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Sample records for mechanics continuum modeling

  1. SEACAS Theory Manuals: Part II. Nonlinear Continuum Mechanics

    SciTech Connect (OSTI)

    Attaway, S.W.; Laursen, T.A.; Zadoks, R.I.

    1998-09-01

    This report summarizes the key continuum mechanics concepts required for the systematic prescription and numerical solution of finite deformation solid mechanics problems. Topics surveyed include measures of deformation appropriate for media undergoing large deformations, stress measures appropriate for such problems, balance laws and their role in nonlinear continuum mechanics, the role of frame indifference in description of large deformation response, and the extension of these theories to encompass two dimensional idealizations, structural idealizations, and rigid body behavior. There are three companion reports that describe the problem formulation, constitutive modeling, and finite element technology for nonlinear continuum mechanics systems.

  2. Continuum modeling of diffusion and dispersion in dense granular flows

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Continuum modeling of diffusion and dispersion in dense granular flows Citation Details In-Document Search Title: Continuum modeling of diffusion and dispersion in dense granular flows Authors: Christov, Ivan C [1] ; Stone, Howard A [2] + Show Author Affiliations Los Alamos National Laboratory [Los Alamos National Laboratory Mechanical & Aerospace Engineering, Princeton University [Mechanical & Aerospace Engineering, Princeton University Publication

  3. Equivalent Continuum Modeling for Shock Wave Propagation in Jointed...

    Office of Scientific and Technical Information (OSTI)

    Equivalent Continuum Modeling for Shock Wave Propagation in Jointed Media Citation Details In-Document Search Title: Equivalent Continuum Modeling for Shock Wave Propagation in...

  4. Continuum modeling of diffusion and dispersion in dense granular...

    Office of Scientific and Technical Information (OSTI)

    Continuum modeling of diffusion and dispersion in dense granular flows Citation Details In-Document Search Title: Continuum modeling of diffusion and dispersion in dense granular...

  5. Coupling Local to Nonlocal Continuum Models

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Local to Nonlocal Continuum Models - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management

  6. THMC Modeling of EGS Reservoirs … Continuum through Discontinuum...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Evolution and Induced Seismicity THMC Modeling of EGS Reservoirs Continuum through Discontinuum Representations: Capturing Reservoir Stimulation, Evolution and ...

  7. THMC Modeling of EGS Reservoirs … Continuum through Discontinuum

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Representations: Capturing Reservoir Stimulation, Evolution and Induced Seismicity | Department of Energy THMC Modeling of EGS Reservoirs … Continuum through Discontinuum Representations: Capturing Reservoir Stimulation, Evolution and Induced Seismicity THMC Modeling of EGS Reservoirs … Continuum through Discontinuum Representations: Capturing Reservoir Stimulation, Evolution and Induced Seismicity THMC Modeling of EGS Reservoirs … Continuum through Discontinuum Representations: Capturing

  8. Atomistic to continuum modeling of solidification microstructures

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Karma, Alain; Tourret, Damien

    2015-09-26

    We summarize recent advances in modeling of solidification microstructures using computational methods that bridge atomistic to continuum scales. We first discuss progress in atomistic modeling of equilibrium and non-equilibrium solid–liquid interface properties influencing microstructure formation, as well as interface coalescence phenomena influencing the late stages of solidification. The latter is relevant in the context of hot tearing reviewed in the article by M. Rappaz in this issue. We then discuss progress to model microstructures on a continuum scale using phase-field methods. We focus on selected examples in which modeling of 3D cellular and dendritic microstructures has been directly linked tomore » experimental observations. Finally, we discuss a recently introduced coarse-grained dendritic needle network approach to simulate the formation of well-developed dendritic microstructures. The approach reliably bridges the well-separated scales traditionally simulated by phase-field and grain structure models, hence opening new avenues for quantitative modeling of complex intra- and inter-grain dynamical interactions on a grain scale.« less

  9. Equivalent Continuum Modeling for Shock Wave Propagation in Jointed...

    Office of Scientific and Technical Information (OSTI)

    combined with the properties of the intact rock to develop an equivalent continuum model ... Two appraoches are suggested for modeling the rock mass. In one approach, jointed are ...

  10. Equivalent Continuum Modeling for Shock Wave Propagation in Jointed Media

    Office of Scientific and Technical Information (OSTI)

    (Technical Report) | SciTech Connect Equivalent Continuum Modeling for Shock Wave Propagation in Jointed Media Citation Details In-Document Search Title: Equivalent Continuum Modeling for Shock Wave Propagation in Jointed Media This study presents discrete and continuum simulations of shock wave propagating through jointed media. The simulations were performed using the Lagrangian hydrocode GEODYN-L with joints treated explicitly using an advanced contact algorithm. They studied both

  11. Comparison of Mesomechanical and Continuum Granular Flow Models for Ceramics

    SciTech Connect (OSTI)

    Curran, D. R.

    2006-07-28

    Constitutive models for the shear strength of ceramics undergoing fracture are needed for modeling long rod and shaped-charge jet penetration events in ceramic armor. The ceramic material ahead of the penetrator has been observed to be finely comminuted material that flows around the nose of the eroding penetrator (Shockey et al.). The most-used continuum models are of the Drucker-Prager type with an upper cutoff, or of the Mohr-Coulomb type with strain rate dependence and strain softening. A disadvantage of such models is that they have an unclear connection to the actual microscopic processes of granular flow and comminution. An alternate approach is to use mesomechanical models that describe the dynamics of the granular flow, as well as containing a description of the granular comminution and resultant material softening. However, a disadvantage of the mesomechanical models is that they are computationally more burdensome to apply. In the present paper, we compare the behaviors of a mesomechanical model, FRAGBED2, with the Walker and Johnson-Holmquist continuum models, where the granular material is subjected to simple strain histories under various confining pressures and strain rates. We conclude that the mesomechanical model can provide valuable input to the continuum models, both in interpretation of the continuum models' parameters and in suggesting their range of applicability.

  12. Relativistic Point Coupling Model for Vibrational Excitations in the Continuum

    SciTech Connect (OSTI)

    Ring, P.; Daoutidis, J.; Litvinova, E.; Niksic, T.; Paar, N.; Vretenar, D.

    2009-08-26

    An implementation of the relativistic random phase approximation with the proper treatment of the continuum has been developed for the relativistic point coupling model and applied to investigate collective excitations in spherical nuclei. The results are compared with the spectral implementation of the same model. In heavy nuclei, where the escape width is negligible, we find an excellent agreement between both methods in the region of giant resonance and some discrepancies in the region of low-lying pygmy resonance. The differences are more pronounced in light nuclei due to the larger values of the escape widths.

  13. Buckling of microtubules: An insight by molecular and continuum mechanics

    SciTech Connect (OSTI)

    Zhang, Jin; Meguid, S. A.

    2014-10-27

    The molecular structural mechanics method has been extended to investigate the buckling of microtubules (MTs) with various configurations. The results indicate that for relative short MTs the shear deformation effect, rather than the nonlocal effect, is mainly responsible for the limitation of their widely used Euler beam description and the observed length-dependence of their bending stiffness. In addition, the configuration effect of MTs is also studied and considered as an explanation for the large scattering of the critical buckling force and bending stiffness observed in existing experiments. This configuration effect is also found to mainly originate from the geometry of the MTs and is mainly determined by the protofilament number.

  14. Continuum model for chiral induced spin selectivity in helical molecules

    SciTech Connect (OSTI)

    Medina, Ernesto; Gonzlez-Arraga, Luis A.; Finkelstein-Shapiro, Daniel; Mujica, Vladimiro; Berche, Bertrand

    2015-05-21

    A minimal model is exactly solved for electron spin transport on a helix. Electron transport is assumed to be supported by well oriented p{sub z} type orbitals on base molecules forming a staircase of definite chirality. In a tight binding interpretation, the spin-orbit coupling (SOC) opens up an effective ?{sub z} ? ?{sub z} coupling via interbase p{sub x,y} ? p{sub z} hopping, introducing spin coupled transport. The resulting continuum model spectrum shows two Kramers doublet transport channels with a gap proportional to the SOC. Each doubly degenerate channel satisfies time reversal symmetry; nevertheless, a bias chooses a transport direction and thus selects for spin orientation. The model predicts (i) which spin orientation is selected depending on chirality and bias, (ii) changes in spin preference as a function of input Fermi level and (iii) back-scattering suppression protected by the SO gap. We compute the spin current with a definite helicity and find it to be proportional to the torsion of the chiral structure and the non-adiabatic Aharonov-Anandan phase. To describe room temperature transport, we assume that the total transmission is the result of a product of coherent steps.

  15. Organic carbon cycling in landfills: Model for a continuum approach

    SciTech Connect (OSTI)

    Bogner, J.; Lagerkvist, A.

    1997-09-01

    Organic carbon cycling in landfills can be addressed through a continuum model where the end-points are conventional anaerobic digestion of organic waste (short-term analogue) and geologic burial of organic material (long-term analogue). Major variables influencing status include moisture state, temperature, organic carbon loading, nutrient status, and isolation from the surrounding environment. Bioreactor landfills which are engineered for rapid decomposition approach (but cannot fully attain) the anaerobic digester end-point and incur higher unit costs because of their high degree of environmental isolation and control. At the other extreme, uncontrolled land disposal of organic waste materials is similar to geologic burial where organic carbon may be aerobically recycled to atmospheric CO{sub 2}, anaerobically converted to CH{sub 4} and CO{sub 2} during early diagenesis, or maintained as intermediate or recalcitrant forms into geologic time (> 1,000 years) for transformations via kerogen pathways. A family of improved landfill models are needed at several scales (molecular to landscape) which realistically address landfill processes and can be validated with field data.

  16. A continuum-scale model of hydrogen precipitate growth in tungsten plasma-facing materials.

    SciTech Connect (OSTI)

    Causey, Rion A.; Cowgill, Donald F.; Kolasinski, Robert D.

    2010-05-01

    The low solubility of hydrogen in tungsten leads to the growth of near-surface hydrogen precipitates during high-flux plasma exposure, strongly affecting migration and trapping in the material. We have developed a continuum-scale model of precipitate growth that leverages existing techniques for simulating the evolution of {sup 3}He gas bubbles in metal tritides. The present approach focuses on bubble growth by dislocation loop punching, assuming a diffusing flux to nucleation sites that arises from ion implantation. The bubble size is dictated by internal hydrogen pressure, the mechanical properties of the material, as well as local stresses. In this article, we investigate the conditions required for bubble growth. Recent focused ion beam (FIB) profiling studies that reveal the sub-surface damage structure provide an experimental database for comparison with the modeling results.

  17. Continuum modeling of diffusion and dispersion in dense granular...

    Office of Scientific and Technical Information (OSTI)

    + Show Author Affiliations Los Alamos National Laboratory Los Alamos National Laboratory Mechanical & Aerospace Engineering, Princeton University Mechanical & Aerospace...

  18. Progress toward bridging from atomistic to continuum modeling to predict nuclear waste glass dissolution.

    SciTech Connect (OSTI)

    Zapol, Peter; Bourg, Ian; Criscenti, Louise Jacqueline; Steefel, Carl I.; Schultz, Peter Andrew

    2011-10-01

    This report summarizes research performed for the Nuclear Energy Advanced Modeling and Simulation (NEAMS) Subcontinuum and Upscaling Task. The work conducted focused on developing a roadmap to include molecular scale, mechanistic information in continuum-scale models of nuclear waste glass dissolution. This information is derived from molecular-scale modeling efforts that are validated through comparison with experimental data. In addition to developing a master plan to incorporate a subcontinuum mechanistic understanding of glass dissolution into continuum models, methods were developed to generate constitutive dissolution rate expressions from quantum calculations, force field models were selected to generate multicomponent glass structures and gel layers, classical molecular modeling was used to study diffusion through nanopores analogous to those in the interfacial gel layer, and a micro-continuum model (K{mu}C) was developed to study coupled diffusion and reaction at the glass-gel-solution interface.

  19. High-order continuum kinetic method for modeling plasma dynamics in phase space

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Vogman, G. V.; Colella, P.; Shumlak, U.

    2014-12-15

    Continuum methods offer a high-fidelity means of simulating plasma kinetics. While computationally intensive, these methods are advantageous because they can be cast in conservation-law form, are not susceptible to noise, and can be implemented using high-order numerical methods. Advances in continuum method capabilities for modeling kinetic phenomena in plasmas require the development of validation tools in higher dimensional phase space and an ability to handle non-cartesian geometries. To that end, a new benchmark for validating Vlasov-Poisson simulations in 3D (x,vx,vy) is presented. The benchmark is based on the Dory-Guest-Harris instability and is successfully used to validate a continuum finite volumemore » algorithm. To address challenges associated with non-cartesian geometries, unique features of cylindrical phase space coordinates are described. Preliminary results of continuum kinetic simulations in 4D (r,z,vr,vz) phase space are presented.« less

  20. Continuum Modeling and Control of Large Nonuniform Wireless Networks via Nonlinear Partial Differential Equations

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Yang; Chong, Edwin K. P.; Hannig, Jan; Estep, Donald

    2013-01-01

    We inmore » troduce a continuum modeling method to approximate a class of large wireless networks by nonlinear partial differential equations (PDEs). This method is based on the convergence of a sequence of underlying Markov chains of the network indexed by N , the number of nodes in the network. As N goes to infinity, the sequence converges to a continuum limit, which is the solution of a certain nonlinear PDE. We first describe PDE models for networks with uniformly located nodes and then generalize to networks with nonuniformly located, and possibly mobile, nodes. Based on the PDE models, we develop a method to control the transmissions in nonuniform networks so that the continuum limit is invariant under perturbations in node locations. This enables the networks to maintain stable global characteristics in the presence of varying node locations.« less

  1. Sensitivity of the Properties of Ruthenium Blue Dimer to Method, Basis Set, and Continuum Model

    SciTech Connect (OSTI)

    Ozkanlar, Abdullah; Clark, Aurora E.

    2012-05-23

    The ruthenium blue dimer [(bpy)2RuIIIOH2]2O4+ is best known as the first well-defined molecular catalyst for water oxidation. It has been subject to numerous computational studies primarily employing density functional theory. However, those studies have been limited in the functionals, basis sets, and continuum models employed. The controversy in the calculated electronic structure and the reaction energetics of this catalyst highlights the necessity of benchmark calculations that explore the role of density functionals, basis sets, and continuum models upon the essential features of blue-dimer reactivity. In this paper, we report Kohn-Sham complete basis set (KS-CBS) limit extrapolations of the electronic structure of blue dimer using GGA (BPW91 and BP86), hybrid-GGA (B3LYP), and meta-GGA (M06-L) density functionals. The dependence of solvation free energy corrections on the different cavity types (UFF, UA0, UAHF, UAKS, Bondi, and Pauling) within polarizable and conductor-like polarizable continuum model has also been investigated. The most common basis sets of double-zeta quality are shown to yield results close to the KS-CBS limit; however, large variations are observed in the reaction energetics as a function of density functional and continuum cavity model employed.

  2. Quantifying sampling noise and parametric uncertainty in atomistic-to-continuum simulations using surrogate models

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Salloum, Maher N.; Sargsyan, Khachik; Jones, Reese E.; Najm, Habib N.; Debusschere, Bert

    2015-08-11

    We present a methodology to assess the predictive fidelity of multiscale simulations by incorporating uncertainty in the information exchanged between the components of an atomistic-to-continuum simulation. We account for both the uncertainty due to finite sampling in molecular dynamics (MD) simulations and the uncertainty in the physical parameters of the model. Using Bayesian inference, we represent the expensive atomistic component by a surrogate model that relates the long-term output of the atomistic simulation to its uncertain inputs. We then present algorithms to solve for the variables exchanged across the atomistic-continuum interface in terms of polynomial chaos expansions (PCEs). We alsomore » consider a simple Couette flow where velocities are exchanged between the atomistic and continuum components, while accounting for uncertainty in the atomistic model parameters and the continuum boundary conditions. Results show convergence of the coupling algorithm at a reasonable number of iterations. As a result, the uncertainty in the obtained variables significantly depends on the amount of data sampled from the MD simulations and on the width of the time averaging window used in the MD simulations.« less

  3. High-order continuum kinetic method for modeling plasma dynamics in phase space

    SciTech Connect (OSTI)

    Vogman, G. V.; Colella, P.; Shumlak, U.

    2014-12-15

    Continuum methods offer a high-fidelity means of simulating plasma kinetics. While computationally intensive, these methods are advantageous because they can be cast in conservation-law form, are not susceptible to noise, and can be implemented using high-order numerical methods. Advances in continuum method capabilities for modeling kinetic phenomena in plasmas require the development of validation tools in higher dimensional phase space and an ability to handle non-cartesian geometries. To that end, a new benchmark for validating Vlasov-Poisson simulations in 3D (x,vx,vy) is presented. The benchmark is based on the Dory-Guest-Harris instability and is successfully used to validate a continuum finite volume algorithm. To address challenges associated with non-cartesian geometries, unique features of cylindrical phase space coordinates are described. Preliminary results of continuum kinetic simulations in 4D (r,z,vr,vz) phase space are presented.

  4. Final Report for DOE Grant DE-FG02-03ER25579; Development of High-Order Accurate Interface Tracking Algorithms and Improved Constitutive Models for Problems in Continuum Mechanics with Applications to Jetting

    SciTech Connect (OSTI)

    Puckett, Elbridge Gerry; Miller, Gregory Hale

    2012-10-14

    Much of the work conducted under the auspices of DE-FG02-03ER25579 was characterized by an exceptionally close collaboration with researchers at the Lawrence Berkeley National Laboratory (LBNL). For example, Andy Nonaka, one of Professor Miller's graduate students in the Department of Applied Science at U. C. Davis (UCD) wrote his PhD thesis in an area of interest to researchers in the Applied Numerical Algorithms Group (ANAG), which is a part of the National Energy Research Supercomputer Center (NERSC) at LBNL. Dr. Nonaka collaborated closely with these researchers and subsequently published the results of this collaboration jointly with them, one article in a peer reviewed journal article and one paper in the proceedings of a conference. Dr. Nonaka is now a research scientist in the Center for Computational Sciences and Engineering (CCSE), which is also part of the National Energy Research Supercomputer Center (NERSC) at LBNL. This collaboration with researchers at LBNL also included having one of Professor Puckett's graduate students in the Graduate Group in Applied Mathematics (GGAM) at UCD, Sarah Williams, spend the summer working with Dr. Ann Almgren, who is a staff scientist in CCSE. As a result of this visit Sarah decided work on a problem suggested by the head of CCSE, Dr. John Bell, for her PhD thesis. Having finished all of the coursework and examinations required for a PhD, Sarah stayed at LBNL to work on her thesis under the guidance of Dr. Bell. Sarah finished her PhD thesis in June of 2007. Writing a PhD thesis while working at one of the University of California (UC) managed DOE laboratories is long established tradition at UC and Professor Puckett has always encouraged his students to consider doing this. Another one of Professor Puckett's graduate students in the GGAM at UCD, Christopher Algieri, was partially supported with funds from DE-FG02-03ER25579 while he wrote his MS thesis in which he analyzed and extended work originally published by Dr. Phillip Colella, the head of ANAG, and some of his colleagues. Chris Algieri is now employed as a staff member in Dr. Bill Collins' Climate Science Department in the Earth Sciences Division at LBNL working with computational models of climate change. Finally, it should be noted that the work conducted by Professor Puckett and his students Sarah Williams and Chris Algieri and described in this final report for DOE grant # DE-FC02-03ER25579 is closely related to work performed by Professor Puckett and his students under the auspices of Professor Puckett's DOE SciDAC grant DE-FC02-01ER25473 An Algorithmic and Software Framework for Applied Partial Differential Equations: A DOE SciDAC Integrated Software Infrastructure Center (ISIC). Dr. Colella was the lead PI for this SciDAC grant, which was comprised of several research groups from DOE national laboratories and five university PI's from five different universities. In theory Professor Puckett tried to use funds from the SciDAC grant to support work directly involved in implementing algorithms developed by members of his research group at UCD as software that might be of use to Puckett's SciDAC CoPIs. (For example, see the work reported in Section 2.2.2 of this final report.) However, since there is considerable lead time spent developing such algorithms before they are ready to become `software' and research plans and goals change as the research progresses, Professor Puckett supported each member of his research group partially with funds from the SciDAC APDEC ISIC DE-FC02-01ER25473 and partially with funds from this DOE MICS grant DE-FC02-03ER25579. This has necessarily resulted in a significant overlap of project areas that were funded by both grants. In particular, both Sarah Williams and Chris Algieri were supported partially with funds from grant # DE-FG02-03ER25579, for which this is the final report, and in part with funds from Professor Puckett's DOE SciDAC grant # DE-FC02-01ER25473. For example, Sarah Williams received support from DE-FC02- 01ER25473 and DE-FC02-03ER25579, both while at UCD taking cla

  5. Fluid Dynamics and Solid Mechanics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and Solid Mechanics Basic and applied research in theoretical continuum dynamics, modern hydrodynamic theory, materials modeling, global climate modeling, numerical...

  6. Continuum-kinetic-microscopic model of lung clearance due to core-annular fluid entrainment

    SciTech Connect (OSTI)

    Mitran, Sorin

    2013-07-01

    The human lung is protected against aspirated infectious and toxic agents by a thin liquid layer lining the interior of the airways. This airway surface liquid is a bilayer composed of a viscoelastic mucus layer supported by a fluid film known as the periciliary liquid. The viscoelastic behavior of the mucus layer is principally due to long-chain polymers known as mucins. The airway surface liquid is cleared from the lung by ciliary transport, surface tension gradients, and airflow shear forces. This work presents a multiscale model of the effect of airflow shear forces, as exerted by tidal breathing and cough, upon clearance. The composition of the mucus layer is complex and variable in time. To avoid the restrictions imposed by adopting a viscoelastic flow model of limited validity, a multiscale computational model is introduced in which the continuum-level properties of the airway surface liquid are determined by microscopic simulation of long-chain polymers. A bridge between microscopic and continuum levels is constructed through a kinetic-level probability density function describing polymer chain configurations. The overall multiscale framework is especially suited to biological problems due to the flexibility afforded in specifying microscopic constituents, and examining the effects of various constituents upon overall mucus transport at the continuum scale.

  7. STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS

    Office of Scientific and Technical Information (OSTI)

    (Technical Report) | SciTech Connect Technical Report: STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS Citation Details In-Document Search Title: STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS The research under this project focused on a theoretical and computational modeling of dislocation dynamics of mesoscale deformation of metal single crystals. Specifically, the work aimed to implement a continuum statistical theory of dislocations to understand

  8. STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS

    Office of Scientific and Technical Information (OSTI)

    (Technical Report) | SciTech Connect Technical Report: STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS Citation Details In-Document Search Title: STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS The research under this project focused on a theoretical and computational modeling of dislocation dynamics of mesoscale deformation of metal single crystals. Specifically, the work aimed to implement a continuum statistical theory of dislocations to understand

  9. On the ability of Order Statistics to distinguish different models for continuum gamma decay

    SciTech Connect (OSTI)

    Sandoval, J. J.; Cristancho, F.

    2007-10-26

    A simulation procedure to calculate some important parameters to the application of Order Statistics in the analysis of continuum gamma decay is presented.

  10. THMC Modeling of EGS Reservoirs -- Continuum through Discontinuum Representations. Capturing Reservoir Stimulation, Evolution and Induced Seismicity

    SciTech Connect (OSTI)

    Elsworth, Derek; Izadi, Ghazal; Gan, Quan; Fang, Yi; Taron, Josh; Sonnenthal, Eric

    2015-07-28

    This work has investigated the roles of effective stress induced by changes in fluid pressure, temperature and chemistry in contributing to the evolution of permeability and induced seismicity in geothermal reservoirs. This work has developed continuum models [1] to represent the progress or seismicity during both stimulation [2] and production [3]. These methods have been used to resolve anomalous observations of induced seismicity at the Newberry Volcano demonstration project [4] through the application of modeling and experimentation. Later work then focuses on the occurrence of late stage seismicity induced by thermal stresses [5] including the codifying of the timing and severity of such responses [6]. Furthermore, mechanistic linkages between observed seismicity and the evolution of permeability have been developed using data from the Newberry project [7] and benchmarked against field injection experiments. Finally, discontinuum models [8] incorporating the roles of discrete fracture networks have been applied to represent stimulation and then thermal recovery for new arrangements of geothermal wells incorporating the development of flow manifolds [9] in order to increase thermal output and longevity in EGS systems.

  11. Components for Atomistic-to-Continuum Multiscale Modeling of Flow in Micro- and Nanofluidic Systems

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Adalsteinsson, Helgi; Debusschere, Bert J.; Long, Kevin R.; Najm, Habib N.

    2008-01-01

    Micro- and nanofluidics pose a series of significant challenges for science-based modeling. Key among those are the wide separation of length- and timescales between interface phenomena and bulk flow and the spatially heterogeneous solution properties near solid-liquid interfaces. It is not uncommon for characteristic scales in these systems to span nine orders of magnitude from the atomic motions in particle dynamics up to evolution of mass transport at the macroscale level, making explicit particle models intractable for all but the simplest systems. Recently, atomistic-to-continuum (A2C) multiscale simulations have gained a lot of interest as an approach to rigorously handle particle-levelmore » dynamics while also tracking evolution of large-scale macroscale behavior. While these methods are clearly not applicable to all classes of simulations, they are finding traction in systems in which tight-binding, and physically important, dynamics at system interfaces have complex effects on the slower-evolving large-scale evolution of the surrounding medium. These conditions allow decomposition of the simulation into discrete domains, either spatially or temporally. In this paper, we describe how features of domain decomposed simulation systems can be harnessed to yield flexible and efficient software for multiscale simulations of electric field-driven micro- and nanofluidics.« less

  12. Unified continuum damage model for matrix cracking in composite rotor blades

    SciTech Connect (OSTI)

    Pollayi, Hemaraju; Harursampath, Dineshkumar

    2015-03-10

    This paper deals with modeling of the first damage mode, matrix micro-cracking, in helicopter rotor/wind turbine blades and how this effects the overall cross-sectional stiffness. The helicopter/wind turbine rotor system operates in a highly dynamic and unsteady environment leading to severe vibratory loads present in the system. Repeated exposure to this loading condition can induce damage in the composite rotor blades. These rotor/turbine blades are generally made of fiber-reinforced laminated composites and exhibit various competing modes of damage such as matrix micro-cracking, delamination, and fiber breakage. There is a need to study the behavior of the composite rotor system under various key damage modes in composite materials for developing Structural Health Monitoring (SHM) system. Each blade is modeled as a beam based on geometrically non-linear 3-D elasticity theory. Each blade thus splits into 2-D analyzes of cross-sections and non-linear 1-D analyzes along the beam reference curves. Two different tools are used here for complete 3-D analysis: VABS for 2-D cross-sectional analysis and GEBT for 1-D beam analysis. The physically-based failure models for matrix in compression and tension loading are used in the present work. Matrix cracking is detected using two failure criterion: Matrix Failure in Compression and Matrix Failure in Tension which are based on the recovered field. A strain variable is set which drives the damage variable for matrix cracking and this damage variable is used to estimate the reduced cross-sectional stiffness. The matrix micro-cracking is performed in two different approaches: (i) Element-wise, and (ii) Node-wise. The procedure presented in this paper is implemented in VABS as matrix micro-cracking modeling module. Three examples are presented to investigate the matrix failure model which illustrate the effect of matrix cracking on cross-sectional stiffness by varying the applied cyclic load.

  13. Mechanical effects in cookoff modeling

    SciTech Connect (OSTI)

    Gross, R.J.; Baer, M.R.; Hobbs, M.L.

    1994-07-01

    Complete cookoff modeling of energetic material in confined geometries must couple thermal, chemical and mechanical effects. In the past, modeling has focused on the prediction of the onset of combustion behavior based only on thermal-chemistry effects with little or no regard to the mechanical behavior of the energetic material. In this paper, an analysis tool is outlined which couples thermal, chemical, and mechanical behavior for one-dimensional Geometries comprised of multi-materials. A reactive heat flow code, XCHEM, and a quasistatic mechanics code, SANTOS, have been completely coupled using, a reactive, elastic-plastic constitutive model describing pressurization of the energetic material. This new Thermally Reactive Elastic-plastic explosive code, TREX, was developed to assess the coupling, of mechanics with thermal chemistry making multidimensional cookoff analysis possible. In this study, TREX is applied to confined and unconfined systems. The confined systems simulate One-Dimensional Time to explosion (ODTX) experiments in both spherical and cylindrical configurations. The spherical ODTX system is a 1.27 cm diameter sphere of TATB confined by aluminum exposed to a constant external temperature. The cylindrical ODTX system is an aluminum tube filled with HMX, NC, and inert exposed to a constant temperature bath. Finally. an unconfined system consisting of a hollow steel cylinder filled with a propellant composed of Al, RMX, and NC, representative of a rocket motor, is considered. This model system is subjected to transient internal and external radiative/convective boundary conditions representative of 5 minutes exposure to a fire. The confined systems show significant pressure prior to ignition, and the unconfined system shows extrusion of the propellent suggesting that the energetic material becomes more shock sensitive.

  14. Analysis of the {sup 6}He {beta} decay into the {alpha}+d continuum within a three-body model

    SciTech Connect (OSTI)

    Tursunov, E.M.; Baye, D.; Descouvemont, P.

    2006-01-15

    The {beta}-decay process of the {sup 6}He halo nucleus into the {alpha}+d continuum is studied in a three-body model. The {sup 6}He nucleus is described as an {alpha}+n+n system in hyperspherical coordinates on a Lagrange mesh. The convergence of the Gamow-Teller matrix element requires the knowledge of wave functions up to about 30 fm and of hypermomentum components up to K=24. The shape and absolute values of the transition probability per time and energy units of a recent experiment can be reproduced very well with an appropriate {alpha}+d potential. A total transition probability of 1.6x10{sup -6} s{sup -1} is obtained in agreement with that experiment. Halo effects are shown to be very important because of a strong cancellation between the internal and halo components of the matrix element, as observed in previous studies. The forbidden bound state in the {alpha}+d potential is found essential to reproduce the order of magnitude of the data. Comments are made on R-matrix fits.

  15. DENSE MULTIPHASE FLOW SIMULATION: CONTINUUM MODEL FOR POLY-DISPERSED SYSTEMS USING KINETIC THEORY

    SciTech Connect (OSTI)

    Moses Bogere

    2011-08-31

    The overall objective of the project was to verify the applicability of the FCMOM approach to the kinetic equations describing the particle flow dynamics. For monodispersed systems the fundamental equation governing the particle flow dynamics is the Boltzmann equation. During the project, the FCMOM was successfully applied to several homogeneous and in-homogeneous problems in different flow regimes, demonstrating that the FCMOM has the potential to be used to solve efficiently the Boltzmann equation. However, some relevant issues still need to be resolved, i.e. the homogeneous cooling problem (inelastic particles cases) and the transition between different regimes. In this report, the results obtained in homogeneous conditions are discussed first. Then a discussion of the validation results for in-homogeneous conditions is provided. And finally, a discussion will be provided about the transition between different regimes. Alongside the work on development of FCMOM approach studies were undertaken in order to provide insights into anisotropy or particles kinetics in riser hydrodynamics. This report includes results of studies of multiphase flow with unequal granular temperatures and analysis of momentum re-distribution in risers due to particle-particle and fluid-particle interactions. The study of multiphase flow with unequal granular temperatures entailed both simulation and experimental studies of two particles sizes in a riser and, a brief discussion of what was accomplished will be provided. And finally, a discussion of the analysis done on momentum re-distribution of gas-particles flow in risers will be provided. In particular a discussion of the remaining work needed in order to improve accuracy and predictability of riser hydrodynamics based on two-fluid models and how they can be used to model segregation in risers.

  16. Calculation of the Gibbs Free Energy of Solvation and Dissociation of HCl in Water via Monte Carlo Simulations and Continuum Solvation Models

    SciTech Connect (OSTI)

    McGrath, Matthew; Kuo, I-F W.; Ngouana, Brice F.; Ghogomu, Julius N.; Mundy, Christopher J.; Marenich, Aleksandr; Cramer, Christopher J.; Truhlar, Donald G.; Siepmann, Joern I.

    2013-08-28

    The free energy of solvation and dissociation of hydrogen chloride in water is calculated through a combined molecular simulation quantum chemical approach at four temperatures between T = 300 and 450 K. The free energy is first decomposed into the sum of two components: the Gibbs free energy of transfer of molecular HCl from the vapor to the aqueous liquid phase and the standard-state free energy of acid dissociation of HCl in aqueous solution. The former quantity is calculated using Gibbs ensemble Monte Carlo simulations using either Kohn-Sham density functional theory or a molecular mechanics force field to determine the system’s potential energy. The latter free energy contribution is computed using a continuum solvation model utilizing either experimental reference data or micro-solvated clusters. The predicted combined solvation and dissociation free energies agree very well with available experimental data. CJM was supported by the US Department of Energy,Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  17. MECHANICAL PROPERTY CHARACTERIZATIONS AND PERFORMANCE MODELING OF SOFC SEALS

    SciTech Connect (OSTI)

    Koeppel, Brian J.; Vetrano, John S.; Nguyen, Ba Nghiep; Sun, Xin; Khaleel, Mohammad A.

    2008-03-26

    This study provides modeling tools for the design of reliable seals for SOFC stacks. The work consists of 1) experimental testing to determine fundamental properties of SOFC sealing materials, and 2) numerical modeling of stacks and sealing systems. The material tests capture relevant temperature-dependent physical and mechanical data needed by the analytical models such as thermal expansion, strength, fracture toughness, and relaxation behavior for glass-ceramic seals and other materials. Testing has been performed on both homogenous specimens and multiple material assemblies to investigate the effect of interfacial reactions. A viscoelastic continuum damage model for a glass-ceramic seal was developed to capture the nonlinear behavior of this material at high temperatures. This model was implemented in the MSC MARC finite element code and was used for a detailed analysis of a planar SOFC stack under thermal cycling conditions. Realistic thermal loads for the stack were obtained using PNNLs in-house multiphysics solver. The accumulated seal damage and component stresses were evaluated for multiple thermal loading cycles, and regions of high seal damage susceptible to cracking were identified. Selected test results, numerical model development, and analysis results will be presented.

  18. The H2O2+OH ? HO2+H2O reaction in aqueous solution from a charge-dependent continuum model of solvation

    SciTech Connect (OSTI)

    Ginovska, Bojana; Camaioni, Donald M.; Dupuis, Michel

    2008-07-07

    We applied our recently developed protocol of the conductor-like continuum model of solvation to describe the title reaction in aqueous solution. The model has the unique feature of the molecular cavity being dependent on the atomic charges in the solute, and can be extended naturally to transition states and reaction pathways. It was used to calculate the reaction energetics and reaction rate in solution for the title reaction. The rate of reaction calculated using canonical variational transition state theory CVT in the context of the equilibrium solvation path (ESP) approximation, and including correction for tunneling through the small curvature approximation (SCT) was found to be 3.6 106 M-1 s-1, in very good agreement with experiment, These results suggest that the present protocol of the conductor-like continuum model of solvation with the charge-dependent cavity definition captures accurately the solvation effects at transition states and allows for quantitative estimates of reaction rates in solutions. This work was supported by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Chemical Sciences program. The Pacific Northwest National Laboratory is operated by Battelle for DOE.

  19. THMC Modeling of EGS Reservoirs …Continuum through Discontinuum Representations: Capturing Reservoir Stimulation, Evolution and Induced Seismicity

    Broader source: Energy.gov [DOE]

    This research will develop a thorough understanding of complex THMC interactions through synthesis, modeling and verification.

  20. Constraining UV continuum slopes of active galactic nuclei with cloudy models of broad-line region extreme-ultraviolet emission lines

    SciTech Connect (OSTI)

    Moloney, Joshua [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Michael Shull, J., E-mail: joshua.moloney@colorado.edu, E-mail: michael.shull@colorado.edu [Also at Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA, UK. (United Kingdom)

    2014-10-01

    Understanding the composition and structure of the broad-line region (BLR) of active galactic nuclei (AGNs) is important for answering many outstanding questions in supermassive black hole evolution, galaxy evolution, and ionization of the intergalactic medium. We used single-epoch UV spectra from the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope to measure EUV emission-line fluxes from four individual AGNs with 0.49 ? z ? 0.64, two AGNs with 0.32 ? z ? 0.40, and a composite of 159 AGNs. With the CLOUDY photoionization code, we calculated emission-line fluxes from BLR clouds with a range of density, hydrogen ionizing flux, and incident continuum spectral indices. The photoionization grids were fit to the observations using single-component and locally optimally emitting cloud (LOC) models. The LOC models provide good fits to the measured fluxes, while the single-component models do not. The UV spectral indices preferred by our LOC models are consistent with those measured from COS spectra. EUV emission lines such as N IV ?765, O II ?833, and O III ?834 originate primarily from gas with electron temperatures between 37,000 K and 55,000 K. This gas is found in BLR clouds with high hydrogen densities (n {sub H} ? 10{sup 12} cm{sup 3}) and hydrogen ionizing photon fluxes (?{sub H} ? 10{sup 22} cm{sup 2} s{sup 1}).

  1. Modeling the mechanical response of PBX 9501

    SciTech Connect (OSTI)

    Ragaswamy, Partha; Lewis, Matthew W; Liu, Cheng; Thompson, Darla G

    2010-01-01

    An engineering overview of the mechanical response of Plastic-Bonded eXplosives (PBXs), specifically PBX 9501, will be provided with emphasis on observed mechanisms associated with different types of mechanical testing. Mechanical tests in the form of uniaxial tension, compression, cyclic loading, creep (compression and tension), and Hopkinson bar show strain rate and temperature dependence. A range of mechanical behavior is observed which includes small strain recoverable response in the form of viscoelasticity; change in stiffness and softening beyond peak strength due to damage in the form microcracks, debonding, void formation and the growth of existing voids; inelastic response in the form of irrecoverable strain as shown in cyclic tests, and viscoelastic creep combined with plastic response as demonstrated in creep and recovery tests. The main focus of this paper is to elucidate the challenges and issues involved in modeling the mechanical behavior of PBXs for simulating thermo-mechanical responses in engineering components. Examples of validation of a constitutive material model based on a few of the observed mechanisms will be demonstrated against three point bending, split Hopkinson pressure bar and Brazilian disk geometry.

  2. Continuum damping of ideal toroidal Alfven eigenmodes

    SciTech Connect (OSTI)

    Zhang, X.D.; Zhang, Y.Z.; Mahajan, S.M. )

    1994-02-01

    A perturbation theory based on the two-dimensional (2-D) ballooning transform is systematically developed for ideal toroidal Alfven eigenmodes (TAEs). A formula, similar to the Fermi golden rule for decaying systems in quantum mechanics, is derived for the continuum damping rate of the TAE; the decay (damping) rate is expressed explicitly in terms of the coupling of the TAE to the continuum spectrum. Numerical results are compared with previous calculations. It is found that in some narrow intervals of the parameter [ital m][cflx [epsilon

  3. Modelling of volatility in monetary transmission mechanism

    SciTech Connect (OSTI)

    Dobešová, Anna; Klepáč, Václav; Kolman, Pavel; Bednářová, Petra

    2015-03-10

    The aim of this paper is to compare different approaches to modeling of volatility in monetary transmission mechanism. For this purpose we built time-varying parameter VAR (TVP-VAR) model with stochastic volatility and VAR-DCC-GARCH model with conditional variance. The data from three European countries are included in the analysis: the Czech Republic, Germany and Slovakia. Results show that VAR-DCC-GARCH system captures higher volatility of observed variables but main trends and detected breaks are generally identical in both approaches.

  4. Modeling-Thermo-electrochemistry, Capacity Degradation and Mechanics...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Modeling-Thermo-electrochemistry, Capacity Degradation and Mechanics with SEI Layer Modeling-Thermo-electrochemistry, Capacity Degradation and Mechanics with SEI Layer 2011 DOE ...

  5. Mechanical Modeling of a WIPP Drum Under Pressure | Department...

    Office of Environmental Management (EM)

    Mechanical Modeling of a WIPP Drum Under Pressure Mechanical Modeling of a WIPP Drum Under Pressure This document was used to determine facts and conditions during the Department...

  6. Thermal, chemical, and mechanical cookoff modeling

    SciTech Connect (OSTI)

    Hobbs, M.L.; Baer, M.R.; Gross, R.J.

    1994-08-01

    A Thermally Reactive, Elastic-plastic eXplosive code, TREX, has been developed to analyze coupled thermal, chemical and mechanical effects associated with cookoff simulation of confined or unconfined energetic materials. In confined systems, pressure buildup precedes thermal runaway, and unconfined energetic material expands to relieve high stress. The model was developed based on nucleation, decomposition chemistry, and elastic/plastic mechanical behavior of a material with a distribution of internal defects represented as clusters of spherical inclusions. A local force balance, with mass continuity constraints, forms the basis of the model requiring input of temperature and reacted gas fraction. This constitutive material model has been incorporated into a quasistatic mechanics code SANTOS as a material module which predicts stress history associated with a given strain history. The thermal-chemical solver XCHEM has been coupled to SANTOS to provide temperature and reacted gas fraction. Predicted spatial history variables include temperature, chemical species, solid/gas pressure, solid/gas density, local yield stress, and gas volume fraction. One-Dimensional Time to explosion (ODTX) experiments for TATB and PBX 9404 (HMX and NC) are simulated using global multistep kinetic mechanisms and the reactive elastic-plastic constitutive model. Pressure explosions, rather than thermal runaway, result in modeling slow cookoff experiments of confined conventional energetic materials such as TATB. For PBX 9404, pressure explosions also occur at fast cookoff conditions because of low temperature reactions of nitrocellulose resulting in substantial pressurization. A demonstrative calculation is also presented for reactive heat flow in a hollow, propellant-filled, stainless steel cylinder, representing a rocket motor. This example simulation show

  7. Prediction of Thermal Conductivity for Irradiated SiC/SiC Composites by Informing Continuum Models with Molecular Dynamics Data

    SciTech Connect (OSTI)

    Nguyen, Ba Nghiep; Gao, Fei; Henager, Charles H.; Kurtz, Richard J.

    2014-05-01

    This article proposes a new method to estimate the thermal conductivity of SiC/SiC composites subjected to neutron irradiation. The modeling method bridges different scales from the atomic scale to the scale of a 2D SiC/SiC composite. First, it studies the irradiation-induced point defects in perfect crystalline SiC using molecular dynamics (MD) simulations to compute the defect thermal resistance as a function of vacancy concentration and irradiation dose. The concept of defect thermal resistance is explored explicitly in the MD data using vacancy concentrations and thermal conductivity decrements due to phonon scattering. Point defect-induced swelling for chemical vapor deposited (CVD) SiC as a function of irradiation dose is approximated by scaling the corresponding MD results for perfect crystal ?-SiC to experimental data for CVD-SiC at various temperatures. The computed thermal defect resistance, thermal conductivity as a function of grain size, and definition of defect thermal resistance are used to compute the thermal conductivities of CVD-SiC, isothermal chemical vapor infiltrated (ICVI) SiC and nearly-stoichiometric SiC fibers. The computed fiber and ICVI-SiC matrix thermal conductivities are then used as input for an Eshelby-Mori-Tanaka approach to compute the thermal conductivities of 2D SiC/SiC composites subjected to neutron irradiation within the same irradiation doses. Predicted thermal conductivities for an irradiated Tyranno-SA/ICVI-SiC composite are found to be comparable to available experimental data for a similar composite ICVI-processed with these fibers.

  8. Predictors and mechanisms of the drought-influenced mortality of tree species along the isohydric to anisohydic continuum in a decade-long study of a central US temperate forest

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gu, L.; Pallardy, S. G.; Hosman, K. P.; Sun, Y.

    2015-01-19

    Using decade-long continuous observations of tree mortality and predawn leaf water potential (ψpd) at the Missouri Ozark AmeriFlux (MOFLUX) site, we studied how the mortality of important tree species varied along the isohydric to anisohydric continuum and how such variations may be predicted. Water stress determined inter-annual variations in tree mortality with a time delay of one year or more, which was predicted by predawn leaf water potential integral (PLWPI), mean effective precipitation interval (a time period with no daily precipitation rates exceeding a threshold) with a daily threshold precipitation at 5 mm day-1 (MEPI5), and precipitation variability index (PVI).more » Positive temperature anomaly integral (PTAI) and vapor pressure deficit integral (VPDI) also worked reasonably well, particularly for moderate droughts. The extreme drought of the year 2012 drastically increased the mortality of all species in the subsequent year. Regardless of the degree of isohydry and drought intensity, the ψpd of all species recovered rapidly after sufficiently intense rain events. This, together with a lack of immediate leaf and branch desiccation, suggests that hydraulic disconnection in the xylem was absent even during extreme drought and tree death was caused by significant but indirect effects of drought. We also found that species occupying middle positions along the isohydric to anisohydric continuum suffered less mortality than those at either extremes (i.e. extremely isohydric or extremely anisohydric). Finally, our study suggested that species differences in mortality mechanisms can be overwhelmed and masked in extreme droughts and should be examined in a broad range of drought intensity.« less

  9. Continuum Partners | Open Energy Information

    Open Energy Info (EERE)

    Partners Place: Denver, Colorado Zip: 80202 Sector: Solar Product: A Denver based real estate development company, also involved in Solar PV projects. References: Continuum...

  10. Failure Predictions for VHTR Core Components using a Probabilistic Contiuum Damage Mechanics Model

    SciTech Connect (OSTI)

    Fok, Alex

    2013-10-30

    The proposed work addresses the key research need for the development of constitutive models and overall failure models for graphite and high temperature structural materials, with the long-term goal being to maximize the design life of the Next Generation Nuclear Plant (NGNP). To this end, the capability of a Continuum Damage Mechanics (CDM) model, which has been used successfully for modeling fracture of virgin graphite, will be extended as a predictive and design tool for the core components of the very high- temperature reactor (VHTR). Specifically, irradiation and environmental effects pertinent to the VHTR will be incorporated into the model to allow fracture of graphite and ceramic components under in-reactor conditions to be modeled explicitly using the finite element method. The model uses a combined stress-based and fracture mechanics-based failure criterion, so it can simulate both the initiation and propagation of cracks. Modern imaging techniques, such as x-ray computed tomography and digital image correlation, will be used during material testing to help define the baseline material damage parameters. Monte Carlo analysis will be performed to address inherent variations in material properties, the aim being to reduce the arbitrariness and uncertainties associated with the current statistical approach. The results can potentially contribute to the current development of American Society of Mechanical Engineers (ASME) codes for the design and construction of VHTR core components.

  11. Mechanical Models of Fault-Related Folding

    SciTech Connect (OSTI)

    Johnson, A. M.

    2003-01-09

    The subject of the proposed research is fault-related folding and ground deformation. The results are relevant to oil-producing structures throughout the world, to understanding of damage that has been observed along and near earthquake ruptures, and to earthquake-producing structures in California and other tectonically-active areas. The objectives of the proposed research were to provide both a unified, mechanical infrastructure for studies of fault-related foldings and to present the results in computer programs that have graphical users interfaces (GUIs) so that structural geologists and geophysicists can model a wide variety of fault-related folds (FaRFs).

  12. STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS...

    Office of Scientific and Technical Information (OSTI)

    STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS Anter El-Azab 36 MATERIALS SCIENCE dislocation dynamics; mesoscale deformation of metals; crystal mechanics...

  13. Atom-to-continuum methods for gaining a fundamental understanding of fracture.

    SciTech Connect (OSTI)

    McDowell, David Lynn; Reedy, Earl David, Jr.; Templeton, Jeremy Alan; Jones, Reese E.; Moody, Neville Reid; Zimmerman, Jonathan A.; Belytschko, Ted.; Zhou, Xiao Wang; Lloyd, Jeffrey T.; Oswald, Jay; Delph, Terry J.; Kimmer, Christopher J.

    2011-08-01

    This report describes an Engineering Sciences Research Foundation (ESRF) project to characterize and understand fracture processes via molecular dynamics modeling and atom-to-continuum methods. Under this aegis we developed new theory and a number of novel techniques to describe the fracture process at the atomic scale. These developments ranged from a material-frame connection between molecular dynamics and continuum mechanics to an atomic level J integral. Each of the developments build upon each other and culminated in a cohesive zone model derived from atomic information and verified at the continuum scale. This report describes an Engineering Sciences Research Foundation (ESRF) project to characterize and understand fracture processes via molecular dynamics modeling and atom-to-continuum methods. The effort is predicated on the idea that processes and information at the atomic level are missing in engineering scale simulations of fracture, and, moreover, are necessary for these simulations to be predictive. In this project we developed considerable new theory and a number of novel techniques in order to describe the fracture process at the atomic scale. Chapter 2 gives a detailed account of the material-frame connection between molecular dynamics and continuum mechanics we constructed in order to best use atomic information from solid systems. With this framework, in Chapter 3, we were able to make a direct and elegant extension of the classical J down to simulations on the scale of nanometers with a discrete atomic lattice. The technique was applied to cracks and dislocations with equal success and displayed high fidelity with expectations from continuum theory. Then, as a prelude to extension of the atomic J to finite temperatures, we explored the quasi-harmonic models as efficient and accurate surrogates of atomic lattices undergoing thermo-elastic processes (Chapter 4). With this in hand, in Chapter 5 we provide evidence that, by using the appropriate energy potential, the atomic J integral we developed is calculable and accurate at finite/room temperatures. In Chapter 6, we return in part to the fundamental efforts to connect material behavior at the atomic scale to that of the continuum. In this chapter, we devise theory that predicts the onset of instability characteristic of fracture/failure via atomic simulation. In Chapters 7 and 8, we describe the culmination of the project in connecting atomic information to continuum modeling. In these chapters we show that cohesive zone models are: (a) derivable from molecular dynamics in a robust and systematic way, and (b) when used in the more efficient continuum-level finite element technique provide results that are comparable and well-correlated with the behavior at the atomic-scale. Moreover, we show that use of these same cohesive zone elements is feasible at scales very much larger than that of the lattice. Finally, in Chapter 9 we describe our work in developing the efficient non-reflecting boundary conditions necessary to perform transient fracture and shock simulation with molecular dynamics.

  14. Lagrangian continuum dynamics in ALEGRA.

    SciTech Connect (OSTI)

    Wong, Michael K. W.; Love, Edward

    2007-12-01

    Alegra is an ALE (Arbitrary Lagrangian-Eulerian) multi-material finite element code that emphasizes large deformations and strong shock physics. The Lagrangian continuum dynamics package in Alegra uses a Galerkin finite element spatial discretization and an explicit central-difference stepping method in time. The goal of this report is to describe in detail the characteristics of this algorithm, including the conservation and stability properties. The details provided should help both researchers and analysts understand the underlying theory and numerical implementation of the Alegra continuum hydrodynamics algorithm.

  15. Missing links in the root-soil organic matter continuum

    SciTech Connect (OSTI)

    O'Brien, Sarah L.; Iversen, Colleen M

    2009-01-01

    The soil environment remains one of the most complex and poorly understood research frontiers in ecology. Soil organic matter (SOM), which spans a continuum from fresh detritus to highly processed, mineral-associated organic matter, is the foundation of sustainable terrestrial ecosystems. Heterogeneous SOM pools are fueled by inputs from living and dead plants, driven by the activity of micro- and mesofauna, and are shaped by a multitude of abiotic factors. The specialization required to measure unseen processes that occur on a wide range of spatial and temporal scales has led to the partitioning of soil ecology research across several disciplines. In the organized oral session 'Missing links in the root-soil organic matter continuum' at the annual Ecological Society of America meeting in Albuquerque, NM, USA, we joined the call for greater communication and collaboration among ecologists who work at the root-soil interface (e.g. Coleman, 2008). Our goal was to bridge the gap between scientific disciplines and to synthesize disconnected pieces of knowledge from root-centric and soil-centric studies into an integrated understanding of belowground ecosystem processes. We focused this report around three compelling themes that arose from the session: (1) the influence of the rhizosphere on SOM cycling, (2) the role of soil heterotrophs in driving the transformation of root detritus to SOM, and (3) the controlling influence of the soil environment on SOM dynamics. We conclude with a discussion of new approaches for gathering data to bridge gaps in the root-SOM continuum and to inform the next generation of ecosystem models. Although leaf litter has often been considered to be the main source of organic inputs to soil, Ann Russell synthesized a convincing body of work demonstrating that roots, rather than surface residues, control the accumulation of SOM in a variety of ecosystems. Living roots, which are chemically diverse and highly dynamic, also influence a wide range of soil processes, from the exudation of labile C compounds to the development of fungal associations. For example, Zoe Cardon demonstrated that the root-mediated redistribution of deep soil water to relatively dry shallower soil, increased soil CO{sub 2} efflux and nutrient cycling near the surface in an arid ecosystem. Andrew Kulmatiski also discussed the importance of rooting distribution throughout the soil profile for strategies of water uptake by different species in an African savanna. Later, Julie Jastrow demonstrated that living roots shape soil physical structure by promoting the formation of soil aggregates, which facilitated accrual of SOM in restored grasslands. Taken together, the evidence is compelling that living roots, and organic matter derived from root detritus, are important parts of the continuum of organic matter in the soil. Larger soil organisms (i.e. 50 {micro}m to many cm in body size) play an important role in the root-SOM continuum by grazing on roots and microbes, comminuting organic matter and aggregating soil in fecal pellets. However, litterbag and soil incubation studies necessarily exclude invertebrates, and research on faunal activity and trophic dynamics tends to be independent from research on the biogeochemistry of SOM cycling. Tim Filley used plant-derived biomarkers in invertebrate residues to bridge the gap between larger soil organisms, such as earthworms and beetle larvae, and SOM distribution. He found that larger soil organisms help to stabilize root-derived organic matter in soil aggregates. Similar coupling of biogeochemistry with food web studies could prove fruitful for describing mechanisms that underlie critical ecosystem processes. Despite considerable research efforts, the breadth of the microbial role in the root-SOM continuum remains unresolved. Using advanced pyrosequencing techniques, David Nelson demonstrated the importance of archea as nitrifiers in agricultural systems exposed to elevated [CO{sub 2}]. Rising atmospheric [CO{sub 2}] and other changing environmental factors add a layer of complexity t

  16. Coupled Thermal-Hydrological-Mechanical-Chemical Model And Experiments...

    Broader source: Energy.gov (indexed) [DOE]

    Documents & Publications track 4: enhanced geothermal systems (EGS) | geothermal 2015 peer review Coupled Thermal-Hydrological-Mechanical-Chemical Model and Experiments for...

  17. Micro-mechanical modeling of perforating shock damage

    SciTech Connect (OSTI)

    Swift, R.P.; Krogh, K.E.; Behrmann, L.A.; Halleck, P.M.

    1997-11-17

    Shaped charge jet induced formation damage from perforation treatments hinders productivity. Manifestation of this damage is in the form of grain fragmentation resulting in fines that plug up pore throats along with the breakdown of inter-grain cementation. The authors use the Smooth Particle Hydrodynamic (SPH) computational method as a way to explicitly model, on a grain pore scale, the dynamic interactions of grains and grain/pores to calculate the damage resulting from perforation type stress wave loading. The SPH method is a continuum Lagrangian, meshless approach that features particles. Clusters of particles are used for each grain to provide representation of a grain pore structure that is similar to x-ray synchrotron microtomography images. Numerous damage models are available to portray fracture and fragmentation. In this paper the authors present the results of well defined impact loading on a grain pore structure that illustrate how the heterogeneity affects stress wave behavior and damage evolution. The SPH approach easily accommodates the coupling of multi-materials. Calculations for multi-material conditions with the pore space treated as a void, fluid filled, and/or clay filled show diverse effects on the stress wave propagation behavior and damage. SPH comparisons made with observed damage from recovered impacted sandstone samples in gas gun experiments show qualitatively the influence of stress intensity. The modeling approach presented here offers a unique way in concert with experiments to define a better understanding of formation damage resulting from perforation completion treatments.

  18. Modeling thermal/chemical/mechanical response of energetic materials

    SciTech Connect (OSTI)

    Baer, M.R.; Hobbs, M.L.; Gross, R.J.

    1995-07-01

    An overview of modeling at Sandia National Laboratories is presented which describes coupled thermal, chemical and mechanical response of energetic materials. This modeling addresses cookoff scenarios for safety assessment studies in systems containing energetic materials. Foundation work is discussed which establishes a method for incorporating chemistry and mechanics into multidimensional analysis. Finite element analysis offers the capabilities to simultaneously resolve reactive heat transfer and structural mechanics in complex geometries. Nonlinear conduction heat transfer, with multiple step finite-rate chemistry, is resolved using a thermal finite element code. Rate equations are solved element-by-element using a modified matrix-free stiff solver This finite element software was developed for the simulation of systems requiring large numbers of finite elements. An iterative implicit scheme, based on the conjugate gradient method, is used and a hemi-cube algorithm is employed for the determination of view factors in surface-to-surface radiation transfer The critical link between the reactive heat transfer and mechanics is the introduction of an appropriate constitutive material model providing a stress-strain relationship for quasi-static mechanics analysis. This model is formally derived from bubble nucleation theory, and parameter variations of critical model parameters indicate that a small degree of decomposition leads to significant mechanical response. Coupled thermal/chemical/mechanical analysis is presented which simulates experiments designed to probe cookoff thermal-mechanical response of energetic materials.

  19. Coupled Thermal-Hydrological-Mechanical-Chemical Model And Experiments For

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Optimization Of Enhanced Geothermal System Development And Production: Evaluation of Stimulation at the Newberry Volcano EGS Demonstration Site | Department of Energy Coupled Thermal-Hydrological-Mechanical-Chemical Model And Experiments For Optimization Of Enhanced Geothermal System Development And Production: Evaluation of Stimulation at the Newberry Volcano EGS Demonstration Site Coupled Thermal-Hydrological-Mechanical-Chemical Model And Experiments For Optimization Of Enhanced Geothermal

  20. Coarse-grained Energy Modeling of Rollback/Recovery Mechanisms.

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Coarse-grained Energy Modeling of Rollback/Recovery Mechanisms. Citation Details In-Document Search Title: Coarse-grained Energy Modeling of Rollback/Recovery Mechanisms. Abstract not provided. Authors: Ferreira, Kurt Brian ; Ibtesham, Dewan ; DeBonis, David ; Arnold, Dorian Publication Date: 2014-03-01 OSTI Identifier: 1141158 Report Number(s): SAND2014-2159C 505371 DOE Contract Number: DE-AC04-94AL85000 Resource Type: Conference Resource Relation: Conference:

  1. Modeling the Mechanical Performance of Die Casting Dies

    SciTech Connect (OSTI)

    R. Allen Miller

    2004-02-27

    The following report covers work performed at Ohio State on modeling the mechanical performance of dies. The focus of the project was development and particularly verification of finite element techniques used to model and predict displacements and stresses in die casting dies. The work entails a major case study performed with and industrial partner on a production die and laboratory experiments performed at Ohio State.

  2. Hybrid discrete/continuum algorithms for stochastic reaction networks

    SciTech Connect (OSTI)

    Safta, Cosmin; Sargsyan, Khachik; Debusschere, Bert; Najm, Habib N.

    2014-10-22

    Direct solutions of the Chemical Master Equation (CME) governing Stochastic Reaction Networks (SRNs) are generally prohibitively expensive due to excessive numbers of possible discrete states in such systems. To enhance computational efficiency we develop a hybrid approach where the evolution of states with low molecule counts is treated with the discrete CME model while that of states with large molecule counts is modeled by the continuum Fokker-Planck equation. The Fokker-Planck equation is discretized using a 2nd order finite volume approach with appropriate treatment of flux components to avoid negative probability values. The numerical construction at the interface between the discrete and continuum regions implements the transfer of probability reaction by reaction according to the stoichiometry of the system. As a result, the performance of this novel hybrid approach is explored for a two-species circadian model with computational efficiency gains of about one order of magnitude.

  3. Hybrid discrete/continuum algorithms for stochastic reaction networks

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Safta, Cosmin; Sargsyan, Khachik; Debusschere, Bert; Najm, Habib N.

    2014-10-22

    Direct solutions of the Chemical Master Equation (CME) governing Stochastic Reaction Networks (SRNs) are generally prohibitively expensive due to excessive numbers of possible discrete states in such systems. To enhance computational efficiency we develop a hybrid approach where the evolution of states with low molecule counts is treated with the discrete CME model while that of states with large molecule counts is modeled by the continuum Fokker-Planck equation. The Fokker-Planck equation is discretized using a 2nd order finite volume approach with appropriate treatment of flux components to avoid negative probability values. The numerical construction at the interface between the discretemore » and continuum regions implements the transfer of probability reaction by reaction according to the stoichiometry of the system. As a result, the performance of this novel hybrid approach is explored for a two-species circadian model with computational efficiency gains of about one order of magnitude.« less

  4. Mechanical properties and modeling of seal-forming lithologies

    SciTech Connect (OSTI)

    Kronenberg, A.K.; Russell, J.E.; Carter, N.L.; Mazariegos, R.; Ibanez, W.

    1993-01-01

    Specific goals and accomplishments of this research include: (1) The evaluation of models of salt diaper ascent that involve either power law, dislocation creep as determined experimentally by Horseman et al. (1993) or linear, fluid-assisted creep as reported by Spiers et al. (1988, 1990, 1992). We have compared models assuming these two, experimentally evaluated flow laws and examined the predictions they make regarding diaper incubation periods, ascent velocities, deviatoric stresses and strain rates. (2) The evaluation of the effects of differential loading on the initiation an of salt structures. (3) Examination of the role of basement faults on the initiation and morphologic evolution of salt structures. (4) Evaluation of the mechanical properties of shale as a function of pressure and determination of the nature of its brittle-ductile transition. (5) Evaluation of the mechanical anisotropies of shales with varying concentrations, distributions and preferred orientations of clay. (6) The determination of temperature and ratedependencies of strength for a shale constitutive model that can be used in numerical models that depend on viscous formulations. (7) Determination of the mechanisms of deformation for argillaceous rocks over awide range of conditions. (8) Evaluation of the effects of H[sub 2]O within clay interlayers, as adsorbed surface layers.

  5. Hai Wang, Z. Hua, W. Lua, M.D. Thouless - Department of Mechanical Engineering, and Department of Materials

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hai Wang, Z. Hua, W. Lua, M.D. Thouless - Department of Mechanical Engineering, and Department of Materials Science and Engineering, University of Michigan One of the fundamental challenges of multi-scale modeling is the integration of atomistic-scale effects to continuum scale calculations. For example, the analysis of creep deformation requires continuum-level finite-element calculations to compute local stresses and temperatures which are then used in atomistic models to determine local atom

  6. Expectations for the hard x-ray continuum and gamma-ray line...

    Office of Scientific and Technical Information (OSTI)

    In support of these observational campaigns, we provide predictions for the hard X-ray continuum and gamma-line emissions for 15 Type Ia explosion models gleaned from the ...

  7. Quanta to the Continuum: Opportunities for Mesoscale Science...

    Office of Scientific and Technical Information (OSTI)

    Quanta to the Continuum: Opportunities for Mesoscale Science Citation Details In-Document Search Title: Quanta to the Continuum: Opportunities for Mesoscale Science No abstract...

  8. Mechanical Modeling of a WIPP Drum Under Pressure

    SciTech Connect (OSTI)

    Smith, Jeffrey A.

    2014-11-25

    Mechanical modeling was undertaken to support the Waste Isolation Pilot Plant (WIPP) technical assessment team (TAT) investigating the February 14th 2014 event where there was a radiological release at the WIPP. The initial goal of the modeling was to examine if a mechanical model could inform the team about the event. The intention was to have a model that could test scenarios with respect to the rate of pressurization. It was expected that the deformation and failure (inability of the drum to contain any pressure) would vary according to the pressurization rate. As the work progressed there was also interest in using the mechanical analysis of the drum to investigate what would happen if a drum pressurized when it was located under a standard waste package. Specifically, would the deformation be detectable from camera views within the room. A finite element model of a WIPP 55-gallon drum was developed that used all hex elements. Analyses were conducted using the explicit transient dynamics module of Sierra/SM to explore potential pressurization scenarios of the drum. Theses analysis show similar deformation patterns to documented pressurization tests of drums in the literature. The calculated failure pressures from previous tests documented in the literature vary from as little as 16 psi to 320 psi. In addition, previous testing documented in the literature shows drums bulging but not failing at pressures ranging from 69 to 138 psi. The analyses performed for this study found the drums failing at pressures ranging from 35 psi to 75 psi. When the drums are pressurized quickly (in 0.01 seconds) there is significant deformation to the lid. At lower pressurization rates the deformation of the lid is considerably less, yet the lids will still open from the pressure. The analyses demonstrate the influence of pressurization rate on deformation and opening pressure of the drums. Analyses conducted with a substantial mass on top of the closed drum demonstrate that the drums will still open provided the pressure is high enough. Investigation teams should look for displaced drum lids when searching for drums that have pressurized and failed. The mechanical modeling study for this program is summarized in the following memo. Following a brief introduction, there is a summary of a brief literature review of previous pressure testing of drums, an explanation of the model, presentation of the key results, some discussion, and concluding with a summary and key points.

  9. Coupling Mechanical with Electrochemical-Thermal Models for Batteries under Abuse

    SciTech Connect (OSTI)

    Wierzbicki, Tomasz; Sahraei, Elham; Dajka, Stephen; Li, Genong; Santhanagopalan, Shriram; Zhang, Chao; Kim, Gi-Heon; Sprague, Michael A.

    2015-06-09

    This presentation provides an update on coupled mechanical-electrochemical-thermal models for batteries under abuse.

  10. A Hydro-mechanical Model and Analytical Solutions for Geomechanical Modeling of Carbon Dioxide Geological Sequestration

    SciTech Connect (OSTI)

    Xu, Zhijie; Fang, Yilin; Scheibe, Timothy D.; Bonneville, Alain

    2012-05-15

    We present a hydro-mechanical model for geological sequestration of carbon dioxide. The model considers the poroelastic effects by taking into account the coupling between the geomechanical response and the fluid flow in greater detail. The simplified hydro-mechanical model includes the geomechanical part that relies on the linear elasticity, while the fluid flow is based on the Darcys law. Two parts were coupled using the standard linear poroelasticity. Analytical solutions for pressure field were obtained for a typical geological sequestration scenario. The model predicts the temporal and spatial variation of pressure field and effects of permeability and elastic modulus of formation on the fluid pressure distribution.

  11. Model the Deformation and Failure of Solids

    Energy Science and Technology Software Center (OSTI)

    2001-10-19

    EMU models the deformation and failure of solids based on a reformulated theory of continuum mechanics known as the Peridynamic model. This approach allows dynamic fracture and other failure mechanisms to be simulated with a minimum of mesh effeces and without a need for supplementary kinetic relations for crack growth. Penetration by a rigid projectile is also included in the code.

  12. Comprehensive mechanisms for combustion chemistry: Experiment, modeling, and sensitivity analysis

    SciTech Connect (OSTI)

    Dryer, F.L.; Yetter, R.A.

    1993-12-01

    This research program is an integrated experimental/numerical effort to study pyrolysis and oxidation reactions and mechanisms for small-molecule hydrocarbon structures under conditions representative of combustion environments. The experimental aspects of the work are conducted in large diameter flow reactors, at pressures from one to twenty atmospheres, temperatures from 550 K to 1200 K, and with observed reaction times from 10{sup {minus}2} to 5 seconds. Gas sampling of stable reactant, intermediate, and product species concentrations provides not only substantial definition of the phenomenology of reaction mechanisms, but a significantly constrained set of kinetic information with negligible diffusive coupling. Analytical techniques used for detecting hydrocarbons and carbon oxides include gas chromatography (GC), and gas infrared (NDIR) and FTIR methods are utilized for continuous on-line sample detection of light absorption measurements of OH have also been performed in an atmospheric pressure flow reactor (APFR), and a variable pressure flow (VPFR) reactor is presently being instrumented to perform optical measurements of radicals and highly reactive molecular intermediates. The numerical aspects of the work utilize zero and one-dimensional pre-mixed, detailed kinetic studies, including path, elemental gradient sensitivity, and feature sensitivity analyses. The program emphasizes the use of hierarchical mechanistic construction to understand and develop detailed kinetic mechanisms. Numerical studies are utilized for guiding experimental parameter selections, for interpreting observations, for extending the predictive range of mechanism constructs, and to study the effects of diffusive transport coupling on reaction behavior in flames. Modeling using well defined and validated mechanisms for the CO/H{sub 2}/oxidant systems.

  13. The von Neumann model of measurement in quantum mechanics

    SciTech Connect (OSTI)

    Mello, Pier A.

    2014-01-08

    We describe how to obtain information on a quantum-mechanical system by coupling it to a probe and detecting some property of the latter, using a model introduced by von Neumann, which describes the interaction of the system proper with the probe in a dynamical way. We first discuss single measurements, where the system proper is coupled to one probe with arbitrary coupling strength. The goal is to obtain information on the system detecting the probe position. We find the reduced density operator of the system, and show how Lders rule emerges as the limiting case of strong coupling. The von Neumann model is then generalized to two probes that interact successively with the system proper. Now we find information on the system by detecting the position-position and momentum-position correlations of the two probes. The so-called 'Wigner's formula' emerges in the strong-coupling limit, while 'Kirkwood's quasi-probability distribution' is found as the weak-coupling limit of the above formalism. We show that successive measurements can be used to develop a state-reconstruction scheme. Finally, we find a generalized transform of the state and the observables based on the notion of successive measurements.

  14. Continuum physics with quenched overlap fermions

    SciTech Connect (OSTI)

    Duerr, Stephan; Hoelbling, Christian

    2005-10-01

    We calculate m{sub ud}=(m{sub u}+m{sub d})/2, m{sub s}, f{sub {pi}} and f{sub K} in the quenched continuum limit with UV-filtered overlap fermions. We see rather small scaling violations on lattices as coarse as a{sup -1}{approx_equal}1 GeV and conjecture that similar advantages would be manifest in unquenched studies.

  15. A Mechanical Fluid-Dynamical Model For Ground Movements At Campi...

    Open Energy Info (EERE)

    Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Caldera Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A Mechanical...

  16. N = 4 supersymmetric mechanics: Harmonic superspace as a universal tool of model-building

    SciTech Connect (OSTI)

    Ivanov, E. A.

    2013-08-15

    We overview applications of the harmonic superspace approach in models of N = 4supersymmetric mechanics, with emphasis on some recent results.

  17. Simulation of neoclassical transport with the continuum gyrokinetic code COGENT

    SciTech Connect (OSTI)

    Dorf, M. A.; Cohen, R. H.; Dorr, M.; Rognlien, T.; Hittinger, J.; Compton, J.; Colella, P.; Martin, D.; McCorquodale, P.

    2013-01-15

    The development of the continuum gyrokinetic code COGENT for edge plasma simulations is reported. The present version of the code models a nonlinear axisymmetric 4D (R, v{sub Parallel-To }, {mu}) gyrokinetic equation coupled to the long-wavelength limit of the gyro-Poisson equation. Here, R is the particle gyrocenter coordinate in the poloidal plane, and v{sub Parallel-To} and {mu} are the guiding center velocity parallel to the magnetic field and the magnetic moment, respectively. The COGENT code utilizes a fourth-order finite-volume (conservative) discretization combined with arbitrary mapped multiblock grid technology (nearly field-aligned on blocks) to handle the complexity of tokamak divertor geometry with high accuracy. Topics presented are the implementation of increasingly detailed model collision operators, and the results of neoclassical transport simulations including the effects of a strong radial electric field characteristic of a tokamak pedestal under H-mode conditions.

  18. INTEGRATED MODELING AND FIELD STUDY OF POTENTIAL MECHANISMS FOR...

    Office of Scientific and Technical Information (OSTI)

    NORTHWEST GEYSERS EGS DEMONSTRATION PROJECT PHASE 1: PRE- STIMULATION COUPLED GEOMECHANICAL MODELING TO GUIDE STIMULATION AND MONITORING PLANS Jonny Rutqvist, Patrick F. Dobson,...

  19. INTEGRATED MODELING AND FIELD STUDY OF POTENTIAL MECHANISMS FOR...

    Office of Scientific and Technical Information (OSTI)

    steam reservoir, in agreement with the conclusions of Nielson and Moore (2000). ... in agreement with an injection stimulation model proposed by Nielson and Moore (2000). ...

  20. Implementation of an anisotropic mechanical model for shale in Geodyn

    SciTech Connect (OSTI)

    Attaia, A.; Vorobiev, O.; Walsh, S.

    2015-05-15

    The purpose of this report is to present the implementation of a shale model in the Geodyn code, based on published rock material models and properties that can help a petroleum engineer in his design of various strategies for oil/gas recovery from shale rock formation.

  1. From Quanta to the Continuum: Opportunities for Mesoscale Science...

    Office of Scientific and Technical Information (OSTI)

    Quanta to the Continuum: Opportunities for Mesoscale Science Crabtree, George Argonne National Lab. (ANL), Argonne, IL (United States); Sarrao, John Los Alamos National Lab....

  2. Quanta to the Continuum: Opportunities for Mesoscale Science...

    Office of Scientific and Technical Information (OSTI)

    Quanta to the Continuum: Opportunities for Mesoscale Science Sarrao, John L Los Alamos National Laboratory; Crabtree, George Argonne National Laboratory 36 MATERIALS SCIENCE;...

  3. Quanta to the Continuum: Opportunities for Mesoscale Science...

    Office of Scientific and Technical Information (OSTI)

    Continuum: Opportunities for Mesoscale Science No abstract prepared. Authors: Sarrao, John L 1 ; Crabtree, George 2 + Show Author Affiliations Los Alamos National Laboratory...

  4. Modeling Mechanical Behavior of a Prismatic Replaceable Reflector Block

    SciTech Connect (OSTI)

    Robert Bratton

    2009-04-01

    This report outlines the development of finite element models used to determine temperature and stresses in a prismatic core reflector block. This initial analysis determines an appropriate temperature distribution in a prismatic reflector from limiting conditions in the adjacent fuel block based on simplifying assumptions.

  5. Force transduction and lipid binding in MscL: A continuum-molecular approach

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Vanegas, Juan M.; Arroyo, Marino; Fotiadis, Dimitrios

    2014-12-01

    The bacterial mechanosensitive channel MscL, a small protein mainly activated by membrane tension, is a central model system to study the transduction of mechanical stimuli into chemical signals. Mutagenic studies suggest that MscL gating strongly depends on both intra-protein and interfacial lipid-protein interactions. However, there is a gap between this detailed chemical information and current mechanical models of MscL gating. Here, we investigate the MscL bilayer-protein interface through molecular dynamics simulations, and take a combined continuum-molecular approach to connect chemistry and mechanics. We quantify the effect of membrane tension on the forces acting on the surface of the channel, andmore » identify interactions that may be critical in the force transduction between the membrane and MscL. We find that the local stress distribution on the protein surface is largely asymmetric, particularly under tension, with the cytoplasmic side showing significantly larger and more localized forces, which pull the protein radially outward. The molecular interactions that mediate this behavior arise from hydrogen bonds between the electronegative oxygens in the lipid headgroup and a cluster of positively charged lysine residues on the amphipathic S1 domain and the C-terminal end of the second trans-membrane helix. We take advantage of this strong interaction (estimated to be 10–13 kT per lipid) to actuate the channel (by applying forces on protein-bound lipids) and explore its sensitivity to the pulling magnitude and direction. We conclude by highlighting the simple motif that confers MscL with strong anchoring to the bilayer, and its presence in various integral membrane proteins including the human mechanosensitive channel K2P1 and bovine rhodopsin.« less

  6. Thermal mechanical stress modeling of GCtM seals

    SciTech Connect (OSTI)

    Dai, Steve Xunhu; Chambers, Robert

    2015-09-01

    Finite-element thermal stress modeling at the glass-ceramic to metal (GCtM) interface was conducted assuming heterogeneous glass-ceramic microstructure. The glass-ceramics were treated as composites consisting of high expansion silica crystalline phases dispersed in a uniform residual glass. Interfacial stresses were examined for two types of glass-ceramics. One was designated as SL16 glass -ceramic, owing to its step-like thermal strain curve with an overall coefficient of thermal expansion (CTE) at 16 ppm/C. Clustered Cristobalite is the dominant silica phase in SL16 glass-ceramic. The other, designated as NL16 glass-ceramic, exhibited clusters of mixed Cristobalite and Quartz and showed a near-linear thermal strain curve with a same CTE value.

  7. Vibration Stabilization of a Mechanical Model of a X-Band Linear Collider Final Focus Magnet

    SciTech Connect (OSTI)

    Frisch, Josef; Chang, Allison; Decker, Valentin; Doyle, Eric; Eriksson, Leif; Hendrickson, Linda; Himel, Thomas; Markiewicz, Thomas; Partridge, Richard; Seryi, Andrei; /SLAC

    2006-09-28

    The small beam sizes at the interaction point of a X-band linear collider require mechanical stabilization of the final focus magnets at the nanometer level. While passive systems provide adequate performance at many potential sites, active mechanical stabilization is useful if the natural or cultural ground vibration is higher than expected. A mechanical model of a room temperature linear collider final focus magnet has been constructed and actively stabilized with an accelerometer based system.

  8. Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Electrodes | Department of Energy Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined Electrodes Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined Electrodes 2010 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. PDF icon es093_daniel_2010_p.pdf More Documents & Publications Intercalation Kinetics and Ion Mobility in Electrode Materials for Advanced Lithium Ion

  9. Training and Research on Probabilistic Hydro-Thermo-Mechanical Modeling of

    Office of Scientific and Technical Information (OSTI)

    Carbon Dioxide Geological Sequestration in Fractured Porous Rocks (Technical Report) | SciTech Connect Training and Research on Probabilistic Hydro-Thermo-Mechanical Modeling of Carbon Dioxide Geological Sequestration in Fractured Porous Rocks Citation Details In-Document Search Title: Training and Research on Probabilistic Hydro-Thermo-Mechanical Modeling of Carbon Dioxide Geological Sequestration in Fractured Porous Rocks Colorado School of Mines conducted research and training in the

  10. Determination of Electrochemical Performance and Thermo-Mechanical-Chemical Stability of SOFCs from Defect Modeling

    SciTech Connect (OSTI)

    Eric Wachsman; Keith L. Duncan

    2006-09-30

    This research was focused on two distinct but related issues. The first issue concerned using defect modeling to understand the relationship between point defect concentration and the electrochemical, thermo-chemical and mechano-chemical properties of typical solid oxide fuel cell (SOFC) materials. The second concerned developing relationships between the microstructural features of SOFC materials and their electrochemical performance. To understand the role point defects play in ceramics, a coherent analytical framework was used to develop expressions for the dependence of thermal expansion and elastic modulus on point defect concentration in ceramics. These models, collectively termed the continuum-level electrochemical model (CLEM), were validated through fits to experimental data from electrical conductivity, I-V characteristics, elastic modulus and thermo-chemical expansion experiments for (nominally pure) ceria, gadolinia-doped ceria (GDC) and yttria-stabilized zirconia (YSZ) with consistently good fits. The same values for the material constants were used in all of the fits, further validating our approach. As predicted by the continuum-level electrochemical model, the results reveal that the concentration of defects has a significant effect on the physical properties of ceramic materials and related devices. Specifically, for pure ceria and GDC, the elastic modulus decreased while the chemical expansion increased considerably in low partial pressures of oxygen. Conversely, the physical properties of YSZ remained insensitive to changes in oxygen partial pressure within the studied range. Again, the findings concurred exactly with the predictions of our analytical model. Indeed, further analysis of the results suggests that an increase in the point defect content weakens the attractive forces between atoms in fluorite-structured oxides. The reduction treatment effects on the flexural strength and the fracture toughness of pure ceria were also evaluated at room temperature. The results reveal that the flexural strength decreases significantly after heat treatment in very low oxygen partial pressure environments; however, in contrast, fracture toughness is increased by 30-40% when the oxygen partial pressure was decreased to 10{sup -20} to 10{sup -22} atm range. Fractographic studies show that microcracks developed at 800 oC upon hydrogen reduction are responsible for the decreased strength. To understand the role of microstructure on electrochemical performance, electrical impedance spectra from symmetric LSM/YSZ/LSM cells was de-convoluted to obtain the key electrochemical components of electrode performance, namely charge transfer resistance, surface diffusion of reactive species and bulk gas diffusion through the electrode pores. These properties were then related to microstructural features, such as triple-phase boundary length and tortuosity. From these experiments we found that the impedance due to oxygen adsorption obeys a power law with pore surface area, while the impedance due to charge transfer is found to obey a power-law with respect to triple phase boundary length. A model based on kinetic theory explaining the power-law relationships observed was then developed. Finally, during our EIS work on the symmetric LSM/YSZ/LSM cells a technique was developed to improve the quality of high-frequency impedance data and their subsequent de-convolution.

  11. From Quanta to the Continuum: Opportunities for Mesoscale Science

    Office of Scientific and Technical Information (OSTI)

    (Technical Report) | SciTech Connect SciTech Connect Search Results Technical Report: From Quanta to the Continuum: Opportunities for Mesoscale Science Citation Details In-Document Search Title: From Quanta to the Continuum: Opportunities for Mesoscale Science This report explores the opportunity and defines the research agenda for mesoscale science-discovering, understanding, and controlling interactions among disparate systems and phenomena to reach the full potential of materials

  12. NREL Leads Energy Systems Integration - Continuum Magazine | NREL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Issue 4 Continuum. Clean Energy Innovation at NREL NREL Leads Energy Systems Integration Continuum is the National Renewable Energy Laboratory's publication that showcases the laboratory's latest and most impactful clean energy innovations and the researchers and unique facilities that make it all happen. Dan Says From our director Dan says More than a Dream-a Renewable Electricity Future 01 More than a Dream-a Renewable Electricity Future With improved grid flexibility, storage, and

  13. Energy Saving Homes and Buildings - Continuum Magazine | NREL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spring 2014 / Issue 6 Continuum. Clean Energy Innovation at NREL Energy Saving Homes and Buildings Continuum is the National Renewable Energy Laboratory's publication that showcases the laboratory's latest and most impactful clean energy innovations and the researchers and unique facilities that make it all happen. Dan Says From our director Dan says NREL Provides a Foundation for Home Energy Performance 01 NREL Provides a Foundation for Home Energy Performance NREL-led guidelines effort enables

  14. Variational description of continuum states in terms of integral relations

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Variational description of continuum states in terms of integral relations Citation Details In-Document Search Title: Variational description of continuum states in terms of integral relations Two integral relations derived from the Kohn variational principle (KVP) are used for describing scattering states. In usual applications the KVP requires the explicit form of the asymptotic behavior of the scattering wave function. This is not the case when the

  15. Understanding Creep Mechanisms in Graphite with Experiments, Multiscale Simulations, and Modeling

    SciTech Connect (OSTI)

    Eapen, Jacob; Murty, Korukonda; Burchell, Timothy

    2014-06-02

    Disordering mechanisms in graphite have a long history with conflicting viewpoints. Using Raman and x-ray photon spectroscopy, electron microscopy, x-ray diffraction experiments and atomistic modeling and simulations, the current project has developed a fundamental understanding of early-to-late state radiation damage mechanisms in nuclear reactor grade graphite (NBG-18 and PCEA). We show that the topological defects in graphite play an important role under neutron and ion irradiation.

  16. Mechanism and Kinetic Modeling of Hydrogenation in The Organic Getter/Pd

    Office of Scientific and Technical Information (OSTI)

    Catalyst/Activated Carbon Systems (Journal Article) | SciTech Connect Mechanism and Kinetic Modeling of Hydrogenation in The Organic Getter/Pd Catalyst/Activated Carbon Systems Citation Details In-Document Search Title: Mechanism and Kinetic Modeling of Hydrogenation in The Organic Getter/Pd Catalyst/Activated Carbon Systems Authors: Dinh, L N ; Cairns, G A ; Strickland, R ; McLean II, W ; Maxwell, R S Publication Date: 2014-09-25 OSTI Identifier: 1182700 Report Number(s): LLNL-JRNL-662218

  17. NSR&D FY15 Final Report. Modeling Mechanical, Thermal, and Chemical Effects of Impact

    SciTech Connect (OSTI)

    Long, Christopher Curtis; Ma, Xia; Zhang, Duan Zhong

    2015-11-02

    The main goal of this project is to develop a computer model that explains and predicts coupled mechanical, thermal and chemical responses of HE under impact and friction insults. The modeling effort is based on the LANL-developed CartaBlanca code, which is implemented with the dual domain material point (DDMP) method to calculate complex and coupled thermal, chemical and mechanical effects among fluids, solids and the transitions between the states. In FY 15, we have implemented the TEPLA material model for metal and performed preliminary can penetration simulation and begun to link with experiment. Currently, we are working on implementing a shock to detonation transition (SDT) model (SURF) and JWL equation of state.

  18. Shell model nuclear matrix elements for competing mechanisms contributing to double beta decay

    SciTech Connect (OSTI)

    Horoi, Mihai

    2013-12-30

    Recent progress in the shell model approach to the nuclear matrix elements for the double beta decay process are presented. This includes nuclear matrix elements for competing mechanisms to neutrionless double beta decay, a comparison between closure and non-closure approximation for {sup 48}Ca, and an updated shell model analysis of nuclear matrix elements for the double beta decay of {sup 136}Xe.

  19. Adhesive joint and composites modeling in SIERRA.

    SciTech Connect (OSTI)

    Ohashi, Yuki; Brown, Arthur A.; Hammerand, Daniel Carl; Adolf, Douglas Brian; Chambers, Robert S.; Foulk, James W., III

    2005-11-01

    Polymers and fiber-reinforced polymer matrix composites play an important role in many Defense Program applications. Recently an advanced nonlinear viscoelastic model for polymers has been developed and incorporated into ADAGIO, Sandia's SIERRA-based quasi-static analysis code. Standard linear elastic shell and continuum models for fiber-reinforced polymer-matrix composites have also been added to ADAGIO. This report details the use of these models for advanced adhesive joint and composites simulations carried out as part of an Advanced Simulation and Computing Advanced Deployment (ASC AD) project. More specifically, the thermo-mechanical response of an adhesive joint when loaded during repeated thermal cycling is simulated, the response of some composite rings under internal pressurization is calculated, and the performance of a composite container subjected to internal pressurization, thermal loading, and distributed mechanical loading is determined. Finally, general comparisons between the continuum and shell element approaches for modeling composites using ADAGIO are given.

  20. A Reduced Order Model of Force Displacement Curves for the Failure of Mechanical Bolts in Tension.

    SciTech Connect (OSTI)

    Moore, Keegan J.; Brake, Matthew Robert

    2015-12-01

    Assembled mechanical systems often contain a large number of bolted connections. These bolted connections (joints) are integral aspects of the load path for structural dynamics, and, consequently, are paramount for calculating a structure's stiffness and energy dissipation prop- erties. However, analysts have not found the optimal method to model appropriately these bolted joints. The complexity of the screw geometry causes issues when generating a mesh of the model. This report will explore different approaches to model a screw-substrate connec- tion. Model parameters such as mesh continuity, node alignment, wedge angles, and thread to body element size ratios are examined. The results of this study will give analysts a better understanding of the influences of these parameters and will aide in finding the optimal method to model bolted connections.

  1. Sub-discretized surface model with application to contact mechanics in multi-body simulation

    SciTech Connect (OSTI)

    Johnson, S; Williams, J

    2008-02-28

    The mechanics of contact between rough and imperfectly spherical adhesive powder grains are often complicated by a variety of factors, including several which vary over sub-grain length scales. These include several traction factors that vary spatially over the surface of the individual grains, including high energy electron and acceptor sites (electrostatic), hydrophobic and hydrophilic sites (electrostatic and capillary), surface energy (general adhesion), geometry (van der Waals and mechanical), and elasto-plastic deformation (mechanical). For mechanical deformation and reaction, coupled motions, such as twisting with bending and sliding, as well as surface roughness add an asymmetry to the contact force which invalidates assumptions for popular models of contact, such as the Hertzian and its derivatives, for the non-adhesive case, and the JKR and DMT models for adhesive contacts. Though several contact laws have been offered to ameliorate these drawbacks, they are often constrained to particular loading paths (most often normal loading) and are relatively complicated for computational implementation. This paper offers a simple and general computational method for augmenting contact law predictions in multi-body simulations through characterization of the contact surfaces using a hierarchically-defined surface sub-discretization. For the case of adhesive contact between powder grains in low stress regimes, this technique can allow a variety of existing contact laws to be resolved across scales, allowing for moments and torques about the contact area as well as normal and tangential tractions to be resolved. This is especially useful for multi-body simulation applications where the modeler desires statistical distributions and calibration for parameters in contact laws commonly used for resolving near-surface contact mechanics. The approach is verified against analytical results for the case of rough, elastic spheres.

  2. Expectations for the hard x-ray continuum and gamma-ray line fluxes from the typE IA supernova SN 2014J in M82

    SciTech Connect (OSTI)

    The, Lih-Sin [Department of Physics and Astronomy, Clemson University, SC 29634 (United States); Burrows, Adam, E-mail: tlihsin@clemson.edu, E-mail: burrows@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2014-05-10

    The hard X-ray continuum and gamma-ray lines from a Type Ia supernova dominate its integrated photon emissions and can provide unique diagnostics of the mass of the ejecta, the {sup 56}Ni yield and spatial distribution, its kinetic energy and expansion speed, and the mechanism of explosion. Such signatures and their time behavior 'X-ray' the bulk debris field in direct fashion, and do not depend on the ofttimes problematic and elaborate UV, optical, and near-infrared spectroscopy and radiative transfer that have informed the study of these events for decades. However, to date no hard photons have ever been detected from a Type Ia supernova in explosion. With the advent of the supernova SN 2014J in M82, at a distance of ?3.5 Mpc, this situation may soon change. Both NuSTAR and INTEGRAL have the potential to detect SN 2014J, and, if spectra and light curves can be measured, would usefully constrain the various explosion models published during the last ?30 yr. In support of these observational campaigns, we provide predictions for the hard X-ray continuum and gamma-line emissions for 15 Type Ia explosion models gleaned from the literature. The model set, containing as it does deflagration, delayed detonation, merger detonation, pulsational delayed detonation, and sub-Chandrasekhar helium detonation models, collectively spans a wide range of properties, and hence signatures. We provide a brief discussion of various diagnostics (with examples), but importantly make the spectral and line results available electronically to aid in the interpretation of the anticipated data.

  3. Development of a coupled thermo-hydro-mechanical model in discontinuous media for carbon sequestration

    SciTech Connect (OSTI)

    Fang, Yilin; Nguyen, Ba Nghiep; Carroll, Kenneth C.; Xu, Zhijie; Yabusaki, Steven B.; Scheibe, Timothy D.; Bonneville, Alain

    2013-09-12

    Geomechanical alteration of porous media is generally ignored for most shallow subsurface applications, whereas CO2 injection, migration, and trapping in deep saline aquifers will be controlled by coupled multifluid flow, energy transfer, and geomechanical processes. The accurate assessment of the risks associated with potential leakage of injected CO2 and the design of effective injection systems requires that we represent these coupled processes within numerical simulators. The objectives of this study were to develop a coupled thermal-hydro-mechanical model into a single software, and to examine the coupling of thermal, hydrological, and geomechanical processes for simulation of CO2 injection into the subsurface for carbon sequestration. A numerical model is developed to couple nonisothermal multiphase hydrological and geomechanical processes for prediction of multiple interconnected processes for carbon sequestration in deep saline aquifers. The geomechanics model was based on Rigid Body-Spring Model (RBSM), one of the discrete methods to model discontinuous rock system. Poissons effect that was often ignored by RBSM was considered in the model. The simulation of large-scale and long-term coupled processes in carbon capture and storage projects requires large memory and computational performance. Global Array Toolkit was used to build the model to permit the high performance simulations of the coupled processes. The model was used to simulate a case study with several scenarios to demonstrate the impacts of considering coupled processes and Poissons effect for the prediction of CO2 sequestration.

  4. Anaerobic waste-activated sludge digestion - A bioconversion mechanism and kinetic model

    SciTech Connect (OSTI)

    Shimizu, Tatsuo; Kudo, Kenzo; Nasu, Yoshikazu )

    1993-05-01

    The anaerobic bioconversion of raw and mechanically lysed waste-activated sludge was kinetically investigated. The hydrolysis of the biopolymers, such as protein, which leaked out from the biological sludge with ultrasonic lysis, was a first-order reaction in anaerobic digestion and the rate constant was much higher than the decay rate constant of the raw waste activated sludge. An anaerobic digestion model that is capable of evaluating the effect of the mechanical sludge lysis on digestive performance was developed. The present model includes four major biological processes - the release of intracellular matter with sludge lysis; hydrolysis of biopolymers to volatile acids; the degradation of various volatile acids to acetate; and the conversion of acetate and hydrogen to methane. Each process was assumed to follow first-order kinetics. The model approximately simulated the overall process performance of the anaerobic digestion of waste-activated sludge. The model suggested that when the lysed waste-activated sludge was fed, the overall digestive performance remarkably increased in the two-phase system consisting of an acid forming process and a methanogenic process, which ensured the symbiotic growth of acetogenic and methanogenic bacteria.

  5. Viscoelastic Model for Lung Parenchyma for Multi-Scale Modeling of Respiratory System Phase I: Hypo-Elastic Model for CFD Implementation

    SciTech Connect (OSTI)

    Freed, Alan D.; Einstein, Daniel R.

    2011-04-14

    An isotropic constitutive model for the parenchyma of lung has been derived from the theory of hypo-elasticity. The intent is to use it to represent the mechanical response of this soft tissue in sophisticated, computational, fluid-dynamic models of the lung. This demands that the continuum model be accurate, yet simple and effcient. An objective algorithm for its numeric integration is provided. The response of the model is determined for several boundary-value problems whose experiments are used for material characterization. The effective elastic, bulk, and shear moduli, and Poissons ratio, as tangent functions, are also derived. The model is characterized against published experimental data for lung. A bridge between this continuum model and a dodecahedral model of alveolar geometry is investigated, with preliminary findings being reported.

  6. Statistical model selection for better prediction and discovering science mechanisms that affect reliability

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Anderson-Cook, Christine M.; Morzinski, Jerome; Blecker, Kenneth D.

    2015-08-19

    Understanding the impact of production, environmental exposure and age characteristics on the reliability of a population is frequently based on underlying science and empirical assessment. When there is incomplete science to prescribe which inputs should be included in a model of reliability to predict future trends, statistical model/variable selection techniques can be leveraged on a stockpile or population of units to improve reliability predictions as well as suggest new mechanisms affecting reliability to explore. We describe a five-step process for exploring relationships between available summaries of age, usage and environmental exposure and reliability. The process involves first identifying potential candidatemore » inputs, then second organizing data for the analysis. Third, a variety of models with different combinations of the inputs are estimated, and fourth, flexible metrics are used to compare them. As a result, plots of the predicted relationships are examined to distill leading model contenders into a prioritized list for subject matter experts to understand and compare. The complexity of the model, quality of prediction and cost of future data collection are all factors to be considered by the subject matter experts when selecting a final model.« less

  7. Statistical model selection for better prediction and discovering science mechanisms that affect reliability

    SciTech Connect (OSTI)

    Anderson-Cook, Christine M.; Morzinski, Jerome; Blecker, Kenneth D.

    2015-08-19

    Understanding the impact of production, environmental exposure and age characteristics on the reliability of a population is frequently based on underlying science and empirical assessment. When there is incomplete science to prescribe which inputs should be included in a model of reliability to predict future trends, statistical model/variable selection techniques can be leveraged on a stockpile or population of units to improve reliability predictions as well as suggest new mechanisms affecting reliability to explore. We describe a five-step process for exploring relationships between available summaries of age, usage and environmental exposure and reliability. The process involves first identifying potential candidate inputs, then second organizing data for the analysis. Third, a variety of models with different combinations of the inputs are estimated, and fourth, flexible metrics are used to compare them. As a result, plots of the predicted relationships are examined to distill leading model contenders into a prioritized list for subject matter experts to understand and compare. The complexity of the model, quality of prediction and cost of future data collection are all factors to be considered by the subject matter experts when selecting a final model.

  8. Illuminating the 130 GeV Gamma Line with Continuum Photons (Journal...

    Office of Scientific and Technical Information (OSTI)

    Illuminating the 130 GeV Gamma Line with Continuum Photons Citation Details In-Document Search Title: Illuminating the 130 GeV Gamma Line with Continuum Photons Authors: Cohen,...

  9. General N=2 supersymmetric quantum mechanical model: Supervariable approach to its off-shell nilpotent symmetries

    SciTech Connect (OSTI)

    Krishna, S.; Shukla, A.; Malik, R.P.

    2014-12-15

    Using the supersymmetric (SUSY) invariant restrictions on the (anti-)chiral supervariables, we derive the off-shell nilpotent symmetries of the general one (0+1)-dimensional N=2 SUSY quantum mechanical (QM) model which is considered on a (1, 2)-dimensional supermanifold (parametrized by a bosonic variable t and a pair of Grassmannian variables ? and ?-bar with ?{sup 2}=(?-bar){sup 2}=0,?(?-bar)+(?-bar)?=0). We provide the geometrical meanings to the two SUSY transformations of our present theory which are valid for any arbitrary type of superpotential. We express the conserved charges and Lagrangian of the theory in terms of the supervariables (that are obtained after the application of SUSY invariant restrictions) and provide the geometrical interpretation for the nilpotency property and SUSY invariance of the Lagrangian for the general N=2 SUSY quantum theory. We also comment on the mathematical interpretation of the above symmetry transformations. - Highlights: A novel method has been proposed for the derivation of N=2 SUSY transformations. General N=2 SUSY quantum mechanical (QM) model with a general superpotential, is considered. The above SUSY QM model is generalized onto a (1, 2)-dimensional supermanifold. SUSY invariant restrictions are imposed on the (anti-)chiral supervariables. Geometrical meaning of the nilpotency property is provided.

  10. From Quanta to the Continuum: Opportunities for Mesoscale Science

    Office of Scientific and Technical Information (OSTI)

    SEPTEMBER 2012 FROM QUANTA TO THE CONTINUUM: opportunities for MESOSCALE SCIENCE A REPORT FOR THE BASIC ENERGY SCIENCES ADVISORY COMMITTEE MESOSCALE SCIENCE SUBCOMMITTEE About the Department of Energy's Basic Energy Sciences Program Basic Energy Sciences (BES) supports fundamental research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels. This research provides the foundations for new energy technologies and supports DOE missions in

  11. NREL Leads Energy Systems Integration, Continuum Magazine: Issue 4 (Book)

    SciTech Connect (OSTI)

    Not Available

    2013-04-01

    Continuum Magazine showcases NREL's latest and most impactful clean energy innovations. This issue, 'NREL Leads Energy Systems Integration' explores the discipline of energy systems integration, in particular the role of the laboratory's new, one-of-a-kind Energy System Integration Facility. NREL scientists, engineers, and analysts deeply understand the fundamental science and technologies underpinning major energy producing and consuming systems, as well as the transmission infrastructure and communications and data networks required to integrate energy systems at all scales.

  12. Microstructure and Mechanical Properties of n-irradiated Fe-Cr Model Alloys

    SciTech Connect (OSTI)

    Matijasevic, Milena; Al Mazouzi, Abderrahim

    2008-07-01

    High chromium ( 9-12 wt %) ferritic/martensitic steels are candidate structural materials for future fusion reactors and other advanced systems such as accelerator driven systems (ADS). Their use for these applications requires a careful assessment of their mechanical stability under high energy neutron irradiation and in aggressive environments. In particular, the Cr concentration has been shown to be a key parameter to be optimized in order to guarantee the best corrosion and swelling resistance, together with the least embrittlement. In this work, the characterization of the neutron irradiated Fe-Cr model alloys with different Cr % with respect to microstructure and mechanical tests will be presented. The behavior of Fe-Cr alloys have been studied using tensile tests at different temperature range ( from -160 deg. C to 300 deg. C). Irradiation-induced microstructure changes have been studied by TEM for two different irradiation doses at 300 deg. C. The density and the size distribution of the defects induced have been determined. The tensile test results indicate that Cr content affects the hardening behavior of Fe-Cr binary alloys. Hardening mechanisms are discussed in terms of Orowan type of approach by correlating TEM data to the measured irradiation hardening. (authors)

  13. Resonance-continuum interference in the di-photon Higgs signal at the LHC

    SciTech Connect (OSTI)

    Dixon, Lance

    2003-02-25

    A low mass Standard Model Higgs boson should be visible at the Large Hadron Collider through its production via gluon-gluon fusion and its decay to two photons. We compute the interference of this resonant process, gg {yields} H {yields} {gamma}{gamma}, with the continuum QCD background, gg {yields} {gamma}{gamma} induced by quark loops. Helicity selection rules suppress the effect, which is dominantly due to the imaginary part of the two-loop gg {yields} {gamma}{gamma} scattering amplitude. The interference is destructive, but only of order 5% in the Standard Model, which is still below the 10-20% present accuracy of the total cross section prediction. We comment on the potential size of such effects in other Higgs models.

  14. Multiscale modeling of beryllium: quantum mechanics and laser-driven shock experiments using novel diagnostics.

    SciTech Connect (OSTI)

    Swift, D. C.; Paisley, Dennis L.; Kyrala, George A.; Hauer, Allan

    2002-01-01

    Ab initio quantum mechanics was used to construct a thermodynamically complete and rigorous equation of state for beryllium in the hexagonal and body-centred cubic structures, and to predict elastic constants as a function of compression. The equation of state agreed well with Hugoniot data and previously-published equations of state, but the temperatures were significantly different. The hexagonal/bcc phase boundary agreed reasonably well with published data, suggesting that the temperatures in our new equation of state were accurate. Shock waves were induced in single crystals and polycrystalline foils of beryllium, by direct illumination using the TRIDENT laser at Los Alamos. The velocity history at the surface of the sample was measured using a line-imaging VISAR, and transient X-ray diffraction (TXD) records were obtained with a plasma backlighter and X-ray streak cameras. The VISAR records exhibited elastic precursors, plastic waves, phase changes and spall. Dual TXD records were taken, in Bragg and Laue orientations. The Bragg lines moved in response to compression in the uniaxial direction. Because direct laser drive was used, the results had to be interpreted with the aid of radiation hydrodynamics simulations to predict the loading history for each laser pulse. In the experiments where there was evidence of polymorphism in the VISAR record, additional lines appeared in the Bragg and Laue records. The corresponding pressures were consistent with the phase boundary predicted by the quantum mechanical equation of state for beryllium. A model of the response of a single crystal of beryllium to shock loading is being developed using these new theoretical and experimental results. This model will be used in meso-scale studies of the response of the microstructure, allowing us to develop a more accurate representation of the behaviour of polycrystalline beryllium.

  15. The abelian confinement mechanism revisited: New aspects of the GeorgiGlashow model

    SciTech Connect (OSTI)

    Anber, Mohamed M.

    2014-02-15

    The confinement problem remains one of the most difficult problems in theoretical physics. An important step toward the solution of this problem is Polyakovs work on abelian confinement. The GeorgiGlashow model is a natural testing ground for this mechanism which has been surprising us by its richness and wide applicability. In this work, we shed light on two new aspects of this model in 2+1 D. First, we develop a many-body description of the effective degrees of freedom. Namely, we consider a non-relativistic gas of W-bosons in the background of monopoleinstanton plasma. Many-body treatment is a standard toolkit in condensed matter physics. However, we add a new twist by supplying the monopoleinstantons as external background field. Using this construction along with a mean-field approximation, we calculate the form of the potential between two electric probes as a function of their separation. This potential is expressed in terms of the Meijer-G function which interpolates between logarithmic and linear behavior at small and large distances, respectively. Second, we develop a systematic approach to integrate out the effect of the W-bosons at finite temperature in the range 0?Tmodel. Using a heat kernel expansion that takes into account the non-trivial thermal holonomy, we show that the partition function describes a three-dimensional two-component Coulomb gas. We repeat our analysis using the many-body description which yields the same result and provides a check on our formalism. At temperatures close to the deconfinement temperature, the gas becomes essentially two-dimensional recovering the partition function of the dual sine-Gordon model that was considered in a previous work. -- Highlights: We consider the problem of abelian confinement in the GeorgiGlashow model from a new perspective. We develop a many-body description of the degrees of freedom of this model in the background of monopoleinstanton plasma. We use the many-body formalism to find an analytic expression of the potential between two probes at zero temperature. We also use a systematic approach to integrate out the W-bosons starting from the full relativistic partition function. This results in a three-dimensional two-component Coulomb gas with long range and AharonovBohm phase interaction.

  16. Improvement of Stent Retriever Design and Efficacy of Mechanical Thrombectomy in a Flow Model

    SciTech Connect (OSTI)

    Wenger, Katharina; Nagl, Frank; Wagner, Marlies Berkefeld, Joachim

    2013-02-15

    In vitro experiments were performed to evaluate the efficacy of mechanical intracranial thrombectomy comparing the newly developed Aperio stent retriever and standard devices for stroke treatment. The Aperio (A), with an increased working length of 4 cm and a special cell design for capturing and withholding clots, was compared to three benchmark devices: the Solitaire retrievable stent (B), the Merci X6 (C), and the Merci L5 retriever (D). In a vascular glass model with pulsatile flow, reminiscent of the M1 segment of the middle cerebral artery, we repeatedly induced occlusion by generating thrombi via a modified Chandler loop system. The numbers of recanalization attempts, peripheral embolizations, and recanalizations at the site of occlusion were recorded during 10 retrieval experiments with each device. Eleven devices were able to remove the blood clots from the occluded branch. In 34 of 40 experiments, restoration of flow was obtained in 1-3 attempts. The main differences between the study devices were observed in terms of clot withholding and fragmentation during retrieval. Although there was only one fragmentation recorded for device A, disengagement of the whole clot or peripheral embolization of fragments occurred more frequently (5-7 times) with devices B, C, and D. In a vascular model, the design of device A was best at capturing and withholding thrombi during retrieval. Further study will be necessary to see whether this holds true in clinical applications.

  17. Nano-mechanics of Tunable Adhesion using Non Covalent Forces

    SciTech Connect (OSTI)

    Kenneth Liechti

    2012-09-08

    The objective of this program was to examine, via experiment and atomistic and continuum analysis, coordinated noncovalent bonding over a range of length scales with a view to obtaining modulated, patterned and reversible bonding at the molecular level. The first step in this project was to develop processes for depositing self-assembled monolayers (SAMs) bearing carboxylic acid and amine moieties on Si (111) surfaces and probe tips of an interfacial force microscope (IFM). This allowed the adhesive portion of the interactions between functionalized surfaces to be fully captured in the force-displacement response (force profiles) that are measured by the IFM. The interactionswere extracted in the form of traction-separation laws using combined molecular and continuum stress analyses. In this approach, the results of molecular dynamics analyses of SAMs subjected to simple stress states are used to inform continuum models of their stress-strain behavior. Continuum analyses of the IFM experiment were then conducted, which incorporate the stress-strain behavior of the SAMs and traction-separation relations that represent the interactions between the tip and functionalized Si surface. Agreement between predicted and measured force profiles was taken to imply that the traction-separation relations have been properly extracted. Scale up to larger contact areas was considered by forming Si/SAM/Si sandwiches and then separating them via fracture experiments. The mode 1 traction-separation relations have been extracted using fracture mechanics concepts under mode 1 and mixed-mode conditions. Interesting differences were noted between the three sets of traction-separation relations.

  18. Computational aspects of the continuum quaternionic wave functions for hydrogen

    SciTech Connect (OSTI)

    Morais, J.

    2014-10-15

    Over the past few years considerable attention has been given to the role played by the Hydrogen Continuum Wave Functions (HCWFs) in quantum theory. The HCWFs arise via the method of separation of variables for the time-independent Schrödinger equation in spherical coordinates. The HCWFs are composed of products of a radial part involving associated Laguerre polynomials multiplied by exponential factors and an angular part that is the spherical harmonics. In the present paper we introduce the continuum wave functions for hydrogen within quaternionic analysis ((R)QHCWFs), a result which is not available in the existing literature. In particular, the underlying functions are of three real variables and take on either values in the reduced and full quaternions (identified, respectively, with R{sup 3} and R{sup 4}). We prove that the (R)QHCWFs are orthonormal to one another. The representation of these functions in terms of the HCWFs are explicitly given, from which several recurrence formulae for fast computer implementations can be derived. A summary of fundamental properties and further computation of the hydrogen-like atom transforms of the (R)QHCWFs are also discussed. We address all the above and explore some basic facts of the arising quaternionic function theory. As an application, we provide the reader with plot simulations that demonstrate the effectiveness of our approach. (R)QHCWFs are new in the literature and have some consequences that are now under investigation.

  19. High strain-rate model for fiber-reinforced composites

    SciTech Connect (OSTI)

    Aidun, J.B.; Addessio, F.L.

    1995-07-01

    Numerical simulations of dynamic uniaxial strain loading of fiber-reinforced composites are presented that illustrate the wide range of deformation mechanisms that can be captured using a micromechanics-based homogenization technique as the material model in existing continuum mechanics computer programs. Enhancements to the material model incorporate high strain-rate plastic response, elastic nonlinearity, and rate-dependent strength degradation due to material damage, fiber debonding, and delamination. These make the model relevant to designing composite structural components for crash safety, armor, and munitions applications.

  20. On the use of Extreme Value Theory in analyses of continuum gamma decay

    SciTech Connect (OSTI)

    Garcia-Ruiz, R. F.; Cristancho, F.

    2010-08-04

    Extreme Value theory seems to be a promising tool for analysing experimental continuum gamma decay spectra in order to obtain physical parameters at high excitation energy.

  1. Sierra/solid mechanics 4.22 user's guide.

    SciTech Connect (OSTI)

    Thomas, Jesse David

    2011-10-01

    Sierra/SolidMechanics (Sierra/SM) is a Lagrangian, three-dimensional code for the analysis of solids and structures. It provides capabilities for explicit dynamic and implicit quasistatic and dynamic analyses. The explicit dynamics capabilities allow for the efficient and robust solution of models subjected to large, suddenly applied loads. For implicit problems, Sierra/SM uses a multi-level iterative solver, which enables it to effectively solve problems with large deformations, nonlinear material behavior, and contact. Sierra/SM has a versatile library of continuum and structural elements, and an extensive library of material models. The code is written for parallel computing environments, and it allows for scalable solutions of very large problems for both implicit and explicit analyses. It is built on the SIERRA Framework, which allows for coupling with other SIERRA mechanics codes. This document describes the functionality and input structure for Sierra/SM.

  2. Critical review: Radionuclide transport, sediment transport, and water quality mathematical modeling; and radionuclide adsorption/desorption mechanisms

    SciTech Connect (OSTI)

    Onishi, Y.; Serne, R.J.; Arnold, E.M.; Cowan, C.E.; Thompson, F.L.

    1981-01-01

    This report describes the results of a detailed literature review of radionuclide transport models applicable to rivers, estuaries, coastal waters, the Great Lakes, and impoundments. Some representatives sediment transport and water quality models were also reviewed to evaluate if they can be readily adapted to radionuclide transport modeling. The review showed that most available transport models were developed for dissolved radionuclide in rivers. These models include the mechanisms of advection, dispersion, and radionuclide decay. Since the models do not include sediment and radionuclide interactions, they are best suited for simulating short-term radionuclide migration where: (1) radionuclides have small distribution coefficients; (2) sediment concentrations in receiving water bodies are very low. Only 5 of the reviewed models include full sediment and radionuclide interactions: CHMSED developed by Fields; FETRA SERATRA, and TODAM developed by Onishi et al, and a model developed by Shull and Gloyna. The 5 models are applicable to cases where: (1) the distribution coefficient is large; (2) sediment concentrations are high; or (3) long-term migration and accumulation are under consideration. The report also discusses radionuclide absorption/desorption distribution ratios and addresses adsorption/desorption mechanisms and their controlling processes for 25 elements under surface water conditions. These elements are: Am, Sb, C, Ce, Cm, Co, Cr, Cs, Eu, I, Fe, Mn, Np, P, Pu, Pm, Ra, Ru, Sr, Tc, Th, {sup 3}H, U, Zn and Zr.

  3. Thermo-mechanical Modelling of Pebble Beds in Fusion Blankets and its Implementation by a Return-Mapping Algorithm

    SciTech Connect (OSTI)

    Gan, Yixiang; Kamlah, Marc

    2008-07-01

    In this investigation, a thermo-mechanical model of pebble beds is adopted and developed based on experiments by Dr. Reimann at Forschungszentrum Karlsruhe (FZK). The framework of the present material model is composed of a non-linear elastic law, the Drucker-Prager-Cap theory, and a modified creep law. Furthermore, the volumetric inelastic strain dependent thermal conductivity of beryllium pebble beds is taken into account and full thermo-mechanical coupling is considered. Investigation showed that the Drucker-Prager-Cap model implemented in ABAQUS can not fulfill the requirements of both the prediction of large creep strains and the hardening behaviour caused by creep, which are of importance with respect to the application of pebble beds in fusion blankets. Therefore, UMAT (user defined material's mechanical behaviour) and UMATHT (user defined material's thermal behaviour) routines are used to re-implement the present thermo-mechanical model in ABAQUS. An elastic predictor radial return mapping algorithm is used to solve the non-associated plasticity iteratively, and a proper tangent stiffness matrix is obtained for cost-efficiency in the calculation. An explicit creep mechanism is adopted for the prediction of time-dependent behaviour in order to represent large creep strains in high temperature. Finally, the thermo-mechanical interactions are implemented in a UMATHT routine for the coupled analysis. The oedometric compression tests and creep tests of pebble beds at different temperatures are simulated with the help of the present UMAT and UMATHT routines, and the comparison between the simulation and the experiments is made. (authors)

  4. A Mathematical Analysis of Atomistic-to-Continuum (AtC) Multiscale Coupling Methods

    SciTech Connect (OSTI)

    Gunzburger, Max

    2013-11-13

    We have worked on several projects aimed at improving the efficiency and understanding of multiscale methods, especially those applicable to problems involving atomistic-to-continuum coupling. Activities include blending methods for AtC coupling and efficient quasi-continuum methods for problems with long-range interactions.

  5. DUST CONTINUUM EMISSION AS A TRACER OF GAS MASS IN GALAXIES

    SciTech Connect (OSTI)

    Groves, Brent A.; Schinnerer, Eva; Walter, Fabian; Leroy, Adam; Galametz, Maud; Bolatto, Alberto; Hunt, Leslie; Dale, Daniel; Calzetti, Daniela; Croxall, Kevin; Kennicutt, Robert Jr.

    2015-01-20

    We use a sample of 36 galaxies from the KINGFISH (Herschel IR), HERACLES (IRAM CO), and THINGS (Very Large Array H I) surveys to study empirical relations between Herschel infrared (IR) luminosities and the total mass of the interstellar gas (H{sub 2} + H I). Such a comparison provides a simple empirical relationship without introducing the uncertainty of dust model fitting. We find tight correlations, and provide fits to these relations, between Herschel luminosities and the total gas mass integrated over entire galaxies, with the tightest, almost linear, correlation found for the longest wavelength data (SPIRE 500). However, we find that accounting for the gas-phase metallicity (affecting the dust to gas ratio) is crucial when applying these relations to low-mass, and presumably high-redshift, galaxies. The molecular (H{sub 2}) gas mass is found to be better correlated with the peak of the IR emission (e.g., PACS160), driven mostly by the correlation of stellar mass and mean dust temperature. When examining these relations as a function of galactocentric radius, we find the same correlations, albeit with a larger scatter, up to a radius of r ? 0.7 r {sub 25} (containing most of a galaxy's baryonic mass). However, beyond that radius, the same correlations no longer hold, with increasing gas (predominantly H I) mass relative to the infrared emission. The tight relations found for the bulk of the galaxy's baryonic content suggest that total gas masses of disk-like (non-merging/ULIRG) galaxies can be inferred from far-infrared continuum measurements in situations where only the latter are available, e.g., in ALMA continuum observations of high-redshift galaxies.

  6. CGILS: Results from the First Phase of an International Project to Understand the Physical Mechanisms of Low Cloud Feedbacks in Single Column Models

    SciTech Connect (OSTI)

    Zhang, Minghua; Bretherton, Christopher S.; Blossey, Peter; Austin, Phillip A.; Bacmeister, J.; Bony, Sandrine; Brient, Florent; Cheedela, Suvarchal K.; Cheng, Anning; Del Genio, Anthony D.; De Roode, Stephan R.; Endo , Satoshi; Franklin, Charmaine N.; Golaz, Jean-Christophe; Hannay, Cecile; Heus, Thijs; Isotta, Francesco A.; Jean-Louis, Dufresne; Kang, In-Sik; Kawai, Hideaki; Koehler, M.; Larson, Vincent E.; Liu, Yangang; Lock, Adrian; Lohmann, U.; Khairoutdinov, Marat; Molod, Andrea M.; Neggers, Roel; Rasch, Philip J.; Sandu, Irina; Senkbeil, Ryan; Siebesma, A. P.; Siegenthaler-Le Drian, Colombe; Stevens, Bjorn; Suarez, Max; Xu, Kuan-Man; Von Salzen, Knut; Webb, Mark; Wolf, Audrey; Zhao, M.

    2013-12-26

    Large Eddy Models (LES) and Single Column Models (SCM) are used in a surrogate climate change 101 to investigate the physical mechanism of low cloud feedbacks in climate models. Enhanced surface-102 driven boundary layer turbulence and shallow convection in a warmer climate are found to be 103 dominant mechanisms in SCMs.

  7. Meta-analysis of high-latitude nitrogen-addition and warming studies implies ecological mechanisms overlooked by land models

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bouskill, N. J.; Riley, W. J.; Tang, J. Y.

    2014-12-11

    Accurate representation of ecosystem processes in land models is crucial for reducing predictive uncertainty in energy and greenhouse gas feedbacks with the climate. Here we describe an observational and modeling meta-analysis approach to benchmark land models, and apply the method to the land model CLM4.5 with two versions of belowground biogeochemistry. We focused our analysis on the aboveground and belowground responses to warming and nitrogen addition in high-latitude ecosystems, and identified absent or poorly parameterized mechanisms in CLM4.5. While the two model versions predicted similar soil carbon stock trajectories following both warming and nitrogen addition, other predicted variables (e.g., belowgroundmore » respiration) differed from observations in both magnitude and direction, indicating that CLM4.5 has inadequate underlying mechanisms for representing high-latitude ecosystems. On the basis of observational synthesis, we attribute the model–observation differences to missing representations of microbial dynamics, aboveground and belowground coupling, and nutrient cycling, and we use the observational meta-analysis to discuss potential approaches to improving the current models. However, we also urge caution concerning the selection of data sets and experiments for meta-analysis. For example, the concentrations of nitrogen applied in the synthesized field experiments (average = 72 kg ha-1 yr-1) are many times higher than projected soil nitrogen concentrations (from nitrogen deposition and release during mineralization), which precludes a rigorous evaluation of the model responses to likely nitrogen perturbations. Overall, we demonstrate that elucidating ecological mechanisms via meta-analysis can identify deficiencies in ecosystem models and empirical experiments.« less

  8. Meta-analysis of high-latitude nitrogen-addition and warming studies imply ecological mechanisms overlooked by land models

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bouskill, N. J.; Riley, W. J.; Tang, J.

    2014-08-18

    Accurate representation of ecosystem processes in land models is crucial for reducing predictive uncertainty in energy and greenhouse gas feedbacks with the atmosphere. Here we describe an observational and modeling meta-analysis approach to benchmark land models, and apply the method to the land model CLM4.5 with two versions of belowground biogeochemistry. We focused our analysis on the above and belowground high-latitude ecosystem responses to warming and nitrogen addition, and identified mechanisms absent, or poorly parameterized in CLM4.5. While the two model versions predicted similar trajectories for soil carbon stocks following both types of perturbation, other variables (e.g., belowground respiration) differedmore » from the observations in both magnitude and direction, indicating the underlying mechanisms are inadequate for representing high-latitude ecosystems. The observational synthesis attribute these differences to missing representations of microbial dynamics, characterization of above and belowground functional processes, and nutrient competition. We use the observational meta-analyses to discuss potential approaches to improving the current models (e.g., the inclusion of dynamic vegetation or different microbial functional guilds), however, we also raise a cautionary note on the selection of data sets and experiments to be included in a meta-analysis. For example, the concentrations of nitrogen applied in the synthesized field experiments (average =72 kg ha-1 yr-1) are many times higher than projected soil nitrogen concentrations (from nitrogen deposition and release during mineralization), which preclude a rigorous evaluation of the model responses to nitrogen perturbation. Overall, we demonstrate here that elucidating ecological mechanisms via meta-analysis can identify deficiencies in both ecosystem models and empirical experiments.« less

  9. Identification and design of novel polymer-based mechanical transducers: A nano-structural model for thin film indentation

    SciTech Connect (OSTI)

    Villanueva, Joshua; Huang, Qian; Sirbuly, Donald J.

    2014-09-14

    Mechanical characterization is important for understanding small-scale systems and developing devices, particularly at the interface of biology, medicine, and nanotechnology. Yet, monitoring sub-surface forces is challenging with current technologies like atomic force microscopes (AFMs) or optical tweezers due to their probe sizes and sophisticated feedback mechanisms. An alternative transducer design relying on the indentation mechanics of a compressible thin polymer would be an ideal system for more compact and versatile probes, facilitating measurements in situ or in vivo. However, application-specific tuning of a polymer's mechanical properties can be burdensome via experimental optimization. Therefore, efficient transducer design requires a fundamental understanding of how synthetic parameters such as the molecular weight and grafting density influence the bulk material properties that determine the force response. In this work, we apply molecular-level polymer scaling laws to a first order elastic foundation model, relating the conformational state of individual polymer chains to the macroscopic compression of thin film systems. A parameter sweep analysis was conducted to observe predicted model trends under various system conditions and to understand how nano-structural elements influence the material stiffness. We validate the model by comparing predicted force profiles to experimental AFM curves for a real polymer system and show that it has reasonable predictive power for initial estimates of the force response, displaying excellent agreement with experimental force curves. We also present an analysis of the force sensitivity of an example transducer system to demonstrate identification of synthetic protocols based on desired mechanical properties. These results highlight the usefulness of this simple model as an aid for the design of a new class of compact and tunable nanomechanical force transducers.

  10. NREL Analysis: Reimagining What's Possible for Clean Energy, Continuum Magazine, Summer 2015 / Issue 8; NREL (National Renewable Energy Laboratory)

    SciTech Connect (OSTI)

    2015-08-01

    This issue of Continuum Magazine covers the depth and breadth of NREL's ever-expanding analytical capabilities. For example, in one project we are leading national efforts to create a computer model of one of the most complex systems ever built. This system, the eastern part of the North American power grid, will likely host an increasing percentage of renewable energy in years to come. Understanding how this system will work is important to its success - and NREL analysis is playing a major role. We are also identifying the connections among energy, the environment and the economy through analysis that will point us toward a 'water smart' future.

  11. Mechanical properties and modeling of seal-forming lithologies. Technical progress report No. 3, March 15, 1992--June 14, 1993

    SciTech Connect (OSTI)

    Kronenberg, A.K.; Russell, J.E.; Carter, N.L.; Mazariegos, R.; Ibanez, W.

    1993-06-01

    Specific goals and accomplishments of this research include: (1) The evaluation of models of salt diaper ascent that involve either power law, dislocation creep as determined experimentally by Horseman et al. (1993) or linear, fluid-assisted creep as reported by Spiers et al. (1988, 1990, 1992). We have compared models assuming these two, experimentally evaluated flow laws and examined the predictions they make regarding diaper incubation periods, ascent velocities, deviatoric stresses and strain rates. (2) The evaluation of the effects of differential loading on the initiation an of salt structures. (3) Examination of the role of basement faults on the initiation and morphologic evolution of salt structures. (4) Evaluation of the mechanical properties of shale as a function of pressure and determination of the nature of its brittle-ductile transition. (5) Evaluation of the mechanical anisotropies of shales with varying concentrations, distributions and preferred orientations of clay. (6) The determination of temperature and ratedependencies of strength for a shale constitutive model that can be used in numerical models that depend on viscous formulations. (7) Determination of the mechanisms of deformation for argillaceous rocks over awide range of conditions. (8) Evaluation of the effects of H{sub 2}O within clay interlayers, as adsorbed surface layers.

  12. Vehicle Technologies Office Merit Review 2014: Coupled Hierarchical Models for Thermal, Mechanical, Electrical and Electrochemical Processes

    Broader source: Energy.gov [DOE]

    Presentation given by [company name] at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about coupled hierarchical models...

  13. A simplified model for estimating population-scale energy impacts of building envelope air-tightening and mechanical ventilation retrofits

    SciTech Connect (OSTI)

    Logue, J. M.; Turner, W. J.N.; Walker, I. S.; Singer, B. C.

    2015-07-01

    Changing the air exchange rate of a home (the sum of the infiltration and mechanical ventilation airflow rates) affects the annual thermal conditioning energy. Large-scale changes to air exchange rates of the housing stock can significantly alter the residential sector’s energy consumption. However, the complexity of existing residential energy models is a barrier to the accurate quantification of the impact of policy changes on a state or national level.

  14. Coupling of Mechanical Behavior of Cell Components to Electrochemical-Thermal Models for Computer- Aided Engineering of Batteries under Abuse

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Coupling of Mechanical Behavior of Cell Components to Electrochemical-Thermal Models for Computer- Aided Engineering of Batteries under Abuse P.I.: Ahmad Pesaran Team: Tomasz Wierzbicki and Elham Sahraei (MIT) Genong Li and Lewis Collins (ANSYS) M. Sprague, G.H. Kim and S. Santhangopalan (NREL) June 17, 2014 This presentation does not contain any proprietary, confidential, or otherwise restricted information. Project ID: ES199 NREL/PR-5400-61885 2 Overview * Project Start: October 2013 * Project

  15. A Model Incorporating Some of the Mechanical and Biochemical Factors Underlying Clot Formation and Dissolution in Flowing Blood

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Anand, M.; Rajagopal, K.; Rajagopal, K. R.

    2003-01-01

    Multiple interacting mechanisms control the formation and dissolution of clots to maintain blood in a state of delicate balance. In addition to a myriad of biochemical reactions, rheological factors also play a crucial role in modulating the response of blood to external stimuli. To date, a comprehensive model for clot formation and dissolution, that takes into account the biochemical, medical and rheological factors, has not been put into place, the existing models emphasizing either one or the other of the factors. In this paper, after discussing the various biochemical, physiologic and rheological factors at some length, we develop a modelmore » for clot formation and dissolution that incorporates many of the relevant crucial factors that have a bearing on the problem. The model, though just a first step towards understanding a complex phenomenon, goes further than previous models in integrating the biochemical, physiologic and rheological factors that come into play.« less

  16. Coupled Mechanical-Electrochemical-Thermal Modeling for Accelerated Design of EV Batteries; NREL (National Renewable Energy Laboratory)

    SciTech Connect (OSTI)

    Pesaran, Ahmad; Zhang, Chao; Kim, Gi-heon; Santhanagopalan, Shriram

    2015-06-10

    The physical and chemical phenomena occurring in a battery are many and complex and in many different scales. Without a better knowledge of the interplay among the multi-physics occurring across the varied scales, it is very challenging and time consuming to design long-lasting, high-performing, safe, affordable large battery systems, enabling electrification of the vehicles and modernization of the grid. The National Renewable Energy Laboratory, a U.S. Department of Energy laboratory, has been developing thermal and electrochemical models for cells and battery packs. Working with software producers, carmakers, and battery developers, computer-aided engineering tools have been developed that can accelerate the electrochemical and thermal design of batteries, reducing time to develop and optimize them and thus reducing the cost of the system. In the past couple of years, we initiated a project to model the mechanical response of batteries to stress, strain, fracture, deformation, puncture, and crush and then link them to electrochemical and thermal models to predict the response of a battery. This modeling is particularly important for understanding the physics and processes that happen in a battery during a crush-inducing vehicle crash. In this paper, we provide an overview of electrochemical-thermal-mechanical models for battery system understanding and designing.

  17. Polycyclic aromatic hydrocarbon and mid-infrared continuum emission in a z

    Office of Scientific and Technical Information (OSTI)

    > 4 submillimeter galaxy (Journal Article) | SciTech Connect Polycyclic aromatic hydrocarbon and mid-infrared continuum emission in a z > 4 submillimeter galaxy Citation Details In-Document Search Title: Polycyclic aromatic hydrocarbon and mid-infrared continuum emission in a z > 4 submillimeter galaxy We report the detection of 6.2 μm polycyclic aromatic hydrocarbon (PAH) and rest-frame 4-7 μm continuum emission in the z = 4.055 submillimeter galaxy GN20, using the Infrared

  18. Expectations for the hard x-ray continuum and gamma-ray line fluxes from

    Office of Scientific and Technical Information (OSTI)

    the typE IA supernova SN 2014J in M82 (Journal Article) | SciTech Connect Expectations for the hard x-ray continuum and gamma-ray line fluxes from the typE IA supernova SN 2014J in M82 Citation Details In-Document Search Title: Expectations for the hard x-ray continuum and gamma-ray line fluxes from the typE IA supernova SN 2014J in M82 The hard X-ray continuum and gamma-ray lines from a Type Ia supernova dominate its integrated photon emissions and can provide unique diagnostics of the mass

  19. Controlling the width of a femtosecond continuum generated in a small-diameter fibre

    SciTech Connect (OSTI)

    Kobtsev, Sergey M; Kukarin, S V; Fateev, N V

    2002-01-31

    The control of the width of a continuum generated in a tapered germanium-doped silica fibre with the waist diameter of {approx}3 {mu}m is experimentally demonstrated for the first time. The width of the continuum was controlled by varying the wavelength of chirped femtosecond pump pulses near the zero-point of the group velocity dispersion of the fibre. The width of the continuum at the -20-dB level was varied from 98 to 790 nm by tuning the central wavelength of 80-fs, 0.6-nJ input pulses from 789 to 847 nm. (control of laser radiation parameters)

  20. DEM Particle Fracture Model

    SciTech Connect (OSTI)

    Zhang, Boning; Herbold, Eric B.; Homel, Michael A.; Regueiro, Richard A.

    2015-12-01

    An adaptive particle fracture model in poly-ellipsoidal Discrete Element Method is developed. The poly-ellipsoidal particle will break into several sub-poly-ellipsoids by Hoek-Brown fracture criterion based on continuum stress and the maximum tensile stress in contacts. Also Weibull theory is introduced to consider the statistics and size effects on particle strength. Finally, high strain-rate split Hopkinson pressure bar experiment of silica sand is simulated using this newly developed model. Comparisons with experiments show that our particle fracture model can capture the mechanical behavior of this experiment very well, both in stress-strain response and particle size redistribution. The effects of density and packings o the samples are also studied in numerical examples.

  1. From coherent to incoherent mismatched interfaces. A generalized continuum formulation of surface stresses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dingreville, Rémi; Hallil, Abdelmalek; Berbenni, Stéphane

    2014-08-19

    The equilibrium of coherent and incoherent mismatched interfaces is reformulated in the context of continuum mechanics based on the Gibbs dividing surface concept. Two surface stresses are introduced: a coherent surface stress and an incoherent surface stress, as well as a transverse excess strain. Additionally, the coherent surface stress and the transverse excess strain represent the thermodynamic driving forces of stretching the interface while the incoherent surface stress represents the driving force of stretching one crystal while holding the other fixed and thereby altering the structure of the interface. These three quantities fully characterize the elastic behavior of coherent andmore » incoherent interfaces as a function of the in-plane strain, the transverse stress and the mismatch strain. The isotropic case is developed in detail and particular attention is paid to the case of interfacial thermo-elasticity. This exercise provides an insight on the physical significance of the interfacial elastic constants introduced in the formulation and illustrates the obvious coupling between the interface structure and its associated thermodynamics quantities. Finally, an example based on atomistic simulations of Cu/Cu2O interfaces is given to demonstrate the relevance of the generalized interfacial formulation and to emphasize the dependence of the interfacial thermodynamic quantities on the incoherency strain with an actual material system.« less

  2. NARROWBAND IMAGING OF ESCAPING LYMAN-CONTINUUM EMISSION IN THE SSA22 FIELD

    SciTech Connect (OSTI)

    Nestor, Daniel B.; Shapley, Alice E.; Steidel, Charles C.; Siana, Brian

    2011-07-20

    We present the results of an ultradeep, narrowband imaging survey for Lyman-continuum (LyC) emission at z {approx} 3 in the SSA22a field. We employ a custom narrowband filter centered at {lambda} = 3640 A (NB3640), which probes the LyC region for galaxies at z {>=} 3.06. We also analyze new and archival NB4980 imaging tuned to the wavelength of the Ly{alpha} emission line at z = 3.09, and archival broadband B, V, and R images of the non-ionizing UV continuum. Our NB3640 images contain 26 z {>=} 3.06 Lyman break galaxies (LBGs) as well as a set of 130 Ly{alpha} emitters (LAEs), identified by their excess NB4980 flux relative to the BV continuum. Six LBGs and 28 LAEs are detected in the NB3640 image. LBGs appear to span a range of NB3640-R colors, while LAEs appear bimodal in their NB3640-R properties. We estimate average UV-to-LyC flux density ratios, corrected for foreground contamination and intergalactic medium absorption, finding (F{sub UV}/F{sub LyC}){sup LBG}{sub corr} = 11.3{sup +10.3}{sub -5.4}, which implies an LBG LyC escape fraction f{sup LyC}{sub esc} {approx} 0.1, and (F{sub UV}/F{sub LyC}){sup LAE}{sub corr} = 2.2{sup +0.9}{sub -0.6}. The strikingly blue LAE flux density ratios defy interpretation in terms of standard stellar population models. Assuming (F{sub UV}/F{sub LyC}){sup LBG}{sub corr} applies down to L = 0.1L*, we estimate a galaxy contribution to the intergalactic hydrogen ionization rate that is consistent with independent estimates based on the Ly{alpha} forest opacity at z {approx_equal} 3. If we assume that (F{sub UV}/F{sub LyC}){sup LAE}{sub corr} holds at the faintest luminosities, the galaxy contribution significantly exceeds that inferred from the Ly{alpha} forest. We interpret our results in terms of a model where LyC photons escape over only {approx}10%-20% of solid angle. When advantageously oriented, a galaxy will exhibit a low UV-to-LyC ratio, an effect enhanced for more compact galaxies. This model, however, does not adequately explain the extremely blue NB3640-R colors measured for some LAEs in our sample. Further follow-up study of these faint LAEs is crucial, given the potentially important contribution similar objects make to the process of reionization.

  3. Experimental and Modeling Characterization of PETN Mobilization Mechanisms During Recrystallization at Ambient Conditions

    SciTech Connect (OSTI)

    Burnham, A K; Gee, R; Maiti, A; Qiu, R; Rajasekar, P; Weeks, B; Zepeda-Ruiz, L

    2005-11-03

    Experimental measurements suggest that pentaerythritoltetranitrate (PETN) undergoes changes at the molecular level that cause macroscopic changes in the overall PETN powder characteristics over time. These changes have been attributed to the high molecular mobility of PETN, but the underlying mechanism(s) responsible for this redistribution are still uncertain. Two basic approaches have been implemented in the past year to provide insight into the nature of these underlying mechanisms. The first approach is of an experimental nature, utilizing both AFM and evaporation measurements, which address both surface mobility and evaporation. These data include AFM measurements performed at LLNL and evaporation rate measurements performed at Texas Tech. These results are compared to earlier vapor pressure measurements performed at SNL, and estimates of recrystallization time frames are given. The second approach utilizes first-principle calculations and simulations that will be used to compare directly to those experimental quantities measured. We are developing an accurate intermolecular potential for PETN, which via kinetic Monte Carlo (KMC) simulations would mimic real crystallite shapes. Once the basic theory is in place for the growth of single crystallites, we will be in a position to investigate realistic grain coarsening phenomena in multi-crystallite simulations. This will also enable us to study how to control the morphological evolution, e.g., through thermal cycling, or through the action of custom additives and impurities.

  4. A simplified model for estimating population-scale energy impacts of building envelope air-tightening and mechanical ventilation retrofits

    SciTech Connect (OSTI)

    Logue, Jennifer M.; Turner, William J. N.; Walker, Iain S.; Singer, Brett C.

    2015-01-19

    Changing the air exchange rate of a home (the sum of the infiltration and mechanical ventilation airflow rates) affects the annual thermal conditioning energy. Large-scale changes to air exchange rates of the housing stock can significantly alter the residential sector's energy consumption. However, the complexity of existing residential energy models is a barrier to the accurate quantification of the impact of policy changes on a state or national level. The Incremental Ventilation Energy (IVE) model developed in this study combines the output of simple air exchange models with a limited set of housing characteristics to estimate the associated change in energy demand of homes. The IVE model was designed specifically to enable modellers to use existing databases of housing characteristics to determine the impact of ventilation policy change on a population scale. The IVE model estimates of energy change when applied to US homes with limited parameterisation are shown to be comparable to the estimates of a well-validated, complex residential energy model.

  5. Particle-scale CO2 adsorption kinetics modeling considering three reaction mechanisms

    SciTech Connect (OSTI)

    Suh, Dong-Myung; Sun, Xin

    2013-09-01

    In the presence of water (H2O), dry and wet adsorptions of carbon dioxide (CO2) and physical adsorption of H2O happen concurrently in a sorbent particle. The three reactions depend on each other and have a complicated, but important, effect on CO2 capturing via a solid sorbent. In this study, transport phenomena in the sorbent were modeled, including the tree reactions, and a numerical solving procedure for the model also was explained. The reaction variable distribution in the sorbent and their average values were calculated, and simulation results were compared with experimental data to validate the proposed model. Some differences, caused by thermodynamic parameters, were observed between them. However, the developed model reasonably simulated the adsorption behaviors of a sorbent. The weight gained by each adsorbed species, CO2 and H2O, is difficult to determine experimentally. It is known that more CO2 can be captured in the presence of water. Still, it is not yet known quantitatively how much more CO2 the sorbent can capture, nor is it known how much dry and wet adsorptions separately account for CO2 capture. This study addresses those questions by modeling CO2 adsorption in a particle and simulating the adsorption process using the model. As adsorption temperature changed into several values, the adsorbed amount of each species was calculated. The captured CO2 in the sorbent particle was compared quantitatively between dry and wet conditions. As the adsorption temperature decreased, wet adsorption increased. However, dry adsorption was reduced.

  6. Constriction model of actomyosin ring for cytokinesis by fission yeast using a two-state sliding filament mechanism

    SciTech Connect (OSTI)

    Jung, Yong-Woon; Mascagni, Michael

    2014-09-28

    We developed a model describing the structure and contractile mechanism of the actomyosin ring in fission yeast, Schizosaccharomyces pombe. The proposed ring includes actin, myosin, and ?-actinin, and is organized into a structure similar to that of muscle sarcomeres. This structure justifies the use of the sliding-filament mechanism developed by Huxley and Hill, but it is probably less organized relative to that of muscle sarcomeres. Ring contraction tension was generated via the same fundamental mechanism used to generate muscle tension, but some physicochemical parameters were adjusted to be consistent with the proposed ring structure. Simulations allowed an estimate of ring constriction tension that reproduced the observed ring constriction velocity using a physiologically possible, self-consistent set of parameters. Proposed molecular-level properties responsible for the thousand-fold slower constriction velocity of the ring relative to that of muscle sarcomeres include fewer myosin molecules involved, a less organized contractile configuration, a low ?-actinin concentration, and a high resistance membrane tension. Ring constriction velocity is demonstrated as an exponential function of time despite a near linear appearance. We proposed a hypothesis to explain why excess myosin heads inhibit constriction velocity rather than enhance it. The model revealed how myosin concentration and elastic resistance tension are balanced during cytokinesis in S. pombe.

  7. Integral Relations for Three-Body Continuum States with the Adiabatic

    Office of Scientific and Technical Information (OSTI)

    Expansion (Journal Article) | SciTech Connect Integral Relations for Three-Body Continuum States with the Adiabatic Expansion Citation Details In-Document Search Title: Integral Relations for Three-Body Continuum States with the Adiabatic Expansion The application of the hyperspherical adiabatic expansion to describe three-body scattering states suffers from the problem of very slow convergence. Contrary to what happens for bound states, a huge number of hyper-radial equations has to be

  8. Development of Advanced Thermal-Hydrological-Mechanical-Chemical (THMC) Modeling Capabilities for Enhanced Geothermal Systems

    Broader source: Energy.gov [DOE]

    Project objectives: Develop a general framework for effective flow of water, steam and heat in in porous and fractured geothermal formations. Develop a computational module for handling coupled effects of pressure, temperature, and induced rock deformations. Develop a reliable model of heat transfer and fluid flow in fractured rocks.

  9. A quantum mechanical model for the relationship between stock price and stock ownership

    SciTech Connect (OSTI)

    Cotfas, Liviu-Adrian

    2012-11-01

    The trade of a fixed stock can be regarded as the basic process that measures its momentary price. The stock price is exactly known only at the time of sale when the stock is between traders, that is, only in the case when the owner is unknown. We show that the stock price can be better described by a function indicating at any moment of time the probabilities for the possible values of price if a transaction takes place. This more general description contains partial information on the stock price, but it also contains partial information on the stock owner. By following the analogy with quantum mechanics, we assume that the time evolution of the function describing the stock price can be described by a Schroedinger type equation.

  10. Melanin, a promising radioprotector: Mechanisms of actions in a mice model

    SciTech Connect (OSTI)

    Kunwar, A.; Adhikary, B.; Jayakumar, S.; Barik, A.; Chattopadhyay, S.; Raghukumar, S.; Priyadarsini, K.I.

    2012-10-15

    The radioprotective effect of extracellular melanin, a naturally occurring pigment, isolated from the fungus Gliocephalotrichum simplex was examined in BALB/C mice, and the probable mechanism of action was established. At an effective dose of 50 mg/kg body weight, melanin exhibited both prophylactic and mitigative activities, increasing the 30-day survival of mice by 100% and 60%, respectively, after exposure to radiation (7 Gy, whole body irradiation (WBI)). The protective activity of melanin was primarily due to inhibition of radiation-induced hematopoietic damages as evidenced by improvement in spleen parameters such as index, total cellularity, endogenous colony forming units, and maintenance of circulatory white blood cells and platelet counts. Melanin also reversed the radiation-induced decrease in ERK phosphorylation in splenic tissue, which may be the key feature in its radioprotective action. Additionally, our results indicated that the sustained activation of AKT, JNK and P38 proteins in splenic tissue of melanin pre-treated group may also play a secondary role. This was also supported by the fact that melanin could prevent apoptosis in splenic tissue by decreasing BAX/Bcl-XL ratio, and increasing the expressions of the proliferation markers (PCNA and Cyclin D1), compared to the radiation control group. Melanin also reduced the oxidative stress in hepatic tissue and abrogated immune imbalance by reducing the production of pro-inflammatory cytokines (IL6 and TNF?). In conclusion, our results confirmed that fungal melanin is a very effective radioprotector against WBI and the probable mechanisms of radioprotection are due to modulation in pro-survival (ERK) signaling, prevention of oxidative stress and immunomodulation. -- Highlights: ? Melanin showed promising radioprotection under pre and post irradiation condition. ? Melanin protects the hematopoietic system from radiation induced damage. ? Melanin modulates pro-survival pathways, immune system and prevents oxidative stress.

  11. Probing primordial non-Gaussianity via iSW measurements with SKA continuum surveys

    SciTech Connect (OSTI)

    Raccanelli, Alvise; Dor, Olivier E-mail: olivier.dore@caltech.edu; Bacon, David J.; Maartens, Roy E-mail: roy.maartens@gmail.com; and others

    2015-01-01

    The Planck CMB experiment has delivered the best constraints so far on primordial non-Gaussianity, ruling out early-Universe models of inflation that generate large non-Gaussianity. Although small improvements in the CMB constraints are expected, the next frontier of precision will come from future large-scale surveys of the galaxy distribution. The advantage of such surveys is that they can measure many more modes than the CMBin particular, forthcoming radio surveys with the Square Kilometre Array will cover huge volumes. Radio continuum surveys deliver the largest volumes, but with the disadvantage of no redshift information. In order to mitigate this, we use two additional observables. First, the integrated Sachs-Wolfe effectthe cross-correlation of the radio number counts with the CMB temperature anisotropieshelps to reduce systematics on the large scales that are sensitive to non-Gaussianity. Second, optical data allows for cross-identification in order to gain some redshift information. We show that, while the single redshift bin case can provide a ?(f{sub NL})?20, and is therefore not competitive with current and future constraints on non-Gaussianity, a tomographic analysis could improve the constraints by an order of magnitude, even with only two redshift bins. A huge improvement is provided by the addition of high-redshift sources, so having cross-ID for high-z galaxies and an even higher-z radio tail is key to enabling very precise measurements of f{sub NL}. We use Fisher matrix forecasts to predict the constraining power in the case of no redshift information and the case where cross-ID allows a tomographic analysis, and we show that the constraints do not improve much with 3 or more bins. Our results show that SKA continuum surveys could provide constraints competitive with CMB and forthcoming optical surveys, potentially allowing a measurement of ?(f{sub NL})?1 to be made. Moreover, these measurements would act as a useful check of results obtained with other probes at other redshift ranges with other methods.

  12. Injection-Molded Long-Fiber Thermoplastic Composites: From Process Modeling to Prediction of Mechanical Properties

    SciTech Connect (OSTI)

    Nguyen, Ba Nghiep; Kunc, Vlastimil; Jin, Xiaoshi; Tucker III, Charles L.; Costa, Franco

    2013-12-18

    This article illustrates the predictive capabilities for long-fiber thermoplastic (LFT) composites that first simulate the injection molding of LFT structures by Autodesk Simulation Moldflow Insight (ASMI) to accurately predict fiber orientation and length distributions in these structures. After validating fiber orientation and length predictions against the experimental data, the predicted results are used by ASMI to compute distributions of elastic properties in the molded structures. In addition, local stress-strain responses and damage accumulation under tensile loading are predicted by an elastic-plastic damage model of EMTA-NLA, a nonlinear analysis tool implemented in ABAQUS via user-subroutines using an incremental Eshelby-Mori-Tanaka approach. Predicted stress-strain responses up to failure and damage accumulations are compared to the experimental results to validate the model.

  13. Modeling the hydro-mechanical responses of strip and circular punch loadings on water-saturated collapsible geomaterials

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sun, WaiChing; Chen, Qiushi; Ostien, Jakob T.

    2013-11-22

    A stabilized enhanced strain finite element procedure for poromechanics is fully integrated with an elasto-plastic cap model to simulate the hydro-mechanical interactions of fluid-infiltrating porous rocks with associative and non-associative plastic flow. We present a quantitative analysis on how macroscopic plastic volumetric response caused by pore collapse and grain rearrangement affects the seepage of pore fluid, and vice versa. Results of finite element simulations imply that the dissipation of excess pore pressure may significantly affect the stress path and thus alter the volumetric plastic responses.

  14. Modeling oscillatory dynamics in brain microcircuits as a way to help uncover neurological disease mechanisms: A proposal

    SciTech Connect (OSTI)

    Skinner, F. K.; Department of Medicine , University of Toronto, 200 Elizabeth Street, Toronto, Ontario M5G 2C4; Department of Physiology, University of Toronto Medical Sciences Building, 3rd Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8 ; Ferguson, K. A.; Department of Physiology, University of Toronto Medical Sciences Building, 3rd Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8

    2013-12-15

    There is an undisputed need and requirement for theoretical and computational studies in Neuroscience today. Furthermore, it is clear that oscillatory dynamical output from brain networks is representative of various behavioural states, and it is becoming clear that one could consider these outputs as measures of normal and pathological brain states. Although mathematical modeling of oscillatory dynamics in the context of neurological disease exists, it is a highly challenging endeavour because of the many levels of organization in the nervous system. This challenge is coupled with the increasing knowledge of cellular specificity and network dysfunction that is associated with disease. Recently, whole hippocampus in vitro preparations from control animals have been shown to spontaneously express oscillatory activities. In addition, when using preparations derived from animal models of disease, these activities show particular alterations. These preparations present an opportunity to address challenges involved with using models to gain insight because of easier access to simultaneous cellular and network measurements, and pharmacological modulations. We propose that by developing and using models with direct links to experiment at multiple levels, which at least include cellular and microcircuit, a cycling can be set up and used to help us determine critical mechanisms underlying neurological disease. We illustrate our proposal using our previously developed inhibitory network models in the context of these whole hippocampus preparations and show the importance of having direct links at multiple levels.

  15. Class of model problems in three-body quantum mechanics that admit exact solutions

    SciTech Connect (OSTI)

    Takibayev, N. Zh.

    2008-03-15

    An approach to solving scattering problems in three-body systems for cases where the mass of one of the particles is extremely small in relation to the masses of the other two particles and where the pair potentials of interaction between the particles involved are separable is developed. Exact analytic solutions to such model problems are found for the scattering of a light particle on two fixed centers and on two interacting heavy particles. It is shown that new resonances and a dynamical resonance enhancement may appear in a three-body system.

  16. A Process and Environment Aware Sierra/SolidMechanics Cohesive Zone Modeling Capability for Polymer/Solid Interfaces

    SciTech Connect (OSTI)

    Reedy, E. D.; Chambers, Robert S.; Hughes, Lindsey Gloe; Kropka, Jamie Michael; Stavig, Mark E.; Stevens, Mark J.

    2015-09-01

    The performance and reliability of many mechanical and electrical components depend on the integrity of po lymer - to - solid interfaces . Such interfaces are found in adhesively bonded joints, encapsulated or underfilled electronic modules, protective coatings, and laminates. The work described herein was aimed at improving Sandia's finite element - based capability to predict interfacial crack growth by 1) using a high fidelity nonlinear viscoelastic material model for the adhesive in fracture simulations, and 2) developing and implementing a novel cohesive zone fracture model that generates a mode - mixity dependent toughness as a natural consequence of its formulation (i.e., generates the observed increase in interfacial toughness wi th increasing crack - tip interfacial shear). Furthermore, molecular dynamics simulations were used to study fundamental material/interfa cial physics so as to develop a fuller understanding of the connection between molecular structure and failure . Also reported are test results that quantify how joint strength and interfacial toughness vary with temperature.

  17. Adsorption of small weak organic acids on goethite: Modeling of mechanisms

    SciTech Connect (OSTI)

    Filius, J.D.; Hiemstra, T.; Riemsdijk, W.H. Van

    1997-11-15

    The adsorption of lactate, oxalate, malonate, phthalate, and citrate has been determined experimentally as a function of concentration, pH, and ionic strength. The data have been described with the CD-MUSIC model of Hiemstra and Van Riemsdijk which allows a distribution of charge of the organic molecule over the surface and the Stern layer. Simultaneously, the concentration, pH, and salt dependency as well as the basic charging behavior of goethite could be described well. On the basis of model calculations, a distinction is made between inner and outer sphere complexation of weak organic acids by goethite. The results indicate that the affinity of the organic acids is dominated by the electrostatic attraction. The intrinsic affinity constants for the exchange reaction of surface water groups and organic acids, expressed per bond, increases with increasing number of reactive groups on the organic molecule. Ion pair formation between noncoordinated carboxylic groups of adsorbed organic acids and cations of the background electrolyte proved to be important for the salt dependency. The knowledge obtained may contribute to the interpretation of the binding of larger organic acids like fulvic and humic acids.

  18. Discriminating binding mechanisms of an intrinsically disordered protein via a multi-state coarse-grained model

    SciTech Connect (OSTI)

    Knott, Michael [Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW (United Kingdom)] [Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Best, Robert B., E-mail: robertbe@helix.nih.gov [Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520 (United States)

    2014-05-07

    Many proteins undergo a conformational transition upon binding to their cognate binding partner, with intrinsically disordered proteins (IDPs) providing an extreme example in which a folding transition occurs. However, it is often not clear whether this occurs via an induced fit or conformational selection mechanism, or via some intermediate scenario. In the first case, transient encounters with the binding partner favour transitions to the bound structure before the two proteins dissociate, while in the second the bound structure must be selected from a subset of unbound structures which are in the correct state for binding, because transient encounters of the incorrect conformation with the binding partner are most likely to result in dissociation. A particularly interesting situation involves those intrinsically disordered proteins which can bind to different binding partners in different conformations. We have devised a multi-state coarse-grained simulation model which is able to capture the binding of IDPs in alternate conformations, and by applying it to the binding of nuclear coactivator binding domain (NCBD) to either ACTR or IRF-3 we are able to determine the binding mechanism. By all measures, the binding of NCBD to either binding partner appears to occur via an induced fit mechanism. Nonetheless, we also show how a scenario closer to conformational selection could arise by choosing an alternative non-binding structure for NCBD.

  19. Adaptive Breast Radiation Therapy Using Modeling of Tissue Mechanics: A Breast Tissue Segmentation Study

    SciTech Connect (OSTI)

    Juneja, Prabhjot; Harris, Emma J.; Kirby, Anna M.; Evans, Philip M.

    2012-11-01

    Purpose: To validate and compare the accuracy of breast tissue segmentation methods applied to computed tomography (CT) scans used for radiation therapy planning and to study the effect of tissue distribution on the segmentation accuracy for the purpose of developing models for use in adaptive breast radiation therapy. Methods and Materials: Twenty-four patients receiving postlumpectomy radiation therapy for breast cancer underwent CT imaging in prone and supine positions. The whole-breast clinical target volume was outlined. Clinical target volumes were segmented into fibroglandular and fatty tissue using the following algorithms: physical density thresholding; interactive thresholding; fuzzy c-means with 3 classes (FCM3) and 4 classes (FCM4); and k-means. The segmentation algorithms were evaluated in 2 stages: first, an approach based on the assumption that the breast composition should be the same in both prone and supine position; and second, comparison of segmentation with tissue outlines from 3 experts using the Dice similarity coefficient (DSC). Breast datasets were grouped into nonsparse and sparse fibroglandular tissue distributions according to expert assessment and used to assess the accuracy of the segmentation methods and the agreement between experts. Results: Prone and supine breast composition analysis showed differences between the methods. Validation against expert outlines found significant differences (P<.001) between FCM3 and FCM4. Fuzzy c-means with 3 classes generated segmentation results (mean DSC = 0.70) closest to the experts' outlines. There was good agreement (mean DSC = 0.85) among experts for breast tissue outlining. Segmentation accuracy and expert agreement was significantly higher (P<.005) in the nonsparse group than in the sparse group. Conclusions: The FCM3 gave the most accurate segmentation of breast tissues on CT data and could therefore be used in adaptive radiation therapy-based on tissue modeling. Breast tissue segmentation methods should be used with caution in patients with sparse fibroglandular tissue distribution.

  20. Adsorption Mechanisms of Trivalent Gold onto Iron Oxy-Hydroxides: From the Molecular Scale to the Model

    SciTech Connect (OSTI)

    Cances, Benjamin; Benedetti, Marc; Farges, Francois; Brown, Gordon E. Jr.

    2007-02-02

    Gold is a highly valuable metal that can concentrate in iron-rich exogenetic horizons such as laterites. An improved knowledge of the retention mechanisms of gold onto highly reactive soil components such as iron oxy-hydroxides is therefore needed to better understand and predict the geochemical behavior of this element. In this study, we use EXAFS information and titration experiments to provide a realistic thermochemical description of the sorption of trivalent gold onto iron oxy-hydroxides. Analysis of Au LIII-edge XAFS spectra shows that aqueous Au(III) adsorbs from chloride solutions onto goethite surfaces as inner-sphere square-planar complexes (Au(III)(OH,Cl)4), with dominantly OH ligands at pH > 6 and mixed OH/Cl ligands at lower pH values. In combination with these spectroscopic results, Reverse Monte Carlo simulations were used to constraint the possible sorption sites on the surface of goethite. Based on this structural information, we calculated sorption isotherms of Au(III) on Fe oxy-hydroxides surfaces, using the CD-MUSIC (Charge Distribution - MUlti SIte Complexation) model. The various Au(III)-sorbed species were identified as a function of pH, and the results of these EXAFS+CD-MUSIC models are compared with titration experiments. The overall good agreement between the predicted and measured structural models shows the potential of this combined approach to better model sorption processes of transition elements onto highly reactive solid surfaces such as goethite and ferrihydrite.

  1. SEACAS Theory Manuals: Part III. Finite Element Analysis in Nonlinear Solid Mechanics

    SciTech Connect (OSTI)

    Laursen, T.A.; Attaway, S.W.; Zadoks, R.I.

    1999-03-01

    This report outlines the application of finite element methodology to large deformation solid mechanics problems, detailing also some of the key technological issues that effective finite element formulations must address. The presentation is organized into three major portions: first, a discussion of finite element discretization from the global point of view, emphasizing the relationship between a virtual work principle and the associated fully discrete system, second, a discussion of finite element technology, emphasizing the important theoretical and practical features associated with an individual finite element; and third, detailed description of specific elements that enjoy widespread use, providing some examples of the theoretical ideas already described. Descriptions of problem formulation in nonlinear solid mechanics, nonlinear continuum mechanics, and constitutive modeling are given in three companion reports.

  2. Development Status of the PEBBLES Code for Pebble Mechanics: Improved Physical Models and Speed-up

    SciTech Connect (OSTI)

    Joshua J. Cogliati; Abderrafi M. Ougouag

    2009-12-01

    PEBBLES is a code for simulating the motion of all the pebbles in a pebble bed reactor. Since pebble bed reactors are packed randomly and not precisely placed, the location of the fuel elements in the reactor is not deterministically known. Instead, when determining operating parameters the motion of the pebbles can be simulated and stochastic locations can be found. The PEBBLES code can output information relevant for other simulations of the pebble bed reactors such as the positions of the pebbles in the reactor, packing fraction change in an earthquake, and velocity profiles created by recirculation. The goal for this level three milestone was to speedup the PEBBLES code through implementation on massively parallel computer. Work on this goal has resulted in speeding up both the single processor version and creation of a new parallel version of PEBBLES. Both the single processor version and the parallel running capability of the PEBBLES code have improved since the fiscal year start. The hybrid MPI/OpenMP PEBBLES version was created this year to run on the increasingly common cluster hardware profile that combines nodes with multiple processors that share memory and a cluster of nodes that are networked together. The OpenMP portions use the Open Multi-Processing shared memory parallel processing model to split the task across processors in a single node that shares memory. The Message Passing Interface (MPI) portion uses messages to communicate between different nodes over a network. The following are wall clock speed up for simulating an NGNP-600 sized reactor. The single processor version runs 1.5 times faster compared to the single processor version at the beginning of the fiscal year. This speedup is primarily due to the improved static friction model described in the report. When running on 64 processors, the new MPI/OpenMP hybrid version has a wall clock speed up of 22 times compared to the current single processor version. When using 88 processors, a speed up of 23 times is achieved. This speedup and other improvements of PEBBLES combine to make PEBBLES more capable and more useful for simulation of a pebble bed reactor. This report details the implementation and effects of the speedup work done over the course of the fiscal year.

  3. Development Status of the PEBBLES Code for Pebble Mechanics: Improved Physical Models and Speed-up

    SciTech Connect (OSTI)

    Joshua J. Cogliati; Abderrafi M. Ougouag

    2009-09-01

    PEBBLES is a code for simulating the motion of all the pebbles in a pebble bed reactor. Since pebble bed reactors are packed randomly and not precisely placed, the location of the fuel elements in the reactor is not deterministically known. Instead, when determining operating parameters the motion of the pebbles can be simulated and stochastic locations can be found. The PEBBLES code can output information relevant for other simulations of the pebble bed reactors such as the positions of the pebbles in the reactor, packing fraction change in an earthquake, and velocity profiles created by recirculation. The goal for this level three milestone was to speedup the PEBBLES code through implementation on massively parallel computer. Work on this goal has resulted in speeding up both the single processor version and creation of a new parallel version of PEBBLES. Both the single processor version and the parallel running capability of the PEBBLES code have improved since the fiscal year start. The hybrid MPI/OpenMP PEBBLES version was created this year to run on the increasingly common cluster hardware profile that combines nodes with multiple processors that share memory and a cluster of nodes that are networked together. The OpenMP portions use the Open Multi-Processing shared memory parallel processing model to split the task across processors in a single node that shares memory. The Message Passing Interface (MPI) portion uses messages to communicate between different nodes over a network. The following are wall clock speed up for simulating an NGNP-600 sized reactor. The single processor version runs 1.5 times faster compared to the single processor version at the beginning of the fiscal year. This speedup is primarily due to the improved static friction model described in the report. When running on 64 processors, the new MPI/OpenMP hybrid version has a wall clock speed up of 22 times compared to the current single processor version. When using 88 processors, a speed up of 23 times is achieved. This speedup and other improvements of PEBBLES combine to make PEBBLES more capable and more useful for simulation of a pebble bed reactor. This report details the implementation and effects of the speedup work done over the course of the fiscal year.

  4. A SPECTROSCOPIC SEARCH FOR LEAKING LYMAN CONTINUUM AT z {approx} 0.7

    SciTech Connect (OSTI)

    Bridge, Carrie R.; Siana, Brian; Salvato, Mara; Rudie, Gwen C.; Teplitz, Harry I.; Scarlata, Claudia; Colbert, James; Armus, Lee; Conselice, Christopher J.; Ferguson, Henry C.; Brown, Thomas M.; Giavalisco, Mauro; De Mello, Duilia F.; Gardner, Jonathan P.

    2010-09-01

    We present the results of rest-frame, UV slitless spectroscopic observations of a sample of 32 z {approx} 0.7 Lyman break galaxy (LBG) analogs in the COSMOS field. The spectroscopic search was performed with the Solar Blind Channel on the Hubble Space Telescope. We report the detection of leaking Lyman continuum (LyC) radiation from an active galactic nucleus-starburst composite. While we find no direct detections of LyC emission in the remainder of our sample, we achieve individual lower limits (3{sigma}) of the observed non-ionizing UV-to-LyC flux density ratios, f{sub {nu}} (1500 A)/f{sub {nu}}(830 A) of 20 to 204 (median of 73.5) and 378.7 for the stack. Assuming an intrinsic Lyman break of 3.4 and an intergalactic medium transmission of LyC photons along the line of sight to the galaxy of 85%, we report an upper limit for the relative escape fraction in individual galaxies of 0.02-0.19 and a stacked 3{sigma} upper limit of 0.01. We find no indication of a relative escape fraction near unity as seen in some LBGs at z {approx} 3. Our UV spectra achieve the deepest limits to date at any redshift for the escape fraction in individual sources. The contrast between these z {approx} 0.7 low escape fraction LBG analogs with z {approx} 3 LBGs suggests that either the processes conducive to high f{sub esc} are not being selected for in the z {approx}< 1 samples or the average escape fraction is decreasing from z {approx} 3 to z {approx} 1. We discuss possible mechanisms that could affect the escape of LyC photons.

  5. Continuum absorption in the vicinity of the toroidicity-induced Alfvén gap

    SciTech Connect (OSTI)

    Li, M.; Breizman, B. N.; Zheng, L. J.; Chen, Eugene Y.

    2015-12-04

    Excitation of Alfvén modes is commonly viewed as a concern for energetic particle confinement in burning plasmas. The 3.5 MeValpha particles produced by fusion may be affected as well as other fast ions in both present and future devices. Continuum damping of such modes is one of the key factors that determine their excitation thresholds and saturation levels. This work examines the resonant dissipative response of the Alfvén continuum to an oscillating driving current when the driving frequency is slightly outside the edges of the toroidicity-induced spectral gap. The problem is largely motivated by the need to describe the continuum absorption in the frequency sweeping events. Akey element of this problem is the negative interference of the two closely spaced continuum crossing points.Weexplain why the lower and upper edges of the gap can have very different continuum absorption features. Lastly, the difference is associated with an eigenmode whose frequency can be arbitrarily close to the upper edge of the gap whereas the lower edge of the gap is always a finite distance away from the closest eigenmode.

  6. Performance Evaluation of K-DEMO Cable-in-conduit Conductors Using the Florida Electro-Mechanical Cable Model

    SciTech Connect (OSTI)

    Zhai, Yuhu

    2013-07-16

    The United States ITER Project Office (USIPO) is responsible for design of the Toroidal Field (TF) insert coil, which will allow validation of the performance of significant lengths of the conductors to be used in the full scale TF coils in relevant conditions of field, current density and mechanical strain. The Japan Atomic Energy Agency (JAEA) will build the TF insert which will be tested at the Central Solenoid Model Coil (CSMC) Test facility at JAEA, Naka, Japan. Three dimensional mathematical model of TF Insert was created based on the initial design geometry data, and included the following features: orthotropic material properties of superconductor material and insulation; external magnetic field from CSMC, temperature dependent properties of the materials; pre-compression and plastic deformation in lap joint. Major geometrical characteristics of the design were preserved including cable jacket and insulation shape, mandrel outline, and support clamps and spacers. The model is capable of performing coupled structural, thermal, and electromagnetic analysis using ANSYS. Numerical simulations were performed for room temperature conditions; cool down to 4K, and the operating regime with 68kA current at 11.8 Tesla background field. Numerical simulations led to the final design of the coil producing the required strain levels on the cable, while simultaneously satisfying the ITER magnet structural design criteria.

  7. Electron density and temperature measurement by continuum radiation emitted from weakly ionized atmospheric pressure plasmas

    SciTech Connect (OSTI)

    Park, Sanghoo; Choe, Wonho, E-mail: wchoe@kaist.ac.kr [Department of Physics, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Youn Moon, Se [High-enthalpy Plasma Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju 561-756 (Korea, Republic of); Park, Jaeyoung [5771 La Jolla Corona Drive, La Jolla, CA 92037 (United States)

    2014-02-24

    The electron-atom neutral bremsstrahlung continuum radiation emitted from weakly ionized plasmas is investigated for electron density and temperature diagnostics. The continuum spectrum in 4501000?nm emitted from the argon atmospheric pressure plasma is found to be in excellent agreement with the neutral bremsstrahlung formula with the electron-atom momentum transfer cross-section given by Popovi?. In 280450?nm, however, a large discrepancy between the measured and the neutral bremsstrahlung emissivities is observed. We find that without accounting for the radiative H{sub 2} dissociation continuum, the temperature, and density measurements would be largely wrong, so that it should be taken into account for accurate measurement.

  8. THERMO-HYDRO-MECHANICAL MODELING OF WORKING FLUID INJECTION AND THERMAL ENERGY EXTRACTION IN EGS FRACTURES AND ROCK MATRIX

    SciTech Connect (OSTI)

    Robert Podgorney; Chuan Lu; Hai Huang

    2012-01-01

    Development of enhanced geothermal systems (EGS) will require creation of a reservoir of sufficient volume to enable commercial-scale heat transfer from the reservoir rocks to the working fluid. A key assumption associated with reservoir creation/stimulation is that sufficient rock volumes can be hydraulically fractured via both tensile and shear failure, and more importantly by reactivation of naturally existing fractures (by shearing), to create the reservoir. The advancement of EGS greatly depends on our understanding of the dynamics of the intimately coupled rock-fracture-fluid-heat system and our ability to reliably predict how reservoirs behave under stimulation and production. Reliable performance predictions of EGS reservoirs require accurate and robust modeling for strongly coupled thermal-hydrological-mechanical (THM) processes. Conventionally, these types of problems have been solved using operator-splitting methods, usually by coupling a subsurface flow and heat transport simulators with a solid mechanics simulator via input files. An alternative approach is to solve the system of nonlinear partial differential equations that govern multiphase fluid flow, heat transport, and rock mechanics simultaneously, using a fully coupled, fully implicit solution procedure, in which all solution variables (pressure, enthalpy, and rock displacement fields) are solved simultaneously. This paper describes numerical simulations used to investigate the poro- and thermal- elastic effects of working fluid injection and thermal energy extraction on the properties of the fractures and rock matrix of a hypothetical EGS reservoir, using a novel simulation software FALCON (Podgorney et al., 2011), a finite element based simulator solving fully coupled multiphase fluid flow, heat transport, rock deformation, and fracturing using a global implicit approach. Investigations are also conducted on how these poro- and thermal-elastic effects are related to fracture permeability evolution.

  9. Adsorption Mechanisms of Trivalent Gold onto Iron Oxy-Hydroxides: From the Molecular Scale to the Model

    SciTech Connect (OSTI)

    Cances, Benjamin; Benedetti, Marc; Farges, Francois; Brown, Gordon E.., Jr.; /Stanford U., Geo. Environ. Sci. /SLAC, SSRL

    2006-12-13

    Gold is a highly valuable metal that can concentrate in iron-rich exogenetic horizons such as laterites. An improved knowledge of the retention mechanisms of gold onto highly reactive soil components such as iron oxyhydroxides is therefore needed to better understand and predict the geochemical behavior of this element. In this study, we use EXAFS information and titration experiments to provide a realistic thermochemical description of the sorption of trivalent gold onto iron oxy-hydroxides. Analysis of Au L{sub III}-edge XAFS spectra shows that aqueous Au(III) adsorbs from chloride solutions onto goethite surfaces as inner-sphere square-planar complexes (Au(III)(OH,Cl){sub 4}), with dominantly OH ligands at pH > 6 and mixed OH/Cl ligands at lower pH values. In combination with these spectroscopic results, Reverse Monte Carlo simulations were used to constraint the possible sorption sites on the surface of goethite. Based on this structural information, we calculated sorption isotherms of Au(III) on Fe oxy-hydroxides surfaces, using the CD-MUSIC (Charge Distribution--Multi Site Complexation) model. The various Au(III)-sorbed species were identified as a function of pH, and the results of these EXAFS+CD-MUSIC models are compared with titration experiments. The overall good agreement between the predicted and measured structural models shows the potential of this combined approach to better model sorption processes of transition elements onto highly reactive solid surfaces such as goethite and ferrihydrite.

  10. Lifetime measurements of C 17 excited states and three-body and continuum

    Office of Scientific and Technical Information (OSTI)

    effects (Journal Article) | SciTech Connect Lifetime measurements of C 17 excited states and three-body and continuum effects Citation Details In-Document Search This content will become publicly available on December 17, 2016 Title: Lifetime measurements of C 17 excited states and three-body and continuum effects Authors: Smalley, D. ; Iwasaki, H. ; Navrátil, P. ; Roth, R. ; Langhammer, J. ; Bader, V. M. ; Bazin, D. ; Berryman, J. S. ; Campbell, C. M. ; Dohet-Eraly, J. ; Fallon, P. ; Gade,

  11. A coupled transport and solid mechanics formulation with improved reaction kinetics parameters for modeling oxidation and decomposition in a uranium hydride bed.

    SciTech Connect (OSTI)

    Salloum, Maher N.; Shugard, Andrew D.; Kanouff, Michael P.; Gharagozloo, Patricia E.

    2013-03-01

    Modeling of reacting flows in porous media has become particularly important with the increased interest in hydrogen solid-storage beds. An advanced type of storage bed has been proposed that utilizes oxidation of uranium hydride to heat and decompose the hydride, releasing the hydrogen. To reduce the cost and time required to develop these systems experimentally, a valid computational model is required that simulates the reaction of uranium hydride and oxygen gas in a hydrogen storage bed using multiphysics finite element modeling. This SAND report discusses the advancements made in FY12 (since our last SAND report SAND2011-6939) to the model developed as a part of an ASC-P&EM project to address the shortcomings of the previous model. The model considers chemical reactions, heat transport, and mass transport within a hydride bed. Previously, the time-varying permeability and porosity were considered uniform. This led to discrepancies between the simulated results and experimental measurements. In this work, the effects of non-uniform changes in permeability and porosity due to phase and thermal expansion are accounted for. These expansions result in mechanical stresses that lead to bed deformation. To describe this, a simplified solid mechanics model for the local variation of permeability and porosity as a function of the local bed deformation is developed. By using this solid mechanics model, the agreement between our reacting bed model and the experimental data is improved. Additionally, more accurate uranium hydride oxidation kinetics parameters are obtained by fitting the experimental results from a pure uranium hydride oxidation measurement to the ones obtained from the coupled transport-solid mechanics model. Finally, the coupled transport-solid mechanics model governing equations and boundary conditions are summarized and recommendations are made for further development of ARIA and other Sandia codes in order for them to sufficiently implement the model.

  12. Continuum absorption in the vicinity of the toroidicity-induced Alfvén gap

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, M.; Breizman, B. N.; Zheng, L. J.; Chen, Eugene Y.

    2015-12-04

    Excitation of Alfvén modes is commonly viewed as a concern for energetic particle confinement in burning plasmas. The 3.5 MeValpha particles produced by fusion may be affected as well as other fast ions in both present and future devices. Continuum damping of such modes is one of the key factors that determine their excitation thresholds and saturation levels. This work examines the resonant dissipative response of the Alfvén continuum to an oscillating driving current when the driving frequency is slightly outside the edges of the toroidicity-induced spectral gap. The problem is largely motivated by the need to describe the continuummore » absorption in the frequency sweeping events. Akey element of this problem is the negative interference of the two closely spaced continuum crossing points.Weexplain why the lower and upper edges of the gap can have very different continuum absorption features. Lastly, the difference is associated with an eigenmode whose frequency can be arbitrarily close to the upper edge of the gap whereas the lower edge of the gap is always a finite distance away from the closest eigenmode.« less

  13. Partnering: An Engine for Innovation, Continuum Magazine, Fall 2014 / Issue 7; NREL (National Renewable Energy Laboratory)

    SciTech Connect (OSTI)

    2014-10-01

    This issue of Continuum highlights the many ways NREL partners with private industry and other research institutions. You will find references to many of the partnerships and examples of the scope of our engagement with industry leaders, government organizations, and startups.

  14. Deliberate Science, Continuum Magazine: Clean Energy Innovation at NREL, Winter 2012 (Book)

    SciTech Connect (OSTI)

    Not Available

    2012-02-01

    This quarterly magazine is dedicated to stepping beyond the technical journals to reveal NREL's vital work in a real-world context for our stakeholders. Continuum provides insights into the latest and most impactful clean energy innovations, while spotlighting those talented researchers and unique facilities that make it all happen. This edition focuses on deliberate science.

  15. Gradient Plasticity Model and its Implementation into MARMOT

    SciTech Connect (OSTI)

    Barker, Erin I.; Li, Dongsheng; Zbib, Hussein M.; Sun, Xin

    2013-08-01

    The influence of strain gradient on deformation behavior of nuclear structural materials, such as boby centered cubic (bcc) iron alloys has been investigated. We have developed and implemented a dislocation based strain gradient crystal plasticity material model. A mesoscale crystal plasticity model for inelastic deformation of metallic material, bcc steel, has been developed and implemented numerically. Continuum Dislocation Dynamics (CDD) with a novel constitutive law based on dislocation density evolution mechanisms was developed to investigate the deformation behaviors of single crystals, as well as polycrystalline materials by coupling CDD and crystal plasticity (CP). The dislocation density evolution law in this model is mechanism-based, with parameters measured from experiments or simulated with lower-length scale models, not an empirical law with parameters back-fitted from the flow curves.

  16. Studying methane migration mechanisms at Walker Ridge, Gulf of Mexico, via 3D methane hydrate reservoir modeling

    SciTech Connect (OSTI)

    Nole, Michael; Daigle, Hugh; Mohanty, Kishore; Cook, Ann; Hillman, Jess

    2015-12-15

    We have developed a 3D methane hydrate reservoir simulator to model marine methane hydrate systems. Our simulator couples highly nonlinear heat and mass transport equations and includes heterogeneous sedimentation, in-situ microbial methanogenesis, the influence of pore size contrast on solubility gradients, and the impact of salt exclusion from the hydrate phase on dissolved methane equilibrium in pore water. Using environmental parameters from Walker Ridge in the Gulf of Mexico, we first simulate hydrate formation in and around a thin, dipping, planar sand stratum surrounded by clay lithology as it is buried to 295mbsf. We find that with sufficient methane being supplied by organic methanogenesis in the clays, a 200x pore size contrast between clays and sands allows for a strong enough concentration gradient to significantly drop the concentration of methane hydrate in clays immediately surrounding a thin sand layer, a phenomenon that is observed in well log data. Building upon previous work, our simulations account for the increase in sand-clay solubility contrast with depth from about 1.6% near the top of the sediment column to 8.6% at depth, which leads to a progressive strengthening of the diffusive flux of methane with time. By including an exponentially decaying organic methanogenesis input to the clay lithology with depth, we see a decrease in the aqueous methane supplied to the clays surrounding the sand layer with time, which works to further enhance the contrast in hydrate saturation between the sand and surrounding clays. Significant diffusive methane transport is observed in a clay interval of about 11m above the sand layer and about 4m below it, which matches well log observations. The clay-sand pore size contrast alone is not enough to completely eliminate hydrate (as observed in logs), because the diffusive flux of aqueous methane due to a contrast in pore size occurs slower than the rate at which methane is supplied via organic methanogenesis. Therefore, it is likely that additional mechanisms are at play, notably bound water activity reduction in clays. Three-dimensionality allows for inclusion of lithologic heterogeneities, which focus fluid flow and subsequently allow for heterogeneity in the methane migration mechanisms that dominate in marine sediments at a local scale. Incorporating recently acquired 3D seismic data from Walker Ridge to inform the lithologic structure of our modeled reservoir, we show that even with deep adjective sourcing of methane along highly permeable pathways, local hydrate accumulations can be sourced either by diffusive or advective methane flux; advectively-sourced hydrates accumulate evenly in highly permeable strata, while diffusively-sourced hydrates are characterized by thin strata-bound intervals with high clay-sand pore size contrasts.

  17. OBSERVATIONAL STUDY OF THE CONTINUUM AND WATER MASER EMISSION IN THE IRAS 19217+1651 REGION

    SciTech Connect (OSTI)

    Rodriguez-Esnard, T.; Trinidad, M. A.; Migenes, V. E-mail: trinidad@astro.ugto.mx

    2012-12-20

    We report interferometric observations of the high-mass star-forming region IRAS 19217+1651. We observed the radio continuum (1.3 cm and 3.6 cm) and water maser emission using the Very Large Array (VLA-EVLA) in transition mode (configuration A). Two radio continuum sources were detected at both wavelengths, I19217-A and I19217-B. In addition, 17 maser spots were observed distributed mainly in two groups, M1 and M2, and one isolated maser. This latter could be indicating the relative position of another continuum source which we did not detect. The results indicate that I19217-A appears to be consistent with an ultracompact H II region associated with a zero-age main-sequence B0-type star. Furthermore, the 1.3 cm continuum emission of this source suggests a cometary morphology. In addition, I19217-B appears to be an H II region consisting of at least two stars, which may be contributing to its complex structure. It was also found that the H{sub 2}O masers of the group M1 are apparently associated with the continuum source I19217-A. These are tracing motions which are not gravitationally bound according to their spatial distribution and kinematics. They also seem to be describing outflows in the direction of the elongated cometary region. On the other hand, the second maser group, M2, could be tracing the base of a jet. Finally, infrared data from Spitzer, Midcourse Space Experiment, and IRIS show that IRAS 19217+1651 is embedded inside a large open bubble, like a broken ring, which possibly has affected the morphology of the cometary H II region observed at 1.3 cm.

  18. CONTINUUM CONTRIBUTIONS TO THE SDO/AIA PASSBANDS DURING SOLAR FLARES

    SciTech Connect (OSTI)

    Milligan, Ryan O.; McElroy, Sarah A.

    2013-11-01

    Data from the Multiple EUV Grating Spectrograph component of the Extreme-ultraviolet Variability Experiment (EVE) on board the Solar Dynamics Observatory (SDO) were used to quantify the contribution of continuum emission to each of the extreme ultraviolet (EUV) channels of the Atmospheric Imaging Assembly (AIA), also on SDO, during an X-class solar flare that occurred on 2011 February 15. Both the pre-flare-subtracted EVE spectra and fits to the associated free-free continuum were convolved with the AIA response functions of the seven EUV passbands at 10 s cadence throughout the course of the flare. It was found that 10%-25% of the total emission in the 94 , 131 , 193 , and 335 passbands throughout the main phase of the flare was due to free-free emission. Reliable measurements could not be made for the 171 channel, while the continuum contribution to the 304 channel was negligible due to the presence of the strong He II emission line. Up to 50% of the emission in the 211 channel was found to be due to free-free emission around the peak of the flare, while an additional 20% was due to the recombination continuum of He II. The analysis was extended to a number of M- and X-class flares and it was found that the level of free-free emission contributing to both the 171 and 211 passbands increased with increasing GOES class. These results suggest that the amount of continuum emission that contributes to AIA observations during flares is more significant than stated in previous studies which used synthetic, rather than observed, spectra. These findings highlight the importance of spectroscopic observations carried out in conjunction with those from imaging instruments so that the data are interpreted correctly.

  19. Analysis of fine structure in the nuclear continuum

    SciTech Connect (OSTI)

    Shevchenko, A.; Kalmykov, Y.; Neumann-Cosel, P. von; Ponomarev, V. Yu.; Richter, A.; Wambach, J.; Carter, J.; Usman, I.; Cooper, G. R. J.; Fearick, R. W.

    2008-02-15

    Fine structure has been shown to be a general phenomenon of nuclear giant resonances of different multipolarities over a wide mass range. In this article we assess various techniques that have been proposed to extract quantitative information from the fine structure in terms of characteristic scales. These include the so-called local scaling dimension, the entropy index method, Fourier analysis, and continuous and discrete wavelet transforms. As an example, results on the isoscalar giant quadrupole resonance in {sup 208}Pb from high-energy-resolution inelastic proton scattering and calculations with the quasiparticle-phonon model are analyzed. Wavelet analysis, both continuous and discrete, of the spectra is shown to be a powerful tool to extract the magnitude and localization of characteristic scales.

  20. Computational mechanics

    SciTech Connect (OSTI)

    Goudreau, G.L.

    1993-03-01

    The Computational Mechanics thrust area sponsors research into the underlying solid, structural and fluid mechanics and heat transfer necessary for the development of state-of-the-art general purpose computational software. The scale of computational capability spans office workstations, departmental computer servers, and Cray-class supercomputers. The DYNA, NIKE, and TOPAZ codes have achieved world fame through our broad collaborators program, in addition to their strong support of on-going Lawrence Livermore National Laboratory (LLNL) programs. Several technology transfer initiatives have been based on these established codes, teaming LLNL analysts and researchers with counterparts in industry, extending code capability to specific industrial interests of casting, metalforming, and automobile crash dynamics. The next-generation solid/structural mechanics code, ParaDyn, is targeted toward massively parallel computers, which will extend performance from gigaflop to teraflop power. Our work for FY-92 is described in the following eight articles: (1) Solution Strategies: New Approaches for Strongly Nonlinear Quasistatic Problems Using DYNA3D; (2) Enhanced Enforcement of Mechanical Contact: The Method of Augmented Lagrangians; (3) ParaDyn: New Generation Solid/Structural Mechanics Codes for Massively Parallel Processors; (4) Composite Damage Modeling; (5) HYDRA: A Parallel/Vector Flow Solver for Three-Dimensional, Transient, Incompressible Viscous How; (6) Development and Testing of the TRIM3D Radiation Heat Transfer Code; (7) A Methodology for Calculating the Seismic Response of Critical Structures; and (8) Reinforced Concrete Damage Modeling.

  1. ALMA results of the pseudodisk, rotating disk, and jet in the continuum and HCO{sup +} in the protostellar system HH 212

    SciTech Connect (OSTI)

    Lee, Chin-Fei; Hirano, Naomi; Shang, Hsien; Ho, Paul T. P.; Krasnopolsky, Ruben; Zhang, Qizhou

    2014-05-10

    HH 212 is a nearby (400 pc) Class 0 protostellar system showing several components that can be compared with theoretical models of core collapse. We have mapped it in the 350 GHz continuum and HCO{sup +} J = 4-3 emission with ALMA at up to ?0.''4 resolution. A flattened envelope and a compact disk are seen in the continuum around the central source, as seen before. The HCO{sup +} kinematics shows that the flattened envelope is infalling with small rotation (i.e., spiraling) into the central source, and thus can be identified as a pseudodisk in the models of magnetized core collapse. Also, the HCO{sup +} kinematics shows that the disk is rotating and can be rotationally supported. In addition, to account for the missing HCO{sup +} emission at low-redshifted velocity, an extended infalling envelope is required, with its material flowing roughly parallel to the jet axis toward the pseudodisk. This is expected if it is magnetized with an hourglass B-field morphology. We have modeled the continuum and HCO{sup +} emission of the flattened envelope and disk simultaneously. We find that a jump in density is required across the interface between the pseudodisk and the disk. A jet is seen in HCO{sup +} extending out to ?500 AU away from the central source, with the peaks upstream of those seen before in SiO. The broad velocity range and high HCO{sup +} abundance indicate that the HCO{sup +} emission traces internal shocks in the jet.

  2. Narrowband Lyman-continuum imaging of galaxies at z ? 2.85

    SciTech Connect (OSTI)

    Mostardi, R. E.; Shapley, A. E.; Nestor, D. B.; Steidel, C. C.; Trainor, R. F.; Reddy, N. A.

    2013-12-10

    We present results from a survey for z ? 2.85 Lyman-continuum (LyC) emission in the HS1549+1933 field and place constraints on the amount of ionizing radiation escaping from star-forming galaxies. Using a custom narrowband filter (NB3420) tuned to wavelengths just below the Lyman limit at z ? 2.82, we probe the LyC spectral region of 49 Lyman break galaxies (LBGs) and 91 Ly? emitters (LAEs) spectroscopically confirmed at z ? 2.82. Four LBGs and seven LAEs are detected in NB3420. Using V-band data probing the rest-frame nonionizing UV, we observe that many NB3420-detected galaxies exhibit spatial offsets between their LyC and nonionizing UV emission and are characterized by extremely blue NB3420V colors, corresponding to low ratios of nonionizing to ionizing radiation (F {sub UV}/F {sub LyC}) that are in tension with current stellar population synthesis models. We measure average values of (F {sub UV}/F {sub LyC}) for our LBG and LAE samples, correcting for foreground galaxy contamination and H I absorption in the intergalactic medium. We find (F{sub UV}/F{sub LyC}){sub corr}{sup LBG}=8245 and (F{sub UV}/F{sub LyC}){sub corr}{sup LAE}=7.43.6. These flux density ratios correspond, respectively, to relative LyC escape fractions of f{sub esc,} {sub rel}{sup LBG}=5%--8% and f{sub esc,} {sub rel}{sup LAE}=18%--49%, absolute LyC escape fractions of f{sub esc}{sup LBG}=1%--2% and f{sub esc}{sup LAE}=5%--15%, and a comoving LyC emissivity from star-forming galaxies of 8.8-15.0 10{sup 24} erg s{sup 1} Hz{sup 1} Mpc{sup 3}. In order to study the differential properties of galaxies with and without LyC detections, we analyze narrowband Ly? imaging and rest-frame near-infrared imaging, finding that while LAEs with LyC detections have lower Ly? equivalent widths on average, there is no substantial difference in the rest-frame near-infrared colors of LBGs or LAEs with and without LyC detections. These preliminary results are consistent with an orientation-dependent model where LyC emission escapes through cleared paths in a patchy interstellar medium.

  3. Electric Dipole Transitions Within The Ab initio No-Core Shell Model With

    Office of Scientific and Technical Information (OSTI)

    Continuum (Technical Report) | SciTech Connect Technical Report: Electric Dipole Transitions Within The Ab initio No-Core Shell Model With Continuum Citation Details In-Document Search Title: Electric Dipole Transitions Within The Ab initio No-Core Shell Model With Continuum Authors: Quaglioni, S ; Baroni, S ; Navratil, P Publication Date: 2012-10-01 OSTI Identifier: 1053666 Report Number(s): LLNL-TR-588973 DOE Contract Number: W-7405-ENG-48 Resource Type: Technical Report Research Org:

  4. Continuum resonance induced electromagnetic torque by a rotating plasma response to static resonant magnetic perturbation field

    SciTech Connect (OSTI)

    Liu Yueqiang; Connor, J. W.; Cowley, S. C.; Ham, C. J.; Hastie, R. J.; Hender, T. C.

    2012-10-15

    A numerical study is carried out, based on a simple toroidal tokamak equilibrium, to demonstrate the radial re-distribution of the electromagnetic torque density, as a result of a rotating resistive plasma (linear) response to a static resonant magnetic perturbation field. The computed electromagnetic torque peaks at several radial locations even in the presence of a single rational surface, due to resonances between the rotating response, in the plasma frame, and both Alfven and sound continuum waves. These peaks tend to merge together to form a rather global torque distribution, when the plasma resistivity is large. The continuum resonance induced net electromagnetic torque remains finite even in the limit of an ideal plasma.

  5. Polycyclic aromatic hydrocarbon and mid-infrared continuum emission in a z > 4 submillimeter galaxy

    SciTech Connect (OSTI)

    Riechers, Dominik A.; Pope, Alexandra; Daddi, Emanuele; Elbaz, David; Carilli, Christopher L.; Walter, Fabian; Hodge, Jacqueline; Morrison, Glenn E.; Dickinson, Mark; Dannerbauer, Helmut

    2014-05-01

    We report the detection of 6.2 μm polycyclic aromatic hydrocarbon (PAH) and rest-frame 4-7 μm continuum emission in the z = 4.055 submillimeter galaxy GN20, using the Infrared Spectrograph on board the Spitzer Space Telescope. This represents the first detection of PAH emission at z > 4. The strength of the PAH emission feature is consistent with a very high star formation rate of ∼1600 M {sub ☉} yr{sup –1}. We find that this intense starburst powers at least ∼1/3 of the faint underlying 6 μm continuum emission, with an additional, significant (and perhaps dominant) contribution due to a power-law-like hot dust source, which we interpret to likely be a faint, dust-obscured active galactic nucleus (AGN). The inferred 6 μm AGN continuum luminosity is consistent with a sensitive upper limit on the hard X-ray emission as measured by the Chandra X-Ray Observatory if the previously undetected AGN is Compton-thick. This is in agreement with the finding at optical/infrared wavelengths that the galaxy and its nucleus are heavily dust-obscured. Despite the strong power-law component enhancing the mid-infrared continuum emission, the intense starburst associated with the photon-dominated regions that give rise to the PAH emission appears to dominate the total energy output in the infrared. GN20 is one of the most luminous starburst galaxies known at any redshift, embedded in a rich protocluster of star-forming galaxies. This investigation provides an improved understanding of the energy sources that power such exceptional systems, which represent the extreme end of massive galaxy formation at early cosmic times.

  6. Fano-type coupling of a bound paramagnetic state with 2D continuum

    SciTech Connect (OSTI)

    Rozhansky, I. V.; Averkiev, N. S.; Lhderanta, E.

    2013-12-04

    We analyze an effect of a bound impurity state located at a tunnel distance from a quantum well (QW). The study is focused on the resonance case when the bound state energy lies within the continuum of the QW states. Using the developed theory we calculate spin polarization of 2D holes induced by paramagnetic (Mn) delta-layer in the vicinity of the QW and indirect exchange interaction between two impurities located at a tunnel distance from electron gas.

  7. U.S. National Committee for Rock Mechanics; and Conceptual model of fluid infiltration in fractured media. Project summary, July 28, 1997--July 27, 1998

    SciTech Connect (OSTI)

    1998-09-01

    The title describes the two tasks summarized in this report. The remainder of the report contains information on meetings held or to be held on the subjects. The US National Committee for Rock Mechanics (USNC/RM) provides for US participation in international activities in rock mechanics, principally through adherence to the International Society for Rock Mechanics (ISRM). It also keeps the US rock mechanics community informed about new programs directed toward major areas of national concern in which rock mechanics problems represent critical or limiting factors, such as energy resources, excavation, underground storage and waste disposal, and reactor siting. The committee also guides or produces advisory studies and reports on problem areas in rock mechanics. A new panel under the auspices of the US National Committee for Rock Mechanics has been appointed to conduct a study on Conceptual Models of Fluid Infiltration in Fractured Media. The study has health and environmental applications related to the underground flow of pollutants through fractured rock in and around mines and waste repositories. Support of the study has been received from the US Nuclear Regulatory Commission and the Department of Energy`s Yucca Mountain Project Office. The new study builds on the success of a recent USNC/RM report entitled Rock Fractures and Fluid Flow: Contemporary Understanding and Applications (National Academy Press, 1996, 551 pp.). A summary of the new study is provided.

  8. Continuum Magazine, Summer 2015. NREL Analysis: Reimagining What's Possible for Clean Energy (Book), NREL (National Renewable Energy Laboratory)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Continuum S U M M E R 2 0 1 5 / I S S U E 8 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. NREL.GOV/CONTINUUM NREL ANALYSIS: REIMAGINING WHAT'S POSSIBLE FOR CLEAN ENERGY 2 Continuum NREL ANALYSIS: REIMAGINING WHAT'S POSSIBLE FOR CLEAN ENERGY An objective, credible analysis capability has been part and parcel of the mission of the U.S. Department of Energy's National Renewable

  9. Computational mechanics

    SciTech Connect (OSTI)

    Raboin, P J

    1998-01-01

    The Computational Mechanics thrust area is a vital and growing facet of the Mechanical Engineering Department at Lawrence Livermore National Laboratory (LLNL). This work supports the development of computational analysis tools in the areas of structural mechanics and heat transfer. Over 75 analysts depend on thrust area-supported software running on a variety of computing platforms to meet the demands of LLNL programs. Interactions with the Department of Defense (DOD) High Performance Computing and Modernization Program and the Defense Special Weapons Agency are of special importance as they support our ParaDyn project in its development of new parallel capabilities for DYNA3D. Working with DOD customers has been invaluable to driving this technology in directions mutually beneficial to the Department of Energy. Other projects associated with the Computational Mechanics thrust area include work with the Partnership for a New Generation Vehicle (PNGV) for ''Springback Predictability'' and with the Federal Aviation Administration (FAA) for the ''Development of Methodologies for Evaluating Containment and Mitigation of Uncontained Engine Debris.'' In this report for FY-97, there are five articles detailing three code development activities and two projects that synthesized new code capabilities with new analytic research in damage/failure and biomechanics. The article this year are: (1) Energy- and Momentum-Conserving Rigid-Body Contact for NIKE3D and DYNA3D; (2) Computational Modeling of Prosthetics: A New Approach to Implant Design; (3) Characterization of Laser-Induced Mechanical Failure Damage of Optical Components; (4) Parallel Algorithm Research for Solid Mechanics Applications Using Finite Element Analysis; and (5) An Accurate One-Step Elasto-Plasticity Algorithm for Shell Elements in DYNA3D.

  10. Continuum-scale Modeling of Hydrogen and Helium Bubble Growth in Metals

    Broader source: Energy.gov [DOE]

    Presentation from the 34th Tritium Focus Group Meeting held in Idaho Falls, Idaho on September 23-25, 2014.

  11. Vehicle Technologies Office Merit Review 2015: Continuum Modeling as a Guide to Developing New Battery Materials

    Broader source: Energy.gov [DOE]

    Presentation given by Lawrence Berkley National Laboratory at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about...

  12. An Effective Continuum Model for the Gas Evolution in Internal Steam Drives

    SciTech Connect (OSTI)

    Tsimpanogiannis, Ioannis N.; Yortsos, Yanis C.

    2002-06-11

    This report examines the gas phase growth from a supersaturated, slightly compressible, liquid in a porous medium, driven by heat transfer and controlled by the application of a constant-rate decline of the system pressure.

  13. Making a Computer Model of the Most Complex System Ever Built - Continuum

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magazine | NREL photo of a man and a woman pointing to a large computer screen, which shows an advanced systems analysis of U.S. power systems with examples of high area renewables. David Mooney, director for NREL's Strategic Energy Analysis Center (left), and Robin Newmark, NREL's associate director for Energy Analysis and Decision Support (right), examine an advanced systems analysis of the impacts of high penetrations of renewable energy on the U.S. electrical grid. Photo by Dennis

  14. Coupling of Mechanical Behavior of Lithium Ion Cells to Electrochemical-Thermal Models for Battery Crush; NREL (National Renewable Energy Laboratory)

    SciTech Connect (OSTI)

    Pesaran, Ahmad; Zhang, Chao; Santhanagopalan, Shriram; Sahraei, Elham; Wierzbiki, Tom

    2015-06-15

    Propagation of failure in lithium-ion batteries during field events or under abuse is a strong function of the mechanical response of the different components in the battery. Whereas thermal and electrochemical models that capture the abuse response of batteries have been developed and matured over the years, the interaction between the mechanical behavior and the thermal response of these batteries is not very well understood. With support from the Department of Energy, NREL has made progress in coupling mechanical, thermal, and electrochemical lithium-ion models to predict the initiation and propagation of short circuits under external crush in a cell. The challenge with a cell crush simulation is to estimate the magnitude and location of the short. To address this, the model includes an explicit representation of each individual component such as the active material, current collector, separator, etc., and predicts their mechanical deformation under different crush scenarios. Initial results show reasonable agreement with experiments. In this presentation, the versatility of the approach for use with different design factors, cell formats and chemistries is explored using examples.

  15. Strong Local-Nonlocal Coupling for Integrated Fracture Modeling

    SciTech Connect (OSTI)

    Littlewood, David John; Silling, Stewart A.; Mitchell, John A.; Seleson, Pablo D.; Bond, Stephen D.; Parks, Michael L.; Turner, Daniel Z.; Burnett, Damon J.; Ostien, Jakob; Gunzburger, Max

    2015-09-01

    Peridynamics, a nonlocal extension of continuum mechanics, is unique in its ability to capture pervasive material failure. Its use in the majority of system-level analyses carried out at Sandia, however, is severely limited, due in large part to computational expense and the challenge posed by the imposition of nonlocal boundary conditions. Combined analyses in which peridynamics is em- ployed only in regions susceptible to material failure are therefore highly desirable, yet available coupling strategies have remained severely limited. This report is a summary of the Laboratory Directed Research and Development (LDRD) project "Strong Local-Nonlocal Coupling for Inte- grated Fracture Modeling," completed within the Computing and Information Sciences (CIS) In- vestment Area at Sandia National Laboratories. A number of challenges inherent to coupling local and nonlocal models are addressed. A primary result is the extension of peridynamics to facilitate a variable nonlocal length scale. This approach, termed the peridynamic partial stress, can greatly reduce the mathematical incompatibility between local and nonlocal equations through reduction of the peridynamic horizon in the vicinity of a model interface. A second result is the formulation of a blending-based coupling approach that may be applied either as the primary coupling strategy, or in combination with the peridynamic partial stress. This blending-based approach is distinct from general blending methods, such as the Arlequin approach, in that it is specific to the coupling of peridynamics and classical continuum mechanics. Facilitating the coupling of peridynamics and classical continuum mechanics has also required innovations aimed directly at peridynamic models. Specifically, the properties of peridynamic constitutive models near domain boundaries and shortcomings in available discretization strategies have been addressed. The results are a class of position-aware peridynamic constitutive laws for dramatically improved consistency at domain boundaries, and an enhancement to the meshfree discretization applied to peridynamic models that removes irregularities at the limit of the nonlocal length scale and dramatically improves conver- gence behavior. Finally, a novel approach for modeling ductile failure has been developed, moti- vated by the desire to apply coupled local-nonlocal models to a wide variety of materials, including ductile metals, which have received minimal attention in the peridynamic literature. Software im- plementation of the partial-stress coupling strategy, the position-aware peridynamic constitutive models, and the strategies for improving the convergence behavior of peridynamic models was completed within the Peridigm and Albany codes, developed at Sandia National Laboratories and made publicly available under the open-source 3-clause BSD license.

  16. Microsoft PowerPoint - turner_mwr_150_ghz_continuum_adjustment.ppt [Kompatibilitätsmodus]

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Water Vapor Continuum in Modifications to the Water Vapor Continuum in the Microwave Suggested by Ground-based 150 GHz Observations 150 GHz Observations D T 1 M i C d dd 2 Dave Turner 1 , Maria Cadeddu 2 , Ulrich Löhnert 3 , Susanne Crewell 3 , Andy Vogelmann 4 Andy Vogelmann 1 Space Science and Engineering Center, University of Wisconsin - Madison 2 Argonne National Laboratory 2 Argonne National Laboratory 3 Institute for Geophysics and Meteorology, University of Cologne 4 Brookhaven National

  17. Simulating flame lift-off characteristics of diesel and biodiesel fuels using detailed chemical-kinetic mechanisms and LES turbulence model.

    SciTech Connect (OSTI)

    Som, S; Longman, D. E.; Luo, Z; Plomer, M; Lu, T; Senecal, P.K.; Pomraning, E

    2012-01-01

    Combustion in direct-injection diesel engines occurs in a lifted, turbulent diffusion flame mode. Numerous studies indicate that the combustion and emissions in such engines are strongly influenced by the lifted flame characteristics, which are in turn determined by fuel and air mixing in the upstream region of the lifted flame, and consequently by the liquid breakup and spray development processes. From a numerical standpoint, these spray combustion processes depend heavily on the choice of underlying spray, combustion, and turbulence models. The present numerical study investigates the influence of different chemical kinetic mechanisms for diesel and biodiesel fuels, as well as Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) turbulence models on predicting flame lift-off lengths (LOLs) and ignition delays. Specifically, two chemical kinetic mechanisms for n-heptane (NHPT) and three for biodiesel surrogates are investigated. In addition, the RNG k-{epsilon} (RANS) model is compared to the Smagorinsky based LES turbulence model. Using adaptive grid resolution, minimum grid sizes of 250 {micro}m and 125 {micro}m were obtained for the RANS and LES cases respectively. Validations of these models were performed against experimental data from Sandia National Laboratories in a constant volume combustion chamber. Ignition delay and flame lift-off validations were performed at different ambient temperature conditions. The LES model predicts lower ignition delays and qualitatively better flame structures compared to the RNG k-{epsilon} model. The use of realistic chemistry and a ternary surrogate mixture, which consists of methyl decanoate, methyl 9-decenoate, and NHPT, results in better predicted LOLs and ignition delays. For diesel fuel though, only marginal improvements are observed by using larger size mechanisms. However, these improved predictions come at a significant increase in computational cost.

  18. Hierarchical Models for Batteries: Overview with Some Case Studies

    SciTech Connect (OSTI)

    Pannala, Sreekanth; Mukherjee, Partha P; Allu, Srikanth; Nanda, Jagjit; Martha, Surendra K; Dudney, Nancy J; Turner, John A

    2012-01-01

    Batteries are complex multiscale systems and a hierarchy of models has been employed to study different aspects of batteries at different resolutions. For the electrochemistry and charge transport, the models span from electric circuits, single-particle, pseudo 2D, detailed 3D, and microstructure resolved at the continuum scales and various techniques such as molecular dynamics and density functional theory to resolve the atomistic structure. Similar analogies exist for the thermal, mechanical, and electrical aspects of the batteries. We have been recently working on the development of a unified formulation for the continuum scales across the electrode-electrolyte-electrode system - using a rigorous volume averaging approach typical of multiphase formulation. This formulation accounts for any spatio-temporal variation of the different properties such as electrode/void volume fractions and anisotropic conductivities. In this talk the following will be presented: The background and the hierarchy of models that need to be integrated into a battery modeling framework to carry out predictive simulations, Our recent work on the unified 3D formulation addressing the missing links in the multiscale description of the batteries, Our work on microstructure resolved simulations for diffusion processes, Upscaling of quantities of interest to construct closures for the 3D continuum description, Sample results for a standard Carbon/Spinel cell will be presented and compared to experimental data, Finally, the infrastructure we are building to bring together components with different physics operating at different resolution will be presented. The presentation will also include details about how this generalized approach can be applied to other electrochemical storage systems such as supercapacitors, Li-Air batteries, and Lithium batteries with 3D architectures.

  19. System-Level Heat Transfer Analysis, Thermal- Mechanical Cyclic Stress Analysis, and Environmental Fatigue Modeling of a Two-Loop Pressurized Water Reactor. A Preliminary Study

    SciTech Connect (OSTI)

    Mohanty, Subhasish; Soppet, William; Majumdar, Saurin; Natesan, Ken

    2015-01-03

    This report provides an update on an assessment of environmentally assisted fatigue for light water reactor components under extended service conditions. This report is a deliverable in April 2015 under the work package for environmentally assisted fatigue under DOE's Light Water Reactor Sustainability program. In this report, updates are discussed related to a system level preliminary finite element model of a two-loop pressurized water reactor (PWR). Based on this model, system-level heat transfer analysis and subsequent thermal-mechanical stress analysis were performed for typical design-basis thermal-mechanical fatigue cycles. The in-air fatigue lives of components, such as the hot and cold legs, were estimated on the basis of stress analysis results, ASME in-air fatigue life estimation criteria, and fatigue design curves. Furthermore, environmental correction factors and associated PWR environment fatigue lives for the hot and cold legs were estimated by using estimated stress and strain histories and the approach described in NUREG-6909. The discussed models and results are very preliminary. Further advancement of the discussed model is required for more accurate life prediction of reactor components. This report only presents the work related to finite element modelling activities. However, in between multiple tensile and fatigue tests were conducted. The related experimental results will be presented in the year-end report.

  20. Intrinsic dissipation in a nano-mechanical resonator

    SciTech Connect (OSTI)

    Kunal, K.; Aluru, N. R.

    2014-09-07

    We investigate the effect of size on intrinsic dissipation in nano-structures. We use molecular dynamics simulation and study dissipation under two different modes of deformation: stretching and bending mode. In the case of stretching deformation (with uniform strain field), dissipation takes place due to Akhiezer mechanism. For bending deformation, in addition to the Akhiezer mechanism, the spatial temperature gradient also plays a role in the process of entropy generation. Interestingly, we find that the bending modes have a higher Q factor in comparison with the stretching deformation (under the same frequency of operation). Furthermore, with the decrease in size, the difference in Q factor between the bending and stretching deformation becomes more pronounced. The lower dissipation for the case of bending deformation is explained to be due to the surface scattering of phonons. A simple model, for phonon dynamics under an oscillating strain field, is considered to explain the observed variation in dissipation rate. We also studied the scaling of Q factor with initial tension, in a beam under flexure. We develop a continuum theory to explain the observed results.

  1. Application of the multi-mechanism deformation model for three-dimensional simulations of salt : behavior for the strategic petroleum reserve.

    SciTech Connect (OSTI)

    Ehgartner, Brian L.; Sobolik, Steven Ronald; Bean, James E.

    2010-07-01

    The U.S. Strategic Petroleum Reserve stores crude oil in 62 solution-mined caverns in salt domes located in Texas and Louisiana. Historically, three-dimensional geomechanical simulations of the behavior of the caverns have been performed using a power law creep model. Using this method, and calibrating the creep coefficient to field data such as cavern closure and surface subsidence, has produced varying degrees of agreement with observed phenomena. However, as new salt dome locations are considered for oil storage facilities, pre-construction geomechanical analyses are required that need site-specific parameters developed from laboratory data obtained from core samples. The multi-mechanism deformation (M-D) model is a rigorous mathematical description of both transient and steady-state creep phenomena. Recent enhancements to the numerical integration algorithm within the model have created a more numerically stable implementation of the M-D model. This report presents computational analyses to compare the results of predictions of the geomechanical behavior at the West Hackberry SPR site using both models. The recently-published results using the power law creep model produced excellent agreement with an extensive set of field data. The M-D model results show similar agreement using parameters developed directly from laboratory data. It is also used to predict the behavior for the construction and operation of oil storage caverns at a new site, to identify potential problems before a final cavern layout is designed.

  2. Antideuteron production in {upsilon}(nS) decays and the nearby continuum

    SciTech Connect (OSTI)

    Asner, D. M.; Edwards, K. W.; Briere, R. A.; Chen, J.; Ferguson, T.; Tatishvili, G.; Vogel, H.; Watkins, M. E.; Rosner, J. L.; Adam, N. E.; Alexander, J. P.; Berkelman, K.; Cassel, D. G.; Duboscq, J. E.; Ecklund, K. M.; Ehrlich, R.; Fields, L.; Galik, R. S.; Gibbons, L.; Gray, R.

    2007-01-01

    Using CLEO data, we study the production of the antideuteron, d, in {upsilon}(nS) resonance decays and the nearby continuum. The branching ratios obtained are B{sup dir}({upsilon}(1S){yields}dX)=(3.36{+-}0.23{+-}0.25)x10{sup -5}, B({upsilon}(1S){yields}dX)=(2.86{+-}0.19{+-}0.21)x10{sup -5}, and B({upsilon}(2S){yields}dX)=(3.37{+-}0.50{+-}0.25)x10{sup -5}, where the 'dir' superscript indicates that decays produced via reannihilation of the bb pair to a {gamma}* are removed from both the signal and the normalizing number of {upsilon}(1S) decays in order to isolate direct decays of the {upsilon}(1S) to ggg, gg{gamma}. Upper limits at 90% C.L. are given for B({upsilon}(4S){yields}dX)<1.3x10{sup -5}, and continuum production {sigma}(e{sup +}e{sup -}{yields}dX)<0.031 pb. The {upsilon}(2S) data is also used to extract a limit on {chi}{sub bJ}{yields}dX. The results indicate enhanced deuteron production in ggg, gg{gamma} hadronization compared to {gamma}*{yields}qq. Baryon number compensation is also investigated with the large {upsilon}(1S){yields}dX sample.

  3. Computational Structural Mechanics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    load-2 TRACC RESEARCH Computational Fluid Dynamics Computational Structural Mechanics Transportation Systems Modeling Computational Structural Mechanics Overview of CSM Computational structural mechanics is a well-established methodology for the design and analysis of many components and structures found in the transportation field. Modern finite-element models (FEMs) play a major role in these evaluations, and sophisticated software, such as the commercially available LS-DYNA® code, is

  4. Solvent Extraction of Sodium Hydroxide Using Alkylphenols and Fluorinated Alcohols: Understanding the Extraction Mechanism by Equilibrium Modeling

    SciTech Connect (OSTI)

    Kang, Hyun-Ah; Engle, Nancy L.; Bonnesen Peter V.; Delmau, Laetitia H.; Haverlock, Tamara J.; Moyer, Bruce A.

    2004-03-29

    In the present work, it has been the aim to examine extraction efficiencies of nine proton-ionizable alcohols (HAs) in 1-octanol and to identify both the controlling equilibria and predominant species involved in the extraction process within a thermochemical model. Distribution ratios for sodium (DNa) extraction were measured as a function of organic-phase HA and aqueous-phase NaOH molarity at 25 C. Extraction efficiency follows the expected order of acidity of the HAs, 4-(tert-octyl) phenol (HA 1a) and 4-noctyl- a,a-bis-(trifluoromethyl)benzyl alcohol (HA 2a) being the most efficient extractants among the compounds tested. By use of the equilibrium-modeling program SXLSQI, a model for the extraction of NaOH has been advanced based on an ion-pair extraction by the diluent to give organic-phase Na+OH- and corresponding free ions and cation exchange by the weak acids to form monomeric organic-phase Na+A- and corresponding free organic-phase ions.

  5. VERY BLUE UV-CONTINUUM SLOPE {beta} OF LOW LUMINOSITY z {approx} 7 GALAXIES FROM WFC3/IR: EVIDENCE FOR EXTREMELY LOW METALLICITIES?

    SciTech Connect (OSTI)

    Bouwens, R. J.; Illingworth, G. D.; Magee, D.; Trenti, M.; Stiavelli, M.; Franx, M.; Van Dokkum, P. G.; Labbe, I.

    2010-01-10

    We use the ultra-deep WFC3/IR data over the Hubble Ultra Deep Field and the Early Release Science WFC3/IR data over the CDF-South GOODS field to quantify the broadband spectral properties of candidate star-forming galaxies at z {approx} 7. We determine the UV-continuum slope {beta} in these galaxies, and compare the slopes with galaxies at later times to measure the evolution in {beta}. For luminous L* {sub z=3} galaxies, we measure a mean UV-continuum slope {beta} of -2.0 {+-} 0.2, which is comparable to the {beta} {approx} -2 derived at similar luminosities at z {approx} 5-6. However, for the lower luminosity 0.1L* {sub z=3} galaxies, we measure a mean {beta} of -3.0 {+-} 0.2. This is substantially bluer than is found for similar luminosity galaxies at z {approx} 4, just 800 Myr later, and even at z {approx} 5-6. In principle, the observed {beta} of -3.0 can be matched by a very young, dust-free stellar population, but when nebular emission is included the expected {beta} becomes {>=}-2.7. To produce these very blue {beta}s (i.e., {beta} {approx} -3), extremely low metallicities and mechanisms to reduce the red nebular emission seem to be required. For example, a large escape fraction (i.e., f {sub esc} {approx}> 0.3) could minimize the contribution from this red nebular emission. If this is correct and the escape fraction in faint z {approx} 7 galaxies is {approx}>0.3, it may help to explain how galaxies reionize the universe.

  6. Partnering: An Engine for Innovation: Continuum Magazine, Fall 2014/Issue 7 (Book), NREL (National Renewable Energy Laboratory)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    L L 2 0 1 4 / I S S U E 7 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. WWW.NREL.GOV/CONTINUUM P A R T N E R I N G : A N E N G I N E F O R I N N O V A T I O N 2 Continuum DAN SAYS PARTNERING: AN ENGINE FOR INNOVATION Collaborative research truly is an engine for innovation. While the term "partnership" may seem straightforward, there are actually many ways in which

  7. Parabolic sturmians approach to the three-body continuum Coulomb problem

    SciTech Connect (OSTI)

    Zaytsev, S. A.; Popov, Yu. V.; Piraux, B.

    2013-03-15

    The three-body continuum Coulomb problem is treated in terms of the generalized parabolic coordinates. Approximate solutions are expressed in the form of a Lippmann-Schwinger-type equation, where the Green's function includes the leading term of the kinetic energy and the total potential energy, whereas the potential contains the non-orthogonal part of the kinetic energy operator. As a test of this approach, the integral equation for the (e{sup -}, e{sup -}, He{sup ++}) system has been solved numerically by using the parabolic Sturmian basis representation of the (approximate) potential. Convergence of the expansion coefficients of the solution has been obtained as the basis set used to describe the potential is enlarged.

  8. Energy Saving Homes and Buildings, Continuum Magazine, Spring 2014 / Issue 6 (Book)

    SciTech Connect (OSTI)

    Not Available

    2014-03-01

    This issue of Continuum focuses on NREL's research to improve the energy efficiency of residential and commercial buildings. Heating, cooling, and lighting our homes and commercial structures account for more than 70% of all electricity used in the United States. That costs homeowners, businesses, and government agencies more than $400 billion annually, about 40% of our nation's total energy costs. Producing that energy contributes almost 40% of our nation's carbon dioxide emissions.By 2030, an estimated 900 billion square feet of new and rebuilt construction will be developed worldwide, providing an unprecedented opportunity to create efficient, sustainable buildings. Increasing the energy performance of our homes alone could potentially eliminate up to 160 million tons of greenhouse gas emissions and lower residential energy bills by $21 billion annually by the end of the decade.

  9. Bridging a gap between continuum-QCD and ab initio predictions of hadron observables

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Binosi, Daniele; Chang, Lei; Papavassiliou, Joannis; Roberts, Craig D.

    2015-01-23

    Within contemporary hadron physics there are two common methods for determining the momentum-dependence of the interaction between quarks: the top-down approach, which works toward an ab initio computation of the interaction via direct analysis of the gauge-sector gap equations; and the bottom-up scheme, which aims to infer the interaction by fitting data within a well-defined truncation of those equations in the matter sector that are relevant to bound-state properties. We unite these two approaches by demonstrating that the renormalisation-group-invariant running-interaction predicted by contemporary analyses of QCDs gauge sector coincides with that required in order to describe ground-state hadron observables usingmorea nonperturbative truncation of QCDs DysonSchwinger equations in the matter sector. This bridges a gap that had lain between nonperturbative continuum-QCD and the ab initio prediction of bound-state properties.less

  10. Spectroscopic investigation of the vibrational quasi-continuum arising from internal rotation of a methyl group

    SciTech Connect (OSTI)

    Hougen, J.T.

    1993-12-01

    The goal of this project is to use spectroscopic techniques to investigate in detail phenomena involving the vibrational quasi-continuum in a simple physical system. Acetaldehyde was chosen for the study because: (i) methyl groups have been suggested to be important promotors of intramolecular vibrational relaxation, (ii) the internal rotation of a methyl group is an easily describle large-amplitude motion, which should retain its simple character even at high levels of excitation, and (iii) the aldehyde carbonyl group offers the possibility of both vibrational and electronic probing. The present investigation of the ground electronic state has three parts: (1) understanding the {open_quotes}isolated{close_quotes} internal-rotation motion below, at, and above the top of the torsional barrier, (2) understanding in detail traditional (bond stretching and bending) vibrational fundamental and overtone states, and (3) understanding interactions involving states with multiquantum excitations of at least one of these two kinds of motion.

  11. Thermo-mechanical and neutron lifetime modeling and design of Be pebbles in the neutron multiplier for the LIFE engine

    SciTech Connect (OSTI)

    DeMange, P; Marian, J; de Caro, M S; Caro, A

    2009-03-16

    Concept designs for the laser-initiated fusion/fission engine (LIFE) include a neutron multiplication blanket containing Be pebbles flowing in a molten salt coolant. These pebbles must be designed to withstand the extreme irradiation and temperature conditions in the blanket to enable a safe and cost-effective operation of LIFE. In this work, we develop design criteria for spherical Be pebbles on the basis of their thermomechanical behavior under continued neutron exposure. We consider the effects of high fluence/fast flux on the elastic, thermal and mechanical properties of nuclear-grade Be. Our results suggest a maximum pebble diameter of 30 mm to avoid tensile failure, coated with an anti-corrosive, high-strength metallic shell to avoid failure by pebble contact. Moreover, we find that the operation temperature must always be kept above 450 C to enable creep to relax the stresses induced by swelling, which we estimate to be at least 16 months if uncoated and up to six years when coated. We identify the sources of uncertainty on the properties used and discuss the advantages of new intermetallic beryllides and their use in LIFE's neutron multiplier. To establish Be-pebble lifetimes with improved confidence, reliable experiments to measure irradiation creep must be performed.

  12. Addressing the Recalcitrance of Cellulose Degradation through Cellulase Discovery, Nano-scale Elucidation of Molecular Mechanisms, and Kinetic Modeling

    SciTech Connect (OSTI)

    Walker, Larry P., Bergstrom, Gary; Corgie, Stephane; Craighead, Harold; Gibson, Donna; Wilson, David

    2011-06-13

    This research project was designed to play a vital role in the development of low cost sugars from cellulosic biomass and contributing to the national effort to displace fossil fuel usage in the USA transportation sector. The goal was to expand the portfolio of cell wall degrading enzymes through innovative research at the nano-scale level, prospecting for novel cellulases and building a kinetic framework for the development of more effective enzymatic conversion processes. More precisely, the goal was to elucidate the molecular mechanisms for some cellulases that are very familiar to members of our research team and to investigate what we hope are novel cellulases or new enzyme combinations from the world of plant pathogenic fungi and bacteria. Hydrolytic activities of various cellulases and cellulase cocktails were monitored at the nanoscale of cellulose fibrils and the microscale of pretreated cellulose particles, and we integrated this insight into a heterogeneous reaction framework. The over-riding approach for this research program was the application of innovative and cutting edge optical and high-throughput screening and analysis techniques for observing how cellulases hydrolyze real substrates.

  13. Efficient Reformulation of Solid Phase Diffusion in Electrochemical-Mechanical Coupled Models for Lithium-Ion Batteries: Effect of Intercalation Induced Stresses

    SciTech Connect (OSTI)

    De, S; Suthar, B; Rife, D; Sikha, G; Subramanian, VR

    2013-07-23

    Lithium-ion batteries are typically modeled using porous electrode theory coupled with various transport and reaction mechanisms with an appropriate discretization or approximation for the solid phase diffusion within the electrode particle. One of the major difficulties in simulating Li-ion battery models is the need for simulating solid-phase diffusion in the second radial dimension r within the particle. It increases the complexity of the model as well as the computation time/cost to a great extent. This is Particularly true for the inclusion of pressure induced diffusion inside particles experiencing volume change. A computationally efficient representation for solid-phase diffusion is discussed in this paper. The operating condition has a significant effect on the validity, accuracy, and efficiency of various approximations for the solid-phase transport governed by pressure induced diffusion. This paper introduces efficient methods for solid phase reformulation - (1) parabolic profile approach and (2) a mixed order finite difference method for approximating/representing solid-phase concentration variations within the active materials of porous electrodes for macroscopic models for lithium-ion batteries. (C) 2013 The Electrochemical Society. All rights reserved.

  14. Integrated Experimental and Modeling Studies of Mineral Carbonation as a Mechanism for Permanent Carbon Sequestration in Mafic/Ultramafic Rocks

    SciTech Connect (OSTI)

    Wang, Zhengrong; Qiu, Lin; Zhang, Shuang; Bolton, Edward; Bercovici, David; Ague, Jay; Karato, Shun-Ichiro; Oristaglio, Michael; Zhu, Wen-Iu; Lisabeth, Harry; Johnson, Kevin

    2014-09-30

    A program of laboratory experiments, modeling and fieldwork was carried out at Yale University, University of Maryland, and University of Hawaii, under a DOE Award (DE-FE0004375) to study mineral carbonation as a practical method of geologic carbon sequestration. Mineral carbonation, also called carbon mineralization, is the conversion of (fluid) carbon dioxide into (solid) carbonate minerals in rocks, by way of naturally occurring chemical reactions. Mafic and ultramafic rocks, such as volcanic basalt, are natural candidates for carbonation, because the magnesium and iron silicate minerals in these rocks react with brines of dissolved carbon dioxide to form carbonate minerals. By trapping carbon dioxide (CO2) underground as a constituent of solid rock, carbonation of natural basalt formations would be a secure method of sequestering CO2 captured at power plants in efforts to mitigate climate change. Geochemical laboratory experiments at Yale, carried out in a batch reactor at 200C and 150 bar (15 MPa), studied carbonation of the olivine mineral forsterite (Mg2SiO4) reacting with CO2 brines in the form of sodium bicarbonate (NaHCO3) solutions. The main carbonation product in these reactions is the carbonate mineral magnesite (MgCO3). A series of 32 runs varied the reaction time, the reactive surface area of olivine grains and powders, the concentration of the reacting fluid, and the starting ratio of fluid to olivine mass. These experiments were the first to study the rate of olivine carbonation under passive conditions approaching equilibrium. The results show that, in a simple batch reaction, olivine carbonation is fastest during the first 24 hours and then slows significantly and even reverses. A natural measure of the extent of carbonation is a quantity called the carbonation fraction, which compares the amount of carbon removed from solution, during a run, to the maximum amount that could have been removed if the olivine initially present had fully dissolved and the cations released had subsequently precipitated in carbonate minerals. The carbonation fractions observed in batch experiments with olivine grains and powders varied significantly, from less than 0.01 (1%) to more than 0.5 (50%). Over time, the carbonation fractions reached an upper limit after about 24 to 72 hours of reaction, then stayed constant or decreased. The peak Final Scientific/Technical Report DE-FE0004275 | Mineral Carbonation | 4 coincided with the appearance of secondary magnesium-bearing silicate minerals, whose formation competes for magnesium ions in solution and can even promote conditions that dissolve magnesite. The highest carbonation fractions resulted from experiments with low ratios of concentrated solution to olivine, during which amorphous silica spheres or meshes formed, instead of secondary silicate minerals. The highest carbonation fractions appear to result from competing effects. Precipitation of silica layers on olivine reduces the reactive surface area and, thus, the rate of olivine dissolution (which ultimately limits the carbonation rate), but these same silica layers can also inhibit the formation of secondary silicate minerals that consume magnesite formed in earlier stages of carbonation. Simulation of these experiments with simple geochemical models using the software program EQ3/6 reproduces the general trends observedespecially the results for the carbonation fraction in short-run experiments. Although further experimentation and better models are needed, this study nevertheless provides a framework for understanding the optimal conditions for sequestering carbon dioxide by reacting CO2-bearing fluids with rocks containing olivine minerals. A series of experiments at the Rock Physics Laboratory at the University of Maryland studied the carbonation process during deformation of thermally cracked olivine-rich rock samples (dunit

  15. Utility-Scale Future, Continuum Magazine: Clean Energy Innovation at NREL, Spring 2011, Issue 1 Vol. 1

    SciTech Connect (OSTI)

    Not Available

    2011-08-01

    This quarterly magazine is dedicated to stepping beyond the technical journals to reveal NREL's vital work in a real-world context for our stakeholders. Continuum provides insights into the latest and most impactful clean energy innovations, while spotlighting those talented researchers and unique facilities that make it all happen. This edition focuses on creating a utility-scale future.

  16. Creating physically-based three-dimensional microstructures: Bridging phase-field and crystal plasticity models.

    SciTech Connect (OSTI)

    Lim, Hojun; Owen, Steven J.; Abdeljawad, Fadi F.; Hanks, Byron; Battaile, Corbett Chandler

    2015-09-01

    In order to better incorporate microstructures in continuum scale models, we use a novel finite element (FE) meshing technique to generate three-dimensional polycrystalline aggregates from a phase field grain growth model of grain microstructures. The proposed meshing technique creates hexahedral FE meshes that capture smooth interfaces between adjacent grains. Three dimensional realizations of grain microstructures from the phase field model are used in crystal plasticity-finite element (CP-FE) simulations of polycrystalline a -iron. We show that the interface conformal meshes significantly reduce artificial stress localizations in voxelated meshes that exhibit the so-called "wedding cake" interfaces. This framework provides a direct link between two mesoscale models - phase field and crystal plasticity - and for the first time allows mechanics simulations of polycrystalline materials using three-dimensional hexahedral finite element meshes with realistic topological features.

  17. Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    SciTech Connect (OSTI)

    Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi; Bakule, Pavel; Yokoyama, Koji; Ishida, Katsuhiko; Iwasaki, Masahiko

    2011-09-15

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

  18. A CONTINUUM OF PLANET FORMATION BETWEEN 1 AND 4 EARTH RADII

    SciTech Connect (OSTI)

    Schlaufman, Kevin C.

    2015-02-01

    It has long been known that stars with high metallicity are more likely to host giant planets than stars with low metallicity. Yet the connection between host star metallicity and the properties of small planets is only just beginning to be investigated. It has recently been argued that the metallicity distribution of stars with exoplanet candidates identified by Kepler provides evidence for three distinct clusters of exoplanets, distinguished by planet radius boundaries at 1.7 R{sub ?} and 3.9 R{sub ?}. This would suggest that there are three distinct planet formation pathways for super-Earths, mini-Neptunes, and giant planets. However, as I show through three independent analyses, there is actually no evidence for the proposed radius boundary at 1.7 R{sub ?}. On the other hand, a more rigorous calculation demonstrates that a single, continuous relationship between planet radius and metallicity is a better fit to the data. The planet radius and metallicity data therefore provides no evidence for distinct categories of small planets. This suggests that the planet formation process in a typical protoplanetary disk produces a continuum of planet sizes between 1 R{sub ?} and 4 R{sub ?}. As a result, the currently available planet radius and metallicity data for solar-metallicity F and G stars give no reason to expect that the amount of solid material in a protoplanetary disk determines whether super-Earths or mini-Neptunes are formed.

  19. Pore and Continuum Scale Study of the Effect of Subgrid Transport Heterogeneity on Redox Reaction Rates

    SciTech Connect (OSTI)

    Liu, Yuanyuan; Liu, Chongxuan; Zhang, Changyong; Yang, Xiaofan; Zachara, John M.

    2015-08-01

    A micromodel system with a pore structure for heterogeneous flow and transport was used to investigate the effect of subgrid transport heterogeneity on redox reaction rates. Hematite reductive dissolution by injecting a reduced form of flavin mononucleotide (FMNH2) at variable flow rates was used as an example to probe the variations of redox reaction rates in different subgrid transport domains. Experiments, pore-scale simulations, and macroscopic modeling were performed to measure and simulate in-situ hematite reduction and to evaluate the scaling behavior of the redox reaction rates from the pore to macroscopic scales. The results indicated that the measured pore-scale rates of hematite reduction were consistent with the predictions from a pore scale reactive transport model. A general trend is that hematite reduction followed reductant transport pathways, starting from the advection-dominated pores toward the interior of diffusion-dominated domains. Two types of diffusion domains were considered in the micromodel: a micropore diffusion domain, which locates inside solid grains or aggregates where reactant transport is limited by diffusion; and a macropore diffusion domain, which locates at wedged, dead-end pore spaces created by the grain-grain contacts. The rate of hematite reduction in the advection-dominated domain was faster than those in the diffusion-controlled domains, and the rate in the macropore diffusion domain was faster than that in the micropore domain. The reduction rates in the advection and macropore diffusion domains increased with increasing flow rate, but were affected by different mechanisms. The rate increase in the advection domain was controlled by the mass action effect as a faster flow supplied more reactants, and the rate increase in the macropore domain was more affected by the rate of mass exchange with the advection domain, which increased with increasing flow rate. The hematite reduction rate in the micropore domain was, however, not affected by the flow rate because molecular diffusion limits reductant supply to the micropore domain interior. Domain-based macroscopic models were evaluated to scale redox reaction rates from the pore to macroscopic scales. A single domain model, which ignores subgrid transport heterogeneity deviated significantly from the pore-scale results. Further analysis revealed that the rate expression for hematite reduction was not scalable from the pore to porous media using the single domain model. A three-domain model, which effectively considers subgrid reactive diffusion in the micropore and macropore domains, significantly improved model description. Overall this study revealed the importance of subgrid transport heterogeneity in the manifestation of redox reaction rates in porous media and in scaling reactions from the pore to porous media. The research also supported that the domain-based scaling approach can be used to directly scale redox reactions in porous media with subgrid transport heterogeneity.

  20. Conservation Laws for Coupled Hydro-mechanical Processes in Unsaturated Porous Media: Theory and Implementation

    SciTech Connect (OSTI)

    Borja, R I; White, J A

    2010-02-19

    We develop conservation laws for coupled hydro-mechanical processes in unsaturated porous media using three-phase continuum mixture theory. From the first law of thermodynamics, we identify energy-conjugate variables for constitutive modeling at macroscopic scale. Energy conjugate expressions identified relate a certain measure of effective stress to the deformation of the solid matrix, the degree of saturation to the matrix suction, the pressure in each constituent phase to the corresponding intrinsic volume change of this phase, and the seepage forces to the corresponding pressure gradients. We then develop strong and weak forms of boundary-value problems relevant for 3D finite element modeling of coupled hydro-mechanical processes in unsaturated porous media. The paper highlights a 3D numerical example illustrating the advances in the solution of large-scale coupled finite element systems, as well as the challenges in developing more predictive tools satisfying the basic conservation laws and the observed constitutive responses for unsaturated porous materials.

  1. Structural model of the circadian clock KaiB?KaiC complex and mechanism for modulation of KaiC phosphorylation

    SciTech Connect (OSTI)

    Pattanayek, Rekha; Williams, Dewight R.; Pattanayek, Sabuj; Mori, Tetsuya; Johnson, Carl H.; Stewart, Phoebe L.; Egli, Martin

    2010-03-08

    The circadian clock of the cyanobacterium Synechococcus elongatus can be reconstituted in vitro by the KaiA, KaiB and KaiC proteins in the presence of ATP. The principal clock component, KaiC, undergoes regular cycles between hyper- and hypo-phosphorylated states with a period of ca. 24 h that is temperature compensated. KaiA enhances KaiC phosphorylation and this enhancement is antagonized by KaiB. Throughout the cycle Kai proteins interact in a dynamic manner to form complexes of different composition. We present a three-dimensional model of the S. elongatus KaiB-KaiC complex based on X-ray crystallography, negative-stain and cryo-electron microscopy, native gel electrophoresis and modelling techniques. We provide experimental evidence that KaiB dimers interact with KaiC from the same side as KaiA and for a conformational rearrangement of the C-terminal regions of KaiC subunits. The enlarged central channel and thus KaiC subunit separation in the C-terminal ring of the hexamer is consistent with KaiC subunit exchange during the dephosphorylation phase. The proposed binding mode of KaiB explains the observation of simultaneous binding of KaiA and KaiB to KaiC, and provides insight into the mechanism of KaiB's antagonism of KaiA.

  2. Sandia National Laboratories: Careers: Mechanical Engineering

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    at Sandia Applied mechanics Modeling and simulation Conceptual and mechanical design definition Material selection and fabrication oversight Stress, dynamic, and thermal analysis...

  3. Multiscale Modeling of Grain Boundary Segregation and Embrittlement in Tungsten for Mechanistic Design of Alloys for Coal Fired Plants

    SciTech Connect (OSTI)

    Luo, Jian; Tomar, Vikas; Zhou, Naixie; Lee, Hongsuk

    2013-06-30

    Based on a recent discovery of premelting-like grain boundary segregation in refractory metals occurring at high temperatures and/or high alloying levels, this project investigated grain boundary segregation and embrittlement in tungsten (W) based alloys. Specifically, new interfacial thermodynamic models have been developed and quantified to predict high-temperature grain boundary segregation in the W-Ni binary alloy and W-Ni-Fe, W-Ni-Ti, W-Ni-Co, W-Ni-Cr, W-Ni-Zr and W-Ni-Nb ternary alloys. The thermodynamic modeling results have been experimentally validated for selected systems. Furthermore, multiscale modeling has been conducted at continuum, atomistic and quantum-mechanical levels to link grain boundary segregation with embrittlement. In summary, this 3-year project has successfully developed a theoretical framework in combination with a multiscale modeling strategy for predicting grain boundary segregation and embrittlement in W based alloys.

  4. Development of a Mechanistic-Based Healing Model for Self-Healing Glass Seals

    SciTech Connect (OSTI)

    Xu, Wei; Stephens, Elizabeth V.; Sun, Xin; Khaleel, Mohammad A.; Zbib, Hussein M.

    2012-10-01

    Self-healing glass, a recent development of hermetic sealant materials, has the ability to effectively repair damage when heated to elevated temperatures; thus, able to extend its service life. Since crack healing morphological changes in the glass material are usually temperature and stress dependent, quantitative studies to determine the effects of thermo-mechanical conditions on the healing behavior of the self-healing glass sealants are extremely useful to accommodate the design and optimization of the sealing systems within SOFCs. The goal of this task is to develop a mechanistic-based healing model to quantify the stress and temperature dependent healing behavior. A two-step healing mechanism was developed and implemented into finite element (FE) models through user-subroutines. Integrated experimental/kinetic Monte Carlo (kMC) simulation methodology was taken to calibrate the model parameters. The crack healing model is able to investigate the effects of various thermo-mechanical factors; therefore, able to determine the critical conditions under which the healing mechanism will be activated. Furthermore, the predicted results can be used to formulate the continuum damage-healing model and to assist the SOFC stack level simulations in predicting and evaluating the effectiveness and the performance of various engineering seal designs.

  5. Mechanical memory

    DOE Patents [OSTI]

    Gilkey, Jeffrey C.; Duesterhaus, Michelle A.; Peter, Frank J.; Renn, Rosemarie A.; Baker, Michael S.

    2006-08-15

    A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

  6. Mechanical memory

    DOE Patents [OSTI]

    Gilkey, Jeffrey C.; Duesterhaus, Michelle A.; Peter, Frank J.; Renn, Rosemarie A.; Baker, Michael S.

    2006-05-16

    A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

  7. Agreement Mechanisms

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Agreement Mechanisms Agreement Mechanisms World-class experts and capabilities countering all aspects of explosive threats, and aiming predominantly at enhanced detection capabilities. CRADA: Cooperative Research and Development Agreement What is it? Work performed in collaboration with a sponsor. What does it do? Enables Los Alamos staff to participate with industry, academia, and nonprofit entities on collaborative R&D activities of mutual benefit. When is it used? An organization's

  8. A 3D Orthotropic Strain-Rate Dependent Elastic Damage Material Model.

    SciTech Connect (OSTI)

    English, Shawn Allen

    2014-09-01

    A three dimensional orthotropic elastic constitutive model with continuum damage and cohesive based fracture is implemented for a general polymer matrix composite lamina. The formulation assumes the possibility of distributed (continuum) damage followed b y localized damage. The current damage activation functions are simply partially interactive quadratic strain criteria . However, the code structure allows for changes in the functions without extraordinary effort. The material model formulation, implementation, characterization and use cases are presented.

  9. QUANTUM MECHANICS, GENERAL PHYSICS; 74 ATOMIC AND MOLECULAR PHYSICS...

    Office of Scientific and Technical Information (OSTI)

    of model atoms in fields Milonni, P.W. 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; OPTICAL MODELS; QUANTUM MECHANICS;...

  10. Uncertainty Quantification and Management for Multi-scale Nuclear Materials Modeling

    SciTech Connect (OSTI)

    McDowell, David; Deo, Chaitanya; Zhu, Ting; Wang, Yan

    2015-10-21

    Understanding and improving microstructural mechanical stability in metals and alloys is central to the development of high strength and high ductility materials for cladding and cores structures in advanced fast reactors. Design and enhancement of radiation-induced damage tolerant alloys are facilitated by better understanding the connection of various unit processes to collective responses in a multiscale model chain, including: dislocation nucleation, absorption and desorption at interfaces; vacancy production, radiation-induced segregation of Cr and Ni at defect clusters (point defect sinks) in BCC Fe-Cr ferritic/martensitic steels; investigation of interaction of interstitials and vacancies with impurities (V, Nb, Ta, Mo, W, Al, Si, P, S); time evolution of swelling (cluster growth) phenomena of irradiated materials; and energetics and kinetics of dislocation bypass of defects formed by interstitial clustering and formation of prismatic loops, informing statistical models of continuum character with regard to processes of dislocation glide, vacancy agglomeration and swelling, climb and cross slip.

  11. Subsurface Uranium Fate and Transport: Integrated Experiments and Modeling of Coupled Biogeochemical Mechanisms of Nanocrystalline Uraninite Oxidation by Fe(III)-(hydr)oxides - Project Final Report

    SciTech Connect (OSTI)

    Peyton, Brent M. [Montana State University; Timothy, Ginn R. [University of California Davis; Sani, Rajesh K. [South Dakota School of Mines and Technology

    2013-08-14

    Subsurface bacteria including sulfate reducing bacteria (SRB) reduce soluble U(VI) to insoluble U(IV) with subsequent precipitation of UO2. We have shown that SRB reduce U(VI) to nanometer-sized UO2 particles (1-5 nm) which are both intra- and extracellular, with UO2 inside the cell likely physically shielded from subsequent oxidation processes. We evaluated the UO2 nanoparticles produced by Desulfovibrio desulfuricans G20 under growth and non-growth conditions in the presence of lactate or pyruvate and sulfate, thiosulfate, or fumarate, using ultrafiltration and HR-TEM. Results showed that a significant mass fraction of bioreduced U (35-60%) existed as a mobile phase when the initial concentration of U(VI) was 160 M. Further experiments with different initial U(VI) concentrations (25 - 900 ?M) in MTM with PIPES or bicarbonate buffers indicated that aggregation of uraninite depended on the initial concentrations of U(VI) and type of buffer. It is known that under some conditions SRB-mediated UO2 nanocrystals can be reoxidized (and thus remobilized) by Fe(III)-(hydr)oxides, common constituents of soils and sediments. To elucidate the mechanism of UO2 reoxidation by Fe(III) (hydr)oxides, we studied the impact of Fe and U chelating compounds (citrate, NTA, and EDTA) on reoxidation rates. Experiments were conducted in anaerobic batch systems in PIPES buffer. Results showed EDTA significantly accelerated UO2 reoxidation with an initial rate of 9.5?M day-1 for ferrihydrite. In all cases, bicarbonate increased the rate and extent of UO2 reoxidation with ferrihydrite. The highest rate of UO2 reoxidation occurred when the chelator promoted UO2 and Fe(III) (hydr)oxide dissolution as demonstrated with EDTA. When UO2 dissolution did not occur, UO2 reoxidation likely proceeded through an aqueous Fe(III) intermediate as observed for both NTA and citrate. To complement to these laboratory studies, we collected U-bearing samples from a surface seep at the Rifle field site and have measured elevated U concentrations in oxic iron-rich sediments. To translate experimental results into numerical analysis of U fate and transport, a reaction network was developed based on Sani et al. (2004) to simulate U(VI) bioreduction with concomitant UO2 reoxidation in the presence of hematite or ferrihydrite. The reduction phase considers SRB reduction (using lactate) with the reductive dissolution of Fe(III) solids, which is set to be microbially mediated as well as abiotically driven by sulfide. Model results show the oxidation of HS by Fe(III) directly competes with UO2 reoxidation as Fe(III) oxidizes HS preferentially over UO2. The majority of Fe reduction is predicted to be abiotic, with ferrihydrite becoming fully consumed by reaction with sulfide. Predicted total dissolved carbonate concentrations from the degradation of lactate are elevated (log(pCO2) ~ 1) and, in the hematite system, yield close to two orders-of-magnitude higher U(VI) concentrations than under initial carbonate concentrations of 3 mM. Modeling of U(VI) bioreduction with concomitant reoxidation of UO2 in the presence of ferrihydrite was also extended to a two-dimensional field-scale groundwater flow and biogeochemically reactive transport model for the South Oyster site in eastern Virginia. This model was developed to simulate the field-scale immobilization and subsequent reoxidation of U by a biologically mediated reaction network.

  12. Mathematical and Numerical Analyses of Peridynamics for Multiscale Materials Modeling

    SciTech Connect (OSTI)

    Du, Qiang

    2014-11-12

    The rational design of materials, the development of accurate and efficient material simulation algorithms, and the determination of the response of materials to environments and loads occurring in practice all require an understanding of mechanics at disparate spatial and temporal scales. The project addresses mathematical and numerical analyses for material problems for which relevant scales range from those usually treated by molecular dynamics all the way up to those most often treated by classical elasticity. The prevalent approach towards developing a multiscale material model couples two or more well known models, e.g., molecular dynamics and classical elasticity, each of which is useful at a different scale, creating a multiscale multi-model. However, the challenges behind such a coupling are formidable and largely arise because the atomistic and continuum models employ nonlocal and local models of force, respectively. The project focuses on a multiscale analysis of the peridynamics materials model. Peridynamics can be used as a transition between molecular dynamics and classical elasticity so that the difficulties encountered when directly coupling those two models are mitigated. In addition, in some situations, peridynamics can be used all by itself as a material model that accurately and efficiently captures the behavior of materials over a wide range of spatial and temporal scales. Peridynamics is well suited to these purposes because it employs a nonlocal model of force, analogous to that of molecular dynamics; furthermore, at sufficiently large length scales and assuming smooth deformation, peridynamics can be approximated by classical elasticity. The project will extend the emerging mathematical and numerical analysis of peridynamics. One goal is to develop a peridynamics-enabled multiscale multi-model that potentially provides a new and more extensive mathematical basis for coupling classical elasticity and molecular dynamics, thus enabling next generation atomistic-to-continuum multiscale simulations. In addition, a rigorous studyof nite element discretizations of peridynamics will be considered. Using the fact that peridynamics is spatially derivative free, we will also characterize the space of admissible peridynamic solutions and carry out systematic analyses of the models, in particular rigorously showing how peridynamics encompasses fracture and other failure phenomena. Additional aspects of the project include the mathematical and numerical analysis of peridynamics applied to stochastic peridynamics models. In summary, the project will make feasible mathematically consistent multiscale models for the analysis and design of advanced materials.

  13. Residential Mechanical Precooling

    SciTech Connect (OSTI)

    German, a.; Hoeschele, M.

    2014-12-01

    This research conducted by the Alliance for Residential Building Innovation team evaluated mechanical air conditioner pre-cooling strategies in homes throughout the United States. EnergyPlus modeling evaluated two homes with different performance characteristics in seven climates. Results are applicable to new construction homes and most existing homes built in the last 10 years, as well as fairly efficient retrofitted homes.

  14. Fractofusion mechanism

    SciTech Connect (OSTI)

    Yasui, K. . Dept. of Physics)

    1992-11-01

    In this paper, the fractofusion mechanism of cold fusion is investigated theoretically. The conditions necessary for fractofusion during the absorption of deuterium atoms by palladium specimens (the condition of so-called cold fusion experiments) is clarified, including crack generation at grain boundaries, the high orientation angle of grains, rapid crack formation, the increase of electrical resistance around a crack, the large width of cracks, and the generation of many cracks. The origin and quantity of the electrical field inside cracks in the conductor are also clarified. By the fractofusion mechanism, the experimental facts that neutron emissions are observed in bursts, that sometimes they coincide with the deformation of a palladium specimen, and that in many experiments excess neutrons were not observed are qualitatively explained. The upper limit of the total fractofusion yields during the absorption of deuterium atoms by palladium specimens are estimated.

  15. Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    PVLibMatlab Permalink Gallery Sandia Labs Releases New Version of PVLib Toolbox Modeling, News, Photovoltaic, Solar Sandia Labs Releases New Version of PVLib Toolbox Sandia has released version 1.3 of PVLib, its widely used Matlab toolbox for modeling photovoltaic (PV) power systems. The version 1.3 release includes the following added functions: functions to estimate parameters for popular PV module models, including PVsyst and the CEC '5 parameter' model a new model of the effects of solar

  16. DAMAGE MODELING OF INJECTION-MOLDED SHORT- AND LONG-FIBER THERMOPLASTICS

    SciTech Connect (OSTI)

    Nguyen, Ba Nghiep; Kunc, Vlastimil; Bapanapalli, Satish K.; Phelps, Jay; Tucker III, Charles L.

    2009-10-30

    This article applies the recent anisotropic rotary diffusion reduced strain closure (ARD-RSC) model for predicting fiber orientation and a new damage model for injection-molded long-fiber thermoplastics (LFTs) to analyze progressive damage leading to total failure of injection-molded long-glass-fiber/polypropylene (PP) specimens. The ARD-RSC model was implemented in a research version of the Autodesk Moldflow Plastics Insight (MPI) processing code, and it has been used to simulate injection-molding of a long-glass-fiber/PP plaque. The damage model combines micromechanical modeling with a continuum damage mechanics description to predict the nonlinear behavior due to plasticity coupled with damage in LFTs. This model has been implemented in the ABAQUS finite element code via user-subroutines and has been used in the damage analyses of tensile specimens removed from the injection-molded long-glass-fiber/PP plaques. Experimental characterization and mechanical testing were performed to provide input data to support and validate both process modeling and damage analyses. The predictions are in agreement with the experimental results.

  17. Eulerian hydrocode modeling of a dynamic tensile extrusion experiment (u)

    SciTech Connect (OSTI)

    Burkett, Michael W; Clancy, Sean P

    2009-01-01

    Eulerian hydrocode simulations utilizing the Mechanical Threshold Stress flow stress model were performed to provide insight into a dynamic extrusion experiment. The dynamic extrusion response of copper (three different grain sizes) and tantalum spheres were simulated with MESA, an explicit, 2-D Eulerian continuum mechanics hydrocode and compared with experimental data. The experimental data consisted of high-speed images of the extrusion process, recovered extruded samples, and post test metallography. The hydrocode was developed to predict large-strain and high-strain-rate loading problems. Some of the features of the features of MESA include a high-order advection algorithm, a material interface tracking scheme and a van Leer monotonic advection-limiting. The Mechanical Threshold Stress (MTS) model was utilized to evolve the flow stress as a function of strain, strain rate and temperature for copper and tantalum. Plastic strains exceeding 300% were predicted in the extrusion of copper at 400 m/s, while plastic strains exceeding 800% were predicted for Ta. Quantitative comparisons between the predicted and measured deformation topologies and extrusion rate were made. Additionally, predictions of the texture evolution (based upon the deformation rate history and the rigid body rotations experienced by the copper during the extrusion process) were compared with the orientation imaging microscopy measurements. Finally, comparisons between the calculated and measured influence of the initial texture on the dynamic extrusion response of tantalum was performed.

  18. Vehicle Technologies Office Merit Review 2014: Coupling of Mechanical Behavior of Cell Components to Electrochemical-Thermal Models for Computer-Aided Engineering of Batteries under Abuse

    Broader source: Energy.gov [DOE]

    Presentation given by NREL at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about coupling of mechanical behavior of cell...

  19. Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Engine Combustion/Modeling - Modelingadmin2015-10-28T01:54:52+00:00 Modelers at the CRF are developing high-fidelity simulation tools for engine combustion and detailed micro-kinetic, surface chemistry modeling tools for catalyst-based exhaust aftertreatment systems. The engine combustion modeling is focused on developing Large Eddy Simulation (LES). LES is being used with closely coupled key target experiments to reveal new understanding of the fundamental processes involved in engine

  20. Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Reacting Flow/Modeling - Modelingadmin2015-10-28T02:39:13+00:00 Turbulence models typically involve coarse-graining and/or time averaging. Though adequate for modeling mean transport, this approach does not address turbulence-microphysics interactions that are important in combustion processes. Subgrid models are developed to represent these interactions. The CRF has developed a fundamentally different representation of these interactions that does not involve distinct coarse-grained and subgrid

  1. Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Widespread Hydrogen Fueling Infrastructure Is the Goal of H2FIRST Project Capabilities, Center for Infrastructure Research and Innovation (CIRI), Computational Modeling & Simulation, Energy, Energy Storage, Energy Storage Systems, Facilities, Infrastructure Security, Materials Science, Modeling, Modeling & Analysis, News, News & Events, Partnership, Research & Capabilities, Systems Analysis, Systems Engineering, Transportation Energy Widespread Hydrogen Fueling Infrastructure Is

  2. Modeling and Algorithmic Approaches to Constitutively-Complex, Microstructured Fluids

    SciTech Connect (OSTI)

    Miller, Gregory H.; Forest, Gregory

    2011-12-22

    We present a new multiscale model for complex uids based on three scales: microscopic, kinetic, and continuum. We choose the microscopic level as Kramers' bead-rod model for polymers, which we describe as a system of stochastic di#11;erential equations with an implicit constraint formulation. The associated Fokker-Planck equation is then derived, and adiabatic elimination removes the fast momentum coordinates. Approached in this way, the kinetic level reduces to a dispersive drift equation. The continuum level is modeled with a #12;nite volume Godunov-projection algorithm. We demonstrate computation of viscoelastic stress divergence using this multiscale approach.

  3. Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    WVMinputs-outputs Permalink Gallery Sandia Labs releases wavelet variability model (WVM) Modeling, News, Photovoltaic, Solar Sandia Labs releases wavelet variability model (WVM) When a single solar photovoltaic (PV) module is in full sunlight, then is shaded by a cloud, and is back in full sunlight in a matter of seconds, a sharp dip then increase in power output will result. However, over an entire PV plant, clouds will often uncover some modules even as they cover others, [...] By Andrea

  4. Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    New Project Is the ACME of Computer Science to Address Climate Change Analysis, Climate, Global Climate & Energy, Modeling, Modeling & Analysis, News, News & Events, Partnership New Project Is the ACME of Computer Science to Address Climate Change Sandia high-performance computing (HPC) researchers are working with DOE and 14 other national laboratories and institutions to develop and apply the most complete climate and Earth system model, to address the most challenging and

  5. Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A rail tank car of the type used to transport crude oil across North America. Recent incidents have raised concerns about the safety of this practice, which the DOE-DOT-sponsored team is investigating. (photo credit: Harvey Henkelmann) Permalink Gallery Expansion of DOE-DOT Tight Oil Research Work Capabilities, Carbon Capture & Storage, Carbon Storage, Energy, Energy Assurance, Energy Assurance, Fuel Options, Infrastructure Assurance, Infrastructure Security, Modeling, Modeling, Modeling

  6. Methods for modeling impact-induced reactivity changes in small reactors.

    SciTech Connect (OSTI)

    Tallman, Tyler N.; Radel, Tracy E.; Smith, Jeffrey A.; Villa, Daniel L.; Smith, Brandon M.; Radel, Ross F.; Lipinski, Ronald J.; Wilson, Paul Philip Hood

    2010-10-01

    This paper describes techniques for determining impact deformation and the subsequent reactivity change for a space reactor impacting the ground following a potential launch accident or for large fuel bundles in a shipping container following an accident. This technique could be used to determine the margin of subcriticality for such potential accidents. Specifically, the approach couples a finite element continuum mechanics model (Pronto3D or Presto) with a neutronics code (MCNP). DAGMC, developed at the University of Wisconsin-Madison, is used to enable MCNP geometric queries to be performed using Pronto3D output. This paper summarizes what has been done historically for reactor launch analysis, describes the impact criticality analysis methodology, and presents preliminary results using representative reactor designs.

  7. Scaling and the continuum limit of the finite temperature deconfinement transition in SU(N{sub c}) pure gauge theory

    SciTech Connect (OSTI)

    Datta, Saumen; Gupta, Sourendu

    2009-12-01

    We investigated the finite temperature (T) phase transition for SU(N{sub c}) gauge theory with N{sub c}=4, 6, 8 and 10 at lattice spacing, a, of 1/(6T) or less. We checked that these theories have first-order transitions at such small a. In many cases we were able to find the critical couplings with precision as good as a few parts in 10{sup 4}. We also investigated the use of two-loop renormalization group equations in extrapolating the lattice results to the continuum, thus fixing the temperature scale in units of the phase transition temperature, T{sub c}. We found that when a{<=}1/(8T{sub c}) the two-loop extrapolation was accurate to about 1%-2%. However, we found that trading T{sub c} for the QCD scale, {lambda}{sub MS}, increases uncertainties significantly, to the level of about 5%-10%.

  8. Determining mechanical behavior of solid materials using miniature specimens

    DOE Patents [OSTI]

    Manahan, Michael P. (Columbus, OH); Argon, Ali S. (Belmont, MA); Harling, Otto K. (Hingham, MA)

    1986-01-01

    A Miniaturized Bend Test (MBT) capable of extracting and determining mechanical behavior information from specimens only so large as to have at least a volume or smallest dimension sufficient to satisfy continuum behavior in all directions. The mechanical behavior of the material is determined from the measurements taken during the bending of the specimen and is processed according to the principles of linear or nonlinear material mechanics or both. In a preferred embodiment the determination is carried out by a code which is constructed according to the finite element method, and the specimen used for the determinations is a miniature disk simply supported for central loading at the axis on the center of the disk.

  9. Determining mechanical behavior of solid materials using miniature specimens

    DOE Patents [OSTI]

    Manahan, M.P.; Argon, A.S.; Harling, O.K.

    1986-02-04

    A Miniaturized Bend Test (MBT) capable of extracting and determining mechanical behavior information from specimens only so large as to have at least a volume or smallest dimension sufficient to satisfy continuum behavior in all directions is disclosed. The mechanical behavior of the material is determined from the measurements taken during the bending of the specimen and is processed according to the principles of linear or nonlinear material mechanics or both. In a preferred embodiment the determination is carried out by a code which is constructed according to the finite element method, and the specimen used for the determinations is a miniature disk simply supported for central loading at the axis on the center of the disk. 51 figs.

  10. HST-COS OBSERVATIONS OF AGNs. I. ULTRAVIOLET COMPOSITE SPECTRA OF THE IONIZING CONTINUUM AND EMISSION LINES

    SciTech Connect (OSTI)

    Shull, J. Michael; Stevans, Matthew; Danforth, Charles W., E-mail: michael.shull@colorado.edu, E-mail: matthew.stevans@colorado.edu, E-mail: charles.danforth@colorado.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States)

    2012-06-20

    The ionizing fluxes from quasars and other active galactic nuclei (AGNs) are critical for interpreting the emission-line spectra of AGNs and for photoionization and heating of the intergalactic medium. Using ultraviolet spectra from the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST), we have directly measured the rest-frame ionizing continua and emission lines for 22 AGNs. Over the redshift range 0.026 < z < 1.44, COS samples the Lyman continuum and many far-UV emission lines (Ly{alpha} {lambda}1216, C IV {lambda}1549, Si IV/O IV] {lambda}1400, N V {lambda}1240, O VI {lambda}1035). Strong EUV emission lines with 14-22 eV excitation energies (Ne VIII {lambda}{lambda}770, 780, Ne V {lambda}569, O II {lambda}834, O III {lambda}833, {lambda}702, O IV {lambda}788, 608, 554, O V {lambda}630, N III {lambda}685) suggest the presence of hot gas in the broad emission-line region. The rest-frame continuum, F{sub {nu}}{proportional_to}{nu}{sup {alpha}{sub {nu}}}, shows a break at wavelengths {lambda} < 1000 A, with spectral index {alpha}{sub {nu}} = -0.68 {+-} 0.14 in the FUV (1200-2000 A) steepening to {alpha}{sub {nu}} = -1.41 {+-} 0.21 in the EUV (500-1000 A). The COS EUV index is similar to that of radio-quiet AGNs in the 2002 HST/FOS survey ({alpha}{sub {nu}} = -1.57 {+-} 0.17). We see no Lyman edge ({tau}{sub HI} < 0.03) or He I {lambda}584 emission in the AGN composite. Our 22 AGNs exhibit a substantial range of FUV/EUV spectral indices and a correlation with AGN luminosity and redshift, likely due to observing below the 1000 A spectral break.

  11. Mechanisms of hydrogen-assisted fracture in austenitic stainless steel welds.

    SciTech Connect (OSTI)

    Balch, Dorian K.; Sofronis, Petros; Somerday, Brian P.; Novak, Paul

    2005-03-01

    The objective of this study was to quantify the hydrogen-assisted fracture susceptibility of gas-tungsten arc (GTA) welds in the nitrogen-strengthened, austenitic stainless steels 21Cr-6Ni-9Mn (21-6-9) and 22Cr-13Ni-5Mn (22-13-5). In addition, mechanisms of hydrogen-assisted fracture in the welds were identified using electron microscopy and finite-element modeling. Elastic-plastic fracture mechanics experiments were conducted on hydrogen-charged GTA welds at 25 C. Results showed that hydrogen dramatically lowered the fracture toughness from 412 kJ/m{sup 2} to 57 kJ/m{sup 2} in 21-6-9 welds and from 91 kJ/m{sup 2} to 26 kJ/m{sup 2} in 22-13-5 welds. Microscopy results suggested that hydrogen served two roles in the fracture of welds: it promoted the nucleation of microcracks along the dendritic structure and accelerated the link-up of microcracks by facilitating localized deformation. A continuum finite-element model was formulated to test the notion that hydrogen could facilitate localized deformation in the ligament between microcracks. On the assumption that hydrogen decreased local flow stress in accordance with the hydrogen-enhanced dislocation mobility argument, the finite-element results showed that deformation was localized in a narrow band between two parallel, overlapping microcracks. In contrast, in the absence of hydrogen, the finite-element results showed that deformation between microcracks was more uniformly distributed.

  12. Modeling Coupled THMC Processes and Brine Migration in Salt at High Temperatures

    SciTech Connect (OSTI)

    Rutqvist, Jonny; Blanco Martin, Laura; Mukhopadhyay, Sumit; Houseworth, Jim; Birkholzer, Jens

    2014-08-14

    In this report, we present FY2014 progress by Lawrence Berkeley National Laboratory (LBNL) related to modeling of coupled thermal-hydrological-mechanical-chemical (THMC) processes in salt and their effect on brine migration at high temperatures. LBNLs work on the modeling of coupled THMC processes in salt was initiated in FY2012, focusing on exploring and demonstrating the capabilities of an existing LBNL modeling tool (TOUGH-FLAC) for simulating temperature-driven coupled flow and geomechanical processes in salt. This work includes development related to, and implementation of, essential capabilities, as well as testing the model against relevant information and published experimental data related to the fate and transport of water. we provide more details on the FY2014 work, first presenting updated tools and improvements made to the TOUGH-FLAC simulator, and the use of this updated tool in a new model simulation of long-term THM behavior within a generic repository in a salt formation. This is followed by the description of current benchmarking and validations efforts, including the TSDE experiment. We then present the current status in the development of constitutive relationships and the dual-continuum model for brine migration. We conclude with an outlook for FY2015, which will be much focused on model validation against field experiments and on the use of the model for the design studies related to a proposed heater experiment.

  13. Two-particle correlations in continuum dipole transitions in Borromean nuclei

    SciTech Connect (OSTI)

    Hagino, K.; Sagawa, H.; Nakamura, T.; Shimoura, S.

    2009-09-15

    We study the energy and angular distributions of two emitted neutrons from the dipole excitation of two typical, weakly bound Borromean nuclei, {sup 11}Li and {sup 6}He, by using a three-body model. Our calculation indicates that those distributions are considerably different between the two nuclei, even though both the nuclei exhibit similar strong dineutron correlations in the ground state to each other. We point out that this different behavior primarily reflects the interaction between the neutron and the core nucleus, especially the s-wave virtual state in {sup 10}Li, rather than the interaction between the valence neutrons.

  14. Studies of light neutron-excess systems from bounds to continuum

    SciTech Connect (OSTI)

    Ito, Makoto; Otsu, Hideaki

    2012-10-20

    The generalized two-center cluster model (GTCM), which can handle various single particle configurations in general two center systems, is applied to the light neutron-rich system, {sup 12}Be = {alpha}+{alpha}+4N. We discuss the change of the neutrons' configuration around two {alpha}-cores as a variation of an excitation energy. We show that the excess neutrons form various chemical-bondinglike configurations around two {alpha} cores in the unbound region above the {alpha} decay threshold. The possibility of the {alpha} cluster formation in the heavier neutron-excess system, {sup 28}Ne, is also discussed.

  15. Foam process models.

    SciTech Connect (OSTI)

    Moffat, Harry K.; Noble, David R.; Baer, Thomas A.; Adolf, Douglas Brian; Rao, Rekha Ranjana; Mondy, Lisa Ann

    2008-09-01

    In this report, we summarize our work on developing a production level foam processing computational model suitable for predicting the self-expansion of foam in complex geometries. The model is based on a finite element representation of the equations of motion, with the movement of the free surface represented using the level set method, and has been implemented in SIERRA/ARIA. An empirically based time- and temperature-dependent density model is used to encapsulate the complex physics of foam nucleation and growth in a numerically tractable model. The change in density with time is at the heart of the foam self-expansion as it creates the motion of the foam. This continuum-level model uses an homogenized description of foam, which does not include the gas explicitly. Results from the model are compared to temperature-instrumented flow visualization experiments giving the location of the foam front as a function of time for our EFAR model system.

  16. Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in warm dense matter experiments with diffuse interface methods in the ALE-AMR code Wangyi Liu ∗ , John Barnard, Alex Friedman, Nathan Masters, Aaron Fisher, Velemir Mlaker, Alice Koniges, David Eder † August 4, 2011 Abstract In this paper we describe an implementation of a single-fluid inter- face model in the ALE-AMR code to simulate surface tension effects. The model does not require explicit information on the physical state of the two phases. The only change to the existing fluid

  17. Evaluation of New and Proposed Organic Aerosol Sources and Mechanisms using the Aerosol Modeling Testbed. MILAGRO, CARES, CalNex, BEACHON, and GVAX

    SciTech Connect (OSTI)

    Hodzic, Alma; Jimenez, Jose L.

    2015-04-09

    This work investigated the formation and evolution of organic aerosols (OA) arising from anthropogenic and biogenic sources in a framework that combined state-of-the-science process and regional modeling, and their evaluation against advanced and emerging field measurements. Although OA are the dominant constituents of submicron particles, our understanding of their atmospheric lifecycle is limited, and current models fail to describe the observed amounts and properties of chemically formed secondary organic aerosols (SOA), leaving large uncertainties on the effects of SOA on climate. Our work has provided novel modeling constraints on sources, formation, aging and removal of SOA by investigating in particular (i) the contribution of trash burning emissions to OA levels in a megacity, (ii) the contribution of glyoxal to SOA formation in aqueous particles in California during CARES/CalNex and over the continental U.S., (iii) SOA formation and regional growth over a pine forest in Colorado and its sensitivity to anthropogenic NOx levels during BEACHON, and the sensitivity of SOA to (iv) the sunlight exposure during its atmospheric lifetime, and to (v) changes in solubility and removal of organic vapors in the urban plume (MILAGRO, Mexico City), and over the continental U.S.. We have also developed a parameterization of water solubility for condensable organic gases produced from major anthropogenic and biogenic precursors based on explicit chemical modeling, and made it available to the wider community. This work used for the first time constraints from the explicit model GECKO-A to improve SOA representation in 3D regional models such as WRF-Chem.

  18. Multiscale modeling for fluid transport in nanosystems.

    SciTech Connect (OSTI)

    Lee, Jonathan W.; Jones, Reese E.; Mandadapu, Kranthi Kiran; Templeton, Jeremy Alan; Zimmerman, Jonathan A.

    2013-09-01

    Atomistic-scale behavior drives performance in many micro- and nano-fluidic systems, such as mircrofludic mixers and electrical energy storage devices. Bringing this information into the traditionally continuum models used for engineering analysis has proved challenging. This work describes one such approach to address this issue by developing atomistic-to-continuum multi scale and multi physics methods to enable molecular dynamics (MD) representations of atoms to incorporated into continuum simulations. Coupling is achieved by imposing constraints based on fluxes of conserved quantities between the two regions described by one of these models. The impact of electric fields and surface charges are also critical, hence, methodologies to extend finite-element (FE) MD electric field solvers have been derived to account for these effects. Finally, the continuum description can have inconsistencies with the coarse-grained MD dynamics, so FE equations based on MD statistics were derived to facilitate the multi scale coupling. Examples are shown relevant to nanofluidic systems, such as pore flow, Couette flow, and electric double layer.

  19. Viscoelastic Model for Lung Parenchyma for Multi-Scale Modeling of Respiratory System, Phase II: Dodecahedral Micro-Model

    SciTech Connect (OSTI)

    Freed, Alan D.; Einstein, Daniel R.; Carson, James P.; Jacob, Rick E.

    2012-03-01

    In the first year of this contractual effort a hypo-elastic constitutive model was developed and shown to have great potential in modeling the elastic response of parenchyma. This model resides at the macroscopic level of the continuum. In this, the second year of our support, an isotropic dodecahedron is employed as an alveolar model. This is a microscopic model for parenchyma. A hopeful outcome is that the linkage between these two scales of modeling will be a source of insight and inspiration that will aid us in the final year's activity: creating a viscoelastic model for parenchyma.

  20. THE FAR-ULTRAVIOLET 'CONTINUUM' IN PROTOPLANETARY DISK SYSTEMS. II. CARBON MONOXIDE FOURTH POSITIVE EMISSION AND ABSORPTION

    SciTech Connect (OSTI)

    France, Kevin; Schindhelm, Eric; Burgh, Eric B.; Brown, Alexander; Green, James C.; Herczeg, Gregory J.; Brown, Joanna M.; Harper, Graham M.; Linsky, Jeffrey L.; Yang Hao; Abgrall, Herve; Ardila, David R.; Bergin, Edwin; Bethell, Thomas; Calvet, Nuria; Ingleby, Laura; Espaillat, Catherine; Gregory, Scott G.; Hillenbrand, Lynne A.; Hussain, Gaitee

    2011-06-10

    We exploit the high sensitivity and moderate spectral resolution of the Hubble Space Telescope Cosmic Origins Spectrograph to detect far-ultraviolet (UV) spectral features of carbon monoxide (CO) present in the inner regions of protoplanetary disks for the first time. We present spectra of the classical T Tauri stars HN Tau, RECX-11, and V4046 Sgr, representative of a range of CO radiative processes. HN Tau shows CO bands in absorption against the accretion continuum. The CO absorption most likely arises in warm inner disk gas. We measure a CO column density and rotational excitation temperature of N(CO) = (2 {+-} 1) x 10{sup 17} cm{sup -2} and T{sub rot}(CO) 500 {+-} 200 K for the absorbing gas. We also detect CO A-X band emission in RECX-11 and V4046 Sgr, excited by UV line photons, predominantly H I Ly{alpha}. All three objects show emission from CO bands at {lambda} > 1560 A, which may be excited by a combination of UV photons and collisions with non-thermal electrons. In previous observations these emission processes were not accounted for due to blending with emission from the accretion shock, collisionally excited H{sub 2}, and photo-excited H{sub 2}, all of which appeared as a 'continuum' whose components could not be separated. The CO emission spectrum is strongly dependent upon the shape of the incident stellar Ly{alpha} emission profile. We find CO parameters in the range: N(CO) {approx} 10{sup 18}-10{sup 19} cm{sup -2}, T{sub rot}(CO) {approx}> 300 K for the Ly{alpha}-pumped emission. We combine these results with recent work on photo-excited and collisionally excited H{sub 2} emission, concluding that the observations of UV-emitting CO and H{sub 2} are consistent with a common spatial origin. We suggest that the CO/H{sub 2} ratio ({identical_to} N(CO)/N(H{sub 2})) in the inner disk is {approx}1, a transition between the much lower interstellar value and the higher value observed in solar system comets today, a result that will require future observational and theoretical study to confirm.

  1. modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    modeling - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs Advanced Nuclear Energy

  2. Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    NASA Earth at Night Video EC, Energy, Energy Efficiency, Global, Modeling, News & Events, Solid-State Lighting, Videos NASA Earth at Night Video Have you ever wondered what the Earth looks like at night? NASA provides a clear, cloud-free view of the Earth at night using the Suomi National Polar-orbiting Partnership Satellite. The satellite utilizes an instrument known as the Visible Infrared Radiometer Suite (VIIRS), which allows the satellite to capture images of a "remarkably detailed

  3. Development of Advanced Thermal-Hydrological-Mechanical-Chemical (THMC)

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Modeling Capabilities for Enhanced Geothermal Systems | Department of Energy Development of Advanced Thermal-Hydrological-Mechanical-Chemical (THMC) Modeling Capabilities for Enhanced Geothermal Systems Development of Advanced Thermal-Hydrological-Mechanical-Chemical (THMC) Modeling Capabilities for Enhanced Geothermal Systems Development of Advanced Thermal-Hydrological-Mechanical-Chemical (THMC) Modeling Capabilities for Enhanced Geothermal Systems presentation at the April 2013 peer

  4. Modeling

    SciTech Connect (OSTI)

    Loth, E.; Tryggvason, G.; Tsuji, Y.; Elghobashi, S. E.; Crowe, Clayton T.; Berlemont, A.; Reeks, M.; Simonin, O.; Frank, Th; Onishi, Yasuo; Van Wachem, B.

    2005-09-01

    Slurry flows occur in many circumstances, including chemical manufacturing processes, pipeline transfer of coal, sand, and minerals; mud flows; and disposal of dredged materials. In this section we discuss slurry flow applications related to radioactive waste management. The Hanford tank waste solids and interstitial liquids will be mixed to form a slurry so it can be pumped out for retrieval and treatment. The waste is very complex chemically and physically. The ARIEL code is used to model the chemical interactions and fluid dynamics of the waste.

  5. Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    diffuse interface methods in ALE-AMR code with application in modeling NDCX-II experiments Wangyi Liu 1 , John Barnard 2 , Alex Friedman 2 , Nathan Masters 2 , Aaron Fisher 2 , Alice Koniges 2 , David Eder 2 1 LBNL, USA, 2 LLNL, USA This work was part of the Petascale Initiative in Computational Science at NERSC, supported by the Director, Office of Science, Advanced Scientific Computing Research, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. This work was performed

  6. THE SPECTRAL EVOLUTION OF THE FIRST GALAXIES. II. SPECTRAL SIGNATURES OF LYMAN CONTINUUM LEAKAGE FROM GALAXIES IN THE REIONIZATION EPOCH

    SciTech Connect (OSTI)

    Zackrisson, Erik; Jensen, Hannes; Inoue, Akio K.

    2013-11-01

    The fraction of ionizing photons that escape (f{sub esc}) from z ?> 6 galaxies is an important parameter for assessing the role of these objects in the reionization of the universe, but the opacity of the intergalactic medium precludes a direct measurement of f{sub esc} for individual galaxies at these epochs. We argue that since f{sub esc} regulates the impact of nebular emission on the spectra of galaxies, it should nonetheless be possible to indirectly probe f{sub esc} well into the reionization epoch. As a first step, we demonstrate that by combining measurements of the rest-frame UV slope ? with the equivalent width of the H? emission line, galaxies with very high Lyman continuum escape fractions (f{sub esc} ? 0.5) should be identifiable up to z ? 9 through spectroscopy with the upcoming James Webb Space Telescope (JWST). By targeting strongly lensed galaxies behind low-redshift galaxy clusters, JWST spectra of sufficiently good quality can be obtained for M{sub 1500} ?< 16.0 galaxies at z ? 7 and for M{sub 1500} ?< 17.5 galaxies at z ? 9. Dust-obscured star formation may complicate the analysis, but supporting observations with ALMA or the planned SPICA mission may provide useful constraints on this effect.

  7. THE GREAT OBSERVATORIES ORIGINS DEEP SURVEY: CONSTRAINTS ON THE LYMAN CONTINUUM ESCAPE FRACTION DISTRIBUTION OF LYMAN-BREAK GALAXIES AT 3.4 < z < 4.5

    SciTech Connect (OSTI)

    Vanzella, E.; Nonino, M.; Fontanot, F.; Cristiani, S.; Tozzi, P.; Giavalisco, M.; Inoue, A. K.; Grazian, A.; Giallongo, E.; Boutsia, K.; Fontana, A.; Pentericci, L.; Dickinson, M.; Stern, D.; Ferguson, H.; Spinrad, H.; Rosati, P.

    2010-12-10

    We use ultra-deep ultraviolet VLT/VIMOS intermediate-band and VLT/FORS1 narrowband imaging in the GOODS Southern field to derive limits on the distribution of the escape fraction (f{sub esc}) of ionizing radiation for L {>=} L*{sub z=3} Lyman-break galaxies (LBGs) at redshift 3.4-4.5. Only one LBG, at redshift z = 3.795, is detected in its Lyman continuum (LyC; S/N {approx_equal} 5.5), the highest redshift galaxy currently known with a direct detection. Its ultraviolet morphology is quite compact (R{sub eff} = 0.8 kpc physical). Three out of seven active galactic nuclei are also detected in their LyC, including one at redshift z = 3.951 and z{sub 850} = 26.1. From stacked data (LBGs), we set an upper limit to the average f{sub esc} in the range 5%-20%, depending on how the data are selected (e.g., by magnitude and/or redshift). We undertake extensive Monte Carlo simulations that take into account intergalactic attenuation, stellar population synthesis models, dust extinction, and photometric noise in order to explore the moments of the distribution of the escaping radiation. Various distributions (exponential, log-normal, and Gaussian) are explored. We find that the median f{sub esc} is lower than {approx_equal}6% with an 84% percentile limit not larger than 20%. If this result remains valid for fainter LBGs down to current observational limits, then the LBG population might be not sufficient to account for the entire photoionization budget at the redshifts considered here, with the exact details dependent upon the assumed ionizing background and QSO contribution thereto. It is possible that f{sub esc} depends on the UV luminosity of the galaxies, with fainter galaxies having higher f{sub esc}, and estimates of f{sub esc} from a sample of faint LBGs from HUDF (i{sub 775} {<=}28.5) are in broad quantitative agreement with such a scenario.

  8. NEAR-INFRARED H{sub 2} AND CONTINUUM SURVEY OF EXTENDED GREEN OBJECTS. II. COMPLETE CENSUS FOR THE NORTHERN GALACTIC PLANE

    SciTech Connect (OSTI)

    Lee, Hsu-Tai; Karr, Jennifer; Su, Yu-Nung; Liu, Sheng-Yuan; Takami, Michihiro; Liao, Wei-Ting; Froebrich, Dirk; Ioannidis, Georgios; Lee, Yong-Hyun; Duan, Hao-Yuan

    2013-10-01

    We discuss 94 Extended Green Objects (EGOs) in the northern Galactic plane cataloged by Cyganowski et al., based on near-infrared narrow H{sub 2} (2.122 ?m) and continuum observations from the United Kingdom Infrared Telescope. This data set is three times larger than the one in our previous study and is unbiased by preselection. As discussed in the previous paper, the morphologies of the 4.5 ?m emission generally resemble those of the near-infrared continuum, but are different from those of the H{sub 2} emission. Of our sample, only 28% of EGOs with H{sub 2} emission show similar morphologies between 4.5 ?m and H{sub 2} emission. These results suggest that the 4.5 ?m emission mainly comes from scattered continuum from the embedded young stellar objects, and partially from H{sub 2} emission. About half of EGOs are associated with H{sub 2} outflows, if the H{sub 2} outflow incompleteness is considered. The H{sub 2} outflow detection rate for EGOs with K-band detections (61%) is significantly higher than for those without K-band detections (36%). This difference may be due to the fact that both H{sub 2} and K-band emissions are associated with outflows, i.e., H{sub 2} emission and K-band continuum are associated with shocks and outflow cavities, respectively. We also compared the correlation between the H{sub 2} outflows and Class I 44 GHz methanol masers from the literature. The methanol masers can be located upstream or downstream of the H{sub 2} outflows and some bright H{sub 2} spots or outflows are not associated with methanol masers, suggesting that methanol masers and H{sub 2} emission trace different excitation conditions.

  9. Large deformation analysis of laminated composite structures by a continuum-based shell element with transverse deformation

    SciTech Connect (OSTI)

    Wung, Pey Min.

    1989-01-01

    In this work, a finite element formulation and associated computer program is developed for the transient large deformation analysis of laminated composite plate/shell structures. In order to satisfy the plate/shell surface traction boundary conditions and to have accurate stress description while maintaining the low cost of the analysis, a newly assumed displacement field theory is formulated by adding higher-order terms to the transverse displacement component of the first-order shear deformation theory. The laminated shell theory is formulated using the Updated Lagrangian description of a general continuum-based theory with assumptions on thickness deformation. The transverse deflection is approximated through the thickness by a quartic polynomial of the thickness coordinate. As a result both the plate/shell surface tractions (including nonzero tangential tractions and nonzero normal pressure) and the interlaminar shear stress continuity conditions at interfaces are satisfied simultaneously. Furthermore, the rotational degree of freedoms become layer dependent quantities and the laminate possesses a transverse deformation capability (i.e the normal strain is no longer zero). Analytical integration through the thickness direction is performed for both the linear analysis and the nonlinear analysis. Resultants of the stress integrations are expressed in terms of the laminate stacking sequence. Consequently, the laminate characteristics in the normal direction can be evaluated precisely and the cost of the overall analysis is reduced. The standard Newmark method and the modified Newton Raphson method are used for the solution of the nonlinear dynamic equilibrium equations. Finally, a variety of numerical examples are presented to demonstrate the validity and efficiency of the finite element program developed herein.

  10. An investigation of a model of the flow pattern transition mechanism in relation to the identification of annular flow of R134a in a vertical tube using various void fraction models and flow regime maps

    SciTech Connect (OSTI)

    Dalkilic, A.S. [Heat and Thermodynamics Division, Department of Mechanical Engineering, Yildiz Technical University, Yildiz, Besiktas, Istanbul 34349 (Turkey); Wongwises, S. [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

    2010-09-15

    In the present study, new experimental data are presented for literature on the prediction of film thickness and identification of flow regime during the co-current downward condensation in a vertical smooth copper tube having an inner diameter of 8.1 mm and a length of 500 mm. R134a and water are used as working fluids in the tube side and annular side of a double tube heat exchanger, respectively. Condensation experiments are done at mass fluxes of 300 and 515 kg m{sup -2} s{sup -1}. The condensing temperatures are between 40 and 50 C; heat fluxes are between 12.65 and 66.61 kW m{sup -2}. The average experimental heat transfer coefficient of the refrigerant HFC-134a is calculated by applying an energy balance based on the energy transferred from the test section. A mathematical model by Barnea et al. based on the momentum balance of liquid and vapor phases is used to determine the condensation film thickness of R134a. The comparative film thickness values are determined indirectly using relevant measured data together with various void fraction models and correlations reported in the open literature. The effects of heat flux, mass flux, and condensation temperature on the film thickness and condensation heat transfer coefficient are also discussed for the laminar and turbulent flow conditions. There is a good agreement between the film thickness results obtained from the theoretical model and those obtained from six of 35 void fraction models in the high mass flux region of R134a. In spite of their different valid conditions, six well-known flow regime maps from the literature are found to be predictive for the annular flow conditions in the test tube in spite of their different operating conditions. (author)

  11. A new coal-permeability model: Internal swelling stress and fracture-matrix interaction

    SciTech Connect (OSTI)

    Liu, H.H.; Rutqvist, J.

    2009-10-01

    We have developed a new coal-permeability model for uniaxial strain and constant confining stress conditions. The model is unique in that it explicitly considers fracture-matrix interaction during coal deformation processes and is based on a newly proposed internal-swelling stress concept. This concept is used to account for the impact of matrix swelling (or shrinkage) on fracture-aperture changes resulting from partial separation of matrix blocks by fractures that do not completely cut through the whole matrix. The proposed permeability model is evaluated with data from three Valencia Canyon coalbed wells in the San Juan Basin, where increased permeability has been observed during CH{sub 4} gas production, as well as with published data from laboratory tests. Model results are generally in good agreement with observed permeability changes. The importance of fracture-matrix interaction in determining coal permeability, demonstrated in this work using relatively simple stress conditions, underscores the need for a dual-continuum (fracture and matrix) mechanical approach to rigorously capture coal-deformation processes under complex stress conditions, as well as the coupled flow and transport processes in coal seams.

  12. Implementation of a thermomechanical model for the simulation of selective laser melting

    SciTech Connect (OSTI)

    Hodge, N. E.; Ferencz, R. M.; Solberg, J. M.

    2014-07-01

    Selective laser melting (SLM) is an additive manufacturing process in which multiple, successive layers of metal powders are heated via laser in order to build a part. Modeling of SLM requires consideration of both heat transfer and solid mechanics. The present work describes continuum modeling of SLM as envisioned for eventual support of part-scale modeling of this fabrication process to determine end-state information such as residual stresses and distortion. The determination of the evolving temperatures is dependent on the material, the state of the material (powder or solid), the specified heating, and the configuration. Similarly, the current configuration is dependent on the temperatures, the powder-solid state, and the constitutive models. A multi-physics numerical formulation is required to solve such problems. This article describes the problem formulation, numerical method, and constitutive parameters necessary to solve such a problem. Additionally, various verification and example problems are simulated in the parallel, multi-physics finite element code Diablo, and the results presented herein.

  13. Mechanics | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Mechanics Mechanics A deeper look at the mechanics and gameplay A deeper look at the mechanics and gameplay Mechanics Breakdown In Brief Players must connect buildings together by allocating resources in a resource chain across the map. They must reach and resolve their Objective within a given number of turns to succeed. To accomplish this, they have the following tools at their disposal: Linking Connect buildings together by allocating resources from buildings that produce them to buildings

  14. Mechanisms of gas precipitation in plasma-exposed tungsten

    SciTech Connect (OSTI)

    R. D. Kolasinski; D. F. Cowgill; D. C. Donovan; M. Shimada

    2012-05-01

    Precipitation in subsurface bubbles is a key process that governs how hydrogen isotopes migrate through and become trapped within plasma-exposed tungsten. We describe a continuum-scale model of hydrogen diffusion in plasma-exposed materials that includes the effects of precipitation. The model can account for bubble expansion via dislocation loop punching, using an accurate equation of state to determine the internal pressure. This information is used to predict amount of hydrogen trapped by bubbles, as well as the conditions where the bubbles become saturated. In an effort to validate the underlying assumptions, we compare our results with published positron annihilation and thermal desorption spectroscopy data, as well as our own measurements using the tritium plasma experiment (TPE).

  15. A Nonlocal Peridynamic Plasticity Model for the Dynamic Flow and Fracture of Concrete.

    SciTech Connect (OSTI)

    Vogler, Tracy; Lammi, Christopher James

    2014-10-01

    A nonlocal, ordinary peridynamic constitutive model is formulated to numerically simulate the pressure-dependent flow and fracture of heterogeneous, quasi-brittle ma- terials, such as concrete. Classical mechanics and traditional computational modeling methods do not accurately model the distributed fracture observed within this family of materials. The peridynamic horizon, or range of influence, provides a characteristic length to the continuum and limits localization of fracture. Scaling laws are derived to relate the parameters of peridynamic constitutive model to the parameters of the classical Drucker-Prager plasticity model. Thermodynamic analysis of associated and non-associated plastic flow is performed. An implicit integration algorithm is formu- lated to calculate the accumulated plastic bond extension and force state. The gov- erning equations are linearized and the simulation of the quasi-static compression of a cylinder is compared to the classical theory. A dissipation-based peridynamic bond failure criteria is implemented to model fracture and the splitting of a concrete cylinder is numerically simulated. Finally, calculation of the impact and spallation of a con- crete structure is performed to assess the suitability of the material and failure models for simulating concrete during dynamic loadings. The peridynamic model is found to accurately simulate the inelastic deformation and fracture behavior of concrete during compression, splitting, and dynamically induced spall. The work expands the types of materials that can be modeled using peridynamics. A multi-scale methodology for simulating concrete to be used in conjunction with the plasticity model is presented. The work was funded by LDRD 158806.

  16. Attempt to extract the preformation probability of. cap alpha. cluster at the surface of heavy nuclei by means of. cap alpha. -transfer reactions leading to the continuum states

    SciTech Connect (OSTI)

    Xu Shu-wei; Wu Guo-hua; Miao Rong-zhi; Han Fei

    1983-07-01

    The method of parametrization of an EFR-DWBA overlap integral developed by T. Udagawa and T. Tamura et al./sup 1/ is improved. Using the improved method we have fitted the experimental double differential energy spectrum of the /sup 8/Be cluster coming from the reaction /sup 208/Pb(/sup 12/C, /sup 8/Be) /sup 212/Po leading to the continuum states and extracted the preformation probability of the ..cap alpha.. cluster at the surface of the /sup 212/Po nucleus. Within the range of calculation error, the result is in agreement with that extracted from fitting the experimental data of ..cap alpha.. decay.

  17. Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Granular

    Office of Environmental Management (EM)

    Salt Consolidation, Constitutive Model and Micromechanics | Department of Energy Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Granular Salt Consolidation, Constitutive Model and Micromechanics Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Granular Salt Consolidation, Constitutive Model and Micromechanics The report addresses granular salt reconsolidation from three vantage points: laboratory testing, modeling, and petrofabrics. The experimental data 1)

  18. Internal pipe attachment mechanism

    DOE Patents [OSTI]

    Bast, Richard M. (Livermore, CA); Chesnut, Dwayne A. (Pleasanton, CA); Henning, Carl D. (Livermore, CA); Lennon, Joseph P. (Livermore, CA); Pastrnak, John W. (Livermore, CA); Smith, Joseph A. (Livermore, CA)

    1994-01-01

    An attachment mechanism for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection.

  19. Internal pipe attachment mechanism

    DOE Patents [OSTI]

    Bast, R.M.; Chesnut, D.A.; Henning, C.D.; Lennon, J.P.; Pastrnak, J.W.; Smith, J.A.

    1994-12-13

    An attachment mechanism is described for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection. 6 figures.

  20. Negative hydrogen ion production mechanisms

    SciTech Connect (OSTI)

    Bacal, M.; Wada, M.

    2015-06-15

    Negative hydrogen/deuterium ions can be formed by processes occurring in the plasma volume and on surfaces facing the plasma. The principal mechanisms leading to the formation of these negative ions are dissociative electron attachment to ro-vibrationally excited hydrogen/deuterium molecules when the reaction takes place in the plasma volume, and the direct electron transfer from the low work function metal surface to the hydrogen/deuterium atoms when formation occurs on the surface. The existing theoretical models and reported experimental results on these two mechanisms are summarized. Performance of the negative hydrogen/deuterium ion sources that emerged from studies of these mechanisms is reviewed. Contemporary negative ion sources do not have negative ion production electrodes of original surface type sources but are operated with caesium with their structures nearly identical to volume production type sources. Reasons for enhanced negative ion current due to caesium addition to these sources are discussed.

  1. Towards consistent nuclear models and comprehensive nuclear data

    Office of Scientific and Technical Information (OSTI)

    evaluations (Conference) | SciTech Connect Conference: Towards consistent nuclear models and comprehensive nuclear data evaluations Citation Details In-Document Search Title: Towards consistent nuclear models and comprehensive nuclear data evaluations The essence of this paper is to enlighten the consistency achieved nowadays in nuclear data and uncertainties assessments in terms of compound nucleus reaction theory from neutron separation energy to continuum. Making the continuity of

  2. Cracked-fuel mechanics. [PWR; BWR

    SciTech Connect (OSTI)

    Williford, R.E.; Lanning, D.D.

    1982-01-01

    This paper presents a modelling concept and a set of measurable parameters that have been shown to improve the prediction of the mechanical behavior of cracked fuel/cladding systems without added computational expense. The transition from classical annular gap/cylindrical pellet models to modified bulk properties and further to local behavior for cracked fuel systems is discussed. The results of laboratory experiments to verify these modelling parameters are shown. Data are also presented from laboratory experiments on unirradiated and irradiated rods which show that fuel rod mechanical response depends on fuel fragment size. The impact of these data on cracked fuel behavior and failure modelling is also discussed.

  3. Mechanical seal assembly

    DOE Patents [OSTI]

    Kotlyar, Oleg M. (Salt Lake City, UT)

    2002-01-01

    An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transfering it to the mechanical diode.

  4. Mechanical seal assembly

    DOE Patents [OSTI]

    Kotlyar, Oleg M. (Salt Lake City, UT)

    2001-01-01

    An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transferring it to the mechanical diode.

  5. Monroe Thomas, Mechanical Technician

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and endstation moves. Though he's training another mechanical technician to operate the crane, it's Monroe who is called upon for critical moves. He plays a key role in...

  6. Documentation of Hybrid Hydride Model for Incorporation into Moose-Bison and Validation Strategy.

    SciTech Connect (OSTI)

    Weck, Philippe F; Tikare, Veena; Schultz, Peter Andrew; Clark, B; Mitchell, J; Glazoff, Michael V.; Homer, Eric R.

    2014-10-01

    This report documents the development, demonstration and validation of a mesoscale, microstructural evolution model for simulation of zirconium hydride ?-ZrH{sub 1.5} precipitation in the cladding of used nuclear fuels that may occur during long-term dry storage. While the Zr-based claddings are manufactured free of any hydrogen, they absorb hydrogen during service, in the reactor by a process commonly termed hydrogen pick-up. The precipitation and growth of zirconium hydrides during dry storage is one of the most likely fuel rod integrity failure mechanisms either by embrittlement or delayed hydride cracking of the cladding (Hanson et al., 2011). While the phenomenon is well documented and identified as a potential key failure mechanism during long-term dry storage (Birk et al., 2012 and NUREG/CR-7116), the ability to actually predict the formation of hydrides is poor. The model being documented in this work is a computational capability for the prediction of hydride formation in different claddings of used nuclear fuels. This work supports the Used Fuel Disposition Research and Development Campaign in assessing the structural engineering performance of the cladding during and after long-term dry storage. In this work, a model to numerically simulate hydride precipitation at the microstructural scale, in a wide variety of Zr-based claddings, under dry-storage conditions is being developed. It will be used to aid in the evaluation of the mechanical integrity of used fuel rods during dry storage and transportation by providing the structural conditions from the microstructural scale to the continuum scale to engineering component scale models to predict if the used fuel rods will perform without failure under normal and off-normal conditions. The microstructure, especially, the hydride structure is thought to be a primary determinant of cladding failure, thus this component of UFDs storage and transportation analysis program is critical. The model development, application and validation of the model are documented and the limitations of the current model are discussed. The model has been shown to simulate hydride precipitation in Zircaloy-4 cladding with correct morphology, thermodynamics and kinetics. An unexpected insight obtained from simulations hydride formation in Zircaloy-4 is that small (sub-micron) precipitates need to order themselves to form the larger hydrides typically described as radially-reoriented precipitates. A limitation of this model is that it does not currently solve the stress state that forms dynamically in the precipitate or matrix surrounding the precipitate. A method to overcome the limitations is suggested and described in detail. The necessary experiments to provide key materials physics and to validate the model are also recommended.

  7. Mechanical code comparator

    DOE Patents [OSTI]

    Peter, Frank J.; Dalton, Larry J.; Plummer, David W.

    2002-01-01

    A new class of mechanical code comparators is described which have broad potential for application in safety, surety, and security applications. These devices can be implemented as micro-scale electromechanical systems that isolate a secure or otherwise controlled device until an access code is entered. This access code is converted into a series of mechanical inputs to the mechanical code comparator, which compares the access code to a pre-input combination, entered previously into the mechanical code comparator by an operator at the system security control point. These devices provide extremely high levels of robust security. Being totally mechanical in operation, an access control system properly based on such devices cannot be circumvented by software attack alone.

  8. Water versus DNA: New insights into proton track-structure modeling in radiobiology and radiotherapy

    SciTech Connect (OSTI)

    Champion, Christophe; Galassi, Mariel E.; Weck, Philippe F.; Fojon, Omar A.; Hanssen, Jocelyn; Rivarola, Roberto D.

    2015-09-25

    Water is a common surrogate of DNA for modelling the charged particle-induced ionizing processes in living tissue exposed to radiations. The present study aims at scrutinizing the validity of this approximation and then revealing new insights into proton-induced energy transfers by a comparative analysis between water and realistic biological medium. In this context, a self-consistent quantum mechanical modelling of the ionization and electron capture processes is reported within the continuum distorted wave-eikonal initial state framework for both isolated water molecules and DNA components impacted by proton beams. Their respective probability of occurrence-expressed in terms of total cross sections-as well as their energetic signature (potential and kinetic) are assessed in order to clearly emphasize the differences existing between realistic building blocks of living matter and the controverted water-medium surrogate. Thus the consequences in radiobiology and radiotherapy will be discussed in particular in view of treatment planning refinement aiming at better radiotherapy strategies.

  9. Water versus DNA: New insights into proton track-structure modeling in radiobiology and radiotherapy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Champion, Christophe; Quinto, Michele A.; Monti, Juan M.; Galassi, Mariel E.; Weck, Philippe F.; Fojon, Omar A.; Hanssen, Jocelyn; Rivarola, Roberto D.

    2015-09-25

    Water is a common surrogate of DNA for modelling the charged particle-induced ionizing processes in living tissue exposed to radiations. The present study aims at scrutinizing the validity of this approximation and then revealing new insights into proton-induced energy transfers by a comparative analysis between water and realistic biological medium. In this context, a self-consistent quantum mechanical modelling of the ionization and electron capture processes is reported within the continuum distorted wave-eikonal initial state framework for both isolated water molecules and DNA components impacted by proton beams. Their respective probability of occurrence-expressed in terms of total cross sections-as well asmore » their energetic signature (potential and kinetic) are assessed in order to clearly emphasize the differences existing between realistic building blocks of living matter and the controverted water-medium surrogate. Thus the consequences in radiobiology and radiotherapy will be discussed in particular in view of treatment planning refinement aiming at better radiotherapy strategies.« less

  10. Training and Research on Probabilistic Hydro-Thermo-Mechanical...

    Office of Scientific and Technical Information (OSTI)

    Training and Research on Probabilistic Hydro-Thermo-Mechanical Modeling of Carbon Dioxide ... Citation Details In-Document Search Title: Training and Research on Probabilistic ...

  11. Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms: Tools for Physics-Based Model Development. Citation Details In-Document Search Title: ...

  12. Rotary mechanical latch

    DOE Patents [OSTI]

    Spletzer, Barry L.; Martinez, Michael A.; Marron, Lisa C.

    2012-11-13

    A rotary mechanical latch for positive latching and unlatching of a rotary device with a latchable rotating assembly having a latching gear that can be driven to latched and unlatched states by a drive mechanism such as an electric motor. A cam arm affixed to the latching gear interfaces with leading and trailing latch cams affixed to a flange within the drive mechanism. The interaction of the cam arm with leading and trailing latch cams prevents rotation of the rotating assembly by external forces such as those due to vibration or tampering.

  13. Electronic door locking mechanism

    DOE Patents [OSTI]

    Williams, G.L.; Kirby, P.G.

    1997-10-21

    The invention is a motorized linkage for engaging a thumb piece in a door mechanism. The device has an exterior lock assembly with a small battery cell and combination lock. Proper entry by a user of a security code allows the battery to operate a small motor within the exterior lock assembly. The small motor manipulates a cam-plunger which moves an actuator pin into a thumb piece. The user applies a force on to the thumb piece. This force is transmitted by the thumb piece to a latch engagement mechanism by the actuator pin. The latch engagement mechanism operates the door latch. 6 figs.

  14. Electronic door locking mechanism

    DOE Patents [OSTI]

    Williams, Gary Lin; Kirby, Patrick Gerald

    1997-01-01

    The invention is a motorized linkage for engaging a thumb piece in a door mechanism. The device has an exterior lock assembly with a small battery cell and combination lock. Proper entry by a user of a security code allows the battery to operate a small motor within the exterior lock assembly. The small motor manipulates a cam-plunger which moves an actuator pin into a thumb piece. The user applies a force on to the thumb piece. This force is transmitted by the thumb piece to a latch engagement mechanism by the actuator pin. The latch engagement mechanism operates the door latch.

  15. How reclamation tests mechanical governors

    SciTech Connect (OSTI)

    Agee, J.C.; Girgis, G.K.; Cline, R.

    1996-08-01

    The Bureau of Reclamation has developed its own equipment for testing mechanical-hydraulic governors for hydroelectric generators. The device, called a Permanent Magnet Generator (PMG) Simulator, generates a three-phase voltage that will drive the governor ballhead motor at variable speed. Utilizing this equipment, most traditional governor tests can be completed with the generating unit dewatered. In addition, frequency response testing and other detailed analytical tests can be performed to validate governor models. This article describes the development and design of the equipment, and it also discusses its usage in a case study of events at Glen Canyon Dam.

  16. Mechanical accessories for mobile teleoperators

    SciTech Connect (OSTI)

    Feldman, M.J.; Herndon, J.N.

    1985-01-01

    The choice of optimum mechanical accessories for mobile teleoperators involves matching the criteria for emergency response with the available technology. This paper presents a general background to teleoperations, a potpourri of the manipulator systems available, and an argument for force reflecting manipulation. The theme presented is that the accomplishment of humanlike endeavors in hostile environments will be most successful when man model capabilities are utilized. The application of recent electronic technology to manipulator development has made new tools available to be applied to emergency response activities. The development activities described are products of the Consolidated Fuel Reprocessing Program at the Oak Ridge National Laboratory. 13 refs., 7 figs.

  17. Derivation of effective fission gas diffusivities in UO2 from lower length scale simulations and implementation of fission gas diffusion models in BISON

    SciTech Connect (OSTI)

    Andersson, Anders David Ragnar; Pastore, Giovanni; Liu, Xiang-Yang; Perriot, Romain Thibault; Tonks, Michael; Stanek, Christopher Richard

    2014-11-07

    This report summarizes the development of new fission gas diffusion models from lower length scale simulations and assessment of these models in terms of annealing experiments and fission gas release simulations using the BISON fuel performance code. Based on the mechanisms established from density functional theory (DFT) and empirical potential calculations, continuum models for diffusion of xenon (Xe) in UO2 were derived for both intrinsic conditions and under irradiation. The importance of the large XeU3O cluster (a Xe atom in a uranium + oxygen vacancy trap site with two bound uranium vacancies) is emphasized, which is a consequence of its high mobility and stability. These models were implemented in the MARMOT phase field code, which is used to calculate effective Xe diffusivities for various irradiation conditions. The effective diffusivities were used in BISON to calculate fission gas release for a number of test cases. The results are assessed against experimental data and future directions for research are outlined based on the conclusions.

  18. Phase Field Fracture Mechanics.

    SciTech Connect (OSTI)

    Robertson, Brett Anthony

    2015-11-01

    For this assignment, a newer technique of fracture mechanics using a phase field approach, will be examined and compared with experimental data for a bend test and a tension test. The software being used is Sierra Solid Mechanics, an implicit/explicit finite element code developed at Sandia National Labs in Albuquerque, New Mexico. The bend test experimental data was also obtained at Sandia Labs while the tension test data was found in a report online from Purdue University.

  19. computational-structural-mechanics-student-thesis

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Structural Mechanics Student Thesis Abstract NUMERICAL MODELING OF STAY CABLES AND STAY CABLE BRIDGES The Computational Structural Mechanics staff at TRACC is supporting two students from Northern Illinois University who are working for a Masters degree. The CSM staff is directing the thesis research and working with them on two projects: (1) cable-stay bridge vibrations due to traffic loading and (2) aerodynamic loading on stay cables. During this quarter, Srihari Vannemreddi successfully

  20. Training and Research on Probabilistic Hydro-Thermo-Mechanical...

    Office of Scientific and Technical Information (OSTI)

    models of the subsurface to forecast CO2 behavior and transport; optimize site operational ... GS; 2) models for the hydro-mechanical behavior of fractured porous rocks with random ...

  1. Atomistic modeling of nanowires, small-scale fatigue damage in cast magnesium, and materials for MEMS.

    SciTech Connect (OSTI)

    Dunn, Martin L.; Talmage, Mellisa J.; McDowell, David L., 1956- (,-Georgia Institute of Technology, Atlanta, GA); West, Neil (University of Colorado, Boulder, CO); Gullett, Philip Michael (Mississippi State University , MS); Miller, David C. (University of Colorado, Boulder, CO); Spark, Kevin (University of Colorado, Boulder, CO); Diao, Jiankuai (University of Colorado, Boulder, CO); Horstemeyer, Mark F. (Mississippi State University , MS); Zimmerman, Jonathan A.; Gall, K

    2006-10-01

    Lightweight and miniaturized weapon systems are driving the use of new materials in design such as microscale materials and ultra low-density metallic materials. Reliable design of future weapon components and systems demands a thorough understanding of the deformation modes in these materials that comprise the components and a robust methodology to predict their performance during service or storage. Traditional continuum models of material deformation and failure are not easily extended to these new materials unless microstructural characteristics are included in the formulation. For example, in LIGA Ni and Al-Si thin films, the physical size is on the order of microns, a scale approaching key microstructural features. For a new potential structural material, cast Mg offers a high stiffness-to-weight ratio, but the microstructural heterogeneity at various scales requires a structure-property continuum model. Processes occurring at the nanoscale and microscale develop certain structures that drive material behavior. The objective of the work presented in this report was to understand material characteristics in relation to mechanical properties at the nanoscale and microscale in these promising new material systems. Research was conducted primarily at the University of Colorado at Boulder to employ tightly coupled experimentation and simulation to study damage at various material size scales under monotonic and cyclic loading conditions. Experimental characterization of nano/micro damage will be accomplished by novel techniques such as in-situ environmental scanning electron microscopy (ESEM), 1 MeV transmission electron microscopy (TEM), and atomic force microscopy (AFM). New simulations to support experimental efforts will include modified embedded atom method (MEAM) atomistic simulations at the nanoscale and single crystal micromechanical finite element simulations. This report summarizes the major research and development accomplishments for the LDRD project titled 'Atomistic Modeling of Nanowires, Small-scale Fatigue Damage in Cast Magnesium, and Materials for MEMS'. This project supported a strategic partnership between Sandia National Laboratories and the University of Colorado at Boulder by providing funding for the lead author, Ken Gall, and his students, while he was a member of the University of Colorado faculty.

  2. PHASE STRUCTURE OF TWISTED EGUCHI-KAWAI MODEL.

    SciTech Connect (OSTI)

    ISHIKAWA,T.; AZEYANAGI, T.; HANADA, M.; HIRATA, T.

    2007-07-30

    We study the phase structure of the four-dimensional twisted Eguchi-Kawai model using numerical simulations. This model is an effective tool for studying SU(N) gauge theory in the large-N limit and provides a nonperturbative formulation of the gauge theory on noncommutative spaces. Recently it was found that its Z{sub n}{sup 4} symmetry, which is crucial for the validity of this model, can break spontaneously in the intermediate coupling region. We investigate in detail the symmetry breaking point from the weak coupling side. Our simulation results show that the continuum limit of this model cannot be taken.

  3. Mechanism of instantaneous coal outbursts

    SciTech Connect (OSTI)

    Guan, P.; Wang, H.Y.; Zhang, Y.X.

    2009-10-15

    Thousands of mine workers die every year from mining accidents, and instantaneous coal outbursts in underground coal mines are one of the major killers. Various models for these outbursts have been proposed, but the precise mechanism is still unknown. We hypothesize that the mechanism of coal outbursts is similar to magma fragmentation during explosive volcanic eruptions; i.e., it is caused by high gas pressure inside coal but low ambient pressure on it, breaking coal into pieces and releasing the high-pressure gas in a shock wave. Hence, coal outbursts may be regarded as another type of gas-driven eruption, in addition to explosive volcanic, lake, and possible ocean eruptions. We verify the hypothesis by experiments using a shock-tube apparatus. Knowing the mechanism of coal outbursts is the first step in developing prediction and mitigation measures. The new concept of gas-driven solid eruption is also important to a better understanding of salt-gas outbursts, rock-gas outbursts, and mud volcano eruptions.

  4. Question of universality in RP{sup {ital n}{minus}1} and O({ital n}) lattice {sigma} models

    SciTech Connect (OSTI)

    Niedermayer, F.; Weisz, P.; Shin, D.

    1996-05-01

    We argue that there is no essential violation of universality in the continuum limit of mixed RP{sup {ital n}{minus}1} and O({ital n}) lattice {sigma} models in two dimensions, contrary to opposite claims in the literature. {copyright} {ital 1996 The American Physical Society.}

  5. PHYSICAL PROPERTIES OF SPECTROSCOPICALLY CONFIRMED GALAXIES AT z {>=} 6. II. MORPHOLOGY OF THE REST-FRAME UV CONTINUUM AND Ly{alpha} EMISSION

    SciTech Connect (OSTI)

    Jiang Linhua; Windhorst, Rogier A.; Cohen, Seth H.; Mechtley, Matthew; Egami, Eiichi; Fan Xiaohui; Dave, Romeel; Finlator, Kristian; Kashikawa, Nobunari; Ouchi, Masami; Shimasaku, Kazuhiro

    2013-08-20

    We present a detailed structural and morphological study of a large sample of spectroscopically confirmed galaxies at z {>=} 6 using deep Hubble Space Telescope (HST) near-IR broad-band images and Subaru Telescope optical narrow-band images. The galaxy sample consists of 51 Ly{alpha} emitters (LAEs) at z {approx_equal} 5.7, 6.5, and 7.0, and 16 Lyman break galaxies (LBGs) at 5.9 {<=} z {<=} 6.5. These galaxies exhibit a wide range of rest-frame UV continuum morphology in the HST images, from compact features to multiple component systems. The fraction of merging/interacting galaxies reaches 40%-50% at the brightest end of M{sub 1500} {<=} -20.5 mag. The intrinsic half-light radii r{sub hl,in}, after correcting for point-spread function (PSF) broadening, are roughly between r{sub hl,in} {approx_equal} 0.''05 (0.3 kpc) and 0.''3 (1.7 kpc) at M{sub 1500} {<=} -19.5 mag. The median r{sub hl,in} value is 0.''16 ({approx}0.9 kpc). This is consistent with the sizes of bright LAEs and LBGs at z {>=} 6 found in previous studies. In addition, more luminous galaxies tend to be larger and exhibit a weak size-luminosity relation, r{sub hl,in}{proportional_to}L {sup 0.14} at M{sub 1500} {<=} -19.5 mag. The slope of 0.14 is significantly flatter than those in fainter LBG samples. We discuss the morphology of z {>=} 6 galaxies with nonparametric methods, including the concentration, asymmetry, and smoothness system and the Gini and M{sub 20} parameters, and demonstrate their validity through simulations. We search for extended Ly{alpha} emission halos around LAEs at z {approx_equal} 5.7 and 6.5 by stacking a number of narrow-band images. We do not find evidence of extended Ly{alpha} halos predicted by cosmological simulations. Such halos, if they exist, could be weaker than predicted. Finally, we investigate positional misalignment between the UV continuum and Ly{alpha} emissions in LAEs. While the two positions are generally consistent, several merging galaxies show significant positional differences. This is likely caused by a disturbed interstellar medium distribution due to merging activity.

  6. PHYSICAL PROPERTIES OF SPECTROSCOPICALLY CONFIRMED GALAXIES AT z {>=} 6. I. BASIC CHARACTERISTICS OF THE REST-FRAME UV CONTINUUM AND Ly{alpha} EMISSION

    SciTech Connect (OSTI)

    Jiang Linhua; Mechtley, Matthew; Cohen, Seth H.; Windhorst, Rogier A.; Egami, Eiichi; Fan Xiaohui; Dave, Romeel; Finlator, Kristian; Kashikawa, Nobunari; Ouchi, Masami; Shimasaku, Kazuhiro

    2013-08-01

    We present deep Hubble Space Telescope near-IR and Spitzer mid-IR observations of a large sample of spectroscopically confirmed galaxies at z {>=} 6. The sample consists of 51 Ly{alpha} emitters (LAEs) at z {approx_equal} 5.7, 6.5, and 7.0, and 16 Lyman break galaxies (LBGs) at 5.9 {<=} z {<=} 6.5. The near-IR images were mostly obtained with WFC3 in the F125W and F160W bands, and the mid-IR images were obtained with IRAC in the 3.6 {mu}m and 4.5 {mu}m bands. Our galaxies also have deep optical imaging data from Subaru Suprime-Cam. We utilize the multi-band data and secure redshifts to derive their rest-frame UV properties. These galaxies have steep UV-continuum slopes roughly between {beta} {approx_equal} -1.5 and -3.5, with an average value of {beta} {approx_equal} -2.3, slightly steeper than the slopes of LBGs in previous studies. The slope shows little dependence on UV-continuum luminosity except for a few of the brightest galaxies. We find a statistically significant excess of galaxies with slopes around {beta} {approx_equal} -3, suggesting the existence of very young stellar populations with extremely low metallicity and dust content. Our galaxies have moderately strong rest-frame Ly{alpha} equivalent width (EW) in a range of {approx}10 to {approx}200 A. The star formation rates are also moderate, from a few to a few tens of solar masses per year. The LAEs and LBGs in this sample share many common properties, implying that LAEs represent a subset of LBGs with strong Ly{alpha} emission. Finally, the comparison of the UV luminosity functions between LAEs and LBGs suggests that there exists a substantial population of faint galaxies with weak Ly{alpha} emission (EW < 20 A) that could be the dominant contribution to the total ionizing flux at z {>=} 6.

  7. A DEEP HUBBLE SPACE TELESCOPE SEARCH FOR ESCAPING LYMAN CONTINUUM FLUX AT z {approx} 1.3: EVIDENCE FOR AN EVOLVING IONIZING EMISSIVITY

    SciTech Connect (OSTI)

    Siana, Brian; Bridge, Carrie R.; Teplitz, Harry I.; Chary, Ranga-Ram; Colbert, James W.; Scarlata, Claudia; Ferguson, Henry C.; Brown, Thomas M.; Giavalisco, Mauro; Dickinson, Mark; De Mello, Duilia F.; Conselice, Christopher J.; Gardner, Jonathan P.

    2010-11-01

    We have obtained deep Hubble Space Telescope far-UV images of 15 starburst galaxies at z {approx} 1.3 in the GOODS fields to search for escaping Lyman continuum (LyC) photons. These are the deepest far-UV images (m{sub AB} = 28.7, 3{sigma}, 1'' diameter) over this large an area (4.83 arcmin{sup 2}) and provide some of the best escape fraction constraints for any galaxies at any redshift. We do not detect any individual galaxies, with 3{sigma} limits to the LyC ({approx}700 A) flux 50-149 times fainter (in f{sub {nu}}) than the rest-frame UV (1500 A) continuum fluxes. Correcting for the mean intergalactic medium (IGM) attenuation (factor {approx}2), as well as an intrinsic stellar Lyman break (factor {approx}3), these limits translate to relative escape fraction limits of f{sub esc,rel} < [0.03, 0.21]. The stacked limit is f{sub esc,rel}(3{sigma}) < 0.02. We use a Monte Carlo simulation to properly account for the expected distribution of line-of-sight IGM opacities. When including constraints from previous surveys at z {approx} 1.3 we find that, at the 95% confidence level, no more than 8% of star-forming galaxies at z {approx} 1.3 can have relative escape fractions greater than 0.50. Alternatively, if the majority of galaxies have low, but non-zero, escaping LyC, the escape fraction cannot be more than 0.04. In light of some evidence for strong LyC emission from UV-faint regions of Lyman break galaxies (LBGs) at z {approx} 3, we also stack sub-regions of our galaxies with different surface brightnesses and detect no significant LyC flux at the f{sub esc,rel} < 0.03 level. Both the stacked limits and the limits from the Monte Carlo simulation suggest that the average ionizing emissivity (relative to non-ionizing UV emissivity) at z {approx} 1.3 is significantly lower than has been observed in LBGs at z {approx} 3. If the ionizing emissivity of star-forming galaxies is in fact increasing with redshift, it would help to explain the high photoionization rates seen in the IGM at z>4 and reionization of the IGM at z>6.

  8. PNNL Technical Support to The Implementation of EMTA and EMTA-NLA Models in Autodesk Moldflow Packages

    SciTech Connect (OSTI)

    Nguyen, Ba Nghiep; Wang, Jin

    2012-12-01

    Under the Predictive Engineering effort, PNNL developed linear and nonlinear property prediction models for long-fiber thermoplastics (LFTs). These models were implemented in PNNLs EMTA and EMTA-NLA codes. While EMTA is a standalone software for the computation of the composites thermoelastic properties, EMTA-NLA presents a series of nonlinear models implemented in ABAQUS via user subroutines for structural analyses. In all these models, it is assumed that the fibers are linear elastic while the matrix material can exhibit a linear or typical nonlinear behavior depending on the loading prescribed to the composite. The key idea is to model the constitutive behavior of the matrix material and then to use an Eshelby-Mori-Tanaka approach (EMTA) combined with numerical techniques for fiber length and orientation distributions to determine the behavior of the as-formed composite. The basic property prediction models of EMTA and EMTA-NLA have been subject for implementation in the Autodesk Moldflow software packages. These models are the elastic stiffness model accounting for fiber length and orientation distributions, the fiber/matrix interface debonding model, and the elastic-plastic models. The PNNL elastic-plastic models for LFTs describes the composite nonlinear stress-strain response up to failure by an elastic-plastic formulation associated with either a micromechanical criterion to predict failure or a continuum damage mechanics formulation coupling damage to plasticity. All the models account for fiber length and orientation distributions as well as fiber/matrix debonding that can occur at any stage of loading. In an effort to transfer the technologies developed under the Predictive Engineering project to the American automotive and plastics industries, PNNL has obtained the approval of the DOE Office of Vehicle Technologies to provide Autodesk, Inc. with the technical support for the implementation of the basic property prediction models of EMTA and EMTA-NLA in the Autodesk Moldflow packages. This report summarizes the recent results from Autodesk Simulation Moldlow Insight (ASMI) analyses using the EMTA models and EMTA-NLA/ABAQUS analyses for further assessment of the EMTA-NLA models to support their implementation in Autodesk Moldflow Structural Alliance (AMSA). PNNLs technical support to Autodesk, Inc. included (i) providing the theoretical property prediction models as described in published journal articles and reports, (ii) providing explanations of these models and computational procedure, (iii) providing the necessary LFT data for process simulations and property predictions, and (iv) performing ABAQUS/EMTA-NLA analyses to further assess and illustrate the models for selected LFT materials.

  9. FAQS Reference Guide - Mechanical Systems | Department of Energy

    Office of Environmental Management (EM)

    Mechanical Systems FAQS Reference Guide - Mechanical Systems This reference guide has been developed to address the competency statements in the June 2008 edition of DOE-STD-1161-2008, Mechanical Systems Functional Area Qualification Standard. PDF icon Mechanical Systems Qualification Standard Reference Guide, August 2012 More Documents & Publications DOE-HDBK-1017/1-93 A Review of Stress Corrosion Cracking/Fatigue Modeling for Light Water Reactor Cooling System Components DOE-HDBK-1017

  10. Fundamental mechanisms in flue gas conditioning

    SciTech Connect (OSTI)

    Bush, P.V.; Snyder, T.R.

    1992-01-09

    The overall goal of this research project is to formulate a mathematical model of flue gas conditioning. This model will be based on an understanding of why ask properties, such as cohesivity and resistivity, are changed by conditioning. Such a model could serve as a component of the performance models of particulate control devices where flue gas conditioning is used. There are two specific objectives of this research project, which divide the planned research into two main parts. One part of the project is designed to determine how ash particles are modified by interactions with sorbent injection processes and to describe the mechanisms by which these interactions affect fine particle collection. The objective of the other part of the project is to identify the mechanisms by which conditioning agents, including chemically active compounds, modify the key properties of fine fly ash particles.

  11. High dynamic range measurement of spectral responsivity and linearity of a radiation thermometer using a super-continuum laser and LEDs

    SciTech Connect (OSTI)

    Yoo, Y. S.; Lee, D. H.; Park, C. W.; Park, S. N. [Korea Research Institute of Standards and Science 209 Gajeong-Ro, Yuseong-Gu, Daejon 305-340 (Korea, Republic of)] [Korea Research Institute of Standards and Science 209 Gajeong-Ro, Yuseong-Gu, Daejon 305-340 (Korea, Republic of)

    2013-09-11

    To realize the temperature scale above the freezing point of silver according to the definition of ITS-90, the dynamic range of the spectral responsivity is one of the most important factors which limit its uncertainty. When the residual spectral response at both side bands of a spectral band is not negligible, a significant uncertainty can be caused by a low dynamic range of the spectral responsivity measurement. In general, incandescent lamps are used to measure the spectral responsivity and the linearity. The dynamic range of the spectral responsivity measurement is often limited by a trade-off with the desired spectral resolution, which is less than 6 decades. Nonlinearity is another limiting fact of uncertainties of the temperature scale. Tungsten lamps have disadvantage in the nonlinearity measurements in terms of adjustability of radiance level and spectral selectivity. We report spectral responsivity measurements of which the measurable dynamic range is enhanced 50 times after replacing a QTH lamp with a super continuum laser. We also present a spectrally selected linearity measurement over a wide dynamic range using high-brightness light emitting diode arrays to observe a slight saturation of linearity.

  12. The mystery of spectral breaks: Lyman continuum absorption by photon-photon pair production in the Fermi GeV spectra of bright blazars

    SciTech Connect (OSTI)

    Stern, Boris E. [Institute for Nuclear Research, Russian Academy of Sciences, Prospekt 60-letiya Oktyabrya 7a, Moscow 117312 (Russian Federation); Poutanen, Juri, E-mail: stern.boris@gmail.com, E-mail: juri.poutanen@utu.fi [Tuorla Observatory, University of Turku, Vislntie 20, FI-21500 Piikki (Finland)

    2014-10-10

    We re-analyze Fermi/LAT ?-ray spectra of bright blazars using the new Pass 7 version of the detector response files and detect breaks at ?5 GeV in the rest-frame spectra of 3C 454.3 and possibly also 4C +21.35, associated with the photon-photon pair production absorption by the He II Lyman continuum (LyC). We also detect significant breaks at ?20 GeV associated with hydrogen LyC in both the individual spectra and the stacked redshift-corrected spectrum of several bright blazars. The detected breaks in the stacked spectra univocally prove that they are associated with atomic ultraviolet emission features of the quasar broad-line region (BLR). The dominance of the absorption by the hydrogen Ly complex over He II, a small detected optical depth, and break energy consistent with head-on collisions with LyC photons imply that the ?-ray emission site is located within the BLR, but most of the BLR emission comes from a flat disk-like structure producing little opacity. Alternatively, the LyC emission region size might be larger than the BLR size measured from reverberation mapping, and/or the ?-ray emitting region is extended. These solutions would resolve the long-standing issue of how the multi-hundred GeV photons can escape from the emission zone without being absorbed by softer photons.

  13. Modeling Lithium Ion Battery Safety: Venting of Pouch Cells; NREL (National Renewable Energy Laboratory)

    SciTech Connect (OSTI)

    Santhanagopalan, Shriram.; Yang, Chuanbo.; Pesaran, Ahmad

    2013-07-01

    This report documents the successful completion of the NREL July milestone entitled Modeling Lithium-Ion Battery Safety - Complete Case-Studies on Pouch Cell Venting, as part of the 2013 Vehicle Technologies Annual Operating Plan with the U.S. Department of Energy (DOE). This work aims to bridge the gap between materials modeling, usually carried out at the sub-continuum scale, and the

  14. One- and two-dimensional Stirling machine simulation using experimentally generated reversing flow turbuulence models

    SciTech Connect (OSTI)

    Goldberg, L.F.

    1990-08-01

    The activities described in this report do not constitute a continuum but rather a series of linked smaller investigations in the general area of one- and two-dimensional Stirling machine simulation. The initial impetus for these investigations was the development and construction of the Mechanical Engineering Test Rig (METR) under a grant awarded by NASA to Dr. Terry Simon at the Department of Mechanical Engineering, University of Minnesota. The purpose of the METR is to provide experimental data on oscillating turbulent flows in Stirling machine working fluid flow path components (heater, cooler, regenerator, etc.) with particular emphasis on laminar/turbulent flow transitions. Hence, the initial goals for the grant awarded by NASA were, broadly, to provide computer simulation backup for the design of the METR and to analyze the results produced. This was envisaged in two phases: First, to apply an existing one-dimensional Stirling machine simulation code to the METR and second, to adapt a two-dimensional fluid mechanics code which had been developed for simulating high Rayleigh number buoyant cavity flows to the METR. The key aspect of this latter component was the development of an appropriate turbulence model suitable for generalized application to Stirling simulation. A final-step was then to apply the two-dimensional code to an existing Stirling machine for which adequate experimental data exist. The work described herein was carried out over a period of three years on a part-time basis. Forty percent of the first year`s funding was provided as a match to the NASA funds by the Underground Space Center, University of Minnesota, which also made its computing facilities available to the project at no charge.

  15. Thermo-mechanical characterization of silicone foams

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rangaswamy, Partha; Smith, Nickolaus A.; Cady, Carl M.; Lewis, Matthew W.

    2015-10-01

    Cellular solids such as elastomeric foams are used in many structural applications to absorb and dissipate energy, due to their light weight (low density) and high energy absorption capability. In this paper we will discuss foams derived from S5370, a silicone foam formulation developed by Dow Corning. In the application presented, the foam is consolidated into a cushion component of constant thickness but variable density. A mechanical material model developed by Lewis (2013), predicts material response, in part, as a function of relative density. To determine the required parameters for this model we have obtained the mechanical response in compressionmorefor ambient, cold and hot temperatures. The variable density cushion provided samples sufficient samples so that the effect of sample initial density on the mechanical response could be studied. The mechanical response data showed extreme sensitivity to relative density. We also observed at strains corresponding to 1 MPa a linear relationship between strain and initial density for all temperatures. Samples taken from parts with a history of thermal cycling demonstrated a stiffening response that was a function of temperature, with the trend of more stiffness as temperature increased above ambient. This observation is in agreement with the entropic effects on the thermo-mechanical behavior of silicone polymers. In this study, we present the experimental methods necessary for the development of a material model, the testing protocol, analysis of test data, and a discussion of load (stress) and gap (strain) as a function of sample initial densities and temperaturesless

  16. Thermo-mechanical characterization of silicone foams

    SciTech Connect (OSTI)

    Rangaswamy, Partha; Smith, Nickolaus A.; Cady, Carl M.; Lewis, Matthew W.

    2015-10-01

    Cellular solids such as elastomeric foams are used in many structural applications to absorb and dissipate energy, due to their light weight (low density) and high energy absorption capability. In this paper we will discuss foams derived from S5370, a silicone foam formulation developed by Dow Corning. In the application presented, the foam is consolidated into a cushion component of constant thickness but variable density. A mechanical material model developed by Lewis (2013), predicts material response, in part, as a function of relative density. To determine the required parameters for this model we have obtained the mechanical response in compression for ambient, cold and hot temperatures. The variable density cushion provided samples sufficient samples so that the effect of sample initial density on the mechanical response could be studied. The mechanical response data showed extreme sensitivity to relative density. We also observed at strains corresponding to 1 MPa a linear relationship between strain and initial density for all temperatures. Samples taken from parts with a history of thermal cycling demonstrated a stiffening response that was a function of temperature, with the trend of more stiffness as temperature increased above ambient. This observation is in agreement with the entropic effects on the thermo-mechanical behavior of silicone polymers. In this study, we present the experimental methods necessary for the development of a material model, the testing protocol, analysis of test data, and a discussion of load (stress) and gap (strain) as a function of sample initial densities and temperatures

  17. Experiments for foam model development and validation.

    SciTech Connect (OSTI)

    Bourdon, Christopher Jay; Cote, Raymond O.; Moffat, Harry K.; Grillet, Anne Mary; Mahoney, James F.; Russick, Edward Mark; Adolf, Douglas Brian; Rao, Rekha Ranjana; Thompson, Kyle Richard; Kraynik, Andrew Michael; Castaneda, Jaime N.; Brotherton, Christopher M.; Mondy, Lisa Ann; Gorby, Allen D.

    2008-09-01

    A series of experiments has 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. Rheology, reaction kinetics and density measurements complement the flow visualization. X-ray computed tomography (CT) is used to examine the cured foams to determine density gradients. These data provide input to a continuum level finite element model of the blowing process.

  18. Sierra Mechanics suite

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanics suite - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs Advanced Nuclear

  19. Eight plane IPND mechanical testing.

    SciTech Connect (OSTI)

    Zhao, A.; Guarino, V.; Wood, K.; Nephew, T.; Ayres, D.; Lee, A.; High Energy Physics; FNAL

    2008-03-18

    A mechanical test of an 8 plane IPND mechanical prototype, which was constructed using extrusions from the testing/tryout of the 16 cell prototype extrusion die in Argonne National Laboratory, was conducted. There were 4 vertical and 4 horizontal planes in this 8 plane IPND prototype. Each vertical plane had four 16 cell extrusions, while each horizontal plane had six 16 cell extrusions. Each plane was glued together using the formulation of Devcon adhesive, Devcon 60. The vertical extrusions used in the vertical planes shares the same dimensions as the horizontal extrusions in the horizontal planes with the average web thickness of 2.1 mm and the average wall thickness of 3.1 mm. This mechanical prototype was constructed with end-seals on the both ends of the vertical extrusions. The gaps were filled with epoxy between extrusions and end-seals. The overall dimension of IPND is 154.8 by 103.1 by 21.7 inches with the weight of approximately 1200 kg, as shown in a figure. Two similar mechanical tests of 3 layer and 11 layer prototypes have been done in order to evaluate the strength of the adhesive joint between extrusions in the NOvA detector. The test showed that the IPND prototype was able to sustain under the loading of weight of itself and scintillator. Two FEA models were built to verify the measurement data from the test. The prediction from FEA slice model seems correlated reasonably well to the test result, even under a 'rough' estimated condition for the wall thickness (from an untuned die) and an unknown property of 'garage type' extrusion. A full size of FEA 3-D model also agrees very well with the test data from strain gage readings. It is worthy to point out that the stress distribution of the structure is predominantly determined by the internal pressure, while the buckling stability relies more on the loading weight from the extrusions themselves and scintillate. Results of conducted internal pressure tests, including 3- cell, 11-cell and the IPND prototypes, have been correlated to the FEA analysis very well. The authors believe they have quite good understanding of response of the NOvA structures subjected to the internal pressure, while the understanding of buckling stability is far behind. Therefore, more effect should be laid to improve the buckling considering that the FEA analysis usually is not able accurately modeling the stability as good as the stress analysis. The IPND structure was mostly built using 'scrape' piece extrusions (whatever available in shop). Therefore, a future test should be more focus on by using a actual real extrusions, for example like Nova -27 (if a final choice is made) and extrusion from a tuned die (very important). The authors should/will repeat 11 layers test with an actual thicker piece for the vertical to verify the adhesive joint and similar large scale prototype with a symmetry case, either 9 or 11 layers with the dial indicator on the both side.

  20. Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms:

    Office of Scientific and Technical Information (OSTI)

    Tools for Physics-Based Model Development. (Technical Report) | SciTech Connect Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms: Tools for Physics-Based Model Development. Citation Details In-Document Search Title: Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms: Tools for Physics-Based Model Development. We present the results of an LDRD project to develop diagnostics to perform fundamental measurements of material properties during shock

  1. Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms:

    Office of Scientific and Technical Information (OSTI)

    Tools for Physics-Based Model Development. (Technical Report) | SciTech Connect Technical Report: Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms: Tools for Physics-Based Model Development. Citation Details In-Document Search Title: Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms: Tools for Physics-Based Model Development. × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office

  2. Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Modeling | Department of Energy 09 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon es_17_sastry.pdf More Documents & Publications Modeling-Thermo-electrochemistry, Capacity Degradation and Mechanics with SEI Layer Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined Electrodes Intercalation Kinetics and Ion Mobility in Electrode Materials for Advanced Lithium Ion

  3. STRUCTURAL AND MECHANICAL EFFECTS OF RADIATION EXPOSURE ON FILLED

    Office of Scientific and Technical Information (OSTI)

    ELASTOMERS - RECENT INSIGHTS FROM EXPERIMENTS AND MODELING (Conference) | SciTech Connect Conference: STRUCTURAL AND MECHANICAL EFFECTS OF RADIATION EXPOSURE ON FILLED ELASTOMERS - RECENT INSIGHTS FROM EXPERIMENTS AND MODELING Citation Details In-Document Search Title: STRUCTURAL AND MECHANICAL EFFECTS OF RADIATION EXPOSURE ON FILLED ELASTOMERS - RECENT INSIGHTS FROM EXPERIMENTS AND MODELING Authors: Maiti, A ; Weisgraber, T ; Gee, R ; Dinh, L ; Wilson, T ; Small, W ; Alviso, C ; Chinn, S ;

  4. Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms:

    Office of Scientific and Technical Information (OSTI)

    Tools for Physics-Based Model Development. (Technical Report) | SciTech Connect Technical Report: Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms: Tools for Physics-Based Model Development. Citation Details In-Document Search Title: Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms: Tools for Physics-Based Model Development. We present the results of an LDRD project to develop diagnostics to perform fundamental measurements of material properties

  5. Fracture mechanics: 26. volume

    SciTech Connect (OSTI)

    Reuter, W.G.; Underwood, J.H.; Newman, J.C. Jr.

    1995-12-31

    The original objective of these symposia was to promote technical interchange between researchers from the US and worldwide in the field of fracture. This objective was recently expanded to promote technical interchange between researchers in the field of fatigue and fracture. The symposium began with the Swedlow Memorial Lecture entitled ``Patterns and Perspectives in Applied Fracture Mechanics.`` The remaining 42 papers are divided into the following topical sections: Constraint crack initiation; Constraint crack growth; Weldments; Engineered materials; Subcritical crack growth; Dynamic loading; and Applications. Papers within the scope of the Energy Data Base have been processed separately.

  6. Mechanical Systems Qualification Standard

    Office of Environmental Management (EM)

    61-2008 June 2008 DOE STANDARD MECHANICAL SYSTEMS QUALIFICATION STANDARD DOE Defense Nuclear Facilities Technical Personnel U.S. Department of Energy AREA TRNG Washington, D.C. 20585 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. DOE-STD-1161-2008 ii This document is available on the Department of Energy Technical Standards Program Web Site at http://www.hss.energy.gov/nuclearsafety/techstds/ DOE-STD-1161-2008 iv INTENTIONALLY BLANK DOE-STD-1161-2008 v TABLE OF

  7. NREL: Continuum Magazine Home Page

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Solar Expertise-A Launch Pad to the Future NREL is speeding solar devices from the lab to utility-scale operation. Paint It Black: One-Step Etch Cuts Solar Cell Costs Paint...

  8. NREL: Continuum Magazine Home Page

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Help Bring Financing to Solar Projects NREL is helping remove barriers that prevent pension and mutual funds from investing in solar power. NREL's Winning Hand of Clean...

  9. NREL: Continuum Magazine Home Page

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CAEBAT collaboration targets EDV batteries with longer range and lifespan, at a lower cost. The Key to Greener Fleets The Key to Greener Fleets Leveraging state-of-the-art...

  10. NREL: Continuum Magazine Home Page

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    is making solar cost competitive with non-renewable energy. Reaping a Harvest of Hope 03 Reaping a Harvest of Hope Five years after a devastating tornado, Greensburg, Kansas...

  11. Dan Says - Continuum Magazine | NREL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dan Says NREL Analysis: Reimagining What's Possible for Clean Energy A headshot of a man in a suit, smiling. Dr. Dan Arvizu An objective, credible analysis capability has been part and parcel of NREL's mission from our inception as the Solar Energy Research Institute in 1977. Our founders understood the vital role of providing technology-neutral analysis to ensure that innovations developed in the lab fit the needs of the energy consumer. Today, NREL continues to develop tools that increase our

  12. NREL: Continuum Magazine Home Page

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to help move big ideas to market. Industry Growth Forum Cultivates Clean Energy Entrepreneurship Industry Growth Forum Cultivates Clean Energy Entrepreneurship NREL's Industry...

  13. NREL: Continuum Magazine Home Page

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Circuits Rewiring Algae's Catalytic Circuits Opening a promising avenue to increased biohydrogen production. IMM Solar Cell Shows Its Versatility IMM Solar Cell Shows Its...

  14. Damage mechanisms in PBT-GF30 under thermo-mechanical cyclic loading

    SciTech Connect (OSTI)

    Schaaf, A., E-mail: alexander.schaaf@de.bosch.com; De Monte, M., E-mail: alexander.schaaf@de.bosch.com; Hoffmann, C., E-mail: alexander.schaaf@de.bosch.com [Robert Bosch GmbH, Corporate Sector Research and Advance Engineering - Advance Production Technology 1 - Plastics Engineering (CR/APP), Postbox 1131, 71301 Waiblingen (Germany); Vormwald, M., E-mail: vormwald@wm.tu-darmstadt.de [Department of Material Science, Darmstadt University of Technology (Germany); Quaresimin, M., E-mail: marino.quaresimin@unipd.it [Department of Management and Engineering, University of Padova (Italy)

    2014-05-15

    The scope of this paper is the investigation of damage mechanisms at microscopic scale on a short glass fiber reinforced polybutylene terephthalate (PBT-GF30) under thermo-mechanical cyclic loading. In addition the principal mechanisms are verified through micro mechanical FE models. In order to investigate the fatigue behavior of the material both isothermal strain controlled fatigue (ISCF) tests at three different temperatures and thermo-mechanical fatigue (TMF) tests were conducted on plain and notched specimens, manufactured by injection molding. The goal of the work is to determine the damage mechanisms occurring under TMF conditions and to compare them with the mechanisms occurring under ISCF. For this reason fracture surfaces of TMF and ISCF samples loaded at different temperature levels were analyzed using scanning electron microscopy. Furthermore, specimens that failed under TMF were examined on microsections revealing insight into both crack initiation and crack propagation. The findings of this investigation give valuable information about the main damage mechanisms of PBT-GF30 under TMF loading and serve as basis for the development of a TMF life estimation methodology.

  15. PEBBLES Mechanics Simulation Speedup

    SciTech Connect (OSTI)

    Joshua J. Cogliati; Abderrafi M. Ougouag

    2010-05-01

    Pebble bed reactors contain large numbers of spherical fuel elements arranged randomly. Determining the motion and location of these fuel elements is required for calculating certain parameters of pebble bed reactor operation. These simulations involve hundreds of thousands of pebbles and involve determining the entire core motion as pebbles are recirculated. Single processor algorithms for this are insufficient since they would take decades to centuries of wall-clock time. This paper describes the process of parallelizing and speeding up the PEBBLES pebble mechanics simulation code. Both shared memory programming with the Open Multi-Processing API and distributed memory programming with the Message Passing Interface API are used in simultaneously in this process. A new shared memory lock-less linear time collision detection algorithm is described. This method allows faster detection of pebbles in contact than generic methods. These combine to make full recirculations on AVR sized reactors possible in months of wall clock time.

  16. Rotary drive mechanism

    SciTech Connect (OSTI)

    Kenderdine, E.W.

    1991-10-08

    This patent describes a rotary drive mechanism which includes a rotary solenoid having a stator and multi-poled rotor. A moving member rotates with the rotor and is biased by a biasing device. The biasing device causes a further rotational movement after rotation by the rotary solenoid. Thus, energization of the rotary solenoid moves the member in one direction to one position and biases the biasing device against the member. Subsequently, de- energization of the rotary solenoid causes the biasing device to move the member in the same direction to another position from where the moving member is again movable by energization and de-energization of the rotary solenoid. Preferably, the moving member is a multi-lobed cam having the same number of lobes as the rotor has poles. An anti- overdrive device is also preferably provided for preventing overdrive in the forward direction or a reverse rotation of the moving member and for precisely aligning the moving member.

  17. Mechanically expandable annular seal

    DOE Patents [OSTI]

    Gilmore, R.F.

    1983-07-19

    A mechanically expandable annular reusable seal assembly to form an annular hermetic barrier between two stationary, parallel, and planar containment surfaces is described. A rotatable ring, attached to the first surface, has ring wedges resembling the saw-tooth array of a hole saw. Matching seal wedges are slidably attached to the ring wedges and have their motion restricted to be perpendicular to the second surface. Each seal wedge has a face parallel to the second surface. An annular elastomer seal has a central annular region attached to the seal wedges' parallel faces and has its inner and outer circumferences attached to the first surface. A rotation of the ring extends the elastomer seal's central region perpendicularly towards the second surface to create the fluid tight barrier. A counter rotation removes the barrier. 6 figs.

  18. Mechanically expandable annular seal

    DOE Patents [OSTI]

    Gilmore, Richard F. (Kennewick, WA)

    1983-01-01

    A mechanically expandable annular reusable seal assembly to form an annular hermetic barrier between two stationary, parallel, and planar containment surfaces. A rotatable ring, attached to the first surface, has ring wedges resembling the saw-tooth array of a hole saw. Matching seal wedges are slidably attached to the ring wedges and have their motion restricted to be perpendicular to the second surface. Each seal wedge has a face parallel to the second surface. An annular elastomer seal has a central annular region attached to the seal wedges' parallel faces and has its inner and outer circumferences attached to the first surface. A rotation of the ring extends the elastomer seal's central region perpendicularly towards the second surface to create the fluidtight barrier. A counterrotation removes the barrier.

  19. Rotary drive mechanism

    DOE Patents [OSTI]

    Kenderdine, Eugene W. (Albuquerque, NM)

    1991-01-01

    A rotary drive mechanism includes a rotary solenoid having a stator and multi-poled rotor. A moving member rotates with the rotor and is biased by a biasing device. The biasing device causes a further rotational movement after rotation by the rotary solenoid. Thus, energization of the rotary solenoid moves the member in one direction to one position and biases the biasing device against the member. Subsequently, de-energization of the rotary solenoid causes the biasing device to move the member in the same direction to another position from where the moving member is again movable by energization and de-energization of the rotary solenoid. Preferably, the moving member is a multi-lobed cam having the same number of lobes as the rotor has poles. An anti-overdrive device is also preferably provided for preventing overdrive in the forward direction or a reverse rotation of the moving member and for precisely aligning the moving member.

  20. Microfabricated therapeutic actuator mechanisms

    DOE Patents [OSTI]

    Northrup, M.A.; Ciarlo, D.R.; Lee, A.P.; Krulevitch, P.A.

    1997-07-08

    Electromechanical microstructures (microgrippers), either integrated circuit (IC) silicon-based or precision machined, to extend and improve the application of catheter-based interventional therapies for the repair of aneurysms in the brain or other interventional clinical therapies. These micromechanisms can be specifically applied to release platinum coils or other materials into bulging portions of the blood vessels also known as aneurysms. The ``micro`` size of the release mechanism is necessary since the brain vessels are the smallest in the body. Through a catheter more than one meter long, the micromechanism located at one end of the catheter can be manipulated from the other end thereof. The microgripper (micromechanism) of the invention will also find applications in non-medical areas where a remotely actuated microgripper or similar actuator would be useful or where micro-assembling is needed. 22 figs.

  1. Microfabricated therapeutic actuator mechanisms

    DOE Patents [OSTI]

    Northrup, Milton A.; Ciarlo, Dino R.; Lee, Abraham P.; Krulevitch, Peter A.

    1997-01-01

    Electromechanical microstructures (microgrippers), either integrated circuit (IC) silicon-based or precision machined, to extend and improve the application of catheter-based interventional therapies for the repair of aneurysms in the brain or other interventional clinical therapies. These micromechanisms can be specifically applied to release platinum coils or other materials into bulging portions of the blood vessels also known as aneurysms. The "micro" size of the release mechanism is necessary since the brain vessels are the smallest in the body. Through a catheter more than one meter long, the micromechanism located at one end of the catheter can be manipulated from the other end thereof. The microgripper (micromechanism) of the invention will also find applications in non-medical areas where a remotely actuated microgripper or similar actuator would be useful or where micro-assembling is needed.

  2. Diffusion-controlled reactions modeling in Geant4-DNA

    SciTech Connect (OSTI)

    Karamitros, M.; Luan, S.; Bernal, M.A.; Allison, J.; Baldacchino, G.; Davidkova, M.; Francis, Z.; Friedland, W.; Ivantchenko, V.; Ivantchenko, A.; Mantero, A.; Nieminem, P.; Santin, G.; Tran, H.N.; Stepan, V.; Incerti, S.

    2014-10-01

    Context Under irradiation, a biological system undergoes a cascade of chemical reactions that can lead to an alteration of its normal operation. There are different types of radiation and many competing reactions. As a result the kinetics of chemical species is extremely complex. The simulation becomes then a powerful tool which, by describing the basic principles of chemical reactions, can reveal the dynamics of the macroscopic system. To understand the dynamics of biological systems under radiation, since the 80s there have been on-going efforts carried out by several research groups to establish a mechanistic model that consists in describing all the physical, chemical and biological phenomena following the irradiation of single cells. This approach is generally divided into a succession of stages that follow each other in time: (1) the physical stage, where the ionizing particles interact directly with the biological material; (2) the physico-chemical stage, where the targeted molecules release their energy by dissociating, creating new chemical species; (3) the chemical stage, where the new chemical species interact with each other or with the biomolecules; (4) the biological stage, where the repairing mechanisms of the cell come into play. This article focuses on the modeling of the chemical stage. Method This article presents a general method of speeding-up chemical reaction simulations in fluids based on the Smoluchowski equation and Monte-Carlo methods, where all molecules are explicitly simulated and the solvent is treated as a continuum. The model describes diffusion-controlled reactions. This method has been implemented in Geant4-DNA. The keys to the new algorithm include: (1) the combination of a method to compute time steps dynamically with a Brownian bridge process to account for chemical reactions, which avoids costly fixed time step simulations; (2) a kd tree data structure for quickly locating, for a given molecule, its closest reactants. The performance advantage is presented in terms of complexity, and the accuracy of the new algorithm is demonstrated by simulating radiation chemistry in the context of the Geant4-DNA project. Application The time-dependent radiolytic yields of the main chemical species formed after irradiation are computed for incident protons at different energies (from 50 MeV to 500 keV). Both the time-evolution and energy dependency of the yields are discussed. The evolution, at one microsecond, of the yields of hydroxyls and solvated electrons with respect to the linear energy transfer is compared to theoretical and experimental data. According to our results, at high linear energy transfer, modeling radiation chemistry in the trading compartment representation might be adopted.

  3. Transportation Systems Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    TRACC RESEARCH Computational Fluid Dynamics Computational Structural Mechanics Transportation Systems Modeling TRANSPORTATION SYSTEMS MODELING Overview of TSM Transportation systems modeling research at TRACC uses the TRANSIMS (Transportation Analysis SIMulation System) traffic micro simulation code developed by the U.S. Department of Transportation (USDOT). The TRANSIMS code represents the latest generation of traffic simulation codes developed jointly under multiyear programs by USDOT, the

  4. Fundamental mechanisms of micromachine reliability

    SciTech Connect (OSTI)

    DE BOER,MAARTEN P.; SNIEGOWSKI,JEFFRY J.; KNAPP,JAMES A.; REDMOND,JAMES M.; MICHALSKE,TERRY A.; MAYER,THOMAS K.

    2000-01-01

    Due to extreme surface to volume ratios, adhesion and friction are critical properties for reliability of Microelectromechanical Systems (MEMS), but are not well understood. In this LDRD the authors established test structures, metrology and numerical modeling to conduct studies on adhesion and friction in MEMS. They then concentrated on measuring the effect of environment on MEMS adhesion. Polycrystalline silicon (polysilicon) is the primary material of interest in MEMS because of its integrated circuit process compatibility, low stress, high strength and conformal deposition nature. A plethora of useful micromachined device concepts have been demonstrated using Sandia National Laboratories' sophisticated in-house capabilities. One drawback to polysilicon is that in air the surface oxidizes, is high energy and is hydrophilic (i.e., it wets easily). This can lead to catastrophic failure because surface forces can cause MEMS parts that are brought into contact to adhere rather than perform their intended function. A fundamental concern is how environmental constituents such as water will affect adhesion energies in MEMS. The authors first demonstrated an accurate method to measure adhesion as reported in Chapter 1. In Chapter 2 through 5, they then studied the effect of water on adhesion depending on the surface condition (hydrophilic or hydrophobic). As described in Chapter 2, they find that adhesion energy of hydrophilic MEMS surfaces is high and increases exponentially with relative humidity (RH). Surface roughness is the controlling mechanism for this relationship. Adhesion can be reduced by several orders of magnitude by silane coupling agents applied via solution processing. They decrease the surface energy and render the surface hydrophobic (i.e. does not wet easily). However, only a molecular monolayer coats the surface. In Chapters 3-5 the authors map out the extent to which the monolayer reduces adhesion versus RH. They find that adhesion is independent of RH up to a threshold value, depending on the coating chemistry. The mechanism for the adhesion increase beyond this threshold value is that the coupling agent reconfigures from a surface to a bulk phase (Chapter 3). To investigate the details of how the adhesion increase occurs, the authors developed the mechanics for adhesion hysteresis measurements. These revealed that near-crack tip compression is the underlying cause of the adhesion increase (Chapter 4). A vacuum deposition chamber for silane coupling agent deposition was constructed. Results indicate that vapor deposited coatings are less susceptible to degradation at high RH (Chapter 5). To address issues relating to surfaces in relative motion, a new test structure to measure friction was developed. In contrast to other surface micromachined friction test structures, uniform apparent pressure is applied in the frictional contact zone (Chapter 6). The test structure will enable friction studies over a large pressure and dynamic range. In this LDRD project, the authors established an infrastructure for MEMS adhesion and friction metrology. They then characterized in detail the performance of hydrophilic and hydrophobic films under humid conditions, and determined mechanisms which limit this performance. These studies contribute to a fundamental understanding for MEMS reliability design rules. They also provide valuable data for MEMS packaging requirements.

  5. 2012Modeling_Factsheet.indd

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    simulation code (VERA) to model the formation of deposits on reactor fuel cladding and mechanical fretting within fuel assemblies to assess the potential for power uprates and...

  6. Micro electromechanical systems (MEMS) for mechanical engineers

    SciTech Connect (OSTI)

    Lee, A. P., LLNL

    1996-11-18

    The ongoing advances in Microelectromechanical Systems (MEMS) are providing man-kind the freedom to travel to dimensional spaces never before conceivable. Advances include new fabrication processes, new materials, tailored modeling tools, new fabrication machines, systems integration, and more detailed studies of physics and surface chemistry as applied to the micro scale. In the ten years since its inauguration, MEMS technology is penetrating industries of automobile, healthcare, biotechnology, sports/entertainment, measurement systems, data storage, photonics/optics, computer, aerospace, precision instruments/robotics, and environment monitoring. It is projected that by the turn of the century, MEMS will impact every individual in the industrial world, totaling sales up to $14 billion (source: System Planning Corp.). MEMS programs in major universities have spawned up all over the United States, preparing the brain-power and expertise for the next wave of MEMS breakthroughs. It should be pointed out that although MEMS has been initiated by electrical engineering researchers through the involvement of IC fabrication techniques, today it has evolved such that it requires a totally multi-disciplinary team to develop useful devices. Mechanical engineers are especially crucial to the success of MEMS development, since 90% of the physical realm involved is mechanical. Mechanical engineers are needed for the design of MEMS, the analysis of the mechanical system, the design of testing apparatus, the implementation of analytical tools, and the packaging process. Every single aspect of mechanical engineering is being utilized in the MEMS field today, however, the impact could be more substantial if more mechanical engineers are involved in the systems level designing. In this paper, an attempt is made to create the pathways for a mechanical engineer to enter in the MEMS field. Examples of application in optics and medical devices will be used to illustrate how mechanical engineers made impact. Through a basic understanding of the history of MEMS, the background physics and scaling in micromechanical systems, and an introduction to baseline MEMS processes, a mechanical engineer should be well on his way to Alice's wonderland in the ever-exciting playground of MEMS.

  7. Mechanical Behavior of Indium Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanical Behavior of Indium Nanostructures Print Indium is a key material in lead-free solder applications for microelectronics due to its excellent wetting properties, extended...

  8. INL '@work' heavy equipment mechanic

    SciTech Connect (OSTI)

    Christensen, Cad

    2008-01-01

    INL's Cad Christensen is a heavy equipment mechanic. For more information about INL careers, visit http://www.facebook.com/idahonationallaboratory.

  9. Mechanical Behavior of Indium Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    12.3.2 to investigate the small-scale mechanics of indium nanostructures. Scanning x-ray microdiffraction (SXRD) studies revealed that the indium microstructure is typical...

  10. Unique Auxin Regulation Mechanism Discovered

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Unique Auxin Regulation Mechanism Discovered Print The plant hormone auxin regulates many plant growth and development processes, including shoot growth, root branching, fruit...

  11. Unique Auxin Regulation Mechanism Discovered

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Auxin Regulation Mechanism Discovered Print Wednesday, 29 August 2007 00:00 The plant hormone auxin regulates many plant growth and development processes, including shoot growth,...

  12. INL '@work' heavy equipment mechanic

    ScienceCinema (OSTI)

    Christensen, Cad

    2013-05-28

    INL's Cad Christensen is a heavy equipment mechanic. For more information about INL careers, visit http://www.facebook.com/idahonationallaboratory.

  13. X-Ray Emitting GHz-Peaked Spectrum Galaxies: Testing a Dynamical-Radiative Model with Broad-Band Spectra

    SciTech Connect (OSTI)

    Ostorero, L.; Moderski, R.; Stawarz, L.; Diaferio, A.; Kowalska, I.; Cheung, C.C.; Kataoka, J.; Begelman, M.C.; Wagner, S.J.; ,

    2010-06-07

    In a dynamical-radiative model we recently developed to describe the physics of compact, GHz-Peaked-Spectrum (GPS) sources, the relativistic jets propagate across the inner, kpc-sized region of the host galaxy, while the electron population of the expanding lobes evolves and emits synchrotron and inverse-Compton (IC) radiation. Interstellar-medium gas clouds engulfed by the expanding lobes, and photoionized by the active nucleus, are responsible for the radio spectral turnover through free-free absorption (FFA) of the synchrotron photons. The model provides a description of the evolution of the GPS spectral energy distribution (SED) with the source expansion, predicting significant and complex high-energy emission, from the X-ray to the {gamma}-ray frequency domain. Here, we test this model with the broad-band SEDs of a sample of eleven X-ray emitting GPS galaxies with Compact-Symmetric-Object (CSO) morphology, and show that: (i) the shape of the radio continuum at frequencies lower than the spectral turnover is indeed well accounted for by the FFA mechanism; (ii) the observed X-ray spectra can be interpreted as non-thermal radiation produced via IC scattering of the local radiation fields off the lobe particles, providing a viable alternative to the thermal, accretion-disk dominated scenario. We also show that the relation between the hydrogen column densities derived from the X-ray (N{sub H}) and radio (N{sub HI}) data of the sources is suggestive of a positive correlation, which, if confirmed by future observations, would provide further support to our scenario of high-energy emitting lobes.

  14. MODEL AND ALGORITHM EVALUATION FOR THE HYBRID UF6 CONTAINER INSPECTION SYSTEM

    SciTech Connect (OSTI)

    McDonald, Benjamin S.; Jordan, David V.; Orton, Christopher R.; Mace, Emily K.; Smith, Leon E.; Wittman, Richard S.

    2011-06-14

    ABSTRACT Pacific Northwest National Laboratory (PNNL) is developing an automated UF6 cylinder verification station concept based on the combined collection of traditional enrichment-meter (186 keV photons from U-235) data and non-traditional, neutron-induced, high-energy gamma-signatures (3-8.5 MeV) with an array of collimated, medium-resolution scintillators. Previous (2010) work at PNNL demonstrated proof-of-principle that this hybrid method yields accurate, full-volume assay of the cylinder enrichment, reduces systematic errors when compared to several other enrichment assay methods, and provides simplified instrumentation and algorithms suitable for long-term unattended operations. We used Monte Carlo modeling with MCNP5 to support system design (e.g., number and configuration of detector arrays, and design of iron/poly collimators for enhanced (n,?) conversion) and enrichment algorithm development. We developed a first-generation modeling framework in 2010. These tools have since been expanded, refined and benchmarked against field measurements with a prototype system of a 30B cylinder population (0.2 to 4.95 weight % U-235). The MCNP5 model decomposes the radiation transport problem into a linear superposition of basis spectra representing contributions from the different uranium isotopes and gamma-ray generation mechanisms (e.g. neutron capture). This scheme accommodates fast generation of virtual assay signatures for arbitrary enrichment, material age, and fill variations. Ongoing (FY-2011) refinements to the physics model include accounting for generation of bremsstrahlung photons, arising primarily from the beta decay of Pa-234m, a U-238 daughter. We are using the refined model to optimize collimator design for the hybrid method. The traditional assay method benefits from a high degree of collimation (to isolate each detectors field-of-view) and relatively small detector area, while the non-traditional method benefits from a wide field-of-view, i.e. less collimation and larger detectors. We implement the enrichment-meter method by applying a square-wave digital filter to a raw spectrum and extracting the 186-keV peak area directly from the convolute spectrum. Ongoing enhancements to this approach include mitigating a systematic peak-area measurement deficit arising from curvature in the spectrum continuum shape. An optimized system prototype based on model results is utilized in a new set of 2011 field measurements, and model and measurement enrichment assay uncertainties are compared.

  15. Mechanical diode: Comparing numerical and experimental characterizations

    SciTech Connect (OSTI)

    Sagartz, M.J.; Segalman, D.; Simmermacher, T.

    1998-02-01

    In this introductory work, joint compliance is studied in both a numerical and experimental setting. A simple bolted interface is used as the test article and compliance is measured for the joint in both compression and in tension. This simple interface is shown to exhibit a strong non-linearity near the transition from compression to tension (or vice-versa). Modeling issues pertaining to numerically solving for the compliance are addressed. It is shown that the model predictions, in spite of convergence being very sensitive to numerical artifacts of the interface model, are in good agreement with experimentally measured strains and joint compliances. The joint behavior is a mechanical analogy to a diode, i.e., in compression, the joint is very stiff, acting almost as a rigid link, while in tension the joint is relatively soft, acting as a spring.

  16. Geochemical Reaction Mechanism Discovery from Molecular Simulation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Stack, Andrew G.; Kent, Paul R. C.

    2014-11-10

    Methods to explore reactions using computer simulation are becoming increasingly quantitative, versatile, and robust. In this review, a rationale for how molecular simulation can help build better geochemical kinetics models is first given. We summarize some common methods that geochemists use to simulate reaction mechanisms, specifically classical molecular dynamics and quantum chemical methods and discuss their strengths and weaknesses. Useful tools such as umbrella sampling and metadynamics that enable one to explore reactions are discussed. Several case studies wherein geochemists have used these tools to understand reaction mechanisms are presented, including water exchange and sorption on aqueous species and mineralmore » surfaces, surface charging, crystal growth and dissolution, and electron transfer. The impact that molecular simulation has had on our understanding of geochemical reactivity are highlighted in each case. In the future, it is anticipated that molecular simulation of geochemical reaction mechanisms will become more commonplace as a tool to validate and interpret experimental data, and provide a check on the plausibility of geochemical kinetic models.« less

  17. Fracture mechanics applied to the machining of brittle materials

    SciTech Connect (OSTI)

    Hiatt, G.D.; Strenkowski, J.S.

    1988-12-01

    Research has begun on incorporating fracture mechanics into a model of the orthogonal cutting of brittle materials. Residual stresses are calculated for the machined material by a combination of Eulerian and Lagrangian finite element models and then used in the calculation of stress intensity factors by the Green`s Function Method.

  18. NUMERICAL MODELING OF CATHODE CONTACT MATERIAL DENSIFICATION

    SciTech Connect (OSTI)

    Koeppel, Brian J.; Liu, Wenning N.; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2011-11-01

    Numerical modeling was used to simulate the constrained sintering process of the cathode contact layer during assembly of solid oxide fuel cells (SOFCs). A finite element model based on the continuum theory for sintering of porous bodies was developed and used to investigate candidate low-temperature cathode contact materials. Constitutive parameters for various contact materials under investigation were estimated from dilatometry screening tests, and the influence of processing time, processing temperature, initial grain size, and applied compressive stress on the free sintering response was predicted for selected candidate materials. The densification behavior and generated stresses within a 5-cell planar SOFC stack during sintering, high temperature operation, and room temperature shutdown were predicted. Insufficient constrained densification was observed in the stack at the proposed heat treatment, but beneficial effects of reduced grain size, compressive stack preload, and reduced thermal expansion coefficient on the contact layer densification and stresses were observed.

  19. QUANTUM MECHANICS WITHOUT STATISTICAL POSTULATES

    SciTech Connect (OSTI)

    G. GEIGER; ET AL

    2000-11-01

    The Bohmian formulation of quantum mechanics describes the measurement process in an intuitive way without a reduction postulate. Due to the chaotic motion of the hidden classical particle all statistical features of quantum mechanics during a sequence of repeated measurements can be derived in the framework of a deterministic single system theory.

  20. Mechanical Solutions Inc | Open Energy Information

    Open Energy Info (EERE)

    Mechanical Solutions Inc Jump to: navigation, search Name: Mechanical Solutions Inc Place: New York Product: New York-based contractor. References: Mechanical Solutions Inc1 This...

  1. Statistical mechanics based on fractional classical and quantum mechanics

    SciTech Connect (OSTI)

    Korichi, Z.; Meftah, M. T.

    2014-03-15

    The purpose of this work is to study some problems in statistical mechanics based on the fractional classical and quantum mechanics. At first stage we have presented the thermodynamical properties of the classical ideal gas and the system of N classical oscillators. In both cases, the Hamiltonian contains fractional exponents of the phase space (position and momentum). At the second stage, in the context of the fractional quantum mechanics, we have calculated the thermodynamical properties for the black body radiation, studied the Bose-Einstein statistics with the related problem of the condensation and the Fermi-Dirac statistics.

  2. Theoretical Study of the Inverting Mechanism in a Processive Cellobiohydrolase with Quantum Mechanical Calculations

    SciTech Connect (OSTI)

    Kim, S.; Payne, C. M.; Himmel, M. E.; Crowley, M. F.; Paton, R. S.; Beckham, G. T.

    2012-01-01

    The Hypocrea jecorina Family 6 cellobiohydrolase (Cel6A) is one of most efficient enzymes for cellulose deconstruction to soluble sugars and is thus of significant current interest for the growing biofuels industry. Cel6A is known to hydrolyze b(1,4)-glycosidic linkages in cellulose via an inverting mechanism, but there are still questions that remain regarding the role of water and the catalytic base. Here we study the inverting, single displacement, hydrolytic reaction mechanism in Cel6A using density functional theory (DFT) calculations. The computational model used to follow the reaction is a truncated active site model with several explicit waters based on structural studies of H. jecorina Cel6A. Proposed mechanisms are evaluated with several density functionals. From our calculations, the role of the water in nucleophilic attack on the anomeric carbon, and the roles of several residues in the active site loops are elucidated explicitly for the first time. We also apply quantum mechanical calculations to understand the proton transfer reaction which completes the catalytic cycle.

  3. Phase space quantum mechanics - Direct

    SciTech Connect (OSTI)

    Nasiri, S.; Sobouti, Y.; Taati, F.

    2006-09-15

    Conventional approach to quantum mechanics in phase space (q,p), is to take the operator based quantum mechanics of Schroedinger, or an equivalent, and assign a c-number function in phase space to it. We propose to begin with a higher level of abstraction, in which the independence and the symmetric role of q and p is maintained throughout, and at once arrive at phase space state functions. Upon reduction to the q- or p-space the proposed formalism gives the conventional quantum mechanics, however, with a definite rule for ordering of factors of noncommuting observables. Further conceptual and practical merits of the formalism are demonstrated throughout the text.

  4. Mechanical Characterization of Rigid Polyurethane Foams.

    SciTech Connect (OSTI)

    Lu, Wei-Yang

    2014-12-01

    Foam materials are used to protect sensitive components from impact loading. In order to predict and simulate the foam performance under various loading conditions, a validated foam model is needed and the mechanical properties of foams need to be characterized. Uniaxial compression and tension tests were conducted for different densities of foams under various temperatures and loading rates. Crush stress, tensile strength, and elastic modulus were obtained. A newly developed confined compression experiment provided data for investigating the foam flow direction. A biaxial tension experiment was also developed to explore the damage surface of a rigid polyurethane foam.

  5. Durability Improvements Through Degradation Mechanism Studies...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Degradation Mechanism Studies Durability Improvements Through Degradation Mechanism Studies Presented at the Department of Energy Fuel Cell Projects Kickoff Meeting,...

  6. Sandia Energy - Statistical Mechanics with Density Functional...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Statistical Mechanics with Density Functional Theory Accuracy Home Highlights - HPC Statistical Mechanics with Density Functional Theory Accuracy Previous Next Statistical...

  7. Mechanically balanced tapered plug valve

    DOE Patents [OSTI]

    Anaya, Jose R. (Coacalco, MX)

    1985-01-01

    The invention is a novel hermetic tapered plug valve having a spring-like resilient mechanism for providing axial balance to the plug and thereby prevent valve lock up.

  8. Mechanical Behavior of Indium Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Publication about this research: G. Lee, J.Y. Kim, A.S. Budiman, N. Tamura, M. Kunz, K. Chen, M.J. Burek, J.R. Greer, and T.Y. Tsui, "Fabrication, structure and mechanical...

  9. Unique Auxin Regulation Mechanism Discovered

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Unique Auxin Regulation Mechanism Discovered Unique Auxin Regulation Mechanism Discovered Print Wednesday, 29 August 2007 00:00 The plant hormone auxin regulates many plant growth and development processes, including shoot growth, root branching, fruit ripening, tropisms, and flowering. But how such a simple molecule elicits such a variety of cellular responses has been a mystery. An important breakthrough came in 2005, wh en a conserved plant protein known as TIR1 (part of a protein destruction

  10. Mechanical Behavior of Indium Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanical Behavior of Indium Nanostructures Print Indium is a key material in lead-free solder applications for microelectronics due to its excellent wetting properties, extended ductility, and high electrical conductivity. With the size of electronic devices continuing to shrink and the promise of indium-based nanotechnologies, it is important to develop a fundamental understanding of this material's small-scale mechanical properties and reliability. Researchers from the University of

  11. Mechanical Behavior of Indium Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanical Behavior of Indium Nanostructures Print Indium is a key material in lead-free solder applications for microelectronics due to its excellent wetting properties, extended ductility, and high electrical conductivity. With the size of electronic devices continuing to shrink and the promise of indium-based nanotechnologies, it is important to develop a fundamental understanding of this material's small-scale mechanical properties and reliability. Researchers from the University of

  12. Mechanical Behavior of Indium Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanical Behavior of Indium Nanostructures Print Indium is a key material in lead-free solder applications for microelectronics due to its excellent wetting properties, extended ductility, and high electrical conductivity. With the size of electronic devices continuing to shrink and the promise of indium-based nanotechnologies, it is important to develop a fundamental understanding of this material's small-scale mechanical properties and reliability. Researchers from the University of

  13. Mechanical Behavior of Indium Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanical Behavior of Indium Nanostructures Print Indium is a key material in lead-free solder applications for microelectronics due to its excellent wetting properties, extended ductility, and high electrical conductivity. With the size of electronic devices continuing to shrink and the promise of indium-based nanotechnologies, it is important to develop a fundamental understanding of this material's small-scale mechanical properties and reliability. Researchers from the University of

  14. Mechanical Behavior of Indium Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanical Behavior of Indium Nanostructures Print Indium is a key material in lead-free solder applications for microelectronics due to its excellent wetting properties, extended ductility, and high electrical conductivity. With the size of electronic devices continuing to shrink and the promise of indium-based nanotechnologies, it is important to develop a fundamental understanding of this material's small-scale mechanical properties and reliability. Researchers from the University of

  15. Mechanical Behavior of Indium Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanical Behavior of Indium Nanostructures Print Indium is a key material in lead-free solder applications for microelectronics due to its excellent wetting properties, extended ductility, and high electrical conductivity. With the size of electronic devices continuing to shrink and the promise of indium-based nanotechnologies, it is important to develop a fundamental understanding of this material's small-scale mechanical properties and reliability. Researchers from the University of

  16. Mechanical Behavior of Indium Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanical Behavior of Indium Nanostructures Print Indium is a key material in lead-free solder applications for microelectronics due to its excellent wetting properties, extended ductility, and high electrical conductivity. With the size of electronic devices continuing to shrink and the promise of indium-based nanotechnologies, it is important to develop a fundamental understanding of this material's small-scale mechanical properties and reliability. Researchers from the University of

  17. Mechanical Behavior of Indium Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanical Behavior of Indium Nanostructures Mechanical Behavior of Indium Nanostructures Print Wednesday, 26 May 2010 00:00 Indium is a key material in lead-free solder applications for microelectronics due to its excellent wetting properties, extended ductility, and high electrical conductivity. With the size of electronic devices continuing to shrink and the promise of indium-based nanotechnologies, it is important to develop a fundamental understanding of this material's small-scale

  18. Mechanical Response of Thermoelectric Materials

    SciTech Connect (OSTI)

    Wereszczak, Andrew A.; Case, Eldon D.

    2015-05-01

    A sufficient mechanical response of thermoelectric materials (TEMats) to structural loadings is a prerequisite to the exploitation of any candidate TEMat's thermoelectric efficiency. If a TEMat is mechanically damaged or cracks from service-induced stresses, then its thermal and electrical functions can be compromised or even cease. Semiconductor TEMats tend to be quite brittle and have a high coefficient of thermal expansion; therefore, they can be quite susceptible to mechanical failure when subjected to operational thermal gradients. Because of this, sufficient mechanical response (vis-a-vis, mechanical properties) of any candidate TEMat must be achieved and sustained in the context of the service-induced stress state to which it is subjected. This report provides an overview of the mechanical responses of state-of-the-art TEMats; discusses the relevant properties that are associated with those responses and their measurement; and describes important, nonequilibrium phenomena that further complicate their use in thermoelectric devices. For reference purposes, the report also includes several appendixes that list published data on elastic properties and strengths of a variety of TEMats.

  19. COLLOQUIUM: Quantum Mechanics and Spacetime Geometry | Princeton Plasma

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Physics Lab February 25, 2014, 4:00pm to 5:30pm Colloquia MBG Auditorium COLLOQUIUM: Quantum Mechanics and Spacetime Geometry Professor Juan Maldacena Institute for Advanced Study Quantum mechanics is important for determining the geometry of spacetime. We will review the role of quantum fluctuations that determine the large scale structure of the universe. In some model universes we can give an alternative description of the physics in terms of a theory of particles that lives on its

  20. Deactivation mechanisms of NOx storage materials arising from thermal aging

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    and sulfur poisoning | Department of Energy mechanisms of NOx storage materials arising from thermal aging and sulfur poisoning Deactivation mechanisms of NOx storage materials arising from thermal aging and sulfur poisoning Presents the reliationship between Pt particle size and NOx storage performance over model catalysts. Novel reaction protocol designed to decouple effects of thermal deactivation and incomplete desulfation. PDF icon deer08_muntean.pdf More Documents & Publications

  1. Benchmark Reaction Mechanisms and Kinetics for Lean NOx Traps | Department

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    of Energy Benchmark Reaction Mechanisms and Kinetics for Lean NOx Traps Benchmark Reaction Mechanisms and Kinetics for Lean NOx Traps 2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon acep_01_larson.pdf More Documents & Publications Development of Chemical Kinetic Models for Lean NOx Traps Development of Optimal Catalyst Designs and Operating Strategies for Lean NOx Reduction in Coupled

  2. Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Kinetics and Ion Mobility in Electrode Materials for Advanced Lithium Ion Batteries Materials Characterization Capabilities at the High Temperature Materials Laboratory and...

  3. Mechanism and Kinetic Modeling of Hydrogenation in The Organic...

    Office of Scientific and Technical Information (OSTI)

    DE-AC52-07NA27344 Resource Type: Journal Article Resource Relation: Journal Name: Journal of Physical Chemistry A, vol. 119, na, March 15, 2015, pp. 943-951 Research Org:...

  4. Mechanism and Kinetic Modeling of Hydrogenation in The Organic...

    Office of Scientific and Technical Information (OSTI)

    Number(s): LLNL-JRNL-662218 DOE Contract Number: DE-AC52-07NA27344 Resource Type: Journal Article Resource Relation: Journal Name: Journal of Physical Chemistry A, vol. 119,...

  5. Coarse-grained Energy Modeling of Rollback/Recovery Mechanisms...

    Office of Scientific and Technical Information (OSTI)

    Resource Type: Conference Resource Relation: Conference: Fault Tolerance for HPC at eXtreme Scale (FTXS) Workshop held June 23-24, 2014 in Atlanta, GA.; Related...

  6. A Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal...

    Open Energy Info (EERE)

    on the fluid flow distribution in an HDR geothermal reservoir. Authors T. W. Hicks, R. J. Pine, J. Willis-Richards, S. Xu, A. J. Jupe and N. E. V. Rodrigues Published Journal...

  7. STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS...

    Office of Scientific and Technical Information (OSTI)

    These aspects of crystal deformation are manifestations of the evolution of the underlying ... When used to predict the evolution of the dislocation system, the planar motion of ...

  8. Frictional granular mechanics: A variational approach

    SciTech Connect (OSTI)

    Holtzman, R.; Silin, D.B.; Patzek, T.W.

    2009-10-16

    The mechanical properties of a cohesionless granular material are evaluated from grain-scale simulations. Intergranular interactions, including friction and sliding, are modeled by a set of contact rules based on the theories of Hertz, Mindlin, and Deresiewicz. A computer generated, three-dimensional, irregular pack of spherical grains is loaded by incremental displacement of its boundaries. Deformation is described by a sequence of static equilibrium configurations of the pack. A variational approach is employed to find the equilibrium configurations by minimizing the total work against the intergranular loads. Effective elastic moduli are evaluated from the intergranular forces and the deformation of the pack. Good agreement between the computed and measured moduli, achieved with no adjustment of material parameters, establishes the physical soundness of the proposed model.

  9. Study of. lambda. parameters and crossover phenomena in SU(N) x SU(N) sigma models in two dimensions

    SciTech Connect (OSTI)

    Shigemitsu, J; Kogut, J B

    1981-01-01

    The spin system analogues of recent studies of the string tension and ..lambda.. parameters of SU(N) gauge theories in 4 dimensions are carried out for the SU(N) x SU(N) and O(N) models in 2 dimensions. The relations between the ..lambda.. parameters of both the Euclidean and Hamiltonian formulation of the lattice models and the ..lambda.. parameter of the continuum models are obtained. The one loop finite renormalization of the speed of light in the lattice Hamiltonian formulations of the O(N) and SU(N) x SU(N) models is calculated. Strong coupling calculations of the mass gaps of these spin models are done for all N and the constants of proportionality between the gap and the ..lambda.. parameter of the continuum models are obtained. These results are contrasted with similar calculations for the SU(N) gauge models in 3+1 dimensions. Identifying suitable coupling constants for discussing the N ..-->.. infinity limits, the numerical results suggest that the crossover from weak to strong coupling in the lattice O(N) models becomes less abrupt as N increases while the crossover for the SU(N) x SU(N) models becomes more abrupt. The crossover in SU(N) gauge theories also becomes more abrupt with increasing N, however, at an even greater rate than in the SU(N) x SU(N) spin models.

  10. UZ Colloid Transport Model

    SciTech Connect (OSTI)

    M. McGraw

    2000-04-13

    The UZ Colloid Transport model development plan states that the objective of this Analysis/Model Report (AMR) is to document the development of a model for simulating unsaturated colloid transport. This objective includes the following: (1) use of a process level model to evaluate the potential mechanisms for colloid transport at Yucca Mountain; (2) Provide ranges of parameters for significant colloid transport processes to Performance Assessment (PA) for the unsaturated zone (UZ); (3) Provide a basis for development of an abstracted model for use in PA calculations.

  11. Renormalization group flow and fixed point of the lattice topological charge in the 2D O(3) {sigma} model

    SciTech Connect (OSTI)

    DElia, M.; Farchioni, F.; Papa, A.

    1997-02-01

    We study the renormalization group evolution up to the fixed point of the lattice topological susceptibility in the 2D O(3) nonlinear {sigma} model. We start with a discretization of the continuum topological charge by a local charge density polynomial in the lattice fields. Among the different choices we propose also a Symanzik-improved lattice topological charge. We check step by step in the renormalization group iteration the progressive dumping of quantum fluctuations, which are responsible for the additive and multiplicative renormalizations of the lattice topological susceptibility with respect to the continuum definition. We find that already after three iterations these renormalizations are negligible and an excellent approximation of the fixed point is achieved. We also check by an explicit calculation that the assumption of slowly varying fields in iterating the renormalization group does not lead to a good approximation of the fixed point charge operator. {copyright} {ital 1997} {ital The American Physical Society}

  12. Majorana Electroformed Copper Mechanical Analysis

    SciTech Connect (OSTI)

    Overman, Nicole R.; Overman, Cory T.; Kafentzis, Tyler A.; Edwards, Danny J.; Hoppe, Eric W.

    2012-04-30

    The MAJORANA DEMONSTRATOR is a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay. The DEMONSTRATOR will utilize ultra high purity electroformed copper for a variety of detector components and shielding. A preliminary mechanical evaluation was performed on the Majorana prototype electroformed copper material. Several samples were removed from a variety of positions on the mandrel. Tensile testing, optical metallography, scanning electron microscopy, and hardness testing were conducted to evaluate mechanical response. Analyses carried out on the Majorana prototype copper to this point show consistent mechanical response from a variety of test locations. Evaluation shows the copper meets or exceeds the design specifications.

  13. Recent Developments in No-Core Shell-Model Calculations

    SciTech Connect (OSTI)

    Navratil, P; Quaglioni, S; Stetcu, I; Barrett, B R

    2009-03-20

    We present an overview of recent results and developments of the no-core shell model (NCSM), an ab initio approach to the nuclear many-body problem for light nuclei. In this aproach, we start from realistic two-nucleon or two- plus three-nucleon interactions. Many-body calculations are performed using a finite harmonic-oscillator (HO) basis. To facilitate convergence for realistic inter-nucleon interactions that generate strong short-range correlations, we derive effective interactions by unitary transformations that are tailored to the HO basis truncation. For soft realistic interactions this might not be necessary. If that is the case, the NCSM calculations are variational. In either case, the ab initio NCSM preserves translational invariance of the nuclear many-body problem. In this review, we, in particular, highlight results obtained with the chiral two- plus three-nucleon interactions. We discuss efforts to extend the applicability of the NCSM to heavier nuclei and larger model spaces using importance-truncation schemes and/or use of effective interactions with a core. We outline an extension of the ab initio NCSM to the description of nuclear reactions by the resonating group method technique. A future direction of the approach, the ab initio NCSM with continuum, which will provide a complete description of nuclei as open systems with coupling of bound and continuum states is given in the concluding part of the review.

  14. Battery Vent Mechanism And Method

    DOE Patents [OSTI]

    Ching, Larry K. W. (Littleton, CO)

    2000-02-15

    Disclosed herein is a venting mechanism for a battery. The venting mechanism includes a battery vent structure which is located on the battery cover and may be integrally formed therewith. The venting mechanism includes an opening extending through the battery cover such that the opening communicates with a plurality of battery cells located within the battery case. The venting mechanism also includes a vent manifold which attaches to the battery vent structure. The vent manifold includes a first opening which communicates with the battery vent structure opening and second and third openings which allow the vent manifold to be connected to two separate conduits. In this manner, a plurality of batteries may be interconnected for venting purposes, thus eliminating the need to provide separate vent lines for each battery. The vent manifold may be attached to the battery vent structure by a spin-welding technique. To facilitate this technique, the vent manifold may be provided with a flange portion which fits into a corresponding groove portion on the battery vent structure. The vent manifold includes an internal chamber which is large enough to completely house a conventional battery flame arrester and overpressure safety valve. In this manner, the vent manifold, when installed, lessens the likelihood of tampering with the flame arrester and safety valve.

  15. Mechanical scriber for semiconductor devices

    DOE Patents [OSTI]

    Lin, Peter T. (East Brunswick, NJ)

    1985-01-01

    A mechanical scriber using a scribing tip, such as a diamond, provides controlled scriber forces with a spring-loaded compound lever arrangement. The scribing force and range of scribing depth are adjusted by a pair of adjustable micrometer heads. A semiconductor device, such as a multilayer solar cell, can be formed into scribed strips at each layer.

  16. Mechanical scriber for semiconductor devices

    DOE Patents [OSTI]

    Lin, P.T.

    1985-03-05

    A mechanical scriber using a scribing tip, such as a diamond, provides controlled scriber forces with a spring-loaded compound lever arrangement. The scribing force and range of scribing depth are adjusted by a pair of adjustable micrometer heads. A semiconductor device, such as a multilayer solar cell, can be formed into scribed strips at each layer. 5 figs.

  17. Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Modeling | Department of Energy 10 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. PDF icon es082_sastry_2010_p.pdf More Documents & Publications track 3: enhanced geothermal systems (EGS) | geothermal 2015 peer review Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined Electrodes 2015 GTO Peer Review | Poster Session

  18. Career Map: Mechanical Engineer | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Mechanical Engineer Career Map: Mechanical Engineer A mechanical engineer works with a large yellow robotic arm. Mechanical Engineer Position Title Mechanical Engineer Alternate Title(s) Project Engineer, Quality Engineer, Research Engineer, Design Engineer, Sales Engineer Education & Training Level Advanced, Bachelor's degree required, prefer graduate degree Education & Training Level Description Mechanical engineers need a bachelor's degree. A graduate degree is typically needed for

  19. Method of predicting mechanical properties of decayed wood

    DOE Patents [OSTI]

    Kelley, Stephen S.

    2003-07-15

    A method for determining the mechanical properties of decayed wood that has been exposed to wood decay microorganisms, comprising: a) illuminating a surface of decayed wood that has been exposed to wood decay microorganisms with wavelengths from visible and near infrared (VIS-NIR) spectra; b) analyzing the surface of the decayed wood using a spectrometric method, the method generating a first spectral data of wavelengths in VIS-NIR spectra region; and c) using a multivariate analysis to predict mechanical properties of decayed wood by comparing the first spectral data with a calibration model, the calibration model comprising a second spectrometric method of spectral data of wavelengths in VIS-NIR spectra obtained from a reference decay wood, the second spectral data being correlated with a known mechanical property analytical result obtained from the reference decayed wood.

  20. NREL: Technology Transfer - Popular Mechanics: Scientists Break...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Popular Mechanics: Scientists Break This Virtual Power Grid to Save the Real One July 27, 2015 Popular Mechanics describes how NREL's Energy Systems Integration Facility (ESIF)...

  1. Shaoxing Jinggong Mechanical and Electrical Research Institute...

    Open Energy Info (EERE)

    Shaoxing Jinggong Mechanical and Electrical Research Institute Company SJMERI Jump to: navigation, search Name: Shaoxing Jinggong Mechanical and Electrical Research Institute...

  2. Multiple Mechanisms of Uranium Immobilization by Cellulomonas...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Multiple Mechanisms of Uranium Immobilization by Cellulomonas sp. Strain ES6 Citation Details In-Document Search Title: Multiple Mechanisms of Uranium ...

  3. Excitation Energy Sorting Mechanisms in Fission (Conference)...

    Office of Scientific and Technical Information (OSTI)

    Excitation Energy Sorting Mechanisms in Fission Citation Details In-Document Search Title: Excitation Energy Sorting Mechanisms in Fission You are accessing a document from the...

  4. CONTROL OF MECHANICALLY ACTIVATED POLYMERSOME FUSION: FACTORS...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Journal Article: CONTROL OF MECHANICALLY ACTIVATED POLYMERSOME FUSION: FACTORS AFFECTING FUSION. Citation Details In-Document Search Title: CONTROL OF MECHANICALLY ACTIVATED...

  5. Mechanism and Substrate Recognition of 2-Hydroxyethylphosphonate...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Journal Article: Mechanism and Substrate Recognition of 2-Hydroxyethylphosphonate Dioxygenase Citation Details In-Document Search Title: Mechanism ...

  6. Near-field NanoThermoMechanical memory

    SciTech Connect (OSTI)

    Elzouka, Mahmoud; Ndao, Sidy

    2014-12-15

    In this letter, we introduce the concept of NanoThermoMechanical Memory. Unlike electronic memory, a NanoThermoMechanical memory device uses heat instead of electricity to record, store, and recover data. Memory function is achieved through the coupling of near-field thermal radiation and thermal expansion resulting in negative differential thermal resistance and thermal latching. Here, we demonstrate theoretically via numerical modeling the concept of near-field thermal radiation enabled negative differential thermal resistance that achieves bistable states. Design and implementation of a practical silicon based NanoThermoMechanical memory device are proposed along with a study of its dynamic response under write/read cycles. With more than 50% of the world's energy losses being in the form of heat along with the ever increasing need to develop computer technologies which can operate in harsh environments (e.g., very high temperatures), NanoThermoMechanical memory and logic devices may hold the answer.

  7. Carbonation Mechanism of Reservoir Rock by Supercritical Carbon Dioxide

    Broader source: Energy.gov [DOE]

    Project Objectives: Elucidate comprehensively the carbonation reaction mechanisms between supercritical carbon dioxide (scCO2) and reservoir rocks consisting of different mineralogical compositions in aqueous and non-aqueous environments at temperatures of up to 250ºC, and to develop chemical modeling of CO2-reservior rock interactions.

  8. Chemically assisted mechanical refrigeration process

    DOE Patents [OSTI]

    Vobach, A.R.

    1987-06-23

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator. 5 figs.

  9. Chemically assisted mechanical refrigeration process

    DOE Patents [OSTI]

    Vobach, Arnold R.

    1987-01-01

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

  10. Chemically assisted mechanical refrigeration process

    DOE Patents [OSTI]

    Vobach, Arnold R.

    1987-01-01

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing he evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

  11. Chemically assisted mechanical refrigeration process

    DOE Patents [OSTI]

    Vobach, A.R.

    1987-11-24

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator. 5 figs.

  12. Locking mechanism for indexing device

    DOE Patents [OSTI]

    Lindemeyer, Carl W. (Aurora, IL)

    1984-01-01

    Disclosed is a locking mechanism for an indexing spindle. A conventional r gear having outwardly extending teeth is affixed to the spindle. Also included is a rotatably mounted camshaft whose axis is arranged in skewed relationship with the axis of the spindle. A disk-like wedge having opposing camming surfaces is eccentrically mounted on the camshaft. As the camshaft is rotated, the camming surfaces of the disc-like member are interposed between adjacent gear teeth with a wiping action that wedges the disc-like member between the gear teeth. A zero backlash engagement between disc-like member and gear results, with the engagement having a high mechanical advantage so as to effectively lock the spindle against bidirectional rotation.

  13. Mechanical Engineering Department Technical Review

    SciTech Connect (OSTI)

    Carr, R.B.; Denney, R.M.

    1981-07-01

    The Mechanical Engineering Department Technical Review is published to inform readers of various technical activities within the Department, promote exchange of ideas, and give credit to personnel who are achieving the results. The report is presented in two parts: technical achievements and publication abstracts. The first is divided into seven sections, each of which reports on an engineering division and its specific activities related to nuclear tests, nuclear explosives, weapons, energy systems, engineering sciences, magnetic fusion, and materials fabrication.

  14. Unique Auxin Regulation Mechanism Discovered

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Unique Auxin Regulation Mechanism Discovered Print The plant hormone auxin regulates many plant growth and development processes, including shoot growth, root branching, fruit ripening, tropisms, and flowering. But how such a simple molecule elicits such a variety of cellular responses has been a mystery. An important breakthrough came in 2005, wh en a conserved plant protein known as TIR1 (part of a protein destruction machinery system) was identified as a receptor for auxin. Now, an

  15. Particle Suspension Mechanisms - Supplemental Material

    SciTech Connect (OSTI)

    Dillon, M B

    2011-03-03

    This supplemental material provides a brief introduction to particle suspension mechanisms that cause exfoliated skin cells to become and remain airborne. The material presented here provides additional context to the primary manuscript and serves as background for designing possible future studies to assess the impact of skin cells as a source of infectious aerosols. This introduction is not intended to be comprehensive and interested readers are encouraged to consult the references cited.

  16. Mechanical Engineering Department technical abstracts

    SciTech Connect (OSTI)

    Denney, R.M.

    1982-07-01

    The Mechanical Engineering Department publishes listings of technical abstracts twice a year to inform readers of the broad range of technical activities in the Department, and to promote an exchange of ideas. Details of the work covered by an abstract may be obtained by contacting the author(s). Overall information about current activities of each of the Department's seven divisions precedes the technical abstracts.

  17. Unique Auxin Regulation Mechanism Discovered

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Unique Auxin Regulation Mechanism Discovered Print The plant hormone auxin regulates many plant growth and development processes, including shoot growth, root branching, fruit ripening, tropisms, and flowering. But how such a simple molecule elicits such a variety of cellular responses has been a mystery. An important breakthrough came in 2005, wh en a conserved plant protein known as TIR1 (part of a protein destruction machinery system) was identified as a receptor for auxin. Now, an

  18. Unique Auxin Regulation Mechanism Discovered

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Unique Auxin Regulation Mechanism Discovered Print The plant hormone auxin regulates many plant growth and development processes, including shoot growth, root branching, fruit ripening, tropisms, and flowering. But how such a simple molecule elicits such a variety of cellular responses has been a mystery. An important breakthrough came in 2005, wh en a conserved plant protein known as TIR1 (part of a protein destruction machinery system) was identified as a receptor for auxin. Now, an

  19. Unique Auxin Regulation Mechanism Discovered

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Unique Auxin Regulation Mechanism Discovered Print The plant hormone auxin regulates many plant growth and development processes, including shoot growth, root branching, fruit ripening, tropisms, and flowering. But how such a simple molecule elicits such a variety of cellular responses has been a mystery. An important breakthrough came in 2005, wh en a conserved plant protein known as TIR1 (part of a protein destruction machinery system) was identified as a receptor for auxin. Now, an

  20. GUI for Structural Mechanics Codes

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Development of GUI for Structural Mechanics Codes The TRACC Cluster gives its users a lot of flexibility when it comes to requesting software version of LS-DYNA and computational resources for submitted jobs. To fully utilize that flexibility, users need to get familiar with on-line documentation of all the installed releases of different software and modules on the cluster. As on other LINUX based HPC systems, the submission and controlling of LS-DYNA is done through text commands. Especially

  1. Mechanical engineering department technical review

    SciTech Connect (OSTI)

    Carr, R.B. Denney, R.M.

    1981-01-01

    The Mechanical Engineering Department Technical Review is published to: (1) inform the readers of various technical activities within the department, (2) promote exchange of ideas, and (3) give credit to the personnel who are achieving the results. The report is formatted into two parts: technical acievements and publication abstracts. The first is divided into eight sections, one for each division in the department providing the reader with the names of the personnel and the division accomplishing the work.

  2. The Vainshtein mechanism in the cosmic web

    SciTech Connect (OSTI)

    Falck, Bridget; Koyama, Kazuya; Zhao, Gong-bo; Li, Baojiu E-mail: kazuya.koyama@port.ac.uk E-mail: baojiu.li@durham.ac.uk

    2014-07-01

    We investigate the dependence of the Vainshtein screening mechanism on the cosmic web morphology of both dark matter particles and halos as determined by ORIGAMI. Unlike chameleon and symmetron screening, which come into effect in regions of high density, Vainshtein screening instead depends on the dimensionality of the system, and screened bodies can still feel external fields. ORIGAMI is well-suited to this problem because it defines morphologies according to the dimensionality of the collapsing structure and does not depend on a smoothing scale or density threshold parameter. We find that halo particles are screened while filament, wall, and void particles are unscreened, and this is independent of the particle density. However, after separating halos according to their large scale cosmic web environment, we find no difference in the screening properties of halos in filaments versus halos in clusters. We find that the fifth force enhancement of dark matter particles in halos is greatest well outside the virial radius. We confirm the theoretical expectation that even if the internal field is suppressed by the Vainshtein mechanism, the object still feels the fifth force generated by the external fields, by measuring peculiar velocities and velocity dispersions of halos. Finally, we investigate the morphology and gravity model dependence of halo spins, concentrations, and shapes.

  3. CENTIMETER CONTINUUM OBSERVATIONS OF THE NORTHERN HEAD OF THE HH 80/81/80N JET: REVISING THE ACTUAL DIMENSIONS OF A PARSEC-SCALE JET

    SciTech Connect (OSTI)

    Masque, Josep M.; Estalella, Robert; Girart, Josep M.; Rodriguez, Luis F.; Beltran, Maria T.

    2012-10-10

    We present 6 and 20 cm Jansky Very Large Array/Very Large Array observations of the northern head of the HH 80/81/80N jet, one of the largest collimated jet systems known so far, aimed to look for knots farther than HH 80N, the northern head of the jet. Aligned with the jet and 10' northeast of HH 80N, we found a radio source not reported before, with a negative spectral index similar to that of HH 80, HH 81, and HH 80N. The fit of a precessing jet model to the knots of the HH 80/81/80N jet, including the new source, shows that the position of this source is close to the jet path resulting from the modeling. If the new source belongs to the HH 80/81/80N jet, its derived size and dynamical age are 18.4 pc and >9 Multiplication-Sign 10{sup 3} yr, respectively. If the jet is symmetric, its southern lobe would expand beyond the cloud edge resulting in an asymmetric appearance of the jet. Based on the updated dynamical age, we speculate on the possibility that the HH 80/81/80N jet triggered the star formation observed in a dense core found ahead of HH 80N, which shows signposts of interaction with the jet. These results indicate that parsec-scale radio jets can play a role in the stability of dense clumps and the regulation of star formation in the molecular cloud.

  4. The spectral variability of the GHZ-Peaked spectrum radio source PKS 1718-649 and a comparison of absorption models

    SciTech Connect (OSTI)

    Tingay, S. J.; Macquart, J.-P.; Wayth, R. B.; Trott, C. M.; Emrich, D.; Collier, J. D.; Wong, G. F.; Rees, G.; Stevens, J.; Carretti, E.; Callingham, J. R.; Gaensler, B. M.; McKinley, B.; Briggs, F.; Bernardi, G.; Bowman, J. D.; Cappallo, R. J.; Corey, B. E.; Deshpande, A. A.; Goeke, R.; and others

    2015-02-01

    Using the new wideband capabilities of the ATCA, we obtain spectra for PKS 1718-649, a well-known gigahertz-peaked spectrum radio source. The observations, between approximately 1 and 10 GHz over 3 epochs spanning approximately 21 months, reveal variability both above the spectral peak at ∼3 GHz and below the peak. The combination of the low- and high-frequency variability cannot be easily explained using a single absorption mechanism, such as free–free absorption or synchrotron self-absorption. We find that the PKS 1718-649 spectrum and its variability are best explained by variations in the free–free optical depth on our line of sight to the radio source at low frequencies (below the spectral peak) and the adiabatic expansion of the radio source itself at high frequencies (above the spectral peak). The optical depth variations are found to be plausible when X-ray continuum absorption variability seen in samples of active galactic nuclei is considered. We find that the cause of the peaked spectrum in PKS 1718-649 is most likely due to free–free absorption. In agreement with previous studies, we find that the spectrum at each epoch of observation is best fit by a free–free absorption model characterized by a power-law distribution of free–free absorbing clouds. This agreement is extended to frequencies below the 1 GHz lower limit of the ATCA by considering new observations with Parkes at 725 MHz and 199 MHz observations with the newly operational Murchison Widefield Array. These lower frequency observations argue against families of absorption models (both free–free and synchrotron self-absorption) that are based on simple homogenous structures.

  5. computational-structural-mechanics-training

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Table of Contents Date Location Training Course: HyperMesh and HyperView April 12-14, 2011 Argonne TRACC Argonne, IL Introductory Course: Developing Compute-efficient, Quality Models with LS-PrePost® 3 on the TRACC Cluster October 21-22, 2010 Argonne TRACC West Chicago, IL Modeling and Simulation with LS-DYNA®: Insights into Modeling with a Goal of Providing Credible Predictive Simulations February 11-12, 2010 Argonne TRACC West Chicago, IL Introductory Course: Using LS-OPT® on the TRACC

  6. Application of high performance computing to automotive design and manufacturing: Composite materials modeling task technical manual for constitutive models for glass fiber-polymer matrix composites

    SciTech Connect (OSTI)

    Simunovic, S; Zacharia, T

    1997-11-01

    This report provides a theoretical background for three constitutive models for a continuous strand mat (CSM) glass fiber-thermoset polymer matrix composite. The models were developed during fiscal years 1994 through 1997 as a part of the Cooperative Research and Development Agreement, "Application of High-Performance Computing to Automotive Design and Manufacturing." The full derivation of constitutive relations in the framework of the continuum program DYNA3D and have been used for the simulation and impact analysis of CSM composite tubes. The analysis of simulation and experimental results show that the model based on strain tensor split yields the most accurate results of the three implemented models. The parameters used in the models and their derivation from the physical tests are documented.

  7. Diffusion Dominant Solute Transport Modelling in Fractured Media Under Deep Geological Environment - 12211

    SciTech Connect (OSTI)

    Kwong, S.; Jivkov, A.P.

    2012-07-01

    Deep geologic disposal of high activity and long-lived radioactive waste is gaining increasing support in many countries, where suitable low permeability geological formation in combination with engineered barriers are used to provide long term waste contaminant and minimise the impacts to the environment and risk to the biosphere. This modelling study examines the solute transport in fractured media under low flow velocities that are relevant to a deep geological environment. In particular, reactive solute transport through fractured media is studied using a 2-D model, that considers advection and diffusion, to explore the coupled effects of kinetic and equilibrium chemical processes. The effects of water velocity in the fracture, matrix porosity and diffusion on solute transport are investigated and discussed. Some illustrative modelled results are presented to demonstrate the use of the model to examine the effects of media degradation on solute transport, under the influences of hydrogeological (diffusion dominant) and microbially mediated chemical processes. The challenges facing the prediction of long term degradation such as cracks evolution, interaction and coalescence are highlighted. The potential of a novel microstructure informed modelling approach to account for these effects is discussed, particularly with respect to investigating multiple phenomena impact on material performance. The GRM code is used to examine the effects of media degradation for a geological waste disposal package, under the combined hydrogeological (diffusion dominant) and chemical effects in low groundwater flow conditions that are typical of deep geological disposal systems. An illustrative reactive transport modelling application demonstrates the use of the code to examine the interplay of kinetic controlled biogeochemical reactive processes with advective and diffusive transport, under the influence of media degradation. The initial model results are encouraging which show the disposal system to evolve in a physically realistic manner. In the example presented the reactive-transport coupling develops chemically reducing zones, which limit the transport of uranium. This illustrates the potential significance of media degradation and chemical effect on the transport of radionuclides which would need to be taken into account when examining the long-term behaviour and containment properties of the geological disposal system. Microstructure-informed modelling and its potential linkage with continuum flow modelling is a subject of ongoing studies. The approach of microstructure-informed modelling is discussed to provide insight and a mechanistic understanding of macroscopic parameters and their evolution. The proposed theoretical and methodological basis for microstructure-informed modelling of porous quasi-brittle media has the potential to develop into an explanatory and predictive tool for deriving mechanism-based, as opposed to phenomenological, evolution laws for macroscopic properties. These concepts in micro-scale modelling are likely to be applicable to the diffusion process, in addition to advective transport illustrated here for porous media. (authors)

  8. Systems Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... Model Nambe Pueblo Water Budget Model Hydrogen Futures Simulations Model Barton Springs ... & Analysis Project Algae Biofuels Techno-Economic Modeling and Analysis Project Climate ...

  9. Concentrating Solar Power: Efficiently Leveraging Equilibrium Mechanisms

    Office of Environmental Management (EM)

    for Engineering New Thermochemical Storage | Department of Energy Power: Efficiently Leveraging Equilibrium Mechanisms for Engineering New Thermochemical Storage Concentrating Solar Power: Efficiently Leveraging Equilibrium Mechanisms for Engineering New Thermochemical Storage Concentrating Solar Power: Efficiently Leveraging Equilibrium Mechanisms for Engineering New Thermochemical Storage The Concentrating Solar Power: Efficiently Leveraging Equilibrium Mechanisms for Engineering New

  10. DOE fundamentals handbook: Mechanical science. Volume 2

    SciTech Connect (OSTI)

    Not Available

    1993-01-01

    The Mechanical Science Handbook was developed to assist nuclear facility operating contractors in providing operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of mechanical components and mechanical science. The handbook includes information diesel engines, heat exchangers, pumps, valves, and miscellaneous mechanical components. This information will provide personnel with a foundation for understanding the construction and operation of mechanical components that are associated with various DOE nuclear facility operations and maintenance.

  11. Controlled Thermo-Mechanical Processing

    SciTech Connect (OSTI)

    None

    2005-09-01

    The CTMP technology has the potential for widespread application in all major sectors of the domestic tube and pipe industry; two of the largest sectors are seamless mechanical tubing and seamless oil country tubular goods. It has been proven for the spheroidized annealing heat cycle for through-hardened steels and has led to the development of a recipe for automotive gear steels. Potential applications also exist in the smaller sectors of seamless line pipe, pressure tubing, and stainless tubing. The technology could also apply to non-ferrous metal industries, such as titanium.

  12. Detailed chemical kinetic oxidation mechanism for a biodiesel surrogate

    SciTech Connect (OSTI)

    Herbinet, O; Pitz, W J; Westbrook, C K

    2007-09-17

    A detailed chemical kinetic mechanism has been developed and used to study the oxidation of methyl decanoate, a surrogate for biodiesel fuels. This model has been built by following the rules established by Curran et al. for the oxidation of n-heptane and it includes all the reactions known to be pertinent to both low and high temperatures. Computed results have been compared with methyl decanoate experiments in an engine and oxidation of rapeseed oil methyl esters in a jet stirred reactor. An important feature of this mechanism is its ability to reproduce the early formation of carbon dioxide that is unique to biofuels and due to the presence of the ester group in the reactant. The model also predicts ignition delay times and OH profiles very close to observed values in shock tube experiments fueled by n-decane. These model capabilities indicate that large n-alkanes can be good surrogates for large methyl esters and biodiesel fuels to predict overall reactivity, but some kinetic details, including early CO2 production from biodiesel fuels, can be predicted only by a detailed kinetic mechanism for a true methyl ester fuel. The present methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.

  13. Detailed chemical kinetic oxidation mechanism for a biodiesel surrogate

    SciTech Connect (OSTI)

    Herbinet, O; Pitz, W J; Westbrook, C K

    2007-09-20

    A detailed chemical kinetic mechanism has been developed and used to study the oxidation of methyl decanoate, a surrogate for biodiesel fuels. This model has been built by following the rules established by Curran et al. for the oxidation of n-heptane and it includes all the reactions known to be pertinent to both low and high temperatures. Computed results have been compared with methyl decanoate experiments in an engine and oxidation of rapeseed oil methyl esters in a jet stirred reactor. An important feature of this mechanism is its ability to reproduce the early formation of carbon dioxide that is unique to biofuels and due to the presence of the ester group in the reactant. The model also predicts ignition delay times and OH profiles very close to observed values in shock tube experiments fueled by n-decane. These model capabilities indicate that large n-alkanes can be good surrogates for large methyl esters and biodiesel fuels to predict overall reactivity, but some kinetic details, including early CO{sub 2} production from biodiesel fuels, can be predicted only by a detailed kinetic mechanism for a true methyl ester fuel. The present methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.

  14. Detailed chemical kinetic oxidation mechanism for a biodiesel surrogate

    SciTech Connect (OSTI)

    Herbinet, Olivier; Pitz, William J.; Westbrook, Charles K.

    2008-08-15

    A detailed chemical kinetic mechanism has been developed and used to study the oxidation of methyl decanoate, a surrogate for biodiesel fuels. This model has been built by following the rules established by Curran and co-workers for the oxidation of n-heptane and it includes all the reactions known to be pertinent to both low and high temperatures. Computed results have been compared with methyl decanoate experiments in an engine and oxidation of rapeseed oil methyl esters in a jet-stirred reactor. An important feature of this mechanism is its ability to reproduce the early formation of carbon dioxide that is unique to biofuels and due to the presence of the ester group in the reactant. The model also predicts ignition delay times and OH profiles very close to observed values in shock tube experiments fueled by n-decane. These model capabilities indicate that large n-alkanes can be good surrogates for large methyl esters and biodiesel fuels to predict overall reactivity, but some kinetic details, including early CO{sub 2} production from biodiesel fuels, can be predicted only by a detailed kinetic mechanism for a true methyl ester fuel. The present methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels. (author)

  15. Density waves in the Calogero model - revisited

    SciTech Connect (OSTI)

    Bardek, V. Feinberg, J. Meljanac, S.

    2010-03-15

    The Calogero model bears, in the continuum limit, collective excitations in the form of density waves and solitary modulations of the density of particles. This sector of the spectrum of the model was investigated, mostly within the framework of collective-field theory, by several authors, over the past 15 years or so. In this work we shall concentrate on periodic solutions of the collective BPS-equation (also known as 'finite amplitude density waves'), as well as on periodic solutions of the full static variational equations which vanish periodically (also known as 'large amplitude density waves'). While these solutions are not new, we feel that our analysis and presentation add to the existing literature, as we explain in the text. In addition, we show that these solutions also occur in a certain two-family generalization of the Calogero model, at special points in parameter space. A compendium of useful identities associated with Hilbert transforms, including our own proofs of these identities, appears in Appendix A. In Appendix B we also elucidate in the present paper some fine points having to do with manipulating Hilbert-transforms, which appear ubiquitously in the collective field formalism. Finally, in order to make this paper self-contained, we briefly summarize in Appendix C basic facts about the collective field formulation of the Calogero model.

  16. Mechanisms of bacterially catalyzed reductive dehalogenation

    SciTech Connect (OSTI)

    Picardal, F.W.

    1992-12-31

    Nine bacteria were tested for the ability to dehalogenate tetrachloromethane (CT), tetrachloroethene (PCE), and 1, 1, 1-trichloroethane (TCA) under anaerobic conditions. Three bacteria were able to reductively dehalogenate CT. Dehalogenation ability was not readily linked to a common metabolism or changes in culture redox potential. None of the bacteria tested were able to dehalogenate PCE or TCA. One of the bacteria capable of dehalogenating CT, Shewanella putrefaciens, was chosen as a model organism to study mechanisms of bacterially catalyzed reductive dehalogenation. The effect of a variety of alternate electron acceptors on CT dehalogenation ability by S. putrefaciens was determined. oxygen and nitrogen oxides were inhibitory but Fe (III), trimethylamine oxide, and fumarate were not. A model of the electron transport chain of S. putrefaciens was developed to explain inhibition patterns. A period of microaerobic growth prior to CT exposure increased the ability of S. putrefaciens to dehalogenate CT. A microaerobic growth period also increased cytochrome concentrations. A relationship between cytochrome content and dehalogenation ability was developed from studies in which cytochrome concentrations in S. putrefaciens were manipulated by changing growth conditions. Stoichiometry studies using {sup 14}C-CT suggested that CT was first reduced to form a trichloromethyl radical. Reduction of the radical to produce chloroform and reaction of the radical with cellular biochemicals explained observed product distributions. Carbon dioxide or other fully dehalogenated products were not found.

  17. MECHANISMS AND OPTIMIZATION OF COAL COMBUSTION

    SciTech Connect (OSTI)

    Kyriacos Zygourakis

    2000-10-31

    The completed research project has made some significant contributions that will help us meet the challenges outlined in the previous section. One of the major novelties of our experimental approach involves the application of video microscopy and digital image analysis to study important transient phenomena (like particle swelling and ignitions) occurring during coal pyrolysis and combustion. Image analysis was also used to analyze the macropore structure of chars, a dominant factor in determining char reactivity and ignition behavior at high temperatures where all the commercial processes operate. By combining advanced experimental techniques with mathematical modeling, we were able to achieve the main objectives of our project. More specifically: (1) We accurately quantified the effect of several important process conditions (like pyrolysis heating rate, particle size, heat treatment temperature and soak time) on the combustion behavior of chars. These measurements shed new light into the fundamental mechanisms of important transient processes like particle swelling and ignitions. (2) We developed and tested theoretical models that can predict the ignition behavior of char particles and their burn-off times at high temperatures where intraparticle diffusional limitations are very important.

  18. Report on THMC Modeling of the Near Field Evolution of a Generic...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    field setting for modeling the geo-mechanical behavior of the buffer. The analysis highlights the complex coupled geo-mechanical behavior in the buffer and its...

  19. Bellcrank mechanisms for Stirling engines

    SciTech Connect (OSTI)

    Senft, J.R.; Senft, V.J.

    1996-12-31

    This paper describes a family of linkage drive systems for Stirling engines containing several new members. These mechanisms are adaptable to all three configurations of Stirling engine, impose minimal side loads on pistons and displacer rods, and include compact forms suitable for pressurized high performance engines. This group of drive systems is generated by a simple common scheme. Near sinusoidal motion is taken from a crankshaft carrying a single crankpin by two connecting rods each driving a bellcrank. The stationary pivots of the bellcranks are located so that their oscillatory motion has the phase angle separation required between the piston and displacer. The bellcranks are further configured to bring the third pin motion to a location suitable for coupling with the piston or displacer of the engine in a way which minimizes side loading. The paper presents a number of new linkage drives from the dual bellcrank family and indicates how they are embodied in beta and alpha type Stirling engines. The paper includes a design for a small multipurpose engine incorporating one of the subject mechanisms.

  20. High-Temperature Oxide Regrowth on Mechanically-Damaged Surfaces

    SciTech Connect (OSTI)

    Blau, Peter Julian; Lowe, Tracie M

    2008-01-01

    Here we report the effects of mechanical damage from a sharp stylus on the regrowth of oxide layers on a Ni-based superalloy known as Pyromet 80A . It was found that the oxide that reformed on the damaged portion of a pre-oxidized surface differed from that which formed on undamaged areas after the equal exposures to elevated temperature in air. These findings have broad implications for modeling the processes of material degradation in applications such as exhaust valves in internal combustion engines because they imply that static oxidation data for candidate materials may not adequately reflect their reaction to operating environments that involve both mechanical contact and oxidation.

  1. 2010 Thin Film & Small Scale Mechanical Behavior Gordon Research Conference

    SciTech Connect (OSTI)

    Dr. Thomas Balk

    2010-07-30

    Over the past decades, it has been well established that the mechanical behavior of materials changes when they are confined geometrically at least in one dimension to small scale. It is the aim of the 2010 Gordon Conference on 'Thin Film and Small Scale Mechanical Behavior' to discuss cutting-edge research on elastic, plastic and time-dependent deformation as well as degradation mechanisms like fracture, fatigue and wear at small scales. As in the past, the conference will benefit from contributions from fundamental studies of physical mechanisms linked to material science and engineering reaching towards application in modern applications ranging from optical and microelectronic devices and nano- or micro-electrical mechanical systems to devices for energy production and storage. The conference will feature entirely new testing methodologies and in situ measurements as well as recent progress in atomistic and micromechanical modeling. Particularly, emerging topics in the area of energy conversion and storage, such as material for batteries will be highlighted. The study of small-scale mechanical phenomena in systems related to energy production, conversion or storage offer an enticing opportunity to materials scientists, who can provide new insight and investigate these phenomena with methods that have not previously been exploited.

  2. Mathematically Reduced Chemical Reaction Mechanism Using Neural Networks

    SciTech Connect (OSTI)

    Ziaul Huque

    2007-08-31

    This is the final technical report for the project titled 'Mathematically Reduced Chemical Reaction Mechanism Using Neural Networks'. The aim of the project was to develop an efficient chemistry model for combustion simulations. The reduced chemistry model was developed mathematically without the need of having extensive knowledge of the chemistry involved. To aid in the development of the model, Neural Networks (NN) was used via a new network topology known as Non-linear Principal Components Analysis (NPCA). A commonly used Multilayer Perceptron Neural Network (MLP-NN) was modified to implement NPCA-NN. The training rate of NPCA-NN was improved with the GEneralized Regression Neural Network (GRNN) based on kernel smoothing techniques. Kernel smoothing provides a simple way of finding structure in data set without the imposition of a parametric model. The trajectory data of the reaction mechanism was generated based on the optimization techniques of genetic algorithm (GA). The NPCA-NN algorithm was then used for the reduction of Dimethyl Ether (DME) mechanism. DME is a recently discovered fuel made from natural gas, (and other feedstock such as coal, biomass, and urban wastes) which can be used in compression ignition engines as a substitute for diesel. An in-house two-dimensional Computational Fluid Dynamics (CFD) code was developed based on Meshfree technique and time marching solution algorithm. The project also provided valuable research experience to two graduate students.

  3. Miniature mechanical transfer optical coupler

    DOE Patents [OSTI]

    Abel, Philip (Overland Park, KS); Watterson, Carl (Kansas City, MO)

    2011-02-15

    A miniature mechanical transfer (MT) optical coupler ("MMTOC") for optically connecting a first plurality of optical fibers with at least one other plurality of optical fibers. The MMTOC may comprise a beam splitting element, a plurality of collimating lenses, and a plurality of alignment elements. The MMTOC may optically couple a first plurality of fibers disposed in a plurality of ferrules of a first MT connector with a second plurality of fibers disposed in a plurality of ferrules of a second MT connector and a third plurality of fibers disposed in a plurality of ferrules of a third MT connector. The beam splitting element may allow a portion of each beam of light from the first plurality of fibers to pass through to the second plurality of fibers and simultaneously reflect another portion of each beam of light from the first plurality of fibers to the third plurality of fibers.

  4. Technical abstracts: Mechanical engineering, 1990

    SciTech Connect (OSTI)

    Broesius, J.Y.

    1991-03-01

    This document is a compilation of the published, unclassified abstracts produced by mechanical engineers at Lawrence Livermore National Laboratory (LLNL) during the calendar year 1990. Many abstracts summarize work completed and published in report form. These are UCRL-JC series documents, which include the full text of articles to be published in journals and of papers to be presented at meetings, and UCID reports, which are informal documents. Not all UCIDs contain abstracts: short summaries were generated when abstracts were not included. Technical Abstracts also provides descriptions of those documents assigned to the UCRL-MI (miscellaneous) category. These are generally viewgraphs or photographs presented at meetings. An author index is provided at the back of this volume for cross referencing.

  5. Creep damage mechanisms in composites

    SciTech Connect (OSTI)

    Nutt, S.R.

    1994-10-17

    During the past year, research has focused on processing and characterization of intermetallic composites synthesized by plasma spray deposition. This versatile process allows rapid synthesis of a variety of different composite systems with potential applications for coatings, functionally gradient materials, rapid proto-typing and 3d printing, as well as near-net-shape processing of complex shapes. We have been pursuing an experimental program of research aimed at a fundamental understanding of the microstructural processes involved in the synthesis of intermetallic composites, including diffusion, heat transfer, grain boundary migration, and the dependence of these phenomena on deposition parameters. The work has been motivated by issues arising from composite materials manufacturing technologies. Recent progress is described in section B on the following topics: (1) Reactive atomization and deposition of intermetallic composites (Ni3Al); (2) Reactive synthesis of MoSi2-SiC composites; (3) Mechanical alloying of nanocrystalline alloys; (4) Tensile creep deformation of BMAS glass-ceramic composites.

  6. Plant salt-tolerance mechanisms

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Deinlein, Ulrich; Stephan, Aaron B.; Horie, Tomoaki; Luo, Wei; Xu, Guohua; Schroeder, Julian I.

    2014-06-01

    Crop performance is severely affected by high salt concentrations in soils. To engineer more salt-tolerant plants it is crucial to unravel the key components of the plant salt-tolerance network. Here we review our understanding of the core salt-tolerance mechanisms in plants. Recent studies have shown that stress sensing and signaling components can play important roles in regulating the plant salinity stress response. We also review key Na+ transport and detoxification pathways and the impact of epigenetic chromatin modifications on salinity tolerance. In addition, we discuss the progress that has been made towards engineering salt tolerance in crops, including marker-assisted selectionmore » and gene stacking techniques. We also identify key open questions that remain to be addressed in the future.« less

  7. Plant salt-tolerance mechanisms

    SciTech Connect (OSTI)

    Deinlein, Ulrich; Stephan, Aaron B.; Horie, Tomoaki; Luo, Wei; Xu, Guohua; Schroeder, Julian I.

    2014-06-01

    Crop performance is severely affected by high salt concentrations in soils. To engineer more salt-tolerant plants it is crucial to unravel the key components of the plant salt-tolerance network. Here we review our understanding of the core salt-tolerance mechanisms in plants. Recent studies have shown that stress sensing and signaling components can play important roles in regulating the plant salinity stress response. We also review key Na+ transport and detoxification pathways and the impact of epigenetic chromatin modifications on salinity tolerance. In addition, we discuss the progress that has been made towards engineering salt tolerance in crops, including marker-assisted selection and gene stacking techniques. We also identify key open questions that remain to be addressed in the future.

  8. Statistical Mechanics of Prion Diseases (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Statistical Mechanics of Prion Diseases Citation Details In-Document Search Title: Statistical Mechanics of Prion Diseases We present a two-dimensional, lattice based, protein-level statistical mechanical model for prion diseases (e.g., mad cow disease) with concomitant prion protein misfolding and aggregation. Our studies lead us to the hypothesis that the observed broad incubation time distribution in epidemiological data reflect fluctuation dominated growth seeded by a few nanometer scale

  9. Scalable computations in penetration mechanics

    SciTech Connect (OSTI)

    Kimsey, K.D.; Schraml, S.J.; Hertel, E.S.

    1998-01-01

    This paper presents an overview of an explicit message passing paradigm for an Eulerian finite volume method for modeling solid dynamics problems involving shock wave propagation, multiple materials, and large deformations. Three-dimensional simulations of high-velocity impact were conducted on the IBM SP2, the SGI Power challenge Array, and the SGI Origin 2000. The scalability of the message-passing code on distributed-memory and symmetric multiprocessor architectures is presented and compared to the ideal linear performance.

  10. Apparatus and method for generating mechanical waves

    DOE Patents [OSTI]

    Allensworth, D.L.; Chen, P.J.

    1982-10-25

    Mechanical waves are generated in a medium by subjecting an electromechanical element to an alternating electric field having a frequency which induces mechanical resonance therein and is below any electrical resonance frequency thereof.

  11. Apparatus and method for generating mechanical waves

    DOE Patents [OSTI]

    Allensworth, Dwight L. (Albuquerque, NM); Chen, Peter J. (Albuquerque, NM)

    1985-01-01

    Mechanical waves are generated in a medium by subjecting an electromechanical element to an alternating electric field having a frequency which induces mechanical resonance therein and is below any electrical resonance frequency thereof.

  12. Mechanical properties and tribological behavior of contaminate...

    Office of Scientific and Technical Information (OSTI)

    behavior of contaminate nanoparticles on micromachined surfaces. Citation Details In-Document Search Title: Mechanical properties and tribological behavior of ...

  13. Training: Mechanical Insulation | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Mechanical Insulation Training: Mechanical Insulation April 16, 2014 - 6:34pm Addthis Learn about the diverse training sessions offered. The courses are taught by highly qualified instructors who have met rigorous standards. View additional plant-wide resources. Mechanical Insulation Education and Awareness E-Learning Series Availability: Online self-paced workshop. The Mechanical Insulation Education & Awareness Campaign, or MIC, is an eLearning series offered by the U.S. Department of

  14. Mechanical Engineer | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanical Engineer Department: Engineering Supervisor(s): Bill Blanchard Staff: EM 3 Requisition Number: 1500 The Mechanical Design Engineer will develop, design, manufacture, and test mechanical components and auxiliary systems required for support of the experimental devices. The engineer will also design, specify, fabricate, and erect various mechanical structures to provide support against gravitational and electromagnetic forces. The position requires knowledge of stress analysis, magnetic

  15. Modeling ramp compression experiments using large-scale molecular dynamics simulation.

    SciTech Connect (OSTI)

    Mattsson, Thomas Kjell Rene; Desjarlais, Michael Paul; Grest, Gary Stephen; Templeton, Jeremy Alan; Thompson, Aidan Patrick; Jones, Reese E.; Zimmerman, Jonathan A.; Baskes, Michael I.; Winey, J. Michael; Gupta, Yogendra Mohan; Lane, J. Matthew D.; Ditmire, Todd; Quevedo, Hernan J.

    2011-10-01

    Molecular dynamics simulation (MD) is an invaluable tool for studying problems sensitive to atomscale physics such as structural transitions, discontinuous interfaces, non-equilibrium dynamics, and elastic-plastic deformation. In order to apply this method to modeling of ramp-compression experiments, several challenges must be overcome: accuracy of interatomic potentials, length- and time-scales, and extraction of continuum quantities. We have completed a 3 year LDRD project with the goal of developing molecular dynamics simulation capabilities for modeling the response of materials to ramp compression. The techniques we have developed fall in to three categories (i) molecular dynamics methods (ii) interatomic potentials (iii) calculation of continuum variables. Highlights include the development of an accurate interatomic potential describing shock-melting of Beryllium, a scaling technique for modeling slow ramp compression experiments using fast ramp MD simulations, and a technique for extracting plastic strain from MD simulations. All of these methods have been implemented in Sandia's LAMMPS MD code, ensuring their widespread availability to dynamic materials research at Sandia and elsewhere.

  16. Mesoscale Modeling of Fuel Swelling and Restructuring: Coupling

    Office of Scientific and Technical Information (OSTI)

    Microstructure evolution and Mechanical Localization. (Conference) | SciTech Connect Conference: Mesoscale Modeling of Fuel Swelling and Restructuring: Coupling Microstructure evolution and Mechanical Localization. Citation Details In-Document Search Title: Mesoscale Modeling of Fuel Swelling and Restructuring: Coupling Microstructure evolution and Mechanical Localization. Abstract not provided. Authors: Dingreville, Remi Philippe Michel ; Robbins, Joshua ; Bartel, Timothy James Publication

  17. A Key Role for Dimension in the Neutrino Mechanism of Core-Collapse...

    Office of Scientific and Technical Information (OSTI)

    in the viability of the neutrino mechanism of core-collapse explosions. In this talk, I will review the state of the field and the contending explosion models. In the...

  18. Computational thermal, chemical, fluid, and solid mechanics for geosystems management.

    SciTech Connect (OSTI)

    Davison, Scott; Alger, Nicholas; Turner, Daniel Zack; Subia, Samuel Ramirez; Carnes, Brian; Martinez, Mario J.; Notz, Patrick K.; Klise, Katherine A.; Stone, Charles Michael; Field, Richard V., Jr.; Newell, Pania; Jove-Colon, Carlos F.; Red-Horse, John Robert; Bishop, Joseph E.; Dewers, Thomas A.; Hopkins, Polly L.; Mesh, Mikhail; Bean, James E.; Moffat, Harry K.; Yoon, Hongkyu

    2011-09-01

    This document summarizes research performed under the SNL LDRD entitled - Computational Mechanics for Geosystems Management to Support the Energy and Natural Resources Mission. The main accomplishment was development of a foundational SNL capability for computational thermal, chemical, fluid, and solid mechanics analysis of geosystems. The code was developed within the SNL Sierra software system. This report summarizes the capabilities of the simulation code and the supporting research and development conducted under this LDRD. The main goal of this project was the development of a foundational capability for coupled thermal, hydrological, mechanical, chemical (THMC) simulation of heterogeneous geosystems utilizing massively parallel processing. To solve these complex issues, this project integrated research in numerical mathematics and algorithms for chemically reactive multiphase systems with computer science research in adaptive coupled solution control and framework architecture. This report summarizes and demonstrates the capabilities that were developed together with the supporting research underlying the models. Key accomplishments are: (1) General capability for modeling nonisothermal, multiphase, multicomponent flow in heterogeneous porous geologic materials; (2) General capability to model multiphase reactive transport of species in heterogeneous porous media; (3) Constitutive models for describing real, general geomaterials under multiphase conditions utilizing laboratory data; (4) General capability to couple nonisothermal reactive flow with geomechanics (THMC); (5) Phase behavior thermodynamics for the CO2-H2O-NaCl system. General implementation enables modeling of other fluid mixtures. Adaptive look-up tables enable thermodynamic capability to other simulators; (6) Capability for statistical modeling of heterogeneity in geologic materials; and (7) Simulator utilizes unstructured grids on parallel processing computers.

  19. Chemical kinetics modeling

    SciTech Connect (OSTI)

    Westbrook, C.K.; Pitz, W.J.

    1993-12-01

    This project emphasizes numerical modeling of chemical kinetics of combustion, including applications in both practical combustion systems and in controlled laboratory experiments. Elementary reaction rate parameters are combined into mechanisms which then describe the overall reaction of the fuels being studied. Detailed sensitivity analyses are used to identify those reaction rates and product species distributions to which the results are most sensitive and therefore warrant the greatest attention from other experimental and theoretical research programs. Experimental data from a variety of environments are combined together to validate the reaction mechanisms, including results from laminar flames, shock tubes, flow systems, detonations, and even internal combustion engines.

  20. Understanding Mechanisms of Radiological Contamination

    SciTech Connect (OSTI)

    Rick Demmer; John Drake; Ryan James, PhD

    2014-03-01

    Over the last 50 years, the study of radiological contamination and decontamination has expanded significantly. This paper addresses the mechanisms of radiological contamination that have been reported and then discusses which methods have recently been used during performance testing of several different decontamination technologies. About twenty years ago the Idaho Nuclear Technology Engineering Center (INTEC) at the INL began a search for decontamination processes which could minimize secondary waste. In order to test the effectiveness of these decontamination technologies, a new simulated contamination, termed SIMCON, was developed. SIMCON was designed to replicate the types of contamination found on stainless steel, spent fuel processing equipment. Ten years later, the INL began research into methods for simulating urban contamination resulting from a radiological dispersal device (RDD). This work was sponsored by the Defense Advanced Research Projects Agency (DARPA) and included the initial development an aqueous application of contaminant to substrate. Since 2007, research sponsored by the US Environmental Protection Agency (EPA) has advanced that effort and led to the development of a contamination method that simulates particulate fallout from an Improvised Nuclear Device (IND). The IND method diverges from previous efforts to create tenacious contamination by simulating a reproducible loose contamination. Examining these different types of contamination (and subsequent decontamination processes), which have included several different radionuclides and substrates, sheds light on contamination processes that occur throughout the nuclear industry and in the urban environment.

  1. Heavy Element Synthesis Reaction Mechanisms W. Loveland Oregon State University

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Reaction Mechanisms W. Loveland Oregon State University Production of Heavy Elements in Complete Fusion Reactions * We need to know three spin-dependent quantities: (a) the capture cross section, (b) the fusion probability and (c) the survival probability, and their isospin dependence where Examples of cold fusion predictions The problem Hot fusion examples "How good are the model predictions of cross sections" * Very controversial Zagrebaev and Greiner (2015) Zagrebaev et al. (2001)

  2. Methods of quantum mechanics applied to partially coherent light beams

    SciTech Connect (OSTI)

    Gase, R.

    1994-07-01

    Whenever the natural modes of the modal expansion of the cross-spectral density have a common waist, the wave equation in the waist plane has the form of a two-dimensional Schroedinger equation. Thus the results of quantum mechanics and quantum statistics, including the quantized Schroedinger field, can be transferred to partially coherent light. Such conceptions as temperature, entropy, and energy are used advantageously. A subclass of radiation, radiation in thermal equilibrium, is introduced, and, as examples, the Gaussian Schell-model beam and the quasi-rectangle model beam are investigated. The M{sup 2} factor is strongly related to the mean value of energy. 29 refs., 3 figs.

  3. Connecting the Molecular and the Continuum Scales

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    range of phenomena, from climate change to contaminant remediation. Accomplishments: Used molecular dynamics (MD) simulations to determine molecular-scale diffusion coefficients of...

  4. CODY: Continuum Dynamics Evaluation and Test Suite

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    computer architectures. Our goals are operating system, computer architecture, and programming language agnostic, however, so we expect evolution over time. CODY is designed...

  5. NREL: Continuum Magazine - Connecting the Moving Dots

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Zhang. "That makes the biorefinery designs more feasible for commercialization because air pollution permits are an absolute requirement for operation." Air Emissions-Mitigation...

  6. Improved Scheme for Modeling Mass Transfer between Fracture and Matrix Continua with Particle Tracking Method

    SciTech Connect (OSTI)

    L. Pan; Y. Seol; G. Bodvarsson

    2004-04-29

    The dual-continuum random-walk particle tracking approach is an attractive simulation method for simulating transport in a fractured porous medium. In order to be truly successful for such a model, however, the key issue is to properly simulate the mass transfer between the fracture and matrix continua. In a recent paper, Pan and Bodvarsson (2002) proposed an improved scheme for simulating fracture-matrix mass transfer, by introducing the concept of activity range into the calculation of fracture-matrix particle-transfer probability. By comparing with analytical solutions, they showed that their scheme successfully captured the transient diffusion depth into the matrix without any additional subgrid (matrix) cells. This technical note presents an expansion of their scheme to cases in which significant water flow through the fracture-matrix interface exists. The dual-continuum particle tracker with this new scheme was found to be as accurate as a numerical model using a more detailed grid. The improved scheme can be readily incorporated into the existing particle-tracking code, while still maintaining the advantage of needing no additional matrix cells to capture transient features of particle penetration into the matrix.

  7. Giant Protease TPP II's Structure, Mechanism Uncovered

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Giant Protease TPP II's Structure, Mechanism Uncovered Giant Protease TPP II's Structure, Mechanism Uncovered Print Wednesday, 23 February 2011 00:00 Tripeptidyl peptidase II (TPP II), the largest known eukaryotic enzyme that breaks down proteins (a protease), is implicated in numerous cellular processes including the degradation of the endogenous satiety agent cholecystokinin-8, making TPP II a target in the treatment of obesity. To gain insight into this molecular machine's mechanisms of

  8. PROJECT PROFILE: Mechanically Stacked Hybrid Photovoltaic Tandems |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy Mechanically Stacked Hybrid Photovoltaic Tandems PROJECT PROFILE: Mechanically Stacked Hybrid Photovoltaic Tandems Funding Opportunity: SuNLaMP SunShot Subprogram: Photovoltaics Location: National Renewable Energy Laboratory, Golden, CO Amount Awarded: $999,999 Tandem cell architectures present a path toward higher module efficiencies over single junction designs. This project will develop a gallium indium phosphide (GaInP) on silicon mechanically stacked voltage-matched

  9. Eccentric crank variable compression ratio mechanism

    DOE Patents [OSTI]

    Lawrence, Keith Edward (Kobe, JP); Moser, William Elliott (Peoria, IL); Roozenboom, Stephan Donald (Washington, IL); Knox, Kevin Jay (Peoria, IL)

    2008-05-13

    A variable compression ratio mechanism for an internal combustion engine that has an engine block and a crankshaft is disclosed. The variable compression ratio mechanism has a plurality of eccentric disks configured to support the crankshaft. Each of the plurality of eccentric disks has at least one cylindrical portion annularly surrounded by the engine block. The variable compression ratio mechanism also has at least one actuator configured to rotate the plurality of eccentric disks.

  10. A Predictive Model of Fragmentation using Adaptive Mesh Refinement and a Hierarchical Material Model

    SciTech Connect (OSTI)

    Koniges, A E; Masters, N D; Fisher, A C; Anderson, R W; Eder, D C; Benson, D; Kaiser, T B; Gunney, B T; Wang, P; Maddox, B R; Hansen, J F; Kalantar, D H; Dixit, P; Jarmakani, H; Meyers, M A

    2009-03-03

    Fragmentation is a fundamental material process that naturally spans spatial scales from microscopic to macroscopic. We developed a mathematical framework using an innovative combination of hierarchical material modeling (HMM) and adaptive mesh refinement (AMR) to connect the continuum to microstructural regimes. This framework has been implemented in a new multi-physics, multi-scale, 3D simulation code, NIF ALE-AMR. New multi-material volume fraction and interface reconstruction algorithms were developed for this new code, which is leading the world effort in hydrodynamic simulations that combine AMR with ALE (Arbitrary Lagrangian-Eulerian) techniques. The interface reconstruction algorithm is also used to produce fragments following material failure. In general, the material strength and failure models have history vector components that must be advected along with other properties of the mesh during remap stage of the ALE hydrodynamics. The fragmentation models are validated against an electromagnetically driven expanding ring experiment and dedicated laser-based fragmentation experiments conducted at the Jupiter Laser Facility. As part of the exit plan, the NIF ALE-AMR code was applied to a number of fragmentation problems of interest to the National Ignition Facility (NIF). One example shows the added benefit of multi-material ALE-AMR that relaxes the requirement that material boundaries must be along mesh boundaries.

  11. Integrable modification of the critical Chalker-Coddington network model

    SciTech Connect (OSTI)

    Ikhlef, Yacine; Fendley, Paul; Cardy, John

    2011-10-01

    We consider the Chalker-Coddington network model for the integer quantum Hall effect, and examine the possibility of solving it exactly. In the supersymmetric path integral framework, we introduce a truncation procedure, leading to a series of well-defined two-dimensional loop models with two loop flavors. In the phase diagram of the first-order truncated model, we identify four integrable branches related to the dilute Birman-Wenzl-Murakami braid-monoid algebra and parameterized by the loop fugacity n. In the continuum limit, two of these branches (1,2) are described by a pair of decoupled copies of a Coulomb-gas theory, whereas the other two branches (3,4) couple the two loop flavors, and relate to an SU(2){sub r}xSU(2){sub r}/SU(2){sub 2r} Wess-Zumino-Witten (WZW) coset model for the particular values n=-2cos[{pi}/(r+2)], where r is a positive integer. The truncated Chalker-Coddington model is the n=0 point of branch 4. By numerical diagonalization, we find that its universality class is neither an analytic continuation of the WZW coset nor the universality class of the original Chalker-Coddington model. It constitutes rather an integrable, critical approximation to the latter.

  12. Thermal-Mechanical Technologies | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of thermal-mechanical research includes: Single and two phase heat transfer Nanomaterial synthesis Heat transfer fluids Engine and power electronics cooling Thermal energy...

  13. Cost Mechanisms | OpenEI Community

    Open Energy Info (EERE)

    Cost Mechanisms Home Kyoung's picture Submitted by Kyoung(150) Contributor 9 July, 2013 - 20:57 GRR 3rd Quarter - Stakeholder Update Meeting Alaska analysis appropriations...

  14. CRAD, Nuclear Facility Construction - Mechanical Equipment -...

    Broader source: Energy.gov (indexed) [DOE]

    Nuclear Facility Construction - Mechanical Equipment Installation, (HSS CRAD 45-53, Rev. 0) This Criteria Review and Approach Document (HSS CRAD 45-53) establishes review criteria...

  15. Mechanical Characterization of Fuel Injector Piezoactuators and...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Mechanical Characterization of Fuel Injector Piezoactuators and their Piezoceramics 2007 Diesel Engine-Efficiency & Emissions Research Conference (DEER 2007). 13-16 August, 2007,...

  16. Clean Development Mechanism Pipeline | Open Energy Information

    Open Energy Info (EERE)

    Clean Development Mechanism Pipeline AgencyCompany Organization: UNEP-Risoe Centre, United Nations Environment Programme Sector: Energy, Land Topics: Finance, Implementation,...

  17. Financing Mechanisms for Renewable Energy Projects | Department...

    Broader source: Energy.gov (indexed) [DOE]

    A variety of renewable energy financing mechanisms are available for federal agencies to help meet the 30% of electricity from renewable energy sources by 2025 target established...

  18. CONTROL OF MECHANICALLY ACTIVATED POLYMERSOME FUSION: FACTORS...

    Office of Scientific and Technical Information (OSTI)

    MECHANICALLY ACTIVATED POLYMERSOME FUSION: FACTORS AFFECTING FUSION. Henderson, Ian M.; Paxton, Walter F Abstract not provided. Sandia National Laboratories (SNL-NM), Albuquerque,...

  19. Distinct Mechanisms of Recognizing Endosomal Sorting Complex...

    Office of Scientific and Technical Information (OSTI)

    Distinct Mechanisms of Recognizing Endosomal Sorting Complex Required for Transport III (ESCRT-III) Protein IST1 by Different Microtubule Interacting and Trafficking (MIT) Domains...

  20. Giant Protease TPP II's Structure, Mechanism Uncovered

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    endogenous satiety agent cholecystokinin-8, making TPP II a target in the treatment of obesity. To gain insight into this molecular machine's mechanisms of activation and...

  1. Pore scale modeling of reactive transport involved in geologic CO2 sequestration

    SciTech Connect (OSTI)

    Kang, Qinjin; Lichtner, Peter C; Viswanathan, Hari S; Abdel-fattah, Amr I

    2009-01-01

    We apply a multi-component reactive transport lattice Boltzmann model developed in previolls studies to modeling the injection of a C02 saturated brine into various porous media structures at temperature T=25 and 80 C. The porous media are originally consisted of calcite. A chemical system consisting of Na+, Ca2+, Mg2+, H+, CO2(aq), and CI-is considered. The fluid flow, advection and diHusion of aqueous species, homogeneous reactions occurring in the bulk fluid, as weB as the dissolution of calcite and precipitation of dolomite are simulated at the pore scale. The effects of porous media structure on reactive transport are investigated. The results are compared with continuum scale modeling and the agreement and discrepancy are discussed. This work may shed some light on the fundamental physics occurring at the pore scale for reactive transport involved in geologic C02 sequestration.

  2. Atomic-scale mechanisms of helium bubble hardening in iron

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Osetskiy, Yury N.; Stoller, Roger E.

    2015-06-03

    Generation of helium due to (n,α) transmutation reactions changes the response of structural materials to neutron irradiation. The whole process of radiation damage evolution is affected by He accumulation and leads to significant changes in the material s properties. A population of nanometric He-filled bubbles affects mechanical properties and the impact can be quite significant because of their high density. Understanding how these basic mechanisms affect mechanical properties is necessary for predicting radiation effects. In this paper we present an extensive study of the interactions between a moving edge dislocation and bubbles using atomic-scale modeling. We focus on the effectmore » of He bubble size and He concentration inside bubbles. Thus, we found that ability of bubbles to act as an obstacle to dislocation motion is close to that of voids when the He-to-vacancy ratio is in the range from 0 to 1. A few simulations made at higher He contents demonstrated that the interaction mechanism is changed for over-pressurized bubbles and they become weaker obstacles. The results are discussed in light of post-irradiation materials testing.« less

  3. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lu, Chunsong; Liu, Yangang; Niu, Shengjie; Endo, Satoshi

    2014-12-17

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasingmore » scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.« less

  4. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

    SciTech Connect (OSTI)

    Lu, Chunsong; Liu, Yangang; Niu, Shengjie; Endo, Satoshi

    2014-12-17

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasing scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.

  5. Models for Battery Reliability and Lifetime

    SciTech Connect (OSTI)

    Smith, K.; Wood, E.; Santhanagopalan, S.; Kim, G. H.; Neubauer, J.; Pesaran, A.

    2014-03-01

    Models describing battery degradation physics are needed to more accurately understand how battery usage and next-generation battery designs can be optimized for performance and lifetime. Such lifetime models may also reduce the cost of battery aging experiments and shorten the time required to validate battery lifetime. Models for chemical degradation and mechanical stress are reviewed. Experimental analysis of aging data from a commercial iron-phosphate lithium-ion (Li-ion) cell elucidates the relative importance of several mechanical stress-induced degradation mechanisms.

  6. Programming models

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Task-based models Task-based models and abstractions (such as offered by CHARM++, Legion and HPX, for example) offer many attractive features for mapping computations onto...

  7. Durability Improvements Through Degradation Mechanism Studies | Department

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    of Energy Improvements Through Degradation Mechanism Studies Durability Improvements Through Degradation Mechanism Studies Presented at the Department of Energy Fuel Cell Projects Kickoff Meeting, September 1 - October 1, 2009 PDF icon borup_lanl_kickoff.pdf More Documents & Publications FC-PAD Organization and Activities Fuel Cell Projects Kickoff Meeting The Science And Engineering of Duralbe Ultralow PGM Catalysts

  8. Thermoelectric Mechanical Reliability | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    09 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon pm_10_wereszczak.pdf More Documents & Publications Thermoelectric Mechanical Reliability Thermoelectric Mechanical Reliability Thermoelectrics Theory and Structure

  9. Enhancement of mechanical properties of 123 superconductors

    DOE Patents [OSTI]

    Balachandran, U.

    1995-04-25

    A composition and method are disclosed of preparing YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T{sub c}. About 5-20% additions give rise to substantially improved mechanical properties.

  10. Enhancement of mechanical properties of 123 superconductors

    DOE Patents [OSTI]

    Balachandran, Uthamalingam (Hinsdale, IL)

    1995-01-01

    A composition and method of preparing YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T.sub.c. About 5-20% additions give rise to substantially improved mechanical properties.

  11. Noise propagation in hybrid models of nonlinear systems: The GinzburgLandau equation

    SciTech Connect (OSTI)

    Taverniers, Sren; Alexander, Francis J.; Tartakovsky, Daniel M.

    2014-04-01

    Every physical phenomenon can be described by multiple models with varying degrees of fidelity. The computational cost of higher fidelity models (e.g., molecular dynamics simulations) is invariably higher than that of their lower fidelity counterparts (e.g., a continuum model based on differential equations). While the former might not be suitable for large-scale simulations, the latter are not universally valid. Hybrid algorithms provide a compromise between the computational efficiency of a coarse-scale model and the representational accuracy of a fine-scale description. This is achieved by conducting a fine-scale computation in subdomains where it is absolutely required (e.g., due to a local breakdown of a continuum model) and coupling it with a coarse-scale computation in the rest of a computational domain. We analyze the effects of random fluctuations generated by the fine-scale component of a nonlinear hybrid on the hybrid's overall accuracy and stability. Two variants of the time-dependent GinzburgLandau equation (GLE) and their discrete representations provided by a nearest-neighbor Ising model serve as a computational testbed. Our analysis shows that coupling these descriptions in a one-dimensional simulation leads to erroneous results. Adding a random source term to the GLE provides accurate prediction of the mean behavior of the quantity of interest (magnetization). It also allows the two GLE variants to correctly capture the strength of the microscale fluctuations. Our work demonstrates the importance of fine-scale noise in hybrid simulations, and suggests the need for replacing an otherwise deterministic coarse-scale component of the hybrid with its stochastic counterpart.

  12. Self-Aligning Mirror Mechanism for Transmission Line Offset Correction...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Self-Aligning Mirror Mechanism for Transmission Line Offset Correction The Self-Aligning Mirror Mechanism for Transmission Line Offset Correction is a self-aligning mechanism which...

  13. Defining the Mechanisms of Friction: A Grand Challenge in Interfacial...

    Office of Scientific and Technical Information (OSTI)

    Defining the Mechanisms of Friction: A Grand Challenge in Interfacial Mechanics. Citation Details In-Document Search Title: Defining the Mechanisms of Friction: A Grand Challenge...

  14. Kinetics, Mechanics and Microstructure Changes in Storage Media...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Kinetics, Mechanics and Microstructure Changes in Storage Media Kinetics, Mechanics and Microstructure Changes in Storage Media Presentation on the Kinetics, Mechanics and ...

  15. TEC Working Group Topic Groups Archives Mechanics of Funding...

    Office of Environmental Management (EM)

    Mechanics of Funding and Techical Assistance TEC Working Group Topic Groups Archives Mechanics of Funding and Techical Assistance Mechanics of Funding and Techical Assistance Items...

  16. Unitarity check in gravitational Higgs mechanism Berezhiani,...

    Office of Scientific and Technical Information (OSTI)

    MODELS; PARTICLE MODELS; POSTULATED PARTICLES The effective field theory of massive gravity has long been formulated in a generally covariant way N. Arkani-Hamed, H. Georgi,...

  17. Modeling shear failure and permeability enhancement due to coupled...

    Office of Scientific and Technical Information (OSTI)

    model the coupled thermal-hydrologic-mechanical (THM) processes in fractured geological formations is critical in effective EGS reservoir development and management strategies. ...

  18. Global Trade and Analysis Project (GTAP) Model | Open Energy...

    Open Energy Info (EERE)

    standard model. In addition, GTAP-E incorporates carbon emissions from the combustion of fossil fuels and provides for a mechanism to trade these emissions internationally. When...

  19. Assessment of Combustion and Turbulence Models for the Simulation...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Various applied combustion and turbulence models were investigated along with chemical kinetic mechanisms simulating a biodiesel-fueled engine PDF icon deer09ren.pdf More ...

  20. NREL: Energy Storage - Energy Storage Modeling and Simulation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    The lab's state-of-the-art multi-physics models are used to examine thermal, electrical, electrochemical, chemical, and mechanical behavior of energy storage cells and systems. ...