The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Maria Da Guia Da Silva - One of the best experts on this subject based on the ideXlab platform.

  • voltage stability probabilistic assessment in composite systems modeling unsolvability and controllability loss
    IEEE Transactions on Power Systems, 2010
    Co-Authors: A B Rodrigues, R B Prada, Maria Da Guia Da Silva
    Abstract:

    Several papers have recognized the effect of uncertainties in voltage stability analysis through probabilistic Methods. In these papers, the unstable states are generally identified by the unsolvability of the power flow equations or by violations in the voltage stability margin limit. However, voltage stability problems may also be associated with a loss in voltage controllability, when a voltage control action has an effect which is contrary to what is usually expected. The main aim of this paper is to include unstable states caused by unsolvability and voltage controllability loss in the voltage stability probabilistic assessment. This goal is achieved through the combination of three techniques: the Monte Carlo Simulation Method, the nonlinear optimal power flow and the D' matrix Method. These three techniques permit the inclusion of a new issue in the computation of voltage instability risk: the unstable states stemming from controllability loss.

A B Rodrigues - One of the best experts on this subject based on the ideXlab platform.

  • voltage stability probabilistic assessment in composite systems modeling unsolvability and controllability loss
    IEEE Transactions on Power Systems, 2010
    Co-Authors: A B Rodrigues, R B Prada, Maria Da Guia Da Silva
    Abstract:

    Several papers have recognized the effect of uncertainties in voltage stability analysis through probabilistic Methods. In these papers, the unstable states are generally identified by the unsolvability of the power flow equations or by violations in the voltage stability margin limit. However, voltage stability problems may also be associated with a loss in voltage controllability, when a voltage control action has an effect which is contrary to what is usually expected. The main aim of this paper is to include unstable states caused by unsolvability and voltage controllability loss in the voltage stability probabilistic assessment. This goal is achieved through the combination of three techniques: the Monte Carlo Simulation Method, the nonlinear optimal power flow and the D' matrix Method. These three techniques permit the inclusion of a new issue in the computation of voltage instability risk: the unstable states stemming from controllability loss.

Dezső Boda - One of the best experts on this subject based on the ideXlab platform.

  • multiscale analysis of the effect of surface charge pattern on a nanopore s rectification and selectivity properties from all atom model to poisson nernst planck
    Journal of Chemical Physics, 2019
    Co-Authors: Monika Valisko, Bartlomiej Matejczyk, Zoltan Hato, Tamas Kristof, Eszter Madai, David Fertig, Dirk Gillespie, Dezső Boda
    Abstract:

    We report a multiscale modeling study for charged cylindrical nanopores using three modeling levels that include (1) an all-atom explicit-water model studied with molecular dynamics, and reduced models with implicit water containing (2) hard-sphere ions studied with the Local Equilibrium Monte Carlo Simulation Method (computing ionic correlations accurately), and (3) point ions studied with Poisson-Nernst-Planck theory (mean-field approximation). We show that reduced models are able to reproduce device functions (rectification and selectivity) for a wide variety of charge patterns, that is, reduced models are useful in understanding the mesoscale physics of the device (i.e., how the current is produced). We also analyze the relationship of the reduced implicit-water models with the explicit-water model and show that diffusion coefficients in the reduced models can be used as adjustable parameters with which the results of the explicit- and implicit-water models can be related. We find that the values of the diffusion coefficients are sensitive to the net charge of the pore but are relatively transferable to different voltages and charge patterns with the same total charge.We report a multiscale modeling study for charged cylindrical nanopores using three modeling levels that include (1) an all-atom explicit-water model studied with molecular dynamics, and reduced models with implicit water containing (2) hard-sphere ions studied with the Local Equilibrium Monte Carlo Simulation Method (computing ionic correlations accurately), and (3) point ions studied with Poisson-Nernst-Planck theory (mean-field approximation). We show that reduced models are able to reproduce device functions (rectification and selectivity) for a wide variety of charge patterns, that is, reduced models are useful in understanding the mesoscale physics of the device (i.e., how the current is produced). We also analyze the relationship of the reduced implicit-water models with the explicit-water model and show that diffusion coefficients in the reduced models can be used as adjustable parameters with which the results of the explicit- and implicit-water models can be related. We find that the values of t...

R B Prada - One of the best experts on this subject based on the ideXlab platform.

  • voltage stability probabilistic assessment in composite systems modeling unsolvability and controllability loss
    IEEE Transactions on Power Systems, 2010
    Co-Authors: A B Rodrigues, R B Prada, Maria Da Guia Da Silva
    Abstract:

    Several papers have recognized the effect of uncertainties in voltage stability analysis through probabilistic Methods. In these papers, the unstable states are generally identified by the unsolvability of the power flow equations or by violations in the voltage stability margin limit. However, voltage stability problems may also be associated with a loss in voltage controllability, when a voltage control action has an effect which is contrary to what is usually expected. The main aim of this paper is to include unstable states caused by unsolvability and voltage controllability loss in the voltage stability probabilistic assessment. This goal is achieved through the combination of three techniques: the Monte Carlo Simulation Method, the nonlinear optimal power flow and the D' matrix Method. These three techniques permit the inclusion of a new issue in the computation of voltage instability risk: the unstable states stemming from controllability loss.

Yan Levin - One of the best experts on this subject based on the ideXlab platform.

  • Simulations of Polyelectrolyte Adsorption to a Dielectric Like-Charged Surface.
    The journal of physical chemistry. B, 2016
    Co-Authors: Alexandre P. Dos Santos, Matheus Girotto, Yan Levin
    Abstract:

    We explore, using the recently developed efficient Monte Carlo Simulation Method, the interaction of an anionic polyelectrolyte solution with a like-charged dielectric surface. In addition to polyions, the solution also contains salt with either monovalent, divalent, or trivalent counterions. In agreement with recent experimental observations, we find that multivalent counterions can lead to strong adsorption of polyions onto the surface. On the other hand, addition of a 1:1 electrolyte diminishes the adsorption induced by the multivalent counterions. Dielectric discontinuity at the interface is found to play only a marginal role in polyion adsorption.