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In this paper, the effective parameters in access time of a low earth orbit (LEO) satellite, in a ground user, are studied and outcome of each one is estimated on it. Then the total access time of a single LEO satellite has been maximized. For this purpose, the inclination angle of orbit, to the equator, has been optimized in various satellite altitudes and ground station’s latitudes. The obtained results, once considered along with the power supply issue, give a comprehensive vision for LEO satellite orbit design. Then the satellite access to the sun, as the energy source, has also been evaluated. Simulations have been done by the satellite tool kit (STK) software.

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The English narrative of "the adventure of Hajji Baba of Ispahan"[1] seems to be one of the controversial literal texts for the Iranian readership with social criticism interest. This paper intends, not to refute or redeem the validity claims of this historical actualized reading or to offer an alternative, but, to put it into perspective of a spectrum of possibilities and to show how and under what contingencies, the text can actualize some other rival and salient interpretations that reverberate our contemporary horizons of social reality. Using the Ricoeurian theories of literature by applying his theory of "surplus of meaning" on the text we suggest how "The World of Text " has the potential to have different readings and in the next step, by analyzing "The World of Reader" and its dialectical relations with the world of text, we exhibit the important role of "reading" as the act of Self Reflection.

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Abstract- In this paper, two-dimensional natural convection heat transfer in semi ellipse cavities is investigated using lattice Boltzmann method. The Prandtl number is taken as 0.71 that corresponds to that of air. Heat transfer and flow pattern are predicted at various Rayleigh numbers ranging from 104 to 106 for different aspect ratios. By increasing of the aspect ratio, the heat transfer rate in the cavity is increased for low Rayleigh numbers, but it is decreased for high Rayleigh numbers. The obtained results of the lattice Boltzmann method are validated with those presented in the literature and show that the lattice Boltzmann method can simulate heat transfer and flow pattern in complex cavities. Analysis of heat transfer in a semi-ellipse cavity using second order boundary condition on curved surfaces is among the novelties of the present work.

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The high ductile of steel moment-resisting frames (SMRFs) during earthquakes has been challenged due to the brittle fractures of their welded (rigid) beam to column connections. Consequently, SMRFs have suffered severe damages and have produced collapse in main structural members (such as beams and columns). During previous years, energy dissipative devices in connections have been developed by researchers to resolve the ductility problem in rigid beam to column connections of SMRFs. Circular pipe steel damper (CPSD) proposed as a type of steel damper can indicate and dissipate seismic energy mainly through inelastic deformation. Among steel dampers such as shear panel damper, the advantage of CPSD is to resiste applied load in all direction. Under cyclic loading the circular shape of CPSD can change to elliptical shape which causes an extra energy in its absorption capacity. The previous study indicated that the stress concentration was high at both ends in the loading direction. The maximum stress was also observed at lower ends in the direction of loading. Henec, finding the best shape of cross section can enhance the behaviour of pipe steel damper (PSD). In this study, ellipse PSD (EPSD) was proposed for improving rigid beam to column connections of steel structures. For investigating the performance of the proposed EPSD, the behavior of a rigid connection with the common slit steel damper (SSD) SSD was assessed subjected to cyclic load in ABAQUS software. The proposed EPSD has the same weight in comparison with that of the common CPSD. The results of assessment were shown that in the energy dissipation of the proposed EPSD and CPSD subjected to cyclic load is equal to 11.11 kJ and 9.11 kJ, respectively. Thus, the proposed damper in comparison with CPSD can effectively contribute to about 22% of the total dissipated energy. The distribution of stress in the proposed EPSD in comparison with that of CPSD was also uniformly caused in the hight of EPSD. Furthermore, the performance of a rigid beam to column connection equipped with the proposed EPSD and SSD in subjected to cyclic loading was compared. The results revealed that EPSD in the rigid connection increased to about 63% of the total dissipated energy. Due to the distribution of stresses in more area, the strength of the proposed damper increases. Finally, the performance of a rigid beam to column connection equipped with the proposed EPSD and the welded connection in subjected to cyclic loading effectively was compared. The results demonstrated that the connection equipped with the proposed EPSD colud withstand a large number of loading cycles until the failure. Therefore, the proposed EPSD can be used instead of welded connection in SMRFs.