Four Phase Relative Permeability and Capillary Pressure Framework for Surfactant EOR Simulation

Consistent set of algorithms to calculate phase relative permeability and capillary pressure values in the four-phase representation suitable for surfactant flooding simulation has been derived. The novel formulation resolves difficulties with applying existing three-phase approaches, and it ensures continuity of transport characteristics at solubilization changes in phase composition.

Asymptotic Behavior of Boson Regge Trajectories

The asymptotic behavior of boson Regge trajectories is studied. Upper and lower bounds on the asymptotic growth of the trajectories are obtained using the phase representation for the trajectories and a number of physical requirements. It is shown that, within the assumptions made, the asymptotic behavior of the trajectories is a square root.

An Analytical Model for Small Signal Stability Analysis in Unbalanced Electrical Power Systems

This paper presents a general model to carry out a small signal stability analysis in electrical power systems (EPSs) that operate in unbalanced conditions. The classic traditional approach is based on a phase representation where it is supposed that the triphasic electric grid does not suffer any variations during its operation. With the presence of unbalances in transmission lines and loads, it is necessary to develop a general model that allows answering the needs and challenges with which modern electric systems must deal. The present work firstly intends to address the three-phase representation of an EPS, including the controllers. The proposed model is applied to a classical test system, a three machine-nine bus system, considering all the dynamic and algebraic variations associated with angular stability analysis. The proposed approach to small signal stability analysis shows results that differ from the classical analysis. The results are backed up with time domain simulations, and therefore, these results could be used in the calculation of the controllers that operate in unbalanced multimachine systems.