We determined the cation distribution and ordering of Si, Al and Fe on the tetrahedral sites of a monoclinic low-sanidine from Itrongay, Madagascar, by combined neutron- and X-ray single-crystal diffraction. The cation distribution was determined by means of a simultaneous refinement using neutron- and X-ray data, as well as by combining scattering densities obtained from separate refinements with chemical data from a microprobe experiment. The two methods give the same results and show that Fe is fully ordered on T1, whereas Al shows a high degree of disorder. Based on this and previously published temperature-dependent X-ray data, we conclude that it is preferential ordering of Fe on T1 even at high temperature, rather than a high diffusion kinetics of Fe, which causes this asymmetry in ordering behavior between Al and Fe. The preferential ordering of Fe3+ relative to Al3+ in T1 is consistent with its 25 percent larger ionic radius.

A mobile melt-dilute (MMD) module for the treatment of aluminum research reactor spent fuel is being developed. The process utilizes a closed system approach to retain fission products/gases inside a sealed canister after treatment. The MMD process melts and dilutes spent fuel with depleted uranium to obtain a fissile fraction of less than 0.2. The final ingot is solidified inside the sealed canister and can be stored safely either wet or dry until final disposition or reprocessing. The MMD module can be staged at or near the research reactor fuel storage sites to facilitate the melt-dilute treatment of the spent fuel into a stable non-proliferable form.

A number of materials in and within the proximity of buildings housing fusion energy experiments (FEE) were analyzed for their potential fire hazard. The materials used in this study were mostly: electrical and thermal insulations. The fire hazard of these materials was assessed in terms of their ease of ignition, heat release rate, generation of smoke, and the effect of thermal environment on the combustion behavior. Several fire protection measures for buildings housing the (FEE) projects are analyzed and as a result of this study are found to be adequate for the near term.

There are 6 presentations in this session: (1) Dual harmonic rf operation in the CERN PSB; (2) Using multi-harmonic rf system in the SPS; (3) Blow-up methods tested in the CPS; (4) Broad-band impedance for long bunches; (5) single-bunch instability below transition energy; and (6) Reducing the impedance of the 200 MHz travelling wave cavities.

A brief summary is presented of results pertinent to quark spectroscopy derived from high statistics data on K{sup {minus}}p interactions obtained with the LASS spectrometer at SLAC. The present status of strange meson spectroscopy is briefly reviewed, and the impact of the proposed KAON Factory on the future of the subject considered. 36 refs., 24 figs.

We present the results of applying new object classificationtechniques to difference images in the context of the Nearby SupernovaFactory supernova search. Most current supernova searches subtractreference images from new images, identify objects in these differenceimages, and apply simple threshold cuts on parameters such as statisticalsignificance, shape, and motionto reject objects such as cosmic rays,asteroids, and subtraction artifacts. Although most static objectssubtract cleanly, even a very low false positive detection rate can leadto hundreds of non-supernova candidates which must be vetted by humaninspection before triggering additional followup. In comparison to simplethreshold cuts, more sophisticated methods such as Boosted DecisionTrees, Random Forests, and Support Vector Machines provide dramaticallybetter object discrimination. At the Nearby Supernova Factory, we reducedthe number of non-supernova candidates by a factor of 10 while increasingour supernova identification efficiency. Methods such as these will becrucial for maintaining a reasonable false positive rate in the automatedtransient alert pipelines of upcoming projects such as PanSTARRS andLSST.

We derive a set of moment equations which incorporates linear quadrupolar focusing and space-charge defocusing, in the presence of rotational misalignments of the quadrupoles about the direction of beam propagation. Although the usual beam emittance measured relative to fixed transverse x and y coordinate axes is not constant, a conserved emittance-like quantity has been found. Implications for alignment tolerances in accelerators for heavy-ion inertial fusion are discussed.

Using molecular dynamics (MD) simulation, the authors investigate the mechanical response of silicon to high dose ion-irradiation. The authors employ a realistic model to directly simulate ion beam induced amorphization. Structural properties of the amorphized sample are compared with experimental data and results of other simulation studies. The authors find the behavior of the irradiated material is related to the rate at which it can relax. Depending upon the ability to deform, the authors observe either the generation of a high compressive stress and subsequent expansion of the material, or generation of tensile stress and densification. The authors note that statistical material properties, such as radial distribution functions are not sufficient to differentiate between the different densities of the amorphous samples. For any reasonable deformation rate, the authors observe an expansion of the target upon amorphization in agreement with experimental observations. This is in contrast to simulations of quenching which usually result in a denser structure relative to crystalline Si. The authors conclude that although there is substantial agreement between experimental measurements and simulation results, the amorphous structures being investigated may have fundamental differences; the difference in density can be attributed to local defects within the amorphous network. Finally the …

The authors present a highly efficient molecular dynamics scheme for calculating dopant density profiles in group-IV alloy, and III-V zinc blende structure materials. Their scheme incorporates several necessary methods for reducing computational overhead, plus a rare event algorithm to give statistical accuracy over several orders of magnitude change in the dopant concentration. The code uses a molecular dynamics (MD) model to describe ion-target interactions. Atomic interactions are described by a combination of 'many-body' and pair specific screened Coulomb potentials. Accumulative damage is accounted for using a Kinchin-Pease type model, inelastic energy loss is represented by a Firsov expression, and electronic stopping is described by a modified Brandt-Kitagawa model which contains a single adjustable ion-target dependent parameter. Thus, the program is easily extensible beyond a given validation range, and is therefore truly predictive over a wide range of implant energies and angles. The scheme is especially suited for calculating profiles due to low energy and to situations where a predictive capability is required with the minimum of experimental validation. They give examples of using the code to calculate concentration profiles and 2D 'point response' profiles of dopants in crystalline silicon and gallium-arsenide. Here they can predict the experimental profile over five …

The free flow of information is the feature that has made peer-to-peer information sharing applications popular. However, this very feature holds back the acceptance of these applications by the corporate and scientific communities. In these communities it is important to provide confidentiality and integrity of communication and to enforce access control to shared resources. We present a number of security mechanisms that can be used to satisfy these security requirements. Our solutions are based on established and proven security techniques and we utilize existing technologies when possible. As a proof of concept, we have developed an information sharing system, called scishare, which integrates a number of these security mechanisms to provide a secure environment for information sharing. This system will allow a broader set of user communities to benefit from peer-to-peer information sharing.

Interferometric synthetic aperture radar (IFSAR) extends the two-dimensional imaging capability of traditional synthetic aperture radar to three-dimensions by using an aperture in the elevation plane to estimate the 3-D structure of the target. The operation of this additional aperture can be viewed from a null-steering point of view, rather than the traditional phase determination point of view. Knowing that IFSAR can be viewed from the null-steering perspective allows one to take advantage of the mathematical foundation developed for null-steering arrays. In addition, in some problems of interest in IFSAR the null-steering perspective provides better intuition and suggests alternative solutions. One example is the problem of estimating building height where layover is present.

Fermentation of glucose-xylose mixtures to ethanol was investigated in batch and continuous experiments using immobilized recombinant <i>Zymomonas mobilis</i> CP4(pZB5). This microorganism was immobilized by entrapment in k-carrageenan beads having a diameter of 1.5-2.5 mm. Batch experiments showed that the immobilized cells co-fermented glucose and xylose to ethanol and that the presence of glucose improved the xylose utilization rate. Batch fermentation of rice straw hydrolyzate containing 76 g/L glucose and 33.8 g/L xylose gave an ethanol concentration of 44.3 g/L after 24 hours, corresponding to a yeild of 0.46 g ethanol/g sugars. Comparable results were achieved with a synthetic sugar control. Continuous fermentation runs were performed in a laboratory scale fluidized-bed bioreactor (FBR). Glucose-xylose feed mixtures were run through the FBR at residence times of 2 to 4 hours. Glucose conversion to ethanol was maintained above 98% in all continuous runs. Xylose conversion to ethanol was highest at 91.5% for a feed containing 50 g/L glucose-13 g/L xylose at a dilution rate of 0.24 h^-1. The xylose conversion to ethanol decreased with increasing feed xylose concentration, dilution rate and age of the immobilized cells. Volumetric ethanol productivities in the range of 6.5 to 15.3 g/L-h were obtained.

The Lawrence Livermore National Laboratory (LLNL) is participating in a US Department of Energy sponsored multi-laboratory cooperative effort with the Russian Federation nuclear institutes to reduce risks of nuclear weapons proliferation by strengthening systems of nuclear materials protection, control, and accounting in both countries. This program is called the Laboratory-to-Laboratory Nuclear Materials Protection, Control, and Accounting (MPC&A) Program and it is designed to complement other US-Russian MPC&A programs such as the government-to-govermment (NunnLugar) programs. LLNL`s role in this program has been to collaborate with various Russian institutes in several areas. One of these is integrated safeguards and security planning and analysis, including the performing of vulnerability assessments. In the area of radiation measurements LLNL is cooperating with various institutes on gamma-ray measurement and analysis techniques for plutonium and uranium accounting. LLNL is also participating in physical security upgrades including entry control and portals.

Since fall 2001, Livermore Computing at Lawrence Livermore National Laboratory has deployed 11 Intel IA-32-based Linux clusters ranging in size up to 1154 nodes. All provide a common programming model and implement a similar cluster architecture. Hardware components are carefully selected for performance, usability, manageability, and reliability and are then integrated and supported using a strategy that evolved from practical experience. Livermore Computing Linux clusters run a common software environment that is developed and maintained in-house while drawing components and additional support from the open source community and industrial partnerships. The environment is based on Red Hat Linux and adds kernel modifications, cluster system management, monitoring and failure detection, resource management, authentication and access control, development environment, and parallel file system. The overall strategy has been successful and demonstrates that world-class high-performance computing resources can be built and maintained using commodity off-the-shelf hardware and open source software.

A Bremsstrahlung spectrometer using k-edge and differential filtering has been used with Image Plate dosimeters to measure the x-ray fluence from short-pulse laser/target interactions. An electron spectrometer in front of the Bremsstrahlung spectrometer deflects electrons from the x-ray line of sight and simultaneously measures the electron spectrum. The response functions were modeled with the Monte Carlo code Integrated Tiger Series 3.0 and the dosimeters calibrated with radioactive sources. Electron distributions with slope temperatures in the MeV range are inferred from the Bremsstrahlung spectra.

Seismic responses of the Zion nuclear power generation complex accounting for structure-to-structure interaction effects as predicted by CLASSI and FLUSH Codes are presented in this paper. Two aspects of the multi-structure analyses were considered: the effect of structure-to-structure interaction on structure response and the variability in structure response as predicted by different codes, including structure-to-structure interaction. The effect of structure- to-structure interaction on the response of the Zion reactor building and AFT complex (the auxiliary/fuel-handling/turbine building complex) was assessed by comparing the results of CLASSI analyses with and without interaction between structures. The results show that the reactor building has a very small effect on the AFT complex, but the effect of structure-to-structure interaction on the reactor building from the AFT complex is substantial. A comparison of the reactor building`s response as predicted by CLASSI and FLUSH, structures including structure-to-structure interaction, shows significant differences. Modeling three-dimensional configuration of a complicated power plant structure such as the Zion`s with equivalent two-dimensional models for structure-to-structure interaction analysis requires careful consideration.

The authors use a sample of 384 million B{bar B} events collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider to study angular distributions in the rare decays B {yields} K*{ell}{sup +}{ell}{sup -}, where {ell}{sup +}{ell}{sup -} is either e{sup +}e{sup -} or {mu}{sup +}{mu}{sup -}. For low dilepton invariant masses, m{sub {ell}{ell}} &lt; 2.5 GeV/c{sup 2}, they measure a lepton forward-backward asymmetry {Alpha}{sub FB} = 0.24{sub -0.23}{sup +0.18} {+-} 0.05 and K* longitudinal polarization F{sub L} = 0.35 {+-} 0.16 {+-} 0.04. For m{sub {ell}{ell}} &gt; 3.2 GeV/c{sup 2}, they measure {Alpha}{sub FB} = 0.76{sub -0.32}{sup +0.52} {+-} 0.07 and F{sub L} = 0.71{sub -0.22}{sup 0.20} {+-} 0.04.

The volumetric heating of a thin copper target has been studied with time resolved x-ray spectroscopy. The copper target was heated from a plasma produced using the Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) laser. A variable spaced grating spectrometer coupled to an x-ray streak camera measured soft x-ray emission (800-1550 eV) from the back of the copper target to characterize the bulk heating of the target. Radiation hydrodynamic simulations were modeled in 2-dimensions using the HYDRA code. The target conditions calculated by HYDRA were post-processed with the atomic kinetics code CRETIN to generate synthetic emission spectra. A comparison between the experimental and simulated spectra indicates the presence of specific ionization states of copper and the corresponding electron temperatures and ion densities throughout the laser-heated copper target.

We are developing a non-interceptive beam profile and energy monitor for H{sup -} beams in the high energy beam transport (HEBT) line at the Brookhaven National Lab linac. Electrons that are removed from the beam ions either by laser photodetachment or stripping by background gas are deflected into a Faraday cup. The beam profile is measured by stepping a narrow laser beam across the ion beam and measuring the electron charge vs. transverse laser position. There is a grid in front of the collector that can be biased up to 125kV. The beam energy spectrum is determined by measuring the electron charge vs. grid voltage. Beam electrons have the same velocity as the beam and so have an energy of 1/1836 of the beam protons. A 200MeV H{sup -} beam yields 109keV electrons. Energy measurements can be made with either laser-stripped or gas-stripped electrons.

Four ionization profile monitors (IPMs) are in RHIC to measure vertical and horizontal beam profiles in the two rings. These work by measuring the distribution of electrons produced by beam ionization of residual gas. During the last two years both the collection accuracy and signal/noise ratio have been improved. An electron source is mounted across the beam pipe from the collector to monitor microchannel plate (MCP) aging and the signal electrons are gated to reduce MCP aging and to allow charge replenishment between single-turn measurements. Software changes permit simultaneous measurements of any number of individual bunches in the ring. This has been used to measure emittance growth rates on six bunches of varying intensities in a single store. Also the software supports FFT analysis of turn-by-turn profiles of a single bunch at injection to detect dipole and quadrupole oscillations.

An infrastructure of new and existing pipelines and systems will be required to carry and to deliver hydrogen as an alternative energy source under the hydrogen economy. Carbon and low alloy steels of moderate strength are currently used in hydrogen delivery systems as well as in the existing natural gas systems. It is critical to understand the material response of these standard pipeline materials when they are subjected to pressurized hydrogen environments. The methods and results from a testing program to quantify hydrogen effects on mechanical properties of carbon steel pipeline and pipeline weld materials are provided. Tensile properties of one type of steel (A106 Grade B) in base metal, welded and heat affected zone conditions were tested at room temperature in air and high pressure (10.34 MPa or 1500 psig) hydrogen. A general reduction in the materials ability to plastically deform was noted in this material when specimens were tested in hydrogen. Furthermore, the primary mode of fracture was changed from ductile rupture in air to cleavage with secondary tearing in hydrogen. The mechanical test results will be applied in future analyses to evaluate service life of the pipelines. The results are also envisioned to be part of the …

None

The Computing and Communications Division at the Los Alamos National Laboratory has designed and is building a parallel microprocessor system (PuPS) to serve as a research tool for evaluating parallel processing of large-scale scientific codes. PuPS is an experimental architecture consisting of an orthogonal array of 20 processing elements by 32 memory elements, establishing a tightly coupled, shared-memory (16-Mbyte) machine. The hardware incorporates VLSI components, such as 16-bit microprocessors, floating-point co-processors, and dynamic random access memories. The design replaces conventional MSI/SSI circuitry with programmable array logic, logic sequencers, and logic arrays. This experimental system, which is only 1 element of the parallel processing research being done by the Laboratory's Computing and Communications Division, will enable direct comparisons of speedups of algorithms for a variety of multiprocessor architectures.

As described in the License Application Design Selection Report, the recommended waste, package design is Engineering Design Alternative II (CRWMS M&amp;O 1999). This design includes a double-wall waste package (WP) underneath a protective drip shield (DS). purpose and scope of the process-level model described here is to account for both general and localized corrosion of the waste package outer barrier (WPOB), which assumed to be Alloy 22 (UNS N06022-21Cr-13Mo-4Fe-3W-2C-Ni) (ASTM 1997a). This model will include several sub-models, which will account for dry oxidation (DOX), humid air corrosion (HAC), general corrosion (GC) in the aqueous phase, and localized corrosion (LC) the aqueous phase. This model serves as a feed to the waste package degradation (WAPDEG) code for performance, assessment.