## 4 Results
### Statistical Analysis  
Finally, the results of statistical tests aimed to evaluate the reliability of our data are presented. The results of the multiple range tests to show the number of groups created according to the data of CalPr and VerPr are described. For all of the evaluated data (all prototypes and their four configurations) the results of ANOVA indicate that the concentration of OF explains the variance on the Vout.  
Figure 13 represents the output of multiple range tests for each configuration of P1. Among these four configurations, the best results are obtained for the configurations 3 and 4. In these configurations, we find the highest differentiation in terms of generated groups. For configuration 3, the results of the test define nine groups (a to i), and for the fourth configuration eight groups (a to h) are defined. Each column of letters indicates a group of means within which there are no statistically significant differences. The first and the second configurations are very similar, and only seven groups can be identified (a to g). With data of the first configuration, it is not possible to distinguish between 12.5 and 15 g/L or between 17.5 and 20 mg/L. In the case of the second configuration, the lack of differentiation is found between 0 and 2.5 g/L and between 15 and 17.5 g/L. The standard deviation of the configurations is very low, being 0.041 g/L, 0.012 g/L, 0.018 g/L and 0.015 g/L for configurations 1 to 4 respectively.  
Figure 13: The graph presents a multi-range analysis for the four configurations where they are drawn by columns. Each column contains non-significant values between them. The different letters show that the values are statistically significant. In each column the vertical bar on it represents the standard deviation.  
Following, the results of P2 are displayed in Figure 14. The best results are related to the data gathered from configuration 1, followed by configuration 2 and 3. In this context, the results of statistical tests identify for configuration 1 has 8 different groups (a to h), and six groups (a to f) for configuration 2 and 3. Data from configuration 4 have been organised in six groups (a to f), as configuration 2 and 3. Nonetheless, data is more homogeneous, especially in the case of more concentrated samples. Thus, it is not possible to distinguish 17.5 g/L and 20 g/L and hard to distinguish between 10 g/L to 15 g/L. The standard deviations of all configurations are very low. The lowest standard deviation is found for configuration 1 with 0.018 g/L, followed by configuration 2 with 0.03 g/L. Configuration 3 and 4 are the cases with the highest standard deviation, 0.06 g/L and 0.04 g/L, respectively. In this case, the results point out that P1 has a lower deviation standard than P2. Furthermore, P1 is characterised by a higher number of groups in their configuration than P2.  
Figure 15 displays the results of the multiple range test for the four different configurations of P3. The best results are obtained for configurations 1 and 4. The data of both configurations are distributed in nine different groups (a to i). For configuration 2, we can identify seven groups (a to g). For configuration 2, the values of 0 g/L and 2.5 g/L, and 5 g/L and 7.5 g/L are the same. Meanwhile, eight groups (a to h) are formed with data of configuration 3. The standard deviation of this prototype is very low, lower than in other prototypes. The lowest values are obtained with data of configuration 4, 0.02 g/L. The highest standard deviation is linked to data of configuration 1, 0.03 g/L. Comparing the number of groups and their standard deviations, we can affirm that P3 is the prototype with better results.  
Figure 14: The graph presents a multi-range analysis for the four configurations where they are drawn by columns. Each column contains non-significant values between them. The different letters show that the values are statistically significant. In each column, the vertical bar on it represents the deviation.