SUPPORTING SAFE STORAGE OF PLUTONIUM-BEARING MATERIALS THROUGH SCIENCE, ENGINEERING AND SURVEILLANCE (open access)

SUPPORTING SAFE STORAGE OF PLUTONIUM-BEARING MATERIALS THROUGH SCIENCE, ENGINEERING AND SURVEILLANCE

Reductions in the size of the U. S. nuclear weapons arsenal resulted in the need to store large quantities of plutonium-bearing metals and oxides for prolonged periods of time. To assure that the excess plutonium from the U. S. Department of Energy (DOE) sites was stored in a safe and environmentally friendly manner the plutonium-bearing materials are stabilized and packaged according to well developed criteria published as a DOE Standard. The packaged materials are stored in secure facilities and regular surveillance activities are conducted to assure continuing package integrity. The stabilization, packaging, storage and surveillance requirements were developed through extensive science and engineering activities including those related to: plutonium-environment interactions and container pressurization, corrosion and stress corrosion cracking, plutonium-container material interactions, loss of sealing capability and changes in heat transfer characteristics. This paper summarizes some of those activities and outlines ongoing science and engineering programs that assure continued safe and secure storage of the plutonium-bearing metals and oxides.
Date: November 10, 2009
Creator: Dunn, K.; Chandler, G.; Gardner, C.; Louthan, M. & Mcclard, J.
System: The UNT Digital Library
Design of pulse stretching cell for a sodium guide star optical system (open access)

Design of pulse stretching cell for a sodium guide star optical system

A pulse stretcher has been designed for the LLNL sodium guide star experiment to lower the laser flux and avoid saturation effects. The optical design, mechanical layout and wavefront error analysis are presented.
Date: November 10, 1992
Creator: Friedman, H. W.; Horton, J. A.; Kuklo, T. J. & Wong, N. J.
System: The UNT Digital Library
Neutral-beam systems for magnetic-fusion reactors (open access)

Neutral-beam systems for magnetic-fusion reactors

Neutral beams for magnetic fusion reactors are at an early stage of development, and require considerable effort to make them into the large, reliable, and efficient systems needed for future power plants. To optimize their performance to establish specific goals for component development, systematic analysis of the beamlines is essential. Three ion source characteristics are discussed: arc-cathode life, gas efficiency, and beam divergence, and their significance in a high-energy neutral-beam system is evaluated.
Date: August 10, 1981
Creator: Fink, J. H.
System: The UNT Digital Library
A Split-Function Lattice for Stochastic Cooling (open access)

A Split-Function Lattice for Stochastic Cooling

Lattice for a 3-GeV cooler ring with split functions is presented. The ring consists of two half-rings of different properties: in one half-ring, the phase-slip factor is near-zero; in the other half-ring, the phase-slip factor is large. The near-zero phase slip minimizes the 'bad mixing' between the stochastic-cooling pick-ups and kickers, while the high phase slip maximizes the 'good mixing' between the kickers and the next-turn pick-ups.
Date: September 10, 2007
Creator: Wei, J.
System: The UNT Digital Library
Extensional wave attenuation and velocity in partially saturated sand in the sonic frequency range (open access)

Extensional wave attenuation and velocity in partially saturated sand in the sonic frequency range

Extensional wave attenuation and velocity measurements on a high permeability Monterey sand were performed over a range of gas saturations for imbibition and degassing conditions. These measurements were conducted using extensional wave pulse propagation and resonance over a 1-9 kHz frequency range for a hydrostatic confining pressure of 8.3 MPa. Analysis of the extensional wave data and the corresponding X-ray CT images of the gas saturation show strong attenuation resulting from the presence of the gas (Q{sub E} dropped from 300 for the dry sand to 30 for the partially-saturated sand), with larger attenuation at a given saturation resulting from heterogeneous gas distributions. The extensional wave velocities are in agreement with Gassmann theory for the test with near-homogeneous gas saturation and with a patchy saturation model for the test with heterogeneous gas saturation. These results show that partially-saturated sands under moderate confining pressure can produce strong intrinsic attenuation for extensional waves.
Date: August 10, 2001
Creator: Liu, Z.; Rector, J. W.; Nihei, K. T.; Tomutsa, L.; Myer, L. R. & Nakagawa, S.
System: The UNT Digital Library
Novel High Transverse Momentum Phenomena in Hadronic and Nuclear Collisions (open access)

Novel High Transverse Momentum Phenomena in Hadronic and Nuclear Collisions

I discuss a number of novel phenomenological features of QCD in high transverse momentum reactions. The presence of direct higher-twist processes, where a proton is produced directly in the hard subprocess, can explain the 'baryon anomaly' - the large proton-to-pion ratio seen at RHIC in high centrality heavy ion collisions. Direct hadronic processes can also account for the deviation from leading-twist PQCD scaling at fixed x{sub T} = 2 p{sub T}/{radical}s. I suggest that the 'ridge' --the same-side long-range rapidity correlation observed at RHIC in high centrality heavy ion collisions is due to the imprint of semihard DGLAP gluon radiation from initial-state partons which have transverse momenta biased toward the trigger. A model for early thermalization of the quark-gluon medium is also outlined. Rescattering interactions from gluon-exchange, normally neglected in the parton model, have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, the breakdown of the Lam-Tung relation in Drell-Yan reactions, nuclear shadowing--all leading-twist dynamics not incorporated in the light-front wavefunctions of the target computed in isolation. Anti shadowing is shown to be quark flavor specific and thus different in charged and neutral deep inelastic lepton-nucleus scattering. I …
Date: April 10, 2009
Creator: Brodsky, Stanley J.
System: The UNT Digital Library
Slug flow model for infiltration into fractured porous media (open access)

Slug flow model for infiltration into fractured porous media

A model for transient infiltration into a periodically fractured porous layer is presented. The fracture is treated as a permeable-walled slot and the moisture distribution is in the form of a slug being an advancing meniscus. The wicking of moisture from the fracture to the unsaturated porous matrix is a nonlinear diffusion process and is approximately by self-similar solutions. The resulting model is a nonlinear Volterra integral equation with a weakly singular kernel. Numerical analysis provides solutions over a wide range of the parameter space and reveals the asymptotic forms of the penetration of this slug in terms of dimensionless variables arising in the model. The numerical solutions corroborate asymptotic results given earlier by Nitao and Buscheck (1991), and by Martinez (1988). Some implications for the transport of liquid in fractured rock are discussed.
Date: November 10, 1999
Creator: Martinez, M.J.
System: The UNT Digital Library
National Ignition Facility Target Design and Fabrication (open access)

National Ignition Facility Target Design and Fabrication

The current capsule target design for the first ignition experiments at the NIF Facility beginning in 2009 will be a copper-doped beryllium capsule, roughly 2 mm in diameter with 160-{micro}m walls. The capsule will have a 75-{micro}m layer of solid DT on the inside surface, and the capsule will driven with x-rays generated from a gold/uranium cocktail hohlraum. The design specifications are extremely rigorous, particularly with respect to interfaces, which must be very smooth to inhibit Rayleigh-Taylor instability growth. This paper outlines the current design, and focuses on the challenges and advances in capsule fabrication and characterization; hohlraum fabrication, and D-T layering and characterization.
Date: December 10, 2007
Creator: Cook, R. C.; Kozioziemski, B. J.; Nikroo, A.; Wilkens, H. L.; Bhandarkar, S.; Forsman, A. C. et al.
System: The UNT Digital Library
The RHIC and RHIC Pre-Injectors Controls Systems: Status and Plans (open access)

The RHIC and RHIC Pre-Injectors Controls Systems: Status and Plans

For the past twelve years experiments at the Relativistic Heavy Ion Collider (RHIC) have recorded data from collisions of heavy ions and polarized protons, leading to important discoveries in nuclear physics and the spin dynamics of quarks and gluons. BNL is the site of one of the first and still operating alternating gradient synchrotrons, the AGS, which first operated in 1960. The accelerator controls systems for these instruments span multiple generations of technologies. In this report we will describe the current status of the Collider-Accelerator Department controls systems, which are used to control seven different accelerator facilities and multiple science programs (high energy nuclear physics, high energy polarized proton physics, NASA programs, isotope production, and multiple accelerator research and development projects). We will describe the status of current projects, such as the just completed Electron Beam Ion Source (EBIS), our R&D programs in superconducting RF and an Energy Recovery LINAC (ERL), innovations in feedback systems and bunched beam stochastic cooling at RHIC, and plans for future controls system developments.
Date: October 10, 2011
Creator: Brown, K. A.; Altinbas, Z.; Aronson, J.; Binello, S.; Campbell, I.; Costanzo, M. et al.
System: The UNT Digital Library
VERTIGO (VERtical Transport In the Global Ocean): A study of particle sources and flux attenuation in the North Pacific (open access)

VERTIGO (VERtical Transport In the Global Ocean): A study of particle sources and flux attenuation in the North Pacific

The VERtical Transport In the Global Ocean (VERTIGO) study examined particle sources and fluxes through the ocean's 'twilight zone' (defined here as depths below the euphotic zone to 1000 m). Interdisciplinary process studies were conducted at contrasting sites off Hawaii (ALOHA) and in the NW Pacific (K2) during 3 week occupations in 2004 and 2005, respectively. We examine in this overview paper the contrasting physical, chemical and biological settings and how these conditions impact the source characteristics of the sinking material and the transport efficiency through the twilight zone. A major finding in VERTIGO is the considerably lower transfer efficiency (T{sub eff}) of particulate organic carbon (POC), POC flux 500/150 m, at ALOHA (20%) vs. K2 (50%). This efficiency is higher in the diatom-dominated setting at K2 where silica-rich particles dominate the flux at the end of a diatom bloom, and where zooplankton and their pellets are larger. At K2, the drawdown of macronutrients is used to assess export and suggests that shallow remineralization above our 150 m trap is significant, especially for N relative to Si. We explore here also surface export ratios (POC flux/primary production) and possible reasons why this ratio is higher at K2, especially during the …
Date: June 10, 2008
Creator: Buesseler, K. O.; Trull, T. W.; Steinberg, D. K.; Silver, M. W.; Siegel, D. A.; Saitoh, S. I. et al.
System: The UNT Digital Library
2012 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies (open access)

2012 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

This Research is about Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies which presents a preliminary model of the three-dimensional seismic structure of the Iran region.
Date: September 10, 2012
Creator: Wetovsky, Marvin A.; Anderson, Dale; Arrowsmith, Stephen J.; Begnaud, Michael L.; Hartse, Hans E.; Maceira, Monica et al.
System: The UNT Digital Library
Progress in Fast Ignitor Research With the Nova Petawatt Laser Facility (open access)

Progress in Fast Ignitor Research With the Nova Petawatt Laser Facility

The physics of fast ignition is being studied using a petawatt laser facility at the Lawrence Livermore National Laboratory. Performance of the PW laser with deformable mirror wavefront control giving intensities up to 3x10{sup 20} Wcm{sup {minus}2} is described. Measurements of the efficiency of conversion of laser energy to relativistic electrons and of their energy spectrum and angular distribution including an observed narrow beam angle of {+-}15{degree}, are reported. Heating by the electrons to near 1keV in solid density CD{sub 2} is inferred from the thermo-nuclear neutron yield. Estimates suggest an optimized gain of 300x if the National Ignition Facility were to be adapted for fast ignition.
Date: November 10, 1998
Creator: Cowan, T. E.; Hammel, B. A.; Hatchett, S. P.; Henry, E. A.; Key, M. H.; Kilkenny, J. D. et al.
System: The UNT Digital Library
Scaling Supernova Hydrodynamics to the Laboratory (open access)

Scaling Supernova Hydrodynamics to the Laboratory

Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, they are attempting to rigorously scale the physics of the laboratory in supernova. The scaling of hydrodynamics on microscopic laser scales to hydrodynamics on the SN-size scales is presented and requirements established. Initial results were reported in [1]. Next the appropriate conditions are generated on the NOVA laser. 10-15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth, due to the Richtmyer-Meshkov instability and to the Rayleigh-Taylor instability as the interface decelerates is generated. This scales the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few x10{sup 3} s. The experiment is modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS. Results of the experiments and simulations are presented. Analysis of the spike bubble velocities using potential flow theory and Ott thin shell theory is presented, as well as a study of 2D vs. 3D difference in growth at the He-H interface of Sn 1987A.
Date: November 10, 1998
Creator: Kane, J. O.; Remington, B. A.; Arnett, D.; Fryxell, B. A. & Drake, R. P.
System: The UNT Digital Library
Novel synthesis of [11C]GVG (Vigabatgrin) for pharmacokinetic studies of addiction treatment (open access)

Novel synthesis of [11C]GVG (Vigabatgrin) for pharmacokinetic studies of addiction treatment

We report here a novel synthetic route to prepare the precursor and to efficiently label GVG with C-11. 5-Bromo-3-(carbobenzyloxy)amino-1-pentene was synthesized in five steps from homoserine lactone. This was used in a two step radiosynthesis, displacement with [{sup 11}C]cyanide followed by acid hydrolysis to afford [{sup 11}C]GVG with high radiochemical yields (> 35%, not optimized) and high specific activity (2-5 Ci/{micro}mol). The [{sup 11}C]cyanide trapping was achieved at {minus}5 C with a mixture of Kryptofix and K{sub 2}CO{sub 3} without using conventional aqueous trapping procedure [7]. At this temperature, the excess NH{sub 3} from the target that may interfere with the synthesis would not be trapped [8]. This procedure would be advantageous to any moisture sensitive radiosynthetic steps, as it was the case for our displacement reaction. When conventional aqueous trapping procedure was used, any trace amount of water left, even after prolonged heating, resulted in either no reaction or extremely low yields for the displacement reaction. The entire synthetic procedure should be extendible to the labeling of the pharmacologically active S- form of GVG when using S-homoserine lactone.
Date: June 10, 2001
Creator: Ding, Y. S.; Studenov, A. R.; Zhang, Z.; Gerasimov, M.; Schiffer, W.; Dewey, S. L. et al.
System: The UNT Digital Library
Actinide tetra-N-heterocyclic carbene ‘sandwiches’ (open access)

Actinide tetra-N-heterocyclic carbene ‘sandwiches’

Article preparing highly-symmetrical, thorium and uranium octakis-carbene ‘sandwich’ complexes by ‘sandwiching’ the An(IV) cations between two anionic macrocyclic tetra-NHC ligands. The complexes are characterized by a range of experimental methods and DFT calculations.
Date: May 10, 2021
Creator: DeJesus, Joseph F.; Kerr, Ryan W. F.; Penchoff, Deborah A.; Carroll, Xian B.; Peterson, Charles C.; Arnold, Polly L. et al.
System: The UNT Digital Library
Magnetic frustration effects in uranium intermetallics (open access)

Magnetic frustration effects in uranium intermetallics

The effect of geometrical frustration on the development of the heavy-fermion state and quantum criticality is studied in UAuCu{sub 4}, UAuPt{sub 4}, UAu{sub 3}Ni{sub 2} samples through measurements of their magnetic susceptibility, heat capacity, and electrical resistivity. In addition, since lattice disorder can play a large role in defining magnetic properties in frustrated systems, extended X-ray absorption fine structure (EXAFS) data have also been obtained. The local structure results show a strong correlation with the magnetic properties in these samples.
Date: June 10, 2010
Creator: Jiang, Yu; Booth, C. H.; Tobash, P. H.; Gofryk, K.; Torrez, M. A.; Ronning, F. et al.
System: The UNT Digital Library
Luminosity Determination in pp Collisions at sqrt(s)=7 TeV Using the ATLAS Detector at the LHC (open access)

Luminosity Determination in pp Collisions at sqrt(s)=7 TeV Using the ATLAS Detector at the LHC

None
Date: June 10, 2013
Creator: Aad, Georges
System: The UNT Digital Library
33rd Actinide Separations Conference (open access)

33rd Actinide Separations Conference

None
Date: June 10, 2009
Creator: McDonald, L M & Dodson, K E
System: The UNT Digital Library
Impact of the implementation of MPI point-to-point communications on the performance of two general sparse solvers (open access)

Impact of the implementation of MPI point-to-point communications on the performance of two general sparse solvers

We examine the mechanics of the send and receive mechanism of MPI and in particular how we can implement message passing in a robust way so that our performance is not significantly affected by changes to the MPI system. This leads us to using the Isend/Irecv protocol which will entail sometimes significant algorithmic changes. We discuss this within the context of two different algorithms for sparse Gaussian elimination that we have parallelized. One is a multifrontal solver called MUMPS, the other is a supernodal solver called SuperLU. Both algorithms are difficult to parallelize on distributed memory machines. Our initial strategies were based on simple MPI point-to-point communication primitives. With such approaches, the parallel performance of both codes are very sensitive to the MPI implementation, the way MPI internal buffers are used in particular. We then modified our codes to use more sophisticated nonblocking versions of MPI communication. This significantly improved the performance robustness (independent of the MPI buffering mechanism) and scalability, but at the cost of increased code complexity.
Date: October 10, 2001
Creator: Amestoy, Patrick R.; Duff, Iain S.; L'Excellent, Jean-Yves & Li, Xiaoye S.
System: The UNT Digital Library
2012 ELECTRON DONOR-ACCEPTOR INTERACTIONS GORDON RESEARCH CONFERENCE, AUGUST 5-10, 2012 (open access)

2012 ELECTRON DONOR-ACCEPTOR INTERACTIONS GORDON RESEARCH CONFERENCE, AUGUST 5-10, 2012

The upcoming incarnation of the Gordon Research Conference on Electron Donor Acceptor Interactions will feature sessions on classic topics including proton-coupled electron transfer, dye-sensitized solar cells, and biological electron transfer, as well as emerging areas such as quantum coherence effects in donor-acceptor interactions, spintronics, and the application of donor-acceptor interactions in chemical synthesis.
Date: August 10, 2012
Creator: McCusker, James
System: The UNT Digital Library
Detecting exposure to environmental organic toxins in individual cells: towards development of a micro-fabricated device (open access)

Detecting exposure to environmental organic toxins in individual cells: towards development of a micro-fabricated device

A new method is being developed to quickly screen for the human exposure potential to polycyclic aromatic hydrocarbons (PAHs) and organochlorines (OCs). The development involves two key elements: identifying suitable signals that represent intracellular changes that are specific to PAH and OC exposure, and constructing a device to guide the biological cell growth so that signals from individual cells are consistent and reproducible. We are completing the identification of suitable signals by using synchrotron radiation-based (SR) Fourier-transform infrared (FTIR) spectromicroscopy in the mid-infrared region (4000-400 cm-1). Distinct changes have been observed in the IR spectra after treatment of human cells in culture medium with PAHs and OCs. The potential use of this method for detecting exposure to PAHs and OCs has been tested and compared to a reverse transcription polymerase chain reaction (RT-PCR) assay that quantifies increased expression of the CYP1A1 gene in response to exposu re to PAHs or OCs.
Date: January 10, 1999
Creator: Holman, Hoi-Ying N.; Zhang, Miqin; Goth-Goldstein, Regine; Martin, Michael C.; Russell, Marion; McKinney, Wayne R. et al.
System: The UNT Digital Library
The Effect of Soil Heterogeneity on the Transport of Bacteria for Bioaugmentation (open access)

The Effect of Soil Heterogeneity on the Transport of Bacteria for Bioaugmentation

None
Date: January 10, 2001
Creator: Kinsall, B.L.
System: The UNT Digital Library
Measurement of fragmentation and functionalization pathways in the multistep heterogeneous oxidation of organic aerosol (open access)

Measurement of fragmentation and functionalization pathways in the multistep heterogeneous oxidation of organic aerosol

The competition between the addition of polar, oxygen-containing functional groups (functionalization) and the cleavage of C-C bonds (fragmentation) has a governing influence on the change in volatility of organic species upon atmospheric oxidation, and hence on the loading of tropospheric organic aerosol. However the branching between these two channels is generally poorly constrained for oxidized organics. Here we determine functionalization/fragmentation branching ratios for organics spanning a range of oxidation levels, using the heterogeneous oxidation of squalane (C30H62) as a model system. Squalane particles are exposed to high concentrations of OH in a flow reactor, and measurements of particle mass and elemental ratios enable the determination of absolute elemental composition (number of oxygen, carbon, and hydrogen atoms) of the oxidized particles. At low OH exposures, the oxygen content of the organics increases, indicating that functionalization dominates, whereas at higher exposures the amount of carbon in the particles decreases, indicating the increasing importance of fragmentation processes. Once the organics are moderately oxidized (O/C~;;0.4), fragmentation completely dominates, and the increase in O/C ratio upon further oxidation is due to the loss of carbon rather than the addition of oxygen. These results suggest that fragmentation reactions may be key steps in the atmospheric formation …
Date: March 10, 2009
Creator: Kroll, Jesse H.; Smith, Jared D.; Che, Dung L.; Kessler, Sean H.; Worsnop, Douglas R. & Wilson, Kevin R.
System: The UNT Digital Library
7th ICFA mini-workshop on high intensity high brightness hadron beams (open access)

7th ICFA mini-workshop on high intensity high brightness hadron beams

None
Date: October 10, 2000
Creator: Mokhov, Nikolai V. & Chou, Weiren
System: The UNT Digital Library