Chemistry Resolved Kinetic Flow Modeling of TATB Based Explosives (open access)

Chemistry Resolved Kinetic Flow Modeling of TATB Based Explosives

Detonation waves in insensitive, TATB based explosives are believed to have multi-time scale regimes. The initial burn rate of such explosives has a sub-microsecond time scale. However, significant late-time slow release in energy is believed to occur due to diffusion limited growth of carbon. In the intermediate time scale concentrations of product species likely change from being in equilibrium to being kinetic rate controlled. They use the thermo-chemical code CHEETAH linked to an ALE hydrodynamics code to model detonations. They term their model chemistry resolved kinetic flow as CHEETAH tracks the time dependent concentrations of individual species in the detonation wave and calculates EOS values based on the concentrations. A HE-validation suite of model simulations compared to experiments at ambient, hot, and cold temperatures has been developed. They present here a new rate model and comparison with experimental data.
Date: July 21, 2011
Creator: Vitello, P A; Fried, L E; Howard, W M; Levesque, G & Souers, P C
Object Type: Article
System: The UNT Digital Library
Comparison of Sequential Designs of Computer Experiments in High Dimensions (open access)

Comparison of Sequential Designs of Computer Experiments in High Dimensions

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Date: July 21, 2011
Creator: Kupresanin, A M & Johannesson, G
Object Type: Report
System: The UNT Digital Library
DuraLith Alkali-Aluminosilicate Geopolymer Waste Form Testing for Hanford Secondary Waste (open access)

DuraLith Alkali-Aluminosilicate Geopolymer Waste Form Testing for Hanford Secondary Waste

The primary objective of the work reported here was to develop additional information regarding the DuraLith alkali aluminosilicate geopolymer as a waste form for liquid secondary waste to support selection of a final waste form for the Hanford Tank Waste Treatment and Immobilization Plant secondary liquid wastes to be disposed in the Integrated Disposal Facility on the Hanford Site. Testing focused on optimizing waste loading, improving waste form performance, and evaluating the robustness of the waste form with respect to waste variability.
Date: July 21, 2011
Creator: Gong, W. L.; Lutz, Werner & Pegg, Ian L.
Object Type: Report
System: The UNT Digital Library
Epitaxial Fe{sub 3-x}Ti{sub x}O{sub 4} films from magnetite to ulvöspinel by pulsed laser deposition (open access)

Epitaxial Fe{sub 3-x}Ti{sub x}O{sub 4} films from magnetite to ulvöspinel by pulsed laser deposition

Epitaxial films along the Fe{sub 3-x}Ti{sub x}O{sub 4} (titanomagnetite) compositional series from pure end-members magnetite (Fe{sub 3}O{sub 4}) to ulvöspinel (Fe{sub 2}TiO{sub 4}) were successfully grown by pulsed laser deposition on MgO(100) substrates. Spectroscopic characterization including high resolution x-ray diffraction, x-ray photoelectron spectroscopy, and synchrotron-based x-ray absorption and magnetic circular dichroism consistently shows that Ti(IV) substitutes for Fe(III) in the inverse spinel lattice with a proportional increase in lattice Fe(II) concentration. No evidence of Ti interstitials, spinodal decomposition, or secondary phases was found in the bulk of the grown films. At the uppermost few nanometers of the Ti-bearing film surfaces, evidence suggests that Fe(II) is susceptible to facile oxidation, and that an associated lower Fe/Ti ratio in this region is consistent with surface compositional incompleteness or alteration to a titanomaghemite-like composition and structure. The surface of these films nonetheless appear to remain highly ordered and commensurate with the underlying structure despite facile oxidation, a surface condition that is found to be reversible to some extent by heating in low oxygen environments.
Date: July 21, 2011
Creator: Droubay, T. C.; Pearce, C. I.; Ilton, E. S.; Engelhard, M. H.; Jiang, W.; Heald, S. M. et al.
Object Type: Article
System: The UNT Digital Library
NA-42 TI Shared Software Component Library FY2011 Final Report (open access)

NA-42 TI Shared Software Component Library FY2011 Final Report

The NA-42 TI program initiated an effort in FY2010 to standardize its software development efforts with the long term goal of migrating toward a software management approach that will allow for the sharing and reuse of code developed within the TI program, improve integration, ensure a level of software documentation, and reduce development costs. The Pacific Northwest National Laboratory (PNNL) has been tasked with two activities that support this mission. PNNL has been tasked with the identification, selection, and implementation of a Shared Software Component Library. The intent of the library is to provide a common repository that is accessible by all authorized NA-42 software development teams. The repository facilitates software reuse through a searchable and easy to use web based interface. As software is submitted to the repository, the component registration process captures meta-data and provides version control for compiled libraries, documentation, and source code. This meta-data is then available for retrieval and review as part of library search results. In FY2010, PNNL and staff from the Remote Sensing Laboratory (RSL) teamed up to develop a software application with the goal of replacing the aging Aerial Measuring System (AMS). The application under development includes an Advanced Visualization and Integration …
Date: July 21, 2011
Creator: Knudson, Christa K.; Rutz, Frederick C. & Dorow, Kevin E.
Object Type: Report
System: The UNT Digital Library
The r-process in Metal Poor Stars, and Black Hole Formation (open access)

The r-process in Metal Poor Stars, and Black Hole Formation

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Date: July 21, 2011
Creator: Boyd, R. N.; Famiano, M. A.; Meyer, B. S.; Motizuki, Y.; Kajino, T. & Roederer, I. U.
Object Type: Article
System: The UNT Digital Library
Techniques For Injection Of Pre-Charaterized Dust Into The Scrape Off Layer Of Fusion Plasma (open access)

Techniques For Injection Of Pre-Charaterized Dust Into The Scrape Off Layer Of Fusion Plasma

Introduction of micron-sized dust into the scrape-off layer (SOL) of a plasma has recently found many applications aimed primarily at determining dust behavior in future fusion reactors. The dust particles are typically composed of materials intrinsic to a fusion reactor. On DIII-D and TEXTOR carbon dust has been introduced into the SOL using a probe inserted from below into the divertor region. On NSTX, both Li and tungsten dust have been dropped from the top of the machine into the SOL throughout the duration of a discharge, by utilizing a vibrating piezoelectric based particle dropper. The original particle dropper was developed to inject passivated Li powder {approx} 40 {mu}m in diameter into the SOL to enhance plasma performance. A simplified version of the dropper was developed to introduce trace amounts of tungsten powder for only a few discharges, thus not requiring a large powder reservoir. The particles emit visible light from plasma interactions and can be tracked by either spectroscopic means or by fast frame rate visible cameras. This data can then be compared with dust transport codes such as DUSTT to make predictions of dust behavior in next-step devices such as ITER. For complete modeling results, it is desired …
Date: July 21, 2011
Creator: Roquemore, A. L.; John, B.; Friesen, F.; Hartzfeld, K. & Mansfield, D. K.
Object Type: Report
System: The UNT Digital Library