• Energy Research
• Persian close
• Tarbiat Modares University close

Environmental pollution and rapid depletion are among the chief concerns about fossil fuels such as oil, gas, and coal. Renewable energy sources do not suffer from such limitations and are considered the best choice to replace fossil fuels. The present study develops a mathematical model for optimal allocation of regional renewable energy to meet a country-wide demand and its other essential aspects. The ultimate purpose is to minimize the total cost by planning, including power plant construction and maintenance costs and transmission costs. Minimum-cost flow equations are embedded in the model to determine how regions can supply energy to other regions or rely on them to fulfill annual demand. In order to verify the applicability of the model, it is applied to a real-world case study of Iran to determine the optimal renewable energy generation-transmission decisions for the next decade. Results indicate that the hydroelectric and solar power plants should generate the majority of the generated renewable electricity within the country, according to the optimal solution. Moreover, regarding the significant population growth and waste generation in the country’s large cities, biomass power plants can have the opportunity to satisfy a remarkable portion of electricity demand.

Using of Nano-materials is one of the suitable ways for increasing of abiotic resistance in plants. In the current research, wild pear seedlings were irrigated with different concentrations of TiO2 and SiO2 NPs such as 0, 10, 100, 500 and 100 mgL-1. After this pretreatments, irrigation was stopped for 14 days to induce drought stress on the seedlings. At the end of the experiment, relative water content, xylem water potential, root biomass, electrolyte leakage rate, proline content and catalase enzyme activity were measured. The results showed that although both types of nanoparticles were differentially absorbed by roots of wild pear seedlings, the amelioration of water deficit in terms of all studied variables were observed for both of NPs with a slight differences between them. SiO2 NPs was more successful in improving root biomass and relative water content. On the other hand, TiO2 NPs was more successful in improving xylem water potential and catalase activity. Finally, amelioration effects of both NPs were clearly proved by the current research but further experiments are advised to find out involved mechanisms.