Release Data Package for the 2004 Composite Analysis (open access)

Release Data Package for the 2004 Composite Analysis

This data package contains all the key parameter data necessary for implementation of the Release Module to conduct the 2004 Composite Analysis. A composite analysis is required by DOE Order 435.1 to ensure public safety through the management of active and planned low-level radioactive waste disposal facilities associated with Hanford.
Date: August 2, 2004
Creator: Riley, Robert G. & Lopresti, Charles A.
Object Type: Report
System: The UNT Digital Library
Activation Cross Sections Improvements needed for IFE Power Reactors Designs (open access)

Activation Cross Sections Improvements needed for IFE Power Reactors Designs

Uncertainties in the prediction of the neutron induced long-lived activity in the natural elements from H to Bi due to activation cross section uncertainties are estimated assuming as neutron environment those of the HYLIFE-II and Sombrero vessel structures. The latest available activation cross section data are employed. The random variables used in the uncertainty analysis have been the concentration limits (CL's) corresponding to hands-on recycling, remote recycling and shallow land burial, quantities typically considered in ranking elements under waste management considerations. The CL standard value (CL{sub nom}), i.e. without uncertainties, is compared with the 95th percentile CL value (CL95). The results of the analysis are very helpful in assessing the quality of the current activation data for IFE applications, providing a rational basis for programmatic priority assignments for new cross sections measurements or evaluations. The HYLIFE-II results shown that a significant error is estimated in predicting the activation of several elements. The estimated errors in the Sombrero case are much less important.
Date: October 2, 2003
Creator: Rodriguez, A; Cabellos, O; Sanz, J; FalQuina, R; Latkowski, J & Reyes, S
Object Type: Article
System: The UNT Digital Library
The US ICF Ignition Program and the Inertial Fusion Program (open access)

The US ICF Ignition Program and the Inertial Fusion Program

There has been rapid progress in inertial fusion in the past few years. This progress spans the construction of ignition facilities, a wide range of target concepts, and the pursuit of integrated programs to develop fusion energy using lasers, ion beams and z-pinches. Two ignition facilities are under construction (NIF in the U.S. and LMJ in France) and both projects are progressing toward an initial experimental capability. The LIL prototype beamline for LMJ and the first 4 beams of NIF will be available for experiments in 2003. The full 192 beam capability of NIF will be available in 2009 and ignition experiments are expected to begin shortly after that time. There is steady progress in the target science and target fabrication in preparation for indirect drive ignition experiments on NIF. Advanced target designs may lead to 5-10 times more yield than initial target designs. There has also been excellent progress on the science of ion beam and z-pinch driven indirect drive targets. Excellent progress on direct-drive targets has been obtained on the Omega laser at the University of Rochester. This includes improved performance of targets with a pulse shape predicted to result in reduced hydrodynamic instability. Rochester has also obtained …
Date: July 2, 2003
Creator: Lindl, J. D.; Hammel, B. A.; Logan, B. G.; Meyerhofer, D. D.; Payne, S. A. & Stehian, J. D.
Object Type: Article
System: The UNT Digital Library
Quarterly Report 9/30/03 (open access)

Quarterly Report 9/30/03

In this quarter, LLNL personnel traveled to the Alcoa Technical Center to discuss the current status of simulations and experiments. The previously-noted deficiencies of the fracture model were discussed in detail as were ways to improve its functional form to ensure reasonable behavior over a wider range of pressures and strain rates. Additional experiments to calibrate the model at low strain rates and high triaxiality were reviewed. We expect that ATC will provide the refined fracture model to LLNL shortly. Once available, appropriate modifications will be made in the FEM subroutines, and the validation process for ingot fracture will continue. A simulation is being performed to validate the FEM model for a production facility mill configuration. The current focus is on the evolution of the deformed slab shape with increasing number of reduction passes. A detailed comparison of the slab side profile with experimental results is currently being carried out to identify key parameters controlling the simulated shape. Preliminary results show that the friction model plays a dominant role in the intermediate and final profile shapes. Using details of the deformed shape as a validation metric, additional simulations will be performed to optimize parameter values.
Date: October 2, 2003
Creator: Couch, R G
Object Type: Report
System: The UNT Digital Library
Computational Chemistry for Nuclear Waste Characterization and Processing: Relativistic Quantum Chemistry of Actinides (open access)

Computational Chemistry for Nuclear Waste Characterization and Processing: Relativistic Quantum Chemistry of Actinides

In the course of the 3 years we have conducted calculations on molecular structures containing actinides, lanthanides, and other heavy elements. Our calculations were done at the relativistically-correct, all-electron, 4-component calculations (DHF, MP2, and CCSD(T)), using density functional theory (DFT) with relativistic effective core potentials (RECPs), and various other methodologies. We studied the ground- and excited state structures, energetics, vibrational frequencies, and NMR, excitation and ionization spectra. In addition a considerable amount of codes and methodologies have been developed during the GC3 period, enabling us to do the extensive research described in this final report, and providing researchers worldwide with new computational chemistry tools. In this section we will give a brief overview of our activities and accomplishments, grouped by each research institution. A more extensive overview can be found in the appendices containing the full yearly reports.
Date: August 2, 2002
Creator: Harrison, Robert J.; Bernholdt, David E.; Bursten, Bruce E.; De Jong, Wibe A.; Dixon, David A.; Dyall, Kenneth G. et al.
Object Type: Report
System: The UNT Digital Library
DISTINGUISHING SPONTANEOUS FISSION NEUTRONS FROM COSMIC-RAY BACKGROUND. (open access)

DISTINGUISHING SPONTANEOUS FISSION NEUTRONS FROM COSMIC-RAY BACKGROUND.

We have measured the neutron spectra of cosmic-rays and a spontaneous fission emitting source (Cf-252) using a neutron double scatter spectrometer. The energy range of measurements was 0.1-10 MeV where the spectrometer efficiency is determined to be up to 8.7% depending on the separation between detection planes. Our cosmic-ray neutron spectrum measurement is in good agreement with the sea-level data reported by Goldhagen and his co-workers. In the energy range 0.1-1.0 MeV, the cosmic-ray and Cf-252 spectra are different and separable. This difference is expected from the applicable models that describe the phenomena, ''equilibrium slowing down'' (cosmic-rays) and ''Maxwellian kinetic temperature'' emission (spontaneous fission). We show that >80% of Cf-252 neutrons and <25% of cosmic-ray related neutrons are emitted in this energy range of measurement, and conclude that neutron spectroscopy provides effective ways to distinguish a fission source from the cosmic-ray background.
Date: August 2, 2004
Creator: FORMAN,L.
Object Type: Article
System: The UNT Digital Library
Higgs Boson Resummation via Bottom-Quark Fusion. (open access)

Higgs Boson Resummation via Bottom-Quark Fusion.

The region of small transverse momentum in q{bar q} and gg-initiated processes must be studied in the framework of resummation to account for the large, logarithmically-enhanced contributions to physical observables. In this letter, we study resummed differential cross-sections for Higgs production via bottom-quark fusion. We find that the differential distribution peaks at approximately 15 GeV, a number of great experimental importance to measuring this production channel.
Date: May 2, 2005
Creator: Field, B.
Object Type: Article
System: The UNT Digital Library
P-wave arrival times for the 1991 racha, Georgia earthquake sequence at stations of a test, sparse network (open access)

P-wave arrival times for the 1991 racha, Georgia earthquake sequence at stations of a test, sparse network

The following arrival information is a supplement to Myers and Schultz (2000). Myers and Schultz (2000) demonstrate the improvement in sparse-network location that can be achieved by using travel-time corrections determined with a Bayesian Kriging algorithm (Schultz et al., 1998). Precise, benchmark locations are provided by a local aftershock study of the 1991 Racha, Georgia earthquake sequence in the Caucasus Mountains (Fuenzalida et al., 1997). A test network is used to relocate the aftershocks with and without travel-time corrections. The test network is meant to represent a typical International Monitoring System configuration, with 6 stations at regional to near teleseismic distances (less then 30{sup o} from the epicenter). The following arrival-time data help to facilitate the reproduction of Myers and Schultz (2000). The arrival picks were obtained from the International Seismic Center (ISC) (openly available) and a Lawrence Livermore National Laboratory (LLNL) analyst (Flori Ryan). Table 1 lists the arrivals in epic time (time since January 1, 1970). The author of the arrival pick is listed as either ''flori'' or ''-'', where ''-'' indicates ISC. Table 2 lists the hypocenter information determined in the local aftershock study of Fuenzalida et al. (1997), and Table 3 lists the station information for …
Date: February 2, 2000
Creator: Myers, S C; Schultz, C A & Ryall, F
Object Type: Report
System: The UNT Digital Library
Laboratory Directed Research and Development FY2002 Annual Report (open access)

Laboratory Directed Research and Development FY2002 Annual Report

None
Date: May 2, 2003
Creator: Al-Ayat, R
Object Type: Report
System: The UNT Digital Library
Plasma Diagnostics in High Resolution X-Ray Spectra of Magnetic Cataclysmic Variables (open access)

Plasma Diagnostics in High Resolution X-Ray Spectra of Magnetic Cataclysmic Variables

Using the Chandra HETG spectrum of EX Hya as an example, we discuss some of the plasma diagnostics available in high-resolution X-ray spectra of magnetic cataclysmic variables. Specifically, for conditions appropriate to collisional ionization equilibrium plasmas, we discuss the temperature dependence of the H- to He-like line intensity ratios and the density and photoexcitation dependence of the He-like R line ratios and the Fe XVII I(17.10 {angstrom})/I(17.05 {angstrom}) line ratio. We show that the plasma temperature in EX Hya spans the range from {approx}0.5 to {approx}10 keV and that the plasma density n {ge} 2 x 10{sup 14} cm{sup -3}, orders of magnitude greater than that observed in the Sun or other late-type stars.
Date: October 2, 2001
Creator: Mauche, Christopher W.
Object Type: Article
System: The UNT Digital Library
RIA Fragmentation Line Beam Dump (open access)

RIA Fragmentation Line Beam Dump

The Rare Isotope Accelerator project involves generating heavy element ion beams for use in a fragmentation target line to produce selected ion beams for physics research experiments. The main beam and fission fragments, after passing through the target, are collected and passed along by a series of collecting magnets and a dipole magnet. In the first dipole magnet, the main beam impacts onto a beam dump located on each side of the magnet vacuum chamber. A dump design that involves rotating cylinders and internal water cooling passages has been designed to absorb the glancing impact of the main beam. The beam power designed for is 100 kW and water cooling is by turbulent sub-cooled forced convection.
Date: May 2, 2003
Creator: Stein, W.
Object Type: Article
System: The UNT Digital Library
Excitations, optical absorption spectra, and optical excitonic gaps of heterofullerenes: I. C60, C59N+ and C48N12 (open access)

Excitations, optical absorption spectra, and optical excitonic gaps of heterofullerenes: I. C60, C59N+ and C48N12

Low-energy excitations and optical absorption spectrum of C{sub 60} are computed by using time-dependent (TD) Hartree-Fock (HF), TD-density functional theory (TD-DFT), TD-DFT-based tight-binding (TD-DFT-TB) and a semiempirical ZINDO method. A detailed comparison of experiment and theory for the excitation energies, optical gap and absorption spectrum of C{sub 60} is presented. It is found that electron correlations and collective effects of exciton pairs play important roles in assigning accurately the spectral features of C{sub 60} and the TD-DFT method with non-hybrid functionals or a local spin density approximation leads to more accurate excitation energies than with hybrid functionals. The level of agreement between theory and experiment for C{sub 60} justifies similar calculations of the excitations and optical absorption spectrum of a monomeric azafullerene cation C{sub 59}N{sup +} exhibits distinguishing spectral features different from C{sub 60}: (1) the first singlet is dipole-allowed and the optical gap is redshifted by 1.44 eV; (2) several weaker absorption maxima occur in the visible region; (3) the transient triplet-triplet absorption at 1.60 eV (775 nm) is much broader and the decay of the triplet state is much faster. The calculated spectra of C{sub 59}N{sup +} characterize and explain well our measured ultraviolet-visible (UV-vis) and transient absorption …
Date: October 2, 2003
Creator: Xie, Rui-Hua; Bryant, Garnett W.; Sun, Guangyu; Nicklaus, Mark C.; Heringer, David; Frauenheim, Th. et al.
Object Type: Article
System: The UNT Digital Library
Discovery and Classification of Bioinformatics Web Services (open access)

Discovery and Classification of Bioinformatics Web Services

The transition of the World Wide Web from a paradigm of static Web pages to one of dynamic Web services provides new and exciting opportunities for bioinformatics with respect to data dissemination, transformation, and integration. However, the rapid growth of bioinformatics services, coupled with non-standardized interfaces, diminish the potential that these Web services offer. To face this challenge, we examine the notion of a Web service class that defines the functionality provided by a collection of interfaces. These descriptions are an integral part of a larger framework that can be used to discover, classify, and wrapWeb services automatically. We discuss how this framework can be used in the context of the proliferation of sites offering BLAST sequence alignment services for specialized data sets.
Date: September 2, 2002
Creator: Rocco, D. & Critchlow, T.
Object Type: Article
System: The UNT Digital Library
Stochastic Engine: Direct Incorporation of Measurements Into Predictive Simulations (open access)

Stochastic Engine: Direct Incorporation of Measurements Into Predictive Simulations

We are creating a new method of combining disparate types of geologic observations and process simulations. Using Bayesian inferencing and an efficient search algorithm, we obtain a consolidated body of knowledge in the form of multiple configurations and parameter values of the system that are consistent with our existing data and process models. In so doing, we effectively estimate the distributions of both individual parameters and system-wide states, and their likelihood of occurrence. This is in contrast with conventional inversion methods, which produce a single deterministic understanding lacking quantitative information about the distribution of uncertainty. We call this combination of probabilistic evaluation and deterministic process simulators the stochastic engine. Our approach allows the investigators to rapidly improve their understanding of system progress, making it particularly valuable for active processes like injection. The Bayesian inferencing is driven by forward process models that predict data values, such as temperature or electrical voltage, for direct comparison to measured field values. We stage the stochastic searches of possible configurations and run the simplest models, such as lithology estimators, at the lower stages. The majority of possible configurations are eliminated from further consideration by the higher stages' more complex models, such as electrical resistance models …
Date: August 2, 2001
Creator: Newmark, R. L.; Aines, R. D.; Nitao, J. J.; Hanley, W. G.; Carle, S.; Ramirez, A. L. et al.
Object Type: Article
System: The UNT Digital Library
Toward the Automated Generation of Components from Existing Source Code (open access)

Toward the Automated Generation of Components from Existing Source Code

A major challenge to achieving widespread use of software component technology in scientific computing is an effective migration strategy for existing, or legacy, source code. This paper describes initial work and challenges in automating the identification and generation of components using the ROSE compiler infrastructure and the Babel language interoperability tool. Babel enables calling interfaces expressed in the Scientific Interface Definition Language (SIDL) to be implemented in, and called from, an arbitrary combination of supported languages. ROSE is used to build specialized source-to-source translators that (1) extract a SIDL interface specification from information implicit in existing C++ source code and (2) transform Babel's output to include dispatches to the legacy code.
Date: December 2, 2004
Creator: Quinlan, Daniel; Yi, Qing; Kumfert, Gary; Epperly, Thomas; Dahlgren, Tamara; Schordan, Markus et al.
Object Type: Article
System: The UNT Digital Library
Employing Thin HPGe Detectors for Gamma-Ray Imaging (open access)

Employing Thin HPGe Detectors for Gamma-Ray Imaging

We have evaluated a collimator-less gamma-ray imaging system, which is based on thin layers of double-sided strip HPGe detectors. The positions of individual gamma-ray interactions will be deduced by the strip addresses and the Ge layers which fired. Therefore, high bandwidth pulse processing is not required as in thick Ge detectors. While the drawback of such a device is the increased number of electronics channels to be read out and processed, there are several advantages, which are particularly important for remote applications: the operational voltage can be greatly reduced to fully deplete the detector and no high bandwidth signal processing electronics is required to determine positions. Only a charge sensitive preamplifier, a slow pulse shaping amplifier, and a fast discriminator are required on a per channel basis in order to determine photon energy and interaction position in three dimensions. Therefore, the power consumption and circuit board real estate can be minimized. More importantly, since the high bandwidth signal shapes are not used to determine the depth position, lower energy signals can be processed. The processing of these lower energy signals increases the efficiency for the recovery of small angle scattering. Currently, we are studying systems consisting of up to ten …
Date: May 2, 2002
Creator: Vetter, K.; Mihailescu, L.; Ziock, K.; Burks, M.; Hull, E.; Madden, N. et al.
Object Type: Article
System: The UNT Digital Library