Sharif Digital Repository

In This work, the performance of a finite volume (FV) numerical method is examined for simulating naturally fractured hydrocarbon reservoir. The dual-porosity approach applied for fracture modeling, and the flow transfer formulated based on a generalized black oil model which is based on matrix formulation, leading to a system of equations prone to degeneracy. This FV high-resolution central scheme numerical method is not sensitive to the choice of CFL number like some of other central schemes and can conveniently handle degenerate equations appearing in the reservoir simulation governing equation. In this effort, one dimension multi phase flow simulated in naturally fractured reservoir and... 

The use of Radio Frequency Identification is increasing rapidly. The reason is the capability to transfer data wirelessly without line-of-sight necessity, high data rate and long read range. The main advantage of barcode is its lower cost which has ensured its existence for many years. The applications and materials that are identified by RFID increase as the price of RFID tags decrease. This Project deals with the front-end of an Integrated RFID Reader for the UHF band. The bottleneck of the design is the presence of a large interferer just hundreds of kilohertz apart from the desired signal which is at about 900 MHz. The key idea of the design is utilizing feedback in order to cancel... 

Smoothed Particle Hydrodynamics (SPH) is a Lagrangian method for simulation of fluid flow. Movable particles are used to interpolate fluid properties instead of fixed Eulerian grids in this method. By essence, the aforesaid particles are movable points which carry the fluid properties such as temperature, enthalpy, density, etc. these variables can also be the stress, strain or the rheological properties of the fluid. Thus, this method needs no grids and the fluid properties are calculated using an interpolation mechanism which classifies this method as meshless. A computational code is designed using SPH for the simulation of multiphase flows. Usage of the Lagrangian formulation has made it... 

Since coronary artery diseases are increasing every day, simulation of blood flow in blood vessels and their stenosis is one of the most important topics nowadays. Many efforts have been made to achieve numerical simulations using different methods such as Finite-Difference. In this thesis, an SPH method is used to simulate pulsatile blood flow in arteries. The weakly compressible algorithm consists of two steps of prediction and correction. In the prediction step, the velocity field is integrated forward in time without enforcing incompressibility. The correction step consists of enforcing incompressibility by solving the pressure Poisson equation which creates a trade-off between the... 

If the reservoir temperature lies between the critical temperature and cricondentherm of the reservoir fluid, the reservoir is classified as a retrograde gas-condensate reservoir. When the pressure is decreased on these mixtures, instead of expanding or vaporizing as might be expected, they vaporize instead of condensing. If the reservoir pressure is above the upper dew-point pressure, the hydrocarbon system exists as a single phase in the reservoir (region 3). As the reservoir pressure declines isothermally during production from the initial pressure to the upper dew-point pressure, the attraction between the molecules of the light and heavy components move further apart. As this occurs,... 

The removal of glyphosate, one of the most widely used herbicide, with membrane bioreactor (MBR) was studied. Beside of glyphosate, the synthetic wastewater contained molasses and other salts as nutrient source. The membrane was made from polypropylene and was immersed in the bioreactor. The COD of the feed was adjusted by varying the ratio of glyphosate to molasses. The total COD was 500, 750 and 1000 mg/L. The resulted showed that when the bioreactor coupled with membrane the removal efficiency increased. The increase was attributed to higher concentration of biomass or MLSS in the MBR. The average of MLSS in the MBR was 8500 mg/L while in bioreactor without cell recycling and in batch... 

Part 1
1,3-dipolar cycloaddition reactions offer convenient routes for the construction of a variety of five-membered heterocycles. This thesis represents a simple synthetic method via 1,3-dipolar cycloaddition reaction to prepare a novel class of spiro pyrrolidines and spiro pyrrolizidines which exhibit many biological activities. Non-stabilized azomethine ylides which generated in situ by the decarboxylative condensation of ninhydrin with proline and sarcosine were used as a 1,3-dipoles. On the other hand, chalcone and its derivatives with an impressive array of pharmacological activities were the dipolarophiles in these reactions. The reactions were carried out through reflax... 

Smoothed Particle Hydrodynamics(SPH) is the oldest Lagrangian method for solving fluid equations. Fluid is approximated with particles that represent a control mass and carry physical properties su as mass, temprature and . . . Simpler formulation relative to other methods like finite volume and finite element, no need for surface traing and ease of adding new physics are benefits of this method. In this method it is necessary to find neighboring particles that are closer than smoothing lenght (h) for ea particle. is is a time consuming operation causing SPH to be a computationaly expensive method. First simulation of Power-law fluids is considered. It has been observed that using of... 

A 1.8-v 1.8-GHz fully integrated CMOS fractional-N frequency synthesizer is designed and tested for UHF RFID readers. The synthesizer employs a dual-loop architecture to realize a monolithic design with more optimal trade-off among phase noise, channel spacing, reference frequency and settling time compared to the conventional integer-N phase-locked-loop architecture. Due to the large self-interference and the backscatter scheme of the passive tags, reader synthesizer’s phase noise requirement is stringent to minimize the sensitivity degradation of the reader RX. A 1.8-GHz complementary VCO with noise filter has been used to achieve these tough specifications. Also, since a large KVCO can... 

Learning of shape classes from a set of given data is of special practical importance in computer vision. Large variations in the surrounding objects makes the problem of shape learning a very di°cult one. These di°culties may vary according to diferences in pose and part articulations of shapes. Despite all of the problems, large applications of this problem in areas such as tracking, object recognition and text recognition inspires many groups to work on it. In this thesis we aim to investigate a solution for this problem  

Commercial banks have got an important role in our lives and every one can mention veriety functions for them. The more benefits can bring the more risks can couse as the old tradeoff between risk and return. One of the important risks that can bring about lots of problem for banking system is liquidity risk. Being not able to respond customers’ liquidity demand is named the liquidity risk. Banks keep some reserve in cental bank to respond other banks’ liquidity demands in payment system. Shortage of this reserve will cause customer and central bank punishments and penalties. Excess reserve on the other hand has opportunity cost. Hence an optimum amount of liquidity resrve must be held in... 

This research has been surveyed the impact of intermediate skilled and high skilled human labor force on the productivity of manufacturing sectors by the Nelson & Phelps and also Lucas approaches. first model is related to the level of productivity and the second model is related to the growth of it. We has been prepared the needed statistics from the raw figures of iran statistics center. regression analysis has been done on the basis of panel data model by the use of stata software. the results show that not good efficiency to optimize technology factor of Cobb-Douglas model although it shows higher marginal labor productivity of high skilled human labor force. we has proposed some... 

In this thesis an SPH method is used for simulating multiphase two- and three-dimensional Newtonian fluid flows. The weakly compressible algorithm consists of two steps of prediction and correction. In the prediction step, the velocity field is integrated forward in time without enforcing incompressibility. The correction step consists of enforcing incompressibility by solving the pressure Poisson equation which creates a trade-off between the pressure and density variations. The surface tension force is applied in the linear momentum conservation equation by the divergence of the surface stress tensor. Advanced techniques are applied to achieve better convergence and reduce pressure-related... 

There is a strong drive toward handheld communication devices with building blocks that are fully integrated in standard CMOS technologies. Although there are obvious cost, size, and repeatability advantages, it is particularly challenging to implement fully integrated power amplifiers with no external matching in standard CMOS under the large supply variations and harsh load mismatches present in handheld devices. This Project deals with the front-end of an Integrated RFID Reader for the UHF band. The bottleneck of the design is the design of a fully on-chip Power Amplifier. In this thesis, a new method is introduced to increase transistors breakdown voltage in a class E power amplifier.... 

Degradation of signal to noise ratio (SNR) in today's low voltage circuits has been a challenging problem for analogue circuit designing. This problem is produced due to supply voltage reduction and noise level consistency in today's analogue circuits. Great efforts have been done in literatures for noise reduction in some analogue circuits, like low noise amplifiers, but there is no general method for noise reduction in active filters and introduction of a general method for noise reduction in active filters which are in vast usage in all analogue circuits, has always been demanded by circuit designers. In this project, a general method for noise reduction in active RC filters is introduced... 

Nowadays, due to the advancement of robotic technologies and development of industrial robots, the robot manipulators are widely used for automation of various manufacturing processes, such as finishing processes. In these applications, the contact has to be made between robot end-effector and environment. Therefore, control of interaction force in the constrained manipulators is an important demand. On the other hand, due to use of gear box and belts for energy transmission in robot joints, robot manipulators have flexible joints. The vibration, generated due to the interaction force and robot joint flexibility, can deteriorate surface roughness in automated finishing processes. In order to... 

In recent years, oil and gas reservoirs are one of the most valuable natural resources and are the main economical basis of the country. Therefore any research which can help to optimize the efficiency and enhance their recovery is of great importance. In the past 30 years, reservoir simulation has evolved from a research field to one of the most flexible tools in reservoir engineering. Simulation is usually more quick, cost effective and reliable than other methods in predicting reservoir performance. Because of complexity of the great amount of computations, research in oil reservoirs field is usually done by mathematical/computer programs, named as simulators. For this reason, various... 

One of the most important issues in the petroleum industry, is how to increase the oil production from hydrocarbon reservoirs. The optimum design of an enhanced oil recovery process needs the knowledge on the physical phenomena of the working flow in oil reservoirs. An important aspect of any oil recovery process is the effectiveness of process fluid in removing oil from the rock pores at microscopic scales, in a way that it determines the success or failure of the recovery process. Meanwhile, one of the most important factors on the fluid mobility and as a result the microscopic mobility efficiency is the pressure difference between different phases in narrow paths of porous media. This... 

Multilateral wells are relatively new alternatives in field development and because they can increase the productivity per well and reduce the cost of field development, they are rapidly replacing old methods. In order to predict the performance of well, three methods are usually used: Analytical methods which use closed-forms models, semi-analytical methods which entails line-source model and numerical methods which is based on techniques such as finite volume or finite difference. In this thesis, line-source model is extended from two dimensional forms to three dimensional forms in order to be used to optimize the path of multilateral wells. Optimization entails direct optimization...