## 3 Results and Discussion
### Thermal Properties of Electro-Insulating Liquids Modified by Fullerene C\({}_{60}\)
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Property**} & \multirow{2}{*}{**Kind of Liquid**} & \multicolumn{4}{c}{**Temperature**} \\ \cline{3-6}  & & **25\({}^{\circ}\)C** & **40\({}^{\circ}\)C** & **60\({}^{\circ}\)C** & **80\({}^{\circ}\)C** \\ \hline \multirow{8}{*}{Thermal conductivity [W\(\cdot\)m\({}^{-1}\)\(\cdot\)K\({}^{-1}\)]} & MO & 0.133 & 0.130 & 0.128 & 0.126 \\  & MO + Span\({}^{\circledR}\) 20 & 0.133 & 0.131 & 0.128 & 0.126 \\  & MO + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 0.141 & 0.135 & 0.131 & 0.130 \\ \cline{2-6}  & SE & 0.158 & 0.156 & 0.153 & 0.151 \\  & SE + Span\({}^{\circledR}\) 20 & 0.158 & 0.156 & 0.153 & 0.152 \\  & SE + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 0.163 & 0.160 & 0.157 & 0.154 \\ \cline{2-6}  & NE & 0.182 & 0.180 & 0.178 & 0.175 \\  & NE + Span\({}^{\circledR}\) 20 & 0.182 & 0.180 & 0.179 & 0.175 \\  & NE + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 0.185 & 0.183 & 0.180 & 0.178 \\ \hline \multirow{8}{*}{Specific heat [W\(\cdot\)kg\({}^{-1}\)\(\cdot\)K\({}^{-1}\)]} & MO & 1902 & 1974 & 2077 & 2187 \\  & MO + Span\({}^{\circledR}\) 20 & 1961 & 2039 & 2149 & 2289 \\  & MO + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 1886 & 1955 & 2053 & 2159 \\ \cline{2-6}  & SE & 1905 & 1964 & 2052 & 2149 \\  & SE + Span\({}^{\circledR}\) 20 & 1937 & 1995 & 2082 & 2176 \\  & SE + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 1976 & 2031 & 2115 & 2207 \\ \cline{2-6}  & NE & 2028 & 2082 & 2166 & 2259 \\  & NE + Span\({}^{\circledR}\) 20 & 1983 & 2036 & 2118 & 2209 \\  & NE + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 1962 & 2011 & 2088 & 2174 \\ \hline \multirow{8}{*}{Kinematic viscosity [mm\({}^{2}\)\(\cdot\)s\({}^{-1}\)]} & MO & 17.1 & 9.6 & 5.4 & 3.4 \\  & MO + Span\({}^{\circledR}\) 20 & 17.6 & 9.9 & 5.8 & 3.6 \\  & MO + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 18.0 & 10.2 & 6.1 & 3.7 \\ \cline{2-6}  & SE & 55.1 & 28.3 & 14.0 & 8.1 \\  & SE + Span\({}^{\circledR}\) 20 & 55.7 & 28.6 & 14.7 & 8.3 \\  & SE + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 55.9 & 29.0 & 14.9 & 8.4 \\ \cline{2-6}  & NE & 56.3 & 32.7 & 18.3 & 11.5 \\  & NE + Span\({}^{\circledR}\) 20 & 56.5 & 32.7 & 18.3 & 11.5 \\  & NE + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 56.6 & 32.8 & 18.4 & 11.6 \\ \hline \multirow{8}{*}{Density [kg\(\cdot\)m\({}^{-3}\)]} & MO & 867 & 857 & 845 & 832 \\  & MO + Span\({}^{\circledR}\) 20 & 867 & 856 & 846 & 832 \\  & MO + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 868 & 858 & 846 & 832 \\ \cline{2-6}  & SE & 964 & 953 & 940 & 926 \\  & SE + Span\({}^{\circledR}\) 20 & 964 & 952 & 941 & 926 \\  & SE + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 965 & 954 & 941 & 926 \\ \cline{2-6}  & NE & 917 & 908 & 892 & 880 \\  & NE + Span\({}^{\circledR}\) 20 & 918 & 908 & 894 & 882 \\ \hline \multirow{8}{*}{Thermal expansion coefficient [K\({}^{-1}\)]} & MO & 0.00075 & 0.00076 & 0.00078 & 0.00080 \\  & MO + Span\({}^{\circledR}\) 20 & 0.00075 & 0.00077 & 0.00078 & 0.00081 \\ \cline{1-1}  & MO + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 0.00076 & 0.00077 & 0.00079 & 0.00081 \\ \cline{1-1} \cline{2-6}  & SE & 0.00076 & 0.00077 & 0.00078 & 0.00079 \\ \cline{1-1}  & SE + Span\({}^{\circledR}\) 20 & 0.00075 & 0.00076 & 0.00078 & 0.00079 \\ \cline{1-1} \cline{2-6}  & NE & 0.00074 & 0.00076 & 0.00078 & 0.00080 \\ \cline{1-1} \cline{2-6}  & NE + Span\({}^{\circledR}\) 20 & 0.00075 & 0.00077 & 0.00079 & 0.00080 \\ \cline{1-1} \cline{2-6}  & NE + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 0.00075 & 0.00078 & 0.00079 & 0.00081 \\ \cline{1-1} \cline{2-6}  & NE + Span\({}^{\circledR}\) 20 + TiO\({}_{2}\) & 0. Based on the obtained results, it was found that modifying the analyzed liquids with nanoparticles of titanium dioxide increases their viscosity in relation to the base liquids. The increase in viscosity is directly related to the addition of solid materials to the liquid. As in the previous case, this may result in a deterioration of the cooling efficiency.