فصلنامه مدل سازی در مهندسی
پیاپی 37 (تابستان 1393)

In this study the effects of the evaporation/condensation phenomena and the evaporative gas cooling due to heat exchange with liquid phase is investigated on CO2 absorption in a venturi scrubber. The results show that despite the short residence time of gas in this type of scrubbers، the effects of heat and mass transfer between gas and liquid on the separation efficiency of CO2 is remarkable. The main reasons include (1) the high heat and mass transfer coefficients، due to high relative velocity between gas and droplets، and (2) the large heat and mass surface area، resulted from the fine atomization of injected liquid. The effect of operational parameters on absorption efficiency in non-isothermal operation is investigated. The results show that the decreasing the temperature of inlet gas and increasing its humidity are two effective tools to increase absorption efficiency. In fact، installation of a gas cooling-humidifying system prior to venturi scrubbers is strongly recommended.

This paper models the 3D progressive collapse of a 3 story reinforced concrete symmetric/asymmetric building with different levels of mass eccentricity under earthquake loads. We investigate collapse propagation، from the first element to the entire of the buildings، through comparing the results obtained via evaluation of the nonlinear time history analyses. Our analyses signify that mass irregular distributions result in further local damages and consequently are led to a larger progressive collapse in torsional buildings. We found that collapse is tend to be concentrated in the positions with a high level of mass concentration and the collapse distributions are horizontal through the stories، but not vertical through the height of the building. When the value of mass eccentricity is increased، collapse initiation points tend to transfer to the flexible edges and the probability that the collapse is initiated from the columns is increased، too. Besides، the spread of the collapse is independent of the earthquake records and vary according to the level of mass eccentricity in structures. This gives the ability to predict collapse scenarios in similar symmetric/asymmetric buildings.

In this paper، for solving the Multi-Objective Multi-area Environmental Economic Load Dispatch، Cuckoo Optimization Algorithm is proposed. In resent year، the economic load dispatch is considered as a multi-area power systems problem، but، in none of these studies the environmental problem is not considered. Accordingly in this paper the model of pollution constraint is imposed and the terms of issue of the new model is considered. On the other hand، the cuckoo optimization algorithm is an evolutionary search algorithm which is proposed in recent years by researchers in various fields of engineering. However، the advantage of this algorithm for solving power systems has not been investigated. So، the ability of Cuckoo Optimization Algorithm for solving environmental economic load dispatch with respect to the contamination (the proposed model) in multi-area power systems is investigated. The proposed technique is applied on different issues in many single area systems (6، 10 and 40 generation unit) and the distribution of the economic burden of pollution provisions regarding the function of the immune system in single area (6 units، 30 buses). Finally، the proposed algorithm in solving economic load dispatch in the region of 4 units and two additional constraints is investigated. The performance of this algorithm is compared with other techniques which demonstrate the superiority of this method than the others.