Regimes of improved confinement and stability in DIII-D obtained through current profile modifications (open access)

Regimes of improved confinement and stability in DIII-D obtained through current profile modifications

Several regimes of improved confinement and stability have been obtained in recent experiments in the DIII-D tokamak by dynamically varying the toroidal current density profile to transiently produce a poloidal magnetic field profile with more favorable confinement and stability properties. A very peaked current density profile with high plasma internal inductance, [ell][sub i], is produced either by a rapid change in the plasma poloidal cross section or by a rapid change in the total plasma current. Values of thermal energy confinement times nearly 1.8 times the JET/DIII-D ELM-free H-mode thermal confinement scaling are obtained. The confinement enhancement factor over the ITER89-P L-mode confinement scaling, H, is as high as 3. Normalized toroidal beta, [beta][sub N], greater than 6%-m-T/MA and values of the product [beta][sub N]H greater than 15 have also been obtained. Both the confinement and the maximum achievable [beta] vary with [ell][sub i] and decrease as the current profile relaxes. For strongly shaped H-mode discharges, in addition to the current density profile peakedness, as measured by [ell][sub i] other current profile parameters, such as its distribution near the edge region, may also affect the confinement enhancement.
Date: September 1, 1992
Creator: Lao, L. L.; Ferron, J. R.; Taylor, T. S.; Chan, V. S.; Osborne, T. H.; Burrell, K. H. et al.
System: The UNT Digital Library
Magnetic decoupling in sputtered Fe/Si superlattices and multilayers (open access)

Magnetic decoupling in sputtered Fe/Si superlattices and multilayers

A series of sputtered Fe/Si superlattices was grown to study the magnetic coupling between ferromagnetic Fe layers (30[Angstrom] thick) for Si spacer-layer thicknesses (t[sub Si]) between 10 and 40[Angstrom]. The material is ferromagnetically coupled for t[sub Si]<13[Angstrom] and antiferromagneticly coupled for 13[Angstrom]<t[sub Si]<17[Angstrom]. For t[sub Si]>17[Angstrom] the magnetic Fe layers are uncoupled. X-ray analysis indicates that the system is well layered, but that the crystal structure remains coherent only for t[sub Si]<17[Angstrom]. These results, along with our Moessbauer investigation, strongly suggest that the Si layer is crystalline for t[sub Si]<17[Angstrom], and is iron silicide in nature. For thicker spacers, Si becomes amorphous. We propose a model of the layering that is consistent with the known properties of Fe-silicide.
Date: September 1, 1992
Creator: Fullerton, E. E.; Mattson, J. E.; Lee, S. R.; Sowers, C. H.; Huang, Y. Y.; Felcher, G. et al.
System: The UNT Digital Library
Development of the GA-4 and GA-9 legal weight spent fuel casks (open access)

Development of the GA-4 and GA-9 legal weight spent fuel casks

GA is nearing the completion of the final design of two legal weight truck spent fuel shipping casks, the GA-4 Cask for PWR fuel and the GA-9 Cask for BWR fuel. GA is developing the casks under contract to the US Department of Energy (DOE) Field Office, Idaho, as part of the Office of Civilian Radioactive Waste Management (OCRWM) Cask Systems Development Program (CSDP). The casks will transport intact spent fuel assemblies fro commercial nuclear reactors sites to a monitored retrievable storage facility or a permanent repository. The DOE initiated the Cask Systems Development Program in response to the Nuclear Waste Policy Act of 1982 which made DOE responsible for managing the program for permanent disposal of spent nuclear fuel and high-level waste. This paper describes developmental and design verification testing programs, and the present status of the GA-4 and GA-9 Cask designs.
Date: September 1, 1992
Creator: Grenier, R. M.; Meyer, R. J. & Mings, W. J.
System: The UNT Digital Library
The energy saving potential of precooling incoming outdoor air by indirect evaporative cooling (open access)

The energy saving potential of precooling incoming outdoor air by indirect evaporative cooling

This paper investigates the energy saving potentials of using indirect evaporative coolers to precool incoming outdoor air as the first stage of a standard cooling system. For dry and moderately humid locations, either exhaust room air or outdoor air can be used as the secondary air to the indirect evaporative precooler with similar energy savings. Under these conditions, the use of outdoor air is recommended due to the simplicity in installing the duct system. For humid locations, the use of exhaust room air is recommended because the precooling capacity and energy savings will be greatly increased. For locations with short cooling seasons, the use of indirect evaporative coolers for precooling may not be worthwhile. The paper also gives some simplified indices for easily predicting the precooling capacity, energy savings and water consumption of an indirect evaporative precooler. These indices can be used for cooling systems with continuous operation, but further work is needed to determine whether the same indices are also suitable for cooling systems with intermittent operations.
Date: September 1, 1992
Creator: Chen, P.; Qin, H.; Huang, Y. J.; Wu, H. & Blumstein, C.
System: The UNT Digital Library
Radionuclide characterization at US commercial light-water reactors for decommissioning assessment: Distributions, inventories, and waste disposal considerations (open access)

Radionuclide characterization at US commercial light-water reactors for decommissioning assessment: Distributions, inventories, and waste disposal considerations

A continuing research program, conducted by Pacific Northwest Laboratory for the US Nuclear Regulatory Commission, characterizing radionuclide concentrations associated with US light-water reactors has been conducted for more than a decade. The research initially focused upon sampling and analytical measurements for the purpose of establishing radionuclide distributions and inventories for decommissioning assessment, since very little empirical data existed. The initial phase of the research program examined radionuclide concentrations and distributions external to the reactor vessel at seven US light water reactors. Later stages of the research program have examined the radionuclide distributions in the highly radioactive reactor internals and fuel assembly. Most recently, the research program is determining radionuclide concentrations in these highly radioactive components and comparing empirical results with those derived from the several nonempirical methodologies employed to estimate radionuclide inventories for disposal classification. The results of the research program to date are summarized, and their implications and significance for the decommissioning process are noted.
Date: September 1, 1992
Creator: Abel, K. H.; Robertson, D. E. & Thomas, C. W.
System: The UNT Digital Library
Fast wave current drive system design for DIII-D (open access)

Fast wave current drive system design for DIII-D

DIII-D has a major effort underway to develop the physics and technology of fast wave electron heating and current drive in conjunction with electron cyclotron heating. The present system consists of a four strap antenna driven by one 2 MW transmitter in the 32--60 MHz band. Experiments have been successful in demonstrating the physics of heating and current drive. In order to validate fast wave current drive for future machines a greater power capability is necessary to drive all of the plasma current. Advanced tokamak modeling for DIII-D has indicated that this goal can be met for plasma configurations of interest (i.e. high [beta] VH-mode discharges) with 8 MW of transmitter fast wave capability. It is proposed that four transmitters drive fast wave antennas at three locations in DIII-D to provide the power for current drive and current profile modification. As the next step in acquiring this capability, two modular four strap antennas are in design and the procurement of a high power transmitter in the 30--120 MHz range is in progress. Additionally, innovations in the technology are being investigated, such as the use of a coupled combine antenna to reduce the number of required feedthroughs and to provide for …
Date: September 1, 1992
Creator: deGrassie, J. S.; Callis, R.; Lin-Liu, Y. R.; Moeller, C..; Petty, C. C.; Phelps, D. R. et al.
System: The UNT Digital Library
Software engineering: What do experiments need (open access)

Software engineering: What do experiments need

This paper will review the use of software engineering in High Energy Physics experiments and will suggest ways in which that use will change significantly in the future. In Principle, experiments do not need software engineering. We can verify this by looking at a long series of experiments that have succeeded without it. Some experiments that have tried to apply formal engineering methods have given them up before the software was complete. Future experiments, however, face many new challenges in the larger data samples, larger and more distributed collaborations and longer time scales. In addition, new tools are available to aid in the development of complex software systems. It is appropriate, therefore, to examine whether there is now a better match between software engineering and the needs of experiments.
Date: September 1, 1992
Creator: Loken, S.C.
System: The UNT Digital Library
PEP 2: SLAC-based Asymmetric B Factory (open access)

PEP 2: SLAC-based Asymmetric B Factory

The proposal for upgrading the existing PEP collider at SLAC to enable the copious production of boosted B mesons is the result of several years of collaborative study by groups representing LBL, LLNL and SLAC. The PEP II design has evolved in a considered fashion from its initial conceptualization to a very advanced level of understanding, well-substantiated by R D results on the key design issues. We describe the proposed upgrade, review the early conceptual decisions, outline the significant remaining questions, and briefly describe current results from the ongoing R D effort which have shown these questions to be tractable and the initial concepts to be sound.
Date: September 1, 1992
Creator: Fieguth, T.
System: The UNT Digital Library
High power photon beamline elements in the LBL/SSRL/EXXON Beamline VI (open access)

High power photon beamline elements in the LBL/SSRL/EXXON Beamline VI

Beamline VI is a wiggler-based, multi-kilowatt, intense synchrotron radiation beamline installed SPEAR. The thermal design parameters for this beamline are presented and then design considerations and construction descriptions are given for many of the high-power photon beamline elements.
Date: September 1, 1992
Creator: Hoyer, E.
System: The UNT Digital Library
Status of state and local adoption of energy standards for new commercial buildings (open access)

Status of state and local adoption of energy standards for new commercial buildings

This paper presents a summary of building energy standards adoption by state and major local governments and how the standards apply to new commercial buildings. Numerous public and private sector agencies and organizations develop energy standards and codes for commercial buildings. These documents serve, among others, state and local legislators and regulators who are interested in requiring their use to reduce the energy consumption of new commercial buildings. Through adoption or adaptation of these documents by state or local governments, minimum acceptable design and construction criteria for new commercial buildings are established in law. The energy standard or code adopted, or used as a basis for a state developed standard, may be any one of a number of documents. The authority of the state to regulate construction may apply throughout the entire state, only to a few types of buildings, or may be absent, in which case local government has regulatory authority. The means of adoption may be by legislation, regulation, municipal code, or other legal vehicle. At the present time there are widespread differences in the energy standards adopted by state and local government and the application of these standards to new commercial buildings.
Date: September 1, 1992
Creator: Boulin, J.J. (USDOE, Washington, DC (United States)) & Conover, D.R. (Pacific Northwest Lab., Richland, WA (United States))
System: The UNT Digital Library
Self-amplified spontaneous emission for short wavelength coherent radiation (open access)

Self-amplified spontaneous emission for short wavelength coherent radiation

We review the recent progress in our understanding of the self-amplified spontaneous emission (SASE), emphasizing the application to short wavelength generation. Simple formulae are given for the start-up, exponential gain and the saturation of SASE. Accelerator technologies producing high brightness electron beams required for short wavelength SASE are discussed. An example utilizing electron beams from a photocathode-linac system to produce 4nm SASE in the multigigawatt range is presented.
Date: September 1, 1992
Creator: Kim, K. J. & Xie, M.
System: The UNT Digital Library
Direct electron heating and current drive with fast waves in DIII-D (open access)

Direct electron heating and current drive with fast waves in DIII-D

Experiments on the DIII-D tokamak have been performed to evaluate noninductive current drive with direct electron absorption of the fast Alfven wave (FW) in the ion cyclotron range of frequencies. These experiments have employed a 2 MW 60 NM transmitter connected to a four-element toroidally phased array of loop antennas located at the outside midplane of the DIII-D vacuum vessel. Efficient direct electron heating was obtained with (0, [pi], 0, [pi]) antenna phasing; H-mode confinement was obtained with direct electron absorption of the fast wave as the sole source of auxiliary heating. Current drive experiments were performed with (0,[pi]/2,[pi],3[pi]/2) antenna phasing at fast wave power levels up to 1.2 MW. Preheating with 60 GHz ECH was used to increase the single-pass absorption of the fast wave with a directive spectrum. When the fast wave is lunched in the direction that aids the inductively driven current (co-current drive), up to 40% of the 0.4 MA plasma current is sustained noninductively. Counter-current drive strongly affects the sawtoothing behavior, and results in highly peaked electron temperature profiles (T[sub e](0) [approx lt] 6 keV) but much smaller driven currents.
Date: September 1, 1992
Creator: Pinsker, R. I.; Petty, C. C.; Callis, R. W.; Cary, W. P.; Chiu, S. C.; Freeman, R. L. et al.
System: The UNT Digital Library
A knowledge-based system for automated evaluation of energy standards compliance (open access)

A knowledge-based system for automated evaluation of energy standards compliance

It has been estimated that as much as 60% of the energy used to heat, cool, and illuminate buildings could be saved through better design. Although energy standards provide a benchmark against which designers may measure their designs, compliance evaluation often requires tedious calculation. We are building a computer program, the Energy Standards Intelligent Design Tool (ES-IDT), that addresses these issues. The ES-IDT automatically and continually evaluates a building design as it is being developed on a CAD system. If the emerging design begins to deviate from compliance with ASHRAE Standard 90.1-1989, the ES-IDT notifies the architect, indicating which section of the standard was violated and what design decision(s) caused the violation. The ES-IDT also will suggest some design options to improve the energy efficiency of the building.
Date: September 1, 1992
Creator: Quadrel, R.W.; Brambley, M.R. & Stratton, R.C.
System: The UNT Digital Library
Positron annihilation studies of the electronic structure and fermiology of the high-[Tc] superconductors (open access)

Positron annihilation studies of the electronic structure and fermiology of the high-[Tc] superconductors

We discuss the application of the positron annihilation angular correlation (ACAR) spectroscopy for investigating the electronic structure and Fermiology of the high-T[sub c] superconductors, with focus on the YBa[sub 2]Cu[sub 3]O[sub 7] system where most of the experimental and theoretical work has to date been concentrated. Comparisons between measured 2D-ACAR positron spectra and band theory predictions show a remarkable agreement (for the normal state), indicating that the electronic structure and Fermi surface of this material is described reasonably by the conventional picture.
Date: September 1, 1992
Creator: Smedskjaer, L.C. (Argonne National Lab., IL (United States)) & Bansil, A. (Northeastern Univ., Boston, MA (United States). Dept. of Physics)
System: The UNT Digital Library
Experimental study of unsteady laminar and turbulent flame propagation in an enclosure by Rayleigh scattering (open access)

Experimental study of unsteady laminar and turbulent flame propagation in an enclosure by Rayleigh scattering

The Rayleigh scattering technique has been used to investigate the flame structure of unsteady propane/air flames propagating under quiescent and turbulent conditions initiated by three ignition methods: (1) conventional spark plug (2) pulse jet combustion (PJC) and (3) Pre-Chamber ignition (PCI). The Rayleigh signal obtained for the laminar cases are all characterized by a sharp transition associated with the large density change which occurs as leading flame front of the expanding flame kernel crosses the measurement point. This indicates that the local flame structures are independent of the ignition source and may be characterized as flamelets. The maximum burning rates deduced from the pressure records show that PJC and PCI increases the burning rate from two to three times above that of conventional spark ignition. The Rayleigh scattering signal obtained for the turbulent cases are also characterized by sharp transition. The wrinkled laminar flamelet model, therefore, provides a valid description of the flame structures for all these unsteady flames. For a given equivalence ratio, the maximum turbulent burning rate deduced for the three turbulent cases with different ignition sources are similar. This suggests that while PJC and PCI enhances burning rate when conditions in the chamber are quiescent, the enhancement …
Date: September 1, 1992
Creator: Tamai, R. (Consiglio Nazionale della Ricerche, Naples (Italy). Ist. Motori); Shepherd, I.G. & Cheng, R.K. (Lawrence Berkeley Lab., CA (United States))
System: The UNT Digital Library
A massive neutrino in nuclear beta decay (open access)

A massive neutrino in nuclear beta decay

We have continued our studies of the [beta]-spectrum of [sup 14]C using a germanium detector doped with [sup l4]C. There is a feature in the [beta]-spectrum 17 keV below the endpoint which could be explained by the hypothesis that there is a heavy neutrino emitted in the [beta]-decay of [sup 14]C with a mass of 17[plus minus]1 keV and an emission probability of 1.26[plus minus]0.25%. However, we also have performed a high statistics measurement of the inner bremsstrahlung spectrum of [sup 55]Fe and find no indication of the emission of a [sup 17]-keV neutrino. We conclude that the origin of the kink'' that has been observed in some recent beta spectral measurements is not a neutrino.
Date: September 1, 1992
Creator: Norman, E.B.; Chan, Yuen-Dat; Garcia, A.; Lesko, K.T.; Larimer, R.M.; Stokstad, R.G. Sur, B. et al.
System: The UNT Digital Library
An electronic stroll through the global village (open access)

An electronic stroll through the global village

This paper is a semi-random walk through Usenet News, a bulletin board system that exists on the vast Internet computer network. Interaction in such a medium is an interesting hybrid of speech and writing, of monologue and dialogue and sometimes an open shouting match in a crowded room. Those who are intrigued by these matters will be able to see a number of research areas exposed in this frankly anecdotal paper. In addition to being anecdotal, this paper is a work of participatory observation. In fact, I occasionally let it be known that I was observing the sociology and rhetoric of the newsgroups. The natives appeared unimpressed.
Date: September 1, 1992
Creator: Chew, J.
System: The UNT Digital Library
The Energy Saving Potential of Precooling Incoming Outdoor Air by Indirect Evaporative Cooling (open access)

The Energy Saving Potential of Precooling Incoming Outdoor Air by Indirect Evaporative Cooling

This paper investigates the energy saving potentials of using indirect evaporative coolers to precool incoming outdoor air as the first stage of a standard cooling system. For dry and moderately humid locations, either exhaust room air or outdoor air can be used as the secondary air to the indirect evaporative precooler with similar energy savings. Under these conditions, the use of outdoor air is recommended due to the simplicity in installing the duct system. For humid locations, the use of exhaust room air is recommended because the precooling capacity and energy savings will be greatly increased. For locations with short cooling seasons, the use of indirect evaporative coolers for precooling may not be worthwhile. The paper also gives some simplified indices for easily predicting the precooling capacity, energy savings and water consumption of an indirect evaporative precooler. These indices can be used for cooling systems with continuous operation, but further work is needed to determine whether the same indices are also suitable for cooling systems with intermittent operations.
Date: September 1992
Creator: Chen, P.; Qin, H.; Huang, Y. J.; Wu, H. & Blumstein, C.
System: The UNT Digital Library
Current status, research needs, and opportunities in applications of surface processing to transportation and utilities technologies. Proceedings of a December 1991 workshop (open access)

Current status, research needs, and opportunities in applications of surface processing to transportation and utilities technologies. Proceedings of a December 1991 workshop

Goal of surface processing is to develop innovative methods of surface modification and characterization for optimum performance and environmental protection for cost-effective operational lifetimes of systems, materials, and components used in transportation and utilities. These proceedings document the principal discussions and conclusions reached at the workshop; they document chapters about the current status of surface characterization with focus on composition, structure, bonding, and atomic-scale topography of surfaces. Also documented are chapters on the current status of surface modification techniques: electrochemical, plasma-aided, reactive and nonreactive physical vapor deposition, sol-gel coatings, high-energy ion implantation, ion-assisted deposition, organized molecular assemblies, solar energy. Brief chapters in the appendices document basic research in surface science by NSF, Air Force, and DOE. Participants at the workshop were invited to serve on 10 working groups. Separate abstracts were prepared for the data base where appropriate.
Date: September 1, 1992
Creator: Czanderna, A. W. & Landgrebe, A. R.
System: The UNT Digital Library
HippoDraw (open access)

HippoDraw

HippoDraw is a NeXTSTEP application for viewing statistical data. It has several unique features which make viewing data distributions highly interactive. It also incorporates a set of simple drawing tools. HippoDraw is written in Objective-C and uses the Hippoplotamus library package to handle the n-tuples and displays.
Date: September 1, 1992
Creator: Gravina, M. F.; Kunz, P. F. & Rensing, P. E.
System: The UNT Digital Library
UNIX code management and distribution (open access)

UNIX code management and distribution

We describe a code management and distribution system based on tools freely available for the UNIX systems. At the master site, version control is managed with CVS, which is a layer on top of RCS, and distribution is done via NFS mounted file systems. At remote sites, small modifications to CVS provide for interactive transactions with the CVS system at the master site such that remote developers are true peers in the code development process.
Date: September 1992
Creator: Hung, Terry & Kunz, Paul F.
System: The UNT Digital Library
The implications of concurrent increases in temperature and CO{sup 2} concentration for terrestrial C{sup 3} photosynthesis (open access)

The implications of concurrent increases in temperature and CO{sup 2} concentration for terrestrial C{sup 3} photosynthesis

This study utilizes a mechanistic model of lea photosynthesis to examine the potential quantitative significance of the interaction of rising atmospheric. Carbon dioxide concentration (C{sub a}) and temperature on leaf photosynthesis. Predictions are compared to experimental measurements in which plants have been grown either in elevated C{sub a} in the field for extended periods or from seed in controlled environments, to examine the interaction of low temperature with elevated C{sub a}. Three questions addressed were: To what extent will increase in C{sub a} modify the response of leaf photosynthetic CO{sub 2} uptake (A) to temperature; is the decrease in photosynthesis at sub-optimal temperatures predicted for plants grown at elevated C{sub a}, realized in practice? Is photoinhibition accentuated in plants grown in the field at elevated C{sub a} for long-periods.
Date: September 1, 1992
Creator: Long, S. P.; Nie, G. Y.; Drake, B. G.; Hendrey, G. R. & Lewin, K. F.
System: The UNT Digital Library
New methods and instrumentation for the characterization of biopolymers using electrospray ionization-mass spectrometry (open access)

New methods and instrumentation for the characterization of biopolymers using electrospray ionization-mass spectrometry

The technique of electrospray ionization (ESI) has significantly extended the ability to characterize large molecules by mass spectrometry. Proteins to at least 200,000 D can be transferred intact to the gas phase and molecular weights determined with precisions as high as 0.001% if individual charge states can be resolved. The ESI-MS can also serve as a near ideal interface and detector for capillary column separations providing a basis for highly efficient sample utilization. Using capillary electrophoresis (CE)-MS, injection quantities in the 10{sup {minus}18} mole range can be detected for smaller polypeptides using selected ion monitoring, and separation efficiencies as high as 5{center_dot}10{sup 5} theoretical plates have been realized. We have recently shown that the use of small 5 {mu}m i.d. capillaries allows CE-MS with scanning detection for proteins for injection of 600 attomoles.
Date: September 1, 1992
Creator: Smith, R. D.; Udseth, H. R.; Rockwood, A. L.; Winger, B. E.; Hofstadler, S. A.; Goodlett, D. R. et al.
System: The UNT Digital Library
Mind, matter, and Pauli (open access)

Mind, matter, and Pauli

The role of subjective experience in physical theory is discussed, with particular attention to the later ideas of Wolfgang Pauli. These ideas appear to open the door to a unified framework for the development of science.
Date: September 10, 1992
Creator: Stapp, H. P.
System: The UNT Digital Library