Search Results

Many-body Interactions in Magnetic Films and Nanostructures

Description: We describe results supported by DOE grant DE-FG02-04ER46158, which focused on magnetic interaction at surfaces, in thin films, and in metallic nanostructures. We report on three general topics: 1) The Rashba spin splitting at magnetic surfaces of rare earth metals, 2) magnetic nanowires self-assembled on stepped tungsten single crystals, and 3) magnetic interaction in graphene films doped with hydrogen atoms.
Date: December 12, 2012
Creator: Kevan, Stephen D.
Partner: UNT Libraries Government Documents Department

MOGO: Model-Oriented Global Optimization of Petascale Applications

Description: The MOGO project was initiated under in 2008 under the DOE Program Announcement for Software Development Tools for Improved Ease-of-Use on Petascale systems (LAB 08-19). The MOGO team consisted of Oak Ridge National Lab, Argonne National Lab, and the University of Oregon. The overall goal of MOGO was to attack petascale performance analysis by developing a general framework where empirical performance data could be efficiently and accurately compared with performance expectations at various levels of abstraction. This information could then be used to automatically identify and remediate performance problems. MOGO was be based on performance models derived from application knowledge, performance experiments, and symbolic analysis. MOGO was able to make reasonable impact on existing DOE applications and systems. New tools and techniques were developed, which, in turn, were used on important DOE applications on DOE LCF systems to show significant performance improvements.
Date: September 14, 2012
Creator: Malony, Allen D. & Shende, Sameer S.
Partner: UNT Libraries Government Documents Department

Genetic Analysis of Chloroplast Translation

Description: The assembly of the photosynthetic apparatus requires the concerted action of hundreds of genes distributed between the two physically separate genomes in the nucleus and chloroplast. Nuclear genes coordinate this process by controlling the expression of chloroplast genes in response to developmental and environmental cues. However, few regulatory factors have been identified. We used mutant phenotypes to identify nuclear genes in maize that modulate chloroplast translation, a key control point in chloroplast gene expression. This project focused on the nuclear gene crp1, required for the translation of two chloroplast mRNAs. CRP1 is related to fungal proteins involved in the translation of mitochondrial mRNAs, and is the founding member of a large gene family in plants, with {approx}450 members. Members of the CRP1 family are defined by a repeated 35 amino acid motif called a ''PPR'' motif. The PPR motif is closely related to the TPR motif, which mediates protein-protein interactions. We and others have speculated that PPR tracts adopt a structure similar to that of TPR tracts, but with a substrate binding surface adapted to bind RNA instead of protein. To understand how CRP1 influences the translation of specific chloroplast mRNAs, we sought proteins that interact with CRP1, and identified the RNAs associated with CRP1 in vivo. We showed that CRP1 is associated in vivo with the mRNAs whose translation it activates. To explore the functions of PPR proteins more generally, we sought mutations in other PPR-encoding genes: mutations in the maize PPR2 and PPR4 were shown to disrupt chloroplast ribosome biogenesis and chloroplast trans-splicing, respectively. These and other results suggest that the nuclear-encoded PPR family plays a major role in modulating the expression of the chloroplast genome in higher plants.
Date: August 15, 2005
Creator: Barkan, Alice
Partner: UNT Libraries Government Documents Department


Description: Spectra and internal dynamics of highly excited molecules are essential to understanding processes of fundamental importance for combustion, including intramolecular energy transfer and isomerization reactions. The goal of our program is to develop new theoretical tools to unravel information about intramolecular dynamics encoded in highly excited experimental spectra. We want to understand the formations of ''new vibrational modes'' when the ordinary normal modes picture breaks down in highly excited vibrations. We use bifurcation analysis of semiclassical versions of the effective Hamiltonians used by spectroscopists to fit complex experimental spectra. Specific molecular systems are of interest for their relevance to combustion and the availability of high-quality experimental data. Because of its immense importance in combustion, the isomerizing acetylene/vinylidene system has been the object of long-standing experimental and theoretical research. We have made significant progress in systematically understanding the bending dynamics of the acetylene system. We have begun to make progress on extending our methodology to the full bend-stretch vibrational degrees of freedom, including dynamics with multiple wells and above barrier motion, and time-dependent dynamics. For this, development of our previous methods using spectroscopic fitting Hamiltonians is needed, for example, for systems with multiple barriers.
Date: June 17, 2005
Creator: Kellman, Michael E.
Partner: UNT Libraries Government Documents Department

Bibliographical Control of Afro-American Literature, Volume 1: Papers Presented at a Conference

Description: These papers are a compilation presented at a conference on bibliographic control of Afro-American literature. The papers discuss issues in cataloging and archiving African-American literature including relevant subject headings, sources of texts, and collection development. Index starts on page 293.
Date: 1976
Creator: Totten, Herman L.
Partner: UNT College of Information

Bibliographical Control of Afro-American Literature, Volume 3: Evaluation of the Conference

Description: These papers offer discussions and conclusions regarding a conference on bibliographic control of Afro-American literature. The text includes a summary of the reasons for the conference, a report from a conference evaluator, and evaluation forms, as well as minutes and letters regarding the proceedings.
Date: 1976
Creator: Totten, Herman L. & Bullock, Penelope L.
Partner: UNT College of Information

Extreme Performance Scalable Operating Systems Final Progress Report (July 1, 2008 - October 31, 2011)

Description: This is the final progress report for the FastOS (Phase 2) (FastOS-2) project with Argonne National Laboratory and the University of Oregon (UO). The project started at UO on July 1, 2008 and ran until April 30, 2010, at which time a six-month no-cost extension began. The FastOS-2 work at UO delivered excellent results in all research work areas: * scalable parallel monitoring * kernel-level performance measurement * parallel I/0 system measurement * large-scale and hybrid application performance measurement * onlne scalable performance data reduction and analysis * binary instrumentation
Date: October 31, 2011
Creator: Malony, Allen D. & Shende, Sameer
Partner: UNT Libraries Government Documents Department


Description: A five year solar radiation database derived from satellite cloud cover and auxiliary data has been created for the Pacific Northwest. The database provides hourly global, beam, and diffuse irradiance values from 1998 through 2002 from longitude -110.05{sup o} to -125.05{sup o} and north latitude 42.05{sup o} to 49.05{sup o} on a 0.1{sup o} grid. This final report describes how the database was created, the characteristics of the database, the software tool developed to facilitate the use of the database, and dissemination of the database.
Date: March 29, 2004
Creator: Vignola, Frank & Perez, Richard
Partner: UNT Libraries Government Documents Department

Performance Engineering Technology for Scientific Component Software

Description: Large-scale, complex scientific applications are beginning to benefit from the use of component software design methodology and technology for software development. Integral to the success of component-based applications is the ability to achieve high-performing code solutions through the use of performance engineering tools for both intra-component and inter-component analysis and optimization. Our work on this project aimed to develop performance engineering technology for scientific component software in association with the DOE CCTTSS SciDAC project (active during the contract period) and the broader Common Component Architecture (CCA) community. Our specific implementation objectives were to extend the TAU performance system and Program Database Toolkit (PDT) to support performance instrumentation, measurement, and analysis of CCA components and frameworks, and to develop performance measurement and monitoring infrastructure that could be integrated in CCA applications. These objectives have been met in the completion of all project milestones and in the transfer of the technology into the continuing CCA activities as part of the DOE TASCS SciDAC2 effort. In addition to these achievements, over the past three years, we have been an active member of the CCA Forum, attending all meetings and serving in several working groups, such as the CCA Toolkit working group, the CQoS working group, and the Tutorial working group. We have contributed significantly to CCA tutorials since SC'04, hosted two CCA meetings, participated in the annual ACTS workshops, and were co-authors on the recent CCA journal paper [24]. There are four main areas where our project has delivered results: component performance instrumentation and measurement, component performance modeling and optimization, performance database and data mining, and online performance monitoring. This final report outlines the achievements in these areas for the entire project period. The submitted progress reports for the first two years describe those year's achievements in detail. We discuss progress in the ...
Date: May 8, 2007
Creator: Malony, Allen D.
Partner: UNT Libraries Government Documents Department

Center for Technology for Advanced Scientific Component Software (TASCS)

Description: The UO portion of the larger TASCS project was focused on the usability subproject identified in the original project proposal. The key usability issue that we tacked was that of supporting legacy code developers in migrating to a component-oriented design pattern and development model with minimal manual labor. It was observed during the lifetime of the TASCS (and previous CCA efforts) that more often than not, users would arrive with existing code that was developed previous to their exposure to component design methods. As such, they were faced with the task of both learning the CCA toolchain and at the same time, manually deconstructing and reassembling their existing code to fit the design constraints imposed by components. This was a common complaint (and occasional reason for a user to abandon components altogether), so our task was to remove this manual labor as much as possible to lessen the burden placed on the end-user when adopting components for existing codes. To accomplish this, we created a source-based static analysis tool that used code annotations to drive code generation and transformation operations. The use of code annotations is due to one of the key technical challenges facing this work | programming languages are limited in the degree to which application-specific semantics can be represented in code. For example, data types are often ambiguous. The C pointer is the most common example cited in practice. Given a pointer to a location in memory, should it be interpreted as a singleton or an array. If it is to be interpreted as an array, how many dimensions does the array have? What are their extents? The annotation language that we designed and implemented addresses this ambiguity issue by allowing users to decorate their code in places where ambiguity exists in order to guide tools to ...
Date: June 30, 2010
Creator: Sottile, Dr. Mathew
Partner: UNT Libraries Government Documents Department

Emissions Of Greenhouse Gases From Rice Agriculture

Description: This project produced detailed data on the processes that affect methane and nitrous oxide emissions from rice agriculture and their inter-relationships. It defines the shifting roles and potential future of these gases in causing global warming and the benefits and tradeoffs of reducing emissions. The major results include: 1). Mechanisms and Processes Leading to Methane Emissions are Delineated. Our experiments have tested the standard model of methane emissions from rice fields and found new results on the processes that control the flux. A mathematical mass balance model was used to unravel the production, oxidation and transport of methane from rice. The results suggested that when large amounts of organic matter are applied, the additional flux that is observed is due to both greater production and reduced oxidation of methane. 2). Methane Emissions From China Have Been Decreasing Over the Last Two Decades. We have calculated that methane emissions from rice fields have been falling in recent decades. This decrease is particularly large in China. While some of this is due to reduced area of rice agriculture, the bigger effect is from the reduction in the emission factor which is the annual amount of methane emitted per hectare of rice. The two most important changes that cause this decreasing emission from China are the reduced use of organic amendments which have been replaced by commercial nitrogen fertilizers, and the increased practice of intermittent flooding as greater demands are placed on water resources. 3). Global Methane Emissions Have Been Constant For More Than 20 Years. While the concentrations of methane in the atmosphere have been leveling off in recent years, our studies show that this is caused by a near constant total global source of methane for the last 20 years or more. This is probably because as some anthropogenic sources have ...
Date: July 16, 2009
Creator: Khalil, M. Aslam K.
Partner: UNT Libraries Government Documents Department

Interpretation of Borehole Tides and Other Elastomechanical Oscillatory Phenomena in Geothermal Systems

Description: Ultralow to low-frequency oscillatory phenomena of elastomechanical nature have been observed in a number of geothermal areas. These include pressure and water level oscillations in the tidal frequency range 10{sup -6} to 10{sup -4} Hz (White, 1968), flow oscillations at around 10{sup -3} Hz (Bodvarsson and Bjornsson, 1976) and ground noise in the range 10{sup -1} to 10 Hz (Douze and Sorrel, 1972). The presence of such oscillations conveys certain information on the underlying geothermal systems which is of both theoretical and practical interest. In the following, we will very briefly discuss a few aspects relating to the interpretation of oscillatory field data with the main emphasis on borehole tides. 3 figs., 4 refs.
Date: December 14, 1977
Creator: Bodvarsson, Gunnar
Partner: UNT Libraries Government Documents Department

Development of Radon-222 as a Natural Tracer for Monitoring the Remediation of NAPL Contamination in the Subsurface.

Description: The objective of this research is to develop a unique method for using naturally occurring radon-222 as an inexpensive partitioning tracer for locating and quantitatifying nonaqueous phase liquid (NAPL) contamination in the subsurface, and assessing the effectiveness of NAPL remediation. Laboratory, field, and modeling studies are being performed to evaluate this technique, and to develop methods for its successful implementation in practice.
Date: June 1, 1999
Creator: Semprini, Lewis
Partner: UNT Libraries Government Documents Department

In Situ, Field Scale Evaluation of Surfactant Enhanced DNAPL Recovery Using a Single-Well, Push-Pull Test

Description: The overall goal of this project is to further develop the single-well, ''push-pull'' test method as a site characterization and feasibility assessment tool for studying the fundamental fate and transport behavior of injected surfactants and their ability to solubilize and mobilize DNAPLs in the subsurface. To address the three objectives, the research plan combines controlled intermediate-scale laboratory experiments in unique physical aquifer models with a parallel series of pilot-scale field experiments in existing monitoring wells at selected trichloroethylene (TCE) contaminated field sites.
Date: June 1, 1999
Creator: Istok, Jonathan D. & Field, Jennifer, A.
Partner: UNT Libraries Government Documents Department

Final Report: Design & Evaluation of Energy Efficient Modular Classroom Structures Phase II / Volume I-VII, January 17, 1995 - October 30, 1999

Description: We are developing innovations to enable modular builders to improve the energy performance of their classrooms with no increase in first cost. The Modern Building Systems' (MBS) classroom building conforms to the stringent Oregon energy code, and at $18/ft{sup 2} ($1.67/m{sup 2}) (FOB the factory) it is at the low end of the cost range for modular classrooms. We have investigated daylighting, cross-ventilation, solar preheat of ventilation air, air-to-air heat exchanger, electric lighting controls, and down-sizing HVAC systems as strategies to improve energy performance. We were able to improve energy performance with no increase in first cost in all climates examined. Two papers and a full report on Phase I of this study are available. The work described in this report is from the second phase of the project. In the first phase we redesigned the basic modular classroom to incorporate energy strategies including daylighting, cross-ventilation, solar preheating of ventilation air, and insulation. We also explored thermal mass but determined that it was not a cost-effective strategy in the five climates we examined. Energy savings ranged from 6% to 49% with an average of 23%. Paybacks ranged from 1.3 years to 23.8 years, an average of 12.1 years. In Phase II the number of baseline buildings was expanded by simulating buildings that would be typical of those produced by Modern Building Systems, Inc. (MBS) for each of the seven locations/climates. A number of parametric simulations were performed for each energy strategy. Additionally we refined our previous algorithm for a solar ventilation air wall preheater and developed an algorithm for a roof preheater configuration. These algorithms were coded as functions in DOE 2.1E. We were striving for occupant comfort as well as energy savings. We performed computer analyses to verify adequate illumination on vertical surfaces and acceptable glare levels when using ...
Date: October 30, 1999
Partner: UNT Libraries Government Documents Department

Architectural Design Criteria for F-Block Metal Ion Sequestering Agents

Description: The objective of this project is to provide the means to optimize ligand architecture for f-block metal recognition. Our strategy builds on an innovative and successful molecular modeling approach in developing polyether ligand design criteria for the alkali and alkaline earth cations. The hypothesis underlying this proposal is that differences in metal ion binding with multidentate ligands bearing the same number and type of donor groups are primarily attributable to intramolecular steric factors. We propose quantifying these steric factors through the application of molecular mechanics models. The proposed research involves close integration of theoretical and experimental chemistry. The experimental work entails synthesizing novel ligands and experimentally determining structures and binding constants for metal ion complexation by series of ligands in which architecture is systematically varied. The theoretical work entails using electronic structure calculations to parameterize a molecular mechanics force field for a range of metal ions and ligand types. The resulting molecular mechanics force field will be used to predict low energy structures for unidentate, bidentate, and multidentate ligands and their metal complexes through conformational searches. Results will be analyzed to assess the relative importance of several steric factors including optimal M-L length, optimal geometry at the metal center, optimal geometry at the donor atoms (complementarity), and conformation prior to binding (preorganization). An accurate set of criteria for the design of ligand architecture will be obtained from these results. These criteria will enable researchers to target ligand structures for synthesis and thereby dramatically reduce the time and cost associated with metal-specific ligand development.
Date: June 1, 1999
Creator: Hay, Benjamin P.; Roundhill, David M.; Paine Jr., Robert Treat; Raymond, Kenneth N.; Rogers, Robin D.; Hutchison, James E. et al.
Partner: UNT Libraries Government Documents Department