previous study . The remaining 30 polycyclic hydrocarbons (PCHCs) were sourced from the PubChem database . As shown in Fig. , these PCHCs predominantly comprise saturated cycloalkanes except for ten compounds (28.571%) containing unsaturated C=C bonds. This observation agrees with the fact that saturated hydrocarbons are often preferred for SAFs compared to unsaturated ones . The majority (77.143%) of compounds in Fig. exhibit pentagon ring configura�on, and nearly half (42.857%) contain triangular rings, consistent with the outcome reported earlier . The fuel properties such as gravimetric NHOC (NHOCG), volumetric NHOC (NHOCV), H/C ratio, and density (ρ) of these liquid PCHCs were obtained using the present ML are summarised in Table . Note that gravimetric NHOC (NHOCG) and density (ρ) are obtained from ML, and other proper�es/descriptors such as volumetric NHOC (NHOCV), H/C ra�o, and the total number of rings (Nring) are derived. The total number of rings (Nring) in Table can be obtained from RDKit or counted manually from the structures. As seen in the table, almost all these compounds contain either triangular rings or rectangular rings with acute angles or pentagon rings, indica�ng that they are strained with possibly higher internal energy. However, the number of total atoms descriptors, which is not independent, may be removed for new descriptor development for SAF.