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Current results of the tandem mirror experiment (open access)

Current results of the tandem mirror experiment

The basic operating characteristics of the Tandem Mirror Experiment, (TMX) at the Lawrence Livermore Laboratory in the USA have been established. Tandem-mirror plasmas have been produced using neutral-beam-fueled end plugs and a gas-fueled center cell. An axial potential well between the end plugs has been measured. There is direct evidence that this potential well enhances the axial confinement of the center-cell ions. The observed densities and loss currents are consistent with preliminary studies of the particle sources and losses near the magnetic axis. The observed confinement is consistent with theory when plasma fluctuations are low. When the requirement of drift-cyclotron loss-cone mode stability is violated, the plasma fluctuations degrade the center-cell confinement.
Date: April 9, 1980
Creator: Drake, R. P.
System: The UNT Digital Library
Dependence of laser-plasma interaction physics on laser wavelength and plasma scalelength (open access)

Dependence of laser-plasma interaction physics on laser wavelength and plasma scalelength

We discuss the dependence of many features of laser-plasma interaction physics on both the laser wavelength and plasma dimensions. Experimental results that are presented include absorption, stimulated Brillouin scattering, suprathermal electron production, and optical signatures of the two plasmon decay and stimulated Raman instabilities. While the experiments show beneficial effects of decreasing laser wavelength on the coupling physics, the mix and efficiency of the various interaction processes is shown to be strongly dependent on the size of the underdense plasma. 42 refs., 20 figs., 5 tabs.
Date: April 9, 1984
Creator: Campbell, E. M.
System: The UNT Digital Library
Advanced multi-dimensional method for structural and hydrodynamic analyses of LMFBR piping systems (open access)

Advanced multi-dimensional method for structural and hydrodynamic analyses of LMFBR piping systems

Maintaining the structural integrity of the piping system of Liquid Metal Fast Breeder Reactors (LMFBRs) is essential to the safe operation of the reactor and steam supply systems. In the safety analysis various transient loads can be imposed on the piping systems, which may pose threats to the integrity of the piping structure. These transient loads can be classified into two categories. The first represents dynamic loads resulting from the hydrodynamic pressure-wave propagation or seismic events. The second represents static or quasi-dynamic loads generated by thermal wave propagation, normal operation transient, or creep phenomena. At Argonne National Laboratory, a multi-dimensional method has been developed for the integrated analysis of piping systems under these transient loading conditions. It utilizes a 2-D implicit finite-difference hydrodynamics in conjunction with a 3-D explicit finite-element structural analysis.
Date: April 9, 1985
Creator: Wang, C. Y. & Zeuch, W. R.
System: The UNT Digital Library
Micro-tomography using synchrotron radiation (open access)

Micro-tomography using synchrotron radiation

This paper discusses the results of recent experiments at Stanford Synchrotron Radiation Laboratory (SSRL) and Hamburger Synchrotronstrahlungslabor (HASYLAB) which were designed to explore the feasibility of using synchrotron radiation in high-resolution, computerized, critical-absorption tomography. The results demonstrate that it is possible, using absorption-edge differencing, to identify adjacent elements in the periodic table with high sensitivity. Furthermore, by using the fine structure in the absorption spectra, it is possible to distinguish between regions of different chemical states. Methods of using synchrotron radiation for high-resolution, three-dimensional chemical-state mapping in small samples are discussed.
Date: April 9, 1986
Creator: Johnson, Q.C.; Kinney, J.H.; Bonse, U.; Nichols, M.C.; Nusshardt, R. & Brase, J.M.
System: The UNT Digital Library
Powder handling for automated fuel processing (open access)

Powder handling for automated fuel processing

Installation of the Secure Automated Fabrication (SAF) line has been completed. It is located in the Fuel Cycle Plant (FCP) at the Department of Energy's (DOE) Hanford site near Richland, Washington. The SAF line was designed to fabricate advanced reactor fuel pellets and assemble fuel pins by automated, remote operation. This paper describes powder handling equipment and techniques utilized for automated powder processing and powder conditioning systems in this line. 9 figs.
Date: April 9, 1989
Creator: Frederickson, J.R.; Eschenbaum, R.C. & Goldmann, L.H.
System: The UNT Digital Library
Computing and data handling recent experiences at Fermilab and SLAC (open access)

Computing and data handling recent experiences at Fermilab and SLAC

Computing has become evermore central to the doing of high energy physics. There are now major second and third generation experiments for which the largest single cost is computing. At the same time the availability of cheap'' computing has made possible experiments which were previously considered infeasible. The result of this trend has been an explosion of computing and computing needs. I will review here the magnitude of the problem, as seen at Fermilab and SLAC, and the present methods for dealing with it. I will then undertake the dangerous assignment of projecting the needs and solutions forthcoming in the next few years at both laboratories. I will concentrate on the offline'' problem; the process of turning terabytes of data tapes into pages of physics journals. 5 refs., 4 figs., 4 tabs.
Date: April 9, 1990
Creator: Cooper, P. S.
System: The UNT Digital Library
Vacuum design for a superconducting mini-collider (open access)

Vacuum design for a superconducting mini-collider

The phi factory (Superconducting Mini-Collider or SMC) proposed for construction at UCLA is a single storage ring with circulating currents of 2 A each of electrons and positrons. The small circumference exacerbates the difficulties of handling the gas load due to photo-desorption from the chamber walls. We analyze the vacuum system for the phi factory to specify design choices. 7 refs., 6 figs., 1 tab.
Date: April 9, 1991
Creator: Barletta, W.A. (Lawrence Livermore National Lab., CA (USA)) & Monteiro, S. (Moorpark Coll., CA (USA))
System: The UNT Digital Library
The superfluid Stirling refrigerator, a new method for cooling below 0.5 K (open access)

The superfluid Stirling refrigerator, a new method for cooling below 0.5 K

A new subkelvin refrigerator, the superfluid Stirling cycle refrigerator, uses a working fluid of {sup 3}He-{sup 4}He mixture in a Stirling cycle. The thermodynamically active components of the mixture are the {sup 3}He, which behaves like a Boltzman gas, and the phonon-roton gas in the {sup 4}He. The superfluid component of the liquid is inert. Two refrigerators have been built and temperatures of 340 mK have been achieved.
Date: April 9, 1993
Creator: Brisson, J. G.; Kotsubo, V. & Swift, G. W.
System: The UNT Digital Library
The superfluid Stirling refrigerator, a new method for cooling below 0. 5 K (open access)

The superfluid Stirling refrigerator, a new method for cooling below 0. 5 K

A new subkelvin refrigerator, the superfluid Stirling cycle refrigerator, uses a working fluid of [sup 3]He-[sup 4]He mixture in a Stirling cycle. The thermodynamically active components of the mixture are the [sup 3]He, which behaves like a Boltzman gas, and the phonon-roton gas in the [sup 4]He. The superfluid component of the liquid is inert. Two refrigerators have been built and temperatures of 340 mK have been achieved.
Date: April 9, 1993
Creator: Brisson, J.G.; Kotsubo, V. & Swift, G.W.
System: The UNT Digital Library
[Art Smart article, April 9, 1995] (open access)

[Art Smart article, April 9, 1995]

An article from the Fort Worth Star-Telegram written by Clara Herrera. The article covers Brandon Lewis and other students in art classes and the logistics behind what courses are available to them.
Date: April 9, 1995
Creator: Herrera, Clara G.
System: The UNT Digital Library
[UNT graduate students take center stage, April 9, 1995] (open access)

[UNT graduate students take center stage, April 9, 1995]

An article written by April M. Washington for the Denton Record-Chronicle that covers two graduate students from UNT, Bader Alruwais and Matthew Mailman. Alruwais received the Prince Bandar ibn Sultan Annual Award for Cultural and Scientific Research and Mailman is conducting a recital performance.
Date: April 9, 1995
Creator: Washington, April M.
System: The UNT Digital Library
LANL`s mobile nondestructive assay and examination systems for radioactive wastes (open access)

LANL`s mobile nondestructive assay and examination systems for radioactive wastes

The ability to accurately and rapidly measure nuclear material within drums and examine their contents without having to unpack the drums saves time, reduces characterization costs and minimizes radiation exposure. Over the past two years, Los Alamos National Laboratory (LANL) has developed and fielded a suite of mobile nondestructive assay and examination systems for use primarily on its own transuranic (TRU) waste but that also have application to low level, mixed and hazardous wastes. It has become obvious that systems like these are generally useful and have applications at other Department of Energy (DOE) production and environmental technology sites. Mobile capabilities present a potential cost savings where waste drums have to be transported to a fixed NDA facility. In other cases they fill a void where there is no fixed facility available because construction costs are prohibitive (as in the case of small quantity sites) or the available facilities may not meet current or evolving safety standards. Rather than bringing waste to a facility to be characterized, one can bring the characterization capability to the waste. The three systems described are: (1) mobile radiography system; (2) mobile segmented/tomographic gamma scanner; and (3) mobile passive/active neutron assay system.
Date: April 9, 1996
Creator: Taggart, D.P. Betts, S.E. & Vigil, J.J.
System: The UNT Digital Library
Reducing nuclear danger through intergovernmental technical exchanges on nuclear materials safety management (open access)

Reducing nuclear danger through intergovernmental technical exchanges on nuclear materials safety management

The United States and Russia are dismantling nuclear weapons and generating hundreds of tons of excess plutonium and high enriched uranium fissile nuclear materials that require disposition. The U.S. Department of Energy and Russian Minatom organizations.are planning and implementing safe, secure storage and disposition operations for these materials in numerous facilities. This provides a new opportunity for technical exchanges between Russian and Western scientists that can establish an improved and sustained common safety culture for handling these materials. An initiative that develops and uses personal relationships and joint projects among Russian and Western participants involved in fissile nuclear materials safety management contributes to improving nuclear materials nonproliferation and to making a safer world. Technical exchanges and workshops are being used to systematically identify opportunities in the nuclear fissile materials facilities to improve and ensure the safety of workers, the public, and the environment.
Date: April 9, 1997
Creator: Jardine, L. J.; Peddicord, K. L.; Witmer, F. E.; Krumpe, P. F.; Lazarev, L. & Moshkov, M.
System: The UNT Digital Library
Energy and momentum conserving algorithms for rigid body contact (open access)

Energy and momentum conserving algorithms for rigid body contact

Energy-momentum conserving methods are developed for rigid body dynamics with contact. Because these methods are unconditionally stable, they are not time step dependent and, hence, are well suited for incorporation into structural mechanics finite element codes. Both penalty and Lagrange multiplier methods are developed herein and are the extension of the energy-momentum conserving integration schemes for rigid bodies given by Simo and Wong [1].
Date: April 9, 1998
Creator: Puso, Michael A. & Zywicz, Edward
System: The UNT Digital Library
EUV optical design for 100 nm CD imaging system (open access)

EUV optical design for 100 nm CD imaging system

The imaging specifications for extreme ultraviolet lithography (EUVL) projection optics parallel those of other optical lithographies. Specifications are scaled to reflect the 100 nm critical dimension for the first generation EUVL systems. The design being fabricated for the Engineering Test Stand, an EUVL alpha tool, consists of a condenser with six channels to provide an effective partial coherence factor of 0.7. The camera contains four mirrors; three of the mirrors are aspheres and the fourth is spherical. The design of the optical package has been constrained so that the angles of incidence and the variations in the angle of incidence of all rays allow for uniform multilayer coatings. The multilayers introduce a slight shift in image position and magnification. We have shown that a system aligned with visible light is also aligned at 13.4 nm. Each mirror must be fabricated with an RMS figure error of less than 0.25 nm and better than 0.2 nm RMS roughness. Optical surfaces that exceed each of these specifications individually have been fabricated. The success of EUVL requires that these specifications be met simultaneously.
Date: April 9, 1998
Creator: Sweeney, D.W.; Hudyma, R.; Chapman, H.B. & Shafer, D.
System: The UNT Digital Library
Architecture for Teraflop Visualization (open access)

Architecture for Teraflop Visualization

Sandia Laboratories' computational scientists are addressing a very important question: How do we get insight from the human combined with the computer-generated information? The answer inevitably leads to using scientific visualization. Going one technology leap further is teraflop visualization, where the computing model and interactive graphics are an integral whole to provide computing for insight. In order to implement our teraflop visualization architecture, all hardware installed or software coded will be based on open modules and dynamic extensibility principles. We will illustrate these concepts with examples in our three main research areas: (1) authoring content (the computer), (2) enhancing precision and resolution (the human), and (3) adding behaviors (the physics).
Date: April 9, 1999
Creator: Breckenridge, A.R. & Haynes, R.A.
System: The UNT Digital Library
A dynamic object-oriented architecture approach to ecosystem modeling and simulation. (open access)

A dynamic object-oriented architecture approach to ecosystem modeling and simulation.

Modeling and simulation in support of adaptive ecosystem management can be better accomplished through a dynamic, integrated, and flexible approach that incorporates scientific and technological components into a comprehensive ecosystem-modeling framework. The Integrated Dynamic Landscape Analysis and Modeling System (IDLAMS) integrates ecological models and decision support techniques, through a geographic information system (GIS)-based framework. The Strategic Environmental Research and Development Program (SERDP) sponsored the development of IDLAMS. Initially built upon a GIS framework, IDLAMS is migrating to an object-oriented (OO) architectural framework. An object-oriented architecture is more flexible and modular. It allows disparate applications and dynamic models to be integrated in a manner that minimizes (or eliminates) the need to rework or recreate the system as new models are added to the suite. In addition, an object-oriented design makes it easier to provide run-time feedback among models, thereby making it a more dynamic tool for exploring and providing insight into the interactions among ecosystem processes. Finally, an object-oriented design encourages the reuse of existing technology because OO-IDLAMS is able to integrate disparate models, databases, or applications executed in their native languages. Reuse is also accomplished through a structured approach to building a consistent and reusable object library. This reusability can …
Date: April 9, 1999
Creator: Dolph, J. E.; Majerus, K. A.; Sydelko, P. J. & Taxon, T. N.
System: The UNT Digital Library
Emerging high technology fields and thoughts on reshaping the engineering curriculum. (open access)

Emerging high technology fields and thoughts on reshaping the engineering curriculum.

In the early part of this workshop, I believe Dr. Bergles made a statement indicating that certain schools in America are planning to take the traditional heat transfer and fluid mechanics courses out of their curriculum and that some may have already done so. That statement created some excitement, and I did respond to that in some fashion and make some suggestions. Then Dr. Bergles said ''well maybe these matters should be included in a separate discussion period,'' which is this forum. Because I am working at the Advanced Photon Source at Argonne National Laboratory, I have the opportunity to witness the type of research being done in high technology areas today with the most advanced x-rays, which gives me some sort of advantage for telling you what I see as future research directions. Hence, I would like to reflect on all of this along a different avenue, and really my presentation will stress the educational side: essentially engineering education and what our role should be at the universities in teaching the next generation of students coming in and also what our role should be in retraining researchers for the demands of the emerging fields and markets.
Date: April 9, 1999
Creator: Kuzay, T. M.
System: The UNT Digital Library
Implications of a new induction core materials and coatings for high power induction accelerators (open access)

Implications of a new induction core materials and coatings for high power induction accelerators

Two recent developments enable induction accelerators to achieve better and more consistent performance with higher efficiency. First, better and more consistent performance is achieved with insulating coatings that allow magnetic cores to be annealed after winding. Second, losses are reduced by a factor of 2-3 with nanocrystalline alloys, while the flux swing is only slightly reduced to 2.0 T compared with 2.3 T with economical amorphous alloys. One metric for selecting between the alloys is the cost-of-electricity, COE. A systems code optimizes an accelerator and compares the COE for higher flux-swing amorphous and higher-efficiency nanocrystalline materials and for several variations in assumptions.
Date: April 9, 1999
Creator: Molvic, A. W.; Meier, W. R.; Moir, R. W. & Faltens, A.
System: The UNT Digital Library
Induction time effects in pulse combustors (open access)

Induction time effects in pulse combustors

Combustion systems that take advantage of a periodic combustion process have many advantages over conventional systems. Their rate of heat transfer is greatly enhanced and their pollutant emissions are lower. They draw in their own supply of fuel and air and they are self-venting. They have few moving parts. The most common type of pulse combustor is based on a Helmholtz resonator - a burning cycle drives a resonant pressure wave, which in turn enhances the rate of combustion, resulting in a self-sustaining, large-scale oscillation. Although the basic physical mechanisms controlling such a process were explained by Rayleigh over a century ago, a full understanding of the operation of a pulse combustor still does not exist. The dominant processes in such a system--combustion, turbulent fluid dynamics, acoustics--are highly coupled and interact nonlinearly, which has reduced the design process to a costly and inefficient trial-and-error procedure. Several recent numerical and experimental studies, however, have been focused towards a better understanding of the basic underlying physics. Barr et al. [l] have elucidated the relative roles of the time scales governing the energy release, the turbulent mixing, and the acoustics. Keller et al. [5] have demonstrated the importance of the phase relation between …
Date: April 9, 1999
Creator: Bell, J B; Marcus, D L & Pember, R B
System: The UNT Digital Library
New Mexico's Pioneering Steps in Commercializing Solar Power (open access)

New Mexico's Pioneering Steps in Commercializing Solar Power

Over the past two years, New Mexico has been engaged in a significant new approach to implement large purchases of solar power. This effort followed a regulatory process that treated solar power generation similar to conventional generation obtained by an investor-owned utility under the regulation of a public utility commission. In 1997, Public Service Company of New Mexico (PNM) gained approval to purchase power from a 100-MW combustion turbine facility that would be owned and operated by a wholesale generator. At the same time it issued the approval, and following discussions with the utility, the New Mexico Public Utility Commission (NMPUC) also required PNM to issue a request for proposal for a 5-MW central station solar facility, a major step for solar technologies in the state, in what would be the world's largest of its technology type. In cooperation with the staff of the NMPUC, PNM reviewed the proposals received, and Applied Power Corporation was selected for the photovoltaic portion of the proposed plan; retaining ownership of the plant, assuming the risks connected with the technology, and operating the plant in exchange for a power purchase agreement in a first-of-its-kind contract for photovoltaics. During the NMPUC hearings, various parties raised …
Date: April 9, 1999
Creator: Hill, R.R.
System: The UNT Digital Library
[New York Times National Report, April 9, 1999] (open access)

[New York Times National Report, April 9, 1999]

An article in The New York Times National Report written by Richard L. Berke about the conversation around gay issues in Texas. Featured are Governor George Bush's views on gay issues and Charles C. Francis' approval of Bush as well as others in the Republican Party who have spoken on the issue.
Date: April 9, 1999
Creator: Berke, Richard L.
System: The UNT Digital Library
Optical Spectroscopy Measurements of Shock Waves Driven by Intense Z-Pinch Radiation (open access)

Optical Spectroscopy Measurements of Shock Waves Driven by Intense Z-Pinch Radiation

Z-pinches created using the Z accelerator generate {approximately}220 TW, 1.7 MJ radiation pulses that heat large ({approximately}10 cm{sup 3}) hohlraums to 100-150 eV temperatures for times of order 10 nsec. We are performing experiments exploiting this intense radiation to drive shock waves for equation of state studies. The shock pressures are typically 1-10 Mbar with 10 nsec duration in 6-mm-diameter samples. In this paper we demonstrate the ability to perform optical spectroscopy measurements on shocked samples located in close proximity to the z-pinch. These experiments are particularly well suited to optical spectroscopy measurements because of the relatively large sample size and long duration. The optical emission is collected using fiber optics and recorded with a streaked spectrograph. Other diagnostics include VISAR and active shock breakout measurements of the shocked sample and a suite of diagnostics that characterize the radiation drive. Our near term goal is to use the spectral emission to obtain the temperature of the shocked material. Longer term objectives include the examination of deviations of the spectrum from blackbody, line emission from lower density regions, determination of kinetic processes in molecular systems, evaluation of phase transitions such as the onset of metalization in transparent materials, and characterization of …
Date: April 9, 1999
Creator: Asay, J.; Bailey, J. E.; Carlson, A. L.; Chandler, G. A.; Hall, C. A.; Hanson, D. et al.
System: The UNT Digital Library
A problem of stand-off energy sources for MTF (open access)

A problem of stand-off energy sources for MTF

Fusion devices based on the adiabatic (or shock) compression of the plasma by electromagnetically driven liner need specific energy sources capable of delivering a high current (~10 MA) in the pulses 0.1 - 1 microsecond long. In the present experimental facilities, the plasma load is situated very close to the pulse-power energy source. In the future fusion devices, one would have to place a plasma load at a considerable distance from the energy source (to avoid strong neutron and thermo-mechanical damage to the source). Several versions of the stand-off energy sources are considered. All are based on the idea of an "assembly" - an object where the plasma load is nested and which contains all necessary circuitry that allows conversion of the energy delivered to the assembly into the magnetic energy. Such "assemblies" will be dropped (or inserted) into the reaction chamber at a desired rate and energized by a stand-off energy source. Four specific concepts have been mentioned.
Date: April 9, 1999
Creator: Ryutov, D. D.
System: The UNT Digital Library