Publications

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Despite decades of international consensus that deep geological disposal is the best option for permanent management of long-lived high-level radioactive wastes, no repositories for used nuclear fuel or high-level waste are in operation. Detailed long-term safety assessments have been completed worldwide for a wide range of repository designs and disposal concepts, however, and valuable insights from these assessments are available to inform future decisions about managing radioactive wastes. Qualitative comparisons among the existing safety assessments for disposal concepts in clay, granite, salt, and unsaturated volcanic tuff show how different geologic settings can be matched with appropriate engineered barrier systems to provide a high degree of confidence in the long-term safety of geologic disposal. Review of individual assessments provides insights regarding the release pathways and radionuclides that are most likely to contribute to estimated doses to humans in the far future for different disposal concepts, and can help focus research and development programs to improve management and disposal technologies. Lessons learned from existing safety assessments may be particularly relevant for informing decisions during the process of selecting potential repository sites.

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This document provides detailed test results of ballistic impact experiments performed on several types of high performance concrete. These tests were performed at the Sandia National Laboratories Shock Thermodynamic Applied Research Facility using a 50 caliber powder gun to study penetration resistance of concrete samples. This document provides test results for ballistic impact experiments performed on two types of concrete samples, (1) Ductal{reg_sign} concrete is a fiber reinforced high performance concrete patented by Lafarge Group and (2) ultra-high performance concrete (UHPC) produced in-house by DoD. These tests were performed as part of a research demonstration project overseen by USACE and ERDC, at the Sandia National Laboratories Shock Thermodynamic Applied Research (STAR) facility. Ballistic penetration tests were performed on a single stage research powder gun of 50 caliber bore using a full metal jacket M33 ball projectile with a nominal velocity of 914 m/s (3000 ft/s). Testing was observed by Beverly DiPaolo from ERDC-GSL. In all, 31 tests were performed to achieve the test objectives which were: (1) recovery of concrete test specimens for post mortem analysis and characterization at outside labs, (2) measurement of projectile impact velocity and post-penetration residual velocity from electronic and radiographic techniques and, (3) high-speed photography of the projectile prior to impact, impact and exit of the rear surface of the concrete construct, and (4) summarize the results.

Climate change is a long-term process that will trigger a range of multi-dimensional demographic, economic, geopolitical, and national security issues with many unknowns and significant uncertainties. At first glance, climate-change-related national security dimensions seem far removed from today's major national security threats. Yet climate change has already set in motion forces that will require U.S. attention and preparedness. The extent and uncertainty associated with these situations necessitate a move away from conventional security practices, toward a small but flexible portfolio of assets to maintain U.S. interests. Thoughtful action is required now if we are to acquire the capabilities, tools, systems, and institutions needed to meet U.S. national security requirements as they evolve with the emerging stresses and shifts of climate change.

The growth and decomposition of thin layers of Mg and magnesium hydride on Ru(0001) using an in situ technique that provides real-space, real-time observations of the formation of hydride islands, was reported. The experiments have been performed using low energy electron microscopy (LEEM). Using LEEM, the growth of films was followed up to 10 atomic layers (AL) for temperatures between 300 and 430 K. With increased exposure time, there is little further nucleation. The LEED patterns of the 4 AL Mg film shows two sets of 6-fold diffraction spots, one set from the film and the other from the substrate. After being exposed to hydrogen the films were heated in UHV and the surface was simultaneously imaged by LEEM and gas generation monitored by temperature desorption (TD). In the LEEM images, no changes were observed up to temperatures around 450 K. From this temperature desorption of the Mg layers started. An increase in the decomposition temperature is observed with thicker original Mg films.

A novel multi-scale approach for extending the one-dimensional turbulence (ODT) model of [A.R. Kerstein. One-dimensional turbulence: model formulation and application to homogeneous turbulence, shear flows, and buoyant stratified flows, J. Fluid Mech. 392 (1999) 277] to treat turbulent flow in three-dimensional (3D) domains is described. In this model, here called ODTLES, 3D aspects of the flow are captured by embedding three, mutually orthogonal, one-dimensional ODT domain arrays within a coarser 3D mesh. The ODTLES model is obtained by developing a consistent approach for dynamically coupling the different ODT line sets to each other and to the large scale processes that are resolved on the 3D mesh. The model is implemented computationally and its performance is tested by performing simulations of decaying isotropic turbulence at two different Reynolds numbers and comparing to the experimental data of [H. Kang, S. Chester, C. Meneveau. Decaying turbulence in an active-grid-generated flow and comparisons with large-eddy simulations, J. Fluid Mech. 480 (2003) 129; G. Comte-Bellot, S. Corrsin, Simple Eulerian correlation of full-and narrow band velocity signals in grid-generated 'isotropic' turbulence, J. Fluid Mech. 48 (1971) 273]. © 2008 Elsevier B.V.

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Rates of reactions can be expressed as dn/dt = kcf(n) where n is moles of reaction, k is a rate constant, c is a proportionality constant, and f(n) is a function of the properties of the sample. When the instrument time constant, ?, and k are sufficiently comparable that measured rates are significantly affected by instrument response, correction for instrument response must be done to obtain accurate reaction kinetics. Correction for instrument response has previously been done by truncating early data or by use of the Tian equation. Both methods can lead to significant errors. We describe a method for simultaneous determination of ?, k, and c by fitting equations describing the combined instrument response and rate law to rates observed as a function of time. The method was tested with data on the heat rate from acid-catalyzed hydrolysis of sucrose.

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Near-field scanning microwave microscopy is employed for quantitative imaging at 4 GHz of the local impedance for monolayer and few-layer graphene. The microwave response of graphene is found to be thickness dependent and determined by the local sheet resistance of the graphene flake. Calibration of the measurement system and knowledge of the probe geometry allows evaluation of the AC impedance for monolayer and few-layer graphene, which is found to be predominantly active. The use of localized evanescent electromagnetic field in our experiment provides a promising tool for investigations of plasma waves in graphene with wave numbers determined by the spatial spectrum of the near-field. By using near-field microwave microscopy one can perform simultaneous imaging of location, geometry, thickness, and distribution of electrical properties of graphene without a need for device fabrication.

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Portable remote sensing devices are increasingly needed to cost effectively characterize the meteorology at a potential wind energy site as the size of modern wind turbines increase. A short term project co-locating a Sound Detection and Ranging System (SODAR) with a 200 meter instrumented meteorological tower at the Texas Tech Wind Technology Field Site was performed to collect and summarize wind information through an atmospheric layer typical of utility scale rotor plane depths. Data collected identified large speed shears and directional shears that may lead to unbalanced loads on the rotors. This report identifies suggestions for incorporation of additional data in wind resource assessments and a few thoughts on the potential for using a SODAR or SODAR data to quantify or investigate other parameters that may be significant to the wind industry.

This assessment takes the result of the FY08 performance target baseline of mercury at Sandia National Laboratories/New Mexico, and records the steps taken in FY09 to collect additional data, encourage the voluntary reduction of mercury, and measure success. Elemental (metallic) mercury and all of its compounds are toxic, and exposure to excessive levels can permanently damage or fatally injure the brain and kidneys. Elemental mercury can also be absorbed through the skin and cause allergic reactions. Ingestion of inorganic mercury compounds can cause severe renal and gastrointestinal damage. Organic compounds of mercury such as methyl mercury, created when elemental mercury enters the environment, are considered the most toxic forms of the element. Exposures to very small amounts of these compounds can result in devastating neurological damage and death.1 SNL/NM is required to report annually on the site wide inventory of mercury for the Environmental Protection Agency's (EPA) Toxics Release Inventory (TRI) Program, as the site's inventory is excess of the ten pound reportable threshold quantity. In the fiscal year 2008 (FY08) Pollution Prevention Program Plan, Section 5.3 Reduction of Environmental Releases, a performance target stated was to establish a baseline of mercury, its principle uses, and annual quantity or inventory. This was accomplished on July 29, 2008 by recording the current status of mercury in the Chemical Information System (CIS).

Knight & Carver was contracted by Sandia National Laboratories to develop a Sweep Twist Adaptive Rotor (STAR) blade that reduced operating loads, thereby allowing a larger, more productive rotor. The blade design used outer blade sweep to create twist coupling without angled fiber. Knight & Carver successfully designed, fabricated, tested and evaluated STAR prototype blades. Through laboratory and field tests, Knight & Carver showed the STAR blade met the engineering design criteria and economic goals for the program. A STAR prototype was successfully tested in Tehachapi during 2008 and a large data set was collected to support engineering and commercial development of the technology. This report documents the methodology used to develop the STAR blade design and reviews the approach used for laboratory and field testing. The effort demonstrated that STAR technology can provide significantly greater energy capture without higher operating loads on the turbine.

A Sewer System Management Plan (SSMP) is required by the State Water Resources Control Board (SWRCB) Order No. 2006-0003-DWQ Statewide General Waste Discharge Requirements (WDR) for Sanitary Sewer Systems (General Permit). DOE, National Nuclear Security Administration (NNSA), Sandia Site Office has filed a Notice of Intent to be covered under this General Permit. The General Permit requires a proactive approach to reduce the number and frequency of sanitary sewer overflows (SSOs) within the State. SSMPs must include provisions to provide proper and efficient management, operation, and maintenance of sanitary sewer systems and must contain a spill response plan. Elements of this Plan are under development in accordance with the SWRCB's schedule.

The intent of this study is to provide an analysis of the scattering from a crevasse in Antarctic ice, utilizing a physics-based model for the scattering process. Of primary interest is a crevasse covered with a snow bridge, which makes the crevasse undetectable in visible-light images. It is demonstrated that a crevasse covered with a snow bridge can be visible in synthetic-aperture-radar (SAR) images. The model of the crevasse and snow bridge incorporates a complex dielectric permittivity model for dry snow and ice that takes into account the density profile of the glacier. The surface structure is based on a fractal model that can produce sastrugi-like features found on the surface of Antarctic glaciers. Simulated phase histories, computed with the Shooting and Bouncing Ray (SBR) method, are processed into SAR images. The viability of the SBR method for predicting scattering from a crevasse covered with a snow bridge is demonstrated. Some suggestions for improving the model are given.

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Sandia National Laboratories is currently developing new processing and data communication architectures for use in future satellite payloads. These architectures will leverage the flexibility and performance of state-of-the-art static-random-access-memory-based Field Programmable Gate Arrays (FPGAs). One such FPGA is the radiation-hardened version of the Virtex-5 being developed by Xilinx. However, not all features of this FPGA are being radiation-hardened by design and could still be susceptible to on-orbit upsets. One such feature is the embedded hard-core PPC440 processor. Since this processor is implemented in the FPGA as a hard-core, traditional mitigation approaches such as Triple Modular Redundancy (TMR) are not available to improve the processor's on-orbit reliability. The goal of this work is to investigate techniques that can help mitigate the embedded hard-core PPC440 processor within the Virtex-5 FPGA other than TMR. Implementing various mitigation schemes reliably within the PPC440 offers a powerful reconfigurable computing resource to these node-based processing architectures. This document summarizes the work done on the cache mitigation scheme for the embedded hard-core PPC440 processor within the Virtex-5 FPGAs, and describes in detail the design of the cache mitigation scheme and the testing conducted at the radiation effects facility on the Texas A&M campus.

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An increasing number of corporate security policies make it desirable to push security closer to the desktop. It is not practical or feasible to place security and monitoring software on all computing devices (e.g. printers, personal digital assistants, copy machines, legacy hardware). We have begun to prototype a hardware and software architecture that will enforce security policies by pushing security functions closer to the end user, whether in the office or home, without interfering with users' desktop environments. We are developing a specialized programmable Ethernet network switch to achieve this. Embodied in this device is the ability to detect and mitigate network attacks that would otherwise disable or compromise the end user's computing nodes. We call this device a 'Secure Programmable Switch' (SPS). The SPS is designed with the ability to be securely reprogrammed in real time to counter rapidly evolving threats such as fast moving worms, etc. This ability to remotely update the functionality of the SPS protection device is cryptographically protected from subversion. With this concept, the user cannot turn off or fail to update virus scanning and personal firewall filtering in the SPS device as he/she could if implemented on the end host. The SPS concept also provides protection to simple/dumb devices such as printers, scanners, legacy hardware, etc. This report also describes the development of a cryptographically protected processor and its internal architecture in which the SPS device is implemented. This processor executes code correctly even if an adversary holds the processor. The processor guarantees both the integrity and the confidentiality of the code: the adversary cannot determine the sequence of instructions, nor can the adversary change the instruction sequence in a goal-oriented way.

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We recently performed an evaluation of the implications of a reduced stockpile of nuclear weapons for surveillance to support estimates of reliability. We found that one technique developed at Sandia National Laboratories (SNL) under-estimates the required sample size for systems-level testing. For a large population the discrepancy is not important, but for a small population it is important. We found that another technique used by SNL provides the correct required sample size. For systems-level testing of nuclear weapons, samples are selected without replacement, and the hypergeometric probability distribution applies. Both of the SNL techniques focus on samples without defects from sampling without replacement. We generalized the second SNL technique to cases with defects in the sample. We created a computer program in Mathematica to automate the calculation of confidence for reliability. We also evaluated sampling with replacement where the binomial probability distribution applies.

This paper describes a new hybrid modeling and simulation architecture developed at Sandia for understanding and developing protections against and mitigations for cyber threats upon control systems. It first outlines the challenges to PCS security that can be addressed using these technologies. The paper then describes Virtual Control System Environments (VCSE) that use this approach and briefly discusses security research that Sandia has performed using VCSE. It closes with recommendations to the control systems security community for applying this valuable technology.

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Uncertainty may be introduced into RADTRAN analyses by distributing input parameters. The MELCOR Uncertainty Engine (Gauntt and Erickson, 2004) has been adapted for use in RADTRAN to determine the parameter shape and minimum and maximum of the distribution, to sample on the distribution, and to create an appropriate RADTRAN batch file. Coupling input parameters is not possible in this initial application. It is recommended that the analyst be very familiar with RADTRAN and able to edit or create a RADTRAN input file using a text editor before implementing the RADTRAN Uncertainty Analysis Module. Installation of the MELCOR Uncertainty Engine is required for incorporation of uncertainty into RADTRAN. Gauntt and Erickson (2004) provides installation instructions as well as a description and user guide for the uncertainty engine.

Specimens of poled and unpoled PZST ceramic were tested under hydrostatic loading conditions at temperatures of -55, 25, and 75 C. The objective of this experimental study was to obtain the electro-mechanical properties of the ceramic and the criteria of FE (Ferroelectric) to AFE (Antiferroelectric) phase transformations of the PZST ceramic to aid grain-scale modeling efforts in developing and testing realistic response models for use in simulation codes. As seen in previous studies, the poled ceramic from PZST undergoes anisotropic deformation during the transition from a FE to an AFE phase at -55 C. Warmer temperature tests exhibit anisotropic deformation in both the FE and AFE phase. The phase transformation is permanent at -55 C for all ceramics tests, whereas the transformation can be completely reversed at 25 and 75 C. The change in the phase transformation pressures at different temperatures were practically identical for both unpoled and poled PZST specimens. Bulk modulus for both poled and unpoled material was lowest in the FE phase, intermediate in the transition phase, and highest in the AFE phase. Additionally, bulk modulus varies with temperature in that PZST is stiffer as temperature decreases. Results from one poled-biased test for PZST and four poled-biased tests from PNZT 95/5-2Nb are presented. A bias of 1kV did not show noticeable differences in phase transformation pressure for the PZST material. However, with PNZT 95/5-2Nb phase transformation pressure increased with increasing voltage bias up to 4.5kV.

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This report is a revision of SAND2009-0852. SAND2009-0852 was revised because it was discovered that a gage used in the original testing was mis-calibrated. Following the recalibration, all affected raw data were recalculated and re-presented. Most revised data is similar to, but slightly different than, the original data. Following the data re-analysis, none of the inferences or conclusions about the data or site relative to the SAND2009-0852 data have been changed. A laboratory testing program was developed to examine the mechanical behavior of salt from the Richton salt dome. The resulting information is intended for use in design and evaluation of a proposed Strategic Petroleum Reserve storage facility in that dome. Core obtained from the drill hole MRIG-9 was obtained from the Texas Bureau of Economic Geology. Mechanical properties testing included: (1) acoustic velocity wave measurements; (2) indirect tensile strength tests; (3) unconfined compressive strength tests; (4) ambient temperature quasi-static triaxial compression tests to evaluate dilational stress states at confining pressures of 725, 1450, 2175, and 2900 psi; and (5) confined triaxial creep experiments to evaluate the time-dependent behavior of the salt at axial stress differences of 4000 psi, 3500 psi, 3000 psi, 2175 psi and 2000 psi at 55 C and 4000 psi at 35 C, all at a constant confining pressure of 4000 psi. All comments, inferences, discussions of the Richton characterization and analysis are caveated by the small number of tests. Additional core and testing from a deeper well located at the proposed site is planned. The Richton rock salt is generally inhomogeneous as expressed by the density and velocity measurements with depth. In fact, we treated the salt as two populations, one clean and relatively pure (> 98% halite), the other salt with abundant (at times) anhydrite. The density has been related to the insoluble content. The limited mechanical testing completed has allowed us to conclude that the dilatational criteria are distinct for the halite-rich and other salts, and that the dilation criteria are pressure dependent. The indirect tensile strengths and unconfined compressive strengths determined are consistently lower than other coastal domal salts. The steady-state-only creep model being developed suggests that Richton salt is intermediate in creep resistance when compared to other domal and bedded salts. The results of the study provide only limited information for structural modeling needed to evaluate the integrity and safety of the proposed cavern field. This study should be augmented with more extensive testing. This report documents a series of test methods, philosophies, and empirical relationships, etc., that are used to define and extend our understanding of the mechanical behavior of the Richton salt. This understanding could be used in conjunction with planned further studies or on its own for initial assessments.

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Los Alamos and Sandia National Laboratories are partners in an effort to survey the super-cooled liquid water in clouds over the state of New Mexico in a project sponsored by the New Mexico Small Business Assistance Program. This report summarizes the scientific work performed at Sandia National Laboratories during the 2009. In this second year of the project a practical methodology for estimating cloud super-cooled liquid water was created. This was accomplished through the analysis of certain MODIS sensor satellite derived cloud products and vetted parameterizations techniques. A software code was developed to analyze multiple cases automatically. The eighty-one storm events identified in the previous year effort from 2006-2007 were again the focus. Six derived MODIS products were obtained first through careful MODIS image evaluation. Both cloud and clear-sky properties from this dataset were determined over New Mexico. Sensitivity studies were performed that identified the parameters which most influenced the estimation of cloud super-cooled liquid water. Limited validation was undertaken to ensure the soundness of the cloud super-cooled estimates. Finally, a path forward was formulized to insure the successful completion of the initial scientific goals which include analyzing different of annual datasets, validation of the developed algorithm, and the creation of a user-friendly and interactive tool for estimating cloud super-cooled liquid water.

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This guide describes a high-level, technology-neutral framework for assessing potential benefits from and economic market potential for energy storage used for electric-utility-related applications. The overarching theme addressed is the concept of combining applications/benefits into attractive value propositions that include use of energy storage, possibly including distributed and/or modular systems. Other topics addressed include: high-level estimates of application-specific lifecycle benefit (10 years) in $/kW and maximum market potential (10 years) in MW. Combined, these criteria indicate the economic potential (in $Millions) for a given energy storage application/benefit. The benefits and value propositions characterized provide an important indication of storage system cost targets for system and subsystem developers, vendors, and prospective users. Maximum market potential estimates provide developers, vendors, and energy policymakers with an indication of the upper bound of the potential demand for storage. The combination of the value of an individual benefit (in $/kW) and the corresponding maximum market potential estimate (in MW) indicates the possible impact that storage could have on the U.S. economy. The intended audience for this document includes persons or organizations needing a framework for making first-cut or high-level estimates of benefits for a specific storage project and/or those seeking a high-level estimate of viable price points and/or maximum market potential for their products. Thus, the intended audience includes: electric utility planners, electricity end users, non-utility electric energy and electric services providers, electric utility regulators and policymakers, intermittent renewables advocates and developers, Smart Grid advocates and developers, storage technology and project developers, and energy storage advocates.

Radial wire arrays provide an alternative x-ray source for Z-pinch driven Inertial Confinement Fusion. These arrays, where wires are positioned radially outwards from a central cathode to a concentric anode, have the potential to drive a more compact ICF hohlraum. A number of experiments were performed on the 7MA Saturn Generator. These experiments studied a number of potential risks in scaling radial wire arrays up from the 1MA level, where they have been shown to provide similar x-ray outputs to larger diameter cylindrical arrays, to the higher current levels required for ICF. Data indicates that at 7MA radial arrays can obtain higher power densities than cylindrical wire arrays, so may be of use for x-ray driven ICF on future facilities. Even at the 7MA level, data using Saturn's short pulse mode indicates that a radial array should be able to drive a compact hohlraum to temperatures {approx}92eV, which may be of interest for opacity experiments. These arrays are also shown to have applications to jet production for laboratory astrophysics. MHD simulations require additional physics to match the observed behavior.

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This report describes the activities and results of a Sandia LDRD project whose objective was to develop and demonstrate foundational aspects of a next-generation nuclear reactor safety code that leverages advanced computational technology. The project scope was directed towards the systems-level modeling and simulation of an advanced, sodium cooled fast reactor, but the approach developed has a more general applicability. The major accomplishments of the LDRD are centered around the following two activities. (1) The development and testing of LIME, a Lightweight Integrating Multi-physics Environment for coupling codes that is designed to enable both 'legacy' and 'new' physics codes to be combined and strongly coupled using advanced nonlinear solution methods. (2) The development and initial demonstration of BRISC, a prototype next-generation nuclear reactor integrated safety code. BRISC leverages LIME to tightly couple the physics models in several different codes (written in a variety of languages) into one integrated package for simulating accident scenarios in a liquid sodium cooled 'burner' nuclear reactor. Other activities and accomplishments of the LDRD include (a) further development, application and demonstration of the 'non-linear elimination' strategy to enable physics codes that do not provide residuals to be incorporated into LIME, (b) significant extensions of the RIO CFD code capabilities, (c) complex 3D solid modeling and meshing of major fast reactor components and regions, and (d) an approach for multi-physics coupling across non-conformal mesh interfaces.

Between November 30 and December 11, 2009 an evaluation was performed of the probability of containment failure and the time for cleanup of contamination of the Z machine given failure, for plutonium (Pu) experiments on the Z machine at Sandia National Laboratories (SNL). Due to the unique nature of the problem, there is little quantitative information available for the likelihood of failure of containment components or for the time to cleanup. Information for the evaluation was obtained from Subject Matter Experts (SMEs) at the Z machine facility. The SMEs provided the State of Knowledge (SOK) for the evaluation. There is significant epistemic- or state of knowledge- uncertainty associated with the events that comprise both failure of containment and cleanup. To capture epistemic uncertainty and to allow the SMEs to reason at the fidelity of the SOK, we used the belief/plausibility measure of uncertainty for this evaluation. We quantified two variables: the probability that the Pu containment system fails given a shot on the Z machine, and the time to cleanup Pu contamination in the Z machine given failure of containment. We identified dominant contributors for both the time to cleanup and the probability of containment failure. These results will be used by SNL management to decide the course of action for conducting the Pu experiments on the Z machine.

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During the past several years, there has been a growing recognition of the threats posed by the use of shallow tunnels against both international border security and the integrity of critical facilities. This has led to the development and testing of a variety of geophysical and surveillance techniques for the detection of these clandestine tunnels. The challenges of detection of these tunnels arising from the complexity of the near surface environment, the subtlety of the tunnel signatures themselves, and the frequent siting of these tunnels in urban environments with a high level of cultural noise, have time and again shown that any single technique is not robust enough to solve the tunnel detection problem in all cases. The question then arises as to how to best combine the multiple techniques currently available to create an integrated system that results in the best chance of detecting these tunnels in a variety of clutter environments and geologies. This study utilizes Taguchi analysis with simulated sensor detection performance to address this question. The analysis results show that ambient noise has the most effect on detection performance over the effects of tunnel characteristics and geological factors.

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This report summarizes a brief and unsuccessful attempt to grow indium nitride via the electrochemical solution growth method and a modification thereof. Described in this report is a brief effort using a $50,000 LDRD award to explore the possibilities of applying the Electrochemical Solution Growth (ESG) technique to the growth of indium nitride (InN). The ability to grow bulk InN would be exciting from a scientific perspective, and a commercial incentive lies in the potential of extending the ESG technique to grow homogeneous, bulk alloys of In{sub x}Ga{sub 1-x}N for light emitting diodes (LEDs) operating in the green region of the spectrum. Indium nitride is the most difficult of the III-nitrides to grow due to its very high equilibrium vapor pressure of nitrogen1. It is several orders of magnitude higher than for gallium nitride or aluminum nitride. InN has a bandgap energy of 0.7eV, and achieving its growth in bulk for large area, high quality substrates would permit the fabrication of LEDs operating in the infrared. By alloying with GaN and AlN, the bulk material used as substrates would enable high efficiency emission wavelengths that could be tailored all the way through the deep ultraviolet. In addition, InN has been shown to have very high electronic mobilities (2700 cm{sup 2}/V s), making it a promising material for transistors and even terahertz emitters. Several attempts at synthesizing InN have been made by several groups. It was shown that metallic indium does not interact with unactivated nitrogen even at very high temperatures. Thus sets up an incompatibility between the precursors in all growth methods: a tradeoff between thermally activating the nitrogen-containing precursor and the low decomposition temperature of solid InN. We have been working to develop a novel growth technique that circumvents the difficulties of other bulk growth techniques by precipitating the column III nitrides from a solvent, such as a molten chloride salt, that provides an excellent host environment for the gallium nitride and indium nitride precursors. In particular, we have found that molten halide salts can solubilize both gallium (Ga{sup 3+}) and nitride (N{sup 3-}) ions without reacting with them to the extent that they are no longer available for reaction with each other. Literature reports indicate measured nitride ion concentrations in LiCl at 650 C as high as 10 mol% - a sufficient concentration to yield growth rates on the order of 0.1 to {approx}1 mm/hr under diffusion-limited growth conditions. Also, molten salts are compatible with the 400-1200 C temperatures likely to be necessary for growth of high-quality single-crystal III-nitrides. Since they can be worked with at (or close to) atmospheric pressure, scalability is not a problem and manufacturability issues are thus minimized, including capital equipment costs. Although the III-nitrides cannot be float-zone refined to remove impurities due to their high melting temperatures and vapor pressures, the salts can be, thus reducing sources of impurities before growth begins. Finally, the molten salts offer a number of pathways to improve the solubility and control the growth of the III-nitrides by functioning as an electrolyte in electrochemical processes. We have already demonstrated growth of wurtzite GaN particles ranging from 0.2 to 0.9 mm in two hours in our laboratory using these techniques. It was the goal of this work to extend this ESG approach to the growth of indium nitride. The hope was that the abundance of the activated form of nitrogen, namely the triply-charged nitride ion (N{sup -3}) would enable the facile growth of InN in solution at low temperatures.

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2-Chloroethyl phenyl sulfide (CEPS), a surrogate compound of the chemical warfare agent sulfur mustard, was examined using thermal desorption coupled gas chromatography-mass spectrometry (TD/GC-MS) and multivariate analysis. This work describes a novel method of producing multiway data using a stepped thermal desorption. Various multivariate analysis schemes were employed to analyze the data. These methods may be able to discern different sources of CEPS. In addition, CEPS was applied to cotton, nylon, polyester, and silk swatches. These swatches were placed in controlled humidity chambers maintained at 23%, 56%, and 85% relative humidity. At regular intervals, samples were removed from each test swatch, and the samples analyzed using TD/GC-MS. The results were compared across fabric substrate and humidity.

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The annual program report provides detailed information about all aspects of the Sandia National Laboratories, California (SNL/CA) Waste Management Program. It functions as supporting documentation to the SNL/CA Environmental Management System Program Manual. This annual program report describes the activities undertaken during the past year, and activities planned in future years to implement the Waste Management (WM) Program, one of six programs that supports environmental management at SNL/CA.

The Arquin Corporation has developed a new method of constructing CMU (concrete masonry unit) walls. This new method uses polymer spacers connected to steel wires that serve as reinforcing as well as a means of accurately placing the spacers so that the concrete block can be dry stacked. The hollows of the concrete block are then filled with grout. As part of a New Mexico Small Business Assistance Program (NMSBA), Sandia National Laboratories conducted a series of tests that dynamically loaded wall segments to compare the performance of walls constructed using the Arquin method to a more traditional method of constructing CMU walls. A total of four walls were built, two with traditional methods and two with the Arquin method. Two of the walls, one traditional and one Arquin, had every third cell filled with grout. The remaining two walls, one traditional and one Arquin, had every cell filled with grout. The walls were dynamically loaded with explosive forces. No significant difference was noted between the performance of the walls constructed by the Arquin method when compared to the walls constructed by the traditional method.

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In this report, we examine the propagation of tensile waves of finite deformation in rubbers through experiments and analysis. Attention is focused on the propagation of one-dimensional dispersive and shock waves in strips of latex and nitrile rubber. Tensile wave propagation experiments were conducted at high strain-rates by holding one end fixed and displacing the other end at a constant velocity. A high-speed video camera was used to monitor the motion and to determine the evolution of strain and particle velocity in the rubber strips. Analysis of the response through the theory of finite waves and quantitative matching between the experimental observations and analytical predictions was used to determine an appropriate instantaneous elastic response for the rubbers. This analysis also yields the tensile shock adiabat for rubber. Dispersive waves as well as shock waves are also observed in free-retraction experiments; these are used to quantify hysteretic effects in rubber.

The formation of silica scale is a problem for thermoelectric power generating facilities, and this study investigated the potential for removal of silica by means of chemical coagulation from source water before it is subjected to mineral concentration in cooling towers. In Phase I, a screening of many typical as well as novel coagulants was carried out using concentrated cooling tower water, with and without flocculation aids, at concentrations typical for water purification with limited results. In Phase II, it was decided that treatment of source or make up water was more appropriate, and that higher dosing with coagulants delivered promising results. In fact, the less exotic coagulants proved to be more efficacious for reasons not yet fully determined. Some analysis was made of the molecular nature of the precipitated floc, which may aid in process improvements. In Phase III, more detailed study of process conditions for aluminum chloride coagulation was undertaken. Lime-soda water softening and the precipitation of magnesium hydroxide were shown to be too limited in terms of effectiveness, speed, and energy consumption to be considered further for the present application. In Phase IV, sodium aluminate emerged as an effective coagulant for silica, and the most attractive of those tested to date because of its availability, ease of use, and low requirement for additional chemicals. Some process optimization was performed for coagulant concentration and operational pH. It is concluded that silica coagulation with simple aluminum-based agents is effective, simple, and compatible with other industrial processes.

The Technical Area V (TA-V) Seismic Assessment Report was commissioned as part of Sandia National Laboratories (SNL) Self Assessment Requirement per DOE O 414.1, Quality Assurance, for seismic impact on existing facilities at Technical Area-V (TA-V). SNL TA-V facilities are located on an existing Uniform Building Code (UBC) Seismic Zone IIB Site within the physical boundary of the Kirtland Air Force Base (KAFB). The document delineates a summary of the existing facilities with their safety-significant structure, system and components, identifies DOE Guidance, conceptual framework, past assessments and the present Geological and Seismic conditions. Building upon the past information and the evolution of the new seismic design criteria, the document discusses the potential impact of the new standards and provides recommendations based upon the current International Building Code (IBC) per DOE O 420.1B, Facility Safety and DOE G 420.1-2, Guide for the Mitigation of Natural Phenomena Hazards for DOE Nuclear Facilities and Non-Nuclear Facilities.

We describe a method that enables Monte Carlo calculations to automatically achieve a user-prescribed error of representation for numerical results. Our approach is to iteratively adapt Monte Carlo functional-expansion tallies (FETs). The adaptivity is based on assessing the cellwise 2-norm of error due to both functional-expansion truncation and statistical uncertainty. These error metrics have been detailed by others for one-dimensional distributions. We extend their previous work to threedimensional distributions and demonstrate the use of these error metrics for adaptivity. The method examines Monte Carlo FET results, estimates truncation and uncertainty error, and suggests a minimumrequired expansion order and run time to achieve the desired level of error. Iteration is required for results to converge to the desired error. Our implementation of adaptive FETs is observed to converge to reasonable levels of desired error for the representation of four distributions. In practice, some distributions and desired error levels may require prohibitively large expansion orders and/or Monte Carlo run times.

The formation of mineral scale deposits on membranes is a pervasive and expensive problem for the water treatment industry. A series of experiments run on a laboratory-scale reverse osmosis membrane system examined the fouling of membranes when the feed water was spiked with organic and inorganic foulants. Alginic acid was used as the organic foulant and silica was used as the inorganic foulant. Studies involving interactions of these two foulants have not previously been reported in literature. Experiments were run with each foulant individually to characterize fouling at different velocities and pressures. Experiments were then run using both foulants together to characterize the synergistic effects on membrane fouling. One set of experiments with both foulants demonstrated that alginic acid inhibits silica fouling on reverse osmosis membranes. Further experiments indicated that alginic acid added after silica fouling had already occurred was able to remove silica scale from the membrane and restore permeate flux. © 2009 Elsevier B.V.

We describe a method that enables Monte Carlo calculations to automatically achieve a user-prescribed error of representation for numerical results. Our approach is to iteratively adapt Monte Carlo functional-expansion tallies (FETs). The adaptivity is based on assessing the cellwise 2-norm of error due to both functional-expansion truncation and statistical uncertainty. These error metrics have been detailed by others for one-dimensional distributions. We extend their previous work to threedimensional distributions and demonstrate the use of these error metrics for adaptivity. The method examines Monte Carlo FET results, estimates truncation and uncertainty error, and suggests a minimumrequired expansion order and run time to achieve the desired level of error. Iteration is required for results to converge to the desired error. Our implementation of adaptive FETs is observed to converge to reasonable levels of desired error for the representation of four distributions. In practice, some distributions and desired error levels may require prohibitively large expansion orders and/or Monte Carlo run times.

We examine a new method of producing reduced order models for LTI systems which attempts to minimize a bound on the peak error between t he original and reduced order models subject to a bound on the peak value of the input. The method, which can be implemented by solving a set of linear programming problems that are parameterized v ia a single scalar quantity, is able to minimize an error bound subject to a number of moment matc hing constraints. Moreover, because all optimization is performed in the time domain, the method can also be used to perform model reduction for infinite dimensional systems, rather than being restricted to finite order state space descriptions. We begin by contrasting the method we present her e with two classes of standard model reduction algorithms, namely, moment matching algorithms and singular value-based methods. After motivating the class of reduction tools we propose, we describe the algorithm (which minimizes the Ll norm of the difference between the original and reduced order impulse responses) and formulate the corresponding linear programming problem that is solved during each iteration of the algorithm. We then prove that, for a certain class of LTI systems, the metho d we propose can be used to produce reduced order models of arbitrary accuracy even when the original system is infinite dimensional. We then show how to incorporate moment matching constraints into the basic error bound minimization algorithm, and present three examples which utilize the techni ques described herein. We conclude with some comments on extensions to multi-input, multi-output systems, as well as some general comments for future work. © 2010 Society for Industrial and Applied Mathematics.

The authors experimentally demonstrate a resonant hybridization between the magnetic dipole structural resonance in the permeability of a fishnet metamaterial and an electric dipole material resonance in the permittivity of the dielectric spacer layer. The hybrid resonances in the permeability and the negative index response exhibit an anticrossing behavior. A simple analytic model and numerical simulations using a rigorous coupled-wave analysis are in excellent qualitative agreement with the experiment. © 2010 American Vacuum Society.

We examine a new method of producing reduced order models for LTI systems which attempts to minimize a bound on the peak error between the original and reduced order models subject to a bound on the peak value of the input. The method, which can be implemented by solving a set of linear programming problems that are parameterized via a single scalar quantity, is able to minimize an error bound subject to a number of moment matching constraints.Moreover, because all optimization is performed in the time-domain, the method can also be used to perform model reduction for infinite dimensional systems, rather than being restricted to finite order state space descriptions. We begin by contrasting the method we present here to two classes of standard model reduction algorithms, namely moment matching algorithms and singularvalue- based methods. After motivating the class of reduction tools we propose, we describe the algorithm (which minimizes the L1 norm of the difference between the original and reduced order impulse responses) and formulate the corresponding linear programming problem that is solved during each iteration of the algorithm. We then show how to incorporate moment matching constraints into the basic error bound minimization algorithm, and present an example which utilizes the techniques described herein. We conclude with some general comments for future work, including a nonlinear programming formulation with potential implementation benefits. © 2010 AACC.

New Pb-free alloys that are variations of the Sn-Ag-Cu (SAC) ternary system, having reduced Ag content, are being developed to address the poor shock load survivability of current SAC305, SAC396, and SAC405 compositions. However, the thermal mechanical fatigue properties must be determined for the new alloys in order to develop constitutive models for predicting solder joint fatigue. A long-term study was initiated to investigate the time-independent (stress-strain) and time-dependent (creep) deformation properties of the alloy 98.5Sn-1.0Ag-0.5Cu (wt.% SAC105). The compression stress-strain properties, which are reported herein, were obtained for the solder in as-cast and aged conditions. The test temperatures were -25°C, 25°C, 75°C, 125°C, and 160°C and the strain rates were 4.2 × 10 -5 s -1 and 8.3 × 10 -4s -1. The SAC105 performance was compared with that of the 95.5Sn-3.9Ag-0.6Cu (SAC396) solder. Like the SAC396 solder, the SAC105 microstructure exhibited only small microstructural changes after deformation. The stress-strain curves showed work-hardening behavior that diminished with increased temperature to a degree that indicated dynamic recrystallization activity. The aging treatment had a small effect on the stress-strain curves, increasing the degree of work hardening. The yield stresses of SAC105 were significantly less than those of SAC396. The aging treatment caused a small drop in yield stress, as is observed with the SAC396 material. The static modulus values of SAC105 were lower than those of SAC396 and exhibited both temperature and aging treatment dependencies that differed from those of the SAC396 material. These trends clearly show that the stress-strain behavior of Sn-Ag-Cu solders is sensitive to the specific, individual composition. © 2009 U.S. Department of Energy.

Inspired by prior work in the design of switched feedback controllers for second order systems, we develop a switched state feedback control law for the stabilization of LTI systems of arbitrary dimension. The control law operates by switching between two static gain vectors in such a way that the state trajectory is driven onto a stable n - 1 dimensional hyperplane (where n represents the system dimension). We begin by briefly examining relevant geometric properties of the phase portraits in the case of two-dimensional systems and show how these geometric properties can be expressed as algebraic constraints on the switched vector fields that are applicable to LTI systems of arbitrary dimension. We then describe an explicit procedure for designing stabilizing controllers and illustrate the closed-loop transient performance via two examples. © 2010 AACC.

Wind tunnel experiments up to Mach 3 have provided fluctuating wall pressure spectra beneath a supersonic turbulent boundary layer to frequencies reaching 400 kHz to help reconcile conflicts in the historical data. Data were acquired using piezoresistive silicon pressure transducers effective at low- and mid-range frequencies, supplemented by piezoelectric quartz sensors to detect high frequency events, and combined into a single curve describing the wall pressure spectrum. Attenuation at high frequencies due to limited spatial resolution was a dominant problem, but the well-known Corcos correction successfully recovered the true amplitude within its range of applicability, revealing the ω-1 dependence for fluctuations within the logarithmic region of the boundary layer. Wind tunnel noise and vibration were removed by a noise cancellation algorithm based upon adaptive filtering, showing the power spectra are essentially flat at low frequency and do not exhibit the theorized ω2 dependence. The integrated pressure fluctuation intensities are appreciably greater than the historical supersonic database when data corrections are applied, but consistent when neglected, suggesting that past experiments may be biased low.

Conditions have been found whereby it is possible to reversibly store >11 wt% hydrogen through the direct hydrogenation of MgB2 to Mg(BH4)2. © 2010 The Royal Society of Chemistry.

A multi-group cross section collapsing code, YGROUP, has been developed to speed up deterministic particle transport simulations by reducing the number of discrete energy groups while maintaining computational transport accuracy. The YGROUP code leverages previous studies based on the "contributon" approach to automate group selection. First, forward and adjoint deterministic transport calculations are performed on a smaller problem model, or on one section of a large problem model representative of problem physics using a fine group structure. Then, the calculated forward flux and adjoint function moments are used by YGROUP to collapse the fine group cross section library and generate a problem-dependent broad group cross section library. Finally, the broad group library is used for new transport calculations on the full scale/refined problem model. YGROUP provides several weighting options to collapse the cross section library, including flat, flux, and contributon (the product of forward flux and scalar adjoint moments). Users can also specify fine groups in specific energy ranges of interest to be reserved after collapsing. YGROUP also can be used to evaluate the Feynman-Y asymptote characterizing neutron multiplicity.

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