A cold roll-bonding process is applied to fabricate an AA6061/AA5052/AA6061/AA5052 layered sheet. Two AA6061 and one AA5052 sheets of 2mm thickness, 40mm width and 300mm length are alternately stacked, then reduced to a thickness of 2.0 mm by multi-pass cold rolling after surface treatment such as degreasing and wire brushing. The rolling is performed at ambient temperature without lubricant using a 2-high mill with a roll diameter of 400 mm at a rolling speed of 6.0 m/sec. The roll-bonded AA6061/AA5052/AA6061/AA5052 layered sheet is then hardened by natural aging (T4) and artificial aging (T6) treatments. The microstructure of the as-roll bonded and the age-hardened Al sheets was revealed by SEM observation; the mechanical properties were investigated by tensile testing and hardness testing. After T4 and T6 aging treatment, the specimens had a recrystallization structure consisting of coarse equiaxed grains in both AA5052 and AA6061 regions. The as-roll-bonded specimen showed a clad structure in which the hardness of AA5052 regions was higher than that of AA6061 regions. However, after T4 and T6 aging treatment, specimens exhibited different structures, with hardness of AA6061 regions higher than that of AA5052 regions. Strengths of T6 and T4 age-treated specimens were found to increase by 1.55 and 1.36 times, respectively, compared to the value of the starting material.

Purpose: The National League for Nursing/Jeffries Simulation Theory (NLN/JST) is a middle-range theory widely used in nursing simulation education. Although the NLN/JST was revised in 2015, there is still no formal critique of the theory. The purpose of this study is to present a critique of the NLN/JST. Method: This study comprehensively analyzes and evaluates the theory using Fawcett and DeSanto-Madeya’s (2013) framework. Results: The theory demonstrates positive social and theoretical significance, testability, and empirical and pragmatic adequacy. Nevertheless, semantic clarity and internal consistency need to be made clearer. Conclusion: The NLN/JST is a suitable framework for nursing simulation education. The theory considers not only participants but also patients and systems as outcomes of simulation education, and is able to incorporate situation-specific backgrounds. That said, it is still necessary to develop a systematic nursing curriculum for clinical reasoning competence of both nursing students and nurses, given the wide range of clinical situations they may encounter.