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Composition of clusters determined by cluster analysis (k-means method). Abbreviations: see Table 1.
| Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 |
|---|---|---|---|
| E80 (100 °C) | E80 (60 °C) | E100 (180 °C) | E100 (60 °C) |
| E50 (60 °C) | E80 (80 °C) | E80 (180 °C) | E100 (80 °C) |
| E50 (80 °C) | W (60 °C) | E50 (180 °C) | E100 (100 °C) |
| E50 (100 °C) | W (80 °C) | - | - |
| W (180 °C) | W (100 °C) | - | - |
