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Generalized b-spline subdivision-surface wavelets and lossless compression (open access)

Generalized b-spline subdivision-surface wavelets and lossless compression

We present a new construction of wavelets on arbitrary two-manifold topology for geometry compression. The constructed wavelets generalize symmetric tensor product wavelets with associated B-spline scaling functions to irregular polygonal base mesh domains. The wavelets and scaling functions are tensor products almost everywhere, except in the neighborhoods of some extraordinary points (points of valence unequal four) in the base mesh that defines the topology. The compression of arbitrary polygonal meshes representing isosurfaces of scalar-valued trivariate functions is a primary application. The main contribution of this paper is the generalization of lifted symmetric tensor product B-spline wavelets to two-manifold geometries. Surfaces composed of B-spline patches can easily be converted to this scheme. We present a lossless compression method for geometries with or without associated functions like color, texture, or normals. The new wavelet transform is highly efficient and can represent surfaces at any level of resolution with high degrees of continuity, except at a finite number of extraordinary points in the base mesh. In the neighborhoods of these points detail can be added to the surface to approximate any degree of continuity.
Date: November 24, 1999
Creator: Bertram, M; Duchaineau, M A; Hamann, B & Joy, K I
System: The UNT Digital Library
High precision electron beam diagnostic system for high current long pulse beams (open access)

High precision electron beam diagnostic system for high current long pulse beams

As part of the effort to develop a multi-axis electron beam transport system using stripline kicker technology for DARHT II apploications, it is necessary to precisely determine the position and extent of long high energy beams (6-40 MeV, 1-4 kA, 2 microseconds) for accurate position control. The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (<20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt measurements performed using capacitive pickoff probes. Likewise, transmission line traveling wave probes have problems with multi-bounce effects due to these longer pulse widths. Finally, the high energy densities experienced in these applications distort typical foil beam position measurements.
Date: March 24, 1999
Creator: Nelson, S. D.; Fessenden, T.; Chen, Y. J.; Holmes, C. & Selchow, N.
System: The UNT Digital Library
Hugoniots of aerogels involving carbon and resorcinol formaldehyde (open access)

Hugoniots of aerogels involving carbon and resorcinol formaldehyde

Recently, a first-order phase transition is predicted in liquid carbon using atomistic simulation and Brenner's bond order potential. There are also experimental data suggesting a possibility for a first-order phase transition. In light of this, a thermochemical equilibrium code (CHEQ) is used to provide guidance to experiments to find a liquid-liquid phase change in carbon foam and carbon-rich aerogel, resorcinol formaldehyde. Isotherms and Hugoniots were computed based on the previous analysis by van Thiel and Ree. The present calculations predict the liquid-liquid-graphite triple point to be at 5000 K and 5.2 GPa and its critical point to be at 6000 K and 8.8 GPa. The present Hugoniot calculations suggest that the liquid-liquid phase transition may be detected by performing a shock experiment with initial density of approximately 0.15 gm/cm{sup 3}.
Date: June 24, 1999
Creator: Hrubesh, L H; Ree, F H; Schmidt, R D; Shon, J; Van Thiel, M; Vantine, H C et al.
System: The UNT Digital Library
DARHT2 X-ray converter target system comparison (open access)

DARHT2 X-ray converter target system comparison

Four short current pulses with various pulse widths and spacing will be delivered to the x-ray converter target on the second-axis of the Dual-Axis Radiographic Hydrodynamic Test (DARHT-II) facility. To ensure that the DARHT-II multi-pulse target will provide enough target material for x-ray production for all four pulses, the target needs either to survive the strike of four electron pulses or to accommodate target replenishment. A distributed target may survive hitting of four electron pulses. For target replenishment, two types of target configurations are being considered: stationary target systems with beam repositioning and dynamic moving target systems. They compare these three target systems and their radiographic performance.
Date: March 24, 1999
Creator: Bergstrom, P. M.; Caporaso, G. J.; Chen, Y. J.; Ho, D. D.; McCarrick, J. F.; Pincosy, P. A. et al.
System: The UNT Digital Library
Modeling Multiple Causes of Carcinogenesis (open access)

Modeling Multiple Causes of Carcinogenesis

An array of epidemiological results and databases on test animal indicate that risk of cancer and atherosclerosis can be up- or down-regulated by diet through a range of 200%. Other factors contribute incrementally and include the natural terrestrial environment and various human activities that jointly produce complex exposures to endotoxin-producing microorganisms, ionizing radiations, and chemicals. Ordinary personal habits and simple physical irritants have been demonstrated to affect the immune response and risk of disease. There tends to be poor statistical correlation of long-term risk with single agent exposures incurred throughout working careers. However, Agency recommendations for control of hazardous exposures to humans has been substance-specific instead of contextually realistic even though there is consistent evidence for common mechanisms of toxicological and carcinogenic action. That behavior seems to be best explained by molecular stresses from cellular oxygen metabolism and phagocytosis of antigenic invasion as well as breakdown of normal metabolic compounds associated with homeostatic- and injury-related renewal of cells. There is continually mounting evidence that marrow stroma, comprised largely of monocyte-macrophages and fibroblasts, is important to phagocytic and cytokinetic response, but the complex action of the immune process is difficult to infer from first-principle logic or biomarkers of toxic injury. The …
Date: January 24, 1999
Creator: Jones, T.D.
System: The UNT Digital Library
Thermal Fusing Model of Conducting Particle Composites (open access)

Thermal Fusing Model of Conducting Particle Composites

Composites of carbon black particles in polyethylene are known to exhibit an unusually rapid increase in resistivity as the applied field is increased, making this material useful in automatically resettable fuses. In this application the composite is in series with the circuit it is protecting: at low applied voltages this circuit is the load, but at high applied voltages the composite becomes the load, limiting the current to the circuit. We present a simple model of this behavior in terms of a network of nonlinear conductors. Each conductor has a conductance that depends on its instantaneous Joule heating. It is shown that in the fusing regime, where the current through the composite decreases with increasing voltage, an plate-like dissipation instability develops normal to the applied field. Experimental evidence of this phenomena is described.
Date: June 24, 1999
Creator: Martin, James E.
System: The UNT Digital Library
FANTM: The First Article NIF Test Module for the Laser Power Conditioning System (open access)

FANTM: The First Article NIF Test Module for the Laser Power Conditioning System

Designing and developing the 1.7 to 2. 1-MJ Power Conditioning System (PCS) that powers the flashlamps for the National Ignition Facility (NIF), currently being constructed at Lawrence Livermore National Labs (LLNL), is one of several responsibilities assumed by Sandia National Labs (SNL) in support of the NIF Project. The test facility that has evolved over the last three years to satisfy the project requirements is called FANTM. It was built at SNL and has operated for about 17,000 shots to demonstrate component performance expectations over the lifetime of NIF. A few modules similar to the one shown in Fig. 1 will be used initially in the amplifier test phase of the project. The final till NIF system will require 192 of them (48 in each of four capacitor bays). This paper briefly summarizes the final design of the FANTM facility and compares its performance with the predictions of circuit simulations for both normal operation and fault-mode response. Applying both the measured and modeled power pulse waveforms as input to a physics-based, semi-empirical amplifier gain code indicates that the 20-capacitor PCS can satisfy the NIF requirement for an average gain coefficient of 5.00 %/cm and can exceed 5.20%/cm with 24 capacitors.
Date: June 24, 1999
Creator: Hammon, Jud; Harjes, Henry C.; Moore, William B.S.; Smith, David L. & Wilson, J. Michael
System: The UNT Digital Library
Final state interaction phase in B decays (open access)

Final state interaction phase in B decays

From an estimate of the meson-meson inelastic scattering at 5 GeV it is concluded that a typical strong phase in B decays to two mesons is of order of 20{sup o}. For a particular final state an estimate of the phase depends on whether that state is more or less probable as a final state compared to those states to which it is connected by the strong interaction S matrix.
Date: March 24, 1999
Creator: Suzuki, Mahiko & Wolfenstein, Lincoln
System: The UNT Digital Library
Anisotropic Magnetism in Field-Structured Composites (open access)

Anisotropic Magnetism in Field-Structured Composites

Magnetic field-structured-composites (FSCs) are made by structuring magnetic particle suspensions in uniaxial or biaxial (e.g. rotating) magnetic fields, while polymerizing the suspending resin. A uniaxial field produces chain-like particle structures, and a biaxial field produces sheet-like particle structures. In either case, these anisotropic structures affect the measured magnetic hysteresis loops, with the magnetic remanence and susceptibility increased significantly along the axis of the structuring field, and decreased slightly orthogonal to the structuring field, relative to the unstructured particle composite. The coercivity is essentially unaffected by structuring. We present data for FSCs of magnetically soft particles, and demonstrate that the altered magnetism can be accounted for by considering the large local fields that occur in FSCs. FSCS of magnetically hard particles show unexpectedly large anisotropies in the remanence, and this is due to the local field effects in combination with the large crystalline anisotropy of this material.
Date: June 24, 1999
Creator: Anderson, Robert A.; Martin, James E.; Odinek, Judy & Venturini, Eugene
System: The UNT Digital Library
Nonlinear Interlayer Tunneling in a Double Electron Layer Structure (open access)

Nonlinear Interlayer Tunneling in a Double Electron Layer Structure

None
Date: June 24, 1999
Creator: Lyo, S.K.
System: The UNT Digital Library
Use of Surfactant Micelles to Control the Structural Phase of Nanosize Iron Clusters (open access)

Use of Surfactant Micelles to Control the Structural Phase of Nanosize Iron Clusters

None
Date: June 24, 1999
Creator: Provencio, P. P. & Wilcoxon, J. P.
System: The UNT Digital Library
Transformation Mechanism and Kinetics for the Pressure-Induced Phase Transition in Shocked CdS (open access)

Transformation Mechanism and Kinetics for the Pressure-Induced Phase Transition in Shocked CdS

The pressure-induced phase transition in CdS was investigated using picosecond time-resolved electronic spectroscopy in plate impact shock wave experiments. Real-time changes in the electronic spectra were observed, with 100 ps time resolution, in single crystals of CdS shocked along the c and a axes to peak stresses between 35 and 90 kbar (above the phase transition stress of approximately 30 kbar measured in continuum studies). When shocked to stresses above approximately 50 kbar along the crystal c axis and 60 to 70 kbar along the crystal a axis, the crystals undergo a very rapid change in electronic structure, indicating that significant structural changes occur within the first 100 ps. These results, along with previous ns continuum measurements, make a strong case for a metastable state during the phase transition in shocked CdS. Ab-initio periodic Hartree-Fock calculations (with DFT correlation corrections) were employed to examine the compression of CdS and to determine a possible lattice structure for the proposed metastable structure. These results, along with details of the transformation kinetics and orientational dependence, will be discussed. Work supported by ONR.
Date: June 24, 1999
Creator: Gupta, Y.M.; Knudson, M.D. & Kunz, A.B.
System: The UNT Digital Library
Large-Scale Eigenvalue Calculations for Stability Analysis of Steady Flows on Massively Parallel Computers (open access)

Large-Scale Eigenvalue Calculations for Stability Analysis of Steady Flows on Massively Parallel Computers

None
Date: June 24, 1999
Creator: Lehoucq, Richard B. & Salinger, Andrew G.
System: The UNT Digital Library
Magnetic field generation from Self-Consistent collective neutrino-plasma interactions (open access)

Magnetic field generation from Self-Consistent collective neutrino-plasma interactions

A new Lagrangian formalism for self-consistent collective neutrino-plasma interactions is presented in which each neutrino species is described as a classical ideal fluid. The neutrino-plasma fluid equations are derived from a covariant relativistic variational principle in which finite-temperature effects are retained. This new formalism is then used to investigate the generation of magnetic fields and the production of magnetic helicity as a result of collective neutrino-plasma interactions.
Date: November 24, 1999
Creator: Brizard, A. J.; Murayama, H. & Wurtele, J. S.
System: The UNT Digital Library
Performance Characteristics of an Extended Throat Flow Nozzle for the Measurement of High Void Fraction Multi-Phase Flows (open access)

Performance Characteristics of an Extended Throat Flow Nozzle for the Measurement of High Void Fraction Multi-Phase Flows

An extended throat flow nozzle has been examined as a device for the measurement of very high void fraction multi-phase flows. Due to its greater density and partial contact with the wall, the equilibrium velocity of the liquid phase appreciably lags that of the lighter gas phase. The two phases are strongly coupled resulting in pressure drops across the contraction and in the extended throat that are significantly different than those experienced in single-phase flow. Information about the mass flow rates of the two phases can be extracted from the measured pressure drops. The performance of an extended throat flow nozzle has been evaluated under multi-phase conditions using natural gas and hydrocarbon liquids at 400 and 500 psi. Two hydrocarbon solvents were used as the test liquids, Isopar M (sp=0.79) and Aromatic 100 (sp=0.87). These data are compared to prior air-water data at nominally 15 psi. The high and low pressure data were found to be consistent, confirming that the temperature, pressure, and size scaling of the extended throat venturi are correctly represented. This consistency allows different sized devices to be applied under different fluid conditions (temperature, pressure, gas and liquid phase composition, etc) with confidence.
Date: March 24, 1999
Creator: Fincke, James R. (INEEL), Ronnenkamp, C.; Kruse, D.; Krogue, J. & Householder, D. (Perry Equipment Corporation)
System: The UNT Digital Library
Solid State Experiments at High Pressure and Strain Rates (open access)

Solid State Experiments at High Pressure and Strain Rates

Experiments have been developed using high powered laser facilities to study the response of materials in the solid state under extreme pressures and strain rates. Details of the target and drive development required for solid state experiments and results from two separate experiments are presented. In the first, thin foils were compressed to a peak pressure of 180 GPa and accelerated. A pre-imposed modulation at the embedded RT unstable interface was observed to grow. The growth rates were fluid-like at early time, but suppressed at later time. This result is suggestive of the theory of localized heating in shear bands, followed by dissipation of the heat, allowing for recovery of the bulk material strength. In the second experiment, the response of Si was studied by dynamic x-ray diffraction. The crystal was observed to respond with uni-axial compression at a peak pressure 11.5-13.5 GPa.
Date: November 24, 1999
Creator: Kalantar, D. H.; Remington, B. A.; Colvin, J. D.; Mikaelian, K. O.; Weber, S. V.; Wiley, L. G. et al.
System: The UNT Digital Library
Observation of Localized Corrosion of Ni-Based Alloys Using Coupled Orientation Imaging Microscopy and Atomic Force Microscopy (open access)

Observation of Localized Corrosion of Ni-Based Alloys Using Coupled Orientation Imaging Microscopy and Atomic Force Microscopy

We present a method for assessing the relative vulnerabilities of distinct classes of grain boundaries to localized corrosion. Orientation imaging microscopy provides a spatial map which identifies and classifies grain boundaries at a metal surface. Once the microstructure of a region of a sample surface has been characterized, a sample can be exposed to repeated cycles of exposure to a corrosive environment alternating with topographic measurement by an atomic force microscope in the same region in which the microstructure had been mapped. When this procedure is applied to Ni and Ni-based alloys, we observe enhanced attack at random grain boundaries relative to special boundaries and twins in a variety of environments.
Date: November 24, 1999
Creator: Bedrossian, P. J.
System: The UNT Digital Library
NRC-BNL Benchmark Program on Evaluation of Methods for Seismic Analysis of Coupled Systems (open access)

NRC-BNL Benchmark Program on Evaluation of Methods for Seismic Analysis of Coupled Systems

A NRC-BNL benchmark program for evaluation of state-of-the-art analysis methods and computer programs for seismic analysis of coupled structures with non-classical damping is described. The program includes a series of benchmarking problems designed to investigate various aspects of complexities, applications and limitations associated with methods for analysis of non-classically damped structures. Discussions are provided on the benchmarking process, benchmark structural models, and the evaluation approach, as well as benchmarking ground rules. It is expected that the findings and insights, as well as recommendations from this program will be useful in developing new acceptance criteria and providing guidance for future regulatory activities involving licensing applications of these alternate methods to coupled systems.
Date: March 24, 1999
Creator: Chokshi, N.; DeGrassi, G. & Xu, J.
System: The UNT Digital Library
Discontinuous Galerkin for Hyperbolic Systems with Stiff Relaxation (open access)

Discontinuous Galerkin for Hyperbolic Systems with Stiff Relaxation

A Discontinuous Galerkin method is applied to hyperbolic systems that contain stiff relaxation terms. We demonstrate that when the relaxation time is unresolved, the method is accurate in the sense that it accurately represents the system's Chapman-Enskog approximation. Results are presented for the hyperbolic heat equation and coupled radiation-hydrodynamics.
Date: May 24, 1999
Creator: Lowrie, Robert B. & Morel, Jim E.
System: The UNT Digital Library
Distributed control of protein crystallography beamline 5.0 using CORBA (open access)

Distributed control of protein crystallography beamline 5.0 using CORBA

The Protein Crystallography Beamline at Berkeley Lab's Advanced Light Source is a facility that is being used to solve the structure of proteins. The software that is being used to control this beamline uses Java for user interface applications which communicate via CORBA with workstations that control the beamline hardware. We describe the software architecture for the beamline and our experiences after two years of operation.
Date: September 24, 1999
Creator: Timossi, Chris
System: The UNT Digital Library
CURRENT STATUS OF VHE ASTRONOMY (open access)

CURRENT STATUS OF VHE ASTRONOMY

None
Date: June 24, 1999
Creator: SINNIS, G.
System: The UNT Digital Library
Workshop on the preparation of climate change action plans. Workshop summary (open access)

Workshop on the preparation of climate change action plans. Workshop summary

Over 130 participants from more than 27 countries shared experiences of developing and transition countries in preparation and development of their climate change national action plans. International experts guided countries in preparation of their climate change national action plans.
Date: May 24, 1999
Creator: unknown
System: The UNT Digital Library
Hanford Site waste treatment/storage/disposal integration (open access)

Hanford Site waste treatment/storage/disposal integration

In 1998 Waste Management Federal Services of Hanford, Inc. began the integration of all low-level waste, mixed waste, and TRU waste-generating activities across the Hanford site. With seven contractors, dozens of generating units, and hundreds of waste streams, integration was necessary to provide acute waste forecasting and planning for future treatment activities. This integration effort provides disposition maps that account for waste from generation, through processing, treatment and final waste disposal. The integration effort covers generating facilities from the present through the life-cycle, including transition and deactivation. The effort is patterned after the very successful DOE Complex EM Integration effort. Although still in the preliminary stages, the comprehensive onsite integration effort has already reaped benefits. These include identifying significant waste streams that had not been forecast, identifying opportunities for consolidating activities and services to accelerate schedule or save money; and identifying waste streams which currently have no path forward in the planning baseline. Consolidation/integration of planned activities may also provide opportunities for pollution prevention and/or avoidance of secondary waste generation. A workshop was held to review the waste disposition maps, and to identify opportunities with potential cost or schedule savings. Another workshop may be held to follow up on some …
Date: February 24, 1999
Creator: McDonald, K. M.
System: The UNT Digital Library
Coupled mechanical/heat transfer simulation on MPP platforms using a finite element/linear solver interface (open access)

Coupled mechanical/heat transfer simulation on MPP platforms using a finite element/linear solver interface

This report describes the implementation of a coupled mechanical /heat transfer simulation using a Finite Element Interface (FEI). The FE1 is an abstraction layer, which lies between the application code and its linear solver libraries, controlling the set-up and solution of the linear system arising in the finite element simulation. The performance and scalability of the ISIS++ FE1 is examined on the ASCI Red and Blue machines in the context of the ALE3D finite element simulation code.
Date: February 24, 1999
Creator: Aro, C J; Dube, E I & Futral, W S
System: The UNT Digital Library