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Application of Stochastic Radiative Transfer Theory to the ARM Cloud-Radiative Parameterization Problem

Description: This project had two primary goals: (1) development of stochastic radiative transfer as a parameterization that could be employed in an AGCM environment, and (2) exploration of the stochastic approach as a means for representing shortwave radiative transfer through mixed-phase layer clouds. To achieve these goals, climatology of cloud properties was developed at the ARM CART sites, an analysis of the performance of the stochastic approach was performed, a simple stochastic cloud-radiation parameterization for an AGCM was developed and tested, a statistical description of Arctic mixed phase clouds was developed and the appropriateness of stochastic approach for representing radiative transfer through mixed-phase clouds was assessed. Significant progress has been made in all of these areas and is detailed in the final report.
Date: April 9, 2012
Creator: Veron, Dana E.
Partner: UNT Libraries Government Documents Department

New Switches for Utility-Scale Inverters: First In-Class Demonstration of a Completely New Type of SiC Bipolar Switch (15kV-20kV) for Utility-Scale Inverters

Description: Solar ADEPT Project: The SiCLAB is developing a new power switch for utility-scale PV inverters that would improve the performance and significantly reduce the size, weight, and energy loss of PV systems. A power switch controls the electrical energy flowing through an inverter, which takes the electrical current from a PV solar panel and converts it into the type and amount of electricity that is compatible with the electric grid. SiCLAB is using silicon carbide (SiC) semiconductors in its new power switches, which are more efficient than the silicon semiconductors used to conduct electricity in most conventional power switches today. Switches with SiC semiconductors can operate at much higher temperatures, as well as higher voltage and power levels than silicon switches. SiC-based power switches are also smaller than those made with silicon alone, so they result in much smaller and lighter electrical devices. In addition to their use in utility-scale PV inverters, SiCLAB’s new power switches can also be used in wind turbines, railways, and other smart grid applications.
Date: December 31, 2011
Partner: UNT Libraries Government Documents Department

Solid Electrolyte/Electrode Interfaces: Atomistic Behavior Analyzed Via UHV-AFM, Surface Spectroscopies, and Computer Simulations Computational and Experimental Studies of the Cathode/Electrolyte Interface in Oxide Thin Film Batteries

Description: The goals of the research were to understand the structural, dynamic, and chemical properties of solid electrolyte surfaces and the cathode/electrolyte interface at an atomistic and nanometer level using both computational and experimental techniques.
Date: March 21, 2012
Creator: Garofalini, Stephen H.
Partner: UNT Libraries Government Documents Department

Final report - Microbial pathways for the reduction of mercury in saturated subsurface sediments

Description: Mercury is a component of mixed wastes that have contaminated vast areas of the deep subsurface as a result of nuclear weapon and energy production. While this mercury is mostly bound to soil constituents episodes of groundwater contamination are known in some cases resulting in potable water super saturated with Hg(0). Microbial processes that reduce Hg(II) to the elemental form Hg(0) in the saturated subsurface sediments may contribute to this problem. When we started the project, only one microbial pathway for the reduction of Hg(II), the one mediated by the mer operon in mercury resistant bacteria was known. As we had previously demonstrated that the mer mediated process occurred in highly contaminated environments (Schaefer et al., 2004), and mercury concentrations in the subsurface were reported to be low (Krabbenhoft and Babiarz, 1992), we hypothesized that other microbial processes might be active in reducing Hg(II) to Hg(0) in saturated subsurface environments. The specific goals of our projects were: (1) Investigating the potential for Hg(II) reduction under varying electron accepting conditions in subsurface sediments and relating these potential to mer gene distribution; and (2) Examining the physiological and biochemical characteristics of the interactions of anaerobic bacteria with mercury. The results are briefly summarized with references to published papers and manuscripts in preparation where details about our research can be found. Additional information may be found in copies of our published manuscripts and conference proceedings, and our yearly reports that were submitted through the RIMS system.
Date: August 25, 2009
Creator: barkay, Tamar; Young, Lily & Zylstra, Gerben
Partner: UNT Libraries Government Documents Department

Visualizing and Tracking Evolving Features in 3D Unstructured and Adaptive Datasets

Description: The massive amounts of time-varying datasets being generated demand new visualization and quantification techniques. Visualization alone is not sufficient. Without proper measurement information/computations real science cannot be done. Our focus is this work was to combine visualization with quantification of the data to allow for advanced querying and searching. As part of this proposal, we have developed a feature extraction adn tracking methodology which allows researcher to identify features of interest and follow their evolution over time. The implementation is distributed and operates over data In-situ: where it is stored and when it was computed.
Date: August 1, 2002
Creator: Silver, D. & Zabusky, N.
Partner: UNT Libraries Government Documents Department

Conference-EC-US Task Force Joint US-EU Workshop on Metabolomics and Environmental Biotechnology

Description: Since 1990, the EC-US Task Force on Biotechnology Research has been coordinating transatlantic efforts to guide and exploit the ongoing revolution in biotechnology and the life sciences. The Task Force was established in June 1990 by the European Commission and the White House Office of Science and Technology Policy. The Task Force has acted as an effective forum for discussion, coordination, and development of new ideas for the last 18 years. Task Force members are European Commission and US Government science and technology administrators who meet annually to enhance communication across the Atlantic, and to encourage collaborative research. Through sponsoring workshops, and other activities, the Task Force also brings together scientific leaders and early career researchers from both sides of the Atlantic to forecast research challenges and opportunities and to promote better links between researchers. Over the years, by keeping a focus on the future of science, the Task Force has played a key role in establishing a diverse range of emerging scientific fields, including biodiversity research, neuroinformatics, genomics, nanobiotechnology, neonatal immunology, transkingdom molecular biology, biologically-based fuels, and environmental biotechnology. The EC-US Task Force has sponsored a number of Working Groups on topics of mutual transatlantic interest. The idea to create a Working Group on Environmental Biotechnology research was discussed in the Task Force meeting of October 1993. The EC-US Working Group on Environmental Biotechnology set as its mission 'To train the next generation of leaders in environmental biotechnology in the United States and the European Union to work collaboratively across the Atlantic.' Since 1995, the Working Group supported three kinds of activities, all of which focus one early career scientists: (1) Workshops on the use of molecular methods and genomics in environmental biotechnology; (2) Short courses with theoretical, laboratory and field elements; and (3) Short term exchange fellowships. The ...
Date: June 4, 2009
Creator: Young, PI: Lily Y. & Zylstra, Co-PI: Gerben J.
Partner: UNT Libraries Government Documents Department

Final report - Reduction of mercury in saturated subsurface sediments and its potential to mobilize mercury in its elemental form

Description: The goal of our project was to investigate Hg(II) reduction in the deep subsurface. We focused on microbial and abiotic pathways of reduction and explored how it affected the toxicity and mobility of Hg in this unique environment. The project’s tasks included: 1. Examining the role of mer activities in the reduction of Hg(II) in denitrifying enrichment cultures; 2. Investigating the biotic/abiotic reduction of Hg(II) under iron reducing conditions; 3. Examining Hg(II) redox transformations under anaerobic conditions in subsurface sediments from DOE sites.
Date: June 13, 2013
Creator: Bakray, Tamar
Partner: UNT Libraries Government Documents Department

Hot Superplastic Powder Forging for Transparent nanocrystalline Ceramics

Description: The program explored a completely new, economical method of manufacturing nanocrystalline ceramics, Hot Superplastic Powder Forging (HSPF). The goal of the work was the development of nanocrystalline/low porosity optically transparent zirconia/alumina. The high optical transparency should result from lack of grain boundary scattering since grains will be smaller than one tenth the wavelength of light and from elimination of porosity. An important technological potential for this process is manufacturing of envelopes for high-pressure sodium vapor lamps. The technique for fabricating monolithic nanocrystalline material does not begin with powder whose particle diameter is <100 nm as is commonly done. Instead it begins with powder whose particle diameter is on the order of 10-100 microns but contains nanocrystalline crystallites <<100 nm. Spherical particles are quenched from a melt and heat treated to achieve the desired microstructure. Under a moderate pressure within a die or a mold at temperatures of 1100C to 1300C densification is by plastic flow of superplastic particles. A nanocrystalline microstructure results, though some features are greater than 100nm. It was found, for instance, that in the fully dense Al2O3-ZrO2 eutectic specimens that a bicontinuous microstructure exists containing <100 nm ZrO2 particles in a matrix of Al2O3 grains extending over 1-2 microns. Crystallization, growth, phase development and creep during hot pressing and forging were studied for several compositions and so provided some details on development of polycrystalline microstructure from heating quenched ceramics.
Date: May 22, 2006
Creator: Cannon, W. Roger
Partner: UNT Libraries Government Documents Department

Transition Metal Donor-Peptide-Acceptor Complexes: From Intramolecular Electron Transfer Reactions to the Study of Reactive Intermediates

Description: The trans-polyproline (PII) oligomers (Figure 1) are unusually rigid peptide structures which have been extensively studied by our group for peptide mediated intramolecular electron transfer (ET) at long distances. We have previously studied ET across a series of metal ion donor (D) acceptor (A) oligoproline peptides with different distances, driving forces and reorganizational energies. The majority of these experiments involve generating the ET intermediate using pulse radiolysis methods, although more recently photochemical methods are also used. Results of these studies showed that ET across peptides can vary by more than twelve orders of magnitude. Using ruthenium bipyridine donors, ET reaction rate constants across several proline residues (n = 4 - 9) occurred in the millisecond (ms) to {micro}s timescale, thus limiting the proline peptide conformational motions to only minor changes (far smaller than the large changes that occur on the ms to sec timescale, such as trans to cis proline isomerization). The present report describes our large data base of experimental results for D-peptide-A complexes in terms of a model where the involvement of both superexchange and hopping (hole and electron) mechanisms account for the long range ET rate constants observed. Our data shows that the change from superexchange to hopping mechanisms occurs at different distances depending on the type of D and A and their interactions with the peptides. Our model is also consistent with generalized models for superexchange and hopping which have been put forward by a number of theoretical groups to account for long range ET phenomena.
Date: March 11, 2003
Creator: Isied, Stephan S.
Partner: UNT Libraries Government Documents Department

Analytical Chemistry of the Polyphosphates

Description: Additional data were obtained on the separation of linear polymers from cyclic polymers by precipitation with barium chloride. An unexpected peak was observed in the anion-exchange chromatography of a sodium poly-phosphate of n-bar average degree of polymerization) = 6, and the compound represented by this peak was isolated. An end-group titration of this compound by microtechnique proved unequivocally that it is a cyclic phosphate. Although the identification (number of phosphorus atoms per molecule) is not completed, evidence from its position in the elution graph by ion-exchange chromatography' and from paper chromatography indicate that it is probable pentametaphosphate, Na/sub 5/P/sub 5/O/sub 15/, or the boat form of tetrametaphosphate, Na/sub 4/P/sub 4/O/sub 12/. (P.C.H.)
Date: October 17, 1961
Creator: Rieman, W., III & Rothbart, H. L.
Partner: UNT Libraries Government Documents Department

Final report

Description: In the DOE award, DE-FG02-00ER45823, we have used molecular dynamics (MD) computer simulations of the intergranular films (IGFs) present in alumina and silicon nitride materials to address specific questions such as: What is the atomistic structure of the glassy silicate phase? Because of the extremely thin nature of the IGF, do bulk-like glass structure and properties prevail? Does distortion exist in the silicate bonds (which affects bond strength and reactivity) and how is this structure affected by the separation distance between the crystals and/or by the composition of the IGF? Does a structural ordering caused by epitaxial adsorption occur at the IGF/crystal interface? What is the correlation length of this order perpendicular to the interface? How is this ordering affected by composition of the IGF or by the crystals in question? In all simulations, a specific number of ions in stoichiometric ratio were placed as the IGF between two similar crystals, with, in some cases, different crystallographic orientations. The IGF compositions coincided with some of those observed experimentally (calcium aluminosilicate (CAS) glasses in the alumina case, calcium silicon oxy-nitride in the nitride case). The number of ions in the IGF was varied to allow for different thicknesses, although the X and Y dimensions (parallel to the interface) were usually {approx} 50 {angstrom} x 50 {angstrom}. The IGF was melted at a high temperature between the crystals, followed by a slow quench to room temperature, where structural data were collected.
Date: November 12, 2004
Creator: Garofalini, S. H.
Partner: UNT Libraries Government Documents Department

A 20-year data set of surface longwave fluxes in the Arctic

Description: Creation of 20-year data set of surface infrared fluxes from satellite measurements. A reliable estimate of the surface downwelling longwave radiation flux (DLF) is a glaring void in available forcing data sets for models of Arctic sea ice and ocean circulation. We have developed a new method to estimate the DLF from a combination of satellite sounder retrievals and brightness temperatures from the TIROS Operational Vertical Sounder (TOVS), which has flown on NOAA polar-orbiting satellites continuously since late 1979. The overarching goal of this project was to generate a 20-year data set of surface downwelling longwave flux measurements from TOVS data over the Arctic Ocean. Daily gridded fields of DLF were produced with a spatial resolution of (100 km){sup 2} north of 60{sup o}N for 22.5 years rather than only 20. Surface measurements from the field station at Barrow, AK--part of the Atmospheric Radiation Measurement (ARM) Program --and from the Surface Heat Budget of the Arctic (SHEBA) were used to validate the satellite-derived fluxes and develop algorithm improvements for conditions that had resulted in systematic errors in early versions of the algorithm. The resulting data set has already been sent to two other investigators for incorporation into their research, and we will soon complete preparations to send the products to the National Snow and Ice Data Center and ARM data archive, where it can be disseminated to the scientific community.
Date: June 15, 2004
Creator: Francis, Jennifer
Partner: UNT Libraries Government Documents Department

Molecular bases and photobiological consequences of light intensity adaptation in photosynthetic organisms

Description: By applying a combination of light transitions, uncouplers, and inhibitors of photosynthetic electron transport inhibitors we modulate the redox poise of many components in the plastid and examine the pattern of expression of cab1 gene. This gene encodes the major light harvesting protein that services photosystem II. While our results have confirmed our own previous finding that light intensity regulation of cab1 gene expression is signaled by the redox state of the PQ pool, we have also identified additional sensor(s) located in the PET chain.
Date: February 10, 2003
Creator: Chen, Y-B.; Durnford, D.; Koblizek, M. & Falkowski, P. G.
Partner: UNT Libraries Government Documents Department

Bioremediation and Biodegradation: Current Advances in Reducing Toxicity, Exposure and Environmental Consequences

Description: Topics discussed at the conference included Approaches to Overcome Bioavailability Limitations in Bioremediation; New Discoveries in Microbial Degradation of Persistent Environmental Contaminants; Biological Activity and Potential Toxicity of the Products of Biodegradation; New Methods to Monitor and Assess the Effectiveness of Remediation Processes; and Strategies for Remediation of Mixed Contaminants. The United States has thousands of hazardous waste sites, most of which are a legacy of many decades of industrial development, mining, manufacturing and military activities. There is considerable uncertainty about the health risks of these sites, such as a lack of understanding about the spectrum of health effects that could result from exposure to hazardous substances and the unique toxicity of these substances to children or the developing fetus. In addition to these kinds of knowledge gaps, the fate and transport of hazardous wastes in soil, surface water and ground water are poorly understood, making it difficult to predict exposures. Moreover, cleaning up hazardous wastes has proven costly and difficult; thus, there is a need for advanced technologies to decrease or eliminate contamination from soil, surface water, and ground water. Since biodegradative processes and bioremediation solutions form a large part of the current science and technology directed at treatment of environmental contaminants at hazardous waste sites, and since there has been an explosion of cutting-edge basic research in these areas over the past several years, it was an opportune time for a meeting of this type. Representatives from the EPA as well as many of the other Federal agencies that helped fund the conference were also in attendance, providing an opportunity for discussions from the regulatory perspective of hazardous site remediation, as well as from the scientific discovery side.
Date: April 1, 2003
Creator: Kukor, J. J. & Young, L.
Partner: UNT Libraries Government Documents Department

FINAL TECHNICAL REPORT for grant DE-FG02-93ER14353 œ"Carbon-Hydrogen Bond Functionalization Catalyzed by Transition Metal Systems"

Description: Alkanes are our most abundant organic resource but are highly resistant to selective chemical transformations. Alkenes (olefins) by contrast are the single most versatile class of molecules for selective transformations, and are intermediates in virtually every petrochemical process as well as a vast range of commodity and fine chemical processes. Over the course of this project we have developed the most efficient catalysts to date for the selective conversion of alkanes to give olefins, and have applied these catalysts to other dehydrogenation reactions. We have also developed some of the first efficient catalysts for carbonylation of alkanes and arenes to give aldehydes. The development of these catalysts has been accompanied by elucidation of the mechanism of their operation and the factors controlling the kinetics and thermodynamics of C-H bond activation and other individual steps of the catalytic cycles. This fundamental understanding will allow the further improvement of these catalysts, as well as the development of the next generation of catalysts for the functionalization of alkanes and other molecules containing C-H bonds.
Date: May 21, 2012
Creator: Goldman, Alan S.
Partner: UNT Libraries Government Documents Department

Final Report Fermionic Symmetries and Self consistent Shell Model

Description: In this final report in the field of theoretical nuclear physics we note important accomplishments.We were confronted with "anomoulous" magnetic moments by the experimetalists and were able to expain them. We found unexpected partial dynamical symmetries--completely unknown before, and were able to a large extent to expain them.The importance of a self consistent shell model was emphasized.
Date: November 7, 2008
Creator: Zamick, Larry
Partner: UNT Libraries Government Documents Department

Final Technical Report: Discovering the Nature of Dark Energy: Towards Better Distances from Type Ia Supernovae

Description: The final technical report from the project "Discovering the Nature of Dark Energy: Towards Better Distances from Type Ia Supernovae" led at Rutgers the State University of New Jersey by Prof. Saurabh W. Jha is presented, including all publications resulting from this award.
Date: October 3, 2012
Creator: Jha, Saurabh W.
Partner: UNT Libraries Government Documents Department

Final Technical Report: DOE-Biological Ocean Margins Program. Microbial Ecology of Denitrifying Bacteria in the Coastal Ocean.

Description: The focus of our research was to provide a comprehensive study of the bacterioplankton populations off the coast of New Jersey near the Rutgers University marine field station using terminal restriction fragment polymorphism analysis (TRFLP) coupled to 16S rRNA genes for large data set studies. Our three revised objectives to this study became: (1) to describe bacterioplankton population dynamics in the Mid Atlantic Bight using TRFLP analysis of 16S rRNA genes. (2) to determine whether spatial and temporal factors are driving bacterioplankton community dynamics in the MAB using monthly samping along our transect line over a 2-year period. (3) to identify dominant members of a coastal bacterioplankton population by clonal library analysis of 16S rDNA genes and sequencing of PCR product corresponding to specific TRFLP peaks in the data set. Although open ocean time-series sites have been areas of microbial research for years, relatively little was known about the population dynamics of bacterioplankton communities in the coastal ocean on kilometer spatial and seasonal temporal scales. To gain a better understanding of microbial community variability, monthly samples of bacterial biomass were collected in 1995-1996 along a 34-km transect near the Long-Term Ecosystem Observatory (LEO-15) off the New Jersey coast. Surface and bottom sampling was performed at seven stations along a transect line with depths ranging from 1 to 35m (n=178). The data revealed distinct temporal patterns among the bacterioplankton communities in the Mid-Atlantic Bight rather than grouping by sample location or depth (figure 2-next page). Principal components analysis models supported the temporal patterns. In addition, partial least squares regression modeling could not discern a significant correlation from traditional oceanographic physical and phytoplankton nutrient parameters on overall bacterial community variability patterns at LEO-15. These results suggest factors not traditionally measured during oceanographic studies are structuring coastal microbial communities.
Date: January 1, 2013
Creator: Kerkhof, Lee
Partner: UNT Libraries Government Documents Department

Mesoscale Interfacial Dynamics in Magnetoelectric Nanocomposites

Description: Theory and modeling of chessboard-like self-assembling of vertically aligned columnar nanostructures in films has been developed. By means of modeling and three-dimensional computational simulations, we proposed a novel self-assembly process that can produce good chessboard nanostructure architectures through a pseudo-spinodal decomposition of an epitaxial film under optimal thermodynamic and crystallographic conditions (appropriate choice of the temperature, composition of the film, and crystal lattice parameters of the film and substrate). These conditions are formulated. The obtained results have been published on Nano Letters. Based on the principles of the formation of chessboard nanostructured films, we are currently trying to find good decomposing material systems that satisfy the optimal conditions to produce the chessboard nanostructure architecture. In addition we are under way doing 'computer experiments' to look for the appropriate materials with the chessboard columnar nanostructures, as a potential candidate for engineering of optical devices, high-efficiency multiferroics, and high-density magnetic perpendicular recording media. We are also currently to investigate the magnetoelectric response of multiferroic chessboard nanostructures under applied electric/magnetic fields. A unified 3-dimensional phase field theory of the strain-mediated magnetoelectric effect in magnetoelectric composites is developed. The theory is based on the established equivalency paradigm: we proved that by using a variational priciple the exact values of the electric, magnetic and strain fields in a magnetoelectric composite of arbitrary morphology and their coupled magneto-electric-mechanical response can be evaluated by considering an equivalent homogeneous system with the specially chosen effective eigenstrain, polarization and magnetization. These equivalency parameters are spatially inhomogeneous fields, which are obtained by solving the time-dependent Ginzburg-Landau equations. The paper summarizing these results is to be submitted to JAP. We are currently using the computational model based on the unified phase field theory to predict the local and overall response of the magnetoelectric composites with arbitrary configuration under applied fields, and ...
Date: August 6, 2009
Creator: Khachaturyan, Armen G.
Partner: UNT Libraries Government Documents Department