Sharif Digital Repository

In this thesis, the semi-hinged connections such as double-angle connections, which are welded to the beam web and bolted to the column flange, are investigated. In this study it's tried to establish the effect of clearance setback between beam end and column flange and/or web. When the beam rotates, it is desirable to avoid the bottom flange of the beam bearing against the column as this can induce large forces in the connection. The usual way of achieving this is to ensure that the connection extends at least a few millimeters beyond the end of the beam. For this purpose, several connections are designed and considered, based on two different shear capacities for the beam. For each... 

The receptivity, transition and stability mechanisms of supersonic and hypersonic boundary layers to freestream disturbances are one of the most complex studies in fluid mechanics. It is well known that turbulent flows generate much higher shear forces on the surface of vehicles and hence much higher viscous heating rates than a laminar flow would at the same flight conditions. Therefore, the accurate prediction of boundary layer behavior is a critical part of the aerodynamic design of high-speed vehicles and thermal protection systems. Formation of a bow shock in front of the vehicle makes the receptivity of flow-field more complex than and different from those of low-speed subsonics. Since... 

In this research, surface reaction phenomenon in porous media has been numerically simulated in pore scale. The main interesting part in this kind of physics is surface reaction exposed to a flow field. In this regard, an in-house code, based on LBM was developed. To speed-up our simulation, parallel computing was used on a GPU platform leading to a significant speed-up. Also, to model a real complex geometry, X-CT and MRI medical imaging technique were used to accurately model several complex 3D geometries. While, image processing technique was used to model our 2D geometries. The basic equilibrium equation of isopropanol dehydrogenation was considered to simulate and to analize chemical... 

One of the important questions in mathematics is generalized. In case of metric spaces, one of the questions is: Can we extend notions of Riemannian geometry to arbitrary metric spaces smoothly? Ricci curvature is one of the most important concepts in differential geometry. Ricci curvature is defined for the Riemannian manifold and has many applications in mathematics and physics like Einstein’s equation in relativity theory. There is a good notion for a metric space having “sectional curvature bounded below by K” or “sectional curvature bounded above by K”, due to Alexandrov. Can we define the concept of Ricci curvature in metric space? A motivation for this question comes from Gromov’s... 

Seismic design codes reduce loads by using response modification factor. Because of the reserved strength in structural elements and capacity of structure to dissipate energy, structures can be designed for lower seismic loads. This factor has modified over time. In this thesis, the effect of the reduction in behavior factor on the response of two kinds of reinforced concrete systems were evaluated. Moment resisting frames and dual systems with different heights and regularity in plan, heve been design according to the behavior factor which is recommended in the 3rd edition of the Iranian codes of practice for seismic resistance design of buildings (Standard No. 2800). Drift and...