Sharif Digital Repository

This study presents a developed successive boundary element method to determine the sloshing natural frequencies, mode shapes and equivalent mechanical models for multi baffled 2D and axisymmetric containers with arbitrary geometries. The developed fluid model is based on the Laplace equation and Green's theorem. The governing equations of fluid dynamic and free surface boundary condition are also applied to proposed model. A zoning method is presented to model arbitrary arrangement of baffles in multi baffled axisymmetric tanks. The influence of each zone on neighboring zones is applied by introducing interface influence matrix which correlates the velocity potential of interfaces to their... 

In this research, I propose a macro-finance model with asymmetric information between firms and banks to investigate the capital misallocation effect of government interventions in financial markets of Iran’s economy, in terms of setting the price of “Transactional Loans”. In the presence of adverse selection, interest rate may be an instrument for screening lowproductive firms; however, the moral hazard problem of low productive firms with voluntary default, cancels out the filtering mechanism in high interest rates, if the cost of default for low-productive firms is low and judicial systems are poor in enforcing contracts. Hence, government repression/regulation policies do not affect the... 

Today’s organizations always encounter limitations on the way of achieving their goals. Budget constraint, inventory constraints, capital constraints are issues which complicates management decision making.
Global market has enabled manufacturers compete globally. Even position their factories in other countries and use of competitive advantages and other markets demand. This is why decision making in production and manufacturing domain has been complicated. Decision making in production and manufacturing should become faster and more precise in order to keep market competitiveness. Organization should make long term or strategic decisions and short term decisions about keeping the... 

Friction stir soldering (FSS) or brazing (FSB) as an emerging joining process, was first developed to resolve some shortcomings in FSLW and FSSLW such as excessive IMC layer thickness and confined bond area. Although it has advantages over conventional furnace soldering and/or brazing, including localized heating, less detrimental thermal effects on the substrates and capability to reduce the amount of voids at the joint interface. The aim of this study is to investigate the effects of rotational speed, traverse speed and plunge depth of the pinless tool on the shear strength and electrical resistivity of the copper-coated graphite-copper FSSed joints with the aid of Sn-37Pb solder alloy. At... 

In this project rotational barrier of C-N bond in 2-Cyanoethyl-Pyrrolidine-1-Carbodithioate has been studied using DNMR spectroscopy. Spectra were taken at various temperatures, and then with simulation of bandshape broadening pattern, rate constants of exchanges were obtained for all temperatures. For simulation of line-shape broadening SpinWorks software was used,which with two interfaces made possible simulation with two bandshape simulator programs, DNMR and MEXICO. The rate constants obtained from simulations, were used for calculation of thermodynamic activation parameters (ΔG#, ΔH#, ΔS# and Ea#). Experimental ΔG# value of 18.4 Kcal mol-1 for 2-Cyanoethyl-Pyrrolidine-1-Carboditioate in... 

In order to simplify the dynamic analysis of soil-structure systems, the structural element of the foundation is usually assumed to be rigid. While the rigid foundation assumption is acceptable for block-type machine foundations, it may influence the dynamic response of other structures such as structures with a central rigid core. Previous research has shown that the flexibility of the foundation structural elements affect dynamic stiffness of underlying soil so it can change the structural response. The aim of this thesis is to study the influence of foundation flexibility on the global response of soil-structure systems including structures with a rigid core. Since the response of the... 

Explaining the angular momentum of the cosmological structures is an essential part of the structure formation theory, and it is not fully understood yet. The Tidal Torque Theory (TTT) is the standard explanation of the initial angular momentum of the halos based on the gravitational instability picture. It predicts the angular momentum growth with linear approximation and has been confirmed for linear stages of proto-halos, but the final halo is a highly non-linear object. Nonlinear effects are hard to model, however, we propose a new mechanism for the nonlinear evolution of the halos. We suggest that when two halos pass by each other, their angular momentum changes with a similar mechanism...