Sharif Digital Repository

Cardiovascular disease is responsible for a majority of health problem in developing countries. Heart diseases are the leading cause of death in the United State with approximately 40% of the death occurs by heart failures and coronary artery defects. Myocardial infarction is one of the diseases that occurs by coronay artery blockage. Cardiac tissue engineering (CTE) is an emerging field that holds great promise towards the development of innovative treatment strategies for heart disease. There are two common scaffolds for CTE, electrospun fiber mats and hydrogels. Although fibers are known as 3D environment for cells, they actually act as a 2D surface, because of lack of cell infilteration.... 

In this thesis, the notion of nowhere-zero flow on graphs in defined with values is an Abelian group. It is shown that the existence of nowhere-zero flow with values in H depends on only the cardinal of H. Also the existence of nowhere-zero flowwith values on Zk is equivalent to the existence of the nowhere-zero flow with values in the set 1,2,...,k-1 on group Z.It is a easily seen that the nowhere zero flow on the graph with bridge doesn’t exist. Also has been proved any graph with no bridge has nowhere-zero 6 flow.Concidentally, the existence of nowhere-zero 5 flow for graphs with no bridge isstill an open problem.In 3-flow case, recently it is shown that any 8-edge connected graph has... 

Studying the behavior of materials at high strain rate is necessary for design and analysis of structures subjected to impact loading. Therefore, design and construction of apparatuses that enable us for testing various materials under impact loading is very important. The split Hopkinson pressure bar test -one of the most important impact tests- is utilized for dynamic loading at constant strain rates ranging from 100 to 10000 1/s.
In this thesis, first we explain about the behavior of materials at high strain rates and then focus on the behavior of polymers -that are widely used in different industries- under impact loading. Also, basic concepts of polymeric Hopkinson pressure bar and... 

Spirocycles have been employed both as core structures and appended to the periphery of molecules in drug discovery. The major advantage that spirocycles offer as core structures is their inherent three-dimensional nature and concomitant ability to project functionality in all three dimensions. Spirocycles have been employed both as core structures and appended to the periphery of molecules in drug discovery. The major advantage that spiro cyclesoffer as core structures is their inherent three-dimensional nature and concomitant ability to project functionality in all three dimensions. However, to take full advantage of spirocycles, the ability to control stereochemistry at multiple positions... 

The concurrent flow of oil and water is a common occurrence in the field of multiphase flow in different fields including petroleum industry. In oil and gas, production engineers often face a situation in which more than one phase is flowing through the producers. In such conditions an accurate assessment of pressure loss inside the well plays a vital role in efficient and effective production planning. Changes in well orientation, wellbore diameter, reservoir and fluid properties as well as fluid flow rates are among parameters in which will affect the flow patterns that can occur inside a well during its life time. These flow patterns are created as a result of a competition between... 

Casing design is one of the most expensive parts in the drilling of oil wells, and any cost reduction with the basic design of these casing strings will significantly reduce the total cost of the operation. In recent years, occurring scenarios-based casing design has become popular; Because in many cases, it eliminates non-occurring scenarios such as gas kick and saves on drilling costs. In this study, we have tried to investigate all scenarios that may occur during the lifetime of the well, whether drilling or production, and for each well, based on its own field information, possible scenarios for each casing part are selected separately and the applying loads are calculated. For this... 

It is more than a century to study qualitative and quantitative behavior of structures against earthquakes will be benefited from laboratory studies. In fact, the best method for observing the behavior of a structure during an earthquake is earthquake simulation on the structure. Today, the most effective way to do these tests is simulating of earthquake by using of Shaking Table. The shaking table consists of three main parts: electronic, hydraulic and mechanical. The accuracy of earthquake simulation’s results are very important. In recent years, numerous studies on the dynamic behavior of the above components and the interactions between these components are performed. In this study, we...