Sharif Digital Repository

Today usage of microwave integrated circuits in commercial and military applications is very common, especially with emerging of monolithic microwave integrated circuits that make mass production with good quality and price possible. A lot of attention are paid to designing power amplifiers used in the end of transmitter line. Because of power dispersion in transistor channels, high power amplifier causes excessive heat on the chip. Channel temperature increasing, causes operation retrogradation in circuits that result in destruction of the chip. So it is necessary to transfer this heat to the outside from the chip. It is usual to use a heatsink for this problem, however for low thermal... 

In this paper, carbon structures such as multi wall carbon nano tubes, graphene and hybrid graphene-iron oxide, for utilisation in wet cooling towers in order to improve heat transfer are being discussed. All synthesized nanoparticles are prepared by chemical vapour deposition and wet chemical methods. Nature and structure of the created particles is also being examined by using X-Ray diffraction, transmission electron microscope and scanning electron microscope. The water used in this research is a kind of brine water, currently being used in industrial cooling towers at oil-rich regions of southern Iran. Performing the ICP test on the available water and by exact determination of its... 

In this thesis selection criteria are present for types, numbers and locations of sensors for structural health monitoring of offshore jacket platform in the Persian Gulf. The selection criteria are chosen by studying structural health monitoring of various structures in civil and aerospace industries. Knowing the types of sensors that can be used, a new approach of inverse vibration problem is introduced for structural health monitoring of offshore jacket platforms. In the previous studies, significant numbers of frequencies and mode shapes are usually used to detect damages by updating components of stiffness matrix. Considering the fact that offshore platforms are composed of a heavy... 

A great rise in the number of projects undertaken simultaneously within organizations and consequently, a further increase in the complexity of managing them, has led to emerging innovative forms of organizational structures. There are new concepts developing in project management literature such as program management, portfolio management and project management offices (PMOs). PMOs have recently been used as a means for managing large projects, based on the need for an overall, coherent approach. Project offices are established to coordinate portfolios of projects and achieve project management oversight, control and support. Based on the structure and definition proposed by Hill (2004), it... 

Surface phenomena and dynamic Interfacial properties play an important roles in gas- liquid and liquid-liquid multiphase process from various industrial applications to understand fundamental phenomena. However, there is no experimental equipment and efficient methods for quantitative and detail investigation of interfacial properties under fast and non-equilibrium dynamic condition due to mobility and refreshing of interface (such as rising bubble). Also existing models accompanied with a lot of simplifications which is not yet validated with a proper experimental data. development of laboratory equipment base on measuring momentary capillary pressure and presenting a new experimental... 

In this research ,lean and agile indexes in S.G.S Co. are evaluated. This company is the first company in engineering and supplying automotive parts as well as the first supply chain management and organization of Saipa Group. In the part of evaluating the lean management level it is the developed model of the suggested approach by Jackson “implementing a lean management system” (Jackson, 1996). As S.G.S is engaged in servicing activities not in production, we have changed some factors in Jackson's methodology. Different with the last model, we got the results and used AHP method for getting the level in each key. Finally by using another AHP the lean index of the S.G.S Co. was identified.... 

In this project, we are willing to analyze and design a subsonic wind tunnel WT configuration for the Aerospace Engineering Department in Sharif University of Technology. This WT will be an open-circuit "suck down" type, whose entry is open to the atmosphere (laboratory) and three axial fans downstream of its test section. In addition to three parallel fans, we are expected to design two simultaneous small and large size test sections for it. The small and large sections would have an area about 1.4 and 4 m2and maintain a maximum air velocity of 100 and 50 m/s, respectively. So, our design is faced with two main complexities. In one hand, we are to manage the air flow through these two test... 

During the recent past, due to the increase of electrical energy demand and governmental resources constraints in producing additional capacity in generation, transmission and distribution, privatization and restructuring in electrical industry has been considered. In most of the countries, different parts of electrical industry like generation, transmission and distribution have been separated in order to create competition. Considering these changes, environmental issues, energy growth, investment of private equity in energy generation units and difficulties of transmission lines expansion, DG units have been used in power systems. Moreover, reduction in need of transmission and... 

Excessive usage of fossil fuels and emissions of GreenHouse Gases (GHG) have led to many environmental problems such as climate change. The carbon dioxide emission accounts for 82% of GHG emissions and has the highest retention time in the atmosphere. The study on carbon dioxide is an important issue recently. The carbon dioxide emission from the energy and industrial sectors are 30% and 21%, respectively. It is possible to capture carbon dioxide from the flue gas may be utilized as material and fuel. Developing the utilization of carbon dioxide to replace storage is a solution for implementing carbon capture. The carbon planning model, is based on the selection of technology that is... 

The unique ability of additive manufacturing in manufacturing industrial parts with complex geometries has led to the development of topology optimization methods and their use for the optimal design of parts in various industries. However, considering the limitations of additive manufacturing methods in the optimal design of parts is usually a difficult process, and when making decisions, facing multiple conflicting design goals is often difficult and usually involves high computational cost. The main goal of this research is to provide a topology optimization method for generative design for additive manufacturing based on the concept of constructive solid geometry and using machine...