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Evaluation of LLNL-ALICE code contribution (open access)

Evaluation of LLNL-ALICE code contribution

We summarize some of the areas of comparison with experimental data for which the ALICE code did poorly. We suggest some aspects which might be improved in the future. A crude accuracy factor is estimated as a predictive reliability based on the intercomparison exercise.
Date: March 24, 1994
Creator: Blann, M.
System: The UNT Digital Library
Kinetic effects near the magnetopause (open access)

Kinetic effects near the magnetopause

Boundary conditions for magnetopause processes such as reconnection can be understood by studying the properties of magnetosheath plasma as it flows toward this transition. This manuscript reviews the role of electromagnetic ion cyclotron instabilities in constraining ion temperature anisotropies in the magnetosheath. Linear Vlasov theory and hybrid computer simulations have demonstrated that the inverse correlation between the proton anisotropy and the parallel proton {beta} observed from AMPTE/CCE in the subsolar sheath is due to wave-particle scattering by ion cyclotron anisotropy instabilities. Recent research on this topic is reviewed and the application of this inverse correlation to a successful bounded anisotropy model of proton temperatures in the sheath is described.
Date: March 24, 1994
Creator: Gary, S. P.; Winske, D.; McKean, M. E.; Fuselier, S. A.; Denton, R. E. & Anderson, B. J.
System: The UNT Digital Library
Model-based ocean acoustic passive localization (open access)

Model-based ocean acoustic passive localization

The detection, localization and classification of acoustic sources (targets) in a hostile ocean environment is a difficult problem -- especially in light of the improved design of modern submarines and the continual improvement in quieting technology. Further the advent of more and more diesel-powered vessels makes the detection problem even more formidable than ever before. It has recently been recognized that the incorporation of a mathematical model that accurately represents the phenomenology under investigation can vastly improve the performance of any processor, assuming, of course, that the model is accurate. Therefore, it is necessary to incorporate more knowledge about the ocean environment into detection and localization algorithms in order to enhance the overall signal-to-noise ratios and improve performance. An alternative methodology to matched-field/matched-mode processing is the so-called model-based processor which is based on a state-space representation of the normal-mode propagation model. If state-space solutions can be accomplished, then many of the current ocean acoustic processing problems can be analyzed and solved using this framework to analyze performance results based on firm statistical and system theoretic grounds. The model-based approach, is (simply) ``incorporating mathematical models of both physical phenomenology and the measurement processes including noise into the processor to extract the …
Date: January 24, 1994
Creator: Candy, J. V. & Sullivan, E. J.
System: The UNT Digital Library
Numerical modeling of a small recirculating induction accelerator for heavy-ion fusion (open access)

Numerical modeling of a small recirculating induction accelerator for heavy-ion fusion

A series of small-scale experiments has been proposed to study critical physics issues of a circular induction accelerator for heavy-ion fusion. Because the beam dynamics will be dominated by space charge, the experiments require careful design of the lattice and acceleration schedule. A hierarchy of codes has been developed for modeling the experiments at different levels of detail. The codes are discussed briefly, and examples of the output are presented.
Date: June 24, 1994
Creator: Sharp, W. M.; Barnard, J. J.; Friedman, A.; Grote, D. P.; Lund, S. M.; Newton, M. A. et al.
System: The UNT Digital Library
Relationships of radon diffusion coefficient with saturated hydraulic conductivity, fines content and moisture saturation of radon/infiltration barriers for the UMTRA Project (open access)

Relationships of radon diffusion coefficient with saturated hydraulic conductivity, fines content and moisture saturation of radon/infiltration barriers for the UMTRA Project

The release of {sup 222}Radon to the atmosphere is controlled by the rate of its gas transport through earthen materials. Of the many soil-related parameters, radon diffusion coefficient is the key parameter that characterizes this transport. We compared the radon diffusion coefficients measured at the laboratories for the UMTRA Project with simple empirical correlations developed by others. The empirical correlations predict the radon diffusion coefficient based on the fraction of moisture saturation and porosity. One of the more recent correlations agrees reasonably well with the measurements. In addition, by using a series of correlation curves, we studied the empirical relationships of the. radon diffusion coefficient with the saturated hydraulic conductivity, the fines content, and the moisture saturation in soil. The results reveal that a reliable determination of the long-term moisture and porosity is essential in the design of an adequate radon barrier with respect to the radon diffusion coefficient.
Date: January 24, 1994
Creator: Li, P. Y. & Chen, P. K.
System: The UNT Digital Library
Intercomparison of codes for intermediate energy nuclear data: The first step (open access)

Intercomparison of codes for intermediate energy nuclear data: The first step

Several weak points of the intermediate energy nuclear data calculated in this exercise are described as introduction to some of the areas needing discussion at this meeting. These include nuclear structure effects on precompound spectra, large variations between codes in predicted total reaction cross sections, and in total neutron and proton multiplicities. INC codes don`t reflect correct experimental Q values, and may have difficulties at very low angles due to overestimation of the quasi-elastic peak. We raise questions as to additional reaction properties (beyond n and p spectra) which may need benchmarking.
Date: March 24, 1994
Creator: Blann, M.; Gruppelaar, H.; Nagel, P. & Rodens, J.
System: The UNT Digital Library
Determination of operating limits for radionuclides for a proposed landfill at Paducah Gaseous Diffusion Plant (open access)

Determination of operating limits for radionuclides for a proposed landfill at Paducah Gaseous Diffusion Plant

The operating limits for radionuclides in sanitary and industrial wastes were determined for a proposed landfill at the Paducah Gaseous Diffusion Plant (PGDP), Kentucky. These limits, which may be very small but nonzero, are not mandated by law or regulation but are needed for rational operation. The approach was based on analyses of the potential contamination of groundwater at the plant boundary and the potential exposure to radioactivity of an intruder at the landfill after closure. The groundwater analysis includes (1) a source model describing the disposal of waste and the release of radionuclides from waste to the groundwater, (2) site-specific groundwater flow and contaminant transport calculations, and (3) calculations of operating limits from the dose limit and conversion factors. The intruder analysis includes pathways through ingestion of contaminated vegetables and soil, external exposure to contaminated soil, and inhalation of suspended activity from contaminated soil particles. In both analyses, a limit on annual effective dose equivalent of 4 mrem (0.04 mSv) was adopted. The intended application of the results is to refine the radiological monitoring standards employed by the PGDP Health Physics personnel to determine what constitutes radioactive wastes, with concurrence of the Commonwealth of Kentucky.
Date: May 24, 1994
Creator: Wang, J. C.; Lee, D. W.; Ketelle, R. H.; Lee, R. R. & Kocher, D. C.
System: The UNT Digital Library
Pollution prevention opportunity assessment: Foundation of pollution prevention for waste management (open access)

Pollution prevention opportunity assessment: Foundation of pollution prevention for waste management

The objective of this paper is to promote the Pollution Prevention Opportunity Assessment (PPOA) technique as a fundamental of pollution prevention for waste management. All key elements of an effective PPOA program are presented. These key elements include impacts of environmental laws on pollution prevention, PPOA concepts and overview, waste minimization opportunities assessment, reporting and monitoring waste minimization progress, and PPOA program implementation. As environmental laws evolve the focus is shifting from end-of-pipe pollution control to front-end source reduction. Waste minimization was mistakenly interpreted to mean the reduction of hazardous waste after generation in the past. The Pollution Prevention Act of 1990 has clearly defined its requirement on resource reduction. Waste reduction can be viewed as a criterion to assess all industrial processes and operations. The fundamental approach of PPOA focuses on a mass balance concept. This concept deals with tracking of chemicals from the point of purchase, through storage, utilization in the process, and waste generation at the end of process. In other words, PPOA is a technique to analyze this input/output process. By applying PPOA techniques, the framework of applicable compliance requirements to the current operation process is established. Furthermore, documentation of PPOA itself can meet as documentation …
Date: March 24, 1994
Creator: Damewood, R. W.
System: The UNT Digital Library
Selective Fluorescence Quenching to Discriminate Between Alternant and Non-alternant Polycyclic Aromatic Hydrocarbons: Acephenanthrylene Derivatives as Exceptions to the Nitromethane Quenching Rule (open access)

Selective Fluorescence Quenching to Discriminate Between Alternant and Non-alternant Polycyclic Aromatic Hydrocarbons: Acephenanthrylene Derivatives as Exceptions to the Nitromethane Quenching Rule

Article on selective fluorescence quenching to discriminate between alternant and non-alternant polycyclic aromatic hydrocarbons and acephenanthrylene derivatives as exceptions to the nitromethane quenching rule.
Date: February 24, 1994
Creator: Tucker, Sheryl A. (Sheryl Ann); Griffin, Jason M.; Acree, William E. (William Eugene); Mulder, Patrick P. J.; Lugtenburg, Johan & Cornelisse, Jan
System: The UNT Digital Library
A 10 GHz BANDWIDTH, SINGLE TRANSIENT, DIGITIZED OSCILLOSCOPE WITH 20 GHz CAPABILITY (open access)

A 10 GHz BANDWIDTH, SINGLE TRANSIENT, DIGITIZED OSCILLOSCOPE WITH 20 GHz CAPABILITY

EG&G/EM has developed an oscilloscope with a {minus}3 dB bandwidth greater than 10 GHz. Its rolloff characteristics are such that single-transient data greater than 20 GHz may be captured. A demountable CCD camera records the oscilloscope trace and is provided with PC-compatible capture and data processing software. The capabilities of the oscilloscope, camera, and its processing software are described and examples of the system`s performance is shown.
Date: January 24, 1994
Creator: Hudson, C. L.; Kocimski, S. M.; Spector, J.; Thomas, J. B. & Woodstra, R. R.
System: The UNT Digital Library
Heating and current drive systems for TPX (open access)

Heating and current drive systems for TPX

The heating and current drive (H and CD) system proposed for the TPX tokamak will consist of ion cyclotron, neutral beam, and lower hybrid systems. It will have 17.5 MW of installed H and CD power initially, and can be upgraded to 45 MW. It will be used to explore advanced confinement and fully current-driven plasma regimes with pulse lengths of up to 1,000 s.
Date: May 24, 1994
Creator: Swain, D.; Goranson, P.; Halle, A. von; Bernabei, S. & Greenough, N.
System: The UNT Digital Library
Magnetic excitations in a random exchange system Fe{sub x}Mn{sub 1-x}TiO{sub 3} (open access)

Magnetic excitations in a random exchange system Fe{sub x}Mn{sub 1-x}TiO{sub 3}

In order to examine the influence of exchange frustration on spin wave excitations, inelastic neutron scattering experiments have been performed on a random exchange system Fe{sub x}Mn{sub l-x}TiO{sub 3} with x = 0.00, 0.10, 0.25 and 0.33. For all three mixed systems, the magnetic excitation spectra consist of two components: a well-defined spin wave component and a broad damped component. The latter can be well fitted to a spectral weight function for a damped harmonic oscillator.
Date: August 24, 1994
Creator: Kawano, H.; Yoshizawa, H.; Nicklow, R. M. & Ito, A.
System: The UNT Digital Library