A proprietary Liscic/Petrofer cylindrical Inconel 600 probe of 50-mm diameter and 200-mm length which was instrumented with three thermocouples on the same radius of the crosssection at the middle of the length was used to determine the differences in quenching performance of two vegetable oils, palm oil and canola oil, and they were compared to a locally produced conventional petroleum oil quenchant. The cooling curves and heat transfer performance of these oils were determined at different bath temperatures and agitation rates. The work was performed at the Quenching Research Centre located at the Faculty for Mechanical Engineering, University of Zagreb, Croatia. The results of this comparative study are reported herein.

Partial transmit sequence (PTS) using metaheuristic optimization methods can achieve a very good compromise between peak-to-average power ratio (PAPR) mitigation of orthogonal frequency division multiplexing (OFDM) signals and complexity. However, one neglected problem is that the side information (SI) needed for demodulation leads to PAPR regrowth. To overcome this issue, we propose a joint optimization scheme called Side inforMation and pARtial Transmit sEquence optimizatioN (SMARTEN) in which the SI is taken into account. We show that the proposed SI allows to correctly demodulate the OFDM symbol with a small energy efficiency loss. Then, we evaluate SMARTEN with genetic algorithm and simulated annealing metaheuristics. It is shown that not only the PAPR regrowth is eliminated but PAPR can be smaller than the one achieved by the conventional PTS when SI is not added to the OFDM symbol. We also provide an efficient implementation scheme, where we can exchange complexity by precomputing and storing the SI signal.