Unstructured Mesh Connectivity in Unstructured Mapping (open access)

Unstructured Mesh Connectivity in Unstructured Mapping

The connectivity interface for UnstructuredMapping has been rewritten to provide a more thorough interface to the mesh. This new design also resembles the TSTT mesh query interface. While data is still stored in array form, indexed by integers, the interface provides iterators through the mesh entities and adjacencies. This document describes the additions to the UnstructuredMapping class as well as the definition and use of the UnstructuredMappingIterator and UnstructuredMappingAdjacencyIterator classes.
Date: October 22, 2002
Creator: Chand, K
Object Type: Text
System: The UNT Digital Library
Facilities for Development of Modified Nitride-Based Fuel Pellets (open access)

Facilities for Development of Modified Nitride-Based Fuel Pellets

Facilities to support development of modified nitride-based reactor fuel pellets have been activated and are now in operation at Lawrence Livermore National Laboratory. These facilities provide the controls and monitored laboratory conditions required to produce, evaluate, and verify quality of the nitride-based product required for this fuel application. By preserving the high melting point, high thermal conductivity, and high actinide density properties of nitride fuel while enhancing stoichiometry, density, and grain structure, and by applying inert matrix (ZrN) and neutron absorbing (HfN) additives for improved stability and burn-up characteristics, the requirements for a long-life fuel to support sealed core reactor applications may be met. This paper discusses requirements for producing the modified nitride powders for sintering of fuel pellets, translation of these requirements into facility specifications, and implementation of these specifications as facility capabilities.
Date: October 22, 2003
Creator: Meier, T.; Ebbinghaus, B. & Choi, J.
Object Type: Article
System: The UNT Digital Library
Evaluation of the Relative Importance of Parameters Influencing Perforation Cleanup (open access)

Evaluation of the Relative Importance of Parameters Influencing Perforation Cleanup

Completion of cased and cemented wells by shaped-charge perforation results in damage to the formation, which can significantly reduce well productivity. Typically, underbalanced conditions are imposed during perforation in an effort to remove damaged rock and shaped-charge debris from the perforation tunnel. Immediately after the shaped-charge jet penetrates the formation, there is a transient surge of fluid from the formation through the perforation and into the well bore. Experimental evidence suggests that it is this transient pressure surge that leads to the removal of damaged rock and charge debris leaving an open perforation tunnel. We have developed a two-stage computational model to simulate the perforation process and subsequent pressure surge and debris removal. The first stage of the model couples a hydrocode with a model of stress-induced permeability evolution to calculate damage to the formation and the resulting permeability field. The second stage simulates the non-Darcy, transient fluid flow from the formation and removes damaged rock and charge debris from the perforation tunnel. We compare the model to a series of API RP43 section 4 flow tests and explore the influence of fluid viscosity and rock strength on the final perforation geometry and permeability.
Date: October 22, 2003
Creator: Detwiler, R L; Morris, J P; Karacan, C O; Halleck, P M & Hardesty, J
Object Type: Article
System: The UNT Digital Library
Density-functional calculations of a, b, g, d, dp, and e plutonium (open access)

Density-functional calculations of a, b, g, d, dp, and e plutonium

Total energies for the six known polymorphs of plutonium metal have been calculated within spin and orbital polarized density-functional theory as a function of lattice constant. Theoretical equilibrium volumes and bulk moduli correspond well with experimental data and the calculated total energies are consistent with the known phase diagram of Pu. It is shown that a preference for formation of magnetic moments, increasing through the {alpha} {yields} {beta} {yields} {gamma} phases, explain their position in the ambient pressure phase diagram and their anomalous variation of atomic density. A simple model is presented that establishes a relationship between atomic density, crystal symmetry, and magnetic moments which is universally valid for all Pu phases.
Date: October 22, 2003
Creator: Soderlind, P & Sadigh, B
Object Type: Article
System: The UNT Digital Library
Comprehensive Assignment of Mass Spectral Signatures from Individual Bacillus atrophaeus Spores in Matrix-Free Bioaerosol Mass Spectrometry (open access)

Comprehensive Assignment of Mass Spectral Signatures from Individual Bacillus atrophaeus Spores in Matrix-Free Bioaerosol Mass Spectrometry

We have conducted studies to fully characterize the mass spectral signature of individual Bacillus atrophaeus, previously known as Bacillus subtilis var niger or Bacillus globigii, spores obtained in matrix-free bioaerosol mass spectrometry (BAMS). Mass spectra of spores grown in unlabeled, {sup 13}C-labeled and {sup 15}N-labeled growth media are used to determine the number of carbon and nitrogen atoms associated with each mass peak. To determine the parent ion structure associated with fragment ions present in the spore spectra, the mass-to-charge (m/z) fragmentation pattern of several chemical standards was obtained. Our results agree with prior assignments of dipicolinic acid, amino acids and calcium complex ions made in the spore mass spectra. Identity of several previously unidentified mass peaks, key to recognition of Bacillus spore by matrix-free BAMS, is revealed. Specifically, a set of fragment peaks in the negative polarity is shown to be consistent with the fragmentation pattern of purine nucleobase containing compounds. The identity of m/z=+74, a marker peak that helps discriminate Bacillus atrophaeus from Bacillus thuringiensis spores grown in rich medium, is surprisingly a non-description, viz. [N{sub 1}C{sub 4}H{sub 12}]{sup +}. A probable precursor molecule for the [N{sub 1}C{sub 4}H{sub 12}]{sup +} ion observed in spore spectra is trimethyl …
Date: October 22, 2004
Creator: Srivastava, A; Pitesky, M; Steele, P; Tobias, H; Fergenson, D P; Horn, J et al.
Object Type: Article
System: The UNT Digital Library
A "numerical microscope" for plasma physics (open access)

A "numerical microscope" for plasma physics

Computer simulation of plasmas is important to a number of fields in both science and industry, including particle accelerators (because beams of charged particles are non-neutral plasmas), high-power vacuum tubes, and advanced microcircuit fabrication and plasma processing of materials. Researchers at the Heavy Ion Fusion Virtual National Laboratory (HIF-VNL) and LBNL's Computational Research Division have prototyped key elements of a new approach that uses adaptive-mesh refinement to increase both the speed and the accuracy of these simulations.
Date: October 22, 2003
Creator: Friedman, A; Vay, J & Colella, P
Object Type: Article
System: The UNT Digital Library
IEEE 802.11 Wireless LAN Security White Paper (open access)

IEEE 802.11 Wireless LAN Security White Paper

Given the increased productivity and growing popularity of wireless communications in general, and wireless data communications in particular, this paper outlines the protocols, security implications, and architectures of IEEE Std. 802.11-1999 wireless LANs (WLANs) and makes recommendations regarding a phased implementation of WLANs at LLNL. This project is driven by the need for convenient and secure access to the Internet for Laboratory visitors and to the internal network for Laboratory employees. A solid architecture designed with a priority on security will allow LLNL to offer network access in areas where it is traditionally hard to deploy wired networks. It will also enable such services as wireless access for inventory control and convenient network access for conference rooms around LLNL. Wireless network access has the potential to increase productivity by enabling instant access to information.
Date: October 22, 2001
Creator: King, Jason S.
Object Type: Report
System: The UNT Digital Library
Arbitrary Lagrangian-Eulerian Method with Local Structured Adaptive Mesh Refinement for Modeling Shock Hydrodynamics (open access)

Arbitrary Lagrangian-Eulerian Method with Local Structured Adaptive Mesh Refinement for Modeling Shock Hydrodynamics

A new method that combines staggered grid Arbitrary Lagrangian-Eulerian (ALE) techniques with structured local adaptive mesh refinement (AMR) has been developed for solution of the Euler equations. This method facilitates the solution of problems currently at and beyond the boundary of soluble problems by traditional ALE methods by focusing computational resources where they are required through dynamic adaption. Many of the core issues involved in the development of the combined ALEAMR method hinge upon the integration of AMR with a staggered grid Lagrangian integration method. The novel components of the method are mainly driven by the need to reconcile traditional AMR techniques, which are typically employed on stationary meshes with cell-centered quantities, with the staggered grids and grid motion employed by Lagrangian methods. Numerical examples are presented which demonstrate the accuracy and efficiency of the method.
Date: October 22, 2001
Creator: Anderson, R W; Pember, R B & Elliott, N S
Object Type: Article
System: The UNT Digital Library
A Modified Nitride-Based Fuel for Long Core Life and Proliferation Resistance (open access)

A Modified Nitride-Based Fuel for Long Core Life and Proliferation Resistance

A modified nitride-based uranium fuel to support the small, secured, transportable, and autonomous reactor (SSTAR) concept is initiated at Lawrence Livermore National laboratory (LLNL). This project centers on the evaluation of modified uranium nitride fuels imbedded with other inert (e.g. ZrN), neutron-absorbing (e.g. HfN) , or breeding (e.g. ThN) nitrides to enhance the fuel properties to achieve long core life with a compact reactor design. A long-life fuel could minimize the need for on-site refueling and spent-fuel storage. As a result, it could significantly improve the proliferation resistance of the reactor/fuel systems. This paper discusses the potential benefits and detriments of modified nitride-based fuels using the criteria of compactness, long-life, proliferation resistance, fuel safety, and waste management. Benefits and detriments are then considered in recommending a select set of compositions for further study.
Date: October 22, 2003
Creator: Ebbinghaus, B.; Choi, J. & Meier, T.
Object Type: Article
System: The UNT Digital Library
Changes in Perforation-Induced Formation Damage With Degree of Underbalance: Comparison of Sandstone and Limestone Formations (open access)

Changes in Perforation-Induced Formation Damage With Degree of Underbalance: Comparison of Sandstone and Limestone Formations

Field data and recently developed models provide some guidance for estimating the underbalance needed to obtain fully functional perforations, but there are little data available that relate flow efficiency to lower underbalances in different rock types. To improve understanding of the surge cleanup process, we have performed two series of perforation flow tests in Berea Sandstone and in Bedford Limestone cores at increasing levels of underbalance. Flow tests were performed according to modified API RP43, section 4 test procedures. At the conclusion of the tests, the cores were analyzed using high-resolution X-ray CT techniques. The shape, dimensions and total volumes of both the open tunnel and the remaining embedded liner metal were extracted from the CT data and correlated with the underbalance and with the flow test results. Open tunnel diameters and volumes are much lower in the limestone samples. While the amount of metal remaining in the tunnel and at the perforation tip decreases dramatically with underbalance in Berea Sandstone cores, the amount of metal is nearly constant in the limestone cores. Conversely, the tunnel volume increases with underbalance in the Sandstone cores but stays constant in the limestone. Core flow efficiency results correlate with these observations. There is …
Date: October 22, 2003
Creator: Detwiler, R; Halleck, P M; Karacan, C O & Hardesty, J
Object Type: Article
System: The UNT Digital Library
Connectivity in Random Grain Boundary Networks (open access)

Connectivity in Random Grain Boundary Networks

Mechanical properties of FCC metals and alloys can be improved by exercising control over the population of grain boundary types in the microstructure. The existing studies also suggest that such properties tend to have percolative mechanisms that depend on the topology of the grain boundary network. With the emergence of SEM-based automated electron backscatter diffraction (EBSD), statistically significant datasets of interface crystallography can be analyzed in a routine manner, giving new insight into the topology and percolative properties of grain boundary networks. In this work, we review advanced analysis techniques for EBSD datasets to quantify microstructures in terms of grain boundary character and triple junction distributions, as well as detailed percolation-theory based cluster analysis.
Date: October 22, 2002
Creator: Kumar, M; Schuh, C A & King, W E
Object Type: Article
System: The UNT Digital Library
Electron Radiation Effects in Low-K Dielectric Materials (open access)

Electron Radiation Effects in Low-K Dielectric Materials

Positron annihilation spectroscopy was used to study microstructural changes in low-k interlevel dielectrics under emulated electron irradiation of up to 1 Mrad(Si) dose, and the impact of the degradation of materials properties on device performance.
Date: October 22, 2003
Creator: Jenei, Zs.; Petkov, M. P.; Asoka-Kumar, P.; Miller, R. D. & Volksen, W.
Object Type: Article
System: The UNT Digital Library
Modeling of Capillary Discharge Plasma for X-Ray Lasers, XUV Lithography and Other Applications (open access)

Modeling of Capillary Discharge Plasma for X-Ray Lasers, XUV Lithography and Other Applications

It is long ago recognized that Z-pinches represent very natural medium for x-ray lasers (XRL) due to its favorable geometry and achievable high densities and temperatures. They also are very efficient x-ray sources. One of their variants, the capillary discharges, attracted attention of plasma physics researchers for almost two decades. It has been used for hot dense plasma formation and x-ray lasers[1,2], for transportation of laser beams and XUV radiation generation in x-ray lithography[3,4], for basic Z-pinch research and some others. The combination of efficiency, simplicity and low cost of capillary electrical discharges allowed to scale capillary x-ray lasers to table-top dimensions. In this paper we show the modeling results for next, 3-4 times shorter wavelength x-ray lasers. As an efficient x-ray source of line and continuum radiation it can be used for many practically important application in science and technology. In particular, the capillary discharge can appear as powerful potential candidate for emerging XUV microlithography. We present here the results of numerical modeling of spectra and density of Xe EUV source which involved plasma heating and dynamics, detailed atomic kinetics and radiation transport and material ablation physics.
Date: October 22, 2002
Creator: Shlyaptsev, V. N.; Dunn, J.; Moon, S. J.; Fournier, K. B.; Osterheld, A. L.; Rocca, J. J. et al.
Object Type: Article
System: The UNT Digital Library
Aerial Image Microscopes for the Inspection of Defects in EUV Masks (open access)

Aerial Image Microscopes for the Inspection of Defects in EUV Masks

The high volume inspection equipment currently available to support development of EUV blanks is non-actinic. The same is anticipated for patterned EUV mask inspection. Once potential defects are identified and located by such non-actinic inspection techniques, it is essential to have instrumentation to perform detailed characterization, and if repairs are performed, re-evaluation. The ultimate metric for the acceptance or rejection of a mask due to a defect, is the wafer level impact. Thus measuring the aerial image for the site under question is required. An EUV Aerial Image Microscope (''AIM'') similar to the current AIM tools for 248nm and 193nm exposure wavelength is the natural solution for this task. Due to the complicated manufacturing process of EUV blanks, AIM measurements might also be beneficial to accurately assessing the severity of a blank defect. This is an additional application for an EUV AIM as compared to today's use In recognition of the critical role of an EUV AIM for the successful implementation of EUV blank and mask supply, International SEMATECH initiated this design study with the purpose to define the technical requirements for accurately simulating EUV scanner performance, demonstrating the feasibility to meet these requirements and to explore various technical approaches …
Date: October 22, 2002
Creator: Barty, A.; Taylor, J. S.; Hudyma, R.; Spiller, E.; Sweeney, D. W.; Shelden, G. et al.
Object Type: Article
System: The UNT Digital Library
A Markov Chain Monte Carlo Based Method for System Identification (open access)

A Markov Chain Monte Carlo Based Method for System Identification

This paper describes a novel methodology for the identification of mechanical systems and structures from vibration response measurements. It combines prior information, observational data and predictive finite element models to produce configurations and system parameter values that are most consistent with the available data and model. Bayesian inference and a Metropolis simulation algorithm form the basis for this approach. The resulting process enables the estimation of distributions of both individual parameters and system-wide states. Attractive features of this approach include its ability to: (1) provide quantitative measures of the uncertainty of a generated estimate; (2) function effectively when exposed to degraded conditions including: noisy data, incomplete data sets and model misspecification; (3) allow alternative estimates to be produced and compared, and (4) incrementally update initial estimates and analysis as more data becomes available. A series of test cases based on a simple fixed-free cantilever beam is presented. These results demonstrate that the algorithm is able to identify the system, based on the stiffness matrix, given applied force and resultant nodal displacements. Moreover, it effectively identifies locations on the beam where damage (represented by a change in elastic modulus) was specified.
Date: October 22, 2002
Creator: Glaser, R. E.; Lee, C. L.; Nitao, J. J. & Hanley, W. G.
Object Type: Article
System: The UNT Digital Library
Texas Disease Prevention News, Volume 61, Number 22, October 2001 (open access)

Texas Disease Prevention News, Volume 61, Number 22, October 2001

Newsletter of the Texas Department of Health discussing the news, activities, and events of the organization and other information related to health in Texas.
Date: October 22, 2001
Creator: Texas. Department of Health.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Comments on Economides and Ehlig-Economides,"Sequestering carbon dioxide in a closed underground volume," SPE 124430, October 2009 (open access)

Comments on Economides and Ehlig-Economides,"Sequestering carbon dioxide in a closed underground volume," SPE 124430, October 2009

The paper examines the pressure increase resulting from injection of CO2 into a 1D radial system with closed boundaries. The finding is that unacceptably high pressures are obtained when only 1% or less of the pore volume is occupied by injected CO2. These results are used to make the general conclusion that large-scale CCS is not feasible.
Date: October 22, 2009
Creator: Oldenburg, Curt; Pruess, Karsten; Birkholzer, Jens & Doughty, Christine
Object Type: Report
System: The UNT Digital Library
EVALUATION OF FLOWSHEET CHANGES FOR THE HIGHLY ENRICHED URANIUM BLENDDOWN PROGRAM (open access)

EVALUATION OF FLOWSHEET CHANGES FOR THE HIGHLY ENRICHED URANIUM BLENDDOWN PROGRAM

H Canyon is considering a flowsheet change for Plutonium (Pu) Contaminated Scrap (PuCS) material. The proposed change is to route dissolved PuCS material directly to a uranium (U) storage tank. As a result, the PuCS solution will bypass Head End and First U Cycle, and will be purified by solvent extraction in Second U Cycle. The PuCS solution contains appreciable amounts of boron (B) and fluoride (F{sup -}), which are currently at trace levels in the U storage tank. Though unlikely, if the B concentration in the U storage tank were to reach 1.8 g B/g U, the entire contents of the U storage tank would likely require a second pass through Second U Cycle to provide sufficient decontamination to meet the Tennessee Valley Authority (TVA) Blend Grade Highly Enriched Uranium (HEU) specification for B, which is 30 {micro}g/g U. In addition, Second U Cycle is expected to provide sufficient decontamination of F{sup -} and Pu regardless of the amount of PuCS solution sent to the storage tank. Though aluminum (Al) is not present in the PuCS solution, B can be credited as a complexant of F{sup -}. Both stability constants from the literature and Savannah River National Laboratory (SRNL) …
Date: October 22, 2007
Creator: Crowder, M.; Rudisill, T.; Laurinat, J. & Mickalonis, J.
Object Type: Article
System: The UNT Digital Library
RE-EVALUATION OF THE PERMEABLE MATERIAL AT THE BASE OF THE UNCONFINED AQUIFER NEAR LERF HANFORD SITE WASHINGTON (open access)

RE-EVALUATION OF THE PERMEABLE MATERIAL AT THE BASE OF THE UNCONFINED AQUIFER NEAR LERF HANFORD SITE WASHINGTON

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Date: October 22, 2009
Creator: Smoot, J. L.
Object Type: Article
System: The UNT Digital Library
Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring, and Evaluation, FY09 Annual Report (open access)

Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring, and Evaluation, FY09 Annual Report

This document is the annual report for fiscal year 2009 (FY09) for the project called Facilitation of the Estuary/Ocean Subgroup (EOS). The EOS is part of the research, monitoring, and evaluation (RME) effort developed by the Action Agencies (Bonneville Power Administration [BPA], U.S. Army Corps of Engineers [Corps or USACE], U.S. Bureau of Reclamation) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS).
Date: October 22, 2009
Creator: Johnson, Gary E.
Object Type: Report
System: The UNT Digital Library
Next Generation Safeguards Initiative Workshop on Enhanced Recruiting for International Safeguards (open access)

Next Generation Safeguards Initiative Workshop on Enhanced Recruiting for International Safeguards

In 2007, the National Nuclear Security Administration's Office of Nonproliferation and International Security (NA-24) completed a yearlong review of the challenges facing the international safeguards system today and over the next 25 years. The study found that without new investment in international safeguards, the U.S. safeguards technology base, and our ability to support International Atomic Energy Agency (IAEA) safeguards, will continue to erode and soon may be at risk. To reverse this trend, the then U.S. Secretary of Energy, Samuel Bodman, announced at the 2007 IAEA General Conference that the Department of Energy (DOE) would launch the Next Generation Safeguards Initiative (NGSI). He stated 'IAEA safeguards must be robust and capable of addressing proliferation threats. Full confidence in IAEA safeguards is essential for nuclear power to grow safely and securely. To this end, the U.S. Department of Energy will seek to ensure that modern technology, the best scientific expertise, and adequate resources are available to keep pace with expanding IAEA responsibilities.' To meet this goal, the NGSI objectives include the recruitment of international safeguards experts to work at the U.S. national laboratories and to serve at the IAEA's headquarters. Part of the latter effort will involve enhancing our existing efforts …
Date: October 22, 2008
Creator: Pepper, S.; Rosenthal, M.; Fishbone, L.; Occhiogrosso, D.; Carroll, C.; Dreicer, M. et al.
Object Type: Article
System: The UNT Digital Library
Economic Globalization and a Nuclear Renaissance (open access)

Economic Globalization and a Nuclear Renaissance

The phenomenon of globalization has become increasingly well recognized, documented, and analyzed in the last several years. Globalization, the integration of markets and intra-firm competition on a worldwide basis, involves complex behavioral and mindset changes within a firm that facilitate global competition. The changes revolve around efficient information flow and rapid deployment of technology. The objective of this report is to examine the probable characteristics of a global nuclear renaissance and its broad implications for industry structure and export control relative to nuclear technology. The question of how a modern renaissance would affect the trend toward globalization of the nuclear industry is addressed.
Date: October 22, 2001
Creator: Wood, Thomas W.; Johnson, Wayne L. & Parker, Brian M.
Object Type: Report
System: The UNT Digital Library
Renewable Energy Opportunities Saginaw Chippewa Indian Tribe (open access)

Renewable Energy Opportunities Saginaw Chippewa Indian Tribe

The Saginaw Chippewa Indian Tribe has a vision to become self-sufficient in its energy needs and to maintain its culture and protect Mother Earth with respect and honor for the next seven generations. To achieve this vision, green energy sources such as solar, wind and biomass energy are the best energy paths to travel. In this feasibility study the Tribe has analyzed and provided data on the nature of the renewable resources available to the Tribe and the costs of implementing these technologies.
Date: October 22, 2008
Creator: Saginaw Chippewa Indian Tribe Planning Department
Object Type: Report
System: The UNT Digital Library
Angular Dependence of Jet Quenching Indicates Its Strong Enhancement Near the QCD Phase Transition (open access)

Angular Dependence of Jet Quenching Indicates Its Strong Enhancement Near the QCD Phase Transition

We study dependence of jet quenching on matter density, using 'tomography' of the fireball provided by RHIC data on azimuthal anisotropy v{sub 2} of high p{sub t} hadron yield at different centralities. Slicing the fireball into shells with constant (entropy) density, we derive a 'layer-wise geometrical limit' v{sub 2}{sup max} which is indeed above the data v{sub 2} < v{sub x}{sup max}. Interestingly, the limit is reached only if quenching is dominated by shells with the entropy density exactly in the near-T{sub c} region. We show two models that simultaneously describe the high p{sub t} v{sub 2} and R{sub AA} data and conclude that such a description can be achieved only if the jet quenching is few times stronger in the near-T{sub c} region relative to QGP at T > T{sub c}. One possible reason for that may be recent indications that the near-T{sub c} region is a magnetic plasma of relatively light color-magnetic monopoles.
Date: October 22, 2008
Creator: Liao, Jinfeng & Shuryak, Edward
Object Type: Article
System: The UNT Digital Library