## 4 Conclusions  
Density and viscosity of the binary systems DEG (1) + DMSO (2) and MDEA (1) + DMSO (2) were determined at temperatures between 293.15 to 313.15 K and atmospheric pressure. The calculated \(V^{E}\) values are negative for the DEG (1) + DMSO (2) system and positive for the MDEA (1) + DMSO (2) system, while the calculated \(\Delta\eta\) were negative for both systems. Models from Grunberg-Nissan, Heric-Brewer, Wilson, Noda-Ishida and Eyring-NRTL have been used to calculate viscosity coefficients and were compared with experimental data. The results showed that the Eyring-NRTL model is adequate to describe the viscosities of the binary mixtures. The activation energies of viscous flow were calculated. The values of \(\Delta\)G\({}^{\
eq}\) and \(\Delta\)H\({}^{\
eq}\) are positive for both binary systems and the values of \(\Delta\)S\({}^{\
eq}\) are positive for all compounds \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Parameters**} & \multicolumn{5}{c}{**T/(K)**} \\ \cline{3-7}
**Model** & **and \(\sigma\)** & **293.15** & **298.15** & **303.15** & **308.15** & **313.15** \\ \hline \(V^{E}/\)(cm\({}^{3}\cdot\)mol\({}^{-1}\)) & & & & & \\ DEG (1) + DMSO (2) & & & & & \\  & \(a_{0}\) & \(-0.736\) & \(-0.726\) & \(-0.701\) & \(-0.679\) & \(-0.668\) \\  & \(a_{1}\) & \(0.420\) & \(0.411\) & \(0.339\) & \(0.287\) & \(0.280\) \\ Redlich-Kister & \(a_{2}\) & \(0.157\) & \(0.296\) & \(0.319\) & \(0.379\) & \(0.453\) \\  & \(a_{3}\) & \(-0.384\) & \(-0.422\) & \(-0.328\) & \(-0.307\) & \(-0.198\) \\  & \(10^{3}\cdot\sigma\) & \(3.0\) & \(3.5\) & \(2.7\) & \(3.7\) & \(2.4\) \\ \cline{2-7}  & \(A_{0}\) & \(-0.785\) & \(-0.821\) & \(-0.805\) & \(-0.803\) & \(-0.817\) \\ Hwang & \(A_{1}\) & \(0.545\) & \(0.703\) & \(0.689\) & \(0.717\) & \(0.853\) \\  & \(A_{2}\) & \(-0.139\) & \(0.071\) & \(0.150\) & \(0.285\) & \(0.348\) \\  & \(10^{3}\cdot\sigma\) & \(7.4\) & \(8.0\) & \(6.3\) & \(6.3\) & \(4.4\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Polynomial coefficients \({}^{1}\) and standard deviations (\(\sigma\)) for the binary systems in the temperature range from 293.15 to 313.15 K.  
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Parameters**} & \multicolumn{5}{c}{**T/(K)**} \\
**Model** & **and \(\sigma\)** & **293.15** & **298.15** & **303.15** & **308.15** & **313.15** \\ \hline  & \(B_{0}\) & \(-\)0.730 & \(-\)0.720 & \(-\)0.708 & \(-\)0.680 & \(-\)0.666 \\  & \(B_{1}\) & \(-\)0.391 & \(-\)0.343 & \(-\)0.003 & \(-\)0.141 & 0.004 \\ Myers and Scott & \(B_{2}\) & \(-\)0.240 & 0.105 & \(-\)0.394 & 0.137 & 0.518 \\  & \(C_{0}\) & 1.122 & 1.060 & 0.556 & 0.654 & 0.410 \\  & \(C_{1}\) & 1.001 & 0.693 & 1.488 & 0.680 & 0.018 \\  & \(10^{3}\).\(\sigma\) & 2.9 & 3.3 & 2.0 & 3.9 & 2.6 \\ MDEA (1) + DMSO (2) & \(a_{0}\) & 1.436 & 1.403 & 1.364 & 1.307 & 1.259 \\  & \(a_{1}\) & 0.164 & 0.188 & 0.211 & 0.268 & 0.315 \\ Redlich-Kister & \(a_{2}\) & \(-\)0.274 & \(-\)0.307 & \(-\)0.359 & \(-\)0.411 & \(-\)0.520 \\  & \(a_{3}\) & 0.208 & 0.250 & 0.240 & 0.264 & 0.281 \\  & \(10^{3}\).\(\sigma\) & 5.1 & 5.3 & 8.4 & 10.0 & 10.4 \\ \cline{2-6}  & \(A_{0}\) & 1.527 & 1.505 & 1.483 & 1.444 & 1.432 \\ Hwang & \(A_{1}\) & \(-\)0.084 & \(-\)0.083 & \(-\)0.129 & \(-\)0.120 & \(-\)0.202 \\  & \(A_{2}\) & \(-\)0.647 & \(-\)0.737 & \(-\)0.830 & \(-\)0.977 & \(-\)1.186 \\  & \(10^{3}\).\(\sigma\) & 5.2 & 5.6 & 8.2 & 9.7 & 10.1 \\ \cline{2-6}  & \(B_{0}\) & 1.428 & 1.389 & 1.348 & 1.287 & 1.234 \\  & \(B_{1}\) & \(-\)0.387 & \(-\)0.586 & \(-\)0.466 & \(-\)0.425 & \(-\)0.313 \\ Myers and Scott & \(B_{2}\) & \(-\)1.759 & \(-\)1.874 & \(-\)1.742 & \(-\)1.836 & \(-\)1.788 \\  & \(C_{0}\) & \(-\)0.394 & \(-\)0.573 & \(-\)0.522 & \(-\)0.545 & \(-\)0.519 \\  & \(C_{1}\) & \(-\)1.078 & \(-\)1.152 & \(-\)1.073 & \(-