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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
Analyses in Support of Z-IFE: LLNL Progress Report for FY-04
During the last quarter of FY2004, Lawrence Livermore National Laboratory (LLNL) conducted a brief study of power plant options for a z-pinch-based inertial fusion energy (Z-IFE) power plant. Areas that were covered include chamber design, thick-liquid response, neutronics and activation, and systems studies. This report summarizes the progress made in each of these areas, provides recommendations for improvements to the basic design concept, and identifies future work that is needed. As a starting point to the LLNL studies, we have taken information provided in several publications and presentations. In particular, many of the basic parameters were taken from the ZP-3 study, which is described in reference 4. The ZP-3 design called for 12 separate target chambers, with any 10 of them operating at a given time. Each chamber would be pulsed at a repetition rate of 0.1 Hz with a target yield of 3 GJ. Thus, each chamber would have a fusion power of 300 MW for a power plant total of 3000 MW. The ZP-3 study considered several options for the recyclable transmission lines (RTL). Early in the study, the LLNL group questioned the use of many chambers as well as the yield limitation of 3 GJ. The feeling …
Date:
October 6, 2004
Creator:
Meier, W; Abbott, R; Latkowski, J; Moir, R; Reyes, S & Schmitt, R
Object Type:
Report
System:
The UNT Digital Library
Investigating Sources of Toxicity in Stormwater: Algae Mortality in Runoff Upstream of the Lawrence Livermore National Laboratory
A source evaluation case study is presented for observations of algae toxicity in an intermittent stream passing through the Lawrence Livermore National Laboratory near Livermore, California. A five-step procedure is discussed to determine the cause of water toxicity problems and to determine appropriate environmental management practices. Using this approach, an upstream electrical transfer station was identified as the probable source of herbicides causing the toxicity. In addition, an analytical solution for solute transport in overland flow was used to estimate the application level of 40 Kg/ha. Finally, this source investigation demonstrates that pesticides can impact stream water quality regardless of application within levels suggested on manufacturer labels. Environmental managers need to ensure that pesticides that could harm aquatic organisms (including algae) not be used within close proximity to streams or storm drainages and that application timing should be considered for environmental protection.
Date:
October 6, 2003
Creator:
Campbell, C G; Folks, K; Mathews, S & Martinelli, R
Object Type:
Article
System:
The UNT Digital Library
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
Experimental Studies of Electron and Gas Sources in a Heavy-Ion Beam
None
Date:
October 12, 2004
Creator:
Molvik, A W; Cohen, R H; Friedman, A; Covo, M K; Lund, S M; Seidl, P A et al.
Object Type:
Article
System:
The UNT Digital Library
University of Wisconsin-Madison: Distributed Resources to Meet Demands of High-Value Power
Summarizes the University of Wisconsin-Madison's work under contract to DOE's Distribution and Interconnection R&D to demonstrate the value of distributed resources for high-value power.
Date:
October 1, 2003
Creator:
unknown
Object Type:
Text
System:
The UNT Digital Library
A Dynamically Adaptive Arbitrary Lagrangian-Eulerian Method for 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. The novel components of the combined ALE-AMR method hinge upon the integration of traditional AMR techniques with both staggered grid Lagrangian operators as well as elliptic relaxation operators on moving, deforming mesh hierarchies. Numerical examples demonstrate the utility of the method in performing detailed three-dimensional shock-driven instability calculations.
Date:
October 19, 2002
Creator:
Anderson, R W; Pember, R B & Elliott, N S
Object Type:
Article
System:
The UNT Digital Library
Development of Burning Plasma and Advanced Scenarios in the DIII-D Tokamak
Significant progress in the development of burning plasma scenarios, steady-state scenarios at high fusion performance, and basic tokamak physics has been made by the DIII-D Team. Discharges similar to the ITER baseline scenario have demonstrated normalized fusion performance nearly 50% higher than required for Q = 10 in ITER, under stationary conditions. Discharges that extrapolate to Q {approx} 10 for longer than one hour in ITER at reduced current have also been demonstrated in DIII-D under stationary conditions. Proof of high fusion performance with full noninductive operation has been obtained. Underlying this work are studies validating approaches to confinement extrapolation, disruption avoidance and mitigation, tritium retention, ELM avoidance, and operation above the no-wall pressure limit. In addition, the unique capabilities of the DIII-D facility have advanced studies of the sawtooth instability with unprecedented time and space resolution, threshold behavior in the electron heat transport, and rotation in plasmas in the absence of external torque.
Date:
October 18, 2004
Creator:
Luce, T C
Object Type:
Article
System:
The UNT Digital Library
Nuclear structure with accurate chiral perturbation theory nucleon-nucleon potential: Application to 6Li and 10B
The authors calculate properties of A = 6 system using the accurate charge-dependent nucleon-nucleon (NN) potential at fourth order of chiral perturbation theory. By application of the ab initio no-core shell model (NCSM) and a variational calculation in the harmonic oscillator basis with basis size up to 16 {h_bar}{Omega} they obtain the {sup 6}Li binding energy of 28.5(5) MeV and a converged excitation spectrum. Also, they calculate properties of {sup 10}B using the same NN potential in a basis space of up to 8 {h_bar}{Omega}. The results are consistent with results obtained by standard accurate NN potentials and demonstrate a deficiency of Hamiltonians consisting of only two-body terms. At this order of chiral perturbation theory three-body terms appear. It is expected that inclusion of such terms in the Hamiltonian will improve agreement with experiment.
Date:
October 14, 2003
Creator:
Navratil, P & Caurier, E
Object Type:
Report
System:
The UNT Digital Library
Crystal Level Continuum Modeling of Phase Transformations: The (alpha) <--> (epsilon) Transformation in Iron
We present a crystal level model for thermo-mechanical deformation with phase transformation capabilities. The model is formulated to allow for large pressures (on the order of the elastic moduli) and makes use of a multiplicative decomposition of the deformation gradient. Elastic and thermal lattice distortions are combined into a single lattice stretch to allow the model to be used in conjunction with general equation of state relationships. Phase transformations change the mass fractions of the material constituents. The driving force for phase transformations includes terms arising from mechanical work, from the temperature dependent chemical free energy change on transformation, and from interaction energy among the constituents. Deformation results from both these phase transformations and elasto-viscoplastic deformation of the constituents themselves. Simulation results are given for the {alpha} to {epsilon} phase transformation in iron. Results include simulations of shock induced transformation in single crystals and of compression of polycrystals. Results are compared to available experimental data.
Date:
October 18, 2004
Creator:
Barton, N R; Benson, D J; Becker, R; Bykov, Y & Caplan, M
Object Type:
Article
System:
The UNT Digital Library
Chemical Inhomogeneities and Pulsation
Major improvements in models of chemically peculiar stars have been achieved in the past few years. With these new models it has been possible to test quantitatively some of the processes involved in the formation of abundance anomalies and their effect on stellar structure. The models of metallic A (Am) stars have shown that a much deeper mixing has to be present to account for observed abundance anomalies. This has implications on their variability, which these models also reproduce qualitatively. These models also have implications for other chemically inhomogeneous stars such as HgMn B stars which are not known to be variable and {lambda} Booetis stars which can be. The study of the variability of chemically inhomogeneous stars can provide unique information on the dynamic processes occurring in many types of stars in addition to modeling of the evolution of their surface composition.
Date:
October 9, 2001
Creator:
Turcotte, S
Object Type:
Article
System:
The UNT Digital Library
Block Matching for Object Tracking
Models which describe road traffic patterns can be helpful in detection and/or prevention of uncommon and dangerous situations. Such models can be built by the use of motion detection algorithms applied to video data. Block matching is a standard technique for encoding motion in video compression algorithms. We explored the capabilities of the block matching algorithm when applied for object tracking. The goal of our experiments is two-fold: (1) to explore the abilities of the block matching algorithm on low resolution and low frame rate video and (2) to improve the motion detection performance by the use of different search techniques during the process of block matching. Our experiments showed that the block matching algorithm yields good object tracking results and can be used with high success on low resolution and low frame rate video data. We observed that different searching methods have small effect on the final results. In addition, we proposed a technique based on frame history, which successfully overcame false motion caused by small camera movements.
Date:
October 13, 2003
Creator:
Gyaourova, A; Kamath, C & Cheung, S
Object Type:
Report
System:
The UNT Digital Library
Determining the Equation of State Isentrope in an Isochoric Heated Plasma
A novel method for determining the equation-of-state (EOS) along the release isentrope in an isochoric (constant volume) heated plasma is presented. The sensitivity of this approach is demonstrated using two different equation-of-state models for a solid density, 10 eV expanding Al plasma. Determining the material EOS data is validated to pressures near 80 Mbar, much higher than current isentropic compression experiments allow. Limitations at high temperature (T{sub e} {ge} 100 eV) due to the formation of a radiative conduction layer near the rarefaction interface are also illustrated.
Date:
October 16, 2003
Creator:
Foord, M. E.; Reisman, D. B. & Springer, P. T.
Object Type:
Article
System:
The UNT Digital Library
APDS: The Autonomous Pathogen Detection System
We have developed and tested a fully autonomous pathogen detection system (APDS) capable of continuously monitoring the environment for airborne biological threat agents. The system was developed to provide early warning to civilians in the event of a bioterrorism incident and can be used at high profile events for short-term, intensive monitoring or in major public buildings or transportation nodes for long-term monitoring. The APDS is completely automated, offering continuous aerosol sampling, in-line sample preparation fluidics, multiplexed detection and identification immunoassays, and nucleic-acid based polymerase chain reaction (PCR) amplification and detection. Highly multiplexed antibody-based and duplex nucleic acid-based assays are combined to reduce false positives to a very low level, lower reagent costs, and significantly expand the detection capabilities of this biosensor. This article provides an overview of the current design and operation of the APDS. Certain sub-components of the ADPS are described in detail, including the aerosol collector, the automated sample preparation module that performs multiplexed immunoassays with confirmatory PCR, and the data monitoring and communications system. Data obtained from an APDS that operated continuously for seven days in a major U.S. transportation hub is reported.
Date:
October 4, 2004
Creator:
Hindson, Benjamin; Makarewicz, Anthony; Setlur, Ujwal; Henderer, Bruce; McBride, Mary & Dzenitis, John
Object Type:
Article
System:
The UNT Digital Library
Improved Energy Coupling into the Gain Region of the Ni-Like Pd Transient Collisional X-Ray Laser
We present within this paper a series of experiments, which yield new observations to further our understanding of the transient collisional x-ray laser medium. We use the recently developed technique of picosecond x-ray laser interferometry to probe the plasma conditions in which the x-ray laser is generated and propagates. This yields two dimensional electron density maps of the plasma taken at different times relative to the peak of the 600ps plasma-forming beam. In another experimental campaign, the output of the x-ray laser plasma column is imaged with a spherical multilayer mirror onto a CCD camera to give a two-dimensional intensity map of the x-ray laser output. Near-field imaging gives insights into refraction, output intensity and spatial mode structure. Combining these images with the density maps gives an indication of the electron density at which the x-ray laser is being emitted at (yielding insights into the effect of density gradients on beam propagation). Experimental observations coupled with simulations predict that most effective coupling of laser pump energy occurs when the duration of the main heating pulse is comparable to the gain lifetime ({approx}10ps for Ni-like schemes). This can increase the output intensity by more than an order of magnitude relative to …
Date:
October 5, 2004
Creator:
Smith, R.; Dunn, J.; Filevich, J.; Moon, S.; Nilsen, J.; Keenan, R. et al.
Object Type:
Article
System:
The UNT Digital Library
Multiple quantum and dipolar correlation effect NMR studies of cross-linking in elastomer systems
None
Date:
October 4, 2000
Creator:
Maxwell, R S & Balazs, B
Object Type:
Article
System:
The UNT Digital Library
Determination of collision rates relevant to Weibel-like instability growth rates in classical and non-classical plasmas encountered in fast-ignition experiments
Analytical simulations of fast-electron currents induced by high-density laser-plasma interactions require estimation of various plasma and beam parameters, including temperatures, densities, and collision rates. This note describes a technique used to estimate or calculate these parameters for the case of contemporary multi-terawatt experiments using foil targets as well as for anticipated fast-ignition-scale experiments.
Date:
October 18, 2004
Creator:
Hill, J M & Key, M H
Object Type:
Report
System:
The UNT Digital Library
Pump Selection Considerations
BestPractices Program tip sheet discussing pumping system efficiency with pumping selection considerations.
Date:
October 1, 2005
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Production LHC HTS power lead test results
The Fermilab Magnet test facility has built and operated a test stand to characterize the performance of HTS power leads. We report here the results of production tests of 20 pairs of 7.5 kA HTS power leads manufactured by industry for installation in feed boxes for the LHC Interaction Region quadrupole strings. Included are discussions of the thermal, electrical, and quench characteristics under ''standard'' and ''extreme'' operating conditions, and the stability of performance across thermal cycles.
Date:
October 1, 2004
Creator:
Tartaglia, M. A.; Carcagno, R. H.; Feher, S.; Huang, Y.; Orris, D. F.; Pischalnikov, Y. et al.
Object Type:
Article
System:
The UNT Digital Library
Timing is Everything:The Boon and Bane of 14C Geochronology
There are underappreciated limitations of the conversion of {sup 14}C-ages to the fixed, calendrical time-scale that bear directly upon our understanding of the dynamic climate system, or the relationship between the collapse of one civilization and it's neighbor's. In this paper we present a quantitative assessment of the limits of {sup 14}C-geochronology and calibration onto the absolute calendrical time-scale over the Holocene. We take into account not only the inherent limitations of the {sup 14}C-calendar calibration curve, but also analytical uncertainties.
Date:
October 29, 2004
Creator:
Guilderson, T; Guilderson, T; Reimer, P J & Brown, T
Object Type:
Article
System:
The UNT Digital Library
Implicit Monte Carlo diffusion - an acceleration method for Monte Carlo time dependent radiative transfer simulations
We present a method for accelerating time dependent Monte Carlo radiative transfer calculations by using a discretization of the diffusion equation to calculate probabilities that are used to advance particles in regions with small mean free path. The method is demonstrated on problems with on 1 and 2 dimensional orthogonal grids. It results in decreases in run time of more than an order of magnitude on these problems, while producing answers with accuracy comparable to pure IMC simulations. We call the method Implicit Monte Carlo Diffusion, which we abbreviate IMD.
Date:
October 1, 2000
Creator:
Gentile, N. A.
Object Type:
Article
System:
The UNT Digital Library
Evaluation of the Geothermal Public Power Utility Workshops in California
The federal government devotes significant resources to educating consumers and businesses about geothermal energy. Yet little evidence exists for defining the kinds of information needed by the various audiences with specialized needs. This paper presents the results of an evaluation of the Geothermal Municipal Utility Workshops that presented information on geothermal energy to utility resource planners at customer-owned utilities in California. The workshops were sponsored by the Western Area Power Administration and the U.S. Department of Energy's GeoPowering the West Program and were intended to qualitatively assess the information needs of municipal utilities relative to geothermal energy and get feedback for future workshops. The utility workshop participants found the geothermal workshops to be useful and effective for their purposes. An important insight from the workshops is that utilities need considerable lead-time to plan a geothermal project. They need to know whether it is better to own a project or to purchase geothermal electricity from another nonutility owner. California customer-owned utilities say they do not need to generate more electricity to meet demand, but they do need to provide more electricity from renewable resources to meet the requirements of the state's Renewable Portfolio Standard.
Date:
October 1, 2004
Creator:
Farhar, B. C.
Object Type:
Report
System:
The UNT Digital Library
Future Directions for Thermal Distribution Standards
This report details development paths for advanced versions of ASHRAE Standard 152, Method of Test for Determining the Design and Seasonal Efficiencies of Residential Thermal Distribution Efficiency. During the course of conversations within the ASHRAE committee responsible for developing the standard (SPC152P), three areas of development for Standard 152 were proposed: (1) extend the scope of the standard to include thermal comfort variables; (2) extend the scope of the standard to include small commercial buildings; and (3) improve the existing standard with respect to accuracy and economy of effort. Research needs associated with each of the three options are identified.
Date:
October 31, 2003
Creator:
Andrews, John W.
Object Type:
Report
System:
The UNT Digital Library
A neutron sensor based on synthetic single crystal diamond
We report the first neutron data for a single crystal Chemical Vapor Deposition (CVD) diamond sensor. Results are presented for 2.5, 14.1, and 14.9 MeV incident neutrons. We show that the energy resolution for 14.1 MeV neutrons is at least 2.9% (as limited by the energy spread of the incident neutrons), and perhaps as good as 0.4% (as extrapolated from high resolution {alpha} particle data). This result could be relevant to fusion neutron spectroscopy at machines like the International Thermonuclear Experimental Reactor (ITER). We also show that our sensor has a high neutron linear attenuation coefficient, due to the high atomic density of diamond, and this could lead to applications in fission neutron detection.
Date:
October 17, 2003
Creator:
Schmid, G. J.; Koch, J. A.; Lerche, R. A. & Moran, M. J.
Object Type:
Article
System:
The UNT Digital Library