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1

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

Open Energy Info (EERE)

Four-Dimensional Viscoelastic Deformation Model For Long Valley Caldera, California, Between 1995 And 2000 Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal...

2

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

Open Energy Info (EERE)

Four-Dimensional Viscoelastic Deformation Model For Long Valley Caldera, Four-Dimensional Viscoelastic Deformation Model For Long Valley Caldera, California, Between 1995 And 2000 Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Four-Dimensional Viscoelastic Deformation Model For Long Valley Caldera, California, Between 1995 And 2000 Details Activities (3) Areas (1) Regions (0) Abstract: We investigate the effects of viscoelastic (VE) rheologies surrounding a vertically dipping prolate spheroid source during an active period of time-dependent deformation between 1995 and 2000 at Long Valley caldera. We model a rapid magmatic inflation episode 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.,

3

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

E-Print Network (OSTI)

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 to obtain the effective thermal and mechanical properties and time-dependent response of the composites. The particle and matrix constituents are made of isotropic homogeneous viscoelastic bodies undergoing small deformation gradients. Perfect bonds are assumed along the sub-cell???s interfaces. The coupling between the thermal and mechanical response is attributed to the dissipation of energy due to the viscoelastic deformation and temperature dependent material parameters in the viscoelastic constitutive model. The micromechanical relations are formulated in terms of incremental average field quantities, i.e., stress, strain, heat flux and temperature gradient, in the sub-cells. The effective mechanical properties and coefficient of thermal expansion are derived by satisfying displacement- and traction continuities at the interfaces during the thermo-viscoelastic deformations. The effective thermal conductivity is formulated by imposing heat flux- and temperature continuities at the subcells??? interfaces. The expression of the effective specific heat at a constant stress is also established. A time integration algorithm for simultaneously solving the equations that govern heat conduction and thermoviscoelastic deformations of isotropic materials is developed. The algorithm is then incorporated within each sub-cell of the micromechanical model together with the macroscopic energy equation to determine the effective coupled thermoviscoelastic response of the particulate composite. The numerical formulation is implemented within the ABAQUS, general purpose displacement based FE software, allowing for analyzing coupled heat conduction and deformations of composite structures. Experimental data on the effective thermal properties and time dependent responses of particulate composites available in the literature are used to verify the micromechanical model formulation. The multiscale model capability is also examined by comparing the field variables, i.e., temperature, displacement, stresses and strains, obtained from heterogeneous and homogeneous composite structures, during the transient heat conduction and deformations. Examples of coupled thermoviscoelastic analyses of particulate composites and functionally graded structures are also presented. The present micromechanical modeling approach is found to be computationally efficient and shows good agreement with experiments in predicting the effective thermo-mechanical response of particulate composites and functionally graded materials. Our analyses forecast a better design for creep resistant and less dissipative structures using particulate composites and functionally graded materials.

Khan, Kamran Ahmed

2011-05-01T23:59:59.000Z

4

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

E-Print Network (OSTI)

This thesis analyzes the implementation of surface bonded piezoelectric actuators to control or minimize the deformation in elastic or viscoelastic cantilever beams due to simultaneous heat and moisture diffusion. The problem is addressed in the context of linearized elasticity and linearized viscoelasticity. The constitutive equations are derived from the balance laws for mass, linear and angular momenta, energy, entropy and the second law of thermodynamics. The constitutive equations for linearized elasticity are then obtained as a consequence of small deformation assumption. The temperature and moisture induced deformation is introduced through the coefficient of thermal expansion CTE and coefficient of moisture expansion CME. The constitutive equations for linearized viscoelasticity are obtained by correspondence principle. The coupled temperature and moisture diffusion equations are obtained as a consequence of Clausius-Duhem inequality. The extent of coupling between heat conduction and moisture diffusion phenomena is studied by varying the ratio of their diffusivities and a non-dimensional coupling parameter. The effect of coupled unsteady heat conduction and moisture diffusion phenomena on the short and long term response characteristics of the beam such as displacement, stress and strain fields is studied. Based on these response characteristics, the magnitude of external actuating voltage required to minimize deformation is predicted. This is followed by a comparative study of the field 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 is assumed to be thermorheologically simple. The shift factor is assumed to be a linear function of temperature and moisture fields. To address this problem numerically, a finite difference formulation is presented for the field equations and boundary conditions. This numerical scheme is validated by solving the problem of uniformly loaded cantilever beam and comparing the results with the analytical solution known a priori. The results obtained numerically are validated by comparison with experimental results. It is observed that the under the effect of external actuation, the stress and displacement fields are largely minimized in all four cases chosen for study. The bending in the unactuated viscoelastic beam is more pronounced than bending in the unactuated elastic beam. This is due to the softening of the material with time due to evolving temperature and moisture fields. However, relatively lesser external actuating voltage is necessary to minimize bending in the former case compared to the latter. The magnitude of actuating electric field required in the piezoelectric layer suggests a need to address the problem with in a non-linear framework, no such attempt is made in this study.

Kuravi, Ramachandra Srinivasa Chaitanya

2011-05-01T23:59:59.000Z

5

Kinetic viscoelasticity modeling applied to degradation during carbonľcarbon composite processing  

E-Print Network (OSTI)

Kinetic viscoelasticity modeling has been successfully utilized to describe phenomena during cure of thermoset based carbon fiber reinforced matrices. The basic difference from classic viscoelasticity is that the fundamental ...

Drakonakis, Vassilis M.

6

A Molecular Based Model for Polymer Viscoelasticity: Intra-and Inter-Molecular  

E-Print Network (OSTI)

A Molecular Based Model for Polymer Viscoelasticity: Intra- and Inter-Molecular Variability H viscoelasticity based on a stick-slip continuum molecular-based model. The model developed is a continuum tube-system is composed of long molecular chains. The dynamics of these molecular chains are developed by modeling them

7

A non-local, ordinary-state-based viscoelasticity model for peridynamics.  

SciTech Connect

A non-local, ordinary-state-based, peridynamics viscoelasticity model is developed. In this model, viscous effects are added to deviatoric deformations and the bulk response remains elastic. The model uses internal state variables and is conceptually similar to linearized isotropic viscolelasticity in the local theory. The modulus state, which is used to form the Jacobian matrix in Newton-Raphson algorithms, is presented. The model is shown to satisfy the 2nd law of thermodynamics and is applicable to problems in solid continuum mechanics where fracture and rate effects are important; it inherits all the advantages for modeling fracture associated with peridynamics. By combining this work with the previously published ordinary-state-based plasticity model, the model may be amenable to viscoplasticity problems where plasticity and rate effects are simultaneously important. Also, the model may be extended to include viscous effects for spherical deformations as well. The later two extensions are not presented and may be the subject of further work.

Mitchell, John Anthony

2011-10-01T23:59:59.000Z

8

Videogrammetric Model Deformation Measurement Technique  

Science Conference Proceedings (OSTI)

The theory, methods, and applications of the videogrammetric model deformation (VMD) measurement technique used at NASA for wind tunnel testing are presented. The VMD technique, based on non-topographic photogrammetry, can determine static and dynamic ...

Burner A. W.; Liu Tianshu

2001-07-01T23:59:59.000Z

9

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

E-Print Network (OSTI)

Modeling of the time-dependent behavior of cement paste has always been a difficulty. In the past, viscoelastic behavior of cementitious materials has been primarily attributed to the viscoelastic properties of C-S-H components. Recent experimental results show that C-S-H may not exhibit as much creep and relaxation as previously thought. This requires new consideration of different mechanisms leading to the viscoelastic behavior of cement paste. Thus the objective of this thesis is to build a 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 this thesis is that the apparent viscoelastic behavior due to dissolution of load bearing phases is substantial. The dissolution process occurring during the hydration reaction can change the stress distribution inside cementitious materials, resulting in an apparent viscoelastic behavior of the whole cementitious materials. This finding requires new consideration of mechanisms of time-dependent behavior of cementitious materials regarding the dissolution process of cement paste.

Li, Xiaodan

2012-05-01T23:59:59.000Z

10

Deformable human body model development  

SciTech Connect

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). A Deformable Human Body Model (DHBM) capable of simulating a wide variety of deformation interactions between man and his environment has been developed. The model was intended to have applications in automobile safety analysis, soldier survivability studies and assistive technology development for the disabled. To date, we have demonstrated the utility of the DHBM in automobile safety analysis and are currently engaged in discussions with the U.S. military involving two additional applications. More specifically, the DHBM has been incorporated into a Virtual Safety Lab (VSL) for automobile design under contract to General Motors Corporation. Furthermore, we have won $1.8M in funding from the U.S. Army Medical Research and Material Command for development of a noninvasive intracranial pressure measurement system. The proposed research makes use of the detailed head model that is a component of the DHBM; the project duration is three years. In addition, we have been contacted by the Air Force Armstrong Aerospace Medical Research Laboratory concerning possible use of the DHBM in analyzing the loads and injury potential to pilots upon ejection from military aircraft. Current discussions with Armstrong involve possible LANL participation in a comparison between DHBM and the Air Force Articulated Total Body (ATB) model that is the current military standard.

Wray, W.O.; Aida, T.

1998-11-01T23:59:59.000Z

11

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

E-Print Network (OSTI)

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 matrix as constituents. Polymer constituent exhibits time-dependent or inelastic responses, while particle constituent is linear elastic. Schapery's viscoelastic integral model is additively combined with a viscoplastic constitutive model. Two viscoplastic models are considered: Perzyna's model and Valanis's endochronic model. A unit-cell model with four particle and polymer sub-cells is generated to obtain homogenized responses of the particle-reinforced composites. A time-integration algorithm is formulated for solving the time-dependent and inelastic constitutive model for the isotropic polymers and nested to the unit-cell model of the particle composites. Available micromechanical models and experimental data in the literature are used to verify the proposed micromechanical model in predicting effective viscoelasticviscoplastic responses of particle-reinforced composites. Filler particles are added to enhance properties of the matrix in the fiber reinforced polymer (FRP) composites. The combined fiber and particle reinforced matrix forms a hybrid composite. The proposed micromechanical model of particle-reinforced composites is used to provide homogenized properties of the matrix systems, having filler particles, in the hybrid composites. Three-dimensional (3D) finite element (FE) models of composite's microstructures are generated for two hybrid systems having unidirectional long fiber and short fiber embedded in cubic matrix. The micromechanical model is implemented at the material (Gaussian) points of the matrix elements in the 3D FE models. The integrated micromechanical-FE framework is used to examine time-dependent and inelastic behaviors of the hybrid composites.

Kim, Jeong Sik

2009-12-01T23:59:59.000Z

12

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

E-Print Network (OSTI)

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 ...

Ober, Thomas J. (Thomas Joseph)

2010-01-01T23:59:59.000Z

13

Mathematical modeling of irreversible dynamic deformation, micro...  

National Nuclear Security Administration (NNSA)

proceed in deformable solids under intensive dynamic loading, consist of mechanical, thermal and structural ones, which correlate themselves. The structural processes involve the...

14

Modeling Of Surface Deformation From Satellite Radar Interferometry In The  

Open Energy Info (EERE)

Modeling Of Surface Deformation From Satellite Radar Interferometry In The Modeling Of Surface Deformation From Satellite Radar Interferometry In The Salton Sea Geothermal Field, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Paper: Modeling Of Surface Deformation From Satellite Radar Interferometry In The Salton Sea Geothermal Field, California Details Activities (1) Areas (1) Regions (0) Abstract: Surface deformation in the Salton Sea geothermal field is modeled using results from satellite radar interferometry, data from leveling surveys, and observations from the regional GPS network. The field is located in the Salton Trough, an active spreading center in southern California, which is traversed by the Brawley seismic zone. Deformation time series at thousands of points in the study area are obtained from a

15

Modeling Hot Mix Asphalt Compaction Using a Thermodynamics Based Compressible Viscoelastic Model within the Framework of Multiple Natural Configurations  

E-Print Network (OSTI)

Hot mix asphalt (HMA) is a composite material that exhibits a nonlinear response that is dependent on temperature, type of loading and strain level. The properties of HMA are highly influenced by the type and amount of the constituents used and also depend on its internal structure. In such a material the variable effects of the compaction process assume a central importance in determining material performance. It is generally accepted that the theoretical knowledge about material behavior during compaction is limited and it is therefore hard to predict and manage (the effect of) a compaction process. This work makes an attempt to address such a specific need by developing a continuum model that can be adapted for simulating the compaction of hot mix asphalt (HMA) using the notion of multiple natural configurations. A thermodynamic framework is employed to study the non-linear dissipative response associated with HMA by specifying the forms for the stored energy and the rate of dissipation function for the material; a viscoelastic compressible fluid model is developed using this framework to model the compaction of hot mix asphalt. It is further anticipated that the present work will aid in the development of better constitutive models capable of capturing the mechanics of processes like compaction both in the laboratory and in the field. The continuum model developed was implemented in the finite element method, which was employed to setup a simulation environment for hot mix asphalt compaction. The finite element method was used for simulating compaction in the laboratory and in various field compaction projects.

Koneru, Saradhi

2010-08-01T23:59:59.000Z

16

Storm Tracks and Barotropic Deformation in Climate Models  

Science Conference Proceedings (OSTI)

The relationship between the time-mean planetary-scale deformation field and the structure of midlatitude storm tracks is studied in wintertime simulations of the National Center for Atmospheric Research (NCAR) Community Climate Model and the ...

Robert X. Black; Randall M. Dole

2000-08-01T23:59:59.000Z

17

Meshless modeling of deformable shapes and their motion  

Science Conference Proceedings (OSTI)

We present a new framework for interactive shape deformation modeling and key frame interpolation based on a meshless finite element formulation. Starting from a coarse nodal sampling of an object's volume, we formulate rigidity and volume preservation ...

Bart Adams; Maks Ovsjanikov; Michael Wand; Hans-Peter Seidel; Leonidas J. Guibas

2008-07-01T23:59:59.000Z

18

Development of nonlinear analytical model and seismic analyses of a steel frame with self-centering devices and viscoelastic dampers  

Science Conference Proceedings (OSTI)

This paper highlights the role of advanced structural analysis tools on the conception of high-performance earthquake-resistant structural systems. A new steel frame equipped with self-centering devices and viscoelastic dampers is described. A prototype ... Keywords: Damage-free, High-performance, Seismic design, Self-centering, Steel MRF, Viscoelastic dampers

Theodore L. Karavasilis; Tony Blakeborough; Martin S. Williams

2011-06-01T23:59:59.000Z

19

Algebraic theory of linear viscoelastic nemattodynamics Part 2: Linear viscoelastic nematic viscoelasticity  

E-Print Network (OSTI)

This second part of paper develops a theory of linear viscoelastic nematodynamics applicable to LCP. The viscous and elastic nematic components in theory are described by using the LEP approach for viscous nematics and de Gennes free energy for weakly elastic nematic elastomers. The case of applied external magnetic field exemplifies the occurrence of non-symmetric stresses. In spite of multi- (10) parametric character of the theory, the use of nematic operators presents it in an elegant form. When the magnetic field is absent, the theory is simplified for symmetric case with 6 parameters, and takes an extremely simple, 2-parametric form for viscoelastic nematodynamics with possible soft deformation modes. It is shown that the linear nematodynamics is always reduced to the LEP-like equations where the coefficients are changed for linear memory functionals whose parameters are calculated from original viscosities and moduli.

Arkady I. Leonov

2004-09-10T23:59:59.000Z

20

Real-time deformable models for surgery simulation: a survey  

Science Conference Proceedings (OSTI)

Simulating the behaviour of elastic objects in real time is one of the current objectives of computer graphics. One of its fields of application lies in virtual reality, mainly in surgery simulation systems. In computer graphics, the models used for ... Keywords: Animation, Deformable model, Elasticity, Real time, Surgery simulation

U. Meier; O. Lˇpez; C. Monserrat; M. C. Juan; M. Alca˝iz

2005-03-01T23:59:59.000Z

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


21

Multiscale Modeling of Microstructure Deformation in Material ...  

Science Conference Proceedings (OSTI)

... a multi scale modelling approach combined with conventional material models ... Optimization of Thermal Cycle for Rails with Respect to the Wear Resistance.

22

Shape oscillations of a viscoelastic drop  

SciTech Connect

Small-amplitude axisymmetric shape deformations of a viscoelastic liquid drop in microgravity are theoretically analyzed. Using the Jeffreys constitutive equation for linear viscoelasticity, the characteristic equation for the frequency and decay factor of the shape oscillations is derived. Asymptotic analysis of this equation is performed in the low- and high-viscosity limits and for the cases of small, moderate, and large elasticities. Elastic effects are shown to give rise to a type of shape oscillation that does not depend on the surface tension. The existence of such oscillations is confirmed by numerical solution of the characteristic equation in various regimes. A method for determining the viscoelastic properties of highly viscous liquids based upon experimental measurements of the frequency and damping rate of such shape oscillations is suggested.

Khismatullin, Damir B.; Nadim, Ali

2001-06-01T23:59:59.000Z

23

Modeling of friction-induced deformation and microstructures.  

SciTech Connect

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.

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

24

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

E-Print Network (OSTI)

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, which are considered as linearly elastic with regards to their mechanical response, and isotropic polymeric matrix, which shows viscoelastic-viscoplastic response under various stresses and temperatures. Due to the viscoelastic and viscoplastic behavior of the polymeric matrix, the overall FRP composites exhibit a combined time-dependent and inelastic behavior. A simplified micromechanical model, consisting of a unit-cell with four fiber and matrix subcells, is formulated to homogenize the overall heat conduction and viscoelastic-viscoplastic responses of the FRP composites. The micromechanical model is compatible with a displacement based finite element (FE) and is implemented at the Gaussian integration points within the continuum finite elements, which is useful for analyzing the overall time-dependent response of FRP composite structures under various boundary conditions. The Schapery nonlinear integral model combined with the Perzyna viscoplastic model is used to describe the viscoelastic-viscoplastic response of the polymer constituents. An integrated time integration algorithm is formulated at the micromechanics level in order to solve the nonlinear viscoelastic-viscoplastic constitutive model at the matrix subcells and obtain the overall nonlinear response of the FRP. The viscoelastic-viscoplastic micromechanical model is validated usingexperimental data on off-axis glass/epoxy FRP composites available in literature. The overall response of the FRP composites determined from the simplified micromechanical model is also compared with the ones generated from microstructures of FRP with various fiber arrangements dispersed in homogeneous polymer matrix. The microstructural models of the FRP with detailed fiber arrangements are generated using FE. The effects 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 composites are studied using the two micromechanical models discussed above. Finally, an example of structural analysis is performed on a polymeric smart sandwich composite beam, having FRP skins and polymeric foam core with piezoelectric sensors integrated to the FRP skins, undergoing three point bending at an elevated temperature. The creep displacement is compared to experimental data available in literature.

Jeon, Jaehyeuk

2013-08-01T23:59:59.000Z

25

Antilinear deformations of Coxeter groups, an application to Calogero models  

E-Print Network (OSTI)

We construct complex root spaces remaining invariant under antilinear involutions related to all Coxeter groups. We provide two alternative constructions: One is based on deformations of factors of the Coxeter element and the other based on the deformation of the longest element of the Coxeter group. Motivated by the fact that non-Hermitian Hamiltonians admitting an antilinear symmetry may be used to define consistent quantum mechanical systems with real discrete energy spectra, we subsequently employ our constructions to formulate deformations of Coxeter models remaining invariant under these extended Coxeter groups. We provide explicit and generic solutions for the Schroedinger equation of these models for the eigenenergies and corresponding wavefunctions. A new feature of these novel models is that when compared with the undeformed case their solutions are usually no longer singular for an exchange of an amount of particles less than the dimension of the representation space of the roots. The simultaneous scattering of all particles in the model leads to anyonic exchange factors for processes which have no analogue in the undeformed case.

Andreas Fring; Monique Smith

2010-04-06T23:59:59.000Z

26

Analysis of deformable image registration accuracy using computational modeling  

SciTech Connect

Computer aided modeling of anatomic deformation, allowing various techniques and protocols in radiation therapy to be systematically verified and studied, has become increasingly attractive. In this study the potential issues in deformable image registration (DIR) were analyzed based on two numerical phantoms: One, a synthesized, low intensity gradient prostate image, and the other a lung patient's CT image data set. Each phantom was modeled with region-specific material parameters with its deformation solved using a finite element method. The resultant displacements were used to construct a benchmark to quantify the displacement errors of the Demons and B-Spline-based registrations. The results show that the accuracy of these registration algorithms depends on the chosen parameters, the selection of which is closely associated with the intensity gradients of the underlying images. For the Demons algorithm, both single resolution (SR) and multiresolution (MR) registrations required approximately 300 iterations to reach an accuracy of 1.4 mm mean error in the lung patient's CT image (and 0.7 mm mean error averaged in the lung only). For the low gradient prostate phantom, these algorithms (both SR and MR) required at least 1600 iterations to reduce their mean errors to 2 mm. For the B-Spline algorithms, best performance (mean errors of 1.9 mm for SR and 1.6 mm for MR, respectively) on the low gradient prostate was achieved using five grid nodes in each direction. Adding more grid nodes resulted in larger errors. For the lung patient's CT data set, the B-Spline registrations required ten grid nodes in each direction for highest accuracy (1.4 mm for SR and 1.5 mm for MR). The numbers of iterations or grid nodes required for optimal registrations depended on the intensity gradients of the underlying images. In summary, the performance of the Demons and B-Spline registrations have been quantitatively evaluated using numerical phantoms. The results show that parameter selection for optimal accuracy is closely related to the intensity gradients of the underlying images. Also, the result that the DIR algorithms produce much lower errors in heterogeneous lung regions relative to homogeneous (low intensity gradient) regions, suggests that feature-based evaluation of deformable image registration accuracy must be viewed cautiously.

Zhong Hualiang; Kim, Jinkoo; Chetty, Indrin J. [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan 48202 (United States)

2010-03-15T23:59:59.000Z

27

STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS  

SciTech Connect

The research under this project focused on a theoretical and computational modeling of dislocation dynamics of mesoscale deformation of metal single crystals. Specifically, the work aimed to implement a continuum statistical theory of dislocations to understand strain hardening and cell structure formation under monotonic loading. These aspects of crystal deformation are manifestations of the evolution of the underlying dislocation system under mechanical loading. The project had three research tasks: 1) Investigating the statistical characteristics of dislocation systems in deformed crystals. 2) Formulating kinetic equations of dislocations and coupling these kinetics equations and crystal mechanics. 3) Computational solution of coupled crystal mechanics and dislocation kinetics. Comparison of dislocation dynamics predictions with experimental results in the area of statistical properties of dislocations and their field was also a part of the proposed effort. In the first research task, the dislocation dynamics simulation method was used to investigate the spatial, orientation, velocity, and temporal statistics of dynamical dislocation systems, and on the use of the results from this investigation to complete the kinetic description of dislocations. The second task focused on completing the formulation of a kinetic theory of dislocations that respects the discrete nature of crystallographic slip and the physics of dislocation motion and dislocation interaction in the crystal. Part of this effort also targeted the theoretical basis for establishing the connection between discrete and continuum representation of dislocations and the analysis of discrete dislocation simulation results within the continuum framework. This part of the research enables the enrichment of the kinetic description with information representing the discrete dislocation systems behavior. The third task focused on the development of physics-inspired numerical methods of solution of the coupled dislocation kinetics and crystal mechanics framework. To a large extent, this task has also been successfully started. We have developed a custom finite-element approach with mesh points being a subset of the underlying crystal structure. When used to predict the evolution of the dislocation system, the planar motion of dislocations is naturally captured for all slip systems, thus minimizing numerical errors and providing simple ways to investigate cross slip and dislocation reactions. Preliminary results in this direction show that we are closer than ever in building a predictive framework for dislocation dynamics and mesoscale plasticity based on the first principles of dislocation dynamics. The rest of the report gives and overview of the research performed under this project and highlights the key results and open questions left for future investigations.

Anter El-Azab

2013-04-08T23:59:59.000Z

28

Kinematic models of interseismic deformation in Southern California  

E-Print Network (OSTI)

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 ...

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

2004-01-01T23:59:59.000Z

29

Some Anisotropic Viscoelastic Green Functions  

E-Print Network (OSTI)

In this paper, we compute the closed form expressions of elastody- namic Green functions for three different viscoelastic media with simple type of anisotropy. We follow Burridge et al. [Proc. Royal Soc. of London. 440(1910): (1993)] to express unknown Green function in terms of three scalar functions $\\phi_i$, by using the spectral decomposition of the Christoffel tensor associated with the medium. The problem of computing Green function is, thus reduced to the resolution of three scalar wave equations satisfied by $\\phi_i$, and subsequent equations with $\\phi_i$ as source terms. To describe viscosity effects, we choose an empirical power law model which becomes well known Voigt model for quadratic frequency losses.

Elie Bretin; Abdul Wahab

2011-02-19T23:59:59.000Z

30

Some Anisotropic Viscoelastic Green Functions  

E-Print Network (OSTI)

In this paper, we compute the closed form expressions of elastody- namic Green functions for three different viscoelastic media with simple type of anisotropy. We follow Burridge et al. [Proc. Royal Soc. of London. 440(1910): (1993)] to express unknown Green function in terms of three scalar functions $\\phi_i$, by using the spectral decomposition of the Christoffel tensor associated with the medium. The problem of computing Green function is, thus reduced to the resolution of three scalar wave equations satisfied by $\\phi_i$, and subsequent equations with $\\phi_i$ as source terms. To describe viscosity effects, we choose an empirical power law model which becomes well known Voigt model for quadratic frequency losses.

Bretin, Elie

2011-01-01T23:59:59.000Z

31

Mathematical modeling of irreversible dynamic deformation, micro- and macrofracture of materials and structures  

National Nuclear Security Administration (NNSA)

7: Material Phase Transition, Modeling, and Others 7: Material Phase Transition, Modeling, and Others Mathematical Modeling of Irreversible Dynamic Deformation, Micro- and Macrofracture of Materials and Structures P. P. Zakharov and A. B. Kiselev All-Russia Research Institute of Automatics, Moscow 125412, Russia Thermomechanical processes, which proceed in deformable solids under intensive dynamic loading, consist of mechanical, thermal and structural ones, which correlate themselves. The structural processes involve the formation, motion and interaction of defects in metallic crystals, phase transitions, the breaking of bonds between molecules in polymers, the accumulation of microstructural damages (pores, cracks), etc. Irreversible deformations, zones of adiabatic shear and microfractures are caused by these

32

A flow modeling of lubricating greases under shear deformation by cellular automata  

Science Conference Proceedings (OSTI)

A Cellular Automata modeling of the lubricating grease flow under the shear deformation is proposed Lubricating greases are composed of thickening agent, liquid lubricant and various kinds of additives The thickening agent forms fibrous microstructures ...

Shunsuke Miyamoto; Hideyuki Sakai; Toshihiko Shiraishi; Shin Morishita

2006-09-01T23:59:59.000Z

33

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

Science Conference Proceedings (OSTI)

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.

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

34

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

SciTech Connect

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

Shouchun Deng; Robert Podgorney; Hai Huang

2011-02-01T23:59:59.000Z

35

Modeling the compressive deformation of metal micro-textured thermal interface materials using SEM geometry reconstruction  

Science Conference Proceedings (OSTI)

Idealized and simplified geometries are commonly used in finite element models to ease model creation and meshing. However, at smaller length-scales, the influence of geometrical imperfections and defects can significantly affect the accuracy of the ... Keywords: Buckling, Finite element modeling, Metal micro-textured thermal interface materials, Plastic deformation, SEM stereomicroscopy, Surface reconstruction

R. Kempers; P. Ahern; A. J. Robinson; A. M. Lyons

2012-02-01T23:59:59.000Z

36

Genus one correction to Seiberg-Witten prepotential from \\beta-deformed matrix model  

E-Print Network (OSTI)

We study \\beta-deformed matrix models with Penner type potentials, which correspond to N=2 SU(2) supersymmetric gauge theories with N_F=2,3, and 4 flavors. We compute explicitly the genus one corrections to the free energy of the matrix model and show that they match the corresponding results obtained from the Nekrasov partition function.

Baek, Jong-Hyun

2013-01-01T23:59:59.000Z

37

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

E-Print Network (OSTI)

Interest in evaluating the performance and safety of offshore oil and gas platforms has been expanding due to the growing world energy supply and recent offshore catastrophes. In order to accurately assess the reliability of an offshore platform, all relevant uncertainties must be properly accounted for. This necessitates the development of a probabilistic demand model that accounts for the relevant uncertainties and model errors. In this study, a probabilistic demand model is developed 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. The correction terms are developed to capture the bias inherent in the deterministic model. The model error is developed to capture the accuracy of the model. The correction terms and model errors are estimated through a Bayesian approach using simulation data obtained from detailed dynamic analyses of a set of representative asymmetric offshore platform configurations. The proposed demand model provides accurate and unbiased estimates of the deformation demand on offshore jacket platforms. The developed probabilistic demand model is then used to assess the reliability of a typical offshore platform considering serviceability and ultimate performance levels. In addition, a sensitivity analysis is conducted to assess the effect of key parameters on the results of the analyses. The proposed demand model can be used to assess the reliability of different design options and for the reliability-based optimal design of offshore jacket platforms.

Fallon, Michael

2012-12-01T23:59:59.000Z

38

A Phase-Field Model for Deformation Twinning  

Science Conference Proceedings (OSTI)

First Principles Modeling of Shape Memory Alloy Magnetic Refrigeration Materials ... of Lithium Battery Materials LiMPO4 (M = Mn, Fe, Co, and Ni): A Comparative ... Forming-Crush Simulation Optimization Using Internal State Variable Model.

39

Multi-scale Modeling of Microstructure Deformation in Material ...  

Science Conference Proceedings (OSTI)

Modeling Metal Powder Compaction Using Combined Finite and Discrete .... Optimization of Thermal Cycle for Rails with Respect to the Wear Resistance:á...

40

Recovery of Soft Tissue Object Deformation from 3D Image Sequences Using Biomechanical Models  

Science Conference Proceedings (OSTI)

The estimation of soft tissue deformation from 3D image sequences is an important problem in a number of fields such as diagnosis of heart disease and image guided surgery. In this paper we describe a methodology for using biomechanical material models, ...

Xenophon Papademetris; Pengcheng Shi; Donald P. Dione; Albert J. Sinusas; R. Todd Constable; James S. Duncan

1999-06-01T23:59:59.000Z

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


41

Segmentation of female pelvic organs in axial magnetic resonance images using coupled geometric deformable models  

Science Conference Proceedings (OSTI)

The segmentation of pelvic structures in magnetic resonance (MR) images of the female pelvic cavity is a challenging task. This paper proposes the use of three novel geometric deformable models to segment the bladder, vagina and rectum in axial MR images. ... Keywords: Bladder, Image segmentation, Imaging appearance, Level set, Prior shape knowledge, Rectum, Vagina

Zhen Ma; Renato M. Natal Jorge; Teresa Mascarenhas; JoŃO Manuel R. S. Tavares

2013-05-01T23:59:59.000Z

42

Three-Dimensional Face Recognition in the Presence of Facial Expressions: An Annotated Deformable Model Approach  

Science Conference Proceedings (OSTI)

In this paper, we present the computational tools and a hardware prototype for 3D face recognition. Full automation is provided through the use of advanced multistage alignment algorithms, resilience to facial expressions by employing a deformable model ... Keywords: Face and gesture recognition, information search and retrieval.

Ioannis A. Kakadiaris; Georgios Passalis; George Toderici; Mohammed N. Murtuza; Yunliang Lu; Nikos Karampatziakis; Theoharis Theoharis

2007-04-01T23:59:59.000Z

43

CFD Modeling of Fluid Flow Behavior and Bath Surface Deformation ...  

Science Conference Proceedings (OSTI)

Direct Numerical Simulation of Inclusion Turbulent Deposition at Liquid ... Flow and Shrinkage Pipe Formation on Macrosegregation of Investment Cast -TiAl Alloys ... Numerical Modeling of the Interaction between a Foreign Particle aná...

44

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

E-Print Network (OSTI)

in the cell distance is 170┬Ám. Keywords: PV module, Encapsulation, Simulation, Reliability, Mechanics 1THERMOMECHANICS OF PV MODULES INCLUDING THE VISCOELASTICITY OF EVA Ulrich Eitner1, *, Matthias by a comparison to displacement experiments where the thermomechanical deformation of solar cells in a PV laminate

45

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

Science Conference Proceedings (OSTI)

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

Reaugh, J E

2011-11-22T23:59:59.000Z

46

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

SciTech Connect

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

Reaugh, J E

2011-11-22T23:59:59.000Z

47

Cap plasticity models and compactive and dilatant pre-failure deformation  

SciTech Connect

At low mean stresses, porous geomaterials fail by shear localization, and at higher mean stresses, they undergo strain-hardening behavior. Cap plasticity models attempt to model this behavior using a pressure-dependent shear yield and/or shear limit-state envelope with a hardening or hardening/softening elliptical end cap to define pore collapse. While these traditional models describe compactive yield and ultimate shear failure, difficulties arise when the behavior involves a transition from compactive to dilatant deformation that occurs before the shear failure or limit-state shear stress is reached. In this work, a continuous surface cap plasticity model is used to predict compactive and dilatant pre-failure deformation. During loading the stress point can pass freely through the critical state point separating compactive from dilatant deformation. The predicted volumetric strain goes from compactive to dilatant without the use of a non-associated flow rule. The new model is stable in that Drucker's stability postulates are satisfied. The study has applications to several geosystems of current engineering interest (oil and gas reservoirs, nuclear waste repositories, buried targets, and depleted reservoirs for possible use for subsurface sequestration of greenhouse gases).

FOSSUM,ARLO F.; FREDRICH,JOANNE T.

2000-02-17T23:59:59.000Z

48

arXiv:cond-mat/0608134v15Aug2006 Capillary wave dynamics on supported viscoelastic films: Single and double layers  

E-Print Network (OSTI)

? The fluid deformations generated by capillary waves store energy in the fluid in- terface and reported by Lal and collaborators. In sec- tion III we calculate the dynamics of the single supported fluid, for viscoelastic fluids, in the bulk as well. When these deformations relax, this energy is dissipated through

Levine, Alex J.

49

Three-Dimensional Modeling of Shape Memory Polymers Considering Finite Deformations and Heat Transfer  

E-Print Network (OSTI)

Shape memory polymers (SMPs) are a relatively new class of active materials that can store a temporary shape and return to the original configuration upon application of a stimulus such as temperature. This shape changing ability has led to increased interest in their use for biomedical and aerospace applications. A major challenge, however, in the advancement of these applications is the ability to accurately predict the material behavior for complex geometries and boundary conditions. This work addresses this challenge by developing an experimentally calibrated and validated constitutive model that is implemented as a user material subroutine in Abaqus ? a commercially available finite element software package. The model is formulated in terms of finite deformations and assumes the SMP behaves as a thermoelastic material, for which the response is modeled using a compressible neo-Hookean constitutive equation. An internal state variable, the glassy volume fraction, is introduced to account for the phase transformation and associated stored deformation upon cooling from the rubbery phase to the glassy phase and subsequently recovered upon heating. The numerical implementation is performed such that a system of equations is solved using a Newton-Raphson method to find the updated stress in the material. The conductive heat transfer is incorporated through solving Fourier's law simultaneously with the constitutive equations. To calibrate and validate the model parameters, thermomechanical experiments are performed on an amorphous, thermosetting polyurethane shape memory polymer. Strains of 10-25% are applied and both free recovery (zero load) and constrained displacement recovery boundary conditions are considered for each value of applied strain. Using the uniaxial experimental data, the model is then calibrated and compared to the 1-D experimental results. The validated finite element analysis tool is then used to model biomedical devices, including cardiovascular tubes and thrombectomy devices, fabricated from shape memory polymers. The effects of heat transfer and complex thermal boundary conditions are evaluated using coupled thermal-displacement analysis, for which the thermal material properties were experimentally calibrated.

Volk, Brent 1985-

2012-12-01T23:59:59.000Z

50

Viscoelastic properties of confined molecular layers Alois Wrger  

E-Print Network (OSTI)

- canol [17] reported a modulation of viscoelastic response, with a period corresponding to the molecular

Paris-Sud XI, Universit├ę de

51

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

SciTech Connect

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.

Turner, Daniel Zack

2012-01-01T23:59:59.000Z

52

A deformation and thermodynamic model for hydride precipitation kinetics in spent fuel cladding  

DOE Green Energy (OSTI)

Hydrogen is contained in the Zircaloy cladding of spent fuel rods from nuclear reactors. All the spent fuel rods placed in a nuclear waste repository will have a temperature history that decreases toward ambient; and as a result, most all of the hydrogen in the Zircaloy will eventually precipitate as zirconium hydride platelets. A model for the density of hydride platelets is a necessary sub-part for predicting Zircaloy cladding failure rate in a nuclear waste repository. A model is developed to describe statistically the hydride platelet density, and the density function includes the orientation as a physical attribute. The model applies concepts from statistical mechanics to derive probable deformation and thermodynamic functionals for cladding material response that depend explicitly on the hydride platelet density function. From this model, hydride precipitation kinetics depend on a thermodynamic potential for hydride density change and on the inner product of a stress tensor and a tensor measure for the incremental volume change due to hydride platelets. The development of a failure response model for Zircaloy cladding exposed to the expected conditions in a nuclear waste repository is supported by the US DOE Yucca Mountain Project. 19 refs., 3 figs.

Stout, R.B.

1989-10-01T23:59:59.000Z

53

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

E-Print Network (OSTI)

Problems involving coupled thermo-poro-chemo-mechanical processes are of great importance in geothermal and petroleum reservoir systems. In particular, economic power production from enhanced geothermal systems, effective water-flooding of petroleum reservoirs, and stimulation of gas shale reservoirs are significantly influenced by coupled processes. During such procedures, stress state in the reservoir is changed due to variation in pore fluid pressure and temperature. This can cause deformation 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 challenges and numerical difficulties. In this study, we develop and apply efficient numerical models to solve 3D injection/extraction geomechanics problems formulated within the framework of thermo-poro-mechanical theory with reactive flow. The models rely on combining Displacement Discontinuity (DD) Boundary Element Method (BEM) and Finite Element Method (FEM) to solve the governing equations of thermo-poro-mechanical processes involving fracture/reservoir matrix. The integration of BEM and FEM is accomplished through direct and iterative procedures. In each case, the numerical algorithms are tested against a series of analytical solutions. 3D study of fluid injection and extraction into the geothermal reservoir illustrates that thermo-poro-mechanical processes change fracture aperture (fracture conductivity) significantly and influence the fluid flow. Simulations that consider joint stiffness heterogeneity show development of non-uniform flow paths within the crack. Undersaturated fluid injection causes large silica mass dissolution and increases fracture aperture while supersaturated fluid causes mineral precipitation and closes fracture aperture. Results show that for common reservoir and injection conditions, the impact of fully developed thermoelastic effect on fracture aperture tend to be greater compare to that of poroelastic effect. Poroelastic study of hydraulic fracturing demonstrates that large pore pressure increase especially during multiple hydraulic fracture creation causes effective tensile stress at the fracture surface and shear failure around the main fracture. Finally, a hybrid BEFEM model is developed to analyze stress redistribution in the overburden and within the reservoir during fluid injection and production. Numerical results show that fluid injection leads to reservoir dilation and induces vertical deformation, particularly near the injection well. However, fluid withdrawal causes reservoir to compact. The Mandel-Cryer effect is also successfully captured in numerical simulations, i.e., pore pressure increase/decrease is non-monotonic with a short time values that are above/below the background pore pressure.

Rawal, Chakra

2012-05-01T23:59:59.000Z

54

Improving verification accuracy by synthesis of locally enhanced biometric images and deformable model  

Science Conference Proceedings (OSTI)

In this paper, we propose a 2-stage preprocessing framework which consists of image enhancement and deformation techniques to increase the verification performance of image-based biometric systems. In the preprocessing framework, first the quality of ... Keywords: Deformation, Face recognition, Iris recognition, Phase congruency, Quality enhancement, Support vector machine

Richa Singh; Mayank Vatsa; Afzel Noore

2007-11-01T23:59:59.000Z

55

Deformation and orientation effects in the driving potential of the dinuclear model  

E-Print Network (OSTI)

A double-folding method is used to calculate the nuclear and Coulomb interaction between two deformed nuclei with arbitrary orientations. A simplified Skryme-type interaction is adopted. The contributions of nuclear interaction and Coulomb interaction due to the deformation and orientation of the nuclei are evaluated for the driving potential used in the description of heavy-ion fusion reaction. So far there is no satisfactory theory to describe the evolution of the dynamical nuclear deformation and orientations during the heavy-ion fusion process. Our results estimated the magnitude of above effects.

Qingfeng Li; Wei Zuo; Wenfei Li; Nan Wang; Enguang Zhao; Junqing Li; W. Scheid

2005-04-22T23:59:59.000Z

56

Deformation of half-BPS solution in ABJM model and instability of supermembrane  

E-Print Network (OSTI)

It is well-known that a supermembrane in the light-cone gauge has a continuous spectrum and is unstable. Physical interpretation of this instability is that a supermembrane can have a long thin tube without cost of energy and consequently it becomes a spiky configuration in which multiple membranes are connected by thin tubes. On the other hand, the ABJM model was proposed as a low-energy description of multiple M2-branes in the static gauge. It is natural that an M2-brane is also unstable in this gauge if we believe the physical picture in the light-cone gauge. In order to examine this, we construct a BPS solution explicitly both in the Nambu-Goto action of a supermembrane in the static gauge and in the U(1){\\times}U(1) ABJM model, which represents intersecting M2-branes. Since this configuration is regarded as a single M2-brane emitting another one, we study the instability of an M2-brane by analyzing fluctuations around it. We show that a zero mode exists which can deform the configuration. For comparison, we also examine a similar configuration on the D2-brane and check that it does not have such zero modes under a fixed string charge. Furthermore we confirm that the novel Higgs mechanism translates our BPS solution in the ABJM model into that in the D2-brane world volume theory, where the winding number of the former around the fixed point of the orbifold becomes the number of strings ending on the D2-brane in the latter.

Tsunehide Kuroki; Akitsugu Miwa; Satoshi Okuda

2011-02-16T23:59:59.000Z

57

Modeling the High-Frequency Component of Arctic Sea Ice Drift and Deformation  

Science Conference Proceedings (OSTI)

Buoy observations of sea ice drift show that sea ice motion and deformation contain substantial high-frequency variability at subdaily timescales. However, numerical simulations of the sea ice dynamics normally do not include processes on such ...

Petra Heil; William D. Hibler III

2002-11-01T23:59:59.000Z

58

Considerations for developing models of multiphase flow in deformable porous media.  

Science Conference Proceedings (OSTI)

This document summarizes research and planning for the development of a numerical simulation capability for nonisothermal multiphase, multicomponent transport in heterogeneous deformable porous materials. Particular attention is given to describing a mathematical formulation for flow in deformable media and for numerical techniques for dealing with phase transitions. A development plan is formulated to provide a computational capability motivated by current and future needs in geosystems management for energy security.

Martinez, Mario J.; Stone, Charles Michael

2008-09-01T23:59:59.000Z

59

Weak Viscoelastic Nematodynamics of Maxwell Type  

E-Print Network (OSTI)

A constitutive theory for weak viscoelastic nematodynamics of Maxwell type is developed using the standard local approach of non-equilibrium thermodynamics. Along with particular viscoelastic and nematic kinematics, the theory uses the weakly elastic potential proposed by de Gennes for nematic solids and the LEP constitutive equations for viscous nematic liquids, while ignoring the Frank (orientation) elasticity and inertia effects. In spite of many basic parameters, algebraic properties of nematic operations investigated in Appendix, allowed us to reveal a general group structure of the theory and present it in a simple form. It is shown that the evolution equation for director is also viscoelastic. An example of magnetization clarifies the situation with non-symmetric stresses. When the sources of stress asymmetry are absent, the theory is simplified and its relaxation properties are described by a symmetric subgroup of nematic algebraic operations. A purely linear constitutive behavior exemplifies the symmetric situation.

Arkady I. Leonov; Valery S. Volkov

2004-08-26T23:59:59.000Z

60

Viscoelastic Study Using an Atomic Force Microscope Modified to Operate as a Nanorheometer  

E-Print Network (OSTI)

software interface. Measurements on an agar gel model substrate reveal a viscoelastic response that is well, considering the cantilever assembly instead as a load transducer, one can study the rheological behavior. Their approaches fall into the following general categories: (I) analysis of conventional force-distance curves,10

Attard, Phil

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


61

The role of viscoelastic contrast in orientation selection of block copolymer lamellar phases under oscillatory shear  

E-Print Network (OSTI)

The mesoscale rheology of a lamellar phase of a block copolymer is modeled as a structured fluid of uniaxial symmetry. The model predicts a viscoelastic response that depends on the angle between the the local lamellar planes and velocity gradients. We focus on the stability under oscillatory shear of a two layer configuration comprising a parallel and a perpendicularly oriented domain, so that the two layers have a different viscoelastic modulus $G^{*}(\\omega)$. A long wave, low Reynolds number expansion is introduced to analytically obtain the region of stability. When the response of the two layers is purely viscous, we recover earlier results according to which the interface is unstable for non zero Reynolds number flows when the thinner layer is more viscous. On the other hand, when viscoelasticity is included, we find that the interface can become unstable even for zero Reynolds number. The interfacial instability is argued to dynamically favor perpendicular relative to parallel orientation, and hence we suggest that the perpendicular orientation would be selected in a multi domain configuration in the range of frequency $\\omega$ in which viscoelastic contrast among orientations is appreciable.

Chi-Deuk Yoo; Jorge Vinals

2013-01-10T23:59:59.000Z

62

Application of Elliott's SU(3) model to the triaxially deformed harmonic oscillators  

SciTech Connect

We have introduced new bosons corresponding to the integral ratio of three frequencies for a harmonic oscillator potential, by means of a non-linear transformation which realizes the SU(3) group as a dynamical symmetry group, and which leaves the anisotropic harmonic oscillator Hamiltonian invariant. The classification of the single-particle levels based on this covering group predicts magic numbers depending on the deformation parameters {delta} and {gamma}. The special cases with tan {gamma} = 1/{radical}(3)({gamma} = 30 deg.) and {radical}(3)/5({gamma}{approx}19 deg.) are discussed.

Sugawara-Tanabe, Kazuko [Otsuma Women's University, Tama, Tokyo 206-8540 (Japan); Theoretical Nuclear Physics Laboratory, RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan)

2011-05-06T23:59:59.000Z

63

1D simulation of polymer flooding including the viscoelastic effect of polymer solution  

Science Conference Proceedings (OSTI)

This paper reports that simple simulation models are constructed to predict the performance of 1D polymer flooding. In the models, two phases of oil and polymer solution were assumed to be immiscible with each other. Because the displacing fluid was non-Newtonian, the Buckley-Leverett equation could be modified and a new approach developed to calculate fractional-flow curves. The rheological behavior of polymer solution was modeled with an Ellis type model and a viscoelastic model. To verify the models, two 1D flooding experiments were carried out on 2.8-cm-diameter, 47-cm-long, unconsolidated cores packed with glass beads (70/100 mesh). Porosities of the cores are about 37% and permeabilities are around 26{mu}m{sup 2}. Two white mineral oils of viscosities 25 and 60 mPa {center dot} s and a 200-ppm polyacrylamide solution were used. In each experiment, polymer flooding was done after waterflooding. Initial water saturation was controlled to be almost the same at the start of each flood. The calculated polymer-flooding performances were compared with experimental data. On the other hand, the viscoelastic model predicted fractional-flow curves, oil recovery performances, and breakthrough times of the experiments very well. The viscoelastic effect of polymer solution is thought to play an important role in the improvement of oil recovery.

Masuda, Y.; Tang, K.C.; Miyazawa, M.; Tanaka, S. (Univ. of Tokyo (JP))

1992-05-01T23:59:59.000Z

64

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

E-Print Network (OSTI)

Modules for cotton storage and transport should be constructed with a shape that will resist collecting water to maintain the quality of seed cotton during storage. Meeting this specification requires knowledge of the relationship between the applied compressive force, deformation, and time for seed cotton. Several factors were tested to determine their effects on the height and density of seed cotton during compression, creep loading, and recovery. Models were used to describe these processes. These results were used to develop an algorithm capable of providing information on module shape to the module builder operator. The initial loading density did not affect the compressed density, but a slight effect was observed in the recovered density, due to the weight of the seed cotton. Picker harvested cotton was compressed to a greater density than stripper harvested cotton, but expanded more during recovery, resulting in similar final densities. Multiple compressions increased the density, but this increase was not physically significant after the third compression. Higher moisture content increased the density seed cotton could be compressed to slightly. Viscoelastic behavior was observed; however, the effect on density was small. Both the compression and creep curves were described using mathematical models. A compression model using an asymptotic true strain measure yielded high R2 values; however, some aspect of this process remained unexplained and the equation was limited in its predictive ability. Creep behavior was described using a modified Burgers model. This model was more accurate than the creep model, although a definite trend existed in the creep model residuals. A feedback algorithm was developed based on the observation that the compressed density was primarily dependent on the mass of seed cotton and not the initial density. By measuring the compressed depth of cotton in a module and the hydraulic pressure of the tramper foot cylinder, the resulting shape of the module can be predicted. Improved loading of the module builder is necessary to produce a desirably shaped module. More seed cotton needs to be placed in the center of the module, resulting in a surface that slopes down towards the outer edges.

Hardin, Robert Glen

2004-08-01T23:59:59.000Z

65

Rheology of human blood plasma: Viscoelastic versus Newtonian behavior  

E-Print Network (OSTI)

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.

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

2013-02-17T23:59:59.000Z

66

Using Nanotechnology in Viscoelastic Surfactant Stimulation Fluids  

E-Print Network (OSTI)

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 on the charge of the head group, salt concentration, temperature, and the presence of other interacting components. The problem with these fluids is that they are expensive and used at temperatures less than 200░F. The viscoelasticity of nanoparticle-networked VES fluid systems were analyzed in an HP/HT viscometer. A series of rheology experiments have been performed by using 2-4 vol% amidoamine oxide surfactant in 13 to 14.2 ppg CaBr2 brines and 10.8 to 11.6 ppg CaCl2 brines at different temperatures up to 275░F and a shear rate of 10 s-1. The nanoparticles evaluated were MgO and ZnO at 6 pptg concentration. In addition, the effect of different nanoparticle concentrations (0.5 to 8 pptg) and micron size particles on the viscosity of VES fluid was investigated. The oscillatory shear rate sweep (100 to 1 s-1) was performed from 100 to 250░F. The effect of fish oil as an internal breaker on the viscosity of VES micelles was examined. This study showed that the addition of nanoparticles improved the thermal stability of VES micellar structures in CaBr2 and CaCl2 brines up to 275░F and showed an improved viscosity yield at different shear rates. Micro- and nanoparticles have potential to improve the viscosity of VES fluids. Lab tests show that for VES micellar systems without nanoparticles, the dominant factor is the storage modulus but when nanoparticles are added to the system at 275░F the loss modulus becomes the dominant factor. These positive effects of nanoparticles on VES fluid characteristics suggest that these particles can reduce treatment cost and will exceed temperature range to 275░F. With this work, we hope to have better understanding of nanoparticle/viscoelastic surfactant interaction.

Gurluk, Merve 1986-

2012-12-01T23:59:59.000Z

67

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

Science Conference Proceedings (OSTI)

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.

Cappa, F.; Rutqvist, J.

2010-06-01T23:59:59.000Z

68

Big Deformation in 17C  

E-Print Network (OSTI)

Reaction- and interaction cross sections of 17C on a carbon target have been reanalyzed by use of the modified Glauber model. The analysis with a deformed Woods-Saxon density/potential suggests a big deformation structure for 17C. The existence of a tail in the density distribution supports its possibility of being a one-neutron halo structure. Under a deformed core plus single-particle assumption, analysis shows a dominant d-wave of the valence neutron in 17C. Key words Cross section, Glauber model, Density distribution, Halo, Deformation.

Fan Guang-Wei; Cai Xiao-Lu; M. Fukuda; Han Ti-Fei; Li Xue-Chao; Ren Zhong-Zhou; Xu Wang

2013-05-01T23:59:59.000Z

69

Nonlinear viscoelastic dynamics of nano-confined water  

E-Print Network (OSTI)

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.

Tai-De Li; Elisa Riedo

2007-07-17T23:59:59.000Z

70

Spatial transfer functions: a unified approach to specifying deformation in volume modeling and animation  

Science Conference Proceedings (OSTI)

In this paper, we introduce the concept of spatial transfer functions as a unified approach to volume modeling and animation. A spatial transfer function is a function that defines the geometrical transformation of a scalar field in space, and is a generalization ...

M. Chen; D. Silver; A. S. Winter; V. Singh; N. Cornea

2003-07-01T23:59:59.000Z

71

A simple model for the quenching of pairing correlations effects in rigidly deformed rotational bands  

E-Print Network (OSTI)

Using Chandrasekhar's S-type coupling between rotational and intrinsic vortical modes one may simply reproduce the HFB dynamical properties of rotating nuclei within Routhian HF calculations free of pairing correlations yet constrained on the relevant so-called Kelvin circulation operator. From the analogy between magnetic and rotating systems, one derives a model for the quenching of pairing correlations with rotation, introducing a critical angular velocity -- analogous to the critical field in supraconductors -- above which pairing vanishes. Taking stock of this usual model, it is then shown that the characteristic behavior of the vortical mode angular velocity as a function of the global rotation angular velocity can be modelised by a simple two parameter formula, both parameters being completely determined from properties of the band-head (zero-spin) HFB solution. From calculation in five nuclei, the validity of this modelised Routhian approach is assessed. It is clearly shown to be very good in cases where the evolution of rotational properties is only governed by the coupling between the global rotation and the pairing-induced intrinsic vortical currents. It therefore provides a sound ground base for evaluating the importance of coupling of rotation with other modes (shape distortions, quasiparticle degrees of freedom).

P. Quentin; H. Laftchiev; D. Samsoen; I. N. Mikhailov

2003-07-25T23:59:59.000Z

72

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

E-Print Network (OSTI)

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 ...

Beese, Allison M

2011-01-01T23:59:59.000Z

73

Formation of deformation textures in face-centered-cubic materials studied by in-situ high-energy x-ray diffraction and self-consistent model.  

Science Conference Proceedings (OSTI)

The evolution of deformation textures in copper and a brass that are representative of fcc metals with different stacking fault energies (SFEs) during cold rolling is predicted using a self-consistent (SC) model. The material parameters used for describing the micromechanical behavior of each metal are determined from the high-energy X-ray (HEXRD) diffraction data. At small reductions, a reliable prediction of the evolution of the grain orientation distribution that is represented as the continuous increase of the copper and brass components is achieved for both metals when compared with the experimental textures. With increasing deformation, the model could characterize the textures of copper, i.e., the strengthening of the copper component, when dislocation slip is still the dominant mechanism. For a brass at moderate and large reductions, a reliable prediction of its unique feature of texture evolution, i.e., the weakening of the copper component and the strengthening of the brass component, could only be achieved when proper boundary conditions together with some specified slip/twin systems are considered in the continuum micromechanics mainly containing twinning and shear banding. The present investigation suggests that for fcc metals with a low SFE, the mechanism of shear banding is the dominant contribution to the texture development at large deformations.

Jia, N.; Nie, Z. H.; Ren, Y.; Peng, R. L.; Wang, Y. D.; Zhao, X.; X-Ray Science Division; Northeastern Univ.; Linkoping Univ.; Beijing Inst. of Tech.

2010-05-01T23:59:59.000Z

74

Modeling crustal deformation and rupture processes related to upwelling of deep CO2-rich fluids during the 1965-1967 Matsushiro Earthquake Swarm in Japan  

Science Conference Proceedings (OSTI)

In Matsushiro, central Japan, a series of more than 700,000 earthquakes occurred over a 2-year period (1965-1967) associated with a strike-slip faulting sequence. This swarm of earthquakes resulted in ground surface deformations, cracking of the topsoil, and enhanced spring-outflows with changes in chemical compositions as well as carbon dioxide (CO{sub 2}) degassing. Previous investigations of the Matsushiro earthquake swarm have suggested that migration of underground water and/or magma may have had a strong influence on the swarm activity. In this study, employing coupled multiphase flow and geomechanical modelling, we show that observed crustal deformations and seismicity can have been driven by upwelling of deep CO{sub 2}-rich fluids around the intersection of two fault zones - the regional East Nagano earthquake fault and the conjugate Matsushiro fault. We show that the observed spatial evolution of seismicity along the two faults and magnitudes surface uplift, are convincingly explained by a few MPa of pressurization from the upwelling fluid within the critically stressed crust - a crust under a strike-slip stress regime near the frictional strength limit. Our analysis indicates that the most important cause for triggering of seismicity during the Matsushiro swarm was the fluid pressurization with the associated reduction in effective stress and strength in fault segments that were initially near critically stressed for shear failure. Moreover, our analysis indicates that a two order of magnitude permeability enhancement in ruptured fault segments may be necessary to match the observed time evolution of surface uplift. We conclude that our hydromechanical modelling study of the Matsushiro earthquake swarm shows a clear connection between earthquake rupture, deformation, stress, and permeability changes, as well as large-scale fluid flow related to degassing of CO{sub 2} in the shallow seismogenic crust. Thus, our study provides further evidence of the important role of deep fluid sources in earthquake fault dynamics and surface deformations.

Cappa, F.; Rutqvist, J.; Yamamoto, K.

2009-05-15T23:59:59.000Z

75

Viscoelastic Timoshenko Beams with Occasionally Constant Relaxation Functions  

SciTech Connect

For a prescribed desirable arbitrary decay suitable viscoelastic materials are determined through their relaxation functions. It is shown that if we wish to have a decay of order {gamma}(t) then the kernels should be of the same order. That is their product with this function should be summable.

Tatar, Nasser-eddine, E-mail: tatarn@kfupm.edu.sa [King Fahd University of Petroleum and Minerals, Department of Mathematics and Statistics (Saudi Arabia)

2012-08-15T23:59:59.000Z

76

Deformation Mechanisms  

Science Conference Proceedings (OSTI)

Table 2┬á┬á┬áGrain-boundary-sliding models accommodated by dislocation motion ( Eq 9 )...D IPB . ¤? 0 is ignored for region II. 41 Bardeen-Herring source 480 The creation of dislocations on a solute-free mantle

77

Vortex-Driven Sensitivity in Deformation Flow  

Science Conference Proceedings (OSTI)

A sensitivity mechanism for the interaction of two vortices in a two-dimensional deformation background flow is explored. A nonlinear model describing the vortex interaction up to a critical merging distance is developed. This model shows that in ...

Zhiyuan Liu; Paul J. Roebber

2008-12-01T23:59:59.000Z

78

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

Science Conference Proceedings (OSTI)

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

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

2010-07-01T23:59:59.000Z

79

An extended finite element method for hydraulic fracture propagation in deformable porous media with the cohesive crack model  

Science Conference Proceedings (OSTI)

In this paper, a fully coupled numerical model is developed for the modeling of the hydraulic fracture propagation in porous media using the extended finite element method in conjunction with the cohesive crack model. The governing equations, which account ... Keywords: Cohesive crack propagation, Fluid flow, Fracturing porous media, Fully coupled model, Hydraulic fracturing, XFEM

T. Mohammadnejad, A. R. Khoei

2013-10-01T23:59:59.000Z

80

Deformed Einstein Gravity  

Science Conference Proceedings (OSTI)

We introduce the necessary concepts for an algebraic construction of a gravity theory on noncommutative spaces. The ??deformed diffeomorphisms are studied and a tensor calculus is defined. This leads to a deformed Einstein?Hilbert action which is invariant with respect to deformed diffeomorphisms. The dynamical variable is the vierbein field. The deformed action is a deformation of the usual Einstein?Hilbert action and reduces to it in the limit where the noncommutativity vanishes. This contribution is based on joint work with P. Aschieri

Frank Meyer

2006-01-01T23:59:59.000Z

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


81

Long-term deformational simulation of PC bridges based on the thermo-hygro model of micro-pores in cementitious composites  

Science Conference Proceedings (OSTI)

Creep deflections that greatly exceed the predicted values by the linear creep law are being found in measurements on actual PC bridge viaducts. In this study, structural creep deformations were reproduced by using the multi-scale coupled thermo-hygro and mechanical modeling which enables to deal with an interaction of chemo-physical events of differing dimensions ranging from the kinematics of moisture in micro-pores to the macroscopic structural mechanics, and the effect of various factors was analytically investigated. The numerical analysis approximately reproduced the excessive deflection measured on an actual bridge viaduct. It was confirmed that the creep bending of the viaduct having the hollow cross-section varies significantly due to the ambient temperature, humidity and the structural specific surface area. The macroscopic structural responses in association with the thermodynamic state of moisture in the micro-pores are also discussed.

Maekawa, Koichi, E-mail: Maekawa@concrete.t.u-tokyo.ac.jp; Chijiwa, Nobuhiro; Ishida, Tetsuya

2011-12-15T23:59:59.000Z

82

Topology-adaptive interface tracking using the deformable simplicial complex  

Science Conference Proceedings (OSTI)

We present a novel, topology-adaptive method for deformable interface tracking, called the Deformable Simplicial Complex (DSC). In the DSC method, the interface is represented explicitly as a piecewise linear curve (in 2D) or surface (in 3D) which ... Keywords: Deformable models, surface tracking, tetrahedral meshes

Marek Krzysztof Misztal; Jakob Andreas BŠrentzen

2012-05-01T23:59:59.000Z

83

Mining Deformation Features of Complex Engineering Slope via Safety Monitoring  

Science Conference Proceedings (OSTI)

A nonlinear regression model is presented in this article for mining deformation features of complex engineering slope on the basis of various monitoring data. It is aimed to discover the factors which have evident effect on slope deformation, as well ... Keywords: high steep slope, deformation mining, nonlinear regression, secular distortion, Jinping 1 hydropower station

Linwei Wang; Zaobao Liu; Dan Jin; Qingxiang Meng

2012-05-01T23:59:59.000Z

84

A fully coupled finite element model of coal deformation and two phase flow for coalbed methane extraction.  

E-Print Network (OSTI)

??A reservoir simulation model is usually required to represent the combined effects of gas transport, water flow, and coal swelling/shrinking on the extraction of coalbedů (more)

Chen, Dong

2012-01-01T23:59:59.000Z

85

Dual-channel Haptic Synthesis of Viscoelastic Tissue Properties using Programmable Eddy Current Brakes  

Science Conference Proceedings (OSTI)

We describe a novel method for haptic synthesis of viscoelastic responses which employs a dual-channel haptic interface. It has motors that generate torque independently of velocity and brakes that generate viscous torque independently of position. ... Keywords: eddy current brakes, haptic simulation, viscoelastic simulation

Andrew H. C. Gosline; Vincent Hayward

2009-10-01T23:59:59.000Z

86

Artificial neural network modeling to evaluate and predict the deformation behavior of stainless steel type AISI 304L during hot torsion  

Science Conference Proceedings (OSTI)

The deformation behavior of type 304L stainless steel during hot torsion is investigated using artificial neural network (ANN). Torsion tests in the temperature range of 600-1200^oC and in the (maximum surface) strain rate range of 0.1-100s^-^1 were ... Keywords: Artificial neural network, Austenitic stainless steel, Back propagation, Deformation behavior, Hot torsion, Resilient propagation, Sensitivity

Sumantra Mandal; P. V. Sivaprasad; S. Venugopal; K. P. N. Murthy

2009-01-01T23:59:59.000Z

87

Programmable shaders for deformation rendering  

Science Conference Proceedings (OSTI)

In this paper, we present a method for rendering deformations as part of the programmable shader pipeline of contemporary Graphical Processing Units. In our method, we allow general deformations including cuts. Previous approaches to deformation place ...

Carlos D. Correa; Deborah Silver

2007-08-01T23:59:59.000Z

88

Integral Kramers formula for the fission rate versus dynamical modeling: The case of deformation-dependent temperature  

Science Conference Proceedings (OSTI)

We have derived approximate analytical formulas describing the quasistationary fission rate of excited nuclei (the Kramers rates). These rates are compared with those resulting from dynamical modeling using the Smoluchowski equation (the dynamical rates). Contrary to the original Kramers approach, we have accounted for the microcanonical nature of the fission process. The influence of the potential at the scission point on the fission rates is also studied. Comparison with the dynamical rates enables us to define the accuracy of the Kramers rates in the wide range of the ratio of the fission barrier height B{sub f} to the temperature at the quasistationary state T{sub c} up to 16. These high values are not reachable within the traditional Langevin approach.

Gontchar, I. I.; Kuzyakin, R. A. [Physics and Chemistry Department, Omsk State Transport University, Omsk 644046 (Russian Federation)

2011-07-15T23:59:59.000Z

89

Physical Aging Effects of the Compressive Linear Viscoelastic Creep of IM7/K3B Composite  

Science Conference Proceedings (OSTI)

An experimental study was undertaken to establish the viscoelastic behavior of IM7/K3B composite in compression at elevated temperature. Creep compliance, strain recovery and the effects of physical aging on the time dependent response was measured for ...

Veazie D. R.; Gates T. S.

1995-12-01T23:59:59.000Z

90

Dynamics of bead formation, filament thinning and breakup in weakly viscoelastic jets  

E-Print Network (OSTI)

The spatiotemporal evolution of a viscoelastic jet depends on the relative magnitude of capillary, viscous, inertial and elastic stresses. The interplay of capillary and elastic stresses leads to the formation of very thin ...

Ardekani, Arezoo

91

Deformation - Observations and Modeling I  

Science Conference Proceedings (OSTI)

Oct 9, 2012 ... Sponsored by: TMS: Advanced Characterization, Testing, and Simulation ... tomography experiments were conducted at APS beamline 1-ID, ... We present results from a recent experiment at the Advanced Photon Source atá...

92

Atomistic Modeling on Deformation Mechanisms  

Science Conference Proceedings (OSTI)

Mar 12, 2012... Microstructure in Compression of Nanoscale Metallic Pillars by Molecular Dynamics Simulation: Frederic Sansoz1; 1University of Vermont

93

Deformation - Observations and Modeling II  

Science Conference Proceedings (OSTI)

Oct 9, 2012 ... Cold rolled grain oriented (CRGO) transformer steel was subjected to ... the spatial distribution of texture gradients within friction stir weldments.

94

Bulk Metallic Glasses Deform via Slip Avalanches  

E-Print Network (OSTI)

Inelastic deformation of metallic glasses occurs via slip events with avalanche dynamics similar to those of earthquakes. For the first time in these materials, measurements have been obtained with sufficiently high temporal resolution to extract both the exponents and the scaling functions that describe the nature, statistics and dynamics of the slips according to a simple mean-field model. These slips originate from localized deformation in shear bands. The mean-field model describes the slip process as an avalanche of rearrangements of atoms in shear transformation zones (STZs). Small slips show the predicted power-law scaling and correspond to limited propagation of a shear front, while large slips are associated with uniform shear on unconstrained shear bands. The agreement between the model and data across multiple independent measures of slip statistics and dynamics provides compelling evidence for slip avalanches of STZs as the elementary mechanism of inhomogeneous deformation in metallic glasses.

James Antonaglia; Wendelin J. Wright; Xiaojun Gu; Rachel R. Byer; Todd C. Hufnagel; Michael LeBlanc; Jonathan T. Uhl; Karin A. Dahmen

2013-12-21T23:59:59.000Z

95

Modelling creep deformation in floating ice1 K. van Steenis, F.E. Hicks, T.M Hrudey, and S. Beltaos  

E-Print Network (OSTI)

, and the construction of river structures (e.g., bridges) can also be performed from an ice platform. Another common use is a crystalline material that derives its strength from the intermolecular bonds within a hexagonal crystal, these imperfections can propagate through the crystal lattice, creating permanent deformation within the ice cover

Hicks, Faye E.

96

Electrically Deformable Liquid Marbles  

E-Print Network (OSTI)

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.

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

2011-02-17T23:59:59.000Z

97

The roles of deformation and orientation in heavy-ion collisions induced by light deformed nuclei at intermediate energy  

E-Print Network (OSTI)

The reaction dynamics of axisymmetric deformed $^{24}$Mg + $^{24}$Mg collisions have been investigated systematically by an isospin-dependent quantum molecular dynamics (IDQMD) model. It is found that different deformations and orientations result in apparently different properties of reaction dynamics. We revealed that some observables such as nuclear stopping power ($R$), multiplicity of fragments, and elliptic flow are very sensitive to the initial deformations and orientations. There exists an eccentricity scaling of elliptic flow in central body-body collisions with different deformations. In addition, the tip-tip and body-body configurations turn out to be two extreme cases in central reaction dynamical process.

X. G. Cao; G. Q. Zhang; X. Z. Cai; Y. G. Ma; W. Guo; J. G. Chen; W. D. Tian; D. Q. Fang; H. W. Wang

2010-05-26T23:59:59.000Z

98

Finding Deformable Shapes Using Loopy Belief Propagation  

Science Conference Proceedings (OSTI)

A novel deformable template is presented which detects and localizes shapes in grayscale images. The template is formulated as a Bayesian graphical model of a two-dimensional shape contour, and it is matched to the image using a variant of the belief ...

James M. Coughlan; Sabino J. Ferreira

2002-05-01T23:59:59.000Z

99

kappa-Deformed Oscillators: Deformed Multiplication Versus Deformed Flip Operator and Multiparticle Clusters  

E-Print Network (OSTI)

We transform the oscillator algebra with kappa-deformed multiplication rule, proposed in [1],[2], into the oscillator algebra with kappa-deformed flip operator and standard multiplication. We recall that the kappa-multiplication of the kappa-oscillators puts them off-shell. We study the explicit forms of modified mass-shell conditions in both formulations: with kappa-multiplication and with kappa-flip operation. On the example of kappa-deformed 2-particle states we study the clustered nonfactorizable form of the kappa-deformed multiparticle states. We argue that the kappa-deformed star product of two free fields leads in similar way to a nonfactorizable kappa-deformed bilocal field. We conclude with general remarks concerning the kappa-deformed n-particle clusters and kappa-deformed star product of n fields.

Jerzy Lukierski

2008-12-02T23:59:59.000Z

100

Shape Determination for Deformed Electromagnetic Cavities  

SciTech Connect

The measured physical parameters of a superconducting cavity differ from those of the designed ideal cavity. This is due to shape deviations caused by both loose machine tolerances during fabrication and by the tuning process for the accelerating mode. We present a shape determination algorithm to solve for the unknown deviations from the ideal cavity using experimentally measured cavity data. The objective is to match the results of the deformed cavity model to experimental data through least-squares minimization. The inversion variables are unknown shape deformation parameters that describe perturbations of the ideal cavity. The constraint is the Maxwell eigenvalue problem. We solve the nonlinear optimization problem using a line-search based reduced space Gauss-Newton method where we compute shape sensitivities with a discrete adjoint approach. We present two shape determination examples, one from synthetic and the other from experimental data. The results demonstrate that the proposed algorithm is very effective in determining the deformed cavity shape.

Akcelik, Volkan; Ko, Kwok; Lee, Lie-Quan; Li, Zhenghai; Ng, Cho-Kuen; Xiao, Liling; /SLAC

2007-12-10T23:59:59.000Z

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


101

Dynamic deformation of advanced materials  

SciTech Connect

This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to provide high-quality experimental measurements on composite materials and to develop computational models describing the deformation response of these materials. Specifically, the authors studied the influence of strain rate and shock loading on the deformation and fracture response of a 6061-T6 Al-50 vol.% Al{sub 2}O{sub 3} continuous fiber-reinforced composite as a function of composite orientation. The stress-strain response was found to vary substantially as a function of loading orientation with the quasi-static yield changing from nominally 300 MPa transverse to the fibers to {approximately}1,000 MPa parallel to the fibers. Transverse VISAR wave profile and spall measurements revealed a small, well-defined elastic precursor followed by a reasonably sharp shock rise. The failure response of the composite transverse to the fibers, under both uniaxial stress (quasi-static and dynamic) and uniaxial strain loading, displays a protracted but substantial load drop after yield followed by continued degradation in load carrying capacity. Lack of ideal parallel fiber construction leads to systematic bending failure of the alumina fibers through the sample under uniaxial stress and slow spallation kinetics as various fibers fail and pull out of the matrix across the spall plane.

Gray, G.T. III; Johnson, J.N.; Hixson, R.S.; Albert, D.E.; Song, S.

1996-04-01T23:59:59.000Z

102

Loop-deformed PoincarÚ algebra  

E-Print Network (OSTI)

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.

Jakub Mielczarek

2013-04-08T23:59:59.000Z

103

Finite element implementation of nearly-incompressible rheological models based on multiplicative decompositions  

Science Conference Proceedings (OSTI)

The present work is concerned with the numerical integration of finite viscoelastic or viscoplastic models. A numerical integration scheme based on the definition of a flow direction and a flow amplitude as in elastoplasticity is proposed. The most original ... Keywords: Finite elements, Finite strain, Integration scheme, Viscoelasticity, Viscoplasticity

S. Lejeunes; A. Boukamel; S. MÚo

2011-02-01T23:59:59.000Z

104

Modeling quasi-static poroelastic propagation using an asymptotic approach  

E-Print Network (OSTI)

model for multiphase ?ow through deformable fractured porousmultiphase ?uid ?ow, heat transfer, and deformation in fractured porous

Vasco, D.W.

2008-01-01T23:59:59.000Z

105

Deformations of topological open strings  

E-Print Network (OSTI)

Deformations of topological open string theories are described, with an emphasis on their algebraic structure. They are encoded in the mixed bulk-boundary correlators. They constitute the Hochschild complex of the open string algebra ľ the complex of multilinear maps on the boundary Hilbert space. This complex is known to have the structure of a Gerstenhaber algebra (Deligne theorem), which is also found in closed string theory. Generalising the case of function algebras with a B-field, we identify the algebraic operations of the bulk sector, in terms of the mixed correlators. This gives a physical realisation of the Deligne theorem. We translate to the language of certain operads (spaces of d-discs with gluing) and d-algebras, and comment on generalisations, notably to the AdS/CFT correspondence. The formalism is applied to the topological A-and B-models on the disc

Christiaan Hofman; Whee Ky Ma

2000-01-01T23:59:59.000Z

106

Role of BCS-type pairing in light deformed nuclei: A relativistic mean field approach  

E-Print Network (OSTI)

We calculate the binding energy and deformation parameter for light nuclei with and without pairing using a deformed relativistic mean field model. The role of BCS-type pairing effect is analyzed for Ne and F isotopes. The calculated odd-even staggering and the deformation parameters argue strongly against the role of pairing in the light nuclei.

P. Arumugam; T. K. Jha; S. K. Patra

2003-11-25T23:59:59.000Z

107

Effect of nuclear deformation on direct capture reactions  

E-Print Network (OSTI)

The direct radiative capture process is well described by the spherical potential model. In order for the model to explain direct captures more accurately, the effect of the nuclear deformation has been added and analyzed in this work, since most nucleuses are not spherical. The results imply that the nuclear deformation largely affects the direct capture and should be taken into account during discussing direct capture reactions.

G. W. Fan; X. L. Cai; M. Fukuda; Zhongzhou Ren; W. Xu

2013-05-01T23:59:59.000Z

108

Shape Determination for Deformed Cavities  

SciTech Connect

A realistic superconducting RF cavity has its shape deformed comparing to its designed shape due to the loose tolerance in the fabrication process and the frequency tuning for its accelerating mode. A PDE-constrained optimization problem is proposed to determine the deformation of the cavity. A reduce space method is used to solve the PDE-constrained optimization problem where design sensitivities were computed using a continuous adjoint approach. A proof-of-concept example is given in which the deformation parameters of a single cavity-cell with two different types of deformation were computed.

Lee, Lie-Quan; Akcelik, Volkan; Chen, Sheng; Ge, Lixin; Li, Zenghai; Ng, Cho; Xiao, Liling; Ko, Kwok; /SLAC; Ghattas, Omar; /Texas U.

2006-10-04T23:59:59.000Z

109

String deformations induced by retardation effects  

E-Print Network (OSTI)

The rotating string model is an effective model of mesons, in which the quark and the antiquark are linked by a straight string. We previously developed a new framework to include the retardation effects in the rotating string model, but the string was still kept straight. We now go a step further and show that the retardation effects cause a small deviation of the string from the straight line. We first give general arguments constraining the string shape. Then, we find analytical and numerical solutions for the string deformation induced by retardation effects. We finally discuss the influence of the curved string on the energy spectrum of the model.

F. Buisseret; V. Mathieu; C. Semay

2006-05-30T23:59:59.000Z

110

Variational Approach for Predicting the Load Deformation Response of a Double Stretched Membrane Reflector Module  

DOE Green Energy (OSTI)

This report presents an analytical model useful for design and sizing purposes to describe the load deformation response of a stretched membrane reflector module structural system.

Murphy, L. M.

1985-10-01T23:59:59.000Z

111

Nonmonotonic Relaxation as a Result of Spatial Heterogeneity in the Model of In-series Blocks Chain  

E-Print Network (OSTI)

Recently the materials possessing structure of molecular and supramolecular matrix are more and more actively studied. They are relative to many polymeric materials of a technological origin, such as rubber, and living biological tissues. Processes of mechanical deformation of these continuous media have peculiarities connected, first, with accounting for internal friction and dissipation of energy, and secondly, with nonlinearity of their elastic and viscous properties, that is with violation of Hook and Newtons laws. Traditional approaches to mechanics of viscoelastic bodies sometimes are excessively difficult, and more evident and available representations are necessary. The invaluable role in studying of the operating processes mechanisms of elastic deformation and motility of biological materials is played by the mathematical modeling. New effect obtained by means of computer experiment of nonmonotonic relaxation of deformation in heterogeneous media is considered in the present work. Rheological properties of described media are governed by the differential equations of the first order on time (the evolution equations), as well as a huge variety of other physical processes. The physical phenomena in nonlinear systems with dissipation have a big community, including such it would seem far areas, as dynamics of magnetization in ferrite. Therefore the problem of studying new effects of viscous friction in the conditions of nonlinearity and heterogeneity, is very actual as in respect of fundamental research nonlinear and non-uniform environments, and in many areas of materials science, design of new materials, engineering of biological substitutes of living tissues and development of the micromagnetic devices using essentially new opportunities.

A. A. Bedulina; A. V. Kobelev

2013-06-25T23:59:59.000Z

112

Variable focal length deformable mirror  

DOE Patents (OSTI)

A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.

Headley, Daniel (Albuquerque, NM); Ramsey, Marc (Albuquerque, NM); Schwarz, Jens (Albuquerque, NM)

2007-06-12T23:59:59.000Z

113

Anatomy-based modeling of the human musculature  

Science Conference Proceedings (OSTI)

Keywords: articulated models, bones, deformations, human figure animation, muscles, procedural modeling, tendons

Ferdi Scheepers; Richard E. Parent; Wayne E. Carlson; Stephen F. May

1997-08-01T23:59:59.000Z

114

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

E-Print Network (OSTI)

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.

Arutyunov, Gleb; Frolov, Sergey

2013-01-01T23:59:59.000Z

115

A viscoelastic representation of wave attenuation in porous media  

Science Conference Proceedings (OSTI)

The theories developed by White and co-workers describe the complex moduli of a medium partially saturated with spherical gas pockets and those of stratified layers composed of two heterogeneous porous media. A generalization to gas patches of arbitrary ... Keywords: Mesoscopic loss, Porous media, Wave attenuation, Zener model

Stefano Picotti; JosÚ M. Carcione; J. Germßn Rubino; Juan E. Santos; Fabio Cavallini

2010-01-01T23:59:59.000Z

116

Elastic encapsulation in bicomponent stratified flow of viscoelastic fluids  

E-Print Network (OSTI)

, Midland, Michigan 48667 James J. Fenga) Department of Chemical and Biological Engineering and Department. The simulations are based on a phase-field theoretical model and use finite elements with adaptive meshing the transport of highly viscous heavy crude oil in pipelines, where the addition of a small amount of water

Feng, James J.

117

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

SciTech Connect

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.

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

118

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

E-Print Network (OSTI)

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

Palmer, Jeffrey Shane

2008-01-01T23:59:59.000Z

119

Brownian motion in granular gases of viscoelastic particles  

Science Conference Proceedings (OSTI)

A theory is developed of Brownian motion in granular gases (systems of many macroscopic particles undergoing inelastic collisions), where the energy loss in inelastic collisions is determined by a restitution coefficient {epsilon}. Whereas previous studies used a simplified model with {epsilon} = const, the present analysis takes into account the dependence of the restitution coefficient on relative impact velocity. The granular temperature and the Brownian diffusion coefficient are calculated for a granular gas in the homogeneous cooling state and a gas driven by a thermostat force, and their variation with grain mass and size and the restitution coefficient is analyzed. Both equipartition principle and fluctuation-dissipation relations are found to break down. One manifestation of this behavior is a new phenomenon of 'relative heating' of Brownian particles at the expense of cooling of the ambient granular gas.

Bodrova, A. S., E-mail: bodrova@polly.phys.msu.ru; Brilliantov, N. V.; Loskutov, A. Yu. [Moscow State University (Russian Federation)

2009-12-15T23:59:59.000Z

120

Atomic Scale Deformation Mechanisms of Amorphous Polyethylene ...  

Science Conference Proceedings (OSTI)

Atomic Scale Deformation Mechanisms of Amorphous Polyethylene under Tensile Loading Ě Atomistic Predictions of Age Hardening in Al-Cu Alloys.

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


121

CubeSat deformable mirror demonstration  

E-Print Network (OSTI)

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 ...

Cahoy, Kerri

122

Mesh deformations in X3D via CUDA with freeform deformation lattices  

Science Conference Proceedings (OSTI)

In this paper we present a GPU-accelerated implementation of the well-known freeform deformation algorithm to allow for deformable objects within fully interactive virtual environments. We furthermore outline how our real-time deformation approach can ... Keywords: CUDA, FFD, X3D, deformable objects, real-time simulation

Yvonne Jung; Holger Graf; Johannes Behr; Arjan Kuijper

2011-07-01T23:59:59.000Z

123

Schmid et al. Inclusion Behavior in Deforming Rocks Inclusion Behavior in Deforming Rocks  

E-Print Network (OSTI)

Schmid et al. Inclusion Behavior in Deforming Rocks Inclusion Behavior in Deforming Rocks Dani Podladchikov, PGP, University of Oslo, Norway Intro 1 #12;Schmid et al. Inclusion Behavior in Deforming Rocks Motivation 2 The single most useful thing to understand! #12;Schmid et al. Inclusion Behavior in Deforming

Cesare, Bernardo

124

Phase-field Modeling of Deformation Twinning  

Science Conference Proceedings (OSTI)

... of Intrinsic Localized Modes Observed in the Vibrational Spectrum Of NaI ... Phonon Studies with Inelastic Neutron Scattering and First-Principles Simulations ... Reaction Pathways of Methane Decomposition on Cu Surface from Ab Initioá...

125

Physical and Statistical Models in Deformation Geodesy  

E-Print Network (OSTI)

2008), Mississippi Delta subsidence primarily caused bySultan (2009), Land subsidence in the nile delta: inferences2006), Space geodesy: Subsidence and ?ooding in New Orleans,

Lipovsky, Brad

2011-01-01T23:59:59.000Z

126

Atomistic Modeling and Characterization of Deformed Microstructures  

Science Conference Proceedings (OSTI)

Molybdenum disulphide (MoS2) has a layered, hexagonal crystal structure and is commonly used as a solid lubricant and liquid lubricant additive. The objectiveá...

127

Deformation study of separator pellets for thermal batteries  

DOE Green Energy (OSTI)

The deformation characteristics of pellets of electrolyte-binder (EB) mixes based on MgO were measured under simulated, thermal-battery conditions. Measurements (using a statistically designed experimental strategy) were made as a function of applied pressure, temperature, and percentage of theoretical density for four molten-salt electrolytes at two levels of MgO. The EB mixes are used as separators in Li-alloy thermal batteries. The electrolytes included LiCl-KCI eutectic, LiCl-LiBr-KBr eutectic, LiBr-KBr-LiF eutectic, and a LiCl-LiBr-LiF electrolyte with a minimum-melting composition. The melting points ranged from 313 C to 436 C. The experimental data were used to develop statistical models that approximate the deformation behavior of pellets of the various EB mixes over the range of experimental conditions we examined. This report, discusses the importance of the deformation response surfaces to thermal-battery design.

Guidotti, R.A.; Reinhardt, F.W.; Thomas, E.V.

1995-05-01T23:59:59.000Z

128

Discrete Breathers in Deformed Graphene  

E-Print Network (OSTI)

The linear and nonlinear dynamics of elastically deformed graphene have been studied. The region of the stability of a planar graphene sheet has been represented in the space of the two-dimensional strain (? xx, ? yy) with the x and y axes oriented in the zigzag and armchair directions, respectively. It has been shown that the gap in the phonon spectrum appears in graphene under uniaxial deformation in the zigzag or armchair direction, while the gap is not formed under a hydrostatic load. It has been found that graphene deformed uniaxially in the zigzag direction supports the existence of spatially localized nonlinear modes in the form of discrete breathers, the frequency of which decreases with an increase in the amplitude. This indicates soft nonlinearity in the system. It is unusual that discrete breather has frequency within the phonon spectrum of graphene. This is explained by the fact that the oscillation of the discrete breather is polarized in the plane of the graphene sheet, while the phonon spectral band where the discrete breather frequency is located contains phonons oscillating out of plane. The stability of the discrete breather with respect to the small out-of-plane perturbation of the graphene sheet has been demonstrated. DOI: 10.1134/S0021364011190106 1.

unknown authors

2011-01-01T23:59:59.000Z

129

A framework for coupling flow and deformation of the porous solid  

E-Print Network (OSTI)

In this paper, we consider the flow of an incompressible fluid in a deformable porous solid. We present a mathematical model using the framework offered by the theory of interacting continua. In its most general form, this framework provides a mechanism for capturing multiphase flow, deformation, chemical reactions and thermal processes, as well as interactions between the various physics in a conveniently implemented fashion. To simplify the presentation of the framework, results are presented for a particular model than can be seen as an extension of Darcy's equation (which assumes that the porous solid is rigid) that takes into account elastic deformation of the porous solid. The model also considers the effect of deformation on porosity. We show that using this model one can recover identical results as in the framework proposed by Biot and Terzaghi. Some salient features of the framework are as follows: (a) It is a consistent mixture theory model, and adheres to the laws and principles of continuum therm...

Turner, D Z; Martinez, M J

2013-01-01T23:59:59.000Z

130

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

SciTech Connect

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.

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

2010-09-01T23:59:59.000Z

131

Dynamics of a deformable active particle under shear flow  

E-Print Network (OSTI)

The motion of a deformable active particle in linear shear flow is explored theoretically. Based on symmetry considerations, in two spatial dimensions, we propose coupled nonlinear dynamical equations for the particle position, velocity, deformation, and rotation. In our model, both, passive rotations induced by the shear flow as well as active spinning motions, are taken into account. Our equations reduce to known models in the two limits of vanishing shear flow and vanishing particle deformability. For varied shear rate and particle propulsion speed, we solve the equations numerically and obtain a manifold of different dynamical modes including active straight motion, periodic motions, motions on undulated cycloids, winding motions, as well as quasi-periodic and chaotic motions induced at high shear rates. The types of motion are distinguished by different characteristics in the real-space trajectories and in the dynamical behavior of the particle orientation and its deformation. Our predictions can be verified in experiments on self-propelled droplets exposed to a linear shear flow.

Mitsusuke Tarama; Andreas M. Menzel; Borge ten Hagen; Raphael Wittkowski; Takao Ohta; Hartmut L÷wen

2013-07-08T23:59:59.000Z

132

Microstructure and Dynamic Deformation Behavior of Nanometer ...  

Science Conference Proceedings (OSTI)

Dynamic deformation behavior at strain rates of around 103 s-1 was performed using split Hopkinson bar technique. The results show that, the flow stressá...

133

Deformed Geometric Algebra and Supersymmetric Quantum Mechanics  

E-Print Network (OSTI)

Deforming the algebraic structure of geometric algebra on the phase space with a Moyal product leads naturally to supersymmetric quantum mechanics in the star product formalism.

Peter Henselder

2006-09-09T23:59:59.000Z

134

Deformation and Transitions at Grain Boundaries  

Science Conference Proceedings (OSTI)

Formation of cell-wall structure during deformation Ľ Intragranular boundaries: GNBs, IDBs, cell-block boundaries, etc. ... Hot Spots and Grain Boundaries.

135

Hydrogen Evolution Behaviour during Tensile Deformation in ...  

Science Conference Proceedings (OSTI)

Hydrogen evolution behaviour during tensile deformation and fracture was also investigated by using a testing machine equipped with a quadrupole massá...

136

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

SciTech Connect

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.

Kelemen, Peter

2012-08-24T23:59:59.000Z

137

Significant role of deformation in probing postsaddle nuclear dissipation with light particle emission  

Science Conference Proceedings (OSTI)

Using a one-dimensional Langevin model, we study the effects of deformation on the multiplicities of postsaddle neutrons, protons, alpha particles, and giant dipole resonance (GDR) gamma rays of a heavy fissioning system {sup 240}Cf as probes of postsaddle nuclear dissipation (beta). It is shown that postsaddle dissipation effects on these light particles have a significant deformation dependence. Furthermore, we find that the role of deformation depends on the type of the particle. It reduces the sensitive influence of beta on protons, alpha particles, and GDR gamma rays substantially, whereas it enhances the sensitivity of neutrons to beta. The results suggest that to accurately extract the postsaddle friction strength by comparing measured prescission particle multiplicities of heavy nuclei with calculations based on statistical models or stochastic equations like Langevin equations, it is important to take into account the deformation effects. The influence of model dimensionality is discussed.

Ye, W. [Department of Physics, Southeast University, Nanjing 210096, Jiangsu Province (China)

2010-05-15T23:59:59.000Z

138

Deformation and seismicity in the Coso geothermal area, Inyo County,  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon ┬╗ Deformation and seismicity in the Coso geothermal area, Inyo County, California, observations and modeling using satellite radar interferometry Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Deformation and seismicity in the Coso geothermal area, Inyo County, California, observations and modeling using satellite radar interferometry Details Activities (2) Areas (1) Regions (0) Abstract: Interferometric synthetic aperture radar (InSAR) data collected in the Coso geothermal area, eastern California, during 1993-1999 indicate ground subsidence over a approximately 50 km 2 region that approximately

139

Deformation of Olivine at Mantle Pressure using D-DIA  

Science Conference Proceedings (OSTI)

Knowledge of the rheological properties of mantle materials is critical in modeling the dynamics of the Earth. The high-temperature flow law of olivine defined at mantle conditions is especially important since the pressure dependence of rheology may affect our estimation of the strength of olivine in the Earth's interior. In this study, steady-state high-temperature (up to 1473 K) deformation experiments of polycrystalline olivine (average grain size ? 10 ?m) at pressure up to 9.6 GPa, were conducted using a Deformation-DIA (D-DIA) high-pressure apparatus and synchrotron X-ray radiation. The oxygen fugacity (fo2) during the runs was in-between the iron-wustite and the Ni/NiO buffers' fo2. The water content of the polycrystalline samples was generally about 150 to 200 wt. ppm but was as low as 35 wt ppm. Typically, 30 % strain was generated during the uniaxial compression. Sample lengths during the deformation process as well as the differential stresses were monitored in situ by X-ray radiography and diffraction, respectively. The strain rate was derived with an accuracy of 10?6 s?1. Differential stress was measured at constant strain rate (?10?5 s?1) using a multi-element solid-state detector combined with a conical slit. Recovered specimens were investigated by optical and transmission electron microscopy (TEM). TEM shows that dislocation glide was the dominant deformation mechanism throughout the experiment. Evidence of dislocation climb and cross-slip as active mechanisms are also reported. Deformation data show little or no dependence of the dislocation creep flow with pressure, yielding to an activation volume V* of 0 {+-} 5 cm3/mol. These new data are consistent with the high-temperature rheological laws at lower pressures, as reported previously.

Li,L.

2006-01-01T23:59:59.000Z

140

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

Science Conference Proceedings (OSTI)

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.

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

2012-01-01T23:59:59.000Z

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


141

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

SciTech Connect

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.

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

142

Deformation of Silica Aerogel During Fluid Adsorption  

E-Print Network (OSTI)

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.

Tobias Herman; James Day; John Beamish

2005-06-30T23:59:59.000Z

143

Multiscale framework for predicting the coupling between deformation and fluid diffusion in porous rocks  

SciTech Connect

In this project, a predictive multiscale framework will be developed to simulate the strong coupling between solid deformations and fluid diffusion in porous rocks. We intend to improve macroscale modeling by incorporating fundamental physical modeling at the microscale in a computationally efficient way. This is an essential step toward further developments in multiphysics modeling, linking hydraulic, thermal, chemical, and geomechanical processes. This research will focus on areas where severe deformations are observed, such as deformation bands, where classical phenomenology breaks down. Multiscale geometric complexities and key geomechanical and hydraulic attributes of deformation bands (e.g., grain sliding and crushing, and pore collapse, causing interstitial fluid expulsion under saturated conditions), can significantly affect the constitutive response of the skeleton and the intrinsic permeability. Discrete mechanics (DEM) and the lattice Boltzmann method (LBM) will be used to probe the microstructure---under the current state---to extract the evolution of macroscopic constitutive parameters and the permeability tensor. These evolving macroscopic constitutive parameters are then directly used in continuum scale predictions using the finite element method (FEM) accounting for the coupled solid deformation and fluid diffusion. A particularly valuable aspect of this research is the thorough quantitative verification and validation program at different scales. The multiscale homogenization framework will be validated using X-ray computed tomography and 3D digital image correlation in situ at the Advanced Photon Source in Argonne National Laboratories. Also, the hierarchical computations at the specimen level will be validated using the aforementioned techniques in samples of sandstone undergoing deformation bands.

Jos├ƒ ┬ę E. Andrade; John W. Rudnicki

2012-12-14T23:59:59.000Z

144

A q-deformed nonlinear map  

E-Print Network (OSTI)

A scheme of q-deformation of nonlinear maps is introduced. As a specific example, a q-deformation procedure related to the Tsallis q-exponential function is applied to the logistic map. Compared to the canonical logistic map, the resulting family of q-logistic maps is shown to have a wider spectrum of interesting behaviours, including the co-existence of attractors -- a phenomenon rare in one dimensional maps.

Ramaswamy Jaganathan; Sudeshna Sinha

2004-08-19T23:59:59.000Z

145

'Spin Casting' And 'Cold Deformation'  

Science Conference Proceedings (OSTI)

Numerical Modeling of Centrifugally Cast HSS Rolls Ě Numerical Simulation of Electro-magnetic Turbulent Inhibitor Technology in a Tundish Ě Optimizing theá...

146

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

SciTech Connect

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.

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

2012-06-07T23:59:59.000Z

147

High Temperature Anisotropic Deformation of SRR99 ModelLing ...  

Science Conference Proceedings (OSTI)

behaviour as well as of crystallographic and macroscopic geometrical changes in .... failure at 850░C. 550MPa with a total strain to failure of 5.8%. It is important to ... near Oil> ate not stable and in general rotate away from this orientation, asá...

148

Electric field Induced Patterns in Soft Visco-elastic films: From Long Waves of Viscous Liquids to Short Waves of Elastic Solids  

E-Print Network (OSTI)

We show that the electric field driven surface instability of visco-elastic films has two distinct regimes: (1) The visco-elastic films behaving like a liquid display long wavelengths governed by applied voltage and surface tension, independent of its elastic storage and viscous loss moduli, and (2) the films behaving like a solid require a threshold voltage for the instability whose wavelength always scales as ~ 4 x film thickness, independent of its surface tension, applied voltage, loss and storage moduli. Wavelength in a narrow transition zone between these regimes depends on the storage modulus.

N. Arun; Ashutosh Sharma; Partho S. G. Pattader; Indrani Banerjee; Hemant M. Dixit; K. S. Narayan

2009-06-02T23:59:59.000Z

149

Real-time haptic incision simulation using FEM-based discontinuous free form deformation  

Science Conference Proceedings (OSTI)

Computer-aided surgical simulation is a topic of increasingly extensive research. Computer graphics, geometric modeling and finite-element analysis all play major roles in these simulations. Furthermore, real-time response, interactivity and accuracy ... Keywords: finite element model, free-form deformation, surgical simulation

Guy Sela; Jacob Subag; Alex Lindblad; Dan Albocher; Sagi Schein; Gershon Elber

2006-06-01T23:59:59.000Z

150

The Effect Of Viscoelastic Surfactants Used In Carbonate Matrix Acidizing On Wettability  

E-Print Network (OSTI)

Carbonate reservoirs are heterogeneous; therefore, proper acid placement/diversion is required to make matrix acid treatments effective. Viscoelastic surfactants (VES) are used as diverting agents in carbonate matrix acidizing. However, these surfactants can adversely affect wettability around the wellbore area. Lab and field studies show that significant amounts of VES are retained in the reservoir, even after an EGMBE postflush. Optimizing acid treatments requires a study of the effect of VES on wettability. In a previous study using contact angle experiments, it was reported that spent acid solutions with VES only, and with VES and EGMBE are water-wetting. In this thesis, we studied the effect of two amphoteric amine-oxide VES', designated as "A" and "B" on the wettability of Austin cream chalk using contact angle experiments. We extended the previous study by using outcrop rocks prepared to simulate reservoir conditions, by demonstrating that VES adsorbs on the rock using two-phase titration experiments, by studying the effect of temperature on wettability and adsorption, and by developing a detailed procedure for contact angle experiments. We found that for initially oil-wet rocks, simulated acid treatments with VES "A" and "B" diversion stages and an EGMBE preflush and postflush made rocks water-wet at 25, 80, and 110 degrees C. Simulated acid treatments with a VES "A" diversion stage only made rocks water-wet at 25 degrees C. Our results suggest that both VES formulations cause a favorable wettability change for producing oil. The two-phase titration experiments show that both VES "A" and "B" adsorb on the rock surface. From our literature review, many surfactant wettability studies use contact angle measurements that represent advancing contact angles. However, wettability during stimulation is represented by receding contact angles. Results of static receding contact angles may be misinterpreted if low oil-acid IFT's cause oil droplets to spread. Spreading could be a reflection of the effect of the surfactants on the fluid-fluid interface rather than the rock-fluid interface. The new procedure shows the effect of VES and EGMBE on the rock-fluid interface only, and so represents the actual wettability.

Adejare, Oladapo

2012-05-01T23:59:59.000Z

151

Reciprocal transformations and deformations of integrable hierarchies  

E-Print Network (OSTI)

We present changes of variables that transform new integrable hierarchies found by Szablikowski and B{\\l}aszak using the $R$-matrix deformation technique [J. Math. Phys. 47 (2006), paper 043505, nlin.SI/0501044] into known Harry-Dym-type and mKdV-type hierarchies.

A. Sergyeyev

2008-12-30T23:59:59.000Z

152

Joining of advanced materials by superplastic deformation  

DOE Patents (OSTI)

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.

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

2008-08-19T23:59:59.000Z

153

Stochastic deformation of a thermodynamic symplectic structure  

E-Print Network (OSTI)

A stochastic deformation of a thermodynamic symplectic structure is studied. Gauge symmetries of thermodynamics and stochastic mechanics are revealed and gauge fields are introduced. A physical interpretation to the gauge transformations and gauge fields is given. An application of the formalism to a description of systems with distributed parameters in a local thermodynamic equilibrium is considered.

Kazinski, P O

2008-01-01T23:59:59.000Z

154

On a Model of Superconductivity and Biology  

E-Print Network (OSTI)

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.

Monica De Angelis

2012-03-02T23:59:59.000Z

155

Experimental deformation of natural and synthetic dolomite  

E-Print Network (OSTI)

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 dolomite deformed at low temperature (T ? 700??C for coarse-grained natural dolomite, T < 700??C for fine-grained natural and synthetic dolomite) exhibit mechanical behavior that is nearly plastic; differential stresses are insensitive to strain rate, fitted either by a power law no?????????=??????31&& with n values that range from 12 to 49 or an exponential law ([31exp )] ??????=o&& with exponential law term ? values from 0.023 to 0.079 MPa-1. Microstructures of samples deformed at low temperatures include mechanical twins, and undulatory extinction suggesting that twin glide and dislocation slip are the predominant deformation mechanisms. At high temperatures (T ? 800??C) flow strengths of coarse- and fine-grained dolomite depend more strongly on strain-rate and exhibit pronounced temperature dependencies. Microstructures of coarse-grained dolomite samples deformed at T ? 800??C include undulatory extinction and fine recrystallized grains suggesting that recovery and dynamic recrystallization contribute to dislocation creep at these conditions. By comparison with lower temperature deformation, mechanical twinning is unimportant. Fine-grained synthetic dolomite deformed at high temperature (T ? 700??C) exhibits nearly linear (Newtonian) viscous behavior, with n = 1.28 (??0.15) consistent with grain boundary (Coble) diffusion creep. At low temperatures (T ? 700??C) coarse-grained dolomite exhibits higher strengths at higher temperatures which cannot be described by an Arrhenius relation, while fine-grained dolomite strengths show little or no temperature dependence. At high temperatures (T ? 800??C), dislocation creep of coarse-grained dolomite can be described by a thermally activated power law ??????????????????=RTHno*31exp??????&& with H*/n = 60 kJ/mol, or by an exponential law ()[]??????????=RTHo*31expexp?????&& with H*/? = 25447 kJ/mol. At high temperatures, diffusion creep of fine-grained synthetic dolomite can be described by ?????????????????????????=RTHdno*313exp??????&& with H* = 280 ??45 kJ/mol. Taken together, the flow laws for coarse- and fine-grained dolomites constrain the high temperature conditions over which crystal plasticity, dislocation creep, and diffusion creep dominate.

Davis, Nathan Ernest

2005-08-01T23:59:59.000Z

156

Temporal diffeomorphic free form deformation (TDFFD) applied to motion and deformation quantification of tagged MRI sequences  

Science Conference Proceedings (OSTI)

This paper presents strain quantification results obtained from the Tagged Magnetic Resonance Imaging (TMRI) sequences acquired for the 1st cardiac Motion Analysis Challenge (cMAC). We applied the Temporal Diffeomorphic Free Form Deformation ...

Mathieu De Craene; Catalina Tobon-Gomez; Constantine Butakoff; Nicolas Duchateau; Gemma Piella; Kawal S. Rhode; Alejandro F. Frangi

2011-09-01T23:59:59.000Z

157

PBW-deformations and deformations Ó la Gerstenhaber of N-Koszul algebras.  

E-Print Network (OSTI)

In this article we establish an explicit link between the classical theory of deformations Ó la Gerstenhaber -- and a fortiori with the Hochschild cohomology-- and (weak) PBW-deformations of homogeneous algebras. Our point of view is of cohomological nature. As a consequence, we recover a theorem by R. Berger and V. Ginzburg, which gives a precise condition for a filtered algebra to satisfy the so-called PBW property, under certain assumptions.

Estanislao Herscovich; Andrea Solotar; Mariano Sußrez-┴lvarez

158

Novel Methods for Deformation Testing of Metals and Materials  

Science Conference Proceedings (OSTI)

About this Symposium. Meeting, Materials Science & Technology 2012. Symposium, Novel Methods for Deformation Testing of Metals and Materials.

159

Towards Understanding the Deformation and Fracture Behavior of ...  

Science Conference Proceedings (OSTI)

Presentation Title, Towards Understanding the Deformation and Fracture Behavior of Gas Turbine Structural Materials at Elevated Temperatures. Author(s) á...

160

Dynamic deformation behavior of equal channel angular extruded ...  

Science Conference Proceedings (OSTI)

X-ray diffraction and transmission electron microscope analyses was conducted to identify the possible deformation mechanisms. Proceedings Inclusion?

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161

Microstructure-strength relationships of heavily deformed magnesium-lithium composites containing steel fibers  

SciTech Connect

The successful development of deformation-processed metal-metal composites (DMMC) offers the potential for ductile, high-strength structural materials with high-temperature stability. An infiltration casting process was used to permeate steel wool preforms with molten magnesium-lithium (Mg-Li) alloys. The selected matrix alloys were hexagonal close packed (HCP) Mg-4wt%Li or body centered cubic (BCC) Mg-12wt%Li; the low carbon steel wool fibers were predominantly BCC ferrite. These cast HCP/BCC and BCC/BCC composites were deformed by rolling or by extrusion and swaging. Mechanical properties, microstructure, and texture development of the composites were characterized at various levels of deformation. The HCP/BCC composites had limited formability at temperatures up to 400 C while the BCC/BCC composites had excellent formability during sheet rolling at room temperature but limited formability during swaging at room temperature. The tensile strengths of these HCP/BCC and BCC/BCC composite materials increased moderately with deformation, though less than predicted from rule of mixtures (ROM) calculations. The microstructure was characterized to correlate the filament size to the deformation strain and mechanical properties of the composite material. Stereological measurements of the filament size were used to adjust ROM calculations to reflect the actual deformation strain in the fibers. However, the experimental strengths of these composite materials were still less than ROM predictions, possibly due to the presence of considerably large fibers. Of the many models used to describe the strengthening observed in DMMC materials, the Hall-Petch relationship adequately described the experimental data. Texture development was also characterized to explain the deformation characteristics of the composite materials. Chapters 2, 3 and 4 are not included here. They are being processed separately.

Jensen, J.

1997-10-08T23:59:59.000Z

162

Deformation and fracturing using adaptive shape matching with stiffness adjustment  

Science Conference Proceedings (OSTI)

This paper presents a fast method that computes deformations with fracturing of an object using a hierarchical lattice. Our method allows numerically stable computation based on so-called shape matching. During the simulation, the deformed shape of the ... Keywords: fracturing, interactive deformation, shape matching, soft body

Makoto Ohta; Yoshihiro Kanamori; Tomoyuki Nishita

2009-06-01T23:59:59.000Z

163

The Conformal Window of deformed CFT's in the planar limit  

E-Print Network (OSTI)

We discuss in the planar approximation the effect of double-trace deformations on CFT's. We show that this large class of models posses a conformal window describing a non-trivial flow between two fixed points of the renormalization group, and reveal the presence of a resonance which we associate to the remnant of a dilaton pole. As the conformal window shrinks to zero measure the theory undergoes a conformal phase transition separating a symmetric from a nonsymmetric phase. The recently conjectured strongly coupled branch of non-supersymmetric, non-abelian gauge theories with a large number of flavors is analyzed in light of these results, and a model for the strong branch is proposed. Some phenomenological implications in the context of unparticle physics are also emphasized.

Luca Vecchi

2010-04-12T23:59:59.000Z

164

Shock wave absorber having a deformable liner  

DOE Patents (OSTI)

This invention discloses a shock wave absorber for a piping system carrying liquid. The absorber has a plastically deformable liner defining the normal flow boundary for an axial segment of the piping system, and a nondeformable housing is spaced outwardly from the liner so as to define a gas-tight space therebetween. The flow capacity of the liner generally corresponds to the flow capacity of the piping system line, but the liner has a noncircular cross section and extends axially of the piping system line a distance between one and twenty times the diameter thereof. Gas pressurizes the gas-tight space equal to the normal liquid pressure in the piping system. The liner has sufficient structural capacity to withstand between one and one-half and two times this normal liquid pressures; but at greater pressures it begins to plastically deform initially with respect to shape to a more circular cross section, and then with respect to material extension by circumferentially stretching the wall of the liner. A high energy shock wave passing through the liner thus plastically deforms the liner radially into the gas space and progressively also as needed in the axial direction of the shock wave to minimize transmission of the shock wave beyond the absorber.

Youngdahl, C.K.; Wiedermann, A.H.; Shin, Y.W.; Kot, C.A.; Ockert, C.E.

1983-08-26T23:59:59.000Z

165

On Coating Durability of Polymer Coated Sheet Metal under Plastic Deformation  

E-Print Network (OSTI)

Polymer coated sheet metal components find diverse applications in many industries. The manufacturing of the components generally involves forming of sheet metal into the desired shape and coating of the formed part with organic coating. An alternative manufacturing route is to coat the sheet metal first before forming. The change in the manufacturing sequence can potentially improve cost and reduce environmental impact. This approach, however, requires the coating to survive the deformation process. Thus, the effect of plastic deformation on coating adhesion is of primary interest to many engineers and researchers. This research aims at developing a methodology to predict the adhesion of coating after metal forming processes. A pull-off apparatus that measures the coating pull-off stress was used to indicate the coating adhesion strength. Several types of specimen were designed to obtain uniaxial tension, biaxial tension, and tension-compression deformation modes on pre-coated sheet by using a uniaxial tensile tester. Experimental results from two selected polymer coated sheet metals show that coating adhesion was affected by plastic deformation. An analytical model based on a virtual interface crack concept was developed to indicate the adhesion potential of the coating-substrate interface. From interfacial fracture mechanics, the initial adhesion potential is defined as the energy release rate characterized by the virtual interface crack and the initial pull-off stress. The analytical model was used to predict coating adhesion loss after deformation in uniaxial tension mode. The analytical model predictions agreed well with experimental results. Finite element analysis tool was applied to simulate more complex deformation modes in stamping of coated sheet meals. The stress field near the interface crack tip was used to calculate the energy release rate and predict the adhesion loss under different deformation modes. The predictions obtained from numerical method are also in good agreements with the experimental results in biaxial tension and tension-compression modes. The research has led to a better understanding of the effects of plastic deformation on coating adhesion. The developed adhesion test methods can be used to generate useful information on coating durability for diverse practical use. It is also expected that the results of the research will facilitate the development of better polymer coated sheet metal to be used in sheet metal forming processes.

Huang, Yu-Hsuan

2010-05-01T23:59:59.000Z

166

Comparison between the Morse eigenfunctions and deformed oscillator wavefunctions  

Science Conference Proceedings (OSTI)

In this work we introduce deformed creation and annihilation operators which differ from the usual harmonic oscillator operators a, a{sup {dagger}} by a number operator function A circumflex = a circumflex f(n circumflex ), A circumflex {sup {dagger}} = f(n circumflex )a circumflex {sup {dagger}}. We construct the deformed coordinate and momentum in terms of the deformed operators and maintain only up to first order terms in the deformed operators. By application of the deformed annihilation operator upon the vacuum state we get the ground state wavefunction in the configuration space and the wavefunctions for excited states are obtained by repeated application of the deformed creation operator. Finally, we compare the wavefunctions obtained with the deformed operators with the corresponding Morse eigenfunctions.

Recamier, J.; Mochan, W. L. [Instituto de Ciencias Fisicas Universidad Nacional Autonoma de Mexico Apdo. Postal 48-3, Cuernavaca, Mor., 62251 Mexico (Mexico); Gorayeb, M. [Instituto de Ciencias Fisicas Universidad Nacional Autonoma de Mexico Apdo. Postal 48-3, Cuernavaca, Mor., 62251 Mexico (Mexico); Departamento de Quimica, Universidad Simon Bolivar, Apartado 89000, Caracas 1080A (Venezuela); Paz, J. L. [Departamento de Quimica, Universidad Simon Bolivar, Apartado 89000, Caracas 1080A (Venezuela)

2008-04-15T23:59:59.000Z

167

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

Open Energy Info (EERE)

Steady state deformation of the Coso Range, east central California, Steady state deformation of the Coso Range, east central California, inferred from satellite radar interferometry Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Steady state deformation of the Coso Range, east central California, inferred from satellite radar interferometry Details Activities (2) Areas (1) Regions (0) Abstract: Observations of deformation from 1992 to 1997 in the southern Coso Range using satellite radar interferometry show deformation rates of up to 35 mm yr -1 in an area approximately 10 km by 15 km. The deformation is most likely the result of subsidence in an area around the Coso geothermal field. The deformation signal has a short-wavelength component, related to production in the field, and a long-wavelength component,

168

Plastic deformation of ordered intermetallic alloys: Fundamental aspects  

SciTech Connect

Fundamental aspects of plastic deformation in ordered intermetallic alloys are reviewed by directly comparing the temperature-dependent yield stresses of Ni{sub 3}Al and Ni{sub 3}Si (the L1{sub 2} structure), NiAl and FeAl (the B2 structure), and TiAl and Ti{sub 3}Al (non-cubic L1{sub 0} and D0{sub 19} structures, respectively). While the yield strength anomaly observed in Ni{sub 3}Al is consistent with the prevailing dislocation models, that found in stoichiometric Ni{sub 3}Si is not. The strong plastic anisotropy observed in NiAl stems from the high antiphase boundary energy, and that found in two-phase {gamma}-TiAl/{alpha}{sub 2}-Ti{sub 3}Al is due to the exceptionally high compressive yield strength along the c-axis of Ti{sub 3}Al.

Yoo, M.H. [Max-Planck-Inst. fuer Eisenforschung, Duesseldorf (Germany)

1994-10-01T23:59:59.000Z

169

Non-principal surface waves in deformed incompressible materials  

E-Print Network (OSTI)

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.

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

2013-04-23T23:59:59.000Z

170

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. XXX, XXXX, DOI:10.1029/2006JB004763, 2007 Persistent Scatterer InSAR for Crustal Deformation Analysis, with  

E-Print Network (OSTI)

of deformation. The first we model as a contracting pipe-like body, which we interpret to be a crystallizing known to have erupted rhyolite as well as basalt [Geist et al., 1994]. The last known eruption occurred

Segall, Paul

171

A Langevin equation description of dynamic nuclear deformation  

SciTech Connect

A model of dynamic nuclear deformation is developed in which the collective degrees of freedom of a nucleus are coupled to subcollective degrees of freedom by means of friction and fluctuation forces in the equations of motion for the collective degrees of freedom. The Langevin equation is a stochastic differential equation that includes friction and fluctuation terms, so it is used as the equation of motion in this model. The necessary inertia and friction parameters are obtained using the Werner-Wheeler approximation, and the fluctuation parameter is obtained by applying the fluctuation-dissipation theorem. It is shown that a second order Runge-Kutta method for numerical solution of the Langevin equation is much better than the commonly employed Euler method. Poor random number generators are shown to have serious negative effects in a Langevin simulation. Several case studies are described, including a model employing the (c, h, [alpha]) shape parameterization with h set equal to zero to reduce it to two dimensions. This parameterization allows scission into fragments of varying relative sizes, providing a suitable model for study for mass distributions, transient times, and the importance of dynamics on distributions and scission rates.

Roeth, N.L.

1992-01-01T23:59:59.000Z

172

Wilson loops in warped resolved deformed conifolds  

Science Conference Proceedings (OSTI)

We calculate quark-antiquark potentials using the relationship between the expectation value of the Wilson loop and the action of a probe string in the string dual. We review and categorise the possible forms of the dependence of the energy on the separation between the quarks. In particular, we examine the possibility of there being a minimum separation for probe strings which do not penetrate close to the origin of the bulk space, and derive a condition which determines whether this is the case. We then apply these considerations to the flavoured resolved deformed conifold background of Gaillard et al. (2010) . We suggest that the unusual behaviour that we observe in this solution is likely to be related to the IR singularity which is not present in the unflavoured case. - Highlights: > We calculate quark-antiquark potentials using the Wilson loop and the action of a probe string in the string dual. > We review and categorise the possible forms of the dependence of the energy on the separation between the quarks. > We look in particular at the flavoured resolved deformed conifold. > There appears to be unusual behaviour which seems likely to be related to the IR singularity introduced by flavours.

Bennett, Stephen, E-mail: pystephen@swansea.ac.uk

2011-11-15T23:59:59.000Z

173

Well-developed deformation in 42Si  

E-Print Network (OSTI)

Excited states in 38,40,42Si nuclei have been studied via in-beam gamma-ray spectroscopy with multi-nucleon removal reactions. Intense radioactive beams of 40S and 44S provided at the new facility of the RIKEN Radioactive Isotope Beam Factory enabled gamma-gamma coincidence measurements. A prominent gamma line observed with an energy of 742(8) keV in 42Si confirms the 2+ state reported in an earlier study. Among the gamma lines observed in coincidence with the 2+ -> 0+ transition, the most probable candidate for the transition from the yrast 4+ state was identified, leading to a 4+_1 energy of 2173(14) keV. The energy ratio of 2.93(5) between the 2+_1 and 4+_1 states indicates well-developed deformation in 42Si at N=28 and Z=14. Also for 38,40Si energy ratios with values of 2.09(5) and 2.56(5) were obtained. Together with the ratio for 42Si, the results show a rapid deformation development of Si isotopes from N=24 to N=28.

S. Takeuchi; M. Matsushita; N. Aoi; P. Doornenbal; K. Li; T. Motobayashi; H. Scheit; D. Steppenbeck; H. Wang; H. Baba; D. Bazin; L. CÓceres; H. Crawford; P. Fallon; R. Gernhńuser; J. Gibelin; S. Go; S. GrÚvy; C. Hinke; C. R. Hoffman; R. Hughes; E. Ideguchi; D. Jenkins; N. Kobayashi; Y. Kondo; R. KrŘcken; T. Le Bleis; J. Lee; G. Lee; A. Matta; S. Michimasa; T. Nakamura; S. Ota; M. Petri; T. Sako; H. Sakurai; S. Shimoura; K. Steiger; K. Takahashi; M. Takechi; Y. Togano; R. Winkler; K. Yoneda

2012-07-26T23:59:59.000Z

174

ROCK DEFORMATION 2010 GORDON RESEARCH CONFERENCE, AUGUST 8-13, 2010  

DOE Green Energy (OSTI)

Creep in the crust and mantle is commonly considered a steady-state process. This view prevails despite the fact that earthquakes do not represent steady-state and at the base of the seismogenic zone, for example, the stresses that drive creep must vary with the earthquake cycle. The contribution of transient versus steady-state behavior is not easy to determine from naturally-deformed brittle or plastic rocks and our view of steady-state depends on whether we consider geological or shorter time-scales. Perhaps we avoid a non steady-state picture because we lack appropriate descriptive or quantitative tools. The aim of the 2010 Gordon Research Conference (GRC) in rock deformation is to explore what we know about non steady-state deformation and how we might advance our understanding through geological and geophysical field investigations, laboratory experiments and modeling. This will require an appraisal of the applicability of steady-state concepts as well as an exploration of transient behavior, in which processes and physical properties cycle between different states as might be the case during earthquake cycles, and transitions in behavior, where finite strain or changing environmental conditions lead to changes in processes and properties. Conference sessions will cover seven broad and interlinked topics. (1) What is steady state?; an appraisal of applicability of the steady-state concept in rock deformation. (2) Seismogenic Faulting and Brittle Fault Rocks; where transience in rates and conditions are accepted but not fully understood. (3) Episodic Creep During the Seismic Cycle; with a focus on processes in areas adjacent to the base of the seismogenic zone. (4) Creep in Zones of Stress and Temperature Cycling; considering deformation in real-world complex systems (5) Deformation, Metamorphism, and Fluids; exploring the interaction of diagenesis/metamorphism and thermal instabilities with deformation. (6) Mechanism and Microstructure Transitions During Deformation; quantifying evolution as a function of strain and associated with changes in deformation kinematics or conditions. (7) Mechanism and Microstructure Transitions Related to Mantle Geophysics; with a focus on the link between mechanisms affecting processes on geological time-scales on the time-scales associated with seismic wave propagation. The GRC on Rock Deformation aims to bring together researchers with diverse expertise, and to shape the scientific debate and provide inspiration for young researchers to fill the still extensive gaps in our knowledge of how the Earth deforms. The processes that will be discussed have wide applications in both basic and applied research. A key issue, of fundamental importance to our understanding of the Earth, for discussion at this meeting will be the transition from time-dependent (and distributed) rock deformation, including both high temperature creep and brittle creep, to episodic (and more localized) events. Such transitions have both a scientific and a socio-economic impact since they control the precursory phases of important geohazards such as earthquake rupture and volcanic eruptions, and also influence effective recovery of hydrocarbon and geothermal energy resources, and the integrity of long-term storage facilities for hazardous waste.

David Prior

2010-08-13T23:59:59.000Z

175

Electric field-induced deformation of polyelectrolyte gels  

Science Conference Proceedings (OSTI)

Water-swollen polyelectrolyte gels deform in an electric field. We observed that the sign and magnitude of the deformation is dependent on the nature of the salt bath in which the gel is immersed and electrocuted. These results are compatible with a deformation mechanism based upon creation of ion density gradients by the field which, in turn, creates osmotic pressure gradients within the gel. A consistent interpretation results only if gel mobility is allowed as well as free ion diffusion and migration.

Adolf, D.; Hance, B.G.

1995-08-01T23:59:59.000Z

176

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

Open Energy Info (EERE)

Steady state deformation of the Coso Range, east central California, inferred from satellite radar interferometry Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home...

177

Local Deformation Tracking at the Microstructural Level in Coarse ...  

Science Conference Proceedings (OSTI)

Presentation Title, Local Deformation Tracking at the Microstructural Level in Coarse and Ultrafine-Grained Metals. Author(s), Adam Kammers, Samantha Daly

178

Education: Digital Resource Center - VISUALS: Deformation of Solids  

Science Conference Proceedings (OSTI)

Feb 12, 2007 ... This link provides a ball and stick animation of dislocation motion. Citation: "Part IB Course F: Deformation of Solids, Lecture 1." Department ofá...

179

Introduccion a la mecanica de los solidos deformables  

E-Print Network (OSTI)

Introducci┬┤on a la mec┬┤anica de los s┬┤olidos deformables Ignacio Romero Olleros E.T.S. Ingenieros

Romero, Ignacio

180

Surface Deformation from Satellite Data and Geothermal Assessment...  

Open Energy Info (EERE)

NA, 2012 DOI Not Provided Check for DOI availability: http:crossref.org Online Internet link for Surface Deformation from Satellite Data and Geothermal Assessment,...

Note: This page contains sample records for the topic "viscoelastic deformation model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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to obtain the most current and comprehensive results.


181

Geodetic Constraints on Contemporary Deformation in the Northern...  

Open Energy Info (EERE)

America, 2009 DOI Not Provided Check for DOI availability: http:crossref.org Online Internet link for Geodetic Constraints on Contemporary Deformation in the Northern Walker...

182

Influence of Reinforcement Homogeneity on the Deformation and ...  

Science Conference Proceedings (OSTI)

... to determine deformation and fracture behavior for each condition of homogeneity via compression tests and chevron-notch short rod specimens, respectively.

183

The Research on Controlling the Pre-Bending Deformation before ...  

Science Conference Proceedings (OSTI)

The straightness and residual stresses of the rail after straightening are affected by the bending deformation during cooling before straightening. By analyzingá...

184

Dynamical SUSY Breaking and the Beta-Deformation  

E-Print Network (OSTI)

We study supersymmetry breaking metastable vacua arising from beta deformed quiver gauge theories. The relation between the bounds on metastability and the deformation are discussed. Metastable supersymmetry breaking vacua are found in the IR of beta deformed cascading quivers with vector-like field content. Furthermore the limiting case of massive Nf=Nc SQCD appears in the IR of gauge theories with chiral-like field content. We comment on the field theory origin of the deformation and on possible applications in AdS/CFT.

Amariti, A

2010-01-01T23:59:59.000Z

185

Fatigue Deformation and Failure of Carbon Nanotube-loaded ...  

Science Conference Proceedings (OSTI)

Abstract Scope, The cyclic deformation of individual fibers has been studied in the textile ... Our room temperature experiments on plain and carbon nanotube-

186

Particle Size on the Deformation Mechanism in an Advanced ...  

Science Conference Proceedings (OSTI)

field emission gun scanning electron microscope (FEGSEM). Deformation ... with post mortem electron microscopy studies that the load transfer observed can beá...

187

Deformation Prediction of a Heavy Hydro Turbine Blade During ...  

Science Conference Proceedings (OSTI)

Presentation Title, Deformation Prediction of a Heavy Hydro Turbine Blade During ... Abstract Scope, Heavy hydro turbine castings are made of martensiticá...

188

Deformation debris and their contribution to hindering dislocations  

Science Conference Proceedings (OSTI)

Presentation Title, Deformation debris and their contribution to hindering dislocations -- atomistic simulations in aluminum. Author(s), Hao Wang, Dongsheng Xu,á...

189

Effect of Plastic Deformation on Sn Whisker Growth in Electroplated ...  

Science Conference Proceedings (OSTI)

Symposium, Pb-free Solders and Emerging Interconnect and Packaging Technologies. Presentation Title, Effect of Plastic Deformation on Sn Whisker Growth iná...

190

Materials' Deformation Dynamics at Atomic Scale In situ Atomic ...  

Science Conference Proceedings (OSTI)

Presentation Title, Materials' Deformation Dynamics at Atomic Scale In situ Atomic .... What Can We Learn from Measurements of Li-ion Battery Single Particles?

191

Tuning the Properties of Carbon Nanotubes by Deformation ...  

Science Conference Proceedings (OSTI)

... Back to Tuning the Properties of Carbon Nanotubes by Deformation. Last modified 31-May-2002 by website owner: NCNR (attn: Bill Kamitakahara).

192

Deformation Behavior of Steel Alloys under Combined Axial ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Using hollow cylinder samples with suitable geometry obtained from round bar stock and flat dog-bone samples from sheets, the deformationá...

193

Free motion in deformed (quantum) four-dimensional space  

E-Print Network (OSTI)

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

A. N. Leznov

2007-07-23T23:59:59.000Z

194

The Effect of Temperature on the Deformation Structure of Single ...  

Science Conference Proceedings (OSTI)

THE EFFECT OF TEMPERATURE ON THE DEFORMATION STRUCTURE OF. SINGLE CRYSTAL NICKEL BASE SUPERALLOYS. M.Dollar' and I.M.Bernstein$.

195

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

Science Conference Proceedings (OSTI)

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.

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

196

Photonic gaps in cholesteric elastomers under deformation  

E-Print Network (OSTI)

Cholesteric liquid crystal elastomers have interesting and potentially very useful photonic properties. In an ideal monodomain configuration of these materials, one finds a Bragg-reflection of light in a narrow wavelength range and a particular circular polarization. This is due to the periodic structure of the material along one dimension. In many practical cases, the cholesteric rubber possesses a sufficient degree of quenched disorder, which makes the selective reflection broadband. We investigate experimentally the problem of how the transmittance of light is affected by mechanical deformation of the elastomer, and the relation to changes in liquid crystalline structure. We explore a series of samples which have been synthesized with photonic stop-gaps across the visible range. This allows us to compare results with detailed theoretical predictions regarding the evolution of stop-gaps in cholesteric elastomers.

P. Cicuta; A. R. Tajbakhsh; E. M. Terentjev

2004-08-27T23:59:59.000Z

197

Creep Behavior and Deformation Mechanisms for Nanocluster-Strengthened Ferritic Steels  

Science Conference Proceedings (OSTI)

Mechanically alloyed, nanostructured ferritic steels represent a class of alloys that can display high resistance to radiation and creep deformation, which are derived from the presence of nanoclusters, precipitates and solute segregation to the grain boundaries. The creep responses for a 14YWT nanostructured ferritic steel were measured over a range of temperatures and stress levels. The stress exponent was observed to vary non-linearly with applied stress; stress exponents were found to decrease with decreasing stress approaching unity at low stress. Transmission electron microscopy studies clearly demonstrated that creep deformation proceeds by a dislocation glide within nanoscale grains and that glide dislocations are attracted to and pinned by nanoclusters. In light of these observations, a new model of the creep response, inspired by the Kocks-Argon-Ashby model, is developed to explain the low creep rates and small stress exponents that are exhibited by these alloys.

Brandes, Matthew C [Ohio State University; Kovarik, L. [Ohio State University; Miller, Michael K [ORNL; Daehn, Glenn [Ohio State University; Mills, Michael J. [Ohio State University

2011-01-01T23:59:59.000Z

198

Deformed Coordinate-Space Hartree-Fock-Bogoliubov Approach to Weakly Bound Nuclei and Large Deformations  

E-Print Network (OSTI)

The coordinate space formulation of the Hartree-Fock-Bogoliubov (HFB) method enables self-consistent treatment of mean-field and pairing in weakly bound systems whose properties are affected by the particle continuum space. Of particular interest are neutron-rich, deformed drip-line nuclei which can exhibit novel properties associated with neutron skin. To describe such systems theoretically, we developed an accurate 2D lattice Skyrme-HFB solver {\\hfbax} based on B-splines. Compared to previous implementations, we made a number of improvements aimed at boosting the solver's performance. These include: explicit imposition of axiality and space inversion, use of the modified Broyden's method to solve self-consistent equations, and a partial parallelization of the code. {\\hfbax} has been benchmarked against other HFB solvers, both spherical and deformed, and the accuracy of the B-spline expansion was tested by employing the multiresolution wavelet method. Illustrative calculations are carried out for stable and ...

Pei, J C; Fann, G I; Nazarewicz, W; Schunck, N; Xu, F R

2008-01-01T23:59:59.000Z

199

DEFORMATION MODES OF PACKINGS OF FRICTIONLESS POLYDISPERSE SPHERES  

E-Print Network (OSTI)

1 DEFORMATION MODES OF PACKINGS OF FRICTIONLESS POLYDISPERSE SPHERES O. I. IMOLE, N. KUMAR, AND S as a function of volume fraction are reported for both uniaxial and deviatoric deformation modes. Our findings, and pressure (isotropic stress) are reported as function of volume fraction and isotropic strain, while

Luding, Stefan

200

Measurement and Modeling of High Strain-rate Deformation  

Science Conference Proceedings (OSTI)

... with Numerical Simulation Ě Using Huge Pendulum Impact Tester to Evaluate the Dynamic Fracture Toughness and Crack Behavior of Pipeline Steelsá...

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


201

Numerical Modelling of Creep Deformation in a CMSX-4 Single ...  

Science Conference Proceedings (OSTI)

performance of a cooled turbine blade which is subject to a loading ... the following flow rule for the ?? is employed: ??L12 .... the gas turbine. The primary loadsá...

202

Modeling Of Surface Deformation From Satellite Radar Interferometry...  

Open Energy Info (EERE)

field. The results are constrained with ground-based leveling observations. Two main subsidence areas are observed in the geothermal field, with maximum vertical and horizontal...

203

Modeling complex contacts involving deformable objects for haptic interaction.  

E-Print Network (OSTI)

??Haptic interaction allows a human user to touch and feel objects in virtual or remote environments with the tactile feedback as if he/she is handlingů (more)

Luo, Qi

204

Deformed Coordinate-Space Hartree-Fock-Bogoliubov Approach to Weakly Bound Nuclei and Large Deformations  

Science Conference Proceedings (OSTI)

The coordinate space formulation of the Hartree-Fock-Bogoliubov (HFB) method enables self-consistent treatment of mean field and pairing in weakly bound systems whose properties are affected by the particle continuum space. Of particular interest are neutron-rich, deformed drip-line nuclei which can exhibit novel properties associated with neutron skin. To describe such systems theoretically, we developed an accurate 2D lattice Skyrme-HFB solver HFB-AX based on B-splines. Compared to previous implementations, we made a number of improvements aimed at boosting the solver's performance. These include: explicit imposition of axiality and space inversion, use of the modified Broyden's method to solve self-consistent equations, and a partial parallelization of the code. HFB-AX has been benchmarked against other HFB solvers, both spherical and deformed, and the accuracy of the B-spline expansion was tested by employing the multi-resolution wavelet method. Illustrative calculations are carried out for stable and weakly bound nuclei at spherical and very deformed shapes, including constrained fission pathways. In addition to providing new physics insights, HFB-AX can serve as a useful tool to assess the reliability and applicability of coordinate-space and configuration-space HFB solvers, both existing and in development.

Pei, Junchen [ORNL; Stoitsov, M. V. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Fann, G. I. [Oak Ridge National Laboratory (ORNL); Nazarewicz, W. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Schunck, N. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Xu, F. R. [Peking University

2008-01-01T23:59:59.000Z

205

Deformed Coordinate-Space Hartree-Fock-Bogoliubov Approach to Weakly Bound Nuclei and Large Deformations  

E-Print Network (OSTI)

The coordinate space formulation of the Hartree-Fock-Bogoliubov (HFB) method enables self-consistent treatment of mean-field and pairing in weakly bound systems whose properties are affected by the particle continuum space. Of particular interest are neutron-rich, deformed drip-line nuclei which can exhibit novel properties associated with neutron skin. To describe such systems theoretically, we developed an accurate 2D lattice Skyrme-HFB solver {\\hfbax} based on B-splines. Compared to previous implementations, we made a number of improvements aimed at boosting the solver's performance. These include: explicit imposition of axiality and space inversion, use of the modified Broyden's method to solve self-consistent equations, and a partial parallelization of the code. {\\hfbax} has been benchmarked against other HFB solvers, both spherical and deformed, and the accuracy of the B-spline expansion was tested by employing the multiresolution wavelet method. Illustrative calculations are carried out for stable and weakly bound nuclei at spherical and very deformed shapes, including constrained fission pathways. In addition to providing new physics insights, {\\hfbax} can serve as a useful tool to assess the reliability and applicability of coordinate-space and configuration-space HFB solvers, both existing and in development.

J. C. Pei; M. V. Stoitsov; G. I. Fann; W. Nazarewicz; N. Schunck; F. R. Xu

2008-07-18T23:59:59.000Z

206

Mineral Deformation at Earth's Core-Mantle Boundary  

NLE Websites -- All DOE Office Websites (Extended Search)

Mineral Deformation at Earth's Core-Mantle Boundary Print Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to the deformation of the constituent minerals. To understand the deformation mechanisms of mineral phases at this depth, researchers from Yale and UC Berkeley re-created the ultrahigh pressures of the deep Earth at ALS Beamline 12.2.2 while conducting in situ x-ray diffraction experiments to probe changes in crystal orientations.

207

Surface Deformation from Satellite Data and Geothermal Assessment,  

Open Energy Info (EERE)

Surface Deformation from Satellite Data and Geothermal Assessment, Surface Deformation from Satellite Data and Geothermal Assessment, Exploration and Mitigation in Imperial Valley Jump to: navigation, search OpenEI Reference LibraryAdd to library Web Site: Surface Deformation from Satellite Data and Geothermal Assessment, Exploration and Mitigation in Imperial Valley Author Mariana Eneva Published N/A, 2012 DOI Not Provided Check for DOI availability: http://crossref.org Online Internet link for Surface Deformation from Satellite Data and Geothermal Assessment, Exploration and Mitigation in Imperial Valley Citation Mariana Eneva. Surface Deformation from Satellite Data and Geothermal Assessment, Exploration and Mitigation in Imperial Valley [Internet]. 2012. N/A. N/A. [cited 2013/09/17]. Available from: http://www.energy.ca.gov/research/notices/2012-02-29_workshop/presentations/Geothermal/Eneva-Imageair_Inc_Presentation.pdf

208

Mineral Deformation at Earth's Core-Mantle Boundary  

NLE Websites -- All DOE Office Websites (Extended Search)

Mineral Deformation at Earth's Core-Mantle Boundary Print Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to the deformation of the constituent minerals. To understand the deformation mechanisms of mineral phases at this depth, researchers from Yale and UC Berkeley re-created the ultrahigh pressures of the deep Earth at ALS Beamline 12.2.2 while conducting in situ x-ray diffraction experiments to probe changes in crystal orientations.

209

Deformed oscillator algebras and QFT in {kappa}-Minkowski spacetime  

SciTech Connect

In this paper, we study the deformed statistics and oscillator algebras of quantum fields defined in {kappa}-Minkowski spacetime. The twisted flip operator obtained from the twist associated with the star product requires an enlargement of the Poincare algebra to include the dilatation generators. Here we propose a novel notion of a fully covariant flip operator and show that to the first order in the deformation parameter it can be expressed completely in terms of the Poincare generators alone. The R matrices corresponding to the twisted and the covariant flip operators are compared up to first order in the deformation parameter and they are shown to be different. We also construct the deformed algebra of the creation and annihilation operators that arise in the mode expansion of a scalar field in {kappa}-Minkowski spacetime. We obtain a large class of such new deformed algebras which, for certain choice of realizations, reduce to results known in the literature.

Govindarajan, T. R.; Gupta, Kumar S.; Harikumar, E.; Meljanac, S.; Meljanac, D. [Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai 600113 (India); Theory Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Calcutta 700064 (India); School of Physics, University of Hyderabad, Hyderabad 500046 (India); Rudjer Boskovic Institute, Bijenicka c.54, HR-10002 Zagreb (Croatia)

2009-07-15T23:59:59.000Z

210

Mineral Deformation at Earth's Core-Mantle Boundary  

NLE Websites -- All DOE Office Websites (Extended Search)

Mineral Deformation at Earth's Core-Mantle Boundary Print Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to the deformation of the constituent minerals. To understand the deformation mechanisms of mineral phases at this depth, researchers from Yale and UC Berkeley re-created the ultrahigh pressures of the deep Earth at ALS Beamline 12.2.2 while conducting in situ x-ray diffraction experiments to probe changes in crystal orientations.

211

Dislocation decorrelation and relationship to deformation microtwins during creep of a precipitate strengthened Ni-based superalloy  

SciTech Connect

The evolution of microtwins during high temperature creep deformation in a strengthened Ni-base superalloy has been investigated through a combination of creep testing, transmission electron microscopy (TEM), theoretical modeling, and computer simulation. Experimentally, microtwin nucleation sources were identified and their evolution was tracked by characterizing the deformation substructure at different stages of creep deformation. Deformation is highly localized around stress concentrators such as carbides, borides and serrated grain boundaries, which act as sources of a/2<110> matrix-type dislocations. Due to fine channels between particles, coupled with the low matrix stacking fault energy, the a/2<110> matrix dislocations dissociate into a/6<112> Shockley partials, which were commonly observed to be decorrelated from one another, creating extended intrinsic stacking faults in the matrix. Microtwins are common and form via Shockley partial dislocations cooperatively shearing both and phases on adjacent {111} glide planes. The TEM observations lead directly to an analysis of dislocation-precipitate interactions. Through phase field simulations and theoretical analyses based on Orowan looping, the important processes of dislocation dissociation and decorrelation are modeled in detail, providing comprehensive insight into the microstructural features and applied stress conditions that favor the microtwinning deformation mode in strengthened Ni-based superalloys.

Unocic, Raymond R [ORNL; Zhou, Ning [Ohio State University; Kovarik, Libor [Pacific Northwest National Laboratory (PNNL); Shen, Chen [GE Global Research; Wang, Yunzhi [Ohio State University; Mills, Michael J. [Ohio State University

2011-01-01T23:59:59.000Z

212

Use of high-temperature, high-torque rheometry to study the viscoelastic properties of coal during carbonization  

SciTech Connect

When coal is heated in the absence of oxygen it softens at approximately 400 degrees C, becomes viscoelastic, and volatiles are driven off. With further heating, the viscous mass reaches a minimum viscosity in the range of 10{sup 3}-10{sup 5} Pa s and then begins to resolidify. A high-torque, high-temperature, controlled-strain rheometer with parallel plates has been used to study the theology during this process. Under shear, the viscosity of the softening mass decreases with increasing shear rate. During resolidification, the viscosity increases as C-C bond formation and physical interactions gives rise to an aromatic network, but, under shear, the network breaks apart and flows. This is viewed as a yielding of the structure. The higher the shear rate, the earlier the yielding occurs, such that if the shear rate is low enough, the structure is able to build. Also, further into resolidification lower shear rates are able to break the structure. It is proposed that resolidification occurs through the formation of aromatic clusters that grow and become crosslinked by non-covalent interactions. As the clusters grow, the amount of liquid surrounding them decreases and it is thought that the non-covalent interactions between clusters and liquid could decrease and the ability of growing clusters to move past each other increases, which would explain the weakening of the structure under shear. This work is part of a program of work aimed at attaining a greater understanding of microstructural changes taking place during carbonization for different coals, in order to understand the mechanisms that give rise to good quality cokes and coke oven problems such as excessive wall pressure.

Diaz, M.C.; Duffy, J.J.; Snape, C.E.; Steel, K.M. [University of Nottingham, Nottingham (United Kingdom)

2007-09-15T23:59:59.000Z

213

R E F E R E E D P A P E R Interactive Local Terrain Deformation Inspired by  

E-Print Network (OSTI)

into height maps using shader programs running on graphics hardware. The height field is edited indirectly. To further improve performance, we use a graphics processing unit implementation where a vertex shader computes the deformed positions of the model to be displayed. The vertex shader is a processing function

Kurapov, Alexander

214

Geometrically exact 3D beam element for arbitrary large rigid-elastic deformation analysis of aerospace structures  

Science Conference Proceedings (OSTI)

This paper presents a geometrically exact beam theory and a corresponding displacement-based finite-element formulation for modeling and analysis of highly flexible beam components of multibody systems undergoing huge static/dynamic rigid-elastic deformations. ... Keywords: Flexible multibody systems, Geometrically exact beam theory, Jaumann strains, Nonlinear finite element analysis, Nonlinear structural mechanics

Genyong Wu; Xingsuo He; P. Frank Pai

2011-04-01T23:59:59.000Z

215

Sand deformation concept for in-situ recovery of bitumen by cyclic steam injection  

SciTech Connect

Historically, a vertical or horizontal fracture is believed to be a main recovery mechanism for a cyclic steam injection process from the unconsolidated oil sands. Most of the current computer models for the process are based on the fracture concept. With the new postulated ''Sand Deformation Concept'' on the other hand, the injected fluid is able to penetrate the unconsolidated oil sand by creating microchannels. When the pore pressure is reduced during production, these secondary flow channels will totally or partially collapse. Condensed steam tends to sweep fluids where the bitumen had been heated and imparts mobility due to the injected hot fluid. Flow geometry of the new concept was fully investigated in this study. The physical differences between the sand deformation zone and the no-deformation zone were also investigated. The major differences zone were also investigated. The major differences between these two zones are a porosity change, a pressure level and energy and flow characteristics resulting from the existence of microchannels. All of these modifications were successfully incorporated into a conventional numerical thermal simulator. The new model provided an excellent match for all the field observations (steam injection pressure, oil-and-water production rates, fluid production temperature, downhole production pressure and the salinity changes) of a steam stimulated well in an unconsolidated oil sand. Conclusion from the study indicates that the most important phenomenon for in-situ recovery of bitumen is the one way valve effect of the microchannels which are opened during injection and closed during production.

Ito, Y.

1982-09-01T23:59:59.000Z

216

Time-aging time-stress superposition in soft glass under tensile deformation field  

E-Print Network (OSTI)

We have studied the tensile deformation behaviour of thin films of aging aqueous suspension of Laponite, a model soft glassy material, when subjected to a creep flow field generated by a constant engineering normal stress. Aqueous suspension of Laponite demonstrates aging behaviour wherein it undergoes time dependent enhancement of its elastic modulus as well as its characteristic relaxation time. However, under application of the normal stress, the rate of aging decreases and in the limit of high stress, the aging stops with the suspension now undergoing a plastic deformation. Overall, it is observed that the aging that occurs over short creep times at small normal stresses is same as the aging that occurs over long creep times at large normal stresses. This observation allows us to suggest an aging time - process time - normal stress superposition principle, which can predict rheological behaviour at longer times by carrying out short time tests.

Asima Shaukat; Ashutosh Sharma; Yogesh M. Joshi

2010-06-10T23:59:59.000Z

217

Quantum Theory at Planck Scale, Limiting Values, Deformed Gravity and Dark Energy Problem  

E-Print Network (OSTI)

Within a theory of the existing fundamental length on the order of Planck's a high-energy deformation of the General Relativity for the space with horizon has been constructed. On this basis, Markov's work of the early eighties of the last century has been given a new interpretation to show that the heuristic model considered by him may be placed on a fundamental footing. The obtained results have been applied to solving of the dark energy problem, making it possible to frame the following hypothesis: a dynamic cosmological term is a measure of deviation from a thermodynamic identity (the first law of thermodynamics) of the high-energy (Planck's) deformation of Einstein equations for horizon spaces in their thermodynamic interpretation.

A. E. Shalyt-Margolin

2011-02-24T23:59:59.000Z

218

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

Science Conference Proceedings (OSTI)

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.

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

219

Evaluation of seismic capacity of glovebox windows using deformation tests  

SciTech Connect

With the increasing emphasis on worker safety, gloveboxes are being relied upon in Safety Analyses to be a confinement boundary. Many of the accident scenarios result in a requirement that these gloveboxes be seismically qualified. Since there is currently no validated experience data category for gloveboxes, the qualification has generally been done by analysis. The weak link in assuring confinement integrity by analysis is in characterizing the glass and glass-to-glovebox seal in the analytical models. engineering judgement as to whether the windows will survive a seismic event based on total calculated deflection at the window. Most often the windows are assumed to lose their confinement capability during an earthquake. A quantitative basis is needed in order to evaluate the seismic capacity of these windows. A series of deformation tests are being performed at the Savannah River Site on glovebox mock-ups. This paper presents the results of the first two of these tests, including displacement profiles and leak rate data. Methods for using this data for evaluating the windows for seismic loads are proposed.

Hargett, S.T.

1995-12-31T23:59:59.000Z

220

Theoretical analysis for the optical deformation of emulsion droplets  

E-Print Network (OSTI)

We propose a theoretical framework to predict the three-dimensional shapes of optically deformed micron-sized emulsion droplets with ultra-low interfacial tension. The resulting shape and size of the droplet arises out of a balance between the interfacial tension and optical forces. Using an approximation of the laser field as a Gaussian beam, working within the Rayleigh-Gans regime and assuming isotropic surface energy at the oil-water interface, we numerically solve the resulting shape equations to elucidate the three-dimensional droplet geometry. We obtain a plethora of shapes as a function of the number of optical tweezers, their laser powers and positions, surface tension, initial droplet size and geometry. Experimentally, two-dimensional droplet silhouettes have been imaged from above, but their full side-on view has not been observed and reported for current optical configurations. This experimental limitation points to ambiguity in differentiating between droplets having the same two-dimensional projection but with disparate three-dimensional shapes. Our model elucidates and quantifies this difference for the first time. We also provide a dimensionless number that indicates the shape transformation (ellipsoidal to dumbbell) at a value $\\approx 1.0$, obtained by balancing interfacial tension and laser forces, substantiated using a data collapse.

David Tapp; Jonathan M. Taylor; Alex S. Lubanksy; Colin D. Bain; Buddhapriya Chakrabarti

2013-08-13T23:59:59.000Z

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


221

Why are the interband transitions among triaxially strongly deformed bands suppressed in even nuclei?  

Science Conference Proceedings (OSTI)

As top-on-top model has made a great success in explaining triaxially strongly deformed (TSD) bands in odd-A nuclei, we extend this model to even-A nuclei, i.e. two particles in different single-particle orbitals outside the triaxial rotor. In the lowest order approximation, the electromagnetic transitions between TSD bands in even-A case are reduced by a factor of 0.04 compared with odd-A case. It is one of the reasons why TSD bands are not yet explicitly observed in even-A nuclei.

Sugawara-Tanabe, Kazuko [Otsuma Women's University, Tama, Tokyo 206-8540 (Japan); Theoretical Nuclear Physics Laboratory, RIKEN Nishina Center, Wako, Saitama 351-0198 (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)

2011-05-06T23:59:59.000Z

222

Applications of Radar Interferometry to Detect Surface Deformation in  

Open Energy Info (EERE)

Applications of Radar Interferometry to Detect Surface Deformation in Applications of Radar Interferometry to Detect Surface Deformation in Geothermal Areas of Imperial Valley in Southern California Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Applications of Radar Interferometry to Detect Surface Deformation in Geothermal Areas of Imperial Valley in Southern California Abstract InSAR (interferometric synthetic aperture radar) is applied in Imperial Valley of southern California to detect and characterize surface deformation in existing geothermal fields, possible future geothermal developments, and around faults. The data used are from the Envisat satellite, collected over the period 2003-2010. The specific InSAR technique applied, SqueeSARTM, identifies permanent and distributed scatterers (PS and DS), which play the role of numerous benchmarks

223

Kinematics of compressional and extensional ductile shearing deformation in  

Open Energy Info (EERE)

Kinematics of compressional and extensional ductile shearing deformation in Kinematics of compressional and extensional ductile shearing deformation in a metamorphic core complex of the northeastern basin and range Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Kinematics of compressional and extensional ductile shearing deformation in a metamorphic core complex of the northeastern basin and range Details Activities (1) Areas (1) Regions (0) Abstract: Analysis of shear criteria enables the kinematics of two main ductile-shearing events (D1 and D2) to be established in the Raft River, Grouse Creek and Albion 'metamorphic core complex'. The first event (D1) is a NNE-thrusting and corresponds to Mesozoic shortening. A well developed non-coaxial ductile deformation (D2), of Cenozoic age, is marked by the occurrence of opposing eastward (in Raft River) and westward shear

224

Geodetic Constraints on Contemporary Deformation in the Northern Walker  

Open Energy Info (EERE)

Geodetic Constraints on Contemporary Deformation in the Northern Walker Geodetic Constraints on Contemporary Deformation in the Northern Walker Lane: 2. Velocity and Strain Rate Tensor Analysis- In: Late Cenozoic Structure and Evolution of the Great Basin-Sierra Nevada Transition Jump to: navigation, search OpenEI Reference LibraryAdd to library Book Section: Geodetic Constraints on Contemporary Deformation in the Northern Walker Lane: 2. Velocity and Strain Rate Tensor Analysis- In: Late Cenozoic Structure and Evolution of the Great Basin-Sierra Nevada Transition Abstract Abstract unavailable Authors C. Kreemer, Geoffrey Blewitt and William C. Hammond Editors John S. Oldow and Patricia H. Cashman Published Geological Society of America, 2009 DOI Not Provided Check for DOI availability: http://crossref.org Online Internet link for Geodetic Constraints on Contemporary Deformation

225

Deformation Mechanisms in Carbon Nanotube/Epoxy Composites  

Science Conference Proceedings (OSTI)

Presentation Title, Deformation Mechanisms in Carbon Nanotube/Epoxy Composites ... fracture toughness and delamination damage resistance, and the associated ... Effect of Piassava Fiber Incorporation In Morphological, Thermal and ... Semiconductors: Producing Bulk Sized Nanocomposites Using Electric Currentsá...

226

3D deformation field throughout the interior of materials.  

SciTech Connect

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.

Jin, Huiqing; Lu, Wei-Yang

2013-09-01T23:59:59.000Z

227

Superconductivity with deformed Fermi surfaces and compact stars  

E-Print Network (OSTI)

I discuss the deformed Fermi surface superconductivity (DFS) and some of its alternatives in the context of nucleonic superfluids and two flavor color superconductors that may exist in the densest regions of compact stellar objects.

Armen Sedrakian

2003-12-15T23:59:59.000Z

228

Deformation Field and Microstructure of Copper in Flat Punch ...  

Science Conference Proceedings (OSTI)

A Study on the Stress Test of Truck Frames for Freight Trains Ě A Study on the ... Defect Energetics and Fission Product Transport in ZrC Ě Deformation Field andá...

229

Wavefront control in space with MEMS deformable mirrors  

E-Print Network (OSTI)

To meet the high contrast requirement of 1 Î 10[superscript ?10] to image an Earth-like planet around a Sun-like star, space telescopes equipped with coronagraphs require wavefront control systems. Deformable mirrors (DMs) ...

Cahoy, Kerri L.

230

Do halos exist on the dripline of deformed nuclei?  

E-Print Network (OSTI)

A study of the effect of deformation and pairing on the development of halo nuclei is presented. Exploratory three-body $core+n+n$ calculations show that both the NN interaction and the deformation/excitation of the core hinder the formation of the halo. Preliminary self-consistent mean-field calculations are used to search for regions in the nuclear chart where halos could potentially develop. These are also briefly discussed.

Nunes, F M; Duguet, T

2005-01-01T23:59:59.000Z

231

DEFORMATIONS OF MAASS FORMS D.W. Farmer  

E-Print Network (OSTI)

DEFORMATIONS OF MAASS FORMS D.W. Farmer S. Lemurell Abstract. We describe numerical calculations, deformations, Phillips┬şSarnak conjecture, Teichmuller space Typeset by A M S┬şT E X 1 #12; 2 D.W. FARMER S the surfaces on which we performed our calcula┬ş tions. #12; 4 D.W. FARMER S. LEMURELL 2.1 Subgroups of PSL(2, R

Lemurell, Stefan

232

TDHF fusion calculations for spherical+deformed systems  

E-Print Network (OSTI)

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.

A. S. Umar; V. E. Oberacker

2006-04-04T23:59:59.000Z

233

Theory of microdroplet and microbubble deformation by Gaussian laser beam  

E-Print Network (OSTI)

The theory for linear deformations of fluid microparticles in a laser beam of Gaussian profile is presented, when the beam focus is at the particle center as in optical trapping. Three different fluid systems are considered: water microdroplet in air, air microbubble in water, and a special oil-emulsion in water system used in experiments with optical deformation of fluid interfaces. We compare interface deformations of the three systems when illuminated by a wide (compared to particle radius) and narrow laser beams and analyse differences. Deformations of droplets are radically different from bubbles under otherwise identical conditions, due to the opposite lensing effect (converging and diverging, respectively) of the two; a droplet is deformed far more than a bubble, cetera paribus. Optical contrast is found to be of great importance to the shape obtained when comparing the relatively low-contrast oil-emulsion system to that of water droplets. We finally analyse the dynamics of particle motion when the laser beam is turned on, and compare a static beam to the case of a short pulse. The very different surface tension coefficient implies a very different time scale for dynamics: microseconds for the water-air interface and tens of milliseconds for the oil-emulsion. Surface oscillations of a water microdroplet are found always to be underdamped, while those of the oil-emulsion are overdamped; deformations of a microbubble can be either, depending on physical parameters.

Simen ┼ Ellingsen

2012-12-12T23:59:59.000Z

234

High Temperature Deformation of Inconel 718 Castings  

Science Conference Proceedings (OSTI)

the computer model to yield the predicted cooling history of the casting, determine the numerically ... 10% HN03, and 5% acetic acid. Figure 1 shows a typicalá...

235

Assessment of Crystallographic Deformation Behaviors in Aluminum ...  

Science Conference Proceedings (OSTI)

N11: Microbilogically Influenced Corrosion of Pipeline Steels used in Oil & Gas Industry ... N2: Fabrication of Uranium Dispersion Targets for Mo-99 Production ... Numerical Modelling for Characterising the Flammability of Natural Fibreá...

236

Signature splitting in $^{173}$W with triaxial particle rotor model  

E-Print Network (OSTI)

A particle rotor model with a quasi-neutron coupled with a triaxially deformed rotor is applied to study signature splitting for bands with intruder orbital $\

B. Qi; S. Q. Zhang; S. Y. Wang; J. Meng

2008-06-15T23:59:59.000Z

237

Signature splitting in $^{173}$W with triaxial particle rotor model  

E-Print Network (OSTI)

A particle rotor model with a quasi-neutron coupled with a triaxially deformed rotor is applied to study signature splitting for bands with intruder orbital $\

Qi, B; Wang, S Y; Meng, J

2008-01-01T23:59:59.000Z

238

Thermal-Mechanical Fatigue Life Model for Coated Superalloy ...  

Science Conference Proceedings (OSTI)

in an aggressive combustion gas environment. Coating ..... M.I. Wood and G.F. Harrison, "Modeling The Deformation Of Coated. Superalloys Under Thermalá...

239

Phase Structure and Cyclic Deformation in Eutectic Tin-Lead Alloy: A Numerical Analysis  

Science Conference Proceedings (OSTI)

This study is devoted to providing a mechanistic rationale of coarsening induced failure in solder alloys during thermomechanical fatigue. Micromechanical modeling of cyclic deformation of eutectic tin-lead alloy was undertaken using the finite element method. The models consist of regularly arranged tin-rich and lead-rich phases, simulating the lamellar array and colony structure in a typical eutectic system. A fine structure and a coarse structure, bearing the same phase fraction but different in the aspect ratio of each lead-rich layer and in the number of lead-rich layers in each colony, are utilized for representing the microstructure before and after coarsening, respectively. Both phases are treated as elastic-plastic solids with their respective properties. For simplicity the creep effect is ignored without compromising the main objective of this study. Cyclic loading under pure shear and uniaxial conditions is modeled. It is found that both the fine and coarse structures exhibit essentially the same macroscopic stress-strain response. The coarse structure, however, shows a greater maximum effective plastic strain on a local scale throughout the deformation. The numerical result implies that, in a solder joint, a locally coarsened region may not be mechanically weaker than its surrounding, but it is subject to early damage initiation due to accumulated plasticity. Other implications regarding solder alloy failure and micromechanical modeling of two-phase materials are discussed.

FANG,HUEI ELIOT; Li,W; SHEN,Y.-L

1999-09-09T23:59:59.000Z

240

Texture enhanced appearance models  

Science Conference Proceedings (OSTI)

Statistical region-based registration methods such as the active appearance model (AAM) are used for establishing dense correspondences in images. At low resolution, images correspondences can be recovered reliably in real-time. However, as resolution ... Keywords: Active appearance models, Atlases, Deformable models, Dimensionality reduction, Face images, Registration, Wavelets, Wedgelets

Rasmus Larsen; Mikkel B. Stegmann; Sune Darkner; S°ren Forchhammer; Timothy F. Cootes; Bjarne KjÝr Ersb°ll

2007-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "viscoelastic deformation model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Contemporary Tectonic Deformation of the Basin and Range Province, Western  

Open Energy Info (EERE)

Contemporary Tectonic Deformation of the Basin and Range Province, Western Contemporary Tectonic Deformation of the Basin and Range Province, Western United States: 10 Years of Observation with the Global Positioning System Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Contemporary Tectonic Deformation of the Basin and Range Province, Western United States: 10 Years of Observation with the Global Positioning System Abstract [1] We have estimated patterns and rates of crustal movement across 800 km of the Basin and Range at Ôł╝39┬░ north latitude with Global Positioning System surveys in 1992, 1996, 1998, and 2002. The total rate of motion tangent to the small circle around the Pacific-North America pole of rotation is 10.4 ┬▒ 1.0 mm/yr, and motion normal to this small circle is 3.9 ┬▒ 0.9 mm/yr compared to the east end of our network. On the Colorado

242

Deformation and tribology of multi-walled hollow nanoparticles  

E-Print Network (OSTI)

Multi-walled hollow nanoparticles made from tungsten disulphide (WS$_2$) show exceptional tribological performance as additives to liquid lubricants due to effective transfer of low shear strength material onto the sliding surfaces. Using a scaling approach based on continuum elasticity theory for shells and pairwise summation of van der Waals interactions, we show that van der Waals interactions cause strong adhesion to the substrate which favors release of delaminated layers onto the surfaces. For large and thin nanoparticles, van der Waals adhesion can cause considerable deformation and subsequent delamination. For the thick WS$_2$ nanoparticles, deformation due to van der Waals interactions remains small and the main mechanism for delamination is pressure which in fact leads to collapse beyond a critical value. We also discuss the effect of shear flow on deformation and rolling on the substrate.

U. S. Schwarz; S. Komura; S. A. Safran

2000-05-01T23:59:59.000Z

243

Thermodynamics of a photon gas and deformed dispersion relations  

E-Print Network (OSTI)

We resort to the methods of statistical mechanics in order to determine the effects that a deformed dispersion relation has upon the thermodynamics of a photon gas. The ensuing modifications to the density of states, partition function, pressure, internal energy, entropy, and specific heat are calculated. It will be shown that the breakdown of Lorentz invariance can be interpreted as a repulsive interaction, among the photons. Additionally, it will be proved that the presence of a deformed dispersion relation entails an increase in the entropy of the system. In other words, as a consequence of the loss of the aforementioned symmetry the number of microstates available to the corresponding equilibrium state grows.

A. Camacho; A. Macias

2007-02-28T23:59:59.000Z

244

Vacuum Energy Problem, Fundamental Length and Deformed Quantum Field Theory  

E-Print Network (OSTI)

The cosmological constant (vacuum energy) problem is analyzed within the scope of quantum theories with UV-cut-off or fundamental length. Various cases associated with the appearance of the latter are considered both using the Generalized Uncertainty Relations and the deformed density matrix,previously introduced in the author's works. The use of the deformed density matrix is examined in detail. It is demonstrated that, provided the Fischler-Susskind cosmic holographic conjecture is valid, the Vacuum Energy Density takes a value close to the experimental one. The arguments supporting the validity of this conjecture are given on the basis of the recently obtained results on Gravitational Holography.

A. E. Shalyt-Margolin

2007-12-19T23:59:59.000Z

245

Thermal stability and strength of deformation microstructures in pure copper  

SciTech Connect

The plastic flow field produced by machining is utilized to access a range of deformation parameters in pure copper: strains of 1ľ7, strain rates of 1ľ1000 s?1 and temperatures as low as 77 K. The strength and stability of the severe plastic deformation microstructures including cellular, elongated, equiaxed and twinned types are characterized. Unique combinations of strengthening and stability are identified in the case of heavily twinned microstructures. These observations offer insights for improving the stability of both single-phase and multicomponent ultrafine-grained alloys.

Saldana, C.; King, Alex H.; Chandrasekar, S.

2012-05-18T23:59:59.000Z

246

Shape of {sup 44}Ar: Onset of deformation in neutron-rich nuclei near {sup 48}Ca  

Science Conference Proceedings (OSTI)

The development of deformation and shape coexistence in the vicinity of doubly magic {sup 48}Ca, related to the weakening of the N=28 shell closure, was addressed in a low-energy Coulomb excitation experiment using a radioactive {sup 44}Ar beam from the SPIRAL facility at GANIL. The 2{sub 1}{sup +} and 2{sub 2}{sup +} states in {sup 44}Ar were excited on {sup 208}Pb and {sup 109}Ag targets at two different beam energies. B(E2) values between all observed states and the spectroscopic quadrupole moment of the 2{sub 1}{sup +} state were extracted from the differential Coulomb excitation cross sections, indicating a prolate shape of the {sup 44}Ar nucleus and giving evidence of an onset of deformation already two protons and two neutrons away from doubly magic {sup 48}Ca. New Hartree-Fock-Bogoliubov based configuration mixing calculations have been performed with the Gogny D1S interaction for {sup 44}Ar and neighboring nuclei using two different approaches: the angular momentum projected generator coordinate method considering axial quadrupole deformations and a five-dimensional approach including the triaxial degree of freedom. The experimental values and new calculations are furthermore compared to shell-model calculations and to relativistic mean-field calculations. The new results give insight into the weakening of the N=28 shell closure and the development of deformation in this neutron-rich region of the nuclear chart.

Zielinska, M. [CEA Saclay, IRFU, Service de Physique Nucleaire, F-91191 Gif-sur-Yvette (France); Heavy Ion Laboratory, University of Warsaw, PL-02-093 Warsaw (Poland); Goergen, A.; Clement, E.; Korten, W.; Dossat, C.; Ljungvall, J.; Obertelli, A.; Theisen, Ch. [CEA Saclay, IRFU, Service de Physique Nucleaire, F-91191 Gif-sur-Yvette (France); Delaroche, J.-P.; Girod, M. [CEA, DAM, DIF, F-91297 Arpajon (France); Buerger, A. [CEA Saclay, IRFU, Service de Physique Nucleaire, F-91191 Gif-sur-Yvette (France); Helmholtz Institut fuer Strahlen-und Kernphysik, Universitaet Bonn, D-53115 Bonn (Germany); Catford, W. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Iwanicki, J.; Napiorkowski, P. J.; Srebrny, J.; Wrzosek, K. [Heavy Ion Laboratory, University of Warsaw, PL-02-093 Warsaw (Poland); Libert, J. [Institut de Physique Nucleaire, IN2P3-CNRS/Universite Paris-Sud, F-91406 Orsay (France); PiePtak, D. [II WeiTI, Warsaw University of Technology (Poland); Rodriguez-Guzman, R. [Department of Physics, University of Jyvaeskylae, P. O. Box 35, FI-40014 Jyvaeskylae (Finland); Sletten, G. [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark)

2009-07-15T23:59:59.000Z

247

DEFORMATION AND FRACTURE OF POLYCRYSTALLINE LITHIUM FLUORIDE (thesis)  

SciTech Connect

Techniques for forming polycrystalline LiF from the melt and for fabricating test specimens were developed and evaluated using single-crystal LiF as a control. Large -grain polycrystalline specimens tested in fourpoint loading always showed some plastic deformation (0.078 to 0.798%) before fracture, but the plastic flow was sharpiy reduced from that of single crystals. An etch was developed revealing dislocations on all crystallographic faces of LiF. Details of plastic deformation in polycrystalline material were investigated. Deformation was inhomogeneous among the grains of an aggregate because of differences in orientation with respect to the applied stress, also within individual grains because of interactions between adjoining grains. Grain boundaries were barriers to slip, but stresses resulting from slip in one grain were transmitted to neighboring grains and often caused local deformation near the boundary. Because of local stresses, local slip systems operated although the resolved shear stresses on them from the applied load were below the critical yield stress. In one case, slip occurred on an (010) plane. Three-grain junctions were areas of high residual stress. Fractures originated at boundaries at or near 3-grain junctions, not as a result of inherent boundary weakness but rather because of high stresses developed at the boundary. A quantitative expression for fracture originating in a slip band was applied to one type of fracture. (auth)

Scott, W.D.

1962-09-14T23:59:59.000Z

248

Qubit dynamics in a q-deformed oscillators environment  

E-Print Network (OSTI)

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.

S. L'Innocente; C. Lupo; S. Mancini

2009-12-19T23:59:59.000Z

249

Underwater locomotion from oscillatory shape deformations Patricio A. Vela  

E-Print Network (OSTI)

Underwater locomotion from oscillatory shape deformations Patricio A. Vela , Kristi A. Morgansen@robotics.caltech.edu Abstract: This paper considers underwater propulsion that is generated by variations in body shape. We underwater vehicles that propel and steer themselves by changes in shape (e.g. [11, 13, 15

Sontag, Eduardo

250

Dr. John J. Stephens, Jr. Memorial Symposium: Deformation and ...  

Science Conference Proceedings (OSTI)

Papers are solicited in the areas of creep and deformation of metals, ... Effect of the Cr, Si and B on the Oxidation Behavior of three Nb-base Alloys ... Processing of Small-grain Bulk W-4 wt% Ni Alloy by Mechanical Milling and Sintering.

251

Validating an imaging and analysis system for assessing torso deformities  

Science Conference Proceedings (OSTI)

We present the results of the numeric and functional validation of an imaging and analysis system used for assessing human torsos for deformities such as scoliosis. The system comprises of image acquisition, image reconstruction, and shape analysis components. ... Keywords: 3D surface measurement, Laser digitizer, Non-invasive measurement, Scoliosis, Torso imaging, Trunk asymmetry

Peter O. Ajemba; Nelson G. Durdle; Doug L. Hill; V. James Raso

2008-03-01T23:59:59.000Z

252

Large Deformation Constitutive Laws for Isotropic Thermoelastic Materials  

Science Conference Proceedings (OSTI)

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

Plohr, Bradley J. [Los Alamos National Laboratory; Plohr, Jeeyeon N. [Los Alamos National Laboratory

2012-07-25T23:59:59.000Z

253

Deformation potentials of CdSe quantum dots  

E-Print Network (OSTI)

a v (in eV) of zinc-blende CdSe. SEPM PW PW+d a a LAPW Expt>4: The size dependence of Ś a of C B M state of CdSe QDs. vDeformation potentials of CdSe quantum dots Jingbo L i and L

Li, Jingbo; Wang, Lin-Wang

2004-01-01T23:59:59.000Z

254

Thermomechanical Characterization and Modeling of Shape Memory Polymers  

E-Print Network (OSTI)

This work focuses on the thermomechanical characterization and constitutive model calibration of shape memory polymers (SMPs). These polymers have the ability to recover seemingly permanent large deformations under the appropriate thermomechanical load path. In this work, a contribution is made to both existing experimental and modeling efforts. First, an experimental investigation is conducted which subjects SMPs to a thermomechanical load path that includes varying the value of applied deformations and temperature rates. Specifically, SMPs are deformed to tensile extensions of 10% to 100% at temperature rates varying from 1 degree C /min to 5 degree C/min, and the complete shape recovery profile is captured. The results from this experimental investigation show that the SMP in question can recover approximately 95% of the value of the applied deformation, independent of the temperature rate during the test. The data obtained in the experimental investigation are then used to calibrate, in one-dimension, two constitutive models which have been developed to describe and predict the material response of SMPs. The models include a model in terms of general deformation gradients, thus making it capable of handling large deformations. In addition, the data are used to calibrate a linearized version of the constitutive model for small deformations. The material properties required for calibrating the constitutive models are derived from portions of the experimental results, and the model is then used to predict the shape memory effect for an SMP undergoing various levels of deformation. The model predictions are shown to match well with the experimental data.

Volk, Brent L.

2009-05-01T23:59:59.000Z

255

Development of experimental verification techniques for non-linear deformation and fracture on the nanometer scale.  

SciTech Connect

This work covers three distinct aspects of deformation and fracture during indentations. In particular, we develop an approach to verification of nanoindentation induced film fracture in hard film/soft substrate systems; we examine the ability to perform these experiments in harsh environments; we investigate the methods by which the resulting deformation from indentation can be quantified and correlated to computational simulations, and we examine the onset of plasticity during indentation testing. First, nanoindentation was utilized to induce fracture of brittle thin oxide films on compliant substrates. During the indentation, a load is applied and the penetration depth is continuously measured. A sudden discontinuity, indicative of film fracture, was observed upon the loading portion of the load-depth curve. The mechanical properties of thermally grown oxide films on various substrates were calculated using two different numerical methods. The first method utilized a plate bending approach by modeling the thin film as an axisymmetric circular plate on a compliant foundation. The second method measured the applied energy for fracture. The crack extension force and applied stress intensity at fracture was then determined from the energy measurements. Secondly, slip steps form on the free surface around indentations in most crystalline materials when dislocations reach the free surface. Analysis of these slip steps provides information about the deformation taking place in the material. Techniques have now been developed to allow for accurate and consistent measurement of slip steps and the effects of crystal orientation and tip geometry are characterized. These techniques will be described and compared to results from dislocation dynamics simulations.

Moody, Neville Reid; Bahr, David F.

2005-11-01T23:59:59.000Z

256

An efficient correction procedure via reconstruction for simulation of viscous flow on moving and deforming domains  

Science Conference Proceedings (OSTI)

In this paper, we report the development of a new parallel solver using the Correction Procedure via Reconstruction (CPR) for viscous flows on moving and deforming grids. By employing an accurate treatment of flux derivatives for moving and deforming ... Keywords: Correction procedure via reconstruction, Moving and deforming grids, Parallel Navier-Stokes solver, Quadrilateral element, Unstructured grid

Chunlei Liang, Koji Miyaji, Bin Zhang

2014-01-01T23:59:59.000Z

257

Original article: Numerical simulation of two-phase flow in deformable porous media: Application to carbon dioxide storage in the subsurface  

Science Conference Proceedings (OSTI)

In this paper, conceptual modeling as well as numerical simulation of two-phase flow in deep, deformable geological formations induced by CO"2 injection are presented. The conceptual approach is based on balance equations for mass, momentum and energy ... Keywords: Carbon capture storage (CCS), Heat transport, OpenGeoSys (OGS), Porous media, Two-phase flow consolidation

O. Kolditz; S. Bauer; N. B÷Ttcher; D. Elsworth; U. -J. G÷Rke; C. -I. Mcdermott; C. -H. Park; A. K. Singh; J. Taron; W. Wang

2012-06-01T23:59:59.000Z

258

Defect-deformation mechanism of the size effect in the laser-induced formation of microstructures of the brass surface relief in liquid  

Science Conference Proceedings (OSTI)

It is shown that the model of the defect-deformation instability describes the recently found linear dependence of the period of ordered surface relief microstructures, produced on brass in liquid upon multipulse laser ablation, on the radius of the spot on the target surface. (letters)

Emel'yanov, V I [M. V. Lomonosov Moscow State University, Faculty of Physics, Moscow (Russian Federation)

2008-07-31T23:59:59.000Z

259

The introduction of the microchanneling phenomenon to cyclic steam stimulation and its application to the numerical simulator (sand deformation concept)  

SciTech Connect

Historically, a vertical or horizontal fracture is believed to be a main recovery mechanism for a cyclic steam-injection process in unconsolidated oil sands. Most current computer models for the process are based on the fracture concept. With the postulated sand deformation concept, on the other hand, the injected fluid is able to penetrate the unconsolidated oil sand by creating microchannels. When the pore pressure is reduced during production, these secondary flow channels will collapse totally or partially. Condensed steam tends to sweep fluids where the bitumen had been heated and imparts mobility as a result of the injected hot fluid. Flow geometry of the new concept is described in this paper. The physical differences between the sand deformation zone and the no-deformation zone are also investigated. The three major differences between these two zones are porosity change, pressure level, and energy and flow characteristics resulting from the existence of microchannels. All these modifications were incorporated successfully into a conventional numerical thermal simulator. The new model provided an excellent match for all the field observations (steam-injection pressure, oil-and-water production rates, fluid production temperature, downhole production pressure, and salinity changes) of a steam-stimulated well in an unconsolidated oil sand. The study indicates that the most important phenomenon for in-situ recovery of bitumen is the one-way-valve effect of the microchannels, which are opened during injection and closed during production.

Ito, Y.

1984-08-01T23:59:59.000Z

260

Nuclear deformation effect on the binding energies in heavy ions  

E-Print Network (OSTI)

Nuclear deformation effects on the binding energies in heavy ions are investigated. Approximate formulas for the nuclear-size correction and the isotope shift for deformed nuclei are derived. Combined with direct numerical evaluations, these formulas are employed to reanalyse experimental data on the nuclear-charge-distribution parameters in $^{238}\\textrm{U}$ and to revise the nuclear-size corrections to the binding energies in H- and Li-like $^{238}\\textrm{U}$. As a result, the theoretical uncertainties for the ground-state Lamb shift in $^{238}\\textrm{U}^{91+}$ and for the $2p_{1/2}-2s$ transition energy in $^{238}\\textrm{U}^{89+}$ are significantly reduced. The isotope shift of the $2p_{j}-2s$ transition energies for $^{142}\\textrm{Nd}^{57+}$ and $^{150}\\textrm{Nd}^{57+}$ is also evaluated including nuclear size and nuclear recoil effects within a full QED treatment.

Kozhedub, Y S; Shabaev, V M; Tupitsyn, I I; Brandau, C; Kozhuharov, C; Plunien, G; St÷hlker, T

2007-01-01T23:59:59.000Z

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


261

2008 Rock Deformation GRC - Conference August 3-8, 2008  

Science Conference Proceedings (OSTI)

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.

James G. Hirth

2009-09-21T23:59:59.000Z

262

Structural Deformation during a Typhoon as Monitored by an Integrated Multi-Sensor System  

E-Print Network (OSTI)

Monitoring structural response induced by severe loadings such as typhoon is an efficient way to mitigate or prevent damage. Because the measured signal can be used to activate an alarm system to evacuate people from an endangered building, or to drive a control system to suppress typhoon excited vibrations so as to protect the integrity of the structure. A 108m tall tower in Tokyo has been monitored by an integrated system combining RTK-GPS and accelerometers. Data collected by the multi-sensor system have been analysed and compared to the original finite element modelling (FEM) result for structural deformation monitoring studies. Especially, the short time Fast Fourier Transform (FFT) analysis results have shown that the time-frequency relation does give us almost instantaneous frequency response during a typhoon event. In this paper the feasibility of integrating advanced sensing technologies such as RTK-GPS with traditional accelerometer sensors, for structural vibration response and deformation monitoring under severe loading conditions, is discussed. The redundancy within the integrated system has shown robust quality assurance.

Xiaojing Li

2004-01-01T23:59:59.000Z

263

Physical Simulation of an Embedded Surface Mesh Involving Deformation and Fracture  

E-Print Network (OSTI)

Simulating virtual objects which can deform or break apart within their environments is now common in state-of-the-art virtual simulations such as video games or surgery simulations. Real-time performance requires a physical model which provides an approximation to the true solution for fast computations but at the same time provides enough believability of the simulation to the user. Recent research in object deformation and fracture has revolved around embedding portions of the simulation for graphical display inside a much simpler physical domain which is invisible to the user. Embedding complex geometry in a simpler domain allows for very complex effects to occur in a much more robust and computationally efficient manner. This thesis explores a novel method to efficiently embed a high-resolution surface mesh inside a coarse tetrahedral physical mesh for the purposes of interactive simulation and display. A technique to display interior regions as solid geometry without explicitly re-meshing the graphical mesh during fracture has been explored and developed. Keeping the graphical mesh static in memory during simulation allows the geometry to be off-loaded to the GPU while shaders can be utilized to only display portions of the geometry which are locally contained within the physical mesh. Recent advances in GPU technology have also been exploited in order to provide an increase in visual fidelity and help achieve the illusion that the virtual object itself is breaking apart in a physically plausible manner.

Clack, Billy

2012-05-01T23:59:59.000Z

264

Effects of cryogenic equal channel angular deformation on copper 101  

E-Print Network (OSTI)

Grain size in polycrystalline metallic materials significantly influences physical and mechanical properties. At room temperature, large grain size is generally associated with low strength, hardness and ductility. Fine grained microstructures show an increase in strength due to a larger grain boundary surface area per unit volume. One way to obtain fine grained microstructures is through cold working and recrystallization of the material. In this study, oxygen-free high-conductivity copper 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 special ECAD tool was designed and built, which was capable of operating under the high loads resulting from forcing a billet through the die at -196 ░C. Hardness, tensile strength, electrical resistivity and annealing experiments were performed following deformation along with optical microscopy and transmission electron microscopy (TEM) to observe changes in properties and grain morphology.

Horan, Christopher Sean

2001-01-01T23:59:59.000Z

265

In-situ neutron diffraction and crystal plasticity modeling of ?-Uranium  

Science Conference Proceedings (OSTI)

The present study uses a combination of in-situ neutron diffraction and crystal plasticity modeling to elucidate the deformation mechanisms active in ?-Uranium.

266

Models  

E-Print Network (OSTI)

Ľ A very typical statistical/econometric model assumes something like yt ? i.i.d. f (y, x, ?) (1) where f (Ě) is a parametric family known up to parameters ?. Ľ Parameter estimation: maximum likelihood ł?n = arg max ? ln f (Yt, Xt, ?) (2) t Ľ What if the basic model assumptions of (1) are violated? The parametric family may not contain the true model f0(x, y) that generated the data; or the data may not be i.i.d.; etc. Misspecified

Stas Kolenikov; U Of Missouri; U Of Missouri

2007-01-01T23:59:59.000Z

267

Halos in a deformed relativistic Hartree-Bogoliubov theory in continuum  

Science Conference Proceedings (OSTI)

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.

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

268

Modeling Time-dependent Responses of Piezoelectric Fiber Composite  

E-Print Network (OSTI)

The existence of polymer constituent in piezoelectric fiber composites (PFCs) could lead to significant viscoelastic behaviors, affecting overall performance of PFCs. High mechanical and electrical stimuli often generate significant amount of heat, increasing temperatures of the PFCs. At elevated temperatures, most materials, especially polymers show pronounced time-dependent behaviors. Predicting time-dependent responses of the PFCs becomes important to improve reliability in using PFCs. We study overall performance of PFCs having unidirectional piezoceramic fibers, such as PZT fibers, dispersed in viscoelastic polymer matrix. Two types of PFCs are studied, which are active fiber composites (AFCs) and macro fiber composites (MFCs). AFCs and MFCs consist of unidirectional PZT fibers dispersed in epoxy placed between two interdigitated electrode and kapton layers. The AFCs have a circular fiber cross-section while the MFCs have a square fiber cross-section. Finite element (FE) models of representative volume elements (RVEs) of active PFCs, having square and circular fiber cross-sections, are generated for composites with 20, 40, and 60 percent fiber contents. Two FE micromechanical models having one fiber embedded in epoxy matrix and five fibers placed in epoxy matrix are considered. A continuum 3D piezoelectric element in ABAQUS FE is used. A general time-integral function is applied for the mechanical, electrical, and piezoelectric properties in order to incorporate the time-dependent effect and histories of loadings. The effective properties of PZT-5A/epoxy and PZT-7A/LaRC-SI piezocomposites determined from the FE micromechanical models are compared to available experimental data and analytical solutions in the literature. Furthermore, the effect of viscoelastic behaviors of the LaRC-SI matrix at an elevated temperature on the overall electro-mechanical and piezoelectric constants are examined.

Li, Kuo-An

2009-12-01T23:59:59.000Z

269

A Simple Model of Droplet Spectral Evolution during Turbulent Mixing  

Science Conference Proceedings (OSTI)

The mixing of cloudy, saturated air with cloud-free, subsaturated air is examined with a simple one-dimensional model of the mixing process. The model incorporates (i) a one-dimensional parameterization of turbulent deformation, (ii) molecular ...

J°rgen B. Jensen; Marcia B. Baker

1989-09-01T23:59:59.000Z

270

Mechanical deformation of monocytic THP-1 cells : occurrence of two seqential phases with differential sensitivity to metabolic inhibitors  

E-Print Network (OSTI)

Blood leukocytes can exhibit extensive morphological changes during their passage through small capillary vessels. The human monocytic THP-1 cell line was used to explore the metabolic dependence of these shape changes. Cells were aspirated into micropipettes for determination of the rate of protrusion formation. They were then released and the kinetics of morphological recovery was studied. Results were consistent with Evans' model (Blood, 64 : 1028, 1984) of a viscous liquid droplet surrounded by a tensile membrane. The estimated values of cytoplasmic viscosity and membrane tension were 162 Pa.s and 0.0142 millinewton/m respectively. The influence of metabolic inhibitors on cell mechanical behaviour was then studied : results strongly suggested that deformation involved two sequential phases. The cell elongation rate measured during the first 30 seconds following the onset of aspiration was unaffected by azide, an inhibitor of energy production, and it was about doubled by cytochalasin D, a microfilament inhibitor, and colchicine, a microtubule inhibitor. However, during the following two minutes, deformation was almost abolished in cells treated with azide and cytochalasin D, whereas the protrusion of control cells exhibited about threefold length increase. It is concluded that, although cells seemed to deform as passive objects, active metabolic processes were required to allow extensive morphological changes triggered by external forces.

Pierre Bongrand; Anne-Marie Benoliel; Fabienne Richelme

2007-11-15T23:59:59.000Z

271

Metric deformation and boundary value problems in 3D  

E-Print Network (OSTI)

A novel perturbative method, proposed by Panda {\\it et al.} [1] to solve the Helmholtz equation in two dimensions, is extended to three dimensions for general boundary surfaces. Although a few numerical works are available in the literature for specific domains in three dimensions such a general analytical prescription is presented for the first time. An appropriate transformation is used to get rid of the asymmetries in the domain boundary by mapping the boundary into an equivalent sphere with a deformed interior metric. The deformed metric produces new source terms in the original homogeneous equation. A deformation parameter measuring the deviation of the boundary from a spherical one is introduced as a perturbative parameter. With the help of standard Rayleigh-Schr{\\"o}dinger perturbative technique the transformed equation is solved and the general solution is written down in a closed form at each order of perturbation. The solutions are boundary condition free and which make them widely applicable for various situations. Once the boundary conditions are applied to these general solutions the eigenvalues and the wavefunctions are obtained order by order. The efficacy of the method has been tested by comparing the analytic values against the numerical ones for three dimensional enclosures of various shapes. The method seems to work quite well for these shapes for both, Dirichlet as well as Neumann boundary conditions. The usage of spherical harmonics to express the asymmetries in the boundary surfaces helps us to consider a wide class of domains in three dimensions and also their fast convergence guarantees the convergence of the perturbative series for the energy. Direct applications of this method can be found in the field of quantum dots, nuclear physics, acoustical and electromagnetic cavities.

Subhasis Panda; S. Pratik Khastgir

2013-07-24T23:59:59.000Z

272

Coupled reservoir-geomechanical analysis of CO2 injection and ground deformations at In Salah, Algeria  

SciTech Connect

In Salah Gas Project in Algeria has been injecting 0.5-1 million tonnes CO{sub 2} per year over the past five years into a water-filled strata at a depth of about 1,800 to 1,900 m. Unlike most CO{sub 2} storage sites, the permeability of the storage formation is relatively low and comparatively thin with a thickness of about 20 m. To ensure adequate CO{sub 2} flow-rates across the low-permeability sand-face, the In Salah Gas Project decided to use long-reach (about 1 to 1.5 km) horizontal injection wells. In an ongoing research project we use field data and coupled reservoir-geomechanical numerical modeling to assess the effectiveness of this approach and to investigate monitoring techniques to evaluate the performance of a CO{sub 2}-injection operation in relatively low permeability formations. Among the field data used are ground surface deformations evaluated from recently acquired satellite-based inferrometry (InSAR). The InSAR data shows a surface uplift on the order of 5 mm per year above active CO{sub 2} injection wells and the uplift pattern extends several km from the injection wells. In this paper we use the observed surface uplift to constrain our coupled reservoir-geomechanical model and conduct sensitivity studies to investigate potential causes and mechanisms of the observed uplift. The results of our analysis indicates that most of the observed uplift magnitude can be explained by pressure-induced, poro-elastic expansion of the 20 m thick injection zone, but there could also be a significant contribution from pressure-induced deformations within a 100 m thick zone of shaly sands immediately above the injection zone.

Rutqvist, J.; Vasco, D.W.; Myer, L.

2009-11-01T23:59:59.000Z

273

Exotic modes of excitation in deformed neutron-rich nuclei  

SciTech Connect

Low-lying dipole excitation mode in neutron-rich Mg isotopes close to the drip line is investigated in the framework of the Hartree-Fock-Bogoliubov and the quasiparticle random-phase approximation employing the Skyrme and the pairing energy-density functionals. It is found that the low-lying dipole-strength distribution splits into the K{sup {pi}} = 0{sup -} and 1{sup -} components due to the nuclear deformation. The low-lying dipole strength increases as the neutron drip-line is approached.

Yoshida, Kenichi [RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198 (Japan)

2011-05-06T23:59:59.000Z

274

Modeling  

NLE Websites -- All DOE Office Websites (Extended Search)

ALE-AMR ALE-AMR code Wangyi Liu, John Bernard, Alex Friedman, Nathan Masters, Aaron Fisher, Velemir Mlaker, Alice Koniges, David Eder June 4, 2011 Abstract In this paper we describe an implementation of a single-fluid inter- face model in the ALE-AMR code to simulate surface tension effects. The model does not require explicit information on the physical state of the two phases. The only change to the existing fluid equations is an additional term in the stress tensor. We show results of applying the model to an expanding Al droplet surrounded by an Al vapor, where additional droplets are created. 1 Introduction The Neutralized Drift Compression Experiment II (NDCX II) is an induction accelerator planned for initial commissioning in 2012. The final design calls for a 3 MeV, Li+ ion beam, delivered in a bunch with characteristic pulse duration of 1 ns, and transverse dimension of order 1 mm. The

275

The $?$-deformed Segal-Bargmann transform is a Hall type transform  

E-Print Network (OSTI)

We present an explanation of how the $\\mu$-deformed Segal-Bargmann spaces, that are studied in various articles of the author in collaboration with Angulo, Echevarria and Pita, can be viewed as deserving their name, that is, how they should be considered as a part of Segal-Bargmann analysis. This explanation relates the $\\mu$-deformed Segal-Bargmann transforms to the generalized Segal-Bargmann transforms introduced by B. Hall using heat kernel analysis. All the versions of the $\\mu$-deformed Segal-Bargmann transform can be understood as Hall type transforms. In particular, we define a $\\mu$-deformation of Hall's "Version C" generalized Segal-Bargmann transform which is then shown to be a $\\mu$-deformed convolution with a $\\mu$-deformed heat kernel followed by analytic continuation. Our results are generalizations and analogues of the results of Hall.

Stephen Bruce Sontz

2007-07-30T23:59:59.000Z

276

Effect of Starting Grain Size on As-Deformed Microstructure in High ...  

Science Conference Proceedings (OSTI)

This work was conducted by the National Center for Excellence in ... In high temperature deformation of alloy 718, the major event is ... this investigation. The twoá...

277

Anisotropy of the Fracture Behaviour of Severly Deformed Iron and a ...  

Science Conference Proceedings (OSTI)

Anisotropy of the Fracture Behaviour of Severly Deformed Iron and a Pearlitic Rail Steel Ě Atom Probe Tomography: A New Insight into the Partition andá...

278

Collision Detection and Merging of Deformable B-Spline Surfaces in Virtual Reality Environment.  

E-Print Network (OSTI)

??This thesis presents a computational framework for representing, manipulating and merging rigid and deformable freeform objects in virtual reality (VR) environment. The core algorithms forů (more)

Pungotra, Harish

2010-01-01T23:59:59.000Z

279

Failure Loads and Deformation in 6061-T6 Aluminum Alloy Spot ...  

Science Conference Proceedings (OSTI)

Presentation Title, Failure Loads and Deformation in 6061-T6 Aluminum Alloy ... Application of Neutron Diffraction in Analysis of Residual Stress Profile in theá...

280

Postseismic deformation of the Andaman Islands following the 26 December, 2004 Great SumatraAndaman earthquake  

E-Print Network (OSTI)

sensing and visual inspection of shoreline changes provide evidence for both uplift and subsidence and Rundle, 1979; Fialko, 2004]. Laboratory deformation experiments leave little doubt that all three

Bilham, Roger

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


281

Numerical simulation of flow for viscoelastic neutrophil models in a rectangular capillary network: Effects of capillary shape and cell stiffness on transit time  

Science Conference Proceedings (OSTI)

The concentration of neutrophils in the pulmonary microvasculature is higher than in large systemic vessels. It is thought that the high concentration of neutrophils facilitates their effective recruitment to sites of inflammation. Thus, in order to ...

Atsushi Shirai; Ryo Fujita; Toshiyuki Hayase

2007-04-01T23:59:59.000Z

282

Particle Deformation and Concentration Polarization in Electroosmotic Transport of Hydrogels through Pores  

SciTech Connect

In this article, we report detection of deformable, hydrogel particles by the resistive-pulse technique using single pores in a polymer film. The hydrogels pass through the pores by electroosmosis and cause formation of a characteristic shape of resistive pulses indicating the particles underwent dehydration and deformation. These effects were explained via a non-homogeneous pressure distribution along the pore axis modeled by the coupled Poisson-Nernst-Planck and Navier Stokes equations. The local pressure drops are induced by the electroosmotic fluid flow. Our experiments also revealed the importance of concentration polarization in the detection of hydrogels. Due to the negative charges as well as branched, low density structure of the hydrogel particles, concentration of ions in the particles is significantly higher than in the bulk. As a result, when electric field is applied across the membrane, a depletion zone can be created in the vicinity of the particle observed as a transient drop of the current. Our experiments using pores with openings between 200 and 1600 nm indicated the concentration polarization dominated the hydrogels detection for pores wider than 450 nm. The results are of importance for all studies that involve transport of molecules, particles and cells through pores with charged walls. The developed inhomogeneous pressure distribution can potentially influence the shape of the transported species. The concentration polarization changes the interpretation of the resistive pulses; the observed current change does not necessarily reflect only the particle size but also the size of the depletion zone that is formed in the particle vicinity.

Vlassiouk, Ivan V [ORNL

2013-01-01T23:59:59.000Z

283

Including realistic tidal deformations in binary black-hole initial data  

E-Print Network (OSTI)

A shortcoming of current binary black-hole initial data is the generation of spurious gravitational radiation, so-called junk radiation, when they are evolved. This problem is a consequence of an oversimplified modeling of the binary's physics in the initial data. Since junk radiation is not astrophysically realistic, it contaminates the actual waveforms of interest and poses a numerical nuisance. The work here presents a further step towards mitigating and understanding the origin of this issue, by incorporating post-Newtonian results in the construction of constraint-satisfying binary black-hole initial data. Here we focus on including realistic tidal deformations of the black holes in the initial data, by building on the method of superposing suitably chosen black hole metrics to compute the conformal data. We describe the details of our initial data for an equal-mass and nonspinning binary, compute the subsequent relaxation of horizon quantities in evolutions, and quantify the amount of junk radiation that is generated. These results are contrasted with those obtained with the most common choice of conformally flat (CF) initial data, as well as superposed Kerr-Schild (SKS) initial data. We find that when realistic tidal deformations are included, the early transients in the horizon geometries are significantly reduced, along with smaller deviations in the relaxed black hole masses and spins from their starting values. Likewise, the junk radiation content in the $l=2$ modes is reduced by a factor of $\\sim$1.7 relative to CF initial data, but only by a factor of $\\sim$1.2 relative to SKS initial data. More prominently, the junk radiation content in the $3\\leq l\\leq8$ modes is reduced by a factor of $\\sim$5 relative to CF initial data, and by a factor of $\\sim$2.4 relative to SKS initial data.

Tony Chu

2013-10-29T23:59:59.000Z

284

Accumulated Dose in Liver Stereotactic Body Radiotherapy: Positioning, Breathing, and Deformation Effects  

Science Conference Proceedings (OSTI)

Purpose: To investigate the accumulated dose deviations to tumors and normal tissues in liver stereotactic body radiotherapy (SBRT) and investigate their geometric causes. Methods and Materials: Thirty previously treated liver cancer patients were retrospectively evaluated. Stereotactic body radiotherapy was planned on the static exhale CT for 27-60 Gy in 6 fractions, and patients were treated in free-breathing with daily cone-beam CT guidance. Biomechanical model-based deformable image registration accumulated dose over both the planning four-dimensional (4D) CT (predicted breathing dose) and also over each fraction's respiratory-correlated cone-beam CT (accumulated treatment dose). The contribution of different geometric errors to changes between the accumulated and predicted breathing dose were quantified. Results: Twenty-one patients (70%) had accumulated dose deviations relative to the planned static prescription dose >5%, ranging from -15% to 5% in tumors and -42% to 8% in normal tissues. Sixteen patients (53%) still had deviations relative to the 4D CT-predicted dose, which were similar in magnitude. Thirty-two tissues in these 16 patients had deviations >5% relative to the 4D CT-predicted dose, and residual setup errors (n = 17) were most often the largest cause of the deviations, followed by deformations (n = 8) and breathing variations (n = 7). Conclusion: The majority of patients had accumulated dose deviations >5% relative to the static plan. Significant deviations relative to the predicted breathing dose still occurred in more than half the patients, commonly owing to residual setup errors. Accumulated SBRT dose may be warranted to pursue further dose escalation, adaptive SBRT, and aid in correlation with clinical outcomes.

Velec, Michael, E-mail: michael.velec@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Institute of Medical Science, University of Toronto, Toronto, ON (Canada); Moseley, Joanne L. [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Craig, Tim [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Dawson, Laura A.; Brock, Kristy K. [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Institute of Medical Science, University of Toronto, Toronto, ON (Canada)

2012-07-15T23:59:59.000Z

285

Deformability of shredded tires. Final report, 1996--1998  

Science Conference Proceedings (OSTI)

This report describes tree separate studies that examine the deformability of shredded tire fill material: The first study determined the response of shredded tires to cyclic loading. These tests were conducted in a load frame on both constrained and unconstrained samples and showed that the material became stiffer with increasing load; The second study focused on the long-term creep settlements of constrained and unconstrained samples. The results indicate that creep exists for a period of up to two years after loading; The third study investigated the possible anisotropic properties in the material. A larger modulus of elasticity was found in directions parallel to the layers than in the direction perpendicular to the layers. However, settlements computed using a representative anisotropic shredded tire fill material indicate that the current settlement analysis, based on isotropic shredded tire layers, predicts maximum settlements conservatively.

Drescher, A.; Newcomb, D.; Heimdahl, T.

1999-01-01T23:59:59.000Z

286

Scaling properties of sea ice deformation from buoy dispersion P. Rampal,1,2  

E-Print Network (OSTI)

in a gas or two people in a crowd, two nearby pieces of sea ice gradually move apart and disperse [MartinScaling properties of sea ice deformation from buoy dispersion analysis P. Rampal,1,2 J. Weiss,1 D. The deformation is derived from the dispersion of pairs of drifting buoys, using the IABP (International Arctic

Lindsay, Ron

287

GEOL534: Mechanics of Lithospheric Deformation Course organiser: Profs. J. P. Platt and T. W. Becker  

E-Print Network (OSTI)

1 GEOL534: Mechanics of Lithospheric Deformation Course organiser: Profs. J. P. Platt and T. W semester, 2009. Summary. This is an introductory course on the mechanical aspects of lithospheric for the mechanical description of deformational processes at both lithospheric and mantle scales, and how

Becker, Thorsten W.

288

Literature survey on cements for remediation of deformed casing in geothermal wells  

DOE Green Energy (OSTI)

Brookhaven National Laboratory was requested to conduct a literature survey for the best available cement to use in the proposed casing patch as part of the Geothermal Drilling Organization (GDO) project on remediation of deformed casings. A total of 50 wells have been identified with deformed production casing in Unocal`s portion of The Geysers geothermal field. A procedure to address the casing deformation and avoid abandonment of these wells has been developed as described in the Geysers Deformed Casing Remediation Proposal. The proposed remediation procedure involves isolation of the zone of interest with an inflatable packer, milling the deformed casing and cementing a 7 inch diameter liner to extend approximately 100 ft above and 100 ft below the milled zone. During the milling operation it is possible that the original cement and surrounding formation may slough away. In order to specify a suitable cement formulation for the casing patch it is first necessary to identify and understand the deformation mechanism/s operating in The Geysers field. Subsequently, the required cement mechanical properties to withstand further deformation of the repaired system must be defined. From this information it can be determined whether available cement formulations meet these requirements. In addition to The Geysers, other geothermal fields are at possible risk of casing deformation due to subsidence, seismic activity, lateral and vertical formation movement or other processes. Therefore, the proposed remediation procedure may have applications in other fields.

Allan, M.L.; Philippacopoulos, A.J.

1998-12-31T23:59:59.000Z

289

Modular and deformable touch-sensitive surfaces based on time domain reflectometry  

Science Conference Proceedings (OSTI)

Time domain reflectometry, a technique originally used in diagnosing cable faults, can also locate where a cable is being touched. In this paper, we explore how to extend time domain reflectometry in order to touch-enable thin, modular, and deformable ... Keywords: TDR, capacitive sensing, deformable, input, time domain reflectometry, touch sensing, wearable

Raphael Wimmer; Patrick Baudisch

2011-10-01T23:59:59.000Z

290

Steel Processing Properties and Their Effect on Impact Deformation of Lightweight Structures  

SciTech Connect

The objective of the research was to perform a comprehensive computational analysis of the effects of material and process modeling approaches on performance of UltraLight Steel Auto Body (ULSAB) vehicle models. The research addressed numerous material related effects, impact conditions as well as analyzed the performance of the ULSAB vehicles in crashes against designs representing the current US vehicle fleet. This report is organized into three main sections. The first section describes the results of the computational analysis of ULSAB crash simulations that were performed using advanced material modeling techniques. The effects of strain-rate sensitivity on a high strength steel (HSS) intensive vehicle were analyzed. Frontal and frontal offset crash scenarios were used in a finite element parametric study of the ULSAB body structure. Comparisons are made between the crash results using the piece-wise-linear isotropic plasticity strain-rate dependent material model, and the isotropic plasticity material model based on quasi-static properties. The simulation results show the importance of advanced material modeling techniques for vehicle crash simulations due to strain-rate sensitivity and rapid hardening characteristics of advanced high strength steels. Material substitution was investigated for the main frontal crush structure using the material of similar yield stress a significantly different strain-rate and hardening characteristics. The objective of the research presented in Section 2 was to assess the influence of stamping process on crash response of ULSAB vehicle. Considered forming effects included thickness variations and plastic strain hardening imparted in the part forming process. The as-formed thickness and plastic strain for front crash parts were used as input data for vehicle crash analysis. Differences in structural performance between crash models with and without forming data were analyzed in order to determine the effects and feasibility of integration of forming processes and crash models. Computational analysis of vehicle-to-vehicle crashes between ULSAB and conventional car designs is reported in Section 3. The study involved vehicles of comparable weights and dimensions to assess the compatibility of the ULSAB with existing designs. Deformation and acceleration data for crashed vehicles were analyzed. Vehicle-modeling approaches have strong influence on computational results and the requirements for compatibility of models were identified for future research on vehicle-to-vehicle crash modeling.

Simunovic, S

2003-09-23T23:59:59.000Z

291

Dynamic estimation of three-dimensional cerebrovascular deformation from rotational angiography  

Science Conference Proceedings (OSTI)

Purpose: The objective of this study is to investigate the feasibility of detecting and quantifying 3D cerebrovascular wall motion from a single 3D rotational x-ray angiography (3DRA) acquisition within a clinically acceptable time and computing from the estimated motion field for the further biomechanical modeling of the cerebrovascular wall. Methods: The whole motion cycle of the cerebral vasculature is modeled using a 4D B-spline transformation, which is estimated from a 4D to 2D+t image registration framework. The registration is performed by optimizing a single similarity metric between the entire 2D+t measured projection sequence and the corresponding forward projections of the deformed volume at their exact time instants. The joint use of two acceleration strategies, together with their implementation on graphics processing units, is also proposed so as to reach computation times close to clinical requirements. For further characterizing vessel wall properties, an approximation of the wall thickness changes is obtained through a strain calculation. Results: Evaluation on in silico and in vitro pulsating phantom aneurysms demonstrated an accurate estimation of wall motion curves. In general, the error was below 10% of the maximum pulsation, even in the situation when substantial inhomogeneous intensity pattern was present. Experiments on in vivo data provided realistic aneurysm and vessel wall motion estimates, whereas in regions where motion was neither visible nor anatomically possible, no motion was detected. The use of the acceleration strategies enabled completing the estimation process for one entire cycle in 5-10 min without degrading the overall performance. The strain map extracted from our motion estimation provided a realistic deformation measure of the vessel wall. Conclusions: The authors' technique has demonstrated that it can provide accurate and robust 4D estimates of cerebrovascular wall motion within a clinically acceptable time, although it has to be applied to a larger patient population prior to possible wide application to routine endovascular procedures. In particular, for the first time, this feasibility study has shown that in vivo cerebrovascular motion can be obtained intraprocedurally from a 3DRA acquisition. Results have also shown the potential of performing strain analysis using this imaging modality, thus making possible for the future modeling of biomechanical properties of the vascular wall.

Zhang Chong; Villa-Uriol, Maria-Cruz; De Craene, Mathieu [Department of Information and Communication Technologies (DTIC), Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Universitat Pompeu Fabra, E08018 Barcelona (Spain); and others

2011-03-15T23:59:59.000Z

292

Localized Deformation as a Primary Cause of Irradiation Assisted Stress Corrosion Cracking  

SciTech Connect

The objective of this project is to determine whether deformation mode is a primary factor in the mechanism of irradiation assisted intergranular stress corrosion cracking of austenitic alloys in light watert reactor core components. Deformation mode will be controlled by both the stacking fault energy of the alloy and the degree of irradiation. In order to establish that localized deformation is a major factor in IASCC, the stacking fault energies of the alloys selected for study must be measured. Second, it is completely unknown how dose and SFE trade-off in terms of promoting localized deformation. Finally, it must be established that it is the localized deformation, and not some other factor that drives IASCC.

Gary S. Was

2009-03-31T23:59:59.000Z

293

Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations  

E-Print Network (OSTI)

multiphase fluid flow, heat transfer, and deformation in fractured porousmultiphase fluid flow, heat transfer and deformation in porousmultiphase flow of brine and gas through saline media. Transport in Porous

Rutqvist, J.

2011-01-01T23:59:59.000Z

294

A Deformable Object Tracking Algorithm Based on the Boundary Element Method that is Robust to Occlusions and Spurious Edges  

Science Conference Proceedings (OSTI)

The manipulation of deformable objects is an important problem in robotics and arises in many applications including biomanipulation, microassembly, and robotic surgery. For some applications, the robotic manipulator itself may be deformable. Vision-based ... Keywords: Artificial neural networks, Boundary element method, Deformable object tracking, Edge detection, Robust statistics, Robust tracking

Michael A. Greminger; Bradley J. Nelson

2008-06-01T23:59:59.000Z

295

Modeling the mechanical behavior of amorphous metals by shear transformation zone dynamics  

E-Print Network (OSTI)

A new mesoscale modeling technique for the thermo-mechanical behavior of amorphous metals is proposed. The modeling framework considers the shear transformation zone (STZ) as the fundamental unit of deformation, and ...

Homer, Eric Richards, 1980-

2010-01-01T23:59:59.000Z

296

Probing the origin of inertia behind spacetime deformation  

E-Print Network (OSTI)

To investigate the origin and nature of inertia, we introduce a new concept of hypothetical 2D, so-called, "master-space" (MS), subject to certain rules. The MS, embedded in the background 4D-spacetime, is an indispensable individual companion to the particle of interest, without relation to every other particle. We argue that a deformation/(distortion of local internal properties) of MS is the origin of inertia. With this perspective in sight, we construct the alternative relativistic theory of inertia (RTI), which allows to compute the relativistic inertial force acting on an arbitrary point-like observer due to its "absolute acceleration". We go beyond the hypothesis of locality with an emphasis on distortion of MS, which allows to improve essentially the standard metric and other relevant geometrical structures related to the noninertial reference frame of an arbitrary accelerated observer. We compute the inertial force exerted on the photon in a gravitating system in the semi-Riemann space. Despite the t...

Ter_Kazarian, Gagik

2011-01-01T23:59:59.000Z

297

Probing the origin of inertia behind spacetime deformation  

E-Print Network (OSTI)

To investigate the origin and nature of inertia, we introduce a new concept of hypothetical 2D, so-called, "master-space" (MS), subject to certain rules. The MS, embedded in the background 4D-spacetime, is an indispensable individual companion to the particle of interest, without relation to every other particle. We argue that a deformation/(distortion of local internal properties) of MS is the origin of inertia. With this perspective in sight, we construct the alternative relativistic theory of inertia (RTI), which allows to compute the relativistic inertial force acting on an arbitrary point-like observer due to its "absolute acceleration". We go beyond the hypothesis of locality with an emphasis on distortion of MS, which allows to improve essentially the standard metric and other relevant geometrical structures related to the noninertial reference frame of an arbitrary accelerated observer. We compute the inertial force exerted on the photon in a gravitating system in the semi-Riemann space. Despite the totally different and independent physical sources of gravitation and inertia, this approach furnishes justification for the introduction of the principle of equivalence. Consequently, we relate the inertia effects to the more general post-Riemannian geometry. We derive a general expression of the relativistic inertial force exerted on the extended spinning body moving in the Rieman-Cartan space.

Gagik Ter-Kazarian

2011-05-30T23:59:59.000Z

298

Solid modeling techniques to build 3D finite element models of volcanic systems: An example from the Rabaul Caldera system, Papua New Guinea  

Science Conference Proceedings (OSTI)

Simulating the deformation of active volcanoes is challenging due to inherent mechanical complexities associated with heterogeneous distributions of rheologic properties and irregular geometries associated with the topography and bathymetry. From geologic ... Keywords: 3D geometry, Deformation, Finite Elements Models, Rabaul Caldera

Erika Ronchin, Timothy Masterlark, Joan MartÝ Molist, Steve Saunders, Wei Tao

2013-03-01T23:59:59.000Z

299

Electro-hydraulic forming of advanced high-strength steels: Deformation and microstructural characterization  

SciTech Connect

This conference manuscript describes mechanical and microstructural characterization of steel sheets that were deformed via the electro-hydraulic forming technique. The manuscripts shows the importance of the experimental technique developed at PNNL in the sense that the deformation history information enabled by this technique is not obtainable through existing conventional approaches. Additionally, strain-rate effects on texture development during sheet-forming at high-rates are described. Thus, we have demonstrated that it is now possible to correlate deformation history with microstructural development during high-rate forming, a capability that is unique to PNNL.

Rohatgi, Aashish; Stephens, Elizabeth V.; Edwards, Danny J.; Smith, Mark T.; Davies, Richard W.

2012-06-08T23:59:59.000Z

300

Role of deformation on giant resonances within the QRPA approach and the Gogny force  

E-Print Network (OSTI)

Fully consistent axially-symmetric-deformed Quasi-particle Random Phase Approximation (QRPA) calculations have been performed, in which the same Gogny D1S effective force has been used for both the Hartree-Fock-Bogolyubov mean field and the QRPA approaches. Giant resonances calculated in deformed $^{26-28}$Si and $^{22-24}$Mg nuclei as well as in the spherical $^{30}$Si and $^{28}$Mg isotopes are presented. Theoretical results for isovector-dipole and isoscalar monopole, quadrupole, and octupole responses are presented and the impact of the intrinsic nuclear deformation is discussed.

S. Peru; H. Goutte

2008-04-01T23:59:59.000Z

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


301

Effect of uniaxial deformation to 50% on the sensitization process in 316 stainless steel  

Science Conference Proceedings (OSTI)

The effect of uniaxial deformation to 50% on the degree of sensitization (DOS) in 316 stainless steel was investigated at 625 and 670 deg. C for 5-100 h using the electrochemical potentiokinetic reactivation (EPR) test. The results showed that the deformation accelerated the sensitization/desensitization process, especially at 670 deg. C. However, the material is still sensitized after up to 100 h of aging time. Transmission electron microscopy was used to corroborate these results. The deformed material showed more carbide precipitates (Cr{sub 23}C{sub 6}) at the grain boundaries and twin intersections than did the nondeformed material.

Ramirez, L.M. [Instituto Tecnologico de Saltillo Departamento de Metal-Mecanica Blvd. V. Carranza 2400, Saltillo Coah, CP 25280 (Mexico); Almanza, E. [Instituto Tecnologico de Saltillo Departamento de Metal-Mecanica Blvd. V. Carranza 2400, Saltillo Coah, CP 25280 (Mexico); Murr, L.E. [University of Texas at El Paso, Department of Metallurgical and Materials Engineering, El Paso, TX 79968 (United States)]. E-mail: fekberg@utep.edu

2004-09-15T23:59:59.000Z

302

Development of Dislocation Structure under Shear Deformation in ...  

Science Conference Proceedings (OSTI)

First Principles Modeling of Shape Memory Alloy Magnetic Refrigeration Materials ... of Lithium Battery Materials LiMPO4 (M = Mn, Fe, Co, and Ni): A Comparative ... Forming-Crush Simulation Optimization Using Internal State Variable Model.

303

Structural Properties and Deformation Patterns of Evolving Strike ...  

Science Conference Proceedings (OSTI)

model generalizes the strain energy function of a solid to account for first-order ..... represent the rheology of the crystalline crust (CARTER and TSENN, 1987) and a ... computed throughout the model domain, both plan views (including depthá...

304

Multi-Strain Induced Deformation Twin in Nanocrystalline Copper  

Science Conference Proceedings (OSTI)

First Principles Modeling of Shape Memory Alloy Magnetic Refrigeration Materials ... Different Generations of Gamma Prime Precipitates in a Commercial Nickelá...

305

Role of material properties and mesostructure on dynamic deformation and shear instability in Al-W granular composites  

E-Print Network (OSTI)

Dynamic experiments with Al-W granular/porous composites revealed qualitatively different behavior with respect to shear localization depending on bonding between Al particles. Two-dimensional numerical modeling was used to explore the mesomechanics of the large strain dynamic deformation in Al-W granular/porous composites and explain the experimentally observed differences in shear localization between composites with various mesostructures. Specifically, the bonding between the Al particles, the porosity, the roles of the relative particle sizes of Al and W, the arrangements of the W particles, and the material properties of Al were investigated using numerical calculations. It was demonstrated in simulations that the bonding between the "soft" Al particles facilitated shear localization as seen in the experiments. Numerical calculations and experiments revealed that the mechanism of the shear localization in granular composites is mainly due to the local high strain flow of "soft" Al around the "rigid" W particles causing localized damage accumulation and subsequent growth of the meso/macro shear bands/cracks. The "rigid" W particles were the major geometrical factor determining the initiation and propagation of "kinked" shear bands in the matrix of "soft" Al particles, leaving some areas free of extensive plastic deformation as observed in experiments and numerical calculations.

K. L. Olney; P. H. Chiu; C. W. Lee; V. F. Nesterenko; D. J. Benson

2011-05-24T23:59:59.000Z

306

Short-lived binary splits of an excited projectile-like fragment induced by transient deformation  

Science Conference Proceedings (OSTI)

Aligned fragment emission associated with peripheral and midperipheral dissipative collisions of {sup 124}Xe+{sup 124}Sn at E/A=50 MeV is examined. Binary decay of the excited projectile-like fragment (PLF*) is correlated with significant velocity damping from the projectile velocity. Both a forward emission component, attributed to standard statistical emission, and a backward component are observed. The backward component arises from both statistical and dynamical decay processes. This backward component manifests a strong alignment with the direction of the PLF* velocity and is found to depend sensitively on the atomic number of the light fragment, Z{sub L}, and the velocity of the PLF{sup *}. The yield of the backward component is significantly enhanced relative to the forward component. The composition of fragments emitted in the backward direction reveals that a correlation between alignment and neutron excess exists for fragments with Z<8. From the measured asymmetry of the angular distributions, the angular distribution for dynamical fragment emission is deduced. Comparison with a schematic one-dimensional Langevin model allows extraction of both the magnitude and the dependence on Z{sub L} of the transient initial deformation of the PLF*. Fragment emission times of the order of 0.25-1.5x10{sup -21} s are extracted.

McIntosh, A. B.; Hudan, S.; Black, J.; Mercier, D.; Metelko, C. J.; Yanez, R.; Souza, R. T. de; Chbihi, A.; Famiano, M.; Fregeau, M. O.; Gauthier, J.; Moisan, J.; Roy, R.; Bianchin, S.; Schwarz, C.; Trautmann, W. [Department of Chemistry and Indiana University Cyclotron Facility 2401 Milo B. Sampson Lane, Bloomington, Indiana 47405 (United States); GANIL, Caen (France); Western Michigan University, Kalamazoo, Michigan (United States); Universite Laval, Quebec (Canada); GSI Helmholtzzentrum GmbH, Planckstr. 1, D-64291 Darmstadt (Germany)

2010-03-15T23:59:59.000Z

307

Conversion of second class constraints by deformation of Lagrangian local symmetries  

E-Print Network (OSTI)

For a theory with first and second class constraints, we propose a procedure for conversion of second class constraints based on deformation the structure of local symmetries of the Lagrangian formulation. It does not require extension or reduction of configuration space of the theory. We give examples in which the initial formulation implies a non linear realization of some global symmetries, therefore is not convenient. The conversion reveals hidden symmetry presented in the theory. The extra gauge freedom of conversed version is used to search for a parameterization which linearizes the equations of motion. We apply the above procedure to membrane theory (in the formulation with world-volume metric). In the resulting version, all the metric components are gauge degrees of freedom. The above procedure works also in a theory with only second class constraints presented. As an examples, we discuss arbitrary dynamical system of classical mechanics subject to kinematic constraints, O(N)-invariant nonlinear sigma-model, and the theory of massive vector field with Maxwell-Proca Lagrangian.

A. A. Deriglazov; Z. Kuznetsova

2006-10-07T23:59:59.000Z

308

Three-dimensional metrics as deformations of a constant curvature metric  

E-Print Network (OSTI)

Any three-dimensional Riemannian metric can be locally obtained by deforming a constant curvature metric along one direction. The general interest of this result, both in geometry and physics, and related open problems are stressed.

B. Coll; J. Llosa; D. Soler

2001-04-23T23:59:59.000Z

309

Frontal Wave Stability during Moist Deformation Frontogenesis. Part I: Linear Wave Dynamics  

Science Conference Proceedings (OSTI)

It has been shown that lower tropospheric potential vorticity zones formed during moist deformation frontogenesis will support growing waves if at some time the frontogenesis ceases. In this paper, the ways in which these waves are affected by ...

Craig H. Bishop; Alan J. Thorpe

1994-03-01T23:59:59.000Z

310

Frontal Wave Stability during Moist Deformation Frontogenesis. Part II: The Suppression of Nonlinear Wave Development  

Science Conference Proceedings (OSTI)

In this paper, the role of horizontal deformation and the associated frontogenetic ageostrophic circulation in suppressing the development of nonlinear waves is assessed. Unless linear barotropic frontal waves can become nonlinear, the associated ...

Craig H. Bishop; Alan J. Thorpe

1994-03-01T23:59:59.000Z

311

A microfabricated deformability-based flow cytometer with application to malaria  

E-Print Network (OSTI)

Malaria resulting from Plasmodium falciparum infection is a major cause of human suffering and mortality. Red blood cell (RBC) deformability plays a major role in the pathogenesis of malaria. Here we introduce an automated ...

Bow, Hansen

312

Black Holes, q-Deformed 2d Yang-Mills, and Non-perturbative Topological Strings  

E-Print Network (OSTI)

Two-dimensional Yang-Mills, black holes and topologicalfor the two- dimensional black hole,ö Nucl. Phys. B 622 (LBNL- 56688 Black Holes, q-Deformed 2d Yang-Mills, and Non-

Aganagic, Mina

2009-01-01T23:59:59.000Z

313

The Effect of Hydrogen on the Deformation and Fracture of PWA 1480  

Science Conference Proceedings (OSTI)

THE EFFECT OF HYDROGEN ON THE DEFORMATION AND. FRACTURE OF PWA 1480. W.S. Walston, N.R. Moody*, M. Dollar*, I.M. Bernstein* and J.C.á...

314

Method of deforming a biaxially textured buffer layer on a textured metallic substrate and articles therefrom  

DOE Patents (OSTI)

The present invention provides methods and biaxially textured articles having a deformed epitaxial layer formed therefrom for use with high temperature superconductors, photovoltaic, ferroelectric, or optical devices. A buffer layer is epitaxially deposited onto biaxially-textured substrates and then mechanically deformed. The deformation process minimizes or eliminates grooves, or other irregularities, formed on the buffer layer while maintaining the biaxial texture of the buffer layer. Advantageously, the biaxial texture of the buffer layer is not altered during subsequent heat treatments of the deformed buffer. The present invention provides mechanical densification procedures which can be incorporated into the processing of superconducting films through the powder deposit or precursor approaches without incurring unfavorable high-angle grain boundaries.

Lee, Dominic F. (Knoxville, TN); Kroeger, Donald M. (Knoxville, TN); Goyal, Amit (Knoxville, TN)

2000-01-01T23:59:59.000Z

315

The Hot Deformation Behavior of an As-Cast Alloy 718 Ingot  

Science Conference Proceedings (OSTI)

The data suggest that hot working in the temperature range of .... 12.5% distilled water, 10% ... The stress-strain curves for samples deformed at 950░C exhibited.

316

Topics in Noncommutative Gauge Theories and Deformed Relativistic Theories  

E-Print Network (OSTI)

This is my PhD thesis. In this thesis we study the gauge theories on noncommutative Moyal space. We find new static solitons and instantons in terms of the so called generalized Bose operators. Generalized Bose operators are constructed to describe reducible representation of the oscillator algebra. They create/annihilate $k$-quanta, $k$ being a positive integer. We start with giving an alternative description to the already found static magnetic flux tube solutions of the noncommutative gauge theories in terms of generalized Bose operators. The Nielsen-Olesen vortex solutions found in terms of these operators reduce to the already found ones. On the contrary we find a class of new instaton solutions which are unitarily inequivalant to the the ones found from ADHM construction on noncommutative space. The charge of the instaton has a description in terms of the index representing the reducibility of the Fock space, i.e., $k$. After studying the static solitonic solutions in noncommutative Minkowski space and the instaton solutions in noncommutative Euclidean space we go on to study the implications of the time-space noncommutativity in Minkowski space. To understand it properly we study the time-dependent transitions of a forced harmonic oscillator in noncommutative 1+1 dimensional spacetime. We also try to understand the implications of the found results in the context of quantum optics. We then shift to the so called DSR theories which are related to a different kind of noncommutative ($\\kappa$-Minkowski) space. DSR (Doubly/Deformed Special Relativity) aims to search for an alternate relativistic theory which keeps a length/energy scale (the Planck scale) and a velocity scale (the speed of light scale) invariant. We study thermodynamics of an ideal gas in such a scenario.

Nitin Chandra

2013-01-17T23:59:59.000Z

317

$?(\\hat{x},\\hat{p})-$deformation of the harmonic oscillator in a $2D-$phase space  

E-Print Network (OSTI)

This work addresses a ${\\theta}(\\hat{x},\\hat{p})-$deformation of the harmonic oscillator in a $2D-$phase space. Specifically, it concerns a quantum mechanics of the harmonic oscillator based on a noncanonical commutation relation depending on the phase space coordinates. A reformulation of this deformation is considered in terms of a $q-$deformation allowing to easily deduce the energy spectrum of the induced deformed harmonic oscillator. Then, it is proved that the deformed position and momentum operators admit a one-parameter family of self-adjoint extensions. These operators engender new families of deformed Hermite polynomials generalizing usual $q-$ Hermite polynomials. Relevant matrix elements are computed. Finally, a $su(2)-$algebra representation of the considered deformation is investigated and discussed.

M. N. Hounkonnou; D. Ousmane Samary; E. Baloitcha; S. Arjika

2012-11-01T23:59:59.000Z

318

Continuous Severe Plastic Deformation Processing of Aluminum Alloys  

SciTech Connect

Metals with grain sizes smaller than 1-micrometer have received much attention in the past decade. These materials have been classified as ultra fine grain (UFG) materials (grain sizes in the range of 100 to 1000-nm) and nano-materials (grain size <100-nm) depending on the grain size. This report addresses the production of bulk UFG metals through the use of severe plastic deformation processing, and their subsequent use as stock material for further thermomechanical processing, such as forging. A number of severe plastic deformation (SPD) methods for producing bulk UFG metals have been developed since the early 1990s. The most promising of these processes for producing large size stock that is suitable for forging is the equal channel angular extrusion or pressing (ECAE/P) process. This process involves introducing large shear strain in the work-piece by pushing it through a die that consists of two channels with the same cross-sectional shape that meet at an angle to each other. Since the cross-sections of the two channels are the same, the extruded product can be re-inserted into the entrance channel and pushed again through the die. Repeated extrusion through the ECAE/P die accumulates sufficient strain to breakdown the microstructure and produce ultra fine grain size. It is well known that metals with very fine grain sizes (< 10-micrometer) have higher strain rate sensitivity and greater elongation to failure at elevated temperature, exhibiting superplastic behavior. However, this superplastic behavior is usually manifest at high temperature (> half the melting temperature on the absolute scale) and very low strain rates (< 0.0001/s). UFG metals have been shown to exhibit superplastic characteristics at lower temperature and higher strain rates, making this phenomenon more practical for manufacturing. This enables part unitization and forging more complex and net shape parts. Laboratory studies have shown that this is particularly true for UFG metals produced by SPD techniques. This combination of properties makes UFG metals produced by SPD very attractive as machining, forging or extrusion stock, both from the point of view of formability as well as energy and cost saving. However, prior to this work there had been no attempt to transfer these potential benefits observed in the laboratory scale to industrial shop floor. The primary reason for this was that the laboratory scale studies had been conducted to develop a scientific understanding of the processes that result in grain refinement during SPD. Samples that had been prepared in the laboratory scale were typically only about 10-mm diameter and 50-mm long (about 0.5-inch diameter and 2-inches long). The thrust of this project was three-fold: (i) to show that the ECAE/P process can be scaled up to produce long samples, i.e., a continuous severe plastic deformation (CSPD) process, (ii) show the process can be scaled up to produce large cross section samples that could be used as forging stock, and (iii) use the large cross-section samples to produce industrial size forgings and demonstrate the potential energy and cost savings that can be realized if SPD processed stock is adopted by the forging industry. Aluminum alloy AA-6061 was chosen to demonstrate the feasibility of the approach used. The CSPD process developed using the principles of chamber-less extrusion and drawing, and was demonstrated using rolling and wire drawing equipment that was available at Oak Ridge National Laboratory. In a parallel effort, ECAE/P dies were developed for producing 100-mm square cross section SPD billets for subsequent forging. This work was carried out at Intercontinental Manufacturing Co. (IMCO), Garland TX. Forging studies conducted with the ECAE/P billets showed that many of the potential benefits of using UFG material can be realized. In particular, the material yield can be increased, and the amount of material that is lost as scrap can be reduced by as much as 50%. Forging temperatures can also be reduced by over 150║C, resulting in energy savings in the ope

Raghavan Srinivasan (PI); Prabir K. Chaudhury; Balakrishna Cherukuri; Qingyou Han; David Swenson; Percy Gros

2006-06-30T23:59:59.000Z

319

The research program of Stochastic Deformation (with a view toward Geometric Mechanics)  

E-Print Network (OSTI)

This is an overview of a program of stochastic deformation of the mathematical tools of classical mechanics, in the Lagrangian and Hamiltonian approaches. It can also be regarded as a stochastic version of Geometric Mechanics.The main idea is to construct well defined probability measures strongly inspired by Feynman Path integral method in Quantum Mechanics. In contrast with other approaches, this deformation preserves the invariance under time reversal of the underlying classical (conservative) dynamical systems.

Jean-Claude Zambrini

2012-12-17T23:59:59.000Z

320

The uses of the refined matrix model recursion  

Science Conference Proceedings (OSTI)

We study matrix models in the {beta}-ensemble by building on the refined recursion relation proposed by Chekhov and Eynard. We present explicit results for the first {beta}-deformed corrections in the one-cut and the two-cut cases, as well as two applications to supersymmetric gauge theories: the calculation of superpotentials in N=1 gauge theories, and the calculation of vevs of surface operators in superconformal N=2 theories and their Liouville duals. Finally, we study the {beta}-deformation of the Chern-Simons matrix model. Our results indicate that this model does not provide an appropriate description of the {Omega}-deformed topological string on the resolved conifold, and therefore that the {beta}-deformation might provide a different generalization of topological string theory in toric Calabi-Yau backgrounds.

Brini, Andrea; Marino, Marcos; Stevan, Sebastien [Departement de Physique Theorique et Section de Mathematiques, Universite de Geneve, Geneve CH-1211 (Switzerland)

2011-05-15T23:59:59.000Z

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


321

Electric-magnetic duality and deformations of three-dimensional conformal field theories  

SciTech Connect

SL(2,Z) duality transformations in asymptotically AdS{sub 4}xS{sup 7} act nontrivially on the three-dimensional superconformal field theory of coincident M2-branes on the boundary. We show how S-duality acts away from the IR fixed point. We develop a systematic method to holographically obtain the deformations of the boundary CFT and show how electric-magnetic duality relates different deformations. We analyze in detail marginal deformations and deformations by dimension 4 operators. In the case of massive deformations, the renormalization group flow relates S-dual CFT's. Correlation functions in the CFT are computed by varying magnetic bulk sources, whereas correlation functions in the dual CFT are computed by electric bulk sources. Under massive deformations, the boundary effective action is generically minimized by massive self-dual configurations of the U(1) gauge field. We show that a self-dual choice of boundary conditions exists, and it corresponds to the self-dual topologically massive gauge theory in 2+1 dimensions. Thus, self-duality in three dimensions can be understood as a consequence of electric-magnetic invariance in the bulk of AdS{sub 4}.

Haro, Sebastian de [Department of Mathematics, King's College, London WC2R 2LS (United Kingdom); Gao Peng [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396 (United States)

2007-11-15T23:59:59.000Z

322

Deformation and Fracture of an Alpha/Beta Titanium Alloy  

Science Conference Proceedings (OSTI)

Overview of Microstructural Models Applied to Hot Rolling Mill for Long ... Study of Composite Materials Application for Horizontal Axis Wind Turbine Blades.

323

Material Deformation Dynamics at Ultrahigh Pressures and Strain ...  

Science Conference Proceedings (OSTI)

Study of Composite Materials Application for Horizontal Axis Wind Turbine Blades ... Using the Computational Modelling to Improve Durability of Diesel Engineá...

324

Predicting Deformation of Single Crystal Niobium Using Crystal ...  

Science Conference Proceedings (OSTI)

... Nb. Crystal plasticity models capable of predicting shape changes in single crystal Nb dog bone samples having different orientations have been developed, á...

325

Grain Boundary Deformation Analyzed Via X-Ray Diffraction ...  

Science Conference Proceedings (OSTI)

Modeling the Influence of the Second Phase Particle Spatial Distribution on Recrystallization of AA 7050 Ě Near-Field High Energy X-ray Diffraction Microscopyá...

326

Modeling and simulation of film blowing process  

E-Print Network (OSTI)

Film blowing process is a flexible mass production technology used for manufacturing thin polymeric films. Its flexibility in using an existing die to produce films of different width and thickness, just by controlling process conditions such as, extrudate velocity, excess pressure, and line speed, makes it an attractive process with less capital investment. Controlling the process conditions to obtain a stable bubble, however, is not a trivial task. It is a costly trial and error procedure, which could result is a large wastage of material and other resources. Hence, it is necessary to develop methods to simulate the process and design it using numerical experiments. This important need of the industry defines the objective of this work. In this dissertation, a transient, axisymmetric, nonisothermal, viscoelastic model is developed to simulate the process, and it is solved using finite element method. Material behavior of polymer melt is described using a modified Phan-Thien-Tanner model in the liquid??like region, and anisotropic Kelvin??Voight model in the solid zone, and the transition is modeled using a simple mixture theory. Crystallization kinetics is described using a modified Avrami model with factors to account for the influence of temperature and strain. Results obtained are compared with available experimental results and the model is used to explore stability issues and the role of different parameters. Software developed using this model comes with a GUI based pre- and post-processor, and it can be easily adapted to use other constitutive models.

Mayavaram, Ravisankar S.

2006-05-01T23:59:59.000Z

327

Modeling Linear Kinematic Features in Sea Ice  

Science Conference Proceedings (OSTI)

Sea ice deformation is localized in narrow zones of high strain rate that extend hundreds of kilometers, for example, across the Arctic Basin. This paper demonstrates that these failure zones may be modeled with a viscousľplastic sea ice model, ...

Jennifer K. Hutchings; Petra Heil; William D. Hibler III

2005-12-01T23:59:59.000Z

328

Simple data-driven modeling of brushes  

Science Conference Proceedings (OSTI)

We present a new and simple data-driven technique for modeling 3D brushes for use in realistic painting programs. Our technique simplifies and accelerates simulation of the constrained dynamics of brushes by using a small lookup table that efficiently ... Keywords: data-driven, deformation, dynamics, example-based, optimization, painting systems, physically based modeling

William Baxter; Naga Govindaraju

2010-02-01T23:59:59.000Z

329

Fabrication of amorphous metal matrix composites by severe plastic deformation  

E-Print Network (OSTI)

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 by equal channel angular extrusion (ECAE) for consolidation of bulk amorphous metals (BAM) and amorphous metal matrix composites (AMMC) is investigated in this dissertation. The objectives of this research are a) to better understand processing parameters which promote bonding between particles and b) to determine by what mechanisms the plasticity is enhanced in bulk amorphous metal matrix composites consolidated by ECAE. To accomplish the objectives BAM and AMMCs were produced via ECAE consolidation of Vitreloy 106a (Zr58.5Nb2.8Cu15.6Ni12.8Al10.3-wt%), ARLloy #1 (Hf71.3Cu16.2Ni7.6Ti2.2Al2.6 -wt%), and both of these amorphous alloys blended with crystalline phases of W, Cu and Ni. Novel instrumented extrusions and a host of postprocessing material characterizations were used to evaluate processing conditions and material properties. The results show that ECAE consolidation at temperatures within the supercooled liquid region gives near fully dense (>99%) and well bonded millimeter scale BAM and AMMCs. The mechanical properties of the ECAE processed BMG are comparable to cast material: ├Ć┬?f = 1640 MPa, ├?┬Áf = 2.3%, E = 80 GPa for consolidated Vitreloy 106a as compared to ├Ć┬?f = 1800 MPa, ├?┬Áf = 2.5%, E = 85 GPa for cast Vitreloy 106, and ├Ć┬?f = 1660 MPa, ├?┬Áf = 2.0%, E = 97 GPa for ARLloy #1 as compared to ├Ć┬?f = 2150 MPa, ├?┬Áf oxides and crystalline phase morphology and chemistry. It is demonstrated that the addition of a dispersed crystalline phase to an amorphous matrix by ECAE powder consolidation increases the plasticity of the amorphous matrix by providing locations for generation and/or arrest of adiabatic shear bands. The ability of ECAE to consolidated BAM and AMMCs with improved plasticity opens the possibility of overcoming the size and plasticity limitations of the monolithic bulk metallic glasses.

Mathaudhu, Suveen Nigel

2006-08-01T23:59:59.000Z

330

LITERATURE SURVEY ON CEMENTS FOR REMEDIATION OF DEFORMED CASING IN GEOTHERMAL WELLS  

DOE Green Energy (OSTI)

Brookhaven National Laboratory was requested to conduct a literature survey for the best available cement to use in the proposed casing patch as part of the Geothermal Drilling Organization (GDO) project on remediation of deformed casings. A total of 50 wells has been identified with deformed production casing in Unocal's portion of The Geysers geothermal field. Reduced internal diameter and casing doglegs result in lost production and the possible need for abandonment. The cause of the deformations is believed to be formation movement along fault planes and/or along weaker layers or interfaces between high impedance contrast media. Apparently, it is unclear whether shear or axial compression is the dominant failure mechanism. A procedure to address the casing deformation and avoid abandonment of these wells has been developed as described in the Geysers Deformed Casing Remediation Proposal. The proposed remediation procedure involves isolation of the zone of interest with an inflatable packer, milling the deformed casing and cementing a 7 inch diameter liner to extend approximately 100 ft above and 100 ft below the milled zone. During the milling operation it is possible that the original cement and surrounding formation may slough away. In order to specify a suitable cement formulation for the casing patch it is first necessary to identify and understand the deformation mechanism/s operating in The Geysers field. Subsequently, the required cement mechanical properties to withstand further deformation of the repaired system must be defined. From this information it can be determined whether available cement formulations meet these requirements. In addition to The Geysers, other geothermal fields are at possible risk of casing deformation due to subsidence, seismic activity, lateral and vertical formation movement or other processes. Therefore, the proposed remediation procedure may have applications in other fields. The literature survey focused on published properties for cements used in geothermal and oil well applications and the experiences of well casing deformation occurring in oil and gas fields. Dr. Mike Bruno of Terralog Technologies kindly supplied a reference list from the DEA (Drilling Engineering Association) 99 Project on Analysis of Well Casing Damage Induced by Reservoir Compaction and Overburden Shear.

ALLAN,M.L.; PHILIPPACOPOULOS,A.J.

1998-11-01T23:59:59.000Z

331

Progress in sub-grid scale modeling of shock-turbulence interaction  

DOE Green Energy (OSTI)

The authors report on progress in the development of sub grid scale (SGS) closure relationships for the unresolved motion scales in compressible large eddy simulations (LES). At present they are refining the SGS model and overall LES procedure to include: a linearized viscoelastic model for finite thickness shock distortions and shocked turbulence field response; multiple scale asymptotic considerations to improve predictions of average near-wall surface behavior; and a spectral statistical model simulating the effects of high wave number stochastic feed-back from the unresolved SGS nonlinear motion influences on the explicitly resolved grid scale motions. Predicted amplification levels, modal energy partition, shock translational to turbulence kinetic energy transfer, and viscoelastic spatio-temporal response of turbulence to shock interaction are examined in comparison with available experimental evidence. Supplemental hypersonic compressible turbulence experimental information is developed from sub nanosecond interval pulsed shadowgraph evidence of laser impulse generated hypervelocity shocks interacting with intense, previously developed and carefully characterized initial turbulence. Accurate description of the influence of shock-turbulence interactions is vital for predicting their influence on: Supersonic/hypersonic flow field analysis, aerodynamic design, and aerostructural materials selection. Practical applications also include interior supersonic combustion analysis and combustion chamber design. It is also the essential foundation for accurately predicting the development and evolution of flow-field generated thermal and electromagnetic radiation important to hypersonic flight vehicle survivability, detection and communication.

Buckingham, A.C. [Lawrence Livermore National Lab., CA (United States). Center for Advanced Fluid Dynamics Applications; Grun, J. [Naval Research Lab., Washington, DC (United States). Plasma Physics Div.

1994-12-01T23:59:59.000Z

332

Precipitation Behaviour in Severe Plastic Deformed Beta-type ...  

Science Conference Proceedings (OSTI)

Composition Design of Multi-Component ?-Ti Alloys Based on a Cluster Model Ě Consolidation of Blended Titanium/Magnesium Powders by Microwave Processing ... Rheological Properties of Feedstock Composed of Titanium Alloy Powderá...

333

Using GPS to Rapidly Detect and Model Earthquakes and Transient Deformation Events /  

E-Print Network (OSTI)

Scaling 2.7.4 Timeline of Event Analysis from Seismogeodetic2013b]. Timeline of Event Analysis from Seismogeodetic Dataanalysis. In recent years, the discovery of slow slip events

Crowell, Brendan William

2013-01-01T23:59:59.000Z

334

A Deformable Model for Bringing Particles in Anders Lindbjerg Dahl1  

E-Print Network (OSTI)

in for example a fermentation process, oil droplets in water, coal particles in a power plant, and spray the particle size. This can be handled by only including the particles in focus, but most of the depicted all particles in focus. Therefore we need to handle the out-of-focus blur, but this also provide

Dahl, Anders Lindbjerg

335

High Temperature Deformation Behavior and Modeling of Al/SiC ...  

Science Conference Proceedings (OSTI)

The nanolaminates were processed by physical vapor deposition (PVD) using ... by high temperature nanoindentation and pillar creep compression at 100, 200,á...

336

Using GPS to Rapidly Detect and Model Earthquakes and Transient Deformation Events /  

E-Print Network (OSTI)

and P. Shanker (2007), Subsidence monitoring in Imperialof extension, shear and subsidence in the Salton Trough, oneal. , 2009]. Large scale subsidence and anomalous heat flow

Crowell, Brendan William

2013-01-01T23:59:59.000Z

337

LV Motion and Strain Computation from tMRI based on Meshless Deformable Models  

E-Print Network (OSTI)

, 2007, pp. 469┬ş476. 11. T. Chen, S. Chung, and L. Axel, "Automated tag tracking using gabor filter bank

338

Meshless Deformable Models for LV Motion Analysis Xiaoxu Wang Dimitis Metaxas  

E-Print Network (OSTI)

-Assisted Intervention, pages 469┬ş476, 2007. 6 [3] T. Chen, S. Chung, and L. Axel. Automated tag tracking us- ing gabor

339

Studies of co- and postseismic deformation of the lithosphere from numerical models and space geodetic data  

E-Print Network (OSTI)

TRANSITION MATRIX DIFFUSIVITY VELOCITY STRENGTHENING PORE PRESSURE COUPLING DEPTH RATE - AND - STATE FRICTION POWER -

Barbot, Sylvain

2009-01-01T23:59:59.000Z

340

Modeling the deformation and failure behavior of FCC and HCP nanocrystalline materials  

E-Print Network (OSTI)

As foreseen by Richard Feynman in his famous talk titled There's Plenty of Room at the Bottom in 1959, scientists nowadays are miniaturizing structures in materials to achieve better performance as concerned in technical ...

Wei, Yujie, Ph. D. Massachusetts Institute of Technology

2006-01-01T23:59:59.000Z

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


341

PROPERTIES AND NANOSTRUCTURES OF NANO-MATERIALS PROCESSED BY SEVERE PLASTIC DEFORMATION (SPD).  

Science Conference Proceedings (OSTI)

Metallic materials usually exhibit higher strength but lower ductility after being plastically deformed by conventional techniques such as rolling, drawing and extrusion. In contrast, nanostructured metals and alloys processed by severe plastic deformation (SPD) have demonstrated both high strength and high ductility. This extraordinary mechanical behavior is attributed to the unique nanostructures generated by SPD processing. The combination of ultrafine grain size and high-density dislocations appears to enable deformation by new mechanisms not active in coarse-grained metals and alloys. These results demonstrate the possibility of tailoring the microstructures of metals and alloys by SPD to obtain superior mechanical properties. Nanostructured metals and alloys processed by SPD techniques have unique nanostructures not observed in nanomaterials synthesized by other techniques such as the consolidation of nanopowders. The SPD-generated nanostructures have many features related to deformation, including high dislocation densities, and high- and low-angle grain boundaries in equilibrium or nonequilibrium states. Future studies are needed to investigate the deformation mechanisms that relate the unique nanostructures with the superior mechanical properties exhibited by SPD-processed metals and alloys.

Zhu, Y. T. (Yuntian Theodore)

2001-01-01T23:59:59.000Z

342

The deformations of flat affine structures on the two-torus  

E-Print Network (OSTI)

The group action which defines the moduli problem for the deformation space of flat affine structures on the two-torus is the action of the affine group $\\Aff(2)$ on $\\bbR^2$. Since this action has non-compact stabiliser $\\GL(2,\\bbR)$, the underlying locally homogeneous geometry is highly non-Riemannian. In this article, we describe the deformation space of all flat affine structures on the two-torus. In this context interesting phenomena arise in the topology of the deformation space, which, for example, is \\emph{not} a Hausdorff space. This contrasts with the case of constant curvature metrics, or conformal structures on surfaces, which are encountered in classical Teichm\\"uller theory. As our main result on the space of deformations of flat affine structures on the two-torus we prove that the holonomy map from the deformation space to the variety of conjugacy classes of homomorphisms from the fundamental group of the two-torus to the affine group is a local homeomorphism.

Baues, Oliver

2011-01-01T23:59:59.000Z

343

Mechanical deformation of neutrophil into pulmonary capillaries induces cytoskeletal remodeling, pseudopod projection and changes in biomechanical properties  

E-Print Network (OSTI)

Neutrophils traversing the pulmonary microcirculation are subjected to mechanical stimulation during their deformation into narrow capillaries. To better understand the time- dependant changes caused by this mechanical ...

Yap, Belinda

2005-01-01T23:59:59.000Z

344

Effect of regimes of hot plastic deformation on the structure and properties of stamped billets  

SciTech Connect

One way of increasing the service life and reliability of gas-turbine engines is to raise the endurance limit of compressor blades by improving the manufacturing technology. The endurance limit of the blades depends on many factors, the most important of which is the structural state of the material for blade billets. A stable, high endurance limit can be attained if the whole complex of technological effects, beginning with the hot deformation and ending with the surface treatment of ready parts, is optimized. The regimes of hot deformation which creates the initial structure mainly determines the endurance limit. In this paper the influence of the regimes of hot deformation on the structure and endurance limit of stamped billets imitating compressor blades is investigated for KhN45MVTYuBR-ID (EP718-ID) alloy.

Maslenkov, S.B.; Larkin, V.A.; Zhebyneva, N.F. [Scientific-Research Inst. of Engines, Moscow (Russian Federation)

1995-07-01T23:59:59.000Z

345

Deformation Microstructures of 30 dpa AISI 304 Stainless Steel after ...  

Science Conference Proceedings (OSTI)

Previously the results of slow strain rate tensile and constant load autoclave tests ... Detailed Root Cause Analysis of SG Tube ODSCC Indications within the Tube Sheets of NPP Biblis Unit A .... Radiation Damage in Fe-C-Met Model Alloys ... Stress Corrosion Cracking Behavior near the Fusion Boundary of Dissimilar Weld

346

Large deformation diffeomorphisms with application to optic flow  

Science Conference Proceedings (OSTI)

Using standard statistical assumptions we derive a stochastic differential equation generating flows of diffeomorphisms. These stochastic processes provide a generative model for non-rigid registration and image warping problems. We give a mathematically ... Keywords: Image warping, Landmark matching, Maximum a posteriori estimation, Non-rigid registration, Optic flow, Renormalized Brownian density, Stochastic differential equations

Bo Markussen

2007-04-01T23:59:59.000Z

347

Coupling water and smoke to thin deformable and rigid shells  

Science Conference Proceedings (OSTI)

We present a novel method for solid/fluid coupling that can treat infinitesimally thin solids modeled by a lower dimensional triangulated surface. Since classical solid/fluid coupling algorithms rasterize the solid body onto the fluid grid, an entirely ... Keywords: cloth, rigid bodies, shells, smoke, water

Eran Guendelman; Andrew Selle; Frank Losasso; Ronald Fedkiw

2005-07-01T23:59:59.000Z

348

Method for measuring residual stresses in materials by plastically deforming the material and interference pattern comparison  

DOE Patents (OSTI)

A method for measuring residual stress in a material comprising the steps of establishing a speckle pattern on the surface with a first laser then heating a portion of that pattern with an infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress dung heating and enables calculation of the stress.

Pechersky, Martin J. (241 Chardonnat La., Aiken, SC 29803)

1995-01-01T23:59:59.000Z

349

Modelling and simulation of acrylic bone cement injection and curing within the framework of vertebroplasty  

E-Print Network (OSTI)

The minimal invasive procedure of vertebroplasty is a surgical technique to treat compression fractures of vertebral bodies. During the treatment liquid bone cement gets injected into the affected vertebral body and therein cures to a solid. In order to investigate the treatment and the impact of injected bone cement on the vertebra, an integrated modelling and simulation framework has been developed. The framework includes (i) the generation of computer models based on microCT images of human cancellous bone, (ii) CFD simulations of bone cement injection into the trabecular structure of a vertebral body as well as (iii) non-linear FEM simulations of the bone cement curing. Thereby, microstructural models of trabecular bone structures are employed. Furthermore, a detailed description of the material behaviour of acrylic bone cements is provided. More precisely, a non-linear fluid flow model is chosen for the representation of the bone cement behaviour during injection and a non-linear viscoelastic material mo...

Landgraf, Ralf; Kolmeder, Sebastian; Lion, Alexander; Lebsack, Helena; Kober, Cornelia

2013-01-01T23:59:59.000Z

350

Internal Frontogenesis: A Two-Dimensional Model in Isentropic, Semi-Geostrophic Coordinates  

Science Conference Proceedings (OSTI)

A two-dimensional semi-geostrophic model in isentropic coordinates is applied to the study of internal frontogenesis induced by a geostrophic deformation field. A continuous potential vorticity distribution is considered and the upper and lower ...

Andrea Buzzi; Anna Trevisan; Giovanna Salustri

1981-05-01T23:59:59.000Z

351

Multimechanism-Deformation Parameters of Domal Salts Using Transient Creep Analysis  

SciTech Connect

Use of Gulf Coast salt domes for construction of very large storage caverns by solution mining has grown significantly in the last several decades. In fact, among the largest developers of storage caverns along the Gulf Coast is the Strategic Petroleum Reserve (SPR) which has purchased or constructed 62 crude oil storage caverns in four storage sites (domes). Although SPR and commercial caverns have been operated economically for many years, the caverns still exhibit some relatively poorly understood behaviors, especially involving creep closure volume loss and hanging string damage from salt falls. Since it is possible to postulate that some of these behaviors stem from geomechanical or reformational aspects of the salt, a method of correlating the cavern response to mechanical creep behavior as determined in the laboratory could be of considerable value. Recently, detailed study of the creep response of domal salts has cast some insight into the influence of different salt origins on cavern behavior. The study used a simple graphical analysis of limited non-steady state data to establish an approach or bound to steady state, as an estimate of the steady state behavior of a given salt. This permitted analysis of sparse creep databases for domal salts. It appears that a shortcoming of this steady state analysis method is that it obscures some critical differences of the salt material behavior. In an attempt to overcome the steady state analysis shortcomings, a method was developed based on integration of the Multimechanism-Deformation (M-D) creep constitutive model to obtain fits to the transient response. This integration process permits definition of all the material sensitive parameters of the model, while those parameters that are constants or material insensitive parameters are fixed independently. The transient analysis method has proven more sensitive to differences in the creep characteristics and has provided a way of defining different behaviors within a given dome. Characteristics defined by the transient analysis are related quantitatively to the volume loss creep rate of the SPR caverns. This increase in understanding of the domal material creep response already has pointed to the possibility y of delineating the existence of material spines within a specific dome. Further definition of the domal geology and structure seems possible only through expansion of the creep databases for domal salts.

MUNSON, DARRELL E

1999-09-01T23:59:59.000Z

352

Effect of twinning on texture evolution of depleted uranium using a viscoplastic self-consistent model  

Science Conference Proceedings (OSTI)

Ductility and fracture toughness is a major stumbling block in using depleted uranium as a structural material. The ability to correctly model deformation of uranium can be used to create process path methods to improve its structural design ability. The textural evolution of depleted uranium was simulated using a visco-plastic self consistent model and analyzed by comparing pole figures of the simulations and experimental samples. Depleted uranium has the same structure as alpha uranium, which is an orthorhombic phase of uranium. Both deformation slip and twin systems were compared. The VPSC model was chosen to simulate this material because the model encompasses both low-symmetry materials as well as twinning in materials. This is of particular interest since depleted uranium has a high propensity for twinning, which dominates deformation and texture evolution. Simulated results were compared to experimental results to measure the validity of the model. One specific twin system, the {l_brace}176{r_brace}[512] twin, was of specific notice. The VPSC model was used to simulate the influence of this twin on depleted uranium and was compared with a mechanically shocked depleted uranium sample. Under high strain rate shock deformation conditions, the {l_brace}176{r_brace}[512] twin system appears to be a dominant deformation system. By simulating a compression process using the VPSC model with the {l_brace}176{r_brace}[512] twin as the dominant deformation mode, a favorable comparison could be made between the experimental and simulated textures. (authors)

Ho, J.; Garmestani, H. [Georgia Inst. of Technology, Atlanta, GA 30332-0245 (United States); Burrell, R.; Belvin, A. [Y-12 National Security Complex, Oak Ridge, TN (United States); Li, D. [Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); McDowell, D. [Woodruff School of Mechanical Engineering, Atlanta, GA 30332-0245 (United States); Rollett, A. [Dept. of Materials Science and Engineering, Carnegie Mellon Univ., Pittsburgh, PA 15213 (United States)

2012-07-01T23:59:59.000Z

353

q-alg/9704018 Note on the Algebra of Screening Currents for the Quantum Deformed W-Algebra  

E-Print Network (OSTI)

With slight modifications in the zero modes contributions, the positive and negative screening currents for the quantum deformed W-algebraWq,p(g) can be put together to form a single algebra which can be regarded as an elliptic deformation of the universal enveloping algebra of ?g, where g is any classical simply-laced Lie algebra. Recently, various deformations of the classical and quantum Virasoro and W-algebras have received considerable interests. N.Reshetikhin and E.Frenkel [4] first introduced the Poisson algebras Wq(g), which are q-deformation of classical W-algebras. Later on, J.Shiraishi, H.Kubo, H.Awata and S.Odake [11] obtained a quantum version of the algebra Wq(sl2), which is a noncommutative algebra depending on two parameters p and q. B.Feigin and E.Frenkel [2] extended this result to general case, i.e. quantum deformed W-algebras Wq,p(g), where g is any classical semisimple Lie algebra. All these algebras were obtained together with their respective bosonic Fock space representations. Similar considerations with respect to the Yangian deformation were also carried out and have led to »h deformed Virasoro algebra [1] and quantum (?, »h)-deformed W-algebras [6].

Liu Zhao; Bo-yu Hou

1997-01-01T23:59:59.000Z

354

Pleistocene hinterland evolution of the active Banda Arc: Surface uplift and neotectonic deformation recorded by coral terraces at Kisar, Indonesia  

E-Print Network (OSTI)

deformation recorded by coral terraces at Kisar, Indonesia AND Hinterland emergence of the active Banda arc-continent collision: Metamorphism, geochronology, and structure of the uplifted Kisar Atoll, Indonesia and related Banda Arc: surface uplift and neotectonic deformation recorded by coral terraces at Kisar, Indonesia

Seamons, Kent E.

355

Mesh-free simulations of shear banding in large deformation Shaofan Li, Wei Hao, Wing Kam Liu *  

E-Print Network (OSTI)

Mesh-free simulations of shear banding in large deformation Shaofan Li, Wei Hao, Wing Kam Liu Mesh-free approximation is used in numerical simulations of strain localization under large deformation. An explicit displacement based mesh-free formulation is used in both two-dimensional and three

Li, Shaofan

356

Multiple-humped fission and fusion barriers of the heaviest elements and ellipsoidal deformations  

E-Print Network (OSTI)

leading possibly to superheavy elements, double-humped potential barriers appear for cold fusionMultiple-humped fission and fusion barriers of the heaviest elements and ellipsoidal deformations G barriers and the predicted half-lives of actinides follow the experimental results. In the fusion path

Paris-Sud XI, Universit├ę de

357

Correlation of microseismic and chemical properties of brittle deformation in Locharbriggs sandstone  

E-Print Network (OSTI)

: stress corrosion, acoustic emission, silica dissolution, subcritical crack growth, deformation rate of the strained crack tip bonds may facilitate crack propaga- tion. This mechanism is known as stress corrosion. In fact, subcritical crack growth by stress corrosion or dissolution is probably the dominant mechanism

358

REACTIVE FLOW IN LARGE-DEFORMATION ELECTRODES OF LITHIUM-ION BATTERIES  

E-Print Network (OSTI)

8/3/2012 1 REACTIVE FLOW IN LARGE-DEFORMATION ELECTRODES OF LITHIUM-ION BATTERIES LAURENCE BRASSART;8/3/2012 2 1. Introduction In a lithium-ion battery, each electrode is a host of lithium. When the battery to 4.4 lithium atoms. By comparison, in the commonly used anodes in lithium-ion batteries made

Suo, Zhigang

359

Large Plastic Deformation in High-Capacity Lithium-Ion Batteries Caused by Charge and Discharge  

E-Print Network (OSTI)

Large Plastic Deformation in High-Capacity Lithium-Ion Batteries Caused by Charge and Discharge, Massachusetts 02138 Evidence has accumulated recently that a high-capacity elec- trode of a lithium-ion battery in the particle is high, possibly leading to fracture and cavitation. I. Introduction LITHIUM-ION batteries

Suo, Zhigang

360

Deformation of a liquid surface due to an impinging gas jet: A conformal mapping approach  

E-Print Network (OSTI)

Deformation of a liquid surface due to an impinging gas jet: A conformal mapping approach Andong He on it. The problem of a gas jet impinging on a liquid surface arises in several important industrial and Stewart11 observed two types of instabilities of the gas-liquid system: oscillations of the interface

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


361

Deformable B-Solids and Implicit Snakes for Localization and Tracking of SPAMM MRI-Data  

Science Conference Proceedings (OSTI)

To date, MRI-SPAMM data from different image slices have been analyzed independently. In this paper, we propose an approach for 3D tag localization and tracking of SPAMM data by a novel deformable B-solid. The solid is defined in terms of a 3D tensor ...

P. Radeva; A. Amini; J. Huang; E. MartÝ

1996-06-01T23:59:59.000Z

362

Gravity and tectonic patterns of Mercury: Effect of tidal deformation, spin-orbit resonance, nonzero  

E-Print Network (OSTI)

Gravity and tectonic patterns of Mercury: Effect of tidal deformation, spin-orbit resonance of spin-orbit resonance, nonzero eccentricity, despinning, and reorientation on Mercury's gravity and tectonic pattern. Large variations of the gravity and shape coefficients from the synchronous rotation

Nimmo, Francis

363

High performance computing for deformable image registration: Towards a new paradigm in adaptive radiotherapy  

Science Conference Proceedings (OSTI)

The advent of readily available temporal imaging or time series volumetric (4D) imaging has become an indispensable component of treatment planning and adaptive radiotherapy (ART) at many radiotherapy centers. Deformable image registration (DIR) is also used in other areas of medical imaging

Sanjiv S. Samant; Junyi Xia; P?nar Muyan-Ízšelik; John D. Owens

2008-01-01T23:59:59.000Z

364

An alternative calculation of the Casimir energy for kappa-deformed electrodynamics  

E-Print Network (OSTI)

A simple, but effcient way of calculating regularized Casimir energies suitable for non-trivial frequency spectra is briefly described and applied to the case of a kappa-deformed scalar field theory. The results are consistent with the ones obtained by other means.

D Pinheiro; F C Santos; A. C. Tort

2003-11-13T23:59:59.000Z

365

High-temperature deformation in the Neoproterozoic transpressional Ribeira belt, southeast Brazil  

E-Print Network (OSTI)

High-temperature deformation in the Neoproterozoic transpressional Ribeira belt, southeast Brazil^ncias da Universidade de Sa~o Paulo, Rua do Lago 562, Cep: 05508-080, Sa~o Paulo, SP, Brazil b Laboratoire Geologia, Universidade Federal de Ouro Preto, 35400-000, Ouro Pre^to, MG, Brazil Received 5 April 2001

Bascou, J├ęr├┤me

366

Approximate eigensolutions of the deformed Woods-Saxon potential via AIM  

E-Print Network (OSTI)

By using the Pekeris approximation, the Schr\\"{o}dinger equation is solved for the nuclear deformed Woods-Saxon potential within the framework of the asymptotic iteration method (AIM). The energy levels are worked out and the corresponding normalized eigenfunctions are obtained in terms of hypergeometric function.

Sameer M. Ikhdair; Babatunde James Falaye; Majid Hamzavi

2013-07-31T23:59:59.000Z

367

A Virtual Environment for Interactive Assembly Simulation: From Rigid Bodies to Deformable Cables  

E-Print Network (OSTI)

and response are necessary for the interaction with rigid bodies and with input devices used by the engineer Science Algorithms and Complexity Group Im Stadtwald D-66123 Saarbr┬Ęucken, Germany schoemer motivate the need for deformable objects, especially cables, by practical examples and explain our

Sch├Âmer, Elmar

368

Low energy collective modes of deformed superfluid nuclei within the finite amplitude method  

E-Print Network (OSTI)

Background: The major challenge for nuclear theory is to describe and predict global properties and collective modes of atomic nuclei. Of particular interest is the response of the nucleus to a time-dependent external field that impacts the low-energy multipole and beta-decay strength. Purpose: We propose a method to compute low-lying collective modes in deformed nuclei within the finite amplitude method (FAM) based on the quasiparticle random-phase approximation (QRPA). By using the analytic property of the response function, we find the QRPA amplitudes by computing the residua of the FAM amplitudes by means of a contour integration around the QRPA poles in a complex frequency plane. Methods: We use the superfluid nuclear density functional theory with Skyrme energy density functionals, FAM-QRPA approach, and the conventional matrix formulation of the QRPA (MQRPA). Results: We demonstrate that the complex-energy FAM-QRPA method reproduces low-lying collective states obtained within the conventional matrix formulation of the QRPA theory. Illustrative calculations are performed for the isoscalar monopole strength in deformed 24Mg and for low-lying K = 0 quadrupole vibrational modes of deformed Yb and Er isotopes. Conclusions: The proposed FAM-QRPA approach allows one to efficiently calculate low-lying collective modes in spherical and deformed nuclei throughout the entire nuclear landscape, including shape-vibrational excitations, pairing vibrational modes, and beta-decay rates.

Nobuo Hinohara; Markus Kortelainen; Witold Nazarewicz

2013-04-15T23:59:59.000Z

369

Reduce Nb3Sn Strand Deformation when Fabricating High Jc Rutherford Cables  

SciTech Connect

During Phase I, our efforts were to reduce subelements deformation when fabricating Nb3Sn Rutherford cables. Our first focus is on 217-sublement tube type strand. We successfully made a few billets in ├?┬?├?┬ż├?┬ó├?┬?├?┬Ł OD tube with different Cu spacing between subelements, and supplied the strands to Fermi Lab for cabling. Through the rolling test characterization, these types of strands did not have enough bonding between subelements to withstand the deformation. We saw copper cracking between subelements in the deformed strands. We scaled up the billet from ├?┬?├?┬ż├?┬ó├?┬?├?┬Ł OD to 1.5├?┬ó├?┬?├?┬Ł OD, and made two billets. This greatly improves the bonding. There is no copper cracking in the deformed strands when we scaled up the diameter of the billets. Fermi Lab successfully made cables using one of this improved strands. In their cables, no Cu cracking and no filament bridging occurred. We also successfully made a couple of billets with hex OD and round ID subelements for 61-subelement restack. Due to the lack of bonding, we could not judge its cabling property properly. But we know through this experiment, we could keep the Nb round, once we select the proper Cu spacing.

Dr. Xuan Peng

2012-12-17T23:59:59.000Z

370

Santa Ana Windflow in the Newhall Pass as Determined by an Analysis of Tree Deformation  

Science Conference Proceedings (OSTI)

A tree deformation study was conducted in a suburban area of the Newhall Pass (located to the north of Los Angeles, California) to determine the direction and intensity of the Santa Ana windflow. Trees were used to provide the large data base ...

Donald T. Kasper

1981-11-01T23:59:59.000Z

371

A nonlinear elastic deformable template for soft structure segmentation. Application to the heart  

E-Print Network (OSTI)

A nonlinear elastic deformable template for soft structure segmentation. Application to the heart of the heart's anatomy and motion from temporal image sequences, more precisely Magnetic Resonance Imaging (MRI) sequences. Currently, a clinical examination results in a stack of slices covering the whole heart

Rouchdy, Youssef

372

Gurson's Model: ALE Formulation and Strain Localization  

Science Conference Proceedings (OSTI)

This paper presents a brief review of Gurson's damage model, employed to describes the strength degradation in ductile metals submitted to large plastic deformations. The damage model is applied using finite elements and an Arbitrary Lagrangian-Eulerian formulation (ALE), to ensure a better quality to the finite elements mesh. The study of the combined application of ALE and Gurson approach to damage modeling and strain localization is the object of this paper.

Cunda, Luiz A. B. da [Departamento de Materiais e Construcao, Fundacao Universidade Federal do Rio Grande, Av. Italia, km 8, Campus Carreiros, 96201-900, Rio Grande, RS (Brazil); Creus, Guillermo J. [Centro de Mecanica Aplicada e Computacional, Universidade Federal do Rio Grande do Sul, Av. Osvaldo Aranha, 99, 3o andar, 90035-190, Porto Alegre, RS (Brazil)

2007-05-17T23:59:59.000Z

373

Earth pressures and deformations in civil infrastructure in expansive soils  

E-Print Network (OSTI)

This dissertation includes the three major parts of the study: volume change, and lateral earth pressure due to suction change in expansive clay soils, and design of civil infrastructure drilled pier, retaining wall and pavement in expansive soils. The volume change model in expansive clay has been refined to reinforce realistic characteristics of swelling and shrinkage behavior of expansive clay soils. Refinements include more realistic design soil suction versus depth profiles and improved characterizations of the effects of soil cracking, overburden stress, and lateral earth pressure. The refined model also includes an algorithm of assigning suctionvolumetric water content curves and diffusivity through the soil. The typical lateral earth pressure distribution during wetting against a stationary wall is proposed. The proposed stationary retaining wall-soil system in expansive soils includes an upper movement active zone and a lower anchor zone. MohrÔ s circles and failure envelopes are used to define the effective horizontal stress and shear failure in an unsaturated soil. The prediction of the horizontal pressures due to suction change in a soil is compared with the in situ measurement of natural horizontal pressures and the measurements from the large scale tests. It is found that agreement between the measured and predicted horizontal pressures is satisfactory. Case studies of axial and bending of the pier are presented with both uniform and non-uniform wetting. The pier case study for axial behavior shows a good agreement with a heave at ground surface and uplift forces. Three case studies for bending behavior of the pier and retaining wall are presented based on suction change. Pavement design program has been refined to extend the design capabilities into both flexible and rigid pavements supported by pavement treatments. The comparative case studies using both current and new methods in pavement design show that the current method criterion of 1-inch is unnecessarily conservative. Furthermore, the current method does not provide a means of anticipating subgrade shrinkage that will result in longitudinal cracking along the edge of the pavement. The design calculations with both methods lead to the conclusion that neither the swelling movement, as in the current method, nor the total movement, as in the new method, is a reliable indicator of likely acceptable pavement performance. Instead, all of these case studies show that it is important to use the predicted history of the present serviceability index and the international roughness index as the proper design guideline for an acceptable treatment of the subgrade of an expansive soil.

Hong, Gyeong Taek

2008-05-01T23:59:59.000Z

374

Branes in Poisson sigma models  

Science Conference Proceedings (OSTI)

In this review we discuss possible boundary conditions (branes) for the Poisson sigma model. We show how to carry out the perturbative quantization in the presence of a general pre-Poisson brane and how this is related to the deformation quantization of Poisson structures. We conclude with an open problem: the perturbative quantization of the system when the boundary has several connected components and we use a different pre-Poisson brane in every component.

Falceto, Fernando [Instituto de Biocomputacion y Fisica de Sistemas Complejos and Depto. Fisica Teorica Universidad de Zaragoza (Spain)

2010-07-28T23:59:59.000Z

375

Deformation of Olivine at Subduction Zone Conditions Determined from In situ Measurements with Synchrotron Radiation  

Science Conference Proceedings (OSTI)

We report measurements of the deformation stress for San Carlos olivine at pressures of 3-5 GPa, temperatures of 25-1150 C, and strain rates of 10{sup -7}-10{sup -5} s{sup -1}. We determine a deformation stress of approximately 2.5 GPa that is relatively temperature and strain rate independent in the temperature range of 400-900 C. The deformation experiments have been carried out on a deformation DIA (D-DIA) apparatus, Sam85, at X17B2, NSLS. Powder samples are used in these experiments. Enstatite (MgSiO{sub 3}) (3-5% total quality of sample) is used as the buffer to control the activity of silica. Ni foil is used in some experiments to buffer the oxygen fugacity. Water content is confirmed by IR spectra of the recovered samples. Samples are compressed at room temperature and are then annealed at 1200 C for at least 2 h before deformation. The total (plastic and elastic) strains (macroscopic) are derived from the direct measurements of the images taken by X-ray radiograph technique. The differential stresses are derived from the diffraction determined elastic strains. In the regime of 25-400 C, there is a small decrease of stress at steady state as temperature increases; in the regime of 400 C to the 'transition temperature', the differential stress at steady state ({approx}2.5 GPa) is relatively insensitive to the changes of temperature and strain rate; however, it drastically decreases to about 1 GPa and becomes temperature-dependent above the transition temperature and thereafter. The transition temperature is near 900 C. Above the transition temperature, the flow agrees with power law creep measurements of previous investigations. The anisotropy of differential stress in individual planes indicates that the deformation of olivine at low temperature is dominated by [0 0 1](1 0 0). Accounting to a slower strain rate in the natural system, the transition temperature for the olivine in the slab is most likely in the range of 570-660 C.

H Long; D Weidner; L Li; J Chen; L Wang

2011-12-31T23:59:59.000Z

376

Unified $(p,q; ?,?, l)$-deformation of oscillator algebra and two-dimensional conformal field theory  

E-Print Network (OSTI)

The unified $ (p,q; \\alpha,\\gamma, l)$-deformation of a number of well-known deformed oscillator algebras is introduced.The deformation is constructed by imputing new free parameters into the structure functions and by generalizing the defining relations of these algebras. The generalized Jordan-Schwinger and Holstein-Primakoff realizations of the $U_{pq}^{\\alpha \\gamma l}(su(2))$ algebra by the generalized $ (p,q; \\alpha,\\gamma, l)$-deformed operators are found. The generalized $ (p,q; \\alpha,\\gamma, l)$-deformation of the two-dimensional conformal field theory is established. By introducing the $ (p,q; \\alpha,\\gamma, l)$-operator product expansion (OPE) between the energy momentum tensor and primary fields, we obtain the $ (p,q; \\alpha,\\gamma, l)$-deformed centerless Virasoro algebra. The two-point correlation function of the primary generalized $ (p,q; \\alpha,\\gamma, l)$-deformed fields is calculated.

I. M. Burban

2013-09-13T23:59:59.000Z

377

On deforming a sector of a circular cylindrical tube into an intact tube: existence, uniqueness, and stability  

E-Print Network (OSTI)

Within the context of finite deformation elasticity theory the problem of deforming an open sector of a thick-walled circular cylindrical tube into a complete circular cylindrical tube is analyzed. The analysis provides a means of estimating the radial and circumferential residual stress present in an intact tube, which is a problem of particular concern in dealing with the mechanical response of arteries. The initial sector is assumed to be unstressed and the stress distribution resulting from the closure of the sector is then calculated in the absence of loads on the cylindrical surfaces. Conditions on the form of the elastic strain-energy function required for existence and uniqueness of the deformed configuration are then examined. Finally, stability of the resulting finite deformation is analyzed using the theory of incremental deformations superimposed on the finite deformation, implemented in terms of the Stroh formulation. The main results are that convexity of the strain energy as a function of a certain deformation variable ensures existence and uniqueness of the residually-stressed intact tube, and that bifurcation can occur in the closing of thick, widely opened sectors, depending on the values of geometrical and physical parameters. The results are illustrated for particular choices of these parameters, based on data available in the biomechanics literature.

Micehl Destrade; Jerry G. Murphy; Ray W. Ogden

2013-01-22T23:59:59.000Z

378

Mechanical model for ductility loss  

Science Conference Proceedings (OSTI)

A mechanical model was constructed to probe into the mechanism of ductility loss. Fracture criterion based on critical localized deformation was undertaken. Two microstructure variables were considered in the model. Namely, the strength ratio of grain boundary affected area to the matrix, ..cap omega.., and the linear fraction, x, of grain boundary affected area. A parametrical study was carried out. The study shows that the ductility is very sensitive to those microstructure parameters. The functional dependence of ductility to temperature as well as strain-rate, suggested by the model, is demonstrated to be consistent with the observation.

Hu, W.L.

1980-02-11T23:59:59.000Z

379

Aging in a Colloidal Glass in Creep Flow: Time-Stress Superposition  

E-Print Network (OSTI)

In this work, we study ageing behavior of aqueous laponite suspension, a model soft glassy material, in creep. We observe that viscoelastic behavior is time dependent and is strongly influenced by the deformation field; the effect is known to arise due to ageing and rejuvenation. We show that irrespective of strength of deformation field (shear stress) and age, when imposed time-scale is normalized with dominating relaxation mode of the system, universal ageing behavior is obtained demonstrating time-stress superposition; the phenomena that may be generic in variety of soft materials.

Yogesh M. Joshi; G. Ranjith; K. Reddy

2007-10-28T23:59:59.000Z

380

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

E-Print Network (OSTI)

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

Jain, Antone Kumar

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "viscoelastic deformation model" from the National Library of EnergyBeta (NLEBeta).
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381

Roles of nanoclusters in shear banding and plastic deformation of bulk metallic glasses  

Science Conference Proceedings (OSTI)

During the course of this research we published 33 papers in various physics/material journals. We select four representing papers in this report and their results are summarized as follows. I. To study shear banding process, it is pertinent to know the intrinsic shear strain rate within a propagating shear band. To this aim, we used nanoindentation technique to probe the mechanical response of a Au49Ag5.5Pd2.3Cu26.9Si16.3 bulk metallic glass in locality and found notable pop-in events associated with shear band emission. Using a free volume model and under the situation when temperature and stress/hardness are fixed result in an equation, which predicts that hardness serration caused by pop-in decreases exponentially with the strain rate. Our data are in good agreement with the prediction. The result also predicts that, when strain rate is higher than a critical strain rate of 1700 s^-1, there will be no hardness serration, thereby no pop-in. In other words, multiple shear bandings will take place and material will flow homogeneously. The critical strain rate of 1700 s^-1 can be treated as the intrinsic strain rate within a shear band. We subsequently carried out a simulation study and showed that, if the imposed strain rate was over , the shear band spacing would become so small that the entire sample would virtually behave like one major shear band. Using the datum strain rate =1700 s^-1 and based on a shear band nucleation model proposed by us, the size of a shear-band nucleus in Au-BMG was estimated to be 3 ├?┬?├?┬? 10^6 atoms, or a sphere of ~30 nm in diameter. II. Inspired by the peculiar result published in a Science article ├?┬ó├?┬?├?┬?Super Plastic Bulk Metallic Glasses at Room Temperature├?┬ó├?┬?├?┬Ł, we synthesized the Zr-based bulk metallic glass with a composition identical to that in the paper (Zr64.13Cu15.75Ni10.12Al10) and, subsequently, tested in compression at the same slow strain rate (~10^-4 s^-1). We found that the dominant deformation mode is always single shear. The stress-strain curve exhibited serrated pattern in the plastic region, which conventionally has been attributed to individual shear band propagation. The scanning electron micrographs taken from the deformed sample surface revealed regularly spaced striations. Analysis indicates that the observed stress-strain serrations are intimately related to the striations on the shear surface, suggesting the serrations were actually caused slip-and-stick shear along the principal shear plane. We further use video camera to conduct in situ compression experiments to unambiguously confirm the one-to-one temporal and spatial correspondence between the intermittent sliding and flow serration. This preferential shear band formation along the principal shear plane is, in fact, a natural consequence of Mode II crack, independent of strain softening or hardening, usually claimed in the literature. III. Flow serration in compression of metallic glasses is caused by the formation and propagation of localized shear bands. These shear bands propagate at an extremely high speed, so high that a load cell and load frame were unable to capture the details of the dynamic event. To subdue this problem, we conducted uniaxial compression on Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass using a high-speed camera to capture the sample image and also high-sensitivity strain gauges attached to the test samples to directly measure the strain. The displacement-time curves obtained from the test and a magnified version of the displacement burst reveals clearly a three-step (acceleration, steady-state, and deceleration) process during shear band propagation. The fastest propagating speed occurring at the steady state is calculated as 8├?┬?├?┬?10^2 ├?┬?├?┬Ám/s. This speed is about 1,000 times faster than the crosshead speed. This explains the gradual disappearance of flow serration at higher strain rates previously reported during compression of

Nieh, T.G.

2012-07-31T23:59:59.000Z

382

Roles of nanoclusters in shear banding and plastic deformation of bulk metallic glasses  

SciTech Connect

During the course of this research we published 33 papers in various physics/material journals. We select four representing papers in this report and their results are summarized as follows. I. To study shear banding process, it is pertinent to know the intrinsic shear strain rate within a propagating shear band. To this aim, we used nanoindentation technique to probe the mechanical response of a Au49Ag5.5Pd2.3Cu26.9Si16.3 bulk metallic glass in locality and found notable pop-in events associated with shear band emission. Using a free volume model and under the situation when temperature and stress/hardness are fixed result in an equation, which predicts that hardness serration caused by pop-in decreases exponentially with the strain rate. Our data are in good agreement with the prediction. The result also predicts that, when strain rate is higher than a critical strain rate of 1700 s^-1, there will be no hardness serration, thereby no pop-in. In other words, multiple shear bandings will take place and material will flow homogeneously. The critical strain rate of 1700 s^-1 can be treated as the intrinsic strain rate within a shear band. We subsequently carried out a simulation study and showed that, if the imposed strain rate was over , the shear band spacing would become so small that the entire sample would virtually behave like one major shear band. Using the datum strain rate =1700 s^-1 and based on a shear band nucleation model proposed by us, the size of a shear-band nucleus in Au-BMG was estimated to be 3 ├?┬?├?┬? 10^6 atoms, or a sphere of ~30 nm in diameter. II. Inspired by the peculiar result published in a Science article ├?┬ó├?┬?├?┬?Super Plastic Bulk Metallic Glasses at Room Temperature├?┬ó├?┬?├?┬Ł, we synthesized the Zr-based bulk metallic glass with a composition identical to that in the paper (Zr64.13Cu15.75Ni10.12Al10) and, subsequently, tested in compression at the same slow strain rate (~10^-4 s^-1). We found that the dominant deformation mode is always single shear. The stress-strain curve exhibited serrated pattern in the plastic region, which conventionally has been attributed to individual shear band propagation. The scanning electron micrographs taken from the deformed sample surface revealed regularly spaced striations. Analysis indicates that the observed stress-strain serrations are intimately related to the striations on the shear surface, suggesting the serrations were actually caused slip-and-stick shear along the principal shear plane. We further use video camera to conduct in situ compression experiments to unambiguously confirm the one-to-one temporal and spatial correspondence between the intermittent sliding and flow serration. This preferential shear band formation along the principal shear plane is, in fact, a natural consequence of Mode II crack, independent of strain softening or hardening, usually claimed in the literature. III. Flow serration in compression of metallic glasses is caused by the formation and propagation of localized shear bands. These shear bands propagate at an extremely high speed, so high that a load cell and load frame were unable to capture the details of the dynamic event. To subdue this problem, we conducted uniaxial compression on Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass using a high-speed camera to capture the sample image and also high-sensitivity strain gauges attached to the test samples to directly measure the strain. The displacement-time curves obtained from the test and a magnified version of the displacement burst reveals clearly a three-step (acceleration, steady-state, and deceleration) process during shear band propagation. The fastest propagating speed occurring at the steady state is calculated as 8├?┬?├?┬?10^2 ├?┬?├?┬Ám/s. This speed is about 1,000 times faster than the crosshead speed. This explains the gradual disappearance of flow serration at higher strain rates previously reported during compression of

Nieh, T.G.

2012-07-31T23:59:59.000Z

383

Role of deformation on giant resonances within the quasiparticle random-phase approximation and the Gogny force  

SciTech Connect

Fully consistent axially-symmetric-deformed quasiparticle random phase approximation (QRPA) calculations have been performed, in which the same Gogny D1S effective force has been used for both the Hartree-Fock-Bogolyubov mean field and the QRPA approaches. Giant resonances calculated in deformed {sup 26-28}Si and {sup 22-24}Mg nuclei as well as in the spherical {sup 30}Si and {sup 28}Mg isotopes are presented. Theoretical results for isovector-dipole and isoscalar monopole, quadrupole, and octupole responses are presented and the impact of the intrinsic nuclear deformation is discussed.

Peru, S.; Goutte, H. [CEA/DAM-Ile de France, Service de Physique Nucleaire, Bruyeres-le-Chatel, F-91297 Arpajon Cedex (France)

2008-04-15T23:59:59.000Z

384

Approximate analysis of the temperature induced stresses and deformations of composite shells  

Science Conference Proceedings (OSTI)

In this paper simple formulas are presented which can be used to estimate the response of composite plates and shells to hygrothermal loads. The layup of the shell can be arbitrary (i.e., it can be symmetric or unsymmetric, balanced or unbalanced). The formulas serve two purposes. First, they can be used to calculate directly the stresses, strains, and displacements caused by a temperature and a moisture gradient. Second, the formulas can be used to determine the 'effective' thermal and moisture expansion coefficients which are the parameters needed in more accurate numerical (FEM) calculations. The accuracies of the approximate formulas were assessed by sample problems. In these problems the hygrothermal deformations of cylinders and cylindrical segments were calculated by the present approximate formulas and by an exact, three-dimensional analysis. The results of the exact and approximate methods were compared. These comparisons showed that the approximate formulas yield the deformations with a high degree of accuracy. 18 refs.

Kollar, L.P. (Stanford Univ., Stanford, CA (United States))

1994-01-01T23:59:59.000Z

385

Finite-amplitude inhomogeneous plane waves in a deformed Mooney-Rivlin material  

E-Print Network (OSTI)

The propagation of finite-amplitude linearly-polarized inhomogeneous transverse plane waves is considered for a Mooney-Rivlin material maintained in a state of finite static homogeneous deformation. It is shown that such waves are possible provided that the directions of the normal to the planes of constant phase and of the normal to the planes of constant amplitude are orthogonal and conjugate with respect to the B-ellipsoid, where B is the left Cauchy-Green strain tensor corresponding to the initial deformation. For these waves, it is found that even though the system is non-linear, results on energy flux are nevertheless identical with corresponding results in the classical linearized elasticity theory. Byproducts of the results are new exact static solutions for the Mooney-Rivlin material.

Michel Destrade

2013-06-02T23:59:59.000Z

386

Monitoring crustal deformation in The Geysers-Clear Lake geothermal area, California  

DOE Green Energy (OSTI)

Geodetic surveys since 1972-1973 reveal significant crustal deformation in The Geysers-Clear Lake region. Resurveys of precise control networks are measuring both vertical and horizontal ground movement, with most of the change continuing in the area of geothermal fluid withdrawal. Preliminary evidence suggests right-lateral horizontal movement on northwest-trending fault systems and vertical and horizontal compression of the deep geothermal reservoir system. A direct correlaton is suggested between ground-surface deformation and subsurface pressure changes in the reservoir system. Although surface changes appear too small to be of environmental concern in The Geysers-Clear Lake region, they indicate hydrodynamic changes in the reservoir of significant import.

Lofgren, B.E.

1978-01-01T23:59:59.000Z

387

QRPA Calculations for Spherical and Deformed Nuclei With the Gogny Force  

Science Conference Proceedings (OSTI)

Fully consistent axially-symmetric-deformed Quasi-particle Random Phase Approximation (QRPA) calculations have been performed with the D1S Gogny force. Dipole responses have been calculated in Ne isotopes to study the existence of soft dipole modes in exotic nuclei. A comparison between QRPA and generator coordinate method with Gaussian overlap approximation results is done for low lying 2{sup +} states in N = 16 isotones and Ni isotopes.

Peru, S. [CEA, DAM, DIF, F-91297 Arpajon (France)

2009-08-26T23:59:59.000Z

388

Understanding the Interaction Between Localized Deformation in Materials and Environmentally Assisted Cracking  

Science Conference Proceedings (OSTI)

This report sets out to develop an understanding of the interaction between localized mechanical deformation in reactor structural materials (such as nickel-base alloys, austenitic stainless steels, or carbon and low-alloy steels) and their susceptibility to degradation by environmentally assisted cracking (EAC) after long-term exposure to light water reactor coolant. The main emphasis is on stress corrosion cracking (SCC), with and without the influence of irradiation, in the pressurized water reactor (...

2005-12-19T23:59:59.000Z

389

Perturbation hydrogen-atom spectrum in deformed space with minimal length  

E-Print Network (OSTI)

We study energy spectrum for hydrogen atom with deformed Heisenberg algebra leading to minimal length. We develop correct perturbation theory free of divergences. It gives a possibility to calculate analytically in the 3D case the corrections to $s$-levels of hydrogen atom caused by the minimal length. Comparing our result with experimental data from precision hydrogen spectroscopy an upper bound for the minimal length is obtained.

M. M. Stetsko; V. M. Tkachuk

2006-03-06T23:59:59.000Z

390

Deformation and shape transitions in hot rotating neutron deficient Te isotopes  

SciTech Connect

Evolution of the nuclear shapes and deformations under the influence of temperature and rotation is investigated in Te isotopes with neutron number ranging from the proton drip line to the stability valley. Spin dependent critical temperatures for the shape transitions in Te nuclei are computed. Shape transitions from prolate at low temperature and spin to oblate via triaxiality are seen with increasing neutron number and spin.

Aggarwal, Mamta [UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Kalina Campus, Mumbai 400 098 (India); Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005 (India); Mazumdar, I. [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005 (India)

2009-08-15T23:59:59.000Z

391

Diagnostics of the fine spectrum of a quantum well in laser heterostructures using ultrasonic deformation  

SciTech Connect

This paper describes a new acoustoelectronic effect in laser nanoheterostructures, which is caused by hole energy modulation and intermixing of hole wave functions in the quantum well of a laser structure in response to ultrasonic deformation. Experimental data are presented which indicate that the laser output intensity and polarisation direction vary periodically, with the acoustic wave period. Theoretical analysis of experimental data is used to assess parameters of the quantum well and the strain distribution in the heterostructure. (semiconductor lasers. physics and technology)

Kulakova, L A; Averkiev, Nikita S; Darinskii, A N; Yakhkind, E Z

2013-05-31T23:59:59.000Z

392

Double complex SUSY-transformations: deformations of real potentials and their spectral characteristics  

E-Print Network (OSTI)

In paper approach of double complex SUSY-transformations with not coincident complex energies of transformation is developed, allowing to deform given real potential $V_{1}$ with obtaining exact solutions. The explicit solutions of the deformation of shape of the potential, its wave function at arbitrary energy, not coincident with energies of transformation, wave functions at the energies of transformation are obtained, condition of keeping of continuity of the solutions and isospectral condition are determined. Using a rectangular well of finite width with infinitely high walls as the starting $V_{1}$ with discrete energy spectrum, by the proposed approach new types of deformation of this potential with deformation of the energy spectrum as a whole have been obtained. The new potential contains the rectangular well as own partial case (with simultaneous transformation of the shape of this new potential, energy spectrum, wave functions of all bound states, wave function at arbitrary energy into corresponding characteristics of the rectangular well at needed choice of parameters). Using null potential as the starting $V_{1}$ with continuous energy spectrum, new form of reflectionless real potential has been constructed. This potential generalizes well-known reflectionless potential of the type $V_{\\rm ref}(x) = A^{2}(1-2 {\\rm sech}^{2}{Ax})$, allowing: to pull down tails of the potential $V_{\\rm ref}$ in the asymptotic regions up to zero (with keeping of nonzero depth); to pull down continuously the depth of the hole; to displace arbitrary along axis $x$ the hole with its passing through zero; to create and to increase the second hole, transforming $V_{\\rm ref}$ into double-well potential; to control continuously and simply the asymmetry of the shape of such reflectionless potential.

Sergei P. Maydanyuk

2007-10-22T23:59:59.000Z

393

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

394

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

395

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Wednesday, 25 November 2009 00:00 Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

396

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

397

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

398

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

399

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

400

Investigation of the carbon dioxide sorption capacity and structural deformation of coal  

Science Conference Proceedings (OSTI)

Due to increasing atmospheric CO2 concentrations causing the global energy and environmental crises, geological sequestration of carbon dioxide is now being actively considered as an attractive option to mitigate greenhouse gas emissions. One of the important strategies is to use deep unminable coal seams, for those generally contain significant quantities of coal bed methane that can be recovered by CO2 injection through enhanced coal bed natural gas production, as a method to safely store CO2. It has been well known that the adsorbing CO2 molecules introduce structural deformation, such as distortion, shrinkage, or swelling, of the adsorbent of coal organic matrix. The accurate investigations of CO2 sorption capacity as well as of adsorption behavior need to be performed under the conditions that coals deform. The U.S. Department of Energy-National Energy Technology Laboratory and Regional University Alliance are conducting carbon dioxide sorption isotherm experiments by using manometric analysis method for estimation of CO2 sorption capacity of various coal samples and are constructing a gravimetric apparatus which has a visual window cell. The gravimetric apparatus improves the accuracy of carbon dioxide sorption capacity and provides feasibility for the observation of structural deformation of coal sample while carbon dioxide molecules interact with coal organic matrix. The CO2 sorption isotherm measurements have been conducted for moist and dried samples of the Central Appalachian Basin (Russell County, VA) coal seam, received from the SECARB partnership, at the temperature of 55 C.

Hur, Tae-Bong; Fazio, James; Romanov, Vyacheslav; Harbert, William

2010-01-01T23:59:59.000Z

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


401

Dynamic Rotor Deformation and Vibration Monitoring Using a Non-Incremental Laser Doppler Distance Sensor  

Science Conference Proceedings (OSTI)

Monitoring rotor deformations and vibrations dynamically is an important task for improving the safety and the lifetime as well as the energy efficiency of motors and turbo machines. However, due to the high rotor speed encountered in particular at turbo machines, this requires concurrently a high measurement rate and high accuracy, which can not be fulfilled by most commercially available sensors. To solve this problem, we developed a non-incremental laser Doppler distance sensor (LDDS), which is able to measure simultaneously the in-plane velocity and the out-of-plane position of moving rough solid objects with micrometer precision. In addition, this sensor concurrently offers a high temporal resolution in the microsecond range, because its position uncertainty is in principle independent of the object velocity in contrast to conventional distance sensors, which is a unique feature of the LDDS. Consequently, this novel sensor enables precise and dynamic in-process deformation and vibration measurements on rotating objects, such as turbo machine rotors, even at very high speed. In order to evidence the capability of the LDDS, measurements of rotor deformations (radial expansion), vibrations and wobbling motions are presented at up to 50,000 rpm rotor speed.

Pfister, Thorsten; Guenther, Philipp; Dreier, Florian; Czarske, Juergen [Technische Universitaet Dresden, Faculty of Electrical Engineering and Information Technology, Laboratory for Measurement and Testing Techniques, Helmholtzstrasse 18, D-01062 Dresden (Germany)

2010-05-28T23:59:59.000Z

402

Micropillar compression technique applied to micron-scale mudstone elasto-plastic deformation.  

Science Conference Proceedings (OSTI)

Mudstone mechanical testing is often limited by poor core recovery and sample size, preservation and preparation issues, which can lead to sampling bias, damage, and time-dependent effects. A micropillar compression technique, originally developed by Uchic et al. 2004, here is applied to elasto-plastic deformation of small volumes of mudstone, in the range of cubic microns. This study examines behavior of the Gothic shale, the basal unit of the Ismay zone of the Pennsylvanian Paradox Formation and potential shale gas play in southeastern Utah, USA. Precision manufacture of micropillars 5 microns in diameter and 10 microns in length are prepared using an ion-milling method. Characterization of samples is carried out using: dual focused ion - scanning electron beam imaging of nano-scaled pores and distribution of matrix clay and quartz, as well as pore-filling organics; laser scanning confocal (LSCM) 3D imaging of natural fractures; and gas permeability, among other techniques. Compression testing of micropillars under load control is performed using two different nanoindenter techniques. Deformation of 0.5 cm in diameter by 1 cm in length cores is carried out and visualized by a microscope loading stage and laser scanning confocal microscopy. Axisymmetric multistage compression testing and multi-stress path testing is carried out using 2.54 cm plugs. Discussion of results addresses size of representative elementary volumes applicable to continuum-scale mudstone deformation, anisotropy, and size-scale plasticity effects. Other issues include fabrication-induced damage, alignment, and influence of substrate.

Michael, Joseph Richard; Chidsey, Thomas (Utah Geological Survey, Salt Lake City, UT); Heath, Jason E.; Dewers, Thomas A.; Boyce, Brad Lee; Buchheit, Thomas Edward

2010-12-01T23:59:59.000Z

403

Field-scale and wellbore modeling of compaction-induced casing failures  

SciTech Connect

Presented in this paper are the results and verification of field- and wellbore-scale large deformation, elasto-plastic, geomechanical finite element models of reservoir compaction and associated casing damage. The models were developed as part of a multidisciplinary team project to reduce the number of costly well failures in the diatomite reservoir of the South Belridge Field near Bakersfield, California. Reservoir compaction of high porosity diatomite rock induces localized shearing deformations on horizontal weak-rock layers and geologic unconformities. The localized shearing deformations result in casing damage or failure. Two-dimensional, field-scale finite element models were used to develop relationships between field operations, surface subsidence, and shear-induced casing damage. Pore pressures were computed for eighteen years of simulated production and water injection, using a three-dimensional reservoir simulator. The pore pressures were input to the two-dimensional geomechanical field-scale model. Frictional contact surfaces were used to model localized shear deformations. To capture the complex casing-cement-rock interaction that governs casing damage and failure, three-dimensional models of a wellbore were constructed, including a frictional sliding surface to model localized shear deformation. Calculations were compared to field data for verification of the models.

Hilbert, L.B. Jr.; Gwinn, R.L.; Moroney, T.A.; Deitrick, G.L.

1999-06-01T23:59:59.000Z

404

Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations  

SciTech Connect

This paper presents recent advancement in and applications of TOUGH-FLAC, a simulator for multiphase fluid flow and geomechanics. The TOUGH-FLAC simulator links the TOUGH family multiphase fluid and heat transport codes with the commercial FLAC{sup 3D} geomechanical simulator. The most significant new TOUGH-FLAC development in the past few years is a revised architecture, enabling a more rigorous and tight coupling procedure with improved computational efficiency. The applications presented in this paper are related to modeling of crustal deformations caused by deep underground fluid movements and pressure changes as a result of both industrial activities (the In Salah CO{sub 2} Storage Project and the Geysers Geothermal Field) and natural events (the 1960s Matsushiro Earthquake Swarm). Finally, the paper provides some perspectives on the future of TOUGH-FLAC in light of its applicability to practical problems and the need for high-performance computing capabilities for field-scale problems, such as industrial-scale CO{sub 2} storage and enhanced geothermal systems. It is concluded that despite some limitations to fully adapting a commercial code such as FLAC{sup 3D} for some specialized research and computational needs, TOUGH-FLAC is likely to remain a pragmatic simulation approach, with an increasing number of users in both academia and industry.

Rutqvist, J.

2010-06-01T23:59:59.000Z

405

Indentation-induced mechanical deformation behaviors of AlN thin films deposited on c-plane sapphire  

Science Conference Proceedings (OSTI)

The mechanical properties and deformation behaviors of AlN thin films deposited on c-plane sapphire substrates by helicon sputtering method were determined using the Berkovich nanoindentation and cross-sectional transmission electron microscopy (XTEM). ...

Sheng-Rui Jian; Jenh-Yih Juang

2012-01-01T23:59:59.000Z

406

Evaluation of two-dimensional displacement components of symmetrical deformation by phase-shifting electronic speckle pattern interferometry  

Science Conference Proceedings (OSTI)

A method for the isolation of two-dimensional (2D) displacement components by using one phase map obtained by phase-shifting electronic speckle pattern interferometry (ESPI)is presented. When the typical ESPI is used for displacement measurement, a mixed phase distribution of deformation is measured. If the deformation of the object is symmetrical, two components of deformation can be separated from each other by using the mixed phase distribution. We turn over the mixed phase map first to obtain the second phase map, and then overlap them. Two displacement components can be separated from each other by boundary alignment and algebraic calculation between the two phase maps. This method has been proved feasible by a typical three-point bending experiment. Some experimental results are offered and compared with the results obtained by a dual-beam symmetrical illuminations experiment. This technique presented provides an alternative approach to 2D deformation measurement.

Sun Ping

2007-05-20T23:59:59.000Z

407

The development of orogenic plateaus : Plateaus: case studies examining relationships between tectonics, crustal strength, surface deformation, and plateau morphology  

E-Print Network (OSTI)

This thesis addresses processes associated with the uplift, deformation, and erosion of orogenic plateaus. The timing and mechanisms of uplift of the Tibetan Plateau and the Altiplano are the subject of ongoing debate. ...

Cook, Kristen Lee

2008-01-01T23:59:59.000Z

408

Deformation Mechanisms  

Science Conference Proceedings (OSTI)

Mar 14, 2012... changes through shockwaves, thereby leading to dramatic improvements in fatigue and crack propagation resistance of alloys. We reportá...

409

Exactly Solvable Model for the Decay of Superdeformed Nuclei  

E-Print Network (OSTI)

The history and importance of superdeformation in nuclei is briefly discussed. A simple two-level model is then employed to obtain an elegant expression for the branching ratio for the decay via the E1 process in the normal-deformed band of superdeformed nuclei. From this expression, the spreading width Gamma^downarrow for superdeformed decay is found to be determined completely by experimentally known quantities. The accuracy of the two-level approximation is verified by considering the effects of other normal-deformed states. Furthermore, by using a statistical model of the energy levels in the normal-deformed well, we can obtain a probabilistic expression for the tunneling matrix element V.

B. R. Barrett; D. M. Cardamone; C. A. Stafford

2005-08-19T23:59:59.000Z

410

Scalar field propagation in the phi^4 kappa-Minkowski model  

E-Print Network (OSTI)

In this article we use the noncommutative (NC) kappa-Minkowski phi^4 model based on the kappa-deformed star product, ({*}_h). The action is modified by expanding up to linear order in the kappa-deformation parameter a, producing an effective model on commutative spacetime. For the computation of the tadpole diagram contributions to the scalar field propagation/self-energy, we anticipate that statistics on the kappa-Minkowski is specifically kappa-deformed. Thus our prescription in fact represents hybrid approach between standard quantum field theory (QFT) and NCQFT on the kappa-deformed Minkowski spacetime, resulting in a kappa-effective model. The propagation is analyzed in the framework of the two-point Green's function for low, intermediate, and for the Planckian propagation energies, respectively. Semiclassical/hybrid behavior of the first order quantum correction do show up due to the kappa-deformed momentum conservation law. For low energies, the dependence of the tadpole contribution on the deformation...

Meljanac, S; Trampetic, J; Wohlgenannt, M

2011-01-01T23:59:59.000Z

411

Shape coexistence near the neutron number N=20: First identification of the E0 decay from the deformed 0^+_2 state in 30Mg  

E-Print Network (OSTI)

The 1789 keV level in 30Mg was identified as the first excited 0^+ state by measuring its E0 transition to the ground state. The measured small value of rho^2(E0,0^+_2 --> 0^+_1) = 5.7(14) x 10^-3 implies a very small mixing of competing configurations with largely different intrinsic quadrupole deformation near N=20. Axially symmetric Beyond-Mean-Field configuration mixing calculations identify the ground state of 30Mg to be based on neutron configurations below the N=20 shell closure, while the excited 0^+ state mainly consists of a two neutrons excitated into the nu1 f_{7/2} orbital. Using a two-level model, a mixing amplitude of 0.08(4) can be derived.

W. Schwerdtfeger; P. G. Thirolf; K. Wimmer; D. Habs; H. Mach; T. R. Rodriguez; V. Bildstein; J. L. Egido; L. M. Fraile; R. Gernhaeuser; R. Hertenberger; K. Heyde; P. Hoff; H. Huebel; U. Koester; T. Kroell; R. Kruecken; R. Lutter; T. Morgan; P. Ring

2008-08-02T23:59:59.000Z

412

An Experimental Study of Deformation and Fracture of a Nanostructured Metallic Material  

E-Print Network (OSTI)

The mechanical properties of materials strongly depend on their microstructure. Therefore, engineering the material's microstructure can lead to improving its mechanical properties. One method for enhancing the strength of metallic materials consists of refining the grain size down to the nanometer scale. Such nanostructured materials possess remarkable strength without using conventional metallurgical strengthening methods. However, this strength often comes at the expense of workhardening capacity, thus favoring flow localization and loss of ductility and toughness. The deformation behavior of nanostructured metallic materials has been extensively studied in the literature. However, little is known of their fracture behavior. In this study, the mechanical behavior of a nanostructured, nearly pure material is investigated in order to link processing conditions, microstructure, and fracture locus in stress space. With focus laid on BCC materials which can undergo a ductile-to-brittle transition, Interstitial- Free (IF) steel is chosen. The microstructure is refined using Severe Plastic Deformation (SPD) to achieve ultra-fine grain (UFG) materials with grain sizes in the range 100nm- 1 mu m. Equal Channel Angular Extrusion (ECAE) is used to obtain three types of UFG-IF steel microstructures by varying the extrusion rate and processing temperature. The deformation behavior is investigated for the three UFG materials using round smooth bars and is compared with the behavior of the as-received material. The damage behavior and the fracture mechanisms are studied using tensile round notched bars with varying notch radii. The findings indicate a remarkable combination of strength and notch ductility at room temperature, including for the material with the finest microstructure. They also point to the need for careful characterization of temperature effects before such materials can be considered in structural applications.

Abdel Al, Nisrin Rizek

2009-12-01T23:59:59.000Z

413

Fatigue and Creep-Fatigue Deformation of an Ultra-Fine Precipitate Strengthened Advanced Austenitic Alloy  

SciTech Connect

An advanced austenitic alloy, HT-UPS (high-temperature ultrafine-precipitation-strengthened), has been identified as an ideal candidate material for the structural components of fast reactors and energy-conversion systems. HT-UPS alloys demonstrate improved creep resistance relative to 316 stainless steel (SS) through additions of Ti and Nb, which precipitate to form a widespread dispersion of stable nanoscale metallic carbide (MC) particles in the austenitic matrix. The low-cycle fatigue and creep-fatigue behavior of an HT-UPS alloy have been investigated at 650 ░C and a 1.0% total strain, with an R-ratio of -1 and hold times at peak tensile strain as long as 150 min. The cyclic deformation response of HT-UPS is directly compared to that of standard 316 SS. The measured values for total cycles to failure are similar, despite differences in peak stress profiles and in qualitative observations of the deformed microstructures. Crack propagation is primarily transgranular in fatigue and creep-fatigue of both alloys at the investigated conditions. Internal grain boundary damage in the form of fine cracks resulting from the tensile hold is present for hold times of 60 min and longer, and substantially more internal cracks are quantifiable in 316 SS than in HT-UPS. The dislocation substructures observed in the deformed material differ significantly; an equiaxed cellular structure is observed in 316 SS, whereas in HT-UPS the microstructure takes the form of widespread and relatively homogenous tangles of dislocations pinned by the nanoscale MC precipitates. The significant effect of the fine distribution of precipitates on observed fatigue and creep-fatigue response is described in three distinct behavioral regions as it evolves with continued cycling.

M.C. Carroll; L.J. Carroll

2012-10-01T23:59:59.000Z

414

DEFORMATION BEHAVIOR OF A 70/30 ALPHA BRASS IN PLANE STRESS/PLANE STRAIN  

E-Print Network (OSTI)

Generally a simple power law ~ = K E " (where K and n are empirical constants called the strength coefficient and the work hardening coefficient respectively) is used to describe plastic stress-strain dependence of deformable metals (1,2). This equation was employed by Low (3) to describe the uniaxial tensile behavior of an annealed 70/30 brass. The slope of the corresponding double logarithmic true stress-true strain plot gives a single value of n. However, this fit is not always adequate.

P. A. Sundaram; D. Rodriguez; S. Santiago

1993-01-01T23:59:59.000Z

415

Photon pressure induced test mass deformation in gravitational-wave detectors  

E-Print Network (OSTI)

A widely used assumption within the gravitational-wave community has so far been that a test mass acts like a rigid body for frequencies in the detection band, i.e. for frequencies far below the first internal resonance. In this article we demonstrate that localized forces, applied for example by a photon pressure actuator, can result in a non-negligible elastic deformation of the test masses. For a photon pressure actuator setup used in the gravitational wave detector GEO600 we measured that this effect modifies the standard response function by 10% at 1 kHz and about 100% at 2.5 kHz.

S. Hild; M. Brinkmann; K. Danzmann; H. Grote; M. Hewitson; J. Hough; H. Lueck; I. Martin; K. Mossavi; N. Rainer; S. Reid; J. R. Smith; K. Strain; M. Weinert; P. Willems; B. Willke; W. Winkler

2007-10-05T23:59:59.000Z

416

Surface defects, the superconformal index and q-deformed Yang-Mills  

E-Print Network (OSTI)

Recently a prescription to compute the four-dimensional N = 2 superconformal index in the presence of certain BPS surface defects has been given. These surface defects are labelled by symmetric representations of SU(N). In the present paper we give a prescription to compute the superconformal index in the presence of surface defects labelled by arbitrary representations of SU(N). Furthermore, we extend the dictionary between the N = 2 superconformal Schur-index and correlators of q-deformed Yang-Mills to incorporate such surface defects.

Luis F. Alday; Mathew Bullimore; Martin Fluder; Lotte Hollands

2013-03-19T23:59:59.000Z

417

Deformation of a thin, elastic plate to a deep parabolic cylinder  

DOE Green Energy (OSTI)

Equations governing the elastic deformation of thin plates through large displacements to deep parabolic cylinders are presented and solved. The solution consists of expressions for a spatially distributed surface pressure and uniform rim loads which, when applied to the plate, produce the specified, deep parabolic cylindrical shape. These forming loads are written in dimensionless form for parabolic cylinders of arbitrary focal length and arbitrary rim to rim aperture. Numerical results are presented and limiting values are discussed. The solution and results find immediate application to mechanical forming and adhesive retention of parabolic solar collector components.

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

1982-02-01T23:59:59.000Z

418

THE EFFECTS OF HYDROGEN, TRITIUM, AND HEAT TREATMENT ON THE DEFORMATION AND FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL  

SciTech Connect

The deformation and fracture toughness properties of forged stainless steels pre-charged with tritium were compared to the deformation and fracture toughness properties of the same steels heat treated at 773 K or 873 K and precharged with hydrogen. Forged stainless steels pre-charged with tritium exhibit an aging effect: Fracture toughness values decrease with aging time after precharging because of the increase in concentration of helium from tritium decay. This study shows that forged stainless steels given a prior heat treatment and then pre-charged with hydrogen also exhibit an aging effect: Fracture toughness values decrease with increasing time at temperature. A microstructural analysis showed that the fracture toughness reduction in the heat-treated steels was due to patches of recrystallized grains that form within the forged matrix during the heat treatment. The combination of hydrogen and the patches of recrystallized grains resulted in more deformation twinning. Heavy deformation twinning on multiple slip planes was typical for the hydrogen-charged samples; whereas, in the non-charged samples, less twinning was observed and was generally limited to one slip plane. Similar effects occur in tritium pre-charged steels, but the deformation twinning is brought on by the hardening associated with decay helium bubbles in the microstructure.

Morgan, M.; Tosten, M.; Chapman, G.

2013-09-06T23:59:59.000Z

419

Effective-stress-law behavior of Austin chalk rocks for deformation and fracture conductivity  

SciTech Connect

Austin chalk core has been tested to determine the effective law for deformation of the matrix material and the stress-sensitive conductivity of the natural fractures. For deformation behavior, two samples provided data on the variations of the poroelastic parameter, {alpha}, for Austin chalk, giving values around 0.4. The effective-stress-law behavior of a Saratoga limestone sample was also measured for the purpose of obtaining a comparison with a somewhat more porous carbonate rock. {alpha} for this rock was found to be near 0.9. The low {alpha} for the Austin chalk suggests that stresses in the reservoir, or around the wellbore, will not change much with changes in pore pressure, as the contribution of the fluid pressure is small. Three natural fractures from the Austin chalk were tested, but two of the fractures were very tight and probably do not contribute much to production. The third sample was highly conductive and showed some stress sensitivity with a factor of three reduction in conductivity over a net stress increase of 3000 psi. Natural fractures also showed a propensity for permanent damage when net stressed exceeded about 3000 psi. This damage was irreversible and significantly affected conductivity. {alpha} was difficult to determine and most tests were inconclusive, although the results from one sample suggested that {alpha} was near unity.

Warpinski, N.R.; Teufel, L.W.

1994-08-01T23:59:59.000Z

420

Deformation Behavior and TExture Evolution of Steel Alloys under Axial-Torsional Loading  

SciTech Connect

Using hollow cylinder samples with suitable geometry obtained from round bar stock, the deformation behavior of bcc Fe based 12L14 steel alloy is evaluated under multi-axial conditions. A stacked strain gage rosette and extensometer mounted on the cylindrical surface at the mid height of the specimen provided strain tensor as a function of applied stress for pure tensile and torsion tests prior to yielding. This study examines elastic and yield behavior and effects of these with respect to texture evolution. Hollow cylinder specimen geometry (tubes) with small wall thickness and relatively (to its thickness) large inner diameter is used. The variation of observed yield surface in deviatoric plane and the effect on mode of deformation (tension versus torsion versus its combination) on stress-strain behavior is discussed. Bulk texture was studied using neutron time-of-flight diffractometer at High-Pressure-Preferred Orientation (HIPPO) - Los Alamos Neutron Science Center (LANSCE) instrument and the evolution of texture and related anisotropy for pure tension versus torsion are also included.

Siriruk, A.; Kant, M.; Penumadu, D.; Garlea, E.; Vogel, S.

2011-06-01T23:59:59.000Z

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


421

Deformation Trend Extraction Based on Multi-Temporal InSAR in Shanghai  

E-Print Network (OSTI)

Abstract: Shanghai is a modern metropolis characterized by high urban density and anthropogenic ground motions. Although traditional deformation monitoring methods, such as GPS and spirit leveling, are reliable to millimeter accuracy, the sparse point subsidence information makes understanding large areas difficult. Multiple temporal space-borne synthetic aperture radar interferometry is a powerful high-accuracy (sub-millimeter) remote sensing tool for monitoring slow ground deformation for a large area with a high point density. In this paper, the Interferometric Point Target Time Series Analysis method is used to extract ground subsidence rates in Shanghai based on 31 C-Band and 35 X-Band synthetic aperture radar (SAR) images obtained by Envisat and COSMO SkyMed (CSK) satellites from 2007 to 2010. A significant subsidence funnel that was detected is located in the junction place between the Yangpu and the Hongkou Districts. A t-test is formulated to judge the agreements between the subsidence results obtained by SAR and by spirit leveling. In addition, four profile lines crossing the subsidence funnel area are chosen for a comparison of ground subsidence rates, which were obtained by the two different band

Jie Chen; Jicang Wu; Lina Zhang; Junping Zou; Guoxiang Liu; Rui Zhang; Bing Yu

2013-01-01T23:59:59.000Z

422

Modeling subsidence due to geothermal fluid production  

DOE Green Energy (OSTI)

Currently, liquid dominated geothermal systems hold the maximum promise for exploiting geothermal energy in the United States. The principal characteristic of such systems is that most of the heat is transferred by flowing water, which also controls subsurface fluid pressures and stress changes. The reduction in pore pressures brought about by geothermal fluid extraction is potentially capable of causing appreciable deformation of the reservoir rocks leading to displacements at the land surface. In order to foresee the pattern and magnitude of potential ground displacements in and around producing liquid dominated geothermal fields, a numerical model has been developed. Conceptually, the simulator combines conductive and convective heat transfer in a general three dimensional heterogeneous porous medium with a one-dimensional deformation of the reservoir rocks. The capabilities of the model and its potential applicability to field cases are illustrated with examples considering the effects of temperature and pressure dependent properties, material heterogeneities and previous stress history.

Lippmann, M.J.; Narasimhan, T.N.; Witherspoon, P.A.

1977-10-01T23:59:59.000Z

423

Galerkin method to model thin free surface flows  

E-Print Network (OSTI)

Viscoelastic thin films with free surface are important in industry as well as in nature. However, there does not exist a robust and systematic framework to analyze such films. Lubrication approximations, largely successful ...

Lee. Sungyon

2007-01-01T23:59:59.000Z

424

Plastic deformation of submicron-sized crystals studied by in-situ Kikuchi diffraction and dislocation imaging  

Science Conference Proceedings (OSTI)

The plastic deformation of submicron-size copper single crystals in the form of pillars has been characterized during in-situ compression in the transmission electron microscope up to strains of 28-33% using a state-of-the-art holder (PI-95 PicoIndenter). The dimensions of the crystals used were approx. 500 Multiplication-Sign 250 Multiplication-Sign 200 nm{sup 3} with the compression axis oriented 1.6 Degree-Sign from [110]. Local crystallographic orientations have been determined with high accuracy using a Kikuchi diffraction method and glide of dislocations over a pillar has also been observed directly by dark field imaging. The variation in the local orientation during deformation has been followed by in-situ convergent beam electron Kikuchi diffraction. The in-situ observations have been followed up by post-deformation measurements with the samples still mounted in the electron microscope. Crystal breakup following localized deformation was observed in two of three crystals examined, and for all crystals the direction of rotation during deformation is in agreement with slip taking place on a subset of the four slip systems, with the highest Schmid factors on the (111) and (- 1-11) slip planes. A diffraction-based Burgers vector analysis confirms that the active dislocations are from slip systems with the highest Schmid factors. These results from testing of micropillars are in good agreement with the deformation behaviour previously reported for both single- and poly-crystal samples with dimensions in the millimetre range. - Highlights: Black-Right-Pointing-Pointer We performed in-situ plastic deformation of submicron-sized copper single crystals. Black-Right-Pointing-Pointer We measured in-situ and ex-situ crystal rotation and imaged dislocation activities. Black-Right-Pointing-Pointer We measured crystallographic orientations and analyzed dislocation Burgers vectors. Black-Right-Pointing-Pointer Crystals' rotation in agreement with slip of dislocations with highest Schmid factor. Black-Right-Pointing-Pointer These results in good agreement with millimeter-scale samples' deformation behavior.

Zhang Xiaodan, E-mail: xzha@dtu.dk [Danish-Chinese Center for Nanometals, Materials Science and Advanced Characterization, Department for Wind Energy, Risoe Campus, Technical University of Denmark, DK-4000 Roskilde (Denmark); Godfrey, Andrew [Laboratory of Advanced Materials, Dept. Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Winther, Grethe [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Hansen, Niels; Huang Xiaoxu [Danish-Chinese Center for Nanometals, Materials Science and Advanced Characterization, Department for Wind Energy, Risoe Campus, Technical University of Denmark, DK-4000 Roskilde (Denmark)

2012-08-15T23:59:59.000Z

425

Parametric vibrations and stability of viscoelastic shells  

E-Print Network (OSTI)

2007; M.H. Ilyasov ( ) Azerbaijan National Academy ofdistrict, Baku 1003, Azerbaijan e-mail: mhan@istanbul.edu.tr

Ilyasov, M. H.

2010-01-01T23:59:59.000Z

426

Viscoelastic properties of bamboo R. S. Lakes  

E-Print Network (OSTI)

, as well as coal, amber and oil shale for comparison [3]. Woods such as spruce and beech exhibit peaks

Evans, Paul G.

427

Computationally efficient modelling of pattern dependencies in the micro-embossing of thermoplastic polymers  

Science Conference Proceedings (OSTI)

We present a highly computationally efficient way to simulate the deformation of a polymeric layer when embossed with an arbitrarily patterned stamp. Two simplified material models are considered: a purely elastic model, which is useful when the material ... Keywords: Computer-aided design, Hot micro-embossing, PMMA, Pattern dependencies, Simulation

Hayden Taylor; Duane Boning; Ciprian Iliescu; Bangtao Chen

2008-05-01T23:59:59.000Z

428

A simplified implementation of a gradient-enhanced damage model with transient length scale effects  

Science Conference Proceedings (OSTI)

Gradient-enhanced damage models with constant gradient activity suffer from spurious damage growth at high deformation levels. This issue was resolved by Geers et al. (Comput Methods Appl Mech Eng 160(1---2):133---153, 1998) by expressing the gradient ... Keywords: Continuum damage mechanics, Gradient-enhanced damage models, Regularized media, Transient internal length scale

S. Saroukhani; R. Vafadari; A. Simone

2013-06-01T23:59:59.000Z

429

Growth of compaction bands: A new deformation mode for porous rock  

SciTech Connect

Compaction bands are thin, tabular zones of grain breakage and reduced porosity that are found in sandstones. These structures may form due to tectonic stresses or as a result of local stresses induced during production of fluids from wells, resulting in barriers to fluid (oil, gas, water) movement in sandstone reservoirs. To gain insight into the formation of compaction bands the authors have produced them in the laboratory. Acoustic emission locations were used to define and track the thickness of compaction bands throughout the stress history during axisymmetric compression experiments. Narrow zones of intense acoustic emission, demarcating the boundaries between the uncompacted and compacted regions were found to develop. Unexpectedly, these boundaries moved at velocities related to the fractional porosity reduction across the boundary and to the imposed specimen compression stress. This appears to be a previously unrecognized, fundamental mode of deformation of a porous, granular material subjected to compressive loading with significant implications for the production of hydrocarbons.

OLSSON,WILLIAM A.; HOLCOMB,DAVID J.

2000-03-14T23:59:59.000Z

430

On Constitutive Equations and Effective Stress for Deformable, Double Porosity Media  

E-Print Network (OSTI)

Tuncay and Corapcioglu [1995] used volume averaging methods to derive an effective stress principle for the bulk volumetric strain in a deformable double-porosity medium. The coefficients of the matrix pore pressure and fracture pore pressure in their equation for the effective stress are shown to be identical to those which can be obtained from the constitutive equation approach of Berryman and Wang (1995). Representative values for a fractured Berea sandstone show that a change in pore pressure within matrix blocks produces about 10% of the volume change due to an equal but opposite change in confining pressure, whereas the same change in pore pressure within fractures is about 90% as effective. A similar result is true for Westerly granite. 1 Introduction The theory of poroelasticity lies at the intersection of mechanics of porous media and fluid flow within porous media. As a consequence, papers dealing with poroelasticity appear in journals that appeal primarily to one or the oth...

Herbert F. Wang; James G. Berryman

1996-01-01T23:59:59.000Z

431

Fibre optical measuring network based on quasi-distributed amplitude sensors for detecting deformation loads  

SciTech Connect

A new design of a sensitive element for a fibre optical sensor of deformation loads is proposed. A distributed fibre optical measuring network, aimed at determining both the load application point and the load mass, has been developed based on these elements. It is shown that neural network methods of data processing make it possible to combine quasi-distributed amplitude sensors of different types into a unified network. The results of the experimental study of a breadboard of a fibre optical measuring network are reported, which demonstrate successful reconstruction of the trajectory of a moving object (load) with a spatial resolution of 8 cm, as well as the load mass in the range of 1 - 10 kg with a sensitivity of 0.043 kg{sup -1}. (laser optics 2012)

Kul'chin, Yurii N; Kolchinskiy, V A; Kamenev, O T; Petrov, Yu S

2013-02-28T23:59:59.000Z

432

Double-Trace Deformations, Mixed Boundary Conditions and Functional Determinants in AdS/CFT  

E-Print Network (OSTI)

According to the AdS/CFT dictionary, perturbing the large N boundary theory by a relevant double-trace deformation of the form f O^2 corresponds in the bulk to imposing ``mixed'' boundary conditions for the field dual to O. In this note we address various aspects of this correspondence. The change c_{UV} - c_{IR} of the central charge between the UV ad IR fixed points is known from explicit calculations (hep-th/0210093, hep-th/0212138) to be exactly the same in the bulk and in the boundary theories. By comparing the appropriate bulk and boundary functional determinants, we give a simple ``kinematic'' explanation for this universal agreement. We also clarify the prescription for computing AdS/CFT correlators with Delta_- boundary conditions.

Hartman, T; Hartman, Thomas; Rastelli, Leonardo

2008-01-01T23:59:59.000Z

433

Double-Trace Deformations, Mixed Boundary Conditions and Functional Determinants in AdS/CFT  

E-Print Network (OSTI)

According to the AdS/CFT dictionary, perturbing the large N boundary theory by a relevant double-trace deformation of the form f O^2 corresponds in the bulk to imposing ``mixed'' boundary conditions for the field dual to O. In this note we address various aspects of this correspondence. The change c_{UV} - c_{IR} of the central charge between the UV ad IR fixed points is known from explicit calculations (hep-th/0210093, hep-th/0212138) to be exactly the same in the bulk and in the boundary theories. By comparing the appropriate bulk and boundary functional determinants, we give a simple ``kinematic'' explanation for this universal agreement. We also clarify the prescription for computing AdS/CFT correlators with Delta_- boundary conditions.

Thomas Hartman; Leonardo Rastelli

2006-02-10T23:59:59.000Z

434

Evaluation of the filler effects on fatique cracking and permanent deformation of asphalt concrete mixtures  

E-Print Network (OSTI)

The addition of hydrated lime to asphalt has shown to be beneficial with an improvement in the Theological properties of the binder, as well as resistance to permanent deformation (rutting) and fatigue cracking of asphalt concrete mixtures. The addition of hydrated lime produces a filler effect where the result is a stiffening of the asphalt mixture, thus improving the resistance to permanent deformation. The fatigue characteristics of the asphalt mixtures did not worsen from this stiffening effect, but were either improved or similar. The Superpave Performance Grade was not significantly indicative of the filler effects induced by the hydrated lime. However, evaluation of the physical properties, G*/sin5 and G*sin5 were indicative of significant filler effects induced by the hydrated lime. Creep properties, stiffness and m-value showed no substantial change with the addition of lime. The use of 10 to 20% mass concentration of hydrated lime can effectively improve the rutting resistance of the unaged and aged binder with little practical effect on the low temperature and fatigue properties. The filler effects produced through the addition of hydrated lime to the asphalt yielded asphalt mixtures less susceptible to rutting. In most cases, the fatigue life of the asphalt mixtures improved as well. The reference modulus and creep compliance of the asphalt mixtures with lime had shown to have greater fatigue life. In most cases, Stone Matrix Asphalt (SMA) mixtures with lime showed greater resistance to rutting, as well as greater fatigue life. The filler effects from the hydrated lime, as well as the stone-on-stone contact and stiffening from the mastic (two characteristics of SMA mixtures) improved these properties. The addition of hydrated lime to asphalt improved the G*/sin5 and G*sin8 of the asphalt binders. The use of these asphalt binders in asphalt concrete mixtures increased the resistance to rutting and fatigue life. It is apparent that a correlation exists between the asphalt binder and mixture test results.

Izzo, Richard P

1997-01-01T23:59:59.000Z

435

Effects of deformation on the electronic properties of B-C-N nanotubes  

SciTech Connect

We apply first-principles methods, using density functional theory, to investigate the effects of flattening deformation on the electronic properties of BC{sub 2}N and C-doped BNNTs. Four different types of BC{sub 2}N structures are considered. Two of them are semiconductors, and the radial compression produces a significant reduction of the energy band gap. The other two types of structures are metallic, and the effect of radial compression is quite distinct. For one of them it is found the opening of a small band gap, and for the other one no changes are observed. For C-doped tubes, it is also found that the electronic properties undergo significant modifications when subjected to radial compression. - Graphical Abstract: We apply first-principles methods, using density functional theory, to investigate the effects of flattening deformation on the electronic properties of BC{sub 2}N and C-doped BNNTs. Four different types of BC{sub 2}N structures are considered. Two of them are semiconductors, and the radial compression produces a significant reduction of the energy band gap. The other two types of structures are metallic, and the effect of radial compression is quite distinct. For one of them it is found the opening of a small band gap, and for the other one no changes are observed. For C-doped tubes, it is also found that the electronic properties undergo significant modifications when subjected to radial compression. Highlights: Black-Right-Pointing-Pointer We investigated electronic properties of flattened BC{sub 2}N nanotubes. Black-Right-Pointing-Pointer The electronic states depend strongly on compression. Black-Right-Pointing-Pointer It is studied flattened BN nanotubes doped with a carbon atom. Black-Right-Pointing-Pointer The flattened C-doped structures, presents a significant reduction of the gap.

Azevedo, S., E-mail: sazevedo@fisica.ufpb.br [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58059-900 Joao Pessoa-PB (Brazil); Rosas, A. [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58059-900 Joao Pessoa-PB (Brazil); Machado, M. [Departamento de Fisica, Universidade Federal de Pelotas, Caixa Postal 354, 96010-900 Pelotas-RS (Brazil); Kaschny, J.R. [Instituto Federal da Bahia-Campus Vitoria da Conquista, Av. Amazonas 3150, 45030-220 Vitoria da Conquista-BA (Brazil); Chacham, H. [Departamento de Fisica, ICEX, Universidade Federal de Minas Gerais, Caixa Postal 702, 30123-970 Belo Horizonte-MG (Brazil)

2013-01-15T23:59:59.000Z

436

Automatic Segmentation of Whole Breast Using Atlas Approach and Deformable Image Registration  

SciTech Connect

Purpose: To compare interobserver variations in delineating the whole breast for treatment planning using two contouring methods. Methods and Materials: Autosegmented contours were generated by a deformable image registration-based breast segmentation method (DEF-SEG) by mapping the whole breast clinical target volume (CTVwb) from a template case to a new patient case. Eight breast radiation oncologists modified the autosegmented contours as necessary to achieve a clinically appropriate CTVwb and then recontoured the same case from scratch for comparison. The times to complete each approach, as well as the interobserver variations, were analyzed. The template case was also mapped to 10 breast cancer patients with a body mass index of 19.1-35.9 kg/m{sup 2}. The three-dimensional surface-to-surface distances and volume overlapping analyses were computed to quantify contour variations. Results: The median time to edit the DEF-SEG-generated CTVwb was 12.9 min (range, 3.4-35.9) compared with 18.6 min (range, 8.9-45.2) to contour the CTVwb from scratch (30% faster, p = 0.028). The mean surface-to-surface distance was noticeably reduced from 1.6 mm among the contours generated from scratch to 1.0 mm using the DEF-SEG method (p = 0.047). The deformed contours in 10 patients achieved 94% volume overlap before correction and required editing of 5% (range, 1-10%) of the contoured volume. Conclusion: Significant interobserver variations suggested a lack of consensus regarding the CTVwb, even among breast cancer specialists. Using the DEF-SEG method produced more consistent results and required less time. The DEF-SEG method can be successfully applied to patients with different body mass indexes.

Reed, Valerie K.; Woodward, Wendy A. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Zhang Lifei [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Strom, Eric A.; Perkins, George H.; Tereffe, Welela; Oh, Julia L.; Yu, T. Kuan [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Bedrosian, Isabelle [Department of Surgical Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Whitman, Gary J. [Department of Diagnostic Radiology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Buchholz, Thomas A. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Dong Lei [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)], E-mail: ldong@mdanderson.org

2009-04-01T23:59:59.000Z

437

Localization of deformable tumors from short-arc projections using Bayesian estimation  

Science Conference Proceedings (OSTI)

Purpose: The authors present a stochastic framework for radiotherapy patient positioning directly utilizing radiographic projections. This framework is developed to be robust against anatomical nonrigid deformations and to cope with challenging imaging scenarios, involving only a few cone beam CT projections from short arcs. Methods: Specifically, a Bayesian estimator (BE) is explicitly derived for the given scanning geometry. This estimator is compared to reference methods such as chamfer matching (CM) and the minimization of the median absolute error adapted as tools of robust image processing and statistics. In order to show the performance of the stochastic short-arc patient positioning method, a CIRS IMRT thorax phantom study is presented with movable markers and the utilization of an Elekta Synergy{sup Registered-Sign} XVI system. Furthermore, a clinical prostate CBCT scan of a Varian{sup Registered-Sign} On-Board Imager{sup Registered-Sign} system is utilized to investigate the robustness of the method for large variations of image quality (anterior-posterior vs lateral views). Results: The results show that the BE shifts reduce the initial setup error of up to 3 cm down to 3 mm at maximum for an imaging arc as short as 10 Degree-Sign while CM achieves residual errors of 7 mm at maximum only for arcs longer than 40 Degree-Sign . Furthermore, the BE can compensate robustly for low image qualities using several low quality projections simultaneously. Conclusions: In conclusion, an estimation method for marker-based patient positioning for short imaging arcs is presented and shown to be robust and accurate for deformable anatomies.

Hoegele, W.; Zygmanski, P.; Dobler, B.; Kroiss, M.; Koelbl, O.; Loeschel, R. [Department of Radiation Oncology, Regensburg University Medical Center, 93053 Regensburg (Germany) and Department of Computer Science and Mathematics, University of Applied Sciences, 93053 Regensburg (Germany); Department of Radiation Oncology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115 (United States); Department of Radiation Oncology, Regensburg University Medical Center, 93053 Regensburg (Germany); Department of Radiation Oncology, Hospital of the Sisters of Mercy, 4010 Linz (Austria); Department of Radiation Oncology, Regensburg University Medical Center, 93053 Regensburg (Germany); Department of Computer Science and Mathematics, University of Applied Sciences, 93053 Regensburg (Germany)

2012-12-15T23:59:59.000Z

438

(Anti)de Sitter/Poincare symmetries and representations from Poincare/Galilei through a classical deformation approach  

E-Print Network (OSTI)

A classical deformation procedure, based on universal enveloping algebras, Casimirs and curvatures of symmetrical homogeneous spaces, is applied to several cases of physical relevance. Starting from the (3+1)D Galilei algebra, we describe at the level of representations the process leading to its two physically meaningful deformed neighbours. The Poincare algebra is obtained by introducing a negative curvature in the flat Galilean phase space (or space of worldlines), while keeping a flat spacetime. To be precise, starting from a representation of the Galilei algebra with both Casimirs different from zero, we obtain a representation of the Poincare algebra with both Casimirs necessarily equal to zero. The Poincare angular momentum, Pauli-Lubanski components, position and velocity operators, etc. are expressed in terms of "Galilean" operators through some expressions deforming the proper Galilean ones. Similarly, the Newton-Hooke algebras appear by endowing spacetime with a non-zero curvature, while keeping a flat phase space. The same approach, starting from the (3+1)D Poincare algebra provides representations of the (anti)de Sitter as Poincare deformations.

Francisco J. Herranz; Mariano Santander

2006-12-19T23:59:59.000Z

439

Effect of Forging Strain Rate and Deformation Temperature on the Mechanical Properties of Warm-Worked 304L Stainless Steel  

Science Conference Proceedings (OSTI)

Stainless steel 304L forgings were produced with four different types of production forging equipment ľ hydraulic press, mechanical press, screw press, and high-energy rate forging (HERF). Each machine imparted a different nominal strain rate during the deformation. The final forgings were done at the warm working (low hot working) temperatures of 816 ?C, 843 ?C, and 871 ?C. The objectives of the study were to characterize and understand the effect of industrial strain rates (i.e. processing equipment), and deformation temperature on the mechanical properties for the final component. Some of the components were produced with an anneal prior to the final forging while others were deformed without the anneal. The results indicate that lower strain rates produced lower strength and higher ductility components, but the lower strain rate processes were more sensitive to deformation temperature variation and resulted in more within-part property variation. The highest strain rate process, HERF, resulted in slightly lower yield strength due to internal heating. Lower processing temperatures increased strength, decreased ductility but decreased within-part property variation. The anneal prior to the final forging produced a decrease in strength, a small increase in ductility, and a small decrease of within-part property variation.

Nathan T Switzner

2010-02-01T23:59:59.000Z

440

Free Volume Evolution in Metallic Glasses Subjected to Mechanical Deformation Qi-Kai Li1;2  

E-Print Network (OSTI)

Free Volume Evolution in Metallic Glasses Subjected to Mechanical Deformation Qi-Kai Li1;2 and Mo of Sciences, Beijing 100080, P. R. China We define the Turnbull-Cohen free volume as the critical excess of the Voronoi volume of an atom less its core volume. Using molecular dynamics simulation we calculated the free

Li, Mo

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441

Deformed Woods-Saxon Potential in the Frame of Supersymmetric Quantum Mechanics for Any l-State  

E-Print Network (OSTI)

A novel analytically solvable deformed Woods-Saxon potential is investigated by means of the Supersymmetric Quantum Mechanics. Hamiltonian hierarchy method and the shape invariance property are used in the calculations. The energy levels are obtained for any l-state. The interrelations for some nuclear scattering processes are also discussed

Cuneyt Berkdemir; Ayse Berkdemir; Ramazan Sever

2005-02-15T23:59:59.000Z

442

Kinematic model for postorogenic Basin and Range extension | Open Energy  

Open Energy Info (EERE)

Kinematic model for postorogenic Basin and Range extension Kinematic model for postorogenic Basin and Range extension Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Kinematic model for postorogenic Basin and Range extension Details Activities (1) Areas (1) Regions (0) Abstract: The Raft River extensional shear zone is exposed in the Albion-Raft River-Grouse Creek metamorphic core complex. Several studies of ductile deformation have shown that it accommodated crustal stretching in Tertiary time during late orogenic collapse of the thickened Cordilleran crust. Progressive deformation that results from mixed pure and simple shear produces a complex strain pattern along the shear zone. The authors propose a numerical kinematic model that relates strain variations in the shear zone to the different amounts of extension between the brittlely

443

Mechanical properties and modeling of seal-forming lithologies  

Science Conference Proceedings (OSTI)

The goal of this research is to evaluate the roles of deformation and the occurrence of weak sedimentary lithologies subjected to gravitational loads in shaping conventional and unconventional oil and gas reservoirs. Two sedimentary lithologies that influence the geometries, physical properties, and heterogeneities of oil and gas reservoirs are shale and rocksalt. Both form effect barriers to the flow and communication of petroleum and gas and, in many cases, form the seals to major reservoirs due to their low permeabilities. Both are actively deformed in depositional environments due to their low strengths relative to gravitational loads applied. Thus, the shapes of seal-forming units, and the nature of fractures and faults that may breach them depend upon either the mechanical properties of shale or those of salt, and the loading histories to which they have been subjected. Deformed shales may, in addition, serve as unconventional reservoirs of gas if open fractures within them provide sufficient porosity. The fracture and flow properties of shales are not well constrained, and the authors are currently investigating these properties experimentally. The rheology of rocksalt, on the other hand, is well known and they believe that the time is right to apply the experimentally constrained constitutive relations for rocksalt to deformations in the Earth. Efforts are continuing on modeling fracture anisotropy and the authors have examined simple, two-mica models to evaluate the mechanical interactions they proposed for gneiss and mica-poor schists. Brief summaries of the progress and results to date for (1) the mechanical properties of schist, (2) a two-mica model of fracture anisotropy, (3) deformation of shale, and (4) modeling of salt and shale tectonics of the northern Gulf of Mexico are given in the following sections. 35 refs., 33 figs., 1 tab.

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

1991-03-01T23:59:59.000Z

444

An Investigation of Deformation and Fluid Flow at Subduction Zones Using Newly Developed Instrumentation and Finite Element Modeling  

E-Print Network (OSTI)

due to M7 class offshore earthquakes, Geophysical Researchof the convergent Pacific margin offshore Costa Rica fromin the ODP Leg 170 area offshore Costa Rica, Earth and

LaBonte, Alison L

2007-01-01T23:59:59.000Z

445

An investigation of deformation and fluid flow at subduction zones using newly developed instrumentation and finite element modeling  

E-Print Network (OSTI)

due to M7 class offshore earthquakes, Geophysical Researchof the convergent Pacific margin offshore Costa Rica fromin the ODP Leg 170 area offshore Costa Rica, Earth and

LaBonte, Alison Louise

2007-01-01T23:59:59.000Z

446

Ellipsis 3D: A particle-in-cell finite-element hybrid code for modelling mantle convection and lithospheric deformation  

Science Conference Proceedings (OSTI)

We have extended the two-dimensional geodynamics finite-element code ''Ellipsis'' to three-dimensions. Ellipsis uses a hybrid particle in a cell scheme, which combines a fixed mesh of computational points and a dense arrangement of mobile material points. ... Keywords: Finite-element, Lithosphere, Mantle convection, Mixed scheme, Particle-in-cell

Craig O'Neill; Louis Moresi; Dietmar MŘller; Rich Albert; FrÚdÚric Dufour

2006-12-01T23:59:59.000Z

447

An Investigation of Deformation and Fluid Flow at Subduction Zones Using Newly Developed Instrumentation and Finite Element Modeling  

E-Print Network (OSTI)

by offshore hydrologic instrumentation monitoring in thewith continuous GPS instrumentation and seismic networks [Using Newly Developed Instrumentation and Finite Element

LaBonte, Alison L

2007-01-01T23:59:59.000Z

448

An investigation of deformation and fluid flow at subduction zones using newly developed instrumentation and finite element modeling  

E-Print Network (OSTI)

by offshore hydrologic instrumentation monitoring in thewith continuous GPS instrumentation and seismic networks [Using Newly Developed Instrumentation and Finite Element

LaBonte, Alison Louise

2007-01-01T23:59:59.000Z

449

Diagnosis of the Role of Vertical Deformation in a Two-Dimensional Primitive Equation Model of Upper-Level Frontogenesis  

Science Conference Proceedings (OSTI)

Equations are developed for the temporal rates of change of the magnitudes of vector gradients of potential temperature and absolute momentum projected onto vertical planes transverse to straight frontal zones. Subject to restrictions involving ...

Daniel Keyser; Michael J. Pecnick; M. A. Shapiro

1986-04-01T23:59:59.000Z

450

An Investigation of Deformation and Fluid Flow at Subduction Zones Using Newly Developed Instrumentation and Finite Element Modeling  

E-Print Network (OSTI)

isotope studies in the Mojave Desert, California: implications for groundwater chronology and regional seismicity, Chemical Geology,isotope studies in the Mojave Desert, California: implications for groundwater chronology and regional seismicity, Chemical Geology,

LaBonte, Alison L

2007-01-01T23:59:59.000Z

451

An investigation of deformation and fluid flow at subduction zones using newly developed instrumentation and finite element modeling  

E-Print Network (OSTI)

isotope studies in the Mojave Desert, California: implications for groundwater chronology and regional seismicity, Chemical Geology,isotope studies in the Mojave Desert, California: implications for groundwater chronology and regional seismicity, Chemical Geology,

LaBonte, Alison Louise

2007-01-01T23:59:59.000Z

452

Quadrupole shape invariants in the interacting boson model  

E-Print Network (OSTI)

In terms of the Interacting Boson Model, shape invariants for the ground state, formed by quadrupole moments up to sixth order, are studied in the dynamical symmetry limits and, for the first time, over the whole structural range of the IBM-1. The results are related to the effective deformation parameters and their fluctuations in the geometrical model. New signatures that can distinguish vibrator and gamma-soft rotor structures, and one that is related to shape coexistence, are identified.

Werner, V; Von Brentano, P; Casten, R F; Jolos, R V

2000-01-01T23:59:59.000Z

453

Quadrupole shape invariants in the interacting boson model  

E-Print Network (OSTI)

In terms of the Interacting Boson Model, shape invariants for the ground state, formed by quadrupole moments up to sixth order, are studied in the dynamical symmetry limits and, for the first time, over the whole structural range of the IBM-1. The results are related to the effective deformation parameters and their fluctuations in the geometrical model. New signatures that can distinguish vibrator and gamma-soft rotor structures, and one that is related to shape coexistence, are identified.

V. Werner; N. Pietralla; P. von Brentano; R. F. Casten; R. V. Jolos

2000-05-06T23:59:59.000Z

454