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Comparison of the Different Classical Structural Optimization Methods and Algorithms
, M.Sc. Thesis Sharif University of Technology ; Joghataei, Abdolreza (Supervisor)
Abstract
In this thesis, the classical methods of structural optimization were studied and compared. After a comprehensive study on different methods of structural optimization, a reduced number of methods were selected in order to be used in this research. Exterior penalty function method, linear and quadratic extended penalty function methods were the selected constrained optimization methods. For unconstrained optimization, univariate method, Powell method, steepest descent method, Fletcher-Reeves method, and quasi-Newton methods of DFP and BFGS were used. And from different one-dimensional search methods studied, we used the golden section method. The structures which were optimally designed by...
Design and Construction of a 100 We Solar Dish Stirling and Evaluation for the Regional Conditions of Tehran
, M.Sc. Thesis Sharif University of Technology ; Boroushaki, Mehrdad (Supervisor) ; Sattari, Sorena (Co-Advisor) ; Hooshang, Mazdak (Co-Advisor)
Abstract
Dish-stirling system with an efficiency of nearly 30% is the most efficient technology among solar energy technologies. This system includes four main parts; Parabolic dish, solar tracker, receiver and Stirling engine and generator. In this system, first parabolic dish concentrates sun rays on its focus. A receiver is put on the focus to receive the heat radiated from dish. This receiver transfers the heat to a Stirling engine. In Stirling engine, expansion and contraction of gas helps piston to move and finally rotational mechanical work is done. With coupling a generator and Stirling engine we can generate electricity. Also for keeping the focus of sun rays on receiver we should have sun...
Air Pollution Effects on Mortality
, M.Sc. Thesis Sharif University of Technology ; Rahmati, Mohammad Hossein (Supervisor) ; Vesal, Mohammad (Supervisor)
Abstract
In this paper evaluate the short-term effects of air pollution on the mortality rate caused by cardiovascular problems, respiratory problems, digestive problems and tumors and cancers. This is done by using daily mortality data of Tehran, Tabriz, Mashad, Shiraz, Ahwaz and Isfahan during the years 1390 to 1394, we also use daily measurements of pollutant levels including Carbon-monooxcide, Sulfure-dioxide, Oxides of Nitrogen, Ozone and Particulate matters in the same period. The effects are estimad by looking at the relation of daily mortality in each city along with its pollution level. By controling for the weather conditions and city and month fixed effects, we find significant positive...
IGBT open-circuit fault diagnosis in a Quasi-Z-source inverter
, Article IEEE Transactions on Industrial Electronics ; Volume 66, Issue 4 , 2019 , Pages 2847-2856 ; 02780046 (ISSN) ; Shokrollahi Moghani, J ; Noroozi, N ; Zolghadri, M. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
In this paper, a fast and practical method is proposed for open-circuit (OC) fault diagnosis (FD) in a three-phase quasi-Z-source inverter (q-ZSI). Compared to the existing fast OC FD techniques in three-phase voltage-source inverters (VSIs), this method is more cost-effective since no ultra-fast processor or high-speed measurement is required. Additionally, the method is independent of the load condition. The proposed method is only applicable to Z-source family inverters and is based on observing the effect of shoot-through (SH) intervals on the system variables during switching periods. The proposed algorithm includes two consecutive stages: OC detection and fault location identification....