Publications

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The Arsenic Water Technology Partnership (AWTP) program is a multi-year program funded by a congressional appropriation through the Department of Energy to develop and test innovative technologies that have the potential to reduce the costs of arsenic removal from drinking water. The AWTP members include Sandia National Laboratories, the American Water Works Association (Awwa) Research Foundation and WERC (A Consortium for Environmental Education and Technology Development). The program is designed to move technologies from bench-scale tests to field demonstrations. The Awwa Research Foundation is managing bench-scale research programs; Sandia National Laboratories is conducting the pilot demonstration program and WERC will evaluate the economic feasibility of the technologies investigated and conduct technology transfer activities. The objective of the Sandia Arsenic Treatment Technology Demonstration project (SATTD) is the field demonstration testing of both commercial and innovative technologies. The scope for this work includes: (1) Identification of sites for pilot demonstrations; (2) Accelerated identification of candidate technologies through Vendor Forums, proof-of-principle laboratory and local pilot-scale studies, collaboration with the Awwa Research Foundation bench-scale research program and consultation with relevant advisory panels; and (3) Pilot testing multiple technologies at several sites throughout the country, gathering information on: (a) Performance, as measured by arsenic removal; (b) Costs, including capital and Operation and Maintenance (O&M) costs; (c) O&M requirements, including personnel requirements, and level of operator training; and (d) Waste residuals generation. The New Mexico Environment Department has identified over 90 public water systems that currently exceed the 10 {micro}g/L MCL for arsenic. The Sandia Arsenic Treatment Technology Demonstration project is currently operating pilots at three sites in New Mexico. The cities of Socorro, Anthony, and Rio Rancho vary in population, water chemistry, and source of arsenic. Figure 1 shows the locations of each city. The following pages summarize the work being performed at each site. At each site, the owners (e.g. city utility) provide access to the site, water, electricity, means to discharge treated water, and daily operational checks. Daily checks include filling out a logsheet with information on the flow rates, pressure drops, flow adjustments (when needed), and notification of Sandia personnel if a leak is present. Sandia owns all equipment and is responsible for the disposal of spent media and other waste streams. Sandia also performs all field tests and collects water samples for laboratory analysis.

We present theoretical performance estimates for nanotube optoelectronic devices under bias. Current-voltage characteristics of illuminated nanotube p-n junctions are calculated using a self-consistent nonequilibrium Green's function approach. Energy conversion rates reaching tens of percent are predicted for incident photon energies near the band gap energy. In addition, the energy conversion rate increases as the diameter of the nanotube is reduced, even though the quantum efficiency shows little dependence on nanotube radius. These results indicate that the quantum efficiency is not a limiting factor for use of nanotubes in optoelectronics.

Tabu search is one of the most effective heuristics for locating high-quality solutions to a diverse array of NP-hard combinatorial optimization problems. Despite the widespread success of tabu search, researchers have a poor understanding of many key theoretical aspects of this algorithm, including models of the high-level run-time dynamics and identification of those search space features that influence problem difficulty. We consider these questions in the context of the job-shop scheduling problem (JSP), a domain where tabu search algorithms have been shown to be remarkably effective. Previously, we demonstrated that the mean distance between random local optima and the nearest optimal solution is highly correlated with problem difficulty for a well-known tabu search algorithm for the JSP introduced by Taillard. In this paper, we discuss various shortcomings of this measure and develop a new model of problem difficulty that corrects these deficiencies. We show that Taillard's algorithm can be modeled with high fidelity as a simple variant of a straightforward random walk. The random walk model accounts for nearly all of the variability in the cost required to locate both optimal and sub-optimal solutions to random JSPs, and provides an explanation for differences in the difficulty of random versus structured JSPs. Finally, we discuss and empirically substantiate two novel predictions regarding tabu search algorithm behavior. First, the method for constructing the initial solution is highly unlikely to impact the performance of tabu search. Second, tabu tenure should be selected to be as small as possible while simultaneously avoiding search stagnation; values larger than necessary lead to significant degradations in performance.

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Contaminant dispersal models for use at scales ranging from meters to miles are widely used for planning sensor locations, first-responder actions for release scenarios, etc. and are constantly being improved. Applications range from urban contaminant dispersal to locating buried targets from an exhaust signature. However, these models need detailed data for model improvement and validation. A small Sandia National Laboratories Laboratory Directed Research and Development (LDRD) program was funded in FY04 to examine the feasibility and usefulness of a scale-model capability for quantitative characterization of flow and contaminant dispersal in complex environments. This report summarizes the work performed in that LDRD. The basics of atmospheric dispersion and dispersion modeling are reviewed. We examine the need for model scale data, and the capability of existing model test methods. Currently, both full-scale and model scale experiments are performed in order to collect validation data for numerical models. Full-scale experiments are expensive, are difficult to repeat, and usually produce relatively sparse data fields. Model scale tests often employ wind tunnels, and the data collected is, in many cases, derived from single point measurements. We review the scaling assumptions and methods that are used to relate model and full scale flows. In particular, we examine how liquid flows may be used to examine the process of atmospheric dispersion. The scaling between liquid and gas flows is presented. Use of liquid as the test fluid has some advantages in terms of achieving fully turbulent Reynolds numbers and in seeding the flow with neutrally buoyant tracer particles. In general, using a liquid flow instead of a gas flow somewhat simplifies the use of full field diagnostics, such as Particle Image Velocimetry and Laser Induced Fluorescence. It is also possible to create stratified flows through mixtures of fluids (e.g., water, alcohol, and brine). Lastly, we describe our plan to create a small prototype water flume for the modeling of stratified atmospheric flows around complex objects. The incoming velocity profile could be tailored to produce a realistic atmospheric boundary layer for flow-in-urban-canyon measurements. The water tunnel would allow control of stratification to produce, for example, stable and unstable atmospheric conditions. Models ranging from a few buildings to cityscapes would be used as the test section. Existing noninvasive diagnostics would be applied, including particle image velocimetry for detailed full-field velocity measurement, and laser induced fluorescence for noninvasive concentration measurement. This scale-model facility will also be used as a test-bed for data acquisition and model testing related to the inverse problem, i.e., determination of source location from distributed, sparse measurement locations. In these experiments the velocity field would again be measured and data from single or multiple concentration monitors would be used to locate the continuous or transient source.

We present a model for optimizing the placement of sensors in municipal water networks to detect maliciously injected contaminants. An optimal sensor configuration minimizes the expected fraction of the population at risk. We formulate this problem as a mixed-integer program, which can be solved with generally available solvers. We find optimal sensor placements for three test networks with synthetic risk and population data. Our experiments illustrate that this formulation can be solved relatively quickly and that the predicted sensor configuration is relatively insensitive to uncertainties in the data used for prediction.

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As Sandia looks toward petaflops computing and other advanced architectures, it is necessary to provide a programming environment that can exploit this additional computing power while supporting reasonable development time for applications. Thus, they evaluate the Partitioned Global Address Space (PGAS) programming model as implemented in Unified Parallel C (UPC) for its applicability. They report on their experiences in implementing sorting and minimum spanning tree algorithms on a test system, a Cray T3e, with UPC support. They describe several macros that could serve as language extensions and several building-block operations that could serve as a foundation for a PGAS programming library. They analyze the limitations of the UPC implementation available on the test system, and suggest improvements necessary before UPC can be used in a production environment.

Our research explores the feasibility of using communication theory, error control (EC) coding theory specifically, for quantitatively modeling the protein translation initiation mechanism. The messenger RNA (mRNA) of Escherichia coli K-12 is modeled as a noisy (errored), encoded signal and the ribosome as a minimum Hamming distance decoder, where the 16S ribosomal RNA (rRNA) serves as a template for generating a set of valid codewords (the codebook). We tested the E. coli based coding models on 5′ untranslated leader sequences of prokaryotic organisms of varying taxonomical relation to E. coli including: Salmonella typhimurium LT2, Bacillus subtilis, and Staphylococcus aureus Mu50. The model identified regions on the 5′ untranslated leader where the minimum Hamming distance values of translated mRNA sub-sequences and non-translated genomic sequences differ the most. These regions correspond to the Shine-Dalgarno domain and the non-random domain. Applying the EC coding-based models to B. subtilis, and S. aureus Mu50 yielded results similar to those for E. coli K-12. Contrary to our expectations, the behavior of S. typhimurium LT2, the more taxonomically related to E. coli, resembled that of the non-translated sequence group. © 2004 Elsevier Ireland Ltd. All rights reserved.

An improved gas-damping model for the out-of-plane motion of a near-substrate microbeam is developed based on the Reynolds equation (RE). A boundary condition for the RE is developed that relates the pressure at the beam edge to the beam motion. The coefficients in this boundary condition are determined from Navier-Stokes slip-jump (NSSJ) simulations for small slip lengths (relative to the gap height) and from direct simulation Monte Carlo (DSMC) molecular gas dynamics simulations for larger slip lengths. This boundary condition significantly improves the accuracy of the RE when the microbeam width is only slightly greater than the gap height between the microbeam and the substrate. The improved RE model is applied to microbeams fabricated using the SUMMiT V process. © 2004 IEEE.

The SSP is a hardware implementation of a subset of the JVM for use in high consequence embedded applications. In this context, a majority of the activities belonging to class loading, as it is defined in the specification of the JVM, can be performed statically. Static class loading has the net result of dramatically simplifying the design of the SSP as well as increasing its performance. Due to the high consequence nature of its applications, strong evidence must be provided that all aspects of the SSP have been implemented correctly. This includes the class loader. This article explores the possibility of formally verifying a class loader for the SSP implemented in the strategic programming language TL. Specifically, an implementation of the core activities of an abstract class loader is presented and its verification in ACL2 is considered.

The mathematical and physical foundations and domain of applicability of Sandia's GeoModel are presented along with descriptions of the source code and user instructions. The model is designed to be used in conventional finite element architectures, and (to date) it has been installed in five host codes without requiring customizing the model subroutines for any of these different installations. Although developed for application to geological materials, the GeoModel actually applies to a much broader class of materials, including rock-like engineered materials (such as concretes and ceramics) and even to metals when simplified parameters are used. Nonlinear elasticity is supported through an empirically fitted function that has been found to be well-suited to a wide variety of materials. Fundamentally, the GeoModel is a generalized plasticity model. As such, it includes a yield surface, but the term 'yield' is generalized to include any form of inelastic material response including microcrack growth and pore collapse. The geomodel supports deformation-induced anisotropy in a limited capacity through kinematic hardening (in which the initially isotropic yield surface is permitted to translate in deviatoric stress space to model Bauschinger effects). Aside from kinematic hardening, however, the governing equations are otherwise isotropic. The GeoModel is a genuine unification and generalization of simpler models. The GeoModel can employ up to 40 material input and control parameters in the rare case when all features are used. Simpler idealizations (such as linear elasticity, or Von Mises yield, or Mohr-Coulomb failure) can be replicated by simply using fewer parameters. For high-strain-rate applications, the GeoModel supports rate dependence through an overstress model.

An integrated system for the fusion of product and process sensors and controls for production of flat glass was envisioned, having as its objective the maximization of throughput and product quality subject to emission limits, furnace refractory wear, and other constraints. Although the project was prematurely terminated, stopping the work short of its goal, the tasks that were completed show the value of the approach and objectives. Though the demonstration was to have been done on a flat glass production line, the approach is applicable to control of production in the other sectors of the glass industry. Furthermore, the system architecture is also applicable in other industries utilizing processes in which product uniformity is determined by ability to control feed composition, mixing, heating and cooling, chemical reactions, and physical processes such as distillation, crystallization, drying, etc. The first phase of the project, with Visteon Automotive Systems as industrial partner, was focused on simulation and control of the glass annealing lehr. That work produced the analysis and computer code that provide the foundation for model-based control of annealing lehrs during steady state operation and through color and thickness changes. In the second phase of the work, with PPG Industries as the industrial partner, the emphasis was on control of temperature and combustion stoichiometry in the melting furnace, to provide a wider operating window, improve product yield, and increase energy efficiency. A program of experiments with the furnace, CFD modeling and simulation, flow measurements, and sensor fusion was undertaken to provide the experimental and theoretical basis for an integrated, model-based control system utilizing the new infrastructure installed at the demonstration site for the purpose. In spite of the fact that the project was terminated during the first year of the second phase of the work, the results of these first steps toward implementation of model-based control were sufficient to demonstrate the value of the approach to improving the productivity of glass manufacture.

Given pre-existing Groundwater Modeling System (GMS) models of the Horonobe Underground Research Laboratory (URL) at both the regional and site scales, this work performs an example uncertainty analysis for performance assessment (PA) applications. After a general overview of uncertainty and sensitivity analysis techniques, the existing GMS sitescale model is converted to a PA model of the steady-state conditions expected after URL closure. This is done to examine the impact of uncertainty in site-specific data in conjunction with conceptual model uncertainty regarding the location of the Oomagari Fault. In addition, a quantitative analysis of the ratio of dispersive to advective forces, the F-ratio, is performed for stochastic realizations of each conceptual model. All analyses indicate that accurate characterization of the Oomagari Fault with respect to both location and hydraulic conductivity is critical to PA calculations. This work defines and outlines typical uncertainty and sensitivity analysis procedures and demonstrates them with example PA calculations relevant to the Horonobe URL.

One problem facing today's nuclear power industry is flow-accelerated corrosion and erosion in pipe elbows. The Korean Atomic Energy Research Institute (KAERI) is performing experiments in their Flow-Accelerated Corrosion (FAC) test loop to better characterize these phenomena, and develop advanced sensor technologies for the condition monitoring of critical elbows on a continuous basis. In parallel with these experiments, Sandia National Laboratories is performing Computational Fluid Dynamic (CFD) simulations of the flow in one elbow of the FAC test loop. The simulations are being performed using the FLUENT commercial software developed and marketed by Fluent, Inc. The model geometry and mesh were created using the GAMBIT software, also from Fluent, Inc. This report documents the results of the simulations that have been made to date; baseline results employing the RNG k-e turbulence model are presented. The predicted value for the diametrical pressure coefficient is in reasonably good agreement with published correlations. Plots of the velocities, pressure field, wall shear stress, and turbulent kinetic energy adjacent to the wall are shown within the elbow section. Somewhat to our surprise, these indicate that the maximum values of both wall shear stress and turbulent kinetic energy occur near the elbow entrance, on the inner radius of the bend. Additional simulations were performed for the same conditions, but with the RNG k-e model replaced by either the standard k-{var_epsilon}, or the realizable k-{var_epsilon} turbulence model. The predictions using the standard k-{var_epsilon} model are quite similar to those obtained in the baseline simulation. However, with the realizable k-{var_epsilon} model, more significant differences are evident. The maximums in both wall shear stress and turbulent kinetic energy now appear on the outer radius, near the elbow exit, and are {approx}11% and 14% greater, respectively, than those predicted in the baseline calculation; secondary maxima in both quantities still occur near the elbow entrance on the inner radius. Which set of results better reflects reality must await experimental corroboration. Additional calculations demonstrate that whether or not FLUENT's radial equilibrium pressure distribution option is used in the PRESSURE OUTLET boundary condition has no significant impact on the flowfield near the elbow. Simulations performed with and without the chemical sensor and associated support bracket that were present in the experiments demonstrate that the latter have a negligible influence on the flow in the vicinity of the elbow. The fact that the maxima in wall shear stress and turbulent kinetic energy occur on the inner radius is therefore not an artifact of having introduced the sensor into the flow.

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This document summarizes the equations and applications associated with the photovoltaic array performance model developed at Sandia National Laboratories over the last twelve years. Electrical, thermal, and optical characteristics for photovoltaic modules are included in the model, and the model is designed to use hourly solar resource and meteorological data. The versatility and accuracy of the model has been validated for flat-plate modules (all technologies) and for concentrator modules, as well as for large arrays of modules. Applications include system design and sizing, 'translation' of field performance measurements to standard reporting conditions, system performance optimization, and real-time comparison of measured versus expected system performance.

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ITS (Integrated Tiger Series) permits a state-of-the-art Monte Carlo solution of linear time-integrated coupled electron/photon radiation transport problems with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. ITS allows designers to predict product performance in radiation environments.

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The Z machine at Sandia National Laboratories (SNL) is the world's largest and most powerful laboratory X-ray source. The Z Refurbishment Project (ZR) is presently underway to provide an improved precision, more shot capacity, and a higher current capability. The ZR upgrade has a total output current requirement of at least 26 MA for a 100-ns standard Z-pinch load. To accomplish this with minimal impact on the surrounding hardware, the 60 high-energy discharge capacitors in each of the existing 36 Marx generators must be replaced with identical size units but with twice the capacitance. Before the six-month shut down and transition from Z to ZR occurs, 2500 of these capacitors will be delivered. We chose to undertake an ambitious vendor qualification program to reduce the risk of not meeting ZR performance goals, to encourage the pulsed-power industry to revisit the design and development of high- energy discharge capacitors, and to meet the cost and delivery schedule within the ZR project plans. Five manufacturers were willing to fabricate and sell SNL samples of six capacitors each to be evaluated. The 8000-shot qualification test phase of the evaluation effort is now complete. This paper summarizes how the 0.279 x 0.356 x 0.635-m (11 x 14 x 25-in) stainless steel can, Scyllac-style insulator bushing, 2.65-{micro}F, < 30-nH, 100-kV, 35%-reversal capacitor lifetime specifications were determined, briefly describes the nominal 260-kJ test facility configuration, presents the test results of the most successful candidates, and discusses acceptance testing protocols that balance available resources against performance, cost, and schedule risk. We also summarize the results of our accelerated lifetime testing of the selected General Atomics P/N 32896 capacitor. We have completed lifetime tests with twelve capacitors at 100 kV and with fourteen capacitors at 110-kV charge voltage. The means of the fitted Weibull distributions for these two cases are about 17,000 and 10,000 shots, respectively. As a result of this effort plus the rigorous vendor testing prior to shipping, we are confident in the high reliability of these capacitors and have acquired information pertaining to their lifetime dependence on the operating voltage. One result of the analysis is that, for these capacitors, lifetime scales inversely with voltage to the 6.28 {+-} 0.91 power, over this 100 to 110-kV voltage range. Accepting the assumptions leading to this outcome allows us to predict the overall ZR system Marx generator capacitor reliability at the expected lower operating voltage of about 85 kV.

In SAND report 2004-1617, we outline a method for edge-based tetrahedral subdivision that does not rely on saving state or communication to produce compatible tetrahedralizations. This report analyzes the performance of the technique by characterizing (a) mesh quality, (b) execution time, and (c) traits of the algorithm that could affect quality or execution time differently for different meshes. It also details the method used to debug the several hundred subdivision templates that the algorithm relies upon. Mesh quality is on par with other similar refinement schemes and throughput on modern hardware can exceed 600,000 output tetrahedra per second. But if you want to understand the traits of the algorithm, you have to read the report!

The Integrated TIGER Series (ITS) is a software package that solves coupled electron-photon transport problems. ITS performs analog photon tracking for energies between 1 keV and 1 GeV. Unlike its deterministic counterpart, the Monte Carlo calculations of ITS do not require a memory-intensive meshing of phase space; however, its solutions carry statistical variations. Reducing these variations is heavily dependent on runtime. Monte Carlo simulations must therefore be both physically accurate and computationally efficient. Compton scattering is the dominant photon interaction above 100 keV and below 5-10 MeV, with higher cutoffs occurring in lighter atoms. In its current model of Compton scattering, ITS corrects the differential Klein-Nishina cross sections (which assumes a stationary, free electron) with the incoherent scattering function, a function dependent on both the momentum transfer and the atomic number of the scattering medium. While this technique accounts for binding effects on the scattering angle, it excludes the Doppler broadening the Compton line undergoes because of the momentum distribution in each bound state. To correct for these effects, Ribbefor's relativistic impulse approximation (IA) will be employed to create scattering cross section differential in both energy and angle for each element. Using the parameterizations suggested by Brusa et al., scattered photon energies and angle can be accurately sampled at a high efficiency with minimal physical data. Two-body kinematics then dictates the electron's scattered direction and energy. Finally, the atomic ionization is relaxed via Auger emission or fluorescence. Future work will extend these improvements in incoherent scattering to compounds and to adjoint calculations.

A Mueller matrix imaging polarimeter is used to acquire polarization-sensitive images of seven different manmade samples in multiple scattering geometries. Successive Mueller matrix images of a sample with changing incidence and scatter angles are used to develop a Mueller matrix bidirectional reflectance distribution function for the sample in one plane of measurement. The Mueller matrix bidirectional reflectance distribution functions are compared, and patterns are noted. The most significant data for the scattering samples measured occurs along the diagonal of the respective Mueller matrices, indicating significant depolarization effects. Reduced depolarization data in the form of the average degree of polarization (of exiting light) for each sample is examined as a function of changing scattering geometry. Five of seven manmade samples exhibit an inverted Gaussian profile of depolarization with changing scattering geometry, the shape of which may prove useful for measuring sample properties (e.g. roughness) and for classifying or categorizing samples in a remote sensing scheme. Depolarization differences for each sample in response to changing incident polarization states are also examined, and a new metric, the degree of polarization surface, has been developed to visualize all such data simultaneously.

This report provides soil evaluation and characterization testing for the submarine bases at Kings Bay, Georgia, and Bangor, Washington, using triaxial testing at high confining pressures with different moisture contents. In general, the samples from the Bangor and Kings Bay sites appeared to be stronger than a previously used reference soil. Assuming the samples of the material were representative of the material found at the sites, they should be adequate for use in the planned construction. Since soils can vary greatly over even a small site, a soil specification for the construction contractor would be needed to insure that soil variations found at the site would meet or exceed the requirements. A suggested specification for the Bangor and Kings Bay soils was presented based on information gathered from references plus data obtained from this study, which could be used as a basis for design by the construction contractor.

This is a basic documentation explaining how to use the SANDmath macros with a LATEX 2{var_epsilon} document pertaining to the SANDreport class.

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The need for fresh water has increased exponentially during the last several decades due to the continuous growth of human population and industrial and agricultural activities. Yet existing resources are limited often because of their high salinity. This unfavorable situation requires the development of new, long-term strategies and alternative technologies for desalination of saline waters presently not being used to supply the population growth occurring in arid regions. We have developed a novel environmentally friendly method for desalinating inland brackish waters. This process can be applied to either brackish ground water or produced waters (i.e., coal-bed methane or oil and gas produced waters). Using a set of ion exchange and sorption materials, our process effectively removes anions and cations in separate steps. The ion exchange materials were chosen because of their specific selectivity for ions of interest, and for their ability to work in the temperature and pH regions necessary for cost and energy effectiveness. For anion exchange, we have focused on hydrotalcite (HTC), a layered hydroxide similar to clay in structure. For cation exchange, we have developed an amorphous silica material that has enhanced cation (in particular Na{sup +}) selectivity. In the case of produced waters with high concentrations of Ca{sup 2+}, a lime softening step is included.

Conclusions of this paper are: (1) Adsorption/desorption on bulk unmodified zeolites showed isoprene adsorbed by zeolite-L and n-pentane adsorbed by zeolite-Y and ZSM-5; (2) Bulk carbonization is used to passivate zeolite activity toward organic adsorption/decomposition; (3) Based on the bulk modified zeolite separation results, we have determined that the MFI type has the most potential for isoprene enrichment; (4) Modified MFI type membranes are jointly made by Sandia and the Univ. of Colorado. Separation experiments are performed by Goodyear Chemical; (5) Isoprene/n-pentane separations have been demonstrated by using both zeolite membranes and modified bulk zeolites at various temperatures on the Goodyear Pilot-scale unit; and (6) Target zeolite membrane separations values of 6.7% isoprene enrichment have been established by economic analysis calculations by Burns & McDonnell.

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It is shown that for any material or structural model expressible as a Masing model, there exists a unique parallel-series (displacement-based) Iwan system that characterizes that model as a function of displacement history. This poses advantages both in terms of more convenient force evaluation in arbitrary deformation histories as well as in terms of model inversion. Characterization as an Iwan system is demonstrated through the inversion of the Ramberg-Osgood model, a force(stress)-based material model that is not explicitly invertible. An implication of the inversion process is that direct, rigorous comparisons of different Masing models, regardless of the ability to invert their constitutive relationship, can be achieved through the comparison of their associated Iwan distribution densities.

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This report summarizes numerical analyses conducted to assess the relative importance on penetration depth calculations of rock constitutive model physics features representing the presence of microscale flaws such as porosity and networks of microcracks and rock mass structural features. Three-dimensional, nonlinear, transient dynamic finite element penetration simulations are made with a realistic geomaterial constitutive model to determine which features have the most influence on penetration depth calculations. A baseline penetration calculation is made with a representative set of material parameters evaluated from measurements made from laboratory experiments conducted on a familiar sedimentary rock. Then, a sequence of perturbations of various material parameters allows an assessment to be made of the main penetration effects. A cumulative probability distribution function is calculated with the use of an advanced reliability method that makes use of this sensitivity database, probability density functions, and coefficients of variation of the key controlling parameters for penetration depth predictions. Thus the variability of the calculated penetration depth is known as a function of the variability of the input parameters. This simulation modeling capability should impact significantly the tools that are needed to design enhanced penetrator systems, support weapons effects studies, and directly address proposed HDBT defeat scenarios.

Pioneering x-ray imaging has been undertaken on a number of AWE's and Sandia National Laboratories radiation effects x-ray simulators. These simulators typically yield a single very short (<50ns) pulse of high-energy (MeV endpoint energy bremsstrahlung) x-ray radiation with doses in the kilorad (krad(Si)) region. X-ray source targets vary in size from 2 to 25cm diameter, dependent upon the particular simulator. Electronic imaging of the source x-ray emission under dynamic conditions yields valuable information upon how the simulator is performing. The resultant images are of interest to the simulator designer who may configure new x-ray source converter targets and diode designs. The images can provide quantitative information about machine performance during radiation effects testing of components under active conditions. The effects testing program is a valuable interface for validation of high performance computer codes and models for the radiation effects community. A novel high-energy x-ray imaging spectrometer is described whereby the spectral energy (0.1 to 2.5MeV) profile may be discerned from the digitally recorded and viewable images via a pinhole/scintillator/CCD imaging system and knowledge of the filtration parameters. Unique images, analysis and a preliminary evaluation of the capability of the spectrometer are presented. Further, a novel time resolved imaging system is described that captures a sequence of high spatial resolution temporal images, with zero interframe time, in the nanosecond timeframe, of our source x-rays.

One of the most important types of data in the National Nuclear Security Administration (NNSA) Ground-Based Nuclear Explosion Monitoring Research and Engineering (GNEM R&E) Knowledge Base (KB) is parametric grid (PG) data. PG data can be used to improve signal detection, signal association, and event discrimination, but so far their greatest use has been for improving event location by providing ground-truth-based corrections to travel-time base models. In this presentation we discuss the latest versions of the complete suite of Knowledge Base PG tools developed by NNSA to create, access, manage, and view PG data. The primary PG population tool is the Knowledge Base calibration integration tool (KBCIT). KBCIT is an interactive computer application to produce interpolated calibration-based information that can be used to improve monitoring performance by improving precision of model predictions and by providing proper characterizations of uncertainty. It is used to analyze raw data and produce kriged correction surfaces that can be included in the Knowledge Base. KBCIT not only produces the surfaces but also records all steps in the analysis for later review and possible revision. New features in KBCIT include a new variogram autofit algorithm; the storage of database identifiers with a surface; the ability to merge surfaces; and improved surface-smoothing algorithms. The Parametric Grid Library (PGL) provides the interface to access the data and models stored in a PGL file database. The PGL represents the core software library used by all the GNEM R&E tools that read or write PGL data (e.g., KBCIT and LocOO). The library provides data representations and software models to support accurate and efficient seismic phase association and event location. Recent improvements include conversion of the flat-file database (FDB) to an Oracle database representation; automatic access of station/phase tagged models from the FDB during location; modification of the core geometric data representations; a new multimodel representation for combining separate seismic data models that partially overlap; and a port of PGL to the Microsoft Windows platform. The Data Manager (DM) tool provides access to PG data for purposes of managing the organization of the generated PGL file database, or for perusing the data for visualization and informational purposes. It is written as a graphical user interface (GUI) that can directly access objects stored in any PGL file database and display it in an easily interpreted textual or visual format. New features include enhanced station object processing; low-level conversion to a new core graphics visualization library, the visualization toolkit (VTK); additional visualization support for most of the PGL geometric objects; and support for the Environmental Systems Research Institute (ESRI) shape files (which are used to enhance the geographical context during visualization). The Location Object-Oriented (LocOO) tool computes seismic event locations and associated uncertainty based on travel time, azimuth, and slowness observations. It uses a linearized least-squares inversion algorithm (the Geiger method), enhanced with Levenberg-Marquardt damping to improve performance in highly nonlinear regions of model space. LocOO relies on PGL for all predicted quantities and is designed to fully exploit all the capabilities of PGL that are relevant to seismic event location. New features in LocOO include a redesigned internal architecture implemented to enhance flexibility and to support simultaneous multiple event location. Database communication has been rewritten using new object-relational features available in Oracle 9i.

To make use of some portions of the National Nuclear Security Administration (NNSA) Knowledge Base (KB) for which no current operational monitoring applications were available, Sandia National Laboratories have developed a set of prototype regional analysis tools (MatSeis, EventID Tool, CodaMag Tool, PhaseMatch Tool, Dendro Tool, Infra Tool, etc.), and we continue to maintain and improve these. Individually, these tools have proven effective in addressing specific monitoring tasks, but collectively their number and variety tend to overwhelm KB users, so we developed another application - the KB Navigator - to launch the tools and facilitate their use for real monitoring tasks. The KB Navigator is a flexible, extensible java application that includes a browser for KB data content, as well as support to launch any of the regional analysis tools. In this paper, we will discuss the latest versions of KB Navigator and the regional analysis tools, with special emphasis on the new overarching inter-tool communication methodology that we have developed to make the KB Navigator and the tools function together seamlessly. We use a peer-to-peer communication model, which allows any tool to communicate with any other. The messages themselves are passed as serialized XML, and the conversion from Java to XML (and vice versa) is done using Java Architecture for XML Binding (JAXB).

TrackEye is a film digitization and target tracking system that offers the potential for quantitatively measuring the dynamic state variables (e.g., absolute and relative position, orientation, linear and angular velocity/acceleration, spin rate, trajectory, angle of attack, etc.) for moving objects using captured single or dual view image sequences. At the heart of the system is a set of tracking algorithms that automatically find and quantify the location of user selected image details such as natural test article features or passive fiducials that have been applied to cooperative test articles. This image position data is converted into real world coordinates and rates with user specified information such as the image scale and frame rate. Though tracking methods such as correlation algorithms are typically robust by nature, the accuracy and suitability of each TrackEye tracking algorithm is in general unknown even under good imaging conditions. The challenges of optimal algorithm selection and algorithm performance/measurement uncertainty are even more significant for long range tracking of high-speed targets where temporally varying atmospheric effects degrade the imagery. This paper will present the preliminary results from a controlled test sequence used to characterize the performance of the TrackEye tracking algorithm suite.

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The West Hackberry salt dome, in southwestern Louisiana, is one of four underground oil-storage facilities managed by the U. S. Department of Energy Strategic Petroleum Reserve (SPR) Program. Sandia National Laboratories, as the geotechnical advisor to the SPR, conducts site-characterization investigations and other longer-term geotechnical and engineering studies in support of the program. This report describes the conversion of two-dimensional geologic interpretations of the West Hackberry site into three-dimensional geologic models. The new models include the geometry of the salt dome, the surrounding sedimentary layers, mapped faults, and a portion of the oil storage caverns at the site. This work provides a realistic and internally consistent geologic model of the West Hackberry site that can be used in support of future work.

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The breacher's training aid described in this report was designed to simulate features of magazine and steel-plate doors. The training aid enables breachers to practice using their breaching tools on components that they may encounter when attempting to enter a facility. Two types of fixtures were designed and built: (1) a large fixture incorporates simulated hinges, hasps, lock shrouds, and pins, and (2) a small fixture simulates the cross section of magazine and steel-plate doors. The small fixture consists of steel plates on either side of a structural member, such as an I-beam. The report contains detailed descriptions and photographs of the training aids, assembly instructions, and drawings.

Approximate formulas are constructed and numerical simulations are carried out for electric field derivative probes that have the form of flush mounted monopoles. Effects such as rounded edges are included. A method is introduced to make results from two-dimensional conformal mapping analyses accurately apply to the three-dimensional axisymmetric probe geometry

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The need for a Combustion and Melting Research Facility focused on the solution of glass manufacturing problems common to all segments of the glass industry was given high priority in the earliest version of the Glass Industry Technology Roadmap (Eisenhauer et al., 1997). Visteon Glass Systems and, later, PPG Industries proposed to meet this requirement, in partnership with the DOE/OIT Glass Program and Sandia National Laboratories, by designing and building a research furnace equipped with state-of-the-art diagnostics in the DOE Combustion Research Facility located at the Sandia site in Livermore, CA. Input on the configuration and objectives of the facility was sought from the entire industry by a variety of routes: (1) through a survey distributed to industry leaders by GMIC, (2) by conducting an open workshop following the OIT Glass Industry Project Review in September 1999, (3) from discussions with numerous glass engineers, scientists, and executives, and (4) during visits to glass manufacturing plants and research centers. The recommendations from industry were that the melting tank be made large enough to reproduce the essential processes and features of industrial furnaces yet flexible enough to be operated in as many as possible of the configurations found in industry as well as in ways never before attempted in practice. Realization of these objectives, while still providing access to the glass bath and combustion space for optical diagnostics and measurements using conventional probes, was the principal challenge in the development of the tank furnace design. The present report describes a facility having the requirements identified as important by members of the glass industry and equipped to do the work that the industry recommended should be the focus of research. The intent is that the laboratory would be available to U.S. glass manufacturers for collaboration with Sandia scientists and engineers on both precompetitive basic research and the solution of proprietary glass production problems. As a consequence of the substantial increase in scale and scope of the initial furnace concept in response to industry recommendations, constraints on funding of industrial programs by DOE, and reorientation of the Department's priorities, the OIT Glass Program is unable to provide the support for construction of such a facility. However, it is the present investigators' hope that a group of industry partners will emerge to carry the project forward, taking advantage of the detailed furnace design presented in this report. The engineering, including complete construction drawings, bill of materials, and equipment specifications, is complete. The project is ready to begin construction as soon as the quotations are updated. The design of the research melter closely follows the most advanced industrial practice, firing by natural gas with oxygen. The melting area is 13 ft x 6 ft, with a glass depth of 3 ft and an average height in the combustion space of 3 ft. The maximum pull rate is 25 tons/day, ranging from 100% batch to 100% cullet, continuously fed, with variable batch composition, particle size distribution, and raft configuration. The tank is equipped with bubblers to control glass circulation. The furnace can be fired in three modes: (1) using a single large burner mounted on the front wall, (2) by six burners in a staggered/opposed arrangement, three in each breast wall, and (3) by down-fired burners mounted in the crown in any combination with the front wall or breast-wall-mounted burners. Horizontal slots are provided between the tank blocks and tuck stones and between the breast wall and skewback blocks, running the entire length of the furnace on both sides, to permit access to the combustion space and the surface of the glass for optical measurements and sampling probes. Vertical slots in the breast walls provide additional access for measurements and sampling. The furnace and tank are to be fully instrumented with standard measuring equipment, such as flow meters, thermocouples, continuous gas composition analyzers, optical pyrometers, and a video camera. The output from the instruments is to be continuously recorded and simultaneously made available to other researchers via the Internet. A unique aspect of the research facility would be its access to the expertise in optical measurements in flames and high temperature reacting flows residing in the Sandia Combustion Research Facility. Development of new techniques for monitoring and control of glass melting would be a major focus of the work. The lab would be equipped with conventional and laser light sources and detectors for optical measurements of gas temperature, velocity, and gaseous species and, using new techniques to be developed in the Research Facility itself, glass temperature and glass composition.

Transmission electron microscope (TEM) tomography provides three-dimensional structural information from tilt series with nanoscale resolution. We have collected TEM projection data sets to study the internal structure of photocatalytic nanoparticles. Multiple cross-sectional slices of the nanoparticles are reconstructed using an algebraic reconstruction technique (ART) and then assembled to form a 3D rendering of the object. We recently upgraded our TEM with a new sample holder having a tilt range of +/-70{sup o} and have collected tomography data over a range of 125{sup o}. Simulations were performed to study the effects of field-of-view displacement (shift and rotation), limited tilt angle range, hollow (missing) projections, stage angle accuracy, and number of projections on the reconstructed image quality. This paper discusses our experimental and computational approaches, presents some examples of TEM tomography, and considers future directions.

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The magnetic-pressure drive technique allows single-shot measurements of compression isentropes. We have used this method to measure the isentropes in the pressure-volume space of bulk and single-crystal lead, and lead-antimony alloy to {approx}400 kbar. The isentrope pressure-volume curves were found from integration of the experimentally deduced Lagrangian sound speed as a function of particle velocity. A characteristics calculation method was used to convert time-resolved free-surface velocity measurements to corresponding in situ particle-velocity histories, from which the Lagrangian sound speed was determined from the times for samples of different thicknesses to reach the same particle velocity. Use of multiple velocity interferometry probes decreased the uncertainty due to random errors by allowing multiple measurements. Our results have errors of from 4% to 6% in pressure, {approx}1% to 1.5% in volume, depending on the number of measurements, and are consistent with existing isotherm and Hugoniot data and models for lead.

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Relative integrated cross sections are measured for rotationally inelastic scattering of NO({sup 2}{pi}{sub 1/2}), hexapole selected in the upper {Lambda}-doublet level of the ground rotational state (j = 0.5), in collisions with He at a nominal energy of 514 cm{sup -1}. Application of a static electric field E in the scattering region, directed parallel or antiparallel to the relative velocity vector v, allows the state-selected NO molecule to be oriented with either the N end or the O end towards the incoming He atom. Laser-induced fluorescence detection of the final state of the NO molecule is used to determine the experimental steric asymmetry, SA {triple_bond} ({sigma}{sub v}{up_arrow}{down_arrow}{sub E}-{sigma}{sub v}{up_arrow}{up_arrow}{sub E})/({sigma}{sub v}{up_arrow}{down_arrow}{sub E} + {sigma}{sub v}{up_arrow}{up_arrow}{sub E}), which is equal to within a factor of (-1) to the molecular steric effect, S{sub i {yields} f} {triple_bond} ({sigma}{sub He {yields} NO} - {sigma}{sub He {yields} ON})/({sigma}{sub He {yields} NO} + {sigma}{sub He {yields} ON}). The dependence of the integral inelastic cross section on the incoming {lambda}-doublet component is also observed as a function of the final rotational (j{prime}), spin-orbit ({Omega}{prime}), and {Lambda}-doublet ({epsilon}{prime}) state. The measured steric asymmetries are significantly larger than previously observed for NO-Ar scattering, supporting earlier proposals that the repulsive part of the interaction potential is responsible for the steric asymmetry. In contrast to the case of scattering with Ar, the steric asymmetry of NO-He collisions is not very sensitive to the value of {Omega}{prime} . However, the {Lambda}-doublet propensities are very different for [{Omega} = 0.5(F{sub 1}) {yields} {Omega}{prime} = 0.5(F{sub 1})] transitions. Spin-orbit manifold conserving collisions exhibit a propensity for parity conservation at low {Delta}{sub j}, but spin-orbit manifold changing collisions do not show this propensity. In conjunction with the experiments, state-to-state cross sections for scattering of oriented NO({sup 2}{pi}) molecules with He atoms are predicted from close-coupling calculations on restricted coupled-cluster methods including single, double, and noniterated triple excitations [J. Klos, G. Chalasinski, M. T. Berry, R. Bukowski, and S. M. Cybulski, J. Chem. Phys. 112, 2195 (2000)] and correlated electron-pair approximation [M. Yang and M. H. Alexander, J. Chem. Phys. 103, 6973 (1995)] potential energy surfaces. The calculated steric asymmetry S{sub i {yields} f} of the inelastic cross sections at E{sub tr} = 514 cm{sup -1} is in reasonable agreement with that derived from the present experimental measurements for both spin-manifold conserving (F{sub 1} {yields} F{sub 1}) and spin-manifold changing (F{sub 1} {yields} F{sub 2}) collisions, except that the overall sign of the effect is opposite. Additionally, calculated field-free integral cross sections for collisions at E{sub tr} = 508 cm{sup -1} are compared to the experimental data of Joswig et al. [J. Chem. Phys. 85, 1904 (1986)]. Finally, the calculated differential cross section for collision energy E{sub tr} = 491 cm{sup -1} is compared to experimental data of Westley et al. [J. Chem. Phys. 114, 2669 (2001)] for the spin-orbit conserving transition F{sub 1} (j = 0.5) {yields} F{sub 1}f(j{prime} = 3.5).

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At the direction of the Department of Defense Explosives Safety Board (DDESB), a Peer Review Team was established to review the status of development of the risk-based explosives safety siting process and criteria as currently implemented in the software 'Safety Assessment for Explosive Risk (SAFER)' Version 2.1. The objective of the Peer Review Team was to provide an independent evaluation of the components of the SAFER model, the ongoing development of the model and the risk assessment process and criteria. This peer review report addressed procedures; protocols; physical and statistical science algorithms; related documents; and software quality assurance, validation and verification. Overall, the risk-based method in SAFER represents a major improvement in the Department of Defense (DoD) approach to explosives safety management. The DDESB and Risk Based Explosives Safety Criteria Team (RBESCT) have made major strides in developing a methodology, which over time may become a worldwide model. The current status of all key areas of the SAFER code has been logically developed and is defensible. Continued improvement and refinement can be expected as implementation proceeds. A consistent approach to addressing and refining uncertainty in each of the primary areas (probability of event, consequences of event and exposure) will be a very beneficial future activity.

The length scale of stress domain patterns formed at solid surfaces is usually calculated using isotropic elasticity theory. Because this length depends exponentially on elastic constants; deviations between isotropic and anisotropic elasticity can lead to large errors. Another inaccuracy of isotropic elasticity theory is that it neglects the dependence of elastic relaxations on stripe orientation. To remove these inaccuracies; we calculate the energy of striped domain patterns using anisotropic elasticity theory for an extensive set of surfaces encountered in experimental studies of self-assembly. We present experimental and theoretical evidence that elastic anisotropy is large enough to determine the stripe orientation when Pb is deposited on Cu(111). Our analytical and numerical results should be useful for analysis of a broad range of experimental systems.

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The formation of HO{sub 2} in the reactions of C{sub 2}H{sub 5}, n-C{sub 3}H{sub 7}, and i-C{sub 3}H{sub 7} radicals with O{sub 2} is investigated using the technique of laser photolysis/long-path frequency-modulation spectroscopy. The alkyl radicals are formed by 266 nm photolysis of alkyl iodides. The formation of HO{sub 2} from the subsequent reaction of the alkyl radicals with O{sub 2} is followed by infrared frequency-modulation spectroscopy. The concentration of I atoms is simultaneously monitored by direct absorption of a second laser probe on the spin?orbit transition. The measured profiles are compared to a kinetic model taken from time-resolved master-equation results based on previously published ab initio characterizations of the relevant stationary points on the potential-energy surface. The ab initio energies are adjusted to produce agreement with the present experimental data and with available literature studies. The isomer specificity of the present results enables refinement of the model for i-C{sub 3}H{sub 7} + O{sub 2} and improved agreement with experimental measurements of HO{sub 2} production in propane oxidation.

This manual describes the theory behind many of the constructs in Salinas. For a more detailed description of how to use Salinas , we refer the reader to Salinas, User's Notes. Many of the constructs in Salinas are pulled directly from published material. Where possible, these materials are referenced herein. However, certain functions in Salinas are specific to our implementation. We try to be far more complete in those areas. The theory manual was developed from several sources including general notes, a programer-notes manual, the user's notes and of course the material in the open literature.

Salinas provides a massively parallel implementation of structural dynamics finite element analysis. This capability is required for high fidelity, validated models used in modal, vibration, static and shock analysis of weapons systems. General capabilities for modal, statics and transient dynamics are provided. Salinas is similar to commercial codes like Nastran or Abaqus. It has some nonlinear capability, but excels in linear computation. It is different than the above commercial codes in that it is designed to operate efficiently in a massively parallel environment. Even for an experienced analyst, running a new finite element package can be a challenge. This little primer is intended to make part of this task easier by presenting the basic steps in a simple way. The analyst is referred to the theory manual for details of the mathematics behind the work. The User's Notes should be used for more complex inputs, and will have more details about the process (as well as many more examples). More information can be found on our web pages, 3 or 4. Finite element analysis can be deceptive. Any software can give the wrong answers if used improperly, and occasionally even when used properly. Certainly a solid background in structural mechanics is necessary to build an adequate finite element model and interpret the results. This primer should provide a quick start in answering some of the more common questions that come up in using Salinas.

This work presents an experimental evaluation of patch repair of solid laminated composites. The study was focused on destructive and nondestructive tests of full-scale repaired panels under static tension loading conditions. The testing program consisted of ten panels: three pristine, three damaged, three repaired and one repaired with mismatched fiber orientation patch. The evaluated panels were (300 mm x 675 mm) in size and consisted of 6-ply ((-60 /60/0){sub s}) quasi-isotropic laminates. The destructive tests were performed by North Carolina A&T State University and the nondestructive tests were performed by Iowa State University using Pulse-echo C-scan, Air coupled TTU and Auto-Tap. Sandia National Laboratories validated the NDT tests by implementing NDE field methods. Based on the evaluation performed in this study, it appears that the patch repair is an effective means in retrofitting damaged solid composite laminates.

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The peridynamic theory of continuum mechanics allows damage, fracture, and long-range forces to be treated as natural components of the deformation of a material. In this paper, the peridynamic approach is applied to small thickness two- and one-dimensional structures. For membranes, a constitutive model is described appropriate for rubbery sheets that can form cracks. This model is used to perform numerical simulations of the stretching and dynamic tearing of membranes. A similar approach is applied to one-dimensional string like structures that undergrow stretching, bending, and failure. Long-range forces similar to van der Waals interactions at the nanoscale influence the equilibrium configurations of these structures, how they deform, and possibly self-assembly.

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A laser hazard analysis to determine the Extended Ocular Hazard Distances associated with a possible intrabeam aided viewing of the Sandia Remote Sensing System (SRSS) airborne AURA laser (Big Sky Laser Technology) was performed based on the 2000 version of the American National Standard Institute's (ANSI) Standard Z136.1, for the Safe Use of Lasers and the 2000 version of the ANSI Standard Z136.6, for the Safe Use of Lasers Outdoors. The AURA lidar system is installed in the instrument pod of a Proteus airframe and is used to perform laser interaction experiments and tests at various national test sites. The targets are located at various distances (ranges) from the airborne platform. Nominal Ocular Hazard Distance (NOHD) and maximum ''eye-safe'' dwell times for various operational altitudes associated with unaided intrabeam exposure of ground personnel were determined and presented in a previous SAND report. Although the target areas are controlled and the use of viewing aids are prohibited there is the possibility of the unauthorized use of viewing aids such as binoculars. This aided viewing hazard analysis is supplemental to the previous SAND report for the laser hazard analysis of the airborne AURA.

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We present all-atom molecular dynamics simulations of biologically realistic transmembrane potential gradients across a DMPC bilayer. These simulations are the first to model this gradient in all-atom detail, with the field generated solely by explicit ion dynamics. Unlike traditional bilayer simulations that have one bilayer per unit cell, we simulate a 170 mV potential gradient by using a unit cell consisting of three salt-water baths separated by two bilayers, with full three-dimensional periodicity. The study shows that current computational resources are powerful enough to generate a truly electrified interface, as we show the predicted effect of the field on the overall charge distribution. Additionally, starting from Poisson's equation, we show a new derivation of the double integral equation for calculating the potential profile in systems with this type of periodicity.

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