Abel Ferreira

Learn More
[1] While many earthquakes have now been studied using interferometric synthetic aperture radar (InSAR) data, a full assessment of the quality and additional value of InSAR source parameters compared to seismological techniques is still lacking. We compile a catalog of source models obtained using InSAR and estimate the corresponding centroid moment tensor(More)
This paper describes the operation and control of Modular Multilevel Converter (MMC). The converter current controllers were designed with different bandwidth ranges. Different operating conditions for the controllers led to different responses and its impact was evaluated. Simulation results of a 5MW grid connected to the MMC illustrate the good dynamic(More)
[1] We carry out long‐period surface wave centroid moment tensor (CMT) inversions using various global tomographic models and two different forward modeling techniques for 32 large earthquakes previously studied using interferometric synthetic aperture radar (InSAR) data. Since InSAR methods provide an alternative and independent way of locating and(More)
Several MMC models are present in the literature. The suitable converter model used depends on the studies that must be performed. The work presents a simplified electrical equivalent model for the Modular Multilevel Converter (MMC) which can be used for ac power flow and fault studies. The total energy that is stored in the MMC submodules is modelled as an(More)
This work reports and discusses the influence of four phosphonium-based ionic liquids (PhILs), namely trihexyl(tetradecyl) phosphonium dicyanamide, [P(6,6,6,14)][dca]; trihexyl(tetradecyl) phosphonium bis(trifluoromethylsulfonyl)imide, [P(6,6,6,14)][Tf(2)N]; tetrabutyl phosphonium bromide, [P(4,4,4,4)][Br]; and tetrabutyl phosphonium chloride,(More)
In spite of their interest, viscosities of fluorocarbon compounds are scarce, and the available data are unreliable and of poor accuracy. In this work, viscosity measurements of linear, cyclic, aromatic, and R-substituted perfluorocarbons were carried out in the temperature range between (298.15 and 318.15) K using an Ubbelohde viscometer. The experimental(More)
The knowledge of biodiesel density over large ranges of temperature and pressure is important for predicting the behavior of fuel injection and combustion systems in diesel engines, and for the optimization of such systems. In this study, cottonseed oil was transesterified into biodiesel and its density was measured at temperatures between 288 K and 358 K(More)
  • 1