We update a discussion of the relation between the weak phase and the rates and CP asymmetries of several K{pi} decays of B{sup +}, B{sup 0}, and B{sub s}. We emphasize the impact of measurements of B{sub s} {yields} K{pi}. Current data indicate large SU(3) breaking in the strong phases or failure of factorization (including its application to penguin amplitudes) in K{pi} modes of B{sup 0} and B{sub s}. SU(3) and factorization only remain approximately valid if the branching ratio for B{sub s} {yields} K{sup -}{pi}{sup +} exceeds its current value of (5.00 {+-} 1.25) x 10{sup -6} by at least 50%, or if a parameter {zeta} describing ratios of form factors and decay constants is shifted from its nominal value by more than twice its estimated error.

Black carbon (BC), a main component of combustion-generated soot, is a strong absorber of sunlight and contributes to climate change. Measurement methods for BC are uncertain, however. This study presents a method for analyzing the BC mass loading on a quartz fiber filter using a modified thermal-optical analysis method, wherein light transmitted through the sample is measured over a spectral region instead of at a single wavelength as the sample is heated. Evolution of the spectral light transmission signal depends on the relative amounts of light-absorbing BC and char, the latter of which forms when organic carbon in the sample pyrolyzes during heating. Absorption selectivities of BC and char are found to be distinct and are used to apportion the amount of light attenuated by each component in the sample. Light attenuation is converted to mass concentration based on derived mass attenuation efficiencies (MAE) of BC and char. The fraction of attenuation due to each component are scaled by their individual MAE values and added together as the total mass of light absorbing carbon (LAC). An iterative algorithm is used to find the MAE values for both BC and char that provide the best fit to the carbon mass remaining …

The development of radiological consequence lookup tables for postulated releases of radionuclides commonly used at Savannah River Site (SRS) and other Department of Energy (DOE) facilities requires the use of the MELCOR Accident Consequence Code System (MACCS)/MACCS2. MACCS2 users input site-specific data: such as stack or ground release, building wake effects, boundary distance from release source, and site-specific meteorological data. MACCS2 also allows the input of more general data such as plume rise and wet and/or dry deposition. The acceptance of such inputs gives the MACCS2 program a broad spectrum of uses at participating DOE facilities. The MACCS2 outputs are converted to an excel spreadsheet to facilitate fast and accurate results for various accident scenarios. Consequence lookup tables can be employed to determine the effects of radiological accident scenarios before they occur. The data is then used by DOE facilities to create regulations and controls to prepare for worst-case scenarios.

Petascale systems will present several new challenges to performance and correctness tools. Such machines may contain millions of cores, requiring that tools use scalable data structures and analysis algorithms to collect and to process application data. In addition, at such scales, each tool itself will become a large parallel application--already, debugging the full Blue-Gene/L (BG/L) installation at the Lawrence Livermore National Laboratory requires employing 1664 tool daemons. To reach such sizes and beyond, tools must use a scalable communication infrastructure and manage their own tool processes efficiently. Some system resources, such as the file system, may also become tool bottlenecks. In this paper, we present challenges to petascale tool development, using the Stack Trace Analysis Tool (STAT) as a case study. STAT is a lightweight tool that gathers and merges stack traces from a parallel application to identify process equivalence classes. We use results gathered at thousands of tasks on an Infiniband cluster and results up to 208K processes on BG/L to identify current scalability issues as well as challenges that will be faced at the petascale. We then present implemented solutions to these challenges and show the resulting performance improvements. We also discuss future plans to meet the debugging …

Reliability, Availability, and Maintainability (RAM) studies are extensively used for mission critical systems (e.g., weapons systems) to predict the RAM parameters at the preliminary design phase. A RAM methodology is presented for predicting facility/laboratory inherent availability (i.e., availability that only considers the steady-state effects of design) at the preliminary design phase in support of Department of Energy (DOE) Order 430.1A (Life Cycle Asset Management) and DOE Order 420.1B (Facility Safety). The methodology presented identifies the appropriate system-level reliability and maintainability metrics and discusses how these metrics are used in a fault tree analysis for predicting the facility/laboratory inherent availability. The inherent availability predicted is compared against design criteria to determine if changes to the facility/laboratory preliminary design are necessary to meet the required availability objective in the final design.

The fracture toughness properties of Type 21-6-9 stainless steel were measured for forgings in the unexposed, hydrogen-exposed, and tritium-exposed-and-aged conditions. Fracture toughness samples were cut from conventionally-forged and high-energy-rate-forged forward-extruded cylinders and mechanically tested at room temperature using ASTM fracture-toughness testing procedures. Some of the samples were exposed to either hydrogen or tritium gas (340 MPa, 623 K) prior to testing. Tritium-exposed samples were aged for up to seven years and tested periodically in order to measure the effect on fracture toughness of {sup 3}He from radioactive tritium decay. The results show that hydrogen-exposed and tritium-exposed samples had lower fracture- toughness values than unexposed samples and that fracture toughness decreased with increasing decay {sup 3}He content. Forged steels were more resistant to the embrittling effects of tritium and decay {sup 3}He than annealed steels, although their fracture-toughness properties depended on the degree of sensitization that occurred during processing. The fracture process was dominated by microvoid nucleation, growth and coalescence; however, the size and spacing of microvoids on the fracture surfaces were affected by hydrogen and tritium with the lowest-toughness samples having the smallest microvoids and finest spacing.

In contrast to previous analyses, we demonstrate a Bayesian approach to the estimation of the CKM phase {alpha} that is invariant to parameterization. We also show that in addition to computing the marginal posterior in a Bayesian manner, the distribution must also be interpreted from a subjective Bayesian viewpoint. Doing so gives a very natural interpretation to the distribution. We also comment on the effect of removing information about {beta}{sup 00}.

The reaction of ozone with the (100) plane of solid potassium iodide (KI) was investigated using atomic force microscopy (AFM). The reaction forming potassium iodate (KIO{sub 3}) initiates at step edges prior to reacting on the flat terraces. Small domains of KIO{sub 3}, initially 3.8 {angstrom} in height are formed on the top of step edges. Following reaction at the step edge, domains of KIO{sub 3} are formed across the terraces. With prolonged exposure to ozone, KIO{sub 3} domains nucleate further growth until the surface is evenly covered with KIO{sub 3} particles that are 4-6 nm in height, at which point the surface is passivated and the reaction terminates.

One of the emerging computational approaches in nuclear physics is the full configuration interaction (FCI) method for solving the many-body nuclear Hamiltonian in a sufficiently large single-particle basis space to obtain exact answers - either directly or by extrapolation. The lowest eigenvalues and correspondingeigenvectors for very large, sparse and unstructured nuclear Hamiltonian matrices are obtained and used to evaluate additional experimental quantities. These matrices pose a significant challenge to the design and implementation of efficient and scalable algorithms for obtaining solutions on massively parallel computer systems. In this paper, we describe the computational strategies employed in a state-of-the-art FCI code MFDn (Many Fermion Dynamics - nuclear) as well as techniques we recently developed to enhance the computational efficiency of MFDn. We will demonstrate the current capability of MFDn and report the latest performance improvement we have achieved. We will also outline our future research directions.

We study the Collins mechanism contribution to the single transverse spin asymmetry in inclusive hadron production in pp scattering p{up_arrow}p {yields} {pi}X from the leading jet fragmentation. The azimuthal asymmetric distribution of hadron in the jet leads to a single spin asymmetry for the produced hadron in the Lab frame. The effect is evaluated in a transverse momentum dependent model that takes into account the transverse momentum dependence in the fragmentation process. We find the asymmetry is comparable in size to the experimental observation at RHIC at {radical}s = 200GeV.