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Showing 2 results for Aghnia
Volume 20, Issue 6 (11-2018)
Abstract
Gully erosion affects soil properties in different ways. One of the most important effects of gully erosion is destruction of soil structure and reducing its quality. The objective of this research was to study the effects of gully development on soil properties and quality indices in areas adjacent to the gullies. For this purpose, 15 soil properties and 5 soil quality indices including Integrated Quality Index (IQI), Nemero Quality Index (NQI), Cumulative Rating (CR), and Sustainability Index (SI) were compared between gully wall and outside gully lands in three sites of Ardabil province, northwestern Iran. T-test method with three replications was used for comparison. The results showed that in all three sites, 8 out of 15 soil properties changed near the gully walls, mainly indicating the reduction of soil structure, organic carbon, and S index (slope of retention curve at inflection point) and increasing the Cation Ratio Of soil Structural Stability (CROSS) and soil erodibility index. Also, near the gullies, most of the soil quality indices decreased due to gully development in the study sites. Therefore, gully formation and development in these sites reduced soil quality near the gully walls.
M. Sedighi, M. Aelaei, M. Aghnia,
Volume 20, Issue 6 (June 2020)
Abstract
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.
