Interferometric adaptive optics for the National Ignition Facility (open access)

Interferometric adaptive optics for the National Ignition Facility

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Date: January 14, 2010
Creator: Baker, K.; Homoelle, D.; Stappaerts, E.; Siders, C. & Barty, C.
Object Type: Article
System: The UNT Digital Library
The E166 experiment: Development of an Undulator-Based Polarized Positron Source for the International Linear Collider (open access)

The E166 experiment: Development of an Undulator-Based Polarized Positron Source for the International Linear Collider

A longitudinal polarized positron beam is foreseen for the international linear collider (ILC). A proof-of-principle experiment has been performed in the final focus test beam at SLAC to demonstrate the production of polarized positrons for implementation at the ILC. The E166 experiment uses a 1 m long helical undulator in a 46.6 GeV electron beam to produce a few MeV photons with a high degree of circular polarization. These photons are then converted in a thin target to generate longitudinally polarized e{sup +} and e{sup -}. The positron polarization is measured using a Compton transmission polarimeter. The data analysis has shown asymmetries in the expected vicinity of 3.4% and {approx}1% for photons and positrons respectively and the expected positron longitudinal polarization is covering a range from 50% to 90%. The full exploitation of the physics potential of an international linear collider (ILC) will require the development of polarized positron beams. Having both e{sup +} and e{sup -} beams polarized will provide new insight into structures of couplings and thus give access to physics beyond the standard model [1]. The concept for a polarized positron source is based on circularly polarized photon sources. These photons are then converted to longitudinally polarized …
Date: November 14, 2011
Creator: Kovermann, J.; Stahl, A.; Mikhailichenko, A. A.; Scott, D.; Moortgat-Pick, G. A.; Gharibyan, V. et al.
Object Type: Article
System: The UNT Digital Library
PILOT-SCALE FIELD VALIDATION OF THE LONG ELECTRODE ELECTRICAL RESISTIVITY TOMOGRAPHY METHOD (open access)

PILOT-SCALE FIELD VALIDATION OF THE LONG ELECTRODE ELECTRICAL RESISTIVITY TOMOGRAPHY METHOD

Field validation for the long electrode electrical resistivity tomography (LE-ERT) method was attempted in order to demonstrate the performance of the technique in imaging a simple buried target. The experiment was an approximately 1/17 scale mock-up of a region encompassing a buried nuclear waste tank on the Hanford site. The target of focus was constructed by manually forming a simulated plume within the vadose zone using a tank waste simulant. The LE-ERT results were compared to ERT using conventional point electrodes on the surface and buried within the survey domain. Using a pole-pole array, both point and long electrode imaging techniques identified the lateral extents of the pre-formed plume with reasonable fidelity, but the LE-ERT was handicapped in reconstructing the vertical boundaries. The pole-dipole and dipole-dipole arrays were also tested with the LE-ERT method and were shown to have the least favorable target properties, including the position of the reconstructed plume relative to the known plume and the intensity of false positive targets. The poor performance of the pole-dipole and dipole-dipole arrays was attributed to an inexhaustive and non-optimal coverage of data at key electrodes, as well as an increased noise for electrode combinations with high geometric factors. However, when …
Date: July 14, 2011
Creator: Rucker, D. F.; Loke, M. H.; Crook, N. & Glaser, D. R.
Object Type: Article
System: The UNT Digital Library
SPE2 Far-field Seismic Data Quicklook (open access)

SPE2 Far-field Seismic Data Quicklook

The purpose of this report is to provide a brief overview of the far-field seismic data collected by the array of instruments (Figures 1 and 2) deployed by the Source Physics experiment for shots 1 (roughly 100 kg TNT equivalent at a depth of 60 m) and shot 2, (roughly 2000 kg TNT equivalent at a depth of 45 m). 'Far-field' is taken to refer to instruments in the zone of purely elastic response at distances of 100 m or greater. The primary focus is data from the main instrument array and hence data from other groups is not considered. Infrasound data is not addressed nor any remote sensing data. Data processing was done at LLNL in parallel with the effort at UNR. Raw reftek data was sent via hard disk from NsTec. Reftek data was converted to SEGY and then to SAC format. Data files were renamed according to station and channel information. Reftek logs were reviewed. These data have been reviewed for consistency with the UNR data on the server. The primary goal was quality check and a summary is provided in Tables 1 and 2.
Date: February 14, 2012
Creator: Mellors, R. J.; Harben, P.; Ford, S.; Walter, W. R.; Hauk, T.; Ruppert, S. et al.
Object Type: Report
System: The UNT Digital Library
Verification for Portability, Scalability, and Grokkability (open access)

Verification for Portability, Scalability, and Grokkability

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Date: July 14, 2010
Creator: Humphrey, Alan; Derrick, Christopher; Tibbitts, Beth; Vo, Anh; Vakkalanka, Sarvani; Gopalakrishnan, Ganesh et al.
Object Type: Article
System: The UNT Digital Library
Project Final Report: Ubiquitous Computing and Monitoring System (UCoMS) for Discovery and Management of Energy Resources (open access)

Project Final Report: Ubiquitous Computing and Monitoring System (UCoMS) for Discovery and Management of Energy Resources

The UCoMS research cluster has spearheaded three research areas since August 2004, including wireless and sensor networks, Grid computing, and petroleum applications. The primary goals of UCoMS research are three-fold: (1) creating new knowledge to push forward the technology forefronts on pertinent research on the computing and monitoring aspects of energy resource management, (2) developing and disseminating software codes and toolkits for the research community and the public, and (3) establishing system prototypes and testbeds for evaluating innovative techniques and methods. Substantial progress and diverse accomplishment have been made by research investigators in their respective areas of expertise cooperatively on such topics as sensors and sensor networks, wireless communication and systems, computational Grids, particularly relevant to petroleum applications.
Date: July 14, 2012
Creator: Tzeng, Nian-Feng; White, Christopher D. & Moreman, Douglas
Object Type: Report
System: The UNT Digital Library
Molecular Dynamics Simulations of Classical Stopping Power (open access)

Molecular Dynamics Simulations of Classical Stopping Power

None
Date: August 14, 2013
Creator: Grabowski, Paul E.; Surh, Michael P.; Richards, David F.; Langdon, A. Bruce; Graziani, Frank R. & Murillo, Michael S.
Object Type: Article
System: The UNT Digital Library
Investigating Chemical and Molecular Changes in Uranium Oxyfluoride Particles using NanoSIMS and Micro-Raman Spectroscopy (open access)

Investigating Chemical and Molecular Changes in Uranium Oxyfluoride Particles using NanoSIMS and Micro-Raman Spectroscopy

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Date: September 14, 2010
Creator: Kips, R.; Kristo, M. J.; Crowhurst, J.; Hutcheon, I. D.; Stefaniak, E. A. & Aregbe, Y.
Object Type: Article
System: The UNT Digital Library
MANAGING ENGINEERING ACTIVITIES FOR THE PLATEAU REMEDIATION CONTRACT - HANFORD (open access)

MANAGING ENGINEERING ACTIVITIES FOR THE PLATEAU REMEDIATION CONTRACT - HANFORD

In 2008, the primary Hanford clean-up contract transitioned to the CH2MHill Plateau Remediation Company (CHPRC). Prior to transition, Engineering resources assigned to remediation/Decontamination and Decommissioning (D&D) activities were a part of a centralized engineering organization and matrixed to the performing projects. Following transition, these resources were reassigned directly to the performing project, with a loose matrix through a smaller Central Engineering (CE) organization. The smaller (10 FTE) central organization has retained responsibility for the overall technical quality of engineering for the CHPRC, but no longer performs staffing and personnel functions. As the organization has matured, there are lessons learned that can be shared with other organizations going through or contemplating performing a similar change. Benefits that have been seen from the CHPRC CE organization structure include the following: (1) Staff are closely aligned with the 'Project/facility' that they are assigned to support; (2) Engineering priorities are managed to be consistent with the 'Project/facility' priorities; (3) Individual Engineering managers are accountable for identifying staffing needs and the filling of staffing positions; (4) Budget priorities are managed within the local organization structure; (5) Rather than being considered a 'functional' organization, engineering is considered a part of a line, direct funded organization; (6) …
Date: January 14, 2011
Creator: Kronvall, C. M.
Object Type: Article
System: The UNT Digital Library
Quantitative Analysis of Clustered DNA Damages Induced by Silicon Beams of Different Kinetic Energy (open access)

Quantitative Analysis of Clustered DNA Damages Induced by Silicon Beams of Different Kinetic Energy

Humans may b exposed to highly energetic charged particle radiation as a result of medical treatments, occupational activitie or accidental events. In recent years, our increasing presence and burgeoning interest in space exploration beyond low Earth orbit has led to a large increase in the research of the biological effects ofcharged particle radiation typical of that encountered in the space radiation environment. The study of the effects of these types of radiation qualities in terms ofDNA damage induction and repair is fundamental to understand mechanisms both underlying their greater biological effectiveness as we)) as the short and long term risks of health effects such as carcinogenesis, degen rative diseases and premature aging. Charged particle radiation induces a variety of DNA alterations, notably bistranded clustered damages, defined as two or more closely-opposed strand break , oxidized bases or abasic sites within a few helical turns. The induction of such highly complex DNA damage enhances the probability of incorrect or incomplete repair and thus constitutes greater potential for genomic instability, cell death and transformation.
Date: May 14, 2013
Creator: Keszenman, D. J.; Bennett, P. V.; Sutherland, B. M. & Wilson, P. F.
Object Type: Article
System: The UNT Digital Library
Characteristics of Undoped and Europium-doped SrI2 Scintillator Detectors (open access)

Characteristics of Undoped and Europium-doped SrI2 Scintillator Detectors

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Date: November 14, 2011
Creator: Sturm, Benjamin W.; Cherepy, Nerine J.; Drury, Owen B.; Thelin, Peter A.; Fisher, Scott E.; Payne, Stephen A. et al.
Object Type: Article
System: The UNT Digital Library
Photoelectrochemistry, Electronic Structure, and Bandgap Sizes of Semiconducting Cu(I)-Niobates and Cu(I)-Tantalates (open access)

Photoelectrochemistry, Electronic Structure, and Bandgap Sizes of Semiconducting Cu(I)-Niobates and Cu(I)-Tantalates

Semiconducting metal-oxides have remained of intense research interest owing to their potential for achieving efficient solar-driven photocatalytic reactions in aqueous solutions that occur as a result of their bandgap excitation. The photocatalytic reduction of water or carbon dioxide to generate hydrogen or hydrocarbon fuels, respectively, can be driven on p-type (photocathodic) electrodes with suitable band energies. However, metal-oxide semiconductors are typically difficult to dope as p-type with a high mobility of carriers. The supported research led to the discovery of new p-type Cu(I)-niobate and Cu(I)-tantalate film electrodes that can be prepared on FTO glass. New high-purity flux syntheses and the full structural determination of several Cu(I)-containing niobates and tantalates have been completed, as well as new investigations of their optical and photoelectrochemical properties and electronic structures via density-functional theory calculations. For example, CuNbO3, Cu5Ta11O30 and CuNb3O8 were prepared in high purity and their structures were characterized by both single-crystal and powder X-ray diffraction techniques. These two classes of Cu(I)-containing compounds exhibit optical bandgap sizes ranging from ~1.3 eV to ~2.6 eV. Photoelectrochemical measurements of these compounds show strong photon-driven cathodic currents that confirm the p-type semiconductor behavior of CuNbO3, CuNb3O8, and Cu5Ta11O30. Incident-photon-to-current efficiencies are measured that approach greater than …
Date: November 14, 2013
Creator: Maggard, Paul A.
Object Type: Report
System: The UNT Digital Library
Aerosol Absorption and Scattering Measurements: Field Measuremnets and Laboratory Characterizations. (open access)

Aerosol Absorption and Scattering Measurements: Field Measuremnets and Laboratory Characterizations.

The objective of this report is to determine the overall impact of atmospheric aerosols on radioactive balance.
Date: December 14, 2011
Creator: Marley, Nancy A. & Gaffney, Jeffrey S.
Object Type: Report
System: The UNT Digital Library