Metallic films are grown with a sponge-like morphology in the as-deposited condition using planar magnetron sputtering. The morphology of the deposit is characterized by metallic continuity in three dimensions with continuous porosity on the sub-micron scale. The stabilization of the metallic sponge is directly correlated with a limited range for the sputter deposition parameters of working gas pressure and substrate temperature. This sponge-like morphology augments the features as generally understood in the classic zone models of growth for physical vapor deposits. Nickel coatings are deposited with working gas pressures up to 4 Pa and for substrate temperatures up to 1100 K. The morphology of the deposits is examined in plan and in cross-section with scanning electron microscopy. The parametric range of gas pressure and substrate temperature (relative to absolute melt point) for the deposition processing under which the metallic sponges are produced appear universal for many metals, as for example, including gold, silver, and aluminum.

In filled PDMS based composites, such as M97XX stress cushions, significant mechanical reinforcement of the polymer component is obtained from hydrogen bonding between the silica filler surface hydroxyls and the siloxane polymer backbone. It is expected that these interactions are influenced by the amount and structure of interfacial water. We have chosen to investigate in detail the effect of chemisorbed and physisorbed water on the interfacial structure and dynamics in silica-filled PDMS-based composites. Toward this end, we have combined classical molecular dynamics simulations and experimental studies employing nanoindentation, temperature programmed desorption (TPD), Dynamic Mechanical Analysis (DMA), and Nuclear Magnetic Resonance (NMR) analyses. Our TPD results suggest that moisture desorption and adsorption in M9787 can be approximated by the interaction of its silica constituents (Cab-0-Sil-M-7D and Hi-Sil-233) with moisture. Our experimental data also reveal that, in general, as heat-treated silica particles are exposed to moisture, chemisorbed states, then physisorbed states are gradually filled up in that order. Molecular modeling results suggest that the polymer-silica contact distance and the mobility of interfacial polymer chains significantly decreased as the hydration level at the interface was reduced. The reduced mobility of the PDMS chains in the interfacial domain reduced the bulk motional properties of …

Various operations are authorized in Hanford single- and double-shell tanks that disturb all or a large fraction of the waste. These globally waste-disturbing activities have the potential to release a large fraction of the retained flammable gas and to affect future gas generation, retention, and release behavior. This report presents analyses of the expected flammable gas release mechanisms and the potential release rates and volumes resulting from these activities. The background of the flammable gas safety issue at Hanford is summarized, as is the current understanding of gas generation, retention, and release phenomena. Considerations for gas monitoring and assessment of the potential for changes in tank classification and steady-state flammability are given.

Lawrence Livermore National Laboratory (LLNL) has been actively and continuously engaged in Russian geologic disposal activities since 1995. The first joint US-Russian meeting on Disposition of Excess Weapons Plutonium was held in January 1995 at Los Alamos National Laboratory (LANL). The meeting resulted in the appointment of Dr. L. J. Jardine from LLNL and Dr. T. A. Gupalo from the All-Russian Research and Design Institute of Production Engineering (VNIPIPT) as the US-Russian Federation (RF) joint co-chairs for geologic disposal of plutonium-containing materials, respectively. The initial joint studies focused on the geologic disposal of plutonium-containing materials and immobilized plutonium waste forms. These studies started in 1995, and continue in 2002. The first joint work of LLNL and VNIPIPT was documented in the October 1996 Paris P8 Nuclear Experts Meeting [1]. In summary, LLNL has been actively and continuously involved in various ways since 1995 in developing and participating in the current Russian geologic disposal program activities near the Mayak and MCC K-26 sites. Figure 1 illustrates how these various LLNL activities have been integrated, coordinated, and focused on developing geologic disposal in Russia. The various LLNL contracts are shown in the figure with the specific LLNL contract number. Reference 13 provides …

Preliminary results already show that we collected enough statistics in this experiment to yield a meaningful spectral distribution of two-step {gamma}-ray transitions. Analysis of the data continues. We hope to soon be able to fill Fig. 5 with data points, favoring either the hypothesis of an electric pygmy resonance (red line) or orbital magnetic scissors mode (blue line).

We have investigated the flash of light that accompanies laser damage using time-resolved spectroscopy. Damage events were initiated in the bulk of DKDP and fused silica with 355-nm, 3-ns pulsed radiation. Spectra from the accompanying flash were recorded in the 200-500 nm wavelength range with 10-ns temporal resolution. Ten ns following damage initiation, the spectra were found to be roughly blackbody with temperatures on the order of 5000-7000 K. The observed temperatures and cooling rates can be related to the size and electron density of the plasma ''fireball'' that initiates the damage event.

The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at {radical}(s{sub NN}) = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/{bar p}p and e{sup +}e{sup -} data. <N{sub ch}>/<N{sub part}/2> in nuclear collisions at high energy scales with {radical}s in a similar way as N{sub ch} in e{sup +}e{sup -} collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

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The approach of isolating high-level nuclear waste in the designated site of Yucca Mountain (Nevada) is to separate it from the environment using a series of engineering and natural barriers. The container for the waste will consist of two concentric metal cylinders. The outer cylinder is going to be fabricated of Alloy 22 (N06022). If water is present at the site, several corrosion processes may occur. These include passive or general corrosion, localized corrosion and environmentally assisted cracking. The occurrence of one (or more) mode of corrosion over another will be determined by the redox potential of the aqueous electrolyte that may enter in contact with the container. This redox potential will also control the corrosion potential (E{sub corr}) of the container. This paper summarizes the findings of an extensive laboratory testing aimed at measuring E{sub corr} of Alloy 22 in presence of a variety of electrolyte solutions. Some of these solutions are multi-ionic electrolytes that may simulate concentrated ground waters. Other environments are chemical solutions of pure salts, which are highly unlikely for an underground repository but that may establish an extreme bounding condition. Current results show that the highest measured potential for Alloy 22 was approximately +0.3 to …

The NLC beam dump face is a thin copper plate. Energy deposition in the copper face has two sources--primary and secondary electromagnetic showers. Primary showers are those where the incoming beam particle initiates an electromagnetic cascade. Secondary showers are those that occur after a nuclear interaction of a beam particle with the copper. An upper limit for the nuclear transmutation rate is also estimated.

The intensity of the polarized Ly-{alpha}{sub 1} (2p{sub 3/2} {yields} 1s{sub 1/2}) transition has been measured relative to that of the unpolarized Ly-{alpha}{sub 2} (2p{sub 1/2} {yields} 1s{sub 1/2}) transition in Fe{sup 25+}. The measurements were made with the Livermore electron beam ion trap EBIT-II for beam energies from threshold to 2.5 times threshold. The results are compared to the corresponding intensity ratio predicted using excitation cross sections from distorted-wave calculations, which includes polarization, the M1(2s{sub 1/2} {yields} 1s{sub 1/2}) transition, and cascade contributions. Discrepancies are found that tend to confirm a recent report of a measurement of the Ly-{alpha} lines in Ti{sup 21+} performed on the Tokyo electron beam ion trap.

A scalable fiber laser approach is described based on phase-locking multiple gain cores in an antiguided structure. The waveguide is comprised of periodic sequences of gain- and no-gain-loaded segments having uniform index, within the cladding region. Initial experimental results are presented.

We offer a case for active technical management of the radiative forcing of the temperatures of the Earth's fluid envelopes, rather than administrative management of atmospheric greenhouse gas inputs, in order to stabilize both the global- and time-averaged climate and its mesoscale features. We suggest that active management of radiative forcing entails negligible--indeed, likely strongly negative--economic costs and environmental impacts, and thus best complies with the pertinent mandate of the UN Framework Convention on Climate Change. We propose that such approaches be swiftly evaluated in sub-scale in the course of an intensive international program.

The interaction of strong shock waves, such as those generated by the explosion of supernovae with interstellar clouds, is a problem of fundamental importance in understanding the evolution and the dynamics of the interstellar medium (ISM) as it is disrupted by shock waves. Here we present the results of a series of Nova laser experiments investigating the evolution of a high density sphere embedded in a low density medium after the passage of a strong shock wave, thereby emulating the supernova shock-cloud interaction. The Nova laser was utilized to generate a strong ({approx}Mach 10) shock wave that traveled along a miniature beryllium shock tube, 750 {micro}m in diameter, filled with a low-density plastic emulating the ISM. Embedded in the plastic was a copper microsphere (100 {micro}m in diameter) emulating the interstellar cloud. The morphology and evolution as well as the shock wave trajectory were diagnosed via side-on X-ray radiography.

We have developed equipment and technology for fabricating submicron pitch, high-efficiency diffraction gratings over meter-scale apertures that are used for pulse compression in ultrafast systems around the world. We have also developed wet-etch figuring (WEF) to generate arbitrary continuous contours on ultrathin glass substrates in a closed loop process. The current and future states of these technologies will be discussed.

Generation of surface meshes is the first step in many grid generation processes. For the generation of block-structured meshes, structured surface meshes have to be generated first. This paper investigates the problem of generating a structured surface mesh across multiple surface patches on an object with the boundary representation and relates the problem to other commonly encountered issues in CAD/CAM. It describes a method for solving the problem. This method is based on initial surface construction, point projection and a mixed model-space and parameter-space based elliptic smoothing.

In the Nd-Fe-A1 system, compositions in the range of Nd{sub 60}Fe{sub 30}Al{sub 10} have been reported to be ferromagnetic bulk metallic glasses with high coercivities. Careful examination of both the microstructure and magnetic properties of these materials shows this to be true only in the most general sense. The materials are shown to be nanocomposites, in the strictest sense, with characteristic structural length scales on the order of 1.2 nm. Magnetically, the materials are also composites exhibiting a number of magnetic transitions as a function of temperature. The temperature dependence of the magnetic properties will be discussed in terms of strongly-interacting superparamagnetic clusters residing in a paramagnetic matrix. The clusters exhibit a frequency-dependent blocking temperature as determined from AC susceptibility, that is inconsistent with simple superparamagnetic behavior but is consistent with a spin glass-type ordering of the clusters to form a cluster glass. For a temperature region extending approximately 100 K below the cluster glass ordering temperature, the materials exhibit low coercivity. Below this temperature regime significant coercivities develop. The energy barrier to magnetic reversal provided by the product of the cluster volume multiplied by the anisotropy energy is inconsistent with the values required to fit the superparamagnetic behavior above …

This report represents Phase I of a multi-phase approach to a source investigation of DDT at the Heckathorn Superfund Site, Richmond, California, the former site of a pesticide packaging plant, and the adjacent waterway, the Lauritzen Channel. Potential identified sources of contamination were from sloughed material from undredged areas (such as side banks) and from outfall pipes. Objectives of Phase I included the (1) evaluation of pesticide concentrations associated with discharge from outfalls, (2) identification of additional outfalls in the area, (3) identification of type, quantity, and distribution of sediment under the Levin pier, (4) quantification of pesticide concentrations in sediment under the pier, and (5) evaluation of sediment structure and slope stability under the pier. Field operations included the collection of sediment directly from inside the mouths of outfall pipes, when possible, or the deployment of specially designed particle traps where direct sampling was problematic. Passive water samplers were placed at the end of known outfall pipes and analyzed for DDT and other pesticides of concern. Underwater dive surveys were conducted beneath the Levin pier to document type, slope, and thickness of sediment. Samples were collected at locations of interest and analyzed for contaminants. Also sampled was soil from …

We present a surface compression method that stores surfaces as wavelet-compressed signed-distance volumes. Our approach enables the representation of surfaces with complex topology and arbitrary numbers of components within a single multiresolution data structure. This data structure elegantly handles topological modification at high compression rates. Our method does not require the costly and sometimes infeasible base mesh construction step required by subdivision surface approaches. We present several improvements over previous attempts at compressing signed-distance functions, including an 0(n) distance transform, a zero set initialization method for triangle meshes, and a specialized thresholding algorithm. We demonstrate the potential of sampled distance volumes for surface compression and progressive reconstruction for complex high genus surfaces.

Electrical resistance measurements were used to monitor several releases of brine from the Mock Tank Test site at the 200 East Area. Three different methods were used to analyze the data: (1) a simple average of the raw data was used as an indicator of the presence/absence of a leak, (2) tomography of the region beneath the tank using data from steel-cased borehole, and (3) tomography of the region beneath the tank using data from vertical electrode arrays. Each of these methods was able to detect the presence of what appeared to be conductive plumes forming beneath the tank. The results suggest the following: (1) The minimum detectable leak volume is of the Order of a few hundred gallons. (2) procedure involving the use of reciprocal data can be used to evaluate the reliability of the results and minimize the potential for false-positive and false-negative conclusions; (3) The dry wells may be used as long electrodes to obtain 2D images of the plume under the tank. (4) 3D electrical resistance tomography (ERT) images provide information that can be used to determine the released volume, the speed and direction of plume movement, the regions of the soil that are being contaminated, …

I thought it was important to relate how this project began. Jens Mahler, Mechanical Engineering Deputy Associate Director, recalls that during a discussion between him and Wally Decker, Wally suggested that he document the significant events and the organization of the Mechanical Engineering Department since 1952, i.e., write a history of Mechanical Engineering. Jens agreed that Wally should begin this effort. Upon learning of this, Dave Pehrson, Deputy Associate Director for Engineering, suggested that the History be expanded to include Electronics Engineering and that it be called A History of Engineering. Dave asked me to join Wally on this effort and, unfortunately, Wally died shortly after I started. In the first part of this History, I have attempted to capture the important contributions that Engineering has made to the Programs, since Engineering's primary mission is to provide ''support to the Laboratory Programs.'' In the later parts you will find views discussing the development and application of Engineering's technology base. While Engineering's direct programmatic support had first priority, Engineering had other responsibilities as well. Some of these were to hire and train a competent technical and leadership staff, to anticipate and develop engineering technologies for future use by the Programs, to …

A solid-state high voltage pulse generator with multi-pulse burst capability, very fast rise and fall times, pulse width agility, and amplitude modulation capability for use with high speed electron beam kickers has been designed and tested at LLNL. A control system calculates a desired waveform to be applied to the kicker based on measured electron beam displacement then adjusts the pulse generators to provide the desired waveform. This paper presents the design of the control system and measure performance data from operation on the ETA-11 accelerator at LLNL.

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