Publications

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Increasing demands on the complexity of scientific models coupled with increasing demands for their scalability are placing programming models on equal footing with the numerical methods they implement in terms of significance. A recurring theme across several major scientific software development projects involves defining abstract data types (ADTs) that closely mimic mathematical abstractions such as scalar, vector, and tensor fields. In languages that support user-defined operators and/or overloading of intrinsic operators, coupling ADTs with a set of algebraic and/or integro-differential operators results in an ADT calculus. This talk will analyze ADT calculus using three tool sets: object-oriented design metrics, computational complexity theory, and information theory. It will be demonstrated that ADT calculus leads to highly cohesive, loosely coupled abstractions with code-size-invariant data dependencies and minimal information entropy. The talk will also discuss how these results relate to software flexibility and robustness.

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A Laboratory-Directed Research and Development project was initiated in 2005 to investigate Human Performance Modeling in a System of Systems analytic environment. SAND2006-6569 and SAND2006-7911 document interim results from this effort; this report documents the final results. The problem is difficult because of the number of humans involved in a System of Systems environment and the generally poorly defined nature of the tasks that each human must perform. A two-pronged strategy was followed: one prong was to develop human models using a probability-based method similar to that first developed for relatively well-understood probability based performance modeling; another prong was to investigate more state-of-art human cognition models. The probability-based modeling resulted in a comprehensive addition of human-modeling capability to the existing SoSAT computer program. The cognitive modeling resulted in an increased understanding of what is necessary to incorporate cognition-based models to a System of Systems analytic environment.

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The authors have developed a treatment process to improve the etch resistance of an electron beam lithography resist (ZEP 520A) to allow direct pattern transfer from the resist into a hard mask using plasma etching without a metal lift-off process. When heated to 90 C and exposed for 17 min to a dose of approximately 8 mW/cm{sup 2} at 248 nm, changes occur in the resist that are observable using infrared spectroscopy. These changes increase the etch resistance of ZEP 520A to a CF{sub 4}/O{sub 2} plasma. This article will document the observed changes in the improved etch resistance of the ZEP 520A electron beam resist.

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This project uses advanced ceramic processes to fabricate large, optical-quality, polycrystalline lanthanum halide scintillators to replace small single crystals produced by the conventional Bridgman growth method. The new approach not only removes the size constraint imposed by the growth method, but also offers the potential advantages of both reducing manufacturing cost and increasing production rate. The project goal is to fabricate dense lanthanum halide ceramics with a preferred crystal orientation by applying texture engineering and solid-state conversion to reduce the thermal mechanical stress in the ceramic and minimize scintillation light scattering at grain boundaries. Ultimately, this method could deliver the sought-after high sensitivity and <3% energy resolution at 662 keV of lanthanum halide scintillators and unleash their full potential for advanced gamma ray detection, enabling rapid identification of radioactive materials in a variety of practical applications. This report documents processing details from powder synthesis, seed particle growth, to final densification and texture development of cerium doped lanthanum bromide (LaBr{sub 3}:Ce{sup +3}) ceramics. This investigation demonstrated that: (1) A rapid, flexible, cost efficient synthesis method of anhydrous lanthanum halides and their solid solutions was developed. Several batches of ultrafine LaBr{sub 3}:Ce{sup +3} powder, free of oxyhalide, were produced by a rigorously controlled process. (2) Micron size ({approx} 5 {micro}m), platelet shape LaBr{sub 3} seed particles of high purity can be synthesized by a vapor phase transport process. (3) High aspect-ratio seed particles can be effectively aligned in the shear direction in the ceramic matrix, using a rotational shear-forming process. (4) Small size, highly translucent LaBr{sub 3} (0.25-inch diameter, 0.08-inch thick) samples were successfully fabricated by the equal channel angular consolidation process. (5) Large size, high density, translucent LaBr{sub 3} ceramics samples (3-inch diameter, > 1/8-inch thick) were fabricated by hot pressing, demonstrating the superior manufacturability of the ceramic approach over single crystal growth methods in terms of size capability and cost. (6) Despite all these advances, evidence has shown that LaBr{sub 3} is thermally unstable at temperatures required for the densification process. This is particularly true for material near the surface where lattice defects and color centers can be created as bromine becomes volatile at high temperatures. Consequently, after densification these samples made using chemically prepared ultrafine powders turned black. An additional thermal treatment in a flowing bromine condition proved able to reduce the darkness of the surface layer for these densified samples. These observations demonstrated that although finer ceramic powders are desirable for densification due to a stronger driving force from their large surface areas, the same desirable factor can lead to lattice defects and color centers when these powders are densified at higher temperatures where material near the surface becomes thermally unstable.

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There is a need to generate magnetic fields both above and below 1 megagauss (100 T) with compact generators for laser-plasma experiments in the Beamlet and Petawatt test chambers for focused research on fundamental properties of high energy density magnetic plasmas. Some of the important topics that could be addressed with such a capability are magnetic field diffusion, particle confinement, plasma instabilities, spectroscopic diagnostic development, material properties, flux compression, and alternate confinement schemes, all of which could directly support experiments on Z. This report summarizes a two-month study to develop preliminary designs of magnetic field generators for three design regimes. These are, (1) a design for a relatively low-field (10 to 50 T), compact generator for modest volumes (1 to 10 cm3), (2) a high-field (50 to 200 T) design for smaller volumes (10 to 100 mm3), and (3) an extreme field (greater than 600 T) design that uses flux compression. These designs rely on existing Sandia pulsed-power expertise and equipment, and address issues of magnetic field scaling with capacitor bank design and field inductance, vacuum interface, and trade-offs between inductance and coil designs.

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Erbium dihydride Er(H,D,T){sub 2} is a fluorite structure rare-earth dihydride useful for the storage of hydrogen isotopes in the solid state. However, thermodynamic predictions indicate that erbium oxide formation will proceed readily during processing, which may detrimentally contaminate Er(H,D,T){sub 2} films. In this work, transmission electron microscopy (TEM) techniques including energy-dispersive x-ray spectroscopy, energy-filtered TEM, selected area electron diffraction, and high-resolution TEM are used to examine the manifestation of oxygen contamination in ErD{sub 2} thin films. An oxide layer {approx}30-130 nm thick was found on top of the underlying ErD{sub 2} film, and showed a cube-on-cube epitaxial orientation to the underlying ErD{sub 2}. Electron diffraction confirmed the oxide layer to be Er{sub 2}O{sub 3}. While the majority of the film was observed to have the expected fluorite structure for ErD{sub 2}, secondary diffraction spots suggested the possibility of either nanoscale oxide inclusions or hydrogen ordering. In situ heating experiments combined with electron diffraction ruled out the possibility of hydrogen ordering, so epitaxial oxide nanoinclusions within the ErD{sub 2} matrix are hypothesized. TEM techniques were applied to examine this oxide nanoinclusion hypothesis.

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The objective of the experimental effort is to provide a model particle system that will enable modeling of the macroscopic rheology from the interfacial and environmental structure of the particles and solvent or melt as functions of applied shear and volume fraction of the solid particles. This chapter describes the choice of the model particle system, methods for synthesis and characterization, and results from characterization of colloidal dispersion, particle film formation, and the shear and oscillatory rheology in the system. Surface characterization of the grafted PDMS interface, dispersion characterization of the colloids, and rheological characterization of the dispersions as a function of volume fraction were conducted.

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In the title compound, C{sub 27}H{sub 17}N{sub 3}O{sub 4}, the azo group displays a trans conformation and the dihedral angles between the central benzene ring and the pendant anthracene and nitrobenzene rings are 82.94 (7) and 7.30 (9){sup o}, respectively. In the crystal structure, weak C-H...O hydrogen bonds, likely associated with a dipole moment present on the molecule, help to consolidate the packing.

This one-year exploratory LDRD aims to provide fundamental understanding of the mechanism of CO₂ scrubbing platforms that will reduce green house gas emission and mitigate the effect of climate change. The project builds on the team member's expertise developed in previous LDRD projects to study the capture or preferential retention of CO₂ in nanoporous membranes and on metal oxide surfaces. We apply Density Functional Theory and ab initio molecular dynamics techniques to model the binding of CO₂ on MgO and CaO (100) surfaces and inside water-filled, amine group functionalized silica nanopores. The results elucidate the mechanisms of CO₂ trapping and clarify some confusion in the literature. Our work identifies key future calculations that will have the greatest impact on CO₂ capture technologies, and provides guidance to science-based design of platforms that can separate the green house gas CO₂ from power plant exhaust or even from the atmosphere. Experimentally, we modify commercial MFI zeolite membranes and find that they preferentially transmit H₂ over CO₂ by a factor of 34. Since zeolite has potential catalytic capability to crack hydrocarbons into CO₂ and H₂, this finding paves the way for zeolite membranes that can convert biofuel into H₂ and separate the products all in one step.

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The primary function of the Gamma Detector Response and Analysis Software (GADRAS) is the solution of inverse radiation transport problems, by which the configuration of an unknown radiation source is inferred from one or more measured radiation signatures. GADRAS was originally developed for the analysis of gamma spectrometry measurements. During fiscal years 2007 and 2008, GADRAS was augmented to implement the simultaneous analysis of neutron multiplicity measurements. This report describes the radiation transport methods developed to implement this new capability. This work was performed at the direction of the National Nuclear Security Administration's Office of Nonproliferation Research and Development. It was executed as an element of the Proliferation Detection Program's Simulation, Algorithm, and Modeling element.

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We report on the work done in the late-start LDRD Using Emulation and Simulation to Understand the Large-Scale Behavior of the Internet. We describe the creation of a research platform that emulates many thousands of machines to be used for the study of large-scale inter-net behavior. We describe a proof-of-concept simple attack we performed in this environment. We describe the successful capture of a Storm bot and, from the study of the bot and further literature search, establish large-scale aspects we seek to understand via emulation of Storm on our research platform in possible follow-on work. Finally, we discuss possible future work.

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Intensified charge-coupled devices (ICCDs) are used extensively in many scientific and engineering environments to image weak or temporally short optical events. To optimize the quantum efficiency of light collection, many of these devices are chosen to have characteristic intensifier gate times that are relatively slow, on the order of tens of nanoseconds. For many measurements associated with nanosecond laser sources, such as scattering-based diagnostics and most laser-induced fluorescence applications, the signals rise and decay sufficiently fast during and after the laser pulse that the intensifier gate may be set to close after the cessation of the signal and still effectively reject interferences associated with longer time scales. However, the relatively long time scale and complex temporal response of laser-induced incandescence (LII) of nanometer-sized particles (such as soot) offer a difficult challenge to the use of slow-gating ICCDs for quantitative measurements. In this paper, ultraviolet Rayleigh scattering imaging is used to quantify the irising effect of a slow-gating scientific ICCD camera, and an analysis is conducted of LII image data collected with this camera as a function of intensifier gate width. The results demonstrate that relatively prompt LII detection, generally desirable to minimize the influences of particle size and local gas pressure and temperature on measurements of the soot volume fraction, is strongly influenced by the irising effect of slow-gating ICCDs.

Using a two-step method of plasma and wet chemical etching, we demonstrate smooth, vertical facets for use in Al{sub x} Ga{sub 1-x} N-based deep-ultraviolet laser-diode heterostructures where x = 0 to 0.5. Optimization of plasma-etching conditions included increasing both temperature and radiofrequency (RF) power to achieve a facet angle of 5 deg from vertical. Subsequent etching in AZ400K developer was investigated to reduce the facet surface roughness and improve facet verticality. The resulting combined processes produced improved facet sidewalls with an average angle of 0.7 deg from vertical and less than 2-nm root-mean-square (RMS) roughness, yielding an estimated reflectivity greater than 95% of that of a perfectly smooth and vertical facet.

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The OH concentration in the Cl-initiated oxidation of cyclohexane has been measured between 6.5-20.3 bar and in the 586-828 K temperature range by a pulsed-laser photolytic initiation--laser-induced fluorescence method. The experimental OH profiles are modeled by using a master-equation-based kinetic model as well as a comprehensive literature mechanism. Below 700 K OH formation takes place on two distinct time-scales, one on the order of microseconds and the other over milliseconds. Detailed modeling demonstrates that formally direct chemical activation pathways are responsible for the OH formation on short timescales. These results establish that formally direct pathways are surprisingly important even for relatively large molecules at the pressures of practical combustors. It is also shown that remaining discrepancies between model and experiment are attributable to low-temperature chain branching from the addition of the second oxygen to hydroperoxycyclohexyl radicals.

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The reported theoretical 'average binding of 0.20 eV per C atom, relative to a free graphene sheet and a clean metal slab' was an artifact of faulty evaluation of the energy of the free graphene sheet. Escaping our notice, the error occurred in the electron-density update algorithm, where two of six nearly degenerate eigenvectors were dropped [1]. With the error corrected, the computed binding energy of the graphene layer to Ir(111), is much smaller, just 0.18 eV per moire unit cell, or 0.9 meV per C atom. With a finer, 3 x 3 sample of the 10 x 10 graphene supercell's surface Brillouin zone, it increases to 2 meV/C atom. The cost of having to stretch the graphene sheet by {approx}0.3 linear percent to make it epitaxial on an underlying 9 x 9 Ir(111) supercell is incorporated in these values.

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We present a nanoscale color detector based on a single-walled carbon nanotube functionalized with azobenzene chromophores, where the chromophores serve as photoabsorbers and the nanotube as the electronic read-out. By synthesizing chromophores with specific absorption windows in the visible spectrum and anchoring them to the nanotube surface, we demonstrate the controlled detection of visible light of low intensity in narrow ranges of wavelengths. Our measurements suggest that upon photoabsorption, the chromophores isomerize from the ground state trans configuration to the excited state cis configuration, accompanied by a large change in dipole moment, changing the electrostatic environment of the nanotube. All-electron ab initio calculations are used to study the chromophore-nanotube hybrids and show that the chromophores bind strongly to the nanotubes without disturbing the electronic structure of either species. Calculated values of the dipole moments support the notion of dipole changes as the optical detection mechanism.

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This paper presents a new methodology for analyzing complex networks in which the network of interest is first abstracted to a much simpler (but equivalent) representation, the required analysis is performed using the abstraction, and analytic conclusions are then mapped back to the original network and interpreted there. We begin by identifying a broad and important class of complex networks which admit abstractions that are simultaneously dramatically simplifying and property preserving we call these aggressive abstractions -- and which can therefore be analyzed using the proposed approach. We then introduce and develop two forms of aggressive abstraction: 1.) finite state abstraction, in which dynamical networks with uncountable state spaces are modeled using finite state systems, and 2.) onedimensional abstraction, whereby high dimensional network dynamics are captured in a meaningful way using a single scalar variable. In each case, the property preserving nature of the abstraction process is rigorously established and efficient algorithms are presented for computing the abstraction. The considerable potential of the proposed approach to complex networks analysis is illustrated through case studies involving vulnerability analysis of technological networks and predictive analysis for social processes.

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Tonopah Test Range (TTR) in Nevada and Kauai Test Facility (KTF) in Hawaii are government-owned, contractor-operated facilities operated by Sandia Corporation (Sandia), a wholly owned subsidiary of Lockheed Martin Corporation. The U.S. Department of Energy (DOE)/National Nuclear Security Administration (NNSA), through the Sandia Site Offi ce (SSO), in Albuquerque, NM, administers the contract and oversees contractor operations at TTR and KTF. Sandia manages and conducts operations at TTR in support of the DOE/NNSA’s Weapons Ordnance Program and has operated the site since 1957. Washington Group International subcontracts to Sandia in administering most of the environmental programs at TTR. Sandia operates KTF as a rocket preparation launching and tracking facility. This Annual Site Environmental Report (ASER) summarizes data and the compliance status of the environmental protection and monitoring program at TTR and KTF through Calendar Year (CY) 2007. The compliance status of environmental regulations applicable at these sites include state and federal regulations governing air emissions, wastewater effluent, waste management, terrestrial surveillance, and Environmental Restoration (ER) cleanup activities. Sandia is responsible only for those environmental program activities related to its operations. The DOE/NNSA/Nevada Site Offi ce (NSO) retains responsibility for the cleanup and management of ER TTR sites. Currently, there are no ER Sites at KTF. Environmental monitoring and surveillance programs are required by DOE Order 450.1, Environmental Protection Program (DOE 2007a) and DOE Manual 231.1-1A, Environment, Safety, and Health Reporting Manual (DOE 2007).

This report summarizes the measurements and model predictions for a series of tests supported by the U.S. Department of Energy that were performed using the recently constructed Sandia Brayton Loop (SBL-30). From the test results we have developed steady-state power operating curves, controls methodologies, and transient data for normal and off-normal behavior, such as loss of load events, and for decay heat removal conditions after shutdown. These tests and models show that because the turbomachinery operates off of the temperature difference (between the heat source and the heat sink), that the turbomachinery can continue to operate (off of sensible heat) for long periods of time without auxiliary power. For our test hardware, operations up to one hour have been observed. This effect can provide significant operations and safety benefits for nuclear reactors that are coupled to a Brayton cycles because the operating turbomachinery continues to provide cooling to the reactor. These capabilities mean that the decay-heat removal can be accommodated by properly managing the electrical power produced by the generator/alternator. In some conditions, it may even be possible to produce sufficient power to continue operating auxiliary systems including the waste heat circulatory system. In addition, the Brayton plant impacts the consequences of off-normal and accident events including loss of load and loss of on-site power. We have observed that for a loss of load or a loss of on-site power event, with a reactor scram, the transient consists initially of a turbomachinery speed increase to a new stable operating point. Because the turbomachinery is still spinning, the reactor is still being cooled provided the ultimate heat sink remains available. These highly desirable operational characteristics were observed in the Sandia Brayton loop. This type of behavior is also predicted by our models. Ultimately, these results provide the designers the opportunity to design gas cooled reactor Brayton plants such that the system is inherently capable of dealing with a variety of off-normal and accident conditions.

Low-pressure (1–4 atm) cylindrical ³He counters are widely used as neutron detectors. These detectors are relatively large (1–2.5 cm diameter) and can be subject to noise induced by microphonics. Meanwhile, new advancements in micro-fabrication are enabling the manufacture of high-pressure (over 3000 atm) micro-capillaries (~100 µm diameter). Can these micro-capillaries be used as accurate and high-efficiency ³He counters? To answer these questions, we have developed a mathematical model/computer simulation. Our model shows that such capillaries have the potential for being high-efficiency neutron spectrometers capable of resolving not only energy, but also angle of incidence for fixed sources. Finally, we benchmark the model against published results and extrapolate spectra to the pressures of interest.

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As the expectations of physicians and patients have matured, the desire to utilize advanced CMOS technologies to provide increasingly sophisticated therapeutic and diagnostic capabilities has grown. This has pushed the high reliability implantable device business into the use of processes that are much more susceptible to soft error events than in the past. This paper discusses experimental and modeling results of logic upsets in a 0.25μm CMOS IC process. © 2008 IEEE.

The next generation 850 nm datacom VCSEL to go into production will be the 17 G VCSEL. It is not certain that direct modulation will be suitable given the reliability, supply voltage, and temperature range required. This paper is a first look at VCSELs designed and targeted for production 17 G use. The design is discussed and LIV and small signal frequency response is presented. © 2008 Optical Society of America.

We present terahertz metamaterials fabricated on large-area, free-standing thin (≤1 μm) silicon nitride membranes with the aim of reducing dielectric losses, enhancing metamaterial sensing capabilities, and enabling flexible and conformable designs. © 2008 Optical Society of America.

Polymeric foam systems are widely used in industrial applications due to their low weight and abilities to thermally insulate and isolate vibration. However, processing of these foams is still not well understood at a fundamental level. The precursor foam of interest starts off as a liquid phase emulsion of blowing agent in a thermosetting polymer. As the material is heated either by an external oven or by the exothermic reaction from internal polymerization of the suspending fluid, the blowing agent boils to produce gas bubbles and a foamy material. A series of experiments have been performed to allow observation of the foaming process and the collection of temperature, rise rate, and microstructural data. Microfocus video is used in conjunction with particle image velocimetry (PIV) to elucidate the boundary condition at the wall. These data provide input to a continuum level finite element model of the blowing process. PIV is used to measure the slip velocity of foams with a volume fraction range of 0.50 to 0.71. These results are in agreement with theoretical predictions which suggest that at high volume fractions the bubbles would exhibit jamming behavior and slip at the wall. At these volume fractions, the slip velocity profile has a shear profile shape near the side walls and a plug flow shape at the center. The shape of the velocity profile is in agreement with previous experimental work investigating different foam systems. As time increases, the available blowing agent decreases, the volume fraction increases, the viscosity increases, and the average slip velocity decreases, but the slip velocity profile maintains the plug-shear shape. © 2008 American Institute of Physics.

X-ray powder diffraction data for ErH2-x Dx formed by hydrogen (i.e., protium)-deuterium loading of Er metal are reported. Lattice parameters for the varying hydrogen-deuterium compositions followed Vergard's law behavior. The cubic lattice parameter at room temperature for ErH2-x Dx obeys a linear relationship according to the formula a=5.1287-1.1120× 10-4 x, where a is the lattice parameter of the fluorite-type structure and x is the mole percent of deuterium. Microstrain measurements suggest a possible ordering of hydrogen and deuterium in the composition ErH1 D1. © 2008 International Centre for Diffraction Data.

An analytical model of gaseous and liquid-phase radon transport through soils is derived for environmental modeling of landfills containing uranium mill tailings or Ra-226 sources. Processes include radon diffusion in both the gas and liquid phases, advection of soluble radon in percolating water, radioactive decay, equilibrium partitioning between gas and liquid phases, and emanation from different source terms. A probabilistic framework for the radon-transport model is introduced that provides uncertainty and sensitivity analyses for risk-based assessments. Uncertainty analyses are used to compare simulated performance metrics (e.g., radon surface flux) against regulatory standards. Sensitivity analyses are used to identify key parameters and processes that impact the variability of the simulated results. The models and analyses are illustrated with a probabilistic performance assessment of the Mixed Waste Landfill at Sandia National Laboratories in Albuquerque, NM. © 2008 Elsevier Ltd. All rights reserved.

Sandia National Laboratories NLS (1064 nm) and Z-Beamlet (527 nm) pulsed lasers @ ∼ 100 GW/cm2 and 10 TW/cm2 were used to attain pressures at 20 - 525 GPa on a variety of metallic and mineral targets. A simple, inexpensive and innovative electro-optical real-time methodology monitored rear surface mechanical deformation and associated particle and shock wave velocities that differ considerably between metals and non-metals. A reference calibration metal (Aluminum) and a reference non-metal (graphite) were used to demonstrate the validity of this methodology. Normative equations of state and momentum coupling coefficients were obtained for dunite, carbonaceous meteorites, graphite, iron and nickel. These experimental results on inhomogeneous materials can be applied to a variety of high energy density interactions involving stellar and planetary material formation, dynamic interactions, geophysical models, space propulsion systems, orbital debris, materials processing, near-earth space (lunar and asteroid) resource recovery, and near-earth object mitigation models.

The Na+ and [Cu(en)2(H2O) 2]2+ (en = ethylenediamine) salt of a pseudosandwich-type heteropolyniobate forms upon prolonged heating of Cu(NO3)2 and hydrated Na14[(SiOH)2Si2Nb 16O54] in a mixed water-en solution. The structure [a = 14.992(2) Å, b = 25.426(4) Å, c = 30.046(4) Å, orthorhombic, Pnn2, R1 = 6.04%, based on 25869 unique reflections] consists of two [Na(SiOH)2Si2Nb16O54]13- units linked by six sodium cations, and this sandwich is charge-balanced by five [Cu(en)2(H2O)2]2+ complexes, seven protons, and three additional sodium atoms (all per a sandwich-type cluster). Diffuse-reflectance UV-vis indicates that there is a λmax at 383 nm for the CuII d-d transition and the 29Si MAS NMR spectrum has two peaks at -78.2 ppm (151 Hz) and -75.5 ppm (257 Hz) for the two pairs of symmetry-equivalent internal [SiO4]4- and external [SiO3(OH)]3- tetrahedra, respectively. Unlike tungsten-based sandwich-type complexes, the [Na(SiOH)2Si 2Nb16O54]13- units are linked exclusively by Na+ instead of one or more d-electron metals. © 2008 American Chemical Society.

One powerful method for measuring the motion of microelectromechanical systems (MEMS) relies on a Laser Doppler Vibrometer (LDV) focused through an optical microscope. Recent data taken under a very simple and common condition demonstrate that the velocity signal produced by the LDV with an optical microscope may be different from the velocity signal produced by the LDV without a microscope. This is especially important if one wishes to estimate acceleration by differentiating velocity. In this study, the time derivatives of LDV signals are compared against the signal from an accelerometer when the LDV is focused through an optical microscope and without the microscope system. The signal from the LDV without the microscope is almost identical to the accelerometer signal. In contrast, the signal from the LDV with the microscope exhibits a nonlinear relationship with the accelerometer signal. Both the LDV and the accelerometer were measuring a sinusoidal velocity generated by an electromechanical shaker. The Fourier transform of the acceleration from the LDV with the microscope shows a multitude of high harmonics of the excitation frequency, which have much higher amplitudes than the harmonics present in the accelerometer signal. Without the microscope, the LDV gives a much less distorted sinusoidal signal, even after time differentiation. The distortion of the signal from the LDV is periodic, with the same period as the sinusoidal drive signal. The largest distortion occurs near points of maximum negative acceleration, corresponding to the positive displacement peak of the sinusoidal oscillation. Because the measured oscillation is out of plane, pseudo-vibrations caused by speckle noise do not explain the distortion. Instead, the distortion appears to be caused by the optics of the microscope.

The goal of this evaluation report is to provide the information necessary to improve the effectiveness of the ITC provided to the International Atomic Energy Agency Member States. This report examines ITC-20 training content, delivery methods, scheduling, and logistics. Ultimately, this report evaluates whether the course provides the knowledge and skills necessary to meet the participants needs in the protection of nuclear materials and facilities.

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This report presents a test protocol for screening capacitors dielectrics for charge loss due to ionizing radiation. The test protocol minimizes experimental error and provides a test method that allows comparisons of different dielectric types if exposed to the same environment and if the same experimental technique is used. The test acceptance or screening method is fully described in this report. A discussion of technical issues and possible errors and uncertainties is included in this report also.

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In this paper the performance of the LiFeBatt Li-ion cell was measured using a number of tests including capacity measurements, capacity as a function of temperature, ohmic resistance, spectral impedance, high power partial state of charge (PSOC) pulsed cycling, pulse power measurements, and an over-charge/voltage abuse test. The goal of this work was to evaluate the performance of the iron phosphate Li-ion battery technology for utility applications requiring frequent charges and discharges, such as voltage support, frequency regulation, and wind farm energy smoothing. Test results have indicated that the LiFeBatt battery technology can function up to a 10C{sub 1} discharge rate with minimal energy loss compared to the 1 h discharge rate (1C). The utility PSOC cycle test at up to the 4C{sub 1} pulse rate completed 8,394 PSOC pulsed cycles with a gradual loss in capacity of 10 to 15% depending on how the capacity loss is calculated. The majority of the capacity loss occurred during the initial 2,000 cycles, so it is projected that the LiFeBatt should PSOC cycle well beyond 8,394 cycles with less than 20% capacity loss. The DC ohmic resistance and AC spectral impedance measurements also indicate that there were only very small changes after cycling. Finally, at a 1C charge rate, the over charge/voltage abuse test resulted in the cell venting electrolyte at 110 C after 30 minutes and then open-circuiting at 120 C with no sparks, fire, or voltage across the cell.

This document describes the sediment transport subroutines and input files for the Sandia National Laboratories Environmental Fluid Dynamics Code (SNL-EFDC). Detailed descriptions of the input files containing data from Sediment Erosion at Depth flume (SEDflume) measurements are provided along with the description of the source code implementing sediment transport. Both the theoretical description of sediment transport employed in SNL-EFDC and the source code are described. This user manual is meant to be used in conjunction with the EFDC manual (Hamrick 1996) because there will be no reference to the hydrodynamics in EFDC. Through this document, the authors aim to provide the necessary information for new users who wish to implement sediment transport in EFDC and obtain a clear understanding of the source code.

U.S. Nuclear Regulatory Commission nuclear power plant licensees and new reactor applicants are required to provide protection of their plants against radiological sabotage, including the placement of vital equipment in vital areas. This document describes a systematic process for the identification of the minimum set of areas that must be designated as vital areas in order to ensure that all radiological sabotage scenarios are prevented. Vital area identification involves the use of logic models to systematically identify all of the malicious acts or combinations of malicious acts that could lead to radiological sabotage. The models available in the plant probabilistic risk assessment and other safety analyses provide a great deal of the information and basic model structure needed for the sabotage logic model. Once the sabotage logic model is developed, the events (or malicious acts) in the model are replaced with the areas in which the events can be accomplished. This sabotage area logic model is then analyzed to identify the target sets (combinations of areas the adversary must visit to cause radiological sabotage) and the candidate vital area sets (combinations of areas that must be protected against adversary access to prevent radiological sabotage). Any one of the candidate vital area sets can be selected for protection. Appropriate selection criteria will allow the licensee or new reactor applicant to minimize the impacts of vital area protection measures on plant safety, cost, operations, or other factors of concern.

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