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Amplitude path corrections for regional phases in China
The authors investigate the effectiveness of amplitude path corrections for regional phases on seismic event discrimination and magnitude estimation. Waveform data from digital stations in China for regional, shallow (< 50 km) events were obtained from the IRIS Data Management Center (DMC) for years 1986 to 1996 using the USGS Preliminary Determination of Epicenters (PDE) and the Chinese State Seismological Bureau (SSB) catalogs. For each event, the amplitudes for each regional phase (P{sub n}, P{sub g}, S{sub n}, L{sub g}) were measured, as well as the P{sub g} and L{sub g} coda. Measured amplitudes were corrected for source scaling using estimates of m{sub b} and for distance using a power law that accounts for attenuation and spreading. The amplitude residuals were interpolated and mapped as 2-D amplitude correction surfaces. The authors employ several methods to create the amplitude correction surfaces: a waveguide method, and two interpolation methods (Baysian kriging and a circular moving window mean smoother). They explore the sensitivities of the surfaces to the method and to regional propagation, and apply these surfaces to correct amplitude data to reduce scatter in discrimination ratios and magnitude estimates.
Date:
December 31, 1998
Creator:
Phillips, W. S.; Velasco, A. A.; Taylor, S. R. & Randall, G. E.
Object Type:
Article
System:
The UNT Digital Library
Analysis and visualization of global magnetospheric processes
This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The purpose of this project is to develop new computational and visualization tools to analyze particle dynamics in the Earth`s magnetosphere. These tools allow the construction of a global picture of particle fluxes, which requires only a small number of in situ spacecraft measurements as input parameters. The methods developed in this project have led to a better understanding of particle dynamics in the Earth`s magnetotail in the presence of turbulent wave fields. They have also been used to demonstrate how large electromagnetic pulses in the solar wind can interact with the magnetosphere to increase the population of energetic particles and even form new radiation belts.
Date:
December 31, 1998
Creator:
Winske, D.; Mozer, F.S. & Roth, I.
Object Type:
Report
System:
The UNT Digital Library
Analysis of monthly mean cloud amount for China: 1951--1994
The distribution of clouds over the globe greatly influences the regimes of other important climatic variables, such as temperature and precipitation. While satellite records of cloudiness are extremely valuable in the study of the earth`s climate (spanning now 2--3 decades), the longer records of surface-observed cloudiness for much of the earth`s surface are preferred for integration with long-term records of other surface variables in attempting to understand these variables` relationships and trends. As databases of surface-based cloud observations have become available for research use over recent decades, there have been many studies concerned with examining trends in regional cloud cover. Kaiser and Vose (1997) performed a gridded analysis of variations and trends in cloud amount using 187 Chinese weather stations for the period 1954--1990. The main findings were significant decreases in annual mean cloud amount over much of northern China, coupled with corresponding increases in the frequency of occurrence of clear skies. The decreased trends in annual mean cloud amount over northern China were found to be driven by decreasing cloud amount over most months of the year. The current study uses an expanded period of record of China cloud observations (1951--1994) to re-examine trends in cloud amount at individuals …
Date:
December 31, 1998
Creator:
Kaiser, D. P.
Object Type:
Report
System:
The UNT Digital Library
Analysis of thermal issues associated with the pre-amplifier modules in the National Ignition Facility
The design of the National Ignition Facility (NIF) calls for a desired temperature field of 20.00 {+-} 0.28 C throughout the facility. This design requirement is needed to prevent degradation of the operating performance and net yield of the NIF by heat loads generated within the facility. In particular, the potential interference of waste heat from the lighting fixtures and equipment such as the electronics racks, and pre-amplifier modules (PAMs), and its impact on the operational performance of the laser beam transport tubes and optical alignment components must be evaluated. This report describes the thermal analyses associated with the PAMs. Evaluation of thermal issues for the other equipment is discussed elsewhere.
Date:
December 31, 1998
Creator:
Lam, K.L.
Object Type:
Report
System:
The UNT Digital Library
[Analysis of Trace Elements in Limestone for Archeological Functions]
Numerous quarries in the Lutetian limestone formations of the Paris Basin provided stone for the building and the decoration of monuments from antiquity to the present. To determine the origin of stone used for masonry and sculptures in these monuments, a team of geologists and archaeologists has investigated 300 quarries and collected 2,300 samples. Petrographic and paleontologic examination of thin sections allows geologists to distinguish Lutetian limestones from Jurassic and Cretaceous limestones. Geologists also seek to formulate hypotheses regarding the origin of Lutetian limestones used for building and sculpture in the Paris region. In the search for the sources of building and sculptural stone, the analytical methods of geologists are limited because often several quarries produce the same lithofacies. A new tool is now available, however, to attack questions of provenance raised by art historians. Because limestones from different sources have distinctive patterns of trace-element concentrations, compositional analysis by neutron activation allows one to compare building or sculptural stone from one monument with stone from quarries or other monuments. This analytical method subjects a powdered limestone sample to standard neutron activation analysis procedures at Brookhaven National Laboratory. With the help of computer programs, the compositional fingerprints of Lutetian limestones can …
Date:
December 31, 1998
Creator:
Blanc, A.; Holmes, L. & Harbottle, G.
Object Type:
Article
System:
The UNT Digital Library
Analysis of vibration and pressure pulsation in positive displacement drilling motors
Three, Moineau principle, positive displacement (drilling) motors were tested on a dynamometer using water, air/mist, and foam. In conjunction with a traditional motor performance test, data were collected at 5000 samples per second using an adapted seismic data acquisition system. Shaft speed, torque, pressure, and three-axis vibration data were processed using Seismic Analysis Code (SAC) to obtain energy density spectrums (EDSs). Cascade plots were generated by plotting the EDSs against shaft speed. The cascade plots revealed that pressure pulses and motor vibrations are closely related to the eccentric rotation of the rotor in the power section. Excessive no-load vibrations were not observed in the small motors and test apparatus used; increasing torque usually decreases the amplitude of vibrations observed. Motor vibration amplitudes were as a rule not increased when compressible fluids were substituted for water.
Date:
December 31, 1998
Creator:
Hamlin, D. B. & Dreesen, D. S.
Object Type:
Article
System:
The UNT Digital Library
Analysis, scientific computing and fundamental studies in fluid mechanics. Final report Number 21, May 1, 1997--September 30, 1998
This report is a summary of work in progress and completed. Subject areas covered are: effective numerical methods for interfacial flows; multiscale finite element methods: analysis and applications; an efficient boundary integral method for the Mullins-Sekera problem; numerical simulation of three-dimensional water waves using a fast summation method; numerical solutions of steady-state rising bubbles; solidification coupled to fluid convection; turbulence models; exact solution of very viscous and Hele-Shaw flow; fundamental vortex dynamics; functional methods for turbulence; structure functions for isotropic turbulence; and water waves.
Date:
December 31, 1998
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Annual symposium on Frontiers in Science
This final report summarizes activities conducted for the National Academy of Sciences' Annual Symposium on Frontiers of Science with support from the US Department of Energy for the period July 1, 1993 through May 31, 1998. During the report period, five Frontiers of Science symposia were held at the Arnold and Mabel Beckman Center of the National Academies of Sciences and Engineering. For each Symposium, an organizing committee appointed by the NAS President selected and planned the eight sessions for the Symposium and identified general participants for invitation by the NAS President. These Symposia accomplished their goal of bringing together outstanding younger (age 45 or less) scientists to hear presentations in disciplines outside their own and to discuss exciting advances and opportunities in their fields in a format that encourages, and allows adequate time for, informal one-on-one discussions among participants. Of the 458 younger scientists who participated, over a quarter (124) were women. Participant lists for all symposia (1993--1997) are attached. The scientific participants were leaders in basic research from academic, industrial, and federal laboratories in such disciplines as astronomy, astrophysics, atmospheric science, biochemistry, cell biology, chemistry, computer science, earth sciences, engineering, genetics, material sciences, mathematics, microbiology, neuroscience, physics, and …
Date:
December 31, 1998
Creator:
Metzger, N. & Fulton, K.R.
Object Type:
Report
System:
The UNT Digital Library
Application of molten salt oxidation for the minimization and recovery of plutonium-238 contaminated wastes
This paper presents the technical and economic feasibility of molten salt oxidation technology as a volume reduction and recovery process for {sup 238}Pu contaminated waste. Combustible low-level waste material contaminated with {sup 238}Pu residue is destroyed by oxidation in a 900 C molten salt reaction vessel. The combustible waste is destroyed creating carbon dioxide and steam and a small amount of ash and insoluble {sup 2328}Pu in the spent salt. The valuable {sup 238}Pu is recycled using aqueous recovery techniques. Experimental test results for this technology indicate a plutonium recovery efficiency of 99%. Molten salt oxidation stabilizes the waste converting it to a non-combustible waste. Thus installation and use of molten salt oxidation technology will substantially reduce the volume of {sup 238}Pu contaminated waste. Cost-effectiveness evaluations of molten salt oxidation indicate a significant cost savings when compared to the present plans to package, or re-package, certify and transport these wastes to the Waste Isolation Pilot Plant for permanent disposal. Clear and distinct cost advantages exist for MSO when the monetary value of the recovered {sup 238}Pu is considered.
Date:
December 31, 1998
Creator:
Wishau, R.; Ramsey, K.B. & Montoya, A.
Object Type:
Article
System:
The UNT Digital Library
Application of new techniques for EOS data
This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). One area of great uncertainty as well as high physics leverage is that of the material properties of plutonium and other materials including zirconium, uranium-niobium, deuterium-tritium, tantalum, beryllium, and oralloy. These properties include plutonium Hugoniot and melt-curve data to 10 Mbars and the plutonium off-Hugoniot data. Their goal is a proof-of-principle experiment on the Los Alamos Trident laser that will determine the technical and logistical issues involved with performing an accurate equation-of-state (EOS) and melt-curve experiment with plutonium, as well as performing initial measurements on the plutonium Hugoniot. This method can also be used to gather data at relatively low cost for other materials as well. Such a capability would complement existing gas-gun facilities and laser-driven miniflyers.
Date:
December 31, 1998
Creator:
Hsing, W.
Object Type:
Report
System:
The UNT Digital Library
Application of X-ray K-edge densitometry in D and D operations
K-edge densitometry is a nondestructive assay technique which provides accurate measurement of heavy metal contamination in pipes, containers, and other items encountered in D and D operations. A prototype mobile K-edge instrument has been built and demonstrated in several applications. Results from measurements of uranium in pipes and spent reactor fuel plates, and quantification of mercury and lead in waste drums are presented. In this report the authors briefly describe the theory behind K-edge densitometry. They follow that with a description of the prototype system they have developed, and a presentation of results from demonstrations of this system. They conclude with a discussion of the potential for application of K-edge analysis in D and D operations.
Date:
December 31, 1998
Creator:
Jensen, T.; Aljundi, T. & Gray, J.N.
Object Type:
Article
System:
The UNT Digital Library
Applications of dielectric barrier discharges
Dielectric barrier discharges (DBDs) in oxygen and air are well established for the production of large quantities of ozone and are more recently being applied to a wider range of plasmachemical processes. Here, the application of DBDs for ozone synthesis, the non-thermal oxidation of volatile organic compounds (VOCs) in air, the generation of incoherent (V)UV radiation and surface processing (etching, ashing) is presented. The main plasmaphysical features of sinusoidally-driven DBDs (transient, filamented, non-thermal plasmas at atmospheric pressure) are described, and a simple plasmachemical reaction pathway for ozone synthesis are give. Experimental results on the degradation of VOCs (2-propanol, trichloroethylene, carbon tetrachloride), as well as byproduct formation is presented for stand-alone DBD treatment, as well as for simultaneous (V)UV illumination of the discharge. Illumination of the discharge with (V)UV can change the plasmachemistry by enhanced formation of certain species of radicals--and thereby change byproduct formation--but also can change the discharge physics, known as the Joshi effect. As an example for generation of excited dimers and exiplexes for the production of incoherent UV light, experimental results on a XeBr* excimer UV light source are presented. Effects of the total and partial pressure of a Xe/Br{sub 2} system, the gap spacing and the …
Date:
December 31, 1998
Creator:
Falkenstein, Z.
Object Type:
Article
System:
The UNT Digital Library
Applications of inventory difference tool at Los Alamos Plutonium Facility
A prototype computer program reads the inventory entries directly from the Microsoft Access database. Based on historical data, the program then displays temporal trends and constructs a library of rules that encapsulate the system behavior. The analysis of inventory data is illustrated using a combination of realistic and simulated facility examples. Potential payoffs of this methodology include a reduction in time and resources needed to perform statistical tests and a broad applicability to DOE needs such as treaty verification.
Date:
December 31, 1998
Creator:
Hench, K.W.; Longmire, V.; Yarbro, T.F. & Zardecki, A.
Object Type:
Article
System:
The UNT Digital Library
Archer County News (Archer City, Tex.), No. 53, Ed. 1 Thursday, December 31, 1998
Weekly newspaper from Archer City, Texas that includes local, state and national news along with advertising.
Date:
December 31, 1998
Creator:
Lewis, Shelley
Object Type:
Newspaper
System:
The Portal to Texas History
Architectural design criteria for f-block metal ion sequestering agents. 1998 annual progress report
'The objective of this project is to provide a means to optimize ligand architecture for f-block metal recognition. The authors strategy builds on an innovative and successful molecular modeling approach in developing polyether ligand design criteria for the alkali and alkaline earth cations. The hypothesis underlying this proposal is that differences in metal ion binding with multidentate ligands bearing the same number and type of donor groups are primarily attributable to intramolecular steric factors. They propose quantifying these steric factors through the application of molecular mechanics models. The research involves close integration of theoretical and experimental chemistry. The experimental work entails synthesizing novel ligands and experimentally determining structures and binding constants for metal ion complexation by series of ligands in which architecture is systematically varied. The theoretical work entails using electronic structure calculations to parameterize a molecular mechanics force field for a range of metal ions and ligand types. The resulting molecular mechanics force field will be used to predict low energy structures for unidentate, bidentate, and multidentate ligands and their metal complexes through conformational searches. Results will be analyzed to assess the relative importance of several steric factors including optimal M-L length, optimal geometry at the metal center, optimal …
Date:
December 31, 1998
Creator:
Hay, Benjamin P.; Dixon, David A.; Roundhill, D. Max; Rogers, Robin D.; Paine, Robert T. & Raymond, Kenneth N.
Object Type:
Report
System:
The UNT Digital Library
D-area oil seepage basin bioventing optimization test plan
The D Area Oil Seepage Basin (DOSB) was used from 1952 to 1975 for disposal of petroleum-based products (waste oils), general office and cafeteria waste, and apparently some solvents [trichloroethylene (TCE)/tetrachloroethylene (PCE)]. Numerous analytical results have indicated the presence of TCE and its degradation product vinyl chloride in groundwater in and around the unit, and of petroleum hydrocarbons in soils within the unit. The DOSB is slated for additional assessment and perhaps for environmental remediation. In situ bioremediation represents a technology of demonstrated effectiveness in the reclamation of sites contaminated with petroleum hydrocarbons and chlorinated solvents, and has been retained as an alternative for the cleanup of the DOSB. The Savannah River Site is therefore proposing to conduct a field treatability study designed to demonstrate and optimize the effectiveness of in situ microbiological biodegradative processes at the DOSB. The introduction of air and gaseous nutrients via two horizontal injection wells (bioventing) is expected to enhance biodegradation rates of petroleum components and stimulate microbial degradation of chlorinated solvents. The data gathered in this test will allow a determination of the biodegradation rates of contaminants of concern in the soil and groundwater, allow an evaluation of the feasibility of in situ bioremediation …
Date:
December 31, 1998
Creator:
Berry, C.J.; Radway, J.C.; Alman, D. & Hazen, T.C.
Object Type:
Report
System:
The UNT Digital Library
The ARM eddy correlation system for monitoring surface fluxes
The Atmospheric Radiation Measurement (ARM) Program was established by the Department of Energy as part of the US Global Climate Change Research Program to improve methods of determining radiative transfer and cloud processes in large-scale models. The ARM observational facility in the Southern Great Plains (SGP) of the US uses various types of instrument systems to make continuous measurements of the state of the atmosphere, cloud properties, radiative transfer, and other forms of energy transfer. Most of the instrument systems for these continuous observations come from commercial sources; many are adaptations of systems that have been used previously, mostly in short-term field campaigns. Eddy correlation systems (ECORs) are used to measure the air-surface exchange rates of heat, moisture, and momentum at eight locations in the overall area (350 km by 400 km) of the SGP site. At most locations, measurements are made at a height of about three meters above the ground over tilled agricultural land. At 14 other locations, air-surface exchange is measured above grasslands with an energy balance Bowen ratio system.
Date:
December 31, 1998
Creator:
Hart, R.L.; Cook, D.R. & Wesely, M.L.
Object Type:
Article
System:
The UNT Digital Library
Array design and expression evaluation in POOMA II
POOMA is a templated C++ class library for use in the development of large-scale scientific simulations on serial and parallel computers. POOMA II is a new design and implementation of POOMA intended to add richer capabilities and greater flexibility to the framework. The new design employs a generic Array class that acts as an interface to, or view on, a wide variety of data representation objects referred to as engines. This design separates the interface and the representation of multidimensional arrays. The separation is achieved using compile-time techniques rather than virtual functions, and thus code efficiency is maintained. POOMA II uses PETE, the Portable Expression Template Engine, to efficiently represent complex mathematical expressions involving arrays and other objects. The representation of expressions is kept separate from expression evaluation, allowing the use of multiple evaluator mechanisms that can support nested where-block constructs, hardware-specific optimizations and different run-time environments.
Date:
December 31, 1998
Creator:
Karmesin, S.; Crotinger, J.; Cummings, J.; Haney, S.; Humphrey, W.; Reynders, J. et al.
Object Type:
Article
System:
The UNT Digital Library
Artificial neural network simulation of battery performance
Although they appear deceptively simple, batteries embody a complex set of interacting physical and chemical processes. While the discrete engineering characteristics of a battery such as the physical dimensions of the individual components, are relatively straightforward to define explicitly, their myriad chemical and physical processes, including interactions, are much more difficult to accurately represent. Within this category are the diffusive and solubility characteristics of individual species, reaction kinetics and mechanisms of primary chemical species as well as intermediates, and growth and morphology characteristics of reaction products as influenced by environmental and operational use profiles. For this reason, development of analytical models that can consistently predict the performance of a battery has only been partially successful, even though significant resources have been applied to this problem. As an alternative approach, the authors have begun development of a non-phenomenological model for battery systems based on artificial neural networks. Both recurrent and non-recurrent forms of these networks have been successfully used to develop accurate representations of battery behavior. The connectionist normalized linear spline (CMLS) network has been implemented with a self-organizing layer to model a battery system with the generalized radial basis function net. Concurrently, efforts are under way to use the feedforward …
Date:
December 31, 1998
Creator:
O`Gorman, C. C.; Ingersoll, D.; Jungst, R. G. & Paez, T. L.
Object Type:
Article
System:
The UNT Digital Library
Assessing the potential of bioenergy. Final report, October 1, 1997--September 30, 1998
As electricity restructuring proceeds, traditional concepts of how energy is produced, transported, and utilized are likely to change dramatically. Marketplace, policy, and regulatory changes will shape both the domestic and global energy industry, improving opportunities for clean, low-cost energy, competitively priced fuels, and environmentally responsible power systems. Many of these benefits may be obtained by commercial deployment of advanced biomass power conversion technologies. The United BioEnergy Commercialization Association represents the US biomass power industry. Its membership includes investor-owned and public utilities, independent power producers, state and regional bioenergy, equipment manufacturers, and biomass energy developers. To carry out its mission, UBECA has been carrying out the following activities: production of informational and educational materials on biomass energy and distribution of such materials at public forums; technical and market analyses of biomass energy fuels, conversion technologies, and market issues; monitoring of issues affecting the biomass energy community; and facilitating cooperation among members to leverage the funds available for biomass commercialization activities.
Date:
December 31, 1998
Creator:
Kirschner, J. & Badin, J.
Object Type:
Report
System:
The UNT Digital Library
Assessment of capital requirements for alternative fuels infrastructure under the PNGV program
This paper presents an assessment of the capital requirements of using six different fuels in the vehicles with tripled fuel economy (3X vehicles) that the Partnership for a new Generation of Vehicles is currently investigating. The six fuels include two petroleum-based fuels (reformulated gasoline and low-sulfur diesel) and four alternative fuels (methanol, ethanol, dimethyl ether, and hydrogen). This study develops estimates of cumulative capital needs for establishing fuels production and distribution infrastructure to accommodate 3X vehicle fuel needs. Two levels of fuel volume-70,000 barrels per day and 1.6 million barrels per day-were established for meeting 3X-vehicle fuel demand. As expected, infrastructure capital needs for the high fuel demand level are much higher than for the low fuel demand level. Between fuel production infrastructure and distribution infrastructure, capital needs for the former far exceed those for the latter. Among the four alternative fuels, hydrogen bears the largest capital needs for production and distribution infrastructure.
Date:
December 31, 1998
Creator:
Stork, K.; Singh, M.; Wang, M. & Vyas, A.
Object Type:
Article
System:
The UNT Digital Library
Assessment of cold neutron radiography capability
This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors goals were to demonstrate and assess cold neutron radiography techniques at the Los Alamos Neutron Science Center (LANSCE), Manual Lujan Neutron Scattering Center (Lujan Center), and to investigate potential applications of the capability. The authors have obtained images using film and an amorphous silicon detector. In addition, a new technique they have developed allows neutron radiographs to be made using only a narrow range of neutron energies. Employing this approach and the Bragg cut-off phenomena in certain materials, they have demonstrated material discrimination in radiography. They also demonstrated the imaging of cracks in a sample of a fire-set case that was supplied by Sandia National Laboratory, and they investigated whether the capability could be used to determine the extent of coking in jet engine nozzles. The LANSCE neutron radiography capability appears to have applications in the DOE stockpile maintenance and science-based stockpile stewardship (SBSS) programs, and in industry.
Date:
December 31, 1998
Creator:
McDonald, Thomas E., Jr. & Roberts, Joyce A.
Object Type:
Report
System:
The UNT Digital Library
Asymmetry in inclusive {pi}{sup {+-}}, p production at 22 GeV, BNL E925
Preliminary results from Experiment E925 on inclusive pion asymmetries from a 22 GeV/c polarized proton beam on a carbon target show significant asymmetries for {pi}{sup {+-}} production similar to those observed earlier at the ZGS and Fermilab with beams of 12 and 200 GeV respectively. This experiment demonstrates the viability of using the analyzing power in inclusive pion production for high energy beam polarimetry at RHIC. Inclusive proton asymmetries are consistent with zero.
Date:
December 31, 1998
Creator:
Makdisi, Y.; Allgower, C. & Bai, M.
Object Type:
Article
System:
The UNT Digital Library
Base Distance Optimization for SQUID Gradiometers
The measurement of magnetic fields generated by weak nearby biomagnetic sources is affected by ambient noise generated by distant sources both internal and external to the subject under study. External ambient noise results from sources with numerous origins, many of which are unpredictable in nature. Internal noise sources are biomagnetic in nature and result from muscle activity (such as the heart, eye blinks, respiration, etc.), pulsation associated with blood flow, surgical implants, etc. Any magnetic noise will interfere with measurements of magnetic sources of interest, such as magnetoencephalography (MEG), in various ways. One of the most effective methods of reducing the magnetic noise measured by the SQUID sensor is to use properly designed superconducting gradiometers. Here, the authors optimized the baseline length of SQUID-based symmetric axial gradiometers using computer simulation. The signal-to-noise ratio (SNR) was used as the optimization criteria. They found that in most cases the optimal baseline is not equal to the depth of the primary source, rather it has a more complex dependence on the gradiometer balance and the ambient magnetic noise. They studied both first and second order gradiometers in simulated shielded environments and only second order gradiometers in a simulated unshielded environment. The noise source …
Date:
December 31, 1998
Creator:
Garachtchenko, Alexander; Matlashov, Andrei & Kraus, Robert
Object Type:
Article
System:
The UNT Digital Library