## 2 Materials and Methods
### Seed Sorting Using a Calibrator with Cylindrical Sieves  
Seed sorting can be achieved using equipment with plane or cylindrical sieves. Plane sieves perform separation by width and sometimes thickness (if the orifices are elongated) and they rely on vibration and an inclination angle to perform the separation. Their main shortcomings are represented by large equipment dimension; maintenance problems caused by vibrations; orifice clogging; and the seeds tending to gather in the center of the sieves, causing deformations due to weight. Cylindrical sieves present a series of advantages compared to plane sieves, including smaller gauge, simpler operation, lack of vibrations, more efficient separation in the sense that centrifugal force is added to the weight of the seeds, orifice unclogging systems of the seeds that could not pass through them that are much simpler and more efficient than the one from plane sieves, etc. The main shortcoming of these sieves is that the surface of the sieve is not fully used in the separation process. In order to find the most effective solutions in order to increase their efficiency, it is necessary to study the kinematics of the cylindrical sieves and the process of separating the seeds through their orifices. The tests regarding the calibration operation were performed on the CCM 2630 Modulated Cylindrical Calibrator (Figure 2), designed and manufactured at INMA Bucharest. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**No. **} & \multirow{2}{*}{**Hybrid/Sample**} & **Total Mass** & **Total No. of Seeds/** & \multirow{2}{*}{\(\eta=\) M\({}_{s}\)/M\({}_{t}\)} & **No. of** & **Seed Moisture/** \\  & & **(Seeds + Rachis)** & & **Mass of Seeds M\({}_{s}\)** & **(\%)** & **Rows/No. of** & **Rachis** \\  & & **M\({}_{t}\) (kg)** & & **(kg)** & **Seeds per Row** & **Moisture (\%)** \\ \hline
1 & SUM 96521/S1 & 0.290 & 601/0.262 & 90.34 & 14/44 & 8.46/8.31 \\
2 & SUM 96521/S2 & 0.343 & 722/0.311 & 90.67 & 16/46 & 8.31/8.45 \\
3 & SUM 96521/S3 & 0.284 & 509/0.268 & 91.54 & 12/43 & 8.78/8.22 \\
4 & SUM 96521/S4 & 0.252 & 531/0.260 & 92.06 & 12/45 & 8.74/8.17 \\
5 & SUM 96521/S5 & 0.322 & 668/0.232 & 90.05 & 16/42 & 8.25/8.16 \\
6 & LG 2244/S1 & 0.256 & 514/0.274 & 93.75 & 14/37 & 8.24/6.04 \\
7 & LG 2244/S2 & 0.200 & 439/0.240 & 94.45 & 12/37 & 3.78/5.83 \\
8 & LG 2244/S3 & 0.212 & 617/0.189 & 91.98 & 16/39 & 4.08/6.26 \\
9 & LG 2244/S4 & 0.204 & 618  
When establishing the technical-constructive solutions, the realization of high-performance equipment is characterized by processing capacity at the level of current requirements, specific consumption of energy and reduced materials, a high precision of the separation of seeds according to size (width and thickness), access to the active organs, maintenance, and easy operation. A module of the cylindrical calibrator consists of the following main parts: frame, calibration cylinder, sieve, drive support, feeding inlet, feeding funnel, exhaust funnel, doors, covers, protective guards, etc. The main technical characteristics of the sorter are shown in Table 2.  
Operation of the Cylindrical Calibrator  
The corn seeds are fed through the feeding inlet and inserted into the feeding funnel. By means of the vane group that has the vanes mounted at an angle to ensure a good feeding of the sieves, the seeds are introduced on their surface. The calibration cylinder can be equipped, depending on the technological requirements, with the same type of cylindrical sieves or with cylindrical sieves with different orifice sizes, with those with smaller sizes being mounted towards the product supply. The sieves receive the rotation