[Studies of non-linear dynamics of dissipative systems]. [Final report, April 1, 1988--October 31, 1989] (open access)

[Studies of non-linear dynamics of dissipative systems]. [Final report, April 1, 1988--October 31, 1989]

In the period of this grant I worked on three main areas: (1) Symmetries in inviscid flow equations in one, two, and three dimensions and related nonlinear stability theorems for these flows; (2) applications of Hamiltonian mechanics to the problems of shallow water equations and internal wave dynamics in oceanic flows; and, (3) analysis of signals from chaotic systems with an eye toward learning how to build models of chaotic systems in nature.
Date: September 10, 1990
Creator: Abarbanel, D. I.
Object Type: Report
System: The UNT Digital Library
(Studies of non-linear dynamics of dissipative systems) (open access)

(Studies of non-linear dynamics of dissipative systems)

In the period of this grant I worked on three main areas: (1) Symmetries in inviscid flow equations in one, two, and three dimensions and related nonlinear stability theorems for these flows; (2) applications of Hamiltonian mechanics to the problems of shallow water equations and internal wave dynamics in oceanic flows; and, (3) analysis of signals from chaotic systems with an eye toward learning how to build models of chaotic systems in nature.
Date: September 10, 1990
Creator: Abarbanel, D.I.
Object Type: Report
System: The UNT Digital Library
Radiative higgs boson decays H {yields} f{anti f}{gamma} (open access)

Radiative higgs boson decays H {yields} f{anti f}{gamma}

Higgs boson radiative decays of the form H {r_arrow} f{ovr f}{gamma} are calculated in the Standard Model using the complete one-loop expressions for the decay amplitudes. Contributions to the radiative width from leptons and light quarks are given. We also present e{ovr e} invariant mass distributions for H {r_arrow} e{ovr e}{gamma}, which illustrate the importance of the photon pole contribution and the effects of the box diagrams. 4 refs., 6 figs.
Date: October 10, 1996
Creator: Abbasabadi, A.; Bowser-Chao, D.; Repko, W.W. & Dicus, D.A.
Object Type: Report
System: The UNT Digital Library
A Preliminary measurement of the gluon splitting rate into b\bar{b} pairs in hadronic Z0 decays (open access)

A Preliminary measurement of the gluon splitting rate into b\bar{b} pairs in hadronic Z0 decays

We present a measurement of the rate of gluon splitting into bottom quarks, g --> b anti-b, in hadronic Z<sup>0</sup> decays collected by SLD from 1996 to 1998. The analysis was performed by looking for secondary bottom production in 4-jet events of any primary avor. A topological vertex mass technique was used to tag the two jets with the smallest angle between them as b/anti-b. We obtained a rate of g --> b anti-b per hadronic event to be (3.07 ± 0.71(stat:) ± 0.66(syst:)) × 10&sup3; (preliminary).
Date: June 10, 1999
Creator: Abe, Toshinori
Object Type: Report
System: The UNT Digital Library
III-Nitride Dry Etching - Comparison of Inductively Coupled Plasma Chemistries (open access)

III-Nitride Dry Etching - Comparison of Inductively Coupled Plasma Chemistries

A systematic study of the etch characteristics of GaN, AlN and InN has been performed with boron halides- (BI{sub 3} and BBr{sub 3}) and interhalogen- (ICl and IBr) based Inductively Coupled Plasmas. Maximum etch selectivities of -100:1 were achieved for InN over both GaN and AlN in the BI{sub 3} mixtures due to the relatively high volatility of the InN etch products and the lower bond strength of InN. Maximum selectivies of- 14 for InN over GaN and >25 for InN over AlN were obtained with ICl and IBr chemistries. The etched surface morphologies of GaN in these four mixtures are similar or better than those of the control sample.
Date: November 10, 1998
Creator: Abernathy, C.R.; Cho, H.; Donovan, S.M.; Hahn, Y-B.; Han, J.; Hays, D.C. et al.
Object Type: Article
System: The UNT Digital Library
A novel approach to highly dispersing catalytic materials in coal for gasification. Ninth quarterly report, October 1, 1991--December 31, 1991 (open access)

A novel approach to highly dispersing catalytic materials in coal for gasification. Ninth quarterly report, October 1, 1991--December 31, 1991

This project seeks to develop a technique, based on coal surface properties, for highly dispersing catalysts in coal for gasification and to investigate the potential of using potassium carbonate and calcium acetate mixtures as catalysts for coal gasification. The lower cost and higher catalytic activity of the latter compound will produce economic benefits by reducing the amount of K{sub 2}CO{sub 3} required for high coal char reactivities. As was shown in previous reports, coal loading with potassium or calcium at different pHs produced CO{sub 2} gasification activities which increased in the order pH 6 > pH 10 {much_gt} pH 1. The current report shows that a similar trend was obtained when calcium and potassium were simultaneously loaded and char reaction times were less than about 75 min. Beyond this time, the coal impregnated with catalyst at pH 1 became more reactive, reaching 100% conversion after 1.5h. X-ray diffraction analysis suggest that the catalysts are well dispersed around pH 1 and 6 whereas reduced dispersion as obtained at pH 10. The reactivities are independent of the surface areas of the coals.
Date: February 10, 1992
Creator: Abotsi, G. M. K. & Bota, K. B.
Object Type: Report
System: The UNT Digital Library
A novel approach to highly dispersing catalytic materials in coal for gasification (open access)

A novel approach to highly dispersing catalytic materials in coal for gasification

This project seeks to develop a technique, based on coal surface properties, for highly dispersing catalysts in coal for gasification and to investigate the potential of using potassium carbonate and calcium acetate mixtures as catalysts for coal gasification. The lower cost and higher catalytic activity of the latter compound will produce economic benefits by reducing the amount of K{sub 2}CO{sub 3} required for high coal char reactivities. As was shown in previous reports, coal loading with potassium or calcium at different pHs produced CO{sub 2} gasification activities which increased in the order pH 6 > pH 10 {much gt} pH 1. The current report shows that a similar trend was obtained when calcium and potassium were simultaneously loaded and char reaction times were less than about 75 min. Beyond this time, the coal impregnated with catalyst at pH 1 became more reactive, reaching 100% conversion after 1.5h. X-ray diffraction analysis suggest that the catalysts are well dispersed around pH 1 and 6 whereas reduced dispersion as obtained at pH 10. The reactivities are independent of the surface areas of the coals.
Date: February 10, 1992
Creator: Abotsi, G.M.K. & Bota, K.B.
Object Type: Report
System: The UNT Digital Library
Analysis of Ignition Testing on K-West Basin Fuel (open access)

Analysis of Ignition Testing on K-West Basin Fuel

Approximately 2100 metric tons of spent nuclear fuel (SNF) discharged from the N-Reactor have been stored underwater at the K-Basins in the 100 Area of the Hanford Site. The spent fuel has been stored in the K-East Basin since 1975 and in the K-West Basin since 1981. Some of the SNF elements in these basins have corroded because of various breaches in the Zircaloy cladding that occurred during fuel discharge operations and/or subsequent handling and storage in the basins. Consequently, radioactive material in the fuel has been released into the basin water, and water has leaked from the K-East Basin into the soil below. To protect the Columbia River, which is only 380 m from the basins, the SNF is scheduled to be removed and transported for interim dry storage in the 200 East Area, in the central portion of the Site. However, before being shipped, the corroded fuel elements will be loaded into Multi-Canister OverPacks and conditioned. The conditioning process will be selected based on the Integrated Process Strategy (IPS) (WHC 1995), which was prepared on the basis of the dry storage concept developed by the Independent Technical Assessment (ITA) team (ITA 1994).
Date: August 10, 1999
Creator: Abrefah, J.; Huang, F.H.; Gerry, W.M.; Gray, W.J.; Marschman, S.C. & Thornton, T.A.
Object Type: Report
System: The UNT Digital Library
Analysis of Ignition Testing on K-West Basin Fuel (open access)

Analysis of Ignition Testing on K-West Basin Fuel

Ignition tests and analyses of damage/corroded N-Reactor spent nuclear fuel (SNF) were performed by Pacific Northwest National Laboratory as part of a series of studies on the deteriorating spent fuel in the Hanford K-Basins. The ignition temperature tests were conducted to assess tie pyrophoric properties of selected spent fuel elements from K-West Basin. The objective of these tests was to determine pyrophoric characteristics of samples cut from both damaged and undamaged regions of fhel elements. Furnace ignition tests were also petiormed on samples subjected to the conditioning process proposed by the Independent Technical Assessment and the Integrated Process Strategy to establish any significant effect on the SNF pyrophoric pefiormance parameters. Part of the analysis of the ignition data in this report was petiormed by FIuor Daniel Northwest. One of the safety issues being evaluated is the possibility of a fiel ignition during processing, handling, and transportation to the interim storage facility.
Date: August 10, 1999
Creator: Abrefah, John; Huang, Fan-Hsiung F.; Gerry, William M.; Gray, Walter J.; Marschman, Steven C. & Thornton, Thomas A.
Object Type: Report
System: The UNT Digital Library
Theory of high-{Tc} superconducting cuprates based on experimental evidence (open access)

Theory of high-{Tc} superconducting cuprates based on experimental evidence

A model of superconductivity in layered high-temperature superconducting cuprates is proposed, based on the extended saddle point singularities in the electron spectrum, weak screening of the Coulomb interaction and phonon-mediated interaction between electrons plus a small short-range repulsion of Hund's, or spin-fluctuation, origin. This permits to explain the large values of {Tc}, features of the isotope effect on oxygen and copper, the existence of two types of the order parameter, the peak in the inelastic neutron scattering, the positive curvature of the upper critical field, as function of temperature etc.
Date: December 10, 1999
Creator: Abrikosov, A. A.
Object Type: Article
System: The UNT Digital Library
Hybrid and conventional hydrogen engine vehicles that meet EZEV emissions (open access)

Hybrid and conventional hydrogen engine vehicles that meet EZEV emissions

In this paper, a time-dependent engine model is used for predicting hydrogen engine efficiency and emissions. The model uses basic thermodynamic equations for the compression and expansion processes, along with an empirical correlation for heat transfer, to predict engine indicated efficiency. A friction correlation and a supercharger/turbocharger model are then used to calculate brake thermal efficiency. The model is validated with many experimental points obtained in a recent evaluation of a hydrogen research engine. A The validated engine model is then used to calculate fuel economy and emissions for three hydrogen-fueled vehicles: a conventional, a parallel hybrid, and a series hybrid. All vehicles use liquid hydrogen as a fuel. The hybrid vehicles use a flywheel for energy storage. Comparable ultra capacitor or battery energy storage performance would give similar results. This paper analyzes the engine and flywheel sizing requirements for obtaining a desired level of performance. The results indicate that hydrogen lean-burn spark-ignited engines can provide a high fuel economy and Equivalent Zero Emission Vehicle (EZEV) levels in the three vehicle configurations being analyzed.
Date: December 10, 1996
Creator: Aceves, S. M. & Smith, J. R.
Object Type: Article
System: The UNT Digital Library
Global Climate Change: Selected Legal Questions About the Kyoto Protocol (open access)

Global Climate Change: Selected Legal Questions About the Kyoto Protocol

This report discusses the Kyoto Protocol and whether the United States is now legally bound by the Protocol, the legal implications of signing it, whether it could be implemented as an executive agreement without submission to the Senate, and whether the Protocol could be used as the legal basis for regulation of emissions even prior to ratification.
Date: April 10, 1998
Creator: Ackerman, David M.
Object Type: Report
System: The UNT Digital Library
”In God We Trust” on the Nation’s Coins and Currency and as the National Motto: History and Constitutionality (open access)

”In God We Trust” on the Nation’s Coins and Currency and as the National Motto: History and Constitutionality

This report discusses the history of the use of the phrase "In God We Trust" on the national currency, and the constitutional legality of the practice.
Date: July 10, 1996
Creator: Ackerman, David M.
Object Type: Report
System: The UNT Digital Library
Fiscal year 1999 waste information requirements document (open access)

Fiscal year 1999 waste information requirements document

The Waste Information Requirements Document (WIRD) has the following purposes: To describe the overall drivers that require characterization information and to document their source; To define how characterization is going to satisfy the drivers, close issues, and measure and report progress; and To describe deliverables and acceptance criteria for characterization. Characterization information is required to maintain regulatory compliance, perform operations and maintenance, resolve safety issues, and prepare for disposal of waste. Commitments addressing these requirements are derived from the Hanford Federal Facility Agreement and Consent Order, also known as the Tri-Party Agreement; the Recommendation 93-5 Implementation Plan (DOE-RL 1996a) to the Defense Nuclear Facilities Safety Board (DNFSB); and other requirement sources listed in Section 2.0. The Waste Information Requirements Document replaces the tank waste analysis plans and the tank characterization plan previously required by the Tri-Party Agreement, Milestone M-44-01 and M-44-02 series.
Date: August 10, 1998
Creator: Adams, M. R.
Object Type: Report
System: The UNT Digital Library
Molten salt oxidation for treating low-level mixed wastes (open access)

Molten salt oxidation for treating low-level mixed wastes

MS0 is a promising alternative to incineration for the treatment of a variety of organic wastes. Lawrence Livermore National Laboratory (LLNL) has prepared a facility (please see the photo attached) in which an integrated pilot-scale MS0 treatment system is being tested and demonstrated. The system consists of a MS0 vessel with a dedicated off-gas treatment system, a salt recycle system, feed preparation equipment, and a ceramic final waste forms immobilization system. The MSO/off-gas system has been operational since December 1997. The salt recycle system and the ceramic final forms immobilization became operational in May and August 1998, respectively. We have tested the MS0 facility with various organic feeds, including chlorinated solvents; tributyl phosphate/kerosene, PCB-contaminated waste oils & solvents, booties, plastic pellets, ion exchange resins, activated carbon, radioactive-spiked organics, and well-characterized low- level liquid mixed wastes. MS0 is a versatile technology for hazardous waste treatment and may be a solution to many waste disposal problems. In this paper we will present our operational experience with MS0 and also discuss its process capabilities as well as performance data with different feeds.
Date: December 10, 1998
Creator: Adamson, M G; Ford, T D; Foster, K G; Hipple, D L; Hopper, R W & Hsu, P C
Object Type: Article
System: The UNT Digital Library
The status of APS, BESSRC, and NEET. (open access)

The status of APS, BESSRC, and NEET.

We present a brief summary of the current status of the Advanced Photon Source (APS) at Argonne National Laboratory and of the facilities at two of the APS sectors operated by the Basic Energy Sciences Synchrotrons Radiation Center (BESSRC). This is followed by a report on recent measurements at BESSRC on the phenomenon of Nuclear Excitation by Electronic Transition (NEET).
Date: March 10, 1999
Creator: Ahmad, I.; Dunford, R. W.; Esbensen, H.; Gemmell, D. S.; Kanter, E. P.; Kraessig, B. et al.
Object Type: Article
System: The UNT Digital Library
Reciprocal-Space Analysis of Compositional Modulation in Short-Period Superlattices Using Position-Sensitive X-Ray Detection (open access)

Reciprocal-Space Analysis of Compositional Modulation in Short-Period Superlattices Using Position-Sensitive X-Ray Detection

Epitaxial growth of AlAs-InAs short-period superlattices on (001) InP can lead to heterostructures exhibiting strong, quasi-periodic, lateral modulation of the alloy composition; transverse satellites arise in reciprocal space as a signature of the compositional modulation. Using an x-ray diffractometer equipped with a position-sensitive x-ray detector, we demonstrate reciprocal-space mapping of these satellites as an efficient, nondestructive means for detecting and characterizing the occurrence of compositional modulation. Systematic variations in the compositional modulation due to the structural design and the growth conditions of the short-period superlattice are characterized by routine mapping of the lateral satellites. Spontaneous compositional modulation occurs along the growth front during molecular-beam epitaxy of (AlAs) (InAs)n short-period superlattices. The modulation is quasi-periodic and forms a lateral superlattice superimposed on the intended SPS structure. Corresponding transverse satellites arise about each reciprocal lattice point, and x-ray diffraction can be routinely used to map their local reciprocal-space structure. The integrated intensity, spacing, orientation, and shape of these satellites provide a reliable means for nondestructively detecting and characterizing the compositional modulation in short-period superlattices. The analytical efficiency afforded by the use of a PSD has enabled detailed study of systematic vacations in compositional modulation as a function of the average composition, the …
Date: November 10, 1998
Creator: Ahrenkiel, S. P.; Follstaedt, D. M.; Lee, S. R.; Millunchick, J. M.; Norman, A. G.; Reno, J. L. et al.
Object Type: Article
System: The UNT Digital Library
Quarterly Technical Progress Report - Investigation of Syngas Interaction in Alcohol Synthesis Catalysts (open access)

Quarterly Technical Progress Report - Investigation of Syngas Interaction in Alcohol Synthesis Catalysts

This report presents the work done on " Investigation of Syngas Interaction in Alcohol Synthesis Catalysts" during the last quarter. The major activity during this period is on FTIR absorption studies of Co/Cr catalysts using CO as a probe molecule. Transition metals cobalt and copper play significant roles in the conversion of syngas (CO + H2 ) to liquid fuels. With a view to examine the nature of interaction between CO and metal, the FTIR spectra of CO adsorbed on Co-Cr2 O3 composites were investigated. The results indicate that as cobalt loading increases, the intensity of the CO adsorption bands increase and several vibrational modes seem to be promoted. Heat treatment of the sample revealed two distinct processes of adsorption. Bands due to physisorption disappeared while bands due to chemisorption not only increased in intensity but persisted even after desorption. It seems that the physisorption process is more active when the catalyst is fresh and is hindered when carbidic/carbonyl formations occur on the metal surfaces.
Date: November 10, 1998
Creator: Akundi, Murty A.
Object Type: Report
System: The UNT Digital Library
An x-ray fluorescence study of lake sediments from ancient Turkey using synchrotron radiation. (open access)

An x-ray fluorescence study of lake sediments from ancient Turkey using synchrotron radiation.

Sediments from relic Lake Golbasi were analyzed by X-ray fluorescence with synchrotrons radiation to determine changes in element concentrations over time with selected elements serving as proxies for environmental change. Increases in Ca and Sr suggest soil formation during a dry period, from ca. 4500 BC to ca. 200 AD at which point K, Rb, Zr, Ti, and Y increase, indicating the return of a wet environment. Soil erosion, represented by Cr and Ni, increases ca. 7000 BC, probably as a consequence of environmental change, prior to suggested exploitation of natural resources by the newly urbanized society of the third millennium BC.
Date: March 10, 1999
Creator: Alatas, A.; Alp, E. E.; Friedman, E. S.; Jennings, G.; Johnson, C. E.; Lai, B. et al.
Object Type: Article
System: The UNT Digital Library
Characterization of the corrosion resistance of duplex stainless steels using local current density mapping techniques (open access)

Characterization of the corrosion resistance of duplex stainless steels using local current density mapping techniques

An in situ investigation of the dissolution behavior of duplex stainless steel has been carried out in acidic solutions containing 2.0 M HCl with 2.0 M H{sub 2}SO{sub 4} to determine differences in dissolution rates of the austenitic and ferritic phases. The current density distribution over the dissolving steel surface was measured using a vibrating electrode. The study demonstrated that this technique could quantify the differences in dissolution rates of the austenitic and ferritic phases under the conditions tested. The dissolution rates for the two phases peak at different potentials resulting in multiple current maxima. In addition, transients in dissolution behavior of the two phases at different potentials were observed using optical microscopy. Electron microscopy of the dissolved surface showed very high levels of aluminum and silicon enrichment on the austenitic phase.
Date: January 10, 1994
Creator: Aldykiewicz, A. & Isaacs, H. S.
Object Type: Report
System: The UNT Digital Library
A global overview of risk management of the DOE complex (open access)

A global overview of risk management of the DOE complex

No endeavor is risk-fire and as we realize the inherent risks in society, our only viable solution is to manage the risk. Application of an integrated risk management program of a large technological system like the DOE complex is a difficult, task; but it is the only rational means to optimize the risk-benefit equation. An effective risk management culture-within the DOE complex will in the long run, ensure a consistent response to mitigate identified risks. An effective risk management program provides responsible administrative planning and logical application of the best technical analyses. It requires the involvement of all personnel. Our objective in this paper is to point out broad perspectives that raise concerns about future DOE ask management issues and to suggest some possible remedies.
Date: October 10, 1993
Creator: Alesso, H. P. & Majumdar, K. C.
Object Type: Article
System: The UNT Digital Library
Behavior of nanocrystalline Xe precipitates in Al under 1 MeV electron irradiation. (open access)

Behavior of nanocrystalline Xe precipitates in Al under 1 MeV electron irradiation.

Crystalline nanoprecipitates of Xe have been produced by ion implantation into high purity Al at 300 K. With an off-zone axis TEM imaging technique, the nanocrystals may be clearly structure imaged against a nearly featureless background. Under the 1 MeV electron irradiation employed for the HREM observation, Xe nanocrystals exhibit a number of readily observed physical phenomena including migration within the matrix, changes in shape, faulting, melting, crystallization and coalescence. The various phenomena observed as changes in the Xe nanocrystals reflect changes of matrix cavity-surface structure. The Xe nanocrystal thus allows investigation indirectly into changes in interface morphology at the atomic level, resulting in this instance from electron irradiation damage. Such changes have heretofore been inaccessible to observation.
Date: March 10, 1999
Creator: Allen, C. W.; Birtcher, R. C.; Donnelly, S. E.; Furuya, K.; Mitsuishi, K. & Song, M.
Object Type: Article
System: The UNT Digital Library
Observation of an elementary cuboctahedron of Xe nanocrystal in an Al matrix. (open access)

Observation of an elementary cuboctahedron of Xe nanocrystal in an Al matrix.

When a noble gas element such as Xe is implanted in an fcc metal matrix such as Al at room temperature, a fine dispersion of precipitates forms. The precipitates are elementary fcc crystals up to diameters of several nanometers (for Xe in Al, 8-10 rim), above which they are non-crystalline. The precipitates exhibit a cube-on-cube orientation relation with the matrices and have lattice parameters which are much larger than those of the matrices (a{sub Xe} = 1.5a{sub Al}). Thus the interphase interfaces are incommensurate though the lattices are isotactic. The precipitates assume the shape of matrix cavities; for an Al matrix, at equilibrium this is a cuboctahedron, a {r_brace}111{l_brace} octahedron truncated at the corners on {l_brace}100{r_brace}. Fig. 1 is a sketch of a dispersion of such cuboctahedra, viewed approximately along a {l_angle}110{r_angle}. For this study specimens were prepared in the HVEM-Tandem Facility at Argonne National Laboratory by implanting 35 keV Xe to a dose of 4x10{sup 19} m{sup {minus}2} into well-annealed 5N Al discs which had been thinned by jet electropolishing. The range of the implant is approximately 25 nm. Specimens were examined at high resolution in the JEOL ARM-1000 high voltage electron microscope (HVEM) at the High Resolution Beam …
Date: March 10, 1999
Creator: Allen, C. W.; Birtcher, R. C.; Donnelly, S. E.; Furuya, K.; Ryan, E. A. & Song, M.
Object Type: Article
System: The UNT Digital Library
Neural Network-Based Resistance Spot Welding Control and Quality Prediction (open access)

Neural Network-Based Resistance Spot Welding Control and Quality Prediction

This paper describes the development and evaluation of neural network-based systems for industrial resistance spot welding process control and weld quality assessment. The developed systems utilize recurrent neural networks for process control and both recurrent networks and static networks for quality prediction. The first section describes a system capable of both welding process control and real-time weld quality assessment, The second describes the development and evaluation of a static neural network-based weld quality assessment system that relied on experimental design to limit the influence of environmental variability. Relevant data analysis methods are also discussed. The weld classifier resulting from the analysis successfldly balances predictive power and simplicity of interpretation. The results presented for both systems demonstrate clearly that neural networks can be employed to address two significant problems common to the resistance spot welding industry, control of the process itself, and non-destructive determination of resulting weld quality.
Date: July 10, 1999
Creator: Allen, J.D., Jr.; Ivezic, N.D. & Zacharia, T.
Object Type: Article
System: The UNT Digital Library