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  • Open Access

    ABSTRACT

    Effect of the Reynolds Number on the Flow Pattern in a Stenotic Right Coronary Artery

    Biyue Liu1

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.1, pp. 35-40, 2007, DOI:10.3970/icces.2007.001.035

    Abstract It is well known that the Reynolds number has a significant effect on the blood flow in human arteries. We developed a three dimensional model with simplified geometry for a diseased right coronary artery segment to study the influence of the Reynolds number on the flow pattern in a stenotic coronary artery. Computations were carried out under physiological flow conditions to examine how the characteristics of the flow, such as the flow velocity and the pressure drop along the inner wall, change corresponding to the varying of the blood viscosity or to the varying of More >

  • Open Access

    ABSTRACT

    High-precision Path Prediction Simulation of Non-straight and High-speed Propagating Crack

    Nishioka T.1, Fujita N.1, Fujimoto T.1, Kogame M.1

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.3, pp. 127-132, 2007, DOI:10.3970/icces.2007.001.127

    Abstract In this study, numerical simulations of mixed-mode fracture paths in dynamic fracture phenomenon are carried out by using moving finite element method based on Delaunay automatic mesh generation. In addition, the experiments under same condition was carried out, and the both results were compared. The calculated paths by the simulation agree well with the fracture paths of the experiments. More >

  • Open Access

    ARTICLE

    Two-Layer Passive/Active Anisotropic FSI Models with Fiber Orientation: MRI-Based Patient-Specific Modeling of Right Ventricular Response to Pulmonary Valve Insertion Surgery

    Dalin Tang*, Chun Yang, Tal Geva‡,§, Pedro J. del Nido

    Molecular & Cellular Biomechanics, Vol.4, No.3, pp. 159-176, 2007, DOI:10.3970/mcb.2007.004.159

    Abstract A single-layer isotropic patient-specific right/left ventricle and patch (RV/LV/Patch) combination model with fluid-structure interactions (FSI) was introduced in our previous papers to evaluate and optimize human pulmonary valve replacement/insertion (PVR) surgical procedure and patch design. In this paper, an active anisotropic model with two-layer structure for ventricle wall and tissue fiber orientation was introduced to improve previous isotropic model for more accurate assessment of RV function and potential application in PVR surgery and patch design. A material-stiffening approach was used to model active heart contraction. The computational models were used to conduct ``virtual (computational)'' surgeries More >

  • Open Access

    ARTICLE

    Structural Analysis of the Right Rear Lug of American Airlines Flight 587*

    I.S. Raju1, E.H. Glaessgen1, B.H. Mason1, T. Krishnamurthy1, C.G. Davila1

    CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.1, pp. 1-30, 2007, DOI:10.3970/cmes.2007.022.001

    Abstract A detailed finite element analysis of the right rear lug of the American Airlines Flight 587 - Airbus A300-600R was performed as part of the National Transportation Safety Board's failure investigation of the accident that occurred on November 12, 2001. The loads experienced by the right rear lug were evaluated using global models of the vertical tail, local models near the right rear lug, and a global-local analysis procedure. The right rear lug was analyzed using two modeling approaches. In the first approach, solid-shell type modeling was used, and in the second approach, layered-shell type… More >

  • Open Access

    ARTICLE

    Weight Function Shape Parameter Optimization in Meshless Methods for Non-uniform Grids

    J. Perko1, B. Šarler2

    CMES-Computer Modeling in Engineering & Sciences, Vol.19, No.1, pp. 55-68, 2007, DOI:10.3970/cmes.2007.019.055

    Abstract This work introduces a procedure for automated determination of weight function free parameters in moving least squares (MLS) based meshless methods for non-uniform grids. The meshless method used in present work is Diffuse Approximate Method (DAM). The DAM is structured in 2D with the one or two parameter Gaussian weigh function, 6 polynomial basis and 9 noded domain of influence. The procedure consists of three main elements. The first is definition of the reference quality function which measures the difference between the MLS approximation on non-uniform and hypothetic uniform node arrangements. The second is the… More >

  • Open Access

    ARTICLE

    Weight Optimization of Skeletal Structures with Multi-Point Simulated Annealing

    L. Lamberti1,2, C. Pappalettere1,3

    CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.3, pp. 183-222, 2007, DOI:10.3970/cmes.2007.018.183

    Abstract This paper presents a novel optimization algorithm for minimizing weight of skeletal structures. The algorithm--denoted as MPISA (Multi Point Improved Simulated Annealing)--utilizes a multi-level simulated annealing scheme where different candidate designs are compared simultaneously. This is done in purpose to increase computational efficiency and to minimize the number of exact structural analyses.
    MPISA is tested in three complicated design problems of skeletal structures: (i) sizing optimization of a planar bar truss under five independent loading conditions including 200 design variables; (ii) sizing-configuration optimization of a cantilevered bar truss including 81 design variables; (iii) sizing-configuration optimization More >

  • Open Access

    ARTICLE

    Spectral Element Approach for Inverse Models of 3D Layered Pavement

    Chun-Ying. Wu1, R. Al-Khoury2, C. Kasbergen2, Xue-Yan. Liu2, A. Scarpas2

    CMES-Computer Modeling in Engineering & Sciences, Vol.17, No.3, pp. 163-172, 2007, DOI:10.3970/cmes.2007.017.163

    Abstract 3D spectral element method in the article is presented to predict the pavement layer modules using field measurement of Falling Weight Deflectometer (FWD). To improve the computational efficiency of the layer-condition assessment, one type of spectral element is proposed to develop the dynamic analysis of 3D multi-layered system subjected to an impulsive load. Each layer in structure is simulated as two-noded layer spectral element or one-noded spectral element in frequency domain. In order to identify the parameters of layered structures, a nonlinear optimization method called Powell hybrid algorithm is employed. The optimization procedure is performed More >

  • Open Access

    ARTICLE

    Prediction of Springback in Straight Flanging using Finite Element Method

    S. K. Panthi1,2, N. Ramakrishnan2, K. K. Pathak2, J. S. Chouhan3

    CMC-Computers, Materials & Continua, Vol.6, No.1, pp. 13-20, 2007, DOI:10.3970/cmc.2007.006.013

    Abstract One of the important features of flanging process is elastic recovery during unloading leading to springback. The elastic recovery is associated with various tool and material parameters. It is difficult to analytically predict the elastic recovery accurately owing to the complex material deformation behavior. In this investigation, a commercially available Finite Element software is used for elasto-plastic analysis of flanging process. The springback is studied varying geometrical, material and friction parameters. The results of the simulation are validated with a few published experimental results. More >

  • Open Access

    ARTICLE

    How to Achieve Kronecker Delta Condition in Moving Least Squares Approximation along the Essential Boundary

    Jin Yeon Cho1

    CMC-Computers, Materials & Continua, Vol.5, No.2, pp. 99-116, 2007, DOI:10.3970/cmc.2007.005.099

    Abstract A novel way is proposed to fulfill Kronecker delta condition in moving least squares (MLS) approximation along the essential boundary. In the proposed scheme, the original MLS weight is modified to boundary interpolatable (BI) weight based on the observation that the support of weight function is exactly the same as the support of MLS nodal shape function. The BI weight is zero along the boundary edges except the edges containing the nodal point associated with the concerned weight. In order to construct the BI weight from the original weight, concept of edge distance function is… More >

  • Open Access

    ARTICLE

    Expression of human telomerase reverse transcriptase, Suroivin, DD3 and PCGEM1 messenger RNA in archival prostate carcinoma tissue

    Hanna Bialkowska-Hobrzanska, David K. Driman, Robert Fletcher, Vimla Harry, Hassan Razvi

    Canadian Journal of Urology, Vol.13, No.1, pp. 2967-2974, 2006

    Abstract Background: The variable clinical behavior displayed by prostate cancer (PCa) warrants investigation of potential PCa-specific biomarkers that could identify more aggressive tumor types and therefore provide prognostic value. Upregulation of expression of human telomerase reverse transcriptase (hTERT), Survivin, DD3 and PCGEM1 mRNAs in PCa lesions has recently been described. The purpose of this study was to evaluate the clinical value of detection of overexpression of these biomarkers in the diagnosis and prognosis of PCa.
    Material and methods: Archival formalin-fixed, paraffin-embedded (FFPE) prostatectomy tissue from 26 patients with PCa (Gleason score 3-9, mean 7) and 14 patients with… More >

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