A Piecewise Bi-Linear Discontinuous Finite Element Spatial Discretization of the Sn Transport Equation (open access)

A Piecewise Bi-Linear Discontinuous Finite Element Spatial Discretization of the Sn Transport Equation

We present a new spatial discretization of the discrete-ordinates transport equation in two-dimensional Cartesian (X-Y) geometry for arbitrary polygonal meshes. The discretization is a discontinuous finite element method (DFEM) that utilizes piecewise bi-linear (PWBL) basis functions, which are formally introduced in this paper. We also present a series of numerical results on quadrilateral and polygonal grids and compare these results to a variety of other spatial discretizations that have been shown to be successful on these grid types. Finally, we note that the properties of the PWBL basis functions are such that the leading-order piecewise bi-linear discontinuous finite element (PWBLD) solution will satisfy a reasonably accurate diffusion discretization in the thick diffusion limit, making the PWBLD method a viable candidate for many different classes of transport problems.
Date: December 22, 2010
Creator: Bailey, T S; Chang, J H; Warsa, J S & Adams, M L
Object Type: Article
System: The UNT Digital Library
Basin Analysis of the Mississippi Interior Salt Basin and Petroleum System Modeling of the Jurassic Smackover Formation, Eastern Gulf Coastal Plain (open access)

Basin Analysis of the Mississippi Interior Salt Basin and Petroleum System Modeling of the Jurassic Smackover Formation, Eastern Gulf Coastal Plain

This report provides a comprehensive analysis of the Mississippi interior salt basin and to transfer the results effectively.
Date: December 22, 1997
Creator: Mancini, Ernest A.
Object Type: Report
System: The UNT Digital Library
Statistical Exploration of Electronic Structure of Molecules from Quantum Monte-Carlo Simulations (open access)

Statistical Exploration of Electronic Structure of Molecules from Quantum Monte-Carlo Simulations

In this report, we present results from analysis of Quantum Monte Carlo (QMC) simulation data with the goal of determining internal structure of a 3N-dimensional phase space of an N-electron molecule. We are interested in mining the simulation data for patterns that might be indicative of the bond rearrangement as molecules change electronic states. We examined simulation output that tracks the positions of two coupled electrons in the singlet and triplet states of an H2 molecule. The electrons trace out a trajectory, which was analyzed with a number of statistical techniques. This project was intended to address the following scientific questions: (1) Do high-dimensional phase spaces characterizing electronic structure of molecules tend to cluster in any natural way? Do we see a change in clustering patterns as we explore different electronic states of the same molecule? (2) Since it is hard to understand the high-dimensional space of trajectories, can we project these trajectories to a lower dimensional subspace to gain a better understanding of patterns? (3) Do trajectories inherently lie in a lower-dimensional manifold? Can we recover that manifold? After extensive statistical analysis, we are now in a better position to respond to these questions. (1) We definitely see clustering …
Date: December 22, 2010
Creator: Prabhat, Mr.; Zubarev, Dmitry & Lester, William A., Jr.
Object Type: Report
System: The UNT Digital Library
2005 the North American Solar Challenge (open access)

2005 the North American Solar Challenge

In July 2005 the North American Solar Challenge (NASC) featured university built solar powered cars ran across the United States into Canada. The competition began in Austin, Texas with stops in Weatherford, Texas; Broken Arrow, Oklahoma; Topeka, Kansas; Omaha, Nebraska; Sioux Falls, South Dakota, Fargo, North Dakota; Winnipeg, Manitoba; Brandon, Manitoba; Regina, Saskatchewan; Medicine Hat, Alberta; mainly following U.S. Highway 75 and Canadian Highway 1 to the finish line in Calgary, Alberta, Canada, for a total distance of 2,500 miles. NASC major sponsors include the U.S. Department of Energy (DOE), Natural Resources Canada and DOEs National Renewable Energy Laboratory. The event is designed to inspire young people to pursue careers in science and engineering. NASCs predecessors, the American Solar Challenge and Sunrayce, generally have been held every two years since 1990. With each race, the solar cars travel faster and further with greater reliability. The NASC promotes: -Renewable energy technologies (specifically photovoltaic or solar cells) -Educational excellence in science, engineering and mathematics -Creative integration of technical and scientific expertise across a wide-range of disciplines -Hands-on experience for students and engineers to develop and demonstrate their technical and creative abilities. Safety is the first priority for the NASC. Each team put …
Date: December 22, 2008
Creator: Eberle, Dan
Object Type: Report
System: The UNT Digital Library
Removal of CDP Mandrels from Sputter Coated Beryllium Capsules for NIF Targets (open access)

Removal of CDP Mandrels from Sputter Coated Beryllium Capsules for NIF Targets

Ablative targets for the National Ignition Campaign (NIC) have been fabricated by sputter coating spherical mandrels made of glow discharge polymer (GDP) with graded copper doped beryllium (Be) layers. The inner mandrel must be completely removed to meet specific ignition design requirements. The process of removing the mandrel requires elevated temperature in the presence of oxygen. However, elevating the temperature in air also oxidizes the Be and can cause blistering on the inner surface of the Be shell. This paper will discuss a refined technique, which removes the GDP mandrel without compromising the integrity of the inner Be surface. The oxygen gradient that develops during the mandrel removal and the impact of its presence will also be discussed.
Date: December 22, 2006
Creator: Lawrence Livermore National Laboratory
Object Type: Article
System: The UNT Digital Library
Equation of State, Occupation Probabilities and Conductivities in the Average Atom Purgatorio Code (open access)

Equation of State, Occupation Probabilities and Conductivities in the Average Atom Purgatorio Code

We report on recent developments with the Purgatorio code, a new implementation of Liberman's Inferno model. This fully relativistic average atom code uses phase shift tracking and an efficient refinement scheme to provide an accurate description of continuum states. The resulting equations of state accurately represent the atomic shell-related features which are absent in Thomas-Fermi-based approaches. We discuss various representations of the exchange potential and some of the ambiguities in the choice of the effective charge Z* in average atom models, both of which affect predictions of electrical conductivities and radiative properties.
Date: December 22, 2006
Creator: Sterne, P
Object Type: Article
System: The UNT Digital Library
Performance Assessment of Disposal of Selected U.S. Department of Energy Spent Fuel in High Integrity Cans (open access)

Performance Assessment of Disposal of Selected U.S. Department of Energy Spent Fuel in High Integrity Cans

The purpose of this calculation is to determine the effects on long-term dose from disposing of selected U. S. Department of Energy (DOE) spent nuclear fuel (DSNF) in high integrity cans (HICs). The Civilian Radioactive Waste Management System Management and Operating contractor (CRWMS M&O) prepared the calculation as part of Performance Assessment (PA) activities for the DOE Yucca Mountain Project. DSNF encompasses approximately 2,500 MTHM (metric tons heavy metal) consisting of over 200 fuel types that have been categorized into 11 groups, referred to as Groups 1 to 11, to facilitate their performance assessment (DOE 1999a, Sec. 5). DSNF and high level waste (HLW) have been allocated 7,000 MTHM or 10% of the 70,000 MTHM of nuclear waste scheduled for disposal at Yucca Mountain (DOE 1999a, Sec. 8.1). Of the 7,000 MTHM, 2,333 will be DSNF, or 93% of all 2,500 MTHM of DSNF, and 4,667 MTHM equivalent will be HLW (DOE 1999a, Sec. 8.1). The DOE spent fuels selected for HIC disposal are those that are poorly characterized, fragmented, or damaged, and the HIC concept is intended to provide additional protection by delaying the radionuclide release to ensure that environmental and/or regulatory standards are met.
Date: December 22, 2000
Creator: Saulnier, G. J., Jr.
Object Type: Report
System: The UNT Digital Library
Material-dependent high-frequency current fluctuations of cathodicvacuum arcs: Evidence for the ecton cutoff of the fractal model (open access)

Material-dependent high-frequency current fluctuations of cathodicvacuum arcs: Evidence for the ecton cutoff of the fractal model

Current fluctuations of cathodic arcs were recorded withhigh analog bandwidth (up to 1 GHz) and fast digital sampling (up to 5Gsamples/sec). The power spectral density of the arc current wasdetermined by fast Fourier transform clearly showing material dependent,non-linear features in the frequency domain. These features can beassociated with the non-linear impedance of the conducting channelbetween cathode and anode, driven by the explosive nature of electronemission and plasma formation. The characteristic times of less than 100ns can be associated with individual explosive processes, "ectons," andtherefore represent the short-time physical cutoff for the fractal modelof cathodic arcs.
Date: December 22, 2005
Creator: Anders, Andre & Oks, Efim
Object Type: Article
System: The UNT Digital Library
Analytical and Numerical Ray Tracing of X-Ray Lasers (open access)

Analytical and Numerical Ray Tracing of X-Ray Lasers

Soft x-ray lasers in 10-30nm range are now routinely produced in hot plasmas generated either by a laser from a solid target or by an electrical discharge in a capillary. Such an x-ray laser is a convenient tool for future applications, such as probing dense plasmas of interest for fusion experiments. Their short wavelength enables plasma diagnosis beyond the capabilities of optical lasers, because the high critical plasma density ({approx}{lambda}{sup 2}) limits the optical beam propagation. In our paper, we present analytical and numerical ray tracing of an x-ray laser in dense amplifying plasmas. A general analytical formula for a beam propagation has been developed for a gradient plasma. The simplified analytical formulaes enable better understanding of processes involved. They also simplify optimization of the beam propagation and ''mapping'' the parameter space for further studies by numerical codes. We discuss implications for a transient x-ray laser that is produced from a slab target by a (sub-)picosecond laser pulse.
Date: December 22, 2003
Creator: Kuba, J; Shlyaptsev, V N; Benredjem, D & Moller, C
Object Type: Article
System: The UNT Digital Library
Linear and nonlinear Rayleigh-Taylor growth at strongly convergent spherical interfaces (open access)

Linear and nonlinear Rayleigh-Taylor growth at strongly convergent spherical interfaces

Recent attention has focused on the effect of spherical convergence on the nonlinear phase of Rayleigh-Taylor growth. For instability growth on spherically converging interfaces, modifications to the predictions of the Layzer model for the secular growth of a single, nonlinear mode have been reported [D. S. Clark and M. Tabak, Phys. Rev. E 72, 0056308 (2005).]. However, this model is limited in assuming a self-similar background implosion history as well as only addressing growth from a perturbation of already nonlinearly large amplitude. Additionally, only the case of single-mode growth was considered and not the multimode growth of interest in applications. Here, these deficiencies are remedied. First, the connection of the recent nonlinear results including convergence to the well-known results for the linear regime of growth is demonstrated. Second, the applicability of the model to more general implosion histories (i.e., not self-similar) is shown. Finally, to address the case of multimode growth with convergence, the recent nonlinear single mode results are combined with the Haan model formulation for weakly nonlinear multimode growth. Remarkably, convergence in the nonlinear regime is found not to modify substantially the multimode predictions of Haan's original model.
Date: December 22, 2005
Creator: Clark, D S & Tabak, M
Object Type: Article
System: The UNT Digital Library
Fluidized Bed Steam Reformer Monolith Formation (open access)

Fluidized Bed Steam Reformer Monolith Formation

Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or ''mineralized'' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydroceramics. All but one of the nine monoliths tested met the <2g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; …
Date: December 22, 2006
Creator: Jantzen, Carol M.
Object Type: Article
System: The UNT Digital Library
Demonstration of Smart Building Controls to Manage Building Peak Loads: Innovative Non-Wires Technologies (open access)

Demonstration of Smart Building Controls to Manage Building Peak Loads: Innovative Non-Wires Technologies

As a part of the non-wires solutions effort, BPA in partnership with Pacific Northwest National Laboratory (PNNL) is exploring the use of two distributed energy resources (DER) technologies in the City of Richland. In addition to demonstrating the usefulness of the two DER technologies in providing peak demand relief, evaluation of remote direct load control (DLC) is also one of the primary objectives of this demonstration. The concept of DLC, which is used to change the energy use profile during peak hours of the day, is not new. Many utilities have had success in reducing demand at peak times to avoid building new generation. It is not the need for increased generation that is driving the use of direct load control in the Northwest, but the desire to avoid building additional transmission capacity. The peak times at issue total between 50 and 100 hours a year. A transmission solution to the problem would cost tens of millions of dollars . And since a ?non wires? solution is just as effective and yet costs much less, the capital dollars for construction can be used elsewhere on the grid where building new transmission is the only alternative. If by using DLC, the …
Date: December 22, 2004
Creator: Katipamula, Srinivas & Hatley, Darrel D.
Object Type: Report
System: The UNT Digital Library
TRANSPORTATION SYSTEM REQUIREMENTS DOCUMENT (open access)

TRANSPORTATION SYSTEM REQUIREMENTS DOCUMENT

None
Date: December 22, 2004
Creator: /a, n
Object Type: Report
System: The UNT Digital Library
Community Resilience: Workshops on Private Sector and Property Owner Requirements for Recovery and Restoration from a Diasaster (open access)

Community Resilience: Workshops on Private Sector and Property Owner Requirements for Recovery and Restoration from a Diasaster

This report summarizes the results of a proejct sponsored by DTRA to 1) Assess the readiness of private-sector businesses, building owners, and service providers to restore property and recover operations in the aftermath of a wide-area dispersal of anthrax; and 2) Understand what private property owners and businesses "want and need" from federal, state, and local government to support recovery and restoration from such an incident.
Date: December 22, 2008
Creator: Judd, Kathleen S.; Stein, Steven L. & Lesperance, Ann M.
Object Type: Report
System: The UNT Digital Library
Extreme Scaling of Production Visualization Software on Diverse Architectures (open access)

Extreme Scaling of Production Visualization Software on Diverse Architectures

We present the results of a series of experiments studying how visualization software scales to massive data sets. Although several paradigms exist for processing large data, we focus on pure parallelism, the dominant approach for production software. These experiments utilized multiple visualization algorithms and were run on multiple architectures. Two types of experiments were performed. For the first, we examined performance at massive scale: 16,000 or more cores and one trillion or more cells. For the second, we studied weak scaling performance. These experiments were performed on the largest data set sizes published to date in visualization literature, and the findings on scaling characteristics and bottlenecks contribute to understanding of how pure parallelism will perform at high levels of concurrency and with very large data sets.
Date: December 22, 2009
Creator: Childs, Henry; Pugmire, David; Ahern, Sean; Whitlock, Brad; Howison, Mark; Weber, Gunther et al.
Object Type: Article
System: The UNT Digital Library
Reaction of the C2H radical with 1-butyne (C4H6): Low Temperature Kinetics and Isomer-Specific Product Detection (open access)

Reaction of the C2H radical with 1-butyne (C4H6): Low Temperature Kinetics and Isomer-Specific Product Detection

The rate coefficient for the reaction of the ethynyl radical (C{sub 2}H) with 1-butyne (H-C{triple_bond}C-CH{sub 2}-CH{sub 3}) is measured in a pulsed Laval nozzle apparatus. Ethynyl radicals are formed by laser photolysis of acetylene (C{sub 2}H{sub 2}) at 193 nm and detected via chemiluminescence (C{sub 2}H + O{sub 2} {yields} CH (A{sup 2}{Delta}) + CO{sub 2}). The rate coefficients are measured over the temperature range of 74-295 K. The C{sub 2}H + 1-butyne reaction exhibits no barrier and occurs with rate constants close to the collision limit. The temperature dependent rate coefficients can be fit within experimental uncertainties by the expression k = (2.4 {+-} 0.5) x 10{sup -10} (T/295 K)-(0.04 {+-} 0.03) cm{sup 3} molecule{sup -1}s{sup -1}. Reaction products are detected at room temperature (295 K) and 533 Pa using a Multiplexed Photoionization Mass Spectrometer (MPIMS) coupled to the tunable VUV synchrotron radiation from the Advanced Light Source at the Lawrence Berkeley National Laboratory. Two product channels are identified for this reaction: m/z = 64 (C{sub 5}H{sub 4}) and m/z = 78 (C{sub 6}H{sub 6}) corresponding to the CH{sub 3}- and H-loss channels, respectively. Photoionization efficiency (PIE) curves are used to analyze the isomeric composition of both product channels. …
Date: December 22, 2009
Creator: Soorkia, Satchin; Trevitt, Adam J.; Selby, Talitha M.; Osborn, David L.; Taatjes, Craig A.; Wilson, Kevin R. et al.
Object Type: Article
System: The UNT Digital Library
Development of a Brazing Process for Sealing Instrumentation Leads Using a Lithium Bearing Braze Alloy (open access)

Development of a Brazing Process for Sealing Instrumentation Leads Using a Lithium Bearing Braze Alloy

This report describes the development qualification and application of brazing process that eliminates the gold plating operation and the supplementary inlay brazing operation without effecting any of he several constraints that the application places on any seal brazing process developed.
Date: December 22, 1964
Creator: Laughner, E.M.
Object Type: Report
System: The UNT Digital Library
Pilot Plant Preparation of Thorium and Thorium-Uranium Oxides (open access)

Pilot Plant Preparation of Thorium and Thorium-Uranium Oxides

Thorium oxide is formed by the calcination of thorium oxalate precipitated under carefully controlled conditions. Material is produced with mean particle diameters of 1 to 5 mu . Some of the thorium oxide had uranium added to it by decomposing uranyl carbonate on the thorium oxide followed by calcination. Most of the oxides prepared were calcined to 1000 deg C or more and size classified to remove particles greater than 10 mu . The oxides were prepared in 150-lb batches, with a complete cycle requiring 24 hr. (auth)
Date: December 22, 1959
Creator: Johnsson, K. O. & Winget, R. H.
Object Type: Report
System: The UNT Digital Library
Laser modulated scattering as a nondestructive evaluation tool for optical surfaces and thin film coatings (open access)

Laser modulated scattering as a nondestructive evaluation tool for optical surfaces and thin film coatings

Laser modulated scattering (LMS) is introduced as a non-destructive evaluation tool for defect inspection and characterization of optical surfaces and thin film coatings. This technique is a scatter sensitive version of the well-known photothermal microscopy (PTM) technique. It allows simultaneous measurement of the DC and AC scattering signals of a probe laser beam from an optical surface. By comparison between the DC and AC scattering signals, one can differentiate absorptive defects from non-absorptive ones. This paper describes the principle of the LMS technique and the experimental setup, and illustrates examples on using LMS as a tool for nondestructive evaluation of high quality optics.
Date: December 22, 1999
Creator: Feit, M D; Kozlowski, M R; Rubenchik, A M; Sheehan, L & Wu, Z L
Object Type: Article
System: The UNT Digital Library
Airfare and Catering Costs in Support of Panelists Attendance at Panel (open access)

Airfare and Catering Costs in Support of Panelists Attendance at Panel

Panelist attendance at the National Science Foundation Plasma Panel.
Date: December 22, 2003
Creator: McKnight, R.
Object Type: Report
System: The UNT Digital Library
A COMPUTATIONAL WORKBENCH ENVIRONMENT FOR VIRTUAL POWER PLANT SIMULATION (open access)

A COMPUTATIONAL WORKBENCH ENVIRONMENT FOR VIRTUAL POWER PLANT SIMULATION

In this report is described the work effort to develop and demonstrate a software framework to support advanced process simulations to evaluate the performance of advanced power systems. Integrated into the framework are a broad range of models, analysis tools, and visualization methods that can be used for the plant evaluation. The framework provides a tightly integrated problem-solving environment, with plug-and-play functionality, and includes a hierarchy of models, ranging from fast running process models to detailed reacting CFD models. The framework places no inherent limitations on the type of physics that can be modeled, numerical techniques, or programming languages used to implement the equipment models, or the type or amount of data that can be exchanged between models. Tools are provided to analyze simulation results at multiple levels of detail, ranging from simple tabular outputs to advanced solution visualization methods. All models and tools communicate in a seamless manner. The framework can be coupled to other software frameworks that provide different modeling capabilities. Three software frameworks were developed during the course of the project. The first framework focused on simulating the performance of the DOE Low Emissions Boiler System Proof of Concept facility, an advanced pulverized-coal combustion-based power plant. The …
Date: December 22, 2004
Creator: Bockelie, Mike; Swensen, Dave; Denison, Martin; Sarofim, Adel & Senior, Connie
Object Type: Report
System: The UNT Digital Library
Princeton Plasma Physics Laboratory Annual Site Environmental Report for Calendar Years 2002 and 2003 (open access)

Princeton Plasma Physics Laboratory Annual Site Environmental Report for Calendar Years 2002 and 2003

This report provides the U.S. Department of Energy (DOE) and the public with information on the level of radioactive and non-radioactive pollutants (if any) that are added to the environment as a result of Princeton Plasma Physics Laboratory's (PPPL) operations. The results of the 2002 and 2003 environmental surveillance and monitoring program for PPPL are presented and discussed. The report also summarizes environmental initiatives, assessments, and programs that were undertaken in 2002 and 2003.
Date: December 22, 2004
Creator: Virginia L. Finley, Editor
Object Type: Report
System: The UNT Digital Library
High strength and heat resistant chromium steels for sodium-cooled fast reactors. (open access)

High strength and heat resistant chromium steels for sodium-cooled fast reactors.

This report provides the results of a preliminary phase of a project supporting the Advanced Nuclear Fuel Cycle Technology Initiative at ANL. The project targets the Generation IV nuclear energy systems, particularly the area of reducing the cost of sodium-cooled fast-reactors by utilizing innovative materials. The main goal of the project is to provide the nuclear heat exchanger designers a simplified means to quantify the cost advantages of the recently developed high strength and heat resistant ferritic steels with 9 to 13% chromium content. The emphasis in the preliminary phase is on two steels that show distinctive advantages and have been proposed as candidate materials for heat exchangers and also for reactor vessels and near-core components of Gen IV reactors. These steels are the 12Cr-2W (HCM12A) and 9Cr-1MoVNb (modified 9Cr-1Mo). When these steels are in tube form, they are referred to in ASTM Standards as T122 and T91, respectively. A simple thermal-hydraulics analytical model of a counter-flow, shell-and-tube, once-through type superheated steam generator is developed to determine the required tube length and tube wall temperature profile. The single-tube model calculations are then extended to cover the following design criteria: (i) ratio of the tube stress due to water/steam pressure to …
Date: December 22, 2004
Creator: Kamal, S.; Grandy, C.; Farmer, M. & Brunsvold, A.
Object Type: Report
System: The UNT Digital Library
Abstraction of Bdcf Distributions for Irrigation Periods (open access)

Abstraction of Bdcf Distributions for Irrigation Periods

None
Date: December 22, 2000
Creator: Smith, A. J.
Object Type: Report
System: The UNT Digital Library