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16,032 Matching Results
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Trade and the Americas
None
Date:
April 8, 2002
Creator:
Ahearn, Raymond J.
Object Type:
Report
System:
The UNT Digital Library
U.S.-European Union Trade Relations: Issues and Policy Challenges
None
Date:
April 6, 2005
Creator:
Ahearn, Raymond J.
Object Type:
Report
System:
The UNT Digital Library
Task 1 Final Report, Theoretical/Mathematical Modeling of Ultrasonic Wave Propagation in Anisotropic Polycrystalline Stainless Steels
One of the tasks of the U.S. Nuclear Regulatory Commission-sponsored project titled "Reliability of Nondestructive Examination (NDE) for Nuclear Power Plant (NPP) Inservice Examination (ISI)" is to provide collaborative assistance to Commissariat à l’Energie Atomique (CEA) in France through theoretical predictions of ultrasonic scattering by grains of cast stainless steels (CASS) components. More specifically, a mathematical treatment of ultrasonic scattering in media having duplex micro¬structure is sought because cast stainless steel components often contains larger-scale macrograins that are composed of sub-grains/colonies. In this report, we present formal mathematical theories for ultrasonic wave propagation in polycrystalline aggregates having both simple (composed of grains only) and complex microstructures (having macrograins and sub-grains/colonies). Computations based on these theories are then carried out for ultrasonic backscatter power, attenuation due to scattering, and phase velocity dispersions. Specifically, numerical results are presented for backscatter coefficient for plane longitudinal wave propagating in duplex steel containing macrograins and colonies. Furthermore, the expected propagation characteristics (attenuation coefficient and phase velocity) are computed and described in this report for plane longitudinal waves propagating in (1) steels composed of randomly oriented grains, (2) [001] aligned grains encountered in austenitic stainless steel welds and casts, and (3) duplex steels.
Date:
April 20, 2009
Creator:
Ahmed, Salahuddin & Anderson, Michael T.
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
Notes on Switching between Proton and gold Operation in Booster and AGS
N/A
Date:
April 1, 2000
Creator:
Ahrens, L. A. & Gardner, C. J.
Object Type:
Report
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.
Object Type:
Report
System:
The UNT Digital Library
System Requirements Document for the Molten Salt Reactor Experiment
The purpose of the conversion process is to convert the {sup 233}U fluoride compounds that are being extracted from the Molten Salt Reactor Experiment (MSRE) equipment to a stable oxide for long-term storage at Bldg. 3019.
Date:
April 1, 2000
Creator:
Aigner, R. D.
Object Type:
Report
System:
The UNT Digital Library
Separation of Carbon Dioxide from Flue Gas Using Ion Pumping
We are developing a new way of separating carbon dioxide from flue gas based on ionic pumping of carbonate ions dissolved in water. Instead of relying on large temperature or pressure changes to remove carbon dioxide from solvent used to absorb it from flue gas, the ion pump increases the concentration of dissolved carbonate ion in solution. This increases the overlying vapor pressure of carbon dioxide gas, which can be removed from the downstream side of the ion pump as a nearly pure gas. This novel approach to increasing the concentration of the extracted gas permits new approaches to treating flue gas. The slightly basic water used as the extraction medium is impervious to trace acid gases that destroy existing solvents, and no pre-separation is necessary. The simple, robust nature of the process lends itself to small separation plants. Although the energy cost of the ion pump is significant, we anticipate that it will be compete favorably with the current 35% energy penalty of chemical stripping systems in use at power plants. There is the distinct possibility that this simple method could be significantly more efficient than existing processes.
Date:
April 21, 2006
Creator:
Aines, R.; Bourcier, W. L. & Johnson, M. R.
Object Type:
Article
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
Multi-Model Combination techniques for Hydrological Forecasting: Application to Distributed Model Intercomparison Project Results
This paper examines several multi-model combination techniques: the Simple Multi-model Average (SMA), the Multi-Model Super Ensemble (MMSE), Modified Multi-Model Super Ensemble (M3SE) and the Weighted Average Method (WAM). These model combination techniques were evaluated using the results from the Distributed Model Intercomparison Project (DMIP), an international project sponsored by the National Weather Service (NWS) Office of Hydrologic Development (OHD). All of the multi-model combination results were obtained using uncalibrated DMIP model outputs and were compared against the best uncalibrated as well as the best calibrated individual model results. The purpose of this study is to understand how different combination techniques affect the skill levels of the multi-model predictions. This study revealed that the multi-model predictions obtained from uncalibrated single model predictions are generally better than any single member model predictions, even the best calibrated single model predictions. Furthermore, more sophisticated multi-model combination techniques that incorporated bias correction steps work better than simple multi-model average predictions or multi-model predictions without bias correction.
Date:
April 11, 2005
Creator:
Ajami, N. K.; Duan, Q.; Gao, X. & Sorooshian, S.
Object Type:
Article
System:
The UNT Digital Library
Variation of nominal contact pressure with time during sliding wear.
None
Date:
April 9, 2001
Creator:
Ajayi, O. O. & Erck, R. A.
Object Type:
Article
System:
The UNT Digital Library
Optical Imaging in Microstructures
This research was focused on developing morphology-dependent stimulated raman scattering (MDSRS) spectroscopy as an analytic optical imaging technique. MDSRS uses the cavity modes (called morphology dependent resonances, MDRs) associated with axisymmetric dielectric microstructures to generate nonlinear optical signals. Since different cavity modes span different regions inside the microstructure, it becomes possible to generate location-specific spectra. The information gotten from MDSRS imaging experiments is analogous with that generated from magnetic resonance imaging (MRI) studies in that spatial variations in chemical composition and molecular configuration within a structure can be mapped out. The authors demonstrated that MDSRS imaging is feasible and is free from nonlinear artifact. They did this by measuring the molecular structure variations that are present in the interfaces of 180 {micro}m dia. charged water droplets. The 4 publications that resulted from these studies are attached. From a chemical perspective a water droplet is, however, a simple thing. Will it be possible to use MDSRS imaging to study more complex systems such as combusting fuel droplets, layered polymer or glass fibers, or biological cells? The long-term goal of the research was to answer this question. The answer they have come up with is yes and no. The results on nitrate …
Date:
April 11, 2001
Creator:
Aker, P. M.
Object Type:
Report
System:
The UNT Digital Library
PRODUCTION OF NEW BIOMASS/WASTE-CONTAINING SOLID FUELS
CQ Inc. and its team members (ALSTOM Power Inc., Bliss Industries, McFadden Machine Company, and industry advisors from coal-burning utilities, equipment manufacturers, and the pellet fuels industry) addressed the objectives of the Department of Energy and industry to produce economical, new solid fuels from coal, biomass, and waste materials that reduce emissions from coal-fired boilers. This project builds on the team's commercial experience in composite fuels for energy production. The electric utility industry is interested in the use of biomass and wastes as fuel to reduce both emissions and fuel costs. In addition to these benefits, utilities also recognize the business advantage of consuming the waste byproducts of customers both to retain customers and to improve the public image of the industry. Unfortunately, biomass and waste byproducts can be troublesome fuels because of low bulk density, high moisture content, variable composition, handling and feeding problems, and inadequate information about combustion and emissions characteristics. Current methods of co-firing biomass and wastes either use a separate fuel receiving, storage, and boiler feed system, or mass burn the biomass by simply mixing it with coal on the storage pile. For biomass or biomass-containing composite fuels to be extensively used in the U.S., especially …
Date:
April 20, 2001
Creator:
Akers, David J.; Shirey, Glenn A.; Zitron, Zalman & Maney, Charles Q.
Object Type:
Report
System:
The UNT Digital Library
Cell Design to Maximize Capacity in CDMA Networks
This presentation discusses the code division multiple access (CDMA) inter-cell effects, capacity regions, maximizing network capacity, mobility, a call admission control algorithm, and network performance.
Date:
April 2002
Creator:
Akl, Robert G.
Object Type:
Presentation
System:
The UNT Digital Library
WiFi and WCDMA Network Design
This presentation discusses WiFi access point selection and traffic balancing, multi-cell wideband code division multiple access (WCDMA) with multiple classes, user modeling using 2D Gaussian distribution, and intra-cell and inter-cell interference and capacity.
Date:
April 2005
Creator:
Akl, Robert G.
Object Type:
Presentation
System:
The UNT Digital Library
Indoor Propagation Modeling at 2.4 GHZ for IEEE 802.11 Networks
This paper discusses indoor propagation modeling.
Date:
April 2006
Creator:
Akl, Robert G.; Tummala, Dinesh & Li, Xinrong
Object Type:
Paper
System:
The UNT Digital Library
MAGNETO-CHEMICAL CHARACTER STUDIES OF NOVEL Fe CATALYSTS FOR COAL LIQUEFACTION
The objectives of the present study are: (1) To synthesize iron catalysts: Fe/MoO{sub 3}, and Fe/Co/MoO{sub 3} employing two distinct techniques: Pyrolysis with organic precursors and Co-precipitation of metal nitrates; (2) To investigate the magnetic character of the catalysts before and after exposure to CO and CO+H{sub 2} by (a) Mossbauer study of Iron (b) Zerofield Nuclear Magnetic Resonance study of Cobalt, and (c) Magnetic character of the catalyst composite; (3) To study the IR active surface species of the catalyst while stimulating (CO--Metal, (CO+H{sub 2})--Metal) interactions, by FTIR Spectroscopy; and (4) To analyze the catalytic character (conversion efficiency and product distribution) in both direct and indirect liquefaction Process and (5) To examine the correlations between the magnetic and chemical characteristics. This report presents the results of our investigation on (a) the effect of metal loading (b) the effect of intermetallic ratio and (c) the effect of catalyst preparation procedure on (i) the magnetic character of the catalyst composite (ii) the IR active surface species of the catalyst and (iii) the catalytic yields for three different metal loadings: 5%, 15%, and 25% (nominal) for three distinct intermetallic ratios (Fe/Co = 0.3, 1.5, 3.0).
Date:
April 1, 2002
Creator:
Akundi, Murty A.; Zhang, Jian H.; Murty, A.N. & Naidu, S.V.
Object Type:
Report
System:
The UNT Digital Library
Investigation of Mixed Metal Sorbent / Catalysts for the Simultaneous Removal of Sulfur and Nitrogen Oxides
Simultaneous removal of SO{sub 2} and NO{sub x} using a regenerable solid sorbent will constitute an important improvement over the use of separate processes for the removal of these two pollutants from stack gases and possibly eliminate several shortcomings of the individual SO{sub 2} and NO{sub x} removal operations. The work done at PETC and the DOE-funded investigation of the investigators on the sulfation and regeneration of alumina-supported cerium oxide sorbents have shown that they can perform well at relatively high temperatures (823-900 K) as regenerable desulfurization sorbents. Survey of the recent literature shows that addition of copper oxide to ceria lowers the sulfation temperature of ceria down to 773 K, sulfated ceria-based sorbents can function as selective SCR catalysts even at elevated temperatures, SO{sub 2} can be directly reduced to sulfur by CO on CuO-ceria catalysts, and ceria-based catalysts may have a potential for selective catalytic reduction of NO{sub x} by methane. These observations indicate a possibility of developing a ceria-based sorbent/catalyst which can remove both SO{sub 2} and NO{sub x} from flue gases within a relatively wide temperature window, produce significant amounts of elemental sulfur during regeneration, and use methane for the selective catalytic reduction of NO{sub x}. …
Date:
April 10, 2000
Creator:
Akyurtlu, Ates & Akyurtlu, Jale F.
Object Type:
Report
System:
The UNT Digital Library
Laboratory directed research and development fy1999 annual report
The Lawrence Livermore National Laboratory (LLNL) was founded in 1952 and has been managed since its inception by the University of California (UC) for the U.S. Department of Energy (DOE). Because of this long association with UC, the Laboratory has been able to recruit a world-class workforce, establish an atmosphere of intellectual freedom and innovation, and achieve recognition in relevant fields of knowledge as a scientific and technological leader. This environment and reputation are essential for sustained scientific and technical excellence. As a DOE national laboratory with about 7,000 employees, LLNL has an essential and compelling primary mission to ensure that the nation's nuclear weapons remain safe, secure, and reliable and to prevent the spread and use of nuclear weapons worldwide. The Laboratory receives funding from the DOE Assistant Secretary for Defense Programs, whose focus is stewardship of our nuclear weapons stockpile. Funding is also provided by the Deputy Administrator for Defense Nuclear Nonproliferation, many Department of Defense sponsors, other federal agencies, and the private sector. As a multidisciplinary laboratory, LLNL has applied its considerable skills in high-performance computing, advanced engineering, and the management of large research and development projects to become the science and technology leader in those areas …
Date:
April 11, 2000
Creator:
Al-Ayat, R. A.
Object Type:
Report
System:
The UNT Digital Library
Smart Energy Management of Multiple Full Cell Powered Applications
In this research project the University of South Alabama research team has been investigating smart energy management and control of multiple fuel cell power sources when subjected to varying demands of electrical and thermal loads together with demands of hydrogen production. This research has focused on finding the optimal schedule of the multiple fuel cell power plants in terms of electric, thermal and hydrogen energy. The optimal schedule is expected to yield the lowest operating cost. Our team is also investigating the possibility of generating hydrogen using photoelectrochemical (PEC) solar cells through finding materials for efficient light harvesting photoanodes. The goal is to develop an efficient and cost effective PEC solar cell system for direct electrolysis of water. In addition, models for hydrogen production, purification, and storage will be developed. The results obtained and the data collected will be then used to develop a smart energy management algorithm whose function is to maximize energy conservation within a managed set of appliances, thereby lowering O/M costs of the Fuel Cell power plant (FCPP), and allowing more hydrogen generation opportunities. The Smart Energy Management and Control (SEMaC) software, developed earlier, controls electrical loads in an individual home to achieve load management objectives …
Date:
April 23, 2007
Creator:
Alam, MOhammad S.
Object Type:
Report
System:
The UNT Digital Library
Smart Energy Management of Multiple Full Cell Powered Applications
In this research project the University of South Alabama research team has been investigating smart energy management and control of multiple fuel cell power sources when subjected to varying demands of electrical and thermal loads together with demands of hydrogen production. This research has focused on finding the optimal schedule of the multiple fuel cell power plants in terms of electric, thermal and hydrogen energy. The optimal schedule is expected to yield the lowest operating cost. Our team is also investigating the possibility of generating hydrogen using photoelectrochemical (PEC) solar cells through finding materials for efficient light harvesting photoanodes. The goal is to develop an efficient and cost effective PEC solar cell system for direct electrolysis of water. In addition, models for hydrogen production, purification, and storage will be developed. The results obtained and the data collected will be then used to develop a smart energy management algorithm whose function is to maximize energy conservation within a managed set of appliances, thereby lowering O/M costs of the Fuel Cell power plant (FCPP), and allowing more hydrogen generation opportunities. The Smart Energy Management and Control (SEMaC) software, developed earlier, controls electrical loads in an individual home to achieve load management objectives …
Date:
April 23, 2007
Creator:
Alam, Mohammad S.
Object Type:
Report
System:
The UNT Digital Library
Smart Fuel Cell Operated Residential Micro-Grid Community
To build on the work of year one by expanding the smart control algorithm developed to a micro-grid of ten houses; to perform a cost analysis; to evaluate alternate energy sources; to study system reliability; to develop the energy management algorithm, and to perform micro-grid software and hardware simulations.
Date:
April 13, 2005
Creator:
Alam, Mohammad S.
Object Type:
Report
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 Annual report summarizes the research performed from 17 April 2005 through 16 April 2006. Major portions of the research in several of the project's current eight tasks have been completed. We have successfully developed the meteorological inputs using the best possible modeling configurations, resulting in improved representation of atmospheric processes. The development of the variable-grid-resolution emissions model, SMOKE-VGR, is also completed. The development of the MAQSIP-VGR has been completed and a test run was performed to ensure the functionality of this air quality model. We have incorporated new emission data base to update the offshore emissions. However, we have faced some bottleneck problems in the testing the integrity of the new database. For this reason, we have asked for a no cost extension of this project to tackle these scientific problems. Thus, the project is on a one-year delay schedule. During the reporting period, we solved all problems related to the new emission database. We are ready to move to developing the final product, implementation and testing of the variable grid technology into the Community Multiscale Air Quality Model (CMAQ) to develop the CMAQ-VGR. During the upcoming months we will perform the first CMAQ-VGR simulations over the Houston-Galveston region …
Date:
April 16, 2006
Creator:
Alapaty, Kiran
Object Type:
Report
System:
The UNT Digital Library
Observation of the decay Xi0 ---> Sigma+ mu- anti-nu(mu)
The {Xi}{sup 0} muon semi-leptonic decay has been observed for the first time with nine identified events using the KTeV beam line and detector at Fermilab. The decay is normalized to the {Xi}{sup 0} beta decay mode and yields a value for the ratio of decay rates {Lambda}({Xi}{sup 0} {yields} {Sigma}{sup +}{mu}{sup -}{bar {nu}}{sub {mu}})/{Lambda}({Xi}{sup 0} {yields} {Sigma}{sup +}e{sup -} {bar {nu}}{sub e}) of (1.8{sub -0.5}{sup +0.7}(stat.) {+-} 0.2(syst.)) x 10{sup -2} at the 68% confidence level. This is in agreement with the SU(3) flavor symmetric quark model.
Date:
April 1, 2005
Creator:
Alavi-Harati, A.; Alexopoulos, T.; Arenton, M.; Barbosa, R. F.; Barker, A. R.; Barrio, M. et al.
Object Type:
Article
System:
The UNT Digital Library