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385 Matching Results
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A preliminary comparison of beam instabilities among ESRF, APS, and spring-8 x-ray storage ring light sources.
A collaboration has been established among the three highest energy storage ring synchrotron light sources: European Synchrotron Radiation Facility (ESRF) (6 GeV), Advanced Photon Source (APS) (7 GeV), and Super Photon Ring (SPring-8) (8 GeV). The goal is to enhance understanding of impedance and beam instability characteristics for present performance and future machine development. In this paper, we compare the beam instability characteristics of the three rings and present a preliminary discussion of the similarities and differences. Topics for future, in-depth study, such as comparing the effect on the beam of in-vacuum insertion devices (IDs) and small-gap chambers, will be described.
Date:
June 13, 2002
Creator:
Harkay, K.; Nagaoka, R.; Revol, J.-L. & Nakamura, T.
Object Type:
Article
System:
The UNT Digital Library
An evaluation of a user-level data transfer mechanism for high-performance networks.
In this paper, we describe FOBS: a simple user-level communication protocol designed to take advantage of the available bandwidth in a high-bandwidth, high-delay network environment. We compare the performance of FOBS with that of TCP both with and without the so-called Large Window extensions designed to improve the performance of TCP in this type of network environment. We show that FOBS can obtain on the order of 90% of the available bandwidth across both short- and long-haul high-performance network connections. For the long-haul connection, the bandwidth obtained was 1.8 times higher than that of the optimized TCP algorithm. Also, we demonstrate that the additional traffic placed on the network because of the greedy nature of the algorithm is quite reasonable, representing approximately 3% of the total data transferred.
Date:
August 13, 2002
Creator:
Dickens, P. M. & Gropp, W.
Object Type:
Article
System:
The UNT Digital Library
DWPF Melter Air-Lift Bubbler: Development and Testing for Increasing Glass Melt Rates and Waste Dissolution
A DOE Tank Focus Area program to assess possible means of increasing Defense Waste Processing Facility Melter melt rate was initiated in FY01. A lumped parameter comparison of DWPF data with earlier pilot scale data indicated that melter capacity for a given feed was limited by overheating of the glass immediately under the reacting feed.
Date:
December 13, 2002
Creator:
Bickford, D.F.
Object Type:
Report
System:
The UNT Digital Library
Caustic-Side Solvent Extraction: Extended Equilibrium Modeling of Cesium and Potassium Distribution Behavior
An extension of the model developed in FY01 for predicting equilibrium distribution ratios in the Caustic-Side Solvent Extraction (CSSX) process is presented here. Motivation for extending the model arose from the need to predict extraction performance of the recently optimized solvent composition and the desire to include additional waste components. This model involves the extraction of cesium and potassium from different cesium, potassium, and sodium media over a large range of concentrations. Those different media include a large variety of anions such as nitrate, hydroxide, nitrite, chloride, fluoride, sulfate, and carbonate. The model was defined based on several hundreds of experimental data points and predicted satisfactorily the cesium extraction from five different SRS waste simulants. This process model encompassed almost exclusively 1:1:1 metal:anion:ligand species. Fluoride, sulfate, and carbonate species were found to be very little extractable, and their main impact is reflected through their activity effects. This model gave a very good cesium and potassium extraction prediction from sodium salts, which is what is needed when trying to predict the behavior from actual waste. However, the extraction from potassium or cesium salts, and the extraction of sodium could be improved, and some additional effort was devoted to improve the thermodynamic …
Date:
June 13, 2002
Creator:
Delmau, L. H.
Object Type:
Report
System:
The UNT Digital Library
MONITORING POWER PLANT EFFICIENCY USING THE MICROWAVE-EXCITED PHOTOACOUSTIC EFFECT TO MEASURE UNBURNED CARBON
Three test instruments are being evaluated to determine the feasibility of using photo-acoustic technology for measuring unburned carbon in fly ash. The first test instrument is a single microwave frequency system previously constructed to measure photo-acoustic signals in an off-line configuration. This system was assembled and used to begin testing parameters thought to be influential in the resulting photo-acoustic signal output. A standard modulation frequency was chosen based upon signal to noise data gained from experimentation. Sample heterogeneity was tested and found not to be influential. Many other tests were performed during the second quarter. Preliminary results show that compression and photo-acoustic volume have an impact on photo-acoustic signal. Conclusions regarding the data for sample bulk density, temperature, humidity, moisture content, and linearity are pending further review. Conclusions for ambient temperature and humidity are pending further review as well. Simultaneously, a second instrument is to be constructed based in part on lessons learned with the first instrument, and to expand the capabilities of the first instrument. Improvements include a control loop to allow more constant microwave power output and an ability to operate over a range of microwave frequencies. To date, the design of the second instrument has been completed …
Date:
May 13, 2002
Creator:
Brown, Robert C.; Weber, Robert J. & Suby, Andrew A.
Object Type:
Report
System:
The UNT Digital Library
Total System Performance Assessment-License Application Methods and Approach
''Total System Performance Assessment-License Application (TSPA-LA) Methods and Approach'' provides the top-level method and approach for conducting the TSPA-LA model development and analyses. The method and approach is responsive to the criteria set forth in Total System Performance Assessment Integration (TSPAI) Key Technical Issue (KTI) agreements, the ''Yucca Mountain Review Plan'' (CNWRA 2002 [158449]), and 10 CFR Part 63. This introductory section provides an overview of the TSPA-LA, the projected TSPA-LA documentation structure, and the goals of the document. It also provides a brief discussion of the regulatory framework, the approach to risk management of the development and analysis of the model, and the overall organization of the document. The section closes with some important conventions that are utilized in this document.
Date:
September 13, 2002
Creator:
McNeish, J.
Object Type:
Report
System:
The UNT Digital Library
Mechanistic fracture criteria for the failure of human cortical bone
A mechanistic understanding of fracture in human bone is critical to predicting fracture risk associated with age and disease. Despite extensive work, a mechanistic framework for describing how the underlying microstructure affects the failure mode in bone is lacking.
Date:
December 13, 2002
Creator:
Nalla, Ravi K.; Kinney, John H. & Ritchie, Robert O.
Object Type:
Article
System:
The UNT Digital Library
USE OF SLIMHOLE DRILLING TO REDUCE WELL COSTS 30-50%: ARNIM PROSPECT
This report highlights the drilling of two shallow oil wells in Fayette County, Texas. The operator of these two wells was Stanton Mineral Development, Inc. The aim of this project was to successfully complete the two (2) wells, emphasizing tight oversight of the technological aspects, neglect of which are the primary causes of failure in this mature producing region as well as unnecessarily expensive wells. Discussions contained here within are not limited to just the execution of the project itself, but a historical and technical analysis which forms a basis for the decisions made both during drilling and completion. Additionally, there is substantial dialogue covering the financial benefits associated with the findings of this project.
Date:
June 13, 2002
Creator:
McDonald, WM. Stanton & Long, Christopher M.
Object Type:
Report
System:
The UNT Digital Library
Saturation-matric potential relations in gravel
None
Date:
February 13, 2002
Creator:
Tokunaga, Tetsu K.; Wan, Jiamin & Olson, Keith R.
Object Type:
Article
System:
The UNT Digital Library
Defect Structure and Evolution in Silicon Carbide Irradiated to 1 dpa-SiC at 1100 C
Transmission electron microscopy (TEM), swelling measurements, isochronal annealing, and thermal diffusivity testing were used to characterize the effects of radiation damage in SiC. Together, these techniques provided a comprehensive set of tools for observing and characterizing the structure and evolution of radiation-induced defects in SiC as a function of irradiation temperature and dose. In this study, two types of dense, crystalline, monolithic SiC were subjected to irradiation doses up to 1 dpa-SiC at a temperature of 1100 C, as well as post-irradiation annealing up to 1500 C. The microscopic defect structures observed by TEM were correlated to changes in the macroscopic dimensions, thermal diffusivity and thermal conductivity. The results demonstrated the value of using ultrapure {beta}SiC as an effective reference material to characterize the nature of expected radiation damage in other, more complex, SiC-based materials such as SiC/SiC composites.
Date:
May 13, 2002
Creator:
Senor, D. J.; Youngblood, G. E.; Greenwood, L. R.; Archer, D. V.; Alexander, D. L.; Chen, M. C. et al.
Object Type:
Report
System:
The UNT Digital Library
Quantum confinement, carrier dynamics and interfacial processes in nanostructured direct/indirect-gap semiconductor-glass composites
The behavior of semiconductor clusters precipitated in an insulated matrix was investigated. Semiconductor compositions of CdTe, Si and Ge were studies and the insulating matrix was amorphous SiO2. As a function of size, quantum confinement effects were observed in all three composite systems. However significant differences were observed between the direct-gap column 2-6 semiconductors and the indirect-gap column 4 semiconductors. As observed by others, the direct-gap 2-6 semiconductors showed a distinct saturation in the energy-gap blue shift with decreasing size. Theoretical studies using a 20-band k dot p calculation of the electronic and valence bands for a 3-dimensionally confined CdTe semiconductor showed that mixing of the conduction band states leads to a flattening of the central valley. This increases the electron mass drastically and saturates the size dependent blue shift in the bandgap. In contrast, the blue shift in the Si and Ge nanocrystals showed no sign of saturation and increased drastically with decreasing size. In fact, Si and Ge crystals were formed with blue shift values that moved the bandgap to the near UV region. We examined the absorption curves to determine whether the bandgap was direct or indirect in the quantum dots. The results are that the absorption …
Date:
August 13, 2002
Creator:
Simmons, Joseph H.
Object Type:
Report
System:
The UNT Digital Library
Characteristics of aqueous colloids generated by corrosion of metallic uranium fuel.
None
Date:
May 13, 2002
Creator:
Fortner, J. A.; Mertz, C. J. & Seifert, S.
Object Type:
Article
System:
The UNT Digital Library
Record of Decision for the Ford Building Waste Unit (643-11G) Operable Unit
This decision document presents the selected remedial for the Ford Building Waste Unit (FBWU), in Aiken, South Carolina, which was chosen in accordance with CERCLA, as amended by SARA, and, to the extent practical, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on the Administrative Record File for this specific RCRA/CERCLA site.
Date:
June 13, 2002
Creator:
Fraley, S.
Object Type:
Report
System:
The UNT Digital Library
Vacuum Furnace Brazing Open Cell Reticulated Foam to Stainless Steel Tubing
This paper describes the intended application and development effort required to braze the copper foam to the stainless steel tubing.
Date:
September 13, 2002
Creator:
Korinko, P.S.
Object Type:
Article
System:
The UNT Digital Library
Simulations of the Neutral-beam-induced Rotation, Radial Electric Field, and Flow Shearing Rate in Next-step Burning Plasmas
Toroidal rotation of plasmas in present tokamaks is beneficial for increasing the stability to wall-induced MHD and appears to reduce the anomalous transport associated with micro-turbulence. This paper calculates the toroidal rotation expected from neutral-beam injection in the proposed FIRE and ITER-FEAT tokamak reactors. Self-consistent burning plasmas for these tokamaks have been constructed using the TRANSP plasma analysis code. Neutral-beam injection has been proposed for FIRE and ITER-FEAT. The neutral-beam-induced torques are computed, and assumptions for the anomalous transport of toroidal angular momentum are used to calculate the toroidal rotation profiles. The central Mach numbers are about 3-8%. The ratio of the rotation speed to the Alfvin speed is less than 1%. Assuming neoclassical poloidal rotation and force balance, the radial electric field and flow shearing rate are calculated. Peak shearing rates near the outboard edge are in the 10-100 krad/s range.
Date:
August 13, 2002
Creator:
Budny, R.V.
Object Type:
Report
System:
The UNT Digital Library
Physics reach of BTeV
BTeV is a collider program at the Fermilab Tevatron dedicated to the study of CP violation, mixing, and rare decays in beauty and charm hadrons. The detector is a forward spectrometer sited at the C-Zero interaction region.
Date:
December 13, 2002
Creator:
Kasper, Penelope A
Object Type:
Article
System:
The UNT Digital Library
Application of joint inversion for mapping fluid parameters
A two-dimensional joint inversion technique, based on a least-squares criterion of the data misfit and model smoothness, has been developed using electromagnetic (EM) and seismic traveltime data to assess the feasibility of directly inverting for hydrological parameters, such as fluid electrical conductivity, porosity, and saturation. This is accomplished by relating hydrological parameters to geophysical properties with the help of the empirical Archie's law and the Wyllie time average equation. While the latter links the underground seismic wave velocity and subsurface media porosity, the former relates the bulk formation conductivity to hydrological parameters such as fluid conductivity and porosity. Direct joint inversion using various geophysical data also reduces the non-uniqueness of the problem since common parameters are involved, as is the porosity related to both seismic traveltime and magnetic field. This newly developed joint inversion algorithm has been applied to a set of crosshole seismic and EM field data provided by Chevron as part of the Lost Hills CO{sub 2} pilot project in Southern California. Both EM and seismic pre- and post-injection data were evaluated in terms of hydrological parameters using general empirical relationships derived from logging data. The results show that the injection has decreased the water saturation and bulk …
Date:
September 13, 2002
Creator:
Tseng, Hung-Wen & Lee, Ki Ha
Object Type:
Article
System:
The UNT Digital Library
Simulations of Temperatures in Burning Tokamak Plasmas using the GLF23 Model in the TRANSP Code
The GLF23 prediction model, incorporated in the TRANSP plasma analysis code, is used to predict temperatures for burning plasmas in the proposed FIRE and ITER-FEAT tokamaks. Flat electron density profiles with various central values are assumed. Scaling of the fusion power P(subscript)dt and gain Q(subscript)dt with density (subscript)and pedestal temperature are given. Helium ash transport and sawtooth effect Pdt in long duration ITER-FEAT plasmas.
Date:
August 13, 2002
Creator:
Budny, R.V.
Object Type:
Report
System:
The UNT Digital Library
Hybrid electric vehicle technology assessment : methodology, analytical issues, and interim results.
This report presents the results of the first phase of Argonne National Laboratory's (ANL's) examination of the costs and energy impacts of light-duty hybrid electric vehicles (HEVs). We call this research an HEV Technology Assessment, or HEVTA. HEVs are vehicles with drivetrains that combine electric drive components (electric motor, electricity storage) with a refuelable power plant (e.g., an internal combustion engine). The use of hybrid drivetrains is widely considered a key technology strategy in improving automotive fuel efficiency. Two hybrid vehicles--Toyota's Prius and Honda's Insight--have been introduced into the U.S. market, and all three auto industry participants in the Partnership for a New Generation of Vehicles (PNGV) have selected hybrid drivetrains for their prototype vehicles.
Date:
March 13, 2002
Creator:
Plotkin, S.; Santini, D.; Vyas, A.; Anderson, J.; Wang, M.; Bharathan, D. et al.
Object Type:
Report
System:
The UNT Digital Library
SCALING PROPERTIES OF THE TRANSVERSE MASS SPECTRA.
Motivated from the formation of an initial state of gluon-saturated matter, we discuss scaling relations for the transverse mass spectra at BNL's Relativistic Heavy-Ion Collider (RHIC). We show on linear plots, that the transverse mass spectra for various hadrons can be described by an universal function in m{sub t}. The transverse mass spectra for different centralities can be rescaled into each other. Finally, we demonstrate that m{sub t}-scaling is also present in proton-antiproton collider data and compare it to m{sub t}-scaling at RHIC.
Date:
January 13, 2002
Creator:
Schaffner-Bielich, J.; Kharzeev, D.; Mclerran, L. & Venugopalan, R.
Object Type:
Article
System:
The UNT Digital Library
Large Scale Vitrification of 241-AN-102 (Envelope C) Sample
The work presented in this technical report supports use of the technology being proposed by RPP-WTP personnel for pretreatment and immobilization of pretreated Hanford tank 241-AN-102 waste.
Date:
December 13, 2002
Creator:
Crawford, C.
Object Type:
Report
System:
The UNT Digital Library
Fluid Assisted Compaction and Deformation of Reservoir Lithologies
The compaction and diagenesis of sandstones that form reservoirs to hydrocarbons depend on mechanical compaction processes, fluid flow at local and regional scales, and chemical processes of dissolution, precipitation and diffusional solution transport. The compaction and distortional deformation of quartz aggregates exposed to reactive aqueous fluids have been investigated experimentally at varying critical and subcritical stress states and time scales. Pore fluid compositions and reaction rates during deformation have been measured and compared with creep rates. Relative contributions of mechanical and chemical processes to deformation and pore structure evolution have been evaluated using acoustic emission (AE) measurements and scanning electron microscope (SEM) observations. At the subcritical conditions investigated, creep rates and acoustic emission rates fit transient logarithmic creep laws. Based on AE and SEM observations, we conclude that intragranular cracking and grain rearrangement are the dominant strain mechanisms. Specimens show little evidence of stress-enhanced solution transfer. At long times under wet conditions, the dominant strain mechanism gradually shifts from critical cracking at grain contacts with high stress concentrations to fluid-assisted sub-critical cracking.
Date:
February 13, 2002
Creator:
Kronenberg, A. K.; Chester, F. M.; Chester, J. S.; Hajash, A.; He, W.; Karner, S. et al.
Object Type:
Report
System:
The UNT Digital Library
Hydraulic performance of a 5-cm CINC contactor for caustic-side solvent extraction.
The hydraulic performance of a 5-cm centrifugal contactor from Costner Industries Nevada Corporation (CINC) was measured for both one- and two-phase flow. Flow conditions and test liquids as well as the liquid height in the annular mixing zone and the occurrence of discontinuous (slug) flow in the interstage lines are reported. Results are compared with earlier results obtained using 2- and 4-cm contactors made at Argonne National Laboratory. In each case, one-phase flow tests can be used to predict behavior in two-phase flow. This makes the one-phase flow test a quality control tool for evaluating contactor rotors as they are manufactured. These results indicate that the 5-cm contactor works in the same way as the 2- and 4-cm contactors.
Date:
August 13, 2002
Creator:
Leonard, R. A.; Regalbuto, M. C.; Aase, S. B.; Arafat, H. A. & Falkenburg, J. R.
Object Type:
Report
System:
The UNT Digital Library
Development of Liquid-Vapor Core Reactors with MHD Generator for Space Power and Propulsion Applications
Any reactor that utilizes fuel consisting of a fissile material in a gaseous state may be referred to as a gaseous core reactor (GCR). Studies on GCRs have primarily been limited to the conceptual phase, mostly due to budget cuts and program cancellations in the early 1970's. A few scientific experiments have been conducted on candidate concepts, primarily of static pressure fissile gas filling a cylindrical or spherical cavity surrounded by a moderating shell, such as beryllium, heavy water, or graphite. The main interest in this area of nuclear power generation is for space applications. The interest in space applications has developed due to the promise of significant enhancement in fuel utilization, safety, plant efficiency, special high-performance features, load-following capabilities, power conversion optimization, and other key aspects of nuclear power generation. The design of a successful GCR adapted for use in space is complicated. The fissile material studied in the pa st has been in a fluorine compound, either a tetrafluoride or a hexafluoride. Both of these molecules have an impact on the structural material used in the making of a GCR. Uranium hexafluoride as a fuel allows for a lower operating temperature, but at temperatures greater than 900K becomes …
Date:
August 13, 2002
Creator:
Anghaie, Samim
Object Type:
Report
System:
The UNT Digital Library