The simultaneous diffusion of Si and the dopants B, P, and As has been studied by the use of a multilayer structure of isotopically enriched Si. This structure, consisting of 5 pairs of 120 nm thick natural Si and {sup 28}Si enriched layers, enables the observation of {sup 30}Si self-diffusion from the natural layers into the {sup 28}Si enriched layers, as well as dopant diffusion from an implanted source in an amorphous Si cap layer, via Secondary Ion Mass Spectrometry (SIMS). The dopant diffusion created regions of the multilayer structure that were extrinsic at the diffusion temperatures. In these regions, the Fermi level shift due to the extrinsic condition altered the concentration and charge state of the native defects involved in the diffusion process, which affected the dopant and self-diffusion. The simultaneously recorded diffusion profiles enabled the modeling of the coupled dopant and self-diffusion. From the modeling of the simultaneous diffusion, the dopant diffusion mechanisms, the native defect charge states, and the self- and dopant diffusion coefficients can be determined. This information is necessary to enhance the physical modeling of dopant diffusion in Si. It is of particular interest to the modeling of future electronic Si devices, where the nanometer-scale …

FLIRE was designed to measure the hydrogen and helium retention and diffusivity in a flowing stream of liquid lithium, and it has accomplished these goals. Retention coefficients for helium in the flowing liquid stream were 0.1-2% for flow speeds of 44 cm/s and implantation energies between 500 and 2000 eV. The energy dependence of retention is linear for the energy range considered, as expected, and the dependence of retention on flow velocity fits the expected square-root of flow speed dependence. Estimates of the helium diffusion coefficient in the flowing lithium stream were {approx} 4 x 10{sup -7} cm{sup 2}/s, and are independent of implantation energy. This value is much lower than expected, which could be due to several factors, such as mixing, bubble formation or surface film formation. In the case of hydrogen, long term retention and release mechanisms are of greatest importance, since this relates to tritium inventory in flowing lithium PFCs for fusion applications. The amount of hydride formation was measured for flowing lithium exposed to neutral deuterium gas. Thermal desorption spectroscopy (TDS) measurements indicate that the hydride concentration was between 0.1 and 0.2% over a wide range of pressures (6.5 x 10{sup -5} to 1 Torr). This …

In modeling complex environmental problems, we often fail to make precise statements about inputs and outcome. In this case the fuzzy logic method native to the human mind provides a useful way to get at these problems. Fuzzy logic represents a significant change in both the approach to and outcome of environmental evaluations. Risk assessment is currently based on the implicit premise that probability theory provides the necessary and sufficient tools for dealing with uncertainty and variability. The key advantage of fuzzy methods is the way they reflect the human mind in its remarkable ability to store and process information which is consistently imprecise, uncertain, and resistant to classification. Our case study illustrates the ability of fuzzy logic to integrate statistical measurements with imprecise health goals. But we submit that fuzzy logic and probability theory are complementary and not competitive. In the world of soft computing, fuzzy logic has been widely used and has often been the ''smart'' behind smart machines. But it will require more effort and case studies to establish its niche in risk assessment or other types of impact assessment. Although we often hear complaints about ''bright lines,'' could we adapt to a system that relaxes these …

Urban population density can influence transportation demand, as expressed through average daily vehicle-kilometers traveled per capita (VKT). In turn, changes in transportation demand influence total passenger vehicle emissions. Population density can also influence the fraction of total emissions that are inhaled by the exposed urban population. Equations are presented that describe these relationships for an idealized representation of an urban area. Using analytic solutions to these equations, we investigate the effect of three changes in urban population and urban land area (infill, sprawl, and constant-density growth) on per capita inhalation intake of primary pollutants from passenger vehicles. The magnitude of these effects depends on density-emissions elasticity ({var_epsilon}{sub e}), a normalized derivative relating change in population density to change in vehicle emissions. For example, if urban population increases, per capita intake is less with infill development than with constant-density growth if {var_epsilon}{sub e} is less than -0.5, while for {var_epsilon}{sub e} greater than -0.5 the reverse is true.

Production of 18 superconducting low-beta quadrupoles (MQXB) for the LHC is well advanced. These 5.5 m long magnets are designed to operate at 1.9 K with a peak field gradient of 215 T/m in 70 mm aperture. Two MQXB cold masses with a dipole orbit corrector between them form a single cryogenic unit (LQXB) which is the Q2 optical element of the final focus triplets in the LHC interaction regions. A program of magnetic field quality and alignment measurements of the cold masses is performed at room temperature during magnet fabrication and of the LQXB assembly as well as at superfluid helium temperature. Results of these measurements are summarized in this paper.

This paper informally speculates on the challenges of determining the atomic-scale surface and interface structure of nanomaterials. The relative capabilities of different techniques are compared. This includes discussion of theoretical methods needed to interpret experimental techniques.

To comply with the applicable requirements of the U.S. Department of Energy (US DOE), this closure plan has been developed for the E-Area Low-Level Waste Facility(LLWF). The plan is organized according to the specifications of the Format and Content Guide for U.S. Department of Energy Low-Level Waste Disposal Facility Closure Plans. Section 2 provides a brief overview of the general facility description, closure approach, closure schedule, related activities, and key assumptions. Sections 3 and 4 provide specific details of facility characteristics and the technical approach to closure, respectively, as well as supporting information. Additional schedule details are provided in Section 5. Section 6 provides a list of recommended items for consideration in association with future revisions to the E-Area LLWF Closure Plan and Performance Assessment (PA). Operation of the E-Area LLWF began with placement of the first low-level waste box within the Low Activity Waste (LAW) Vault. It is anticipated that operations will continue for at least 25 years, and that a 100-year institutional control period will follow cessation of operations. It is further anticipated that closure will be conducted in the following three phases: operational closure, interim closure, and final closure. Operational closure will be conducted during the 25 …

Department of Energy (DOE) facilities within the weapons complex face a daunting challenge of remediating huge below inventories of legacy radioactive and toxic metal waste. More often than not, the scope of the problem is massive, particularly in the high recharge, humid regions east of the Mississippi river, where the off-site migration of contaminants continues to plague soil water, groundwater, and surface water sources. As of 2002, contaminated sites are closing rapidly and many remediation strategies have chosen to leave contaminants in-place. In situ barriers, surface caps, and bioremediation are often the remedial strategies of chose. By choosing to leave contaminants in-place, we must accept the fact that the contaminants will continue to interact with subsurface and surface media. Contaminant interactions with the geosphere are complex and investigating long term changes and interactive processes is imperative to verifying risks. We must be able to understand the consequences of our action or inaction. The focus of this manuscript is to describe recent technical developments for assessing the performance of in situ bioremediation and immobilization of subsurface metals and radionuclides. Research within DOE's NABIR and EMSP programs has been investigating the possibility of using subsurface microorganisms to convert redox sensitive toxic metals …

Although it is well known that the rate of sintering is governed by deceleratory kinetics, it is often difficult to fit power-law and nth-order reaction models over broad time-temperature ranges. This work shows that a phenomenological model combining a reaction order with an activation energy distribution can correlate surface area as a function of sintering time and temperature over a greater range of those variables. Qualitatively, the activation energy distribution accounts the dependence of free energy on particle size and material defects, while the reaction order accounts for geometric factors such as a distribution of diffusion lengths. The model is demonstrated for sintering of hydroxyapatite using data of Bailliez and Nzihou (Chem. Eng. J. 98 (2004), 141-152).

The objective of this research is to widen the application of foam to enhanced oil recovery (EOR) by investigating fundamental mechanisms of foams in porous media. This research will lay the groundwork for more applied research on foams for improved sweep efficiency in miscible gas, steam and surfactant-based EOR. Task 1 investigates the pore-scale interactions between foam bubbles and polymer molecules. Task 2 examines the mechanisms of gas trapping, and interaction between gas trapping and foam effectiveness. Task 3 investigates mechanisms of foam generation in porous media. Significant progress was made during this period on all three Tasks. Regarding Task 1, we continued comparisons of foam behavior in sandpacks with and without polymer and oil. As in our previous results, decane was moderately destabilizing to foam. Xanthan polymer did not stabilize foam in the presence of decane in this case. Rather, it appears to have destabilized foam, so that pressure gradient decreased in spite of the increase in aqueous-phase viscosity. Research on Task 2 included the first shake-down experiments with our new apparatus for gas-phase tracer tests for direct measurement of trapped-gas saturation with foam. In addition, we began to analyze CT images of gas-phase tracer in foam displacements, which …

Although materials that exhibit nearest-neighbor-only antiferromagnetic interactions and geometrical frustration theoretically should not magnetically order in the absence of disorder, few such systems have been observed experimentally. One such system appears to be the pyrochlore Tb{sub 2}Ti{sub 2}O{sub 7}. However, previous structural studies indicated that Tb{sub 2}Ti{sub 2}O{sub 7} is an imperfect pyrochlore. To clarify the situation, we performed neutron powder diffraction (NPD) and x-ray absorption fine structure (XAFS) measurements on samples that were prepared identically to those that show no magnetic order. The NPD measurements show that the long-range structure of Tb{sub 2}Ti{sub 2}O{sub 7} is well ordered with no structural transitions between 4.5 and 600 K. In particular, mean-squared displacements (u{sup 2}'s) for each site follow a Debye model with no offsets. No evidence for Tb/Ti site interchange was observed within an upper limit of 2%. Likewise, no excess or deficiency in the oxygen stoichiometry was observed, within an upper limit of 2% of the nominal pyrochlore value. Tb L{sub III} and Ti K-edge XAFS measurements from 20-300 K similarly indicate a well-ordered local structure. Other aspects of the structure are considered. We conclude that Tb{sub 2}Ti{sub 2}O{sub 7} has, within experimental error, an ideal, disorder-free pyrochlore lattice, …

Summary of activity related to development of the Alliance of Clean Energy Business Incubators and incubation services provided to the clean energy sector by the Advanced Technology Development Center at the Georgia Institute of Technology.

Algebraic sub-structuring refers to the process of applying matrix reordering and partitioning algorithms to divide a large sparse matrix into smaller submatrices from which a subset of spectral components are extracted and combined to form approximate solutions to the original problem. In this paper, we show that algebraic sub-structuring can be effectively used to solve generalized eigenvalue problems arising from the finite element analysis of an accelerator structure.

This report addresses a quarterly report about the advanced technologies of stripper gas well enhancement from July 1 to September 30, 2003

In this report, the major results and conclusions of the research over the last two years and five months is considered. The report discusses the mechanistic aspects of oxygen quenching of solid-matrix phosphorescence (SMP), mechanistic aspects of moisture quenching of SMP, interactions and methodology to investigate phosphors in glucose glasses, new methods for coating filter paper for solid-phase microextraction with solid-matrix fluorescence (SMF) and SMP detection, mechanistic consideration of the heavy-atom quenching of the SMF and the enhancement of SMP of benzo[a]pyrene-DNA adducts, and new developments in liquid-liquid-liquid microextraction.

Irradiation of materials by energetic particles (e.g. electrons, ions and neutrons) is associated with very high internal power dissipation, which can drive the underlying nano- and microstructure far from normal equilibrium conditions. One of the most unusual responses in this connection is the ability of the material's nano- and microstructure to self-assemble in well-organized, two- and three-dimensional periodic arrangements. We reviewed and assessed experimental evidence and theoretical models pertaining to the physical understanding of nano- and microstructure self-organization under irradiation conditions. Experimental observations on the formation of self-organized defect clusters, dislocation loops, voids and bubbles were presented and critically assessed. Implantation of metals with energetic helium results in remarkable self-assembled bubble super-lattices with wavelengths (super-lattice parameters) in the range of 5-8 nm. Ion and neutron irradiation produce a wide variety of self-assembled 3-D defect walls and void lattices, with wavelengths that can be tailored in the range of 10's to 100's of nanometers. Theoretical models aimed at explaining these observations were introduced, and a consistent description of many features is outlined. The primary focus of the most recent modeling efforts, which are based on stability theory and concepts of non-linear dynamics, was to determine criteria for the evolution and spatial …

Python is a flexible, powerful, high-level language with excellent interactive and introspective capabilities and a very clean syntax. As such, it can be a very effective tool for driving physics analysis. Python is designed to be extensible in low-level C-like languages, and its use as a scientific steering language has become quite widespread. To this end, existing and custom-written C or C++ libraries are bound to the Python environment as so-called extension modules. A number of tools for easing the process of creating such bindings exist, such as SWIG and Boost. Python. Yet, the process still requires a considerable amount of effort and expertise. The C++ language has few built-in introspective capabilities, but tools such as LCGDict and CINT add this by providing so-called dictionaries: libraries that contain information about the names, entry points, argument types, etc. of other libraries. The reflection information from these dictionaries can be used for the creation of bindings and so the process can be fully automated, as dictionaries are already provided for many end-user libraries for other purposes, such as object persistency. PyLCGDict is a Python extension module that uses LCG dictionaries, as PyROOT uses CINT reflection information, to allow /cwPython users to access …

The knowledge of how to ventilate buildings, and how much ventilation is necessary for human health and comfort, has evolved over centuries of trial and error. Humans and animals have developed successful solutions to the problems of regulating temperature and removing air pollutants through the use of ventilation. These solutions include ingenious construction methods, such as engineered passive ventilation (termite mounds and passive stacks), mechanical means (wing-powered, fans), and an evolving effort to identify problems and develop solutions. Ventilation can do more than help prevent building occupants from getting sick; it can provide an improved indoor environment. Codes and standards provide minimum legal requirements for ventilation, but the need for ventilation goes beyond code minima. In this paper we will look at indoor air pollutant sources over time, the evolution of ventilation strategies, current residential ventilation codes and standards (e.g., recently approved ASHRAE Standard 62.2), and briefly discuss ways in which we can go beyond the standards to optimize residential ventilation, reduce indoor air quality problems, and provide corresponding social and economic benefit.

The Genomics Annotation Platform (GAP) was designed to develop new tools for high throughput functional annotation and characterization of protein sequences and structures resulting from genomics and structural proteomics, benchmarking and application of those tools. Furthermore, this platform integrated the genomic scale sequence and structural analysis and prediction tools with the advanced structure prediction and bioinformatics environment of ICM. The development of GAP was primarily oriented towards the annotation of new biomolecular structures using both structural and sequence data. Even though the amount of protein X-ray crystal data is growing exponentially, the volume of sequence data is growing even more rapidly. This trend was exploited by leveraging the wealth of sequence data to provide functional annotation for protein structures. The additional information provided by GAP is expected to assist the majority of the commercial users of ICM, who are involved in drug discovery, in identifying promising drug targets as well in devising strategies for the rational design of therapeutics directed at the protein of interest. The GAP also provided valuable tools for biochemistry education, and structural genomics centers. In addition, GAP incorporates many novel prediction and analysis methods not available in other molecular modeling packages. This development led to signing …

For representing the source-term of a proposed repository at Yucca Mountain, NV, total system performance assessment models evaluate the disequilibrium degradation of the waste forms to capture a bounding rate for radionuclide source-term availability and use solubility constraints that are more representative of longer-term, equilibrium processes to limit radionuclide mass transport from the source-term. These solubility limits capture precipitation processes occurring either as the waste forms alter, or in the near-field environment as chemical conditions evolve. A number of alternative models for solubility controls on dissolved neptunium concentrations have been evaluated. These include idealized models based on precipitation of neptunium as separate oxide minerals and more complex considerations of trace amounts of neptunium being incorporated into the secondary uranyl phases from waste form alteration. Thermodynamic models for neptunium under oxidizing conditions indicate that tetravalent neptunium (NpO{sub 2}) solids are more stable relative to pentavalent (Np{sub 2}O{sub 5}) phases, and thereby set lower dissolved concentrations of neptunyl species. Data on solids and solutions from slow flow through (dripping) tests on spent fuel grains indicate that neptunium is tetravalent in the spent fuel and that over {approx}9 years the neptunium concentrations are near to or below calculated NpO{sub 2} solubility. The possibility …

This project has two major tasks: Task 1. The construction of a new air/helium facility to collect detailed measurements of Rayleigh-Taylor (RT) mixing at high Atwood number, and the distribution of these data to LLNL, LANL, and Alliance members for code validation and design purposes. Task 2. The collection of initial condition data from the new Air/Helium facility, for use with validation of RT simulation codes at LLNL and LANL. Also, studies of multi-layer mixing with the existing water channel facility. Over the last twelve (12) months there has been excellent progress, detailed in this report, with both tasks. As of December 10, 2004, the air/helium facility is now complete and extensive testing and validation of diagnostics has been performed. Currently experiments with air/helium up to Atwood numbers of 0.25 (the maximum is 0.75, but the highest Reynolds numbers are at 0.25) are being performed. The progress matches the project plan, as does the budget, and we expect this to continue for 2005. With interest expressed from LLNL we have continued with initial condition studies using the water channel. This work has also progressed well, with one of the graduate Research Assistants (Mr. Nick Mueschke) visiting LLNL the past two …

This paper presents the basics of this model, including what physical conditions could produce a calibration constant shift and what might cause those conditions to arise. The new evidences are discussed and it is shown that the possibility of at-the-electrode recombination cannot be eliminated, in fact prior photographic evidence is shown to be reasonable evidence of this phenomenon. Thus in the absence of definitive data, the conclusion that apparent excess heat arises from a nuclear cause is premature. If the apparent excess heat signal is not representative of a true heat source, but is instead an equipment/method malfunction, integrating the signal is of no value. This paper proposes that is the situation, and will therefore focus on examining the phenomenon of apparent excess enthalpy (sometimes called excess heat). Not addressed will be the myriad of other purported evidences of nuclear reactions. The apparent excess heat claims form the largest block of claims for a nuclear FPHE cause, and the correlation of apparent excess heat with apparent nuclear ash detection is often cited as evidence of the nuclear nature of the FPHE. But confidence in the validity of the apparent excess heat signal is of critical importance in validating a nuclear …

SRTC personnel are developing a technique that can determine the concentration of tetraphenylborate (TPB) at 300 grams in 100,000 gallons of salt solution (0.8 mg/L) in the presence of0.378 Ci/gal of Cs-137. The current High Performance Liquid Chromatography (HPLC) method of analysis can determine the TPB concentration at 5 mg/L and higher. The limit of quantitation was lowered by modification of the sample preparation steps. The HPLC sample preparation method currently used requires neutralization of the tank waste sample followed by extraction with acetonitrile. This method dilutes the tank waste sample 6.5 to 1 increasing the limit of quantitation. The method described in this report concentrates the sample two-fold lowering the limit of quantitation from 5 mg/L to 0.25mg/L. Researchers used solvent extraction of undiluted tank waste to isolate, and concentrate (two-fold) samples of tank supernate and Plant Inhibited Water (PIW) that simulated tank supernate at the cesium level of approximately 0.3 Ci/gal. The 137Cs content in the tank supernate measured 0.65 Ci/gal prior to a two-fold dilution with PIW. The concentration of the TPB was determined by HPLC on a reversed-phase HPLC column using methanol, acetonitrile, and buffered water as the mobile phase. Important Findings: The 0.8 mg/L quantitation …

The 9975 shipping package incorporates a cane fiberboard overpack for thermal insulation and impact resistance. Mechanical properties (tensile and compressive behavior) have been measured on cane fiberboard and a similar wood-based product following short-term conditioning in several temperature/humidity environments. Both products show similar trends, and vary in behavior with material orientation, temperature and humidity. A memory effect is also seen in that original strength values are only partially recovered following exposure to a degrading environment and return to ambient conditions.