The 1997/98 El Nino: A Test for Climate Models (open access)

The 1997/98 El Nino: A Test for Climate Models

Version 3 of the Hadley Centre Atmospheric Model (HadAM3) has been used to demonstrate one means of comparing a general circulation model with observations for a specific climate perturbation, namely the strong 1997/98 El Nino. This event was characterized by the collapse of the tropical Pacific's Walker circulation, caused by the lack of a zonal sea surface temperature gradient during the El Nino. Relative to normal years, cloud altitudes were lower in the western portion of the Pacific and higher in the eastern portion. HadAM3 likewise produced the observed collapse of the Walker circulation, and it did a reasonable job of reproducing the west/east cloud structure changes. This illustrates that the 1997/98 El Nino serves as a useful means of testing cloud-climate interactions in climate models.
Date: March 5, 2004
Creator: Lu, R; Dong, B; Cess, R D & Potter, G L
Object Type: Article
System: The UNT Digital Library
Ab Initio Studies of Coke Formation on Ni Catalysts During Methane Reforming (open access)

Ab Initio Studies of Coke Formation on Ni Catalysts During Methane Reforming

The atomic-scale processes that control the formation of carbon deposits on Ni catalysts in reforming applications are poorly understood. Ab initio Density Functional Theory calculations have been used to examine several key elementary steps in the complex network of chemical reactions that precedes carbon formation on practical catalysts. Attention has been focused on the disproportionation of CO. A comparative study of this reaction on flat and stepped crystal planes of Ni has provided the first direct evidence that surface carbon formation is driven by elementary reactions occurring at defect sites on Ni catalysts. The adsorption and diffusion of atomic H on several flat and stepped Ni surfaces has also been characterized experimentally.
Date: March 5, 2006
Creator: Sholl, David S.
Object Type: Report
System: The UNT Digital Library
Aberration correction for analytical in situ TEM - the NTEAM concept. (open access)

Aberration correction for analytical in situ TEM - the NTEAM concept.

Future aberration corrected transmission electron microscopes (TEM) will have a strong impact in materials science, since such microscopes yield information on chemical bonding and structure of interfaces, grain boundaries and lattice defects at an atomic level. Beyond this aberration correction offers new possibilities for in situ experiments performed under controlled temperature, magnetic field, strain etc. at atomic resolution. Such investigations are necessary for solving problems arising from electronic component miniaturization, for example. Significant progress can be expected by means of analytical aberration corrected TEM. These next generation microscopes will be equipped with an aberration corrected imaging system, a monochromator and aberration corrected energy filters. These novel elements have already been designed and partially realized [1,2,3].
Date: March 5, 2002
Creator: Kabius, B.; Allen, C. W. & Miller, D. J.
Object Type: Article
System: The UNT Digital Library
Actinic Mask Inspection at the ALS Initial Design Review (open access)

Actinic Mask Inspection at the ALS Initial Design Review

This report is the first milestone report for the actinic mask blank inspection project conducted at the VNL, which forms sub-section 3 of the Q1 2003 mask blank technology transfer program at the VNL. Specifically this report addresses deliverable 3.1.1--design review and preliminary tool design. The goal of this project is to design an actinic mask inspection tool capable of operating in two modes: high-speed scanning for the detection of multilayer defects (inspection mode), and a high-resolution aerial image mode in which the image emulates the imaging illumination conditions of a stepper system (aerial image or AIM mode). The purpose and objective of these two modes is as follows: (1) Defect inspection mode--This imaging mode is designed to scan large areas of the mask for defects EUV multilayer coatings. The goal is to detect the presence of multilayer defects on a mask blank and to store the co-ordinates for subsequent review in AIM mode, thus it is not essential that the illumination and imaging conditions match that of a production stepper. Potential uses for this imaging mode include: (a) Correlating the results obtained using actinic inspection with results obtained using other non-EUV defect inspection systems to verify that the non-EUV …
Date: March 5, 2003
Creator: Barty, A.; Chapman, H.; Sweeney, D.; Levesque, R.; Bokor, J.; Gullikson, E. et al.
Object Type: Report
System: The UNT Digital Library
Advanced Combustion (open access)

Advanced Combustion

Topics covered in this presentation include: the continued importance of coal; related materials challenges; combining oxy-combustion & A-USC steam; and casting large superalloy turbine components.
Date: March 5, 2013
Creator: Holcomb, Gordon R.
Object Type: Article
System: The UNT Digital Library
Advanced hardware and software methods for thread and gear dimensional metrology. CRADA final report (open access)

Advanced hardware and software methods for thread and gear dimensional metrology. CRADA final report

The Oak Ridge Centers for Manufacturing Technology (ORCMT) and Apeiron Incorporated have collaborated on an effort to develop a frequency modulated continuous wave (FMCW) fiber lidar system for dimensional metrology of internal threads, gears, and splines. The purpose of this effort was to assist a small company in developing an instrument that would exceed the performance of competing foreign instruments and provide measurement capabilities necessary to assure compliance for NASA facilities and other industrial facilities. The two parties collaborated on design, assembly, and bench testing of the prototype instrument. The prototype system was targeted to have the capability of profiling internally machined gears and threads to an accuracy of less than a micron.
Date: March 5, 1997
Creator: Miller, A. C., Jr. & Grann, E. B.
Object Type: Report
System: The UNT Digital Library
Advanced power conversion based on the Aerocapacitor{trademark}. Final report (open access)

Advanced power conversion based on the Aerocapacitor{trademark}. Final report

This report summarizes work performed under contract No. DE-FC07-94ID13283, {open_quotes}Advanced Power Conversion Based on the Aerocapacitors{trademark}.{close_quotes} Under this contract high power density, high energy density, organic electrolyte Aerocapacitors{trademark} were developed and characterized for power conversion applications. Pilot facilities for manufacturing prototype AA-size Aerocapacitors{trademark} were put in place. The low ESR and good frequency response of these devices show that they are ideal components for high discharge rate and low to moderate frequency (< 10 kHz) applications such as power conversion.
Date: March 5, 1997
Creator: Roark, D.
Object Type: Report
System: The UNT Digital Library
Advances in processing of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconductors. (open access)

Advances in processing of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconductors.

Advances in the processing and fabrication of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) high-T{sub c} superconductors by the powder-in-tube technique continue to bring this material closer to commercial applications. Enhancement of the transport critical current density (J{sub c}) of Ag-sheathed Bi-2223 tapes was achieved by increasing the packing density of the precursor powder, improving mechanical deformation, and adjusting the cooling rate. Long lengths (&gt;150 m) of multifilamentary Bi-2223 tapes have been fabricated and carry critical currents (I{sub c}) of &gt;50 A (J{sub c} {approx} 25 kA/cm{sup 2}) at 77 K in self-field. A 1260-m-long tape carried an I{sub c} of 18 A (J{sub c} {approx} 12 kA/cm{sup 2}) from end-to-end. Several prototype coils have been assembled from these long-length tapes. Recent progress in the fabrication of Bi-2223 tapes is presented in this paper.
Date: March 5, 1998
Creator: Balachandran, U.; Eror, N. G.; Haldar, P. & Lelovic, M.
Object Type: Article
System: The UNT Digital Library
Allinea DDT as a Parallel Debugging Alternative to Totalview (open access)

Allinea DDT as a Parallel Debugging Alternative to Totalview

Totalview, from the Etnus Corporation, is a sophisticated and feature rich software debugger for parallel applications. As Totalview has gained in popularity and market share its pricing model has increased to the point where it is often prohibitively expensive for massively parallel supercomputers. Additionally, many of Totalview's advanced features are not used by members of the scientific computing community. For these reasons, supercomputing centers have begun to search for a basic parallel debugging tool which can be used as an alternative to Totalview. As the cost and complexity of Totalview has increased over the years, scientific computing centers have started searching for a viable parallel debugging alternative. DDT (Distributed Debugging Tool) from Allinea Software is a relatively new parallel debugging tool which aims to provide much of the same functionality as Totalview. This review outlines the basic features and limitations of DDT to determine if it can be a reasonable substitute for Totalview. DDT was tested on the NERSC platforms Bassi, Seaborg, Jacquard and Davinci with Fortran90, C, and C++ codes using MPI and OpenMP for parallelism.
Date: March 5, 2007
Creator: Antypas, K.B.
Object Type: Report
System: The UNT Digital Library
Analysis of Geomechanical Behavior for the Drift Scale Test (open access)

Analysis of Geomechanical Behavior for the Drift Scale Test

The Drift Scale Test (DST) now underway at Yucca Mountain has been simulated using a Drift Scale Distinct Element (DSDE) model. Simulated deformations show good agreement with field deformation measurements. Results indicate most fracture deformation is located above the crown of the Heated Drift. This work is part of the model validation effort for the DSDE model, which is used to assess thermal-mechanical effects on the hydrology of the rock mass surrounding a potential repository.
Date: March 5, 2001
Creator: Blair, S.C.; Carlson, S.R. & Wagoner, J.L.
Object Type: Article
System: The UNT Digital Library
Analysis of Geomechanical Behavior for the Drift Scale Test (open access)

Analysis of Geomechanical Behavior for the Drift Scale Test

The Drift Scale Test (DST) now underway at Yucca Mountain has been simulated using a Drift Scale Distinct Element (DSDE) model. Simulated deformations show good agreement with field deformation measurements. Results indicate most fracture deformation is located above the crown of the Heated Drift. This work is part of the model validation effort for the DSDE model, which is used to assess thermal-mechanical effects on the hydrology of the rock mass surrounding a potential repository.
Date: March 5, 2001
Creator: Blair, S. C.; Carlson, S. R. & Wagoner, J. L.
Object Type: Article
System: The UNT Digital Library
Annual Report: Carbon Capture Simulation Initiative (CCSI) (30 September 2013) (open access)

Annual Report: Carbon Capture Simulation Initiative (CCSI) (30 September 2013)

The Carbon Capture Simulation Initiative (CCSI) is a partnership among national laboratories, industry and academic institutions that is developing and deploying state-of-the-art computational modeling and simulation tools to accelerate the commercialization of carbon capture technologies from discovery to development, demonstration, and ultimately the widespread deployment to hundreds of power plants. The CCSI Toolset will provide end users in industry with a comprehensive, integrated suite of scientifically validated models, with uncertainty quantification (UQ), optimization, risk analysis and decision making capabilities. The CCSI Toolset incorporates commercial and open-source software currently in use by industry and is also developing new software tools as necessary to fill technology gaps identified during execution of the project. Ultimately, the CCSI Toolset will (1) enable promising concepts to be more quickly identified through rapid computational screening of devices and processes; (2) reduce the time to design and troubleshoot new devices and processes; (3) quantify the technical risk in taking technology from laboratory-scale to commercial-scale; and (4) stabilize deployment costs more quickly by replacing some of the physical operational tests with virtual power plant simulations. CCSI is led by the National Energy Technology Laboratory (NETL) and leverages the Department of Energy (DOE) national laboratories’ core strengths in modeling …
Date: March 5, 2014
Creator: Miller, David C.; Syamlal, Madhava; Cottrell, Roger; Kress, Joel D.; Sundaresan, S.; Sun, Xin et al.
Object Type: Report
System: The UNT Digital Library
Applicability of flat plate methods in determining fluid/structure interaction effects in BWR pressure suppression systems (open access)

Applicability of flat plate methods in determining fluid/structure interaction effects in BWR pressure suppression systems

Flat plate chord tests are one experimental method used to investigate how fluid/structure interaction (FSI) effects modify the impulsive loading in nuclear reactor pressure suppression pools. This analytical study examines the applicability of using a flexible flat plate in an otherwise rigid shell to model dynamic pool wall response in a flexible shell pressure suppression torus. Bubble pressures varying by a factor of seven are used as input to two-dimensional finite-element models. Boundary response to various plate and shell thicknesses are compared on the basis of equivalent natural frequency. Results indicate the qualitative flat plate response compares well with the flexible shell but absolute pressures vary significantly and nonconservatively.
Date: March 5, 1979
Creator: Holman, G.S.; McCauley, E.W. & Lu, S.C.H.
Object Type: Article
System: The UNT Digital Library
Application of non-radiometric methods to the determination of plutonium. Literature review conducted for the Buried Waste Integrated Program (open access)

Application of non-radiometric methods to the determination of plutonium. Literature review conducted for the Buried Waste Integrated Program

This literature review was motivated by discussions that took place during a review of contamination control technologies proposed for INEL (buried waste). It should be a useful tool in identifying non-radiation measurement techniques for Pu and Am such as ICP-MS, which should fulfill the following criteria: apparatus must be field deployable; up to 100 samples per day; and lower levels of detection and required time must be listed. The sensitivity of ICP and RIMS is compared against that needed for contamination monitoring at INEL. Only Pu-241, with a required detection limit of 400 ppt, would challenge the sensitivity of ICP-MS; Pu-238 would be easily determined. The need to determine Pu-238 and Am-241 in the presence of U-238 and Pu-241 seems to preclude the possibility of using laser ablation ICP-MS for Pu monitoring. ICP-AES and -LEAFS methods may not have enough sensitivity to determine Pu-238 at 2 ppb level with confidence, but RIMS (resonance ionization mass spectroscopy) should be adequate. 47 refs, figs.
Date: March 5, 1992
Creator: Edelson, M. C.
Object Type: Report
System: The UNT Digital Library
APPLICATION OF STIR BAR SORPTIVE EXTRACTION TO ANALYSIS OF VOLATILE AND SEMIVOLATILE ORGANIC CHEMICALS OF POTENTIAL CONCERN IN SOLIDS AND AQUEOUS SAMPLES FROM THE HANFORD SITE (open access)

APPLICATION OF STIR BAR SORPTIVE EXTRACTION TO ANALYSIS OF VOLATILE AND SEMIVOLATILE ORGANIC CHEMICALS OF POTENTIAL CONCERN IN SOLIDS AND AQUEOUS SAMPLES FROM THE HANFORD SITE

Stir bar sorptive extraction was applied to aqueous and solid samples for the extraction and analysis of organic compounds from the Hanford chemicals of potential concern list, as identified in the vapor data quality objectives. The 222-S Laboratory analyzed these compounds from vapor samples on thermal desorption tubes as part of the Hanford Site industrial hygiene vapor sampling effort.
Date: March 5, 2009
Creator: JM, FRYE & JM, KUNKEL
Object Type: Report
System: The UNT Digital Library
Applying Loop Optimizations to Object-oriented Abstractions Through General Classification of Array Semantics (open access)

Applying Loop Optimizations to Object-oriented Abstractions Through General Classification of Array Semantics

Optimizing compilers have a long history of applying loop transformations to C and Fortran scientific applications. However, such optimizations are rare in compilers for object-oriented languages such as C++ or Java, where loops operating on user-defined types are left unoptimized due to their unknown semantics. Our goal is to reduce the performance penalty of using high-level object-oriented abstractions. We propose an approach that allows the explicit communication between programmers and compilers. We have extended the traditional Fortran loop optimizations with an open interface. Through this interface, we have developed techniques to automatically recognize and optimize user-defined array abstractions. In addition, we have developed an adapted constant-propagation algorithm to automatically propagate properties of abstractions. We have implemented these techniques in a C++ source-to-source translator and have applied them to optimize several kernels written using an array-class library. Our experimental results show that using our approach, applications using high-level abstractions can achieve comparable, and in cases superior, performance to that achieved by efficient low-level hand-written codes.
Date: March 5, 2004
Creator: Yi, Q & Quinlan, D
Object Type: Article
System: The UNT Digital Library
ARM tropical pacific experiment (ATPEX): Role of cloud, water vapor and convection feedbacks in the coupled ocean/atmosphere system (open access)

ARM tropical pacific experiment (ATPEX): Role of cloud, water vapor and convection feedbacks in the coupled ocean/atmosphere system

We have initiated studies that include radiation model validation, improved treatment of the three-dimensional structure of cloud-radiation interactions, and sensitivity runs that will unravel the role of cloud-convection-radiation interactions in the Pacific Sear Surface Temperatures and the overlying Walker and Hadley circulation. The research program is divided into three phases: (1) radiation, (2) cloud parameterization issues; (3) feedback and ocean-atmosphere interactions.
Date: March 5, 1992
Creator: Ramanathan, V. & Barnett, T.P.
Object Type: Report
System: The UNT Digital Library
ARM tropical pacific experiment (ATPEX): Role of cloud, water vapor and convection feedbacks in the coupled ocean/atmosphere system. Progress report, September 1, 1991--August 31, 1992 (open access)

ARM tropical pacific experiment (ATPEX): Role of cloud, water vapor and convection feedbacks in the coupled ocean/atmosphere system. Progress report, September 1, 1991--August 31, 1992

We have initiated studies that include radiation model validation, improved treatment of the three-dimensional structure of cloud-radiation interactions, and sensitivity runs that will unravel the role of cloud-convection-radiation interactions in the Pacific Sear Surface Temperatures and the overlying Walker and Hadley circulation. The research program is divided into three phases: (1) radiation, (2) cloud parameterization issues; (3) feedback and ocean-atmosphere interactions.
Date: March 5, 1992
Creator: Ramanathan, V. & Barnett, T. P.
Object Type: Report
System: The UNT Digital Library
Assessing mixtures risks for cleanup and stewardship. (open access)

Assessing mixtures risks for cleanup and stewardship.

The U.S. Department of Energy (DOE) is responsible for addressing contamination from past research, production, and disposal activities at over 100 sites and facilities across the country. Use of emerging science to assess risks for these facilities is the key to defining appropriate solutions. Safely managing contamination is a priority to protect workers in the near term, and sustained protection is a priority for local communities over the long term. The Department conducts its environmental management program with input from a number of groups who have expressed concern about the safety of DOE sites over time and the possible conversion of some lands to other uses. In general, past facility activities and disposal operations have contaminated about 10% of the total collective area of DOE sites while surrounding lands have served as buffer zones. Portions of several sites have been released for other uses, such as wildlife preserves. Soil, surface water, and groundwater have been contaminated in most instances, and on-site waste disposal is targeted for many sites. Wastes and contamination that will remain in the environment are at the heart of ongoing future use and long-term management deliberations. For this reason, oversight groups and local citizens are scrutinizing the …
Date: March 5, 2002
Creator: MacDonell, M. M. & Hertzberg, R.
Object Type: Article
System: The UNT Digital Library
Assessing the Effect of Timing of Availability for Carbon Dioxide Storage in the Largest Oil and Gas Pools in the Alberta Basin: Description of Data and Methodology (open access)

Assessing the Effect of Timing of Availability for Carbon Dioxide Storage in the Largest Oil and Gas Pools in the Alberta Basin: Description of Data and Methodology

Carbon dioxide capture from large stationary sources and storage in geological media is a technologically-feasible mitigation measure for the reduction of anthropogenic emissions of CO2 to the atmosphere in response to climate change. Carbon dioxide (CO2) can be sequestered underground in oil and gas reservoirs, in deep saline aquifers, in uneconomic coal beds and in salt caverns. The Alberta Basin provides a very large capacity for CO2 storage in oil and gas reservoirs, along with significant capacity in deep saline formations and possible unmineable coal beds. Regional assessments of potential geological CO2 storage capacity have largely focused so far on estimating the total capacity that might be available within each type of reservoir. While deep saline formations are effectively able to accept CO2 immediately, the storage potential of other classes of candidate storage reservoirs, primarily oil and gas fields, is not fully available at present time. Capacity estimates to date have largely overlooked rates of depletion in these types of storage reservoirs and typically report the total estimated storage capacity that will be available upon depletion. However, CO2 storage will not (and cannot economically) begin until the recoverable oil and gas have been produced via traditional means. This report describes …
Date: March 5, 2007
Creator: Dahowski, Robert T. & Bachu, Stefan
Object Type: Report
System: The UNT Digital Library
Assessment of Physical Properties of Transuranic Waste in Hanford Single-Shell Tanks (open access)

Assessment of Physical Properties of Transuranic Waste in Hanford Single-Shell Tanks

CH2M HILL Hanford Group, Inc. (CH2M HILL) is in the process of identifying and developing supplemental process technologies to accelerate the tank waste cleanup mission. One technology targets disposal of Hanford transuranic (TRU) process wastes stored in single-shell tanks (SSTs). Ten Hanford SSTs are candidates for designation as contact-handled TRU waste type: the B-200 series tanks (241-B-201, -B-202, -B-203, and -B-204), the T-200 series tanks (241-T-201, -T-202, -T-203, and -T-204), and Tanks 241-T-110 and T-111. Current plans identify a process in which these wastes are retrieved from the tanks, either dry or with a recycled liquid stream to help mobilize the waste in the tank and through transfer lines and vessels, dewatered to remove excess liquid, and transferred to waste packages in a form suitable for disposal. CH2M HILL seeks to procure a process for dewatering, handling, and packaging the contact-handled TRU waste after it is retrieved. An understanding of waste physical properties is needed to support design of the SST TRU handling and packaging system and to produce suitable physical simulants to test such a process. Pacific Northwest National Laboratory (PNNL) has been tasked with developing these waste simulants. This report summarizes PNNL's assessment of available waste physical property …
Date: March 5, 2003
Creator: Rassat, Scot D.; Mahoney, Lenna A.; Wells, Beric E.; Mendoza, Donaldo P. & Caldwell, Dustin D.
Object Type: Report
System: The UNT Digital Library
Authorization basis supporting documentation for plutonium finishing plant (open access)

Authorization basis supporting documentation for plutonium finishing plant

The identification and definition of the authorization basis for the Plutonium Finishing Plant (PFP) facility and operations are essential for compliance to DOE Order 5480.21, Unreviewed Safety Questions. The authorization basis, as defined in the Order, consists of those aspects of the facility design basis, i.e., the structures, systems and components (SSCS) and the operational requirements that are considered to be important to the safety of operations and are relied upon by DOE to authorize operation of the facility. These facility design features and their function in various accident scenarios are described in WHC-SD-CP-SAR-021, Plutonium Finishing Plant Final Safety Analysis Report (FSAR), Chapter 9, `Accident Analysis.` Figure 1 depicts the relationship of the Authorization Basis to its components and other information contained in safety documentation supporting the Authorization Basis. The PFP SSCs that are important to safety, collectively referred to as the `Safety Envelope` are discussed in various chapters of the FSAR and in WHC-SD-CP-OSR-010, Plutonium Finishing Plant Operational Safety Requirements. Other documents such as Criticality Safety Evaluation Reports (CSERS) address and support some portions of the Authorization Basis and Safety Envelope.
Date: March 5, 1997
Creator: King, J.P., Fluor Daniel Hanford
Object Type: Report
System: The UNT Digital Library
Basin Analysis of the Mississippi Interior Salt Basin and Petroleum System Modeling of the Jurassic Smackover Formation, Eastern Gulf Coastal Plain, Final Report and Topical Reports 5-8 on Smackover Petroleum system and Underdevelopment Reservoirs (open access)

Basin Analysis of the Mississippi Interior Salt Basin and Petroleum System Modeling of the Jurassic Smackover Formation, Eastern Gulf Coastal Plain, Final Report and Topical Reports 5-8 on Smackover Petroleum system and Underdevelopment Reservoirs

The Smackover Formation, a major hydrocarbon-producing horizon in the Mississippi Interior Salt Basin (MISB), conformably overlies the Norphlet Formation and is conformably overlain by the Buckner Anhydrite Member of the Haynesville Formation. The Norphlet-Smackover contact can be either gradational or abrupt. The thickness and lithofacies distribution of the Smackover Formation were controlled by the configuration of incipient paleotopography. The Smackover Formation has been subdivided into three informal members, referred to as the lower, middle and upper members.
Date: March 5, 2002
Creator: Mancini, Ernest A.; Puckett, T. Markham; Parcell, William C.; Llinas, Juan Carlos; Kopaska-Merkel, David C. & Townsend, Roger N.
Object Type: Report
System: The UNT Digital Library
Beam tests of phosphorescent screens (open access)

Beam tests of phosphorescent screens

Twelve phosphorescent screens were beam tested for linearity, uniformity, low radiation damage and a suitable emitted wavelength for use with television cameras. One screen was chosen for the construction of several intercepting profile monitors which were used during the SLC Ten Sector Tests to measure the emittance and wakefield effects of a damped electron beam.
Date: March 5, 1985
Creator: Seeman, J. T.; Luth, V.; Ross, M. & Sheppard, J.
Object Type: Report
System: The UNT Digital Library