Sharif Digital Repository

In this study, a novel multi-scale hierarchical method has been employed to explore the role of edge dislocation on Nano-plates with hexagonal atomic structure in large deformation. multiscale hierarchical atomistic/molecular dynamics (MD) finite element (FE) coupling methods are proposed to demonstrate the impact of dislocation on mechanical properties of Magnesium in large deformation. The atomic nonlinear elastic parameters are attained via computing first-order derivation of stress with respect to strain of Representative Volume Element (RVE). To associate between atomistic and continuum level, the mechanical characteristics are captured in the atomistic scale and transferred to the... 

In previous decades, easy access to material and low cost human power allow the product process to be performed in a preferred way. The limit in amount of material, economy, and the efficiency of the model has not been influential like these days. Today, the effective use of material and consideration of an economic model have great importance. It is obvious that a process of designing implies optimizing which the range of its using is also continuing in many engineering sciences. Many optimization issues contain discrete nature. Many of searching spaces that we encounter in the real world applications are not necessarily continuous as a condition which has crucial importance for classic... 

In this thesis, with using the holographic renormalization we study couple of recently discovered gravitational theories, New Massive Gravity and Critical Gravity. We show that the dual field theory to each of them, is logarithmic conformal field theory. Also we study the Topologically Massive Gravity at critical point with hamiltonian holographic renormalization which is completely different from another approachs that are used to analys this theory. We show that albeit the dual field theory to this gravitational theory is logarithmic conformal field theory, but we can define completely consistent Wald’s charges, holographic charges and Noether’s charges for it  

Isogeometric Analysis is one of the new methods for solving partial differential Equations which has special advantages compared to conventional methods such as the finite Element method. Some of these benefits can be used to approximate the geometry and solving the Equations governing the behavior of materials. Calculating the stress intensity factor at the tip of the Crack using classical method such as finite element method is done as well as IGA and gives Acceptable Results in linear range. Studying how to calculate these coefficients in combination with Isogeometric analysis method and comparing results with FEM due to novelty of the approach can have considerable importance for... 

Chemical flooding has great potential to recover significant fractions of remaining oil for medium to heavy oil reservoirs not applicable for thermal recovery techniques. Nowadays, with gradual crude oil price increase the chemical process is receiving renewed attention, however, illustration of the possibility of various chemical injection scenarios for medium to heavy oil reservoirs has not been clearly reported and these kinds of reservoirs require more investigation for the applicability of these techniques in the fields. The interfacial active molecules are responsible for providing low IFT range and water/oil emulsions which in many cases could improve the oil displacement efficiency.... 

In recent years, the application of base isolation as a seismic design strategy for reducing the effects of earthquake ground motion has become an advantageous method and much effort has been devoted to base isolation research and there has been a growing acceptance of this approach. In this research, the effect of using base isolators in reducing the dynamic forces of piers and abutments of bridges is studied. More specifically double-span bridges are the target of this research. After modeling a regular bridge in a typical analysis program, it is excited by different earthquake accelerograms and then the effect of using base isolators in dissipating the earthquake energy is investigated  

In this work, effects of information aggregation on risk attitude of Iranian individuals is being studied through two experiments. In these experiments a risk-free asset with a guaranteed revenue and a risky asset is introduced to each individual. Then the individual has to allocate a certain amount of money between two assets. In both experiments three treatments of control, separation and aggregation are defined in a way that the degree of information aggregation increases respectively. Given the specific treatment assigned to each individual, complementary information is presented, in orderto finalize the decision. Next a financial market simulation for a five year horizon is conducted to...