scholarly journals Regulating surface wrinkles using light

2020 ◽  
Vol 7 (7) ◽  
pp. 1247-1257
Author(s):  
Liangwei Zhou ◽  
Kaiming Hu ◽  
Wenming Zhang ◽  
Guang Meng ◽  
Jie Yin ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Boundary Conditions ◽  
Functional Materials ◽  
Two Dimensions ◽  
Stress Distributions ◽  
Fabrication Technology ◽  
On Demand ◽  
Optical Grating ◽  
Wrinkle Structures ◽  
Basic Characteristics

Abstract Regulating existing micro and nano wrinkle structures into desired configurations is urgently necessary yet remains challenging, especially modulating wrinkle direction and location on demand. In this work, we propose a novel light-controlled strategy for surface wrinkles, which can dynamically and precisely regulate all basic characteristics of wrinkles, including wavelength, amplitude, direction and location (λ, A, θ and Lc), and arbitrarily tune wrinkle topographies in two dimensions (2D). By considering the bidirectional Poisson's effect and soft boundary conditions, a modified theoretical model depicting the relation between stress distributions and the basic characteristics was developed to reveal the mechanical mechanism of the regulation strategy. Furthermore, the resulting 2D ordered wrinkles can be used as a dynamic optical grating and a smart template to reversibly regulate the morphology of various functional materials. This study will pave the way for wrinkle regulation and guide fabrication technology for functional wrinkled surfaces.

Transition Times in Memory

2018 ◽  
Author(s):  
Donatella della Porta ◽  
Massimiliano Andretta ◽  
Tiago Fernandes ◽  
Eduardo Romanos ◽  
Markos Vogiatzoglou
Keyword(s):  
Theoretical Model ◽  
Social Movement ◽  
Transition Period ◽  
Two Dimensions ◽  
Democratic Regime ◽  
Organizational Models ◽  
Different Types ◽  
Transition Times ◽  
Movement Participation

The second chapter covers the main characteristics of transition time in the four countries: Italy, Greece, Spain, and Portugal. After developing the theoretical model on paths of transition, with a focus on social movement participation, the chapter looks at social movements and protest events as turning points during transition, covering in particular the specific movement actors, their organizational models, and their repertoires of action and frames. The chapter focuses on two dimensions: the role of mobilization in the transition period, which implies the analysis of how elites and masses interact, ally, or fight with each other in the process, and the outcome of transitions as continuity versus rupture of the democratic regime vis-à-vis the old one. It concludes by elaborating some hypotheses on how different modes of transition may produce different types and uses of (transition) memories.

scholarly journals Boundary states for chiral symmetries in two dimensions

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Philip Boyle Smith ◽  
David Tong
Keyword(s):  
Boundary Conditions ◽  
Ground State ◽  
Zero Mode ◽  
Central Charge ◽  
Two Dimensions ◽  
Dirac Fermions ◽  
Chiral Symmetries ◽  
Boundary States ◽  
Ground State Degeneracy ◽  
Left And Right

Abstract We study boundary states for Dirac fermions in d = 1 + 1 dimensions that preserve Abelian chiral symmetries, meaning that the left- and right-moving fermions carry different charges. We derive simple expressions, in terms of the fermion charge assignments, for the boundary central charge and for the ground state degeneracy of the system when two different boundary conditions are imposed at either end of an interval. We show that all such boundary states fall into one of two classes, related to SPT phases supported by (−1)F , which are characterised by the existence of an unpaired Majorana zero mode.

Dynamic simulation of the motion of capsules in pipelines

1995 ◽  
Vol 286 ◽  
pp. 201-227 ◽  
Author(s):  
J. Feng ◽  
P. Y. Huang ◽  
D. D. Joseph
Keyword(s):  
Lift Force ◽  
Two Dimensions ◽  
Inertial Forces ◽  
Stress Distributions ◽  
Three Stages ◽  
Heavy Crude ◽  
Lift Off ◽  
Experimental Values ◽  
Transient Oscillations ◽  
Core Flows

In this paper we report results of two-dimensional simulations of the motion of elliptic capsules carried by a Poiseuille flow in a channel. The numerical method allows computation of the capsule motion and the fluid flow around the capsule, and accurate evaluation of the lift force and torque. Results show that the motion of a capsule which is heavier than the carrying fluid may be decomposed into three stages: initial lift-off, transient oscillations and steady flying. The behaviour of the capsule during initial lift-off and steady flying is analysed by studying the pressure and shear stress distributions on the capsule. The dominant mechanism for the lift force and torque is lubrication or inertia or a combination of the two under different conditions. The lift-off velocity for the ellipse in two dimensions is compared with experimental values for cylindrical capsules in pipes. Finally, the mechanisms of lift for capsules are applied to flying core flows, and it is argued that inertial forces are responsible for levitating heavy crude oil cores lubricated by water in a horizontal pipeline.

Stress Distributions in an Elastic Body due to Molecular Interactions Considering One-Dimensional Periodic Material Distribution Based on Mindlin Solution

2018 ◽  
Author(s):  
Hiroshige Matsuoka ◽  
Toshiki Otani ◽  
Shigehisa Fukui
Keyword(s):  
Stress Distribution ◽  
Elastic Body ◽  
Molecular Interactions ◽  
Material Distribution ◽  
Stress Distributions ◽  
One Dimensional ◽  
Calculation Results ◽  
Basic Characteristics ◽  
The One

A method to calculate the stress distributions in the elastic body caused by the molecular interactions has been established. The stress distribution was calculated based on the Mindlin’s solution considering the one-dimensional periodic material distribution. The calculation results for a distribution of two materials were presented. The basic characteristics of the stress distribution in the elastic body were quantitatively clarified.

scholarly journals Functional Materials Produced On An Industrial Scale

2015 ◽  
Vol 36 (1) ◽  
pp. 19-30
Author(s):  
Justyna Barska ◽  
Sylwester Kłysz
Keyword(s):  
Smart Materials ◽  
Industrial Production ◽  
Functional Materials ◽  
Industrial Scale ◽  
Wide Range ◽  
Basic Characteristics

AbstractThe article presents a wide range of applications of functional materials and a scale of their current industrial production. These are the materials which have specific characteristics, thanks to which they became virtually indispensable in certain constructional solutions. Their basic characteristics, properties, methods of production and use as smart materials were described.

Linear Static, Real-Time Finite Element Computations Based on Element Masks

2011 ◽  
Author(s):  
Holger Graf ◽  
Andre´ Stork
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Boundary Conditions ◽  
Real Time ◽  
Stiffness Matrix ◽  
New Method ◽  
Stress Distributions ◽  
Post Processing ◽  
Time Performance ◽  
Computational Overhead

This paper presents a new method for the manipulation of a given CAE domain in view of VR based explorations that enables engineers to interactively inspect and analyze a linear static domain. The interactions can ideally be performed in real-time in order to provide an intuitive impression of the changes to the underlying volumetric domain. We take the approach of element masking, i.e. the blending out of computations resulting from computational overhead for inner nodes, based on the inversion of the stiffness matrix. This allows us to optimize the re-simulation loop and to achieve real-time performance for strain and stress distributions with immediate visualization feedback caused by interactively changing boundary conditions. The novelty of the presented approach is a direct coupling of view dependent simulations and its close linkage to post-processing tasks. This allows engineers to also inspect the changes of the stress field inside of the volume during, e.g. cross sectioning.

A phase-field-based lattice Boltzmann method for moving contact line problems on curved stationary boundaries in two dimensions

2019 ◽  
Vol 30 (06) ◽  
pp. 1950044
Author(s):  
Weifeng Zhao
Keyword(s):  
Boundary Conditions ◽  
Lattice Boltzmann Method ◽  
Contact Line ◽  
Phase Field ◽  
Lattice Boltzmann ◽  
Two Dimensions ◽  
Curved Boundaries ◽  
Moving Contact Line ◽  
Moving Contact ◽  
Boltzmann Method

In this work, we propose a phase-field-based lattice Boltzmann method to simulate moving contact line (MCL) problems on curved boundaries. The key point of this method is to implement the boundary conditions on curved solid boundaries. Specifically, we use our recently proposed single-node scheme for the no-slip boundary condition and a new scheme is constructed to deal with the wetting boundary conditions (WBCs). In particular, three kinds of WBCs are implemented: two wetting conditions derived from the wall free energy and a characteristic MCL model based on geometry considerations. The method is validated with several MCL problems and numerical results show that the proposed method has utility for all the three WBCs on both straight and curved boundaries.

Boundary conditions on a finite grid: Applications with pseudospectral wave propagation

Geophysics ◽  
1997 ◽  
Vol 62 (5) ◽  
pp. 1544-1557 ◽  
Author(s):  
Huatao Wu ◽  
Jonathan M. Lees
Keyword(s):  
Wave Propagation ◽  
Free Surface ◽  
Boundary Conditions ◽  
Optimal Parameter ◽  
Two Dimensions ◽  
New Method ◽  
Head Waves ◽  
Vertical Fault ◽  
Reduction Function ◽  
Grid Nodes

A new method for calculating boundary conditions at the free surface and along absorbing boundaries of a finite grid is presented. A finite, twice differentiable reduction function that achieves a 99% reduction over three wavelengths is proposed and tested. In the context of pseudospectral wave propagation, this implies a boundary layer of at least six grid nodes. The method is analyzed in one and two dimensions and the problems of waves impinging on corners are addressed. The reduction function recommended is [Formula: see text] where α is a parameter to be determined by optimization. Tests of the performance of the new method versus other common schemes are presented and analyzed. We provide a strategy for determining the optimal parameter in the reduction function. Synthetic Rayleigh waves are observed at the free surface of the simulation. Experiments with a vertical fault plane show the presence of direct, reflected, transmitted, and head waves. The presence of head waves may be used to analyze velocity contrasts across fault zones.

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