Phase Equilibria Relationships of High-Tc Superconductors (open access)

Phase Equilibria Relationships of High-Tc Superconductors

As an integral part of a R&D program partially supported by the Electricity Delivery and Energy Reliability Office of DOE, we have determined phase equilibria data and phase diagrams for the three generations of superconductor materials: 1st generation, (Bi,Pb)-Sr-Ca- Cu-O systems; 2nd generation, Ba-R-Cu-O systems (R=lanthanides and yttrium); and 3rd generation, MgB2 systems. Our studies involved bulk materials, single crystals and thin films. This report gives a summary of our accomplishments, a list of publications, and 15 selected journal publications
Date: January 11, 2011
Creator: Wong-Ng, Winnie
Object Type: Report
System: The UNT Digital Library
Nanometer-Scale Epitaxial Strain Release in Perovskite Heterostructures Using 'SrAlOx' Sliding Buffer Layers (open access)

Nanometer-Scale Epitaxial Strain Release in Perovskite Heterostructures Using 'SrAlOx' Sliding Buffer Layers

We demonstrate the strain release of LaAlO{sub 3} epitaxial film on SrTiO{sub 3} (001) by inserting ultra-thin 'SrAlO{sub x}' buffer layers. Although SrAlO{sub x} is not a perovskite, nor stable as a single phase in bulk, epitaxy stabilizes the perovskite structure up to a thickness of 2 unit cells (uc). At a critical thickness of 3 uc of SrAlO{sub x}, the interlayer acts as a sliding buffer layer, and abruptly relieves the lattice mismatch between the LaAlO{sub 3} filmand the SrTiO{sub 3} substrate, while maintaining crystallinity. This technique may provide a general approach for strain relaxation of perovskite film far below the thermodynamic critical thickness. A central issue in heteroepitaxial filmgrowth is the inevitable difference in lattice constants between the filmand substrate. Due to this lattice mismatch, thin film are subjected to microstructural strain, which can have a significan effect on the filmproperties. This challenge is especially prominent in the rapidly developing fiel of oxide electronics, where much interest is focused on incorporating the emergent physical properties of oxides in devices. Although strain can be used to great effect to engineer unusual ground states, it is often deleterious for bulk first-orde phase transitions, which are suppressed by the strain and …
Date: August 11, 2011
Creator: Bell, Christopher
Object Type: Article
System: The UNT Digital Library
Search for CP violation in the Decays $D^{\pm} to K^0_{\scriptscriptstyle S} K^\pm$, $D_s^{\pm} to K^0_{\scriptscriptstyle S} K^\pm$, and $D_s^{\pm} to K^0_{\scriptscriptstyle S} p^\pm$ (open access)

Search for CP violation in the Decays $D^{\pm} to K^0_{\scriptscriptstyle S} K^\pm$, $D_s^{\pm} to K^0_{\scriptscriptstyle S} K^\pm$, and $D_s^{\pm} to K^0_{\scriptscriptstyle S} p^\pm$

None
Date: February 11, 2013
Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G. et al.
Object Type: Article
System: The UNT Digital Library
DATA QUALITY OBJECTIVES FOR SELECTING WASTE SAMPLES FOR BENCH-SCALE REFORMER TREATABILITY STUDIES (open access)

DATA QUALITY OBJECTIVES FOR SELECTING WASTE SAMPLES FOR BENCH-SCALE REFORMER TREATABILITY STUDIES

This document describes the data quality objectives to select archived samples located at the 222-S Laboratory for Bench-Scale Reforming testing. The type, quantity, and quality of the data required to select the samples for Fluid Bed Steam Reformer testing are discussed. In order to maximize the efficiency and minimize the time to treat Hanford tank waste in the Waste Treatment and Immobilization Plant, additional treatment processes may be required. One of the potential treatment processes is the fluidized bed steam reformer. A determination of the adequacy of the fluidized bed steam reformer process to treat Hanford tank waste is required. The initial step in determining the adequacy of the fluidized bed steam reformer process is to select archived waste samples from the 222-S Laboratory that will be used in a bench scale tests. Analyses of the selected samples will be required to confirm the samples meet the shipping requirements and for comparison to the bench scale reformer (BSR) test sample selection requirements.
Date: February 11, 2011
Creator: DL, BANNING
Object Type: Report
System: The UNT Digital Library
Energy from Water and Sunlight (open access)

Energy from Water and Sunlight

Advanced Research Projects Agency-Energy project sheet summarizing general information about a new program to develop an energy storage device that converts water and sunlight into a renewable fuel (project title "Affordable Energy from Water and Sunlight") including critical needs, innovation and advantages, impacts, and contact information. This sheet is the first open solicitation, announcing funding opportunities for involvement in the project.
Date: May 11, 2012
Creator: Sun Catalytix
Object Type: Text
System: The UNT Digital Library
Steam Reforming on Transition-metal Carbides from Density-functional Theory (open access)

Steam Reforming on Transition-metal Carbides from Density-functional Theory

A screening study of the steam reforming reaction on clean and oxygen covered early transition-metal carbides surfaces is performed by means of density-functional theory calculations. It is found that carbides provide a wide spectrum of reactivities, from too reactive via suitable to too inert. Several molybdenum-based systems are identified as possible steam reforming catalysts. The findings suggest that carbides provide a playground for reactivity tuning, comparable to the one for pure metals.
Date: May 11, 2012
Creator: Vojvodic, Aleksandra
Object Type: Article
System: The UNT Digital Library
The Component Slope Linear Model for Calculating Intensive Partial Molar Properties: Application to Waste Glasses (open access)

The Component Slope Linear Model for Calculating Intensive Partial Molar Properties: Application to Waste Glasses

Partial molar properties are the changes occurring when the fraction of one component is varied while the fractions of all other component mole fractions change proportionally. They have many practical and theoretical applications in chemical thermodynamics. Partial molar properties of chemical mixtures are difficult to measure because the component mole fractions must sum to one, so a change in fraction of one component must be offset with a change in one or more other components. Given that more than one component fraction is changing at a time, it is difficult to assign a change in measured response to a change in a single component. In this study, the Component Slope Linear Model (CSLM), a model previously published in the statistics literature, is shown to have coefficients that correspond to the intensive partial molar properties. If a measured property is plotted against the mole fraction of a component while keeping the proportions of all other components constant, the slope at any given point on a graph of this curve is the partial molar property for that constituent. Actually plotting this graph has been used to determine partial molar properties for many years. The CSLM directly includes this slope in a model …
Date: January 11, 2013
Creator: Reynolds, Jacob G.
Object Type: Article
System: The UNT Digital Library
Energy, Environmental, and Economic Analyses of Design Concepts for the Co-Production of Fuels and Chemicals with Electricity via Co-Gasification of Coal and Biomass (open access)

Energy, Environmental, and Economic Analyses of Design Concepts for the Co-Production of Fuels and Chemicals with Electricity via Co-Gasification of Coal and Biomass

The overall objective of this project was to quantify the energy, environmental, and economic performance of industrial facilities that would coproduce electricity and transportation fuels or chemicals from a mixture of coal and biomass via co-gasification in a single pressurized, oxygen-blown, entrained-flow gasifier, with capture and storage of CO{sub 2} (CCS). The work sought to identify plant designs with promising (Nth plant) economics, superior environmental footprints, and the potential to be deployed at scale as a means for simultaneously achieving enhanced energy security and deep reductions in U.S. GHG emissions in the coming decades. Designs included systems using primarily already-commercialized component technologies, which may have the potential for near-term deployment at scale, as well as systems incorporating some advanced technologies at various stages of R&D. All of the coproduction designs have the common attribute of producing some electricity and also of capturing CO{sub 2} for storage. For each of the co-product pairs detailed process mass and energy simulations (using Aspen Plus software) were developed for a set of alternative process configurations, on the basis of which lifecycle greenhouse gas emissions, Nth plant economic performance, and other characteristics were evaluated for each configuration. In developing each set of process configurations, focused …
Date: March 11, 2012
Creator: Larson, Eric; Williams, Robert; Kreutz, Thomas; Hannula, Ilkka; Lanzini, Andrea & Liu, Guangjian
Object Type: Report
System: The UNT Digital Library
DOE-NNSA Domestic and International Security Training (open access)

DOE-NNSA Domestic and International Security Training

None
Date: October 11, 2012
Creator: O'Brien, M.
Object Type: Article
System: The UNT Digital Library
MacroAlgae Butanol (open access)

MacroAlgae Butanol

Advanced Research Projects Agency-Energy project sheet summarizing general information about a new program formacroalgae aquafaming to increase feedstock and biofuels (project title "MacroAlgae Butanol") including critical needs, innovation and advantages, impacts, and contact information. This sheet is the first open solicitation, announcing funding opportunities for involvement in the project.
Date: May 11, 2012
Creator: E.I. du Pont de Nemours & Company
Object Type: Text
System: The UNT Digital Library
Computing and Visualizing Reachable Volumes for Maneuvering Satellites (open access)

Computing and Visualizing Reachable Volumes for Maneuvering Satellites

Detecting and predicting maneuvering satellites is an important problem for Space Situational Awareness. The spatial envelope of all possible locations within reach of such a maneuvering satellite is known as the Reachable Volume (RV). As soon as custody of a satellite is lost, calculating the RV and its subsequent time evolution is a critical component in the rapid recovery of the satellite. In this paper, we present a Monte Carlo approach to computing the RV for a given object. Essentially, our approach samples all possible trajectories by randomizing thrust-vectors, thrust magnitudes and time of burn. At any given instance, the distribution of the 'point-cloud' of the virtual particles defines the RV. For short orbital time-scales, the temporal evolution of the point-cloud can result in complex, multi-reentrant manifolds. Visualization plays an important role in gaining insight and understanding into this complex and evolving manifold. In the second part of this paper, we focus on how to effectively visualize the large number of virtual trajectories and the computed RV. We present a real-time out-of-core rendering technique for visualizing the large number of virtual trajectories. We also examine different techniques for visualizing the computed volume of probability density distribution, including volume slicing, convex …
Date: September 11, 2011
Creator: Jiang, M.; de Vries, W. H.; Pertica, A. J. & Olivier, S. S.
Object Type: Article
System: The UNT Digital Library
Cosmic Ray Anomalies from the MSSM? (open access)

Cosmic Ray Anomalies from the MSSM?

The recent positron excess in cosmic rays (CR) observed by the PAMELA satellite may be a signal for dark matter (DM) annihilation. When these measurements are combined with those from FERMI on the total (e{sup +} + e{sup -}) ux and from PAMELA itself on the {anti p}p ratio, these and other results are difficult to reconcile with traditional models of DM, including the conventional minimal Supergravity (mSUGRA) version of Supersymmetry even if boosts as large as 10{sup 3-4} are allowed. In this paper, we combine the results of a previously obtained scan over a more general 19-parameter subspace of the Minimal Supersymmetric Standard Model (MSSM) with a corresponding scan over astrophysical parameters that describe the propagation of CR. We then ascertain whether or not a good fit to this CR data can be obtained with relatively small boost factors while simultaneously satisfying the additional constraints arising from gamma ray data. We find that a specific subclass of MSSM models where the Lightest Supersymmetric Particle (LSP) is mostly pure bino and annihilates almost exclusively into {tau} pairs comes very close to satisfying these requirements. The lightest in this set of models is found to be relatively close in mass to …
Date: August 11, 2011
Creator: Cotta, R. C.; Conley, J. A.; Gainer, J. S.; Hewett, J. L. & Rizzo, T. G.
Object Type: Article
System: The UNT Digital Library
A microscopic theory of low energy fission: fragment properties (open access)

A microscopic theory of low energy fission: fragment properties

None
Date: January 11, 2013
Creator: Younes, W.; Gogny, D. & Schunck, N.
Object Type: Article
System: The UNT Digital Library
CO2 Capture Using Electric Fields (open access)

CO2 Capture Using Electric Fields

Advanced Research Projects Agency-Energy project sheet summarizing general information about a new program for carbon capture and release (project title "Low-Cost Electrochromic Film on Plastic for Net-Zero Energy Building") including critical needs, innovation and advantages, impacts, and contact information. This sheet is the first open solicitation, announcing funding opportunities for involvement in the project.
Date: May 11, 2012
Creator: Lehigh University
Object Type: Text
System: The UNT Digital Library
W-Band Sheet Beam Klystron Design (open access)

W-Band Sheet Beam Klystron Design

Sheet beam devices provide important advantages for very high power, narrow bandwidth RF sources like accelerator klystrons [1]. Reduced current density and increased surface area result in increased power capabi1ity, reduced magnetic fields for focusing and reduced cathode loading. These advantages are offset by increased complexity, beam formation and transport issues and potential for mode competition in the ovennoded cavities and drift tube. This paper will describe the design issues encountered in developing a 100 kW peak and 2 kW average power sheet beam k1ystron at W-band including beam formation, beam transport, circuit design, circuit fabrication and mode competition.
Date: November 11, 2011
Creator: Scheitrum, G.; Caryotakis, G.; Burke, A.; Jensen, A.; Neubauer, M.; Phillips, R. et al.
Object Type: Article
System: The UNT Digital Library
Carbon Nanotube Membranes (open access)

Carbon Nanotube Membranes

Advanced Research Projects Agency-Energy project sheet summarizing general information about a new program to use carbon nanotube membranes for removing carbon dioxide from coal plant exhaust (project title "Carbon Nanotube Membranes for Energy-Efficient Carbon Sequestration") including critical needs, innovation and advantages, impacts, and contact information. This sheet is the first open solicitation, announcing funding opportunities for involvement in the project.
Date: May 11, 2012
Creator: Porifera, Inc.
Object Type: Text
System: The UNT Digital Library
Mask roughness induced LER: geometric model at long correlation lengths (open access)

Mask roughness induced LER: geometric model at long correlation lengths

Collective understanding of how both the resist and line-edge roughness (LER) on the mask affect the final printed LER has made significant advances. What is poorly understood, however, is the extent to which mask surface roughness couples to image plane LER as a function of illumination conditions, NA, and defocus. Recently, progress has been made in formulating a simplified solution for mask roughness induced LER. Here, we investigate the LER behavior at long correlation lengths of surface roughness on the mask. We find that for correlation lengths greater than 3/NA in wafer dimensions and CDs greater than approximately 0.75/NA, the previously described simplified model, which remains based on physical optics, converges to a 'geometric regime' which is based on ray optics and is independent of partial coherence. In this 'geometric regime', the LER is proportional to the mask slope error as it propagates through focus, and provides a faster alternative to calculating LER in contrast to either full 2D aerial image simulation modeling or the newly proposed physical optics model. Data is presented for both an NA = 0.32 and an NA = 0.5 imaging system for CDs of 22-nm and 50-nm horizontal-line-dense structures.
Date: February 11, 2011
Creator: McClinton, Brittany M. & Naulleau, Patrick P.
Object Type: Article
System: The UNT Digital Library
A Measurement of Neutral B Mixing using Di-Lepton Events with the BaBar Detector (open access)

A Measurement of Neutral B Mixing using Di-Lepton Events with the BaBar Detector

None
Date: June 11, 2013
Creator: Gunawardane, N.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
LaVo4: Eu Phosphor Films with Enhanced Eu Solubility (open access)

LaVo4: Eu Phosphor Films with Enhanced Eu Solubility

Eu doped rare-earth orthovanadates are known to be good red phosphor materials. In particular, LaVO{sub 4}:Eu is a promising candidate due to the low Eu-site point symmetry, and thus high dipole transition probability within Judd-Ofelt theory. However, the low solubility limit (< 3 mol %) of Eu in LaVO{sub 4} prevents its efficient use as a phosphor. We present optical evidence of enhanced Eu solubility as high as 10 mol % in LaVO{sub 4}:Eu thin films grown by pulsed laser deposition and postannealing. The photoluminescent intensity exceeded that of YVO{sub 4}:Eu thin films when excited below the host bandgap, indicating stronger direct emission of Eu in LaVO{sub 4}.
Date: August 11, 2011
Creator: Hwang, Harold
Object Type: Article
System: The UNT Digital Library
Driving Oxygen Coordinated Ligand Exchange at Nanocrystal Surfaces using Trialkylsilylated Chalcogenides (open access)

Driving Oxygen Coordinated Ligand Exchange at Nanocrystal Surfaces using Trialkylsilylated Chalcogenides

A general, efficient method is demonstrated for exchanging native oxyanionic ligands on inorganic nanocrystals with functional trimethylsilylated (TMS) chalcogenido ligands. In addition, newly synthesized TMS mixed chalcogenides leverage preferential reactivity of TMS-S bonds over TMS-O bonds, enabling efficient transfer of luminescent nanocrystals into aqueous media with retention of their optical properties.
Date: November 11, 2010
Creator: Caldwell, Marissa A.; Albers, Aaron E.; Levy, Seth C.; Pick, Teresa E.; Cohen, Bruce E.; Helms, Brett A. et al.
Object Type: Article
System: The UNT Digital Library
Manufacture and Testing of Optical-Scale Accelerator Structures from Silicon and Silica (open access)

Manufacture and Testing of Optical-Scale Accelerator Structures from Silicon and Silica

None
Date: October 11, 2013
Creator: Qi, M.; U., /Purdue; Colby, E.R.; England, R.J.; Laouar, R.; McGuinness, C. et al.
Object Type: Article
System: The UNT Digital Library
Discovery of a GeV Blazar Shining Through the Galactic Plane (open access)

Discovery of a GeV Blazar Shining Through the Galactic Plane

The Fermi Large Area Telescope (LAT) discovered a new gamma-ray source near the Galactic plane, Fermi J0109+6134, when it flared brightly in 2010 February. The low Galactic latitude (b = -1.2{sup o}) indicated that the source could be located within the Galaxy, which motivated rapid multi-wavelength follow-up including radio, optical, and X-ray observations. We report the results of analyzing all 19 months of LAT data for the source, and of X-ray observations with both Swift and the Chandra X-ray Observatory. We determined the source redshift, z = 0.783, using a Keck LRIS observation. Finally, we compiled a broadband spectral energy distribution (SED) from both historical and new observations contemporaneous with the 2010 February flare. The redshift, SED, optical line width, X-ray obsorption, and multi-band variability indicate that this new Gev source is a blazar seen through the Galactic plane. Because several of the optical emission lines have equivalent width > 5 {angstrom}, this blazar belongs in the flat-spectrum radio quasar category.
Date: August 11, 2011
Creator: Vandenbroucke, J.; Buehler, R.; Ajello, M.; Bechtol, K.; Bellini, A.; Bolte, M. et al.
Object Type: Article
System: The UNT Digital Library
Design and Characterization of Photoelectrodes from First Principles (open access)

Design and Characterization of Photoelectrodes from First Principles

Although significant performance improvements have been realized since the first demonstration of sunlight-driven water splitting in 1972, mainstream adoption of photoelectrochemical (PEC) cells remains limited by an absence of cost-effective electrodes that show simultaneously high conversion efficiency and good durability. Here we outline current and future efforts to use advanced theoretical techniques to guide the development of a durable, high-performance PEC electrode material. Working in close collaboration with experimental synthesis and characterization teams, we use a twofold approach focusing on: (1) rational design of novel high-performance electrode materials; and (2) characterization and optimization of the electrode-electrolyte interface.
Date: May 11, 2012
Creator: Ogitsu, T.; Wood, B.; Choi, W.; Huda, M. & Wei, S.
Object Type: Report
System: The UNT Digital Library
OSI Passive Seismic Experiment at the Former Nevada Test Site (open access)

OSI Passive Seismic Experiment at the Former Nevada Test Site

On-site inspection (OSI) is one of the four verification provisions of the Comprehensive Nuclear Test Ban Treaty (CTBT). Under the provisions of the CTBT, once the Treaty has entered into force, any signatory party can request an on-site inspection, which can then be carried out after approval (by majority voting) of the Executive Council. Once an OSI is approved, a team of 40 inspectors will be assembled to carry out an inspection to ''clarify whether a nuclear weapon test explosion or any other nuclear explosion has been carried out in violation of Article I''. One challenging aspect of carrying out an on-site inspection (OSI) in the case of a purported underground nuclear explosion is to detect and locate the underground effects of an explosion, which may include an explosion cavity, a zone of damaged rock, and/or a rubble zone associated with an underground collapsed cavity. The CTBT (Protocol, Section II part D, paragraph 69) prescribes several types of geophysical investigations that can be carried out for this purpose. One of the methods allowed by the CTBT for geophysical investigation is referred to in the Treaty Protocol as ''resonance seismometry''. This method, which was proposed and strongly promoted by Russia during …
Date: November 11, 2010
Creator: Sweeney, J. J. & Harben, P.
Object Type: Report
System: The UNT Digital Library