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The development of precipitated iron catalysts with improved stability
The objective of this program is to identify the chemical principles governing the deactivation of precipitated iron catalysts during Fischer-Tropsch synthesis and to use these chemical principles in the design of catalysts suitable for slurry reactors. The performance targets are 88% CO+H{sub 2} conversion with less than 1% deactivation/day for 1 month and a methane and ethane selectivity of no more than 7% (based on hydrocarbons and oxygenates only) at a space velocity of at least 2 normal liters per hr per gram iron (NL/hr/gFe) using a synthesis gas with 0.5-1.0 H{sub 2}:CO ratio in a slurry reactor.
Date:
May 6, 1992
Creator:
Abrevaya, H.
Object Type:
Report
System:
The UNT Digital Library
Resource capture by single leaves
Leaves show a variety of strategies for maximizing CO{sub 2} and light capture. These are more meaningfully explained if they are considered in the context of maximizing capture relative to the utilization of water, nutrients and carbohydrates reserves. There is considerable variation between crops in their efficiency of CO{sub 2} and light capture at the leaf level. Understanding of these mechanisms indicate some ways in which efficiency of resource capture could be level cannot be meaningfully considered without simultaneous understanding of implications at the canopy level. 36 refs., 5 figs., 1 tab.
Date:
May 1, 1992
Creator:
Long, S.P.
Object Type:
Article
System:
The UNT Digital Library
An update on passive correctors for the SSC dipole magnets
The concept of correction of the magnetization sextupole became a topic of discussion as soon as it was realized that superconductor magnetization could have a serious effect on the SSC beam during injection. Several methods of correction were proposed. These included (1) correction with active bore tube windings like those on the HERA machine which correct out magnetization sextupole and the sextupole due to iron saturation, (2) correction with persistent sextupole windings mounted on the bore tube (3) correction using passive superconductor (4) correction using ferromagnetic material, and (5) correction using oriented magnetized materials. This report deals with the use of passive superconductor to correct the magnetization sextupole. Two basic methods are explored in this report: (1) One can correct the magnetization sextupole by changing the diameter of the superconductor filaments in one or more blocks of the SSC dipole. (2) One can correct the magnetization sextupole and decapole by mounting passive superconducting wires on the inside of the SSC dipole coil bore. In addition, an assessment of the contribution of each conductor in the dipole to the magnetization sextupole and decapole is shown. 38 refs, 25 figs., 15 tabs.
Date:
May 1, 1991
Creator:
Green, Michael A.
Object Type:
Report
System:
The UNT Digital Library
A Program of FRC Theory Research Annual Report
At the request of the Office of Fusion Energy, a group of experts was convened on February 6--8, 1990. This group met to assess the world data base on Reversed Field Pinch (RFP) physics, and, further, to assess the role of the ZTH experiment in providing reactor relevant physics understanding for that confinement geometry. This group met, analyzed some of the relevant literature, and heard extensive presentations on the physics of the RFP and the plans for the ZTH and RFX devices. The conclusions of this group of experts are contained in this report.
Date:
May 18, 1990
Creator:
Krall, Nicholas A.
Object Type:
Report
System:
The UNT Digital Library
Site Specific Verification Guidelines.
The Bonneville Power Administration (BPA) and the Northwest region have moved from energy surplus to a time when demand for energy is likely to exceed available supplies. The Northwest Power Planning Council is calling for a major push to acquire new resources.'' To meet anticipated loads in the next decade, BPA and the region must more than double that rate at which we acquire conservation resources. BPA hopes to achieve some of this doubling by programs independently designed and implemented by utilities and other parties without intensive BPA involvement. BPA will accept proposals for programs using performance-based payments, in which BPA bases its reimbursement to the sponsor on measured energy savings rather than program costs. To receive payment for conservation projects developed under performance-based programs, utilities and other project developers must propose verification plans to measure the amount of energy savings. BPA has traditionally used analysis of billing histories, before and after measure installation, adjusted by a comparison group on non-participating customers to measure conservation savings. This approach does not work well for all conversation projects. For large or unusual facilities the comparison group approach is not reliable due to the absence of enough comparable non-participants to allow appropriate statistical …
Date:
May 1, 1992
Creator:
Harding, Steve; Gordon, Frederick M. & Kennedy, Mike
Object Type:
Report
System:
The UNT Digital Library
Repair Welding of Fusion Reactor Components
Recent experimental investigations indicate that the repair welding of irradiated materials containing greater than 1 to 2.5 appm helium leads to catastrophic cracking in the heat affected zone of the weld. The high temperatures and cooling tensile stresses which occur during the welding process lead to enhanced helium bubble growth in the heat affected zone region, resulting in catastrophic cracking upon cooling. An investigation is proposed which seeks to determine the effect of stress state on the helium bubble growth process and develop engineering modifications to the welding process based upon this understanding in an attempt to alleviate or eliminate the weld cracking problem in type 316 stainless steel materials.
Date:
May 20, 1992
Creator:
Chin, Bryan A.
Object Type:
Report
System:
The UNT Digital Library
Investigation of joining techniques for advanced austenitic alloys
Modified Alloys 316 and 800H, designed for high temperature service, have been developed at Oak Ridge National Laboratory. Assessment of the weldability of the advanced austenitic alloys has been conducted at the University of Tennessee. Four aspects of weldability of the advanced austenitic alloys were included in the investigation.
Date:
May 1, 1991
Creator:
Lundin, C. D.; Qiao, C. Y. P.; Kikuchi, Y.; Shi, C. & Gill, T. P. S.
Object Type:
Report
System:
The UNT Digital Library
Milliwatt Generator Project
This report covers progress on the Milliwatt Generator Project from April 1986 through March 1988. Activities included fuel processing and characterization, production of heat sources, fabrication of pressure-burst test units, compatibility studies, impact testing, and examination of surveillance units. The major task of the Los Alamos Milliwatt Generator Project is to fabricate MC2893A heat sources (4.0 W) for MC2730A radioisotope thermoelectric generators (RTGS) and MC3599 heat sources (4.5 W) for MC3500 RTGs. The MWG Project interfaces with the following contractors: Sandia National Laboratories, Albuquerque (designer); E.I. du Pont de Nemours and Co. (Inc.), Savannah River Plant (fuel); Monsanto Research Corporation, Mound Facility (metal hardware); and General Electric Company, Neutron Devices Department (RTGs). In addition to MWG fabrication activities, Los Alamos is involved in (1) fabrication of pressure-burst test units, (2) compatibility testing and evaluation, (3) examination of surveillance units, and (4) impact testing and subsequent examination of compatibility and surveillance units.
Date:
May 1, 1992
Creator:
Latimer, T.W. & Rinehart, G.H.
Object Type:
Report
System:
The UNT Digital Library
Operating experience with the ALS linac
The linac injector for the Advanced Light Source (ALS) at LBL was recently put into operation. Energy is 50 MeV, frequency 3 GHz. The electron gun delivers up to 6nC in a 3.0-ns bunch at 120 kV. A train of bunches is injected into a 1-Hz booster and accelerated to 1.5 GHz for storage ring injection. A magnetic analysis system is used for optimizing the linac. Measured beam properties from the gun and after acceleration in the linac are described. 9 refs., 3 figs.
Date:
May 1, 1991
Creator:
Selph, F. & Massoletti, D.
Object Type:
Article
System:
The UNT Digital Library
Growth, preparation, and dielectric properties of monodomain single crystal PbTiO sub 3
A method is described for obtaining monodomain PbTiO{sub 3} single crystals with high electrical resistivity (10{sup 10}{Omega} cm) and low dielectric frequency dispersion. The single crystals of PbTiO{sub 3} were grown by flux solution method. Space charge related defects, which result in the large dielectric frequency dispersion, were eliminated by heat treatments. 90{degrees} domains were removed by applying a unidirectional compressive stress along the <100> crystallographic direction. The monodomain single crystals of PbTiO{sub 3} were identified by cross polarized light optical microscopy and by X-ray diffraction (rocking curve). The anisotropic dielectric constants of these high quality single crystals were measured as a function of temperature. The results differ from the data reported previously in the literature.
Date:
May 1, 1992
Creator:
Li, Z.; Xu, X. Z.; Dai, X. H.; Lam, D. J. & Chan, S. K.
Object Type:
Article
System:
The UNT Digital Library
The use of synchrotron radiation for the analysis of coal combustion products
An understanding of the chemical composition of such slags under boiler operating conditions and as function of the mineral composition of various coals is the ultimate goal of this program. The experiment involves scanning through the K- or L-shell absorption edge of the element in question. The structure of the absorption edge, consisting of transitions to unoccupied molecular levels, can be compared to those of model compounds for identification. The relative position of the absorption edge can yield information regarding the oxidation state of the element. This portion is the X-ray Absorption Near Edge Structure (XANES) portion of the spectrum. The Extended X-ray Absorption Fine Structure (EXFAS) region, extending from about 60 eV above the absorption edge, represents scattering from neighboring constituents and can be used to determine the coordination number of coordination distance of a specific element from its neighboring atoms. The best source of excitation energy for these experiments is an electron storage ring emitting synchrotron radiation (SR). The National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory is a 2.5 GeV storage ring and emits a continuous spectrum of x rays to an energy of about 30 keV. Beam line X-19A is dedicated to XANES and EXAFS …
Date:
May 1, 1992
Creator:
Manowitz, B. & Gordon, B.
Object Type:
Article
System:
The UNT Digital Library
Effects of catalytic mineral matter on CO/CO sub 2 , temperature and burning time for char combustion
The temperature of a char particle burning in an oxygen containing atmosphere is the product of a strongly coupled balance between particle size and physical properties, heat transfer from the particle, surface reactivity, CO/CO{sub 2} ratio and gas phase diffusion in the surrounding boundary layer and within the particle. CO{sub 2}/CO ratios can be strongly influenced by catalytic material in the carbon and by the char temperature. In this program we are measuring the CO{sub 2}/CO ratio for both catalyzed and uncatalyzed chars over a wide range of temperature. These results will then be used to develop predictive models for char temperature and burning rates. The electrodynamic balance has been successfully used to make such measurements for single 200{mu}m spherocarb particles. A few theoretical approaches to model a single particle oxidation have been made, but most of them assumed the infinitely thin reaction zone at the particle surface. This approach can not explain pore diffusion limitation, structural change, or reaction at low temperatures inside the particle. Too simplifying solid phase reaction may leads to wrong predictions. In this report, progress on constructing models including both solid and gas phase reaction are reported.
Date:
May 4, 1992
Creator:
Longwell, J. P.; Sarofim, A. F.; Lee, Chun-Hyuk & Modestino, A. J.
Object Type:
Report
System:
The UNT Digital Library
Manufactured Homes Acquisition Program : Heat Loss Assumptions and Calculations, Heat Loss Coefficient Tables.
This manual is intended to assist builders of manufactured homes in assessing the thermal performance of structural components used in the Manufactured Housing Acquisition Program (MAP) sponsored by the Bonneville Power Administration (BPA). U-factors for these components are calculated using the ASHRAE (1989) parallel heat loss method, with adaptations made for the construction practices found in the Pacific Northwest manufactured home industry. This report is divided into two parts. The first part describes the general assumptions and calculation procedures used to develop U-factors and R-values for specific materials used in the construction industry, overall U-factors for component sections, and the impact of complex framing and thermal configurations on various components' heat loss rates. The individual components of manufactured homes are reviewed in terms of overall thermal conductivity. The second part contains tables showing the results of heat loss calculations expressed as U-factors for various configurations of the major building components: floor systems, ceiling systems, wall systems, windows, doors and skylights. These values can be used to establish compliance with the MAP specifications and thermal performance criteria or to compare manufactured homes built to different standards.
Date:
May 1, 1992
Creator:
Davis, Bob & Baylon, David
Object Type:
Report
System:
The UNT Digital Library
Surfaces and Thin Films Studied by Picosecond Ultrasonics
This research is the study of thin films and interfaces via the use of the picosecond ultrasonic technique. In these experiments ultrasonic waves are excited in a structure by means of a picosecond light pulse ( pump pulse''). The propagation of these waves is detected through the use of a probe light pulse that is time-delayed relative to the pump. This probe pulse measures the change {Delta}R(t) in the optical reflectivity of the structure that occurs because the ultrasonic wave changes the optical properties of the structure. This technique make possible the study of the attenuation and velocity of ultrasonic waves up to much higher frequencies than was previously possible (up to least 500 GHz). In addition, the excellent time-resolution of the method makes it possible to study nanostructures of linear dimensions down to 100 {Angstrom} or less by ultrasonic pulse-echo techniques. 25 refs.
Date:
May 1, 1992
Creator:
Maris, J. H. & Tauc, J.
Object Type:
Report
System:
The UNT Digital Library
Comparative mutagenesis of human cells in vivo and in vitro
This report discusses measuring methods of point mutations; high density cell cultures for low dose studies; measurement and sequence determination of mutations in DNA; the mutational spectra of styrene oxide and ethlyene oxide in TK-6 cells; mutational spectrum of Cr in human lymphoblast cells; mutational spectra of radon in TK-6 cells; and the mutational spectra of smokeless tobacco. (CBS)
Date:
May 1, 1992
Creator:
Thilly, W.G.
Object Type:
Report
System:
The UNT Digital Library
Fundamental spectroscopic studies of carbenes and hydrocarbon radicals
This document details activities during this reporting period topics discussed are: The first spectroscopic identification of the HCCCO and DCCCO radicals; detection of new vibrationally excited states of the carbon chain radicals CCH and CCD and the three-membered carbene ring, cyclopropenylidene; determination of an accurate structure of the cumulene carbene H{sub 2}CCC; analysis the hyperfine structure in the SiC radical; and the undertaking of a systematic search for new sulfur bearing radicals.
Date:
May 1, 1992
Creator:
Thaddeus, P. & Gottlieb, C.
Object Type:
Report
System:
The UNT Digital Library
Wolf Point Substation, Roosevelt County, Montana
The Western Area Power Administration (Western), an agency of the United States Department of Energy, is proposing to construct the 115-kV Wolf Point Substation near Wolf Point in Roosevelt County, Montana (Figure 1). As part of the construction project, Western's existing Wolf Point Substation would be taken out of service. The existing 115-kV Wolf Point Substation is located approximately 3 miles west of Wolf Point, Montana (Figure 2). The substation was constructed in 1949. The existing Wolf Point Substation serves as a Switching Station'' for the 115-kV transmission in the region. The need for substation improvements is based on operational and reliability issues. For this environmental assessment (EA), the environmental review of the proposed project took into account the removal of the old Wolf Point Substation, rerouting of the five Western lines and four lines from the Cooperatives and Montana-Dakota Utilities Company, and the new road into the proposed substation. Reference to the new proposed Wolf Point Substation in the EA includes these facilities as well as the old substation site. The environmental review looked at the impacts to all resource areas in the Wolf Point area. 7 refs., 6 figs.
Date:
May 1, 1991
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Recent experimental studies on Hadron showers produced in high energy muon-nucleus interactions
The Fermilab Tevatron Muon Experiment has analyzed the hadron showers of events resulting from the scattering of a muon beam (< E{sub {mu}} > = 490 GeV) off H{sub 2}, D{sub 2} and Xenon targets. The topics which will be discussed are: (1) space-time evolution of the hadronization process; (2) leading hadron distributions in the shadowing region; (3) rates and characteristics of 3-jet events. 23 refs.
Date:
May 1, 1992
Creator:
Morfin, J.
Object Type:
Article
System:
The UNT Digital Library
Conduct of operations: The foundation of safety -- An overview
This paper discusses issues and approaches dealing with conceptualizing, implementing, and maintaining configuration control commensurate with the conduct of operations approach defined by DOE ORDER 5480.19. Specific topics reviewed will include key elements of assessments to determine the status quo such as assessment criteria, assessment personnel, and assessment scope; administrative programs to maintain the status quo such as organizational definition, responsibilities, interfaces, and priorities; oversight to determine control effectiveness via compliance and performance assessment.
Date:
May 1, 1992
Creator:
Willett, D.J. & Hertel, N.E.
Object Type:
Article
System:
The UNT Digital Library
Laser diagnostics of H sup minus formation in a magnetic multicusp ion source
The populations of ground electronic state atomic hydrogen and ground electronic state, vibrationally-rotationally excited hydrogen molecules in a negative hydrogen ion source discharge have been measured using vacuum ultraviolet (VUV) laser absorption spectroscopy. Vibrational states up to v=8 and rotational levels as high as J=15 have been measured. The measurements have been made under a range of discharge conditions. The complete vibrational population distribution for v=1-8, J=1 has been obtained. The vibrational distribution appears to be thermalized and does not exhibit a plateau'' at the higher vibrational levels, in contrast to most models of this system. In contrast, the high rotational states are populated suprathermally. These determinations indicate that rotationally excited molecules may play an important role in the production of H{sup minus} in these sources. 5 refs., 5 figs.
Date:
May 1, 1991
Creator:
Young, A. T.; Chen, P.; Kunkel, W. B.; Leung, K. N.; Li, C. Y. & Stutzin, G. C.
Object Type:
Article
System:
The UNT Digital Library
Static magnetic fields: A summary of biological interactions, potential health effects, and exposure guidelines
Interest in the mechanisms of interaction and the biological effects of static magnetic fields has increased significantly during the past two decades as a result of the growing number of applications of these fields in research, industry and medicine. A major stimulus for research on the bioeffects of static magnetic fields has been the effort to develop new technologies for energy production and storage that utilize intense magnetic fields (e.g., thermonuclear fusion reactors and superconducting magnet energy storage devices). Interest in the possible biological interactions and health effects of static magnetic fields has also been increased as a result of recent developments in magnetic levitation as a mode of public transportation. In addition, the rapid emergence of magnetic resonance imaging as a new clinical diagnostic procedure has, in recent years, provided a strong rationale for defining the possible biological effects of magnetic fields with high flux densities. In this review, the principal interaction mechanisms of static magnetic fields will be described, and a summary will be given of the present state of knowledge of the biological, environmental, and human health effects of these fields.
Date:
May 1, 1992
Creator:
Tenforde, T.S.
Object Type:
Article
System:
The UNT Digital Library
International research into chlorofluorocarbon (CFC) alternatives
Selected researchers from 21 countries were queried through questionnaires about their current and planned research activities. The results of the survey show that the majority of research being conducted by the respondents is devoted to investigating the hydrogenated fluorocarbon HFC-134a as a replacement for CFC-12 in refrigeration applications. The main issue with this alternative is identifying compatible lubricants that do not reduce its effectiveness.
Date:
May 1, 1992
Creator:
Marseille, T. J.; Shankle, D. L. & Thurman, A. G.
Object Type:
Report
System:
The UNT Digital Library
Effect of Au on the reliability of fine pitch surface mount solder joints
The effect of Au on the reliability of 0.65 mm pitch surface mount solder joints between plastic quad flat packs and Cu-Ni-Au FR-4 printed circuit boards was investigated. Cu-Ni-Au is a desirable printed circuit board finish for multi-chip modules or printed circuit boards that would otherwise require a selective Au finish, for example for edge connectors or wire bondable parts. However, Au is known to embrittle solder when it is present in sufficiently high concentrations, creating a concern that solder joint fatigue life in service will also be adversely affected. This paper reports the results of mechanical shock, mechanical vibration and thermal cycling testing of fine pitch solder joints containing varying amounts of Au. Tests were performed on as-soldered joints and on joints that had been heat-treated to evolve the microstructure toward equilibrium. The tests were designed to accelerate in-service conditions in a typical industrial environment. Under these conditions, the Au concentrations tested did not promote solder joint failures. Microstructural characterization of the distribution and morphology of the Au-, Ni-, and Cu-Sn intermetallics in the joint before and after accelerated testing was also performed. On the basis of these observations it is recommended that the Au concentration in solder joints …
Date:
May 1, 1991
Creator:
Glazer, J. (Hewlett-Packard Co., Palo Alto, CA (United States)); Kramer, P. & Morris, J.W. Jr. (Lawrence Berkeley Lab., CA (United States))
Object Type:
Article
System:
The UNT Digital Library
Superconducting final focus for the SLAC Linear Collider
Triplets composed of superconducting quadrupoles have been built and installed as the final focusing element for the high-energy positron and electron beams of the SLAC Linear Collider. Special features include independent alignment to 100-micron tolerance inside a common cryostat; non-magnetic materials to allow operation inside the detector's solenoid field; a continuous-flow helium-only system using 50-meter-long flexible transfer lines; and complete operation of the system before installation. The mechanical design and cryogenic operation experience are presented.
Date:
May 1, 1992
Creator:
Ash, W.W.; Barrera, F.; Burgess, W.; Cook, K.; Cutler, H.; Ferrie, J. et al.
Object Type:
Article
System:
The UNT Digital Library