The pulse radiolysis of N2O saturated aqueous solutions of KSCN was studied under neutral pH conditions. The observed optical absorption spectrum of the SCN• radical in solution is more complex than previously reported, but it is in good agreement with that measured in the gas phase. Kinetic traces at 330 nm and 472 nm corresponding to SCN• and (SCN)2•¯, respectively, were fit using a Monte Carlo simulation kinetic model. The rate coefficient for the oxidation of SCN¯ ions by OH radicals, an important reaction used in competition kinetics measurements, was found to be 1.4 ± 0.1 x 1010 M-1 s-1, about 30 % higher than the normally accepted value. A detailed discussion of the reaction mechanism is presented.

Ion-optics calculations were performed for a new ion source and injection beam line. This source, which can accept both solid and gaseous targets, will be installed onto the 1-MV BioAMS spectrometer at the Center for Accelerator Mass Spectrometry, located at Lawrence Livermore National Laboratory and will augment the current LLNL cesium-sputter solid sample ion source. The ion source and its associated injection beam line were designed to allow direct quantification of {sup 14}C/{sup 12}C and {sup 3}H/{sup 1}H isotope ratios from both solid and gaseous targets without the need for isotope switching. Once installed, this source will enable the direct linking of a nanoflow LC system to the spectrometer to provide for high-throughput LC-AMS quantitation from a continuous flow. Calculations show that, for small samples, the sensitivity of the gas-accepting ion source could be precision limited but zeptomole quantitation should be feasible.

The California Water Resources Control Board, in collaboration with the US Geological Survey and Lawrence Livermore National Laboratory, has implemented a program to assess the susceptibility of groundwater resources. Advanced techniques such as groundwater age dating using the tritium-helium method, extensive use of oxygen isotopes of the water molecule ({delta}{sup 18}O) for recharge water provenance, and analysis of common volatile organic compounds (VOCs) at ultra-low levels are applied with the goal of assessing the contamination vulnerability of deep aquifers, which are frequently used for public drinking water supply. Over 1200 public drinking water wells have been tested to date, resulting in a very large, tightly spaced collection of groundwater ages in some of the heavily exploited groundwater basins of California. Smaller scale field studies that include shallow monitoring wells are aimed at assessing the probability that nitrate will be transported to deep drinking water aquifers. When employed on a basin-scale, groundwater ages are an effective tool for identifying recharge areas, defining flowpaths, and determining the rate of transport of water and entrained contaminants. De-convolution of mixed ages, using ancillary dissolved noble gas data, gives insight into the water age distribution drawn at a well, and into the effective dilution of …

This paper presents two new strategies to speed up connectedcomponent labeling algorithms. The first strategy employs a decisiontreeto minimize the work performed in the scanning phase of connectedcomponent labeling algorithms. The second strategy uses a simplifiedunion-find data structure to represent the equivalence information amongthe labels. For 8-connected components in atwo-dimensional (2D) image,the first strategy reduces the number of neighboring pixels visited from4 to7/3 on average. In various tests, using a decision tree decreases thescanning time by a factor of about 2. The second strategy uses a compactrepresentation of the union-find data structure. This strategysignificantly speeds up the labeling algorithms. We prove analyticallythat a labeling algorithm with our simplified union-find structure hasthe same optimal theoretical time complexity as do the best labelingalgorithms. By extensive experimental measurements, we confirm theexpected performance characteristics of the new labeling algorithms anddemonstrate that they are faster than other optimal labelingalgorithms.

A new mechanism for the oxidation of methylcyclohexane has been developed. The mechanism combined a newly-developed low temperature mechanism with a previously developed high temperature mechanism. Predictions from the chemical kinetic model have been compared to experimentally measured ignition delay times from a rapid compression machine. Predicted ignition delay times using the initial estimates of the methylcyclohexyl peroxy radical isomerization rate constants were much longer than those measured at low temperatures. The initial estimates of isomerization rate constants were modified based on the experimental findings of Gulati and Walker that indicate a much slower rate of isomerization. Predictions using the modified rate constants for isomerizations yielded faster ignition at lower temperatures that greatly improved the agreement between model predictions and the experimental data. These findings point to much slower isomerization rates for methylcyclohexyl peroxy radicals than previously expected.

The 3D Morse-Smale complex is a fundamental topological construct that partitions the domain of a real-valued function into regions having uniform gradient flow behavior. In this paper, we consider the construction and selective presentation of cells of the Morse-Smale complex and their use in the analysis and visualization of scientific datasets. We take advantage of the fact that cells of different dimension often characterize different types of features present in the data. For example, critical points pinpoint changes in topology by showing where components of the level sets are created, destroyed or modified in genus. Edges of the Morse-Smale complex extract filament-like features that are not explicitly modeled in the original data. Interactive selection and rendering of portions of the Morse-Smale complex introduces fundamental data management challenges due to the unstructured nature of the complex even for structured inputs. We describe a data structure that stores the Morse-Smale complex and allows efficient selective traversal of regions of interest. Finally, we illustrate the practical use of this approach by applying it to cryo-electron microscopy data of protein molecules.

Office equipment is expected to be the fastest-growingsegment of commercial energy use over the next 20 years, yet many aspectsof office equipment energy use are poorly understood. User behavior, suchas turning off devices at night or enabling power management, influencesenergy use to a great extent. The computing environment also plays a roleboth in influencing user behavior and in the success of power management.Information about turn-off rates and power management rates for officeequipment was collected through a series of after-hours audits incommercial buildings. Sixteen businesses were recruited, includingoffices (small, medium and large offices in a variety of industries),schools, and medical buildings in California, Georgia, and Pennsylvania.The types and power states of office equipment found in these buildingswere recorded and analyzed. This article presents these data forcomputers, monitors, printers, copiers, fax machines, scanners andmulti-function devices. These data can be used to improve estimates ofboth energy consumption for these devices and savings from energyconservation efforts.

One approach for heating a target to ''Warm Dense Matter'' conditions (similar, for example, to the interiors of giant planets or certain stages in Inertial Confinement Fusion targets), is to use intense ion beams as the heating source (see refs.[6] and [7] and references therein for motivation and accelerator concepts). By consideration of ion beam phase space constraints, both at the injector, and at the final focus, and consideration of simple equations of state and relations for ion stopping, approximate conditions at a target foil may be calculated. Thus target temperature and pressure may be calculated as a function of ion mass, ion energy, pulse duration, velocity tilt, and other accelerator parameters. We connect some of these basic parameters to help search the extensive parameter space (including ion mass, ion energy, total charge in beam pulse, beam emittance, target thickness and density).

The seesaw mechanism that explains the small neutrino masses comes naturally with supersymmetric (SUSY) grand unification and leptogenesis. However, the framework suffers from the SUSY flavor and CP problems, and has a severe cosmological gravitino problem. We propose anomaly mediation as a simple solution to all these problems, which is viable once supplemented by the D-terms for U(1)_Y and U(1)_B-L. Even though the right-handed neutrino mass explicitly breaks U(1)_B-L and hence reintroduces the flavor problem, we show that it lacks the logarithmic enhancement and poses no threat to the framework. The thermal leptogenesis is then made easily consistent with the gravitino constraint.

Universal extra dimensions and supersymmetry have rather similar experimental signatures at hadron colliders. The proper interpretation of an LHC discovery in either case may therefore require further data from a lepton collider. In this paper we identify methods for discriminating between the two scenarios at the linear collider. We study the processes of Kaluza-Klein muon pair production in universal extra dimensions in parallel to smuon pair production in supersymmetry, accounting for the effects of detector resolution, beam-beam interactions and accelerator induced backgrounds. We find that the angular distributions of the final state muons, the energy spectrum of the radiative return photon and the total cross-section measurement are powerful discriminators between the two models. Accurate determination of the particle masses can be obtained both by a study of the momentum spectrum of the final state leptons and by a scan of the particle pair production thresholds. We also calculate the production rates of various Kaluza-Klein particles and discuss the associated signatures.

We construct the New Minimal Standard Model that incorporates the new discoveries of physics beyond the Minimal Standard Model (MSM): Dark Energy, non-baryonic Dark Matter, neutrino masses, as well as baryon asymmetry and cosmic inflation, adopting the principle of minimal particle content and the most general renormalizable Lagrangian. We base the model purely on empirical facts rather than aesthetics. We need only six new degrees of freedom beyond the MSM. It is free from excessive flavor-changing effects, CP violation, too-rapid proton decay, problems with electroweak precision data, and unwanted cosmological relics. Any model of physics beyond the MSM should be measured against the phenomenological success of this model.

We implanted ultra low doses (0.2 to 2 x 10{sup 11} cm{sup -2}) of Sb ions into isotopically enriched {sup 28}Si, and probed electrical activation and electron spin relaxation after rapid thermal annealing. Strong segregation of dopants towards both Si{sub 3}N{sub 4} and SiO{sub 2} interfaces limits electrical activation. Pulsed Electron Spin Resonance shows that spin echo decay is sensitive to the dopant profiles, and the interface quality. A spin decoherence time, T{sub 2}, of 1.5 ms is found for profiles peaking 25 nm below a Si/SiO{sub 2} interface, increasing to 2.1 ms when the surface is passivated with hydrogen. These measurements provide benchmark data for the development of devices in which quantum information is encoded in donor electron spins.

Support was provided by DOE for the 2nd ASM Conference on Prokaryotic Development. The final conference program and abstracts book is attached. The conference presentations are organized around topics that are central to the current research areas in prokaryotic development. The program starts with topics that involve relatively simple models systems and ends with systems that are more complex. The topics are: i) the cell cycle, ii) the cytoskeleton, iii) morphogenesis, iv) developmental transcription, v) signaling, vi) multicellularity, and vii) developmental diversity and symbiosis. The best-studied prokaryotic development model systems will be highlighted at the conference through research presentations by leaders in the field. Many of these systems are also model systems of relevance to the DOE mission including carbon sequestration (Bradyrizobium, Synechococcus), energy production (Anabaena, Rhodobacter) and bioremediation (Caulobacter, Mesorhizobium). In addition, many of the highlighted organisms have important practical applications; the actinomycetes and myxobacteria produce antimicrobials that are of commercial interest. It is certain that the cutting-edge science presented at the conference will be applicable to the large group of bacteria relevant to the DOE mission.

A hot, T{sub e} {approx} 2- to 3-keV surface plasma was observed in the interaction of a 0.7-ps petawatt laser beam with solid copper-foil targets at intensities >10{sup 20} W/cm{sup 2}. Copper K-shell spectra were measured in the range of 8 to 9 keV using a single-photon-counting x-ray CCD camera. In addition to K{sub {alpha}} and K{sub {beta}} inner-shell lines, the emission contained the Cu He{sub {alpha}} and Ly{sub {alpha}} lines, allowing the temperature to be inferred. These lines have not been observed previously with ultrafast laser pulses. For intensities less than 3 x 10{sup 18} W/cm{sup 2}, only the K{sub {alpha}} and K{sub {beta}} inner-shell emissions are detected. Measurements of the absolute K{sub {alpha}} yield as a function of the laser intensity are in agreement with a model that includes refluxing and confinement of the suprathermal electrons in the target volume.

The inverse Free Electron Laser (IFEL) interaction has recently been proposed and used as a short wavelength modulator for micro bunching of beams for laser acceleration experiments [1,2]. These experiments utilized the fundamental of the interaction between the laser field and electron bunch. In the current experiment, we explore the higher order resonances of the IFEL interaction from a 3 period, 1.8 centimeter wavelength undulator with a picosecond, 0.5 mJ/pulse laser at 800nm. The resonances are observed by adjusting the gap of the undulator while keeping the beam energy constant. We also compare the experimental results to a simple analytic model that describes coupling to high order harmonics of the interaction.

We have carried out numerical simulations of three-dimensional non-isothermal flow around an in situ heat-based flow sensor to investigate how formation heterogeneities can affect the interpretation of ground water flow velocities from this instrument. The flow sensor operates by constant heating of a 0.75 m long, 5 cm diameter cylindrical probe, which contains 30 thermistors in contact with the formation. The temperature evolution at each thermistor can be inverted to obtain an estimate of the ground water flow velocity vector using the standard interpretive method, which assumes that the formation is homogeneous. Analysis of data from heat-based flow sensors installed in a sand aquifer at the Former Fort Ord Army Base near Monterey, California suggested an unexpected component of downward flow. The magnitudes of the vertical velocities were expected to be much less than the horizontal velocities at this site because the sensors were installed just above a clay aquitard. Numerical simulations were conducted to examine how differences in thermal conductivities may lead to spurious indications of vertical flow velocities. We found that a decrease in the thermal conductivity near the bottom of the sensor can perturb the temperature profiles along the instrument in such a manner that analyses assuming …

For three days in late September last year, some sixty experts in RF superconductivity from around the world came together at Argonne to discuss how to push the limits of RF superconductivity for particle accelerators. It was an intense workshop with in-depth presentations and ample discussions. There was added excitement due to the fact that, a few days before the workshop, the International Technology Recommendation Panel had decided in favor of superconducting technology for the International Linear Collider (ILC), the next major high-energy physics accelerator project. Superconducting RF technology is also important for other large accelerator projects that are either imminent or under active discussion at this time, such as the Rare Isotope Accelerator (RIA) for nuclear physics, energy recovery linacs (ERLs), and x-ray free-electron lasers. For these accelerators, the capability in maximum accelerating gradient and/or the Q value is essential to limit the length and/or operating cost of the accelerators. The technological progress of superconducting accelerators during the past two decades has been truly remarkable, both in low-frequency structures for acceleration of protons and ions as well as in high-frequency structures for electrons. The requirements of future accelerators demand an even higher level of performance. The topics of this …

In-situ Spatially Resolved X-Ray Diffraction (SRXRD) experiments were performed during gas tungsten arc (GTA) welding of AISI 1045 C-Mn steel. Ferrite ({alpha}) and austenite ({gamma}) phases were identified and quantified in the weld heat-affected zone (HAZ) from the real time x-ray diffraction data. The results were compiled along with weld temperatures calculated using a coupled thermal fluids weld model to create a phase map of the HAZ. This map shows the {alpha} {yields} {gamma} transformation taking place during weld heating and the reverse {gamma} {yields} {alpha} transformation taking place during weld cooling. Superheating is required to complete the {alpha} {yields} {gamma} phase transformation, and the amount of superheat above the A3 temperature was shown to vary with distance from the centerline of the weld. Superheat values as high as 250 C above the A3 temperature were observed at heating rates of 80 C/s. The SRXRD experiments also revealed details about the {gamma} phase not observable by conventional techniques, showing that {gamma} is present with two distinct lattice parameters as a result of inhomogeneous distribution of carbon and manganese in the starting pearlitic/ferritic microstructure. During cooling, the reverse {gamma} {yields} {alpha} phase transformation was shown to depend on the HAZ location. …

A hybrid spectral/compact solver for variable-density viscous incompressible flow is described. Parallelization strategies for the FFTs and band-diagonal matrices are discussed and compared. Transpose methods are found to be highly competitive with direct block parallel methods when the problem is scaled to tens of thousands of processors. Various mapping strategies for the IBM BlueGene/L torus configuration of processors are explored. By optimizing the communication, we have achieved virtually perfect scaling to 32768 nodes. Furthermore, communication rates come very close to the theoretical peak speed of the BlueGene/L network with sustained computation in the TeraFLOPS range.

The e{sup +}e{sup -} {yields} p{bar p} cross-section is determined over a range of p{bar p} masses, from threshold to 4.5 GeV/c{sup 2}, by studying the e{sup +}e{sup -} {yields} p{bar p}{gamma} process. The data set corresponds to an integrated luminosity of 232 fb{sup -1}, collected with the BABAR detector at the PEP-II storage ring, at an e{sup +}e{sup -} center-of-mass energy of 10.6 GeV. The mass dependence of the ratio of electric and magnetic form factors, |G{sub E}/G{sub M}|, is measured for p{bar p} masses below 3 GeV/c{sup 2}; its value is found to be significantly larger than 1 for masses up to 2.2 GeV/c{sup 2}. We also measure J/{psi} {yields} p{bar p} and {psi}(2S) {yields} p{bar p} branching fractions and set an upper limit on Y(4260) {yields} p{bar p} production and decay.

Recent experiments at the Institute of Laser Engineering (ILE) in Japan [1] and at Rutherford Appleton Laboratory (RAL) in the United Kingdom [2] have shown good coupling of short-pulse high-intensity laser light into high-energy electrons channeled down a narrow fiber. Such target configurations are being considered as backlighter targets on the National Ignition Facility (NIF). We will report on LSP calculations of these cone-wire experiments and other candidate target configurations. These calculations also give insight into the transport of MeV-electrons, which remains the critical issue for the achievement of fast ignition [3]. The LSP code uses a direct implicit particle-in-cell (PIC) algorithm in 2 or 3 dimensions to solve for beam particle transport, while treating the background particles as a fluid [4]. We have modified LSP to produce K{alpha} photons in a non-interfering manner and will show calculated absolute K{alpha} yields for the experiments reported by Key [2].

The double spherical harmonics angular approximation in the lowest order, i.e. double P{sub 0} (DP{sub 0}), is developed for the solution of time-dependent non-equilibrium grey radiative transfer problems in planar geometry. Although the DP{sub 0} diffusion approximation is expected to be less accurate than the P{sub 1} diffusion approximation at and near thermodynamic equilibrium, the DP{sub 0} angular approximation can more accurately capture the complicated angular dependence near a non-equilibrium radiation wave front. In addition, the DP{sub 0} approximation should be more accurate in non-equilibrium optically thin regions where the positive and negative angular domains are largely decoupled. We develop an adaptive angular technique that locally uses either the DP{sub 0} or P{sub 1} flux-limited diffusion approximation depending on the degree to which the radiation and material fields are in thermodynamic equilibrium. Numerical results are presented for two test problems due to Su and Olson and to Ganapol and Pomraning for which semi-analytic transport solutions exist. These numerical results demonstrate that the adaptive P{sub 1}-DP{sub 0} diffusion approximation can yield improvements in accuracy over the standard P{sub 1} diffusion approximation, both without and with flux-limiting, for non-equilibrium grey radiative transfer.

A responsibility of the Laser Safety Officer (LSO) is to perform laser audits. The American National Standard Z136.1 Safe Use of Lasers references this requirement through several sections. One such reference is Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''. The composition, frequency and rigor of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms It is common for audit findings from one inspector or inspection to the next to vary even when reviewing the same material. How often has one heard a comment, ''well this area has been inspected several times over the years and no one ever said this or that was a problem before''. A great number of audit items, and therefore findings, are subjective because they are based on the experience and interest of the auditor to particular items on the checklist. Beam block usage, to one set of eyes might be completely adequate, while to another, inadequate. In order to provide consistency, the Laser Safety Office of the National Ignition Facility …

In this paper, we use a coupled climate and carbon cycle model to investigate the global climate and carbon cycle changes out to year 2300 that would occur if CO2 emissions from all the currently estimated fossil fuel resources were released to the atmosphere. By year 2300, the global climate warms by about 8 K and atmospheric CO2 reaches 1423 ppmv. In our simulation, the prescribed cumulative emission since pre-industrial period is about 5400 Gt-C by the end of 23rd century. At year 2300, nearly 45 % of cumulative emissions remain in the atmosphere. In our simulations both soils and living biomass are net carbon sinks throughout the simulation. Despite having relatively low climate sensitivity and strong carbon uptake by the land biosphere, our model projections suggest severe long-term consequences for global climate if all the fossil-fuel carbon is ultimately released to the atmosphere.