Effects of binary mixtures of ionic/nonionic (sodium dodecyl sulfate/2-heptanol or 1-decanol) and nonionic/nonionic surfactants (2-heptnol/1-decanol) on drop/interface COALESCENCE of water drops in a continuous n-heptane phase were examined. The drop size reduced appreciably and the multi-step COALESCENCE was suppressed finally as the concentration of each of the constituting components of surfactant mixture was increased. The drop became more stable in comparison to single surfactant systems. It was concluded that the mixed surfactants were much more effective on COALESCENCE time and drop lifetime than single surfactant, particularly when one of the components was soluble in the drop phase.

In order to investigate the effects of drop size and its falling distance on drop interface COALESCENCE time, the so-called COALESCENCE cell had been designed and built. The selected chemical materials were as follows: Water-Toluene, Water normal Heptanes and 60% aqueous Glycerol-Toluene. In all experiments, the oil phase was as continuous phase. Before each run, the two immiscible phases were mutually saturated by mixing and then, separated from each other. It was indicated that, the increasing of drop diameter or drop falling distance increases drop interface COALESCENCE time, separately. These factors also cause the subsidence of MULTISTEP COALESCENCE phenomena in water-Toluene system, which has usually occurred severely. Added to these, the vertical or horizontal fluctuations of drop on interface, causes the delaytion of drop COALESCENCE.

Background and Objectives: To overcome the disadvantages of the traditional two-level inverters, especially in electric drive applications, multi-level inverters (MLIs) are the widely accepted solution. Diode-Clamped Inverters (DCIs) are a well-known structure of multi-level inverters. In DCIs, the voltage balance of the DC-link capacitors and the Common Mode (CM) voltage reduction are two important criteria that should be considered. Methods: This paper concentrates on the current control of 3-phase 4-level DCI with finite control set model predictive control (MPC) strategy. Current tracking performance, DC-link capacitor voltage balance, switching frequency minimization, and CM voltage control have been considered in the objective function of the MPC. Moreover, the MULTISTEP prediction method has been applied to improve the performance of the DCI. Results: The effectiveness of the proposed MULTISTEP prediction control for the 4-level DCI has been evaluated with different horizon lengths. Moreover, the effect of several values of weighting factors has been studied on the system behavior. Conclusion: Results validate the accuracy of current tracking and voltage balancing in the suggested MULTISTEP MPC for the 4-level DCI. In addition, CM voltage control and switching frequency reduction can be included in the predictive control. Decreasing the CM voltage and switching frequency will oppositely affect the dynamic behavior and voltage balancing of the DCI. Therefore, selection of weighting factors depends on the system needs and requirements.

1. Introduction: In the present paper, the ability of the Artificial Neural Network (ANN) and combined wavelet-neural network (WANN) model were investigated for MULTISTEP modeling of hydroclimatic processes with the least input. For this purpose, the ANN model and then the WANN model were used to predict one to twelve steps in advance. Finally, the efficiencies of all models were examined using the evaluation criteria, and all models were compared with each other. . .