The properties of metals can be substantially changed by various methods, one of them is using heat treatment processes. Moreover, ultrasonic testing is the most preferred and effective, nondestructive testing technique for characterization of mechanical material properties. Austenitic stainless steel AISI 304 serves in many applications due to high strength and corrosion resistance. In certain applications, it is important to evaluate the mechanical properties of AISI 304 stainless steel. In this study, the ultrasonic method (attenuation measurement technique) is used to evaluate the hardness of AISI 304 stainless steel samples which were heat treated at different levels. Due to the heat treatment process, each sample has its specific microstructure and hardness which attenuate ultrasonic waves appropriately. The ultrasonic and hardness test show that it is possible to evaluate the hardness of AISI 304 stainless steel by ultrasonic attenuation coefficient. In addition, the relationship between ultrasonic attenuation coefficients and time of heat treatment is investigated.

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This article studies the Artificial Groundwater Recharge (AGR) of the Esfarayen aquifer, in Iran, from the perspective of the strategic planning process. For this purpose, a SWOT systematic analysis was performed for the AGR of this aquifer, and its strengths, weaknesses, opportunities, and threats (SWOT) were identified. These factors were analyzed and ranked using Mikhailov's fuzzy analytic hierarchy process (AHP) and based on this analysis, prior strategies were proposed. The results showed that the share of two groups of threats and opportunities in higher priority factors was more than the two groups of strengths and weaknesses, so that the shares of threats and opportunities in the first half of the list of factors were 87.5% and 70% of the factors of these groups, respectively. Also, strengths have been ranked higher than weaknesses. Therefore, in selecting appropriate strategies for the future of the AGR of Esfarayen aquifer, priority should be given to ST type strategies; strategies that use the strengths of the system to try to eliminate external threats to the system. After ST type strategies, due to the high importance of opportunities, SO type strategies can also be adopted for the AGR of Esfarayen aquifer.