Over the last several years, significant progress has been made in the use of crystal level material models in simulations of forming operations. However, in Lagrangian finite element approaches simulation capabilities are limited in many cases by mesh distortion associated with deformation heterogeneity. Contexts in which such large distortions arise include: bulk deformation to strains approaching or exceeding unity, especially in highly anisotropic or multiphase materials; shear band formation and intersection of shear bands; and indentation with sharp indenters. Investigators have in the past used Eulerian finite element methods with material response determined from crystal aggregates to study steady state forming processes. However, Eulerian and Arbitrary Lagrangian-Eulerian (ALE) finite element methods have not been widely utilized for simulation of transient deformation processes at the crystal level. The advection schemes used in Eulerian and ALE codes control mesh distortion and allow for simulation of much larger total deformations. We will discuss material state representation issues related to advection and will present results from ALE simulations.

We point out that aspects of quantum mechanics can be derived from the holographic principle, using only a perturbative limit of classical general relativity. In flat space, the covariant entropy bound reduces to the Bekenstein bound. The latter does not contain Newton's constant and cannot operate via gravitational backreaction. Instead, it is protected by--and in this sense, predicts--the Heisenberg uncertainty principle.

The primary focus for the project continues to be on developing a PC PREHEAT system design suitable for use with caking coals and readying the 100 MMBtu/h CBTF for testing with noncaking PRB coal. During the current quarter, twenty-two pilot tests were conducted with Central Appalachian (CA) caking coal. The objective for these tests was to achieve continuous operation of the pilot system at its design coal feed rate of 156 lb/h, without plugging or agglomeration in the combustor. One combustor air distribution method tested achieved continuous operation at 110 lb/hr, and inspection of the combustor afterward indicated that this method has potential to solve the caking problem. The NOx results from the pilot caking coal runs indicate that even greater NOx reduction is possible with CA coal than with the PRB coal tested, to levels near 100 ppmv or lower at 4-6% exit oxygen. It was therefore decided to conduct additional pilot tests of the air distribution method to determine how to incorporate this into a workable CA combustor design. Based on current weather and manpower restrictions at the site, this pilot testing is expected to be started in February. The design for the 100 MMBtu/h unit for PRB …

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Radiocarbon ({sup 14}C) in the skeletal aragonite of annually banded corals track radiocarbon concentrations in dissolved inorganic carbon (DIC) in surface seawater. As a result of nuclear weapons testing in the 1950s, oceanic uptake of excess {sup 14}C in the atmosphere has increased the contrast between surface and deep ocean {sup 14}C concentrations. We present accelerator mass spectrometric (AMS) measurements of radiocarbon isotope ({Delta}{sup 14}C) in Porites corals from the Mentawai Islands, Sumatra (0 S, 98 E) and Watamu, Kenya (3 S, 39 E) to document the temporal and spatial evolution of the {sup 14}C gradient in the tropical Indian Ocean. The rise in {Delta}{sup 14}C in the Sumatra coral, in response to the maximum in nuclear weapons testing, is delayed by 2-3 years relative to the rise in coral {Delta}{sup 14}C from the coast of Kenya. Kenya coral {Delta}{sup 14}C values rise quickly because surface waters are in prolonged contact with the atmosphere. In contrast, wind-induced upwelling and rapid mixing along the coast of Sumatra entrains {sup 14}C-depleted water from the subsurface, which dilutes the effect of the uptake of bomb-laden {sup 14}C by the surface-ocean. Bimonthly AMS {Delta}{sup 14}C measurements on the Mentawai coral reveal mainly interannual variability …

This is the Final Technical Report describing the achievements on this DOE program. This research program was initiated with the objective of obtaining a better understanding of the flow, and especially the superplastic flow, of representative ceramics. Detailed experiments were undertaken on the yttria-stabilized tetragonal zirconia (Y-TZP) and on various composite materials containing Y-TZP and Al{sub 2}O{sub 3}. In addition, a comprehensive theoretical interpretation was developed which showed, for the first time, that the superplasticity of ceramic materials has very significant differences from the conventional superplastic flow in metals.

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is a stadium-sized facility containing a 192-beam, 1.8-Megajoule, 500-Terawatt, ultraviolet laser system together with a 10-meter-diameter target chamber and room for 100 diagnostics. NIF is the world's largest and most energetic laser experimental system, providing a scientific center to study inertial confinement fusion and matter at extreme energy densities and pressures. NIF's energetic laser beams will compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. Other NIF experiments will study physical processes at temperatures approaching 10{sup 8} K and 10{sup 11} bar; conditions that exist naturally only in the interior of stars and planets. NIF has completed the first phases of its laser commissioning program. The first four beams of NIF have generated 106 kilojoules in 23-ns pulses of infrared light and over 16 kJ in 3.5-ns pulses at the third harmonic (351 nm). NIF's target experimental systems are being commissioned and experiments have begun. This paper provides a detailed look the NIF laser systems, laser and optical performance, and results from recent laser commissioning shots. We follow this with a discussion of NIF's high-energy-density and inertial fusion experimental capabilities, …

Hydrofluoric acid is a water solution of hydrogen fluoride (HF). Hydrofluoric acid is used widely in diverse types of industrial applications; traditionally, it is used in pickling solutions in the metal industry, in the fabrication of chlorofluorocarbon compounds, as an alkylation agent for gasoline and as an etching agent in the industry of glass. In recent years, hydrofluoric acid has extensively been used in the manufacture of semiconductors and microelectronics during the wet chemical cleaning of silicon wafers. Hydrofluoric acid can be considered a reducing acid and although it is chemically classified as weaker than, for example, sulfuric or hydrochloric acids, it is extremely corrosive. This acid is also particularly toxic and poses greater health hazard than most other acids. The corrosion behavior of metals in hydrofluoric acid has not been as systematic studied in the laboratory as for other common inorganic acids. This is largely because tests using hydrofluoric acid cannot be run in standard equipment and because of the toxic nature of this acid. Moreover, short-term weight loss laboratory corrosion tests in hydrofluoric acid can be frustrating since the results are not as highly reproducible as in the case of other acids such as sulfuric or hydrochloric. One …

Environmentally Assisted Cracking (EAC) is a general term that includes phenomena such as stress corrosion cracking (SCC), hydrogen embrittlement (HE), sulfide stress cracking (SSC), liquid metal embrittlement (LME), etc. EAC refers to a phenomenon by which a normally ductile metal looses its toughness (e.g. elongation to rupture) when it is subjected to mechanical stresses in presence of a specific corroding environment. For EAC to occur, three affecting factors must be present simultaneously. These include: (1) Mechanical tensile stresses, (2) A susceptible metal microstructure and (3) A specific aggressive environment. If any of these three factors is removed, EAC will not occur. That is, to mitigate the occurrence of EAC, engineers may for example eliminate residual stresses in a component or limit its application to certain chemicals (environment). The term environment not only includes chemical composition of the solution in contact with the component but also other variables such as temperature and applied potential. Nickel alloys are in general more resistant than stainless steels to EAC. For example, austenitic stainless steels (such as S30400) suffer SCC in presence of hot aqueous solutions containing chloride ions. Since chloride ions are ubiquitous in most industrial applications, the use of stressed stainless steels parts …

Many applications in wireless communications often require short-range systems capable of rapidly collecting data and transmitting it reliably. Commercial communication systems operate in fixed frequency bands and are easily detectable and are prone to jamming by the enemy, among other shortcomings. The new ultra-wideband (UWB) communications system in the 3.1 to 10 GHz band is of significant interest to a number of Lawrence Livermore National Laboratory (LLNL) programs including the Nonproliferation, Arms Control, and International Security (NAI) Directorate. Ultra-Wideband (UWB) technology has received a significant degree of attention from communications industry since the Federal Communications Commission (FCC) rulings in February 2002. According to FCC, UWB signals have fractional bandwidth (B{sub f}) of 20% or larger at -10 dB cut-off frequencies, with minimum bandwidth of 500 MHz. Unlike traditional communication systems, UWB systems modulate carrier-less, short-duration (picosec to nanosec) pulses to transmit and receive information. A number of programmatic problems at LLNL, particularly in the NAI and other national security Directorates, require collecting information from multiple sensors distributed over a local area. The information must be collected covertly and by wireless means. The sensors produce data using low power devices and the communication link must operate in severe multipath environments over …

This is the final report for LDRD 01-ERD-005. The Principal Investigator was Niel Madsen of the Defense Sciences Engineering Division (DSED). Collaborators included Daniel White, Joe Koning and Nathan Champagne of DSED, Mark Stowell of Center for Applications Development and Software Engineering (CADSE), and Ph.D. students Rob Rieben and Aaron Fisher at the UC Davis Department of Applied Science. It should be noted that the students were partially supported by the LLNL Student-Employee Graduate Research Fellow program. We begin with an Introduction which provides background and motivation for this research effort. Section II contains high-level description of our Approach, and Section III summarizes our key research Accomplishments. A description of the Software deliverables is provided in Section IV, and Section V includes simulation Validation and Results. It should be noted we do not get into the mathematical details in this report, rather these can be found in our publications which are listed in Section III.