Resource Type

MHD computation of feedback of resistive-shell instabilities in the reversed field pinch (open access)

MHD computation of feedback of resistive-shell instabilities in the reversed field pinch

MHD computation demonstrates that feedback can sustain reversal and reduce loop voltage in resistive-shell reversed field pinch (RFP) plasmas. Edge feedback on {approximately}2R/a tearing modes resonant near axis is found to restore plasma parameters to nearly their levels with a close-fitting conducting shell. When original dynamo modes are stabilized, neighboring tearing modes grow to maintain the RFP dynamo more efficiently. This suggests that experimentally observed limits on RFP pulselengths to the order of the shell time can be overcome by applying feedback to a few helical modes.
Date: May 1, 1992
Creator: Zita, E.J.; Prager, S.C. (Wisconsin Univ., Madison, WI (United States). Plasma Physics Research); Ho, Y.L. & Schnack, D.D (Science Applications International Corp., San Diego, CA (United States))
System: The UNT Digital Library
Kinematics of Compton backscattering x-ray source for angiography (open access)

Kinematics of Compton backscattering x-ray source for angiography

Calculations of X-Ray production rates, energy spread, and spectrum of Compton-backscattered photons from a Free Electron Laser on an electron beam in a low energy (136-MeV) compact (8.5-m circumference) storage ring indicate that an X-Ray intensity of 34.6 10{sup 7} X-Ray photons per 0.5-mm {times} 0.5-mm pixel for Coronary Angiography near the 33.169-keV iodine K-absorption edge can be achieved in a 4-msec pulse within a scattering cone of 1-mrad half angle. This intensity, at 10-m from the photon-electron interaction point to the patient is about a factor of 10 larger than presently achieved from a 4.5-T superconducting wiggler source in the NSLS 2.5-GeV storage ring and over an area about 5 times larger. The 2.2-keV energy spread of the Compton-backscattered beam is, however, much larger than the 70-eV spread presently attained form the wiggler source and use of a monochromator. The beam spot at the 10-m interaction point-to-patient distance is 20-mm diameter; larger spots are attainable at larger distances but with a corresponding reduction in X-Ray flux. Such a facility could be an inexpensive clinical alternative to present methods of non-invasive Digital Subtraction Angiography (DSA), small enough to be deployed in an urban medical center, and could have other medical, …
Date: May 1, 1992
Creator: Blumberg, L.N.
System: The UNT Digital Library
Steam foam studies in the presence of residual oil (open access)

Steam foam studies in the presence of residual oil

The lack of understanding regarding foam flow in porous media necessitates further research. This paper reports on going work at Stanford University aimed at increasing our understanding in the particular area of steam foams. The behavior of steam foam is investigated with a one dimensional (6 ft. {times} 2.15 in.) sandpack under residual oil conditions of approximately 12 percent. The strength of the in-situ generated foam, indicated by pressure drops, is significantly affected by injection procedure, slug size, and steam quality. The surfactant concentration effect is minor in the range studied. In the presence of residual oil the simultaneous injection of steam and surfactant fails to generate foam in the model even though the same procedure generates a strong foam in the absence of oil. Nevertheless when surfactant is injected as a slug ahead of the steam using a surfactant alternating (SAG) procedure, foam is generated. The suggested reason for the success of SAG is the increased phase mixing that results from steam continually having to reestablish a path through a slug of surfactant solution.
Date: May 1, 1992
Creator: Hutchinson, D.A.; Demiral, B. & Castanier, L.M.
System: The UNT Digital Library
A surface definition code for turbine blade surfaces (open access)

A surface definition code for turbine blade surfaces

A numerical interpolation scheme has been developed for generating the three-dimensional geometry of wind turbine blades. The numerical scheme consists of (1) creating the frame of the blade through the input of two or more airfoils at some specific spanwise stations and then scaling and twisting them according to the prescribed distributions of chord, thickness, and twist along the span of the blade; (2) transforming the physical coordinates of the blade frame into a computational domain that complies with the interpolation requirements; and finally (3) applying the bi-tension spline interpolation method, in the computational domain, to determine the coordinates of any point on the blade surface. Detailed descriptions of the overall approach to and philosophy of the code development are given along with the operation of the code. To show the usefulness of the bi-tension spline interpolation code developed, two examples are given, namely CARTER and MICON blade surface generation. Numerical results are presented in both graphic data forms. The solutions obtained in this work show that the computer code developed can be a powerful tool for generating the surface coordinates for any three-dimensional blade.
Date: May 1, 1992
Creator: Yang, S.L. (Michigan Technological Univ., Houghton, MI (United States)); Oryang, D. & Ho, M.J. (Tuskegee Univ., AL (United States))
System: The UNT Digital Library
Diosmacycloalkanes as models for the formation of hydrocarbons from surface methylenes (open access)

Diosmacycloalkanes as models for the formation of hydrocarbons from surface methylenes

We are making progress on our investigation of the mechanism of olefin exchange with Os{sub 2}(C{sub 2}H{sub 4})(CO){sub 8}. We are probing this system by kinetic study of the reaction of Os{sub 2}(C{sub 2}H{sub 4})(CO){sub 8} with butyl acrylate (BA) under various pressures of ethylene.
Date: May 1, 1992
Creator: Norton, J.R.
System: The UNT Digital Library
Yaw dynamics of horizontal axis wind turbines (open access)

Yaw dynamics of horizontal axis wind turbines

Designers of a horizontal axis wind turbine yaw mechanism are faced with a difficult decision. They know that if they elect to use a yaw- controlled rotor then the system will suffer increased initial cost and increased inherent maintenance and reliability problems. On the other hand, if they elect to allow the rotor to freely yaw they known they will have to account for unknown and random, though bounded, yaw rates. They will have a higher-risk design to trade-off against the potential for cost savings and reliability improvement. The risk of a yaw-free system could be minimized if methods were available for analyzing and understanding yaw behavior. The complexity of yaw behavior has, until recently, discouraged engineers from developing a complete yaw analysis method. The objectives of this work are to (1) provide a fundamental understanding of free-yaw mechanics and the design concepts most effective at eliminating yaw problems, and (2) provide tested design tools and guidelines for use by free-yaw wind systems manufacturers. The emphasis is on developing practical and sufficiently accurate design methods.
Date: May 1, 1992
Creator: Hansen, A.C. (Utah Univ., Salt Lake City, UT (United States))
System: The UNT Digital Library
Organ/inorganic interactions of nitrogen in oilfields: Part 1, Geochemistry (open access)

Organ/inorganic interactions of nitrogen in oilfields: Part 1, Geochemistry

A detailed investigation of the geochemistry of nitrogen in oilfields is being conducted in order to test the model that N is generated from hydrocarbons during thermal maturation and is incorporated into authigenic clay minerals in the sediments through which the oil and brines migrate. If the model is correct, there should be fixed-NH{sub 4} anomalies that can be correlated across an oilfield to indicate the pathway of migration into the trap. The preliminary data from this research shows that fixed-NH{sub 4} anomalies are associated with producing intervals in twelve cores examined across a multi-reservoir oilfield. Trends in fixed-NH{sub 4} values across the field do not reflect present brine NH{sub 4}{sup +} concentrations. Fixed-NH{sub 4} anomalies are greatest in the structurally high areas of the anticlinal trap, while brine NH{sub 4}{sup +} concentrations are greatest near a fault that is a likely entry point for oil into the trap. Limited isotopic data show {approximately}3% variation in {delta}{sup 15}N across one reservoir with the heavier values found in the same well as the maximum fixed-NH{sub 4} anomalies.
Date: May 1992
Creator: Williams, Lynda B.
System: The UNT Digital Library
Unix version of CALOR89 for calorimeter applications (open access)

Unix version of CALOR89 for calorimeter applications

CALOR89 is a system of coupled Monte Carlo particle transport computer codes which has been successfully employed for the estimation of calorimeter parameters in High Energy Physics. In the past CALOR89 has been running on various IBM machines and on CRAY X-MP at Lawrence Livermore Lab. These machines had non-unix operating systems. In this report we present a UNIX version of CALOR89, which is especially suited for the UNIX work stations. Moreover CALOR89 is also been supplemented with two new program packages which makes it more user friendly. CALPREP is a program for the preparation of the input files for CALOR89 in general geometry and ANALYZ is an analysis package to extract the final results from CALOR89 relevant to calorimeters. This report also provides two script files LCALOR and PCALOR. LCALOR runs CALOR89 sequences of programs and EGS4 for a given configuration sequentially on a single processor and PCALOR concurrently on a multiprocessor unix workstation.
Date: May 12, 1992
Creator: Handler, T. (Tennessee Univ., Knoxville, TN (United States). Dept. of Physics and Astronomy); Job, P.K.; Price, L.E. (Argonne National Lab., IL (United States). High Energy Physics Div.) & Gabriel, T.A. (Oak Ridge National Lab., TN (United States))
System: The UNT Digital Library
The use of ARM data to test an improved parameterization of upper tropospheric clouds for use in climate models (open access)

The use of ARM data to test an improved parameterization of upper tropospheric clouds for use in climate models

We have proposed to provide and further develop an advanced finite-difference climate model for use in CHAMMP. The model includes advanced parameterizations of cumulus convection, boundary-layer processes, cloud formation, and land-surface vegetation, as well as parameterizations of radiative transfer and gravity wave drag. Postprocessing codes and a user's guide will also be provided.
Date: May 1992
Creator: Randall, D.A.
System: The UNT Digital Library
NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts (open access)

NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts

During this period, we focused our attention in analyzing the magnetic nature of the extensively used trimetallic catalyst system Cu-Co-Cr for the production of higher alcohols. We believe that there could be some correspondence between the catalytic and magnetic behaviors of the transition metal catalyst systems. Both the morphology and metallic charge distribution of the particles are known to govern the catalytic as well as the magnetic properties of the system.
Date: May 4, 1992
Creator: Murty, A.N.
System: The UNT Digital Library
The development of precipitated iron catalysts with improved stability (open access)

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.
System: The UNT Digital Library
National Institute for Petroleum and Energy Research 1990 annual report, October 1, 1989--September 30, 1990 (open access)

National Institute for Petroleum and Energy Research 1990 annual report, October 1, 1989--September 30, 1990

Research programs at NIPER cover a wide spectrum of specific technical tasks, all of which relate to three broad technology areas: (1) Enhanced oil recovery and all of the associated technical activities such as reservoir characterization and imaging techniques; (2) Alternative fuels evaluation and testing, including the supporting technologies of thermodynamics research and fuels characterization; (3) Environmentally technology related to production, transportation, and utilization of oil and gas.
Date: May 1, 1992
Creator: unknown
System: The UNT Digital Library
The development of precipitated iron catalysts with improved stability (open access)

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}:CP ratio in a slurry reactor.
Date: May 6, 1992
Creator: Abrevaya, H.
System: The UNT Digital Library
High resolution electron energy loss studies of surface vibrations (open access)

High resolution electron energy loss studies of surface vibrations

New experimental studies of surface vibrational properties of materials with high-resolution electron energy loss spectroscopy (EELS) are reported. This document summarizes recent progress on surface phonon dispersion measurements on copper (001); silver (001) and (111); oxygen adsorption on ultrathin films of cobalt and nickel; aluminum on silicon (111); and copper-oxide based superconductors.
Date: May 1, 1992
Creator: Kesmodel, L.L.
System: The UNT Digital Library
Research on elementary particle physics (open access)

Research on elementary particle physics

This report describes the activities of the University of Illinois Experimental High Energy Physics Group. The physicists in the University of Illinois High Energy Physics Group are engaged in a wide variety of experiments at current and future accelerator laboratories. These include: (1) The CDF experiment at the Fermilab Tevetron p{bar p} collider. (2) Design and developmental work for the SDC group at SSCL. (3) Experiments at the wide band photon beam at Fermilab. (4) The SLD experiment at SLAC and design studies for a {tau}-charm factor. (5) CP violation experiments at Fermilab. (6) The HiRes cosmic ray experiment at Dugway Proving Grounds, Utah. (7) Computational facilities. (8) Electronics systems development.
Date: May 1, 1992
Creator: Holloway, L.E. & O'Halloran, T.A.
System: The UNT Digital Library
Coal plasticity at high heating rates and temperatures (open access)

Coal plasticity at high heating rates and temperatures

The potential influence of gas bubbles on the viscosity of molten coal at elevated temperatures was estimated by calculations, using literature models for the viscosity of two and three phase suspensions. In one approach, gas bubbles in molten coal were approximated as the dispersed phase of deformable liquid globules in G.I. Taylor's model of emulsion viscosity. This model was incorporated into different models for the viscosity of solid-in-liquid suspensions, in which the dispersed solids are approximated as rigid spheres. Calculations show that in the presence of gas bubbles, the apparent viscosity of molten coal increases roughly in proportion to the volume fraction of gas with respect to the liquid continuum phase. It is experimentally and mathematically difficult to accurately determine gas volume fractions throughout the softening stage of coal pyrolysis. Our current plan is therefore to assume that the apparent viscosity of molten coal can be reasonably modeled in terms of a single liquid continuum phase and one dispersed phase consisting only of solids, using for example the two phase suspension viscosity model of Hatschek or of Frankel and Acrivos. In this approximation, gas bubble effects would force the model to underestimate metaplast concentrations and to overpredict the contribution of …
Date: May 1, 1992
Creator: Gerjarusak, S.; Peters, W.A. & Howard, J.B.
System: The UNT Digital Library
Biological Production of Ethanol From Coal (open access)

Biological Production of Ethanol From Coal

The effects of temperature on the growth and uptake of CO by C. ljundahlii were studied in batch culture. Continuous stirred tank reactor (CSTR) studies were carried out measuring the effects of agitation rate on culture performance. Finally, cell recycle studies continued in conjunction with a CSTR.
Date: May 1, 1992
Creator: unknown
System: The UNT Digital Library
NREL Solar Radiation Resource Assessment Project: Status and Outlook (open access)

NREL Solar Radiation Resource Assessment Project: Status and Outlook

This report summarizes the activities and accomplishments of NREL's Solar Radiation Resource Assessment Project during fiscal year 1991. Currently, the primary focus of the SRRAP is to produce a 1961--1990 National Solar Radiation Data Base, providing hourly values of global horizontal, diffuse, and direct normal solar radiation at approximately 250 sites around the United States. Because these solar radiation quantities have been measured intermittently at only about 50 of these sites, models were developed and applied to the majority of the stations to provide estimates of these parameters. Although approximately 93% of the data base consists of modeled data this represents a significant improvement over the SOLMET/ERSATZ 1952--1975 data base. The magnitude and importance of this activity are such that the majority of SRRAP human and financial in many other activities, which are reported here. These include the continued maintenance of a solar radiation monitoring network in the southeast United States at six Historically Black Colleges and Universities (HBCU's), the transfer of solar radiation resource assessment technology through a variety of activities, participation in international programs, and the maintenance and operation of NREL's Solar Radiation Research Laboratory. 17 refs.
Date: May 1, 1992
Creator: Renne, D.; Riordan, C.; Maxwell, E.; Stoffel, T.; Marion, B.; Rymes, M. et al.
System: The UNT Digital Library
Innovative Clean Coal Technologies (ICCT): Demonstration of innovative applications of technology for cost reductions to the CT-121 FGD process (open access)

Innovative Clean Coal Technologies (ICCT): Demonstration of innovative applications of technology for cost reductions to the CT-121 FGD process

The objective of this project is to demonstrate on a commercial scale several innovative applications of cost-reducing technology to the Chiyoda Thoroughbred-121 (CT-121) process. CT-121 is a second generation flue gas desulfurization (FGD) process which is considered by the Electric Power Research Institute (EPRI) and Southern Company Services (SCS) to be one of the most reliable and lowest cost FGD options for high-sulfur coal-fired utility boiler applications. Demonstrations of the innovative design approaches will further reduce the cost and provide a clear advantage to CT121 relative to competing technology.
Date: May 15, 1992
Creator: unknown
System: The UNT Digital Library
Evaportranspiration studies for protective barriers: FY 1989 status report (open access)

Evaportranspiration studies for protective barriers: FY 1989 status report

This document describes the results of technological developments and experiments at the Small Tube Lysimeter Facility. The objective of this research is to develop the capability to predict evapotranspiration in support of studies of water infiltration control for the Hanford Protective Barrier Development Program. Evapotranspiration is the combined loss of water from plants and soil surfaces to the atmosphere. This process must be predictable to adequately model soil water dynamics. We develop a miniature greenhouse (gas exchange chamber), where internal temperature and relative humidity can be controlled. With this device we measured evapotranspiration, transpiration, and carbon dioxide exchange rates from lysimeters with various surface and plant characteristics. We tested the effect on gas exchange rates and sand, gravel, admix, and soil surfaces in lysimeters where, cheat-grass, Bromus tectorum, had been seeded. Results showed that evapotranspiration was unaffected by the surface treatments. Estimated transpiration rates were higher for plants growing in sand compared with rates for plants growing in the admix and soil treatments. Soil evaporation rates were higher in the gravel treatment than in the sand treatment. Future research will entail parameterization of relationships between evapotranspiration, transpiration, soil evaporation, carbon dioxide exchange, and the abiotic and biotic factors that drive …
Date: May 1, 1992
Creator: Link, S.O.; Thiede, M.E.; Downs, J.L.; Lettau, D.J. (Pacific Northwest Lab., Richland, WA (United States)) & Waugh, W.J. (Geotech, Grand Junction, CO (United States))
System: The UNT Digital Library
Low-level and transuranic waste transportation, disposal, and facility decommissioning cost sensitivity analysis (open access)

Low-level and transuranic waste transportation, disposal, and facility decommissioning cost sensitivity analysis

The Systems Design Study (SDS) identified technologies available for the remediation of low-level and transuranic waste stored at the Radioactive Waste Management Complex's Subsurface Disposal Area at the Idaho National Engineering Laboratory. The SDS study intentionally omitted the costs of transportation and disposal of the processed waste and the cost of decommissioning the processing facility. This report provides a follow-on analysis of the SDS to explore the basis for life-cycle cost segments of transportation, disposal, and facility decommissioning; to determine the sensitivity of the cost segments; and to quantify the life-cycle costs of the 10 ex situ concepts of the Systems Design Study.
Date: May 1, 1992
Creator: Schlueter, R. (Bechtel National, Inc., San Francisco, CA (United States)) & Schafer, J.J. (EG and G Idaho, Inc., Idaho Falls, ID (United States))
System: The UNT Digital Library
Facility Interface Capability Assessment (FICA) summary report (open access)

Facility Interface Capability Assessment (FICA) summary report

The Office of Civilian Radioactive Waste Management (OCRWM) is responsible for developing the Civilian Radioactive Waste Management System (CRWMS) to accept spent nuclear fuel from the commercial facilities. In support of the development of the CRWMS, OCRWM sponsored the Facility Interface Capability Assessment (FICA) project. The objective of this project was to assess the capability of each commercial facility to handle various spent nuclear fuel shipping casks. The purpose of this report is to summarize the results of the facility assessments completed within the FICA project. The project was conducted in two phases. During Phase I, the data items required to complete the facility assessments were identified and the data base for the project was created. During Phase II, visits were made to 122 facilities on 76 sites to collect data and information, the data base was updated, and assessments of the cask-handling capabilities at each facility were performed.
Date: May 1, 1992
Creator: Viebrock, J. M.; Mote, N. & Pope, R. B.
System: The UNT Digital Library
Photogenerated carrier-induced reactions on uhv semiconductor surfaces (open access)

Photogenerated carrier-induced reactions on uhv semiconductor surfaces

The objective for this experimental work was to examine the reaction mechanisms, half-collision dynamics, and other optically induced chemical effects, that are operable on a well characterized single-crystal semiconductor surface. Of particular interest were reactions induced by charge transfer from the semiconductor surface including hot carrier and thermalized carrier processes. The primary technique to measure the desorbed fragment translational energies was time-of-flight mass-spectroscopy, used in conjunction with a pulsed tunable laser source. The work was carried out in ultrahigh vacuum, thus other surface spectroscopies such as temperature-programmed desorption, (TPD), (LEED), etc. were used as needed. In the project, the photoreactions of several halogen-containing molecules on GaAs(110) surfaces have been investigated. The studies have made the first observations of several new photochemical processes on uhv prepared surfaces including intermolecular charge transfer; desorption by thermal-carrier-induced reactions (including the measurement of coverage-dependent changes in the translational energies of the desorbed products); interferometric oscillation of photoinduced reactions; and self-quenching of thermal carrier reactions on surfaces.
Date: May 28, 1992
Creator: Osgood, R.M. Jr.
System: The UNT Digital Library
Hanford ferrocyanide waste chemistry and reactivity preliminary catalyst and initiator screening studies (open access)

Hanford ferrocyanide waste chemistry and reactivity preliminary catalyst and initiator screening studies

During the 1950s, ferrocyanide was used to scavenge radiocesium from aqueous nitrate-containing Hanford wastes. During the production of defense materials and while these wastes were stored in high-level waste tanks at the Hanford Site, some of these wastes were likely mixed with other waste constituents and materials. Recently, Pacific Northwest Laboratory (PNL) was commissioned by Westinghouse Hanford Company (WHC) to investigate the chemical reactivity of these ferrocyanide-bearing wastes. Because of known or potential thermal reactivity hazards associated with ferrocyanide- and nitrate-bearing wastes, and because of the potential for different materials to act as catalysts or initiators of the reactions about which there is concern, we at PNL have begun investigating the effects of the other potential waste constituents. This report presents the results of a preliminary screening study to identify classes of materials that might be in the Hanford high-level waste tanks and that could accelerate or reduce the starting temperature of the reaction(s) of concern. We plan to use the resulted of this study to determine which materials or class of materials merit additional research.
Date: May 1, 1992
Creator: Scheele, R. D.; Bryan, S. A.; Johnston, J. W.; Tingey, J. M.; Burger, L. L. & Hallen, R. T.
System: The UNT Digital Library