## 3 Results and Discussion
### Discussion
\begin{table}
\begin{tabular}{c c c c c c c c} \hline Test N. & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \\ \hline \(V\) (m/s) & 396.2 & 273.8 & 316.2 & 304.4 & 318.3 & 217.5 & 143.0 & 182.5 \\ \hline Test N. & 9 & 10 & 11 & 12 & 13 & 14 & 15 & 16 \\ \hline \(V\) (m/s) & 226.2 & 441.6 & 315.4 & 364.1 & 156.5 & 432.6 & 237.4 & 354.8 \\ \hline \end{tabular}
\end{table} 
Table 4: Results of water velocity in each test. Figure 9: Experimentally measured water front velocity versus distance. device in front of the IED, at least within this range of distances. In future work, this range of distances will be increased to identify the limits of this behavior. As a result of the previous factor selection, values of the adjusted R-squared and R-squared predictor of 92.50% and 85.78%, respectively, are obtained. In the Pareto diagram in Figure 10, the importance of each factor or interaction is observed, and the normal graph of standardized effects (Figure 11) indicates whether the factor or interaction positively or negatively affects the response: a fitted distribution line for effect values close to zero divides the graphic into two parts, so that the factors or interactions farthest away will be the most significant, with those that  
The outcomes of the hypothesis test show that the factors \"Explosive Specific Mass\" and \"Diameter\", and the interaction between \"Explosive Specific Mass\" and \"Density\", have a _p_-value \(<\) 0.05, so the null hypothesis is rejected and therefore it is accepted that there is a relationship between them and the response variable (water velocity). In other words, there is reliability in accepting its significance. The interaction between \"Diameter\" and \"Resistance Inner Tube\", with a _p_-value = 0.064 (which is close to the level of significance of 0.05) and with an _F_-value of 4.46, should not be ruled out, and it will be taken into account in future research. Figures 12 and 13 show the plots of the main effects and the most significant interactions. Figure 12 (left) represents the main effects plot for \"Diameter\" and \"Mass of Explosive\" effects. The better or worse fit of the factor line to the midline of the response is interpreted as a lesser or greater effect, respectively. The greater the slope, the greater the effect on the response variable. To analyze how the adjusted response of the two main factors is related, contour graphs are used (Figure 14), offering a two-dimensional view of the contour lines for the same response. The figure reveals how, at high levels of both variables, the velocity is high, and it is also possible to observe that with a small diameter or with little explosive, velocities of the order of 300-350 m/s can be achieved. Figure 11: Normal graph of standardized effects for a significance level \(\alpha\) = 0.05. Figure 12: **(Left)**: Main effects plot for the “Diameter” and “Mass of Explosive” effects. (Right): Interaction plot of “Mass of Explosive” and “Density”. It is clear that the greater the amount of explosive, the greater the energy and, also, with a smaller diameter of the device, the mass of water to be displaced will be less, which will translate into the superior speed of the water. However, the deactivator does not always wish to achieve the highest speed of the water front: this will depend on the target to be hit. In other words, the velocity needed will depend on the size, mass of the IED, and its construction characteristics, such as the impact resistance of its case (a backpack, a pot, a plastic bag, etc.). In fact, in previous works, such as the patent by [PERSON] [7], a device has been proposed that can hold up to three different amounts of explosive, depending on the effects that the deactivator wishes to achieve.