Osorio Rivera Fray León¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.7, No.2, pp. 63-76, 2008, DOI:10.3970/icces.2008.007.063

Abstract In the development context of a project about a system of selection uchuva for export by means of artificial vision whose objective is to provide an electromechanical system to able to select uchuvas by searching on its physical appearance, some algorithms have been developed to extract the necessary details beginning with the image of the acquired fruit using a camera. As a result, it must be able to determine if the visualized uchuva presents some symptom (insects, fungus, and deterioration) that indicates if it should be discharged. More >

LiviuMarin ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.37, No.3, pp. 203-242, 2008, DOI:10.3970/cmes.2008.037.203

Abstract In this paper, a meshless method for the stable solution of direct and inverse problems associated with the two-dimensional Laplace equation in the presence of boundary singularities and noisy boundary data is proposed. The governing equation and boundary conditions are discretized by the method of fundamental solutions (MFS), whilst the existence of the boundary singularity is taken into account by subtracting from the original MFS solution the corresponding singular solutions, as given by the asymptotic expansion of the solution near the singular point. However, even in the case when the boundary singularity is accounted for, More >

De-hao Yu¹ ,Hong-ying Huang²

CMES-Computer Modeling in Engineering & Sciences, Vol.35, No.3, pp. 227-252, 2008, DOI:10.3970/cmes.2008.035.227

Abstract In this paper, we apply the artificial boundary method to solve a three-dimensional nonlinear interface problem on an unbounded domain. A spherical or ellipsoidal surface as the artificial boundary is introduced. The exact artificial boundary conditions are derived explicitly in terms of an infinite series and then the well-posedness of the coupled weak formulation in a bounded domain, which is equivalent to the original problem in the unbounded domain, is obtained. The error estimate depends on the mesh size, the term after truncating the infinite series and the location of the artificial boundary. Some numerical More >

C. Jeong¹, L.F. Kallivokas²

CMES-Computer Modeling in Engineering & Sciences, Vol.35, No.1, pp. 49-72, 2008, DOI:10.3970/cmes.2008.035.049

Abstract We discuss the inverse scattering problem of identifying the shape and location of a rigid scatterer fully buried in a homogeneous halfplane, when illuminated by surficial (line) wave sources generating SH waves. To this end, we consider the full-waveform response of the coupled host-obstacle system in the frequency domain, and employ the apparatus of partial-differential-equation-constrained optimization, augmented with total differentiation for tracking shape evolutions across inversion iterations, and specialized continuation schemes in lieu of formal regularization. We report numerical results that provide evidence of algorithmic robustness for detecting a variety of shapes, including elliptically- and More >

Liviu Marin¹

CMES-Computer Modeling in Engineering & Sciences, Vol.30, No.2, pp. 99-122, 2008, DOI:10.3970/cmes.2008.030.099

Abstract The application of the method of fundamental solutions (MFS) to inverse boundary value problems associated with the steady-state heat conduction in isotropic media in the presence of sources, i.e. the Poisson equation, is investigated in this paper. Based on the approach of Alves and Chen (2005), these problems are solved in two steps, namely by finding first an approximate particular solution of the Poisson equation and then the numerical solution of the resulting inverse boundary value problem for the Laplace equation. The resulting MFS discretised system of equations is ill-conditioned and hence it is solved More >

Tienfuan Kerh^1,2, J.S. Lai¹, D. Gunaratnam², R. Saunders²

CMES-Computer Modeling in Engineering & Sciences, Vol.26, No.1, pp. 1-12, 2008, DOI:10.3970/cmes.2008.026.001

Abstract Taiwan frequently suffers from strong ground motion, and the current building code is essentially based on two seismic zones, A and B. The design value of horizontal acceleration for zone A is 0.33g, and the value for zone B is 0.23g. To check the suitability of these values, a series of actual earthquake records are considered for evaluating peak ground acceleration (PGA) for each of the zones by using neural network models. The input parameters are magnitude, epicenter distance, and focal depth for each of the checking stations, and the peak ground acceleration is calculated… More >

L.K. Keppas¹, G.I. Giannopoulos¹, N.K. Anifantis¹

CMES-Computer Modeling in Engineering & Sciences, Vol.25, No.3, pp. 181-196, 2008, DOI:10.3970/cmes.2008.025.181

Abstract In the present paper a boundary element procedure is formulated to treat two-dimensional time dependent thermo-elastic contact problems incorporating thermal resistance along the contacting surfaces. The existence of pressure-dependent thermal contact leads to coupling of temperature and stress fields. Therefore, the inherent non-linearity of the problem demands simultaneous treating of both thermal and mechanical boundary integral equations while iterative procedures are introduced to ensure equilibrium of mechanical and thermal contact conditions at each step of the process. The transient behavior of interfacial cracks in bimaterial solids when undergo thermal shock in the presence of partial More >

R. Abdeljabar¹, F. Onofri², M.J. Safi¹

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.4, pp. 245-254, 2008, DOI:10.3970/fdmp.2008.004.245

Abstract This paper focuses on the mechanisms of convective instability in a stable salty gradient layer (i.e. an interfacial salty layer). This layer is assumed to be initially confined between two homogeneous liquid layers: a lower layer composed of salty water of 5wt% concentration and an upper layer composed of distilled water. The mechanisms underlying the interfacial salty layer's instability are depicted experimentally using a PIV technique and via measurements of concentration and temperature. It is found that in addition to the effect of double-diffusion across the interfacial salty layer, different forms of Kelvin-Helmholtz instability occur… More >

A. A. Nepomnyashchy^1,2, I. B. Simanovskii¹

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.3, pp. 185-198, 2008, DOI:10.3970/fdmp.2008.004.185

Abstract The development of instabilities under the joint action of the van der Waals forces and Marangoni stresses in a two-layer film on a heated or cooled substrate is considered. It is found that heating from below leads to the acceleration of the decomposition, decrease of the characteristic lateral size of structures, and the increase of the droplets heights. Heating from above leads to slowing down the instability rate and eventually to a complete suppression of the instability. More >

B. Yang², V. K. Tewary³

CMC-Computers, Materials & Continua, Vol.8, No.1, pp. 23-32, 2008, DOI:10.3970/cmc.2008.008.023

Abstract A three-dimensional Green's function for a material system consisting of anisotropic and linearly elastic planar multilayers with interfacial membrane and flexural rigidities has been derived. The Stroh formalism and two-dimensional Fourier transforms are applied to derive the general solution for each homogeneous layer. The Green's function for the multilayers is then solved by imposing the surface boundary condition, the interfacial displacement continuity condition, and the interfacial traction discontinuity condition. The last condition is given by the membrane and bending equilibrium equations of the interphases modeled as Kirchhoff plates. Numerical results that demonstrate the validity and More >