A study of turbulence in an evolving stable atmospheric boundary layer using large-eddy simulation (open access)

A study of turbulence in an evolving stable atmospheric boundary layer using large-eddy simulation

A study is made of the effects of stable stratification on the fine-scale features of the flow in an evolving stable boundary layer (SBL). Large-eddy simulation (LES) techniques are used so that spatially and temporally varying and intermittent features of the turbulence can be resolved; traditional Reynolds-averaging approaches are not well suited to this. The LES model employs a subgrid turbulence model that allows upscale energy transfer (backscatter) and incorporates the effects of buoyancy. The afternoon, evening transition, and nighttime periods are simulated. Highly anisotropic turbulence is found in the developed SBL, with occasional periods of enhanced turbulence. Energy backscatter occurs in a fashion similar to that found in DNS, and is an important capability in LES of the SBL. Coherent structures are dominant in the SBL, as the damping of turbulent energy occurs more at the smaller, less organized scales.
Date: May 1, 1999
Creator: Cederwall, R & Street, R L
System: The UNT Digital Library
Direct flow in 10.8 GeV/nucleon Au+Au collisions measured in experiment E917 at the AGS. (open access)

Direct flow in 10.8 GeV/nucleon Au+Au collisions measured in experiment E917 at the AGS.

Analysis of directed flow observable for protons and pions from Au+Au collisions at 10.8 GeV/nucleon from experiment E917 at the AGS is presented. Using a Fourier series expansion, the first Fourier component, {nu}{sub 1},was extracted as a function of rapidity for mid-central collisions (17-24%). Clear evidence for positive directed flow is found in the proton data, and a weak, possibly negative directed flow signal is observed for {pi}{sup +} and {pi}{sup {minus}}.
Date: May 19, 1999
Creator: Back, B. B.; Betts, R. R.; Britt, H. C.; Chang, J.; Chang, W. C.; Gillitzer, A. et al.
System: The UNT Digital Library
Completion of the INEEL's WERF Incinerator Trial Burn (open access)

Completion of the INEEL's WERF Incinerator Trial Burn

This paper describes the successes and challenges associated with Resource Conservation and Recovery Act (RCRA) permitting of the Idaho National Engineering and Environmental Laboratory's (INEEL) Waste Experimental Reduction Facility (WERF) hazardous and mixed waste incinerator. Topics to be discussed include facility modifications and problems, trial burn results and lessons learned in each of these areas. In addition, a number of challenges remain including completion and final issue of the RCRA Permit and implementation of all the permit requirements. Results from the trial burn demonstrated that the operating conditions and procedures will result in emissions that are satisfactorily protective of human health, the environment, and are in compliance with Federal and State regulations.
Date: May 1, 1999
Creator: Branter, C. K.; Conley, D. A.; Moser, D. R. & Corrigan, S. J.
System: The UNT Digital Library
Plutonium and surrogate fission products in a composite ceramic waste form. (open access)

Plutonium and surrogate fission products in a composite ceramic waste form.

Argonne National Laboratory is developing a ceramic waste form to immobilize salt containing fission products and transuranic elements. Preliminary results have been presented for ceramic waste forms containing surrogate fission products such as cesium and the lanthanides. In this work results from scanning electron microscopy/energy dispersive spectroscopy and x-ray diffraction are presented in greater detail for ceramic waste forms containing surrogate fission products. Additionally, results for waste forms containing plutonium and surrogate fission products are presented. Most of the surrogate fission products appear to be silicates or aluminosilicates whereas the plutonium is usually found in an oxide form. There is also evidence for the presence of plutonium within the sodalite phase although the chemical speciation of the plutonium is not known.
Date: May 19, 1999
Creator: Esh, D. W.; Frank, S. M.; Goff, K. M.; Johnson, S. G.; Moschetti, T. L. & O'Holleran, T.
System: The UNT Digital Library
Gamma-ray array physics. (open access)

Gamma-ray array physics.

In this contribution I am going to discuss the development of large arrays of Compton Suppressed, High Purity Germanium (HpGe) detectors and the physics that has been, that is being, and that will be done with them. These arrays and their science have dominated low-energy nuclear structure research for the last twenty years and will continue to do so in the foreseeable future. John Sharpey Schafer played a visionary role in convincing a skeptical world that the development of these arrays would lead to a path of enlightenment. The extent to which he succeeded can be seen both through the world-wide propagation of ever more sophisticated devices, and through the world-wide propagation of his students. I, personally, would not be working in research if it were not for Johns inspirational leadership. I am eternally grateful to him. Many excellent reviews of array physics have been made in the past which can provide detailed background reading. The review by Paul Nolan, another ex-Sharpey Schafer student, is particularly comprehensive and clear.
Date: May 25, 1999
Creator: Lister, C. J.
System: The UNT Digital Library
Aqueous biphasic systems for metal separations : a microcalorimetric analysis of polymer/salt interactions. (open access)

Aqueous biphasic systems for metal separations : a microcalorimetric analysis of polymer/salt interactions.

Certain radionuclide ions (e.g., TcO{sub 4}{sup 16}) exhibit unusually strong Affinities toward the polymer-rich phase in aqueous biphase systems generated by combinations of salt solutions with polymers such as poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG). Thus, aqueous polymer phases could potentially be used to selectively extract these ions during pretreatment of radioactive tank wastes at Hanford. To help develop a fundamental understanding of the interactions between various ions and polymers in aqueous solution, interaction enthalpies between sodium perrhenate and a random copolymer of PEG and PPG (UCON-50) were measured by microcalorimetric titration. An entropy compensation effect was observed in this system in which changes in enthalpic interactions were balanced by entropy changes such that the interaction free energy remained constant and approximately equal to zero.
Date: May 3, 1999
Creator: Chaiko, D. J.; Hatton, T. A. & Zaslavsky, B.
System: The UNT Digital Library
Scale up issues involved with the ceramic waste form : ceramic-container interactions and ceramic cracking quantification. (open access)

Scale up issues involved with the ceramic waste form : ceramic-container interactions and ceramic cracking quantification.

Argonne National Laboratory is developing a process for the conditioning of spent nuclear fuel to prepare the material for final disposal. Two waste streams will result from the treatment process, a stainless steel based form and a ceramic based form. The ceramic waste form will be enclosed in a stainless steel container. In order to assess the performance of the ceramic waste form in a repository two factors must be examined, the surface area increases caused by waste form cracking and any ceramic/canister interactions that may release toxic material. The results indicate that the surface area increases are less than the High Level Waste glass and any toxic releases are below regulatory limits.
Date: May 3, 1999
Creator: Bateman, K. J.; DiSanto, T.; Goff, K. M.; Johnson, S. G.; O'Holleran, T. & Riley, W. P., Jr.
System: The UNT Digital Library
Organization and management of the plant safety evaluation of the VVER-440/230 units at Novovoronezh. (open access)

Organization and management of the plant safety evaluation of the VVER-440/230 units at Novovoronezh.

As part of the Soviet-Designed Reactor Safety (SDRS) element of the International Nuclear Safety Program (INSP), the US Department of Energy (US DOE) is funding a plant safety evaluation (PSE) project for the Novovoronezh Nuclear Power Plant (NvNPP). The Novovoronezh PSE Project is a multi-faceted project with participants from sixteen different international organizations from five different countries scattered across eleven time zones. The purpose of this project is to provide a thorough Probabilistic Risk Analysis (PRA) and Deterministic Safety Analysis (DSA) for Units 3 and 4 of the NvNPP. In addition, this project provides assistance to the operation organizations in meeting their international commitments in support of safety upgrades, and their regulatory requirements for the conduct of safety analyses. Managing this project is a complex process requiring numerous management tools, constant monitoring, and effective communication skills. Employing management tools to resolve unanticipated problems one of the keys to project success. The overall scope, programmatic context, objectives, project interactions, communications, practical hindrances, and lessons learned from the challenging performance of the PSE project are summarized in this paper.
Date: May 13, 1999
Creator: Afshar, C. M.; Pizzica, P.; Puglia, W. J. & Rozin, V.
System: The UNT Digital Library
Language interoperability for high-performance parallel scientific components (open access)

Language interoperability for high-performance parallel scientific components

With the increasing complexity and interdisciplinary nature of scientific applications, code reuse is becoming increasingly important in scientific computing. One method for facilitating code reuse is the use of components technologies, which have been used widely in industry. However, components have only recently worked their way into scientific computing. Language interoperability is an important underlying technology for these component architectures. In this paper, we present an approach to language interoperability for a high-performance parallel, component architecture being developed by the Common Component Architecture (CCA) group. Our approach is based on Interface Definition Language (IDL) techniques. We have developed a Scientific Interface Definition Language (SIDL), as well as bindings to C and Fortran. We have also developed a SIDL compiler and run-time library support for reference counting, reflection, object management, and exception handling (Babel). Results from using Babel to call a standard numerical solver library (written in C) from C and Fortran show that the cost of using Babel is minimal, where as the savings in development time and the benefits of object-oriented development support for C and Fortran far outweigh the costs.
Date: May 18, 1999
Creator: Elliot, N; Kohn, S & Smolinski, B
System: The UNT Digital Library
POLARIZED PROTONS TRACKING IN THE AGS AND RHIC. (open access)

POLARIZED PROTONS TRACKING IN THE AGS AND RHIC.

A code, SPINK, to track polarized particles in a circular accelerator, in particular RHIC [1], is been used to: find conditions for safely crossing depolarizing resonances, using Siberian Snakes; find the best conditions to match the spin of the injected beam to the ring lattice; study the operation of Spin Rotators and study the beam-beam effects in a polarized proton collider.
Date: May 20, 1999
Creator: Luccio, A. U.
System: The UNT Digital Library
Comparison of the corrosion behaviors of the glass-bonded sodalite ceramic waste form and reference HLW glasses. (open access)

Comparison of the corrosion behaviors of the glass-bonded sodalite ceramic waste form and reference HLW glasses.

A glass-bonded sodalite ceramic waste form is being developed for the long-term immobilization of salt wastes that are generated during spent nuclear fuel conditioning activities. A durable waste form is prepared by hot isostatic pressing (HIP) a mixture of salt-loaded zeolite powders and glass frit. A mechanistic description of the corrosion processes is being developed to support qualification of the CWF for disposal. The initial set of characterization tests included two standard tests that have been used extensively to study the corrosion behavior of high level waste (HLW) glasses: the Material Characterization Center-1 (MCC-1) Test and the Product Consistency Test (PCT). Direct comparison of the results of tests with the reference CWF and HLW glasses indicate that the corrosion behaviors of the CWF and HLW glasses are very similar.
Date: May 6, 1999
Creator: Ebert, W. L. & Lewis, M. A.
System: The UNT Digital Library
The spent fuel standard - does the can-in-canister concept for plutonium immobilization measure up? (open access)

The spent fuel standard - does the can-in-canister concept for plutonium immobilization measure up?

Critics continue to question whether or not the can-in-canister concept for immobilization and disposal of surplus plutonium meets the ''Spent Fuel Standard.'' Following this standard would make this plutonium roughly as ''inaccessible for weapons use as the much larger and growing quantity of plutonium that exists in spent fuel from commercial reactors.'' These critics take a narrower view of the ''Spent Fuel Standard'' than was intended in the National Academy reports, rather than considering the total effective barrier. This paper directly compares retrieval and recovery of plutonium from a can-in-canister to a spent fuel assembly. The conclusion from this study, as from earlier studies, is that the plutonium in the can-in-canister form is less accessible and less attractive to a potential proliferate than the plutonium that exists in spent fuel from commercial reactors.
Date: May 27, 1999
Creator: Gray, L W & McKibben, J M
System: The UNT Digital Library
Summary of experimental electroweak physics. (open access)

Summary of experimental electroweak physics.

Progress continues on many fronts of experimental testing of electroweak symmetry breaking. Updates were presented on LEP, SLC, Brookhaven g-2 ring, Tevatron Collider, HERA, CESR and Tevatron neutrino experiments. Perhaps most exciting is the Higgs search at LEP2, complementing the indirect constraints. However, the standard model with one Higgs doublet remains viable.
Date: May 3, 1999
Creator: Nodulman, L.
System: The UNT Digital Library
Controlled densification of mullite for composite applications. (open access)

Controlled densification of mullite for composite applications.

As part of an effort to fabricate oxide-based fibrous monolithic ceramics, sintering of mullite has been examined. The effects of Y{sub 2}O{sub 3} additions on sinterability of sol-gel-derived mullite and on the resulting microstructure were evaluated over a range of compositions, sintering times, and temperatures. Electron microscopy, X-ray diffraction, differential thermal analysis, and density measurements indicated that the Y{sub 2}O{sub 3} additions promoted densification through formation of a Y-Si-Al-O liquid phase. This phase tended to solidify as a glass during normal processing, but could be crystallized by a two-step annealing process at 1300 and 1200 C. The four-point flexural strengths of mullite and mullite-5 Wt.% Y{sub 2}O{sub 3} were also examined.
Date: May 19, 1999
Creator: Cruse, T. A.
System: The UNT Digital Library
Liquid metal reactor deactivation as applied to the experimental breeder reactor - II. (open access)

Liquid metal reactor deactivation as applied to the experimental breeder reactor - II.

The Experimental Breeder Reactor-II (EBR-II) at Argonne National Laboratory-West (ANL-W) was shutdown in September, 1994. This sodium cooled reactor had been in service since 1964, and by the US Department of Energy (DOE) mandate, was to be placed in an industrially and radiologically safe condition for ultimate decommissioning. The deactivation of a liquid metal reactor presents unique concerns. The first major task associated with the project was the removal of all fueled assemblies. In addition, sodium must be drained from systems and processed for ultimate disposal. Residual quantities of sodium remaining in systems must be deactivated or inerted to preclude future hazards associated with pyrophoricity and generation of potentially explosive hydrogen gas. A Sodium Process Facility (SPF) was designed and constructed to react the elemental sodium from the EBR-II primary and secondary systems to sodium hydroxide for disposal. This facility has a design capacity to allow the reaction of the complete inventory of sodium at ANL-W in less than two years. Additional quantities of sodium from the Fermi-1 reactor are also being treated at the SPF.
Date: May 28, 1999
Creator: Earle, O. K.; Michelbacher, J. A.; Pfannenstiel, D. F. & Wells, P. B.
System: The UNT Digital Library
Status of the new muon (g - 2) experiment. (open access)

Status of the new muon (g - 2) experiment.

The new muon (g - 2) experiment is now fully operational The goal of the experiment is to obtain a relative error on (g - 2) of {+-}O.35 ppm to measure the electroweak contribution for the first time, and to observe, or place stringent limits on physics beyond the standard model which can contribute to (g - 2). A brief status report is presented.
Date: May 3, 1999
Creator: Carey, R. M.; Earle, W.; Efstathiadis, E.; Hare, M. F.; Collaboration, MUON (g - 2); Nodulman, L. et al.
System: The UNT Digital Library
Considerations for advanced reactor design based on EBR-II experience. (open access)

Considerations for advanced reactor design based on EBR-II experience.

The long-term success of the Experimental Breeder Reactor-II (EBR-II) provides several insights into fundamental characteristics and design features of a nuclear generating station that enhance safety, operability, and maintainability. Some of these same characteristics, together with other features, offer the potential for operational lifetimes well beyond the current licensing time frame, and improved reliability that could potentially reduce amortized capital costs as well as overall operation and maintenance costs if incorporated into advanced plant designs. These features and characteristics are described and the associated benefits are discussed.
Date: May 26, 1999
Creator: King, R. W.
System: The UNT Digital Library
Toward a fourth-generation light source. (open access)

Toward a fourth-generation light source.

Historically, x-ray research has been propelled by the existence of urgent and compelling scientific questions and the push of powerful and exquisite source technology. These two factors have gone hand in hand since Rontgen discovered x-rays. Here we review the progress being made with existing third-generation synchrotron-radiation light sources and the prospects for a fourth-generation light source with dramatically improved laser-like beam characteristics. The central technology for high-brilliance x-ray beams is the x-ray undulator, a series of alternating-pole magnets situated above and below the particle beam. When the particle beam is oscillated by the alternating magnetic fields, a set of. interacting and interfering wave fronts is produced, which leads to an x-ray beam with extraordinary properties. Third-generation sources of light in the hard x-ray range have been constructed at three principal facilities: the European Synchrotrons Radiation Facility (ESRF) in France; the Super Photon Ring 8-GeV (or Spring-8) in Japan; and the Advanced Photon Source (APS) in the US. Undulator technology is also used on a number of low-energy machines for radiation in the ultraviolet and soft x-ray regimes. At the APS, these devices exceed all of our original expectations for beam brilliance, tunability, spectral range, and operational flexibility. Shown in …
Date: May 3, 1999
Creator: Moncton, D. E.
System: The UNT Digital Library
Thermal management concepts for higher efficiency heavy vehicles. (open access)

Thermal management concepts for higher efficiency heavy vehicles.

Thermal management is a cross-cutting technology that directly or indirectly affects engine performance, fuel economy, safety and reliability, aerodynamics, driver/passenger comfort, materials selection, emissions, maintenance, and component life. This review paper provides an assessment of thermal management for large trucks, particularly as it impacts these features. Observations arrived at from a review of the state of the art for thermal management for over-the-road trucks are highlighted and commented on. Trends in the large truck industry, pertinent engine truck design and performance objectives, and the implications of these relative to thermal management, are presented. Finally, new thermal management concepts for high efficiency vehicles are described.
Date: May 19, 1999
Creator: Wambsganss, M. W.
System: The UNT Digital Library
Phosphate ceramic solidification and stabilization of cesium-containing crystalline silicotitanate resins. (open access)

Phosphate ceramic solidification and stabilization of cesium-containing crystalline silicotitanate resins.

This paper reports on the fabrication and testing of magnesium potassium phosphate (MKP)-bonded cesium-loaded crystalline silicotitanate (CST) resins. Typical waste loading of CST resins in the final waste forms was 50 wt.%. Physical and chemical characterization of the MKP materials has shown them to be physically, chemically, and mineralogically stable. Long-term durability studies (using the AN 16.1 standard test) showed a leachability index of {approx}18 for cesium in the phosphate matrix when exposed to deionized water under ambient and elevated temperatures. Leaching of cesium was somewhat higher than in glass waste forms as per PCT and MCC-1 tests. MKP-based final waste forms showed no significant weight changes after exposure to aqueous media for {approx}90 days, indicating the highly insoluble nature of the phosphate matrix. In addition, durability of the CST-MKP waste forms was further established by freeze-thaw cycling tests.
Date: May 11, 1999
Creator: Langton, C. A.
System: The UNT Digital Library
Dynamic Holographic Lock-In Imaging of Ultrasonic Waves (open access)

Dynamic Holographic Lock-In Imaging of Ultrasonic Waves

A laser imaging approach is presented that utilizes the adaptive property of photorefractive materials to produce a real-time measurement of ultrasonic traveling wave surface displacement and phase in all planar directions simultaneously without scanning. The imaging method performs optical lock-in operation. A single antisymmetric Lamb wave mode image produces direct quantitative determination of the phase velocity in all planar directions showing plate stiffness anisotropy. Excellent agreement was obtained with modeling calculations of the phase velocity in all planar directions for an anisotropic sheet material. The approach functions with diffusely scattering surfaces, subnanometer motions and at frequencies from Hz to GHz.
Date: May 1, 1999
Creator: Telschow, K. L.; Datta, S. K. & Deason, V. A.
System: The UNT Digital Library
Fracture toughness measurements on a glass bonded sodalite high-level waste form. (open access)

Fracture toughness measurements on a glass bonded sodalite high-level waste form.

The electrometallurgical treatment of metallic spent nuclear fuel produces two high-level waste streams; cladding hulls and chloride salt. Argonne National Laboratory is developing a glass bonded sodalite waste form to immobilize the salt waste stream. The waste form consists of 75 Vol.% crystalline sodalite (containing the salt) with 25 Vol.% of an ''intergranular'' glassy phase. Microindentation fracture toughness measurements were performed on representative samples of this material using a Vickers indenter. Palmqvist cracking was confirmed by post-indentation polishing of a test sample. Young's modulus was measured by an acoustic technique. Fracture toughness, microhardness, and Young's modulus values are reported, along with results from scanning electron microscopy studies.
Date: May 19, 1999
Creator: DiSanto, T.; Goff, K. M.; Johnson, S. G. & O'Holleran, T. P.
System: The UNT Digital Library
Round-robin testing of a standard material for acceptance testing of low-activity radioactive waste products. (open access)

Round-robin testing of a standard material for acceptance testing of low-activity radioactive waste products.

A round robin test program was conducted with a glass that was developed for use as a standard test material for acceptance testing of low-activity waste glasses made with Hanford tank wastes. The program was conducted to measure the between-laboratory reproducibility of composition analysis and durability test results. Participants were free to select the methods used to analyze the glass composition. The durability tests closely followed the Product Consistency Test (PCT) Method A, except that tests were conducted at both 40 and 90 C, and parallel tests with a reference glass were not required. Samples that had been crushed, sieved, and washed to remove fines were provided to participants for tests and analyses. The results are presented in this paper. While the results are still being analyzed, the reproducibility of both the composition and PCTs results compare favorably with the results of round robins conducted with other glasses.
Date: May 13, 1999
Creator: Ebert, W. L.
System: The UNT Digital Library
Development and application of NDE methods for monolithic and continuous fiber ceramic matrix composites. (open access)

Development and application of NDE methods for monolithic and continuous fiber ceramic matrix composites.

Monolithic structural ceramics and continuous fiber ceramic matrix composites (CMCs) are being developed for application in many thermally and chemically aggressive environments where structural reliability is paramount. We have recently developed advanced nondestructive evaluation (NDE) methods that can detect distributed ''defects'' such as density gradients and machining-induced damage in monolithic materials, as well as delamination, porosity, and throughwall cracks, in CMC materials. These advanced NDE methods utilize (a) high-resolution, high-sensitivity thermal imaging; (b) high-resolution X-ray imaging; (c) laser-based elastic optical scattering; (d) acoustic resonance; (e) air-coupled ultrasonic methods; and (f) high-sensitivity fluorescent penetrant technology. This paper discusses the development and application of these NDE methods relative to ceramic processing and ceramic components used in large-scale industrial gas turbines and hot gas filters for gas stream particulate cleanup.
Date: May 21, 1999
Creator: Ellingson, W. A.
System: The UNT Digital Library