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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
Numerical modeling of a small recirculating induction accelerator for heavy-ion fusion (open access)

Numerical modeling of a small recirculating induction accelerator for heavy-ion fusion

A series of small-scale experiments has been proposed to study critical physics issues of a circular induction accelerator for heavy-ion fusion. Because the beam dynamics will be dominated by space charge, the experiments require careful design of the lattice and acceleration schedule. A hierarchy of codes has been developed for modeling the experiments at different levels of detail. The codes are discussed briefly, and examples of the output are presented.
Date: June 24, 1994
Creator: Sharp, W. M.; Barnard, J. J.; Friedman, A.; Grote, D. P.; Lund, S. M.; Newton, M. A. et al.
System: The UNT Digital Library
Magnetic hysteresis and flux creep of YBa{sub 2}Cu{sub 3}O{sub x} grown by the melt-powder-melt-growth (MPMG) process (open access)

Magnetic hysteresis and flux creep of YBa{sub 2}Cu{sub 3}O{sub x} grown by the melt-powder-melt-growth (MPMG) process

Magnetic hysteresis and flux creep of melt-powder-melt-growth (MPMG) YBa{sub 2}Cu{sub 3}O{sub x} containing nominal 0, 25 and 40 mole% Y{sub 2}BaCuO{sub 5} (21 1) were measured in the temperature range of 5 to 80 K and in magnetic fields up to 5 T. With the introduced fine dispersion of second phase 211 particles, the critical magnetization current density J{sub c} shows a weak field dependence over a wide range of temperature, and the effective pinning energy U{sub eff} is much enhanced. From these results, a functional expression U{sub eff}(J,T) = {minus} U{sub o} G(T) (J {vert_bar}J{sub i}){sup n} is obtained, where G(T) = [1 {minus} (T{vert_bar}T{sub x}){sup 2}]{sup 2} with Tx = 82.5 K near the irreversibility temperature. The observed power-law relationship of U{sub eff}(J, T) clearly demonstrates two of three regimes as predicted by the theory of collective flux creep, namely n = 3/2 and 7/9 for J < J{sub c} and J {much_lt} J{sub c}, respectively. In addition, the divergence of U{sub eff} at low current densities also suggests the existence of a vortex-glass state.
Date: August 24, 1992
Creator: Kung, P. J.; McHenry, M. E.; Maley, M. P.; Willis, J. O.; Murakami, M. & Tanaka, S.
System: The UNT Digital Library
Organizing for public involvement in Fernald decision-making (open access)

Organizing for public involvement in Fernald decision-making

Fernald is returning to the basics of interpersonal communication as a cornerstone of its public involvement program. The guiding premise behind this concept is the belief that face-to-face interaction between people is more likely to build trust and confidence than public meetings, news releases and other traditional public information techniques. A network of project spokespersons, called ``envoys,`` is being organized to develop person-to-person relationships with people interested in the future of Fernald. To support this approach, public affairs personnel are adopting roles as management consultants and communications coaches in addition to serving in their traditional role as public information specialists. Early observations seem to show signs of improvement in the level of public trust in Fernald decision-makers.
Date: October 24, 1993
Creator: Morgan, K. L. & Hoopes, J.
System: The UNT Digital Library
Low toxicity aromatic diamine curing agents for adhesives (open access)

Low toxicity aromatic diamine curing agents for adhesives

Increasing severity of regulations for handling of hazardous materials has led to formulation of adhesives with considerably lowered toxicities for use at the Oak Ridge Y-12 Plant. Fundamental was the development of Asilamine aromatic diamines, a family of liquid aromatic diamines useful as substitutes for methylenedianiline (MDA), a widely used adhesives curing agent. The use of Asilamine has allowed us to continue operations without dealing with expensive measures for regulation of MDA as a carcinogen promulgated by the Occupational Safety and Health Administration (OSHA).
Date: August 24, 1993
Creator: Dorsey, G. F.
System: The UNT Digital Library
Radio galaxies and their environment (open access)

Radio galaxies and their environment

The relationships between radio galaxies and their environment are varied, complex, and evolve with cosmic epoch. Basic questions are what role the environment plays in triggering and fuelling (radio) galaxy activity what the effects of this activity are on its environment, and how radio galaxies and environment evolve. Clearly, this could be the topic of a workshop all in itself and the scope of this review will necessarily be limited. A review of the connections between environment and galaxy activity in general has been given by Heckman. First, I will briefly summarize the relationships between parent galaxy and cluster environments, and radio galaxies. A more detailed discussion of various aspects of this will be given elsewhere by F. Owen, J.0. Burns and R. Perley. I will then discuss the current status of investigations of extended emission-line regions in radio galaxies, again referring elsewhere in this volume for more detailed discussions of some particular aspects (kinematics and ionization mechanisms by K. Meisenheimer; polarization and spectral index lobe asymmetries by G. Pooley). I will conclude with a brief discussion of the current status of observations of high redshift radio galaxies.
Date: February 24, 1993
Creator: van Breugel, W.
System: The UNT Digital Library
Primary charge separation in isolated photosystem II reaction centers (open access)

Primary charge separation in isolated photosystem II reaction centers

Primary charge-separation in isolated bacterial reaction center (RC) complex occurs in 2.8 ps at room temperature and 0.7--1.2 ps at 10 K. Because of similarities between the bacterial and photosystem II (PSII) RCs, it has been of considerable interest to obtain analogous charge-separation rates in the higher plant system. Our previous femtosecond transient absorption studies used PSII RC material stabilized with PEG or by exchanging dodecyl maltoside (DM) for Triton in the isolation procedure. These materials gave charge-separation 1/e times of 3.0 {plus_minus} 0.6 ps at 4{degree}C and 1.4{plus_minus} 0.2 ps at 15 K based on the risetime of transient absorption kinetics at 820 nm. These values were thought to represent the time required for formation of the P680{sup +}-Pheo{sup {minus}} state. Recent results of Hastings et al. obtained at high data acquisition rates and low flash intensities, suggest that the Pheo{sup {minus}} state may form more slowly. In light of this work, we have carried out additional time domain studies of both electron transport and energy transfer phenomena in stabilized DM PSII RCs at room temperature. We used a 1-kHz repetition rate femtosecond transient absorption spectrometer with a 200 fs instrumental time resolution and compared the results with those …
Date: August 24, 1992
Creator: Seibert, M.; Toon, S.; Govindjee; O`Neil, M. P. & Wasielewski, M. R.
System: The UNT Digital Library
Local critical current measurements on (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} tape with an electromagnetic probe (open access)

Local critical current measurements on (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} tape with an electromagnetic probe

The ability to measure critical currents in high {Tc} superconducting tapes on a local scale is valuable for optimizing the fabrication process. This paper describes the use of induced currents from a small noncontacting electromagnetic probe to determine the critical current density in a (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}/Ag tape on a local scale. The technique forces full field penetration into the tape locally and infers the critical current density from the Bean critical state model, accounting for the Ag overlayers. Critical current images of the till can be obtained by scanning the probe over the tape surface with spatial resolution on the order of 1.0 mm. Results for tapes with different microstructures we discussed.
Date: August 24, 1992
Creator: Telschow, K. L.; O`Brien, T. K.; Lanagan, M. T. & Kaufman, D. Y.
System: The UNT Digital Library
The other high resolution post accelerator approach (open access)

The other high resolution post accelerator approach

There has been significant discussion in consideration of a high resolution mass separator followed by a RFQ and a linear accelerator as the basic format for IsoSpin Laboratory. There exists another strong possibility-namely a low-resolution mass separator coupled to a cyclotron. The major objection to this approach has been that the conversion from the +1 mass separator beam to a q/m beam of 1/4 to 1/3 is thought to be highly inefficient. Since we are in the fortunate position of having the two expensive components of this system available for tests (an on-line mass separator and an ECR source), we intend to couple these devices to actually measure these efficiencies and to test ideas for improving the efficiency. We present some specifics of this approach.
Date: May 24, 1993
Creator: Moltz, D. M.; Tighe, R. J.; Rowe, M. W.; Ognibene, T. J. & Cerny, J.
System: The UNT Digital Library
Single sided tomography of extremely large dense objects (open access)

Single sided tomography of extremely large dense objects

One can envision many circumstances where radiography could be valuable but is frustrated by the geometry of the object to be radiographed. For example, extremely large objects, the separation of rocket propellants from the skin of solid fuel rocket motor, the structural integrity of an underground tank or hull of a ship, the location of buried objects, inspection of large castings etc. The author has been investigating ways to do this type of radiography and as a result has developed a technique which can be used to obtain three dimensional radiographs using Compton scattered radiation from a monochromatic source and a high efficiency, high resolution germanium spectrometer. This paper gives specific details of the reconstruction technique and presents the results of numerous numerical simulations and compares these simulations to spectra obtained in the laboratory. In addition the author presents the results of calculations made for the development of an alternative single sided radiography technique which will permit inspection of the interior of large objects. As a benchmark the author seeks to obtain three dimensional images with a resolution of about one cubic centimeter in a concrete cube 30 centimeters on a side. Such a device must use photons of very …
Date: March 24, 1993
Creator: Thoe, R. S.
System: The UNT Digital Library
Interstitial embrittlement in vanadium laser welds (open access)

Interstitial embrittlement in vanadium laser welds

Efficiencies of interstitial absorption during pulsed ND:YAG laser welding of vanadium were compared for nitrogen, oxygen, hydrogen, and water vapor. Influence of interstitial levels on the embrittlement of vanadium laser welds was also measured. For 1000 ppM contaminant levels in the weld atmosphere, weld hydrogen content increased 9 ppM, nitrogen content increased 190 ppM, and oxygen content increased from 500 ppM relative to baseplate levels. Welds in ultrahigh-purity argon atmospheres contained 3 ppM hydrogen, 40 ppM nitrogen, and 250 ppM oxygen. Longitudinal all-weld tensile specimens and notched-plate specimens were used to measure weld metal tensile properties at {minus}55C. All of the laser weld notch-strength ratios exceeded unity and weld metal tensile strengths all exceeded the baseplate values. For 1000 ppM atmosphere contaminant levels, the only significant decrease in ductility, as measured by reduction-in-area at fracture was for the weld atmosphere containing oxygen. Weld atmospheres containing 1% nitrogen also reduced the weld ductility, and resulted in the onset of cleavage fracture.
Date: February 24, 1992
Creator: Strum, M. J. & Wagner, L. M.
System: The UNT Digital Library
High resolution tomography of objects with access to a single side (open access)

High resolution tomography of objects with access to a single side

The author is developing a technique which will enable one to obtain high-contrast, high-spatial resolution, three-dimensional images in opaque objects. The only constraint will be the radiation source and detector(s) will be located on the same side of the object. The goal is to obtain images with a spatial resolution of {approximately}1 mm at depths of 10 mm and {approximately}3 mm at depths of 30 mm in materials of moderate density (brass, steel, etc.). The author`s technique uses a highly-collimated beam of monochromatic gamma rays and a slit collimated high-resolution, high-efficiency, coaxial germanium spectrometer. If the geometry is well known, the spectrum of Compton scattered radiation can be used to map out the density as a function of depth. By scanning the object in two dimensions, a full three-dimensional image of the electron density can be reconstructed. The resolution is dependent on the incident beam collimation and the energy resolution of the spectrometer. For his system, the author anticipates a resolution of about 1 mm{sup 3}. The apparatus, reconstruction algorithms and current data verifying his predictions are presented here. Also included are the details on how the system can be modified to increase the efficiency by over two orders of …
Date: March 24, 1993
Creator: Thoe, R. S.
System: The UNT Digital Library
Visualization of high resolution, three-dimensional, nonlinear finite element analyses (open access)

Visualization of high resolution, three-dimensional, nonlinear finite element analyses

A two-pass surface extraction algorithm for adaptive finite element meshes is presented in the context of a visualization study for a particle impact and a turbine containment problem. The direct use of finite element data structures for the computation of external surfaces, surface normals, and derived physical quantities is discussed. An overview of the in-betweening algorithm which compensates for rigid body dynamics is presented with a brief discussion of a {open_quotes}direct-to-videodisk{close_quotes} animation strategy.
Date: March 24, 1992
Creator: Christon, M. A. & Spelce, T. E.
System: The UNT Digital Library
Evaluation of LLNL-ALICE code contribution (open access)

Evaluation of LLNL-ALICE code contribution

We summarize some of the areas of comparison with experimental data for which the ALICE code did poorly. We suggest some aspects which might be improved in the future. A crude accuracy factor is estimated as a predictive reliability based on the intercomparison exercise.
Date: March 24, 1994
Creator: Blann, M.
System: The UNT Digital Library
Kinetic effects near the magnetopause (open access)

Kinetic effects near the magnetopause

Boundary conditions for magnetopause processes such as reconnection can be understood by studying the properties of magnetosheath plasma as it flows toward this transition. This manuscript reviews the role of electromagnetic ion cyclotron instabilities in constraining ion temperature anisotropies in the magnetosheath. Linear Vlasov theory and hybrid computer simulations have demonstrated that the inverse correlation between the proton anisotropy and the parallel proton {beta} observed from AMPTE/CCE in the subsolar sheath is due to wave-particle scattering by ion cyclotron anisotropy instabilities. Recent research on this topic is reviewed and the application of this inverse correlation to a successful bounded anisotropy model of proton temperatures in the sheath is described.
Date: March 24, 1994
Creator: Gary, S. P.; Winske, D.; McKean, M. E.; Fuselier, S. A.; Denton, R. E. & Anderson, B. J.
System: The UNT Digital Library
Model-based ocean acoustic passive localization (open access)

Model-based ocean acoustic passive localization

The detection, localization and classification of acoustic sources (targets) in a hostile ocean environment is a difficult problem -- especially in light of the improved design of modern submarines and the continual improvement in quieting technology. Further the advent of more and more diesel-powered vessels makes the detection problem even more formidable than ever before. It has recently been recognized that the incorporation of a mathematical model that accurately represents the phenomenology under investigation can vastly improve the performance of any processor, assuming, of course, that the model is accurate. Therefore, it is necessary to incorporate more knowledge about the ocean environment into detection and localization algorithms in order to enhance the overall signal-to-noise ratios and improve performance. An alternative methodology to matched-field/matched-mode processing is the so-called model-based processor which is based on a state-space representation of the normal-mode propagation model. If state-space solutions can be accomplished, then many of the current ocean acoustic processing problems can be analyzed and solved using this framework to analyze performance results based on firm statistical and system theoretic grounds. The model-based approach, is (simply) ``incorporating mathematical models of both physical phenomenology and the measurement processes including noise into the processor to extract the …
Date: January 24, 1994
Creator: Candy, J. V. & Sullivan, E. J.
System: The UNT Digital Library
Relationships of radon diffusion coefficient with saturated hydraulic conductivity, fines content and moisture saturation of radon/infiltration barriers for the UMTRA Project (open access)

Relationships of radon diffusion coefficient with saturated hydraulic conductivity, fines content and moisture saturation of radon/infiltration barriers for the UMTRA Project

The release of {sup 222}Radon to the atmosphere is controlled by the rate of its gas transport through earthen materials. Of the many soil-related parameters, radon diffusion coefficient is the key parameter that characterizes this transport. We compared the radon diffusion coefficients measured at the laboratories for the UMTRA Project with simple empirical correlations developed by others. The empirical correlations predict the radon diffusion coefficient based on the fraction of moisture saturation and porosity. One of the more recent correlations agrees reasonably well with the measurements. In addition, by using a series of correlation curves, we studied the empirical relationships of the. radon diffusion coefficient with the saturated hydraulic conductivity, the fines content, and the moisture saturation in soil. The results reveal that a reliable determination of the long-term moisture and porosity is essential in the design of an adequate radon barrier with respect to the radon diffusion coefficient.
Date: January 24, 1994
Creator: Li, P. Y. & Chen, P. K.
System: The UNT Digital Library
Intercomparison of codes for intermediate energy nuclear data: The first step (open access)

Intercomparison of codes for intermediate energy nuclear data: The first step

Several weak points of the intermediate energy nuclear data calculated in this exercise are described as introduction to some of the areas needing discussion at this meeting. These include nuclear structure effects on precompound spectra, large variations between codes in predicted total reaction cross sections, and in total neutron and proton multiplicities. INC codes don`t reflect correct experimental Q values, and may have difficulties at very low angles due to overestimation of the quasi-elastic peak. We raise questions as to additional reaction properties (beyond n and p spectra) which may need benchmarking.
Date: March 24, 1994
Creator: Blann, M.; Gruppelaar, H.; Nagel, P. & Rodens, J.
System: The UNT Digital Library
A 10 GHz BANDWIDTH, SINGLE TRANSIENT, DIGITIZED OSCILLOSCOPE WITH 20 GHz CAPABILITY (open access)

A 10 GHz BANDWIDTH, SINGLE TRANSIENT, DIGITIZED OSCILLOSCOPE WITH 20 GHz CAPABILITY

EG&G/EM has developed an oscilloscope with a {minus}3 dB bandwidth greater than 10 GHz. Its rolloff characteristics are such that single-transient data greater than 20 GHz may be captured. A demountable CCD camera records the oscilloscope trace and is provided with PC-compatible capture and data processing software. The capabilities of the oscilloscope, camera, and its processing software are described and examples of the system`s performance is shown.
Date: January 24, 1994
Creator: Hudson, C. L.; Kocimski, S. M.; Spector, J.; Thomas, J. B. & Woodstra, R. R.
System: The UNT Digital Library
Decay properties of nuclei at the end of the periodic system (open access)

Decay properties of nuclei at the end of the periodic system

Recent studies of nuclear mass models show that it is essential to account for the Coulomb redistribution energy when calculating the nuclear potential energy in the heavy-element region. Results obtained by use of a mass model that includes Coulomb redistribution effects on analyzed. Q values of {alpha} and {beta} decay are calculated. Half-lives for {alpha} decay are estimated by use of the Viola-Seaborg systematics. For EC, {beta}{sup +} decay and {beta}{sup {minus}} decay, half-lives are calculated in a microscopic QRPA model. Calculated single-particle level structures in the heavy-element regions are presented. These indicate possible regions of isomers that would be unusually stable with respect to spontaneous fission and {alpha} decay. Finally, we discuss the implications of earlier extensive work on fission properties of nuclei in this region.
Date: January 24, 1992
Creator: Moeller, P. & Nix, J. R.
System: The UNT Digital Library
Rail transportation of Fernald remediation waste (open access)

Rail transportation of Fernald remediation waste

Remediation of the Department of Energy (DOE) Fernald site located north of Cincinnati will generate large quantities of low-level radwaste. This volume includes approximately 1,050,000 tons of material to be removed from eight waste pits comprising Operable Unit 1 (OU-1). The remedial alternative selected includes waste material excavation, drying and transportation by rail to a burial site in the arid west for disposal. Rail transportation was selected not only because rail transportation is safer than truck transportation, but also because of the sheer magnitude of the project and the availability of bulk rail car unloading facilities at a representative disposal site. Based upon current waste quantity estimates as presented in the Feasibility Study for OUI, a fully-loaded 47-car unit train would depart the Fernald site weekly for five years. This paper illustrates the steps taken to obtain agency and public acceptance of the Record of Decision for the remedy which hinged on rail transportation. A preliminary, but detailed, rail transportation plan was prepared for the project to support a series of CERCLA public meetings conducted in late 1994. Some of the major issues addressed in the plan included the following: (1) Scope of project leading to selection of rail transportation; …
Date: January 24, 1995
Creator: Fellman, R. T.; Lojek, D. A.; Motl, G. P. & Weddendorf, W. K.
System: The UNT Digital Library
Realization of vector fields for quantum groups as pseudodifferential operators on quantum spaces (open access)

Realization of vector fields for quantum groups as pseudodifferential operators on quantum spaces

The vector fields of the quantum Lie algebra are described for the quantum groups GL{sub q}(n), SL{sub q}(N) and SO{sub q}(N) as pseudodifferential operators on the linear quantum spaces covariant under the corresponding quantum group. Their expressions are simple and compact. It is pointed out that these vector fields satisfy certain characteristic polynomial identities. The real forms SU{sub q}(N) and SO{sub q}(N,R) are discussed in detail.
Date: January 24, 1995
Creator: Chu, Chong-Sun & Zumino, B.
System: The UNT Digital Library
Beam test of a large area silicon drift detector (open access)

Beam test of a large area silicon drift detector

The results from the tests of the first large area (4 {times} 4 cm{sup 2}) planar silicon drift detector prototype in a pion beam are reported. The measured position resolution in the drift direction is ({sigma}=40 {plus_minus} 10){mu}m.
Date: March 24, 1992
Creator: Castoldi, A.; Chinnici, S.; Gatti, E.; Longoni, A.; Palma, F.; Sampietro, M. et al.
System: The UNT Digital Library
Pollution prevention opportunity assessment: Foundation of pollution prevention for waste management (open access)

Pollution prevention opportunity assessment: Foundation of pollution prevention for waste management

The objective of this paper is to promote the Pollution Prevention Opportunity Assessment (PPOA) technique as a fundamental of pollution prevention for waste management. All key elements of an effective PPOA program are presented. These key elements include impacts of environmental laws on pollution prevention, PPOA concepts and overview, waste minimization opportunities assessment, reporting and monitoring waste minimization progress, and PPOA program implementation. As environmental laws evolve the focus is shifting from end-of-pipe pollution control to front-end source reduction. Waste minimization was mistakenly interpreted to mean the reduction of hazardous waste after generation in the past. The Pollution Prevention Act of 1990 has clearly defined its requirement on resource reduction. Waste reduction can be viewed as a criterion to assess all industrial processes and operations. The fundamental approach of PPOA focuses on a mass balance concept. This concept deals with tracking of chemicals from the point of purchase, through storage, utilization in the process, and waste generation at the end of process. In other words, PPOA is a technique to analyze this input/output process. By applying PPOA techniques, the framework of applicable compliance requirements to the current operation process is established. Furthermore, documentation of PPOA itself can meet as documentation …
Date: March 24, 1994
Creator: Damewood, R. W.
System: The UNT Digital Library