Simulating cometary and stellar x-ray emission in the laboratory using microcalorimeters and an electron beam ion trap (open access)

Simulating cometary and stellar x-ray emission in the laboratory using microcalorimeters and an electron beam ion trap

The mixing of atomic and macroscopic processes taking place in non-terrestrial objects creates complex, dynamic, and intriguing environments. High-resolution x-ray spectra from these sources measured by satellites such as Chandra, XMM-Newton, and the Solar Maximum Mission provide a means for understanding the physics governing these sources. Laboratory measurements of the atomic processes have proved crucial to the interpretation of these spectra. For example using the LLNL electron beam ion traps EBIT-I and EBIT-II a detailed study of the x-ray spectrum of Fe XVII has been conducted addressing the large ratio predicted by theory compared to observations of considerably smaller values of the relative intensity of the 2p-3d {sup 1}P{sub 1} resonant to the {sup 3}D{sub 1} intercombination line. The difference was often attributed to opacity effects. However, laboratory measurements in the optically thin limit agree with observations demonstrating that the prediction is too large and opacity need not be invoked. The laboratory results thus provide a benchmark in the optically thin limit for accurate estimates of opacity effects. To uncover the source of the discrepancy between theory and observation, we have performed a series of experiments that successively uncovered more details about the Fe XVII lines produced in coronal plasmas. …
Date: May 6, 2004
Creator: Brown, G. V.; Beiersdorfer, P.; Chen, H.; Graf, A.; May, M.; Terracol, S. et al.
Object Type: Article
System: The UNT Digital Library
The Level of Taxes in the United States, 1940-2003 (open access)

The Level of Taxes in the United States, 1940-2003

None
Date: July 6, 2004
Creator: Brumbaugh, David L. & Richards, Don C.
Object Type: Report
System: The UNT Digital Library
Immigration: Alien Registration (open access)

Immigration: Alien Registration

This report reviews the process of temporary legal residents becoming registered as U.S. citizens while providing preliminary factors involved before registration.
Date: January 6, 2004
Creator: Bruno, Andorra
Object Type: Report
System: The UNT Digital Library
Immigration Legislation and Issues in the 108th Congress (open access)

Immigration Legislation and Issues in the 108th Congress

None
Date: October 6, 2004
Creator: Bruno, Andorra; Wasem, Ruth Ellen; Siskin, Alison; Ester, Karma; Lee, Margaret Mikyung; Viña, Stephen R. et al.
Object Type: Report
System: The UNT Digital Library
METHANE DE-NOX FOR UTILITY PC BOILERS (open access)

METHANE DE-NOX FOR UTILITY PC BOILERS

The primary focus for the project continues to be on developing a PC PREHEAT system design suitable for use with caking coals and readying the 100 MMBtu/h CBTF for testing with noncaking PRB coal. During the current quarter, twenty-two pilot tests were conducted with Central Appalachian (CA) caking coal. The objective for these tests was to achieve continuous operation of the pilot system at its design coal feed rate of 156 lb/h, without plugging or agglomeration in the combustor. One combustor air distribution method tested achieved continuous operation at 110 lb/hr, and inspection of the combustor afterward indicated that this method has potential to solve the caking problem. The NOx results from the pilot caking coal runs indicate that even greater NOx reduction is possible with CA coal than with the PRB coal tested, to levels near 100 ppmv or lower at 4-6% exit oxygen. It was therefore decided to conduct additional pilot tests of the air distribution method to determine how to incorporate this into a workable CA combustor design. Based on current weather and manpower restrictions at the site, this pilot testing is expected to be started in February. The design for the 100 MMBtu/h unit for PRB …
Date: February 6, 2004
Creator: Bryan, Bruce; Rabovitser, Joseph; Nester, Serguei & Wohadlo, Stan
Object Type: Report
System: The UNT Digital Library
Field Test Program for Long-Term Operation of a COHPAC System for Removing Mercury from Coal-Fired Flue Gas (open access)

Field Test Program for Long-Term Operation of a COHPAC System for Removing Mercury from Coal-Fired Flue Gas

With the Nation's coal-burning utilities facing the possibility of tighter controls on mercury pollutants, the U.S. Department of Energy is funding projects that could offer power plant operators better ways to reduce these emissions at much lower costs. Sorbent injection technology represents one of the simplest and most mature approaches to controlling mercury emissions from coal-fired boilers. It involves injecting a solid material such as powdered activated carbon into the flue gas. The gas-phase mercury in the flue gas contacts the sorbent and attaches to its surface. The sorbent with the mercury attached is then collected by the existing particle control device along with the other solid material, primarily fly ash. During 2001, ADA Environmental Solutions (ADA-ES) conducted a full-scale demonstration of sorbent-based mercury control technology at the Alabama Power E.C. Gaston Station (Wilsonville, Alabama). This unit burns a low-sulfur bituminous coal and uses a hot-side electrostatic precipitator (ESP) in combination with a Compact Hybrid Particulate Collector (COHPAC{reg_sign}) baghouse to collect fly ash. The majority of the fly ash is collected in the ESP with the residual being collected in the COHPAC{reg_sign} baghouse. Activated carbon was injected between the ESP and COHPAC{reg_sign} units to collect the mercury. Short-term mercury removal …
Date: August 6, 2004
Creator: Bustard, Jean; Lindsey, Charles; Brignac, Paul; Starns, Travis; Sjostrom, Sharon; Taylor, Trent et al.
Object Type: Report
System: The UNT Digital Library
Electron exchange along the tercyclopentadienyltrimetallic scaffold: Kinetics, equilibria, and bond strengths (open access)

Electron exchange along the tercyclopentadienyltrimetallic scaffold: Kinetics, equilibria, and bond strengths

None
Date: January 6, 2004
Creator: Cammack, J. Kevin; Amouri, Hani; Leonard, Philip W.; Myrabo, Randy L. & Vollhardt, Peter C.
Object Type: Article
System: The UNT Digital Library
Comparison of Blade-Strike Modeling Results with Empirical Data (open access)

Comparison of Blade-Strike Modeling Results with Empirical Data

This study is the initial stage of further investigation into the dynamics of injury to fish during passage through a turbine runner. As part of the study, Pacific Northwest National Laboratory (PNNL) estimated the probability of blade strike, and associated injury, as a function of fish length and turbine operating geometry at two adjacent turbines in Powerhouse 1 of Bonneville Dam. Units 5 and 6 had identical intakes, stay vanes, wicket gates, and draft tubes, but Unit 6 had a new runner and curved discharge ring to minimize gaps between the runner hub and blades and between the blade tips and discharge ring. We used a mathematical model to predict blade strike associated with two Kaplan turbines and compared results with empirical data from biological tests conducted in 1999 and 2000. Blade-strike models take into consideration the geometry of the turbine blades and discharges as well as fish length, orientation, and distribution along the runner.
Date: May 6, 2004
Creator: Carlson, Thomas J. & Ploskey, Gene R.
Object Type: Report
System: The UNT Digital Library
Simulation of Ventilation Efficiency, Temperatures, and Relative Humidities in Emplacement Drifts at Yucca Mountain, Nevada, Using Monte Carlo and Composite Thermal-Pulse Methods (open access)

Simulation of Ventilation Efficiency, Temperatures, and Relative Humidities in Emplacement Drifts at Yucca Mountain, Nevada, Using Monte Carlo and Composite Thermal-Pulse Methods

Predictions of waste canister and repository driftwall temperatures as a function of space and time are of fundamental importance to evaluating pre-closure and post-closure design requirements and performance assessment of the proposed repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain, Nevada. Variations in the lithostratigraphic features in densely welded and crystallized rocks of the 12.8-million-year-old Topopah Spring Tuff, especially the porosity resulting from lithophysal cavities, are projected 50 to 800 m from the Enhanced Characterization of the Repository Block cross drift to a simulated ''Panel 1'' emplacement drift. Lithophysal cavity porosity varies from 0.00 to 0.05 cm{sup 3}/cm{sup 3} in the middle nonlithophysal zone and from 0.03 to 0.28 cm{sup 3}/cm{sup 3} in the lower lithophysal zone. Many thermal properties are related to lithophysal cavity porosity, and computer code titled ''Monte Carlo Simulation of Ventilation'' (MCSIMVENT) has been developed for simulating statistical variability and uncertainty along the simulated emplacement drift. The MCSIMVENT code, which is based on a composite thermal-pulse calculation, is used to calculate pre-closure ventilation efficiency and peak post-closure temperatures and relative humidities along the simulated emplacement drift for as much as 1,000 years. Variations in lithophysal porosity along the drift can result in …
Date: April 6, 2004
Creator: Case, J. & Buesch, D.
Object Type: Report
System: The UNT Digital Library
Development of Design Criteria for Fluid Induced Structural Vibrations in Steam Generators and Heat Exchangers (open access)

Development of Design Criteria for Fluid Induced Structural Vibrations in Steam Generators and Heat Exchangers

Flow-induced vibration in heat exchangers has been a major cause of concern in the nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported through the USNRC incident reporting system. Almost all heat exchangers have to deal with this problem during their operation. The phenomenon has been studied since the 1970s and the database of experimental studies on flow-induced vibration is constantly updated with new findings and improved design criteria for heat exchangers.
Date: April 6, 2004
Creator: Catton, Uvan; Dhir, Vijay K.; Mitra, Deepanjan; Alquaddoomi, Omar & Adinolfi, Pierangelo
Object Type: Report
System: The UNT Digital Library
New Reactor Design and Analysis of Non Linear Vibrations of Doubly Curved Shallow Shell Under a Thermal Gradient (open access)

New Reactor Design and Analysis of Non Linear Vibrations of Doubly Curved Shallow Shell Under a Thermal Gradient

The present study concerns with the effects of material orthotropy,curvature, shear ratio and circumferential modulus under the influence of a temperature distribution throughout the shell structure. Here analysis is restricted to the study of nonlinear vibration of a doubly curved shell structure considering the periodic response of a simple bending mode due to curtailment of pages. Solutions of the problems with suitable illustrations are also presented.
Date: October 6, 2004
Creator: Chanda, Subhash
Object Type: Article
System: The UNT Digital Library
Asia Pacific Economic Cooperation (APEC), Free Trade, and the 2004 Summit in Santiago, Chile (open access)

Asia Pacific Economic Cooperation (APEC), Free Trade, and the 2004 Summit in Santiago, Chile

This report is on Asia Pacific Economic Cooperation (APEC), Free Trade, and the 2004 Summit in Santiago, Chile.
Date: August 6, 2004
Creator: Chanlett-Avery, Emma
Object Type: Report
System: The UNT Digital Library
Development of a Monolithic Research Reactor Fuel Type at Argonne National Laboratory (open access)

Development of a Monolithic Research Reactor Fuel Type at Argonne National Laboratory

The Reduced Enrichment for Research and Test Reactors (RERTR) program has been tasked with the conversion of research reactors from highly enriched to low-enriched uranium (LEU). To convert several high power reactors, monolithic fuel, a new fuel type, is being developed. This fuel type replaces the standard fuel dispersion with a fuel alloy foil, which allows for fuel densities far in excess of that found in dispersion fuel. The single-piece fuel foil also contains a significantly lower interface area between the fuel and the aluminum in the plate than the standard fuel type, limiting the amount of detrimental fuel-aluminum interaction that can occur. Implementation of monolithic fuel is dependant on the development of a suitable fabrication method as traditional roll-bonding techniques are inadequate.
Date: October 6, 2004
Creator: Clark, C. R. & Briggs, R. J.
Object Type: Article
System: The UNT Digital Library
Strategic Design and Optimization of Inorganic Sorbents for Cesium, Strontium and Actinides (open access)

Strategic Design and Optimization of Inorganic Sorbents for Cesium, Strontium and Actinides

The basic science goal in this project identifies structure/affinity relationships for selected radionuclides and existing sorbents. The task will apply this knowledge to the design and synthesis of new sorbents that will exhibit increased cesium, strontium and actinide removal. The target problem focuses on the treatment of high-level nuclear wastes. The general approach can likewise be applied to non-radioactive separations.
Date: October 6, 2004
Creator: Clearfield, Abraham; Tripathi, Akhilesh; Medvedev, Dmitri; Delgado, Jose & Kerlegon, Steve
Object Type: Report
System: The UNT Digital Library
Letter Report: Scoping Analysis of Gas Phase Transport from the Rulison Underground Nuclear Test (open access)

Letter Report: Scoping Analysis of Gas Phase Transport from the Rulison Underground Nuclear Test

This letter report documents the results of a computer model to quantify the travel time of tritium (radioactive hydrogen) from an underground nuclear detonation in 1969 toward a proposed producing gas well located 1,500 feet (457 meters) away.
Date: May 6, 2004
Creator: Cooper, Clay
Object Type: Report
System: The UNT Digital Library
Clean Water Act Issues in the 108th Congress (open access)

Clean Water Act Issues in the 108th Congress

This report discusses issues regarding the Clean Water Act. Prospects for legislative initiatives to comprehensively amend the Clean Water Act (CWA) have stalled for some time over whether and exactly how to change the law, and Congress has recently focused legislative attention on narrow bills to extend or modify selected CWA programs, rather than taking up comprehensive proposals. For example, the 108th Congress enacted one bill amending the CWA, legislation to reauthorize the National Estuary Program (H.R. 4731, P.L. 108-399).
Date: December 6, 2004
Creator: Copeland, Claudia
Object Type: Report
System: The UNT Digital Library
LUX - A design study for a linac/laser-based ultrafast X-ray source (open access)

LUX - A design study for a linac/laser-based ultrafast X-ray source

A warm, relativistic fluid theory of a nonequilibrium, collisionless plasma is developed to analyze nonlinear plasma waves excited by intense drive beams. The maximum amplitude and wavelength are calculated for nonrelativistic plasma temperatures and arbitrary plasma wave phase velocities. The maximum amplitude is shown to increase in the presence of a laser field. These results set a limit to the achievable gradient in plasma-based accelerators.
Date: August 6, 2004
Creator: Corlett, J. N.; Barletta, W. A.; DeSantis, S.; Doolittle, L.; Fawley, W. M.; Heimann, P. et al.
Object Type: Article
System: The UNT Digital Library
NSPS Increasing Protection Through Shared Awareness (open access)

NSPS Increasing Protection Through Shared Awareness

None
Date: May 6, 2004
Creator: Costa, J E
Object Type: Article
System: The UNT Digital Library
Foreign Terrorist Organizations (open access)

Foreign Terrorist Organizations

This report analyzes the status of many of the major foreign terrorist organizations that are a threat to the United States, placing special emphasis on issues of potential concern to Congress
Date: February 6, 2004
Creator: Cronin, Audrey Kurth; Aden, Huda; Frost, Adam & Jones, Benjamin
Object Type: Report
System: The UNT Digital Library
Comparison of 9/11 Commission Recommended Intelligence Reforms, Roberts Draft Bill, H.R. 4104, S. 190, S. 1520, S. 6, H.R. 4584, and Current Law (open access)

Comparison of 9/11 Commission Recommended Intelligence Reforms, Roberts Draft Bill, H.R. 4104, S. 190, S. 1520, S. 6, H.R. 4584, and Current Law

This report, the first of two reports, presents side-by-side comparisons of the 9/11 Commission recommendations and legislation proposed by Senators Feinstein, Bob Graham, Daschle, and Roberts; and Representatives Harman and Goss, and relevant provisions of current law. A second report (CRS Report RL32601) presents a side-by-side comparison of the 9/11 Commission recommendations and legislation proposed by Senators Collins, Lieberman, and McCain; President Bush; and relevant provisions of current law.
Date: October 6, 2004
Creator: Cumming, Alfred
Object Type: Report
System: The UNT Digital Library
Comparison of 9/11 Commission Recommended Intelligence Reforms, S. 2845, S. 2774, H.R. 5024, Administration Proposal, H.R. 10, Current Law (open access)

Comparison of 9/11 Commission Recommended Intelligence Reforms, S. 2845, S. 2774, H.R. 5024, Administration Proposal, H.R. 10, Current Law

This report, the second of two reports, presents side-by-side comparisons of the 9/11 Commission recommendations and current law and legislation proposed by Senators Collins and Lieberman (S. 2845) and unanimously approved by the Senate Governmental Affairs Committee on September 22, 2004, as amended; House Speaker Dennis Hastert (H.R. 10), as reported out be the House Committee on Rules; Senators McCain and Lieberman (S. 2774); Representative Pelosi (H.R. 5024); and President Bush. CRS Report RL32600 presents side-by-side comparisons of the 9/11 Commission recommendations and current law; and legislation proposed by Senators Feinstein, Bob Graham, Daschle, and Roberts; President Bush; and relevant provisions of current law.
Date: October 6, 2004
Creator: Cumming, Alfred
Object Type: Report
System: The UNT Digital Library
FBI Intelligence Reform Since September 11, 2001: Issues and Options for Congress (open access)

FBI Intelligence Reform Since September 11, 2001: Issues and Options for Congress

None
Date: April 6, 2004
Creator: Cumming, Alfred & Masse, Todd M.
Object Type: Report
System: The UNT Digital Library
MARS, 600 MWth NUCLEAR POWER PLANT (open access)

MARS, 600 MWth NUCLEAR POWER PLANT

MARS (Multipurpose Advanced Reactor, inherently Safe) is a 600 MWth, single loop, pressurized light water reactor (PWR), developed at the Dept. of Nuclear Engineering and Energy Conversion of the University of Rome ''La Sapienza''. The design was focused to a multipurpose reactor to be used in high population density areas also for industrial heat production and, in particular, for water desalting. Using the well-proven technology and the operation experience of PWRs, the project introduces a lot of innovative features hugely improving the safety performance while keeping the cost of KWh competitive with traditional large power plants. Extensive use of passive safety, in depth plant simplification and decommissioning oriented design were the guidelines along the design development. The latest development in the plant design, in the decommissioning aspects and in the experimental activities supporting the project are shown in this paper.
Date: October 6, 2004
Creator: Cumo, M.; Naviglio, A. & Sorabella, L.
Object Type: Article
System: The UNT Digital Library
Mechanical Properties of K Basin Sludge Constituents and Their Surrogates (open access)

Mechanical Properties of K Basin Sludge Constituents and Their Surrogates

A survey of the technical literature was performed to summarize the mechanical properties of inorganic components in K Basins sludge. The components included gibbsite, ferrihydrite, lepidocrocite and goethite, hematite, quartz, anorthite, calcite, basalt, Zircaloy, aluminum, and, in particular, irradiated uranium metal and uranium dioxide. Review of the technical literature showed that information on the hardness of uranium metal at irradiation exposures similar to those experienced by the N Reactor fuel present in the K Basins (typically up to 3000 MWd/t) were not available. Measurements therefore were performed to determine the hardness of coupons taken from three irradiated N Reactor uranium metal fuel elements taken from K Basins. Hardness values averaged 30 {+-} 8 Rockwell C units, similar to values previously reported for uranium irradiated to {approx}1200 MWd/t. The physical properties of candidate uranium metal and uranium dioxide surrogates were gathered and compared. Surrogates having properties closest to those of irradiated uranium metal appear to be alloys of tungsten. The surrogate for uranium dioxide, present both as particles and agglomerates in actual K Basin sludge, likely requires two materials. Cerium oxide, CeO2, was identified as a surrogate of the smaller UO2 particles while steel grit was identified for the UO2 agglomerates.
Date: December 6, 2004
Creator: Delegard, Calvin H.; Schmidt, Andrew J. & Chenault, Jeffrey W.
Object Type: Report
System: The UNT Digital Library