Systematic effects in CALOR simulation code to model experimental configurations (open access)

Systematic effects in CALOR simulation code to model experimental configurations

CALOR89 code system is being used to simulate test beam results and the design parameters of several calorimeter configurations. It has been bench-marked against the ZEUS, D{theta} and HELIOS data. This study identifies the systematic effects in CALOR simulation to model the experimental configurations. Five major systematic effects are identified. These are the choice of high energy nuclear collision model, material composition, scintillator saturation, shower integration time, and the shower containment. Quantitative estimates of these systematic effects are presented. 23 refs., 6 figs., 7 tabs.
Date: March 27, 1991
Creator: Job, P.K.; Proudfoot, J. (Argonne National Lab., IL (USA)); Handler, T. (Tennessee Univ., Knoxville, TN (USA). Dept. of Physics and Astronomy) & Gabriel, T.A. (Oak Ridge National Lab., TN (USA))
System: The UNT Digital Library
UNT to work with six Metroplex elementary schools in national arts experiment designed to boost achievement (open access)

UNT to work with six Metroplex elementary schools in national arts experiment designed to boost achievement

An information release document in regards to six metroplex elementary schools plus thirty other schools nationwide were selected to participate as Arts Partner Schools in a $15 million experiment to reform education. The six schools will work with art educators at the University of North Texas, announced this month by the Annenberg Foundation, the Getty Education Institute for the Arts and the National Arts Education Consortium.
Date: March 27, 1997
Creator: LeMay, Nancy C.
System: The UNT Digital Library
Energetic charged particle beams for disablement of mines (open access)

Energetic charged particle beams for disablement of mines

LLNL has an ongoing program of weapons disablement using energetic charged particle beams; this program combines theoretical and experimental expertise in accelerators, high-energy and nuclear physics, plasma physics and hydrodynamics to simulate/measure effects of electron and proton beams on weapons. This paper reviews work by LLNL, LANL and NSWC on detonating sensitive and insensitive high explosives and land mines using high-current electron beams. Computer simulations are given. 20--160 MeV electron beams incident on wet/dry soils are being studied, along with electron beam propagation in air. Compact high current, high energy accelerators are being developed for mine clearing. Countermine missions of interest are discussed. 25 refs., 9 figs.
Date: March 27, 1995
Creator: Wuest, C.R.
System: The UNT Digital Library
Efficient computation of periodic and nonperiodic Green`s functions in layered media using the MPIE (open access)

Efficient computation of periodic and nonperiodic Green`s functions in layered media using the MPIE

The mixed potential integral equation (MPIE) formulation is convenient for problems involving layered media because potential quantities involve low order singularities, in comparison to field quantities. For nonperiodic problems, the associated Green`s potentials involve spectral integrals of the Sommerfeld type, in the periodic case, discrete sums over sampled values of the same spectra are required. When source and observation points are in the same or in adjacent layers, the convergence of both representations is enhanced by isolating the direct and quasi-static image contributions associated with the nearby layers. In the periodic case, the convergence of direct and image contributions may be rapidly accelerated by means of the Ewadd method.
Date: March 27, 1998
Creator: Wilton, D. R.; Jackson, D. R. & Champagne, N. J.
System: The UNT Digital Library
Multilayer ultra high gradient insulator technology (open access)

Multilayer ultra high gradient insulator technology

We are investigating a novel insulator concept which involves the use of alternating layers of conductors and insulators with periods less than 1 mm. These structures perform many times better (about 1.5 to 4 times higher breakdown electric field) than conventional insulators in long pulse, short pulse, and alternating polarity applications. We present our ongoing studies investigating the degradation of the breakdown electric field resulting from surface roughness, the effect of gas pressure, and the performance of the insulator structure under bi-polar stress. Further, we present our initial modeling studies.
Date: March 27, 1998
Creator: Sampayan, S. E.; Vitello, P. A.; Krogh, M. L. & Elizondo, J. M.
System: The UNT Digital Library
The gene identification problem: An overview for developers (open access)

The gene identification problem: An overview for developers

The gene identification problem is the problem of interpreting nucleotide sequences by computer, in order to provide tentative annotation on the location, structure, and functional class of protein-coding genes. This problem is of self-evident importance, and is far from being fully solved, particularly for higher eukaryotes, Thus it is not surprising that the number of algorithm and software developers working in this area is rapidly increasing. The present paper is an overview of the field, with an emphasis on eukaryotes, for such developers.
Date: March 27, 1995
Creator: Fickett, J.W.
System: The UNT Digital Library
A comparison of interface tracking methods (open access)

A comparison of interface tracking methods

In this Paper we provide a direct comparison of several important algorithms designed to track fluid interfaces. In the process we propose improved criteria by which these methods are to be judged. We compare and contrast the behavior of the following interface tracking methods: high order monotone capturing schemes, level set methods, volume-of-fluid (VOF) methods, and particle-based (particle-in-cell, or PIC) methods. We compare these methods by first applying a set of standard test problems, then by applying a new set of enhanced problems designed to expose the limitations and weaknesses of each method. We find that the properties of these methods are not adequately assessed until they axe tested with flows having spatial and temporal vorticity gradients. Our results indicate that the particle-based methods are easily the most accurate of those tested. Their practical use, however, is often hampered by their memory and CPU requirements. Particle-based methods employing particles only along interfaces also have difficulty dealing with gross topology changes. Full PIC methods, on the other hand, do not in general have topology restrictions. Following the particle-based methods are VOF volume tracking methods, which are reasonably accurate, physically based, robust, low in cost, and relatively easy to implement. Recent enhancements …
Date: March 27, 1995
Creator: Kothe, D.B. & Rider, W. J.
System: The UNT Digital Library
Analysis of soil-structure interaction due to ambient vibration (open access)

Analysis of soil-structure interaction due to ambient vibration

This paper presents the results of a study to evaluate the effects of soil-structure interaction (SSI) on the ambient vibration response of the switchyard/target area (S/TA) buildings at the National Ignition Facility (NIF) presently under construction at the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. This laser facility houses optical and other special equipment whose alignment stability is sensitive to vibrations caused by ambient vibrations or other vibrating sources. In evaluating the deformations and displacements of the S/TA structures, the contribution of the SSI to the overall system flexibility can be very significant. The present study examines the results of fixed-base and SSI analyses of these massive stiff structures to develop an understanding of the potential contribution of SSI to the overall system displacements and deformations. A simple procedure using a set of factors is recommended for scaling the results of fixed-base analyses to approximately account for SSI effects.
Date: March 27, 1998
Creator: Tabatabaie, M., Sommer, S.C.
System: The UNT Digital Library
Optical pulse generation using fiber lasers and integrated optics (open access)

Optical pulse generation using fiber lasers and integrated optics

We have demonstrated an optical pulse forming system using fiber and integrated optics, and have designed a multiple-output system for a proposed fusion laser facility. Our approach is an advancement over previous designs for fusion lasers, and an unusual application of fiber lasers and integrated optics.
Date: March 27, 1995
Creator: Wilcox, R. B.; Browning, D. F.; Burkhart, S. C. & VanWonterghem, B. W.
System: The UNT Digital Library
810 Future plans (open access)

810 Future plans

It is believed that a good bet for finding the Quark-Gluon Plasma at AGS energies is with the heaviest projectiles on the heaviest target, i.e. Au on Au. One of the likely signatures of the plasma is strangeness enhancement. Al Saulys has shown what it's like to find {Delta} and K{degree} with Si projectiles. Our Monte Carlo simulations show track densities 4 times higher for Au projectiles. In addition, the Au beam itself produces 30 times more ionization. Thus the present TPC's will be limited to only a few hundred ions per sec. This paper discusses plans for these experiments and modification to TPC. 9 figs.
Date: March 27, 1990
Creator: Etkin, A.; Foley, K. J.; Hackenburg, R. W.; Longacre, R. S.; Love, W. A.; Morris, T. W. et al.
System: The UNT Digital Library