Multi-layered nature of the wall of the carotid-artery bifurcation on hemodynamic and mechanical stress and strain

, Article 2011 18th Iranian Conference of Biomedical Engineering, ICBME 2011 ; 2011 , Pages 84-89 ; 9781467310055 (ISBN) Nikparto, A ; Firoozabadi, B. D ; Sharif University of Technology

2011

Abstract

Arterial diseases, namely atherosclerosis, are believed to be a product of abnormal changes in both hemodynamic and non-hemodynamic factors. In order to explornmk,e the role of different factors in initiation and progression of this disease, a CFD technique was applied to study Interaction between the structure of the artery and blood flow for different suggested models that were used to describe mechanics of vessel wall. This study presents a three-dimensional, steady state simulation of blood flow through the single and double layered carotid artery bifurcation using fluid structure interaction (FSI) method. The wall shear stress and mechanical stress/strain are computed and analyzed under...

Simulation and optimization of a semi spherical air bearing

, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Volume 7, Issue PARTS A, B, C, D , 2012 , Pages 153-159 ; 9780791845233 (ISBN) Saidimanesh, M ; Shahiri, A ; Nikparto, A ; Sharif University of Technology

2012

Abstract

It is important to test the attitude control systems on satellites before they are launched in space. Traditionally this has been done by dropping the satellite, and firing the thrusters before the satellite makes a soft landing in a net. This method only allows a few seconds of testing and does not lend itself to the measurement of pointing accuracy. A better method is to mount the satellite on a spherical air bearing. In this paper behavior of a semi spherical air bearing is studied and analyzed in various conditions. These bearings are used in different applications such as simulation of approximately frictionless condition which is the satellite's situation in space. In this analysis...

Analysis of Effective Algorithms In Social Networks

, M.Sc. Thesis Sharif University of Technology Nikparto, Nastaran (Author) ; Safari, Mohammad Ali (Supervisor)

Abstract

A social network is a social structure made up of individuals (or organizations) called ”nodes”, which are tied by one or more specific types of interdependency. These networks are new forms of distributed larg media which actually plays a critical role in distributing information and news among the people. because of the size and autonomos aspect of these kind od medias, taking control of them seems impossible. with the best hope we could think of some ways to detect information cascades through network.for example we could select a set of nodes as sensor inorder to detect information cascades as effectively as possible. in this thesis we studied cascade detection problem in scenario based...

Assessment of Existing Offshore Platforms for In-Place Conditions

, M.Sc. Thesis Sharif University of Technology Bassamzadeh, Nastaran Sadat (Author) ; Golafshani, Ali Akbar (Supervisor)

Abstract

Assessment of existing jacket type offshore platforms in Persian Gulf for life extension is of great importance in the field of offshore platforms in recent years. The main question to answer is whether an existing platform is safe enough to be used beyond the design life. Evaluation of existing jacket type offshore platforms under extreme environmental (wave) loading in Persian Gulf is a part of this major assessment. Two general approaches exist in this context, deterministic and probabilistic assessment. In this thesis, a new probabilistic method (reliability analysis) to assess offshore structures under environmental loading (extreme wave) is introduced. This method is a...

Thermo-hydrodynamic modeling of a single bubble nozzle-diffuser phase change micropump

, Article 6th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM2008, Darmstadt, 23 June 2008 through 25 June 2008 ; Issue PART B , June , 2008 , Pages 1237-1243 ; 0791848345 (ISBN); 9780791848340 (ISBN) Saidi, M. S ; Saeedi, M. H ; Pirouzpanah, S ; Nikparto, A ; ASME ; Sharif University of Technology

2008

Abstract

Nowadays, the potential of phase change process in liquids at micro scale attracts the scientists to fabricate this type of micropumps. Such micropumps have widely found applications in industrial and medical equipments such as recent printers. Not using mechanical parts such as valves, and having small sizes and high and controllable mass flow rates are the advantages of these micropumps. In the nozzle diffuser phase change micropump a heat pulse generates a bubble in a chamber; therefore, the pressure pulse which is generated by the bubble, causes the bubble to expand suddenly with high rate, then the pressure of bubble reduces to the vapor pressure and causes negative rate of expansion to...

Study the Effect of Considering two Layered wall for Carotid Artery Bifurcation on Distribution of Hemodynamic and Non-Hemodynamic Parameters using a Fluid-Structure Interaction Method

, M.Sc. Thesis Sharif University of Technology Nikparto, Ali (Author) ; Dehghan Firoozabadi, Bahar (Supervisor) ; Saidi, Mohammad Said (Supervisor)

Abstract

It is known today that arterial diseases are among the leading cause of death in modern societies. More than 50% of deaths in western countries are mainly occurred as results of these diseases, namely atherosclerosis. In order to study risk factors and to understand the full process of how arterial diseases initiate and progress, many research topics have been introduced and studied. Researchers believe that mechanical factors such as Wall Shear Stress (WSS), Pressure distribution, Cyclic strain, Back flow zones and many other factors are responsible for initiation of atherosclerosis. Different patterns of Wall Shear Stress and Strain are seen in arteries. Among other factors outlined in...

Growth of Perovskite Film based on Lead Iodide by Controlling Deposition Parameters for Solar Cells Application

, M.Sc. Thesis Sharif University of Technology Tafazoli, Saeedeh (Author) ; Mohammadi, Mohammad Reza (Supervisor) ; Seyed Reihani, Morteza (Supervisor) ; Riahi, Nastaran (Co-Advisor)

Abstract

Perovskite solar cells, with high efficiency operation, have been candidated as a cost-effective and environmentally friendly technology. Despite the great progress, there are some primarily issues remained regarding to the perovskite film and its fabrication methods. A very common perovskite cell structure is FTO/TiO2/CH3NH3PbI3/Spiro-OMeTAD/Au. Although, this structure has some advantages, lack of full surface coverage of perovskite film leads researchers to put much effort on finding other constructions. This surface inhomogeneity reduces the amount of light absorption and therefore efficiency. One way to produce a complete and uniform film is applying mixed-halide composition; such as...

Solvent Engineering for Preparation of Perovskite Film based on Lead Iodide for Solar Cells Applications

, M.Sc. Thesis Sharif University of Technology Timasi, Nazanin (Author) ; Seyed Reyhani, Morteza (Supervisor) ; Mohammadi, Mohammad Reza (Supervisor) ; Riahi Noori, Nastaran (Co-Advisor)

Abstract

The microstructure, morphology and quality of the perovskite organic-inorganic layer as an absorber layer in perovskite solar cells has a significant role on the efficiency and energy conversion of the device. Different solvent engineering methods have been employed to prepare the perovskite layer with the desired properties and thier reproducibility have been studied. Herein, we applied a two-step solution approach by solvent engineering method, using solvents such as isopropyl alcohol, acetone and thier mixture, for preparation of lead iodide films. Moreover, their metallurgical and photovoltaic properties were investigated. The impact of solvent engineering, using solvents such as...