Sharif Digital Repository

In this thesis, the multidisciplinary design of liquid propellant satellite launch vehicle has been done by taking into consideration the effects of fuel sloshing. At first, the theory of multidisciplinary design and one-level architecture with the label of multidisciplinary feasibility have been used. In the following, Gravitational Search Algorithm (GSA) and Particle swarm optimization (PSO) have been developed. Then, the multidisciplinary design cycle began with the design of the liquid propellant system. In the propulsion section, the selection of the optimal fuel, the design of the nozzle, motor and the selection of the optimal engine cycle considering the geometric and mass... 

In general, the output power of the gas turbines decreases as the ambient temperature increases. One of the ways to deal with such a performance loss is to use a wet compression system, which reduces the air temperature rise throughout the compressor. In this system, the water droplets are injected into the compressor inlet and evaporated throughout the stages. As a result, the work of the compressor decreases, and the power and efficiency of the whole engine increase. Most of the researchers in this field have tried to develop mathematical models to investigate the effects of this system on compressor and gas turbine performance in steady-state conditions. However, it is necessary to... 

The Reconfigurable manufacturing system (RMS) was first introduced in 1996 with the ability to respond quickly to market changes and in response to global competition between companies. The effort of this research is to expand the problem presented in the Moghaddam et al. (2019) by introducing the concept of raw materials for the production of parts and related issues such as purchasing and warehousing raw materials, and providing a suitable solution to the problem. In the basic article, the RMS should utilize the best combination of machines and their configurations in proportion to the demand of the products in order to minimize the cost and produce all the demand. In this study, a large... 

Increase in growing concerns over environmental pollution and depletion of fossil fuel resources motivate the need for cleaner energy technologies and stimulate research in facilitating renewable energy systems. In recent years, photovoltaic systems have attracted great attention since they remove the need for energy storage systems and intermediate processess for energy conversion. However, high capital cost, low efficiency and low energy density per area of these systems, as compared with other technologies hinder its industrial use. To surmount these bottlenecks and improve technical performance of PV systems, it is crucial to optimize configuration of convertor connection and to improve... 

In recent years, the use of fiber reinforced polymer (FRP) jackets, as an external lateral confinement has found considerable attention in retrofitting and strengthening existing reinforced concrete (RC) columns in earthquake prone areas. The FRP composites have numerous advantages such as ease in application, high strength and stiffness-weight ratio, no corrosion and negligible changes in the member dimension. Most of previous studies have concentrated on evaluation of the effect of confinement with spiral bars or FRP composites, separately. However, in practice both types of confinements exist in strengthening RC columns.
This paper presents the results of a computational modeling to... 

Different data sources are creating a huge amount of data at increasing speeds that require real-time processing. Such data is called “Big data stream". Although, mining and analysis this type of data is so useful for companies, but it also may cause many privacy breaches. The principle issues for big data stream’ anonymization are real time processing and information loss. There are some works that are proposed for data streams, but they have some drawbacks such as inefficient anonymization of big data stream and also not consider time expiration of tuples that lead to increase the information loss and cost of the data publishing. In this thesis, in order to speed up the ability of big data... 

Multi-Criteria Decision-Making models have been considered by many researchers in recent years. In this study, considering the transition matrix, the probability of changing in the priories of the customers in the framework of a hybrid QFD-ANP has been proposed. The developed methodology is implemented to solve the supplier selection problem, one of the most important problems in the supply chain management, in a dairy manufacturer in Iran. The company is one of the most prominent companies that has a big segment of the dairy market. The results show the efficiency of the proposed methodology for multi-criteria decision-making problems.• Chapter 1) General research reasons for the purpose... 

Cryptocurrency miners by solving complex mathematical calculations are responsible for verifying the transactions made in the blockchain network as well as maintaining its security, and as a reward for these activities, they receive bitcoins from the network. The devices used to mine cryptocurrency in order to perform the aforementioned calculations need high electricity consumption, so that the main cost of mining is related to its electricity consumption. For this reason, the ever-increasing development of the blockchain network, as well as the significant growth of the value of Bitcoin, has increased the number of cryptocurrency miners, especially in countries with low electricity costs.... 

The power systems’ net-load variability and uncertainty would aggravate significantly as the penetration of Renewable Energy Resources (RERs) in power systems increases. In response, power system researchers have introduced a new concept, namely flexibility, to quantitatively and systematically deal with unavoidable features of RERs. In power distribution systems as the connection point of power systems with customers, there are many opportunities for improving the flexibility level of systems. Nowadays, the emergence of prosumers has created new opportunities for distribution system operators in providing the system with different services of flexibility in distribution systems. Therefore,... 

In this thesis, the bidding strategy of prosumers in transactive energy markets is analyzed. Considering the repaid increase in utilizing installations that convert multiple energy together, the concept of multi-carrier energy studies has been highlighted. Moreover, with the advent of district heating networks, thermal energy markets have gained much attention lately. The agent who participates in such markets can appropriately benefit from the inherent interdependencies between various energy carriers depending on their prices in different energy markets. This market player is technically called to pose an energy hub. In this regard, to deploy the inherent abilities of such an energy... 

The issue of loss allocation is one of the most important issues that has long been considered in electricity networks, including distribution and transmission. With changes in distribution networks over the years and the penetration of distributed energy sources, the allocation of losses has become more of a challenge than ever before. Hence, there is a need for a loss allocation algorithm that can be implemented in any network and with any topology. In this dissertation, a new, simple and at the same time efficient algorithm for allocating real losses in all networks (distribution - transmission) and with any structure (radial - circular) is presented. This algorithm first tracks the... 

With the growing population and the development of human societies, the demand for energy increases. And it is expected that for the next few decades, fossil fuels will continue to be recognized as the main sources of energy supply and used to meet energy demand. One of the biggest disadvantages of fossil fuel consumption is the emission of greenhouse gases such as carbon dioxide, which raises the Earth's temperature and has devastating effects on the climate and the lives of its inhabitants. On the other hand, fossil fuels are recognized as non-renewable sources and their lifespan is only for the next few decades. Today, one of the major concerns of societies, especially in developed... 

By entering the concepts of transactive energy systems, microgrids and peer-to-peer networks into the local energy market, it has made it possible to implement local energy market in the microgrids more than ever. In transactive energy systems, with the elimination of the intermediate entity, exchanges take place directly between the different parts of the system, which results in increased system flexibility and reduced system costs. In this study, by applying blockchains in local energy market and in micro-grids and transactive energy systems, a framework is proposed to implement local energy market in an energy micro-grid based on blockchain. By using blockchain features and structure,... 

Using energy storage systems has been remarkably improved the energy systems efficiency and reliability indicators of the system and also reduced the operating costs of these systems. Thus using them in an energy system would count as an advantage. Lately, the procedure of implementation of these systems has been studied widely and various motives behind implementing them have been reviewed. For example, the effect of cost optimization in electrical vehicles on reliability indicators from the load management perspective can be addressed. Therefore this thesis has studied the effect of electrical and thermal storage systems on the reliability indicators of an energy hub and the effect of... 

An aerial structure can be at the disposal of the owners of damage or intellectual property during its lifetime, under the supervision of static and dynamic loads and providing information in the field of recognizing temperature, humidity and environmental pressure with high-speed gradient. Capable Composite patches are used to repair damaged areas. Composite patches have unique properties such as high strength to weight ratio and corrosion resistance. In structures modified with a composite patch, various failures occur during loading, including: fiber breakage, matrix fracture, separation of fibers from the matrix or the latest patch from the main structure and failure of the metal... 

In the current era, the urgent need to reduce the use of fossil fuels and limit carbon emissions has highlighted the importance of shifting from traditional gasoline-powered vehicles to electric vehicles. The evolving landscape and challenges in the field of electric vehicles highlight the importance of ensuring the safety and reliability of energy storage systems. Lithium-ion batteries play a central role in electric vehicle technology, requiring thorough research efforts. Notably, the detection of internal short circuit, a common issue in lithium-ion batteries, has become a focus of researchers in recent years. This study aims to investigate the internal short circuit fault in lithium-ion... 

Today, hybrid electric vehicles are known as one of the approaches with high potential to reduce and control emissions and fossil fuel consumption in the transportation sector, so that it can be a bridge between conventional vehicles and fully electric vehicles. One of the main weaknesses and obstacles to the widespread use of these vehicles is the habit of drivers and the lack of full evolution of the technology in the battery and its management. The one of solutions to overcome this problem is structural optimization and identification of factors effecting battery health and design of energy management system considering battery health. In this thesis, an energy management system has been...