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574
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344
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84
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Trade Liberalization Challenges Post-CAFTA
None
Date:
November 30, 2005
Creator:
Ahearn, Raymond J.
Object Type:
Report
System:
The UNT Digital Library
The German Economy and U.S.-German Economic Relations
This report first examines Germany's economic performance in historical perspective and assesses some of the domestic factors that may be contributing to Germany's suboptimal performance; the second discusses the reform challenges facing Germany's political leaders; and the third section evaluates a few salient U.S.-German economic policy differences and strains that seem to be influenced by Germany's weakened economic situation.
Date:
November 30, 2009
Creator:
Ahearn, Raymond J. & Belkin, Paul
Object Type:
Report
System:
The UNT Digital Library
Developing Supersonic Impactor and Aerodynamic Lens for Separation and Handling of Nano-Sized Particles
A computational model for supersonic flows of compressible gases in an aerodynamic lens with several lenses and in a supersonic/hypersonic impactor was developed. Airflow conditions in the aerodynamic lens were analyzed and contour plots for variation of Mach number, velocity magnitude and pressure field in the lens were evaluated. The nano and micro-particle trajectories in the lens and their focusing and transmission efficiencies were evaluated. The computational model was then applied to design of a aerodynamic lens that could generate focus particle beams while operating under atmospheric conditions. The computational model was also applied to airflow condition in the supersonic/hypersonic impactor. Variations of airflow condition and particle trajectories in the impactor were evaluated. The simulation results could provide understanding of the performance of the supersonic and hypersonic impactors that would be helpful for the design of such systems.
Date:
June 30, 2008
Creator:
Ahmadi, Goodarz
Object Type:
Report
System:
The UNT Digital Library
Fundamentals of Natural Gas and Species Flows from Hydrate Dissociation - Applications to Safety and Sea Floor Instability
Semi-analytical computational models for natural gas flow in hydrate reservoirs were developed and the effects of variations in porosity and permeability on pressure and temperature profiles and the movement of a dissociation front were studied. Experimental data for variations of gas pressure and temperature during propane hydrate formation and dissociation for crushed ice and mixture of crushed ice and glass beads under laboratory environment were obtained. A thermodynamically consistent model for multiphase liquid-gas flows trough porous media was developed. Numerical models for hydrate dissociation process in one dimensional and axisymmetric reservoir were performed. The computational model solved the general governing equations without the need for linearization. A detail module for multidimensional analysis of hydrate dissociation which make use of the FLUENT code was developed. The new model accounts for gas and liquid water flow and uses the Kim-Boshnoi model for hydrate dissociation.
Date:
September 30, 2006
Creator:
Ahmadi, Goodarz
Object Type:
Report
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.
Object Type:
Report
System:
The UNT Digital Library
ACOUSTIC FORMING FOR ENHANCED DEWATERING AND FORMATION
The next generation of forming elements based on acoustic excitation to increase drainage and enhances formation both with on-line control and profiling capabilities has been investigated in this project. The system can be designed and optimized based on the fundamental experimental and computational analysis and investigation of acoustic waves in a fiber suspension flow and interaction with the forming wire.
Date:
November 30, 2007
Creator:
Aidun, Cyrus K
Object Type:
Report
System:
The UNT Digital Library
Thermotunneling Based Cooling Systems for High Efficiency Buildings
GE Global Research's overall objective was to develop a novel thermotunneling-cooling device. The end use for these devices is the replacement of vapor cycle compression (VCC) units in residential and commercial cooling and refrigeration systems. Thermotunneling devices offer many advantages over vapor cycle compression cooling units. These include quiet, reliable, non-moving parts operation without refrigerant gases. Additionally theoretical calculations suggest that the efficiency of thermotunneling devices can be 1.5-2x that of VCC units. Given these attributes it can be seen that thermotunneling devices have the potential for dramatic energy savings and are environmentally friendly. A thermotunneling device consists of two low work function electrodes separated by a sub 10 nanometer-sized gap. Cooling by thermotunneling refers to the transport of hot electrons across the gap, from the object to be cooled (cathode) to the heat rejection electrode (anode), by an applied potential. GE Global Research's goal was to model, design, fabricate devices and demonstrate cooling base on the thermotunneling technology.
Date:
September 30, 2007
Creator:
Aimi, Marco; Arik, Mehmet; Bray, James; Gorczyca, Thomas; Michael, Darryl & Weaver, Stan
Object Type:
Report
System:
The UNT Digital Library
Project Work Plan 100-N Area Strontium-90 Treatability Demonstration Project: Phytoremediation Along the 100-N Columbia River Riparian Zone
The 100-N Area Innovative Treatment and Remediation Demonstration (ITRD) identified phyto¬remediation as a potential technology both for the removal of 90Sr from the soil of the riparian zone and as a filter for groundwater along the Columbia River. Recent greenhouse and growth chamber studies have demonstrated the viability of phytoextraction to remove 90Sr from this area’s soil/water; in conjunction with monitored natural attenuation and an apatite barrier the process would make an effective treatment for remediation of the 100-N Area 90Sr plume. All activities associated with the 100-NR-1 and 100-NR-2 Operable Units of the Hanford 100-N Area have had, and continue to have, significant regulatory and stakeholder participation. Beginning in 1998 with the ITRD process, presentations to the ITRD TAG were heavily attended by EPA, Washington State Department of Ecology, and stakeholders. In addition, three workshops have been held to receive regulatory and stakeholder feedback on monitored natural attenuation, the apatite barrier, and phytoremediation; these were held in Richland in August 2003, December 2004, and August 2005. The apatite injection treatability test plan (DOE 2005) describes phytoremediation as a technology to be evaluated during the March 2008 evaluation milestone as described in the Tri-Party Agreement change request (M-16-06-01 Change Control …
Date:
April 30, 2006
Creator:
Ainsworth, Calvin C.
Object Type:
Report
System:
The UNT Digital Library
Paleo-Climate and Glaciological Reconstruction in Central Asia through the Collection and Analysis of Ice Cores and Instrumental Data from the Tien Shan
While the majority of ice core investigations have been undertaken in the polar regions, a few ice cores recovered from carefully selected high altitude/mid-to-low latitude glaciers have also provided valuable records of climate variability in these regions. A regional array of high resolution, multi-parameter ice core records developed from temperate and tropical regions of the globe can be used to document regional climate and environmental change in the latitudes which are home to the vase majority of the Earth's human population. In addition, these records can be directly compared with ice core records available from the polar regions and can therefore expand our understanding of inter-hemispheric dynamics of past climate changes. The main objectives of our paleoclimate research in the Tien Shan mountains of middle Asia combine the development of detailed paleoenvironmental records via the physical and chemical analysis of ice cores with the analysis of modern meteorological and hydrological data. The first step in this research was the collection of ice cores from the accumulation zone of the Inylchek Glacier and the collection of meteorological data from a variety of stations throughout the Tien Shan. The research effort described in this report was part of a collaborative effort with …
Date:
May 30, 2001
Creator:
Aizen, Vladimir; Bren, Donald; Kreutz, Karl & Wake, Cameron
Object Type:
Report
System:
The UNT Digital Library
Characterizing the fabric of the urban environment: A case studyof Metropolitan Chicago, Illinois and Executive Summary
Urban fabric data are needed in order to estimate the impactof light-colored surfaces (roofs and pavements) and urban vegetation(trees, grass, shrubs) on the meteorology and air quality of a city, andto design effective implementation programs. In this report, we discussthe result of a semi-automatic Monte-Carlo statistical approach used todevelop data on surface-type distribution and city-fabric makeup(percentage of various surface-types) using aerial colororthophotography. The digital aerial photographs for metropolitan Chicagocovered a total of about 36 km2 (14 mi2). At 0.3m resolution, there wereapproximately 3.9 x 108 pixels of data. Four major land-use types wereexamined: commercial, industrial, residential, andtransportation/communication. On average, for the areas studied, atground level vegetation covers about 29 percent of the area (ranging 4 80percent); roofs cover about 25 percent (ranging 8 41 percent), and pavedsurfaces about 33 percent (ranging 12 59 percent). For the most part,trees shade streets, parking lots, grass, and side-walks. In commercialareas, paved surfaces cover 50 60 percent of the area. In residentialareas, on average, paved surfaces cover about 27percent of the area.Land-use/land-cover (LULC) data from the United States Geological Surveywas used to extrapolate these results from neighborhood scales tometropolitan Chicago. In an area of roughly 2500 km2, defining most ofmetropolitan Chicago, over 53 percent …
Date:
October 30, 2001
Creator:
Akbari, Hashem & Rose, Leanna Shea
Object Type:
Report
System:
The UNT Digital Library
Design, Synthesis, and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals
This project extends previously discovered Fe-based catalysts to hydrogen-poor synthesis gas streams derived from coal and biomass sources. These catalysts have shown unprecedented Fischer-Tropsch synthesis rates and selectivities for feedstocks consisting of synthesis gas derived from methane. During the first reporting period, we certified a microreactor, installed required analytical equipment, and reproduced synthetic protocols and catalytic results previously reported. During the second reporting period, we prepared several Fe-based compositions for Fischer-Tropsch Synthesis and tested the effects of product recycle under both subcritical and supercritical conditions. During the third and fourth reporting periods, we improved the catalysts preparation method, which led to Fe-based FT catalysts with the highest FTS reaction rates and selectivities so far reported, a finding that allowed their operation at lower temperatures and pressures with high selectivity to desired products (C{sub 5+}, olefins). During the fifth reporting period, we studied the effects of different promoters on catalytic performance, specifically how their sequence of addition dramatically influenced the performance of these materials in the Fischer-Tropsch synthesis. We also continued our studies of the kinetic behavior of these materials. Specifically, the effects of H{sub 2}, CO, and CO{sub 2} on the rates and selectivities of Fischer-Tropsch Synthesis reactions led us …
Date:
September 30, 2006
Creator:
Akio; Ishikawa; Ojeda, Manuel; Yao, Nan & Iglesia, Enrique
Object Type:
Report
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. Evaluation of these sorbents as catalysts for the selective reduction of NO{sub x} gave promising results with methane. Since the replacement of ammonia by methane is commercially very attractive, in this project, the effect of promoters on the activity and selectivity of copper oxide/cerium oxide-based catalysts and the reaction mechanism for the SCR with methane was investigated. Unpromoted and promoted catalysts were investigated for their SCR activity with methane in a microreactor setup and also, by the temperature-programmed desorption (TPD) technique. The results from the SCR experiments indicated that manganese is a more effective promoter than the other metals (Rh, Li, K, Na, Zn, and Sn) for the supported copper oxide-ceria catalysts under study. The effectiveness of the promoter increased with the increase in Ce/Cu ratio. Among the catalysts tested, the Cu1Ce3 catalyst promoted with 1 weight % Mn was found to be the best catalyst for the SCR of NO with methane. This catalyst was subjected to long-term testing at the facilities of our industrial partner TDA Research. …
Date:
November 30, 2003
Creator:
Akyurtlu, Ates & Akyurtlu, Jale F.
Object Type:
Report
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
Object Type:
Report
System:
The UNT Digital Library
Techniques and use of a tunable, laser-based, MeV-Class Compton scattering light source
A Compton scattering {gamma}-ray source, capable of producing photons with energies ranging from 0.1 MeV to 0.9 MeV has been commissioned and characterized, and then used to perform nuclear resonance fluorescence (NRF) experiments. The key source parameters are the size (0.01 mm{sup 2}), horizontal and vertical divergence (6 x 10 mrad{sup 2}), duration (10 ps), spectrum and intensity (10{sup 5} photons/shot). These parameters are summarized by the peak brightness, 1.5 x 10{sup 15} photons/mm{sup 2}/mrad{sup 2}/s/0.1%bandwidth, measured at 478 keV. Additional measurements of the flux as a function of the timing difference between the drive laser pulse and the relativistic photoelectron bunch, {gamma}-ray beam profile, and background evaluations are presented. These results are systematically compared to theoretical models and computer simulations. NRF measurements performed on {sup 7}Li in LiH demonstrate the potential of Compton scattering photon sources to accurately detect isotopes in situ.
Date:
June 30, 2009
Creator:
Albert, F.; Anderson, S. G.; Gibson, D. J.; Hagmann, C. A.; Johnson, M. S.; Messerly, M. et al.
Object Type:
Article
System:
The UNT Digital Library
Final report: U.S. competitive position in automotive technologies
Patent data are presented and analyzed to assess the U.S. competitive position in eleven advanced automotive technology categories, including automotive fuel cells, hydrogen storage, advanced batteries, hybrid electric vehicles and others. Inventive activity in most of the technologies is found to be growing at a rapid pace, particularly in advanced batteries, automotive fuel cells and ultracapacitors. The U.S. is the clear leader in automotive fuel cells, on-board hydrogen storage and light weight materials. Japan leads in advanced batteries, hybrid electric vehicles, ultracapacitors, and appears to be close to overtaking the U.S. in other areas of power electronics.
Date:
September 30, 2002
Creator:
Albert, Michael B.; Cheney, Margaret; Thomas, Patrick & Kroll, Peter
Object Type:
Report
System:
The UNT Digital Library
Comparison of STIS and SNAP spectrograph throughputs
This is a comparison of the measured throughput of STIS on HST versus what we might expect from the spectrograph on SNAP. The principle reference is Woodgate et al. (1998) PASP, 110, 1183. Additional material was taken from the STIS Handbook, available on-line at www.stsci.edu. The goal is to demonstrate that there are sound reasons to expect better performance for a SNAP spectrograph (even one with a grating) than would be expected by scaling from HST+STIS.
Date:
June 30, 2002
Creator:
Aldering, Greg
Object Type:
Report
System:
The UNT Digital Library
Excitation of the synchro-betatron resonances by the beam-beam interaction in the Tevatron Run II lattice
Effect of different mechanisms of the synchro-betatron coupling (dispersion function at the interaction points, chromatic tune modulation, finite bunch length) on the p-bar stability in the Tevatron Run II configuration is considered. It is found that the long-range interactions in the presence of large dispersion produce large contribution ({approximately}10) to the chromaticity of the betatron tunes. This chromaticity, in its turn, can give rise to multiple synchrotron satellites of the betatron resonances increasing their effective width. Novel formulae are presented which permit to significantly speed up analytical calculations of the beam-beam tuneshifts and resonance strength.
Date:
April 30, 2001
Creator:
Alexahin, Yuri I.
Object Type:
Report
System:
The UNT Digital Library
Use of Artificial Burrows by Burrowing Owls (Athene cunicularia) at the HAMMER Facility on the U.S. Department of Energy Hanford Site
In 2003 the U.S. Department of Energy (DOE) constructed an Emergency Vehicle Operations Course (EVOC) at the Hazardous Material Management and Emergency Response Training and Education Center (HAMMER) in the southern portion of the Hanford Site. Preliminary surveys during 2001 identified an active burrowing owl (Athene cunicularia) burrow and three burrowing owls within the proposed development area. Burrowing owls were classified as a federal species of concern, a Washington State ?candidate? species, a Washington Department of Fish and Wildlife priority species, and a Hanford Site Biological Resources Management Plan Level III resource. Therefore, the mitigation action plan for the project included the installation of twenty artificial burrows around EVOC in the spring of 2003. The mitigation plan established a success criterion of five percent annual use of the burrows by owls. In July 2005, a field survey of the EVOC burrow complex was conducted to determine use and demography at each site. Burrow locations were mapped and signs of activity (feces, owl tracks, castings, feathers) were recorded. Out of the twenty burrows, twelve were found to be active. Of the eight inactive burrows three appeared to have been active earlier in the 2005 breeding season. A total of nineteen owls …
Date:
September 30, 2005
Creator:
Alexander, Amanda K.; Sackschewsky, Michael R. & Duberstein, Corey A.
Object Type:
Report
System:
The UNT Digital Library
Is the world shrinking or are we getting bigger?
None
Date:
January 30, 2009
Creator:
Alexandre, Melanie
Object Type:
Article
System:
The UNT Digital Library
Fabrication of Mo/Cu Multilayer and Bilayer Transition Edge Sensors
We are developing cryogenic high-resolution x-ray, {gamma}-ray and neutron spectrometers based on superconducting Mo/Cu transition edge sensors. Here we discuss the sensor design for different applications, present the photolithographic fabrication techniques, and outline future detector development to increase spectrometer sensitivity.
Date:
September 30, 2004
Creator:
Ali, Z. A.; Drury, O. B.; Cunningham, M. F.; Chesser, J. M.; Barbee, T. W., Jr. & Friedrich, S.
Object Type:
Article
System:
The UNT Digital Library
Tanks Focus Area Site Needs Assessment - FY 2001
The TFA uses a systematic process for developing its annual program that draws from the tanks science and technology development needs expressed by the five DOE tank waste sites. TFA's annual program development process is iterative and involves the following steps: Collection of site needs; Needs analysis; Development of technical responses and initial prioritization; Refinement of the program for the next fiscal year; Formulation of the Corporate Review Budget (CRB); Preparation of Program Execution Guidance (PEG) for the next FY Revision of the Multiyear Program Plan (MYPP). This document describes the outcomes of the first phase of this process, from collection of site needs to the initial prioritization of technical activities. The TFA received site needs in October - December 2000. A total of 170 site needs were received, an increase of 30 over the previous year. The needs were analyzed and integrated, where appropriate. Sixty-six distinct technical responses were drafted and prioritized. In addition, seven strategic tasks were approved to compete for available funding in FY 2002 and FY 2003. Draft technical responses were prepared and provided to the TFA Site Representatives and the TFA User Steering Group (USG) for their review and comment. These responses were discussed at …
Date:
April 30, 2001
Creator:
Allen, Bob W; Josephson, Gary B; Westsik, Joseph H & Nickola, Cheryl L
Object Type:
Report
System:
The UNT Digital Library
Thermodynamics and Structure of Plutonium Alloys
The goal of this project was to investigate the chemical and structural effects of gallium and impurity elements, iron and nickel, on the phase behavior and crystallography of Pu-Ga alloys. This was done utilizing a theoretical chemical approach to predict binary and ternary alloy energetics, phase stability, and transformations. The modeling results were validated with experimental data derived from the synthesis of selected alloys and advanced characterization tools. The ultimate goal of this work was to develop a robust predictive capability for studying the thermodynamics and the structure-properties relationships in complex materials of high relevance to the Laboratory and DOE mission.
Date:
January 30, 2004
Creator:
Allen, P G; Turchi, P A & Gallegos, G F
Object Type:
Report
System:
The UNT Digital Library
Tanks Focus Area Site Needs Assessment - FY 2001
The TFA uses a systematic process for developing its annual program that draws from the tanks science and technology development needs expressed by the five DOE tank waste sites. TFA's annual program development process is iterative and involves the following steps: Collection of site needs; Needs analysis; Development of technical responses and initial prioritization; Refinement of the program for the next fiscal year; Formulation of the Corporate Review Budget (CRB); Preparation of Program Execution Guidance (PEG) for the next FY Revision of the Multiyear Program Plan (MYPP). This document describes the outcomes of the first phase of this process, from collection of site needs to the initial prioritization of technical activities. The TFA received site needs in October - December 2000. A total of 170 site needs were received, an increase of 30 over the previous year. The needs were analyzed and integrated, where appropriate. Sixty-six distinct technical responses were drafted and prioritized. In addition, seven strategic tasks were approved to compete for available funding in FY 2002 and FY 2003. Draft technical responses were prepared and provided to the TFA Site Representatives and the TFA User Steering Group (USG) for their review and comment. These responses were discussed at …
Date:
April 30, 2001
Creator:
Allen, Robert W.; Josephson, Gary B.; Westsik, Joseph H. & Nickola, Cheryl L.
Object Type:
Report
System:
The UNT Digital Library
Groundwater Level Status Report for Fiscal Year 2006 Los Alamos National Laboratory
The status of groundwater level monitoring at Los Alamos National Laboratory in Fiscal Year 2006 is provided in this report. The Groundwater Level Monitoring Project was instituted in 2005 for providing a framework for the collection and processing of quality controlled groundwater level data. This report summarizes groundwater level data for 158 monitoring wells, including 43 regional aquifer wells, 23 intermediate wells, and 92 alluvial wells. Pressure transducers were installed in 132 monitoring wells for continuous monitoring of groundwater levels. Time-series hydrographs of groundwater level data are presented along with pertinent construction and location information for each well.
Date:
March 30, 2007
Creator:
Allen, Shannon P. & Koch, Richard J.
Object Type:
Report
System:
The UNT Digital Library