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Impulsive ion acceleration in earth's outer magnetosphere (open access)

Impulsive ion acceleration in earth's outer magnetosphere

Considerable observational evidence is found that ions are accelerated to high energies in the outer magnetosphere during geomagnetic disturbances. The acceleration often appears to be quite impulsive causing temporally brief (10's of seconds), very intense bursts of ions in the distant plasma sheet as well as in the near-tail region. These ion bursts extend in energy from 10's of keV to over 1 MeV and are closely associated with substorm expansive phase onsets. Although the very energetic ions are not of dominant importance for magnetotail plasma dynamics, they serve as an important tracer population. Their absolute intensity and brief temporal appearance bespeaks a strong and rapid acceleration process in the near-tail, very probably involving large induced electric fields substantially greater than those associated with cross-tail potential drops. Subsequent to their impulsive acceleration, these ions are injected into the outer trapping regions forming ion ''drift echo'' events, as well as streaming tailward away from their acceleration site in the near-earth plasma sheet. Most auroral ion acceleration processes occur (or are greatly enhanced) during the time that these global magnetospheric events are occurring in the magnetotail. A qualitative model relating energetic ion populations to near-tail magnetic reconnection at substorm onset followed by …
Date: January 1, 1985
Creator: Baker, D.N. & Belian, R.D.
System: The UNT Digital Library
Decontamination of Savannah River Plant H-Area hot-canyon crane (open access)

Decontamination of Savannah River Plant H-Area hot-canyon crane

Decontamination techniques applicable to the remotely operated bridge cranes in canyon buildings at the Savannah River Plant (SRP) were identified and were evaluated in laboratory-scale tests. High pressure Freon blasting was found to be the most attractive process available for this application. Strippable coatings were selected as an alternative technique in selected applications. The ability of high pressure Freon blasting plus two strippable coatings (Quadcoat 100 and Alara 1146) to remove the type of contamination expected on SRP cranes was demonstrated in laboratory-scale tests. Quadrex HPS was given a contract to decontaminate the H-Area hot canyon crane. Decontamination operations were successfully carried out within the specified time-frame window. The radiation level goals specified by SRP were met and decontamination was accomplished with 85% less personnel exposure than estimated by SRP before the job started. This reduction is attributed to the increased efficiency of the new decontamination techniques used. 6 refs., 1 tab.
Date: January 1, 1985
Creator: Rankin, W N & Sims, J R
System: The UNT Digital Library
Relation between finite element methods and nodal methods in transport theory (open access)

Relation between finite element methods and nodal methods in transport theory

This paper examines the relationship between nodal methods and finite-element methods for solving the discrete-ordinates form of the transport equation in x-y geometry. Specifically, we will examine the relation of three finite-element schemes to the linear-linear (LL) and linear-nodal (LN) nodal schemes. The three finite-element schemes are the linear-continuous-diamond-difference (DD) scheme, the linear-discontinuous (LD) scheme, and the quadratic-discontinuous (QD) scheme. A brief derivation of the (LL) and (LN) nodal schemes is given in the third section of this paper. The approximations that cause the LL scheme to reduce to the DD, LD, and QD schemes are then indicated. An extremely simple method of deriving the finite-element schemes is then introduced.
Date: January 1, 1985
Creator: Walters, W. F.
System: The UNT Digital Library
Fueling of tandem mirror reactors (open access)

Fueling of tandem mirror reactors

This paper summarizes the fueling requirements for experimental and demonstration tandem mirror reactors (TMRs), reviews the status of conventional pellet injectors, and identifies some candidate accelerators that may be needed for fueling tandem mirror reactors. Characteristics and limitations of three types of accelerators are described; neutral beam injectors, electromagnetic rail guns, and laser beam drivers. Based on these characteristics and limitations, a computer module was developed for the Tandem Mirror Reactor Systems Code (TMRSC) to select the pellet injector/accelerator combination which most nearly satisfies the fueling requirements for a given machine design.
Date: January 1, 1985
Creator: Gorker, G. E. & Logan, B. G.
System: The UNT Digital Library
Potential energy for quarks (open access)

Potential energy for quarks

It is argued on theoretical and phenomenological grounds that confinement of quarks is intrinsically a many-body interaction. The Born-Oppenheimer approximation to the bag model is shown to give rise to a static potential energy that consists of a sum of two-body Coulomb terms and a many-body confining term. Following the success of this potential in heavy Q anti Q systems it is being applied to Q/sup 2/ anti Q/sup 2/. Preliminary calculations suggest that dimeson bound states with exotic flavor, such as bb anti s anti s, exist. 13 refs., 5 figs.
Date: January 1, 1985
Creator: Heller, L.
System: The UNT Digital Library
Source-jerk analysis using a semi-explicit inverse kinetic technique (open access)

Source-jerk analysis using a semi-explicit inverse kinetic technique

A method is proposed for measuring the effective reproduction factor, k, in subcritical systems. The method uses the transient response of a subcritical system to the sudden removal of an extraneous neutron source (i.e., a source jerk). The response is analyzed using an inverse kinetic technique that least-squares fits the exact analytical solution corresponding to a source-jerk transient as derived from the point-reactor model. It has been found that the technique can provide an accurate means of measuring k in systems that are close to critical (i.e., 0.95 < k < 1.0). As a system becomes more subcritical (i.e., k << 1.0) spatial effects can introduce significant biases depending on the source and detector positions. However, methods are available that can correct for these biases and, hence, can allow measuring subcriticality in systems with k as low as 0.5. 12 refs., 3 figs.
Date: January 1, 1985
Creator: Spriggs, G.D. & Pederson, R.A.
System: The UNT Digital Library
Magma energy and geothermal permeability enhancement programs (open access)

Magma energy and geothermal permeability enhancement programs

Accomplishments during FY85 and project plans for FY86 are described for the Magma Energy Extraction and Permeability Enhancement programs. (ACR)
Date: January 1, 1985
Creator: Dunn, J.C.
System: The UNT Digital Library
Electron-beam envelopes and matching for a combined wiggler and alternating-gradient quadrupole channel (open access)

Electron-beam envelopes and matching for a combined wiggler and alternating-gradient quadrupole channel

This work studies the electron-beam envelopes and matching for a combined wiggler and alternating-gradient quadrupole field for a free-electron laser (FEL) that will be operated in the VUV or XUV wavelength region. The quadrupole field is assumed to vary continuously along the symmetry axis. The linearized equations of electron motion are solved analytically by using the two-scale perturbation method for a plane polarized wiggler. The electron-beam envelopes and the envelope equations, as well as the matching conditions in phase space, are obtained from the electron trajectories. A comparison with the numerical solution is presented.
Date: January 1, 1985
Creator: Wang, T. F. & Cooper, R. K.
System: The UNT Digital Library
Radiation dosimetry through spectral definition (open access)

Radiation dosimetry through spectral definition

We have developed a fieldable instrumentation system for determining from measured flux spectra, both the neutron and gamma ray dose rate distributions associated with radioactive sources. This system includes the sensors, the computer-based data acquisition and analysis hardware, and the requisite software for unfolding the sensor response functions to obtain the flux spectra, and for folding the resultant flux spectra with appropriate flux spectrum-to-dose conversion factors. We use bismuth germanate scintillators that have experimentally measured and analytically interpolated response functions to determine the gamma ray flux spectra, and a suite of neutron sensors, based on proton recoil and /sup 3/He capture, to determine the neutron flux spectra. In addition, gamma ray peak identification is done using HPGe sensors. We describe the equipment and procedures and present some recent results. 10 refs., 15 figs.
Date: January 1, 1985
Creator: Dowdy, E. J.; Moss, C. E.; Robba, A. A.; Evans, A. E.; Lucas, M. C.; Shunk, E. R. et al.
System: The UNT Digital Library
Neutron scattering from solutions: the hydration of lanthanide and actinide ions (open access)

Neutron scattering from solutions: the hydration of lanthanide and actinide ions

The neutron scattering difference method is described and applied to investigations of the aqua rare-earth ions, Nd/sup 3 +/ and Dy/sup 3 +/. Metal-water distances and hydration numbers have been unambiguously determined for these ions' inner coordination spheres. The values of the hydration number, n, of 8.5 +- 0.2 for Nd/sup 3 +/ and 7.4 +- 0.5 for Dy/sup 3 +/, directly support the claim of Spedding et al. that n decreases by one unit across the lanthanide series. The possible application of this method to actinide ions in solution is also discussed. 7 refs., 4 figs.
Date: January 1, 1985
Creator: Hahn, R.L.; Narten, A.H. & Annis, B.K.
System: The UNT Digital Library
Status of the translawrencium elements (Z > 103) (open access)

Status of the translawrencium elements (Z > 103)

As a result of conflicting claims to the discovery of the trans-lawrencium elements (Z > 103), IUPAC's Inorganic Chemistry Nomenclature Commission, (II.2), has been incapable of coming to a decision on rightful discoverer for these elements. In addition, the Atomic Weights Commission, (II.1), has from time to time been interested in the status of the search for the superheavy elements, i.e., those elements which might be found in the vicinity of the 'island of stability'. Theoretical studies have indicated that the next major shell closures beyond Z = 82 and N = 126 would occur at Z = 114 and N = 184. In recent years, many scientists have devoted their time and effort in an attempt to detect these superheavy elements. This paper will review the literature on both of these developments and provide an up-to-date status report for the use of the Commission. However, this paper will not address the pros and cons of the controversial systematic naming scheme proposed by the Nomenclature Commission, (II.2) and approved by IUPAC. 56 refs.
Date: January 1, 1985
Creator: Holden, Norman E.
System: The UNT Digital Library
Long-lived heavy mass elements half-lives (A > 125) (open access)

Long-lived heavy mass elements half-lives (A > 125)

Reported values of half-lives of intermediate mass and heavy elements are evaluated. The evaluation analysis estimates the systematic error the resulting standard deviation. Recommended values are then presented for /sup 128/Te, /sup 130/Te, /sup 129/I, /sup 138/La, /sup 144/Nd, /sup 145/Nd, /sup 146,147,148/Sm, /sup 152/Gd, /sup 154/Dy, /sup 176/Lu, /sup 174/Hf, /sup 180/Ta, /sup 187/Re, /sup 186/Os, /sup 190/Pt, /sup 204,205/Pb, and /sup 230,232/Th. 103 refs., 21 tabs. (WRF)
Date: January 1, 1985
Creator: Holden, Norman E.
System: The UNT Digital Library
Role of groundwater oxidation potential and radiolysis on waste glass performance in crystalline repository environments (open access)

Role of groundwater oxidation potential and radiolysis on waste glass performance in crystalline repository environments

Laboratory experiments have shown that groundwater conditions in a Stripa granite repository will be as reducing as those in a basalt repository. The final oxidation potential (Eh) at 70/sup 0/C for Stripa groundwater deaerated and equilibrated with crystalline granite was -0.45V. In contrast, the oxidation potential at 60/sup 0/C for Grande Ronde groundwater equilibrated with basalt was -0.40V. The reducing groundwater conditions were found to slightly decrease the time-dependent release of soluble components from the waste glass. Spectrophotometric analysis of the equilibrated groundwaters indicated the presence of Fe/sup 2 +/ confirming that the Fe/sup 2 +//Fe/sup 3 +/ couple is controlling the oxidation potential. It was also shown that in the alkaline pH regime of these groundwaters the iron species are primarily associated with x-ray amorphous precipitates in the groundwater. Gamma radiolysis in the absence of waste glass and in the absence of oxygen further reduces the oxidation potential of both granitic and basaltic groundwaters. The effect is more pronounced in the basaltic groundwater. The mechanism for this decrease is under investigation but appears related to the reactive amorphous precipitate. The results of these tests suggest that H/sub 2/ may not escape from the repository system as postulated and that …
Date: January 1, 1985
Creator: Jantzen, Carol M. & Bibler, Ned E.
System: The UNT Digital Library
Distortion of He emission lines after fast-ion collisions (open access)

Distortion of He emission lines after fast-ion collisions

After excitation by fast ions (velocity = 2 to 5 au) the emission line profiles of doubly-excited helium atoms are observed to differ significantly from the normal shape of Beutler-Fano resonances. This difference is attributed to the Coulomb interaction between the emitted electron and the ion used to excite the atom. We explain the effect quantitatively with a simple classical model combined with a post-collision-interaction theory. 4 refs., 4 figs.
Date: January 1, 1985
Creator: Arcuni, P. W.
System: The UNT Digital Library
Noninterceptive beam diagnostics (open access)

Noninterceptive beam diagnostics

The need for accurate real-time diagnostics is critical for high-power particle beams. This paper describes the present level of development of noninterceptive devices for these beams. Discussion will be related to diagnostic measurements as they occur along the beamline, from ion-source performance through presentation to an RFQ and measures of the RFQ output, using the cw beam at Los Alamos as a guide. 23 refs.
Date: January 1, 1985
Creator: Chamberlin, D.D.
System: The UNT Digital Library
Leaching studies of low-level radioactive waste forms (open access)

Leaching studies of low-level radioactive waste forms

A research program has been under way at the Brookhaven National Laboratory to investigate the radionuclide release behavior of ion exchange bead resin waste solidified in Portland cement. An important aspect of this program is to develop and evaluate testing procedures and methodologies which enable the long-term performance evaluation of waste forms under simulated field conditions. Cesium and strontium release behavior using a range of testing procedures, including intermittent leachant flow conditions, has been investigated. For cyclic wet/dry leaching tests, extended dry periods tend to enhance the release of Cs and suppress the release of Sr. Under extended wet period leaching conditions, however, both Cs and Sr exhibit suppressed releases. In contrast, radionuclide releases observed under continuously saturated leaching conditions, as represented by conventional leaching tests, are significantly different. The relevance and aplicability of these laboratory data obtained under a wide range of leaching conditions to the performance evaluation of waste forms under anticipated field conditions is discussed. 12 refs., 9 figs., 3 tabs.
Date: January 1, 1985
Creator: Dayal, R.; Arora, H.; Clinton, J.C. & Milian, L.
System: The UNT Digital Library
Experiments on eta-meson production (open access)

Experiments on eta-meson production

Following a review of some highlights of eta-meson characteristics, the status of eta-meson production experiments is reviewed. The physics motivations and first results of two LAMPF experiments on (..pi..,eta) reactions are discussed. Possible future experiments are also discussed. 42 refs., 12 figs., 4 tabs.
Date: January 1, 1985
Creator: Peng, J.C.
System: The UNT Digital Library
Charge exchange processes involving iron ions (open access)

Charge exchange processes involving iron ions

A review and evaluation is given of the experimental data which are available for charge exchange processes involving iron ions and neutral H, H/sub 2/ and He. Appropriate scaling laws are presented, and their accuracy estimated for these systems. A bibliography is given of available data sources, as well as of useful data compilations and review articles. A procedure is recommended for providing single approximate formulae to the fusion community to describe total cross sections for electron capture by partially-stripped Fe/sup q+/ ions in collisions with H, H/sub 2/ and He, based on the scaling relationships suggested by Janev and Hvelplund.
Date: January 1, 1985
Creator: Phaneuf, R.A.
System: The UNT Digital Library
Liquid helium dump concept for a large scale superconducting magnetic energy storage plant (open access)

Liquid helium dump concept for a large scale superconducting magnetic energy storage plant

Superconducting Magnetic Energy Storage (SMES) is a potentially cost effective technology for electric utility load leveling. Design concepts and cost estimates of SMES plants capable of delivering 5000 MWh daily have been previously identified. An important feature of a large commercial plant is a system that will reliably shut down the magnet by thermally dissipating the stored energy in the event of an imminent or actual loss of superconductivity. To prevent damage to the coil during such a protective energy dump, the entire coil must be driven ''normal'', i.e., resistive rather than superconducting, in a short period of time. This requires rapid removal of the liquid helium coolant surrounding the coil. This paper describes a simple system that has been developed to rapidly remove the liquid helium from the helium vessel. The system requires only a small number of active components, no external helium storage, and is practical to reset and maintain.
Date: January 1, 1985
Creator: Schoenung, S. M.; Loyd, R. J.; Nakamura, T.; Rogers, J. D. & Purcell, J. R.
System: The UNT Digital Library
Robotic sample preparation for radiochemical plutonium and americium analyses (open access)

Robotic sample preparation for radiochemical plutonium and americium analyses

A Zymate robotic system has been assembled and programmed to prepare samples for plutonium and americium analyses by radioactivity counting. The system performs two procedures: a simple dilution procedure and a TTA (xylene) extraction of plutonium. To perform the procedures, the robotic system executes 11 unit operations such as weighing, pipetting, mixing, etc. Approximately 150 programs, which require 64 kilobytes of memory, control the system. The system is now being tested with high-purity plutonium metal and plutonium oxide samples. Our studies indicate that the system can give results that agree within 5% at the 95% confidence level with determinations performed manually. 1 ref., 1 fig., 1 tab.
Date: January 1, 1985
Creator: Stalnaker, N.; Beugelsdijk, T.; Thurston, A. & Quintana, J.
System: The UNT Digital Library
Expert systems for design and simulation (open access)

Expert systems for design and simulation

We discuss work in progress on two expert systems. We are developing systems that use artificial intelligence techniques to simplify the use of large simulation codes and to help design complicated physical devices. The simulation codes are used in analyzing and designing weapons, and the devices are themselves part of weapon systems. But we focus not only on the particular applications, but also on the broader issues common to design problems: large solution spaces and tentative reasoning. We also discuss some practical difficulties encountered during the project. One expert system provides an interface between users and several simulation codes. It checks input for errors, builds input files for the codes, and submits jobs to a central computing facility. The other expert system helps turn a description of a device into a particular design. Currently this expert system includes three major parts: a translator of descriptions into designs, a graphics interface that presents the design to the user and allows him to manipulate it, and a refiner of designs. The latter is the ''smartest'' part of the system, and the target of much of our present efforts.
Date: January 1, 1985
Creator: Aldridge, J.; Cerutti, J.; Draisin, W. & Steuerwalt, M.
System: The UNT Digital Library
Study of quark fragmentation in e/sup +/e/sup -/ annihilation at 29 GeV: charged particle multiplicity distributions (open access)

Study of quark fragmentation in e/sup +/e/sup -/ annihilation at 29 GeV: charged particle multiplicity distributions

This paper presents the charged particle multiplicity distributions for e/sup +/e/sup -/ annihilation at ..sqrt..s = 29 GeV measured in the High Resolution Spectrometer. The data, which correspond to an integrated luminosity of 185 pb/sup -1/, were obtained at the e/sup +/e/sup -/ storage ring PEP. The techniques used to obtain the original distributions from the observed prong numbers are discussed. The multiplicity distribution of the charged particles with a two jet selection has a mean value <Nch> = 13.02 +- 0.03 +- 0.5; and a dispersion D = 3.84 +- 0.02 +- 0.1. The mean multiplicity increases with the event sphericity. No correlation is observed between the multiplicities in the two jets that characterize most of the events. For the single jets a value of D = 2.71 +- 0.02 +- 0.06 is measured which gives further support the idea of independent jet fragmentation. When compared with e/sup +/e/sup -/ data at other energies, the multiplicity distributions exhibit the scaling behavior in the mean first suggested by Koba, Nielsen and Olsen (KNO). The KNO distribution in the central rapidity interval is broader than that for the whole rapidity span and agrees well with the generalized Bose-Einstein formula for three …
Date: January 1, 1985
Creator: Derrick, M.; Kooijman, P.; Loos, J.S.; Musgrave, B.; Price, L.E.; Schlereth, J. et al.
System: The UNT Digital Library
Table of radioactive elements (open access)

Table of radioactive elements

As has been the custom in the past, the Commission publishes a table of relative atomic masses and halflives of selected radionuclides. The information contained in this table will enable the user to calculate the atomic weight for radioactive materials with a variety of isotopic compositions. The atomic masses have been taken from the 1984 Atomic Mass Table. Some of the halflives have already been documented.
Date: January 1, 1985
Creator: Holden, Norman E.
System: The UNT Digital Library
Combined electrochemical/surface science investigations of Pt/Cr alloy electrodes (open access)

Combined electrochemical/surface science investigations of Pt/Cr alloy electrodes

Chromium addition improves the performance of carbon-supported Pt electrodes for oxygen reduction in phosphoric acid fuel cells. To clarify the role of chromium and its chemical nature at the electrode surface, we have performed a combined electrochemical/surface science investigation of a series of bulk Pt/sub x/Cr/sub (1-x)/ alloys (0 less than or equal to x less than or equal to 1). In this paper we report the surface characterization of the starting electrodes by XPS, electrochemical results from cyclic voltammetry in 85% phosphoric acid, and post-electrochemical surface characterization. For Cr contents less than 40%, the electrodes were quite stable up to +1.6 V vs DHE. The surface Cr was largely oxidized to Cr/sup +3/ for surfaces at open circuit ad those exposed at potentials < +1.4 V. For intermediate Cr levels, Cr was leached from the surface region by +1.5 V, leaving a porous Pt electrode with increased electrochemical hydrogen adsorption capacity. For Pt/sub 0.2//Cr/sub 0.8/, treatments at +1.4 V and above led to the appearance of Pt/sup 4 +/ and Cr/sup 6 +/ species, apparently stabilized in a porous phosphate overlayer up to 50 A thick. The Pt electrochemical hydrogen adsorption capacity was simultaneously increased by a factor of …
Date: January 1, 1985
Creator: Daube, K. A.; Paffett, M. T.; Gottesfeld, S. & Campbell, C. T.
System: The UNT Digital Library