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2,606 Matching Results
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Multipole Shimming of Permanent Magnets Using Harmonic CorrectorRings
Shimming systems are required to provide sufficient fieldhomogeneity for high resolution NMR. In certain specialized applications,such as rotating-field NMR and portable (ex-situ) NMR, permanentmagnet-based shimming systems can provide considerable advantages. Wepresent a simple two-dimensional shimming method based on harmoniccorrector rings which can provide arbitrary multipole order shimmingcorrections. Results demonstrate, for example, that quadrupolar ordershimming improves the linewidth by up to and order of magnitude. Anadditional order of magnitude reduction is in principle achievable byultilizing this shimming method for z-gradient correction and higherorder xy gradients.
Date:
October 23, 2006
Creator:
Jachmann, Rebecca C.; Trease, David R.; Bouchard, Louis-S.; Sakellariou, Dimitris; Martin, Rachel W.; Schlueter, Ross D. et al.
Object Type:
Article
System:
The UNT Digital Library
Quantifying the Diffusion of a Fluid through Membranes by RemoteDetection MRI
We present a method to measure self-diffusion acrossmembranes without the need for concentration or pressure gradients.Hyperpolarized xenon in combination with remote detection of NMR allowsthe measurement of membrane permeation, even in the gas phase. Theresulting images allow quantification of the amount of fluid diffusedthrough the membrane, and represent an alternative, potentially moreprecise way of measuring a membrane diffusion coefficient. The use ofremote detection of NMR allows for non-invasive signal encoding coupledto sensitive detection, making this approach ideal for the study ofdiffusion in intact devices such as fuel cells or separationsystems.
Date:
October 24, 2006
Creator:
Telkki, Ville-Veikko; Hilty, Christian; Garcia, Sandra; Harel,Elad & Pines, Alexander
Object Type:
Article
System:
The UNT Digital Library
Modeling the Integrated Performance of Dispersion and Monolithic U-Mo Based Fuels
The evaluation and prediction of integrated fuel performance is a critical component of the Reduced Enrichment for Research and Test Reactors (RERTR) program. The PLATE code is the primary tool being developed and used to perform these functions. The code is being modified to incorporate the most recent fuel/matrix interaction correlations as they become available for both aluminum and aluminum/silicon matrices. The code is also being adapted to treat cylindrical and square pin geometries to enhance the validation database by including the results gathered from various international partners. Additional modeling work has been initiated to evaluate the thermal and mechanical performance requirements unique to monolithic fuels during irradiation.
Date:
October 1, 2006
Creator:
Wachs, Daniel M.; Burkes, Douglas E.; Hayes, Steven L.; Moore, Karen; Miller, Greg; Hofman, Gerard et al.
Object Type:
Article
System:
The UNT Digital Library
Waste Isolation Pilot Plant 2005 Site Environmental Report
The purpose of this report is to provide information needed by the DOE to assess WIPP's environmental performance and to make WIPP environmental information available to stakeholders and members of the public. This report has been prepared in accordance with DOE Order 231.1A and DOE guidance. This report documents WIPP's environmental monitoring programs and their results for 2004. The WIPP Project is authorized by the DOE National Security and Military Applications of Nuclear Energy Authorization Act of 1980 (Pub. L. 96-164). After more than 20 years of scientific study and public input, WIPP received its first shipment of waste on March 26, 1999. Located in southeastern New Mexico, WIPP is the nation's first underground repository permitted to safely and permanently dispose of TRU radioactive and mixed waste (as defined in the WIPP LWA) generated through defense activities and programs. TRU waste is defined, in the WIPP LWA, as radioactive waste containing more than 100 nanocuries (3,700 becquerels [Bq]) of alpha-emitting TRU isotopes per gram of waste, with half-lives greater than 20 years except for high-level waste, waste that has been determined not to require the degree of isolation required by the disposal regulations, and waste the U.S. Nuclear Regulatory Commission …
Date:
October 13, 2006
Creator:
Services, Washington Regulatory and Environmental
Object Type:
Report
System:
The UNT Digital Library
In Vivo Characterization of Human APOA5 Haplotypes
Increased plasma triglycerides concentrations are an independent risk factor for cardiovascular disease. Numerous studies support a reproducible genetic association between two minor haplotypes in the human apolipoprotein A5 gene (APOA5) and increased plasma triglyceride concentrations. We thus sought to investigate the effect of these minor haplotypes (APOA5*2 and APOA5*3) on ApoAV plasma levels through the precise insertion of single-copy intact APOA5 haplotypes at a targeted location in the mouse genome. While we found no difference in the amount of human plasma ApoAV in mice containing the common APOA5*1 and minor APOA5*2 haplotype, the introduction of the single APOA5*3 defining allele (19W) resulted in 3-fold lower ApoAV plasma levels consistent with existing genetic association studies. These results indicate that S19W polymorphism is likely to be functional and explain the strong association of this variant with plasma triglycerides supporting the value of sensitive in vivo assays to define the functional nature of human haplotypes.
Date:
October 1, 2006
Creator:
Ahituv, Nadav; Akiyama, Jennifer; Chapman-Helleboid, Audrey; Fruchart, Jamila & Pennacchio, Len A.
Object Type:
Article
System:
The UNT Digital Library
DiMES Studies of Temperature Dependence of Carbon Erosion and Re-Deposition in the DIII-D Divertor
A strong effect of a moderately elevated surface temperature on net carbon deposition and deuterium co-deposition in the DIII-D divertor was observed under detached conditions. A DiMES sample with a gap 2 mm wide and 18 mm deep was exposed to lower-single-null (LSN) L-mode plasmas first at room temperature, and then at 200 C. At the elevated temperature, deuterium co-deposition in the gap was reduced by an order of magnitude. At the plasma-facing surface of the heated sample net carbon erosion was measured at a rate of 3 nm/s, whereas without heating net deposition is normally observed under detachment. In a related experiment three sets of molybdenum mirrors recessed 2 cm below the divertor floor were exposed to identical LSN ELMy H-mode discharges. The first set of mirrors exposed at ambient temperature exhibited net carbon deposition at a rate of up to 3.7 nm/s and suffered a significant drop in reflectivity. In contrast, two other mirror sets exposed at elevated temperatures between 90 C and 175 C exhibited virtually no carbon deposition.
Date:
October 2, 2006
Creator:
Rudakov, D.; Jacob, W.; Krieger, K.; Litnovsky, A.; Philipps, V.; West, W. et al.
Object Type:
Article
System:
The UNT Digital Library
Experimental Breeder Reactor I Preservation Plan
Experimental Breeder Reactor I (EBR I) is a National Historic Landmark located at the Idaho National Laboratory, a Department of Energy laboratory in southeastern Idaho. The facility is significant for its association and contributions to the development of nuclear reactor testing and development. This Plan includes a structural assessment of the interior and exterior of the EBR I Reactor Building from a preservation, rather than an engineering stand point and recommendations for maintenance to ensure its continued protection.
Date:
October 1, 2006
Creator:
Braun, Julie
Object Type:
Report
System:
The UNT Digital Library
The Reactivity of Energetic Materials At Extreme Conditions
Energetic materials are unique for having a strong exothermic reactivity, which has made them desirable for both military and commercial applications. Energetic materials are commonly divided into high explosives, propellants, and pyrotechnics. We will focus on high explosive (HE) materials here, although there is a great deal of commonality between the classes of energetic materials. Although the history of HE materials is long, their condensed-phase properties are poorly understood. Understanding the condensed-phase properties of HE materials is important for determining stability and performance. Information regarding HE material properties (for example, the physical, chemical, and mechanical behaviors of the constituents in plastic-bonded explosive, or PBX, formulations) is necessary for efficiently building the next generation of explosives as the quest for more powerful energetic materials (in terms of energy per volume) moves forward. In modeling HE materials there is a need to better understand the physical, chemical, and mechanical behaviors from fundamental theoretical principles. Among the quantities of interest in plastic-bonded explosives (PBXs), for example, are thermodynamic stabilities, reaction kinetics, equilibrium transport coefficients, mechanical moduli, and interfacial properties between HE materials and the polymeric binders. These properties are needed (as functions of stress state and temperature) for the development of improved micro-mechanical …
Date:
October 23, 2006
Creator:
Fried, L E
Object Type:
Article
System:
The UNT Digital Library
A High-Speed Detector System for X-ray Fluorescence Microprobes.
We have developed a high-speed system for collecting x-ray fluorescence microprobe data, based on ASICs developed at BNL and high-speed processors developed by CSIRO. The system can collect fluorescence data in a continuous raster scan mode, and present elemental images in real time using Ryan's Dynamic Analysis algorithm. We will present results from a 32-element prototype array illustrating the concept. The final instrument will have 384 elements arranged in a square array around a central hole.
Date:
October 29, 2006
Creator:
Siddons, P. D.; Dragone, A.; De Geronimo, G.; Kuczewski, A. & Kuczewski, J.
Object Type:
Article
System:
The UNT Digital Library
Do grain boundaries in nanophase metals slide?
Nanophase metallic materials show a maximum in strength as grain size decreases to the nano scale, indicating a break down of the Hall-Petch relation. Grain boundary sliding, as a possible accommodation mechanisms, is often the picture that explain computer simulations results and real experiments. In a recent paper, Bringa et al. Science 309, 1838 (2005), we report on the observation of an ultra-hard behavior in nanophase Cu under shock loading, explained in terms of a reduction of grain boundary sliding under the influence of the shock pressure. In this work we perform a detailed study of the effects of hydrostatic pressure on nanophase Cu plasticity and find that it can be understood in terms of pressure dependent grain boundary sliding controlled by a Mohr-Coulomb law.
Date:
October 27, 2006
Creator:
Bringa, E M; Leveugle, E & Caro, A
Object Type:
Article
System:
The UNT Digital Library
GeV electron beams from a laser-plasma accelerator
High-quality electron beams with up to 1 GeV energy havebeen generated by a laser-driven plasma-based accelerator by guiding a 40TW peak power laser pulse in a 3.3 cm long gas-filled capillary dischargewaveguide.
Date:
October 1, 2006
Creator:
Schroeder, C. B.; Tóth, Cs.; Nagler, B.; Gonsalves, A. J.; Nakamura, K.; Geddes, C. G. R. et al.
Object Type:
Article
System:
The UNT Digital Library
Development of a Fan-Filter Unit Test Standard, Laboratory Validations, and its Applications across Industries
Lawrence Berkeley National Laboratory (LBNL) is now finalizing the Phase 2 Research and Demonstration Project on characterizing 2-foot x 4-foot (61-cm x 122-cm) fan-filter units in the market using the first-ever standard laboratory test method developed at LBNL.[1][2][3] Fan-filter units deliver re-circulated air and provide particle filtration control for clean environments. Much of the energy in cleanrooms (and minienvironments) is consumed by 2-foot x 4-foot (61-cm x 122-cm) or 4-foot x 4-foot (122-cm x 122-cm) fan-filter units that are typically located in the ceiling (25-100% coverage) of cleanroom controlled environments. Thanks to funding support by the California Energy Commission's Industrial Program of the Public Interest Energy Research (PIER) Program, and significant participation from manufacturers and users of fan-filter units from around the world, LBNL has developed and performed a series of standard laboratory tests and reporting on a variety of 2-foot x 4-foot (61-cm x 122-cm) fan-filter units (FFUs). Standard laboratory testing reports have been completed and reported back to anonymous individual participants in this project. To date, such reports on standard testing of FFU performance have provided rigorous and useful data for suppliers and end users to better understand, and more importantly, to quantitatively characterize performance of FFU products …
Date:
October 20, 2006
Creator:
Xu, Tengfang
Object Type:
Article
System:
The UNT Digital Library
A Local Corrections Algorithm for Solving Poisson's Equation inThree Dimensions
We present a second-order accurate algorithm for solving thefree-space Poisson's equation on a locally-refined nested grid hierarchyin three dimensions. Our approach is based on linear superposition oflocal convolutions of localized charge distributions, with the nonlocalcoupling represented on coarser grids. There presentation of the nonlocalcoupling on the local solutions is based on Anderson's Method of LocalCorrections and does not require iteration between different resolutions.A distributed-memory parallel implementation of this method is observedto have a computational cost per grid point less than three times that ofa standard FFT-based method on a uniform grid of the same resolution, andscales well up to 1024 processors.
Date:
October 30, 2006
Creator:
McCorquodale, Peter; Colella, Phillip; Balls, Gregory T. & Baden,Scott B.
Object Type:
Article
System:
The UNT Digital Library
Facilitation of the Estuary/Ocean Subgroup for Research, Monitoring, and Evaluation, FY06 Annual Report
This annual report is a deliverable for fiscal year 2006 (FY06) for Project 2002-077-00, Facilitation of the Estuary/Ocean Subgroup (EOS). The EOS is part of the research, monitoring, and evaluation (RME) effort the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to the 2000 and 2004 Biological Opinions on operation of the Federal Columbia River Power System. The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates implementation of the Estuary RME Plan. In FY06, EOS project accomplishments included: 1) subgroup meetings; 2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; 3) project management via the project tracking system, PISCES; 4) quarterly project status reports; and 5) a major revision to the Estuary RME Plan (new version May 2006) based on comments by EOS members, the Independent Scientific Review Panel, and other reviewers. In the context of uncertainty about the direction of the federal RME due to litigation on the FCRPS Biological Opinion, FY06 activities for the EOS project resulted in expanded substantive coordination with other regional RME forums, project tracking infrastructure, and a new version of the …
Date:
October 3, 2006
Creator:
Johnson, Gary E.
Object Type:
Report
System:
The UNT Digital Library
Cracking and Corrosion of Composite Tubes in Black Liquor Recovery Boiler Primary Air Ports
This report addresses the cracking and corrosion of composite tubes in black liquor recovery boiler primary air ports.
Date:
October 1, 2006
Creator:
Keiser, James R.; Singbeil, Douglas; Gorti, Sarma B.; Kish, Joseph R.; Yuan, Jianwei; Frederick, Laurel A. et al.
Object Type:
Report
System:
The UNT Digital Library
Clean Coal Diesel Demonstration Project
A Clean Coal Diesel project was undertaken to demonstrate a new Clean Coal Technology that offers technical, economic and environmental advantages over conventional power generating methods. This innovative technology (developed to the prototype stage in an earlier DOE project completed in 1992) enables utilization of pre-processed clean coal fuel in large-bore, medium-speed, diesel engines. The diesel engines are conventional modern engines in many respects, except they are specially fitted with hardened parts to be compatible with the traces of abrasive ash in the coal-slurry fuel. Industrial and Municipal power generating applications in the 10 to 100 megawatt size range are the target applications. There are hundreds of such reciprocating engine power-plants operating throughout the world today on natural gas and/or heavy fuel oil.
Date:
October 31, 2006
Creator:
Wilson, Robert
Object Type:
Report
System:
The UNT Digital Library
Quantum Mechanical Single Molecule Partition Function from Path Integral Monte Carlo Simulations
An algorithm for calculating the partition function of a molecule with the path integral Monte Carlo method is presented. Staged thermodynamic perturbation with respect to a reference harmonic potential is utilized to evaluate the ratio of partition functions. Parallel tempering and a new Monte Carlo estimator for the ratio of partition functions are implemented here to achieve well converged simulations that give an accuracy of 0.04 kcal/mol in the reported free energies. The method is applied to various test systems, including a catalytic system composed of 18 atoms. Absolute free energies calculated by this method lead to corrections as large as 2.6 kcal/mol at 300 K for some of the examples presented.
Date:
October 1, 2006
Creator:
Chempath, Shaji; Bell, Alexis T. & Predescu, Cristian
Object Type:
Article
System:
The UNT Digital Library
Germanium-Based Detectors for Gamma-Ray Imaging andSpectroscopy
Germanium-based detectors are the standard technology usedfor gamma-ray spectroscopy when high efficiency and excellent energyresolution are desired. By dividing the electrical contacts on thesedetectors into segments, the locations of the gamma-ray interactionevents within the detectors can be determined as well as the depositedenergies. This enables simultaneous gamma-ray imaging and spectroscopyand leads to applications in the areas of astronomy, nuclear physics,environmental remediation, nuclear nonproliferation, and homelandsecurity. Producing the fine-pitched electrode segmentation oftenrequired for imaging has been problematic in the past. To address thisissue, we have developed an amorphous-semiconductor contact technology.Using this technology, fully passivated detectors with closely spacedcontacts can be produced using a simple fabrication process. The currentstate of the amorphous-semiconductor contact technology and thechallenges that remain will be given in this paper.
Date:
October 13, 2006
Creator:
Amman, Mark; Luke, Paul N. & Boggs, Steven E.
Object Type:
Article
System:
The UNT Digital Library
Remaining Sites Verification Package for the 128-F-3 PNL Burn Pit, Waste Site Reclassification Form 2006-042
The 128-F-3 waste site is a former burn pit associated with the 100-F Area experimental animal farm. The site was overlain by coal ash associated with the 126-F-1 waste site and could not be located during confirmatory site evaluation. Therefore, a housekeeping action was performed to remove the coal ash potentially obscuring residual burn pit features. The results of verification sampling demonstrated that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also showed that residual contaminant concentrations are protective of groundwater and the Columbia River.
Date:
October 20, 2006
Creator:
Dittmer, L. M.
Object Type:
Report
System:
The UNT Digital Library
Structure of incommensurate gold sulfide monolayer on Au(111)
Two-dimensional confined systems, such as substrate-supported incommensurate layers, are of interest because their structural and electronic properties may differ from those of bulk materials. While advances in experimental techniques have resulted in the growth of many such interesting systems, progress can often be hampered by the lack of an atomistic-scale understanding of the structure, especially for incommensurate systems. In this work, we develop an atomic-scale model for an ordered incommensurate gold-sulfide (AuS) adlayer that has been previously demonstrated to exist on the Au(111) surface, following sulfur deposition and annealing to 450 K. We introduce theoretical techniques within density functional theory to take into account charge transfer in an incommensurate system and model scanning tunneling microscopy images, which are in good agreement with experiment. Our simulations indicate that this model is remarkably robust. We analyze the nature of bonding in this structure using state-of-the-art Wannier-function based techniques. Our analysis provides a natural explanation for the extraordinary robustness and unusual stoichiometry of this layer. This structure and its chemistry have implications for related S-Au interfaces, such as those in self-assembled monolayers of thiols on Au substrates.
Date:
October 4, 2006
Creator:
Quek, S Y; Biener, M M; Biener, J; Bhattacharjee, J; Friend, C M; Waghmare, U V et al.
Object Type:
Article
System:
The UNT Digital Library
Power Corrections in Charmless Nonleptonic B Decays: Annihilationis Factorizable and Real
We classify {Lambda}{sub QCD}/m{sub b} power corrections to nonleptonic B {yields} M{sub 1}M{sub 2} decays, where M{sub 1,2} are charmless non-isosinglet mesons. Using recent developments in soft-collinear effective theory, we prove that the leading contributions to annihilation amplitudes of order {alpha}{sub s}(m{sub b}) {Lambda}{sub QCD}/m{sub b} are real. The leading annihilation amplitudes depend on twist-2 and the twist-3 three parton distributions. A complex nonperturbative parameter from annihilation first appears at {Omega}[{alpha}{sub s}{sup 2}({radical}{Lambda}m{sub b}){Lambda}{sub QCD}/m{sub b}]. 'Chirally enhanced' contributions are also factorizable and real at lowest order. Thus, incalculable strong phases are suppressed in annihilation amplitudes, unless the {alpha}{sub s}({radical}{Lambda}m{sub b}) expansion breaks down. Modeling the distribution functions, we find that (11 {+-} 9)% and (15 {+-} 11)% of the absolute values of the measured {bar B}{sup 0} {yields} K{sup -}{pi}{sup +} and B{sup -} {yields} K{sup -}K{sup 0} penguin amplitudes come from annihilation. This is consistent with the expected size of power corrections.
Date:
October 10, 2006
Creator:
Arnesen, Christian M.; Ligeti, Zoltan; Rothstein, Ira Z. & Stewart, Iain W.
Object Type:
Article
System:
The UNT Digital Library
The Development of New User Research Capabilities in Environmental Molecular Science: Workshop Report
On August 1, and 2, 2006, 104 scientists representing 40 institutions including 24 Universities and 5 National Laboratories gathered at the W.R. Wiley Environmental Molecular Sciences Laboratory, a National scientific user facility, to outline important science challenges for the next decade and identify major capabilities needed to pursue advanced research in the environmental molecular sciences. EMSL’s four science themes served as the framework for the workshop. The four science themes are 1) Biological Interactions and Interfaces, 2) Geochemistry/Biogeochemistry and Surface Science, 3) Atmospheric Aerosol Chemistry, and 4) Science of Interfacial Phenomena.
Date:
October 31, 2006
Creator:
Felmy, Andrew R.; Baer, Donald R.; Fredrickson, Jim K.; Gephart, Roy E. & Rosso, Kevin M.
Object Type:
Report
System:
The UNT Digital Library
Shillapoo Wildlife Area, Annual Report 2006-2007.
This report summarizes accomplishments, challenges and successes on WDFW's Shillapoo Wildlife Area funded under Bonneville Power Administration's (BPA) Wildlife Mitigation Program (BPA project No.2003-012-00) during the Fiscal Year 07 contract period October 1, 2006-September 30, 2007. The information presented here is intended to supplement that contained in BPA's PISCES contract development and reporting system. The organization below is by broad categories of work but references are made to individual work elements in the PISCES Statement of Work as appropriate. The greatest success realized during this contract period was significant positive changes in the vegetative community in several wetland basins throughout the wildlife area. This major goal is being achieved in part by new equipment and operation capability funded under the BPA contract, state capital and migratory bird stamp funds, and the past or ongoing investment of other partners including Ducks Unlimited, The Natural Resources Conservation Service (NRCS), Clark Public Utilities and others. We continue to be challenged by requirements under the archaeological and historic preservation act necessary to protect many sensitive sites known to occur within the wildlife area. The problems encountered to date have been largely administrative in nature and those experienced this year were unforeseen and probably unavoidable. …
Date:
October 1, 2006
Creator:
Calkins, Brian
Object Type:
Report
System:
The UNT Digital Library
Mitochondrial Avid Radioprobes. Preparation and Evaluation of7'(Z)-[125I]Iodorotenone and 7'(Z)-[125I]Iodorotenol
None
Date:
October 18, 2006
Creator:
VanBrocklin, Henry F.; Hanrahan, Stephen M.; Enas, Joel D.; Nandanan, Erathodiyil & O'Neil, James P.
Object Type:
Article
System:
The UNT Digital Library