Approximation of attractors and applications (open access)

Approximation of attractors and applications

The aim of the research project is to explore what can be learned about turbulence from the theoretical and computational viewpoints, using the dynamical systems approach to turbulence.
Date: October 23, 1992
Creator: Temam, R.
Object Type: Report
System: The UNT Digital Library
Approximation of attractors and applications final report, May 1, 1992--April 30, 1995 (open access)

Approximation of attractors and applications final report, May 1, 1992--April 30, 1995

A theoretical and computational study of turbulence, using the dynamical systems approach, is reported. Topics explored included the Navier-Stokes equations and turbulence, approximation of attractors, and climatology problems.
Date: October 23, 1995
Creator: Temam, R.
Object Type: Report
System: The UNT Digital Library
Approximation of attractors and applications. Progress report, May 1, 1992--October 31, 1992 (open access)

Approximation of attractors and applications. Progress report, May 1, 1992--October 31, 1992

The aim of the research project is to explore what can be learned about turbulence from the theoretical and computational viewpoints, using the dynamical systems approach to turbulence.
Date: October 23, 1992
Creator: Temam, Roger
Object Type: Report
System: The UNT Digital Library
Audit of the deactivation, decontamination, and disposal of surplus facilities at the Savannah River Site (open access)

Audit of the deactivation, decontamination, and disposal of surplus facilities at the Savannah River Site

Westinghouse Savannah River Company (Westinghouse) is responsible for managing the Department of Energy`s (Department) surplus facilities at the Savannah River Site (Site). In Fiscal Year (FY) 1996, the Site had 162 surplus facilities and anticipated that 118 more would become surplus within the next 5 years. The objective of this audit was to determine whether the Savannah River Operations Office (Operations Office) and Westinghouse had economically and promptly deactivated, decontaminated, and disposed of surplus facilities at the Site. Departmental regulations require that surplus facilities be deactivated, decontaminated, and disposed of economically and promptly. However, Westinghouse only disposed of one facility and did not completely deactivate or decontaminate any of the 162 facilities identified as surplus at the Site in FY 1996. This occurred because the Operations Office did not compile a Site-wide list, establish priorities, or provide sufficient funding for the deactivation, decontamination, and disposal of surplus facilities. As a result, the Department incurred unnecessary costs for the surveillance and maintenance of surplus facilities. For example, the Department could have avoided annual costs of about $1.3 million in surveillance and maintenance costs by spending $1.2 million to perform a deactivation project on the P-Reactor process-water storage tanks. The Operations Office …
Date: October 23, 1997
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Calibration of the MACHO photometry database (open access)

Calibration of the MACHO photometry database

The MACHO Project is a microlensing survey that monitors the brightnesses of -60 million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud, and Galactic bulge. The database presently contains more photometric measurements than previously recorded in the history of astronomy. We describe the calibration of the MACHO two-color photometry and transformation to the standard Kron-Cousins V and R system. This allows for proper comparison with all other observations on the Kron-Cousins standard system. The highest precision calibrations are for -9 million stars in the LMC bar. For these stars, independent photometric measurements in field-overlap regions indicate standard deviations {sigma}{sub V} = {sigma}{sub R} = 0.020 mag. Calibrated MACHO photometry data are compared with published photometric sequences and with new Hubble Space Telescope observations. We additionally describe the first application of these calibrated data: the construction of the �efficiency� color-magnitude diagram which will be used to calculate our experimental sensitivity for detecting microlensing in the LMC.
Date: October 23, 1998
Creator: Alcock, A.
Object Type: Article
System: The UNT Digital Library
Completion of Hanford Tanks Initiative characterization milestone T04-98-523 (open access)

Completion of Hanford Tanks Initiative characterization milestone T04-98-523

The HTI subsurface characterization task will use the Hanford Cone Penetrometer platform (CPP) to deploy soil sensor and sampling probes into the vadose zone/soils around AX-104 during FY-99. This document provides copies of the first data collected from the HTI sensor probes during vendor field developmental tests performed at a Cold test site in the Hanford 200 East area. Conduct of the initial test also established completion of a major contractor milestone of the HTI Characterization task (MS T04-98-523: Complete preparation of the HTICP probes and transfer to Hanford/HTI. Conduct an initial MSP push using the CPP).
Date: October 23, 1998
Creator: IWATATE, D.F.
Object Type: Report
System: The UNT Digital Library
Decarburization of uranium via electron beam processing (open access)

Decarburization of uranium via electron beam processing

For many commercial and military applications, the successive Vacuum Induction Melting of uranium metal in graphite crucibles results in a product which is out of specification in carbon. The current recovery method involves dissolution of the metal in acid and chemical purification. This is both expensive and generates mixed waste. A study was undertaken at Lawrence Livermore National Laboratory to investigate the feasibility of reducing the carbon content of uranium metal using electron beam techniques. Results will be presented on the rate and extent of carbon removal as a function of various operating parameters.
Date: October 23, 1998
Creator: McKoon, R H
Object Type: Article
System: The UNT Digital Library
[The design and construction of the proposed L* detector for the Superconducting Super Collider] (open access)

[The design and construction of the proposed L* detector for the Superconducting Super Collider]

Dr. William M. Bugg and a group from ORNL had very productive meetings with Professor Sam Ting and other members of the L3 collaboration. The L3 detector system, subsystems, and the associated support facilities were examined in some detail. Discussions were held with scientists involved in planning for the L* detector systems and members of the L3 staff interested in positions at ORNL/UTK. The trip was very successful. A collaborative arrangement was established for UTK and ORNL to become involved in the future design and construction of the L* detector. These include hosting the main meeting of the L* collaboration at ORNL to complete the Expression-of-Interest (EOI) proposal. Several prospective candidates were interviewed and collaborative interactions were started on some detector subsystems for L*.
Date: October 23, 1990
Creator: Bugg, William M.
Object Type: Report
System: The UNT Digital Library
Detailed Comparison Between Parton Cascade and Hadronic Cascade at SPS and RHIC (open access)

Detailed Comparison Between Parton Cascade and Hadronic Cascade at SPS and RHIC

The authors study the importance of the partonic phase produced in relativistic heavy ion collision by comparing the parton cascade model and the hadronic cascade model. Hadron yield, baryon stopping and transverse momentum distribution are calculated with JAM and discussions are given comparing with VNI. Both of these models give good description of experimental data. They also discuss the strangeness production mechanism and the directed transverse flow.
Date: October 23, 1998
Creator: Nara, Y.
Object Type: Article
System: The UNT Digital Library
Development and testing of a commercial scale coal-fired combustion system, Phase 3. Quarterly technical progress report No. 8, July 1, 1992--September 30, 1992 (open access)

Development and testing of a commercial scale coal-fired combustion system, Phase 3. Quarterly technical progress report No. 8, July 1, 1992--September 30, 1992

This report summarizes the results of work performed in the development and proof-of-concept (POC) testing of a coal-fired space heating system for the commercial market sector. The objective of this program is to design, build and test a coal based heating system for this sector and determine the economic viability and market potential for the system. Coal water slurry (CWS) fuel has been chosen as the fuel form for this development effort. CWS eliminates the need to use dry pulverized coal with its attendant handling, metering and dusting problems as well as its explosive potential. Equally important in selecting a fuel form is the impact on emission levels and pollution control equipment requirements. CWS is amenable to coal washing since coal cleaning technologies are generally water-based processes requiring the fine grinding of the coal. In the first stage. an overall system heat balance was prepared, system components were designed and manufactured or purchased, the system was fully assembled and preliminary testing performed to validate component performance and identify key operating variables. In the second stage the system was operated for prolonged periods to simulate a commercial application, and combustion and thermal efficiencies; tendencies to slag, foul, erode and corrode; and …
Date: October 23, 1992
Creator: Litka, A. & Breault, R.
Object Type: Report
System: The UNT Digital Library
Development of an advanced, continuous mild gasification process for the production of coproducts (open access)

Development of an advanced, continuous mild gasification process for the production of coproducts

Research continued on the production of coproducts from continuous mild gasification. During the third quarter of 1990, work focused on start-up and operation of the 50 pound/hour char-to-carbon (CTC) process research unit (PRU). Start-up procedures have been finalized for the methane production reactor, and the design temperature has been achieved. Flows and pressures for the overall process have been balanced and optimized. We have achieved temperatures above 1500{degree}F in the carbon formation reactor. Upgrading experiments on mild gasification pitch have also continued on a pitch produced in run MG-122. Results of heat treating and catalytic treating tests are reported.
Date: October 23, 1990
Creator: Jha, M. C.; McCormick, R. L.; Hogsett, R. F. & Rowe, R. M.
Object Type: Report
System: The UNT Digital Library
Dosimetry quality assurance in Martin Marietta Energy Systems' centralized external dosimetry system (open access)

Dosimetry quality assurance in Martin Marietta Energy Systems' centralized external dosimetry system

External dosimetry needs at the four Martin Marietta Energy Systems facilities are served by Energy Systems Centralized External Dosimetry System (CEDS). The CEDS is a four plant program with four dosimeter distribution centers and two dosimeter processing centers. Each plant has its own distribution center, while processing centers are located at ORNL and the Y-12 Plant. The program has been granted accreditation by the Department of Energy Laboratory Accreditation Program (DOELAP). The CEDS is a TLD based system which is responsible for whole-body beta-gamma, neutron, and extremity monitoring. Beta-gamma monitoring is performed using the Harshaw/Solon Technologies model 8805 dosimeter. Effective October 1, 1992 the standard silver mylar has been replaced with an Avery mylar foil blackened on the underside with ink. This was done in an effort to reduce the number of light induced suspect readings. At this time we have little operational experience with the new blackened mylars-The CEDS neutron dosimeter is the Harshaw model 8806B. This card/holder configuration contains two TLD-600/TLD-700 chip pairs; one pair is located beneath a cadmium filter and one pair is located beneath a plastic filter. In routine personnel monitoring the CEDS neutron dosimeter is always paired with a CEDS beta-gamma dosimeter.The CEDS extremity …
Date: October 23, 1992
Creator: Souleyrette, M.L.
Object Type: Article
System: The UNT Digital Library
Electrically Switched Cesium Ion Exchange (open access)

Electrically Switched Cesium Ion Exchange

This report discusses the results of work to develop Electrically Switched Ion Exchange (ESIX) for separations of ions from waste streams relevant to DOE site clean-up. ESIX combines ion exchange and electrochemistry to provide a selective, reversible method for radionuclide separation that lowers costs and minimizes secondary waste generation typically associated with conventional ion exchange. In the ESIX process, an electroactive ion exchange film is deposited onto. a high surface area electrode, and ion uptake and elution are controlled directly by modulating the potential of the film. As a result, the production of secondary waste is minimized, since the large volumes of solution associated with elution, wash, and regeneration cycles typical of standard ion exchange are not needed for the ESIX process. The document is presented in two parts: Part I, the Summary Report, discusses the objectives of the project, describes the ESIX concept and the approach taken, and summarizes the major results; Part II, the Technology Description, provides a technical description of the experimental procedures and in-depth discussions on modeling, case studies, and cost comparisons between ESIX and currently used technologies.
Date: October 23, 1998
Creator: Sukamto, Johanes P. H.; Lilga, Michael A. & Orth, Rick J.
Object Type: Report
System: The UNT Digital Library
Evaluation of Effectiveness of the Turco Low Profile Turbulator Reg Sign (open access)

Evaluation of Effectiveness of the Turco Low Profile Turbulator Reg Sign

This document discusses a turbulator which utilizes a heated chemical bath to reduce smearable contamination from small parts and tools. It is comprised of two agitators programmed to automatically alternate the flow of the cleaning solution within the tank in four separate and distinct high velocity flow patterns allowing access to the entire surface area of the part or tool being decontaminated. The turbulator is being evaluated to determine if agitation increases the effectiveness of waste minimization. Testing of the turbulator consisted of evaluation of the Sludgetrap Containment, Tool Cleaning Demonstration, and Coupon Testing. Results so far are that the sludgetrap is effective in containing particles the size of sand, agitation increases the effectiveness of the turbulator, abrasives can replace detergents for waste minimization, and Inconel 625 is more difficult to clean than Type 3041 Stainless Steel.
Date: October 23, 1990
Creator: Grittmann, S.; McGlynn, J. F.; Long, J. R. & Rankin, W. N.
Object Type: Report
System: The UNT Digital Library
Evaluation of effectiveness of the Turco low profile turbulator{reg_sign} (open access)

Evaluation of effectiveness of the Turco low profile turbulator{reg_sign}

This document discusses a turbulator which utilizes a heated chemical bath to reduce smearable contamination from small parts and tools. It is comprised of two agitators programmed to automatically alternate the flow of the cleaning solution within the tank in four separate and distinct high velocity flow patterns allowing access to the entire surface area of the part or tool being decontaminated. The turbulator is being evaluated to determine if agitation increases the effectiveness of waste minimization. Testing of the turbulator consisted of evaluation of the Sludgetrap Containment, Tool Cleaning Demonstration, and Coupon Testing. Results so far are that the sludgetrap is effective in containing particles the size of sand, agitation increases the effectiveness of the turbulator, abrasives can replace detergents for waste minimization, and Inconel 625 is more difficult to clean than Type 3041 Stainless Steel.
Date: October 23, 1990
Creator: Grittmann, S.; McGlynn, J. F.; Long, J. R. & Rankin, W. N.
Object Type: Report
System: The UNT Digital Library
Examination of glass-silicon and glass-glass bonding techniques for microfluidic systems (open access)

Examination of glass-silicon and glass-glass bonding techniques for microfluidic systems

We report here on the results of experiments concerning particular bonding processes potentially useful for ultimate miniaturization of microfluidic systems. Direct anodic bonding of continuous thin pyrex glass of 250 {mu}m thickness to silicon substrates gives multiple, large voids in the glass. Etchback of thick glass of 1200 {mu}m thickness bonded to silicon substrates gives thin continuous glass layers of 189 {mu}m thickness without voids over areas of 5 cm {times} 12 cm. Glass was also successfully bonded to glass by thermal bonding at 800{degrees}C over a 5 cm {times} 7 cm area. Anticipated applications include microfabricated DNA sequencing, flow injection analysis, and liquid and gas chromatography microinstruments.
Date: October 23, 1995
Creator: Raley, N. F.; Davidson, J. C. & Balch, J. W.
Object Type: Article
System: The UNT Digital Library
Flame quality monitor system for fixed firing rate oil burners (open access)

Flame quality monitor system for fixed firing rate oil burners

A method and apparatus for determining and indicating the flame quality, or efficiency of the air-fuel ratio, in a fixed firing rate heating unit, such as an oil burning furnace, is provided. When the flame brightness falls outside a preset range, the flame quality, or excess air, has changed to the point that the unit should be serviced. The flame quality indicator output is in the form of lights mounted on the front of the unit. A green light indicates that the flame is about in the same condition as when the burner was last serviced. A red light indicates a flame which is either too rich or too lean, and that servicing of the burner is required. At the end of each firing cycle, the flame quality indicator goes into a hold mode which is in effect during the period that the burner remains off. A yellow or amber light indicates that the burner is in the hold mode. In this mode, the flame quality lights indicate the flame condition immediately before the burner turned off. Thus the unit can be viewed when it is off, and the flame condition at the end of the previous firing cycle can …
Date: October 23, 1990
Creator: Butcher, T. A. & Cerniglia, P.
Object Type: Patent
System: The UNT Digital Library
Fuel powder production from ductile uranium alloys. (open access)

Fuel powder production from ductile uranium alloys.

Metallic uranium alloys are candidate materials for use as the fuel phase in very-high-density LEU dispersion fuels. These ductile alloys cannot be converted to powder form by the processes routinely used for oxides or intermetallics. Three methods of powder production from uranium alloys have been investigated within the US-RERTR program. These processes are grinding, cryogenic milling, and hydride-dehydride. In addition, a gas atomization process was investigated using gold as a surrogate for uranium. Grinding was found to be inefficient and introduced impurities into the fuel. Cryogenic milling of machine chips in a steel vial was found to have similar shortcomings. The hydride-dehydride process has historically been used to produce very fine powder that may not be suitable for fuel fabrication. Uranium is made to form its hydride by heating in a hydrogen atmosphere. Subsequent heating under vacuum drives off hydrogen gas and returns the hydride to a metallic state. The volume change on hydride formation results in a fine powder upon dehydriding. The effects of alloying elements, partial hydriding, and subsequent milling treatments on particle size distribution are being explored. Inert gas atomization is used on an industrial scale to produce metal powder. Current designs are not suitable for use …
Date: October 23, 1998
Creator: Clark, C. R.
Object Type: Article
System: The UNT Digital Library
Hanford Quarter Seismic Report - 98C Seismicity On and Near the Hanford Site, Pasco Basin, Washington: April 1, 1998 Through June 30, 1998 (open access)

Hanford Quarter Seismic Report - 98C Seismicity On and Near the Hanford Site, Pasco Basin, Washington: April 1, 1998 Through June 30, 1998

Hanford Seismic Monitoring provides an uninterrupted collection of high-quality raw and processed seismic data from the Hanford Seismic Network (HSN) for the U.S. Department of Energy and its contractors. The staff also locates aud identifies sources of seismic activity and monitors changes in the hi~orical pattern of seismic activity at the Hanford Site. The data are. compiled archived, and published for use by the Hanford Site for waste management Natural Phenomena Hazards assessments, and engineering design and construction. In addition, the seismic monitoring organization works with the Hanford Site Emergency Services Organization to provide assistance in the event of zin earthquake on the Hanford Site. The HSN and Ihe Eastern Washington Regional Network (EN/RN) consist-of 42 individual sensor sites and 15 radio relay sites maintained by the Hanford Seismic Monitoring staff. The operational rate for the third quarter of FY 1998 for stations in the HSN was 99.99%. The operational rate for the third quarter of FY 1998 for stations of the EWRN was 99.95%. For the third quarter of FY 1998, the acquisition computer triggered 133 times. Of these triggers 11 were local earthquakes: 5 (45Yo) in the Columbia River Basalt Group, 2(1 8%) in the pre-basalt sediments, and …
Date: October 23, 1998
Creator: DC Hartshorn, SP Reidel, AC Rohay
Object Type: Report
System: The UNT Digital Library
Heat Capacity Measurements in Pulsed Magnetic Fields (open access)

Heat Capacity Measurements in Pulsed Magnetic Fields

The new NHMFL 60T quasi-continuous magnet produces a flat-top field for a period of 100 ms at 60 Tesla, and for longer time at lower fields, e.g. 0.5 s at 45 Tesla. We have developed for the first time the capability to measure heat capacity at very high magnetic fields in the NHMFL 60T quasi-continuous magnet at LANL, using a probe built out of various plastic materials. The field plateau allows us to utilize a heat-pulse method to obtain heat capacity data. Proof-of-principle heat capacity experiments were performed on a variety of correlated electron systems. Both magnet performance characteristics and physical properties of various materials studied hold out a promise of wide application of this new tool.
Date: October 23, 1998
Creator: Jaime, M.; Movshovich, R.; Sarrao, J.L.; Kim, J.; Stewart, G.; Beyermann, W.P. et al.
Object Type: Article
System: The UNT Digital Library
High accuracy capture of curved shock fronts using the method of space-time conservation element and solution elemen (open access)

High accuracy capture of curved shock fronts using the method of space-time conservation element and solution elemen

Split numerical methods have been commonly used in computational physics for many years due to their speed, simplicity, and the accessibility of shock capturing methods in one-dimension. For a variety of reasons, it has been challenging to determine just how accurate operator split methods are, especially in the presence of curved wave features. One of these difficulties has been the lack of multidimensional shock capturing methods. Another is the difficulty of mathematical analysis of dis-continuous flow phenomena. Also, computational studies have been limited due to a lack of multidimensional model problems with analytic solutions that probe the nonlinear features of the flow equations. However, a new genuinely unsplit numerical method has been invented. With the advent of the Space-Time Conservation Element/Solution Element (CE/SE) method, it has become possible to attain high accuracy in multidimensional flows, even in the presence of curved shocks. Examples presented here provide some new evidence of the errors committed in the use of operator split techniques, even those employing �unsplit� corrections. In these problems, the CE/SE method is able to maintain the original cylindrical symmetry of the problem and track the main features of the flow, while the operator split methods fail to maintain symmetry and …
Date: October 23, 1998
Creator: Cook, Jr., G
Object Type: Article
System: The UNT Digital Library
Improvement of Azimuthal Homogeneity in Permanent-Magnet Bearing Rotors (open access)

Improvement of Azimuthal Homogeneity in Permanent-Magnet Bearing Rotors

Permanent magnets that are levitated and rotating over a bulk high-temperature superconductor (HTS) form the basis of many superconducting bearing designs. Experiments have shown that the rotational-loss coefficient of friction'' for thrust bearings of this type can be as low as 8 [times] 10[sup [minus]6]. While the loss mechanisms of such bearings are not well understood, the azimuthal homogeneity of the rotating permanent magnet is believed to play an important role in determining the loss. One possible loss mechanism is magnetic hysteresis in the HTS, where the energy loss E per cycle is derived from the critical state model and given by E = K ([Delta]B[sup 3]/J[sub c]) where K is a geometric coefficient, [Delta]B is the variation in magnetic field at the surface of the HTS experienced during a rotation of the levitated magnet, and J[sub c] is the critical current density of the HTS. It is clear that a small decrease in [Delta]B (i.e., decreasing the azimuthal inhomogeneity of the rotating magnetic field) could have profound effects on decreasing E and the rotational coefficient of friction. The role of [Delta]B is also expected to be significant in reducing losses from eddy currents and other mechanisms. Low rotational losses …
Date: October 23, 1992
Creator: Hull, J. R.; Rossing, T. D.; Mulcahy, T. M. & Uherka, K. L.
Object Type: Article
System: The UNT Digital Library
Improvement of Azimuthal Homogeneity in Permanent-Magnet Bearing Rotors (open access)

Improvement of Azimuthal Homogeneity in Permanent-Magnet Bearing Rotors

Permanent magnets that are levitated and rotating over a bulk high-temperature superconductor (HTS) form the basis of many superconducting bearing designs. Experiments have shown that the rotational-loss``coefficient of friction`` for thrust bearings of this type can be as low as 8 {times} 10{sup {minus}6}. While the loss mechanisms of such bearings are not well understood, the azimuthal homogeneity of the rotating permanent magnet is believed to play an important role in determining the loss. One possible loss mechanism is magnetic hysteresis in the HTS, where the energy loss E per cycle is derived from the critical state model and given by E = K ({Delta}B{sup 3}/J{sub c}) where K is a geometric coefficient, {Delta}B is the variation in magnetic field at the surface of the HTS experienced during a rotation of the levitated magnet, and J{sub c} is the critical current density of the HTS. It is clear that a small decrease in {Delta}B (i.e., decreasing the azimuthal inhomogeneity of the rotating magnetic field) could have profound effects on decreasing E and the rotational coefficient of friction. The role of {Delta}B is also expected to be significant in reducing losses from eddy currents and other mechanisms. Low rotational losses in …
Date: October 23, 1992
Creator: Hull, J. R.; Rossing, T. D.; Mulcahy, T. M. & Uherka, K. L.
Object Type: Article
System: The UNT Digital Library
In-situ transmission electron microscopy study of ion-irradiated copper : comparison of the temperature dependence of cascade collapse in FCC- and BCC- metals. (open access)

In-situ transmission electron microscopy study of ion-irradiated copper : comparison of the temperature dependence of cascade collapse in FCC- and BCC- metals.

The kinetics which drive cascade formation and subsequent collapse into point-defect clusters is investigated by analyzing the microstructure produced in situ by low fluence 100 keV Kr ion irradiations of fcc-Cu over a wide temperature range (18-873 K). The yield of collapsed point-defect clusters is demonstrated unequivocally to be temperature dependent, remaining approximately constant up to lattice temperatures of 573 K and then abruptly decreasing with increasing temperature. This drop in yield is not caused by defect loss during or following ion irradiation. This temperature dependence can be explained by a thermal spike effect. These in-situ yield measurements are compared to previous ex-situ yield measurements in fcc-Ni and bcc-Mo.
Date: October 23, 1998
Creator: Daulton, T. L.
Object Type: Article
System: The UNT Digital Library