the structure and the electronic properties of single-walled zigzag bn and b3c2n3 nanotubes (n, 0; n=4–10) were investigated using first-principles calculations based on a density functional theory. a plane–wave basis set with periodic boundary conditions in conjunction with vanderbilt ultrasoft pseudo-potential was employed. the energy gap of zb3c2n3nts was calculated and compared with the cor...

due to shortage of precipitation and the spatial and periodical disparity of rainfalls, iran iscounted among the arid and semi-arid countries of the world, and therefore the water utilities have put thecontrol of consumption and efficient use of water high on their priorities. water consumption management isconsidered as a field of energy management, and the impacts of effective measure related...

Wheat is the dominant cereal crop constituting the first staple food in Iran. This paper studies the energy consumption patterns and the relationship between energy inputs and yield for Wheat production in Iranian agriculture during the period 1986 – 2008. The results indicated that total energy inputs in irrigated and dryland wheat production increased from 29.01 and 9.81 GJ ha-1 in 1986 to 44...

globally excessive consumption of hydrocarbon fuel in transport sector is a serious threat to the civilization due to paucity of fuel in future. also this growing use of vehicles for transport is contributing about 70% of total air pollution and causing environmental and ecological imbalances. thus the worldwide fast depletion of conventional energy resources and impact of emissions on environm...