Sample records for viscoelastic deformation model

  1. A Four-Dimensional Viscoelastic Deformation Model For Long Valley...

    Open Energy Info (EERE)

    and slip across the South Moat fault (SMF) in late 1997. We extend the spherical VE shell model of Newman et al. (Newman, A.V., Dixon, T.H., Ofoegbu, G., Dixon, J.E., 2001....

  2. A Multiscale Model for Coupled Heat Conduction and Deformations of Viscoelastic Composites

    E-Print Network [OSTI]

    Khan, Kamran Ahmed

    2012-07-16T23:59:59.000Z

    This study introduces a multiscale model for analyzing nonlinear thermo-viscoelastic responses of particulate composites. A simplified micromechanical model consisting of four sub-cells, i.e., one particle and three matrix sub-cells is formulated...

  3. A theory of finite deformation magneto-viscoelasticity

    E-Print Network [OSTI]

    Saxena, Prashant; Steinmann, Paul

    2015-01-01T23:59:59.000Z

    This paper deals with the mathematical modelling of large strain magneto-viscoelastic deformations. Energy dissipation is assumed to occur both due to the mechanical viscoelastic effects as well as the resistance offered by the material to magnetisation. Existence of internal damping mechanisms in the body is considered by decomposing the deformation gradient and the magnetic induction into `elastic' and `viscous' parts. Constitutive laws for material behaviour and evolution equations for the non-equilibrium fields are derived that agree with the laws of thermodynamics. To illustrate the theory the problems of stress relaxation, magnetic field relaxation, time dependent magnetic induction and strain are formulated and solved for a specific form of the constitutive law. The results, that show the effect of several modelling parameters on the deformation and magnetisation process, are illustrated graphically.

  4. Non-linear viscoelastic deformation of polymeric solutions

    E-Print Network [OSTI]

    Sanchez Reyes, Javier

    2000-01-01T23:59:59.000Z

    NON-LINEAR VISCOELASTIC DEFORMATION OF POLYMERIC SOLUTIONS A Thesis by JAVIER SANCHEZ REYES 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 2000 Major Subject: Chemical Engineering NON-LINEAR VISCOELASTIC DEFORMATION OF POLYMERIC SOLUTIONS A Thesis by JAVIER SANCHEZ REYES Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of MASTER...

  5. Viscoelastic{Viscoplastic Damage Model for Asphalt Concrete

    E-Print Network [OSTI]

    Graham, Michael A.

    2010-10-12T23:59:59.000Z

    This thesis presents a continuum model for asphalt concrete incorporating non- linear viscoelasticity, viscoplasticity, mechanically-induced damage and moisture- induced damage. The Schapery single-integral viscoelastic model describes the nonlinear...

  6. Coupled heat conduction and deformation in a viscoelastic composite cylinder 

    E-Print Network [OSTI]

    Shah, Sneha

    2010-01-16T23:59:59.000Z

    This study analyzes the thermo-mechanical response of a composite cylinder made up of two layers of linear isotropic viscoelastic materials that belong to the class of non-Thermorheologically Simple Material. The effect of time-varying temperature...

  7. Coupled heat conduction and deformation in a viscoelastic composite cylinder

    E-Print Network [OSTI]

    Shah, Sneha

    2010-01-16T23:59:59.000Z

    This study analyzes the thermo-mechanical response of a composite cylinder made up of two layers of linear isotropic viscoelastic materials that belong to the class of non-Thermorheologically Simple Material. The effect of time-varying temperature...

  8. A micromechanical model for a viscoelastic cohesive zone

    E-Print Network [OSTI]

    Searcy, Chad Randall, 1972-

    1998-01-01T23:59:59.000Z

    A micromechanical model for a viscoelastic cohesive aphics. zone is formulated herein. Care has been taken in the construction of a physically-based continuum mechanics model of the damaged region ahead of the crack tip. The homogenization...

  9. Viscoelastic Models of Tidally Heated Exomoons

    E-Print Network [OSTI]

    Dobos, Vera

    2015-01-01T23:59:59.000Z

    Tidal heating of exomoons may play a key role in their habitability, since the elevated temperature can melt the ice on the body even without significant solar radiation. The possibility of life is intensely studied on Solar System moons such as Europa or Enceladus, where the surface ice layer covers tidally heated water ocean. Tidal forces may be even stronger in extrasolar systems, depending on the properties of the moon and its orbit. For studying the tidally heated surface temperature of exomoons, we used a viscoelastic model for the first time. This model is more realistic than the widely used, so-called fixed Q models, because it takes into account the temperature dependency of the tidal heat flux, and the melting of the inner material. With the use of this model we introduced the circumplanetary Tidal Temperate Zone (TTZ), that strongly depends on the orbital period of the moon, and less on its radius. We compared the results with the fixed Q model and investigated the statistical volume of the TTZ usi...

  10. Modeling of the Aging Viscoelastic Properties of Cement Paste Using Computational Methods 

    E-Print Network [OSTI]

    Li, Xiaodan

    2012-07-16T23:59:59.000Z

    computational model using finite element method to predict the viscoelastic behavior of cement paste, and using this model, virtual tests can be carried out to improve understanding of the mechanisms of viscoelastic behavior. The primary finding from...

  11. Viscoelastic fluid flow in a 2D channel bounded above by a deformable finite thickness elastic wall

    E-Print Network [OSTI]

    Chakraborty, Debadi

    2015-01-01T23:59:59.000Z

    The steady flow of three viscoelastic fluids (Oldroyd-B, FENE-P, and Owens model for blood) in a two-dimensional channel, partly bound by a deformable, finite thickness neo-Hookean solid, is computed. The limiting Weissenberg number beyond which computations fail to converge is found to increase with increasing dimensionless solid elasticity parameter {\\Gamma}, following the trend Owens > FENE- P > Oldroyd-B. The highly shear thinning nature of Owens model leads to the elastic solid always collapsing into the channel, for the wide range of values of {\\Gamma} considered here. In the case of the FENE-P and Oldroyd-B models, however, the fluid-solid interface can be either within the channel, or bulge outwards, depending on the value of {\\Gamma}. This behaviour differs considerably from predictions of earlier models that treat the deformable solid as a zero-thickness membrane, in which case the membrane always lies within the channel. The capacity of the solid wall to support both pressure and shear stress, in c...

  12. Controlling Deformation in Elastic and Viscoelastic Beams Due to Temperature and Moisture Changes Using Piezoelectric Actuator

    E-Print Network [OSTI]

    Kuravi, Ramachandra Srinivasa Chaitanya

    2012-07-16T23:59:59.000Z

    variables in cases of actuated and unactuated beams. Four materials are chosen for this study; aluminium, epoxy, carbon fiber reinforced polymer with fiber volume fraction of 60 percent, and an epoxy-like viscoelastic material. The viscoelastic material...

  13. Protein viscoelastic dynamics: a model system

    E-Print Network [OSTI]

    Craig Fogle; Joseph Rudnick; David Jasnow

    2015-02-02T23:59:59.000Z

    A model system inspired by recent experiments on the dynamics of a folded protein under the influence of a sinusoidal force is investigated and found to replicate many of the response characteristics of such a system. The essence of the model is a strongly over-damped oscillator described by a harmonic restoring force for small displacements that reversibly yields to stress under sufficiently large displacement. This simple dynamical system also reveals unexpectedly rich behavior, exhibiting a series of dynamical transitions and analogies with equilibrium thermodynamic phase transitions. The effects of noise and of inertia are briefly considered and described.

  14. A Micromechanical Model for Viscoelastic-Viscoplastic Analysis of Particle Reinforced Composite 

    E-Print Network [OSTI]

    Kim, Jeong Sik

    2011-02-22T23:59:59.000Z

    This study introduces a time-dependent micromechanical model for a viscoelastic-viscoplastic analysis of particle-reinforced composite and hybrid composite. The studied particle-reinforced composite consists of solid spherical particle and polymer...

  15. Non-Linear Drying Diffusion and Viscoelastic Drying Shrinkage Modeling in Hardened Cement Pastes

    E-Print Network [OSTI]

    Leung, Chin K.

    2010-07-14T23:59:59.000Z

    modeling with an average diffusion coefficient and with determined viscoelastic parameters from creep tests agreed well compared to the shrinkage data from experiments, indicating that drying shrinkage of cement paste may be considered as a poroviscoelastic...

  16. A Micromechanical Model for Viscoelastic-Viscoplastic Analysis of Particle Reinforced Composite

    E-Print Network [OSTI]

    Kim, Jeong Sik

    2011-02-22T23:59:59.000Z

    This study introduces a time-dependent micromechanical model for a viscoelastic-viscoplastic analysis of particle-reinforced composite and hybrid composite. The studied particle-reinforced composite consists of solid spherical particle and polymer...

  17. Finite Element Modeling of Drilling Using DEFORM

    E-Print Network [OSTI]

    Gardner, Joel D.; Dornfeld, David

    2006-01-01T23:59:59.000Z

    Vijayaraghavan, A. (2005), “Drilling of Fiber- ReinforcedFINITE ELEMENT MODELING OF DRILLING USING DEFORM J. Gardner,of Comprehensive Drilling Simulation Tool” ABSTRACT DEFORM-

  18. A Model of Viscoelastic Ice-Shelf Flexure

    E-Print Network [OSTI]

    MacAyeal, Douglas R.; Sergienko, Olga V.; Banwell, Alison F.

    2015-07-15T23:59:59.000Z

    , and the flow rate constant is B¯ = 108 Pa s1/3. Our choice of Poisson ratio µ is261 based on laboratory measurements [e.g., Jellinek and Brill, 1956] and seismic phase speed estimates262 [e.g., Kirchner and Bentley, 1979] , other studies [e.g Gudmundsson, 2011... meltwater loads accumulate.363 Perhaps the most novel generalization of the interpretation of viscoelastic phenomenon displayed364 in our study is to say that: short-term elastic processes “leak” into long-term viscous behavior.365 Thus, strictly speaking, a...

  19. On Deformable Models for Visual Pattern Recognition

    E-Print Network [OSTI]

    Yeung, Dit-Yan

    deformable models, but some existing 2 1 2 D and 3D deformable models are also briefly reviewed. Potential has been successfully applied to recognize rigid objects, such as machinery parts and printed def (w; H j ; ¯ w), which represents the ``energy'' of the current model with respect to the reference

  20. Analytical Model of Tidal Distortion and Dissipation for a Giant Planet with a Viscoelastic Core

    E-Print Network [OSTI]

    Storch, Natalia I

    2015-01-01T23:59:59.000Z

    We present analytical expressions for the tidal Love numbers of a giant planet with a solid core and a fluid envelope. We model the core as a uniform, incompressible, elastic solid, and the envelope as a non-viscous fluid satisfying the $n=1$ polytropic equation of state. We discuss how the Love numbers depend on the size, density, and shear modulus of the core. We then model the core as a viscoelastic Maxwell solid and compute the tidal dissipation rate in the planet as characterized by the imaginary part of the Love number $k_2$. Our results improve upon existing calculations based on planetary models with a solid core and a uniform ($n=0$) envelope. Our analytical expressions for the Love numbers can be applied to study tidal distortion and viscoelastic dissipation of giant planets with solid cores of various rheological properties, and our general method can be extended to study tidal distortion/dissipation of super-earths.

  1. Modelling Viscoelastic Behaviour of Polymer by A Mixed Velocity, Displacement Formulation - Numerical and Experimental Results

    SciTech Connect (OSTI)

    Pham, VT.; Silva, L.; Digonnet, H.; Combeaud, C.; Billon, N.; Coupez, T. [Centre for Material Forming (CEMEF), MINES ParisTech, Rue Claude Daunesse, Sophia Antipolis cedex (France)

    2011-05-04T23:59:59.000Z

    The objective of this work is to model the viscoelastic behaviour of polymer from the solid state to the liquid state. With this objective, we perform experimental tensile tests and compare with simulation results. The chosen polymer is a PMMA whose behaviour depends on its temperature. The computation simulation is based on Navier-Stokes equations where we propose a mixed finite element method with an interpolation P1+/P1 using displacement (or velocity) and pressure as principal variables. The implemented technique uses a mesh composed of triangles (2D) or tetrahedra (3D). The goal of this approach is to model the viscoelastic behaviour of polymers through a fluid-structure coupling technique with a multiphase approach.

  2. Thermo-Viscoelastic-Viscoplastic-Viscodamage-Healing Modeling of Bituminous Materials: Theory and Computation

    E-Print Network [OSTI]

    Darabi Konartakhteh, Masoud

    2012-10-19T23:59:59.000Z

    ……………… ……… 341 9.6. Extrapolation of the Rutting in 3D.……....………… 348 9.7. Comparison with Experimental Results.….………… 351 9.8. Conclusions………………………………………… 354 xviii CHAPTER Page X CONCLUSIONS AND RECOMMENDATIONS..…………… 356 10... prediction using viscoelastic- viscoplastic model and experimental data for the cyclic stress control test at 19oC when the stress amplitude is 750kPa. (a) Loading cycles 1-30; (b) Loading cycles 970-980……………….. 268 7.36 Comparison of the VE...

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

    SciTech Connect (OSTI)

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

    2012-03-01T23:59:59.000Z

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

  4. Hyperbolic reformulation of a 1D viscoelastic blood flow model and ADER finite volume schemes

    SciTech Connect (OSTI)

    Montecinos, Gino I.; Müller, Lucas O.; Toro, Eleuterio F.

    2014-06-01T23:59:59.000Z

    The applicability of ADER finite volume methods to solve hyperbolic balance laws with stiff source terms in the context of well-balanced and non-conservative schemes is extended to solve a one-dimensional blood flow model for viscoelastic vessels, reformulated as a hyperbolic system, via a relaxation time. A criterion for selecting relaxation times is found and an empirical convergence rate assessment is carried out to support this result. The proposed methodology is validated by applying it to a network of viscoelastic vessels for which experimental and numerical results are available. The agreement between the results obtained in the present paper and those available in the literature is satisfactory. Key features of the present formulation and numerical methodologies, such as accuracy, efficiency and robustness, are fully discussed in the paper.

  5. Two- and Three-Dimensional Microstructural Modeling of Asphalt Particulate Composite Materials using a Unified Viscoelastic-Viscoplastic-Viscodamage Constitutive Model

    E-Print Network [OSTI]

    You, Taesun

    2013-08-13T23:59:59.000Z

    The main objective of this study is to develop and validate a framework for microstructural modeling of asphalt composite materials using a coupled thermo-viscoelastic, thermo-viscoplastic, and thermo-viscodamage constitutive model. In addition...

  6. Deformable Models & Applications Department of Computer Science

    E-Print Network [OSTI]

    Duan, Ye

    Deformable Models & Applications (Part I) Ye Duan Department of Computer Science University of Missouri at Columbia December 21, 2004 Ye Duan Department of Computer Science University of Missouri at Columbia December 21, 2004 University of Missouri at ColumbiaDepartment of Computer Science #12;Department

  7. Modeling of the Aging Viscoelastic Properties of Cement Paste Using Computational Methods

    E-Print Network [OSTI]

    Li, Xiaodan

    2012-07-16T23:59:59.000Z

    1.2 Scope and Problem Statement ................................................ 3 1.3 Tasks ....................................................................................... 4... ............................................................................ 37 4.1.2 Viscoelastic ................................................................... 39 4.1.3 Dissolution...

  8. Spatially resolved measurements of kinematics and flow-induced birefringence in worm-like micellar solutions undergoing high rate deformations

    E-Print Network [OSTI]

    Ober, Thomas J. (Thomas Joseph)

    2010-01-01T23:59:59.000Z

    Worm-like micellar solutions are model non-Newtonian systems on account of their well understood linear viscoelastic behavior. Their high deformation rate, non-linear rheological response, however, remains inadequately ...

  9. RGPS/Model Ice Deformation July 3, 2003 1 Sea Ice Deformation Rates From Satellite Measurements and in a Model

    E-Print Network [OSTI]

    Lindsay, Ron

    of the Arctic geophysical environment. The deformation rate of pack ice, determined from the spatial gradientsRGPS/Model Ice Deformation July 3, 2003 1 Sea Ice Deformation Rates From Satellite Measurements The deformation of sea ice is an important element of the Arctic climate system because of its influence

  10. Competitive Mixture of Deformable Models for Pattern Classification \\Lambda

    E-Print Network [OSTI]

    Yeung, Dit-Yan

    Competitive Mixture of Deformable Models for Pattern Classification \\Lambda Kwok­Wai Cheung Dit to pattern classification. Recently, we have cast a deformable model under a Bayesian framework for classification, giving promising results. However, deformable model methods are computation­ ally expensive due

  11. Modeling the Non-linear Viscoelastic Response of High Temperature Polyimides

    E-Print Network [OSTI]

    Karra, Satish

    2010-01-01T23:59:59.000Z

    A constitutive model is developed to predict the viscoelastic response of polyimide resins that are used in high temperature applications. This model is based on a thermodynamic framework that uses the notion that the `natural configuration' of a body evolves as the body undergoes a process and the evolution is determined by maximizing the rate of entropy production in general and the rate of dissipation within purely mechanical considerations. We constitutively prescribe forms for the specific Helmholtz potential and the rate of dissipation (which is the product of density, temperature and the rate of entropy production), and the model is derived by maximizing the rate of dissipation with the constraint of incompressibility, and the reduced energy dissipation equation is also regarded as a constraint in that it is required to be met in every process that the body undergoes. The efficacy of the model is ascertained by comparing the predictions of the model with the experimental data for PMR-15 and HFPE-II-52 ...

  12. Modeling the Non-linear Viscoelastic Response of High Temperature Polyimides

    E-Print Network [OSTI]

    Satish Karra; K. R. Rajagopal

    2010-08-20T23:59:59.000Z

    A constitutive model is developed to predict the viscoelastic response of polyimide resins that are used in high temperature applications. This model is based on a thermodynamic framework that uses the notion that the `natural configuration' of a body evolves as the body undergoes a process and the evolution is determined by maximizing the rate of entropy production in general and the rate of dissipation within purely mechanical considerations. We constitutively prescribe forms for the specific Helmholtz potential and the rate of dissipation (which is the product of density, temperature and the rate of entropy production), and the model is derived by maximizing the rate of dissipation with the constraint of incompressibility, and the reduced energy dissipation equation is also regarded as a constraint in that it is required to be met in every process that the body undergoes. The efficacy of the model is ascertained by comparing the predictions of the model with the experimental data for PMR-15 and HFPE-II-52 polyimide resins.

  13. 1-D closure models for slender 3-D viscoelastic free jets: von Karman flow geometry and elliptical cross section

    SciTech Connect (OSTI)

    Bechtel, S.E.; Forest, M.G.; Holm, D.D.; Lin, K.J.

    1988-01-01T23:59:59.000Z

    In this paper we derive one space dimensional, reduced systems of equations (1-D closure models) for viscoelastic free jets. We begin with the three-dimensional system of conservation laws and a Maxwell-Jeffreys constitutive law for an incompressible viscoelastic fluid. First, we exhibit exact truncations to a finite, closed system of 1-D equations based on classical velocity assumptions of von Karman. Next, we demonstrate that the 3-D free surface boundary conditions overconstrain these truncated systems, so that only a very limited class of solutions exist. We then proceed to derive approximate 1-D closure theories through a slender jet asymptotic scaling, combined with appropriate definitions of velocity, pressure and stress unknowns. Our nonaxisymmetric 1-D slender jet models incorporate the physical effects of inertia, viscoelasticity (viscosity, relaxation and retardation), gravity, surface tension, and properties of the ambient fluid, and include shear stresses and time dependence. Previous special 1-D slender jet models correspond to the lowest order equations in the present asymptotic theory by an a posteriori suppression to leading order of some of these effects, and a reduction to axisymmetry. Solutions of the lowest order system of equations in this asymptotic analysis are presented: For the special cases of elliptical inviscid and Newtonian free jets, subject to the effects of surface tension and gravity, our model predicts oscillation of the major axis of the free surface elliptical cross section between perpendicular directions with distance down the jet, and drawdown of the cross section, in agreement with observed behavior. 15 refs.

  14. Stability analysis of a viscoelastic model for ion-irradiated silicon

    E-Print Network [OSTI]

    Scott A. Norris

    2012-01-12T23:59:59.000Z

    To study the effect of stress within the thin amorphous film generated atop Si irradiated by Ar+, we model the film as a viscoelastic medium into which the ion beam continually injects biaxial compressive stress. We find that at normal incidence, the model predicts a steady compressive stress of a magnitude comparable to experiment. However, linear stability analysis at normal incidence reveals that this mechanism of stress generation is unconditionally stabilizing due to a purely kinematic material flow, depending on none of the material parameters. Thus, despite plausible conjectures in the literature as to its potential role in pattern formation, we conclude that beam stress at normal incidence is unlikely to be a source of instability at any energy, supporting recent theories attributing hexagonal ordered dots to the effects of composition. In addition, we find that the elastic moduli appear in neither the steady film stress nor the leading order smoothening, suggesting that the primary effects of stress can be captured even if elasticity is neglected. This should greatly simplify future analytical studies of highly nonplanar surface evolution, in which the beam-injected stress is considered to be an important effect.

  15. Viscoelastic effects on frequency tuning of a dielectric elastomer membrane resonator

    SciTech Connect (OSTI)

    Zhou, Jianyou; Jiang, Liying, E-mail: lyjiang@eng.uwo.ca; Khayat, Roger E. [Department of Mechanical and Materials Engineering, The University of Western Ontario, London, Ontario N6A 5B9 (Canada)

    2014-03-28T23:59:59.000Z

    As a recent application of dielectric elastomers (DEs), DE resonators have become an alternative to conventional silicon-based resonators used in MEMS and have attracted much interest from the research community. However, most existing modeling works for the DE resonators ignore the intrinsic viscoelastic effect of the material that may strongly influence their dynamic performance. Based on the finite-deformation viscoelasticity theory for dielectrics, this paper theoretically examines the in-plane oscillation of a DE membrane resonator to demonstrate how the material viscoelasticity affects the actuation and frequency tuning processes of the resonator. From the simulation results, it is concluded that not only the applied voltage can change the natural frequency of the resonator, but also the inelastic deformation contributes to frequency tuning. Due to the viscoelasticity of the material, the electrical loading rate influences the actuation process of the DE resonator, while it has little effect on the final steady frequency tuned by the prescribed voltage within the safety range. With the consideration of the typical failure modes of the resonator and the evolution process of the material, the tunable frequency range and the safe range of the applied voltage of the DE membrane resonator with different dimension parameters are determined in this work, which are found to be dependent on the electrical loading rate. This work is expected to provide a better understanding on the frequency tuning of viscoelastic DE membrane resonators and a guideline for the design of DE devices.

  16. Detection of Cardiac Occlusions Using Viscoelastic Wave Propagation

    E-Print Network [OSTI]

    Detection of Cardiac Occlusions Using Viscoelastic Wave Propagation H.T. Banks and J. R. Samuels driven viscoelastic (VE) waves propagated through biotissue to body surface sensors. We in- vestigate: Inverse problems, viscoelastic models, wave propagation in biotissue, statistical models. AMS Subject

  17. A Four-Dimensional Viscoelastic Deformation Model For Long Valley Caldera,

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnualProperty Edit withTianlinPapersWindey Wind6:00-06:00 U.S. NationalMammals JumpMt-5-Ex |

  18. Nonlinear viscoelastic characterization of thin films using dynamic mechanical analysis 

    E-Print Network [OSTI]

    Payne, Debbie Flowers

    1993-01-01T23:59:59.000Z

    manner similar to the traditional time temperature superposition principle for linear viscoelastic materials where stress systematically compresses or expands the time scale. From dynamic mechanical testing and analysis, the experimental viscoelastic.... D. Nonlinear Characterization of Thin Film Materials. . . . Nonlinear Viscoelastic Models . Dynamic Mechanical Testing. Summary of Literature Reviewed. 5 5 7 8 III THEORETICAL ANALYSIS . A. B. C. D. Conversion of Experimental Values...

  19. Coefficient of restitution for viscoelastic disks

    E-Print Network [OSTI]

    Thomas Schwager

    2007-01-08T23:59:59.000Z

    The dissipative collision of two identical viscoelastic disks is studied. By using a known law for the elastic part of the interaction force and the viscoelastic damping model an analytical solution for the coefficient of restitution shall be given. The coefficient of restitution depends significantly on the impact velocity. It approaches one for small velocities and decreases for increasing velocities.

  20. Relativistic Hartree-Fock-Bogoliubov model for deformed nuclei

    SciTech Connect (OSTI)

    Ebran, J.-P.; Khan, E.; Pena Arteaga, D. [Institut de Physique Nucleaire, Universite Paris-Sud, IN2P3-CNRS, FR-91406 Orsay Cedex (France); Vretenar, D. [Physics Department, Faculty of Science, University of Zagreb, HR-10000 Zagreb (Croatia)

    2011-06-15T23:59:59.000Z

    The relativistic Hartree-Fock-Bogoliubov model for axially deformed nuclei (RHFBz) is introduced. The model is based on an effective Lagrangian with density-dependent meson-nucleon couplings in the particle-hole channel, and the central part of the Gogny force is used in the pairing channel. The RHFBz quasiparticle equations are solved by expansion in the basis of a deformed harmonic oscillator. Illustrative RHFBz calculations are performed for carbon, neon, and magnesium isotopes. The effect of explicitly including the pion field is investigated for binding energies, deformation parameters, and charge radii and has an impact on the nuclei's shape.

  1. A Probabilistic Deformation Demand Model and Fragility Estimates for Asymmetric Offshore Jacket Platforms

    E-Print Network [OSTI]

    Fallon, Michael Brooks

    2012-11-12T23:59:59.000Z

    to assess the deformation demand on asymmetric offshore jacket platforms subject to wave and current loadings. The probabilistic model is constructed by adding correction terms and a model error to an existing deterministic deformation demand model...

  2. Asphalt Pavement Aging and Temperature Dependent Properties through a Functionally Graded Viscoelastic Model, Part-II: Applications

    E-Print Network [OSTI]

    Paulino, Glaucio H.

    Asphalt Pavement Aging and Temperature Dependent Properties through a Functionally Graded simulation of functionally graded viscoelastic properties in asphalt concrete pavements. The techniques properties. A full-depth asphalt concrete pavement has been simulated to demonstrate the applicability

  3. Homogenization of a Multiscale Viscoelastic Model with Nonlocal Damping, Application to the Human Lungs

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Lungs PAUL CAZEAUX, Laboratoire J.­L. Lions, UMR 7598, Université Pierre et Marie Curie-Paris 6, 4 Place of the deformation of the human lung tissue, called the lung parenchyma, during the respiration process bronchi and enters the lungs. It is then distributed by the bronchial tree to the acini or alveolar

  4. MULTISCALE MODELING OF DIFFUSION-INDUCED DEFORMATION PROCESSES

    E-Print Network [OSTI]

    Ponce, V. Miguel

    MULTISCALE MODELING OF DIFFUSION- INDUCED DEFORMATION PROCESSES Dr. Eugene Olevsky Friday, February 19, 2010 Engineering Bldg. Room E 300 Sintering is a high temperature process of bonding together of matter transport by different diffusion mechanisms driven by the high surface energy of aggregates

  5. Hereditary kernel identification method of nonlinear polymeric viscoelastic materials

    E-Print Network [OSTI]

    Olodo Emmanuel; Villevo Adanhounme; Mahouton Norbert Hounkonnou

    2012-12-26T23:59:59.000Z

    This paper deals with a polymeric matrix composite material. The matrix behaviour is described by the modified Rabotnov's nonlinear viscoelastic model assuming the material is nonlinear viscoelastic. The parameters of creep and stress-relaxation kernels of the model are determined. From the experimental data related to kernels approximated by spline functions and by means of the method of weighted residual, the formulas for the determination of viscoelastic parameters are derived.

  6. Dynamics and Stability of Rolling Viscoelastic Tires

    SciTech Connect (OSTI)

    Potter, Trevor

    2013-04-30T23:59:59.000Z

    Current steady state rolling tire calculations often do not include treads because treads destroy the rotational symmetry of the tire. We describe two methodologies to compute time periodic solutions of a two-dimensional viscoelastic tire with treads: solving a minimization problem and solving a system of equations. We also expand on work by Oden and Lin on free spinning rolling elastic tires in which they disovered a hierachy of N-peak steady state standing wave solutions. In addition to discovering a two-dimensional hierarchy of standing wave solutions that includes their N-peak hiearchy, we consider the eects of viscoelasticity on the standing wave solutions. Finally, a commonplace model of viscoelasticity used in our numerical experiments led to non-physical elastic energy growth for large tire speeds. We show that a viscoelastic model of Govindjee and Reese remedies the problem.

  7. Characterization of viscoelastic properties of submarine sediments

    E-Print Network [OSTI]

    King, Jim Bob

    1975-01-01T23:59:59.000Z

    simplified, it is sufficient for the intent of this discussion. From this simplified model of clay structure some of the factors affecting the viscoelastic nature of submarine clays can be identified. When the flocculent clay structure is first subjected... 1975 Major Subject: Civil Engineering CHARACTERIZATION OF VISCOELASTIC PROPERTIES OF SUBMARINE SEDIMENTS A Thesis by Jim Bob King Approved as to sty1e and content by: Chair an of Commi tee Head of Department Member Member December 1975...

  8. CONSTITUTIVE MODELLING OF SHAPE MEMORY ALLOYS AND UPSCALING OF DEFORMABLE POROUS MEDIA

    E-Print Network [OSTI]

    Popov, Peter

    : Aerospace Engineering #12;CONSTITUTIVE MODELLING OF SHAPE MEMORY ALLOYS AND UPSCALING OF DEFORMABLE POROUSCONSTITUTIVE MODELLING OF SHAPE MEMORY ALLOYS AND UPSCALING OF DEFORMABLE POROUS MEDIA. Reed (Head of Department) May 2005 Major Subject: Aerospace Engineering #12;iii ABSTRACT Constitutive

  9. Modeling of friction-induced deformation and microstructures.

    SciTech Connect (OSTI)

    Michael, Joseph Richard; Prasad, Somuri V.; Jungk, John Michael; Cordill, Megan J. (University of Minnesota); Bammann, Douglas J.; Battaile, Corbett Chandler; Moody, Neville Reid; Majumdar, Bhaskar Sinha (New Mexico Institure of Mining and Technology)

    2006-12-01T23:59:59.000Z

    Frictional contact results in surface and subsurface damage that could influence the performance, aging, and reliability of moving mechanical assemblies. Changes in surface roughness, hardness, grain size and texture often occur during the initial run-in period, resulting in the evolution of subsurface layers with characteristic microstructural features that are different from those of the bulk. The objective of this LDRD funded research was to model friction-induced microstructures. In order to accomplish this objective, novel experimental techniques were developed to make friction measurements on single crystal surfaces along specific crystallographic surfaces. Focused ion beam techniques were used to prepare cross-sections of wear scars, and electron backscattered diffraction (EBSD) and TEM to understand the deformation, orientation changes, and recrystallization that are associated with sliding wear. The extent of subsurface deformation and the coefficient of friction were strongly dependent on the crystal orientation. These experimental observations and insights were used to develop and validate phenomenological models. A phenomenological model was developed to elucidate the relationships between deformation, microstructure formation, and friction during wear. The contact mechanics problem was described by well-known mathematical solutions for the stresses during sliding friction. Crystal plasticity theory was used to describe the evolution of dislocation content in the worn material, which in turn provided an estimate of the characteristic microstructural feature size as a function of the imposed strain. An analysis of grain boundary sliding in ultra-fine-grained material provided a mechanism for lubrication, and model predictions of the contribution of grain boundary sliding (relative to plastic deformation) to lubrication were in good qualitative agreement with experimental evidence. A nanomechanics-based approach has been developed for characterizing the mechanical response of wear surfaces. Coatings are often required to mitigate friction and wear. Amongst other factors, plastic deformation of the substrate determines the coating-substrate interface reliability. Finite element modeling has been applied to predict the plastic deformation for the specific case of diamond-like carbon (DLC) coated Ni alloy substrates.

  10. A Mechanism-based Model for Deformation Twinning in Polycrystalline...

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

    in Polycrystalline FCC Steel. Abstract: Deformation twinning, a common and important plastic deformation mechanism, is the key contributor to the excellent combination of...

  11. INTERACTIVE MODELLING OF MPEG-4 DEFORMABLE HUMAN BODY MODELS

    E-Print Network [OSTI]

    Cordier, Frederic

    years, human characters have become more and more important in computer animation, virtual reality that are immediately usable for animation. In doing so, we aim to carry out realistic deformations on the human body that encompasses addition of props, face and body animation, coordination along with stages or virtual environments

  12. Winding vacuum energies in a deformed O(4) sigma model

    E-Print Network [OSTI]

    Vladimir V. Bazhanov; Gleb A. Kotousov; Sergei L. Lukyanov

    2014-09-01T23:59:59.000Z

    We consider the problem of calculating the Casimir energies in the winding sectors of Fateev's SS-model, which is an integrable two-parameter deformation of the O(4) non-linear sigma model in two dimensions. This problem lies beyond the scope of all traditional methods of integrable quantum field theory including the thermodynamic Bethe ansatz and non-linear integral equations. Here we propose a solution based on a remarkable correspondence between classical and quantum integrable systems and express the winding energies in terms of certain solutions of the classical sinh-Gordon equation.

  13. Deformed Bose gas models aimed at taking into account both compositeness of particles and their interaction

    E-Print Network [OSTI]

    Gavrilik, A M

    2013-01-01T23:59:59.000Z

    We consider the deformed Bose gas model with the deformation structure function that is the combination of a q-deformation and a quadratically polynomial deformation. Such a choice of the unifying deformation structure function enables us to describe the interacting gas of composite (two-fermionic or two-bosonic) bosons. Using the relevant generalization of the Jackson derivative, we derive a two-parametric expression for the total number of particles, from which the deformed virial expansion of the equation of state is obtained. The latter is interpreted as the virial expansion for the effective description of a gas of interacting composite bosons with some interaction potential.

  14. Efficient modelling of particle collisions using a non-linear viscoelastic contact force

    E-Print Network [OSTI]

    Shouryya Ray; Tobias Kempe; Jochen Fröhlich

    2015-02-26T23:59:59.000Z

    In this paper the normal collision of spherical particles is investigated. The particle interaction is modelled in a macroscopic way using the Hertzian contact force with additional linear damping. The goal of the work is to develop an efficient approximate solution of sufficient accuracy for this problem which can be used in soft-sphere collision models for Discrete Element Methods and for particle transport in viscous fluids. First, by the choice of appropriate units, the number of governing parameters of the collision process is reduced to one, thus providing a dimensionless parameter that characterizes all such collisions up to dynamic similitude. It is a simple combination of known material parameters as well as initial conditions. A rigorous calculation of the collision time and restitution coefficient from the governing equations, in the form of a series expansion in this parameter is provided. Such a first principles calculation is particularly interesting from a theoretical perspective. Since the governing equations present some technical difficulties, the methods employed are also of interest from the point of view of the analytical technique. Using further approximations, compact expressions for the restitution coefficient and the collision time are then provided. These are used to implement an approximate algebraic rule for computing the desired stiffness and damping in the framework of the adaptive collision model (Kempe & Fr\\"ohlich, J. Fluid Mech., 709: 445-489, 2012). Numerical tests with binary as well as multiple particle collisions are included that illustrate the accuracy of the proposed method and its superiority in terms of numerical efficiency.

  15. Modeling level structures of odd-odd deformed nuclei

    SciTech Connect (OSTI)

    Hoff, R.W.; Kern, J.; Piepenbring, R.; Boisson, J.P.

    1984-09-07T23:59:59.000Z

    A technique for modeling quasiparticle excitation energies and rotational parameters in odd-odd deformed nuclei has been applied to actinide species where new experimental data have been obtained by use of neutron-capture gamma-ray spectroscopy. The input parameters required for the calculation were derived from empirical data on single-particle excitations in neighboring odd-mass nuclei. Calculated configuration-specific values for the Gallagher-Moszkowski splittings were used. Calculated and experimental level structures for /sup 238/Np, /sup 244/Am, and /sup 250/Bk are compared, as well as those for several nuclei in the rare-earth region. The agreement for the actinide species is excellent, with bandhead energies deviating 22 keV and rotational parameters 5%, on the average. Corresponding average deviations for five rare-earth nuclei are 47 keV and 7%. Several applications of this modeling technique are discussed. 18 refs., 5 figs., 4 tabs.

  16. Seismic viscoelastic attenuation Submitted to

    E-Print Network [OSTI]

    Cormier, Vernon F.

    Seismic viscoelastic attenuation Submitted to: Encyclopedia of Solid Earth Geophysics Harsh Gupta-3046 USA E-mail: vernon.cormier@uconn.edu Tel: 860-486-3547 Fax: 860-486-3346 #12;SEISMIC VISCOELASTIC ATTENUATION Synonyms Seismic intrinsic attenuation Definitions Linear viscoelastic attenuation. The loss

  17. Modeling Attractor Deformation in the Rodent Head-Direction JEREMY P. GOODRIDGE1

    E-Print Network [OSTI]

    Touretzky, David S.

    Modeling Attractor Deformation in the Rodent Head-Direction System JEREMY P. GOODRIDGE1 AND DAVID S attractor deformation in the rodent head-direction system. J Neurophysiol 83: 3402­3410, 2000. We present a model of the head-direction circuit in the rat that improves on earlier models in several respects

  18. Thermodynamics of viscoelastic fluids: the temperature equation.

    E-Print Network [OSTI]

    Wapperom, Peter

    Thermodynamics of viscoelastic fluids: the temperature equation. Peter Wapperom Martien A. Hulsen and Hydrodynamics Rotterdamseweg 145 2628 AL Delft (The Netherlands) Abstract From the thermodynamics with internal. The well- known stress differential models that fit into the thermodynamic theory will be treated

  19. A Deformable Model for Bringing Particles in Anders Lindbjerg Dahl1

    E-Print Network [OSTI]

    Dahl, Anders Lindbjerg

    about particle distribution, size and shape, and these parameters are often essential for system designA Deformable Model for Bringing Particles in Focus Anders Lindbjerg Dahl1 , Thomas Martini Abstract. We provide a deformable model for particle analysis. We in- vestigate particle images from

  20. Improved crystallographic models through iterated local density-guided model deformation and reciprocal-space refinement

    SciTech Connect (OSTI)

    Terwilliger, Thomas C., E-mail: terwilliger@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Read, Randy J. [University of Cambridge, Cambridge CB2 0XY (United Kingdom); Adams, Paul D. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Building 64R0121, Berkeley, CA 94720 (United States); Brunger, Axel T. [Stanford University, 318 Campus Drive West, Stanford, CA 94305-5432 (United States); Afonine, Pavel V.; Grosse-Kunstleve, Ralf W. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Building 64R0121, Berkeley, CA 94720 (United States); Hung, Li-Wei [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2012-07-01T23:59:59.000Z

    A density-based procedure is described for improving a homology model that is locally accurate but differs globally. The model is deformed to match the map and refined, yielding an improved starting point for density modification and further model-building. An approach is presented for addressing the challenge of model rebuilding after molecular replacement in cases where the placed template is very different from the structure to be determined. The approach takes advantage of the observation that a template and target structure may have local structures that can be superimposed much more closely than can their complete structures. A density-guided procedure for deformation of a properly placed template is introduced. A shift in the coordinates of each residue in the structure is calculated based on optimizing the match of model density within a 6 Å radius of the center of that residue with a prime-and-switch electron-density map. The shifts are smoothed and applied to the atoms in each residue, leading to local deformation of the template that improves the match of map and model. The model is then refined to improve the geometry and the fit of model to the structure-factor data. A new map is then calculated and the process is repeated until convergence. The procedure can extend the routine applicability of automated molecular replacement, model building and refinement to search models with over 2 Å r.m.s.d. representing 65–100% of the structure.

  1. WAVE SPEEDS FOR AN ELASTOPLASTIC MODEL FOR TWODIMENSIONAL DEFORMATIONS WITH A NONASSOCIATIVE FLOW RULE

    E-Print Network [OSTI]

    WAVE SPEEDS FOR AN ELASTOPLASTIC MODEL FOR TWO­DIMENSIONAL DEFORMATIONS WITH A NON­ASSOCIATIVE FLOW of variables, the character­ istic speeds of plane wave solutions of the system are computed. For both plastic and elastic deformations, there are two nonzero wave speeds, referred to as fast and slow waves. It is shown

  2. Deformable model for 3D intramodal nonrigid breast image registration with fiducial skin markers

    E-Print Network [OSTI]

    of FSM, finite element method (FEM) is used to distribute the markers' displacements linearly over with rigid registration technique. Keywords: Intramodal image registration, finite element method, deformable, we developed a finite element method (FEM) deformable breast model to correct motion artifacts

  3. Kinematic models of interseismic deformation in Southern California

    E-Print Network [OSTI]

    Meade, Brendan J. (Brendan Joseph), 1975-

    2004-01-01T23:59:59.000Z

    We develop a framework for interpreting geodetic measurements of interseismic deformation and geologic slip rate estimates in terms of block motions. This method accounts for the effects of block rotations and interseismic ...

  4. Author's personal copy Interpretation of interseismic deformations and the seismic cycle associated with

    E-Print Network [OSTI]

    Vigny, Christophe

    Author's personal copy Interpretation of interseismic deformations and the seismic cycle associated online 11 January 2013 Keywords: Seismic cycle Finite element Subduction Earthquake Viscoelastic asthenosphere Low viscosity wedge The deformations of the overriding and subducting plates during the seismic

  5. Vane shear determination of the visco-elastic shear modulus of submarine sediments

    E-Print Network [OSTI]

    Stevenson, Herbert Scott

    1973-01-01T23:59:59.000Z

    the process of deformation under shear can be considered and some of the factors affecting the viscoelastic nature of submarine clays can be identified. When the flocculent clay structure is subjected to shear the bonds between the particles ai e first... of MASTER OF SCIENCE December 1973 Major Subject: Civil Engineering VANE SHEAR DETERMINATION OF THE VISCOELASTIC SHEAR MODULUS OF SUBMARINE SEDIMENTS A Thesis by Herbert Scott Stevenson Approved as to style and content by: Chairman of Committ e M...

  6. (Non)renormalizability of the D-deformed Wess-Zumino model

    SciTech Connect (OSTI)

    Dimitrijevic, Marija [INFN Gruppo collegato di Alessandria, Via Bellini 25/G, 15100 Alessandria (Italy); University of Belgrade, Faculty of Physics Studentski trg 12, 11000 Beograd (Serbia); Nikolic, Biljana; Radovanovic, Voja [University of Belgrade, Faculty of Physics Studentski trg 12, 11000 Beograd (Serbia)

    2010-05-15T23:59:59.000Z

    We continue the analysis of the D-deformed Wess-Zumino model that we introduced in M. Dmitrijevic and V. Radovanovic, J. High Energy Phys. 04 (2009) 108. The model is defined by a deformation that is non-Hermitian and given in terms of the covariant derivatives D{sub {alpha}.} We calculate one-loop divergences in the two-point, three-point, and four-point Green functions. Possibilities to render the model renormalizable are discussed.

  7. Coupled fluid flow and geomechanical deformation modeling Susan E. Minkoff a,*, C. Mike Stoneb,1

    E-Print Network [OSTI]

    Minkoff, Susan E.

    Coupled fluid flow and geomechanical deformation modeling Susan E. Minkoff a,*, C. Mike Stoneb,1 reservoir properties. Pore pressures from flow are used as loads for the geomechanics code

  8. A framework for comparing geomechanical models of InSAR-measured surface deformation

    E-Print Network [OSTI]

    De Laplante, Neil Edward James

    2011-01-01T23:59:59.000Z

    High-quality Interferometric Synthetic Aperture Radar (InSAR) surface deformation data for field sites around the world has become widely available over the past decade. Geomechanical models based on InSAR data occur ...

  9. Scale model seismicity: a detailed study of deformation localisation from laboratory acoustic emission data 

    E-Print Network [OSTI]

    Graham, Caroline C.

    2010-01-01T23:59:59.000Z

    Acoustic emissions (AE) can provide information relating to the internal state of a deforming rock sample during laboratory testing and have been utilised to quantify damage progression for time-dependent failure modeling. ...

  10. Analysis of viscoelastic soft dielectric elastomer generators operating in an electrical circuit

    E-Print Network [OSTI]

    Eliana Bortot; Ralf Denzer; Andreas Menzel; Massimiliano Gei

    2014-11-13T23:59:59.000Z

    A predicting model for soft Dielectric Elastomer Generators (DEGs) must consider a realistic model of the electromechanical behaviour of the elastomer filling, the variable capacitor and of the electrical circuit connecting all elements of the device. In this paper such an objective is achieved by proposing a complete framework for reliable simulations of soft energy harvesters. In particular, a simple electrical circuit is realised by connecting the capacitor, stretched periodically by a source of mechanical work, in parallel with a battery through a diode and with an electrical load consuming the energy produced. The electrical model comprises resistances simulating the effect of the electrodes and of the conductivity current invariably present through the dielectric film. As these devices undergo a high number of electro-mechanical loading cycles at large deformation, the time-dependent response of the material must be taken into account as it strongly affects the generator outcome. To this end, the viscoelastic behaviour of the polymer and the possible change of permittivity with strains are analysed carefully by means of a proposed coupled electro-viscoelastic constitutive model, calibrated on experimental data available in the literature for an incompressible polyacrilate elastomer (3M VHB4910). Numerical results showing the importance of time-dependent behaviour on the evaluation of performance of DEGs for different loading conditions, namely equi-biaxial and uniaxial, are reported in the final section.

  11. Viscoelastic properties of seed cotton and their effect on module shape and density

    E-Print Network [OSTI]

    Hardin, Robert Glen

    2004-11-15T23:59:59.000Z

    . ............................. 14 3 Peleg's viscoelastic model..............................................................................15 4 Viscoelastic model developed by Bilanski and Graham.................................. 18 5 Stress-strain curve of a work... of harvesting method-loading density tests..................................................... 34 4 Least-squares means for creep response of different loading densities............ 35 5 Least-squares means for creep response of different harvesting methods...

  12. Deformation of the UI-14at%Nb shape memory alloy: experiments and modeling

    SciTech Connect (OSTI)

    Field, Robert D [Los Alamos National Laboratory; Tome, Carlos N [Los Alamos National Laboratory; Mc Cabe, Rodney J [Los Alamos National Laboratory; Clarke, Amy J [Los Alamos National Laboratory; Brown, Donald W [Los Alamos National Laboratory; Tupper, Catherine N [Los Alamos National Laboratory

    2010-12-22T23:59:59.000Z

    U-14at%Nb is a shape memory effect (SME) alloy that undergoes deformation by the motion of complex twins and twin related lath boundaries up to the limit of SME deformation ({approx}7%). All of the twins present in the as-transformed martensite and active during SME deformation are derived from those of the orthorhombic alpha-U phase, modified for the monoclinic distortion of the alpha martensite phase. In the SME regime a simple Bain strain model qualitatively predicts variant selection, texture development in polycrystalline samples, and stress-strain behavior as a function of parent phase orientation in single crystal micropillars. In the post-SME regime, unrecoverable deformation occurs by a combination of slip and twinning, with the first few percent of strain in tension apparently governed by a twin species specifically associated with the monoclinic distortion (i.e. not present in the orthorhombic alpha-U phase). The situation in compression is more complicated, with a combination of slip and twinning systems believed responsible for deformation. A review of the Bain strain model for SME deformation will be presented in conjunction with experimental data. In addition, results from modeling of post-SME behavior using the Visco-Plastic Self-Consistent (VPSC) model will be compared to experimental texture measurements.

  13. Modeling for deformable mirrors and the adaptive optics optimization program

    SciTech Connect (OSTI)

    Henesian, M.A.; Haney, S.W.; Trenholme, J.B. [Lawrence Livermore National Lab., CA (United States); Thomas, M. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center

    1997-03-18T23:59:59.000Z

    We discuss aspects of adaptive optics optimization for large fusion laser systems such as the 192-arm National Ignition Facility (NIF) at LLNL. By way of example, we considered the discrete actuator deformable mirror and Hartmann sensor system used on the Beamlet laser. Beamlet is a single-aperture prototype of the 11-0-5 slab amplifier design for NIF, and so we expect similar optical distortion levels and deformable mirror correction requirements. We are now in the process of developing a numerically efficient object oriented C++ language implementation of our adaptive optics and wavefront sensor code, but this code is not yet operational. Results are based instead on the prototype algorithms, coded-up in an interpreted array processing computer language.

  14. Pumping viscoelastic two-fluid media

    E-Print Network [OSTI]

    Hirofumi Wada

    2010-04-08T23:59:59.000Z

    Using a two-fluid model for viscoelastic polymer solutions, we study analytically fluid transport driven by a transverse, small amplitude traveling wave propagation. The pumping flow far from the waving boundary is shown to be strongly wave number and viscosity dependent, in contrast to a viscous Newtonian fluid. We find the two qualitatively different regimes: In one regime relevant to small wave numbers, the fluidic transport is almost the same as the Newtonian case, and uniform viscoelastic constitutive equations provide a good approximation. In the other regime, the pumping is substantially decreased because of the gel-like character. The boundary separating these two regimes is clarified. Our results suggest possible needs of two-fluid descriptions for the transport and locomotion in biological fluids with cilia and flagella.

  15. Semiclassical origin of anomalous shell effect for tetrahedral deformation in radial power-law potential model

    E-Print Network [OSTI]

    Ken-ichiro Arita; Yasunori Mukumoto

    2014-05-09T23:59:59.000Z

    Shell structures in single-particle energy spectra are investigated against regular tetrahedral type deformation using radial power-law potential model. Employing a natural way of shape parametrization which interpolates sphere and regular tetrahedron, we find prominent shell effects at rather large tetrahedral deformations, which bring about shell energies much larger than the cases of spherical and quadrupole type shapes. We discuss the semiclassical origin of these anomalous shell structures using periodic orbit theory.

  16. Viscoelastic contact mechanics between randomly rough surfaces

    E-Print Network [OSTI]

    Michele Scaraggi; Bo N. J. Persson

    2014-06-27T23:59:59.000Z

    We present exact numerical results for the friction force and the contact area for a viscoelastic solid (rubber) in sliding contact with hard, randomly rough substrates. The rough surfaces are self-affine fractal with roughness over several decades in length scales. We calculate the contribution to the friction from the pulsating deformations induced by the substrate asperities. We also calculate how the area of real contact, $A(v,p) $, depends on the sliding speed $v$ and on the nominal contact pressure $p$, and we show how the contact area for any sliding speed can be obtained from a universal master curve $A(p)$. The numerical results are found to be in good agreement with the predictions of an analytical contact mechanics theory.

  17. Thermo-mechanical modelling of Black Sea Basin (de)formation S. Cloetingh*, G. Spadini1

    E-Print Network [OSTI]

    Beekman, Fred

    Thermo-mechanical modelling of Black Sea Basin (de)formation S. Cloetingh*, G. Spadini1 , J.D. Van; received in revised form 7 January 2002; accepted 19 July 2002 Abstract We present the results of a thermo by rifting and subsequent sediment loading. Thermo-mechanical modelling of integrated lithospheric strength

  18. MetaMorphs: Deformable Shape and Texture Models Xiaolei Huang, Dimitris Metaxas, Ting Chen

    E-Print Network [OSTI]

    dimensional space of distance transforms. The interior texture is captured using a nonparametric kernel-based approximation of the inten- sity probability density function (p.d.f.) inside the model. The deformations. We demonstrate the power of our new models to segmentation applications, and vari- ous examples

  19. Using Nanotechnology in Viscoelastic Surfactant Stimulation Fluids

    E-Print Network [OSTI]

    Gurluk, Merve Rabia 1986-

    2012-11-12T23:59:59.000Z

    Viscoelastic surfactant (VES) fluids are preferred for many applications in the oil industry. Their viscoelastic behavior is due to the overlap and entanglement of very long wormlike micelles. The growth of these wormlike micelles depends...

  20. IEEE TRANSACTIONS ON ROBOTICS, VOL. 26, NO. 5, OCTOBER 2010 837 Modeling Deformations of General Parametric

    E-Print Network [OSTI]

    Jia, Yan-Bin

    IEEE TRANSACTIONS ON ROBOTICS, VOL. 26, NO. 5, OCTOBER 2010 837 Modeling Deformations of General Parametric Shells Grasped by a Robot Hand Jiang Tian and Yan-Bin Jia, Member, IEEE Abstract--The robot hand and normal of the contact area. Design and analysis of a manipulation strategy thus depend on reliable

  1. Numerical models of caldera deformation: Effects of multiphase and multicomponent hydrothermal fluid flow

    E-Print Network [OSTI]

    Numerical models of caldera deformation: Effects of multiphase and multicomponent hydrothermal studies addressing the effects of multiphase flow on crustal mechanics have been attempted. Recent numerical simulations of multiphase (liquid-gas), multicomponent (H2O­CO2) hydrothermal fluid flow

  2. Modeling the electrical resistivity of deformation processed metal-metal composites

    SciTech Connect (OSTI)

    Tian, Liang [Ames Laboratory; Anderson, Iver [Ames Laboratory; Riedemann, Trevor [Ames Laboratory; Russell, Alan [Ames Laboratory

    2014-09-01T23:59:59.000Z

    Deformation processed metal–metal (matrix–reinforcement) composites (DMMCs) are high-strength, high-conductivity in situ composites produced by severe plastic deformation. The electrical resistivity of DMMCs is rarely investigated mechanistically and tends to be slightly higher than the rule-of-mixtures prediction. In this paper, we analyze several possible physical mechanisms (i.e. phonons, interfaces, mutual solution, grain boundaries, dislocations) responsible for the electrical resistivity of DMMC systems and how these mechanisms could be affected by processing conditions (i.e. temperature, deformation processing). As an innovation, we identified and assembled the major scattering mechanisms for specific DMMC systems and modeled their electrical resistivity in combination. From this analysis, it appears that filament coarsening rather than dislocation annihilation is primarily responsible for the resistivity drop observed in these materials after annealing and that grain boundary scattering contributes to the resistivity at least at the same magnitude as does interface scattering.

  3. Deformations of Quantum Field Theories and the Construction of Interacting Models

    E-Print Network [OSTI]

    Sabina Alazzawi

    2015-03-03T23:59:59.000Z

    The subject of this thesis is the rigorous construction of QFT models with nontrivial interaction. Two different approaches in the framework of AQFT are discussed. On the one hand, an inverse scattering problem is considered. A given factorizing S-matrix is thereby taken as the starting point of the construction. The particle spectrum taken into account involves an arbitrary number of massive particle species, transforming under a global gauge group. Starting from known wedge-local auxiliary fields, the transition to local theories is shown. To his end, we make use of the modular nuclearity condition and investigate certain maps from the wedge algebras, generated by the auxiliary fields, to the considered Hilbert space. Under a very plausible conjecture it is shown that these maps are nuclear, which implies the nontriviality of algebras associated with bounded regions in the sense that the Reeh-Schlieder property holds. A large class of integrable models with factorizing S-matrices in 1+1 dimensions can be constructed in this way. Among them are the O(N)-invariant nonlinear sigma-models. Deformation techniques, on the other hand, constitute a method of construction which may be applied in arbitrary spacetime dimensions. This approach starts from a known quantum field theoretic model which is subjected to a certain modification. Here, concretely, the model of a scalar massive Fermion was deformed. The emerging models are based on wedge-local fields, allowing for the computation of the two-particle S-matrix. The resulting scattering matrix depends on the deformation and differs from the one of the initial model. By restricting to 1+1 dimensions, the deformation method yields a large class of integrable models with factorizing S-matrices, including the Sinh-Gordon model.

  4. Wave propagation in anisotropic viscoelasticity

    E-Print Network [OSTI]

    Andrzej Hanyga

    2015-04-30T23:59:59.000Z

    We extend the theory of complete Bernstein functions to matrix-valued functions and apply it to analyze Green's function of an anisotropic multi-dimension\\-al linear viscoelastic problem. Green's function is given by the superposition of plane waves. Each plane wave is expressed in terms of matrix-valued attenuation and dispersion functions given in terms of a matrix-valued positive semi-definite Radon measure. More explicit formulae are obtained for 3D isotropic viscoelastic Green's functions. As an example of an anisotropic medium the transversely isotropic medium with a constant symmetry axis is considered.

  5. Octupole deformation in light actinides within an analytic quadrupole octupole axially symmetric model with Davidson potential

    E-Print Network [OSTI]

    Bonatsos, Dennis; Minkov, N; Karampagia, S; Petrellis, D

    2015-01-01T23:59:59.000Z

    The analytic quadrupole octupole axially symmetric model, which had successfully predicted 226Ra and 226Th as lying at the border between the regions of octupole deformation and octupole vibrations in the light actinides using an infinite well potential (AQOA-IW), is made applicable to a wider region of nuclei exhibiting octupole deformation, through the use of a Davidson potential (AQOA-D). Analytic expressions for energy spectra and B(E1), B(E2), B(E3) transition rates are derived. The spectra of 222-226Ra and 224,226Th are described in terms of the two parameters phi_0 (expressing the relative amount of octupole vs. quadrupole deformation) and beta_0 (the position of the minimum of the Davidson potential), while the recently determined B(EL) transition rates of 224Ra, presenting stable octupole deformation, are successfully reproduced. A procedure for gradually determining the parameters appearing in the B(EL) transitions from a minimum set of data, thus increasing the predictive power of the model, is out...

  6. Initial-Value and Modal Approaches for Transient Viscoelastic Responses

    E-Print Network [OSTI]

    Hanyk, Ladislav

    ) and Peltier (1974) because of the availability of more precise uplift data with more extensive geographical principle and use of the viscoelastic normal-mode approach (e.g., Peltier 1974; Yuen & Peltier 1982 in the presence of complicated stratified earth models (Han & Wahr 1995; Fang & Hager 1994, 1995; Peltier 1995

  7. InitialValue and Modal Approaches for Transient Viscoelastic Responses

    E-Print Network [OSTI]

    Hanyk, Ladislav

    ) and Peltier (1974) because of the availability of more precise uplift data with more extensive geographical principle and use of the viscoelastic normal­mode approach (e.g., Peltier 1974; Yuen & Peltier 1982 in the presence of complicated stratified earth models (Han & Wahr 1995; Fang & Hager 1994, 1995; Peltier 1995

  8. HERMES: A Model to Describe Deformation, Burning, Explosion, and Detonation

    SciTech Connect (OSTI)

    Reaugh, J E

    2011-11-22T23:59:59.000Z

    HERMES (High Explosive Response to MEchanical Stimulus) was developed to fill the need for a model to describe an explosive response of the type described as BVR (Burn to Violent Response) or HEVR (High Explosive Violent Response). Characteristically this response leaves a substantial amount of explosive unconsumed, the time to reaction is long, and the peak pressure developed is low. In contrast, detonations characteristically consume all explosive present, the time to reaction is short, and peak pressures are high. However, most of the previous models to describe explosive response were models for detonation. The earliest models to describe the response of explosives to mechanical stimulus in computer simulations were applied to intentional detonation (performance) of nearly ideal explosives. In this case, an ideal explosive is one with a vanishingly small reaction zone. A detonation is supersonic with respect to the undetonated explosive (reactant). The reactant cannot respond to the pressure of the detonation before the detonation front arrives, so the precise compressibility of the reactant does not matter. Further, the mesh sizes that were practical for the computer resources then available were large with respect to the reaction zone. As a result, methods then used to model detonations, known as {beta}-burn or program burn, were not intended to resolve the structure of the reaction zone. Instead, these methods spread the detonation front over a few finite-difference zones, in the same spirit that artificial viscosity is used to spread the shock front in inert materials over a few finite-difference zones. These methods are still widely used when the structure of the reaction zone and the build-up to detonation are unimportant. Later detonation models resolved the reaction zone. These models were applied both to performance, particularly as it is affected by the size of the charge, and to situations in which the stimulus was less than that needed for reliable performance, whether as a result of accident, hazard, or a fault in the detonation train. These models describe the build-up of detonation from a shock stimulus. They are generally consistent with the mesoscale picture of ignition at many small defects in the plane of the shock front and the growth of the resulting hot-spots, leading to detonation in heterogeneous explosives such as plastic-bonded explosives (PBX). The models included terms for ignition, and also for the growth of reaction as tracked by the local mass fraction of product gas, {lambda}. The growth of reaction in such models incorporates a form factor that describes the change of surface area per unit volume (specific surface area) as the reaction progresses. For unimolecular crystalline-based explosives, the form factor is consistent with the mesoscale picture of a galaxy of hot spots burning outward and eventually interacting with each other. For composite explosives and propellants, where the fuel and oxidizer are segregated, the diffusion flame at the fuel-oxidizer interface can be interpreted with a different form factor that corresponds to grains burning inward from their surfaces. The form factor influences the energy release rate, and the amount of energy released in the reaction zone. Since the 19th century, gun and cannon propellants have used perforated geometric shapes that produce an increasing surface area as the propellant burns. This helps maintain the pressure as burning continues while the projectile travels down the barrel, which thereby increases the volume of the hot gas. Interior ballistics calculations use a geometric form factor to describe the changing surface area precisely. As a result, with a suitably modified form factor, detonation models can represent burning and explosion in damaged and broken reactant. The disadvantage of such models in application to accidents is that the ignition term does not distinguish between a value of pressure that results from a shock, and the same pressure that results from a more gradual increase. This disagrees with experiments, where

  9. Using Active Deformable Models in Robotic Visual Servoing

    E-Print Network [OSTI]

    of Minnesota 4-192 EE/CS Building 200 Union Street SE Minneapolis, MN 55455 September 9, 1997 Submitted to the book \\Event-Based Sensing, Planning and Control of a Robotic System: An Integrated Approach" #12 are updated at frame rates by minimizing an energy function involving the relative position of model points

  10. THERMOMECHANICS OF PV MODULES INCLUDING THE VISCOELASTICITY OF EVA Ulrich Eitner1,

    E-Print Network [OSTI]

    ]. It is therefore essential to understand the thermomechanics, i.e. the build-up of stresses from thermal] at the Fraunhofer CSP to inspect copper ribbons in PV modules. In 2010, we presented a viscoelastic material model

  11. The strain path dependence of plastic deformation response of AA5754: Experiment and modeling

    SciTech Connect (OSTI)

    Pham, Minh-Son [Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA and NIST Center for Automotive Lightweighting, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899-8553 (United States); Hu, Lin [Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA and Now at IBM (United States); Iadicola, Mark; Creuziger, Adam [NIST Center for Automotive Lightweighting, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899-8553 (United States); Rollett, Anthony D. [Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States)

    2013-12-16T23:59:59.000Z

    This work presents modeling of experiments on a balanced biaxial (BB) pre-strained AA5754 alloy, subsequently reloaded uniaxially along the rolling direction and transverse direction. The material exhibits a complex plastic deformation response during the change in strain path due to 1) crystallographic texture, 2) aging (interactions between dislocations and Mg atoms) and 3) recovery (annihilation and re-arrangement of dislocations). With a BB prestrain of about 5 %, the aging process is dominant, and the yield strength for uniaxially deformed samples is observed to be higher than the flow stress during BB straining. The strain hardening rate after changing path is, however, lower than that for pre-straining. Higher degrees of pre-straining make the dynamic recovery more active. The dynamic recovery at higher strain levels compensates for the aging effect, and results in: 1) a reduction of the yield strength, and 2) an increase in the hardening rate of re-strained specimens along other directions. The yield strength of deformed samples is further reduced if these samples are left at room temperature to let static recovery occur. The synergistic influences of texture condition, aging and recovery processes on the material response make the modeling of strain path dependence of mechanical behavior of AA5754 challenging. In this study, the influence of crystallographic texture is taken into account by incorporating the latent hardening into a visco-plastic self-consistent model. Different strengths of dislocation glide interaction models in 24 slip systems are used to represent the latent hardening. Moreover, the aging and recovery effects are also included into the latent hardening model by considering strong interactions between dislocations and dissolved atom Mg and the microstructural evolution. These microstructural considerations provide a powerful capability to successfully describe the strain path dependence of plastic deformation behavior of AA5754.

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

    SciTech Connect (OSTI)

    Freed, Alan D.; Einstein, Daniel R.

    2011-04-14T23:59:59.000Z

    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.

  13. Deformed Matrix Models, Supersymmetric Lattice Twists and N=1/4 Supersymmetry

    SciTech Connect (OSTI)

    Unsal, Mithat

    2008-09-24T23:59:59.000Z

    A manifestly supersymmetric nonperturbative matrix regularization for a twisted version of N = (8, 8) theory on a curved background (a two-sphere) is constructed. Both continuum and the matrix regularization respect four exact scalar supersymmetries under a twisted version of the supersymmetry algebra. We then discuss a succinct Q = 1 deformed matrix model regularization of N = 4 SYM in d = 4, which is equivalent to a non-commutative A*{sub 4} orbifold lattice formulation. Motivated by recent progress in supersymmetric lattices, we also propose a N = 1/4 supersymmetry preserving deformation of N = 4 SYM theory on R{sup 4}. In this class of N = 1/4 theories, both the regularized and continuum theory respect the same set of (scalar) supersymmetry. By using the equivalence of the deformed matrix models with the lattice formulations, we give a very simple physical argument on why the exact lattice supersymmetry must be a subset of scalar subalgebra. This argument disagrees with the recent claims of the link approach, for which we give a new interpretation.

  14. Experimental characterization and crystal plasticity modeling of heterogeneous deformation in polycrystalline -Ti

    SciTech Connect (OSTI)

    Wang, Leyun [Michigan State University, East Lansing; Barabash, Rozaliya [ORNL; Yang, Y [Michigan State University, East Lansing; Bieler, Prof T R [Michigan State University, East Lansing; Crimp, Prof M A [Michigan State University, East Lansing; Eisenlohr, P [Max-Planck-Institut fur Eisenforschung, Germany; Liu, W. [Argonne National Laboratory (ANL); Ice, Gene E [ORNL

    2011-01-01T23:59:59.000Z

    Grain-level heterogeneous deformation was studied in a polycrystalline {alpha}-Ti specimen deformed by four-point bending. Dislocation slip activity in the microstructure was investigated by surface slip trace analysis. Three-dimensional-X-ray diffraction (3D-XRD) was used to investigate subsurface lattice rotations and to identify geometrically necessary dislocations (GNDs). The slip systems of local GNDs were analyzed by studying the streaking directions of reflections in corresponding Laue patterns. The analysis performed in one grain indicated that the subsurface GNDs were from the same slip system identified using slip trace analysis in backscattered electron images. A crystal plasticity finite element (CPFE) model was used to simulate deformation of the same microstructural region. The predictions of dislocation slip activity match the general aspects of the experimental observations, including the ability to simulate the activation of different slip systems in grains where multiple slip systems were activated. Prediction of local crystal rotations, however, was the least accurate aspect of the CPFE model.

  15. Modelling the viscoplastic behavior and the heterogeneous intracrystalline deformation of columnar ice polycrystals

    SciTech Connect (OSTI)

    Lebensohn, Ricardo A [Los Alamos National Laboratory; Montagnat, Maurine [LGGE (FRANCE); Mansuy, Philippe [MICHELIN (FRANCE); Duval, Paul [LGGE (FRANCE); Philip, A [LGGE (FRANCE)

    2008-01-01T23:59:59.000Z

    A full-field formulation based on Fast Fourier Transforms (FFT) has been adapted and used to predict the micromechanical fields that develop in columnar Ih ice polycrystals deforming in compression by dislocation creep. The predicted intragranular mechanical fields are in qualitative good agreement with experimental observations, in particular those involving the formation of shear and kink bands. These localization bands are associated with the large internal stresses that develop during creep in such anisotropic material, and their location, intensity, morphology and extension are found to depend strongly on the crystallographic orientation of the grains and on their interaction with neighbor crystals. The predictions of the model are also discussed in relation with the deformation of columnar sea and lake ice, and with the mechanical behavior of granular ice of glaciers and polar ice sheets, as well.

  16. axially accelerating viscoelastic: Topics by E-print Network

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

    part Paris-Sud XI, Universit de 385 VISCOELASTIC BEHAVIOR OF POLYMER-THICKENED WATER-IN-OIL EMULSIONS Materials Science Websites Summary: VISCOELASTIC BEHAVIOR OF...

  17. Non-Steady wall-bounded flows of viscoelastic fluids under periodic forcing

    E-Print Network [OSTI]

    Anier Hernández-García; Antonio Fernández-Barbero; Oscar Sotolongo-Costa

    2013-01-18T23:59:59.000Z

    The problem of oscillating flows inside pipes under periodic forcing of viscoelastic fluids is addressed here. Starting from the linear Oldroyd-B model, a generalized Darcy's law is obtained in frequency domain and an explicit expression for the dependence of the dynamic permeability on fluid parameters and forcing frequency is derived. Previous results in both viscoelastic and Newtonian fluids are here shown to be particular cases of our results. On the basis of our calculations, a possible explanation for the observed damping of local dynamic response as the forcing frequency increases is given. Good fitting with recent experimental studies of wave propagation in viscoelastic media is here exhibited. Sound wave propagation in viscoelastic media flowing inside straight pipes is investigated. In particular, we obtain the local dynamic response for weakly compressible flows.

  18. Multi-scale Modeling Approach to Acoustic Emission during Plastic Deformation

    E-Print Network [OSTI]

    Jagadish Kumar; G. Ananthakrishna

    2011-02-20T23:59:59.000Z

    We address the long standing problem of the origin of acoustic emission commonly observed during plastic deformation. We propose a frame-work to deal with the widely separated time scales of collective dislocation dynamics and elastic degrees of freedom to explain the nature of acoustic emission observed during the Portevin-Le Chatelier effect. The Ananthakrishna model is used as it explains most generic features of the phenomenon. Our results show that while acoustic emission bursts correlated with stress drops are well separated for the type C serrations, these bursts merge to form nearly continuous acoustic signals with overriding bursts for the propagating type A bands.

  19. A Simple Model for the Deformation-Induced Relaxation of Glassy Polymers

    E-Print Network [OSTI]

    S. M. Fielding; R. G. Larson; M. E. Cates

    2011-10-18T23:59:59.000Z

    Glassy polymers show strain hardening: at constant extensional load, their flow first accelerates, then arrests. Recent experiments have found this to be accompanied by a striking and unexplained dip in the segmental relaxation time. Here we explain such behavior by combining a minimal model of flow-induced liquefaction of a glass, with a description of the stress carried by strained polymers, creating a non-factorable interplay between aging and strain-induced rejuvenation. Under constant load, liquefaction of segmental motion permits strong flow that creates polymer-borne stress. This slows the deformation enough for the segmental modes to re-vitrify, causing strain hardening.

  20. A voxel-based finite element model for the prediction of bladder deformation

    SciTech Connect (OSTI)

    Chai Xiangfei; Herk, Marcel van; Hulshof, Maarten C. C. M.; Bel, Arjan [Radiation Oncology Department, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam (Netherlands); Radiation Oncology Department, Netherlands Cancer Institute, 1066 CX Amsterdam (Netherlands); Radiation Oncology Department, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam (Netherlands)

    2012-01-15T23:59:59.000Z

    Purpose: A finite element (FE) bladder model was previously developed to predict bladder deformation caused by bladder filling change. However, two factors prevent a wide application of FE models: (1) the labor required to construct a FE model with high quality mesh and (2) long computation time needed to construct the FE model and solve the FE equations. In this work, we address these issues by constructing a low-resolution voxel-based FE bladder model directly from the binary segmentation images and compare the accuracy and computational efficiency of the voxel-based model used to simulate bladder deformation with those of a classical FE model with a tetrahedral mesh. Methods: For ten healthy volunteers, a series of MRI scans of the pelvic region was recorded at regular intervals of 10 min over 1 h. For this series of scans, the bladder volume gradually increased while rectal volume remained constant. All pelvic structures were defined from a reference image for each volunteer, including bladder wall, small bowel, prostate (male), uterus (female), rectum, pelvic bone, spine, and the rest of the body. Four separate FE models were constructed from these structures: one with a tetrahedral mesh (used in previous study), one with a uniform hexahedral mesh, one with a nonuniform hexahedral mesh, and one with a low-resolution nonuniform hexahedral mesh. Appropriate material properties were assigned to all structures and uniform pressure was applied to the inner bladder wall to simulate bladder deformation from urine inflow. Performance of the hexahedral meshes was evaluated against the performance of the standard tetrahedral mesh by comparing the accuracy of bladder shape prediction and computational efficiency. Results: FE model with a hexahedral mesh can be quickly and automatically constructed. No substantial differences were observed between the simulation results of the tetrahedral mesh and hexahedral meshes (<1% difference in mean dice similarity coefficient to manual contours and <0.02 cm difference in mean standard deviation of residual errors). The average equation solving time (without manual intervention) for the first two types of hexahedral meshes increased to 2.3 h and 2.6 h compared to the 1.1 h needed for the tetrahedral mesh, however, the low-resolution nonuniform hexahedral mesh dramatically decreased the equation solving time to 3 min without reducing accuracy. Conclusions: Voxel-based mesh generation allows fast, automatic, and robust creation of finite element bladder models directly from binary segmentation images without user intervention. Even the low-resolution voxel-based hexahedral mesh yields comparable accuracy in bladder shape prediction and more than 20 times faster in computational speed compared to the tetrahedral mesh. This approach makes it more feasible and accessible to apply FE method to model bladder deformation in adaptive radiotherapy.

  1. Testing some models of foreland deformation at the Thermopolis anticline, southern Bighorn Basin, Wyoming

    SciTech Connect (OSTI)

    Paylor, E.D.; Lang, H.R.; Conel, J.E.; Adams, S.L. (California Institute of Technology, Pasadena (USA)); Muncy, H.L. (Tenneco Oil Exploration and Production, Englewood, CO (USA))

    1989-01-01T23:59:59.000Z

    The Thermopolis anticline is a typical structure in the Rocky Mountain foreland, southern Bighorn Basin, Wyoming. Photogeologic interpretation of Landsat Thematic Mapper data, in combination with the evaluation of topographic, bore hole, seismic reflection, and field data were used to analyze structure and constrain tectonic models. The anticline is near-concentric, asymmetric with a southwest sense of vergence, and plunges to the northwest. The steeply dipping to overturned southwest limb of the fold is cut at the surface by several thrust faults dipping northeast. Approximately 25% of the stratigraphic section on the southwest limb is missing due to faulting. Two east to northeast-striking, basement-controlled compartmental faults segment the anticline into three blocks that apparently deformed simultaneously but probably independently from one another. Slickensides indicate a dominant southwest tectonic transport direction. Additionally, subtle northeast-trending folds are superposed on the dominant northwest structural trend. Structural patterns at Thermopolis anticline can be explained using models that propose a single phase of northeast Laramide compression, combined with shear-zone deformation.

  2. Finite Element Modeling of the Deformation of a Thin Magnetoelastic Film Compared to a Membrane Model

    SciTech Connect (OSTI)

    Barham, M; White, D; Steigmann, D; Rudd, R

    2009-04-08T23:59:59.000Z

    Recently a new class of biocompatible elastic polymers loaded with small ferrous particles (magnetoelastomer) was developed at Lawrence Livermore National Laboratory. This new material was formed as a thin film using spin casting. The deformation of this material using a magnetic field has many possible applications to microfluidics. Two methods will be used to calculate the deformation of a circular magneto-elastomeric film subjected to a magnetic field. The first method is an arbitrary Lagrangian-Eulerian (ALE) finite element method (FEM) and the second is based on nonlinear continuum electromagnetism and continuum elasticity in the membrane limit. The comparison of these two methods is used to test/validate the finite element method.

  3. Modeling reactive transport in deformable porous media using the theory of interacting continua.

    SciTech Connect (OSTI)

    Turner, Daniel Zack

    2012-01-01T23:59:59.000Z

    This report gives an overview of the work done as part of an Early Career LDRD aimed at modeling flow induced damage of materials involving chemical reactions, deformation of the porous matrix, and complex flow phenomena. The numerical formulation is motivated by a mixture theory or theory of interacting continua type approach to coupling the behavior of the fluid and the porous matrix. Results for the proposed method are presented for several engineering problems of interest including carbon dioxide sequestration, hydraulic fracturing, and energetic materials applications. This work is intended to create a general framework for flow induced damage that can be further developed in each of the particular areas addressed below. The results show both convincing proof of the methodologies potential and the need for further validation of the models developed.

  4. A phase-field model for systems with coupled large deformation and mass Wei Hong1,2

    E-Print Network [OSTI]

    Hong, Wei

    1 A phase-field model for systems with coupled large deformation and mass transport Wei Hong1 to introduce phase-field modeling to the field of soft materials, especially for studying polymeric gels-field methodology, and reveal some interesting phenomena due to the coupling. For example, the composition

  5. Viscoelastic properties of bidisperse homopolymer blends

    E-Print Network [OSTI]

    Juliani

    2000-01-01T23:59:59.000Z

    VISCOELASTIC PROPERTIES OF BIDISPKRSE HOMOPOLYMER BLENDS A Thesis by JULIANI 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 2000... Major Subject. Chemical Engineering VISCOELASTIC PROPERTIES OF BIDISPERSE HOMOPOLYMER BLENDS A Thesis by JULIANI Submitted to Texas A&M University m partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to style...

  6. Nonlinear Shear Wave in a Non Newtonian Visco-elastic Medium

    E-Print Network [OSTI]

    Janaki, D Banerjee M S; Chaudhuri, M

    2013-01-01T23:59:59.000Z

    An analysis of nonlinear transverse shear wave has been carried out on non-Newtonian viscoelastic liquid using generalized hydrodynamic(GH) model. The nonlinear viscoelastic behavior is introduced through velocity shear dependence of viscosity coefficient by well known Carreau -Bird model. The dynamical feature of this shear wave leads to the celebrated Fermi-Pasta-Ulam (FPU) problem. Numerical solution has been obtained which shows that initial periodic solutions reoccur after passing through several patterns of periodic waves. A possible explanation for this periodic solution is given by constructing modified Korteweg de Vries (mKdV) equation. This model has application from laboratory to astrophysical plasmas as well as biological systems.

  7. On the intersection of the shell, collective and cluster models of atomic nuclei II: Symmetry-breaking and large deformations

    E-Print Network [OSTI]

    J. Cseh; J. Darai

    2014-04-14T23:59:59.000Z

    We discuss the role of the broken symmetries in the connection of the shell, collective and cluster models. The cluster-shell competition is described in terms of cold quantum phases. Stable quasi-dynamical U(3) symmetry is found for specific large deformations for a Nilsson-type Hamiltonian.

  8. Multiscale modeling of ice deformation behavior M. Montagnata,, O. Castelnaub, P. D. Bonsc, S. H. Fariad,e, O.

    E-Print Network [OSTI]

    Boyer, Edmond

    Multiscale modeling of ice deformation behavior M. Montagnata,, O. Castelnaub, P. D. Bonsc, S. H France (IUF), Paris, France Abstract Understanding the flow of ice in glaciers and polar ice sheets is of increasing relevance in a time of potentially significant climate change. The flow of ice has hitherto

  9. 3D segmentation of mouse organs from MR images using deformable simplex mesh models G. Hamarneh1

    E-Print Network [OSTI]

    Hamarneh, Ghassan

    3D segmentation of mouse organs from MR images using deformable simplex mesh models G. Hamarneh1 , H. Delingette2 , M. Henkelman1 1 Hospital for Sick Children, Toronto, ON, Canada, 2 INRIA brains and kidneys from MR images. Algorithmic details and 3D segmentation results are presented

  10. Squeeze flow of potato starch gel: effect of loading history on visco-elastic properties

    E-Print Network [OSTI]

    Moutushi Dutta Choudhury; Shantanu Das; Sujata Tarafdar

    2015-03-25T23:59:59.000Z

    In this work gelatinized potato starch is shown to retain the memory of past loading history. It exhibits a visco-elastic response which does not depend solely on instantaneous conditions. A simple squeeze flow experiment is performed, where loading is done in two steps with a time lag $\\tau \\sim$ seconds between the steps. The effect on the strain, of varying $\\tau$ is reproduced by a three element visco-elastic solid model. Non-linearity is introduced through a generalized calculus approach by incorporating a non-integer order time derivative in the viscosity equation. A strain hardening proportional to the time lag between the two loading steps is also incorporated. This model reproduces the three salient features observed in the experiment, namely - the memory effect, slight initial oscillations in the strain as well as the long-time solid-like response. Dynamic visco-elasticity of the sample is also reported.

  11. Fluid substitution in rocks saturated with viscoelastic fluids Dina Makarynska1

    E-Print Network [OSTI]

    , Jyoti Behura3 , and Mike Batzle4 ABSTRACT Heavy oils have high densities and extremely high viscosities sands.We model the viscoelastic properties of a heavy- oil-saturated rock sample using CPA and a measured frequency- dependent complex shear modulus of the heavy oil. Comparison of modeled results

  12. Viscoelastic DampingViscoelastic Damping Characteristics of Indium-Tin/Characteristics of Indium-Tin/SiCSiC

    E-Print Network [OSTI]

    Swan Jr., Colby Corson

    1 Viscoelastic DampingViscoelastic Damping Characteristics of Indium-Tin/Characteristics of Indium-Tin Approach: · Based on past experience, indium-tin has well- characterized stiffness/damping. · Fabricate

  13. Surface Loading of a Multilayered Viscoelastic Pavement: Semianalytical Solution

    E-Print Network [OSTI]

    Pan, Ernie

    Surface Loading of a Multilayered Viscoelastic Pavement: Semianalytical Solution Ewan Y. G. Chen1 response of a linear viscoelastic pavement. The material parameters of the asphalt concrete analytically. Therefore, responses of the viscoelastic pavement are finally expressed analytically in the time

  14. A dislocation-based, strain–gradient–plasticity strengthening model for deformation processed metal–metal composites

    SciTech Connect (OSTI)

    Tian, Liang [Ames Laboratory; Russell, Alan [Ames Laboratory; Anderson, Iver [Ames Laboratory

    2014-01-03T23:59:59.000Z

    Deformation processed metal–metal composites (DMMCs) are high-strength, high-electrical conductivity composites developed by severe plastic deformation of two ductile metal phases. The extraordinarily high strength of DMMCs is underestimated using the rule of mixture (or volumetric weighted average) of conventionally work-hardened metals. In this article, a dislocation-density-based, strain–gradient–plasticity model is proposed to relate the strain-gradient effect with the geometrically necessary dislocations emanating from the interface to better predict the strength of DMMCs. The model prediction was compared with the experimental findings of Cu–Nb, Cu–Ta, and Al–Ti DMMC systems to verify the applicability of the new model. The results show that this model predicts the strength of DMMCs better than the rule-of-mixture model. The strain-gradient effect, responsible for the exceptionally high strength of heavily cold worked DMMCs, is dominant at large deformation strain since its characteristic microstructure length is comparable with the intrinsic material length.

  15. Adaptive Hierarchical Multiscale Framework for Modeling the Deformation of Ultra-Strong Nano-structured Materials

    E-Print Network [OSTI]

    Ghoniem, Nasr M.

    , we plan to investigate the deformation characteris- tics of two classes of nano-structured materials. The proposed research will also impact graduate education world-wide by the developme

  16. Solving the two-center nuclear shell-model problem with arbitrarily-orientated deformed potentials

    E-Print Network [OSTI]

    Alexis Diaz-Torres

    2008-10-02T23:59:59.000Z

    A general new technique to solve the two-center problem with arbitrarily-orientated deformed realistic potentials is demonstrated, which is based on the powerful potential separable expansion method. As an example, molecular single-particle spectra for $^{12}$C + $^{12}$C $\\to$ $^{24}$Mg are calculated using deformed Woods-Saxon potentials. These clearly show that non-axial symmetric configurations play a crucial role in molecular resonances observed in reaction processes for this system at low energy.

  17. Propulsion in a viscoelastic fluid Eric Laugaa

    E-Print Network [OSTI]

    Lauga, Eric

    and a healthy respiratory system.8 Cilia are short flagella which produce fluid motion by means mechanisms and propulsion.9 In the upper respiratory tract, cilia are located in a thin layer of low influenced by viscoelastic stresses. Relevant examples include the ciliary transport of respiratory airway

  18. Using Nanotechnology in Viscoelastic Surfactant Stimulation Fluids 

    E-Print Network [OSTI]

    Gurluk, Merve Rabia 1986-

    2012-11-12T23:59:59.000Z

    USING NANOTECHNOLOGY IN VISCOELASTIC SURFACTANT STIMULATION FLUIDS A Thesis by MERVE RABIA GURLUK Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... .......................................... 9 1.7 Kinetics of Micellization ......................................................................... 10 1.8 Nanotechnology ....................................................................................... 16...

  19. Nuclear-deformation energies according to a liquid-drop model with a sharp surface

    SciTech Connect (OSTI)

    Blocki, J.; Swiatecki, W.J.

    1982-05-01T23:59:59.000Z

    We present an atlas of 665 deformation-energy maps and 150 maps of other properties of interest, relevant for nuclear systems idealized as uniformly charged drops endowed with a surface tension. The nuclear shapes are parametrized in terms of two spheres modified by a smoothly fitted quadratic surface of revolution and are specified by three variables: asymmetry, sphere separation, and a neck variable (that goes over into a fragment-deformation variable after scission). The maps and related tables should be useful for the study of macroscopic aspects of nuclear fission and of collisions between any two nuclei in the periodic table.

  20. Spacetimes for ?-deformations

    E-Print Network [OSTI]

    Konstantinos Sfetsos; Daniel C. Thompson

    2014-10-07T23:59:59.000Z

    We examine a recently proposed class of integrable deformations to two-dimensional conformal field theories. These {\\lambda}-deformations interpolate between a WZW model and the non-Abelian T-dual of a Principal Chiral Model on a group G or, between a G/H gauged WZW model and the non-Abelian T-dual of the geometric coset G/H. {\\lambda}-deformations have been conjectured to represent quantum group q-deformations for the case where the deformation parameter is a root of unity. In this work we show how such deformations can be given an embedding as full string backgrounds whose target spaces satisfy the equations of type-II supergravity. One illustrative example is a deformation of the Sl(2,R)/U(1) black-hole CFT. A further example interpolates between the $\\frac{SU(2)\\times SU(2)}{SU(2)}\\times\\frac{SL(2,R)\\times SL(2,R)}{SL(2,R)} \\times U(1)^4$ gauged WZW model and the non-Abelian T-dual of $AdS_3\\times S^3\\times T^4$ supported with Ramond flux.

  1. Existence and Regularity for Dynamic Viscoelastic Adhesive Contact with Damage

    SciTech Connect (OSTI)

    Kuttler, Kenneth L. [Department of Mathematics, Brigham Young University, Provo, UT 84602 (United States)], E-mail: klkuttler@math.byu.edu; Shillor, Meir [Department of Mathematics and Statistics, Oakland University, Rochester, MI 48309 (United States)], E-mail: shillor@oakland.edu; Fernandez, Jose R. [Departamento de Matematica Aplicada, Facultade de Matematicas, University of Santiago de Compostela, 15706 Santiago de Compostela (Spain)], E-mail: jramon@usc.es

    2006-01-15T23:59:59.000Z

    A model for the dynamic process of frictionless adhesive contact between a viscoelastic body and a reactive foundation, which takes into account the damage of the material resulting from tension or compression, is presented. Contact is described by the normal compliance condition. Material damage is modelled by the damage field, which measures the pointwise fractional decrease in the load-carrying capacity of the material, and its evolution is described by a differential inclusion. The model allows for different damage rates caused by tension or compression. The adhesion is modelled by the bonding field, which measures the fraction of active bonds on the contact surface. The existence of the unique weak solution is established using the theory of set-valued pseudomonotone operators introduced by Kuttler and Shillor (1999). Additional regularity of the solution is obtained when the problem data is more regular and satisfies appropriate compatibility conditions.

  2. Analytical Study on Adhesively Bonded Joints Using Peeling Test and Symmetric Composite Models Based on Bernoulli-Euler and Timoshenko Beam Theories for Elastic and Viscoelastic Materials

    E-Print Network [OSTI]

    Su, Ying-Yu

    2012-02-14T23:59:59.000Z

    Adhesively bonded joints have been investigated for several decades. In most analytical studies, the Bernoulli-Euler beam theory is employed to describe the behaviour of adherends. In the current work, three analytical models are developed...

  3. Analytical and experimental procedures in nonlinear viscoelastic parameter characterization using dynamic mechanical techniques 

    E-Print Network [OSTI]

    Golden, Peter Joseph

    1996-01-01T23:59:59.000Z

    Traditional methods of viscoelastic material characterization lack the ability to rapidly characterize nonlinear viscoelastic materials. A method of rapidly identifying linear viscoelastic material properties is Dynamic Mechanical Analysis (DMA...

  4. Triaxially deformed relativistic point-coupling model for $?$ hypernuclei: a quantitative analysis of hyperon impurity effect on nuclear collective properties

    E-Print Network [OSTI]

    W. X. Xue; J. M. Yao; K. Hagino; Z. P. Li; H. Mei; Y. Tanimura

    2015-02-18T23:59:59.000Z

    The impurity effect of hyperon on atomic nuclei has received a renewed interest in nuclear physics since the first experimental observation of appreciable reduction of $E2$ transition strength in low-lying states of hypernucleus $^{7}_\\Lambda$Li. Many more data on low-lying states of $\\Lambda$ hypernuclei will be measured soon for $sd$-shell nuclei, providing good opportunities to study the $\\Lambda$ impurity effect on nuclear low-energy excitations. We carry out a quantitative analysis of $\\Lambda$ hyperon impurity effect on the low-lying states of $sd$-shell nuclei at the beyond-mean-field level based on a relativistic point-coupling energy density functional (EDF), considering that the $\\Lambda$ hyperon is injected into the lowest positive-parity ($\\Lambda_s$) and negative-parity ($\\Lambda_p$) states. We adopt a triaxially deformed relativistic mean-field (RMF) approach for hypernuclei and calculate the $\\Lambda$ binding energies of hypernuclei as well as the potential energy surfaces (PESs) in $(\\beta, \\gamma)$ deformation plane. We also calculate the PESs for the $\\Lambda$ hypernuclei with good quantum numbers using a microscopic particle rotor model (PRM) with the same relativistic EDF. The triaxially deformed RMF approach is further applied in order to determine the parameters of a five-dimensional collective Hamiltonian (5DCH) for the collective excitations of triaxially deformed core nuclei. Taking $^{25,27}_{\\Lambda}$Mg and $^{31}_{\\Lambda}$Si as examples, we analyse the impurity effects of $\\Lambda_s$ and $\\Lambda_p$ on the low-lying states of the core nuclei...

  5. Constitutive modelling of shape memory alloys and upscaling of deformable porous media 

    E-Print Network [OSTI]

    Popov, Petar Angelov

    2005-08-29T23:59:59.000Z

    phases is also possible. The critical temperatures are denoted on the temperature axis. In addition, the critical uniaxial stresses for beginning sigmas and finish sigmaf of the detwinning deformation are shown on the stress axis. The shape memory effects.... For example, in copper-based alloys, twenty-four variants of martensite constitute six self-accommodated groups scattered around the angbracketleft011angbracketright poles of austenite with a typical diamond morphology. The growth of such groups 9 Fig. 2...

  6. Deformation of layered rocks in the ramp regions of thrust faults: a study with rock models

    E-Print Network [OSTI]

    Chester, Judith Savaso

    1985-01-01T23:59:59.000Z

    and thrust belts for example, thrust faults commonly occur along specific stratigraphic horizons, and folding and faulting within thrust sheets often involves slip along bedding planes (e. g. , Rich, 1934; Douglas, 1950; Dahl str om, 1970; Price, 1981...). With the regional framework of many fold and thrust belts well estab- lished, the current emphasis of many studies has turned to defining the geometries, kinematics, and deformation mechanisms of individual thrust belt structures, and the intrinsic and extrinsic...

  7. Thermo-responsive viscoelastic wormlike micelle to elastic hydrogel transition in dual-component systems

    E-Print Network [OSTI]

    Huang, Jianbin

    Thermo-responsive viscoelastic wormlike micelle to elastic hydrogel transition in dual report a thermo-responsive phase transition from a viscoelastic wormlike micelle solution to an elastic

  8. Nonlinear viscoelastic materials : bioinspired applications and new characterization measures

    E-Print Network [OSTI]

    Ewoldt, Randy H. (Randy Harold)

    2009-01-01T23:59:59.000Z

    Viscoelastic materials, such as biomaterials and non-Newtonian fluids, typically experience mechanical loading which evokes a nonlinear rheological response. Rheologically complex materials can provide novel functionality ...

  9. On the Rheology of Cold Drawing. 11. Viscoelastic Materials*

    E-Print Network [OSTI]

    On the Rheology of Cold Drawing. 11. Viscoelastic Materials* BERNARD D. COLEMAN and DANIEL C. NEWMAN Department of Mechanics and Materials Science, Rutgers, The State University of New Jersey viscoelastic materials subject to inhomogeneous stretching. The formulae, which are valid to within an error

  10. Implementation and Evaluation of the Virtual Fields Method: Determining Constitutive Model Parameters From Full-Field Deformation Data.

    SciTech Connect (OSTI)

    Kramer, Sharlotte Lorraine Bolyard; Scherzinger, William M.

    2014-09-01T23:59:59.000Z

    The Virtual Fields Method (VFM) is an inverse method for constitutive model parameter identication that relies on full-eld experimental measurements of displacements. VFM is an alternative to standard approaches that require several experiments of simple geometries to calibrate a constitutive model. VFM is one of several techniques that use full-eld exper- imental data, including Finite Element Method Updating (FEMU) techniques, but VFM is computationally fast, not requiring iterative FEM analyses. This report describes the im- plementation and evaluation of VFM primarily for nite-deformation plasticity constitutive models. VFM was successfully implemented in MATLAB and evaluated using simulated FEM data that included representative experimental noise found in the Digital Image Cor- relation (DIC) optical technique that provides full-eld displacement measurements. VFM was able to identify constitutive model parameters for the BCJ plasticity model even in the presence of simulated DIC noise, demonstrating VFM as a viable alternative inverse method. Further research is required before VFM can be adopted as a standard method for constitu- tive model parameter identication, but this study is a foundation for ongoing research at Sandia for improving constitutive model calibration.

  11. Rheology of human blood plasma: Viscoelastic versus Newtonian behavior

    E-Print Network [OSTI]

    M. Brust; C. Schaefer; L. Pan; M. Garcia; P. E. Arratia; C Wagner

    2013-02-17T23:59:59.000Z

    We investigate the rheological characteristics of human blood plasma in shear and elongational flows. While we can confirm a Newtonian behavior in shear flow within experimental resolution, we find a viscoelastic behavior of blood plasma in the pure extensional flow of a capillary break-up rheometer. The influence of the viscoelasticity of blood plasma on capillary blood flow is tested in a microfluidic device with a contraction-expansion geometry. Differential pressure measurements revealed that the plasma has a pronounced flow resistance compared to that of pure water. Supplementary measurements indicate that the viscoelasticity of the plasma might even lead to viscoelastic instabilities under certain conditions. Our findings show that the viscoelastic properties of plasma should not be ignored in future studies on blood flow.

  12. Modeling the thermal deformation of TATB-based explosives. Part 1: Thermal expansion of “neat-pressed” polycrystalline TATB

    SciTech Connect (OSTI)

    Luscher, Darby J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-05-08T23:59:59.000Z

    We detail a modeling approach to simulate the anisotropic thermal expansion of polycrystalline (1,3,5-triamino-2,4,6-trinitrobenzene) TATB-based explosives that utilizes microstructural information including porosity, crystal aspect ratio, and processing-induced texture. This report, the first in a series, focuses on nonlinear thermal expansion of “neat-pressed” polycrystalline TATB specimens which do not contain any binder; additional complexities related to polymeric binder and irreversible ratcheting behavior are briefly discussed, however detailed investigation of these aspects are deferred to subsequent reports. In this work we have, for the first time, developed a mesoscale continuum model relating the thermal expansion of polycrystal TATB specimens to their microstructural characteristics. A self-consistent homogenization procedure is used to relate macroscopic thermoelastic response to the constitutive behavior of single-crystal TATB. The model includes a representation of grain aspect ratio, porosity, and crystallographic texture attributed to the consolidation process. A quantitative model is proposed to describe the evolution of preferred orientation of graphitic planes in TATB during consolidation and an algorithm constructed to develop a discrete representation of the associated orientation distribution function. Analytical and numerical solutions using this model are shown to produce textures consistent with previous measurements and characterization for isostatic and uniaxial “die-pressed” specimens. Predicted thermal strain versus temperature for textured specimens are shown to be in agreement with corresponding experimental measurements. Using the developed modeling approach, several simulations have been run to investigate the influence of microstructure on macroscopic thermal expansion behavior. Results from these simulations are used to identify qualitative trends. Implications of the identified trends are discussed in the context of thermal deformation of engineered components whose consolidation process is generally more complex than isostatic or die-pressed specimens. Finally, an envisioned application of the modeling approach to simulating thermal expansion of weapon systems and components is outlined along with necessary future work to introduce the effects of binder and ratcheting behavior. Key conclusions from this work include the following. Both porosity and grain aspect ratio have an influence on the thermal expansion of polycrystal TATB considering realistic material variability. Thepreferred orientation of the single crystal TATB [001] poles within a polycrystal gives rise to pronounced anisotropy of the macroscopic thermal expansion. The extent of this preferred orientation depends on the magnitude of deformation, and consequently, is expected to vary spatially throughout manufactured components much like porosity. The modeling approach presented here has utility toward bringing spatially variable microstructural features into macroscale system engineering modelsAbstract Not Provided

  13. Modeling of coulpled deformation and permeability evolution during fault reactivation induced by deep underground injection of CO2

    SciTech Connect (OSTI)

    Cappa, F.; Rutqvist, J.

    2010-06-01T23:59:59.000Z

    The interaction between mechanical deformation and fluid flow in fault zones gives rise to a host of coupled hydromechanical processes fundamental to fault instability, induced seismicity, and associated fluid migration. In this paper, we discuss these coupled processes in general and describe three modeling approaches that have been considered to analyze fluid flow and stress coupling in fault-instability processes. First, fault hydromechanical models were tested to investigate fault behavior using different mechanical modeling approaches, including slip interface and finite-thickness elements with isotropic or anisotropic elasto-plastic constitutive models. The results of this investigation showed that fault hydromechanical behavior can be appropriately represented with the least complex alternative, using a finite-thickness element and isotropic plasticity. We utilized this pragmatic approach coupled with a strain-permeability model to study hydromechanical effects on fault instability during deep underground injection of CO{sub 2}. We demonstrated how such a modeling approach can be applied to determine the likelihood of fault reactivation and to estimate the associated loss of CO{sub 2} from the injection zone. It is shown that shear-enhanced permeability initiated where the fault intersects the injection zone plays an important role in propagating fault instability and permeability enhancement through the overlying caprock.

  14. Deformation processing of HTS wire

    SciTech Connect (OSTI)

    Bingert, J. [Los Alamos National Lab., NM (United States)

    1994-07-29T23:59:59.000Z

    Methods to understand, control, and optimize deformation processing of HTS wire are outlined. Topics discussed include: technical progress, deformation processing effects on HTS - core uniformity in composite tapes, effects of rolling on tapes, deformation process modeling, channel die powder compaction stress-strain data, microhardness versus rolling reduction, minimum bifurcation strain versus material state, roll gap geometries for large versus small rolls, interactions, hydrostatic extrusion, and tensile properties.

  15. Analysis of Crystal Lattice Deformation by Ion Channeling. |...

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

    Crystal Lattice Deformation by Ion Channeling. Analysis of Crystal Lattice Deformation by Ion Channeling. Abstract: A model of dislocations has been developed for the use in Monte...

  16. Kinematic models of deformation in Southern California constrained by geologic and geodetic data

    E-Print Network [OSTI]

    Eich, Lori A

    2006-01-01T23:59:59.000Z

    Using a standardized fault geometry based on the Community Block Model, we create two analytic block models of the southern California fault system. We constrain one model with only geodetic data. In the other, we assign ...

  17. (p,q)-Deformations and (p,q)-Vector Coherent States of the Jaynes-Cummings Model in the Rotating Wave Approximation

    E-Print Network [OSTI]

    Joseph Ben Geloun; Jan Govaerts; M. Norbert Hounkonnou

    2006-10-23T23:59:59.000Z

    Classes of (p,q)-deformations of the Jaynes-Cummings model in the rotating wave approximation are considered. Diagonalization of the Hamiltonian is performed exactly, leading to useful spectral decompositions of a series of relevant operators. The latter include ladder operators acting between adjacent energy eigenstates within two separate infinite discrete towers, except for a singleton state. These ladder operators allow for the construction of (p,q)-deformed vector coherent states. Using (p,q)-arithmetics, explicit and exact solutions to the associated moment problem are displayed, providing new classes of coherent states for such models. Finally, in the limit of decoupled spin sectors, our analysis translates into (p,q)-deformations of the supersymmetric harmonic oscillator, such that the two supersymmetric sectors get intertwined through the action of the ladder operators as well as in the associated coherent states.

  18. Towards the modeling of mucus draining from human lung: role of airways deformation on air-mucus interaction

    E-Print Network [OSTI]

    Mauroy, Benjamin; Pelca, Dominique; Fausser, Christian; Merckx, Jacques; Mitchell, Barrett R

    2015-01-01T23:59:59.000Z

    Chest physiotherapy is an empirical technique used to help secretions to get out of the lung whenever stagnation occurs. Although commonly used, little is known about the inner mechanisms of chest physiotherapy and controversies about its use are coming out regularly. Thus, a scientific validation of chest physiotherapy is needed to evaluate its effects on secretions. We setup a quasi-static numerical model of chest physiotherapy based on thorax and lung physiology and on their respective biophysics. We modeled the lung with an idealized deformable symmetric bifurcating tree. Bronchi and their inner fluids mechanics are assumed axisymmetric. Static data from the literature is used to build a model for the lung's mechanics. Secretions motion is the consequence of the shear constraints apply by the air flow. The input of the model is the pressure on the chest wall at each time, and the output is the bronchi geometry and air and secretions properties. In the limit of our model, we mimicked manual and mechanical ...

  19. Deformed shell model results for neutrinoless double beta decay of nuclei in A=60-90 region

    E-Print Network [OSTI]

    R. Sahu; V. K. B. Kota

    2015-03-20T23:59:59.000Z

    Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay of $^{70}$Zn, $^{80}$Se and $^{82}$Se nuclei are calculated within the framework of the deformed shell model based on Hartree-Fock states. For $^{70}$Zn, jj44b interaction in $^{2}p_{3/2}$, $^{1}f_{5/2}$, $^{2}p_{1/2}$ and $^{1}g_{9/2}$ space with $^{56}$Ni as the core is employed. However, for $^{80}$Se and $^{82}$Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for $^{70}$Zn. The above model space was used in many recent shell model and interacting boson model calculations for nuclei in this region. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are $1.1 \\times 10^{26}$ yr, $2.3 \\times 10^{27}$ yr and $2.2 \\times 10^{24}$ yr for $^{70}$Zn, $^{80}$Se and $^{82}$Se, respectively.

  20. N=(0, 2) Deformation of (2, 2) Sigma Models: Geometric Structure, Holomorphic Anomaly and Exact Beta Functions

    E-Print Network [OSTI]

    Jin Chen; Xiaoyi Cui; Mikhail Shifman; Arkady Vainshtein

    2014-07-27T23:59:59.000Z

    We study N=(0,2) deformed (2,2) two-dimensional sigma models. Such heterotic models were discovered previously on the world sheet of non-Abelian strings supported by certain four-dimensional N=1 theories. We study geometric aspects and holomorphic properties of these models, and derive a number of exact expressions for the beta functions in terms of the anomalous dimensions analogous to the NSVZ beta function in four-dimensional Yang-Mills. Instanton calculus provides a straightforward method for the derivation. The anomalous dimensions are calculated up to two loops implying that one of the beta functions is explicitly known up to three loops. The fixed point in the ratio of the couplings found previously at one loop is not shifted at two loops. We also consider the N=(0,2) supercurrent supermultiplet (the so-called hypercurrent) and its anomalies, as well as the "Konishi anomaly." This gives us another method for finding exact $\\beta$ functions. We prove that despite the chiral nature of the models under consideration quantum loops preserve isometries of the target space.

  1. PLASTIC DEFORMATIONPLASTIC DEFORMATION Modes of Deformation

    E-Print Network [OSTI]

    Subramaniam, Anandh

    PLASTIC DEFORMATIONPLASTIC DEFORMATION Modes of Deformation The Uniaxial Tension Test Mechanisms underlying Plastic Deformation Strengthening mechanisms Mechanical Metallurgy George E Dieter McClick here to know about all the mechanisms by which materials fail #12;Slip (Dislocation motion) Plastic

  2. Visco-elastic fluid simulations of coherent structures in strongly coupled dusty plasma medium

    SciTech Connect (OSTI)

    Singh Dharodi, Vikram; Kumar Tiwari, Sanat; Das, Amita, E-mail: amita@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2014-07-15T23:59:59.000Z

    A generalized hydrodynamic model depicting the behaviour of visco-elastic fluids has often been invoked to explore the behaviour of a strongly coupled dusty plasma medium below their crystallization limit. The model has been successful in describing the collective normal modes of the strongly coupled dusty plasma medium observed experimentally. The paper focuses on the study of nonlinear dynamical characteristic features of this model. Specifically, the evolution of coherent vorticity patches is being investigated here within the framework of this model. A comparison with Newtonian fluids and molecular dynamics simulations treating the dust species interacting through the Yukawa potential has also been presented.

  3. The Asperity-deformation Model Improvements and Its Applications to Velocity Inversion

    E-Print Network [OSTI]

    Bui, Hoa Q.

    2010-01-16T23:59:59.000Z

    . . . . . . . . . . . . . . . . . . . . . 2 1.2.1 Fracture modeling . . . . . . . . . . . . . . . . . . 3 1.2.2 Thelinkbetweenfracturecharacterizationand seismic data . . . . . . . . . . . . . . . . . . . . . 4 1.2.3 Seismic modeling of CO2 sequestration in frac- tured reservoirs... . . . . . . . . . . . . . . . . . . . 6 1.2.4 The influence of pressure . . . . . . . . . . . . . . 7 1.3 Research objectives . . . . . . . . . . . . . . . . . . . . 8 1.4 Dissertation outline . . . . . . . . . . . . . . . . . . . . 9 1.4.1 Chapter II - Theoretical study of the asperity...

  4. A Model for High-Strain-Rate Deformation of Uranium-Niobium Alloys

    SciTech Connect (OSTI)

    F.L.Addessio; Q.H.Zuo; T.A.Mason; L.C.Brinson

    2003-05-01T23:59:59.000Z

    A thermodynamic approach is used to develop a framework for modeling uranium-niobium alloys under the conditions of high strain rate. Using this framework, a three-dimensional phenomenological model, which includes nonlinear elasticity (equation of state), phase transformation, crystal reorientation, rate-dependent plasticity, and porosity growth is presented. An implicit numerical technique is used to solve the evolution equations for the material state. Comparisons are made between the model and data for low-strain-rate loading and unloading as well as for heating and cooling experiments. Comparisons of the model and data also are made for low- and high-strain-rate uniaxial stress and uniaxial strain experiments. A uranium-6 weight percent niobium alloy is used in the comparisons of model and experiment.

  5. Propagation and Retention of Viscoelastic Surfactants in Carbonate Cores 

    E-Print Network [OSTI]

    Yu, Meng

    2012-07-16T23:59:59.000Z

    Viscoelastic surfactant have found numerous application in the oil fields as fracturing and matrix acidizing fluid additives in the recent years. They have the ability to form long worm-like micelles with the increase in ...

  6. Nonlinear viscoelastic dynamics of nano-confined water

    E-Print Network [OSTI]

    Tai-De Li; Elisa Riedo

    2007-07-17T23:59:59.000Z

    The viscoelastic dynamics of nano-confined water is studied by means of atomic force microscopy (AFM). We observe a nonlinear viscoelastic behavior remarkably similar to that widely observed in metastable complex fluids. We show that the origin of the measured nonlinear viscoelasticity in nano-confined water is a strain rate dependent relaxation time and slow dynamics. By measuring the viscoelastic modulus at different frequencies and strains, we find that the intrinsic relaxation time of nano-confined water is in the range 0.1-0.0001 s, orders of magnitude longer than that of bulk water, and comparable to the dielectric relaxation time measured in supercooled water at 170-210 K.

  7. Deformed shell model results for neutrinoless double beta decay of nuclei in A=60-90 region

    E-Print Network [OSTI]

    R. Sahu; V. K. B. Kota

    2014-09-17T23:59:59.000Z

    Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay of $^{70}$Zn, $^{80}$Se and $^{82}$Se nuclei are calculated within the framework of the deformed shell model based on Hartree-Fock states. For $^{70}$Zn, jj44b interaction in $^{2}p_{3/2}$, $^{1}f_{5/2}$, $^{2}p_{1/2}$ and $^{1}g_{9/2}$ space with $^{56}$Ni as the core is employed. However, for $^{80}$Se and $^{82}$Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for $^{70}$Zn. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are $9.6 \\times 10^{25}$yr, $1.9 \\times 10^{27}$yr and $1.95 \\times 10^{24}$yr for $^{70}$Zn, $^{80}$Se and $^{82}$Se, respectively.

  8. Deformed shell model results for neutrinoless double beta decay of nuclei in A=60-90 region

    E-Print Network [OSTI]

    Sahu, R

    2014-01-01T23:59:59.000Z

    Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay of $^{70}$Zn, $^{80}$Se and $^{82}$Se nuclei are calculated within the framework of the deformed shell model based on Hartree-Fock states. For $^{70}$Zn, jj44b interaction in $^{2}p_{3/2}$, $^{1}f_{5/2}$, $^{2}p_{1/2}$ and $^{1}g_{9/2}$ space with $^{56}$Ni as the core is employed. However, for $^{80}$Se and $^{82}$Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for $^{70}$Zn. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are $9.6 \\times 10^{25}$yr, $1.9 \\times 10^{27}$yr and $1.95 \\times 10^{24}$yr for $^{70}$Zn, $^{80}$Se and $^{82}$Se, respectively.

  9. 3D Modeling of Coupled Rock Deformation and Thermo-Poro-Mechanical Processes in Fractures

    E-Print Network [OSTI]

    Rawal, Chakra

    2012-07-16T23:59:59.000Z

    and failure of weak planes of the formation with creation of new fractures, which impacts reservoir response. Incorporation of geomechanical factor into engineering analyses using fully coupled geomechanics-reservoir flow modeling exhibits computational...

  10. Viscoelastic transient of confined Red Blood Cells

    E-Print Network [OSTI]

    Gaël Prado; Alexander Farutin; Chaouqi Misbah; Lionel Bureau

    2014-09-17T23:59:59.000Z

    The unique ability of a red blood cell to flow through extremely small microcapillaries depends on the viscoelastic properties of its membrane. Here, we study in vitro the response time upon flow startup exhibited by red blood cells confined into microchannels. We show that the characteristic transient time depends on the imposed flow strength, and that such a dependence gives access to both the effective viscosity and the elastic modulus controlling the temporal response of red cells. A simple theoretical analysis of our experimental data, validated by numerical simulations, further allows us to compute an estimate for the two-dimensional membrane viscosity of red blood cells, $\\eta_{mem}^{2D}\\sim 10^{-7}$ N$\\cdot$s$\\cdot$m$^{-1}$. By comparing our results with those from previous studies, we discuss and clarify the origin of the discrepancies found in the literature regarding the determination of $\\eta_{mem}^{2D}$, and reconcile seemingly conflicting conclusions from previous works.

  11. Nonlinear viscoelastic characterization of thin films using dynamic mechanical analysis

    E-Print Network [OSTI]

    Payne, Debbie Flowers

    1993-01-01T23:59:59.000Z

    NONLINEAR VISCOELASTIC CHARACTERIZATION OF THIN FILMS USING DYNAMIC MECHANICAL ANALYSIS A Thesis by DEBBIE FLOWERS PAYNE 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 AUGUST 1993 Major Subject: Aerospace Engineering NONLINEAR VISCOELASTIC CHARACTERIZATION OF THIN FILMS USING DYNAMIC MECHANICAL ANALYSIS A Thesis by DEBBIE FLOWERS PAYNE Approved as to style and content by: Thomas W...

  12. Coupled Flow and Deformation Modeling of Carbon Dioxide Migration in the Presence of a Caprock Fracture during Injection

    SciTech Connect (OSTI)

    Siriwardane, Hema J.; Gondle, Raj K.; Bromhal, Grant S.

    2013-08-01T23:59:59.000Z

    Understanding the transport of carbon dioxide (CO{sub 2}) during long-term CO{sub 2} injection into a typical geologic reservoir, such as a saline aquifer, could be complicated because of changes in geochemical, hydrogeological, and hydromechanical behavior. While the caprock layer overlying the target aquifer is intended to provide a tight, impermeable seal in securing injected CO{sub 2}, the presence of geologic uncertainties, such as a caprock fracture or fault, may provide a channel for CO{sub 2} leakage. There could also be a possibility of the activation of a new or existing dormant fault or fracture, which could act as a leakage pathway. Such a leakage event during CO{sub 2} injection may lead to a different pressure and ground response over a period of time. In the present study, multiphase fluid flow simulations in porous media coupled with geomechanics were used to investigate the overburden geologic response and plume behavior during CO{sub 2} injection in the presence of a hypothetical permeable fractured zone in a caprock, existing or activated. Both single-phase and multiphase fluid flow simulations were performed. The CO{sub 2} migration through an existing fractured zone leads to changes in the fluid pressure in the overburden geologic layers and could have a significant impact on ground deformation behavior. Results of the study show that pressure signatures and displacement patterns are significantly different in the presence of a fractured zone in the caprock layer. The variation in pressure and displacement signatures because of the presence of a fractured zone in the caprock at different locations may be useful in identifying the presence of a fault/fractured zone in the caprock. The pressure signatures can also serve as a mechanism to identify the activation of leakage pathways through the caprock during CO{sub 2} injection. Pressure response and ground deformation behavior from sequestration modeling could be useful in the development of smart technologies to monitor safe CO{sub 2} storage and understand CO{sub 2} transport, with limited field instrumentation.

  13. Experimental investigation and constitutive modeling of the large deformation behavior of anisotropic steel sheets undergoing strain-induced phase transformation

    E-Print Network [OSTI]

    Beese, Allison M

    2011-01-01T23:59:59.000Z

    The strain-induced phase transformation from austenite to martensite is responsible for the high strength and ductility of TRansformation-Induced Plasticity (TRIP)- assisted steels. The large deformation behavior of ...

  14. Evolution of shock instability in granular gases with viscoelastic collisions

    E-Print Network [OSTI]

    Nick Sirmas; Matei Radulescu

    2014-09-04T23:59:59.000Z

    Shocks in granular media have been shown to develop instabilities. We address the role that early stages of shock development have on this type of instability. We look at the evolution of shock waves driven by a piston in a dilute system of smooth inelastic disks, using both discrete-particle and continuum modelling. To mimic a realistic granular gas, viscoelastic collisions are approximated with an impact velocity threshold $u^*$ needed for inelastic collisions to occur. We show that behaviour of the shock evolution is dependent on the ratio of piston velocity to impact velocity threshold $u_p/u^*$, and the coefficient of restitution $\\varepsilon$. For $u_p/u^*=2.0$, we recover shock evolution behaving similar to that observed in purely inelastic media. This is characterized by a short period where the shock front pulls towards the piston before attaining a developed structure. No pullback is seen for $u_p/u^*=1.0$. Results show the onset of instability for these stronger shocks during this evolving stage. These results suggest that the early stages of shock evolution play an important role in the shock instability.

  15. Direct Rendering of Deformable Volume Data Shiaofen Fang

    E-Print Network [OSTI]

    Fang, Shiaofen

    Direct Rendering of Deformable Volume Data Shiaofen Fang Department of Computer and Information In this paper, we present a new deformable volume rendering algorithm. The volume deformation is modeled to directly render the deformed volume without going through the expensive volume construction process

  16. Rolling friction for hard cylinder and sphere on viscoelastic solid

    E-Print Network [OSTI]

    B. N. J. Persson

    2010-08-26T23:59:59.000Z

    We calculate the friction force acting on a hard cylinder or spherical ball rolling on a flat surface of a viscoelastic solid. The rolling friction coefficient depends non-linearly on the normal load and the rolling velocity. For a cylinder rolling on a viscoelastic solid characterized by a single relaxation time Hunter has obtained an exact result for the rolling friction, and our result is in very good agreement with his result for this limiting case. The theoretical results are also in good agreement with experiments of Greenwood and Tabor. We suggest that measurements of rolling friction over a wide range of rolling velocities and temperatures may constitute an useful way to determine the viscoelastic modulus of rubber-like materials.

  17. Guided Wave Propagation in Tubular Section with Multi-Layered Viscoelastic Coating

    E-Print Network [OSTI]

    Kuo, Chi-Wei 1982-

    2012-11-16T23:59:59.000Z

    cross-section of the pipe. The layer between radii r1 and r2 is elastic. The outer layer between radii r2 and r3 is the viscoelastic coating material. The axial direction of the cylinder is along the z-axis. The circumferential direction is defined... by the ?-axis. Fig. 2.1 Pipe model Fig. 2.2 Pipe cross-section 2.1. Longitudinal Wave along Axial Direction The Lame-Navier equation of motion for isotropic materials is 2 2 2( ) ( ) ( / )? ? ? ?? + + ? ?? = ? ? tu u u (2.1) r3 r2 r1...

  18. Numerical simulation of the non-isothermal developing flow of a nonlinear viscoelastic fluid in a rectangular channel

    E-Print Network [OSTI]

    Nikoleris, Teo

    1988-01-01T23:59:59.000Z

    Fluid in a Rectangular Channel (December 1988) Teo Nikoleris, B. S. , Reed College Chairman of Advisory Committee: Dr. R. Darby An orthogonal collocation finite element program was used to numerically model the hydrodynamicslly and thermally... in negligible increase of Nw~ ~?. Also, the approach of Chang and Finlayson [6], [7] who applied orthogonal collocation finite elements in conjunction with bicubic Hermitian polynomials to approximate various viscoelastic flow problems, also met with little...

  19. Analysis, comparison, and modeling of radar interferometry, date of surface deformation signals associated with underground explosions, mine collapses and earthquakes. Phase I: underground explosions, Nevada Test Site

    SciTech Connect (OSTI)

    Foxall, W; Vincent, P; Walter, W

    1999-07-23T23:59:59.000Z

    We have previously presented simple elastic deformation modeling results for three classes of seismic events of concern in monitoring the CTBT--underground explosions, mine collapses and earthquakes. Those results explored the theoretical detectability of each event type using synthetic aperture radar interferometry (InSAR) based on commercially available satellite data. In those studies we identified and compared the characteristics of synthetic interferograms that distinguish each event type, as well the ability of the interferograms to constrain source parameters. These idealized modeling results, together with preliminary analysis of InSAR data for the 1995 mb 5.2 Solvay mine collapse in southwestern Wyoming, suggested that InSAR data used in conjunction with regional seismic monitoring holds great potential for CTBT discrimination and seismic source analysis, as well as providing accurate ground truth parameters for regional calibration events. In this paper we further examine the detectability and ''discriminating'' power of InSAR by presenting results from InSAR data processing, analysis and modeling of the surface deformation signals associated with underground explosions. Specifically, we present results of a detailed study of coseismic and postseismic surface deformation signals associated with underground nuclear and chemical explosion tests at the Nevada Test Site (NTS). Several interferograms were formed from raw ERS-1/2 radar data covering different time spans and epochs beginning just prior to the last U.S. nuclear tests in 1992 and ending in 1996. These interferograms have yielded information about the nature and duration of the source processes that produced the surface deformations associated with these events. A critical result of this study is that significant post-event surface deformation associated with underground nuclear explosions detonated at depths in excess of 600 meters can be detected using differential radar interferometry. An immediate implication of this finding is that underground nuclear explosions may not need to be captured coseismically by radar images acquired before and after an event in order to be detectable. This has obvious advantages in CTBT monitoring since suspect seismic events--which usually can be located within a 100 km by 100 km area of an ERS-1/2 satellite frame by established seismic methods-can be imaged after the event has been identified and located by existing regional seismic networks. Key Words: InSAR, SLC images, interferogram, synthetic interferogram, ERS-1/2 frame, phase unwrapping, DEM, coseismic, postseismic, source parameters.

  20. Dynamics of multiple viscoelastic carbon nanotube based nanocomposites with axial magnetic field

    SciTech Connect (OSTI)

    Karli?i?, Danilo; Caji?, Milan [Mathematical Institute of the SASA, Kneza Mihaila 36, Belgrade 11001 (Serbia); Murmu, Tony [School of Engineering, University of the West of Scotland, Paisley PA12BE (United Kingdom); Kozi?, Predrag [Faculty of Mechanical Engineering, University of Niš, A. Medvedeva 14, 18000 Niš (Serbia); Adhikari, Sondipon [College of Engineering, Swansea University, Singleton Park, Swansea SA2 8PP (United Kingdom)

    2014-06-21T23:59:59.000Z

    Nanocomposites and magnetic field effects on nanostructures have received great attention in recent years. A large amount of research work was focused on developing the proper theoretical framework for describing many physical effects appearing in structures on nanoscale level. Great step in this direction was successful application of nonlocal continuum field theory of Eringen. In the present paper, the free transverse vibration analysis is carried out for the system composed of multiple single walled carbon nanotubes (MSWCNT) embedded in a polymer matrix and under the influence of an axial magnetic field. Equivalent nonlocal model of MSWCNT is adopted as viscoelastically coupled multi-nanobeam system (MNBS) under the influence of longitudinal magnetic field. Governing equations of motion are derived using the Newton second low and nonlocal Rayleigh beam theory, which take into account small-scale effects, the effect of nanobeam angular acceleration, internal damping and Maxwell relation. Explicit expressions for complex natural frequency are derived based on the method of separation of variables and trigonometric method for the “Clamped-Chain” system. In addition, an analytical method is proposed in order to obtain asymptotic damped natural frequency and the critical damping ratio, which are independent of boundary conditions and a number of nanobeams in MNBS. The validity of obtained results is confirmed by comparing the results obtained for complex frequencies via trigonometric method with the results obtained by using numerical methods. The influence of the longitudinal magnetic field on the free vibration response of viscoelastically coupled MNBS is discussed in detail. In addition, numerical results are presented to point out the effects of the nonlocal parameter, internal damping, and parameters of viscoelastic medium on complex natural frequencies of the system. The results demonstrate the efficiency of the suggested methodology to find the closed form solutions for the free vibration response of multiple nanostructure systems under the influence of magnetic field.

  1. Deforming Meyer sets

    E-Print Network [OSTI]

    Jeong-Yup Lee; Robert V. Moody

    2009-10-23T23:59:59.000Z

    A linear deformation of a Meyer set $M$ in $\\RR^d$ is the image of $M$ under a group homomorphism of the group $[M]$ generated by $M$ into $\\RR^d$. We provide a necessary and sufficient condition for such a deformation to be a Meyer set. In the case that the deformation is a Meyer set and the deformation is injective, the deformation is pure point diffractive if the orginal set $M$ is pure point diffractive.

  2. Propagation and Retention of Viscoelastic Surfactants in Carbonate Cores

    E-Print Network [OSTI]

    Yu, Meng

    2012-07-16T23:59:59.000Z

    Viscoelastic surfactant have found numerous application in the oil fields as fracturing and matrix acidizing fluid additives in the recent years. They have the ability to form long worm-like micelles with the increase in pH and calcium concentration...

  3. Helicobacter pylori moves through mucus by reducing mucin viscoelasticity

    E-Print Network [OSTI]

    Helicobacter pylori moves through mucus by reducing mucin viscoelasticity Jonathan P. Celli: 20 pages 6 figures 0 tables. #12;Abstract The ulcer-causing gastric pathogen Helicobacter pylori is wrong. #12;\\body Introduction Helicobacter pylori is a spiral shaped, Gram-negative microorganism

  4. Helicobacter pylori moves through mucus by reducing mucin viscoelasticity

    E-Print Network [OSTI]

    Helicobacter pylori moves through mucus by reducing mucin viscoelasticity Jonathan P. Cellia,1, 2009 (received for review March 27, 2009) The ulcer-causing gastric pathogen Helicobacter pylori environment. H. pylori bacterial motility rheology pH gelation Helicobacter pylori is a spiral shaped, Gram

  5. Changes in Large Pulmonary Arterial Viscoelasticity in Chronic Pulmonary Hypertension

    E-Print Network [OSTI]

    Lakes, Roderic

    Changes in Large Pulmonary Arterial Viscoelasticity in Chronic Pulmonary Hypertension Zhijie Wang1 of pulmonary arterial hypertension (PAH) and is an excellent predictor of mortality due to right ventricular at a physiologically relevant frequency (10 Hz) in hypertensive PAs. The dynamic elastic modulus (E), a material

  6. Viscoelastic Properties of an Epoxy Resin during Cure

    E-Print Network [OSTI]

    Mather, Patrick T.

    Viscoelastic Properties of an Epoxy Resin during Cure DANIEL J. O'BRIEN1 Department of Mechanical: The cure dependent relaxation modulus of an epoxy resin was investigated over the entire range of cure as well as thermal asymmetry can result in uneven curing of the part. Second, epoxy resins can shrink

  7. RESEARCH ARTICLE Bubble growth in visco-elastic magma: implications

    E-Print Network [OSTI]

    Lyakhovsky, Vladimir

    RESEARCH ARTICLE Bubble growth in visco-elastic magma: implications to magma fragmentation modulus, bubble growth is slow and follows an exponential law in a viscous growth regime, while for low friction and the Mohr-Coulomb failure theory, and a strain related one based on fibre elongation

  8. Non-contact Method in Measuring the Viscoelastic

    E-Print Network [OSTI]

    Petta, Jason

    to be considered for effective usage in such applications Polymer solar cells Membranes 1Wikimedia Commons, Solar Cells 2Science Centric, Polymer Membranes 1 2 #12;Viscoelasticity · Has both viscous and elastic-off Experiment Modification of original blow-off setup: temperature control #12;Temperature Calibration · Upper

  9. A time integration scheme for stress - temperature dependent viscoelastic behaviors of isotropic materials

    E-Print Network [OSTI]

    Khan, Kamran-Ahmed

    2009-05-15T23:59:59.000Z

    solutions within a general displacement based FE structural analyses for small deformations and uncoupled thermo-mechanical problems. A previously developed recursive-iterative algorithm for a stress-dependent hereditary integral model which was developed...

  10. ANALYSES OF DEFORMATION IN VISCOELASTIC SANDWICH COMPOSITES SUBJECT TO MOISTURE DIFFUSION

    E-Print Network [OSTI]

    Joshi, Nikhil P.

    2010-01-16T23:59:59.000Z

    Sandwich composites with polymer foam core are currently used in load-bearing components in buildings and naval structures due to their high strength to weight and stiffness to weight ratios, excellent thermal insulation, and ease of manufacturing...

  11. On study of nonlinear viscoelastic behavior of red blood cell membrane

    E-Print Network [OSTI]

    Horacio Castellini; Bibiana Riquelme; Patricia Foresto

    2007-03-15T23:59:59.000Z

    The linear viscoelastic behavior of the red blood cell membrane of mammal and human was studied in previous works proposing different experimental methods to determine their viscoelastic parameters. In the present work the nonlinear component of dynamic viscosity of the red blood cell membrane by nonlinear time series analysis is used. For such aim, it obtained time series of test in vitro of samples of humans and rats red blood cells using the Erythrodeformeter in oscillating regime. The signal filtrate suppresses any linear behavior as well as represented by a system of linear ordinary differential equations. The test shown as much in humans as in rats resonance frequencies associated to an attractor of unknown nature independently of excitation in the physiological range. The preliminary studies shown that attractor could be correspond to a complex form bull. These results allow to extend the present knowledge on dynamic of the cellular membrane to similar stimulus which happens in the blood circulation and it will allows to make better models of the same one.

  12. Integrable Deformations of Strings on Symmetric Spaces

    E-Print Network [OSTI]

    Timothy J. Hollowood; J. Luis Miramontes; David M. Schmidtt

    2014-07-16T23:59:59.000Z

    A general class of deformations of integrable sigma-models with symmetric space F/G target-spaces are found. These deformations involve defining the non-abelian T dual of the sigma-model and then replacing the coupling of the Lagrange multiplier imposing flatness with a gauged F/F WZW model. The original sigma-model is obtained in the limit of large level. The resulting deformed theories are shown to preserve both integrability and the equations-of-motion, but involve a deformation of the symplectic structure. It is shown that this deformed symplectic structure involves a linear combination of the original Poisson bracket and a generalization of the Faddeev-Reshetikhin Poisson bracket which we show can be re-expressed as two decoupled F current algebras. It is then shown that the deformation can be incorporated into the classical model of strings on R x F/G via a generalization of the Pohlmeyer reduction. In this case, in the limit of large sigma-model coupling it is shown that the theory becomes the relativistic symmetric space sine-Gordon theory. These results point to the existence of a deformation of this kind for the full Green-Schwarz superstring on AdS5 x S5.

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

    SciTech Connect (OSTI)

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

    2010-07-01T23:59:59.000Z

    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.

  14. A thin film model for corotational Jeffreys fluids under strong slip

    E-Print Network [OSTI]

    A. Münch; B. Wagner; M. Rauscher; R. Blossey

    2006-05-14T23:59:59.000Z

    We derive a thin film model for viscoelastic liquids under strong slip which obey the stress tensor dynamics of corotational Jeffreys fluids.

  15. A fast multipole boundary element method for 2D viscoelastic problems X.Y. Zhu a,d

    E-Print Network [OSTI]

    Liu, Yijun

    A fast multipole boundary element method for 2D viscoelastic problems X.Y. Zhu a,d , W.Q. Chen b Available online 21 August 2010 Keywords: Boundary element method Fast multipole method Viscoelasticity Multi-inclusion composite a b s t r a c t A fast multipole formulation for 2D linear viscoelastic

  16. IBA in deformed nuclei

    SciTech Connect (OSTI)

    Casten, R.F.; Warner, D.D.

    1982-01-01T23:59:59.000Z

    The structure and characteristic properties and predictions of the IBA in deformed nuclei are reviewed, and compared with experiment, in particular for /sup 168/Er. Overall, excellent agreement, with a minimum of free parameters (in effect, two, neglecting scale factors on energy differences), was obtained. A particularly surprising, and unavoidable, prediction is that of strong ..beta.. ..-->.. ..gamma.. transitions, a feature characteristically absent in the geometrical model, but manifest empirically. Some discrepancies were also noted, principally for the K=4 excitation, and the detailed magnitudes of some specific B(E2) values. Considerable attention is paid to analyzing the structure of the IBA states and their relation to geometric models. The bandmixing formalism was studied to interpret both the aforementioned discrepancies and the origin of the ..beta.. ..-->.. ..gamma.. transitions. The IBA states, extremely complex in the usual SU(5) basis, are transformed to the SU(3) basis, as is the interaction Hamiltonian. The IBA wave functions appear with much simplified structure in this way as does the structure of the associated B(E2) values. The nature of the symmetry breaking of SU(3) for actual deformed nuclei is seen to be predominantly ..delta..K=0 mixing. A modified, and more consistent, formalism for the IBA-1 is introduced which is simpler, has fewer free parameters (in effect, one, neglecting scale factors on energy differences), is in at least as good agreement with experiment as the earlier formalism, contains a special case of the 0(6) limit which corresponds to that known empirically, and appears to have a close relationship to the IBA-2. The new formalism facilitates the construction of contour plots of various observables (e.g., energy or B(E2) ratios) as functions of N and chi/sub Q/ which allow the parameter-free discussion of qualitative trajectories or systematics.

  17. Measurement of Local Viscoelasticity and Forces in Living Cells by Magnetic Tweezers

    E-Print Network [OSTI]

    Bausch, Andreas

    Measurement of Local Viscoelasticity and Forces in Living Cells by Magnetic Tweezers Andreas R measured the viscoelastic properties of the cytoplasm of J774 macrophages with a recently developed circuit, we measured the shear elastic modulus, the effective viscosities, and the strain relaxation time

  18. Deformed proton emitters.

    SciTech Connect (OSTI)

    Carpenter, M. P.; Cizewski, J. A.; Davids, C. N.; Davinson, T.; Fotiades, N.; Henderson, D. J.; Janssens, R. V. F.; Lauritsen, T.; Reiter, P.; Ressler, J. J.; Schwartz, J.; Seweryniak, D.; Sonzogni, A. A.; Uusitalok, J.; Walters, W. B.; Wiedenhover, I. L.; Woods, P. J.

    1999-02-17T23:59:59.000Z

    The mechanisms of proton radioactivity from deformed rare earth nuclei are discussed and preliminary results on the fine structure decay of {sup 131}Eu are presented.

  19. Instantiating deformable models with a neural net Christopher K. I. Williams \\Lambda , Michael Revow, Geoffrey E. Hinton

    E-Print Network [OSTI]

    Edinburgh, University of

    '' or ``compiling down'' the results of previous searches to speed up running time. This paper is structured models are an attractive approach to recognizing objects which have considerable within­class variability such as handwritten characters. However, there are severe search problems associated with fitting the models to data

  20. Evolution of deformations in medium-mass nuclei

    E-Print Network [OSTI]

    H. Sagawa; X. R. Zhou; X. Z. Zhang

    2005-10-28T23:59:59.000Z

    Evolution of quadrupole deformations in $sd$ and $pf$ shell nuclei with mass A= 18$\\sim$56 is studied by using deformed Skyrme Hartree-Fock (HF) model with pairing correlations. We point out that the quadrupole deformations of the nuclei with the isospin T=0 and T=1 show strong mass number dependence as a clear manifestation of dynamical evolution of deformation in nuclear many-body systems. The competition between the deformation driving particle-vibration coupling and the closed shell structure is shown in a systematic study of the ratios between the proton and neutron deformations in nuclei with T=$|$T$_z|$=1. Calculated quadrupole and hexadecapole deformations are compared with shell model results and available experimental data. A relation between the skin thickness and the intrinsic Q$_2$ moments is also discussed.

  1. Analysis of Refrigerant Flow and Deformation for a Flexible Short-Tube using a Finite Element Model

    E-Print Network [OSTI]

    O'Neal, D.L.; Bassiouny, R.

    reliability. Short-tubes have either a constant inner dia- meter flow channel or a tapered channel with a smallAbstract A finite element model was used to simulate single-phase flow of R-22 through flexible short-tubes. The numerical model included the fluid... in the flow area. The more flexible (5513 kPa) short-tube restricted the mass flow rate more than the most rigid (9889 kPa) short-tube used in this study. The mass flow rates estimated with the finite element model were as much as 14% higher than those from...

  2. Resurgent deformation quantisation

    SciTech Connect (OSTI)

    Garay, Mauricio, E-mail: garay91@gmail.com [Institut für Mathematik, FB 08 Physik, Mathematik und Informatik, Johannes Gutenberg-Universität, 55099 Mainz (Germany)] [Institut für Mathematik, FB 08 Physik, Mathematik und Informatik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Goursac, Axel de, E-mail: Axelmg@melix.net [Chargé de Recherche au F.R.S.-FNRS, IRMP, Université Catholique de Louvain, Chemin du Cyclotron, 2, B-1348 Louvain-la-Neuve (Belgium); Straten, Duco van, E-mail: straten@mathematik.uni-mainz.de [Institut für Mathematik, FB 08 Physik, Mathematik und Informatik, Johannes Gutenberg-Universität, 55099 Mainz (Germany)

    2014-03-15T23:59:59.000Z

    We construct a version of the complex Heisenberg algebra based on the idea of endless analytic continuation. The algebra would be large enough to capture quantum effects that escape ordinary formal deformation quantisation. -- Highlights: •We construct resurgent deformation quantisation. •We give integral formulæ. •We compute examples which show that hypergeometric functions appear naturally in quantum computations.

  3. Deformation Analysis of Sand Specimens using 3D Digital Image Correlation for the Calibration of an Elasto-Plastic Model

    E-Print Network [OSTI]

    Song, Ahran

    2012-10-19T23:59:59.000Z

    and softening laws. In addition, a two-dimensional axisymmetric finite element model was built to simulate the actual experimental conditions, including both the global and local kinematics effects captured by 3D digital image correlation analysis...

  4. 4D RECONSTRUCTIONS FROM LOW-COUNT SPECT DATA USING DEFORMABLE MODELS WITH SMOOTH INTERIOR INTENSITY VARIATIONS

    SciTech Connect (OSTI)

    G. S. CUNNINGHAM; A. LEHOVICH

    2000-01-01T23:59:59.000Z

    The Bayes Inference Engine (BIE) has been used to perform a 4D reconstruction of a first-pass radiotracer bolus distribution inside a CardioWest Total Artificial Heart, imaged with the University of Arizona's FastSPECT system. The BIE estimates parameter values that define the 3D model of the radiotracer distribution at each of 41 times spanning about two seconds. The 3D models have two components: a closed surface, composed of hi-quadratic Bezier triangular surface patches, that defines the interface between the part of the blood pool that contains radiotracer and the part that contains no radiotracer, and smooth voxel-to-voxel variations in intensity within the closed surface. Ideally, the surface estimates the ventricular wall location where the bolus is infused throughout the part of the blood pool contained by the right ventricle. The voxel-to-voxel variations are needed to model an inhomogeneously-mixed bolus. Maximum a posterior (MAP) estimates of the Bezier control points and voxel values are obtained for each time frame. We show new reconstructions using the Bezier surface models, and discuss estimates of ventricular volume as a function of time, ejection fraction, and wall motion. The computation time for our reconstruction process, which directly estimates complex 3D model parameters from the raw data, is performed in a time that is competitive with more traditional voxel-based methods (ML-EM, e.g.).

  5. Tumor Tracking Method Based on a Deformable 4D CT Breathing Motion Model Driven by an External Surface Surrogate

    SciTech Connect (OSTI)

    Fassi, Aurora, E-mail: aurora.fassi@mail.polimi.it [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Schaerer, Joël; Fernandes, Mathieu [CREATIS, CNRS UMR 5220, INSERM U1044, Université Lyon 1, INSA-Lyon, Villeurbanne (France); Department of Radiotherapy, Centre Léon Bérard, Lyon (France); Riboldi, Marco [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Bioengineering Unit, CNAO Foundation, Pavia (Italy); Sarrut, David [CREATIS, CNRS UMR 5220, INSERM U1044, Université Lyon 1, INSA-Lyon, Villeurbanne (France); Department of Radiotherapy, Centre Léon Bérard, Lyon (France); Baroni, Guido [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Bioengineering Unit, CNAO Foundation, Pavia (Italy)

    2014-01-01T23:59:59.000Z

    Purpose: To develop a tumor tracking method based on a surrogate-driven motion model, which provides noninvasive dynamic localization of extracranial targets for the compensation of respiration-induced intrafraction motion in high-precision radiation therapy. Methods and Materials: The proposed approach is based on a patient-specific breathing motion model, derived a priori from 4-dimensional planning computed tomography (CT) images. Model parameters (respiratory baseline, amplitude, and phase) are retrieved and updated at each treatment fraction according to in-room radiography acquisition and optical surface imaging. The baseline parameter is adapted to the interfraction variations obtained from the daily cone beam (CB) CT scan. The respiratory amplitude and phase are extracted from an external breathing surrogate, estimated from the displacement of the patient thoracoabdominal surface, acquired with a noninvasive surface imaging device. The developed method was tested on a database of 7 lung cancer patients, including the synchronized information on internal and external respiratory motion during a CBCT scan. Results: About 30 seconds of simultaneous acquisition of CBCT and optical surface images were analyzed for each patient. The tumor trajectories identified in CBCT projections were used as reference and compared with the target trajectories estimated from surface displacement with the a priori motion model. The resulting absolute differences between the reference and estimated tumor motion along the 2 image dimensions ranged between 0.7 and 2.4 mm; the measured phase shifts did not exceed 7% of the breathing cycle length. Conclusions: We investigated a tumor tracking method that integrates breathing motion information provided by the 4-dimensional planning CT with surface imaging at the time of treatment, representing an alternative approach to point-based external–internal correlation models. Although an in-room radiograph-based assessment of the reliability of the motion model is envisaged, the developed technique does not involve the estimation and continuous update of correlation parameters, thus requiring a less intense use of invasive imaging.

  6. A comparison of viscoelastic stress wakes for 2D and 3D Newtonian drop deformation in a viscoelastic matrix under shear

    E-Print Network [OSTI]

    Renardy, Yuriko

    ], Webster [We2], Faran [Fa1], and Cima-Suffridge [CS1]. In the first part of this thesis (Chapter 2), we

  7. Analysis of Refrigerant Flow and Deformation for a Flexible Short-Tube using a Finite Element Model 

    E-Print Network [OSTI]

    O'Neal, D.L.; Bassiouny, R.

    2004-01-01T23:59:59.000Z

    an short-tube using a finite element model International Journal of Refrig Vol 27 No 2, pp. 176-183The short-tube is used by United States heat pump manufactures as an expansion device because of its lowAnalyse de l’e´coulement d’un frigorige`ne et...

  8. Thermomechanical Constitutive Modeling of Viscoelastic Materials undergoing Degradation

    E-Print Network [OSTI]

    Karra, Satish

    2012-07-16T23:59:59.000Z

    .s, kD = 1:2 10 6 s 1 , = 10, = 0:3, = 0:5. : : : : : : : : : : : : : : : : : : : : : : : : 174 xviii FIGURE Page 36 Engineering spatial convergence of the solution for p at Z? = 0 and at t? = 0:5. The time-step was chosen to be t? = 0...

  9. Finite Element Analyses of a Cyclically Loaded Linear Viscoelastic Biodegradable Stent

    E-Print Network [OSTI]

    Murphy, Jason Kyle

    2014-12-03T23:59:59.000Z

    degradation behaviors on the performance of cylindrical annuli that mimic stents under cyclic loadings is examined. Two polymers are considered: poly-L-lactic acid (PLLA) and polyoxymethylene (POM). A numerical algorithm for an isotropic, linear, viscoelastic...

  10. A Viscoelastic-Viscoplastic Analysis of Fiber Reinforced Polymer Composites Undergoing Mechanical Loading and Temperature Changes 

    E-Print Network [OSTI]

    Jeon, Jaehyeuk

    2013-08-09T23:59:59.000Z

    This study presents a combined viscoelastic (VE)-viscoplastic (VP) analysis for Fiber Reinforced Polymer (FRP) composites subject to simultaneous mechanical load and conduction of heat. The studied FRP composites consist of unidirectional fibers...

  11. Guided Wave Propagation in Tubular Section with Multi-Layered Viscoelastic Coating 

    E-Print Network [OSTI]

    Kuo, Chi-Wei 1982-

    2012-11-16T23:59:59.000Z

    Three kinds of propagating waves physically admissible in a tubular section are derived to establish their dispersion characteristics in response to the presence of multi-layered viscoelastic coatings. One is the longitudinal wave that propagates...

  12. Impact of Fe (III) on the Performance of Viscoelastic Surfactant-Based Acids 

    E-Print Network [OSTI]

    Shu, Yi

    2013-08-02T23:59:59.000Z

    Viscoelastic surfactant (VES)-based acid systems have been used successfully in matrix and acid fracturing treatments. However, the existence of Fe (III) as a contaminant in such systems may lead to many problems, due to interactions between VES...

  13. Characterization of the viscoelastic properties of thin-film materials using dynamic-mechanical testing techniques 

    E-Print Network [OSTI]

    Biskup, Bruce Allen

    1994-01-01T23:59:59.000Z

    An investigation into the use of dynamic mechanical analysis to characterize the viscoelastic properties of thin film materials is presented. The methodology was investigated using polyethylene films used on high altitude research balloons. Time...

  14. Correlation of mechanical viscoelastic properties to microstructure of equine cortical bone tissue 

    E-Print Network [OSTI]

    Ayers, Andrew Kerr

    1995-01-01T23:59:59.000Z

    Dynamic Mechanical Analysis (DMA) has long been used as a method of determining viscoelastic mechanical properties of polymeric materials. More recently, DMA has been used for characterizing the fiber/matrix interface in composite materials...

  15. A Multi-scale Framework for Thermo-viscoelastic Analysis of Fiber Metal Laminates

    E-Print Network [OSTI]

    Sawant, Sourabh P.

    2010-01-14T23:59:59.000Z

    Fiber Metal Laminates (FML) are hybrid composites with alternate layers of orthotropic fiber reinforced polymers (FRP) and isotropic metal alloys. FML can exhibit a nonlinear thermo-viscoelastic behavior under the influence of external mechanical...

  16. Nonlinear viscoelastic behaviors of multilayered (pultruded) composites at various temperatures and stresses

    E-Print Network [OSTI]

    Muddasani, Maithri

    2009-05-15T23:59:59.000Z

    This study presents experimental works and finite element (FE) analyses for understanding nonlinear thermo-viscoelastic behaviors of multilayered (pultruded) composites under tension. Uniaxial isothermal creep tests in tension are conducted...

  17. Impact of Fe (III) on the Performance of Viscoelastic Surfactant-Based Acids

    E-Print Network [OSTI]

    Shu, Yi

    2013-08-02T23:59:59.000Z

    Viscoelastic surfactant (VES)-based acid systems have been used successfully in matrix and acid fracturing treatments. However, the existence of Fe (III) as a contaminant in such systems may lead to many problems, due to interactions between VES...

  18. Pre-Stressed Viscoelastic Composites: Effective Incremental Moduli and Band-Gap Tuning

    SciTech Connect (OSTI)

    Parnell, William J. [School of Mathematics, Alan Turing Building, University of Manchester, Manchester, M13 9PL (United Kingdom)

    2010-09-30T23:59:59.000Z

    We study viscoelastic wave propagation along pre-stressed nonlinear elastic composite bars. In the pre-stressed state we derive explicit forms for the effective incremental storage and loss moduli with dependence on the pre-stress. We also derive a dispersion relation for the effective wavenumber in the case of arbitrary frequency, hence permitting a study of viscoelastic band-gap tuning via pre-stress.

  19. Nonlinear viscoelastic characterization of AS-3502 graphite/epoxy composite material 

    E-Print Network [OSTI]

    Kerstetter, Michael Scott

    1980-01-01T23:59:59.000Z

    NONLINEAR VISCOELASTIC CHARACTERIZATION OF AS-3502 GRAPHITE/EPOXY COMPOSITE MATERIAL A Thesis MICHAEL SCOTT KERSTETTER Submitted to the Graduate College of Texas A8M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1980 Major Subject: Aerospace Engineering NONLINEAR VISCOELASTIC CHARACTERIZATION OF AS-3502 GRAPHITE/EPOXY COMPOSITE MATERIAL A Thesis by MICHAEL SCOTT KERSTETTER Approved as to style and content by: Dr. Kenneth L...

  20. On deformation twinning in a 17.5%Mn-TWIP steel: A physically...

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

    On deformation twinning in a 17.5%Mn-TWIP steel: A physically-based phenomenological model. On deformation twinning in a 17.5%Mn-TWIP steel: A physically-based phenomenological...

  1. A phase field approach for optimal boundary control of damage processes in two-dimensional viscoelastic media

    E-Print Network [OSTI]

    M. Hassan Farshbaf-Shaker; Christian Heinemann

    2015-02-10T23:59:59.000Z

    In this work we investigate a phase field model for damage processes in two-dimensional viscoelastic media with nonhomogeneous Neumann data describing external boundary forces. In the first part we establish global-in-time existence, uniqueness, a priori estimates and continuous dependence of strong solutions on the data. The main difficulty is caused by the irreversibility as well as boundedness of the phase field variable which results in a doubly constrained PDE system. In the last part we consider an optimal control problem where a cost functional penalizes maximal deviations from prescribed damage profiles. The goal is to minimize the cost functional with respect to exterior forces acting on the boundary which play the role of the control variable in the considered model. To this end, we prove existence of minimizers and study a family of "local" approximations via adapted cost functionals.

  2. Electrically Deformable Liquid Marbles

    E-Print Network [OSTI]

    Edward Bormashenko; Roman Pogreb; Tamir Stein; Gene Whyman; Marcelo Schiffer; Doron Aurbach

    2011-02-17T23:59:59.000Z

    Liquid marbles, which are droplets coated with a hydrophobic powder, were exposed to a uniform electric field. It was established that a threshold value of the electric field, 15 cgse, should be surmounted for deformation of liquid marbles. The shape of the marbles was described as a prolate spheroid. The semi-quantitative theory describing deformation of liquid marbles in a uniform electric field is presented. The scaling law relating the radius of the contact area of the marble to the applied electric field shows a satisfactory agreement with the experimental data.

  3. Nanolaminate deformable mirrors

    DOE Patents [OSTI]

    Papavasiliou, Alexandros P. (Oakland, CA); Olivier, Scot S. (Santa Cruz, CA)

    2009-04-14T23:59:59.000Z

    A deformable mirror formed out of two layers of a nanolaminate foil attached to a stiff substrate is introduced. Deformation is provided by an electrostatic force between two of the layers. The internal stiffness of the structure allows for high-spatial-frequency shapes. The nanolaminate foil of the present invention allows for a high-quality mirror surface. The device achieves high precision in the vertical direction by using foils with accurately controlled thicknesses, but does not require high precision in the lateral dimensions, allowing such mirrors to be fabricated using crude lithography techniques. Such techniques allow structures up to about the meter scale to be fabricated.

  4. Nanolaminate deformable mirrors

    SciTech Connect (OSTI)

    Papavasiliou, Alexandros P.; Olivier, Scot S.

    2010-04-06T23:59:59.000Z

    A deformable mirror formed out of two layers of a nanolaminate foil attached to a stiff substrate is introduced. Deformation is provided by an electrostatic force between two of the layers. The internal stiffness of the structure allows for high-spatial-frequency shapes. The nanolaminate foil of the present invention allows for a high-quality mirror surface. The device achieves high precision in the vertical direction by using foils with accurately controlled thicknesses, but does not require high precision in the lateral dimensions, allowing such mirrors to be fabricated using crude lithography techniques. Such techniques allow structures up to about the meter scale to be fabricated.

  5. Mesh Puppetry: Cascading Optimization of Mesh Deformation with Inverse Kinematics

    E-Print Network [OSTI]

    Zhou, Kun

    approach builds upon traditional rigging by optimizing skeleton position and vertex weights. Keywords: Mesh deformation, nonlinear optimization, inverse kinematics, geometry processing. 1 Introduction,mathieu}@caltech.edu Figure 1: Armadillo Olympics: The Armadillo model (top left) can be deformed to take various sport poses

  6. Virtual Clay: Haptics-based Deformable Solids of Arbitrary Topology

    E-Print Network [OSTI]

    McDonnell, Kevin

    Virtual Clay: Haptics-based Deformable Solids of Arbitrary Topology Kevin T. McDonnell and Hong Qin|qin}@cs.sunysb.edu Abstract. This paper presents Virtual Clay as a novel, interactive, dy- namic, haptics-based deformable solid of arbitrary topology. Our Virtual Clay methodology is a unique, powerful visual modeling paradigm

  7. Large Deformation Unbiased Diffeomorphic Nonlinear Image Registration: Theory and Implementation

    E-Print Network [OSTI]

    Soatto, Stefano

    Large Deformation Unbiased Diffeomorphic Nonlinear Image Registration: Theory and Implementation for con- structing large deformation log-unbiased image registra- tion models that generate theoretically the statistical distributions of Jacobian maps in the logarithmic space. To demonstrate the power of the proposed

  8. Seismology of plastic deformation Jero^me Weiss *, Francois Louchet

    E-Print Network [OSTI]

    Weiss, Jérôme

    Seismology of plastic deformation Je´ro^me Weiss *, Franc¸ois Louchet Laboratoire de Glaciologie et-free critical picture of dislocational plasticity that challenges the classical continuum models of plasticity rights reserved. Keywords: Acoustic methods; Dislocation dynamics; Plastic deformation; Self

  9. DNA Deformation Energy as an Indirect Recognition Mechanism in

    E-Print Network [OSTI]

    Lathrop, Richard H.

    DNA Deformation Energy as an Indirect Recognition Mechanism in Protein-DNA Interactions Kimberly A. Senear Abstract--Proteins that bind to specific locations in genomic DNA control many basic cellular. Deformation energy, which models the energy required to bend DNA from its native shape to its shape when bound

  10. HOMOGENIZATION OF A VISCOELASTIC MATRIX IN LINEAR FRICTIONAL CONTACT

    E-Print Network [OSTI]

    Panchenko, Alexander

    is assumed to be dry, and the friction law is given by a version of Coulomb's law 1991 Mathematics Subject, 18, 17, 11]. The authors of these articles study the deformation of a body coming into frictional as normal compliance. The contact conditions of Coulomb type are formulated as inequalities involving

  11. Noncommutative Deformations of Wightman Quantum Field Theories

    E-Print Network [OSTI]

    Harald Grosse; Gandalf Lechner

    2008-08-26T23:59:59.000Z

    Quantum field theories on noncommutative Minkowski space are studied in a model-independent setting by treating the noncommutativity as a deformation of quantum field theories on commutative space. Starting from an arbitrary Wightman theory, we consider special vacuum representations of its Weyl-Wigner deformed counterpart. In such representations, the effect of the noncommutativity on the basic structures of Wightman theory, in particular the covariance, locality and regularity properties of the fields, the structure of the Wightman functions, and the commutative limit, is analyzed. Despite the nonlocal structure introduced by the noncommutativity, the deformed quantum fields can still be localized in certain wedge-shaped regions, and may therefore be used to compute noncommutative corrections to two-particle S-matrix elements.

  12. Loop-deformed Poincaré algebra

    E-Print Network [OSTI]

    Jakub Mielczarek

    2013-04-08T23:59:59.000Z

    In this essay we present evidence suggesting that loop quantum gravity leads to deformation of the local Poincar\\'e algebra within the limit of high energies. This deformation is a consequence of quantum modification of effective off-shell hypersurface deformation algebra. Surprisingly, the form of deformation suggests that the signature of space-time changes from Lorentzian to Euclidean at large curvatures. We construct particular realization of the loop-deformed Poincar\\'e algebra and find that it can be related to curved momentum space, which indicates the relationship with recently introduced notion of relative locality. The presented findings open a new way of testing loop quantum gravity effects.

  13. A study of sand-asphalt mixtures: a constitutive model based on a thermomechanical framework and experimental corroboration 

    E-Print Network [OSTI]

    Ravindran, Parag

    2009-06-02T23:59:59.000Z

    . In proportion to the quantity of its usage and in acknowledgment of modeling complexity, the material has been interrogated by many researchers using a variety of mechanical tests, and a plethora of linear viscoelastic models have been developed. Most models...

  14. ${\\cal D}$-deformed harmonic oscillators

    E-Print Network [OSTI]

    F. Bagarello; F. Gargano; D. Volpe

    2014-12-30T23:59:59.000Z

    We analyze systematically several deformations arising from two-dimensional harmonic oscillators which can be described in terms of $\\cal{D}$-pseudo bosons. They all give rise to exactly solvable models, described by non self-adjoint hamiltonians whose eigenvalues and eigenvectors can be found adopting the quite general framework of the so-called $\\cal{D}$-pseudo bosons. In particular, we show that several models previously introduced in the literature perfectly fit into this scheme.

  15. Wide band Fresnel super-resolution applied to capillary break up of viscoelastic fluids

    E-Print Network [OSTI]

    Fiscina, Jorge E; Sattler, Rainer; Wagner, Christian

    2013-01-01T23:59:59.000Z

    We report a technique based on Fresnel diffraction with white illumination that permits the resolution of capillary surface patterns of less than 100 nanometers. We investigate Rayleigh Plateaux like instability on a viscoelastic capillary bridge and show that we can overcome the resolution limit of optical microscopy. The viscoelastic filaments are approximately 20 microns thick at the end of the thinning process when the instability sets in. The wavy distortions grow exponentially in time and the pattern is resolved by an image treatment that is based on an approximation of the measured rising flank of the first Fresnel peak.

  16. Wide band Fresnel super-resolution applied to capillary break up of viscoelastic fluids

    E-Print Network [OSTI]

    Jorge E. Fiscina; Pierre Fromholz; Rainer Sattler; Christian Wagner

    2013-10-05T23:59:59.000Z

    We report a technique based on Fresnel diffraction with white illumination that permits the resolution of capillary surface patterns of less than 100 nanometers. We investigate Rayleigh Plateaux like instability on a viscoelastic capillary bridge and show that we can overcome the resolution limit of optical microscopy. The viscoelastic filaments are approximately 20 microns thick at the end of the thinning process when the instability sets in. The wavy distortions grow exponentially in time and the pattern is resolved by an image treatment that is based on an approximation of the measured rising flank of the first Fresnel peak.

  17. Role of viscoelasticity and non-linear rheology in flows of complex fluids at high deformation rates

    E-Print Network [OSTI]

    Ober, Thomas J. (Thomas Joseph)

    2013-01-01T23:59:59.000Z

    We combine pressure, velocimetry and birefringence measurements to study three phenomena for which the fluid rheology plays a dominant role: 1) shear banding in micellar fluids, 2) extension-dominated flows in microfluidic ...

  18. Jordanian deformation of the open XXX-spin chain

    E-Print Network [OSTI]

    P. P. Kulish; N. Manojlovic; Z. Nagy

    2009-12-18T23:59:59.000Z

    The general solution to the reflection equation associated with the jordanian deformation of the SL(2) invariant Yang R-matrix is found. The same K-matrix is obtained by the special scaling limit of the XXZ-model with general boundary conditions. The Hamiltonian with the boundary terms is explicitly derived according to the Sklyanin formalism. We discuss the structure of the spectrum of the deformed XXX-model and its dependence on the boundary conditions.

  19. Formation of beads-on-a-string structures during breakup of viscoelastic filaments

    E-Print Network [OSTI]

    of Technology, Cambridge, MA 02139, USA e-mail: obasaran@purdue.edu Breakup of viscoelastic filaments is pervasive in both nature and technology. If a filament is formed by placing a drop of saliva between a thumb the growth of the bead and delays pinch-off, which leads to a relatively long-lived beaded structure. We also

  20. The viscoelastic behaviour of raw and anaerobic digested sludge: strong similarities with soft-glassy materials

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 The viscoelastic behaviour of raw and anaerobic digested sludge: strong similarities with soft confronted with a dramatically increasing flow of sewage sludge. To improve treatment efficiency, process reliable flow properties to simulate the process, this work is an attempt to approach sludge rheological

  1. Exceptional negative thermal expansion and viscoelastic properties of graphene oxide paper

    E-Print Network [OSTI]

    Zhong, Zhaohui

    and viscoelastic properties in graphene oxide paper. The paper was prepared from aqueous GO dispersions using]. Graphene oxide (GO), likely the most important graphene derivative, has also been prepared by oxidizing and temperature. 2. Experimental 2.1. Preparation of GO and GO paper Graphene oxide was synthesized by oxidation of

  2. A Viscoelastic Deadly Fluid in Carnivorous Pitcher Plants Laurence Gaume1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    A Viscoelastic Deadly Fluid in Carnivorous Pitcher Plants Laurence Gaume1 *, Yoel Forterre2 * 1^teau-Gombert, Marseille, France Background. The carnivorous plants of the genus Nepenthes, widely distributed in the Asian of Nepenthes pitchers as simple passive traps and is of great adaptive significance for these tropical plants

  3. A new twist on Stokes' second problem: Partial penetration of nonlinearity in sheared viscoelastic layers

    E-Print Network [OSTI]

    Forest, M. Gregory

    viscoelastic layer to an oscillating boundary, greater than the gap-loading limit of typical shear rheometers oscillatory shear driving con- ditions on the mucus layer. Very little evidence is available on the details extend our previous studies [3­5] of viscoelas- tic layers under oscillatory driving conditions

  4. Load capacity and rupture displacement in viscoelastic fiber bundles Theocharis Baxevanis1,

    E-Print Network [OSTI]

    Katsaounis, Theodoros D.

    for this critical load is given. For stress levels below the critical value, the system suffers only partial failureLoad capacity and rupture displacement in viscoelastic fiber bundles Theocharis Baxevanis1 loading, assuming global load sharing GLS for the redistribution of load following fiber failure. We

  5. VISCOELASTIC BEHAVIOR OF POLYMER-THICKENED WATER-IN-OIL EMULSIONS

    E-Print Network [OSTI]

    Natelson, Douglas

    behavior of emulsions of water dispersed in a lubricant oil base and stabilized with a nonionic surfactantVISCOELASTIC BEHAVIOR OF POLYMER-THICKENED WATER-IN- OIL EMULSIONS MONTESI PE�A HIRASAKI PASQUALI concentration, emulsions with and without polyisobutylene (PIB, MW = 2.1 ± 0.2 x 106 Da) added to the oil phase

  6. Elastic and Viscoelastic Properties of Non-bulk Polymer Interphases in Nanotube-reinforced Polymers

    E-Print Network [OSTI]

    Fisher, Frank

    Elastic and Viscoelastic Properties of Non-bulk Polymer Interphases in Nanotube-reinforced Polymers polymer composite materials with outstanding mechanical, electrical, and thermal properties. A hurdle to nanoscale interactions between the embedded NTs and adjacent polymer chains. This interphase region

  7. Peristaltic pumping of a viscoelastic fluid at high occlusion ratios and large Weissenberg numbers

    E-Print Network [OSTI]

    Bigelow, Stephen

    Peristaltic pumping of a viscoelastic fluid at high occlusion ratios and large Weissenberg numbers pumping is a mechanism for transporting fluid or immersed par- ticles in a channel by waves of contraction- vestigate numerically the peristaltic pumping of an incompressible viscoelas- tic fluid using the simple

  8. Peristaltic pumping and irreversibility of a Stokesian viscoelastic fluid Joseph Teran,1

    E-Print Network [OSTI]

    Shelley, Michael

    Peristaltic pumping and irreversibility of a Stokesian viscoelastic fluid Joseph Teran,1 Lisa Fauci, USA Received 28 January 2008; accepted 1 July 2008; published online 28 July 2008 Peristaltic pumping in the esophagus, intestine, oviduct, and ureter. While peristaltic pumping of a Newtonian fluid is well understood

  9. Overall response of viscoelastic composites and polycrystals: exact asymptotic relations and

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    to a creep test (see Subsection 2.2 and Figure 1). For simplicity the present study will be focused emphasis on their transient response. First, two new asymptotic relations for the overall creep function: linear viscoelasticity, homogenization, effective creep function, particulate composites, polycrystals

  10. 3.22 Mechanical Properties of Materials Test 2: Viscoelasticity and Plasticity

    E-Print Network [OSTI]

    Goldwasser, Shafi

    are allowed to bring one 8.5" x 11" sheet into the test. 1. The creep behaviour of polyethylene is given3.22 Mechanical Properties of Materials Test 2: Viscoelasticity and Plasticity April 25, 2002 You by the creep compliance data in the table below. Creep compliance of Polyethylene t (hours) J(t) (psi-1) 0 0

  11. Viscoelastic Behavior of Poly(ether imide) Incorporated with Multiwalled Carbon Nanotubes

    E-Print Network [OSTI]

    Fisher, Frank

    plastic, and suitable for use in many demanding applications because of its relatively high strength, high, and thermal properties of engineering plastics, including poly(ether imide) (PEI), with various nanoin; viscoelastic properties INTRODUCTION The demand for lightweight materials with high strength and thermal

  12. Normal Stresses and Interface Displacement: Influence of Viscoelasticity on Enhanced Oil

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Normal Stresses and Interface Displacement: Influence of Viscoelasticity on Enhanced Oil Recovery assistée -- Une des méthodes de récupération assistée du pétrole (EOR - Enhanced Oil Recovery) consiste à Recovery Efficiency -- One of chemical Enhanced Oil Recovery (EOR) methods consists in injecting aqueous

  13. Cyclic performance of viscoelastic dielectric elastomers with solid hydrogel Yuanyuan Bai,1

    E-Print Network [OSTI]

    Suo, Zhigang

    of manufacturing or fabrication by 3D printing, silent operation, and capability of large deformation.1

  14. VoxMorph: 3-Scale Freeform Deformation of Large Voxel Grids Noura Faraj, Jean-Marc Thiery and Tamy Boubekeur

    E-Print Network [OSTI]

    Boubekeur, Tamy

    for high resolution voxel grids. Our system exploits cages for high-level deformation control. We tackle embedding the voxel model. This cage acts as the unique deformation control interface and is cla the interactive session, resulting in a high resolution voxel grid containing the deformed model. We tested our

  15. Deformation Expression for Elements of Algebra

    E-Print Network [OSTI]

    H. Omori; Y. Maeda; N. Miyazaki; A. Yoshioka

    2011-04-09T23:59:59.000Z

    The purpose of this paper is to give a notion of deformation of expressions for elements of algebra. Deformation quantization (cf.[BF]) deforms the commutative world to a non-commutative world. However, this involves deformation of expression of elements of algebras even from a commutative world to another commutative world. This is indeed a deformation of expressions for elements of algebra.

  16. Morita Equivalence in Deformation Quantization Henrique Bursztyn

    E-Print Network [OSTI]

    Bursztyn, Henrique

    Morita Equivalence in Deformation Quantization by Henrique Bursztyn Engineer (Universidade Federal at Berkeley Spring 2001 #12;Morita Equivalence in Deformation Quantization Copyright 2001 by Henrique Bursztyn #12;1 Abstract Morita Equivalence in Deformation Quantization by Henrique Bursztyn Doctor

  17. A unified method for the analysis of nonlinear viscoelasticity and fatigue cracking of asphalt mixtures using the dynamic mechanical analyzer

    E-Print Network [OSTI]

    Castelo Branco, Veronica Teixeira Franco

    2009-05-15T23:59:59.000Z

    A UNIFIED METHOD FOR THE ANALYSIS OF NONLINEAR VISCOELASTICITY AND FATIGUE CRACKING OF ASPHALT MIXTURES USING THE DYNAMIC MECHANICAL ANALYZER A Dissertation by VERONICA TEIXEIRA FRANCO CASTELO BRANCO Submitted to the Office... VISCOELASTICITY AND FATIGUE CRACKING OF ASPHALT MIXTURES USING THE DYNAMIC MECHANICAL ANALYZER A Dissertation by VERONICA TEIXEIRA FRANCO CASTELO BRANCO Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...

  18. The effect of confinement on the deformation of microfluidic drops

    E-Print Network [OSTI]

    Ulloa, Camilo; Cordero, María Luisa

    2013-01-01T23:59:59.000Z

    We study the deformation of drops squeezed between the floor and ceiling of a microchannel and subjected to a hyperbolic flow. We observe that the maximum deformation of drops depends on both the drop size and the rate of strain of the external flow and can be described with power laws with exponents 2.59 +/- 0.28 and 0.94 +/- 0.04 respectively. We develop a theoretical model to describe the deformation of squeezed drops based on the Darcy approximation for shallow geometries and the use of complex potentials. The model describes the steady-state deformation of the drops as a function of a non-dimensional parameter Ca d^2, where Ca is the capillary number (proportional to the strain rate and the drop size) and d is a confinement parameter equal to the drop size divided by the channel height. For small deformations, the theoretical model predicts a linear relationship between the deformation of drops and this parameter, in good agreement with the experimental observations.

  19. Triaxially deformed relativistic point-coupling model for $\\Lambda$ hypernuclei: a quantitative analysis of hyperon impurity effect on nuclear collective properties

    E-Print Network [OSTI]

    Xue, W X; Hagino, K; Li, Z P; Mei, H; Tanimura, Y

    2014-01-01T23:59:59.000Z

    The impurity effect of hyperon on atomic nuclei has received a renewed interest in nuclear physics since the first experimental observation of appreciable reduction of $E2$ transition strength in low-lying states of hypernucleus $^{7}_\\Lambda$Li. Many more data on low-lying states of $\\Lambda$ hypernuclei will be measured soon for $sd$-shell nuclei, providing good opportunities to study the $\\Lambda$ impurity effect on nuclear low-energy excitations. We carry out a quantitative analysis of $\\Lambda$ hyperon impurity effect on the low-lying states of $sd$-shell nuclei at the beyond-mean-field level based on a relativistic point-coupling energy density functional (EDF), considering that the $\\Lambda$ hyperon is injected into the lowest positive-parity ($\\Lambda_s$) and negative-parity ($\\Lambda_p$) states. We adopt a triaxially deformed relativistic mean-field (RMF) approach for hypernuclei and calculate the $\\Lambda$ binding energies of hypernuclei as well as the potential energy surfaces (PESs) in $(\\beta, \\g...

  20. The viscoelastic properties of chromatin and the nucleoplasm revealed by scale-dependent protein mobility

    E-Print Network [OSTI]

    Fabian Erdel; Michael Baum; Karsten Rippe

    2014-09-23T23:59:59.000Z

    The eukaryotic cell nucleus harbors the DNA genome that is organized in a dynamic chromatin network and embedded in a viscous crowded fluid. This environment directly affects enzymatic reactions and target search processes that access the DNA sequence information. However, its physical properties as a reaction medium are poorly understood. Here, we exploit mobility measurements of differently sized inert green fluorescent tracer proteins to characterize the viscoelastic properties of the nuclear interior of a living human cell. We find that it resembles a viscous fluid on small and large scales, but appears viscoelastic on intermediate scales that change with protein size. Our results are consistent with simulations of diffusion through polymers and suggest that chromatin forms a random obstacle network rather than a self-similar structure with fixed fractal dimension. By calculating how long molecules remember their previous position in dependence on their size, we evaluate how the nuclear environment affects search processes of chromatin targets.

  1. S-matrix for strings on $\\eta$-deformed AdS5 x S5

    E-Print Network [OSTI]

    Arutyunov, Gleb; Frolov, Sergey

    2014-01-01T23:59:59.000Z

    We determine the bosonic part of the superstring sigma model Lagrangian on $\\eta$-deformed AdS5 x S5, and use it to compute the perturbative world-sheet scattering matrix of bosonic particles of the model. We then compare it with the large string tension limit of the q-deformed S-matrix and find exact agreement.

  2. S-matrix for strings on $?$-deformed AdS5 x S5

    E-Print Network [OSTI]

    Gleb Arutyunov; Riccardo Borsato; Sergey Frolov

    2014-04-07T23:59:59.000Z

    We determine the bosonic part of the superstring sigma model Lagrangian on $\\eta$-deformed AdS5 x S5, and use it to compute the perturbative world-sheet scattering matrix of bosonic particles of the model. We then compare it with the large string tension limit of the q-deformed S-matrix and find exact agreement.

  3. Viscoelastic-stiffness tensor of anisotropic media from oscillatory ...

    E-Print Network [OSTI]

    Juan E. Santos

    2010-12-27T23:59:59.000Z

    Nov 19, 2010 ... Many geological systems can be modeled as effective trans- versely isotropic and ...... data for characterization purposes. References.

  4. Soft-sediment and hard-rock deformation in the Chinle Formation, Northeastern Arizona

    E-Print Network [OSTI]

    Scheevel, Jay Roger

    1983-01-01T23:59:59.000Z

    as to deformation-type are: (1) chevron-folds (1 to 300 m wavelengths), (2) decollement or truncated surfaces, (3) plunging folds, (4) slickensided shear- surfaces in claystones. Microscopic observation of the deformed sandstones reveals that the order.... Microscopic Study. Model Study. 1 1 2 3 10 10 11 11 13 13 14 16 17 17 17 18 FIELD OBSERVATIONS 19 Introduction Soft-sediment Deformation St. Johns, Arizona General description Folds and Decollement Soft-sediment Small-faults Subsidiary...

  5. 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]

    Srivastava, Vikas

    2010-01-01T23:59:59.000Z

    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 ...

  6. Analysis on q-deformed quantum spaces

    E-Print Network [OSTI]

    Hartmut Wachter

    2006-04-13T23:59:59.000Z

    A q-deformed version of classical analysis is given to quantum spaces of physical importance, i.e. Manin plane, q-deformed Euclidean space in three or four dimensions, and q-deformed Minkowski space. The subject is presented in a rather complete and selfcontained way. All relevant notions are introduced and explained in detail. The different possibilities to realize the objects of q-deformed analysis are discussed and their elementary properties are studied. In this manner attention is focused on star products, q-deformed tensor products, q-deformed translations, q-deformed partial derivatives, dual pairings, q-deformed exponentials, and q-deformed integration. The main concern of this work is to show that these objects fit together in a consistent framework, which is suitable to formulate physical theories on quantum spaces.

  7. Modeling and Algorithmic Approaches to Constitutively-Complex, Micro-structured Fluids

    SciTech Connect (OSTI)

    Forest, Mark Gregory [University of North Carolina at Chapel Hill] [University of North Carolina at Chapel Hill

    2014-05-06T23:59:59.000Z

    The team for this Project made significant progress on modeling and algorithmic approaches to hydrodynamics of fluids with complex microstructure. Our advances are broken down into modeling and algorithmic approaches. In experiments a driven magnetic bead in a complex fluid accelerates out of the Stokes regime and settles into another apparent linear response regime. The modeling explains the take-off as a deformation of entanglements, and the longtime behavior is a nonlinear, far-from-equilibrium property. Furthermore, the model has predictive value, as we can tune microstructural properties relative to the magnetic force applied to the bead to exhibit all possible behaviors. Wave-theoretic probes of complex fluids have been extended in two significant directions, to small volumes and the nonlinear regime. Heterogeneous stress and strain features that lie beyond experimental capability were studied. It was shown that nonlinear penetration of boundary stress in confined viscoelastic fluids is not monotone, indicating the possibility of interlacing layers of linear and nonlinear behavior, and thus layers of variable viscosity. Models, algorithms, and codes were developed and simulations performed leading to phase diagrams of nanorod dispersion hydrodynamics in parallel shear cells and confined cavities representative of film and membrane processing conditions. Hydrodynamic codes for polymeric fluids are extended to include coupling between microscopic and macroscopic models, and to the strongly nonlinear regime.

  8. Realistic Haptic Rendering of Interacting Deformable Objects in Virtual Environments

    E-Print Network [OSTI]

    Duriez, Christian; Kheddar, Abderrahmane; Andriot, Claude

    2008-01-01T23:59:59.000Z

    A new computer haptics algorithm to be used in general interactive manipulations of deformable virtual objects is presented. In multimodal interactive simulations, haptic feedback computation often comes from contact forces. Subsequently, the fidelity of haptic rendering depends significantly on contact space modeling. Contact and friction laws between deformable models are often simplified in up to date methods. They do not allow a "realistic" rendering of the subtleties of contact space physical phenomena (such as slip and stick effects due to friction or mechanical coupling between contacts). In this paper, we use Signorini's contact law and Coulomb's friction law as a computer haptics basis. Real-time performance is made possible thanks to a linearization of the behavior in the contact space, formulated as the so-called Delassus operator, and iteratively solved by a Gauss-Seidel type algorithm. Dynamic deformation uses corotational global formulation to obtain the Delassus operator in which the mass and s...

  9. TO APPEAR IN THE PROCEEDINGS OF THE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION (ICRA), 2011. Modeling and Perception of Deformable One-Dimensional Objects

    E-Print Network [OSTI]

    Abbeel, Pieter

    the simulation, perception, and manipulation of such objects. An important application of these tasks lies that are highly dependent on material properties. This paper proposes an approach for fitting simulation models-rigid objects like thread, rope, hair, and plants in real world settings is a challenging task. These objects

  10. Modeling and Perception of Deformable One-Dimensional Objects Shervin Javdani, Sameep Tandon, Jie Tang, James F. O'Brien, Pieter Abbeel

    E-Print Network [OSTI]

    O'Brien, James F.

    the simulation, perception, and manipulation of such objects. An important application of these tasks lies that are highly dependent on material properties. This paper proposes an approach for fitting simulation models-rigid objects like thread, rope, hair, and plants in real world settings is a challenging task. These objects

  11. Fluid-driven deformation of a soft granular material

    E-Print Network [OSTI]

    Christopher W. MacMinn; Eric R. Dufresne; John S. Wettlaufer

    2015-02-24T23:59:59.000Z

    Compressing a porous, fluid-filled material will drive the interstitial fluid out of the pore space, as when squeezing water out of a kitchen sponge. Inversely, injecting fluid into a porous material can deform the solid structure, as when fracturing a shale for natural gas recovery. These poromechanical interactions play an important role in geological and biological systems across a wide range of scales, from the propagation of magma through the Earth's mantle to the transport of fluid through living cells and tissues. The theory of poroelasticity has been largely successful in modeling poromechanical behavior in relatively simple systems, but this continuum theory is fundamentally limited by our understanding of the pore-scale interactions between the fluid and the solid, and these problems are notoriously difficult to study in a laboratory setting. Here, we present a high-resolution measurement of injection-driven poromechanical deformation in a system with granular microsctructure: We inject fluid into a dense, confined monolayer of soft particles and use particle tracking to reveal the dynamics of the multi-scale deformation field. We find that a continuum model based on poroelasticity theory captures certain macroscopic features of the deformation, but the particle-scale deformation field exhibits dramatic departures from smooth, continuum behavior. We observe particle-scale rearrangement and hysteresis, as well as petal-like mesoscale structures that are connected to material failure through spiral shear banding.

  12. WAVE-SOLID INTERACTIONS IN SHOCK INDUCED DEFORMATION PROCESSES Paper #1003

    E-Print Network [OSTI]

    Yao, Y. Lawrence

    pressure created by the shock wave is above the dynamic yield stress (Hugonoit Elastic Limit, HEL) of metalWAVE-SOLID INTERACTIONS IN SHOCK INDUCED DEFORMATION PROCESSES Paper #1003 Yajun Fan, Youneng Wang 10027, USA Abstract A model was developed for material deformation processes induced by laser generated

  13. Low fault friction in Iran implies localized deformation for the ArabiaEurasia collision zone

    E-Print Network [OSTI]

    Vernant, Philippe

    Low fault friction in Iran implies localized deformation for the Arabia­Eurasia collision zone P velocity field of the present-day deformation in Iran is modeled using a 3-dimensional (3D) finite element of the kinematics in Iran, but the complex velocity field of the surrounding South Caspian basin cannot be fitted

  14. Deforming nanocrystalline nickel at ultrahigh strain rates Y. M. Wang,a

    E-Print Network [OSTI]

    Meyers, Marc A.

    Deforming nanocrystalline nickel at ultrahigh strain rates Y. M. Wang,a E. M. Bringa, J. M. Mc of this letter is to investigate these deformation mechanisms using a model material, nanocrystalline nickel Goodfellow Inc.; and 2 we also electrodeposited Ni samples at several other grain sizes, 30­100 nm.11

  15. Vane shear determination of the visco-elastic shear modulus of submarine sediments 

    E-Print Network [OSTI]

    Stevenson, Herbert Scott

    1973-01-01T23:59:59.000Z

    viscoelastic theory and torque versus rotation data from vane shear tests. The modu- lus, G(t), is described by the power law: G(t) = G, t where t is time, and G, and n are constants. G, and n are deter- mined from vane tests on deep sediment core samples.... G, is rota- tion angle dependent. The validity of the procedure is supported by predict1ons of in situ vane test torque versus rotation curves wh1ch agree favorably with data obtained using an in s1tu vane device. G, correlates with maximum vane...

  16. A non-linear elastic constitutive framework for replicating plastic deformation in solids.

    SciTech Connect (OSTI)

    Roberts, Scott Alan; Schunk, Peter Randall

    2014-02-01T23:59:59.000Z

    Ductile metals and other materials typically deform plastically under large applied loads; a behavior most often modeled using plastic deformation constitutive models. However, it is possible to capture some of the key behaviors of plastic deformation using only the framework for nonlinear elastic mechanics. In this paper, we develop a phenomenological, hysteretic, nonlinear elastic constitutive model that captures many of the features expected of a plastic deformation model. This model is based on calculating a secant modulus directly from a material's stress-strain curve. Scalar stress and strain values are obtained in three dimensions by using the von Mises invariants. Hysteresis is incorporated by tracking an additional history variable and assuming an elastic unloading response. This model is demonstrated in both single- and multi-element simulations under varying strain conditions.

  17. Four-dimensional deformed special relativity from group field theories

    SciTech Connect (OSTI)

    Girelli, Florian [SISSA, Via Beirut 2-4, 34014 Trieste, Italy and INFN, Sezione di Trieste (Italy); School of Physics, University of Sydney, Sydney, New South Wales 2006 (Australia); Livine, Etera R. [Laboratoire de Physique, ENS Lyon, CNRS UMR 5672, 46 Allee d'Italie, 69007 Lyon (France); Oriti, Daniele [Perimeter Institute for Theoretical Physics, 31 Caroline St, Waterloo, Ontario N2L 2Y5 (Canada); Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, Utrecht 3584 TD (Netherlands); Albert Einstein Institute, Am Muehlenberg 4, Golm (Germany)

    2010-01-15T23:59:59.000Z

    We derive a scalar field theory of the deformed special relativity type, living on noncommutative {kappa}-Minkowski space-time and with a {kappa}-deformed Poincare symmetry, from the SO(4,1) group field theory defining the transition amplitudes for topological BF theory in 4 space-time dimensions. This is done at a nonperturbative level of the spin foam formalism working directly with the group field theory (GFT). We show that matter fields emerge from the fundamental model as perturbations around a specific phase of the GFT, corresponding to a solution of the fundamental equations of motion, and that the noncommutative field theory governs their effective dynamics.

  18. Viscoelastic modes in a strongly coupled, cold, magnetized dusty plasma

    SciTech Connect (OSTI)

    Banerjee, Debabrata; Mylavarapu, Janaki Sita; Chakrabarti, Nikhil [Saha Institute of Nuclear Physics, I/AF Bidhannagar, Calcutta 700 064 (India)

    2010-11-15T23:59:59.000Z

    A generalized hydrodynamical model has been used to study the low frequency modes in a strongly coupled, cold, magnetized dusty plasma. Such plasmas exhibit elastic properties due to the strong correlations among dust particles and the tensile stresses imparted by the magnetic field. It has been shown that longitudinal compressional Alfven modes and elasticity modified transverse shear mode exist in such a medium. The features of these collective modes are established and discussed.

  19. Quantum mechanical effects from deformation theory

    SciTech Connect (OSTI)

    Much, A. [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig, Germany and Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)] [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig, Germany and Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)

    2014-02-15T23:59:59.000Z

    We consider deformations of quantum mechanical operators by using the novel construction tool of warped convolutions. The deformation enables us to obtain several quantum mechanical effects where electromagnetic and gravitomagnetic fields play a role. Furthermore, a quantum plane can be defined by using the deformation techniques. This in turn gives an experimentally verifiable effect.

  20. CubeSat deformable mirror demonstration

    E-Print Network [OSTI]

    Cahoy, Kerri

    The goal of the CubeSat Deformable Mirror Demonstration (DeMi) is to characterize the performance of a small deformable mirror over a year in low-Earth orbit. Small form factor deformable mirrors are a key technology needed ...

  1. Strain Heterogeneity and Damage Nucleation at Grain Boundaries during Monotonic Deformation in Commercial Purity Titanium

    SciTech Connect (OSTI)

    Bieler, T. R. [Michigan State University, East Lansing; Crimp, M. A. [Michigan State University, East Lansing; Yang, Y. [Michigan State University, East Lansing; Eisenlohr, P. [Max-Planck-Institut fur Eisenforschung, Germany; Mason, D. E. [Albion College; Liu, W. [Argonne National Laboratory (ANL); Ice, Gene E [ORNL

    2009-01-01T23:59:59.000Z

    Heteroeneous strain was analyzed in polycrystalline, commercial-purity titanium using many experimental techniques that provide information about microstructure, dislocation arrangement, grain orientation, orientation gradients, surface topography, and local strain gradients. The recrystallized microstructure with 50-200 ?m grains was extensively characterized before and after deformation using 4-point bending to strains between 2% and 15%. Extremely heterogeneous deformation occurred along some grain boundaries, leading to orientation gradients exceeding 10{sup o} over 10-20 {micro}m. Patches of highly characterized microstructure were modeled using crystal plasticity finite element (CPFE) analysis to simulate the deformation to evaluate the ability of the CPFE model to capture local deformation processes. Damage nucleation events were identified that are associated with twin interactions with grain boundaries. Progress toward identifying fracture initiation criteria based upon slip and twin interactions with grain boundaries is illustrated with related CPFE simulations of deformation in a TiAl alloy.

  2. Deformation mechanisms of experimentally deformed Salina Basin bedded salt

    SciTech Connect (OSTI)

    Hansen, F.D.

    1985-01-01T23:59:59.000Z

    Petrofabrics of deformed salt from the Cleveland area within the Salina Basin are presented. Quasi-static compression at room temperature and 1 MPa confining pressure is dominated by fracture. Incipient failure is evidenced by wide zones of coalesced fractures at an axial strain of 5%. Strain hardening, evidenced by photoelastic effects, abounds under these conditions. At 5 MPa far fewer fractures are found at axial strains of 13%. Photoelastic effects are appreciably diminished at 5 MPa, which must mean more homogeneous ductile flow ensues, perhaps owing to activation of many dislocation mills. Clearly, the brittle-to-ductile transition requires additional petrographic work for documentation. Because the dominant mechanism is very pressure sensitive at relative low mean stresses, it appears necessary to include confining pressure in the deformation mechanism map. Creep at 15 MPa and temperatures >100/sup 0/C is dominated by thermally activated diffusion. Fracture and photoelastic effects are almost totally suppressed relative to quasi-static experiments at lower confining pressure and temperature. The mechanism of climb into stable polygons is fully documented by etch pit studies in samples that are deformed well into steady state. Creep properties of Cleveland and Avery Island salt are very similar under conditions of elevated temperature and intermediate stresses. As temperature is reduced the predicted flow stress of Cleveland becomes greater than that of Avery Island. However, extrapolation of either flow law to low temperature is not justified because the governing mechanisms change from climb to fracture and glide.

  3. On the postglacial isostatic adjustment of the British Isles and the shallow viscoelastic structure of the Earth

    E-Print Network [OSTI]

    Peltier, W. Richard

    of the Earth W. R. Peltier,1 I. Shennan,2 R. Drummond1 and B. Horton2 1 Department of Physics, University viscoelastic theory of the glacial isostatic adjustment (GIA) process, most recently reviewed in Peltier (1998a on the inverse problem for mantle viscosity (see the papers by Peltier 1998b and Wieczerkowski et al. 1999

  4. Elastic and viscoelastic effects in rubber/air acoustic band gap structures: A theoretical and experimental study

    E-Print Network [OSTI]

    Deymier, Pierre

    Elastic and viscoelastic effects in rubber/air acoustic band gap structures: A theoretical rubber/air phononic crystal structures is investigated theoretically and experimentally. We introduce in a solid rubber matrix, as well as an array of rubber cylinders in an air matrix, are shown to behave

  5. $?$-Deformed Statistics and Classical Fourmomentum Addition Law

    E-Print Network [OSTI]

    M. Daszkiewicz; J. Lukierski; M. Woronowicz

    2008-02-05T23:59:59.000Z

    We consider $\\kappa$-deformed relativistic symmetries described algebraically by modified Majid-Ruegg bicrossproduct basis and investigate the quantization of field oscillators for the $\\kappa$-deformed free scalar fields on $\\kappa$-Minkowski space. By modification of standard multiplication rule, we postulate the $\\kappa$-deformed algebra of bosonic creation and annihilation operators. Our algebra permits to define the n-particle states with classical addition law for the fourmomenta in a way which is not in contradiction with the nonsymmetric quantum fourmomentum coproduct. We introduce $\\kappa$-deformed Fock space generated by our $\\kappa$-deformed oscillators which satisfy the standard algebraic relations with modified $\\kappa$-multiplication rule. We show that such a $\\kappa$-deformed bosonic Fock space is endowed with the conventional bosonic symmetry properties. Finally we discuss the role of $\\kappa$-deformed algebra of oscillators in field-theoretic noncommutative framework.

  6. An Integrable Deformation of the AdS5 x S5 Superstring

    E-Print Network [OSTI]

    Timothy J. Hollowood; J. Luis Miramontes; David M. Schmidtt

    2014-09-24T23:59:59.000Z

    The S-matrix on the world-sheet theory of the string in AdS5 x S5 has previously been shown to admit a deformation where the symmetry algebra is replaced by the associated quantum group. The case where q is real has been identified as a particular deformation of the Green-Schwarz sigma model. An interpretation of the case with q a root of unity has, until now, been lacking. We show that the Green-Schwarz sigma model admits a discrete deformation which can be viewed as a rather simple deformation of the F/F_V gauged WZW model, where F=PSU(2,2|4). The deformation parameter q is then a k-th root of unity where k is the level. The deformed theory has the same equations-of-motion as the Green-Schwarz sigma model but has a different symplectic structure. We show that the resulting theory is integrable and has just the right amount of kappa-symmetries that appear as a remnant of the fermionic part of the original gauge symmetry. This points to the existence of a fully consistent deformed string background.

  7. An Integrable Deformation of the AdS5 x S5 Superstring

    E-Print Network [OSTI]

    Hollowood, Timothy J; Schmidtt, David

    2014-01-01T23:59:59.000Z

    The S-matrix on the world-sheet theory of the string in AdS5 x S5 has previously been shown to admit a deformation where the symmetry algebra is replaced by the associated quantum group. The case where q is real has been identified as a particular deformation of the Green-Schwarz sigma model. An interpretation of the case with q a root of unity has, until now, been lacking. We show that the Green-Schwarz sigma model admits a discrete deformation which can be viewed as a rather simple deformation of the F/F gauged WZW model, where F=PSU(2,2|4). The deformation parameter q is then a k-th root of unity where k is the level. The deformed theory has the same equations-of-motion as the Green-Schwarz sigma model but has a different symplectic structure. We show that the resulting theory is integrable and has just the right amount of kappa-symmetries that appear as a remnant of the fermionic part of the original gauge symmetry. This points to the existence of a fully consistent deformed string background.

  8. Volume 0 (1981), Number 0 pp. 17 COMPUTER GRAPHICS forum Resampling Strategies for Deforming MLS Surfaces

    E-Print Network [OSTI]

    Buscaglia, Gustavo C.

    Volume 0 (1981), Number 0 pp. 1­7 COMPUTER GRAPHICS forum Resampling Strategies for Deforming MLS Graphics]: Computational Geometry and Object Modeling G.1.2 [Numerical Analysis]: Approximation G.2

  9. Integrable $?$-deformations: Squashing Coset CFTs and $AdS_5\\times S^5$

    E-Print Network [OSTI]

    Saskia Demulder; Konstantinos Sfetsos; Daniel C. Thompson

    2015-04-10T23:59:59.000Z

    We examine integrable $\\lambda$-deformations of $SO(n+1)/SO(n)$ coset CFTs and their analytic continuations. We provide an interpretation of the deformation as a squashing of the corresponding coset $\\sigma$-model's target space. We realise the $\\lambda$-deformation for $n=5$ case as a solution to supergravity supported by non-vanishing five-form and dilaton. This interpolates between the coset CFT $SO(4,2)/SO(4,1)\\times SO(6)/SO(5)$ constructed as a gauged WZW model and the non-Abelian T-dual of the $AdS_5\\times S^5$ spacetime.

  10. Physical and Statistical Models in Deformation Geodesy

    E-Print Network [OSTI]

    Lipovsky, Brad

    2011-01-01T23:59:59.000Z

    dvpb dvnw dvne dvlw dvls dvle dssc dsme dshs dhlg desc dam3dvpb dvnw dvne dvlw dvls dvle dssc dsme dshs dhlg desc dam3dvpb dvnw dvne dvlw dvls dvle dssc dsme dshs dhlg desc dam3

  11. Quantum limits to estimation of photon deformation

    E-Print Network [OSTI]

    Giovanni De Cillis; Matteo G. A. Paris

    2014-07-08T23:59:59.000Z

    We address potential deviations of radiation field from the bosonic behaviour and employ local quantum estimation theory to evaluate the ultimate bounds to precision in the estimation of these deviations using quantum-limited measurements on optical signals. We consider different classes of boson deformation and found that intensity measurement on coherent or thermal states would be suitable for their detection making, at least in principle, tests of boson deformation feasible with current quantum optical technology. On the other hand, we found that the quantum signal-to-noise ratio (QSNR) is vanishing with the deformation itself for all the considered classes of deformations and probe signals, thus making any estimation procedure of photon deformation inherently inefficient. A partial way out is provided by the polynomial dependence of the QSNR on the average number of photon, which suggests that, in principle, it would be possible to detect deformation by intensity measurements on high-energy thermal states.

  12. Studies of the viscoelastic properties of water confined between surfaces of specified chemical nature.

    SciTech Connect (OSTI)

    Houston, Jack E.; Grest, Gary Stephen; Moore, Nathan W.; Feibelman, Peter J.

    2010-09-01T23:59:59.000Z

    This report summarizes the work completed under the Laboratory Directed Research and Development (LDRD) project 10-0973 of the same title. Understanding the molecular origin of the no-slip boundary condition remains vitally important for understanding molecular transport in biological, environmental and energy-related processes, with broad technological implications. Moreover, the viscoelastic properties of fluids in nanoconfinement or near surfaces are not well-understood. We have critically reviewed progress in this area, evaluated key experimental and theoretical methods, and made unique and important discoveries addressing these and related scientific questions. Thematically, the discoveries include insight into the orientation of water molecules on metal surfaces, the premelting of ice, the nucleation of water and alcohol vapors between surface asperities and the lubricity of these molecules when confined inside nanopores, the influence of water nucleation on adhesion to salts and silicates, and the growth and superplasticity of NaCl nanowires.

  13. A Viscoelastic-Viscoplastic Analysis of Fiber Reinforced Polymer Composites Undergoing Mechanical Loading and Temperature Changes

    E-Print Network [OSTI]

    Jeon, Jaehyeuk

    2013-08-09T23:59:59.000Z

    of thermal stresses, due to the mismatches in the coefficient of thermal expansions of the fibers and polymeric matrix, and stress concentrations/discontinuities near the fiber and matrix interfaces on the overall thermo-mechanical deformation of FRP...

  14. 2012 ROCK DEFORMATION: FEEDBACK PROCESSES IN ROCK DEFORMATION GORDON RESEARCH CONFERENCE, AUGUST 19-24, 2012

    SciTech Connect (OSTI)

    Kelemen, Peter

    2012-08-24T23:59:59.000Z

    Topics covered include: Failure At High Confining Pressure; Fluid-assisted Slip, Earthquakes & Fracture; Reaction-driven Cracking; Fluid Transport, Deformation And Reaction; Localized Fluid Transport And Deformation; Earthquake Mechanisms; Subduction Zone Dynamics And Crustal Growth.

  15. Deformation-Twin-Induced Grain Boundary Failure

    SciTech Connect (OSTI)

    Yongfeng Zhang; Paul C. MIllett; Michael Tonks; Bulent Biner

    2012-01-01T23:59:59.000Z

    This work presents a mechanism of deformation-twin-induced grain boundary failure, and demonstrates the mechanism using molecular dynamics simulations. Deformation twinning is observed as the dominant mechanism during tensile deformation of columnar nanocrystalline body-centered cubic Mo. As a twin approaches a grain boundary, local stress concentration develops due to the incompatible plastic deformations in the two neighboring grains. The magnitude of the stress concentration increases as the twin widens, leading to grain boundary cracking by nucleation and coalescence of microcracks/voids.

  16. Influence of shockwave obliquity on deformation twin formation in Ta

    SciTech Connect (OSTI)

    Gray, George T., III [Los Alamos National Laboratory; Livescu, V [Los Alamos National Laboratory; Cerreta, E K [Los Alamos National Laboratory; Mason, T A [Los Alamos National Laboratory; Maudlin, P J [RETIRED; Bingert, J F [Los Alamos National Laboratory

    2009-02-18T23:59:59.000Z

    Energetic loading subjects a material to a 'Taylor wave' (triangular wave) loading profile that experiences an evolving balance of hydrostatic (spherical) and deviatoric stresses. While much has been learned over the past five decades concerning the propensity of deformation twinning in samples shockloaded using 'square-topped' profiles as a function of peak stress, achieved most commonly via flyer plate loading, less is known concerning twinning propensity during non-I-dimensional sweeping detonation wave loading. Systematic small-scale energetically-driven shock loading experiments were conducted on Ta samples shock loaded with PEFN that was edge detonated. Deformation twinning was quantified in post-mortem samples as a function of detonation geometry and radial position. In the edge detonated loading geometry examined in this paper, the average volume fraction of deformation twins was observed to drastically increase with increasing shock obliquity. The results of this study are discussed in light of the formation mechanisms of deformation twins, previous literature studies of twinning in shocked materials, and modeling of the effects of shock obliquity on the evolution of the stress tensor during shock loading.

  17. Nuclear dynamical deformation induced hetero- and euchromatin positioning

    E-Print Network [OSTI]

    Akinori Awazu

    2015-06-12T23:59:59.000Z

    The contributions of active deformation dynamics in cell nuclei to the intra-nuclear positioning of hetero- and euchromatin are investigated. We analyzed the behaviors of model chains containing two types of regions, one with high and the other with low mobility, confined in a pulsating container. Here, the regions with high and low mobility represent eu- and heterochromatic regions, respectively, and the pulsating container simulates a nucleus exhibiting dynamic deformations. The Brownian dynamics simulations of this model show that the positioning of low mobility regions transition from sites near the periphery to the central region of the container if the affinity between low mobility regions and the container periphery disappears. Here, the former and latter positioning are similar to the "conventional" and "inverted" chromatin positioning observed in nuclei of normal differentiated cells and cells lacking Lamin-related proteins like mouse rod photoreceptor cell.

  18. Finite-element analysis of the deformation of thin Mylar films due to measurement forces.

    SciTech Connect (OSTI)

    Baker, Michael Sean; Robinson, Alex Lockwood; Tran, Hy D.

    2012-01-01T23:59:59.000Z

    Significant deformation of thin films occurs when measuring thickness by mechanical means. This source of measurement error can lead to underestimating film thickness if proper corrections are not made. Analytical solutions exist for Hertzian contact deformation, but these solutions assume relatively large geometries. If the film being measured is thin, the analytical Hertzian assumptions are not appropriate. ANSYS is used to model the contact deformation of a 48 gauge Mylar film under bearing load, supported by a stiffer material. Simulation results are presented and compared to other correction estimates. Ideal, semi-infinite, and constrained properties of the film and the measurement tools are considered.

  19. 1Plastic deformation and fracture processes in metallic and ceramic nanomaterials... 2007 Advanced Study Center Co. Ltd.

    E-Print Network [OSTI]

    Ovid'ko Ilya A.

    1Plastic deformation and fracture processes in metallic and ceramic nanomaterials... © 2007-mail: ovidko@def.ipme.ru PLASTIC DEFORMATION AND FRACTURE PROCESSES IN METALLIC AND CERAMIC NANOMATERIALS at the boundaries between the large grains and nanoscale matrix. In the framework of the model, cracks are generated

  20. Golden-Thompson's inequality for deformed exponentials

    E-Print Network [OSTI]

    Frank Hansen

    2014-10-21T23:59:59.000Z

    Deformed logarithms and their inverse functions, the deformed exponentials, are important tools in the theory of non-additive entropies and non-extensive statistical mechanics. We formulate and prove counterparts of Golden-Thompson's trace inequality for q-exponentials with parameter q in the interval [1,3].

  1. Damage and plastic deformation of reservoir rocks

    E-Print Network [OSTI]

    Ze'ev, Reches

    Damage and plastic deformation of reservoir rocks: Part 1. Damage fracturing Seth Busetti, Kyran mechanics, fluid flow in fractured reservoirs, and geomechanics in nonconventional reservoirs. Kyran Mish finite deformation of reservoir rocks. We present an at- tempt to eliminate the main limitations

  2. Multitrace deformation of the Aharony-Bergman-Jafferis-Maldacena theory

    SciTech Connect (OSTI)

    Craps, Ben [Theoretische Natuurkunde, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); International Solvay Institutes, Boulevard du Triomphe, ULB-C.P.231, B-1050 Brussels (Belgium); Hertog, Thomas [International Solvay Institutes, Boulevard du Triomphe, ULB-C.P.231, B-1050 Brussels (Belgium); APC, Universite Paris 7, 10 rue A.Domon et L.Duquet, 75205 Paris (France); Turok, Neil [Perimeter Institute for Theoretical Physics, 31 Caroline Street N, Waterloo, Ontario N2L2Y5, Canada, and DAMTP, CMS, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)

    2009-10-15T23:59:59.000Z

    Motivated by the study of big crunch singularities in asymptotically AdS{sub 4} space-times, we consider a marginal triple trace deformation of Aharony-Bergman-Jafferis-Maldacena (ABJM) theory. The deformation corresponds to adding a potential which is unbounded below. In a 't Hooft large N limit, the beta function for the triple trace deformation vanishes, which is consistent with the near-boundary behavior of the bulk fields. At the next order in the 1/N expansion, the triple trace couplings exhibit nontrivial running, which we analyze explicitly in the limit of zero 't Hooft coupling, in which the model reduces to an O(N)xO(N) vector model with large N. In this limit, we establish the existence of a perturbative UV fixed point, and we comment on possible nonperturbative effects. We also show that the bulk analysis leading to big crunch singularities extends to the Z{sub k} orbifold models dual to ABJM theory.

  3. On beta-deformations and Noncommutativity

    E-Print Network [OSTI]

    Manuela Kulaxizi

    2006-10-30T23:59:59.000Z

    We elucidate the connection between the N=1 beta-deformed SYM theory and noncommutativity. Our starting point is the T-duality generating transformation involved in constructing the gravity duals of both beta-deformed and noncommutative gauge theories. We show that the two methods can be identified provided that a particular submatrix of the O(3,3,R) group element employed in the former case, is interpreted as the noncommutativity parameter associated with the deformation of the transverse space. It is then explained how to construct the matrix in question, relying solely on information extracted from the gauge theory Lagrangian and basic notions of AdS/CFT. This result may provide an additional tool in exploring deformations of the N=4 SYM theory. Finally we use the uncovered relationship between beta-deformations and noncommutativity to find the gravity background dual to a noncommutative gauge theory with beta-type noncommutativity parameter.

  4. Steady state deformation of the Coso Range, east central California...

    Open Energy Info (EERE)

    from satellite radar interferometry Abstract Observations of deformation from 1992 to 1997 in the southern Coso Range using satellite radar interferometry show deformation rates...

  5. Report on the IUTAM symposium on viscoelastic fluid mechanics: effects of molecular modeling

    E-Print Network [OSTI]

    Shaqfeh, Eric

    . These include a variety of optical polarimetry methods, scattering techniques (light and neutron primarily

  6. Author's personal copy Viscoelastic properties of model segments of collagen molecules

    E-Print Network [OSTI]

    Buehler, Markus J.

    -up description of elastic and viscous properties form the properties of the tissue basic building blocks. © 2011 through the generation of muscular forces that are then transmitted to joints. The force transmission building block in vertebrates, and is the principal protein that provides mechanical stability, elasticity

  7. A Discrete Complex Compliance Spectra Model of the Nonlinear Viscoelastic Creep and Recovery

    E-Print Network [OSTI]

    Kumar, Vipin

    , easily fit functions of stress. The new method is applied to a set of microcellular polycarbonate polycarbonate material system are very sensitive to relative density and therefore, this material system. Such foams have been created in polycarbonate using carbon dioxide as the gas for bubble nucleation.2

  8. Non-Linear Drying Diffusion and Viscoelastic Drying Shrinkage Modeling in Hardened Cement Pastes 

    E-Print Network [OSTI]

    Leung, Chin K.

    2010-07-14T23:59:59.000Z

    of diffusion rate over short drops of ambient relative humidity. Techniques to determine drying isotherms prior to full equilibration of mass loss, as well as converting mass loss into concentration of water vapor were developed. Using the measured water vapor...

  9. Modeling electrospinning process and a numerical scheme using Lattice Boltzmann method to simulate viscoelastic fluid flows

    E-Print Network [OSTI]

    Karra, Satish

    2009-05-15T23:59:59.000Z

    of secondary electric field on electrospinning process and whipping instability. It is observed that the external secondary field unwinds the jet spirals, reduces the whipping instability and increases the tension in the fiber. Lattice Boltzmann method (LBM...

  10. Modeling of three-dimensional viscoelastic flows with free surfaces using a finite element method

    E-Print Network [OSTI]

    Adrian, David Joseph

    2010-01-01T23:59:59.000Z

    A framework and code have been developed to simulate fiber and film processes; the code can handle three-dimensional, isothermal, incompressible, creeping flow of a Giesekus fluid with free surfaces at infinite capillary ...

  11. Biaxial Deformations of Rubber: Entanglements or Elastic Fluctuations?

    E-Print Network [OSTI]

    Xiangjun Xing

    2010-11-01T23:59:59.000Z

    The classical theory of rubber elasticity fails in the regime of large deformation. The un- derlying physical mechanism has been under debate for long time. In this work, we test the recently proposed mechanism of thermal elastic fluctuations by Xing, Goldbart and Radzi- hovsky1 against the biaxial stress-strain data of three distinct polymer networks with very different network structures, synthesized by Urayama2 and Kawabata3 respectively. We find that both the two parameters version and the one-parameter version of the XGR theory provide satisfactory description of the elasticity in whole deformation range. For comparison, we also fit the same sets of data using the slip-link model by Edwards and Vilgis with four parameters. The fitting qualities of two theories are found to be comparable.

  12. Forced transport of deformable containers through narrow constrictions

    E-Print Network [OSTI]

    Remy Kusters; Thijs van der Heijden; Badr Kaoui; Jens Harting; Cornelis Storm

    2014-11-19T23:59:59.000Z

    We study, numerically and analytically, the forced transport of deformable containers through a narrow constriction. Our central aim is to quantify the competition between the constriction geometry and the active forcing, regulating whether and at which speed a container may pass through the constriction and under what conditions it gets stuck. We focus, in particular, on the interrelation between the force that propels the container and the radius of the channel, as these are the external variables that may be directly controlled in both artificial and physiological settings. We present Lattice-Boltzmann simulations that elucidate in detail the various phases of translocation, and present simplified analytical models that treat two limiting types of these membrane containers: deformational energy dominated by the bending or stretching contribution. In either case we find excellent agreement with the full simulations, and our results reveal that not only the radius but also the length of the constriction determines whether or not the container will pass.

  13. Optical Deformations in Solar Glass Filters for High Precision Astrometry

    E-Print Network [OSTI]

    Sigismondi, Costantino; Boscardin, Sérgio Calderari; Penna, Jucira Lousada; Reis-Neto, Eugênio

    2015-01-01T23:59:59.000Z

    Measuring the solar diameter at all position angles gives the complete figure of the Sun. Their asphericities have implications in classical physics and general relativity, and the behavior of the optical systems used in the direct measurements is to be known accurately. A solar filter is a plane-parallel glass with given absorption, and here we study the departures from the parallelism of the faces of a crystal slab 5 mm thick, because of static deformations. These deformations are rescaled to the filter's dimensions. Related to the Solar Disk Sextant experiment and to the Reflecting Heliometer of Rio de Janeiro a simplified model of the influences of the inclination between the external and the internal surfaces of a glass solar filter, is discussed.

  14. Evaluation of the relationship between the effective strain and the springback behavior during the deformation of metallic glass ribbons

    SciTech Connect (OSTI)

    Lee, M H [Ames Laboratory; Park, E S [Samsung Electronics Co., LTD; Ott, R T [Ames Laboratory; Kim, B S [Korea Institute of Industrial Technology; Eckert, J [Institute for Complex Materials

    2014-08-11T23:59:59.000Z

    We evaluated the role of effective strain on the plasticity of metallic glasses related to springback phenomena in both ductile Zr-based metallic glass and brittle Hf-based metallic glass. Experimental investigations of the deformation behavior and the intrinsic mechanical properties of metallic glass were performed by room temperature L-bending deformation. The modeling analysis clearly shows that an inhomogeneous effective strain for initiating shear band is generated during deformation, with the brittleness of a metallic glass being dependent on the effective strain reaching the critical fracture strain of the glass. The combined experimental and modeling results reveal broad and general criteria that should allow for deformability of a wide-variety of glass-forming alloys by adjusting the effective strain during deformation.

  15. Deformation of Silica Aerogel During Fluid Adsorption

    E-Print Network [OSTI]

    Tobias Herman; James Day; John Beamish

    2005-06-30T23:59:59.000Z

    Aerogels are very compliant materials - even small stresses can lead to large deformations. In this paper we present measurements of the linear deformation of high porosity aerogels during adsorption of low surface tension fluids, performed using a Linear Variable Differential Transformer (LVDT). We show that the degree of deformation of the aerogel during capillary condensation scales with the surface tension, and extract the bulk modulus of the gel from the data. Furthermore we suggest limits on safe temperatures for filling and emptying low density aerogels with helium.

  16. Synergistic Effect of coal blends on thermoplasticity evaluated using a temperature-variable dynamic viscoelastic measurement

    SciTech Connect (OSTI)

    Toshimasa Takanohashi; Takahiro Shishido; Ikuo Saito; Kensuke Masaki; Atsushi Dobashi; Kiyoshi Fukada [National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan)

    2006-12-15T23:59:59.000Z

    To maximize the conversion of low-quality coal into good coke, we investigated the thermoplasticity of various binary blends of caking coals with slightly or noncaking coals using a dynamic viscoelastic technique with a temperature-variable rheometer. Coal blend samples were prepared by mixing two coals (1:1 by weight), which were heated from room temperature to 600 C at a rate of 3-80{sup o}C/min. At the slow rate of 3{sup o}C/min, the blends had a tan {delta} that was generally lower than the calculated value, showing that a negative interaction caused a loss of thermoplasticity. In contrast, at the rapid heating rate of 80{sup o}C/min, the tan {delta} of some blends was higher than the calculated value, indicating a positive interaction that enhanced the thermoplasticity. With rapid heating, the thermoplasticity of each coal itself increased, and their thermoplastic temperature ranges widened with rapid heating. Therefore, rapid heating was effective at converting these coal blends into good cokes. Moreover, even with slow heating, when a combination of coals (Gregory:Enshu, 1:1) showing some thermoplasticity in nearly the same temperature range was blended, a desirable synergistic effect of the blend was obtained. This suggests that blending coal with an overlapping thermoplastic temperature range is important for the synergistic effect, regardless of the heating rate. 15 refs., 9 figs., 2 tabs.

  17. A fluid pressure and deformation analysis for geological sequestration of carbon dioxide

    SciTech Connect (OSTI)

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

    2012-06-07T23:59:59.000Z

    We present a hydro-mechanical model and deformation analysis for geological sequestration of carbon dioxide. The model considers the poroelastic effects by taking into account the two-way coupling between the geomechanical response and the fluid flow process in greater detail. In order for analytical solutions, the simplified hydro-mechanical model includes the geomechanical part that relies on the theory of linear elasticity, while the fluid flow is based on the Darcy’s law. The model was derived through coupling the two parts using the standard linear poroelasticity theory. Analytical solutions for fluid pressure field were obtained for a typical geological sequestration scenario and the solutions for ground deformation were obtained using the method of Green’s function. Solutions predict the temporal and spatial variation of fluid pressure, the effect of permeability and elastic modulus on the fluid pressure, the ground surface uplift, and the radial deformation during the entire injection period.

  18. Normal Ordering for Deformed Boson Operators and Operator-valued Deformed Stirling Numbers

    E-Print Network [OSTI]

    Jacob Katriel; Maurice Kibler

    2000-01-02T23:59:59.000Z

    The normal ordering formulae for powers of the boson number operator $\\hat{n}$ are extended to deformed bosons. It is found that for the `M-type' deformed bosons, which satisfy $a a^{\\dagger} - q a^{\\dagger} a = 1$, the extension involves a set of deformed Stirling numbers which replace the Stirling numbers occurring in the conventional case. On the other hand, the deformed Stirling numbers which have to be introduced in the case of the `P-type' deformed bosons, which satisfy $a a^{\\dagger} - q a^{\\dagger} a = q^{-\\hat{n}}$, are found to depend on the operator $\\hat{n}$. This distinction between the two types of deformed bosons is in harmony with earlier observations made in the context of a study of the extended Campbell-Baker-Hausdorff formula.

  19. Orienting Deformable Polygonal Parts without Sensors

    E-Print Network [OSTI]

    Kristek, Shawn

    2012-02-14T23:59:59.000Z

    with low-precision robot manipulators and six parts made of four types of materials. The experimental trials resulted in 154 successes, which show the feasibility of deformable parts orienting. The analysis of the failures showed that for success...

  20. Physics-Based Deformable Tongue Visualization

    E-Print Network [OSTI]

    Guo, Xiaohu "Tiger"

    capture data gathered during speech production. Several novel deformation visualization techniques energy is utilized to provide an intuitive low dimensional visualization for the high dimensional sequential motion. Energy-interpolation-based morphing is also equipped to effectively highlight the subtle

  1. Mechanics of deformation of carbon nanotubes

    E-Print Network [OSTI]

    Garg, Mohit, S.M. Massachusetts Institute of Technology

    2005-01-01T23:59:59.000Z

    The deformation mechanics of multi-walled carbon nanotubes (MWCNT) and vertically aligned carbon nanotube (VACNT) arrays were studied using analytical and numerical methods. An equivalent orthotropic representation (EOR) ...

  2. On q-deformed Stirling numbers

    E-Print Network [OSTI]

    Yilmaz Simsek

    2007-11-03T23:59:59.000Z

    The purpose of this article is to introduce q-deformed Stirling numbers of the first and second kinds. Relations between these numbers, Riemann zeta function and q-Bernoulli numbers of higher order are given. Some relations related to the classical Stirling numbers and Bernoulli numbers of higher order are found. By using derivative operator to the generating function of the q-deformed Stirling numbers of the second kinds, a new function is defined which interpolates the q-deformed Stirling numbers of the second kinds at negative integers. The recurrence relations of the Stirling numbers of the first and second kind are given. In addition, relation between q-deformed Stirling numbers and q-Bell numbers is obtained.

  3. Noncommutative scalar fields from symplectic deformation

    SciTech Connect (OSTI)

    Daoud, M. [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34014 Trieste (Italy); Hamama, A. [High Energy Laboratory, Faculty of Sciences, University Mohamed V, P.O. Box 1014, Rabat (Morocco)

    2008-02-15T23:59:59.000Z

    This paper is concerned with the quantum theory of noncommutative scalar fields in two dimensional space-time. It is shown that the noncommutativity originates from the the deformation of symplectic structures. The quantization is performed and the modes expansions of the fields, in the presence of an electromagnetic background, are derived. The Hamiltonian of the theory is given and the degeneracies lifting, induced by the deformation, is also discussed.

  4. Influence of plastic deformation on bimaterial fault rupture directivity

    E-Print Network [OSTI]

    Dmowska, Renata

    Influence of plastic deformation on bimaterial fault rupture directivity Nora DeDontney,1 Elizabeth of the role of the stress state on the distribution of plastic deformation and the direction of preferred in determining the location of plastic deformation. For different orientations, plastic deformation can

  5. Deformation Behavior of Nanoporous Metals

    SciTech Connect (OSTI)

    Biener, J; Hodge, A M; Hamza, A V

    2007-11-28T23:59:59.000Z

    Nanoporous open-cell foams are a rapidly growing class of high-porosity materials (porosity {ge} 70%). The research in this field is driven by the desire to create functional materials with unique physical, chemical and mechanical properties where the material properties emerge from both morphology and the material itself. An example is the development of nanoporous metallic materials for photonic and plasmonic applications which has recently attracted much interest. The general strategy is to take advantage of various size effects to introduce novel properties. These size effects arise from confinement of the material by pores and ligaments, and can range from electromagnetic resonances to length scale effects in plasticity. In this chapter we will focus on the mechanical properties of low density nanoporous metals and how these properties are affected by length scale effects and bonding characteristics. A thorough understanding of the mechanical behavior will open the door to further improve and fine-tune the mechanical properties of these sometimes very delicate materials, and thus will be crucial for integrating nanoporous metals into products. Cellular solids with pore sizes above 1 micron have been the subject of intense research for many years, and various scaling relations describing the mechanical properties have been developed.[4] In general, it has been found that the most important parameter in controlling their mechanical properties is the relative density, that is, the density of the foam divided by that of solid from which the foam is made. Other factors include the mechanical properties of the solid material and the foam morphology such as ligament shape and connectivity. The characteristic internal length scale of the structure as determined by pores and ligaments, on the other hand, usually has only little effect on the mechanical properties. This changes at the submicron length scale where the surface-to-volume ratio becomes large and the effect of free surfaces can no longer be neglected. As the material becomes more and more constraint by the presence of free surfaces, length scale effects on plasticity become more and more important and bulk properties can no longer be used to describe the material properties. Even the elastic properties may be affected as the reduced coordination of surface atoms and the concomitant redistribution of electrons may soften or stiffen the material. If, and to what extend, such length scale effects control the mechanical behavior of nanoporous materials depends strongly on the material and the characteristic length scale associated with its plastic deformation. For example, ductile materials such as metals which deform via dislocation-mediated processes can be expected to exhibit pronounced length scale effects in the sub-micron regime where free surfaces start to constrain efficient dislocation multiplication. In this chapter we will limit our discussion to our own area of expertise which is the mechanical behavior of nanoporous open-cell gold foams as a typical example of nanoporous metal foams. Throughout this chapter we will review our current understanding of the mechanical properties of nanoporous open-cell foams including both experimental and theoretical studies.

  6. Material models of dark energy

    E-Print Network [OSTI]

    Jonathan A. Pearson

    2014-09-16T23:59:59.000Z

    We review and develop a new class of "dark energy" models, in which the relativistic theory of solids is used to construct material models of dark energy. These are models which include the effects of a continuous medium with well defined physical properties at the level of linearized perturbations. The formalism is constructed for a medium with arbitrary symmetry, and then specialised to isotropic media (which will be the case of interest for the majority of cosmological applications). We develop the theory of relativistic isotropic viscoelastic media whilst keeping in mind that we ultimately want to observationally constrain the allowed properties of the material model. We do this by obtaining the viscoelastic equations of state for perturbations (the entropy and anisotropic stress), as well as identifying the consistent corner of the theory which has constant equation of state parameter $\\dot{w}=0$. We also connect to the non-relativistic theory of solids, by identifying the two quadratic invariants that are needed to construct the energy-momentum tensor, namely the Rayleigh dissipation function and Lagrangian for perturbations. Finally, we develop the notion that the viscoelastic behavior of the medium can be thought of as a non-minimally coupled massive gravity theory. This also provides a tool-kit for constructing consistent generalizations of coupled dark energy theories.

  7. Analysis of the Deformation Behavior of Mg-RE and Mg-Li Alloys using In-situ Energy-dispersive Synchrotron X-ray Diffraction

    SciTech Connect (OSTI)

    Lentz, Martin [Technische Universität Berlin, Institute of Material Science and Technologies - Metallic Materials; Clausen, Bjorn [Los Alamos National Laboratory; Reimers, Walter [Technische Universität Berlin, Institute of Material Science and Technologies - Metallic Materials

    2012-08-06T23:59:59.000Z

    EPSC-Model is able to predict the complex deformation behavior of Mg-RE and Mg-Li alloys within a wide range of strains. Modification of the texture by RE-elements and the addition of Li increases the activity of slip systems at low strains - Reorientation due to twinning is stretch over a larger range of plastic deformation. Deformation at high strains is realized mainly by the basal and the -pyramidal slip systems.

  8. CURRICULUM VITAE BRIDGET R. SMITH-KONTER

    E-Print Network [OSTI]

    Smith-Konter, Bridget

    tide gauge records · Refinement of 3D semi-analytic crustal deformation model of San Andreas Fault · Development, verification, & application of 3D elastic and viscoelastic body force model · Shuttle Radar tide gauge observations with 100-year vertical deformation models of California earthquake history; PI

  9. Deformations of infrared-conformal theories in two dimensions

    E-Print Network [OSTI]

    Oscar Akerlund; Philippe de Forcrand

    2014-10-05T23:59:59.000Z

    We study two exactly solvable two-dimensional conformal models, the critical Ising model and the Sommerfield model, on the lattice. We show that finite-size effects are important and depend on the aspect ratio of the lattice. In particular, we demonstrate how to obtain the correct massless behavior from an infinite tower of finite-size-induced masses and show that it is necessary to first take the cylindrical geometry limit in order to get correct results. In the Sommerfield model we also introduce a mass deformation to measure the mass anomalous dimension, $\\gamma_m$. We find that the explicit scale breaking of the lattice setup induces corrections which must be taken into account in order to reproduce $\\gamma_m$ at the infrared fixed point. These results can be used to improve the methodology in the search for the conformal window in QCD-like theories with many flavors.

  10. Limits of isotropic plastic deformation of Bangkok clay

    E-Print Network [OSTI]

    P. Evesque

    2005-07-08T23:59:59.000Z

    A model assuming incremental plastic isotropic response has been recently proposed to model the deformation of isotropic packing of grains, in the small-strain range. It is used here on over-consolidated remould clay, to interpret the small-strain range behaviour obtained in [1,2] on Bangkok clay. The data published in [1,2] at constant volume are also used here to measure the size of the domain of validity in the (q/(M'p), p/po) plane, where po is the over-consolidation isotropic pressure, p is the mean stress and q the deviatoric stress, q . So, it is shown that the model works also for clay. This enlarges the application domain of model [3,4] to soft clay with OCR larger than 1.2 to 1.5. Pacs # : 45.70.-n ; 62.20.Fe ; 83.80.Fg, 83.80.Hj

  11. Semi-microscopic description of the double backbending in some deformed even-even rare earth nuclei

    E-Print Network [OSTI]

    R. Budaca; A. A. Raduta

    2013-01-25T23:59:59.000Z

    A semi-microscopic model to study the neutron and proton induced backbending phenomena in some deformed even-even nuclei from the rare earth region, is proposed. The space of particle-core states is defined by the angular momentum projection of a quadrupole deformed product state. The backbending phenomena are described by mixing four rotational bands, defined by a set of angular momentum projected states, and a model Hamiltonian describing a set of paired particles moving in a deformed mean field and interacting with a phenomenological deformed core. The ground band corresponds to the configuration where all particles are paired while the other rotational bands are built on one neutron or/and one proton broken pair. Four rare earth even-even nuclei which present the second anomaly in the observed moments of inertia are successfully treated within the proposed model.

  12. Temperature and angular momentum dependence of the quadrupole deformation in sd-shell

    E-Print Network [OSTI]

    P. A. Ganai; J. A. Sheikh; I. Maqbool; R. P. Singh

    2009-06-16T23:59:59.000Z

    Temperature and angular momentum dependence of the quadrupole deformation is studied in the middle of the sd-shell for 28Si and 27Si isotopes using the spherical shell model approach. The shell model calculations have been performed using the standard USD interaction and the canonical partition function constructed from the calculated eigen-solutions. It is shown that the extracted average quadrupole moments show a transitional behavior as a function of temperature and the inferred transitional temperature is shown to vary with angular-momentum. The quadrupole deformation of the individual eigen-states is also analyzed.

  13. Dangerous Liouville Wave -- exactly marginal but non-conformal deformation

    E-Print Network [OSTI]

    Chiu Man Ho; Yu Nakayama

    2008-07-26T23:59:59.000Z

    We give a non-trivially interacting field theory example of scale invariant but non-conformal field theory. The model is based on the exactly solvable Liouville field theory coupled with free scalars deformed by an exactly marginal operator. We show non-vanishing of the trace of the energy-momentum tensor by using the quantum Schwinger-Dyson equation for the Liouville field theory, which is a sophistication of the quantum higher equations of motion for the Liouville field theory introduced by Alyosha Zamolodchikov. Possibly dangerous implications for the super-critical string theory will be discussed.

  14. Density fluctuations in $?$-deformed inflationary universe

    E-Print Network [OSTI]

    Hyeong-Chan Kim; Jae Hyung Yee; Chaiho Rim

    2005-10-27T23:59:59.000Z

    We study the spectrum of metric fluctuation in $\\kappa$-deformed inflationary universe. We write the theory of scalar metric fluctuations in the $\\kappa-$deformed Robertson-Walker space, which is represented as a non-local theory in the conventional Robertson-Walker space. One important consequence of the deformation is that the mode generation time is naturally determined by the structure of the $\\kappa-$deformation. We expand the non-local action in $H^2/\\kappa^2$, with $H$ being the Hubble parameter and $\\kappa$ the deformation parameter, and then compute the power spectra of scalar metric fluctuations both for the cases of exponential and power law inflations up to the first order in $H^2/\\kappa^2$. We show that the power spectra of the metric fluctuation have non-trivial corrections on the time dependence and on the momentum dependence compared to the commutative space results. Especially for the power law inflation case, the power spectrum for UV modes is weakly blue shifted early in the inflation and its strength decreases in time. The power spectrum of far-IR modes has cutoff proportional to $k^3$ which may explain the low CMB quadrupole moment.

  15. On a Model of Superconductivity and Biology

    E-Print Network [OSTI]

    Monica De Angelis

    2012-03-02T23:59:59.000Z

    The paper deals with a semilinear integrodifferential equation that characterizes several dissipative models of Viscoelasticity, Biology and Superconductivity. The initial - boundary problem with Neumann conditions is analyzed. When the source term F is a linear function, then the explicit solution is obtained. When F is non linear, some results on existence, uniqueness and a priori estimates are deduced. As example of physical model the reaction - diffusion system of Fitzhugh Nagumo is considered.

  16. Derivation of an optical potential for statically deformed rare-earth nuclei from a global spherical potential

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

    Nobre, G. P. A.; Palumbo, A.; Herman, M.; Brown, D.; Hoblit, S.; Dietrich, F. S.

    2015-02-01T23:59:59.000Z

    The coupled-channel theory is a natural way of treating nonelastic channels, in particular those arising from collective excitations characterized by nuclear deformations. A proper treatment of such excitations is often essential to the accurate description of experimental nuclear-reaction data and to the prediction of a wide variety of scattering observables. Stimulated by recent work substantiating the near validity of the adiabatic approximation in coupled-channel calculations for scattering on statically deformed nuclei, we explore the possibility of generalizing a global spherical optical model potential (OMP) to make it usable in coupled-channel calculations on this class of nuclei. To do this, wemore »have deformed the Koning-Delaroche global spherical potential for neutrons, coupling a sufficient number of states of the ground state band to ensure convergence. We present an extensive study of the effects of collective couplings and nuclear deformations on integrated cross sections as well as on angular distributions for neutron-induced reactions on statically deformed nuclei in the rare-earth region. We choose isotopes of three rare-earth elements (Gd, Ho, W), which are known to be nearly perfect rotors, to exemplify the results of the proposed method. Predictions from our model for total, elastic and inelastic cross sections, as well as for elastic and inelastic angular distributions, are in reasonable agreement with measured experimental data. These results suggest that the deformed Koning-Delaroche potential provides a useful regional neutron optical potential for the statically deformed rare earth nuclei.« less

  17. Derivation of an optical potential for statically deformed rare-earth nuclei from a global spherical potential

    E-Print Network [OSTI]

    G. P. A. Nobre; A. Palumbo; F. S. Dietrich; M. Herman; D. Brown; S. Hoblit

    2014-12-22T23:59:59.000Z

    The coupled-channel theory is a natural way of treating nonelastic channels, in particular those arising from collective excitations characterized by nuclear deformations. A proper treatment of such excitations is often essential to the accurate description of experimental nuclear-reaction data and to the prediction of a wide variety of scattering observables. Stimulated by recent work substantiating the near validity of the adiabatic approximation in coupled-channel calculations for scattering on statically deformed nuclei, we explore the possibility of generalizing a global spherical optical model potential (OMP) to make it usable in coupled-channel calculations on this class of nuclei. To do this, we have deformed the Koning-Delaroche global spherical potential for neutrons, coupling a sufficient number of states of the ground state band to ensure convergence. We present an extensive study of the effects of collective couplings and nuclear deformations on integrated cross sections as well as on angular distributions for neutron-induced reactions on statically deformed nuclei in the rare-earth region. We choose isotopes of three rare-earth elements (Gd, Ho, W), which are known to be nearly perfect rotors, to exemplify the results of the proposed method. Predictions from our model for total, elastic and inelastic cross sections, as well as for elastic and inelastic angular distributions, are in reasonable agreement with measured experimental data. These results suggest that the deformed Koning-Delaroche potential provides a useful regional neutron optical potential for the statically deformed rare earth nuclei.

  18. Derivation of an optical potential for statically deformed rare-earth nuclei from a global spherical potential

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

    Nobre, G. P. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Palumbo, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Herman, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hoblit, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Dietrich, F. S. [Walnut Creek, CA (United States)

    2015-02-01T23:59:59.000Z

    The coupled-channel theory is a natural way of treating nonelastic channels, in particular those arising from collective excitations characterized by nuclear deformations. A proper treatment of such excitations is often essential to the accurate description of experimental nuclear-reaction data and to the prediction of a wide variety of scattering observables. Stimulated by recent work substantiating the near validity of the adiabatic approximation in coupled-channel calculations for scattering on statically deformed nuclei, we explore the possibility of generalizing a global spherical optical model potential (OMP) to make it usable in coupled-channel calculations on this class of nuclei. To do this, we have deformed the Koning-Delaroche global spherical potential for neutrons, coupling a sufficient number of states of the ground state band to ensure convergence. We present an extensive study of the effects of collective couplings and nuclear deformations on integrated cross sections as well as on angular distributions for neutron-induced reactions on statically deformed nuclei in the rare-earth region. We choose isotopes of three rare-earth elements (Gd, Ho, W), which are known to be nearly perfect rotors, to exemplify the results of the proposed method. Predictions from our model for total, elastic and inelastic cross sections, as well as for elastic and inelastic angular distributions, are in reasonable agreement with measured experimental data. These results suggest that the deformed Koning-Delaroche potential provides a useful regional neutron optical potential for the statically deformed rare earth nuclei.

  19. Plastic Deformation of 2D Crumpled Wires

    E-Print Network [OSTI]

    M A F Gomes; V P Brito; A S O Coelho; C C Donato

    2008-11-17T23:59:59.000Z

    When a single long piece of elastic wire is injected trough channels into a confining two-dimensional cavity, a complex structure of hierarchical loops is formed. In the limit of maximum packing density, these structures are described by several scaling laws. In this paper it is investigated this packing process but using plastic wires which give origin to completely irreversible structures of different morphology. In particular, it is studied experimentally the plastic deformation from circular to oblate configurations of crumpled wires, obtained by the application of an axial strain. Among other things, it is shown that in spite of plasticity, irreversibility, and very large deformations, scaling is still observed.

  20. Deformation of contour and Hawking temperature

    E-Print Network [OSTI]

    Chikun Ding; Jiliang Jing

    2010-01-19T23:59:59.000Z

    It was found that, in an isotropic coordinate system, the tunneling approach brings a factor of 1/2 for the Hawking temperature of a Schwarzschild black hole. In this paper, we address this kind of problem by studying the relation between the Hawking temperature and the deformation of integral contour for the scalar and Dirac particles tunneling. We find that correct Hawking temperature can be obtained exactly as long as the integral contour deformed corresponding to the radial coordinate transform if the transformation is a non-regular or zero function at the event horizon.

  1. A Noncommutative Deformation of Topological Field Theory

    E-Print Network [OSTI]

    Hugo Garcia-Compean; Pablo Paniagua

    2004-02-21T23:59:59.000Z

    Cohomological Yang-Mills theory is formulated on a noncommutative differentiable four manifold through the $\\theta$-deformation of its corresponding BRST algebra. The resulting noncommutative field theory is a natural setting to define the $\\theta$-deformation of Donaldson invariants and they are interpreted as a mapping between the Chevalley-Eilenberg homology of noncommutative spacetime and the Chevalley-Eilenberg cohomology of noncommutative moduli of instantons. In the process we find that in the weak coupling limit the quantum theory is localized at the moduli space of noncommutative instantons.

  2. PLASTIC DEFORMATION OF CRYSTALS: ANALYTICAL AND COMPUTER SIMULATION STUDIES OF DISLOCATION GLIDE

    E-Print Network [OSTI]

    Altintas, Sabri

    2011-01-01T23:59:59.000Z

    in Rate Processes in Plastic Deformation of Materials, J. C.PLASTIC DEFORMATION OF CRYSTALS: ANALYTICAL AND COMPUTERCAPTIONS FIGURES - iii - PLASTIC DEFORMATION OF CRYSTALS:

  3. Joining of advanced materials by superplastic deformation

    DOE Patents [OSTI]

    Goretta, Kenneth C. (Downers Grove, IL); Routbort, Jules L. (Hinsdale, IL); Gutierrez-Mora, Felipe (Woodridge, IL)

    2008-08-19T23:59:59.000Z

    A method for utilizing superplastic deformation with or without a novel joint compound that leads to the joining of advanced ceramic materials, intermetallics, and cermets. A joint formed by this approach is as strong as or stronger than the materials joined. The method does not require elaborate surface preparation or application techniques.

  4. Deformation and Forming of Joined Materials

    SciTech Connect (OSTI)

    Carsley, John; Hovanski, Yuri; Clarke, Kester D.; Krajewski, Paul E.

    2014-09-23T23:59:59.000Z

    Introductory article to a set of invited papers from the TMS committee on shaping and forming. This paper introduces a set of papers that were prepared to discussing the deformation and forming of joined materials, and to announce an upcoming symposium at the 2015 MS&T meeting in Columbus Ohio.

  5. FORMAL DEFORMATION THEORY 1. Introduction 1

    E-Print Network [OSTI]

    de Jong, A. Johan

    . Lifts of objects 50 17. Schlessinger's theorem on prorepresentable functors 52 18. Infinitesimal paper [TV10], which discusses deformation theory with groupoids but in less generality than we do here is one that satisfies the infinitesimal lifting criterion for objects, see Section 8. This is analogous

  6. Experimental deformation of natural and synthetic dolomite

    E-Print Network [OSTI]

    Davis, Nathan Ernest

    2005-11-01T23:59:59.000Z

    Natural and hot isostatically pressed dolomite aggregates were experimentally deformed at effective pressures of Pe = 50 ?? 400 MPa, temperatures of 400 ?? 850??C, and strain rates of ?& = 1.2x10-4 s-1 to 1.2x10-7 s-1. Coarse- and fine-grained...

  7. Damage and plastic deformation of reservoir rocks

    E-Print Network [OSTI]

    Ze'ev, Reches

    Damage and plastic deformation of reservoir rocks: Part 2. Propagation of a hydraulic fracture Seth fracture and fault mechanics, fluid flow in fractured reservoirs, and geome- chanics in nonconventional the development of complex hydraulic fractures (HFs) that are commonly ob- served in the field and in experiments

  8. Tidal deformations of a spinning compact object

    E-Print Network [OSTI]

    Paolo Pani; Leonardo Gualtieri; Andrea Maselli; Valeria Ferrari

    2015-03-25T23:59:59.000Z

    The deformability of a compact object induced by a perturbing tidal field is encoded in the tidal Love numbers, which depend sensibly on the object's internal structure. These numbers are known only for static, spherically-symmetric objects. As a first step to compute the tidal Love numbers of a spinning compact star, here we extend powerful perturbative techniques to compute the exterior geometry of a spinning object distorted by an axisymmetric tidal field to second order in the angular momentum. The spin of the object introduces couplings between electric and magnetic deformations and new classes of induced Love numbers emerge. For example, a spinning object immersed in a quadrupolar, electric tidal field can acquire some induced mass, spin, quadrupole, octupole and hexadecapole moments to second order in the spin. The deformations are encoded in a set of inhomogeneous differential equations which, remarkably, can be solved analytically in vacuum. We discuss certain subtleties in defining the multipole moments of the central object, which are due to the difficulty in separating the tidal field from the linear response of the object in the solution. By extending the standard procedure to identify the linear response in the static case, we prove analytically that the Love numbers of a Kerr black hole remain zero to second order in the spin. As a by-product, we provide the explicit form for a slowly-rotating, tidally-deformed Kerr black hole to quadratic order in the spin, and discuss its geodesic and geometrical properties.

  9. On Lorentz Transformations in Symplectic Deformations

    SciTech Connect (OSTI)

    Cuesta, R.; Sabido, M. [Departamento de Fisica, DCI-Campus Leon, Universidad de Guanajuato, A.P. E-143, C.P. 37150, Guanajuato (Mexico); Guzman, W. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21945-970, Rio de Janeiro (Brazil)

    2010-07-12T23:59:59.000Z

    In this paper we study noncommutative Lorentz transformations using symplectic deformations. In this framework we define an infinitesimal line element that is invariant under this noncommutative Lorentz transformations. Using the symplectic geometry formalism, we find that noncommutative Lorentz transformations intertwine the canonical momentums with canonical position coordinates.

  10. Deformable Transparent All-Carbon-Nanotube Transistors

    E-Print Network [OSTI]

    Maruyama, Shigeo

    and organic materials16,17 are candidates for next-generation flexible and transparent electronic devices-carbon-nanotube field-effect transistors (CNT- FETs), making use of the flexible yet robust nature of single than those used in other flexible CNT-FETs allowed our devices to be highly deformable without

  11. Atomic picture of elastic deformation in a metallic glass

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

    Wang, X. D.; Aryal, S.; Zhong, C.; Ching, W. Y.; Sheng, H. W.; Zhang, H.; Zhang, D. X.; Cao, Q. P.; Jiang, J. Z.

    2015-03-17T23:59:59.000Z

    The tensile behavior of a Ni??Nb?? metallic glass (MG) has been studied by using ab initio density functional theory (DFT) calculation with a large cell containing 1024 atoms (614 Ni and 410 Nb). We provide insight into how a super elastic limit can be achieved in a MG. Spatially inhomogeneous responses of single atoms and also major polyhedra are found to change greatly with increasing external stress when the strain is over 2%, causing the intrinsically viscoelastic behavior. We uncover the origin of the observed super elastic strain limit under tension (including linear and viscoelastic strains) in small-sized MG samples,more »mainly caused by inhomogeneous distribution of excess volumes in the form of newly formed subatomic cavities.« less

  12. Mesh Puppetry: Cascading Optimization of Mesh Deformation with Inverse Kinematics

    E-Print Network [OSTI]

    Desbrun, Mathieu

    approach builds upon traditional rigging by optimizing skeleton position and vertex weights. Keywords: Mesh deformation, nonlinear optimization, inverse kinematics, geometry processing. 1 Introduction. To allow for more global and complex deforma- tion, many authors proposed to cast mesh deformation

  13. Deformability of Plasmodium falciparum parasitized red blood cells

    E-Print Network [OSTI]

    Mills, John Philip, Ph. D. Massachusetts Institute of Technology

    2007-01-01T23:59:59.000Z

    The biophysical properties of the human red blood cell (RBC) permit large deformations required for passage through narrow capillaries and spleen sinusoids. Several pathologic conditions alter RBC deformability that can ...

  14. Effects of cryogenic equal channel angular deformation on copper 101

    E-Print Network [OSTI]

    Horan, Christopher Sean

    2001-01-01T23:59:59.000Z

    101 was cold worked by being subjected to severe plastic deformation (SPD) at room temperature (23 °C) and at -196 °C under liquid nitrogen. Cold working was imparted by equal channel angular deformation (ECAD). Before extrusions were performed, a...

  15. Effects of subsurface fracture interactions on surface deformation

    E-Print Network [OSTI]

    Jerry, Ruel (Ruel Valentine)

    2013-01-01T23:59:59.000Z

    Although the surface deformation resulting from the opening of a single fracture in a layered elastic half-space resembles the observed deformation at the InSalah site, it seems unlikely that only a single fracture is ...

  16. Severe plastic deformation of difficult-to-work alloys

    E-Print Network [OSTI]

    Yapici, Guney Guven

    2004-09-30T23:59:59.000Z

    The present work aims to reveal the microstructural evolution and post-processing mechanical behavior of difficult-to-work alloys upon severe plastic deformation. Severe plastic deformation is applied using equal channel angular extrusion (ECAE...

  17. Path Planning for Deformable Linear Objects Mark Moll, Member, IEEE and Lydia E. Kavraki, Member, IEEE

    E-Print Network [OSTI]

    Kavraki, Lydia E.

    -like robots. Index Terms-- path planning, deformation, minimal-energy curves, modeling, differential geometry of a wire subject to manipulation constraints. These configurations correspond to minimal-energy curves. By restricting the planner to minimal-energy curves, the execution of a path becomes easier. Our curve

  18. Feedback Control for Steering Needles Through 3D Deformable Tissue Using Helical Paths

    E-Print Network [OSTI]

    O'Brien, James F.

    Feedback Control for Steering Needles Through 3D Deformable Tissue Using Helical Paths Kris Hauser controller that steers a needle along 3D helical paths, and varies the helix radius to correct a model predictive control framework that chooses a needle twist rate such that the predicted helical

  19. Global optimization-based deformable meshes for surface extraction from medical

    E-Print Network [OSTI]

    Neumaier, Arnold

    (GAGR). By global optimization of the energy of the de- formable models, we are capable of reducingGlobal optimization-based deformable meshes for surface extraction from medical images Jussi Tohka, Dual surface minimization (DSM) and a hybrid of real-coded genetic algorithms and a greedy algorithm

  20. Reusable Skinning Templates Using Cage-based Deformations Qian-Yi Zhou2

    E-Print Network [OSTI]

    Southern California, University of

    Reusable Skinning Templates Using Cage-based Deformations Tao Ju1 Qian-Yi Zhou2 Michiel van de- lows skinning solutions to be shared and reused, and they allow a user to quickly explore many possible template. Skinning templates can be shared by users because they are not represented in a model

  1. Learning Deformable Action Templates from Cluttered Videos Benjamin Yao and Song-Chun Zhu

    E-Print Network [OSTI]

    Zhu, Song Chun

    Learning Deformable Action Templates from Cluttered Videos Benjamin Yao and Song-Chun Zhu cluttered real-world videos with weak supervisions. In our generative model, an action template human actions from real-world videos, we use a three- step semi-supervised learning procedure. 1

  2. The Role of Climate in the Deformation of a Fold and Thrust Belt

    E-Print Network [OSTI]

    Steen, Sean Kristian

    2012-02-14T23:59:59.000Z

    and uplifted in large folds. In order to test this and related ideas in a natural example, we have compared modeled rainfall to measured thrust sheet displacement, geometry, and internal deformation in the Appalachian fold and thrust belt. We use mean annual...

  3. q-deformed logistic map with delay feedback

    E-Print Network [OSTI]

    Manish Dev Shrimali; Subhashish Banerjee

    2012-03-14T23:59:59.000Z

    The delay logistic map with two types of q-deformations: Tsallis and Quantum-group type are studied. The stability of the map and its bifurcation scheme is analyzed as a function of the deformation and delay feedback parameters. Chaos is suppressed in a certain region of deformation and feedback parameter space. The steady state obtained by delay feedback is maintained in one type of deformation while chaotic behavior is recovered in another type with increasing delay.

  4. Lattice deformation coupling of the electro-optic Kerr effect in liquid crystalline cholesteric blue phases

    E-Print Network [OSTI]

    Hiroyuki Yoshida; Shuhei Yabu; Hiroki Tone; Hirotsugu Kikuchi; Masanori Ozaki

    2013-10-21T23:59:59.000Z

    The electro-optic Kerr effect in cholesteric blue phase liquid crystals is known to occur on sub-millisecond time scales, which is much faster than director reorientation in nematic liquid crystals. Using two-beam interference microscopy, we report the presence of a very slow response in the Kerr effect, with a characteristic time of several seconds or more. Using a simplified model for the reorientation dynamics, we attribute the slow response to the coupling between the local director reorientation and field-induced deformation of the lattice. We provide evidence for our argument by showing that the slow response can be removed by inhibiting lattice deformation through polymer stabilization.

  5. Analysis of the Energy Spectra of Ground States of Deformed Nuclei in rare-earth region

    E-Print Network [OSTI]

    Abdurahim A. Okhunov; G. I. Turaeva; M. U. Khandaker; Noora B. Rosli

    2014-05-28T23:59:59.000Z

    The 62Sm, 64Gd, 64Dy, 70Y b, 72Hf and 74W nuclei are classified as deformed nuclei. Low-lying bands are one of the most fundamental excitation modes in the energy spectra of deformed nuclei. In this paper a theoretical analysis of the experimental data within the phenomenological model is presented. The energy spectra of ground states are calculated. It is found the low-lying spectra of ground band states are in good agreement with the experimental data.

  6. Quantum Logic Gates using q-deformed Oscillators

    E-Print Network [OSTI]

    Debashis Gangopadhyay; Mahendra Nath Sinha Roy

    2006-07-14T23:59:59.000Z

    We show that the quantum logic gates, {\\it viz.} the single qubit Hadamard and Phase Shift gates, can also be realised using q-deformed angular momentum states constructed via the Jordan-Schwinger mechanism with two q-deformed oscillators. {\\it Keywords :} quantum logic gates ; q-deformed oscillators ; quantum computation {\\it PACS:} 03.67.Lx ; 02.20.Uw

  7. Partitioning a Deformed Urban Grid Leonard Hagger Ian Sanders

    E-Print Network [OSTI]

    Wismath, Stephen

    a convex map of the deformed urban grid. These algorithms are very similar and would #12;nd the same convex map of any given deformed urban grid. In this research I present two di#11;erent algorithms to solve this problem. Both are shown to #12;nd a signi#12;cantly better convex map of the deformed urban grid. The #12

  8. Wall Adhesion and Constitutive Modelling of Strong Colloidal Gels

    E-Print Network [OSTI]

    Daniel R. Lester; Richard Buscall; Anthony D. Stickland; Peter J. Scales

    2014-06-24T23:59:59.000Z

    Wall adhesion effects during batch sedimentation of strongly flocculated colloidal gels are commonly assumed to be negligible. In this study in-situ measurements of colloidal gel rheology and solids volume fraction distribution suggest the contrary, where significant wall adhesion effects are observed in a 110mm diameter settling column. We develop and validate a mathematical model for the equilibrium stress state in the presence of wall adhesion under both viscoplastic and viscoelastic constitutive models. These formulations highlight fundamental issues regarding the constitutive modeling of colloidal gels, specifically the relative utility and validity of viscoplastic and viscoelastic rheological models under arbitrary tensorial loadings. The developed model is validated against experimental data, which points toward a novel method to estimate the shear and compressive yield strength of strongly flocculated colloidal gels from a series of equilibrium solids volume fraction profiles over various column widths.

  9. A new deformed Schioberg-type potential and ro-vibrational energies for some diatomic molecules

    E-Print Network [OSTI]

    Omar Mustafa

    2015-04-24T23:59:59.000Z

    We suggest a new deformed Schioberg-type potential for diatomic molecules. We show that it is equivalent to Tietz-Hua oscillator potential. We discuss how to relate our deformed Schi\\"oberg potential to Morse, to Deng-Fan , to the improved Manning-Rosen, and to the deformed modified Rosen-Morse potential models. We transform our potential into a proper form and use the supersymmetric quantization to find a closed form analytical solution for the ro-vibrational energy levels that are highly accurate over a wide range of vibrational and rotational quantum numbers. We discuss our results using 4-diatomic molecules NO, O2, O2+, and N2. Our results turn out to compare excellently with those from a generalized pseudospectral numerical method.

  10. A new deformed Schioberg-type potential and ro-vibrational energies for some diatomic molecules

    E-Print Network [OSTI]

    Omar Mustafa

    2014-09-24T23:59:59.000Z

    We suggest a new deformed Schioberg-type potential for diatomic molecules. We show that it is equivalent to Tietz-Hua oscillator potential. We discuss how to relate our deformed Schioberg potential to Morse, to Deng-Fan, to the improved Manning-Rosen, and to the deformed modified Rosen-Morse potential models. We transform our potential into a proper form and use the supersymmetric quantization to find a closed form analytical solution for the ro-vibrational energy levels that are highly accurate over a wide range of vibrational and rotational quantum numbers. We discuss our results using 6-diatomic molecules H2, HF, N2, NO, O2, and O2. Our results turn out to compare excellently with those from a generalized pseudospectral numerical method.

  11. Neutrinoless Double Beta Decay in Heavy Deformed Nuclei

    E-Print Network [OSTI]

    Jorge G. Hirsch; O. Castaños; P. O. Hess

    1994-07-12T23:59:59.000Z

    The zero neutrino mode of the double beta decay in heavy deformed nuclei is investigated in the framework of the pseudo SU(3) model, which has provided an accurate description of collective nuclear structure and predicted half-lives for the two neutrino mode in good agreement with experiments. In the case of $^{238}U$ the calculated zero neutrino half-life is at least three orders of magnitude greater than the two neutrino one, giving strong support of the identification of the radiochemically determined half-life as being the two neutrino double beta decay. For $^{150}Nd$ the zero neutrino matrix elements are of the order of magnitude of, but lesser than, those evaluated using the QRPA. This result confirms that different nuclear models produce similar zero neutrino matrix elements, contrary to the two neutrino case. Using these pseudo SU(3) results and the upper limit for the neutrino mass we estimate the $\\beta\\beta_{0\

  12. Constitutive Behavior of a Twaron® Fabric/Natural Rubber Composite: Experiments and Modeling

    E-Print Network [OSTI]

    Natarajan, Valliyappan D.

    2011-02-22T23:59:59.000Z

    -mechanisms and molecular features on the macroscopic responses of ballistic fabrics. In the present work, the constitutive behavior of Twaron CT709® fabric/natural rubber (Twaron®/NR) composite is studied using three viscoelasticity models (i.e., a four-parameter Burgers...

  13. Aharonov-Bohm interferences from local deformations in graphene

    E-Print Network [OSTI]

    Fernando de Juan; Alberto Cortijo; María A. H. Vozmediano; Andrés Cano

    2011-05-04T23:59:59.000Z

    One of the most interesting aspects of graphene is the tied relation between structural and electronic properties. The observation of ripples in the graphene samples both free standing and on a substrate has given rise to a very active investigation around the membrane-like properties of graphene and the origin of the ripples remains as one of the most interesting open problems in the system. The interplay of structural and electronic properties is successfully described by the modelling of curvature and elastic deformations by fictitious gauge fields that have become an ex- perimental reality after the suggestion that Landau levels can form associated to strain in graphene and the subsequent experimental confirmation. Here we propose a device to detect microstresses in graphene based on a scanning-tunneling-microscopy setup able to measure Aharonov-Bohm inter- ferences at the nanometer scale. The interferences to be observed in the local density of states are created by the fictitious magnetic field associated to elastic deformations of the sample.

  14. Structural deformation in the offshore Santa Maria basin, California

    SciTech Connect (OSTI)

    Willingham, C.R. (Explorametrics, Carpinteria, CA (United States)); Heck, R.G. (R.G. Heck and Associates, Carpinteria, CA (United States)); Rietman, J.M. (Rietman Consultants, Santa Ana, CA (United States))

    1991-02-01T23:59:59.000Z

    The authors divide the offshore Santa Maria basin into the southern, central, and northern provinces based on the pattern, style, and timing of late Cenozoic deformation. From their analyses of over 2,000 km of CDP seismic data and offshore well data they prepared time structure contour maps for three basin-wide unconformities: top of basement, top of Miocene, and the unconformity between early and late Pliocene chronostratigraphic units. Isochron maps were constructed between these horizons and between the early/late Pliocene unconformity and the sea floor to evaluate timing of the deformation. All maps were converted to depth and isopach values based on a three-dimensional velocity model. The regional structure contour and isopach maps show that the offshore Santa Maria basin is characterized by localized crustal shortening orthogonal to the Pacific/North America plate margin and indications of post-Miocene to recent lateral slip along the eastern basin boundary, the San Simeon/Hosgri fault system.

  15. A Search for Channel Deformation in Irradiated Vanadium Tensile Specimens

    SciTech Connect (OSTI)

    Gelles, David S.; Toloczko, Mychailo B.; Kurtz, Richard J.

    2010-02-26T23:59:59.000Z

    A miniature tensile specimen of V-4Cr-4Ti which had be irradiated in the 17J test at 425°C to 3.7 dpa was mechanically polished, deformed to 3.9% strain at room temperature, and examined by scanning and transmission electron microscopy in order to look for evidence of channel deformation. It was found that uniform deformation can occur without channel deformation, but evidence for channeling was found with channels appearing most prominently after the onset of necking. The channeling occurs on wavy planes with large variations in localized deformation from channel to channel.

  16. Biaxially textured articles formed by plastic deformation

    DOE Patents [OSTI]

    Goyal, Amit (Knoxville, TN)

    2001-01-01T23:59:59.000Z

    A method of preparing a biaxially textured article comprises the steps of providing a metal preform, coating or laminating the preform with a metal layer, deforming the layer to a sufficient degree, and rapidly recrystallizing the layer to produce a biaxial texture. A superconducting epitaxial layer may then be deposited on the biaxial texture. In some embodiments the article further comprises buffer layers, electromagnetic devices or electro-optical devices.

  17. The Minimal Geometric Deformation Approach Extended

    E-Print Network [OSTI]

    Casadio, Roberto; da Rocha, Roldao

    2015-01-01T23:59:59.000Z

    The minimal geometric deformation approach was introduced in order to study the exterior space-time around spherically symmetric self-gravitating systems, like stars or similar astrophysical objects as well, in the Randall-Sundrum brane-world framework. A consistent extension of this approach is developed here, which contains modifications of both the time component and the radial component of a spherically symmetric metric. A modified Schwarzschild geometry is obtained as an example of its simplest application.

  18. A shapeable material without plastic deformation

    E-Print Network [OSTI]

    Naomi Oppenheimer; Thomas A. Witten

    2015-05-06T23:59:59.000Z

    Randomly crumpled sheets have shape memory. In order to understand the basis of this form of memory, we simulate triangular lattices of springs whose lengths are altered to create a topography with multiple potential energy minima. We then deform these lattices into different shapes and investigate their ability to retain the imposed shape when the energy is relaxed. The lattices are able to retain a range of curvatures. Under moderate forcing from a state of local equilibrium, the lattices deform by several percent but return to their retained shape when the forces are removed. By increasing the forcing until an irreversible motion occurs, we find that the transitions between remembered shapes show co-operativity among several springs. For fixed lattice structures, the shape memory tends to decrease as the lattice is enlarged; we propose ways to counter this decrease by modifying the lattice geometry. We survey the energy landscape by displacing individual nodes. An extensive fraction of these nodes proves to be bistable; they retain their displaced position when the energy is relaxed. Bending the lattice to a stable curved state alters the pattern of bistable nodes. We discuss this shapeability in the context of other forms of material memory and contrast it with the shapeability of plastic deformation. We outline the prospects for making real materials based on these principles.

  19. Constitutive modeling of creep of single crystal superalloys

    E-Print Network [OSTI]

    Prasad, Sharat Chand

    2006-10-30T23:59:59.000Z

    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...

  20. q-Deformed KP Hierarchy and q-Deformed Constrained KP Hierarchy

    E-Print Network [OSTI]

    Jingsong He; Yinghua Li; Yi Cheng

    2006-06-15T23:59:59.000Z

    Using the determinant representation of gauge transformation operator, we have shown that the general form of $\\tau$ function of the $q$-KP hierarchy is a q-deformed generalized Wronskian, which includes the q-deformed Wronskian as a special case. On the basis of these, we study the q-deformed constrained KP ($q$-cKP) hierarchy, i.e. $l$-constraints of $q$-KP hierarchy. Similar to the ordinary constrained KP (cKP) hierarchy, a large class of solutions of $q$-cKP hierarchy can be represented by q-deformed Wronskian determinant of functions satisfying a set of linear $q$-partial differential equations with constant coefficients. We obtained additional conditions for these functions imposed by the constraints. In particular, the effects of $q$-deformation ($q$-effects) in single $q$-soliton from the simplest $\\tau$ function of the $q$-KP hierarchy and in multi-$q$-soliton from one-component $q$-cKP hierarchy, and their dependence of $x$ and $q$, were also presented. Finally, we observe that $q$-soliton tends to the usual soliton of the KP equation when $x\\to 0$ and $q\\to 1$, simultaneously.

  1. Gauge theory deformations and novel Yang-Mills Chern-Simons field theories with torsion

    E-Print Network [OSTI]

    Stephen C. Anco

    2004-09-16T23:59:59.000Z

    A basic problem of classical field theory, which has attracted growing attention over the past decade, is to find and classify all nonlinear deformations of linear abelian gauge theories. The first part of this paper summarizes and significantly elaborates a field- theoretic deformation method developed in earlier work. As a key contribution presented here, a universal geometrical structure common to a large class of nonlinear gauge theory examples is uncovered. This structure is derived geometrically from the deformed gauge symmetry and is characterized by a covariant derivative operator plus a nonlinear field strength, related through the curvature of the covariant derivative. The scope of these results encompasses Yang-Mills theory, Freedman-Townsend theory, Einstein gravity theory, in addition to their many interesting types of novel generalizations that have been found in the past several years. The second part of the paper presents a new geometrical type of Yang-Mills generalization in three dimensions motivated from considering torsion in the context of nonlinear sigma models with Lie group targets (chiral theories). The generalization is derived by a deformation analysis of linear abelian Yang-Mills Chern-Simons gauge theory. Torsion is introduced geometrically through a duality with chiral models obtained from the chiral field form of self-dual 2+2 dimensional Yang-Mills theory under reduction to 2+1 dimensions. Field-theoretic and geometric features of the resulting nonlinear gauge theories with torsion are discussed.

  2. Effects of gaps in adhesives that bond elastically deformed panels to parabolic, cylindrical substructures

    SciTech Connect (OSTI)

    Wilson, R.K.; Reuter, R.C. Jr.

    1982-03-01T23:59:59.000Z

    In previous studies of the mechanical behavior of line focusing solar collectors, the reflective surface panel was modeled as a thin, initially flat, elastic plate that underwent large displacements to attain the shape of a prescribed parabolic cylinder. Attention was focused upon the stresses that developed in an adhesive layer which bonded the deformed panel to a rigid, parabolic substructure. Among the myriad possible collector designs, some possess longitudinally oriented, hollow ribs or corrugations in the substructure which interrupt the transverse continuity of the bond line between the deformed panel and the substructure. Thus, finite gaps in the adhesive are present which create regions where the panel surface becomes intermittently supported. The presence of these gaps perturbs the otherwise smooth distribution of adhesive contact stresses and it is the analytical modeling of this behavior that is the subject of the present report. In particular, attention is devoted to gaps which overlap with the edge effect zone - a region near the rim or vertex of the deformed panel where, in the absence of uniform edge loads necessary to maintain a true parabolic shape, high stresses and associated deformations occur. Significant influences of the gap size and position in the edge effect zone are demonstrated and discussed.

  3. Deformation of Diopside Single Crystal at Mantle Pressure 2 TEM Characterization of Deformation Microstructures

    SciTech Connect (OSTI)

    E Amiguet; P Cordier; P Raterron

    2011-12-31T23:59:59.000Z

    The dislocation microstructures of diopside single crystals deformed at high-pressure (4 {<=} P {<=} 9 GPa), high-temperature (1100{sup o} {<=} T {<=} 1400 {sup o}C) using a Deformation-DIA high-pressure apparatus (D-DIA) have been characterized by transmission electron microscopy using weak-beam dark-field (WBDF), precession electron diffraction (PED), large-angle convergent-beam electron diffraction (LACBED) and the thickness-fringe method. Dislocation glide is the dominant deformation mechanism under these conditions. The 1/2<110>{l_brace}110{r_brace} glide is controlled by lattice friction on the edge segments and shows extensive cross-slip. The [001] glide occurs mostly on {l_brace}110{r_brace}; no evidence for [001](010) glide has been found. The [100] dislocations bear a strong lattice friction probably due to complex (out of glide) core structures.

  4. Towards quantum noncommutative {kappa}-deformed field theory

    SciTech Connect (OSTI)

    Daszkiewicz, Marcin; Lukierski, Jerzy; Woronowicz, Mariusz [Institute of Theoretical Physics, University of Wroclaw pl. Maxa Borna 9, 50-206 Wroclaw (Poland)

    2008-05-15T23:59:59.000Z

    We introduce a new {kappa}-star product describing the multiplication of quantized {kappa}-deformed free fields. The {kappa} deformation of local free quantum fields originates from two sources: noncommutativity of space-time and the {kappa} deformation of field oscillators algebra; we relate these two deformations. We demonstrate that for a suitable choice of {kappa}-deformed field oscillators algebra, the {kappa}-deformed version of the microcausality condition is satisfied, and it leads to the deformation of the Pauli-Jordan commutation function defined by the {kappa}-deformed mass shell. We show by constructing the {kappa}-deformed Fock space that the use of the {kappa}-deformed oscillator algebra permits one to preserve the bosonic statistics of n-particle states. The proposed star product is extended to the product of n fields, which for n=4 defines the interaction vertex in perturbative description of the noncommutative quantum {lambda}{phi}{sup 4} field theory. It appears that the classical four-momentum conservation law is satisfied at the interaction vertices.

  5. IEEE TRANSACTIONS ON ROBOTICS, VOL. 22, NO. 4, AUGUST 2006 625 Path Planning for Deformable Linear Objects

    E-Print Network [OSTI]

    Moll, Mark

    --Deformation, differential geometry, flexible ma- nipulation, flexible object representation, minimal-energy curves, modeling with previous approaches. Using a simplified model for obstacles, we can find minimal-energy curves of fixed. These config- urations correspond to minimal-energy curves. By restricting the planner to minimal-energy curves

  6. Non-principal surface waves in deformed incompressible materials

    E-Print Network [OSTI]

    Michel Destrade; Melanie Ottenio; Alexey V. Pichugin; Graham A. Rogerson

    2013-04-23T23:59:59.000Z

    The Stroh formalism is applied to the analysis of infinitesimal surface wave propagation in a statically, finitely and homogeneously deformed isotropic half-space. The free surface is assumed to coincide with one of the principal planes of the primary strain, but a propagating surface wave is not restricted to a principal direction. A variant of Taziev's technique [Sov. Phys. Acoust. 35 (1989) 535] is used to obtain an explicit expression of the secular equation for the surface wave speed, which possesses no restrictions on the form of the strain energy function. Albeit powerful, this method does not produce a unique solution and additional checks are necessary. However, a class of materials is presented for which an exact secular equation for the surface wave speed can be formulated. This class includes the well-known Mooney-Rivlin model. The main results are illustrated with several numerical examples.

  7. Deformation of Equilibrium Shape of a Vesicle Induced by Injected Flexible Polymers

    E-Print Network [OSTI]

    Yutaka Oya; Katsuhiko Sato; Toshihiro Kawakatsu

    2010-11-17T23:59:59.000Z

    Using field theoretic approach, we study equilibrium shape deformation of a vesicle induced by the presence of enclosed flexible polymers, which is a simple model of drug delivery system or endocytosis. To evaluate the total free energy of this system, it is necessary to calculate the bending elastic energy of the membrane, the conformation entropy of the polymers and their interactions. For this purpose, we combine phase field theory for the membrane and self-consistent field theory for the polymers. Simulations on this coupled model system for axiosymmetric shapes show a shape deformation of the vesicle induced by introducing polymers into it. We examined the dependence of the stability of the vesicle shape on the chain length of the polymers and the packing ratio of the vesicle. We present a simple model calculation that shows the relative stability of the prolate shape compared to the oblate shape.

  8. A novel digital tomosynthesis (DTS) reconstruction method using a deformation field map

    SciTech Connect (OSTI)

    Ren Lei; Zhang Junan; Thongphiew, Danthai; Godfrey, Devon J.; Jackie Wu, Q.; Zhou Sumin; Yin Fangfang [Department of Radiation Oncology, Duke University Medical Center, DUMC Box 3295, Durham, North Carolina, 27710 (United States) and Duke Medical Physics Graduate Program, 2424 Erwin Road Suite 101, Durham, North Carolina 27705 (United States); Department of Radiation Oncology, Duke University Medical Center, DUMC Box 3295, Durham, North Carolina 27710 (United States); Department of Radiation Oncology, Duke University Medical Center, DUMC Box 3295, Durham, North Carolina, 27710 (United States) and Duke Medical Physics Graduate Program, 2424 Erwin Road Suite 101, Durham, North Carolina 27705 (United States)

    2008-07-15T23:59:59.000Z

    We developed a novel digital tomosynthesis (DTS) reconstruction method using a deformation field map to optimally estimate volumetric information in DTS images. The deformation field map is solved by using prior information, a deformation model, and new projection data. Patients' previous cone-beam CT (CBCT) or planning CT data are used as the prior information, and the new patient volume to be reconstructed is considered as a deformation of the prior patient volume. The deformation field is solved by minimizing bending energy and maintaining new projection data fidelity using a nonlinear conjugate gradient method. The new patient DTS volume is then obtained by deforming the prior patient CBCT or CT volume according to the solution to the deformation field. This method is novel because it is the first method to combine deformable registration with limited angle image reconstruction. The method was tested in 2D cases using simulated projections of a Shepp-Logan phantom, liver, and head-and-neck patient data. The accuracy of the reconstruction was evaluated by comparing both organ volume and pixel value differences between DTS and CBCT images. In the Shepp-Logan phantom study, the reconstructed pixel signal-to-noise ratio (PSNR) for the 60 deg. DTS image reached 34.3 dB. In the liver patient study, the relative error of the liver volume reconstructed using 60 deg. projections was 3.4%. The reconstructed PSNR for the 60 deg. DTS image reached 23.5 dB. In the head-and-neck patient study, the new method using 60 deg. projections was able to reconstruct the 8.1 deg. rotation of the bony structure with 0.0 deg. error. The reconstructed PSNR for the 60 deg. DTS image reached 24.2 dB. In summary, the new reconstruction method can optimally estimate the volumetric information in DTS images using 60 deg. projections. Preliminary validation of the algorithm showed that it is both technically and clinically feasible for image guidance in radiation therapy.

  9. Superplastic deformation in two microduplex stainless steels

    SciTech Connect (OSTI)

    Lesuer, D.R.; Nieh, T.G.; Syn, C.K. [Lawrence Livermore National Lab., CA (United States); Taleff, E.M. [Texas Univ., Austin, TX (United States)

    1996-09-01T23:59:59.000Z

    The deformation behavior and mechanisms of superplastic flow in two microduplex stainless steels (SuperDux64 and Nitronic 19D) were studied at {similar_to}0.7T{sub m}. The two steels differed in initial grain size by a factor of 3. Both steels exhibited solute-drag-controlled grain boundary sliding in a high temperature {gamma}+{delta} phase field. In a lower temperature {gamma}+{sigma} phase field, the fine-grained steel ({bar L}=5{mu}m) exhibited climb-controlled grain boundary sliding and the coarser- grained steel ({bar L}=15{mu}m) exhibited solute-drag-controlled slip creep.

  10. Kinetic bounding volume hierarchies for deformable objects

    E-Print Network [OSTI]

    Gabriel Zachmann; Tu Clausthal

    2006-01-01T23:59:59.000Z

    We present novel algorithms for updating bounding volume hierarchies of objects undergoing arbitrary deformations. Therefore, we introduce two new data structures, the kinetic AABB tree and the kinetic BoxTree. The event-based approach of the kinetic data structures framework enables us to show that our algorithms are optimal in the number of updates. Moreover, we show a lower bound for the total number of BV updates, which is independent of the number of frames. We used our kinetic bounding volume hierarchies for collision detection and performed a comparison with the classical bottomup update method. The results show that our algorithms perform up to ten times faster in practically relevant scenarios.

  11. EXAMINATION OF POSTIRRADIATION DEFORMATION MICROSTRUCTURES IN F82H

    SciTech Connect (OSTI)

    Gelles, David S.; Schaublin, R.

    2002-09-01T23:59:59.000Z

    The deformed microstructures of irradiated F82H uniaxial tensile specimens have been examined following irradiation in HFR to 2.6 dpa at 32 C in order to identify controlling mechanisms. Deformation following irradiation is found to occur in poorly defined channels, causing formation of discrete steps at surfaces, similar to that in unirradiated steel. Deformation is by motion of individual a/2<111> dislocations.

  12. Structure and deformation mechanisms along the Tonale Line, n. Italy

    E-Print Network [OSTI]

    Welker, Mary Clare

    1985-01-01T23:59:59.000Z

    of Advisory Committee: John M. Logan Field observations and sampling are combined with petrofabric and fracture analyses to characterize the structure and deformation mechanisms related to a segment of the Tonale Line fault zone in northern Italy. Mylonite... microstructures and fabrics are developed superimposed by cataclasites and fault gouge; the latter being character istic of deformation at shallow depths. The ductile deformation associated with faulting along the Tonale Line occurred under greenschist...

  13. Deformed relativistic and nonrelativistic symmetries on canonical noncommutative spaces

    SciTech Connect (OSTI)

    Banerjee, Rabin; Kumar, Kuldeep [S.N. Bose National Centre for Basic Sciences, JD Block, Sector 3, Salt Lake, Kolkata 700098 (India); Department of Physics, Panjab University, Chandigarh 160014 (India)

    2007-02-15T23:59:59.000Z

    We study the general deformed conformal-Poincare (Galilean) symmetries consistent with relativistic (nonrelativistic) canonical noncommutative spaces. In either case we obtain deformed generators, containing arbitrary free parameters, which close to yield new algebraic structures. We show that a particular choice of these parameters reproduces the undeformed algebra. The modified coproduct rules and the associated Hopf algebra are also obtained. Finally, we show that for the choice of parameters leading to the undeformed algebra, the deformations are represented by twist functions.

  14. A method to estimate the effect of deformable image registration uncertainties on daily dose mapping

    SciTech Connect (OSTI)

    Murphy, Martin J.; Salguero, Francisco J.; Siebers, Jeffrey V.; Staub, David; Vaman, Constantin [Department of Radiation Oncology, Virginia Commonwealth University, Richmond Virginia 23298 (United States)

    2012-02-15T23:59:59.000Z

    Purpose: To develop a statistical sampling procedure for spatially-correlated uncertainties in deformable image registration and then use it to demonstrate their effect on daily dose mapping. Methods: Sequential daily CT studies are acquired to map anatomical variations prior to fractionated external beam radiotherapy. The CTs are deformably registered to the planning CT to obtain displacement vector fields (DVFs). The DVFs are used to accumulate the dose delivered each day onto the planning CT. Each DVF has spatially-correlated uncertainties associated with it. Principal components analysis (PCA) is applied to measured DVF error maps to produce decorrelated principal component modes of the errors. The modes are sampled independently and reconstructed to produce synthetic registration error maps. The synthetic error maps are convolved with dose mapped via deformable registration to model the resulting uncertainty in the dose mapping. The results are compared to the dose mapping uncertainty that would result from uncorrelated DVF errors that vary randomly from voxel to voxel. Results: The error sampling method is shown to produce synthetic DVF error maps that are statistically indistinguishable from the observed error maps. Spatially-correlated DVF uncertainties modeled by our procedure produce patterns of dose mapping error that are different from that due to randomly distributed uncertainties. Conclusions: Deformable image registration uncertainties have complex spatial distributions. The authors have developed and tested a method to decorrelate the spatial uncertainties and make statistical samples of highly correlated error maps. The sample error maps can be used to investigate the effect of DVF uncertainties on daily dose mapping via deformable image registration. An initial demonstration of this methodology shows that dose mapping uncertainties can be sensitive to spatial patterns in the DVF uncertainties.

  15. Deformed bubble growth and coalescence in polymer foam processing

    E-Print Network [OSTI]

    Allaboun, Hussein Raji

    1996-01-01T23:59:59.000Z

    conditions (Table 34 0. 1 Viacoelaatic ? ? ? - - Newtoruan o. os V 2 10 4 10 6 10 8 10 1 10 1. 2 10 Time, 1* Figure 4. 1. The viscous limit of the viscoelastic melt. 35 0. 035 0. 03 0. 025 O. O2 0. 015 O. O1 - ti/90 =o. s ? ti/tl. =o. 75 q/q... q/q q/q, 0. 005 1O' 1O' 102 Time, 1* 10' 104 Figure 4. Effect of viscosity on bubble pressure. An increase in the viscosity resulted in a decrease of the rate of change of gaseous phase pressure ( See Figure 4. 2), and, consequently...

  16. ankle deformity secondary: Topics by E-print Network

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

    in the Trapezium Cluster: First Scientific Results from the MMT Deformable Secondary Mirror Adaptive Optics System Astrophysics (arXiv) Summary: We present the first scientific...

  17. Free motion in deformed (quantum) four-dimensional space

    E-Print Network [OSTI]

    A. N. Leznov

    2007-07-23T23:59:59.000Z

    It is shown that trajectories of free motion of the particles in deformed ("quantum") four dimensional space-time are quadratic curves.

  18. Contemporary Tectonic Deformation of the Basin and Range Province...

    Open Energy Info (EERE)

    Belt lithosphere is rheologically weak. However, we show that linear gradients in viscosity and gravitational potential energy can also effectively concentrate deformation. In...

  19. Deformation and seismicity in the Coso geothermal area, Inyo...

    Open Energy Info (EERE)

    interferometry Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Deformation and seismicity in the Coso geothermal area, Inyo County,...

  20. FINAL REPORT Grothendieck-Teichmller Groups, Deformation and

    E-Print Network [OSTI]

    FINAL REPORT Grothendieck-Teichmüller Groups, Deformation and Operads [GDO programme] January (Nice) and Nick Woodhouse (CMI). Programme Partner: Clay Mathematics Institute. State of the art

  1. In-situ Phase Transformation and Deformation of Iron at High Pressure andTemperature

    SciTech Connect (OSTI)

    Miyagi, Lowell; Kunz, Martin; Knight, Jason; Nasiatka, James; Voltolini, Marco; Wenk, Hans-Rudolf

    2008-07-01T23:59:59.000Z

    With a membrane based mechanism to allow for pressure change of a sample in aradial diffraction diamond anvil cell (rDAC) and simultaneous infra-red laser heating, itis now possible to investigate texture changes during deformation and phasetransformations over a wide range of temperature-pressure conditions. The device isused to study bcc (alpha), fcc (gamma) and hcp (epislon) iron. In bcc iron, room temperature compression generates a texture characterized by (100) and (111) poles parallel to the compression direction. During the deformation induced phase transformation to hcp iron, a subset of orientations are favored to transform to the hcp structure first and generate a texture of (01-10) at high angles to the compression direction. Upon further deformation, the remaining grains transform, resulting in a texture that obeys the Burgers relationship of (110)bcc // (0001)hcp. This is in contrast to high temperature results that indicate that texture is developed through dominant pyramidal {2-1-12}<2-1-13> and basal (0001)-{2-1-10} slip based on polycrystal plasticity modeling. We also observe that the high temperature fcc phase develops a 110 texture typical for fcc metals deformed in compression.

  2. Inflation and deformation of conformal field theory

    SciTech Connect (OSTI)

    Garriga, Jaume; Urakawa, Yuko, E-mail: jaume.garriga@ub.edu, E-mail: yurakawa@ffn.ub.es [Departament de Física Fonamental i Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain)

    2013-07-01T23:59:59.000Z

    It has recently been suggested that a strongly coupled phase of inflation may be described holographically in terms of a weakly coupled quantum field theory (QFT). Here, we explore the possibility that the wave function of an inflationary universe may be given by the partition function of a boundary QFT. We consider the case when the field theory is a small deformation of a conformal field theory (CFT), by the addition of a relevant operator O, and calculate the primordial spectrum predicted in the corresponding holographic inflation scenario. Using the Ward-Takahashi identity associated with Weyl rescalings, we derive a simple relation between correlators of the curvature perturbation ? and correlators of the deformation operator O at the boundary. This is done without specifying the bulk theory of gravitation, so that the result would also apply to cases where the bulk dynamics is strongly coupled. We comment on the validity of the Suyama-Yamaguchi inequality, relating the bi-spectrum and tri-spectrum of the curvature perturbation.

  3. The role of electron-screening deformations in solar nuclear fusion reactions and the solar neutrino puzzle

    E-Print Network [OSTI]

    Theodore E. Liolios

    2000-08-13T23:59:59.000Z

    Thermonuclear fusion reaction rates in the solar plasma are enhanced by the presence of the electron cloud that screens fusing nuclei. The present work studies the influence of electron screening deformations on solar reaction rates in the framework of the Debye-Huckel model. These electron-ion cloud deformations, assumed here to be static and axially symmetric, are shown to be able to considerably influence the solar neutrino fluxes of the pp and the CNO chains, with reasonable changes in the macroscopic parameters of the standard solar model (SSM) . Various known deformation sources are discussed but none of them is found strong enough to have a significant impact on the SSM neutrino fluxes.

  4. Interactive modeler for cloth draping

    E-Print Network [OSTI]

    Thumrugoti, Umakanth

    1994-01-01T23:59:59.000Z

    2. Bezier Curves . 3. Hyperpatches. . . B. Deformation 1. Free Form Deformation (FFD) 2. Extended Free Form Deformation (EFFD) . C. Overview of the Model 1. Lattice 2. Newton ? Raphson Method . 3. LU Decomposition . 4. Newell's Method... 14 14 15 20 25 25 29 30 30 33 35 37 38 39 39 40 41 46 46 51 54 Page REFERENCES . APPENDIX A A. Menubar B. Lattice Buttons VITA 59 59 59 vn LIST OF FIGURES FIGURE Page Parallelepipedical 3D lattice A Bezier curve...

  5. Type-IV Pilus Deformation Can Explain Retraction Behavior

    E-Print Network [OSTI]

    Ranajay Ghosh; Aloke Kumar; Ashkan Vaziri

    2014-09-18T23:59:59.000Z

    Polymeric filament like type IV Pilus (TFP) can transfer forces in excess of 100pN during their retraction before stalling, powering surface translocation(twitching). Single TFP level experiments have shown remarkable nonlinearity in the retraction behavior influenced by the external load as well as levels of PilT molecular motor protein. This includes reversal of motion near stall forces when the concentration of the PilT protein is lowered significantly. In order to explain this behavior, we analyze the coupling of TFP elasticity and interfacial behavior with PilT kinetics. We model retraction as reaction controlled and elongation as transport controlled process. The reaction rates vary with TFP deformation which is modeled as a compound elastic body consisting of multiple helical strands under axial load. Elongation is controlled by monomer transport which suffer entrapment due to excess PilT in the cell periplasm. Our analysis shows excellent agreement with a host of experimental observations and we present a possible biophysical relevance of model parameters through a mechano-chemical stall force map

  6. Plastic deformation in Al (Cu) interconnects stressed by electromigration and studied by synchrotron polychromatic X-ray microdiffraction

    E-Print Network [OSTI]

    Chen, Kai; Advanced Light Source; UCLA

    2008-01-01T23:59:59.000Z

    Plastic deformation in Al (Cu) interconnects stressed bygrain orientation [7], study plastic deformation [12-15] andThis aspect of EM-induced plastic deformation in grains

  7. Cortical Hemisphere Registration Via Large Deformation Diffeomorphic Metric Curve

    E-Print Network [OSTI]

    Qiu, Anqi

    on the relation between individual brains and the atlas. This is a powerful approach allowing us to study a largeCortical Hemisphere Registration Via Large Deformation Diffeomorphic Metric Curve Mapping Anqi Qiu1 Science, Johns Hopkins University Abstract. We present large deformation diffeomorphic metric curve

  8. Micrographic detection of plastic deformation in nickel base alloys

    DOE Patents [OSTI]

    Steeves, Arthur F. (Schenectady, NY); Bibb, Albert E. (Clifton Park, NY)

    1984-01-01T23:59:59.000Z

    A method for detecting low levels of plastic deformation in metal articles comprising electrolytically etching a flow free surface of the metal article with nital at a current density of less than about 0.1 amp/cm.sup.2 and microscopically examining the etched surface to determine the presence of alternating striations. The presence of striations indicates plastic deformation in the article.

  9. Granite ascent and emplacement during contractional deformation in convergent orogens

    E-Print Network [OSTI]

    Solar, Gary S.

    Granite ascent and emplacement during contractional deformation in convergent orogens MICHAEL BROWN of granite melt through the crust in convergent orogens. During contractional deformation, ¯ow of melt to weakly discordant irregular granite sheets occur in zones of higher strain, which suggests percolative

  10. On the thermomechanical deformation of silver shape memory nanowires

    E-Print Network [OSTI]

    Lin, Xi

    On the thermomechanical deformation of silver shape memory nanowires Harold S. Park *, Changjiang an analysis of the uniaxial thermomechanical deformation of single-crystal silver shape memory nanowires using atomistic simulations. We first demonstrate that silver nanowires can show both shape memory

  11. Medially Based Meshing with Finite Element Analysis of Prostate Deformation

    E-Print Network [OSTI]

    Crouch, Jessica R.

    Medially Based Meshing with Finite Element Analysis of Prostate Deformation Jessica R. Crouch1 have approached prostate imaging problems using meth- ods that incorporate finite element analysis. Assume the prostate is a linearly elastic body and compute its deformation using finite element analysis

  12. Deformations of Quantum Symmetric Algebras Extended by Groups

    E-Print Network [OSTI]

    Shakalli Tang, Jeanette

    2012-07-16T23:59:59.000Z

    The study of deformations of an algebra has been a topic of interest for quite some time, since it allows us to not only produce new algebras but also better understand the original algebra. Given an algebra, finding all its deformations is...

  13. Tetrahedral Mesh Generation for Deformable Bodies Neil Molino

    E-Print Network [OSTI]

    Stanford University

    , the finite element method or an optimization approach to relax the positions of both the interior refinement, finite element method, level set methods 1 Introduction Tetrahedral meshes are used in a number for fluid flow and heat transfer where the mesh is not deformed, and for small deformation solids where

  14. Neutron shell structure and deformation in neutron-drip-line nuclei

    E-Print Network [OSTI]

    Ikuko Hamamoto

    2012-06-18T23:59:59.000Z

    Neutron shell-structure and the resulting possible deformation in the neighborhood of neutron-drip-line nuclei are systematically discussed, based on both bound and resonant neutron one-particle energies obtained from spherical and deformed Woods-Saxon potentials. Due to the unique behavior of weakly-bound and resonant neutron one-particle levels with smaller orbital angular-momenta $\\ell$, a systematic change of the shell structure and thereby the change of neutron magic-numbers are pointed out, compared with those of stable nuclei expected from the conventional j-j shell-model. For spherical shape with the operator of the spin-orbit potential conventionally used, the $\\ell_{j}$ levels belonging to a given oscillator major shell with parallel spin- and orbital-angular-momenta tend to gather together in the energetically lower half of the major shell, while those levels with anti-parallel spin- and orbital-angular-momenta gather in the upper half. The tendency leads to a unique shell structure and possible deformation when neutrons start to occupy the orbits in the lower half of the major shell. Among others, the neutron magic-number N=28 disappears and N=50 may disappear, while the magic number N=82 may presumably survive due to the large $\\ell =5$ spin-orbit splitting for the $1h_{11/2}$ orbit. On the other hand, an appreciable amount of energy gap may appear at N=16 and 40 for spherical shape, while neutron-drip-line nuclei in the region of neutron number above N=20, 40 and 82, namely N $\\approx$ 21-28, N $\\approx$ 41-54, and N $\\approx$ 83-90, may be quadrupole-deformed though the possible deformation depends also on the proton number of respective nuclei.

  15. High stroke pixel for a deformable mirror

    DOE Patents [OSTI]

    Miles, Robin R.; Papavasiliou, Alexandros P.

    2005-09-20T23:59:59.000Z

    A mirror pixel that can be fabricated using standard MEMS methods for a deformable mirror. The pixel is electrostatically actuated and is capable of the high deflections needed for spaced-based mirror applications. In one embodiment, the mirror comprises three layers, a top or mirror layer, a middle layer which consists of flexures, and a comb drive layer, with the flexures of the middle layer attached to the mirror layer and to the comb drive layer. The comb drives are attached to a frame via spring flexures. A number of these mirror pixels can be used to construct a large mirror assembly. The actuator for the mirror pixel may be configured as a crenellated beam with one end fixedly secured, or configured as a scissor jack. The mirror pixels may be used in various applications requiring high stroke adaptive optics.

  16. Reversibility of Red blood Cell deformation

    E-Print Network [OSTI]

    Maria Zeitz; Pierre Sens

    2011-11-22T23:59:59.000Z

    The ability of cells to undergo reversible shape changes is often crucial to their survival. For Red Blood Cells (RBCs), irreversible alteration of the cell shape and flexibility often causes anemia. Here we show theoretically that RBCs may react irreversibly to mechanical perturbations because of tensile stress in their cytoskeleton. The transient polymerization of protein fibers inside the cell seen in sickle cell anemia or a transient external force can trigger the formation of a cytoskeleton-free membrane protrusion of micrometer dimensions. The complex relaxation kinetics of the cell shape is shown to be responsible for selecting the final state once the perturbation is removed, thereby controlling the reversibility of the deformation. In some case, tubular protrusion are expected to relax via a peculiar "pearling instability".

  17. Interfacial deformation and jetting of a magnetic fluid

    E-Print Network [OSTI]

    Afkhami, Shahriar; Griffiths, Ian M

    2015-01-01T23:59:59.000Z

    An attractive technique for forming and collecting aggregates of magnetic material at a liquid--air interface by an applied magnetic field gradient was recently addressed theoretically and experimentally [Soft Matter, (9) 2013, 8600-8608]: when the magnetic field is weak, the deflection of the liquid--air interface has a steady shape, while for sufficiently strong fields, the interface destabilizes and forms a jet that extracts magnetic material. Motivated by this work, we develop a numerical model for the closely related problem of solving two-phase Navier--Stokes equations coupled with the static Maxwell equations. We computationally model the forces generated by a magnetic field gradient produced by a permanent magnet and so determine the interfacial deflection of a magnetic fluid (a pure ferrofluid system) and the transition into a jet. We analyze the shape of the liquid--air interface during the deformation stage and the critical magnet distance for which the static interface transitions into a jet. We d...

  18. Jet Riemann-Hamilton geometrization for the conformal deformed Berwald-Moor quartic metric depending on momenta

    E-Print Network [OSTI]

    Alexandru Oana; Mircea Neagu

    2012-05-03T23:59:59.000Z

    In this paper we expose on the dual 1-jet space J^{1*}(R,M^4) the distinguished (d-) Riemannian geometry (in the sense of d-connection, d-torsions, d-curvatures and some gravitational-like and electromagnetic-like geometrical models) for the (t,x)-conformal deformed Berwald-Moor Hamiltonian metric of order four.

  19. Asphalt Pavement Aging and Temperature Dependent Properties through a Functionally Graded Viscoelastic Model, Part-I: Development,

    E-Print Network [OSTI]

    Paulino, Glaucio H.

    Asphalt Pavement Aging and Temperature Dependent Properties through a Functionally Graded simulations, correspondence principle, finite-element method Abstract. Asphalt concrete pavements to climatic conditions are the major cause of such graded non-homogeneity. Current pavement analysis

  20. EFFECT OF GRAIN SIZE ON THE ACOUSTIC EMISSION GENERATED DURING PLASTIC DEFORMATION OF ALUMINUM

    E-Print Network [OSTI]

    Baram, J.

    2013-01-01T23:59:59.000Z

    PLASTIC DEFORMATION OF ALUMINUM LAWRENCE BERKELEY LABORATORYDURING PLASTIC DEFORMATION OF ALUMINUM J. Baram Materialsof polycrystalline aluminum, of different grain sizes and at

  1. Perspectives on the viscoelasticity and flow behavior of entangled linear and branched polymers

    E-Print Network [OSTI]

    Snijkers, F; Olmsted, P D; Vlassopoulos, D

    2015-01-01T23:59:59.000Z

    We briefly review the recent advances in the rheology of entangled polymers and identify emerging research trends and outstanding challenges, especially with respect to branched polymers. Emphasis is placed on the role of well-characterized model systems, as well as the synergy of synthesis-characterization, rheometry and modeling/simulations. The theoretical framework for understanding the observed linear and nonlinear rheological phenomena is the tube model which is critically assessed in view of its successes and shortcomings, whereas alternative approaches are briefly discussed. Finally, intriguing experimental findings and controversial issues that merit consistent explanation, such as shear banding instabilities, multiple stress overshoots in transient simple shear and enhanced steady-state elongational viscosity in polymer solutions, are discussed, whereas future directions such as branch point dynamics and anisotropic monomeric friction are outlined.

  2. Computational Issues in Fitting Spatial Deformation Models for Heterogeneous

    E-Print Network [OSTI]

    Washington at Seattle, University of

    in the correlation structure however. For example, there may be pollutant sources that impact a small geo- graphic be irregularly located in space. Suppose that Z xi;t represent the data that result from standardization by the

  3. Time-critical collision handling for deformable modeling

    E-Print Network [OSTI]

    Teschner, Matthias

    or surgical simula- tors, where a pre-defined response time should be guaranteed for each simulation step. We- quent simulation step. If an exact response can- not be computed in a given time frame, the algo- rithm forces. Detection, penetration depth estimation and response are di- vided into atomic tasks. In case

  4. Coupling Deformable Models for Multi-Object Segmentation

    E-Print Network [OSTI]

    Andrzejak, Artur

    for regions on a femoral head and acetabulum and other adjacent structures, as well as prelimi- nary in these cases, knowledge about adjacent structures must be exploited. Op- timal graph searching based, in joint regions, thresholding is often not sufficient for separating adjacent individual bones from each

  5. Continuum models of deformation mechanisms in nanocrystalline metals

    E-Print Network [OSTI]

    Jérusalem, Antoine, 1979-

    2007-01-01T23:59:59.000Z

    Nanocrystalline metals are polycrystalline metals with grain sizes in the nanometer range. They have attracted significant interest in recent years due to their unique mechanical and electrical properties. The main objective ...

  6. Segmentation-aware Deformable Part Models Eduard Trulls1

    E-Print Network [OSTI]

    Moreno-Noguer, Francesc

    (a), and a set of SLIC superpixels at different scales (b)--we show two scales. We pick the superpix

  7. Modeling Of Surface Deformation From Satellite Radar Interferometry In The

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere I Geothermal Pwer Plant JumpMarysville,Missoula, Montana: EnergyAnalysis of Energy Demand (MAED-2) JumpSalton

  8. Thermoplastic deformation of silicon surfaces induced by ultrashort pulsed lasers in submelting conditions

    SciTech Connect (OSTI)

    Tsibidis, G. D. [Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology (FORTH), N. Plastira 100, Vassilika Vouton, 70013, Heraklion, Crete (Greece); Stratakis, E. [Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology (FORTH), N. Plastira 100, Vassilika Vouton, 70013, Heraklion, Crete (Greece); Department of Materials Science and Technology, University of Crete, 710 03 Heraklion, Crete (Greece); Aifantis, K. E. [Laboratory of Mechanics and Materials, Aristotle University of Thessaloniki, GR-54006 Thessaloniki (Greece)

    2012-03-01T23:59:59.000Z

    A hybrid theoretical model is presented to describe thermoplastic deformation effects on silicon surfaces induced by single and multiple ultrashort pulsed laser irradiation in submelting conditions. An approximation of the Boltzmann transport equation is adopted to describe the laser irradiation process. The evolution of the induced deformation field is described initially by adopting the differential equations of dynamic thermoelasticity while the onset of plastic yielding is described by the von Mises stress. Details of the resulting picometre sized crater, produced by irradiation with a single pulse, are discussed as a function of the imposed conditions and thresholds for the onset of plasticity are computed. Irradiation with multiple pulses leads to ripple formation of nanometre size that originates from the interference of the incident and a surface scattered wave. It is suggested that ultrafast laser induced surface modification in semiconductors is feasible in submelting conditions, and it may act as a precursor of the incubation effects observed at multiple pulse irradiation of materials surfaces.

  9. Neutrinoless double beta decay of $^{150}$Nd with account for deformation

    E-Print Network [OSTI]

    Dong-Liang Fang; Amand Faessler; Vadim Rodin; Fedor Simkovic

    2010-11-02T23:59:59.000Z

    A microscopic state-of-the-art calculation of the nuclear matrix element for neutrinoless double beta decay of $^{150}$Nd with an account for nuclear deformation is performed. The proton-neutron quasiparticle random phase approximation (QRPA) with a realistic residual interaction [the Brueckner $G$ matrix derived from the charge-depending Bonn (Bonn-CD) nucleon-nucleon potential] is used as the underlying nuclear structure model. The present calculated matrix element is suppressed by about 40% as compared with our previous QRPA result for $^{150}$Nd obtained with neglect of deformation. By making use of this newest nuclear matrix element, one may conclude that neutrinoless double beta decay of $^{150}$Nd, to be measured soon by the SNO+ collaboration, provides one of the best probes of the Majorana neutrino mass.

  10. Neutrinoless double-{beta} decay of {sup 150}Nd accounting for deformation

    SciTech Connect (OSTI)

    Fang Dongliang; Faessler, Amand; Rodin, Vadim; Simkovic, Fedor [Institut fuer Theoretische Physik, Universitaet Tuebingen, D-72076 Tuebingen (Germany); BLTP, JINR, Dubna (Russian Federation) and Department of Nuclear Physics, Comenius University, SK-842 15 Bratislava (Slovakia)

    2010-11-15T23:59:59.000Z

    A microscopic state-of-the-art calculation of the nuclear matrix element for neutrinoless double-{beta} decay of {sup 150}Nd with an account for nuclear deformation is performed. The proton-neutron quasiparticle random phase approximation (QRPA) with a realistic residual interaction [the Brueckner G matrix derived from the charge-dependent Bonn (Bonn-CD) nucleon-nucleon potential] is used as the underlying nuclear structure model. The present calculated matrix element is suppressed by about 40% as compared with our previous QRPA result for {sup 150}Nd obtained with neglect of deformation. By making use of this newest nuclear matrix element, one may conclude that neutrinoless double-{beta} decay of {sup 150}Nd, to be measured soon by the SNO+ collaboration, provides one of the best probes of the Majorana neutrino mass.

  11. Numerical study of viscoelastic mixtures through a Cahn-Hilliard Franck Boyer1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -time numerical simulations. Several significant tests (channel under shear, filling of tanks, breakup of jets. In this model, the sharp interface is replaced by a narrow transition layer across which the fluids may mix to describe the concentration of one of the fluids in the mixture. The resulting system of equations couples

  12. Non-linear viscoelastic response of magnetic fiber suspensions in oscillatory shear P. Kuzhira*

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    of 37 µm and diameter of 4.9 µm, dispersed in a silicon oil. Rheological measurements have been carried showed a high-frequency plateau, typical for Maxwell behavior. Our simple single relaxation time model. The magnetic fiber suspensions have shown better sedimentation stability [4

  13. DYNAMIC, TRANSIENT, MODE I CRACK PROPAGATION WITH A NONLINEAR, VISCOELASTIC COHESIVE ZONE

    E-Print Network [OSTI]

    Gorb, Yuliya

    simplifying idealizations, presents many technical obstacles. In general, polymeric materials exhibit complex. The specific forms for the time dependent cohesive zone models studied below were derived through accelerating mode I cracks in elastic material but do not explicitly exhibit a full solution for general

  14. New version of $q$-deformed supersymmetric quantum mechanics

    E-Print Network [OSTI]

    Gavrilik, A M; Lukash, A V

    2013-01-01T23:59:59.000Z

    A new version of the q-deformed supersymmetric quantum mechanics (q-SQM), which is inspired by the Tamm--Dankoff-type (TD-type) deformation of quantum harmonic oscillator, is constructed. The obtained algebra of q-SQM is similar to that in Spiridonov's approach. However, within our version of q-SQM, the ground state found explicitly in the special case of superpotential yiealding q-superoscillator turns out to be non-Gaussian and takes the form of special (TD-type) q-deformed Gaussian.

  15. Deformation twinning mechanisms in FCC and HCP metals

    SciTech Connect (OSTI)

    Wang, Jian [Los Alamos National Laboratory; Tome, Carlos N [Los Alamos National Laboratory; Beyerlein, Irene J [Los Alamos National Laboratory; Misra, Amit [Los Alamos National Laboratory; Mara, N [Los Alamos National Laboratory

    2011-01-31T23:59:59.000Z

    We report the recent work on twinning and detwinning in fcc and hcp metals based on the in situ and ex situ TEM observations and molecular dynamics simulations. Three aspects are discussed in this paper. (1) Detwinning in single-phase Cu with respect to growth twins, (2) deformation twinning in Ag-Cu composites, and (3) deformation twinning mechanisms in hcp metals. The main conclusion is that atomic structures of interfaces (twin boundaries, two-phases interface, and grain boundaries) play a crucial role in nucleating and propagating of deformation twins.

  16. q-Deformed Boson Oscillators and Zero Point Energy

    E-Print Network [OSTI]

    P. Narayana Swamy

    1999-09-22T23:59:59.000Z

    Just as for the ordinary quantum harmonic oscillators, we expect the zero-point energy to play a crucial role in the correct high temperature behavior. We accordingly reformulate the theory of the statistical distribution function for the q-deformed boson oscillators and develop an approximate theory incorporating the zero-point energy. We are then able to demonstrate that for small deformations, the theory reproduces the correct limits both for very high temperatures and for very low temperatures. The deformed theory thus reduces to the undeformed theory in these extreme cases.

  17. Emergent noncommutative gravity from a consistent deformation of gauge theory

    SciTech Connect (OSTI)

    Cortese, Ignacio; Garcia, J Antonio [Departamento de Fisica de Altas Energias, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico D. F. 04510 (Mexico)

    2010-05-15T23:59:59.000Z

    Starting from a standard noncommutative gauge theory and using the Seiberg-Witten map, we propose a new version of a noncommutative gravity. We use consistent deformation theory starting from a free gauge action and gauging a killing symmetry of the background metric to construct a deformation of the gauge theory that we can relate with gravity. The result of this consistent deformation of the gauge theory is nonpolynomial in A{sub {mu}.} From here we can construct a version of noncommutative gravity that is simpler than previous attempts. Our proposal is consistent and is not plagued with the problems of other approaches like twist symmetries or gauging other groups.

  18. DEFORMATION-BASED NONLINEAR DIMENSION REDUCTION: APPLICATIONS TO NUCLEAR MORPHOMETRY

    E-Print Network [OSTI]

    Gordon, Geoffrey J.

    DEFORMATION-BASED NONLINEAR DIMENSION REDUCTION: APPLICATIONS TO NUCLEAR MORPHOMETRY Gustavo K, contrary to common intuition, the most likely nuclear shape configuration is not symmetric. Index Terms-- Nuclear shape analysis, nonlinear, dimension reduction, image registration. 1. INTRODUCTION Under

  19. Overprinting Deformations in Mantle Rocks, Dun Mountain, New Zealand

    E-Print Network [OSTI]

    Donnelly, Sara

    2014-04-25T23:59:59.000Z

    accommodated deformation (Goetze and Kohlstedt, 1973; Drury and Urai, 1990; Passchier and Trouw, 2005). Intermediate and fine grain size populations formed as a result of recrystallization-accommodated dislocation creep that overprinted, or partially...

  20. Experimental Study on Rock Deformation and Permeability Variation

    E-Print Network [OSTI]

    Ding, Jihui

    2013-08-01T23:59:59.000Z

    The development of a petroleum reservoir would inevitably induce a rearrangement of the in-situ stress field. The rearrangement of the stress field would then bring about a deformation of the reservoir rock and a change of the permeability...

  1. Self-sorting of deformable particles in a microfluidic circuit

    E-Print Network [OSTI]

    Raafat, Mohamed Salem

    2010-01-01T23:59:59.000Z

    In this thesis, a new microfluidic device is presented for sorting of deformable particles based on the hydrodynamic resistance induced in a microchannel. Hydrodynamic resistance can be related to physical properties, ...

  2. antebrachial growth deformity: Topics by E-print Network

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

    boost generator as the corner transfer matrix is briefly discussed. Cesar Gomez; Rafael Hernandez 2007-03-23 35 Deformation in Phase Space Mathematical Physics (arXiv) Summary:...

  3. 3D deformation field throughout the interior of materials.

    SciTech Connect (OSTI)

    Jin, Huiqing; Lu, Wei-Yang

    2013-09-01T23:59:59.000Z

    This report contains the one-year feasibility study for our three-year LDRD proposal that is aimed to develop an experimental technique to measure the 3D deformation fields inside a material body. In this feasibility study, we first apply Digital Volume Correlation (DVC) algorithm to pre-existing in-situ Xray Computed Tomography (XCT) image sets with pure rigid body translation. The calculated displacement field has very large random errors and low precision that are unacceptable. Then we enhance these tomography images by setting threshold of the intensity of each slice. DVC algorithm is able to obtain accurate deformation fields from these enhanced image sets and the deformation fields are consistent with the global mechanical loading that is applied to the specimen. Through this study, we prove that the internal markers inside the pre-existing tomography images of aluminum alloy can be enhanced and are suitable for DVC to calculate the deformation field throughout the material body.

  4. anomalously large deformation: Topics by E-print Network

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

    radiation. I. F. Malov 2007-11-04 88 A study of large plastic deformations in dual phase steel using digital image correlation and FE analysis Physics Websites Summary: ),...

  5. Activation of conductive pathways via deformation-induced instabilities

    E-Print Network [OSTI]

    Ni, Xinchen

    2014-01-01T23:59:59.000Z

    Inspired by the pattern transformation of periodic elastomeric cellular structures, the purpose of this work is to exploit this unique ability to activate conductive via deformation-induced instabilities. Two microstructural ...

  6. ORIGINAL ARTICLE LEGO-like assembly of peelable, deformable

    E-Print Network [OSTI]

    Rogers, John A.

    to the production of an integrated architecture without additional electrical connections. The free technologies that can release mechanical stress has enabled the production of various electronic circuits on non-conven- tional, deformable substrates including plastic, elastomeric rubber, fabric, paper

  7. Minor Groove Deformability of DNA: A Molecular Dynamics Free...

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

    experimental DNA structures in complex with minor groove-binding proteins. The calculated free energy of minor groove deformation was 4–6 kcal mol-1 in the case of a central...

  8. Fabrication of amorphous metal matrix composites by severe plastic deformation 

    E-Print Network [OSTI]

    Mathaudhu, Suveen Nigel

    2006-10-30T23:59:59.000Z

    Bulk metallic glasses (BMGs) have displayed impressive mechanical properties, but the use and dimensions of material have been limited due to critical cooling rate requirements and low ductility. The application of severe plastic deformation...

  9. Numerical Modeling of Fracture Permeability Change in Naturally Fractured Reservoirs Using a Fully Coupled Displacement Discontinuity Method.

    E-Print Network [OSTI]

    Tao, Qingfeng

    2010-07-14T23:59:59.000Z

    finite difference method to solve the fluid flow in fractures, a fully coupled displacement discontinuity method to build the global relation of fracture deformation, and the Barton-Bandis model of fracture deformation to build the local relation...

  10. Experimental deformation of multilithologic specimens simulating sedimentary facies changes 

    E-Print Network [OSTI]

    Dyke, Lawrence Dana

    1976-01-01T23:59:59.000Z

    EXPERIMENTAL DEFORMATION OF MULTILITHOLOGIC SPECIMENS SIMULATING SEDIMENTARY FACIES CHANGES A Thesis by LAWRENCE DANA DYKE Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1976 Major Subject: Geology EXPERIMENTAL DEFORMATION OF MULTILITHOLOGIC SPECIMENS SIMULATING SEDIMENTARY FACIES CHANGES A Thesis by LAWRENCE DANA DYKE Approved as to style and content by: (Chai n Committee) (Head...

  11. TDHF fusion calculations for spherical+deformed systems

    E-Print Network [OSTI]

    A. S. Umar; V. E. Oberacker

    2006-04-04T23:59:59.000Z

    We outline a formalism to carry out TDHF calculations of fusion cross sections for spherical + deformed nuclei. The procedure incorporates the dynamic alignment of the deformed nucleus into the calculation of the fusion cross section. The alignment results from multiple E2/E4 Coulomb excitation of the ground state rotational band. Implications for TDHF fusion calculations are discussed. TDHF calculations are done in an unrestricted three-dimensional geometry using modern Skyrme force parametrizations.

  12. Effect of nuclear deformation on double beta decay

    SciTech Connect (OSTI)

    Rodin, Vadim [Institute fuer Theoretische Physik der Universitaet Tuebingen, D-72076 Tuebingen (Germany)

    2009-11-09T23:59:59.000Z

    The existing ways of accounting for deformation in recent calculations of neutrinoless double beta decay matrix elements are discussed. From an analysis of relevant experimental data it is argued that only {sup 150}Nd reveals convincing evidences of strong static deformation, which should eventually be taken into account in QRPA calculations. A proposal which allows in principle to measure the neutrino less double beta decay Fermi matrix element is briefly described.

  13. Experimental deformation of multilithologic specimens simulating sedimentary facies changes

    E-Print Network [OSTI]

    Dyke, Lawrence Dana

    1976-01-01T23:59:59.000Z

    EXPERIMENTAL DEFORMATION OF MULTILITHOLOGIC SPECIMENS SIMULATING SEDIMENTARY FACIES CHANGES A Thesis by LAWRENCE DANA DYKE Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1976 Major Subject: Geology EXPERIMENTAL DEFORMATION OF MULTILITHOLOGIC SPECIMENS SIMULATING SEDIMENTARY FACIES CHANGES A Thesis by LAWRENCE DANA DYKE Approved as to style and content by: (Chai n Committee) (Head...

  14. CO2 - brine behavior using a Black - oil model + geomechanics

    E-Print Network [OSTI]

    Mathematical Model. The governing equations of coupled rock deformation and fluid flow are derived from mass conservation and momentum balance for both ...

  15. Computational Modeling of Self-organization of Dislocations and...

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

    Computational Modeling of Self-organization of Dislocations and Mesoscale Deformation of Metals Event Sponsor: Mathematics and Computing Science - LANS Seminar Start Date: Jun 19...

  16. N=4 Scattering Amplitudes and the Deformed Grassmannian

    E-Print Network [OSTI]

    Livia Ferro; Tomasz Lukowski; Matthias Staudacher

    2014-07-24T23:59:59.000Z

    Some time ago the general tree-level scattering amplitudes of N=4 Super Yang-Mills theory were expressed as certain Grassmannian contour integrals. These remarkable formulas allow to clearly expose the super-conformal, dual super-conformal, and Yangian symmetries of the amplitudes. Using ideas from integrability it was recently shown that the building blocks of the amplitudes permit a natural multi-parameter deformation. However, this approach had been criticized by the observation that it seemed impossible to reassemble the building blocks into Yangian-invariant deformed non-MHV amplitudes. In this note we demonstrate that the deformations may be succinctly summarized by a simple modification of the measure of the Grassmannian integrals, leading to a Yangian-invariant deformation of the general tree-level amplitudes. Interestingly, the deformed building-blocks appear as residues of poles in the spectral parameter planes. Given that the contour integrals also contain information on the amplitudes at loop-level, we expect the deformations to be useful there as well. In particular, applying meromorphicity arguments, they may be expected to regulate all notorious infrared divergences. We also point out relations to Gelfand hypergeometric functions and the quantum Knizhnik-Zamolodchikov equations.

  17. Size effects on the onset of plastic deformation during nanoindentation of thin films and patterned lines

    E-Print Network [OSTI]

    Van Vliet, Krystyn J.

    Size effects on the onset of plastic deformation during nanoindentation of thin films and patterned; accepted 13 August 2003 Plastic deformation of materials exhibits a strong size dependence when, particularly the transition from elastic to plastic deformation and the early stages of plastic deformation. We

  18. DEFORMING MEYER SETS JEONG-YUP LEE AND ROBERT V. MOODY

    E-Print Network [OSTI]

    Moody, Robert Vaughan

    DEFORMING MEYER SETS JEONG-YUP LEE AND ROBERT V. MOODY For our friend Ludwig Danzer, on the occasion of his 80th birthday. Abstract. A linear deformation of a Meyer set M in Rd is the image of M and sufficient condition for such a deformation to be a Meyer set. In the case that the deformation is a Meyer

  19. Petrology and micromechanics of experimentally deformed natural rock salt: Physical processes: Topical report

    SciTech Connect (OSTI)

    Hansen, F.D.

    1987-09-01T23:59:59.000Z

    Effects of impurities and microprocesses on the creep of natural salt samples are presented. Salts are analyzed from four sites (Palo Duro Unit 4 and Palo Duro Unit 5, Texas; Avery Island, Louisiana; and Salina Basin, Michigan). The salts have been deformed at temperatures and pressures that simulate repository conditions. Bulk chemistry, optical petrology, and microprobe analyses are used to identify the species and to quantify the amount of each impurity. General effects of impurities on the rheology of natural salt are discussed. The physical processes that control creep deformation of salt are identified by etchpit techniques. The nature of desolation motion which controls the creep behavior of salt changes dramatically over the temperature range of 25 to 200/degree/C. Physical bases for constitutive modeling are established through observations documented in this report. Composition of the salts range from nearly pure, uniform halite to a heterogeneous composite of halite and anhydrite. Impurities evidently increase creep resistance at lower test temperatures. At higher test temperatures, creep deformation is much less sensitive to the presence of impurities. Anhydrite is the only mineral species that correlates strongly with creep response. Generally, greater amounts of anhydrite increase the creep resistance. 13 refs., 11 figs., 12 tabs.

  20. A versatile facility for laboratory studies of viscoelastic and poroelastic behaviour of rocks

    SciTech Connect (OSTI)

    Jackson, Ian [Research School of Earth Sciences, Australian National University, Canberra ACT 0200 (Australia); Schijns, Heather; Schmitt, Douglas R. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1 (Canada); Mu Junjie; Delmenico, Alison [Department of Engineering, Australian National University, Canberra ACT 0200 (Australia)

    2011-06-15T23:59:59.000Z

    Novel laboratory equipment has been modified to allow both torsional and flexural oscillation measurements at sub-microstrain amplitudes, thereby providing seismic-frequency constraints on both the shear and compressional wave properties of cylindrical rock specimens within the linear regime. The new flexural mode capability has been tested on experimental assemblies containing fused silica control specimens. Close consistency between the experimental data and the results of numerical modelling with both finite-difference and finite-element methods demonstrates the viability of the new technique. The capability to perform such measurements under conditions of independently controlled confining and pore-fluid pressure, with emerging strategies for distinguishing between local (squirt) and global (specimen-wide) fluid flow, will have particular application to the study of frequency-dependent seismic properties expected of cracked and fluid-saturated rocks of the Earth's upper crust.

  1. The constitutive modeling of nitrile elastomers 

    E-Print Network [OSTI]

    Helaire, Lumas Terence

    1996-01-01T23:59:59.000Z

    the development of constitutive modes, dynamic mechanical tests were also used to determine if the material exhibited nonlinear viscoelastic behavior....

  2. JOURNAL OF MATERIALS SCIENCE 2012, IN PRESS DOI: 10.1007/S10853-012-6927-8 Viscoelastic properties of hollow glass particle filled vinyl ester matrix syntactic foams: effect of temperature and loading

    E-Print Network [OSTI]

    Gupta, Nikhil

    properties of hollow glass particle filled vinyl ester matrix syntactic foams: effect of temperature compositions of syntactic foams. Storage modulus, loss modulus, and glass transition temperature (Tg@poly.edu Abstract Viscoelastic properties of hollow particle reinforced composites called syntactic foams

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

    SciTech Connect (OSTI)

    Miller, Gregory H.; Forest, Gregory

    2011-12-22T23:59:59.000Z

    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.

  4. Microstructure, strengthening mechanisms and hot deformation behavior of an oxide-dispersion strengthened UFG Al6063 alloy

    SciTech Connect (OSTI)

    Asgharzadeh, H. [Department of Mechanical Engineering, University of Tabriz, P.O. Box 51666-16471, Tabriz (Iran, Islamic Republic of)] [Department of Mechanical Engineering, University of Tabriz, P.O. Box 51666-16471, Tabriz (Iran, Islamic Republic of); Kim, H.S. [Department of Materials Science and Engineering, Pohang University of Science and Technology, P.O. Box 790-784, Pohang (Korea, Republic of)] [Department of Materials Science and Engineering, Pohang University of Science and Technology, P.O. Box 790-784, Pohang (Korea, Republic of); Simchi, A., E-mail: simchi@sharif.edu [Department of Materials Science and Engineering and Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 11365-9466, Tehran (Iran, Islamic Republic of)

    2013-01-15T23:59:59.000Z

    An ultrafine-grained Al6063/Al{sub 2}O{sub 3} (0.8 vol.%, 25 nm) nanocomposite was prepared via powder metallurgy route through reactive mechanical alloying and hot powder extrusion. Scanning electron microcopy, transmission electron microscopy, and back scattered electron diffraction analysis showed that the grain structure of the nanocomposite is trimodal and composed of nano-size grains (< 0.1 {mu}m), ultrafine grains (0.1-1 {mu}m), and micron-size grains (> 1 {mu}m) with random orientations. Evaluation of the mechanical properties of the nanocomposite based on the strengthening-mechanism models revealed that the yield strength of the ultrafine-grained nanocomposite is mainly controlled by the high-angle grain boundaries rather than nanometric alumina particles. Hot deformation behavior of the material at different temperatures and strain rates was studied by compression test and compared to coarse-grained Al6063 alloy. The activation energy of the hot deformation process for the nanocomposite was determined to be 291 kJ mol{sup -1}, which is about 64% higher than that of the coarse-grained alloy. Detailed microstructural analysis revealed that dynamic recrystallization is responsible for the observed deformation softening in the ultrafine-grained nanocomposite. - Highlights: Black-Right-Pointing-Pointer The strengthening mechanisms of Al6063/Al{sub 2}O{sub 3} nanocomposite were evaluated. Black-Right-Pointing-Pointer Hot deformation behavior of the nanocomposite was studied. Black-Right-Pointing-Pointer The hot deformation activation energy was determined using consecutive models. Black-Right-Pointing-Pointer The restoration mechanisms and microstructural changes are presented.

  5. Temperature dependent deformation mechanisms in pure amorphous silicon

    SciTech Connect (OSTI)

    Kiran, M. S. R. N., E-mail: kiran.mangalampalli@anu.edu.au; Haberl, B.; Williams, J. S.; Bradby, J. E. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 0200 (Australia)

    2014-03-21T23:59:59.000Z

    High temperature nanoindentation has been performed on pure ion-implanted amorphous silicon (unrelaxed a-Si) and structurally relaxed a-Si to investigate the temperature dependence of mechanical deformation, including pressure-induced phase transformations. Along with the indentation load-depth curves, ex situ measurements such as Raman micro-spectroscopy and cross-sectional transmission electron microscopy analysis on the residual indents reveal the mode of deformation under the indenter. While unrelaxed a-Si deforms entirely via plastic flow up to 200?°C, a clear transition in the mode of deformation is observed in relaxed a-Si with increasing temperature. Up to 100?°C, pressure-induced phase transformation and the observation of either crystalline (r8/bc8) end phases or pressure-induced a-Si occurs in relaxed a-Si. However, with further increase of temperature, plastic flow rather than phase transformation is the dominant mode of deformation. It is believed that the elevated temperature and pressure together induce bond softening and “defect” formation in structurally relaxed a-Si, leading to the inhibition of phase transformation due to pressure-releasing plastic flow under the indenter.

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

    SciTech Connect (OSTI)

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

    2013-07-01T23:59:59.000Z

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

  7. Kinematic quantities of finite elastic and plastic deformation

    E-Print Network [OSTI]

    T. Fülöp; P. Ván

    2012-03-05T23:59:59.000Z

    Kinematic quantities for finite elastic and plastic deformations are defined via an approach that does not rely on auxiliary elements like reference frame and reference configuration, and that gives account of the inertial-noninertial aspects explicitly. These features are achieved by working on Galilean spacetime directly. The quantity expressing elastic deformations is introduced according to its expected role: to measure how different the current metric is from the relaxed/stressless metric. Further, the plastic kinematic quantity is the change rate of the stressless metric. The properties of both are analyzed, and their relationship to frequently used elastic and plastic kinematic quantities is discussed. One important result is that no objective elastic or plastic quantities can be defined from deformation gradient.

  8. Noncommutative deformations of quantum field theories, locality, and causality

    E-Print Network [OSTI]

    Michael A. Soloviev

    2010-12-16T23:59:59.000Z

    We investigate noncommutative deformations of quantum field theories for different star products, particularly emphasizing the locality properties and the regularity of the deformed fields. Using functional analysis methods, we describe the basic structural features of the vacuum expectation values of star-modified products of fields and field commutators. As an alternative to microcausality, we introduce a notion of $\\theta$-locality, where $\\theta$ is the noncommutativity parameter. We also analyze the conditions for the convergence and continuity of star products and define the function algebra that is most suitable for the Moyal and Wick-Voros products. This algebra corresponds to the concept of strict deformation quantization and is a useful tool for constructing quantum field theories on a noncommutative space-time.

  9. Animating Viscoelastic Fluids

    E-Print Network [OSTI]

    Goktekin, Tolga Gokce

    2011-01-01T23:59:59.000Z

    An introduction to the conjugate gradient method without theusing the conjugate gradient method best described in [

  10. Structural control of elastic moduli in ferrogels and the importance of non-affine deformations

    E-Print Network [OSTI]

    Giorgio Pessot; Peet Cremer; Dmitry Y. Borin; Stefan Odenbach; Hartmut Löwen; Andreas M. Menzel

    2014-10-21T23:59:59.000Z

    One of the central appealing properties of magnetic gels and elastomers is that their elastic moduli can reversibly be adjusted from outside by applying magnetic fields. The impact of the internal magnetic particle distribution on this effect has been outlined and analyzed theoretically. In most cases, however, affine sample deformations are studied and often regular particle arrangements are considered. Here we challenge these two major simplifications by a systematic approach using a minimal dipole-spring model. Starting from different regular lattices, we take into account increasingly randomized structures, until we finally investigate an irregular texture taken from a real experimental sample. On the one hand, we find that the elastic tunability qualitatively depends on the structural properties, here in two spatial dimensions. On the other hand, we demonstrate that the assumption of affine deformations leads to increasingly erroneous results the more realistic the particle distribution becomes. Understanding the consequences of the assumptions made in the modeling process is important on our way to support an improved design of these fascinating materials.

  11. Plastic Deformation in an Amorphous Ni-P Coating

    SciTech Connect (OSTI)

    Shen, Yongfeng; Liu, Wenning; Sun, Xin; Xue, W. Y.; Wang, Y. D.; Zuo, Liang; Liaw, Peter K.

    2012-05-01T23:59:59.000Z

    An experimental and numerical investigation of the hardness and associated plastic deformation in as-deposited and as-annealed nickel-phosphorus (Ni-P) coatings was conducted. In addition to the indentation-deformation behavior, the deformation morphology underneath the indenter was examined. The yield strength extracted from the indentation data is as high as 5.6 GPa, indicating pressure-sensitive plasticity. Results show that the as-deposited Ni-P coating was deformed appreciably through the shear-band mechanism with semi-circular and radial shear-band morphologies. From the incremental loading-unloading cyclic experiments, the phenomena on hardening and recovery, which have scarcely been recognized in amorphous materials at room temperature, were observed in the amorphous coating using instrumented nanoindentation. A numerical simulation of the interfacial indentation test between the Ni-P coating and the substrate reveals the pile-up and shear bands of the Ni-P coating that were observed during the indentation tests.

  12. Inhomogeneous deformation of a cone of Neo-Hookean material 

    E-Print Network [OSTI]

    Hariharakumar, Pradeep

    2001-01-01T23:59:59.000Z

    In this work we investigate, the nonlinear, elastic deformation of a cone made of a Neo-Hookean material. We use a semi-inverse method and assume a specific form of the displacement and the corresponding structure of the pressure field inside...

  13. Large Deformation Constitutive Laws for Isotropic Thermoelastic Materials

    SciTech Connect (OSTI)

    Plohr, Bradley J. [Los Alamos National Laboratory; Plohr, Jeeyeon N. [Los Alamos National Laboratory

    2012-07-25T23:59:59.000Z

    We examine the approximations made in using Hooke's law as a constitutive relation for an isotropic thermoelastic material subjected to large deformation by calculating the stress evolution equation from the free energy. For a general thermoelastic material, we employ the volume-preserving part of the deformation gradient to facilitate volumetric/shear strain decompositions of the free energy, its first derivatives (the Cauchy stress and entropy), and its second derivatives (the specific heat, Grueneisen tensor, and elasticity tensor). Specializing to isotropic materials, we calculate these constitutive quantities more explicitly. For deformations with limited shear strain, but possibly large changes in volume, we show that the differential equations for the stress components involve new terms in addition to the traditional Hooke's law terms. These new terms are of the same order in the shear strain as the objective derivative terms needed for frame indifference; unless the latter terms are negligible, the former cannot be neglected. We also demonstrate that accounting for the new terms requires that the deformation gradient be included as a field variable

  14. Deformation and $?$ clustering in excited states of $^{42}$Ca

    E-Print Network [OSTI]

    Yasutaka Taniguchi

    2014-04-09T23:59:59.000Z

    The coexistence of various low-lying deformed states in $^{42}$Ca and $\\alpha$--$^{38}$Ar correlations in those deformed states have been investigated using deformed-basis antisymmetrized molecular dynamics. Wave functions of the low-lying states are obtained via parity and angular momentum projections and the generator coordinate method (GCM). Basis wave functions of the GCM calculation are obtained via energy variations with constraints on the quadrupole deformation parameter $\\beta$ and the distance between $\\alpha$ and $^{38}$Ar clusters. The rotational band built on the $J^\\pi = 0_2^+$ (1.84 MeV) state as well as the $J^\\pi = 0_3^+$ (3.30 MeV) state are both reproduced. The coexistence of two additional $K^\\pi = 0^+$ rotational bands is predicted; one band is shown to be built on the $J^\\pi = 0_3^+$ state. Members of the ground-state band and the rotational band built on the $J^\\pi = 0_3^+$ state contain $\\alpha$--$^{38}$Ar cluster structure components.

  15. Experimental validation of finite element codes for welding deformations

    E-Print Network [OSTI]

    Boyer, Edmond

    Experimental validation of finite element codes for welding deformations H. M. Aarbogha,b, , M Institute for Energy Technology, N-2027 Kjeller, Norway. Abstract A single pass Metal Inert Gas welding which numerical codes quantifying welding stresses can be validated. It includes a mov- ing heat source

  16. CONTAINED PLASTIC DEFORMATION NEAR CRACKS AND NOTCHES UNDER LONGITUDINAL SHEAR

    E-Print Network [OSTI]

    CONTAINED PLASTIC DEFORMATION NEAR CRACKS AND NOTCHES UNDER LONGITUDINAL SHEAR James R. Rice* ABSTRACT An exact linear elastic-perfectly plastic solution is presented for the problem of a sharp notch coordinates corresponding to given stresses, position of the elastic-plastic boundary, and accompanying

  17. Geomorphic evidence for Late Cenozoic deformation, Wichita Moutains, Oklahoma

    E-Print Network [OSTI]

    Snell, Charles Burton

    1989-01-01T23:59:59.000Z

    be divided into two groups based on physiographic and geomorphic relationships. The upper group, containing the previously recognized Lake Altus granite platforms (western Wichita Mountains) and similar surfaces to the east, formed following Ogallala... of Pediments. Tentative Implications Correlation of Pediment Sets Implied Tectonic Activity HIGH PLAINS GEOLOGIC HISTORY. Physiography. Geology. Tertiary Period. Quaternary Period Late Cenozoic Deformation Salt Dissolution Subsidence. Tectonic...

  18. Efficient Retrieval of Deformed and Occluded Shapes Zusheng Rao1

    E-Print Network [OSTI]

    Petrakis, Euripides G.M.

    @cs.yorku.ca, petrakis@ced.tuc.gr, eem@cs.dal.ca Abstract We propose an approach for matching deformed and oc- cluded of Computer Science, Dalhousie University, eem@cs.dal.ca. This work was supported by a grant from the Natural

  19. Failing softly: A fracture theory of highly-deformable materials

    E-Print Network [OSTI]

    Tamar Goldman Boué; Roi Harpaz; Jay Fineberg; Eran Bouchbinder

    2015-03-24T23:59:59.000Z

    Highly-deformable materials, from synthetic hydrogels to biological tissues, are becoming increasingly important from both fundamental and practical perspectives. Their mechanical behaviors, in particular the dynamics of crack propagation during failure, are not yet fully understood. Here we propose a theoretical framework for the dynamic fracture of highly-deformable materials, in which the effects of a dynamic crack are treated with respect to the nonlinearly deformed (pre-stressed/strained), non-cracked, state of the material. Within this framework, we derive analytic and semi-analytic solutions for the near-tip deformation fields and energy release rates of dynamic cracks propagating in incompressible neo-Hookean solids under biaxial and uniaxial loading. We show that moderately large pre-stressing has a marked effect on the stress fields surrounding a crack's tip. We verify these predictions by performing extensive experiments on the fracture of soft brittle elastomers over a range of loading levels and propagation velocities, showing that the newly developed framework offers significantly better approximations to the measurements than standard approaches at moderately large levels of external loadings and high propagation velocities. This framework should be relevant to the failure analysis of soft and tough, yet brittle, materials.

  20. Qubit dynamics in a q-deformed oscillators environment

    E-Print Network [OSTI]

    S. L'Innocente; C. Lupo; S. Mancini

    2009-12-19T23:59:59.000Z

    We study the dynamics of one and two qubits plunged in a q-deformed oscillators environment. Specifically we evaluate the decay of quantum coherence and entanglement in time when passing from bosonic to fermionic environments. Slowing down of decoherence in the fermionic case is found. The effect only manifests at finite temperature.

  1. MECHANICAL PROPERTIES AND DEFORMATION MECHANISMS OF A COMMERCIALLY PURE TITANIUM

    E-Print Network [OSTI]

    Nemat-Nasser, Sia

    MECHANICAL PROPERTIES AND DEFORMATION MECHANISMS OF A COMMERCIALLY PURE TITANIUM S. NEMAT titanium (CP-Ti) is systematically investigated in quasi-static (Instron, servohydraulic) and dynamic (UCSD Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. Keywords: Titanium

  2. Automated Finite Element Analysis for Deformable Registration of Prostate Images

    E-Print Network [OSTI]

    1 Automated Finite Element Analysis for Deformable Registration of Prostate Images Jessica R, Marco Zaider Abstract-- Two major factors preventing the routine clinical use of finite element analysis the effort required to apply finite element analysis to image registration. Encouraging results are presented

  3. The Rate of Creep Deformation St Edmund's College, Cambridge

    E-Print Network [OSTI]

    Cambridge, University of

    and test the significant creep constitutive strain equations, 2.25Cr-1Mo steel has been selectedThe Rate of Creep Deformation By Yi Shen St Edmund's College, Cambridge University of Cambridge my parents Liping Wei and Derong Shen. #12;v Abstract Creep and creep fracture represent one

  4. Mechanical deformations of boron nitride nanotubes in crossed junctions

    SciTech Connect (OSTI)

    Zhao, Yadong; Chen, Xiaoming; Ke, Changhong, E-mail: cke@binghamton.edu [Department of Mechanical Engineering, State University of New York at Binghamton, Binghamton, New York 13902 (United States); Park, Cheol [NASA Langley Research Center, Hampton, Virginia 23681 (United States); Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Fay, Catharine C. [NASA Langley Research Center, Hampton, Virginia 23681 (United States); Stupkiewicz, Stanislaw [Institute of Fundamental Technological Research, Warsaw (Poland)

    2014-04-28T23:59:59.000Z

    We present a study of the mechanical deformations of boron nitride nanotubes (BNNTs) in crossed junctions. The structure and deformation of the crossed tubes in the junction are characterized by using atomic force microscopy. Our results show that the total tube heights are reduced by 20%–33% at the crossed junctions formed by double-walled BNNTs with outer diameters in the range of 2.21–4.67?nm. The measured tube height reduction is found to be in a nearly linear relationship with the summation of the outer diameters of the two tubes forming the junction. The contact force between the two tubes in the junction is estimated based on contact mechanics theories and found to be within the range of 4.2–7.6 nN. The Young's modulus of BNNTs and their binding strengths with the substrate are quantified, based on the deformation profile of the upper tube in the junction, and are found to be 1.07?±?0.11 TPa and 0.18–0.29 nJ/m, respectively. Finally, we perform finite element simulations on the mechanical deformations of the crossed BNNT junctions. The numerical simulation results are consistent with both the experimental measurements and the analytical analysis. The results reported in this paper contribute to a better understanding of the structural and mechanical properties of BNNTs and to the pursuit of their applications.

  5. Deforming the Gauss-Manin Connection Glenn Stevens

    E-Print Network [OSTI]

    Stevens, Glenn

    Deforming the Gauss-Manin Connection Glenn Stevens (Research partially supported by NSF grant: DMS 0071065) §0. The Gauss-Manin Connection. Let p > 2 be a prime and N 4. The p-adic modular curve X1(Np(v) be the largest connected wide open neighborhood of Z on which the canonical subgroup is defined. Let : E - X

  6. The nonlinear mechanics of slender structures undergoing large deformations

    E-Print Network [OSTI]

    van der Heijden, Gert

    if one is interested in phenomena on length scales much larger than the lateral dimensions rod theory is applied include the looping of ocean cables [7] and the buckling of oilwell dring) boreholes, and therefore present the problem of structural deformation and buckling in the presence

  7. Rigid-Plastic Approximations for Predicting Plastic Deformation of Cylindrical Shells Subject to Dynamic Loading

    E-Print Network [OSTI]

    Hoo Fatt, Michelle S.

    A theoretical approach was developed for predicting the plastic deformation of a cylindrical shell subject to asymmetric dynamic loads. The plastic deformation of the leading generator of the shell is found by solving for ...

  8. MONITORING OF SALT-INDUCED DEFORMATIONS IN POROUS SYSTEMS BY MICROSCOPIC SPECKLE PATTERN INTERFEROMETRY

    E-Print Network [OSTI]

    Hinsch, Klaus

    MONITORING OF SALT-INDUCED DEFORMATIONS IN POROUS SYSTEMS BY MICROSCOPIC SPECKLE PATTERN porosity distribution, and its negligible humidity expansion. The glass sam- ples, soaked with salt: electronic speckle pattern interferometry, deformation measurement, salt crys- tallization, phase transition

  9. Deformation mechanics of quartz at a single asperity under hydrothermal conditions

    E-Print Network [OSTI]

    Bakku, Sudhish Kumar

    2010-01-01T23:59:59.000Z

    Pressure solution is a naturally occurring deformation process in fluid-bearing rocks, with implications for sediment consolidation rates and deformation in the mid to upper crust. The process involves dissolution at ...

  10. Normal and lateral Casimir forces between deformed plates

    SciTech Connect (OSTI)

    Emig, Thorsten; Hanke, Andreas; Golestanian, Ramin; Kardar, Mehran [Institut fuer Theoretische Physik, Universitaet zu Koeln, Zuelpicher Strasse 77, D-50937 Cologne (Germany); Institut fuer Theoretische Physik, Universitaet Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart (Germany); Institute for Advanced Studies in Basic Sciences, Zanjan 45195-159 (Iran, Islamic Republic of); Institute for Studies in Theoretical Physics and Mathematics, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Physics Department, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2003-02-01T23:59:59.000Z

    The Casimir force between macroscopic bodies depends strongly on their shape and orientation. To study this geometry dependence in the case of two deformed metal plates, we use a path-integral quantization of the electromagnetic field which properly treats the many-body nature of the interaction, going beyond the commonly used pairwise summation (PWS) of van der Waals forces. For arbitrary deformations we provide an analytical result for the deformation induced change in the Casimir energy, which is exact to second order in the deformation amplitude. For the specific case of sinusoidally corrugated plates, we calculate both the normal and the lateral Casimir forces. The deformation induced change in the Casimir interaction of a flat and a corrugated plate shows an interesting crossover as a function of the ratio of the mean plate distance H to the corrugation length {lambda}: For {lambda}<>H. The amplitude of the lateral force between two corrugated plates which are out of registry is shown to have a maximum at an optimal wavelength of {lambda}{approx_equal}2.5 H. With increasing H/{lambda} > or approx. 0.3 the PWS approach becomes a progressively worse description of the lateral force due to many-body effects. These results may be of relevance for the design and operation of novel microelectromechanical systems (MEMS) and other nanoscale devices.

  11. Active Perception of Deformable Objects using 3D Cameras Guillem Aleny`a, Francesc Moreno-Noguer, Arnau Ramisa, and Carme Torras

    E-Print Network [OSTI]

    Moreno-Noguer, Francesc

    : grasping of textiles and plant leaf modelling. I. INTRODUCTION 3D perception of deformable objects using RGB cameras has been one the most studied research fields within com- puter vision. There exist and Innovation under project DPI2008-06022 and MIPRCV Consolider Ingenio CSD2007-00018, and the Catalan Research

  12. Early detection of brine and CO2 leakage through abandoned wells using pressure and surface-deformation monitoring data: Concept and

    E-Print Network [OSTI]

    Zhou, Quanlin

    and surface-deformation modeling tools to estimate the location and permeability of leaky features by Elsevier Ltd. 1. Introduction The ability to detect CO2 leakage is a key component of risk assessment storage for- mation to shallower groundwater aquifers, ultimately to the atmosphere, through abandoned

  13. Conformal invariance of the planar beta-deformed N=4 SYM theory requires beta real

    E-Print Network [OSTI]

    Federico Elmetti; Andrea Mauri; Silvia Penati; Alberto Santambrogio; Daniela Zanon

    2006-06-14T23:59:59.000Z

    We study the \\cal{N}=1 SU(N) SYM theory which is a marginal deformation of the \\cal{N}=4 theory, with a complex deformation parameter \\beta. We consider the large N limit and study perturbatively the conformal invariance condition. We find that finiteness requires reality of the deformation parameter \\beta.

  14. PLASTIC VERSUS ELASTIC DEFORMATION EFFECTS ON MAGNETIC BARKHAUSEN NOISE IN STEEL

    E-Print Network [OSTI]

    Clapham, Lynann

    PLASTIC VERSUS ELASTIC DEFORMATION EFFECTS ON MAGNETIC BARKHAUSEN NOISE IN STEEL C.-G. STEFANITA, D) AbstractÐA study was performed to dierentiate the eects of elastic and plastic deformation on magnetic samples subjected to varying degrees of uniaxial elastic and plastic deformation up to H40% strain

  15. ACM Reference Format Weber, O., Gotsman, C. 2010. Controllable Conformal Maps for Shape Deformation and Interpolation.

    E-Print Network [OSTI]

    Kazhdan, Michael

    ACM Reference Format Weber, O., Gotsman, C. 2010. Controllable Conformal Maps for Shape Deformation.1145/1778765.1778815 Controllable Conformal Maps for Shape Deformation and Interpolation Ofir Weber Craig Gotsman Technion ­ Israel Institute of Technology weber@cs.technion.ac.il gotsman@cs.technion.ac.il Figure 1: Conformal deformation

  16. Spatial scaling of Arctic sea ice deformation H. L. Stern1

    E-Print Network [OSTI]

    Lindsay, Ron

    to a power law with exponent $À0.2, over a scale range from 10 to 1000 km (e.g., deformation rate doubles ice based on granular or fracture mechanics. The scaling exponent in the power law relationship tends in the deformation rate has already been documented (from buoy data). However, the net effect of several deformation

  17. Features Extraction from Point Clouds for Automated Detection of Deformations on Automotive Body Parts

    E-Print Network [OSTI]

    Payeur, Pierre

    Features Extraction from Point Clouds for Automated Detection of Deformations on Automotive Body with the problem of detecting unwanted deformations on automotive body part in mind, where feature line detection, surface map analysis, deformation detection, pattern recognition, quality control, automotive body parts

  18. Oil and Gas CDT Bots in Rocks: Intelligent Rock Deformation for Fault Rock

    E-Print Network [OSTI]

    Henderson, Gideon

    Heriot-Watt University, Institute of Petroleum Engineering Supervisory Team · Dr Helen Lewis, Heriot://www.pet.hw.ac.uk/staff-directory/jimsomerville.htm Key Words Nano/Micro sensors; faults; fault zones; geomechanics; rock mechanics; rock deformation-deformed equivalent, a different lab-deformed example and a geomechanical simulation of a fault zone showing permanent

  19. Tunable Dipolar Capillary Deformations for Magnetic Janus Particles at Fluid-Fluid Interfaces

    E-Print Network [OSTI]

    Qingguang Xie; Gary B. Davies; Florian Günther; Jens Harting

    2015-03-12T23:59:59.000Z

    Janus particles have attracted significant interest as building blocks for complex materials in recent years. Furthermore, capillary interactions have been identified as a promising tool for directed self-assembly of particles at fluid-fluid interfaces. In this paper, we develop theoretical models describing the behaviour of magnetic Janus particles adsorbed at fluid-fluid interfaces interacting with an external magnetic field. Using numerical simulations, we test the models predictions and show that the magnetic Janus particles deform the interface in a dipolar manner. We suggest how to utilise the resulting dipolar capillary interactions to assemble particles at a fluid-fluid interface, and further demonstrate that the strength of these interactions can be tuned by altering the external field strength, opening up the possibility to create novel, reconfigurable materials.

  20. Tunable Dipolar Capillary Deformations for Magnetic Janus Particles at Fluid-Fluid Interfaces

    E-Print Network [OSTI]

    Xie, Qingguang; Günther, Florian; Harting, Jens

    2015-01-01T23:59:59.000Z

    Janus particles have attracted significant interest as building blocks for complex materials in recent years. Furthermore, capillary interactions have been identified as a promising tool for directed self-assembly of particles at fluid-fluid interfaces. In this paper, we develop theoretical models describing the behaviour of magnetic Janus particles adsorbed at fluid-fluid interfaces interacting with an external magnetic field. Using numerical simulations, we test the models predictions and show that the magnetic Janus particles deform the interface in a dipolar manner. We suggest how to utilise the resulting dipolar capillary interactions to assemble particles at a fluid-fluid interface, and further demonstrate that the strength of these interactions can be tuned by altering the external field strength, opening up the possibility to create novel, reconfigurable materials.

  1. Reaction cross-section calculations using new experimental and theoretical level structure data for deformed nuclei

    SciTech Connect (OSTI)

    Hoff, R.W.; Gardner, D.G.; Gardner, M.A.

    1984-10-05T23:59:59.000Z

    A technique for modeling quasiparticle excitation energies and rotational parameters in odd-odd deformed nuclei has been used to construct sets of discrete states with energy 0 to 1.5 MeV in /sup 176/Lu and /sup 236/Np. These data were used as part of the input for calculation of isomer production cross-section ratios in the /sup 175/Lu(n,..gamma..)/sup 176/Lu and /sup 237/Np(n,2n)/sup 236/Np reactions. In order to achieve agreement with experiment, it has been found necessary to include in the modeled set many rotational bands (35 to 95), which are comprised of hundreds of levels with their gamma-ray branching ratios. It is essential that enough bands be included to produce a representative selection of K quantum numbers in the de-excitation cascade. 20 refs., 3 figs., 3 tabs.

  2. Using Neutron Star Observations to Determine Crust Thicknesses, Moments of Inertia, and Tidal Deformabilities

    E-Print Network [OSTI]

    Andrew W. Steiner; Stefano Gandolfi; Farrukh J. Fattoyev; William G. Newton

    2015-01-25T23:59:59.000Z

    We perform a systematic assessment of models for the equation of state (EOS) of dense matter in the context of recent neutron star mass and radius measurements to obtain a broad picture of the structure of neutron stars. We demonstrate that currently available neutron star mass and radius measurements provide strong constraints on moments of inertia, tidal deformabilities, and crust thicknesses. A measurement of the moment of inertia of PSR J0737-3039A with 10% error, without any other information from observations, will constrain the EOS over a range of densities to within 50%$-$60%. We find tidal deformabilities between 0.6 and $6\\times 10^{36}$ g cm$^{2}$ s$^{2}$ (to 95% confidence) for $M=1.4~\\mathrm{M}_{\\odot}$, and any measurement which constrains this range will provide an important constraint on dense matter. The crustal fraction of the moment of inertia can be as large as 10% for $M=1.4~\\mathrm{M}_{\\odot}$ permitting crusts to have a large enough moment of inertia reservoir to explain glitches in the Vela pulsar even with a large amount of superfluid entrainment. Finally, due to the uncertainty in the equation of state, there is at least a 40% variation in the thickness of the crust for a fixed mass and radius, which implies that future simulations of the cooling of a neutron star crust which has been heated by accretion will need to take this variation into account.

  3. DEFORMATION LOCALIZATION AND DISLOCATION CHANNEL DYNAMICS IN NEUTRON IRRADIATED AUSTENITIC STAINLESS STEELS

    SciTech Connect (OSTI)

    Gussev, Maxim N [ORNL; Field, Kevin G [ORNL; Busby, Jeremy T [ORNL

    2015-01-01T23:59:59.000Z

    The dynamics of deformation localization and dislocation channel formation were investigated in situ in a neutron irradiated AISI 304 austenitic stainless steel and a model 304-based austenitic alloy by combining several analytical techniques including optic microscopy and laser confocal microscopy, scanning electron microscopy, electron backscatter diffraction and transmission electron microscopy. Channel formation was observed at 70% of the formal tensile yield stress for both alloys. It was shown that triple junction points do not always serve as a source of dislocation channels; at stress levels below the yield stress, channels often formed near the middle of the grain boundary. For a single grain, the role of elastic stiffness value (Young modulus) in the channel formation was analyzed; it was shown that in the irradiated 304 steels the initial channels appeared in soft grains with a high Schmid factor located near stiff grains with high elastic stiffness. The spatial organization of channels in a single grain was analyzed; it was shown that secondary channels operating in the same slip plane as primary channels often appeared at the middle or at one third of the way between primary channels. The twinning nature of dislocation channels was analyzed for grains of different orientation using TEM. It was shown that in the AISI 304 steel, channels were twin-free in grains oriented close to [001] and [101] of standard unit triangle; [111]-grains and grains oriented close to Schmid factor maximum contained deformation twins.

  4. Photon polarization tensor on deformed spacetime: A four-photon-tadpole contribution

    E-Print Network [OSTI]

    Horvat, Raul; You, Jiangyang

    2015-01-01T23:59:59.000Z

    We present our results for the four-photon-tadpole diagram in a noncommutative U(1) gauge field theory deformed by the Seiberg-Witten (SW) maps and evaluated via a full-fledged theta-exact approach. Such a contribution, vanishing in the four-dimensional commutative theory under dimensional regularization, now reveals a quadratic IR divergence arising from the UV/IR connection in the Feynman loop integrals. We show that the four-photon-tadpole diagram in our model has the same tensorial structure as the three-photon-bubble diagram studied previously by us. Employing two distinct theta-exact gauge field strength SW maps and including various gauge-invariance inspired deformation parameters, we perform a sum over both the relevant diagrams to obtain the full result for the one-loop photon self-energy. We observe that contrary to the bubble diagram alone, where a selection of parameters that makes it free of UV/IR mixing anomalies does exists, one cannot do away with quadratic IR divergences in the sum, thus miss...

  5. A new approach to deformation equations of noncommutative KP hierarchies

    E-Print Network [OSTI]

    Aristophanes Dimakis; Folkert Muller-Hoissen

    2007-03-21T23:59:59.000Z

    Partly inspired by Sato's theory of the Kadomtsev-Petviashvili (KP) hierarchy, we start with a quite general hierarchy of linear ordinary differential equations in a space of matrices and derive from it a matrix Riccati hierarchy. The latter is then shown to exhibit an underlying 'weakly nonassociative' (WNA) algebra structure, from which we can conclude, refering to previous work, that any solution of the Riccati system also solves the potential KP hierarchy (in the corresponding matrix algebra). We then turn to the case where the components of the matrices are multiplied using a (generalized) star product. Associated with the deformation parameters, there are additional symmetries (flow equations) which enlarge the respective KP hierarchy. They have a compact formulation in terms of the WNA structure. We also present a formulation of the KP hierarchy equations themselves as deformation flow equations.

  6. Kinetic Bounding Volume Hierarchies for Collision Detection of Deformable Objects

    E-Print Network [OSTI]

    Gabriel Zachmann; Rene Weller

    2006-01-01T23:59:59.000Z

    We present novel algorithms for updating bounding volume hierarchies of objects undergoing arbitrary deformations. Therefore, we introduce two new data structures, the kinetic AABB tree and the kinetic BoxTree. The event-based approach of the kinetic data structures framework enables us to show that our algorithms are optimal in the number of updates. Moreover, we show a lower bound for the total number of BV updates, which is independent of the number of frames. Furthermore, we present a kinetic data structures which uses the kinetic AABB tree for collision detection and show that this structure can be easily extended for continuous collision detection of deformable objects. We performed a comparison of our kinetic approaches with the classical bottom-up update method. The results show that our algorithms perform up to ten times faster in practically relevant scenarios.

  7. q-quaternions and q-deformed su(2) instantons

    SciTech Connect (OSTI)

    Fiore, Gaetano [Dipartimento di Matematica e Applicazioni, Universita 'Federico II', V. Claudio 21, 80125 Naples (Italy) and INFN Sezione di Napoli, Complesso MSA, V. Cintia, 80126 Naples (Italy)

    2007-10-15T23:59:59.000Z

    We construct (anti-)instanton solutions of a would-be q-deformed su(2) Yang-Mills theory on the quantum Euclidean space R{sub q}{sup 4} [the SO{sub q}(4)-covariant noncommutative space] by reinterpreting the function algebra on the latter as a q-quaternion bialgebra. Since the (anti-)self-duality equations are covariant under the quantum group of deformed rotations, translations, and scale change, by applying the latter we can generate new solutions from the one centered at the origin and with unit size. We also construct multi-instanton solutions. As they depend on noncommuting parameters playing the roles of 'sizes' and 'coordinates of the centers' of the instantons, this indicates that the moduli space of a complete theory should be a noncommutative manifold. Similarly, gauge transformations should be allowed to depend on additional noncommutative parameters.

  8. Shape of Lambda hypernuclei in (beta,gamma) deformation plane

    E-Print Network [OSTI]

    Myaing Thi Win; K. Hagino; T. Koike

    2010-12-15T23:59:59.000Z

    We study the shape of $\\Lambda$ hypernuclei in the full ($\\beta,\\gamma$) deformation plane, including both axially symmetric and triaxial quadrupole deformations. To this end, we use the constrained Skyrme Hartree-Fock+BCS method on the three-dimensional Cartesian mesh. The potential energy surface is analyzed for carbon hypernuclei as well as for sd-shell hypernuclei such as $^{27,29}_{\\Lambda}$Si and $^{25,27}_{\\Lambda}$Mg. We show that the potential energy surface in the ($\\beta,\\gamma$) plane is similar to each other between the hypernuclei and the corresponding core nuclei, although the addition of $\\Lambda$ hyperon makes the energy surface somewhat softer along the $\\gamma$ direction. Our calculation implies that the energy of the $\\gamma$ vibration for $^{25,27}_{\\Lambda}$Mg nuclei is lowered by about 0.15 MeV with respect to that of $^{24,26}$Mg nuclei.

  9. Halos in a deformed relativistic Hartree-Bogoliubov theory in continuum

    SciTech Connect (OSTI)

    Li Lulu; Meng Jie; Ring, P.; Zhao Enguang; Zhou Shangui [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China) and Department of Physics, University of Stellenbosch, Stellenbosch (South Africa); Physikdepartment, Technische Universitaet Muenchen, 85748 Garching (Germany) and State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China) and Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China)

    2012-10-20T23:59:59.000Z

    In this contribution we present some recent results about neutron halos in deformed nuclei. A deformed relativistic Hartree-Bogoliubov theory in continuumhas been developed and the halo phenomenon in deformed weakly bound nuclei is investigated. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation of the core and the particles in the halo. Magnesium and neon isotopes are studied and detailed results are presented for the deformed neutron-rich and weakly bound nuclei {sup 42}Mg. The core of this nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the existence of halos in deformed nuclei and for the occurrence of this decoupling effect are discussed.

  10. Transient deformation properties of Zircaloy for LOCA simulation. Final report

    SciTech Connect (OSTI)

    Hann, C. R.; Mohr, C. L.; Busness, K. M.; Olson, N. J.; Reich, F. R.; Stewart, K. B.

    1980-05-01T23:59:59.000Z

    This experimental data report is Volume 4 of a series of 5 volumes describing the oxidation and deformation rate behavior of Zircaloy cladding under simulated LOCA conditions. It contains listings of strain versus stress, time, and temperature evaluated from the numerical constitutive relationships and the original data used to develop them. This volume also contains listings of the ramp load, pressure, and temperature test data from both current and previous phases of the series, as well as material describing applications of the data.

  11. SU(3) symmetry in the triaxially deformed harmonic oscillator

    SciTech Connect (OSTI)

    Sugawara-Tanabe, Kazuko [Otsuma Women's University, Tama, Tokyo 206-8540 (Japan); Tanabe, Kosai [Department of Physics, Saitama University, Sakura-Ku, Saitama 338-8570 (Japan); Theoretical Nuclear Physics Laboratory, RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Arima, Akito [Science Museum, Japan Science Foundation, Tokyo 102-0091 (Japan); Gruber, Bruno [College of Science, Southern Illinois University, Carbondale, Illinois 62901 (United States)

    2009-10-15T23:59:59.000Z

    An anisotropic harmonic oscillator Hamiltonian can be brought into invariant form under SU(3) transformations by applying nonlinear transformations to the oscillator bosons. The classification of the single-particle levels based on this covering group predicts magic numbers for the triaxial oscillator. It is shown that when the deformation |{delta}| is not too large, the physical operators are approximated by the group operators. Estimation is carried out for the alignment of orbital angular momentum in a triaxial field.

  12. Method for making biaxially textured articles by plastic deformation

    DOE Patents [OSTI]

    Goyal, Amit (Knoxville, TN)

    2002-01-01T23:59:59.000Z

    A method of preparing a biaxially textured article comprises the steps of providing a metal preform, coating or laminating the preform with a metal layer, deforming the layer to a sufficient degree, and rapidly recrystallizing the layer to produce a biaxial texture. A superconducting epitaxial layer may then be deposited on the biaxial texture. In some embodiments the article further comprises buffer layers, electromagnetic devices or electro-optical devices.

  13. Survey of odd-odd deformed nuclear spectroscopy

    SciTech Connect (OSTI)

    Hoff, R.W.

    1993-09-14T23:59:59.000Z

    In this paper, we survey the current experimental data that support assignment of rotational bands in odd-odd deformed nuclear in the rare earth and actinide regions. We present the results of a new study of {sup 170}Mt nuclear structure. In a comparing experimental and calculated Gallagher-Moszkowski matrix elements for rare earth-region nuclei, we have developed a new approach to the systematics of these matrix elements.

  14. Deformation of shale: mechanical properties and indicators of mechanisms

    E-Print Network [OSTI]

    Ibanez, William Dayan

    1993-01-01T23:59:59.000Z

    Basins, shales of Devonian age are commonly considered reservoir rocks I' or natural gas [Woodward, 1958; Lockett, 1968; Long, 1979; Gonzales and Johnson, 1985], Economic gas production from the Devonian shales of these basins is associated...] and slates [Donath, 1961], may be expected to be weak. Finally, Microstructural studies of deformed shales have been restricted by optical resolution, and the role of crystal plasticity in clays may have been overlooked. Results for the brittle and semi...

  15. 2008 Rock Deformation GRC - Conference August 3-8, 2008

    SciTech Connect (OSTI)

    James G. Hirth

    2009-09-21T23:59:59.000Z

    The GRC on Rock Deformation highlights the latest research in brittle and ductile rock mechanics from experimental, field and theoretical perspectives. The conference promotes a multi-disciplinary forum for assessing our understanding of rock strength and related physical properties in the Earth. The theme for the 2008 conference is 'Real-time Rheology'. Using ever-improving geophysical techniques, our ability to constrain the rheological behavior during earthquakes and post-seismic creep has improved significantly. Such data are used to investigate the frictional behavior of faults, processes responsible for strain localization, the viscosity of the lower crust, and viscous coupling between the crust and mantle. Seismological data also provide information on the rheology of the lower crust and mantle through analysis of seismic attenuation and anisotropy. Geologists are improving our understanding of rheology by combining novel analyses of microstructures in naturally deformed rocks with petrologic data. This conference will bring together experts and students in these research areas with experimentalists and theoreticians studying the same processes. We will discuss and assess where agreement exists on rheological constraints derived at different length/time scales using different techniques - and where new insight is required. To encompass the elements of these topics, speakers and discussion leaders with backgrounds in geodesy, experimental rock deformation, structural geology, earthquake seismology, geodynamics, glaciology, materials science, and mineral physics will be invited to the conference. Thematic sessions will be organized on the dynamics of earthquake rupture, the rheology of the lower crust and coupling with the upper mantle, the measurement and interpretation of seismic attenuation and anisotropy, the dynamics of ice sheets and the coupling of reactive porous flow and brittle deformation for understanding geothermal and chemical properties of the shallow crust that are important for developing ideas in CO2 sequestration, geothermal and petrochemical research and the mechanics of shallow faults.

  16. Adhesive joint and composites modeling in SIERRA.

    SciTech Connect (OSTI)

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

    2005-11-01T23:59:59.000Z

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

  17. Master Thesis Phase-field Modeling of

    E-Print Network [OSTI]

    Cambridge, University of

    Department of Ferrous Technology (Computational Metallurgy) Graduate Institute of Ferrous Technology Pohang of Ferrous Technology (Computational Metallurgy) Graduate Institute of Ferrous Technology Pohang University-field Modeling of Crystal Growth during Deformation Department of Ferrous Technology (Computational Metallurgy

  18. Characterization Of High-Stroke High-Aspect Ratio Micro Electro Mechanical Systems Deformable Mirrors For Adaptive Optics

    E-Print Network [OSTI]

    Bouchti, Mohamed Amine

    2013-01-01T23:59:59.000Z

    Journal of Microelectromechanical Systems 8, 497– 8)High-aspect ratio microelectromechanical systems deformable

  19. An elastic, plastic, viscous model for slow shear of a liquid foam

    E-Print Network [OSTI]

    Philippe Marmottant; François Graner

    2007-07-06T23:59:59.000Z

    We suggest a scalar model for deformation and flow of an amorphous material such as a foam or an emulsion. To describe elastic, plastic and viscous behaviours, we use three scalar variables: elastic deformation, plastic deformation rate and total deformation rate; and three material specific parameters: shear modulus, yield deformation and viscosity. We obtain equations valid for different types of deformations and flows slower than the relaxation rate towards mechanical equilibrium. In particular, they are valid both in transient or steady flow regimes, even at large elastic deformation. We discuss why viscosity can be relevant even in this slow shear (often called "quasi-static") limit. Predictions of the storage and loss moduli agree with the experimental literature, and explain with simple arguments the non-linear large amplitude trends.

  20. Effects of heterogeneity and friction on the deformation and strength of rock

    SciTech Connect (OSTI)

    Nihei, K.T.; Myer, L.R.; Liu, Z.; Cook, N.G.W. [Lawrence Berkeley Lab., CA (United States); Kemeny, J.M. [Univ., of Arizona, Tucson, AZ (United States). Dept. of Mineralogy and Geological Engineering

    1994-03-01T23:59:59.000Z

    Experimental observations of the evolution of damage in rocks during compressive loading indicate that macroscopic failure occurs predominantly by extensile crack growth parallel or subparallel to the maximum principal stress. Extensile microcracks initiate at grain boundaries and open pores by a variety of micromechanical processes which may include grain bending, Brazilian type fracture and grain boundary sliding. Microstructural heterogeneity in grain size, strength and shape determines the magnitude of the local tensile stresses which produce extensile microcracking and the stability with which these microcracks coalesce to form macrocracks. Friction at grain boundaries and between the surfaces of microcracks reduces the strain energy available for extensile crack growth and increases the stability of microcrack growth. In clastic rocks, frictional forces may improve the conditions for extensile microcrack growth by constraining the amount of sliding and rotation of individual grains. Micromechanical models are used to investigate the effects of heterogeneity and friction on the deformation and strength of crystalline and clastic rocks.