Sharif Digital Repository

The role of natural gas compressor stations, is to maintain the gas pressure at the level required for gas transportation along the pipeline to the distribution system. In Iran, residential heating demand, has a large share in natural gas consumption. Thus the demand of natural gas would be greater in cold winter days in comparison to other seasons. Due to this intense demand fluctuations, geographical diversity of demand, long distances between supply and demand points, supply and demand mismatches and long term investment, there is an intense reliability and load factor issues within these systems operations. In this thesis, natural gas compressor stations are modeled and installation and... 

New electric Unmanned Aerial Vehicles (UAV) has unconventional methods for design and performance analyzing. Using the electric power sources and reduce power with time, cause to confusion about operating this type of planes, so new optimization methods are generated. This methods, can used for some part of flight and special problems and involve some assumptions. One of these new methods is using Singular Perturbation theory for prediction optimal path trajectory of Aerial Vehicles. In this research, we solve the optimal climb trajectory for an electric UAV in rested (no wind) atmosphere. Solution of this problem, involve some parameters such as velocity, altitude and flight path angle with... 

The objective of this thesis is to evaluate and calibrate design load combinations of steel building structures of Iran based on the reliability theory. The importance of this research stems from recognition that the design load combinations for steel structures in Section 6 of the National Building Code of Iran have been completely adopted from the ASCE/SEI 7-10 standard, whereas the factors that affect these load combinations differ in Iran from those of the United States. Examples are the difference in the construction industry economy, lower quality of here and the differences in probability distributions for the specifications of steel. Hence, the load combinations need to be calibrated... 

Increasing electric energy consumption has necessitated long term planning of power generation based on the concept of least cost planning. Minimization of energy supply and optimization of technology mix had been considered as the main objective functions. But issues on the energy productivity, demand side management, externalities and internalizing external costs have dominated energy scheme which has lead to the development of comprehensive criteria such as Integrated Resource Planning (IRP) and Total Resource Cost (TRC). In these cases it is aimed to develop a comprehensive view of the energy planning that may include the case of DSM and externalities. The objective of the present... 

In previous decades, easy access to material and low cost human power allow the product process to be performed in a preferred way. The limit in amount of material, economy, and the efficiency of the model has not been influential like these days. Today, the effective use of material and consideration of an economic model have great importance. It is obvious that a process of designing implies optimizing which the range of its using is also continuing in many engineering sciences. Many optimization issues contain discrete nature. Many of searching spaces that we encounter in the real world applications are not necessarily continuous as a condition which has crucial importance for classic... 

The purpose of the current study is to design an optimal trajectory and control for an aircraft to perform a microgravity maneuver automatically. This subject is by itself an important research topic that has not yet been attempted via optimal control formulation and modelling. Space stations are commonly utilized to conduct long-term microgravity research. Unfortunately utility of space stations to perform space based microgravity experiments is expensive and inaccessible for many researchers and scientific institutions. However, since many experiments requiring microgravity conditions can be performed in short time intervals, there is a possibility to meet their demand via optimal... 

Due to the environmental problems of lead and the prohibition of its use, lead-free piezoceramic sodium-potassium niobate, KNN, are one of the main candidates to replace lead-containing piezoceramics, PZTs. High Curie temperature, low density, and compatibility with nickel electrodes are its distinguishing features from other piezoelectric materials. The crystal structure of this material varies with temperature and includes rhombohedral, orthorhombic, tetragonal, and cubic. Various synthesis and manufacturing methods including hydrothermal, solid-state reaction, sol-gel, molten salt, etc. are used for this material. In this research, the hydrothermal synthesis method is used due to its high...