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Nuclear Energy Advanced Modeling and Simulation (NEAMS) Waste Integrated Performance and Safety Codes (IPSC) : FY10 development and integration

Freeze, Geoffrey A.; Arguello, Jose G.; Bouchard, Julie F.; Criscenti, Louise C.; Dewers, Thomas D.; Edwards, Harold C.; Sassani, David C.; Schultz, Peter A.; Wang, Yifeng

This report describes the progress in fiscal year 2010 in developing the Waste Integrated Performance and Safety Codes (IPSC) in support of the U.S. Department of Energy (DOE) Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign. The goal of the Waste IPSC is to develop an integrated suite of computational modeling and simulation capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive waste storage or disposal system. The Waste IPSC will provide this simulation capability (1) for a range of disposal concepts, waste form types, engineered repository designs, and geologic settings, (2) for a range of time scales and distances, (3) with appropriate consideration of the inherent uncertainties, and (4) in accordance with robust verification, validation, and software quality requirements. Waste IPSC activities in fiscal year 2010 focused on specifying a challenge problem to demonstrate proof of concept, developing a verification and validation plan, and performing an initial gap analyses to identify candidate codes and tools to support the development and integration of the Waste IPSC. The current Waste IPSC strategy is to acquire and integrate the necessary Waste IPSC capabilities wherever feasible, and develop only those capabilities that cannot be acquired or suitably integrated, verified, or validated. This year-end progress report documents the FY10 status of acquisition, development, and integration of thermal-hydrologic-chemical-mechanical (THCM) code capabilities, frameworks, and enabling tools and infrastructure.

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TYPE SAND Report YEAR 2011
DOIOSTI

Final report for %22High performance computing for advanced national electric power grid modeling and integration of solar generation resources%22, LDRD Project No. 149016

Schoenwald, David A.; Richardson, Bryan T.; Riehm, Andrew C.; Wolfenbarger, Paul W.; Adams, Brian M.; Reno, Matthew J.; Hansen, Clifford H.; Oldfield, Ron A.; Stamp, Jason E.; Stein, Joshua S.; Hoekstra, Robert J.; Nelson, Jeffrey S.; Munoz-Ramos, Karina M.; McLendon, William C.; Russo, Thomas V.; Phillips, Laurence R.

Design and operation of the electric power grid (EPG) relies heavily on computational models. High-fidelity, full-order models are used to study transient phenomena on only a small part of the network. Reduced-order dynamic and power flow models are used when analysis involving thousands of nodes are required due to the computational demands when simulating large numbers of nodes. The level of complexity of the future EPG will dramatically increase due to large-scale deployment of variable renewable generation, active load and distributed generation resources, adaptive protection and control systems, and price-responsive demand. High-fidelity modeling of this future grid will require significant advances in coupled, multi-scale tools and their use on high performance computing (HPC) platforms. This LDRD report demonstrates SNL's capability to apply HPC resources to these 3 tasks: (1) High-fidelity, large-scale modeling of power system dynamics; (2) Statistical assessment of grid security via Monte-Carlo simulations of cyber attacks; and (3) Development of models to predict variability of solar resources at locations where little or no ground-based measurements are available.

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TYPE SAND Report YEAR 2011
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Programmed assembly of nanoscale structures using peptoids

Robinson, David R.; Buffleben, George M.; Kent, Michael S.

Sequence-specific polymers are the basis of the most promising approaches to bottom-up programmed assembly of nanoscale materials. Examples include artificial peptides and nucleic acids. Another class is oligo(N-functional glycine)s, also known as peptoids, which permit greater sidegroup diversity and conformational control, and can be easier to synthesize and purify. We have developed a set of peptoids that can be used to make inorganic nanoparticles more compatible with biological sequence-specific polymers so that they can be incorporated into nucleic acid or other biologically based nanostructures. Peptoids offer degrees of modularity, versatility, and predictability that equal or exceed other sequence-specific polymers, allowing for rational design of oligomers for a specific purpose. This degree of control will be essential to the development of arbitrarily designed nanoscale structures.

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TYPE SAND Report YEAR 2011
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Probabilistic models for feedback systems

Grace, Matthew G.

In previous work, we developed a Bayesian-based methodology to analyze the reliability of hierarchical systems. The output of the procedure is a statistical distribution of the reliability, thus allowing many questions to be answered. The principal advantage of the approach is that along with an estimate of the reliability, we also can provide statements of confidence in the results. The model is quite general in that it allows general representations of all of the distributions involved, it incorporates prior knowledge into the models, it allows errors in the 'engineered' nodes of a system to be determined by the data, and leads to the ability to determine optimal testing strategies. In this report, we provide the preliminary steps necessary to extend this approach to systems with feedback. Feedback is an essential component of 'complexity' and provides interesting challenges in modeling the time-dependent action of a feedback loop. We provide a mechanism for doing this and analyze a simple case. We then consider some extensions to more interesting examples with local control affecting the entire system. Finally, a discussion of the status of the research is also included.

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TYPE SAND Report YEAR 2011
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Sandia National Laboratories, California Hazardous Materials Management Program annual report

Brynildson, Mark E.

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

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TYPE SAND Report YEAR 2011
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International Border Management Systems (IBMS) Program : visions and strategies

Stapp, Ashley M.; Mohagheghi, Amir H.

Sandia National Laboratories (SNL), International Border Management Systems (IBMS) Program is working to establish a long-term border security strategy with United States Central Command (CENTCOM). Efforts are being made to synthesize border security capabilities and technologies maintained at the Laboratories, and coordinate with subject matter expertise from both the New Mexico and California offices. The vision for SNL is to provide science and technology support for international projects and engagements on border security.

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TYPE SAND Report YEAR 2011
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Wind turbine composite blade manufacturing : the need for understanding defect origins, prevalence, implications and reliability

Cairns, Douglas S.; Riddle, Trey; Nelson, Jared

Renewable energy is an important element in the US strategy for mitigating our dependence on non-domestic oil. Wind energy has emerged as a viable and commercially successful renewable energy source. This is the impetus for the 20% wind energy by 2030 initiative in the US. Furthermore, wind energy is important on to enable a global economy. This is the impetus for such rapid, recent growth. Wind turbine blades are a major structural element of a wind turbine blade. Wind turbine blades have near aerospace quality demands at commodity prices; often two orders of magnitude less cost than a comparable aerospace structure. Blade failures are currently as the second most critical concern for wind turbine reliability. Early blade failures typically occur at manufacturing defects. There is a need to understand how to quantify, disposition, and mitigate manufacturing defects to protect the current wind turbine fleet, and for the future. This report is an overview of the needs, approaches, and strategies for addressing the effect of defects in wind turbine blades. The overall goal is to provide the wind turbine industry with a hierarchical procedure for addressing blade manufacturing defects relative to wind turbine reliability.

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TYPE SAND Report YEAR 2011
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Radius of influence for a cosmic-ray soil moisture probe : theory and Monte Carlo simulations

Desilets, Darin M.

The lateral footprint of a cosmic-ray soil moisture probe was determined using diffusion theory and neutron transport simulations. The footprint is radial and can be described by a single parameter, an e-folding length that is closely related to the slowing down length in air. In our work the slowing down length is defined as the crow-flight distance traveled by a neutron from nuclear emission as a fast neutron to detection at a lower energy threshold defined by the detector. Here the footprint is defined as the area encompassed by two e-fold distances, i.e. the area from which 86% of the recorded neutrons originate. The slowing down length is approximately 150 m at sea level for neutrons detected over a wide range of energies - from 10{sup 0} to 10{sup 5} eV. Both theory and simulations indicate that the slowing down length is inversely proportional to air density and linearly proportional to the height of the sensor above the ground for heights up to 100 m. Simulations suggest that the radius of influence for neutrons >1 eV is only slightly influenced by soil moisture content, and depends weakly on the energy sensitivity of the neutron detector. Good agreement between the theoretical slowing down length in air and the simulated slowing down length near the air/ground interface support the conclusion that the footprint is determined mainly by the neutron scattering properties of air.

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TYPE SAND Report YEAR 2011
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%22Trojan Horse%22 strategy for deconstruction of biomass for biofuels production

Hadi, Masood H.

Production of renewable biofuels to displace fossil fuels currently consumed in the transportation sector is a pressing multiagency national priority (DOE/USDA/EERE). Currently, nearly all fuel ethanol is produced from corn-derived starch. Dedicated 'energy crops' and agricultural waste are preferred long-term solutions for renewable, cheap, and globally available biofuels as they avoid some of the market pressures and secondary greenhouse gas emission challenges currently facing corn ethanol. These sources of lignocellulosic biomass are converted to fermentable sugars using a variety of chemical and thermochemical pretreatments, which disrupt cellulose and lignin cross-links, allowing exogenously added recombinant microbial enzymes to more efficiently hydrolyze the cellulose for 'deconstruction' into glucose. This process is plagued with inefficiencies, primarily due to the recalcitrance of cellulosic biomass, mass transfer issues during deconstruction, and low activity of recombinant deconstruction enzymes. Costs are also high due to the requirement for enzymes and reagents, and energy-intensive cumbersome pretreatment steps. One potential solution to these problems is found in synthetic biology-engineered plants that self-produce a suite of cellulase enzymes. Deconstruction can then be integrated into a one-step process, thereby increasing efficiency (cellulose-cellulase mass-transfer rates) and reducing costs. The unique aspects of our approach are the rationally engineered enzymes which become Trojan horses during pretreatment conditions. During this study we rationally engineered Cazy enzymes and then integrated them into plant cells by multiple transformation techniques. The regenerated plants were assayed for first expression of these messages and then for the resulting proteins. The plants were then subjected to consolidated bioprocessing and characterized in detail. Our results and possible implications of this work on developing dedicated energy crops and their advantage in a consolidated bioprocessing system.

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TYPE SAND Report YEAR 2011
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Massively parallel acceleration of a document-similarity classifier to detect web attacks

Journal of Parallel and Distributed Computing

Ulmer, Craig; Gokhale, Maya; Gallagher, Brian; Top, Philip; Eliassi-Rad, Tina

This paper describes our approach to adapting a text document similarity classifier based on the Term Frequency Inverse Document Frequency (TFIDF) metric to two massively multi-core hardware platforms. The TFIDF classifier is used to detect web attacks in HTTP data. In our parallel hardware approaches, we design streaming, real time classifiers by simplifying the sequential algorithm and manipulating the classifier's model to allow decision information to be represented compactly. Parallel implementations on the Tilera 64-core System on Chip and the Xilinx Virtex 5-LX FPGA are presented. For the Tilera, we employ a reduced state machine to recognize dictionary terms without requiring explicit tokenization, and achieve throughput of 37 MB/s at a slightly reduced accuracy. For the FPGA, we have developed a set of software tools to help automate the process of converting training data to synthesizable hardware and to provide a means of trading off between accuracy and resource utilization. The Xilinx Virtex 5-LX implementation requires 0.2% of the memory used by the original algorithm. At 166 MB/s (80X the software) the hardware implementation is able to achieve Gigabit network throughput at the same accuracy as the original algorithm. © 2010 Elsevier Inc. All rights reserved.

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TYPE Journal Article YEAR 2011
ScopusOSTIDOI

First-principles full-vectorial eigenfrequency computations for axially symmetric resonators

Journal of Lightwave Technology

Kekatpure, Rohan D.

Starting from the time-harmonic Maxwell's equations in cylindrical coordinates, we derive and solve the finite-difference (FD) eigenvalue equations for determining vector modes of axially symmetric resonator structures such as disks, rings, spheres and toroids. Contrary to the most existing implementations, our FD scheme is readily adapted for both eigenmode and eigenfrequency calculations. An excellent match of the FD solutions with the analytically calculated mode indices of a microsphere resonator provides a numerical confirmation of the mode-solver accuracy. The comparison of the presented FD technique with the finite-element method highlights the relative strengths of both techniques and advances the FD mode-solver as an important tool for cylindrical resonator design. © 2010 IEEE.

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TYPE Journal Article YEAR 2011
OSTIScopus

Dislocation-pairing transitions in hot grain boundaries

Physical Review Letters

Olmsted, David L.; Buta, Dorel; Adland, Ari; Foiles, Stephen M.; Asta, Mark; Karma, Alain

We report the finding of a novel grain-boundary structural phase transition in both molecular-dynamics and phase-field-crystal simulations of classical models of bcc Fe. This transition is characterized by pairing of individual dislocations with mixed screw and edge components. We demonstrate that this type of transition is driven by a combination of factors including elastic softening, core interaction, and core disordering. At high homologous temperatures the occurrence of this transition is shown to prevent premelting at misorientation angles where it would otherwise be expected. © 2011 American Physical Society.

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TYPE Journal Article YEAR 2011
ScopusOSTI

InP substrate evaluation by MOVPE growth of lattice matched epitaxial layers

Journal of Crystal Growth

Cederberg, Jeffrey G.; Overberg, Mark E.

InP substrates form the starting point for a wide variety of semiconductor devices. The surface morphology produced during epitaxy depends critically on the starting substrate. We evaluated (1 0 0)-oriented InP wafers from three different vendors by growing thick (5 μm) lattice-matched epilayers of InP, GaInAs, and AlInAs. We assessed the surfaces with differential interference contrast microscopy and atomic force microscopy. Wafers with near singular (1 0 0) orientations produced inferior surfaces in general. Vicinal substrates with small misorientations improved the epitaxial surface for InP dramatically, reducing the density of macroscopic defects while maintaining a low RMS roughness. GaInAs and AlInAs epitaxy step-bunched forming undulations along the miscut direction. Sulfur-doped wafers were considered for singular (1 0 0) and for 0.2° misorientation toward (1 1 0). We found that mound defects observed for InP and GaInAs layers on iron-doped singular wafers were absent for singular sulfur-doped wafers. These observations support the conclusion that dislocation termination at the surface and expansion of the step spiral lead to the macroscopic defects observed. © 2010 Elsevier B.V.

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TYPE Conference YEAR 2011
ScopusOSTI

Effectiveness of modeling thin composite structures using hex shell elements

Conference Proceedings of the Society for Experimental Mechanics Series

Garcia, Ricardo M.; Tipton, David G.

This paper investigates the effectiveness of modeling thin composite structures with hex shell elements for structural dynamics simulation. The current finite element modeling method for an existing three-layer composite aerospace structure uses solid 8-noded hex elements. It is relatively expensive in terms of the number of degrees of freedom and element count. A finer mesh typically results in a more accurate solution, however, the computation time increases. Modal analysis was used to test if a single layer of hex shell elements for each material could replace multiple layers of solid hex elements, enabling computational savings. Element aspect ratio was varied on a solid hex model of a frustum part to optimize the technique. The hex shell modeling technique was then applied to the existing three-layer composite structure. The analysis results, when compared to validation data obtained from tests performed on the actual hardware, exhibit very satisfactory agreement. A single layer of hex shell elements are capable of providing solutions that are equivalent to multiple layers of hex elements. A considerable savings in element count and solution equations result. A broader understanding of modeling options for future, more efficient methods of modeling composite shell structures is also obtained. ©2010 Society for Experimental Mechanics Inc.

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TYPE Conference YEAR 2011
ScopusOSTI

Modal analysis of CX-100 rotor blade and micon 65/13 wind turbine

Conference Proceedings of the Society for Experimental Mechanics Series

White, J.R.; Adams, D.E.; Rumsey, Mark A.

At the end of 2008 the United States became the largest producer of wind energy with 25,369 MW of electricity. This accounts for 1.25% of all U.S. electricity generated and enough to power 7 million homes. As wind energy becomes a key player in power generation and in the economy, so does the performance and reliability of wind turbines. To improve both performance and reliability, smart rotor blades are being developed that collocate reference measurements, aerodynamic actuation, and control on the rotor blade. Towards the development of a smart blade, SNL has fabricated a sensored rotor blade with embedded distributed accelerometer measurements to be used with operational loading methods to estimate the rotor blade deflection and dynamic excitation. These estimates would serve as observers for future smart rotor blade control systems. An accurate model of the rotor blade was needed for the development of the operational monitoring methods. An experimental modal analysis of the SNL sensored rotor blade (a modified CX-100 rotor blade) with embedded DC accelerometers was performed when hung with free boundary conditions and when mounted to a Micon 65/13 wind turbine. The modal analysis results and results from a static pull test were used to update an existing distributed parameter CX-100 rotor analytical blade model. This model was updated using percentage error estimates from cost functions of the weighted residuals. The model distributed stiffness parameters were simultaneously updated using the static and dynamic experimental results. The model updating methods decreased all of the chosen error metrics and will be used in future work to update the edge-wise model of the rotor blade and the full turbine model. ©2010 Society for Experimental Mechanics Inc.

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TYPE Conference YEAR 2011
ScopusOSTI

A revisit to high-rate mode-ii fracture characterization of composites with Kolsky bar techniques

Conference Proceedings of the Society for Experimental Mechanics Series

Lu, Wei-Yang L.; Song, Bo S.; Jin, Huiqing J.

Nowadays composite materials have been extensively utilized in many military and industrial applications. For example, the newest Boeing 787 uses 50% composite (mostly carbon fiber reinforced plastic) in production. However, the weak delamination strength of fiber reinforced composites, when subjected to external impact such as ballistic impact, has been always potential serious threats to the safety of passengers. Dynamic fracture toughness is a critical indicator of the performance from delamination in such impact events. Quasi-static experimental techniques for fracture toughness have been well developed. For example, end notched flexure (ENF) technique, which is illustrated in Fig. 1, has become a typical method to determined mode-II fracture toughness for composites under quasi-static loading conditions. However, dynamic fracture characterization of composites has been challenging. This has resulted in conflictive and confusing conclusions in regard to strain rate effects on fracture toughness of composites.

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TYPE Conference YEAR 2011
OSTIScopus

Recent US activities on advanced He-cooled W-alloy divertor concepts for fusion power plants

Fusion Engineering and Design

Tillack, M.S.; Raffray, A.R.; Wang, X.R.; Malang, S.; Abdel-Khalik, S.; Yoda, M.; Youchison, D.

Several advanced He-cooled W-alloy divertor concepts have been considered recently for power plant applications. They range in scale from a plate configuration with characteristic dimension of the order of 1 m, to the ARIES-CS T-tube configuration with characteristic dimension of the order of 10 cm, to the EU FZK finger concept with characteristic dimension of the order of 1.5 cm. The trend in moving to smaller-scale units is aimed at minimizing the thermal stress under a given heat load; however, this is done at the expense of increasing the number of units, with a corresponding impact on the reliability of the system. The possibility of optimizing the design by combining different configurations in an integrated design, based on the anticipated divertor heat flux profile, also has been proposed. Several heat transfer enhancement schemes have been considered in these designs, including slot jet, multi-hole jet, porous media and pin arrays. This paper summarizes recent US efforts in this area, including optimization and assessment of the different concepts under power plant conditions. Analytical and experimental studies of the concepts and cooling schemes are presented. Key issues are identified and discussed to help guide future R&D, including fabrication, joining, material behavior under the fusion environment and impact of design choice on reliability. © 2010 Elsevier B.V.

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TYPE Journal Article YEAR 2011
ScopusOSTI

Measuring strength at ultrahigh strain rates

Conference Proceedings of the Society for Experimental Mechanics Series

Vogler, Tracy V.

The use of uniaxial strain ramp loading experiments to measure strength at extremely high strain rates is discussed. The technique is outlined and issues associated with it are examined. Results for 6061-T6 aluminum are presented that differ from the conventional view of strain rate sensitivity in aluminum alloys. ©2010 Society for Experimental Mechanics Inc.

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TYPE Conference YEAR 2011
OSTIScopus

Honing emotional intelligence with game-Based crucible experiences

International Journal of Game-Based Learning

Raybourn, Elaine M.

The focus of the present paper is the design of multi-player role-playing game instances as crucible experiences for the exploration of one's emotional intelligence. Subsequent sections describe the design of game-based, intercultural crucible experiences and how this design was employed for training with members of the United States Marine Corps (USMC). This work with the USMC is presented as a case study and example of the use of crucible experiences in game-based learning. Crucible experiences are learning opportunities relevant across a number of different domains and disciplines such as education, healthcare, corporate training, diplomacy, crisis management, international business, and intercultural communication. The present paper demonstrates that crucible experiences are catalysts for personal growth and can be incorporated into game-based learning design whose intent is to create defining moments in which learners can explore emotional intelligence and examine who they are under challenging conditions. © 2011, IGI Global.

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TYPE Journal Article YEAR 2011
OSTIScopus
Results 68201–68400 of 96,771
Results 68201–68400 of 96,771