Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Required future tests are described that will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures. Future activities also include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining certification for insulated pressure vessels.

A spare NASA/GSFC Astro-E microcalorimeter has been installed, tested, and run successfully on EBIT-II at the Lawrence Livermore National Laboratory. A brief overview of results including measurements by the microcalorimeter of absolute excitation cross sections, time dependent spectra, and spectra as a function of Maxwellian temperature are discussed.

The effect of multiple and delayed jet impact and penetration on the borehole diameter in concrete targets is discussed in this paper. A first-order principle of shaped-charge jet penetration is that target hole volume is proportional to the energy deposited in the target by the jet. This principle is the basis for the relation that target borehole diameter at any depth along the penetration path is proportional to the jet energy deposited in the target at that location. Our current research shows that the 'jet energy per unit hole volume constant' for concrete can be substantially altered by the use of multiple and delayed jet impacts. It has been shown that enhanced entrance crater formation results from the simultaneous impact and penetration of three shaped-charge jets. We now demonstrate that enhanced borehole diameter is also observed by the simultaneous impact and penetration of multiple shaped-charge jets followed by the delayed impact and penetration of a single shaped-charge jet.

Recent work in classification indicates that significant improvements in accuracy can be obtained by growing an ensemble of classifiers and having them vote for the most popular class. This paper focuses on ensembles of decision trees that are created with a randomized procedure based on sampling. Randomization can be introduced by using random samples of the training data (as in bagging or boosting) and running a conventional tree-building algorithm, or by randomizing the induction algorithm itself. The objective of this paper is to describe the first experiences with a novel randomized tree induction method that uses a sub-sample of instances at a node to determine the split. The empirical results show that ensembles generated using this approach yield results that are competitive in accuracy and superior in computational cost to boosting and bagging.

We compare experimental results with simulations of the electron cloud effect induced by a positron beam at the APS synchrotron light source at ANL, where the electron cloud effect has been observed and measured with dedicated probes. We find good agreement between simulations and measurements for reasonable values of certain secondary electron yield (SEY) parameters, most of which were extracted from recent bench measurements at SLAC.

We present simulation results for the emittance blowup due to the head-tail effect induced by the electron-cloud effect (ECE) in the low-energy ring (LER) at the PEP-II B factory at SLAC.

Large samples of hyperon and kaon decays were collected with the Hyper CP spectrometer during two fixed-target runs at Fermilab. Based on an analysis of 110 million K pm decays from the 1997 data sample we present a branching ratio for K pm right arrow pi pm mu+ mu-. This is the first observation of K- right arrow pi- mu+ mu- decay.

Potential impacts of transportation accidents must be addressed in documents prepared under the National Environmental Protection Act (NEPA) as amended or in other environmental-related documents when the transportation of radioactive materials is considered. Estimating the potential human health consequences from the release and dispersion of radioactive materials following such an accident involves a number of interrelated computational models and a variety of input parameters. The RISKIND radiological transportation risk computer program [1] was developed to provide these types of estimates for local scenarios. However, it is often difficult to gain a full understanding of the initial problem and consequences by looking solely at numerical input and tables of results. To permit better-informed decisions, visualization of the site-specific geographic area and the potential spread of contamination can provide greater understanding. Thus, a geographic information system (GIS) component has been integrated with RISKIND to provide visualization capabilities as well as site-specific and computational benefits.

Development of an ANSI/ANS Standard for the training and qualification of criticality safety engineers has been underway for nearly one year. The working group for this Standard is comprised of criticality safety experts from regulatory, licensee and contractor organizations. Its goal is to develop a standard that can be uniformly adopted, that covers all criticality safety engineer qualification levels, and that includes all required competencies such that most of the qualifications can be easily transferred between sites. This status report is presented to let the general criticality safety community know of progress on the Standard, and to solicit feedback to the working group as it continues work on ANSI/ANS-8.26.

The current situation of genomics information exchange is reminiscent of some Third World cities, where residents despair they will ever get official utility service and therefore tap into power, phone, and gas sources with makeshift connections. Thus, each genomics grant spawns yet another idiosyncratic Web site, with makeshift links to whatever random Web sites the PI is most familiar with. There are few standards for semantics of data, and fewer standards for automating the interchange or integration of these autonomous Web sites. The US Plant Genome Initiative (PGI) has been enthusiastic contributor to this proliferation of chaotic Web sites, but to its credit it appears to be the first major program to attempt to find a solution. Some of us from the earliest days of the Human Genome Program have been acutely aware of the problems of genomic data integration, since long before the Web appeared and made the problem exponentially harder to resolve. We have seen large scale attempts, and subsequent failures or inadequacies, of many potential solution approaches (i.e., database federation, classical data warehousing, centralized data, etc.) and believe we know at least some of the reasons they still remain inadequate. It is our opinion that the only …

Most existing computer codes for environmental pathway modeling have been developed to satisfy a specific objective (e.g., perform analyses to demonstrate regulatory compliance). These codes were written in various computer languages and software environments over time and often are not mutually compatible. In recent years, largely driven by advancements in industrial software development, a new concept based on ''modularization'' has emerged. This approach entails the development of common ''modules,'' or components, that can be shared by and used in different applications that have certain common needs. For instance, an air dispersion model can be written as a common component to be shared by several different applications, each with the need to model air dispersion of some material release. When this concept is fully developed, modeling applications would become an exercise of selecting, integrating, and applying a consistent combination of appropriate pre-existing modules for a specific problem. Although modularization holds promising advantages over the traditional approach, a number of issues do exist. These issues must be fully addressed and resolved before the approach can be accepted as a new paradigm for environmental modeling. This paper discusses these issues and provides recommendations and a course of actions for future development.

The role of humic acid (HA) in the biodegradation of toxic polycyclic aromatic hydrocarbons (PAHs) has been the subject of controversy, particularly in unsaturated environments. By utilizing an infrared spectromicroscope and a very bright, nondestructive synchrotron photon source, we monitored in situ and, over time, the influence of HA on the progression of degradation of pyrene (a model PAH) by a bacterial colony on a magnetite surface. Our results indicate that HA dramatically shortens the onset time for PAH biodegradation from 168 to 2 h. In the absence of HA, it takes the bacteria about 168 h to produce sufficient glycolipids to solubilize pyrene and make it bioavailable for biodegradation. These results will have large implications for the bioremediation of contaminated soils.

An article written by Elizabeth Becker for the New York Times about the acknowledgement of the Republican Unity Coalition and inclusion of gay and lesbian people in ceremonies. The piece also speaks about the opinions of the new president George W. Bush and vice president Dick Cheney.

A workshop entitled ''Radionuclide Contamination in Water Resources'' was held in Almaty, Kazakhstan from Tuesday 29 May through Friday 1 June. This workshop was co-sponsored by the U.S. Department of Energy, Lawrence Livermore National Laboratory, and three organizations from the Republic of Kazakhstan: the Institute of Nonproliferation, the Institute of Hydrogeology and Hydrophysics, and KazAtomProm. Representatives from the U.S. Department of Energy, three national laboratories, and 13 different organizations from the Republic of Kazakhstan attended the workshop. A complete list of attendees, the workshop program, and information on the background and motivation for this workshop are provided in this report. The objective of the workshop was to identify critical problems, discover what is known about the problems related to radionuclide contamination of groundwater resources, form collaborative teams, and produce a small number proposals that both address further characterization and assess risk via contaminant fate and transport modeling. We plan to present these proposals to U.S. government agencies and international sponsors for funding.

The corrosion resistance of Alloy 22 (UNS No.: N06022) was studied in simulated ground water of different pH values and ionic contents at various temperatures. Potentiodynamic polarization techniques were used to study the electrochemical behavior and measure the critical potentials in the various systems. Alloy 22 was found to be resistant to localized corrosion in the simulated ground waters tested.

This paper presents a description and analysis of a high-efficiency hydrogen production system. The main component of the system is a novel steam electrolyzer. In conventional electrolyzers, oxygen produced from electrolysis is usually released into the environment. In this design, natural gas is used to react with the oxygen produced in the electrolysis, reducing reduce the chemical potential difference across the electrolyzer, thus minimizing electricity consumption. The oxygen produced from the electrolysis is consumed in either a total oxidation or a partial oxidation reaction with natural gas. Experiments performed on single cells shown a voltage reduction as much as 1 V when compared to conventional electrolyzers. A heat recovery system (heat exchangers and catalytic converter) has been incorporated to the electrolyzer to obtain a high efficiency hydrogen production system. Results from a thermodynamic analysis show up to 70% efficiency with respect to primary energy source.

The 1.5 Tesla superconducting solenoid is part of the BABAR Detector located in the PEP-II B-Factory machine at the Stanford Linear Accelerator Center. The solenoid has a 2.8 m bore and is 3.7 m long. The two layer solenoid is wound with an aluminum stabilized conductor which is graded axially to produce a {+-} 3% field uniformity in the tracking region. The 24 month fabrication, 3 month installation and 1 month commissioning of the solenoid were completed on time and budget. This paper summarizes the culmination of a 3 year design, fabrication and testing program of the BABAR superconducting solenoid. The work was completed by an international collaboration between Ansaldo, INFN, LLNL, and SLAC. Critical current measurements of the superconducting strand, cable and conductor, cool-down, operation with the thermo-siphon cooling, fast and slow discharges, and magnetic forces are discussed in detail.

The cost/performance ratio of networks of workstations has been constantly improving. This trend is expected to continue in the near future. The aggregate peak rate of such systems often matches or exceeds the peak rate offered by the fastest parallel computers. This has motivated research towards using a network of computers, interconnected via a fast network (cluster system) or a simple Local Area Network (LAN) (distributed system), for high performance concurrent computations. Some of the important research issues arise such as (1) Optimal problem partitioning and virtual interconnection topology mapping; (2) Optimal execution scheduling and load balancing. CFD codes have been efficiently implemented on homogeneous parallel systems in the past. In particular, the helicopter aerodynamics CFD code TURNS has been implemented with MPI on the IBM SP with parallel relaxation and Krylov iterative methods used in place of more traditional recursive algorithms to enhance performance. In this implementation the space domain is divided into equal subdomain which are mapped to the processors. We consider the implementation of TURNS on a LAN of heterogeneous workstations. In order to deal with the problem of load balancing due to the different processor speeds we propose a suboptimal algorithm of dividing the space domain …

Detailed chemical kinetic reaction mechanisms are developed for all nine chemical isomers of heptane (C{sub 7}H{sub 16}), following techniques and models developed previously for other smaller alkane hydrocarbon species. These reaction mechanisms are tested at high temperatures by computing shock tube ignition delay times and at lower temperatures by simulating ignition in a rapid compression machine. Although the corresponding experiments have not been reported in the literature for most of these isomers of heptane, intercomparisons between the computed results for these isomers and comparisons with available experimental results for other alkane fuels are used to validate the reaction mechanisms as much as possible. Differences in the overall reaction rates of these fuels are discussed in terms of differences in their molecular structure and the resulting variations in rates of important elementary reactions. Reaction mechanisms in this study are works in progress and the results reported here are subject to change, based on model improvements and corrections of errors not yet discovered.

Numerical simulations are used to visualize the mixing and combustion induced by explosions of spherical and cylindrical TNT charges. Evolution of the exothermic energy is controlled by mixing (vorticity), which is strongly influenced by wave reflections from confining walls.

The steadily increasing power of supercomputing systems is enabling very high resolution simulations of compressible, turbulent flows in the high Reynolds number limit, which is of interest in astrophysics as well as in several other fluid dynamical applications. This paper discusses two such simulations, using grids of up to 8 billion cells. In each type of flow, convergence in a statistical sense is observed as the mesh is refined. The behavior of the convergent sequences indicates how a subgrid-scale model of turbulence could improve the treatment of these flows by high-resolution Euler schemes like PPM. The best resolved case, a simulation of a Richtmyer-Meshkov mixing layer in a shock tube experiment, also points the way toward such a subgrid-scale model. Analysis of the results of that simulation indicates a proportionality relationship between the energy transfer rate from large to small motions and the determinant of the deviatoric symmetric strain as well as the divergence of the velocity for the large-scale field.

The BABAR Detector, located in the PEP-II B-Factory at the Stanford Linear Accelerator Center, includes a large 1.5 Tesla superconducting solenoid, 2.8 m bore and length 3.7 m. The two layer solenoid is wound with an aluminum stabilized conductor which is graded axially to produce a {+-} 3% field uniformity in the tracking region. This paper summarizes the 3 year design, fabrication and testing program of the superconducting solenoid. The work was carried out by an international collaboration between INFN, LLNL and SLAC. The coil was constructed by Ansaldo Energia. Critical current measurements of the superconducting strand, cable and conductor, cool-down, operation with the thermo-siphon cooling, fast and slow discharges, and magnetic forces are discussed in detail.

Adaptive optics for the 30-100 meter class telescopes now being considered will require an extension in almost every area of AO system component technology. In this paper, we present scaling laws and strawman error budgets for AO systems on extremely large telescopes (ELTs) and discuss the implications for component technology and computational architecture. In the component technology area, we discuss the advanced efforts being pursued at the NSF Center for Adaptive Optics (CfAO) in the development of large number of degrees of freedom deformable mirrors, wavefront sensors, and guidestar lasers. It is important to note that the scaling of present wavefront reconstructor algorithms will become computationally intractable for ELTs and will require the development of new algorithms and advanced numerical mathematics techniques. We present the computational issues and discuss the characteristics of new algorithmic approaches that show promise in scaling to ELT AO systems.

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