Analysis of Deformation Twinning in Tantalum Single Crystals Under Shock Loading Conditions (open access)

Analysis of Deformation Twinning in Tantalum Single Crystals Under Shock Loading Conditions

None
Date: December 5, 2012
Creator: Florando, J. N.; Barton, N. R.; El-Dasher, B.; McNaney, J. M. & Kumar, M.
Object Type: Article
System: The UNT Digital Library
Long-Term Colloid Mobilization And Colloid-Facilitated Transport Of Radionuclides In A Semi-Arid Vadose Zone (open access)

Long-Term Colloid Mobilization And Colloid-Facilitated Transport Of Radionuclides In A Semi-Arid Vadose Zone

The main purpose of this project was to improve the fundamental mechanistic understanding and quantification of long-term colloid mobilization and colloid-facilitated transport of radionuclides in the vadose zone, with special emphasis on the semi-arid Hanford site. While we focused some of the experiments on hydrogeological and geochemical conditions of the Hanford site, many of our results apply to colloid and colloid-facilitated transport in general. Specific objectives were (1) to determine the mechanisms of colloid mobilization and colloid-facilitated radionuclide transport in undisturbed Hanford sediments under unsaturated flow, (2) to quantify in situ colloid mobilization and colloid-facilitated radionuclide transport from Hanford sediments under field conditions, and (3) to develop a field-scale conceptual and numerical model for colloid mobilization and transport at the Hanford vadose zone, and use that model to predict long-term colloid and colloid- facilitated radionuclide transport. To achieve these goals and objectives, we have used a combination of experimental, theoretical, and numerical methods at different spatial scales, ranging from microscopic investigations of single particle attachment and detachment to larger-scale field experiments using outdoor lysimeters at the Hanford site. Microscopic and single particle investigations provided fundamental insight into mechanisms of colloid interactions with the air-water interface. We could show that a …
Date: November 5, 2012
Creator: Flury, Markus; Harsh, James B; Zhang, Fred; Gee, Glendon W; Mattson, Earl D & Lichtner, Peter C
Object Type: Text
System: The UNT Digital Library
ENERGY PARTITIONING, ENERGY COUPLING (EPEC) EXPERIMENTS AT THE NATIONAL IGNITION FACILITY (open access)

ENERGY PARTITIONING, ENERGY COUPLING (EPEC) EXPERIMENTS AT THE NATIONAL IGNITION FACILITY

The energy-partitioning, energy-coupling (EPEC) experiments at the National Ignition Facility (NIF) will simultaneously measure the coupling of energy into both ground shock and air-blast overpressure from a laser-driven target. The source target for the experiment is positioned at a known height above the ground-surface simulant and is heated by four beams from NIF. The resulting target energy density and specific energy are equal to those of a low-yield nuclear device. The ground-shock stress waves and atmospheric overpressure waveforms that result in our test system are hydrodynamically scaled analogs of seismic and air-blast phenomena caused by a nuclear weapon. In what follows, we discuss the motivation for our investigation and briefly describe NIF. Then, we introduce the EPEC experiments, including diagnostics, in more detail.
Date: January 5, 2012
Creator: Fournier, K B; Brown, C G; May, M J; Dunlop, W H; Compton, S M; Kane, J O et al.
Object Type: Report
System: The UNT Digital Library
A Multigrid-in-Time Algorithm for Solving Evolution Equations in Parallel (open access)

A Multigrid-in-Time Algorithm for Solving Evolution Equations in Parallel

None
Date: December 5, 2012
Creator: Friedhoff, S; Falgout, R D; Kolev, T V; MacLachlan, S & Schroder, J B
Object Type: Article
System: The UNT Digital Library
Post-growth annealing to improve the performance of CdZnTe detectors (open access)

Post-growth annealing to improve the performance of CdZnTe detectors

N/A
Date: June 5, 2012
Creator: G., Yang
Object Type: Article
System: The UNT Digital Library
Muon Muon Collider: Feasibility Study (open access)

Muon Muon Collider: Feasibility Study

A feasibility study is presented of a 2 + 2 TeV muon collider with a luminosity of L = 10{sup 35} cm{sup -2}s{sup -1}. The resulting design is not optimized for performance, and certainly not for cost; however, it does suffice - we believe - to allow us to make a credible case, that a muon collider is a serious possibility for particle physics and, therefore, worthy of R and D support so that the reality of, and interest in, a muon collider can be better assayed. The goal of this support would be to completely assess the physics potential and to evaluate the cost and development of the necessary technology. The muon collider complex consists of components which first produce copious pions, then capture the pions and the resulting muons from their decay; this is followed by an ionization cooling channel to reduce the longitudinal and transverse emittance of the muon beam. The next stage is to accelerate the muons and, finally, inject them into a collider ring wich has a small beta function at the colliding point. This is the first attempt at a point design and it will require further study and optimization. Experimental work will be …
Date: April 5, 2012
Creator: Gallardo, J. C.; Palmer, R. B.; Tollestrup, A. V.; Sessler, A. M.; Skrinsky, A. N.; Geer, S. et al.
Object Type: Article
System: The UNT Digital Library
Ability to Repay, Risk-Retention Standards, and Mortgage Credit Access (open access)

Ability to Repay, Risk-Retention Standards, and Mortgage Credit Access

This report examines the developments associated with the implementation of mortgage lending reforms. The report begins with a summary of proposed ability to repay and risk-retention standards. Next, the report describes risky underwriting and financing practices that occurred prior to the mortgage crisis, followed by a discussion of how access to mortgage credit might be affected.
Date: June 5, 2012
Creator: Getter, Darryl E.
Object Type: Report
System: The UNT Digital Library
Dynamic structure factor in warm dense beryllium (open access)

Dynamic structure factor in warm dense beryllium

None
Date: April 5, 2012
Creator: Glenzer, S H; Fortmann, C; Doeppner, T; Plagemann, K U; Sperling, P; Thiele, R et al.
Object Type: Article
System: The UNT Digital Library
Lithospheric Models of the Middle East to Improve Seismic Source Parameter Determination/Event Location Accuracy (open access)

Lithospheric Models of the Middle East to Improve Seismic Source Parameter Determination/Event Location Accuracy

None
Date: July 5, 2012
Creator: Gok, R.; Herzog, S.; Nakanishi, K.; Pasyanos, M.; Mellors, R.; Rodgers, A. et al.
Object Type: Article
System: The UNT Digital Library
The "Fiscal Cliff": Macroeconomic Consequences of Tax Increases and Spending Cuts (open access)

The "Fiscal Cliff": Macroeconomic Consequences of Tax Increases and Spending Cuts

Report regarding the fiscal cliff, which is a set of tax increases and spending cuts that would substantially reduce the deficit in 2013.
Date: September 5, 2012
Creator: Gravelle, Jane G.
Object Type: Report
System: The UNT Digital Library
Unemployment: Issues in the 112th Congress (open access)

Unemployment: Issues in the 112th Congress

This report briefly reviews the situation in the 2012 labor market, expands on the policy steps taken to date, and analyzes policy issues that typically arise during consideration of stimulus legislation. Three policy issues are examined: whether to take additional measures to increase jobs, what measures might be most effective, and how job creation proposals should be financed.
Date: October 5, 2012
Creator: Gravelle, Jane G.; Hungerford, Thomas L. & Levine, Linda
Object Type: Report
System: The UNT Digital Library
Dispute Settlement in the World Trade Organization (WTO): An Overview (open access)

Dispute Settlement in the World Trade Organization (WTO): An Overview

None
Date: April 5, 2012
Creator: Grimmett, Jeanne J.
Object Type: Report
System: The UNT Digital Library
The War Powers Resolution: After Thirty-Eight Years (open access)

The War Powers Resolution: After Thirty-Eight Years

Report that discusses and assesses the War Powers Resolution and its application since enactment in 1973, providing detailed background on various cases in which it was used, as well as cases in which issues of its applicability were raised.
Date: September 5, 2012
Creator: Grimmett, Richard F.
Object Type: Report
System: The UNT Digital Library
Development of High Average Power Lasers for the Photon Collider (open access)

Development of High Average Power Lasers for the Photon Collider

The laser and optics system for the photon collider seeks to minimize the required laser power by using an optical stacking cavity to recirculate the laser light. An enhancement of between 300 to 400 is desired. In order to achieve this the laser pulses which drive the cavity must precisely match the phase of the pulse circulating within the cavity. We report on simulations of the performance of a stacking cavity to various variations of the drive laser in order to specify the required tolerances of the laser system.
Date: July 5, 2012
Creator: Gronberg, Jeff; /LLNL, Livermore; Stuart, Brent; /LLNL, Livermore; Seryi, Andrei & /SLAC
Object Type: Article
System: The UNT Digital Library
Conceptual Design - Polar Drive Ignition Campaign (open access)

Conceptual Design - Polar Drive Ignition Campaign

The Laboratory for Laser Energetics (LLE) at the University of Rochester is proposing a collaborative effort with Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratories (LANL), the Naval Research Laboratory (NRL), and General Atomics (GA) with the goal of developing a cryogenic polar drive (PD) ignition platform on the National Ignition Facility (NIF). The scope of this proposed project requires close discourse among theorists, experimentalists, and laser and system engineers. This document describes how this proposed project can be broken into a series of parallel independent activities that, if implemented, could deliver this goal in the 2017 timeframe. This Conceptual Design document is arranged into two sections: mission need and design requirements. Design requirements are divided into four subsystems: (1) A point design that details the necessary target specifications and laser pulse requirements; (2) The beam smoothing subsystem that describes the MultiFM 1D smoothing by spectral dispersion (SSD); (3) New optical elements that include continuous phase plates (CPP's) and distributed polarization rotators (DPR's); and (4) The cryogenic target handling and insertion subsystem, which includes the design, fabrication, testing, and deployment of a dedicated PD ignition target insertion cryostat (PD-ITIC). This document includes appendices covering: the primary criteria and functional …
Date: April 5, 2012
Creator: Hansen, R
Object Type: Report
System: The UNT Digital Library
Recent RHIC In-Situ Coating Technology Developments (open access)

Recent RHIC In-Situ Coating Technology Developments

N/A
Date: June 5, 2012
Creator: Hershcovitch, A.; Blaskiewicz, M.; Brennan, J. M.; Chawla, A.; Custer, A.; Erickson, M. et al.
Object Type: Article
System: The UNT Digital Library
Fundamental Physics at the Intensity Frontier. Report of the Workshop Held December 2011 in Rockville, MD. (open access)

Fundamental Physics at the Intensity Frontier. Report of the Workshop Held December 2011 in Rockville, MD.

Particle physics aims to understand the universe around us. The Standard Model of particle physics describes the basic structure of matter and forces, to the extent we have been able to probe thus far. However, it leaves some big questions unanswered. Some are within the Standard Model itself, such as why there are so many fundamental particles and why they have different masses. In other cases, the Standard Model simply fails to explain some phenomena, such as the observed matter-antimatter asymmetry in the universe, the existence of dark matter and dark energy, and the mechanism that reconciles gravity with quantum mechanics. These gaps lead us to conclude that the universe must contain new and unexplored elements of Nature. Most of particle and nuclear physics is directed towards discovering and understanding these new laws of physics. These questions are best pursued with a variety of approaches, rather than with a single experiment or technique. Particle physics uses three basic approaches, often characterized as exploration along the cosmic, energy, and intensity frontiers. Each employs different tools and techniques, but they ultimately address the same fundamental questions. This allows a multi-pronged approach where attacking basic questions from different angles furthers knowledge and provides …
Date: June 5, 2012
Creator: Hewett, J. L.; Weerts, H.; Brock, R.; Butler, J. N.; Casey, B. C. K.; Lu, Z. T. et al.
Object Type: Report
System: The UNT Digital Library
Advances in X-Band TW Accelerator Structures Operating in the 100 MV/M Regime (open access)

Advances in X-Band TW Accelerator Structures Operating in the 100 MV/M Regime

A CERN-SLAC-KEK collaboration on high gradient X-band accelerator structure development for CLIC has been ongoing for three years. The major outcome has been the demonstration of stable 100 MV/m gradient operation of a number of CLIC prototype structures. These structures were fabricated using the technology developed from 1994 to 2004 for the GLC/NLC linear collider initiative. One of the goals has been to refine the essential parameters and fabrication procedures needed to realize such a high gradient routinely. Another goal has been to develop structures with stronger dipole mode damping than those for GLC/NLC. The latter requires that the surface temperature rise during the pulse be higher, which may increase the breakdown rate. One structure with heavy damping has been RF processed and another is nearly finished. The breakdown rates of these structures were found to be higher by two orders of magnitude compared to those with equivalent acceleration mode parameters but without the damping features. This paper presents these results together with some of the earlier results from non-damped structures.
Date: July 5, 2012
Creator: Higo, Toshiyasu; Higashi, Yasuo; Matsumoto, Shuji; Yokoyama, Kazue; Adolphsen, Chris; Dolgashev, Valery et al.
Object Type: Article
System: The UNT Digital Library
Stereoscopic System of Coded Aperture Neutron Pad Cameras for Warhead Counting (open access)

Stereoscopic System of Coded Aperture Neutron Pad Cameras for Warhead Counting

Progress report presented at the RadSensing 2012 meeting, Albuquerque, New Mexico.
Date: June 5, 2012
Creator: I., Dioszegi
Object Type: Article
System: The UNT Digital Library
Gauge Properties Of The Guiding Center Variational Symplectic Integrator (open access)

Gauge Properties Of The Guiding Center Variational Symplectic Integrator

Recently, variational symplectic algorithms have been developed for the long-time simulation of charged particles in magnetic fields1-3. As a direct consequence of their derivation from a discrete variational principle, these algorithms have very good long-time energy conservation, as well as exactly preserving discrete momenta. We present stability results for these algorithms, focusing on understanding how explicit variational integrators can be designed for this type of system. It is found that for explicit algorithms an instability arises because the discrete symplectic structure does not become the continuous structure in the t → 0 limit. We examine how a generalized gauge transformation can be used to put the Lagrangian in the "antisymmetric discretization gauge," in which the discrete symplectic structure has the correct form, thus eliminating the numerical instability. Finally, it is noted that the variational guiding center algorithms are not electromagnetically gauge invariant. By designing a model discrete Lagrangian, we show that the algorithms are approximately gauge invariant as long as A and #30; are relatively smooth. A gauge invariant discrete Lagrangian is very important in a variational particle-in-cell algorithm where it ensures current continuity and preservation of Gauss's law4.
Date: March 5, 2012
Creator: J. Squire, H. Qin and W. Tang
Object Type: Report
System: The UNT Digital Library
Interim Report on SNP analysis and forensic microarray probe design for South American hemorrhagic fever viruses, tick-borne encephalitis virus, henipaviruses, Old World Arenaviruses, filoviruses, Crimean-Congo hemorrhagic fever viruses, Rift Valley fever (open access)

Interim Report on SNP analysis and forensic microarray probe design for South American hemorrhagic fever viruses, tick-borne encephalitis virus, henipaviruses, Old World Arenaviruses, filoviruses, Crimean-Congo hemorrhagic fever viruses, Rift Valley fever

The goal of this project is to develop forensic genotyping assays for select agent viruses, enhancing the current capabilities for the viral bioforensics and law enforcement community. We used a multipronged approach combining bioinformatics analysis, PCR-enriched samples, microarrays and TaqMan assays to develop high resolution and cost effective genotyping methods for strain level forensic discrimination of viruses. We have leveraged substantial experience and efficiency gained through year 1 on software development, SNP discovery, TaqMan signature design and phylogenetic signature mapping to scale up the development of forensics signatures in year 2. In this report, we have summarized the whole genome wide SNP analysis and microarray probe design for forensics characterization of South American hemorrhagic fever viruses, tick-borne encephalitis viruses and henipaviruses, Old World Arenaviruses, filoviruses, Crimean-Congo hemorrhagic fever virus, Rift Valley fever virus and Japanese encephalitis virus.
Date: June 5, 2012
Creator: Jaing, C & Gardner, S
Object Type: Report
System: The UNT Digital Library
Impacts of Antifoam Additions and Argon Bubbling on Defense Waste Processing Facility Reduction/Oxidation (open access)

Impacts of Antifoam Additions and Argon Bubbling on Defense Waste Processing Facility Reduction/Oxidation

During melting of HLW glass, the REDOX of the melt pool cannot be measured. Therefore, the Fe{sup +2}/{Sigma}Fe ratio in the glass poured from the melter must be related to melter feed organic and oxidant concentrations to ensure production of a high quality glass without impacting production rate (e.g., foaming) or melter life (e.g., metal formation and accumulation). A production facility such as the Defense Waste Processing Facility (DWPF) cannot wait until the melt or waste glass has been made to assess its acceptability, since by then no further changes to the glass composition and acceptability are possible. therefore, the acceptability decision is made on the upstream process, rather than on the downstream melt or glass product. That is, it is based on 'feed foward' statistical process control (SPC) rather than statistical quality control (SQC). In SPC, the feed composition to the melter is controlled prior to vitrification. Use of the DWPF REDOX model has controlled the balanjce of feed reductants and oxidants in the Sludge Receipt and Adjustment Tank (SRAT). Once the alkali/alkaline earth salts (both reduced and oxidized) are formed during reflux in the SRAT, the REDOX can only change if (1) additional reductants or oxidants are added …
Date: June 5, 2012
Creator: Jantzen, Carol M. & Johnson, F. C.
Object Type: Report
System: The UNT Digital Library
A NEW ALGORITHM FOR RADIOISOTOPE IDENTIFICATION OF SHIELDED AND MASKED SNM/RDD MATERIALS (open access)

A NEW ALGORITHM FOR RADIOISOTOPE IDENTIFICATION OF SHIELDED AND MASKED SNM/RDD MATERIALS

Detection and identification of shielded and masked nuclear materials is crucial to national security, but vast borders and high volumes of traffic impose stringent requirements for practical detection systems. Such tools must be be mobile, and hence low power, provide a low false alarm rate, and be sufficiently robust to be operable by non-technical personnel. Currently fielded systems have not achieved all of these requirements simultaneously. Transport modeling such as that done in GADRAS is able to predict observed spectra to a high degree of fidelity; our research is focusing on a radionuclide identification algorithm that inverts this modeling within the constraints imposed by a handheld device. Key components of this work include incorporation of uncertainty as a function of both the background radiation estimate and the hypothesized sources, dimensionality reduction, and nonnegative matrix factorization. We have partially evaluated performance of our algorithm on a third-party data collection made with two different sodium iodide detection devices. Initial results indicate, with caveats, that our algorithm performs as good as or better than the on-board identification algorithms. The system developed was based on a probabilistic approach with an improved approach to variance modeling relative to past work. This system was chosen based …
Date: June 5, 2012
Creator: Jeffcoat, R.
Object Type: Article
System: The UNT Digital Library
The suppression of magnetism and the development of superconductivity within the collapsed tetragonal phase of Ca0.67Sr0.33Fe2As2 at high pressure (open access)

The suppression of magnetism and the development of superconductivity within the collapsed tetragonal phase of Ca0.67Sr0.33Fe2As2 at high pressure

None
Date: March 5, 2012
Creator: Jeffries, J R; Butch, N P; Kirshenbaum, K; Saha, S R; Weir, S T; Vohra, Y K et al.
Object Type: Article
System: The UNT Digital Library