## 3 Results and Discussion
### Droplet Drifiability  
According to other authors [13; 43; 56; 57; 64], the V100 is a valuable parameter to predict spray drift. The lower this parameter, the lower the portion of spray droplets below 100 \(\upmu\)m and, therefore, the predicted incidence of the spray drift. As it is displayed in Figure 11, V100 values were generally higher for the cannon-type nozzle in the CP and AP. This trend enhanced the spray drift generation during field spray application, as the cannon spout must spray at a longer distance from the target than the hand one in the conventional setting used in farms (Figure 1b). Nevertheless, the present study showed a different behavior of the two nozzle types in the droplet size spectra increase after the AP (liquid hose out of the spout body). Thus, for OP and XP, cannon spout presented lower V100 values when compared to the hand-type one (Figure 11). This finding might be relevant for the spray drift reduction, as it could indicate a higher interest in implementing OP and XP in the cannon spout. Indeed, in the case of the cannon-type nozzle, there was a consistent V100 reduction among consecutive hose positions. Thus, from a mean value of 68% in CP, the V100 mean value decreased to 8% in XP (Figure 11a). Within each liquid hose position, the combination of minimum LFR with maximum AS and maximum LFR with minimum AS deeply affected the driftability. These settings yielded mean V100 values of 49 \(\pm\) 2% (max LFR/ min AS) and 61 \(\pm\) 2% (min LFR/max AS) in CP (Figure 10a). AP gave V100 results between 21 \(\pm\) 1% (max LFR/ min AS) and 64 \(\pm\) 2% (min LFR/max AS). OP resulted in a range from 10 \(\pm\) 1% (max LFR/ min AS) to 21 \(\pm\) 1% (min LFR/max AS). Finally, XP values ranged from 5 \(\pm\) 1% (min LFR/ min AS) to 10 \(\pm\) 1% (min LFR/max AS) (Figure 10a). In a practical way, the best V100 reduction within each hose position was always achieved when the system was operated with the maximum LFR and minimum AS, confirming the marked influence of these operational parameters [53]. Comparing V100 values generated by pneumatic nozzles with those generated by the reference hydraulic nozzle (Figure 11a) Albuz(r) ATR iliac operated at 0.7 MPa pressure (dashed red line corresponding to V100 equal to 74%), it can be observed that similar values were obtained when the pneumatic nozzles were used in CP and combined with the highest AS (89.6 and 97.7 m s\({}^{-1}\)). Changing the hose position from AP to XP, all possible combinations of tested parameters reduced the V100 level compared with the reference nozzle. This finding reflects the capability of AP, OP and XP to generate droplet populations with a driftability similar to those produced by a wide range of conventional hydraulic nozzles characterized by different dimensions and operated in a wide range of liquid pressure. Specifically, the V100 values for XP were similar to those obtained using hydraulic air induction nozzles. Indeed, the cannon-type nozzle operated in the XP position and, combined with  
Figure 11: V100 (%) per liquid hose position (HP), liquid flow rate (LFR) and airflow speed (AS) for both the (**a**) cannon-type and (**b**) hand-type nozzles. Bars show the mean \(\pm\) Standard Error. The dashed lines represent the hydraulic reference nozzles, namely hollow cone conventional ATR iliac in red and air induction TVI 8001 in green (Albuz®), both operated at 0.7 MPa pressure. CP, conventional insertion of liquid hose position; AP, alternative position; OP, out position; XP, extreme position. the lowest AS, achieved V100 values fully comparable with those obtained with air induction nozzle Albuz(r) TVI8001 (V100 equal to 4%) marked with the dashed green line in Figure 11a. The minimum value achieved in the XP was 5%, so the droplet size can be considered similar to that of a conventional low-drift nozzle.