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Level densities and gamma-ray strength functions in 170,171,172-Yb
Level densities and radiative strength functions in {sup 171}Yb and {sup 170}Yb nuclei have been measured using the {sup 171}Yb({sup 3}He{sup 3}He{gamma}){sup 171}Yb and {sup 171}Yb({sup 3}He,{alpha}{gamma}){sup 170}Yb reactions. New data on {sup 171}Yb are compared to a previous measurement for {sup 171}Yb from the {sup 172}Yb({sup 3}He,{alpha}{gamma}){sup 171}Yb reaction. Systematics of level densities and radiative strength functions in {sup 170,171,172}Yb are established. The entropy excess in {sup 171}Yb relative to the even-even nuclei {sup 170,172}Yb due to the unpaired neutron quasiparticle is found to be approximately 2k{sub B}. Results for the radiative strength function from the two reactions lead to consistent parameters characterizing the ''pygmy'' resonances. Pygmy resonances in the {sup 170,172}Yb populated by the ({sup 3}He,{alpha}) reaction appear to be split into two components for both of which a complete set of resonance parameters are obtained.
Date:
July 28, 2004
Creator:
Agvaanluvsan, U.; Schiller, A.; Becker, J.; Bernstein, L.; Garrett, P.; Guttormsen, M. et al.
System:
The UNT Digital Library
Trade and the Americas
At the 1994 Summit of the Americas, 34 hemispheric democracies agreed to create a “Free Trade Area of the Americas” (FTAA) no later than 2005. If created, the FTAA would be a $13 trillion market of 34 countries (Cuba is not included) and nearly 800 million people. The population alone would make it the largest free trade area in the world with nearly twice the 450 million population of the now 25-nation European Union. In the nearly ten years following the 1994 summit, Western Hemisphere trade ministers have met eight times to advance the negotiating process. At the last ministerial held from November 17- 20 2003 in Miami, ministers agreed to a declaration that set a September 2004 deadline for the market access talks, created a two-tiered FTAA structure, and reaffirmed countries’ commitment to complete the entire FTAA by January 2005.
Date:
October 19, 2004
Creator:
Ahearn, Raymond J.
System:
The UNT Digital Library
U.S.-European Union Trade Relations: Issues and Policy Challenges
This report includes information regarding issues and policy challenges with U.S.-European trade relations. Growing strains, resolving longstanding disputes, and strengthening the multilateral trading system are among topics discussed in this report.
Date:
June 8, 2004
Creator:
Ahearn, Raymond J.
System:
The UNT Digital Library
U.S.-European Union Trade Relations: Issues and Policy Challenges
None
Date:
December 23, 2004
Creator:
Ahearn, Raymond J.
System:
The UNT Digital Library
U.S.- Thailand Free Trade Agreement Negotiations
This report examines Thailand’s economy and trade orientation, the scope and significance of the U.S.-Thai commercial relationship, and the likely top issues in the negotiations. The report concludes with a short summary of the Congressional role and interest in the FTA.
Date:
September 1, 2004
Creator:
Ahearn, Raymond J. & Morrison, Wayne M.
System:
The UNT Digital Library
Search for X-ray induced decay of the 31-yr isomer of 178Hf using synchrotron radiation
Isomeric {sup 178}Hf (t{sub 1/2} = 31 yr, E{sub x} = 2.446 MeV, J{sup {pi}} = 16{sup +}) was bombarded by a white beam of x-rays from the Advanced Photon Source at Argonne National Laboratory. A search was made for x-ray induced decay of the isomer by detecting prompt and delayed {gamma} rays associated with the decay. No induced decay was observed. Upper limits for such a process for x-ray energies between 7-100 keV were set. The limits between 7 and 30 keV are below {approx} 3 x 10{sup -27} cm{sup 2}-keV for induced decay that bypasses the 4-s isomer and {approx} 5 x 10{sup -27} cm{sup 2}-keV for induced decay that is delayed through this isomer, orders of magnitude below values at which induced decay was reported previously. These limits are consistent with what is known about the properties of atomic nuclei.
Date:
September 13, 2004
Creator:
Ahmad, I.; Banar, J. C.; Becker, J. A.; Bredeweg, T. A.; Cooper, J. R.; Gemmell, D. S. et al.
System:
The UNT Digital Library
Advanced Computational Model for Three-Phase Slurry Reactors Progress Report: October 2004
In this project, an Eulerian-Lagrangian formulation for analyzing three-phase slurry flows in a bubble column was developed. The approach used an Eulerian analysis of liquid flows in the bubble column, and made use of the Lagrangian trajectory analysis for the bubbles and particle motions. The bubble-bubble and particle-particle collisions are included the model. The model predictions are compared with the experimental data and good agreement was found An experimental setup for studying two-dimensional bubble columns was developed. The multiphase flow conditions in the bubble column were measured using optical image processing and Particle Image Velocimetry techniques (PIV). A simple shear flow device for bubble motion in a constant shear flow field was also developed. The flow conditions in simple shear flow device were studied using PIV method. Concentration and velocity of particles of different sizes near a wall in a duct flow was also measured. The technique of Phase-Doppler anemometry was used in these studies. An Eulerian volume of fluid (VOF) computational model for the flow condition in the two-dimensional bubble column was also developed. The liquid and bubble motions were analyzed and the results were compared with observed flow patterns in the experimental setup. Solid-fluid mixture flows in ducts …
Date:
October 1, 2004
Creator:
Ahmadi, Goodarz
System:
The UNT Digital Library
Early Entrance Coproduction Plant, Phase II Quarterly Report: Number 17
The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstocks. The objectives of Phase I were to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan for implementation in Phase II; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The work performed under Phase II will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and/or other carbonaceous feedstocks. The objective of Phase III is to develop an …
Date:
January 26, 2004
Creator:
Ahmed, Mushtaq; Anderson, John H.; Berry, Earl R.; Raybold, Troy; Shah, Lalit S. & Yackly, Kenneth A.
System:
The UNT Digital Library
Hydrogen Storage in metal-modified single-walled carbon nanotubes
It has been known for over thirty years that potassium-intercalated graphites can readily adsorb and desorb hydrogen at {approx}1 wt% at 77 K. These levels are much higher than can be attained in pure graphite, owing to a larger thermodynamic enthalpy of adsorption. This increased enthalpy may allow hydrogen sorption at higher temperatures. Potassium has other beneficial effects that enable the design of a new material: (a) Increased adsorption enthalpy in potassium-intercalated graphite compared to pure graphite reduces the pressure and increases the temperature required for a given fractional coverage of hydrogen adsorption. We expect the same effects in potassium-intercalated SWNTs. (b) As an intercalant, potassium separates c-axis planes in graphite. Potassium also separates the individual tubes of SWNTs ropes producing swelling and increased surface area. Increased surface area provides more adsorption sites, giving a proportionately higher capacity. The temperature of adsorption depends on the enthalpy of adsorption. The characteristic temperature is roughly the adsorption enthalpy divided by Boltzmann's constant, k{sub B}. For the high hydrogen storage capacity of SWNTs to be achieved at room temperature, it is necessary to increase the enthalpy of adsorption. Our goal for this project was to use metal modifications to the carbon surface of …
Date:
April 30, 2004
Creator:
Ahn, Dr.
System:
The UNT Digital Library
Towards enhancing Sandia's capabilities in multiscale materials modeling and simulation.
We report our conclusions in support of the FY 2003 Science and Technology Milestone ST03-3.5. The goal of the milestone was to develop a research plan for expanding Sandia's capabilities in materials modeling and simulation. From inquiries and discussion with technical staff during FY 2003 we conclude that it is premature to formulate the envisioned coordinated research plan. The more appropriate goal is to develop a set of computational tools for making scale transitions and accumulate experience with applying these tools to real test cases so as to enable us to attack each new problem with higher confidence of success.
Date:
January 1, 2004
Creator:
Aidun, John Bahram; Fang, Huei Eliot; Barbour, John Charles; Westrich, Henry Roger & Chen, Er-Ping
System:
The UNT Digital Library
Large batch dimensional metrology demonstrated in the example of a LIGA fabricated spring.
Deep x-ray lithography in combination with electroforming is capable of producing high precision metal parts in small lot series. This study deals with a high aspect ratio structure with overall dimensions on the order of 10 mm x 7 mm x 1.5 mm, with the smallest line width being 150 {micro}m. The lateral deviation from the design is to be kept to a minimum, preferably below 5 {micro}m. To ensure adequate quality control, a semi-automated metrology technique has been established to measure all parts. While the paper will give a brief overview of all involved techniques, it focuses on the method to measure the top and bottom of the parts and the top of geometries following the process. The instrument used is a View Engineering Voyager V6x12 microscope, which is fully programmable. The microscope allows direct measurement of geometries but also is capable of saving all captured data as point clouds. These point clouds play a central role when evaluating part geometry. After measuring the part, the point cloud is compared to the computer aided design (CAD) contour of the part, using a commercially available software package. The challenge of proper edge lighting on a nickel alloy part is evaluated …
Date:
April 1, 2004
Creator:
Aigeldinger, Georg; Skala, Dawn M. & Ceremuga, Joseph T.
System:
The UNT Digital Library
Final-part metrology for LIGA springs, Build Group 1.
The LIGA spring is a recently designed part for defense program applications. The Sandia California LIGA team has produced an initial group build of these nickel alloy parts. These are distinctive in having a macroscopic lateral size of about 1 cm, while requiring microscopic dimensional precision on the order of a few micrometers. LIGA technology capabilities at Sandia are able to manufacture such precise structures. While certain aspects of the LIGA process and its production capabilities have been dimensionally characterized in the past, [1-6] the present work is exclusive in defining a set of methods and techniques to inspect and measure final LIGA nickel alloy parts in large prototype quantities. One hundred percent inspection, meaning that every single LIGA part produced needs to be measured, ensures quality control and customer satisfaction in this prototype production run. After a general visual inspection of the parts and an x-ray check for voids, high precision dimensional metrology tools are employed. The acquired data is analyzed using both in house and commercially available software. Examples of measurements illustrating these new metrology capabilities are presented throughout the report. These examples furthermore emphasize that thorough inspection of every final part is not only essential to characterize …
Date:
March 1, 2004
Creator:
Aigeldinger, Georg; Skala, Dawn M.; Ceremuga, Joseph T. & Mills, Bernice E.
System:
The UNT Digital Library
Monitoring the Energy-Use Effects of Cool Roofs on California Commercial Buildings
Solar-reflective roofs stay cooler in the sun than solar-absorptive roofs. Such ''cool'' roofs achieve lower surface temperatures that reduce heat conduction into the building and the building's cooling load. The California Energy Commission has funded research in which Lawrence Berkeley National Laboratory (LBNL) has measured the electricity use and peak demand in commercial buildings to document savings from implementing the Commission's Cool Roofs program. The study seeks to determine the savings achieved by cool roofs by monitoring the energy use of a carefully selected assortment of buildings participating in the Cool Roofs program. Measurements were needed because the peak savings resulting from the application of cool roofs on different types of buildings in the diverse California climate zones have not been well characterized to date. Only a few occupancy categories (e.g., office and retail buildings) have been monitored before this, and those were done under a limited number of climatic conditions. To help rectify this situation, LBNL was tasked to select the buildings to be monitored, measure roof performance before and after replacing a hot roof by a cool roof, and document both energy and peak demand savings resulting from installation of cool roofs. We monitored the effects of cool …
Date:
July 1, 2004
Creator:
Akbari, Hashem; Levinson, Ronnen; Konopaki, Steve & Rainer, Leo
System:
The UNT Digital Library
Development of a Novel Catalyst for NO Decomposition
Air pollution arising from the emission of nitrogen oxides as a result of combustion taking place in boilers, furnaces and engines, has increasingly been recognized as a problem. New methods to remove NO{sub x} emissions significantly and economically must be developed. The current technology for post-combustion removal of NO is the selective catalytic reduction (SCR) of NO by ammonia or possibly by a hydrocarbon such as methane. The catalytic decomposition of NO to give N{sub 2} will be preferable to the SCR process because it will eliminate the costs and operating problems associated with the use of an external reducing species. The most promising decomposition catalysts are transition metal (especially copper)-exchanged zeolites, perovskites, and noble metals supported on metal oxides such as alumina, silica, and ceria. The main shortcoming of the noble metal reducible oxide (NMRO) catalysts is that they are prone to deactivation by oxygen. It has been reported that catalysts containing tin oxide show oxygen adsorption behavior that may involve hydroxyl groups attached to the tin oxide. This is different than that observed with other noble metal-metal oxide combinations, which have the oxygen adsorbing on the noble metal and subsequently spilling over to the metal oxide. This observation …
Date:
October 22, 2004
Creator:
Akyurtlu, Ates & Akyurtlu, Jale F.
System:
The UNT Digital Library
Development of a Novel Catalyst for NO Decomposition
Air pollution arising from the emission of nitrogen oxides as a result of combustion taking place in boilers, furnaces and engines, has increasingly been recognized as a problem. New methods to remove NO{sub x} emissions significantly and economically must be developed. The current technology for post-combustion removal of NO is the selective catalytic reduction (SCR) of NO by ammonia or possibly by a hydrocarbon such as methane. The catalytic decomposition of NO to give N{sub 2} will be preferable to the SCR process because it will eliminate the costs and operating problems associated with the use of an external reducing species. The most promising decomposition catalysts are transition metal (especially copper)-exchanged zeolites, perovskites, and noble metals supported on metal oxides such as alumina, silica, and ceria. The main shortcoming of the noble metal reducible oxide (NMRO) catalysts is that they are prone to deactivation by oxygen. It has been reported that catalysts containing tin oxide show oxygen adsorption behavior that may involve hydroxyl groups attached to the tin oxide. This is different than that observed with other noble metal-metal oxide combinations, which have the oxygen adsorbing on the noble metal and subsequently spilling over to the metal oxide. This observation …
Date:
May 1, 2004
Creator:
Akyurtlu, Ates & Akyurtlu, Jale F.
System:
The UNT Digital Library
Sandia National Laboratories Laboratory Directed Research and Development Program Annual Report: 2003
None
Date:
July 30, 2004
Creator:
Al-Ayat, R
System:
The UNT Digital Library
Relaxation nuclear magnetic resonance imaging (R-NMRI) of desiccation in M9787 silicone pads.
The production and aging of silicone materials remains an important issue in the weapons stockpile due to their utilization in a wide variety of components and systems within the stockpile. Changes in the physical characteristics of silicone materials due to long term desiccation has been identified as one of the major aging effects observed in silicone pad components. Here we report relaxation nuclear magnetic resonance imaging (R-NMRI) spectroscopy characterization of the silica-filled and unfilled polydimethylsiloxane (PDMS) and polydiphenylsiloxane (PDPS) copolymer (M9787) silicone pads within desiccating environments. These studies were directed at providing additional details about the heterogeneity of the desiccation process. Uniform NMR spin-spin relaxation time (T2) images were observed across the pad thickness indicating that the drying process is approximately uniform, and that the desiccation of the M9787 silicone pad is not a H2O diffusion limited process. In a P2O5 desiccation environment, significant reduction of T2 was observed for the silica-filled and unfilled M9787 silicone pad for desiccation up to 225 days. A very small reduction in T2 was observed for the unfilled copolymer between 225 and 487 days. The increase in relative stiffness with desiccation was found to be higher for the unfilled copolymer. These R-NMRI results are …
Date:
June 1, 2004
Creator:
Alam, Todd M; Cherry, Brian Ray & Alam, Mary Kathleen
System:
The UNT Digital Library
Quantification of ammonia binding sites in Davison (Type 3A) zeolite desiccant : a solid-state Nitrogen-15 MAS NMR spectroscopy investigation.
The quantitative analysis of ammonia binding sites in the Davison (Type 3A) zeolite desiccant using solid-state {sup 15}N MAS NMR spectroscopy is reported. By utilizing 15N enriched ammonia ({sup 15}NH{sub 3}) gas, the different adsorption/binding sites within the zeolite were investigated as a function of NH{sub 3} loading. Using {sup 15}N MAS NMR multiple sites were resolved that have distinct cross-polarization dynamics and chemical shift behavior. These differences in the {sup 15}N NMR were used to characterize the adsorption environments in both the pure 3A zeolite and the silicone-molded forms of the desiccant.
Date:
January 1, 2004
Creator:
Alam, Todd Michael; Holland, Gregory P. & Cherry, Brian Ray
System:
The UNT Digital Library
Modeling the Transport and Chemical Evolution of Onshore and Offshore Emissions and their Impact on Local and Regional Air Quality Using a Variable-Grid-Resolution Air Quality Model
This semiannual report summarizes the research performed from 17 April through 16 October 2004. Major portions of the research in several of the project's current eight tasks have been completed, and the results obtained are briefly presented. We have successfully developed the meteorological inputs using the best possible modeling configurations, resulting in improved representation of atmospheric processes. Ingestion of satellite-derived sea surface temperatures in conjunction with the use of our new surface data assimilation technique have resulted in largely improved meteorological inputs to drive the MAQSIP-VGR. The development of the variable-grid-resolution emissions model, SMOKE-VGR, is also largely complete. We expect to develop the final configuration of the SMOKE-VGR during the upcoming reporting period. We are in the process of acquiring the newly released emissions database and offshore emissions data sets to update our archives. The development of the MAQSIP-VGR has been completed and a test run was performed to ensure the functionality of this air quality model. During the upcoming reporting period, we expect to perform the first MAQSIP-VGR simulations over the Houston-Galveston region to study the roles of the meteorology, offshore emissions, and chemistry-transport interactions that determine the temporal and spatial evolution of ozone and its precursors.
Date:
October 16, 2004
Creator:
Alapaty, Kiran
System:
The UNT Digital Library
MODELING THE TRANSPORT AND CHEMICAL EVOLUTION OF ONSHORE AND OFFSHORE EMISSIONS AND THEIR IMPACT ON LOCAL AND REGIONAL AIR QUALITY USING A VARIABLE-GRID-RESOLUTION AIR QUALITY MODEL
None
Date:
May 17, 2004
Creator:
Alapaty, Kiran
System:
The UNT Digital Library
Boundary Layer Cloudiness Parameterizations Using ARM Observations
This study used DOE ARM data and facilities to: (1) study macroscopic properties of continental stratus clouds at SGP and the factors controlling these properties, (2) develop a scientific basis for understanding the processes responsible for the formation of boundary layer clouds using ARM observations in conjunction with simple parametric models and LES, and (3) evaluate cumulus cloud characteristics retrieved from the MMCR operating at TWP-Nauru. In addition we have used high resolution 94 GHz observations of boundary layer clouds and precipitation to: (1) develop techniques for using high temporal resolution Doppler velocities to study large-eddy circulations and turbulence in boundary layer clouds and estimate the limitations of using current and past MMCR data for boundary layer cloud studies, (2) evaluate the capability and limitations of the current MMCR data for estimating reflectivity, vertical velocities, and spectral under low- signal-to-noise conditions associated with weak no n-precipitating clouds, (3) develop possible sampling modes for the new MMCR processors to allow for adequate sampling of boundary layer clouds, and (4) retrieve updraft and downdraft structures under precipitating conditions.
Date:
September 15, 2004
Creator:
Albrecht, Bruce
System:
The UNT Digital Library
The neutrino factory and beta beam experiments and development
The long-term prospects for fully exploring three-flavor mixing in the neutrino sector depend upon an ongoing and increased investment in the appropriate accelerator R&D. Two new concepts have been proposed that would revolutionize neutrino experiments, namely the Neutrino Factory and the Beta Beam facility. These new facilities would dramatically improve our ability to test the three-flavor mixing framework, measure CP violation in the lepton sector, and perhaps determine the neutrino mass hierarchy, and, if necessary, probe extremely small values of the mixing angle {theta}{sub 13}. The stunning sensitivity that could be achieved with a Neutrino Factory is described, together with our present understanding of the corresponding sensitivity that might be achieved with a Beta Beam facility. In the Beta Beam case, additional study is required to better understand the optimum Beta Beam energy, and the achievable sensitivity. Neither a Neutrino Factory nor a Beta Beam facility could be built without significant R&D. An impressive Neutrino Factory R&D effort has been ongoing in the U.S. and elsewhere over the last few years and significant progress has been made towards optimizing the design, developing and testing the required accelerator components, and significantly reducing the cost. The recent progress is described here.
Date:
November 1, 2004
Creator:
Albright, C.; Barger, V.; Beacom, J. F.; Berg, J. S.; Black, E.; Blondel, A. et al.
System:
The UNT Digital Library
Neutrino Factory and Beta Beam Experiments and Development.
The long-term prospects for fully exploring three-flavor mixing in the neutrino sector depend upon an ongoing and increased investment in the appropriate accelerator R&D. Two new concepts have been proposed that would revolutionize neutrino experiments, namely the Neutrino Factory and the Beta Beam facility. These new facilities would dramatically improve our ability to test the three-flavor mixing framework, measure CP violation in the lepton sector, and perhaps determine the neutrino mass hierarchy, and, if necessary, probe extremely small values of the mixing angle {theta}{sub 13}. The stunning sensitivity that could be achieved with a Neutrino Factory is described, together with our present understanding of the corresponding sensitivity that might be achieved with a Beta Beam facility. In the Beta Beam case, additional study is required to better understand the optimum Beta Beam energy, and the achievable sensitivity. Neither a Neutrino Factory nor a Beta Beam facility could be built without significant R&D. An impressive Neutrino Factory R&D effort has been ongoing in the U.S. and elsewhere over the last few years and significant progress has been made towards optimizing the design, developing and testing the required accelerator components, and significantly reducing the cost. The recent progress is described here. There …
Date:
September 21, 2004
Creator:
Albright, C.; Berg, J. S.; Fernow, R.; Gallardo, J.; Kahn, S.; Kirk, H. et al.
System:
The UNT Digital Library
Radiation dose measurements of the insertion devices using radiachromic film dosimeters.
The Advanced Photon Source (APS) uses Nd-Fe-B permanent magnets in the insertion devices to produce x-rays for scientific research [1,2]. Earlier investigations have exhibited varying degrees of demagnetization of these magnets [3] due to irradiation from electron beams [4,5,6], {sup 60}Co {gamma}-rays [5], and high-energy neutrons [7,8]. Radiation-induced demagnetization has been observed in the APS insertion devices [9] and was first measured in December of 2001. Partial demagnetization has also been observed in insertion devices at the European Synchrotron Radiation Facility (ESRF) [4,6], where Nd-Fe-B permanent magnets are also used. Growing concern for the lifetime of APS insertion devices, as well as the permanent magnets that will be used in next-generation, high-power light sources, like the FEL [10,11], resulted from the partial demagnetization observations made at both facilities. This concern in relation to radiation-induced demagnetization spurred a long-term project to measure and analyze the absorbed doses received by the APS insertion devices. The project required a reliable photon high-dose dosimetry technique capable of measuring absorbed doses greater than 10{sup 6} rad, which was not readily available at the APS. Through a collaboration with the National Institute of Standards and Technology (NIST), one such technique using radiachromic films was considered, tested, …
Date:
May 25, 2004
Creator:
Alderman, J.; Semones, E. & Job, P. K.
System:
The UNT Digital Library