Sharif Digital Repository

Centrifugal microfluidic systems due to their unique properties, including the ease of sample transfer, high controllability, the need for samples and reagents in a small volume scale, the possibility of embedding a complete laboratory and modeling a variety of processes on a disk, they have great potential to be used in the field of point of care diagnosis. Such devices can perform several different processes simultaneously and continuously by using inertial and pneumatic forces as well as a complex network of microchannels. The purpose of this research is to design and build a centrifugal microfluidic disc for lysing amniotic stem cells, followed by DNA extraction, in order to detect fetal... 

Process of casting with evaporative patterns and unbonded sand is a new method that due to different economic, environmental and technological benefits is considered to large and small industrial parts manufacturing in recent years. Different parameters are effective on the surface and metallurgical quality in this process, such as foam density, sand type and size, level and mode of vibration, sand compaction, coating and pouring time and temperature. If coating permeability that is function of type, thickness and concentration of coating is chosen improper, pyrolysis vapor of foam don’t exit completely and in this condition carbon of vapor deposit on the metal surface and produces defect... 

Acidizing is a widely used well stimulation technique designed to mitigate formation damage and enhance oil and gas production. The effectiveness of acidizing operations relies on meticulous design. Consequently, before implementation, it is essential to create an optimal operational plan using suitable laboratory tools and numerical methods to maximize efficiency. Numerous studies have been conducted to investigate and model wormhole propagation in carbonate rocks, including commonly used two-scale continuum models. Although these models effectively predict physical behavior, the numerous parameters involved complicate history matching with laboratory results, potentially leading to... 

Three dimensional analyses have been carried out for predicting the behavior of the jointed rock slope of the abutments of the bridge which is proposed to be constructed across the river Karun4 in Iran using 3DEC. The rock sloping at 500 to 600 are composed of highly jointed rock mass and the joint spacing and orientation are varying at different locations. Since 3DEC is a three-dimensional numerical code, utilizes a Lagrangian calculation scheme to model large movements and deformations of a blocky system, allows for modeling of large movements and rotations, including complete detachment of rigid or deformable discrete blocks has been utilized for the analysis. The analysis has been... 

Considering high potential of solar energy and exhaustibility of fossil fuels in Iran, using solar energy seems to be inevitable. But one of the main problems in the application of these systems is high investment and maintenance costs. So, in this thesis, suitable solution is presented for decreasing cost and optimizing of a solar absorption refrigerator based on developed energy model. This system consists of two CPC solar collectors and a thermal energy storage system using phase change materials that provides input energy to the generator of absorption refrigerator. The exergy efficiency of system components is calculated by relations of energy model and exergy analysis. Then... 

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  

This research considers the wind effects on the thermal deficiency of natural draught dry cooling tower (NDDCT) using the CFD tool. To have a realistic study, the NDDCT of Shazand Powerplant, located in Shazand, Iran, is simulated as the sample cooling tower design points. Considering of Shazand NDDCT model, the mal-effects of local wind were studied against its thermal efficiency. As is known, the thermal efficiency of a NDDCT can be affected by local wind in either its upper (i.e., outlet section) or lower (i.e., the radiator section) parts. In this study, a full study is performed to quantify the mal-effects of local wind on either upper or lower parts of one tower. The results show that... 

Many efforts have been performed on the poly(vinylidene fluoride), PVDF, due to its piezoelectric, pyroelectric and ferroelectric potentials. In this thesis Poly (vinyldene Flouride) (PVDF)/Poly (vinyl Asetate) (PVAc)/Multi-walled carbon nanotubes (MWCNT) and Poly (vinyldene Flouride) (PVDF)/Poly (vinyl Asetate) (PVAc)/Graphene Oxide nonasheets (GOn) nanocomposite films were prepared via solution casting method. The effect of concentration of PVAc, MWCNT and graphene oxide on PVDF nanocomposites were investigated. Graphene oxides synthesized by modified Hummer’s method. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results showed that the crystalline structure of...