Tomographic Imaging of Water Injection and Withdrawal in PEMFC Gas Diffusion Layers (open access)

Tomographic Imaging of Water Injection and Withdrawal in PEMFC Gas Diffusion Layers

X-ray computed tomography was used to visualize the water configurations inside gas diffusion layers for various applied capillary pressures, corresponding to both water invasion and withdrawal. A specialized sample holder was developed to allow capillary pressure control on the small-scale samples required. Tests were performed on GDL specimens with and without hydrophobic treatments.
Date: June 25, 2010
Creator: McGill University
Object Type: Article
System: The UNT Digital Library
Construction of a Novel Tabletop X-Ray Generator (open access)

Construction of a Novel Tabletop X-Ray Generator

None
Date: August 25, 2010
Creator: Hostetter, James & /SLAC, /Louisiana State U.
Object Type: Report
System: The UNT Digital Library
Holbrook Substation Superconductor Cable System, Long Island, New York Final Report (open access)

Holbrook Substation Superconductor Cable System, Long Island, New York Final Report

The LIPA Superconductor project broke ground on July 4, 2006, was first energized on April 22, 2008 (Earth Day) and was commissioned on June 25, 2008. Since commissioning, up until early March, 2009, there were numerous refrigeration events that impacted steady state operations. This led to the review of the alarms that were being generated and a rewrite of the program logic in order to decrease the hypersensitivity surrounding these alarms. The high temperature superconductor (HTS) cable was energized on March 5, 2009 and ran uninterrupted until a human error during a refrigeration system switchover knocked the cable out of the grid in early February 2010. The HTS cable was in the grid uninterrupted from March 5, 2009 to February 4, 2010. Although there have been refrigeration events (propagated mainly by voltage sags/surges) during this period, the system was able to automatically switch over from the primary to the backup refrigeration system without issue as required during this period. On February 4, 2010, when switching from the backup over to the primary refrigeration system, two rather than one liquid nitrogen pumps were started inadvertently by a human error (communication) causing an overpressure in the cable cooling line. This in turn …
Date: June 25, 2010
Creator: Maguire, James & McNamara, Joseph
Object Type: Report
System: The UNT Digital Library
Bragg Experimental SensorNet Testbed (BEST) (open access)

Bragg Experimental SensorNet Testbed (BEST)

The principal causative objectives of BEST were to consolidate the 9-1-1 and emergency response services into an Integrated Incident Management Center (I2MC) and to establish an 'Interoperability framework' based on SensorNet protocols to allow additional components to be added to the I2MC over time.
Date: January 25, 2010
Creator: Gorman, Bryan
Object Type: Report
System: The UNT Digital Library
A luminescent nanocrystal stress gauge (open access)

A luminescent nanocrystal stress gauge

Microscale mechanical forces can determine important outcomes ranging from the site of material fracture to stem cell fate. However, local stresses in a vast majority of systems cannot be measured due to the limitations of current techniques. In this work, we present the design and implementation of the CdSe/CdS core/shell tetrapod nanocrystal, a local stress sensor with bright luminescence readout. We calibrate the tetrapod luminescence response to stress, and use the luminescence signal to report the spatial distribution of local stresses in single polyester fibers under uniaxial strain. The bright stress-dependent emission of the tetrapod, its nanoscale size, and its colloidal nature provide a unique tool that may be incorporated into a variety of micromechanical systems including materials and biological samples to quantify local stresses with high spatial resolution.
Date: October 25, 2010
Creator: Choi, Charina; Koski, Kristie; Olson, Andrew & Alivisatos, Paul
Object Type: Article
System: The UNT Digital Library
2010 INORGANIC CHEMISTRY GORDON RESEARCH CONFERENCE JUNE 20 - 25, 2010 (open access)

2010 INORGANIC CHEMISTRY GORDON RESEARCH CONFERENCE JUNE 20 - 25, 2010

The Inorganic Chemistry GRC is one of the longest-standing of the GRCs, originating in 1951. Over the years, this conference has played a role in spawning many other GRCs in specialized fields, due to the involvement of elements from most of the periodic table. These include coordination, organometallic, main group, f-element, and solid state chemistries; materials science, catalysis, computational chemistry, nanotechnology, bioinorganic, environmental, and biomedical sciences just to name a few. The 2010 Inorganic Chemistry GRC will continue this tradition, where scientists at all levels from academic, industrial, and national laboratories meet to define the important problems in the field and to highlight emerging opportunities through exchange of ideas and discussion of unpublished results. Invited speakers will present on a wide variety of topics, giving attendees a look at areas both inside and outside of their specialized areas of interest. In addition to invited speakers, the poster sessions at GRCs are a key feature of the conference. All conferees at the Inorganic Chemistry GRC are invited to present a poster on their work, and here the informal setting promotes the free exchange of ideas and fosters new relationships. As in previous years, we will offer poster presenters the opportunity to …
Date: June 25, 2010
Creator: LOCKEMEYER, JOHN
Object Type: Article
System: The UNT Digital Library
ANSI/ASHRAE/IESNA Standard 90.1-2007 Preliminary Qualitative Determination (open access)

ANSI/ASHRAE/IESNA Standard 90.1-2007 Preliminary Qualitative Determination

A preliminary qualitative analysis of all addenda to ANSI/ASHRAE/IESNA Standard 90.1-2004 that were included in ANSI/ASHRAE/IESNA Standard 90.1-2007 was conducted. All 44 addenda processed by ASHRAE in the creation of Standard 90.1-2007 from Standard 90.1-2004 were evaluated by DOE for their impact on energy efficiency. DOE preliminarily determined whether that addenda would have a positive, neutral, or negative impact on overall building efficiency.
Date: May 25, 2010
Creator: Halverson, Mark A.; Liu, Bing; Richman, Eric E. & Winiarski, David W.
Object Type: Report
System: The UNT Digital Library
Physical Properties of Hanford Transuranic Waste (open access)

Physical Properties of Hanford Transuranic Waste

The research described herein was undertaken to provide needed physical property descriptions of the Hanford transuranic tank sludges under conditions that might exist during retrieval, treatment, packaging and transportation for disposal. The work addressed the development of a fundamental understanding of the types of systems represented by these sludge suspensions through correlation of the macroscopic rheological properties with particle interactions occurring at the colloidal scale in the various liquid media. The results of the work have advanced existing understanding of the sedimentation and aggregation properties of complex colloidal suspensions. Bench scale models were investigated with respect to their structural, colloidal and rheological properties that should be useful for the development and optimization of techniques to process the wastes at various DOE sites.
Date: March 25, 2010
Creator: Berg, John C.
Object Type: Report
System: The UNT Digital Library
CREATION OF THE MODEL ADDITIONAL PROTOCOL (open access)

CREATION OF THE MODEL ADDITIONAL PROTOCOL

In 1991, the international nuclear nonproliferation community was dismayed to discover that the implementation of safeguards by the International Atomic Energy Agency (IAEA) under its NPT INFCIRC/153 safeguards agreement with Iraq had failed to detect Iraq's nuclear weapon program. It was now clear that ensuring that states were fulfilling their obligations under the NPT would require not just detecting diversion but also the ability to detect undeclared materials and activities. To achieve this, the IAEA initiated what would turn out to be a five-year effort to reappraise the NPT safeguards system. The effort engaged the IAEA and its Member States and led to agreement in 1997 on a new safeguards agreement, the Model Protocol Additional to the Agreement(s) between States and the International Atomic Energy Agency for the Application of Safeguards. The Model Protocol makes explicit that one IAEA goal is to provide assurance of the absence of undeclared nuclear material and activities. The Model Protocol requires an expanded declaration that identifies a State's nuclear potential, empowers the IAEA to raise questions about the correctness and completeness of the State's declaration, and, if needed, allows IAEA access to locations. The information required and the locations available for access are much …
Date: May 25, 2010
Creator: Houck, F.; Rosenthal, M. & Wulf, N.
Object Type: Report
System: The UNT Digital Library
Accelerator Production Options for 99MO (open access)

Accelerator Production Options for 99MO

Shortages of {sup 99}Mo, the most commonly used diagnostic medical isotope, have caused great concern and have prompted numerous suggestions for alternate production methods. A wide variety of accelerator-based approaches have been suggested. In this paper we survey and compare the various accelerator-based approaches.
Date: August 25, 2010
Creator: Bertsche, Kirk
Object Type: Article
System: The UNT Digital Library
Forming Limits of Weld Metal in Aluminum Alloys and Advanced High-Strength Steels (open access)

Forming Limits of Weld Metal in Aluminum Alloys and Advanced High-Strength Steels

This work characterizes the mechanical properties of DP600 laser welded TWBs (1 mm-1.5 mm) near and in the weld, as well as their limits of formability. The approach uses simple uniaxial experiments to measure the variability in the forming limits of the weld region, and uses a theoretical forming limit diagram calculation to establish a probabilistic distribution of weld region imperfection using an M-K method approach
Date: October 25, 2010
Creator: Stephens, Elizabeth V.; Smith, Mark T.; Grant, Glenn J. & Davies, Richard W.
Object Type: Report
System: The UNT Digital Library
Overview of the 2009 Release of the Evaluated Nuclear Data Library (endl2009) (open access)

Overview of the 2009 Release of the Evaluated Nuclear Data Library (endl2009)

The Lawrence Livermore National Laboratory (LLNL) Physics Division has produced the next iteration of LLNL's evaluated nuclear database, ENDL2009. ENDL2009 is the second in a series of major ENDL library releases designed to support LLNL's current and future nuclear data needs. This library includes 585 distinct transport-ready evaluations in the neutron sub-library and many physics improvements for stockpile stewardship, attribution signatures, key radiochemical diagnostics and performance of conventional and hybrid fission/fusion reactors. In building this library, we adopted the best of the world's nuclear data efforts: 46% of the library is from the ENDF/B-VII.0 library, 10% is from the JENDL libraries and 8% from other libraries. The remaining 36% of the neutron sub-library and all of the charged-particle sub-libraries consist of new evaluations developed at LLNL for the ENDL2009 library. In addition, ENDL2009 supports new features such as energy-dependent Q values from fission, support for unresolved resonances and average momentum deposition. Finally, this release is our most highly tested release as we have strengthened our already rigorous testing regime by adding tests against LANL Activation Ratio Measurements and more than 1200 new critical assemblies. Our testing is now being incorporated into our development process and is serving to guide database …
Date: April 25, 2010
Creator: Brown, D. A.; Beck, B.; Descalle, M.; Hoffman, R.; Ormand, E.; Navratil, P. et al.
Object Type: Article
System: The UNT Digital Library
TRIMOLECULAR REACTIONS OF URANIUM HEXAFLUORIDE WITH WATER (open access)

TRIMOLECULAR REACTIONS OF URANIUM HEXAFLUORIDE WITH WATER

The hydrolysis reaction of uranium hexafluoride (UF{sub 6}) is a key step in the synthesis of uranium dioxide (UO{sub 2}) powder for nuclear fuels. Mechanisms for the hydrolysis reactions are studied here with density functional theory and the Stuttgart small-core scalar relativistic pseudopotential and associated basis set for uranium. The reaction of a single UF{sub 6} molecule with a water molecule in the gas phase has been previously predicted to proceed over a relatively sizeable barrier of 78.2 kJ {center_dot} mol{sup -1}, indicating this reaction is only feasible at elevated temperatures. Given the observed formation of a second morphology for the UO{sub 2} product coupled with the observations of rapid, spontaneous hydrolysis at ambient conditions, an alternate reaction pathway must exist. In the present work, two trimolecular hydrolysis mechanisms are studied with density functional theory: (1) the reaction between two UF{sub 6} molecules and one water molecule, and (2) the reaction of two water molecules with a single UF{sub 6} molecule. The predicted reaction of two UF{sub 6} molecules with one water molecule displays an interesting 'fluorine-shuttle' mechanism, a significant energy barrier of 69.0 kJ {center_dot} mol{sup -1} to the formation of UF{sub 5}OH, and an enthalpy of reaction ({Delta}H{sub …
Date: February 25, 2010
Creator: Westbrook, M.; Becnel, J. & Garrison, S.
Object Type: Article
System: The UNT Digital Library

Working With the Federal Fleets

Presentation about federal fleet data, working with the federal government, and results from a survey of Clean Cities coordinators about their experiences with regulated fleets.
Date: October 25, 2010
Creator: Daley, R.
Object Type: Presentation
System: The UNT Digital Library
Data Quality Objectives Supporting Radiological Air Emissions Monitoring for the PNNL Site (open access)

Data Quality Objectives Supporting Radiological Air Emissions Monitoring for the PNNL Site

This document of Data Quality Objectives (DQOs) was prepared based on the U.S. Environmental Protection Agency (EPA) Guidance on Systematic Planning Using the Data Quality Objectives Process, EPA, QA/G4, 2/2006 (EPA 2006) as well as several other published DQOs. Pacific Northwest National Laboratory (PNNL) is in the process of developing a radiological air monitoring program for the PNNL Site that is distinct from that of the nearby Hanford Site. Radiological emissions at the PNNL Site result from Physical Sciences Facility (PSF) major emissions units. A team was established to determine how the PNNL Site would meet federal regulations and address guidelines developed to monitor and estimate offsite air emissions of radioactive materials. The result is a program that monitors the impact to the public from the PNNL Site.
Date: May 25, 2010
Creator: Barnett, J. M.; Meier, Kirsten M.; Snyder, Sandra F.; Fritz, Brad G.; Poston, Ted M. & Rhoads, Kathleen
Object Type: Report
System: The UNT Digital Library
Development of a compact neutron source based on field ionization processes (open access)

Development of a compact neutron source based on field ionization processes

The authors report on the use of carbon nanofiber nanoemitters to ionize deuterium atoms for the generation of neutrons in a deuterium-deuterium reaction in a preloaded target. Acceleration voltages in the range of 50-80 kV are used. Field emission of electrons is investigated to characterize the emitters. The experimental setup and sample preparation are described and first data of neutron production are presented. Ongoing experiments to increase neutron production yields by optimizing the field emitter geometry and surface conditions are discussed.
Date: November 25, 2010
Creator: Persaud, Arun; Allen, Ian; Dickinson, Michael R.; Schenkel, Thomas; Kapadia, Rehan; Takei, Kuniharu et al.
Object Type: Article
System: The UNT Digital Library
340 Waste handling Facility Hazard Categorization and Safety Analysis (open access)

340 Waste handling Facility Hazard Categorization and Safety Analysis

The analysis presented in this document provides the basis for categorizing the facility as less than Hazard Category 3.
Date: October 25, 2010
Creator: Rodovsky, T. J.
Object Type: Report
System: The UNT Digital Library
Solenoid Compensation for the SuperB Interaction Region (open access)

Solenoid Compensation for the SuperB Interaction Region

We present an approach for compensating adverse effects of the detector solenoid in the SuperB Interaction Region (IR). We place compensating solenoids around the IR quadrupole magnets to reduce the magnetic fields nearly to zero. This allows more operational headroom for superconducting IR magnets and avoids saturation of ferric IR magnets. We place stronger compensating solenoids between IR magnets to reverse the magnetic field direction. This allows adjusting the total integrated solenoid field to zero, which eliminates coordinate plane rotation and reduces vertical beam displacements in the IR.
Date: August 25, 2010
Creator: Bertsche, Kirk & Sullivan, Michael K.
Object Type: Article
System: The UNT Digital Library
Activation Energy of Tantalum-Tungsten Oxide Thermite Reaction (open access)

Activation Energy of Tantalum-Tungsten Oxide Thermite Reaction

The activation energy of a high melting temperature sol-gel (SG) derived tantalum-tungsten oxide thermite composite was determined using the Kissinger isoconversion method. The SG derived powder was consolidated using the High Pressure Spark Plasma Sintering (HPSPS) technique to 300 and 400 C to produce pellets with dimensions of 5 mm diameter by 1.5 mm height. A custom built ignition setup was developed to measure ignition temperatures at high heating rates (500-2000 C {center_dot} min{sup -1}). Such heating rates were required in order to ignite the thermite composite. Unlike the 400 C samples, results show that the samples consolidated to 300 C undergo an abrupt change in temperature response prior to ignition. This change in temperature response has been attributed to the crystallization of the amorphous WO{sub 3} in the SG derived Ta-WO{sub 3} thermite composite and not to a pre-ignition reaction between the constituents. Ignition temperatures for the Ta-WO{sub 3} thermite ranged from approximately 465-670 C. The activation energy of the SG derived Ta-WO{sup 3} thermite composite consolidated to 300 and 400 C were determined to be 37.787 {+-} 1.58 kJ {center_dot} mol{sup -1} and 57.381 {+-} 2.26 kJ {center_dot} mol{sup -1}, respectively.
Date: February 25, 2010
Creator: Cervantes, O.; Kuntz, J.; Gash, A. & Munir, Z.
Object Type: Article
System: The UNT Digital Library
Pb Isotopes as an Indicator of the Asian Contribution to Particulate Air Pollution in Urban California (open access)

Pb Isotopes as an Indicator of the Asian Contribution to Particulate Air Pollution in Urban California

During the last two decades, expanding industrial activity in east Asia has led to increased production of airborne pollutants that can be transported to North America. Previous efforts to detect this trans-Pacific pollution have relied upon remote sensing and remote sample locations. We tested whether Pb isotope ratios in airborne particles can be used to directly evaluate the Asian contribution to airborne particles of anthropogenic origin in western North America, using a time series of samples from a pair of sites upwind and downwind of the San Francisco Bay Area. Our results for airborne Pb at these sites indicate a median value of 29 Asian origin, based on mixing relations between distinct regional sample groups. This trans-Pacific Pb is present in small quantities but serves as a tracer for airborne particles within the growing Asian industrial plume. We then applied this analysis to archived samples from urban sites in central California. Taken together, our results suggest that the analysis of Pb isotopes can reveal the distribution of airborne particles affected by Asian industrial pollution at urban sites in northern California. Under suitable circumstances, this analysis can improve understanding of the global transport of pollution, independent of transport models.
Date: October 25, 2010
Creator: Ewing, Stephanie A.; Christensen, John N.; Brown, Shaun T.; Vancuren, Richard A.; Cliff, Steven S. & DePaolo, Donald J.
Object Type: Article
System: The UNT Digital Library
Principal Component Analysis of Multi Spectral Data for Near Real Time Skin Chromophore Mapping (open access)

Principal Component Analysis of Multi Spectral Data for Near Real Time Skin Chromophore Mapping

None
Date: May 25, 2010
Creator: Kainerstorfer, J M; Ehler, M; Amyot, F; Hassan, M; Demos, S G; Chernomordik, V et al.
Object Type: Article
System: The UNT Digital Library
In Situ X-Ray Diffraction of the Delta to Alpha-Prime Transformation in Pu-Ga Alloys (open access)

In Situ X-Ray Diffraction of the Delta to Alpha-Prime Transformation in Pu-Ga Alloys

None
Date: May 25, 2010
Creator: Blobaum, K. J.; Jeffries, J. R.; Wall, M. A.; Cynn, H.; Evans, W. J. & Schwartz, A. J.
Object Type: Article
System: The UNT Digital Library
Gaussian Quadrature for Optical Design with Non-circular Pupils and Fields, and Broad Wavelength Ranges (open access)

Gaussian Quadrature for Optical Design with Non-circular Pupils and Fields, and Broad Wavelength Ranges

None
Date: June 25, 2010
Creator: Bauman, B J & Xiao, H
Object Type: Article
System: The UNT Digital Library
Billion-atom Synchronous Parallel Kinetic Monte Carlo Simulations of Critical 3D Ising Systems (open access)

Billion-atom Synchronous Parallel Kinetic Monte Carlo Simulations of Critical 3D Ising Systems

None
Date: May 25, 2010
Creator: Martinez, E.; Monasterio, P. R. & Marian, J.
Object Type: Article
System: The UNT Digital Library