An imaging proton spectrometer for short-pulse laser plasma experiments (open access)

An imaging proton spectrometer for short-pulse laser plasma experiments

Ultra intense short pulse laser pulses incident on solid targets can generate energetic protons. In additions to their potentially important applications such as in cancer treatments and proton fast ignition, these protons are essential to understand the complex physics of intense laser plasma interaction. To better characterize these laser-produced protons, we designed and constructed a novel, spatially imaging proton spectrometer that will not only measure proton energy distribution with high resolution, but also provide its angular characteristics. The information obtained from this spectrometer compliments those from commonly used diagnostics including radiochromic film packs, CR39 nuclear track detectors, and non-imaging magnetic spectrometers. The basic characterizations and sample data from this instrument are presented.
Date: May 11, 2010
Creator: Chen, H.; Hazi, A.; van Maren, R.; Chen, S.; Fuchs, J.; Gauthier, M. et al.
Object Type: Article
System: The UNT Digital Library
REPORT ON QUALITATIVE VALIDATION EXPERIMENTS USING LITHIUM-ALUMINUM LAYERED DOUBLE-HYDROXIDES FOR THE REDUCTION OF ALUMINUM FROM THE WASTE TREATMENT PLANT FEEDSTOCK (open access)

REPORT ON QUALITATIVE VALIDATION EXPERIMENTS USING LITHIUM-ALUMINUM LAYERED DOUBLE-HYDROXIDES FOR THE REDUCTION OF ALUMINUM FROM THE WASTE TREATMENT PLANT FEEDSTOCK

A process for removing aluminum from tank waste simulants by adding lithium and precipitating Li-Al-dihydroxide (Lithiumhydrotalcite, [LiAl{sub 2}(OH){sub 6}]{sup +}X{sup -}) has been verified. The tests involved a double-shell tank (DST) simulant and a single-shell tank (SST) simulant. In the case of the DST simulant, the product was the anticipated Li-hydrotalcite. For the SST simulant, the product formed was primarily Li-phosphate. However, adding excess Li to the solution did result in the formation of traces of Li-hydrotalcite. The Li-hydrotalcite from the DST supernate was an easily filterable solid. After four water washes the filter cake was a fluffy white material made of < 100 {micro}m particles made of smaller spheres. These spheres are agglomerates of {approx} 5 {micro}m diameter platelets with < 1 {micro}m thickness. Chemical and mineralogical analyses of the filtrate, filter cake, and wash waters indicate a removal of 90+ wt% of the dissolved Al for the DST simulant. For the SST simulant, the main competing reaction to the formation of lithium hydrotalcite appears to be the formation of lithium phosphate. In case of the DST simulant, phosphorus co-precipitated with the hydrotalcite. This would imply the added benefit of the removal of phosphorus along with aluminum in the …
Date: May 11, 2010
Creator: Huber, H. J.; Duncan, J. B. & Cooke, G. A.
Object Type: Report
System: The UNT Digital Library
DRAINING HAZARDOUS FLUIDS DURING BUILDING 221-1F DEACTIVATION AT THE SAVANNAH RIVER SITE (open access)

DRAINING HAZARDOUS FLUIDS DURING BUILDING 221-1F DEACTIVATION AT THE SAVANNAH RIVER SITE

Several years ago, SRS completed a four year mission to decommission {approx}250 excess facilities. As part of that effort, SRS deactivated multiple facilities (e.g. Building 247-F, Naval Fuels Facility, and Building 211-F, Outside Facilities for F-Canyon) that contained extensive piping systems filled with hazardous material (e.g. nitric acid). Draining of hazardous materials from piping was successfully completed in all facilities without incident. In early 2009, the decommissioning program at SRS was restarted as a result of funding made available by the American Recovery & Reinvestment Act (ARRA). Under ARRA, draining of piping containing hazardous material was initiated in multiple facilities including Building 221-1F (or A-Line). This paper describes and reviews the draining of piping containing hazardous materials at A-Line, with emphasis on an incident involving the draining of nitric acid. The paper is intended to be a resource for engineers, planners, and project managers, who face similar draining challenges.
Date: May 11, 2010
Creator: Musall, J.
Object Type: Article
System: The UNT Digital Library
Harnessing the Chemistry of CO2 (open access)

Harnessing the Chemistry of CO2

Our research program is broadly focused on activating CO{sub 2} through the use of organic and organometallic based catalysts. Some of our methods have centered on annulation reactions of unsaturated hydrocarbons (and carbonyl substrates) to provide a diverse array of carbocycles and heterocycles. We use a combination of catalyst discovery and optimization in conjunction with classical physical organic chemistry to elucidate the key mechanistic features of the cycloaddition reactions such that the next big advances in catalyst development can be made. Key to all of our cycloaddition reactions is the use of a sterically hindered, electron donating N heterocyclic carbene (NHC) ligand, namely IPr (or SIPr), in conjunction with a low valent nickel pre-catalyst. The efficacy of this ligand is two-fold: (1) the high {delta}-donating ability of the NHC increases the nucleophilicity of the metal center which thereby facilitates interaction with the electrophilic carbonyl and (2) the steric hindrance prevents an otherwise competitive side reaction involving only the alkyne substrate. Such a system has allowed for the facile cycloaddition to prepare highly functionalized pyrones, pyridones, pyrans, as well as novel carbocycles. Importantly, all reactions proceed under extremely mild conditions (room temperature, atmospheric pressures, and short reaction times), require only catalytic …
Date: May 11, 2010
Creator: Louie, Janis
Object Type: Report
System: The UNT Digital Library
TOWARD HIGHLY SECURE AND AUTONOMIC COMPUTING SYSTEMS: A HIERARCHICAL APPROACH (open access)

TOWARD HIGHLY SECURE AND AUTONOMIC COMPUTING SYSTEMS: A HIERARCHICAL APPROACH

The overall objective of this research project is to develop novel architectural techniques as well as system software to achieve a highly secure and intrusion-tolerant computing system. Such system will be autonomous, self-adapting, introspective, with self-healing capability under the circumstances of improper operations, abnormal workloads, and malicious attacks. The scope of this research includes: (1) System-wide, unified introspection techniques for autonomic systems, (2) Secure information-flow microarchitecture, (3) Memory-centric security architecture, (4) Authentication control and its implication to security, (5) Digital right management, (5) Microarchitectural denial-of-service attacks on shared resources. During the period of the project, we developed several architectural techniques and system software for achieving a robust, secure, and reliable computing system toward our goal.
Date: May 11, 2010
Creator: Lee, Hsien-Hsin S
Object Type: Report
System: The UNT Digital Library
Influence of Incision Location on Transmitter Loss, Healing, Incision Lengths, Suture Retention, and Growth of Juvenile Chinook Salmon (open access)

Influence of Incision Location on Transmitter Loss, Healing, Incision Lengths, Suture Retention, and Growth of Juvenile Chinook Salmon

In this study, conducted by Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers, Portland District, we measured differences in survival and growth, incision openness, transmitter loss, wound healing, and erythema among abdominal incisions on the linea alba, lateral and parallel to the linea alba (muscle-cutting), and following the underlying muscle fibers (muscle-sparing). A total of 936 juvenile Chinook salmon were implanted with both Juvenile Salmon Acoustic Tracking System transmitters (0.43 g dry) and passive integrated transponder tags. Fish were held at 12°C (n = 468) or 20°C (n = 468) and examined once weekly over 98 days. We found survival and growth did not differ among incision groups or between temperature treatment groups. Incisions on the linea alba had less openness than muscle-cutting and muscle-sparing incisions during the first 14 days when fish were held at 12°C or 20°C. Transmitter loss was not different among incision locations by day 28 when fish were held at 12°C or 20°C. However, incisions on the linea alba had greater transmitter loss than muscle-cutting and muscle-sparing incisions by day 98 at 12°C. Results for wound closure and erythema differed among temperature groups. Results from our study will be used to improve …
Date: May 11, 2010
Creator: Panther, Jennifer L.; Brown, Richard S.; Gaulke, Greggory L.; Woodley, Christa M. & Deters, Katherine A.
Object Type: Report
System: The UNT Digital Library
The Energy Spectrum of Atmospheric Neutrinos between 2 and 200 TeV with the AMANDA-II Detector (open access)

The Energy Spectrum of Atmospheric Neutrinos between 2 and 200 TeV with the AMANDA-II Detector

The muon and anti-muon neutrino energy spectrum is determined from 2000-2003 AMANDA telescope data using regularised unfolding. This is the first measurement of atmospheric neutrinos in the energy range 2-200 TeV. The result is compared to different atmospheric neutrino models and it is compatible with the atmospheric neutrinos from pion and kaon decays. No significant contribution from charm hadron decays or extraterrestrial neutrinos is detected. The capabilities to improve the measurement of the neutrino spectrum with the successor experiment IceCube are discussed.
Date: May 11, 2010
Creator: Collaboration, IceCube & Abbasi, R.
Object Type: Article
System: The UNT Digital Library
Report on Electrochemical Corrosion Testing for Tank 241-AN-106 Using 2009 Sampling Campaign Grab Samples (open access)

Report on Electrochemical Corrosion Testing for Tank 241-AN-106 Using 2009 Sampling Campaign Grab Samples

Based on an ENRAF waste surface measurement taken February 1, 2009, double-shell tank (DST) 24l-AN-l06 (AN-106) contained approximately 278.98 inches (793 kgal) of waste. A zip cord measurement from the tank on February 1, 2009, indicated a settled solids layer of 9l.7 inches in height (280 kgal). The supernatant layer in February 2009, by difference, was approximately 187 inches deep (514 kgal). Laboratory results from AN-l06 February 1, 2009 (see Table 2) grab samples indicated the supernatant was below the chemistry limit that applied at the time as identified in HNF-SD-WM-TSR-006, 'Tank Farms Technical Safety Requirements', Administrative Control (AC) 5.16, 'Corrosion Mitigation Controls.' The limits have since been removed from the Technical Safety Requirements (TSR) and are captured in OSD-T-15l-00007, 'Operating Specifications for the Double-Shell Storage Tanks.' Problem evaluation request WRPS-PER-2009-0218 was submitted February 9,2009, to document the finding that the supernatant chemistry for grab samples taken from the middle and upper regions of the supernatant was noncompliant with the chemistry control limits. The lab results for the samples taken from the bottom region of the supernatant met AC 5.16 limits.
Date: May 11, 2010
Creator: Wyrwas, R. B.
Object Type: Report
System: The UNT Digital Library
Nanoheterostructure Cation Exchange: Anionic Framework Conservation (open access)

Nanoheterostructure Cation Exchange: Anionic Framework Conservation

In ionic nanocrystals the cationic sub-lattice can be replaced with a different metal ion via a fast, simple, and reversible place-exchange, allowing post-synthetic modification of the composition of the nanocrystal, while preserving its size and shape. Here, we demonstrate for the first time that during such an exchange, the anionic framework of the crystal is preserved. When applied to nanoheterostructures, this phenomenon ensures that compositional interfaces within the heterostructure are conserved throughout the transformation. For instance, a morphology composed of a CdSe nanocrystal embedded in a CdS rod (CdSe/CdS) was exchanged to a PbSe/PbS nanorod via a Cu2Se/Cu2S structure. During every exchange cycle, the seed size and position within the nanorod were preserved, as evident by excitonic features, Z-contrast imaging, and elemental line-scans. Anionic framework conservation extends the domain of cation exchange to the design of more complex and unique nanostructures.
Date: May 11, 2010
Creator: Jain, Prashant K.; Amirav, Lilac; Aloni, Shaul & Alivisatos, A. Paul
Object Type: Article
System: The UNT Digital Library
Backscatter measurements for NIF ignition targets (open access)

Backscatter measurements for NIF ignition targets

None
Date: May 11, 2010
Creator: Moody, J. D.; Michel, P. A.; Bond, E.; Datte, P.; Krauter, K.; Glenzer, S. H. et al.
Object Type: Article
System: The UNT Digital Library
Application Acceleration on Current and Future Cray Platforms (open access)

Application Acceleration on Current and Future Cray Platforms

None
Date: May 11, 2010
Creator: Koniges, A.; Preissl, R.; Kim, J.; Eder, D.; Fisher, A.; Masters, N. et al.
Object Type: Article
System: The UNT Digital Library
Characterizing high energy spectra of NIF ignition hohlraums using a differentially filtered high energy multi-pinhole X-ray imager (open access)

Characterizing high energy spectra of NIF ignition hohlraums using a differentially filtered high energy multi-pinhole X-ray imager

Understanding hot electron distributions generated inside hohlraums is important to the ignition campaign for controlling implosion symmetry and sources of preheat. While direct imaging of hot electrons is difficult, their spatial distribution and spectrum can be deduced by detecting high energy x-rays generated as they interact with the target materials. We used an array of 18 pinholes, with four independent filter combinations, to image entire hohlraums with a magnification of 0.87x during the hohlraum energetics campaign on NIF. Comparing our results with hohlraum simulations indicates that the characteristic 30 keV hot electrons are mainly generated from backscattered laser plasma interactions rather than from hohlraum hydrodynamics.
Date: May 11, 2010
Creator: Park, H.; Dewald, E. D.; Glenzer, S.; Kalantar, D. H.; Kilkenny, J. D.; MacGowan, B. J. et al.
Object Type: Article
System: The UNT Digital Library