# Studies on the Energy Consumption of Material Cutting in the Onion Peeling Process
## 3 Results  
The results from the experiment are presented in Table 3, while Table 4 contains selected statistics for the dependent variable. In Table 3, the experimental results (arithmetic mean values of the dependent variables) obtained for the five-factor cross combination of the independent variables are summarized. The analysis of the regression function for the unit energy consumption of the \(E_{j}\) process was performed in five stages. The results from the final stage of the regression function analysis are summarized in Table 5. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \(v_{p}\) & \(h_{d}\) & \(p\) & \(d_{n}\) & \(E_{j}\) & \(d_{n}\) & \(E_{j}\) & \(d_{n}\) & \(E_{j}\) \\ \([\text{pcs}\!\cdot\!\min^{-1}]\) & \([\text{mm}]\) & \([\text{bar}]\) & \([\text{mm}]\) & \([\text{k}]\!\cdot\!\text{kg}^{-1}]\) & \([\text{mm}]\) & \([\text{k}]\!\cdot\!\text{kg}^{-1}]\) & \([\text{mm}]\) & \([\text{k}]\!\cdot\!\text{kg}^{-1}]\) \\ \hline \hline \multirow{8}{*}{30} & \multirow{8}{*}{20} & 4 & \multirow{8}{*}{1.5} & 55.1133 & \multirow{8}{*}{136.4845} & 55.0025 & 56.8005 \\  & & 5 & & 75.1148 & & 77.6213 & & 78.5865 \\  & & 6 & & 106.6335 & & 106.5929 & & 107.1472 \\  & & 7 & & 136.4845 & & 139.8616 & & 144.5362 \\ \cline{2-10}  & & 4 & & 52.7418 & & 53.6988 & & 54.9114 \\  & & 5 & & 74.7079 & & 76.3210 & & 75.8991 \\  & & 6 & & 101.5387 & & 106.6241 & & 105.3129 \\  & & 7 & & 129.4598 & & 134.0152 & & 140.6034 \\ \cline{2-10}  & & 4 & & 51.6940 & & 52.6541 & & 53.3708 \\  & & 5 & & 69.0028 & & 73.7363 & & 72.5320 \\  & & 6 & & 98.1014 & & 98.2668 & & 103.6590 \\  & & 7 & & 126.3576 & & 132.0104 & & 130.1968 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The results of the experimental tests obtained during the implementation of the experiment according to the five-factor cross combination. From the test results presented, it can be seen that the value of \(E_{j}\) decreases according to the graph of the polynomial function of the second degree as the material feed rate \(v_{p}\) increases. The lowest values of \(E_{j}\) obtained for material feed rate \(v_{p}=60\left[\text{pcs. }\cdot\text{min}^{-1}\right]\) and obtained for the combinations of values of the independent variables shown in the graphs represented on average 41.86% of the values of \(E_{j}\) obtained for \(v_{p}=30\left[\text{pcs.}\cdot\text{min}^{-1}\right]\). Detailed results are presented in Figure 8. For a constant value of \(v_{p}\), the unit energy consumption of the process \(E_{j}\) was found to increase strongly together with the increase in the number of peeling nozzles \(n_{d}\) and the value of the pressure \(p\) of the air supplying them. An increase in the distance of the air nozzles from the material \(h_{d}\), on the other hand, was found to result in a slight decrease in the unit energy intensity of the process \(E_{j}\). Figure 9 illustrates the dependence of unit energy consumption \(E_{j}\) on the air pressure supplying the skin removal system \(p\). From these graphs, a strong positive correlation between these quantities can be evinced. In the case of the system of the variables describing the values included in the graphs, the unit energy consumption for the peeling process \(E_{j}\) at the pressure \(p=4\) bar was, on average, 50.46% lower than that at \(p=7\) bar. In the case of constancy of the other explanatory variables, this dependence can be approximated by a decreasing linear function. The highest values of \(E_{j}\) obtained for the value \(h_{d}=20\) mm were, on average, 9.70% higher than the values obtained for \(h_{d}=40\) mm. Analyzing the remaining data, the \(E_{j}\) values obtained with the combinations of values of the independent variables considered in the graphs for \(n_{d}=2\) were, on average, 56.55% lower than those obtained for \(n_{d}=4\). Finally, the extreme values of the dependent variables are presented in Table 6.