Energetics of Oxygen Adatoms, Hydroxyl Species and Water Dissociation on Pt(111) (open access)

Energetics of Oxygen Adatoms, Hydroxyl Species and Water Dissociation on Pt(111)

None
Date: January 18, 2013
Creator: Karp, Eric M.; Campbell, Charles T.; /Washington U., Dept. Chem.; Studt, Felix; Abild-Pedersen, Frank; Norskov, Jens K. et al.
Object Type: Article
System: The UNT Digital Library
Six Thousand Electrochemical Cycles of Double-Walled Silicon Nanotube Anodes for Lithium Ion Batteries (open access)

Six Thousand Electrochemical Cycles of Double-Walled Silicon Nanotube Anodes for Lithium Ion Batteries

Despite remarkable progress, lithium ion batteries still need higher energy density and better cycle life for consumer electronics, electric drive vehicles and large-scale renewable energy storage applications. Silicon has recently been explored as a promising anode material for high energy batteries; however, attaining long cycle life remains a significant challenge due to materials pulverization during cycling and an unstable solid-electrolyte interphase. Here, we report double-walled silicon nanotube electrodes that can cycle over 6000 times while retaining more than 85% of the initial capacity. This excellent performance is due to the unique double-walled structure in which the outer silicon oxide wall confines the inner silicon wall to expand only inward during lithiation, resulting in a stable solid-electrolyte interphase. This structural concept is general and could be extended to other battery materials that undergo large volume changes.
Date: August 18, 2011
Creator: Wu, H
Object Type: Article
System: The UNT Digital Library
FOAM FORMATION IN THE SALTSTONE PRODUCTION FACILITY: EVALUATION OF SOURCES AND MITIGATION (open access)

FOAM FORMATION IN THE SALTSTONE PRODUCTION FACILITY: EVALUATION OF SOURCES AND MITIGATION

The Saltstone Production Facility receives waste from Tank 50H for treatment. Influents into Tank 50H include the Effluent Treatment Project waste concentrate, H-Canyon low activity waste and General Purpose Evaporator bottoms, Modular Caustic Side Solvent Extraction Unit decontaminated salt solution, and salt solution from the Deliquification, Dissolution and Adjust campaign. Using the Waste Characterization System (WCS), this study tracks the relative amounts of each influent into Tank 50H, as well as the total content of Tank 50H, in an attempt to identify the source of foaming observed in the Saltstone Production Facility hopper. Saltstone has been using antifoam as part of routine processing with the restart of the facility in December 2006. It was determined that the maximum admix usage in the Saltstone Production Facility, both antifoam and set retarder, corresponded with the maximum concentration of H-Canyon low activity waste in Tank 50H. This paper also evaluates archived salt solutions from Waste Acceptance Criteria analysis for propensity to foam and the antifoam dosage required to mitigate foaming. It was determined that Effluent Treatment Project contributed to the expansion factor (foam formation) and General Purpose Evaporator contributed to foaminess (persistence). It was also determined that undissolved solids contribute to foam persistence. …
Date: January 18, 2011
Creator: Cozzi, A.
Object Type: Report
System: The UNT Digital Library
Alpha Heating in ITER L-mode and H-mode Plasma (open access)

Alpha Heating in ITER L-mode and H-mode Plasma

There are many uses of predictions of ITER plasma performance. One is assessing requirements of different plasma regimes. For instance, what current drive and control are needed for steady state. The heating, current drive, and torque systems planned for initial DT operation are negative ion neutral beam injection (NB), ion cyclotron resonance (IC), and electron cyclotron resonance (EC). Which combinations of heating are optimal. What are benefits of the torques, current drive, and fueling using NB. What are the shine-through power and optimum voltage for the NB? What are optimal locations and aiming of the EC launchers? Another application is nuclear licensing (e.g. System integrity, how many neutrons).
Date: July 18, 2011
Creator: Budny, R.V.
Object Type: Article
System: The UNT Digital Library
ANALYTICAL RESULTS OF MOX COLEMANITE CONCRETE SAMPLE POURED JULY 25, 2012 - CURED 28 DAYS (open access)

ANALYTICAL RESULTS OF MOX COLEMANITE CONCRETE SAMPLE POURED JULY 25, 2012 - CURED 28 DAYS

The Mixed Oxide Fuel Fabrication Facility (MFFF) will use Colemanite bearing concrete neutron absorber panels credited with attenuating neutron flux in the criticality design analyses and shielding operators from radiation. The Savannah River National Laboratory is tasked with measuring the total density, partial hydrogen density, and partial boron density of the colemanite concrete. Samples 8.1.2, 8.2.2, 8.3.2, and 8.4.2 were received on 8/1/2012 and analyzed after curing for 28 days. The average total density measured by the ASTM method C 642 was 2.09 g/cm{sup 3}, within the lower bound of 1.88 g/cm{sup 3}. The average partial hydrogen density was 7.48E-02 g/cm{sup 3} as measured using method ASTM E 1311 and met the lower bound of 6.04E-02 g/cm{sup 3}. The average measured partial boron density was 1.71E-01 g/cm{sup 3} which met the lower bound of 1.65E-01 g/cm{sup 3} measured by the ASTM C 1301 method.
Date: September 18, 2012
Creator: Cozzi, A. D.; Best, D. R. & Reigel, M. M.
Object Type: Report
System: The UNT Digital Library
Effect of Finite Pulse Length and Laser Frequency Chirp on HGHG and EEHG Seeding (open access)

Effect of Finite Pulse Length and Laser Frequency Chirp on HGHG and EEHG Seeding

Theoretical studies of high-gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) often start from a simplified model in which the beam is assumed infinitely long and longitudinally uniform and the laser induced energy modulation is perfectly sinusoidal and of infinite duration. In such a model the resulting seed has a spectrum consisting of a collection of delta-functions (of zero width) located at the harmonics of the laser frequency. Being a useful tool for study of the seed bunching amplitudes, such a model cannot be used for realistic analysis the spectral properties of the seed. In this paper we take into account the finite duration of the laser pulse as well as some possible laser phase errors to study their effect on the spectrum of the seed.
Date: November 18, 2011
Creator: Stupakov, G.
Object Type: Report
System: The UNT Digital Library
F-18 Labeled Diabody-Luciferase Fusion Proteins for Optical-ImmunoPET (open access)

F-18 Labeled Diabody-Luciferase Fusion Proteins for Optical-ImmunoPET

The goal of the proposed work is to develop novel dual-labeled molecular imaging probes for multimodality imaging. Based on small, engineered antibodies called “diabodies”, these probes will be radioactively tagged with Fluorine-18 for PET imaging, and fused to luciferases for optical (bioluminescence) detection. Performance will be evaluated and validated using a prototype integrated optical-PET imaging system, OPET. Multimodality probes for optical-PET imaging will be based on diabodies that are dually labeled with 18F for PET detection and fused to luciferases for optical imaging. 1) Two sets of fusion proteins will be built, targeting the cell surface markers CEA or HER2. Coelenterazine-based luciferases and variant forms will be evaluated in combination with native substrate and analogs, in order to obtain two distinct probes recognizing different targets with different spectral signatures. 2) Diabody-luciferase fusion proteins will be labeled with 18F using amine reactive [18F]-SFB produced using a novel microwave-assisted, one-pot method. 3) Sitespecific, chemoselective radiolabeling methods will be devised, to reduce the chance that radiolabeling will inactivate either the target-binding properties or the bioluminescence properties of the diabody-luciferase fusion proteins. 4) Combined optical and PET imaging of these dual modality probes will be evaluated and validated in vitro and in vivo using …
Date: January 18, 2013
Creator: Wu, Anna M.
Object Type: Report
System: The UNT Digital Library
In vitro High-Resolution Architecture and Structural Dynamics of Bacterial Systems (open access)

In vitro High-Resolution Architecture and Structural Dynamics of Bacterial Systems

None
Date: March 18, 2010
Creator: Malkin, A. J.; Plomp, M.; Leighton, T. J.; Vogelstein, B. & Holman, H.
Object Type: Article
System: The UNT Digital Library
Documentation, User Support, and Verification of Wind Turbine and Plant Models (open access)

Documentation, User Support, and Verification of Wind Turbine and Plant Models

As part of the Utility Wind Energy Integration Group (UWIG) and EnerNex's Wind Turbine Modeling Project, EnerNex has received ARRA (federal stimulus) funding through the Department of Energy (DOE) to further the progress of wind turbine and wind plant models. Despite the large existing and planned wind generation deployment, industry-standard models for wind generation have not been formally adopted. Models commonly provided for interconnection studies are not adequate for use in general transmission planning studies, where public, non-proprietary, documented and validated models are needed. NERC MOD (North American Electric Reliability Corporation) reliability standards require that power flow and dynamics models be provided, in accordance with regional requirements and procedures. The goal of this project is to accelerate the appropriate use of generic wind turbine models for transmission network analysis by: (1) Defining proposed enhancements to the generic wind turbine model structures that would allow representation of more advanced; (2) Comparative testing of the generic models against more detailed (and sometimes proprietary) versions developed by turbine vendors; (3) Developing recommended parameters for the generic models to best mimic the performance of specific commercial wind turbines; (4) Documenting results of the comparative simulations in an application guide for users; (5) Conducting technology …
Date: September 18, 2012
Creator: Zavadil, Robert; Zheglov, Vadim; Kazachkov, Yuriy; Gong, Bo; Sanchez, Juan & Li, Jun
Object Type: Report
System: The UNT Digital Library
3D Surface Mapping of Capsule Fill-Tube Assemblies used in Laser-Driven Fusion Targets (open access)

3D Surface Mapping of Capsule Fill-Tube Assemblies used in Laser-Driven Fusion Targets

This paper presents the development of a 3D surface mapping system used to measure the surface of a fusion target Capsule Fill-Tube Assembly (CFTA). The CFTA consists of a hollow Ge-doped plastic sphere, called a capsule, ranging in outer diameter between 2.2 mm and 2.6 mm and an attached 150 {micro}m diameter glass-core fill-tube that tapers down to a 10{micro} diameter at the capsule. The mapping system is an enabling technology to facilitate a quality assurance program and to archive 3D surface information of each capsule used in fusion ignition experiments that are currently being performed at the National Ignition Facility (NIF). The 3D Surface Mapping System is designed to locate and quantify surface features with a height of 50 nm and 300 nm in width or larger. Additionally, the system will be calibrated such that the 3D measured surface can be related to the capsule surface angular coordinate system to within 0.25 degree (1{sigma}), which corresponds to approximately 5 {micro}m linear error on the capsule surface.
Date: February 18, 2011
Creator: Buice, E. S.; Alger, E. T.; Antipa, N. A.; Bhandarkar, S. D.; Biesiada, T. A.; Conder, A. D. et al.
Object Type: Article
System: The UNT Digital Library
Remote Handled Transuranic Sludge Retrieval Transfer And Storage System At Hanford (open access)

Remote Handled Transuranic Sludge Retrieval Transfer And Storage System At Hanford

This paper describes the systems developed for processing and interim storage of the sludge managed as remote-handled transuranic (RH-TRU). An experienced, integrated CH2M HILL/AFS team was formed to design and build systems to retrieve, interim store, and treat for disposal the K West Basin sludge, namely the Sludge Treatment Project (STP). A system has been designed and is being constructed for retrieval and interim storage, namely the Engineered Container Retrieval, Transfer and Storage System (ECRTS).
Date: October 18, 2012
Creator: Raymond, Rick E.; Frederickson, James R.; Criddle, James; Hamilton, Dennis & Johnson, Mike W.
Object Type: Article
System: The UNT Digital Library
BERYLLIUM MEASUREMENT IN COMMERCIALLY AVAILABLE WET WIPES (open access)

BERYLLIUM MEASUREMENT IN COMMERCIALLY AVAILABLE WET WIPES

Analysis for beryllium by fluorescence is now an established method which is used in many government-run laboratories and commercial facilities. This study investigates the use of this technique using commercially available wet wipes. The fluorescence method is widely documented and has been approved as a standard test method by ASTM International and the National Institute for Occupational Safety and Health (NIOSH). The procedure involves dissolution of samples in aqueous ammonium bifluoride solution and then adding a small aliquot to a basic hydroxybenzoquinoline sulfonate fluorescent dye (Berylliant{trademark} Inc. Detection Solution Part No. CH-2) , and measuring the fluorescence. This method is specific to beryllium. This work explores the use of three different commercial wipes spiked with beryllium, as beryllium acetate or as beryllium oxide and subsequent analysis by optical fluorescence. The effect of possible interfering metals such as Fe, Ti and Pu in the wipe medium is also examined.
Date: February 18, 2011
Creator: Youmans-Mcdonald, L.
Object Type: Article
System: The UNT Digital Library
Current Trends in Gamma Ray Detection for Radiological Emergency Response (open access)

Current Trends in Gamma Ray Detection for Radiological Emergency Response

Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies.
Date: August 18, 2011
Creator: Mukhopadhyay, S., Guss, P., Maurer, R.
Object Type: Article
System: The UNT Digital Library
Community Wind: Once Again Pushing the Envelope of Project Finance (open access)

Community Wind: Once Again Pushing the Envelope of Project Finance

In the United States, the 'community wind' sector - loosely defined here as consisting of relatively small utility-scale wind power projects that sell power on the wholesale market and that are developed and owned primarily by local investors - has historically served as a 'test bed' or 'proving grounds' for up-and-coming wind turbine manufacturers that are trying to break into the U.S. wind power market. For example, community wind projects - and primarily those located in the state of Minnesota - have deployed the first U.S. installations of wind turbines from Suzlon (in 2003), DeWind (2008), Americas Wind Energy (2008) and later Emergya Wind Technologies (2010), Goldwind (2009), AAER/Pioneer (2009), Nordic Windpower (2010), Unison (2010), and Alstom (2011). Thus far, one of these turbine manufacturers - Suzlon - has subsequently achieved some success in the broader U.S. wind market as well. Just as it has provided a proving grounds for new turbines, so too has the community wind sector served as a laboratory for experimentation with innovative new financing structures. For example, a variation of one of the most common financing arrangements in the U.S. wind market today - the special allocation partnership flip structure (see Figure 1 in Section …
Date: January 18, 2011
Creator: bolinger, Mark A.
Object Type: Report
System: The UNT Digital Library
Austin's Home Performance with Energy Star Program: Making a Compelling Offer to a Financial Institution Partner (open access)

Austin's Home Performance with Energy Star Program: Making a Compelling Offer to a Financial Institution Partner

Launched in 2006, over 8,700 residential energy upgrades have been completed through Austin Energy's Home Performance with Energy Star (HPwES) program. The program's lending partner, Velocity Credit Union (VCU) has originated almost 1,800 loans, totaling approximately $12.5 million. Residential energy efficiency loans are typically small, and expensive to originate and service relative to larger financing products. National lenders have been hesitant to deliver attractive loan products to this small, but growing, residential market. In response, energy efficiency programs have found ways to partner with local and regional banks, credit unions, community development finance institutions (CDFIs) and co-ops to deliver energy efficiency financing to homeowners. VCU's experience with the Austin Energy HPwES program highlights the potential benefits of energy efficiency programs to a lending partner.
Date: March 18, 2011
Creator: Zimring, Mark
Object Type: Report
System: The UNT Digital Library
Black Hole Remnants in the Early Universe (open access)

Black Hole Remnants in the Early Universe

None
Date: June 18, 2013
Creator: Scardigli, Fabio; Gruber, Christine; /Taiwan, Natl. Taiwan U.; Chen, Pisin & /Taiwan, Natl. Taiwan U. /KIPAC, Menlo Park /SLAC
Object Type: Article
System: The UNT Digital Library
EXPERIMENTAL INVESTIGATION OF NATURAL CONVECTION HEAT TRANSFER OF IONIC LIQUID IN A RECTANGULAR ENCLOSURE HEATED FROM BELOW (open access)

EXPERIMENTAL INVESTIGATION OF NATURAL CONVECTION HEAT TRANSFER OF IONIC LIQUID IN A RECTANGULAR ENCLOSURE HEATED FROM BELOW

This paper presents an experimental study of natural convection heat transfer for an Ionic Liquid. The experiments were performed for 1-butyl-2, 3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, ([C{sub 4}mmim][NTf{sub 2}]) at a Raleigh number range of 1.26 x 10{sup 7} to 8.3 x 10{sup 7}. In addition to determining the convective heat transfer coefficients, this study also included experimental determination of thermophysical properties of [C{sub 4}mmim][NTf{sub 2}] such as, density, viscosity, heat capacity, and thermal conductivity. The results show that the density of [C{sub 4}mmim][NTf{sub 2}] varies from 1.437-1.396 g/cm{sup 3} within the temperature range of 10-50 C, the thermal conductivity varies from 0.105-0.116 W/m.K between a temperature of 10 to 60 C, the heat capacity varies from 1.015 J/g.K - 1.760 J/g.K within temperature range of 25-340 C and the viscosity varies from 18cp-243cp within temperature range 10-75 C. The results for density, thermal conductivity, heat capacity, and viscosity were in close agreement with the values in the literature. Measured dimensionless Nusselt number was observed to be higher for the ionic liquid than that of DI water. This is expected as Nusselt number is the ratio of heat transfer by convection to conduction and the ionic liquid has lower thermal conductivity (approximately 18%) …
Date: July 18, 2011
Creator: Fox, E.; Visser, A. & Bridges, N.
Object Type: Article
System: The UNT Digital Library
A Framework for Incorporating General Domain Knowledge into Latent Dirichlet Allocation using First-Order Logic (open access)

A Framework for Incorporating General Domain Knowledge into Latent Dirichlet Allocation using First-Order Logic

Topic models have been used successfully for a variety of problems, often in the form of application-specific extensions of the basic Latent Dirichlet Allocation (LDA) model. Because deriving these new models in order to encode domain knowledge can be difficult and time-consuming, we propose the Fold-all model, which allows the user to specify general domain knowledge in First-Order Logic (FOL). However, combining topic modeling with FOL can result in inference problems beyond the capabilities of existing techniques. We have therefore developed a scalable inference technique using stochastic gradient descent which may also be useful to the Markov Logic Network (MLN) research community. Experiments demonstrate the expressive power of Fold-all, as well as the scalability of our proposed inference method.
Date: January 18, 2011
Creator: Andrzejewski, D.; Zhu, X.; Craven, M. & Recht, B.
Object Type: Article
System: The UNT Digital Library
Energy Savings Assessment for Digital-to-Analog Converter Boxes (open access)

Energy Savings Assessment for Digital-to-Analog Converter Boxes

The Digital Television (DTV) Converter Box Coupon Program was administered by the U.S. government to subsidize purchases of digital-to-analog converter boxes, with up to two $40 coupons for each eligible household. In order to qualify as Coupon Eligible Converter Boxes (CECBs), these devices had to meet a number of minimum performance specifications, including energy efficiency standards. The Energy Star Program also established voluntary energy efficiency specifications that are more stringent than the CECB requirements. In this study, we measured the power and energy consumptions for a sample of 12 CECBs (including 6 Energy Star labeled models) in-use in homes and estimated aggregate energy savings produced by the energy efficiency policies. Based on the 35 million coupons redeemed through the end of the program, our analysis indicates that between 2500 and 3700 GWh per year are saved as a result of the energy efficiency policies implemented on digital-to-analog converter boxes. The energy savings generated are equivalent to the annual electricity use of 280,000 average US homes.
Date: January 18, 2011
Creator: Cheung, Hoi Ying Iris; Meier, Alan & Brown, Richard
Object Type: Article
System: The UNT Digital Library
Feature-Based Statistical Analysis of Combustion Simulation Data (open access)

Feature-Based Statistical Analysis of Combustion Simulation Data

We present a new framework for feature-based statistical analysis of large-scale scientific data and demonstrate its effectiveness by analyzing features from Direct Numerical Simulations (DNS) of turbulent combustion. Turbulent flows are ubiquitous and account for transport and mixing processes in combustion, astrophysics, fusion, and climate modeling among other disciplines. They are also characterized by coherent structure or organized motion, i.e. nonlocal entities whose geometrical features can directly impact molecular mixing and reactive processes. While traditional multi-point statistics provide correlative information, they lack nonlocal structural information, and hence, fail to provide mechanistic causality information between organized fluid motion and mixing and reactive processes. Hence, it is of great interest to capture and track flow features and their statistics together with their correlation with relevant scalar quantities, e.g. temperature or species concentrations. In our approach we encode the set of all possible flow features by pre-computing merge trees augmented with attributes, such as statistical moments of various scalar fields, e.g. temperature, as well as length-scales computed via spectral analysis. The computation is performed in an efficient streaming manner in a pre-processing step and results in a collection of meta-data that is orders of magnitude smaller than the original simulation data. This meta-data …
Date: November 18, 2011
Creator: Bennett, J; Krishnamoorthy, V; Liu, S; Grout, R; Hawkes, E; Chen, J et al.
Object Type: Article
System: The UNT Digital Library
Studies of Ds Decays at BaBar (open access)

Studies of Ds Decays at BaBar

We present a measurement of the absolute branching fractions {Beta}(D{sub s}{sup -} {yields} {mu}{sup -}{bar {nu}}{sub {mu}}) and {Beta}(D{sub s}{sup -} {yields} {tau}{sup -}{bar {nu}}{sub {tau}}) and of the D{sub s} decay constant, f{sub D{sub s}}. They also obtain an upper limit on {Beta}(D{sub s}{sup -} {yields} e{bar {nu}}{sub e}). Then they present results on Dalitz plot analysis of D{sub s}{sup +} decays to K{sup +}K{sup -}{pi}{sup +} and {pi}{sup +}{pi}{sup -}{pi}{sup +}. The {pi}{sup +}{pi}{sup -} and K{sup +}K{sup -} S-waves are extracted by a model-independent partial wave analysis. Finally they measure relative branching fractions of D{sub s}{sup +} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup +}, D{sub s}{sup +} {yields} K{sup +}K{sup -}K{sup +}, and D{sub s}{sup +} {yields} K{sup +}K{sup +}{pi}{sup -} relative to D{sub s}{sup +} {yields} K{sup +}K{sup -}{pi}{sup +}. All the results make use of data collected by the BABAR detector at the PEP-II storage rings at SLAC.
Date: August 18, 2011
Creator: Pappagallo, Marco
Object Type: Article
System: The UNT Digital Library
100-B/C Target Analyte List Development for Soil (open access)

100-B/C Target Analyte List Development for Soil

This report documents the process used to identify source area target analytes in support of the 100-B/C remedial investigation/feasibility study addendum to DOE/RL-2008-46. This report also establishes the analyte exclusion criteria applicable for 100-B/C use and the analytical methods needed to analyze the target analytes.
Date: March 18, 2010
Creator: Ovink, R.W.
Object Type: Report
System: The UNT Digital Library
Status of Monte-Carlo Event Generators (open access)

Status of Monte-Carlo Event Generators

None
Date: October 18, 2012
Creator: Hoeche, Stefan
Object Type: Article
System: The UNT Digital Library
Search for a Low-Mass Scalar Higgs Boson Decaying to a Tau Pair in Single-Photon Decays of Upsilon(1S) (open access)

Search for a Low-Mass Scalar Higgs Boson Decaying to a Tau Pair in Single-Photon Decays of Upsilon(1S)

None
Date: January 18, 2013
Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A. et al.
Object Type: Article
System: The UNT Digital Library