Advanced, coal-based power plants will require durable and reliable hot gas filtration systems to remove particulate contaminants from the gas streams to protect downstream components such as turbine blades from erosion damage. It is expected that the filter elements in these systems will have to be made of ceramic materials to withstand goal service temperatures of 1600 F or higher. Recent demonstration projects and pilot plant tests have indicated that the current generation of ceramic hot gas filters (cross-flow and candle configurations) are failing prematurely. Two of the most promising materials that have been extensively evaluated are clay-bonded silicon carbide and alumina-mullite porous monoliths. These candidates, however, have been found to suffer progressive thermal shock fatigue damage, as a result of rapid cooling/heating cycles. Such temperature changes occur when the hot filters are back-pulsed with cooler gas to clean them, or in process upset conditions, where even larger gas temperature changes may occur quickly and unpredictably. In addition, the clay-bonded silicon carbide materials are susceptible to chemical attack of the glassy binder phase that holds the SiC particles together, resulting in softening, strength loss, creep, and eventual failure.

Nitric acid solutions will be created from the dissolution of Hanford K Basin sludge. These acidic dissolver solutions must be made alkaline by treatment with NaOH solution before they are disposed to ~ the Tank Waste Remediation System on the Hanford Site. During the alkali treatments, sodium diuranate, hydroxides of iron and aluminum, and radioelements (uranium, plutonium, and americium) will precipitate from the dissolver solution. Laboratory tests, discussed here, were pefiormed to provide information on these precipitates and their precipitation behavior that is important in designing the engineering flowsheet for the treatment process. Specifically, experiments were conducted to determine the optimum precipitation conditions; the completeness of uranium, plutonium, and americium precipitation; the rate of sedimentation; and the physico-chemical characteristics of the solids formed by alkali treatment of simulated acidic dissolver solutions. These experiments also determined the redistribution of uranium, plutonium, and americium flom the sodium di~ate and iron and al&inurn hydroxide precipitates upon contact with carbonate- and EDTA-bearing simulated waste solutions. Note: EDTA is the tetrasodium salt of ethylenediaminetetraacetate.

Seismic monitoring at the Hanford Site was established in 1969 by the United States Geological Survey (USGS) under a contract with theJ.J.S. Atomic Energy Commission. In 1975, the University of Washington (UW) assumed responsibility for the network and subsequently expanded it. In 1979, the Basalt Waste o Isolation Program (13WIP) became responsible for collecting seismic data for the Hdord Site as part of site " characterization activities. Rockwell Htiord Operations, followed by Westinghouse Ha&ord Company . (WHC), operated the local network and were the contract technical advisors for the Eastern Washington Regional Network @wRN) operated and maintained by the UW. Funding for BWIP ended in December 1988. Seismic Monitoring and responsibility for the University of Washington contract were then trans- ferred to WHC'S Environmental Division. Maintenance responsibilities for the EWRN were also Assigned to WHC, who made major upgrades to EWRN sites. Effective October 1,1996, Seismic Monitoring was transfemed to the Pacific Northwest National Laboratory (PI@lL*). Seismic Monitoring is part of PNNL's Applied Geology and Geochemistry Group, Energy Technology Division. The Hanford Strong Motion Accelerometer network was constructed during 1997 and came online in May 1997. It operated continuously until September 30, 1997, when it was mothballed due to can- …

The Laser Program at LLNL has developed automated facilities for damage testing optics up to 1 meter in diameter. The systems were developed to characterize the statistical distribution of localized damage performance across large-aperture National Ignition Facility optics. Full aperture testing is a key component of the quality assurance program for several of the optical components. The primary damage testing methods used are R:1 mapping and raster scanning. Automation of these test methods was required to meet the optics manufacturing schedule. The automated activities include control and diagnosis of the damage-test laser beam as well as detection and characterization of damage events.

An attempt is made to identify preferred values for the work functions of the rare earth elements by correlating the atomic chemical potential with the work function of the bulk elements. Trends in the alkali and alkali earth metal are evaluated in the same context. Strong linear correlation between the two quantities is observed within the IA, 11A, and IIIB (Se, Y, La) groups. Within the lanthanide series the nature of the correlation between the metallic radius and the work function suggests a dependence on the total angular momentum.

A reliable metric is required to describe the damage resistance of large aperture 3{omega} transmissive optics for the National Ignition Facility (NIF) laser. The trend from single site testing to the more statistically valid Gaussian scanning test requires a well modeled experimental procedure, accurate monitoring of the test parameters, and careful interpretation of the resulting volumes of data. The methods described here provide reliable quality assurance data, as well as intrinsic damage concentration information used to predict the performance expected under use conditions. This paper describes the equipment, test procedure, and data analysis used to evaluate large aperture 3{omega} optics for the NIF laser.

Laser-induced damage of transparent fused silica optical components by 355 nm illumination occurs primarily at surface defects produced during the grinding and polishing processes. These defects can either be surface defects or sub-surface damage.Wet etch processing in a buffered hydrogen fluoride (HF) solution has been examined as a tool for characterizing such defects. A study was conducted to understand the effects of etch depth on the damage threshold of fused silica substrates. The study used a 355 nm, 7.5 ns, 10 Hz Nd:YAG laser to damage test fused silica optics through various wet etch processing steps. Inspection of the surface quality was performed with Nomarski microscopy and Total Internal Reflection Microscopy. The damage test data and inspection results were correlated with polishing process specifics. The results show that a wet etch exposes subsurface damage while maintaining or improving the laser damage performance. The benefits of a wet etch must be evaluated for each polishing process.

Advanced rechargeable lithium-ion batteries are presently being developed and commercialized worldwide for use in consumer electronics, military and space applications. At Sandia National Laboratories we have used different electrochemical techniques such as impedance and charge/discharge at ambient and subambient temperatures to probe the various electrochemical processes that are occurring in Li-ion cell. The purpose of this study is to identify the component that reduces the cell performance at subambient temperatures. Our impedance data suggest that while the variation in the electrolyte resistance between room temperature and {minus}20 C is negligible the anode electrolyte interfacial resistance increases by an order of magnitude in the same temperature regime. We believe that the solid electrolyte interface (SEI) layer on the carbon anode may be responsible for the increase in cell impedance. We have also evaluated the cells in hybrid mode with capacitors. High-current operation in the hybrid mode allowed fill usage of the Li-ion cell capacity at 25 C and showed a factor of 5 improvement in delivered capacity at {minus}20 C.

For the aggressive fluence requirements of the NIF laser, some level of laser-induced damage to the large (40 x 40 cm) 351 nm final optics is inevitable. Planning and utilization of NIF therefore requires reliable prediction of the functional degradation of the final optics. Laser damage tests are typically carried out with Gaussian beams on relatively small test areas. The tests yield a damage probability vs energy fluence relation. These damage probabilities are shown to depend on both the beam fluence distribution and the size of area tested. Thus, some analysis is necessary in order to use these test results to determine expected damage levels for large aperture optics. The authors present a statistical approach which interprets the damage probability in terms of an underlying intrinsic surface density of damaging defects. This allows extrapolation of test results to different sized areas and different beam shapes (NIF has a flattop beam). The defect density is found to vary as a power of the fluence (Weibull distribution).

First principles calculations using the local-spin-density-functional theory are presented of densities of electronic states for MnO, LiMnO{sub 2} in the monoclinic and orthorhombic structures, cubic LiMn{sub 2}O{sub 4} spinel, and {lambda}-MnO{sub 2} (delithiated spinel), all in antiferromagnetic spin configurations. The changes in energy spectra as the Mn oxidation state varies between 2+ and 4+ are illustrated. Preliminary calculations for Co-doped LiMnO{sub 2} are presented, and the destabilization of a monoclinic relative to a rhombohedral structure is discussed.

This guide provides information in support of the National Clean Cities Program, which will assist one in becoming better informed about the choices and options surrounding the use of alternative fuels and the purchase of alternative fuel vehicles. The information printed in this guide is current as of September 15, 1998. For recent additions or more up-to-date information, check the Alternative Fuels Data Center Web site at http://www.afdc.doe.gov

A cryogenic pumping system is provided, comprising a vacuum environment, an aerogel sorbent formed from a carbon aerogel disposed within the vacuum environment, and cooling means for cooling the aerogel sorbent sufficiently to adsorb molecules from the vacuum environment onto the aerogel sorbent. Embodiments of the invention include a liquid refrigerant cryosorption pump, a compressed helium cryogenic pump, a cryopanel and a Meissner coil, each of which uses carbon aerogel as a sorbent material.

A statistics-based model is being developed to predict the laser-damage-limited lifetime of UV optical components on the NIF laser. In order to provide data for the model, laser damage experiments were performed on the Beamlet laser system at LLNL (aperture: 34 cm x 34 cm). Three prototype NIF focus lenses were exposed to 351 nm pulses (1.5 ns or 3 ns) during four experimental campaigns, each consisting of 23 to 38 pulses at NIF relevant fluences. Each lens was sol-gel AR coated and all laser exposures were performed in a vacuum environment. Through inspections of the lens before, during and after the campaigns, pulse-to-pulse damage growth rates were measured for damage initiating both on the surfaces and at bulk inclusions. Radial growth rates measured for rear surface damage was typically 10x higher than that measured in the bulk or at the front surface. No significant correlation of growth rate to precursor type was indicated. For 5 J/cm², 3 ns pulses the typical radial growth rate was nominally 20 µm/pulse. Average growth rates measured on three lenses made by two manufacturers were in good agreement. While the growth rate clearly increased with fluence, the data obtained was insufficient to quantify the …

None

This work combines focused ion beam sputtering and ultra-precision machining for microfabrication of metal alloys and polymers. Specifically, micro-end mills are made by Ga ion beam sputtering of a cylindrical tool shank. Using an ion energy of 20keV, the focused beam defines the tool cutting edges that have submicrometer radii of curvature. We demonstrate 25 {micro}m diameter micromilling tools having 2, 4 and 5 cutting edges. These tools fabricate fine channels, 26-28 microns wide, in 6061 aluminum, brass, and polymethyl methacrylate. Micro-tools are structurally robust and operate for more than 5 hours without fracture.

Removal and immobilization of mercury ions from industrial waste streams is a difficult and expensive problem requiring an efficient and selective extractant that is resistant to corrosive conditions. We have now developed an acid-resistant thiacrown polymer that has potential utility as a selective and cost-effective Hg²⁺ extractant. Copolymerization of a novel C-substituted thiacrown, N,N-(4-vinylbenzylmethyl)-2-aminomethyl- ,4,&l 1,14- pentathiacycloheptadecane, with DVB (80% divinylbenzene) using a radical initiator generated a highly cross-linked polymer containing pendant thiacrowns. Mercury extraction capabilities of the polymer were tested in acidic media (pH range: 1.5 to 6.2) and the extraction of Hg²⁺ was determined to be 95⁺% with a mixing time of 30 minutes. The thiacrown polymer was also determined to be selective for Hg*+, competing ions such as Pb²⁺, Cd²⁺, A1³⁺, and Fe³⁺. even in the presence of high concentrations of The bound Hg²⁺ ions can then be stripped from the polymer, allowing the polymer to be reused without significant loss of loading capacity.

Why Hand Waving? All calculations in books describe oscillations in time. But real experiments don't measure time. Hand waving is used to convert the results of a ''gedanken time experiment'' to the result of a real experiment measuring oscillations in space. Right hand waving gives the right answer; wrong hand waving gives the wrong answer. Many papers use wrong handwaving to get wrong answers. This talk explains how to do it right and also answers the following questions: (1) A neutrino which is a mixture of two mass eigenstates is emitted with muon in the decay of a pion at rest. This is a ''missing mass experiment'' where the muon energy determines the neutrino mass. Why are the two mass states coherent? (2) A neutrino which is a mixture of two mass eigenstates is emitted at time t=0. The two mass eigenstates move with different velocities and arrive at the detector at different times. Why are the two mass states coherent? (3) A neutrino is a mixture of two overlapping wave packets with different masses moving with different velocities. Will the wave packets eventually separate? If yes, when?

Silver/glass mirrors have excellent optical properties but need a method of support in order to be used in concentrating solar thermal systems. In collaboration with the Cummins dish/Stirling development program, they started investigating sandwich construction as a way to integrate silver/glass mirrors into solar optical elements. In sandwich construction, membranes such as sheet metal or plastic are bonded to the front and back of a core (like a sandwich). For solar optical elements, a glass mirror is bonded to one of the membranes. This type of construction has the advantages of a high strength-to-weight ratio, and reasonable material and manufacturing cost. The inherent stiffness of sandwich construction mirror panels also facilitates large panels. This can have cost advantages for both the amount of hardware required as well as reduced installation and alignment costs. In addition, by incorporating the panels into the support structure reductions in the amount of structural support required are potentially possible.

A novel photothermal microscopy (PTM) is developed which uses only one laser beam, working as both the pump and the probe. The principle of this single-beam PTM is based on the detection of the second harmonic component of the laser modulated scattering (LMS) signal. This component has a linear dependence on the optical absorptance of the tested area and a quadratic dependence on the pump laser power. Using a pump laser at the wavelengths of 514.5- and 532-nm high-resolution photothermal scans are performed for polished fused silica surfaces and a HfO{sub 2}/SiO{sub 2} multilayer coatings. The results are compared with those from the traditional two-beam PTM mapping. It is demonstrated that the single-beam PTM is more user-friendly (i.e. no alignment is needed) than conventional two-beam PTM and, offers a higher spatial resolution for defect detection.

TART98 is a coupled neutron-photon, 3 Dimensional, combinatorial geometry, time dependent Monte Carlo radiation transport code. This code can run on any modern computer. It is a complete system to assist you with input preparation, running Monte Carlo calculations, and analysis of output results. TART98 is also incredibly FAST; if you have used similar codes, you will be amazed at how fast this code is compared to other similar codes. Use of the entire system can save you a great deal of time and energy. TART98 is distributed on CD. This CD contains on-line documentation for all codes included in the system, the codes configured to run on a variety of computers, and many example problems that you can use to familiarize yourself with the system. TART98 completely supersedes all older versions of TART, and it is strongly recommended that users only use the most recent version of TART98 and its data files.

No abstract is available for this document at this time.

Storage rings and Penning traps are being used to study ions in their highest charge states. Both devices must have the capability for ion cooling in order to perform high precision measurements such as mass spectrometry and laser spectroscopy. This is accomplished in storage rings in a merged beam arrangement where a cold electron beam moves at the speed of the ions. In RETRAP, a Penning trap located at Lawrence Livermore National Laboratory, a sympathetic laser/ion cooling scheme has been implemented. In a first step, singly charged beryllium ions are cooled electronically by a tuned circuit and optically by a laser. Then hot, highly charged ions are merged into the cold Be plasma. By collisions, their kinetic energy is reduced to the temperature of the Be plasma. First experiments indicate that the highly charged ions form a strongly coupled plasma with a Coulomb coupling parameter.

Aluminum (Al) is a commonly used matrix for research reactor fuel plates. It has been found that a reaction between the fuel and the aluminum matrix may reduce or increase the irradiation stability of the fuel. To further understand the contribution of the reaction to the irradiation stability, experiments to develop a non-reacting matrix were performed. The work focused on magnesium (Mg), which is an excellent non-reacting matrix candidate and has a neutron absorption coefficient similar to Al. To avoid the formation of a liquid Al/Mg phase, improvements were made to the roll bonding process to achieve acceptable bonding at 415 C. After these methods were developed, fuel plates were produced with two fuels, uranium (U)-2 w/o molybdenum (Mo) and U-10-w/o Mo with two matrices, Al and Mg. A reaction between the magnesium and the 6061 Al cladding was discovered to take place during the processing at 415 C. To minimize the amount of reaction, methods were successfully developed to roll bond the fuel plates at 275 C. No reaction zone was observed in fuel plates processed at 275 C. Using this method, fuel plates with a Mg matrix are planned to be fabricated and included in the next irradiation …

Different concentrations of Na were systematically introduced into CuInSe2 (CIS) photovoltaic solar cell absorber material on different substrates (SLG, Si02/SLG, 7059, alumina) to: (1) determine the resultant effects on device properties, junction formation, and material microstructure; and (2) determine the optimal range of Na concentrations in the CIS films per specific substrate. In general, finished devices show improved Voc, Jsc, and device efficiency, improved charge-collection efficiency and, possibly, increased grain size as a result of the coevaporation of 4 to 100 mg of Na2Se during film deposition. However, a dramatic devolution set in with the addition of 235 mg of Na2Se, and all the aforementioned parameters were either at, or worse than, their pre-Na-addition levels. Meanwhile, although the device microstructure improves with Na addition and, more importantly, the junction (as characterized by electron-beam-induced current) has become much more uniform and closer to the heteroface, all that reverses with the ''Na overdose.''