States

Fast MAP Search for Compact Additive Tree Ensembles (CATE) (open access)

Fast MAP Search for Compact Additive Tree Ensembles (CATE)

None
Date: March 21, 2013
Creator: Prenger, R J; Chen, B Y; Marlatt, T L & Merl, D M
Object Type: Report
System: The UNT Digital Library
Interaction-Region Design Options for a Linac-Ring LHeC (open access)

Interaction-Region Design Options for a Linac-Ring LHeC

The interaction-region design for a linac-ring electron-proton collider based on the LHC ('LR-LHeC') poses numerous challenges related to collision scheme, synchrotron radiation, aperture, magnet technology, and optics. We report a first assessment and various options.
Date: June 21, 2012
Creator: Zimmermann, Frank; /CERN; Bettoni, Simona; /CERN; Bruning, Oliver; /CERN et al.
Object Type: Article
System: The UNT Digital Library
Weighting Factors for the Commercial Building Prototypes Used in the Development of ANSI/ASHRAE/IESNA Standard 90.1-2010 (open access)

Weighting Factors for the Commercial Building Prototypes Used in the Development of ANSI/ASHRAE/IESNA Standard 90.1-2010

Detailed construction data from the McGraw Hill Construction Database was used to develop construction weights by climate zones for use with DOE Benchmark Buildings and for the ASHRAE Standard 90.1-2010 development. These construction weights were applied to energy savings estimates from simulation of the benchmark buildings to establish weighted national energy savings.
Date: January 21, 2010
Creator: Jarnagin, Ronald E. & Bandyopadhyay, Gopal K.
Object Type: Report
System: The UNT Digital Library
Ni-Si Alloys for the S-I Reactor-Hydrogen Production Process Interface (open access)

Ni-Si Alloys for the S-I Reactor-Hydrogen Production Process Interface

The overall goal of this project was to develop Ni-Si alloys for use in vessels to contain hot, pressurized sulfuric acid. The application was to be in the decomposition loop of the thermochemical cycle for production of hydrogen.
Date: January 21, 2010
Creator: Newkirk, Joseph W. & Brow, Richard K.
Object Type: Report
System: The UNT Digital Library
AUTOMATING GROUNDWATER SAMPLING AT HANFORD THE NEXT STEP (open access)

AUTOMATING GROUNDWATER SAMPLING AT HANFORD THE NEXT STEP

Historically, the groundwater monitoring activities at the Department of Energy's Hanford Site in southeastern Washington State have been very "people intensive." Approximately 1500 wells are sampled each year by field personnel or "samplers." These individuals have been issued pre-printed forms showing information about the well(s) for a particular sampling evolution. This information is taken from 2 official electronic databases: the Hanford Well information System (HWIS) and the Hanford Environmental Information System (HEIS). The samplers used these hardcopy forms to document the groundwater samples and well water-levels. After recording the entries in the field, the samplers turned the forms in at the end of the day and other personnel posted the collected information onto a spreadsheet that was then printed and included in a log book. The log book was then used to make manual entries of the new information into the software application(s) for the HEIS and HWIS databases. A pilot project for automating this extremely tedious process was lauched in 2008. Initially, the automation was focused on water-level measurements. Now, the effort is being extended to automate the meta-data associated with collecting groundwater samples. The project allowed electronic forms produced in the field by samplers to be used in …
Date: January 21, 2010
Creator: CW, CONNELL; SF, CONLEY; RD, HILDEBRAND; DE, CUNNINGHAM; R_D_Doug_Hildebrand@rl.gov & DeVon_E_Cunningham@rl.gov
Object Type: Article
System: The UNT Digital Library
Extracellular oxidative metabolism of wood decay fungi (open access)

Extracellular oxidative metabolism of wood decay fungi

Substantial progress has been made toward understanding the fundamental physiology and genetics of wood decay fungi, microbes that are capable of degrading all major components of plant cell walls. Efficient utilization of lignocellulosic biomass has been hampered in part by limitations in our understanding of enzymatic mechanisms of plant cell wall degradation. This is particularly true of woody substrates where accessibility and high lignin content substantially complicate enzymatic 'deconstruction'. The interdisciplinary research has illuminated enzymatic mechanisms essential for the conversion of lignocellulosics to simple carbohydrates and other small molecular weight products. Progress was in large part dependent on substantial collaborations with the Department of Energy's Joint Genome Institute (JGI) in Walnut Creek and Los Alamos, as well as the Catholic University, Santiago, Chile, the Royal Institute of Technology, Stockholm, the University of Minnesota, St. Paul, and colleagues at the University of Wisconsin and the Forest Products Laboratory. Early accomplishments focused on the development of experimental tools (2, 7, 22, 24-26, 32) and characterization of individual genes and enzymes (1, 3-5, 8, 9, 11, 14, 15, 17, 18, 23, 27, 33). In 2004, the genome of the most intensively studied lignin-degrading fungus, Phanerochaete chrysosporium, was published (21). This milestone lead to …
Date: April 21, 2010
Creator: Cullen, Daniel
Object Type: Report
System: The UNT Digital Library
Application of Ensemble Sensitivity Analysis to Observation Targeting for Short-term Wind Speed Forecasting (open access)

Application of Ensemble Sensitivity Analysis to Observation Targeting for Short-term Wind Speed Forecasting

The operators of electrical grids, sometimes referred to as Balancing Authorities (BA), typically make critical decisions on how to most reliably and economically balance electrical load and generation in time frames ranging from a few minutes to six hours ahead. At higher levels of wind power generation, there is an increasing need to improve the accuracy of 0- to 6-hour ahead wind power forecasts. Forecasts on this time scale have typically been strongly dependent on short-term trends indicated by the time series of power production and meteorological data from a wind farm. Additional input information is often available from the output of Numerical Weather Prediction (NWP) models and occasionally from off-site meteorological towers in the region surrounding the wind generation facility. A widely proposed approach to improve short-term forecasts is the deployment of off-site meteorological towers at locations upstream from the wind generation facility in order to sense approaching wind perturbations. While conceptually appealing, it turns out that, in practice, it is often very difficult to derive significant benefit in forecast performance from this approach. The difficulty is rooted in the fact that the type, scale, and amplitude of the processes controlling wind variability at a site change from day …
Date: February 21, 2010
Creator: Zack, J; Natenberg, E; Young, S; Manobianco, J & Kamath, C
Object Type: Report
System: The UNT Digital Library
Flammability Analysis For Actinide Oxides Packaged In 9975 Shipping Containers (open access)

Flammability Analysis For Actinide Oxides Packaged In 9975 Shipping Containers

Packaging options are evaluated for compliance with safety requirements for shipment of mixed actinide oxides packaged in a 9975 Primary Containment Vessel (PCV). Radiolytic gas generation rates, PCV internal gas pressures, and shipping windows (times to reach unacceptable gas compositions or pressures after closure of the PCV) are calculated for shipment of a 9975 PCV containing a plastic bottle filled with plutonium and uranium oxides with a selected isotopic composition. G-values for radiolytic hydrogen generation from adsorbed moisture are estimated from the results of gas generation tests for plutonium oxide and uranium oxide doped with curium-244. The radiolytic generation of hydrogen from the plastic bottle is calculated using a geometric model for alpha particle deposition in the bottle wall. The temperature of the PCV during shipment is estimated from the results of finite element heat transfer analyses.
Date: March 21, 2013
Creator: Laurinat, James E.; Askew, Neal M. & Hensel, Steve J.
Object Type: Article
System: The UNT Digital Library

Durability of Poly (Methyl Methacrylate) Lenses Used in Concentrating Photovoltaics

This presentation reports the findings of NREL's screen test to characterize the durability of poly (methyl methacrylate) lenses used in concentrated photovoltaics.
Date: October 21, 2010
Creator: Miller, D.; Gedvilas, L.; To, B.; Kennedy, C. & Kurtz, S.
Object Type: Presentation
System: The UNT Digital Library
BOUT Simulations of Edge Turbulence in the DIII-D Tokamak (open access)

BOUT Simulations of Edge Turbulence in the DIII-D Tokamak

None
Date: March 21, 2012
Creator: Cohen, B. I.; Umansky, M.; Makowski, M.; Nevins, W. M.; Boedo, J.; Rudakov, D. et al.
Object Type: Article
System: The UNT Digital Library
DHS-STEM Summer Internship Report (open access)

DHS-STEM Summer Internship Report

None
Date: August 21, 2013
Creator: Harrison, S E
Object Type: Report
System: The UNT Digital Library
Key Physical Mechanisms in Nanostructured Solar Cells (open access)

Key Physical Mechanisms in Nanostructured Solar Cells

The objective of the project was to study both theoretically and experimentally the excitation, recombination and transport properties required for nanostructured solar cells to deliver energy conversion efficiencies well in excess of conventional limits. These objectives were met by concentrating on three key areas, namely, investigation of physical mechanisms present in nanostructured solar cells, characterization of loss mechanisms in nanostructured solar cells and determining the properties required of nanostructured solar cells in order to achieve high efficiency and the design implications.
Date: July 21, 2010
Creator: Bremner, Stephan
Object Type: Report
System: The UNT Digital Library
Status of the Neutralized Drift Compression Experiment (NDCX-II) (open access)

Status of the Neutralized Drift Compression Experiment (NDCX-II)

The Neutralized Drift Compression Experiment (NDCX-II) is an 11 M$ induction accelerator project currently in construction at Lawrence Berkeley National Laboratory for warm dense matter (WDM) experiments investigating the interaction of ion beams with matter at elevated temperature and pressure. The machine consists of a lithium injector, induction accelerator cells, diagnostic cells, a neutralized drift compression line, a final focus solenoid, and a target chamber. The induction cells and some of the pulsed power systems have been reused from the decommissioned Advanced Test Accelerator at Lawrence Livermore National Laboratory after refurbishment and modification. The machine relies on a sequence of acceleration waveforms to longitudinally compress the initial ion pulse from 600 ns to less than 1 ns in {approx} 12 m. Radial confinement of the beam is achieved with 2.5 T pulsed solenoids. In the initial hardware configuration, 50 nC of Li{sup +} will be accelerated to 1.25 MeV and allowed to drift-compress to a peak current of {approx}40 A. The project started in the summer of 2009. Construction of the accelerator will be completed in the fall of 2011 and will provide a worldwide unique opportunity for ion-driven warm dense matter experiments as well as research related to novel …
Date: April 21, 2011
Creator: Waldron, W. L. & Kwan, J. W.
Object Type: Article
System: The UNT Digital Library
THE EFFECT OF VARIOUS DETECTOR GEOMETRIES ON THE PERFORMANCE OF CZT USING ONE CRYSTAL (open access)

THE EFFECT OF VARIOUS DETECTOR GEOMETRIES ON THE PERFORMANCE OF CZT USING ONE CRYSTAL

CdZnTe (CZT) continues to be a major thrust interest mainly due to its potential application as a room temperature radiation detector. The performance of CZT detectors is directly related to the charge collection ability which can be affected by the configuration of the electrical contact. The charge collection efficiency is determined in part by the specific geometry of the anode contact which serves as the readout electrode. In this report, contact geometries including single pixel, planar, coplanar, and dual anode will be systematically explored by comparing the performance efficiencies of the detector using both low and high energy gamma rays. To help eliminate the effect of crystal quality variations, the contact geometries were fabricated on the same crystal detector with minimal polishing between contact placements.
Date: June 21, 2011
Creator: Washington, A.; Duff, M. & Teague, L.
Object Type: Article
System: The UNT Digital Library
Evaluation of LLNL's Nuclear Accident Dosimeters at the CALIBAN Reactor September 2010 (open access)

Evaluation of LLNL's Nuclear Accident Dosimeters at the CALIBAN Reactor September 2010

The Lawrence Livermore National Laboratory uses neutron activation elements in a Panasonic TLD holder as a personnel nuclear accident dosimeter (PNAD). The LLNL PNAD has periodically been tested using a Cf-252 neutron source, however until 2009, it was more than 25 years since the PNAD has been tested against a source of neutrons that arise from a reactor generated neutron spectrum that simulates a criticality. In October 2009, LLNL participated in an intercomparison of nuclear accident dosimeters at the CEA Valduc Silene reactor (Hickman, et.al. 2010). In September 2010, LLNL participated in a second intercomparison of nuclear accident dosimeters at CEA Valduc. The reactor generated neutron irradiations for the 2010 exercise were performed at the Caliban reactor. The Caliban results are described in this report. The procedure for measuring the nuclear accident dosimeters in the event of an accident has a solid foundation based on many experimental results and comparisons. The entire process, from receiving the activated NADs to collecting and storing them after counting was executed successfully in a field based operation. Under normal conditions at LLNL, detectors are ready and available 24/7 to perform the necessary measurement of nuclear accident components. Likewise LLNL maintains processing laboratories that are …
Date: June 21, 2011
Creator: Hickman, D P; Wysong, A R; Heinrichs, D P; Wong, C T; Merritt, M J; Topper, J D et al.
Object Type: Report
System: The UNT Digital Library
Characterization of Group V Dubnium Homologs on DGA Extraction Chromatography Resin from Nitric and Hydrofluoric Acid Matrices (open access)

Characterization of Group V Dubnium Homologs on DGA Extraction Chromatography Resin from Nitric and Hydrofluoric Acid Matrices

Studies of the chemical properties of superheavy elements (SHE) pose interesting challenges due to their short half-lives and low production rates. Chemical systems must have extremely fast kinetics, fast enough kinetics to be able to examine the chemical properties of interest before the SHE decays to another nuclide. To achieve chemistry on such time scales, the chemical system must also be easily automated. Most importantly however, a chemical system must be developed which provides suitable separation and kinetics before an on-line study of a SHE can be performed. Relativistic effects make studying the chemical properties of SHEs interesting due to the impact these effects could have on the SHEs chemical properties. Relativistic effects arise when the velocity of the s orbital electrons approach the speed of light. As this velocity increases, the Bohr radius of the inner electron orbitals decreases and there is an increase in the particles mass. This contraction results in a destabilization of the energy of the outer d and f electron orbitals (5f and 6d in the case of SHE), which can cause these to expand due to their increased shielding from the nuclear charge. Another relativistic effect is the spin-orbit splitting for p, d, and …
Date: February 21, 2012
Creator: Despotopulos, J D & Sudowe, R
Object Type: Report
System: The UNT Digital Library
Search for Pair Production of First Or Second Generation Leptoquarks in Proton-Proton Collisions at sqrt(s)=7 TeV using the ATLAS detector at the LHC (open access)
Mesoscale Simulations of a Wind Ramping Event for Wind Energy Prediction (open access)

Mesoscale Simulations of a Wind Ramping Event for Wind Energy Prediction

Ramping events, or rapid changes of wind speed and wind direction over a short period of time, present challenges to power grid operators in regions with significant penetrations of wind energy in the power grid portfolio. Improved predictions of wind power availability require adequate predictions of the timing of ramping events. For the ramping event investigated here, the Weather Research and Forecasting (WRF) model was run at three horizontal resolutions in 'mesoscale' mode: 8100m, 2700m, and 900m. Two Planetary Boundary Layer (PBL) schemes, the Yonsei University (YSU) and Mellor-Yamada-Janjic (MYJ) schemes, were run at each resolution as well. Simulations were not 'tuned' with nuanced choices of vertical resolution or tuning parameters so that these simulations may be considered 'out-of-the-box' tests of a numerical weather prediction code. Simulations are compared with sodar observations during a wind ramping event at a 'West Coast North America' wind farm. Despite differences in the boundary-layer schemes, no significant differences were observed in the abilities of the schemes to capture the timing of the ramping event. As collaborators have identified, the boundary conditions of these simulations probably dominate the physics of the simulations. They suggest that future investigations into characterization of ramping events employ ensembles of …
Date: September 21, 2011
Creator: Rhodes, M & Lundquist, J K
Object Type: Report
System: The UNT Digital Library
Commnity Petascale Project for Accelerator Science And Simulation: Advancing Computational Science for Future Accelerators And Accelerator Technologies (open access)

Commnity Petascale Project for Accelerator Science And Simulation: Advancing Computational Science for Future Accelerators And Accelerator Technologies

The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.
Date: October 21, 2011
Creator: Spentzouris, Panagiotis; /Fermilab; Cary, John; /Tech-X, Boulder; Mcinnes, Lois Curfman; /Argonne et al.
Object Type: Article
System: The UNT Digital Library
An Equivalent Circuit Model and Power Calculations for the APS SPX Crab Cavities. (open access)

An Equivalent Circuit Model and Power Calculations for the APS SPX Crab Cavities.

An equivalent parallel resistor-inductor-capacitor (RLC) circuit with beam loading for a polarized TM110 dipole-mode cavity is developed and minimum radio-frequency (rf) generator requirements are calculated for the Advanced Photon Source (APS) short-pulse x-ray (SPX) superconducting rf (SRF) crab cavities. A beam-loaded circuit model for polarized TM110 mode crab cavities was derived. The single-cavity minimum steady-state required generator power has been determined for the APS SPX crab cavities for a storage ring current of 200mA DC current as a function of external Q for various vertical offsets including beam tilt and uncontrollable detuning. Calculations to aid machine protection considerations were given.
Date: March 21, 2012
Creator: Berenc, T.
Object Type: Report
System: The UNT Digital Library
Molecular-Level Design of Heterogeneous Chiral Catalysis (open access)

Molecular-Level Design of Heterogeneous Chiral Catalysis

The following is a proposal to continue our multi-institutional research on heterogeneous chiral catalysis. Our team combines the use of surface-sensitive analytical techniques for the characterization of model systems with quantum and statistical mechanical calculations to interpret experimental data and guide the design of future research. Our investigation focuses on the interrelation among the three main mechanisms by which enantioselectivity can be bestowed to heterogeneous catalysts, namely: (1) by templating chirality via the adsorption of chiral supramolecular assemblies, (2) by using chiral modifiers capable of forming chiral complexes with the reactant and force enantioselective surface reactions, and (3) by forming naturally chiral surfaces using imprinting chiral agents. Individually, the members of our team are leaders in these various aspects of chiral catalysis, but the present program provides the vehicle to generate and exploit the synergies necessary to address the problem in a comprehensive manner. Our initial work has advanced the methodology needed for these studies, including an enantioselective titration procedure to identify surface chiral sites, infrared spectroscopy in situ at the interface between gases or liquids and solids to mimic realistic catalytic conditions, and DFT and Monte Carlo algorithms to simulate and understand chirality on surfaces. The next step, to …
Date: March 21, 2012
Creator: Zaera, Francisco
Object Type: Report
System: The UNT Digital Library
Final Technical Report (open access)

Final Technical Report

This report summarizes many of the projects, and lists all of the publications and persons trained with support from the grant.
Date: April 21, 2011
Creator: Herrin, David L.
Object Type: Report
System: The UNT Digital Library
Longitudinal Beam Tuning at FACET (open access)

Longitudinal Beam Tuning at FACET

None
Date: November 21, 2012
Creator: Decker, F.-J.; Lipkowitz, N.; Sheppard, J.; Weathersby, S.P.; Wienands, U.; Woodley, M. et al.
Object Type: Article
System: The UNT Digital Library
Recommendations for a Static Cosmic Ray Shield for Enriched Germanium Detectors (open access)

Recommendations for a Static Cosmic Ray Shield for Enriched Germanium Detectors

This document provides a detailed study of cost and materials that could be used to shield the detector material of the international Tonne-scale germanium neutrinoless double-beta decay experiment from hadronic particles from cosmic ray showers at the Earth's surface. This work was motivated by the need for a shield that minimizes activation of the enriched germanium during storage; in particular, when the detector material is being worked on at the detector manufacturer's facility. This work considers two options for shielding the detector material from cosmic ray particles. One option is to use a pre-existing structure already located near the detector manufacturer, such as Canberra Industries in Meriden, Connecticut. The other option is to build a shield onsite at a detector manufacturer's site. This paper presents a cost and efficiency analysis of such construction.
Date: September 21, 2011
Creator: Aguayo Navarrete, Estanislao; Orrell, John L.; Ankney, Austin S. & Berguson, Timothy J.
Object Type: Report
System: The UNT Digital Library