Powered by Deep Web Technologies
Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Damage and fatigue Continuum damage mechanics modeling  

E-Print Network [OSTI]

-CL�S : endommagement, fatigue, métaux, béton, élastomères, roche REGC ­ 10/2006. Geomechanics in energy production, pages 849 to 877 #12;850 REGC ­ 10/2006. Geomechanics in energy production 1. Introduction Continuum

2

A Continuum Coupled Moisture-mechanical Constitutive Model for Asphalt Concrete  

E-Print Network [OSTI]

constitutive relationships are implemented in the Pavement Analysis using Nonlinear Damage Approach (PANDA) finite element (FE) package to model the moisture damage effect on the complex environmental-mechanical response of asphalt concrete. The developed...

Shakiba, Maryam

2013-12-09T23:59:59.000Z

3

Cluster-continuum quantum mechanical models to guide the choice of anions for Li{sup +}-conducting ionomers  

SciTech Connect (OSTI)

A quantum-mechanical investigation on Li poly(ethylene oxide)-based ionomers was performed in the cluster-continuum solvation model (CCM) that includes specific solvation in the first shell surrounding the cation, all surrounded by a polarizable continuum. A four-state model, including a free Li cation, Li{sup +}-anion pair, triple ion, and quadrupole was used to represent the states of Li{sup +} within the ionomer in the CCM. The relative energy of each state was calculated for Li{sup +} with various anions, with dimethyl ether representing the ether oxygen solvation. The population distribution of Li{sup +} ions among states was estimated by applying Boltzmann statistics to the CCM energies. Entropy difference estimates are needed for populations to better match the true ionomer system. The total entropy change is considered to consist of four contributions: translational, rotational, electrostatic, and solvent immobilization entropies. The population of ion states is reported as a function of Bjerrum length divided by ion-pair separation with/without entropy considered to investigate the transition between states. Predicted concentrations of Li{sup +}-conducting states (free Li{sup +} and positive triple ions) are compared among a series of anions to indicate favorable features for design of an optimal Li{sup +}-conducting ionomer; the perfluorotetraphenylborate anion maximizes the conducting positive triple ion population among the series of anions considered.

Shiau, Huai-Suen; Janik, Michael J. [Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)] [Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Liu, Wenjuan; Colby, Ralph H. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)] [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2013-11-28T23:59:59.000Z

4

Fundamentals of mechanical behavior in structural intermetallics: A synthesis of atomistic and continuum modeling  

SciTech Connect (OSTI)

After a brief account of the recent advances in computational research on mechanical behavior of structural intermetallics, currently unresolved problems and critical issues are addressed and the knowledge base for potential answers to these problems is discussed. As large-scale problems (e.g., dislocation core structures, grain boundaries, and crack tips) are treated by atomistic simulations, future development of relevant interatomic potentials should be made consistent with the results of first-principles calculations. The bulk and defect properties calculated for intermetallic compounds, both known and as yet untested, can furnish insights to alloy designers in search of new high-temperature structural intermetallics.

Yoo, M.H.; Fu, C.L.

1993-08-01T23:59:59.000Z

5

Variational Theory of Mixtures in Continuum Mechanics  

E-Print Network [OSTI]

energy is assumed to be a function of densities, entropies and suc- cessive spatial gradients of each energy function of densities, entropies and spatial gradients, an equation describing the barycentric & Drumheller, 1983] cover most of the works in continuum theory. The book by Rowlinson & Swinton [1982] gives

Boyer, Edmond

6

Challenges in Continuum Modelling of Intergranular Fracture  

E-Print Network [OSTI]

Challenges in Continuum Modelling of Intergranular Fracture V. R. Coffman*, J. P. Sethna , A. R-2501, USA Cornell Fracture Group, Rhodes Hall, Cornell University, Ithaca, NY 14853-2501, USA § Department fracture in polycrystals is often simulated by finite elements coupled to a cohesive zone model

Sethna, James P.

7

Nano-Continuum Modeling of a Nuclear Glass Specimen Altered for 25 Years  

SciTech Connect (OSTI)

The purpose of this contribution is to report on preliminary nano-continuum scale modeling of nuclear waste glass corrosion. The focus of the modeling is an experiment involving a French glass SON68 specimen leached for 25 years in a granitic environment. In this report, we focus on capturing the nano-scale concentration profiles. We use a high resolution continuum model with a constant grid spacing of 1 nanometer to investigate the glass corrosion mechanisms.

Steefel, Carl

2014-01-06T23:59:59.000Z

8

Nano-Continuum Modeling of a Nuclear Glass Specimen Altered for 25 Years  

E-Print Network [OSTI]

Contract No. DE-AC02-05CH11231. Nano-Continuum Modeling of aNano-Continuum Modeling of a Nuclear Glass Specimen AlteredSignature on File) iv Nano-Continuum Modeling of a Nuclear

Steefel, Carl

2014-01-01T23:59:59.000Z

9

Studying the continuum limit of the Ising model  

Science Journals Connector (OSTI)

Different continuum limits of the Ising model in dimensions 2, 3, and 4 are investigated numerically. The data indicate that triviality occurs for D=4 and fails for D<4 in each limit.

Jae-Kwon Kim and Adrian Patrascioiu

1993-03-15T23:59:59.000Z

10

A Continuum Model for Carbon Nanotube-Infused Polyimides  

E-Print Network [OSTI]

A Continuum Model for Carbon Nanotube-Infused Polyimides Heather Wilson1 , Sumanth Banda2 , Ralph C, the materials need to withstand this process. The nanotube-infused polyimides are flexible enough to withstand

11

Continuum Modeling of Surface Relaxation Below the Roughening Temperature  

E-Print Network [OSTI]

Continuum Modeling of Surface Relaxation Below the Roughening Temperature Robert V. Kohn Courant of a crystalline surface below the roughening temperature: Surface consists of steps and terraces. Facets form Relaxation #12;Mullins' viewpoint Fourth-order PDE model is well-established for use above the roughening

Maryland at College Park, University of

12

To be submitted to Continuum Mechanics and Thermodynamics From the onset of damage to rupture: construction of responses with damage  

E-Print Network [OSTI]

To be submitted to Continuum Mechanics and Thermodynamics From the onset of damage to rupture: construction of responses with damage localization for a general class of gradient damage models Kim Pham solutions for the traction problem of an elastic damaging bar. This bar has a softening behavior which obeys

Boyer, Edmond

13

Applications of a new theory extending continuum mechanics to the nanoscale  

E-Print Network [OSTI]

In this dissertation, we present the Slattery-Oh-Fu theory extending continuum mechanics to the nanoscale and its applications. We begin with an analysis of supercritical adsorption of argon, krypton, and methane on Graphon before we fully develop...

Fu, Kaibin

2005-11-01T23:59:59.000Z

14

Continuum modeling of a neuronal cell under blast loading Antoine Jrusalem a,  

E-Print Network [OSTI]

2012 Keywords: Continuum model Neuron Blast Cell damage Traumatic brain injury a b s t r a cContinuum modeling of a neuronal cell under blast loading Antoine Jérusalem a, , Ming Dao b by proposing a continuum model of a neuronal cell submitted to blast loading. In this approach, the cytoplasm

Suresh, Subra

15

An Ordered Phase with Slow Decay of Correlations in Continuum 1=r 2 Ising Models  

E-Print Network [OSTI]

An Ordered Phase with Slow Decay of Correlations in Continuum 1=r 2 Ising Models Luiz R. G. Fontes@acf9.nyu.edu April 25, 1997 Abstract For continuum 1=r 2 Ising models, we prove that the critical value with slow decay of correlations. Our arguments involve comparisons be­ tween continuum and discrete Ising

16

Continuum mechanics beyond the second law of thermodynamics  

Science Journals Connector (OSTI)

...mechanics beyond the second law of thermodynamics M. Ostoja-Starzewski 1...thermoviscous fluid|second law of thermodynamics|fluctuation theorem|submartingale...developed subject to the second law of thermodynamics, requiring a non-negative...

2014-01-01T23:59:59.000Z

17

Continuum–discontinuum analysis of failure mechanisms around unsupported circular excavations in anisotropic clay shales  

Science Journals Connector (OSTI)

Abstract The stability of circular excavations in clay shales is a key issue in the drilling and tunnelling industries as well as in the field of deep geological waste storage. A large body of experimental evidence indicates that the damaged zone around these cavities is influenced by strong mechanical anisotropy induced by the layered material structure. The vast majority of numerical models adopted to date to analyse the stability of openings in layered rocks have been based on continuum mechanics principles using classic shear failure theory for elasto-plastic materials. However, a number of experimental observations demonstrate that clay shales may fail in a brittle manner under low-confinement conditions such as those characterizing the near-field of the excavation. Therefore, an alternative numerical approach based on non-linear fracture mechanics principles and the discrete element method is adopted to gain new insight into the failure process of this class of geomaterials. In order to account for the influence of clay shale microstructure on its mechanical behaviour a newly developed approach to capture the anisotropy of strength is proposed. With this numerical approach, the cohesive strength parameters of the fracture model are assumed to be a function of the relative orientation between the element bonds and the layering orientation. The effectiveness of the numerical technique is quantitatively demonstrated by simulating standard rock mechanics tests on an indurated claystone, namely Opalinus Clay. Emergent strength and deformation properties, together with the simulated fracture mechanisms, are shown to be in good agreement with experimental observations. The modelling technique is then applied to the simulation of the Excavation Damaged Zone (EDZ) around a circular tunnel in horizontally bedded Opalinus Clay. The simulated fracturing process is mainly discussed in the context of the damage mechanisms observed at the Mont Terri URL. Furthermore, the influence of in situ stress on resulting EDZ geometry is analysed together with possible implications for ground support and tunnel constructability. Modelling results highlight the importance of shear strength mobilization along bedding planes in controlling the EDZ formation process. In particular, slippage of bedding planes is shown to cause rock mass deconfinement which in turn promotes brittle failure processes in the form of spalling. The numerical technique is currently limited to two-dimensional analyses without any thermo-hydro-mechanical coupling.

A. Lisjak; G. Grasselli; T. Vietor

2014-01-01T23:59:59.000Z

18

Ad hoc continuum-atomistic thermostat for modeling heat flow in molecular dynamics simulations  

E-Print Network [OSTI]

Ad hoc continuum-atomistic thermostat for modeling heat flow in molecular dynamics simulations J 2004) An ad hoc thermostating procedure that couples a molecular dynamics (MD) simulation

Brenner, Donald W.

19

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

Broader source: Energy.gov [DOE]

THMC Modeling of EGS Reservoirs ? Continuum through Discontinuum Representations: Capturing Reservoir Stimulation, Evolution and Induced Seismicity presentation at the April 2013 peer review meeting held in Denver, Colorado.

20

Identification of material parameters for continuum modeling of phase transformations in multicomponent systems  

E-Print Network [OSTI]

Identification of material parameters for continuum modeling of phase transformations called order pa- rameters, which take on specified values in the bulk phases. If the transformation

Umantsev, Alexander

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Significance of decay mechanism into continuum in dynamical Wannier-Stark ladder  

SciTech Connect (OSTI)

We examine the resonance structure of photodressed electron states of laser-driven Wannier-Stark ladder, namely, dynamic Wannier-Stark ladder, in terms of the excess density of states (DOS) closely related to a lifetime of the state of concern. It is revealed that the resonance structure in the strong laser-field region shows clear dependence on the ratio, ?, of a Bloch-frequency to a laser frequency. As the laser strength increases, for ? = 1, the excess DOS becomes involved with a lot of newly-growing resonance peaks. This result would be understood from the viewpoint of a Fano-like decay-mechanism caused by a multichannel continuum effect, in marked contrast to the cases of larger ?’s; for ? = 3, the excess DOS just is found to show a pronounced red-shift of a single dominant peak caused by a single-channel continuum effect.

Nemoto, Yuya [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, 305-8573 (Japan); Maeshima, Nobuya; Hino, Ken-ichi [Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8573, Japan and Center for computational Sciences, University of Tsukuba, Tsukuba 305-8577 (Japan)

2013-12-04T23:59:59.000Z

22

A non-continuum approach to obtain a macroscopic model for the flow of traffic  

E-Print Network [OSTI]

by continuum models for the flow of traffic. The number of vehicles in a typical section of a freeway does not justify traffic being treated as a continuum. It is also important to recognize that the basic premises of kinetic theory are not appropriate...

Tyagi, Vipin

2007-09-17T23:59:59.000Z

23

A LARGE SCALE CONTINUUM-DISCRETE NUMERICAL MODELLING: APPLICATION TO OVERBURDEN DAMAGE OF A SALT CAVERN  

E-Print Network [OSTI]

CAVERN SOULEY Mountaka1 , MERCERAT Diego2 , DRIAD-LEBEAU Lynda1 , BERNARD Pascal2 1 INERIS, Ecole des collapse). KEYWORDS: cavern, numerical modelling, continuum-discrete, overburden, damage. RÃ?SUMÃ?: Dans l

Boyer, Edmond

24

THMC Modeling of EGS Reservoirs ? Continuum through Discontinuum...  

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

Accomplishments, Results and Progress Induced Seismicity - Model and Validation Fracture Geometry Stimulation Geometry Observed b-value 0.7-0.8 Event Distribution - by...

25

THMC Modeling of EGS Reservoirs ?Continuum through Discontinuum...  

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

Evolution and Induced Seismicity Derek Elsworth Pennsylvania State University Chemistry, Reservoir and Integrated Models May 19, 2010 This presentation does not contain any...

26

A continuum model of melt pond evolution on Arctic sea ice Daniela Flocco1  

E-Print Network [OSTI]

the atmosphere and ocean. In particular, sea ice affects the polar climate by insulating the ocean fromA continuum model of melt pond evolution on Arctic sea ice Daniela Flocco1 and Daniel L. Feltham1 the Northern Hemisphere summer, absorbed solar radiation melts snow and the upper surface of Arctic sea ice

Feltham, Daniel

27

A continuum constitutive model for amorphous metallic materials  

E-Print Network [OSTI]

A finite-deformation, Coulomb-Mohr type constitutive theory for the elastic-viscoplastic response of pressure-sensitive and plastically-dilatant isotropic materials has been developed. The constitutive model has been ...

Su, Cheng, Ph. D. Massachusetts Institute of Technology

2007-01-01T23:59:59.000Z

28

Weighted-density functionals for cavity formation and dispersion energies in continuum solvation models  

E-Print Network [OSTI]

Continuum solvation models enable efficient first principles calculations of chemical reactions in solution, but require extensive parametrization and fitting for each solvent and class of solute systems. Here, we examine the assumptions of continuum solvation models in detail and replace empirical terms with physical models in order to construct a minimally-empirical solvation model. Specifically, we derive solvent radii from the nonlocal dielectric response of the solvent from ab initio calculations, construct a closed-form and parameter-free weighted-density approximation for the free energy of the cavity formation, and employ a pair-potential approximation for the dispersion energy. We show that the resulting model with a single solvent-independent parameter: the electron density threshold ($n_c$), and a single solvent-dependent parameter: the dispersion scale factor ($s_6$), reproduces solvation energies of organic molecules in water, chloroform and carbon tetrachloride with RMS errors of 1.1, 0.6 and 0....

Sundararaman, Ravishankar; Arias, T A

2014-01-01T23:59:59.000Z

29

New Dynamic Models for Planar Extensible Continuum Robot Manipulators Enver Tatlicioglu, Ian D. Walker, and Darren M. Dawson  

E-Print Network [OSTI]

or an octopus arm [15]. It is a three-section robot with nine degrees of freedom where each section hasNew Dynamic Models for Planar Extensible Continuum Robot Manipulators Enver Tatlicioglu, Ian D 3-section extensible continuum robot manipulator. The results show a much stronger match to physical

30

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

SciTech Connect (OSTI)

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.

Mitran, Sorin, E-mail: mitran@unc.edu

2013-07-01T23:59:59.000Z

31

Multiscale micromechanical modeling of the thermal/mechanical properties of polymer/clay nanocomposites  

E-Print Network [OSTI]

Polymer/clay nanocomposites have been observed to exhibit enhanced thermal/mechanical properties at low weight fractions (We) of clay. Continuum-based composite modeling reveals that the enhanced properties are strongly ...

Sheng, Nuo, 1977-

2006-01-01T23:59:59.000Z

32

Spicing up continuum solvation models with SaLSA: the spherically-averaged liquid susceptibility ansatz  

E-Print Network [OSTI]

Continuum solvation models enable electronic structure calculations of systems in liquid environments, but because of the large number of empirical parameters, they are limited to the class of systems in their fit set (typically organic molecules). Here, we derive a solvation model with no empirical parameters for the dielectric response by taking the linear response limit of a classical density functional for molecular liquids. This model directly incorporates the nonlocal dielectric response of the liquid using an angular momentum expansion, and with a single fit parameter for dispersion contributions it predicts solvation energies of neutral molecules with an RMS error of 1.3 kcal/mol in water and 0.8 kcal/mol in chloroform and carbon tetrachloride. We show that this model is more accurate for strongly polar and charged systems than previous solvation models because of the parameter-free electric response, and demonstrate its suitability for ab initio solvation, including self-consistent solvation in quant...

Sundararaman, Ravishankar; Letchworth-Weaver, Kendra; Arias, T A

2014-01-01T23:59:59.000Z

33

Electric and magnetic response to the continuum for A=7 isobars in a dicluster model  

E-Print Network [OSTI]

Mirror isobars $^7$Li and $^7$Be are investigated in a dicluster model. The magnetic dipole moments and the magnetic dipole response to the continuum are calculated in this framework. The magnetic contribution is found to be small with respect to electric dipole and quadrupole excitations even at astrophysical energies, at a variance with the case of deuteron. Energy weighted molecular sum rules are evaluated and a formula for the molecular magnetic dipole sum rule is found which matches the numerical calculations. Cross-sections for photo-dissociation and radiative capture as well as the S-factor for reactions of astrophysical significance are calculated with good agreement with known experimental data.

A. Mason; R. Chatterjee; L. Fortunato; A. Vitturi

2008-11-11T23:59:59.000Z

34

A molecular model for Illinois No. 6 Argonne Premium coal: Moving toward capturing the continuum structure  

Science Journals Connector (OSTI)

A large-scale molecular model for Illinois No. 6 Argonne Premium coal is generated based on an automated construction approach in an effort to move toward capturing the continuum structure. The model contains 50,789 atoms within 728 molecules and is the largest, most complex coal representation constructed to-date. The aromatic ring size distribution was based on multiple high-resolution transmission electron microscope (HRTEM) lattice fringe micrographs and was duplicated with automated construction protocols (Fringe3D) in molecular modeling space. Additional structural data was obtained from the abundant literature assessing this Argonne Premium coal. Organic oxygen, nitrogen, and sulfur functionalities were incorporated primarily into the polyaromatic structures according to X-ray photoelectron spectroscopy and X-ray adsorption near-edge structure spectroscopy data. Aliphatic carbons were in the form of cross-links (bridges and loops) and pendant alkyl groups based on the combination of laser desorption ionization mass spectrometry (LDIMS), ruthenium ion catalyzed oxidation, elemental analysis, and NMR data in good agreement with the literature. Bound and bulk water was also included. Construction of the coal molecules was performed by use of Perl scripts developed in Materials Studio to eliminate personal bias and improve the accuracy and the scale of the structure generated. The large-scale model captured a broad and continuous molecular weight distribution in accordance with LDIMS data here ranging from 100 to 2850 Da, enabling inclusion of structural diversity to capture a portion of the continuum structure. A theoretical pyridine extraction yield, determined by a group contribution approach, was in agreement with the experimental value. The extract and residue representations were generated from the large-scale Illinois coal model and showed consistency with NMR, elemental analysis and LDIMS trends. The distribution of heteroatomic classes and double bond equivalents was also well-defined experimentally based on electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. These data further constrain the molecular weight of extractable material and was consistent with limited pyridine extractability and model heteroatom classes. Future work will be well served by staying within the limits established by the approach and increasing the structural diversity (sampling frequency through increased scale) to better capture the complex nature of coal structural diversity, i.e., the continuum.

Fidel Castro-Marcano; Vladislav V. Lobodin; Ryan P. Rodgers; Amy M. McKenna; Alan G. Marshall; Jonathan P. Mathews

2012-01-01T23:59:59.000Z

35

Surveying the Free Energy Landscapes of Continuum Models: Application to Soft Matter Systems  

E-Print Network [OSTI]

A variety of methods are developed for characterising the free energy landscapes of continuum, Landau-type free energy models. Using morphologies of lipid vesicles and a multistable liquid crystal device as examples, I show that the methods allow systematic study of not only the most relevant minimum energy configurations, but also the transition pathways between any two minima, as well as their corresponding energy barriers and transition state configurations. A global view of the free energy landscapes can then be visualized using either a disconnectivity graph or a network representation. Different forms of free energy functionals and boundary conditions can be readily implemented, thus allowing these tools to be utilised for a broad range of problems.

Kusumaatmaja, Halim

2015-01-01T23:59:59.000Z

36

Prediction of Damage Zone Growth in Composites Using Continuum Damage Mechanics  

E-Print Network [OSTI]

. Failure Criteria . . . . . . . . . . . . . . . . . . . . . . . . 26 B. Constitutive Degradation Model . . . . . . . . . . . . . . . 27 C. Implementation . . . . . . . . . . . . . . . . . . . . . . . . 29 IV CONFIGURATIONS... . . . . . . . . . . . . . . . . . . . . 34 4. Line of Degraded Elements . . . . . . . . . . . . . . . 35 B. Material Properties . . . . . . . . . . . . . . . . . . . . . . 36 V RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 A. Discrete Crack...

McLendon, Wesley R.

2010-07-14T23:59:59.000Z

37

Why Do Continuum Gas-Solids Flow Models Predict Core-Annulus Flow?  

SciTech Connect (OSTI)

Core-annulus flow is an experimentally well established, industrially significant flow pattern of circulating fluidized beds. Several studies reported in the literature have shown that continuum gas-solids flow models are able to predict that flow pattern. But the crucial features of the model that give rise to the core-annulus flow structure have not been identified. To determine those features, we conduct transient simulations and analyze the results. Furthermore we time-average the results and investigate the formulation of time-averaged equations. We use transient, highly resolved, 1-D, grid-independent numerical solutions of a continuum model in this study. We show that the results could be even qualitatively incorrect (high solids concentration at the center of the channel) unless grid-independence is established. This explains why in certain coarse grid computations reported in the literature it was necessary to remove a dissipation term or to increase the particle size. Our simulations verify that the core-annulus structure arises in a time-averaged sense from unsteady gas-solids flow, as observed in experiments. We show that the key term that makes the flow unsteady is the dissipation term in the granular energy equation. Without that term the simulation yields a steady-state solution. The intuition based on steady-state solutions may not be valid. Unlike steady-state solutions, the transient solutions are not unduly sensitive to the restitution coefficient. The effect of restitution coefficient in transient simulations is remarkably different: a smaller restitution coefficient gives a higher average granular temperature. Both the micro-scale (clusters resolved) and meso-scale (clusters time-averaged) phenomena are important, unlike turbulent single-phase flows where the meso-scale (turbulent) stresses dominate. The prediction of core-annulus flow is strongly affected by the parameters used in the (micro-scale) wall boundary conditions; it is essential that the parameters are such that no granular energy is produced at the wall. The normal stress based on kinetic theory (Ps, micro) is an order of magnitude larger than normal stress arising from fluctuations (Ps, meso). Therefore, the granular temperature and solids fraction are approximately inversely correlated, just as shown by a steady-state analysis. However, the gradient of Ps, micro is of the same order of magnitude as the gradient of Ps, meso; those gradients adjust to ensure that the time averaged total Ps gradient in the radial direction is zero. The meso-scale shear stress is larger than the micro-scale shear stress. The meso-scale granular energy production term dominates the corresponding micro-scale term and must be included in time-averaged equations. That term is responsible for the maximum at the center in the granular temperature profile. The micro-scale granular energy production term is identically zero at the center because it is proportional to the gradient of solids velocity, which is zero at the center. The instantaneous gradient of solids velocity at the center, however, is not zero because of the down flow of clusters near the walls; it takes positive and negative values making the time-averaged velocity gradient exactly zero at the center. Therefore, the time-averaged square of the velocity gradient is non-zero at the center, which results in a production term in the time-averaged equations that is non-zero at the center. We find that the predictions are insensitive to the currently available k-å type turbulence models. The traditional k-å type models, based on the experience with single phase flow calculations, may not be adequate because meso-scale terms do not necessarily dominate the micro-scale terms. And certain parameters could behave counter to our intuition based on single phase flows: we compute and confirm with physical arguments that the gas-phase turbulent (meso-scale) viscosity could become negative.

Benyahia, S.; Syamlal, M.; O'Brien, T.J.

2006-11-01T23:59:59.000Z

38

Nano-Continuum Modeling of a Nuclear Glass Specimen Altered for 25 Years  

E-Print Network [OSTI]

Insight into silicate-glass corrosion mechanisms. NatureSantarini (2008). SON68 nuclear glass dissolution kinetics:B. (2006). Nuclear waste glasses – How durable? Elements, 2,

Steefel, Carl

2014-01-01T23:59:59.000Z

39

Kinetics and mechanisms of metal sorption at the soil mineral/water interface: The continuum from adsorption to  

E-Print Network [OSTI]

GEOC 36 Kinetics and mechanisms of metal sorption at the soil mineral/water interface, Newark, DE 19717-1303 A basic understanding of the kinetics and mechanisms of metal sorption on natural conditions. Using these approaches, major advances have occurred in our understanding of metal sorption

Sparks, Donald L.

40

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.

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

On the equivalence of continuum and lattice models for uids Athanassios Z. Panagiotopoulos  

E-Print Network [OSTI]

translational order inappropriate for disordered phases. The simplest such model was proposed by Ising in 19251, particularly for modeling macromolecules such as synthetic polymers and proteins. For example, the bond transitions in proteins7. The present study was motivated by recent work9 on a simple cubic lattice version

42

Gas Kinetic Scheme for Continuum and Near-Continuum Hypersonic Flows  

E-Print Network [OSTI]

Gas Kinetic Scheme for Continuum and Near-Continuum Hypersonic Flows Wei Liao and Li-Shi Luo Old for the near-continuum flows. The gas-kinetic schemes are validated with simulations of the hypersonic flow thickness, modeling and simulation of complex hypersonic flows become very challenging for computational

Luo, Li-Shi

43

A continuum plasticity model for the constitutive behavior of foamed metals  

SciTech Connect (OSTI)

A yield surface is proposed that can be fit to the plastic flow properties of a broad class of solids which exhibit plastic compressibility and different yield points in tension and compression. The yield surface is proposed to describe cellular solids, including foamed metals, and designed to be fit to three simple experimental results: (1) the compressive stress-strain response (including densification), (2) the difference between the tensile and compressive yield points and (3) the degree of compressibility of the foam, as measured by the lateral expansion during a uniaxial compression test. The model is implemented using finite elements and used to study the effects of plastic compressibility on two problems: the compression of a doubly notched specimen and indentation by a spherical indenter.

Miller, R.E.; Hutchinson, J.W. [Harvard Univ., Cambridge, MA (United States). Div. of Applied Science

1998-12-31T23:59:59.000Z

44

The Quantized $O(1,2)/O(2)\\times Z_2$ Sigma Model Has No Continuum Limit in Four Dimensions. II. Lattice Simulation  

E-Print Network [OSTI]

A lattice formulation of the $O(1,2)/O(2)\\times Z_2$ sigma model is developed, based on the continuum theory presented in the preceding paper. Special attention is given to choosing a lattice action (the ``geodesic'' action) that is appropriate for fields having noncompact curved configuration spaces. A consistent continuum limit of the model exists only if the renormalized scale constant $\\beta_R$ vanishes for some value of the bare scale constant~$\\beta$. The geodesic action has a special form that allows direct access to the small-$\\beta$ limit. In this limit half of the degrees of freedom can be integrated out exactly. The remaining degrees of freedom are those of a compact model having a $\\beta$-independent action which is noteworthy in being unbounded from below yet yielding integrable averages. Both the exact action and the $\\beta$-independent action are used to obtain $\\beta_R$ from Monte Carlo computations of field-field averages (2-point functions) and current-current averages. Many consistency cross-checks are performed. It is found that there is no value of $\\beta$ for which $\\beta_R$ vanishes. This means that as the lattice cutoff is removed the theory becomes that of a pair of massless free fields. Because these fields have neither the geometry nor the symmetries of the original model we conclude that the $O(1,2)/O(2)\\times Z_2$ model has no continuum limit.

Jorge de Lyra; Bryce DeWitt; See Kit Foong; Timothy Gallivan; Rob Harrington; Arie Kapulkin; Eric Myers; Joeseph Polchinski

1992-05-22T23:59:59.000Z

45

The continuum and wave mechanics  

E-Print Network [OSTI]

S l + ( + * * - ? % ) } J * tlnSByncdny "LRby P is positive semi-definite we bDR YnLSy ? as the square dI some IlRbSLdR Then we note that LI we ayILRy SYd IlRbSLdRG -+ and by the y:lDSLdRG DRa - 2JU A (5i) f * = H e u we can write (52) P...

Collins, Royal Eugene

1954-01-01T23:59:59.000Z

46

Regulation mechanisms in spatial stochastic development models  

E-Print Network [OSTI]

The aim of this paper is to analyze different regulation mechanisms in spatial continuous stochastic development models. We describe the density behavior for models with global mortality and local establishment rates. We prove that the local self-regulation via a competition mechanism (density dependent mortality) may suppress a unbounded growth of the averaged density if the competition kernel is superstable.

Dmitri Finkelshtein; Yuri Kondratiev

2008-09-04T23:59:59.000Z

47

Modeling Control Mechanisms with Normative Multiagent Systems  

E-Print Network [OSTI]

. This paper is about control mechanisms for virtual organizations. As a case study, we discuss the Renewables of renewable energy. We apply a conceptual model based on normative multiagent systems (NMAS). We proposeModeling Control Mechanisms with Normative Multiagent Systems: the Case of the Renewables

van der Torre, Leon

48

Modeling the coupled mechanics, transport, and growth processes in collagen tissues.  

SciTech Connect (OSTI)

The purpose of this project is to develop tools to model and simulate the processes of self-assembly and growth in biological systems from the molecular to the continuum length scales. The model biological system chosen for the study is the tendon fiber which is composed mainly of Type I collagen fibrils. The macroscopic processes of self-assembly and growth at the fiber scale arise from microscopic processes at the fibrillar and molecular length scales. At these nano-scopic length scales, we employed molecular modeling and simulation method to characterize the mechanical behavior and stability of the collagen triple helix and the collagen fibril. To obtain the physical parameters governing mass transport in the tendon fiber we performed direct numerical simulations of fluid flow and solute transport through an idealized fibrillar microstructure. At the continuum scale, we developed a mixture theory approach for modeling the coupled processes of mechanical deformation, transport, and species inter-conversion involved in growth. In the mixture theory approach, the microstructure of the tissue is represented by the species concentration and transport and material parameters, obtained from fibril and molecular scale calculations, while the mechanical deformation, transport, and growth processes are governed by balance laws and constitutive relations developed within a thermodynamically consistent framework.

Holdych, David J.; Nguyen, Thao D.; Klein, Patrick A.; in't Veld, Pieter J.; Stevens, Mark Jackson

2006-11-01T23:59:59.000Z

49

Modeling the mechanical response of PBX 9501  

SciTech Connect (OSTI)

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.

Ragaswamy, Partha [Los Alamos National Laboratory; Lewis, Matthew W [Los Alamos National Laboratory; Liu, Cheng [Los Alamos National Laboratory; Thompson, Darla G [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

50

Mechanics of hydrogen storage in carbon nanotubes Y.L. Chen a  

E-Print Network [OSTI]

Mechanics of hydrogen storage in carbon nanotubes Y.L. Chen a , B. Liu a,Ã?, J. Wu a , Y. Huang b 17 July 2008 Keywords: Hydrogen storage Carbon nanotube Continuum model Analytical solution Atomistic simulations a b s t r a c t A continuum mechanics model is established for hydrogen storage in single

Jiang, Hanqing

51

Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro...  

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

Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined Electrodes Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined Electrodes 2010 DOE...

52

STATISTICAL MECHANICS: FROM ISING MODELS TO UNITARY MINIMAL MODELS  

E-Print Network [OSTI]

STATISTICAL MECHANICS: FROM ISING MODELS TO UNITARY MINIMAL MODELS Paul A. PEARCE Mathematics universality classes of critical behaviour including the critical and tricritical Ising model, the critical of a ferromagnet with his Ph.D. student Ising2 . This period gave birth to the subject of exactly solvable lattice

Pearce, Paul A.

53

Development of multicomponent hybrid density functional theory with polarizable continuum model for the analysis of nuclear quantum effect and solvent effect on NMR chemical shift  

SciTech Connect (OSTI)

We have developed the multicomponent hybrid density functional theory [MC-(HF+DFT)] method with polarizable continuum model (PCM) for the analysis of molecular properties including both nuclear quantum effect and solvent effect. The chemical shifts and H/D isotope shifts of the picolinic acid N-oxide (PANO) molecule in chloroform and acetonitrile solvents are applied by B3LYP electron exchange-correlation functional for our MC-(HF+DFT) method with PCM (MC-B3LYP/PCM). Our MC-B3LYP/PCM results for PANO are in reasonable agreement with the corresponding experimental chemical shifts and isotope shifts. We further investigated the applicability of our method for acetylacetone in several solvents.

Kanematsu, Yusuke; Tachikawa, Masanori [Quantum Chemistry Division, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027 (Japan)] [Quantum Chemistry Division, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027 (Japan)

2014-04-28T23:59:59.000Z

54

Collective excitations in the continuum  

Science Journals Connector (OSTI)

Pairing (particle-particle) giant resonances are analyzed within a shell-model formalism in the complex energy plane with the aim of understanding why they have not been observed so far. A comparison is made with the equivalent particle-hole mode by applying the formalism to the analysis of the well-understood particle-hole giant resonance. It is found that because of the proper treatment of the continuum intrinsic to the formalism, giant pairing resonances lie much higher than previously predicted and that some of them may be too wide to be observed, whereas others are meaningful excitations. For these, new experimental searches are proposed.

G. G. Dussel; R. Id Betan; R. J. Liotta; T. Vertse

2009-12-14T23:59:59.000Z

55

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

SciTech Connect (OSTI)

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.

Fok, Alex

2013-10-30T23:59:59.000Z

56

NREL: Continuum Magazine Home Page  

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

NREL Spectrum of Clean Energy Innovation NREL Spectrum of Clean Energy Innovation Issue 3 Print Version Share this resource Continuum Magazine Dan Says NREL Leads Wind Farm Modeling Research NREL Leads Wind Farm Modeling Research Researchers study the atmosphere surrounding large turbines to optimize performance. Driving Solar Innovations from Laboratory to Marketplace Driving Solar Innovations from Laboratory to Marketplace Disruptive innovation is making solar cost competitive with non-renewable energy. Reaping a Harvest of Hope Reaping a Harvest of Hope Five years after a devastating tornado, Greensburg, Kansas has new energy and a new outlook. Energy Innovation Portal Bridging Information Gap Energy Innovation Portal Bridging Information Gap Database revolutionizes intellectual property transfer from DOE's national

57

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

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

& Publications Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical Modeling Modeling - Scale-Bridging Simulations Active Materials in Li-ion Batteries,...

58

A Conceptual Approach to Two-Scale Constitutive Modelling For Hydro-Mechanical Coupling  

E-Print Network [OSTI]

Large scale modelling of fluid flow coupled with solid failure in geothermal reservoirs or hydrocarbon extraction from reservoir rocks usually involves behaviours at two scales: lower scale of the inelastic localization zone, and larger scale of the bulk continuum where elastic behaviour can be reasonably assumed. The hydraulic conductivities corresponding to the mechanical properties at these two scales are different. In the bulk elastic host rock, the hydraulic conductivity does not vary much with the deformation, while it significantly changes in the lower scale of the localization zone due to inelastic deformation. Increase of permeability due to fracture and/or dilation, or reduction of permeability due to material compaction can take place inside this zone. The challenge is to predict the evolution of hydraulic conductivities coupled with the mechanical behaviour of the material in all stages of the deformation process. In the early stage of diffuse deformation, the permeability of the material can be reasonably assumed to be homogenous over the whole Representative Volume Element (RVE) However, localized failure results in distinctly different conductivities in different parts of the RVE. This paper establishes a general framework and corresponding field equations to describe the hydro-mechanical coupling in both diffuse and localized stages of deformation in rocks. In particular, embedding the lower scale hydro-mechanical behaviour of the localization zone inside an elastic bulk, together with their corresponding effective sizes, helps effectively deal with scaling issues in large-scale modelling. Preliminary results are presented which demonstrate the promising features of this new approach.

Giang D. Nguyen; Abbas El-Zein; Terry Bennett

2014-06-05T23:59:59.000Z

59

NREL: Continuum Magazine Home Page  

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

6 Print Version Share this resource Continuum Magazine Dan Says NREL Provides a Foundation for Home Energy Performance NREL Provides a Foundation for Home Energy Performance...

60

Dynamic Analysis and Modeling of Jansen Mechanism  

Science Journals Connector (OSTI)

Abstract Theo Jansen mechanism is gaining wide spread popularity among legged robotics researchers due to its scalable design, energy efficiency, low payload to machine load ratio, bio-inspired locomotion, deterministic foot trajectory among others. In this paper, we present dynamic analysis of a four legged Theo Jansen link mechanism using projection method that results in constraint force and equivalent Lagrange's equation of motion necessary for any meaningful extension and/or optimization of this niche mechanism. Numerical simulations using MaTX is presented in conjunction with the dynamic analysis. This research sets a theoretical basis for future investigation into Theo Jansen mechanism.

Shunsuke Nansai; Mohan Rajesh Elara; Masami Iwase

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

LANL: Mechanical testing and modeling in MST  

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

etc.). As the effects of processing are to critical to accurate prediction of its mechanical behavior, MST hosts a range of metallographic and characterization tools. Specific...

62

A Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal...  

Open Energy Info (EERE)

to the most hydraulically conductive fractures in two orthogonal and vertical fracture sets. The mathematical model representing the hydro-mechanical interactions that are...

63

Continuum Limit of gl(M/N) Spin Chains  

E-Print Network [OSTI]

We study the spectrum of an integrable antiferromagnetic Hamiltonian of the gl(M|N) spin chain of alternating fundamental and dual representations. After extensive numerical analysis, we identify the vacuum and low lying excitations and with this knowledge perform the continuum limit, while keeping a finite gap. All gl(n+N|N) spin chains with n,N>0 are shown to possess in the continuum limit 2n-2 multiplets of massive particles which scatter with gl(n) Gross-Neveu like S-matrices, namely their eigenvalues do not depend on N. We argue that the continuum theory is the gl(M|N) Gross-Neveu model. We then look for remaining particles in the gl(2m|1) chains. The results suggest there is a continuum of such particles, which in order to be fully understood require finite volume calculations.

Candu, Constantin

2010-01-01T23:59:59.000Z

64

Continuum Limit of gl(M/N) Spin Chains  

E-Print Network [OSTI]

We study the spectrum of an integrable antiferromagnetic Hamiltonian of the gl(M|N) spin chain of alternating fundamental and dual representations. After extensive numerical analysis, we identify the vacuum and low lying excitations and with this knowledge perform the continuum limit, while keeping a finite gap. All gl(n+N|N) spin chains with n,N>0 are shown to possess in the continuum limit 2n-2 multiplets of massive particles which scatter with gl(n) Gross-Neveu like S-matrices, namely their eigenvalues do not depend on N. We argue that the continuum theory is the gl(M|N) Gross-Neveu model. We then look for remaining particles in the gl(2m|1) chains. The results suggest there is a continuum of such particles, which in order to be fully understood require finite volume calculations.

Constantin Candu

2010-11-30T23:59:59.000Z

65

MASSIVELY PARALLEL FULLY COUPLED IMPLICIT MODELING OF COUPLED THERMAL-HYDROLOGICAL-MECHANICAL PROCESSES FOR ENHANCED GEOTHERMAL SYSTEM RESERVOIRS  

SciTech Connect (OSTI)

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 system and our ability to reliably predict how reservoirs behave under stimulation and production. In order to increase our understanding of how reservoirs behave under these conditions, we have developed a physics-based rock deformation and fracture propagation simulator by coupling a discrete element model (DEM) for fracturing with a continuum multiphase flow and heat transport model. In DEM simulations, solid rock is represented by a network of discrete elements (often referred as particles) connected by various types of mechanical bonds such as springs, elastic beams or bonds that have more complex properties (such as stress-dependent elastic constants). Fracturing is represented explicitly as broken bonds (microcracks), which form and coalesce into macroscopic fractures when external load is applied. DEM models have been applied to a very wide range of fracturing processes from the molecular scale (where thermal fluctuations play an important role) to scales on the order of 1 km or greater. In this approach, the continuum flow and heat transport equations are solved on an underlying fixed finite element grid with evolving porosity and permeability for each grid cell that depends on the local structure of the discrete element network (such as DEM particle density). The fluid pressure gradient exerts forces on individual elements of the DEM network, which therefore deforms and fractures. Such deformation/fracturing in turn changes the permeability, which again changes the evolution of fluid pressure, coupling the two phenomena. The intimate coupling between fracturing and fluid flow makes the meso-scale DEM simulations necessary, as these methods have substantial advantages over conventional continuum mechanical models of elastic rock deformation. The challenges that must be overcome to simulate EGS reservoir stimulation, preliminary results, progress to date and near future research directions and opportunities will be discussed.

Robert Podgorney; Hai Huang; Derek Gaston

2010-02-01T23:59:59.000Z

66

Material-modeling and structural-mechanics aspects  

E-Print Network [OSTI]

Material-modeling and structural-mechanics aspects of the traumatic brain injury problem M for causing traumatic brain injury. Design/methodology/approach ­ Two levels of blast peak overpressure were computational investigation of impact on a human skull/brain assembly. Keywords Brain, Injuries, Modeling

Grujicic, Mica

67

A mechanical approach to mean field spin models  

E-Print Network [OSTI]

Inspired by the bridge pioneered by Guerra among statistical mechanics on lattice and analytical mechanics on 1+1 continuous Euclidean space-time, we built a self-consistent method to solve for the thermodynamics of mean-field models defined on lattice, whose order parameters self average. We show the whole procedure by analyzing in full details the simplest test case, namely the Curie-Weiss model. Further we report some applications also to models whose order parameters do not self-average, by using the Sherrington-Kirkpatrick spin glass as a guide.

Giuseppe Genovese; Adriano Barra

2009-05-07T23:59:59.000Z

68

Constitutive modeling of creep of single crystal superalloys  

E-Print Network [OSTI]

In this work, a constitutive theory is developed, within the context of continuum mechanics, to describe the creep deformation of single crystal superalloys. The con- stitutive model that is developed here is based on the fact that as bodies deform...

Prasad, Sharat Chand

2006-10-30T23:59:59.000Z

69

A mechanical model of early salt dome growth  

E-Print Network [OSTI]

A MECHANICAL MODEL OF EARLY SALT DOME GROWTH A Thesis by FRANK ALBERT IRWIN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1988... Major Subject: Geology A MECHANICAL MODEL OF EARLY SALT DOME GROWTH A Thesis by FRANK ALBERT IRWIN Approved as to style and content by: aymond C. Fletcher (Chair of Committee) John H. Spang (Member) Wi tamR. B ant (Mem ) John H. Sp g (Head...

Irwin, Frank Albert

2012-06-07T23:59:59.000Z

70

Thermal And Thermo-Mechanical Modelling of Polymer Overmoulded Electronics  

E-Print Network [OSTI]

electronics for use in the demanding automotive environment. A two shot moulding technology will protect of electronics within polymer materials is of great interest to the automotive industry as a means to protectThermal And Thermo-Mechanical Modelling of Polymer Overmoulded Electronics F. Sarvar1 , D. C

Paris-Sud XI, Université de

71

Modelling the mechanical behaviour of pharmaceutical powders during compaction  

E-Print Network [OSTI]

are made of dry powder through a powder compaction process. In the pharmaceutical industry, billionsModelling the mechanical behaviour of pharmaceutical powders during compaction C.-Y. Wua,T, O.M. Ruddyb , A.C. Benthamb , B.C. Hancockc , S.M. Besta , J.A. Elliotta a Pfizer Institute for Pharmaceutical

Elliott, James

72

Charge-Dependent Cavity Radii for an Accurate Dielectric Continuum Model of Solvation with Emphasis on Ions: Aqueous Solutes with Oxo, Hydroxo, Amino, Methyl, Chloro, Bromo and Fluoro Functionalities  

SciTech Connect (OSTI)

Dielectric continuum solvation models are widely used because they are a computationally efficacious way to simulate equilibrium properties of solutes. With advances that allow for molecular-shaped cavities, they have reached a high level of accuracy, in particular for neutral solutes. However, benchmark tests show that existing schemes for defining cavities are unable to consistently predict accurately the effects of solvation on ions, especially anions. This work involves the further development of a protocol put forth earlier for defining the cavities of aqueous solutes, with resulting advances that are most striking for anions. Molecular cavities are defined as interlocked spheres around atoms or groups of atoms in the solute, but the sphere radii are determined by simple empirically-based expressions involving the effective atomic charges of the solute atoms (derived from molecular electrostatic potential) and base radii. Both of these terms are optimized for the different types of atoms or functional groups in a training set of neutral and charged solutes. Parameters in these expressions for radii were fitted by minimizing residuals between calculated and measured standard free energies of solvation (?Gs*), weighted by the uncertainty in the measured value. The calculations were performed using density functional theory with the B3LYP functional and the 6-311+G** basis set and the COnductor-like Screening MOdel (COSMO). The optimized radii definitions reproduce ?Gs* of neutral solutes and singly-charged ions in the training set to within experimental uncertainty and, more importantly, accurately predict ?Gs* of compounds outside the training set, in particular anions. Inherent to this approach, the cavity definitions reflect the strength of specific solute-water interactions. We surmise that this feature underlies the success of the model, referred to as the CD-COSMO model for Charge-Dependent (also Camaioni-Dupuis) COSMO model. These findings offer encouragement that we can keep extending this scheme to other functional groups and obtain better accuracy in using continuum solvation models to predict equilibrium properties of aqueous ionic solutes. The approach is illustrated for a number of test cases, including the determination of acidities of an amine base and a study of the tautomerization equilibrium of a zwitterionic molecule (glycine). The approach is also extended to calculating solvation energies of transition states toward a full characterization of reaction pathways in aqueous phase, here in SN2 exchange reactions. The calculated reactions barriers in aqueous solution are in excellent agreement with experimental values. 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.

Ginovska, Bojana; Camaioni, Donald M.; Dupuis, Michel; Schwerdtfeger, Christine A.; Gilcrease, Quinn

2008-10-23T23:59:59.000Z

73

Mechanical modeling of porous oxide fuel pellet A Test Problem  

SciTech Connect (OSTI)

A poro-elasto-plastic material model has been developed to capture the response of oxide fuels inside the nuclear reactors under operating conditions. Behavior of the oxide fuel and variation in void volume fraction under mechanical loading as predicted by the developed model has been reported in this article. The significant effect of void volume fraction on the overall stress distribution of the fuel pellet has also been described. An important oxide fuel issue that can have significant impact on the fuel performance is the mechanical response of oxide fuel pellet and clad system. Specifically, modeling the thermo-mechanical response of the fuel pellet in terms of its thermal expansion, mechanical deformation, swelling due to void formation and evolution, and the eventual contact of the fuel with the clad is of significant interest in understanding the fuel-clad mechanical interaction (FCMI). These phenomena are nonlinear and coupled since reduction in the fuel-clad gap affects thermal conductivity of the gap, which in turn affects temperature distribution within the fuel and the material properties of the fuel. Consequently, in order to accurately capture fuel-clad gap closure, we need to account for fuel swelling due to generation, retention, and evolution of fission gas in addition to the usual thermal expansion and mechanical deformation. Both fuel chemistry and microstructure also have a significant effect on the nucleation and growth of fission gas bubbles. Fuel-clad gap closure leading to eventual contact of the fuel with the clad introduces significant stresses in the clad, which makes thermo-mechanical response of the clad even more relevant. The overall aim of this test problem is to incorporate the above features in order to accurately capture fuel-clad mechanical interaction. Because of the complex nature of the problem, a series of test problems with increasing multi-physics coupling features, modeling accuracy, and complexity are defined with the objective of accurate simulation of fuel-clad mechanical interaction subjected to a wide-range of thermomechanical stimuli.

Nukala, Phani K [ORNL; Barai, Pallab [ORNL; Simunovic, Srdjan [ORNL; Ott, Larry J [ORNL

2009-10-01T23:59:59.000Z

74

NREL: Continuum Magazine Home Page  

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

Deliberate Science Deliberate Science Issue 2 Print Version Share this resource Continuum Magazine Dan Says Reinventing Material Science Reinventing Material Science It's not often that scientists set out to reinvent an entire field of study, but it's happening now. Better Biofuels through Computational Analysis Better Biofuels through Computational Analysis Developing and applying a powerful arsenal of computational tools for producing biofuels. Supercomputing Drives Innovation Supercomputing Drives Innovation Researchers are finding new ways of tackling our nation's energy challenges. Carbon Nanotubes for Batteries Carbon Nanotubes for Batteries Groundbreaking battery technology holds potential to revolutionize powering vehicles. Rewiring Algae's Catalytic Circuits Rewiring Algae's Catalytic Circuits

75

Rabi-split states broadened by a continuum  

SciTech Connect (OSTI)

In this work we theoretically investigate a ?-like three-level system. Our model consists of a onedimensional quantum well with a nearby continuum. The ? level structure is formed by the ground state (a valence band state) and two excited states (both in conduction band), one being a localized and the other a quasi-bound state which is interacting with the continuum. An infrared (IR) field is used to drive the excited states into dressed states creating Autler-Townes doublets. We solve the semiconductor Bloch equation, in real space and in time domain, to follow the interband optical excitation dynamics. The optical absorption and the photocurrent spectra are calculated for different potential barriers separating the well and the continuum. We show how this affects the Autler-Townes doublets since this is a possible way of changing the relationship between the IR Rabi frequency and the dephasing rates.

Maialle, M. Z.; Degani, M. H. [Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira-SP (Brazil); Madureira, J. R. [Universidade Federal de Uberlândia, Utuiutaba-MG (Brazil)

2013-12-04T23:59:59.000Z

76

Mechanical properties and modeling of seal-forming lithologies  

SciTech Connect (OSTI)

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.

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

1993-01-01T23:59:59.000Z

77

Bioinspired, mechanical, deterministic fractal model for hierarchical suture joints  

Science Journals Connector (OSTI)

Many biological systems possess hierarchical and fractal-like interfaces and joint structures that bear and transmit loads, absorb energy, and accommodate growth, respiration, and/or locomotion. In this paper, an elastic deterministic fractal composite mechanical model was formulated to quantitatively investigate the role of structural hierarchy on the stiffness, strength, and failure of suture joints. From this model, it was revealed that the number of hierarchies (N) can be used to tailor and to amplify mechanical properties nonlinearly and with high sensitivity over a wide range of values (orders of magnitude) for a given volume and weight. Additionally, increasing hierarchy was found to result in mechanical interlocking of higher-order teeth, which creates additional load resistance capability, thereby preventing catastrophic failure in major teeth and providing flaw tolerance. Hence, this paper shows that the diversity of hierarchical and fractal-like interfaces and joints found in nature have definitive functional consequences and is an effective geometric-structural strategy to achieve different properties with limited material options in nature when other structural geometries and parameters are biologically challenging or inaccessible. This paper also indicates the use of hierarchy as a design strategy to increase design space and provides predictive capabilities to guide the mechanical design of synthetic flaw-tolerant bioinspired interfaces and joints.

Yaning Li; Christine Ortiz; Mary C. Boyce

2012-03-01T23:59:59.000Z

78

Mechanical properties and modeling of seal-forming lithologies  

SciTech Connect (OSTI)

Both rocksalt and shale lithologies are actively deformed in response to gravitational loads associated with deposition, and both form effective seals to petroleum and natural gas. Thus, the shapes of seal-forming units, and the nature of fractures and faults that may breach them depend upon either the mechanical properties of salt or those of shale, and the loading histories to which they have been subjected. The objectives of this research include the determination of the mechanical properties under controlled conditions of well-characterized shales, and the numerical modeling of rocksalt (and eventually shale) formations using laboratory-based rheologies. Progress has been made towards these goals over this project period, both in our experimental program on shale deformation and model development for the growth of salt diapirs. The mechanical anisotropy of an illite-bearing shale from Louisiana has been determined and related to the preferred orientation and distribution of clays. Its strength in the absence of pore fluids has been determined at confining pressures of up to 250 MPa and at high pressure we have investigated the effects of deformation rate and temperature. A numerical finite difference code has been developed to solve the incompressible Navier-Stokes equations and validated using a two- layer linear viscous model for which analytic solutions are available. Although the code has only been validated for the linear viscous case, it is capable of solving for highly nonlinear constitutive laws as well as solving for arbitrary interfaces between the salt and overburden.

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

1992-04-01T23:59:59.000Z

79

Microstructurally-based constitutive models of cytoskeletal networks for simulation of the biomechanical response of biological cells  

E-Print Network [OSTI]

The elastic and viscoelastic stress-strain behavior of cytoskeletal networks, important to many cellular functions, is modeled via a microstructurally-informed continuum mechanics approach. The force-extension behavior of ...

Palmer, Jeffrey Shane

2008-01-01T23:59:59.000Z

80

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

SciTech Connect (OSTI)

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.

Dryer, F.L.; Yetter, R.A. [Princeton Univ., NJ (United States)

1993-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Modeling the Q-cycle mechanism of transmembrane energy conversion  

E-Print Network [OSTI]

The Q-cycle mechanism plays an important role in the conversion of the redox energy into the energy of the proton electrochemical gradient across the biomembrane. The bifurcated electron transfer reaction, which is built into this mechanism, recycles one electron, thus, allowing to translocate two protons per one electron moving to the high-potential redox chain. We study a kinetic model of the Q-cycle mechanism in an artificial system which mimics the bf complex of plants and cyanobacteria in the regime of ferredoxin-dependent cyclic electron flow. Using methods of condensed matter physics, we derive a set of master equations and describe a time sequence of electron and proton transfer reactions in the complex. We find energetic conditions when the bifurcation of the electron pathways at the positive side of the membrane occurs naturally, without any additional gates. For reasonable parameter values, we show that this system is able to translocate more than 1.8 protons, on average, per one electron, with a thermodynamic efficiency of the order of 32% or higher.

Anatoly Yu. Smirnov; Franco Nori

2011-06-29T23:59:59.000Z

82

A continuum theory of thermoelectric bodies and effective properties of thermoelectric composites  

E-Print Network [OSTI]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3 A constitutive model for thermoelectric materials . . . . . . . . . . . . . . . . . . . . 6 2 composites. 1 Introduction Thermoelectric (TE) materials directly convert heat into electric energyA continuum theory of thermoelectric bodies and effective properties of thermoelectric composites

Liu, Liping

83

N + 1 dimensional quantum mechanical model for a closed universe  

E-Print Network [OSTI]

A quantum mechanical model for an N + 1 dimensional universe arising from a quantum fluctuation is outlined. (3 + 1) dimensions are a closed infinitely-expanding universe and the remaining N - 3 dimensions are compact. The (3 + 1) non-compact dimensions are modeled by quantizing a canonical Hamiltonian description of a homogeneous isotropic universe. It is assumed gravity and the strong-electro-weak (SEW) forces had equal strength in the initial state. Inflation occurred when the compact N -3 dimensional space collapsed after a quantum transition from the initial state of the univers, during its evolution to the present state where gravity is much weaker than the SEW force. The model suggests the universe has no singularities and the large size of our present universe is determined by the relative strength of gravity and the SEW force today. A small cosmological constant, resulting from the zero point energy of the scalar field corresponding to the compact dimensions, makes the model universe expand forever.

T. R. Mongan

1999-02-10T23:59:59.000Z

84

JOINT ESTIMATION OF CARDIAC KINEMATICS AND MATERIAL PARAMETERS FROM NOISY IMAGING DATA AND UNCERTAIN MECHANICAL MODEL  

E-Print Network [OSTI]

AND UNCERTAIN MECHANICAL MODEL Huafeng Liu, Edward W.B. Lo, and Pengcheng Shi Biomedical Research Laboratory

Shi, Pengcheng

85

Thermo-mechanical modeling of plasterboard lined partition submitted to fire load.  

E-Print Network [OSTI]

Thermo-mechanical modeling of plasterboard lined partition submitted to fire load. Authors: S.heck@cstb.fr Abstract: An important problem is the development of a thermo-mechanical model of plasterboard lined and the experimental validation of a deterministic and a probabilistic thermo-mechanical model of cardboard

Paris-Sud XI, Université de

86

A unified continuum representation of post-seismic relaxation mechanisms: semi-analytic models of afterslip, poroelastic rebound and viscoelastic flow  

Science Journals Connector (OSTI)

......conjunction with our body-force method. The Green's function...Abramowitz M. , Stegun I., 1972. Handbook of Mathematical Functions with...Cheng A.H.-D., 1993. Fundamentals of poroelasticity, inComprehensive...Fluid mass sources and point forces in linear elastic diffusive......

Sylvain Barbot; Yuri Fialko

2010-09-01T23:59:59.000Z

87

Microstructural viscoplastic continuum model for asphalt concrete  

E-Print Network [OSTI]

(1984)?????????.? 18 Sides et al. (1985)????????????????? 19 Desai and Zhang (1987)??????????????.. 19 Sousa et al. (1993)????????????????... 20 Strategic Highway Research Program (SHRP) Report A-357 (Lytton et al. 1993)????????????????.. 22 Florea... (1994a, 1994b)???????????????. 23 Sousa and Weissman (1994)????????????... 24 Scarpas et al. (1997a)???????????????.. 25 Lu and Wright (1998)???????????????. 27 viii CHAPTER Page Seibi et al. (2001)????????????????? 27 Huang et al. (2002...

Tashman, Laith

2004-09-30T23:59:59.000Z

88

Mechanical tests for validation of seismic isolation elastomer constitutive models  

SciTech Connect (OSTI)

High damping laminated elastomeric bearings are becoming the preferred device for seismic isolation of large buildings and structures, such as nuclear power plants. The key component of these bearings is a filled natural rubber elastomer. This material exhibits nonlinear behavior within the normal design range. The material damping cannot be classified as either viscous or hysteritic, but it seems to fall somewhere in between. This paper describes a series of tests that can be used to characterize the mechanical response of these elastomers. The tests are designed to determine the behavior of the elastomer in the time scale of the earthquake, which is typically from 30 to 60 seconds. The test results provide data for use in determining the material parameters associated with nonlinear constitutive models. 4 refs.

Kulak, R.F.; Hughes, T.H.

1992-01-01T23:59:59.000Z

89

Mechanical tests for validation of seismic isolation elastomer constitutive models  

SciTech Connect (OSTI)

High damping laminated elastomeric bearings are becoming the preferred device for seismic isolation of large buildings and structures, such as nuclear power plants. The key component of these bearings is a filled natural rubber elastomer. This material exhibits nonlinear behavior within the normal design range. The material damping cannot be classified as either viscous or hysteritic, but it seems to fall somewhere in between. This paper describes a series of tests that can be used to characterize the mechanical response of these elastomers. The tests are designed to determine the behavior of the elastomer in the time scale of the earthquake, which is typically from 30 to 60 seconds. The test results provide data for use in determining the material parameters associated with nonlinear constitutive models. 4 refs.

Kulak, R.F.; Hughes, T.H.

1992-05-01T23:59:59.000Z

90

Journal of the Mechanics and Physics of Solids 52 (2004) 24032430  

E-Print Network [OSTI]

.elsevier.com/locate/jmps A quantum-mechanically informed continuum model of hydrogen embrittlement S. Serebrinskya, E.A. Carterb, M 4 February 2004; accepted 13 February 2004 Abstract We present a model of hydrogen embrittlement for hydrogen-assisted cracking. ? 2004 Elsevier Ltd. All rights reserved. Keywords: Hydrogen embrittlement

Serebrinsky, Santiago A.

91

Relativistic viscoelastic fluid mechanics  

SciTech Connect (OSTI)

A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.

Fukuma, Masafumi; Sakatani, Yuho [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

2011-08-15T23:59:59.000Z

92

NUMERICAL MODELLING OF AUTOGENOUS HEALING AND RECOVERY OF MECHANICAL PROPERTIES IN ULTRA-HIGH  

E-Print Network [OSTI]

, hydro-chemo- mechanical coupling ABSTRACT Cracks, caused by shrinkage or external loading, reduce. In this study, a hydro-chemo-mechanical model was developed to simulate autogenous healing by further hydration into water was modelled based on micro-mechanical observations. The diffusion process has been simulated

Boyer, Edmond

93

Port-based modeling and simulation of mechanical systems with rigid and flexible links  

Science Journals Connector (OSTI)

In this paper, a systematic procedure for the definition of the dynamical model in port-Hamiltonian form of mechanical systems is presented as the result of the power-conserving interconnection of a set of basic components (rigid bodies, flexible links, ... Keywords: flexible mechanisms, mechanisms dynamics, modeling, port-Hamiltonian systems, simulation

Alessandro Macchelli; Claudio Melchiorri; Stefano Stramigioli

2009-10-01T23:59:59.000Z

94

Design and modeling of carbon nanotube-based compliant mechanisms  

E-Print Network [OSTI]

The objective of this research is to generate the knowledge required to adapt macro- and microscale compliant mechanism theory to design carbon nanotube-based nano-scale compliant mechanisms. Molecular simulations of a ...

DiBiasio, Christopher M. (Christopher Michael)

2007-01-01T23:59:59.000Z

95

Gas-Kinetic Scheme for Continuum and Near-Continuum Hypersonic Flows  

E-Print Network [OSTI]

Gas-Kinetic Scheme for Continuum and Near-Continuum Hypersonic Flows Wei Liao and Li-Shi Luo Old. The gas-kinetic schemes are validated with simulations of the hypersonic flow past a hollow flare at Mach and simulation of complex hypersonic flows become very challenging for computa- tional fluid dynamics (CFD) [1

Xu, Kun

96

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...

97

Mechanisms of thiophene hydrodesulfurization on model molybdenum catalysts  

SciTech Connect (OSTI)

Hydrodesulfurization (HDS) activities and selectivities were measured for thiophene, tetrahydrothiophene (THT), and 1-butanethiol on silica-supported molybdenum catalysts at a pressure of 1 atm and temperatures ranging from 530 to 795 K. The model catalysts, which were previously characterized, feature isolated molybdenum atoms in the +2, +4, and +6 oxidation states and molybdenum dimers with each molybdenum atom in the +4 oxidation state. Silica-supported MoS{sub 2} was used for reference. Activities for thiophene and THT HDS correlate with oxidation state. Mo(II) is most active among dispersed catalysts. 1-Butanethiol activities were much larger than thiophene or THT activities and were roughly equal on all dispersed catalysts. Apparent activation energies of 43.4 and 48.5 kJ/mol were determined for thiophene HDS on Mo(II) and MoS{sub 2}/SiO{sub 2}, respectively. Dihydrothiophene, THT and 1-butanethiol were formed in thiophene HDS over Mo(II) and MoS{sub 2}/SiO{sub 2}. The major products of thiophene and THT HDS were 1-butene, 2-butene, and n-butene. Butadiene, i-butane, i-butene, methane, ethane, ethene, propane, and propene were formed in small amounts. Butadiene is thought to be the initial product of thiophene and THT desulfurization and undergoes subsequent hydrogenation and isomerization to yield the observed products. A common mechanism for HDS of thiophene and THT with 2,5-DHT as an intermediate is discussed.

Sullivan, D.L.; Ekerdt, J.G. [Univ. of Texas, Austin, TX (United States). Dept. of Chemical Engineering] [Univ. of Texas, Austin, TX (United States). Dept. of Chemical Engineering

1998-08-15T23:59:59.000Z

98

Current-based 4D shape analysis for the mechanical personalization of heart models  

E-Print Network [OSTI]

Current-based 4D shape analysis for the mechanical personalization of heart models Lo¨ic Le Folgoc1. Abstract. Patient-specific models of the heart may lead to better understanding of cardiovascular diseases-mechanical model of the heart, from the kinematics of the endo- and epicardium, is presented in this paper. We use

Paris-Sud XI, Université de

99

Computer Modelling and Simulations of Enzymes and their Mechanisms .  

E-Print Network [OSTI]

??Although the tremendous catalytic power of enzymes is widely recognized, their exact mechanisms of action are still a source of debate. In order to elucidate… (more)

Alonso, Hernan

2010-01-01T23:59:59.000Z

100

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

Office of Scientific and Technical Information (OSTI)

system and contributes to the EGS, both mechanically (e.g., cooling shrinkage and fracture shear reactivation) and chemically (e.g., dissolution). * To demonstrate the...

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

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

Broader source: Energy.gov [DOE]

Development of Advanced Thermal-Hydrological-Mechanical-Chemical (THMC) Modeling Capabilities for Enhanced Geothermal Systems presentation at the April 2013 peer review meeting held in Denver, Colorado.

102

Mechanisms and modeling of single-event upset  

SciTech Connect (OSTI)

The basic mechanisms of single-event upset are reviewed, including charge collection in silicon junctions and transistors, and properties of single-event upset in CMOS static random access memory (SRAM) cells. The mechanisms are illustrated through the use of three-dimensional device and circuit simulations. Technology trends and implications for commercial devices are discussed.

Dodd, Paul E.

1998-10-12T23:59:59.000Z

103

Thermo-mechanical model of a cardboard-plaster-cardboard composite  

E-Print Network [OSTI]

Thermo-mechanical model of a cardboard-plaster-cardboard composite plate submitted to fire load Mechanics laboratory, Marne-la-Vall´ee University, France Abstract Generally, the standard rules require with experiments in order to predict thermo- mechanical overall partition behaviour. This research is organized

Paris-Sud XI, Université de

104

Neutrino mass mechanisms in 3-3-1 models: A short review  

E-Print Network [OSTI]

In this paper we review some mechanisms that provide light neutrinos in the framework of 3-3-1 gauge models without exotic leptons. In regard to the minimal 3-3-1 model, we call the attention to the fact that the perturbative regime of the model goes until 5 TeV. This requires alternative mechanisms in order to generate light neutrinos. In this review we discuss two mechanisms capable of generating light neutrinos in the framework of the minimal 3-3-1 model. In regard to the 3-3-1 model with right-handed neutrinos, we call the attention to the fact that in it mechanisms that generate light left-handed neutrinos also generate light right-handed neutrinos. Finally, we call the attention to the fact that the 3-3-1 model with right-handed neutrinos accommodate naturally the inverse seesaw mechanism.

Pires, C A de S

2014-01-01T23:59:59.000Z

105

Modeling of chemical mechanical polishing for shallow trench isolation  

E-Print Network [OSTI]

This thesis presents the nonlinear analysis, design, fabrication, and testing of an axial-gap magnetic induction micro machine, which is a two-phase planar motor in which the rotor is suspended above the stator via mechanical ...

Lee, Brian, 1975-

2002-01-01T23:59:59.000Z

106

Molecular-To-Continuum Fracture Analysis of Thermosetting Polymer/Solid Interfaces  

SciTech Connect (OSTI)

This report focuses on the relationship between the fundamental interactions acting across an interface and macroscopic engineering observable such as fracture toughness or fracture stress. The work encompasses experiment, theory, and simulation. The model experimental system is epoxy on polished silicon. The interfacial interactions between the substrate and the adhesive are varied continuously using self-assembling monolayer. Fracture is studied in two specimen geometries: a napkin-ring torsion geometry and a double cantilevered beam specimen. Analysis and modeling involves molecular dynamics simulations and continuum mechanics calculations. Further insight is gained from analysis of measurements in the literature of direct force measurements for various fundamental interactions. In the napkin-ring test, the data indicate a nonlinear relationship between interface strength and fracture stress. In particular, there is an abrupt transition in fracture stress which corresponds to an adhesive-to-cohesive transition. Such nonlinearity is not present in the MD simulations on the tens-of-nanometer scale, which suggests that the nonlinearity comes from bulk material deformation occurring on much larger length scales. We postulate that the transition occurs when the interface strength becomes comparable to the yield stress of the material. This postulate is supported by variation observed in the fracture stress curve with test temperature. Detailed modeling of the stress within the sample has not yet been attempted. In the DCB test, the relationship between interface strength and fracture toughness is also nonlinear, but the fracture mechanisms are quite different. The fracture does not transition from adhesive to cohesive, but remains adhesive over the entire range of interface strength. This specimen is modeled quantitatively by combining (i) continuum calculations relating fracture toughness to the stress at 90 {angstrom} from the crack tip, and (ii) a relationship from molecular simulations between fracture stress on a {approx} 90 {angstrom} scale and the fraction of surface sites which chemically bond. The resulting relationship between G{sub c} and fraction of bonding sites is then compared to the experimental data. This first order model captures the nonlinearity in the experimentally-determined relationship. A much more extensive comparison is needed (calculations extending to higher G{sub c} values, experimental data extending to lower G{sub c} values) to guide further model development.

KENT,MICHAEL S.; REEDY JR.,EARL DAVID; STEVENS,MARK J.

2000-01-01T23:59:59.000Z

107

Grid sensitivity in low Reynolds number hypersonic continuum flows  

SciTech Connect (OSTI)

A computational scheme is presented to solve the unsteady Navier-Stokes equations over a blunt body at high altitude, high Mach number atmospheric reentry flow conditions. This continuum approach is directed to low Reynolds/low density hypersonic flows by accounting for non-zero bulk viscosity effects in near frozen flow conditions. A significant difference from previous studies is the inclusion of the capability to model non-zero bulk viscosity effects. The grid definition for these low Reynolds number, viscous dominated flow fields is especially important in terms of numerical stability and accurate heat transfer solutions. 11 refs., 15 figs.

Rutledge, W.H. (Sandia National Labs., Albuquerque, NM (USA)); Hoffmann, K.A. (Wichita State Univ., KS (USA). Dept. of Aerospace Engineering)

1991-01-01T23:59:59.000Z

108

CoEvolutionary Incremental Modelling of Robotic Cognitive Mechanisms  

E-Print Network [OSTI]

, trahania}@ics.forth.gr Abstract. Recently, brain models attempt to support cognitive abili- ties work introduces a novel com- putational framework for incremental brain modelling, which aims properly formulated neural agents to represent brain areas. A collaborative coevolutionary method

Trahanias, Panos

109

The Hygrocyst–a Stability Phenomenon in Continuum Mechanics  

Science Journals Connector (OSTI)

... Fig. 1. Hygrocysts in a rotating circular tube. SAE-30 motor oil occupies 70 per cent of tube volume. Rotational speed is 4 ... 1 presents the new secondary flow pattern in a rotating sealed circular tube containing an SAE-30 motor oil. The volume of the fluid is 70 per cent of the ...

ROBERT THEODORE BALMER

1970-08-08T23:59:59.000Z

110

Continuum mechanics beyond the second law of thermodynamics  

Science Journals Connector (OSTI)

...corresponds to situations in statistical physics allowing violations of the second law...Diggle, M Fuentes, and P Guttorp. 2010 Handbook of spatial statistics. Boca Raton, FL...acceleration waves in solids. In Encyclopedia of physics, vol. VI a/3 (eds S Flugge and C...

2014-01-01T23:59:59.000Z

111

A Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir  

Open Energy Info (EERE)

Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir Evaluation Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir Evaluation Details Activities (0) Areas (0) Regions (0) Abstract: A two-dimensional numerical model of coupled fluid flow, heat transfer and rock mechanics in naturally fractured rock is developed. The model is applicable to assessments of hot dry rock (HDR) geothermal reservoir characterisation experiments, and to the study of hydraulic stimulations and the heat extraction potential of HDR reservoirs. Modelling assumptions are based on the characteristics of the experimental HDR reservoir in the Carnmenellis granite in Cornwall, S. W. England. In

112

A Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei  

Open Energy Info (EERE)

Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Caldera Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Caldera Details Activities (0) Areas (0) Regions (0) Abstract: We present here a consistent model, which explains the mechanisms of unrest phenomena at Campi Flegrei (Italy), both at short-term (years) and at secular scales. The model consists basically of two effects: the first one is related to the elastic response of the shallow crust to increasing pressure within a shallow magma chamber; the second involves the fluid-dynamics of shallow aquifers in response to increasing pressure and/or temperature at depth. The most important roles in the proposed model

113

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

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

of mechanistic crack growth and grain contact models for chemically induced subcritical crack growth and pressure solution, with porosity-permeability changes * Conduct...

114

Coupled Thermal-Hydrological-Mechanical-Chemical Model and Experiments...  

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

of mechanistic crack growth and grain contact models for chemically induced subcritical crack growth and pressure solution, with porosity-permeability changes * Conduct...

115

Connecting the Molecular and the Continuum Scales  

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

Connecting the Connecting the Molecular and the Continuum Scales Connecting the Molecular and the Continuum Scales Key Challenges: A molecular-scale understanding of structure and surface chemistry of clay mineral surface nanoparticles. Why it Matters: With a ubiquitous presence in natural materials and strong surface reactions, nanoparticles figure importantly in a broad range of phenomena, from climate change to contaminant remediation. Accomplishments: Used molecular dynamics (MD) simulations to determine molecular-scale diffusion coefficients of water tracers and representative cations (Na+,Cs+,Sr2+) in Smectite and found a simple way to accurately relate this to bulk, pore-scale diffusion. The result is that a remarkably simple expression relates Dinterlayer to the pore-scale

116

2.4 CONTINUUM MECHANICS (SOLIDS) In this introduction to continuum mechanics we consider the basic equations describing the physical  

E-Print Network [OSTI]

the basic equations describing the physical e#ects created by external forces acting upon solids and fluids

California at Santa Cruz, University of

117

Cosmology with SKA Radio Continuum Surveys  

E-Print Network [OSTI]

Radio continuum surveys have, in the past, been of restricted use in cosmology. Most studies have concentrated on cross-correlations with the cosmic microwave background to detect the integrated Sachs-Wolfe effect, due to the large sky areas that can be surveyed. As we move into the SKA era, radio continuum surveys will have sufficient source density and sky area to play a major role in cosmology on the largest scales. In this chapter we summarise the experiments that can be carried out with the SKA as it is built up through the coming decade. We show that the SKA can play a unique role in constraining the non-Gaussianity parameter to \\sigma(f_NL) ~ 1, and provide a unique handle on the systematics that inhibit weak lensing surveys. The SKA will also provide the necessary data to test the isotropy of the Universe at redshifts of order unity and thus evaluate the robustness of the cosmological principle.Thus, SKA continuum surveys will turn radio observations into a central probe of cosmological research in th...

Jarvis, Matt J; Blake, Chris; Brown, Michael L; Lindsay, Sam N; Raccanelli, Alvise; Santos, Mario; Schwarz, Dominik

2015-01-01T23:59:59.000Z

118

Mathematical equations as executable models of mechanical systems  

Science Journals Connector (OSTI)

Cyber-physical systems comprise digital components that directly interact with a physical environment. Specifying the behavior desired of such systems requires analytical modeling of physical phenomena. Similarly, testing them requires simulation ...

Yun Zhu; Edwin Westbrook; Jun Inoue; Alexandre Chapoutot; Cherif Salama; Marisa Peralta; Travis Martin; Walid Taha; Marcia O'Malley; Robert Cartwright; Aaron Ames; Raktim Bhattacharya

2010-04-01T23:59:59.000Z

119

Notes 01. Modeling of mechanical (lumped parameter) elements  

E-Print Network [OSTI]

are given by the equations [][ ][] dtPE,xDxP t 0 vv T v ? == #0;#5;#0;#5; (3) where n,1j,ij,i }d{]D[ = = is a matrix of constant damping coefficients. The work performed by external forces is given by, [][ ] FxdW T ? = (4) MEEN 617..., Appendix C: Derivation of EOMs for MDOF system. L San Andr?s (2008) C-2 The principle of conservation of mechanical energy establishes that for any instant of time, 00v TV E W T V++ = + + (5) where [ ] [ ][ ] [ ] [ ][ ] 11 00 000 022 , TT Tx...

San Andres, Luis

2008-01-01T23:59:59.000Z

120

Lattice Boltzmann model for the simulation of multicomponent mixtures  

Science Journals Connector (OSTI)

A lattice Boltzmann (LB) model for the simulation of realistic multicomponent mixtures is constructed. In the hydrodynamic limit, the LB model recovers the equations of continuum mechanics within the mixture-averaged diffusion approximation. The present implementation can be used to simulate realistic mixtures with arbitrary Schmidt numbers and molecular masses of the species. The model is applied to the mixing of two opposed jets of different concentrations and the results are in excellent agreement with a continuum model. An application to the simulation of mixtures in microflows is also presented. Results compare well with existing kinetic theory predictions of the slip coefficient for mixtures in a Couette flow.

S. Arcidiacono; I. V. Karlin; J. Mantzaras; C. E. Frouzakis

2007-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Composite materials non-linear modelling for long fibre-reinforced laminates  

Science Journals Connector (OSTI)

An innovative computational methodology is proposed for modelling the material non-linear mechanical behaviour of FRP structures. To model a single unidirectional composite lamina, a serial-parallel (SP) continuum approach has been developed assuming ... Keywords: Composite failure, FEM, FRP, Long fibre laminates, Non-linear modelling

Fernando Rastellini; Sergio Oller; Omar Salomón; Eugenio Oñate

2008-05-01T23:59:59.000Z

122

BYU PHYS 731 Statistical Mechanics Chapters 8 and 9: Sethna Professor Manuel Berrondo Ising Model  

E-Print Network [OSTI]

BYU PHYS 731 Statistical Mechanics Chapters 8 and 9: Sethna Professor Manuel Berrondo Ising Model interaction) -External eld H H = -J ij sisj - H i si Ising Hamiltonian Binary alloy type A, type B (Cu-Zn) NA - EABNAB Equivalent to Ising model J = 1 4 (EAA + EBB - 2EAB) and H = EAA - EBB Lattice gas model good

Hart, Gus

123

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

SciTech Connect (OSTI)

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.

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

2006-09-28T23:59:59.000Z

124

A Producer-Consumer Model with Stoichiometric Elimination Mechanisms  

E-Print Network [OSTI]

, and the efficiency of the consumer's conversion of producer biomass to its own biomass. The elimination model we, or equivalently, the stoichiometric ratio of nutrient to biomass, as well as the biomass, is of interest on the flow of a single currency, such as energy stored in carbon compounds or biomass. This point of view

Peckham, Bruce B.

125

Carbon Nanotube Mats and Fibers with Irradiation-Improved Mechanical Characteristics: ATheoretical Model  

E-Print Network [OSTI]

Carbon Nanotube Mats and Fibers with Irradiation-Improved Mechanical Characteristics: ATheoretical model to calculate mechanical characteristics of macroscopic mats and fibers of single-walled carbon-flow technique [4]. The SWNT fibers, which in contrast to most ordinary carbon fibers could be strongly bent with

Krasheninnikov, Arkady V.

126

Application of the 3-D Hydro-Mechanical Model GEOFRAC in enhanced geothermal systems  

E-Print Network [OSTI]

GEOFRAC is a three-dimensional, geology-based, geometric-mechanical, hierarchical, stochastic model of natural rock fracture systems. The main characteristic of GEOFRAC is that it is based on statistical input representing ...

Vecchiarelli, Alessandra

2013-01-01T23:59:59.000Z

127

A Digital Model of a Dwell Mechanism for Alpha-Stirling Engine  

Science Journals Connector (OSTI)

The paper shows a digital model of a dwell mechanism dedicated to an ?-Stirling Engine. The low efficiency of an ?-Stirling Engine drives us to improve on its work...2]. The main way to achieve this is to improve...

N. M. Dehelean; V. Ciupe; E. C. Lovasz

2009-01-01T23:59:59.000Z

128

Mechanical Systems on an almost Kähler model of a Finsler Manifold  

E-Print Network [OSTI]

In this study, we present a new analogue of Euler-Lagrange and Hamilton equations on an almost K\\"ahler model of a Finsler manifold. Also, we give some corollories about the related mechanical systems and equations.

Mehmet Tekkoyun; O?uzhan Çelik

2012-11-06T23:59:59.000Z

129

Space time as a continuum with a point defect  

E-Print Network [OSTI]

In cosmology it has become usual to try and explain observational data, such as the temperature distribution of the cosmic microwave background or the accelerated expansion of the universe, introducing new entities as dark matter and dark energy. Here we describe a different approach treating space time as a continuum endowed with properties similar to the ones of ordinary material continua, such as internal viscosity and strain distributions originated by defects in the texture. A Lagrangian modelled on the one valid for simple dissipative phenomena in fluids is build and used for empty space time. The internal "viscosity" is shown to correspond to a four-vector field. Using the known symmetry of the universe, assuming the vector field to be divergence-less and solving the Euler-Lagrange equation we obtain directly inflation and a phase of accelerated expansion of space time. The vector field is shown to be connected with the displacement vector field induced by a point defect in a four-dimensional continuum...

Tartaglia, A

2006-01-01T23:59:59.000Z

130

Continuous-Discontinuous Model for Ductile Fracture  

SciTech Connect (OSTI)

In this contribution, a continuum-dicontinuum model for ductile failure is presented. The degradation of material properties trough deformation is described by Continuum Damage Mechanics in a non-local integral formulation to avoid mesh dependence. In the final stage of failure, the damaged zone is replaced by a cohesive macro crack and subsequent traction-free macro crack for a more realistic representation of the phenomenon. The inclusion of the discontinuity surfaces is performed by the XFEM and Level Set Method and avoids the spurious damage growth typical of this class of models.

Seabra, Mariana R. R.; Cesar de Sa, Jose M. A. [IDMEC- FEUP University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto (Portugal)

2010-06-15T23:59:59.000Z

131

Predictions from an Ising-like Statistical Mechanical Model on the Dynamic and Thermodynamic Effects of Protein Surface Electrostatics  

Science Journals Connector (OSTI)

Predictions from an Ising-like Statistical Mechanical Model on the Dynamic and Thermodynamic Effects of Protein Surface Electrostatics ...

Athi N. Naganathan

2012-10-05T23:59:59.000Z

132

Polymer, Vol. 46, no. 2, pp. 553-562 (2005) Modeling of the Mechanical Properties of Nanoparticle/Polymer Composites  

E-Print Network [OSTI]

and particles in the polymer. Several efforts have focused on the modeling of mechanical properties of nanoclay

Odegard, Gregory M.

133

Hybrid Particle-Continuum Methods for Nonequilibrium Gas and Plasma Flows  

SciTech Connect (OSTI)

Two different hybrid particle-continuum methods are described for simulation of nonequilibrium gas and plasma dynamics. The first technique, used for nonequilibrium hypersonic gas flows, uses either a continuum description or a particle method throughout a flow domain based on local conditions. This technique is successful in reproducing the results of full particle simulations at a small fraction of the cost. The second method uses a continuum model of the electrons combined with a particle description of the ions and atoms for simulating plasma jets. The physical accuracy of the method is assessed through comparisons with plasma plume measurements obtained in space. These examples illustrate that the complex physical phenomena associated with nonequilibrium conditions can be simulated with physical accuracy and numerical efficiency using such hybrid approaches.

Boyd, Iain D. [Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI (United States)

2011-05-20T23:59:59.000Z

134

Mechanical Engineering Department Seminar Series  

E-Print Network [OSTI]

Mechanical Engineering Department Seminar Series Rational Mechanics of Viral Shells: Is Continuum Theory a Stretch? William S. Klug Associate Professor, Mechanical & Aerospace Engineering, University-assembly. The capacity of these shells to respond structurally and mechanically to physical and chemical stimuli also

Eustice, Ryan

135

Coupled-channel continuum eigenchannel basis  

E-Print Network [OSTI]

The goal of this paper is to calculate bound, resonant and scattering states in the coupled-channel formalism without relying on the boundary conditions at large distances. The coupled-channel solution is expanded in eigenchannel bases i.e. in eigenfunctions of diagonal Hamiltonians. Each eigenchannel basis may include discrete and discretized continuum (real or complex energy) single particle states. The coupled-channel solutions are computed through diagonalization in these bases. The method is applied to a few two-channels problems. The exact bound spectrum of the Poeschl-Teller potential is well described by using a basis of real energy continuum states. For deuteron described by Reid potential, the experimental energy and the S and D contents of the wave function are reproduced in the asymptotic limit of the cutoff energy. For the Noro-Taylor potential resonant state energy is well reproduced by using the complex energy Berggren basis. It is found that the expansion of the coupled-channel wave function in these eigenchannel bases require less computational efforts than the use of any other basis. The solutions are stable and converge as the cutoff energy increases.

R. M. Id Betan

2013-11-18T23:59:59.000Z

136

Mechanical Degradation Onset of Polyethylene Oxide Used as a Hydrosoluble Model Polymer  

E-Print Network [OSTI]

Mechanical Degradation Onset of Polyethylene Oxide Used as a Hydrosoluble Model Polymer Degradation Onset of Polyethylene Oxide Used as a Hydrosoluble Model Polymer for Enhanced Oil Recovery and for both dilute and semi dilute polyethylene oxide aqueous solutions. It reveals that the exponent k

Boyer, Edmond

137

Probabilistic uncertainty modeling for thermo-mechanical analysis of plasterboard submitted to re load  

E-Print Network [OSTI]

with a probabilistic modeling of the thermo-mechanical behavior of cardboard-plaster-cardboard (CPC) multilayer plates resistance, cardboard-plaster-cardboard multilayer, un- certainties, probabilistic model, experiments presented in the last section. A plasterboard (cardboard-plaster-cardboard (CPC) multiplayer) gives

Paris-Sud XI, Université de

138

Nonintrusive 3D reconstruction of human bone models to simulate their bio-mechanical response  

Science Journals Connector (OSTI)

3D finite element models representing functional parts of the human skeletal system, have been repeatedly introduced over the last years, to simulate biomechanical response of anatomical characteristics or investigate surgical treatment. The reconstruction ... Keywords: 3D imaging, Bio-mechanical response, Computed tomography, FEM modeling

Tsouknidas Alexander; Lontos Antonis; Savvakis Savvas; Michailidis Nikolaos

2012-06-01T23:59:59.000Z

139

A non-isothermal PEM fuel cell model including two water transport mechanisms in the  

E-Print Network [OSTI]

A non-isothermal PEM fuel cell model including two water transport mechanisms in the membrane K Freiburg Germany A dynamic two-phase flow model for proton exchange mem- brane (PEM) fuel cells and the species concentrations. In order to describe the charge transport in the fuel cell the Poisson equations

Münster, Westfälische Wilhelms-Universität

140

Phenomenological modelling of viscoplasticity Mechanics of Materials Laboratory, Rensselaer Polytechnic Institute, Troy, NY 12180-3590,  

E-Print Network [OSTI]

331 Phenomenological modelling of viscoplasticity E. Krempl Mechanics of Materials Laboratory. - The essentials of phenomenological modeling of metal deformation behavior at small strain are introduced together interpreted from a materials science viewpoint are re-analyzed from a phenomenological point of view

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

NREL: Continuum Magazine - NREL and the Cleantech Industry  

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

strong links with the financial community, as well as other key stakeholders in the commercialization process. Video courtesy of ID8Nation Continuum Partnering: An Engine for...

142

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

SciTech Connect (OSTI)

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.

Eric Wachsman; Keith L. Duncan

2006-09-30T23:59:59.000Z

143

A Design, Simulation and Visualization Environment for Object-Oriented Mechanical and Multi-Domain Models in Modelica  

Science Journals Connector (OSTI)

The complexity of mechanical and multi-domain simulation models is rapidly increasing. Therefore new methods and standards are needed for model design. A new language, Modelica, has been proposed by an international design committee as a standard, object-oriented, ... Keywords: CAD, SolidWorks, Mechanical modeling, Simulation, Animation, Visualization, Modeling languages, Modelica, OpenGL

Hakan Larsson

1999-07-01T23:59:59.000Z

144

Anisotropic damage modelling of biaxial behaviour and rupture of concrete structures  

E-Print Network [OSTI]

Continuum Damage Mechanics at the Representative Element Volume scale is a relevant tool to deal with largeAnisotropic damage modelling of biaxial behaviour and rupture of concrete structures Ragueneau F with damage induced anisotropy modelling for concrete-like materials. A thermodynamics based constitutive

Boyer, Edmond

145

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

SciTech Connect (OSTI)

Disordering mechanisms in graphite have a long history with conflicting viewpoints. Using Raman and x-ray photon spectroscoy, 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.

Eapen, Jacob; Murty, Korukonda; Burchell, Timothy

2014-06-02T23:59:59.000Z

146

hal-00878684,version1-30Oct2013 ings, deep reservoirs, confined pillars, etc. An accurate mechanical model is especially  

E-Print Network [OSTI]

mechanical model is especially needed in the analysis of damage, aging and degradation phenomena. Following identified by Ortiz (1985), whose model, based on mixture the- ory and damage mechanics, met most Mechanics, introducing phenomenological damage variables. Although damage is inherently a non isotropic

Boyer, Edmond

147

Continuum and Three-Nucleon Force Effects on 9Be Energy Levels  

E-Print Network [OSTI]

We extend the recently proposed ab initio no-core shell model with continuum to include three-nucleon (3N) interactions beyond the few-body domain. The extended approach allows for the assessment of effects of continuum degrees of freedom as well as of the 3N force in ab initio calculations of structure and reaction observables of p- and lower-sd-shell nuclei. As first application we concentrate on energy levels of the 9Be system for which all excited states lie above the n-8Be threshold. For all energy levels, the inclusion of the continuum significantly improves the agreement with experiment, which was an issue in standard no-core shell model calculations. Furthermore, we find the proper treatment of the continuum indispensable for reliable statements about the quality of the adopted 3N interaction from chiral effective field theory. In particular, we find the 1/2+ resonance energy, which is of astrophysical interest, in good agreement with experiment.

Joachim Langhammer; Petr Navratil; Sofia Quaglioni; Guillaume Hupin; Angelo Calci; Robert Roth

2014-11-10T23:59:59.000Z

148

Continuum and Three-Nucleon Force Effects on 9Be Energy Levels  

E-Print Network [OSTI]

We extend the recently proposed ab initio no-core shell model with continuum to include three-nucleon (3N) interactions beyond the few-body domain. The extended approach allows for the assessment of effects of continuum degrees of freedom as well as of the 3N force in ab initio calculations of structure and reaction observables of p- and lower-sd-shell nuclei. As first application we concentrate on energy levels of the 9Be system for which all excited states lie above the n-8Be threshold. For all energy levels, the inclusion of the continuum significantly improves the agreement with experiment, which was an issue in standard no-core shell model calculations. Furthermore, we find the proper treatment of the continuum indispensable for reliable statements about the quality of the adopted 3N interaction from chiral effective field theory. In particular, we find the 1/2+ resonance energy, which is of astrophysical interest, in good agreement with experiment.

Langhammer, Joachim; Quaglioni, Sofia; Hupin, Guillaume; Calci, Angelo; Roth, Robert

2014-01-01T23:59:59.000Z

149

ccsd00001253 The exploration process of inhomogeneous continuum  

E-Print Network [OSTI]

ccsd­00001253 (version 1) : 8 Mar 2004 The exploration process of inhomogeneous continuum random) that arise as weak limits of birthday trees. We give a description of the exploration process, a function de words: Continuum random tree, exchangeable increments, exploration process, L#19;evy process, weak

150

Continuum Robot Arms Inspired by Cephalopods Ian D. Walkera  

E-Print Network [OSTI]

Continuum Robot Arms Inspired by Cephalopods Ian D. Walkera , Darren M. Dawsona , Tamar Flashb in the development of a new class of soft, continuous backbone ("continuum") robot manipulators. Our work is strongly to delicate tasks in cluttered and/or unstructured environments. Our aim is to endow these compliant robotic

Kier, William M.

151

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

SciTech Connect (OSTI)

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.

Horoi, Mihai [Department of Physics, Central Michigan University, Mount Pleasant, Michigan, 48859 (United States)

2013-12-30T23:59:59.000Z

152

Hydro-Mechanical Coupling in Damaged Porous Media Containing Isolated Cracks or/and Vugs: Model and Computations  

E-Print Network [OSTI]

Hydro-Mechanical Coupling in Damaged Porous Media Containing Isolated Cracks or/and Vugs: Model In this paper we present the development of the macroscopic model describing the hydro-mechanical coupling model in the micro-porous domain saturated by a fluid. In the crack/vug domain the Stokes equation

Paris-Sud XI, Université de

153

Patient-specific modelling of whole heart anatomy, dynamics and haemodynamics from four-dimensional cardiac CT images  

Science Journals Connector (OSTI)

...which are the standard continuum mechanics...intricate dynamics of interfaces between different...figure-4). The interface location is used...the solid. The interface location is used...model with a one-dimensional systemic vascular...heart model. By measuring geometrically the...

2011-01-01T23:59:59.000Z

154

Comparison of problem model change mechanisms issued from CSP and TRIZ  

E-Print Network [OSTI]

1 Comparison of problem model change mechanisms issued from CSP and TRIZ RRoollaanndd DDee GGuuiioo satisfaction problem (CSP), on the other hand. Keywords: over-constrained problems, dialectical methods issued from CSP and TRIZ 2 · a set of evaluation parameters, which represent the objective of the problem

Paris-Sud XI, Université de

155

MODEL OF MECHANISM BEHAVIOR FOR VERIFICATION OF PLC Jos M. Machado  

E-Print Network [OSTI]

MODEL OF MECHANISM BEHAVIOR FOR VERIFICATION OF PLC PROGRAMS José M. Machado University of Minho on formal methods is now available for checking PLC (Programmable Logic Controller) programs. To verify a PLC program, it is necessary to consider a set of properties to prove and one of the most interesting

Paris-Sud XI, Université de

156

Rotary Electrodynamics of a DC Motor: Motor as Mechanical Capacitor Lab 2: Modeling and System Identification  

E-Print Network [OSTI]

). · im is the current through the motor. Because the motor is in series with all other electrical). Because power is conserved, m = Kmim (motor efficiency is actually closer to 69%). Here, Km 0.00767 VRotary Electrodynamics of a DC Motor: Motor as Mechanical Capacitor Lab 2: Modeling and System

157

Towards Model-Based Estimation of the Cardiac Electro-Mechanical Activity from ECG Signals  

E-Print Network [OSTI]

Towards Model-Based Estimation of the Cardiac Electro-Mechanical Activity from ECG Signals by comparing the actual patient's ECG with computational results and the deformation of the biomechani- cal-to-access measurements on a patient: the ECG (Electrocardiogram), and a time sequence of volumetric ultrasound images

Coudière, Yves

158

Lumped thermal model for switched reluctance motor applied to mechanical design optimization  

Science Journals Connector (OSTI)

Switched reluctance motors (SRM) are attracting much attention because of their special advantages. Generated heat, due to losses, can reduce the life time of SRMs. Therefore, taking into account thermal modeling helps to improve their performance and increase their life time. In this paper, a lumped thermal model of SRM based on the analogue circuit of conductive and convective thermal resistances is proposed. First the heat transfer equations were applied for modeling of each motor part as a thermal equivalent circuit. Then, the thermal modeling of whole SRM was done via assembling all these sub-circuits. For validity of the obtained model on a wide range of geometrical and structural properties of motor, apt heat transfer relations have been used. This comprehensive model is used to investigate the influence of dimensions on heat transfer in SRM. Finally, an optimal design of the stator yoke dimensions has been reached concerning the mechanical aspects without degrading electromagnetic characteristics of SRM.

Hossein Rouhani; Jawad Faiz; Caro Lucas

2007-01-01T23:59:59.000Z

159

Exact eigenvalues of the pairing Hamiltonian using continuum level density  

Science Journals Connector (OSTI)

The pairing Hamiltonian constitutes an important approximation in many-body systems; it is exactly soluble and quantum integrable. On the other hand, the continuum single-particle level density (CSPLD) contains information about the continuum energy spectrum. The question of whether one can use the Hamiltonian with constant pairing strength for correlations in the continuum is still unanswered. In this paper we generalize the Richardson exact solution for the pairing Hamiltonian including correlations in the continuum. The resonant and nonresonant continua are included through the CSPLD. The resonant correlations are made explicit by using the Cauchy theorem. Low-lying states with seniority 0 and 2 are calculated for the even carbon isotopes. We conclude that energy levels can indeed be calculated with constant pairing in the continuum using the CSPLD. It is found that the nucleus 24C is unbound. The real and complex energy representations of the continuum is developed and their differences are shown. The trajectory of the pair energies in the continuum for the nucleus 28C is shown.

R. Id Betan

2012-06-07T23:59:59.000Z

160

Implementation and Application of SAPRC07 and MCM Mechanisms in the Multi-scale Community Air Quality Model  

E-Print Network [OSTI]

mechanism. In this study, two state-of-the-science photochemical mechanisms, SAPRC07 and Master Chemical Mechanism (MCM) v3.1, were implemented in the Community Multi-scale Air Quality Model (CMAQ) version 4.6 developed by the US EPA to study a high ozone (O...

Li, Jingyi

2012-02-14T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

THE DETONATION MECHANISM OF THE PULSATIONALLY ASSISTED GRAVITATIONALLY CONFINED DETONATION MODEL OF Type Ia SUPERNOVAE  

SciTech Connect (OSTI)

We describe the detonation mechanism composing the 'pulsationally assisted' gravitationally confined detonation (GCD) model of Type Ia supernovae. This model is analogous to the previous GCD model reported in Jordan et al.; however, the chosen initial conditions produce a substantively different detonation mechanism, resulting from a larger energy release during the deflagration phase. The resulting final kinetic energy and {sup 56}Ni yields conform better to observational values than is the case for the 'classical' GCD models. In the present class of models, the ignition of a deflagration phase leads to a rising, burning plume of ash. The ash breaks out of the surface of the white dwarf, flows laterally around the star, and converges on the collision region at the antipodal point from where it broke out. The amount of energy released during the deflagration phase is enough to cause the star to rapidly expand, so that when the ash reaches the antipodal point, the surface density is too low to initiate a detonation. Instead, as the ash flows into the collision region (while mixing with surface fuel), the star reaches its maximally expanded state and then contracts. The stellar contraction acts to increase the density of the star, including the density in the collision region. This both raises the temperature and density of the fuel-ash mixture in the collision region and ultimately leads to thermodynamic conditions that are necessary for the Zel'dovich gradient mechanism to produce a detonation. We demonstrate feasibility of this scenario with three three-dimensional (3D), full star simulations of this model using the FLASH code. We characterized the simulations by the energy released during the deflagration phase, which ranged from 38% to 78% of the white dwarf's binding energy. We show that the necessary conditions for detonation are achieved in all three of the models.

Jordan, G. C. IV; Graziani, C.; Weide, K.; Norris, J.; Hudson, R.; Lamb, D. Q. [Flash Center for Computational Science, University of Chicago, Chicago, IL 60637 (United States); Fisher, R. T. [Department of Physics, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02740 (United States); Townsley, D. M. [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Meakin, C. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Reid, L. B. [NTEC Environmental Technology, Subiaco WA 6008 (Australia)

2012-11-01T23:59:59.000Z

162

A Source for Ultrafast Continuum Infrared and Terahertz Radiation  

E-Print Network [OSTI]

A compact and stable method for generating high-intensity linearly polarized continuum mid-IR and terahertz light using ultrafast femtosecond (fs) laser pulses is demonstrated. Continuous light generation from <400cm?1 ...

Petersen, Poul B.

163

Hybrid atomistic-continuum formulations for gaseous flows  

E-Print Network [OSTI]

Hybrid atomistic-continuum formulations allow the simulation of complex hydrodynamic phenomena at the nano and micro scales without the prohibitive cost of a fully atomistic approach. This is achieved through a domain ...

Wijesinghe, Hettithanthrige Sanith, 1974-

2003-01-01T23:59:59.000Z

164

Models of stochastic, spatially varying stress in the crust compatible with focal mechanism data Smith and Heaton 1  

E-Print Network [OSTI]

Models of stochastic, spatially varying stress in the crust compatible with focal mechanism data, spatially varying stress in the crust compatible with focal mechanism data ­ Smith and Heaton 3 Introduction ­ Smith and Heaton 1 Models of stochastic, spatially varying stress in the crust compatible with focal

Greer, Julia R.

165

Thermo-Hydrological-Mechanical Analysis of a Clay Barrier for Radioactive Waste Isolation: Probabilistic Calibration and Advanced Modeling  

E-Print Network [OSTI]

............................................................................. 129 5.2 Micro Structural Model .............................................................................. 136 5.3 Interaction Between Micro and Macro Structures ..................................... 138 6. MODELING OF FULL SCALE FEBEX INSITU... Conditions .................................................... 154 6.2.4 Results of Thermo-Hydro-Mechanical Analysis ............................ 156 6.2.5 Analysis of Mechanical Behavior .................................................. 161 6...

Dontha, Lakshman

2012-07-16T23:59:59.000Z

166

Continuum Thermodynamics of the SU(N) Gauge Theory  

E-Print Network [OSTI]

The thermodynamics of the deconfined phase of the SU(N) gauge theory is studied. Careful study is made of the approach to the continuum limit. The latent heat of the deconfinement transition is studied, for the theories with 3, 4 and 6 colors. Continuum estimates of various thermodynamic quantities are studied, and the approach to conformality investigated. The bulk thermodynamic quantities at different N are compared, to investigate the validity of 't Hooft scaling at these values of N.

Saumen Datta; Sourendu Gupta

2010-12-30T23:59:59.000Z

167

Relativistic corrections and non-Gaussianity in radio continuum surveys  

SciTech Connect (OSTI)

Forthcoming radio continuum surveys will cover large volumes of the observable Universe and will reach to high redshifts, making them potentially powerful probes of dark energy, modified gravity and non-Gaussianity. We consider the continuum surveys with LOFAR, WSRT and ASKAP, and examples of continuum surveys with the SKA. We extend recent work on these surveys by including redshift space distortions and lensing convergence in the radio source auto-correlation. In addition we compute the general relativistic (GR) corrections to the angular power spectrum. These GR corrections to the standard Newtonian analysis of the power spectrum become significant on scales near and beyond the Hubble scale at each redshift. We find that the GR corrections are at most percent-level in LOFAR, WODAN and EMU surveys, but they can produce O(10%) changes for high enough sensitivity SKA continuum surveys. The signal is however dominated by cosmic variance, and multiple-tracer techniques will be needed to overcome this problem. The GR corrections are suppressed in continuum surveys because of the integration over redshift — we expect that GR corrections will be enhanced for future SKA HI surveys in which the source redshifts will be known. We also provide predictions for the angular power spectra in the case where the primordial perturbations have local non-Gaussianity. We find that non-Gaussianity dominates over GR corrections, and rises above cosmic variance when f{sub NL}?>5 for SKA continuum surveys.

Maartens, Roy [Physics Department, University of the Western Cape, Cape Town 7535 (South Africa); Zhao, Gong-Bo; Bacon, David; Koyama, Kazuya [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Raccanelli, Alvise, E-mail: Roy.Maartens@port.ac.uk, E-mail: Gong-bo.Zhao@port.ac.uk, E-mail: David.Bacon@port.ac.uk, E-mail: Kazuya.Koyama@port.ac.uk, E-mail: alvise@caltech.edu [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91109 (United States)

2013-02-01T23:59:59.000Z

168

Imaging spectrophotometry of ionized gas in NGC 1068. III - Anisotropic excitation of the large-scale disk by scattering of nuclear continuum  

SciTech Connect (OSTI)

Photoionization of the solar abundance diffuse ionized media (DIM) in NGC 1068 by anisotropic nuclear emission is studied. It is shown that the emission characteristics can be understood in the light of the developing picture of the galaxy in which its intrinsic type 1 Seyfert nucleus, concealed by an obscuring medium, is visible only through scattered, polarized light. The gas excitation is anisotropic, the high-excitation gas along the jet axis being photoionized by direct nuclear continuum, while the lower excitation gas away from the axis sees only indirect nuclear emission scattered into it. A model of low optical depth, near-nuclear Thomson scattering is considered in detail, and it is shown that, even with moderate dust extinction, this mechanism is sufficient to energize the DIM. 56 refs.

Sokolowski, J.; Bland-hawthorn, J.; Cecil, G. (Rice University, Houston, TX (USA) North Carolina, University, Chapel Hill (USA))

1991-07-01T23:59:59.000Z

169

Modelling the Thermo-Mechanical Behavior of Magnesium Alloys during Indirect Extrusion  

SciTech Connect (OSTI)

One of the basic metal forming process for semi-finished products is extrusion. Since extrusion involves complex thermo-mechanical and multiaxial loading conditions resulting in large strains, high strain rates and an increase in temperature due to deformation, a proper yield criterion and hardening law should be used in the numerical modelling of the process. A phenomenological model based on a plastic potential has been proposed that takes strain, strain rate and temperature dependency on flow behaviour into consideration. A hybrid methodology of experiment and finite element simulation has been adopted in order to obtain necessary model parameters. The anisotropy/asymmetry in yielding was quantified by tensile and compression tests of specimens prepared from different directions. The identification of the corresponding model parameters was performed by a genetic algorithm. A fully coupled thermo-mechanical analysis has been used in extrusion simulations for calculation of the temperature field by considering heat fluxes and heat generated due to plastic deformation. The results of the approach adopted in this study appeared to be successful showing promising predictions of the experiments and thus may be extended to be applicable to other magnesium alloys or even other hcp metals.

Steglich, D. [GKSS Research Centre, Geesthacht (Germany); G.I.F.T., POSTECH, Pohang, Gyeongbuk (Korea, Republic of); Ertuerk, S.; Bohlen, J.; Letzig, D. [GKSS Research Centre, Geesthacht (Germany); Brocks, W. [Faculty of Engineering, Christian-Albrechts-University of Kiel (Germany)

2010-06-15T23:59:59.000Z

170

A fully resolved active musculo-mechanical model for esophageal transport  

E-Print Network [OSTI]

Esophageal transport is a physiological process that mechanically transports an ingested food bolus from the pharynx to the stomach via the esophagus, a multi-layered muscular tube. This process involves interactions between the bolus, the esophagus, and the neurally coordinated activation of the esophageal muscles. In this work, we use an immersed boundary (IB) approach to simulate peristaltic transport in the esophagus. The bolus is treated as a viscous fluid that is actively transported by the muscular esophagus, which is modeled as an actively contracting, fiber-reinforced tube. A simplified version of our model is verified by comparison to an analytic solution to the tube dilation problem. Three different complex models of the multi-layered esophagus, which differ in their activation patterns and the layouts of the mucosal layers, are then extensively tested. To our knowledge, these simulations are the first of their kind to incorporate the bolus, the multi-layered esophagus tube, and muscle activation i...

Kou, Wenjun; Griffith, Boyce E; Pandolfino, John E; Kahrilas, Peter J; Patankar, Neelesh A

2015-01-01T23:59:59.000Z

171

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

SciTech Connect (OSTI)

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 Poisson’s 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.

Freed, Alan D.; Einstein, Daniel R.

2011-04-14T23:59:59.000Z

172

Fluid Dynamics and Solid Mechanics, T-3: Theoretical, T: LANL Inside  

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

Leader Leader Mark Schraad Deputy Group Leader Marianne Francois Administration Crystal Martinez Beverly Corrales Office Location MS B216 TA-3, Bldg 200, Rm 215 Fluid Dynamics and Solid Mechanics, T-3 Conducts basic and applied research in theoretical continuum dynamics, modern hydrodynamic theory, materials modeling, global climate modeling, numerical algorithm development, and large-scale computational simulations. There is an emphasis on developing advanced numerical methods for continuum dynamics at all flow velocities and strain rates, and coupling these methods to constitutive models for solid material response and other physical processes such as turbulence, chemical reactions, combustion, phase change, heat and mass transfer, and plasma behavior. The Fluid Dynamics Group's portfolio of research activities represents fundamental

173

Compensatory mechanisms in fish populations: Literature reviews: Volume 3, A critical review of mathematical models for fish compensation mechanisms: Final report  

SciTech Connect (OSTI)

A critical review of population dynamics models was performed to describe previous models and to recommend approaches for future research on compensation in fish population. The models were first classified into five categories, i.e., theoretical, stock-recruitment, biomass (bioenergetic), population (number), and life cycle functions. Models in each category were then reviewed for their formulations, assumptions, limitations, and performances. A majority of the models were found to have been formulated to calculate parameters that could not be directly measured. Models developed to evaluate entrainment and impingement impacts were often applied without validation against observed data. To advance the scientific understanding of fish compensation mechanisms, future research should include complimentary studies in both model development and empirical observation. Modeling will provide a theoretical framework to integrate individual compensation mechanisms and to relate them to population level responses. Empirical observation, on the other hand, will furnish data to verify the theory. The fish compensation model should use a cohort representation that allows the incorporation of the relationships between life cycle processes and environmental conditions. Growth and mortality of fish in early life stages should be related to weather, hydrology, temperature and food in addition to competition and predation. Environmental data with an inherent stochasticity should be used as input to produce verifiable real time variations in year class strength.

Chen, C.W.

1987-05-01T23:59:59.000Z

174

Mechanical defradation of Emplacement Drifts at Yucca Mountain- A Modeling Case Study. Part I: Nonlithophysal Rock  

SciTech Connect (OSTI)

This paper outlines rock mechanics investigations associated with mechanical degradation of planned emplacement drifts at Yucca Mountain, which is the designated site for the proposed U.S. high-level nuclear waste repository. The factors leading to drift degradation include stresses from the overburden, stresses induced by the heat released from the emplaced waste, stresses due to seismically related ground motions, and time-dependent strength degradation. The welded tuff emplacement horizon consists of two groups of rock with distinct engineering properties: nonlithophysal units and lithophysal units, based on the relative proportion of lithophysal cavities. The term 'lithophysal' refers to hollow, bubble like cavities in volcanic rock that are surrounded by a porous rim formed by fine-grained alkali feldspar, quartz, and other minerals. Lithophysae are typically a few centimeters to a few decimeters in diameter. Part I of the paper concentrates on the generally hard, strong, and fractured nonlithophysal rock. The degradation behavior of the tunnels in the nonlithophysal rock is controlled by the occurrence of keyblocks. A statistically equivalent fracture model was generated based on extensive underground fracture mapping data from the Exploratory Studies Facility at Yucca Mountain. Three-dimensional distinct block analyses, generated with the fracture patterns randomly selected from the fracture model, were developed with the consideration of in situ, thermal, and seismic loads. In this study, field data, laboratory data, and numerical analyses are well integrated to provide a solution for the unique problem of modeling drift degradation.

M. Lin; D. Kicker; B. Damjanac; M. Board; M. Karakouzian

2006-07-05T23:59:59.000Z

175

Hydro-mechanical modelling of geological CO2 storage and the study of possible caprock fracture mechanisms  

E-Print Network [OSTI]

to tensile stresses is treated. The stress intensity factor is used as the driving parameter describing mechanisms N. Guy,1-2 D.M. Seyedi,1 F. Hild2 BRGM, Natural Risks & CO2 Storage Safety Division, 3 av. Claude studies have shown that gas injection into deep permeable formations induce changes of the total

176

Domain growth in the random-field Ising model  

Science Journals Connector (OSTI)

We study a continuum random-field model of domain growth in quenched nonequilibrium systems. We derive an equation of motion for the interfaces separating domains and find approximate solutions for the growth laws in two and three dimensions. We find what may be a dynamical mechanism for the theoretical prediction that the lower critical dimension of this model is d1=2. Our theoretical predictions can be tested experimentally or by computer simulation.

Martin Grant and J. D. Gunton

1984-02-01T23:59:59.000Z

177

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

SciTech Connect (OSTI)

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)

Matijasevic, Milena; Al Mazouzi, Abderrahim [Reactor materials research, SCK-CEN, Mol (Belgium)

2008-07-01T23:59:59.000Z

178

On a 2D hydro-mechanical lattice approach for modelling hydraulic fracture  

E-Print Network [OSTI]

A 2D lattice approach to describe hydraulic fracturing is presented. The interaction of fluid pressure and mechanical response is described by Biot's theory. The lattice model is applied to the analysis of a thick-walled cylinder, for which an analytical solution for the elastic response is derived. The numerical results obtained with the lattice model agree well with the analytical solution. Furthermore, the coupled lattice approach is applied to the fracture analysis of the thick-walled cylinder. It is shown that the proposed lattice approach provides results that are independent of the mesh size. Moreover, a strong geometrical size effect on nominal strength is observed which lies between analytically derived lower and upper bounds. This size effect decreases with increasing Biot's coefficient.

Grassl, Peter; Gallipoli, Domenico; Wheeler, Simon J

2014-01-01T23:59:59.000Z

179

A Dual Model-Free Control of Underactuated Mechanical Systems, Application to The Inertia Wheel Inverted Pendulum  

E-Print Network [OSTI]

A Dual Model-Free Control of Underactuated Mechanical Systems, Application to The Inertia Wheel underac- tuated mechanical system: the inertia wheel inverted pendulum. Numerical simulations as well: the ball and beam [9] (where the dynamics of the beam has not been taken into account) and the Planar

Paris-Sud XI, Université de

180

A statistical, physical-based, micro-mechanical model of hydrogen-induced intergranular fracture in steel  

E-Print Network [OSTI]

with hydrogen embrittlement represents a particu- larly severe degradation mechanism in metallic structures and compressors, despite the fact that they can be extremely susceptible to such hydrogen embrittlementA statistical, physical-based, micro-mechanical model of hydrogen-induced intergranular fracture

Ritchie, Robert

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Continuum damage mechanics predictions of creep damage initiation and growth in ferritic steel weldments in a medium bore branched pipe under constant pressure at 590?°C using a five-material weld model  

Science Journals Connector (OSTI)

...to take place, by steam leakage, from the...studied thick section steam pipes fabricated...to be a valuable tool for the analysis...involved initial stress systems with inherent errors...analysis. A crude assessment of what might be...of time to first steam leak were 18h and...

2005-01-01T23:59:59.000Z

182

Continuum-based Multiscale Computational Damage Modeling of Cementitous Composites  

E-Print Network [OSTI]

of ? , and its comparison with experimental results by Kupfer et al. (1969) ...... 32 5.1 Evolution of the damage due to the change of the compressive hardening modulus Q ? for: (a) Exponential damage evolution law in Eq. (2.48) and (b) power damage... evolution law in Eq. (2.52) ............... 71 5.2 Evolution of the damage due to the change of the compressive hardening rate constant b? for: (a) Exponential damage evolution law in Eq. (2.48) and (b) power damage evolution law in Eq. (2...

Kim, Sun-Myung

2011-08-08T23:59:59.000Z

183

Continuum model of epithelial morphogenesis during Caenorhabditis elegans embryonic elongation  

Science Journals Connector (OSTI)

...defined using the fundamental assumption that...subjected to pulling forces and highly resilient...wormatlas.org/handbook/hypodermis...distribution of forces in the embryo...tensors express a fundamental strain measure...anisotropy is fundamental to elongate the...evenly distribute forces between cells...

2009-01-01T23:59:59.000Z

184

Optical lattices with exceptional points in the continuum  

E-Print Network [OSTI]

The spectral, dynamical and topological properties of physical systems described by non-Hermitian (including $\\mathcal{PT}$-symmetric) Hamiltonians are deeply modified by the appearance of exceptional points and spectral singularities. Here we show that exceptional points in the continuum can arise in non-Hermitian (yet admitting and entirely real-valued energy spectrum) optical lattices with engineered defects. At an exceptional point, the lattice sustains a bound state with an energy embedded in the spectrum of scattered states, similar to the von-Neumann Wigner bound states in the continuum of Hermitian lattices. However, the dynamical and scattering properties of the bound state at an exceptional point are deeply different from those of ordinary von-Neumann Wigner bound states in an Hermitian system. In particular, the bound state in the continuum at an exceptional point is an unstable state that can secularly grow by an infinitesimal perturbation. Such properties are discussed in details for transport of discretized light in a $\\mathcal{PT}$-symmetric array of coupled optical waveguides, which could provide an experimentally accessible system to observe exceptional points in the continuum.

S. Longhi; G. Della Valle

2014-05-30T23:59:59.000Z

185

Preprint UC Davis Math 199930 A continuum approximation for the  

E-Print Network [OSTI]

Preprint UC Davis Math 1999­30 A continuum approximation for the excitations of the (1; 1 and Shannon Starr Department of Mathematics University of California, Davis Davis, CA 95616­8633, USA bolina, with an appropriate scaling, the energy of low­ lying excitations of the (1; 1; : : : ; 1) interface in the d

186

Generating coherent broadband continuum soft-x-ray radiation by  

E-Print Network [OSTI]

Generating coherent broadband continuum soft-x-ray radiation by attosecond ionization gating Thomas as the driver for high-harmonic generation that has a cosine-like electric field stabilized with respect the generation of broadband and tunable attosecond pulses. Instead of fixing the carrier-envelope phase

Neumark, Daniel M.

187

Optimal Location of a Mobile Sensor Continuum for Environmental Monitoring  

E-Print Network [OSTI]

air pollution monitoring, seismic monitoring, or monitoring of large infrastructures in civil is proposed for the goal of optimal location of a mobile sensor continuum. The monitoring of pollution on a 2D or track distributed environmental phenomena (weather, seismic events, wildfires, air, soil or river

Boyer, Edmond

188

High-resolution terahertz atmospheric water vapor continuum measurements  

E-Print Network [OSTI]

High-resolution terahertz atmospheric water vapor continuum measurements David M. Slocum,* Thomas M such as pollution monitoring and the detection of energetic chemicals using remote sensing over long path lengths through the atmosphere. Although there has been much attention to atmospheric effects over narrow

Massachusetts at Lowell, University of

189

Temperature dependence of YbHe continuum emission spectra  

Science Journals Connector (OSTI)

We have observed laser-excited continuum emission spectra in the far wings of the 6s2 1S0–6s6p 1P1 resonance line of Yb broadened by He at seven different temperatures (405–560 °C). We find that the YbHe molecular excited state 6s6p ?1 is repulsive.

K. Ueda; H. Chiba; Y. Sato

1992-02-01T23:59:59.000Z

190

Mechanical Response and Decomposition of Thermally Degraded Energetic Materials: Experiments and Model Simulations  

SciTech Connect (OSTI)

We report progress of a continuing effort to characterize and simulate the response of energetic materials (EMs), primarily HMX-based, under conditions leading to cookoff. Our experiments include mechanical-effects testing of HMX and FIMX with binder at temperatures nearing decomposition thresholds. Additional experiments have focused on decomposition of these EMs under confinement, measuring evolution of gas products and observing the effect of pressurization on the solid. Real-time measurements on HMX show abrupt changes that maybe due to sudden void collapse under increasing load. Postmortem examination shows significant internal damage to the pellets, including voids and cracks. These experiments have been used to help develop a constitutive model for pure HMX. Unconfined uniaxial compression tests were performed on HMX and LX-14 to examine the effect of binders on the deviatoric strength of EM pellets, and to assess the need of including deviatoric terms in the model. A scale-up experiment will be described that is being developed to validate the model and provide additional diagnostics.

KANESHIGE,MICHAEL J.; RENLUND,ANITA M.; SCHMITT,ROBERT G.; WELLMAN,GERALD W.

1999-10-14T23:59:59.000Z

191

Three-body Interactions Improve the Prediction of Rate and Mechanism in Protein Folding Models  

E-Print Network [OSTI]

Here we study the effects of many-body interactions on rate and mechanism in protein folding, using the results of molecular dynamics simulations on numerous coarse-grained C-alpha-model single-domain proteins. After adding three-body interactions explicitly as a perturbation to a Go-like Hamiltonian with native pair-wise interactions only, we have found 1) a significantly increased correlation with experimental phi-values and folding rates, 2) a stronger correlation of folding rate with contact order, matching the experimental range in rates when the fraction of three-body energy in the native state is ~ 20%, and 3) a considerably larger amount of 3-body energy present in Chymotripsin inhibitor than other proteins studied.

M. R. Ejtehadi; S. P. Avall; S. S. Plotkin

2004-07-14T23:59:59.000Z

192

Tubular Enhanced Geodesic Active Contours for Continuum Robot Detection using 3D Ultrasound  

E-Print Network [OSTI]

Tubular Enhanced Geodesic Active Contours for Continuum Robot Detection using 3D Ultrasound continuum robots in 3D ultrasound images. The proposed approach combines geodesic active contours Enhanced Geodesic Active Contours (TEGAC), is demonstrated through ex vivo intracardiac experiments

Dupont, Pierre

193

Modeling of short-term mechanism of arterial pressure control in the cardiovascular system: Object-oriented and acausal approach  

Science Journals Connector (OSTI)

Abstract This letter introduces an alternative approach to modeling the cardiovascular system with a short-term control mechanism published in Computers in Biology and Medicine, Vol. 47 (2014), pp. 104–112. We recommend using abstract components on a distinct physical level, separating the model into hydraulic components, subsystems of the cardiovascular system and individual subsystems of the control mechanism and scenario. We recommend utilizing an acausal modeling feature of Modelica language, which allows model variables to be expressed declaratively. Furthermore, the Modelica tool identifies which are the dependent and independent variables upon compilation. An example of our approach is introduced on several elementary components representing the hydraulic resistance to fluid flow and the elastic response of the vessel, among others. The introduced model implementation can be more reusable and understandable for the general scientific community.

Tomáš Kulhánek; Ji?í Kofránek; Marek Mateják

2014-01-01T23:59:59.000Z

194

Modeling and implementation of solder-activated joints for single actuator, centimeter-scale robotic mechanisms  

E-Print Network [OSTI]

This thesis explains when, and why, solder-based phase change materials (PCMs) are best-suited as a means to modify a robotic mechanism's kinematic and elastomechanic behavior. The preceding refers to mechanisms that possess ...

Telleria, Maria J

2010-01-01T23:59:59.000Z

195

Exploring the mechanisms critical to the operation of metal face seals through modeling and experiments  

E-Print Network [OSTI]

This thesis aims to explore operation mechanisms of a special type of mechanical face seals: the flexible metal-to-metal face seal (FMMFS). Unique features of the FMMFS include much more flexibility in the circumferential ...

Wang, Yong, Ph. D. Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics

2008-01-01T23:59:59.000Z

196

Mechanism model for shale gas transport considering diffusion, adsorption/desorption and Darcy flow  

Science Journals Connector (OSTI)

To improve the understanding of the transport mechanism in shale gas reservoirs and build a theoretical basic for ... on productivity evaluation and efficient exploitation, various gas transport mechanisms within...

Ming-qiang Wei ???; Yong-gang Duan ???…

2013-07-01T23:59:59.000Z

197

First steps in VLA continuum data reduction with AIPS  

E-Print Network [OSTI]

://archive.nrao.edu/archive/bigquerypage.jsp. Once we have the uv­data file, the next step is to load it in AIPS. To do this, it is necessary continuum data reduction with AIPS A.1 Loading and inspecting the data To load typical uv­data files from the data. FILLM Using the FILLM task we load a uv­data file into AIPS. Multiple VLA archive files may

Estalella, Robert

198

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

SciTech Connect (OSTI)

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.

Not Available

2013-04-01T23:59:59.000Z

199

Some approaches for modeling and analysis of a parallel mechanism with stewart platform architecture  

SciTech Connect (OSTI)

Parallel mechanisms represent a family of devices based on a closed kinematic architecture. This is in contrast to serial mechanisms, which are comprised of a chain-like series of joints and links in an open kinematic architecture. The closed architecture of parallel mechanisms offers certain benefits and disadvantages.

V. De Sapio

1998-05-01T23:59:59.000Z

200

Continuum particle-vibration coupling method in coordinate-space representation for finite nuclei  

E-Print Network [OSTI]

In this paper we present a new formalism to implement the nuclear particle-vibration coupling (PVC) model. The key issue is the proper treatment of the continuum, that is allowed by the coordinate space representation. Our formalism, based on the use of zero-range interactions like the Skyrme forces, is microscopic and fully self-consistent. We apply it to the case of neutron single-particle states in $^{40}$Ca, $^{208}$Pb and $^{24}$O. The first two cases are meant to illustrate the comparison with the usual (i.e., discrete) PVC model. However, we stress that the present approach allows to calculate properly the effect of PVC on resonant states. We compare our results with those from experiments in which the particle transfer in the continuum region has been attempted. The latter case, namely $^{24}$O, is chosen as an example of a weakly-bound system. Such a nucleus, being double-magic and not displaying collective low-lying vibrational excitations, is characterized by quite pure neutron single-particle states around the Fermi surface.

Kazuhito Mizuyama; Gianluca Colò; Enrico Vigezzi

2012-05-04T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Three-dimensional Continuum Radiative Transfer Images of a Molecular Cloud Core Evolution  

E-Print Network [OSTI]

We analyze a three-dimensional smoothed particle hydrodynamics simulation of an evolving and later collapsing pre-stellar core. Using a three-dimensional continuum radiative transfer program, we generate images at 7 micron, 15 micron, 175 micron, and 1.3 mm for different evolutionary times and viewing angles. We discuss the observability of the properties of pre-stellar cores for the different wavelengths. For examples of non-symmetric fragments, it is shown that, misleadingly, the density profiles derived from a one-dimensional analysis of the corresponding images are consistent with one-dimensional core evolution models. We conclude that one-dimensional modeling based on column density interpretation of images does not produce reliable structural information and that multidimensional modeling is required.

J. Steinacker; B. Lang; A. Burkert; A. Bacmann; Th. Henning

2004-10-12T23:59:59.000Z

202

Sierra/solid mechanics 4.22 user's guide.  

SciTech Connect (OSTI)

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.

Thomas, Jesse David

2011-10-01T23:59:59.000Z

203

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

SciTech Connect (OSTI)

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.

Onishi, Y.; Serne, R.J.; Arnold, E.M.; Cowan, C.E.; Thompson, F.L. [Pacific Northwest Lab., Richland, WA (United States)

1981-01-01T23:59:59.000Z

204

Models of Stochastic, Spatially Varying Stress in the Crust Compatible with Focal-Mechanism Data, and How Stress Inversions  

E-Print Network [OSTI]

Models of Stochastic, Spatially Varying Stress in the Crust Compatible with Focal-Mechanism Data. Heaton Abstract Evidence suggests that slip in earthquakes and the resultant stress changes are spatially heterogeneous. If crustal stress from past earthquakes is spatially hetero- geneous, then earthquake focal

Greer, Julia R.

205

The mechanics of unrest at Long Valley caldera, California: 1. Modeling the geometry of the source using GPS,  

E-Print Network [OSTI]

The mechanics of unrest at Long Valley caldera, California: 1. Modeling the geometry of the source 44 existing leveling monuments in Long Valley caldera in July 1999, using dual frequency global in the Long Valley area and computed the vertical deformation by differencing GPS-based and leveled

Segall, Paul

206

Mechanical models of fracture reactivation and slip on bedding surfaces during folding of the asymmetric anticline at Sheep Mountain, Wyoming  

E-Print Network [OSTI]

Mechanical models of fracture reactivation and slip on bedding surfaces during folding June 2008 Accepted 5 June 2008 Available online 13 June 2008 Keywords: Fold Fracture reactivation Bed methods to investigate the reactivation of fractures (opening and shearing) and the development of bedding

Borja, Ronaldo I.

207

Fracture Modeling of Crack Propagation in Wood and Wood Composites Including Crack Tip Processes and Fiber Bridging Mechanics  

E-Print Network [OSTI]

1 Fracture Modeling of Crack Propagation in Wood and Wood Composites Including Crack Tip Processes and Fiber Bridging Mechanics J. A. Nairn, N. Matsumoto Wood Science & Engineering, Oregon State University wood and wood composites develop process zones often consisting of fibers bridging the crack surfaces

Nairn, John A.

208

Theory of continuum damping of toroidal Alfven Eigenmodes in finite-[beta] tokamaks  

SciTech Connect (OSTI)

We have formulated a general theoretical approach for analyzing two-dimensional structures of high-n Toroidal Alfven Eigenmodes (TAE) in large aspect-ratio, finite-[beta] tokamaks. Here, n is the toroidal wave number and [beta] is the ratio between plasma and magnetic pressures. The present approach generalizes the standard ballooning-mode formalism and is capable of treating eigenmodes with extended global radial structures as well as finite coupling between discrete and continuous spectra. Employing the well-known (s,[alpha]) model equilibrium and assuming a linear equilibrium profile, we have applied the present approach and calculated the corresponding resonant continuum damping rate of TAE modes. Here, s and [alpha] denote, respectively, the strengths of magnetic shear and pressure gradients. In particular, it is found that there exists a critical [alpha][sub c](s), such that, as [alpha] [yields] [alpha][sub c], the continuum damping rate is significantly enhanced and, thus, could suppress the potential TAE instability.

Zonca, F.; Chen, Liu.

1993-05-01T23:59:59.000Z

209

Theory of continuum damping of toroidal Alfven Eigenmodes in finite-{beta} tokamaks  

SciTech Connect (OSTI)

We have formulated a general theoretical approach for analyzing two-dimensional structures of high-n Toroidal Alfven Eigenmodes (TAE) in large aspect-ratio, finite-{beta} tokamaks. Here, n is the toroidal wave number and {beta} is the ratio between plasma and magnetic pressures. The present approach generalizes the standard ballooning-mode formalism and is capable of treating eigenmodes with extended global radial structures as well as finite coupling between discrete and continuous spectra. Employing the well-known (s,{alpha}) model equilibrium and assuming a linear equilibrium profile, we have applied the present approach and calculated the corresponding resonant continuum damping rate of TAE modes. Here, s and {alpha} denote, respectively, the strengths of magnetic shear and pressure gradients. In particular, it is found that there exists a critical {alpha}{sub c}(s), such that, as {alpha} {yields} {alpha}{sub c}, the continuum damping rate is significantly enhanced and, thus, could suppress the potential TAE instability.

Zonca, F.; Chen, Liu

1993-05-01T23:59:59.000Z

210

A model of multimedia components interconnection with support to communication mechanisms dynamic selection and reconfiguration  

Science Journals Connector (OSTI)

Distributed multimedia systems must provide support for interaction between its components, and this can be done by using different strategies and mechanisms of communication. A possible way to define efficient communication mechanisms is to consider ... Keywords: adaptation, communication, components, distributed multimedia systems, protocol of communication

Felipe A. P. Pinto; Adilson Barboza Lopes; André G. P. Silva; Daniel Cunha da Silva

2009-10-01T23:59:59.000Z

211

What happens to Lattice Fermion near Continuum Limit?  

E-Print Network [OSTI]

A Ginsparg-Wilson Relation (GWR) is obtained in the presence of chiral symmetry breaking terms. It leads to the PCAC relation as well as an anomaly relation on the lattice. For general fermions, the deviation from the exact GWR is getting small when the block-spin transformations are performed iteratively. Based on a simple geometrical interpretation of the Dirac operator satisfying the GWR, we find some physical properties shared by the lattice fermions near the continuum limit. In two-dimensions, we explicitly construct the GW Dirac operator by using a conformal mapping.

Minoru Koseki; Hiroto So; Naoya Ukita

2000-11-01T23:59:59.000Z

212

A two-path model on the effects of positivity and empathy reflected by online reviews: a choice mechanism perspective  

Science Journals Connector (OSTI)

This research uses the three choice mechanisms, i.e., cognitive, normative, and affective processes, to examine the impacts of two interrelated aspects regarding online reviews, i.e., positivity of online reviews and empathy reflected by online reviews, on online purchase intentions through two studies. Results reveal that positivity of online reviews is more strongly related to both cognitive and normative processing, whereas empathy reflected in response to searchers' problems is found to influence consumers' affective decision making, thus leading to the development of a two-path model regarding the psychological mechanisms about online reviews. Theoretical and managerial implications are discussed.

Xuehua Wang; Cheris W.C. Chow; Zhilin Yang

2012-01-01T23:59:59.000Z

213

LBNL-XXXXX | Logue et al., Evaluation of an Incremental Ventilation Energy Model for Estimating Impacts of Air Sealing and Mechanical Ventilation  

E-Print Network [OSTI]

Impacts of Air Sealing and Mechanical Ventilation 1 Evaluation of an Incremental Ventilation Energy Model for Estimating Impacts of Air Sealing and Mechanical Ventilation Jennifer M. Logue, William J. N for Estimating Impacts of Air Sealing and Mechanical Ventilation 2 Disclaimer This document was prepared

214

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

SciTech Connect (OSTI)

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.

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

1993-06-01T23:59:59.000Z

215

3D Modeling of Coupled Rock Deformation and Thermo-Poro-Mechanical Processes in Fractures  

E-Print Network [OSTI]

Problems involving coupled thermo-poro-chemo-mechanical processes are of great importance in geothermal and petroleum reservoir systems. In particular, economic power production from enhanced geothermal systems, effective water-flooding of petroleum...

Rawal, Chakra

2012-07-16T23:59:59.000Z

216

Magneto-Thermo-Mechanical Coupling, Stability Analysis and Phenomenological Constitutive Modeling of Magnetic Shape Memory Alloys  

E-Print Network [OSTI]

equations are then reduced to capture variant reorientation. A coupled magneto-mechanical boundary value problem (BVP) is solved that accounts for variant reorientation to investigate the influence of the demagnetization effect on the magnetic field...

Haldar, Krishnendu 1978-

2012-12-06T23:59:59.000Z

217

Physical understanding and modeling of chemical mechanical planarization in dielectric materials  

E-Print Network [OSTI]

Chemical mechanical planarization (CMP) has become the enabling planarization technique of choice for current and emerging silicon integrated circuit (IC) fabrication processes. This work studies CMP in dielectric materials ...

Xie, Xiaolin, Ph. D. Massachusetts Institute of Technology

2007-01-01T23:59:59.000Z

218

Mechanism-based constitutive modeling of L1? single-crystal plasticity  

E-Print Network [OSTI]

Ni3Al, an L12 structure intermetallic crystal, is the basic composition of the [gamma]' precipitates in nickel-based superalloys and is a major strengthening mechanism contributing to the superalloys' outstanding ...

Yin, Yuan, 1977-

2006-01-01T23:59:59.000Z

219

Mechanisms of Decadal Arctic Climate Variability in the Community Climate System Model, Version 2 (CCSM2)  

Science Journals Connector (OSTI)

Several mechanisms have been proposed to explain natural climate variability in the Arctic. These include processes related to the influence of the North Atlantic Oscillation/Arctic Oscillation (NAO/AO), anticyclonic/cyclonic regimes, changes in ...

Hugues Goosse; Marika M. Holland

2005-09-01T23:59:59.000Z

220

A study on aerodynamics and mechanisms of elementary morphing models for flapping wing in bat forward flight  

E-Print Network [OSTI]

The large active wing deformation is a significant way to generate high aerodynamic forces required in bat flapping flight. Besides the twisting, the elementary morphing models of a bat wing are proposed, such as wing-bending in the spanwise direction, wing-cambering in the chordwise direction, and wing area-changing. A plate of aspect ratio 3 is used to model a bat wing and a three dimensional unsteady panel method is applied to predict the aerodynamic forces. It is found that the cambering model has a great positive influence on the lift, followed by area-changing model and then the bending model. The further study indicates that the vortex control is a main mechanism to produce high aerodynamic forces, and the mechanisms for the aerodynamic force enhancement are the asymmetry of the cambered wing and the amplifier effects of wing area-changing and wing bending. The lift and thrust are mainly generated during the downstroke and almost negligible forces during the upstroke by the integrated morphing model-wi...

Zi-Wu, Guan

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Structural and mechanical properties of single-wall carbon nanotube fibers  

SciTech Connect (OSTI)

We report quantitative experimental study correlating the structure and mechanical properties of fibers made from single-walled carbon nanotubes (SWNTs) and polyvinyl alcohol (PVA). A post-synthesis solvent drawing treatment is used to vary nanotube alignment, whose detailed understanding is a prerequisite for fiber development. Quantitative analysis of nanotube alignment within the fibers with different draw ratios is performed using x-ray scattering. The method is described in detail, and we also show that the improvement of nanotube alignment with draw ratio can be understood within a model of induced orientation at constant volume. Young's modulus and tensile strength increase with nanotube alignment. This is modeled using continuum mechanics in qualitative agreement with experiment, however quantitative differences show that nanotube alignment is not the only parameter controlling the fiber mechanical properties. We suggest that interaction between the SWNTs and PVA chains should also play a significant role.

Pichot, V.; Albouy, P. A.; Launois, P. [Laboratoire de Physique des Solides (UMR CNRS 8502), bat 510, Universite Paris Sud, 91405 Orsay (France); Badaire, S.; Zakri, C.; Poulin, P. [Centre de Recherche Paul Pascal, CNRS, Universite Bordeaux I, avenue Schweitzer, 33600 Pessac (France)

2006-12-15T23:59:59.000Z

222

EMPIRICAL PREDICTIONS FOR (SUB-)MILLIMETER LINE AND CONTINUUM DEEP FIELDS  

SciTech Connect (OSTI)

Modern (sub-)millimeter/radio interferometers such as ALMA, JVLA, and the PdBI successor NOEMA will enable us to measure the dust and molecular gas emission from galaxies that have luminosities lower than the Milky Way, out to high redshifts and with unprecedented spatial resolution and sensitivity. This will provide new constraints on the star formation properties and gas reservoir in galaxies throughout cosmic times through dedicated deep field campaigns targeting the CO/[C II] lines and dust continuum emission in the (sub-)millimeter regime. In this paper, we present empirical predictions for such line and continuum deep fields. We base these predictions on the deepest available optical/near-infrared Advanced Camera for Surveys and NICMOS data on the Hubble Ultra Deep Field (over an area of about 12 arcmin{sup 2}). Using a physically motivated spectral energy distribution model, we fit the observed optical/near-infrared emission of 13,099 galaxies with redshifts up to z = 5, and obtain median-likelihood estimates of their stellar mass, star formation rate, dust attenuation, and dust luminosity. We combine the attenuated stellar spectra with a library of infrared emission models spanning a wide range of dust temperatures to derive statistical constraints on the dust emission in the infrared and (sub-)millimeter which are consistent with the observed optical/near-infrared emission in terms of energy balance. This allows us to estimate, for each galaxy, the (sub-)millimeter continuum flux densities in several ALMA, PdBI/NOEMA, and JVLA bands. As a consistency check, we verify that the 850 {mu}m number counts and extragalactic background light derived using our predictions are consistent with previous observations. Using empirical relations between the observed CO/[C II] line luminosities and the infrared luminosity of star-forming galaxies, we infer the luminosity of the CO(1-0) and [C II] lines from the estimated infrared luminosity of each galaxy in our sample. We then predict the luminosities of higher CO transition lines CO(2-1) to CO(7-6) based on two extreme gas excitation scenarios: quiescent (Milky Way) and starburst (M82). We use our predictions to discuss possible deep field strategies with ALMA. The predictions presented in this study will serve as a direct benchmark for future deep field campaigns in the (sub-)millimeter regime.

Da Cunha, Elisabete; Walter, Fabian; Decarli, Roberto; Rix, Hans-Walter [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany)] [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Bertoldi, Frank [Argelander Institute for Astronomy, University of Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany)] [Argelander Institute for Astronomy, University of Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany); Carilli, Chris [National Radio Astronomy Observatory, Pete V. Domenici Array Science Center, P.O. Box O, Socorro, NM 87801 (United States)] [National Radio Astronomy Observatory, Pete V. Domenici Array Science Center, P.O. Box O, Socorro, NM 87801 (United States); Daddi, Emanuele; Elbaz, David; Sargent, Mark [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d'Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette Cedex (France)] [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d'Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette Cedex (France); Ivison, Rob [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)] [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Maiolino, Roberto [Cavendish Laboratory, University of Cambridge, 19 J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom)] [Cavendish Laboratory, University of Cambridge, 19 J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Riechers, Dominik [Astronomy Department, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States)] [Astronomy Department, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Smail, Ian [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom)] [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Weiss, Axel, E-mail: cunha@mpia.de [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany)] [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany)

2013-03-01T23:59:59.000Z

223

Assessment of the importance of the pairing interaction in the continuum  

Science Journals Connector (OSTI)

A pairing interaction fitted to be applied in nuclei with active particles moving close to the continuum threshold or even immersed in the continuum itself is introduced. It is found that the effects of the nonresonant continuum upon physically meaningful quantities is unimportant. We applied the theory to heavy tin isotopes and good agreement between theory and the very few available experimental data is found.

R. Id Betan; G. G. Dussel; R. J. Liotta

2008-10-27T23:59:59.000Z

224

Mechanisms of aerosol-forced AMOC variability in a state of the art climate model  

E-Print Network [OSTI]

with a new state-of-the-art Earth system model. Anthropogenic aerosols have previously been highlighted anthropogenic aerosols force a strengthening of the AMOC by up to 20% in our state-of-the-art Earth system model

225

Continuum quasiparticle random phase approximation for astrophysical direct neutron capture reaction of neutron-rich nuclei  

E-Print Network [OSTI]

We formulate a many-body theory to calculate the cross section of direct radiative neutron capture reaction by means of the Hartree-Fock-Bogoliubov mean-field model and the continuum quasiparticle random phase approximation (QRPA). A focus is put on very neutron-rich nuclei and low-energy neutron kinetic energy in the range of O(1 keV) - O(1 MeV), relevant for the rapid neutron-capture process of nucleosynthesis. We begin with the photo-absorption cross section and the E1 strength function, then, in order to apply the reciprocity theorem, we decompose the cross section into partial cross sections corresponding to different channels of one- and two-neutron emission decays of photo-excited states. Numerical example is shown for the photo-absorption of $^{142}$Sn and the neutron capture of $^{141}$Sn.

Masayuki Matsuo

2014-10-31T23:59:59.000Z

226

Planck early results: Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources  

E-Print Network [OSTI]

Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalog (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, moving in the relativistic jet, shape the radio spectra. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper, physical modelli...

Aatrokoski, J; Aghanim, N; Aller, H D; Aller, M F; Angelakis, E; Arnaud, M; Ashdown, M; Aumont, J; Baccigalupi, C; Balbi, A; Banday, A J; Barreiro, R B; Bartlett, J G; Battaner, E; Benabed, K; Benoît, A; Berdyugin, A; Bernard, J -P; Bersanelli, M; Bhatia, R; Bonaldi, A; Bonavera, L; Bond, J R; Borrill, J; Bouchet, F R; Bucher, M; Burigana, C; Burrows, D N; Cabella, P; Capalbi, M; Cappellini, B; Cardoso, J -F; Catalano, A; Cavazzuti, E; Cayón, L; Challinor, A; Chamballu, A; Chary, R -R; Chiang, L -Y; Christensen, P R; Clements, D L; Colafrancesco, S; Colombi, S; Couchot, F; Coulais, A; Cutini, S; Cuttaia, F; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Gasperis, G; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Dickinson, C; Dole, H; Donzelli, S; Doré, O; Dörl, U; Douspis, M; Dupac, X; Efstathiou, G; Enßlin, T A; Finelli, F; Forni, O; Frailis, M; Franceschi, E; Fuhrmann, L; Galeotta, S; Ganga, K; Gargano, F; Gasparrini, D; Gehrels, N; Giard, M; Giardino, G; Giglietto, N; Giommi, P; Giordano, F; Giraud-Héraud, Y; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Harrison, D; Henrot-Versillé, S; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hovest, W; Hoyland, R J; Huffenberger, K M; Jaffe, A H; Juvela, M; Keihänen, E; Keskitalo, R; King, O; Kisner, T S; Kneissl, R; Knox, L; Krichbaum, T P; Kurki-Suonio, H; Lagache, G; Lähteenmäki, A; Lamarre, J -M; Lasenby, A; Laureijs, R J; Lavonen, N; Lawrence, C R; Leach, S; Leonardi, R; León-Tavares, J; Linden-V\\ornle, M; Lindfors, E; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maffei, B; Maino, D; Mandolesi, N; Mann, R; Maris, M; Martínez-González, E; Masi, S; Massardi, M; Matarrese, S; Matthai, F; Max-Moerbeck, W; Mazziotta, M N; Mazzotta, P; Melchiorri, A; Mendes, L; Mennella, A; Michelson, P F; Mingaliev, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Monte, C; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, A; Naselsky, P; Natoli, P; Nestoras, I; Netterfield, C B; Nieppola, E; Nilsson, K; N\\orgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; O'Dwyer, I J; Osborne, S; Pajot, F; Partridge, B; Pasian, F; Patanchon, G; Pavlidou, V; Pearson, T J; Perdereau, O; Perotto, L; Perri, M; Perrotta, F; Piacentini, F; Piat, M; Plaszczynski, S; Platania, P; Pointecouteau, E; Polenta, G; Ponthieu, N; Poutanen, T; Prézeau, G; Prunet, S; Puget, J -L; Rachen, J P; Rainó, S; Reach, W T; Readhead, A; Rebolo, R; Reeves, R; Reinecke, M; Reinthal, R; Renault, C; Ricciardi, S; Richards, J; Riller, T; Riquelme, D; Ristorcelli, I; Rocha, G; Rosset, C; Rowan-Robinson, M; Rubi\; Rusholme, B; Saarinen, J; Sandri, M; Savolainen, P; Scott, D; Seiffert, M D; Sievers, A; Sillanpää, A; Smoot, G F; Sotnikova, Y; Starck, J -L; Stevenson, M; Stivoli, F; Stolyarov, V; Sudiwala, R; Sygnet, J -F; Takalo, L; Tammi, J; Tauber, J A; Terenzi, L; Thompson, D J; Toffolatti, L; Tomasi, M; Tornikoski, M; Torre, J -P; Tosti, G; Tramacere, A; Tristram, M; Tuovinen, J; Türler, M; Turunen, M; Umana, G; Ungerechts, H; Valenziano, L; Valtaoja, E; Varis, J; Verrecchia, F; Vielva, P; Villa, F; Vittorio, N; Wandelt, B D; Wu, J; Yvon, D; Zacchei, A; Zensus, J A; Zhou, X; Zonca, A

2011-01-01T23:59:59.000Z

227

Mechanical properties and modeling of seal-forming lithologies. Technical progress report No. 2, March 15, 1991--March 14, 1992  

SciTech Connect (OSTI)

Both rocksalt and shale lithologies are actively deformed in response to gravitational loads associated with deposition, and both form effective seals to petroleum and natural gas. Thus, the shapes of seal-forming units, and the nature of fractures and faults that may breach them depend upon either the mechanical properties of salt or those of shale, and the loading histories to which they have been subjected. The objectives of this research include the determination of the mechanical properties under controlled conditions of well-characterized shales, and the numerical modeling of rocksalt (and eventually shale) formations using laboratory-based rheologies. Progress has been made towards these goals over this project period, both in our experimental program on shale deformation and model development for the growth of salt diapirs. The mechanical anisotropy of an illite-bearing shale from Louisiana has been determined and related to the preferred orientation and distribution of clays. Its strength in the absence of pore fluids has been determined at confining pressures of up to 250 MPa and at high pressure we have investigated the effects of deformation rate and temperature. A numerical finite difference code has been developed to solve the incompressible Navier-Stokes equations and validated using a two- layer linear viscous model for which analytic solutions are available. Although the code has only been validated for the linear viscous case, it is capable of solving for highly nonlinear constitutive laws as well as solving for arbitrary interfaces between the salt and overburden.

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

1992-04-01T23:59:59.000Z

228

Thermo-Mechanical Model Development and Validation of DirectedEnergy Deposition Additive Manufacturing of Ti-6Al-4V  

Science Journals Connector (OSTI)

Abstract A thermo-mechanical model of directed energy deposition additive manufacturing of Ti-6Al-4V is developed using measurements of the surface convection generated by gasses flowing during the deposition. In directed energy deposition, material is injected into a melt pool that is traversed to fill in a cross-section of a part, building it layer-by-layer. This creates large thermal gradients that generate plastic deformation and residual stresses. Finite element analysis (FEA) is often used to study these phenomena using simple assumptions of the surface convection. This work proposes that a detailed knowledge of the surface heat transfer is required to produce more accurate FEA results. The surface convection generated by the deposition process is measured and implemented in the thermo-mechanical model. Three depositions with different geometries and dwell times are used to validate the model using in situ measurements of the temperature and deflection as well as post-process measurements of the residual stress. An additional model is developed using the assumption of free convection on all surfaces. The results show that a measurement-based convection model is required to produce accurate simulation results.

J.C. Heigel; P. Michaleris; E.W. Reutzel

2014-01-01T23:59:59.000Z

229

Towards a taxonomy of syntactic and semantic matching mechanisms for aspect-oriented modeling  

Science Journals Connector (OSTI)

Aspect-oriented modeling (AOM) techniques have become increasingly popular over the last decade, as they enable improved modularity, separation of concerns, and reusability over conventional requirements and design modeling techniques. However, AOM notations ... Keywords: AoURN, aspect composition, aspect-oriented modeling, aspect-oriented user requirements notation, schema matching

Gunter Mussbacher; Daniele Barone; Daniel Amyot

2010-10-01T23:59:59.000Z

230

Modelling Quantum Mechanics by the Quantumlike Description of the Electric Signal Propagation in Transmission Lines  

E-Print Network [OSTI]

It is shown that the transmission line technology can be suitably used for simulating quantum mechanics. Using manageable and at the same time non-expensive technology, several quantum mechanical problems can be simulated for significant tutorial purposes. The electric signal envelope propagation through the line is governed by a Schrodinger-like equation for a complex function, representing the low-frequency component of the signal, In this preliminary analysis, we consider two classical examples, i.e. the Frank-Condon principle and the Ramsauer effect.

R. Fedele; M. A. Man'ko; V. I. Man'ko; V. G. Vaccaro

2002-07-30T23:59:59.000Z

231

The role of multiple chemotactic mechanisms in a model of chemotaxis in C. elegans: different mechanisms are specialised for different environments  

Science Journals Connector (OSTI)

Unlike simpler organisms, C. elegans possesses several distinct chemosensory pathways and chemotactic mechanisms. These mechanisms and pathways are individually capable of driving chemotaxis in a chemical concentration gradient. However, it ... Keywords: ASE, C. elegans, Chemotaxis, Sodium chloride

Peter A. Appleby

2014-06-01T23:59:59.000Z

232

Quantum Entanglement and Decoherence: Beyond Particle Models. A Farewell to Quantum Mechanics's Weirdness  

E-Print Network [OSTI]

Combining abstract to laboratory projected quantum states a general analysis of headline quantum phenomena is presented. Standard representation mode is replaced; instead quantum states sustained by elementary material constituents occupy its place. Renouncing to assign leading roles to language originated in classical physics when describing genuine quantum processes, together with sustainment concept most, if not all weirdness associated to Quantum Mechanics vanishes.

O. Tapia

2014-04-02T23:59:59.000Z

233

Carbon nanotube mats and fibers with irradiationimproved mechanical characteristics: a theoretical model  

E-Print Network [OSTI]

1 Carbon nanotube mats and fibers with irradiation­improved mechanical characteristics characteristics of macroscopic mats and fibers of single­walled carbon nanotubes. We further investigate, which in contrast to most ordinary carbon fibers could be strongly bent without breaking, had much

Nordlund, Kai

234

Carbon nanotube mats and fibers with irradiation-improved mechanical characteristics: a theoretical model  

E-Print Network [OSTI]

1 Carbon nanotube mats and fibers with irradiation-improved mechanical characteristics characteristics of macroscopic mats and fibers of single-walled carbon nanotubes. We further investigate]. The SWNT fibers, which in contrast to most ordinary carbon fibers could be strongly bent without breaking

Nordlund, Kai

235

Development and validation of a transition model based on a mechanical approximation  

E-Print Network [OSTI]

A new 3D transition turbulence model, more accurate and faster than an empirical transition model, is proposed. The model is based on the calculation of the pre-transitional u'v' due to mean flow shear. The present transition model is fully described and verified against eight benchmark test cases. Computations are performed for the ERCOFTAC flat-plate T3A, T3C and T3L test cases. Further, the model is validated for bypass, cross-flow and separation induced transition and compared with empirical transition models. The model presents very good results for bypass transition under zero-pressure gradient and with pressure gradient flow conditions. Also the model is able to correctly predict separation induced transition. However, for very low speed and low free-stream turbulence intensity the model delays separation induced transition onset. The model also shows very good results for transition under complex cross-flow conditions in three-dimensional geometries. The 3D tested case was the 6:1 prolate-spheroid und...

Vizinho, R; Silvestre, M

2015-01-01T23:59:59.000Z

236

NREL: Continuum Magazine - The Utility-Scale Future  

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

Utility-Scale Future Utility-Scale Future Issue 1 Print Version Share this resource Continuum Magazine Dan Says New Facility to Transform U.S. Energy Infrastructure New Facility to Transform U.S. Energy Infrastructure The nation's electricity infrastructure needs an overhaul. NREL's newest research facility will lead the way. Wind Innovation Enables Utility-Scale Wind Innovation Enables Utility-Scale NREL research will enable wind energy to make major contributions to meeting the nation's electrical demand. Leading Solar Expertise-A Launch Pad to the Future Leading 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 It Black: One-Step Etch Cuts Solar Cell Costs NREL's technique provides the solar cell manufacturing industry with a

237

Expectations for the Hard X-ray Continuum and Gamma-ray Line Fluxes from the Type Ia supernova SN 2014J in M82  

E-Print Network [OSTI]

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 $^{56}$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 upon the oftimes 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 $\\sim$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 $\\sim$thirty years. In support of these observational ...

The, Lih-Sin

2014-01-01T23:59:59.000Z

238

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...

239

Modelling and simulations of the chemo-mechanical behaviour of leached cement-based materials: Interactions between damage and leaching  

SciTech Connect (OSTI)

The assessment of the durability of cement-based materials, which could be employed in underground structures for nuclear waste disposal, requires accounting for deterioration factors, such as chemical attacks and damage, and for the interactions between these phenomena. The objective of the present paper consists in investigating the long-term behaviour of cementitious materials by simulating their response to chemical and mechanical solicitations. In a companion paper (Stora et al., submitted to Cem. Concr. Res. 2008), the implementation of a multi-scale homogenization model into an integration platform has allowed for evaluating the evolution of the mineral composition, diffusive and elastic properties inside a concrete material subjected to leaching. To complete this previous work, an orthotropic micromechanical damage model is presently developed and incorporated in this numerical platform to estimate the mechanical and diffusive properties of damaged cement-based materials. Simulations of the chemo-mechanical behaviour of leached cementitious materials are performed with the tool thus obtained and compared with available experiments. The numerical results are insightful about the interactions between damage and chemical deteriorations.

Stora, E., E-mail: stora@univ-mlv.f [Atomic Energy Commission, CEA Saclay DEN/DANS/DPC/SCCME/Laboratoire d'Etude du Comportement des Betons et des Argiles, 91191 Gif sur Yvette (France); Universite Paris-Est, Laboratoire de Modelisation et Simulation Multiechelle, FRE3160 CNRS, 5 boulevard Descartes, 77454 Marne-la-Vallee Cedex 2 (France); Bary, B. [Atomic Energy Commission, CEA Saclay DEN/DANS/DPC/SCCME/Laboratoire d'Etude du Comportement des Betons et des Argiles, 91191 Gif sur Yvette (France); He, Q.-C. [Universite Paris-Est, Laboratoire de Modelisation et Simulation Multiechelle, FRE3160 CNRS, 5 boulevard Descartes, 77454 Marne-la-Vallee Cedex 2 (France); Deville, E.; Montarnal, P. [CEA Saclay DEN/DANS/DM2S/SFME/MTMS, 91191 Gif sur Yvette (France)

2010-08-15T23:59:59.000Z

240

Mathematical model of IRIS replication mechanism for the simulation of tactical networks  

Science Journals Connector (OSTI)

The Multilateral Interoperability Programme (MIP) was established to promote more successful and better harmonized operational functions for international peace-keeping forces. The C2IEDM/JC3IEDM (Command and Control Information Exchange Data Model) ... Keywords: C2IS, Simulations, Tactical radio network, Traffic modeling

Joe Mohorko; Matja Fras

2009-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Project Profile: Predictive Physico-Chemical Modeling of Intrinsic Degradation Mechanisms for Advanced Reflector Materials  

Broader source: Energy.gov [DOE]

NREL, under the Physics of Reliability: Evaluating Design Insights for Component Technologies in Solar (PREDICTS) Program will be developing a physics-based computational degradation model to assess the kinetic oxidation rates; realistic model light attenuation and transport; and multi-layer treatment with variable properties Simulation based experimental design.

242

MECHANICAL TEST RESULTS ON DIPOLE MODEL C-l 25 mm ALUMINUM COLLARS  

E-Print Network [OSTI]

P~. FI'9 . ~ C.C rv'IW\\ 707~-Th ALUMINUM ' ~LAI2.. o Pl.ATTDIPOLE MODEL C-1 25 mm ALUMINUM COLLARS C. Peters FebruaryON DIPOLE MODEL C-I 25 mm ALUMINUM COLLARS· Craig Peters

Peters, C.

2010-01-01T23:59:59.000Z

243

ES2A7 -Fluid Mechanics Example Classes Model Answers to Example Questions (Set II)  

E-Print Network [OSTI]

of msvp = 2 -1 . Calculate the mean model wind tunnel speed if the model is made to 1/10 scale. Assume in a wind tunnel. The airspeed range to be investigated is at the docking end of its range, a maximum -=-=-= --- Question 4: Sliding Board #12;A board with an area slides down an inclined ramp as is schematically

Thomas, Peter J.

244

A density functional theory model of mechanically activated silyl ester hydrolysis  

SciTech Connect (OSTI)

To elucidate the mechanism of the mechanically activated dissociation of chemical bonds between carboxymethylated amylose (CMA) and silane functionalized silicon dioxide, we have investigated the dissociation kinetics of the bonds connecting CMA to silicon oxide surfaces with density functional calculations including the effects of force, solvent polarizability, and pH. We have determined the activation energies, the pre-exponential factors, and the reaction rate constants of candidate reactions. The weakest bond was found to be the silyl ester bond between the silicon and the alkoxy oxygen atom. Under acidic conditions, spontaneous proton addition occurs close to the silyl ester such that neutral reactions become insignificant. Upon proton addition at the most favored position, the activation energy for bond hydrolysis becomes 31 kJ?mol{sup ?1}, which agrees very well with experimental observation. Heterolytic bond scission in the protonated molecule has a much higher activation energy. The experimentally observed bi-exponential rupture kinetics can be explained by different side groups attached to the silicon atom of the silyl ester. The fact that different side groups lead to different dissociation kinetics provides an opportunity to deliberately modify and tune the kinetic parameters of mechanically activated bond dissociation of silyl esters.

Pill, Michael F.; Schmidt, Sebastian W. [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany) [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany); Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel (Germany); Center for Nanoscience (CeNS), Geschwister-Scholl-Platz 1, 80539 Munich (Germany); Beyer, Martin K. [Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel (Germany) [Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel (Germany); Institut für Ionenphysik und Angewandte Physik, Leopold-Franzens-Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck (Austria); Clausen-Schaumann, Hauke [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany) [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany); Center for Nanoscience (CeNS), Geschwister-Scholl-Platz 1, 80539 Munich (Germany); Kersch, Alfred, E-mail: akersch@hm.edu [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany)] [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany)

2014-01-28T23:59:59.000Z

245

Learning-Based Configuration Estimation of a Multi-Segment Continuum Robot  

E-Print Network [OSTI]

rotational accuracy in the range of 1 -2 is achieved. I. INTRODUCTION Continuum robots are continuously Orifice Translumenal Endoscopic Surgery (NOTES) [3]. Continuum robots have been investigated recently of accuracy due to friction, extension and torsion of their actuation lines, kinematic approximations

Simaan, Nabil

246

NUMERICAL MODELING FOR THE FORMATION MECHANISM OF 3D TOPOGRAPHY ON MICROBIAL MAT SURFACES  

E-Print Network [OSTI]

though, that nutrient limitation coupled with fluid motion may play a key role as a physical control. Under this model, competitions of nutrients were setup among growing microbial communities, which later evolve into specially arranged, 3D mats. However...

Patel, Harsh Jay

2013-09-27T23:59:59.000Z

247

Mechanism of the Water Gas Shift Reaction on Pt: First Principles, Experiments, and Microkinetic Modeling  

SciTech Connect (OSTI)

The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. We present a microkinetic model as well as experimental data for the low-temperature water gas shift (WGS) reaction catalyzed by Pt at temperatures from 523 to 573 K and for various gas compositions at a pressure of 1 atm. Thermodynamic and kinetic parameters for the model are derived from periodic, self-consistent density functional theory (DFT-GGA) calculations on Pt(111). The destabilizing effect of high CO surface coverage on the binding energies of surface species is quantified through DFT calculations and accounted for in the microkinetic model. Deviations of specific fitted model parameters from DFT calculated parameters on Pt(111) point to the possible role of steps/defects in this reaction. Our model predicts reaction rates and reaction orders in good agreement with our experiments. The calculated and experimental apparent activation energies are 67.8 kJ/mol and 71.4 kJ/mol, respectively. The model shows that the most significant reaction channel proceeds via a carboxyl (COOH) intermediate. Formate (HCOO), which has been experimentally observed and thought to be the key WGS intermediate in the literature, is shown to act only as a spectator species.

Grabow, Lars C.; Gokhale, Amit A.; Evans, Steven T.; Dumesic, James A.; Mavrikakis, Manos

2008-03-27T23:59:59.000Z

248

Controlling reactivity of nanoporous catalyst materials by tuning reaction product-pore interior interactions: Statistical mechanical modeling  

SciTech Connect (OSTI)

Statistical mechanical modeling is performed of a catalytic conversion reaction within a functionalized nanoporous material to assess the effect of varying the reaction product-pore interior interaction from attractive to repulsive. A strong enhancement in reactivity is observed not just due to the shift in reaction equilibrium towards completion but also due to enhanced transport within the pore resulting from reduced loading. The latter effect is strongest for highly restricted transport (single-file diffusion), and applies even for irreversible reactions. The analysis is performed utilizing a generalized hydrodynamic formulation of the reaction-diffusion equations which can reliably capture the complex interplay between reaction and restricted transport.

Wang, Jing [Ames Laboratory; Ackerman, David M. [Ames Laboratory; Lin, Victor S.-Y. [Ames Laboratory; Pruski, Marek [Ames Laboratory; Evans, James W. [Ames Laboratory

2013-04-02T23:59:59.000Z

249

Fracture mechanics models developed for piping reliability assessment in light water reactors: piping reliability project  

SciTech Connect (OSTI)

The efforts concentrated on modifications of the stratified Monte Carlo code called PRAISE (Piping Reliability Analysis Including Seismic Events) to make it more widely applicable to probabilistic fracture mechanics analysis of nuclear reactor piping. Pipe failures are considered to occur as the result of crack-like defects introduced during fabrication, that escape detection during inspections. The code modifications allow the following factors in addition to those considered in earlier work to be treated: other materials, failure criteria and subcritical crack growth characteristic; welding residual and vibratory stresses; and longitudinal welds (the original version considered only circumferential welds). The fracture mechanics background for the code modifications is included, and details of the modifications themselves provided. Additionally, an updated version of the PRAISE user's manual is included. The revised code, known as PRAISE-B was then applied to a variety of piping problems, including various size lines subject to stress corrosion cracking and vibratory stresses. Analyses including residual stresses and longitudinal welds were also performed.

Harris, D.O.; Lim, E.Y.; Dedhia, D.D.; Woo, H.H.; Chou, C.K.

1982-06-01T23:59:59.000Z

250

Spin Matrix Theory: A quantum mechanical model of the AdS/CFT correspondence  

E-Print Network [OSTI]

We introduce a new quantum mechanical theory called Spin Matrix theory (SMT). The theory is interacting with a single coupling constant g and is based on a Hilbert space of harmonic oscillators with a spin index taking values in a Lie algebra representation as well as matrix indices for the adjoint representation of U(N). We show that SMT describes N=4 super-Yang-Mills theory (SYM) near zero-temperature critical points in the grand canonical phase diagram. Equivalently, SMT arises from non-relativistic limits of N=4 SYM. Even though SMT is a non-relativistic quantum mechanical theory it contains a variety of phases mimicking the AdS/CFT correspondence. Moreover, the infinite g limit of SMT can be mapped to the supersymmetric sector of string theory on AdS_5 x S^5. We study SU(2) SMT in detail. At large N and low temperatures it is a theory of spin chains that for small g resembles planar gauge theory and for large g a non-relativistic string theory. When raising the temperature a partial deconfinement transit...

Harmark, Troels

2014-01-01T23:59:59.000Z

251

Persistent energy flow for a stochastic wave equation model in nonequilibrium statistical mechanics  

E-Print Network [OSTI]

We consider a one-dimensional partial differential equation system modeling heat flow around a ring. The system includes a Klein-Gordon wave equation for a field satisfying spatial periodic boundary conditions, as well as Ornstein-Uhlenbeck stochastic differential equations with finite rank dissipation and stochastic driving terms modeling heat baths. There is an energy flow around the ring. In the case of a linear field with different (fixed) bath temperatures, the energy flow can persist even when the interaction with the baths is turned off. A simple example is given.

Lawrence E. Thomas

2012-04-29T23:59:59.000Z

252

Physical process Mechanical mechanisms  

E-Print Network [OSTI]

1 Physical process Generation · Mechanical mechanisms F = m·a · Electric/Magnetic mechanisms F ­ Quadrupoles......shear stress fluctuations ­ High order poles...... phys. interpretation difficult Governing

Berlin,Technische Universität

253

Application of polymeric quenchant in heat treatment of crack-sensitive steel mechanical parts: Modeling and experiments  

Science Journals Connector (OSTI)

Success or failure of a quenching process is determined by selecting an appropriate quenchant. In this work, the quenching process of the automobile tie rods in different media including water, oil, and a polymeric solution was investigated. The microstructures and mechanical properties of the rods were predicted by a finite element simulation model. Several specimens were cut from the tie rods and heat treated by quenching in five different quenching media including water, oil, and PAG aqueous solutions with polymer concentrations of 10, 20, and 30%. The hardness tests and metallographic analyses were performed on the specimens. Considering the results of the simulations and the experiments, the optimum quenchant was selected and the tie rods were heat treated using this quenchant. The results showed that the use of Poly Alkylene Glycol (PAG) solution quenchants, with respect to its unique cooling mechanism, outperformed water and oil quenchants. The distortion and cracking was reduced compared to water quenching and, on the other hand, the mechanical properties which were not achievable by oil quenching were resulted using polymer-based quenching medium.

M. Eshraghi-Kakhki; M.A. Golozar; A. Kermanpur

2011-01-01T23:59:59.000Z

254

Small-energy series for one-dimensional quantum-mechanical models with non-symmetric potentials  

E-Print Network [OSTI]

We generalize a recently proposed small-energy expansion for one-dimensional quantum-mechanical models. The original approach was devised to treat symmetric potentials and here we show how to extend it to non-symmetric ones. Present approach is based on matching the logarithmic derivatives for the left and right solutions to the Schr\\"odinger equation at the origin (or any other point chosen conveniently) . As in the original method, each logarithmic derivative can be expanded in a small-energy series by straightforward perturbation theory. We test the new approach on four simple models, one of which is not exactly solvable. The perturbation expansion converges in all the illustrative examples so that one obtains the ground-state energy with an accuracy determined by the number of available perturbation corrections.

Paolo Amore; Francisco M. Fernández

2014-10-21T23:59:59.000Z

255

Lumped thermal model for switched reluctance motor applied to mechanical design optimization  

Science Journals Connector (OSTI)

Switched reluctance motors (SRM) are attracting much attention because of their special advantages. Generated heat, due to losses, can reduce the life time of SRMs. Therefore, taking into account thermal modeling helps to improve their performance and ... Keywords: Conduction, Convection, Motor losses, Optimal design, Switched reluctance motor, Thermal equivalent circuit

Hossein Rouhani; Jawad Faiz; Caro Lucas

2007-03-01T23:59:59.000Z

256

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.

257

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

SciTech Connect (OSTI)

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.

Kunwar, A., E-mail: amitbio@rediffmail.com [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Adhikary, B. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)] [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Jayakumar, S. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)] [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Barik, A. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)] [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Chattopadhyay, S. [Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)] [Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Raghukumar, S. [Myko Tech Private Limited, Dona Paula, Goa?403004 (India)] [Myko Tech Private Limited, Dona Paula, Goa?403004 (India); Priyadarsini, K.I., E-mail: kindira@barc.gov.in [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

2012-10-15T23:59:59.000Z

258

Tuning the Fano Resonance with an Intruder Continuum  

E-Print Network [OSTI]

Through a combination of experiment and theory we establish the possibility of achieving strong tuning of Fano resonances (FRs), by allowing their usual two-path geometry to interfere with an additional, 'intruder', continuum. As the coupling strength to this intruder is varied, we predict strong modulations of the resonance line shape that, in principle at least, may exceed the amplitude of the original FR itself. For a proof-of-concept demonstration of this phenomenon, we construct a nanoscale interferometer from nonlocally coupled quantum point contacts and utilize the unique features of their density of states to realize the intruder. External control of the intruder coupling is enabled by means of an applied magnetic field, in the presence of which we demonstrate the predicted distortions of the FR. This general scheme for resonant control should be broadly applicable to a variety of wave-based systems, opening up the possibility of new applications in areas such as chemical and biological sensing and secure communications.

J. Fransson; M. -G. Kang; Y. Yoon; S. Xiao; Y. Ochiai; J. L. Reno; N. Aoki; J. P. Bird

2014-03-11T23:59:59.000Z

259

Thermo-mechanical Characterization of Metal/Polymer Composite Filaments and Printing Parameter Study for Fused Deposition Modeling in the 3D Printing Process  

Science Journals Connector (OSTI)

New metal/polymer composite filaments for fused deposition modeling (FDM) processes were developed in order to observe the thermo-mechanical properties of the new filaments. The acrylonitrile butadiene styrene (A...

Seyeon Hwang; Edgar I. Reyes; Kyoung-sik Moon…

2014-10-01T23:59:59.000Z

260

A STATISTICAL STUDY OF THE SPECTRAL HARDENING OF CONTINUUM EMISSION IN SOLAR FLARES  

SciTech Connect (OSTI)

The observed hard X-ray and {gamma}-ray continuum in solar flares is interpreted as Bremsstrahlung emission of accelerated non-thermal electrons. It has been noted for a long time that in many flares the energy spectra show hardening at energies around or above 300 keV. In this paper, we first conduct a survey of spectral hardening events that were previously studied in the literature. We then perform a systematic examination of 185 flares from the Solar Maximum Mission. We identify 23 electron-dominated events whose energy spectra show clear double power laws. A statistical study of these events shows that the spectral index below the break ({gamma}{sub 1}) anti-correlates with the break energy ({epsilon}{sub b}). Furthermore, {gamma}{sub 1} also anti-correlates with Fr, the fraction of photons above the break compared to the total photons. A hardening spectrum, as well as the correlations between ({gamma}{sub 1}, {epsilon}{sub b}) and ({gamma}{sub 1}, Fr), provide stringent constraints on the underlying electron acceleration mechanism. Our results support a recent proposal that electrons are being accelerated diffusively at a flare termination shock with a width of the order of an ion inertial length scale.

Kong, X.; Chen, Y. [Institute of Space Sciences and School of Space Science and Physics, Shandong University, Weihai 264209 (China); Li, G., E-mail: xl_kong@hotmail.com, E-mail: gang.li@uah.edu [Department of Physics and CSPAR, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

2013-09-10T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Two-dimensional thermo-mechanical finite element model for laser cladding  

SciTech Connect (OSTI)

Temperature and stress fields during Laser Cladding determine, respectively, the microstructure and residual stress induced deformation and crack formation. As laser cladding processes find application in manufacturing, understanding of the temperature and stress fields becomes crucial for development of the relationship between process parameters and service behavior. A two-dimensional model of laser cladding is developed, using the finite element software package ABAQUS. It enables an investigation of the temperature field that develops at the center plane of the material. This temperature field provides the input for a thermal stress analysis, for which generalized plane strain was assumed. The goal of the present paper is to perform a quantitative evaluation of the residual stresses that develop at the two-layered material, as a function of process parameters such as scanning speed, laser power and powder feed rate. Results of the model are presented, as applied to cladding of C95600 on AA333.

Deus, A.M. de; Mazumder, J. [Univ. of Illinois, Urbana-Champaign, IL (United States)

1996-12-31T23:59:59.000Z

262

Hydrogen Balmer Continuum in Solar Flares Detected by the Interface Region Imaging Spectrograph (IRIS)  

E-Print Network [OSTI]

We present a novel observation of the white-light flare (WLF) continuum, which was significantly enhanced during the X1 flare on March 29, 2014 (SOL2014-03-29T17:48). Data from the Interface Region Imaging Spectrograph (IRIS) in its NUV channel show that at the peak of the continuum enhancement, the contrast at the quasi-continuum window above 2813 \\AA\\ reached 100 - 200 % and can be even larger closer to the Mg II lines. This is fully consistent with the hydrogen recombination Balmer continuum emission, which follows an impulsive thermal and non-thermal ionization caused by the precipitation of electron beams through the chromosphere. However, a less probable photospheric continuum enhancement cannot be excluded. The light curves of the Balmer continuum have an impulsive character with a gradual fading, similar to those detected recently in the optical region on Hinode/SOT. This observation represents a first Balmer-continuum detection from space far beyond the Balmer limit (3646 \\AA), eliminating seeing eff...

Heinzel, Petr

2014-01-01T23:59:59.000Z

263

Modeling shear failure and permeability enhancement due to coupled Thermal-Hydrological-Mechanical processes in Enhanced Geothermal Reservoirs  

SciTech Connect (OSTI)

The connectivity and accessible surface area of flowing fractures, whether natural or man-made, is possibly the single most important factor, after temperature, which determines the feasibility of an Enhanced Geothermal System (EGS). Rock deformation and in-situ stress changes induced by injected fluids can lead to shear failure on preexisting fractures which can generate microseismic events, and also enhance the permeability and accessible surface area of the geothermal formation. Hence, the ability to accurately model the coupled thermal-hydrologic-mechanical (THM) processes in fractured geological formations is critical in effective EGS reservoir development and management strategies. The locations of the microseismic events can serve as indicators of the zones of enhanced permeability, thus providing vital information for verification of the coupled THM models. We will describe a general purpose computational code, FEHM, developed for this purpose, that models coupled THM processes during multiphase fluid flow and transport in fractured porous media. The code incorporates several models of fracture aperture and stress behavior combined with permeability relationships. We provide field scale examples of applications to geothermal systems to demonstrate the utility of the method.

Kelkar, Sharad [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

264

Thermo-mechanical-metallurgical modeling for hot-press forming in consideration of the prior austenite deformation effect  

Science Journals Connector (OSTI)

Abstract In this study, a prior austenite grain refinement model was incorporated into semi-empirical diffusive transformation kinetics for application to hot-press forming. In particular, the kinetics equations were modified to include the effects of boron addition and austenite deformation on transformation behaviors during forming. To simulate the hot-press forming process, a thermo-mechanical-metallurgical model was formulated implicitly and implemented into the finite element program ABAQUS using the user subroutines UMAT and UMATHT. This nonconventional finite element modeling is appropriate to consider thermal- and transformation-associated strains. The proposed model was validated through simple finite element simulation examples, i.e., dilatometry simulation with and without external loading, and hot torsion and quenching of a rod. Finally, the hot-press forming of a U-channel-type part was simulated to study the effect of austenite deformation on the phase kinetics, hardness and residual stress. The simulation results showed that the austenite deformation had considerable influence on the final strength and residual stress distribution in the hot-press formed sheet, which resulted from an increase in ferritic phases due to the modified kinetics. In particular, the austenite deformation effect was more noticeable in the side-wall region of the U-channel where plastic deformation was the most severe.

Hyun-Ho Bok; JongWon Choi; Frédéric Barlat; Dong Woo Suh; Myoung-Gyu Lee

2014-01-01T23:59:59.000Z

266

COUPLED MECHANICAL AND HYDRAULIC MODELING OF GEOSYNTHETIC-REINFORCED COLUMN-SUPPORTED EMBANKMENTS  

E-Print Network [OSTI]

.2.5 Excess Pore Water Pressure 310 CHAPTER SIX COMPARISON OF TWO-DIMENSIONAL AND THREE DIMENSIONAL STUDIES 323 6.1 Verification of Simplified Model 324 6.2 2D and 3D Comparisons 329 6.2.1 Maximum Settlement and Distortion... 330 6.2.2 Maximum Tension Developed in Geosynthetics 342 6.2.3 Maximum Stress Concentration ratio 349 6.2.4 Excess Pore Water Pressure 356 6.2.5 Summary 363 CHAPTER SEVEN CONCLUSIONS AND RECOMMENDATIONS 367 7.1 Conclusions...

Huang, Jie

2007-12-14T23:59:59.000Z

267

Micromechanical model for elasticity of the cell cytoskeleton  

Science Journals Connector (OSTI)

Semiflexible polymer networks, such as cell cytoskeleton, differ significantly from their flexible counterparts in their deformation energy storage mechanism. As a result, the network elasticity is governed by both enthalpic and entropic variations. In addition, the enthalpic effect shows two distinct regimes of energy storage mechanism, the affine and nonaffine regimes. In the past, computation-based modeling on random networks, such as the Mikado model, was used to demonstrate the physical mechanism of mechanical deformation of semiflexible networks. These models are computationally intensive and hence are difficult to apply to studying whole cells. In this paper, we develop a micromechanical model to predict the average macroscopic elastic properties of a random, semiflexible, biopolymer network. The model employs a unit cell consisting of four semiflexible chains and four equivalent axial-bending springs. The proposed unit-cell-based micromechanical model represents a statistically average realization of the actual network and gives the average mechanical properties, such as the shear modulus. Comparisons between the model predictions and Mikado model results confirm that this micromechanical model captures the essential deformation physics revealed from previous studies on the actual network and is capable of predicting the transition between nonaffine and affine deformations. This model can be used to develop efficient continuum constitutive models of the cytoskeleton in the future.

Sitikantha Roy and H. Jerry Qi

2008-06-18T23:59:59.000Z

268

Sandia National Laboratories: Coupling Local to Nonlocal Continuum...  

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

is increasingly recognized as an essential aspect of high-fidelity modeling of the fracture and failure of solids. The nonlocal peridynamic model, while providing the key...

269

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)

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.

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

2013-03-01T23:59:59.000Z

270

Used Fuel Degradation: Experimental and Modeling Report  

Broader source: Energy.gov [DOE]

The report describes the strategy for coupling process level models to produce an integrated Used Fuel Degradation Model (FDM), and addresses fractional degradation rate, instant release fractions, other continuum modeling approaches, and experimental support.

271

Gaseous Chemistry and Aerosol Mechanism Developments for Version 3.5.1 of the Online Regional Model, WRF-Chem  

SciTech Connect (OSTI)

We have made a number of developments in the regional coupled model WRF-Chem, with the aim of making the model more suitable for prediction of atmospheric composition and of interactions between air quality and weather. We have worked on the European domain, with a particular focus on making the model suitable for the study of night time chemistry and oxidation by the nitrate radical in the UK atmosphere. A reduced form of the Common Reactive Intermediates gas-phase chemical mechanism (CRIv2-R5) has been implemented to enable more explicit simulation of VOC degradation. N2O5 heterogeneous chemistry has been added to the existing sectional MOSAIC aerosol module, and coupled to both the CRIv2-R5 and existing CBM-Z gas phase scheme. Modifications have also been made to the sea-spray aerosol emission representation, allowing the inclusion of primary organic material in sea-spray aerosol. Driven by appropriate emissions, wind fields and chemical boundary conditions, implementation of the different developments is illustrated in order to demonstrate the impact that these changes have in the North-West European domain. These developments are now part of the freely available WRF-Chem distribution.

Archer-Nicholls, Scott; Lowe, Douglas; Utembe, Steve; Allan, James D.; Zaveri, Rahul A.; Fast, Jerome D.; Hodnebrog, Oivind; Denier van der Gon, Hugo; McFiggans, Gordon

2014-11-08T23:59:59.000Z

272

mHealth Education Applications Along the Cancer Continuum  

Science Journals Connector (OSTI)

The majority of adults worldwide own a mobile phone, including those in under-resourced communities. Mobile health (mhealth) education technologies present a promising mechanism for ... summarize the literature r...

Sharon Watkins Davis; Ingrid Oakley-Girvan

2014-12-01T23:59:59.000Z

273

Configuration and Joint Feedback for Enhanced Performance of Multi-Segment Continuum Robots  

E-Print Network [OSTI]

and Natural Orifice Transluminal Endoscopic Surgery (NOTES) emphasize this need. Current designs of continuum algorithms in order to meet the desired accuracy. The lack of accuracy is due to friction, extension

Simaan, Nabil

274

Photodissociation of O2 via the Herzberg continuum: Measurements of O-atom alignment and orientation  

E-Print Network [OSTI]

resonantly enhanced multiphoton ionization 2 1 REMPI near 225 nm and the ions collected in a velocity regions: the Herzberg continuum 242­200 nm , the Schumann­Runge bands 200­176 nm , and the Schumann

Zare, Richard N.

275

Call for Presentations The GPGPU Continuum from mWatts to peta flops  

E-Print Network [OSTI]

Call for Presentations SAVE the DATE The GPGPU Continuum from mWatts to peta flops Organizing on using GPUs as part of mobile devices, which limits the power consumption of the GPU to mWatts. We

Schuster, Assaf

276

E-Print Network 3.0 - assessing continuum postulates Sample Search...  

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

Aleksandar Donev,1, John B... , Livermore, CA 94551-9900 A previously-developed hybrid particle-continuum method J. B. Bell, A. Garcia... dynamic coupling between the particle...

277

Thermal quasiparticle correlations and continuum coupling in nuclei far from stability  

Science Journals Connector (OSTI)

The contributions of quasiparticle correlations and of continuum coupling upon the superfluid properties of neutron-rich Ni isotopes are studied within the modified BCS (MBCS) approximation at finite temperature. The effect of quasiparticle correlations is included using a secondary Bogoliubov-type canonical transformation explicitly involving the quasiparticle occupation numbers at temperature T. The effect of continuum coupling is taken into account via the finite widths of the resonant states. It is shown that the combined effect of thermal quasiparticle correlations and of continuum coupling washes out the sharp superfluid-normal phase transition given by the standard finite-temperature BCS calculations. Within the proposed resonant-continuum MBCS approximation the fluctuations of particle number also become more suppressed especially at high temperature for nuclei closer to the drip line. Finally, it is found within the same approximation that the two-neutron separation energy for 84Ni drops to zero at T?0.8 MeV.

N. Dinh Dang and A. Arima

2003-01-16T23:59:59.000Z

278

Modelling of long-term and short-term mechanisms of arterial pressure control in the cardiovascular system: An object-oriented approach  

Science Journals Connector (OSTI)

A mathematical model that provides an overall description of both the short- and long-term mechanisms of arterial pressure regulation is presented. Short-term control is exerted through the baroreceptor reflex while renal elimination plays a role in ... Keywords: Cardiovascular system, DYMOLA simulation environment, MODELICA programming language, Object-oriented modelling, Pressure control

J. Fernandez De Canete, J. Luque, J. Barbancho, V. Munoz

2014-04-01T23:59:59.000Z

279

Microsoft Word - Evaluation of an Incremental Ventilation Energy Model for Estimating Impacts of Air Sealing and Mechanical Ventilation_Final2.docx  

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

XXXXX | Logue et al., Evaluation of an Incremental Ventilation Energy Model for Estimating XXXXX | Logue et al., Evaluation of an Incremental Ventilation Energy Model for Estimating Impacts of Air Sealing and Mechanical Ventilation 1 Evaluation of an Incremental Ventilation Energy Model for Estimating Impacts of Air Sealing and Mechanical Ventilation Jennifer M. Logue, William J. N. Turner, Iain S. Walker, and Brett C. Singer Environmental Energy Technologies Division June 2012 LBNL-5796E LBNL-XXXXX | Logue et al., Evaluation of an Incremental Ventilation Energy Model for Estimating Impacts of Air Sealing and Mechanical Ventilation 2 Disclaimer This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor The Regents of the University of California, nor

280

Modelling of long-term and short-term mechanisms of arterial pressure control in the cardiovascular system: An object-oriented approach  

Science Journals Connector (OSTI)

Abstract A mathematical model that provides an overall description of both the short- and long-term mechanisms of arterial pressure regulation is presented. Short-term control is exerted through the baroreceptor reflex while renal elimination plays a role in long-term control. Both mechanisms operate in an integrated way over the compartmental model of the cardiovascular system. The whole system was modelled in MODELICA, which uses a hierarchical object-oriented modelling strategy, under the DYMOLA simulation environment. The performance of the controlled system was analysed by simulation in light of the existing hypothesis and validation tests previously performed with physiological data, demonstrating the effectiveness of both regulation mechanisms under physiological and pathological conditions.

J. Fernandez de Canete; J. Luque; J. Barbancho; V. Munoz

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

From mechanical modeling to seismic imaging of faults: A synthetic workflow to study the impact of faults on seismic  

Science Journals Connector (OSTI)

Abstract Although typically interpreted as 2D surfaces, faults are 3D narrow zones of highly and heterogeneously strained rocks, with petrophysical properties differing from the host rock. Here we present a synthetic workflow to evaluate the potential of seismic data for imaging fault structure and properties. The workflow consists of discrete element modeling (DEM) of faulting, empirical relations to modify initial acoustic properties based on volumetric strain, and a ray-based algorithm simulating prestack depth migration (PSDM). We illustrate the application of the workflow in 2D to a 100 m displacement normal fault in a kilometer size sandstone-shale sequence at 1.5 km depth. To explore the effect of particle size on fault evolution, we ran two DEM simulations with particle assemblages of similar bulk mechanical behavior but different particle size, one with coarse (1–3 m particle radii) and the other with fine (0.5–1.5 m particle radii) particles. Both simulations produce realistic but different fault geometries and strain fields, with the finer particle size model displaying narrower fault zones and fault linkage at later stages. Seismic images of these models are highly influenced by illumination direction and wave frequency. Specular illumination highlights flat reflectors outside the fault zone, but fault related diffractions are still observable. Footwall directed illumination produces low amplitude images. Hanging wall directed illumination images the shale layers within the main fault segment and the lateral extent of fault related deformation. Resolution and the accuracy of the reflectors are proportional to wave frequency. Wave frequencies of 20 Hz or more are necessary to image the different fault structure of the coarse and fine models. At 30–40 Hz, there is a direct correlation between seismic amplitude variations and the input acoustic properties after faulting. At these high frequencies, seismic amplitude variations predict both the extent of faulting and the changes in rock properties in the fault zone.

Charlotte Botter; Nestor Cardozo; Stuart Hardy; Isabelle Lecomte; Alejandro Escalona

2014-01-01T23:59:59.000Z

282

Probing the mass loss history of carbon stars using CO line and dust continuum emission  

E-Print Network [OSTI]

An extensive modelling of CO line emission from the circumstellar envelopes around a number of carbon stars is performed. By combining radio observations and infrared observations obtained by ISO the circumstellar envelope characteristics are probed over a large radial range. In the radiative transfer analysis the observational data are consistently reproduced assuming a spherically symmetric and smooth wind expanding at a constant velocity. The combined data set gives better determined envelope parameters, and puts constraints on the mass loss history of these carbon stars. The importance of dust in the excitation of CO is addressed using a radiative transfer analysis of the observed continuum emission, and it is found to have only minor effects on the derived line intensities. The analysis of the dust emission also puts further constraints on the mass loss rate history. The stars presented here are not likely to have experienced any drastic long-term mass loss rate modulations, at least less than a factor of about 5, over the past thousands of years. Only three, out of nine, carbon stars were observed long enough by ISO to allow a detection of CO far-infrared rotational lines.

F. L. Schoeier; N. Ryde; H. Olofsson

2002-06-05T23:59:59.000Z

283

Computational mechanics  

SciTech Connect (OSTI)

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.

Goudreau, G.L.

1993-03-01T23:59:59.000Z

284

Connecting the molecular scale to the continuum scale for diffusion processes in smectite-rich porous media  

SciTech Connect (OSTI)

In this paper, we address the manner in which the continuum-scale diffusive properties of smectite-rich porous media arise from their molecular- and pore-scale features. Our starting point is a successful model of the continuum-scale apparent diffusion coefficient for water tracers and cations which decomposes it as a sum of pore-scale terms describing diffusion in macropore and interlayer 'compartments.' We then apply molecular dynamics (MD) simulations to determine molecular-scale diffusion coefficients D{sub interlayer} of water tracers and representative cations (Na{sup +}, Cs{sup +}, Sr{sup 2+}) in Na-smectite interlayers. We find that a remarkably simple expression relates D{sub interlayer} to the pore-scale parameter {delta}{sub nanopore} {<=} 1, a constrictivity factor that accounts for the lower mobility in interlayers as compared to macropores: {delta}{sub nanopore} = D{sub interlayer}/D{sub 0}, where D{sub 0} is the diffusion coefficient in bulk liquid water. Using this scaling expression, we can accurately predict the apparent diffusion coefficients of tracer H{sub 2}O, Na{sup +}, Sr{sup 2+} and Cs{sup +}+ in compacted Na-smectite-rich materials.

Bourg, I.C.; Sposito, G.

2009-12-01T23:59:59.000Z

285

Beta relaxation in the shear mechanics of equilibrium viscous liquids: Phenomenology and network modeling of the alpha-beta merging region  

E-Print Network [OSTI]

The phenomenology of the beta relaxation process in the shear-mechanical response of glass-forming liquids is summarized and compared to that of the dielectric beta process. Furthermore, we discuss how to model the observations by means of standard viscoelastic modeling elements. Necessary physical requirements to such a model are outlined, and it is argued that physically relevant models must be additive in the shear compliance of the alpha and beta parts. A model based on these considerations is proposed and fitted to data for Polyisobutylene 680.

Bo Jakobsen; Kristine Niss; Claudio Maggi; Niels Boye Olsen; Tage Christensen; Jeppe C. Dyre

2010-05-26T23:59:59.000Z

286

Gradient Plasticity Model and its Implementation into MARMOT  

SciTech Connect (OSTI)

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.

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

2013-08-01T23:59:59.000Z

287

Magnetic hysteresis in two model spin systems  

Science Journals Connector (OSTI)

A systematic study of hysteresis in model continuum and lattice spin systems is undertaken by constructing a statistical-mechanical theory wherein spatial fluctuations of the order parameter are incorporated. The theory is used to study the shapes and areas of the hysteresis loops as functions of the amplitude (H0) and frequency (?) of the magnetic field. The response of the spin systems to a pulsed magnetic field is also studied. The continuum model that we study is a three-dimensional (?2)2 model with O(N) symmetry in the large-N limit. The dynamics of this model are specified by a Langevin equation. We find that the area A of the hysteresis loop scales as A?H00.66?0.33 for low values of the amplitude and frequency of the magnetic field. The hysteretic response of a two-dimensional, nearest-neighbor, ferromagnetic Ising model is studied by a Monte Carlo simulation on 10×10, 20×20, and 50×50 lattices. The framework that we develop is compared with other theories of hysteresis. The relevance of these results to hysteresis in real magnets is discussed.

Madan Rao; H. R. Krishnamurthy; Rahul Pandit

1990-07-01T23:59:59.000Z

288

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

SciTech Connect (OSTI)

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.

Bridge, Carrie R.; Siana, Brian; Salvato, Mara; Rudie, Gwen C. [California Institute of Technology, 220-6, Pasadena, CA 91125 (United States); Teplitz, Harry I. [Infrared Processing and Analysis Center, MS 100-22, Caltech, Pasadena, CA 91125 (United States); Scarlata, Claudia; Colbert, James; Armus, Lee [Science Center, California Institute of Technology, 220-6, Pasadena, CA 91125 (United States); Conselice, Christopher J. [University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Ferguson, Henry C.; Brown, Thomas M.; Giavalisco, Mauro [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); De Mello, Duilia F. [Department of Physics, Catholic University of America, 620 Michigan Avenue, Washington, DC 20064 (United States); Gardner, Jonathan P., E-mail: bridge@astro.caltech.ed [Astrophysics Science Division, Observational Cosmology Laboratory, Code 665, Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2010-09-01T23:59:59.000Z

289

The cost efficiency of Kyoto flexible mechanisms: a top-down study with the GEM-E3 world model  

Science Journals Connector (OSTI)

Among Kyoto flexible mechanisms, emission trading (ET) shows more promise in cost efficiency but less flexibility in practice than Joint Implementation (JI) and the Clean Development Mechanism (CDM). The problem draws our attention to whether JI and ... Keywords: C68, Clean Development Mechanisms, Cost efficiency, Emission trading, Joint Implementation, Q43, Q48

Haoran Pan

2005-11-01T23:59:59.000Z

290

Mechanics of the power stroke in myosin II  

Science Journals Connector (OSTI)

Power stroke in skeletal muscles is a result of a conformational change in the globular portion of the molecular motor myosin II. In this paper we show that the fast tension recovery data reflecting the inner working of the power stroke mechanism can be quantitatively reproduced by a Langevin dynamics of a simple mechanical system with only two structural states. The proposed model is a generalization of the two state model of Huxley and Simmons. The main idea is to replace the rigid bistable device of Huxley and Simmons with an elastic bistable snap spring. In this setting the attached configuration of a cross bridge is represented not only by the discrete energy minima but also by a continuum of intermediate states where the fluctuation induced dynamics of the system takes place. We show that such soft-spin approach explains the load dependence of the power stroke amplitude and removes the well-known contradiction inside the conventional two state model regarding the time scale of the power stroke.

L. Marcucci and L. Truskinovsky

2010-05-13T23:59:59.000Z

291

Development of Reduced Combustion Mechanisms for Premixed Flame Modeling in Steam Cracking Furnaces with Emphasis on NO Emission  

Science Journals Connector (OSTI)

A systematic reduction of the detailed combustion chemistry based on the application of quasi steady state (QSS) approximation for some species leads to several reduced mechanisms (7- to 12-step) for a hydrocarbon?hydrogen fuel with a composition representative for industrial steam cracking furnaces. ... The basis for the construction of all reduced mechanisms is a skeletal mechanism obtained from the detailed GRI-Mech 3.0 and consisting of 223 elementary reaction steps. ... for the near-ignition state based on both mechanisms identified the deficiencies of the 1998-mechanism, in particular, the specifics of the low-temp. ...

G. D. Stefanidis; G. J. Heynderickx; G. B. Marin

2005-10-29T23:59:59.000Z

292

A general mechanism for producing scale-invariant perturbations and small non-Gaussianity in ekpyrotic models  

E-Print Network [OSTI]

We explore a new type of entropic mechanism for generating density perturbations in a contracting phase in which there are two scalar fields, but only one has a steep negative potential. This first field dominates the energy density and is the source of the ekpyrotic equation of state. The second field has a negligible potential, but its kinetic energy density is coupled to the first field with a non-linear sigma-model type interaction. We show that for any ekpyrotic equation of state it is possible to choose the potential and the kinetic coupling such that exactly scale-invariant (or nearly scale-invariant) entropy perturbations are produced. The corresponding background solutions are stable, and the bispectrum of the entropy perturbations vanishes as no non-Gaussianity is produced during the ekpyrotic phase. Hence, the only contribution to non-Gaussianity comes from the non-linearity of the conversion process during which entropic perturbations are turned into adiabatic ones, resulting in a local non-Gaussianity parameter $f_{NL} \\sim 5$.

Anna Ijjas; Jean-Luc Lehners; Paul J. Steinhardt

2014-06-06T23:59:59.000Z

293

Mechanism of methanol synthesis on Cu(100) and Zn/Cu(100) surfaces: Comparative dipped adcluster model study  

SciTech Connect (OSTI)

The mechanism of methanol synthesis from CO{sub 2} and H{sub 2} on Cu(100) and Zn/Cu(100) surfaces was studied using the dipped adcluster model (DAM) combined with ab initio Hartree-Fock (HF) and second-order Moeller-Plesset (MP2) calculations. On clean Cu(100) surface, calculations show that five successive hydrogenations are involved in the hydrogenation of adsorbed CO{sub 2} to methanol, and the intermediates are formate, dioxomethylene, formaldehyde, and methoxy. The rate-limiting step is the hydrogenation of formate to formaldehyde, and the Cu-Cu site is responsible for the reaction on Cu(100). The roles of Zn on Zn/Cu(100) catalyst are to modify the rate-limiting step of the reaction: to lower the activation energies of this step and to stabilize the dioxomethylene intermediate at the Cu-Zn site. The present comparative results indicate that the Cu-Zn site is the active site, which cooperates with the Cu-Cu site to catalyze methanol synthesis on a Cu-based catalyst. Electron transfer from surface to adsorbates is the most important factor in affecting the reactivity of these surface catalysts.

Nakatsuji, Hiroshi; Hu, Zhenming

2000-03-05T23:59:59.000Z

294

The Two-Dimensional Ising Model  

Science Journals Connector (OSTI)

The two-dimensional Ising model is probably one of the most ... bosonic field theory, made of two independent Ising models. In this bosonic formulation, the ... we also present the solution of the continuum Ising

Philippe Di Francesco; Pierre Mathieu; David Sénéchal

1997-01-01T23:59:59.000Z

295

NREL: Continuum Magazine - Computing Advances Enable More Efficient...  

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

model of a building and then analyze its energy performance. OpenStudio works with SketchUp, a 3-D drawing tool that architects often use to design buildings. Linking the two...

296

The sources of extended continuum emission towards Q0151+048A : The host galaxy and the Damped Ly-alpha Absorber  

E-Print Network [OSTI]

We present deep imaging in the U, B and I bands obtained under excellent seeing conditions of the double quasar Q0151+048A,B and of the Damped Ly-alpha (DLA) absorbing galaxy at z(abs) = 1.9342 named S4. We analyse the data employing two separate and independent methods. First we deconvolve the images using the MCS algorithm, secondly we decompose the images via an object based iteration process where we fit models to objects without any attempt to improve the resolution of the data. Our detailed analysis of the images reveals, somewhat surprisingly, that extended objects centred on the quasars themselves are much brighter continuum sources than the DLA galaxy. Due to the complexity caused by the many superimposed objects, we are unable to certify whether or not continuum emission from the DLA galaxy is detected. Continuum emission from the extended objects centred on the positions of the quasars is clearly seen, and the objects are tentatively identified as the ``host galaxies'' of the quasars. The flux of those host galaxies is of order 2--6% of the quasar flux, and the light profile of the brighter of the two is clearly best fit with a de Vaucouleurs profile. We discuss two alternative interpretations of the origin of the extended flux: i) the early stage of a massive elliptical galaxy in the process of forming the bulk of its stars, and ii) quasar light scattered by dust.

J. U. Fynbo; I. Burud; P. Moller

2000-04-06T23:59:59.000Z

297

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)

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.

NONE

1998-09-01T23:59:59.000Z

298

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

SciTech Connect (OSTI)

The electron-atom neutral bremsstrahlung continuum radiation emitted from weakly ionized plasmas is investigated for electron density and temperature diagnostics. The continuum spectrum in 450–1000?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 280–450?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.

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)

2014-02-24T23:59:59.000Z

299

Sustainable Transportation, Continuum Magazine, Fall 2013 / Issue 5 (Book), NREL (National Renewable Energy Laboratory)  

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

L L L 2 0 1 3 / I S S U E 5 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 S U S T A I N A B L E T R A N S P O R T A T I O N 2 Continuum DAN SAYS TRANSFORMING TRANSPORTATION This issue of Continuum focuses on our contributions toward creating a sustainable transportation system-from developing more efficient electric and hydrogen fuel-cell vehicles to inventing technologies and processes for producing biofuel alternatives to gasoline, diesel, and even jet fuel. In some ways, the challenges we face in transforming our nation's vehicle

300

ME346A Introduction to Statistical Mechanics Wei Cai Stanford University Win 2011 Handout 12. Ising Model  

E-Print Network [OSTI]

. Ising Model February 25, 2011 Contents 1 Definition of Ising model 2 2 Solving the 1D Ising model 4 2.1 Non-interacting model (J = 0) . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 Ising model = 0) . . . . . . . . . . . . . . . . . . . . . . . . . 7 3 Generalized 1D Ising model 11 3.1 Spins

Cai, Wei

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

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  

Broader source: Energy.gov [DOE]

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 through Natural Isotopic Reactive Tracers and Geochemical Investigation presentation at the April 2013 peer review meeting held in Denver, Colorado.

302

Understanding open source software peer review: Review processes, parameters and statistical models, and underlying behaviours and mechanisms.  

E-Print Network [OSTI]

??Peer review is seen as an important quality assurance mechanism in both industrial development and the open source software (OSS) community. The techniques for performing… (more)

Rigby, Peter C

2011-01-01T23:59:59.000Z

303

Antiradical Power of Carotenoids and Vitamin E: Testing the Hydrogen Atom Transfer Mechanism  

Science Journals Connector (OSTI)

Solvent effects were included, using the polarizable continuum model (PCM),(46, 47) with water and benzene acting as the solvents for polar and nonpolar environments, respectively. ... Antiradical Power of CAR ... The electrodonating (?–) and electroaccepting (?+) powers of the most relevant ... ...

Ana Martínez; Andrés Barbosa

2008-12-04T23:59:59.000Z

304

Quantum Mechanics associated with a Finite Group  

E-Print Network [OSTI]

I describe, in the simplified context of finite groups and their representations, a mathematical model for a physical system that contains both its quantum and classical aspects. The physically observable system is associated with the space containing elements fxf for f an element in the regular representation of a given finite group G. The Hermitian portion of fxf is the Wigner distribution of f whose convolution with a test function leads to a mathematical description of the quantum measurement process. Starting with the Jacobi group that is formed from the semidirect product of the Heisenberg group with its automorphism group SL(2,F{N}) for N an odd prime number I show that the classical phase space is the first order term in a series of subspaces of the Hermitian portion of fxf that are stable under SL(2,F{N}). I define a derivative that is analogous to a pseudodifferential operator to enable a treatment that parallels the continuum case. I give a new derivation of the Schrodinger-Weil representation of the Jacobi group. Keywords: quantum mechanics, finite group, metaplectic. PACS: 03.65.Fd; 02.10.De; 03.65.Ta.

Robert W. Johnson

2006-04-20T23:59:59.000Z

305

nrel.gov/continuum Issue 3 Driving Solar Innovations from  

E-Print Network [OSTI]

achieve production-ready products and manufacturing processes. This "market-relevant" research required-farm computer modeling, to inventing a more efficient air conditioning system and helping a tornado-ravaged town for private industry by reducing risk and encouraging private investment in promising new products

306

Terahertz photometer to observe solar flares in continuum  

E-Print Network [OSTI]

Solar observations at sub-THz frequencies detected a new flare spectral component peaking in the THz range, simultaneously with the well known microwaves component, bringing challenging constraints for interpretation. Higher THz frequencies observations are needed to understand the nature of the mechanisms occurring in flares. A THz photometer system was developed to observe outside the terrestrial atmosphere on stratospheric balloons or satellites, or at exceptionally transparent ground stations. The telescope was designed to observe the whole solar disk detecting small relative changes in input temperature caused by flares at localized positions. A Golay cell detector is preceded by low-pass filters to suppress visible and near IR radiation, a band-pass filter, and a chopper. A prototype was assembled to demonstrate the new concept and the system performance. It can detect temperature variations smaller than 1 K for data sampled at a rate of 10/second, smoothed for intervals larger than 4 seconds. For a 76 ...

Marcon, Rogerio; Fernandes, Luis Olavo T; Godoy, Rodolfo; Marun, Adolfo; Bortolucci, Emilio C; Zakia, Maria Beny; Diniz, José Alexandre; Kudaka, Amauri S

2011-01-01T23:59:59.000Z

307

NREL: Continuum Magazine - Electric Vehicle Battery Development Gains  

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

Electric Vehicle Battery Development Gains Momentum Electric Vehicle Battery Development Gains Momentum Issue 5 Print Version Share this resource Electric Vehicle Battery Development Gains Momentum CAEBAT collaboration targets EDV batteries with longer range and lifespan, at a lower cost. A photo of two men silhouetted in front of six back-lit display screens showing battery models, located in a dark room (22008). Enlarge image NREL's modeling, simulation, and testing activities include battery safety assessment, next-generation battery technologies, material synthesis and research, subsystem analysis, and battery second use studies. Photo by Dennis Schroeder, NREL "When people get behind the wheel of an electric car, it should be a great driving experience. Period." Dr. Taeyoung Han, GM technical fellow, said,

308

Rapid, automated imaging of mouse articular cartilage by microCT for early detection of osteoarthritis and finite element modelling of joint mechanics  

Science Journals Connector (OSTI)

SummaryObjective Mouse articular cartilage (AC) is mostly assessed by histopathology and its mechanics is poorly characterised. In this study: (1) we developed non-destructive imaging for quantitative assessment of AC morphology and (2) evaluated the mechanical implications of AC structural changes. Methods Knee joints obtained from naïve mice and from mice with osteoarthritis (OA) induced by destabilization of medial meniscus (DMM) for 4 and 12 weeks, were imaged by phosphotungstic acid (PTA) contrast enhanced micro-computed tomography (PTA-CT) and scored by conventional histopathology. Our software (Matlab) automatically segmented tibial AC, drew two regions centred on each tibial condyle and evaluated the volumes included. A finite element (FE) model of the whole mouse joint was implemented to evaluate AC mechanics. Results Our method achieved rapid, automated analysis of mouse AC (structural parameters in simulations estimated that AC thinning at early-stages in the DMM model (4 weeks) increases contact pressures (+39%) and Tresca stresses (+43%) in AC. Conclusion PTA-CT imaging is a fast and simple method to assess OA in murine models. Once applied more extensively to confirm its robustness, our approach will be useful for rapidly phenotyping genetically modified mice used for OA research and to improve the current understanding of mouse cartilage mechanics.

P. Das Neves Borges; A.E. Forte; T.L. Vincent; D. Dini; M. Marenzana

2014-01-01T23:59:59.000Z

309

Model system for classical fluids out of equilibrium  

Science Journals Connector (OSTI)

A model system for classical fluids out of equilibrium, referred to as a dissipative particles dynamics (DPD) solid, is studied by analytical and simulation methods. The time evolution of a DPD particle is described by a fluctuating heat equation. This DPD solid with transport based on collisional transfer (high-density mechanism) is complementary to the Lorentz gas with only kinetic transport (low-density mechanism). Combination of both models covers the qualitative behavior of transport properties of classical fluids over the full-density range. The heat diffusivity is calculated using a mean-field theory, leading to a linear-density dependence of this transport coefficient, which is exact at high densities. Subleading density corrections are obtained as well. At lower densities the model has a conductivity threshold below which heat conduction is absent. The observed threshold is explained in terms of percolation diffusion on a random proximity network. The geometrical structure of this network is the same as in continuum percolation of completely overlapping spheres, but the dynamics on this network differs from continuum percolation diffusion. Furthermore, the kinetic theory for DPD is extended to the generalized hydrodynamic regime, where the wave-number-dependent decay rates of the Fourier modes of the energy and temperature fields are calculated.

M. Ripoll and M. H. Ernst

2005-04-12T23:59:59.000Z

310

Time Scales and Mechanisms of Relaxation in the Energy Landscape of Polymer Glass under Deformation: Direct Atomistic Modeling  

Science Journals Connector (OSTI)

Molecular-dynamics simulation is used to explore the influence of thermal and mechanical history of typical glassy polymers on their deformation. Polymer stress-strain and energy-strain developments have been followed for different deformation velocities, also in closed extension-recompression loops. The latter simulate for the first time the experimentally observed mechanical rejuvenation and overaging of polymers, and energy partitioning reveals essential differences between mechanical and thermal rejuvenation. All results can be qualitatively interpreted by considering the ratios of the relevant time scales: for cooling down, for deformation, and for segmental relaxation.

Alexey V. Lyulin and M. A. J. Michels

2007-08-24T23:59:59.000Z

311

ccsd-00001253(version1):8Mar2004 The exploration process of inhomogeneous continuum  

E-Print Network [OSTI]

ccsd-00001253(version1):8Mar2004 The exploration process of inhomogeneous continuum random trees trees. We give a description of the exploration process, a function defined on [0, 1] that encodes increments, exploration process, L´evy process, weak convergence. Mathematics Subject Classification: 60C05

Paris-Sud XI, Université de

312

Non-Orthogonality Problem in Continuum RPA Studied by Orthogonality Condition  

Science Journals Connector (OSTI)

......Introduction In investigation of nuclear excitations triggered...with relatively large energy transfer, one finds...continuum. In an infinite nuclear matter, it is not so...to the single particle energy of particle using a schematic...by Research Center for Nuclear Physics, Osaka University......

Ken Kawahigashi; Munetake Ichimura

1991-04-01T23:59:59.000Z

313

Terahertz atmospheric attenuation and continuum effects David M. Slocum,*a  

E-Print Network [OSTI]

Terahertz atmospheric attenuation and continuum effects David M. Slocum,*a Thomas M. Goyette such as pollution monitoring and detection of energetic chemicals are of particular interest. Although there has been much attention to atmospheric effects over narrow frequency windows, accurate measurements across

Massachusetts at Lowell, University of

314

Initial Tests for an Analog Continuum Correlator for CMB Interferometry Huan T. Tran  

E-Print Network [OSTI]

: Lyman Page Abstract We are proposing to build a high frequency interferometer to study the CMB;2 Initial Tests for an Analog Continuum Correlator for CMB Interferometry Huan T. Tran Abstract We-15) and work below 35 GHz and hence rely heavily on HEMT technology. We are in the initial planning stages

315

AMEAerospace & Mechanical  

E-Print Network [OSTI]

AMEAerospace & Mechanical Engineering #12;Aerospace and Mechanical Engineers design complex mechanical, thermal, fluidic, acousti- cal, optical, and electronic systems, with char- acteristic sizes space. Aerospace and Mechanical Engineering (AME) students conduct basic and applied research within

Wang, Hai

316

The Magnetic Noise of a DC Electric Motor — Modeling of Three-Times-Coupled Electromagnetic, Mechanical and Acoustic Phenomena  

Science Journals Connector (OSTI)

The sound power level of the magnetic noise radiated from a DC electric motor was numerically estimated for different loading conditions and two motor designs. Since the mechanism of the magnetic noise generation...

M. Furlan; M. Boltežar

2005-01-01T23:59:59.000Z

317

A Model for the Nonlinear Mechanical Behavior of Asphalt Binders and its Application in Prediction of Rutting Susceptibility  

E-Print Network [OSTI]

The mechanical behavior of asphalt binders is nonlinear. The binders exhibit shear thinning/thickening behavior in steady shear tests and non-proportational behavior in other standard viscoelastic tests such as creep-recovery or stress relaxation...

Srinivasa Parthasarathy, Atul

2013-04-30T23:59:59.000Z

318

CONTINUUM CONTRIBUTIONS TO THE SDO/AIA PASSBANDS DURING SOLAR FLARES  

SciTech Connect (OSTI)

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 Å, 131 Å, 193 Å, and 335 Å passbands throughout the main phase of the flare was due to free-free emission. Reliable measurements could not be made for the 171 Å channel, while the continuum contribution to the 304 Å channel was negligible due to the presence of the strong He II emission line. Up to 50% of the emission in the 211 Å 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 Å and 211 Å 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.

Milligan, Ryan O.; McElroy, Sarah A., E-mail: r.milligan@qub.ac.uk [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN (United Kingdom)

2013-11-01T23:59:59.000Z

319

Programmable Mechanical Metamaterials  

E-Print Network [OSTI]

We create mechanical metamaterials whose response to uniaxial compression can be programmed by lateral confinement, allowing monotonic, non-monotonic and hysteretic behavior. These functionalities arise from a broken rotational symmetry which causes highly nonlinear coupling of deformations along the two primary axes of these metamaterials. We introduce a soft mechanism model which captures the programmable mechanics, and outline a general design strategy for confined mechanical metamaterials. Finally, we show how inhomogeneous confinement can be explored to create multi stability and giant hysteresis.

Bastiaan Florijn; Corentin Coulais; Martin van Hecke

2014-07-17T23:59:59.000Z

320

Generalized spin systems and ? models  

Science Journals Connector (OSTI)

A generalization of the SU(2) spin systems on a lattice and their continuum limit to an arbitrary compact group G is discussed. The continuum limits are, in general, nonrelativistic ?-model-type field theories targeted on a homogeneous space G/H, where H contains the maximal torus of G. In the ferromagnetic case the equations of motion derived from our continuum Lagrangian generalize the Landau-Lifshitz equations with quadratic dispersion relation for small wave vectors. In the antiferromagnetic case the dispersion law is always linear in the long-wavelength limit. The models become relativistic only when G/H is a symmetric space. Also discussed are a generalization of the Holstein-Primakoff representation of the SU(N) algebra, the topological term, and the existence of the instanton-type solutions in the continuum limit of the antiferromagnetic systems.

S. Randjbar-Daemi; Abdus Salam; J. Strathdee

1993-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Connecting fractional anisotropy from medical images with mechanical anisotropy of a hyperviscoelastic fibre-reinforced constitutive model for brain tissue  

Science Journals Connector (OSTI)

...fibre-reinforced constitutive model for brain tissue Chiara Giordano Svein Kleiven e-mail...Technology-KTH, , Huddinge 141 52, Sweden Brain tissue modelling has been an active area of research for years. Brain matter does not follow the constitutive...

2014-01-01T23:59:59.000Z

322

Modelling of thermo-mechanical and irradiation behavior of metallic and oxide fuels for sodium fast reactors  

E-Print Network [OSTI]

A robust and reliable code to model the irradiation behavior of metal and oxide fuels in sodium cooled fast reactors is developed. Modeling capability was enhanced by adopting a non-empirical mechanistic approach to the ...

Karahan, Aydin

2009-01-01T23:59:59.000Z

323

Discrete element modeling of rock deformation, fracture network development and permeability evolution under hydraulic stimulation  

SciTech Connect (OSTI)

Key challenges associated with the EGS reservoir development include the ability to reliably predict hydraulic fracturing and the deformation of natural fractures as well as estimating permeability evolution of the fracture network with time. We have developed a physics-based rock deformation and fracture propagation simulator by coupling a discrete element model (DEM) for fracturing with a network flow model. In DEM model, solid rock is represented by a network of discrete elements (often referred as particles) connected by various types of mechanical bonds such as springs, elastic beams or bonds that have more complex properties (such as stress-dependent elastic constants). Fracturing is represented explicitly as broken bonds (microcracks), which form and coalesce into macroscopic fractures when external and internal load is applied. The natural fractures are represented by a series of connected line segments. Mechanical bonds that intersect with such line segments are removed from the DEM model. A network flow model using conjugate lattice to the DEM network is developed and coupled with the DEM. The fluid pressure gradient exerts forces on individual elements of the DEM network, which therefore deforms the mechanical bonds and breaks them if the deformation reaches a prescribed threshold value. Such deformation/fracturing in turn changes the permeability of the flow network, which again changes the evolution of fluid pressure, intimately coupling the two processes. The intimate coupling between fracturing/deformation of fracture networks and fluid flow makes the meso-scale DEM- network flow simulations necessary in order to accurately evaluate the permeability evolution, as these methods have substantial advantages over conventional continuum mechanical models of elastic rock deformation. The challenges that must be overcome to simulate EGS reservoir stimulation, preliminary results, progress to date and near future research directions and opportunities will be discussed. Methodology for coupling the DEM model with continuum flow and heat transport models will also be discussed.

Shouchun Deng; Robert Podgorney; Hai Huang

2011-02-01T23:59:59.000Z

324

The three-nucleon continuum: achievements, challenges and applications  

Science Journals Connector (OSTI)

After a brief historic overview the basic equations for three-nucleon (3N) scattering based on general two-nucleon and 3N forces are reviewed and the main steps for their derivation are given. Also the expressions for the various observables, elastic and breakup cross sections, as well as the great variety of spin observables are displayed and derived. The treatment of the 3N Faddeev equations in momentum space and in a partial wave decomposition is outlaid in some detail, the handling of the singularities in the integral kernel described and the algorithms and techniques used to solve the large set of equations in the discretized form are presented. Accuracy tests in form of benchmark calculations, where our results are compared to the ones of other techniques, are given. The bulk part of this review, however, is devoted to the comparison of very many observables in elastic nucleon-deuteron (Nd) scattering and the breakup process to the predictions based on the most modern nucleon-nucleon (NN) forces AV18, Nijmegen93, Nijmegen I and II and a recently updated OBE-potential CD Bonn. Overall the agreement with the data is excellent and there is little room left for the action of a three-nucleon force (3NF). The effects of the ?-?, ?-? and ?-? exchange 3NF's of the Tucson-Melbourne model are studied. They are in general small and in the few cases where discrepancies to data occur using NN forces only, they go into the wrong direction. We propose quite a few measurements, which should help to get more information on the potential energy of three nucleons. Several special topics are discussed: Do certain 3N scattering observables scale with the triton binding energy? Which of the 3N breakup cross sections are totally insensitive to the choice of the NN force and which are very sensitive? How well can one extract the nn scattering length from the 3N breakup? We discuss the outsticking discrepancy of the 3N analyzing power Ay in low energy elastic Nd scattering; the eigen phase shifts and mixing parameters in elastic nd scattering; the simplifications of 3N scattering at high energies and the formulation of the optical potential for elastic nd scattering and its limiting form at high energies. Alternative approaches to solve 3N scattering: in configuration space, using finite rank expansions of NN forces, variational techniques and the hybrid Sendai method are briefly described as well as the proton proton Coulomb force problem in the pd system and the question how to incorporate relativity. Finally some applications are sketched where a 3N final state occurs and where the interaction among the nucleons requires a correct treatment. We mention inelastic electron scattering as well as ?-absorption on 3He (3H) and nonmesonic decay of the hypertriton.

W. Glöckle; H. Wita?a; D. Hüber; H. Kamada; J. Golak

1996-01-01T23:59:59.000Z

325

Source mechanisms and focal depths of East African earthquakes using Rayleigh-wave inversion and body-wave modelling  

Science Journals Connector (OSTI)

......the possible origin of such a thermal feature. Acknowledgments I...their implications for the thermal and mechanical properties of...Vlaar, N. J., 1983. Thermal anomalies and magmatism due...RWENZORI ZAMBIA RWENZORI RUWENZORI SUDAN L. TANCAN. N. S . ZAIRE......

Gordon N. Shudofsky

1985-12-01T23:59:59.000Z

326

Geophys. J. Int. (2000) 142, 151161 A damage mechanics model for power-law creep and earthquake  

E-Print Network [OSTI]

applied to constitutive rules for time-dependent subcritical crack growth. In both phases, the individual that transient creep dominates, with 0Crack growth in this stage is stable and decelerating. For a local softening mechanism (positive feedback), mcrack growth is unstable and accelerating. In this case

327

Green's function method for strength function in three-body continuum  

E-Print Network [OSTI]

Practical methods to compute dipole strengths for a three-body system by using a discretized continuum are analyzed. New techniques involving Green's function are developed, either by correcting the tail of the approximate wave function in a direct calculation of the strength function or by using a solution of a driven Schroedinger equation in a summed expression of the strength. They are compared with the complex scaling method and the Lorentz integral transform, also making use of a discretized continuum. Numerical tests are performed with a hyperscalar three-body potential in the hyperspherical-harmonics formalism. They show that the Lorentz integral transform method is less practical than the other methods because of a difficult inverse transform. These other methods provide in general comparable accuracies.

Y. Suzuki; W. Horiuchi; D. Baye

2009-12-10T23:59:59.000Z

328

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

SciTech Connect (OSTI)

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.

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

2010-07-01T23:59:59.000Z

329

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

SciTech Connect (OSTI)

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.

Rozhansky, I. V. [A.F. Ioffe Physical Technical Institute, 194021 St.Petersburg, Russia and Lappeenranta University of Technology, P.O. Box 20, FI-53851, Lappeenranta (Finland); Averkiev, N. S. [A.F. Ioffe Physical Technical Institute, 194021 St.Petersburg (Russian Federation); Lähderanta, E. [Lappeenranta University of Technology, P.O. Box 20, FI-53851, Lappeenranta (Finland)

2013-12-04T23:59:59.000Z

330

Molecular three-continuum approximation for ionization of H{sub 2} by electron impact  

SciTech Connect (OSTI)

A molecular three-continuum-type approximation is developed to study the (e,2e) reaction for H{sub 2} targets. The molecular nature of the target is treated within the framework of a two-effective-center approximation. The correlate motion of the particles in the final channel of the reaction is taken into account by an adequate product of Coulomb functions. Triple differential cross sections are computed. A good agreement with the available experiments is obtained.

Stia, C.R. [Instituto de Fisica Rosario, CONICET-UNR, Avenida Pellegrini 250, 2000 Rosario (Argentina); Fojon, O.A.; Rivarola, R.D. [Instituto de Fisica Rosario, CONICET-UNR, Avenida Pellegrini 250, 2000 Rosario (Argentina); Escuela de Ciencias Exactas y Naturales, Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, 2000 Rosario (Argentina); Weck, P.F. [Instituto de Fisica Rosario, CONICET-UNR, Avenida Pellegrini 250, 2000 Rosario (Argentina); Institut de Physique, Laboratoire de Physique Moleculaire et des Collisions, Universite de Metz, Technopole 2000, 1 Boulevard Arago, 57078 Metz Cedex 3 (France); Hanssen, J.; Joulakian, B. [Institut de Physique, Laboratoire de Physique Moleculaire et des Collisions, Universite de Metz, Technopole 2000, 1 Boulevard Arago, 57078 Metz Cedex 3 (France)

2002-11-01T23:59:59.000Z

331

Chaos, Scaling and Existence of a Continuum Limit in Classical Non-Abelian Lattice Gauge Theory  

E-Print Network [OSTI]

We discuss space-time chaos and scaling properties for classical non-Abelian gauge fields discretized on a spatial lattice. We emphasize that there is a ``no go'' for simulating the original continuum classical gauge fields over a long time span since there is a never ending dynamical cascading towards the ultraviolet. We note that the temporal chaotic properties of the original continuum gauge fields and the lattice gauge system have entirely different scaling properties thereby emphasizing that they are entirely different dynamical systems which have only very little in common. Considered as a statistical system in its own right the lattice gauge system in a situation where it has reached equilibrium comes closest to what could be termed a ``continuum limit'' in the limit of very small energies (weak non-linearities). We discuss the lattice system both in the limit for small energies and in the limit of high energies where we show that there is a saturation of the temporal chaos as a pure lattice artifact. ...

Nielsen, Holger Bech; Rugh, S E; Nielsen, Holger Bech; Rugh, Hans Henrik; Rugh, Svend Erik

1996-01-01T23:59:59.000Z

332

Homotypic clusters of transcription factor binding sites: a model system for understanding the physical mechanics of gene expression  

E-Print Network [OSTI]

architectures influence the physical mechanisms that ultimately lead to transcription. A first step towards developing a more mechanistic view of CRE organization is to dissect common and simple organizational patterns [1]. One of themost common CRE build- ing... ,25,26].With this new technology, it is possible to experimentally test how different TF binding site organizations influ- ence gene expression. Even with the development of techniques to synthesize DNA more efficiently, it is still very difficult to study how...

Ezer, Daphne; Zabet, Nicolae Radu; Adryan, Boris

2014-08-01T23:59:59.000Z

333

A thermo-mechanical large deformation constitutive model for polymers based on material network description: Application to a semi-crystalline polyamide 66  

Science Journals Connector (OSTI)

Abstract A visco-hyperelastic constitutive model, based on an original approach initially developed by (Billon, 2012) and applied to amorphous rubbery polymers for a one-dimensional formalism, was extended in this study to three-dimensional constitutive equations based on a thermodynamic framework. The model was applied to a semi-crystalline polyamide polymer, PA66. The experiments included tension and shear testing coupled with synchronized digital image correlation and infrared measurements device for capturing the time, temperature, and stress state dependence, as well as the complex thermomechanical coupling exhibited by the material under large deformation. A notion of equivalent strain rate (based on the time–temperature principle superposition) was also introduced to show its capability to build master curves and therefore decrease the number of testing needed to build a material database. The model is based on the Edward Vilgis theory (1986) and accounts for chains network reorganization under external loading through the introduction of an evolution equation for the internal state variable, ? ¯ , representing the degree of mobility of entanglement points. The model accounting for the equivalent strain rate notion was calibrated using master curves. The thermomechanical model agreed well with the experimental mechanical and temperature measurements under tension and shear conditions. The approach developed in this study may open a different way to model the polymer behavior.

A. Maurel-Pantel; E. Baquet; J. Bikard; J.L. Bouvard; N. Billon

2015-01-01T23:59:59.000Z

334

A Contribution to the Modeling of Metal Plasticity and Fracture: From Continuum to Discrete Descriptions  

E-Print Network [OSTI]

and corresponding anisotropy parameters used in the unit cell calculations. Coe cients hi (i = L;T; S;TS; SL;LT) represent the diagonal elements of the Voigt representation of anisotropy tensor h, expressed in the frame of material orthotropy, and h is a scalar... invariant of h de ned in equation (2.14). Wider ranges of variation of hTS were also reported. 17 II Ranges of initial microstructural and loading parameters consid- ered in the unit cell calculations. Requires special choice of porosity as discussed...

Keralavarma, Shyam Mohan

2012-02-14T23:59:59.000Z

335

Continuum Model for the Phase Behavior, Microstructure, and Rheology of Unentangled Polymer Nanocomposite Melts  

Science Journals Connector (OSTI)

† Department of Mathematics and Statistics, University of Cyprus, PO Box 20537, 1678 Nicosia, Cyprus ... Equation 9 accounts for the Helmholtz free energy of mixing between polymer chains and nanoparticles and is able to describe (see Appendix A) the phase behavior of the nanocomposite in the sense that it can reproduce the bimodal obtained by Mackay et al.(40) An additional term called the Carnahan–Starling potential describing the nonideal part of the translational entropy of a hard-sphere gas can also been used,(68) but since it does not alter the phase behavior,(40) it will be omitted here. ... According to ref 15, xrel = 8.98 for volume fractions up to ? = 0.2 (please note the typo in their eq 6 where instead of the common logarithm the natural one should have been used). ...

Pavlos S. Stephanou; Vlasis G. Mavrantzas; Georgios C. Georgiou

2014-06-19T23:59:59.000Z

336

Use of Solution-Phase Vibrational Frequencies in Continuum Models for the Free Energy of Solvation  

Science Journals Connector (OSTI)

We find that vibrational contributions to a solute’s free energy are in general insensitive to whether the solute vibrational frequencies are computed in the gas phase or in solution. In most cases, the difference is smaller than the intrinsic error in ...

Raphael F. Ribeiro; Aleksandr V. Marenich; Christopher J. Cramer; Donald G. Truhlar

2011-08-29T23:59:59.000Z

337

Multi-Length Scale-Enriched Continuum-Level Material Model for Kevlar  

E-Print Network [OSTI]

engineering analyses of ballistic/blast impact protective structures made of this type of material do materials and struc- tures. These materials/structures are commonly used in various protective systems whose projectiles (e.g., bullets, mine, IED or turbine fragments, etc.). Development of the aforementioned

Grujicic, Mica

338

Continuum electromechanical modeling of protein-membrane interactions Y. C. Zhou*  

E-Print Network [OSTI]

and topological transformations of membrane are crucial steps in numerous transport and signaling processes of cells, includ- ing cell migration, membrane trafficking, and ion conduc- tance 1­3 . There are various sorting complex required for transport III ESCRT III in- duced membrane budding or protrusion 5

Lu, Benzhuo

339

Hybrid molecular-continuum fluid models: implementation within a general coupling framework  

Science Journals Connector (OSTI)

...2 Centre for Novel Computing, School of Computer Science, The University of ManchesterManchester...research through the RealityGrid grant GR/R67699. Much of the GCF design...Support, Non-U.S. Gov't | Computer Simulation Internet Mathematical...

2005-01-01T23:59:59.000Z

340

An extended thermodynamic model of transient heat conduction at sub-continuum scales  

Science Journals Connector (OSTI)

...that ballistic carriers can be converted...the ballistic energy flux q b. The...half of the carriers at the initial internal energy theta b=0...reflects the conversion of the ballistic internal energy into the diffusive...

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Development and recent evaluation of the MT_CKD model of continuum absorption  

Science Journals Connector (OSTI)

...20] Figure 2. For the US standard atmosphere...U.S. Department of Energy, Office of Science...windows. J. Direct. Energy 2, 151-161. 42 Fulghum...radiative cooling and energy balance. Here, we describe the development and status of the MT_CKD (MlawerTobinCloughKneizysDavies...

2012-01-01T23:59:59.000Z

342

Preferential mode of gas invasion in sediments : grain-scale model of coupled multiphase fluid flow and sediment mechanics  

E-Print Network [OSTI]

We present a discrete element model for simulating, at the grain scale, gas migration in brine-saturated deformable media. We rigorously account for the presence of two fluids in the pore space by incorporating forces on ...

Jain, Antone Kumar

2009-01-01T23:59:59.000Z

343

Hydrolytic ageing of syntactic foams for thermal insulation in deep water: degradation mechanisms and water uptake model  

Science Journals Connector (OSTI)

This paper focuses on a novel syntactic foam formulation based on a model diepoxy-diamine matrix with a controlled architecture, discusses the factors governing the long-term performance of these materials and...

V. Sauvant-Moynot; N. Gimenez; H. Sautereau

2006-07-01T23:59:59.000Z

344

The holographic mapping of the Standard Model onto the black hole horizon, Part I: Abelian vector field, scalar field and BEH Mechanism  

E-Print Network [OSTI]

Interactions between outgoing Hawking particles and ingoing matter are determined by gravitational forces and Standard Model interactions. In particular the gravitational interactions are responsible for the unitarity of the scattering against the horizon, as dictated by the holographic principle, but the Standard Model interactions also contribute, and understanding their effects is an important first step towards a complete understanding of the horizon's dynamics. The relation between in- and outgoing states is described in terms of an operator algebra. In this paper, the first of a series, we describe the algebra induced on the horizon by U(1) vector fields and scalar fields, including the case of an Englert-Brout-Higgs mechanism, and a more careful consideration of the transverse vector field components.

G. 't Hooft

2005-04-25T23:59:59.000Z

345

The effect of football helmet energy absorption mechanisms on the mitigation of cervical spinal injuries: a mathematical model  

E-Print Network [OSTI]

. The variables which are used for the mathematical model are as follows: head Head acceleration [ft/sec ] 2 x totso Torso acceleration [ft/sec ] 2 head Head velocity [ft/sec] x torso Torso velocity [ft/sec] Xl?, d Head displacement [ft] mh?d Head mass [ibm...

Yung, Adelino

1995-01-01T23:59:59.000Z

346

ON THE INTRINSIC CONTINUUM LINEAR POLARIZATION OF CLASSICAL Be STARS: THE EFFECTS OF METALLICITY AND ONE-ARMED DENSITY PERTURBATIONS  

SciTech Connect (OSTI)

We report on the effects of two disk properties on the continuum linear polarization signature of classical Be stars. First, we investigate the effect of including metallicity in computing the thermal structure of the circumstellar gas on the resulting polarimetric Balmer jump. The Balmer jump is a distinguishing feature of the polarization signature in these objects and, as such, can be used as a tool for differentiating classical Be stars from similar H{alpha}-emitters identified through conventional photometric techniques. We find that although low-metallicity environments will have hotter disk temperatures on average, the temperature change alone cannot account for the discrepancy in the frequency of Balmer jumps between low-metallicity and solar-metallicity stellar populations. Second, we investigate the effect of including a global one-armed oscillation in the gas density distribution of the modeled disk. We find that a non-axisymmetric perturbation pattern yields discernible variations in the predicted polarization level. If these density oscillations are present in the inner region of classical Be star disks, the polarimetric variations should produce a periodic signature which can help characterize the dynamical nature of the gas near the star.

Halonen, Robbie J.; Jones, Carol E., E-mail: rhalonen@uwo.ca [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada)

2013-09-15T23:59:59.000Z

347

Studies of the mechanism of thiophene hydrodesulfurization: Conversion of 2,3- and 2,5-dihydrothiophene and model organometallic compounds  

SciTech Connect (OSTI)

Catalytic hydrodesulfurization (HDS), the process by which organically bound sulfur is removed from crude oils, is one of the largest-scale chemical processes practiced in the world. Thiophene is typical of the organosulfur compounds found in petroleum, and considerable effort has been directed toward investigating the mechanism for thiophene hydrodesulfurization. Recently, the authors have reported new kinetic information involving the HDS of thiophene, 2,3- and 2,5- dihydrothiophenes, and tetrahydrothiophene. These studies were performed with both Re/{gamma}-Al{sub 2}O{sub 3} and Mo/{gamma}-Al{sub 2}O{sub 3} catalysts using a flow microreactor system; in particular, rhenium studies provided new information data concerning reaction intermediates. They have also been able to prepare and characterize thiophene-related organometallic compounds which serve as plausible models for bonding and conversion on catalytic surfaces. The combination of these studies has led to new insights concerning alternate mechanistic pathways for thiophene HDS. This comprehensive mechanism, which is based on kinetic studies using model HDS catalysts and on the synthesis and characterization of relevant transition metal complexes, is offered as a plausible route for thiophene HDS.

Sauer, N.N.; Markel, E.J.; Schrader, G.L.; Angelici, R.J. (Iowa State Univ., Ames (USA))

1989-05-01T23:59:59.000Z

348

Chaos, Scaling and Existence of a Continuum Limit in Classical Non-Abelian Lattice Gauge Theory  

E-Print Network [OSTI]

We discuss space-time chaos and scaling properties for classical non-Abelian gauge fields discretized on a spatial lattice. We emphasize that there is a ``no go'' for simulating the original continuum classical gauge fields over a long time span since there is a never ending dynamical cascading towards the ultraviolet. We note that the temporal chaotic properties of the original continuum gauge fields and the lattice gauge system have entirely different scaling properties thereby emphasizing that they are entirely different dynamical systems which have only very little in common. Considered as a statistical system in its own right the lattice gauge system in a situation where it has reached equilibrium comes closest to what could be termed a ``continuum limit'' in the limit of very small energies (weak non-linearities). We discuss the lattice system both in the limit for small energies and in the limit of high energies where we show that there is a saturation of the temporal chaos as a pure lattice artifact. Our discussion focuses not only on the temporal correlations but to a large extent also on the spatial correlations in the lattice system. We argue that various conclusions of physics have been based on monitoring the non-Abelian lattice system in regimes where the fields are correlated over few lattice units only. This is further evidenced by comparison with results for Abelian lattice gauge theory. How the real time simulations of the classical lattice gauge theory may reach contact with the real time evolution of (semi-classical aspects of) the quantum gauge theory (e.g. Q.C.D.) is left as an important question to be further examined.

Holger Bech Nielsen; Hans Henrik Rugh; Svend Erik Rugh

1996-11-18T23:59:59.000Z

349

Chaos, scaling and existence of a continuum limit in classical non-Abelian lattice gauge theory  

SciTech Connect (OSTI)

We discuss space-time chaos and scaling properties for classical non-Abelian gauge fields discretized on a spatial lattice. We emphasize that there is a {open_quote}no go{close_quotes} for simulating the original continuum classical gauge fields over a long time span since there is a never ending dynamical cascading towards the ultraviolet. We note that the temporal chaotic properties of the original continuum gauge fields and the lattice gauge system have entirely different scaling properties thereby emphasizing that they are entirely different dynamical systems which have only very little in common. Considered as a statistical system in its own right the lattice gauge system in a situation where it has reached equilibrium comes closest to what could be termed a {open_quotes}continuum limit{close_quotes} in the limit of very small energies (weak non-linearities). We discuss the lattice system both in the limit for small energies and in the limit of high energies where we show that there is a saturation of the temporal chaos as a pure lattice artifact. Our discussion focuses not only on the temporal correlations but to a large extent also on the spatial correlations in the lattice system. We argue that various conclusions of physics have been based on monitoring the non-Abelian lattice system in regimes where the fields are correlated over few lattice units only. This is further evidenced by comparison with results for Abelian lattice gauge theory. How the real time simulations of the classical lattice gauge theory may reach contact with the real time evolution of (semi-classical aspects of) the quantum gauge theory (e.g. Q.C.D.) is left an important question to be further examined.

Nielsen, H.B. [Niels Bohr Inst., Kobenhavn (Denmark); Rugh, H.H. [Univ. of Warwick, Coventry (United Kingdom); Rugh, S.E. [Los Alamos National Lab., NM (United States)

1996-12-31T23:59:59.000Z

350

Mechanics, mechanisms, and modeling of the chemical mechanical polishing process  

E-Print Network [OSTI]

The ever-increasing demand for high-performance microelectronic devices has motivated the semiconductor industry to design and manufacture Ultra-Large-Scale Integrated (ULSI) circuits with smaller feature size, higher ...

Lai, Jiun-Yu

2001-01-01T23:59:59.000Z

351

Quasielastic electron- and neutrino-nucleus scattering in a continuum random phase approximation approach  

E-Print Network [OSTI]

We present a continuum random phase approximation approach to study electron- and neutrino-nucleus scattering cross sections, in the kinematic region where quasielastic scattering is the dominant process. We show the validity of the formalism by confronting inclusive ($e,e'$) cross sections with the available data. We calculate flux-folded cross sections for charged-current quasielastic antineutrino scattering off $^{12}$C and compare them with the MiniBooNE cross-section measurements. We pay special emphasis to the contribution of low-energy nuclear excitations in the signal of accelerator-based neutrino-oscillation experiments.

V. Pandey; N. Jachowicz; T. Van Cuyck; J. Ryckebusch; M. Martini

2015-01-16T23:59:59.000Z

352

Quasielastic electron- and neutrino-nucleus scattering in a continuum random phase approximation approach  

E-Print Network [OSTI]

We present a continuum random phase approximation approach to study electron- and neutrino-nucleus scattering cross sections, in the kinematic region where quasielastic scattering is the dominant process. We show the validity of the formalism by confronting inclusive ($e,e'$) cross sections with the available data. We calculate flux-folded cross sections for charged-current quasielastic antineutrino scattering off $^{12}$C and compare them with the MiniBooNE cross-section measurements. We pay special emphasis to the contribution of low-energy nuclear excitations in the signal of accelerator-based neutrino-oscillation experiments.

Pandey, V; Van Cuyck, T; Ryckebusch, J; Martini, M

2015-01-01T23:59:59.000Z

353

Evidence for a wide continuum of polymorphs in a-SiO2  

Science Journals Connector (OSTI)

The irradiations of vitreous amorphous silica with subband-gap laser radiation at 248 nm induces reversible-irreversible compaction. The former is consistent with the creation of a wide continuum of densified amorphous silica (a-SiO2) polymorphs whilst the second stage corresponds to the ablation through laser radiation of the damaged a-SiO2. These observations are discussed in terms of conformational structure modifications (i.e., changes in the distribution of planar rings) and stable superficial defect creation.

C. Fiori and R. A. B. Devine

1986-02-15T23:59:59.000Z

354

Nuclear Halos and Drip Lines in Symmetry-Conserving Continuum HFB Theory  

E-Print Network [OSTI]

We review the properties of nuclear halos and nuclear skins in drip line nuclei in the framework of the spherical Hartree-Fock-Bogoliubov theory with continuum effects and projection on good particle number with the Gogny force. We first establish the position of the un-projected HFB drip lines for the two most employed parametrizations of the Gogny force and show that the use of finite-range interactions leads almost always to small-sized halos, even in the least bound nuclei, which is in agreement with most mean-field predictions. We also discuss the size of the neutron skin at the drip line and its relation to neutron asymmetry. The impact of particle-number projection and its conceptual consequences near the drip line are analyzed in detail. In particular, we discuss the role of the chemical potential in a projected theory and the criteria required to define the drip line. We show that including particle number projection can shift the latter, in particular near closed shells. We notice that, as a result, the size of the halo can be increased due to larger pairing correlations. However, combining the most realistic pairing interaction, a proper treatment of the continuum and particle number projection does not permit to reproduce the very large halos observed in very light nuclei.

N. Schunck; J. L. Egido

2008-09-23T23:59:59.000Z

355

Mechanical Engineering Colloquium September 19, 2014  

E-Print Network [OSTI]

Mechanical Engineering Colloquium September 19, 2014 Macdonald Engineering Building (MD) 267 from 11 - 12 pm Professor Harry Dankowicz Department of Mechanical Science and Engineering University of Illinois, Urbana-Champaign Discontinuity-induced Bifurcations in Models of Mechanical Contact, Capillary

Barthelat, Francois

356

A Deep HST Search for Escaping Lyman Continuum Flux at z~1.3: Evidence for an Evolving Ionizing Emissivity  

E-Print Network [OSTI]

We have obtained deep Hubble Space Telescope far-UV images of 15 starburst galaxies at z~1.3 in the GOODS fields to search for escaping Lyman continuum photons. These are the deepest far-UV images m_{AB}=28.7, 3\\sigma, 1" diameter) over this large an area (4.83 arcmin^2) and provide the best escape fraction constraints for any galaxy at any redshift. We do not detect any individual galaxies, with 3\\sigma limits to the Lyman Continuum (~700 \\AA) flux 50--149 times fainter (in f_nu) than the rest-frame UV (1500 \\AA) continuum fluxes. Correcting for the mean IGM attenuation (factor ~2), as well as an intrinsic stellar Lyman Break (~3), these limits translate to relative escape fraction limits of f_{esc,rel}4 and reionization of the intergalactic medium at z>6. [Abridged

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

2010-01-01T23:59:59.000Z

357

MASTER OF SCIENCE MECHANICAL ENGINEERING  

E-Print Network [OSTI]

MASTER OF SCIENCE IN MECHANICAL ENGINEERING 75 DEVELOPMENT OF A MODEL TO PREDICT AND ASSESS SURFACE Master of Science in Mechanical Engineering-December 2000 Advisors: Charles N. Calvano, Department of Mechanical Engineering David W. Byers, Naval Surface Warfare Center-Carderock Division Survivability has

358

Posters Atmospheric Emitted Radiance Interferometer: Status and Water Vapor Continuum Results  

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

9 9 Posters Atmospheric Emitted Radiance Interferometer: Status and Water Vapor Continuum Results H. E. Revercomb, R. O. Knuteson, W. L. Smith, F. A. Best, and R. G. Dedecker University of Wisconsin Madison, Wisconsin H. B. Howell National Oceanic and Atmospheric Administration Systems Design and Applications Branch Madison, Wisconsin Introduction Accurate and spectrally detailed observations of the thermal emission from radiatively important atmospheric gases, aerosols, and clouds are now being provided to the Atmospheric Radiation Measurement (ARM) data base by the Atmospheric Emitted Radiance Interferometer (AERI) prototype at the Southern Great Plains Cloud and Radiation Testbed (CART) site. Spectra over the range from 520 to 3000 cm -1 (3 to 19 microns) with a resolution of 0.5 cm

359

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

SciTech Connect (OSTI)

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.

Hougen, J.T. [NIST, Gaithersburg, MD (United States)

1993-12-01T23:59:59.000Z

360

Study of spin-temperature effects using energy-ordered continuum gamma-ray spectroscopy technique  

SciTech Connect (OSTI)

We have investigated a new continuum {gamma}-ray spectroscopy technique which is based on the detection of all emitted {gamma} rays in a 4{pi} detector system, and ordering them according to their energies on an event-by-event basis. The technique allows determination of gamma strength functions, and rotational damping width as a function of spin and temperature. Thus, it opens up the possibility of studying the onset of motional narrowing, order-to-chaos transition, and the mapping of the evolution of nuclear collectivity with a spin and temperature. Application of the technique for preferential entry-state population, exit-channel selection, and feeding of the discrete states via selective pathways will be discussed. 20 refs., 4 figs.

Baktash, C.; Halbert, M.L.; Hensley, D.C.; Johnson, N.R.; Lee, I.Y.; McConnell, J.W.; McGowan, F.K.

1990-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

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

SciTech Connect (OSTI)

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.

Not Available

2014-03-01T23:59:59.000Z

362

Continuum Effects and Three-Nucleon Forces in Neutron-Rich Oxygen Isotopes  

SciTech Connect (OSTI)

We employ interactions from chiral effective field theory and compute binding energies, excited states, and radii for isotopes of oxygen with the coupled-cluster method. Our calculation includes the effects of three-nucleon forces and of the particle continuum, both of which are important for the description of neutron-rich isotopes in the vicinity of the nucleus 24O. Our main results are the placement of the neutron drip-line at 24O, the assignment of spins, parities and resonance widths for several low-lying states of the drip-line nucleus, and an efficient approximation that incorporates the effects of three-body interactions.

Hagen, Gaute [ORNL; Hjorth-Jensen, M. [University of Oslo, Norway; Jansen, G R [University of Oslo, Norway; Machleidt, R [University of Idaho; Papenbrock, T. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)

2012-01-01T23:59:59.000Z

363

Radio-Continuum Emission From The Young Galactic Supernova Remnant G1.9+0.3  

E-Print Network [OSTI]

We present an analysis of a new Australia Telescope Compact Array (ATCA) radio-continuum observation of supernova remnant (SNR) G1.9+0.3, which at an age of $\\sim$181$\\pm$25 years is the youngest known in the Galaxy. We analysed all available radio-continuum observations at 6-cm from the ATCA and the Very Large Array. Using this data we estimate an expansion rate for G1.9+0.3 of 0.563%$\\pm$0.078% per year between 1984 and 2009. We note that in the 1980's G1.9+0.3 expanded somewhat slower (0.484% per year) than more recently (0.641% per year). We estimate that the average spectral index between 20-cm and 6-cm, across the entire SNR is $\\alpha=-0.72\\pm 0.26$ which is typical for younger SNRs. At 6-cm, we detect an average of 6% fractionally polarised radio emission with a peak of 17%$\\pm$3%. The polarised emission follows the contours of the strongest of X-ray emission. Using the new equipartition formula we estimate a magnetic field strength of B$\\approx 273\\mu$G, which to date, is one of the highest magnetic field strength found for any SNR and consistent with G1.9+0.3 being a very young remnant. This magnetic field strength implies a minimum total energy of the synchrotron radiation of E$_{\\textrm{min}} \\approx$ 1.8$\\times$10$^{48}$ ergs.

A. Y. De Horta; M. D. Filipovi?; E. J. Crawford; F. H. Stootman; T. G. Pannuti; L. M. Bozzetto; J. D. Collier; E. R. Sommer; A. R. Kosakowski

2014-08-22T23:59:59.000Z

364

Mechanical memory  

DOE Patents [OSTI]

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.

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

2006-05-16T23:59:59.000Z

365

Mechanical memory  

DOE Patents [OSTI]

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.

Gilkey, Jeffrey C. (Albuquerque, NM); Duesterhaus, Michelle A. (Albuquerque, NM); Peter, Frank J. (Albuquerque, NM); Renn, Rosemarie A. (Alburquerque, NM); Baker, Michael S. (Albuquerque, NM)

2006-08-15T23:59:59.000Z

366

Accepted to SPIE DSS Conference April 29-May 3, 2013, Baltimore, MD Terahertz atmospheric attenuation and continuum effects  

E-Print Network [OSTI]

Terahertz atmospheric attenuation and continuum effects David M. Slocum,*a Thomas M. Goyette,a Elizabeth J interest in the terahertz frequency region. Applications such as pollution monitoring and detection of energetic chemicals are of particular interest. Although there has been much attention to atmospheric

Massachusetts at Lowell, University of

367

Mechanical fault interaction within the Los Angeles Basin: A two-dimensional analysis using mechanical efficiency  

E-Print Network [OSTI]

Mechanical fault interaction within the Los Angeles Basin: A two-dimensional analysis using mechanical efficiency Michele L. Cooke Geosciences Department, University of Massachusetts-Amherst, Amherst July 2002. [1] Mechanical models examine deformation within eight different structural cross sections

Cooke, Michele

368

Ising Model from Intertwiners  

E-Print Network [OSTI]

Spin networks appear in a number of areas, for instance in lattice gauge theories and in quantum gravity. They describe the contraction of intertwiners according to the underlying network. We show that a certain generating function of intertwiner contractions leads to the partition function of the 2d Ising model. This implies that the intertwiner model possesses a second order phase transition, thus leading to a continuum limit with propagating degrees of freedom.

Dittrich, Bianca

2013-01-01T23:59:59.000Z

369

Mechanism of Interaction Between the General Anesthetic Halothane and a Model Ion Channel Protein, I: Structural Investigations via X-Ray Reflectivity from Langmuir Monolayers  

SciTech Connect (OSTI)

We previously reported the synthesis and structural characterization of a model membrane protein comprised of an amphiphilic 4-helix bundle peptide with a hydrophobic domain based on a synthetic ion channel and a hydrophilic domain with designed cavities for binding the general anesthetic halothane. In this work, we synthesized an improved version of this halothane-binding amphiphilic peptide with only a single cavity and an otherwise identical control peptide with no such cavity, and applied x-ray reflectivity to monolayers of these peptides to probe the distribution of halothane along the length of the core of the 4-helix bundle as a function of the concentration of halothane. At the moderate concentrations achieved in this study, approximately three molecules of halothane were found to be localized within a broad symmetric unimodal distribution centered about the designed cavity. At the lowest concentration achieved, of approximately one molecule per bundle, the halothane distribution became narrower and more peaked due to a component of {approx}19Angstroms width centered about the designed cavity. At higher concentrations, approximately six to seven molecules were found to be uniformly distributed along the length of the bundle, corresponding to approximately one molecule per heptad. Monolayers of the control peptide showed only the latter behavior, namely a uniform distribution along the length of the bundle irrespective of the halothane concentration over this range. The results provide insight into the nature of such weak binding when the dissociation constant is in the mM regime, relevant for clinical applications of anesthesia. They also demonstrate the suitability of both the model system and the experimental technique for additional work on the mechanism of general anesthesia, some of it presented in the companion parts II and III under this title.

Strzalka, J.; Liu, J; Tronin, A; Churbanova, I; Johansson, J; Blasie, J

2009-01-01T23:59:59.000Z

370

Thermodynamics and statistical mechanics  

Science Journals Connector (OSTI)

... IN this book, Professor Landsberg brings together thermodynamics and statistical mechanics to provide a coherent account of these interrelated branches of physical theory ... side usually result in the essential structures of both becoming obscured. The value of classical thermodynamics lies in what it can do without invoking microscopic models and it is best learnt ...

C.J. Adkins

1979-12-20T23:59:59.000Z

371

Residential Mechanical Precooling  

SciTech Connect (OSTI)

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.

German, A.; Hoeschele, M.

2014-12-01T23:59:59.000Z

372

Mechanical Vibration  

Science Journals Connector (OSTI)

... THE suppression and control of mechanical vibration have assumed great importance in engineering. One consequence of this is that the number ... degree of emphasis is placed on transient oscillation (in addition to steady-State and free vibration). The treatment of this topic is based mainly on phase-plane constructions and it ...

R. E. D. BISHOP

1958-12-06T23:59:59.000Z

373

Estimation of boron isotope ratios using high resolution continuum source atomic absorption spectrometry  

Science Journals Connector (OSTI)

In the production of 10B enriched steels, the production–recycling process needs to be closely monitored for inadvertent mix-up of materials with different B isotope levels. A quick and simple method for the estimation of boron isotope ratios in high alloyed steels using high resolution continuum source flame AAS (HR-CS-FAAS) was developed. On the 208.9 nm B line the wavelength of the peak absorption of 10B and 11B differs by 2.5 pm. The wavelength of the peak absorption of boron was determined by fitting a Gauss function through spectra simultaneously recorded by HR-CS-FAAS. It was shown that a linear correlation between the wavelength of the peak absorption and the isotope ratio exists and that this correlation is independent of the total boron concentration. Internal spectroscopic standards were used to compensate for monochromator drift and monochromator resolution changes. Accuracy and precision of the analyzed samples were thereby increased by a factor of up to 1.3. Three steel reference materials and one boric acid CRM, each certified for the boron isotope ratio were used to validate the procedure.

Helmar Wiltsche; Karl Prattes; Michael Zischka; Günter Knapp

2009-01-01T23:59:59.000Z

374

Radio Continuum Observations of the Galactic Center: Photoevaporative Proplyd-like Objects near Sgr A*  

E-Print Network [OSTI]

We present radio images within 30$''$ of Sgr A* based on recent VLA observations at 34 GHz with 7.8 microJy sensitivity and resolution $\\sim88\\times46$ milliarcseconds (mas). We report 44 partially resolved compact sources clustered in two regions in the E arm of ionized gas that orbits Sgr A*. These sources have size scales ranging between ~50 and 200 mas (400 to 1600 AUs), and a bow-shock appearance facing the direction of Sgr A*. Unlike the bow-shock sources previously identified in the near-IR but associated with massive stars, these 34 GHz sources do not appear to have near-IR counterparts at 3.8 $\\mu$m. We interpret these sources as a candidate population of photoevaporative protoplanetary disks (proplyds) that are associated with newly formed low mass stars with mass loss rates ~10^{-7} - 10^{-6} solar mass per year and are located at the edge of a molecular cloud outlined by ionized gas. The disks are externally illuminated by strong Lyman continuum radiation from the ~100 OB and WR massive stars dist...

Yusef-Zadeh, F; Wardle, M; Cotton, W; Schödel, R; Royster, M J

2015-01-01T23:59:59.000Z

375

Damping of the continuum response from 2p-2h excitations  

Science Journals Connector (OSTI)

The nuclear response function in the random-phase-approximation theory may be substantially altered at high excitation energy due to coupling of 1p-1h to 2p-2h or higher excitations. In the continuum region of quasi-elastic scattering, this coupling can be included by inserting into the random-phase-approximation Green’s function a complex self-energy for the p-h states, which depends only on their energy, spin (S), and isospin (T). This allows the full response to be expressed directly as an integral over the random-phase-approximation response. The self-energies, which can be determined from empirical single-particle spreading widths, are large in the spin and isospin channels, but small in the T,S=0,0 channel, giving rise to substantial damping in all channels except 0,0. We apply this method to calculate damping of the random-phase-approximation surface response, and discuss the consequences for cross sections and spin observables in quasi-elastic (p,p’) and (n,p) reactions.

R. D. Smith and J. Wambach

1988-07-01T23:59:59.000Z

376

Lattice Boltzmann Methods for thermal flows: continuum limit and applications to compressible Rayleigh-Taylor systems  

E-Print Network [OSTI]

We compute the continuum thermo-hydrodynamical limit of a new formulation of lattice kinetic equations for thermal compressible flows, recently proposed in [Sbragaglia et al., J. Fluid Mech. 628 299 (2009)]. We show that the hydrodynamical manifold is given by the correct compressible Fourier- Navier-Stokes equations for a perfect fluid. We validate the numerical algorithm by means of exact results for transition to convection in Rayleigh-B\\'enard compressible systems and against direct comparison with finite-difference schemes. The method is stable and reliable up to temperature jumps between top and bottom walls of the order of 50% the averaged bulk temperature. We use this method to study Rayleigh-Taylor instability for compressible stratified flows and we determine the growth of the mixing layer at changing Atwood numbers up to At ~ 0.4. We highlight the role played by the adiabatic gradient in stopping the mixing layer growth in presence of high stratification and we quantify the asymmetric growth rate for spikes and bubbles for two dimensional Rayleigh- Taylor systems with resolution up to Lx \\times Lz = 1664 \\times 4400 and with Rayleigh numbers up to Ra ~ 2 \\times 10^10.

Andrea Scagliarini; Luca Biferale; Mauro Sbragaglia; Kazuyasu Sugiyama; Federico Toschi

2010-05-20T23:59:59.000Z

377

High-Resolution Radio Continuum Measurements of the Nuclear Disks of Arp 220  

E-Print Network [OSTI]

We present new Karl G. Jansky Very Large Array radio continuum images of the nuclei of Arp 220, the nearest ultra-luminous infrared galaxy. These images have both the angular resolution to study detailed morphologies of the two nuclei that power the system and sensitivity to a wide range of spatial scales. At 33 GHz, and with a resolution of 0".081 x 0".063 (29.9 x 23.3 pc), we resolve the emission surrounding both nuclei and conclude that is mostly synchrotron in nature. The spatial distributions of radio emission in both nuclei are well described by exponential profiles. These have deconvolved half-light radii of 51 and 35 pc for the eastern and western nuclei, and they match the number density profile of radio supernovae observed with very long baseline interferometry. This similarity might be due to the fast cooling of cosmic rays electrons caused by the presence of a strong (~ mG) magnetic field in this system. We estimate high luminosity surface densities of $\\mathrm{\\Sigma_{IR} \\sim 4.2^{+1.6}_{-0.7} \\...

Barcos-Muñoz, Loreto; Evans, Aaron S; Privon, George C; Armus, Lee; Condon, Jim; Mazzarella, Joseph M; Meier, David S; Momjian, Emmanuel; Murphy, Eric J; Ott, Juerguen; Reichardt, Ashely; Sakamoto, Kazushi; Sanders, David B; Schinnerer, Eva; Stierwalt, Sabrina; Surace, Jason A; Thompson, Todd A; Walter, Fabian

2014-01-01T23:59:59.000Z

378

Mechanics of collective unfolding  

E-Print Network [OSTI]

Mechanically induced unfolding of passive crosslinkers is a fundamental biological phenomenon encountered across the scales from individual macro-molecules to cytoskeletal actin networks. In this paper we study a conceptual model of athermal load-induced unfolding and use a minimalistic setting allowing one to emphasize the role of long-range interactions while maintaining full analytical transparency. Our model can be viewed as a description of a parallel bundle of N bistable units confined between two shared rigid backbones that are loaded through a series spring. We show that the ground states in this model correspond to synchronized, single phase configurations where all individual units are either folded or unfolded. We then study the fine structure of the wiggly energy landscape along the reaction coordinate linking the two coherent states and describing the optimal mechanism of cooperative unfolding. Quite remarkably, our study shows the fundamental difference in the size and structure of the folding-u...

Caruel, M; Truskinovsky, L

2015-01-01T23:59:59.000Z

379

Perturbation-theoretical-model calculation of the lattice mechanics of the NaF and RbF crystals in the Watson potential approximation  

Science Journals Connector (OSTI)

A simplified version of the perturbation-theoretical-model approach to ionic solids developed by Basu and Sengupta has been employed for calculating the different lattice-mechanical properties of the two low-polarizability ionic crystals. Although this is not a microscopic calculation, the interesting feature of the method is that the only input data necessary for predicting the crystal properties are the Hartree-Fock wave functions of the constituent ions. In addition, the present investigation for the first time makes an attempt to study the effect of the alteration of the free-ion wave functions, when the ions are put in a crystal, on the lattice-dynamical properties. The effect of the crystal environment is thought to be simulated by the Watson potential. The calculated properties with and without the potential give a rough estimate of the order of magnitude of this effect. It is found that certain properties, namely, the dielectric properties and some phonons in the symmetry directions that depend on the excited states of the crystal, are rather sensitive to this effect which varies from crystal to crystal. Apart from this, a unified treatment of the cohesion, the phase transition, and the elastic, the dielectric, and the vibrational properties of the NaF and RbF crystals is presented without any adjustable free parameter. In view of the simplicity of the approach, the overall agreement obtained is satisfactory. Finally the reliability and the limitations of the present method of estimating the effect of the surroundings are critically discussed.

D. Bose; A. Ghosh; A. N. Basu

1984-03-15T23:59:59.000Z

380

Constitutive modeling of the finite deformation behavior of membranes possessing a triangulated networked microstructure  

E-Print Network [OSTI]

Many biological, natural and synthetic materials possess a networked or micro-truss-like microstructure. In this thesis work, a general microstructurally-informed continuum level constitutive model of the large stretch ...

Arslan, Melis

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Toward a new paradigm for reactive flow modeling.  

SciTech Connect (OSTI)

Traditional reactive flow modeling provides a computational representation of shock initiation of energetic materials. Most reactive flow models require ad hoc assumptions to obtain robust simulations, assumptions that result from partitioning energy and volume change between constituents in a reactive mixture. For example, most models assume pressure and/or temperature equilibrium for the mixture. Many mechanical insults to energetic materials violate these approximations. Careful analysis is required to ensure that the model assumptions and limitations are not exceeded. One limitation is that the shock to detonation transition is replicated only for strong planar shocks. Many models require different parameters to match data from thin pulse, ramp wave, or multidimensional loading, an approach that fails for complex loading. To accurately simulate reaction under non-planar shock impact scenarios a new formalism is required. The continuum mixture theory developed by Baer and Nunziato is used to eliminate ad hoc assumptions and limitations of current reactive flow models. This modeling paradigm represents the multiphase nature of reacting condensed/gas mixtures. Comparisons between simulations and data are presented.

Schmitt, Robert Gerard

2005-08-01T23:59:59.000Z

382

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)

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 µM. 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.

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

2013-08-14T23:59:59.000Z

383

PUBLICATIONS -ZBIB 1. Ahzi, S., Cherkaoui, Zbib and Zikry. "Solid Mechanics and Its Applications: Multiscale  

E-Print Network [OSTI]

.M., Introduction to Dislocation Dynamics, in: Introduction to and fundamentals of discrete dislocations.A., Dislocation Dynamics. In: Handbook of Materials Modeling. Ed. Sidney Yip, pp. 1097-1114, Springer, 2005. 19 11 in Continuum Scale Simulation of Engineering Materials Fundamentals - Microstructures - Process

384

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

SciTech Connect (OSTI)

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.

Burkett, Michael W [Los Alamos National Laboratory; Clancy, Sean P [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

385

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

SciTech Connect (OSTI)

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.

English, Shawn Allen

2014-09-01T23:59:59.000Z

386

$K \\rightarrow ??$ $?I=3/2$ decay amplitude in the continuum limit  

E-Print Network [OSTI]

We present new results for the amplitude $A_2$ for a kaon to decay into two pions with isospin $I=2$: Re$A_2 = 1.50(4)_\\mathrm{stat}(14)_\\mathrm{syst}\\times 10^{-8}$ GeV; Im$A_2 = -6.99(20)_\\mathrm{stat}(84)_\\mathrm{syst}\\times 10^{-13}$ GeV. These results were obtained from two ensembles generated at physical quark masses (in the isospin limit) with inverse lattice spacings $a^{-1}=1.728(4)$ GeV and $2.358(7)$ GeV. We are therefore able to perform a continuum extrapolation and hence largely to remove the dominant systematic uncertainty from our earlier results, that due to lattice artefacts. The only previous lattice computation of $K\\to\\pi\\pi$ decays at physical kinematics was performed using an ensemble at a single, rather coarse, value of the lattice spacing ($a^{-1}\\simeq 1.37(1)$ GeV). We confirm the observation that there is a significant cancellation between the two dominant contributions to Re$A_2$ which we suggest is an important ingredient in understanding the $\\Delta I=1/2$ rule, Re$A_0$/Re$A_2\\simeq 22.5$, where the subscript denotes the total isospin of the two-pion final state. Our result for $A_2$ implies that the electroweak penguin contribution to $\\epsilon^\\prime/\\epsilon$ is Re($\\epsilon^\\prime/\\epsilon)_\\textrm{EWP}=-(6.6\\pm 1.0)\\times 10^{-4}$.

T. Blum; P. A. Boyle; N. H. Christ; J. Frison; N. Garron; T. Janowski; C. Jung; C. Kelly; C. Lehner; A. Lytle; R. D. Mawhinney; C. T. Sachrajda; A. Soni; H. Yin; D. Zhang

2015-02-01T23:59:59.000Z

387

An autonomy-oriented computing mechanism for modeling the formation of energy distribution networks: crude oil distribution in U.S. and Canada  

Science Journals Connector (OSTI)

An efficient, economical, as well as reliable energy distribution system plays important roles in distributing energy resources from energy suppliers to energy consumers in different regions. In this paper, we present a decentralized self-organized mechanism ...

Benyun Shi; Jiming Liu

2010-09-01T23:59:59.000Z

388

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...

389

Coupled thermal-hydrological-mechanical analyses of the Yucca Mountain Drift Scale Test - Comparison of field measurements to predictions of four different numerical models  

E-Print Network [OSTI]

mechanical analyses of the Yucca Mountain Drift Scale Test –Chemical Responses in the Yucca Mountain Drift Scale Test.Heating Phase of the Yucca Mountain Drift Scale Test. In:

2004-01-01T23:59:59.000Z

390

A Learning Algorithm for Visual Pose Estimation of Continuum Robots Austin Reiter, Roger E. Goldman, Andrea Bajo, Konstantinos Iliopoulos, Nabil Simaan, and Peter K. Allen  

E-Print Network [OSTI]

-Endoscopic Single-Site surgery [3], and Natural Orifice Transluminal Endoscopic Surgery (NOTES) [4]. Continuum of accuracy due to friction, extension and torsion of their actuation lines, shape discrepancy from nominal

Simaan, Nabil

391

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

Office of Environmental Management (EM)

Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Granular Salt Consolidation, Constitutive Model and Micromechanics Coupled Thermal-Hydrological-Mechanical Processes...

392

Heating mechanisms in radio-frequency-driven ultracold plasmas  

Science Journals Connector (OSTI)

Several mechanisms by which an external electromagnetic field influences the temperature of a plasma are studied analytically and specialized to the system of an ultracold plasma (UCP) driven by a uniform radio-frequency (rf) field. Heating through collisional absorption is reviewed and applied to UCPs. Furthermore, it is shown that the rf field modifies the three-body recombination process by ionizing electrons from intermediate high-lying Rydberg states and upshifting the continuum threshold, resulting in a suppression of three-body recombination. Heating through collisionless absorption associated with the finite plasma size is calculated in detail, revealing a temperature threshold below which collisionless absorption is ineffective.

P. W. Smorenburg; L. P. J. Kamp; O. J. Luiten

2012-06-20T23:59:59.000Z

393

Modeling gas flow through microchannels and nanopores Subrata Roya)  

E-Print Network [OSTI]

Modeling gas flow through microchannels and nanopores Subrata Roya) and Reni Raju Computational. A two-dimensional finite-element based microscale flow model is developed to efficiently predict is modeled using either the continuum or the molecular approach.1­4 The con- tinuum approach solves

Roy, Subrata

394

Mechanical & Aerospace Engineering  

E-Print Network [OSTI]

Mechanical & Aerospace Engineering An experimental methodology is presented for mechanism verification of physics-based prognosis of mechanical damage, such as fatigue. The proposed experimental methodology includes multi-resolution in-situ mechanical testing, advanced imaging analysis, and mechanism

395

Using path sampling to build better Markovian state models: Predicting the folding rate and mechanism of a tryptophan zipper beta hairpin  

E-Print Network [OSTI]

Using path sampling to build better Markovian state models: Predicting the folding rate molecular dynamics simulation data to build Markovian state models MSMs , discrete representations system, we apply these techniques to a two-dimensional model energy landscape and the folding

Snow, Christopher

396

The Great Observatories Origins Deep Survey: Constraints on the Lyman Continuum Escape Fraction Distribution of Lyman--Break Galaxies at 3.4  

E-Print Network [OSTI]

We use ultra-deep ultraviolet VLT/VIMOS intermediate-band and VLT/FORS1 narrow-band imaging in the GOODS Southern field to derive limits on the distribution of the escape fraction (f_esc) of ionizing radiation for L >~ L*(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~5.5), the highest redshift galaxy currently known with a direct detection. Its ultraviolet morphology is quite compact (R_eff=0.8, kpc physical). Three out of seven AGN are also detected in their LyC, including one at redshift z=3.951 and z850 = 26.1. From stacked data (LBGs) we set an upper limit to the average f_esc in the range 5%--20%, depending on the 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 radi...

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

2010-01-01T23:59:59.000Z

397

Hydraulic fracture mechanism in unconsolidated formations.  

E-Print Network [OSTI]

??Most models developed for hydraulic fracturing in unconsolidated sands are based on Linear Elastic Fracture Mechanics (LEFM) and tensile fracture (Mode I fracture). However, in… (more)

Hosseini, Seyed Mehran

2012-01-01T23:59:59.000Z

398

An analytical model of the swirl vane steam separator for boiling water reactors  

SciTech Connect (OSTI)

Currently, no comprehensive mechanistic model for the two-phase flow through a swirl vane steam separator is available. Therefore, an attempt has been made to develop an analytical model, using fundamental fluid mechanics, which is capable of predicting separator performance over a wide range of conditions. The developed model subdivides a typical boiling water reactor swirl vane steam separator into four distinct regions: the standpipe region, the swirl vane region, the transition region, and the free vortex region. In each region, the vapor and liquid components are treated separately and the behavior of individual droplets is determined from the drag force induced by the vapor continuum. The analytical model is used to first determine the vapor velocities throughout the separator. The drag force on the droplets is then determined, and the droplets are tracked through the separator in order to determine the exit position of each droplet. Separator performance can then be determined from this final position in terms of the fraction of droplets removed from the flow stream. In order to assess the validity of this model, the computer code SEPARATOR was developed. Among other capabilities, the code is capable of determining separator performance in terms of carryover, carryunder, and exit quality. However, due to the simplicity of the single-phase fluid treatment of the vapor continuum and the lack of data related to the average droplet diameter for flows of this nature, the results are not of significant quantitative value. The investigation performed does, however, suggest that the developed methodology, upon refinement of the single-phase fluids treatment, will yield quantitatively accurate results for nearly all separator operating conditions of interest.

Betts, C.M.; Galvin, M.R.; Green, J.R.; Guymon, V.M.; Slater, S.M.; Klein, A.C. (Oregon State Univ., Corvallis, OR (United States). Dept. of Nuclear Engineering)

1994-03-01T23:59:59.000Z

399

ETC With a GIM Mechanism  

E-Print Network [OSTI]

We construct an extended technicolor model of quarks and leptons which preserves a GIM mechanism. Furthermore, there is only a minimal technicolor sector, in accordance with recent precision measurements of electroweak parameters. We also show how to incorporate custodial SU(2) and massless neutrinos into such a model.

L. Randall

1992-10-13T23:59:59.000Z

400

Modeling and Characterization of Dynamic Failure of Soda-lime Glass Under High Speed Impact  

SciTech Connect (OSTI)

In this paper, the impact-induced dynamic failure of a soda-lime glass block is studied using an integrated experimental/analytical approach. The Split Hopkinson Pressure Bar (SHPB) technique is used to conduct dynamic failure test of soda-lime glass first. The damage growth patterns and stress histories are reported for various glass specimen designs. Making use of a continuum damage mechanics (CDM)-based constitutive model, the initial failure and subsequent stiffness reduction of glass are simulated and investigated. Explicit finite element analyses are used to simulate the glass specimen impact event. A maximum shear stress-based damage evolution law is used in describing the glass damage process under combined compression/shear loading. The impact test results are used to quantify the critical shear stress for the soda-lime glass under examination.

Liu, Wenning N.; Sun, Xin; Chen, Weinong W.; Templeton, Douglas W.

2012-05-27T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Continuum-Limit of the Upper Critical-Field H-Star-C2 for Superconducting Networks  

E-Print Network [OSTI]

H, ($"'"1 (with d the spatial dimension of the network) as the universal limiting behavior of H,*2(T) as T T,u, H 2 0. We demon- strate with several examples that this is not true for networks with low point-group symmetry. We then propose that the above... and infinite superconducting networks; in particular, for infinite periodic networks, they proposed the formula (7.) dH (bulk) (7-) (1) 2 tr&'(T) as the universal behavior of H, 2(T) in the continuum lim- it, i.e., as T T,o and H, 2 0. In the above, d...

Hu, Chia-Ren.

1987-01-01T23:59:59.000Z

402

Nonlinear elasto-plastic model for dense granular flow  

E-Print Network [OSTI]

This work proposes a model for granular deformation that predicts the stress and velocity profiles in well-developed dense granular flows. Recent models for granular elasticity (Jiang and Liu 2003) and rate-sensitive plastic flow (Jop et al. 2006) are reformulated and combined into one universal granular continuum law, capable of predicting flowing regions and stagnant zones simultaneously in any arbitrary 3D flow geometry. The unification is performed by justifying and implementing a Kroner-Lee elasto-plastic decomposition, with care taken to ensure certain continuum physical principles are necessarily upheld. The model is then numerically implemented in multiple geometries and results are compared to experiments and discrete simulations.

Ken Kamrin

2009-05-07T23:59:59.000Z

403

Modeling and Algorithmic Approaches to Constitutively-Complex, Microstructured Fluids  

SciTech Connect (OSTI)

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.

Miller, Gregory H.; Forest, Gregory

2011-12-22T23:59:59.000Z

404

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

SciTech Connect (OSTI)

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. LBNL’s 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.

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

2014-08-14T23:59:59.000Z

405

Computational Study of Copper(II) Complexation and Hydrolysis in Aqueous Solutions Using Mixed Cluster/Continuum Models  

E-Print Network [OSTI]

Computational Study of Copper(II) Complexation and Hydrolysis in Aqueous Solutions Using Mixed and thermodynamic properties of Cu(II) species in aqueous solution. 1. Introduction Copper is a key component evidence that copper may be involved in the pathogenesis of atherosclerosis, Alzheimer's diseases

Goddard III, William A.

406

Mechanical Engineering Department "The Lindbergh Lectures"  

E-Print Network [OSTI]

Mechanical Engineering Department "The Lindbergh Lectures" Thursday, January 23rd, 2014 at 12 MODELING, CONTROL, AND DESIGN Michael Zinn Assistant Professor, Mechanical Engineering Department, UW.D. in Mechanical Engineering (2005) from Stanford University. He joined the faculty at the University of Wisconsin

Wisconsin at Madison, University of

407

Models for MetaVCeramic Interface Fracture  

E-Print Network [OSTI]

ChaDter 12 Models for MetaVCeramic Interface Fracture ZHIGANG SUO C. FONG SHIH Metal shortcomingthat haslimited their wide- spread use-their tendency to fracture easily. In many systems, the low on interface fracture are reviewed in this chapter. With few exceptions, attention is limited to continuum

Suo, Zhigang

408

Current SPE Hydrodynamic Modeling and Path Forward  

SciTech Connect (OSTI)

Extensive work has been conducted on SPE analysis efforts: Fault effects Non-uniform weathered layer analysis MUNROU: material library incorporation, parallelization, and development of non-locking tets Development of a unique continuum-based-visco-plastic strain-rate-dependent material model With corrected SPE data path is now set for a multipronged approach to fully understand experimental series shot effects.

Knight, Earl E. [Los Alamos National Laboratory; Rougier, Esteban [Los Alamos National Laboratory

2012-08-14T23:59:59.000Z

409

Mechanical and Aerospace Engineering  

E-Print Network [OSTI]

Mechanical and Aerospace Engineering seminar Three Dimensional Traction Force Microscopy with Applications in Cell Mechanics abstract The interactions between biochemical and mechanical signals during-dimensional measurement techniques are needed to investigate the effect of mechanical properties of the substrate

410

Mechanical Engineer Company Description  

E-Print Network [OSTI]

Mechanical Engineer Company Description Control Solutions Inc. is a small, dynamic, and rapidly. Position Description The Mechanical Engineer is responsible for all aspects associated with the mechanical enclosures, brackets, cabling assemblies among others. Systems include mechanisms, sensors, hydraulics, among

Kostic, Milivoje M.

411

MECHANICAL ENGINEERING Ross Schlueter  

E-Print Network [OSTI]

MECHANICAL ENGINEERING Ross Schlueter Engineering Deputy For Mechanical Engineering Russ Wells Mechanical Engineering Department Deputy ELECTRONICS, SOFTWARE & INSTRUMENTATION ENGINEERING Henrik von Der Sen Mechanical Admin. Assist. Joan Wolter Electronics Admin. Assist. Marilyn Wong Division Admin

412

Defect microstructural evolution in ion irradiated metallic nanofoils: Kinetic Monte Carlo simulation versus cluster dynamics modeling and in situ transmission electron microscopy experiments  

SciTech Connect (OSTI)

Understanding materials degradation under intense irradiation is important for the development of next generation nuclear power plants. Here we demonstrate that defect microstructural evolution in molybdenum nanofoils in situ irradiated and observed on a transmission electron microscope can be reproduced with high fidelity using an object kinetic Monte Carlo (OKMC) simulation technique. Main characteristics of defect evolution predicted by OKMC, namely, defect density and size distribution as functions of foil thickness, ion fluence and flux, are in excellent agreement with those obtained from the in situ experiments and from previous continuum-based cluster dynamics modeling. The combination of advanced in situ experiments and high performance computer simulation/modeling is a unique tool to validate physical assumptions/mechanisms regarding materials response to irradiation, and to achieve the predictive power for materials stability and safety in nuclear facilities.

Xu Donghua; Wirth, Brian D. [Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Li Meimei [Division of Nuclear Engineering, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Kirk, Marquis A. [Division of Materials Science, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2012-09-03T23:59:59.000Z

413

Testing protostellar disk formation models with ALMA observations  

E-Print Network [OSTI]

Abridged: Recent simulations have explored different ways to form accretion disks around low-mass stars. We aim to present observables to differentiate a rotationally supported disk from an infalling rotating envelope toward deeply embedded young stellar objects and infer their masses and sizes. Two 3D magnetohydrodynamics (MHD) formation simulations and 2D semi-analytical model are studied. The dust temperature structure is determined through continuum radiative transfer RADMC3D modelling. A simple temperature dependent CO abundance structure is adopted and synthetic spectrally resolved submm rotational molecular lines up to $J_{\\rm u} = 10$ are simulated. All models predict similar compact components in continuum if observed at the spatial resolutions of 0.5-1$"$ (70-140 AU) typical of the observations to date. A spatial resolution of $\\sim$14 AU and high dynamic range ($> 1000$) are required to differentiate between RSD and pseudo-disk in the continuum. The peak-position velocity diagrams indicate that the...

Harsono, Daniel; Bruderer, Simon; Li, Zhi-Yun; Jorgensen, Jes

2015-01-01T23:59:59.000Z

414

A large-deformation thermo-mechanically coupled elastic-viscoplastic theory for amorphous polymers : modeling of micro-scale forming and the shape memory phenomenon  

E-Print Network [OSTI]

Amorphous polymers are important engineering materials; however, their nonlinear, strongly temperature- and rate-dependent elastic-viscoplastic behavior is still not very well understood, and is modeled by existing ...

Srivastava, Vikas

2010-01-01T23:59:59.000Z

415

Stommel’s Box Model of Thermohaline Circulation Revisited—The Role of Mechanical Energy Supporting Mixing and the Wind-Driven Gyration  

Science Journals Connector (OSTI)

The classical two-box model of Stommel is extended in two directions: replacing the buoyancy constraint with an energy constraint and including the wind-driven gyre. Stommel postulated a buoyancy constraint for the thermohaline circulation, and ...

Yu Ping Guan; Rui Xin Huang

2008-04-01T23:59:59.000Z

416

Computational Mechanistic Studies of Acid-Catalyzed Lignin Model Dimers for Lignin Depolymerization  

SciTech Connect (OSTI)

Lignin is a heterogeneous alkyl-aromatic polymer that constitutes up to 30% of plant cell walls, and is used for water transport, structure, and defense. The highly irregular and heterogeneous structure of lignin presents a major obstacle in the development of strategies for its deconstruction and upgrading. Here we present mechanistic studies of the acid-catalyzed cleavage of lignin aryl-ether linkages, combining both experimental studies and quantum chemical calculations. Quantum mechanical calculations provide a detailed interpretation of reaction mechanisms including possible intermediates and transition states. Solvent effects on the hydrolysis reactions were incorporated through the use of a conductor-like polarizable continuum model (CPCM) and with cluster models including explicit water molecules in the first solvation shell. Reaction pathways were computed for four lignin model dimers including 2-phenoxy-phenylethanol (PPE), 1-(para-hydroxyphenyl)-2-phenoxy-ethanol (HPPE), 2-phenoxy-phenyl-1,3-propanediol (PPPD), and 1-(para-hydroxyphenyl)-2-phenoxy-1,3-propanediol (HPPPD). Lignin model dimers with a para-hydroxyphenyl ether (HPPE and HPPPD) show substantial differences in reactivity relative to the phenyl ether compound (PPE and PPPD) which have been clarified theoretically and experimentally. The significance of these results for acid deconstruction of lignin in plant cell walls will be discussed.

Kim, S.; Sturgeon, M. R.; Chmely, S. C.; Paton, R. S.; Beckham, G. T.

2013-01-01T23:59:59.000Z

417

3.021J / 1.021J / 10.333J / 18.361J / 22.00J Introduction to Modeling and Simulation, Spring 2008  

E-Print Network [OSTI]

This course explores the basic concepts of computer modeling and simulation in science and engineering. We'll use techniques and software for simulation, data analysis and visualization. Continuum, mesoscale, atomistic and ...

Buehler, Markus

418

Theoretical modeling and analysis of mechanical impact driven and frequency up-converted piezoelectric energy harvester for low-frequency and wide-bandwidth operation  

Science Journals Connector (OSTI)

Abstract Vibration energy harvesters are capable of generating significant amount of power at higher frequencies rather than generating at low frequencies. Moreover, as low frequency vibrations (1–30 Hz) around the ambient environment are discursive in nature, resonance based power generators are limited to use within this low frequency range. In this paper, a mechanical impact driven and frequency up-converted wide-bandwidth piezoelectric vibration energy harvester has been proposed and demonstrated theoretically and experimentally. It converts low frequency environmental vibrations into high frequency vibration by mechanical impact. A low frequency flexible driving beam with horizontally extended tip mass, upon excitation, hits two high frequency rigid piezoelectric generating beams at the same time causing a change in the driving beam's effective stiffness that allows the device to offer approximately 180% increased ?3 dB bandwidth and more than 62% of the maximum power generation within the remaining operating frequency range as well. The overall bandwidth is 7.5 Hz within 7–14.5 Hz frequency range generating a minimum peak power of 233 ?W. A maximum of 378 ?W peak power from one generating beam is achieved under 6 ms?2 acceleration at the resonant frequency of 14.5 Hz. Output of both generating beams connected in series produces 734 ?W peak power under the same operating condition with the corresponding power density 38.8 ?W cm?3. The experimental results show some discrepancy with the theoretical results due to mechanical loss during impact and the process variations in the beam formation and assembling. The theoretical and experimental results reveal that the proposed configuration has the potential of powering small portable, handheld wireless smart devices from low frequency, specially human motion related vibrations.

Miah A. Halim; Jae Y. Park

2014-01-01T23:59:59.000Z

419

Benchmark Reaction Mechanisms and Kinetics for Lean NOx Traps...  

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

Benchmark Reaction Mechanisms and Kinetics for Lean NOx Traps Development of Chemical Kinetic Models for Lean NOx Traps Modeling the Regeneration Chemistry of Lean NOx Traps...

420

The Spitzer Infrared Spectrograph Debris Disk Catalog. I. Continuum Analysis of Unresolved Targets  

Science Journals Connector (OSTI)

During the Spitzer Space Telescope cryogenic mission, Guaranteed Time Observers, Legacy Teams, and General Observers obtained Infrared Spectrograph (IRS) observations of hundreds of debris disk candidates. We calibrated the spectra of 571 candidates, including 64 new IRAS and Multiband Imaging Photometer for Spitzer (MIPS) debris disks candidates, modeled their stellar photospheres, and produced a catalog of excess spectra for unresolved debris disks. For 499 targets with IRS excess but without strong spectral features (and a subset of 420 targets with additional MIPS 70 ?m observations), we modeled the IRS (and MIPS data) assuming that the dust thermal emission was well-described using either a one- or two-temperature blackbody model. We calculated the probability for each model and computed the average probability to select among models. We found that the spectral energy distributions for the majority of objects (~66%) were better described using a two-temperature model with warm (T gr ~ 100-500 K) and cold (T gr ~ 50-150 K) dust populations analogous to zodiacal and Kuiper Belt dust, suggesting that planetary systems are common in debris disks and zodiacal dust is common around host stars with ages up to ~1 Gyr. We found that younger stars generally have disks with larger fractional infrared luminosities and higher grain temperatures and that higher-mass stars have disks with higher grain temperatures. We show that the increasing distance of dust around debris disks is inconsistent with self-stirred disk models, expected if these systems possess planets at 30-150 AU. Finally, we illustrate how observations of debris disks may be used to constrain the radial dependence of material in the minimum mass solar nebula.

Christine H. Chen; Tushar Mittal; Marc Kuchner; William J. Forrest; Carey M. Lisse; P. Manoj; Benjamin A. Sargent; Dan M. Watson

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Modeling  

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

a single-fluid diffuse interface model in the ALE-AMR hydrodynamics code to simulate surface tension effects. We show simula- tions and compare them to other surface tension...

422

Modeling  

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

sion effects. We show the result of a test case, and compare it to the result without surface tension. The model describes droplet formation nicely. Application The ARRA-funded...

423

Using ex vivo organ culture models as surrogates to investigate morphological and functional differences of mammary glands derived from mouse strains that differ in cancer susceptibility to understand the underlying mechanisms of radiation sensitivity or resistance  

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

ex vivo organ culture models as surrogates to investigate morphological and functional ex vivo organ culture models as surrogates to investigate morphological and functional differences of mammary glands derived from mouse strains that differ in cancer susceptibility to understand the underlying mechanisms of radiation sensitivity or resistance Alvin Lo, Joni D. Mott, Jian-Hua Mao, and Mina J. Bissell Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 Goal: Within the Lawrence Berkeley National Laboratory's Low Dose SFA, as part of Project 2, we are using a systems genetics approach to determine the contribution of non-targeted and targeted radiation effects for risk of mammary carcinogenesis. The goal of this work is to characterize the mammary gland of the parental mouse strains, and the F1 and F2 generations used in these studies with respect to tissue

424

European Journal of Mechanics B/Fluids 24 (2005) 113124 Standing waves for a two-way model system for water waves  

E-Print Network [OSTI]

parameter class of model equations (which are called Boussinesq-type systems) t + ux + (u)x + auxxx - bxxt (which we refer as BBM system since it has certain common properties as the BBM equation) t + ux + (u of the advantages that (2) has over alternative Boussinesq-type systems in (1) (see Bona, Chen and Saut [1

Chen, Min

425

ENGINEERING MECHANICS SEMINARSENGINEERING MECHANICS SEMINARS THINK COMPOSITE  

E-Print Network [OSTI]

ENGINEERING MECHANICS SEMINARSENGINEERING MECHANICS SEMINARS THINK COMPOSITE "THINK outside the box" for more competitive structural COMPOSITES Dr. Melih Papila Visiting Professor, Aero/Astro Department, Stanford University. Adv. Composites and Polymer Processing Lab., Sabanci University, Istanbul. mpapila

Ponce, V. Miguel

426

In-situ Fracture Studies and Modeling of the Toughening Mechanism Present in Wrought LCAC, TZM, and ODS Molybdenum Flat Products  

SciTech Connect (OSTI)

In-situ testing, ultrasonic C-scans, and metallography were used to show that a crack-divider delamination form of thin-sheet toughening occurs in wrought Low Carbon Arc Cast (LCAC) unalloyed molybdenum, Oxide Dispersion Strengthened (ODS) molybdenum, and TZM molybdenum at temperatures {ge} the Ductile to Brittle Transition Temperature (DBTT). Cracking along boundaries relieves mechanical constraint to free ligaments that may plastically stretch to produce toughening. Anisotropy in fracture toughness with lower values in the short-transverse direction is shown to produce the crack divider delaminations at the crack tip in the LT and TL orientations. The delamination zone increases with increasing stress-intensity to sizes significantly larger than the plastic zone, which leads to large increases in fracture toughness by the thin sheet toughening mechanism. Fracture in ODS Mo-alloys proceeds mainly along grain boundaries to produce small ligaments that exhibit ductility for both LT and TL orientations resulting in a lower DBTT and higher toughness values at lower temperatures than observed in LCAC and TZM. A combination of grain boundary fracture and cleavage is prevalent in LCAC molybdenum and TZM. The predominance for microcracking along grain boundaries to leave fine, ductile ligaments in ODS molybdenum can be attributed to a fine-grained microstructure with {approx} 1-2 {micro}m thickness of sheet-like grains. The presence of mixed grain boundary fracture and cleavage in LCAC and TZM can be attributed to a microstructure with a larger thickness of sheet-like grains (4-15 {micro}m).

Cockerman, B. V. and Chan, K. S.

2007-07-01T23:59:59.000Z

427

{sup 44}Ti Nucleosynthesis Lines and Hard X-ray Continuum in Young SNRs: from INTEGRAL to Simbol-X  

SciTech Connect (OSTI)

Supemovae and their remnants are the main Galactic nucleosynthesis sites and the privileged sources of Galactic cosmic rays. The youngest of such remnants can be studied through two distinct observational features: {sup 44}Ti{gamma}-ray lines and the hard X-ray nonthermal continuum emission. The former gives unique information on the nucleosynthesis conditions occuring during the first stages of the explosion, while the latter provides clues on acceleration processes at supernova remnant shocks. In this contribution, we present new INTEGRAL results on Tycho, the remnant of a historical supernova, and on G1.9+0.3, which has been recently unveiled as the youngest Galactic supernova remnant. Expectations with Simbol-X are also addressed.

Renaud, M.; Terrier, R.; Lebrun, F. [Laboratoire APC, CNRS-UMR 7164, Universite Paris 7, 10, rue A. Domon et Leonie Duquet, 75025 Paris Cedex 13 (France); Trap, G. [CEA/DSM/IRFU/SAp, L'Orme des Merisiers, 91191 Gif-sur-Yvette (France); Laboratoire APC, CNRS-UMR 7164, Universite Paris 7, 10, rue A. Domon et Leonie Duquet, 75025 Paris Cedex 13 (France); Decourchelle, A. [CEA/DSM/IRFU/SAp, L'Orme des Merisiers, 91191 Gif-sur-Yvette (France); Vink, J. [University Utrecht, P.O. Box 80000, NL-3508 TA, Utrecht (Netherlands)

2009-05-11T23:59:59.000Z

428

QCD thermodynamics with $N_f=2+1$ near the continuum limit at realistic quark masses  

E-Print Network [OSTI]

We report on our study of QCD thermodynamics with 2+1 flavors of dynamical quarks. In this proceeding we present several thermodynamic quantities and our recent calculation of the critical temperature. In order to investigate the thermodynamic properties of QCD near the continuum limit we adopt improved staggered (p4) quarks coupled with tree-level Symanzik improved glue on $N_t=4$ and 6 lattices. The simulations are performed with a physical value of the strange quark mass and light quark masses which are in the range of $m_q/m_s=0.05-0.4$. The lightest quark mass corresponds to a pion mass of about 150 MeV.

Takashi Umeda

2006-10-03T23:59:59.000Z

429

Polycrystal model of the mechanical behavior of a Mo-TiC30vol.% metal-ceramic composite using a 3D microstructure map obtained by a dual beam FIB-SEM  

E-Print Network [OSTI]

The mechanical behavior of a Mo-TiC30 vol.% ceramic-metal composite was investigated over a large temperature range (25^{\\circ}C to 700^{\\circ}C). High-energy X-ray tomography was used to reveal the percolation of the hard titanium carbide phase through the composite. Using a polycrystal approach for a two-phase material, finite element simulations were performed on a real 3D aggregate of the material. The 3D microstructure, used as starting configuration for the predictions, was obtained by serial-sectioning in a dual beam Focused Ion Beam (FIB)-Scanning Electron Microscope (SEM) coupled to an Electron Back Scattering Diffraction system (3D EBSD, EBSD tomography). The 3D aggregate consists of a molybdenum matrix and a percolating TiC skeleton. As most BCC metals, the molybdenum matrix phase is characterized by a change in the plasticity mechanisms with temperature. We used a polycrystal model for the BCC material, which was extended to two phases (TiC and Mo). The model parameters of the matrix were determin...

Cédat, Denis; Rey, Colette; Raabe, Dierk; 10.1016/actamat.2011.11.55

2013-01-01T23:59:59.000Z

430

Mechanical & Biomedical Engineering  

E-Print Network [OSTI]

Mechanical & Biomedical Engineering Department BACHELOR OF SCIENCE IN MECHANICAL ENGINEERING COURSE 105 Mechanical Engineering Graphics 3 CHEM 111L College Chemistry Lab (DLN) 1 ENGL 102 English PHYS 211 Mechanics, Waves & Heat (DLN) 4 UF 100 Intellectual Foundations 3 PHYS 211L Mechanics, Waves

Barrash, Warren

431

Modeling  

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

ALE-AMR ALE-AMR code Wangyi Liu, John Bernard, Alex Friedman, Nathan Masters, Aaron Fisher, Velemir Mlaker, Alice Koniges, David Eder June 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 equations is an additional term in the stress tensor. We show results of applying the model to an expanding Al droplet surrounded by an Al vapor, where additional droplets are created. 1 Introduction The Neutralized Drift Compression Experiment II (NDCX II) is an induction accelerator planned for initial commissioning in 2012. The final design calls for a 3 MeV, Li+ ion beam, delivered in a bunch with characteristic pulse duration of 1 ns, and transverse dimension of order 1 mm. The

432

On the Role of Continuum-driven Eruptions in the Evolution of Very Massive Stars and Population III Stars  

Science Journals Connector (OSTI)

We suggest that the mass lost during the evolution of very massive stars may be dominated by optically thick, continuum-driven outbursts or explosions, instead of by steady line-driven winds. In order for a massive star to become a Wolf-Rayet star, it must shed its hydrogen envelope, but new estimates of the effects of clumping in winds from O-type stars indicate that line driving is vastly insufficient. We discuss massive stars above roughly 40-50 M?, which do not become red supergiants and for which the best alternative is mass loss during brief eruptions of luminous blue variables (LBVs). Our clearest example of this phenomenon is the 19th century outburst of ? Carinae, when the star shed 12-20 M? or more in less than a decade. Other examples are circumstellar nebulae of LBVs and LBV candidates, extragalactic ? Car analogs (the so-called supernova impostors), and massive shells around supernovae and gamma-ray bursters. We do not yet fully understand what triggers LBV outbursts or what supplies their energy, but they occur nonetheless, and they present a fundamental mystery in stellar astrophysics. Since line opacity from metals becomes too saturated, the extreme mass loss probably arises from a continuum-driven wind or a hydrodynamic explosion, both of which are insensitive to metallicity. As such, eruptive mass loss could have played a pivotal role in the evolution and ultimate fate of massive metal-poor stars in the early universe. If they occur in these Population III stars, such eruptions would also profoundly affect the chemical yield and types of remnants from early supernovae and hypernovae thought to be the origin of long gamma-ray bursts.

Nathan Smith; Stanley P. Owocki

2006-01-01T23:59:59.000Z

433

Constitutive Model for the Time-Dependent Mechanical Behavior of 430 Stainless Steel and FeCrAlY Foams in Sulfur-Bearing Environments  

SciTech Connect (OSTI)

The mechanical behavior of 430 stainless steel and pre-oxidized FeCrAlY open-cell foam materials of various densities was evaluated in compression at temperatures between 450 C and 600 C in an environment containing hydrogen sulfide and water vapor. Both materials showed negligible corrosion due to the gaseous atmosphere for up to 168 hours. The monotonic stress-strain response of these materials was found to be dependent on both the strain rate and their density, and the 430 stainless steel foam materials exhibited less stress relaxation than FeCrAlY for similar experimental conditions. Using the results from multiple hardening-relaxation and monotonic tests, an empirical constitutive equation was derived to predict the stress-strain behavior of FeCrAlY foams as a function of temperature and strain rate. These results are discussed in the context of using these materials in a black liquor gasifier to accommodate the chemical expansion of the refractory liner resulting from its reaction with the soda in the black liquor.

Hemrick, James Gordon [ORNL; Lara-Curzio, Edgar [ORNL

2013-01-01T23:59:59.000Z

434

Mechanical Engineering Graduate Student  

E-Print Network [OSTI]

......................................................................................9 Engineering Career Services ................................................................9 McMechanical Engineering Graduate Student Handbook January 2014 Department of Mechanical Engineering University of Wisconsin-Madison #12;Mechanical Engineering Web Page: http://www.engr.wisc.edu/me Graduate

Wisconsin at Madison, University of

435

Mechanical & Industrial Engineering  

E-Print Network [OSTI]

Mechanical & Industrial Engineering 1 Welcome MIE Industrial Advisory Board October 15, 2010 #12;Mechanical & Industrial Engineering 2 MIE Dorothy Adams Undergraduate/Graduate Secretary David Schmidt Associate Professor & Graduate Program Director #12;Mechanical & Industrial Engineering 3 MIE James Rinderle

Mountziaris, T. J.

436

MECHANICAL ENGINEERING UNDERGRADUATE MAJOR  

E-Print Network [OSTI]

HANDBOOK FOR MECHANICAL ENGINEERING UNDERGRADUATE MAJOR Old Dominion University Department of Mechanical Engineering Batten College of Engineering and Technology Norfolk, Virginia 23529-0247 #12;TABLE OF CONTENTS MECHANICAL ENGINEERING HANDBOOK

437

Mechanical engineering Department Seminar  

E-Print Network [OSTI]

Mechanical engineering Department Seminar Katia Bertoldi Harvard University Soft materials in response to diverse stimuli. While the mechanical attributes - such as energy absorption, stiffness and switchable functionalities. Katia Bertoldi is an Assistant Professor of Applied Mechanics at Harvard

438

Monroe Thomas, Mechanical Technician  

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

Monroe Thomas, Mechanical Technician Print The weekend before the ALS was scheduled to start up again after the most recent shutdown, mechanical technician Monroe Thomas kept...

439

Sandia National Laboratories: Careers: Mechanical Engineering  

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

Mechanical Engineering Mechanical Engineering Engineering photo Sandia mechanical engineers design and develop advanced components and systems for national-defense programs, homeland security, and other applications. Mechanical engineers at Sandia work on design, analysis, manufacturing, and test activities in many areas, including nuclear weapons and power, renewable energy, intelligent machines, robotics, pulsed power, missile defense, remote sensing, advanced manufacturing, and micro- and nanosystems. Sandia mechanical engineers are an integral part of multidisciplinary teams that employ state-of-the-art technologies, such as sophisticated software tools for design, analysis, modeling, and simulation; micro- and nanotechnologies; and advanced materials, materials processing, and fabrication.

440

Abstract PD08-05: Spanning the Continuum to assess, serve and navigate Latinas with breast cancer: A Tale of Six Projects  

Science Journals Connector (OSTI)

...Health Science Center at San Antonio, TX; Redes en Accion: The National Latino Cancer...Continuum. Here we report the efforts of Redes En Accion: The National Latino Cancer...and the National Cancer Institute via Redes En Accion (U01-CA86117 and U54 CA153511-01...

AG Ramirez; AE Holden; K Gallion; SA SanMiguel; E Munoz; FJ Penedo; EJ Perez-Stable; GG Talavera; JE Carrillo; ME Fernandez

2012-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 93, NO. All, PAGES 12,817-12,825, NOVEMBER 1, 1988 The Polarization of EscapingTerrestrial Continuum Radiation  

E-Print Network [OSTI]

The Polarization of EscapingTerrestrial Continuum Radiation D. A. GURNETT, W. CALVERT,AND R. L. HUFF Departmentof, Japan PlasmawavemeasurementsfromtheDE 1(DynamicsExplorer1)spacecraftareusedto determinethe polarization of an escapingterrestrialcontinuum radiation event that occurredon March 2, 1982.The sourceof the radiationwasdeterminedby

Gurnett, Donald A.

442

Numerical analysis of hypersonic continuum and rarefied gas flows near blunt probes is presented under conditions of intensive gas blowing from the surface.  

E-Print Network [OSTI]

1 Abstract Numerical analysis of hypersonic continuum and rarefied gas flows near blunt probes injection, hydrogen combustion, hypersonic flow, exponential box-scheme, direct-simulation Monte-Carlo method. 1 Introduction Numerical and experimental studies [1, 2] of aerothermodynamics of hypersonic

Riabov, Vladimir V.

443

Continuous Shape Estimation of Continuum Robots Using X-ray Images Edgar J. Lobaton1, Jinghua Fu2, Luis G. Torres2, and Ron Alterovitz2  

E-Print Network [OSTI]

], and highly articulated robotic manipulators [5]. To fully harness the potential of these devices, physicians. INTRODUCTION Continuum robots have a continuously bending, curvilin- ear structure and have the potential) under award #R21EB011628. 1E. J. Lobaton is with the Department of Electrical and Computer Engineering

Alterovitz, Ron

444

A 3D radiative transfer framework: I. non-local operator splitting and continuum scattering problems  

E-Print Network [OSTI]

We describe a highly flexible framework to solve 3D radiation transfer problems in scattering dominated environments based on a long characteristics piece-wise parabolic formal solution and an operator splitting method. We find that the linear systems are efficiently solved with iterative solvers such as Gauss-Seidel and Jordan techniques. We use a sphere-in-a-box test model to compare the 3D results to 1D solutions in order to assess the accuracy of the method. We have implemented the method for static media, however, it can be used to solve problems in the Eulerian-frame for media with low velocity fields.

Peter H. Hauschildt; E. Baron

2006-01-09T23:59:59.000Z

445

Mechanics of Peridynamic Membranes  

National Nuclear Security Administration (NNSA)

JBAidun AdvMatSci090831 JBAidun AdvMatSci090831 1 Accurate Prediction of Dynamic Fracture with Peridynamics John B. Aidun & Stewart A. Silling Multiscale Dynamic Material Modeling Sandia National Laboratories Prague, Czech Republic August 30 - September 3, 2009 Joint U.S.-Russian Conference on Advances in Materials Science SAND2009-5095C Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. JBAidun AdvMatSci090831 2 Fracture Mechanics Theory and Dynamic Fracture * Onset of crack growth can be accurately predicted * Crack growth speed and direction cannot! Wanted: A successful method for simulating Dynamic Fracture * Such a method must be able to reproduce the

446

NREL: Continuum Magazine - New Facility to Transform U.S. Energy  

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

Energy Systems Integration Facility to Transform U.S. Energy Infrastructure Energy Systems Integration Facility to Transform U.S. Energy Infrastructure Issue 1 Print Version Share this resource Energy Systems Integration Facility to Transform U.S. Energy Infrastructure The nation's electricity infrastructure needs a 21st century overhaul. NREL's newest research facility will lead the way. Everyone knows that Thomas Edison invented the light bulb. But not many know that one of his greatest inventions was not the invention itself, but the research laboratory from whence it came. Edison's original research and development laboratory in Menlo Park, N.J., was the first of its kind and revolutionized the process of technological research. Later, the fusion of business and technology achieved at his West Orange, N.J. facility provided a model for modern corporate and governmental

447

NREL: Continuum Magazine - At $2.15 a Gallon, Cellulosic Ethanol Could Be  

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

At $2.15 a Gallon, Cellulosic Ethanol Could Be Cost Competitive At $2.15 a Gallon, Cellulosic Ethanol Could Be Cost Competitive Issue 5 Print Version Share this resource At $2.15 a Gallon, Cellulosic Ethanol Could Be Cost Competitive DOE challenge met-research advances cut costs to produce fuel from non-food plant sources. A photo showing a silhouette of a man wearing glass in a dark room lit only by a band of light consisting or red, blue, and white dots (26186). Enlarge image In NREL's new Energy Systems Integration Facility, the Insight Collaboration Laboratory shows a 3D model of cellulose microfibrils. Photo by Dennis Schroeder, NREL Imagine a near perfect transportation fuel-it's clean, domestic, abundant, and renewable. Now imagine that it's also affordable. Bringing this vision closer to reality was the challenge the U.S.

448

Mechanical & Industrial Engineering  

E-Print Network [OSTI]

Mechanical & Industrial Engineering 1 Welcome MIE Industrial Advisory Board May 5th, 2011 #12;Mechanical & Industrial Engineering 2 IAB 2010-2011 · David K. Anderson ­ Alden Research Laboratory, Inc went on for three weeks Mechanical & Industrial Engineering 6 #12;Reza Shahbazian Yassar Mechanical

Mountziaris, T. J.

449

Career Map: Mechanical Engineer  

Broader source: Energy.gov [DOE]

The Wind Program's Career Map provides job description information for Mechanical Engineer positions.

450

Mechanical Engineering Undergraduate  

E-Print Network [OSTI]

Mechanical Engineering Department Undergraduate Advising Manual for Bachelor of Science Degrees in Mechanical Engineering and Engineering Mechanics 2011-2012 - Updated April 15, 2012 #12;Johns Hopkins University ­ Department of Mechanical Engineering 2011-2012 Undergraduate Student Advising Manual Page 2

Ghosh, Somnath

451

Mechanical engineering Department Seminar  

E-Print Network [OSTI]

Mechanical engineering Department Seminar James Bird Department of Mechanical Engineering Boston ­ are discussed. James Bird is an Assistant Professor in the Mechanical Engineering Department at Boston completed post-doctoral research at MIT. His research interests include experimental fluid mechanics

452

Mechanical Engineering Undergraduate  

E-Print Network [OSTI]

Mechanical Engineering Department Undergraduate Advising Manual for Bachelor of Science Degrees in Mechanical Engineering and Engineering Mechanics 2012-2013 - Updated July 14, 2013 #12;Johns Hopkins University ­ Department of Mechanical Engineering 2012-2013 Undergraduate Student Advising Manual Page 2

Ghosh, Somnath

453

Mechanical Engineering & Thermal Group  

E-Print Network [OSTI]

Mechanical Engineering & Thermal Group The Mechanical Engineering (ME) & Thermal Group at LASP has, and ground- based mechanical systems. Instrument Design Building on decades of design experience that has evolved with the complexity of instrument design demands, LASP mechanical engineers develop advanced

Mojzsis, Stephen J.

454

Combined Quantum Mechanical and Molecular Mechanics Studies of...  

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

Mechanical and Molecular Mechanics Studies of the Electron-Transfer Reactions Involving Carbon Tetrachloride in Combined Quantum Mechanical and Molecular Mechanics Studies of the...

455

Int. J. Modelling, Identification and Control, Vol. 2, No. 4, 2007 Copyright 2007 Inderscience Enterprises Ltd.  

E-Print Network [OSTI]

lead to process optimisation. Recently, a continuum mechanics framework was presented for granular material handling processes in industrial production lines (Chapelle et al., 2004; Christakis et al., 2002 for the equations of mass, momentum and energy for the description of material flow under various scenarios (filling

Christakis, Nikolaos

456

Dust continuum emission as a tracer of gas mass in galaxies  

E-Print Network [OSTI]

We use a sample of 36 galaxies from the KINGFISH (Herschel IR), HERACLES (IRAM CO), and THINGS (VLA HI) surveys to study empirical relations between Herschel infrared (IR) luminosities and the total mass of the interstellar gas (H2+HI). 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 (SPIRE500). 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 (H2) 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 ...

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

2014-01-01T23:59:59.000Z

457

Sandia National Laboratories: Mechanical Testing  

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

EnergyNuclear Energy Systems Laboratory (NESL) Brayton LabMechanical Testing Mechanical Testing Mechanical Testing Overview Mechanical 1-2 (2008). Standard Test Methods for...

458

Kinematic calibration of the parallel Argos mechanism  

Science Journals Connector (OSTI)

This paper deals with the kinematic calibration of the Argos mechanism which is a novel, spherical parallel structure having 3 rotational degrees of freedom. Its design is based on 3 actuators carrying a pantograph each which are connected to the end-effector ... Keywords: Argos mechanism, Implicit calibration, Kinematic calibration, Parametric calibration models

Peter Vischer; Reymond Clavel

2000-11-01T23:59:59.000Z

459

NSLS Mechanical Tech  

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

Mechanical Tech Mechanical Tech The Mechanical Technician group is supervised by Robert Scheuerer and consists of Mechanical Technicians with fabrication/machining, assembly, installation, and alignment/surveying skills. This group also serves as an interface to Central Fabrication Services when more complex or larger fabrication efforts are needed. The Mechanical Tech group is responsible for fabricating, installing, aligning, and troubleshooting the mechanical hardware used on NSLS and SDL accelerators, front ends, and User beamlines, often starting solely from Mechanical Design group drawings or CAD files. The Mechanical Tech Group is responsible for the fabrication, assembly and installation of components at the NSLS. These components include all mechanical assemblies and RF cavities. Another part of their job is to

460

Quasi-continuum photoluminescence: Unusual broad spectral and temporal characteristics found in defective surfaces of silica and other materials  

SciTech Connect (OSTI)

We previously reported a novel photoluminescence (PL) with a distribution of fast decay times in fused silica surface flaws that is correlated with damage propensity by high fluence lasers. The source of the PL was not attributable to any known silica point defect. Due to its broad spectral and temporal features, we here give this PL the name quasi-continuum PL (QC-PL) and describe the features of QC-PL in more detail. The primary features of QC-PL include broad excitation and emission spectra, a broad distribution of PL lifetimes from 20 ps to 5?ns, continuous shifts in PL lifetime distributions with respect to emission wavelength, and a propensity to photo-bleach and photo-brighten. We found similar PL characteristics in surface flaws of other optical materials, including CaF{sub 2}, DKDP, and quartz. Based on the commonality of the features in different optical materials and the proximity of QC-PL to surfaces, we suggest that these properties arise from interactions associated with high densities of defects, rather than a distribution over a large number of types of defects and is likely found in a wide variety of structures from nano-scale composites to bulk structures as well as in both broad and narrow band materials from dielectrics to semiconductors.

Laurence, Ted A., E-mail: laurence2@llnl.gov; Bude, Jeff D.; Shen, Nan; Steele, William A.; Ly, Sonny [Physical and Life Sciences and National Ignition Facility, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States)

2014-02-28T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Gas Bubbles and Gas Pancakes at Liquid/Solid Interface: A Continuum Theory Incorporated with Molecular Interactions  

E-Print Network [OSTI]

The states of gas accumulated at the liquid-solid interface are analyzed based on the continuum theory where the Hamaker constant is used to describe the long-range interaction at the microscopic scale. The Hamaker constant is always negative, whereas the gas spreading coefficient can be either sign. Despite the complexity of gas, including that the density profile may not be uniform due to absorption on both solid and liquid surfaces, we predict three possible gas states at the liquid-solid interface, i.e. complete wetting, partial wetting and pseudopartial wetting. These possible gas states correspond respectively to a gas pancake (or film) surrounded by a wet solid, a gas bubble with a finite contact angle, and a gas bubble(s) coexisting with a gas pancake. Typical thickness of the gas pancakes is at the nanoscale within the force range of the long-range interaction, whereas the radius of the gas bubbles can be large. The state of gas bubble(s) coexisting with a gas film is predicted theoretically for the first time. Our theoretical results can contribute to the development of a unified picture of gas nucleation at the liquid-solid interface.

Zhaoxia Li; Xuehua Zhang; Lijuan Zhang; Xiaocheng Zeng; Jun Hu; Haiping Fang

2007-10-27T23:59:59.000Z

462

Two-phase modeling of deflagration-to-detonation transition in granular materials: A critical examination of modeling issues  

E-Print Network [OSTI]

Two-phase modeling of deflagration-to-detonation transition in granular materials: A critical the deflagration-to-detonation transition DDT in granular explosives is critically reviewed. The continuum, analysis and numerical simulation of deflagration- to-detonation transition DDT in porous energetic

Kapila, Ashwani K.

463

A Computational Study of the Deacylation Mechanism of Human Butyrylcholinesterase  

Science Journals Connector (OSTI)

To investigate the mechanism of the deacylation reaction in the active site of human butyrylcholinesterase (BuChE), we carried out quantum mechanical (QM) calculations on cluster models of the active site built from a crystallographic structure. The ...

Dimas Suárez; Natalia Díaz; Juan Fontecilla-Camps; Martin J. Field

2006-05-19T23:59:59.000Z

464

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

SciTech Connect (OSTI)

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.

Liu, H.H.; Rutqvist, J.

2009-10-01T23:59:59.000Z

465

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

SciTech Connect (OSTI)

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.

Vogler, Tracy; Lammi, Christopher James

2014-10-01T23:59:59.000Z

466

E-Print Network 3.0 - adhesion mechanism implications Sample...  

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

law of the adhesive in question can be obtained. Polymer joints with different mechanical... methods for modelling the mechanical behaviour of adhesively bonded joints in...

467

Compliant mechanism learning toolkit  

E-Print Network [OSTI]

This thesis concerns a toolkit designed to assist in learning the behavior of complaint mechanisms. In the design of complaint mechanisms, increasingly complicated designs behave in ways that are harder to intuitively ...

Allard, Nicholas (Nicholas A.)

2006-01-01T23:59:59.000Z

468

Mechanical & Industrial Engineering  

E-Print Network [OSTI]

Mechanical & Industrial Engineering Mario A. Rotea Professor and Department Head #12;2Mechanical & Industrial Engineering Outline · Undergraduate Degree Programs · Graduate Degree Programs · The Faculty · The Research · Summary #12;3Mechanical & Industrial Engineering Undergraduate Programs ­ BSME & BSIE 0 20 40 60

Mountziaris, T. J.

469

Mechanical engineering Department Seminar  

E-Print Network [OSTI]

Mechanical engineering Department Seminar Shuodao Wang Postdoctoral Fellow University of Illinois, Urbana-Champaign Mechanical Design and Fabrication Techniques for Bio-Electronic Systems 11:00 AM Friday that bridge this gap in mechanics and form will create new opportunities in bio-inspired and bio

Lin, Xi

470

Mechanical and Aerospace Engineering  

E-Print Network [OSTI]

Mechanical and Aerospace Engineering Abstract Solid materials used in energy conversion and storage that couples the mechanical and chemical (or electrochemical) fields in solids via the use of stress-chemo- mechanical theory, two examples of practical interest will be discussed, namely, solid oxide fuel cells

471

Mechanical engineering Department Seminar  

E-Print Network [OSTI]

Mechanical engineering Department Seminar Maureen Lynch Postdoctoral Fellow Cornell University Mechanical Loading Decreases Osteolysis and Tumor Formation via Effects on Bone Remodeling 11:00 AM Friday to mechanical stimuli in the skeleton, yet the role of biomechanical loading remains poorly characterized

Lin, Xi

472

Victor Yakhot Mechanical Engineering  

E-Print Network [OSTI]

to flows of strongly non-linear fluids relevant for mechanical engineering, polymers and bio-fluid dynamicsVictor Yakhot Mechanical Engineering UniversalReynoldsNumberofTransition,Renormalizationand Mechanical Engineering 11 AM Friday, October 31st Room 245, 110 Cummington Mall Refreshments served at 10

Lin, Xi

473

AFirst steps in VLA continuum data reduction with The NRAO Astronomical Image Processing System (AIPS) is a software package for interac-  

E-Print Network [OSTI]

://archive.nrao.edu/archive/advquery.jsp. Once we have the uv­data file, the next step is to load it in AIPS. To do this, it is necessary continuum data reduction with AIPS A.1 Loading and inspecting the data To load typical uv­data files from and calibrating the data. FILLM Using the FILLM task we load a uv­data file into AIPS. Multiple VLA archive files

Estalella, Robert

474

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

SciTech Connect (OSTI)

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.

Lee, Hsu-Tai; Karr, Jennifer; Su, Yu-Nung; Liu, Sheng-Yuan; Takami, Michihiro [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Liao, Wei-Ting [Department of Mechanical Engineering, National Taiwan University, 1 Roosevelt Rd., Section 4, Taipei 10617, Taiwan (China); Froebrich, Dirk; Ioannidis, Georgios [Centre for Astrophysics and Planetary Science, University of Kent, Canterbury CT2 7NH (United Kingdom); Lee, Yong-Hyun [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Duan, Hao-Yuan, E-mail: htlee@illinois.edu [Institute of Astronomy and Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan (China)

2013-10-01T23:59:59.000Z

475

Microstructural coarsening effects on redox instability and mechanical damage in solid oxide fuel cell anodes  

Science Journals Connector (OSTI)

In state-of-the-art high temperature solid oxide fuel cells (SOFCs) a porous composite of nickel and yttria stabilized zirconia (Ni/YSZ) is employed as the anode. The rapid oxidation of Ni into NiO is regarded as the main cause of the so-called reduction-oxidation (redox) instability in Ni/YSZ anodes due to the presence of extensive bulk volume changes associated with this reaction. As a consequence the development of internal stresses can lead to performance degradation and/or structural failure. In this study we employ a recently developed continuum formalism to quantify the mechanical deformation behavior and evolution of internal stresses in Ni/YSZ porous anodes due to re-oxidation. In our approach a local failure criterion is coupled to the continuum framework in order to account for the heterogeneous damage accumulation in the YSZ phase. The hallmark of our approach is the ability to track the spatial evolution of mechanical damage and capture the interaction of YSZ damaged regions with the local microstructure. Simulation results highlight the importance of the microstructure characterized by Ni to YSZ particle size ratio on the redox behavior and damage accumulation in as-synthesized SOFC anode systems. Moreover a redox-strain-to-failure criterion is developed to quantify the degree by which coarsened anode microstructures become more susceptible to mechanical damage during re-oxidation.

F. Abdeljawad; M. Haataja

2013-01-01T23:59:59.000Z

477

Modeling Different Failure Mechanisms in Metals  

E-Print Network [OSTI]

be expressed in the Voigt notation as (2.4) The effective plastic strain increment, , can be expressed as [86] (2.5) 16 where denotes the formal inverse of . is related to by [86] (2.6) Eqs. (2.3) and (2.5) provide an appropriate measure....10) Eq. (2.10) can be formally inverted to (2.11) Eq. (2.11) can be rewritten in terms of the principal components as (2.12) Assume the out-of-plane stresses to vanish. This implies that and , where denotes the mean stress. Eq. (2.12) can...

Zhang, Liang

2012-02-14T23:59:59.000Z

478

Comparing fluid mechanics models with experimental data  

Science Journals Connector (OSTI)

...As shown in figure 4, the flying ani- mal is simply replaced...8) is now seen to be the disk loading, Qd = W Sd , (4...flapping bird. (b) The wake of a flying bird Figure 8 shows a combined...studies of the wakes of freely-flying birds in a low- turbulence...

2003-01-01T23:59:59.000Z

479

A mechanical model of tunnelling Amaury Mouchet  

E-Print Network [OSTI]

to the Klein-Gordon string (as described in [1]) and located at x = ±a/2 (a > 0). When the oscillation frequency of the free oscillators 0 is below the "infra-red" cut-off on the Klein-Gordon string 0] but at finite distance the string connecting the two oscillators lifts the degeneracies between the two

Paris-Sud XI, Université de

480

Mechanical seal assembly  

DOE Patents [OSTI]

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.

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

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mechanics continuum modeling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Mechanical seal assembly  

DOE Patents [OSTI]

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.

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

2002-01-01T23:59:59.000Z

482

Heterogeneous actor modeling  

Science Journals Connector (OSTI)

Complex systems demand diversity in the modeling mechanisms. This "roadmap" paper prescribes an approach to modeling based on concurrent communicating components actors), where a diversity of orchestration strategies govern the execution and interaction ... Keywords: heterogeneity, models of computation, ptolemy

Edward A. Lee

2011-10-01T23:59:59.000Z

483

Development of Advanced Thermal-Hydrological-Mechanical-Chemical...  

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

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

484

Associative algebraic approach to logarithmic CFT in the bulk: the continuum limit of the gl(1|1) periodic spin chain, Howe duality and the interchiral algebra  

E-Print Network [OSTI]

We develop in this paper the principles of an associative algebraic approach to bulk logarithmic conformal field theories (LCFTs). We concentrate on the closed $gl(1|1)$ spin-chain and its continuum limit - the $c=-2$ symplectic fermions theory - and rely on two technical companion papers, "Continuum limit and symmetries of the periodic gl(1|1) spin chain" [Nucl. Phys. B 871 (2013) 245-288] and "Bimodule structure in the periodic gl(1|1) spin chain" [Nucl. Phys. B 871 (2013) 289-329]. Our main result is that the algebra of local Hamiltonians, the Jones-Temperley-Lieb algebra JTL_N, goes over in the continuum limit to a bigger algebra than the product of the left and right Virasoro algebras. This algebra, S - which we call interchiral, mixes the left and right moving sectors, and is generated, in the symplectic fermions case, by the additional field $S(z,\\bar{z})=S_{ab}\\psi^a(z)\\bar{\\psi}^b(\\bar{z})$, with a symmetric form $S_{ab}$ and conformal weights (1,1). We discuss in details how the Hilbert space of the LCFT decomposes onto representations of this algebra, and how this decomposition is related with properties of the finite spin-chain. We show that there is a complete correspondence between algebraic properties of finite periodic spin chains and the continuum limit. An important technical aspect of our analysis involves the fundamental new observation that the action of JTL_N in the $gl(1|1)$ spin chain is in fact isomorphic to an enveloping algebra of a certain Lie algebra, itself a non semi-simple version of $sp(N-2)$. The semi-simple part of JTL_N is represented by $Usp(N-2)$, providing a beautiful example of a classical Howe duality, for which we have a non semi-simple version in the full JTL image represented in the spin-chain. On the continuum side, simple modules over the interchiral algebra S are identified with "fundamental" representations of $sp(\\infty)$.

A. M. Gainutdinov; N. Read; H. Saleur

2014-09-30T23:59:59.000Z

485

Nuclear response beyond the Fermi gas model  

E-Print Network [OSTI]

The Fermi gas model, while providing a reasonable qualitative description of the continuum nuclear response, does not include the effects of dynamical nucleon-nucleon correlations in the initial and final states, that have long been recognized to play a critical role in specific kinematical regions. We review a many-body approach in which these effects are consistently taken into account and discuss the results of a calculation of the quasielastic neutrino-oxygen cross section as an illustrative example.

Omar Benhar

2003-07-14T23:59:59.000Z

486

Fracture mechanics of cellular glass  

SciTech Connect (OSTI)

Cellular glasses are prime candidate materials for the structural substrate of mirrored glass for solar concentrator reflecting panels. These materials are brittle, however, and susceptible to mechanical failure from slow crack growth caused by a stress corrosion mechanism. The results are detailed of one part of a program established to develop improved cellular glasses and to characterize the behavior of these and commercially available materials. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials are developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region I may be slower, by orders of magnitude, than that found in dense glasses.

Zwissler, J.G.; Adams, M.A.

1981-02-01T23:59:59.000Z

487

Mechanical Properties of Nanocrystal Supercrystals  

E-Print Network [OSTI]

and Its Impact on Mechanical Properties. MacromoleculesO. L. ; Minor, A. M. , Mechanical annealing and source-Mechanical Properties of Nanocrystal Supercrystals Enrico

Tam, Enrico

2010-01-01T23:59:59.000Z

488

Mechanics of Funding matrix  

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

FUNDING MECHANISMS FUNDING MECHANISMS Funding Mechanism Advantages Disadvantages Comments 1. From Doe to regional organizations * * Facilitates a broad, regional approach to planning and implementation that enhances consistency and uniformity * * Especially beneficial for new programs where early planning is needed * * Simplifies communication for DOE to have only one point of contact for information and discussion * * Cooperative agreement mechanism has proven relatively simple to administer * * Approach would require modification for Tribes * * Would also require that funding be provided to individual States to enable them to participate in the process, since planning authority and responsibility rests with the individual State * * Differs from OCRWM approach to 180(c) funding * * Introduces another layer of

489

Technology Partnering Mechanisms  

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

expand a business with INL technologies, or require business support our Technology Transfer team is available to discuss the following contractual mechanisms: Cooperative...

490

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

SciTech Connect (OSTI)

This report documents the development, demonstration and validation of a mesoscale, microstructural evolution model for simulation of zirconium hydride ?-ZrH1.5 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 UFD’s 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.

Veena Tikare; Philippe Weck; Peter Schultz; Blythe Clark; John Mitchell; Michael Glazoff; Eric Homer

2014-10-01T23:59:59.000Z

491

Rock mechanics activities at the Waste Isolation Pilot Plant  

SciTech Connect (OSTI)

The application of rock mechanics at nuclear waste repositories is a true multidisciplinary effort. A descrip