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Systems modeling for heavy ion drivers - an induction linac example (open access)

Systems modeling for heavy ion drivers - an induction linac example

A source-to-target model for a induction linac driver for heavy ion fusion has been developed and is described here. Design features for a reference case driver that meets the requirements of one current target design are given, and the systems analyses supporting the point design are discussed. Directions for future work are noted.
Date: September 30, 1997
Creator: Meier, W. R.; Bangerter, R. O. & Faltens, A.
System: The UNT Digital Library
Analysis of classical transport equations for the Tokamak edge plasma (open access)

Analysis of classical transport equations for the Tokamak edge plasma

The classical fluid transport equations for a magnet-plasma as given, for example, by Braginskii [1], are complicated in their most general form. Here we obtain the simplest reduced set which contains the essential physics of the tokamak edge problem in slab geometry by systematically applying a parameter ordering and making use of specific symmetries. An important ingredient is a consistent set of boundary conditions as described elsewhere [2]. This model clearly resolves some important issues concerning diamagnetic drifts, high parallel viscosity, and the ambipolarity constraint. The final equations can also serve as a model for understanding the structure of the equations in the presence of anomalous transport terms arising from fluctuations. In fact, Braginskii-like equations are the basis of a number of scrape-off layer (SOL) transport codes [3]. However, all of these codes contain ad hoc radial diffusion terms and often neglect some classical terms, both of which make the self-consistency of the models questionable. Braginskii's equations [1] have been derived from the first principles via the kinetic equations and, thereby, contain such ''built-in'' features as the symmetry of kinetic coefficients, and automatic quasineutrality of a cross-field diffusion in a system with toroidal symmetry such as a tokamak. Our model …
Date: September 29, 1997
Creator: Rognlien, T. D., LLNL
System: The UNT Digital Library
Next-generation laser for Inertial Confinement Fusion (open access)

Next-generation laser for Inertial Confinement Fusion

We report on the progress in developing and building the Mercury laser system as the first in a series of a new generation of diode- pumped solid-state Inertial Confinement Fusion (ICF) lasers at Lawrence Livermore National Laboratory (LLNL). Mercury will be the first integrated demonstration of a scalable laser architecture compatible with advanced high energy density (HED) physics applications. Primary performance goals include 10% efficiencies at 10 Hz and a 1-10 ns pulse with 1 omega energies of 100 J and with 2 omega/3 omega frequency conversion.
Date: September 29, 1997
Creator: Marshall, C.D.; Deach, R.J. & Bibeau, C.
System: The UNT Digital Library
Picosecond nonradiative processes in neodymium-doped crystals and glasses: mechansim for the energy gap law (open access)

Picosecond nonradiative processes in neodymium-doped crystals and glasses: mechansim for the energy gap law

We present measurements of the 4G7/2 emission lifetime for 26 Nd-doped materials. A model of nonradiative decay based on dipole-dipole energy transfer is developed and found to be supported by our data.
Date: September 29, 1997
Creator: Bibeau, C. & Payne, S.A.
System: The UNT Digital Library
Corrosion mechanisms of spent fuel under oxidizing conditions (open access)

Corrosion mechanisms of spent fuel under oxidizing conditions

The release of {sup 99}Tc can be used as a reliable marker for the extent of spent oxide fuel reaction under unsaturated high-drip-rate conditions at 90{degrees}C. Evidence from leachate data and from scanning and transmission electron microscopy (SEM and TEM) examination of reacted fuel samples is presented for radionuclide release, potential reaction pathways, and the formation of alteration products. In the ATM-103 fuel, 0.03 of the total inventory of {sup 99}Tc is released in 3.7 years under unsaturated and oxidizing conditions. Two reaction pathways that have been identified from SEM are (1) through-grain dissolution with subsequent formation of uranyl alteration products, and (2) grain-boundary dissolution. The major alteration product identified by x-ray diffraction (XRD) and SEM, is Na-boltwoodite, Na[(UO{sub 2})(SiO{sub 3}OH)]{lg_bullet}H{sub 2}O, which is formed from sodium and silicon in the water leachant.
Date: September 27, 1997
Creator: Finn, P.A.; Finch, R.; Buck, E. & Bates, J.
System: The UNT Digital Library
Innovative Composite Wall System for Sheathing Masonry Walls (open access)

Innovative Composite Wall System for Sheathing Masonry Walls

Existing Housing - Much of the older multifamily housing stock in the United States includes units in structures with uninsulated masonry walls. Included in this stock are two- and three-story walk-up apartments, larger apartment complexes, and public housing (both high- rise and townhouse). This older multifamily housing has seen years of heavy use that may have left the plaster wall marred or damaged. Long- term building settlement or movement may have cracked the plaster, sometimes severely. Moisture from invented kitchens and baths may have caused condensation on uninsulated exterior walls. At best this condensation has left stains on the paint or wallpaper. At worst it has supported mold and mildew growth, fouling the air and creating unhealthy living conditions. Deteriorating plaster and flaking paint also result from wet walls. The presence of flaking, lead-based paint in older (pre-1978) housing is a major public health concern. Children can suffer permanent mental handicaps and psychological disorders if they are subjected to elevated levels of lead, while adults can suffer hypertension and other maladies. Studies have found that, in some urban communities with older housing stocks, over 35% of children tested have elevated blood lead levels (Hastings, et al.: 1997). Nationally, nearly 22% …
Date: September 25, 1997
Creator: Wendt, Robert L. & Cavallo, James
System: The UNT Digital Library
Absorptance measurements of transmissive optical components by the surface thermal lensing technique (open access)

Absorptance measurements of transmissive optical components by the surface thermal lensing technique

The surface thermal lensing technique (STL) successfully resolved and measured the absorptance of transmissive optical components: near- normal angle-of-incidence anti-reflectors and beam splatters. The STL system uses an Ar ion laser to pump the components at 514.5 mn. The absorptance-induced surface deformation diffracts the HeNe probe beam into a photo-detector. The signal intensity was calibrated with a sample of known absorptance. The optical components were designed to function in a copper vapor laser (CVL) transport system, and were previously tested for absorptance with a high power CVL system at 511 rtm. To assure proper absorptance data from the STL system, the pump laser power densities were set at the operational level of the coatings, absorptance time trends were monitored, and absorptance area scans were made. Both types of transmissive optics are more stable than the CVL high reflectors that were measured in another study. Parameter studies based on Fresnel diffraction theory were also performed to optimize experimental condition. The STL system was assessed to have 10 ppb sensitivity for absorption measurement given 2 W of pump power.
Date: September 24, 1997
Creator: Chow, R.; Taylor, J. R.; Wu, Z. L.; Han, Y. & Tian, L. Y.
System: The UNT Digital Library
Long-term global nuclear energy and fuel cycle strategies (open access)

Long-term global nuclear energy and fuel cycle strategies

The Global Nuclear Vision Project is examining, using scenario building techniques, a range of long-term nuclear energy futures. The exploration and assessment of optimal nuclear fuel-cycle and material strategies is an essential element of the study. To this end, an established global E{sup 3} (energy/economics/environmental) model has been adopted and modified with a simplified, but comprehensive and multi-regional, nuclear energy module. Consistent nuclear energy scenarios are constructed using this multi-regional E{sup 3} model, wherein future demands for nuclear power are projected in price competition with other energy sources under a wide range of long-term demographic (population, workforce size and productivity), economic (price-, population-, and income-determined demand for energy services, price- and population-modified GNP, resource depletion, world-market fossil energy prices), policy (taxes, tariffs, sanctions), and top-level technological (energy intensity and end-use efficiency improvements) drivers. Using the framework provided by the global E{sup 3} model, the impacts of both external and internal drivers are investigated. The ability to connect external and internal drivers through this modeling framework allows the study of impacts and tradeoffs between fossil- versus nuclear-fuel burning, that includes interactions between cost, environmental, proliferation, resource, and policy issues.
Date: September 24, 1997
Creator: Krakowski, R. A.
System: The UNT Digital Library
ORCMT -- technology resource for the 21. century nonwovens industry (open access)

ORCMT -- technology resource for the 21. century nonwovens industry

As American textile and nonwovens companies participate in an increasingly competitive world market, technology is playing an ever-growing role in production of new, improved, and more cost competitive products and processes. But the same competitive pressures which drive the need for advanced manufacturing technology also reduce the resources available for necessary research and development activities. Technology resources and manufacturing expertise, unmatched in the world, are available to American industry at the Oak Ridge Centers for Manufacturing Technology (ORCMT). Bottom-line benefits from ORCMT technology solutions are already in the hundreds of millions of dollars. This presentation will describe a sampling of the technologies and expertise available, present examples of previous solutions, and explain how a company can benefit from the wealth of resources available.
Date: September 24, 1997
Creator: Whittaker, J.W.
System: The UNT Digital Library
Self-Dual Supergravity from N = 2 Strings (open access)

Self-Dual Supergravity from N = 2 Strings

A new heterotic N = 2 string with manifest target space supersymmetry is constructed by combining a conventional N = 2 string in the right-moving sector and a Green-Schwarz-Berkovits type string in the left-moving sector. The corresponding sigma model is then obtained by turning on background fields for the massless excitations. We compute the beta functions and we partially check the OPE's of the superconformal algebra perturbatively in {alpha}{prime}, all in superspace. The resulting field equations describe N = 1 self-dual supergravity.
Date: September 24, 1997
Creator: de Boer, J. & Skenderis, K.
System: The UNT Digital Library
Non-equilibrium many body dynamics (open access)

Non-equilibrium many body dynamics

This Riken BNL Research Center Symposium on Non-Equilibrium Many Body Physics was held on September 23-25, 1997 as part of the official opening ceremony of the Center at Brookhaven National Lab. A major objective of theoretical work at the center is to elaborate on the full spectrum of strong interaction physics based on QCD, including the physics of confinement and chiral symmetry breaking, the parton structure of hadrons and nuclei, and the phenomenology of ultra-relativistic nuclear collisions related to the up-coming experiments at RHIC. The opportunities and challenges of nuclear and particle physics in this area naturally involve aspects of the many body problem common to many other fields. The aim of this symposium was to find common theoretical threads in the area of non-equilibrium physics and modern transport theories. The program consisted of invited talks on a variety topics from the fields of atomic, condensed matter, plasma, astrophysics, cosmology, and chemistry, in addition to nuclear and particle physics. Separate abstracts have been indexed into the database for contributions to this workshop.
Date: September 22, 1997
Creator: Creutz, M. & Gyulassy, M.
System: The UNT Digital Library
Magnetic core studies at LBNL and LLNL (open access)

Magnetic core studies at LBNL and LLNL

The objective of this work is to minimize the cost of the materials and maximize the performance of magnetic cores, a major cost component of a Heavy-Ion-Fusion, HIF, induction accelerator driver. This includes selection of the alloy for cost and performance, and maximizing the performance of each alloy evaluated. The two major performance parameters are the magnetic flux swing and the energy loss. The volt seconds of the cores, obtained from the flux swing with Faraday's Law, determines the beam energy and duration. Core losses from forming domains and moving their boundaries are a major factor in determining the efficiency of an induction accelerator.
Date: September 20, 1997
Creator: Molvik, A.W.; Faltens, A.; Reginato, L.; Blaszkiewicz, M.; Smith, C. & Wood, R.
System: The UNT Digital Library
Negative contributions to S in an effective field theory (open access)

Negative contributions to S in an effective field theory

We show that an effective field theory that includes non-standard couplings between the electroweak gauge bosons and the top and bottom quarks may yield negative contributions to both the S and T oblique radiative electroweak parameters. We find that such an effective field theory provides a better fit to data than the standard model (the {chi}{sup 2} per degree of freedom is half as large). We examine in some detail an illustrative model where the exchange of heavy scalars produces the correct type of non-standard couplings.
Date: September 19, 1997
Creator: Dobrescu, Bogdan A. & Terning, John
System: The UNT Digital Library
W.E. Henry Symposium compendium: The importance of magnetism in physics and material science (open access)

W.E. Henry Symposium compendium: The importance of magnetism in physics and material science

This compendium contains papers presented at the W. E. Henry Symposium, The Importance of Magnetism in Physics and Material Science. The one-day symposium was conducted to recognize the achievements of Dr. Warren Elliot Henry as educator, scientist, and inventor in a career spanning almost 70 years. Dr. Henry, who is 88 years old, attended the symposium. Nobel Laureate, Dr. Glenn Seaborg, a friend and colleague for over 40 years, attended the event and shared his personal reminiscences. Dr. Seaborg is Associate Director-At-Large at the Lawrence Berkeley National Laboratory. The Compendium begins with three papers which demonstrate the ongoing importance of magnetism in physics and material science. Other contributions cover the highlights of Dr. Henry`s career as a researcher, educator, and inventor. Colleagues and former students share insights on the impact of Dr. Henry`s research in the field of magnetism, low temperature physics, and solid state physics; his influence on students as an educator; and his character, intellect and ingenuity, and passion for learning and teaching. They share a glimpse of the environment and times that molded him as a man, and the circumstances under which he made his great achievements despite the many challenges he faced.
Date: September 19, 1997
Creator: Carwell, H.
System: The UNT Digital Library
Muon dynamics in a toroidal sector magnet (open access)

Muon dynamics in a toroidal sector magnet

The present scenario for the cooling channel in a high brightness muon collider calls for a quasi-continuous solenoidal focusing channel. The beam line consists of a periodic array of rf cavities and approximately 2 cm long LiH absorbers immersed in a solenoid with alternating focusing field (FOFO). The authors present a Hamiltonian formulation of muon dynamics in toroidal sector solenoids (bent solenoid).
Date: September 17, 1997
Creator: Gallardo, J. C.; Fernow, R. & Palmer, R. B.
System: The UNT Digital Library
Total energy-cycle energy and emissions impacts of hybrid electric vehicles (open access)

Total energy-cycle energy and emissions impacts of hybrid electric vehicles

Argonne National Laboratory has begun an analysis of the energy and air emission impacts of hybrid electric vehicles (HEVs) over the entire energy cycle, including manufacturing, operating, and recycling the vehicles and producing their fuel. Phase 1 evaluates series HEVs using lead acid and nickel metal hydride batteries, operating independent of the electricity grid and connected to it, and compares them to conventional ICE vehicles. With efficient electric components, both grid-dependent and grid-independent vehicles are more efficient than their conventional counterpart, though most of the efficiency advantage is gained in slow, lower power operation (e.g., on the federal urban driving schedule). The grid-independent HEV is not clearly superior if it operates part of each day with grid electricity. Finally, estimates of lead emissions for the lead acid battery-powered HEV are significantly lower than suggested elsewhere.
Date: September 17, 1997
Creator: Wang, M. Q.; Plotkin, S.; Santini, D. J.; He, J.; Gaines, L. & Patterson, P.
System: The UNT Digital Library
The VIIth Blois workshop: Theory summary and factorization issues (open access)

The VIIth Blois workshop: Theory summary and factorization issues

Theory presentations at this workshop have covered a wide range of topics. In addition to the traditional topics of elastic and diffractive scattering, the workshop has had a variety of interesting talks coming under the broad umbrella of ``Recent Advances in Hadron Physics.`` These have included review talks on lattice gauge theory, techniques for high-order perturbative QCD calculations, strong interaction effective field theories, the current status of QED and the construction of theories beyond the Standard Model. While the author briefly describes some topics covered, a ``review of reviews`` is in no way a substitute for the original reviews which also appear, of course, in this same volume. Among the more traditional topics covered are: BFKL physics -- higher-order corrections and jet cross-sections; unitarity and eikonal screening -- mainly in deep-inelastic diffraction but also in soft diffraction; elastic scattering phenomenology -- including real parts, the pomeron intercept and small-t oscillations. Also discussed is the role of factorization, i.e. both Regge pole factorization and perturbative QCD factorization theorems in the definition of a pomeron structure function and in the formulation of a parton model description of diffractive hard physics. The author focuses on one gluon versus two gluons as illustrating the …
Date: September 17, 1997
Creator: White, A.R.
System: The UNT Digital Library
Phototransformation of Polycyclic Aromatic Hydrocarbons (PAHs) on a Non-Semi Conductive Surface Such as Silica (open access)

Phototransformation of Polycyclic Aromatic Hydrocarbons (PAHs) on a Non-Semi Conductive Surface Such as Silica

Polycyclic aromatic hydrocarbons (PAH), by products of fossil fuel production and consumption, constitute a large class of environmental pollutants. These toxic and sometimes carcinogenic compounds are also found in coal tar and fly ash. When released into the air, they can be sorbed onto particulates present in the atmosphere where they find their way into soil and ground water upon being washed by rain. During their residence time in the environment, PAHs will be exposed to solar radiation and may undergo phototransformation to other products. Thus, light induced photodegradation of PM`s at the solid/air interfaces can play a significant role in their depletion. Light-induced processes have been claimed to enhance transformation of these PM`s in the environment. However, detailed studies on the nature and identities of photoproducts formed during the transformation of these compounds on solid surfaces is scarce. Since insulators such as silica, alumina,silicoaluminates and calcium carbonate are believed to constitute up 20-30% of inorganic particulates present in the atmosphere, they serve as environmentally relevant model surfaces to study the photophysical and photochemical behavior of PM`s. Although photochemistry of organic compounds adsorbed on solid surfaces has received much attention in recent years, the specific properties of the interface which …
Date: September 16, 1997
Creator: Dabestani, R., Sigman, M.E.
System: The UNT Digital Library
Systematic approach to analyzing and reducing aerodynamic drag of heavy vehicles (open access)

Systematic approach to analyzing and reducing aerodynamic drag of heavy vehicles

This paper presents an approach for reducing aerodynamic drag of heavy vehicles by systematically analyzing trailer components using existing computational tools and moving on to the analyses of integrated tractor-trailers using advanced computational tools. Experimental verification and validation are also an important part of this approach. The project is currently in the development phase while we are in the process of constructing a Multi-Year Program Plan. Projects I and 2 as described in this paper are the anticipated project direction. Also included are results from past and current related activities by the project participants which demonstrate the analysis approach.
Date: September 16, 1997
Creator: McCallen, R.; Browand, F.; Leonard, A. & Rutledge, W.
System: The UNT Digital Library
Zephyr: a secure internet-based process to streamline engineering (open access)

Zephyr: a secure internet-based process to streamline engineering

None
Date: September 16, 1997
Creator: Jordan, C. W., LLNL
System: The UNT Digital Library
Automated leak test systems (open access)

Automated leak test systems

An automated leak test system for tritium shipping containers has been developed at Westinghouse Savannah River Co. (WSRC). The leak detection system employs a computer controlled helium detector which allows an operator to enter key information when prompted. The software for controlling the tests and the equipment apparatus were both designed and manufactured at the Savannah River Technology Center within WSRC. Recertification Test: Every twelve months, the pressure vessel portion of the shipping container itself must undergo a rigorous recertification leak test. After an empty pressure vessel (shipping container) is assembled, it is placed into one of six stainless steel belljars for helium leak testing. The belljars are fashioned in row much the same as assembly line arrangement. Post-load Test: A post-load leak test is performed upon reservoirs that have been filled with tritium and placed inside the shipping containers mentioned above. These leak tests are performed by a rate-of-rise method where the area around the shipping container seals is evacuated, valved off from the vacuum pump, and then the vacuum pressure is monitored over a two-minute period. The Post Load Leak Test is a quality verification test to ensure that the shipping container has been correctly assembled. 2 figs.
Date: September 15, 1997
Creator: Cordaro, J. V.; Thompson, W. D. & Reeves, G.
System: The UNT Digital Library
Nonlinear Rayleigh-Taylor and Richtmyer-Meshkov Mixing Experiments at Nova (open access)

Nonlinear Rayleigh-Taylor and Richtmyer-Meshkov Mixing Experiments at Nova

The evolution of the Rayleigh-Taylor (RT) and Richtmyer-Meshkov (RM) instabilities in the nonlinear regime of growth was investigated in indirect-drive experiments on the Nova laser. The RT experiments investigated the evolution of both single- and multimode perturbations at an embedded interface, isolated from the effects of ablation. This ``classical`` geometry allows short wavelength ({lambda} {approximately} 10-20 {micro}m) perturbations to grow strongly, in marked contrast to prior results at an ablation front. The RM experiments studied singly- and doubly-shocked perturbed interfaces in both face-on and side-on geometries. (U)
Date: September 15, 1997
Creator: Budil, K. S.; Remington, B. A.; Weber, S. V.; Farley, D.R.; Murray, S. & Peyser, T.A.
System: The UNT Digital Library
Different understanding: science through the eyes of visual thinkers (open access)

Different understanding: science through the eyes of visual thinkers

The objective of this emergent study was to follow the cognitive and creative processes demonstrated by five art student participants as they integrated a developing knowledge of big science, as practiced at the Department of Energy`s Lawrence Livermore National Laboratory, into a personal and idiosyncratic visual, graphical, or multimedia product. The non-scientist participants involved in this process attended design classes sponsored by the Laboratory at the Art Center College of Design in California. The learning experience itself, and how the students arrived at their product, were the focus of the class and the research. The study was emergent in that we found no applicable literature on the use of art to portray a cognitive understanding of science. This lack of literature led us to the foundation literature on creativity and to the corpus of literature on public understanding of science. We believe that this study contributes to the literature on science education, art education, cognitive change, and public understanding of science. 20 refs., 11 figs.
Date: September 11, 1997
Creator: Sesko, S.C. & Marchant, M.
System: The UNT Digital Library
Comparison of neutral gas models for divertor plasmas (open access)

Comparison of neutral gas models for divertor plasmas

None
Date: September 10, 1997
Creator: Rensink, M. E., LLNL
System: The UNT Digital Library