This study was conducted to determine the temporal and spatial distribution of Opusia indica in the Hara Biosphere Reserve in the Persian Gulf. Seasonal sampling (four seasons) was performed from winter 2019 to autumn 2019. Sampling was done in five regions and three habitats within each region using metal quadrats with dimensions of 25 × 25 cm. In each habitat, environmental parameters including temperature, salinity, dissolved oxygen, pH along with organic matter and grain size were measured. The results showed that the abundance and biomass of Opusia indica have decreasing trend with increasing habitat complexity. Seasonally, the highest abundance and biomass were observed in winter and autumn, respectively, and the lowest abundance and biomass were observed in spring. There was a significant difference between habitats and seasons (p <0.05). Salinity showed a significant difference between habitats but didn't have seasonal changes. While temperature didn't show a significant difference between habitats, but it had seasonal changes. There was a significant difference between dissolved oxygen levels and pH between habitats and seasons. Significant changes were observed between habitat and seasons in sediment grain size, while the amount of organic matter showed only differences between habitats. Also, analysis of Kendall correlation between environmental factors (temperature, salinity, dissolved oxygen and pH) with abundance and biomass showed that there was a significant correlation between these environmental factors but no significant correlation was observed between abundance and biomass with the amount of organic matter. The results help to better understand the situation of this species in the mangroves ecosystem.

Fuel system is one of the most important parts of the micro gas turbine. Due to the variation of environmental conditions such as temperature, relative humidity of air and height in different geographical locations, the operational features of the fuel system change. In this study, the fuel system of the GTCP85-180 gas turbine is modelled by applying PID mechanical controller. The governing equations of the controller is coupled with classical thermodynamic equations of the gas turbine and the effects of different environmental conditions on start-up and norminal operation of the motor are investigated. The range of variations of the environmental conditions is choosed by considering the geographical locations of Iran. The results of the numerical simulation were verified by comparing the numerical results obtained with written code in Matlab software with experimental measurements. The results showed that the environmental temperature has the strongest effect on the operational features of the fuel control system and causes 16.3% variation of exhaust gas temperature, 3.7% variation of fuel discharge, 14.7% variation of start-up time of the motor and 4.7% variation of fuel pressure in injectors. Also, the start-up operation of the motor showed more sensitivity to environmental conditions compared to normal operation of micro gas turbine.