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  • Open Access

    ARTICLE

    Large-Scale Parallel Finite Element Analyses of High Frequency Electromagnetic Field in Commuter Trains

    A. Takei1, S. Yoshimura1, H. Kanayama2

    CMES-Computer Modeling in Engineering & Sciences, Vol.31, No.1, pp. 13-24, 2008, DOI:10.3970/cmes.2008.031.013

    Abstract This paper presents large-scale finite element analyses of high frequency electromagnetic fields in commuter trains. The ADVENTURE_Magnetic is one of the main modules of the ADVENTURE system, which is an open source parallel finite element analyses system, and is able to solve eddy current and magnetostatic problems using the hierarchical domain decomposition method (HDDM) with an iterative linear algebraic solver. In this paper, we improve the module so as to solve a high frequency electromagnetic field of 500-1000 M[Hz]. A stationary Helmholtz equation for electromagnetic wave problems is solved taking an electric field as an More >

  • Open Access

    ARTICLE

    Time Variant Reliability Analysis of Nonlinear Structural Dynamical Systems using combined Monte Carlo Simulations and Asymptotic Extreme Value Theory

    B Radhika1, S S P,a1, C S Manohar1,2

    CMES-Computer Modeling in Engineering & Sciences, Vol.27, No.1&2, pp. 79-110, 2008, DOI:10.3970/cmes.2008.027.079

    Abstract Reliability of nonlinear vibrating systems under stochastic excitations is investigated using a two-stage Monte Carlo simulation strategy. For systems with white noise excitation, the governing equations of motion are interpreted as a set of Ito stochastic differential equations. It is assumed that the probability distribution of the maximum in the steady state response belongs to the basin of attraction of one of the classical asymptotic extreme value distributions. The first stage of the solution strategy consists of selection of the form of the extreme value distribution based on hypothesis tests, and the next stage involves More >

  • Open Access

    ARTICLE

    Modeling Helicopter Rotor Blade Flapping Motion Considering Nonlinear Aerodynamics

    Jyoti Ranjan Majhi, Ranjan Ganguli1

    CMES-Computer Modeling in Engineering & Sciences, Vol.27, No.1&2, pp. 25-36, 2008, DOI:10.3970/cmes.2008.027.025

    Abstract The flapping equation for a rotating rigid helicopter blade is typically derived by considering 1) small flap angle, 2) small induced angle of attack and 3) linear aerodynamics. However, the use of nonlinear aerodynamics can make the assumptions of small angles suspect. A general equation describing helicopter blade flap dynamics for large flap angle and large induced inflow angle of attack is derived in this paper with nonlinear aerodynamics . Numerical simulations are performed by solving the nonlinear flapping ordinary differential equation for steady state conditions and the validity of the small angle approximations are More >

  • Open Access

    ARTICLE

    The Stochastic α Method: A Numerical Method for Simulation of Noisy Second Order Dynamical Systems

    Nagalinga Rajan, Soumyendu Raha1

    CMES-Computer Modeling in Engineering & Sciences, Vol.23, No.2, pp. 91-116, 2008, DOI:10.3970/cmes.2008.023.091

    Abstract The article describes a numerical method for time domain integration of noisy dynamical systems originating from engineering applications. The models are second order stochastic differential equations (SDE). The stochastic process forcing the dynamics is treated mainly as multiplicative noise involving a Wiener Process in the Itô sense. The developed numerical integration method is a drift implicit strong order 2.0 method. The method has user-selectable numerical dissipation properties that can be useful in dealing with both multiplicative noise and stiffness in a computationally efficient way. A generalized analysis of the method including the multiplicative noise is More >

  • Open Access

    ARTICLE

    Three-dimensional Simulations of Water-Mercury Anticonvection

    Thomas Boeck1, Alexander Nepomnyashchy2,3, Ilya Simanovskii2

    FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.1, pp. 11-20, 2008, DOI:10.3970/fdmp.2008.004.011

    Abstract Anticonvection in a two-layer system of mercury and water is studied using three-dimensional direct numerical simulations with a Fourier-Chebyshev spectral method. The two fluid layers have equal thicknesses and are uniformly heated from above. Interface deformations and surface tension gradients are neglected. The quiescent state is replaced by steady hexagons upon increasing the heating from above. We investigate the destabilization of this primary convective pattern in a small and in a large computational domain upon increasing the temperature difference across the two fluid layers. For the large domain the convection cells become disordered at about More >

  • Open Access

    ARTICLE

    Peridynamic Simulation of Electromigration

    Walter Gerstle1, Stewart Silling2, David Read3, Vinod Tewary4, Richard Lehoucq5

    CMC-Computers, Materials & Continua, Vol.8, No.2, pp. 75-92, 2008, DOI:10.3970/cmc.2008.008.075

    Abstract A theoretical framework, based upon the peridynamic model, is presented for analytical and computational simulation of electromigration. The framework allows four coupled physical processes to be modeled simultaneously: mechanical deformation, heat transfer, electrical potential distribution, and vacancy diffusion. The dynamics of void and crack formation, and hillock and whisker growth can potentially be modeled. The framework can potentially be applied at several modeling scales: atomistic, crystallite, multiple crystallite, and macro. The conceptual simplicity of the model promises to permit many phenomena observed in microchips, including electromigration, thermo-mechanical crack formation, and fatigue crack formation, to be More >

  • Open Access

    LETTER

    Re: Mechanical failure rate of da Vinci robotic system

    Paolo Pierini and Emanuele Baldassarre

    Canadian Journal of Urology, Vol.14, No.6, pp. 3726-3726, 2007

    Abstract This article has no abstract. More >

  • Open Access

    ARTICLE

    Chlorination: Phytotoxicity and effects on the production and quality of Lactuca sativa var. Mantecosa grown in a closed, soil-less system

    Premuzic1 Z, HE Palmucci1, J Tamborenea1, M Nakama2

    Phyton-International Journal of Experimental Botany, Vol.76, pp. 103-117, 2007, DOI:10.32604/phyton.2007.76.103

    Abstract The addition of chlorine constitutes an economical disinfection method for closed, soil-less systems. Three quantities of sodium hypochlorite (0.55, 5.5 and 11 ppm) were applied to closed, soil-less greenhouse- grown lettuce (Lactuca sativa), to study the effect on its production (fresh weight and dry matter) and some commercial and nutritional quality factors (phytotoxicity, Vitamin C, nitrates). Sodium hypochlorite was weekly added within the nutrient solution, and the chemical properties (pH, EC and chlorides) of the recycled solution were measured. Damage to leaves was evaluated 15 days before harvest. Chlorination produced different effects regarding both production and… More >

  • Open Access

    ARTICLE

    Technical Note : Prolonged exposure of human embryonic stem cells to heat shock induces necrotic cell death

    B.C. Heng*, K.J. Vinoth*, K. Lu*, X. Deng*, Z. Ge*, B.H. Bay**, T. Cao*

    BIOCELL, Vol.31, No.3, pp. 405-410, 2007, DOI:10.32604/biocell.2007.31.405

    Abstract We investigated the effects of prolonged heat shock treatment on human embryonic stem cell (hESC) viability. The hESC viability steadily declined with longer exposure to heat shock treatment (43ºC). After 4 h of exposure to heat shock at 43ºC, only 56.2 ± 1.5% of cells were viable. Viability subsequently declined to 37.0 ± 3.3% and 3.5 ± 0.7% after 8 h and 16 h, respectively of heat shock treatment at 43ºC. Transmission electron micrographs showed that the morphology of the dead/dying cells after heat shock treatment was characteristic of cellular necrosis with an uncondensed chromatin… More >

  • Open Access

    ARTICLE

    Immunophenotypic evaluation, and physiological and laboratory correlations of hematopoietic stem cells from umbilical cord blood

    R. Canabarro1,2, H. Sporleder2, T. Gomes3,4, G. Zanatta3,5, L. Scribel3,6, F. Freitas7, J. Neumann2, P. Pranke1,3

    BIOCELL, Vol.31, No.3, pp. 397-403, 2007, DOI:10.32604/biocell.2007.31.397

    Abstract The use of umbilical cord blood stem cells is an efficient alternative for the transplantation of hematopoietic progenitor cells. A number of factors can influence the volume and amount of CD34+ cells, which are considered as immature and capable of proliferation. Quantification of CD34+ cells, evaluation of CD38 and c-kit molecules on these cells, as well as correlations of such factors as maternal age, gestational age, newborn sex and weight, umbilical cord length, placental weight with increased volume and concentration of immature cells, among others, were performed in 70 blood samples from term newborns. The mean… More >

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