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Location Algorithms and Errors in Time-of-Arrival Systems
This report describes least squares solution methods and linearized estimates of solution errors caused by data errors. These methods are applied to event locating systems which use time-of-arrival (TOA) data. Analyses are presented for algorithms that use the TOA data in a ''direct'' manner and for algorithms utilizing Time-of-arrival Squared (TSQ) methods. Location and error estimation results were applied to a ''typical'' satellite TOA detecting system. Using Monte Carlo methods, it was found that the linearized location error estimates were valid for random data errors with relatively large variances and relatively poor event/sensor geometries. In addition to least squares methods, which use an L{sub 2} norm, methods were described for L{sub 1} and L{sub {infinity}} norms. In general, these latter norms offered little improvement over least squares methods. Reduction of the location error variances can be effected by using information in addition to the TOA data themselves by adding judiciously chosen ''conditioning'' equation(s) to the least squares system. However, the added information can adversely affect the mean errors. Also, conditioned systems may offer location solutions where nonconditioned scenarios may not be solvable. Solution methods and linearized error estimates are given for ''conditioned'' systems. It was found that for significant data …
Date:
September 1, 2001
Creator:
AARONSON, EUGENE A.
Object Type:
Report
System:
The UNT Digital Library
Environmental Sampling FY01 Annual Report - Understanding the Movement of Mercury in the Environmental Surrounding the INEEL
Environmental fate and transport of the toxic air pollutant mercury (Hg) is currently a high-priority regional concern for the INEEL, and national and global concern for the U.S. Environmental Protection Agency (EPA). At the INEEL’s Idaho Nuclear Technology and Engineering Center (INTEC), significant quantities (est. 40 kg/year) of Hg may have been released over 37 years of Environmental Management’s (EM) High-Level Waste (HLW) treatment operations. The EPA is very concerned about the continued global buildup of Hg in the atmosphere and aquatic ecosystems, and has recently invested heavily in Hg research to better understand its complex environmental cycling.1,2 The Environmental Sampling work began in FY99 as a joint INEEL/U.S. Geological Survey (USGS) field research effort to (a) better understand the fate and potential impacts of Hg emissions from the INEEL’s HLW treatment operations (operational component) and (b) contribute at a national level to the scientific understanding of local, regional, and global Hg fate and transport (research component). The USGS contributed snow sampling support in the field (Water Resources Division, Salt Lake City) and laboratory analysis of all samples (Wisconsin District Mercury Research Laboratory).
Date:
September 1, 2001
Creator:
Abbott, Michael Lehman
Object Type:
Report
System:
The UNT Digital Library
The Framework for Approximate Queries on Simulation Data
AQSim is a system intended to enable scientists to query and analyze a large volume of scientific simulation data. The system uses the state of the art in approximate query processing techniques to build a novel framework for progressive data analysis. These techniques are used to define a multi-resolution index, where each node contains multiple models of the data. The benefits of these models are two-fold: (1) they are compact representations, reconstructing only the information relevant to the analysis, and (2) the variety of models capture different aspects of the data which may be of interest to the user but are not readily apparent in their raw form. To be able to deal with the data interactively, AQSim allows the scientist to make an informed tradeoff between query response accuracy and time. In this paper, we present the framework of AQSim with a focus on its architectural design. We also show the results from an initial proof-of-concept prototype developed at LLNL. The presented framework is generic enough to handle more than just simulation data.
Date:
September 27, 2001
Creator:
Abdulla, G.; Baldwin, C.; Critchlow, T.; Kamimura, R.; Lee, B.; Musick, R. et al.
Object Type:
Article
System:
The UNT Digital Library
Electricity: The Road Toward Restructuring
The Public Utility Holding Company Act of 1935 (PUHCA) and the Federal Power Act (FPA) were enacted to eliminate unfair practices and other abuses by electricity and gas holding companies by requiring federal control and regulation of interstate public utility holding companies. Comprehensive energy legislation has passed the House and Senate. The House passed H.R. 6 on April 11, 2003. On July 31, 2003, the Senate suspended debate on S. 14, inserted the text of H.R. 4 (107th Congress) as a substitute, and passed H.R. 6. A conference agreement was reached November 17, 2003, and passed by the House the next day. H.R. 6 includes an electricity title that would, in part, repeal PUHCA, would prospectively repeal the mandatory purchase requirement under PURPA, and would create an electric reliability organization. On June 15, 2004, H.R. 4503, a comprehensive energy policy bill, passed the House.
Date:
September 7, 2001
Creator:
Abel, Amy & Parker, Larry
Object Type:
Report
System:
The UNT Digital Library
Abilene Philharmonic Playbill: September 15-October 27, 2001
Program for an Abilene Philharmonic concert that ran from September 15th to October 27th (classical concert) during the 51st season. It includes information about the pieces performed, artists and musicians, and advertising from local companies.
Date:
September 2001
Creator:
Abilene Philharmonic
Object Type:
Book
System:
The Portal to Texas History
Response to Terrorism: Legal Aspects of the Use of Military Force
None
Date:
September 13, 2001
Creator:
Ackerman, David M.
Object Type:
Report
System:
The UNT Digital Library
Development of Attrition Resistant Iron-Based Fischer-Tropsch Catalysts
The Fischer-Tropsch (F-T) reaction provides a way of converting coal-derived synthesis gas (CO+H{sub 2}) to liquid fuels. Since the reaction is highly exothermic, one of the major problems in control of the reaction is heat removal. Recent work has shown that the use of slurry bubble column reactors (SBCRs) can largely solve this problem. The use of iron-based catalysts is attractive not only due to their low cost and ready availability, but also due to their high water-gas shift activity which makes it possible to use these catalysts with low H{sub 2}/CO ratios. However, a serious problem with use of Fe catalysts in a SBCR is their tendency to undergo attrition. This can cause fouling/plugging of downstream filters and equipment, makes the separation of catalyst from the oil/wax product very difficult if not impossible, and results in a steady loss of catalyst from the reactor. Recently, fundamental understanding of physical attrition is being addressed by incorporating suitable binders into the catalyst recipe. This has resulted in the preparation of a spray dried Fe-based catalyst having aps of 70 mm with high attrition resistance. This Fe-based attrition resistant, active and selective catalyst gave 95% CO conversion through 125 hours of testing …
Date:
September 1, 2001
Creator:
Adeyiga, Adeyinka A.
Object Type:
Report
System:
The UNT Digital Library
RF Gas Plasma Source Development for Heavy Ion Fusion
Presently the Heavy Ion Fusion Virtual National Laboratory is researching ion sources and injector concepts to understand how to optimize beam brightness over a range of currents (50-2000 mA argon equivalent). One concept initially accelerates millimeter size, milliamp beamlets to 1 MeV before merging them into centimeter size, ampere beams. Computer simulations have shown the final brightness of the merged beams is dominated by the emittance growth of the merging process, as long as the beamlets ion temperature is below a few eV. Thus, a RF multicusp source capable of high current density can produce beams with better brightness compared to ones extracted from a colder source with a large aperture and lower current density. As such, experiments have begun to develop a RF multicusp source capable of delivering one amp of extracted beam current. It is expected that it will require 10 kW of 13 MHz RF power delivered via a quartz shielded, one and half turn, four inch diameter antenna. Important considerations in the development of the source include the dependence of current density and beam ion temperature on consumed RF power and gas pressure. A fast rise time ({approx} 100 ns) for the extracted beam pulse must …
Date:
September 4, 2001
Creator:
Ahle, L.; Hall, R. P.; Molvik, A. W.; Kwan, J. W. & Leung, K. N.
Object Type:
Article
System:
The UNT Digital Library
Neutrino Observations From the Sudbury Neutrino Observatory
The Sudbury Neutrino Observatory (SNO) is a water imaging Cherenkov detector. Its usage of 1000 metric tons of D{sub 2}O as target allows the SNO detector to make a solar-model independent test of the neutrino oscillation hypothesis by simultaneously measuring the solar {nu}{sub e} flux and the total flux of all active neutrino species. Solar neutrinos from the decay of {sup 8}B have been detected at SNO by the charged-current (CC) interaction on the deuteron and by the elastic scattering (ES) of electrons. While the CC reaction is sensitive exclusively to {nu}{sub e}, the ES reaction also has a small sensitivity to {nu}{sub {mu}} and {nu}{sub {tau}}. In this paper, recent solar neutrino results from the SNO experiment are presented. It is demonstrated that the solar flux from {sup 8}B decay as measured from the ES reaction rate under the no-oscillation assumption is consistent with the high precision ES measurement by the Super-Kamiokande experiment. The {nu}{sub e} flux deduced from the CC reaction rate in SNO differs from the Super-Kamiokande ES results by 3.3{sigma}. This is evidence for an active neutrino component, in additional to {nu}{sub e}, in the solar neutrino flux. These results also allow the first experimental determination …
Date:
September 24, 2001
Creator:
Ahmad, Q. R.; Allen, R. C.; Andersen, T. C.; Anglin, J. D.; Barton, J. C.; Beier, E. W. et al.
Object Type:
Article
System:
The UNT Digital Library
Development of Improved Catalysts for the Selective Catalytic Reduction of Nitrogen Oxides with Hydrocarbons
Significant work has been done by the investigators on the cerium oxide-copper oxide based sorbent/catalysts for the combined removal of sulfur and nitrogen oxides from the flue gases of stationary sources. A relatively wide temperature window was established for the use of alumina-supported cerium oxide-copper oxide mixtures as regenerable sorbents for SO{sub 2} removal. Preliminary evaluation of these sorbents as catalysts for the selective reduction of NO{sub x} gave promising results with ammonia, but indicated low selectivity when methane was used as the reductant. Since the replacement of ammonia by another reductant is commercially very attractive, in this project, four research components will be undertaken. The investigation of the reaction mechanism, the first component, will help in the selection of promoters to improve the catalytic activity and selectivity of the sorbents in the SCR with methane. This will result in new catalyst formulations (second component). If this research is successful, the combined SO{sub 2}-NO{sub x} removal process based on alumina-supported copper oxide-ceria sorbent/catalysts will become very attractive for commercial applications. The objective of the third component of the project is to develop an alternative SCR process using another inexpensive fuel, residual fuel oil, instead of natural gas. This innovative proposal …
Date:
September 1, 2001
Creator:
Akyurtlu, Ates & Akyurtlu, Jale F.
Object Type:
Report
System:
The UNT Digital Library
AUTOMATION FOR THE SYNTHESIS AND APPLICATION OF PET RADIOPHARMACEUTICALS.
The development of automated systems supporting the production and application of PET radiopharmaceuticals has been an important focus of researchers since the first successes of using carbon-11 (Comar et al., 1979) and fluorine-18 (Reivich et al., 1979) labeled compounds to visualize functional activity of the human brain. These initial successes of imaging the human brain soon led to applications in the human heart (Schelbert et al., 1980), and quickly radiochemists began to see the importance of automation to support PET studies in humans (Lambrecht, 1982; Langstrom et al., 1983). Driven by the necessity of controlling processes emanating high fluxes of 511 KeV photons, and by the tedium of repetitive syntheses for carrying out these human PET investigations, academic and government scientists have designed, developed and tested many useful and novel automated systems in the past twenty years. These systems, originally designed primarily by radiochemists, not only carry out effectively the tasks they were designed for, but also demonstrate significant engineering innovation in the field of laboratory automation.
Date:
September 21, 2001
Creator:
Alexoff, D. L.
Object Type:
Book
System:
The UNT Digital Library
Columbia River Wildlife Habitat Evaluation Procedures Report For The Bliss, Burlington Northern, James, and Straub Tracts Of The Stiegerwald Lake National Wildlife Refuge
Steigenvald Lake National Wildlife Refuge (NWR, refuge) was established as a result of the U. S. Army Corps of Engineers (COE) transferring ownership of the Stevenson tract located in the historic Steigerwald Lake site to the U.S. Fish and Wildlife Service (FWS, Service) for the mitigation of the fish and wildlife losses associated with the construction of a second powerhouse at the Bonneville Dam on the Columbia River and relocation of the town of North Bonneville (Public Law 98-396). The construction project was completed in 1983 and resulted in the loss of approximately 577 acres of habitat on the Washington shore of the Columbia River (USFWS, 1982). The COE determined that acquisition and development of the Steigenvald Lake area, along with other on-site project management actions, would meet their legal obligation to mitigate for these impacts (USCOE, 1985). Mitigation requirements included restoration and enhancement of this property to increase overall habitat diversity and productivity. From 1994 to 1999, 317 acres of additional lands, consisting of four tracts of contiguous land, were added to the original refuge with Bonneville Power Administration (BPA) funds provided through the Washington Wildlife Mitigation Agreement. These tracts comprised Straub (191 acres), James (90 acres), Burlington Northern …
Date:
September 2001
Creator:
Allard, Donna
Object Type:
Report
System:
The UNT Digital Library
[Scarbrough Building Photograph #1]
Photograph of the Scarbrough Building, in Austin, Texas.
Date:
September 2001
Creator:
Allen, Phoebe
Object Type:
Photograph
System:
The Portal to Texas History
Oral History Interview with Robert Allender, September 23, 2001
The National Museum of the Pacific War presents an oral interview with Robert Allender. Allender was born in Oskaloosa, Iowa 21 November 1925 and enlisted in the Navy after graduating from high school in 1943. He qualified for sonar school while in boot camp and went to San Diego. Upon graduating from the school, he was sent to duty aboard the USS YMS-387, an auxiliary motor minesweeper. He describes his time on the YMS, engaged in coastal minesweeping and training prospective minesweeper crews. He left the minesweeper in December 1944 and was assigned to the commissioning crew of a coastal patrol craft in Portland, Oregon in the spring of 1945. He describes convoy duty between Pearl Harbor and the South Pacific, and operations near Eniwetok, Saipan, Guam and Ulithi. He recalls that following the Japanese surrender, his patrol craft was sent to Yap to accept the surrender of the Japanese garrison. The ship left Ulithi in November 1945 and returned to Charleston, South Carolina for decommissioning. He was discharged from the Navy in April 1946.
Date:
September 23, 2001
Creator:
Allender, Robert
Object Type:
Sound
System:
The Portal to Texas History
Oral History Interview with Robert Allender, September 23, 2001
The National Museum of the Pacific War presents an oral interview with Robert Allender. Allender was born in Oskaloosa, Iowa 21 November 1925 and enlisted in the Navy after graduating from high school in 1943. He qualified for sonar school while in boot camp and went to San Diego. Upon graduating from the school, he was sent to duty aboard the USS YMS-387, an auxiliary motor minesweeper. He describes his time on the YMS, engaged in coastal minesweeping and training prospective minesweeper crews. He left the minesweeper in December 1944 and was assigned to the commissioning crew of a coastal patrol craft in Portland, Oregon in the spring of 1945. He describes convoy duty between Pearl Harbor and the South Pacific, and operations near Eniwetok, Saipan, Guam and Ulithi. He recalls that following the Japanese surrender, his patrol craft was sent to Yap to accept the surrender of the Japanese garrison. The ship left Ulithi in November 1945 and returned to Charleston, South Carolina for decommissioning. He was discharged from the Navy in April 1946.
Date:
September 23, 2001
Creator:
Allender, Robert
Object Type:
Text
System:
The Portal to Texas History
Microchannel devices
The fabrication of stainless steel microchannel heat exchangers was examined through microlamination, the process of diffusion bonding precision machined metallic foils. The influence of diffusion bonding parameters, as well as the device geometry on the strength of the bond between the foils and embedded channel integrity, was investigated. During diffusion bonding, high temperatures and/or pressures result in well bonded foils, but these conditions cause the embedded channels to deform, which will degrade the efficiency of fluid flow through the channels. Alternatively, low temperatures and/or pressures result in undeformed channels but weakly bonded foils. This causes failure of the device due to fluid leakage. Thus, a processing envelope exists for producing a sound device with no fluid leakage and no degradation of fluid flow properties. The theoretical limit on aspect ratio within two-fluid counter-flow microchannel heat exchangers was also investigated. A counter-flow device is comprised of alternating layers of microchannels, which allow the two fluids to flow in opposite directions separated by fins. A theoretical model for interpreting the span of the fin as a function of the fin thickness was established. The model was verified experimentally by fabricating specimens to simulate the counter-flow device. The results of these investigations were …
Date:
September 1, 2001
Creator:
Alman, David E. & Wilson, Rick D.
Object Type:
Article
System:
The UNT Digital Library
Southwest Retort, Volume 54, Number 1, September 2001
This publication of the Dallas-Fort Worth Section of the American Chemical Society includes information about research, prominent scientist, organizational business, and various other stories of interest to the community.
Date:
September 2001
Creator:
American Chemical Society. Dallas/Fort Worth Section.
Object Type:
Journal/Magazine/Newsletter
System:
The UNT Digital Library
Three-Dimensional Position-Sensitive Germanium Detectors
Critical to the DOE effort to deactivate and decommission the weapons complex facilities is the characterization of contaminated equipment and building structures. This characterization includes the isotopic identification of radioactive contaminants and the spatial mapping of these deposits. The penetrating nature of the gamma rays emitted by the radioactive contaminants provides a means to accomplish this task in a passive, non-destructive and non-intrusive manner. Through conventional gamma-ray spectroscopy, the radioactive isotopes in the contaminants can be identified by their characteristic gamma-ray signatures and the amount of each isotope by the intensity of the signature emission. With the addition of gamma ray imaging, the spatial distributions of the isotopes can simultaneously be obtained. The ability to image radioactive contaminants can reduce waste as well as help ensure the adequate protection of workers and the environment. For example, if equipment and building materials have been subjected to radionuclide contamination, the entire structure must be treated as radioactive waste during demolition. However, only partial removal may be necessary if the contamination can be accurately located and identified. Hand-held survey instrumentation operated in the near vicinity of the contaminated objects is a common method to accomplish this task. This method necessitates long data acquisition …
Date:
September 30, 2001
Creator:
Amman, Mark & Luke, Paul
Object Type:
Report
System:
The UNT Digital Library
Amtrak Reform Council
Amtrak Reform Council (ARC) is an independent federal commission established under the Amtrak Reform and Accountability Act of 1997 (ARAA), which gave the Council a statutory mandate: (i) to recommend to Amtrak actions that the Corporation can take to improve its operational and financial performance; (ii) to monitor Amtrak's financial performance in the light of both Amtrak's own goals for financial performance, as established in its strategic business plan, and the statutory requirement that Amtrak be free of the need for operating grants after the fifth anniversary of the enactment of the ARAA; and (iii) should the Council find that Amtrak has not achieved or will not achieve either of its financial targets, then it is to forward to the Congress recommendations for a restructured and rationalized national intercity rail passenger system.
Date:
September 13, 2001
Creator:
Amtrak Reform Council
Object Type:
Website
System:
The UNT Digital Library
Design of surface texture for improved control of friction and formability of aluminum sheet products for automotive applications. Final technical report for period September 15, 1996 - July 14, 2000
The frictional properties of interfaces are of interest in a broad range of applications. We have formulated a new plasticity model for interface friction and applied it to represent the frictional characteristics of A16111-T4 sheet against D2 tool steel for sheet forming applications.
Date:
September 12, 2001
Creator:
Anand, L.
Object Type:
Report
System:
The UNT Digital Library
Atomic scale heating in energetic plasma deposition
Energetic deposition using filtered cathodic arc plasma is known to lead to well adherent and dense films. Interface mixing, subplantation depth, texture, and stress of the growing film are often studied as a function of the kinetic energy of condensing ions. Ions have also potential energy contributing to atomic scale heating, secondary electron emission and potential sputtering, thereby affecting all film properties. A table is presented showing kinetic and potential energies of ions in cathodic arc plasmas. These energies are greater than the binding energy, surface binding energy, and activation energy of surface diffusion. The role of potential energy on film growth is not limited to the cathodic arc plasma deposition process.
Date:
September 28, 2001
Creator:
Anders, Andre
Object Type:
Article
System:
The UNT Digital Library
Imaging the separation of cathodic arc plasma and macroparticles in curved magnetic filters
None
Date:
September 26, 2001
Creator:
Anders, Andre
Object Type:
Article
System:
The UNT Digital Library
LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES
This project has three main goals: Thin Films Studies, Preparation of Graded Porous Substrates and Basic Electrical Characterization and testing of Planar Single Cells. In this portion of study we have focused on producing YSZ films on porous LSM substrates. When using the polymer precursor there are a number of obstacles to overcome in order to form dense electrolyte layers on porous substrates (cathode or anode). Probably the most difficult problems are: (1) Extreme penetration of the polymer into the substrate must be prevented. (2) Shrinkage cracking must be avoided. (3) Film thickness in the 1 to 5{micro}m range must be achieved. We have demonstrated that cracking due to shrinkage involved during the elimination of solvents and organic matter and densification of the remaining oxide is not a problem as long as the resulting oxide film is < {approx} 0.15 {micro}m in thickness. We have also shown that we can make thicker films by making multiple depositions if the substrate is smooth (roughness {le} 0.1 {micro}m) and contains no surface pores > 0.2 {micro}m. The penetration of the polymer into the porous substrate can be minimized by increasing the viscosity of the polymer and reducing the largest pore at the …
Date:
September 30, 2001
Creator:
Anderson, Harlan U.; Huebner, Wayne & Kosacki, Igor
Object Type:
Report
System:
The UNT Digital Library
Unvented Attic Increases Energy Efficiency and Reduces Duct Losses - Sun Lake at Banning, California
New houses in the Sun Lakes at Banning subdivision are designed by Pulte Homes with technical support from the Building Science Consortium as part of the U.S. Department of Energy's Building America Program. These homes save their homeowners money by applying the principles of ''whole-building'' design, which considers the house as a complete system instead of separate components.
Date:
September 5, 2001
Creator:
Anderson, R. & Wells, N.
Object Type:
Book
System:
The UNT Digital Library