## 4 Discussion  
Following the measurements made on the seeds from the hybrids subjected to dimensional analysis, the following dimensions were obtained:  
- for SUM 96521: a = 8.1-14.8 mm; b = 6.7-11.8 mm; c = 3.5-7.8 mm;  
- for LG 2244: a = 5.5-13.1 mm; b = 6.2-10.3 mm; c = 3.9-8.7 mm;  
- for Kalista: a = 6.2-11.8 mm; b = 5.1-10.1 mm; c = 4.2-7.6 mm.  
The hybrid with the largest mass was SUM 96521, having the average mass of 0.304 kg.  
All analyzed hybrids had yields (M\({}_{\rm s}\)/M\({}_{\rm d}\)) over 90%, the highest being in the hybrid LG 2244 of 94.45%. The hybrid with the most uniform seed sizes was Kalista.  
For the dent-type corn hybrid, the variation between the maximum and minimum sizes of the seeds was greater compared to those of the indurata-type corn hybrids.  
Considering the advantages that the cylindrical sieve with uniform rotation has over the plane sieves with rectilinear-alternative oscillatory motion (higher compactness of the separation system, smaller gauge, easier balancing of inertial forces, simpler transmissions, simpler and more effective unclogging of orifices, more favorable conditions for seeds to pass through the orifices, the possibility of increasing the efficiency of seed separation) as well as the fact that the productivity of the cylindrical sieve can be increased by using special devices mounted inside the sieve, it is justified that this sieve be used more in the construction of cleaning and calibration equipment, in the construction of combines, or as a stand-alone machine.  
Figure 14: Influence of sieve length on the calibration of corn seeds using the 5 mm \(\times\) 25 mm sieve at the revolution speed n = 33 rot/min.  
Figure 15: Influence of sieve length on the calibration of corn seeds using the 5 mm \(\times\) 25 mm sieve at the revolution speed n = 49 rot/min.  
The longer the length of the calibration cylinder, the easier the seeds whose thickness is close to the nominal size of the oblong hole can be separated.  
When determining the point of contact of the seeds with the cylindrical sieve, the following were found: the seed detached from the surface of the cylinder, at a height corresponding to the angle at the center \(\pi/2-\theta\), reached the surface of the cylinder again, at the height determined by the value of the angle \(\pi-\gamma\).  
Following the measurements, it was observed that for revolution speeds close in value, the number of separated seeds was approximately the same. Analyzing the influence, it can be seen that the best results were obtained for the lowest revolution speed (33 rot/min); good values were obtained for intermediate speeds; but when exceeding 38-40 rot/min, the number of separated seeds decreased and became uniform up to the highest revolution speed (49 rot/min), meaning that increased revolution speeds were not recommended.  
The results obtained were consistent with other studies in the field, showing that seed shape and the three dimensions, namely, length, width, and thickness, greatly influenced the process, but this also highlights the necessity to have a good calibration process and to obtain a uniform mass of seed and, subsequently, a good germination or further processing [30; 33; 34].