Publications

More than 300 sinkholes, fissures, depressions, and other collapse features occur along a 70 km (45 mi) dissolution front of the Permian Supai Formation, dipping northward into the Holbrook Basin, also called the Supai Salt Basin. The dissolution front is essentially coincident with the so-called Holbrook Anticline showing local dip reversal; rather than being of tectonic origin, this feature is likely a subsidence-induced monoclinal flexure caused by the northward migrating dissolution front. Three major areas are identified with distinctive attributes: (1) The Sinks, 10 km WNW of Snowflake, containing some 200 sinkholes up to 200 m diameter and 50 m depth, and joint controlled fissures and fissure-sinks; (2) Dry Lake Valley and contiguous areas containing large collapse fissures and sinkholes in jointed Coconino sandstone, some of which drained more than 50 acre-feet ({approximately}6 {times} 10{sup 4} m{sup 3}) of water overnight; and (3) the McCauley Sinks, a localized group of about 40 sinkholes 15 km SE of Winslow along Chevelon Creek, some showing essentially rectangular jointing in the surficial Coconino Formation. Similar salt karst features also occur between these three major areas. The range of features in Supai salt are distinctive, yet similar to those in other evaporate basins. The wide variety of dissolution/collapse features range in development from incipient surface expression to mature and old age. The features began forming at least by Pliocene time and continue to the present, with recent changes reportedly observed and verified on airphotos with 20 year repetition. The evaporate sequence along interstate transportation routes creates a strategic location for underground LPG storage in leached caverns. The existing 11 cavern field at Adamana is safely located about 25 miles away from the dissolution front, but further expansion initiatives will require thorough engineering evaluation.

We performed neutron powder diffraction on solution-derived lead zirconate titanates (PZT). Three compositions, PZT 45/55, PZT 20/80 and PbTiO{sub 3}, were investigated. The materials were annealed so that the perovskite phase had just begun to grow from the precursor phase. In our materials this precursor phase is the pyrochlore rather than fluorite phase. The results show that in the pyrochlore phase, the (Ti,Zr) and the Pb are ordered in their crystallographic sites while the O are essentially disordered in both of the two usual pyrochlore anion sites.

A conversion coating method has been developed based on precipitation of Li{sub 2}[Al{sub 2}(OH){sub 6}]{sub 2}{center_dot}CO{sub 3}{center_dot}3H{sub 2}O from alkaline lithium salt solutions. The process is procedurally similar to chromate conversion coating but does not use or produce hazardous chemicals. The coating that forms is polycrystalline, continuous and conformal. The coating meets the MIL-C-5541E corrosion resistance, electrical contact resistance and paint adhesion requirements for certain aluminum alloys, but does not match the levels of performance exhibited by chromate conversion coatings. In this paper, methods for producing the coating are described. Corrosion resistance has been characterized using electrochemical impedance spectroscopy and salt spray exposure. The structural, compositional and property changes attending post-coating thermal exposure are discussed. Performance in standardized corrosion, electrical and paint adhesion tests is also presented.

Hexylene-bridged polysilsesquioxanes can be prepared as mesoporous or non-porous xerogels simply by switching from basic to acidic polymerization conditions. In this study, we looked at the effect of monomer concentration on porosity of hexylene-bridged xerogels prepared under acidic and basic conditions. 1, 6-Hexylene-bridged polysilsesquioxanes were prepared by sol-gel polymerizations of 1, 6-bis(triethoxysilyl)hexane 1 with concentrations between 0. 1 to 1.2 M in ethanol. Gelation times ranged from seconds for 1.2 M concentration to months for 0.2 M. The gels were processed into xerogels by an aqueous work-up and the dry gels characterized by scanning electron microscopy (SEM), solid state {sup 13}C and {sup 29}Si CP MAS NMR spectroscopy, and gas sorption porosimetry.

Hydrocarbon-bridged polysilsesquioxanes are prepared by the sol-gel polymerization of monomers with more than one trialkoxysilyl group attached directly to the bridging group by Si-C bonds. While the effects of varying the identity of the bridging group (length, rigidity, etc.), monomer concentration, and type of catalyst have been studied, the effect of different alkoxy ligands on the silicon atoms has not been investigated. For this study, 1, 6-- bis(triethoxysilyl)hexane 1 and 1, 6-bis(trimethoxysilyl)hexane 2 were polymerized under acidic and basic conditions in ethanol and methanol, respectively, and in tetrahydrofuran (THF). The resulting gels were processed to afford xerogels that were characterized by SEM, solid state {sup 13}C and {sup 29}Si Cross Polarization Magic Angle Spinning (CP MAS) NMR spectroscopy, and nitrogen sorption porosimetry.

The flat panel display development activities underway at Sandia National Laboratories are described. Research is being conducted in the areas of glass substrates, phosphors, large area processes, and electron emissions. Projects are focused on improving process yield, developing large area processes, and using modeling techniques to predict design performance.

Optical prossesses in nanostructured fractal composites are shown to be strongly enhanced. The enhancement occurs because of a localization of dipolar eigenmodes in subwavelength areas.

I{sub DDQ} testing of CMOSICs is a technique for production quality and reliability improvement, design validation, and failure analysis. The origin and basic concepts of I{sub DDQ} testing are reviewed. The relationship of I{sub DDQ} testing to other test methods is considered in the context of the whole IC life cycle from design, fabrication, and test through end use. A comprehensive test strategy is described that uses defect classes based on defect electrical properties rather than traditional fault models.

Despite intensive efforts in the area of dynamic graph algorithms, no efficient algorithms are known for the dynamic versions of some basic graph problems such as strong connectivity and transitive closure. We provide some explanation for this lack of success by presenting quadratic lower bounds on the strong certificate complexity of such problems, thereby establishing the inapplicability of the only known general technique for designing dynamic graph algorithms, viz., sparsification. These results also provide evidence of the inherent intractability of such dynamic graph problems. Some of our results are based on a general technique for obtaining lower bounds on the strong certificate complexity for a class of graph properties by establishing a relationship with the witness complexity. In many real applications of dynamic graph problems, a certain amount of lookahead is available. Specifically, we consider the problems of assembly planning in robotics and the maintenance of relations in databases which, respectively, give rise to dynamic strong connectivity and transitive closure. We exploit the (naturally available) lookahead in these two applications to circumvent the inherent complexity of the dynamic graph problems. We propose a variant of sparsification, viz., lookahead based sparsification, and apply it to obtain the first efficient fully dynamic algorithms for strong connectivity and transitive closure.

The photo-destruction of the high explosives HMX, RDX and TNT was investigated using two systems (ozone versus titanium dioxide), two reactors (pot vs annular reactor), and two types of lamps (1000 Watt Hg-Xe vs 25 Watt LP Hg). A mass balance was performed on reactions executed under pseudo-solar conditions, and relative reaction rates and products were compared for ozone and titanium dioxide based processes. The ratios of relative product formation is also discussed. Results show that there was little difference in the reactions performed in the annular reactor when either ozone or titanium oxide were used. The chemistry of RDX and HMX are very similar, as expected. Future work involving the mechanism is also discussed.

Be is a ``marginal metal.`` The stable phase, hcp-Be, has a low Fermi-level density of states and very anisotropic structural and elastic properties, similar to a semiconductor`s. At the Be(0001) surface, surface states drastically increase the Fermi-level density of states. The different nature of bonding in bulk-Be and at the Be(0001) surface explains the large outward relaxation. The presence of surface states causes large surface core-level shifts by inducing a higher electrostatic potential in the surface layers and by improving the screening at the surface. The authors experimental and theoretical investigations of atomic vibrations at the Be(0001) surface demonstrate clearly that Be screening of atomic motion by the surface states makes the surface phonon dispersion fundamentally different from that of the bulk. Properties of Be(0001) are so different from those of the bulk that the surface can be considered a new ``phase`` of beryllium with unique electronic and structural characteristics. For comparison they also study Be(11{bar 2}0), a very open surface without important surface states. Be(11{bar 2}0) is the only clean s-p metal surface known to reconstruct (1 {times} 3 missing row reconstruction).

NMR and neutron diffraction measurements reveal that macroscopic phase separation and the tetragonal to orthorhombic (TO) structural phase coincide at two distinct points in the temperature-doping phase plot for oxygen doped La{sub 2}CuO{sub 4+{delta}}. Thus the TO phase line coincides with the phase separation line. This is evidence that the macroscopic phase separation is inhibited in the tetragonal phase. We propose that the interstitial oxygen has higher mobility in the orthorhombic phase and that insufficient mobility suppresses macroscopic phase separation in the tetragonal phase. Neutron diffraction measurements also reveal superlattice peaks which indicate ordering of the interstitial oxygen. Our NMR measurements, have demonstrated a distribution of tilts of the CuO{sub 6} octahedra. We propose a sawtooth modulation of the octahedral tilt in which the sign of the tilt changes when the tilt reaches a maximum value can explain this distribution. The large openings in the La-O layer resulting from the abrupt switch of the sign of the tilt provide an attractive location for the interstitial oxygen. This mechanism would lead to stripe ordering of the interstitial oxygen.

The microstructure of Al/{alpha}-Al{sub 2}0{sub 3} composites made by infiltrating Al into dense mullite preforms has been characterized using transmission electron microscopy. Observations revealed that the formation of the Al/Al{sub 2}0{sub 3} composites involves three stages. Initially, Al infiltrates into a dense mullite preform through grain boundary diffusion, and reacts with mullite at grain boundaries to form a partial reaction zone. Then, a complete reaction takes place in the reaction region between the partial reaction zone and the full reaction zone to convert the dense mullite preform to a composite of {alpha}-Al{sub 2}0{sub 3} (matrix) and an Al-Si phase (thin channels). Finally, the reduced Si from the reaction diffuses out of the Al/Al{sub 2}0{sub 3} composite through the metal channels, whereas Al from the molten Al pool is continuously drawn to the reaction region until the mullite preform is consumed or the sample is removed from the molten Al pool. Based on the observed microstructure, infiltration mechanisms have been discussed, and a growth model of the composites is proposed in which the process involves repeated nucleation of Al{sub 2}0{sub 3} grains and grain growth.

Copper chemical vapor deposition using liquid coinjection of the Cu(I) precursor (hfac)Cu(TMVS) along with TMVS has been demonstrated. The coinjection of TMVS with (hfac)Cu(TMVS) stabilizes the Cu precursor until it enters the reaction chamber, allowing for better control of the deposition and faster deposition rates. Using this technique, we have grown films with as-deposited resistivities of 1.86 {plus_minus} 0.04 {mu}{Omega}-cm, independent of film thickness. Deposition rates of well over 100 nm/min are possible. Good step coverage and gap fill down to 0.6 {mu}m lines is demonstrated, with gap fill being limited by the large Cu grain sizes in these films.

Very highly porous (aerogel) silica films with refractive index in the range 1.006--1.05 (equivalent porosity 98.5--88%) were prepared by an ambient-pressure process. It was shown earlier using in situ ellipsometric imaging that the high porosity of these films was mainly attributable to the dilation or `springback` of the film during the final stage of drying. This finding was irrefutably reconfirmed by visually observing a `springback` of >500% using environmental scanning electron microscopy (ESEM). Ellipsometry and ESEM also established the near cent per cent reversibility of aerogel film deformation during solvent intake and drying. Film thickness profile measurements (near the drying line) for the aerogel, xerogel and pure solvent cases are presented from imaging ellipsometry. The thickness of these films (crack-free) were controlled in the range 0.1-3.5 {mu}m independent of refractive index.

The pore size r{sub p} in a gel is determined by the extent of shrinkage of the gel network during drying. Shrinkage is driven by the collapse of the gel network in response to the capillary pressure P{sub c} exerted by the pore fluid. The extent of shrinkage depends on the balance between the capillary pressure P{sub c} in the pore fluid and the bulk modulus K{sub p} of the gel. The hydraulic pore radius, r{sub H} = 2V{sub p}/S{sub a}, where V{sub p} is the pore volume and S{sub a} is the apparent N{sub 2} BET surface area, is often used to characterize the pore size of a gel. A series of acid catalyzed silica gels dried in pore fluids with different {gamma}{sub lv}, showed that there is a limit to the minimum apparent r{sub H} obtainable in a gel, and when the volume fraction of porosity {phi} {le} 0.37, r{sub H} becomes constant and {approximately}0.8 nm. In contrast, experimental data show that the true pore size r{sub p} of gels continues to decrease when {phi} {le} 0.37. Analysis of their adsorption isotherms show that while r{sub H} apparently stays constant: (a) the BET C constant continues to increase, (b) the width and average of their pore size distributions continue to decrease, and (c) as shrinkage continues the gels eventually become non-porous to N{sub 2} at 77K but are still porous to CO{sub 2} at 273K. This paper reviews these results and addresses micropore formation in silica gels with the goal of determining how P{sub c} influences the final r{sub p}, and why r{sub p} and r{sub H} diverge when {phi} {le} 0.37.

A computational/analytical technique has been developed which models the physics of high pressure gas atomization. The technique uses an uncoupled approach, such that the gas flowfield is initially calculated with a commercially-available Navier-Stokes code. The liquid metal droplet breakup, dynamics, and thermodynamics, are then calculated using the pre-computed flowfield by a separate computer program written by the authors. The atomization code models the primary breakup of the liquid metal stream, tracks the droplets resulting from primary breakup through the flowfield until they undergo secondary breakup, and then tracks the subdroplets until they breakup, solidify, or leave the flowfield region of interest. The statistical properties of the metal powder produced are then computed from the characteristics of these droplets. Comparisons between experimental measurements and computations indicate that the Navier-Stokes code is predicting the gas flowfield well, and that the atomization code is properly modeling the physics of the droplet dynamics and breakup.

Modern wind turbines are fatigue critical machines used to produce electrical power. To insure long term, reliable operation, their structure must be optimized if they are to be economically viable. The fatigue and reliability projects in Sandia`s Wind Energy Program are developing the analysis tools required to accomplish these design requirements. The first section of the paper formulates the fatigue analysis of a wind turbine using a cumulative damage technique. The second section uses reliability analysis for quantifying the uncertainties and the inherent randomness associated with turbine performance and the prediction of service lifetimes. Both research areas are highlighted with typical results.

This report contains research in the following areas related to beam transport for a common ion driver: multi-gap acceleration; neutralization with electrons; gas neutralization; self-pinched transport; HIF and LIF transport, and relevance to common ion driver; LIF and HIF reactor concepts and relevance to common ion driver; atomic physics for common ion driver; code capabilities and needed improvement.

There are major differences between the safety principles for nuclear weapons and for nuclear reactors. For example, a principal concern for nuclear weapons is to prevent electrical energy from reaching the nuclear package during accidents produced by crashes, fires, and other hazards, whereas the foremost concern for nuclear reactors is to maintain coolant around the core in the event of certain system failures. Not surprisingly, new methods have had to be developed to assess the risk from nuclear weapons. These include fault tree transformations that accommodate time dependencies, thermal and structural analysis techniques that are fast and unconditionally stable, and Monte-Carlo-based sampling methods that incorporate intelligent searching. This paper provides an overview of the new methods for nuclear weapons, compares them with existing methods for nuclear reactors, identifies some of their dual-use characteristics, and discusses ongoing developmental activities.

The authors study the following problem: given a collection A of polyhedral parts in 3D, determine whether there exists a subset S of the parts that can be moved as a rigid body by an infinitesimal translation and rotation, without colliding with the rest of the parts, A/S. A negative result implies that the object whose constituent parts are the collection A cannot be taken apart with two hands. A positive result, together with the list of movable parts in S and a direction of motion for S, can be used by an assembly sequence planner. This problem has attracted considerable attention within and outside the robotics community. They devise an efficient algorithm to solve this problem. The solution is based on the ability to focus on selected portions of the tangent space of rigid motions and efficiently access these portions. The algorithm is complete (in the sense that it is guaranteed to find a solution if one exists), simple, and improves significantly over the best previously known solutions. The authors report experimental results with an implementation of their algorithm.

The first remediation of an Environmental Restoration (ER) Project site at Sandia National Laboratories (SNL) was successfully conducted in May and June 1994 at Technical Area II. The removal action involved four Uranium Calibration Pits (UCPs) filled with radioactive or hazardous materials. The concrete culvert pits were used to test and calibrate borehole radiometric logging tools for uranium exploration. The removal action consisted of excavating and containerizing the pit contents and contaminated soil beneath the culverts, removing the four culverts, and backfilling the excavation. Each UCP removal had unique complexities. Sixty 208-L drums of solid radioactive waste and eight 208-L drums of liquid hazardous waste were generated during the VCM. Two of the concrete culverts will be disposed as radioactive waste and two as solid waste. Uranium-238 was detected in UCP-2 ore material at 746 pci/g, and at 59 pci/g in UCP-1 silica sand. UCP-4 was empty; sludge from UCP-3 contained 122 mg/L (ppm) chromium.

An experiment involving migration of fluid and tracers (Li, Br, Ni) through a 6-m-high x 3-m-dia caisson Wedron 510 sand, is being carried out for Yucca Mountain Site Characterization Project. Sand`s surface chemistry of the sand was studied and a preliminary surface-complexation model of Ni adsorption formulated for transport calculations. XPS and leaching suggest that surface of the quartz sand is partially covered by thin layers of Fe-oxyhydroxide and Ca-Mg carbonate and by flakes of kaolinite. Ni adsorption by the sand is strongly pH-dependent, showing no adsorption at pH 5 and near-total adsorption at pH 7. Location of adsorption edge is independent of ionic strength and dissolved Ni concentration; it is shifted to slightly lower pH with higher pCO2 and to slightly higher pH by competition with Li. Diminished adsorption at alkiline pH with higher pCO2 implies formation of dissolved Ni-carbonato complexes. Ni adsorption edges for goethite and quartz, two components of the sand were also measured. Ni adsorption on pure quartz is only moderately pH-dependent and differs in shape and location from that of the sand, whereas Ni adsorption by goethite is strongly pH-dependent. A triple-layer surface-complexation model developed for goethite provides a good fit to the Ni-adsorption curve of the sand. Based on this model, the apparent surface area of the Fe-oxyhydroxide coating is estimated to be 560 m{sup 2}/g, compatible with its occurrence as amorphous Fe-oxyhydroxide. Potentiometric titrations on sand also differ from pure quartz and suggest that effective surface area of sand may be much greater than that measured by N{sub 2}-BET gas adsorption. Attempts to model the adsorption of bulk sand in terms of properties of pure end member components suggest that much of the sand surface is inert. Although the exact Ni adsorption mechanisms remain ambiguous, this preliminary adsorption model provides an initial set of parameters that can be used in transport calculations.

We have used several sol-gel strategies to prepare supported inorganic membranes by a process that combines the features of slip-casting and dip-coating. To be viable the deposited membranes must exhibit both high flux and high selectivity. For porous membranes these requirements are met by extremely thin, defect-free porous films exhibiting a narrow size distribution of very small pores. This paper considers the use of polymeric silica and hybrid-organosilyl precursor sols in the context of the underlying physics and chemistry of the membrane deposition process. Since the average membrane pore size is ultimately established by the collapse of the gel network upon drying, it is necessary to promote polymer interpenetration and collapse during membrane deposition in order to achieve the very small pore sizes necessary for molecular sieving. For polymeric sols, this is accomplished using rather weakly branched polymers characterized by fractal dimension D < 1.5 under deposition conditions in which the silica condensation rate is minimized. By analogy to organic polymer sols and gels, we believe that the breadth of the pore size distribution can be influenced by the occurrence of micro-phase separation during membrane deposition. Minimization of the condensation rate not only fosters polymer collapse but should inhibit phase separation, leading to a narrower pore size distribution. The formation of microporosity through collapse of the gel network requires that small pores are achieved at the expense of membrane porosity. Incorporation of organic template ligands within a dense silica matrix followed by their removal allows us to independently control pore size and pore volume through the size and volume fraction of the organic template. Such strategies can be used to create microporous films with large volume fraction porosities.

The Solar Thermal Design Assistance Center (STDAC) at Sandia is a resource provided by the DOE Solar Thermal Program. The STDAC`s major objective is to accelerate the use of solar thermal systems by providing direct technical assistance to users in industry, government, and foreign countries; cooperating with industry to test, evaluate, and develop renewable energy systems and components; and educating public and private professionals, administrators, and decision makers. This FY94 report highlights the activities and accomplishments of the STDAC. In 1994, the STDAC continued to provide significant direct technical assistance to domestic and international organizations in industry, government, and education, Applying solar thermal technology to solve energy problems is a vital element of direct technical assistance. The STDAC provides information on the status of new, existing, and developing solar technologies; helps users screen applications; predicts the performance of components and systems; and incorporates the experience of Sandia`s solar energy personnel and facilities to provide expert guidance. The STDAC directly enhances the US solar industry`s ability to successfully bring improved systems to the marketplace. By collaborating with Sandia`s Photovoltaic Design Assistance Center and the National Renewable Energy Laboratory the STDAC is able to offer each customer complete service in applying solar thermal technology. At the National Solar Thermal Test Facility the STDAC tests and evaluates new and innovative solar thermal technologies. Evaluations are conducted in dose cooperation with manufacturers, and the results are used to improve the product and/or quantify its performance characteristics. Manufacturers, in turn, benefit from the improved design, economic performance, and operation of their solar thermal technology. The STDAC provides cost sharing and in-kind service to manufacturers in the development and improvement of solar technology.

Recent results in the use of disilanes as silylating reagents for near-surface imaging with deep-UV (248 nm) and EUV (13.5 nm) lithography are reported. A relatively thin imaging layer of a photo-cross-linking resist is spun over a thicker layer of hard-baked resist that functions as a planarizing layer and antireflective coating. Photoinduced acid generation and subsequent heating crosslinks and renders exposed areas impermeable to an aminodisilane that reacts with the unexposed regions. Subsequent silylation and reactive ion etching afford a positive-tone image. The use of disilanes introduces a higher concentration of silicon into the polymer than is possible with silicon reagents that incorporate only one silicon atom per reactive site. The higher silicon content in the silylated polymer increases etching selectivity between exposed and unexposed regions and thereby increases the contrast. Additional improvements that help to minimize flow during silylation are also discussed, including the addition of bifunctional disilanes. We have resolved high aspect ratio, very high quality 0.20 {mu}m line and space patterns at 248 nm with a stepper having a numerical aperture (NA)= 0.53, and have resolved {<=} 0.15 {mu}m line and spaces at 13.5 nm.

Sputtered MoS{sub 2} is a solid lubricant capable of ultralow friction coefficients (below 0.05) load-bearing capacity. Since it exhibits low friction in vacuum, low outgassing rate, is non-migrating and lacks organic binders, this material is an attractive lubricant for space mechanisms. To exploit these new materials to their fullest potential, designers of space-based motion systems require data on the effects of atomic oxygen exposure on dense, sputtered MoS{sub 2}. This paper describes the effects of atomic oxygen in low earth orbit on the friction and surface composition of sputtered MoS{sub 2} films. Sputtered multilayer films of MoS{sub 2} with nickel (0.7 nm Ni per 10 nm MoS{sub 2}, for 1 {mu}m total film thickness), and MoS{sub 2} cosputtered with antimony oxide (nominally 2 {mu}m thick) were exposed to 2.2 to 2.5 x 10{sup 20} oxygen/cm{sup 2} over a period of 42.25 hours in earth orbit on the United States space shuttle. Identical specimens were kept as controls in desiccated storage for the duration of the mission, and another set was exposed to an equivalent fluence of atomic oxygen in the laboratory. The friction coefficient in air and vacuum, and the composition of worn surfaces, were determined prior to the shuttle flight and again after the shuttle flight. Results are described.

Thermal response and thermal fatigue tests of four 5 mm thick beryllium tiles on a Russian divertor mock-up were completed on the Electron Beam Test System at Sandia National Laboratories. The beryllium tiles were diffusion bonded onto an OFHC copper saddleblock and a DSCu (MAGT) tube containing a porous coating. Thermal response tests were performed on the tiles to an absorbed heat flux of 5 MW/m{sup 2} and surface temperatures near 300{degrees}C using 1.4 MPa water at 5.0 m/s flow velocity and an inlet temperature of 8-15{degrees}C. One tile was exposed to incrementally increasing heat fluxes up to 9.5 MW/m{sup 2} and surface temperatures up to 690{degrees}C before debonding at 10 MW/m{sup 2}. A third tile debonded after 9200 thermal fatigue cycles at 5 MW/m{sup 2}, while another debonded after 6800 cycles. In all cases, fatigue failure occurred in the intermetallic layers between the beryllium and copper. No fatigue cracking of the bulk beryllium was observed. During thermal cycling, a gradual loss of porous coating produced increasing sample temperatures. These experiments indicate that diffusion-bonded beryllium tiles can survive several thousand thermal cycles under ITER relevant conditions without failure. However, the reliability of the diffusion bonded Joint remains a serious issue.

This paper illustrates how different modes of operation such as bilateral teleoperation, autonomous control, and shared control can be described and implemented using combinations of modules in the SMART robot control architecture. Telerobotics modes are characterized by different ``grids`` of SMART icons, where each icon represents a portion of run-time code that implements a passive control law. By placing strict requirements on the module`s input-output behavior and using scattering theory to develop a passive sampling technique, a flexible, expandable telerobot architecture is achieved. An automatic code generation tool for generating SMART systems is also described.

This report provides brief summaries of research performed in chemical and physical sciences at Sandia National Laboratories. Programs are described in the areas of advanced materials and technology, applied physics and chemistry, lasers, optics, and vision, and resources and capabilities.

Industrial and military activities in the US produce large amounts of hazardous mixed waste, which includes both radioactive and toxic substances. The already overburdened environment is faced with the task of safely disposing of these complex wastes. A very important aspect of this effort is the safe and economical transportation of radioactive and toxic chemical wastes to projected repositories. Movement of wastes to the repository sites is accomplished by a combination of truck, rail, ship, and air. The DOE directs transportation activities including cask development technology for use in single or multimode transport. Sandia National Laboratories` Transportation Technology programs provide the technology and know-how to support DOE in achieving safe, efficient, and economical packaging and transportation of nuclear and other hazardous waste materials. This brochure describes the Transportation Technology programs and the specialized techniques and capabilities they offer to prospective users.

This report consists of one engineering drawing showing the design of the Fifth Wheel System for a semi-tractor trailer truck. Notes on the drawing give instructions for installation of some items, references to other drawings and instructions, and testing procedures.

This report consists of two engineering drawings showing the electrical and pneumatic system for the Fifth Wheel System on a semi-tractor trailer truck. The system is shown in the nonactivated state.

This report consists of one engineering drawing showing modifications to the Fifth Wheel System for a semi-tractor trailer truck. Notes give instructions for installation of some items, where other items may be purchased, testing instructions, and shipping instructions.

This report consists on one engineering drawing showing the wiring scheme for the Fifth Wheel System for a semi-tracker trailer truck. A note explains what wire is specified.

The Photovoltaic Manufacturing Technology (PVMaT) Project was initiated in 1990 to help the US photovoltaic (PV) industry extend its world leadership role in manufacturing and commercially developing PV modules and systems. It is being conducted in several phases, staggered to support industry progress. The four most recently awarded subcontracts (Phase 2B) are now completing their first year of research. They include two subcontracts on CdTe, one on Spheral Solar[trademark] Cells, and one on cast polysilicon. These subcontracts represent new technology additions to the PVMaT Project. Subcontracts initiated in earlier phases are nearing completion, and their progress is summarized. An additional phase of PVMaT, Phase 4A, is being initiated which will emphasize product-driven manufacturing research and development. The intention of Phase 4A is to emphasize improvement and cost reduction in the manufacture of full-system PV products. The work areas may include, but are not limited to, issues such as improvement of module manufacturing processes; system and system component packaging, integration, manufacturing, and assembly; product manufacturing flexibility; and balance-of-system development with the goal of product manufacturing improvements.

In coating processes (e.g. in blade coating) the flow domain inherently contains free surfaces and three-phase contact lines, and characteristic length scales of flow features in the dimension transverse to the web-movement vary by an order of magnitude or more from a fraction of a millimeter or more to tens of microns or less). The presence of free surfaces and three-phase contact lines, and the sudden changes of flow geometry and directions create difficulties in theoretical analyses of such flows. Though simulations of coating flows via finite-element methods using structured grids have been reportedly demonstrated in the literature, achieving high efficiency of such numerical experiments remains a grand challenge -- mainly due to difficulties in local mesh-refinement and in avoiding unacceptably distorted grids. High efficiency of computing steady flow fields under various process conditions is crucial in shortening turn-around time in design and optimization of coating-flow processes. In this paper we employ a fully-implicit, pseudo-solid, domain mapping technique coupled with unstructured meshes to analyze blade and slot coating flows using Galerkin`s method with finite element basis functions. We demonstrate the robustness and efficiency of our unique technique in circumventing shortcomings of mesh-motion schemes currently being used in the coating-flow research community. Our goal is to develop an efficient numerical tool, together with a suitable optimization toolkit, that can be used routinely in design and optimization of coating-flow processes.

This is a brief report about the Solar One and Solar Two instrument-energy-producing projects and the commercialization strategy for the Power Towers

The contact between an obsidian flow and a steep-walled tuff canyon was examined as an analogue for a highlevel waste repository. The analogue site is located in the Valles Caldera in New Mexico, where a massive obsidian flow filled a paleocanyon in the Battleship Rock tuff. The obsidian flow provided a heat source, analogous to waste panels or an igneous intrusion in a repository, and caused evaporation and migration of water. The tuff and obsidian samples were analyzed for major and trace elements and mineralogy by INAA, XRF, X-ray diffraction; and scanning electron microscopy and electron microprobe. Samples were also analyzed for D/H and {sup 39}Ar/{sup 4O} isotopic composition. Overall,the effects of the heating event seem to have been slight and limited to the tuff nearest the contact. There is some evidence of devitrification and migration of volatiles in the tuff within 10 meters of the contact, but variations in major and trace element chemistry are small and difficult to distinguish from the natural (pre-heating) variability of the rocks.

MELCOR is a fully integrated, engineering-level computer code, being developed at Sandia National Laboratories for the USNRC, that models the entire spectrum of severe accident phenomena in a unified framework for both BWRs and PWRS. As part, of an ongoing assessment program, the MELCOR computer code has been used to analyze a series of containment spray tests performed in the Containment Systems Experiment (CSE) vessel to evaluate the performance of aqueous sprays as a means of decontaminating containment atmospheres. Basecase MELCOR results are compared with test data, and a number of sensitivity studies on input modelling parameters and options in both the spray package and the associated aerosol washout and atmosphere decontamination by sprays modelled in the radionuclide package have been done. Time-step and machine-dependency calculations were done to identify whether any numeric effects exist in these CSE assessment analyses. A significant time-step dependency due to an error in the spray package coding was identified and eliminated. A number of other code deficiencies and inconveniences also are noted.

The responses of the following carbonate materials to shock loading and release have been measured: Indiana limestone (18% porosity; saturated and dry), Jeffersonville/Louisville Limestones (Fort Knox limestone) (variable dolomitization, low porosity), Danby Marble (essentially pure calcite; low porosity), and a limestone from the Utah Test and Training Range (low porosity, with 22% silica). Various experimental configurations were used, some optimized to yield detailed waveform information, others to yield a clean combination of Hugoniot states and release paths. All made use of velocity interferometry as a primary diagnostic. The stress range of 0 - 20 GPa was probed (in most cases, emphasizing the stress range 0 -10 GPa). The primary physical processes observed in this stress regime were material strength, porosity, and polymorphic phase transitions between the CaCO{sub 3} phases I, II, III and VI. Hydration was also a significant reaction under certain conditions. The Indiana Limestone studies in particular represent a significant addition to the low-pressure database for porous limestone. Temperature dependence and the effect of freezing were assessed for the Fort Knox limestone. Experimental parameters and detailed results are provided for the 42 impact tests in this series.

The Defense Nuclear Agency (DNA) is developing explosives technology through its Underground Technology Program (UTP). Sandia National Laboratories (SNL) has supported the DNA by conducting research to characterize the in situ stress and rock mass deformability at one of the UTP underground sites at Rodgers Hollow, near Louisville, Kentucky on the Fort Knox Military Reservation. The purpose of SNL`s testing was to determine the in situ stress using three different measurement techniques and, if possible, to estimate the rock mass modulus near the underground opening. The three stress-measuring techniques are (1) borehole deformation measurements using overcoring, (2) Anelastic Strain Recovery (ASR) complemented by laboratory ultrasonic and mechanical properties testing, and (3) the in situ flatjack technique using cancellation pressure. Rock mass modulus around the underground opening was estimated using the load deformation history of the flatjack and surrounding rock. Borehole deformation measurements using the overcoring technique probably represent the most reliable method for in situ stress determination in boreholes up to 50 ft (15 m) deep in competent rock around an isolated excavation. The technique is used extensively by the tunneling and mining industries. The ASR technique is also a core-based technique and is used in the petroleum and natural gas industries for characterization of in situ stress from deep boreholes. The flatjack technique has also been used in the tunneling and mining industries, and until recently has been limited to measurement of the stress immediately around the excavation. Results from the flatjack technique must be further analyzed to calculate the in situ stress in the far field.

The Department of Energy Order 5500.3A requires facility-specific hazards assessments be prepared, maintained, and used for emergency planning purposes. This consequence analysis documents the impact that a hydrogen accident could have to employees, the general public, and nearby facilities. The computer model ARCHIE was utilized to determine discharge rates, toxic vapor dispersion analyses, flammable vapor cloud hazards, explosion hazards, and flame jets for the Hydrogen Trailer Storage Facility located at Building 878. To determine over pressurization effects, hand calculations derived from the Department of the Air Force Manual, ``Structures to Resist the Effects of Accidental Explosions,`` were utilized. The greatest distances at which a postulated facility event will produce the Lower Flammability and the Lower Detonation Levels are 1,721 feet and 882 feet, respectively. The greatest distance at which 10.0 psi overpressure (i.e., total building destruction) is reached is 153 feet.

The Department of Energy Order 5500.3A requires facility-specific hazards assessments be prepared, maintained, and used for emergency planning purposes. This hazards assessment document describes the chemical and radiological hazards associated with the Sandia Administrative Micrographics Facility, Building 802. The entire inventory was screened according to the potential airborne impact to onsite and offsite individuals. The air dispersion model, ALOHA, estimated pollutant concentrations downwind from the source of a release, taking into consideration the toxicological and physical characteristics of the release site, the atmospheric conditions, and the circumstances of the release. The greatest distance at which a postulated facility event will produce consequences exceeding the Early Severe Health Effects threshold is 33 meters. The highest emergency classification is a Site Area Emergency. The Emergency Planning Zone is 75 meters.

A SEGS LS-2 parabolic trough solar collector was tested to determine the collector efficiency and thermal losses with two types of receiver selective coatings, combined with three different receiver configurations: glass envelope with either vacuum or air in the receiver annulus, and glass envelope removed from the receiver. As expected, collector performance was significantly affected by each variation in receiver configuration. Performance decreased when the cermet selective coating was changed to a black chrome coating, and progressively degraded as air was introduced into the vacuum annulus, and again when the glass envelope was removed from the receiver. For each receiver configuration, performance equations were derived relating collector efficiency and thermal losses to the operating temperature. For the bare receiver (no glass envelope) efficiency and thermal losses are shown as a function of wind speed. An incident angle modifier equation was also developed for each receiver case. Finally, equations were derived showing collector performance as a function of input insolation value, incident angle, and operating temperature. Results from the experiments were compared with predictions from a one-dimensional analytical model of the solar receiver. Differences between the model and experiment were generally within the band of experimental uncertainty.

Epitaxial SrRuO{sub 3} thin films were deposited by RF sputtering on SrTiO{sub 3} or MgO substrates for use as underlying electrodes. On these conductive substrates, epitaxial Pb(Zr{sub 0.35}Ti{sub 0.65})O{sub 3} (PZT) and PbTiO{sub 3} (PT) thin films were, deposited by metalorganic chemical vapor deposition (MOCVD). X-ray diffraction (XRD), RBS channeling (RBS), transmission electron microscopy (TEM) and optical waveguiding were used to characterize phase, microstructure, defect structure, refractive index, and film thickness of the deposited films. The PZT and PT films were epitaxial and c-axis oriented. 90{degree} domains, interfacial misfit dislocations and dislocations and threading dislocations were the primary structural defects, and the films showed a 70% RBS channeling reduction. Hysteresis and dielectric measurements of epitaxial PZT ferroelectric capacitor structures formed using evaporated Ag or ITO glass top electrode showed: a remanent polarization of 46.2 mC/cm{sup 2}, a coercive field of 54.9 KV/cm, a dielectric constant of 410, a bipolar resistivity of {approximately}5.8 {times} 10{sup 9} {Omega}-cm at a field of 275 KV/cm, and a breakdown strength of >400 KV/cm.

Coupled thermal and hydrologic flow processes have been recognized as important factors in the evaluation of Yucca Mountain as a potential repository for high-level radioactive wastes. As a result, several models and numerical codes such as TOUGH2 have been used to investigate the thermohydrologic conditions near a potential nuclear waste repository. However, very few of these models have been tested through laboratory or field scale studies. This work has therefore focused on modeling well-controlled experiments of non-isothermal flow processes in porous media at different scales to serve two primary objectives: (1) identify processes that are potentially important to thermal and hydrologic transport at Yucca Mountain and (2) build confidence in models and codes through combined experimental and numerical studies of thermohydrologic behavior at different scales and conditions. In this report, three independent studies of thermohydrologic flow processes at laboratory and field scales are presented. The experiments and field studies that are presented here were performed independently of this work. The main focus of this report was to use the numerical code TOUGH2 to simulate the non-isothermal flow behavior observed in each experiment to generate understanding of the thermohydrologic processes and to gain confidence in the code. TOUGH2 was chosen due to its current use in calculations associated with Yucca Mountain and its capability of modeling the coupled transport of air, water, vapor, and heat in porous media.

High heat flux testing for the United States fusion power program is the primary mission of the Plasma Materials Test Facility (PMTF) located at Sandia National Laboratories - New Mexico. This facility, which is owned by the United States Department of Energy, has been in operation for over 17 years and has provided much of the high heat flux data used in the design and evaluation of plasma facing components for many of the world's magnetic fusion, tokamak experiments. In addition to domestic tokamaks such as Tokamak Fusion Test Reactor (TFTR) at Princeton and the DIII-D tokamak at General Atomics, components for international experiments like TEXTOR, Tore-Supra, and JET also have been tested at the PMTF. High heat flux testing spans a wide spectrum including thermal shock tests on passively cooled materials, thermal response and thermal fatigue tests on actively cooled components, critical heat flux-burnout tests, braze reliability tests and safety related tests. The objective of this article is to provide a brief overview of the high heat flux testing capabilities at the PMTF and describe a few of the experiments performed over the last year.

Radionuclide releases due to drilling into the potential Yucca Mountain nuclear-waste repository have been evaluated as part of a recent total-system performance assessment. The probability that a drilling event intersects a waste package is a function of the sizes of the drill bit and the waste package, and the density of placement of the containers in the repository. The magnitude of the releases is modeled as a random function that also depends on the amount of decay the radionuclides have undergone. Four cases have been analyzed, representing the combinations of two waste-package designs (small-capacity, thin-wall, vertically emplaced; and large-capacity, thick-wall, horizontally emplaced) and two repository layouts (lower thermal power dissipation, low waste-package placement density; and higher thermal power dissipation, high waste-package placement density). The results show a fairly pronounced dependence on waste-package design and slight dependence on repository layout. Given the assumptions in the model, releases from the larger containers are 4-5 times greater than from the smaller packages.

Polycarbonate rectangular honeycomb and acrylic capillary honeycomb, two types of transparent insulation material, were tested in flat-plate collectors. The honeycomb was inserted between the cover plate and the absorber, leaving a 1-cm air gap above the absorber to decouple radiative and conductive heat-transfer modes. Four 4 by 8 ft. collectors with selective black chrome absorbers were evaluated side by side using ASHRAE Standard 93-1986. They differed in thickness and type of material as follows: 1) no insulation material, 2) 1 in. of polycarbonate, 3) 4-in. of polycarbonate, and 4) 4 in. of acrylic honeycomb. Another set of tests was completed using absorbers coated with moderately selective black paint, and a third set with flat-black paint. A collector containing a selective chrome absorber and 4 in. of acrylic honeycomb achieved the best thermal performance. The amount of improvement in thermal performance was greatest when transparent insulation material was added to collectors with flat-black absorbers, and it decreased as absorber selectivity increased. Since small-cell honeycomb improves thermal performance by suppressing both convective and radiative transfer, combination with selective coatings is partially redundant because they are poor emitters. Also, the unacceptably low melting temperature of these materials preclude them from withstanding even a wet stagnation, thereby rendering this application impractical.

When a modal test is to be performed for purposes of correlation with a finite element model, one needs to design the test so that the resulting measurements will provide the data needed for the correlation. There are numerous issues to consider in the design of a modal test; two important ones are the number and location of response sensors, and the number, location, and orientation of input excitation. From a model correlation perspective, one would like to select the response locations to allow a definitive, one-to-one correspondence between the measured modes and the predicted modes. Further, the excitation must be designed to excite all the modes of interest at a sufficiently high level so that the modal estimation algorithms can accurately extract the modal parameters. In this paper these two issues are examined in the context of model correlation with methodologies presented for obtaining an experiment design.

A sensor-based control approach for real-time seam tracking of rocket thrust chamber assemblies has been developed to enable automation of a braze paste dispensing process. This approach utilizes a non-contact Multi-Axis Seam Tracking (MAST) sensor to track the seams. The MAST sensor measures capacitance variations between the sensor and the workpiece and produces four varying voltages which are read directly into the robot controller. A PID control algorithm which runs at the application program level has been designed based upon a simple dynamic model of the combined robot and sensor plant. The control algorithm acts on the incoming sensor signals in real-time to guide the robot motion along the seam path. Experiments demonstrate that seams can be tracked at 100 mm/sec within the accuracy required for braze paste dispensing.

Prosperity Games are an outgrowth and adaptation of move/countermove and seminar War Games. Prosperity Games are simulations that explore complex issues in a variety of areas including economics, politics, sociology, environment, education and research. These issues can be examined from a variety of perspectives ranging from a global, macroeconomic and geopolitical viewpoint down to the details of customer/supplier/market interactions in specific industries. All Prosperity Games are unique in that both the game format and the player contributions vary from game to game. This report documents a 90-minute Prosperity Game conducted as part of Advanced Manufacturing Day on May 17, 1994. This was the fourth game conducted under the direction of the Center for National Industrial Alliances at Sandia. Although previous games lasted from one to two days, this abbreviated game produced interesting and important results. Most of the strategies proposed in previous games were reiterated here. These included policy changes in international trade, tax laws, the legal system, and the educational system. Government support of new technologies was encouraged as well as government-industry partnerships. The importance of language in international trade was an original contribution of this game. The deliberations and recommendations of these teams provide valuable insights as to the views of this diverse group of decision makers concerning policy changes, foreign competition, and the development, delivery and commercialization of new technologies.

A significant number of analytical problems (for example, abnormal-environment safety analysis) depend on data that are partly or mostly subjective. Since fuzzy algebra depends on subjective operands, we have been investigating its applicability to these forms of assessment, particularly for portraying uncertainty in the results of PRA (probabilistic risk analysis) and in risk-analysis-aided decision-making. Since analysis results can be a major contributor to a safety-measure decision process, risk management depends on relating uncertainty to only known (not assumed) information. The uncertainties due to abnormal environments are even more challenging than those in normal-environment safety assessments; and therefore require an even more judicious approach. Fuzzy algebra matches these requirements well. One of the most useful aspects of this work is that we have shown the potential for significant differences (especially in perceived margin relative to a decision threshold) between fuzzy assessment and probabilistic assessment based on subtle factors inherent in the choice of probability distribution models. We have also shown the relation of fuzzy algebra assessment to ``bounds`` analysis, as well as a description of how analyses can migrate from bounds analysis to fuzzy-algebra analysis, and to probabilistic analysis as information about the process to be analyzed is obtained. Instructive examples are used to illustrate the points.

Many organizations face high consequence safety situations where unwanted stimuli due to accidents, catastrophes, or inadvertent human actions can cause disasters. In order to improve interaction among such organizations and to build on each others` experience, preventive approaches, and assessment techniques, the High Consequence Operations Safety Symposium was held July 12--14, 1994 at Sandia National Laboratories, Albuquerque, New Mexico. The symposium was conceived by Dick Schwoebel, Director of the SNL Surety Assessment Center. Stan Spray, Manager of the SNL System Studies Department, planned strategy and made many of the decisions necessary to bring the concept to fruition on a short time scale. Angela Campos and about 60 people worked on the nearly limitless implementation and administrative details. The initial symposium (future symposia are planned) was structured around 21 plenary presentations in five methodology-oriented sessions, along with a welcome address, a keynote address, and a banquet address. Poster papers addressing the individual session themes were available before and after the plenary sessions and during breaks.

This report is a critical reassessment of the geotechnical risks of continuing oil storage at the Weeks Island Strategic Petroleum Reserve site. It reviews all previous risk abatement recommendations, subsequent mitigative actions, and new information. Of increased concern, due to the discovery of a surface levels, is the long term maintainability of the mine as an oil storage repository. Mine operational changes are supported in order to facilitate monitoring of water entry diagnostics. These changes are also intended to minimize the volume in the mine available for water entry. Specific recommendations are made to implement the mine changes.

The design of structural containments for testing small explosive devices requires the designer to consider the various aspects of the explosive loading, i.e., shock and gas or quasistatic pressure. Additionally, if the explosive charge has the potential of producing damaging fragments, provisions must be made to arrest the fragments. This may require that the explosive be packed in a fragment attenuating material, which also will affect the loads predicted for containment response. Material also may be added just to attenuate shock, in the absence of fragments. Three charge weights are used in the design. The actual charge is used to determine a design fragment. Blast loads are determined for a {open_quotes}design charge{close_quotes}, defined as 125% of the operational charge in the explosive device. No yielding is permitted at the design charge weight. Blast loads are also determined for an over-charge, defined as 200% of the operational charge in the explosive device. Yielding, but no failure, is permitted at this over-charge. This guide emphasizes the calculation of loads and fragments for which the containment must be designed. The designer has the option of using simplified or complex design-analysis methods. Examples in the guide use readily available single degree-of-freedom (sdof) methods, plus static methods for equivalent dynamic loads. These are the common methods for blast resistant design. Some discussion of more complex methods is included. Generally, the designer who chooses more complex methods must be fully knowledgeable in their use and limitations. Finally, newly fabricated containments initially must be proof tested to 125% of the operational load and then inspected at regular intervals. This specification provides guidance for design, proof testing, and inspection of small explosive containment structures.

Feature extraction transforms an object's image representation to an alternate reduced representation. In one-class object recognition, we would like this alternate representation to give improved discrimination between the object and all possible non-objects and improved generalization between different object poses. Feature selection can be time-consuming and difficult to optimize so we have investigated unsupervised neural networks for feature discovery. We first discuss an inherent limitation in competitive type neural networks for discovering features in gray level images. We then show how Sanger's Generalized Hebbian Algorithm (GHA) removes this limitation and describe a novel GHA application for learning object features that discriminate the object from clutter. Using a specific example, we show how these features are better at distinguishing the target object from other non-target objects with Carpenter's ART 2-A as the pattern classifier.

This report summarizes the results for the first year of a two year Laboratory Directed Research and Development (LDRD) effort. This effort included a system study, preliminary data acquisition, and preliminary algorithm development. The system study determined the optimum frequency and bandwidth, surveyed soil parameters and targets, and defined radar cross section in lossy media. The data acquisition imaged buried objects with a rail-SAR. Algorithm development included a radar echo model, three-dimensional processing, sidelobe optimization, phase history data interpolation, and clutter estimation/cancellation.

Robotic automation is examined as a possible alternative to manual spent nuclear fuel, transport cask and Multi-Purpose Canister (MPC) handling at a Monitored Retrievable Storage (MRS) facility. Automation of key operational aspects for the MRS/MPC system are analyzed to determine equipment requirements, throughput times and equipment costs is described. The economic and radiation dose impacts resulting from this automation are compared to manual handling methods.

The potential radiological and nonradiological risks associated with specific radioactive waste shipping campaigns at the Hanford Site are estimated. The shipping campaigns analyzed are associated with the transportation of wastes from the N-Reactor site at the 200-W Area, both within the Hanford Reservation, for disposal. The analysis is based on waste that would be generated from the N-Reactor stabilization program.

Verification measurements may be used to help ensure nuclear criticality safety when burnup credit is applied to spent fuel transport and storage systems. The FORK measurement system, designed at Los Alamos National Laboratory for the International Atomic Energy Agency safeguards program, has been used to verify reactor site records for burnup and cooling time for many years. The FORK system measures the passive neutron and gamma-ray emission from spent fuel assemblies while in the storage pool. This report deals with the application of the FORK system to burnup credit operations based on measurements performed on spent fuel assemblies at the Oconee Nuclear Station of Duke Power Company.

A method is presented for input torque shaping for three-dimensional slew maneuvers of a precision pointing flexible spacecraft. The method determines the torque profiles for fixed-time, rest-to-rest maneuvers which minimize a specified performance index. Spacecraft dynamics are formulated in such a manner that the rigid body and flexible motions are decoupled. Furthermore, assembly of the equations of motion is simplified by making use of finite element analysis results. Input torque profiles are determined by solving an associated optimization problem using dynamic programming. Three example problems are provided to demonstrate the application of the method.

Lead zirconate titanate (PZT) thin films are of technological interest for a variety of electronic and optical applications. Fabrication of PZT films by solution deposition techniques is attractive because of stoichiometric control at the molecular level, ease of processing, and both low capital investment and total cost. Control of phase evolution, microstructure, crystallite size and orientation, and ferroelectric domain assemblage during processing is essential to optimize electrical and/or optical properties of the films. Electron microscopy techniques have been used extensively to correlate microstructural features with film processing.

This paper addresses theoretical aspects of forming images from an airborne Synthetic Aperture Radar (SAR) of targets buried below the earth's surface. Soil is generally a lossy, dispersive medium, with wide ranging variability in these attributes depending on soil type, moisture content, and a host of other physical properties. Focussing a SAR subsurface image presents new dimensions of complexity relative to its surface-image counterpart, even when the soil's properties are known. This paper treats the soil as a lossy, dispersive half space, and presents a practical model for the radar echo-delay time to point scatterers within it. This model is then used to illustrate effects of refraction, dispersion, and attenuation on a SAR's phase histories, and the resulting image. Various data collection geometries and processing strategies are examined for both 2-Dimensional and 3-Dimensional SAR images. The conclusions from this work are that 1) focussing a SAR image must generally take into account both refraction and dispersion, 2) resolving targets at different depths in lossy soils requires perhaps unprecedented sidelobe attenuation, that for some soils may only be achievable with specialized window functions, 3) the impulse response of the soil itself places a practical limit on the usable bandwidth of the radar, and 4) dynamic ranges and sensitivities will need to be orders of magnitude greater than typical surface-imaging SARs, leading to significant impact on SAR parameters, for example compressing the usable range of pulse repetition frequencies (PRFs).

This paper demonstrates how certain concepts from the Phase Gradient Autofocus (PGA) algorithm for automated refocus of spotlight mode SAR imagery may be used to design a similar algorithm that applies to SAR imagery formed in the conventional strip-mapping mode. The algorithm derivation begins with the traditional view of strip-map image formation as convolution (compression) using a linear FM chirp sequence. The appropriate analogies and modifications to the spotlight mode case are used to describe a working algorithm for strip-map autofocus.

Statistical methods were used to design and analyze the results of a gettering experiment on four industrial multicrystalline silicon solar cell materials. The experiment studied the effects of temperature and time in the POCl3 diffusion process and the aluminum alloy process using simple diagnostic devices. The time and temperature ranges were restricted to maintain compatibility with commercial fabrication sequences. The design was capable of picking up second order interactions between the various processing factors. Statistically significant gettering effects were detected in only two of the four materials. The results for one of these materials were further tested using full solar cells. Strengths and weaknesses of this approach to gettering studies have become apparent in the present work and are discussed.

Computational physicists at Sandia National Laboratories have moved their production codes to distributed memory parallel computers. Such an effort required the development of parallel algorithms, parallel data bases and parallel support tools. The Eulerian CTH code was rewritten. Moving both ALEGRA and PRONTO to parallel computers required only a modest number of modifications. It involved restructuring the restart and graphics data bases to make them parallel and minimize the I/O to the parallel computer. It also involved developing mesh decomposition tools to divide a rectangular or arbitrary connectivity into sub-meshes. It also involved developing new visualization tools to process the very large, parallel data bases. This paper also discusses Sandia's experiences running these codes on its 1840 compute node Intel Paragon, 1024 processor nCUBE and networked stations.

Techniques for lossless waveform compression can be applied to the transmission of weight vectors from an orbiting satellite. The vectors, which are a part of a hybrid analog/digital adaptive filter, are a representation of the radio frequency background seen by the satellite. An approach is used which treats each adaptive weight as a time-varying waveform.

Transformers models for simulation with Pspice and Analogy's Saber are being developed using experimental B-H Loop and network analyzer measurements. The models are evaluated for accuracy and convergence using several test circuits. Results are presented which demonstrate the effects on circuit performance from magnetic core losses, eddy currents, and mechanical stress on the magnetic cores.

This paper describes the result of a team effort at Sandia to demonstrate the near-term performance potential for multicrystalline silicon modules using commercial mc-Si material and improved cell fabrication processes. Large-area high-performance mc-Si cells were fabricated, prototype modules were built, and world-record module efficiency was confirmed by outdoor testing at over 15% for standard test conditions.

Abstract not provided.

Abstract not provided.

We have developed a capability to make real time concentration measurements of individual chemicals in a complex mixture using a multispectral laser remote sensing system. Our chemical recognition and analysis software consists of three parts: (1) a rigorous multivariate analysis package for quantitative concentration and uncertainty estimates, (2) a genetic optimizer which customizes and tailors the multivariate algorithm for a particular application, and (3) an intelligent neural net chemical filter which pre-selects from the chemical database to find the appropriate candidate chemicals for quantitative analyses by the multivariate algorithms, as well as providing a quick-look concentration estimate and consistency check. Detailed simulations using both laboratory fluorescence data and computer synthesized spectra indicate that our software can make accurate concentration estimates from complex multicomponent mixtures. even when the mixture is noisy and contaminated with unknowns.

This paper discusses the conceptual design considerations and challenges for development of a contactless, mobile, single channel biomagnetic sensor system based on High-Temperature Superconductor (HTS) Superconducting Quantum Interference Devices (SQUIDs) and employing the Three-SQUID Gradiometer (TSG) concept. Operating in magnetically unshielded environments, as are encountered in many medical scenarios, this instrument class would monitor cardiac electrical activity with minimal patient preparation and intrusiveness, and would notionally be coupled with a clinically adaptive human-system interface (HSI).

Hydroxylated alumina films have been synthesized by water oxidation of single crystal Al(110) surfaces. Thermal dehydroxylation results in anion vacancies which produce an Al(3s) defect state 3.5 eV below the conduction band edge. A maximum in the defect-DOS occurs for oxides heated to 350 to 400C, which is where the materials exhibit maximum Lewis acidity with respect to C{sub 2}H{sub 4}. Adsorbed C{sub 2}H{sub 4} produces thermally active C{sub 2} species which interact covalently with the defect-DOS and nonbonding O(2p) from the top of the valence band. C(1s) binding energies suggest significant charge transfer which is consistent with a carbenium ion. Ni evaporated onto the surface, however, transfers charge directly to Al species and does not interact with O atoms at the defect site. The defect-DOS is regenerated when the C{sub 2} species decomposes or when Ni migrates thermally through the oxide layer.

This is the first annual report since the Inauguration of the University Center of Excellence for Photovoltaics Research and Development (UCEP) at Georgia Tech. The essential objective of the Center is to improve the fundamental understanding of the science and technology of advanced PV devices and materials, to provide training and enrich the educational experience of students in the field, and to increase US competitiveness by providing guidelines to industry and DOE for achieving cost-effective and high efficiency PV devices. These objectives are to be accomplished through a combination of research and education. This report summarizes the technical accomplishments, including modeling, processing, and characterization of cast multicrystalline silicon solar cells; use of modeling and PCD measurements to develop a road map for progressing toward 20% multicrystalline and 25% single crystalline cells; the development of a novel PECVD SiN/SiO{sub 2} AR coating that also provides good surface passivation; PECVD deposited SiO{sub 2} films with record low S and D{sub it} at the SiO{sub 2}/Si interface; and educational activities and accomplishments.

The International Energy Agency Fossil Fuel Multiphase Flow Sciences Agreement has been in effect since 1986. The traditional mechanism for the effort has been information exchange, effected by the inclusion of scientists in annual Executive committee meetings, by exchange of reports and papers, and by visits of scientists to one another`s institutions. In a sequence of informal meetings and at the 1993 Executive committee meeting, held in Pittsburgh, US in March 1994, it was decided that more intensive interactions could be productive. A candidate for such interactions would be specific projects. Each of these would be initiated through a meeting of scientists in which feasibility of the particular project was decided, followed by relatively intense international co-operation in which the work would be done. This is a report of the first of these meetings. Official or unofficial representatives from Canada, italy, japan, mexico, the United Kingdom, and the US met in Albuquerque, New Mexico, US, to consider the subject Flows of Granular Materials in Complex Geometries. Representatives of several other countries expressed interest but were unable to attend this meeting. Sixteen lectures were given on aspects of this topic. It was decided that a co-operative effort was desirable and possible. The most likely candidate for the area of study would be flows in bins and hoppers. Each of the countries wishing to co-operate will pursue funding for its effort. This report contains extended abstracts of the sixteen presentations and a transcription of the final discussion.

Sandia National Laboratories operates the Primary Standards Laboratory for the Department of Energy, Albuquerque Operations Office (DOE/AL). This report summarizes metrology activities that received emphasis in the first half of 1994 and provides information pertinent to the operation of the DOE/AL system-wide Standards and Calibration Program.

The finite difference flow and transport simulator VS2DT was benchmark tested against several other codes which solve the same equations (Richards equation for flow and the Advection-Dispersion equation for transport). The benchmark problems investigated transient two-dimensional flow in a heterogeneous soil profile with a localized water source at the ground surface. The VS2DT code performed as well as or better than all other codes when considering mass balance characteristics and computational speed. It was also rated highly relative to the other codes with regard to ease-of-use. Following the benchmark study, the code was verified against two analytical solutions, one for two-dimensional flow and one for two-dimensional transport. These independent verifications show reasonable agreement with the analytical solutions, and complement the one-dimensional verification problems published in the code`s original documentation.

Data are presented from the intermediate scale borehole test, an in situ test fielded in the pillar separating Rooms C1 and C2 at the Waste Isolation Pilot Plant (WIPP). The test was to provide data on the influence of scale, if any, on the structural behavior of underground openings in salt. These data include selected fielding information, test configuration, instrumentation activities, and comprehensive results from a large number of gages. Construction of the test began in December 1989, with the drilling of the intermediate scale borehole in December 1990. Gage data in this report cover the period from January 1989 through June 1993.

An optical technique for high-power radio-frequency (RF) signal generation is described. The technique uses a unique photodetector based on a traveling-wave design driven by an appropriately modulated light source. The traveling-wave photodetector (TWPD) exhibits simultaneously a theoretical quantum efficiency approaching 100 % and a very large electrical bandwidth. Additionally, it is capable of dissipating the high-power levels required for the RF generation technique. The modulated light source is formed by either the beating together of two lasers or by the direct modulation of a light source. A system example is given which predicts RF power levels of 100`s of mW`s at millimeter wave frequencies with a theoretical ``wall-plug`` efficiency approaching 34%.

US industry produces about 12 billion tons of waste a year, or two-thirds of the waste generated in the US. The costs of handling and disposing of these wastes are significant, estimated to be between $25 and $43 billion in 1991, and represent an increase of 66% since 1986. US industry also uses about one-third of all energy consumed in the nation, which adds to the environmental burden. Industrial wastes affect the environmental well-being of the nation and, because of their growing costs, the competitive abilities of US industry. As part of a national effort to reduce industrial wastes, the US Congress passed the Energy Policy Act (EPAct, P.L. 102-486). Section 2108, subsections (b) and (c), of EPAct requires the Department of Energy (DOE) to identify opportunities to demonstrate energy efficient pollution prevention technologies and processes; to assess their availability and the energy, environmental, and cost effects of such technologies; and to report the results. Work for this report clearly pointed to two things, that there is insufficient data on wastes and that there is great breadth and diversity in the US industrial sector. This report identifies: information currently available on industrial sector waste streams, opportunities for demonstration of energy efficient pollution prevention technologies in two industries that produce significant amounts of waste--chemicals and petroleum, characteristics of waste reducing and energy saving technologies identifiable in the public literature, and potential barriers to adoption of waste reducing technologies by industry.

On October 24, 1992, the President signed the Energy Policy Act of 1992 (EPAct, Public Law 102-486). Section 2108, subsections (b) and (c), of EPAct requires the Department of Energy to identify opportunities to demonstrate energy efficient pollution prevention technologies and processes; to assess the availability and the energy, environmental, and cost effects of such technologies; and to report the results within one year. This report is in response to that requirement. National waste reduction efforts in both the private and public sectors encompass a variety of activities to decrease the amount of wastes that ultimately enter their air, water, and land. DOE`s Office of Industrial Technologies (DOE/OIT) recognized the importance of these efforts and confirmed the federal government`s commitment to waste reduction by establishing the Industrial Waste Program (IWP) in 1990. The program is driven by industry and national needs, and is working on new technologies and information dissemination that industry identifies as vital. The national benefits of new technologies do not accrue to the economy until transferred to industry and incorporated into commercially available processes or products.

FAROW is a Computer program that assists in the probabilistic analysis of the Fatigue and Reliability of wind turbines. The fatigue lifetime of wind turbine components is calculated using functional forms for important input quantities. Parameters of these functions are defined in an input file as either constants or random variables. The user can select from a library of random variable distribution functions. FAROW uses structural reliability techniques to calculate the mean time to failure, probability of failure before a target lifetime, relative importance of each of the random inputs, and the sensitivity of the reliability to all input parameters. Monte Carlo simulation is also available. This user`s manual is intended to provide sufficient information to knowledgeably run the program and meaningfully interpret the results. The first chapter provides an overview of the approach and the results. Chapter 2 describes the formulation and assumptions used in the fatigue life calculations. Each of the input parameters is described in detail in Chapter 3 along with hints and warnings on usage. An explanation of the outputs is provided in Chapter 4. Two example problems are described and solved in Chapter 5, one for the case where extensive data are available and the other with limited data where the uncertainty is higher. A typical input file and the output files for the example problems are included in the appendices.

Concern for the environment and cost reduction are driving forces for a broad effort in government and the private sector to develop new, more cost-effective technologies for characterizing, monitoring and remediating environmental sites. Secondary goals of the characterization, monitoring and remediation (CMR) activity are: minimize secondary waste generation, minimize site impact, protect water tables, and develop methods/strategies to apply new technologies. The Sandia National Laboratories (SNL) project in directional boring for CMR of waste sites with enhanced machinery from the underground utility installation industry was initiated in 1990. The project has tested a variety of prototype machinery and hardware built by the industrial partner, Charles Machine Works (CMW), and SNL at several sites (Savannah River Site (SRS), Hanford, SNL, Kirtland AFB (KAFB), CMW), successfully installed usable horizontal environmental test wells at SRS and SNL/KAFB, and functioned as a clearing house for information regarding application of existing commercial machinery to a variety of governmental and commercial sites. The project has continued to test and develop machinery in FY 94. The original goal of cost-effectiveness is being met through innovation, adaptation, and application of fundamental concepts. Secondary goals are being met via a basic philosophy of {open_quotes}cut/thrust and compact cuttings without adding large quantities of fluid{close_quotes} to an environmental problem site. This technology will be very cost-effective where applicable. Technology transfer and commercialization by CMW is ongoing and will continue into FY 95. Technology transfer to the private sector is ongoing and reflected in increasing machinery sales to environmental contractors. Education of regulatory agencies resulting in restructuring of appropriate regulatory standards for specification of the horizontal drilling techniques continues to be a long-range goal.

This 1993 report contains monitoring data from routine radiological and nonradiological environmental surveillance activities. Summaries of significant environmental compliance programs in progress, such as National Environmental Policy Act documentation, environmental permits, environmental restoration, and various waste management programs for Sandia National Laboratories in Albuquerque, New Mexico, are included. The maximum offsite dose impact was calculated to be 0.0016 millirem. The total population within a 50-mile (80 kilometer) radius of Sandia National Laboratories/New Mexico received an estimated collective dose of 0.027 person-rem during 1993 from the laboratories operations, As in the previous year, the 1993 operations at Sandia National Laboratories/New Mexico had no discernible impact on the general public or on the environment. This report is prepared for the U.S. Department of Energy in compliance with DOE Order 5400.1.

Results of recent studies of the electronic properties of polysilanes are reviewed. The electronic states can be described by the Hueckel model if coulomb interactions are included using the Pariser-Parr-Pople approximation. The long polymer chains appear to be divided into random length, short, ordered segments by conformational defects, with the energy of the excited states depending on the length of the segments. In isolated polymer chains energy is transferred from high-energy, short segments to longer, lower energy segments but the distance and time during which transfer take place is very limited. In solid films the excitons become highly mobile and remain mobile throughout their lifetime, even at low temperatures. Holes are quite mobile in solid films and the characteristics of transport are the same as those of charge carrier transport in molecularly doped polymer films.

A series of tests to evaluate several types of environmental well casings have been conducted by Sandia National Laboratories (SNL) and it`s industrial partner, The Charles Machine Works, Inc. (CMW). A test bed was constructed at the CMW test range to model a typical shallow, horizontal, directionally drilled wellbore. Four different types of casings were pulled through this test bed. The loads required to pull the casings through the test bed and the condition of the casing material were documented during the pulling operations. An additional test was conducted to make a comparison of test bed vs actual wellbore casing pull loads. A directionally drilled well was emplaced by CMW to closely match the test bed. An instrumented casing was installed in the well and the pull loads recorded. The completed tests are reviewed and the results reported.

The disposal of liquid organic solvents in unlined pits at the Sandia National Laboratories Chemical Waste Landfill (CWL) has created an organic solvent vapor plume in the subsurface soils. The groundwater, at a depth of 485 feet below ground surface, shows contamination by the vapor plume. The primary strategy to remove the volatile organic constituents from the soil include methods based on vacuum vapor extraction technologies. These technologies utilize the physical process of inducing air flow through the soils, into an extraction well, and to the surface for collection and/or treatment. The ability of the soils to be ventilated by a vacuum vapor extraction system is primarily dependent on the permeability of the soil. However, soil stratigraphic layers can have different permeabilities due to the differences in soil texture (percentages of sand, silt, and clay) and soil structure (bulk density and pore size distribution). These differences can create local soil horizons that are preferentially ventilated. The less ventilated zones will prolong the removal of vapor phase contaminants. This will increase the time needed to reach the remediation cleanup levels. Air permeability estimates at sequential depth horizons would provide valuable design input for segmented well screen completion zones that may improve removal efficiency of vacuum vapor extraction systems. Soil permeability characterization can be accomplished in many ways including laboratory tests, field scale tests, and reference to analogous soil texture properties. The work presented here represents an evaluation of soil permeability test methods at selected locations of the CWL.

The results of the numerical simulations reveal that horizontal air flow through the coarse with reasonable pressure gradients can remove large quantities of water from the cover system. Initially, the water removal from the cover system is dominated by the evaporation and advection of water vapor out of the coarse layer. Once the coarse layer is dry, removal of water by evaporation near the fine/coarse layer interface reduces the local water content and water potential, and water moves toward the fine-coarse layer interface and becomes available for evaporation. This result is important in that it suggests the fine layer water content may be moderated by air flow in the coarse layer. Incorporating diffusion of water vapor from the fine layer into the coarse layer substantially increases the water movement out of the fine layer.

Soil heating technologies have been proposed as a method to accelerate contaminant removal from subsurface soils. These methods include the use of hot air, steam, conductive heaters, in-situ resistive heating and in-situ radiofrequency heating (Buettner et.al., EPA, Dev et.al., Heath et.al.). Criteria for selection of a particular soil heating technology is a complex function of contaminant and soil properties, and efficiency in energy delivery and contaminant removal technologies. The work presented here seeks to expand the understanding of the interactions of subsurface water, contaminant, heat and vacuum extraction through model predictions and field data collection. Field demonstration will involve the combination of two soil heating technologies (resistive and dielectric) with a vacuum vapor extraction system and will occur during the summer of 1994.

Abstract not provided.

Physical Optical Corporation has introduced a Light Shaping Diffuser{trademark} (LSD) for the specialized illumination requirements of aircraft inspection. Attached to a handheld, battery-powered flashlight, this light-weight, holographic diffuser element provides bright, even illumination as aircraft inspectors perform the important task of visually examining aircraft for possible structural defects. Field trials conducted by the Aging Aircraft Program at Sandia National Laboratories confirm that the LSD-equipped flashlights are preferred by visual inspectors over stock flashlights.

A conceptual design for an air-launched interceptor missile to defend against theater ballistic missiles is presented. The missile is designed to intercept the target while ascending, during Or just after the boost phase, before it reaches exo-atmospheric flight. The interceptor consists of a two-stage booster and a shrouded kinetic-kill vehicle. This report concentrates on the booster design required to achieve reasonable standoff ranges. The kinetic-kill vehicle and shroud (the payload) is assumed to weigh 80 lb{sub m} (36 kg) and assumed to contain guidance computers for both the kill vehicle and the booster. The interceptor missile is about 6 m long, .48 m in diameter and weighs about 900 kg. Allowing 25 sec for target detection, trajectory estimation, and interceptor launch, it can intercept 90 sec after target launch from a 220 km stand-off range at an altitude of 60 km. Trade-off studies show that the interceptor performance is most sensitive to the stage mass fractions (with the first-stage mass fraction the most important), the first-stage burn time and the payload weight.

The torque loads on two classes of wind turbine gearboxes are analyzed using a time-at-torque technique and a rainflow counting technique to determine the cyclic loads on the gear teeth. The two techniques are compared and contrasted to one another using representative samples of the time histograms from a Micon 65 and the Sandia/DOE Test Bed wind turbines. To place these differences in perspective, Miner’s Rule is used to determine the damage produced by each of the distributions. The damage analyses illustrate that the differences in the distributions are minimal.

Sandia National Laboratories/New Mexico (SNL/NM) has established a formal facility assessment, decontamination and demolition oversight process with the goal of ensuring that excess or contaminated facilities are managed in a cost-effective manner that is protective of human health and the environment. The decontamination and demolition process is designed so that all disciplines are consulted and have input from the initiation of a project. The committee consists of all essential Environmental, Safety and Health (ES and H) and Facilities disciplines. The interdisciplinary-team approach has provided a mechanism that verifies adequate building and site assessment activities are conducted. This approach ensures that wastes generated during decontamination and demolition activities are handled and disposed according to Department of Energy (DOE), Federal, state, and local requirements. Because of the comprehensive nature of the SNL decontamination and demolition process, the strategy can be followed for demolition, renovation and new construction projects, regardless of funding source. An overview of the SNL/NM decontamination and demolition process is presented through a case study which demonstrates the practical importance of the formal process.

Sandia National Labs has been investigating concepts for high power lasers pumped directly by fission energy. The direct pumping of laser media with fission fragments offers the potential advantages of scaling to high powers and very long run times in a compact, self powered system. To investigate the potential of this concept, extensive experiments have been conducted in the Annular Core Research Reactor (ACRR) and the Sandia Pulsed Reactor (SPR-III). These experiments include laser physics tests, radiation effects tests on optical materials, and experiments to examine the scaling of reactor pumped lasers to high powers. The SPR-III is a U-10%Mo fast burst reactor which is used for laser physics experiments. SPR-III is capable of 70 to 1500 {mu}s FWHM pulses generating up to several kW/cc excitation in a liter size laser cavity. The pulse widths greater than a few hundred microseconds are achieved using a pulse stretcher consisting of gram amounts of fissile material surrounded by moderator. The ACRR is a UO{sub 2}BeO fueled epithermal reactor which is used for larger volume scaling and beam quality experiments. ACRR operates in both steady state and pulsed modes with pulse widths of 7 to 250 ms resulting in excitation rates of {approximately}2 to 100 W/cc in excitation volumes of up to 50 1. Experimental configurations on both reactors have included central cavity and external cavity locations. The experiments on SPR-III have defined optimum conditions for efficient reactor pumping of rare gas lasers. This information has been used to define scaling experiments now in progress in the ACRR.

The safety and security of foreign nuclear facilities is an important topic for intelligence services. This has been made more important by the breakup of the Former Soviet Union. The major requirement of intelligence analysts is rapid information retrieval after the report of an incident at a foreign facility. Sandia National Laboratories is developing a GIS-based Energy Intelligence Information System (EIIS) to help analysts at The Office of Energy Intelligence of the Department of Energy formulate a response to a nuclear incident. The Vital Issues process was used to determine which information might be the most important to collect. Joint Applications Design and prototyping sessions were held to establish EIIS requirements and refine the user interface. EIIS was built to access any point on the globe or to move directly to a site, facility, or city. The EIIS version 1.0 concentrates on commercial reactors, version 2.0 will include other nuclear fuel cycle sites and release 3.0 will include waste and disposal information. The system runs on a SUN workstation using ARC/INFO{trademark} and Informix as the RDBMS. The map system relies upon the Digital Chart of the World from the Defense Mapping Agency.

Abstract not provided.