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High resolution difference schemes for compressible gas dynamics (open access)

High resolution difference schemes for compressible gas dynamics

The advantages and disadvantages of four new high-resolution difference schemes, namely the von Neumann-Richtmyer, Godunovs, MUSCL and Glimms, for mathematically representing physical conditions in compressible gas flows are compared. (LCL)
Date: July 30, 1980
Creator: Woodward, P. & Colella, P.
System: The UNT Digital Library
Future engineering needs of mirror fusion reactors (open access)

Future engineering needs of mirror fusion reactors

Fusion research has matured during the last decade and significant insight into the future program needs has emerged. While some will properly note that the crystal ball is cloudy, it is equally important to note that the shape and outline of our course is discernable. In this short summary paper, I will draw upon the National Mirror Program Plan for mirror projects and on available design studies of these projects to put the specific needs of the mirror program in perspective.
Date: July 30, 1982
Creator: Thomassen, K.I.
System: The UNT Digital Library
Double-mode pulsation (open access)

Double-mode pulsation

Double mode pulsation is a very pervasive phenomenon in stars all over the Hertzsprung-Russell diagram. In order of increasing radius, examples are: ZZ Ceti stars, the sun, the delta Scuti stars, RR Lyrae variables, the ..beta.. Cephei variables and those related to them, Cepheids, and maybe even the Mira stars. These many modes have been interpreted as both radial and nonradial modes, but in many cases the actual mode has not been clearly identified. Yellow giants seem to be the most simple pulsators with a large majority of the RR Lyrae variables and Cepheids showing only one pulsation period. We limit this review to those very few cases for classical Cepheids and RR Lyrae variables which display two modes. For these we know many facts about these stars, but the actual cause of the pulsation in two modes simultaneously remains unknown.
Date: July 30, 1982
Creator: Cox, A. N.
System: The UNT Digital Library
Tritium related safety considerations for mirror upgrades (open access)

Tritium related safety considerations for mirror upgrades

One of the primary objectives of the MFTF-B upgrades is to demonstrate the technology of tritium breeding in a reactor-like configuration. This requires use and processing of tritium, involving an inventory of several hundred grams at the plant. This paper reviews the results of a preliminary assessment of the radiation hazard associated with the handling of tritium. The radiation dose consequences due to tritium release from normal operation and due to postulated accidents on plant personnel and the public were assessed. Maximum credible (probability < 10/sup -3/, but > 10/sup -7//yr) accidental releases were estimated to be 10 gm in the reactor building and 100 gm in the tritium-processing building. Higher probability (> 10/sup -3//yr) accidents or component failures would result in much smaller releases. In the reactor building, the most severe accident would result from the rupture of a plasma exhaust duct from the end cell or the tritium feed pipe to the neutral beam injector, accompanied by a fire. In the tritium processing building, the most severe accident would be the rupture of the Isotope Separation System (ISS) distillation columns and vacuum jackets accompanied by a fire.
Date: November 30, 1983
Creator: Ghose, S.K.
System: The UNT Digital Library
NOVA laser facility for inertial confinement fusion (open access)

NOVA laser facility for inertial confinement fusion

The NOVA laser consists of ten beams, capable of concentrating 100 to 150 kJ of energy (in 3 ns) and 100 to 150 TW of power (in 100 ps) on experimental targets by 1985. NOVA will also be capable of frequency converting the fundamental laser wavelength (1.05 ..mu..m) to its second (0.525 ..mu..m) or third (0.35 ..mu..m) harmonic. This additional capability (80 to 120 kJ at 0.525 ..mu..m, 40 to 70 kJ at 0.35 ..mu..m) was approved by the US Department of Energy (DOE) in April 1982. These shorter wavelengths are much more favorable for ICF target physics. Current construction status of the NOVA facility, intended for completion in the autumn of 1984, will be presented.
Date: November 30, 1983
Creator: Simmons, W.W.
System: The UNT Digital Library
Cancer risks and neutron RBE's from Hiroshima and Nagasaki (open access)

Cancer risks and neutron RBE's from Hiroshima and Nagasaki

The new radiation dose estimates for Hiroshima and Nagasaki are here combined with epidemiologic data from the A-bomb survivors and examined radiobiologically for compatability with other human and experimental data. The new doses show certain improvements over the original T65 doses. However, they suggest for chronic granulocytic leukemia, total malignancies, and chromosome aberrations, at neutron doses of 1 rad, RBEs in excess of 100, higher than expected from other findings. This and other indications suggest that either there are unrecognized systematic problems with the various radiobiological data, or the new doses are deficient in neutrons for Hiroshima, by a factor of about five. If in fact there were actually some 5-fold more dose from neutrons at Hiroshima than estimated by the new calculations, the RBEs would agree well with laboratory results, and other inconsistencies would largely disappear. Cancer risks are estimated for neutrons from the new doses and are compared with those estimated from radiobiologically reconciled doses (the new doses adjusted by adding approximately 5-fold more neutrons). The latter estimates appear more reasonable. For low-LET radiation, cancer risk estimates are altered very little by the new dose estimates for Nagasaki.
Date: April 30, 1982
Creator: Dobson, R.L. & Straume, T.
System: The UNT Digital Library
Nuclear criticality information system (open access)

Nuclear criticality information system

The nuclear criticality safety program at LLNL began in the 1950's with a critical measurements program which produced benchmark data until the late 1960's. This same time period saw the rapid development of computer technology useful for both computer modeling of fissile systems and for computer-aided management and display of the computational benchmark data. Database management grew in importance as the amount of information increased and as experimental programs were terminated. Within the criticality safety program at LLNL we began at that time to develop a computer library of benchmark data for validation of computer codes and cross sections. As part of this effort, we prepared a computer-based bibliography of criticality measurements on relatively simple systems. However, it is only now that some of these computer-based resources can be made available to the nuclear criticality safety community at large. This technology transfer is being accomplished by the DOE Technology Information System (TIS), a dedicated, advanced information system. The NCIS database is described.
Date: November 30, 1981
Creator: Koponen, B. L. & Hampel, V. E.
System: The UNT Digital Library
Investigation of the cryogenic mechanical properties of low thermal-expansion superalloys (open access)

Investigation of the cryogenic mechanical properties of low thermal-expansion superalloys

Four Fe-based superalloys, JBK-75, Incoloy 903, Incoloy 905, and Incoloy 909 were evaluated as tube materials for ICCS Nb/sub 3/Sn superconductors. Evaluation consisted of 4-K tensile and elastic-plastic fracture-toughness testing, and a microstructural characterization of unwelded and autogenously gas-tungsten-arc welded sheet given a simulated postweld processing treatment of 15% cold reduction by rolling followed by a Nb/sub 3/Sn-reaction heat treatment of 96 hours at 700/sup 0/C plus 48 hours at 730/sup 0/C. Results indicate that JBK-75 and Incoloy 903 showed satisfactory combinations of strength and toughness for ICCS tube use requiring long Nb/sub 3/Sn-reaction heat treatments. Incoloy 905 welds and 909 showed unacceptable fracture toughness. Results are discussed in terms of microstructural changes caused by the extended Nb/sub 3/Sn-reaction heat treatment.
Date: July 30, 1985
Creator: Summers, L.T. & Dalder, E.N.C.
System: The UNT Digital Library
Mirror Fusion Test Facility: an intermediate device to a mirror fusion reactor (open access)

Mirror Fusion Test Facility: an intermediate device to a mirror fusion reactor

The Mirror Fusion Test Facility (MFTF-B) now under construction at Lawrence Livermore National Laboratory represents more than an order-of-magnitude step from earlier magnetic-mirror experiments toward a future mirror fusion reactor. In fact, when the device begins operating in 1986, the Lawson criteria of ntau = 10/sup 14/ cm/sup -3/.s will almost be achieved for D-T equivalent operation, thus signifying scientific breakeven. Major steps have been taken to develop MFTF-B technologies for tandem mirrors. Steady-state, high-field, superconducting magnets at reactor-revelant scales are used in the machine. The 30-s beam pulses, ECRH, and ICRH will also introduce steady-state technologies in those systems.
Date: March 30, 1983
Creator: Karpenko, V.N.
System: The UNT Digital Library
Optical pumping of hot phonons in GaAs (open access)

Optical pumping of hot phonons in GaAs

Optical pumping of hot LO phonons in GaAs has been studied as a function of the excitation photon frequency. The experimental results are in good agreement with a model calculation which includes both inter- and intra-valley electron-phonon scatterings. The GAMMA-L and GAMMA-X intervalley electron-phonon interactions in GaAs have been estimated.
Date: June 30, 1982
Creator: Collins, C.L. & Yu, P.Y.
System: The UNT Digital Library
Off-nadir optical remote sensing from satellites for vegetation identification (open access)

Off-nadir optical remote sensing from satellites for vegetation identification

Today's satellite remote sensing systems rely heavily on spectral signatures for scene identification from nadir observations. We propose to use angular signatures as complementary scene identifiers when off-nadir sensing is possible. Specifically, the hot spot (Heiligenschein) of plant canopies is recognized as an atmosphere-invariant angular reflectance signature that carries information about the plant stand architecture which may be useful for instant crop identification from off-nadir satellite measurements.
Date: May 30, 1986
Creator: Gerstl, S.A.W.
System: The UNT Digital Library
Design of a separator/neutralizer to limit impurities and non-primary species in the Mirror Fusion Test Facility (open access)

Design of a separator/neutralizer to limit impurities and non-primary species in the Mirror Fusion Test Facility

The optimum plasma for the tandem Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory (LLNL) is very sensitive to heavy contaminates, such as oxygen and metals. Unfortunately the current neutral beam sources generate not only high energy deuterium particles but also high energy oxygen particles. A new MFTF-B separator/neutralizer has been designed to filter out the unwanted oxygen and allow only primary species neutrals to reach the plasma.
Date: November 30, 1983
Creator: Goldner, A.I.
System: The UNT Digital Library
5cm aperture dipole studies (open access)

5cm aperture dipole studies

The results obtained during the evolution of the design, construction, and testing program of the design ''B'' dipole are presented here. Design ''B'' is one of the original three competing designs for the Superconducting Super Collider ''SSC'' arc dipoles. The final design parameters were as follows: air cored (less than a few percent of the magnetic field derived from any iron present), aluminum collared, two layered winding, 5.5T maximum operating field, and a 5 cm cold aperture. There have been fourteen 64 cm long 5 cm aperture model dipoles cold tested (at 4.3K and less) in this program so far. There was a half length full size (6m) mechanical analog (M-10) built and tested to check the cryostat's mechanical design under ramping and quench conditions. Several deviations from the ''Tevatron'' dipole fabrication technique were incorporated, for example the use of aluminum collars instead of stainless steel. The winding technique variations explored were ''dry welding,'' a technique with the cable covered with Kapton insulation only and ''wet winding'' where the Kapton was covered with a light coat of ''B'' stage epoxy. Test data include quench currents, field quality (Fourier multipole co-efficients), coil magnetization, conductor current performance, and coil loading. Quench current, …
Date: September 30, 1986
Creator: McInturff, A.D.; Bossert, R.; Carson, J.; Fisk, H.E.; Hanft, R.; Kuchnir, M. et al.
System: The UNT Digital Library
Production and survival of /sup 99/Tc in He-shell recurrent thermal pulses (open access)

Production and survival of /sup 99/Tc in He-shell recurrent thermal pulses

After a brief introduction to the present state of art of nuclear beta-decay studies in astrophysics, we report our recent work on the long-standing /sup 99/Tc problem. Having combined a detailed study of the recurrent He-shell thermal-pulse, third dredge-up episodes in a 2.25 M/sub solar/ star and an s-process network calculation, we show that a substantial amount of /sup 99/Tc can be produced by the s-process and can survive to be dredged up to the stellar surface. We stress that the factual observation of /sup 99/Tc at the surface of certain stars does not necessarily preclude the /sup 22/Ne(..cap alpha..,n)/sup 25/Mg reaction from remaining as the neutron source for the s-process. The calculated surface abundances of /sup 99/Tc and elements with neighboring atomic numbers are compared with observations. 43 refs., 5 figs.
Date: May 30, 1985
Creator: Takahashi, K.; Mathews, G. J.; Ward, R. A. & Becker, S. A.
System: The UNT Digital Library
Standard method for economic analyses of inertial confinement fusion power plants (open access)

Standard method for economic analyses of inertial confinement fusion power plants

A standard method for calculating the total capital cost and the cost of electricity for a typical inertial confinement fusion electric power plant has been developed. A standard code of accounts at the two-digit level is given for the factors making up the total capital cost of the power plant. Equations are given for calculating the indirect capital costs, the project contingency, and the time-related costs. Expressions for calculating the fixed charge rate, which is necessary to determine the cost of electricity, are also described. Default parameters are given to define a reference case for comparative economic analyses.
Date: May 30, 1986
Creator: Meier, W. R.
System: The UNT Digital Library
Improved 50 ps response x-ray detector with optical applications (open access)

Improved 50 ps response x-ray detector with optical applications

We have improved the impulse response characteristics of the LLNL 50 ps detector significantly. The detector has also been improved mechanically to permit much greater ease of assembly and repair. We are investigating modified versions of this design for optical applications. The detector was developed to complement the recording capability of our Thomson-CSF 4 GHz oscilloscopes in laser driven ICF fusion experiments research.
Date: September 30, 1981
Creator: Campbell, D.; Tirsell, G. & Laird, W.
System: The UNT Digital Library
The Advanced Light Source: A new 1. 5 GeV synchrotron radiation facility at the Lawrence Berkeley Laboratory (open access)

The Advanced Light Source: A new 1. 5 GeV synchrotron radiation facility at the Lawrence Berkeley Laboratory

The Advanced Light Source (ALS), now under construction at the Lawrence Berkeley Laboratory, is being planned as a national user facility for the production of high-brightness and partially coherent x-ray and ultraviolet synchrotron radiation. The ALS is based on a low-emittance electron storage ring optimized for operation at 1.5 GeV with insertion devices in 11 long straight sections and up to 48 bend-magnet ports. High-brightness photon beams, from less than 10 eV to more than 1 keV, will be produced by undulators, thereby providing many research opportunities in materials and surface science, biology, atomic physics and chemistry. Wigglers and bend magnets will provide high-flux, broad-band radiation at energies to 10 keV. 6 refs., 10 figs., 2 tabs.
Date: June 30, 1989
Creator: Schlachter, A.S.
System: The UNT Digital Library
Configuration and layout of the tandem mirror Fusion Power Demonstrator (open access)

Configuration and layout of the tandem mirror Fusion Power Demonstrator

Studies have been performed during the past year to determine the configuration of a tandem mirror Fusion Power Demonstrator (FPD) machine capable of producing 1750 MW of fusion power. The FPD is seen as the next logical step after the Mirror Fusion Test Facility-B (MFTF-B) toward operation of a power reactor. The design of the FPD machine allows a phased construction: Phase I, a hydrogen or deuterium checkout machine; Phase 2, a DT breakeven machine; Phase 3, development of the Phase 2 machine to provide net power and act as a reactor demonstrator. These phases are essential to the development of remote handling equipment and the design of components that will ultimately be remotely handled. Phasing also permits more modes funding early in the program with some costs committed only after reaching major milestones.
Date: November 30, 1983
Creator: Clarkson, I.R. & Neef, W.S.
System: The UNT Digital Library
Assurance management program for the 30 Nova laser fusion project (open access)

Assurance management program for the 30 Nova laser fusion project

The Nova assurance management program was developed using the quality assurance (QA) approach first implemented at LLNL in early 1978. The LLNL QA program is described as an introduction to the Nova assurance management program. The Nova system is described pictorially through the Nova configuration, subsystems and major components, interjecting the QA techniques which are being pragmatically used to assure the successful completion of the project.
Date: November 30, 1983
Creator: Levy, A.J.
System: The UNT Digital Library
TF-ripple loss of suprathermal alphas in ITER (open access)

TF-ripple loss of suprathermal alphas in ITER

TF-ripple loss of alphas below the critical energy is calculated for a noncircular ITER plasma. For 14 toroidal field (TF) coils, the particle loss was found to be about 6%. About 0.6% of the initial alpha energy (3.5 MeV) is lost. 26 refs., 9 figs., 3 tabs.
Date: September 30, 1989
Creator: unknown
System: The UNT Digital Library
Calculated late time spectra of supernovae (open access)

Calculated late time spectra of supernovae

We consider here the nebular phase spectra of supernovae whose late time luminosity is provided by the radioactive decay of /sup 56/Ni and /sup 56/Co synthesized in the explosion. A broad variety of supernovae are known or suspected to fall in this category. This includes all SNIa and SNIb, and at least some SNII, in particular SN1987a. At sufficiently late times the expanding supernova becomes basically nebular in character due to its decreasing optical depth. The spectra produced during this stage contain information on the density and abundance structure of the entire supernova, as opposed to spectra near maximum light which are affected only by the outermost layers. A numerical model for nebular spectrum formation is therefore potentially very valuable for answering currently outstanding questions about the post-explosion supernova structure. As an example, we can hope to determine the degree of mixing which occurs between the layers of the ''onion-skin'' abundance structure predicted by current one dimensional explosion calculations. In the sections which follow, such a numerical model is briefly described and then applied to SN1972e, a typical SNIa, SN1985f, an SNIb, and finally to SN1987a. In the case of SN1987a predicted spectra are presented for the wavelength range from …
Date: October 30, 1987
Creator: Axelrod, T.S.
System: The UNT Digital Library
Theory of optical flashes (open access)

Theory of optical flashes

The theory of optical flashes created by x- and ..gamma..-ray burst heating of stars in binaries is reviewed. Calculations of spectra due to steady-state x-ray reprocessing and estimates of the fundamental time scales for the non-steady case are discussed. The results are applied to the extant optical data from x-ray and ..gamma..-ray bursters. Finally, I review predictions of flashes from ..gamma..-ray bursters detectable by a state of the art all-sky optical monitor.
Date: September 30, 1983
Creator: London, R. A.
System: The UNT Digital Library
Design, placement, and sampling of groundwater monitoring wells for the management of hazardous waste disposal facilities (open access)

Design, placement, and sampling of groundwater monitoring wells for the management of hazardous waste disposal facilities

Groundwater monitoring is an important technical requirement in managing hazardous waste disposal facilities. The purpose of monitoring is to assess whether and how a disposal facility is affecting the underlying groundwater system. This paper focuses on the regulatory and technical aspects of the design, placement, and sampling of groundwater monitoring wells for hazardous waste disposal facilities. Such facilities include surface impoundments, landfills, waste piles, and land treatment facilities. 8 refs., 4 figs.
Date: September 30, 1988
Creator: Tsai, S.Y.
System: The UNT Digital Library
Charmonium spectroscopy, 1987 (open access)

Charmonium spectroscopy, 1987

The state of charmonium spectroscopy is reviewed. All analyses proceed from a spin-dependent, non-relativistic Schroedinger equation. Many of the possible branching ratios for charm like states are investigated. 17 refs.
Date: July 30, 1987
Creator: Cahn, R.N.
System: The UNT Digital Library