This paper presents the second-order sliding mode controller (SOSMC) of a micro-positioning stage piezoelectric model actuator (PEA), where the C-H model parameters are adopted to describe the hysteresis behavior and identified through particle swarm optimization. In this technique, two control algorithms are developed. The first one is the so-called twisting algorithm (TA). The control appears explicitly in the second surface derivative, and in a discontinuous control action that ensures a sliding regime mode. The second one, the super twisting algorithms (STA) has been developed and analyzed for systems. The use of both algorithms gives a significant reduction in chattering as compared to the standard sliding mode control. It is shown that the STA case offers better performances than TA. Simulation results are presented to demonstrate the advantage of SOSMC over SMC.

In this work, the modeling and the sliding mode control of a self-excited asynchronous generator integrated in a wind energy conversion system is studied. The dc-link voltage and frequency output by the wind turbine depend on the wind intensity applied to the turbine and load. The goal of the study is to increase energy quality and to achieve a stabilization of dc-link voltage and frequency values based on sliding mode control. This method offers stability and robustness against external disturbances. However, this method is based in the power converter to improve the excellent dynamic of wind energy conversion system to meet the connection to the main grid. The simulation results show the efficiency and reliability of the proposed control method.

In this work, the modeling and the sliding mode control of a self-excited asynchronous generator integrated in a wind energy conversion system is studied. The dc-link voltage and frequency output by the wind turbine depend on the wind intensity applied to the turbine and load. The goal of the study is to increase energy quality and to achieve a stabilization of dc-link voltage and frequency values based on sliding mode control. This method offers stability and robustness against external disturbances. However, this method is based in the power converter to improve the excellent dynamic of wind energy conversion system to meet the connection to the main grid. The simulation results show the efficiency and reliability of the proposed control method.

In this work, the modeling and the sliding mode control of a self-excited asynchronous generator integrated in a wind energy conversion system is studied. The dc-link voltage and frequency output by the wind turbine depend on the wind intensity applied to the turbine and load. The goal of the study is to increase energy quality and to achieve a stabilization of dc-link voltage and frequency values based on sliding mode control. This method offers stability and robustness against external disturbances. However, this method is based in the power converter to improve the excellent dynamic of wind energy conversion system to meet the connection to the main grid. The simulation results show the efficiency and reliability of the proposed control method.

The Mexa and Bougous dams were built to control river floods and supply crop-irrigation and drinking water. This study aimed to characterize the hydrogeochemical state in the region containing the dams, which influences the quality of the waters and thus their suitability for agricultural use, given the extent of the river networks that naturally transport sediments and pollutants into the reservoirs via streams. Thus, some physicochemical and organic parameters, including electrical conductivity, calcium, magnesium, sodium, potassium, chloride, bicarbonate, sulfate, biological oxygen demand, nitrite, ammonium, and phosphate, were used as benchmarks to examine the stiffness of the water pollution. Sampling was carried out during May and September of 2011 and 2012. The obtained results showed that, according to the Stiff diagram, the dominant hydrogeochemical facies is calcium bicarbonate in waters that do not have calcium levels in excess of 3 meq/l and bicarbonate levels in excess of 2.4 meq/l. The organic pollution index disclosed that the waters have evolved from a moderate to a high degree of organic pollution due to the accumulation of pollutants and nutrients from waste disposal and fertilizers. The samples fell into the C2-S1 class in the Richards diagram; this implies that the waters are suitable for plants that are salt tolerant, but that the use of these waters can cause problems for clay soils. However, in the long term, irrigation with the dam waters may pose difficulties for agriculture due to the resulting increase in the electrical conductivity of the soil. This study concludes that water salinity and alkalinity affect crop suitability, meaning that the temporal monitoring of water quality is needed to avoid adverse consequences for crop production.

The Mexa and Bougous dams were built to control river floods and supply crop-irrigation and drinking water. This study aimed to characterize the hydrogeochemical state in the region containing the dams, which influences the quality of the waters and thus their suitability for agricultural use, given the extent of the river networks that naturally transport sediments and pollutants into the reservoirs via streams. Thus, some physicochemical and organic parameters, including electrical conductivity, calcium, magnesium, sodium, potassium, chloride, bicarbonate, sulfate, biological oxygen demand, nitrite, ammonium, and phosphate, were used as benchmarks to examine the stiffness of the water pollution. Sampling was carried out during May and September of 2011 and 2012. The obtained results showed that, according to the Stiff diagram, the dominant hydrogeochemical facies is calcium bicarbonate in waters that do not have calcium levels in excess of 3 meq/l and bicarbonate levels in excess of 2.4 meq/l. The organic pollution index disclosed that the waters have evolved from a moderate to a high degree of organic pollution due to the accumulation of pollutants and nutrients from waste disposal and fertilizers. The samples fell into the C2-S1 class in the Richards diagram; this implies that the waters are suitable for plants that are salt tolerant, but that the use of these waters can cause problems for clay soils. However, in the long term, irrigation with the dam waters may pose difficulties for agriculture due to the resulting increase in the electrical conductivity of the soil. This study concludes that water salinity and alkalinity affect crop suitability, meaning that the temporal monitoring of water quality is needed to avoid adverse consequences for crop production.

The Mexa and Bougous dams were built to control river floods and supply crop-irrigation and drinking water. This study aimed to characterize the hydrogeochemical state in the region containing the dams, which influences the quality of the waters and thus their suitability for agricultural use, given the extent of the river networks that naturally transport sediments and pollutants into the reservoirs via streams. Thus, some physicochemical and organic parameters, including electrical conductivity, calcium, magnesium, sodium, potassium, chloride, bicarbonate, sulfate, biological oxygen demand, nitrite, ammonium, and phosphate, were used as benchmarks to examine the stiffness of the water pollution. Sampling was carried out during May and September of 2011 and 2012. The obtained results showed that, according to the Stiff diagram, the dominant hydrogeochemical facies is calcium bicarbonate in waters that do not have calcium levels in excess of 3 meq/l and bicarbonate levels in excess of 2.4 meq/l. The organic pollution index disclosed that the waters have evolved from a moderate to a high degree of organic pollution due to the accumulation of pollutants and nutrients from waste disposal and fertilizers. The samples fell into the C2-S1 class in the Richards diagram; this implies that the waters are suitable for plants that are salt tolerant, but that the use of these waters can cause problems for clay soils. However, in the long term, irrigation with the dam waters may pose difficulties for agriculture due to the resulting increase in the electrical conductivity of the soil. This study concludes that water salinity and alkalinity affect crop suitability, meaning that the temporal monitoring of water quality is needed to avoid adverse consequences for crop production.

The Mexa and Bougous dams were built to control river floods and supply crop-irrigation and drinking water. This study aimed to characterize the hydrogeochemical state in the region containing the dams, which influences the quality of the waters and thus their suitability for agricultural use, given the extent of the river networks that naturally transport sediments and pollutants into the reservoirs via streams. Thus, some physicochemical and organic parameters, including electrical conductivity, calcium, magnesium, sodium, potassium, chloride, bicarbonate, sulfate, biological oxygen demand, nitrite, ammonium, and phosphate, were used as benchmarks to examine the stiffness of the water pollution. Sampling was carried out during May and September of 2011 and 2012. The obtained results showed that, according to the Stiff diagram, the dominant hydrogeochemical facies is calcium bicarbonate in waters that do not have calcium levels in excess of 3 meq/l and bicarbonate levels in excess of 2.4 meq/l. The organic pollution index disclosed that the waters have evolved from a moderate to a high degree of organic pollution due to the accumulation of pollutants and nutrients from waste disposal and fertilizers. The samples fell into the C2-S1 class in the Richards diagram; this implies that the waters are suitable for plants that are salt tolerant, but that the use of these waters can cause problems for clay soils. However, in the long term, irrigation with the dam waters may pose difficulties for agriculture due to the resulting increase in the electrical conductivity of the soil. This study concludes that water salinity and alkalinity affect crop suitability, meaning that the temporal monitoring of water quality is needed to avoid adverse consequences for crop production.