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This paper presents domain form of the interaction integrals based on three independent formulations for computation of the stress intensity factors and electric displacement intensity factor for cracks in functionally graded piezoelectric materials. Conservation integrals of J-type are derived based on the governing equations for piezoelectric media and the crack tip asymptotic fields of homogeneous piezoelectric medium as auxiliary fields. Each of the formulation differs in the way auxiliary fields are imposed in the evaluation of interaction integral and each of them results in a consistent form of the interaction integral in the sense that extra terms naturally appears in their derivation to compensate for the difference in the chosen crack tip asymptotic fields of homogeneous and functionally graded piezoelectric medium. The additional terms play an important role of ensuring domain independence of the presented interaction integrals. Comparison of the numerically evaluated intensity factors through the three consistent formulations with those obtained using displacement extrapolation method is presented by means of two examples. � 2008 Elsevier Ltd. All rights reserved.

Flow visualization studies on the effect of a splitter plate (SP) in the wake of rectangular cylinders of aspect ratios 0.1 and 1.0 are presented; the aspect ratio being defined as the ratio of the depth (B) of the cylinder to the width (D) of the cylinder. The length of the splitter plate is kept as 1D. The SP is placed parallel to the centerline, both along and away from it. The gap between the rear of the cylinder and the leading edge of SP is denoted by G and the lateral position from the centerline is denoted by Z. It is observed that for a model with the B/D ratio of 0.1, the SP has no significant influence on the flow when placed beyond G/D of 2.5 at Z/D of 0.0 While for the square cylinder case, the SP has no appreciable effect for G/D > 1.25D along the centerline at Z/D = 0.0. The critical gap defined as the G/D for which undulations in the flow pattern behind the cylinder are minimized, is found to be 2.25D and 1D respectively for rectangular and square cylinders when the SP is placed along the centerline. Influence of Z/D on the critical gap is also examined. The critical gap is observed to be always lower for the square cylinder. Copyright ? 2005 Begell House, Inc.

Date of Conference: 10-17 August 2005 Conference Name: 24th International Conference on Low Temperature Physics, LT24 2005 Motivated by the pionieering experiments of Buks et al. [Nature 391, 871 (1998)] we investigate the visibility of the Fano effect in a single-dot Aharonov-Bohm interferometer which is Coulomb-coupled to a nearby quantum dot. The latter acts as a 'Which Path Detector' and is coupled to two leads on which a finite bias is applied. Using the non-equilibrium Keldysh-Green function formalism we compute the currents through the detector and the interferometer. We take into account the first two contributions to the interaction selfenergy and emphasize the correction to the Landauer formula which appears beyond the single-particle approximation. Particular attention is given to the coherence properties of the interferometer in the presence of the electron-electron interaction between the embedded dot and the detector. We show that when the detector is subjected to a finite bias the amplitude of Aharonov-Bohm oscillations of the current through the interferometer decreases. The Fano line is in turn rather stable under interaction. Our results generalize an earlier work of Silva and Levit [Phys. Rev. B 63, 201309 (2001)] and complement the existing description of the controlled dephasing.

In this paper, we study the Dzyaloshinskii-Moriya (DM) anisotropic XX spin-chain model in the presence of an external homogeneous magnetic field. We found that the Berry phase of the system varies interestingly with small and large amounts of DM interaction and the magnetic field. In addition, we also considered the concurrence (i.e., the amount of entanglement) of the system, and the relationship between the concurrence and the Berry phase. Finally, we calculate the Berry phase of thermal states and verify that the results are consistent with that of the pure states., A*Star Grant No. 012-104-0040 and by the National Research Foundation & Ministry of Education, Singapore

In this paper, instability mechanisms in a low Mach number reacting flow are investigated. Here, the emphasis is on the growth or decay of acoustic oscillations which arise from the acoustic-hydrodynamic interaction in a low Mach number reacting flow. Motivated by the studies in magnetohydrodynamics and atmospheric flows, we propose to investigate the acoustic-hydrodynamic coupling as a system of wave-mean flow interaction. For example, a comparison with the heat fluctuation modified hydrodynamics associated with magnetohydrodynamics is useful in understanding this coupling. The wavelike acoustic disturbance is introduced here as a compressibility correction to the mean flow. Accounting for the multiple scales introduced by the weak compressibility, we derive a set of equations governing wave-mean flow interaction in a reacting low Mach number flow. Sources such as volume expansion (which, in atmospheric flows arises due to the density variation with altitude) occur in reacting flows due to the heat release rate. This heat release rate, when coupled with the acoustic field, often leads to self-sustained thermo-acoustic oscillations. In the study of such oscillations, we discover a relation between the acoustic pressure and second order thermal fluctuations. Further, using this relation, we discover the nonlinear coupling mechanism that would lead to self-sustained oscillations in a reacting low Mach number flow. This mechanism, represented by a coupled convection reaction diffusion system, is presented here for the first time. In addition to the acoustic pressure and temperature fields, we also discover the role of acoustic velocity field in the acoustic-hydrodynamic interaction through a convective and lift-up mechanism. � 2015 AIP Publishing LLC.

A detailed experimental investigation of interaction of free convection and radiation in a single fin mounted on a heated horizontal base has been carried out. The study makes use of a differential interferometer for estimating the convective heat fluxes. A numerical method coupled with the experimentally measured convective fluxes is used to evaluate the radiative fluxes. Experiments were conducted to study the effect of fin height, surface emissivity and the base temperature level on convection and radiation. Based on the experiments correlations have been presented for both the total and radiative heat transfer rates from the fin flats. Comparisons are made between the experimental results and two-dimensional numerical computations based on finite volume method. ? 1997 Elsevier Science Ltd.