Sharif Digital Repository

In this investigation the thermodynamic, economic and environmental analysis of a 4rth generation system for simultaneous produce of heat, power, water and cooling of a residential building in Tehran-Iran has been done. Four different system have been used for power generation: 1-combined cycle of Direct Internal Reforming Solid Oxide Fuel Cell and Gas Turbine (IRSOFC-GT) 2-combined cycle of Gas Turbine and Steam Turbine (GT-ST) 3- cycle of Gas Turbine with Recuperator (GT-R) 4- cycle of Steam Turbine (ST). A double effect absorption chiller has utilized to provide the cooling load of the building, while a heat exchanger provides its thermal requirement. Also a MED-TVC system was used to... 

In recent years, ground source heat pumps (GSHPs) have received increasing attention for space heating and cooling, and domestic hot water production due to their high energy performance and low environmental impacts. The most common type of ground heat exchanger used in the GSHP systems is borehole heat exchanger (BHE) that consists of U-shaped tubes placed in the vertical boreholes. In this system, the heat is absorbed from or rejected to the ground by circulation of a fluid through the ground loop. The GSHP systems provide high seasonal performance factors when the ground loads are well balanced over the year. However, most buildings in cold or hot climates have unbalanced loads. When the... 

Increasingenergy requirements, limitedfossil resources, environmental pollutioncaused byfossilfuels, global warmingand other factorshaveled tothe approach ofscience and technologyfor renewable energies. One of the renewable energies is the energy relevant to ocean currents that is mainlydue to theinteractionbetween thetidalattraction ofthe moon,sun andearth. In our country,due tothehigh tideon the southern coast, there isgood potentialto use thistype of energy. One of themost favorableareasformarinecurrentpower plantslocated inthe northern part ofthe islandof Qeshmchannel.In this thesis,to exploitthis potential, the newidea ofHunter tidalturbine was investigated,because... 

In recent years, providing sustainable water supplies in dry and low water areas in the south of country is one of the important problems in the country. In addition to advantages of using cogeneration systems (power plant and desalination unit), using hybrid technologies causes productivity and reduction in energy consumption and water supplies. The target of this thesis is studying different thermal coupling scenarios to find optimum and constraint design in specific conditions in terms of cost and production. So in this conceptual study, by using thermoflow software, the hybrid unit coupled with a back pressure and condensing combined cycle power plant was studied based on thermodynamic... 

In recent years, requirement engineering and goal modeling have gained more attention among different organisations. Therefore, different methods have been designed to discover stakeholders’ requirements and translate them into process and organizational goals. Various goal models have been introduced to represent these goals and their relations towards each other. Still, these methods are manual representations of different process scenarios and do not relate to the actual behavior. In 2014, Map Miner Method (MMM) was introduced to discover intentional process models from event logs. MMM uses Hidden Markov Model (HMM) as a means to represent the process as a map model of strategies and... 

Recommending routes to city taxis in order to improve their performance in finding passengers can reduce traffic, pollution and waiting time for passengers, as well as this, increasing the efficiency of taxis can increase their income. In this study, by analyzing trajectory data obtained from 536 taxis in San Francisco over a period of one month, we generated networks of cells, each of which has time-dependent characteristics such as the probability of finding a passenger, the capacity of each cell, or the amount of demand exists is in the cell and the average speed of passing through that cell. also, the connections between these cells in order to make more use of the experiences of taxi... 

The purpose of the present study is to develop neural network estimation method for hybrid or panel data which have a combination of two cross-sectional and time series structures and because of the features of both structures, their use in different sciences offers many advantages; and the analytical methods for this data structure are also different from other one-dimensional structures, so different and specific regression models are presented for this data structure. However, in the artificial neural network method, modeling the development for this data structure is neglected, so in the present study, using the concepts of panel regression methods and their application to the... 

The potential of phase change process in liquids at microscale has been a favorite for the scientists to fabricate this type of micropumps. To hold unidirectional flow in microchannels usually nozzle-diffuser arrangement is used. Due to the existence of difference in pressure drop in the nozzle and diffuser sections, one can see unidirectional flow through diffuser direction. The objective of this article is to analyze analytically the thermo-hydrodynamic behavior of the Isopropyl Alcohol (IPA) bubble of a phase change micropump. Considering the simultaneous effects of hydrodynamic and thermal characteristics of the bubble in the bubble generation chamber, and temperature-saturation... 

Porous burner technology has many advantages in comparison with conventional burners such as higher burner thermal performance, lower pollutants emission, high power ranges, fuel flexibility, compact geometry and higher turn down ratios. These kinds of burners are made of preheated porous combustion zone and combustion porous zone that have different thermophysical and geometrical properties. In this work, the transient one-dimensional multi-step premixed laminar reacting flows in a two-stage porous media burner have been investigated. The combustible mixture is considered H2-Air (9 species and 19 reactions) and CH4-Air (22 species and 49 reactions). In porous media, without lateral wall... 

In this research we investigate the effect of demand disruption on coordinating a supply chain with one manufacturer and one retailer competing with a manufacturer. For this purpose we consider two kinds of demand function: 1) a demand function which determines the demand deterministically and 2) a demand function with a random factor which determines the demand stochastically. Also we assume that in competition between retailer and competing manufacturer, retailer possesses more power than his rival in the market. In order to study the effect of demand disruption on coordinating the supply chain, first we consider coordination without demand disruption by using linear quantity discount and... 

Hydrocyclones are used for separating different materials from liquids in a variety of applications. Compactness, efficiency, reliability and low maintenance costs are their noteworthy characteristics. Dewatering and deoiling hydrocyclones used for refining crude oil or oily waste water in offshore platforms are examples of liquid-liquid hydrocyclones. Separation process in hydrocyclones is based on the fact that swirl flow induces a centrifugal force and leads to separation due to density difference. The density difference in liquid-liquid mixtures is smaller than solid-liquid types and trying to separate one liquid from another takes much more effort than the other type. Increase of... 

Integration of radio transceivers results in developing low power low cost wireless systems and allows delivery of multimedia contents to battery-powered mobile terminals. Portable reception of digital video for hand-held devices is one of the applications, for which, some telecommunications standards have been developed in the recent years. This research deals with the integrated implementation of the radio frequency parts of the digital video receiver, especially the frequency synthesizer. The key aspects of the digital video reception system are the required signal to noise ratio, which is relatively high, wide band input signals and strong interferers in the receiving band.
In... 

Energy conversion and storage as well as life sciences are among the areas of our daily life. Interest in carbon nanomaterials for energy storage systems such as supercapacitors has enormously risen due to their attractive electrical conductivity, chemical inertness, and charge storage capacity. Producing these nanomaterials with a simple, scalable, and cost-effective method is the major problem for commercializing them. The reduction of graphitic oxide is a versatile procedure to prepare 3D graphene. Despite many green methods, the dynamics behind ultrafast thermal graphitization have remained elusive. Here, we demonstrate an effort to understand the graphitization mechanism of graphitic... 

Influence tactics are methods which people use to influence others. These tactics may have different effect due to their sources of power, context, etc. On the other hand, if others perceive somebody authentic while he/she is using a tactic, it can be more effective. Through in-depth interviews with the members of the government and private sector dialogue council in Yazd’s Chamber of Commerce, this research examines the tactics of rational persuasion, appraisal and ingratiation. It seems that knowing the person who is arguing, the validity of his argument, emotionalizing the meeting atmosphere and some side factors like body language are effective in the perception of authenticity from that... 

One of the utmost important factors during salvage operation of drowned ships is raising velocity. Uncontrolled raise is a dynamic phenomenon which can lead to the sudden tensions, collapse in airbags or ships. Studing this issue helps the engineers which kinds of problems are more important during salvage operations. This study focus on modeling and analysis of raising movment of the ship with FLOW-3D and ABAQUS software.
In FLOW-3D environment, hydrodynamic analysis of rising movment of drowned ship has been done. We should mention that applied forces and velocities and other parameters from the FLOW-3D output should be passed IMCA Criteria to avoid uncontrollable raise. In ABAQUS... 

Profile Monitoring is a new research topics in the field of statistical process control. In many applications of statistical quality control, sometimes quality of a process or product described by a relationship between a response variable and one or more independent variables.The researchers call this relationship profile. The study seeks to demonstrate that monitoring profiles In addition, the industry can be effective in medical field and improves control of the patient's condition by a doctor. Profiles are usually modeled with a linear regression equation, non-linear or polynomial. finally, the results of this study, using actual data, models and methods to predict and control...