DARHT-II Injector Transients and the Ferrite Damper (open access)

DARHT-II Injector Transients and the Ferrite Damper

This report summarizes the transient response of the DARHT-II Injector and the design of the ferrite damper. Initial commissioning of the injector revealed a rise time excited 7.8 MHz oscillation on the diode voltage and stalk current leading to a 7.8 MHz modulation of the beam current, position, and energy. Commissioning also revealed that the use of the crowbar to decrease the voltage fall time excited a spectrum of radio frequency modes which caused concern that there might be significant transient RF electric field stresses imposed on the high voltage column insulators. Based on the experience of damping the induction cell RF modes with ferrite, the concept of a ferrite damper was developed to address the crowbar-excited oscillations as well as the rise-time-excited 7.8 MHz oscillations. After the Project decided to discontinue the use of the crowbar, further development of the concept focused exclusively on damping the oscillations excited by the rise time. The design was completed and the ferrite damper was installed in the DARHT-II Injector in February 2006. The organization of this report is as follows. The suite of injector diagnostics are described in Section 2. The data and modeling of the injector transients excited on the rise-time …
Date: August 4, 2006
Creator: Waldron, Will; Reginato, Lou; Chow, Ken; Houck, Tim; Henestroza, Enrique; Yu, Simon et al.
Object Type: Report
System: The UNT Digital Library
Structure of incommensurate gold sulfide monolayer on Au(111) (open access)

Structure of incommensurate gold sulfide monolayer on Au(111)

Two-dimensional confined systems, such as substrate-supported incommensurate layers, are of interest because their structural and electronic properties may differ from those of bulk materials. While advances in experimental techniques have resulted in the growth of many such interesting systems, progress can often be hampered by the lack of an atomistic-scale understanding of the structure, especially for incommensurate systems. In this work, we develop an atomic-scale model for an ordered incommensurate gold-sulfide (AuS) adlayer that has been previously demonstrated to exist on the Au(111) surface, following sulfur deposition and annealing to 450 K. We introduce theoretical techniques within density functional theory to take into account charge transfer in an incommensurate system and model scanning tunneling microscopy images, which are in good agreement with experiment. Our simulations indicate that this model is remarkably robust. We analyze the nature of bonding in this structure using state-of-the-art Wannier-function based techniques. Our analysis provides a natural explanation for the extraordinary robustness and unusual stoichiometry of this layer. This structure and its chemistry have implications for related S-Au interfaces, such as those in self-assembled monolayers of thiols on Au substrates.
Date: October 4, 2006
Creator: Quek, S Y; Biener, M M; Biener, J; Bhattacharjee, J; Friend, C M; Waghmare, U V et al.
Object Type: Article
System: The UNT Digital Library
A sampling-based Bayesian model for gas saturation estimationusing seismic AVA and marine CSEM data (open access)

A sampling-based Bayesian model for gas saturation estimationusing seismic AVA and marine CSEM data

We develop a sampling-based Bayesian model to jointly invertseismic amplitude versus angles (AVA) and marine controlled-sourceelectromagnetic (CSEM) data for layered reservoir models. The porosityand fluid saturation in each layer of the reservoir, the seismic P- andS-wave velocity and density in the layers below and above the reservoir,and the electrical conductivity of the overburden are considered asrandom variables. Pre-stack seismic AVA data in a selected time windowand real and quadrature components of the recorded electrical field areconsidered as data. We use Markov chain Monte Carlo (MCMC) samplingmethods to obtain a large number of samples from the joint posteriordistribution function. Using those samples, we obtain not only estimatesof each unknown variable, but also its uncertainty information. Thedeveloped method is applied to both synthetic and field data to explorethe combined use of seismic AVA and EM data for gas saturationestimation. Results show that the developed method is effective for jointinversion, and the incorporation of CSEM data reduces uncertainty influid saturation estimation, when compared to results from inversion ofAVA data only.
Date: April 4, 2006
Creator: Chen, Jinsong; Hoversten, Michael; Vasco, Don; Rubin, Yoram & Hou,Zhangshuan
Object Type: Article
System: The UNT Digital Library
FreedomCAR Advanced Traction Drive Motor Development Phase I (open access)

FreedomCAR Advanced Traction Drive Motor Development Phase I

None
Date: August 4, 2006
Creator: Ley, J. & Lutz, J.
Object Type: Report
System: The UNT Digital Library
Innovative Electromagnetic Sensors for Pipeline Crawlers Progress Report: October 2005 - March 2006 (open access)

Innovative Electromagnetic Sensors for Pipeline Crawlers Progress Report: October 2005 - March 2006

Internal inspection of pipelines is an important tool for ensuring safe and reliable delivery of fossil energy products. Current inspection systems that are propelled through the pipeline by the product flow cannot be used to inspect all pipelines because of the various physical barriers they encounter. Recent development efforts include a new generation of powered inspection platforms that crawl slowly inside a pipeline and are able to maneuver past the physical barriers that can limit inspection. At Battelle, innovative electromagnetic sensors are being designed and tested for these new pipeline crawlers. The various sensor types can be used to assess a wide range of pipeline anomalies including corrosion, mechanical damage, and cracks. Battelle is in the final year on a projected three-year development effort. In the first year, two innovative electromagnetic inspection technologies were designed and tested. Both were based on moving high-strength permanent magnets to generate inspection energy. One system involved translating permanent magnets towards the pipe. A pulse of electric current would be induced in the pipe to oppose the magnetization according to Lenz's Law. The decay of this pulse would indicate the presence of defects in the pipe wall. This inspection method is similar to pulsed eddy …
Date: May 4, 2006
Creator: Nestleroth, J. Bruce
Object Type: Report
System: The UNT Digital Library
Configuration Studies and Recommendations for the ILC Damping Rings (open access)

Configuration Studies and Recommendations for the ILC Damping Rings

We describe the results of studies comparing differentoptions for the baseline configuration of the ILC damping rings. Theprincipal configuration decisions apply to the circumference, beamenergy, lattice type, and technology options for key components,including the injection/extraction kickers and the damping wigglers. Toarrive at our recommended configuration, we performed detailed studies ofa range of lattices representing a variety of different configurationoptions; these lattices are described in Chapter 2. The results of thevarious studies are reported in chapters covering issues of beamdynamics, technical subsystems, costs, and commissioning, reliability andupgradeability. Our detailed recommendations for the baselineconfiguration are given in Chapter 7, where we also outline furtherresearch and development that is needed before a machine using ourrecommended configuration can be built and operated successfully. In thesame chapter, we suggest possible alternatives to the baselineconfiguration.
Date: February 4, 2006
Creator: Wolski, Andrzej; Gao, Jie & Guiducci, Susanna
Object Type: Report
System: The UNT Digital Library
TWO-PHASE FLOW STUDIES IN NUCLEAR POWER PLANT PRIMARY CIRCUITS USING THE THREE-DIMENSIONAL THERMAL-HYDRAULIC CODE BAGIRA. (open access)

TWO-PHASE FLOW STUDIES IN NUCLEAR POWER PLANT PRIMARY CIRCUITS USING THE THREE-DIMENSIONAL THERMAL-HYDRAULIC CODE BAGIRA.

In this paper we present recent results of the application of the thermal-hydraulic code BAGIRA to the analysis of complex two-phase flows in nuclear power plants primary loops. In particular, we performed benchmark numerical simulation of an integral LOCA experiment performed on a test facility modeling the primary circuit of VVER-1000. In addition, we have also analyzed the flow patterns in the VVER-1000 steam generator vessel for stationary and transient operation regimes. For both of these experiments we have compared the numerical results with measured data. Finally, we demonstrate the capabilities of BAGIRA by modeling a hypothetical severe accident for a VVER-1000 type nuclear reactor. The numerical analysis, which modeled all stages of the hypothetical severe accident up to the complete ablation of the reactor cavity bottom, shows the importance of multi-dimensional flow effects.
Date: June 4, 2006
Creator: KOHURT, P. (BNL), KALINICHENKO, S.D.; KROSHILIN, A.E.; KROSHILIN, V.E. & SMIRNOV, A.V.
Object Type: Article
System: The UNT Digital Library
LSST Detector Module and Raft Assembly Metrology Concepts (open access)

LSST Detector Module and Raft Assembly Metrology Concepts

None
Date: May 4, 2006
Creator: Takacs, P. Z.; O'Connor, P.; Radeka, V.; Mahler, G.; Frank. J. & Geary, J.
Object Type: Article
System: The UNT Digital Library
Booming Plutons: Source of microearthquakes in South Carolina (open access)

Booming Plutons: Source of microearthquakes in South Carolina

None
Date: January 4, 2006
Creator: Stevenson, Donald
Object Type: Article
System: The UNT Digital Library
Alternator Electrical Feedthrough Insulator Materials for Project Prometheus (open access)

Alternator Electrical Feedthrough Insulator Materials for Project Prometheus

None
Date: January 4, 2006
Creator: Clobes, Jason K. & Ruminski, Andrew M.
Object Type: Report
System: The UNT Digital Library
Large-Scale First-Principles Molecular Dynamics Simulations on the BlueGene/L Platform using the Qbox Code (open access)

Large-Scale First-Principles Molecular Dynamics Simulations on the BlueGene/L Platform using the Qbox Code

First-Principles Molecular Dynamics (FPMD) is an accurate, atomistic simulation approach that is routinely applied to a variety of areas including solid-state physics, chemistry, biochemistry and nanotechnology. FPMD enables one to perform predictive materials simulations, as no empirical or adjustable parameters are used to describe a given system. Instead, a quantum mechanical description of electrons is obtained by solving the Kohn-Sham equations within a pseudopotential plane-wave formalism. This rigorous first-principles treatment of electronic structure is computationally expensive and limits the size of tractable systems to a few hundred atoms on most currently available parallel computers. Developed specifically for large parallel systems at LLNL's Center for Applied Scientific Computing, the Qbox implementation of the FPMD method shows unprecedented performance and scaling on BlueGene/L.
Date: January 4, 2006
Creator: Gygi, F.; Draeger, E.; de Supinski, B.; Yates, R. K.; Franchetti, F.; Kral, S. et al.
Object Type: Report
System: The UNT Digital Library
A Universe Without Weak Interactions (open access)

A Universe Without Weak Interactions

None
Date: April 4, 2006
Creator: Harnik, Roni; Kribs, Graham D. & Perez, Gilad
Object Type: Article
System: The UNT Digital Library
Remaining Sites Verification Package for the 126-F-2, 183-F Clearwells, Waste Site Reclassification Form 2006-017 (open access)

Remaining Sites Verification Package for the 126-F-2, 183-F Clearwells, Waste Site Reclassification Form 2006-017

The 126-F-2 site is the clearwell facility formerly used as part of the reactor cooling water treatment at the 183-F facility. During demolition operations in the 1970s, potentially contaminated debris was disposed in the eastern clearwell structure. The site has been remediated by removing all debris in the clearwell structure to the Environmental Restoration Disposal Facility. The results of radiological surveys and visual inspection of the remediated clearwell structure show neither residual contamination nor the potential for contaminant migration beyond the clearwell boundaries. The results of verification sampling at the remediation waste staging area demonstrated that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also showed that residual contaminant concentrations are protective of groundwater and the Columbia River.
Date: May 4, 2006
Creator: Carlson, R. A.
Object Type: Report
System: The UNT Digital Library
Coordination of 1,4-Diazabutadiene Ligands to Decamethylytterbocene: Additional Examples of Spin Coupling in Ytterbocene Complexes (open access)

Coordination of 1,4-Diazabutadiene Ligands to Decamethylytterbocene: Additional Examples of Spin Coupling in Ytterbocene Complexes

The paramagnetic 1:1 coordination complexes of (C5Me5)2Yb with a series of diazabutadiene ligands, RN=C(R')C(R')=NR, where R= CMe3, CHMe2, adamantyl, p-tolyl, p-anisyl, and mesityl when R'=H, and R= p-anisyl when R'= Me, have been prepared. The complexes are paramagnetic, but their magnetic moments are less than expected for the two uncoupled spin carriers, (C5Me5)2Yb(III, 4f13) and the diazabutadiene radical anions (S=1/2), which implies exchange coupling between the spins. The variable temperature 1H NMR spectra show that rotation about the R-N bond is hindered and these barriers are estimated. The barriers are largely determined by steric effects but electronic effects are not unimportant.
Date: November 4, 2006
Creator: Andersen, Richard; Walter, Marc D.; Berg, David J. & Andersen, Richard A.
Object Type: Article
System: The UNT Digital Library
Cleanup Verification Package for the 116-K-2 Effluent Trench (open access)

Cleanup Verification Package for the 116-K-2 Effluent Trench

This cleanup verification package documents completion of remedial action for the 116-K-2 effluent trench, also referred to as the 116-K-2 mile-long trench and the 116-K-2 site. During its period of operation, the 116-K-2 site was used to dispose of cooling water effluent from the 105-KE and 105-KW Reactors by percolation into the soil. This site also received mixed liquid wastes from the 105-KW and 105-KE fuel storage basins, reactor floor drains, and miscellaneous decontamination activities.
Date: April 4, 2006
Creator: Capron, J. M.
Object Type: Report
System: The UNT Digital Library
Annual Report for Gravity Collection Lysimeter Monitoring Plan – ERDF Cells 5 and 6 (open access)

Annual Report for Gravity Collection Lysimeter Monitoring Plan – ERDF Cells 5 and 6

The data and analyses contained in this report reflect the initial characterization of construction and consolidation water in Cells 5 and 6 lysimeters. Therefore, the scope of this report will be to establish constituent levels and document dewatering activities completed to date.
Date: April 4, 2006
Creator: Proctor, M. L.
Object Type: Report
System: The UNT Digital Library
Scaling laws for collisionless laser-plasma interactions of relevance for laboratory astrophysics (open access)

Scaling laws for collisionless laser-plasma interactions of relevance for laboratory astrophysics

Scaling laws for interaction of ultra-intense laser beams with a collisionless plasmas are discussed. Special attention is paid to the problem of the collective ion acceleration. Symmetry arguments in application to the generation of the poloidal magnetic field are presented. A heuristic model for evaluating the magnetic field strength is proposed.
Date: April 4, 2006
Creator: Ryutov, D. D. & Rermington, B. A.
Object Type: Article
System: The UNT Digital Library
A Cartesian embedded boundary method for hyperbolic conservation laws (open access)

A Cartesian embedded boundary method for hyperbolic conservation laws

The authors develop an embedded boundary finite difference technique for solving the compressible two- or three-dimensional Euler equations in complex geometries on a Cartesian grid. The method is second order accurate with an explicit time step determined by the grid size away from the boundary. Slope limiters are used on the embedded boundary to avoid non-physical oscillations near shock waves. They show computed examples of supersonic flow past a cylinder and compare with results computed on a body fitted grid. Furthermore, they discuss the implementation of the method for thin geometries, and show computed examples of transonic flow past an airfoil.
Date: December 4, 2006
Creator: Sjogreen, B & Petersson, N A
Object Type: Article
System: The UNT Digital Library
Groundwater and Leachate Monitoring and Sampling at the Environmental Restoration Disposal Facility, Calendar Year 2005 (open access)

Groundwater and Leachate Monitoring and Sampling at the Environmental Restoration Disposal Facility, Calendar Year 2005

The purpose of this annual monitoring report is to evaluate the conditions of and identify trends for groundwater beneath the ERDF and to report leachate results in accordance with the requirements specified in the ERDF ROD.
Date: May 4, 2006
Creator: D.A. St. John, R.L. Weiss
Object Type: Report
System: The UNT Digital Library
Thomson scattering techniques in laser produced plasmas (open access)

Thomson scattering techniques in laser produced plasmas

Thomson scattering has been shown to be a valuable technique for measuring the plasma conditions in laser produced plasmas. Measurement techniques are discussed that use the ion-acoustic frequency measured from the collective Thomson-scattering spectrum to extract the electron temperature, ion temperature, plasma flow, and electron density in a laser produced plasma. In a recent study, they demonstrated a novel Thomson-scattering technique to measure the dispersion of ion-acoustic fluctuations that employing multiple color Thomson-scattering diagnostics. They obtained frequency-resolved Thomson-scattering spectra of the two separate thermal ion-acoustic fluctuations with significantly different wave vectors. This new technique allows a simultaneous time resolved local measurement of electron density and temperature. The plasma fluctuations are shown to become dispersive with increasing electron temperature. Furthermore, a Thomson-scattering technique to measure the electron temperature profile is presented where recent experiments have measured a large electron temperature gradient (Te = 1.4 keV to Te = 3.2 keV over 1.5-mm) along the axis of a 2-mm long hohlraum when heated asymmetrically.
Date: May 4, 2006
Creator: Froula, D. H.; Ross, J. S.; Divol, L.; MacKinnon, A. J.; Sorce, C. & Glenzer, S. H.
Object Type: Article
System: The UNT Digital Library
The Influence of Composition upon Surface Degradation and Stress Corrosion Cracking of the Ni-Cr-Mo Alloys in Wet Hydrofluoric Acid (open access)

The Influence of Composition upon Surface Degradation and Stress Corrosion Cracking of the Ni-Cr-Mo Alloys in Wet Hydrofluoric Acid

At concentrations below 60%, wet hydrofluoric acid (HF) is extremely corrosive to steels, stainless steels and reactive metals, such as titanium, zirconium, and tantalum. In fact, only a few metallic materials will withstand wet HF at temperatures above ambient. Among these are the nickel-copper (Ni-Cu) and nickel-chromium-molybdenum (Ni-Cr-Mo) alloys. Previous work has shown that, even with these materials, there are complicating factors. For example, under certain conditions, internal attack and stress corrosion cracking (SCC) are possible with the Ni-Cr-Mo alloys, and the Ni-Cu materials can suffer intergranular attack when exposed to wet HF vapors. The purpose of this work was to study further the response of the Ni-Cr-Mo alloys to HF, in particular their external corrosion rates, susceptibility to internal attack and susceptibility to HF-induced SCC, as a function of alloy composition. As a side experiment, one of the alloys was tested in two microstructural conditions, i.e. solution annealed (the usual condition for materials of this type) and long-range ordered (this being a means of strengthening the alloy in question). The study of external corrosion rates over wide ranges of concentration and temperature revealed a strong beneficial influence of molybdenum content. However, tungsten, which is used as a partial replacement …
Date: December 4, 2006
Creator: Crook, P; Meck, N S & Rebak, R B
Object Type: Article
System: The UNT Digital Library
ARAMS/FRAMES JOINT FREQUENCY DATA (JFD) GENERATOR (open access)

ARAMS/FRAMES JOINT FREQUENCY DATA (JFD) GENERATOR

An ARAMS/FRAMES utility entitled ''Joint Frequency Data (JFD) Generator'' provides the capability of creating joint frequency tables. The resultant JFD tables contain summaries of the frequency of occurrence of meteorological dispersion, wind speed, and wind direction that are required as input in climatological air dispersion models. The JFD Generator computations are made by an updated version of the EPA STAR (STAbility ARray) program. Surface observations are combined with computed seasonally and diurnally varying solar flux rates to estimate the ambient atmospheric dispersion rates, represented as a stability category. The wind speeds and directions are obtained directly from the hourly surface observation data. The product is a file in a format that can be directly read by an air dispersion model. The JFD Generator can input hourly meteorological surface observation data in CD-144, Samson, and SCRAM data formats. An enhanced joint frequency table file that can be read directly by the ARAMS/FRAMES interface is produced. The output file has a format can be used by the MEPAS air dispersion program or can be modified for input to other models requiring joint frequency input.
Date: October 4, 2006
Creator: Droppo, James G. & Pelton, Mitch A.
Object Type: Report
System: The UNT Digital Library
Advanced Modular Inverter Technology Development (open access)

Advanced Modular Inverter Technology Development

Electric and hybrid-electric vehicle systems require an inverter to convert the direct current (DC) output of the energy generation/storage system (engine, fuel cells, or batteries) to the alternating current (AC) that vehicle propulsion motors use. Vehicle support systems, such as lights and air conditioning, also use the inverter AC output. Distributed energy systems require an inverter to provide the high quality AC output that energy system customers demand. Today's inverters are expensive due to the cost of the power electronics components, and system designers must also tailor the inverter for individual applications. Thus, the benefits of mass production are not available, resulting in high initial procurement costs as well as high inverter maintenance and repair costs. Electricore, Inc. (www.electricore.org) a public good 501 (c) (3) not-for-profit advanced technology development consortium assembled a highly qualified team consisting of AeroVironment Inc. (www.aerovironment.com) and Delphi Automotive Systems LLC (Delphi), (www.delphi.com), as equal tiered technical leads, to develop an advanced, modular construction, inverter packaging technology that will offer a 30% cost reduction over conventional designs adding to the development of energy conversion technologies for crosscutting applications in the building, industry, transportation, and utility sectors. The proposed inverter allows for a reduction of weight and …
Date: February 4, 2006
Creator: Szczepanek, Adam
Object Type: Report
System: The UNT Digital Library
Assessing Terrorist Motivations for Attacking Critical Infrastructure (open access)

Assessing Terrorist Motivations for Attacking Critical Infrastructure

Certain types of infrastructure--critical infrastructure (CI)--play vital roles in underpinning our economy, security and way of life. These complex and often interconnected systems have become so ubiquitous and essential to day-to-day life that they are easily taken for granted. Often it is only when the important services provided by such infrastructure are interrupted--when we lose easy access to electricity, health care, telecommunications, transportation or water, for example--that we are conscious of our great dependence on these networks and of the vulnerabilities that stem from such dependence. Unfortunately, it must be assumed that many terrorists are all too aware that CI facilities pose high-value targets that, if successfully attacked, have the potential to dramatically disrupt the normal rhythm of society, cause public fear and intimidation, and generate significant publicity. Indeed, revelations emerging at the time of this writing about Al Qaida's efforts to prepare for possible attacks on major financial facilities in New York, New Jersey, and the District of Columbia remind us just how real and immediate such threats to CI may be. Simply being aware that our nation's critical infrastructure presents terrorists with a plethora of targets, however, does little to mitigate the dangers of CI attacks. In order …
Date: December 4, 2006
Creator: Ackerman, G.; Abhayaratne, P.; Bale, J.; Bhattacharjee, A.; Blair, C.; Hansell, L. et al.
Object Type: Report
System: The UNT Digital Library