Abstraction of Information From 2-  and 3-Dimensional Porflow Models Into a 1-D Goldsim Model - 11404 (open access)

Abstraction of Information From 2- and 3-Dimensional Porflow Models Into a 1-D Goldsim Model - 11404

The Savannah River National Laboratory has developed a 'hybrid' approach to Performance Assessment modeling which has been used for a number of Performance Assessments. This hybrid approach uses a multi-dimensional modeling platform (PorFlow) to develop deterministic flow fields and perform contaminant transport. The GoldSim modeling platform is used to develop the Sensitivity and Uncertainty analyses. Because these codes are performing complementary tasks, it is incumbent upon them that for the deterministic cases they produce very similar results. This paper discusses two very different waste forms, one with no engineered barriers and one with engineered barriers, each of which present different challenges to the abstraction of data. The hybrid approach to Performance Assessment modeling used at the SRNL uses a 2-D unsaturated zone (UZ) and a 3-D saturated zone (SZ) model in the PorFlow modeling platform. The UZ model consists of the waste zone and the unsaturated zoned between the waste zone and the water table. The SZ model consists of source cells beneath the waste form to the points of interest. Both models contain 'buffer' cells so that modeling domain boundaries do not adversely affect the calculation. The information pipeline between the two models is the contaminant flux. The domain …
Date: November 16, 2010
Creator: Taylor, G. & Hiergesell, R.
Object Type: Article
System: The UNT Digital Library
Activation Layer Stabilization of High Polarization Photocathodes in Sub-Optimal RF Gun Environments (open access)

Activation Layer Stabilization of High Polarization Photocathodes in Sub-Optimal RF Gun Environments

Specific activation recipes for bulk, 100 nm thick MBE grown and high polarization III-V photocathode material have been developed which mitigate the effects of exposure to background gasses. Lifetime data using four representative gasses were acquired for bulk GaAs, 100 nm unstrained GaAs and strained superlattice GaAs/GaAsP, all activated both with Cs and then Cs and Li (bi-alkali). Each photoemitter showed marked resilience improvement when activated using the bi-alkali recipe compared to the standard single alkali recipe. A dual alkali activation system at SLAC was constructed, baked and commissioned with the purpose of performing spin-polarization measurements on electrons emitted from the bi-alkali activated surfaces. An end station at SSRL was configured with the required sources for energy resolved photoemission measurements on the bi-alkali activated and CO2 dosed surfaces. The bi-alkali recipes were successfully implemented at SLAC/SSRL. Measurements at SLAC of the photoelectron spin-polarization from the modified activation surface showed no sign of a change in value compared to the standard activated material, i.e., no ill effects. Analysis of photoemission data indicates that the addition of Li to the activation layer results in a multi-layer structure. The presence of Li in the activation layer also acts as an inhibitor to CO2 …
Date: November 16, 2010
Creator: Mulhollan, Gregory A.
Object Type: Report
System: The UNT Digital Library
Adaptive and Efficient Computing for Subsurface Simulation within ParFlow (open access)

Adaptive and Efficient Computing for Subsurface Simulation within ParFlow

This project is concerned with the PF.WRF model as a means to enable more accurate predictions of wind fluctuations and subsurface storage. As developed at LLNL, PF.WRF couples a groundwater (subsurface) and surface water flow model (ParFlow) to a mesoscale atmospheric model (WRF, Weather Research and Forecasting Model). It was developed as a unique tool to address coupled water balance and wind energy questions that occur across traditionally separated research regimes of the atmosphere, land surface, and subsurface. PF.WRF is capable of simulating fluid, mass, and energy transport processes in groundwater, vadose zone, root zone, and land surface systems, including overland flow, and allows for the WRF model to both directly drive and respond to surface and subsurface hydrologic processes and conditions. The current PF.WRF model is constrained to have uniform spatial gridding below the land surface and matching areal grids with the WRF model at the land surface. There are often cases where it is advantageous for land surface, overland flow and subsurface models to have finer gridding than their atmospheric counterparts. Finer vertical discretization is also advantageous near the land surface (to properly capture feedbacks) yet many applications have a large vertical extent. However, the surface flow is …
Date: November 16, 2010
Creator: Tiedeman, H & Woodward, C S
Object Type: Report
System: The UNT Digital Library
Commercial Buildings Partnership Projects - Metered Data Format and Delivery (open access)

Commercial Buildings Partnership Projects - Metered Data Format and Delivery

A number of the Commercial Building Partnership Projects (CBPs) will require metering, monitoring, data analysis and verification of savings after the retrofits are complete. Although monitoring and verification (M&V) agents are free to use any metering and monitoring devices that they chose, the data they collect should be reported to Pacific Northwest National Laboratory (PNNL) in a standard format. PNNL will store the data collected in its CBP database for further use by PNNL and U.S. Department of Energy. This document describes the data storage process and the deliver format of the data from the M&V agents.
Date: November 16, 2010
Creator: Katipamula, Srinivas
Object Type: Report
System: The UNT Digital Library
Correlation Processing Of Local Seismic Data: Applications for Autonomous Sensor Deployments (open access)

Correlation Processing Of Local Seismic Data: Applications for Autonomous Sensor Deployments

Excavation and operation of an underground facility is likely to produce an extensive suite of seismic signals observable at the surface for perhaps several km. Probably a large fraction of such signals will be correlated, so the design of a monitoring framework should include consideration of a correlation processing capability. Correlation detectors have been shown to be significantly more sensitive than beam-forming power detectors. Although correlation detectors have a limited detection footprint, they can be generalized into multi-rank subspace detectors which are sensitive over a much larger range of source mechanisms and positions. Production of subspace detectors can be automated, so their use in an autonomous framework may be contemplated. Waveform correlation also can be used to produce very high precision phase picks which may be jointly inverted to simultaneously relocate groups of events. The relative precision of the resulting hypocenters is sufficient to visualize structural detail at a scale of less than a few tens of meters. Three possible correlation processor systems are presented. All use a subspace signal detection framework. The simplest system uses a single-component sensor and is capable of detection and classification of signals. The most complicated system uses many sensors deployed around the facility, and …
Date: November 16, 2010
Creator: Dodge, D A
Object Type: Report
System: The UNT Digital Library
Development of Compton Radiography Diagnostics for Inertial Confinement Fusion Implosions (open access)

Development of Compton Radiography Diagnostics for Inertial Confinement Fusion Implosions

An important diagnostic tool for inertial confinement fusion will be time-resolved radiographic imaging of the dense cold fuel surrounding the hot spot. The measurement technique is based on point-projection radiography at photon energies from 60-200 keV where the Compton effect is the dominant contributor to the opacity of the fuel or pusher. We have successfully applied this novel Compton Radiography technique to the study of the final compression of directly driven plastic capsules at the OMEGA facility. The radiographs have a spatial and temporal resolution of {approx}10 {micro}m and {approx}10ps, respectively. A statistical accuracy of {approx}0.5% in transmission per resolution element is achieved, allowing localized measurements of areal mass densities to 7% accuracy. The experimental results show 3D non-uniformities and lower than 1D expected areal densities attributed to drive asymmetries and hydroinstabilities.
Date: November 16, 2010
Creator: Tommasini, R.; Hatchett, S. P.; Hey, D. S.; Izumi, N.; Koch, J. A.; Landen, O. L. et al.
Object Type: Article
System: The UNT Digital Library
Empowering Minority Communities with Health Information - Howard (open access)

Empowering Minority Communities with Health Information - Howard

Training conducted as a part of the United Negro College Fund Special Programs/National Library of Medicine -HBCU ACCESS Project at Howard University, Washington, DC on November 20, 2010.
Date: November 16, 2010
Creator: McMurray, L. and R. Foster
Object Type: Book
System: The UNT Digital Library
Fabrication of a 238Pu target (open access)

Fabrication of a 238Pu target

Precision neutron-induced reaction data are important for modeling the network of isotope production and destruction within a given diagnostic chain. This network modeling has many applications such as the design of advanced fuel cycle for reactors and the interpretation of radiochemical data related to the stockpile stewardship and nuclear forensics projects. Our current funded effort is to improve the neutron-induced reaction data on the short-lived actinides and the specific goal is to improve the neutron capture data on {sup 238}Pu with a half-life of 87.7 years. In this report, the fabrication of a {sup 238}Pu target for the proposed measurement using the DANCE array at LANL is described. The {sup 238}Pu target was fabricated from a sample enriched to 99.35%, acquired from ORNL. A total of 395 {micro}g was electroplated onto both sides of a 3 {micro}m thick Ti foil using a custom-made plating cell, shown in Fig 1. The target-material loaded Ti foil is sandwiched between two double-side aluminized mylar foils with a thickness of 1.4 {micro}m. The mylar foil is glued to a polyimide ring. This arrangement is shown partially in Fig. 2. The assembled target is then inserted into an aluminum container with a wall thickness of …
Date: November 16, 2010
Creator: Wu, C Y; Chyzh, A; Kwan, E; Henderson, R; Gostic, J & Carter, D
Object Type: Report
System: The UNT Digital Library

In silico discovery of the dormancy regulons in a number of Actinobacteria genomes

Mycobacterium tuberculosis is a dangerous Actinobacteria infecting nearly one third of the human population. It becomes dormant and phenotypically drug resistant in response to stresses. An important feature of the M. tuberculosis pathogenesis is the prevalence of latent infection without disease, making understanding of the mechanisms used by the bacteria to exist in this state and to switch to metabolically active infectious form a vital problem to consider. M. tuberculosis dormancy is regulated by the three-component regulatory system of two kinases (DosT and DevS) and transcriprional regulator (DevR). DevR activates transcription of a set of genes, which allow the bacteria to survive long periods of anaerobiosis, and may be important for long-term survival within the host during latent infection. The DevR-regulon is studied experimentally in M. tuberculosis and few other phylogenetically close Mycobacteria spp. As many other two-component systems, the devRS operon is autoregulated. However, the mechanism of the dormancy is not completely clear even for these bacteria and there is no data describing the dormancy regulons in other species.
Date: November 16, 2010
Creator: Gerasimova, Anna; Dubchak, Inna; Arkin, Adam & Gelfand, Mikhail
Object Type: Poster
System: The UNT Digital Library
Modifications and Applications of the HERMES model: June - October 2010 (open access)

Modifications and Applications of the HERMES model: June - October 2010

The HERMES (High Explosive Response to MEchanical Stimulus) model has been developed to describe the response of energetic materials to low-velocity mechanical stimulus, referred to as HEVR (High Explosive Violent Response) or BVR (Burn to Violent Reaction). For tests performed with an HMX-based UK explosive, at sample sizes less than 200 g, the response was sometimes an explosion, but was not observed to be a detonation. The distinction between explosion and detonation can be important in assessing the effects of the HE response on nearby structures. A detonation proceeds as a supersonic shock wave supported by the release of energy that accompanies the transition from solid to high-pressure gas. For military high explosives, the shock wave velocity generally exceeds 7 km/s, and the pressure behind the shock wave generally exceeds 30 GPa. A kilogram of explosive would be converted to gas in 10 to 15 microseconds. An HEVR explosion proceeds much more slowly. Much of the explosive remains unreacted after the event. Peak pressures have been measured and calculated at less than 1 GPa, and the time for the portion of the solid that does react to form gas is about a millisecond. The explosion will, however, launch the confinement …
Date: November 16, 2010
Creator: Reaugh, J E
Object Type: Report
System: The UNT Digital Library
Production of high brightness H- beam by charge exchange of hydrogen atom beam in sodium jet (open access)

Production of high brightness H- beam by charge exchange of hydrogen atom beam in sodium jet

Production of H{sup -} beam for accelerators applications by charge exchange of high brightness hydrogen neutral beam in a sodium jet cell is experimentally studied in joint BNL-BINP experiment. In the experiment, a hydrogen-neutral beam with 3-6 keV energy, equivalent current up to 5 A and 200 microsecond pulse duration is used. The atomic beam is produced by charge exchange of a proton beam in a pulsed hydrogen target. Formation of the proton beam is performed in an ion source by four-electrode multiaperture ion-optical system. To achieve small beam emittance, the apertures in the ion-optical system have small enough size, and the extraction of ions is carried out from the surface of plasma emitter with a low transverse ion temperature of {approx}0.2 eV formed as a result of plasma jet expansion from the arc plasma generator. Developed for the BNL optically pumped polarized ion source, the sodium jet target with recirculation and aperture diameter of 2 cm is used in the experiment. At the first stage of the experiment H{sup -} beam with 36 mA current, 5 keV energy and {approx}0.15 cm {center_dot} mrad normalized emittance was obtained. To increase H{sup -} beam current ballistically focused hydrogen neutral beam will …
Date: November 16, 2010
Creator: Davydenko, V.; Zelenski, A.; Ivanov, A. & Kolmogorov, A.
Object Type: Article
System: The UNT Digital Library
Spectroscopic Evidence for Exceptional Thermal Contribution to Electron-Beam Induced Fragmentation (open access)

Spectroscopic Evidence for Exceptional Thermal Contribution to Electron-Beam Induced Fragmentation

While electron beam induced fragmentation (EBIF) has been reported to result in the formation of nanocrystals of various compositions, the physical forces driving this phenomenon are still poorly understood. We report EBIF to be a much more general phenomenon than previously appreciated, operative across a wide variety of metals, semiconductors and insulators. In addition, we leverage the temperature dependent bandgap of several semiconductors to quantify -- using in situ cathodoluminescence spectroscopy -- the thermal contribution to EBIF, and find extreme temperature rises upwards of 1000K.
Date: November 16, 2010
Creator: Caldwell, Marissa A.; Haynor, Ben; Aloni, Shaul; Ogletree, D. Frank; Wong, H.-S. Philip; Urban, Jeffrey J. et al.
Object Type: Article
System: The UNT Digital Library