## 3 Results and Analysis
### Temperature Variation Curves during the Elapsed Time  
Figure 6 is a group of graphs showing the surface temperature variation curves during the elapsed time of experimentation for ECM specimens mixed with SF compared to the PM specimen. As shown in Figure 6, each graph shows a constant trend with little variation in temperature compared to the initial temperature. In the case of the PM specimen as seen in Figure 6 and Table 5, the surface temperature reached 20.1 \({}^{\circ}\)C, 20.2 \({}^{\circ}\)C and 20.3 \({}^{\circ}\)C after 3600 s at applied voltages of 10 V, 20 V and 30 V, respectively. Regardless of the electrode spacing, an increase of 0.1-0.3 \({}^{\circ}\)C compared to the initial temperature (20 \({}^{\circ}\)C) was found, which indicates little temperature variation. In addition, even in the case of the ECM specimens mixed with SF as shown in Figure 6 and Table 5, for the same three applied voltages, the surface temperatures reached 20.2-20.6 \({}^{\circ}\)C, 20.3-21.2 \({}^{\circ}\)C and 20.4-21.8 \({}^{\circ}\)C, respectively, which represented increases of 0.2\(\sim\)0.6 \({}^{\circ}\)C, 0.3-1.2 \({}^{\circ}\)C and \begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline \multirow{2}{*}{**Designations**} & \multirow{2}{*}{\
\begin{tabular}{c} **Fiber** \\ **Type** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Fiber** \\ **Contents** \\ **(\%)** \\ \end{tabular} } & \multicolumn{6}{c}{**Maximum Heating Temperatures (\({}^{\circ}\)C)**} \\ \cline{3-10}  & & & **10 V** & & **20 V** & & **30 V** \\ \cline{3-10}  & & & **120 mm** & **40 mm** & **120 mm** & **40 mm** & **120 mm** & **40 mm** \\ \hline ECM-CF25 & & 0.25 & 20.6 & 21.8 & 24.9 & 34.3 & 30.1 & 77.0 \\ ECM-CF50 & & 0.50 & 20.7 & 22.3 & 27.0 & 37.5 & 31.3 & 79.6 \\ ECM-CF75 & CF & 0.75 & 21.3 & 25.4 & 40.9 & 48.4 & 42.6 & 88.1 \\ ECM- & & 1.00 & 23.4 & 27.7 & 41.1 & 51.4 & 54.8 & 140.5 \\ ECM- & & 1.25 & 23.3 & 34.8 & 46.5 & 73.7 & 65.9 & 145.1 \\ ECM-SF25 & & 0.25 & 20.2 & 20.2 & 20.3 & 20.3 & 20.4 & 20.4 \\ ECM-SF50 & & 0.50 & 20.2 & 20.2 & 20.3 & 20.3 & 20.5 & 20.5 \\ ECM-SF75 & SF & 0.75 & 20.3 & 20.3 & 20.5 & 20.6 & 20.8 & 20.9 \\ ECM- & & 1.00 & 20.4 & 20.5 & 20.7 & 20.8 & 21.1 & 21.3 \\ SF100 & & & & & & & & \\ ECM- & & 1.25 & 20.5 & 20.6 & 21.0 & 21.2 & 21.5 & 21.8 \\ SF125 & & & & & & & & \\ PM & - & - & 20.1 & 20.1 & 20.2 & 20.2 & 20.3 & 20.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The results of maximum heating temperature measurements for the specimens. Figure 5: Maximum heating temperatures of ECM specimens and PM specimen according to applied voltages: (**a**) 120 mm, and (**b**) 40 mm. 0.4-1.8 \({}^{\circ}\)C, respectively, compared to the initial temperature. The heating value was so insignificant that the surface temperature was similar to the ambient temperature. On the other hand, Figure 7 features graphs showing the surface temperature variation curves during the elapsed time of experimentation for ECM specimens mixed with CF compared to the PM specimen. In all graphs except for Figure 7a, the surface temperature increased gradually from the initial stage, showing a tendency of convergence to a certain value after reaching the maximum point. As shown in Figure 7a, the surface temperature of specimens reached 20.6-23.3 \({}^{\circ}\)C at an applied voltage of 10 V and an electrode spacing of 120 mm, which is an increase by 0.6-3.3 \({}^{\circ}\)C compared to the initial temperature, indicating that there was almost no temperature variation. According to Figure 7b, however, the surface temperature of specimens reached 21.8-34.8 \({}^{\circ}\)C at an applied voltage of 10 V and an electrode spacing of 40 mm, a 1.8-14.8 \({}^{\circ}\)C increase compared to the initial temperature.