Aerospace Science and Technology
Ali Mirzaee kahagh; Alireza Sekhavat Benis
Abstract
The current research was conducted with the aim of identifying the role of unmanned aerial vehicles in future smart cities. The current research was conducted in terms of mixed statistical methods (qualitative-quantitative). The participants of the qualitative part, which was implemented based on the ...
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The current research was conducted with the aim of identifying the role of unmanned aerial vehicles in future smart cities. The current research was conducted in terms of mixed statistical methods (qualitative-quantitative). The participants of the qualitative part, which was implemented based on the method of thematic analysis, were 14 knowledgeable experts, including specialized and experienced managers in the fields of urban security, transportation, road, and urban development, aviation organization and aviation industry, and The Information and Communication Technology Organization of Greater Tehran cities until reaching theoretical saturation and in the quantitative part, all the expert experts of the relevant devices were 134 people, and using Cochran's formula and targeted sampling method, the number of 99 people was were selected as sample members. The reliability coefficient of the qualitative part was recorded by the method of two coders with the final result (83%) and the reliability of the quantitative part was recorded with Cronbach's alpha coefficient with the final result (0.91). MAXQDA software was used for qualitative data analysis and SPSS software was used for quantitative data analysis. The findings showed that in the process of explaining the role of unmanned aerial vehicles in future smart cities; There are 5 comprehensive themes, 16 organizing themes, and 58 basic themes. The results showed that unmanned aerial vehicles can play a significant role in creating future smart cities through 1- intelligent air transportation, 2- agile monitoring and inspection, 3- smart agriculture, 4- smart urban and citizen services, and 5- smart law enforcement.
Aerospace Science and Technology
Alireza Sekhavat Benis; Reza Aghaei Togh
Volume 16, Issue 1 , June 2023, , Pages 146-158
Abstract
The compressor blade is responsible for increasing the flow pressure. By adding a blade behind the main blade, the compressor performance can be improved by increasing the pressure ratio and reducing the weight. The tandem improves the performance and increases the compressor absorption coefficient by ...
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The compressor blade is responsible for increasing the flow pressure. By adding a blade behind the main blade, the compressor performance can be improved by increasing the pressure ratio and reducing the weight. The tandem improves the performance and increases the compressor absorption coefficient by increasing the pressure ratio, preventing flow separation and controlling the boundary layer. This has led compressor designers to seek to reduce weight, increase pressure ratio and increase efficiency by using tandem. The geometry of the compressor blade and stage along with its tandem has been obtained from previous valid sources and has been drawn in three dimensions and numerically analyzed. Then the various parameters for the blade and the tandem are examined separately and the pressure and velocity vectors are plotted to show the control of the vortices, which results in improved compressor performance. The characteristic curve of the compressor and the pressure ratio for this particular tandem are also plotted at the end. Calculations show that by using the tandem and removing the excess vortex after the main blade, we will see a 28.5% increase in total pressure, a 15% decrease in relative mach number and a 1.5% decrease in entropy.
