We propose a partial differential equation (PDE) for filtering and segmentation of echocardiographic images based on a geometric-driven scheme. The method allows edge-preserving image smoothing and a semi-automatic segmentation of the heart chambers, that regularizes the shapes and improves edge fidelity especially in presence of distinct gaps in the edge map as is common in ultrasound imagery. A numerical scheme for solving the proposed PDE is borrowed from level set methods. Results on human in vivo acquired 2D, 2D+time,3D, 3D+time echocardiographic images are shown.

The excellent high temperature strength and thermal conductivity of molybdenum-base alloys provide attractive features for components in advanced magnetic and inertial fusion devices. Refractory metal base alloys react readily with oxygen and other gases, and molybdenum alloys are susceptible to losses from highly volatile molybdenum trioxide (MoOsub3) species. Transport of radioactivity by the volatilization, migration, and re-deposition of MoO3 during a potential accident involving a loss of vacuum or inert environment represents a safety issue. We have experimentally measured the oxidation, volatilization and re-deposition of molybdenum from TZM in flowing air between 400 and 800°C. Calculations using chemical thermodynamic data for vapor pressures over pure MoOsub3 and a vaporization mass transfer model correlate well with experimental data between 600 and 800°C. Partial saturation of (MoOsub3) gas species account for influences of flow rate at 700°C. Some anomalies in oxidation rate below 650°C, suggesting that other phases, e.g., MoOsub2 or other non-stoichiometric oxides may influence oxidation and volatilization processes under some limited conditions.

Emission of “greenhouse gases” into the environment has become an increasing concern. Deregulation of the electrical market will allow consumers to select power suppliers that utilize “green power.” Geothermal power is classed as “green power” and has power emissions of carbon dioxide per kilowatt-hour of electricity than even the cleanest of fossil fuels, natural gas. However, previously published estimates of carbon dioxide emissions are relatively old and need revision. This study estimates that the average carbon dioxide emissions from geothermal and fossil fuel power plants are: geothermal 0.18 , coal 2.13, petroleum 1.56 , and natural gas 1.03 pounds of carbon dioxide per kilowatt-hour respectively.

This paper describes a simple fuel melt slumping model to replace the current parametric model in SCDAP/RELAP5. Specifically, a fuel-coolant interaction (FCI) model is developed to analyze the slumping molten fuel, molten fuel breakup, heat transfer to coolant, relocation of the molten droplets, size of a partially solidified particles that settle to the bottom of the lower plenum, and melt-plenum interaction, if any. Considering our objectives, the molten fuel jet breakup model, and fuel droplets Lagrangian model as included in a code TEXAS-V with Eulerian thermal hydraulics for water and steam from SCDAP/RELAP5 were used. The model was assessed with experimental data from MAGICO-2000 tests performed at University of California at Santa Barbara, and FARO Test L-08 performed at Joint Research Center, Ispra, Italy. The comparison was found satisfactory.

This report addresses the comment on "inflation and flat directions in modular invariant superstring effective theories".

Creep at high stresses often produces strain rates that exceed those that would be predicted by a power law relationship. In this paper, we examine available high stress creep data for pure metals, solid solution alloys, dispersion strengthened powder metallurgy materials and compounds for power law breakdown (PLB). The results show that, if PLB is observed, then the onset of PLB is generally observed at about {epsilon}/D{sub eff} = 10{sup 13} m{sup -2}, where D{sub eff} is the effective diffusion coefficient incorporating lattice and dislocation pipe diffusion. The common origins of PLB for the various systems studied can be found in the production of excess vacancies by plastic deformation. Anomalous behavior in two pure metals (nickel and tungsten) and a solid solution alloy (Fe-25Cr and Fe-26Cr-1Mo) has been analyzed and provides insight into this excess vacancy mechanism. In metal systems, the onset of PLB is related to a change in the nature of the subgrain structure developed. In the PLB region, subgrains become imperfect containing dislocation tangles adjacent to the sub-boundary, and dislocation cells are evident. The dislocation tangles and cells are the source of excess vacancies and increase the creep rate above that predicted from power law creep. If …

Unstabilized hydrogen peroxide of 85% concentration has been prepared in laboratory quantities for testing material compatibility and long term storage on a small scale. Vessels made of candidate tank and liner materials ranged in volume from 1 cc to 2540 cc. Numerous metals and plastics were tried at the smallest scales, while promising ones were used to fabricate larger vessels and liners. An aluminum alloy (6061-T6) performed poorly, including increasing homogeneous decay due to alloying elements entering solution. The decay rate in this high strength aluminum was greatly reduced by anodizing. Better results were obtained with polymers, particularly polyvinylidene fluoride. Data reported herein include ullage pressures as a function of time with changing decay rates, and contamination analysis results.

Automatic cameras were used to record adult woodpecker diets in old-growth and old-field longleaf pine in the South. Roaches were the number one prey for the woodpeckers based on either biomass or numbers. The latter ranged from 37% to 57% of the prey numbers and 55%-73% of the biomass. Morisita's index of similarity between old-field and old growth varied from 0.89 to 0.95. The authors conclude that the prey base is similar in both conditions and that old-growth provides similar foraging habitat.

This document presents the Integrated Safety Management System (ISMS) Description for the Superblock non-reactor nuclear facilities-Tritium Facility (Building 331), Plutonium Facility (Building 332), and Building 334--at the Lawrence Livermore National Laboratory. Building 332 is a Nuclear Hazard Category 2 facility, while Buildings 331 and 334 are Category 3 facilities in accordance with DOE STD-1027, DOE STD-3009, and DOE Order 5480.23. In implementing the Superblock ISMS Description, a graded approach is used--the Category 2 nuclear facility description provides more detail than those for the Category 3 nuclear facilities.

Material removed from carbon bake furnaces used to manufacture anodes for the production of aluminum metal has historically been disposed by landfill. This material is composed primarily of 50% alumina refractory. in 1997, Alcoa completed a highly successful program to reuse the spent refractories in castables for carbon bake furnace headwalls and flooring, as roadbed aggregate, and in other internal applications. This program recycled/reused 11,000 metric tons of used refractory material (99% of the material removed from the carbon bake furnace) and saved Alcoa over 3.8 of the 9.6 million dollar projected furnace rebuild costs. As assessment is made of the performance of the recycled refractory components after two years of service.

Ion-beam optics models for simulating electrostatic prisms (deflectors) of different geometries have been developed for the computer code TRACE 3-D. TRACE 3-D is an envelope (matrix) code, which includes a linear space charge model, that was originally developed to model bunched beams in magnetic transport systems and radiofrequency (RF) accelerators. Several new optical models for a number of electrostatic lenses and accelerator columns have been developed recently that allow the code to be used for modeling beamlines and accelerators with electrostatic components. The new models include a number of options for: (1) Einzel lenses, (2) accelerator columns, (3) electrostatic prisms, and (4) electrostatic quadrupoles. A prescription for setting up the initial beam appropriate to modeling 2-D (continuous) beams has also been developed. The models for electrostatic prisms are described in this paper. The electrostatic prism model options allow the modeling of cylindrical, spherical, and toroidal electrostatic deflectors. The application of these models in the development of ion-beam transport systems is illustrated through the modeling of a spherical electrostatic analyzer as a component of the new low energy beamline at CAMS.

The Single-Column Model (SCM) Working Group (WC) and the Cloud Working Group (CWG) in the Atmospheric Radiation Measurement (ARM) Program have begun a collaboration with the GEWEX Cloud System Study (GCSS) WGs. The forcing data sets derived from the special ARM radiosonde measurements made during the SCM Intensive Observation Periods (IOPs), the wealth of cloud and related data sets collected by the ARM Program, and the ARM infrastructure support of the SCM WG are of great value to GCSS. In return, GCSS brings the efforts of an international group of cloud system modelers to bear on ARM data sets and ARM-related scientific questions. The first major activity of the ARM-GCSS collaboration is a model intercomparison study involving SCMs and cloud system models (CSMs), also known as cloud-resolving or cloud-ensemble models. The SCM methodologies developed in the ARM Program have matured to the point where an intercomparison will help identify the strengths and weaknesses of various approaches. CSM simulations will bring much additional information about clouds to evaluate cloud parameterizations used in the SCMs. CSMs and SCMs have been compared successfully in previous GCSS intercomparison studies for tropical conditions. The ARM Southern Great Plains (SGP) site offers an opportunity for GCSS …

In recent years the rapid increase in processing power of the personal computer has made it a significant competitor to high-end workstations for accelerator control and experimental physics applications. When the decreasing price of the PC and the availability of inexpensive commercial software is also considered, NT becomes a very attractive alternative to traditional UNIX systems. In order to simplify the integration of Personal Computers into our operating environment, we have ported the Control Device (CDEV) Interface to Windows NT. By supporting CDEV on this platform, we can provide routine access to our existing control system. Additionally, CDEV allows us to create an interface from our UNIX workstations to Windows NT applications (such as databases) that are significantly less expensive on the PC. This paper details the pitfalls we encountered during the software migration and will provide a direct comparison between the performance of CDEV applications on UNIX and NT. P articular attention is paid to network performance, which represents most of the overhead of this transition.

Here it is shown that the magnetic linear dichroism in x-ray photoemission (XMLD) signal can be used to measure the element specific magnetic moments in ultra thin alloy films. Comparison with recent SQUID data provides a quantitative check that demonstrates that the total magnetization derived from summing the constituent elemental moments is correct.

A human simulation environment, the Virtual Human (VH), is under development at the Oak Ridge National Laboratory (ORNL). Virtual Human connects three-dimensional (3D) anatomical models of the body with dynamic physiological models to investigate a wide range of human biological and physical responses to stimuli. We have utilized the Java programming language to develop a flexible user interface to the VH. The Java prototype interface has been designed to display dynamic results from selected physiological models, with user control of the initial model parameters and ability to steer the simulation as it is proceeding. Taking advantage of Java�s Remote Method Invocation (RMI) features, the interface runs as a Java client that connects to a Java RMI server process running on a remote server machine. The RMI server can couple to physiological models written in Java, or in other programming languages, including C and FORTRAN. Future versions of the interface will be linked to 3D anatomical models of the human body to complete the development of the VH.

The internal space for a molecule, atom, or other n-body system can be conveniently parameterized by 3n - 9 kinematic angles and three hematic invariants. For a fixed set of kinematic invariants, the kinematic angles parameterize a subspace, called a kinematic orbit, of the n-body internal space. Building on an earlier analysis of the three- and four-body problems, we derive the form of these kinematic orbits (that is, their topology) for the general n-body problem. The case n = 5 is studied in detail, along with the previously studied cases n = 3,4.

We describe a method for computing linear observer statistics for maximum a posteriori (MAP) reconstructions of PET images. The method is based on a theoretical approximation for the mean and covariance of MAP reconstructions. In particular, we derive here a closed form for the channelized Hotelling observer (CHO) statistic applied to 2D MAP images. We show reasonably good correspondence between these theoretical results and Monte Carlo studies. The accuracy and low computational cost of the approximation allow us to analyze the observer performance over a wide range of operating conditions and parameter settings for the MAP reconstruction algorithm.

The interior of the high-intensity Cs-sputter source used in routine operations at the Center for Accelerator Mass Spectrometry (CAMS) has been computer modeled using the program NEDLab, with the aim of improving negative ion output. Space charge effects on ion trajectories within the source were modeled through a successive iteration process involving the calculation of ion trajectories through Poisson-equation-determined electric fields, followed by calculation of modified electric fields incorporating the charge distribution from the previously calculated ion trajectories. The program has several additional features that are useful in ion source modeling: (1) averaging of space charge distributions over successive iterations to suppress instabilities, (2) Child's Law modeling of space charge limited ion emission from surfaces, and (3) emission of particular ion groups with a thermal energy distribution and at randomized angles. The results of the modeling effort indicated that significant modification of the interior geometry of the source would double Cs{sup +} ion production from our spherical ionizer and produce a significant increase in negative ion output from the source. The results of the implementation of the new geometry were found to be consistent with the model results.

The Program for Climate Model Diagnosis and Intercomparison (PCMDI) was established in 1989 at the Lawrence Livermore National Laboratory (LLNL) with the principal mission to develop improved methods and tools for the diagnosis, validation and intercomparison of global climate models. The goal of the process is to eventually improve simulation of the regional climate effects of increasing greenhouse gases. In addition to comparing models, PCMDI continues to develop a modeling infrastructure by creating diagnostics that will be shared throughout the research community. PCMDI's early model intercomparison strategy was to solicit a few models that could be run for a specified period with prescribed sea-surface temperatures after being imported and adapted to the LLNL unclassified computer systems. Because of the enormous time required to prepare each model, the experiment was reversed and the modeling groups were asked to perform the controlled simulations themselves. In order to reach out to the entire atmospheric modeling community, the Working Group for Numerical Experimentation (WGNE) became the parent organization and the project was named the Atmospheric Model Intercomparison Project (AMIP). Eventually, more than thirty atmospheric modeling groups joined the effort to compare their model output (Gates et al. 1999). The general results showed that the …

The effect of shadowing on the early state of ultrarelativistic heavy ion collisions is investigated along with transverse energy and hard process production, specifically Drell-Yan, J/psi, and Upsilon production. We choose several parton distributions and parameterizations of nuclear shadowing, as well as the spatial dependence of shadowing, to study the influence of shadowing on relevant observables. Results are presented for Au+Au collisions at sqrt(s{sub NN}) = 200 GeV and Pb+Pb collisions at sqrt(s{sub NN}) =5.5 TeV.

We have begun building the ''Mercury'' laser system as the first in a series of new generation diode-pumped solid-state lasers for inertial fusion research. Mercury will integrate three key technologies: diodes, crystals, and gas cooling, within a unique laser architecture that is scalable to kilojoule energy levels for fusion energy applications. The primary performance goals include 10% electrical efficiencies at 10 Hz and 100 J with a 2-10 ns pulse length at 1.047 pm wavelength. When completed, Mercury will allow rep-rated target experiments with multiple target chambers for high energy density physics research.

We report a systematic study of the Mn 2p, 3s and 3p core-level photoemission and satellite structures for Mn model compounds. Charge-transfer from the ligand state to the 3d metal state is observed and is distinguished by prominent shake-up satellites. We also observe that the Mn 3s multiplet splitting becomes smaller as the Mn oxidation state increases, and that 3s-3d electron correlation reduces the branching ratio of the 7S:5S states in the Mn 3s spectra. In addition, as the ligand electronegativity decreases, the spin state purity is lost in the 3s spectra as evidenced by peak broadening. Our results are best understood in terms of the configuration-interaction (CI) model including intrashell electron correlation, charge-transfer and final-state screening.

The postgenomic era is arriving faster than anyone had imagined-- sometime during 2000 we'll have a large fraction of the human genome sequence. Heretofore, our understanding of function has come from non-industrial experiments whose conclusions were largely framed in human language. The advent of large amounts of sequence data, and of "functional genomic" data types such as mRNA expression data, have changed this picture. These data share the feature that individual observations and measurements are typically relatively low value adding. Such data is now being generated so rapidly that the amount of information contained in it will surpass the amount of biological information collected by traditional means. It is tantalizing to envision using genomic information to create a quantitative biology with a very strong data component. Unfortunately, we are very early in our understanding of how to "compute on" genomic information so as to extract biological knowledge from it. In fact, some current efforts to come to grips with genomic information often resemble a computer savvy library science, where the most important issues concern categories, classification schemes, and information retrieval. When exploring new libraries, a measure of cataloging and inventory is surely inevitable. However, at some point we will need …

We used a fully coupled climate/chemistry model together with the newly developed IPCC anthropogenic emissions to simulate the climate variation by aerosols. The range of aerosol forcing by the primary indirect effect in next century is estimated between -0.49 and -1.20 W m{sup -2}. This range does not include the potential natural emissions feedbacks associated with climate change. Since sea salt emissions are projected to increase from 88.5 Tg of Na for 2000 to 155 Tg of Na for 2100, the increased aerosol forcing from emissions feedbacks would be mainly over the ocean in southern hemisphere where the maximum is located. More simulations will be performed in order to identify the emissions feedbacks from the total feedbacks. This will provide us a more quantitative range for the aerosol climate forcing as compared to those from greenhouse gases. The magnitudes of climate feedbacks calculated here are subject to uncertainties from climate system. Uncertainty can also arise from the model configuration where the sea surface temperatures are prescribed instead of using a mixed-layer ocean model or a full ocean general circulation model. To quantity these uncertainties, sensitivities tests will be performed in a future study.