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Equal channel angular rolling process (ECAR) is one of the newest processes in the severe plastic deformation methods (SPD) that changes the mechanical properties of the sheet metal. In this study, the effects of ECAR process have been investigated on the corrosion behavior of the pure commercial copper samples. Five routs have been applied on the samples to investigate the mentioned parameters. Also, the corrosion rates were examined by the polarization and electrochemical impedance methods. The results show that the process has destructive effect on corrosion resistance of the samples. The results from SEM examination indicates that, with increasing the number of passes, the surface corrosion increases too and with increasing the passes pitting corrosion is clearly visible. Although with increasing the number of passes the uniformity of corrosion can be seen and positional mode is exited. Generally, the corrosion increases from the first pass to the second pass. Also, the more diameter and depth of corrosion is observed with increasing the pass number. The corrosion increase at the third pass and the corrosion type is pitting corrosion and uniform corrosion in the sample.

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Leed titanate as an ionic Perovskite is ferroelectric at the lower of the below 766 K, which is called the transition temperature (Curie temperature), and at the above of this temperature is in the paraelectric phase. Studying the influence of mechanical parameters on the ferroelectric properties of PbTiO3 is important in the industrial application (such as RAM) of PbTiO3. In this study, using the molecular dynamics simulation method, the stress-strain effects on the polarization of lead titanate in the ferroelectric phase have been investigated. For modeling the atomic potential and interactions between ions in the ferroelectric phase, the short-range Buckingham potential and long-range coulombic potential, and, in addition, the fourth-order potential of oscillatory springs using a shell model (a model for calculating the polarization of a system) has been used. In this study, the effects of mechanical stress-strain action in the ferroelectric phase were investigated in two tensile and compression uniaxial stress-strain. In tensile stress-strain mode, the application of external stress leads to an increase in the polarization of the system, while applying compression stress-strain results in the decrease of the polarization of the system, so that by applying stress-strain, the polarization of the system reaches zero.
 

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Today’s urban life has encountered with a number of challenges especially in social and spatial arenas. Socio-economic inequalities, sometimes, emerges in the form of spatial inequality. Tehran, as a metropolis and capital, enjoys effective system with higher sensitivities in national system. The city, though, with a multi and complex system has brought a large population under its arena but at the same time it is considered imbalanced with continuous growth and development. In other words, Tehran, despite a role model for macro socio-economic system, suffers from spatial disparity and imbalanced services. One of the most obvious and sharp characteristics of Tehran is its north-south spatial inequality and polarization thanks to modernisation and its elements such as cars and emerging business districts. In the post-1979 Islamic revolution, the gap between rich and poor and spatial inequality in Tehran has widened despite the promise otherwise. Urban planners and sociologists in Iran have conflicting views about the spatial disparity where some call it a historical trend and nothing to do with the globalisation process whereas others think vice versa. To know whether or not Tehran can be called a global city, the current paper tries to illustrate old and new emerging inequality patterns in Tehran. For that matter, the theory of’ Global City (propounded by Saskia Sassen) has been analyzed based on spatial maps between 1996 and 2006.