1 Subjects: “...causal loop diagram...”

2 Subjects: “...closed-loop...”

3 Subjects: “...closed-loop recycling...”

4 Subjects: “...closing the loop...”

5 Subjects: “...hardware-in-the-loop testing...”

6 Subjects: “...sensitivity loop...”

7 Subjects: “...coal-direct chemical looping combustion...”

8 Subjects: “...open-loop control systems...”

9 Subjects: “...causal loop diagram...”

10 Subjects: “...Abel-Grassmann's neutrosophic extended triplet loop...”

11 Subjects: “...causal loop diagram...”

12 Subjects: “...closed-loop green supply chain...”

13 Subjects: “...closed-loop circulation...”

14 Subjects: “...closed material loops...”

15 Subjects: “...loop order analysis...”

16 Subjects: “...heat recovery loop (HRL)...”

17 Subjects: “...hysteresis loops...”

18 Subjects: “...chemical looping reforming...”