## 3 Results and Discussion
(Note: Red dashed curves represent the best-fit curve for EME calculated by Equation (15) using actual weight, solid blue curves represent the best-fit curve for EMM/EPS mixtures calculated by Equation (15) using EME equivalent weight, and solid green curves represent the best-fit of experimental data). The value of SD at which a specified PPV of 20 mm/s is reached for individual explosives is determined from experimental PPV-SD data as illustrated in Figure 5. The best-fit equations for EMM/EPS explosives are obtained by the regression analysis of experimental PPV-SD data given in Figure 4. The results of the regression analysis are summarized in Table 7.  
From the best-fit line equations for individual explosives (Table 7), and with a PPV limit value of 20 mm/s taken from the standard, the SD is calculated according to the equation:  
\[SD=\left(\frac{PPV}{H}\right)^{\frac{1}{-\beta}} \tag{18}\]  
The results of the calculation are summarized in Table 7.  
As expected, the SD shifts to lower values (i.e., closer to the explosion point) with a decrease in detonation performance. From the known values of SD corresponding to PPV = 20 mm/s, one can calculate the maximum permitted weight of individual explosives at a specified distance from the blast point using Equation (2). The results of the calculation are given in Table 8.  
However, if experimental PPV-SD data are not available, one can apply the equivalency principle to estimate the maximum permitted weights at specified distances. This can be achieved in the following way: first, using the best-fit equation for reference explosive, the SD value at which the specified PPV value is reached is calculated using Equation (18). Then, from the known SD value (in this case for PPV = 20 mm/s, SD = 13.07 m/kg\({}^{1/2}\) for EME as reference explosive), the maximum permitted weight at a specified distance is calculated by \begin{table}
\begin{tabular}{c c c} \hline \hline
**Explosive** & **Best-Fit Line Equation** & **SD (PPV = 20 mm/s)** \\  & & **(m/kg\({}^{12}\))** \\ \hline EME & \(\begin{array}{c}PPV_{EMM}=395.64\text{-}SD_{W}^{-1.161}\\ \sigma=7.306\text{ mm/s},\text{r}=0.8357\end{array}\) & 13.07 \\ \hline EMM/EPS (50/50) & \(\begin{array}{c}PPV_{EMM/EPS}\text{ (50/50)}=112.72\text{-}SD^{-0.801}\\ \sigma=3.929\text{ mm/s},\text{r}=0.8014\end{array}\) & 8.65 \\ \hline EMM/EPS (40/60) & \(\begin{array}{c}PPV_{EMM/EPS}\text{ (40/60)}=276.25\text{-}SD^{-1.234}\\ \sigma=7.306\text{ mm/s},\text{r}=0.9439\end{array}\) & 8.40 \\ \hline EMM/EPS (30/70) & \(\begin{array}{c}PPV_{EMM/EPS}\text{ (30/70)}=135.14\text{-}SD^{-1.003}\\ \sigma=3.504\text{ mm/s},\text{r}=0.7448\end{array}\) & 6.76 \\ \hline EMM/EPS (20/80) & \(\begin{array}{c}PPV_{EMM/EPS}\text{ (20/20)}=74.68\text{-}SD^{-0.881}\\ \sigma=1.65\text{ mm/s},\text{r}=0.7751\end{array}\) & 4.46 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Best-fit line equations and scaled distance corresponding to PPV = 20 mm/s for studied explosives. Figure 5: Graphical presentation of determination of SD at which a specified PPV value is reached. Equation (2). Then, the maximum permitted weights of any other explosive can be calculated by Equation (3), applying the equivalency principle and knowing their EMEe. As visible from Table 8 and Figure 6, the weights predicted using the equivalency principle (WEP) are lower than those determined from the best-fit equation of experimental PPV-SD data. The difference between predicted and experimental PPV values goes from 17.6% for EMM/EPS-40/60 to 69.7% for EMM/EPS-20/80. In our opinion, there are two key reasons for such large differences. The first is generally a large scattering of measured PPV values, which could primarily be attributed to the small amount of explosive used in the experiment (15-42 g for EMM/EPS mixtures). The second reason lies in the fact that the PPV range in the experiments was significantly below the PPV limit value of 20 mm/s.