On the role of boundary terms in the AdS/CFT correspondence

We consider a scalar field theory on AdS, and show that the usual AdS/CFT prescription is unable to map to the boundary a part of the information arising from the quantization in the bulk. We propose a solution to this problem by defining the energy of the theory in the bulk through the Noether current corresponding to time displacements, and, in addition, by introducing a proper generalized AdS/CFT prescription. We also show how this extended formulation could be used to consistently describe double-trace interactions in the boundary. The formalism is illustrated by focusing on the non-minimally coupled case using Dirichlet boundary conditions. © 2004 Published by Elsevier B.V.

A 2-D delaunay refinement algorithm using an initial prerefinement from the boundary mesh

An improvement to the quality bidimensional Delaunay mesh generation algorithm, which combines the mesh refinement algorithms strategy of Ruppert and Shewchuk is proposed in this research. The developed technique uses diametral lenses criterion, introduced by L. P. Chew, with the purpose of eliminating the extremely obtuse triangles in the boundary mesh. This method splits the boundary segment and obtains an initial prerefinement, and thus reducing the number of necessary iterations to generate a high quality sequential triangulation. Moreover, it decreases the intensity of the communication and synchronization between subdomains in parallel mesh refinement. © 2008 IEEE.

Small- and medium-sized enterprises' restructuring in a context of transition: a shared process: inter-player effects on efficient boundary choice in the Argentine manufacturing sector

Includes bibliography

Boundary of the rauzy fractal sets in ℝ×ℂgenerated by p(x) = x 4- x 3 - x 2 -x- 1

We study the boundary of the 3-dimensional Rauzy fractal ε ⊂ ℝ×ℂ generated by the polynomial P(x) Dx 4-x 3-x 2-x-1. The finite automaton characterizing the boundary of ε is given explicitly. As a consequence we prove that the set ε has 18 neighboors where 6 of them intersect the central tile ε in a point. Our construction shows that the boundary is generated by an iterated function system starting with 2 compact sets.

Simulation of the flow through automatic valves of hermetic compressors by the immersed boundary method approach

The main goal of the present work is to verify the applicability of the Immersed Boundary Method together with the Virtual Physical Model to solve the flow through automatic valves of hermetic compressors. The valve was simplified to a two-dimensional radial diffuser, with diameter ratio of D/d = 1.5, and simulated for a one cycle of opening and closing process with a imposed velocity of 3.0 cm/s for the reed, dimensionless gap between disks in the range of 0.07 < s/d < 0.10, and inlet Reynolds number equal to 1500. The good results obtained showed that the methodology has great potential as project tool for this type of valve systems. © The Authors, 2011.

An anisotropic linear elastic boundary element formulation for masonry wall analysis

This work presents an application of a Boundary Element Method (BEM) formulation for anisotropic body analysis using isotropic fundamental solution. The anisotropy is considered by expressing a residual elastic tensor as the difference of the anisotropic and isotropic elastic tensors. Internal variables and cell discretization of the domain are considered. Masonry is a composite material consisting of bricks (masonry units), mortar and the bond between them and it is necessary to take account of anisotropy in this type of structure. The paper presents the formulation, the elastic tensor of the anisotropic medium properties and the algebraic procedure. Two examples are shown to validate the formulation and good agreement was obtained when comparing analytical and numerical results. Two further examples in which masonry walls were simulated, are used to demonstrate that the presented formulation shows close agreement between BE numerical results and different Finite Element (FE) models. © 2012 Elsevier Ltd.

An exact series solution for the vibration analysis of cylindrical shells with arbitrary boundary conditions

In this paper, an exact series solution for the vibration analysis of circular cylindrical shells with arbitrary boundary conditions is obtained, using the elastic equations based on Flügge's theory. Each of the three displacements is represented by a Fourier series and auxiliary functions and sought in a strong form by letting the solution exactly satisfy both the governing differential equations and the boundary conditions on a point-wise basis. Since the series solution has to be truncated for numerical implementation, the term exactly satisfying should be understood as a satisfaction with arbitrary precision. One of the important advantages of this approach is that it can be universally applied to shells with a variety of different boundary conditions, without the need of making any corresponding modifications to the solution algorithms and implementation procedures as typically required in other techniques. Furthermore, the current method can be easily used to deal with more complicated boundary conditions such as point supports, partial supports, and non-uniform elastic restraints. Numerical examples are presented regarding the modal parameters of shells with various boundary conditions. The capacity and reliability of this solution method are demonstrated through these examples. © 2012 Elsevier Ltd. All rights reserved.

Morphotropic phase boundary and electrical properties of 1-x[Bi 0.5Na0.5]TiO3 -xBa[Zr0.25Ti 0.75]O3 lead-free piezoelectric ceramics

Lead-free solid solutions (1-x)Bi0.5Na0.5TiO 3 (BNT)-xBaZr0.25Ti0.75O3 (BZT) (x=0, 0.01, 0.03, 0.05, and 0.07) were prepared by the solid state reaction method. X-ray diffraction (XRD) and Rietveld refinement analyses of 1-x(BNT)-x(BZT) solid solution ceramic were employed to study the structure of these systems. A morphotropic phase boundary (MPB) between rhombohedral and cubic structures occured at the composition x=0.05. Raman spectroscopy exhibited a splitting of the (TO3) mode at x=0.05 and confirmed the presence of MPB region. Scanning electron microcopy (SEM) images showed a change in the grain shape with the increase of BZT into the BNT matrix lattice. The temperature dependent dielectric study showed a gradual increase in dielectric constant up to x=0.05 and then decrease with further increase in BZT content. Maximum coercive field, remanent polarization and high piezoelectric constant were observed at x=0.05. Both the structural and electrical properties show that the solid solution has an MPB around x=0.05. © 2012 Elsevier Ltd and Techna Group S.r.l.

Energy decay for the linear Klein-Gordon equation and boundary control

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

PROJECTIONS OF HYPERSURFACES IN R-4 WITH BOUNDARY TO PLANES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A BOUNDARY ELEMENT FORMULATION FOR MASONRY WALLS: NON-LINEAR ANALYSIS

In this work, a non-linear Boundary Element Method (BEM) formulation with damage model is extended for numerical simulation of structural masonry walls in 2D stress analysis. The formulation is reoriented to analyse structural masonry, the component materials of which, clay bricks and mortar, are considered as damaged materials. Also considered are the internal variables and cell discretization of the domain. A damage model is used to represent the material behaviour and the domain discretization is also proposed and discussed. The paper presents the numerical parameters of the damage model for the material properties of the masonry components, clay bricks and mortar. Some examples are shown to validate the formulation.

Physical properties of self-polarized PZT thin films at compositions around the morphotropic phase boundary

The physical properties of self-polarized PbZr1-xTixO3 thin films with no preferential orientation in a range of compositions 0.46 <= x <= 0.50 were investigated. Structural analysis revealed the coexistence of monoclinic-tetragonal and monoclinic-rhombohedral phases at compositions 0.46 <= x <= 0.49, where the monoclinic phase was in the majority and both the tetragonal and the rhombohedral phases in the minority. The dielectric permittivity (epsilon'= 447) reached its maximum at around composition x = 0.48. Asymmetries in the macroscopic and local hysteresis loops confirmed the existence of the self-polarization effect in the studied films.

New features of the morphotropic phase boundary in the PbZrO 3-PbTiO3 system: A Raman spectroscopy study

In this work we present a Raman study of PbZr1-xTi xO3 ceramics with composition values close to the morphotropic phase boundary region. The analysis of the Raman spectra leads to the determination of the monoclinic phase extension at different temperatures in a very good agreement with those determined by diffraction techniques. Therefore the obtained results show that Raman spectroscopy is a powerful and suitable technique to study structural phase transitions in PbZr 1-xTixO3. © 2002 Taylor & Francis.

A geometric approach to cosmological boundary conditions

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The paramagnetic phase boundary of EuTe at low temperatures

Taking into account the presence of long-range dipolar interactions, we propose a model hamiltonian to calculate the canted-paramagnetic phase boundary of EuTe at low temperatures. By using spin-wave techniques we show that the critical field depends on T2 asymptotically. Our calculations are in good agreement with the experimental data. © 1981.