5th Biotechnological Investigations Ocean Margins Program (open access)

5th Biotechnological Investigations Ocean Margins Program

BI-OMP supports DOE's mission in Climate Change Research. The program provides the fundamental understanding of the linkages between carbon and nitrogen cycles in ocean margins. Researchers are providing a mechanistic understanding of these cycles, using the tools of modern molecular biology. The models that will allow policy makers to determine safe levels of greenhouse gases for the Earth System.
Date: January 8, 2004
Creator: Massol, Arturo & Buxeda, Rosa
Object Type: Article
System: The UNT Digital Library
Formulation of the Linear Response Theory in Relativistic LAPW Method. Calculation of Forces in Alpha-Pu (open access)

Formulation of the Linear Response Theory in Relativistic LAPW Method. Calculation of Forces in Alpha-Pu

Linear-response (LR) theory in combination with the first-principles band structure codes allows to calculate phonons in an efficient way. In this report a formalism which enables us to apply LR theory within an all-electron framework utilizing the relativistic full-potential linearized augmented plane-wave (RFLAPW) method is presented. As first part, the equations for the calculations of the atomic forces are given and they are used for the calculation of forces in {alpha}-Pu. As a second step, a complete set of formulaes for the dynamic matrices calculation is presented.
Date: January 8, 2004
Creator: Kutepov, A L
Object Type: Report
System: The UNT Digital Library
Incorporating psychological influences in probabilistic cost analysis (open access)

Incorporating psychological influences in probabilistic cost analysis

Today's typical probabilistic cost analysis assumes an ''ideal'' project that is devoid of the human and organizational considerations that heavily influence the success and cost of real-world projects. In the real world ''Money Allocated Is Money Spent'' (MAIMS principle); cost underruns are rarely available to protect against cost overruns while task overruns are passed on to the total project cost. Realistic cost estimates therefore require a modified probabilistic cost analysis that simultaneously models the cost management strategy including budget allocation. Psychological influences such as overconfidence in assessing uncertainties and dependencies among cost elements and risks are other important considerations that are generally not addressed. It should then be no surprise that actual project costs often exceed the initial estimates and are delivered late and/or with a reduced scope. This paper presents a practical probabilistic cost analysis model that incorporates recent findings in human behavior and judgment under uncertainty, dependencies among cost elements, the MAIMS principle, and project management practices. Uncertain cost elements are elicited from experts using the direct fractile assessment method and fitted with three-parameter Weibull distributions. The full correlation matrix is specified in terms of two parameters that characterize correlations among cost elements in the same and in …
Date: January 8, 2004
Creator: Kujawski, Edouard; Alvaro, Mariana & Edwards, William
Object Type: Article
System: The UNT Digital Library
Incorporation of Chemical Reactions Into Building-scale Flow (open access)

Incorporation of Chemical Reactions Into Building-scale Flow

None
Date: January 8, 2004
Creator: Lee, R L; Humphreys, T D & Jayaweera, T M
Object Type: Article
System: The UNT Digital Library
Jet propagation through energetic materials (open access)

Jet propagation through energetic materials

In applications where jets propagate through energetic materials, they have been observed to become sufficiently perturbed to reduce their ability to effectively penetrate subsequent material. Analytical calculations of the jet Bernoulli flow provides an estimate of the onset and extent of such perturbations. Although two-dimensional calculations show the back-flow interaction pressure pulses, the symmetry dictates that the flow remains axial. In three dimensions the same pressure impulses can be asymmetrical if the jet is asymmetrical. The 3D calculations thus show parts of the jet having a significant component of radial velocity. On the average the downstream effects of this radial flow can be estimated and calculated by a 2D code by applying a symmetrical radial component to the jet at the appropriate position as the jet propagates through the energetic material. We have calculated the 3D propagation of a radio graphed TOW2 jet with measured variations in straightness and diameter. The resultant three-dimensional perturbations on the jet result in radial flow, which eventually tears apart the coherent jet flow. This calculated jet is compared with jet radiographs after passage through the energetic material for various material thickness and plate thicknesses. We noted that confinement due to a bounding metal plate …
Date: January 8, 2004
Creator: Pincosy, P & Poulsen, P
Object Type: Article
System: The UNT Digital Library
No-Core Shell Model Calculations in Light Nuclei with Three-Nucleon Forces (open access)

No-Core Shell Model Calculations in Light Nuclei with Three-Nucleon Forces

The ab initio No-Core Shell Model (NCSM) has recently been expanded to include nucleon-nucleon (NN) and three-nucleon (3N) interactions at the three-body cluster level. Here it is used to predict binding energies and spectra of p-shell nuclei based on realistic NN and 3N interactions. It is shown that 3N force (3NF) properties can be studied in these nuclear systems. First results show that interactions based on chiral perturbation theory lead to a realistic description of {sup 6}Li.
Date: January 8, 2004
Creator: Barrett, B R; Vary, J P; Nogga, A; Navratil, P & Ormand, W E
Object Type: Article
System: The UNT Digital Library
Numerical Modeling of Nonlinear Thermodynamics in SMA Wires (open access)

Numerical Modeling of Nonlinear Thermodynamics in SMA Wires

We present a mathematical model describing the thermodynamic behavior of shape memory alloy wires, as well as a computational technique to solve the resulting system of partial differential equations. The model consists of conservation equations based on a new Helmholtz free energy potential. The computational technique introduces a viscosity-based continuation method, which allows the model to handle dynamic applications where the temporally local behavior of solutions is desired. Computational experiments document that this combination of modeling and solution techniques appropriately predicts the thermally- and stress-induced martensitic phase transitions, as well as the hysteretic behavior and production of latent heat associated with such materials.
Date: January 8, 2004
Creator: Reynolds, D R & Kloucek, P
Object Type: Article
System: The UNT Digital Library
Photon and neutral pion production in Au+Au collisions at {radical}s{sub NN} = 130 GeV (open access)

Photon and neutral pion production in Au+Au collisions at {radical}s{sub NN} = 130 GeV

We report the first inclusive photon measurements about mid-rapidity (|y| < 0.5) from {sup 197}Au + {sup 197}Au collisions at {radical}s{sub NN} = 130 GeV at RHIC. Photon pair conversions were reconstructed from electron and positron tracks measured with the Time Projection Chamber (TPC) of the STAR experiment. With this method, an energy resolution of {Delta}E/E {approx} 2% at 0.5 GeV has been achieved. Reconstructed photons have also been used to measure the transverse momentum (p{sub t}) spectra of {pi}{sup 0} mesons about mid-rapidity (|y| < 1) via the {pi}{sup 0} {yields} {gamma}{gamma} decay channel. The fractional contribution of the {pi}{sup 0} {yields} {gamma}{gamma} decay to the inclusive photon spectrum decreases by 20% {+-} 5% between p{sub t} = 1.65 GeV/c and p{sub t} = 2.4 GeV/c in the most central events, indicating that relative to {pi}{sup 0} {yields} {gamma}{gamma} decay the contribution of other photon sources is substantially increasing.
Date: January 8, 2004
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type: Article
System: The UNT Digital Library
Preliminary Thoughts on Introducing Structs to SIDL/Babel: White Paper (open access)

Preliminary Thoughts on Introducing Structs to SIDL/Babel: White Paper

In the past 6 months, there has been increased interest in adding something analogous to C structs to the SIDL language and the Babel language interoperability tool [2, 6]. In particular, Rob Armstrong, of the Common Component Architecture [4], said the lack of structs ''is an oft-cited reason that people can't use Babel.'' Because the interest is high and lack of structs is a barrier to Babel adoption, we must carefully consider the current work around, the motivations for structs, the implications of adding structs, and the alternatives for structs in SIDL/Babel. This document provides the background necessary for a discussion of structs in SIDL/Babel. For the purposes of this document, I am going to call the potential new language feature a SIDL struct. The SIDL struct is analogous to a C struct, a Pascal record, or a Fortran 90 (F90) derived data type. It is a collection of data with no methods or behavior associated with it. Each element of the collection has a name and a type. SIDL structs allow for data abstraction, but they do not provide data hiding. All data is public in a SIDL struct.
Date: January 8, 2004
Creator: Epperly, T W
Object Type: Report
System: The UNT Digital Library
Probing Chiral Interactions in Light Nuclei (open access)

Probing Chiral Interactions in Light Nuclei

Chiral two- and three-nucleon interactions are studied in a few-nucleon systems. We investigate the cut-off dependence and convergence with respect to the chiral expansion. It is pointed out that the spectra of light nuclei are sensitive to the three-nucleon force structure. As an example, we present calculations of the 1{sup +} and 3{sup +} states of {sup 6}Li using the no-core shell model approach. The results show contributions of the next-to-next-to-leading order terms to the spectra, which are not correlated to the three-nucleon binding energy prediction.
Date: January 8, 2004
Creator: Nogga, A; Barrett, B R; Meissner, U; Witala, H; Epelbaum, E; Kamada, H et al.
Object Type: Article
System: The UNT Digital Library
Reversible n-Bit to n-Bit Integer Haar-Like Transforms (open access)

Reversible n-Bit to n-Bit Integer Haar-Like Transforms

None
Date: January 8, 2004
Creator: Senecal, J; Duchaineau, M & Joy, K I
Object Type: Article
System: The UNT Digital Library
Scaling up parallel scientific applications on the IBM SP (open access)

Scaling up parallel scientific applications on the IBM SP

This document provides a technical description of the IBM SP seaborg.nersc.gov with an emphasis on how the system performs as a production environment for large scale scientific applications. The overall goal is to provide developers with the information they need to write and run such applications. While some of the information presented here may be applicable in a larger context, the focus is on experiences and scaling techniques specific to seaborg.nersc.gov. In the first few sections we seek to determine how well the theoretical capabilities of this machine may be realized in practice. Most of the measured performance numbers come from small code microkernels or test codes rather than from real user codes. In a companion document several real applications are explored in detail. The microkernel approach described above has value to the user since the most widely quoted performance numbers often reflect the theoretical (peak) performance values rather than those realized in practice. Likewise anecdotes from full blown applications often involve mixed algorithms, hidden constraints or other specifics which make the results hard to generalize. Microkernels and test codes provide a middle ground which is a reasonable best case scenario for real user codes and provide the user with …
Date: January 8, 2004
Creator: Skinner, David
Object Type: Report
System: The UNT Digital Library
Shell Model in a First Principles Approach (open access)

Shell Model in a First Principles Approach

We develop and apply an ab-initio approach to nuclear structure. Starting with the NN interaction, that fits two-body scattering and bound state data, and adding a theoretical NNN potential, we evaluate nuclear properties in a no-core approach. For presently feasible no-core model spaces, we evaluate an effective Hamiltonian in a cluster approach which is guaranteed to provide exact answers for sufficiently large model spaces and/or sufficiently large clusters. A number of recent applications are surveyed including an initial application to exotic multiquark systems.
Date: January 8, 2004
Creator: Navratil, P; Nogga, A; Lloyd, R; Vary, J P; Ormand, W E & Barrett, B R
Object Type: Article
System: The UNT Digital Library
Sodium Laser Guide Star Adaptive Optics Imaging Polarimetry of Herbig Ae/Be Stars (open access)

Sodium Laser Guide Star Adaptive Optics Imaging Polarimetry of Herbig Ae/Be Stars

The future of high-resolution ground-based optical and infrared astronomy requires the successful implementation of laser guide star adaptive optics systems. We present the first science results from the Lick Observatory sodium beacon laser guide star system. By coupling this system to a near-infrared (J;H;Ks bands) dual-channel imaging polarimeter, we achieve very high sensitivity to light scattered in the circumstellar enviroment of Herbig Ae/Be stars on scales of 100-300 AU. Observations of LkH{alpha} 198 reveal a highly polarized, biconical nebula 10 arcseconds in diameter (6000 AU) . We also observe a polarized jet-like feature associated with the deeply embedded source LkH{alpha} 198-IR. The star LkH{alpha} 233 presents a narrow, unpolarized dark lane dividing its characteristic butterfly-shaped polarized reflection nebulosity. This linear structure is oriented perpendicular to an optical jet and bipolar cavity and is consistent with the presence of an optically thick circumstellar disk blocking our direct view of the star. These data suggest that the evolutionary picture developed for the lower-mass T Tauri stars is also relevant to the Herbig Ae/Be stars and demonstrate the ability of laser guide star adaptive optics systems to obtain scientific results competitive with natural guide star adaptive optics or space-based telescopes.
Date: January 8, 2004
Creator: Perrin, M D; Graham, J R; Lloyd, J P; Kalas, P; Gates, E L; Gavel, D T et al.
Object Type: Article
System: The UNT Digital Library
Three-dimensional poisson solver for a charged beam with large aspect ratio in a conducting pipe (open access)

Three-dimensional poisson solver for a charged beam with large aspect ratio in a conducting pipe

In this paper, we present a three-dimensional Poisson equation solver for the electrostatic potential of a charged beam with large longitudinal to transverse aspect ratio in a straight and a bent conducting pipe with open-end boundary conditions. In this solver, we have used a Hermite-Gaussian series to represent the longitudinal spatial dependence of the charge density and the electric potential. Using the Hermite-Gaussian approximation, the original three-dimensional Poisson equation has been reduced into a group of coupled two-dimensional partial differential equations with the coupling strength proportional to the inverse square of the longitudinal-to-transverse aspect ratio. For a large aspect ratio, the coupling is weak. These two-dimensional partial differential equations can be solved independently using an iterative approach. The iterations converge quickly due to the large aspect ration of the beam. For a transverse round conducting pipe, the two-dimensional Poisson equation is solved using a Bessel function approximation and a Fourier function approximation. The three-dimensional Poisson solver can have important applications in the study of the space-charge effects in the high intensity proton storage ring accelerator or induction linear accelerator for heavy ion fusion where the ration of bunch length to the transverse size is large.
Date: January 8, 2004
Creator: Qiang, Ji & Gluckstern, Robert L.
Object Type: Article
System: The UNT Digital Library
Active Cathodes for Super-High Power Density Solid Oxide Fuel Cells Through Space Charge Effects Quarterly Report: October-December 2003 (open access)

Active Cathodes for Super-High Power Density Solid Oxide Fuel Cells Through Space Charge Effects Quarterly Report: October-December 2003

This report summarizes the work done during the fifth quarter of the project. Effort was directed in two areas: (1) Further development of the model on the role of connectivity on ionic conductivity of porous bodies, including the role of grain boundaries and space charge region. (2) Fabrication of porous samaria-doped ceria (SDC) and investigation of the effect of thermal treatment on its conductivity. The model developed accounts for transport through three regions: (a) Transport through the bulk of the grain, RI, which includes parallel transport through space charge region. (b) Transport through the space charge region adjacent to the neck (grain boundary), RII. (c) Transport through the structural part of the neck (grain boundary), RIII. The work on the model development involves calculation RI, RII, RIII, and the sum of these three terms, which is the total resistance, as a function of the grain radius ranging between 0.5 and 5 microns and as a function of the relative neck size, described in terms of the angle theta, ranging between 5 and 45{sup o}. Three values of resistivity of the space charge region were chosen; space charge resistivity greater than grain resistivity, equal to grain resistivity, and lower than grain …
Date: March 8, 2004
Creator: Virkar, Anil V.
Object Type: Report
System: The UNT Digital Library
Argonne National Laboratory-East summary site environmental report for calendar year 2002. (open access)

Argonne National Laboratory-East summary site environmental report for calendar year 2002.

Argonne performs research and development in many areas of science and technology. General fields of research at Argonne include, but are not limited to, biosciences, biotechnology, chemical engineering, chemistry, decision and information sciences, energy systems and technology, high energy physics, materials science, math and computer science, nuclear reactors, physics, and environmental science. Argonne is not, and never has been, a weapons laboratory. Several missions provide focus for Argonne scientists. Basic research helps better understand the world, and applied research helps protect and improve it. For example, the prairies of Argonne provide sites for environmental studies that provide valuable information about invader species and the food webs within ecosystems. Argonne also operates world-class research facilities, such as the Advanced Photon Source (APS), which is a national research facility funded by the U.S. Department of Energy (DOE). Scientists use high brilliance X-rays from the APS for basic and applied research in many fields. Argonne also seeks to ensure our energy future. Currently, scientists and engineers are developing cleaner and more efficient energy sources, such as fuel cells and advanced electric power generation. Argonne has spent much of its history on developing nuclear reactor technology. That research is now being applied to American …
Date: March 8, 2004
Creator: Golchert, N. W. & Kolzow, R. G.
Object Type: Report
System: The UNT Digital Library
Development of a Real-Time Radiological Area Monitoring Network for Emergency Response at Lawrence Livermore National Laboratory (open access)

Development of a Real-Time Radiological Area Monitoring Network for Emergency Response at Lawrence Livermore National Laboratory

A real-time radiological sensor network for emergency response was developed and deployed at the Lawrence Livermore National Laboratory (LLNL). The Real-Time Radiological Area Monitoring (RTRAM) network is comprised of 16 Geiger-Mueller (GM) sensors positioned on the LLNL Livermore site perimeter to continuously monitor for a radiological condition resulting from a terrorist threat to site security and the health and safety of LLNL personnel. The RTRAM network sensor locations coincide with wind sector directions to provide thorough coverage of the one square mile site. These low-power sensors are supported by a central command center (CCC) and transmit measurement data back to the CCC computer through the LLNL telecommunications infrastructure. Alarm conditions are identified by comparing current data to predetermined threshold parameters and are validated by comparison with plausible dispersion modeling scenarios and prevailing meteorological conditions. Emergency response personnel are notified of alarm conditions by automatic radio and computer based notifications. A secure intranet provides emergency response personnel with current condition assessment data that enable them to direct field response efforts remotely. The RTRAM network has proven to be a reliable system since initial deployment in August 2001 and maintains stability during inclement weather conditions.
Date: March 8, 2004
Creator: Bertoldo, N; Hunter, S; Fertig, R; Laguna, G & MacQueen, D
Object Type: Article
System: The UNT Digital Library
GENII Version 2 Software Design Document (open access)

GENII Version 2 Software Design Document

This document describes the architectural design for the GENII-V2 software package. This document defines details of the overall structure of the software, the major software components, their data file interfaces, and specific mathematical models to be used. The design represents a translation of the requirements into a description of the software structure, software components, interfaces, and necessary data. The design focuses on the major components and data communication links that are key to the implementation of the software within the operating framework. The purpose of the GENII-V2 software package is to provide the capability to perform dose and risk assessments of environmental releases of radionuclides. The software also has the capability of calculating environmental accumulation and radiation doses from surface water, groundwater, and soil (buried waste) media when an input concentration of radionuclide in these media is provided. This report represents a detailed description of the capabilities of the software product with exact specifications of mathematical models that form the basis for the software implementation and testing efforts. This report also presents a detailed description of the overall structure of the software package, details of main components (implemented in the current phase of work), details of data communication files, and …
Date: March 8, 2004
Creator: Napier, Bruce A.; Strenge, Dennis L.; Ramsdell, James V.; Eslinger, Paul W. & Fosmire, Christian J.
Object Type: Report
System: The UNT Digital Library
Modeling Soil Quality Thresholds to Ecosystem Recovery at Fort Benning, Georgia, USA (open access)

Modeling Soil Quality Thresholds to Ecosystem Recovery at Fort Benning, Georgia, USA

The objective of this research was to use a simple model of soil C and N dynamics to predict nutrient thresholds to ecosystem recovery on degraded soils at Fort Benning, Georgia, in the southeastern USA. The model calculates aboveground and belowground biomass, soil C inputs and dynamics, soil N stocks and availability, and plant N requirements. A threshold is crossed when predicted soil N supplies fall short of predicted N required to sustain biomass accrual at a specified recovery rate. Four factors were important to development of thresholds to recovery: (1) initial amounts of aboveground biomass, (2) initial soil C stocks (i.e., soil quality), (3) relative recovery rates of biomass, and (4) soil sand content. Thresholds to ecosystem recovery predicted by the model should not be interpreted independent of a specified recovery rate. Initial soil C stocks influenced the predicted patterns of recovery by both old field and forest ecosystems. Forests and old fields on soils with varying sand content had different predicted thresholds to recovery. Soil C stocks at barren sites on Fort Benning generally lie below predicted thresholds to 100% recovery of desired future ecosystem conditions defined on the basis of aboveground biomass (18000 versus 360 g m{sup …
Date: March 8, 2004
Creator: Garten C.T. Jr.
Object Type: Report
System: The UNT Digital Library
Operation of Ferroelectric Plasma Sources in a Gas Discharge Mode (open access)

Operation of Ferroelectric Plasma Sources in a Gas Discharge Mode

Ferroelectric plasma sources in vacuum are known as sources of ablative plasma, formed due to surface discharge. In this paper, observations of a gas discharge mode of operation of the ferroelectric plasma sources (FPS) are reported. The gas discharge appears at pressures between approximately 20 and approximately 80 Torr. At pressures of 1-20 Torr, there is a transition from vacuum surface discharge to the gas discharge, when both modes coexist and the surface discharges sustain the gas discharge. At pressures between 20 and 80 Torr, the surface discharges are suppressed, and FPS operate in pure gas discharge mode, with the formation of almost uniform plasma along the entire surface of the ceramics between strips. The density of the expanding plasma is estimated to be about 1013 cm-3 at a distance of 5.5 mm from the surface. The power consumption of the discharge is comparatively low, making it useful for various applications. This paper also presents direct measurements of the yield of secondary electron emission from ferroelectric ceramics, which, at low energies of primary electrons, is high and dependent on the polarization of the ferroelectric material
Date: March 8, 2004
Creator: Dunaevsky, A. & Fisch, N. J.
Object Type: Report
System: The UNT Digital Library
Quantifying Stratospheric Ozone in the Upper Troposphere Using in situ Measurements of HCl (open access)

Quantifying Stratospheric Ozone in the Upper Troposphere Using in situ Measurements of HCl

A chemical ionization mass spectrometry (CIMS) technique has been developed for precise in situ measurements of hydrochloric acid (HCl) from a high-altitude aircraft. In measurements at subtropical latitudes, minimum HCl values found in the upper troposphere (UT) are often near or below the 0.005-ppbv detection limit of the measurements, indicating that background HCl values are much lower than a global mean estimate. However, significant abundances of HCl were observed in many UT air parcels as a result of stratosphere-to-troposphere transport events. A method for diagnosing the amount of stratospheric ozone in these UT parcels was developed using the compact linear correlation of HCl with ozone found throughout the lower stratosphere (LS). Expanded use of this method will lead to improved quantification of cross-tropopause transport events and validation of global chemical transport models.
Date: March 8, 2004
Creator: Atherton, C. S.; Bergmann, D. J.; Marcy, T. P.; Fahey, D. W.; Gao, R. S.; Popp, P. J. et al.
Object Type: Article
System: The UNT Digital Library
Review of Corrosion Inhibition in High Level Radioactive Waste Tanks in the DOE Complex (open access)

Review of Corrosion Inhibition in High Level Radioactive Waste Tanks in the DOE Complex

Radioactive waste is stored in underground storage tanks at the Department of Energy (DOE) Savannah River Site (SRS). The waste tanks store supernatant liquid salts, consisting primarily of sodium nitrate, sodium nitrite, sodium hydroxide, and sludge. An assessment of the potential degradation mechanisms of the high level waste (HLW) tanks determined that nitrate- induced pitting corrosion and stress corrosion cracking were the two most significant degradation mechanisms. Controls on the solution chemistry (minimum nitrite and hydroxide concentrations) are in place to prevent the initiation and propagation of pitting and stress corrosion cracking in the tanks. These controls are based upon a series of experiments performed using simulated solutions on materials used for construction of the tanks. The technical bases and evolution of these controls is presented.
Date: March 8, 2004
Creator: Subramanian, K.H.
Object Type: Article
System: The UNT Digital Library
RPP-WTP LAW Melter Offgas Flammability Assessment (open access)

RPP-WTP LAW Melter Offgas Flammability Assessment

The objective of this work was to develop predictive models for the Low Activity Waste (LAW) melter offgas flammability assessment and to conduct case studies in support of the on-going safety analysis efforts for the River Protection Project Waste Treatment Plant (RPPWTP). This required that Savannah River Technology Center (SRTC) personnel develop process models that are comprehensive enough to explicitly describe the effects of key melter operating variables such as total organic carbon (TOC) in the feed, melter air purge, and vapor space temperature on the offgas flammability.
Date: March 8, 2004
Creator: Choi, AS
Object Type: Report
System: The UNT Digital Library