Optimal Segmentation Strategy for Compact Representation of Hyperspectral Image Cubes (open access)

Optimal Segmentation Strategy for Compact Representation of Hyperspectral Image Cubes

By producing compact representations of hyperspectral image cubes (hypercubes), image storage requirements and the amount of time it takes to extract essential elements of information can both be dramatically reduced. However, these compact representations must preserve the important spectral features within hypercube pixels and the spatial structure associated with background and objects or phenomena of interest. This paper describes a novel approach for automatically and efficiently generating a particular type of compact hypercube representation, referred to as a supercube. The hypercube is segmented into regions that contain pixels with similar spectral shapes that are spatially connected, and the pixel connectivity constraint can be relaxed. Thresholds of similarity in spectral shape between pairs of pixels are derived directly from the hypercube data. One superpixel is generated for each region as some linear combination of pixels belonging to that region. The superpixels are optimal in the sense that the linear combination coefficients are computed so as to minimize the level of noise. Each hypercube pixel is represented in the supercube by applying a gain and bias to the superpixel assigned to the region containing that pixel. Examples are provided.
Date: February 8, 2000
Creator: Paglieroni, D & Roberts, R
System: The UNT Digital Library
Molecular dynamics simulation of cascade damage in gold (open access)

Molecular dynamics simulation of cascade damage in gold

High-energy cascades have been simulated in gold using molecular dynamics with a modified embedded atom method potential. The results show that both vacancy and interstitial clusters form with high probability as a result of intracascade processes. The formation of clusters has been interpreted in terms of the high pressures generated in the core of the cascade during the early stages. We provide evidence that correlation between interstitial and vacancy clustering exists.
Date: February 1, 2000
Creator: Alonso, E.; Caturla, M. J.; Tang, M.; Huang, H. & Diaz de la Rubia, T
System: The UNT Digital Library
Material transfer system in support of the plutonium immobilization program (open access)

Material transfer system in support of the plutonium immobilization program

The Plutonium Immobilization Project is currently undertaking formulation and process development to demonstrate the immobilization of surplus plutonium in a titanate-based ceramic. These ceramic forms will be encapsulated within canisters containing high level waste glass for geologic disposal. Process development work is being conducted with sub-scale, process prototypic equipment. Final validation of the process will be done using actual plutonium material and functionally prototypic equipment within a glovebox. Due to the radioactive nature of the material, remote material handling is necessary to reduce the radiation exposure to the operators. A remote operated Material Transfer System to interface with process equipment has been developed.
Date: February 23, 2000
Creator: Pak, D
System: The UNT Digital Library
Review of cathodic arc deposition technology at the start of the new millennium (open access)

Review of cathodic arc deposition technology at the start of the new millennium

The vacuum cathodic arc has been known to provide a means of producing coatings since the second half of the 19th century. This makes it one of the oldest known means for making coatings in a vacuum. In the last century it has been recognized that the copious quantities of ions produced by the process offers certain advantages in terms of coating properties. Specifically, ions can be steered and/or accelerated toward the parts to be coated. This, in turn, can provide enhanced adhesion, film density, and composition stoichiometry in the case of compound coatings. The ions generated by the cathodic arc have high ''natural'' kinetic energy values in the range 20-200 eV, leading to enhanced surface mobility during the deposition process and even ion subplantation. In many cases, dense coatings are achieved even when non-normal arrival angles are involved. The ion energy can further manipulated by the plasma immersion biasing technique. The issue of macroparticle contamination has been addressed by a variety of novel plasma filters. In spite of all of these advantages, this deposition technique has not been widely adopted in the western nations for commercial coating except in the case of enhancing the performance of cutting tools. The …
Date: February 24, 2000
Creator: Sanders, D. M. & Anders, A.
System: The UNT Digital Library
Experiences with BoomerAMG:: A Parallel Algebraic Multigrid Solver and Preconditioner for Large Linear Systems (open access)

Experiences with BoomerAMG:: A Parallel Algebraic Multigrid Solver and Preconditioner for Large Linear Systems

Algebraic multigrid (AMG) is an attractive choice for solving large linear systems {Lambda}x = b on unstructured grids. While AMG is applicable as a solver for a variety of problems, its robustness may be enhanced by using it as a preconditioner for Krylov solvers, such as GMRES. The sheer size of modern problems, hundreds of millions or billions of unknowns, dictates the use of massively parallel computers. AMG consists of two phases: the setup phase, in which smaller and smaller linear systems are generated by means of linear transfer operators (interpolation and restriction); and the solve phase, which employs a smoothing operator, such as Gauss-Seidel or Jacobi relaxation. Most of these components can be parallelized in a straightforward fashion; however, the coarse-grid selection, in which the grid for a smaller linear system is created on which the error can be approximated, is highly sequential. It is important to develop parallel coarsening techniques. They briefly present here the coarsening algorithms used in the parallel AMG code ''Boomer AMG'' and summarize some performance results for those algorithms. A detailed discussion of the algorithms and numerical results will be found.
Date: February 22, 2000
Creator: Hensor, V E & Yang, U M
System: The UNT Digital Library
The use of magnetron arrays for depositing large-area oxide coatings (open access)

The use of magnetron arrays for depositing large-area oxide coatings

The application of coatings over large areas can be approached through the use of large deposition sources. A versatile alternative, e.g. to long rectangular magnetrons, are linear arrays of circular planar magnetrons to process coatings over wide path lengths. They investigate the feasibility of using a linear array of 76 mm diameter magnetron sources operated in the rf mode to deposit oxide target materials across a path in excess of 0.7 m wide. Specific results are given for the case of a 2 {micro}m thick, alumina coating.
Date: February 23, 2000
Creator: Jankowski, Alan Frederic; McKernan, M. & Chesser, J.
System: The UNT Digital Library
Process development testing in support of the plutonium immobilization program (open access)

Process development testing in support of the plutonium immobilization program

As an integral part of the plutonium disposition program, formulation and process development is being performed for the immobilization of surplus plutonium in a titanate-based ceramic. Small-scale process prototypic and lab-scale functionally prototypic equipment have been tested to help define the immobilization process. The testing has included non-radioactive surrogates and actual actinide oxides contained in the immobilized form. A summary of the process development studies, as well as the formulation studies relevant to the process, will be provided.
Date: February 11, 2000
Creator: Herman, C. & Ebbinghaus, B.
System: The UNT Digital Library
After globalization future security in a technology rich world (open access)

After globalization future security in a technology rich world

Over the course of the year 2000, five one-day workshops were conducted by the Center for Global Security Research at the Lawrence Livermore National Laboratory on threats that might come against the US and its allies in the 2015 to 2020 timeframe due to the global availability of advanced technology. These workshops focused on threats that are enabled by nuclear, missile, and space technology; military technology; information technology; bio technology; and geo systems technology. In December, an Integration Workshop and Senior Review before national leaders and experts were held. The participants and reviewers were invited from the DOE National Laboratories, the DOD Services, OSD, DTRA, and DARPA, the DOS, NASA, Congressional technical staff, the intelligence community, universities and university study centers, think tanks, consultants on national security issues, and private industry. For each workshop the process of analysis involved identification and prioritization of the participants' perceived most severe threat scenarios (worst nightmares), discussion of the technologies which enabled those threats, and ranking of the technologies' threat potentials. We were not concerned in this exercise with defining responses, although our assessment of each threat's severity included consideration of the ease or difficulty with which it might be countered. At the concluding …
Date: February 12, 2000
Creator: Gilmartin, T J
System: The UNT Digital Library
Superlattice Effects on the Amorphization of Ni-Ti Multilayers (open access)

Superlattice Effects on the Amorphization of Ni-Ti Multilayers

A phenomenological model is proposed to correlate the onset of solid-state amorphization with the loss of interfacial stability in Ni-Ti multilayers. Additionally, a temperature dependence to the onset of amorphization is attributed to the effect of interfacial coherency that varies with the Ni-Ti layer pair spacing.
Date: February 10, 2000
Creator: Jankowski, Alan Frederic
System: The UNT Digital Library
Small Optical Components for the National Ignition Facility (open access)

Small Optical Components for the National Ignition Facility

The National Ignition Facility will be the largest laser system in the world. The facility, currently under construction, requires over 25,000 small optical components. The small-optics requirements and latest procurement strategy will be presented.
Date: February 15, 2000
Creator: Taylor, J R; Chow, R & Bissinger, H D
System: The UNT Digital Library
Polarized light propagation through tissue and tissue phantoms (open access)

Polarized light propagation through tissue and tissue phantoms

We show that standard tissue phantoms can be used to mimic the intensity and polarization properties of tissue. Polarized light propagation through biologic tissue is typically studied using tissue phantoms consisting of dilute aqueous suspensions of microspheres. The dilute phantoms can empirically match tissue polarization and intensity properties. One discrepancy between the dilute phantoms and tissue exist: common tissue phantoms, such as dilute Intralipid and dilute 1-{micro}m-diameter polystyrene microsphere suspensions, depolarize linearly polarized light more quickly than circularly polarized light. In dense tissue, however, where scatterers are often located in close proximity to one another, circularly polarized light is depolarized similar to or more quickly than linearly polarized light. We also demonstrate that polarized light propagates differently in dilute versus densely packed microsphere suspensions, which may account for the differences seen between polarized light propagation in common dilute tissue phantoms versus dense biologic tissue.
Date: February 8, 2000
Creator: Sankaran, V; Walsh, J T JR & Maitland, D J
System: The UNT Digital Library
Milling and blending of ceramic powders for the plutonium immobilization program (open access)

Milling and blending of ceramic powders for the plutonium immobilization program

The goal of the Plutonium Immobilization Program is the immobilization of surplus weapons usable plutonium in a ceramic form. The ceramic will then be encapsulated in high level waste glass using the can-in-can configuration. In the ceramic line of the immobilization plant, surplus plutonium oxide of less than 100 micron particle size will be received for immobilization. The plutonium oxide must be sized reduced and intimately blended with uranium oxide and the other ceramic forming materials containing neutron poisons to allow for complete interaction during sintering. Once properly blended, the formulation will be pressed into the desired ceramic form and then sintered to produce the targeted mineral phases. The equipment of choice for the size reduction of the actinides and the blending with the precursor materials is the Union Process attritor mill. The attritor mill is best described as a stirred ball mill and consists of a stationary tank filled with grinding media that is agitated by a shaft with stirring arms. The rotational shaft stirs the media at high-speed causing shearing and impact forces on the material resulting in size reduction and dispersion. Speeds over 1000 rpm can be reached by the stirring shaft. The high-speed of the attritor …
Date: February 14, 2000
Creator: Herman, D. T. & Biehl, W. E.
System: The UNT Digital Library
The matrix metalloproteinase stromelysin-1 acts as a natural mammary tumor promoter (open access)

The matrix metalloproteinase stromelysin-1 acts as a natural mammary tumor promoter

None
Date: February 21, 2000
Creator: Sternlicht, Mark D; Bissell, Mina J & Werb, Zena
System: The UNT Digital Library
MSW Effects in Vacuum Oscillations (open access)

MSW Effects in Vacuum Oscillations

We point out that for solar neutrino oscillations with the mass-squared difference of Delta m^2 ~;; 10^-10 - 10^-9 eV^2, traditionally known as"vacuum oscillation'' range, the solar matter effects are non-negligible, particularly for the low energy pp neutrinos. One consequence of this is that the values of the mixing angle theta and pi/2-theta are not equivalent, leading to the need to consider the entire physical range of the mixing angle 0<=theta<=pi/2 when determining the allowed values of the neutrino oscillation parameters.
Date: February 6, 2000
Creator: Friedland, Alexander
System: The UNT Digital Library
Quantum mechanical cluster calculations of critical scintillationprocesses (open access)

Quantum mechanical cluster calculations of critical scintillationprocesses

This paper describes the use of commercial quantum chemistrycodes to simu-late several critical scintillation processes. The crystalis modeled as a cluster of typically 50 atoms embedded in an array oftypically 5,000 point charges designed to reproduce the electrostaticfield of the infinite crystal. The Schrodinger equation is solved for theground, ionized, and excited states of the system to determine the energyand electron wavefunction. Computational methods for the followingcritical processes are described: (1) the formation and diffusion ofrelaxed holes, (2) the formation of excitons, (3) the trapping ofelectrons and holes by activator atoms, (4) the excitation of activatoratoms, and (5) thermal quenching. Examples include hole diffusion in CsI,the exciton in CsI, the excited state of CsI:Tl, the energy barrier forthe diffusion of relaxed holes in CaF2 and PbF2, and prompt hole trappingby activator atoms in CaF2:Eu and CdS:Te leading to an ultra-fast (<50ps) scintillation risetime.
Date: February 22, 2000
Creator: Derenzo, Stephen E.; Klintenberg, Mattias K. & Weber, Marvin J.
System: The UNT Digital Library
Femtosecond electron and x-ray generation by laser andplasma-based sources (open access)

Femtosecond electron and x-ray generation by laser andplasma-based sources

The generation of ultra-short x-rays by Thomson scattering intense laser pulses from electron beams is discussed, including recent experimental results and methods for enhancing the x-ray flux. A high flux of x-rays in a femtosecond pulse requires the generation of femtosecond electron bunches and a head-on Thomson scattering geometry. The generation of ultrashort electron bunches in a plasma-based accelerator with an injection technique that uses two colliding laser pulses is discussed. Simulations indicate the bunches as short as a few fs can be produced. Conversion of the fs electron pulse to a fs x-ray pulse can be accomplished by Bremsstrahlung or Thomson scattering.
Date: February 1, 2000
Creator: Esarey, E. & Leemans, W. P.
System: The UNT Digital Library
Innovative Confinement Concepts Workshop 2000 (Book ofAbstracts) (open access)

Innovative Confinement Concepts Workshop 2000 (Book ofAbstracts)

None
Date: February 22, 2000
Creator: Celata, Christine & Staff, Accelerator and Fusion Research
System: The UNT Digital Library
Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole Magnet (open access)

Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole Magnet

A 'proof-of-principle' Nb{sub 3}Sn superconducting dual-bore dipole magnet was built from racetrack coils, as a first step in a program to develop an economical, 15 Tesla, accelerator-quality magnet. The mechanical design and magnet fabrication procedures are discussed. No training was required to achieve temperature-dependent plateau currents, despite several thermal cycles that involved partial magnet disassembly and substantial pre-load variations. Subsequent magnets are expected to approach 15 Tesla with substantially improved conductor.
Date: February 6, 2000
Creator: Chow, K.; Dietderich, D. R.; Gourlay, S. A.; Gupta, R.; Harnden, W.; Lietzke, A. F. et al.
System: The UNT Digital Library
AZU-1: A Candidate Breast Tumor Suppressor and Biomarker for Tumor Progression (open access)

AZU-1: A Candidate Breast Tumor Suppressor and Biomarker for Tumor Progression

To identify genes misregulated in the final stages of breast carcinogenesis, we performed differential display to compare the gene expression patterns of the human tumorigenic mammary epithelial cells, HMT-3522-T4-2, with those of their immediate premalignant progenitors, HMT-3522-S2. We identified a novel gene, called anti-zuai-1 (AZU-1), that was abundantly expressed in non- and premalignant cells and tissues but was appreciably reduced in breast tumor cell types and in primary tumors. The AZU-1 gene encodes an acidic 571-amino-acid protein containing at least two structurally distinct domains with potential protein-binding functions: an N-terminal serine and proline-rich domain with a predicted immunoglobulin-like fold and a C-terminal coiled-coil domain. In HMT-3522 cells, the bulk of AZU-1 protein resided in a detergent-extractable cytoplasmic pool and was present at much lower levels in tumorigenic T4-2 cells than in their nonmalignant counterparts. Reversion of the tumorigenic phenotype of T4-2 cells, by means described previously, was accompanied by the up-regulation of AZU-1. In addition, reexpression of AZU-1 in T4-2 cells, using viral vectors, was sufficient to reduce their malignant phenotype substantially, both in culture and in vivo. These results indicate that AZU-1 is a candidate breast tumor suppressor that may exert its effects by promoting correct tissue morphogenesis.
Date: February 4, 2000
Creator: Chen, Huei-Mei; Schmeichel, Karen L; Mian, I. Saira; Lelie`vre, Sophie; Petersen, Ole W & Bissell, Mina J
System: The UNT Digital Library
The use of pressurized bladders for stress control of superconducting magnets (open access)

The use of pressurized bladders for stress control of superconducting magnets

None
Date: February 16, 2000
Creator: Caspi, S.; Gourlay, S.; Hafalia, R.; Lietzke, A.; O'Neill, J.; Taylor, C. et al.
System: The UNT Digital Library
Bioinformatics in the information age (open access)

Bioinformatics in the information age

There is a well-known story about the blind man examining the elephant: the part of the elephant examined determines his perception of the whole beast. Perhaps bioinformatics--the shotgun marriage between biology and mathematics, computer science, and engineering--is like an elephant that occupies a large chair in the scientific living room. Given the demand for and shortage of researchers with the computer skills to handle large volumes of biological data, where exactly does the bioinformatics elephant sit? There are probably many biologists who feel that a major product of this bioinformatics elephant is large piles of waste material. If you have tried to plow through Web sites and software packages in search of a specific tool for analyzing and collating large amounts of research data, you may well feel the same way. But there has been progress with major initiatives to develop more computing power, educate biologists about computers, increase funding, and set standards. For our purposes, bioinformatics is not simply a biologically inclined rehash of information theory (1) nor is it a hodgepodge of computer science techniques for building, updating, and accessing biological data. Rather bioinformatics incorporates both of these capabilities into a broad interdisciplinary science that involves both conceptual …
Date: February 1, 2000
Creator: Spengler, Sylvia J.
System: The UNT Digital Library
Dynamic and Thermodynamic Behavior of Carboneous and Hydrogen-Bonding Materials (open access)

Dynamic and Thermodynamic Behavior of Carboneous and Hydrogen-Bonding Materials

Dissociation behavior of carboneous materials with or without fluorine atoms at pressures (P) of tens of gigapascal (GPa) and temperature (T) at several thousand Kelvin is not so well understood. The main issues are: (a) carbon condensation processes and (b) thermodynamics of hydrogen fluoride (HF) produced from dissociation. Item (a) requires information on (i) the melting line of carbon, (ii) liquid carbon, (iii) stability and energy barrier between graphite and diamond clusters, and (iv) kinetics of cluster growth. Item (b) requires knowledge of (v) intermolecular potentials involving HF and (vi) influence of fluorine chemistry on supercritical phase change. The details concerning these issues are described.
Date: February 4, 2000
Creator: Ree, F. H.; Galli, G.; Glosli, J. N.; Gygi, F.; Schwegler, E.; Viecelli, J. A. et al.
System: The UNT Digital Library
Effective File I/O Bandwidth Benchmark (open access)

Effective File I/O Bandwidth Benchmark

The effective I/O bandwidth benchmark (b{_}eff{_}io) covers two goals: (1) to achieve a characteristic average number for the I/O bandwidth achievable with parallel MPI-I/O applications, and (2) to get detailed information about several access patterns and buffer lengths. The benchmark examines ''first write'', ''rewrite'' and ''read'' access, strided (individual and shared pointers) and segmented collective patterns on one file per application and non-collective access to one file per process. The number of parallel accessing processes is also varied and well-formed I/O is compared with non-well formed. On systems, meeting the rule that the total memory can be written to disk in 10 minutes, the benchmark should not need more than 15 minutes for a first pass of all patterns. The benchmark is designed analogously to the effective bandwidth benchmark for message passing (b{_}eff) that characterizes the message passing capabilities of a system in a few minutes. First results of the b{_}eff{_}io benchmark are given for IBM SP and Cray T3E systems and compared with existing benchmarks based on parallel Posix-I/O.
Date: February 15, 2000
Creator: Rabenseifner, R. & Koniges, A. E.
System: The UNT Digital Library
The Advantages of Fixed Facilities in Characterizing TRU Wastes (open access)

The Advantages of Fixed Facilities in Characterizing TRU Wastes

In May 1998 the Hanford Site started developing a program for characterization of transuranic (TRU) waste for shipment to the Waste Isolation Pilot Plant (WIPP) in New Mexico. After less than two years, Hanford will have a program certified by the Carlsbad Area Office (CAO). By picking a simple waste stream, taking advantage of lessons learned at the other sites, as well as communicating effectively with the CAO, Hanford was able to achieve certification in record time. This effort was further simplified by having a centralized program centered on the Waste Receiving and Processing (WRAP) Facility that contains most of the equipment required to characterize TRU waste. The use of fixed facilities for the characterization of TRU waste at sites with a long-term clean-up mission can be cost effective for several reasons. These include the ability to control the environment in which sensitive instrumentation is required to operate and ensuring that calibrations and maintenance activities are scheduled and performed as an operating routine. Other factors contributing to cost effectiveness include providing approved procedures and facilities for handling hazardous materials and anticipated contingencies and performing essential evolutions, and regulating and smoothing the work load and environmental conditions to provide maximal efficiency …
Date: February 8, 2000
Creator: FRENCH, M.S.
System: The UNT Digital Library