Ambient-temperature Conditioning as a Probe of Double-C Transformation Mechanisms in Pu-2.0 at. % Ga (open access)

Ambient-temperature Conditioning as a Probe of Double-C Transformation Mechanisms in Pu-2.0 at. % Ga

The gallium-stabilized Pu-2.0 at. % Ga alloy undergoes a partial or incomplete low-temperature martensitic transformation from the metastable {delta} phase to the gallium-containing, monoclinic {alpha}{prime} phase near -100 C. This transformation has been shown to occur isothermally and it displays anomalous double-C kinetics in a time-temperature-transformation (TTT) diagram, where two nose temperatures anchoring an upper- and lower-C describe minima in the time for the initiation of transformation. The underlying mechanisms responsible for the double-C behavior are currently unresolved, although recent experiments suggest that a conditioning treatment--wherein, following an anneal at 375 C, the sample is held at a sub-anneal temperature for a period of time--significantly influences the upper-C of the TTT diagram. As such, elucidating the effects of the conditioning treatment upon the {delta} {yields} {alpha}{prime} transformation can provide valuable insights into the fundamental mechanisms governing the double-C kinetics of the transition. Following a high-temperature anneal, a differential scanning calorimeter (DSC) was used to establish an optimal conditioning curve that depicts the amount of {alpha}{prime} formed during the transformation as a function of conditioning temperature for a specified time. With the optimal conditioning curve as a baseline, the DSC was used to explore the circumstances under which the effects of …
Date: April 2, 2008
Creator: Jeffries, J R; Blobaum, K M; Wall, M A & Schwartz, A J
Object Type: Article
System: The UNT Digital Library
Aquifer Testing Recommendations for Supporting Phase II of the T Area Technetium-99 Data Objectives Process (open access)

Aquifer Testing Recommendations for Supporting Phase II of the T Area Technetium-99 Data Objectives Process

Aquifer characterization needs are currently being assessed to optimize pump-and-treat remedial strategies within the 200-ZP-1 operable unit, specifically for the immediate area of the 241-T Tank Farm. This report provides a general discussion of the six identified hydrologic test methods for possible subsequent characterization within the 241-T Tank Farm area and details for implementing the large-scale recovery test after terminating pumping at the 241-Tank Farm extraction well locations.
Date: April 2, 2008
Creator: Spane, Frank A.
Object Type: Report
System: The UNT Digital Library
ARCHITECTURE OF A CHARGE-TRANSFER STATE REGULATING LIGHT HARVESTING IN A PLANT ANTENNA PROTEIN (open access)

ARCHITECTURE OF A CHARGE-TRANSFER STATE REGULATING LIGHT HARVESTING IN A PLANT ANTENNA PROTEIN

Energy-dependent quenching of excess absorbed light energy (qE) is a vital mechanism for regulating photosynthetic light harvesting in higher plants. All of the physiological characteristics of qE have been positively correlated with charge-transfer between coupled chlorophyll and zeaxanthin molecules in the light-harvesting antenna of photosystem II (PSII). In this work, we present evidence for charge-transfer quenching in all three of the individual minor antenna complexes of PSII (CP29, CP26, and CP24), and we conclude that charge-transfer quenching in CP29 involves a de-localized state of an excitonically coupled chlorophyll dimer. We propose that reversible conformational changes in CP29 can `tune? the electronic coupling between the chlorophylls in this dimer, thereby modulating the energy of the chlorophylls-zeaxanthin charge-transfer state and switching on and off the charge-transfer quenching during qE.
Date: April 2, 2008
Creator: Fleming, Graham; Ahn, Tae Kyu; Avenson, Thomas J.; Ballottari, Matteo; Cheng, Yuan-Chung; Niyogi, Krishna K. et al.
Object Type: Article
System: The UNT Digital Library
The Army Corps of Engineers’ Nationwide Permits Program: Issues and Regulatory Developments (open access)

The Army Corps of Engineers’ Nationwide Permits Program: Issues and Regulatory Developments

This report contains the issues and regulatory developments of the Army Corps of engineers' nationwide permits program.
Date: April 2, 2008
Creator: Copeland, Claudia
Object Type: Report
System: The UNT Digital Library
Caution -- Beam Crossing Ahead (open access)

Caution -- Beam Crossing Ahead

There are times when a laser beam needs to cross between tables or even go from one room to another. This presents an interesting traffic-flow and safety challenge to both the laser safety officer and laser user. Fortunately it is a challenge that has several solutions But the simplest solution may not be the best one. For example, the simplest way to get a beam from one optical table to another is just to put a sturdy tube around it. That's a permanent solution, and it completely contains the laser beam. While this is laser safe, there can be egress issues if it blocks a walkway. One comment this author often hears is, 'We can just duck under the tube.' The fire marshal, as well as the laser safety officer, might have issues with this. Especially in the case of a darkened lab, a blocked walkway can present a hazard of its own. One good solution is to transport the beam from Point A to Point B through a fiberoptic cable, when that is possible. One should easily be able to run the fiber up and over any walkway or down through a conduit on the floor. An important concern …
Date: April 2, 2008
Creator: Barat, Kenneth L.
Object Type: Article
System: The UNT Digital Library
Chemical Kinetic Modeling of Hydrogen Combustion Limits (open access)

Chemical Kinetic Modeling of Hydrogen Combustion Limits

A detailed chemical kinetic model is used to explore the flammability and detonability of hydrogen mixtures. In the case of flammability, a detailed chemical kinetic mechanism for hydrogen is coupled to the CHEMKIN Premix code to compute premixed, laminar flame speeds. The detailed chemical kinetic model reproduces flame speeds in the literature over a range of equivalence ratios, pressures and reactant temperatures. A series of calculation were performed to assess the key parameters determining the flammability of hydrogen mixtures. Increased reactant temperature was found to greatly increase the flame speed and the flammability of the mixture. The effect of added diluents was assessed. Addition of water and carbon dioxide were found to reduce the flame speed and thus the flammability of a hydrogen mixture approximately equally well and much more than the addition of nitrogen. The detailed chemical kinetic model was used to explore the detonability of hydrogen mixtures. A Zeldovich-von Neumann-Doring (ZND) detonation model coupled with detailed chemical kinetics was used to model the detonation. The effectiveness on different diluents was assessed in reducing the detonability of a hydrogen mixture. Carbon dioxide was found to be most effective in reducing the detonability followed by water and nitrogen. The chemical …
Date: April 2, 2008
Creator: Pitz, W J & Westbrook, C K
Object Type: Report
System: The UNT Digital Library
Cosmic Ray Results From the CosmoALEPH Experiment (open access)

Cosmic Ray Results From the CosmoALEPH Experiment

None
Date: April 2, 2008
Creator: Grupen, C.; Hashim, N. -O.; Jost, B.; Maciuc, F.; Luitz, S.; Mailov, A. et al.
Object Type: Article
System: The UNT Digital Library
Critical Infrastructures: Background, Policy, and Implementation (open access)

Critical Infrastructures: Background, Policy, and Implementation

None
Date: April 2, 2008
Creator: Moteff, John D.
Object Type: Report
System: The UNT Digital Library
Defense Critical Infrastructure: DOD's Risk Analysis of Its Critical Infrastructure Omits Highly Sensitive Assets (open access)

Defense Critical Infrastructure: DOD's Risk Analysis of Its Critical Infrastructure Omits Highly Sensitive Assets

Correspondence issued by the Government Accountability Office with an abstract that begins "The Department of Defense (DOD) relies on a global network of critical physical and cyber infrastructure to project, support, and sustain its forces and operations worldwide. The incapacitation, exploitation, or destruction of one or more of its assets would seriously damage DOD's ability to carry out its core missions. To identify and help assure the availability of this mission-critical infrastructure, in August 2005, DOD established the Defense Critical Infrastructure Program (DCIP), assigning overall responsibility for the program to the Assistant Secretary of Defense for Homeland Defense and Americas' Security Affairs (ASD[HD&ASA]). Since 2006, ASD(HD&ASA) has collaborated with the Joint Staff to compile a list of all DOD- and non-DOD-owned infrastructure essential to accomplish the National Defense Strategy. Each critical asset on the list must undergo a vulnerability assessment, which identifies weaknesses in relation to potential threats and suggests options to address those weaknesses. Data and material designated as Sensitive Compartmented Information (SCI) or associated with Special Access Programs (SAP) are among the nation's most valued and closely guarded assets, and DOD faces inherent challenges in incorporating them into DCIP. The number of individuals authorized to access SCI and …
Date: April 2, 2008
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Design of Current Leads for the MICE Coupling Magnet (open access)

Design of Current Leads for the MICE Coupling Magnet

A pair of superconducting coupling magnets will be part of the Muon Ionization Cooling Experiment (MICE). They were designed and will be constructed by the Institute of Cryogenics and Superconductivity Technology, Harbin Institute of Technology, in collaboration with Lawrence Berkeley National Laboratory. The coupling magnet is to be cooled by using cryocoolers at 4.2K. In order to reduce the heat leak to the 4.2K cold mass from 300 K, a pair of current leads composed of conventional copper leads and high temperature superconductor (HTS) leads will be used to supply current to the magnet. This paper presents the optimization of the conventional conduction-cooled metal leads for the coupling magnet. Analyses on heat transfer down the leads using theoretical method and numerical simulation were carried out. The stray magnetic field around the HTS leads has been calculated and effects of the magnetic field on the performance of the HTS leads has also been analyzed.
Date: April 2, 2008
Creator: Wang, Li; Li, L.K.; Wu, Hong; Xu, Feng Yu; Liu, X.K.; Jia, Lin X. et al.
Object Type: Article
System: The UNT Digital Library
Disaster Debris Removal After Hurricane Katrina: Status and Associated Issues (open access)

Disaster Debris Removal After Hurricane Katrina: Status and Associated Issues

This report provides information about the Status and Associated Issues of Disaster Debris Removal After Hurricane Katrina.Hurricane Katrina produced unprecedented destruction resulting in disaster debris from man-made structures.
Date: April 2, 2008
Creator: Luther, Linda
Object Type: Report
System: The UNT Digital Library
Fast Implementation of Matched Filter Based Automatic Alignment Image Processing (open access)

Fast Implementation of Matched Filter Based Automatic Alignment Image Processing

Video images of laser beams imprinted with distinguishable features are used for alignment of 192 laser beams at the National Ignition Facility (NIF). Algorithms designed to determine the position of these beams enable the control system to perform the task of alignment. Centroiding is a common approach used for determining the position of beams. However, real world beam images suffer from intensity fluctuation or other distortions which make such an approach susceptible to higher position measurement variability. Matched filtering used for identifying the beam position results in greater stability of position measurement compared to that obtained using the centroiding technique. However, this gain is achieved at the expense of extra processing time required for each beam image. In this work we explore the possibility of using a field programmable logic array (FPGA) to speed up these computations. The results indicate a performance improvement of 20 using the FPGA relative to a 3 GHz Pentium 4 processor.
Date: April 2, 2008
Creator: Awwal, A. S.; Rice, K. & Taha, T.
Object Type: Article
System: The UNT Digital Library
Federal Advisory Committee Act: Issues Related to the Independence and Balance of Advisory Committees (open access)

Federal Advisory Committee Act: Issues Related to the Independence and Balance of Advisory Committees

Testimony issued by the Government Accountability Office with an abstract that begins "Because advisory committees provide input to federal decision makers on significant national issues, it is essential that their membership be, and be perceived as being, free from conflicts of interest and balanced as a whole. The Federal Advisory Committee Act (FACA) was enacted in 1972, in part, because of concerns that special interests had too much influence over federal agency decision makers. The General Services Administration (GSA) develops guidance on establishing and managing FACA committees. The Office of Government Ethics (OGE) develops regulations and guidance for statutory conflict-of- interest provisions that apply to some advisory committee members. As requested, this testimony discusses key findings and conclusions in our 2004 report, Federal Advisory Committees: Additional Guidance Could Help Agencies Better Ensure Independence and Balance; GAO's recommendations to GSA and OGE and their responses; and potential changes to FACA that could better ensure the independence and balance of advisory committees. For our 2004 work, we reviewed policies and procedures issued by GSA, OGE, and nine federal agencies that sponsor many committees. For this testimony, we obtained information from GSA and OGE on actions they have taken to implement our recommendations; …
Date: April 2, 2008
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Filling the Amendment Tree in the Senate (open access)

Filling the Amendment Tree in the Senate

None
Date: April 2, 2008
Creator: Davis, Christopher M.
Object Type: Report
System: The UNT Digital Library

Fuel Cell Vehicle Learning Demonstration: Spring 2008 Results

Presentation prepared for the 2008 National Hydrogen Association Conference that describes the spring 2008 results for DOE's Fuel Cell Vehicle Learning Demonstration.
Date: April 2, 2008
Creator: Wipke, K.; Sprik, S.; Kurtz, J. & Garbak, J.
Object Type: Presentation
System: The UNT Digital Library
Global HIV/AIDS: A More Country-Based Approach Could Improve Allocation of PEPFAR Funding (open access)

Global HIV/AIDS: A More Country-Based Approach Could Improve Allocation of PEPFAR Funding

A letter report issued by the Government Accountability Office with an abstract that begins "The President's Emergency Plan for AIDS Relief (PEPFAR) provides assistance for combating HIV/AIDS in 15 focus countries and elsewhere, with global targets for prevention, treatment, and care. The U.S. Leadership Against HIV/AIDS, TB and Malaria Act of 2003, which authorizes the $15 billion program, contains directives to guide the Office of the U.S. Global AIDS Coordinator's (OGAC) allocation of this funding. The act expires in September 2008. The President announced his intention to ask Congress to authorize $30 billion for these efforts for the next 5 years. In 2007, the Institute of Medicine (IOM) recommended eliminating the directives. GAO was asked to describe (1) the views of HIV/AIDS experts on these directives, (2) an alternative approach to allocating funds, and (3) potential challenges related to this approach. GAO interviewed 22 experts, surveyed PEPFAR officials in the 15 focus countries, and reviewed pertinent documentation."
Date: April 2, 2008
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Global HIV/AIDS: Survey of PEPFAR Country Team Officials (GAO-08-534SP), an E-supplement to GAO-08-480 (open access)

Global HIV/AIDS: Survey of PEPFAR Country Team Officials (GAO-08-534SP), an E-supplement to GAO-08-480

Other written product issued by the Government Accountability Office with an abstract that begins "This is the E-supplement to GAO-08-480. This document presents the results of our electronic survey of 41 U.S. officials implementing PEPFAR funding in 15 focus countries (country team officials). We conducted the survey to identify potential challenges to implementing an alternative approach, developed from HIV/AIDS experts' suggestions, to allocating funds for the next 5-year phase of PEPFAR. The survey respondents included the Centers for Disease Control and Prevention (CDC) Chief of Party, the U.S. Agency for International Development (USAID) health team leader, and the PEPFAR coordinator in each of the 15 focus countries. The questions in our survey were intended to obtain information on country teams' experiences with setting targets, selecting interventions, and using cost information. Of the 41 country team officials, 38 responded to the survey, resulting in a survey response rate of 93 percent. This document presents results from all closed-ended survey questions but does not include narrative responses that we received. A more detailed discussion of our scope and methodology is contained in our report Global HIV/AIDS: A More Country-Based Approach Could Improve Allocation of PEPFAR Funding (GAO-08-480). We administered the survey from …
Date: April 2, 2008
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Iraq: Oil and Gas Legislation, Revenue Sharing, and U.S. Policy (open access)

Iraq: Oil and Gas Legislation, Revenue Sharing, and U.S. Policy

This report reviews the package of legislation currently under consideration, analyzes the positions of various Iraqi political actors, and discusses potential implications for U.S. foreign policy goals in Iraq.
Date: April 2, 2008
Creator: Blanchard, Christopher M.
Object Type: Report
System: The UNT Digital Library
Low-Cost High-Pressure Hydrogen Generator (open access)

Low-Cost High-Pressure Hydrogen Generator

Electrolysis of water, particularly in conjunction with renewable energy sources, is potentially a cost-effective and environmentally friendly method of producing hydrogen at dispersed forecourt sites, such as automotive fueling stations. The primary feedstock for an electrolyzer is electricity, which could be produced by renewable sources such as wind or solar that do not produce carbon dioxide or other greenhouse gas emissions. However, state-of-the-art electrolyzer systems are not economically competitive for forecourt hydrogen production due to their high capital and operating costs, particularly the cost of the electricity used by the electrolyzer stack. In this project, Giner Electrochemical Systems, LLC (GES) developed a low cost, high efficiency proton-exchange membrane (PEM) electrolysis system for hydrogen production at moderate pressure (300 to 400 psig). The electrolyzer stack operates at differential pressure, with hydrogen produced at moderate pressure while oxygen is evolved at near-atmospheric pressure, reducing the cost of the water feed and oxygen handling subsystems. The project included basic research on catalysts and membranes to improve the efficiency of the electrolysis reaction as well as development of advanced materials and component fabrication methods to reduce the capital cost of the electrolyzer stack and system. The project culminated in delivery of a prototype electrolyzer …
Date: April 2, 2008
Creator: Cropley, Cecelia C. & Norman, Timothy J.
Object Type: Report
System: The UNT Digital Library
Medicaid Rehabilitation Services (open access)

Medicaid Rehabilitation Services

None
Date: April 2, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Polo-like Kinase I is involved in Invasion through Extracellular Matrix (open access)

Polo-like Kinase I is involved in Invasion through Extracellular Matrix

Polo-like kinase 1, PLK1, has important functions in maintaining genome stability and is involved in regulation of mitosis. PLK1 is up regulated in many invasive carcinomas. We asked whether it may also play a role in acquisition of invasiveness, a crucial step in transition to malignancy. In a model of metaplastic basal-like breast carcinoma progression, we found that PLK1 expression is necessary but not sufficient to induce invasiveness through laminin-rich extracellular matrix. PLK1 mediates invasion via Vimentin and {beta}1 integrin, both of which are necessary. We observed that PLK1 phosphorylates Vimentin on serine 82, which in turn regulates cell surface levels of {beta}1 integrin. We found PLK1 to be also highly expressed in pre-invasive in situ carcinomas of the breast. These results support a role for the involvement of PLK1 in the invasion process and point to this pathway as a potential therapeutic target for pre-invasive and invasive breast carcinoma treatment.
Date: April 2, 2008
Creator: Bissell, Mina J; Rizki, Aylin; Mott, Joni D. & Bissell, Mina J
Object Type: Article
System: The UNT Digital Library
Preparation of Size-tunable, Highly Monodisperse PVP-Protected Pt-nanoparticles by Seed-mediated Growth (open access)

Preparation of Size-tunable, Highly Monodisperse PVP-Protected Pt-nanoparticles by Seed-mediated Growth

We demonstrate a preparative method which produces highly-monodisperse Pt-nanoparticles of tunable size without the external addition of seed particles. Hexachloroplatinic acid is dosed slowly to an ethylene glycol solution at 120 C and reduced in the presence of a stabilizing polymer poly-N-vinylpyrollidone (PVP). Slow addition of the Pt-salt first will first lead to the formation of nuclei (seeds) which then grow further to produce larger particles of any desired size between 3 and 8nm. The amount of added hexachloroplatinic acid precursor controls the size of the final nanoparticle product. TEM was used to determine size and morphology and to confirm the crystalline nature of the nanoparticles. Good reproducibility of the technique was demonstrated. Above 7nm, the particle shape and morphology changes suddenly indicating a change in the deposition selectivity of the Pt-precursor from (100) towards (111) crystal faces and breaking up of larger particles into smaller entities.
Date: April 2, 2008
Creator: Koebel, Matthias Michael; Jones, Louis C. & Somorjai, Gabor A.
Object Type: Article
System: The UNT Digital Library
The President Pro Tempore of the Senate: History and Authority of the Office (open access)

The President Pro Tempore of the Senate: History and Authority of the Office

None
Date: April 2, 2008
Creator: Davis, Christopher M.
Object Type: Report
System: The UNT Digital Library
A Single-band Cold Mass Support System for the MICE Superconducting Coupling Magnet (open access)

A Single-band Cold Mass Support System for the MICE Superconducting Coupling Magnet

The cooling channel of the Muon Ionization Cooling Experiment (MICE) consists of eighteen superconducting solenoid coils, which are magnetically hooked together and contained in seven modules. The operations of a pair of MICE superconducting coupling magnets are affected directly by the other solenoid coils in the MICE channel. In order to meet the stringent requirement for the magnet center and axis azimuthal angle at 4.2 K, a self-centered tension-band cold mass support system with intermediate thermal interruption was applied for the MICE superconducting coupling magnet. The physical center of the magnet does not change as it is cooled down from 300 K to 4.2 K using this support system. This paper analyzed and calculated force loads on the coupling magnet under various operation modes of the MICE cooling channel. The performance parameters of a single-band cold mass support system were calculated also.
Date: April 2, 2008
Creator: Wu, Hong; Wang, Li; Liu, X.K.; Liu, C.S.; Li, L.K.; Xu, Feng Yu et al.
Object Type: Article
System: The UNT Digital Library