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Studies of vibrational properties in Ga stabilized delta-Pu by extended X-ray absorption fine structure (open access)

Studies of vibrational properties in Ga stabilized delta-Pu by extended X-ray absorption fine structure

Temperature dependent extended x-ray absorption fine structure (EXAFS) spectra were measured for a 3.3 at. % Ga stabilized Pu alloy over the range T= 20 - 300 K. EXAFS data were acquired at both the Ga K-edge and the Pu L{sub III} edge. Curve-fits were performed to the first shell interactions to obtain pair-distance distribution widths, {sigma}, as a function of temperature. The temperature dependence of {sigma}(T) was accurately modeled using a correlated-Debye model for the lattice vibrational properties, suggesting Debye-like behavior in this material. Using this formalism, we obtain pair-specific correlated-Debye temperatures, {Theta}{sub cD}, of 110.7 {+-} 1.7 K and 202.6 {+-} 3.7 K, for the Pu-Pu and Ga-Pu pairs, respectively. The result for the Pu-{Theta}{sub cD} value compares well with previous vibrational studies on {delta}-Pu. In addition, our results represent the first unambiguous determination of Ga-specific vibrational properties in Pu-Ga alloys, i.e, {Theta}{sub cD} for the Ga-Pu pair. Because the Debye temperature can be related to a measure of the lattice stiffness, these results indicate the Ga-Pu bonds are significantly stronger than the Pu-Pu bonds. This effect has important implications for lattice stabilization mechanisms in these alloys.
Date: February 14, 2002
Creator: Allen, P. G.; Henderson, A. L.; Sylwester, E. R.; Turchi, P. E. A.; Shen, T. H.; Gallegos, G. F. et al.
Object Type: Article
System: The UNT Digital Library
Water and Energy Savings using Demand Hot Water Recirculating Systems in Residential Homes: A Case Study of Five Homes in Palo Alto, California (open access)

Water and Energy Savings using Demand Hot Water Recirculating Systems in Residential Homes: A Case Study of Five Homes in Palo Alto, California

This report summarizes a preliminary study aimed at estimating the potential of saving potable water, (and the electrical energy used to heat it), that is presently lost directly to the drain while occupants wait for hot water to arrive at the faucet (point of use). Data were collected from five single-family homes in Palo Alto, California. Despite the small sample size in this study, the results make a compelling case for retrofitting homes with hot water recirculation systems to eliminate unnecessary wastage of water at the point of use. Technical as well as behavioral and attitudinal changes towards water conservation are necessary for a fulfilling and successful conservation effort. This report focuses on the technical issues, but behavioral issues are also noted, which may be factored into future studies involving local and state governments and utility companies.
Date: November 14, 2002
Creator: Ally, M.R.
Object Type: Report
System: The UNT Digital Library
Digitization of Government Information (open access)

Digitization of Government Information

Report submitted by an American Libraries Association (ALA) Government Documents Round Table (GODORT) ad hoc committee charged to "create a report advising GODORT on the best practices and procedures in the digital library field and advise GODORT on the most effective organizational structure for support of the government information community in pursuing digital library initiatives" (p. 2).
Date: June 14, 2002
Creator: American Library Association. Government Documents Round Table. Ad Hoc Committee on Digitization Of Government Information.
Object Type: Report
System: The UNT Digital Library

Downtown Edmond

Photograph of a scene in Downtown Edmond.
Date: October 14, 2002
Creator: Argo, Jim
Object Type: Photograph
System: The Gateway to Oklahoma History

Downtown Edmond

Photograph of a scene in Downtown Edmond.
Date: October 14, 2002
Creator: Argo, Jim
Object Type: Photograph
System: The Gateway to Oklahoma History
Thermal and Chemical Analyses of Silicone Polymers for Component Engineering Lifetime Assessments (open access)

Thermal and Chemical Analyses of Silicone Polymers for Component Engineering Lifetime Assessments

Accurate predictions of a polymer component's functional lifetime at best arc tenuous when one has only relatively short term chemical or mechanical property data to extrapolate. We have analyzed a series of silica-filled siloxanes to determine the chemical and microstructural signatures of aging, and we are incorporating these data into rational methodologies for assessing a component's lifetime measured against as-designed engineering properties. We are monitoring changes in mechanical properties, crystallization kinetics, cross-link density changes, and motional dynamics with a variety of analysis methods: Modulated DSC, Dynamic Mechanical Analysis, and Solid-state Nuclear Magnetic Resonance. Previous work has shown that the addition of phenyl side groups to polydimethylsiloxane (PDMS) polymer chains reduces the rate and extent of crystallization of the co-polymer compared to that of pure PDMS. Crystallization has been observed in copolymer systems up to 6.5 mol % phenyl composition by DSC and up to 8 mol % phenyl by XRD. The PDMS-PDPS-silica composite materials studied here are silica reinforced random block copolymers consisting of dimethyl and diphenyl monomer units with 11.2 mol. % polydiphenylsiloxane. Based on this previous work, it is not expected that this material would exhibit crystallization in the polymer network; however, these silicones do, in fact, exhibit …
Date: May 14, 2002
Creator: Balazs, B & Maxwell, R S
Object Type: Article
System: The UNT Digital Library
Strategic Petroleum Reserve (open access)

Strategic Petroleum Reserve

None
Date: May 14, 2002
Creator: Bamberger, Robert L.
Object Type: Report
System: The UNT Digital Library
Performance Enhancement of the Automated Concrete Evaluation System (ACES) (open access)

Performance Enhancement of the Automated Concrete Evaluation System (ACES)

The objective of this proposed research is to improve and expand the detection and analysis capabilities of the automated, concrete evaluation (ACE) system. MoDOT and Honeywell jointly developed this system. The focus of this proposed research will be on the following: Coordination of concrete imaging efforts with other states, Validation and testing of the ACE system on a broad range of concrete samples, and Identification and development of software and hardware enhancements. These enhancements will meet the needs of diverse users in the field of concrete materials, construction, and research.
Date: February 14, 2002
Creator: Baumgart,C.W.; Cave,S.P. & Linder,K.E.
Object Type: Report
System: The UNT Digital Library
Country-of-Origin Labeling for Foods (open access)

Country-of-Origin Labeling for Foods

This report provides information about the Country-of-Origin Labeling for Foods. Federal law requires most imports, including many food items to bear labels informing the "ultimate purchaser" of their country of origin.
Date: June 14, 2002
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Country-of-Origin Labeling for Foods (open access)

Country-of-Origin Labeling for Foods

Federal law requires most imports, including many food items, to bear labels informing the “ultimate purchaser” of their country of origin. Meats, produce, and several other raw agricultural products generally have been exempt. The omnibus farm law (P.L. 107-171) signed on May 13, 2002, contains a requirement that many retailers provide, starting on September 30, 2004, country-of-origin labeling (COOL) on fresh fruits and vegetables, red meats, seafood, and peanuts. The program is voluntary until then. USDA on October 8, 2002, issued guidelines for the voluntary labeling program.
Date: June 14, 2002
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Sum-Frequency Generation in Chiral Liquids Near Electronic Resonance (open access)

Sum-Frequency Generation in Chiral Liquids Near Electronic Resonance

None
Date: August 14, 2002
Creator: Belkin, M. A.; Han, S. H.; Wei, X. & Shen, Y. R.
Object Type: Article
System: The UNT Digital Library
Supercritical Solubility of Binders Used in Explosive Formulations (open access)

Supercritical Solubility of Binders Used in Explosive Formulations

The dissolution of polymers in supercritical carbon dioxide was measured using in-situ ultraviolet absorbance. This research was carried out to provide data to support the development of a new process to produce plastic-bonded explosive molding powder. Estane 5703, the polymer used to bind PBX 9501, was insoluble at the tested conditions. The dissolution of Kraton FG 1901 was tested at 27 to 100{degrees}C and 29 to 65 MPa. Only a small fraction of this polymer dissolved, and the quantity that dissolved increased with the polymer sample size. The tested polymer was polydisperse, and it is thought that the lowest molecular weight fraction of the polymer preferentially dissolved. Based on this observation, dissolution of the polymer prior to molding powder synthesis is recommended to obtain a uniform molding powder product. The dissolution of nearly monodisperse samples of polyethylacrylate were tested at 27 to 90{degrees}C and 10 to 65 MPa. The resulting solutions were very dilute, on the order of 100 mg/liter, and the solutions did not reach saturation during the 90 hour test period. The slow approach to saturation indicates that mass transfer rates may significantly affect process performance.
Date: September 14, 2002
Creator: Bell, David A.
Object Type: Report
System: The UNT Digital Library
Public Interaction and Educational Outreach on the Yucca Mountain Project (open access)

Public Interaction and Educational Outreach on the Yucca Mountain Project

In July 2002, the U.S. Congress approved Yucca Mountain in Nevada as the nation's first long-term geologic repository site for spent nuclear fuel and high-level radioactive waste. This major milestone for the country's high-level radioactive waste disposal program comes after more than twenty years of scientific study and intense public interaction and outreach. This paper describes public interaction and outreach challenges faced by the U.S. Department of Energy's (DOE) Yucca Mountain Project in the past and what additional communication strategies may be instituted following the July 2002 approval by the U.S. Congress to develop the site as the nation's first long-term geologic repository for spent nuclear fuel and high-level radioactive waste. The DOE public involvement activities were driven by two federal regulations--the National Environmental Policy Act (NEPA) and the Nuclear Waste Policy Act (NWPA) of 1982, as amended. The NEPA required that DOE hold public hearings at key points in the development of an Environmental Impact Statement (EIS) and the NWPA required the agency to conduct public hearings in the vicinity of the site prior to making a recommendation regarding the site's suitability. The NWPA also provided a roadmap for how DOE would interact with affected units of government, which …
Date: November 14, 2002
Creator: Benson, A. & Riding, Y.
Object Type: Report
System: The UNT Digital Library
Value-Added Tax as a New Revenue Source (open access)

Value-Added Tax as a New Revenue Source

None
Date: November 14, 2002
Creator: Bickley, James M.
Object Type: Report
System: The UNT Digital Library
A Value-Added Tax Contrasted with a National Sales Tax (open access)

A Value-Added Tax Contrasted with a National Sales Tax

Proposals to replace all or part of the income tax and proposals for national health care have sparked congressional interest in possible sources of additional revenue. A value-added tax (VAT) or a national sales tax (NST) have been frequently discussed as possible new tax sources. Both the VAT and the NST are taxes on the consumption of goods and services and are conceptually similar. Yet, these taxes also have significant differences. This issue brief discusses some of the potential policy implications associated with these differences.
Date: November 14, 2002
Creator: Bickley, James M.
Object Type: Report
System: The UNT Digital Library
The low-energy undulator test line : a SASE FEL operating from 660 to 130 nm. (open access)

The low-energy undulator test line : a SASE FEL operating from 660 to 130 nm.

None
Date: August 14, 2002
Creator: Biedron, S. G.; Borland, M.; Den Hartog, P.; Dejus, R.; Erdmann, M.; Huang, Z. et al.
Object Type: Article
System: The UNT Digital Library
Penetration of liquid fingers into superheated fracturedrock (open access)

Penetration of liquid fingers into superheated fracturedrock

Water infiltrating down a fracture in unsaturated rock experiences complex fluid-flow and heat-transfer phenomena when entering above-boiling rock temperature regions. Such conditions are expected, for example, after emplacement of heat-generating nuclear waste in underground repositories. A new, efficient semi-analytical method is proposed in this paper that simulates the flow processes of infiltration events subject to vigorous boiling from the adjacent hot rock. It is assumed that liquid flow forms in localized preferential flow paths, and that infiltration events are typically short in duration but large in magnitude relative to the average net infiltration. The new solution scheme is applied to several test cases studying sensitivity to a variety of input parameters. Sample simulations are performed for conditions representative of the potential nuclear waste repository at Yucca Mountain, Nevada. A characteristic parameter is introduced that provides a quick estimate of the relative significance of boiling at a given location of interest.
Date: November 14, 2002
Creator: Birkholzer, Jens
Object Type: Article
System: The UNT Digital Library
Oral History Interview with Alfred Bisili, August 14, 2002 transcript

Oral History Interview with Alfred Bisili, August 14, 2002

The National Museum of the Pacific War presents an interview with Alfred Bisili. Bisili was born in Munda, New Georgia, Western Province, Solomon Islands in December of 1923. He recalls the Japanese invading in 1942, the Americans arriving in 1943, and his family hiding in the bush. Bisili, and a number of other natives, joined the American Army’s 118th Engineer Battalion, 43rd Infantry Division. He served as a scout for the island, and led the troops on Baanga Island, through the New Georgia Campaign, and until the end of the war. Reference Jimmy Bennett’s oral history, a native friend of Bisili, who participated with him during the war.
Date: August 14, 2002
Creator: Bisili, Alfred
Object Type: Sound
System: The Portal to Texas History
Oral History Interview with Alfred Bisili, August 14, 2002 (open access)

Oral History Interview with Alfred Bisili, August 14, 2002

The National Museum of the Pacific War presents an interview with Alfred Bisili. Bisili was born in Munda, New Georgia, Western Province, Solomon Islands in December of 1923. He recalls the Japanese invading in 1942, the Americans arriving in 1943, and his family hiding in the bush. Bisili, and a number of other natives, joined the American Army’s 118th Engineer Battalion, 43rd Infantry Division. He served as a scout for the island, and led the troops on Baanga Island, through the New Georgia Campaign, and until the end of the war. Reference Jimmy Bennett’s oral history, a native friend of Bisili, who participated with him during the war.
Date: August 14, 2002
Creator: Bisili, Alfred
Object Type: Text
System: The Portal to Texas History
Anomalous momentum dependence of the quasiparticle scattering ratein overdoped Bi2Sr2CaCu2O8 (open access)

Anomalous momentum dependence of the quasiparticle scattering ratein overdoped Bi2Sr2CaCu2O8

The question of the anisotropy of the electron scattering in high temperature superconductors is investigated using high resolution angle-resolved photoemission data from Pb-doped Bi2Sr2CaCu2O8(Bi2212) with suppressed superstructure. The scattering rate of low energy electrons along two bilayer split pieces of the Fermi surface is measured (via the quasiparticle peak width), and no increase of scattering towards the antinode (Pi,0) region is observed, contradicting the expectation from Q=(Pi, Pi) scattering. The results put a limit on the effects of Q=(Pi, Pi) scattering on the electronic structure of this overdoped superconductor with still very high Tc.
Date: October 14, 2002
Creator: Bogdanov, P. V.; Lanzara, A.; Zhou, X. J.; Yang, W. L.; Eisaki, H.; Hussain, Z. et al.
Object Type: Article
System: The UNT Digital Library
Army Aviation: The RAH-66 Comanche Helicopter Issue (open access)

Army Aviation: The RAH-66 Comanche Helicopter Issue

Although it has been a high priority Army program, a number of factors have complicated the RAH-66 Comanche program. Since its inception, the program has been restructured several times–postponing the initial operational capability (IOC) and increasing overall program costs. Presently, there is debate within the Army regarding whether the program should be reduced significantly to make funds available to pursue other modernization priorities.
Date: November 14, 2002
Creator: Bolkcom, Christopher
Object Type: Report
System: The UNT Digital Library
F-22 Raptor Aircraft Program (open access)

F-22 Raptor Aircraft Program

This report discusses the background information, analysis and the recent developments in the F-22 Raptor Aircraft Program. The F-22 program raises questions about its cost and the need for this aircraft, the capabilities it would have, and the number of these planes needed to meet military requirements. The F-22 has had strong congressional support, although some have criticized the program on grounds of cost, requirements, and coordination with other tactical aircraft programs. Deletion of procurement funds in the FY2000 defense appropriation bill passed by the House made the future of the program a major issue for House and Senate conferees in 1999.
Date: January 14, 2002
Creator: Bolkcom, Christopher
Object Type: Report
System: The UNT Digital Library
Tactical Aircraft Modernization: Issues for Congress (open access)

Tactical Aircraft Modernization: Issues for Congress

None
Date: January 14, 2002
Creator: Bolkcom, Christopher
Object Type: Report
System: The UNT Digital Library
V-22 Osprey Tilt-Rotor Aircraft (open access)

V-22 Osprey Tilt-Rotor Aircraft

The V-22 Osprey is a tilt-rotor aircraft that takes off and lands vertically like a helicopter and flies like a plane by tilting its wing-mounted rotorsto function as propellers. Combining a helicopter’s operational flexibility with the greaterspeed,range, and efficiency of fixed-wing aircraft, the V-22 can perform such missions astroop/cargo transport, amphibious assault, special operations, and search and rescue operations.
Date: January 14, 2002
Creator: Bolkcom, Christopher
Object Type: Report
System: The UNT Digital Library