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Ninth topical conference on atomic processes in plasmas (open access)

Ninth topical conference on atomic processes in plasmas

None
Date: December 31, 1993
Creator: unknown
System: The UNT Digital Library
High-efficiency target-ion sources for RIB generation (open access)

High-efficiency target-ion sources for RIB generation

A brief review is given of high-efficiency ion sources which have been developed or are under development at ISOL facilities which show particular promise for use at existing, future, or radioactive ion beam (RIB) facilities now under construction. Emphasis will be placed on those sources which have demonstrated high ionization efficiency, species versatility, and operational reliability and which have been carefully designed for safe handling in the high level radioactivity radiation fields incumbent at such facilities. Brief discussions will also be made of the fundamental processes which affect the realizable beam intensities in target-ion sources. Among the sources which will be reviewed will be selected examples of state-of-the-art electron-beam plasma-type ion sources, thermal-ionization, surface-ionization, ECR, and selectively chosen ion source concepts which show promise for radioactive ion beam generation. A few advanced, chemically selective target-ion sources will be described, such as sources based on the use of laser-resonance ionization, which, in principle, offer a more satisfactory solution to isobaric contamination problems than conventional electromagnetic techniques. Particular attention will be given to the sources which have been selected for initial or future use at the Holifield Radioactive Ion Beam Facility now under construction at the Oak Ridge National Laboratory.
Date: December 31, 1993
Creator: Alton, G. D.
System: The UNT Digital Library
A Monte Carlo study of the ``minus sign problem`` in the t-J model using an intel IPSC/860 hypercube (open access)

A Monte Carlo study of the ``minus sign problem`` in the t-J model using an intel IPSC/860 hypercube

We describe a Monte Carlo simulation of the 2-dimensional t-J model on an Intel iPSC/860 hypercube. The problem studied is the determination of the dispersion relation of a dynamical hole in the t-J model of the high temperature superconductors. Since this problem involves the motion of many fermions in more than one spatial dimensions, it is representative of the class of systems that suffer from the ``minus sign problem`` of dynamical fermions which has made Monte Carlo simulation very difficult. We demonstrate that for small values of the hole hopping parameter one can extract the entire hole dispersion relation using the GRW Monte Carlo algorithm, which is a simulation of the Euclidean time Schroedinger equation, and present results on 4 {times} 4 and 6 {times} 6 lattices. We demonstrate that a qualitative picture at higher hopping parameters may be found by extrapolating weak hopping results where the minus sign problem is less severe. Generalization to physical hopping parameter values will only require use of an improved trial wavefunction for importance sampling.
Date: December 31, 1993
Creator: Kovarik, M. D. & Barnes, T.
System: The UNT Digital Library
Ninth target fabrication specialists` meeting: Proceedings (open access)

Ninth target fabrication specialists` meeting: Proceedings

This report contains a collection of viewgraphs and short papers on target fabrication for inertial confinement purposes.
Date: December 31, 1993
Creator: unknown
System: The UNT Digital Library
Cavity-QED enhancement of fluorescence yields in microdroplets (open access)

Cavity-QED enhancement of fluorescence yields in microdroplets

Measurements of the integrated fluorescence yield of Rhodamine 6G (R6G) in levitated microdroplets (4 to 16 {mu}m diameter) display a size dependence which is attributed to a decreased probability per excitation cycle of photochemical bleaching as a result of cavity-enhanced spontaneous emission rates. The average number of fluorescence photons detected per molecule in 4 {mu}m droplets (where emission rate enhancement has been previously demonstrated) is shown to be approximately a factor of 2 larger than the yield measured for larger droplets where emission rate enhancement does not occur. Within some simple approximations, these results suggest that essentially no emission rate inhibition occurs in this system. A mechanism based on spectral diffusion is postulated for the apparent absence of cavity-inhibited emission and is illustrated by Monte Carlo calculations using time-dependent lineshape functions.
Date: December 31, 1993
Creator: Barnes, M. D.; Whitten, W. B. & Ramsey, J. M.
System: The UNT Digital Library
Comparison of the folded stripline and stacked stripline concepts to the folded waveguide launcher (open access)

Comparison of the folded stripline and stacked stripline concepts to the folded waveguide launcher

Two new concepts are being developed as possible upgrades to the folded waveguide launcher. The folded stripline is a folded waveguide with an additional conductor positioned inside. The term stripline refers to the resemblance of the design to microwave microstrip line. The conductor provides support for TEM mode propagation, which eliminates cutoff and the nonlinear frequency dependence of the waveguide impedance and phase velocity. A natural extension to the folded stripline is the stacked stripline, which comprises several stacked, independent TEM waveguides. Initial measurements indicate that both concepts have better magnetic flux coupling than the folded waveguide.
Date: December 31, 1993
Creator: Gardner, W. L.; Caughman, J. B. O.; Hoffman, D. J. & Probert, P. H.
System: The UNT Digital Library
Abstracts of papers presented at the LVIII Cold Spring Harbor Symposium on quantitative Biology: DNA and chromosomes (open access)

Abstracts of papers presented at the LVIII Cold Spring Harbor Symposium on quantitative Biology: DNA and chromosomes

This volume contains the abstracts of oral and poster presentations made at the LVIII Cold Spring Harbor Symposium on Quantitative Biology entitles DNA & Chromosomes. The meeting was held June 2--June 9, 1993 at Cold Spring Harbor, New York.
Date: December 31, 1993
Creator: unknown
System: The UNT Digital Library
Analyses of a steel containment vessel with an outer contact structure under severe internal overpressurization conditions (open access)

Analyses of a steel containment vessel with an outer contact structure under severe internal overpressurization conditions

Many Mark-I and Mark-II BWR plants are designed with a steel vessel as the primary containment. Typically, the steel containment vessel (SCV) is enclosed within a reinforced concrete shield building with only a small gap (50--90mm) separating the two structures. This paper describes finite element analyses performed to evaluate the effects of contact and friction between a steel containment vessel and an outer contact structure when the containment vessel is subjected to large internal pressures. These computations were motivated by a joint program on containment integrity involving the Nuclear Power Engineering Corporation (NUPEC) of Japan, the US Nuclear Regulatory Commission (NRC), and Sandia National Laboratories for testing model containments.
Date: December 31, 1993
Creator: Porter, V. L.
System: The UNT Digital Library
Low emissions combustor test facility (open access)

Low emissions combustor test facility

The Morgantown Energy Technology Center (METC) is in the process of constructing a low emissions combustor test and research (LECTR) facility designed to support the development of low emissions gas turbine combustion systems fired on natural gas and coal derived gaseous fuels containing fuel bound nitrogen. The LECTR facility is a major test station located within METC`s new combustion facility. The heart of this test station is a 60 centimeter (24 inch) diameter, refractory lined pressure vessel made up of a series of flanged modules. The facility design offers the flexibility to test a variety of low emissions combustion concepts at pressures up to 3 MPa (30 atm). Upon completion of fabrication and shake-down testing in January of 1994, the facility will be available for use by industrial and university partners through Cooperative Research and Development Agreements (CRADAs) or through other cooperative arrangements. This paper is intended to describe the LECTR facility and associated operating parameter ranges and to inform interested parties of the facility availability.
Date: December 1, 1993
Creator: Maloney, D. J.; Hadley, M. S. & Norton, T. S.
System: The UNT Digital Library
Proceedings of the seventh symposium on containment of underground nuclear explosions. Volume 1 (open access)

Proceedings of the seventh symposium on containment of underground nuclear explosions. Volume 1

This is Volume 1 of two unclassified volumes of a meeting of workers at all levels in the science and technology of containment. Papers on containment and related geological, geophysical, engineering, chemical, and computational topics were included. Particular topics included in this volume are: General containment,tunnel and LOS topics, cavity conditions, and LYNER and chemical kiloton. Individual papers are indexed separately on the data base.
Date: December 31, 1993
Creator: Olsen, C. W.
System: The UNT Digital Library
Cosmological string solutions by dimensional reduction (open access)

Cosmological string solutions by dimensional reduction

We obtain cosmological four dimensional solutions of the low energy effective string theory by reducing a five dimensional black hole, and black hole-de Sitter solution of the Einstein gravity down to four dimensions. The appearance of a cosmological constant in the five dimensional Einstein-Hilbert produces a special dilaton potential in the four dimensional effective string action. Cosmological scenarios implement by our solutions are discussed.
Date: December 1, 1993
Creator: Behrndt, K. & Foerste, S.
System: The UNT Digital Library
Modified impedance control for robotic saw cutting: Simulation and implementation in three degrees of freedom (open access)

Modified impedance control for robotic saw cutting: Simulation and implementation in three degrees of freedom

The Savannah River Site (SRS) production and decommissioning operations produce solid radioactive transuranic (TRU) waste. This waste must be repackaged and sent to the Waste Isolation Pilot Plant (WIPP) for permanent disposal. The Savannah River Technology Center (SRTC) built a test facility to demonstrate simulated waste processing. The test facility use`s a CIMCORP multi-axis robot system, a CIMROC{trademark} II robot controller, and an electric circular saw to remotely open and size reduce plywood crates. The robot can either be teleoperated using joysticks or autonomously controlled via the, CIMROC{trademark} II. Both methods are inadequate for circular saw cutting of plywood crates due to frequent saw blade binding. Blade binding results from the current commercial robot controller limitations. The limitations are overcome by incorporating additional sensor information into the existing controller structure. In this paper we utilize a force sensor and a frequency counter to implement a modified impedance controller which prevents saw blade binding.
Date: December 31, 1993
Creator: Kriikku, E. M.; Reynolds, D. L.; Carroll, J. J. & Dawson, D. M.
System: The UNT Digital Library
Proceedings of the Fifth International Workshop on Next-Generation Linear Colliders. Addendum (open access)

Proceedings of the Fifth International Workshop on Next-Generation Linear Colliders. Addendum

None
Date: December 31, 1993
Creator: Paterson, J. M. & Asher, K.
System: The UNT Digital Library
Open problems of computational molecular biology (open access)

Open problems of computational molecular biology

None
Date: December 31, 1993
Creator: unknown
System: The UNT Digital Library
Hunton Group core workshop and field trip (open access)

Hunton Group core workshop and field trip

The Late Ordovician-Silurian-Devonian Hunton Group is a moderately thick sequence of shallow-marine carbonates deposited on the south edge of the North American craton. This rock unit is a major target for petroleum exploration and reservoir development in the southern Midcontinent. The workshop described here was held to display cores, outcrop samples, and other reservoir-characterization studies of the Hunton Group and equivalent strata throughout the region. A field trip was organized to complement the workshop by allowing examination of excellent outcrops of the Hunton Group of the Arbuckle Mountains.
Date: December 31, 1993
Creator: Johnson, K. S.
System: The UNT Digital Library
Solutions of TEAM Problem No. 13 using integral equations in a sequential and parallel computing environment (open access)

Solutions of TEAM Problem No. 13 using integral equations in a sequential and parallel computing environment

In this paper a brief discussion of h-type volume integral formulations implemented in GFUNET/CORAL code is given and solutions of TEAM benchmark No. 13 are shown. GFUNET/CORAL is a general purpose code for 2D and 3D magnetostatics. Solutions of TEAM problem No. 13 are computed using both a sequential and parallel version of GFUNET/CORAL.
Date: December 31, 1993
Creator: Kettunen, L.; Forsman, K.; Levine, D. & Gropp, W.
System: The UNT Digital Library
Opportunities and prospects for demand-side efficiency improvements (open access)

Opportunities and prospects for demand-side efficiency improvements

Substantial progress has been made over the last 20 years in improving energy efficiency in all sectors of the US economy. Although there remains a large potential for further efficiency gains, progress in improving energy efficiency has slowed recently. A combination of low energy prices, environmental challenges, and life-style changes have caused energy consumption to resume rising. Both new policies and technologies will be necessary to achieve cost-effective levels of energy efficiency. This paper describes some of the promising new demand-side technologies that are currently being implemented, nearing commercialization, or in advanced stages of development. The topics discussed include finding replacements for chlorofluorocarbons (CFCs), new building equipment and envelope technologies, lessons learned about conservation program implementation, and the role of utilities in promoting the efficient use of energy.
Date: December 31, 1993
Creator: Kuliasha, M. A.
System: The UNT Digital Library
Scientific and Technical Information (STI)....what`s the status? (open access)

Scientific and Technical Information (STI)....what`s the status?

In 1982, the Pacific Northwest Laboratory (PNL) developed an electronic Publications and Presentations Registry designed to track Scientific and Technical Information (STI) products through PNL and Department of Energy (DOE) programmatic reviews. All information forwarded to the Office of Scientific and Technical Information (OSTI) for release (e.g., public, UCNI, Export Control) is included in the database. The database contains client and programmatic information for all STI generated by PNL. This electronic format is currently one of the most comprehensive resources for PNL authored and co-authored documents on the Hanford Site.
Date: December 1, 1993
Creator: Varley, D. A.
System: The UNT Digital Library
The application of electrodialysis to extend the lifetime of commercial electroplating baths (open access)

The application of electrodialysis to extend the lifetime of commercial electroplating baths

Electrodialysis has been investigated as a method to extend the lifetime of industrial electroplating solutions via the selective removal of inert electrolyte salts that build up during electroplating operations. The electrodialysis measurements were made using a commercially available plate-and frame-type cell and various combinations of Nafion cation ``change and either Tosflex or Neosepta anion exchange membranes. Two commercial plating solutions were studied: a zinc-tin bath in which there is a buildup of excess potassium hydroxide and a nickel-tungsten bath characterized by a buildup of excess sodium sulfate. Potassium hydroxide was effectively removed from the zinc-tin bath with very little loss of the heavy metals. Two configurations were investigated: a three compartment configuration with potassium hydroxide in the anolyte strip and sulfuric acid in the catholyte strip, and a two compartment configuration with sulfuric acid in the catholyte strip and the anode placed directly in the plating solution. In both cases potassium hydroxide was stripped from the plating solution at greater than 94% current efficiency, but at a slightly greater voltage in the three compartment cell due to increased resistance caused by the extra membrane. A three compartment configuration was used to remove sodium sulfate from the nickel-tungsten bath, with acid …
Date: December 31, 1993
Creator: Purdy, G.; Zawodzinski, C.; Smith, B. & Smith, W. H.
System: The UNT Digital Library
Digital map and spatial database requirements for advanced traffic management systems (open access)

Digital map and spatial database requirements for advanced traffic management systems

Advanced Traffic Management Systems (ATMS) depend on good-quality digital maps and spatial databases. Concerns over the availability of digital maps and spatial databases for ATMS`s in the United States were initially raised in early meetings of IVHS America ATMS committee. While there has been little argument regarding the important role of the private sector in providing ``value-added`` data for sale to public and private parties, the IVHS community has since been engaged in a lively debate over the appropriates roles of the public and private sectors in providing ``base data`` for the nation`s Intelligent Vehicle and Highway Systems. This paper summarizes the activities of the ATMS Committee over the past 1 1/2 years and offers recommendations for next steps to be taken toward laying the foundations for efficient and effective deployment of digital map and spatial database resources for use in advanced traffic management systems.
Date: December 31, 1993
Creator: Lerner-Lam, E.; Smith, W. T.; Francisca, J. R. & Rathi, A.
System: The UNT Digital Library
Regulation of hazardous air pollutants emitted from fossil-fired boilers (open access)

Regulation of hazardous air pollutants emitted from fossil-fired boilers

The changes made in {section}112 of the Clean Air Act by the 1990 Amendments to the Act will affect the regulation of hazardous air pollutants (HAPs) emitted by fossil-fired boilers. The 1990 Amendments designated 189 chemicals/compounds as HAPS. Major and area sources of these pollutants in categories designated by the Environmental Protection Agency (EPA) will be subject to emission standards set by EPA. Industrial and institutional/commercial boilers are two such categories of HAPs designated by EPA for which emission standards will be issued. Fossil-fired boilers can emit a variety of HAPS. All or a portion of such emissions that exceed designated thresholds are likely to be regulated. This paper discusses how the 1990 amendments impact fossil-fired boilers. The steps are outlined which can be taken by owners of industrial and institutional/commercial boilers before the final emission standards are issued. These steps include participation in EPA`s standard setting process, participation in EPA`s early reduction program to delay the time when compliance with the maximum achievable control technology (MACT) standard is required, and consideration of any planned modifications to a facility which might subject that facility to a MACT standard set in advance of the EPA-set standard.
Date: December 1, 1993
Creator: Hendrickson, P. L. & Daellenbach, K. K.
System: The UNT Digital Library
New concepts for refrigerant leak detection and mixture measurement (open access)

New concepts for refrigerant leak detection and mixture measurement

Since the discovery that chlorofluorocarbons (CFCs) destroy the ozone layer, the need to reduce the release of these refrigerants into the environment has become critical. A total ban of ozone-depleting CFCs is expected within a few years, and hydrofluorocarbons (HFCs) and fluorocarbons (FCs) and their mixtures are expected to be used during a transition period. Several HFC and FC refrigerants are currently being considered as CFC substitutes. The electronic refrigerant leak detectors currently being considered as CFC substitutes. The electronic refrigerant leak detectors currently on the market were developed to detect CFCs and are not as sensitive to HFCs. Although incremental improvement can be made to these devices to detect HFCs, they often lead to increased false signals. Also, there is no simple device available to measure the composition of a refrigerant mixture. The authors present two new concepts to aid in the development of two portable instruments that can be used for HFC leak detection and for quantitative measurement of refrigerant mixture compositions. The development of simple, easy-to-use portable leak detectors and refrigerant mixture meters is essential to the wide use of alternative refrigerants in industry.
Date: December 31, 1993
Creator: Chen, F. C.; Allman, S. L. & Chen, C. H.
System: The UNT Digital Library
Proceedings of the seventh symposium on containment of underground nuclear explosions. Volume 2 (open access)

Proceedings of the seventh symposium on containment of underground nuclear explosions. Volume 2

This is Volume 2 of two unclassified volumes of a meeting of workers at all levels in the science and technology of containment. Papers on containment and related geological, geophysical, engineering, chemical, and computational topics were included. Particular topics in this volume include: Low-yield test beds, modeling and residual stress, material properties, collapse phenomena and shock diagnostics, stemming practices and performance, geophysics, and geosciences and weapons destruction. Individual papers are indexed separately on the data base.
Date: December 31, 1993
Creator: Olsen, C. W.
System: The UNT Digital Library
Reinventing information services to increase customer satisfaction (open access)

Reinventing information services to increase customer satisfaction

In this paper, the author presents her view of the role of an information service and proposes means of improving information customer service and satisfaction. The emphasis of the paper is on placing the primary value on the information customer rather than on the information itself. After receiving a request for information, the information service should strive for speed and accuracy of service to provide full-text sources in a language and format convenient to the customer. The author stresses that information professionals need to re-evaluate their roles to correctly assess and rectify customers` information deficiencies.
Date: December 1, 1993
Creator: Madison, J. E.
System: The UNT Digital Library