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Calculations of collisional thermal and particle diffusivities in toroidal magnetic plasma confinement devices order the toroidal gyroradius to be small relative to the poloidal gyroradius. This ordering is central to what is usually referred to as neoclassical transport theory. This ordering is incorrect at low aspect ratio, where it can often be the case that the toroidal gyroradius is larger than the poloidal gyroradius. We calculate the correction to the particle and thermal diffusivities at low aspect ratio by comparing the diffusivities as determined by a full orbit code (which we refer to as omni-classical diffusion) with those from a gyroaveraged orbit code (neoclassical diffusion). In typical low aspect ratio devices the omni-classical diffusion can be up to 2.5 times the calculated neoclassical value. We discuss the implications of this work on the analysis of collisional transport in low aspect ratio magnetic confinement experiments.

This is the thirteenth Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT41047. The goal of the project is to develop and demonstrate a Virtual Engineering-based framework for simulating the performance of Advanced Power Systems. Within the last quarter, good progress has been made on all aspects of the project. Software development efforts have focused on a preliminary detailed software design for the enhanced framework. Given the complexity of the individual software tools from each team (i.e., Reaction Engineering International, Carnegie Mellon University, Iowa State University), a robust, extensible design is required for the success of the project. In addition to achieving a preliminary software design, significant progress has been made on several development tasks for the program. These include: (1) the enhancement of the controller user interface to support detachment from the Computational Engine and support for multiple computer platforms, (2) modification of the Iowa State University interface-to-kernel communication mechanisms to meet the requirements of the new software design, (3) decoupling of the Carnegie Mellon University computational models from their parent IECM (Integrated Environmental Control Model) user interface for integration with the new framework and (4) development of a new CORBA-based model interfacing specification. A benchmarking exercise to compare …

Understanding magnetospheric dynamics and predicting future behavior of the magnetosphere is of great practical interest because it could potentially help to avert catastrophic loss of power and communications. In order to build good predictive models it is necessary to understand the most critical nonlinear dependencies among observed plasma and electromagnetic field variables in the coupled solar wind/magnetosphere system. In this work, we apply a cumulant-based information dynamical measure to characterize the nonlinear dynamics underlying the time evolution of the Dst and Kp geomagnetic indices, given solar wind magnetic field and plasma input. We examine the underlying dynamics of the system, the temporal statistical dependencies, the degree of nonlinearity, and the rate of information loss. We find a significant solar cycle dependence in the underlying dynamics of the system with greater nonlinearity for solar minimum. The cumulant-based approach also has the advantage that it is reliable even in the case of small data sets and therefore it is possible to avoid the assumption of stationarity, which allows for a measure of predictability even when the underlying system dynamics may change character. Evaluations of several leading Kp prediction models indicate that their performances are sub-optimal during active times. We discuss possible improvements …

Anodes of elemental carbon may be discharged in a galvanic cell using a molten carbonate electrolyte, a nickel-foam anode-current collector, and a porous nickel air cathode to achieve power densities of 40-100 mW/cm{sup 2}. We report cell and anode polarization, surface area, primary particle size and a crystallization index for nine particulate carbon samples derived from fuel oil, methane, coal, charred biological material and petroleum coke. At 800 C, current densities of 50-125 mA/cm{sup 2} were measured at a representative cell voltage of 0.8 V. Power densities for cells with two carbon-anode materials were found to be nearly the same on scales of 2.8- and 60 cm{sup 2} active area. Constant current operation of a small cell was accompanied by constant voltage during multiple tests of 10-30 hour duration. Cell voltage fell off after the carbon inventory was consumed. Three different cathode structures are compared, indicating that an LLNL fabricated porous nickel electrode with <10 {micro}m pores provides improved rates compared with nickel foam with 100-300 {micro}m pores. Petroleum coke containing substantial sulfur and ash discharges at a slightly lower rate than purified petroleum coke. The sulfur leads to degradation of the anode current collector over time. A conceptual model …

A new method that combines staggered grid Arbitrary Lagrangian-Eulerian (ALE) techniques with structured local adaptive mesh refinement (AMR) has been developed for solution of the Euler equations. The novel components of the combined ALE-AMR method hinge upon the integration of traditional AMR techniques with both staggered grid Lagrangian operators as well as elliptic relaxation operators on moving, deforming mesh hierarchies. Numerical examples demonstrate the utility of the method in performing detailed three-dimensional shock-driven instability calculations.

OAK-B135 This research work focused on control of the reactive species inside a plasma through measurement and manipulation of the electron energy distribution function (EEDF) and on understanding the surface reaction mechanisms on the substrate exposed to a combination of ion and atom beam sources to simulate a real plasma. A GEC chamber (Gaseous Electronic Conference Reference Cell)8 with a mass spectrometer and a Langmuir probe (LP) system were used for this research. It was found that H2 and N2 additives to an Ar plasma could effectively change the EEDF and the average electron temperature (Te). This finding provides the possibility to selectively control reaction rates in the plasma to control etching selectivity on a surface. This concept was demonstrated in Ar/N2/H2 and Ar/CH4 /H2 systems.

Background: Women who are diagnosed with breast cancer often self-administer complementary and alternative medicines to augment their conventional treatments, improve health, or prevent recurrence. Flor-Essence{reg_sign} Tonic is a complex mixture of herbal extracts used by cancer patients because of anecdotal evidence that it can treat or prevent disease. Methods: Female Sprague Dawley rats were given water or exposed to 3% or 6% Flor-Essence{reg_sign} beginning at one day of age. Mammary tumors were induced with a single oral 40 mg/kg/bw dose of dimethylbenz(a)anthracene at 50 days of age and sacrificed at 23 weeks. Rats were maintained on AIN-76A diet. Results: Control rats had palpable mammary tumor incidence of 51.0% at 19 weeks of age compared to 65.0% and 59.4% for the 3% and 6% Flor-Essence{reg_sign} groups respectively. Overall, no significant difference in time until first palpable tumor was detected among any of the groups. At necropsy, mammary tumor incidence was 82.5% for controls compared to 90.0% and 97.3% for rats consuming 3% and 6% Flor-Essence{reg_sign}, respectively. Mean mammary tumor multiplicity ({+-}SES) for the controls was 2.8 ({+-} 0.5) and statistically different from the 3% or 6% Flor- Essence{reg_sign} groups with 5.2 ({+-} 0.7), and 4.8 ({+-} 0.6), respectively (p{<=}0.01). As expected, …

The radio channel places fundamental limitations on the performance of wireless communication systems in tunnels and caves. The transmission path between the transmitter and receiver can vary from a simple direct line of sight to one that is severely obstructed by rough walls and corners. Unlike wired channels that are stationary and predictable, radio channels can be extremely random and difficult to analyze. In fact, modeling the radio channel has historically been one of the more challenging parts of any radio system design; this is often done using statistical methods. The mechanisms behind electromagnetic wave propagation are diverse, but can generally be attributed to reflection, diffraction, and scattering. Because of the multiple reflections from rough walls, the electromagnetic waves travel along different paths of varying lengths. The interactions between these waves cause multipath fading at any location, and the strengths of the waves decrease as the distance between the transmitter and receiver increases. As a consequence of the central limit theorem, the received signals are approximately Gaussian random process. This means that the field propagating in a cave or tunnel is typically a complex-valued Gaussian random process.

A phase-space discontinuous Galerkin (PSDG) method is presented for the solution of stellar radiative transfer problems. It allows for greater adaptivity than competing methods without sacrificing generality. The method is extensively tested on a spherically symmetric, static, inverse-power-law scattering atmosphere. Results for different sizes of atmospheres and intensities of scattering agreed with asymptotic values. The exponentially decaying behavior of the radiative field in the diffusive-transparent transition region and the forward peaking behavior at the surface of extended atmospheres were accurately captured. The integrodifferential equation of radiation transfer is solved iteratively by alternating between the radiative pressure equation and the original equation with the integral term treated as an energy density source term. In each iteration, the equations are solved via an explicit, flux-conserving, discontinuous Galerkin method. Finite elements are ordered in wave fronts perpendicularly to the characteristic curves so that elemental linear algebraic systems are solved quickly by sweeping the phase space element by element. Two implementations of a diffusive boundary condition at the origin are demonstrated wherein the finite discontinuity in the radiative intensity is accurately captured by the proposed method. This allows for a consistent mechanism to preserve photon luminosity. The method was proved to be robust and …

Measurement of the magnetic field in a spherical torus by observation of harmonic overlap frequencies in the electron Bernstein wave (EBW) spectrum has been previously suggested [V.F. Shevchenko, Plasma Phys. Reports 26 (2000) 1000]. EBW mode conversion to X-mode radiation has been studied in the Current Drive Experiment-Upgrade spherical torus, [T. Jones, Ph.D. thesis, Princeton University, 1995] with emission measured at blackbody levels [B. Jones et al., Phys. Rev. Lett. 90 (2003) article no. 165001]. Sharp transitions in the thermally emitted EBW spectrum have been observed for the first two harmonic overlaps. These transition frequencies are determined by the magnetic field and electron density at the mode conversion layer in accordance with hot-plasma wave theory. Prospects of extending this measurement to higher harmonics, necessary in order to determine the magnetic field profile, and high beta equilibria are discussed for this proposed magnetic field diagnostic.

We present here the first direct and detailed measurements of the spatial distribution of the ionizing radiation surrounding a hadron collider experiment. Using data from two different exposures we measure the effect of additional shielding on the radiation field around the Collider Detector at Fermilab (CDF). Employing a simple model we parameterize the ionizing radiation field surrounding the detector.

Concentrated aqueous solutions (CAS) have unique thermodynamic and physical properties. Chemical components in CAS are incompletely dissociated, especially those containing divalent or polyvalent ions. The problem is further complicated by the interaction between CAS flow processes and the naturally heterogeneous sediments. As the CAS migrates through the porous media, the composition may be altered subject to fluid-rock interactions. To effectively model reactive transport of CAS, we must take into account ion-interaction. A combination of the Pitzer ion-interaction and the ion-association model would be an appropriate way to deal with multiple-component systems if the Pitzer' parameters and thermodynamic data of dissolved components and the related minerals are available. To quantify the complicated coupling of CAS flow and transport, as well as the involved chemical reactions in natural and engineered systems, we have substantially extended an existing reactive biogeochemical transport code, BIO-CORE{sup 2D}{copyright}, by incorporating a comprehensive Pitzer ion-interaction model. In the present paper, the model, and two test cases against measured data were briefly introduced. Finally we present an application to simulate a laboratory column experiment studying the leakage of the high alkaline waste fluid stored in Hanford (a site of the U.S. Department of Energy, located in Washington State, USA). …

A series of coupled neutron-photon transport Monte-Carlo calculations was performed to estimate the roof shielding required to limit the skyshine dose to less than 1 mrem/y at the site boundary when conducting DT experiments with annual fusion yields up to 1200 MJ (4.2E20 neutrons/y). The NIF shielding design consists of many different components. The basic components include 10-cm-thick Al chamber with 40-cm-thick target chamber gunite shield having multiple penetrations, 1.83-m-thick concrete Target Bay walls, 1.37-m-thick concrete roof, and multiple concrete floors with numerous penetrations. Under this shielding configuration, the skyshine dose at the nearest site-boundary was calculated to be less than 0.2 mrem/y for all possible target illumination configurations. The potential dose at the site boundary would be about one-tenth of the cosmic neutron dose that we measured with bubble neutron detectors on board a commercial roundtrip flight from SF to Rochester. This incremental dose increase is well within the normal fluctuations (noise) of the natural background radiation in the Livermore area. The skyshine dose has no impact on the public. The skyshine dose trends at ground and elevated levels are plotted as a function of distance from 20 m to 1000 m from the center of the target bay. …

Installation and commissioning of the first of forty-eight Final Optics Assemblies on the National Ignition Facility was completed this past year. This activity culminated in the delivery of first light to a target. The final optics design is described and selected results from first-article commissioning and performance tests are presented.

There is an urgent need to improve the reliability of screening cargo containers for illicit nuclear material that may be hidden there for terrorist purposes. A screening system is described for detection of fissionable material hidden in maritime cargo containers. The system makes use of a low intensity neutron beam for producing fission; and the detection of the abundant high-energy {gamma} rays emitted in the {beta}-decay of short-lived fission products and {beta}-delayed neutrons. The abundance of the delayed {gamma} rays is almost an order of magnitude larger than that of the delayed neutrons normally used to detect fission and they are emitted on about the same time scale as the delayed neutrons, i.e., {approx}1 min. The energy and temporal distributions of the delayed {gamma} rays provide a unique signature of fission. Because of their high energy, these delayed {gamma} rays penetrate low-Z cargoes much more readily than the delayed neutrons. Coupled with their higher abundance, the signal from the delayed {gamma} rays escaping from the container is predicted to be as much as six decades more intense than the delayed neutron signal, depending upon the type and thickness of the intervening cargo. The {gamma} rays are detected in a large …

The radio channel places fundamental limitations on the performance of wireless communication systems in tunnels and caves. The transmission path between the transmitter and receiver can vary from a simple direct line of sight to one that is severely obstructed by rough walls and corners. Unlike wired channels that are stationary and predictable, radio channels can be extremely random and difficult to analyze. In fact, modeling the radio channel has historically been one of the more challenging parts of any radio system design; this is often done using statistical methods. The mechanisms behind electromagnetic wave propagation are diverse, but can generally be attributed to reflection, diffraction, and scattering. Because of the multiple reflections from rough walls, the electromagnetic waves travel along different paths of varying lengths. The interactions between these waves cause multipath fading at any location, and the strengths of the waves decrease as the distance between the transmitter and receiver increases. As a consequence of the central limit theorem, the received signals are approximately Gaussian random process. This means that the field propagating in a cave or tunnel is typically a complex-valued Gaussian random process.

Identifying and characterizing the patterns of DNA cis-regulatory modules represents a challenge that has the potential to reveal the regulatory language the genome uses to dictate transcriptional dynamics. Several studies have demonstrated that regulatory modules are under positive selection and therefore are often conserved between related species. Using this evolutionary principle we have created a comparative tool, rVISTA, for analyzing the regulatory potential of noncoding sequences. The rVISTA tool combines transcription factor binding site (TFBS) predictions, sequence comparisons and cluster analysis to identify noncoding DNA regions that are highly conserved and present in a specific configuration within an alignment. Here we present the newly developed version 2.0 of the rVISTA tool that can process alignments generated by both zPicture and PipMaker alignment programs or use pre-computed pairwise alignments of seven vertebrate genomes available from the ECR Browser. The rVISTA web server is closely interconnected with the TRANSFAC database, allowing users to either search for matrices present in the TRANSFAC library collection or search for user-defined consensus sequences. rVISTA tool is publicly available at http://rvista.dcode.org/.

Utilizing short-term climatological wind data can enhance wind speed and wind direction forecasts. An analysis of regional or tower-based wind rose summaries can be useful forecast guides especially when synoptic-scale pressure gradients are weak. Predictive data from multiple models can be plotted against short-term climatological wind data to assess deviations from expected norms and differences between forecast models. Site-specific comparisons between predicted data and observed climatological distributions can provide further insights to the forecaster. These methods can be applied to any location where sufficient climatological data (at least two years) is available.

This project developed a prototype system that can rapidly differentiate between undirected cyber attacks, and those that have a more specific and concerning intent behind them. The system responds to important cyber attacks in a tactically significant way as the attack is proceeding. It is also creates a prioritized list for the human analysts allowing them to focus on the threats mostly likely to be of interest. In the recent years the volume of attacks over the internet has increased exponentially, as they have become more and more automated. The result of this is that real threats are harder and harder to distinguish from the general threat. It is possible with our current systems to identify network packets that originated from thousands of IP addresses as probing a site like LLNL in a single day. Human analysis of these threats does not result in information that can be used for tactical response because most of the attacks are short and over before the human starts the analysis. Only a very small percentage of attacks can even be evaluated manually due to the volume. This project developed methods, and prototyped tools, that can identify attacks, slow the attack down and aid …

Precision studies of the top quark are a prime goal of the Run II physics program at the Fermilab Tevatron. Since the start of Run II in early 2002, the CDF and D0 experiments have analyzed approximately 100 pb{sup -1} of data and have re-established the top quark signal. In this article the author summarizes recent measurements of the top production cross section and mass.

In recent years, significant advances have been made in our understanding of the complex flow processes in individual fractures, aided by flow visualization experiments and conceptual modeling efforts. These advances have led to the recognition of several flow regimes in individual fractures subjected to different initial and boundary conditions. Of these, the most important regimes are film flow, rivulet flow, and sliding of droplets. The existence of such significantly dissimilar flow regimes has been a major hindrance in the development of self-consistent conceptual models of flow for single fractures that encompass all the flow regimes. The objective of this study is to delineate the existence of the different flow regimes in individual fractures. For steady-state flow conditions, we developed physical constraints on the different flow regimes that satisfy minimum energy configurations, which enabled us to segregate the wide range of fracture transmissivity (volumetric flow rate per fracture width) into several flow regimes. These are, in increasing order of flow rate, flow of adsorbed films, flow of sliding drops, rivulet flow, stable film flow, and unstable (turbulent) film flow. The scope of this study is limited to wide-aperture fractures with the flow on the opposing sides of fracture being independent.

This paper develops a mathematical model for lithium intercalation and phase change in an iron phosphate-based lithium-ion cell in order to understand the cause for the low power capability of the material. The juxtaposition of the two phases is assumed to be in the form of a shrinking core, where a shell of one phase covers a core of the second phase. Diffusion of lithium through the shell and the movement of the phase interface are described and incorporated into a porous electrode model consisting of two different particle sizes. Open-circuit measurements are used to estimate the composition ranges of the single-phase region. Model-experimental comparisons under constant current show that ohmic drops in the matrix phase, contact resistances between the current collector and the porous matrix, and transport limitations in the iron phosphate particle limit the power capability of the cells. Various design options, consisting of decreasing the ohmic drops, using smaller particles, and substituting the liquid electrolyte by a gel are explored, and their relative importance discussed. The model developed in this paper can be used as a means of optimizing the cell design to suit a particular application.

The objective of this multi-phase project is to demonstrate the feasibility and effectiveness of using full-scale virtual reality simulation in the design, construction, and maintenance of future nuclear power plants. The project will test the suitability of immersive virtual reality technology to aid engineers in the design of the next generation nuclear power plant and to evaluate potential cost reductions that can be realized by optimization of installation and construction sequences. The intent is to see if this type of information technology can be used in capacities similar to those currently filled by full-scale physical mockups. This report presents the results of the completed project.