Corrosion-resistant multilayer coatings for the 28-75 nm wavelength region (open access)

Corrosion-resistant multilayer coatings for the 28-75 nm wavelength region

Corrosion has prevented use of SiC/Mg multilayers in applications requiring good lifetime stability. We have developed Al-based barrier layers that dramatically reduce corrosion, while preserving high reflectance and low stress. The aforementioned advances may enable the implementation of corrosion-resistant, high-performance SiC/Mg coatings in the 28-75 nm region in applications such as tabletop EUV/soft x-ray laser sources and solar physics telescopes. Further study and optimization of corrosion barrier structures and coating designs is underway.
Date: November 8, 2011
Creator: Soufli, R.; Fernandez-Perea, Monica & Al, E. T.
Object Type: Article
System: The UNT Digital Library
Efficiency Enhancement in a Tapered Free Electron Laser By Varying the Electron Beam Radius (open access)

Efficiency Enhancement in a Tapered Free Electron Laser By Varying the Electron Beam Radius

None
Date: October 8, 2013
Creator: Jiao, Y.; Wu, J. & Qin, Q.
Object Type: Article
System: The UNT Digital Library
INSTALLATION OF BUBBLERS IN THE SAVANNAH RIVER SITED DEFENSE WASTE PROCESSING FACILITY MELTER (open access)

INSTALLATION OF BUBBLERS IN THE SAVANNAH RIVER SITED DEFENSE WASTE PROCESSING FACILITY MELTER

Savannah River Remediation (SRR) LLC assumed the liquid waste contract at the Savannah River Site (SRS) in the summer of 2009. The main contractual agreement was to close 22 High Level Waste (HLW) tanks in eight years. To achieve this aggressive commitment, faster waste processing throughout the SRS liquid waste facilities will be required. Part of the approach to achieve faster waste processing is to increase the canister production rate of the Defense Waste Processing Facility (DWPF) from approximately 200 canisters filled with radioactive waste glass per year to 400 canisters per year. To reach this rate for melter throughput, four bubblers were installed in the DWPF Melter in the late summer of 2010. This effort required collaboration between SRR, SRR critical subcontractor EnergySolutions, and Savannah River Nuclear Solutions, including the Savannah River National Laboratory (SRNL). The tasks included design and fabrication of the bubblers and related equipment, testing of the bubblers for various technical issues, the actual installation of the bubblers and related equipment, and the initial successful operation of the bubblers in the DWPF Melter.
Date: December 8, 2010
Creator: Smith, M. & Iverson, D.
Object Type: Article
System: The UNT Digital Library
Monte Carlo Simulation of a Coded Aperture Thermal Neutron Camera (open access)

Monte Carlo Simulation of a Coded Aperture Thermal Neutron Camera

N/A
Date: May 8, 2011
Creator: I., Dioszegi; Salwen, C. & and Forman, I.
Object Type: Article
System: The UNT Digital Library
Sample Results From The Next Generation Solvent Program Real Waste Extraction-Scrub-Strip Testing (open access)

Sample Results From The Next Generation Solvent Program Real Waste Extraction-Scrub-Strip Testing

Savannah River National Laboratory (SRNL) performed multiple Extraction-Scrub-Strip (ESS) testing using real waste solutions, and three Next Generation Solvent (NGS) variations, which included radiologically clean pure NGS, a blend of radiologically clean NGS and radiologically clean BOBCalixC6 (NGS-MCU), and a blend of radiologically clean NGS and radiologically contaminated BOBCalixC6 from the MCU Solvent system. The results from the tests indicate that both the NGS and the NGS-MCU blend exhibit adequate extraction, scrub and strip behavior.
Date: August 8, 2013
Creator: Peters, T. B. & Washington, A. L. II
Object Type: Report
System: The UNT Digital Library
Multi-Dimensional Optimization of a Tapered Free Electron Laser (open access)

Multi-Dimensional Optimization of a Tapered Free Electron Laser

None
Date: October 8, 2013
Creator: Jiao, Y.; Wu, J. & Qin, Q.
Object Type: Article
System: The UNT Digital Library
Bioinspired Molecular Co-Catalysts Bonded to a Silicon Photocathode for Solar Hydrogen Evolution (open access)

Bioinspired Molecular Co-Catalysts Bonded to a Silicon Photocathode for Solar Hydrogen Evolution

The production of fuels from sunlight represents one of the main challenges in the development of a sustainable energy system. Hydrogen is the simplest fuel to produce and although platinum and other noble metals are efficient catalysts for photoelectrochemical hydrogen evolution earth-abundant alternatives are needed for large-scale use. We show that bioinspired molecular clusters based on molybdenum and sulphur evolve hydrogen at rates comparable to that of platinum. The incomplete cubane-like clusters (Mo{sub 3}S{sub 4}) efficiently catalyse the evolution of hydrogen when coupled to a p-type Si semiconductor that harvests red photons in the solar spectrum. The current densities at the reversible potential match the requirement of a photoelectrochemical hydrogen production system with a solar-to-hydrogen efficiency in excess of 10% (ref. 16). The experimental observations are supported by density functional theory calculations of the Mo{sub 3}S{sub 4} clusters adsorbed on the hydrogen-terminated Si(100) surface, providing insights into the nature of the active site.
Date: November 8, 2011
Creator: Hou, Yidong
Object Type: Article
System: The UNT Digital Library
String Theory and Water Waves (open access)

String Theory and Water Waves

None
Date: July 8, 2013
Creator: Iyer, Ramakrishnan; Johnson, Clifford V. & Pennington, Jeffrey S.
Object Type: Article
System: The UNT Digital Library
Production of Energy Efficient Preform Structures (PEEPS) (open access)

Production of Energy Efficient Preform Structures (PEEPS)

Due to its low density, good structural characteristics, excellent fabrication properties, and attractive appearance, aluminum metal and its alloys continue to be widely utilized. The transportation industry continues to be the largest consumer of aluminum products, with aerospace as the principal driver for this use. Boeing has long been the largest single company consumer of heat-treated aluminum in the U.S. The extensive use of aluminum to build aircraft and launch vehicles has been sustained, despite the growing reliance on more structurally efficient carbon fiber reinforced composite materials. The trend in the aerospace industry over the past several decades has been to rely extensively on large, complex, thin-walled, monolithic machined structural components, which are fabricated from heavy billets and thick plate using high speed machining. The use of these high buy-to-fly ratio starting product forms, while currently cost effective, is energy inefficient, with a high environmental impact. The widespread implementation of Solid State Joining (SSJ) technologies, to produce lower buy-to-fly ratio starting forms, tailored to each specific application, offers the potential for a more sustainable manufacturing strategy, which would consume less energy, require less material, and reduce material and manufacturing costs. One objective of this project was to project the energy …
Date: June 8, 2012
Creator: Baumann, John A.
Object Type: Report
System: The UNT Digital Library
SUMMARY OF FY11 SULFATE RETENTION STUDIES FOR DEFENSE WASTE PROCESSING FACILITY GLASS (open access)

SUMMARY OF FY11 SULFATE RETENTION STUDIES FOR DEFENSE WASTE PROCESSING FACILITY GLASS

This report describes the results of studies related to the incorporation of sulfate in high level waste (HLW) borosilicate glass produced at the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF). A group of simulated HLW glasses produced for earlier sulfate retention studies was selected for full chemical composition measurements to determine whether there is any clear link between composition and sulfate retention over the compositional region evaluated. In addition, the viscosity of several glasses was measured to support future efforts in modeling sulfate solubility as a function of predicted viscosity. The intent of these studies was to develop a better understanding of sulfate retention in borosilicate HLW glass to allow for higher loadings of sulfate containing waste. Based on the results of these and other studies, the ability to improve sulfate solubility in DWPF borosilicate glasses lies in reducing the connectivity of the glass network structure. This can be achieved, as an example, by increasing the concentration of alkali species in the glass. However, this must be balanced with other effects of reduced network connectivity, such as reduced viscosity, potentially lower chemical durability, and in the case of higher sodium and aluminum concentrations, the propensity for nepheline crystallization. …
Date: May 8, 2012
Creator: Fox, K. & Edwards, T.
Object Type: Report
System: The UNT Digital Library
CESIUM REMOVAL FROM TANKS 241-AN-103 & 241-SX-105 & 241-AZ-101/102 COMPOSITE FOR TESTING IN BENCH SCALE STEAM REFORMER (open access)

CESIUM REMOVAL FROM TANKS 241-AN-103 & 241-SX-105 & 241-AZ-101/102 COMPOSITE FOR TESTING IN BENCH SCALE STEAM REFORMER

This report documents the preparation of three actual Hanford tank waste samples for shipment to the Savannah River National Laboratory (SRNL). Two of the samples were dissolved saltcakes from tank 241-AN-103 (hereafter AN-103) and tank 241-SX-105 (hereafter SX-105); one sample was a supernate composite from tanks 241-AZ-101 and 241-AZ-102 (hereafter AZ-101/102). The preparation of the samples was executed following the test plans LAB-PLAN-10-00006, Test Plan for the Preparation of Samples from Hanford Tanks 241-SX-105, 241-AN-103, 241-AN-107, and LAB-PLN-10-00014, Test Plan for the Preparation of a Composite Sample from Hanford Tanks 241-AZ-101 and 241-AZ-102 for Steam Reformer Testing at the Savannah River National Laboratory. All procedural steps were recorded in laboratory notebook HNF-N-274 3. Sample breakdown diagrams for AN-103 and SX-105 are presented in Appendix A. The tank samples were prepared in support of a series of treatability studies of the Fluidized Bed Steam Reforming (FBSR) process using a Bench-Scale Reformer (BSR) at SRNL. Tests with simulants have shown that the FBSR mineralized waste form is comparable to low-activity waste glass with respect to environmental durability (WSRC-STI-2008-00268, Mineralization of Radioactive Wastes by Fluidized Bed Steam Reforming (FBSR): Comparisons to Vitreous Waste Forms and Pertinent Durability Testing). However, a rigorous assessment requires …
Date: June 8, 2011
Creator: JB, DUNCAN & HJ, HUBER
Object Type: Report
System: The UNT Digital Library
Comparison of leading parallel NAS file systems on commodity hardware (open access)

Comparison of leading parallel NAS file systems on commodity hardware

High performance computing has experienced tremendous gains in system performance over the past 20 years. Unfortunately other system capabilities, such as file I/O, have not grown commensurately. In this activity, we present the results of our tests of two leading file systems (GPFS and Lustre) on the same physical hardware. This hardware is the standard commodity storage solution in use at LLNL and, while much smaller in size, is intended to enable us to learn about differences between the two systems in terms of performance, ease of use and resilience. This work represents the first hardware consistent study of the two leading file systems that the authors are aware of.
Date: November 8, 2010
Creator: Hedges, R; Fitzgerald, K; Gary, M & Stearman, D M
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT AND DEPLOYMENT OF THE MOBILE ARM RETRIEVAL SYSTEM (MARS) - 12187 (open access)

DEVELOPMENT AND DEPLOYMENT OF THE MOBILE ARM RETRIEVAL SYSTEM (MARS) - 12187

Washington River Protection Solutions (WRPS) is developing and deploying Mobile Arm Retrieval System (MARS) technologies solutions to support retrieval of radioactive and chemical waste from underground single shell storage tanks (SST) located at the Hanford Site, which is near Richland, Washington. WRPS has developed the MARS using a standardized platform that is capable of deploying multiple retrieval technologies. To date, WRPS, working with their mentor-protege company, Columbia Energy and Environmental Services (CEES), has developed two retrieval mechanisms, MARS-Sluicing (MARS-S) and MARS-Vacuum (MARS-V). MARS-S uses pressurized fluids routed through spray nozzles to mobilize waste materials to a centrally located slurry pump (deployed in 2011). MARS-V uses pressurized fluids routed through an eductor nozzle. The eductor nozzle allows a vacuum to be drawn on the waste materials. The vacuum allows the waste materials to be moved to an in-tank vessel, then extracted from the SST and subsequently pumped to newer and safer double shell tanks (DST) for storage until the waste is treated for disposal. The MARS-S system is targeted for sound SSTs (i.e., non leaking tanks). The MARS-V is targeted for assumed leaking tanks or those tanks that are of questionable integrity. Both versions of MARS are beinglhave been developed in …
Date: November 8, 2011
Creator: CA, BURKE; MR, LANDON & CE, HANSON
Object Type: Article
System: The UNT Digital Library
Final Report for "Compact Crab Cavity Design" (open access)

Final Report for "Compact Crab Cavity Design"

The goal of this project is to provide an innovative, new crab cavity design relevant to the MEIC. Through this work, we will provide comprehensive modeling of this new cavity design, including electromagnetic, thermal, and microphonic effects. One most likely candidate configuration is the design put forward by JLab and Lancaster University, UK, researchers known as the four-rod configuration. In the Phase I, Tech-X Corporation researchers performed analysis and design optimization and iteration, utilizing their state-of-the art time-domain particle-in-cell software, on a 400 MHz design for the LHC by JLab and Lancaster University, UK, researchers known as the four-rod design.
Date: November 8, 2012
Creator: Smithe, David N
Object Type: Report
System: The UNT Digital Library
Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems (open access)

Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems

Daylight responsive dimming systems have been used in few buildings to date because they require improvements to improve reliability. The key underlying factor contributing to poor performance is the variability of the ratio of the photosensor signal to daylight workplane illuminance in accordance with sun position, sky condition, and fenestration condition. Therefore, this paper describes the integrated systems between automated roller shade systems and daylight responsive dimming systems with an improved closed-loop proportional control algorithm, and the relative performance of the integrated systems and single systems. The concept of the improved closed-loop proportional control algorithm for the integrated systems is to predict the varying correlation of photosensor signal to daylight workplane illuminance according to roller shade height and sky conditions for improvement of the system accuracy. In this study, the performance of the integrated systems with two improved closed-loop proportional control algorithms was compared with that of the current (modified) closed-loop proportional control algorithm. In the results, the average maintenance percentage and the average discrepancies of the target illuminance, as well as the average time under 90percent of target illuminance for the integrated systems significantly improved in comparison with the current closed-loop proportional control algorithm for daylight responsive dimming systems …
Date: July 8, 2010
Creator: Park, Byoung-Chul; Choi, An-Seop; Jeong, Jae-Weon & Lee, Eleanor S.
Object Type: Article
System: The UNT Digital Library
Search for Low-Mass Higgs States at BaBar (open access)

Search for Low-Mass Higgs States at BaBar

None
Date: March 8, 2013
Creator: Santoro, Valentina & /INFN, Ferrara
Object Type: Article
System: The UNT Digital Library
Optimizing New Dark Energy Experiments - Final Scientific Report (open access)

Optimizing New Dark Energy Experiments - Final Scientific Report

This is the final scientific report for the University of Pittsburgh portion of the collaborative grant, 'Optimizing New Dark Energy Experiments'
Date: June 8, 2012
Creator: Newman, Jeffrey A.
Object Type: Report
System: The UNT Digital Library
Balloon-Borne Sounding System (SONDE) Handbook (open access)

Balloon-Borne Sounding System (SONDE) Handbook

The balloon-borne sounding system (SONDE) provides in situ measurements (vertical profiles) of both the thermodynamic state of the atmosphere and the wind speed and direction.
Date: February 8, 2011
Creator: Holdridge, D; Ritsche, M; Prell, J & Coulter, R
Object Type: Report
System: The UNT Digital Library
Final Project Report for project titled "Fluoroalkylphosphonic-acid-based proton conductors" (open access)

Final Project Report for project titled "Fluoroalkylphosphonic-acid-based proton conductors"

The overall objective of this research was to create new proton-conducting polymer electrolytes for use in energy conversion devices including hydrogen fuel cells that could operate at high temperatures (95-130 C) and under low relative humidity (< 50% RH) conditions. The new polymers were based on the fluoroalkylphosphonic and phosphinic acid (FPA) groups (see illustration below) which offer prospects for rapid proton transport by a proton-hopping mechanism similar to that which operates in phosphoric acid, a well-known proton-transporting electrolyte that is used in a class of hydrogen fuel cells that work well under the conditions noted above and are already commercially successful. The two specific project objectives were as follows: (1) synthesize and characterize new proton-conducting electrolytes based on the fluoroalkylphosphonic and phosphinic acid (FPA) functional groups; and (2) create and apply new computer models to study protonic conduction in FPA-based electrolytes. The project was successful in creating the desired polymer electrolytes and also a series of molecular model compounds which were used to study proton transport in FPA electrolytes in general. Computer models were created to study both structure and proton-transport dynamics in the electrolytes, particularly the molecular model compounds. Rapid proton transport by a hopping mechanism was found …
Date: December 8, 2011
Creator: Creager, Stephen
Object Type: Report
System: The UNT Digital Library
The Importance of High Temporal Resolution in Modeling Renewable Energy Penetration Scenarios (open access)

The Importance of High Temporal Resolution in Modeling Renewable Energy Penetration Scenarios

Traditionally, modeling investment and dispatch problems in electricity economics has been limited by computation power. Due to this limitation, simplifications are applied. One common practice, for example, is to reduce the temporal resolution of the dispatch by clustering similar load levels. The increase of intermittent electricity from renewable energy sources (RES-E) changes the validity of this assumption. RES-E already cover a certain amount of the total demand. This leaves an increasingly volatile residual demand to be matched by the conventional power market. This paper quantifies differences in investment decisions by applying three different time-resolution residual load patterns in an investment and dispatch power system model. The model optimizes investment decisions in five year steps between today and 2030 with residual load levels for 8760, 288 and 16 time slices per year. The market under consideration is the four zone ERCOT market in Texas. The results show that investment decisions significantly differ across the three scenarios. In particular, investments into base-load technologies are substantially reduced in the high resolution scenario (8760 residual load levels) relative to the scenarios with lower temporal resolution. Additionally, the amount of RES-E curtailment and the market value of RES-E exhibit noteworthy differences.
Date: October 8, 2010
Creator: Nicolosi, Marco; Mills, Andrew D & Wiser, Ryan H
Object Type: Article
System: The UNT Digital Library
Livermore Lab's giant laser system will bring star power to Earth (open access)

Livermore Lab's giant laser system will bring star power to Earth

In the 50 years since the laser was first demonstrated in Malibu, California, on May 16, 1960, Lawrence Livermore National Laboratory (LLNL) has been a world leader in laser technology and the home for many of the world's most advanced laser systems. That tradition continues today at LLNL's National Ignition Facility (NIF), the world's most energetic laser system. NIF's completion in March 2009 not only marked the dawn of a new era of scientific research - it could also prove to be the next big step in the quest for a sustainable, carbon-free energy source for the world. NIF consists of 192 laser beams that will focus up to 1.8 million joules of energy on a bb-sized target filled with isotopes of hydrogen - forcing the hydrogen nuclei to collide and fuse in a controlled thermonuclear reaction similar to what happens in the sun and the stars. More energy will be produced by this 'ignition' reaction than the amount of laser energy required to start it. This is the long-sought goal of 'energy gain' that has eluded fusion researchers for more than half a century. Success will be a scientific breakthrough - the first demonstration of fusion ignition in a …
Date: April 8, 2010
Creator: Moses, Edward
Object Type: Article
System: The UNT Digital Library
Astatine-211 Radiochemistry: The Development of Methodologies for High Activity Level Radiosynthesis (open access)

Astatine-211 Radiochemistry: The Development of Methodologies for High Activity Level Radiosynthesis

Targeted radionuclide therapy is emerging as a viable approach for cancer treatment because of its potential for delivering curative doses of radiation to malignant cell populations while sparing normal tissues. Alpha particles such as those emitted by 211At are particularly attractive for this purpose because of their short path length in tissue and high energy, making them highly effective in killing cancer cells. The current impact of targeted radiotherapy in the clinical domain remains limited despite the fact that in many cases, potentially useful molecular targets and labeled compounds have already been identified. Unfortunately, putting these concepts into practice has been impeded by limitations in radiochemistry methodologies. A critical problem is that the synthesis of therapeutic radiopharmaceuticals provides additional challenges in comparison to diagnostic reagents because of the need to perform radio-synthesis at high levels of radioactivity. This is particularly important for {alpha}-particle emitters such as 211At because they deposit large amounts of energy in a highly focal manner. The overall objective of this project is to develop convenient and reproducible radiochemical methodologies for the radiohalogenation of molecules with the {alpha}-particle emitter 211At at the radioactivity levels needed for clinical studies. Our goal is to address two problems in astatine …
Date: August 8, 2012
Creator: Zalutsky, Michael R.
Object Type: Report
System: The UNT Digital Library
Notes from the Unit Commitment Linear Programming Project (open access)

Notes from the Unit Commitment Linear Programming Project

None
Date: August 8, 2012
Creator: Rountree, B. L.
Object Type: Report
System: The UNT Digital Library
Addendum to High Pressure Burn Rate Measurements on an Ammonium Perchlorate Propellant (open access)

Addendum to High Pressure Burn Rate Measurements on an Ammonium Perchlorate Propellant

As part of a small follow-on study, the burn rate of the ammonium perchlorate (AP) based material TAL-1503 was studied at a relatively mild pressure. The goal of this final experiment was to burn TAL-1503 at the lowest pressures possible using the LLNL High Pressure Strand Burner (LLNL-HPSB). The following is a description of the experiment and the results with a brief discussion of data and a comparison to the higher pressure data. This is not meant to be a stand-alone report and readers should refer to the main report for experimental details and discussion. High pressure deflagration rate measurements of a unique AP/HTPB based material (TAL-1503) were performed using the LLNL high pressure strand burner apparatus. The material burns in a well behaved, laminar fashion between 20 and 300 MPa with a burn law of B = (0.6 {+-} 0.1) x P{sup (1.05{+-}0.02)} that was calculated based on the best data available from the experiments. In the pressure range of 2 and 10 MPa the material burned laminarly with a burn law of B = (2.0 {+-} 0.2) x P{sup (0.66{+-}0.05)}. In these results, B is the burn rate in mm/s and P is the pressure in units of …
Date: November 8, 2010
Creator: Glascoe, E A & Tan, N
Object Type: Report
System: The UNT Digital Library