Ridha Djebali^1,2, Bernard Pateyron², Mohamed El Ganaoui³

CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.4, pp. 293-308, 2012, DOI:10.3970/cmes.2012.088.293

Abstract We present in this study a numerical investigation of unsteady two-dimensional natural convection of an electrically conducting fluid in a square cavity under an externally imposed magnetic field. A temperature gradient is applied between the two opposing side walls parallel to y-direction, while the floor and ceiling parallel to x-direction are adiabatic. The flow is characterized by the Rayleigh number Ra raged in 103-106, the Prandtl number Pr ranged in 0.01-10, the Hartman number Ha determined by the strength of the imposed magnetic field ranged in 0-100 and its tilting angle from x-axis ranging from… More >

Nadia Dihmani¹, Samir Amraqui¹, Ahmed Mezrhab^1,2, Najib Laraqi³

FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.3, pp. 311-322, 2012, DOI:10.3970/fdmp.2012.008.311

Abstract Natural convection with surface radiation heat transfer is investigated numerically in a vented vertical channel heated asymmetrically. The numerical solution is obtained using a finite volume method based on the SIMPLER algorithm for the treatment of velocity-pressure coupling. Concerning the radiation exchange, in particular, the working fluid is assumed to be transparent, so that only the solid surfaces (assumed diffuse-grey) give a contribute to such exchange. The effect of Rayleigh numbers and rib width (for Pr=0.7 air fluid) on the heat transfer and flow structure in the channel is examined in detail. Results are presented More >

Sangoju Bhaskar¹, Ravindra Gettu², B.H. Bharatkumar¹, M. Neelamegam¹

Structural Durability & Health Monitoring, Vol.7, No.4, pp. 231-252, 2011, DOI:10.3970/sdhm.2011.007.231

Abstract The durability of reinforced concrete (RC) exposed to severe environments depends largely on its ability to resist the penetration of aggressive compounds. This paper deals with the corrosion of reinforcement bars (rebars) in cracked concrete exposed to chlorides. A simple U-shaped specimen was used in the study, with a high yield strength deformed bar of 12 mm diameter placed at with 20 mm clear cover. Concrete specimens with three water to cement ratios (w/c) and pre-cracks exposed to chlorides were studied for quality assessment and quantifying the corrosion damage in terms of gravimetric weight loss. More >

J. H. Qiu^1,2, H. Jiang¹, H. L. Ji¹, N. Hu³

CMC-Computers, Materials & Continua, Vol.26, No.1, pp. 1-18, 2011, DOI:10.3970/cmc.2011.026.001

Abstract Piezoelectric actuators based motion-producing devices are widely used in precision machining, deformable mirrors, micropumps and piezoelectric injection systems. However, because of their hysteresis nonlinear property, the piezoelectric actuators can not provide absolutely precise displacements. To solve this problem, researchers applied inverse control method to compensate the nonlinearity of piezoelectric actuators, and the inverse models are mainly based on traditional hysteresis models such as the Preiasch model or Prandtl-Ishlinskii model. In this paper, a new approach for inverse control of piezoelectric actuators is presented. The new method utilize a modified Prandtl-Ishlinskii model which is based on More >

F.E. Mensah^∗,†, R. Sridhar^†, P. Misra^†

Molecular & Cellular Biomechanics, Vol.7, No.4, pp. 203-212, 2010, DOI:10.3970/mcb.2010.007.203

Abstract This work presents an overview of the use of liposomes for targeted delivery of photosensitizers to tumors for Photodynamic Therapy (PDT). It assesses the results of a quantitative model to explain the interaction of short-pulsed lasers (in the nanosecond and picosecond domains) with a liposome-dye complex in terms of a localized photo-induced thermal mechanism. Incorporation of an organic dye (sulforhodamine) within lipid vesicles has been investigated in conjunction with the effect of laser irradiation on the integrity of the liposome-dye complex. The variation of the absorption coefficient as a function of wavelength for dye-encapsulated liposomes More >

R. Martin¹, D. Komatitsch^1,2, S. D. Gedney³, E. Bruthiaux^1,4

CMES-Computer Modeling in Engineering & Sciences, Vol.56, No.1, pp. 17-42, 2010, DOI:10.3970/cmes.2010.056.017

Abstract Unsplit convolutional perfectly matched layers (CPML) for the velocity and stress formulation of the seismic wave equation are classically computed based on a second-order finite-difference time scheme. However it is often of interest to increase the order of the time-stepping scheme in order to increase the accuracy of the algorithm. This is important for instance in the case of very long simulations. We study how to define and implement a new unsplit non-convolutional PML called the Auxiliary Differential Equation PML (ADE-PML), based on a high-order Runge-Kutta time-stepping scheme and optimized at grazing incidence. We demonstrate More >

Smitha Gopinath¹, J. Rajasankar^1,2, Nagesh R. Iyer¹, T. S. Krishnamoorthy¹, B.H.Bharatkumar¹, N. Lakshmanan¹

Structural Durability & Health Monitoring, Vol.5, No.4, pp. 311-336, 2009, DOI:10.3970/sdhm.2009.005.311

Abstract In this paper, a two-phase strain-based constitutive model is proposed for concrete under tension. First phase deals with modelling uncracked concrete while the behaviour of concrete in cracked condition is modelled in second phase with appropriate theoretical support. A bilinear tension softening curve of concrete defined in crack width-stress space is taken as the basis to propose the model. Smeared representation of reinforcement and cracks along with multi-layered geometry definition of reinforced concrete (RC) structures is used to implement the model. Through this, it is shown that change in the orientation of tensile cracks with… More >

Sutthinane Nilbuaklee¹, Chanyut Kolitawong¹, Banpot Horbanluekit^1,2

The International Conference on Computational & Experimental Engineering and Sciences, Vol.13, No.1, pp. 4-10, 2009, DOI:10.3970/icces.2009.013.004

Abstract The purpose of this research is to determine fracture effects of vulcanize elastomer at various thickness to width ratios under opening mode fracture mechanics. The J-integral values from finite element method are compared with those from experiment. In this research, fracture tests perform under Single Edge Notch Tensile (S.E.N.T) tests using the multiple-specimen method. Compare to the experimental data, the numerical results are acceptable at the deep crack length, i.e. high crack length to width ratio. The k values from the 3-D numerical calculation show that thin sheet is dominated by plane stress state, but thick sheet More >

F. Keissarian¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.4, pp. 137-144, 2009, DOI:10.3970/icces.2009.012.137

Abstract In this paper, a new image compression technique is proposed in which variable block size technique is adopted, using quadtree decomposition, for coding images at low bit rates. The proposed algorithm decomposes the host image into blocks of variable sizes according to histogram analysis of the block residuals. Variable block sizes are then encoded at different rates based on their visual activity levels. To preserve edge integrity, a high-detail block is coded by a set of parameters associated with the pattern appearing inside the block. The use of these parameters at the receiver together with More >

Yufeng Nie¹, Ying Liu², Yuantong Gu³, Xiangkuo Fan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.45, No.1, pp. 31-56, 2009, DOI:10.3970/cmes.2009.045.031

Abstract The Node-based Local Mesh Generation (NLMG) algorithm, which is free of mesh inconsistency, is one of core algorithms in the Node-based Local Finite Element Method (NLFEM) to achieve the seamless link between mesh generation and stiffness matrix calculation, and the seamless link helps to improve the parallel efficiency of FEM. Furthermore, the key to ensure the efficiency and reliability of NLMG is to determine the candidate satellite-node set of a central node quickly and accurately. This paper develops a Fast Local Search Method based on Uniform Bucket (FLSMUB) and a Fast Local Search Method based More >