Sharif Digital Repository

In this thesis the graphene-based magnetic nanocatalyst was synthesized. The surface of this catalyst was cavered by silica and AgNPs. In addithion of simple sepration by magnetbar, yeild of reaction was promoted by surface modification. Catalyst structure was verified by transmission electron microscopy , scanning electron microscope, fourier transform infrared spectroscopy, X-ray diffraction and Energy dispersive spectroscopy.At the end catalytic activity was examined by oxidation reaction in persense of different alcohols. The oxidation of benzylic alcohol with electron withdrawing substituents was more difficult and the yield was lower, but electron donor substituents effect positively... 

There is a major interest to manufacturers of automobile and aerospace parts towards the tailor-welded blanks (TWBs) to reduce the weight and cost of the parts and improve their performance. In this work, formability of four groups of TWBs (two groups with similar thicknesses and different steels and two groups with similar steels and different thicknesses) are investigated. To produce the TWBs, DX54, E275 and E335 steel sheets were used. The results indicate that the inclined laser beam causes the sample failure from the weld zone in the tensile test. Setting the focal point on the top surface of the sheets results in enhancement of yield strength in comparison to the other positions. ... 

Impulsive waves generated by landslides and slamming on horizontal cylindrical members of a jacket are examples of phenomena which cause damage on structures and endanger human life. Importance of wave generated by land slide was a motivation for a large number of analytical, experimental and numerical studies. Recently, numerical methods that do not use a grid have been used in order simulation and prediction of damage in these sophisticated hydrodynamic problems. One of these modern methods is Smoothed Particle Hydrodynamics (SPH). A general model based on Smoothed Particle Hydrodynamics, “SPHysics”, was developed jointly by researchers to promote the development and use of SPH within the... 

Complicated theories dominated toward interacting of coastal regions resulted from its nature. Besides of that interference of human activities for acquiring beneficial aspects of shorelines causes environmental considerations to be challenged. One of the main factors for resolving this challenge is to obtain adequate information from hydrodynamic process and sediment regime. In spite of scientific researches that carried out along past three decades for understanding the exact mechanism of along shore sediment transport, it was not fully developed. One of the main reasons of uncertainty for forecasting the sediment regime regarded not exact knowledge of how sediment act in different... 

The present research has dealt with developing theoretic basis for technology of a modern and beneficial robot. There has been an old aspiration to attain some machine which can enclose body and move exactly in concert with it so as to maximize human might and endurance via powerful actuators. Exoskeleton robot is a recent successful invention regarding this aspiration, the lower-limbs type of which being sufficient for enhancing gait and load carrying capabilities.
Modeling the dynamics of this robot is very fundamental and was done thoroughly for the first time in this research. In the available articles, at most, simplified models are investigated. Mechanical structure was selected... 

Synthetic polymers have a high capacity to provide and manufacture the pieces used in tissue engineering. However, optimizing the biocompatibility, bioresorbableility and mechanical properties simultaneous with processability of material is complicated and requires a lot of effort at designing different parts of the system. On the other hand, due to existence of secondary bonds (such as metal-ligand coordination or hydrogen bond) supramolecular polymers are able to respond to some stimuli such as temperature, pH, or pressure, which is important in terms of dynamic nature of interaction between the living cells and the external matrix of cell. Recently there have been extensive studies on... 

Bluff bodies are commonly used to stabilize flames in many high-speed flow applications. V-gutters are one of the most common bluff bodies that are mainly used in ramjet combustors and turbojet or turbofan afterburners for flameholding. Aerodynamic characteristics of flow behind V-gutter has crucial effect on mechanism of flame stabilization, therefore more experimental investigations still seem to be necessary in this area. Particle Image Velocimetry technique which has high temporal and spatial resolution has been used in this research in order to better investigate the structure and dynamics of this unsteady and complex flow filed. Experiments were done on a reference V-gutter in... 

Precise adjustment of orientation is vital in many important applications of satellites. Besides, in order to have sustainable power source and to reduce heavy costs of launching deployable solar arrays with large area to mass ratio are utilized. The vibrations in these flexible parts and attitude dynamics of the main hub influence eachother mutually. Thus, simultaneous attitude and vibrations control is of noticeable significance. In this thesis considering new details such as multi-section solar panels, the governing dynamic partial differential equations (PDE) are derived via Hamilton principle. In order that errors arised from discretized models be eliminated and just using regular...