Sharif Digital Repository

Nowadays, we know that many hydrocarbon reservoirs are fractured regarding this, the investigation of the properties of these reservoirs is necessary to predict the storage, production and the drilling methods. To identify fractured reservoirs, the fracture properties and their geometries under different conditions should be investigated. Besides, the evaluation of the behavior of induced fractures in distinct under ground conditions is very important. The Mechanical properties of the drilling bed like crack propagation, layer and mass rock is impactful in planning of drilling process and hydraulic fracturing operation. In this research, at first we introduce natural and induced fractures... 

As producing and consuming of natural gas has increased in recent years, improving natural gas distribution and transfer network systems has become vital. Pressure reduction station (PRS) is an important part of the natural gas network. Common PRSs are facing two issues: first is the pressure reduction technology, which is throttling valve that destroys the exergy of the high pressure flow. The solution is to utilize turbo-expander instead which can recover the energy. Second is the preheating technology which is boiler and water bath heater in the common systems that cause environmental problems. Using solar collectors is one of the best solution based on the literature. Since the solar... 

Globally energy system is the main source of green house gas emission. 60-90 percent of manmade CO2 is due to energy sector. Pollutants like NOx, CO, Non Methane Hydrocarbons which may cause indirect effect on climate system are mainly emitting from energy sector. Gas, Oil and Coal extraction and transmission are responsible for more than 15% of Methane emission globally. Therefore it is important to consider all types of GHGs emission as well as all sectors of energy system to assess the GHGs mitigation potential throughout the energy system. Considering the significance of energy sector in GHGs emission, in this study we developed an optimized model for Iran’s energy sector in which we ran... 

Today, with the expansion of the use of renewable energy and the increase in the production of electrical products, which has resulted in the increase of active consumers in the electricity market, making an optimal decision about the production and consumption of electrical energy has become particularly important. This research examines a sequential decision-making problem in an environment with high uncertainties in which an active household consumer and a renewable producer are simultaneously present in the electricity market. The main goal of this research is to provide an optimal model for making decisions regarding the consumption and production of electric power in the power market... 

The image-based profile is a technology by which image morphology information is transformed into a multidimensional profile from a set of image-derived features. These profiles can be used to extract biologically meaningful biological information. For example, in the drug discovery process, the mechanism of action of a drug or disease can be identified by examining the morphological properties of the drug in the patient’s cell or tissue and used to design new drugs or use existing drugs for various diseases. High-throughput imaging technology allows the imaging of a large number of different experiments. Extracting valuable features and a good representation of features is the main... 

The notable share of housing sector in GDP (approximately five percent) shows this sector’s relation with macroeconomic activities. On the other hand, House as an asset leads housing sector to be affected by monetary and fiscal variables. A dynamic panel data was used in this study to evaluate the relations between housing sector and some macroeconomic variables in metropolises of Iran. As results show, in long term growth of liquidity, GDP per capita and sharp ratio have positive effects, and land per capita has negative effect on housing price in metropolises of Iran. Price increases have not been equal in different cities. Inequality of land price between metropolises and between... 

In this research, an Index of Iran informal economy in response to the government interventions in credit, labor and product markets is stimated by EMIMIC model. To do this, first these interventions are measured using principal components analysis. In the model, the variables GDP and employment are used as indicators and taxation rates, government distortions in credit, labor and product markets, government expenditure, per capita income, unemployment and inflation as causes of the informal economy. We conclude these government interventions have affected Iran informal economy and their influence is more than indirect interventions influence such as taxation. The estimated index of Iran... 

With altering natural state and increasing impervious surfaces, traditional urbanization leads to deteriorating the environment and water catchments. During the years most efforts in order to control the urban runoff outflow, have been focused on quantity; and awareness about improving water quality has been raised just in the last few years and, which emphasizes on pollution source control. Standard water quality sampling methods are time consuming, expensive and because of sampling in broad geographic areas, difficult; however modeling is a more efficient way in assessing water quality and as worries about non-point source pollution grows, different kinds of models have been used to... 

The role of government in economy has been a controversial subject in economics. Lately, there has been some fundamental change in evaluating this subject. One could mention two of these as 1) realizing the importance of micro-founded macro model for evaluating policy, and 2) taking into consideration the rent-seeking behavior of politicians. In this research, a general equilibrium in a micro-founded macro model will be discussed and then in political economics framework, the effect of government on this equilibrium will be investigated. Only the redistribution role of government has been considered. First, the model in which a benevolent government is seeking optimal policy is Discussed.... 

Gini coefficient is the most prevalent index for the measurement of inequality and is usually extracted by means of nominal variables based on income or expenditures of households. In this study we have extracted more accurate Gini coefficients. By using the raw data of Households Budget Survey (HBS) and STATA software, a special CPI for each household of the sample is extracted. Subsequently nominal expenditures are deflated by these special CPIs, and at last, Gini coefficients are extracted from real expenditures. Our findings indicate that in recent years, extracted Gini coefficients are remarkably higher than prevailing ones.
 

This paper investigates the behavior of the Y-shaped bracing system. Because of the special type of eccentricity in this system, the behavior of the frame is strongly dependent on the geometrical changes of the braces. So that even in the elastic region, it shows the geometrically nonlinear behavior. The amount of eccentricity is very effective on the nonlinear behavior of the frame. Also the ratio of cross sections of the bracing members has a very important impact on the expected performance of the frame. The results show that this system tolerates large displacements, and can act like a base isolation system. Firstly, using a two-dimensional accurate modeling related to the geometrical... 

The Overstrength, Ductility and the Response Modification Factor (R) for 70 steel X-braced , Inverted-V-Braced and Offcenter Bracing System frames were evaluated by performing pushover analysis of model structure with various stories (3,6,9,12&15 story) and span length (4,6&8 meter). Some result were compared with those from nonlinear dynamic analysis. According to the analysis result the R factors obtained from nonlinear dynamic analysis are 15% more than obtained from pushover analysis and R factors computed from pushover analysis were generally smaller than the values given in the design codes. R factors in Irregular structure in height are about 90% of R values in regular structure in... 

Maghemite (γ-Fe2O3) nanoparticles were produced after high temperature oxidation of gelatin-Fe3O4 nanocomposite, obtained from a common coprecipitation process of Fe2+ and Fe3+ ions in an alkaline medium in the presence of a gelatin protein as an effective mediator. Size, shape, surface morphology and magnetic properties of the prepared γ-Fe2O3 nanoparticles were characterized using XRD, FTIR, TEM, SEM and VSM data. The results revealed that primary, gelatin-Fe3O4 nanocomposite had been formed and next, the gelatin decomposition in furnace produced a spinel structure of γ-Fe2O3. The effects of furnace temperature and time of heating together with the amount of gelatin on the produced... 

The Response modification factor R represents the behavior of the structure such as ductility, overstrength and the inherent redundancy. This factor shall be defined according to the type of lateral force resisting system. However, there are some complexities and/or uncertainties in codes related to the R factor according to the height, form of irregularities and structural systems. Therefore, from the scientific point of view as well as reliability, it is very clear that the R factor cannot be similar for all kinds of structures, categorized as a specific group. In this investigation, assuming a low-rise, vertically irregular structure with a heliport which has a dual structural system... 

Maintaining the quality of water is of paramount importance for lakes with tourist attraction capacity. Inaccurate prediction of the quality state of lake in design phase may lead to some trouble in future. Kan River known as the main source of water feeding for the urban lake located in the north of Chitgar park passes through various villages and restaurants discharging nutrients via runoff and wastewater in the aforementioned river. Previous investigations reveal that phosphorous plays a central role in the water quality of this river and the associated downstream lake. In this research, Kan watershed,located in in the north-west of Tehran, was simulated. Considering the "Total Maximum... 

Findings of economics in last decade shows that social and economic institutions have direct influence on economic performance of a society. However, these institutions are determined by the state. In different regimes, the political power is in the hand of different social groups with different preferences and goals; as a result, different social and economic policies and institutions are take place in different political regimes. In this research, we study economic performance of a society under control of two different political regimes: in first, the majority rules the state and in second, there is a totalitarian regime in which; the political power is concentrated in hand of a group of... 

Economic performance of resource rich countries is related to their political systems. In this research, consistent to Hosseini (1388), we develop a theoretical model in which we classify the political systems of those countries to four systems based on corruption, myopic behavior of the incumbent, ideological bias of people, and the popularity shocks in elections. We show that in a fixed institutional framework, democracy leads to higher welfare for people and better economic performance. However, in a society with low corruption, high political convergence, and low popularity shocks both democracy and dictatorship maximize the social welfare in the model