Sharif Digital Repository

The life prediction of equipments guarantees reliable, safe, efficient and continuous operation of thermal power plants. In this paper wall thickness of reheater tubes of boiler number 3 of Neka power plant in north of Iran are measured at several points during maintenance shut down periods. Thickness dependency vs. time has been investigated. Artificial Neural Network (ANN) as a tool has been acquired to determine this dependency. Extrapolation of thickness function vs. time applying maximum normal stress criteria results in corresponding thickness. The maximum wall reduction rates have been calculated by two schemes namely Fuzzy function (FF) and Neural Network (ANN) applying numerical... 

Arbuscular mycorrhizal (AM) fungi are non-specific symbionts developing mutual and beneficial symbiosis with most terrestrial plants. Because of the obligatory nature of the symbiosis, the presence of the host plant during the onset and proceeding of symbiosis is necessary. However, AM fungal spores are able to germinate in the absence of the host plant. The fungi detect the presence of the host plant through some signal communications. Among the signal molecules, which can affect mycorrhizal symbiosis are plant hormones, which may positively or adversely affect the symbiosis. In this review article, some of the most recent findings regarding the signaling effects of plant hormones, on...