The current waste package design for the proposed repository at Yucca Mountain Nevada, USA, employs gas tungsten arc welding (GTAW) in fabricating the waste packages. While GTAW is widely used in industry for many applications, it requires multiple weld passes. By comparison, single-pass welding methods inherently use lower heat input than multi-pass welding methods which results in lower levels of weld distortion and also narrower regions of residual stresses at the weld TWI Ltd. has developed a Reduced Pressure Electron Beam (RPEB) welding process which allows EB welding in a reduced pressure environment ({le} 1 mbar). As it is a single-pass welding technique, use of RPEB welding could (1) achieve a comparable or better materials performance and (2) lead to potential cost savings in the waste package manufacturing as compared to GTAW. Results will be presented on the initial evaluation of the RPEB welding on a Ni-Cr-Mo alloy (a candidate alloy for the Yucca Mountain waste packages) in the areas of (a) design and manufacturing simplifications, (b) material performance and (c) weld reliability.

This paper discusses issues with the limited precision of hardware-based volume visualization. We will describe the compositing OVER operator and how fixed-point arithmetic affects it. We propose two techniques to improve the precision of fixed-point compositing and the accuracy of hardware-based volume visualization. The first technique is to perform dithering of color and alpha values. The second technique we call exponent-factoring, and captures significantly more numeric resolution than dithering, but can only produce monochromatic images.

Recent measurements of the infrared (IR) absorption coefficient of CH and CD capsules differ significantly from earlier estimated values from thin flat samples. The optimum wavelength for IR enhanced layering of DT and D{sub 2} ice layers inside of a NIF scale hohlraum depends on the relative ice and capsule absorption coefficients. This update of a previous memo shows the maximum ice heating with IR as a function of ice and capsule absorption instead of at discrete wavelengths. Also discussed is the leverage of other parameters, such as the IR absorption of the hohlraum wall and thermal conductivities of the support rods and exchange gas. The most likely capsule and ice absorption values limit the IR heating to between 2-7 Q{sub DT}. We find most leverage of the IR heating comes from increasing the ice to capsule absorption ratio. As before, this is the conduction only limit to IR, with convection potentially playing a large role.

Radiative corrections to the decay rate of n = 2 states of hydrogenic ions are calculated. The transitions considered are the M1 decay of the 2s state to the ground state and the E1(M2) decays of the 2p{sub 1/2} and 2p{sub 3/2} states to the ground state. The radiative corrections start in order {alpha}(Z{alpha}){sup 2}, but the method used sums all orders of Z{alpha}. The leading {alpha}(Z{alpha}){sup 2} correction for the E1 decays is calculated and compared with the exact result. The extension of the calculational method to parity nonconserving transitions in neutral atoms is discussed.

Large simulation codes can take on the order of hours to compile from scratch. In Kull, which uses generic programming techniques, a significant portion of the time is spent generating and compiling template instantiations. I would like to investigate methods that would decrease the overall compilation time for large codes. These would be methods which could then be applied, hopefully, as standard practice to any large code. Success is measured by the overall decrease in wall clock time a developer spends waiting for an executable. Analyzing the make system of a slow to build project can benefit all developers on the project. Taking the time to analyze the number of processors used over the life of the build and restructuring the system to maximize the parallelization can significantly reduce build times. Distributing the build across multiple machines with the same configuration can increase the number of available processors for building and can help evenly balance the load. Becoming familiar with compiler options can have its benefits as well. The time improvements of the sum can be significant. Initial compilation time for Kull on OSF1 was {approx} 3 hours. Final time on OSF1 after completion is 16 minutes. Initial compilation time …

With a sample of approximately 89 million B{bar B} pairs collected with the BABAR detector, they measure branching fractions, determine the degree of longitudinal polarization, and search for direct CP violation in the decays B{sup 0} {yields} {phi}K*{sup 0} and B{sup +} {yields} {phi}K*{sup +}. They perform a search for other charmless vector-vector B decays involving {rho} and K*(892) resonances and observe the decays B{sup +} {yields} {rho}{sup 0} K*{sup +} and B{sup +} {yields} {rho}{sup 0}{rho}{sup +}. The branching fractions are measured to be {Beta}({phi}K*{sup 0}) = (11.1{sub -1.2}{sup +1.3} {+-} 1.1) x 10{sup -6}, {Beta}({phi}K*{sup +}) = (12.1{sub -1.9}{sup +2.1} {+-} 1.5) x 10{sup -6}, {Beta}({rho}{sup 0} K*{sup +}) = (7.7{sub -2.0}{sup +2.1} {+-} 1.4) x 10{sup -6}, and {Beta}({rho}{sup 0}{rho}{sup +}) = (9.9{sub -2.5}{sup +2.6} {+-} 2.5) x 10{sup -6}. The longitudinal polarization fractions are measured to be {Lambda}{sub L}/{Lambda}({phi}K*{sup 0}) = 0.65 {+-} 0.07 {+-} 0.04 and {Lambda}{sub L}/{Lambda}({phi}K*{sup +}) = 0.46 {+-} 0.12 {+-} 0.05. They measure the charge asymmetries: {Alpha}{sub CP}({phi}K*{sup 0}) = +0.04 {+-} 0.12 {+-} 0.02 and {Alpha}{sub CP}({phi}K*{sup +}) = +0.16 {+-} 0.17 {+-} 0.04.

The well-known spatial variation of packing fraction near the outer boundary of a pebble-bed reactor core is cited. The ramifications of this variation are explored with the MCNP computer code. It is found that the variation has negligible effects on the global reactor physics parameters extracted from the MCNP calculations for use in analysis by diffusion-theory codes, but for local reaction rates the effects of the variation are naturally important. Included is some preliminary work in using first-order perturbation theory for estimating the effect of the spatial variation of packing fraction on the core eigenvalue and the fission density distribution.

Pathological detonation waves with velocities greater than Chapman-Jouguet (C-J) have been proposed theoretically but never observed experimentally in gaseous, liquid or solid explosives. Two types of pathological chemical reaction zones have been identified within the Zeldovich-von Neumann-Doring (ZND) model: an exothermic chemical decomposition with a mole decrease during from the von Neumann spike state to the C-J state and an exothermic reaction followed by an endothermic reaction (eigenvalue detonation). The high temperatures reached in detonation reaction zones cause sufficient radial and atom formation to insure overall mole increases in gaseous H{sub 2} + O{sub 2} detonations. Aluminized explosives exhibit a slight mole decrease when the solid aluminum particles are oxidized, but this does not negate the large mole increase that occurs during explosive decomposition. Porous solid explosives whose products form with more cold compression energy than that of the solid are an unlikely possibility for pathological detonation. Eigenvalue detonations have been postulated for H{sub 2} + Cl{sub 2} gas phase detonations and for plastic bonded solid explosives if endothermic binder decomposition follows exothermic explosive decomposition. Chemical kinetic and physical arguments are presented to eliminate these possible pathological detonations. In the case of H{sub 2} + Cl{sub 2}, highly vibrationally excited …

The natural vantage point for performing Earth-centric operations from space is geosynchronous orbit (GEO); a platform there moves at the same rate as the Earth's surface, so appears to continually ''hover'' over a fixed site on the Earth. Unlike spacecraft in other orbits, which rapidly fly-over targets, a GEO-based platform remains in-position all the time. In order to insure continual access to sites using low earth orbit (LEO) platforms, one needs a large enough constellation ({approx} 50) of spacecraft so that one is always overhead; in contrast, a single GEO platform provides continuous coverage over sites throughout Euro-Asia. This permanent coverage comes, unfortunately, with a stiff price-tag; geosynchronous orbit is 36,000 km high, so space platforms there must operate at ranges roughly 100 times greater than ones located in LEO. For optical-based applications, this extreme range is difficult to deal with; for surveillance the price is a 100-fold loss of resolution, for laser weapons it is a 10,000-fold loss in flux-on-target. These huge performance penalties are almost always unacceptable, preventing us from successfully using GEO-based platforms. In practice, we are forced to either settle for brief, infrequent access to targets, or, if we demand continuous coverage, to invest in large, …

The core focus of this hydroacoustic research is to develop a better understanding of hydroacoustic blockage to better predict those stations that can be used in discrimination analysis for any particular event. The research involves two approaches: (1) model-based assessment of blockage and (2) ground-truth data-based assessment of blockage. The goal is to reliably determine all hydroacoustic stations that can be brought to bear on a discrimination analysis from any event location in the world s oceans. An important aspect of this capability is to include reflected T-phases where they reliably occur since reflected T-phases can allow station utilization when the direct path is otherwise completely blocked. We have conceptually designed an approach to automate assessment procedures that will allow both model-based and data-based methodologies to be utilized and in the future, integrated. We have modified the HydroCAM model-based network assessment code to include variable density bathymetry grids. This will improve the reliability of model-based blockage assessment as dense bathymetry grids are added to the bathymetry database where available and needed. We are also running the HydroCAM code to produce blockage grids in the Indian Ocean for many different blockage criteria. We have been building the database necessary to begin …

Lawrence Livermore National Laboratory (LLNL) has developed a mass spectrometer-based system that measures organic surface residues in situ. This system, called the Contamination Analysis Unit (CAU), can detect and quantify a variety of volatile surface residues on a range of different substrates. Residue samples are removed from the substrate using a combination of vacuum and thermal desorption, and are then ionized and quantified by a quadrupole mass spectrometer. The current effort (Phase 2) was carried out in accordance with Thiokol Project Test Plan PTP-0467. A first phase of tests was completed under PTP-0327 and the results reported in TWR-75385. The Phase 2 test plan, PTP-0467, is a follow-on to PTP-0327, and was conducted in order to more fully determine the capabilities of the CAU. This report summarizes experiments in which the CAU was evaluated for application in reusable solid rocket motor production scenarios. The report has been ordered by the tasks requested by ATK Thiokol Propulsion Testplan PTP-0467. Project tasks included the following: (1) Determine the amount of residual propellant and liner components with the CAU after coupons have been cleaned. (2) Determine if the CAU can detect solvent that has soaked into NBR. (3) Test the capabilities of the …

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Two reference artifacts will be fabricated for this study. One of the artifacts will have a cylindrical geometry and will contain features similar to those on an SNRT target. The second artifact will have a spherical geometry and will contain features similar to those on a Double Shell target. The artifacts were designed for manufacturability and to provide a range of features that can be measured using NDE methods. The cylindrical reference artifact is illustrated in Figure 1. This artifact consists of a polystyrene body containing two steps and a machined slot, into which will fit a tracer made of doped polystyrene. The polystyrene body contains several grooves and can be fabricated entirely on a diamond turning machine. The body can be machined by turning a PS rod to a diameter slightly greater than the finished diameter of 2 mm. The part can be moved off-axis to face it off and to machine the steps, slot, and grooves. The tracer contains a drilled hole and a milled slot, which could be machined with a single setup on a milling machine. Once assembled, the artifact could be placed in a Be tube or other structure relevant to target assemblies. The assembled …

Multiple access (MA) in UWB communication is an area of active research. To date several time-division or code-division pulse amplitude modulation (PAM) or pulse position modulation (PPM) schemes have been proposed to separate multiple users in UWB communications. Conventionally, all users employ the same pulse shape and modulate the transmit pulse based on changing amplitude or position. One concern with using the same pulse for all channels is that the multiple access interference (MAI) increases as the number of users increase. This is due to increased cross-correlation between similar pulses of the different channels, raising thus the noise floor in such systems. In this paper we introduce and study the performance of a new MA scheme in the context of multiple orthogonal transmitted-reference (T-R) short duration (nsec) chirp pulses in the presence of multipath and additive white Gaussian noise (AWGN).

In plasma or rarified gas physics, collisions are rare but non-ignorable events. To model systems with arbitrary collisonality, it is necessary to start with a model that is fully capable of capturing collisionless, kinetic behavior. It is also necessary to build strategies to provide the essential economies into the scheme as collisions become more frequent. The desired model should progress smoothly and continuously from collisionless particle dynamics to collision-dominated fluid. We are developing a new approach [Hewett, JCP 2003; Larson, JCP 2003] to recover the physics of this partially collisional regime. Our approach, called CPK (for Collisional Particle Kinetics) is basically a ''smart particle'' PIC scheme with particles that have internal parameters representing internal ''fluid'' behavior as the CPK particles become large via merging. In the collisionless limit, the individual macro particles become numerous, small and cold through fragmentation--leading naturally to the traditional PIC limit. The new ''smart'' particle is a Gaussian distribution in all phase space directions. An arbitrary distribution of real particles can be made as a superposition of these ''particles''. One of the key capabilities is the ability to fragment each particle in a way that will not introduce new physics. With this procedure we can replace …

Adaptive optics uses signal processing techniques and deformable mirrors to minimize image degradation caused by phase aberrations. In the case of telescope imaging, the atmosphere causes phase aberrations. In the case of satellite imaging, errors due to the ultra-light-weight characteristics of the primary mirror cause phase aberrations. Scene-based Shack-Hartmann Wave Front Sensing takes the correlation between successive wavelets to determine these phase aberrations. A large problem with the scene-based approach is that motion, such as a moving car, can cause the correlation of two lenslets to peak, not where the scenes align, but where the moving object in each frame aligns. As such, the continued use of scene-based Wave Front Sensing necessitates successful isolation of moving objects from a stationary background scene. With the knowledge of which pixels are immobile, one should avoid the problem of locking onto a moving object when taking the correlation of two successive frames in time. Two main requirements of isolation are consistency and efficiency. In this document I will discuss the different edge detection algorithms explored for moving object isolation and how I came to the conclusion that, for our purposes of scene-based Shack-Hartmann WFS, edge detection is too inconsistent to be of any …

Given a Morse function f over a 2-manifold with or without boundary, the Reeb graph is obtained by contracting the connected components of the level sets to points. We prove tight upper and lower bounds on the number of loops in the Reeb graph that depend on the genus, the number of boundary components, and whether or not the 2-manifold is orientable. We also give an algorithm that constructs the Reeb graph in time O(n log n), where n is the number of edges in the triangulation used to represent the 2-manifold and the Morse function.

Experiments that investigate thermal and nearby explosion scenarios are needed to provide essential data to models for accurate predictions. A porous LX-04 (85/15 wt% HMX/Viton) sample was heated in a heavily confined donor charge until it thermally exploded. The reaction accelerated a steel cover plate across a 10 cm gap into a preheated gauged acceptor cylinder (near its theoretical maximum density) of LX-04. The carbon resistor gauges in the acceptor measured the resulting multi-dimensional ramp wave as it propagated through the pre-heated LX-04. Detonation of the LX-04 acceptor does not occur. Results are compared to similar experiments with acceptors at room temperature.

A dynamical description of atomic mixing in multicomponent gases and plasmas was summarized in a previous report (UCRL-ID-145502). That description is based on the use of separate continuity and momentum equations for each species present, including neutral atoms, ions, and free electrons. This level of detail is not always feasible in practical problems, where subsets of species (e.g., neutral atoms of a particular element together with their ionization products) must be grouped or lumped together into composite species or materials to make the problem tractable. A simple procedure for constructing such composite species was outlined in UCRL-ID-145502, but not in sufficient detail to enable implementation. In particular, the treatment of the free electrons presents some subtleties, since they cannot be included in the composite species for dynamical purposes, whereas they are ordinarily lumped together with the atoms and ions that produced them for state equation purposes. Our purpose here is to provide a more complete description of the procedure by which composite species and their evolution equations may be defined and derived. Special attention is given to the problem of how to deal with the free electrons in a manner consistent with the different roles they play in the dynamics …

The Lawrence Livermore National Laboratory (LLNL) has a long history of developing high power lasers for use in basic science and applications. The Laser Science and Technology Program (LS&T) at LLNL supports advanced lasers and optics development both for the National Ignition Facility (NIF) as well as for high power lasers and optics technology for a broader range of government, military and industrial applications. The NIF laser is currently under construction with the first of the 192 beamlines being activated. When finished NIF will have an output energy of 2 MJ at 351 nm. This system will be used for studies of high energy density physics, equation of state and inertial confinement fusion. It is now generally acknowledged that the future of laser missile defense lies with solid state lasers. The leading laser technology for theater missile defense is under development within the LS&T and funded by the US Army SMDC. This high average power technology is based on a solid state laser operated in a heat capacity mode. In the concept the heat producing lasing cycle is separated in time from the cooling cycle thus reducing thermal gradients and allowing significantly greater average output power. Under the current program, …

The objective of this evaluation was to determine whether a single rotating pump located 20 ft off-center would adequately mix expected AN-101 waste. Three-dimensional, AN-101 pump jet mixing simulation results indicate that a single, 20-ft off-centered mixer pump would mobilize almost all solids even at the furthest tank wall for sludge yield strength up to 150 Pa or less. Because the yield strength of the AN-101 waste was estimated to be less than 150 Pa, the AN-101 pump mixing model results indicate that a single mixer pump would be suffice to mobilize bulk of the disturbed and diluted AN-101 solids.

The study of the electrochemical behavior of wrought and welded Alloy 22 was carried out in 5 M CaCl{sub 2} between 45 and 120 C. Comparisons were made between the electrochemical behaviors of the wrought and welded forms of Alloy 22 Multiple Crevice Assembly (MCA) specimens. The susceptibility to corrosion was found to increase with increase in temperature in both the wrought and the welded forms of the alloy. The weld metal was found to be less susceptible to localized corrosion under the conditions tested.

The first experiments on the National Ignition Facility (NIF) have employed the first four beams to measure propagation and laser backscattering losses in large ignition-size plasmas. Gas-filled targets between 2 mm and 7 mm length have been heated from one side by overlapping the focal spots of the four beams from one quad operated at 351 nm (3{omega}) with a total intensity of 2 x 10{sup 15} W cm{sup -2}. The targets were filled with 1 atm of CO{sub 2} producing of up to 7 mm long homogeneously heated plasmas with densities of n{sub e} = 6 x 10{sup 20} cm{sup -3} and temperatures of T{sub e} = 2 keV. The high energy in a NIF quad of beams of 16kJ, illuminating the target from one direction, creates unique conditions for the study of laser plasma interactions at scale lengths not previously accessible. The propagation through the large-scale plasma was measured with a gated x-ray imager that was filtered for 3.5 keV x rays. These data indicate that the beams interact with the full length of this ignition-scale plasma during the last {approx}1 ns of the experiment. During that time, the full aperture measurements of the stimulated Brillouin scattering and …

Time Resolved X-Ray Diffraction (TRXRD) experiments were used to directly observe phase transformations occurring during gas tungsten arc spot welding of Ti-6Al-4V. These in-situ x-ray diffraction experiments tracked the evolution of the {alpha} {yields} {beta} {yields} L {yields} {beta} {yields} {alpha}/{alpha}{prime} phase transformation sequence in real time during rapid weld heating and cooling. Three different weld locations were examined, providing kinetic information about phase transformations in the fusion zone (FZ) and heat affected zone (HAZ) under different heating and cooling rates and at different temperatures. The TRXRD data were further coupled with the results of thermodynamic calculations of phase equilibria and numerical modeling to compute the weld temperatures. The results suggest that significant superheat is required above the {beta} transus temperature to complete the {alpha} {yields} {beta} transformation at all locations during weld heating, and that the amount of superheat decreases with distance from the center of the weld where the heating rates are lower. Johnson-Mehl-Avrami modeling of the weld heating kinetics produced a set of parameters that allowed the prediction of the {alpha} {yields} {beta} phase transformation rate at each location, but were not successful in determining a definitive mechanism for the transformation. The {beta} {yields} {alpha} transformation during …