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The EQ3/6 software package for geochemical modeling: Current status (open access)

The EQ3/6 software package for geochemical modeling: Current status

EQ3/6 is a software package for modeling chemical and mineralogic interactions in aqueous geochemical systems. The major components of the package are EQ3NR (a speciation-solubility code), EQ6 (a reaction path code), EQLIB (a supporting library), and a supporting thermodynamic data base. EQ3NR calculates aqueous speciation and saturation indices from analytical data. It can also be used to calculate compositions of buffer solutions for use in laboratory experiments. EQ6 computes reaction path models of both equilibrium step processes and kinetic reaction processes. These models can be computed for closed systems and relatively simple open systems. EQ3/6 is useful in making purely theoretical calculations, in designing, interpreting, and extrapolating laboratory experiments, and in testing and developing submodels and supporting data used in these codes. The thermodynamic data base supports calculations over the range 0-300{degree}C. 60 refs., 2 figs.
Date: July 1, 1988
Creator: Wolery, T. J.; Jackson, K. J.; Bourcier, W. L.; Bruton, C. J.; Viani, B. E.; Knauss, K. G. et al.
System: The UNT Digital Library
The search for high level parallelism for the iterative solution of large sparse linear systems (open access)

The search for high level parallelism for the iterative solution of large sparse linear systems

In this paper the author is concerned with the numerical solution, based on iterative methods, of large sparse systems of linear algebraic equations of the type which arise in the numerical solution of elliptic and parabolic partial differential equations by finite difference or finite element methods. He considers linear systems of the form Au = b where A is a given N x N matrix which is large and sparse and where b is a given N x 1 column vector. He will assumes that A is symmetric and positive definite (SPD). He considers iterative algorithms which consist of a basic iterative method, such as the Richardson, Jacobi, SSOR or incomplete Cholesky method, combined with an acceleration procedure such as Chebyshev acceleration or conjugate gradient acceleration. The object of this paper is, however, to examine some high-level methods for achieving parallelism. Such techniques involve only matrix/vector operations and do not involve working with blocks of the matrix, subdividing the region, or using different meshes. It is expected that if effective high-level methods could be developed, they could be combined with block and domain decomposition methods, and related methods, to obtain even greater speedups. It is also expected that by working …
Date: July 1, 1988
Creator: Young, D.M.
System: The UNT Digital Library
The Cryogenic System for the ASTROMAG Test Coil (open access)

The Cryogenic System for the ASTROMAG Test Coil

This paper describes an all helium, low heat leak cryogenic system for the testing of a superconducting magnet coil for the ASTROMAG particle astrophysics experiment. The superconducting coil, which is projected to have a stored magnetic energy of 4 to 7 MJ, will be cooled by pumped helium from a liquid helium storage tank using a fountain effect helium II pump. The pumping system can be used to cool the cryogenic system down as well as keep the coil cold during its superconducting operation. The integration of retractable 900 A gas-cooled electrical leads with the intermediate shields and intercepts is discussed.
Date: July 1, 1988
Creator: Green, M. A.; Levine, S. M.; Smoot, G. F. & Witebsky, C.
System: The UNT Digital Library
Nonlinear Spin Acceptance in Electron Storage Rings (open access)

Nonlinear Spin Acceptance in Electron Storage Rings

It is shown that the degree of polarization of a beam in electron storage rings can be limited by nonlinear effects. The strength of a nonlinear effect depends on theamplitude of the particles. Particles performing synchrotron and betatron oscillations with high amplitudes can contribute over proportionally to depolarization. As aresult, the emittance of a beam is not allowed to exceed certain boundaries, otherwise the beam will become more and more depolarized. This limit is called nonlinearspin acceptance.
Date: July 1, 1988
Creator: Kewisch, Jorg & Rossmanith, Robert
System: The UNT Digital Library
Use of cermet fueled nuclear reactors for direct nuclear propulsion (open access)

Use of cermet fueled nuclear reactors for direct nuclear propulsion

There has been a renewal of interest in Direct Nuclear Propulsion (DNP) because of the Air Force Forecast II recommendation for the development of the technology. Several nuclear concepts have been proposed to meet the Direct Nuclear Propulsion challenge. In this paper we will present results of an initial study of the potential of a cermet fueled nuclear system in providing the desired DNP capabilities and featuring a set of unique safety characteristics. The concept of cermet fuel for DNP applications was first developed by ANL and GE working independently more than 20 years ago. The two organizations came to several remarkably consistent conclusions. The present work has consisted of collecting a unified set of design parameters from the set of design results produced in the earlier work. The conclusion of this exercise was that a cermet-fueled DNP design looked extremely promising from performance and safety considerations and that it deserves serious consideration when the decision to develop one or more concepts for DNP is made.
Date: July 1, 1988
Creator: Bhattacharyya, S. K.; Carlson, L. W.; Kuczen, K. D.; Hanan, N. A.; Palmer, R. G.; Von Hoomissen, J. et al.
System: The UNT Digital Library
Prospects for understanding the astrophysical r-process (open access)

Prospects for understanding the astrophysical r-process

This paper discusses several recent advances toward a deeper understanding of the still unknown astrophysical site for rapid (r-process) neutron capture nucleosynthesis. The physical constraints on the r-process from the input nuclear data are highlighted and the particular importance of the recent measurements of beta-decay lifetimes along the r-process path is discussed. Astronomical observations of s- and r-process elemental abundances on metal poor halo stars are also discussed, in the context of models for the galactic chemical evolution of heavy-element abundances, as a constraint on the nature of the r-process. On the basis of these constraints it is suggested that the most likely source for the r-process may be from the ejection of core material from low-mass type II supernovae. 27 refs., 1 fig.
Date: July 1, 1988
Creator: Mathews, G. J. & Cowan, J. J.
System: The UNT Digital Library
Intermediate-range order in binary and ternary glasses (open access)

Intermediate-range order in binary and ternary glasses

Intermediate-range order in binary and ternary chalcogenide glasses is discussed, with special reference to GeSe/sub 2/ and Ag/sub 4/Ge/sub 3/Se/sub 9/. A signature of this order is provided by the first sharp diffraction peak, which occurs in these glasses at Q /approximately/ 1 /sup /angstrom/A//sup /minus/1/ and shows anomalous behavior in several ways. It is strongly depressed by the addition of Ag to the GeSe/sub 2/ glass. The addition of Ag also leads to a softening of the vibrational spectrum. 11 refs., 4 figs.
Date: July 1, 1988
Creator: Price, D. L.; Susman, S.; Volin, K. J. & Dejus, R. J.
System: The UNT Digital Library
Photon-photon collisions (open access)

Photon-photon collisions

Highlights of the VIIIth International Workshop on Photon-Photon Collisions are reviewed. New experimental and theoretical results were reported in virtually every area of ..gamma gamma.. physics, particularly in exotic resonance production and tests of quantum chromodynamics where asymptotic freedom and factorization theorems provide predictions for both inclusive and exclusive ..gamma gamma.. reactions at high momentum transfer. 73 refs., 12 figs.
Date: July 1, 1988
Creator: Brodsky, Stanley J.
System: The UNT Digital Library
Bunch coalescing and bunch rotation in the Fermilab Main Ring: Operational experience and comparison with simulations (open access)

Bunch coalescing and bunch rotation in the Fermilab Main Ring: Operational experience and comparison with simulations

The Fermilab Tevatron I proton-antiproton collider project requires that the Fermilab Main Ring produce intense bunches of protons and antiprotons for injection into the Tevatron. The process of coalescing a small number of harmonic number h=1113 bunches into a single bunch by bunch-rotating in a lower harmonic rf system is described.The Main Ring is also required to extract onto the antiproton production target bunches with as narrow a time spread as possible. This operation is also discussed. The operation of the bunch coalescing and bunch rotation are compared with simulations using the computer program ESME. 2 refs., 8 figs.
Date: July 1, 1988
Creator: Martin, P.S. & Wildman, D.W.
System: The UNT Digital Library
Some ideas on the advantages of soft x-rays as imaging particles (open access)

Some ideas on the advantages of soft x-rays as imaging particles

This paper discusses uses of soft x-rays as imaging particles. Particular topics discussed are: Soft x-ray as a biological probe; overview of x-ray microscope techniques; analysis of the usefulness of x-rays in imaging and microanalysis; and physical radiation damage. 27 refs., 3 figs., 1 tab.
Date: July 1, 1988
Creator: Howells, M.
System: The UNT Digital Library
New approach to high energy SU/sub 2L/ /times/ U/sub 1/ radiative corrections (open access)

New approach to high energy SU/sub 2L/ /times/ U/sub 1/ radiative corrections

We present a new approach to SU/sub 2L/ /times/ U/sub 1/ radiative corrections at high energies. Our approach is based on the infrared summation methods of Yennie, Frautschi and Suura, taken together with the Weinberg-'t Hooft renormalization group equation. Specific processes which have been realized via explicit Monte Carlo algorithms are e/sup +/e/sup /minus// ..-->.. f/bar f/' + n(..gamma..), f = ..mu.., /tau/, d, s, u, c, b or t and e/sup +/e/sup /minus// ..-->.. e/sup +/e/sup /minus// + n(..gamma..), where n(..gamma..), denotes multiple photo emission on an event-by-event basis. Exemplary Monte Carlo data are presented. 16 refs., 4 figs.
Date: July 1, 1988
Creator: Ward, B.F.L.
System: The UNT Digital Library
Discrete physics: Practice, representation and rules of correspondence (open access)

Discrete physics: Practice, representation and rules of correspondence

We make a brief historical review of some aspects of modern physics which we find most significant in our own endeavor. We discuss the ''Yukawa Vertices'' of elementary particle theory as used in laboratory practice, second quantized field theory, analytic S-Matrix theory and in our own approach. We review the conserved quantum numbers in the Standard Model of quarks and leptons. This concludes our presentation of the ''E-frame.'' We try to develop a self-consistent representation of our theory. We have already claimed that this approach provides a discrete reconciliation between the formal (representational) aspects of quantum mechanics and relativity. Also discussed are rules of correspondence connecting the formalism to the practice of physics by using the counter paradigm and event-based coordinates to construct relativistic quantum mechanics in a new way. 31 refs., 12 figs., 1 tab.
Date: July 1, 1988
Creator: Noyes, H. Pierre
System: The UNT Digital Library
Electron pair production in p + Be and Ca + Ca collisions at the Bevalac (open access)

Electron pair production in p + Be and Ca + Ca collisions at the Bevalac

We report on the measurements of direct electron pair production in p-Be interactions at 1.0, 2.1 and 4.9 GeV and Ca + Ca at 1.0 and 2.0 GeV/A. The distributions of invariant mass and p/sub t/ are presented along with the total cross section. We observe a structure in the invariant mass spectra at approximately 275 MeV for 2.0 and 4.9 GeV p + Be data. A rapid decrease in the p + Be total cross-section is observed between 2.1 and 1.0 GeV. Both observations are consistent with the interpretation that pion-pion annihilations dominate production mechanism. 10 refs., 3 figs., 1 tab.
Date: July 1, 1988
Creator: Naudet, C.; Carroll, J.; Gordon, J.; Hallman, T.; Igo, G.; Kirk, P. et al.
System: The UNT Digital Library
Conceptual design of a superconducting solenoid for a magnetic SSC (Superconducting Super Collider) detector (open access)

Conceptual design of a superconducting solenoid for a magnetic SSC (Superconducting Super Collider) detector

The conceptual design of a large superconducting solenoid suitable for a magnetic detector at the Superconducting Super Collider (SSC) has begun at Fermilab. The magnet will provide a magnetic field of 2 T over a volume 8 m in diameter by 16 m long. The particle-physics calorimetry will be inside the field volume and so the coil will be bath cooled and cryostable; the vessels will be stainless steel. Predictibility of performance and the ability to safely negotiate all probable failure modes, including a quench, are important items of the design philosophy. Although the magnet is considerably larger than existing solenoids of this type and although many issues of manufacturability, transportability and cost have not been completely addressed, our conceptual design has convinced us that this magnet is a reasonable extrapolation of present technology. 2 figs., 2 tabs.
Date: July 1, 1988
Creator: Fast, R. W.; Grimson, J. H.; Kephart, R. D.; Krebs, H. J.; Stone, M. E.; Theriot, D. et al.
System: The UNT Digital Library
Radiative widths of resonances (experiments) (open access)

Radiative widths of resonances (experiments)

After a hiatus of several years, this conference brings us considerable new data on resonance production in photon photon interactions. I will first discuss the contributions concerning the tensor, pseudoscalar and scalar mesons, then review the current status of the (c/ovr string/c /eta//sub c/) and finally summarize the exciting new results concerning the spin 1 mesons. 40 refs., 21 figs., 7 tabs.
Date: July 1, 1988
Creator: Gidal, G.
System: The UNT Digital Library
PEGASYS---A proposed internal target facility for the PEP storage ring (open access)

PEGASYS---A proposed internal target facility for the PEP storage ring

A proposal for an integral gas-jet target and forward spectrometer for the PEP storage ring is described. The beam structure, allowable, luminosity (L = 10/sup 33/ cm/sup /minus/2/s/sup /minus/1/ for H/sub 2/, D/sub 2/) and energy (E/sub e/ less than or equal to 15 GeV) make the ring ideal for multiparticle coincidence studies in the scaling regime, and where perturbative QCD may be an apt description of some exclusive and semi-inclusive reactions. 14 refs., 7 figs.
Date: July 1, 1988
Creator: Van Biber, K.
System: The UNT Digital Library
Summary of the Relativistic Heavy Ion Sessions (open access)

Summary of the Relativistic Heavy Ion Sessions

This paper briefly discusses the topics covered in the relativistic heavy ion in sessions. The prime motivation for these investigations is the possibility of forming quark matter, therefore the formation of a quark-gluon plasma. Topics on suppression of J//psi/ production, th equation of state of nuclear matter, transverse energy distributions and two pion interferometry techniques are discussed. 38 refs. (LSP)
Date: July 1, 1988
Creator: Harris, J. W.
System: The UNT Digital Library
MAGNETIC FIELD PENETRATION INTO THE HIGH TEMPERATURE SUPERCONDUCTOR. YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/ (open access)

MAGNETIC FIELD PENETRATION INTO THE HIGH TEMPERATURE SUPERCONDUCTOR. YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/

The penetration depth of a magnetic field into a superconducting YBa/sub 2/Cu/sub 3/O/sub 7-x/ film was measured by polarized neutron reflection. The sample comprised an epitaxial film with the c-axis of its orthorhombic structure perpendicular to the film's surface. Measurements at 14 K showed that a magnetic field (parallel to the surface) penetrates into the surface over a depth of 1400 /angstrom/. 9 refs., 3 figs.
Date: July 1, 1988
Creator: Mansour, A.; Hilleke, R. O.; Felcher, G. P.; Laibowitz, R. B.; Chaudhari, P. & Parkin, S. S. P.
System: The UNT Digital Library
SURFACE ENRICHMENT IN POLYMER BLENDS: A neutron reflection test (open access)

SURFACE ENRICHMENT IN POLYMER BLENDS: A neutron reflection test

In polymer melts of protonated and deuterated polystyrene (PS and d-PS) surface segregation of the d-PS occurs at temperatures and compositions in the one phase region close to the coexistence curve for phase separation. A neutron reflection test on a polymer blend containing 10% volume fraction of d-PS has shown that a thermal treatment caused a surface enrichment of d-PS up to 28%. The experiment demonstrates that neutron reflection measurements can generate detailed information on surface enrichment phenomena in polymer blends.
Date: July 1, 1988
Creator: Composto, R. J.; Stein, R. S.; Kramer, E. J.; Jones, R. A. L.; Mansour, A.; Karim, A. et al.
System: The UNT Digital Library
Using the /phi/resund experimental data to evaluate the ARAC emergency response models (open access)

Using the /phi/resund experimental data to evaluate the ARAC emergency response models

A series of meteorological and tracer experiments, was conducted during May and June 1984 over the 20-km wide /O/resund strait between Denmark and Sweden for the purpose of studying atmospheric dispersion processes over cold water and warm land surfaces and providing the data needed to evaluate meso-scale models in a coastal environment. In concert with these objectives the data from these experiments have been used as part of a continuing effort to evaluate the capability of the three-dimensional MATHEW/ADPIC (M/A) atmospheric dispersion models to simulate pollutant transport and diffusion characteristics of the atmospheric during a wide variety of meteorological conditions. Since previous studies have focused primarily on M/A model evaluations over rolling and complex terrain at inland sites, the /O/resund experiments provide a unique opportunity to evaluate the models in a coastal environment. The M/A models are used by the Atmospheric Release Advisory Capability (ARAC), developed by the Lawrence Livermore National Laboratory, for performing real-time assessments of the environmental consequences of potential or actual releases of radioactivity into the atmosphere. These assessments include estimation of radiation doses to nearby population centers and of the extent of surface contamination. Model evaluations, using field experimental data such as those generated by the …
Date: July 1, 1988
Creator: Gudiksen, Paul H. & Gryning, Sven-Erik
System: The UNT Digital Library
Theory and Analysis of Nonlinear Dynamics and Stability in Storage Rings: A Working Group Summary (open access)

Theory and Analysis of Nonlinear Dynamics and Stability in Storage Rings: A Working Group Summary

A summary and commentary of the available theoretical and analytical tools and recent advances in the nonlinear dynamics, stability and aperture issues in storage rings are presented. 11 refs., 4 figs.
Date: July 1, 1988
Creator: Chattopadhyay, S.; Audy, P.; Courant, E. D.; Forest, E.; Guignard, G.; Hagel, J. et al.
System: The UNT Digital Library
Response of materials to high heat fluxes during operation in fusion reactors (open access)

Response of materials to high heat fluxes during operation in fusion reactors

Very high energy deposition on first wall and other components of a fusion reactor is expected due to plasma instabilities during both normal and off-normal operating conditions. Off-normal operating conditions result from plasma disruptions where the plasma loses confinement and dumps its energy on the reactor components. High heat flux may also result from normal operating conditions due to fluctuations in plasma edge conditions. This high energy dump in a short time results in very high surface temperatures and may consequently cause melting and vaporization of these materials. The net erosion rates resulting from melting and vaporization are very important to estimate the lifetime of such components. The response of different candidate materials to this high heat fluxes is determined for different energy densities and deposition times. The analysis used a previously developed model to solve the heat conduction equation in two moving boundaries. One moving boundary is at the surface to account for surface recession due to vaporization and the second moving boundary is to account for the solid-liquid interface inside the material. The calculations are done parametrically for both the expected energy deposited and the deposition time. These ranges of energy and time are based on recent experimental …
Date: July 1, 1988
Creator: Hassanein, A.M.
System: The UNT Digital Library
Electron-positron collision physics: 1 MeV to 2 TeV (open access)

Electron-positron collision physics: 1 MeV to 2 TeV

An overview of electron-positron collision physics is presented. It begins at 1 MeV, the energy region of positronium formation, and extends to 2 TeV, the energy region which requires an electron- positron linear collider. In addition, the concept of searching for a lepton-specific forces is discussed. 18 refs., 15 figs., 1 tab.
Date: July 1, 1988
Creator: Perl, Martin L.
System: The UNT Digital Library
Cosmic strings (open access)

Cosmic strings

Cosmic strings are linear topological defects that are predicted by some grand unified theories to form during a spontaneous symmetry breaking phase transition in the early universe. They are the basis for the only theories of galaxy formation aside from quantum fluctuations from inflation that are based on fundamental physics. In contrast to inflation, they can also be observed directly through gravitational lensing and their characteristic microwave background anistropy. It has recently been discovered by F. Bouchet and myself that details of cosmic string evolution are very different from the so-called ''standard model'' that has been assumed in most of the string induced galaxy formation calculations. Therefore, the details of galaxy formation in the cosmic string models are currently very uncertain. 29 refs., 9 figs.
Date: July 1, 1988
Creator: Bennett, D.P.
System: The UNT Digital Library