THE COUPLING IMPEDANCE OF THE RHIC INJECTION KICKER SYSTEM. (open access)

THE COUPLING IMPEDANCE OF THE RHIC INJECTION KICKER SYSTEM.

IN THIS PAPER, RESULTS FROM IMPEDANCE MEASUREMENTS ON THE RHIC INJECTION KICKERS ARE REPORTED. THE KICKER IS CONFIGURED AS A ''C'' CROSS SECTION MAGNET WITH INTERLEAVED FERRITE AND HIGH-PERMITTIVITY DIELECTRIC SECTIONS TO ACHIEVE A TRAVELLING WAVE STRUCTURE. THE IMPEDANCE WAS MEASURED USING THE WIRE METHOD, AND ACCURATE RESULTS ARE OBTAINED BY INTERPRETING THE FORWARD SCATTERING COEFFICIENT VIA THE LONG-FORMULA. THE FOUR KICKERS WITH THEIR CERAMIC BEAM TUBES CONTRIBUE AT Z/N-0.22 OMEGA/RING IN THE INTERESTING FREQUENCY RANGE FROM 0.1 TO 1 BHZ, AND LESS ABOVE.
Date: June 28, 1999
Creator: Hahn, H.
Object Type: Article
System: The UNT Digital Library
Electronic effects at interfaces in Cu - Cr, Mo, Ta, Re Multilayers (open access)

Electronic effects at interfaces in Cu - Cr, Mo, Ta, Re Multilayers

In this study we characterize electronic effects in short-period ({approx}20 {angstrom}) metallic multilayer films in which 40% of the atoms are at an interface using near-edge (L{sub 3,2}) x-ray absorption. This study investigates Cu/TM where TM = Cr, MO, W, Ta, Re. These immiscible elemental pairs are ideal to study as they form no compounds and exhibit terminal solid solubility. An interest in the charge transfer between elements in alloys and compounds has led to studies using x-ray absorption as described above. Near edge x-ray absorption fine structure (NEXAFS), a technique used for analyzing x-ray absorption near the absorption edge of the element, is especially suited to study the amount of unoccupied states in the conduction band of a metal. The d-metals spectra show large peaks at the absorption edges called ''white lines.'' These are due to the unoccupied d-states just above the Fermi level in these metals. A study of the white lines in the 3d metals show that as the d-band is increasingly occupied the white lines decrease in intensity. Starting with Ti (3d{sup 2} 4s{sup 2}), which has an almost empty d-band and shows strong white lines, the white-line intensities decrease across the Periodic Chart to Cu …
Date: June 28, 1999
Creator: Barbee, T. W.; Bello, A. F.; Klepeis, J. E. & Van Buuren, T.
Object Type: Report
System: The UNT Digital Library
In-situ laser Raman scattering and far infrared spectroscopy studies of corrosion-passivation phenomena in metals. (open access)

In-situ laser Raman scattering and far infrared spectroscopy studies of corrosion-passivation phenomena in metals.

Vibrational spectroscopic and electrochemical techniques are among the most useful tools for the elucidation of corrosion-passivation phenomena in metals. The former can provide information on the structure and composition of corrosion films ''in situ'' in aqueous solution environments, while thermodynamic and kinetic information may be obtained using electrochemical techniques. In this paper, we demonstrate the application of Laser Raman Scattering (LRS) and Synchrotrons Far Infrared Reflectance Spectroscopy (SFIRS), coupled with electrochemical methods, for the determination of the structure and composition of surface films on nickel and copper in aqueous solution environment. The corrosion film on nickel has been found to consist of NiO and Ni(OH){sub 2} in the passive region of potential and NiOOH in the transpassive region. The film on copper consists of Cu{sub 2}O, CUO and Cu(OH){sub 2}. We also show for the first time that SFIRS can be used to obtain information on the adsorption of ions on a metal surface with sub-monolayer sensitivity. Adsorption of Cl{sup {minus}}, Br{sup {minus}}, SO{sup {minus}2}, and PO{sub 4}{sup {minus}3} was found to occur at gold electrodes in perchloric acid solution. We also observed that when two different ions are present in solution, the more strongly adsorbed ion determined the corrosion …
Date: June 28, 1999
Creator: Melendres, C. A.
Object Type: Article
System: The UNT Digital Library
Selecting and implementing the PBS scheduler on an SGI Onyx 2/Orgin 2000. (open access)

Selecting and implementing the PBS scheduler on an SGI Onyx 2/Orgin 2000.

In the Mathematics and Computer Science Division at Argonne, the demand for resources on the Onyx 2 exceeds the resources available for consumption. To distribute these scarce resources effectively, we need a scheduling and resource management package with multiple capabilities. In particular, it must accept standard interactive user logins, allow batch jobs, backfill the system based on available resources, and permit system activities such as accounting to proceed without interruption. The package must include a mechanism to treat the graphic pipes as a schedulable resource. Also required is the ability to create advance reservations, offer dedicated system modes for large resource runs and benchmarking, and track the resources consumed for each job run. Furthermore, our users want to be able to obtain repeatable timing results on job runs. And, of course, package costs must be carefully considered. We explored several options, including NQE and various third-party products, before settling on the PBS scheduler.
Date: June 28, 1999
Creator: Bittner, S.
Object Type: Article
System: The UNT Digital Library
High-power vacuum window in WR10 (open access)

High-power vacuum window in WR10

Results are presented for fabrication and test of a WR10 waveguide window, for use in ultra-high vacuum at 91.4 GHz. Low-power bench measurements are compared with analytic and simulation results. Operation at approximately equal to 4-kW peak power, duty factor 10{sup {minus}6} and 10{sup {minus}9}-scale vacuum is noted.
Date: June 28, 1999
Creator: Hill, Marc E
Object Type: Report
System: The UNT Digital Library
Electrical resistivity measurements of brine saturated porous media near reservoir conditions: Awibengkok preliminary results (open access)

Electrical resistivity measurements of brine saturated porous media near reservoir conditions: Awibengkok preliminary results

Laboratory measurements of the electrical resistivity of rocks and synthetic rocks with confining pressures up to 100 bars and temperatures between 20 and 211 C were performed to further investigate how the pore-size distribution and capillarity affects boiling in porous media. Similar to previous measurements on samples from The Geysers, CA, we observed a gradual increase in resistivity when pore pressure was decreased below the phase-boundary pressure of free water, an indication that boiling is controlled not only by temperature and pressure, but also by pore size distribution. Other important phenomena observed were strong resistance fluctuations during boiling that may be chaotic, and salt deposition that caused sample cracking. If confirmed in further experiments, these results may lead to a new geophysical diagnostic for locating boiling in high permeability areas of geothermal reservoirs and for methods of permeability alteration.
Date: June 28, 1999
Creator: Bonner, B.; Duba, A. & Roberts, J.
Object Type: Article
System: The UNT Digital Library
Hartree-Fock Mean-Field Models Using Separable Interactions (open access)

Hartree-Fock Mean-Field Models Using Separable Interactions

An effective two-body nuclear interaction is presented which is a sum of terms separable in coordinate space. Calculations are made using this interaction of some doubly closed-shell spherical nuclei using many-body perturbation theory with the Hartree-Fock state as a reference state. It is demonstrated that the interaction gives good bulk properties in finite nuclei.
Date: June 28, 1999
Creator: Stevenson, P.; Stone, J. R. & Strayer, M. R.
Object Type: Article
System: The UNT Digital Library
Waste characterization activities at the Lawrence Livermore National Laboratory (open access)

Waste characterization activities at the Lawrence Livermore National Laboratory

Radioactive and hazardous wastes are generated at many national laboratories, military sites, fuel fabrication and enrichment plants, reactors, and many other facilities. At all of these sites, wastes must be separated, categorized, possibly treated, and packed into containers for shipment to waste-storage or disposal sites. Prior to treatment, storage or, shipment, the containers must be characterized to determine the ultimate disposition of the contained waste. Comprehensive and accurate nondestructive evaluation (NDE) and nondestructive assay (NDA) methods can be used to characterize most waste containers in a safe and cost-effective manner without opening them. The Lawrence Livermore National Laboratory (LLNL) is investigating and developing the application of x-ray and {gamma}-ray methods to nonintrusively characterize waste containers and/or items. X-ray NDE methods are being investigated to determine whether they can be used to identify hazardous and nonconforming materials. A {gamma}-ray NDA method is used to identify the radioactive sources within a container and to accurately quantify their strength. In this paper we describe five waste characterization projects being conducted at LLNL that apply both the NDE and NDA methods and present results.
Date: June 28, 1995
Creator: Roberson, G. P.; Martz, H. E. & Haskins, J. J.
Object Type: Article
System: The UNT Digital Library
Interfacial effects in multilayers (open access)

Interfacial effects in multilayers

There are many physical characterization approaches which evaluate a limited set of structural elements in multilayers: they study a single interface; they study a single layer of material; they study a very small sample of a multilayer. On a broader basis, the interference phenomena on which the performance of x-ray optic multilayers is based integrates over the full area/volume of the multilayer illuminated. In order to gain understanding of the impact of imperfections on multilayer performance it is necessary to develop an experimental approach that provides detailed information about the effects of interfaces in the multilayer obtained when the multilayer is being applied in a manner directly related to application. Additionally, it is also of interest to determine the breadth of application of any such experimental approach to the general study of interfaces in solids. The primary goal in this research was to develop an experimental methodology to quantitatively characterize both the physical and electronic characteristics of interfaces in multilayer structures. The approach was to fabricate multilayers from three elements so that one monolayer or less thick ''marker layers'' were selectively deposited on a given set interfaces in the multilayer. These ''marker layers'' could then interrogated by scattering and fluorescence …
Date: June 28, 1999
Creator: Barbee, T. W.
Object Type: Report
System: The UNT Digital Library
Technology development for cobalt F-T catalysts. Quarterly technical progress report number 10, January 1--March 31, 1995 (open access)

Technology development for cobalt F-T catalysts. Quarterly technical progress report number 10, January 1--March 31, 1995

The goal of this project is the development of a commercially-viable, cobalt-based Fischer-Tropsch (F-T) catalyst for use in a slurry bubble column reactor. The major objectives of this work are (1) to develop a cobalt-based F-T catalyst with low (< 5%) methane selectivity, (2) to develop a cobalt-based F-T catalyst with water-gas shift activity, and (3) to combine both these improvements into one catalyst. The project consists of five major tasks: catalyst development; catalyst testing; catalyst reproducibility tests; catalyst aging tests; and preliminary design and cost estimate for a demonstrate scale catalyst production facility. Technical accomplishments during this reporting period include the following. It appears that the higher activity obtained for the catalysts prepared using an organic solution and reduced directly without prior calcination was the result of higher dispersions obtained under such pretreatment. A Ru-promoted Co catalyst on alumina with 30% Co loading exhibited a 4-fold increase in dispersion and a 2-fold increase in activity in the fixed-bed reactor from that obtained with the non-promoted catalyst. Several reactor runs have again focused on pushing conversion to higher levels. The maximum conversion obtained has been 49.7% with 26g catalyst. Further investigations of the effect of reaction temperature on the performance …
Date: June 28, 1995
Creator: Singleton, Alan H.
Object Type: Report
System: The UNT Digital Library
Robust Detection of Dynamical Change in Scalp EEG (open access)

Robust Detection of Dynamical Change in Scalp EEG

We present a robust, model-independent technique for measuring changes in the dynamics underlying nonlinear time-serial data. We define indicators of dynamical change by comparing distribution functions on the attractor via L{sub 1}-distance and X{sup 2} statistics. We apply the measures to scalp EEG data with the objective of capturing the transition between non-seizure and epileptic brain activity in a timely, accurate, and non-invasive manner. We find a clear superiority of the new metrics in comparison to traditional nonlinear measures as discriminators of dynamical change.
Date: June 28, 1999
Creator: Gailey, P.C.; Hively, L.M. & Protopopescu, V.A.
Object Type: Article
System: The UNT Digital Library
Methods for Geometric Modeling of Electronic Inspection Data (open access)

Methods for Geometric Modeling of Electronic Inspection Data

The Oak Ridge Y-12 plant has implemented a methodology for characterizing parts and assemblies based on their as-measured condition. Complete solid models of each part in an assembly are created to represent these measurements. The models produced can be analyzed for mass properties, relative shape variations, interference checking, and optimal mating between components. This report describes the methodology used to take a relatively sparse set of measured inspection points and generate a representative fully analytical solid model.
Date: June 28, 1999
Creator: Taylor, J. R.
Object Type: Report
System: The UNT Digital Library
A Lattice for the 50 Gev Muon Collider Ring. (open access)

A Lattice for the 50 Gev Muon Collider Ring.

A resent progress report on the lattice design of the 50-50 GeV muon collider is presented. The ring circumference needs to be as small as possible due to the short lifetime of the 50 GeV muons. The background at the detector is affected by the continuous decay of muons into electrons which requires a dipole between the high focusing quadrupoles and the detector. To obtain a luminosity on the order of 1 x 10{sup 33} cm{sup {minus}2} S{sup {minus}1} it is required to have beam intensities on the order of 1 x 10{sup 12} particles per bunch. The rms momentum spread of the beam is equal to 0.12% and the beta functions at the interaction point are equal to 4 cm. The maxima of the betatron functions at these quadrupoles are 1300 m, resulting in large chromaticities which must be corrected by local chromatic correction. Pairs of horizontal and vertical chromatic sextupoles are located at locations where the corresponding betatron functions are 100 m and the values of the horizontal dispersion functions are 3 and 2 m, respectively. They are carefully placed so that most of their nonlinear effects are canceled. The dynamic aperture is larger than 7 times the …
Date: June 28, 1998
Creator: Trbojevic, D.
Object Type: Article
System: The UNT Digital Library
A Precision Measurement of the Spin Structure Function g{sub 1}(x,Q{sup 2}) for the Proton and Deuteron (open access)

A Precision Measurement of the Spin Structure Function g{sub 1}(x,Q{sup 2}) for the Proton and Deuteron

A precision measurement of the spin structure function g{sub 1}(x,Q{sup 2}) for both the proton and deuteron was made using deep inelastic scattering of the 48.35 GeV polarized electron beam at the Stanford Linear Accelerator Center. The kinematic range of the measurement was 0.014 &lt; x &lt; 0.9 and 1 (GeV/c){sup 2} &lt; Q{sup 2} &lt; 40 (GeV/c){sup 2}. Solid {sup 15}NH{sub 3} and {sup 6}Li{sup 2}H were used as target materials. The beam polarization of 0.81 {+-} 0.02 was measured using Moeller polarimetry. The scattered electron events were accumulated in three magnetic spectrometers at fixed angles of 2.75{sup o}, 5.5{sup o}, and 10.5{sup o}. Data were obtained with the target polarization direction both parallel and transverse to the beam direction. Together with existing world data, the g{sub 1}(x,Q{sup 2}) results were fit in a well-established next-to-leading order QCD formalism, and are consistent with the Bjorken sum rule.
Date: June 28, 1999
Creator: Mitchell, Gregory
Object Type: Report
System: The UNT Digital Library
X-ray waveguides for high resolution x-ray analysis (open access)

X-ray waveguides for high resolution x-ray analysis

The project goals were to model, synthesize, and characterize thin-film, x-ray waveguide structures to determine whether such nanostructurcs can be fabricated with the precision required for true waveguide operation at x-ray energies. In FY98, we designed, fabricated, and characterized (at the Stanford Synchrotron Radiation Laboratory) optimized. thin-film, x-ray waveguide structures (XWGs) as resonant concentrators of x-rays which may be applied as diffraction-limited, linear x-ray sources. We fabricated nine waveguide structures that were optimized to operate in the cavity modes m = 1,2,3 and tested them at x-ray energies of 6 to 10 keV. The observed performances were compared to the calculations based on the design structures and excellent agreement was demonstrated. This project plan is presented in TABLE 1 that includes all aspects of the development of these unique thin film x-ray optical devices. X-ray waveguide designs were made using a standard x-ray multilayer x-ray optic Fresnel code. Materials were selected on the basis of calculated performance as well as sputter deposition characteristics. Laboratory x-ray reflectivity measurements were made prior to the SSRL experimental run to assess the quality of the samples. Cross-section Transmission Electron Microscopy observations of selected sample were made to enable assessment of the relationship between the …
Date: June 28, 1999
Creator: Barbee, T W
Object Type: Report
System: The UNT Digital Library
2nd Workshop on Satellites for Solar Energy Assessments (open access)

2nd Workshop on Satellites for Solar Energy Assessments

A Collection of Presentations on new techniques for developing climatological estimates of the solar resource at all locations on earth at a resolution of 100km, and of developing estimates at half-hour intervals at resolutions of 10 km or less in specific locations.
Date: June 28, 1999
Creator: Renne, D.
Object Type: Article
System: The UNT Digital Library
Experimental overview of axion searches (open access)

Experimental overview of axion searches

Experimental methods to search for the ``invisible axion`` (f{sub a} {much_gt} 250 GeV) are reviewed. The report focuses on the axion-photon coupling, both for laboratory experiments as well as those looking for stellar or cosmologically produced axions. The conclusion is that while the axion-photon mixing in principle would permit laboratory axion searches which are broadband in mass, in fact no such experiment could have the sensitivity to the axion, where m{sub afa} {approx} m{sub {pi}f{pi}}. The only experiments which promise to have any chance to find the axion are the microwave cavity experiments, which presume axions to constitute our galactic halo dark matter. The conversion of axions into a monochromatic microwave signal in a resonant circuit affords the experiment the extraordinary sensitivity required to see the axion, at the expense of being narrow-band in mass, i.e. a tuning experiment. Two such efforts are underway in the world.
Date: June 28, 1995
Creator: van Bibber, K.
Object Type: Article
System: The UNT Digital Library
Hydrogen production from municipal solid waste (open access)

Hydrogen production from municipal solid waste

We have modified a Municipal Solid Waste (MSW) hydrothermal pretreatment pilot plant for batch operation and blowdown of the treated batch to low pressure. We have also assembled a slurry shearing pilot plant for particle size reduction. Waste paper and a mixture of waste paper/polyethylene plastic have been run in the pilot plant with a treatment temperature of 275{degrees}C. The pilot-plant products have been used for laboratory studies at LLNL. The hydrothermal/shearing pilot plants have produced acceptable slurries for gasification tests from a waste paper feedstock. Work is currently underway with combined paper/plastic feedstocks. When the assembly of the Research Gasification Unit at Texaco (feed capacity approximately 3/4-ton/day) is complete (4th quarter of FY96), gasification test runs will commence. Laboratory work on slurry samples during FY96 has provided correlations between slurry viscosity and hydrothermal treatment temperature, degree of shearing, and the presence of surfactants and admixed plastics. To date, pumpable slurries obtained from an MSW surrogate mixture of treated paper and plastic have shown heating values in the range 13-15 MJ/kg. Our process modeling has quantified the relationship between slurry heating value and hydrogen yield. LLNL has also performed a preliminary cost analysis of the process with the slurry heating …
Date: June 28, 1996
Creator: Wallman, P. H.; Richardson, J. H. & Thorsness, C. B.
Object Type: Article
System: The UNT Digital Library
LLW Notes, Volume 10, Number 4, June 1995 (open access)

LLW Notes, Volume 10, Number 4, June 1995

Newsletter distributed to the Low-Level Radioactive Waste Forum members describing current news, policies, and legislation, as well as other information relevant to the management of low-level radioactive waste.
Date: June 28, 1995
Creator: Afton Associates, Inc.
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
Meta-data based mediator generation (open access)

Meta-data based mediator generation

Mediators are a critical component of any data warehouse; they transform data from source formats to the warehouse representation while resolving semantic and syntactic conflicts. The close relationship between mediators and databases requires a mediator to be updated whenever an associated schema is modified. Failure to quickly perform these updates significantly reduces the reliability of the warehouse because queries do not have access to the most current data. This may result in incorrect or misleading responses, and reduce user confidence in the warehouse. Unfortunately, this maintenance may be a significant undertaking if a warehouse integrates several dynamic data sources. This paper describes a meta-data framework, and associated software, designed to automate a significant portion of the mediator generation task and thereby reduce the effort involved in adapting to schema changes. By allowing the DBA to concentrate on identifying the modifications at a high level, instead of reprogramming the mediator, turnaround time is reduced and warehouse reliability is improved.
Date: June 28, 1998
Creator: Critchlaw, T
Object Type: Article
System: The UNT Digital Library
Steam Pretreatment for Coal Liquefaction. Sixth Quarterly Report, 1 January 1992--31 March 1992 (open access)

Steam Pretreatment for Coal Liquefaction. Sixth Quarterly Report, 1 January 1992--31 March 1992

Steam pretreatment is the reaction of coal with steam at temperatures well below those usually used for solubilization. The objective of the proposed work is to test the application of steam pretreatment to coal liquefaction. Conversion of the autoclave apparatus to rapid heating liquefaction was carried out this quarter following redesign of the coal slurry injection system. The modified equipment and procedure was tested in a simulated liquefaction run without coal. Initial tests of slurried {minus}20 mesh coal showed too rapid settling for successful operation. Coal ground to pass 200 mesh proved suitable, and a impact grinder was put into operation to grind the material under an inert atmosphere. A batch of Illinois No. 6 coal for the, first rapid heating liquefaction tests has been prepared and stored under inert gas. The steam pretreatment of {alpha}-benzylnaphthyl ether was carried out using stainless steel and glass lined reactors. A preparative scale procedure for product separation was developed. The major components were identified and the average product distribution determined for both types of reactors. Pretreatment of {alpha}-naphthylmethyl phenyl ether was also carried out using stainless steel and glass-lined reactors. Separation and analysis of the products has been started. The major components have …
Date: June 28, 1992
Creator: Graff, R. A. & Balogh-Nair, V.
Object Type: Report
System: The UNT Digital Library
45-Day safety screening results for tank 241-U-102, push mode cores 143 and 144 (open access)

45-Day safety screening results for tank 241-U-102, push mode cores 143 and 144

This document is the 45-day report deliverable for tank 241-U-102 push mode core segments collected between April 16, 1996 and May 6, 1996 and received by the 222-S Laboratory between April 17, 1996 and May 8, 1996. The segments were subsampled and analyzed in accordance, with the Tank 241-U-102 Push Mode Core Sampling and analysis Plan (TSAP) (Hu, 1996) and the Safety Screening Data Quality Objective (DQO) (Dukelow, et al., 1995). The analytical results are included in Table 1. Attachment I is a cross reference to relate the tank farm identification numbers to the 222-S Laboratory LabCore sample numbers. The subsamples generated in the laboratory for analysis are identified in these diagrams with their sources shown. The diagram identifying the hydrostatic head fluid (HHF) blank is also included, Primary safety screening results and the raw data from Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA) analyses are included in this report. Two of the samples submitted for DSC analysis exceeded notification limits as stated in the Safety Screening DQO (Dukelow, et al., 1995). Cyanide analysis was requested on these samples and a Reactive System Screening Tool analysis was requested for the sample exhibiting the highest exothenn in accordance with the …
Date: June 28, 1996
Creator: Steen, F. H.
Object Type: Report
System: The UNT Digital Library
Dielectron production in nucleus {plus} nucleus collisions at 1.05 GeV/nucleon (open access)

Dielectron production in nucleus {plus} nucleus collisions at 1.05 GeV/nucleon

Measurements of dielectron production in heavy-ion collisions are valuable probes into the dynamics of the collision process. While the hadronic participants of the collision are subject to strong final state interactions, the coupling of the electron-positron pair to the collision medium is electromagnetic. Dielectrons, therefore suffer little rescattering leaving the interaction and can retain information about their production origins, probing even the early stages in the evolution of the collision. The DiLepton Spectrometer (DLS) collaboration`s original measurements of dielectron production established the existence of the signal at Bevalac energies. The 1992- 93 DLS measurements in nucleus+Nucleus collisions at a kinetic beam energy of 1.05 {ital GeV/nucleon} are the subject of this presentation.
Date: June 28, 1996
Creator: Porter, R. J.; Beedoe, S.; Bougteb, M.; Hallman, T. & Wang, Z. F.
Object Type: Article
System: The UNT Digital Library
EEN-333, revised getter flash procedure (open access)

EEN-333, revised getter flash procedure

EWR No. VTE-188--Tubes processed by flashing getters immediately prior to seal-off from vacuum systems are compared for total residual gas pressure to tubes processed by flashing getters after tubes were sealed off vacuum systems. Comparisons of residual pressures determined from current flows in the cold cathode ion gauge.
Date: June 28, 1960
Creator: Brown, W.C.
Object Type: Report
System: The UNT Digital Library