Andres F. Osorio¹, Ruben Osorio¹, Reginald Tran¹, Andres Ceballos¹, Alain Kassab¹, Eduardo Divo², I. Ricardo Argueta-Morales³, William M. DeCampli^3,4

The International Conference on Computational & Experimental Engineering and Sciences, Vol.15, No.4, pp. 123-124, 2010, DOI:10.3970/icces.2010.015.123

Abstract Presently, mechanical support is the most promising alternative to cardiac transplantation. Ventricular Assist Devices (VADs) were originally used to provide mechanical circulatory support in patients waiting planned heart transplantation (“bridge-to-transplantation” therapy). The success of short-term bridge devices led to clinical trials evaluating the clinical suitability of long-term support (“destination” therapy) with left ventricular assist devices (LVADs). The first larger-scale, randomized trial that tested long-term support with a LVAD reported a 44% reduction in the risk of stroke or death in patients with a LVAD. In spite of the success of LVADs as bridge-to-transplantation and long-term… More >

He Gong^∗,†, Ming Zhang^‡

Molecular & Cellular Biomechanics, Vol.7, No.1, pp. 1-12, 2010, DOI:10.3970/mcb.2010.007.001

Abstract In mechanical disuse conditions associated with immobilization and microgravity in spaceflight, cortical endosteal surface moved outward with periosteal surface moving slightly or unchanged, resulting in reduction of cortical thickness. Reduced thickness of the shaft cortex of long bone can be considered as an independent predictor of fractures. Accordingly, it is important to study the remodeling process at cortical endosteal surface. This paper presents a computer simulation of cortical endosteal remodeling induced by mechanical disuse at the Basic Multicellular Units level with cortical thickness as controlling variables. The remodeling analysis was performed on a representative rectangular… More >

Anant Diwakar¹, D. N.Srinath¹, Sanjay Mittal¹

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.1, pp. 61-90, 2010, DOI:10.3970/cmes.2010.069.061

Abstract Aerodynamic shape optimization of airfoils is carried out for two values of Reynolds numbers: 10³ and 10⁴, for an angle of attack of 5^o. The objective functions used are (a) maximization of lift (b) minimization of drag and (c) minimization of drag to lift ratio. The surface of the airfoil is parametrized by a 4^th order non-uniform rational B-Spline (NURBS) curve with 61 control points. Unlike the efforts in the past, the relatively large number of control points used in this study offer a rich design shape with the possibility of local bumps and valleys on the… More >

Jong Keun Moon¹, Seung Jo Kim²

CMES-Computer Modeling in Engineering & Sciences, Vol.67, No.3, pp. 239-264, 2010, DOI:10.3970/cmes.2010.067.239

Abstract Large structural problems with high precision and complexity require a high-performance computation using the efficient parallel algorithm. The purpose of this paper is to present the parallel performance of thermal-structural coupled analysis tested on a parallel cluster system. In the coupled analysis, the heat transfer analysis is carried out, and then the structural analysis is performed based on temperature distribution. For the automatic and efficient connection of two parallel analysis modules, the several communication patterns were studied. The parallel performance was demonstrated for the sample and the real application problems, such as a laminated composite More >

Peter Lucas¹, Alexander H. van Zuijlen¹, Hester Bijl¹

CMES-Computer Modeling in Engineering & Sciences, Vol.59, No.1, pp. 79-106, 2010, DOI:10.3970/cmes.2010.059.079

Abstract Despite the advances in computer power and numerical algorithms over the last decades, solutions to unsteady flow problems remain computing time intensive.
In previous work [Lucas, P.,Bijl, H., and Zuijlen, A.H. van(2010)], we have shown that a Jacobian-free Newton-Krylov (JFNK) algorithm, preconditioned with an approximate factorization of the Jacobian which approximately matches the target residual operator, enables a speed up of a factor of 10 compared to nonlinear multigrid (NMG) for two-dimensional, large Reynolds number, unsteady flow computations. Furthermore, in [Lucas, P., Zuijlen, A.H. van, and Bijl, H. (2010)] we show that this algorithm also greatly… More >

G.C. Bourantas¹, E.D. Skouras^2,3, V.C. Loukopoulos⁴, G.C. Nikiforidis¹

CMES-Computer Modeling in Engineering & Sciences, Vol.59, No.1, pp. 31-64, 2010, DOI:10.3970/cmes.2010.059.031

Abstract A meshfree point collocation method has been developed for the velocity-vorticity formulation of two-dimensional, steady state incompressible Navier-Stokes equations. Particular emphasis was placed on the application of the velocity-correc -tion method, ensuring the continuity equation. The Moving Least Squares (MLS) approximation is employed for the construction of the shape functions, in conjunction with the general framework of the point collocation method. Computations are obtained for regular and irregular nodal distributions, stressing the positivity conditions that make the matrix of the system stable and convergent. The accuracy and the stability of the proposed scheme are demonstrated More >

Sujoy Mukherjee¹, Ranjan Ganguli^1,2

CMC-Computers, Materials & Continua, Vol.19, No.2, pp. 105-134, 2010, DOI:10.3970/cmc.2010.019.105

Abstract In this study, variational principle is used for dynamic modeling of an Ionic Polymer Metal Composite (IPMC) flapping wing. The IPMC is an Electro-active Polymer (EAP) which is emerging as a useful smart material for `artificial muscle' applications. Dynamic characteristics of IPMC flapping wings having the same size as the actual wings of three different dragonfly species Aeshna Multicolor, Anax Parthenope Julius and Sympetrum Frequens are analyzed using numerical simulations. An unsteady aerodynamic model is used to obtain the aerodynamic forces. A comparative study of the performances of three IPMC flapping wings is conducted. Among More >

Liviu Marin¹

CMC-Computers, Materials & Continua, Vol.17, No.3, pp. 233-274, 2010, DOI:10.3970/cmc.2010.017.233

Abstract We investigate two algorithms involving the relaxation of either the given boundary temperatures (Dirichlet data) or the prescribed normal heat fluxes (Neumann data) on the over-specified boundary in the case of the iterative algorithm of Kozlov91 applied to Cauchy problems for two-dimensional steady-state anisotropic heat conduction (the Laplace-Beltrami equation). The two mixed, well-posed and direct problems corresponding to every iteration of the numerical procedure are solved using the method of fundamental solutions (MFS), in conjunction with the Tikhonov regularization method. For each direct problem considered, the optimal value of the regularization parameter is chosen according More >

Zone-Ching Lin¹and Ren-Yuan Wang¹

CMC-Computers, Materials & Continua, Vol.16, No.3, pp. 247-272, 2010, DOI:10.3970/cmc.2010.016.247

Abstract The paper establishes a new three-dimensional quasi-steady molecular statics nanoscale abrasive cutting model to investigate the abrasive cutting behavior in the downpressing and abrasive cutting process of a workpiece in chemical mechanical polishing (CMP) process. The downpressing and abrasive cutting process is a continuous process. The abrasive cutting process is done after the single abrasive particle has downpressed and penetrated a workpiece to a certain depth of a workpiece. The paper analyzes the effects of the abrasive particles with different diameters on action force. It also analyzes the action force change of abrasive particles with… More >

Robert E. Verloop¹, Pieter Koolwijk¹, Anton Jan van Zonneveld², Victor W. M. van Hinsbergh¹

European Cytokine Network, Vol.20, No.4, pp. 207-219, 2009, DOI:10.1684/ecn.2009.0174

Abstract Since the initial discovery of endothelial progenitor cells (EPC), and their promise in increasing angiogen-esis and vasculogenesis, a myriad of papers have highlighted their potential application in experimental and clinical neo-vascularization and in tissue engineering. However, promising reports are contrasted by other studies that could not find a role for EPC in neovascularization. Presently, two types of endothelial progenitor cell populations are recognized. The first population provides early-outgrowth CD34⁺ /VEGFR-2⁺ cells, or colony-forming unit endothelial cells (CFU-EC), which represent myeloid cells with some endothelial properties, but no ability to form endothelial colonies. They can stimulate neovascularization… More >