Phase Competition in Trisected Superconducting Dome (open access)

Phase Competition in Trisected Superconducting Dome

None
Date: October 2, 2012
Creator: Vishik, I.M.; Hashimoto, M; He, Rui-Hua; Lee, Wei-Sheng; Schmitt, Felix; Lu, Donghui et al.
Object Type: Article
System: The UNT Digital Library
Center for Technology for Advanced Scientific Component Software (TASCS) (open access)

Center for Technology for Advanced Scientific Component Software (TASCS)

Indiana University’s SWIM activities have primarily been in three areas. All are completed, but we are continuing to work on two of them because refinements are useful to both DoE laboratories and the high performance computing community.
Date: August 2, 2012
Creator: Bramley, Randall B.
Object Type: Report
System: The UNT Digital Library
Theoretical calculating the thermodynamic properties of solid sorbents for CO{sub 2} capture applications (open access)

Theoretical calculating the thermodynamic properties of solid sorbents for CO{sub 2} capture applications

Since current technologies for capturing CO{sub 2} to fight global climate change are still too energy intensive, there is a critical need for development of new materials that can capture CO{sub 2} reversibly with acceptable energy costs. Accordingly, solid sorbents have been proposed to be used for CO{sub 2} capture applications through a reversible chemical transformation. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO{sub 2} sorbent candidates from the vast array of possible solid materials has been proposed and validated. The calculated thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO{sub 2} adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO{sub 2} capture reactions by the solids of interest, we were able to screen only those solid materials for which lower capture energy costs are expected at the desired pressure and temperature conditions. Only those selected CO{sub 2} sorbent candidates were further considered for experimental validations. The ab initio thermodynamic technique has …
Date: November 2, 2012
Creator: Duan, Yuhua
Object Type: Report
System: The UNT Digital Library
Incorporating Afterburn Effects Into A Fast-Running Tool for Modeling Explosives in Tunnels (open access)

Incorporating Afterburn Effects Into A Fast-Running Tool for Modeling Explosives in Tunnels

None
Date: November 2, 2012
Creator: Neuscamman, S; Pezzola, G; Alves, S; Glenn, L & Glascoe, L
Object Type: Article
System: The UNT Digital Library
Renewal of Collaborative Research: Economically viable Forest Harvesting Practices that Increase Carbon Sequestration (open access)

Renewal of Collaborative Research: Economically viable Forest Harvesting Practices that Increase Carbon Sequestration

This technical report covers a 3-year cooperative agreement between the University of Maine and the Northeastern Forest Experiment Station that focused on the characterization of forest stands and the assessment of forest carbon storage (see attached for detailed description of the project). The goal of this work was to compare estimates of forest C storage made via remeasurement of FIA-type plots with eddy flux measurements. In addition to relating whole ecosystem estimates of carbon storage to changes in aboveground biomass, we explored methodologies by partitioning growth estimates from periodic inventory measurements into annual estimates. In the final year, we remeasured plots that were subject to a shelterwood harvest over the winter of 2001-02 to assess the production of coarse woody debris by this harvest, to remeasure trees in a long-term stand first established by NASA, to carry out other field activities at Howland, and, to assess the importance of downed and decaying wood as well as standing dead trees to the C inputs to harvested and non harvested plots.
Date: August 2, 2012
Creator: Dail, David Bryan
Object Type: Report
System: The UNT Digital Library
Semileptonic Decays (open access)

Semileptonic Decays

The following is an overview of the measurements of the CKM matrix elements |V{sub cb}| and |V{sub ub}| that are based on detailed studies of semileptonic B decays by the BABAR and Belle Collaborations and major advances in QCD calculations. In addition, a new and improved measurement of the ratios R(D{sup (*)}) = {Beta}({bar B} {yields} D{sup (*)}{tau}{sup -}{bar {nu}}{sub {tau}})/{Beta}({bar B} {yields} D{sup (*)}{ell}{sup -}{bar {nu}}{sub {ell}}) is presented. Here D{sup (*)} refers to a D or a D* meson and {ell} is either e or {mu}. The results, R(D) = 0.440 {+-} 0.058 {+-} 0.042 and R(D*) = 0.332 {+-} 0.024 {+-} 0.018, exceed the Standard Model expectations by 2.0{sigma} and 2.7{sigma}, respectively. Taken together, they disagree with these expectations at the 3.4{sigma} level. The excess of events cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model.
Date: October 2, 2012
Creator: Luth, Vera G.
Object Type: Article
System: The UNT Digital Library
Interfacial Engineering for Highly Efficient-Conjugated Polymer-Based Bulk Heterojunction Photovoltaic Devices (open access)

Interfacial Engineering for Highly Efficient-Conjugated Polymer-Based Bulk Heterojunction Photovoltaic Devices

The aim of our proposal is to apply interface engineering approach to improve charge extraction, guide active layer morphology, improve materials compatibility, and ultimately allow the fabrication of high efficiency tandem cells. Specifically, we aim at developing: i. Interfacial engineering using small molecule self-assembled monolayers ii. Nanostructure engineering in OPVs using polymer brushes iii. Development of efficient light harvesting and high mobility materials for OPVs iv. Physical characterization of the nanostructured systems using electrostatic force microscopy, and conducting atomic force microscopy v. All-solution processed organic-based tandem cells using interfacial engineering to optimize the recombination layer currents vi. Theoretical modeling of charge transport in the active semiconducting layer The material development effort is guided by advanced computer modeling and surface/ interface engineering tools to allow us to obtain better understanding of the effect of electrode modifications on OPV performance for the investigation of more elaborate device structures. The materials and devices developed within this program represent a major conceptual advancement using an integrated approach combining rational molecular design, material, interface, process, and device engineering to achieve solar cells with high efficiency, stability, and the potential to be used for large-area roll-to-roll printing. This may create significant impact in lowering manufacturing cost …
Date: April 2, 2012
Creator: Jen, Alex; Ginger, David; Luscombe, Christine & Ma, Hong
Object Type: Report
System: The UNT Digital Library
EFFECTIVENESS OF COPPER AND BRONZE FOR ZINC CAPTURE (open access)

EFFECTIVENESS OF COPPER AND BRONZE FOR ZINC CAPTURE

A series of experiments was conducted to determine the efficacy of using copper and bronze sheet and screen under high vacuum conditions to capture zinc vapor. The experiments were conducted in a parametric manner using a fixed zinc vaporization temperature (350°C) but varying the filter temperature from ambient to 550°C. Consistent with previous work, metallic zinc was deposited at low temperatures, but the deposit was non‐adherent. At an intermediate temperature range (350‐450°C), the deposit formed an alloy with both copper and bronze materials. At higher temperatures (> 500°C) the zinc did not deposit on the surfaces likely due to its high vapor pressure. Additional testing to optimize the zinc 'getter' chemistry and surface condition is warranted.
Date: November 2, 2012
Creator: Korinko, P. S.
Object Type: Report
System: The UNT Digital Library
Performance Analysis: Issues Tracking System Data through September 2011 (open access)

Performance Analysis: Issues Tracking System Data through September 2011

None
Date: July 2, 2012
Creator: Kerr, C E; Holman, G & McTyer, N
Object Type: Report
System: The UNT Digital Library
A System for Conducting Sophisticated Mechanical Tests in Situ with High Energy Synchrotron X-Rays Final Technical Report (open access)

A System for Conducting Sophisticated Mechanical Tests in Situ with High Energy Synchrotron X-Rays Final Technical Report

This is the final technical report for the SBIR Phase I project titled 'A System for Conducting Sophisticated Mechanical Tests in Situ with High Energy Synchrotron X-Rays.' Experiments using diffraction of synchrotron radiation that help scientists understand engineering material failure modes, such as fracture and fatigue, require specialized machinery. This machinery must be able to induce these failure modes in a material specimen while adhering to strict size, weight, and geometric limitations prescribed by diffraction measurement techniques. During this Phase I project, Mechanical Solutions, Inc. (MSI) developed one such machine capable of applying uniaxial mechanical loading to a material specimen in both tension and compression, with zero backlash while transitioning between the two. Engineers currently compensate for a lack of understanding of fracture and fatigue by employing factors of safety in crucial system components. Thus, mechanical and structural parts are several times bigger, thicker, and heavier than they need to be. The scientific discoveries that result from diffraction experiments which utilize sophisticated mechanical loading devices will allow for broad material, weight, fuel, and cost savings in engineering design across all industries, while reducing the number of catastrophic failures in transportation, power generation, infrastructure, and all other engineering systems. With an …
Date: August 2, 2012
Creator: Weiss, Jeremy
Object Type: Report
System: The UNT Digital Library
A Fast-running, Physics-Based Tool for Explosives in Tunnels: Model Validation (open access)

A Fast-running, Physics-Based Tool for Explosives in Tunnels: Model Validation

None
Date: February 2, 2012
Creator: Neuscamman, S. J.; Glenn, L. A. & Glascoe, L. G.
Object Type: Article
System: The UNT Digital Library
DISSOLUTION OF PLUTONIUM METAL IN 8-10 M NITRIC ACID (open access)

DISSOLUTION OF PLUTONIUM METAL IN 8-10 M NITRIC ACID

The H-Canyon facility will be used to dissolve Pu metal for subsequent purification and conversion to plutonium dioxide (PuO{sub 2}) using Phase II of HB-Line. To support the new mission, the development of a Pu metal dissolution flowsheet which utilizes concentrated (8-10 M) nitric acid (HNO{sub 3}) solutions containing potassium fluoride (KF) is required. Dissolution of Pu metal in concentrated HNO{sub 3} is desired to eliminate the need to adjust the solution acidity prior to purification by anion exchange. The preferred flowsheet would use 8-10 M HNO{sub 3}, 0.015-0.07 M KF, and 0.5-1.0 g/L Gd to dissolve the Pu up to 6.75 g/L. An alternate flowsheet would use 8-10 M HNO{sub 3}, 0.05-0.2 M KF, and 1-2 g/L B to dissolve the Pu. The targeted average Pu metal dissolution rate is 20 mg/min-cm{sup 2}, which is sufficient to dissolve a “standard” 2250-g Pu metal button in 24 h. Plutonium metal dissolution rate measurements showed that if Gd is used as the nuclear poison, the optimum dissolution conditions occur in 10 M HNO{sub 3}, 0.04-0.05 M KF, and 0.5-1.0 g/L Gd at 112 to 116 °C (boiling). These conditions will result in an estimated Pu metal dissolution rate of ~11-15 mg/min-cm{sup …
Date: July 2, 2012
Creator: Rudisill, T. S. & Pierce, R. A.
Object Type: Report
System: The UNT Digital Library
Low Cost Open-Path Instrument for Monitoring Surface Carbon Dioxide at Sequestration Sites Phase I SBIR Final Report (open access)

Low Cost Open-Path Instrument for Monitoring Surface Carbon Dioxide at Sequestration Sites Phase I SBIR Final Report

Public confidence in safety is a prerequisite to the success of carbon dioxide (CO2) capture and storage for any program that intends to mitigate greenhouse gas emissions. In that regard, this project addresses the security of CO2 containment by undertaking development of what is called “an open path device” to measure CO2 concentrations near the ground above a CO2 storage area.
Date: October 2, 2012
Creator: Wu, Sheng
Object Type: Report
System: The UNT Digital Library
Renewal of Collaborative Research: Economically Viable Forest Harvesting Practices That Increase Carbon Sequestration (open access)

Renewal of Collaborative Research: Economically Viable Forest Harvesting Practices That Increase Carbon Sequestration

Forests provide wildlife habitat, water and air purification, climate moderation, and timber and nontimber products. Concern about climate change has put forests in the limelight as sinks of atmospheric carbon. The C stored in the global vegetation, mostly in forests, is nearly equivalent to the amount present in atmospheric CO{sub 2}. Both voluntary and government-mandated carbon trading markets are being developed and debated, some of which include C sequestration resulting from forest management as a possible tradeable commodity. However, uncertainties regarding sources of variation in sequestration rates, validation, and leakage remain significant challenges for devising strategies to include forest management in C markets. Hence, the need for scientifically-based information on C sequestration by forest management has never been greater. The consequences of forest management on the US carbon budget are large, because about two-thirds of the {approx}300 million hectare US forest resource is classified as 'commercial forest.' In most C accounting budgets, forest harvesting is usually considered to cause a net release of C from the terrestrial biosphere to the atmosphere. However, forest management practices could be designed to meet the multiple goals of providing wood and paper products, creating economic returns from natural resources, while sequestering C from the …
Date: August 2, 2012
Creator: Davidson, E. A.; Dail, D. B.; Hollinger, D.; Scott, N. & Richardson, A.
Object Type: Report
System: The UNT Digital Library
Development Status of PROTEUS-MOC (open access)

Development Status of PROTEUS-MOC

None
Date: November 2, 2012
Creator: Marin-Lafleche, A.; Smith, M. A.; Lewis, E. E. & Lee, C. H. (Nuclear Engineering Division)
Object Type: Report
System: The UNT Digital Library
Compact Couplers for Photonic Crystal Laser-Driven Accelerator Structures (open access)

Compact Couplers for Photonic Crystal Laser-Driven Accelerator Structures

Photonic crystal waveguides are promising candidates for laser-driven accelerator structures because of their ability to confine a speed-of-light mode in an all-dielectric structure. Because of the difference between the group velocity of the waveguide mode and the particle bunch velocity, fields must be coupled into the accelerating waveguide at frequent intervals. Therefore efficient, compact couplers are critical to overall accelerator efficiency. We present designs and simulations of high-efficiency coupling to the accelerating mode in a three-dimensional photonic crystal waveguide from a waveguide adjoining it at 90{sup o}. We discuss details of the computation and the resulting transmission. We include some background on the accelerator structure and photonic crystal-based optical acceleration in general.
Date: July 2, 2012
Creator: Cowan, Benjamin; Lin, M. C.; Schwartz, Brian; Byer, Robert; McGuinness, Christopher; /Stanford U., Phys. Dept. et al.
Object Type: Article
System: The UNT Digital Library
Adaptive Algebraic Multigrid for Finite Element Elliptic Equations with Random Coefficients (open access)

Adaptive Algebraic Multigrid for Finite Element Elliptic Equations with Random Coefficients

This thesis presents a two-grid algorithm based on Smoothed Aggregation Spectral Element Agglomeration Algebraic Multigrid (SA-{rho}AMGe) combined with adaptation. The aim is to build an efficient solver for the linear systems arising from discretization of second-order elliptic partial differential equations (PDEs) with stochastic coefficients. Examples include PDEs that model subsurface flow with random permeability field. During a Markov Chain Monte Carlo (MCMC) simulation process, that draws PDE coefficient samples from a certain distribution, the PDE coefficients change, hence the resulting linear systems to be solved change. At every such step the system (discretized PDE) needs to be solved and the computed solution used to evaluate some functional(s) of interest that then determine if the coefficient sample is acceptable or not. The MCMC process is hence computationally intensive and requires the solvers used to be efficient and fast. This fact that at every step of MCMC the resulting linear system changes, makes an already existing solver built for the old problem perhaps not as efficient for the problem corresponding to the new sampled coefficient. This motivates the main goal of our study, namely, to adapt an already existing solver to handle the problem (with changed coefficient) with the objective to achieve …
Date: April 2, 2012
Creator: Kalchev, D
Object Type: Report
System: The UNT Digital Library
Imaging gene expression in real-time using aptamers (open access)

Imaging gene expression in real-time using aptamers

Signal transduction pathways are usually activated by external stimuli and are transient. The downstream changes such as transcription of the activated genes are also transient. Real-time detection of promoter activity is useful for understanding changes in gene expression, especially during cell differentiation and in development. A simple and reliable method for viewing gene expression in real time is not yet available. Reporter proteins such as fluorescent proteins and luciferase allow for non-invasive detection of the products of gene expression in living cells. However, current reporter systems do not provide for real-time imaging of promoter activity in living cells. This is because of the long time period after transcription required for fluorescent protein synthesis and maturation. We have developed an RNA reporter system for imaging in real-time to detect changes in promoter activity as they occur. The RNA reporter uses strings of RNA aptamers that constitute IMAGEtags (Intracellular MultiAptamer GEnetic tags), which can be expressed from a promoter of choice. The tobramycin, neomycin and PDC RNA aptamers have been utilized for this system and expressed in yeast from the GAL1 promoter. The IMAGEtag RNA kinetics were quantified by RT-qPCR. In yeast precultured in raffinose containing media the GAL1 promoter responded faster …
Date: November 2, 2012
Creator: Shin, Il Chung
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Single crystal Processing and magnetic properties of gadolinium nickel (open access)

Single crystal Processing and magnetic properties of gadolinium nickel

GdNi is a rare earth intermetallic material that exhibits very interesting magnetic properties. Spontaneous magnetostriction occurs in GdNi at T{sub C}, on the order of 8000ppm strain along the c-axis and only until very recently the mechanism causing this giant magnetostriction was not understood. In order to learn more about the electronic and magnetic structure of GdNi, single crystals are required for anisotropic magnetic property measurements. Single crystal processing is quite challenging for GdNi though since the rare-earth transition-metal composition yields a very reactive intermetallic compound. Many crystal growth methods are pursued in this study including crucible free methods, precipitation growths, and specially developed Bridgman crucibles. A plasma-sprayed Gd{sub 2}O{sub 3} W-backed Bridgman crucible was found to be the best means of GdNi single crystal processing. With a source of high-quality single crystals, many magnetization measurements were collected to reveal the magnetic structure of GdNi. Heat capacity and the magnetocaloric effect are also measured on a single crystal sample. The result is a thorough report on high quality single crystal processing and the magnetic properties of GdNi.
Date: November 2, 2012
Creator: Shreve, Andrew John
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Upgrade of the Drive LINAC for the AWA Facility Dielectric Two-Beam Accelerator (open access)

Upgrade of the Drive LINAC for the AWA Facility Dielectric Two-Beam Accelerator

We report on the design of a seven-cell, standing-wave, 1.3-GHz rf cavity and the associated beam dynamics studies for the upgrade of the drive beamline LINAC at the Argonne Wakefield Accelerator (AWA) facility. The LINAC design is a compromise between single-bunch operation (100 nC {at} 75 MeV) and minimization of the energy droop along the bunch train during bunch-train operation. The 1.3-GHz drive bunch-train target parameters are 75 MeV, 10-20-ns macropulse duration, and 16 x 60 nC microbunches; this is equivalent to a macropulse current and beam power of 80 A and 6 GW, respectively. Each LINAC structure accelerates approximately 1000 nC in 10 ns by a voltage of 11 MV at an rf power of 10 MW. Due to the short bunch-train duration desired ({approx}10 ns) and the existing frequency (1.3 GHz), compensation of the energy droop along the bunch train is difficult to accomplish by means of the two standard techniques: time-domain or frequency-domain beam loading compensation. Therefore, to minimize the energy droop, our design is based on a large stored energy rf cavity. In this paper, we present our rf cavity optimization method, detailed rf cavity design, and beam dynamics studies of the drive beamline.
Date: July 2, 2012
Creator: Power, John; Conde, Manoel; Gai, Wei; Li, Zenghai & Mihalcea, Daniel
Object Type: Article
System: The UNT Digital Library
Measurement and Modeling of the n=2-3 Emission of O VIII near 102 �A (open access)

Measurement and Modeling of the n=2-3 Emission of O VIII near 102 �A

None
Date: October 2, 2012
Creator: Trabert, E & Beiersdorfer, P
Object Type: Article
System: The UNT Digital Library
Large Scale Computing and Storage Requirements for Nuclear Physics Research (open access)

Large Scale Computing and Storage Requirements for Nuclear Physics Research

IThe National Energy Research Scientific Computing Center (NERSC) is the primary computing center for the DOE Office of Science, serving approximately 4,000 users and hosting some 550 projects that involve nearly 700 codes for a wide variety of scientific disciplines. In addition to large-scale computing resources NERSC provides critical staff support and expertise to help scientists make the most efficient use of these resources to advance the scientific mission of the Office of Science. In May 2011, NERSC, DOE’s Office of Advanced Scientific Computing Research (ASCR) and DOE’s Office of Nuclear Physics (NP) held a workshop to characterize HPC requirements for NP research over the next three to five years. The effort is part of NERSC’s continuing involvement in anticipating future user needs and deploying necessary resources to meet these demands. The workshop revealed several key requirements, in addition to achieving its goal of characterizing NP computing. The key requirements include: 1. Larger allocations of computational resources at NERSC; 2. Visualization and analytics support; and 3. Support at NERSC for the unique needs of experimental nuclear physicists. This report expands upon these key points and adds others. The results are based upon representative samples, called “case studies,” of the needs …
Date: March 2, 2012
Creator: Gerber, Richard A. & Wasserman, Harvey J.
Object Type: Report
System: The UNT Digital Library
Kinetics of Colloidal Silica Gelation at EGS Conditions and Implications for Reservoir Modification (open access)

Kinetics of Colloidal Silica Gelation at EGS Conditions and Implications for Reservoir Modification

None
Date: May 2, 2012
Creator: Hunt, J. D.; Ezzedine, S. M.; Bourcier, W. & Roberts, S.
Object Type: Article
System: The UNT Digital Library
Reduction And Stabilization (Immobilization) Of Pertechnetate To An Immobile Reduced Technetium Species Using Tin(II) Apatite (open access)

Reduction And Stabilization (Immobilization) Of Pertechnetate To An Immobile Reduced Technetium Species Using Tin(II) Apatite

Synthetic tin(II)apatite reduces pertechnetate from the mobile +7 to a non-mobile oxidation state and sequesters the technetium, preventing re-oxidization to mobile +7 state under acidic or oxygenated conditions. Previous work indicated technetium reacted Sn(II)apatite can achieve an ANSI leachability index of 12.8 in Cast Stone. An effect by pH is observed on the distribution coefficient, the highest distribution coefficient being l70,900 observed at pH levels of 2.5 to 10.2. The tin apatite was resistant to releasing technetium under test conditions.
Date: November 2, 2012
Creator: Duncan, J. B.
Object Type: Article
System: The UNT Digital Library