''Atomic Optics'': Nonimaging Optics on the Nanoscale (open access)

''Atomic Optics'': Nonimaging Optics on the Nanoscale

This is the final report for a one year close out extension of our basic research program that was established at the University of Chicago more than sixteen years ago to explore and develop the optical sub-discipline that has come to be known as ''nonimaging optics''. This program has been extremely fruitful, having both broadened the range of formalism available for workers in this field and led to the discovery of many new families of optical devices. These devices and techniques have applications wherever the efficient transport and transformation of light distributions are important, in particular in illumination, fiber optics, collection and concentration of sunlight, and the detection of faint light signals in physics and astrophysics. Over the past thirty years, Nonimaging Optics (Welford and Winston, 1989) has brought a fresh approach to the analysis of many problems in classical macro-scale optics. Through the application of phase-space concepts, statistical methods, thermodynamic arguments, etc., many previously established performance limits were able to be broken and many technical surprises with exciting practical applications were discovered. The most recent three-year phase of our long-term continuing program ended in late 2002 and emphasized extending our work in geometrical optics and expanding it to include …
Date: January 15, 2005
Creator: O'Gallagher, Roland Winston Joseph
Object Type: Report
System: The UNT Digital Library
CH-TRU Waste Content Codes (CH-TRUCON) (open access)

CH-TRU Waste Content Codes (CH-TRUCON)

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container. Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 …
Date: January 15, 2005
Creator: Westinghouse TRU Solutions LLC
Object Type: Report
System: The UNT Digital Library
Cyclotron Resonance and Quasiparticles (open access)

Cyclotron Resonance and Quasiparticles

This introductory paper contains personal perspectives about the importance of cyclotron resonance in forming our modern view of solids. The papers following this one will discuss the discovery, refinements, and some of the latest developments. Although I will touch on some of these subjects, I leave the details to the other authors and in the main focus on the conceptual impact of the work. I propose that it was experiments based on cyclotron resonance which established the quasiparticle concept.
Date: January 15, 2005
Creator: Cohen, Marvin L.
Object Type: Article
System: The UNT Digital Library
Evaluation of Roof Bolting Requirements Based on In-Mine Bolter Drilling Progress Report (open access)

Evaluation of Roof Bolting Requirements Based on In-Mine Bolter Drilling Progress Report

In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The main accomplishments in this quarter included: (1) one more field test has been conducted in an underground coal mine, (2) optimization studies of the control parameters have been conducted, (3) method to use torque to thrust ratio as indicator of rock relative hardness has also been explored, and (4) about 98% of the development work for the roof geology mapping program, MRGIS, has completed, (5) A real time roof geology mapping system for roof bolters in limestone mine, including a special version of the geology mapping program and hardware, has already been verified to perform very well in underground production condition.
Date: January 15, 2005
Creator: Peng, Syd S.
Object Type: Report
System: The UNT Digital Library
Further results about field theory on the world sheet and stringformation (open access)

Further results about field theory on the world sheet and stringformation

The present article is the continuation of the earlier work, which used the world sheet representation and the mean field approximation to sum planar graphs in massless {phi}{sup 3} field theory. The authors improve on the previous work in two respects: A prefactor in the world sheet propagator that had been neglected is now taken into account. In addition, they introduce a non-zero bare mass for the field {phi}. Working with a theory with cutoff and using the mean field approximation, they find that, depending on the range of values of the mass and coupling constant, the model has two phases: A string forming phase and a perturbative field theory phase. They also find the generation of a new degree of freedom, which was not in the model originally. This new degree of freedom can be thought of as the string slope, which is now promoted into a fluctuating dynamical variable. Finally, they show that the introduction of the bare mass makes it possible to renormalize the model.
Date: January 15, 2005
Creator: Bardakci, Korbut
Object Type: Article
System: The UNT Digital Library
Halliburton Composite Bridge Plug Assembly (open access)

Halliburton Composite Bridge Plug Assembly

The overall objectives of this CRADA were to assist Halliburton in analyzing a composite bridge plug and to determine why their original design was failing in the field. In Phase 1, finite element analyses were done on the original composite slip design and several alternative designs. The composite slip was the component in the bridge plug that was failing. The finite element code ABAQUS was used for these calculations and I-DEAS was used as the pre- and post-processor in the analyses. Several different designs and materials were analyzed and recommendations were made towards improving the design. In Phase 2, the objective was to develop finite element models that would accurately represent the deformations in the entire all-composite 4-1/2' diameter bridge plug assembly. The finite element code LS-DYNA was used and the results from this effort were intended to expand Halliburton's composite design and analysis capabilities with regard to developing future composite components for downhole tools. In addition to the finite element modeling, this effort involved the utilization of micromechanics to determine the necessary composite material properties that were needed as input for finite element codes.
Date: January 15, 2005
Creator: Starbuck, J. M.; Luttrell, C. R. & Aramayo, G.
Object Type: Report
System: The UNT Digital Library
Hydrogen and Nitrogen Control in Ladle and Casting Operations (open access)

Hydrogen and Nitrogen Control in Ladle and Casting Operations

In recent years there has been an increasing demand to reduce and control the amount of dissolved gases in steel. Hydrogen and nitrogen are two of the most important gases which when dissolved in liquid steel affect its properties significantly. Several steelmaking additions have been investigated in this research for their effect on the hydrogen and nitrogen content of steels. It has been established that calcium hydroxide (hydrated lime) acts as a source of hydrogen. Carburizers, such as metallurgical coke, were found to result in no hydrogen pickup when added to liquid steel. Addition of petroleum coke, on the other hand, increased the hydrogen content of liquid steel. Ferroalloy such as medium carbon ferromanganese when added to the liquid iron was found to increase its nitrogen content, the increase being proportional to the amount of ferroalloy added. Similarly, addition of pitch coke, which had a significant nitrogen impurity, increased the nitrogen content of liquid iron. A mathematical model was developed to quantify the absorption of nitrogen and hydrogen from the air bubbles entrained during tapping of liquid steel. During the bottom stirring of liquid metal in a ladle, the inert gas escaping from the top displaces the slag layer and …
Date: January 15, 2005
Creator: Fruehan, Richard J. & Misra, Siddhartha
Object Type: Report
System: The UNT Digital Library
Neutron Capture Experiments on Unstable Nuclei (open access)

Neutron Capture Experiments on Unstable Nuclei

The overall objective of this project is the measurement of neutron capture cross sections of importance to stewardship science and astrophysical modeling of nucleosynthesis, while at the same time helping to train the next generation of scientists with expertise relevant to U.S. national nuclear security missions and to stewardship science. A primary objective of this project is to study neutron capture cross sections for various stable and unstable isotopes that will contribute to the Science Based Stockpile Stewardship (SBSS) program by providing improved data for modeling and interpretation of nuclear device performance. Much of the information obtained will also be important in astrophysical modeling of nucleosynthesis. Measurements of these neutron capture cross sections are being conducted in collaboration with researchers at the Los Alamos Neutron Science Center (LANSCE) facility using the unique Detector for Advanced Neutron Capture Experiments (DANCE). In our early discussions with the DANCE group, decisions were made on the first cross sections to be measured and how our expertise in target preparation, radiochemical separations chemistry, and data analysis could best be applied. The initial emphasis of the project was on preparing suitable targets of both natural and separated stable europium isotopes in preparation for the ultimate goal …
Date: January 15, 2005
Creator: Schwantes, Jon M.; Sudowe, Ralf; Folden, Charles M., III; Nitsche, Heino & Hoffman, Darleane C.
Object Type: Report
System: The UNT Digital Library
Atomic-Resolution 3D Electron Microscopy with Dynamic Diffraction (open access)

Atomic-Resolution 3D Electron Microscopy with Dynamic Diffraction

Achievement of atomic-resolution electron-beam tomography will allow determination of the three-dimensional structure of nanoparticles (and other suitable specimens) at atomic resolution. Three-dimensional reconstructions will yield ''section'' images that resolve atoms overlapped in normal electron microscope images (projections), resolving lighter atoms such as oxygen in the presence of heavier atoms, and atoms that lie on non-lattice sites such as those in non-periodic defect structures. Lower-resolution electron microscope tomography has been used to produce reconstructed 3D images of nanoparticles [1] but extension to atomic resolution is considered not to be straightforward. Accurate three-dimensional reconstruction from two-dimensional projections generally requires that intensity in the series of 2-D images be a monotonic function of the specimen structure (often specimen density, but in our case atomic potential). This condition is not satisfied in electron microscopy when specimens with strong periodicity are tilted close to zone-axis orientation and produce ''anomalous'' image contrast because of strong dynamic diffraction components. Atomic-resolution reconstructions from tilt series containing zone-axis images (with their contrast enhanced by strong dynamical scattering) can be distorted when the stronger zone-axis images overwhelm images obtained in other ''random'' orientations in which atoms do not line up in neat columns. The first demonstrations of 3-D reconstruction to …
Date: February 15, 2005
Creator: O'Keefe, Michael A.; Downing, Kenneth H.; Wenk, Hans-Rudolf & Meisheng, Hu
Object Type: Article
System: The UNT Digital Library
Ceramic Laser Materials (open access)

Ceramic Laser Materials

Transparent ceramic materials have several major advantages over single crystals in laser applications, not the least of which is the ability to make large aperture parts in a robust manufacturing process. After more than a decade of working on making transparent YAG:Nd, Japanese workers have recently succeeded in demonstrating samples that performed as laser gain media as well as their single crystal counterparts. Since then several laser materials have been made and evaluated. For these reasons, developing ceramic laser materials is the most exciting and futuristic materials topic in today's major solid-state laser conferences. We have established a good working relationship with Konoshima Ltd., the Japanese producer of the best ceramic laser materials, and have procured and evaluated slabs designed by us for use in our high-powered SSHCL. Our measurements indicate that these materials will work in the SSHCL, and we have nearly completed retrofitting the SSHCL with four of the largest transparent ceramic YAG:Nd slabs in existence. We have also begun our own effort to make this material and have produced samples with various degrees of transparency/translucency. We are in the process of carrying out an extensive design-of-experiments to establish the significant process variables for making transparent YAG. Finally …
Date: February 15, 2005
Creator: Soules, T F; Clapsaddle, B J; Landingham, R L & Schaffers, K I
Object Type: Report
System: The UNT Digital Library
Comments on 'Pore-Scale Visulization of Colloid Transport andRetention in Partly Saturated Porous Media' (open access)

Comments on 'Pore-Scale Visulization of Colloid Transport andRetention in Partly Saturated Porous Media'

The recent study by Crist et al. (2004) attempted to provide pore scale insights into mechanisms responsible for controlling colloid transport in unsaturated porous media. However, because they relied on images obtained along surfaces that were open to the atmosphere, artificial evaporation resulted in 2 more critical artifacts; formation of air-water-solid (AWS) contact lines, and advection/deposition of colloids to AWS contact lines. These evaporation-related artifacts need to be addressed because they account for most of the colloid deposition at AWS contact lines reported in Crist et al. (2004)...As stated in Crist el al. (2004), ''... the front panel was removed to avoid light reflections that obscured the view and, thus, exposed one side of the sand column to air''. Although a more recent paper (Crist et al., 2005) also presents results using the same methods and is therefore also affected by evaporation, we will restrict our present comments to Crist et al. (2004). Here, we show that removal of the front panel results in a sequence of three critical artifacts; (1) significant evaporation, (2) drying of thin films and formation of air-water-solid (AWS) contact lines, and (3) advection of colloids to AWS contact lines where they are deposited. As explained …
Date: February 15, 2005
Creator: Wan, Jiamin & Tokunaga, Tetsu K.
Object Type: Article
System: The UNT Digital Library
The crystal structure of Rv1347c, a putative antibiotic resistance protein from Mycobacterium tuberculosis, reveals a GCN5-related fold and suggests an alternative function in siderophore biosynthesis (open access)

The crystal structure of Rv1347c, a putative antibiotic resistance protein from Mycobacterium tuberculosis, reveals a GCN5-related fold and suggests an alternative function in siderophore biosynthesis

Mycobacterium tuberculosis, the cause of TB, is a devastating human pathogen. The emergence of multi-drug resistance in recent years has prompted a search for new drug targets and for a better understanding of mechanisms of resistance. Here we focus on the gene product of an open reading frame from M. tuberculosis, Rv1347c, which is annotated as a putative aminoglycoside N-acetyltransferase. The Rv1347c protein does not show this activity, however, and we show from its crystal structure, coupled with functional and bioinformatic data, that its most likely role is in the biosynthesis of mycobactin, the M. tuberculosis siderophore. The crystal structure of Rv1347c was determined by MAD phasing from selenomethionine-substituted protein and refined at 2.2 {angstrom} resolution (R = 0.227, R{sub free} = 0.257). The protein is monomeric, with a fold that places it in the GCN5-related N-acetyltransferase (GNAT) family of acyltransferases. Features of the structure are an acylCoA binding site that is shared with other GNAT family members, and an adjacent hydrophobic channel leading to the surface that could accommodate long-chain acyl groups. Modeling the postulated substrate, the N{sup {var_epsilon}}-hydroxylysine side chain of mycobactin, into the acceptor substrate binding groove identifies two residues at the active site, His130 and Asp168, …
Date: February 15, 2005
Creator: Card, G. L.; Peterson, N. A.; Smith, C. A.; Rupp, B.; Schick, B. M. & Baker, E. N.
Object Type: Article
System: The UNT Digital Library
Density Measurements of Be Shells (open access)

Density Measurements of Be Shells

The purpose of this memo is to lay out the uncertainties associated with the measurement of density of Be ablators by the weigh and volume method. I am counting on the readers to point out any faulty assumptions about the techniques or uncertainties associated with them. Based on the analysis presented below we should expect that 30 {micro}m thick shells will have an uncertainty in the measured density of about 2% of the value, coming more or less equally from the mass and volume measurement. The uncertainty is roughly inversely proportional to the coating thickness, thus a 60 {micro}m walled shell would result in a 1% uncertainty in the density.
Date: February 15, 2005
Creator: Cook, R C
Object Type: Report
System: The UNT Digital Library
Design and Performance Characteristics of the ORNL AdvancedMicroscopy Laboratory and JEOL 2200FS-AC Aberration-CorrectedSTEM/TEM (open access)

Design and Performance Characteristics of the ORNL AdvancedMicroscopy Laboratory and JEOL 2200FS-AC Aberration-CorrectedSTEM/TEM

At ORNL, the new Advanced Microscopy Laboratory (AML) has recently been completed, with two aberration-corrected instruments installed, and two more planned in the near future to fill the 4-laboratory building. The installed JEOL 2200FS-AC has demonstrated aTEM information limit of 0.9A. This limit is expected given the measured instrument parameters (HT and OL power supply stabilities, beam energy spread, etc.), and illustrates that the environmental influences are not adversely affecting the instrument performance. In STEM high-angle annular dark-field (HA-ADF) mode, images of a thin Si crystal in<110>zone axis orientation, after primary aberrations in the illuminating beam were optimally corrected, showed a significant vibration effect. The microscope is fitted with three magnetically levitated turbo pumps (one on the column at about the specimen position,and two near floor level) that pump the Omega energy filter and detector chamber. These pumps run at 48,000 rpm, precisely equivalent to 800Hz. It was determined that the upper turbo pump was contributing essentially all of the 800Hz signal to the image, and in fact that the pump was defective. After replacing the pump with one significantly quieter than the original, the Si atomic column image and associated diffractogram(Fig. 4b) show a much-reduced effect of the 800Hz …
Date: February 15, 2005
Creator: Allard, Lawrence F.; Blom, Douglas A.; O'Keefe, Michael A. & Mishina, S.
Object Type: Article
System: The UNT Digital Library
Detection and Quantification of Pu(III, IV, V, and VI) Using a1.0-meter Liquid Core Waveguide (open access)

Detection and Quantification of Pu(III, IV, V, and VI) Using a1.0-meter Liquid Core Waveguide

Detection and quantification of the aquo ions of Pu in 1 MHClO4 was carried out using a 1-meter liquid core waveguide (LCW) coupledto a fiber optic UV-Vis spectrometer. Detection limits of 7 x 10-7 M forPu(VI), 1.6 x 10-5 M for Pu(V), 5 x 10-6 M for Pu(IV) and 8 x 10-6 M forPu(III) were achieved. The limits of detection represent increases of 18to 33 times those achievable using a conventional 1-cm path length.Because of the much lower detection limits of the LCW, routineidentification of the oxidation states in dilute Pu solutions can bemade.
Date: February 15, 2005
Creator: Wilson, Richard E.; Hu, Yung-Jin & Nitsche, Heino
Object Type: Article
System: The UNT Digital Library
Energy efficiency improvement and cost saving opportunities forpetroleum refineries (open access)

Energy efficiency improvement and cost saving opportunities forpetroleum refineries

The petroleum refining industry in the United States is the largest in the world, providing inputs to virtually any economic sector,including the transport sector and the chemical industry. The industry operates 146 refineries (as of January 2004) around the country,employing over 65,000 employees. The refining industry produces a mix of products with a total value exceeding $151 billion. Refineries spend typically 50 percent of cash operating costs (i.e., excluding capital costs and depreciation) on energy, making energy a major cost factor and also an important opportunity for cost reduction. Energy use is also a major source of emissions in the refinery industry making energy efficiency improvement an attractive opportunity to reduce emissions and operating costs. Voluntary government programs aim to assist industry to improve competitiveness through increased energy efficiency and reduced environmental impact. ENERGY STAR (R), a voluntary program managed by the U.S. Environmental Protection Agency, stresses the need for strong and strategic corporate energy management programs. ENERGY STAR provides energy management tools and strategies for successful corporate energy management programs. This Energy Guide describes research conducted to support ENERGY STAR and its work with the petroleum refining industry.This research provides information on potential energy efficiency opportunities for petroleum refineries. …
Date: February 15, 2005
Creator: Worrell, Ernst & Galitsky, Christina
Object Type: Report
System: The UNT Digital Library
Final Technical Report - "Determining How Magnetic Helicity Injection Really Works" (open access)

Final Technical Report - "Determining How Magnetic Helicity Injection Really Works"

This research program involved direct observation of the complicated plasma dynamics underlying spheromak formation. Spheromaks are self-organizing magnetically dominated plasma configurations which potentially offer a simple, low-cost means for confining the plasma in a controlled thermonuclear fusion reactor. The spheromak source used in these studies was a coaxial co-planar magnetized plasma gun which was specifically designed to have the simplest relevant geometry. The simplicity of the geometry facilitated understanding of the basic physics and minimized confusion that would otherwise have resulted from complexities due to the experimental geometry. The coaxial plasma gun was mounted on one end of a large vacuum tank that had excellent optical access so the spheromak formation process could be tracked in detail using ultra-high speed cameras. The main accomplishments of this research program were (1) obtaining experimental data characterizing the detailed physics underlying spheromak formation and the development of new theoretical models motivated by these observations, (2) determining the relationship between spheromak physics and astrophysical jets, (3) developing a new high-speed camera diagnostic for the SSPX spheromak at the Lawrence Livermore National Lab, and (4) training graduate students and postdoctoral fellows.
Date: February 15, 2005
Creator: Bellan, Paul M.
Object Type: Report
System: The UNT Digital Library
High Current Ion Sources and Injectors for Heavy Ion Fusion (open access)

High Current Ion Sources and Injectors for Heavy Ion Fusion

Heavy ion beam driven inertial fusion requires short ion beam pulses with high current and high brightness. Depending on the beam current and the number of beams in the driver system, the injector can use a large diameter surface ionization source or merge an array of small beamlets from a plasma source. In this paper, we review the scaling laws that govern the injector design and the various ion source options including the contact ionizer, the aluminosilicate source, the multicusp plasma source, and the MEVVA source.
Date: February 15, 2005
Creator: Kwan, Joe W.
Object Type: Article
System: The UNT Digital Library
Increasing robustness of indirect drive capsule designs against short wavelength hydrodynamic instabilities (open access)

Increasing robustness of indirect drive capsule designs against short wavelength hydrodynamic instabilities

None
Date: February 15, 2005
Creator: Haan, S. W.; Herrmann, M. C.; Dittrich, T. R.; Fetterman, A. J.; Marinak, M. M.; Munro, D. H. et al.
Object Type: Article
System: The UNT Digital Library
The Influence of Selected Liquid and Soil Properties on the Propagation of Spills over Flat Permeable Surfaces (open access)

The Influence of Selected Liquid and Soil Properties on the Propagation of Spills over Flat Permeable Surfaces

In an effort to determine spill characteristics, information about a spill's spatial distribution with time is being studied. For permeable surfaces, spill phenomenology is controlled by liquid and soil properties, the most relevant of which are presented in this report. The pertinent liquid and soil properties were tabulated for ten liquids and four soils. The liquids represented an array of organic compounds, some of which are or are soon to be documented in the liquid spectra library by the Environmental Molecular Science Laboratory at Pacific Northwest National Laboratory. The soils were chosen based on ongoing surface spectra work and to represent a range of relevant soil properties. The effect of the liquid and soil properties on spill phenomenology were explored using a spill model that couples overland flow described by gravity currents with the Green-Ampt infiltration model. From the simulations, liquid viscosity was found to be a controlling liquid property in determining the amount of time a spill remains on the surface, with the surface vanish time decreasing as viscosity decreased. This was attributed to decreasing viscosity increasing both the hydraulic conductivity of the soil and allowing for the spill to more quickly spread out onto an unsaturated soil surface. …
Date: February 15, 2005
Creator: Keller, Jason M. & Simmons, Carver S.
Object Type: Report
System: The UNT Digital Library
An integrative approach to energy, carbon, and redox metabolism in the cyanobacterium Synechocystis sp. PCC 6803 (open access)

An integrative approach to energy, carbon, and redox metabolism in the cyanobacterium Synechocystis sp. PCC 6803

The team of the Fellowship for Interpretation of Genomes (FIG) under the leadership of Ross Overbeek, began working on this Project in November 2003. During the previous year, the Project was performed at Integrated Genomics Inc. A transition from the industrial environment to the public domain prompted us to adjust some aspects of the Project. Notwithstanding the challenges, we believe that these adjustments had a strong positive impact on our deliverables. Most importantly, the work of the research team led by R. Overbeek resulted in the deployment of a new open source genomic platform, the SEED (Specific Aim 1). This platform provided a foundation for the development of CyanoSEED a specialized portal to comparative analysis and metabolic reconstruction of all available cyanobacterial genomes (Specific Aim 3). The SEED represents a new generation of software for genome analysis. Briefly, it is a portable and extendable system, containing one of the largest and permanently growing collections of complete and partial genomes. The complete system with annotations and tools is freely available via browsing or via installation on a user's Mac or Linux computer. One of the important unique features of the SEED is the support of metabolic reconstruction and comparative genome analysis …
Date: February 15, 2005
Creator: Ross Overbeek, Veronika Fonstein, Andrei Osterman, Svetlana Gerdes, Olga Vassieva, Olga Zagnitko, Dmitry Rodionov
Object Type: Report
System: The UNT Digital Library
Inverse Scattering Approach to Improving Pattern Recognition (open access)

Inverse Scattering Approach to Improving Pattern Recognition

The Helmholtz machine provides what may be the best existing model for how the mammalian brain recognizes patterns. Based on the observation that the ''wake-sleep'' algorithm for training a Helmholtz machine is similar to the problem of finding the potential for a multi-channel Schrodinger equation, we propose that the construction of a Schrodinger potential using inverse scattering methods can serve as a model for how the mammalian brain learns to extract essential information from sensory data. In particular, inverse scattering theory provides a conceptual framework for imagining how one might use EEG and MEG observations of brain-waves together with sensory feedback to improve human learning and pattern recognition. Longer term, implementation of inverse scattering algorithms on a digital or optical computer could be a step towards mimicking the seamless information fusion of the mammalian brain.
Date: February 15, 2005
Creator: Chapline, G & Fu, C
Object Type: Article
System: The UNT Digital Library
Lessons Learned from an External Review of the Savannah River Site Saltstone Performance Assessment Program (open access)

Lessons Learned from an External Review of the Savannah River Site Saltstone Performance Assessment Program

None
Date: February 15, 2005
Creator: Cook, James R.
Object Type: Article
System: The UNT Digital Library
Modeling Antimortar Lethality by a Solid-State Heat-Capacity Laser (open access)

Modeling Antimortar Lethality by a Solid-State Heat-Capacity Laser

We have studied the use of a solid-state heat-capacity laser (SSHCL) in mortar defense. This type of laser, as built at LLNL, produces high-energy pulses with a wavelength of about 1 {micro}m and a pulse repetition rate of 200 Hz. Currently, the average power is about 26 kW. Our model of target interactions includes optical absorption, two-dimensional heat transport in the metal casing and explosive, melting, wind effects (cooling and melt removal), high-explosive reactions, and mortar rotation. The simulations continue until HE initiation is reached. We first calculate the initiation time for a range of powers on target and spot sizes. Then we consider an engagement geometry in which a mortar is fired at an asset defended by a 100-kW SSHCL. Propagation effects such as diffraction, turbulent broadening, scattering, and absorption are calculated for points on the trajectory, by means of a validated model. We obtain kill times and fluences, as functions of the rotation rate. These appear quite feasible.
Date: February 15, 2005
Creator: Boley, C D & Rubenchik, A M
Object Type: Article
System: The UNT Digital Library