Sharif Digital Repository

Perovskite solar cells, with high efficiency operation, have been candidated as a cost-effective and environmentally friendly technology. Despite the great progress, there are some primarily issues remained regarding to the perovskite film and its fabrication methods. A very common perovskite cell structure is FTO/TiO2/CH3NH3PbI3/Spiro-OMeTAD/Au. Although, this structure has some advantages, lack of full surface coverage of perovskite film leads researchers to put much effort on finding other constructions. This surface inhomogeneity reduces the amount of light absorption and therefore efficiency. One way to produce a complete and uniform film is applying mixed-halide composition; such as... 

The microstructure, morphology and quality of the perovskite organic-inorganic layer as an absorber layer in perovskite solar cells has a significant role on the efficiency and energy conversion of the device. Different solvent engineering methods have been employed to prepare the perovskite layer with the desired properties and thier reproducibility have been studied. Herein, we applied a two-step solution approach by solvent engineering method, using solvents such as isopropyl alcohol, acetone and thier mixture, for preparation of lead iodide films. Moreover, their metallurgical and photovoltaic properties were investigated. The impact of solvent engineering, using solvents such as... 

Assessment of existing jacket type offshore platforms in Persian Gulf for life extension is of great importance in the field of offshore platforms in recent years. The main question to answer is whether an existing platform is safe enough to be used beyond the design life. Evaluation of existing jacket type offshore platforms under extreme environmental (wave) loading in Persian Gulf is a part of this major assessment. Two general approaches exist in this context, deterministic and probabilistic assessment. In this thesis, a new probabilistic method (reliability analysis) to assess offshore structures under environmental loading (extreme wave) is introduced. This method is a... 

By consideration of increasing demands to use implants and efforts to get technical knowledge and localization of this implants, considerable research in this field is needed. Therefore, presentation of a coating which is able to provide parameters needed for an acceptable implant is the aim of this study. In this direction, modification of surface of metallic implants in order to achieve nanotubes of titanium oxide, with the purpose of providing biocompatibility was done. On the other hand, because chronic infection of the implant’s surrounding is one of the main important reasons in rejection of implants, 〖TiO〗_2 nanotubes as a drug carrier were used in order to solve this problem. So,... 

Elastic joints in 2-mass drive systems, because of their limited stiffness, can decrease the performance of the control system and lead to motor and load speed oscillation. Shaft torque ignoring can also stress both mechanical and electrical drive components. Because of low degree of freedom, conventional controllers, such as the PI controllers, cannot improve the performance of the system and keep the system stable at the same time. In this thesis, the dynamic response and stability of the 2-mass systems is improved using state controller. State estimation of 2-mass system is required for state space controller . In the thesis, different state observer is analyzed and compared with each... 

Nanotechnology is an emerging field in technology that exploits the chemical and physical properties created by careful manipulation of materials at atomic and molecular levels. These properties lead to abilities created by this technology, which many scientists regard as the next industrial revolution. Although Nanotechnology promises bright future, today, researchers having learned from the history of technology are trying to predict its unwanted aspects and negative effects to decrease its potential issues. Researchers of Nano-ethics are trying to enable us to encounter Nanotechnology’s achievements in a reasonable way, by studying its ethical and social obligations. Since in our country,... 

Various types of tanks are used to store a variety of liquids, drinking water, chemicals, petrochemicals, and liquefied natural gas. Of these, one type is ‘elevated tank’ which is used to provide the required pressure for the water distribution systems rather than satisfying the water demand. Satisfactory performance of tanks during strong ground motions is crucial for modern facilities. Theoritical and experimental investigations of the dynamic behaviour of liquid storage tanks are conducted to seek possible improvments in the design of such tanks to resist earthquakes. The behaviour and performance of a new elevated tank was studied in this work. It was carried out through finite elements... 

In this study, a vapor-compression cooling system utilizing different PCMs has been studied whereby the electricity consumption peak load is shifted. More specifically, the dynamic performance of cooling systems with and without using PCM is evaluated for the hottest day of the year. The proposed system uses the cooling energy to freeze, or “discharge” the PCM during nighttime when the cooling load is minimally needed and uses the stored thermal energy during the peak load hours by melting, or “charging” the PCM. This leads to better performance during peak load hours when higher cooling loads are needed. Different PCMs including Oleic acid, SP224A, CL, CaCl2.6H2O have been investigated. The...