The Experts below are selected from a list of 414411 Experts worldwide ranked by ideXlab platform

Didier Smets - One of the best experts on this subject based on the ideXlab platform.

Dominik Schotzau - One of the best experts on this subject based on the ideXlab platform.

  • Energy norm a posteriori error estimation for hp adaptive discontinuous galerkin methods for elliptic problems in three dimensions
    2011
    Co-Authors: Stefano Giani, Paul Houston, Dominik Schotzau
    Abstract:

    We develop the Energy norm a posteriori error estimation for hp-version discontinuous Galerkin (DG) discretizations of elliptic boundary-value problems on 1-irregularly, isotropically refined affine hexahedral meshes in three dimensions. We derive a reliable and efficient indicator for the error measured in terms of the Natural Energy norm. The ratio of the efficiency and reliability constants is independent of the local mesh sizes and weakly depending on the polynomial degrees. In our analysis we make use of an hp-version averaging operator in three dimensions, which we explicitly construct and analyze. We use our error indicator in an hp-adaptive refinement algorithm and illustrate its practical performance in a series of numerical examples. Our numerical results indicate that exponential rates of convergence are achieved for problems with smooth solutions, as well as for problems with isotropic corner singularities.

  • Energy norm a posteriori error estimation for divergence free discontinuous galerkin approximations of the navier stokes equations
    2008
    Co-Authors: Guido Kanschat, Dominik Schotzau
    Abstract:

    We develop the Energy norm a posteriori error analysis of exactly divergence-free discontinuous RTk/Qk Galerkin methods for the incompressible Navier–Stokes equations with small data. We derive upper and local lower bounds for the velocity–pressure error measured in terms of the Natural Energy norm of the discretization. Numerical examples illustrate the performance of the error estimator within an adaptive refinement strategy. Copyright © 2008 John Wiley & Sons, Ltd.

Fabrice Bethuel - One of the best experts on this subject based on the ideXlab platform.

Hao Zhang - One of the best experts on this subject based on the ideXlab platform.

  • direct powering a real cardiac pacemaker by Natural Energy of a heartbeat
    2019
    Co-Authors: Feng Xie, Yue Huang, Yingwei Tian, Xiaoxue Dong, Yang Liu, Xin Shao, Lei Jin, Jingquan Liu, Bin Yang, Hao Zhang
    Abstract:

    Implantable medical devices are widely used for monitoring and treatment of severe diseases. In particular, an implantable cardiac pacemaker is the most effective therapeutic device for treating bradyrhythmia, however its surgical replacement is inevitable every 5–12 years due to the limited life of the built-in battery. Although several approaches of Energy harvesting have been explored in this decade for powering cardiac pacemakers, the modern, commercial, and full-function pacemaker has never been powered effectively yet. Here, we report an integrated strategy for directly powering a modern and full-function cardiac pacemaker, which can pace the porcine heart in vivo by harvesting the Natural Energy of a heartbeat, without using any external Energy storage element. The generator includes an elastic skeleton and two piezoelectric composites, which could generate a high-output current of 15 μA in vivo over state-of-the-art performance. This study makes an impressive step toward fabricating a self-powered...

Noriko Kawakami - One of the best experts on this subject based on the ideXlab platform.

  • development of a 500 kw modular multilevel cascade convertor for battery Energy storage systems
    2013
    Co-Authors: Noriko Kawakami, Satoru Ota, Hironobu Kon, Shuji Konno, Hirofumi Akagi, Hiromu Kobayashi, Naotaka Okada
    Abstract:

    Natural Energy sources such as wind turbines and photovoltaic power generators cause instability of the power grid due to their output fluctuations. Battery Energy storage systems (BESSs) are being considered as a countermeasure for this issue. A Modular Multilevel Cascade Convertor (MMCC) is one suitable circuit topology for BESSs, because each cell can control each battery's state-of-charge independently, and the level of generated harmonics is low enough to eliminate the AC filter normally installed in conventional two level converters. This paper describes the development of a real-scale (500 kW) H-bridge MMCC for BESSs and reports successful test results of the control functions with a scale down grid model and a 6.6-kV real-scale distribution line.

  • overview of battery Energy storage systems for stabilization of renewable Energy in japan
    2012
    Co-Authors: Noriko Kawakami, Yukihisa Iijima
    Abstract:

    Natural Energy generators such as wind turbines and photovoltaics cause instability of the power grid due to their output fluctuations. Battery Energy storage systems are being considered as a countermeasure for this issue. This paper gives an overview of battery Energy storage systems used for stabilizing the output fluctuations of Natural Energy generators in Japan. Some verification test results are also shown.