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Evaluation of cracking in the 241-AZ tank farm ventilation line at the Hanford Site
In the period from April to October of 1988, a series of welding operations on the outside of the AZ Tank Farm ventilation line piping at the Hanford Site produced unexpected and repeated cracking of the austenitic stainless steel base metal and of a seam weld in the pipe. The ventilation line is fabricated from type 304L stainless steel pipe of 24 inch diameter and 0.25 inch wall thickness. The pipe was wrapped in polyethylene bubble wrap and buried approximately 12 feet below grade. Except for the time period between 1980 and 1987, impressed current cathodic protection has been applied to the pipe since its installation in 1974. The paper describes the history of the cracking of the pipe, the probable cracking mechanisms, and the recommended future action for repair/replacement of the pipe.
Date:
October 20, 1999
Creator:
ANANTATMULA, R.P.
Object Type:
Article
System:
The UNT Digital Library
Bipolaron Hopping Conduction in Boron Carbides
The electrical conductivities of boron carbides, B{sub 12+x}C{sub 3{minus}x} with 0.1 < x < 1.7, between 300 and 1200K suggest the hopping of a nearly temperature-independent density of small (bi)polarons. The activation energies of the nobilities are low, {approx} 0.16 eV, and are nearly independent of the composition. At lower temperatures, conductivities have non-Arrhenius temperature dependencies and strong sensitivity to carbon concentration. Percolative aspects of low-temperature hopping are evident in this sensitivity to composition. Boron carbides' Seebeck coefficients are anomalous in that (1) they are much larger than expected from boron carbides' large carrier densities and (2) they depend only weakly on the carrier density. Carrier-induced softening of local vibrations gives contributions to the Seebeck coefficient that mirror the magnitudes and temperature dependencies found in boron carbides.
Date:
September 20, 1999
Creator:
ASELAGE, TERRENCE L.; EMIN, D. & MCCREADY, STEVEN S.
Object Type:
Article
System:
The UNT Digital Library
New Measurement of A{sub b} at the Z{sup 0} Resonance Using a Vertex Charge Technique
We present a new preliminary measurement of the parity-violation parameter A{sub b} using a self-calibrating vertex-charge technique. In the SLD experiment we observe hadronic decays of Z{sup 0} bosons produced in collisions between longitudinally polarized electrons and unpolarized positrons at the SLAC Linear Collider. A sample of b{bar b} events is selected using the topologically reconstructed mass of B hadrons. From our 1996-1998 data sample of approximately 400,000 hadronic Z{sup 0} decays, we obtain A{sub b} = 0.897 {+-} 0.027(stat){sub -0.034}{sup +0.036}(syst).
Date:
July 20, 1999
Creator:
Abe, K
Object Type:
Report
System:
The UNT Digital Library
U.S./Russian cooperative efforts to enhance nuclear MPC&A at VNIITF, (Chelyabinsk-70)
The work described here is part of an effort called the Nuclear Materials Protection, Control, and Accounting (MPC&A) Program, a cooperative program between the US Department of Eenrgy (DOE) and Russia's Ministry of Atomic Energy (MinAtom). The objective of the program is to reduce the risk of nuclear proliferation by strengthening MPC&A systems at Russian nuclear Facilities. This paper describes that portion of the MPC&A program that is directed specifically to the needs of the All Russian Scientific Research Institute of Technical Physics (VNIITF), also called Chelyabinsk-70. A major MPC&A milestone was met at VNIITF when the MPC&A improvements were commissioned at the Pulse Research Reactor Facility in May of this year.
Date:
April 20, 1999
Creator:
Abramson, B.; Apt, K.; Blasy, J.; Bukin, D.; Churikov, Y.; Curtis, D. et al.
Object Type:
Article
System:
The UNT Digital Library
An advanced control system for fine coal flotation
None
Date:
December 20, 1999
Creator:
Adel, G. T. & Luttrell, G. H.
Object Type:
Report
System:
The UNT Digital Library
A Semiconductor Microlaser for Intracavity Flow Cytometry
Semiconductor microlasers are attractive components for micro-analysis systems because of their ability to emit coherent intense light from a small aperture. By using a surface-emitting semiconductor geometry, we were able to incorporate fluid flow inside a laser microcavity for the first time. This confers significant advantages for high throughput screening of cells, particulates and fluid analytes in a sensitive microdevice. In this paper we discuss the intracavity microfluidics and present preliminary results with flowing blood and brain cells.
Date:
January 20, 1999
Creator:
Akhil, O.; Copeland, G. C.; Dunne, J. L.; Gourley, P. L.; Hendricks, J. K. & McDonald, A. E.
Object Type:
Article
System:
The UNT Digital Library
Inclusive Jet Production at CDF
The inclusive jet cross section was measured by CDF at center of mass energies of 1800 and 630 GeV. At {radical}s =1800 GeV, the inclusive jet cross section is compared with NLO QCD predictions (with different sets of parton distribution functions) and with measurement by D0 Collaboration. Strong coupling constant is extracted (as a consistency check) from 1800 GeV inclusive jet data. The ratio of scaled inclusive jet cross sections measured at two values of {radical}s is compared with NLO QCD predictions. Comparison with D0 result is also shown.
Date:
July 20, 1999
Creator:
Akopian, A.
Object Type:
Article
System:
The UNT Digital Library
Progress Report for Annex II--Assessment of Solar Radiation Resources in Saudi Arabia 1993-1997
In 1987, the United States Department of Energy (DOE) and the King Abdulaziz City for Science and Technology (KACST) signed a five-year Agreement for Cooperation in the Field of Renewable Energy Research and Development (R and D), which has been extended to 2000. Tasks include: (1) upgrade solar radiation measurements in Saudi Arabia; (2) assemble a database of concurrent solar radiation, satellite (METEOSAT), and meteorological data; (3) adapt NREL models and other software for Saudi Arabia; (4) develop procedures, algorithms, and software to estimate solar irradiance; and (5) prepare a grid of solar radiation data for preparing maps and atlases and estimating solar radiation resources and solar energy system performances at locations in Saudi Arabia.
Date:
August 20, 1999
Creator:
Al-Amoudi, Anmed; Alawaji, Saleh H.; Cornwall, Chris; Mahfoodh, Mohammed bin; Marion, Bill; Maxwell, Eugene L. et al.
Object Type:
Report
System:
The UNT Digital Library
Investigation of Oxidative Degradation in Polymers Using (17)O NMR Spectroscopy
The thermal oxidation of pentacontane (C{sub 50}H{sub 102}), and of the homopolymer polyisoprene, has been investigated using {sup 17}O NMR spectroscopy. By performing the oxidation using {sup 17}O labeled O{sub 2} gas, it is possible to easily identify degradation products, even at relatively low concentrations. It is demonstrated that details of the degradation mechanism can be obtained from analysis of the {sup 17}O NMR spectra as a function of total oxidation. Pentacontane reveals the widest variety of reaction products, and exhibits changes in the relative product distributions with increasing O{sub 2} consumption. At low levels of oxygen incorporation, peroxides are the major oxidation product, while at later stages of degradation these species are replaced by increasing concentrations of ketones, alcohols, carboxylic acids and esters. Analyzing the product distribution can help in identification of the different free-radical decomposition pathways of hydroperoxides, including recombination, proton abstraction and chain scission, as well as secondary reactions. The {sup 17}O NMR spectra of thermally oxidized polyisoprene reveal fewer degradation functionalities, but exhibit an increased complexity in the type of observed degradation species due to structural features such as unsaturation and methyl branching. Alcohols and ethers formed from hydrogen abstraction and free radical termination.
Date:
July 20, 1999
Creator:
Alam, Todd M.; Celina, Mathew; Assink, Roger A.; Clough, Roger L.; Gillen, Kenneth T. & R., Wheeler David
Object Type:
Article
System:
The UNT Digital Library
The Oklahoma Daily (Norman, Okla.), Vol. 83, No. 87, Ed. 1 Wednesday, January 20, 1999
Student newspaper of the University of Oklahoma in Norman, Oklahoma that includes national, local, and campus news along with advertising.
Date:
January 20, 1999
Creator:
Allam, Heather
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
The Oklahoma Daily (Norman, Okla.), Vol. 83, No. 144, Ed. 1 Tuesday, April 20, 1999
Student newspaper of the University of Oklahoma in Norman, Oklahoma that includes national, local, and campus news along with advertising.
Date:
April 20, 1999
Creator:
Allam, Heather
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
Band Structure of InGaAsN Alloys and Effects of Presure
InGaAsN is a new semiconductor alloy system with the remarkable property that the inclusion of only 2% nitrogen reduces the bandgap by more than 30%. In order to help understand the physical origin of this extreme deviation from the typically observed nearly linear dependence of alloy properties on concentration, we have investigated the pressure dependence of state energies using both experimental and theoretical methods. the excited We report measurements of the low temperature photoluminescence of the material for pressures between ambient and 110 kbar. We also describe a simple, density- functional-theory-based approach to calculating the pressure dependence of low lying excitation energies for low concentration alloys. The theoretically predicted pressure dependence of the bandgap is in excellent agreement with the experimental data. Based on the results of our calculations, we suggest an explanation for the strongly non-linear pressure dependence of the bandgap that, surprisingly, does not involve a nitrogen impurity state.
Date:
January 20, 1999
Creator:
Allerman, A. A.; Jones, E. D.; Kurtz, S. R.; Modine, N. A.; Tozer, S. T.; Wei, X. et al.
Object Type:
Article
System:
The UNT Digital Library
Improved performance of the laser guide star adaptive optics system at Lick Observatory
Results of experiments with the laser guide star adaptive optics system on the 3-meter Shane telescope at Lick Observatory have demonstrated a factor of 4 performance improvement over previous results. Stellar images recorded at a wavelength of 2 {micro}m were corrected to over 40% of the theoretical diffraction-limited peak intensity. For the previous two years, this sodium-layer laser guide star system has corrected stellar images at this wavelength to {approx}10% of the theoretical peak intensity limit. After a campaign to improve the beam quality of the laser system, and to improve calibration accuracy and stability of the adaptive optics system using new techniques for phase retrieval and phase-shifting diffraction interferometry, the system performance has been substantially increased. The next step will be to use the Lick system for astronomical science observations, and to demonstrate this level of performance with the new system being installed on the 10-meter Keck II telescope.
Date:
July 20, 1999
Creator:
An, J. R.; Avicola, K.; Bauman, B. J.; Brase, J. M.; Campbell, E. W.; Carrano, C. et al.
Object Type:
Article
System:
The UNT Digital Library
A Modular Telerobot Control System for Accident Response
The Accident Response Mobile Manipulator System (ARMMS) is a teleoperated emergency response vehicle that deploys two hydraulic manipulators, five cameras, and an array of sensors to the scene of an incident. It is operated from a remote base station that can be situated up to four kilometers away from the site. Recently, a modular telerobot control architecture called SMART (Sandia's Modular Architecture for Robotic and Teleoperation) was applied to ARMMS to improve the precision, safety, and operability of the manipulators on board. Using SMART, a prototype manipulator control system was developed in a couple of days, and an integrated working system was demonstrated within a couple of months. New capabilities such as camera teleoperation, autonomous tool changeout and dual manipulator control have been incorporated. The final system incorporates twenty-two separate modules and implements eight different behavior modes. This paper describes the integration of SMART into the ARMMS system.
Date:
July 20, 1999
Creator:
Anderson, Robert J. & Shirey, David L.
Object Type:
Article
System:
The UNT Digital Library
Processing of CuInSe{sub 2}-based solar cells: Characterization of deposition processes in terms of chemical reaction analyses. Phase 2 Annual Report, 6 May 1996--5 May 1997
This report describes research performed by the University of Florida during Phase 2 of this subcontract. First, to study CIGS, researchers adapted a contactless, nondestructive technique previously developed for measuring photogenerated excess carrier lifetimes in SOI wafers. This dual-beam optical modulation (DBOM) technique was used to investigate the differences between three alternative methods of depositing CdS (conventional chemical-bath deposition [CBD], metal-organic chemical vapor deposition [MOCVD], and sputtering). Second, a critical assessment of the Cu-In-Se thermochemical and phase diagram data using standard CALPHAD procedures is being performed. The outcome of this research will produce useful information on equilibrium vapor compositions (required annealing ambients, Sex fluxes from effusion cells), phase diagrams (conditions for melt-assisted growth), chemical potentials (driving forces for diffusion and chemical reactions), and consistent solution models (extents of solid solutions and extending phase diagrams). Third, an integrated facility to fabricate CIS PV devices was established that includes migration-enhanced epitaxy (MEE) for deposition of CIS, a rapid thermal processing furnace for absorber film formation, sputtering of ZnO, CBD or MOCVD of CdS, metallization, and pattern definition.
Date:
October 20, 1999
Creator:
Anderson, T.
Object Type:
Report
System:
The UNT Digital Library
Potential for Waste Stratification from Back-Dilution in Tank 241-SY-101
Since late 1997, the floating crust layer in Hanford Tank 241-SY-101 (SY-101) has grown about two meters by gas accumulation. To reverse crust growth and reduce its retained gas volume, the waste in SY-101 will be diluted by transferring at least 300,000 gal of waste out of the tank and replacing it with water. In the fall of 1999, approximately 100,000 gal of this waste will be transferred into Tank SY-102; within a few days of that initial transfer, approximately 100,000 gal of water will be added to SY-101. This initial back-dilution is being planned to ensure that the base of the floating crust layer will be lifted away from the mixer pump inlet with minimal effect on the crust itself. The concern is that the added water will pool under the crust, so the resulting fluid mixture will be too light to lift the crust away from the mixer pump and dissolution at the crust base could cause unwanted gas release. To ensure sufficient mixing to prevent such stratification, water will be added near the tank bottom either through an existing sparge ring on the base of the mixer pump or through the dilution line at the inlet of …
Date:
October 20, 1999
Creator:
Antoniak, Z.I. & Meyer, P.A.
Object Type:
Report
System:
The UNT Digital Library
Extracellular iron-sulfur precipitates from growth of Desulfovibrio desulfuricans
The authors have examined extracellular iron-bearing precipitates resulting from the growth of Desulfovibrio desulfuricans in a basal medium with lactate as the carbon source and ferrous sulfate. Black precipitates were obtained when D. desulfuricans was grown with an excess of FeSO{sub 4}. When D. desulfuricans was grown under conditions with low amounts of FeSO{sub 4}, brown precipitates were obtained. The precipitates were characterized by iron K-edge XAFS (X-ray absorption fine structure), {sup 57}Fe Moessbauer-effect spectroscopy, and powder X-ray diffraction. Both were noncrystalline and nonmagnetic (at room temperature) solids containing high-spin Fe(III). The spectroscopic data for the black precipitates indicate the formation of an iron-sulfur phase with 6 nearest S neighbors about Fe at an average distance of 2.24(1) {angstrom}, whereas the brown precipitates are an iron-oxygen-sulfur phase with 6 nearest O neighbors about Fe at an average distance of 1.95(1) {angstrom}.
Date:
December 20, 1999
Creator:
Antonio, M. R.; Tischler, M. L. & Witzcak, D.
Object Type:
Article
System:
The UNT Digital Library
Dialkylenecarbonate-Bridged Polysilsesquioxanes. Hybrid Organic-Inorganic Sol-Gels with a Thermally Labile Bridging Group
In this paper, we introduce a new approach for altering the properties of bridged polysilsesquioxane xerogels using post-processing mobilization of the polymeric network. The bridging organic group contains latent functionalities that can be liberated thermally, photochemically, or by chemical means after the gel has been processed to a xerogel. These modifications can produce changes in density, volubility, porosity, and or chemical properties of the material. Since every monomer possesses two latent functional groups, the technique allows for the introduction of high levels of functionality in hybrid organic-inorganic materials. Dialkylenecarbonate-bridged polysilsesquioxane gels were prepared by the sol-gel polymerization of bis(triethoxysilylpropyl)carbonate (1) and bis(triethoxysilylisobutyl)-carbonate (2). Thermal treatment of the resulting non-porous xerogels and aerogels at 300-350 C resulted in quantitative decarboxylation of the dialkylenecarbonate bridging groups to give new hydroxyalkyl and olefinic substituted polysilsesquioxane monolithic xerogels and aerogels that can not be directly prepared through direct sol-gel polymerization of organotrialkoxysilanes.
Date:
July 20, 1999
Creator:
Assink, Roger A.; Baugher, Brigitta M.; Beach, James V.; Loy, Douglas A.; Shea, Kenneth J.; Small, James H. et al.
Object Type:
Article
System:
The UNT Digital Library
Non-Classical Smoothening of Nano-Scale Surface Corrugations
We report the first experimental observation of non-classical morphological equilibration of a corrugated crystalline surface. Periodic rippled structures with wavelengths of 290-550 nm were made on Si(OO1) by sputter rippling and then annealed at 650 - 750 °C. In contrast to the classical exponential decay with time, the ripple amplitude, A<sub>{lambda}</sub>(t), followed an inverse linear decay, A<sub>{lambda}</sub>(t)= A<sub>{lambda}</sub>(0)/(1 +k<sub>{lambda}</sub>t), agreeing with a prediction of Ozdemir and Zangwill. We measure the activation energy for surface relaxation to be 1.6±0.2 eV, consistent with an interpretation that dimers mediate transport.
Date:
May 20, 1999
Creator:
Aziz, Michael J.; Chason, Eric; Erlebacher, Jonah; Floro, Jerrold A. & Sinclair, Michael B.
Object Type:
Article
System:
The UNT Digital Library
Adaptive Spindle Balancing Using Magnetically Levitated Bearings
A technological break through for supporting rotating shafts is the active magnetic bearing (AMB). Active magnetic bearings offer some important advantages over conventional ball, roller or journal bearings such as reduced frictional drag, no physical contact in the bearing, no need for lubricants, compatibility with high vacuum and ultra-clean environments, and ability to control shaft position within the bearing. The disadvantages of the AMB system are the increased cost and complexity, reduced bearing stiffness and the need for a controller. Still, there are certain applications, such as high speed machining, biomedical devices, and gyroscopes, where the additional cost of an AMB system can be justified. The inherent actuator capabilities of the AMB offer the potential for active balancing of spindles and micro-shaping capabilities for machine tools, The work presented in this paper concentrates on an AMB test program that utilizes the actuator capability to dynamically balance a spindle. In this study, an unbalanced AMB spindle system was enhanced with an LMS (Least Mean Squares) algorithm combined with an existing PID (proportional, integral, differential) control. This enhanced controller significantly improved the concentricity of an intentionally unbalanced shaft. The study included dynamic system analysis, test validation, control design and simulation, as well …
Date:
September 20, 1999
Creator:
BARNEY,PATRICK S.; LAUFFER,JAMES P.; PETTEYS,REBECCA; REDMOND,JAMES M. & SULLIVAN,WILLIAM N.
Object Type:
Article
System:
The UNT Digital Library
Growth of InSb on GaAs Using InAlSb Buffer Layers
We report the growth of InSb on GaAs using InAlSb buffers of high interest for magnetic field sensors. We have grown samples by metal-organic chemical vapor deposition consisting of {approximately} 0.55 {micro}m thick InSb layers with resistive InAlSb buffers on GaAs substrates with measured electron nobilities of {approximately}40,000 cm{sup 2}/V.s. We have investigated the In{sub 1{minus}x}Al{sub x}Sb buffers for compositions x{le}0.22 and have found that the best results are obtained near x=0.12 due to the tradeoff of buffer layer bandgap and lattice mismatch.
Date:
September 20, 1999
Creator:
BIEFELD, ROBERT M. & PHILLIPS, JAMIE D.
Object Type:
Article
System:
The UNT Digital Library
500 CFM portable exhauster temperature and humidity analysis
500 cfm portable exhausters will be utilized on single shell tanks involved in saltwell pumping. This will be done, in part, to remove flammable gases from the tank vapor space. The exhaust filter train, fan, stack, and associated instrumentation and equipment are mounted on a portable skid. The design analysis and basis for the skid system design are documented in reference 1. A pumped drainage collection system is being added to the existing portable exhausters. Additional equipment and instrumentation are also being added to the exhausters, including a vacuum pump cabinet and a generic effluent monitoring system (GEMS). The GEMS will provide sampling and monitoring capabilities. The purpose of this analysis is three fold. First, to determine the maximum saltwell tank vapor space temperature. Second, to determine an allowable exhauster inlet air temperature increase to ensure the humidity is less than 70%. Third, to assess potential adverse temperature effects to the continuous air monitor (CAM) sample head. The results of this analysis will be used to ensure that air stream temperatures in the portable exhausters are increased sufficiently to prevent condensation from forming on either the pre or HEPA filters without adversely effecting the CAM.
Date:
May 20, 1999
Creator:
BIELICKI, B.E.
Object Type:
Report
System:
The UNT Digital Library
Project management plan for low-level mixed waste and greater-than-category 3 waste per tri-party agreement M-91-10
The objective of this project management plan is to define the tasks and deliverables that will support the treatment, storage, and disposal of remote-handled and large container contact-handled low-level mixed waste, and the storage of Greater-thaw category 3 waste. The plan is submitted to fulfill the requirements of the Hanford Federal Facility Agreement and Consent Order Milestone M-91-10, The plan was developed in four steps: (1) the volumes of the applicable waste streams and the physical, dangerous, and radioactive characteristics were established using existing databases and forecasts; (2) required treatment was identified for each waste stream based on land disposal restriction treatment standards and waste characterization data; (3) alternatives for providing the required treatment were evaluated and the preferred options were selected; (4) an acquisition plan was developed to establish the technical, schedule, and cost baselines for providing the required treatment capabilities. The major waste streams are tabulated, along with the required treatment for disposal.
Date:
May 20, 1999
Creator:
BOUNINI, L.
Object Type:
Report
System:
The UNT Digital Library
ROCK FALL CALCULATIONS FOR SINGLE CORROSION RESISTANT MATERIAL WASTE PACKAGES
The purpose of this activity is to determine the structural performance of waste packages (WP) subject to rock fall design basis event (DBE) dynamic loads and document the calculation results that describe the threshold rock sizes for crack-initiation and through-cracks in waste package shells. This activity is associated with the waste package design. AP-3.12Q, Revision 0, ICN 0, Calculations, is used to develop the calculation.
Date:
September 20, 1999
Creator:
Bader, S.
Object Type:
Report
System:
The UNT Digital Library