A flexible, robust method for linking grids of locally refined models constructed with different numerical methods is needed to address a variety of hydrologic problems. This work outlines and tests a new ghost-node model-linking method for a refined ''child'' model that is contained within a larger and coarser ''parent'' model that is based on the iterative method of Mehl and Hill (2002, 2004). The method is applicable to steady-state solutions for ground-water flow. Tests are presented for a homogeneous two-dimensional system that has either matching grids (parent cells border an integer number of child cells; Figure 2a) or non-matching grids (parent cells border a non-integer number of child cells; Figure 2b). The coupled grids are simulated using the finite-difference and finite-element models MODFLOW and FEHM, respectively. The simulations require no alteration of the MODFLOW or FEHM models and are executed using a batch file on Windows operating systems. Results indicate that when the grids are matched spatially so that nodes and child cell boundaries are aligned, the new coupling technique has error nearly equal to that when coupling two MODFLOW models (Mehl and Hill, 2002). When the grids are non-matching, model accuracy is slightly increased over matching-grid cases. Overall, results …

The detection of the unconventional delivery of a nuclear weapon or the illicit transport of fissile materials is one of the most crucial, and difficult, challenges facing us today in national security. A wide array of radiation detectors are now being deployed domestically and internationally to address this problem. This initial deployment will be followed by radiation detection systems, composed of intelligent, networked devices intended to supplement the choke-point perimeter systems with more comprehensive broad-area, or regional coverage. Cataloging and fusing the data from these new detection systems will clearly be one of the most significant challenges in radiation-based security systems. We present here our results from our first 6 months of effort on this project. We anticipate the work will continue as part of the Predictive Knowledge System Strategic Initiative.

This letter forwards a compilation of knowledge gained regarding international interactions and issues associated with Project Prometheus. The following topics are discussed herein: (1) Assessment of international fast reactor capability and availability; (2) Japanese fast reactor (JOYO) contracting strategy; (3) NRPCT/Program Office international contract follow; (4) Completion of the Japan Atomic Energy Agency (JAEA)/Pacific Northwest National Laboratory (PNNL) contract for manufacture of reactor test components; (5) US/Japanese Departmental interactions and required Treaties and Agreements; and (6) Non-technical details--interactions and considerations.

Recent studies conducted for the Hanford Waste Treatment Plant (WTP) found that the centrifuged solids from tanks 241-AW-101, 241-AN-107, and 241-C-104 contained two carcinogenic chemicals, 1-naphthylamine and 2,2-bis(4-chlorophenyl)-1,1-dichloroethene (DDE), that had never been detected in tank headspaces. This report estimates the potential headspace concentrations associated with these two compounds. The calculation was based on a comparison of headspace concentrations and waste concentrations for sixteen other organic compounds in the passively-ventilated tank 241-C-104. An approximate relation was found between the compounds? solubilities in water and their headspace concentrations. The relation was used to estimate the 241-C-104 headspace concentration that would result from the maximum measured waste concentrations of DDE and 1-naphthylamine. On the basis of the assumptions made in this report about organic compound transport and equilibration, the DDE concentration was estimated at well below one part per trillion, below standard analytical detection limits. However, 1-naphthylamine could potentially be present in the headspace of a passively ventilated tank at the 30 ppb level.

Ferrocene-based molecular components for nanoelectronics offer a number of distinct advantages relative to all carbon frameworks due to metal-centered molecular states that should be closer in energy to the Fermi levels of the metal electrodes in metal / molecule / metal heterojunctions. Given this, the overall goal of the project was to investigate the conduction physics of a variety of proposed ferrocene diode / transistor designs in order to address the fundamental question; can electron transport within nm-length scale structures be modulated in a controlled fashion? During the funded period, substantial progress towards achieving this goal was made by surmounting a number of scientific and technical obstacles. More specifically, a concise and general synthetic route to several mono- and diferrocene dithiols and monothiols was achieved that now allows for the directed and controlled assembly of a variety of metal / molecule /metal test structures for the single molecule conductance measurements and the fabrication of self-assembled monolayers (SAMs) on Au(111) that are amenable to quantitative electrochemical characterization of electron-transfer rates. Most importantly, by using an electromigrated test structure, reproducible I/V data for one of the ferrocene dithiol molecules have been collected which exhibit surprisingly high conductance. Exceptional agreement of this result …

SRNL received funding in FY 2005 to test the Hybrid Sulfur (HyS) Process for generating hydrogen. This technology employs an electrolyzer that uses a sulfur dioxide depolarized anode to greatly reduce the electrical energy requirement. The required current is the same as for conventional electrolysis of water, but the required cell voltage is reduced. The electrolyzer is a key part of HyS technology. Completing the material loop for HyS requires a high temperature decomposition of sulfuric acid to regenerate the sulfur dioxide gas needed for the anode reaction. Oxygen is also produced and could be sold. The decomposition of sulfuric acid is being studied by others in a separately funded task. It is not included in this SRNL task.

The University Research Program in Robotics (URPR) Implementation Plan is an integrated group of universities performing fundamental research that addresses broad-based robotics and automation needs of the NNSA Directed Stockpile Work (DSW) and Campaigns. The URPR mission is to provide improved capabilities of robotics science and engineering to meet the future needs of all weapon systems and other associated NNSA/DOE activities.

We have released Version 2 of Milagro, an object-oriented, C++ code that performs radiative transfer using Fleck and Cummings' Implicit Monte Carlo method. Milagro, a part of the Jayenne program, is a stand-alone driver code used as a methods research vehicle and to verify its underlying classes. These underlying classes are used to construct Implicit Monte Carlo packages for external customers. Milagro-2 represents a design overhaul that allows better parallelism and extensibility. New features in Milagro-2 include verified momentum deposition, restart capability, graphics capability, exact energy conservation, and improved load balancing and parallel efficiency. A users' guide also describes how to configure, make, and run Milagro2.

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