Loading...
Search for:
porosity
0.014 seconds
Total 312 records
Fabrication and Surface Engineering of Pu-Tio2 Nanocomposites with Improved Mechanical, Surface and Hemocompatibility Properties with Usability in Vascular Tissue Engineering
, Ph.D. Dissertation Sharif University of Technology ; Baghery, Reza (Supervisor) ; Pourjavadi, Ali (Supervisor) ; Ghanbari, Hossein (Supervisor)
Abstract
The main focus of this project is the fabrication of surface engineering scaffolds based on polyurethane and titanium dioxide. The research's aim is the creation of the synergistic properties of TiO2 and PU as a new strategy for engineering artificial autologous blood vessels. In the first section, PU-TiO2 nanocomposites were synthesized by co-insitu synthesis of nanoparticles and polymer. The nanocomposite films were prepared by solvent casting and thermally induced phase separation methods. Mechanical and biological properties of films were compared with pure PU film. In solvent casting method, the outcomes revealed that the rate of endothelialization of the nanocomposite scaffold after 7...
Design and Fabrication of Thermoelastic Nitinol Implant with Radius Variation for Denture Base Replacement
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhad, Khatiboleslam (Supervisor)
Abstract
In this research to solve the problems related to titanium implants, a new type of dental implant was designed and fabricated by using shape memory and pseudoelasticity properties of porous nitinol alloys. The elastic modulus of this implant (equal to 0.8 GPa) is similar to the cancellous jaw bone (equal to 0.3-1 GPa) which causes a normal distribution of stress and prevents bone resorption. The current approach is use of radius variation to facilitate implant surgery. These radial changes are created by using one way shape memory effect. First, the implant enters the jaw cavity by decreasing the radius and after reaching the body temperature and restoring the initial shape, the radius of...
Design and Construction of a Neutron Porosity Probe and Comparison of its Experimental Measurement with MCNP Simulation Results
, M.Sc. Thesis Sharif University of Technology ; SohrabPour, Mostafa (Supervisor)
Abstract
Today the hydrocarbon materials rank in the list of requirements of the modern societies. The increased growth of the human population, their industrial economic activities, transportation etc. requires sufficient supplies of our resources. Therefore, the hydrocarbon resources need to be discovered and evaluated accurately. There are different methods that are used to measure underground hydrocarbon resources such as well logging. In this method, a measuring device is lowered into a well to evaluate several parameter of the surrounding soil. Nuclear well logging is a sub category of well logging that uses nuclear rays to do this measurement. This method has different types of sondes which...
Design and Fabrication af a Bioceramic-Polymer Composite Scaffold Using Bioprinter for Regeneration of Osteochondral Tissue
, M.Sc. Thesis Sharif University of Technology ; Mashayekhan, Shohreh (Supervisor)
Abstract
In this work, we have used a 3D printer and unidirectional ice-templating technique in conjunction, to fabricate a novel composite scaffold to facilitate local osteochondral defects tissue regeneration with a cell-free approach. Using ice-templating to induce radially-aligned porosity formation in type I bovine collagen is known to expedite host cells' migration into the scaffold which their ECM secretion shifts cellular milieu toward that of its neighboring tissue layer. We used numerical analysis to design and optimize appropriate freeze-casting mold, finding the optimum value for pin height and metal slab depth to be 4mm and 14mm, respectively. Collagen content equivalent to 2%w/v was...
Comparative Examination and Preparation of Polymeric Hydrogels in Order to use as Cellular Scaffold
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran (Supervisor) ; Sharifi Aghdas, Farzane (Supervisor) ; Mashayekhan, Shohre (Supervisor)Effects of Oxide Film on Tensile Properties of A356 Aluminium Alloys
, M.Sc. Thesis Sharif University of Technology ; Davami, Parviz (Supervisor) ; Varahram, Nasser (Supervisor)
Abstract
Since mechanical properties of cast Al-Si-Mg alloys are directly influenced by microstructural defects, understanding the characteristics of these defects and any interaction between them is important for improving the properties of castings. This study investigated the effect of the most common defects normally found in cast aluminium alloys namely, double oxide films, Fe-rich phases and prosity. A different level of each defect was introduced into castings to investigate their effects on tensile properties of A356 Alloy. Differents casting condition experiment produced different entrained oxide film, Fe-rich phases and porosity caused by shrinkage content, from low to high, were tested...
The Effect of Porosity on Photocatalytic Properties of TiO2 Nanocoating Fabricated By Sol-Gel
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
This thesis is concerned with the synthesis and characterization of high porous Ti based on thin films and the effect of polymer agents on their photocatalytic properties. Ti films can demonstrate different properties like self -cleaning and treatment of broad range of aqueous pollutants when it is exposed to light of wavelength less than 400 nm. This is due to photocatalytic reaction occurring on film surface which results in film superhydrophilicity and the active oxygen species production. This active sites and radicals will cause oxidize organic pollutants and microbe adherent to the material surface.
In this study Ti thin films have been prepared by the sol-gel method from...
In this study Ti thin films have been prepared by the sol-gel method from...
Effective Factors on the Shrinkage Porosity Defect of Ductile Iron in Centrifugal Casting
, M.Sc. Thesis Sharif University of Technology ; Varahram, Naser (Supervisor) ; Davami, Parviz (Supervisor)
Abstract
The present work has been planned to elaborately investigate the key parameters which affect the formation of shrinkage porosities during centrifugal casting of ductile cast iron pipes. The porosity defects can be mostly found in the Hot Mould centrifugal casting products and adversely affect the final mechanical properties of ductile iron pipes namely Ultimate Tensile Strength and Elongation.
In the first point of view, the created defects were detected through microstructural observations and the corresponding responsible mechanisms were also discussed. The results showed that the inner porosity is produced because solidification occurs from both the inner and outer surfaces...
In the first point of view, the created defects were detected through microstructural observations and the corresponding responsible mechanisms were also discussed. The results showed that the inner porosity is produced because solidification occurs from both the inner and outer surfaces...
Neural Network Design and Optimization for Porosity Estimation with Using Seismic Attributs
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor) ; Badakhshan, Amir (Supervisor)
Abstract
Todays, the most important thing in the oil and gas fields is how to find the main properteis as porosity and permeability; therefere in this project was tryed to estimate to correct porosity in the reservoir area with using estimated porosity from siesmic attributes. For this study Mishrif reservoir in Sarvak formation was selected and the used data are 3D siesmic and also corrected porosity estimated by analysing siesmic attributes from five wells. For combination sresmic and log data, Simulated Annealing was seleted as a Neural Network optimizer for this project.
Multi-Scale Lattice Boltzmann Simulation of Carbonate Rock Dissolution in Acidizing Process
, Ph.D. Dissertation Sharif University of Technology ; Ayatollahi, Shahabodin (Supervisor) ; Jamshidi, Saeed (Supervisor) ; Raoof, Amir (Co-Supervisor)
Abstract
During the Acidizing process in oil and gas reservoirs, the injected acid reacts with the rock grains, changes the rock pore structure and affects the flow conditions. Due to the presence of a large concentration gradient at the vicinity of the rock grains and the continuous changes in rock-fluid interfaces of the porous medium, the continuum assumption has been remained debatable for the effective local mass transport and effective molecular diffusion coefficients and the porosity-permeability relation in the continuum scale modeling of this process. Therefore, the need for pore scale modelling is evident. The novelty of this study relies in adapting the grid refinement method on the...
Comparison and Evaluation of the Performance of some Fundamental Models for Simulation of Naturally Fractured Hydrocarbon Reservoirs
, M.Sc. Thesis Sharif University of Technology ; Taghizadeh Manzari, Mehrdad (Supervisor)
Abstract
Fractured reservoirs show a different behavior from common reservoirs because of the existence of a broad network of fractures. This phenomenon makes it necessary to apply special methods for fractured reservoirs in the procedure of reservoir simulation. Since twenty percent of petroleum content in the world is buried in fractured reservoirs, investigating these reservoirs is of great importance.
The first step in simulation of these kinds of reservoirs is to come up with a geometrical model which can be used to take the fracture network influence into account. In the course for reaching such an objective, various models have been developed which are based on specific assumptions and in...
The first step in simulation of these kinds of reservoirs is to come up with a geometrical model which can be used to take the fracture network influence into account. In the course for reaching such an objective, various models have been developed which are based on specific assumptions and in...
Comparison of Transfer Functions in Dual Porosity-Dual Permeability Models in Simulation of 3D Black-Oil Naturally Fractured Reservoirs Using Structured Grids
, M.Sc. Thesis Sharif University of Technology ; Taghizadeh Manzari, Mehrdad (Supervisor)
Abstract
In this work, simulation of 3D three-phase naturally fractured reservoirs is studied. Both Dual Porosity and Dual Porosity-Dual Permeability models which are commonly used in commercial softwares such as ECLIPSE and CMG, are utilized. The governing equations include the mass (in Black-oil model) and linear momentum (in Darcy law form) equations, which are converted into pressure equations and a set of transport equations for the saturations and mole fractions of phases. These equations are solved once for the matrix domain and subsequently for the fracture domain. These two set of equations are coupled through transfer functions. The accuracy of computations significantly depends on how...
1D Simulation of Naturally Fractured Oil Reservoir Flow with High Resolution Central Scheme Using Black-Oil Model
, M.Sc. Thesis Sharif University of Technology ; Taghizadeh Manzari, Mehrdad (Supervisor)
Abstract
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...
Optical Properties of Gel Cast and Sintered Alumina Ceramics
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor)
Abstract
In this process transparent polycrystalline alumina ceramic was provided by submicron alumina gel casting and spark plasma sintering. The monomer system in this process including met acrylamide and methylene bis acrylamide was chosen as a monomer and cross linker. These two agents comprise 5%wt of the precursor with the ratio of 3 to 1 respectively. With the optimization of Dolapix CE64 as a dispersant and providing the suspension with 76%wt, a greenware with the density of 56.3% wt was obtained. Differential thermal analysis of green body showed that the existing monomers are removed by the time the body reaches 550°C. In order to access high real in-line transmittance, the microstructure...
History Matching and Performance Prediction of Naturally Fractured Petroleum Reservoir Based on the Recovery Curve Method
, Ph.D. Dissertation Sharif University of Technology ; Massihi, Mohsen (Supervisor) ; Ghazanfari, Mohammad Hossein (Supervisor) ; Heinemann, Zoltan (Co-Advisor)
Abstract
The discrete fracture network and continuous fracture network are among the most widely used methods to model naturally fractured reservoirs. Each method faces particular limitations. The recently introduced recovery curve method (RCM) is believed to meet the limitations of the common methods. In the RCM the recovery curves are used to more realistically describe matrix-fracture interactions. It is necessary to present appropriate solutions to apply the RCM in the real fileds and also to evaluate it based on the historical production data. In this work at first, the basics of the RCM are presented then with a simple column model this method is validated. Then in a column model and a field...
Fracture Reservoir Simulation Using Finite Element Method with Logarithmic Shape Functions
, M.Sc. Thesis Sharif University of Technology ; Massihi, Mohsen (Supervisor) ; Shojaei, Akbar (Supervisor)
Abstract
Oil reservoir simulation serves an important role in forecasting oil production. This forecast, in turn, helps to devise a production scheme for hydrocarbon reservoirs which is one of main objectives of reservoir management team. In this research, using the idea of logarithmic distribution of reservoir fluid pressure around a wellbore, a new method for simulation of naturally fractured reservoir is developed. This method is shown to be more fast and accurate than conventional methods in reservoir simulation. In this method Dual-Porosity formulation is used for description of fluid flow in fractured reservoirs. The governing equations then were discretized by Galerkin Finite element method in...
The Application of Signal Processing in Oil Well Logging
, M.Sc. Thesis Sharif University of Technology ; Hajsadeghi, Khosro (Supervisor)
Abstract
Determining the porosity, water saturation and permeability values in the reservoir rock, are major steps in the petroleum engineering and formation evaluation. Today in the oil industry, these parameters are obtained using Helium gas injection technique on core (Plug) samples. However, the coring operation is difficult and costly. In addition, there isn't the possibility of coring in some of wells, such as horizontal wells. In fact, the present research is the modelling of artificial neural networks to estimate permeability in one of the Iranian oil field reservoirs by using oil well logging data. In this research, MLP neural network has been used and for network training, the evolutionary...
Study and Development of Dual Porosity/Permeability Models for Simulation of Forced Gravity Drainage Mechanism in Fractured Porous Media
, M.Sc. Thesis Sharif University of Technology ; Massihi, Mohsen (Supervisor) ; Gerami, Shahab (Supervisor) ; Ganjeh Ghazvini, Mostafa (Co-Advisor)
Abstract
The available investigations show that gravity drainage mechanism in fractured reservoir make a high recovery factor in comparison with other mechanisms. In recent years, the forced gravity drainage assisted by gas injection is also introduced; despite of its importance there is no comprehensive modeling study in the literature. The fractured reservoir is simulated frequently by dual porosity models in which the transfer function is the key issue for this method of simulation. This study makes an effort by comparison of different transfer functions with fine grid simulation results of a single block model, in order to evaluate their ability for simulation of forced gravity drainage...
Utilization of CT Scan Technique to Manipulate the Heterogeneity Effect
in Reservoir Rock Properties Determination
,
M.Sc. Thesis
Sharif University of Technology
;
Ayatollahi, Shahabodin
(Supervisor)
;
Fazel Abdol Abadi, Babak
(Supervisor)
;
Nematzadeh, Mostafa
(Co-Advisor)
Abstract
Petrophysical properties of reservoir rocks are of the most important parameters in fluid flow simulation and reservoir characterization. Although in core laboratories some well-known procedures for determination of these parameters are applied, in almost all of them the rocks are assumed to be homogeneous and their properties are taken up as identical in all directions. To eliminate these unrealistic assumptions, an accurate, non-destructive technique with appropriate degree of resolution is required for recognition of internal heterogeneity of cores. Medical “CT Scanner” is one of these techniques whose information in conjunction of conventional experiments could reduce their limitations...
A Proper Method of Upscaling Permeability data in a Typical Iranian Reservoir
, M.Sc. Thesis Sharif University of Technology ; Shadizadeh, Reza (Supervisor) ; Jonoud, Sima (Co-Supervisor)
Abstract
In this paper we have tried to mention a proper method of upscaling permeability data in a typical Iranian reservoir. Firstly a literature review is made on some common upscaling methods witch have been used so far. We introduced common upscaling methods like full tensor method, streamline method, stone method , vertical equilibrium method and also Kyte & Berry method. Additionally we have explained their advantages and also disadvantages. After selecting two upscaling methods, Kyte & Berry method and vertical equilibrium method, we applied these algorithms for upscaling of permeability data of Soroosh Oil Field. Soroosh oilfield is a heavy oil, Iranian reservoir located in Persian Gulf....