney, Garrine P.
System: The UNT Digital Library
U.S. Trade and Investment Relationship with Sub-Saharan Africa: The African Growth and Opportunity Act and Beyond (open access)

U.S. Trade and Investment Relationship with Sub-Saharan Africa: The African Growth and Opportunity Act and Beyond

This report presents perspectives on African economic trends and provides an overview of U.S. trade and investment flows with sub-Saharan Africa (SSA). It discusses the provisions of the African Growth and Opportunity Act (AGOA) and the changes that have occurred since its enactment. It concludes with a brief discussion of issues of congressional interest.
Date: October 28, 2008
Creator: Langton, Danielle
System: The UNT Digital Library