A Four-Dimensional Viscoelastic Deformation Model For Long Valley...
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A Multiscale Model for Coupled Heat Conduction and Deformations of Viscoelastic Composites
Khan, Kamran Ahmed
2012-07-16
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 ...
Frankel, Kurt L.
November 2005 Abstract We investigate the effects of viscoelastic (VE) rheologies surrounding a vertically Valley caldera, California: Evidence for viscoelastic rheology. J. Volcanol. Geotherm. Res. 105, 183: andrew.newman@eas.gatech.edu (A.V. Newman). Journal of Volcanology and Geothermal Research 150 (2006) 244
Interaction and Deformation of Viscoelastic Particles. 2. Adhesive Particles
Attard, Phil
Interaction and Deformation of Viscoelastic Particles. 2. Adhesive Particles Phil Attard Ian Wark, 2001. In Final Form: April 30, 2001 Analyzed is the mutual deformation of adhesive particles the particles' adhesion. An analytic
Coupled heat conduction and deformation in a viscoelastic composite cylinder
Shah, Sneha
2010-01-16
Engineering iii ABSTRACT Coupled Heat Conduction and Deformation in a Viscoelastic Composite Cylinder. (August 2008) Sneha B. Shah, B.E., Gujarat University, India Co-Chairs of Advisory Committee: Dr. Hanifah Muliana Dr. Kumbakonam Rajagopal...
Viscoelastic models for explosive binder materials
Bardenhagen, S.G.; Harstad, E.N.; Maudlin, P.J.; Gray, G.T. [Los Alamos National Lab., NM (United States); Foster, J.C. Jr. [Wright Lab., Eglin AFB, FL (United States)
1997-07-01
An improved model of the mechanical properties of the explosive contained in conventional munitions is needed to accurately simulate performance and accident scenarios in weapons storage facilities. A specific class of explosives can he idealized as a mixture of two components: energetic crystals randomly suspended in a polymeric matrix (binder). Strength characteristics of each component material are important in the macroscopic behavior of the composite (explosive). Of interest here is the determination of an appropriate constitutive law for a polyurethane binder material. This paper is a continuation of previous work in modeling polyurethane at moderately high strain rates and for large deformations. Simulation of a large deformation (strains in excess of 100%) Taylor Anvil experiment revealed numerical difficulties which have been addressed. Additional experimental data have been obtained including improved resolution Taylor Anvil data, and stress relaxation data at various strain rates. A thorough evaluation of the candidate viscoelastic constitutive model is made and possible improvements discussed.
Non-linear viscoelastic deformation of polymeric solutions
Sanchez Reyes, Javier
2000-01-01
The dynamics of entangled polymeric solutions were studied using drag of borosilicate discs and conventional shear rheometry devices in order to understand the effect of deformation on the relaxation process and the possible ...
Viscoelastic damage modeling of sinkhole formation Eyal Shalev*, Vladimir Lyakhovsky
Lyakhovsky, Vladimir
Viscoelastic damage modeling of sinkhole formation Eyal Shalev*, Vladimir Lyakhovsky Geological 2012 Keywords: Sinkholes Damage Viscoelasticity Modeling a b s t r a c t The sinkholes along the Dead Sea coast are observed in two main sedimentary environments: alluvial fan sinkholes, which usually
Kuravi, Ramachandra Srinivasa Chaitanya
2012-07-16
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...
Modeling of the Aging Viscoelastic Properties of Cement Paste Using Computational Methods
Li, Xiaodan
2012-07-16
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 ...
Kinetic viscoelasticity modeling applied to degradation during carbon–carbon composite processing
Drakonakis, Vasileios M.
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 ...
Modeling magnetosensitive ion channels in viscoelastic environment of living cells
Igor Goychuk
2015-10-01
We propose and study a model of hypothetical magnetosensitive ionic channels which are long thought to be a possible candidate to explain the influence of weak magnetic fields on living organisms ranging from magnetotactic bacteria to fishes, birds, rats, bats and other mammals including humans. The core of the model is provided by a short chain of magnetosomes serving as a sensor which is coupled by elastic linkers to the gating elements of ion channels forming a small cluster in the cell membrane. The magnetic sensor is fixed by one end on cytoskeleton elements attached to the membrane and is exposed to viscoelastic cytosol. Its free end can reorient stochastically and subdiffusively in viscoelastic cytosol responding to external magnetic field changes and open the gates of coupled ion channels. The sensor dynamics is generally bistable due to bistability of the gates which can be in two states with probabilities which depend on the sensor orientation. For realistic parameters, it is shown that this model channel can operate in the magnetic field of Earth for a small number (5 to 7) of single-domain magnetosomes constituting the sensor rod each of which has a typical size found in magnetotactic bacteria and other organisms, or even just one sufficiently large nanoparticle of a characteristic size also found in nature. It is shown that due to viscoelasticity of medium the bistable gating dynamics generally exhibits power law and stretched exponential distributions of the residence times of the channels in their open and closed states. This provides a generic physical mechanism for explanation of the origin of such anomalous kinetics for other ionic channels whose sensors move in viscoelastic environment provided by either cytosol or biological membrane, in a quite general context, beyond the fascinating hypothesis of magnetosensitive ionic channels we explore.
Hanyk, Ladislav
The Aim effective evaluation of viscoelastic responses of arbitrarily stratified Earth models to surface loading Physical Model Maxwell viscoelastic prestressed selfgravitating sphere, compressible invoked [Press et al., 1996] #15; taking into account the block diagonal structure of P andQ desirable
Cerveny, Vlastislav
The Aim effective evaluation of viscoelastic responses of arbitrarily stratified Earth models to surface loading Physical Model Maxwell viscoelastic pre-stressed self-gravitating sphere, compressible et al., 1996] ¯ taking into account the block diagonal structure of È and É desirable (see next panel
On models for viscoelastic fluid-like materials that are mechanically incompressible and
Cerveny, Vlastislav
On models for viscoelastic fluid-like materials that are mechanically incompressible and thermally of the full NavierStokesFourier system. J. Math. Fluid Mech., 11:274302, 2009 Mechanically incompressible;Viscoelastic fluids Maxwell model F l lsld µm m Mechanical analogue: Spring energy storage. Dashpot
Protein viscoelastic dynamics: a model system
Craig Fogle; Joseph Rudnick; David Jasnow
2015-02-02
A model system inspired by recent experiments on the dynamics of a folded protein under the influence of a sinusoidal force is investigated and found to replicate many of the response characteristics of such a system. The essence of the model is a strongly over-damped oscillator described by a harmonic restoring force for small displacements that reversibly yields to stress under sufficiently large displacement. This simple dynamical system also reveals unexpectedly rich behavior, exhibiting a series of dynamical transitions and analogies with equilibrium thermodynamic phase transitions. The effects of noise and of inertia are briefly considered and described.
An approximate model for the adhesive contact of rough viscoelastic surfaces
Guillaume Haiat; Etienne Barthel
2007-09-05
Surface roughness is known to easily suppress the adhesion of elastic surfaces. Here a simple model for the contact of \\emph{viscoelastic} rough surfaces with significant levels of adhesion is presented. This approach is derived from our previous model [E. Barthel and G. Haiat {\\em Langmuir}, 18 9362 2002] for the adhesive contact of viscoelastic spheres. For simplicity a simple loading/unloading history (infinitely fast loading and constant pull-out velocity) is assumed. The model provides approximate analytical expressions for the asperity response and exhibits the full viscoelastic adhesive contact phenomenology such as stress relaxation inside the contact zone and creep at the contact edges. Combining this model with a Greenwood-Williamson statistical modeling of rough surfaces, we propose a quantitative assessment of the adhesion to rough viscoelastic surfaces. We show that moderate viscoelasticity efficiently restores adhesion on rough surfaces over a wide dynamic range.
Finite Element Modeling of Drilling Using DEFORM
Gardner, Joel D.; Dornfeld, David
2006-01-01
Vijayaraghavan, A. (2005), “Drilling of Fiber- ReinforcedFINITE ELEMENT MODELING OF DRILLING USING DEFORM J. Gardner,of Comprehensive Drilling Simulation Tool” ABSTRACT DEFORM-
MECHANICAL MODELS FOR INTERSEISMIC DEFORMATION IN
Kanda, Ravi
MECHANICAL MODELS FOR INTERSEISMIC DEFORMATION IN SUBDUCTION ZONES Thesis by Ravi V. S. Kanda that mechanical coupling on such asperities alone is sufficient to explain currently available geodetic
Karra, Satish
2009-05-15
[35] developed a stability analysis for the ax- isymmetric Rayleigh instability as well as the non-axisymmetric whipping instability in Newtonian fluids. According to them, the Rayleigh instability due to electrical forces is equivalent to the surface... for viscoelasticity between the beads. . . . . . . . 19 7 Typical result for the discrete particle model showing the bending loop in the jet. Top view shows that the envelope of the jet trajectory is a cone. The number of beads for this simulation N = 100 and non...
Freed, Alan D.; Einstein, Daniel R.; Carson, James P.; Jacob, Rick E.
2012-03-01
In the first year of this contractual effort a hypo-elastic constitutive model was developed and shown to have great potential in modeling the elastic response of parenchyma. This model resides at the macroscopic level of the continuum. In this, the second year of our support, an isotropic dodecahedron is employed as an alveolar model. This is a microscopic model for parenchyma. A hopeful outcome is that the linkage between these two scales of modeling will be a source of insight and inspiration that will aid us in the final year's activity: creating a viscoelastic model for parenchyma.
Modeling fluid flow in deformation bands with stabilized localization...
Office of Scientific and Technical Information (OSTI)
Modeling fluid flow in deformation bands with stabilized localization mixed finite elements. Citation Details In-Document Search Title: Modeling fluid flow in deformation bands...
Real-time Volumetric Deformable Models for Surgery Simulation using
Real-time Volumetric Deformable Models for Surgery Simulation using Finite Elements volumetric Finite Element models to surgery simulation. In particular it presents three new approaches: Virtual Surgery, Real-Time Deformation, Solid Volumetric Deformable Mod- els, Virtual Reality, Finite
Thermomechanical Constitutive Modeling of Viscoelastic Materials undergoing Degradation
Karra, Satish
2012-07-16
.2) 14 The velocity v, the velocity gradient L and the deformation gradient F R are de ned through v := @ R@t ; L := @v @x ; F R := @ R @X : (2.3) It immediately follows that L = _F RF 1 R : (2.4) We denote the symmetric part of the velocity... gradient by D, i.e., D := 12 L + LT : (2.5) The left and right Cauchy-Green stretch tensors B R and C R are de ned through B R := F RFT R ; C R := F T RF R : (2.6) Let p(t) denote the preferred natural con guration associated with the con gu...
STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS...
Office of Scientific and Technical Information (OSTI)
STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS Anter El-Azab 36 MATERIALS SCIENCE dislocation dynamics; mesoscale deformation of metals; crystal mechanics...
Decoherence of spin-deformed bosonic model
Dehdashti, Sh.; Mahdifar, A.; Bagheri Harouni, M.; Roknizadeh, R.
2013-07-15
The decoherence rate and some parameters affecting it are investigated for the generalized spin-boson model. We consider the spin-bosonic model when the bosonic environment is modeled by the deformed harmonic oscillators. We show that the state of the environment approaches a non-linear coherent state. Then, we obtain the decoherence rate of a two-level system which is in contact with a deformed bosonic environment which is either in thermal equilibrium or in the ground state. By using some recent realization of f-deformed oscillators, we show that some physical parameters strongly affect the decoherence rate of a two-level system. -- Highlights: •Decoherence of the generalized spin-boson model is considered. •In this model the environment consists of f-oscillators. •Via the interaction, the state of the environment approaches non-linear coherent states. •Effective parameters on decoherence are considered.
Viscoelastic{Viscoplastic Damage Model for Asphalt Concrete
Graham, Michael A.
2010-10-12
in experiments, and their model was limited to uniaxial loading. Chehab et al. (2003) developed a continuum viscoelastoplastic model for undamaged asphalt concrete, but its scope was also limited to uniaxial characterization. Uzan (2005) developed a damaged...
Viscoelasticity of stepped interfaces
Demkowicz, Michael J.
Using molecular dynamics modeling, we show that interfaces in sputter deposited Cu-Nb superlattices exhibit time-dependent elasticity, i.e., viscoelasticity, under shear loading. In the high temperature and small strain ...
Modeling the Non-linear Viscoelastic Response of High Temperature Polyimides
Karra, Satish
2010-01-01
A constitutive model is developed to predict the viscoelastic response of polyimide resins that are used in high temperature applications. This model is based on a thermodynamic framework that uses the notion that the `natural configuration' of a body evolves as the body undergoes a process and the evolution is determined by maximizing the rate of entropy production in general and the rate of dissipation within purely mechanical considerations. We constitutively prescribe forms for the specific Helmholtz potential and the rate of dissipation (which is the product of density, temperature and the rate of entropy production), and the model is derived by maximizing the rate of dissipation with the constraint of incompressibility, and the reduced energy dissipation equation is also regarded as a constraint in that it is required to be met in every process that the body undergoes. The efficacy of the model is ascertained by comparing the predictions of the model with the experimental data for PMR-15 and HFPE-II-52 ...
Modeling the Non-linear Viscoelastic Response of High Temperature Polyimides
Satish Karra; K. R. Rajagopal
2010-08-20
A constitutive model is developed to predict the viscoelastic response of polyimide resins that are used in high temperature applications. This model is based on a thermodynamic framework that uses the notion that the `natural configuration' of a body evolves as the body undergoes a process and the evolution is determined by maximizing the rate of entropy production in general and the rate of dissipation within purely mechanical considerations. We constitutively prescribe forms for the specific Helmholtz potential and the rate of dissipation (which is the product of density, temperature and the rate of entropy production), and the model is derived by maximizing the rate of dissipation with the constraint of incompressibility, and the reduced energy dissipation equation is also regarded as a constraint in that it is required to be met in every process that the body undergoes. The efficacy of the model is ascertained by comparing the predictions of the model with the experimental data for PMR-15 and HFPE-II-52 polyimide resins.
STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS...
Office of Scientific and Technical Information (OSTI)
and computational modeling of dislocation dynamics of mesoscale deformation of metal single crystals. Specifically, the work aimed to implement a continuum statistical...
Skuller: A volumetric shape registration algorithm for modeling skull deformities
Plotkin, Joshua B.
Skuller: A volumetric shape registration algorithm for modeling skull deformities Yusuf Sahillioglu online 8 April 2015 Keywords: Volumetric shape registration Deformation High-resolution model a b s t r a c t We present an algorithm for volumetric registration of 3D solid shapes. In comparison
Viscoelastic effects on frequency tuning of a dielectric elastomer membrane resonator
Zhou, Jianyou; Jiang, Liying, E-mail: lyjiang@eng.uwo.ca; Khayat, Roger E. [Department of Mechanical and Materials Engineering, The University of Western Ontario, London, Ontario N6A 5B9 (Canada)
2014-03-28
As a recent application of dielectric elastomers (DEs), DE resonators have become an alternative to conventional silicon-based resonators used in MEMS and have attracted much interest from the research community. However, most existing modeling works for the DE resonators ignore the intrinsic viscoelastic effect of the material that may strongly influence their dynamic performance. Based on the finite-deformation viscoelasticity theory for dielectrics, this paper theoretically examines the in-plane oscillation of a DE membrane resonator to demonstrate how the material viscoelasticity affects the actuation and frequency tuning processes of the resonator. From the simulation results, it is concluded that not only the applied voltage can change the natural frequency of the resonator, but also the inelastic deformation contributes to frequency tuning. Due to the viscoelasticity of the material, the electrical loading rate influences the actuation process of the DE resonator, while it has little effect on the final steady frequency tuned by the prescribed voltage within the safety range. With the consideration of the typical failure modes of the resonator and the evolution process of the material, the tunable frequency range and the safe range of the applied voltage of the DE membrane resonator with different dimension parameters are determined in this work, which are found to be dependent on the electrical loading rate. This work is expected to provide a better understanding on the frequency tuning of viscoelastic DE membrane resonators and a guideline for the design of DE devices.
Deformation during casting of steel: model and material C. Beckermann
Beckermann, Christoph
Deformation during casting of steel: model and material properties C. Monroe C. Beckermann Dimensional differences between a final casting and its design are casting distortions. Distortion is created by the deformation occurring throughout solidification and further cooling during the casting process. Accurate
Viscoelastic behavior of fiber-reinforced composite materials undergoing cure
Wang, Kai
1999-01-01
A viscoelastic material model has been proposed to characterize the curing and thermal effects on the viscoelastic material properties of both the matrix material and the composite lamina. Micromechanics simulations are used to generate...
A Four-Dimensional Viscoelastic Deformation Model For Long Valley Caldera,
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop IncIowa (UtilityMichigan)data bookresult9) Jump to:13:28-07:00EboroNHawaii
M. V. Voinova; M. Rodahl; M. Jonson; B. Kasemo
1998-05-21
We have derived the general solution of a wave equation describing the dynamics of two-layere viscoelastic polymer materials of arbitrary thickness deposited on solid (quartz) surfaces in a fluid environment. Within the Voight model of viscoelastic element, we calculate the acoustic response of the system to an applied shear stress, i.e. we find the shift of the quartz generator resonance frequency and of the dissipation factor, and show that it strongly depends on the viscous loading of the adsorbed layers and on the shear storage and loss moduli of the overlayers. These results can readily be applied to quartz crystal acoustical measurements of the viscoelasticity of polymers, which conserve their shape under the shear deformations and do not flow, and layered structures such as protein films adsorbed from solution onto the surface of self-assembled monolayres.
Relativistic Hartree-Fock-Bogoliubov model for deformed nuclei
Ebran, J.-P.; Khan, E.; Pena Arteaga, D.; Vretenar, D.
2011-06-15
The relativistic Hartree-Fock-Bogoliubov model for axially deformed nuclei (RHFBz) is introduced. The model is based on an effective Lagrangian with density-dependent meson-nucleon couplings in the particle-hole channel, and the central part of the Gogny force is used in the pairing channel. The RHFBz quasiparticle equations are solved by expansion in the basis of a deformed harmonic oscillator. Illustrative RHFBz calculations are performed for carbon, neon, and magnesium isotopes. The effect of explicitly including the pion field is investigated for binding energies, deformation parameters, and charge radii and has an impact on the nuclei's shape.
Viscoelastic effects on electromechanical instabilities in dielectric elastomers
Park, Harold S.
Viscoelastic effects on electromechanical instabilities in dielectric elastomers Harold S. Park on the electromechanical behavior of dielectric elastomers. A dynamic, finite deformation finite element formulation, we evaluate the effects of the shear and bulk relaxation times on the electromechanical instability
Dispersion and attenuation for an acoustic wave equation consistent with viscoelasticity
Andrzej Hanyga
2014-01-30
An acoustic wave equation for pressure accounting for viscoelastic attenuation is derived from viscoelastic equations of motion. It differs significantly from the equations proposed by Szabo. Dispersion and attenuation associated with the viscoelastic wave equation is examined. The theory is applied to three classes of viscoelastic models and to the linear attenuation model.
Coefficient of restitution for viscoelastic disks
Thomas Schwager
2007-01-08
The dissipative collision of two identical viscoelastic disks is studied. By using a known law for the elastic part of the interaction force and the viscoelastic damping model an analytical solution for the coefficient of restitution shall be given. The coefficient of restitution depends significantly on the impact velocity. It approaches one for small velocities and decreases for increasing velocities.
Integrable double deformation of the principal chiral model
Francois Delduc; Marc Magro; Benoit Vicedo
2014-10-29
We define a two-parameter family of integrable deformations of the principal chiral model on an arbitrary compact group. The Yang-Baxter sigma-model and the principal chiral model with a Wess-Zumino term both correspond to limits in which one of the two parameters vanishes.
Diffusion of a fluid through a viscoelastic solid
Satish Karra
2010-12-08
This paper is concerned with the diffusion of a fluid through a viscoelastic solid undergoing large deformations. Using ideas from the classical theory of mixtures and a thermodynamic framework based on the notion of maximization of the rate of entropy production, the constitutive relations for a mixture of a viscoelastic solid and a fluid (specifically Newtonian fluid) are derived. By prescribing forms for the specific Helmholtz potential and the rate of dissipation, we derive the relations for the partial stress in the solid, the partial stress in the fluid, the interaction force between the solid and the fluid, and the evolution equation of the natural configuration of the solid. We also use the assumption that the volume of the mixture is equal to the sum of the volumes of the two constituents in their natural state as a constraint. Results from the developed model are shown to be in good agreement with the experimental data for the diffusion of various solvents through high temperature polyimides that are used in the aircraft industry. The swelling of a viscoelastic solid under the application of an external force is also studied.
Dao, Ming
of single cell mechanics under a variety of well-controlled stress-states. In this paper, we first crit contributions to deformation arising from the bending stiffness of the cell membrane and cytoskeleton. Finite not consid- ered. The in-plane shear modulus of the cell membrane was estimated from this approach to be 2
Fallon, Michael Brooks
2012-11-12
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...
Relativistic viscoelastic fluid mechanics
Masafumi Fukuma; Yuho Sakatani
2011-09-01
A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski spacetime become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.
Physical and Statistical Models in Deformation Geodesy
Lipovsky, Brad
2011-01-01
Pore pressure distributions at logarithmic time intervals (The model geometry of pore pressure di?usion through a faultin the text. . . . . . Pore pressure distributions at
An acoustic wave equation based on viscoelasticity
Andrzej Hanyga
2014-01-30
An acoustic wave equation for pressure accounting for viscoelastic attenuation is derived from viscoelastic equations of motion. It is assumed that the relaxation moduli are completely monotonic. The acoustic equation differs significantly from the equations proposed by Szabo (1994) and in several other papers. Integral representations of dispersion and attenuation are derived. General properties and asymptotic behavior of attenuation and dispersion in the low and high frequency range are studied. The results are compatible with experiments. The relation between the asymptotic properties of attenuation and wavefront singularities is examined. The theory is applied to some classes of viscoelastic models and to the quasi-linear attenuation reported in seismology.
Dynamics and Stability of Rolling Viscoelastic Tires
Potter, Trevor
2013-04-30
Current steady state rolling tire calculations often do not include treads because treads destroy the rotational symmetry of the tire. We describe two methodologies to compute time periodic solutions of a two-dimensional viscoelastic tire with treads: solving a minimization problem and solving a system of equations. We also expand on work by Oden and Lin on free spinning rolling elastic tires in which they disovered a hierachy of N-peak steady state standing wave solutions. In addition to discovering a two-dimensional hierarchy of standing wave solutions that includes their N-peak hiearchy, we consider the eects of viscoelasticity on the standing wave solutions. Finally, a commonplace model of viscoelasticity used in our numerical experiments led to non-physical elastic energy growth for large tire speeds. We show that a viscoelastic model of Govindjee and Reese remedies the problem.
Antilinear deformations of Coxeter groups, an application to Calogero models
Andreas Fring; Monique Smith
2010-04-06
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.
Algebraic constructive quantum field theory: Integrable models and deformation techniques
Gandalf Lechner
2015-03-12
Several related operator-algebraic constructions for quantum field theory models on Minkowski spacetime are reviewed. The common theme of these constructions is that of a Borchers triple, capturing the structure of observables localized in a Rindler wedge. After reviewing the abstract setting, we discuss in this framework i) the construction of free field theories from standard pairs, ii) the inverse scattering construction of integrable QFT models on two-dimensional Minkowski space, and iii) the warped convolution deformation of QFT models in arbitrary dimension, inspired from non-commutative Minkowski space.
INTERACTIVE MODELLING OF MPEG-4 DEFORMABLE HUMAN BODY MODELS
Cordier, Frederic
years, human characters have become more and more important in computer animation, virtual reality that are immediately usable for animation. In doing so, we aim to carry out realistic deformations on the human body that encompasses addition of props, face and body animation, coordination along with stages or virtual environments
Winding vacuum energies in a deformed O(4) sigma model
Vladimir V. Bazhanov; Gleb A. Kotousov; Sergei L. Lukyanov
2014-09-01
We consider the problem of calculating the Casimir energies in the winding sectors of Fateev's SS-model, which is an integrable two-parameter deformation of the O(4) non-linear sigma model in two dimensions. This problem lies beyond the scope of all traditional methods of integrable quantum field theory including the thermodynamic Bethe ansatz and non-linear integral equations. Here we propose a solution based on a remarkable correspondence between classical and quantum integrable systems and express the winding energies in terms of certain solutions of the classical sinh-Gordon equation.
Darabi Konartakhteh, Masoud
2012-10-19
for bituminous materials and asphalt mixes. The developed thermodynamic-based framework is general and can be applied for constitutive modeling of different materials such as bituminous materials, soft materials, polymers, and biomaterials. This framework...
A non-local, ordinary-state-based viscoelasticity model for peridynami...
Office of Scientific and Technical Information (OSTI)
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...
A Micromechanical Model for Viscoelastic-Viscoplastic Analysis of Particle Reinforced Composite
Kim, Jeong Sik
2011-02-22
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...
Non-Linear Drying Diffusion and Viscoelastic Drying Shrinkage Modeling in Hardened Cement Pastes
Leung, Chin K.
2010-07-14
The present research seeks to study the decrease in diffusivity rate as relative humidity (RH) decreases and modeling drying shrinkage of hardened cement paste as a poroviscoelastic respose. Thin cement paste strips of 0.4 and 0.5 w/c at age 3 and 7...
Efficient modelling of particle collisions using a non-linear viscoelastic contact force
Ray, Shouryya; Fröhlich, Jochen
2015-01-01
In this paper the normal collision of spherical particles is investigated. The particle interaction is modelled in a macroscopic way using the Hertzian contact force with additional linear damping. The goal of the work is to develop an efficient approximate solution of sufficient accuracy for this problem which can be used in soft-sphere collision models for Discrete Element Methods and for particle transport in viscous fluids. First, by the choice of appropriate units, the number of governing parameters of the collision process is reduced to one, thus providing a dimensionless parameter that characterizes all such collisions up to dynamic similitude. It is a simple combination of known material parameters as well as initial conditions. A rigorous calculation of the collision time and restitution coefficient from the governing equations, in the form of a series expansion in this parameter is provided. Such a first principles calculation is particularly interesting from a theoretical perspective. Since the gov...
Diffusion of a fluid through a viscoelastic solid
Karra, Satish
2010-01-01
This paper is concerned with the diffusion of a fluid through a viscoelastic solid undergoing large deformations. The constitutive relations for a mixture of a viscoelastic solid and a fluid (specifically Newtonian fluid) are derived using ideas from the classical theory of mixtures and a thermodynamic framework based on the notion of maximization of the rate of entropy production. We prescribe forms for the specific Helmholtz potential and the rate of dissipation and the relations for the partial stress in the solid, the partial stress in the fluid, and the interaction force between the solid and the fluid, and the evolution equation of the natural configuration of the solid are derived. We also use the assumption that the volume of the mixture is equal to the sum of the volumes of the two constituents in their natural state as a constraint. Results from the developed model are shown to be in good agreement with the experimental data for the diffusion of various solvents through high temperature polyimides t...
Efficient modelling of particle collisions using a non-linear viscoelastic contact force
Shouryya Ray; Tobias Kempe; Jochen Fröhlich
2015-06-21
In this paper the normal collision of spherical particles is investigated. The particle interaction is modelled in a macroscopic way using the Hertzian contact force with additional linear damping. The goal of the work is to develop an efficient approximate solution of sufficient accuracy for this problem which can be used in soft-sphere collision models for Discrete Element Methods and for particle transport in viscous fluids. First, by the choice of appropriate units, the number of governing parameters of the collision process is reduced to one, which is a simple combination of known material parameters as well as initial conditions. It provides a dimensionless parameter that characterizes all such collisions up to dynamic similitude. Next, a rigorous calculation of the collision time and restitution coefficient from the governing equations, in the form of a series expansion in this parameter is provided. Such a calculation based on first principles is particularly interesting from a theoretical perspective. Since the governing equations present some technical difficulties, the methods employed are also of interest from the point of view of the analytical technique. Using further approximations, compact expressions for the restitution coefficient and the collision time are then provided. These are used to implement an approximate algebraic rule for computing the desired stiffness and damping in the framework of the adaptive collision model (Kempe & Fr\\"{o}hlich, J. Fluid Mech., 709: 445-489, 2012). Numerical tests with binary as well as multiple particle collisions are reported to illustrate the accuracy of the proposed method and its superiority in terms of numerical efficiency.
Anderson, C.A.
1981-01-01
Six years ago the Reactor Safety Research Division of the Nuclear Regulatory Commission (NRC) approached the Los Alamos National Laboratory to develop a comprehensive concrete structural analysis code to predict the static and dynamic behavior of Prestressed Concrete Reactor Vessels (PCRVs) that serve as the containment structure of a High-Temperature Gas-Cooled Reactor. The PCRV is a complex concrete structure that must be modeled in three dimensions and posseses other complicating features such as a steel liner for the reactor cavity and woven cables embedded vertically in the PCRV and wound circumferentially on the outside of the PCRV. The cables, or tendons, are used for prestressing the reactor vessel. In addition to developing the computational capability to predict inelastic three dimensional concrete structural behavior, the code response was verified against documented experiments on concrete structural behavior. This code development/verification effort is described.
Grant, Martin
Modeling elastic and plastic deformations in nonequilibrium processing using phase field crystals K November 2004) A continuum field theory approach is presented for modeling elastic and plastic deformation the construction of a phase field model for the dynamics of crystal growth that includes elastic and plastic
Seismic viscoelastic attenuation Submitted to
Cormier, Vernon F.
Seismic viscoelastic attenuation Submitted to: Encyclopedia of Solid Earth Geophysics Harsh Gupta-3046 USA E-mail: vernon.cormier@uconn.edu Tel: 860-486-3547 Fax: 860-486-3346 #12;SEISMIC VISCOELASTIC ATTENUATION Synonyms Seismic intrinsic attenuation Definitions Linear viscoelastic attenuation. The loss
Modeling Of Surface Deformation From Satellite Radar Interferometry...
with ground-based leveling observations. Two main subsidence areas are observed in the geothermal field, with maximum vertical and horizontal deformation rates of up to 30 mm...
Thermodynamics of viscoelastic fluids: the temperature equation.
Wapperom, Peter
Thermodynamics of viscoelastic fluids: the temperature equation. Peter Wapperom Martien A. Hulsen and Hydrodynamics Rotterdamseweg 145 2628 AL Delft (The Netherlands) Abstract From the thermodynamics with internal. The well- known stress differential models that fit into the thermodynamic theory will be treated
Terwilliger, Thomas C., E-mail: terwilliger@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Read, Randy J. [University of Cambridge, Cambridge CB2 0XY (United Kingdom); Adams, Paul D. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Building 64R0121, Berkeley, CA 94720 (United States); Brunger, Axel T. [Stanford University, 318 Campus Drive West, Stanford, CA 94305-5432 (United States); Afonine, Pavel V.; Grosse-Kunstleve, Ralf W. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Building 64R0121, Berkeley, CA 94720 (United States); Hung, Li-Wei [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2012-07-01
A density-based procedure is described for improving a homology model that is locally accurate but differs globally. The model is deformed to match the map and refined, yielding an improved starting point for density modification and further model-building. An approach is presented for addressing the challenge of model rebuilding after molecular replacement in cases where the placed template is very different from the structure to be determined. The approach takes advantage of the observation that a template and target structure may have local structures that can be superimposed much more closely than can their complete structures. A density-guided procedure for deformation of a properly placed template is introduced. A shift in the coordinates of each residue in the structure is calculated based on optimizing the match of model density within a 6 Å radius of the center of that residue with a prime-and-switch electron-density map. The shifts are smoothed and applied to the atoms in each residue, leading to local deformation of the template that improves the match of map and model. The model is then refined to improve the geometry and the fit of model to the structure-factor data. A new map is then calculated and the process is repeated until convergence. The procedure can extend the routine applicability of automated molecular replacement, model building and refinement to search models with over 2 Å r.m.s.d. representing 65–100% of the structure.
Kinematic models of interseismic deformation in Southern California
Meade, Brendan J. (Brendan Joseph), 1975-
2004-01-01
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 ...
WAVE SPEEDS FOR AN ELASTOPLASTIC MODEL FOR TWODIMENSIONAL DEFORMATIONS WITH A NONASSOCIATIVE FLOW of variables, the character istic speeds of plane wave solutions of the system are computed. For both plastic and elastic deformations, there are two nonzero wave speeds, referred to as fast and slow waves. It is shown
Koneru, Saradhi
2011-10-21
description of HMA. This framework has a reasonably general structure within which a host of dissipative processes can be de- scribed. This framework, to model HMA, recognizes the change in the microstructure of the material through the changes...
A framework for comparing geomechanical models of InSAR-measured surface deformation
De Laplante, Neil Edward James
2011-01-01
High-quality Interferometric Synthetic Aperture Radar (InSAR) surface deformation data for field sites around the world has become widely available over the past decade. Geomechanical models based on InSAR data occur ...
Coupled fluid flow and geomechanical deformation modeling Susan E. Minkoff a,*, C. Mike Stoneb,1
Peszynska, Malgorzata
Coupled fluid flow and geomechanical deformation modeling Susan E. Minkoff a,*, C. Mike Stoneb,1 reservoir properties. Pore pressures from flow are used as loads for the geomechanics code
Long, Maureen Devaney
2006-01-01
In this thesis I report the results of several studies of elastic anisotropy and deformation in the Earth's mantle, using shear wave splitting measurements, numerical models of geodynamical processes, and laboratory ...
Graham, Caroline C.
2010-01-01
Acoustic emissions (AE) can provide information relating to the internal state of a deforming rock sample during laboratory testing and have been utilised to quantify damage progression for time-dependent failure modeling. ...
Crystal Plasticity Modeling of Deformation and Creep in Polycrystalline Ti-6242
Ghosh, Somnath
Crystal Plasticity Modeling of Deformation and Creep in Polycrystalline Ti-6242 DHYANJYOTI DEKA computational model based on crystal plasticity for the analysis of two-phase a/b Ti-6242 polycrystalline alloys. A rate-dependent elastic-crystal plas- ticity model is incorporated in this model to accommodate
Analysis of viscoelastic soft dielectric elastomer generators operating in an electrical circuit
Eliana Bortot; Ralf Denzer; Andreas Menzel; Massimiliano Gei
2014-11-13
A predicting model for soft Dielectric Elastomer Generators (DEGs) must consider a realistic model of the electromechanical behaviour of the elastomer filling, the variable capacitor and of the electrical circuit connecting all elements of the device. In this paper such an objective is achieved by proposing a complete framework for reliable simulations of soft energy harvesters. In particular, a simple electrical circuit is realised by connecting the capacitor, stretched periodically by a source of mechanical work, in parallel with a battery through a diode and with an electrical load consuming the energy produced. The electrical model comprises resistances simulating the effect of the electrodes and of the conductivity current invariably present through the dielectric film. As these devices undergo a high number of electro-mechanical loading cycles at large deformation, the time-dependent response of the material must be taken into account as it strongly affects the generator outcome. To this end, the viscoelastic behaviour of the polymer and the possible change of permittivity with strains are analysed carefully by means of a proposed coupled electro-viscoelastic constitutive model, calibrated on experimental data available in the literature for an incompressible polyacrilate elastomer (3M VHB4910). Numerical results showing the importance of time-dependent behaviour on the evaluation of performance of DEGs for different loading conditions, namely equi-biaxial and uniaxial, are reported in the final section.
Deformation of the UI-14at%Nb shape memory alloy: experiments and modeling
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
2010-12-22
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.
Pumping viscoelastic two-fluid media
Hirofumi Wada
2010-04-08
Using a two-fluid model for viscoelastic polymer solutions, we study analytically fluid transport driven by a transverse, small amplitude traveling wave propagation. The pumping flow far from the waving boundary is shown to be strongly wave number and viscosity dependent, in contrast to a viscous Newtonian fluid. We find the two qualitatively different regimes: In one regime relevant to small wave numbers, the fluidic transport is almost the same as the Newtonian case, and uniform viscoelastic constitutive equations provide a good approximation. In the other regime, the pumping is substantially decreased because of the gel-like character. The boundary separating these two regimes is clarified. Our results suggest possible needs of two-fluid descriptions for the transport and locomotion in biological fluids with cilia and flagella.
Modeling the response of HCP polycrystals deforming by slip and twinning using a finite
Zabaras, Nicholas J.
developments in the field of crystal plasticity modeling and evolution of microstructure. For defor- mation that eliminates the need for increasing the number of discrete crystal orientations to account for new for modeling deformation processes. PACS: 61.72.Mm;61.72.-y;81.40.Ef Keywords: Polycrystal plasticity; Texture
A model for aging under deformation field, residual stresses and strains in soft glassy materials
Joshi, Yogesh Moreshwar
A model for aging under deformation field, residual stresses and strains in soft glassy materials Yogesh M. Joshi* A model is proposed that considers aging and rejuvenation in a soft glassy material as, respectively, a decrease and an increase in free energy. The aging term is weighted by an inverse
Numerical Model for the Deformation of Nucleated Cells by Optical Stretchers
Ihab Sraj; Joshua Francois; David W. M. Marr; Charles D. Eggleton
2015-01-15
In this paper, we seek to model the deformation of nucleated cells by single diode-laser bar optical stretchers. We employ a recently developed computational model, the Dynamic Ray-Tracing method, to determine the stress distribution induced by the applied optical forces on a capsule encapsulating a nucleus of different optical properties. These forces are shape dependent and can deform real non-rigid objects; thus resulting in a dynamically changing optical stress distribution with cell and nucleus deformation. Chinese hamster ovary cell is a common biological cell that is of interest to the biomedical community because of their use in recombinant protein therapeutics and is an example of a nucleated cell. To this end, we model chinese hamster ovary cells as two three-dimensional elastic capsules of variable inner capsule size immersed in a fluid where the hydrodynamic forces are calculated using the Immersed Boundary Method. Our results show that the presence of a nucleus has a major effect on the force distribution on the cell surface and the net deformation. Scattering and gradient forces are reported for different nucleus sizes and the effect of nucleus size on the cell deformation is discussed.
Projected shell model study of neutron-rich deformed isotopes of Sr and Zr
Verma, Sonia; Dar, Parvaiz Ahmad; Devi, Rani [Department of Physics and Electronics, University of Jammu, Jammu-180006 (India)
2008-02-15
The projected shell model (PSM) study of {sup 98-102}Sr and {sup 100-104}Zr nuclei is carried out. The reliability of the ground-state wave function is checked by reproducing yrast spectra and electromagnetic properties. The mechanism for the onset of sudden and large deformation at N=60 is worked out. The present piece of research work has unified the two different, or conflicting, early explanations for the onset of deformation at N=60 by the spherical shell model and mean-field theory.
Holmes, Philip
Nonlinear Muscles, Passive Viscoelasticity and Body Taper Conspire To Create Neuromechanical Phase a model of anguilliform (eel-like) swimming in slender fishes. Building on a continuum mechanical to a combination of passive viscoelastic and geometric properties of the body and active muscle properties
Coupled fluid flow and geomechanical deformation modeling Susan E. Minkoff a,*, C. Mike Stoneb,1
Minkoff, Susan E.
Coupled fluid flow and geomechanical deformation modeling Susan E. Minkoff a,*, C. Mike Stoneb,1 reservoir properties. Pore pressures from flow are used as loads for the geomechanics code-505-844-9297. 2 Fax: +1-512-232-2445. www.elsevier.com/locate/jpetscieng Journal of Petroleum Science
Jia, Yan-Bin
IEEE TRANSACTIONS ON ROBOTICS, VOL. 26, NO. 5, OCTOBER 2010 837 Modeling Deformations of General Parametric Shells Grasped by a Robot Hand Jiang Tian and Yan-Bin Jia, Member, IEEE Abstract--The robot hand and normal of the contact area. Design and analysis of a manipulation strategy thus depend on reliable
A computational model for nanoscale adhesion between deformable solids and its application to gecko adhesion Roger A. Sauer 1 Aachen Institute for Advanced Study in Computational Engineering Science (AICES), RWTH Aachen University, Templergaben 55, 52056 Aachen, Germany Published2 in the Journal of Adhesion
Simons, Mark
Some thoughts on the use of InSAR data to constrain models of surface deformation: Noise structure models of surface deformation: Noise structure and data downsampling, Geochem. Geophys. Geosyst., 6, Q of data points. Here we estimate the actual covariance structure of noise in InSAR data. We compare
Modeling the electrical resistivity of deformation processed metal-metal composites
Tian, Liang; Anderson, Iver; Riedemann, Trevor; Russell, Alan
2014-09-01
Deformation processed metal–metal (matrix–reinforcement) composites (DMMCs) are high-strength, high-conductivity in situ composites produced by severe plastic deformation. The electrical resistivity of DMMCs is rarely investigated mechanistically and tends to be slightly higher than the rule-of-mixtures prediction. In this paper, we analyze several possible physical mechanisms (i.e. phonons, interfaces, mutual solution, grain boundaries, dislocations) responsible for the electrical resistivity of DMMC systems and how these mechanisms could be affected by processing conditions (i.e. temperature, deformation processing). As an innovation, we identified and assembled the major scattering mechanisms for specific DMMC systems and modeled their electrical resistivity in combination. From this analysis, it appears that filament coarsening rather than dislocation annihilation is primarily responsible for the resistivity drop observed in these materials after annealing and that grain boundary scattering contributes to the resistivity at least at the same magnitude as does interface scattering.
Neural network modelling of hot deformation of austenite
Cambridge, University of
-manganese steels. 7 #12;Nomenclature R Gas Constant k Boltzman Constant b Burgers vector exp base of natural on chemical composition, microstructure, temperature and strain rate. While many models have been developed database of compositions and meaningful inputs, including composition. The model allows the calculation
Propulsion in a viscoelastic fluid
Eric Lauga
2007-03-21
Flagella beating in complex fluids are significantly influenced by viscoelastic stresses. Relevant examples include the ciliary transport of respiratory airway mucus and the motion of spermatozoa in the mucus-filled female reproductive tract. We consider the simplest model of such propulsion and transport in a complex fluid, a waving sheet of small amplitude free to move in a polymeric fluid with a single relaxation time. We show that, compared to self-propulsion in a Newtonian fluid occurring at a velocity U_N, the sheet swims (or transports fluid) with velocity U / U_N = [1+De^2 (eta_s)/(eta) ]/[1+De^2], where eta_s is the viscosity of the Newtonian solvent, eta is the zero-shear-rate viscosity of the polymeric fluid, and De is the Deborah number for the wave motion, product of the wave frequency by the fluid relaxation time. Similar expressions are derived for the rate of work of the sheet and the mechanical efficiency of the motion. These results are shown to be independent of the particular nonlinear constitutive equations chosen for the fluid, and are valid for both waves of tangential and normal motion. The generalization to more than one relaxation time is also provided. In stark contrast with the Newtonian case, these calculations suggest that transport and locomotion in a non-Newtonian fluid can be conveniently tuned without having to modify the waving gait of the sheet but instead by passively modulating the material properties of the liquid.
THERMOMECHANICS OF PV MODULES INCLUDING THE VISCOELASTICITY OF EVA Ulrich Eitner1,
THERMOMECHANICS 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 in the cell distance is 170µm. Keywords: PV module, Encapsulation, Simulation, Reliability, Mechanics 1
Paulino, Glaucio H.
products obtained through fractional distillation of crude oil or petroleum. Due to its organic nature - Mirza and Witczak [5] refers to them as short term hardening, which occurs during the mix production by the "Global Aging Model" used
Collision of viscoelastic bodies: Rigorous derivation of dissipative force
Denis S. Goldobin; Eugeniy A. Susloparov; Anastasiya V. Pimenova; Nikolai V. Brilliantov
2015-01-13
We report a new theory of dissipative forces acting between colliding viscoelastic bodies. The impact velocity is assumed not to be large, to avoid plastic deformations and fragmentation at the impact. The bodies may be of an arbitrary convex shape and of different materials. We develop a mathematically rigorous perturbation scheme to solve the continuum mechanics equation that deals with both displacement and displacement rate fields and accounts for the dissipation in the bulk of the material. The perturbative solution of this equation allows to go beyond the previously used quasi-static approximation and obtain the dissipative force. This force does not suffer from the physical inconsistencies of the latter approximation and depends on particle deformation and deformation rate.
Wave propagation in anisotropic viscoelasticity
Andrzej Hanyga
2015-07-01
We extend the theory of complete Bernstein functions to matrix-valued functions and apply it to analyze Green's function of an anisotropic multi-dimension\\-al linear viscoelastic problem. Green's function is given by the superposition of plane waves. Each plane wave is expressed in terms of matrix-valued attenuation and dispersion functions given in terms of a matrix-valued positive semi-definite Radon measure. More explicit formulae are obtained for 3D isotropic viscoelastic Green's functions. As an example of an anisotropic medium the transversely isotropic medium with a constant symmetry axis is considered.
A. M. Gavrilik; Yu. A. Mishchenko
2015-07-23
In the recently proposed two-parameter $\\tilde{\\mu},q$-deformed Bose gas model [Ukr. J. Phys. {\\bf 58}, 1171 (2013), arXiv:1312.1573] aimed to take effectively into account both compositeness of particles and their interaction, the $\\tilde{\\mu},q$-deformed virial expansion of the equation of state (EOS) was obtained. In this paper we further explore the $\\tilde{\\mu},q$-deformation, namely the version of $\\tilde{\\mu},q$-Bose gas model involving deformed distributions and correlation functions. In the model, we explicitly derive the one- and two-particle deformed distribution functions and the intercept of two-particle momentum correlation function. The results are illustrated by plots, and the comparison with known experimental data on two-pion correlation function intercepts extracted in RHIC/STAR experiments is given.
Initial-Value Approach for Viscoelastic Responses of the Earth's
Hanyk, Ladislav
. Viscoelastic models have been used to study the attenuation of the seismic normal modes (Peltier et al. 1981; Yuen & Peltier 1982), earth tides (Lambeck & Nakiboglu 1983; Sabadini et al. 1985), postseismic rebound. (Received July 6, 1997.) 85 #12;86 Chapter 7 Piersanti et al. 1995), postglacial rebound (e.g., Peltier 1974
Initial-Value and Modal Approaches for Transient Viscoelastic Responses
Hanyk, Ladislav
) and Peltier (1974) because of the availability of more precise uplift data with more extensive geographical principle and use of the viscoelastic normal-mode approach (e.g., Peltier 1974; Yuen & Peltier 1982 in the presence of complicated stratified earth models (Han & Wahr 1995; Fang & Hager 1994, 1995; Peltier 1995
InitialValue Approach for Viscoelastic Responses of the Earth's
Hanyk, Ladislav
. Viscoelastic models have been used to study the attenuation of the seismic normal modes (Peltier et al. 1981; Yuen & Peltier 1982), earth tides (Lambeck & Nakiboglu 1983; Sabadini et al. 1985), postseismic rebound. (Received July 6, 1997.) 85 #12; 86 Chapter 7 Piersanti et al. 1995), postglacial rebound (e.g., Peltier
InitialValue and Modal Approaches for Transient Viscoelastic Responses
Hanyk, Ladislav
) and Peltier (1974) because of the availability of more precise uplift data with more extensive geographical principle and use of the viscoelastic normalmode approach (e.g., Peltier 1974; Yuen & Peltier 1982 in the presence of complicated stratified earth models (Han & Wahr 1995; Fang & Hager 1994, 1995; Peltier 1995
Freed, Alan D.; Einstein, Daniel R.
2011-04-14
An isotropic constitutive model for the parenchyma of lung has been derived from the theory of hypo-elasticity. The intent is to use it to represent the mechanical response of this soft tissue in sophisticated, computational, fluid-dynamic models of the lung. This demands that the continuum model be accurate, yet simple and effcient. An objective algorithm for its numeric integration is provided. The response of the model is determined for several boundary-value problems whose experiments are used for material characterization. The effective elastic, bulk, and shear moduli, and Poisson’s ratio, as tangent functions, are also derived. The model is characterized against published experimental data for lung. A bridge between this continuum model and a dodecahedral model of alveolar geometry is investigated, with preliminary findings being reported.
Numerical Model for the Deformation of Nucleated Cells by Optical Stretchers
Sraj, Ihab; Marr, David W M; Eggleton, Charles D
2015-01-01
In this paper, we seek to model the deformation of nucleated cells by single diode-laser bar optical stretchers. We employ a recently developed computational model, the Dynamic Ray-Tracing method, to determine the stress distribution induced by the applied optical forces on a capsule encapsulating a nucleus of different optical properties. These forces are shape dependent and can deform real non-rigid objects; thus resulting in a dynamically changing optical stress distribution with cell and nucleus deformation. Chinese hamster ovary cell is a common biological cell that is of interest to the biomedical community because of their use in recombinant protein therapeutics and is an example of a nucleated cell. To this end, we model chinese hamster ovary cells as two three-dimensional elastic capsules of variable inner capsule size immersed in a fluid where the hydrodynamic forces are calculated using the Immersed Boundary Method. Our results show that the presence of a nucleus has a major effect on the force dis...
Stability of Kink Defects in a Deformed O(3) Linear Sigma Model
A. Alonso Izquierdo; M. A. Gonzalez Leon; J. Mateos Guilarte
2002-04-22
We identify the kinks of a deformed O(3) linear Sigma model as the solutions of a set of first-order systems of equations; the above model is a generalization of the MSTB model with a three-component scalar field. Taking into account certain kink energy sum rules we show that the variety of kinks has the structure of a moduli space that can be compactified in a fairly natural way. The generic kinks, however, are unstable and Morse Theory provides the framework for the analysis of kink stability.
Deformation of layered rocks in the ramp regions of thrust faults: a study with rock models
Chester, Judith Savaso
1985-01-01
wall at an S/Lr of 0. 20. " . . . . . . " "" . . -" . 43 17 Diagram showing the thrust belt terminology used to refer to locations and structures in the models. . . . . . 47 18 Deformation maps of configuration A models layered with lead and a... of configuration A. 65 xi LIST OF FIGURES (continued) Figure Page 25 Plot of slip across the lowest lead or mica unit of the veneer at the apex of the anticline above the ramp (location c) versus S/Lr for models of configurations A and B. 67 26 27 Plot...
Raphael, Elie
Adhesion between a Viscoelastic Material and a Solid Surface F. Saulnier,, T. Ondarc¸uhu,§, A by a weak adhesion, and a solid surface. We reassess the "viscoelastic trumpet" model (de Gennes, P.-G. C. R. We deduce from this integral expression the adhesion energy for different kind of materials: (i) we
Elementary model of severe plastic deformation by KoBo process
Gusak, A.; Storozhuk, N.; Danielewski, M. Korbel, A.; Bochniak, M.
2014-01-21
Self-consistent model of generation, interaction, and annihilation of point defects in the gradient of oscillating stresses is presented. This model describes the recently suggested method of severe plastic deformation by combination of pressure and oscillating rotations of the die along the billet axis (KoBo process). Model provides the existence of distinct zone of reduced viscosity with sharply increased concentration of point defects. This zone provides the high extrusion velocity. Presented model confirms that the Severe Plastic Deformation (SPD) in KoBo may be treated as non-equilibrium phase transition of abrupt drop of viscosity in rather well defined spatial zone. In this very zone, an intensive lateral rotational movement proceeds together with generation of point defects which in self-organized manner make rotation possible by the decrease of viscosity. The special properties of material under KoBo version of SPD can be described without using the concepts of nonequilibrium grain boundaries, ballistic jumps and amorphization. The model can be extended to include different SPD processes.
Getting drowned in a swirl: deformable bead-spring model microswimmers in external flow fields
Niklas Küchler; Hartmut Löwen; Andreas M. Menzel
2015-10-08
Deformability is a central feature of many types of microswimmers, e.g. for artificially generated self-propelled droplets. Here, we analyze deformable bead-spring microswimmers in an externally imposed solvent flow field as simple theoretical model systems. We focus on their behavior in a circular swirl flow in two spatial dimensions. Linear (straight) two-bead swimmers are found to circle around the swirl with a slight drift to the outside with increasing activity. In contrast to that, we observe for triangular three-bead or square-like four-bead swimmers a tendency of being drawn into the swirl and finally getting drowned, although a radial inward component is absent in the flow field. During one cycle around the swirl, the self-propulsion direction of an active triangular or square-like swimmer remains almost constant, while their orbits become deformed exhibiting an egg-like shape. Over time, the swirl flow induces slight net rotations of these swimmer types, which leads to net rotations of the egg-shaped orbits. Interestingly, in certain cases, the orbital rotation changes sense when the swimmer approaches the flow singularity. Our predictions can be verified in real-space experiments on artificial microswimmers.
Development of a Two-Phase Model for the Hot Deformation of Highly-Alloyed Aluminum
A. J. Beaudoin; J. A. Dantzig; I. M. Robertson; B. E. Gore; S. F. Harnish; H. A. Padilla
2005-10-31
Conventional processing methods for highly alloyed aluminum consist of ingot casting, followed by hot rolling and thermal treatments. Defects result in lost productivity and wasted energy through the need to remelt and reprocess the material. This research centers on developing a fundamental understanding for deformation of wrought 705X series alloys, a key alloy system used in structural airframe applications. The development of damage at grain boundaries is characterized through a novel test that provides initiation of failure while preserving a controlled deformation response. Data from these mechanical tests are linked to computer simulations of the hot rolling process through a critical measure of damage. Transmission electron microscopy provides fundamental insight into deformation at these high working temperatures, and--in a novel link between microscale and macroscale response--the evolution of microstructure (crystallographic orientation) provides feedback for tuning of friction in the hot rolling process. The key product of this research is a modeling framework for the analysis of industrial hot rolling.
Viscoelastic response of contractile filament bundles
Achim Besser; Julien Colombelli; Ernst H. K. Stelzer; Ulrich S. Schwarz
2011-02-25
The actin cytoskeleton of adherent tissue cells often condenses into filament bundles contracted by myosin motors, so-called stress fibers, which play a crucial role in the mechanical interaction of cells with their environment. Stress fibers are usually attached to their environment at the endpoints, but possibly also along their whole length. We introduce a theoretical model for such contractile filament bundles which combines passive viscoelasticity with active contractility. The model equations are solved analytically for two different types of boundary conditions. A free boundary corresponds to stress fiber contraction dynamics after laser surgery and results in good agreement with experimental data. Imposing cyclic varying boundary forces allows us to calculate the complex modulus of a single stress fiber.
Multi-scale Modeling Approach to Acoustic Emission during Plastic Deformation
Jagadish Kumar; G. Ananthakrishna
2011-02-20
We address the long standing problem of the origin of acoustic emission commonly observed during plastic deformation. We propose a frame-work to deal with the widely separated time scales of collective dislocation dynamics and elastic degrees of freedom to explain the nature of acoustic emission observed during the Portevin-Le Chatelier effect. The Ananthakrishna model is used as it explains most generic features of the phenomenon. Our results show that while acoustic emission bursts correlated with stress drops are well separated for the type C serrations, these bursts merge to form nearly continuous acoustic signals with overriding bursts for the propagating type A bands.
Kinks from Dynamical Systems: Domain Walls in a Deformed O(N) Linear Sigma Model
A. Alonso Izquierdo; M. A. Gonzalez Leon; J. Mateos Guilarte
2000-03-24
It is shown how a integrable mechanical system provides all the localized static solutions of a deformation of the linear O(N)-sigma model in two space-time dimensions. The proof is based on the Hamilton-Jacobi separability of the mechanical analogue system that follows when time-independent field configurations are being considered. In particular, we describe the properties of the different kinds of kinks in such a way that a hierarchical structure of solitary wave manifolds emerges for distinct N.
A Simple Model for the Deformation-Induced Relaxation of Glassy Polymers
S. M. Fielding; R. G. Larson; M. E. Cates
2011-10-18
Glassy polymers show strain hardening: at constant extensional load, their flow first accelerates, then arrests. Recent experiments have found this to be accompanied by a striking and unexplained dip in the segmental relaxation time. Here we explain such behavior by combining a minimal model of flow-induced liquefaction of a glass, with a description of the stress carried by strained polymers, creating a non-factorable interplay between aging and strain-induced rejuvenation. Under constant load, liquefaction of segmental motion permits strong flow that creates polymer-borne stress. This slows the deformation enough for the segmental modes to re-vitrify, causing strain hardening.
Deformed Hamilton-Jacobi Method in Covariant Quantum Gravity Effective Models
Mu Benrong; Peng Wang; Haitang Yang
2014-08-21
We first briefly revisit the original Hamilton-Jacobi method and show that the Hamilton-Jacobi equation for the action $I$ of tunnelings of a fermionic particle from a charged black hole can be written in the same form as that of a scalar particle. For the low energy quantum gravity effective models which respect covariance of the curved spacetime, we derive the deformed model-independent KG/Dirac and Hamilton-Jacobi equations using the methods of effective field theory. We then find that, to all orders of the effective theories, the deformed Hamilton-Jacobi equations can be obtained from the original ones by simply replacing the mass of emitted particles $m$ with a parameter $m_{eff}$ that includes all the quantum gravity corrections. Therefore, in this scenario, there will be no corrections to the Hawking temperature of a black hole from the quantum gravity effects if its original Hawking temperature is independent of the mass of emitted particles. As a consequence, our results show that breaking covariance in quantum gravity effective models is a key for a black hole to have the remnant left in the evaporation.
A voxel-based finite element model for the prediction of bladder deformation
Chai Xiangfei; Herk, Marcel van; Hulshof, Maarten C. C. M.; Bel, Arjan [Radiation Oncology Department, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam (Netherlands); Radiation Oncology Department, Netherlands Cancer Institute, 1066 CX Amsterdam (Netherlands); Radiation Oncology Department, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam (Netherlands)
2012-01-15
Purpose: A finite element (FE) bladder model was previously developed to predict bladder deformation caused by bladder filling change. However, two factors prevent a wide application of FE models: (1) the labor required to construct a FE model with high quality mesh and (2) long computation time needed to construct the FE model and solve the FE equations. In this work, we address these issues by constructing a low-resolution voxel-based FE bladder model directly from the binary segmentation images and compare the accuracy and computational efficiency of the voxel-based model used to simulate bladder deformation with those of a classical FE model with a tetrahedral mesh. Methods: For ten healthy volunteers, a series of MRI scans of the pelvic region was recorded at regular intervals of 10 min over 1 h. For this series of scans, the bladder volume gradually increased while rectal volume remained constant. All pelvic structures were defined from a reference image for each volunteer, including bladder wall, small bowel, prostate (male), uterus (female), rectum, pelvic bone, spine, and the rest of the body. Four separate FE models were constructed from these structures: one with a tetrahedral mesh (used in previous study), one with a uniform hexahedral mesh, one with a nonuniform hexahedral mesh, and one with a low-resolution nonuniform hexahedral mesh. Appropriate material properties were assigned to all structures and uniform pressure was applied to the inner bladder wall to simulate bladder deformation from urine inflow. Performance of the hexahedral meshes was evaluated against the performance of the standard tetrahedral mesh by comparing the accuracy of bladder shape prediction and computational efficiency. Results: FE model with a hexahedral mesh can be quickly and automatically constructed. No substantial differences were observed between the simulation results of the tetrahedral mesh and hexahedral meshes (<1% difference in mean dice similarity coefficient to manual contours and <0.02 cm difference in mean standard deviation of residual errors). The average equation solving time (without manual intervention) for the first two types of hexahedral meshes increased to 2.3 h and 2.6 h compared to the 1.1 h needed for the tetrahedral mesh, however, the low-resolution nonuniform hexahedral mesh dramatically decreased the equation solving time to 3 min without reducing accuracy. Conclusions: Voxel-based mesh generation allows fast, automatic, and robust creation of finite element bladder models directly from binary segmentation images without user intervention. Even the low-resolution voxel-based hexahedral mesh yields comparable accuracy in bladder shape prediction and more than 20 times faster in computational speed compared to the tetrahedral mesh. This approach makes it more feasible and accessible to apply FE method to model bladder deformation in adaptive radiotherapy.
Deformed Hamilton-Jacobi Method in Covariant Quantum Gravity Effective Models
Benrong, Mu; Yang, Haitang
2014-01-01
We first briefly revisit the original Hamilton-Jacobi method and show that the Hamilton-Jacobi equation for the action $I$ of tunnelings of a fermionic particle from a charged black hole can be written in the same form as that of a scalar particle. For the low energy quantum gravity effective models which respect covariance of the curved spacetime, we derive the deformed model-independent KG/Dirac and Hamilton-Jacobi equations using the methods of effective field theory. We then find that, to all orders of the effective theories, the deformed Hamilton-Jacobi equations can be obtained from the original ones by simply replacing the mass of emitted particles $m$ with a parameter $m_{eff}$ that includes all the quantum gravity corrections. Therefore, in this scenario, there will be no corrections to the Hawking temperature of a black hole from the quantum gravity effects if its original Hawking temperature is independent of the mass of emitted particles. As a consequence, our results show that breaking covariance...
Dynamics of end to end loop formation for an isolated chain in viscoelastic fluid
Rajarshi Chakrabarti
2012-04-04
We theoretically investigate the looping dynamics of a linear polymer immersed in a viscoelastic fluid. The dynamics of the chain is governed by a Rouse model with a fractional memory kernel recently proposed by Weber et al. (S. C. Weber, J. A. Theriot, and A. J. Spakowitz, Phys. Rev. E 82, 011913 (2010)). Using the Wilemski-Fixman (G. Wilemski and M. Fixman, J. Chem. Phys. 60, 866 (1974)) formalism we calculate the looping time for a chain in a viscoelastic fluid where the mean square displacement of the center of mass of the chain scales as t^(1/2). We observe that the looping time is faster for the chain in viscoelastic fluid than for a Rouse chain in Newtonian fluid up to a chain length and above this chain length the trend is reversed. Also no scaling of the looping time with the length of the chain seems to exist for the chain in viscoelastic fluid.
Barham, M; White, D; Steigmann, D; Rudd, R
2009-04-08
Recently a new class of biocompatible elastic polymers loaded with small ferrous particles (magnetoelastomer) was developed at Lawrence Livermore National Laboratory. This new material was formed as a thin film using spin casting. The deformation of this material using a magnetic field has many possible applications to microfluidics. Two methods will be used to calculate the deformation of a circular magneto-elastomeric film subjected to a magnetic field. The first method is an arbitrary Lagrangian-Eulerian (ALE) finite element method (FEM) and the second is based on nonlinear continuum electromagnetism and continuum elasticity in the membrane limit. The comparison of these two methods is used to test/validate the finite element method.
Modeling reactive transport in deformable porous media using the theory of interacting continua.
Turner, Daniel Zack
2012-01-01
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.
Entanglement spectra of the q-deformed Affleck-Kennedy-Lieb-Tasaki model and matrix product states
Raul A. Santos; Francis N. C. Paraan; Vladimir E. Korepin; Andreas Klümper
2012-05-14
We exactly calculate the reduced density matrix of matrix product states (MPS). Our compact result enables one to perform analytic studies of entanglement in MPS. In particular, we consider the MPS ground states of two anisotropic spin chains. One is a q-deformed Affleck-Kennedy-Lieb-Tasaki (AKLT) model and the other is a general spin-1 quantum antiferromagnet with nearest-neighbor interactions. Our analysis shows how anisotropy affects entanglement on different continuous parameter manifolds. We also construct an effective boundary spin model that describes a block of spins in the ground state of the q-deformed AKLT Hamiltonian. The temperature of this effective model is given in terms of the deformation parameter q.
Ray, S Saha; Das, Shantanu
2015-01-01
The article presents the formulation and a new approach to find analytic solutions for fractional continuously variable order dynamic models viz. Fractional continuously variable order mass-spring damper systems. Here, we use the viscoelastic and viscous-viscoelastic dampers for describing the damping nature of the oscillating systems, where the order of fractional derivative varies continuously. Here, we handle the continuous changing nature of fractional order derivative for dynamic systems, which has not been studied yet. By successive iteration method, here we find the solution of fractional continuously variable order mass-spring damper systems, and then give a close form solution. We then present and discuss the solutions obtained in the cases with continuously variable order of damping for this oscillator with graphical plots.
You, Taesun
2013-08-13
-viscoplastic, and thermo-viscodamaged materials, while the aggregate is considered to be a linear, isotropic elastic material. The 2D RVEs were used to study the effects of variation in aggregate shape, distribution, volume fraction, ITZ strength, strain rate... Page Figure IV-19. Damage density distribution of asphalt concrete models with tensile strain rates (50% aggregate volume fraction and T=20 ?C): (a) 10-6/second, (b) 10-5/second, (c) 10-4/second, and (d) 10...
Odegard, Gregory M.
2005-01-01
Properties of Polymeric Materials Through Nanoindentation G. M. Odegard Assistant Professor, Department testing was used to determine the dynamic viscoelastic properties of eight polymer materials, which, therefore, involves the development of accurate constitutive models, material property data
Viscoelastic characterization of collagen-GAG scaffolds
Wong, Matthew Q
2006-01-01
An experimental study was performed to determine whether or not collagen-GAG scaffolds exhibit linear viscoelastic behavior. Tension tests were performed on dry and hydrated engineered collagen-GAG scaffolds in order to ...
Shell model method for Gamow-Teller transitions in heavy, deformed nuclei
Gao Zaochun [Joint Institute for Nuclear Astrophysics and Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); China Institute of Atomic Energy, P.O. Box 275 (18), Beijing 102413 (China); Sun Yang [Joint Institute for Nuclear Astrophysics and Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Chen, Y.-S. [China Institute of Atomic Energy, P.O. Box 275(18), Beijing 102413 (China); Institute of Theoretical Physics, Academia Sinica, Beijing 100080 (China)
2006-11-15
A method for calculation of Gamow-Teller transition rates is developed by using the concept of the Projected Shell Model (PSM). The shell model basis is constructed by superimposing angular-momentum-projected multiquasiparticle configurations, and nuclear wave functions are obtained by diagonalizing the two-body interactions in these projected states. Calculation of transition matrix elements in the PSM framework is discussed in detail, and the effects caused by the Gamow-Teller residual forces and by configuration-mixing are studied. With this method, it may become possible to perform a state-by-state calculation for {beta}-decay and electron-capture rates in heavy, deformed nuclei at finite temperatures. Our first example indicates that, while experimentally known Gamow-Teller transition rates from the ground state of the parent nucleus are reproduced, stronger transitions from some low-lying excited states are predicted to occur, which may considerably enhance the total decay rates once these nuclei are exposed to hot stellar environments.
Genova Barazarte, Ezequiel
2009-05-15
of confining and pore-fluid pressures in a deep-sea chalk showed that the best-fitting asperity-deformation model is sensitive to the effective-pressure model. Measurements of permeability in a Navajo-sandstone specimen as a function of confining pressure were...
Tian, Liang; Russell, Alan; Anderson, Iver
2014-01-03
Deformation processed metal–metal composites (DMMCs) are high-strength, high-electrical conductivity composites developed by severe plastic deformation of two ductile metal phases. The extraordinarily high strength of DMMCs is underestimated using the rule of mixture (or volumetric weighted average) of conventionally work-hardened metals. A dislocation-density-based, strain–gradient–plasticity model is proposed to relate the strain-gradient effect with the geometrically necessary dislocations emanating from the interface to better predict the strength of DMMCs. The model prediction was compared with our experimental findings of Cu–Nb, Cu–Ta, and Al–Ti DMMC systems to verify the applicability of the new model. The results show that this model predicts the strength of DMMCs better than the rule-of-mixture model. The strain-gradient effect, responsible for the exceptionally high strength of heavily cold worked DMMCs, is dominant at large deformation strain since its characteristic microstructure length is comparable with the intrinsic material length.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Tian, Liang; Russell, Alan; Anderson, Iver
2014-01-03
Deformation processed metal–metal composites (DMMCs) are high-strength, high-electrical conductivity composites developed by severe plastic deformation of two ductile metal phases. The extraordinarily high strength of DMMCs is underestimated using the rule of mixture (or volumetric weighted average) of conventionally work-hardened metals. A dislocation-density-based, strain–gradient–plasticity model is proposed to relate the strain-gradient effect with the geometrically necessary dislocations emanating from the interface to better predict the strength of DMMCs. The model prediction was compared with our experimental findings of Cu–Nb, Cu–Ta, and Al–Ti DMMC systems to verify the applicability of the new model. The results show that this model predicts themore »strength of DMMCs better than the rule-of-mixture model. The strain-gradient effect, responsible for the exceptionally high strength of heavily cold worked DMMCs, is dominant at large deformation strain since its characteristic microstructure length is comparable with the intrinsic material length.« less
Squeeze flow of potato starch gel: effect of loading history on visco-elastic properties
Moutushi Dutta Choudhury; Shantanu Das; Sujata Tarafdar
2015-03-25
In this work gelatinized potato starch is shown to retain the memory of past loading history. It exhibits a visco-elastic response which does not depend solely on instantaneous conditions. A simple squeeze flow experiment is performed, where loading is done in two steps with a time lag $\\tau \\sim$ seconds between the steps. The effect on the strain, of varying $\\tau$ is reproduced by a three element visco-elastic solid model. Non-linearity is introduced through a generalized calculus approach by incorporating a non-integer order time derivative in the viscosity equation. A strain hardening proportional to the time lag between the two loading steps is also incorporated. This model reproduces the three salient features observed in the experiment, namely - the memory effect, slight initial oscillations in the strain as well as the long-time solid-like response. Dynamic visco-elasticity of the sample is also reported.
Nonlinear Viscoelastic Biomaterials: Meaningful Characterization and Engineering Inspiration
1/21 Nonlinear Viscoelastic Biomaterials: Meaningful Characterization and Engineering Inspiration Annual Meeting Symposium: Biomaterials: Properties, Variation and Evolution Keywords: biomechanics, mucus techniques for characterization, pedal mucus samples (and biomaterials in general) are viscoelastic
Solving the two-center nuclear shell-model problem with arbitrarily-orientated deformed potentials
Alexis Diaz-Torres
2008-10-02
A general new technique to solve the two-center problem with arbitrarily-orientated deformed realistic potentials is demonstrated, which is based on the powerful potential separable expansion method. As an example, molecular single-particle spectra for $^{12}$C + $^{12}$C $\\to$ $^{24}$Mg are calculated using deformed Woods-Saxon potentials. These clearly show that non-axial symmetric configurations play a crucial role in molecular resonances observed in reaction processes for this system at low energy.
Fluid substitution in rocks saturated with viscoelastic fluids Dina Makarynska1
, Jyoti Behura3 , and Mike Batzle4 ABSTRACT Heavy oils have high densities and extremely high viscosities sands.We model the viscoelastic properties of a heavy- oil-saturated rock sample using CPA and a measured frequency- dependent complex shear modulus of the heavy oil. Comparison of modeled results
Conformal higher-order viscoelastic fluid mechanics
Masafumi Fukuma; Yuho Sakatani
2012-05-28
We present a generally covariant formulation of conformal higher-order viscoelastic fluid mechanics with strain allowed to take arbitrarily large values. We give a general prescription to determine the dynamics of a relativistic viscoelastic fluid in a way consistent with the hypothesis of local thermodynamic equilibrium and the second law of thermodynamics. We then elaborately study the transient time scales at which the strain almost relaxes and becomes proportional to the gradients of velocity. We particularly show that a conformal second-order fluid with all possible parameters in the constitutive equations can be obtained without breaking the hypothesis of local thermodynamic equilibrium, if the conformal fluid is defined as the long time limit of a conformal second-order viscoelastic system. We also discuss how local thermodynamic equilibrium could be understood in the context of the fluid/gravity correspondence.
Implementation of the Log-Conformation Formulation for Two-Dimensional Viscoelastic Flow
Jensen, K E; Okkels, F
2015-01-01
We have implemented the log-conformation method for two-dimensional viscoelastic flow in COMSOL, a commercial high-level finite element package. The code is verified for an Oldroyd-B fluid flowing past a confined cylinder. We are also able to describe the well-known bistability of the viscoelastic flow in a cross-slot geometry for a FENE-CR fluid, and we describe the changes required for performing simulations with the Phan-Thien-Tanner (PTT), Giesekus and FENE-P models. Finally, we calculate the flow of a FENE-CR fluid in a geometry with three in- and outlets. The implementation is included in the supplementary material, and we hope that it can inspire new as well as experienced researchers in the field of differential constitutive equations for viscoelastic flow.
Dietmar Klemm; Alessio Marrani; Nicolò Petri; Camilla Santoli
2015-07-20
We consider a deformation of the well-known stu model of $N=2$, $D=4$ supergravity, characterized by a non-homogeneous special K\\"{a}hler manifold, and by the smallest electric-magnetic duality Lie algebra consistent with its upliftability to five dimensions. We explicitly solve the BPS attractor equations and construct static supersymmetric black holes with radial symmetry, in the context of $\\text{U}(1)$ dyonic Fayet-Iliopoulos gauging, focussing on axion-free solutions. Due to non-homogeneity of the scalar manifold, the model evades the analysis recently given in the literature. The relevant physical properties of the resulting black hole solution are discussed.
Klemm, Dietmar; Petri, Nicolò; Santoli, Camilla
2015-01-01
We consider a deformation of the well-known stu model of $N=2$, $D=4$ supergravity, characterized by a non-homogeneous special K\\"{a}hler manifold, and by the smallest electric-magnetic duality Lie algebra consistent with its upliftability to five dimensions. We explicitly solve the BPS attractor equations and construct static supersymmetric black holes with radial symmetry, in the context of $\\text{U}(1)$ dyonic Fayet-Iliopoulos gauging, focussing on axion-free solutions. Due to non-homogeneity of the scalar manifold, the model evades the analysis recently given in the literature. The relevant physical properties of the resulting black hole solution are discussed.
Devincre, Benoit
Orientation dependence of plastic deformation in nickel-based single crystal superalloys: Discrete of single-crystal nickel-based superalloys is simulated. At 1123 K, two uniaxial tensile loading cases though no cubic slip systems are activated. In the [001] case, the plastic flow is distributed more
W. X. Xue; J. M. Yao; K. Hagino; Z. P. Li; H. Mei; Y. Tanimura
2015-02-18
The impurity effect of hyperon on atomic nuclei has received a renewed interest in nuclear physics since the first experimental observation of appreciable reduction of $E2$ transition strength in low-lying states of hypernucleus $^{7}_\\Lambda$Li. Many more data on low-lying states of $\\Lambda$ hypernuclei will be measured soon for $sd$-shell nuclei, providing good opportunities to study the $\\Lambda$ impurity effect on nuclear low-energy excitations. We carry out a quantitative analysis of $\\Lambda$ hyperon impurity effect on the low-lying states of $sd$-shell nuclei at the beyond-mean-field level based on a relativistic point-coupling energy density functional (EDF), considering that the $\\Lambda$ hyperon is injected into the lowest positive-parity ($\\Lambda_s$) and negative-parity ($\\Lambda_p$) states. We adopt a triaxially deformed relativistic mean-field (RMF) approach for hypernuclei and calculate the $\\Lambda$ binding energies of hypernuclei as well as the potential energy surfaces (PESs) in $(\\beta, \\gamma)$ deformation plane. We also calculate the PESs for the $\\Lambda$ hypernuclei with good quantum numbers using a microscopic particle rotor model (PRM) with the same relativistic EDF. The triaxially deformed RMF approach is further applied in order to determine the parameters of a five-dimensional collective Hamiltonian (5DCH) for the collective excitations of triaxially deformed core nuclei. Taking $^{25,27}_{\\Lambda}$Mg and $^{31}_{\\Lambda}$Si as examples, we analyse the impurity effects of $\\Lambda_s$ and $\\Lambda_p$ on the low-lying states of the core nuclei...
Potyondy, D.O.; Fairhurst, C.E.
1999-07-01
The post-peak load/deformation behavior of cohesive-frictional materials is an integral part of the overall response of a specimen to compressive loading. A more comprehensive understanding of the pre- and post-peak behavior is necessary. Recent developments in numerical modeling that allow study of the overall response of a synthetic material containing discrete heterogeneities and discontinuities both at the micro (particle) scale and at the larger scale of jointed rock masses can greatly aid the interpretation and application of laboratory test results on these materials.
Golden, Peter Joseph
1996-01-01
Traditional methods of viscoelastic material characterization lack the ability to rapidly characterize nonlinear viscoelastic materials. A method of rapidly identifying linear viscoelastic material properties is Dynamic Mechanical Analysis (DMA...
Plane waves in anisotropic viscoelastic media
Andrzej Hanyga
2015-07-13
Two concepts of plane waves in anisotropic viscoelastic media are studied. One of these concepts allows for the use of methods based on the theory of complete Bernstein functions. This allows for a deeper study of frequency-domain asymptotics of the attenuation function and time-domain regularity at the wavefronts. A relation between the direction of the energy flux density and the attenuation vector is examined under much more general assumptions.
Nonlinear viscoelastic materials : bioinspired applications and new characterization measures
Ewoldt, Randy H. (Randy Harold)
2009-01-01
Viscoelastic materials, such as biomaterials and non-Newtonian fluids, typically experience mechanical loading which evokes a nonlinear rheological response. Rheologically complex materials can provide novel functionality ...
Kramer, Sharlotte Lorraine Bolyard; Scherzinger, William M.
2014-09-01
The Virtual Fields Method (VFM) is an inverse method for constitutive model parameter identication that relies on full-eld experimental measurements of displacements. VFM is an alternative to standard approaches that require several experiments of simple geometries to calibrate a constitutive model. VFM is one of several techniques that use full-eld exper- imental data, including Finite Element Method Updating (FEMU) techniques, but VFM is computationally fast, not requiring iterative FEM analyses. This report describes the im- plementation and evaluation of VFM primarily for nite-deformation plasticity constitutive models. VFM was successfully implemented in MATLAB and evaluated using simulated FEM data that included representative experimental noise found in the Digital Image Cor- relation (DIC) optical technique that provides full-eld displacement measurements. VFM was able to identify constitutive model parameters for the BCJ plasticity model even in the presence of simulated DIC noise, demonstrating VFM as a viable alternative inverse method. Further research is required before VFM can be adopted as a standard method for constitu- tive model parameter identication, but this study is a foundation for ongoing research at Sandia for improving constitutive model calibration.
Luscher, Darby J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2014-05-08
We detail a modeling approach to simulate the anisotropic thermal expansion of polycrystalline (1,3,5-triamino-2,4,6-trinitrobenzene) TATB-based explosives that utilizes microstructural information including porosity, crystal aspect ratio, and processing-induced texture. This report, the first in a series, focuses on nonlinear thermal expansion of “neat-pressed” polycrystalline TATB specimens which do not contain any binder; additional complexities related to polymeric binder and irreversible ratcheting behavior are briefly discussed, however detailed investigation of these aspects are deferred to subsequent reports. In this work we have, for the first time, developed a mesoscale continuum model relating the thermal expansion of polycrystal TATB specimens to their microstructural characteristics. A self-consistent homogenization procedure is used to relate macroscopic thermoelastic response to the constitutive behavior of single-crystal TATB. The model includes a representation of grain aspect ratio, porosity, and crystallographic texture attributed to the consolidation process. A quantitative model is proposed to describe the evolution of preferred orientation of graphitic planes in TATB during consolidation and an algorithm constructed to develop a discrete representation of the associated orientation distribution function. Analytical and numerical solutions using this model are shown to produce textures consistent with previous measurements and characterization for isostatic and uniaxial “die-pressed” specimens. Predicted thermal strain versus temperature for textured specimens are shown to be in agreement with corresponding experimental measurements. Using the developed modeling approach, several simulations have been run to investigate the influence of microstructure on macroscopic thermal expansion behavior. Results from these simulations are used to identify qualitative trends. Implications of the identified trends are discussed in the context of thermal deformation of engineered components whose consolidation process is generally more complex than isostatic or die-pressed specimens. Finally, an envisioned application of the modeling approach to simulating thermal expansion of weapon systems and components is outlined along with necessary future work to introduce the effects of binder and ratcheting behavior. Key conclusions from this work include the following. Both porosity and grain aspect ratio have an influence on the thermal expansion of polycrystal TATB considering realistic material variability. Thepreferred orientation of the single crystal TATB [001] poles within a polycrystal gives rise to pronounced anisotropy of the macroscopic thermal expansion. The extent of this preferred orientation depends on the magnitude of deformation, and consequently, is expected to vary spatially throughout manufactured components much like porosity. The modeling approach presented here has utility toward bringing spatially variable microstructural features into macroscale system engineering modelsAbstract Not Provided
Cappa, F.; Rutqvist, J.
2010-06-01
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.
Kinematic models of deformation in Southern California constrained by geologic and geodetic data
Eich, Lori A
2006-01-01
Using a standardized fault geometry based on the Community Block Model, we create two analytic block models of the southern California fault system. We constrain one model with only geodetic data. In the other, we assign ...
Viscoelastic response of Yukawa liquids and P. Hartmann1
Goree, John
interparticle potential. A change from viscous to elastic response is observed with increasing frequency elasticity involves energy storage. Most soft materials are viscoelastic since they exhibit both dissipativeViscoelastic response of Yukawa liquids Z. DonkÃ³,1 J. Goree,2 and P. Hartmann1 1 Research Institute
Deformed shell model results for neutrinoless double beta decay of nuclei in A=60-90 region
R. Sahu; V. K. B. Kota
2015-03-20
Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay of $^{70}$Zn, $^{80}$Se and $^{82}$Se nuclei are calculated within the framework of the deformed shell model based on Hartree-Fock states. For $^{70}$Zn, jj44b interaction in $^{2}p_{3/2}$, $^{1}f_{5/2}$, $^{2}p_{1/2}$ and $^{1}g_{9/2}$ space with $^{56}$Ni as the core is employed. However, for $^{80}$Se and $^{82}$Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for $^{70}$Zn. The above model space was used in many recent shell model and interacting boson model calculations for nuclei in this region. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are $1.1 \\times 10^{26}$ yr, $2.3 \\times 10^{27}$ yr and $2.2 \\times 10^{24}$ yr for $^{70}$Zn, $^{80}$Se and $^{82}$Se, respectively.
Mauroy, Benjamin; Pelca, Dominique; Fausser, Christian; Merckx, Jacques; Mitchell, Barrett R
2015-01-01
Chest physiotherapy is an empirical technique used to help secretions to get out of the lung whenever stagnation occurs. Although commonly used, little is known about the inner mechanisms of chest physiotherapy and controversies about its use are coming out regularly. Thus, a scientific validation of chest physiotherapy is needed to evaluate its effects on secretions. We setup a quasi-static numerical model of chest physiotherapy based on thorax and lung physiology and on their respective biophysics. We modeled the lung with an idealized deformable symmetric bifurcating tree. Bronchi and their inner fluids mechanics are assumed axisymmetric. Static data from the literature is used to build a model for the lung's mechanics. Secretions motion is the consequence of the shear constraints apply by the air flow. The input of the model is the pressure on the chest wall at each time, and the output is the bronchi geometry and air and secretions properties. In the limit of our model, we mimicked manual and mechanical ...
Anupam Gupta; Mauro Sbragaglia
2015-08-01
The effects of viscoelasticity on the dynamics and break-up of fluid threads in microfluidic T-junctions are investigated using numerical simulations of dilute polymer solutions at changing the Capillary number ($\\mbox {Ca}$), i.e. at changing the balance between the viscous forces and the surface tension at the interface, up to $\\mbox{Ca} \\approx 3 \\times 10^{-2}$. A Navier-Stokes (NS) description of the solvent based on the lattice Boltzmann models (LBM) is here coupled to constitutive equations for finite extensible non-linear elastic dumbbells with the closure proposed by Peterlin (FENE-P model). We present the results of three-dimensional simulations in a range of $\\mbox{Ca}$ which is broad enough to characterize all the three characteristic mechanisms of breakup in the confined T-junction, i.e. ${\\it squeezing}$, ${\\it dripping}$ and ${\\it jetting}$ regimes. The various model parameters of the FENE-P constitutive equations, including the polymer relaxation time $\\tau_P$ and the finite extensibility parameter $L^2$, are changed to provide quantitative details on how the dynamics and break-up properties are affected by viscoelasticity. We will analyze cases with ${\\it Droplet ~Viscoelasticity}$ (DV), where viscoelastic properties are confined in the dispersed (d) phase, as well as cases with ${\\it Matrix ~Viscoelasticity}$ (MV), where viscoelastic properties are confined in the continuous (c) phase. Moderate flow-rate ratios $Q \\approx {\\cal O}(1)$ of the two phases are considered in the present study. Overall, we find that the effects are more pronounced in the case with MV, as the flow driving the break-up process upstream of the emerging thread can be sensibly perturbed by the polymer stresses.
Joseph Ben Geloun; Jan Govaerts; M. Norbert Hounkonnou
2006-10-23
Classes of (p,q)-deformations of the Jaynes-Cummings model in the rotating wave approximation are considered. Diagonalization of the Hamiltonian is performed exactly, leading to useful spectral decompositions of a series of relevant operators. The latter include ladder operators acting between adjacent energy eigenstates within two separate infinite discrete towers, except for a singleton state. These ladder operators allow for the construction of (p,q)-deformed vector coherent states. Using (p,q)-arithmetics, explicit and exact solutions to the associated moment problem are displayed, providing new classes of coherent states for such models. Finally, in the limit of decoupled spin sectors, our analysis translates into (p,q)-deformations of the supersymmetric harmonic oscillator, such that the two supersymmetric sectors get intertwined through the action of the ladder operators as well as in the associated coherent states.
A comparison of current work-hardening models used in the analysis of plastic deformations
Vaughn, David Kenneth
1973-01-01
. 63 66 71 VIII THE MROZ MODEL, Basic Concepts Formulation. 77 77 83 IX COMPARISON OF UNIAXIAL AND BIAXIAL TEST DATA WITH MODEL PREDICTIONS Uniaxial Experimental Test 90 90 vi TABLE OF CONTENTS (Continued) CHAPTER PA. GE IX (Continued... in biaxial stress space. 67 Translational effect produced by the mechanical sublayer model. 68 12 Mechanical sublayer model idealization of the uniaxial stress-strain curve. 69 13 Translation of yield surface (Mroz model) 80 14 Compressive uniaxial...
Mesoscopic theory of the viscoelasticity of polymers
S. M. Chitanvis
1999-01-26
We have advanced our previous static theory of polymer entanglement involving an extended Cahn-Hilliard functional, to include time-dependent dynamics. We go beyond the Gaussian approximation, to the one-loop level, to compute the frequency dependent storage and loss moduli of the system. The three parameters in our theory are obtained by fitting to available experimental data on polystyrene melts of various chain lengths. This provides a physical representation of the parameters in terms of the chain length of the system. We discuss the importance of the various terms in our energy functional with respect to their contribution to the viscoelastic response of the polymeric system.
Volk, Brent Louis 1985-
2012-10-16
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...
Zhou, G.; Hallstadius, L.; Helmersson, S.; Massih, A.R.; Schrire, D.; Kaellstroem, R.; Wikmark, G.; Hellwig, C.
2007-07-01
Some basic attributes of light water reactor fuel performance, determined by measurements, are evaluated. In particular, data on fuel volume swelling, cladding creep/growth, fission product gas release and cladding deformation due to pellet-clad mechanical interaction of rods irradiated in power reactors to rod burnups up to about 70 MWd/kgU are presented and appraised. A thermal fuel matrix swelling caused by fission products shows a linear increase in the fuel volume fraction with burnup up to 70 MWd/kgU with a mean rate of 0.76% per 10 MWd/kgU at a best-estimate level. Cladding hoop strain data due to in-reactor creep as a function of burnup from 15 to 70 MWd/kgU for pressurized water reactor (PWR) rods and from 5 to 50 MWd/kgU for boiling water reactor (BWR) rods are presented. The maximum measured cladding creep-down hoop strain in the considered BWR rods is {epsilon}{sub {theta}} {approx_equal} -0.5% and in the PWR rods {epsilon}{sub {theta}} {approx_equal} -1.25%. Rod growth data on BWR and PWR rods as a function of burnup are presented and discussed. Rod internal free volume data, measured and calculated as a function of burnup, are presented. Recent high burnup (52-70 MWd/kgU) fission product gas release data obtained by destructive methods are evaluated with the STAV7 computer code. Finally, slow power ramp experiments conducted at the Studsvik R2 reactor are simulated with the STAV7 code and it is observed that by accounting the contribution of fuel thermal gaseous swelling, the code describes the clad diameter increase due to pellet-clad mechanical interaction under the power bump satisfactorily. (authors)
Nonlinear Dynamics of Coiling in Viscoelastic Jets
Trushant Majmudar; Matthieu Varagnat; William Hartt; Gareth McKinley
2010-12-09
Instabilities in free surface continuous jets of non-Newtonian fluids, although relevant for many industrial processes, remain less well understood in terms of fundamental fluid dynamics. Inviscid, and viscous Newtonian jets have been studied in great detail; buckling instability in viscous jets leads to regular periodic coiling of the jet that exhibits a non-trivial frequency dependence with the height of the fall. Very few experimental or theoretical studies exist for continuous viscoelastic jets beyond the onset of the first instability. Here, we present a systematic study of the effects of viscoelasticity on the dynamics of free surface continuous jets of surfactant solutions that form worm-like micelles. We observe complex nonlinear spatio-temporal dynamics of the jet and uncover a transition from periodic to doubly-periodic or quasi-periodic to a multi-frequency, possibly chaotic dynamics. Beyond this regime, the jet dynamics smoothly crosses over to exhibit the "leaping shampoo effect" or the Kaye effect. This enables us to view seemingly disparate jetting dynamics as one coherent picture of successive instabilities and transitions between them. We identify the relevant scaling variables as the dimensionless height, flow rate, and the elasto-gravity number and present a regime map of the dynamics of the jet in terms of these parameters.
/ free-slip / free-slip Numerical models of slab deformation in the upper mantle
Cerveny, Vlastislav
of the plate. Model: Model domain: Results: Effect of decoupling mechanism 410 km 660 km oceánska doska nadlozná doska Results: Effect of boundary condition Effect of yield stress Plate velocity Kinematic, crust.s 1020 Pa.s 1021 Pa.s Free-slip, crust = 1020 Pas, y = 108 Pa Kinematic, crust = 1020 Pas, y = 109 Pa
A Model for High-Strain-Rate Deformation of Uranium-Niobium Alloys
F.L.Addessio; Q.H.Zuo; T.A.Mason; L.C.Brinson
2003-05-01
A thermodynamic approach is used to develop a framework for modeling uranium-niobium alloys under the conditions of high strain rate. Using this framework, a three-dimensional phenomenological model, which includes nonlinear elasticity (equation of state), phase transformation, crystal reorientation, rate-dependent plasticity, and porosity growth is presented. An implicit numerical technique is used to solve the evolution equations for the material state. Comparisons are made between the model and data for low-strain-rate loading and unloading as well as for heating and cooling experiments. Comparisons of the model and data also are made for low- and high-strain-rate uniaxial stress and uniaxial strain experiments. A uranium-6 weight percent niobium alloy is used in the comparisons of model and experiment.
Ionic content dependence of viscoelasticity of lyotropic chromonic liquid crystal sunset yellow
Shuang Zhou; Adam J. Cervenka; Oleg D. Lavrentovich
2014-10-10
A lyotropic chromonic liquid crystal (LCLC) is an orientationally ordered system made by self-assembled aggregates of charged organic molecules in water, bound by weak non-covalent attractive forces and stabilized by electrostatic repulsions. We determine how the ionic content of the LCLC, namely the presence of mono- and divalent salts and pH enhancing agent, alter the viscoelastic properties of the LCLC. Aqueous solutions of the dye Sunset Yellow with a uniaxial nematic order are used as an example. By applying a magnetic field to impose orientational deformations, we measure the splay $K_1$, twist $K_2$ and bend $K_3$ elastic constants and rotation viscosity $\\gamma_1$ as a function of concentration of additives. The data indicate that the viscoelastic parameters are influenced by ionic content in dramatic and versatile ways. For example, the monovalent salt NaCl decreases $K_3$ and $K_2$ and increases $\\gamma_1$, while an elevated pH decreases all the parameters. We attribute these features to the ion-induced changes in length and flexibility of building units of LCLC, the chromonic aggregates, a property not found in conventional thermotropic and lyotropic liquid crystals formed by covalently bound units of fixed length.
Groleau, Julie; Marecaux, Christophe; Payrard, Natacha; Segaud, Brice; Rochette, Michel; Perrier, Pascal; Payan, Yohan
2008-01-01
A 3D biomechanical finite element model of the face is presented. Muscles are represented by piece-wise uniaxial tension cable elements linking the insertion points. Such insertion points are specific entities differing from nodes of the finite element mesh, which makes possible to change either the mesh or the muscle implementation totally independently of each other. Lip/teeth and upper lip/lower lip contacts are also modeled. Simulations of smiling and of an Orbicularis Oris activation are presented and interpreted. The importance of a proper account of contacts and of an accurate anatomical description is shown
Visco-elastic fluid simulations of coherent structures in strongly coupled dusty plasma medium
Singh Dharodi, Vikram; Kumar Tiwari, Sanat; Das, Amita, E-mail: amita@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
2014-07-15
A generalized hydrodynamic model depicting the behaviour of visco-elastic fluids has often been invoked to explore the behaviour of a strongly coupled dusty plasma medium below their crystallization limit. The model has been successful in describing the collective normal modes of the strongly coupled dusty plasma medium observed experimentally. The paper focuses on the study of nonlinear dynamical characteristic features of this model. Specifically, the evolution of coherent vorticity patches is being investigated here within the framework of this model. A comparison with Newtonian fluids and molecular dynamics simulations treating the dust species interacting through the Yukawa potential has also been presented.
The Asperity-deformation Model Improvements and Its Applications to Velocity Inversion
Bui, Hoa Q.
2010-01-16
-of-nails? (BNM) model. Existing analytic solutions include one that assumes the host rock is infinitely more rigid than the fractures, and one that takes the host-rock compliance into account. Inversion results indicate that although both solutions can fit...
Published in Medical Image Analysis, 1(2):91108, 1996. Deformable Models
Terzopoulos, Demetri
Tracking. 1 Introduction The rapid development and proliferation of medical imaging technologies, with the assistance of computers, clinically useful information about anatomic structures imaged through CT, MR, PET these elements into a coherent and consistent model of the structure. Traditional low-level image processing
MEMS Actuated Deformable Mirror
Papavasiliou, A; Olivier, S; Barbee, T; Walton, C; Cohn, M
2005-11-10
This ongoing work concerns the creation of a deformable mirror by the integration of MEMS actuators with Nanolaminate foils through metal compression boning. These mirrors will use the advantages of these disparate technologies to achieve dense actuation of a high-quality, continuous mirror surface. They will enable advanced adaptive optics systems in large terrestrial telescopes. While MEMS actuators provide very dense actuation with high precision they can not provide large forces typically necessary to deform conventional mirror surfaces. Nanolaminate foils can be fabricated with very high surface quality while their extraordinary mechanical properties enable very thin, flexible foils to survive the rigors of fabrication. Precise metal compression bonding allows the attachment of the fragile MEMS actuators to the thin nanolaminate foils without creating distortions at the bond sites. This paper will describe work in four major areas: (1) modeling and design, (2) bonding development, (3) nanolaminate foil development, (4) producing a prototype. A first-principles analytical model was created and used to determine the design parameters. A method of bonding was determined that is both strong, and minimizes the localized deformation or print through. Work has also been done to produce nanolaminate foils that are sufficiently thin, flexible and flat to be deformed by the MEMS actuators. Finally a prototype was produced by bonding thin, flexible nanolaminate foils to commercially available MEMS actuators.
Viscoelastic transient of confined Red Blood Cells
Gaël Prado; Alexander Farutin; Chaouqi Misbah; Lionel Bureau
2014-09-17
The unique ability of a red blood cell to flow through extremely small microcapillaries depends on the viscoelastic properties of its membrane. Here, we study in vitro the response time upon flow startup exhibited by red blood cells confined into microchannels. We show that the characteristic transient time depends on the imposed flow strength, and that such a dependence gives access to both the effective viscosity and the elastic modulus controlling the temporal response of red cells. A simple theoretical analysis of our experimental data, validated by numerical simulations, further allows us to compute an estimate for the two-dimensional membrane viscosity of red blood cells, $\\eta_{mem}^{2D}\\sim 10^{-7}$ N$\\cdot$s$\\cdot$m$^{-1}$. By comparing our results with those from previous studies, we discuss and clarify the origin of the discrepancies found in the literature regarding the determination of $\\eta_{mem}^{2D}$, and reconcile seemingly conflicting conclusions from previous works.
MODE II FRACTURE BEHAVIOR OF BONDED VISCOELASTIC THERMAL COMPRESSED WOOD
Nairn, John A.
MODE II FRACTURE BEHAVIOR OF BONDED VISCOELASTIC THERMAL COMPRESSED WOOD Andreja Kutnar* Graduate Student Department of Wood Science and Technology Biotechnical Faculty University of Ljubljana 1000 Ljubljana, Slovenia Frederick A. Kamke Professor John A. Nairn Professor Department of Wood Science
Nonlinear viscoelastic dynamics of nano-confined water
Tai-De Li; Elisa Riedo
2007-07-17
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.
Beese, Allison M
2011-01-01
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 ...
Cappa, F.; Rutqvist, J.; Yamamoto, K.
2009-05-15
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.
Dutcher, John
parameters were used to generate a full description of the dynamic viscoelastic behavior of the cells overDynamic viscoelastic behavior of individual Gram-negative bacterial cells Virginia Vadillo) to measure the viscoelastic properties of individual Escherichia coli K12 cells under fully hydrated
Passive Viscoelastic Constrained Layer Damping Application for a Small Aircraft Landing Gear System
Kochersberger, Kevin
Passive Viscoelastic Constrained Layer Damping Application for a Small Aircraft Landing Gear System. Ferris 9/30/2008 Blacksburg, VA Keywords: Viscoelastic, Damping, Loss Factor, Landing Gear, Aircraft #12;Passive Viscoelastic Constrained Layer Damping Application for a Small Aircraft Landing Gear System
Tavgac, Tunc
1968-01-01
CHAPTER I INTRODUCTION Rheology can be described as the science of deformation and flow of matter. A body is said to be deformed when the application of a force system alters the shape or size of the body. It is said to flow if the deformation changes... rheological model. Therefore we can determine whether or not the assumed model really represents the behavior of the vrscoelastic I'luid. The rheological model (Voigt solid) used in this analysis represents a "solid" material which will not sustain...
The deformed exponential functions of two variables
Stankovi?, Miomir S; Rajkovi?, Predrag M
2010-01-01
In the recent development in a various disciplines of physics, it is noted the need for including the deformed versions of the exponential functions. In this paper, we consider the deformations which have two purposes: to have them like special cases, and, even more, to acquit their inauguration from mathematical point of view. Really, we will show interesting differential and difference properties of our deformations which are important in forming and explanation of continuous and discrete models of numerous phenomena.
C. Acerbi; G. Mussardo; A. Valleriani
1996-01-22
The magnetic deformation of the Ising Model, the thermal deformations of both the Tricritical Ising Model and the Tricritical Potts Model are governed by an algebraic structure based on the Dynkin diagram associated to the exceptional algebras $E_n$ (respectively for $n=8,7,6$). We make use of these underlying structures as well as of the discrete symmetries of the models to compute the matrix elements of the stress--energy tensor and its two--point correlation function by means of the spectral representation method.
Dynamics of multiple viscoelastic carbon nanotube based nanocomposites with axial magnetic field
Karli?i?, Danilo; Caji?, Milan; Murmu, Tony; Kozi?, Predrag; Adhikari, Sondipon
2014-06-21
Nanocomposites and magnetic field effects on nanostructures have received great attention in recent years. A large amount of research work was focused on developing the proper theoretical framework for describing many physical effects appearing in structures on nanoscale level. Great step in this direction was successful application of nonlocal continuum field theory of Eringen. In the present paper, the free transverse vibration analysis is carried out for the system composed of multiple single walled carbon nanotubes (MSWCNT) embedded in a polymer matrix and under the influence of an axial magnetic field. Equivalent nonlocal model of MSWCNT is adopted as viscoelastically coupled multi-nanobeam system (MNBS) under the influence of longitudinal magnetic field. Governing equations of motion are derived using the Newton second low and nonlocal Rayleigh beam theory, which take into account small-scale effects, the effect of nanobeam angular acceleration, internal damping and Maxwell relation. Explicit expressions for complex natural frequency are derived based on the method of separation of variables and trigonometric method for the “Clamped-Chain” system. In addition, an analytical method is proposed in order to obtain asymptotic damped natural frequency and the critical damping ratio, which are independent of boundary conditions and a number of nanobeams in MNBS. The validity of obtained results is confirmed by comparing the results obtained for complex frequencies via trigonometric method with the results obtained by using numerical methods. The influence of the longitudinal magnetic field on the free vibration response of viscoelastically coupled MNBS is discussed in detail. In addition, numerical results are presented to point out the effects of the nonlocal parameter, internal damping, and parameters of viscoelastic medium on complex natural frequencies of the system. The results demonstrate the efficiency of the suggested methodology to find the closed form solutions for the free vibration response of multiple nanostructure systems under the influence of magnetic field.
CHAPTER 4: VISCOELASTIC BEHAVIOR OF CARBON NANOTUBE-REINFORCED POLYMERS
Fisher, Frank
123 CHAPTER 4: VISCOELASTIC BEHAVIOR OF CARBON NANOTUBE-REINFORCED POLYMERS Recent experimental results demonstrate that substantial improvements in the elastic properties of a polymer can be attained by using small volume fractions of carbon nanotubes as a reinforcing phase. While these preliminary results
Fast Viscoelastic Behavior with Thin Features Chris Wojtan
Turk, Greg
Fast Viscoelastic Behavior with Thin Features Chris Wojtan Georgia Institute of Technology Greg Turk Georgia Institute of Technology Abstract We introduce a method for efficiently animating a wide simulations of complex elastic and plastic behavior. We signifi- cantly expand the range of physical
Biomaterials 26 (2005) 46954706 Viscoelastic and mechanical behavior of recombinant
Srinivasarao, Mohan
2005-01-01
Biomaterials 26 (2005) 46954706 Viscoelastic and mechanical behavior of recombinant protein of an Ala for the consensus Gly ARTICLE IN PRESS www.elsevier.com/locate/biomaterials 0142-9612/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.biomaterials.2004
Deformable contours Slides from Prof. Kristen Grauman
Kosecka, Jana
;Deformable contours a.k.a. active contours, snakes Given: initial contour (model) near desired object [Snakes contours Given: initial contour (model) near desired object a.k.a. active contours, snakes Figure credit
Khan, Kamran-Ahmed
2009-05-15
solutions within a general displacement based FE structural analyses for small deformations and uncoupled thermo-mechanical problems. A previously developed recursive-iterative algorithm for a stress-dependent hereditary integral model which was developed...
ANALYSES OF DEFORMATION IN VISCOELASTIC SANDWICH COMPOSITES SUBJECT TO MOISTURE DIFFUSION
Joshi, Nikhil P.
2010-01-16
&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Anastasia Muliana Committee Members, Harry Hogan Eyad Masad Head of Department, Dennis L. O?Neal August 2008 Major...% with the increase in moisture concentration. Snead and Palazotto [6] performed an analytical investigation to evaluate the stability characteristics of cylindrical, composite graphite/epoxy (AS/3501-5) laminated panels subjected to axial loads under moist...
Quantifying non-axial deformations in rat myocardium
Aghassibake, Kristina Diane
2005-02-17
Nearly forty years after the introduction of the sliding filament theory, Zahalak expanded Huxley?s cross-bridge model from a uniaxial description of length changes in the fiber direction to a three-dimensional model that accounts for non-axial active..., and is therefore a viscoelastic material. However, in the case of cyclic loading, myocardium behaves elastically when the loading and unloading phases are considered independently; hence, 16 many investigators choose to treat myocardium as a pseudoelastic...
Ehgartner, Brian L.; Sobolik, Steven Ronald; Bean, James E.
2010-07-01
The U.S. Strategic Petroleum Reserve stores crude oil in 62 solution-mined caverns in salt domes located in Texas and Louisiana. Historically, three-dimensional geomechanical simulations of the behavior of the caverns have been performed using a power law creep model. Using this method, and calibrating the creep coefficient to field data such as cavern closure and surface subsidence, has produced varying degrees of agreement with observed phenomena. However, as new salt dome locations are considered for oil storage facilities, pre-construction geomechanical analyses are required that need site-specific parameters developed from laboratory data obtained from core samples. The multi-mechanism deformation (M-D) model is a rigorous mathematical description of both transient and steady-state creep phenomena. Recent enhancements to the numerical integration algorithm within the model have created a more numerically stable implementation of the M-D model. This report presents computational analyses to compare the results of predictions of the geomechanical behavior at the West Hackberry SPR site using both models. The recently-published results using the power law creep model produced excellent agreement with an extensive set of field data. The M-D model results show similar agreement using parameters developed directly from laboratory data. It is also used to predict the behavior for the construction and operation of oil storage caverns at a new site, to identify potential problems before a final cavern layout is designed.
Poludnista Dorsa, Venus: History and context of a deformation belt
Hansen, Vicki
Poludnista Dorsa, Venus: History and context of a deformation belt D. A. Young and V. L. Hansen is combined with altimetry data test models of deformation belt evolution in Venus's lowlands. Poludnista Dorsa, a complex 2000-km-long deformation belt, is highly segmented and broadly time transgressive. Long
Nonlinear viscoelastic characterization of thin films using dynamic mechanical analysis
Payne, Debbie Flowers
1993-01-01
to the modified superposition principle (MSP) and to the Bernstein-Kearsley-Zapas (BKZ) theory. For this comparison, creep and relaxation data were used for all computations. The MSP theory focuses on the separation of creep behavior into time dependent... viscoelastic behavior, and decreases as the applied load increases (12). For the BKZ method, a constitutive method originally developed for an elastic fluid is applied to solids. Smart and Williams show that the MSP method is the simplest to implement...
Deforming convex RP3-structures on 3-orbifolds Deforming convex RP3-structures on 3-orbifolds
Choi, Suhyoung
Deforming convex RP3-structures on 3-orbifolds Deforming convex RP3-structures on 3-orbifolds-structures on 3-orbifolds Outline A RPn-structure (projectively flat structure; real projective structure; projective structure) on an orbifold is a geometric structure on the orbifold modelled on (RPn, PGL(n + 1, R
Cappa, F.
2010-01-01
properties for an anisotropic (ubiquitous joint) elasto?plastic plastic constitutive mechanical model. Properties for an elasto?plastic behavior. The fluid?property module
Cerveny, Vlastislav
Motivation Method Testing Results(1) Instabilities Results(2) Future Viscoelasticity in mantle@karel.troja.mff.cuni.cz] 14th October 2015 Viscoelasticity in mantle convection Charles University in Prague #12;Motivation Method Testing Results(1) Instabilities Results(2) Future Content Motivation Method Testing: Elastic slab
Transmission problems in (thermo-)viscoelasticity with Kelvin-Voigt damping: non-exponential, strong
Racke, Reinhard
Transmission problems in (thermo-)viscoelasticity with Kelvin-Voigt damping: non transmission problems between a (thermo-)viscoelastic system with Kelvin-Voigt damping, and a purely elastic it is coupled through transmission to a purely elastic system. The approach shows the lack of exponential
The matching of 3D Rolie-Poly viscoelastic numerical simulations with experimental polymer melt flow
Jimack, Peter
Kingdom J. Embery and D. Auhl IRC in Polymer Science and Technology, Department of Physics and AstronomyThe matching of 3D Rolie-Poly viscoelastic numerical simulations with experimental polymer melt of commercial viscoelastic polymer melts. Numerical simulation techniques have steadily advanced over the last
Author's personal copy Large deformation and electrochemistry of polyelectrolyte gels
Hong, Wei
Author's personal copy Large deformation and electrochemistry of polyelectrolyte gels Wei Hong and electrochemistry. A specific material model is described, including the effects of stretching the network, mixing
Sandia Energy - Elucidating the Role of Twin Boundaries in Deformation...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Impact Coupled experiment and modeling reveal the dramatic and complex impact of high-density twin boundaries on microstructure evolution and deformation mechanisms Research...
Ganguly, A. E-mail: aganguly@maths.iitkgp.ernet.in; Das, A.
2014-11-15
We consider one-dimensional stationary position-dependent effective mass quantum model and derive a generalized Korteweg-de Vries (KdV) equation in (1+1) dimension through Lax pair formulation, one being the effective mass Schrödinger operator and the other being the time-evolution of wave functions. We obtain an infinite number of conserved quantities for the generated nonlinear equation and explicitly show that the new generalized KdV equation is an integrable system. Inverse scattering transform method is applied to obtain general solution of the nonlinear equation, and then N-soliton solution is derived for reflectionless potentials. Finally, a special choice has been made for the variable mass function to get mass-deformed soliton solution. The influence of position and time-dependence of mass and also of the different representations of kinetic energy operator on the nature of such solitons is investigated in detail. The remarkable features of such solitons are demonstrated in several interesting figures and are contrasted with the conventional KdV-soliton associated with constant-mass quantum model.
A Brief Review of Elasticity and Viscoelasticity
with a brief introduction of some basic terminology and relationships in continuum mechanics, and a review example describing the motion of soil ex- periencing dynamic loading by incorporating a specific form. Key Words: Mathematical modeling, Eulerian and Lagrangian formulations in continuum mechanics
Analysis of Refrigerant Flow and Deformation for a Flexible Short-Tube using a Finite Element Model
O'Neal, D.L.; Bassiouny, R.
2004-01-01
to an increase in the ambien perature above the system design point, a rigi rt-tube can sometimes provide a high enough flow e to flood the compressor with saturated refrigerant the other hand, when the condenser pressur . 1. Schematic of the flexible short...Pa were studied. Four upstream and downstream pressures were applied and the upstream subcooling was held at a constant value of 16.7 ?C. Mass flow rates from the numerical model were compared to available published experimental results. The study showed...
Probing deformed commutators with macroscopic harmonic oscillators
Mateusz Bawaj; Ciro Biancofiore; Michele Bonaldi; Federica Bonfigli; Antonio Borrielli; Giovanni Di Giuseppe; Lorenzo Marconi; Francesco Marino; Riccardo Natali; Antonio Pontin; Giovanni A. Prodi; Enrico Serra; David Vitali; Francesco Marin
2015-08-25
A minimal observable length is a common feature of theories that aim to merge quantum physics and gravity. Quantum mechanically, this concept is associated to a nonzero minimal uncertainty in position measurements, which is encoded in deformed commutation relations. In spite of increasing theoretical interest, the subject suffers from the complete lack of dedicated experiments and bounds to the deformation parameters are roughly extrapolated from indirect measurements. As recently proposed, low-energy mechanical oscillators could allow to reveal the effect of a modified commutator. Here we analyze the free evolution of high quality factor micro- and nano-oscillators, spanning a wide range of masses around the Planck mass $m_{\\mathrm{P}}$ (${\\approx 22\\,\\mu\\mathrm{g}}$), and compare it with a model of deformed dynamics. Previous limits to the parameters quantifying the commutator deformation are substantially lowered.
?-deformation and quantization
Junya Yagi
2014-08-30
We formulate a deformation of Rozansky-Witten theory analogous to the $\\Omega$-deformation. It is applicable when the target space $X$ is hyperk\\"ahler and the spacetime is of the form $\\mathbb{R} \\times \\Sigma$, with $\\Sigma$ being a Riemann surface. In the case that $\\Sigma$ is a disk, the $\\Omega$-deformed Rozansky-Witten theory quantizes a symplectic submanifold of $X$, thereby providing a new perspective on quantization. As applications, we elucidate two phenomena in four-dimensional gauge theory from this point of view. One is a correspondence between the $\\Omega$-deformation and quantization of integrable systems. The other concerns supersymmetric loop operators and quantization of the algebra of holomorphic functions on a hyperk\\"ahler manifold.
Galer, Meghan; Heiner, Jason
2014-01-01
Figure. Appearance of the patient’s affected right arm andnormal left arm. Volume XV, NO . 4 : July 2014 WesternI n E mergency M edicine Arm Weakness and Deformity Meghan
A Model of Viscoelastic Ice-Shelf Flexure
MacAyeal, Douglas R.; Sergienko, Olga V.; Banwell, Alison F.
2015-07-15
-shelf and ice-stream motion and stress fields. Examples of these phenomena27 include tide-driven grounding-line flexure and migration [e.g., Sayag and Worster, 2013, Tsai and28 Gudmundsson, 2015], tidally pulsed grounding line ice velocity variations [e... -shelf flexure that is applicable to circumstances where the114 ratio of vertical to horizontal length scales, H and L, respectively, is small (H/L ? 1), and where115 the vertical displacement (assumed constant through the depth of the ice shelf) due to flexure...
2D Squeezing-flow of a Non-Newtonian Fluid Between Viscoelastic Walls: Numerical Simulations
Talbi, Zouhair
2013-08-31
of the vaginal tissue, vaginal geometry, effects of the neighbouring tissues, and dilution. This thesis presents an engineering approach to help understand the impact of the viscoelastic characteristics of the vaginal tissue on the spreading of different...
A Multi-scale Framework for Thermo-viscoelastic Analysis of Fiber Metal Laminates
Sawant, Sourabh P.
2010-01-14
Fiber Metal Laminates (FML) are hybrid composites with alternate layers of orthotropic fiber reinforced polymers (FRP) and isotropic metal alloys. FML can exhibit a nonlinear thermo-viscoelastic behavior under the influence ...
Biskup, Bruce Allen
1994-01-01
An investigation into the use of dynamic mechanical analysis to characterize the viscoelastic properties of thin film materials is presented. The methodology was investigated using polyethylene films used on high altitude research balloons. Time...
Muddasani, Maithri
2009-05-15
This study presents experimental works and finite element (FE) analyses for understanding nonlinear thermo-viscoelastic behaviors of multilayered (pultruded) composites under tension. Uniaxial isothermal creep tests in tension are conducted...
Effect of Hydrolysis on the Properties of a New Viscoelastic Surfactant-Based Acid
He, Zhenhua
2013-08-07
Viscoelastic surfactants (VES) have been widely used in acidizing and acid fracturing. They are used as diversion agents during matrix acid treatments and leakoff control agents during acid fracturing. At high temperatures, ...
Rothstein, Jonathan
Filament stretching and capillary breakup extensional rheometry measurements of viscoelastic August 2006; final revision received 20 February 2007 Synopsis A filament stretching extensional by a filament stretching rheometer, each of the wormlike micelle solutions demonstrate significant strain
Impact of Fe (III) on the Performance of Viscoelastic Surfactant-Based Acids
Shu, Yi
2013-08-02
Viscoelastic surfactant (VES)-based acid systems have been used successfully in matrix and acid fracturing treatments. However, the existence of Fe (III) as a contaminant in such systems may lead to many problems, due to interactions between VES...
Correlation of mechanical viscoelastic properties to microstructure of equine cortical bone tissue
Ayers, Andrew Kerr
1995-01-01
were taken from equine third metacarpal bones and machined into rectangular slabs approximately 46 mm long, 10 mm wide, and 2 mm thick. After initial testing to determine the linear viscoelastic region of equine compact bone, the specimens were tested...
Guided Wave Propagation in Tubular Section with Multi-Layered Viscoelastic Coating
Kuo, Chi-Wei 1982-
2012-11-16
Three kinds of propagating waves physically admissible in a tubular section are derived to establish their dispersion characteristics in response to the presence of multi-layered viscoelastic coatings. One is the longitudinal wave that propagates...
Dynamics of bead formation, filament thinning and breakup in weakly viscoelastic jets
Ardekani, Arezoo
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 ...
Mechanical modeling of the plastic bonded explosive LX17
Clayton, Kyle Martin
2001-01-01
and time prohibitive to use as a method of characterization, so micromechanical models are developed here. First, the viscoelastic binder and elastic particles are characterized to be used in the developed models. Analytic micromechanics models...
Pre-Stressed Viscoelastic Composites: Effective Incremental Moduli and Band-Gap Tuning
Parnell, William J. [School of Mathematics, Alan Turing Building, University of Manchester, Manchester, M13 9PL (United Kingdom)
2010-09-30
We study viscoelastic wave propagation along pre-stressed nonlinear elastic composite bars. In the pre-stressed state we derive explicit forms for the effective incremental storage and loss moduli with dependence on the pre-stress. We also derive a dispersion relation for the effective wavenumber in the case of arbitrary frequency, hence permitting a study of viscoelastic band-gap tuning via pre-stress.
Nonlinear viscoelastic characterization of AS-3502 graphite/epoxy composite material
Kerstetter, Michael Scott
1980-01-01
NONLINEAR VISCOELASTIC CHARACTERIZATION OF AS-3502 GRAPHITE/EPOXY COMPOSITE MATERIAL A Thesis MICHAEL SCOTT KERSTETTER Submitted to the Graduate College of Texas A8M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1980 Major Subject: Aerospace Engineering NONLINEAR VISCOELASTIC CHARACTERIZATION OF AS-3502 GRAPHITE/EPOXY COMPOSITE MATERIAL A Thesis by MICHAEL SCOTT KERSTETTER Approved as to style and content by: Dr. Kenneth L...
Joakim Arnlind; Harald Grosse
2012-01-13
We recall a construction of non-commutative algebras related to a one-parameter family of (deformed) spheres and tori, and show that in the case of tori, the *-algebras can be completed into C*-algebras isomorphic to the standard non-commutative torus. As the former was constructed in the context of matrix (or fuzzy) geometries, it provides an important link to the framework of non-commutative geometry, and opens up for a concrete way to study deformations of non-commutative tori. Furthermore, we show how the well-known fuzzy sphere and fuzzy torus can be obtained as formal scaling limits of finite-dimensional representations of the deformed algebras, and their projective modules are described together with connections of constant curvature.
Nanolaminate deformable mirrors
Papavasiliou, Alexandros P. (Oakland, CA); Olivier, Scot S. (Santa Cruz, CA)
2009-04-14
A deformable mirror formed out of two layers of a nanolaminate foil attached to a stiff substrate is introduced. Deformation is provided by an electrostatic force between two of the layers. The internal stiffness of the structure allows for high-spatial-frequency shapes. The nanolaminate foil of the present invention allows for a high-quality mirror surface. The device achieves high precision in the vertical direction by using foils with accurately controlled thicknesses, but does not require high precision in the lateral dimensions, allowing such mirrors to be fabricated using crude lithography techniques. Such techniques allow structures up to about the meter scale to be fabricated.
Nanolaminate deformable mirrors
Papavasiliou, Alexandros P.; Olivier, Scot S.
2010-04-06
A deformable mirror formed out of two layers of a nanolaminate foil attached to a stiff substrate is introduced. Deformation is provided by an electrostatic force between two of the layers. The internal stiffness of the structure allows for high-spatial-frequency shapes. The nanolaminate foil of the present invention allows for a high-quality mirror surface. The device achieves high precision in the vertical direction by using foils with accurately controlled thicknesses, but does not require high precision in the lateral dimensions, allowing such mirrors to be fabricated using crude lithography techniques. Such techniques allow structures up to about the meter scale to be fabricated.
A. Besser; U. S. Schwarz
2007-10-24
Biochemistry and mechanics are closely coupled in cell adhesion. At sites of cell-matrix adhesion, mechanical force triggers signaling through the Rho-pathway, which leads to structural reinforcement and increased contractility in the actin cytoskeleton. The resulting force acts back to the sites of adhesion, resulting in a positive feedback loop for mature adhesion. Here we model this biochemical-mechanical feedback loop for the special case when the actin cytoskeleton is organized in stress fibers, which are contractile bundles of actin filaments. Activation of myosin II molecular motors through the Rho-pathway is described by a system of reaction-diffusion equations, which are coupled into a viscoelastic model for a contractile actin bundle. We find strong spatial gradients in the activation of contractility and in the corresponding deformation pattern of the stress fiber, in good agreement with experimental findings.
Seismology of plastic deformation Jero^me Weiss *, Francois Louchet
Weiss, Jérôme
Seismology of plastic deformation Je´ro^me Weiss *, Franc¸ois Louchet Laboratoire de Glaciologie et-free critical picture of dislocational plasticity that challenges the classical continuum models of plasticity rights reserved. Keywords: Acoustic methods; Dislocation dynamics; Plastic deformation; Self
Nayak, R C
2015-01-01
We identify here possible occurrence of large deformations in the neutron- and proton-rich regions of the nuclear chart from extensive predictions of the values of the reduced quadrupole transition probability B-E2 for the transition from the ground state to the first 2+ state and the corresponding excitation energy E2 of even-even nuclei in the recently developed Generalized Differential Equation model exclusively meant for these physical quantities. This is made possible from our analysis of the predicted values of these two physical quantities and the corresponding deformation parameters derived from them such as the quadrupole deformation beta-2, the ratio of beta-2 to the Weisskopf single-particle beta-2 and the intrinsic electric quadruplole moment , calculated for a large number of both known as well as hitherto unknown even-even isotopes of Oxygen to Fermium (Z=8 to 100). Our critical analysis of the resulting data convincingly support possible existence of large collectivity for the nuclides 30,32 Ne...
M. Hassan Farshbaf-Shaker; Christian Heinemann
2015-07-08
In this work we investigate a phase field model for damage processes in two-dimensional viscoelastic media with nonhomogeneous Neumann data describing external boundary forces. In the first part we establish global-in-time existence, uniqueness, a priori estimates and continuous dependence of strong solutions on the data. The main difficulty is caused by the irreversibility of the phase field variable which results in a constrained PDE system. In the last part we consider an optimal control problem where a cost functional penalizes maximal deviations from prescribed damage profiles. The goal is to minimize the cost functional with respect to exterior forces acting on the boundary which play the role of the control variable in the considered model. To this end, we prove existence of minimizers and study a family of "local" approximations via adapted cost functionals.
R. C. Nayak; S. Pattnaik
2015-08-04
We identify here possible occurrence of large deformations in the neutron- and proton-rich regions of the nuclear chart from extensive predictions of the values of the reduced quadrupole transition probability B-E2 for the transition from the ground state to the first 2+ state and the corresponding excitation energy E2 of even-even nuclei in the recently developed Generalized Differential Equation model exclusively meant for these physical quantities. This is made possible from our analysis of the predicted values of these two physical quantities and the corresponding deformation parameters derived from them such as the quadrupole deformation beta-2, the ratio of beta-2 to the Weisskopf single-particle beta-2 and the intrinsic electric quadruplole moment , calculated for a large number of both known as well as hitherto unknown even-even isotopes of Oxygen to Fermium (Z=8 to 100). Our critical analysis of the resulting data convincingly support possible existence of large collectivity for the nuclides 30,32 Ne, 34 Mg, 60 Ti, 42,62,64 Cr, 50,68 Fe, 52,72 Ni, 72,70,96 Kr, 74,76 Sr,78,80,106,108 Zr , 82,84,110,112 Mo, 140 Te,144 Xe, 148 Ba, 122 Ce, 128,156 Nd, 130,132,158,160 Sm and 138,162,164,166 Gd, whose values of beta-2 are found to exceed 0.3 and even 0.4 in some cases. Our findings of large deformations in the exotic neutron-rich regions support the existence of another Island of Inversion in the heavy-mass region possibly caused by breaking of the N=70 sub-shell closure.
Banding in single crystals during plastic deformation
Mahesh, Sivasambu
Banding in single crystals during plastic deformation M. Arul Kumar a Sivasambu Mahesh a,b a. India. Abstract A rigid-plastic rate-independent crystal plasticity model capable of capturing band- ing such as dense dislocation walls. Key words: crystal plasticity, single crystal, macroscopic shear band, regular
Partial Dynamical Symmetry in Deformed Nuclei
A. Leviatan
1996-06-23
We discuss the notion of partial dynamical symmetry in relation to nuclear spectroscopy. Explicit forms of Hamiltonians with partial $SU(3)$ symmetry are presented in the framework of the interacting boson model of nuclei. An analysis of the resulting spectrum and electromagnetic transitions demonstrates the relevance of such partial symmetry to the spectroscopy of axially deformed nuclei.
Loop-deformed Poincaré algebra
Jakub Mielczarek
2013-04-08
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.
Partially segmented deformable mirror
Bliss, Erlan S. (Danville, CA); Smith, James R. (Livermore, CA); Salmon, J. Thaddeus (Livermore, CA); Monjes, Julio A. (San Ramon, CA)
1991-01-01
A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp.
Experimental deformation of muscovite
Mares, Vanadis Marina
1992-01-01
deformed at 45' to (001) exhibit smooth undulatory extinction associated with dislocation glide, with few low-angle kink band boundaries. Basal shear strengths are insensitive to confining pressure between 100 and 400 MPa. Results for samples shortened... and an exponential constant a of 0. 5+0. 2 MPa-1. Samples loaded parallel to the basal plane shorten by the development of sharply defined kink bands. Strengths associated with kink band formation for samples loaded parallel to (001) are higher than those...
${\\cal D}$-deformed harmonic oscillators
F. Bagarello; F. Gargano; D. Volpe
2014-12-30
We analyze systematically several deformations arising from two-dimensional harmonic oscillators which can be described in terms of $\\cal{D}$-pseudo bosons. They all give rise to exactly solvable models, described by non self-adjoint hamiltonians whose eigenvalues and eigenvectors can be found adopting the quite general framework of the so-called $\\cal{D}$-pseudo bosons. In particular, we show that several models previously introduced in the literature perfectly fit into this scheme.
Forward Roll Coating Flows of Viscoelastic G. A. Zevallos1,2, M. S. Carvalho1, M. Pasquali2
Natelson, Douglas
Forward Roll Coating Flows of Viscoelastic Liquids G. A. Zevallos1,2, M. S. Carvalho1, M. Pasquali2, the film splitting flow that occurs in forward roll coating is three-dimensional and results in more is viscoelastic. #12;1 Introduction Roll coating is widely used to apply a thin liquid layer to a continuous
Gupta, Anupam
2015-01-01
Based on mesoscale lattice Boltzmann (LB) numerical simulations, we investigate the effects of viscoelasticity on the break-up of liquid threads in microfluidic cross-junctions, where droplets are formed by focusing a liquid thread of a dispersed (d) phase into another co-flowing continuous (c) immiscible phase. Working at small Capillary numbers, we investigate the effects of non-Newtonian phases in the transition from droplet formation at the cross-junction (DCJ) to droplet formation downstream of the cross-junction (DC) (Liu $\\&$ Zhang, ${\\it Phys. ~Fluids.}$ ${\\bf 23}$, 082101 (2011)). We will analyze cases with ${\\it Droplet ~Viscoelasticity}$ (DV), where viscoelastic properties are confined in the dispersed phase, as well as cases with ${\\it Matrix ~Viscoelasticity}$ (MV), where viscoelastic properties are confined in the continuous phase. Moderate flow-rate ratios $Q \\approx {\\cal O}(1)$ of the two phases are considered in the present study. Overall, we find that the effects are more pronounced in ...
Role of viscoelasticity and non-linear rheology in flows of complex fluids at high deformation rates
Ober, Thomas J. (Thomas Joseph)
2013-01-01
We combine pressure, velocimetry and birefringence measurements to study three phenomena for which the fluid rheology plays a dominant role: 1) shear banding in micellar fluids, 2) extension-dominated flows in microfluidic ...
Electric-magnetic deformations of D=4 gauged supergravities
Inverso, Gianluca
2015-01-01
We discuss duality orbits and symplectic deformations of D=4 gauged supergravity theories, with focus on N$\\ge$2. We provide a general constructive framework for computing symplectic deformations starting from a reference gauging, and apply it to many interesting examples. We prove that no continuous deformations are allowed for Fayet-Iliopoulos gaugings of the N=2 STU model and in particular that any $\\omega$ deformation is classically trivial. We further show that although in the N=6 truncation of SO(8) maximal supergravity the $\\omega$ parameter can be dualized away, in the 'twin' N=2 truncation $\\omega$ is preserved and a second, new deformation appears. We further provide a full classification and appropriate duality orbits of certain N=4 gauged supergravities, including all inequivalent SO(4)$^2$ gaugings and several non-compact forms.
Wide band Fresnel super-resolution applied to capillary break up of viscoelastic fluids
Fiscina, Jorge E; Sattler, Rainer; Wagner, Christian
2013-01-01
We report a technique based on Fresnel diffraction with white illumination that permits the resolution of capillary surface patterns of less than 100 nanometers. We investigate Rayleigh Plateaux like instability on a viscoelastic capillary bridge and show that we can overcome the resolution limit of optical microscopy. The viscoelastic filaments are approximately 20 microns thick at the end of the thinning process when the instability sets in. The wavy distortions grow exponentially in time and the pattern is resolved by an image treatment that is based on an approximation of the measured rising flank of the first Fresnel peak.
Wide band Fresnel super-resolution applied to capillary break up of viscoelastic fluids
Jorge E. Fiscina; Pierre Fromholz; Rainer Sattler; Christian Wagner
2013-10-05
We report a technique based on Fresnel diffraction with white illumination that permits the resolution of capillary surface patterns of less than 100 nanometers. We investigate Rayleigh Plateaux like instability on a viscoelastic capillary bridge and show that we can overcome the resolution limit of optical microscopy. The viscoelastic filaments are approximately 20 microns thick at the end of the thinning process when the instability sets in. The wavy distortions grow exponentially in time and the pattern is resolved by an image treatment that is based on an approximation of the measured rising flank of the first Fresnel peak.
Deformation Expression for Elements of Algebra
H. Omori; Y. Maeda; N. Miyazaki; A. Yoshioka
2011-04-09
The purpose of this paper is to give a notion of deformation of expressions for elements of algebra. Deformation quantization (cf.[BF]) deforms the commutative world to a non-commutative world. However, this involves deformation of expression of elements of algebras even from a commutative world to another commutative world. This is indeed a deformation of expressions for elements of algebra.
Cyclic performance of viscoelastic dielectric elastomers with solid hydrogel Yuanyuan Bai,1
Suo, Zhigang
of manufacturing or fabrication by 3D printing, silent operation, and capability of large deformation.1
Shells on a Sphere: Tectonic Plate Motion and Plate Boundary Deformation
Apel, Edwin Victor
2011-01-01
plate boundary deformation of Sakhalin from geodetic data,a pole located north of Sakhalin. The modeled AMU plateis sparse and diffuse. Sakhalin Island exhibits large
A Generalized Cohesive Zone Model of Peel Test for Pressure Sensitive Adhesives
Zhang, Liang
2010-01-16
itself. Generally, the failure of the adhesive is accompanied with a process of cavitation and fibrillation. Therefore, the cohesive zone is modeled as a continuous fibrillated region. A Maxwell model is employed to characterize the viscoelastic behavior...
Nonconforming finite element methods for the simulation of waves in viscoelastic solids
Sheen, Dongwoo
a , Juan E. Santos b , Dongwoo Sheen c,* a School of Civil, Urban, and Geosystem Engineering, Seoul of waves in two- and three-dimensional bounded viscoelastic media is described in the space frequency element methods are employed for the spatial discretization. Optimal error estimate in a broken energy
Wake measurements for flow around a sphere in a viscoelastic fluid Drazen Fabrisa)
Liepmann, Dorian
counterpart is made by a drag correction factor, K FD 6 0aUt , 3 where FD is the drag force on the sphere which balances the force due to gravity, ( s f)*( 4 3 ga3 ). The drag correc- tion factor is, in generalWake measurements for flow around a sphere in a viscoelastic fluid Drazen Fabrisa) Department
Exceptional negative thermal expansion and viscoelastic properties of graphene oxide paper
Zhong, Zhaohui
and viscoelastic properties in graphene oxide paper. The paper was prepared from aqueous GO dispersions using]. Graphene oxide (GO), likely the most important graphene derivative, has also been prepared by oxidizing and temperature. 2. Experimental 2.1. Preparation of GO and GO paper Graphene oxide was synthesized by oxidation of
of an LCP. Liquid crystal polymers are useful because the photo- induced LC to isotropic phase transitionPolymer communication Rapid viscoelastic switching of an ambient temperature range photo, temperature sweeps measured G' and G" from 80°C to -5°C and identified glass transition temperatures (Tg) at 2
J. Non-Newtonian Fluid Mech. 130 (2005) 96109 Forward roll coating flows of viscoelastic liquids
Natelson, Douglas
2005-01-01
J. Non-Newtonian Fluid Mech. 130 (2005) 96109 Forward roll coating flows of viscoelastic liquids G, USA Received 10 September 2004; received in revised form 23 July 2005 Abstract Roll coating to a substrate. Except at low speed, the two-dimensional film splitting flow that occurs in forward roll coating
Rothstein, Jonathan
the many existing web coating and printing techniques for large-scale fabrication such as slit, roll, dip]. The primary advantage of roll-to-roll processing that is large areas of coated/printed films can be processed March 2012 Keywords: Viscoelasticity Gravure printing Pickout process Extensional rheology Coating a b
PHYSICS OF FLUIDS 24, 051902 (2012) Self-propulsion in viscoelastic fluids: Pushers vs. pullers
Lauga, Eric
2012-01-01
PHYSICS OF FLUIDS 24, 051902 (2012) Self-propulsion in viscoelastic fluids: Pushers vs. pullers Lailai Zhu,1,a) Eric Lauga,2 and Luca Brandt1 1 Linn´e Flow Centre, KTH Mechanics, S-100 44 Stockholm, Sweden 2 Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500
Raghavan, Srinivasa
(andhence,theirlengthandflexibility)responds to changes in surfactant and salt concentration, nature of counterion, and temperature. Theory rheological master curves through time-temperature super- position.9-12 Temperature effects on wormlikeHighly Viscoelastic Wormlike Micellar Solutions Formed by Cationic Surfactants with Long
VISCOELASTIC BEHAVIOR OF POLYMER-THICKENED WATER-IN-OIL EMULSIONS
Natelson, Douglas
VISCOELASTIC BEHAVIOR OF POLYMER-THICKENED WATER-IN- OIL EMULSIONS MONTESI PEÑA HIRASAKI PASQUALI behavior of emulsions of water dispersed in a lubricant oil base and stabilized with a nonionic surfactant concentration, emulsions with and without polyisobutylene (PIB, MW = 2.1 ± 0.2 x 106 Da) added to the oil phase
Overall response of viscoelastic composites and polycrystals: exact asymptotic relations and
Paris-Sud XI, Université de
to a creep test (see Subsection 2.2 and Figure 1). For simplicity the present study will be focused emphasis on their transient response. First, two new asymptotic relations for the overall creep function: linear viscoelasticity, homogenization, effective creep function, particulate composites, polycrystals
3.22 Mechanical Properties of Materials Test 2: Viscoelasticity and Plasticity
Goldwasser, Shafi
are allowed to bring one 8.5" x 11" sheet into the test. 1. The creep behaviour of polyethylene is given3.22 Mechanical Properties of Materials Test 2: Viscoelasticity and Plasticity April 25, 2002 You by the creep compliance data in the table below. Creep compliance of Polyethylene t (hours) J(t) (psi-1) 0 0
Elastic and Viscoelastic Properties of Non-bulk Polymer Interphases in Nanotube-reinforced Polymers
Fisher, Frank
Elastic and Viscoelastic Properties of Non-bulk Polymer Interphases in Nanotube-reinforced Polymers polymer composite materials with outstanding mechanical, electrical, and thermal properties. A hurdle to nanoscale interactions between the embedded NTs and adjacent polymer chains. This interphase region
Habit tic deformity secondary to guitar playing
Wu, Jashin J
2009-01-01
KA. Treatment of habit- tic deformity with fluoxetine. ArchHabit tic deformity secondary to guitar playing Jashin J Wuchanges similar to the habit tic deformity may be produced
Gupta, Anupam
2015-01-01
The effects of viscoelasticity on the dynamics and break-up of fluid threads in microfluidic T-junctions are investigated using numerical simulations of dilute polymer solutions at changing the Capillary number ($\\mbox {Ca}$), i.e. at changing the balance between the viscous forces and the surface tension at the interface, up to $\\mbox{Ca} \\approx 3 \\times 10^{-2}$. A Navier-Stokes (NS) description of the solvent based on the lattice Boltzmann models (LBM) is here coupled to constitutive equations for finite extensible non-linear elastic dumbbells with the closure proposed by Peterlin (FENE-P model). We present the results of three-dimensional simulations in a range of $\\mbox{Ca}$ which is broad enough to characterize all the three characteristic mechanisms of breakup in the confined T-junction, i.e. ${\\it squeezing}$, ${\\it dripping}$ and ${\\it jetting}$ regimes. The various model parameters of the FENE-P constitutive equations, including the polymer relaxation time $\\tau_P$ and the finite extensibility para...
Variable focal length deformable mirror
Headley, Daniel (Albuquerque, NM); Ramsey, Marc (Albuquerque, NM); Schwarz, Jens (Albuquerque, NM)
2007-06-12
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.
Deformed Mittag-Leffler Polynomials
Stankovic, Miomir S; Rajkovic, Predrag M
2010-01-01
The starting point of this paper are the Mittag-Leffler polynomials introduced by H. Bateman [1]. Based on generalized integer powers of real numbers and deformed exponential function, we introduce deformed Mittag-Leffler polynomials defined by appropriate generating function. We investigate their recurrence relations, differential properties and orthogonality. Since they have all zeros on imaginary axes, we also consider real polynomials with real zeros associated to them.
Plasticity and deformation of crystals: Analogies to turbulence
Choi, Woosong; Papanikolaou, Stefanos; Sethna, James P
2011-01-01
We describe intriguing analogies between our model of material deformation (how crystals deform under load) and fluid turbulence (how liquids flow under shear). Our model present mathematical, physical, and computational challenges, but offer intriguing new predictions of fractal, scale-invariant structure formation for experiments. We show here that these challenges are shared with classic models of turbulence. In particular, we find precisely analogous physical and mathematical challenges associated with the formation of singularities in the evolving flows, and associated computational challenges with even defining a solution in the continuum limit where the grid size and the viscosities go to zero.
A model for predicting the evolution of damage in the plastic bonded explosive LX17
Seidel, Gary Don
2002-01-01
Viscoelastic cohesive zones are employed within the framework of a finite element code to model a two-phase particle-reinforced composite material consisting of a relatively stiff aggregate embedded in a copolymer binder. ...
Srivastava, Vikas
2010-01-01
Amorphous polymers are important engineering materials; however, their nonlinear, strongly temperature- and rate-dependent elastic-viscoplastic behavior is still not very well understood, and is modeled by existing ...
Chen, Yulong; Li, Ziwei; Wen, Shipeng; Zhang, Liqun; Yang, Qingyuan E-mail: LiuL@mail.buct.edu.cn; Zhong, Chongli; Liu, Li E-mail: LiuL@mail.buct.edu.cn
2014-09-14
The strain-amplitude dependence of viscoelastic behavior of model crosslinked elastomers containing various concentrations of spherical nanoparticles (NPs) was studied by non-equilibrium molecular dynamics simulation. All the filler NPs were in monodispersed state and the interactions between these particles were purely repulsive. The polymer–particle interactions were attractive and their interaction energies were tuned in a broad range. Through the computational study, many important features of the behavior of particle-reinforced elastomers observed in experiments, including the Payne effect, were successfully reproduced. It was shown that the magnitude of the Payne effect was found to depend on the polymer–particle interaction and the filler loading. By examining the microstructures of the simulation systems and their evolution during oscillatory shear, four different mechanisms for the role of the polymer–particle interactions in the Payne effect were revealed that consist of the debonding of polymer chains from NP surfaces, the breakage of polymer-shell-bridged NP network, the rearrangement of the NPs in the network into different layers and the shear-induced yielding of the rigid polymer shell in-between neighboring NPs.
The viscoelastic properties of linear-star blends
Lee, Jung Hun
2000-01-01
prediction for linear-star blend than the existing blend model. Due to the simplified scaling for constraint release, the generality of the linear-star blend model of present work is limited only for the high ML and low [Ø]S. Even though such restriction...
Quantum Field Theory Approach to the Optical Conductivity of Strained and Deformed Graphene
W. de Paula; a. Chaves; O. Oliveira; T. Frederico
2015-11-25
The computation of the optical conductivity of strained and deformed graphene is discussed within the framework of quantum field theory in curved spaces. The analytical solutions of the Dirac equation in an arbitrary static background geometry for one dimensional periodic deformations are computed, together with the corresponding Dirac propagator. Analytical expressions are given for the optical conductivity of strained and deformed graphene associated with both intra and interbrand transitions. The special case of small deformations is discussed and the result compared to the prediction of the tight-binding model.
Quantum Field Theory Approach to the Optical Conductivity of Strained and Deformed Graphene
de Paula, W; Oliveira, O; Frederico, T
2015-01-01
The computation of the optical conductivity of strained and deformed graphene is discussed within the framework of quantum field theory in curved spaces. The analytical solutions of the Dirac equation in an arbitrary static background geometry for one dimensional periodic deformations are computed, together with the corresponding Dirac propagator. Analytical expressions are given for the optical conductivity of strained and deformed graphene associated with both intra and interbrand transitions. The special case of small deformations is discussed and the result compared to the prediction of the tight-binding model.
Fluid-driven deformation of a soft granular material
Christopher W. MacMinn; Eric R. Dufresne; John S. Wettlaufer
2015-02-24
Compressing a porous, fluid-filled material will drive the interstitial fluid out of the pore space, as when squeezing water out of a kitchen sponge. Inversely, injecting fluid into a porous material can deform the solid structure, as when fracturing a shale for natural gas recovery. These poromechanical interactions play an important role in geological and biological systems across a wide range of scales, from the propagation of magma through the Earth's mantle to the transport of fluid through living cells and tissues. The theory of poroelasticity has been largely successful in modeling poromechanical behavior in relatively simple systems, but this continuum theory is fundamentally limited by our understanding of the pore-scale interactions between the fluid and the solid, and these problems are notoriously difficult to study in a laboratory setting. Here, we present a high-resolution measurement of injection-driven poromechanical deformation in a system with granular microsctructure: We inject fluid into a dense, confined monolayer of soft particles and use particle tracking to reveal the dynamics of the multi-scale deformation field. We find that a continuum model based on poroelasticity theory captures certain macroscopic features of the deformation, but the particle-scale deformation field exhibits dramatic departures from smooth, continuum behavior. We observe particle-scale rearrangement and hysteresis, as well as petal-like mesoscale structures that are connected to material failure through spiral shear banding.
Derivation of the action and symmetries of the q-deformed AdS_5 x S^5 superstring
Francois Delduc; Marc Magro; Benoit Vicedo
2014-09-01
We recently proposed an integrable q-deformation of the AdS_5 x S^5 superstring action. Here we give details on the hamiltonian origin and construction of this deformation. The procedure is a generalization of the one previously developed for deforming principal chiral and symmetric space sigma-models. We also show that the original psu(2,2|4) symmetry is replaced in the deformed theory by a classical analog of the quantum group U_q(psu(2,2|4)) with q real. The relation between q and the deformation parameter entering the action is given. The framework used to derive the deformation also enables to prove that at the hamiltonian level, the "maximal deformation" limit corresponds to an undeformed semi-symmetric space sigma-model with bosonic part dS_5 x H^5. Finally, we discuss the various freedoms in the construction.
Palmer, Jeffrey Shane
2008-01-01
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 ...
Mohammadyari, P; Faghihi, R; Shirazi, M Mosleh; Lotfi, M; Meigooni, A
2014-06-01
Purpose: the accuboost is the most modern method of breast brachytherapy that is a boost method in compressed tissue by a mammography unit. the dose distribution in uncompressed tissue, as compressed tissue is important that should be characterized. Methods: In this study, the mechanical behavior of breast in mammography loading, the displacement of breast tissue and the dose distribution in compressed and uncompressed tissue, are investigated. Dosimetry was performed by two dosimeter methods of Monte Carlo simulations using MCNP5 code and thermoluminescence dosimeters. For Monte Carlo simulations, the dose values in cubical lattice were calculated using tally F6. The displacement of the breast elements was simulated by Finite element model and calculated using ABAQUS software, from which the 3D dose distribution in uncompressed tissue was determined. The geometry of the model is constructed from MR images of 6 volunteers. Experimental dosimetery was performed by placing the thermoluminescence dosimeters into the polyvinyl alcohol breast equivalent phantom and on the proximal edge of compression plates to the chest. Results: The results indicate that using the cone applicators would deliver more than 95% of dose to the depth of 5 to 17mm, while round applicator will increase the skin dose. Nodal displacement, in presence of gravity and 60N forces, i.e. in mammography compression, was determined with 43% contraction in the loading direction and 37% expansion in orthogonal orientation. Finally, in comparison of the acquired from thermoluminescence dosimeters with MCNP5, they are consistent with each other in breast phantom and in chest's skin with average different percentage of 13.7±5.7 and 7.7±2.3, respectively. Conclusion: The major advantage of this kind of dosimetry is the ability of 3D dose calculation by FE Modeling. Finally, polyvinyl alcohol is a reliable material as a breast tissue equivalent dosimetric phantom that provides the ability of TLD dosimetry for validation.
Argatov, I; Mishuris, G; Ronken, S; Wirz, D
2012-01-01
In recent years, dynamic indentation tests have been shown to be useful both in identification of mechanical properties of biological tissues (such as articular cartilage) and assessing their viability. We consider frictionless flat-ended and spherical sinusoidally-driven indentation tests utilizing displacement-controlled loading protocol. Articular cartilage tissue is modeled as a viscoelastic material with a time-independent Poisson's ratio. We study the dynamic indentation stiffness with the aim of formulating criteria for evaluation the quality of articular cartilage in order to be able to discriminate its degenerative state. In particular, evaluating the dynamic indentation stiffness at the turning point of the flat-ended indentation test, we introduce the so-called incomplete storage modulus. Considering the time difference between the time moments when the dynamic stiffness vanishes (contact force reaches its maximum) and the dynamic stiffness becomes infinite (indenter displacement reaches its maximu...
Deformed Pseudospin Doublets as a Fingerprint of a Relativistic Supersymmetry in Nuclei
A. Leviatan
2010-08-09
The single-particle spectrum of deformed shell-model states in nuclei, is shown to exhibit a supersymmetric pattern. The latter involves deformed pseudospin doublets and intruder levels. The underlying supersymmetry is associated with the relativistic pseudospin symmetry of the nuclear mean-field Dirac Hamiltonian with scalar and vector potentials.
Low fault friction in Iran implies localized deformation for the ArabiaEurasia collision zone
Vernant, Philippe
Low fault friction in Iran implies localized deformation for the ArabiaEurasia collision zone P velocity field of the present-day deformation in Iran is modeled using a 3-dimensional (3D) finite element of the kinematics in Iran, but the complex velocity field of the surrounding South Caspian basin cannot be fitted
Modeling and Algorithmic Approaches to Constitutively-Complex, Micro-structured Fluids
Forest, Mark Gregory [University of North Carolina at Chapel Hill] [University of North Carolina at Chapel Hill
2014-05-06
The team for this Project made significant progress on modeling and algorithmic approaches to hydrodynamics of fluids with complex microstructure. Our advances are broken down into modeling and algorithmic approaches. In experiments a driven magnetic bead in a complex fluid accelerates out of the Stokes regime and settles into another apparent linear response regime. The modeling explains the take-off as a deformation of entanglements, and the longtime behavior is a nonlinear, far-from-equilibrium property. Furthermore, the model has predictive value, as we can tune microstructural properties relative to the magnetic force applied to the bead to exhibit all possible behaviors. Wave-theoretic probes of complex fluids have been extended in two significant directions, to small volumes and the nonlinear regime. Heterogeneous stress and strain features that lie beyond experimental capability were studied. It was shown that nonlinear penetration of boundary stress in confined viscoelastic fluids is not monotone, indicating the possibility of interlacing layers of linear and nonlinear behavior, and thus layers of variable viscosity. Models, algorithms, and codes were developed and simulations performed leading to phase diagrams of nanorod dispersion hydrodynamics in parallel shear cells and confined cavities representative of film and membrane processing conditions. Hydrodynamic codes for polymeric fluids are extended to include coupling between microscopic and macroscopic models, and to the strongly nonlinear regime.
Boundary-Aware Multi-Domain Subspace Deformation
Zhou, Kun
using node-wise corotational elasticity. With the proper construction of subspaces based the physics-based simulation of deformable objects. The basic idea is to project the high-dimensional equation of motion to a carefully chosen low-dimensional subspace to construct a re- duced model. Traditional global
Tri-axial Octupole Deformations and Shell Structure
W. D. Heiss; R. G. Nazmitdinov; R. A. Lynch
1999-04-28
Manifestations of pronounced shell effects are discovered when adding nonaxial octupole deformations to a harmonic oscillator model. The degeneracies of the quantum spectra are in a good agreement with the corresponding main periodic orbits and winding number ratios which are found by classical analysis.
DIFFUSION IN DEFORMING POROUS MEDIA R.E. SHOWALTER
of the deforming matrix and the pressure gradient of the diffusing pore fluid. In the classical consolidation process, a load is initially shared with the pore fluid, and with time the pore fluid pressure dissipates and application of mathematical models for the flow of fluids driven by the cou- pled pressure and stress
Degree-1 Earth deformation from very long baseline interferometry measurements
Faulds, James E.
of the center of mass of the Earth system through satellite orbit models and the former purely on observing earth and the center of mass of the entire Earth system (Earth, oceans and atmosphere). The load momentDegree-1 Earth deformation from very long baseline interferometry measurements D. Lavalle´e and G
A Painting Interface for Interactive Surface Deformations Jason Lawrence
A Painting Interface for Interactive Surface Deformations Jason Lawrence Princeton University. In this paper, we investigate combining these two approaches with a painting interface that gives the user direct, local control over a physical sim- ulation. The "paint" a user applies to the model defines its
Performance-Guided Character Bind Pose for Deformations
Pena, Benito
2011-08-08
Current production methods for creating a motion system for a deformable digital character model involve providing an underlying joint structure based o of a T-Pose, A-Pose or another arbitrary bind pose of the character. A bind pose is required...
A non-linear elastic constitutive framework for replicating plastic deformation in solids.
Roberts, Scott Alan; Schunk, Peter Randall
2014-02-01
Ductile metals and other materials typically deform plastically under large applied loads; a behavior most often modeled using plastic deformation constitutive models. However, it is possible to capture some of the key behaviors of plastic deformation using only the framework for nonlinear elastic mechanics. In this paper, we develop a phenomenological, hysteretic, nonlinear elastic constitutive model that captures many of the features expected of a plastic deformation model. This model is based on calculating a secant modulus directly from a material's stress-strain curve. Scalar stress and strain values are obtained in three dimensions by using the von Mises invariants. Hysteresis is incorporated by tracking an additional history variable and assuming an elastic unloading response. This model is demonstrated in both single- and multi-element simulations under varying strain conditions.
Quantum mechanical effects from deformation theory
Much, A. [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig, Germany and Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)] [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig, Germany and Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)
2014-02-15
We consider deformations of quantum mechanical operators by using the novel construction tool of warped convolutions. The deformation enables us to obtain several quantum mechanical effects where electromagnetic and gravitomagnetic fields play a role. Furthermore, a quantum plane can be defined by using the deformation techniques. This in turn gives an experimentally verifiable effect.
Nuclear reactions in hot stellar matter and nuclear surface deformation
V. Yu. Denisov
2006-11-13
Cross-sections for capture reactions of charged particles in hot stellar matter turn out be increased by the quadrupole surface oscillations, if the corresponding phonon energies are of the order of the star temperature. The increase is studied in a model that combines barrier distribution induced by surface oscillations and tunneling. The capture of charged particles by nuclei with well-deformed ground-state is enhanced in stellar matter. It is found that the influence of quadrupole surface deformation on the nuclear reactions in stars grows, when mass and proton numbers in colliding nuclei increase.
Vane shear determination of the visco-elastic shear modulus of submarine sediments
Stevenson, Herbert Scott
1973-01-01
viscoelastic theory and torque versus rotation data from vane shear tests. The modu- lus, G(t), is described by the power law: G(t) = G, t where t is time, and G, and n are constants. G, and n are deter- mined from vane tests on deep sediment core samples.... G, is rota- tion angle dependent. The validity of the procedure is supported by predict1ons of in situ vane test torque versus rotation curves wh1ch agree favorably with data obtained using an in s1tu vane device. G, correlates with maximum vane...
Accounting for inertia effects to access the high-frequency microrheology of viscoelastic fluids
P. Domínguez-García; Frédéric Cardinaux; Elena Bertseva; László Forró; Frank Scheffold; Sylvia Jeney
2014-12-03
We study the Brownian motion of microbeads immersed in water and in a viscoelastic wormlike micelles solution by optical trapping interferometry and diffusing wave spectroscopy. Through the mean-square displacement obtained from both techniques, we deduce the mechanical properties of the fluids at high frequencies by explicitly accounting for inertia effects of the particle and the surrounding fluid at short time scales. For wormlike micelle solutions, we recover the 3/4 scaling exponent for the loss modulus over two decades in frequency as predicted by the theory for semiflexible polymers.
Viscoelastic modes in a strongly coupled, cold, magnetized dusty plasma
Banerjee, Debabrata; Mylavarapu, Janaki Sita; Chakrabarti, Nikhil
2010-11-15
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.
Viscoelastic modes in a strongly coupled cold magnetized dusty plasma
Banerjee, Debabrata; Chakrabarti, Nikhil
2013-01-01
A generalized hydrodynamical model has been used to study low frequency modes in a strongly coupled, cold, magnetized dusty plasma. Such plasmas exhibit elastic properties due to 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.
Z. Haghshenasfard; M. H. Naderi; M. Soltanolkotabi
2008-01-16
In this paper, we investigate the propagation of a weak optical probe pulse in an f-deformed Bose- Einstein condensate (BEC) of a gas with the -type three- level atoms in the electromagnetically induced transparency (EIT) regime. We use an f- deformed generalization of an effective two- level quantum model of the three- level configuration in which the Gardiner phonon operators for BEC are deformed by an operator- valued function, f(n), of the particle- number operator n. With making use of the quantum approach of the angular momentum theory we obtain the eigenvalues and eigenfunctions of the system up to first order approximation. We consider the collisions between the atoms as a special kind of f- deformation. The collision rate k is regarded as the deformation parameter and light propagation in the deformed BEC is analyzed. In particular, we show that the absorptive and dispersive properties of the deformed condensate can be controlled effectively by changing the deformation parameter k and the total number of atoms. We find that by increasing the value of k the group velocity of the probe pulse changes, through deformed condensate, from subluminal to superluminal.
Spin paramagnetic deformation of a neutron star
Suvorov, A G; Melatos, A
2015-01-01
Quantum mechanical corrections to the hydromagnetic force balance equation, derived from the microscopic Schr\\"{o}dinger-Pauli theory of quantum plasmas, modify the equilibrium structure and hence the mass quadrupole moment of a neutron star. It is shown here that the dominant effect --- spin paramagnetism --- is most significant in a magnetar, where one typically has $\\mu_{B}|\\boldsymbol{B}|\\gtrsim k_B T_e$, where $\\mu_{B}$ is the Bohr magneton, $\\boldsymbol{B}$ is the magnetic field, and $T_e$ is the electron temperature. The spin paramagnetic deformation of a nonbarotropic magnetar with a linked poloidal-toroidal magnetic field is calculated to be up to ${{\\sim 10}}$ times greater than the deformation caused solely by the Lorentz force. It depends on the degree of Pauli blocking by conduction electrons and the propensity to form magnetic domains, processes which are incompletely modelled at magnetar field strengths. The star becomes more oblate, as the toroidal field component strengthens. The result impli...
Noncommutative supergeometry, duality and deformations
Albert Schwarz
2002-10-28
We introduce a notion of $Q$-algebra that can be considered as a generalization of the notion of $Q$-manifold (a supermanifold equipped with an odd vector field obeying $\\{Q,Q\\} =0$). We develop the theory of connections on modules over $Q$-algebras and prove a general duality theorem for gauge theories on such modules. This theorem containing as a simplest case $SO(d,d,{\\bf Z})$-duality of gauge theories on noncommutative tori can be applied also in more complicated situations. We show that $Q$-algebras appear naturally in Fedosov construction of formal deformation of commutative algebras of functions and that similar $Q$-algebras can be constructed also in the case when the deformation parameter is not formal.
Z. Haghshenasfard; M. H. Naderi; M. Soltanolkotabi
2008-07-11
In this paper, we investigate the spectrum of light scattered from a Bose-Einstein condensate in the framework of f-deformed boson. We use an f-deformed quantum model in which the Gardiners phonon operators for BEC are deformed by an operator-valued function, f(n), of the particle-number operator n. We consider the collisions between the atoms as a special kind of f-deformation. The collision rate k is regarded as the deformation parameter and the spectrum of light scattered from the deformed BEC is analyzed. In particular, we find that with increasing the values of deformation parameters k and eta=1/N (N, total number of condensate atoms) the scattering spectrum shows deviation from the spectrum associated with nondeformed Bose-Einstein condensate.
Modeling the growth and dissolution of clots in flowing blood
Mohan, Anand
2006-10-30
. . . . . . . . . . . . . 45 D. Model corroboration . . . . . . . . . . . . . . . . . . . . . 51 1. Clot formation and growth in quiescent plasma . . . . 51 2. Clot dissolution in quiescent plasma . . . . . . . . . . 54 E. Clinical correlations of model predictions... . . . . . . . . . . . . . . . . . 63 C. A viscoelastic liquid model for a coarse ligated plasma clot 63 1. Constitutive assumptions . . . . . . . . . . . . . . . . 63 D. Model corroboration . . . . . . . . . . . . . . . . . . . . . 65 1. Application to oscillatory flow...
The effects of lithology and initial fault angle in physical models of fault-propagation folds
McLain, Christopher Thomas
2001-01-01
with a weak brittle layer that deforms by faulting and fracturing (dried pottery clay simulates an interbedded siliciclastic unit). The models were deformed in a triaxial deformation rig at confining pressure of 50 Mpa at room temperature. Each model...
Physical and Statistical Models in Deformation Geodesy
Lipovsky, Brad
2011-01-01
2008), Mississippi Delta subsidence primarily caused bySultan (2009), Land subsidence in the nile delta: inferences2006), Space geodesy: Subsidence and ?ooding in New Orleans,
A TWO-DIMENSIONAL FEM CODE FOR THE ANALYSIS OF LARGE DEFORMATIONS OF
Zabaras, Nicholas J.
A TWO-DIMENSIONAL FEM CODE FOR THE ANALYSIS OF LARGE DEFORMATIONS OF HYPERELASTIC VISCOPLASTIC, a hyper elastic formulation was considered by Weber and Anand 3]. In this work, the elasticity is modelled
Physical Simulation of an Embedded Surface Mesh Involving Deformation and Fracture
Clack, Billy
2012-07-16
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...
Peltier, W. Richard
of the Earth W. R. Peltier,1 I. Shennan,2 R. Drummond1 and B. Horton2 1 Department of Physics, University viscoelastic theory of the glacial isostatic adjustment (GIA) process, most recently reviewed in Peltier (1998a on the inverse problem for mantle viscosity (see the papers by Peltier 1998b and Wieczerkowski et al. 1999
A simplified model for red cell dynamics in small blood vessels
Piero Olla
1998-11-20
A simple mechanism for the confinement of red cells in the middle of narrow blood vessels is proposed. In the presence of a quadratic shear, red cells deform in such a way to loose fore-aft symmetry and to achieve a fixed orientation with respect to the flow. This leads to a drift away from the vessel walls, when the vessel diameter goes below a critical value depending on the viscoelastic properties and the dimensions of the cell.
Tree Level Metastability and Gauge Mediation in Baryon Deformed SQCD
Barnard, James
2009-01-01
We investigate supersymmetric QCD with gauge group SU(2) and a baryon deformation to the superpotential. The existence of an uplifted vacuum at the origin with tree level metastability is demonstrated. When this model is implemented in a direct gauge mediation scenario we therefore find gaugino masses which are comparable to sfermion masses and parameterised by an effective number of messengers 1/8. All deformations are well motivated by appealing to the electric theory and an R-symmetry. This R-symmetry is explicitly broken by the same term responsible for supersymmetry breaking. Moreover, the model does not suffer from the Landau pole problem and we find that it can be described in terms of just two scales: the weak scale and a high scale like the Planck or GUT scale. The model can be tested by searching for new particles at the TeV scale charged under the visible sector gauge group.
Tree Level Metastability and Gauge Mediation in Baryon Deformed SQCD
James Barnard
2010-02-15
We investigate supersymmetric QCD with gauge group SU(2) and a baryon deformation to the superpotential. The existence of an uplifted vacuum at the origin with tree level metastability is demonstrated. When this model is implemented in a direct gauge mediation scenario we therefore find gaugino masses which are comparable to sfermion masses and parameterised by an effective number of messengers 1/8. All deformations are well motivated by appealing to the electric theory and an R-symmetry. This R-symmetry is explicitly broken by the same term responsible for supersymmetry breaking. Moreover, the model does not suffer from the Landau pole problem and we find that it can be described in terms of just two scales: the weak scale and a high scale like the Planck or GUT scale. The model can be tested by searching for new particles at the TeV scale charged under the visible sector gauge group.
Formation Flying and Deformable Instruments
Rio, Yvon
2009-05-11
Astronomers have always attempted to build very stable instruments. They fight all that can cause mechanical deformation or image motion. This has led to well established technologies (autoguide, active optics, thermal control, tip/tilt correction), as well as observing methods based on the use of controlled motion (scanning, micro scanning, shift and add, chopping and nodding). Formation flying disturbs this practice. It is neither possible to reduce the relative motion to very small amplitudes, nor to control it at will. Some impacts on Simbol-X instrument design, and operation are presented.
Deformed Geometric Algebra and Supersymmetric Quantum Mechanics
Peter Henselder
2006-09-09
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.
Higher Order Deformations of Complex Structures
Eric D'Hoker; Duong H. Phong
2015-06-23
Deformations of complex structures by finite Beltrami differentials are considered on general Riemann surfaces. Exact formulas to any fixed order are derived for the corresponding deformations of the period matrix, Green's functions, and correlation functions in conformal field theories with vanishing total central charge. The stress tensor is shown to give a simple representation of these deformations valid to all orders. Such deformation formulas naturally enter into the evaluation of superstring amplitudes at two-loop order with Ramond punctures, and at higher loop order, in the supergravity formulation of the RNS superstring.
Higher Order Deformations of Complex Structures
D'Hoker, Eric
2015-01-01
Deformations of complex structures by finite Beltrami differentials are considered on general Riemann surfaces. Exact formulas to any fixed order are derived for the corresponding deformations of the period matrix, Green's functions, and correlation functions in conformal field theories with vanishing total central charge. The stress tensor is shown to give a simple representation of these deformations valid to all orders. Such deformation formulas naturally enter into the evaluation of superstring amplitudes at two-loop order with Ramond punctures, and at higher loop order, in the supergravity formulation of the RNS superstring.
Improving Preclinical Testing of Deformity Correction Surgery
Borkowski, Sean Leo
2015-01-01
permit subsequent testing. ” In other words, non-destructivenon-destructive and do not cause plastic deformation of the intervening tissues or spine structure, thus allowing repeated testing,
Kelemen, Peter
2012-08-24
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.
Jones, Ryan Edward, 1974-
2004-01-01
Understanding how fluids respond to various deformations is of great importance to a spectrum of disciplines ranging from bio-medical research on joint replacements to sealing technology in industrial machinery. Specifically, ...
Influence of shockwave obliquity on deformation twin formation in Ta
Gray, George T., III; Livescu, V; Cerreta, E K; Mason, T A; Maudlin, P J; Bingert, J F
2009-02-18
Energetic loading subjects a material to a 'Taylor wave' (triangular wave) loading profile that experiences an evolving balance of hydrostatic (spherical) and deviatoric stresses. While much has been learned over the past five decades concerning the propensity of deformation twinning in samples shockloaded using 'square-topped' profiles as a function of peak stress, achieved most commonly via flyer plate loading, less is known concerning twinning propensity during non-I-dimensional sweeping detonation wave loading. Systematic small-scale energetically-driven shock loading experiments were conducted on Ta samples shock loaded with PEFN that was edge detonated. Deformation twinning was quantified in post-mortem samples as a function of detonation geometry and radial position. In the edge detonated loading geometry examined in this paper, the average volume fraction of deformation twins was observed to drastically increase with increasing shock obliquity. The results of this study are discussed in light of the formation mechanisms of deformation twins, previous literature studies of twinning in shocked materials, and modeling of the effects of shock obliquity on the evolution of the stress tensor during shock loading.
FEM Analysis ofFEM Analysis of Deformation and Fracture ofDeformation and Fracture of
Grujicic, Mica
FEM Analysis ofFEM Analysis of Deformation and Fracture ofDeformation and Fracture of Deformation and Fracture in Polycrystalline -TiAl + 2-Ti3Al Single Crystals #12;Use of -TiAl + 2-Ti3Al Alloys-Temperature Ductility ·Low Ambient-Temperature Fracture Toughness (KIC
Jordan Hristov
2011-07-26
Integral balance solution employing entire domain approximation and the penetration dept concept to the Stokes' first problem of a viscoelastic generalized second grade fluid has been developed. The solution has been performed by a parabolic profile with an unspecified exponent allowing optimization through minimization of the norm over the domain of the penetration depth. The closed form solution explicitly defines two dimensionless similarity variables and, responsible for the viscous and the elastic responses of the fluid to the step jump at the boundary. The solution was developed with three forms of the governing equation through its two dimensional forms (the main solution and example 1) and the dimensionless version showing various sides of the flow field and how the dimensionless groups control it: mainly the effect of the Deborah number. Numerical simulations demonstrating the effect of the various operating parameter and fluid properties on the developed flow filed have been performed.
Houston, Jack E.; Grest, Gary Stephen; Moore, Nathan W.; Feibelman, Peter J.
2010-09-01
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.
Xuan, Xiangchun "Schwann"
Biomicrofluidics 7, 024106 (2013); 10.1063/1.4795856 Lubricated extensional flow of viscoelastic fluids control of the flow rate and a large consumption of the sheath fluid are the drawbacks of this method
Large Mesh Deformation Using the Volumetric Graph Laplacian
Kazhdan, Michael
Large Mesh Deformation Using the Volumetric Graph Laplacian Kun Zhou1 Jin Huang2 John Snyder3 Related Work Deformation on Volumetric Graphs Deformation from 2D curves Results Conclusions #12;11/21/2007 Bhaskar Kishore 3 Outline Introduction Related Work Deformation on Volumetric Graphs Deformation from
Ligand mediated adhesive mechanics of two deformed spheres
Sircar, Sarthok; Nguyen, Giang; Roberts, Anthony J
2015-01-01
A self-consistent model is developed to investigate attachment / detachment kinetics of two soft, deformable microspheres with irregular surface and coated with flexible binding ligands. The model highlights how the microscale binding kinetics of these ligands as well as the attractive/repulsive potential of the charged surface affects the static deformed configuration of the spheres. It is shown that in the limit of smooth, neutral charged surface (i.e., the Debye length, $\\kappa \\rightarrow \\infty $), interacting via elastic binders (i.e., the stiffness coefficient, $\\lambda \\rightarrow 0$) the adhesion mechanics approaches the regime of application of the JKR theory, and in this particular limit, the contact radius scales with the particle radius, according to the scaling law, $R_c\\propto R^{\\frac{2}{3}}$. We show that adhesion dominates in larger particles with highly charged surface and with resilient binders. Normal stress distribution within the contact area fluctuates with the binder stiffness coeffic...
Nuclear dynamical deformation induced hetero- and euchromatin positioning
Akinori Awazu
2015-06-12
The contributions of active deformation dynamics in cell nuclei to the intra-nuclear positioning of hetero- and euchromatin are investigated. We analyzed the behaviors of model chains containing two types of regions, one with high and the other with low mobility, confined in a pulsating container. Here, the regions with high and low mobility represent eu- and heterochromatic regions, respectively, and the pulsating container simulates a nucleus exhibiting dynamic deformations. The Brownian dynamics simulations of this model show that the positioning of low mobility regions transition from sites near the periphery to the central region of the container if the affinity between low mobility regions and the container periphery disappears. Here, the former and latter positioning are similar to the "conventional" and "inverted" chromatin positioning observed in nuclei of normal differentiated cells and cells lacking Lamin-related proteins like mouse rod photoreceptor cell.
Intrinsic excitations in deformed nuclei: characteristic predictions of the IBA
Casten, R.F.
1982-01-01
Deformed nuclei represent perhaps the largest and best studied class of nuclear level schemes. The Interacting Boson Approximation (IBA) model is devised so as to provide a general framework for the description of low lying collective states in nuclei spanning vibrational, rotational (i.e., deformed) and axially asymmetric types as well as the transitional species intermediate between these limiting cases. The juxtaposition of these two statements makes it all the more surprising that until recently there had been no thorough test of the model in such nuclei. Partly, the explanation for this lies in the type of data required for an adequate test. Since the IBA predicts a broad range of collective states it requires a correspondingly thorough empirical test. Moreover, in deformed nuclei, though the characteristic predictions that distinguish the IBA from the traditional, familiar collective model of harmonic ..beta.. and ..gamma.. vibrations are important, their clearest manifestation occurs in very weak, hard-to-detect low energy transitions between excited vibrational bands (in particular between ..beta.. and ..gamma.. bands), that had not heretofore been systematically observed. The present brief summary will begin with a review of the properties of the (n,..gamma..) reaction that render it a useful empirical tool for such studies, and follow this with a description of the results of the /sup 168/Er study and the application of the IBA model to the resultant level scheme. The discussion will then be generalized to other deformed nuclei and to the inherent systematic predictions that must characterize the IBA for such nuclei. Many of these ideas will be related to the role of finite boson number in the IBA.
A Painting Interface for Interactive Surface Deformations
A Painting Interface for Interactive Surface Deformations Jason Lawrence a Thomas Funkhouser a a with a painting interface that gives the user direct, local control over a physical simulation. The "paint" a user- locity, the user can effect surface deformations. We have found that this painting metaphor gives
To mechanics of deformation, flow, and fracture
S. L. Arsenjev
2008-09-23
It is stated in the main in essence new approach to mechanics of the stressed state of the solid body from statistically isotropic material and the homogeneous liquid dynamics. The approach essence is in the detected property of the core-shell spontaneous structurization of internal energy of the solid and liquid bodies in its natural state and under action of external forces. The method elements of construction of physically adequate model of the stressed state of the solid and liquid bodies, reproduced exactly its behavior on the stages of elastic and plastic deformation, flow and fracture, are stated. It is adduced a number of the examples of the stressed state construction of the simple form bodies under action of its tension, compression, torsion and at its contact interaction. For the first time it is adduced structure of the principal - normal - stresses in cylindrical bar under action of the torsion moment. The detected property and the developed method is one of necessary bases for construction of physically adequate mathematical model of the stressed state of the body and fluid in contrast to traditional approach.
Nikoleris, Teo
1988-01-01
NUMERICAL SIMULATION OF THE NON-ISOTHERMAL DEVELOPING FLOXV OF A NONLINEAR VISCOELASTIC FLUID IN A RECTANGULAR CHANNEL A Thesis by TEO NIKOLERIS Submitted to the Graduate College of Texas A&M University in partial fulfillment... developing flow of a nonlinear viscoelas- tic fluid. The temperature dependence of the rheological parameters was imposed using an Arrhenius-like exponential relationship. The flow was creeping, at the early stages of thermal development and wall cooling...
Roberts-Tompkins, Altramese L.
2010-07-14
fulfillment of the requirements for the degree of MASTER OF SCIENCE December 2009 Major Subject: Mechanical Engineering VISCOELASTIC ANALYSIS OF SANDWICH BEAMS HAVING ALUMINUM AND FIBER-REINFORCED POLYMER SKINS WITH A POLYSTYRENE FOAM... CORE A Thesis by ALTRAMESE LASH? ROBERTS-TOMPKINS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee...
First Generation Advanced High-Strength Steels Deformation Fundamental...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Generation Advanced High-Strength Steels Deformation Fundamentals First Generation Advanced High-Strength Steels Deformation Fundamentals 2012 DOE Hydrogen and Fuel Cells Program...
Deformation mechanisms in a ferritic superalloy revealed by in...
Office of Scientific and Technical Information (OSTI)
Deformation mechanisms in a ferritic superalloy revealed by in situ neutron diffraction studies at elevated temperatures Citation Details In-Document Search Title: Deformation...
Three-dimensional gravity and deformations of relativistic symmetries
Trzesniewski, T
2015-01-01
It is possible that relativistic symmetries become deformed in the semiclassical regime of quantum gravity. Mathematically, such deformations lead to the noncommutativity of spacetime geometry and non-vanishing curvature of momentum space. The best studied example is given by the $\\kappa$-Poincar\\'e Hopf algebra, associated with $\\kappa$-Minkowski space. On the other hand, the curved momentum space is a well-known feature of particles coupled to three-dimensional gravity. The purpose of this thesis was to explore some properties and mutual relations of the above two models. In particular, I study extensively the spectral dimension of $\\kappa$-Minkowski space. I also present an alternative limit of the Chern-Simons theory describing three-dimensional gravity with particles. Then I discuss the spaces of momenta corresponding to conical defects in higher dimensional spacetimes. Finally, I consider the Fock space construction for the quantum theory of particles in three-dimensional gravity.
Deformable elastic network refinement for low-resolution macromolecular crystallography
Schröder, Gunnar F.; Levitt, Michael; Brunger, Axel T.
2014-09-01
An overview of applications of the deformable elastic network (DEN) refinement method is presented together with recommendations for its optimal usage. Crystals of membrane proteins and protein complexes often diffract to low resolution owing to their intrinsic molecular flexibility, heterogeneity or the mosaic spread of micro-domains. At low resolution, the building and refinement of atomic models is a more challenging task. The deformable elastic network (DEN) refinement method developed previously has been instrumental in the determinion of several structures at low resolution. Here, DEN refinement is reviewed, recommendations for its optimal usage are provided and its limitations are discussed. Representative examples of the application of DEN refinement to challenging cases of refinement at low resolution are presented. These cases include soluble as well as membrane proteins determined at limiting resolutions ranging from 3 to 7 Å. Potential extensions of the DEN refinement technique and future perspectives for the interpretation of low-resolution crystal structures are also discussed.
Surface deformation and shear flow in ligand mediated cell adhesion
Sircar, Sarthok
2015-01-01
We present a single, unified, multi-scale model to study the attachment\\detachment dynamics of two deforming, near spherical cells, coated with binding ligands and subject to a slow, homogeneous shear flow in a viscous fluid medium. The binding ligands on the surface of the cells experience attractive and repulsive forces in an ionic medium and exhibit finite resistance to rotation via bond tilting. The macroscale drag forces and couples describing the fluid flow inside the small separation gap between the cells, are calculated using a combination of methods in lubrication theory and previously published numerical results. For a select range of material and fluid parameters, a hysteretic transition of the sticking probability curves between the adhesion and fragmentation domain is attributed to a nonlinear relation between the total microscale binding forces and the separation gap between the cells. We show that adhesion is favored in highly ionic fluids, increased deformability of the cells, elastic binders ...
Optical Deformations in Solar Glass Filters for High Precision Astrometry
Sigismondi, Costantino; Boscardin, Sérgio Calderari; Penna, Jucira Lousada; Reis-Neto, Eugênio
2015-01-01
Measuring the solar diameter at all position angles gives the complete figure of the Sun. Their asphericities have implications in classical physics and general relativity, and the behavior of the optical systems used in the direct measurements is to be known accurately. A solar filter is a plane-parallel glass with given absorption, and here we study the departures from the parallelism of the faces of a crystal slab 5 mm thick, because of static deformations. These deformations are rescaled to the filter's dimensions. Related to the Solar Disk Sextant experiment and to the Reflecting Heliometer of Rio de Janeiro a simplified model of the influences of the inclination between the external and the internal surfaces of a glass solar filter, is discussed.
Deformation of Silica Aerogel During Fluid Adsorption
Tobias Herman; James Day; John Beamish
2005-06-30
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.
Supersymmetric Deformations of Maximally Supersymmetric Gauge Theories
M. Movshev; A. Schwarz
2012-06-19
We study supersymmetric and super Poincar\\'e invariant deformations of ten-dimensional super Yang-Mills theory and of its dimensional reductions. We describe all infinitesimal super Poincar\\'e invariant deformations of equations of motion of ten-dimensional super Yang-Mills theory and its reduction to a point; we discuss the extension of them to formal deformations. Our methods are based on homological algebra, in particular, on the theory of L-infinity and A-infinity algebras. The exposition of this theory as well as of some basic facts about Lie algebra homology and Hochschild homology is given in appendices.
A non-local, ordinary-state-based viscoelasticity model for peridynamics.
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563 LLNL(Technicalentanglements for linearA new(Conference) |
A non-local, ordinary-state-based viscoelasticity model for peridynamics.
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563 LLNL(Technicalentanglements for linearA new(Conference)
Lee, M H [Ames Laboratory; Park, E S [Samsung Electronics Co., LTD; Ott, R T [Ames Laboratory; Kim, B S [Korea Institute of Industrial Technology; Eckert, J [Institute for Complex Materials
2014-08-11
We evaluated the role of effective strain on the plasticity of metallic glasses related to springback phenomena in both ductile Zr-based metallic glass and brittle Hf-based metallic glass. Experimental investigations of the deformation behavior and the intrinsic mechanical properties of metallic glass were performed by room temperature L-bending deformation. The modeling analysis clearly shows that an inhomogeneous effective strain for initiating shear band is generated during deformation, with the brittleness of a metallic glass being dependent on the effective strain reaching the critical fracture strain of the glass. The combined experimental and modeling results reveal broad and general criteria that should allow for deformability of a wide-variety of glass-forming alloys by adjusting the effective strain during deformation.
A Quantum Affine Algebra for the Deformed Hubbard Chain
Niklas Beisert; Wellington Galleas; Takuya Matsumoto
2012-08-12
The integrable structure of the one-dimensional Hubbard model is based on Shastry's R-matrix and the Yangian of a centrally extended sl(2|2) superalgebra. Alcaraz and Bariev have shown that the model admits an integrable deformation whose R-matrix has recently been found. This R-matrix is of trigonometric type and here we derive its underlying exceptional quantum affine algebra. We also show how the algebra reduces to the above mentioned Yangian and to the conventional quantum affine sl(2|2) algebra in two special limits.
A Quantum Affine Algebra for the Deformed Hubbard Chain
Beisert, Niklas; Matsumoto, Takuya
2011-01-01
The integrable structure of the one-dimensional Hubbard model is based on Shastry's R-matrix and the Yangian of a centrally extended sl(2|2) superalgebra. Alcaraz and Bariev have shown that the model admits an integrable deformation whose R-matrix has recently been found. This R-matrix is of trigonometric type and here we derive its underlying exceptional quantum affine algebra. We also show how the algebra reduces to the above mentioned Yangian and to the conventional quantum affine sl(2|2) algebra in two special limits.
MEMS deformable mirror CubeSat testbed
Marinan, Anne D.
To meet the high contrast requirement of 1 × 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 are ...
A fluid pressure and deformation analysis for geological sequestration of carbon dioxide
Xu, Zhijie; Fang, Yilin; Scheibe, Timothy D.; Bonneville, Alain
2012-06-07
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.
Nuclear ground-state masses and deformations: FRDM(2012)
Moller, P; Ichikawa, T; Sagawa, H
2015-01-01
We tabulate the atomic mass excesses and binding energies, ground-state shell-plus-pairing corrections, ground-state microscopic corrections, and nuclear ground-state deformations of 9318 nuclei ranging from $^{16}$O to $A=339$. The calculations are based on the finite-range droplet macroscopic model and the folded-Yukawa single-particle microscopic model. Relative to our FRDM(1992) mass table in {\\sc Atomic Data and Nuclear Data Tables} [{\\bf 59} 185 (1995)], the results are obtained in the same model, but with considerably improved treatment of deformation and fewer of the approximations that were necessary earlier, due to limitations in computer power. The more accurate execution of the model and the more extensive and more accurate experimental mass data base now available allows us to determine one additional macroscopic-model parameter, the density-symmetry coefficient $L$, which was not varied in the previous calculation, but set to zero. Because we now realize that the FRDM is inaccurate for some high...
Simulation of Coating -Visco-Elastic liquid in the Mico-Nip of Metering Size Press
El-Sadi, Haifa
2008-01-01
For a set of operating conditions and coating color formulations, undesirable phenomena like color spitting and coating ribs may be triggered in the Micro-nip during the coating process. Therefore, our interest in this work focus on another parameter affect on the undesirable phenomena as the vortices in the Micro-nip. The problem deals with the flow through the Micro-nip of metering size press. The flow enters and exits at a tangential velocity of 20 m/s between two rollers with diameter 80 cm and 60 -m apart. In the upper and bottom part of the domain the angular velocity is 314 rad /s. It has one sub-domain. Previous studies focus on the Micro-nip without considering the inertia and the viscoelasticity of the material. Roll coating is a technique commonly used in the coating industry to meter a thin fluid film on a moving substrate. During the film formation, the fluid is subjected to very high shear and extensional rates over a very short period of time. The fluid domain changes as a function of the hydro...
Toshimasa Takanohashi; Takahiro Shishido; Ikuo Saito; Kensuke Masaki; Atsushi Dobashi; Kiyoshi Fukada [National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan)
2006-12-15
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.
Influence of plastic deformation on bimaterial fault rupture directivity
Dmowska, Renata
Influence of plastic deformation on bimaterial fault rupture directivity Nora DeDontney,1 Elizabeth of the role of the stress state on the distribution of plastic deformation and the direction of preferred in determining the location of plastic deformation. For different orientations, plastic deformation can
Large Deformation of Nitinol Under Shear Dominant Loading
Daly, Samantha
Large Deformation of Nitinol Under Shear Dominant Loading S. Daly & D. Rittel & K. Bhattacharya & G in Nitinol under large shear- dominated deformation are presented. To achieve a shear- dominated deformation transformation that is seen in uniaxial testing. The shear-dominant deformation of Nitinol in the plastic regime
Lindquist, A. K.; Feinberg, J. M.; Harrison, R. J.; Loudon, J. C.; Newell, A. J.
2015-03-19
In this study, we deformed samples cut from a single magnetite octahedron and used transmission electron microscopy (TEM) and magnetic measurements to experimentally verify earlier computational models of magnetic domain wall pinning by dislocations...
Automated Brain Shift Correction Using A Pre-computed Deformation Atlas
Frey, Pascal
Automated Brain Shift Correction Using A Pre-computed Deformation Atlas Prashanth Dumpuria Dr. Reid, USA ABSTRACT Compensating for intraoperative brain shift using computational models has shown preoperatively and are combined with the help of a statistical model to predict the intraoperative brain shift
Temperature effects on deformation and serration behavior of high-entropy alloys (HEAs)
Antonaglia, J.; Xie, X.; Tang, Z.; Tsai, C. -W.; Qiao, J. W.; Zhang, Y.; Laktionova, M. O.; Tabachnikova, E. D.; Yeh, J. W.; Senkov, O. N.; Gao, M. C.; Uhl, J. T.; Liaw, P. K.; Dahmen, K. A.
2014-09-16
Many materials are known to deform under shear in an intermittent way with slip avalanches detected as acoustic emission and serrations in the stress–strain curves. Similar serrations have recently been observed in a new class of materials, called high-entropy alloys (HEAs). Here, we discuss the serration behaviors of several HEAs from cryogenic to elevated temperatures. The experimental results of slow compression and tension tests are compared with the predictions of a slip-avalanche model for the deformation of a broad range of solids. The results shed light on the deformation processes in HEAs. Temperature effects on the distributions of stress drops and the decrease of the cutoff (i.e., of the largest observed slip size) for increasing temperature qualitatively agree with the model predictions. As a result, the model is used to quantify the serration characteristics of HEAs, and pertinent implications are discussed.
Temperature effects on deformation and serration behavior of high-entropy alloys (HEAs)
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Antonaglia, J.; Xie, X.; Tang, Z.; Tsai, C. -W.; Qiao, J. W.; Zhang, Y.; Laktionova, M. O.; Tabachnikova, E. D.; Yeh, J. W.; Senkov, O. N.; et al
2014-09-16
Many materials are known to deform under shear in an intermittent way with slip avalanches detected as acoustic emission and serrations in the stress–strain curves. Similar serrations have recently been observed in a new class of materials, called high-entropy alloys (HEAs). Here, we discuss the serration behaviors of several HEAs from cryogenic to elevated temperatures. The experimental results of slow compression and tension tests are compared with the predictions of a slip-avalanche model for the deformation of a broad range of solids. The results shed light on the deformation processes in HEAs. Temperature effects on the distributions of stress dropsmore »and the decrease of the cutoff (i.e., of the largest observed slip size) for increasing temperature qualitatively agree with the model predictions. As a result, the model is used to quantify the serration characteristics of HEAs, and pertinent implications are discussed.« less
Deforming convex RP3-structures on 3-orbifolds Deforming convex RP3-structures on 3-orbifolds
Choi, Suhyoung
Deforming convex RP3-structures on 3-orbifolds Deforming convex RP3-structures on 3-orbifolds-structures on 3-orbifolds Introduction Orbifolds and RPn-structures Orbifolds By an n-dimensional orbifold . an inclusion Uj Ui induces an equivariant map ~Uj ~Ui with respect to Gj Gi . A RPn-structure on an orbifold
Deformation quantization of the Pais-Uhlenbeck fourth order oscillator
Jasel Berra-Montiel; Alberto Molgado; Efraín Rojas
2015-05-12
We analyze the quantization of the Pais-Uhlenbeck fourth order oscillator within the framework of deformation quantization. Our approach exploit the Noether symmetries of the system by proposing integrals of motion as the variables to obtain a solution to the -genvalue equation, namely the Wigner function. We also obtain, by means of a quantum canonical transformation the wave function associated to the Schr\\"odinger equation of the system. We show that unitary evolution of the system is guaranteed by means of the quantum canonical transformation and via the properties of the constructed Wigner function, even in the so called equal frequency limit of the model, in agreement with recent results.
Dangerous Liouville Wave -- exactly marginal but non-conformal deformation
Chiu Man Ho; Yu Nakayama
2008-07-26
We give a non-trivially interacting field theory example of scale invariant but non-conformal field theory. The model is based on the exactly solvable Liouville field theory coupled with free scalars deformed by an exactly marginal operator. We show non-vanishing of the trace of the energy-momentum tensor by using the quantum Schwinger-Dyson equation for the Liouville field theory, which is a sophistication of the quantum higher equations of motion for the Liouville field theory introduced by Alyosha Zamolodchikov. Possibly dangerous implications for the super-critical string theory will be discussed.
Material models of dark energy
Jonathan A. Pearson
2014-09-16
We review and develop a new class of "dark energy" models, in which the relativistic theory of solids is used to construct material models of dark energy. These are models which include the effects of a continuous medium with well defined physical properties at the level of linearized perturbations. The formalism is constructed for a medium with arbitrary symmetry, and then specialised to isotropic media (which will be the case of interest for the majority of cosmological applications). We develop the theory of relativistic isotropic viscoelastic media whilst keeping in mind that we ultimately want to observationally constrain the allowed properties of the material model. We do this by obtaining the viscoelastic equations of state for perturbations (the entropy and anisotropic stress), as well as identifying the consistent corner of the theory which has constant equation of state parameter $\\dot{w}=0$. We also connect to the non-relativistic theory of solids, by identifying the two quadratic invariants that are needed to construct the energy-momentum tensor, namely the Rayleigh dissipation function and Lagrangian for perturbations. Finally, we develop the notion that the viscoelastic behavior of the medium can be thought of as a non-minimally coupled massive gravity theory. This also provides a tool-kit for constructing consistent generalizations of coupled dark energy theories.
Thermal effects in adhesive contact: modelling and analysis Elena Bonetti
Rossi, Riccarda
Thermal effects in adhesive contact: modelling and analysis Elena Bonetti , Giovanna Bonfanti , Riccarda Rossi Abstract In this paper, we consider a contact problem with adhesion between a viscoelastic equations, describing the evolution of the temperatures of the body and of the adhesive material. Our main
Structure of collective modes in transitional and deformed nuclei
M. A. Caprio
2005-03-21
The collective structure of atomic nuclei intermediate between spherical and quadrupole deformed structure presents challenges to theoretical understanding. However, models have recently been proposed in terms of potentials which are soft with respect to the quadrupole deformation variable beta. To test these models, information is needed on low-spin states of transitional nuclei. The present work involves measurement of electromagnetic decay properties of low-spin states for nuclei in the A=100 (gamma-soft) and N=90 (axially symmetric) transition regions. Population in beta-decay and thermal neutron capture are used, and measurements are carried out using gamma-ray coincidence spectroscopy, fast electronic scintillation timing, and gamma-ray induced Doppler broadening techniques, in experiments at Yale, TRIUMF ISAC, and the ILL. To facilitate interpretation of these nuclei, a new approach is developed that simplifies the application of the geometric collective model by use of scaling properties. Solutions are also obtained for the E(5) Hamiltonian for finite well depth.
Tidal deformations of a spinning compact object
Pani, Paolo; Maselli, Andrea; Ferrari, Valeria
2015-01-01
The deformability of a compact object induced by a perturbing tidal field is encoded in the tidal Love numbers, which depend sensibly on the object's internal structure. These numbers are known only for static, spherically-symmetric objects. As a first step to compute the tidal Love numbers of a spinning compact star, here we extend powerful perturbative techniques to compute the exterior geometry of a spinning object distorted by an axisymmetric tidal field to second order in the angular momentum. The spin of the object introduces couplings between electric and magnetic deformations and new classes of induced Love numbers emerge. For example, a spinning object immersed in a quadrupolar, electric tidal field can acquire some induced mass, spin, quadrupole, octupole and hexadecapole moments to second order in the spin. The deformations are encoded in a set of inhomogeneous differential equations which, remarkably, can be solved analytically in vacuum. We discuss certain subtleties in defining the multipole mom...
Plastic Deformation of 2D Crumpled Wires
M A F Gomes; V P Brito; A S O Coelho; C C Donato
2008-11-17
When a single long piece of elastic wire is injected trough channels into a confining two-dimensional cavity, a complex structure of hierarchical loops is formed. In the limit of maximum packing density, these structures are described by several scaling laws. In this paper it is investigated this packing process but using plastic wires which give origin to completely irreversible structures of different morphology. In particular, it is studied experimentally the plastic deformation from circular to oblate configurations of crumpled wires, obtained by the application of an axial strain. Among other things, it is shown that in spite of plasticity, irreversibility, and very large deformations, scaling is still observed.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Nobre, G. P. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Palumbo, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Herman, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hoblit, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Dietrich, F. S. [Walnut Creek, CA (United States)
2015-02-01
The coupled-channel theory is a natural way of treating nonelastic channels, in particular those arising from collective excitations characterized by nuclear deformations. A proper treatment of such excitations is often essential to the accurate description of experimental nuclear-reaction data and to the prediction of a wide variety of scattering observables. Stimulated by recent work substantiating the near validity of the adiabatic approximation in coupled-channel calculations for scattering on statically deformed nuclei, we explore the possibility of generalizing a global spherical optical model potential (OMP) to make it usable in coupled-channel calculations on this class of nuclei. To do this, we have deformed the Koning-Delaroche global spherical potential for neutrons, coupling a sufficient number of states of the ground state band to ensure convergence. We present an extensive study of the effects of collective couplings and nuclear deformations on integrated cross sections as well as on angular distributions for neutron-induced reactions on statically deformed nuclei in the rare-earth region. We choose isotopes of three rare-earth elements (Gd, Ho, W), which are known to be nearly perfect rotors, to exemplify the results of the proposed method. Predictions from our model for total, elastic and inelastic cross sections, as well as for elastic and inelastic angular distributions, are in reasonable agreement with measured experimental data. These results suggest that the deformed Koning-Delaroche potential provides a useful regional neutron optical potential for the statically deformed rare earth nuclei.
G. P. A. Nobre; A. Palumbo; F. S. Dietrich; M. Herman; D. Brown; S. Hoblit
2014-12-22
The coupled-channel theory is a natural way of treating nonelastic channels, in particular those arising from collective excitations characterized by nuclear deformations. A proper treatment of such excitations is often essential to the accurate description of experimental nuclear-reaction data and to the prediction of a wide variety of scattering observables. Stimulated by recent work substantiating the near validity of the adiabatic approximation in coupled-channel calculations for scattering on statically deformed nuclei, we explore the possibility of generalizing a global spherical optical model potential (OMP) to make it usable in coupled-channel calculations on this class of nuclei. To do this, we have deformed the Koning-Delaroche global spherical potential for neutrons, coupling a sufficient number of states of the ground state band to ensure convergence. We present an extensive study of the effects of collective couplings and nuclear deformations on integrated cross sections as well as on angular distributions for neutron-induced reactions on statically deformed nuclei in the rare-earth region. We choose isotopes of three rare-earth elements (Gd, Ho, W), which are known to be nearly perfect rotors, to exemplify the results of the proposed method. Predictions from our model for total, elastic and inelastic cross sections, as well as for elastic and inelastic angular distributions, are in reasonable agreement with measured experimental data. These results suggest that the deformed Koning-Delaroche potential provides a useful regional neutron optical potential for the statically deformed rare earth nuclei.
Kinematic flow patterns in slow deformation of a dense granular material
Koushik Viswanathan; Anirban Mahato; Tejas G. Murthy; Tomasz Koziara; Srinivasan Chandrasekar
2015-07-19
The kinematic flow pattern in slow deformation of a model dense granular medium is studied at high resolution using \\emph{in situ} imaging, coupled with particle tracking. The deformation configuration is indentation by a flat punch under macroscopic plane-strain conditions. Using a general analysis method, velocity gradients and deformation fields are obtained from the disordered grain arrangement, enabling flow characteristics to be quantified. The key observations are the formation of a stagnation zone, as in dilute granular flow past obstacles; occurrence of vortices in the flow immediately underneath the punch; and formation of distinct shear bands adjoining the stagnation zone. The transient and steady state stagnation zone geometry, as well as the strength of the vortices and strain rates in the shear bands, are obtained from the experimental data. All of these results are well-reproduced in exact-scale Non-Smooth Contact Dynamics (NSCD) simulations. Full 3D numerical particle positions from the simulations allow extraction of flow features that are extremely difficult to obtain from experiments. Three examples of these, namely material free surface evolution, deformation of a grain column below the punch and resolution of velocities inside the primary shear band, are highlighted. The variety of flow features observed in this model problem also illustrates the difficulty involved in formulating a complete micromechanical analytical description of the deformation.
Variation after full projection with triaxially deformed nuclear mean field
Gao, Zao-Chun; Chen, Y S
2015-01-01
We implemented a variation after projection (VAP) algorithm based on a triaxially deformed Hartree-Fock-Bogoliubov vacuum state. This is the first projected mean field study that includes all the quantum numbers (except parity), i.e., spin ($J$), isospin ($T$) and mass number ($A$). Systematic VAP calculations with $JTA$-projection have been performed for the even-even $sd$-shell nuclei with the USDB Hamiltonian. All the VAP ground state energies are within 500 keV above the exact shell model values. Our VAP calculations show that the spin projection has two important effects: (1) the spin projection is crucial in achieving good approximation of the full shell model calculation. (2) the intrinsic shapes of the VAP wavefunctions with spin projection are always triaxial, while the Hartree-Fock-Bogoliubov methods likely provide axial intrinsic shapes. Finally, our analysis suggests that one may not be possible to associate an intrinsic shape to an exact shell model wave function.
Variation after full projection with triaxially deformed nuclear mean field
Zao-Chun Gao; Mihai Horoi; Y. S. Chen
2015-09-10
We implemented a variation after projection (VAP) algorithm based on a triaxially deformed Hartree-Fock-Bogoliubov vacuum state. This is the first projected mean field study that includes all the quantum numbers (except parity), i.e., spin ($J$), isospin ($T$) and mass number ($A$). Systematic VAP calculations with $JTA$-projection have been performed for the even-even $sd$-shell nuclei with the USDB Hamiltonian. All the VAP ground state energies are within 500 keV above the exact shell model values. Our VAP calculations show that the spin projection has two important effects: (1) the spin projection is crucial in achieving good approximation of the full shell model calculation. (2) the intrinsic shapes of the VAP wavefunctions with spin projection are always triaxial, while the Hartree-Fock-Bogoliubov methods likely provide axial intrinsic shapes. Finally, our analysis suggests that one may not be possible to associate an intrinsic shape to an exact shell model wave function.
EFFECT OF GRAIN SIZE ON THE ACOUSTIC EMISSION GENERATED DURING PLASTIC DEFORMATION OF ALUMINUM
Baram, J.
2013-01-01
EMISSION GENERATED DURING PLASTIC DEFORMATION OF ALUMINUMEMISSION GENERATED DURING PLASTIC DEFORMATION OF ALUMINUM J.Al 1100 samples during plastic deformation were analyzed
PLASTIC DEFORMATION OF CRYSTALS: ANALYTICAL AND COMPUTER SIMULATION STUDIES OF DISLOCATION GLIDE
Altintas, Sabri
2011-01-01
in Rate Processes in Plastic Deformation of Materials, J. C.PLASTIC DEFORMATION OF CRYSTALS: ANALYTICAL AND COMPUTERCAPTIONS FIGURES - iii - PLASTIC DEFORMATION OF CRYSTALS:
Tidal deformations of a spinning compact object
Paolo Pani; Leonardo Gualtieri; Andrea Maselli; Valeria Ferrari
2015-06-30
The deformability of a compact object induced by a perturbing tidal field is encoded in the tidal Love numbers, which depend sensibly on the object's internal structure. These numbers are known only for static, spherically-symmetric objects. As a first step to compute the tidal Love numbers of a spinning compact star, here we extend powerful perturbative techniques to compute the exterior geometry of a spinning object distorted by an axisymmetric tidal field to second order in the angular momentum. The spin of the object introduces couplings between electric and magnetic deformations and new classes of induced Love numbers emerge. For example, a spinning object immersed in a quadrupolar, electric tidal field can acquire some induced mass, spin, quadrupole, octupole and hexadecapole moments to second order in the spin. The deformations are encoded in a set of inhomogeneous differential equations which, remarkably, can be solved analytically in vacuum. We discuss certain subtleties in defining the multipole moments of the central object, which are due to the difficulty in separating the tidal field from the linear response of the object in the solution. By extending the standard procedure to identify the linear response in the static case, we prove analytically that the Love numbers of a Kerr black hole remain zero to second order in the spin. As a by-product, we provide the explicit form for a slowly-rotating, tidally-deformed Kerr black hole to quadratic order in the spin, and discuss its geodesic and geometrical properties.
Joining of advanced materials by superplastic deformation
Goretta, Kenneth C. (Downers Grove, IL); Routbort, Jules L. (Hinsdale, IL); Gutierrez-Mora, Felipe (Woodridge, IL)
2008-08-19
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.
Deformation and Forming of Joined Materials
Carsley, John; Hovanski, Yuri; Clarke, Kester D.; Krajewski, Paul E.
2014-09-23
Introductory article to a set of invited papers from the TMS committee on shaping and forming. This paper introduces a set of papers that were prepared to discussing the deformation and forming of joined materials, and to announce an upcoming symposium at the 2015 MS&T meeting in Columbus Ohio.
Joining of advanced materials by superplastic deformation
Goretta, Kenneth C.; Routbort, Jules L.; Gutierrez-Mora, Felipe
2005-12-13
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.
Permeability Evolution during Deformation of Siliciclastic Sandstones
Permeability Evolution during Deformation of Siliciclastic Sandstones from Moab, Utah O. Kwon1 Core; 0.33-ft)- diameter cores of four sandstones from the Moab area to investigate the effect of total. Sandstones with low bulk porosities (Dewey Bridge and Slickrock Subkha) exhibited an increase in permeability
On a Model of Superconductivity and Biology
Monica De Angelis
2012-03-02
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.
Deformability of Plasmodium falciparum parasitized red blood cells
Mills, John Philip, Ph. D. Massachusetts Institute of Technology
2007-01-01
The biophysical properties of the human red blood cell (RBC) permit large deformations required for passage through narrow capillaries and spleen sinusoids. Several pathologic conditions alter RBC deformability that can ...
Low-energy collective modes of deformed superfluid nuclei within...
Office of Scientific and Technical Information (OSTI)
Low-energy collective modes of deformed superfluid nuclei within the finite-amplitude method Citation Details In-Document Search Title: Low-energy collective modes of deformed...
Steady state deformation of the Coso Range, east central California...
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...
Large deformation and electrochemistry of polyelectrolyte gels , Xuanhe Zhao b
Suo, Zhigang
Large deformation and electrochemistry of polyelectrolyte gels Wei Hong a , Xuanhe Zhao b , Zhigang. This paper develops a field theory to couple large deformation and electrochemistry. A specific material
Severe plastic deformation of difficult-to-work alloys
Yapici, Guney Guven
2004-09-30
The present work aims to reveal the microstructural evolution and post-processing mechanical behavior of difficult-to-work alloys upon severe plastic deformation. Severe plastic deformation is applied using equal channel ...
Effects of subsurface fracture interactions on surface deformation
Jerry, Ruel (Ruel Valentine)
2013-01-01
Although the surface deformation resulting from the opening of a single fracture in a layered elastic half-space resembles the observed deformation at the InSalah site, it seems unlikely that only a single fracture is ...
Lakes, Roderic
2013-01-01
old rats were used to provide an adult control, while a group of 3 month old rats provided a young but not direct loading from the exercise regimen. Twenty-four month old rats underwent one of three treadmill, no #12;investigations lend conclusive evidence of a link between old age and changes in viscoelasticity
Atomic picture of elastic deformation in a metallic glass
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Wang, X. D.; Aryal, S.; Zhong, C.; Ching, W. Y.; Sheng, H. W.; Zhang, H.; Zhang, D. X.; Cao, Q. P.; Jiang, J. Z.
2015-03-17
The tensile behavior of a Ni??Nb?? metallic glass (MG) has been studied by using ab initio density functional theory (DFT) calculation with a large cell containing 1024 atoms (614 Ni and 410 Nb). We provide insight into how a super elastic limit can be achieved in a MG. Spatially inhomogeneous responses of single atoms and also major polyhedra are found to change greatly with increasing external stress when the strain is over 2%, causing the intrinsically viscoelastic behavior. We uncover the origin of the observed super elastic strain limit under tension (including linear and viscoelastic strains) in small-sized MG samples,more »mainly caused by inhomogeneous distribution of excess volumes in the form of newly formed subatomic cavities.« less
Effects of neutron-proton interaction in doubly odd deformed nuclei
N. Itaco; A. Covello; A. Gargano
2001-03-27
We have investigated the effects of the neutron-proton interaction in several doubly odd deformed nuclei within the framework of the particle-rotor model. In this paper, we show some selected results of our study which evidence the importance of the tensor-force effects.
Large deformation and electromechanical instability of a dielectric elastomer tube actuator
Suo, Zhigang
Large deformation and electromechanical instability of a dielectric elastomer tube actuator Jian-stiffening on electromechanical behavior of DETAs by using the model of freely joined links. © 2010 American Institute of Physics thickness and expands its area. This electromechanical cou- pling was investigated for planar actuators
Permeability evolution during progressive development of deformation bands in porous sandstones
Permeability evolution during progressive development of deformation bands in porous sandstones B carried out on large (0.1 m) diameter cores of a porous sandstone in order to investigate the evolution from measured bulk parameters. In a test of the model for Clashach sandstone, the parameters vary
Rotational stability of tidally deformed planetary I. Matsuyama1
Nimmo, Francis
Rotational stability of tidally deformed planetary bodies I. Matsuyama1 and F. Nimmo2 Received 11 consider the true polar wander (rotational variations driven by mass redistribution) of tidally deformed planetary bodies. The rotation pole of bodies without tidal deformation is stabilized by the component
Non-Isothermal, Multi-phase, Multi-component Flows through Deformable Methane Hydrate Reservoirs
Gupta, Shubhangi; Wohlmuth, Barbara
2015-01-01
We present a hydro-geomechanical model for subsurface methane hydrate systems. Our model considers kinetic hydrate phase change and non-isothermal, multi-phase, multi-component flow in elastically deforming soils. The model accounts for the effects of hydrate phase change and pore pressure changes on the mechanical properties of the soil, and also for the effect of soil deformation on the fluid-solid interaction properties relevant to reaction and transport processes (e.g., permeability, capillary pressure, reaction surface area). We discuss a 'cause-effect' based decoupling strategy for the model and present our numerical discretization and solution scheme. We then identify the important model components and couplings which are most vital for a hydro-geomechanical hydrate simulator, namely, 1) dissociation kinetics, 2) hydrate phase change coupled with non-isothermal two phase two component flow, 3) two phase flow coupled with linear elasticity (poroelasticity coupling), and finally 4) hydrate phase change c...
Neutrinoless Double Beta Decay in Heavy Deformed Nuclei
Jorge G. Hirsch; O. Castaños; P. O. Hess
1994-07-12
The zero neutrino mode of the double beta decay in heavy deformed nuclei is investigated in the framework of the pseudo SU(3) model, which has provided an accurate description of collective nuclear structure and predicted half-lives for the two neutrino mode in good agreement with experiments. In the case of $^{238}U$ the calculated zero neutrino half-life is at least three orders of magnitude greater than the two neutrino one, giving strong support of the identification of the radiochemically determined half-life as being the two neutrino double beta decay. For $^{150}Nd$ the zero neutrino matrix elements are of the order of magnitude of, but lesser than, those evaluated using the QRPA. This result confirms that different nuclear models produce similar zero neutrino matrix elements, contrary to the two neutrino case. Using these pseudo SU(3) results and the upper limit for the neutrino mass we estimate the $\\beta\\beta_{0\
Earth's surface fluid variations and deformations from GPS and GRACE in global warming
Jin, Shuanggen; Feng, Guiping
2011-01-01
Global warming is affecting our Earth's environment. For example, sea level is rising with thermal expansion of water and fresh water input from the melting of continental ice sheets due to human-induced global warming. However, observing and modeling Earth's surface change has larger uncertainties in the changing rate and the scale and distribution of impacts due to the lack of direct measurements. Nowadays, the Earth observation from space provides a unique opportunity to monitor surface mass transfer and deformations related to climate change, particularly the global positioning system (GPS) and the Gravity Recovery and Climate Experiment (GRACE) with capability of estimating global land and ocean water mass. In this paper, the Earth's surface fluid variations and deformations are derived and analyzed from global GPS and GRACE measurements. The fluids loading deformation and its interaction with Earth system, e.g., Earth Rotation, are further presented and discussed.
Aharonov-Bohm interferences from local deformations in graphene
Fernando de Juan; Alberto Cortijo; María A. H. Vozmediano; Andrés Cano
2011-05-04
One of the most interesting aspects of graphene is the tied relation between structural and electronic properties. The observation of ripples in the graphene samples both free standing and on a substrate has given rise to a very active investigation around the membrane-like properties of graphene and the origin of the ripples remains as one of the most interesting open problems in the system. The interplay of structural and electronic properties is successfully described by the modelling of curvature and elastic deformations by fictitious gauge fields that have become an ex- perimental reality after the suggestion that Landau levels can form associated to strain in graphene and the subsequent experimental confirmation. Here we propose a device to detect microstresses in graphene based on a scanning-tunneling-microscopy setup able to measure Aharonov-Bohm inter- ferences at the nanometer scale. The interferences to be observed in the local density of states are created by the fictitious magnetic field associated to elastic deformations of the sample.
Biaxially textured articles formed by plastic deformation
Goyal, Amit (Knoxville, TN)
2001-01-01
A method of preparing a biaxially textured article comprises the steps of providing a metal preform, coating or laminating the preform with a metal layer, deforming the layer to a sufficient degree, and rapidly recrystallizing the layer to produce a biaxial texture. A superconducting epitaxial layer may then be deposited on the biaxial texture. In some embodiments the article further comprises buffer layers, electromagnetic devices or electro-optical devices.
A shapeable material without plastic deformation
Naomi Oppenheimer; Thomas A. Witten
2015-06-01
Randomly crumpled sheets have shape memory. In order to understand the basis of this form of memory, we simulate triangular lattices of springs whose lengths are altered to create a topography with multiple potential energy minima. We then deform these lattices into different shapes and investigate their ability to retain the imposed shape when the energy is relaxed. The lattices are able to retain a range of curvatures. Under moderate forcing from a state of local equilibrium, the lattices deform by several percent but return to their retained shape when the forces are removed. By increasing the forcing until an irreversible motion occurs, we find that the transitions between remembered shapes show co-operativity among several springs. For fixed lattice structures, the shape memory tends to decrease as the lattice is enlarged; we propose ways to counter this decrease by modifying the lattice geometry. We survey the energy landscape by displacing individual nodes. An extensive fraction of these nodes proves to be bistable; they retain their displaced position when the energy is relaxed. Bending the lattice to a stable curved state alters the pattern of bistable nodes. We discuss this shapeability in the context of other forms of material memory and contrast it with the shapeability of plastic deformation. We outline the prospects for making real materials based on these principles.
Shock wave absorber having a deformable liner
Youngdahl, C.K.; Wiedermann, A.H.; Shin, Y.W.; Kot, C.A.; Ockert, C.E.
1983-08-26
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.
Wall Adhesion and Constitutive Modelling of Strong Colloidal Gels
Daniel R. Lester; Richard Buscall; Anthony D. Stickland; Peter J. Scales
2014-06-24
Wall adhesion effects during batch sedimentation of strongly flocculated colloidal gels are commonly assumed to be negligible. In this study in-situ measurements of colloidal gel rheology and solids volume fraction distribution suggest the contrary, where significant wall adhesion effects are observed in a 110mm diameter settling column. We develop and validate a mathematical model for the equilibrium stress state in the presence of wall adhesion under both viscoplastic and viscoelastic constitutive models. These formulations highlight fundamental issues regarding the constitutive modeling of colloidal gels, specifically the relative utility and validity of viscoplastic and viscoelastic rheological models under arbitrary tensorial loadings. The developed model is validated against experimental data, which points toward a novel method to estimate the shear and compressive yield strength of strongly flocculated colloidal gels from a series of equilibrium solids volume fraction profiles over various column widths.
On constitutive modeling of soft tissue for the long-term prediction of cranio-maxillofacial
Frey, Pascal
-incompressible, nonlinear plasticviscoelastic material properties. Besides the properties well known from classic material in cranio-maxillofacial (CMF) surgery simulations. Since the biomechanical properties of living tissues and comprehensive data on material properties of a particular tissue are still very scarce. Thus, simplified models
Boundary effects on Zircaloy-4 cladding deformation in LOCA simulation tests. [PWR; BWR
Longest, A.W.; Chapman, R.H.; Crowley, J.L.
1982-01-01
Deformation behavior of Zircaloy-4 cladding under simulated loss-of-coolant accident (LOCA) conditions is being investigated in the Multirod Burst Test (MRBT) program in single rod and multirod tests. In these tests, internally-pressurized unirradiated Zircaloy-4 tubes containing internal electrical heaters are heated to failure in a low-pressure, superheated-steam environment (200 < Re < 800). The results provide a data base for evaluating deformation and blockage models employed with design-basis accident sequences to assess LWR core coolability for licensing purposes. Results of a recent 8 X 8 test indicate that models derived from smaller test arrays may not be representative of the behavior in large arrays, particularly for those temperature ranges in which large deformation can be expected. Two MRBT LOCA simulation tests conducted under the same nominal conditions (approx. 10 K/s heating rate from approx. 340/sup 0/C to failure at approx. 770/sup 0/C) were examined to determine the effects of array size and boundary conditions on deformation.
Mechanical Deformation of a Lithium-Metal Anode Due to a Very Stiff Separator
Ferrese, A; Newman, J
2014-05-21
This work builds on the two-dimensional model presented by Ferrese et al. [J. Electrochem. Soc., 159, A1615 (2012)1, which captures the movement of lithium metal at the negative electrode during cycling in a Li-metal/LiCoO2 cell. In this paper, the separator is modeled as a dendrite-inhibiting polymer separator with an elastic modulus of 16 GPa. The separator resists the movement of lithium through the generation of stresses in the cell. These stresses affect the negative electrode through two mechanisms altering the thermodynamics of the negative electrode and deforming the negative electrode mechanically. From this analysis, we find that the dendrite-inhibiting separator causes plastic and elastic deformation of the lithium at the negative electrode which flattens the electrode considerably when compared to the liquid-electrolyte case. This flattening of the negative electrode causes only very slight differences in the local state of charge in the positive electrode. When comparing the magnitude of the effects flattening the negative electrode, we find that the plastic deformation plays a much larger role than either the pressure-modified reaction kinetics or elastic deformation. This is due to the low yield strength of the lithium metal, which limits the stresses such that they have only a small effect on the reaction kinetics. (C) 2014 The Electrochemical Society. All rights reserved.
by crystal plasticity FEM Z. Zhao a , S. Kuchnicki b , R. Radovitzky a,*, A. Cuitin~o b a Department Abstract The ability of three different crystal plasticity finite element models to predict deformation. Published by Elsevier Ltd. All rights reserved. Keywords: Texture; Crystal plasticity; Finite element models
The Minimal Geometric Deformation Approach Extended
Roberto Casadio; Jorge Ovalle; Roldao da Rocha
2015-09-07
The minimal geometric deformation approach was introduced in order to study the exterior space-time around spherically symmetric self-gravitating systems, like stars or similar astrophysical objects as well, in the Randall-Sundrum brane-world framework. A consistent extension of this approach is developed here, which contains modifications of both the time component and the radial component of a spherically symmetric metric. A modified Schwarzschild geometry is obtained as an example of its simplest application, and a new solution potentially useful to describe stars in the brane-world is also presented.
Fortin, Jérôme
important processes in the oil and gas industry. Hydrocarbon production decreases the pore pressure increases. Under a relatively low effective confining pressure the differential stress attains a peak before--In some reservoirs, large deformations can occur during oil or gas production because of the effective
Overprinting Deformations in Mantle Rocks, Dun Mountain, New Zealand
Donnelly, Sara
2014-04-25
; Hansen et al., 2012a). Understanding these relationships as well as the nature of deformation in poly- and mono- mineralic rocks give insight to natural deformations in the mantle. Understanding of mantle deformation comes from coupling studies...-pyroxene formulations and argued that the thermometer developed by Taylor (1998) most accurately reproduced temperatures of laboratory experiments designed to equilibrate co-existing pyroxenes. We have applied 22 Figure 8: REE and trace element...
Flow rate--pressure drop relation for deformable shallow microfluidic...
Office of Scientific and Technical Information (OSTI)
Conference: Flow rate--pressure drop relation for deformable shallow microfluidic channels Citation Details In-Document Search Title: Flow rate--pressure drop relation for...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
crystals), individual crystals deform preferentially along slip planes. This results in crystal rotations that lead to crystallographic preferred orientation ("texture") in the...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
its interior to the surface via convection. Convection not only manifests itself in the plastic deformation of mineral phases due to stress, but it also drives plate tectonics....
Resonant states of deformed nuclei in complex scaling method
Quan Liu; Jian-You Guo; Zhong-Ming Niu; Shou-Wan Chen
2012-11-29
We develop a complex scaling method for describing the resonances of deformed nuclei and present a theoretical formalism for the bound and resonant states on the same footing. With $^{31}$Ne as an illustrated example, we have demonstrated the utility and applicability of the extended method and have calculated the energies and widths of low-lying neutron resonances in $^{31}$Ne. The bound and resonant levels in the deformed potential are in full agreement with those from the multichannel scattering approach. The width of the two lowest-lying resonant states shows a novel evolution with deformation and supports an explanation of the deformed halo for $^{31}$Ne.
The effect of nuclear deformation on level statistics
A. Al-Sayed
2009-03-01
We analyze the nearest neighbor spacing distributions of low-lying 2+ levels of even-even nuclei. We grouped the nuclei into classes defined by the quadrupole deformation parameter (Beta2). We calculate the nearest neighbor spacing distributions for each class. Then, we determine the chaoticity parameter for each class with the help of the Bayesian inference method. We compare these distributions to a formula that describes the transition to chaos by varying a tuning parameter. This parameter appears to depend in a non-trivial way on the nuclear deformation, and takes small values indicating regularity in strongly deformed nuclei and especially in those having an oblate deformation.
Cell Motility and Deformability in the Pathogenesis of Lung Cancer
Pagano, Paul Carmelo
2015-01-01
tumor-initiating cells (TICs), cells capable of repopulatingby deformability and analyzed for TIC properties, includingdeformability relates to the TIC phenotype and how they
Ruthenium Aluminides: Deformation Mechanisms and Substructure Development
Tresa M. Pollock
2005-05-11
Structural and functional materials that can operate in severe, high temperature environments are key to the operation of a wide range of energy generation systems. Because continued improvements in the energy efficiency of these systems is critical, the need for new materials with higher temperature capabilities is inevitable. Intermetallic compounds, with strong bonding and generally high melting points offer this possibility for a broad array of components such as coatings, electrode materials, actuators and/or structural elements. RuAl is a very unusual intermetallic compound among the large number of B2compounds that have been identified and investigated to date. This material has a very high melting temperature of 2050?C, low thermal expansion, high thermal conductivity and good corrosion resistance. Unlike most other high temperature B2 intermetallics, RuAl possesses good intrinsic deformability at low temperatures. In this program fundamental aspects of low and high temperature mechanical properties and deformation mechanisms in binary and higher order RuAl-based systems have been investigated. Alloying additions of interest included platinum, boron and niobium. Additionally, preliminary studies on high temperature oxidation behavior of these materials have been conducted.
Primordial fluctuations from deformed quantum algebras
Day, Andrew C. [Department of Applied Mathematics, University of Western Ontario London, ON, Canada N6A 5B7 (Canada); Brown, Iain A. [Institute of Theoretical Astrophysics, University of Oslo P.O. Box 1029 Blindern, N-0315 Oslo (Norway); Seahra, Sanjeev S., E-mail: aday46@uwo.ca, E-mail: ibrown@astro.uio.no, E-mail: sseahra@unb.ca [Department of Mathematics and Statistics, University of New Brunswick Fredericton, NB, Canada E3B 5A3 (Canada)
2014-03-01
We study the implications of deformed quantum algebras for the generation of primordial perturbations from slow-roll inflation. Specifically, we assume that the quantum commutator of the inflaton's amplitude and momentum in Fourier space gets modified at energies above some threshold M{sub *}. We show that when the commutator is modified to be a function of the momentum only, the problem of solving for the post-inflationary spectrum of fluctuations is formally equivalent to solving a one-dimensional Schr and quot;odinger equation with a time dependent potential. Depending on the class of modification, we find results either close to or significantly different from nearly scale invariant spectra. For the former case, the power spectrum is characterized by step-like behaviour at some pivot scale, where the magnitude of the jump is O(H{sup 2}/M{sub *}{sup 2}). (H is the inflationary Hubble parameter.) We use our calculated power spectra to generate predictions for the cosmic microwave background and baryon acoustic oscillations, hence demonstrating that certain types of deformations are incompatible with current observations.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Nobre, G. P. A.; Palumbo, A.; Herman, M.; Brown, D.; Hoblit, S.; Dietrich, F. S.
2015-02-25
The coupled-channel theory is a natural way of treating nonelastic channels, in particular those arising from collective excitations characterized by nuclear deformations. A proper treatment of such excitations is often essential to the accurate description of experimental nuclear-reaction data and to the prediction of a wide variety of scattering observables. Stimulated by recent work substantiating the near validity of the adiabatic approximation in coupled-channel calculations for scattering on statically deformed nuclei, we explore the possibility of generalizing a global spherical optical model potential (OMP) to make it usable in coupled-channel calculations on this class of nuclei. To do this, wemore »have deformed the Koning-Delaroche global spherical potential for neutrons, coupling a sufficient number of states of the ground state band to ensure convergence. We present an extensive study of the effects of collective couplings and nuclear deformations on integrated cross sections as well as on angular distributions for neutron-induced reactions on statically deformed nuclei in the rare-earth region. We choose isotopes of three rare-earth elements (Gd, Ho, W), which are known to be nearly perfect rotors, to exemplify the results of the proposed method. Predictions from our model for total, elastic and inelastic cross sections, as well as for elastic and inelastic angular distributions, are in reasonable agreement with measured experimental data. In conclusion, these results suggest that the deformed Koning-Delaroche potential provides a useful regional neutron optical potential for the statically deformed rare earth nuclei.« less
Type-IV Pilus Deformation Can Explain Retraction Behavior
Ranajay Ghosh; Aloke Kumar; Ashkan Vaziri
2014-09-18
Polymeric filament like type IV Pilus (TFP) can transfer forces in excess of 100pN during their retraction before stalling, powering surface translocation(twitching). Single TFP level experiments have shown remarkable nonlinearity in the retraction behavior influenced by the external load as well as levels of PilT molecular motor protein. This includes reversal of motion near stall forces when the concentration of the PilT protein is lowered significantly. In order to explain this behavior, we analyze the coupling of TFP elasticity and interfacial behavior with PilT kinetics. We model retraction as reaction controlled and elongation as transport controlled process. The reaction rates vary with TFP deformation which is modeled as a compound elastic body consisting of multiple helical strands under axial load. Elongation is controlled by monomer transport which suffer entrapment due to excess PilT in the cell periplasm. Our analysis shows excellent agreement with a host of experimental observations and we present a possible biophysical relevance of model parameters through a mechano-chemical stall force map
Theodore E. Liolios
2000-08-13
Thermonuclear fusion reaction rates in the solar plasma are enhanced by the presence of the electron cloud that screens fusing nuclei. The present work studies the influence of electron screening deformations on solar reaction rates in the framework of the Debye-Huckel model. These electron-ion cloud deformations, assumed here to be static and axially symmetric, are shown to be able to considerably influence the solar neutrino fluxes of the pp and the CNO chains, with reasonable changes in the macroscopic parameters of the standard solar model (SSM) . Various known deformation sources are discussed but none of them is found strong enough to have a significant impact on the SSM neutrino fluxes.
Contractional deformation of porous sandstone: Insights from the Aztec Sandstone, SE Nevada, USA
Fossen, Haakon
Contractional deformation of porous sandstone: Insights from the Aztec Sandstone, SE Nevada, USA Available online 19 March 2015 Keywords: Sevier thrusting Porous sandstone deformation Deformation bands Contractional deformation a b s t r a c t Contractional deformation of highly porous sandstones is poorly
Platform Deformation Refined Pointing and Phase Correction for the AMiBA Hexapod Telescope
Koch, Patrick M; Chang, Yu-Yen; Huang, Yau-De; Raffin, Philippe; Chen, Ke-Yung; Chereau, Guillaume; Chen, Ming-Tang; Ho, Paul T P; Huang, Chih-Wie; Ibanez-Romano, Fabiola; Jiang, Homin; Liao, Yu-Wei; Lin, Kai-Yang; Liu, Guo-Chin; Molnar, Sandor M; Nishioka, Hiroaki; Umetsu, Keiichi; Wang, Fu-Cheng; Wu, Jiun-Huei Proty; Altamirano, Pablo; Chang, Chia-Hao; Chang, Shu-Hao; Chang, Su-Wei; Han, Chi-Chiang; Kubo, Derek; Li, Chao-Te; Martin-Cocher, Pierre; Oshiro, Peter
2009-01-01
The Array for Microwave Background Anisotropy (AMiBA) is a radio interferometer for research in cosmology, currently operating 7 0.6m diameter antennas co-mounted on a 6m diameter platform driven by a hexapod mount. AMiBA is currently the largest hexapod telescope. We briefly summarize the hexapod operation with the current pointing error model. We then focus on the upcoming 13-element expansion with its potential difficulties and solutions. Photogrammetry measurements of the platform reveal deformations at a level which can affect the optical pointing and the receiver radio phase. In order to prepare for the 13-element upgrade, two optical telescopes are installed on the platform to correlate optical pointing tests. Being mounted on different locations, the residuals of the two sets of pointing errors show a characteristic phase and amplitude difference as a function of the platform deformation pattern. These results depend on the telescope's azimuth, elevation and polarization position. An analytical model ...
Chen, Kai; Advanced Light Source; UCLA
2008-01-01
Plastic deformation in Al (Cu) interconnects stressed bygrain orientation [7], study plastic deformation [12-15] andThis aspect of EM-induced plastic deformation in grains
An experimental study on grain deformation and interactions in an
Tong, Wei
deformation; B. Crystal plasticity International Journal of Plasticity 20 (2004) 523542 www knowledge on the plasticity of single crystals, the plastic deformation behavior of a polycrystalline of crystal plasticity while the computational costs are increasingly affordable (Barbe et al., 2001; Goh et
Local Deformations of Polymers with Nonplanar Rigid Main-Chain
Dinner, Aaron
Local Deformations of Polymers with Nonplanar Rigid Main-Chain Internal Coordinates AARON R. DINNER: A procedure for local deformation of a polymer by concerted rotation of several main-chain dihedral angles has of an RNA hairpin loop in which the main chain (C3 --C4 ) bonds that are constrained by the sugar rings
Micrographic detection of plastic deformation in nickel base alloys
Steeves, Arthur F. (Schenectady, NY); Bibb, Albert E. (Clifton Park, NY)
1984-01-01
A method for detecting low levels of plastic deformation in metal articles comprising electrolytically etching a flow free surface of the metal article with nital at a current density of less than about 0.1 amp/cm.sup.2 and microscopically examining the etched surface to determine the presence of alternating striations. The presence of striations indicates plastic deformation in the article.
Medially Based Meshing with Finite Element Analysis of Prostate Deformation
Crouch, Jessica R.
Medially Based Meshing with Finite Element Analysis of Prostate Deformation Jessica R. Crouch1 have approached prostate imaging problems using meth- ods that incorporate finite element analysis. Assume the prostate is a linearly elastic body and compute its deformation using finite element analysis
Large Deformation of Nitinol Under Shear Dominant Loading
Bhattacharya, Kaushik
Large Deformation of Nitinol Under Shear Dominant Loading S. Daly & D. Rittel & K. Bhattacharya & G Abstract Full-field quantitative strain maps of phase transformation and plasticity in Nitinol under large that is seen in uniaxial testing. The shear-dominant deformation of Nitinol in the plastic regime exhibits low
Characterisation of severely deformed austenitic stainless steel wire
Cambridge, University of
. Experimental procedure Stainless steel (316L) wires with 190 mm diameter in the annealed state are usedCharacterisation of severely deformed austenitic stainless steel wire H. S. Wang1 , J. R. Yang1 of 316L austenitic stainless steel has been examined using TEM and X-ray diffraction. The deformation
DEFORMATION OF THE HURRICANE MOUNTAIN FORMATION MELANGE ALONG TOMHEGAN AND
Beane, Rachel J.
DEFORMATION OF THE HURRICANE MOUNTAIN FORMATION MELANGE ALONG TOMHEGAN AND COLD STREAMS, WEST through Acadian deformation recorded in foliated pelites of the Hurricane Mountain Formation in west central Maine. The Hurricane Mountain Formation is a melange with a grey sulfidic slate- to gneiss- matrix
Master Thesis Phase-field Modeling of
Cambridge, University of
University of Science and Technology 2010 #12;II Phase-field Modeling of Crystal Growth during-field Modeling of Crystal Growth during Deformation Department of Ferrous Technology (Computational MetallurgyI Master Thesis Phase-field Modeling of Crystal Growth during Deformation Tan Xu
Representation Theory of Generalized Deformed Oscillator Algebras
C. Quesne; N. Vansteenkiste
1997-01-28
The representation theory of the generalized deformed oscillator algebras (GDOA's) is developed. GDOA's are generated by the four operators ${1,a,a^{\\dag},N}$. Their commutators and Hermiticity properties are those of the boson oscillator algebra, except for $[a, a^{\\dag}]_q = G(N)$, where $[a,b]_q = a b - q b a$ and $G(N)$ is a Hermitian, analytic function. The unitary irreductible representations are obtained by means of a Casimir operator $C$ and the semi-positive operator $a^{\\dag} a$. They may belong to one out of four classes: bounded from below (BFB), bounded from above (BFA), finite-dimentional (FD), unbounded (UB). Some examples of these different types of unirreps are given.
High stroke pixel for a deformable mirror
Miles, Robin R.; Papavasiliou, Alexandros P.
2005-09-20
A mirror pixel that can be fabricated using standard MEMS methods for a deformable mirror. The pixel is electrostatically actuated and is capable of the high deflections needed for spaced-based mirror applications. In one embodiment, the mirror comprises three layers, a top or mirror layer, a middle layer which consists of flexures, and a comb drive layer, with the flexures of the middle layer attached to the mirror layer and to the comb drive layer. The comb drives are attached to a frame via spring flexures. A number of these mirror pixels can be used to construct a large mirror assembly. The actuator for the mirror pixel may be configured as a crenellated beam with one end fixedly secured, or configured as a scissor jack. The mirror pixels may be used in various applications requiring high stroke adaptive optics.
Neutron shell structure and deformation in neutron-drip-line nuclei
Ikuko Hamamoto
2012-06-18
Neutron shell-structure and the resulting possible deformation in the neighborhood of neutron-drip-line nuclei are systematically discussed, based on both bound and resonant neutron one-particle energies obtained from spherical and deformed Woods-Saxon potentials. Due to the unique behavior of weakly-bound and resonant neutron one-particle levels with smaller orbital angular-momenta $\\ell$, a systematic change of the shell structure and thereby the change of neutron magic-numbers are pointed out, compared with those of stable nuclei expected from the conventional j-j shell-model. For spherical shape with the operator of the spin-orbit potential conventionally used, the $\\ell_{j}$ levels belonging to a given oscillator major shell with parallel spin- and orbital-angular-momenta tend to gather together in the energetically lower half of the major shell, while those levels with anti-parallel spin- and orbital-angular-momenta gather in the upper half. The tendency leads to a unique shell structure and possible deformation when neutrons start to occupy the orbits in the lower half of the major shell. Among others, the neutron magic-number N=28 disappears and N=50 may disappear, while the magic number N=82 may presumably survive due to the large $\\ell =5$ spin-orbit splitting for the $1h_{11/2}$ orbit. On the other hand, an appreciable amount of energy gap may appear at N=16 and 40 for spherical shape, while neutron-drip-line nuclei in the region of neutron number above N=20, 40 and 82, namely N $\\approx$ 21-28, N $\\approx$ 41-54, and N $\\approx$ 83-90, may be quadrupole-deformed though the possible deformation depends also on the proton number of respective nuclei.
Deformed quantum double realization of the toric code and beyond
Pramod Padmanabhan; Juan Pablo Ibieta Jimenez; Miguel Jorge Bernabé Ferreira; Paulo Teotonio-Sobrinho
2015-12-10
Quantum double models, such as the toric code, can be constructed from transfer matrices of lattice gauge theories with discrete gauge groups and parametrized by the center of the gauge group algebra and its dual. For general choices of these parameters the transfer matrix contains operators acting on links which can also be thought of as perturbations to the quantum double model driving it out of its topological phase and destroying the exact solvability of the quantum double model. We modify these transfer matrices with perturbations and extract exactly solvable models which remain in a quantum phase, thus nullifying the effect of the perturbation. The algebra of the modified vertex and plaquette operators now obey a deformed version of the quantum double algebra. The Abelian cases are shown to be in the quantum double phase whereas the non-Abelian phases are shown to be in a modified phase of the corresponding quantum double phase. These are illustrated with the groups $\\mathbb{Z}_n$ and $S_3$. The quantum phases are determined by studying the excitations of these systems namely their fusion rules and the statistics. We then go further to construct a transfer matrix which contains the other $\\mathbb{Z}_2$ phase namely the double semion phase. More generally for other discrete groups these transfer matrices contain the twisted quantum double models. These transfer matrices can be thought of as being obtained by introducing extra parameters into the transfer matrix of lattice gauge theories. These parameters are central elements belonging to the tensor products of the algebra and its dual and are associated to vertices and volumes of the three dimensional lattice. As in the case of the lattice gauge theories we construct the operators creating the excitations in this case and study their braiding and fusion properties.
EFFECT OF GRAIN SIZE ON THE ACOUSTIC EMISSION GENERATED DURING PLASTIC DEFORMATION OF COPPER
Baram, J.
2011-01-01
but only after some extent of plastic deformation, It can,The Inhomogeneity of Plastic Deformation, A.S.M. Seminar,EMISSION GENERATED DURING PLASTIC DEFORMATION OF COPPER J,
Fossen, Haakon
localization structures in porous sandstones, known as deformation bands, are reported to perturb functions to estimate the porosity and specific surface area in deformed sandstones from high anisotropy with regard to petrophysical properties in deformed sandstones, and demonstrated variations
Interfacial deformation and jetting of a magnetic fluid
Afkhami, Shahriar; Griffiths, Ian M
2015-01-01
An attractive technique for forming and collecting aggregates of magnetic material at a liquid--air interface by an applied magnetic field gradient was recently addressed theoretically and experimentally [Soft Matter, (9) 2013, 8600-8608]: when the magnetic field is weak, the deflection of the liquid--air interface has a steady shape, while for sufficiently strong fields, the interface destabilizes and forms a jet that extracts magnetic material. Motivated by this work, we develop a numerical model for the closely related problem of solving two-phase Navier--Stokes equations coupled with the static Maxwell equations. We computationally model the forces generated by a magnetic field gradient produced by a permanent magnet and so determine the interfacial deflection of a magnetic fluid (a pure ferrofluid system) and the transition into a jet. We analyze the shape of the liquid--air interface during the deformation stage and the critical magnet distance for which the static interface transitions into a jet. We d...
Devincre, Benoit
Dislocation-dynamics based crystal plasticity law for the low- and high-temperature deformation; bcc; Crystal plasticity; Thermal activation 1. Introduction Crystal plasticity modeling at the level regimes of bcc crystal Ghiath Monnet a, , Ludovic Vincent b , Benoit Devincre c a EDF R&D, MMC, avenue
Ling, Phyllis
2000-01-01
During embryonic development, the heart undergoes remarkable morphological changes due to genetic programming and epigenetic influences such as mechanical loads. L.A. Taber and colleagues at Washington University have proposed mathematical models...
Modeling Of Surface Deformation From Satellite Radar Interferometry In The
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STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS
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Modeling fluid flow in deformation bands with stabilized localization mixed
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STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS
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A new multilayered visco-elasto-plastic experimental model to study strike-slip
Cattin, Rodolphe
between kinematic and mechanical parameters, we have developed a new experimental approach allowing, results show that the model succeed in reproducing the deformation mechanisms and surface kinematics analysis of surface deformation associated with active fault seismic cycle. However, the study
Time-aging time-stress superposition in soft glass under tensile deformation field
Asima Shaukat; Ashutosh Sharma; Yogesh M. Joshi
2010-06-10
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.
Neutrinoless double-{beta} decay of {sup 150}Nd accounting for deformation
Fang Dongliang; Faessler, Amand; Rodin, Vadim; Simkovic, Fedor [Institut fuer Theoretische Physik, Universitaet Tuebingen, D-72076 Tuebingen (Germany); BLTP, JINR, Dubna (Russian Federation) and Department of Nuclear Physics, Comenius University, SK-842 15 Bratislava (Slovakia)
2010-11-15
A microscopic state-of-the-art calculation of the nuclear matrix element for neutrinoless double-{beta} decay of {sup 150}Nd with an account for nuclear deformation is performed. The proton-neutron quasiparticle random phase approximation (QRPA) with a realistic residual interaction [the Brueckner G matrix derived from the charge-dependent Bonn (Bonn-CD) nucleon-nucleon potential] is used as the underlying nuclear structure model. The present calculated matrix element is suppressed by about 40% as compared with our previous QRPA result for {sup 150}Nd obtained with neglect of deformation. By making use of this newest nuclear matrix element, one may conclude that neutrinoless double-{beta} decay of {sup 150}Nd, to be measured soon by the SNO+ collaboration, provides one of the best probes of the Majorana neutrino mass.
Neutrinoless double beta decay of $^{150}$Nd with account for deformation
Dong-Liang Fang; Amand Faessler; Vadim Rodin; Fedor Simkovic
2010-11-02
A microscopic state-of-the-art calculation of the nuclear matrix element for neutrinoless double beta decay of $^{150}$Nd with an account for nuclear deformation is performed. The proton-neutron quasiparticle random phase approximation (QRPA) with a realistic residual interaction [the Brueckner $G$ matrix derived from the charge-depending Bonn (Bonn-CD) nucleon-nucleon potential] is used as the underlying nuclear structure model. The present calculated matrix element is suppressed by about 40% as compared with our previous QRPA result for $^{150}$Nd obtained with neglect of deformation. By making use of this newest nuclear matrix element, one may conclude that neutrinoless double beta decay of $^{150}$Nd, to be measured soon by the SNO+ collaboration, provides one of the best probes of the Majorana neutrino mass.
Tsibidis, G. D.; Stratakis, E.; Aifantis, K. E.
2012-03-01
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.
Perspectives on the viscoelasticity and flow behavior of entangled linear and branched polymers
Snijkers, F; Olmsted, P D; Vlassopoulos, D
2015-01-01
We briefly review the recent advances in the rheology of entangled polymers and identify emerging research trends and outstanding challenges, especially with respect to branched polymers. Emphasis is placed on the role of well-characterized model systems, as well as the synergy of synthesis-characterization, rheometry and modeling/simulations. The theoretical framework for understanding the observed linear and nonlinear rheological phenomena is the tube model which is critically assessed in view of its successes and shortcomings, whereas alternative approaches are briefly discussed. Finally, intriguing experimental findings and controversial issues that merit consistent explanation, such as shear banding instabilities, multiple stress overshoots in transient simple shear and enhanced steady-state elongational viscosity in polymer solutions, are discussed, whereas future directions such as branch point dynamics and anisotropic monomeric friction are outlined.
Lauricella, Marco; Coluzza, Ivan; Pisignano, Dario; Succi, Sauro
2015-01-01
We investigate the effects of dissipative air drag on the dynamics of electrified jets in the early stage of the electrospinning process. The main idea is to use a Brownian noise to model air drag effects on the uniaxial elongation of the jets. The numerical model is used to probe the dynamics of electrified polymer jets at different conditions of air drag force. Numerical simulations show that the elongation of the charged jet filament is significantly affected by the presence of air drag force, providing prospective beneficial implications for the optimal design of future electrospinning experiments.
Marco Lauricella; Giuseppe Pontrelli; Ivan Coluzza; Dario Pisignano; Sauro Succi
2015-07-01
We investigate the effects of dissipative air drag on the dynamics of electrified jets in the initial stage of the electrospinning process. The main idea is to use a Brownian noise to model air drag effects on the uniaxial elongation of the jets. The developed numerical model is used to probe the dynamics of electrified polymer jets at different conditions of air drag force, showing that the dynamics of the charged jet is strongly biased by the presence of air drag forces. This study provides prospective beneficial implications for improving forthcoming electrospinning experiments.
Berlyand, Leonid
). Such polymer compounds (e.g., carbon black or silica particles in a polymer matrix) are widely used in industry by an attempt to develop a rigorous mathematical model of polymer compounds highly filled with a large number and their properties have been subject of studies in polymer science and engineering literature (see, for example
Jeon, Jaehyeuk
2013-08-09
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...
Deformed Gaussian Orthogonal Ensemble description of Small-World networks
J. X. de Carvalho; Sarika Jalan; M. S. Hussein
2009-04-25
The study of spectral behavior of networks has gained enthusiasm over the last few years. In particular, Random Matrix Theory (RMT) concepts have proven to be useful. In discussing transition from regular behavior to fully chaotic behavior it has been found that an extrapolation formula of the Brody type can be used. In the present paper we analyze the regular to chaotic behavior of Small World (SW) networks using an extension of the Gaussian Orthogonal Ensemble. This RMT ensemble, coined the Deformed Gaussian Orthogonal Ensemble (DGOE), supplies a natural foundation of the Brody formula. SW networks follow GOE statistics till certain range of eigenvalues correlations depending upon the strength of random connections. We show that for these regimes of SW networks where spectral correlations do not follow GOE beyond certain range, DGOE statistics models the correlations very well. The analysis performed in this paper proves the utility of the DGOE in network physics, as much as it has been useful in other physical systems.
Activation of conductive pathways via deformation-induced instabilities
Ni, Xinchen
2014-01-01
Inspired by the pattern transformation of periodic elastomeric cellular structures, the purpose of this work is to exploit this unique ability to activate conductive via deformation-induced instabilities. Two microstructural ...
Origin and deformation of Holocene shoreline terraces, Yellowstone Lake, Wyoming
Meyer, G.A.; Locke, W.W.
1986-08-01
Geodetic surveys within the Yellowstone caldera have documented active uplift that is most likely caused by magmatic processes in the upper crust. Along the northeast shore of Yellowstone Lake, maximum relative uplift rates are 10 mm/yr for the period 1923-1975. However, information on deformation prior to historic instrumental records has been lacking. In this study, closely spaced data on elevations of postglacial shoreline terraces around the north end of Yellowstone Lake reveal complex tilting. Though most Holocene deformation is probably magma related, the pattern of shoreline tilting deviates significantly from the historic pattern of roughly symmetric inflation of the caldera. Along the northeast shore, where tilt directions of historic and shoreline deformation are similar, differential uplift of a > 2500-yr-old terrace is roughly 10 m; this gives a maximum uplift rate of 4 mm/yr. These unique Holocene terraces may exist due to episodic deformation because vertical movements affecting the lake outlet directly control lake level.
Applications of Slattery - Lagoudas' theory for the stress deformation behavior
Tian, Yongzhe
2006-10-30
The thermodynamics of three-dimensional, single-component elastic crystalline solids was developed by Slattery and Lagoudas (2005). Considering the inÃ?Â¯nitesimal deformations, the stress can be expressed as a function of the lattice vectors...
Self-sorting of deformable particles in a microfluidic circuit
Raafat, Mohamed Salem
2010-01-01
In this thesis, a new microfluidic device is presented for sorting of deformable particles based on the hydrodynamic resistance induced in a microchannel. Hydrodynamic resistance can be related to physical properties, ...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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...
Mechanics of inelastic deformation and delamination in paperboard
Xia, Qingxi, 1973-
2002-01-01
Paperboard is one of the most widely used materials. The inelastic deformation of paperboard plays a crucial role during many manufacturing processes (e.g., the converting process whereby paperboard is converted into a ...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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...
3D deformation field throughout the interior of materials.
Jin, Huiqing; Lu, Wei-Yang
2013-09-01
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.
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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...
Wavefront control in space with MEMS deformable mirrors
Cahoy, Kerri
To meet the high contrast requirement of 1 × 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) ...
Seismic tomography and surface deformation in Krýsuvík, SW Iceland
Lu, Jing, S.M. Massachusetts Institute of Technology
2013-01-01
The Krýsuvík region of southwestern Iceland is a region of high potential for geothermal energy that is currently experiencing seismic swarm activity and active surface deformation. Understanding the subsurface structure ...
Effect of nuclear deformation on double beta decay
Rodin, Vadim [Institute fuer Theoretische Physik der Universitaet Tuebingen, D-72076 Tuebingen (Germany)
2009-11-09
The existing ways of accounting for deformation in recent calculations of neutrinoless double beta decay matrix elements are discussed. From an analysis of relevant experimental data it is argued that only {sup 150}Nd reveals convincing evidences of strong static deformation, which should eventually be taken into account in QRPA calculations. A proposal which allows in principle to measure the neutrino less double beta decay Fermi matrix element is briefly described.
Structure and deformation mechanisms along the Tonale Line, n. Italy
Welker, Mary Clare
1985-01-01
of brittle and ductile deformation and for evidence of pore fluids. Synthesis of the field relationships, compositional and petrofabric analyses were carried out to characterize the overall structure, deformation mechanisms and mechanical behavior... whole were leveled down to a chain of fairly low hill s (Tr'umpy, 1973). Currently, the Tonale Line shows no movement, and it is seismically inactive. Both vertical and horizontal displacements are recognized along the fault, most likely from...
Experimental deformation of multilithologic specimens simulating sedimentary facies changes
Dyke, Lawrence Dana
1976-01-01
EXPERIMENTAL DEFORMATION OF MULTILITHOLOGIC SPECIMENS SIMULATING SEDIMENTARY FACIES CHANGES A Thesis by LAWRENCE DANA DYKE Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1976 Major Subject: Geology EXPERIMENTAL DEFORMATION OF MULTILITHOLOGIC SPECIMENS SIMULATING SEDIMENTARY FACIES CHANGES A Thesis by LAWRENCE DANA DYKE Approved as to style and content by: (Chai n Committee) (Head...
TDHF fusion calculations for spherical+deformed systems
A. S. Umar; V. E. Oberacker
2006-04-04
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.
Angularly Deformed Special Relativity and its Results for Quantum Mechanics
Lukasz Andrzej Glinka
2015-09-15
In this paper, the deformed Special Relativity, which leads to an essentially new theoretical context of quantum mechanics, is presented. The formulation of the theory arises from a straightforward analogy with the Special Relativity, but its foundations are laid through the hypothesis on breakdown of the velocity-momentum parallelism which affects onto the Einstein equivalence principle between mass and energy of a relativistic particle. Furthermore, the derivation is based on the technique of an eikonal equation whose well-confirmed physical role lays the foundations of both optics and quantum mechanics. As a result, we receive the angular deformation of Special Relativity which clearly depicts the new deformation-based theoretical foundations of physics, and, moreover, offers both constructive and consistent phenomenological discussion of the theoretical issues such like imaginary mass and formal superluminal motion predicted in Special Relativity for this case. In the context of the relativistic theory, presence of deformation does not break the Poincar\\'{e} invariance, in particular the Lorentz symmetry, and provides essential modifications of both bosons described through the Klein-Gordon equation and fermions satisfying the Dirac equation. On the other hand, on the level of discussion of quantum theory, there arises the concept of emergent deformed space-time, wherein the presence of angular deformation elucidates a certain new insight into the nature of spin, as well as both the Heisenberg uncertainty principle and the Schr\\"odinger wave equation.
Van Vliet, Krystyn J.
Size effects on the onset of plastic deformation during nanoindentation of thin films and patterned; accepted 13 August 2003 Plastic deformation of materials exhibits a strong size dependence when, particularly the transition from elastic to plastic deformation and the early stages of plastic deformation. We
Napieralski, A
2005-01-01
Application Of Multilayer Piezoelectric Elements For Resonant Cavity Deformation In VUV-FEL DESY Accelerator
Surface Dynamic Deformation Estimates From Seismicity Near the Itoiz Reservoir, Northern Spain
Santoyo, Miguel A; García-Jerez, Antonio; Luzón, Francisco
2014-01-01
We analyzed the ground motion time histories due to the local seismicity near the Itoiz reservoir, in order to estimate the surface 3D displacement-gradients and dynamic deformations. The seismic data were obtained by a semi-permanent broadband and accelerometric network installed by the University of Almeria during 2008 and 2009. Seismic sensors were located on surface and at underground sites in the vicinity of the dam. The dynamic deformation field was calculated by two different methods. On one hand, by the Seismo-Geodetic method using the data from a three-station micro-array. On the other hand, by Single-Station estimates of displacement gradients, assuming the incidence of body wave fields propagating through the recording site. The dynamic deformations obtained from both methods were compared and analyzed in the context of the local effects near the dam. The shallow 1D velocity structure was estimated from seismic data by modeling the body-wave travel times. After the comparison of the dynamic displac...
Numerical study of the stress state of a deformation twin in magnesium
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Arul Kumar, M.; Kanjarla, A. K.; Niezgoda, S. R.; Lebensohn, R. A.; Tomé, C. N.
2014-11-26
Here, we present a numerical study of the distribution of the local stress state associated with deformation twinning in Mg, both inside the twinned domain and in its immediate neighborhood, due to the accommodation of the twinning transformation shear. A full-field elastoviscoplastic formulation based on fast Fourier transformation is modified to include the shear transformation strain associated with deformation twinning. We performed two types of twinning transformation simulations with: (i) the twin completely embedded inside a single crystal and (ii) the twin front terminating at a grain boundary. We show that: (a) the resulting stress distribution is more strongly determinedmore »by the shear transformation than by the intragranular character of the twin or the orientation of the neighboring grain; (b) the resolved shear stress on the twin plane along the twin direction is inhomogeneous along the twin–parent interface; and (c) there are substantial differences in the average values of the shear stress in the twin and in the parent grain that contains the twin. We discuss the effect of these local stresses on twin propagation and growth, and the implications of our findings for the modeling of deformation twinning.« less
Bohr Hamiltonian with a deformation-dependent mass term: physical meaning of the free parameter
Dennis Bonatsos; N. Minkov; D. Petrellis
2015-06-24
Embedding of the 5-dimensional (5D) space of the Bohr Hamiltonian with a deformation-dependent mass (DDM) into a 6-dimensional (6D) space shows that the free parameter in the dependence of the mass on the deformation is connected to the curvature of the 5D space, with the special case of constant mass corresponding to a flat 5D space. Comparison of the DDM Bohr Hamiltonian to the 5D classical limit of Hamiltonians of the 6D interacting boson model (IBM), shows that the DDM parameter is proportional to the strength of the pairing interaction in the U(5) (vibrational) symmetry limit, while it is proportional to the quadrupole-quadrupole interaction in the SU(3) (rotational) symmetry limit, and to the difference of the pairing interactions among s, d bosons and d bosons alone in the O(6) (gamma-soft) limit. The presence of these interactions leads to a curved 5D space in the classical limit of IBM, in contrast to the flat 5D space of the original Bohr Hamiltonian, which is made curved by the introduction of the deformation-dependent mass.
Computational Modeling of Self-organization of Dislocations and...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Computational Modeling of Self-organization of Dislocations and Mesoscale Deformation of Metals Event Sponsor: Mathematics and Computing Science - LANS Seminar Start Date: Jun 19...
Modeling-Computer Simulations At Long Valley Caldera Geothermal...
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...
Modeling-Computer Simulations At Long Valley Caldera Geothermal...
and seismic data was conducted in 2003 to investigate the cause of recent uplift of the resurgent dome. Notes Modeling of deformation and microgravity data suggests...
The enigma of post-perovskite anisotropy: deformation versus transformation textures
Miyagi, Lowell; Kanitpanyacharoen, Waruntorn; Stackhouse, Stephen; Militzer, Burkhard; Wenk, Hans-Rudolf
2012-01-20
The D'' region that lies just above the core mantle boundary exhibits complex anisotropy that this is likely due to preferred orientation (texturing) of the constituent minerals. (Mg,Fe)SiO{sub 3} post-perovskite is widely thought to be the major mineral phase of the D''. Texture development has been studied in various post-perovskite phases (MgSiO{sub 3}, MgGeO{sub 3}, and CaIrO{sub 3}), and different results were obtained. To clarify this controversy, we report on transformation and deformation textures in MgGeO{sub 3} post-perovskite synthesized and deformed at room temperature in the diamond anvil cell. Transformed from the enstatite phase, MgGeO{sub 3} post-perovskite exhibits a transformation texture characterized by (100) planes at high angles to the direction of compression. Upon subsequent deformation, this texture changes and (001) lattice planes become oriented nearly perpendicular to compression, consistent with dominant (001)[100] slip. When MgGeO{sub 3} post-perovskite is synthesized from the perovskite phase, a different transformation texture is observed. This texture has (001) planes at high angle to compression and becomes slightly stronger upon compression. We also find that the yield strength of MgGeO{sub 3} post-perovskite is dependent on grain size and texture. Finer-grained samples exhibit higher yield strength and are harder to induce plastic deformation. Strong textures also affect the yield strength and can result in higher differential stresses. The inferred dominant (001) slip for pPv is significant for geophysics, because, when applied to geodynamic convection models, it predicts the observed anisotropies of S-waves as well as an anti-correlation between P- and S-waves.
M. A. Tschopp; J. L. Bouvard; D. K. Ward; D. J. Bammann; M. F. Horstemeyer
2013-10-02
Molecular dynamics simulations are increasingly being used to investigate the structural evolution of polymers during mechanical deformation, but relatively few studies focus on the influence of boundary conditions on this evolution, in particular the dissipation of both heat and pressure through the periodic boundaries during deformation. The research herein explores how the tensile deformation of amorphous polyethylene, modelled with a united atom method potential, is influenced by heat and pressure dissipation. The stress-strain curves for the pressure dissipation cases (uniaxial tension) are in qualitative agreement with experiments and show that heat dissipation has a large effect on the strain hardening modulus calculated by molecular dynamics simulations. The evolution of the energy associated with bonded and non-bonded terms was quantified as a function of strain as well as the evolution of stress in both the loading and non-loading directions to give insight into how the stress state is altered within the elastic, yield, strain softening, and strain hardening regions. The stress partitioning shows a competition between `tensile' Van der Waal's interactions and `compressive' bond stretching forces, with the characteristic yield stress peak clearly associated with the non-bonded stress. The lack of heat dissipation had the largest effect on the strain hardening regime, where an increase in the calculated temperature correlated with faster chain alignment in the loading direction and more rapid conformation changes. In part, these observations demonstrate the role that heat and pressure dissipation play on deformation characteristics of amorphous polymers, particularly for the strain hardening regime.
Kinematic quantities of finite elastic and plastic deformation
T. Fülöp; P. Ván
2012-03-05
Kinematic quantities for finite elastic and plastic deformations are defined via an approach that does not rely on auxiliary elements like reference frame and reference configuration, and that gives account of the inertial-noninertial aspects explicitly. These features are achieved by working on Galilean spacetime directly. The quantity expressing elastic deformations is introduced according to its expected role: to measure how different the current metric is from the relaxed/stressless metric. Further, the plastic kinematic quantity is the change rate of the stressless metric. The properties of both are analyzed, and their relationship to frequently used elastic and plastic kinematic quantities is discussed. One important result is that no objective elastic or plastic quantities can be defined from deformation gradient.
Angularly Deformed Special Relativity and its Results for Quantum Mechanics
Glinka, Lukasz Andrzej
2015-01-01
In this paper, the deformed Special Relativity, which leads to an essentially new theoretical context of quantum mechanics, is presented. The formulation of the theory arises from a straightforward analogy with the Special Relativity, but its foundations are laid through the hypothesis on breakdown of the velocity-momentum parallelism which affects onto the Einstein equivalence principle between mass and energy of a relativistic particle. Furthermore, the derivation is based on the technique of an eikonal equation whose well-confirmed physical role lays the foundations of both optics and quantum mechanics. As a result, we receive the angular deformation of Special Relativity which clearly depicts the new deformation-based theoretical foundations of physics, and, moreover, offers both constructive and consistent phenomenological discussion of the theoretical issues such like imaginary mass and formal superluminal motion predicted in Special Relativity for this case. In the context of the relativistic theory, p...
An application of the WKB method in deformation quantisation
Jaromir Tosiek; Ruben Cordero; Francisco J. Turrubiates
2015-02-19
An adaptation of the WKB method in the deformation quantisation formalism is presented with the aim to obtain an approximate technique of solving the eigenvalue problem for energy in the phase space quantum approach. A relationship between the phase $\\sigma(\\vec{r})$ of a wave function $\\exp \\left(\\frac{i}{\\hbar} \\sigma(\\vec{r}) \\right)$ and its respective Wigner function is derived. Formulas for a Wigner function of a wave function being a product of functions and a superposition of functions are proposed. Properties of a Wigner function of interfering states are investigated. An example of the semiclassical approximation in deformation quantisation is analysed.
Gotika, Priyanka
2012-02-14
: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 73 ix LIST OF FIGURES FIGURE Page 1 Constitutive relation for Bingham-type uid. Force due to dash- pot cannot be written as a function of kinematic variables (that is, velocity of the mass). On the other hand, as shown in the gure, velocity... of constitutive relation between velocity and force due to dash-pot for a dash-pot governed by visco-elastic model. : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 9 5 A pictorial representation of constitutive relation between velocity...
Modeling and Algorithmic Approaches to Constitutively-Complex, Microstructured Fluids
Miller, Gregory H.; Forest, Gregory
2011-12-22
We present a new multiscale model for complex uids based on three scales: microscopic, kinetic, and continuum. We choose the microscopic level as Kramers' bead-rod model for polymers, which we describe as a system of stochastic di#11;erential equations with an implicit constraint formulation. The associated Fokker-Planck equation is then derived, and adiabatic elimination removes the fast momentum coordinates. Approached in this way, the kinetic level reduces to a dispersive drift equation. The continuum level is modeled with a #12;nite volume Godunov-projection algorithm. We demonstrate computation of viscoelastic stress divergence using this multiscale approach.
Continuum-kinetic-microscopic model of lung clearance due to core-annular fluid entrainment
Mitran, Sorin
2013-07-01
The human lung is protected against aspirated infectious and toxic agents by a thin liquid layer lining the interior of the airways. This airway surface liquid is a bilayer composed of a viscoelastic mucus layer supported by a fluid film known as the periciliary liquid. The viscoelastic behavior of the mucus layer is principally due to long-chain polymers known as mucins. The airway surface liquid is cleared from the lung by ciliary transport, surface tension gradients, and airflow shear forces. This work presents a multiscale model of the effect of airflow shear forces, as exerted by tidal breathing and cough, upon clearance. The composition of the mucus layer is complex and variable in time. To avoid the restrictions imposed by adopting a viscoelastic flow model of limited validity, a multiscale computational model is introduced in which the continuum-level properties of the airway surface liquid are determined by microscopic simulation of long-chain polymers. A bridge between microscopic and continuum levels is constructed through a kinetic-level probability density function describing polymer chain configurations. The overall multiscale framework is especially suited to biological problems due to the flexibility afforded in specifying microscopic constituents, and examining the effects of various constituents upon overall mucus transport at the continuum scale.
Discrete micromechanics of elastoplastic crystals in the finite deformation range
Borja, Ronaldo I.
Available online 19 March 2014 Abstract We present a rate-independent crystal plasticity theory follows a well-established `ultimate algorithm' for rate-independent crystal plasticity developed for infinites- imal deformation. Ó 2014 Elsevier B.V. All rights reserved. Keywords: Crystal plasticity; Finite
Inhomogeneous deformation of a cone of Neo-Hookean material
Hariharakumar, Pradeep
2001-01-01
In this work we investigate, the nonlinear, elastic deformation of a cone made of a Neo-Hookean material. We use a semi-inverse method and assume a specific form of the displacement and the corresponding structure of the pressure field inside...
Analysis of deformation induced martensitic transformation in stainless steels
Cambridge, University of
Analysis of deformation induced martensitic transformation in stainless steels A. Das1,2,3 , P. C that the crystallographic texture due to martensitic transformation can be predicted for 18/8 austenitic stainless steel steel was prestrained and then tested in tension at a temperature where martensite was induced
Cross Section of Coils & Shielding Vessels; Stresses & Deformations Preliminary Results
McDonald, Kirk
Cross Section of Coils & Shielding Vessels; Stresses & Deformations Preliminary Results Bob Weggel 7/5--7/26/2011 The inner radius of the bore tube of the inner shielding vessel (longitudinal axis compressed) of inner and outer shielding vessels of design "Shields50mm.mph", including
Mechanical deformations of boron nitride nanotubes in crossed junctions
Zhao, Yadong; Chen, Xiaoming; Ke, Changhong; Park, Cheol; Fay, Catharine C.; Stupkiewicz, Stanislaw
2014-04-28
We present a study of the mechanical deformations of boron nitride nanotubes (BNNTs) in crossed junctions. The structure and deformation of the crossed tubes in the junction are characterized by using atomic force microscopy. Our results show that the total tube heights are reduced by 20%–33% at the crossed junctions formed by double-walled BNNTs with outer diameters in the range of 2.21–4.67?nm. The measured tube height reduction is found to be in a nearly linear relationship with the summation of the outer diameters of the two tubes forming the junction. The contact force between the two tubes in the junction is estimated based on contact mechanics theories and found to be within the range of 4.2–7.6 nN. The Young's modulus of BNNTs and their binding strengths with the substrate are quantified, based on the deformation profile of the upper tube in the junction, and are found to be 1.07?±?0.11 TPa and 0.18–0.29 nJ/m, respectively. Finally, we perform finite element simulations on the mechanical deformations of the crossed BNNT junctions. The numerical simulation results are consistent with both the experimental measurements and the analytical analysis. The results reported in this paper contribute to a better understanding of the structural and mechanical properties of BNNTs and to the pursuit of their applications.
Large Deformation Constitutive Laws for Isotropic Thermoelastic Materials
Plohr, Bradley J. [Los Alamos National Laboratory; Plohr, Jeeyeon N. [Los Alamos National Laboratory
2012-07-25
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
Optical switch using a deformable liquid droplet Hongwen Ren1,
Wu, Shin-Tson
. As the voltage increases, the dielectric force reshapes the droplet by uplifting its dome. As the dome touches developed a di- electric liquid droplet whose dome can be deformed from a spherical shape to flat, the dielectric force uplifts the dro- plet. As soon as the dome touches the top substrate, a clear channel
Deformation of the cell nucleus under indentation: Mechanics and mechanisms
Vaziri, Ashkan
-induced nuclear deformation and mechanisms of stress transition throughout the nucleus. Here, we develop representing the nucleoplasm and the nuclear envelope. The nuclear envelope itself is composed of three separate layers: two thin elastic layers representing the inner and outer nuclear membranes and one thicker
CONTAINED PLASTIC DEFORMATION NEAR CRACKS AND NOTCHES UNDER LONGITUDINAL SHEAR
CONTAINED PLASTIC DEFORMATION NEAR CRACKS AND NOTCHES UNDER LONGITUDINAL SHEAR James R. Rice* ABSTRACT An exact linear elastic-perfectly plastic solution is presented for the problem of a sharp notch coordinates corresponding to given stresses, position of the elastic-plastic boundary, and accompanying
Giant Monopole Resonance in Transitional and Deformed-Nuclei
Garg, U.; Bogucki, P.; Bronson, J. D.; Lui, YW; Youngblood, David H.
1984-01-01
reported in the actinide nuclei. The splitting of the GMR has been explained as resulting from the mixing of L =0 and I. =2 oscillations with the onset of deformation which results in a sharing of strength between the GMR and the IC =0 component...
Rock dilation, nonlinear deformation, and pore pressure change under shear
Lyakhovsky, Vladimir
Rock dilation, nonlinear deformation, and pore pressure change under shear Yariv Hamiel a criterion and pore pressure response to a fault slip. We investigate the poroelastic response of two an increase of pore pressure with mean stress (according to Skempton coefficient B) under undrained conditions
Coupling of Fluid Flow and Deformation in Underground Formations
This paper demonstrates the necessity of using the coupled Biot's equations for deformation-flow problems in ..... For most soils Ks is much larger than the bulk modulus K of .... Due to the stiffness and bending of the overburden, the reservoir.
Failing softly: A fracture theory of highly-deformable materials
Tamar Goldman Boué; Roi Harpaz; Jay Fineberg; Eran Bouchbinder
2015-03-24
Highly-deformable materials, from synthetic hydrogels to biological tissues, are becoming increasingly important from both fundamental and practical perspectives. Their mechanical behaviors, in particular the dynamics of crack propagation during failure, are not yet fully understood. Here we propose a theoretical framework for the dynamic fracture of highly-deformable materials, in which the effects of a dynamic crack are treated with respect to the nonlinearly deformed (pre-stressed/strained), non-cracked, state of the material. Within this framework, we derive analytic and semi-analytic solutions for the near-tip deformation fields and energy release rates of dynamic cracks propagating in incompressible neo-Hookean solids under biaxial and uniaxial loading. We show that moderately large pre-stressing has a marked effect on the stress fields surrounding a crack's tip. We verify these predictions by performing extensive experiments on the fracture of soft brittle elastomers over a range of loading levels and propagation velocities, showing that the newly developed framework offers significantly better approximations to the measurements than standard approaches at moderately large levels of external loadings and high propagation velocities. This framework should be relevant to the failure analysis of soft and tough, yet brittle, materials.
Characterization of Contour Shapes Achievable with a MEMS Deformable Mirror
Bifano, Thomas
Characterization of Contour Shapes Achievable with a MEMS Deformable Mirror Yaopeng Zhou and Thomas for a particular AO application can be determined. In this paper, we characterize one MEMS DM that was recently electrostatic actuation in an architecture that has been described previously. We incorporated the MEMS mirror
Automated Finite Element Analysis for Deformable Registration of Prostate Images
1 Automated Finite Element Analysis for Deformable Registration of Prostate Images Jessica R, Marco Zaider Abstract-- Two major factors preventing the routine clinical use of finite element analysis the effort required to apply finite element analysis to image registration. Encouraging results are presented
Deformation Behavior of Multilayer Aluminum Oxide/Molybdenum Composite
Collins, Gary S.
on the silicon wafer. The formula calculates the fracture toughness (Kc) of bulk brittle materials by measuring2O3 should be able to be made tougher by the addition of a more ductile material. In this experiment, molybdenum (Mo) was chosen as this ductile material. The deformation behavior of the multilayer coating
Projectile deformation effects in the breakup of $^{37}$Mg
Shubhchintak,; Shyam, R
2015-01-01
We study the breakup of $^{37}$Mg on Pb at 244MeV/u with the recently developed extended theory of Coulomb breakup within the post-form finite range distorted wave Born approximation that includes deformation of the projectile. Comparing our calculated cross section with the available Coulomb breakup data we determine the possible ground state configuration of $^{37}$Mg.
Path Deformation Roadmaps Leonard Jaillet and Thierry Simeon
Cortés, Juan
Path Deformation Roadmaps L´eonard Jaillet and Thierry Sim´eon LAAS-CNRS, Toulouse, France with PRM methods. Our aim is to compute good quality roadmaps that encode the multiple connectedness-PRM technique [12] to constructing compact roadmaps that encode a richer and more suitable information than
The Rate of Creep Deformation St Edmund's College, Cambridge
Cambridge, University of
and test the significant creep constitutive strain equations, 2.25Cr-1Mo steel has been selectedThe Rate of Creep Deformation By Yi Shen St Edmund's College, Cambridge University of Cambridge my parents Liping Wei and Derong Shen. #12;v Abstract Creep and creep fracture represent one
Fractal distribution function and fractal-deformed Heisenberg algebras
Wellington da Cruz
2002-10-01
We consider the concept of fractons, i.e. particles or quasiparticles which obey specific fractal distribution function and for each universal class h of particles we obtain a fractal-deformed Heisenberg algebra. This one takes into account the braid group structure of these objects which live in two-dimensional multiply connected space.
Structural control of elastic moduli in ferrogels and the importance of non-affine deformations
Giorgio Pessot; Peet Cremer; Dmitry Y. Borin; Stefan Odenbach; Hartmut Löwen; Andreas M. Menzel
2014-10-21
One of the central appealing properties of magnetic gels and elastomers is that their elastic moduli can reversibly be adjusted from outside by applying magnetic fields. The impact of the internal magnetic particle distribution on this effect has been outlined and analyzed theoretically. In most cases, however, affine sample deformations are studied and often regular particle arrangements are considered. Here we challenge these two major simplifications by a systematic approach using a minimal dipole-spring model. Starting from different regular lattices, we take into account increasingly randomized structures, until we finally investigate an irregular texture taken from a real experimental sample. On the one hand, we find that the elastic tunability qualitatively depends on the structural properties, here in two spatial dimensions. On the other hand, we demonstrate that the assumption of affine deformations leads to increasingly erroneous results the more realistic the particle distribution becomes. Understanding the consequences of the assumptions made in the modeling process is important on our way to support an improved design of these fascinating materials.
Hoo Fatt, Michelle S.
A theoretical approach was developed for predicting the plastic deformation of a cylindrical shell subject to asymmetric dynamic loads. The plastic deformation of the leading generator of the shell is found by solving for ...
ASYMPTOTIC AND COMPUTATIONAL ANALYSIS OF LARGE SHEAR DEFORMATIONS OF A THERMOPLASTIC MATERIAL
Edwards, David A.
ASYMPTOTIC AND COMPUTATIONAL ANALYSIS OF LARGE SHEAR DEFORMATIONS OF A THERMOPLASTIC MATERIAL D. A, asymptotics, finite differences, shear bands, singular perturbations, thermoplastic materials AMS subject of high strain that develop in materials under intense thermoplastic shear deformations. Since they often
Fossen, Haakon
Factors controlling permeability of cataclastic deformation bands and faults in porous sandstone March 2015 Available online 18 April 2015 Keywords: Cataclastic band Permeability Porous sandstone Fluid and their petrophysical properties is essential for realistic characterization of deformed sandstone reservoirs
Normal and lateral Casimir forces between deformed plates
Emig, Thorsten; Hanke, Andreas; Golestanian, Ramin; Kardar, Mehran [Institut fuer Theoretische Physik, Universitaet zu Koeln, Zuelpicher Strasse 77, D-50937 Cologne (Germany); Institut fuer Theoretische Physik, Universitaet Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart (Germany); Institute for Advanced Studies in Basic Sciences, Zanjan 45195-159 (Iran, Islamic Republic of); Institute for Studies in Theoretical Physics and Mathematics, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Physics Department, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2003-02-01
The Casimir force between macroscopic bodies depends strongly on their shape and orientation. To study this geometry dependence in the case of two deformed metal plates, we use a path-integral quantization of the electromagnetic field which properly treats the many-body nature of the interaction, going beyond the commonly used pairwise summation (PWS) of van der Waals forces. For arbitrary deformations we provide an analytical result for the deformation induced change in the Casimir energy, which is exact to second order in the deformation amplitude. For the specific case of sinusoidally corrugated plates, we calculate both the normal and the lateral Casimir forces. The deformation induced change in the Casimir interaction of a flat and a corrugated plate shows an interesting crossover as a function of the ratio of the mean plate distance H to the corrugation length {lambda}: For {lambda}<
Deformed diffusion and generalized Laplacian for directed networks
Michaël Fanuel; Johan A. K. Suykens
2015-11-02
A diffusion equation on a complex network is usually implemented with the help of the combinatorial Laplacian which incorporates information about the network structure. In this paper, a deformed diffusion equation on directed networks, governed by a generalized Laplacian, is introduced within a framework of discrete differential forms, closely related to combinatorial Hodge theory. Edge directions are incorporated with the help of an edge flow $1$-form, whose deforming impact is controlled by a coupling constant. Hence, information about the community structure is encoded in the dominant modes in the long time limit. On the one hand, for a small deformation of the combinatorial Laplacian, the dominant modes of the deformed diffusion allow to uncover community structures which are only encoded in the edge directions. We show that the dynamics distinguishes two categories of nodes, i.e. the nodes with a majority of outgoing links from the nodes with a majority of incoming links. Furthermore, the categorization naturally implements the connectivity of nodes and hence, goes beyond a simple degree counting. On the other hand, in the case of maximal deformation, the dominant modes of the dynamics characterize important nodes of the directed network that we name Bi-directional Outer Cores (BOC's) and Bi-directional Inner Cores (BIC's) which are the analogue of connected components of undirected networks. These BIC's and BOC's are shown to support stationary distributions. The relevance of these aspects is illustrated on a series of artificial and real-life directed networks such as a food web and a neuronal network.
Measuring skewness of red blood cell deformability distribution by laser ektacytometry
Nikitin, S Yu; Priezzhev, A V; Lugovtsov, A E; Ustinov, V D
2014-08-31
An algorithm is proposed for measuring the parameters of red blood cell deformability distribution based on laser diffractometry of red blood cells in shear flow (ektacytometry). The algorithm is tested on specially prepared samples of rat blood. In these experiments we succeeded in measuring the mean deformability, deformability variance and skewness of red blood cell deformability distribution with errors of 10%, 15% and 35%, respectively. (laser biophotonics)
Eberhardt, Erik
Internal structure and deformation of an unstable crystalline rock mass above Randa (Switzerland of Technology, ETH Hoenggerberg, ZÃ¼rich, Switzerland b Institute of Geophysics, Swiss Federal Institute of Technology, ETH Hoenggerberg, ZÃ¼rich, Switzerland a b s t r a c ta r t i c l e i n f o Article history
Moody, Neville Reid; Bahr, David F.
2005-11-01
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.
Deformations of polyhedra and polygons by the unitary group
Livine, Etera R.
2013-12-15
We introduce the set of framed (convex) polyhedra with N faces as the symplectic quotient C{sup 2N}//SU(2). A framed polyhedron is then parametrized by N spinors living in C{sup 2} satisfying suitable closure constraints and defines a usual convex polyhedron plus extra U(1) phases attached to each face. We show that there is a natural action of the unitary group U(N) on this phase space, which changes the shape of faces and allows to map any (framed) polyhedron onto any other with the same total (boundary) area. This identifies the space of framed polyhedra to the Grassmannian space U(N)/ (SU(2)×U(N?2)). We show how to write averages of geometrical observables (polynomials in the faces' area and the angles between them) over the ensemble of polyhedra (distributed uniformly with respect to the Haar measure on U(N)) as polynomial integrals over the unitary group and we provide a few methods to compute these integrals systematically. We also use the Itzykson-Zuber formula from matrix models as the generating function for these averages and correlations. In the quantum case, a canonical quantization of the framed polyhedron phase space leads to the Hilbert space of SU(2) intertwiners (or, in other words, SU(2)-invariant states in tensor products of irreducible representations). The total boundary area as well as the individual face areas are quantized as half-integers (spins), and the Hilbert spaces for fixed total area form irreducible representations of U(N). We define semi-classical coherent intertwiner states peaked on classical framed polyhedra and transforming consistently under U(N) transformations. And we show how the U(N) character formula for unitary transformations is to be considered as an extension of the Itzykson-Zuber to the quantum level and generates the traces of all polynomial observables over the Hilbert space of intertwiners. We finally apply the same formalism to two dimensions and show that classical (convex) polygons can be described in a similar fashion trading the unitary group for the orthogonal group. We conclude with a discussion of the possible (deformation) dynamics that one can define on the space of polygons or polyhedra. This work is a priori useful in the context of discrete geometry but it should hopefully also be relevant to (loop) quantum gravity in 2+1 and 3+1 dimensions when the quantum geometry is defined in terms of gluing of (quantized) polygons and polyhedra.
ORIGINAL PAPER The legacy of crystal-plastic deformation in olivine
Jung, Haemyeong
ORIGINAL PAPER The legacy of crystal-plastic deformation in olivine: high-diffusivity pathways Abstract Crystal-plastic olivine deformation to produce subgrain boundaries composed of edge dislocations is an inevitable consequence of asthenospheric mantle flow. Although crystal-plastic deformation
Adiabatic shear banding in ultrafine-grained Fe processed by severe plastic deformation
Wei, Qiuming
. Keywords: Shear bands; Severe plastic deformation; Ultrafine microstructure; Mechanical properties; DynamicAdiabatic shear banding in ultrafine-grained Fe processed by severe plastic deformation Q. Wei a December 2003; accepted 17 December 2003 Abstract We have investigated the plastic deformation behavior
Oil and Gas CDT Bots in Rocks: Intelligent Rock Deformation for Fault Rock
Henderson, Gideon
Heriot-Watt University, Institute of Petroleum Engineering Supervisory Team · Dr Helen Lewis, Heriot://www.pet.hw.ac.uk/staff-directory/jimsomerville.htm Key Words Nano/Micro sensors; faults; fault zones; geomechanics; rock mechanics; rock deformation-deformed equivalent, a different lab-deformed example and a geomechanical simulation of a fault zone showing permanent
Plastic Deformation of Single Nanometer-Sized Crystals Litao Sun,1,2
Nordlund, Kai
Plastic Deformation of Single Nanometer-Sized Crystals Litao Sun,1,2 Arkady V. Krasheninnikov,3 observations of the plastic deformation of individual nanometer- sized Au, Pt, W, and Mo crystals. Specifically. The correlation with atomistic simulations shows that the observed slow plastic deformation is due to dislocation
PLASTIC VERSUS ELASTIC DEFORMATION EFFECTS ON MAGNETIC BARKHAUSEN NOISE IN STEEL
Clapham, Lynann
PLASTIC VERSUS ELASTIC DEFORMATION EFFECTS ON MAGNETIC BARKHAUSEN NOISE IN STEEL C.-G. STEFANITA, D) AbstractÐA study was performed to dierentiate the eects of elastic and plastic deformation on magnetic samples subjected to varying degrees of uniaxial elastic and plastic deformation up to H40% strain
MEMS Deformable Mirrors for Astronomical Adaptive Optics S.A. Cornelissen1
Bifano, Thomas
on the development of high actuator count, micro-electromechanical (MEMS) deformable mirrors designed for high order Microelectromechanical systems (MEMS) based deformable mirrors (DMs) are an emerging class of wavefront correctors usedMEMS Deformable Mirrors for Astronomical Adaptive Optics S.A. Cornelissen1 , A.L. Hartzell1 , J
Mining-related ground deformation in Crescent Valley, Nevada: Implications for sparse GPS networks
Amelung, Falk
Mining-related ground deformation in Crescent Valley, Nevada: Implications for sparse GPS networks. The analysis reveals areas of rapid deformation caused by mining and agricultural activities in the Crescent), Mining-related ground deformation in Crescent Valley, Nevada: Implications for sparse GPS networks
Development of a 4096 Element MEMS Continuous Membrane Deformable Mirror for High Contrast
Bifano, Thomas
Development of a 4096 Element MEMS Continuous Membrane Deformable Mirror for High Contrast star. This surface micromachined MEMS deformable mirror will have an active aperture of 25.2mm developed for commercially available 1024 and 140 element MEMS deformable mirrors to achieve unprecedented
MEMS Deformable Mirror Actuators with Enhanced Reliability S.A. Cornelissena
Bifano, Thomas
MEMS Deformable Mirror Actuators with Enhanced Reliability S.A. Cornelissena , T.G. Bifanoa,b , P, 15 St. Mary's St., Boston, MA 02215 ABSTRACT MEMS deformable mirrors with thousands of actuators due to electrical overstress. We report on advances made in the development of MEMS deformable mirror
Ultrafine-grain-sized zirconium by dynamic deformation , J.-M. Gebert b
Meyers, Marc A.
Ultrafine-grain-sized zirconium by dynamic deformation B.K. Kad a , J.-M. Gebert b , M.T. Perez A polycrystalline zirconium alloy (Zircadine 702, containing 0.7% Hf) was subjected to high plastic strains (shear deformation; Zirconium; Dynamic deformation 1. Introduction Polycrystalline metals with grain sizes