Hard target penetrator explosive development optimization of fragment, blast and survivability properties of explosives for hard target applications (open access)

Hard target penetrator explosive development optimization of fragment, blast and survivability properties of explosives for hard target applications

Several new explosives have been developed for hard target and related applications. Materials having energy densities as high as 20 KJ/cc have been made. Mid-scale field trials have been carried out at Eglin Air Force Base. Fragmentation improvements 150% that of Tritonal have been attained.
Date: May 1, 1997
Creator: Simpson, R. L., LLNL
Object Type: Article
System: The UNT Digital Library
Properties of b {anti b} Production at the Tevatron (open access)

Properties of b {anti b} Production at the Tevatron

The authors present a number of recent results obtained at the Fermilab Tevatron for b{bar b} production in p{bar p} interactions. The preliminary CDF and D0 measurements of the inclusive b-quark production cross section at {radical}s = 630 GeV are compared with the UA1 results and the next-to-leading order QCD predictions. These results are used to compute the ratio of the cross sections at 630 GeV to 1800 GeV. The CDF results on the B meson differential cross section and {Lambda}{sub b}{sup 0} baryon production and decay properties at {radical}s = 1800 GeV are also presented.
Date: May 1, 1997
Creator: Stichelbaut, Frederic
Object Type: Article
System: The UNT Digital Library
Distribution of the Chuckwalla, Western Burrowing Owl, and Six Bat Species on the Nevada Test Site (open access)

Distribution of the Chuckwalla, Western Burrowing Owl, and Six Bat Species on the Nevada Test Site

Field Surveys were conducted in 1996 to determine the current distribution of several animal species of concern on the Nevada Test Site (NTS). They included the chuckwall (Sauromalus obesus), western burrowing owl (Speotyto cunicularia), and six species of bats. Nineteen chuckwallas and 118 scat locations were found during the chuckwalla field study. Eighteen western burrowing owls were found at 12 sighting locations during the 1996 field study. Of the eleven bat species of concern which might occur on the NTS, five, and possibly six, were captured during this survey. The U.S. Department of Energy, Nevada Operations Office, takes certain management actions to protect and conserve the chuckwalla, western burrowing owl, and bats on the NTS. These actions are described and include: (1) conducting surveys at sites of proposed land-disturbing activities (2) altering projects whenever possible to avoid or minimize impacts to these species (3) maintaining a geospatial database of known habitat for species of concern (4) sharing sighting and trap location data gathered on the NTS with other local land and resource managers, and (5) conducting periodic field surveys to monitor these species distribution and relative abundance on the NTS.
Date: May 1, 1997
Creator: Willis, Cathy A.
Object Type: Report
System: The UNT Digital Library
Nevada Test Site Wetlands Assessment (open access)

Nevada Test Site Wetlands Assessment

This report identifies 16 Nevada Test Site (NTS) natural water sources that may be classified by the U.S. Army Corps of Engineers (USACE) as jurisdictional wetlands and identifies eight water sources that may be classified as waters of the United States. These water sources are rare, localized habitats on the NTS that are important to regional wildlife and to isolated populations of water tolerant plants and aquatic organisms. No field investigations on the NTS have been conducted in the past to identify those natural water sources which would be protected as rare habitats and which may fall under regulatory authority of the Clean Water Act (CWA) of 1997. This report identifies and summarizes previous studies of NTS natural water sources, and identifies the current DOE management practices related to the protection of NTS wetlands. This report also presents management goals specific for NTS wetlands that incorporate the intent of existing wetlands legislation, the principles of ecosystem management, and the interests of regional land managers and other stakeholders.
Date: May 1, 1997
Creator: Hansen, D. J.
Object Type: Report
System: The UNT Digital Library
Realtime tune measurements in slow-cycling accelerators (open access)

Realtime tune measurements in slow-cycling accelerators

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Date: May 1, 1997
Creator: Herrup, D.
Object Type: Article
System: The UNT Digital Library
Optics elements for modeling electrostatic lenses and accelerator components: I. envzel lenses (open access)

Optics elements for modeling electrostatic lenses and accelerator components: I. envzel lenses

A set of optical models for a variety of electrostatic lenses and accelerator columns has been developed for the computer code TRACE 3-D. TRACE 3-D is an envelope (matrix) code including space charge often used to model bunched beams in magnetic transport systems and radiofrequency (RF) accelerators when the effects of beam current may be important. Several new matrix models have been developed that allow the code to be used for modeling beam lines and accelerators with electrostatic components. The new models include: (1) three einzel lenses, (2) two accelerator columns, (3) three electrostatic deflectors (prisms), and (4) an electrostatic quadrupole. A prescription for setting up the initial beam appropriate to modeling 2-D (continuous) beams has also been developed. The new models for (1) are described in this paper, selected comparisons with other calculations are presented, and a beamline application is summarized.
Date: May 1, 1997
Creator: Gillespie, G. H., G. H. Gillespie Associates, Inc.
Object Type: Article
System: The UNT Digital Library
Beam-beam simulations with crossing angle in TeV33 (open access)

Beam-beam simulations with crossing angle in TeV33

In this report is considered effects of finite crossing angle at collision point on beam dynamics in the Tevatron collider upgrade (TEV33). Impact of the beam-beam interaction on beam sizes, particles diffusion and luminosity is studied with use of computer simulations. Parameter space forr better collider performance is proposed.
Date: May 1, 1997
Creator: Shiltsev, V. D.
Object Type: Article
System: The UNT Digital Library
Investigation on Durability and Reactivity of Promising Metal Oxide Sorbents During Sulfidation and Regeneration (open access)

Investigation on Durability and Reactivity of Promising Metal Oxide Sorbents During Sulfidation and Regeneration

Research activities and efforts of this research project were concentrated on formulating various metal oxide sorbents with various additives under various formulation conditions, conducting experiments on initial reactivity of formulated sorbents with hydrogen sulfide, and testing hardness of formulated sorbents. Experiments on reactivity of formulated metal oxide sorbents with wet hydrogen sulfide contained in a simulated coal gas mixture were carried out for 120 seconds at 550 o C (see Table 1) to evaluate reactivity of formulated sorbents with hydrogen sulfide. Hardness of formulated sorbents was evaluated in addition to testing their reactivity with hydrogen sulfide. A typical simulated coal gas mixture consists of 9107-ppm hydrogen sulfide (0.005 g; 1 wt %), 0.085-g water (15.84 wt %), 0.0029-g hydrogen (0.58 wt %), and 0.4046-g nitrogen (81.34 wt%).
Date: May 1, 1997
Creator: Kwon, K. C.
Object Type: Report
System: The UNT Digital Library
Effects of Surface Chemistry on the Porous Structure of Coal (open access)

Effects of Surface Chemistry on the Porous Structure of Coal

In this report, 129 Xe nuclear magnetic resonance spectroscopy of xenon gas adsorbed in coal is used to describe some poorly understood features of coal microporous structure, particularly in establishing that a connected network exists, the type of connectivity, and its changes with the rank of coal. Micropore size scale and distribution are also considered. Two methods are developed which are new and versatile tools for the investigation of porous structure. Both utilize xenon gas that is in motion, while undergoing diffusion or exchange in coal, to describe the connectivity of the micropore structure of coal. Time tracking of the adsorption process by NMR, selective saturation, and saturation transfer techniques were used to obtain new information on the coal rank dependence of porous structure. In addition, an existing 129 Xe chemical shift-pore diameter model was used to calculate micropore diameters for coals, as well as for a microporous carbon, before and after pore-size alteration. In the initial study performed, straightforward 129 Xe NMR spectra at equilibrium xenon adsorption at a series of pressures were acquired for a rank-varied set of six coals. Acquisition of the NMR signal as an echo was tested and found to improve spectral quality. The spectra …
Date: May 1, 1997
Creator: Radovic, Ljubisa R. & Hatcher, Patrick G.
Object Type: Report
System: The UNT Digital Library
Development of a Comprehensive Weld Process Model (open access)

Development of a Comprehensive Weld Process Model

This cooperative research and development agreement (CRADA) between Concurrent Technologies Corporation (CTC) and Lockheed Martin Energy Systems (LMES) combines CTC's expertise in the welding area and that of LMES to develop computer models and simulation software for welding processes. This development is of significant impact to the industry, including materials producers and fabricators. The main thrust of the research effort was to develop a comprehensive welding simulation methodology. A substantial amount of work has been done by several researchers to numerically model several welding processes. The primary drawback of most of the existing models is the lack of sound linkages between the mechanistic aspects (e.g., heat transfer, fluid flow, and residual stress) and the metallurgical aspects (e.g., microstructure development and control). A comprehensive numerical model which can be used to elucidate the effect of welding parameters/conditions on the temperature distribution, weld pool shape and size, solidification behavior, and microstructure development, as well as stresses and distortion, does not exist. It was therefore imperative to develop a comprehensive model which would predict all of the above phenomena during welding. The CRADA built upon an already existing three- dimensional (3-D) welding simulation model which was developed by LMES which is capable of …
Date: May 1, 1997
Creator: Radhakrishnan, B. & Zacharia, T.
Object Type: Report
System: The UNT Digital Library
Fundamental Study of Low NOx Combustion Fly Ash Utilization (open access)

Fundamental Study of Low NOx Combustion Fly Ash Utilization

This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over forty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the …
Date: May 1, 1997
Creator: Suubert, E. M.; Kuloats, I.; Smith, K.; Sabanegh, N.; Hurt, R.H.; Lilly, W. D. et al.
Object Type: Report
System: The UNT Digital Library
Dimensional stability and tensile strength of irradiated Nicalon-CG and Hi-Nicalon SiC fibers (open access)

Dimensional stability and tensile strength of irradiated Nicalon-CG and Hi-Nicalon SiC fibers

Nicalon-CG and Hi-Nicalon fibers were characterized by measuring their length, density, and tensile strength in the unirradiated, thermal annealed, and irradiated conditions. The irradiation was conducted in the EBR-II to a dose of 43 dpa-SiC at a nominal irradiation temperature of 1,000 C. The annealed specimens were held at 1,010 C for 165 days to approximately duplicate the thermal exposure of the irradiated specimens. The results indicate the fibers that perform best in an irradiation environment are those that approach stoichiometric and crystalline SiC. Hi-Nicalon exhibited negligible densification, accompanied by an increase in tensile strength after irradiation. Nicalon-CG possessed a higher tensile strength than hi-Nicalon in the unirradiated condition, but was significantly weakened in the annealed and irradiated conditions. In addition, Nicalon-CG exhibited unacceptable irradiation-induced shrinkage. Loss o fiber tensile strength after irradiation is shown to reduce the flexural strength of irradiated composites and Nicalon-CG fiber shrinkage observed in irradiated composites.
Date: May 1, 1997
Creator: Youngblood, G. E.; Henager, C. H., Jr.; Senor, D. J.; Newsome, G. A. & Woods, J. J.
Object Type: Report
System: The UNT Digital Library
Space-charge forces of a DC beam in a continuous bend (open access)

Space-charge forces of a DC beam in a continuous bend

It has been shown that the net space-charge forces for a dc beam with space-charge potential depression in a bend have the usual inverse energy square dependence to the first order in the beam radius a over the bend radius R. We extend the analysis to the second order in a/R and allow the beam to have a small transverse displacement. The net space-charge forces are no longer cancelled to inverse energy square factor. The non-cancelled part of self-induced magnetic forces are at the second order in a/R and independent of the beam energy. The nonlinear parts of these forces are much larger than that of the usual inverse energy square forces. Scaling laws for emittance growth caused by the curvature of the beam and a transverse beam displacement, respectively, are presented.
Date: May 1, 1997
Creator: Chen, Yu-Jiuan
Object Type: Article
System: The UNT Digital Library
Strategy for thermo-gravimetric analysis of K East fuel samples (open access)

Strategy for thermo-gravimetric analysis of K East fuel samples

A strategy was developed for the Thermo-Gravimetric Analysis (TGA) testing of K East fuel samples for oxidation rate determinations. Tests will first establish if there are any differences for dry air oxidation between the K West and K East fuel. These tests will be followed by moist inert gas oxidation rate measurements. The final series of tests will consider pure water vapor i.e., steam.
Date: May 1, 1997
Creator: Lawrence, L.A.
Object Type: Report
System: The UNT Digital Library
DEGAS 2 neutral transport modeling of high density, low temperature plasmas (open access)

DEGAS 2 neutral transport modeling of high density, low temperature plasmas

Neutral transport in the high density, low temperature plasma regime is examined using the DEGAS 2 Monte Carlo neutral transport code. DEGAS 2 is shown to agree with an analytic fluid neutral model valid in this regime as long as the grid cell spacing is less than twice the neutral mean-free path. Using new atomic physics data provided by the collisional radiative code CRAMD, DEGAS 2 is applied to a detached Alcator C-Mod discharge. A model plasma with electron temperature {approximately}1 eV along detached flux tubes, between the target and the ionization front, is used to demonstrate that recombination is essential to matching the experimental data. With the CRAMD data, {approximately}20% of the total recombination is due to molecular activated recombination.
Date: May 1, 1997
Creator: Stotler, D. P.; Karney, C. F. F. & Pigarov, A. Y.
Object Type: Report
System: The UNT Digital Library
Modeling of InGaSb thermophotovoltaic cells and materials (open access)

Modeling of InGaSb thermophotovoltaic cells and materials

A closed form computer program has been developed for the simulation and optimization of In{sub x}Ga{sub 1{minus}x}Sb thermophotovoltaic cells operating at room temperature. The program includes material parameter models of the energy bandgap, optical absorption constant, electron and hole mobility, intrinsic carrier concentration and index of refraction for any composition of GaInSb alloys.
Date: May 1, 1997
Creator: Zierak, M.; Borrego, J. M.; Bhat, I.; Gutmann, R. J. & Charache, G.
Object Type: Report
System: The UNT Digital Library
Electrical and optical properties of degenerately doped N-type In{sub x}Ga{sub 1{minus}x}As (open access)

Electrical and optical properties of degenerately doped N-type In{sub x}Ga{sub 1{minus}x}As

Degenerately-doped (> 10{sup 19} cm{sup {minus}3}) n-type In{sub x}Ga{sub 1{minus}x}As (x > 0.53) possesses a number of intriguing electrical and optical properties relevant to electro-optic devices and thermophotovoltaic devices in particular. Due to the low electron effective mass of this material and the demonstrated ability to incorporate n-type dopants into the mid-10{sup 19} cm{sup {minus}3} range, both the Moss-Burnstein bandgap shift and plasma reflection characteristics are particularly dramatic. These properties are investigated for In{sub x}Ga{sub 1{minus}x}As as a function of doping concentration, dopant type, and growth conditions. For undoped InGaAs with a nominal bandgap of 0.6 eV, doping this material to 5 {times} 10{sup 19} cm{sup {minus}3} increased the effective optical bandgap to 1.1 eV and has a plasma turn-on wavelength of 5 microns. This filter was coupled to a non-absorbing interference filter, creating a functional tandem filter for thermophotovoltaic applications.
Date: May 1, 1997
Creator: Charache, G. W.; DePoy, D. M. & Egley, J. L.
Object Type: Article
System: The UNT Digital Library
DVD - digital versatile disks (open access)

DVD - digital versatile disks

An international standard has emerged for the first true multimedia format. Digital Versatile Disk (by its official name), you may know it as Digital Video Disks. DVD has applications in movies, music, games, information CD-ROMS, and many other areas where massive amounts of digital information is needed. Did I say massive amounts of data? Would you believe over 17 gigabytes on a single piece of plastic the size of an audio-CD? That`s the promise, at least, by the group of nine electronics manufacturers who have agreed to the format specification, and who hope to make this goal a reality by 1998. In this major agreement, which didn`t come easily, the manufacturers will combine Sony and Phillip`s one side double-layer NMCD format with Toshiba and Matsushita`s double sided Super-Density disk. By Spring of this year, they plan to market the first 4.7 gigabyte units. The question is: Will DVD take off? Some believe that read-only disks recorded with movies will be about as popular as video laser disks. They say that until the eraseable/writable DVD arrives, the consumer will most likely not buy it. Also, DVD has a good market for replacement of CD- Roms. Back in the early 80`s, the …
Date: May 1, 1997
Creator: Gaunt, R.
Object Type: Article
System: The UNT Digital Library
Evaluation of impact tests of solid steel billet onto concrete pads, and application to generic ISFSI storage cask for tipover and side drop (open access)

Evaluation of impact tests of solid steel billet onto concrete pads, and application to generic ISFSI storage cask for tipover and side drop

Twelve tests were performed at LLNL to assess loading conditions on a spent fuel casts for side drops, end drops and tipover events. The tests were performed with a 1/3-scale model concrete pad to benchmark the structural analysis code DYNA3D. The side drop and tipover test results are discussed in this report. The billet and test pad were modified with DYNA3D using material properties and techniques used in earlier tests. The peak or maximum deceleration test results were compared to the simulated analytical results. It was concluded that an analytical model based on DYNA3D code and has been adequately benchmarked for this type of application. A generic or represented cask was modified with the DYNA3D code and evaluated for ISFSI side drop and tipover events. The analytical method can be applied to similar casks to estimate impact loads on storage casks resulting from low-velocity side or tip impacts onto concrete storage pads.
Date: May 1, 1997
Creator: Witte, M.C.; Chen, T.F.; Murty, S.S.; Tang, D.T.; Mok, G.C.; Fischer, L.E. et al.
Object Type: Article
System: The UNT Digital Library
TPV efficiency measurements and predictions for a closed cavity geometry (open access)

TPV efficiency measurements and predictions for a closed cavity geometry

A thermophotovoltaic (TPV) efficiency measurement, within a closed cavity, is an integrated test which incorporates four fundamental parameters of TPV direct energy conversion. These are: (1) the TPV devices, (2) spectral control, (3) a radiation/photon source, and (4) closed cavity geometry effects. The overall efficiency of the TPV device is controlled by the TP cell performance, the spectral control characteristics, the radiator temperature and the geometric arrangement. Controlled efficiency measurements and predictions provide valuable feedback on all four. This paper describes and compares two computer codes developed to model 16, 1 cm{sup 2} TPV cells (in a 4 x 4 configuration) in a cavity geometry. The first code, subdivides the infrared spectrum into several bands and then numerically integrates over the spectrum to provide absorbed heat flux and cell electrical output performance predictions (assuming infinite parallel plates). The second code, utilizes a Monte Carlo Photon Transport code that tracks photons, from birth at the radiation source, until they either escape or are absorbed. Absorption depends upon energy dependent reflection probabilities assigned to every geometrical surface within the cavity. The model also has the capability of tallying above and below bandgap absorptions (as a function of location) and can support various …
Date: May 1, 1997
Creator: Gethers, C. K.; Ballinger, C. T.; Postlethwait, M. A.; DePoy, D. M. & Baldasaro, P. F.
Object Type: Article
System: The UNT Digital Library
Color spaces in digital video (open access)

Color spaces in digital video

Whether it`s photography, computer graphics, publishing, or video; each medium has a defined color space, or gamut, which defines the extent that a given set of RGB colors can be mixed. When converting from one medium to another, an image must go through some form of conversion which maps colors into the destination color space. The conversion process isn`t always straight forward, easy, or reversible. In video, two common analog composite color spaces are Y`tjv (used in PAL) and Y`IQ (used in NTSC). These two color spaces have been around since the beginning of color television, and are primarily used in video transmission. Another analog scheme used in broadcast studios is Y`, R`-Y`, B`-Y` (used in Betacam and Mll) which is a component format. Y`, R`-Y`,B`-Y` maintains the color information of RGB but in less space. From this, the digital component video specification, ITU-Rec. 601-4 (formerly CCIR Rec. 601) was based. The color space for Rec. 601 is symbolized as Y`CbCr. Digital video formats such as DV, Dl, Digital-S, etc., use Rec. 601 to define their color gamut. Digital composite video (for D2 tape) is digitized analog Y`UV and is seeing decreased use. Because so much information is contained in …
Date: May 1, 1997
Creator: Gaunt, R.
Object Type: Article
System: The UNT Digital Library
Minority-carrier transport in InGaAsSb thermophotovoltaic diodes (open access)

Minority-carrier transport in InGaAsSb thermophotovoltaic diodes

Uncoated InGaAsSb/GaSb thermophotovoltaic (TPV) diodes with 0.56 eV (2.2 {micro}m) bandgaps exhibit external quantum efficiencies of 59% at 2 {micro}m. The devices have electron diffusion lengths as long as 29 {micro}m in 8-{micro}m-wide p-InGaAsSb layers and hole diffusion lengths of 3 {micro}m in 6-{micro}m-wide n-InGaAsSb layers. The electron and hole diffusion lengths appear to increase with increasing p- and n-layer widths. At 632.8 nm the internal quantum efficiencies of diodes with 1- to 8-{micro}m-wide p-layers are above 89% and are independent of the p-layer width, indicating long electron diffusion lengths. InGaAsSb has, therefore, excellent minority carrier transport properties that are well suited to efficient TPV diode operation. The structures were grown by molecular-beam epitaxy.
Date: May 1, 1997
Creator: Martinelli, R. U.; Garbuzov, D. Z.; Lee, H.; Morris, N.; Odubanjo, T. & Connolly, J. C.
Object Type: Report
System: The UNT Digital Library