Shape memory alloys are considered as novel materials, and during the recent decades, these materials are increasingly used with different applications in various fields of science and engineering. Shaped memory alloys are extensively used in the field of structures and earthquake engineering. These alloys are so expensive, and they are not sufficiently economical to be used in structures, so scholars sought to find a combination usage of these materials along with steel in order to achieve the maximum efficiency. We can make any structure resistant enough against the dynamic loads and forces exerted due to earthquakes, by placing a new member in the structure, so called Damper, which is regarded as a factor with a capability of dissipating the energy. In the present paper, an elevated tank with a capacity of 1500 m 3 and frame-shaped base of 37.5 m in height, equipped with SMA damper at the tank-to-beam connection has been analyzed. It should be noted that the SMA material was used on first and seventh storey of the frame-shaped base. A numerical model of the tank was developed using Abaqus software and it was analyzed by applying EL-Centro earthquake record. Then, the best placement states of the SMA dampers indicating a better seismic behaviour were proposed. The findings indicate that an elevated tank with SMA damper has a better seismic behaviour, especially in the upper section of the beam, compared to other models.

Propylene glycol (PG), classed as alcohol, has been used in many industrial additives. Leaching PG in aquatic environments would cause a significant decrease in dissolved oxygen, and this is the main reason for treatment of runoffs and wastewater contaminated with this pollutant. Previous researches on PG removal from wastewater indicate that biological methods are more economically suitable. Therefore, a new biological reactor was introduced and used for the treatment of wastewater containing PG. Two main approaches for increasing removal efficiency in presented research are utilizing two serial lab-scale Sequencing Batch Reactors and feed backward connection between these reactors. This novel reactor was named Feed Backward Serial Sequencing Batch Reactor. Moreover, response surface method was used for modeling of PG treatment and investigation of interactions and simultaneous effects of independent parameters. Retention time, influent COD, and flow recirculation percentage were considered as independent variables, where COD removal efficiency was the dependent variable. According to the results, the best COD removal efficiency was 47%, and it was achieved in 3.52 h retention time, 1667.76 mg/L influent COD, and 23.33% flow recirculation percentage. Based on the results of the presented research, PG treatment with the presented reactor is feasible.

This study introduces the new biological reactor that called serial sequencing batch moving bed reactor. In this research, this reactor was used for treatment of hospital wastewater. Furthermore, three independent variables (retention time, pollutant loading and media filling percentage) were investigated. For the first time, modeling of COD removal percentage (as the dependent variable) in hospital wastewater treatment was investigated by using of response surface methodology. According to the results, the COD removal efficiency increased from 58 to 91%, when pollutant loading decreased from 0.38 to 0.3 kgCOD/kgMLSS. Also, COD removal efficiency increased from 38 to 86% when retention time increased from 16.48 to 58.52 h. According to the results, the media filling percentage had the minimum effect on the COD removal efficiency, so that, COD removal efficiency increased from 63 to 78% with increasing in media filling percentage from 19.77 to 45%. The results revealed that the optimum condition to achieving the highest COD removal efficiency was at the retention time of 46.59 h, pollutant loading of 0.34 kgCOD/kgMLSS and media filling percentage of 42.24%. According to this research results, this reactor have high efficiency in hospital wastewater treatment.