Sharif Digital Repository

Rapid growing use of energy resources in recent decades, caused to focus on combined heat and power generation systems according to their high efficiencies. Energy efficiencies with these technologies will be up to 90 percent. Some benefits of Co-generation systems are their high efficiencies, omitting of transmission and distribution lossesin the electricity grid, fuel consumption reduction, moving to ward privatization,independent and decentralized production of electricity and heat, increase competition in the power generation and reduction theemission of greenhouse gases, particularly carbon dioxide. In This article theeconomicsof combined heat and power generator stobe installed... 

In this research, the feasibility of the usage of the Wells turbine for direct conversion of the hydro-mechanical energy of the surface waves is studied via analytical and numerical methodologies. The results produced, showed for the first time that the Wells turbine can be employed for such waves directly and the performance variables are quite reasonable and even efficient considering low cost of HKWT system and abundant availability of those waves. For the low-frequency waves, the turbine is tested for different wave velocities to discover the best angular velocity of the rotor in terms of performance and the rotational velocity of 300 RPM has been found to be the optimum amount. Further,... 

Damage detection in all kinds of human-made structures has been given serious attention as one of the main branches of engineering sciences, and significant progress has been made in this field, especially in the field of civil engineering, aerospace and heavy industries. However, although this topic is discussed academically in the field of offshore structures for two decades, not much development has happened in practice and it is still in the stage of knowledge development. One of the most important characteristics of practical online damage detection methods is the ability to be used knowing little information about the modal characteristics of the structure. In this research, an attempt... 

The ultimate aim of this research is optimizing high- performance Horizontal Axis Wind Turbine (HAWT) associated with using Computational fluid dynamics (CFD) to predict the flow behavior over wind turbine blades. Computational prediction of the flow over wind turbines is a challenging numerical problem because of the complicated aerodynamics and large variation in length scales. Phenomena such as; the unsteady flow, vortex shedding of the blade tips, flow separation, complicated blade geometry due to variable twist and chord and changes in angle of attack, and highly turbulent flow over blade sections makes CFD prediction challenging, as well as interesting. The goal is to gain an in depth... 

The use of clean energy sources has become increasingly popular around the world in recent years. One of the most important of these sources is wind energy. Due to the high wind potential in offshore areas than on land, this study uses the integration of multi-criteria decision-making methods and GIS to identify the best areas for developing offshore wind farms in the Persian Gulf and the Sea of Oman. Criteria applied in this study are divided into two categories: restrictive criteria, such as recommended transportation routes and anchored restricted areas, and technical criteria, such as wind speed and water depth. After removing the inappropriate areas using restrictive criteria, the... 

Recent studies have shown that almost 40% of the world's population faces a water crisis, and this amount will reach about 60% by 2025. Due to limited freshwater resources and the increasing world population, we have to use seawater desalination systems to supply water to this growing population. One of the outputs of desalination plants in addition to freshwater is saline effluent or brine water, which is the most important environmental impact of these plants. In this study, an attempt has been made to investigate the various factors affecting the discharge and release of saline effluent from desalination plants and observe its impact on the ecosystem and marine environment. In this... 

One of the biggest problems in improving the performance of submersible propellers is the acoustic standard in conventional propellers. Recently, new solutions in propellers geometry have been used to reduce non-cavitation noise. Designing CRP licenses is one of these methods. This research includes numerical analysis. Numerical analysis in this research solves RANS equations of flow and extraction of hydrodynamic parameters and impeller noise in Ansys software. The results of numerical hydrodynamic solution are validated by laboratory results.DTMB 4119 three-blade propeller is used for hydrodynamic and hydroacoustic validation. The solution of Lighthill equations by FW-H method is... 

Today, as an effective tool for marine applications, towed submarines play an im-portant role in various sectors of the marine industry, including defense, recreation, ocean exploration, etc. The high cost of existing thrust systems, as well as the signifi-cant vibrations in them, run counter to the goal of designing this small, low-cost sub-marine. Therefore, the decision was made to design this vessel with a tensile thrust system. In this project, an attempt is made to introduce and design the structure of the body and the carrying capacity of the passenger by a recreational submarine with the ability to move 10 people as passengers And while introducing the structure of the body shape and... 

The sea's ecosystem is the most sensitive and essential as the last recipient of sea and land pollution. The increasing requirement for building thermal power plants and desalination plants and a great demand for their thermal effluents discharge causes a serious threat to the rich coastal environment. In this project, a general study on environmental and meteorological data required to investigate the environmental effects of effluent discharge from desalination plants in the Persian Gulf and the Sea of Oman has been conducted, and the general process of conducting thermal effluent discharge research in this area is presented. Next, in a case study using MIKE hydrodynamic software and... 

Business Activity Monitoring (BAM) is a method for evaluating current condition of organization from the viewpoint of reaching to its strategic objectives and helps man-agerstobe informed straight forwardly about thecurren tstatu sofeach Key Performance Indicator (KPI). Enterprise Service Bus (ESB) is an infrastructure for transferring web services between some software components that performs in Service Oriented Archi-tecture (SOA) domain and its goal is improving interoperability between components.As BAM needs to interact with other systems to receive event flow and ESB assists this interaction, there is a need to define a general framework to establish communication between them and... 

There is a plethora of research and implementations that intend to increase the performance and reduce implementation costs of network routers. In this work, we review previous designs and propose a new network router design that is based on software-defined networks. Our design separates the data plane and the control plane from each other and connects both parts by using OpenFlow protocol. The control plane consists of a general small computer that utilizes the Quagga software to enforce the routing protocols. The control plane translates routing decisions to OpenFlow instructions and sends them to the data plane. The data plane is based on a switch that supports the OpenFlow protocol... 

Regarding the reduction of high qualified and accessible resources, the waste water treatments are accounted as one of the main challenges in environmental context. Surprisingly, with or without consideration of this issue can lead to play the crucial key in whether development or society retardation. With developing and being more sophisticated of waste water treatment technology and also rising the stringency of environmental constraint, approaching the optimum technology basis economics of scale is time consuming and complicated.Behind this concept, contribution of this study is twofold. The general approach of treatment is identified using AHP methodology in primary stage. After that, it... 

In this paper we answer to the following questions: First, whether we obseve conditional convergance indicating that the poor Iranian provinces tend to grow faster than the rich ones? Second, has inter-provinces migration helped the convergence? Three different indices are used for examining inter-province convergance. These include: per capita expenditure and per capita income both from the household survey since 1364 to 1394 and per capita regional GDP since 1379 to 1393. Our results support the convergance phenomena based on all three different indices. For the second question, we use instrumental variable to resolve the potential endogeneity problem caused by the reversed causality... 

Fusion welding of Duplex Stainless Steel (DSS) and dissimilar welding of This alloy and other steels have a lot of problems such as losing phase balance and formation of secondary phases i.e. Sigma Phase. Therefore, Friction Stir Welding (FSW) was used as a substitute for traditional fusion welding techniques of DSS. The present study investigates the relationship between the process variables and microstructural and the mechanical properties of frictional welding of similar and dissimiliar FSW of DSS to carbon steel in order to obtain the joint with the highest mechanical strength. In this study, similar welding of S2304 DSSs and dissimilar welding of S2304 and St12 using FSW were...