Comprehensive study on probability of controlling Caspian Sea invasive Ctenophora Activity 4: The laboratory study on probability of controlling Mnemiopsis leidyi by use of Beroe ovata (reproduction study of B. ovata in the Caspian Sea water)

In 1999 Mnemiopsis leidyi was introduced to the Caspian Sea from the Black Sea with ballast waters from the ships. The comprehensive study on probability of controlling Caspian Sea invasive Ctenophora planned after a remarkable of decreeing in Kilka fish catches stocks and fisheris community problems. This study focus on reproduction experiments of Beroe ovata as the best candidate for control of Mnemiopsis population size in the Caspian Sea that was performed in Turkey and Iran during 2002-2003. At 2002, 87 specimens of B. ovata, 10-50 mm transferred to Caspian sea ecology research center from Marmareh sea where acclimated with Caspian sea water gradually. At 2003, experiments were performed near to Black sea (at Sinop) with freshly collected Beroe ovata, 40-65 mm size in three salinity level treatment, the Black sea water 18 , Mixed water 15 and Caspian water 12 . 130 individuals of Beroe ovata were brought from Sinop (Turkey) to Iran during 2003. A number of Beroe specimens were sent to Guilan province for reproduction studies and another part were sent to Mazandaran province for both reproduction and mesocosem studies. For control we had 1 Beroe, length 30 mm in the Black Sea water that was alive during of study in Iran. The Jars were examined each day for ova and larvae and they were collected and put into glass container of Caspian water for hatching and developing survey, some of them were left without any handling for larvae developing. Also in another experiment the eggs collected from jars were placed in the same three treatments for studying of growth and survival. The results were unsuccessful on propagation experiments at 2002 since the spawning and hatching rates were very low (20 ova) and, none of the larvae developed into adults in Caspian Sea water. The spawning was more in Marmareh sea water with 138 ova where only 7 larvae was hatched. Results showed that Beroe specimens is able to survive and reproduce in Caspian water but was not as well as Black Sea also the Beroe larvae growth rate is low in the Caspian Sea water. Maximum fecundity of Beroe individual was 2212 and 235 ovae in Caspian Sea water in site Sinop and Iran respectively. Results showed 34-100% eggs in Caspian Sea water were destroyed and did not develop. In Iran we obtained only one larvae with 5 mm length, other larvae were at different stages of development but most of them were 1.2 2 mm. The results of mesocosm survey showed most of ova and larvae have been obtained from the tanks where individuals B. ovata were with Mnemiopsis. Fecundity of Beroe in the control with Black Sea water were between 17 to 1879 with average of 828 ± 112 ova. The poor results of B. ovata reproduction obtained in this survey in Caspian Sea may be due to transportation and acclimation stress and low salinity of Caspian Sea water

Generalized space vector controls for MLZSI

This paper proposes two advanced algorithms for multilevel Z-source inverter (MLZSI), which employ space vector control (SVC) as control algorithm of cascaded H-bridge multilevel Z-source inverter; where output voltage is achieved by summing the output voltages of bridge. In these algorithms different states to generate the same voltage with low THD, as the purpose, are verified and the suitable one is selected. This method is simple and has appropriate performance, where sample time is set quietly. Use of Z-network allows the inverter to generate a wide range of output voltage with high reliability. The accuracy of suggested algorithms is validated with simulation results using MATLAB/SIMULINK software and experimental results based PCI-1716 data acquisition system

Dynamic modeling of wind turbine based axial flux permanent magnetic synchronous generator connected to the grid with switch reduced converter

This paper studies the power electronic converters for grid connection of axial flux permanent magnetic synchronous generators (AFPMSG) based variable speed wind turbine. In this paper, a new variable speed wind turbine with AFPMSG and Z-source inverter is proposed to improve number of switches and topology reliability. Besides, dynamic modeling of AFPMSG is presented to analyze grid connection of the proposed topology. The Z-source inverter controls maximum power point tracking (MPPT) and delivering power to the grid. Therefore other DC–DC chopper is not required to control the rectified output voltage of generator in view of MPPT. As a result, the proposed topology requires less power electronic switches and the suggested system is more reliable against short circuit. The ability of proposed energy conversion system with AFPMSG is validated with simulation results and experimental results using PCI-1716 data acquisition system