## 2 Materials and Methods
### Physiological Characteristics of Biodiesel  
It was imperative to measure Moringa oleifera biodiesel (MOME) characteristics and their blends (MOB10 and MOB20) to assess the quality and suitability of these fuels for diesel engines. Each biodiesel has different physicochemical properties depending on feedstock type and biodiesel production process, post-production treatment, and fatty acid composition of the biodiesel. Hence, different biodiesel and biodiesel blends shows  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Specifications** \\ \hline Injector & Split type \\ Injection volume & 1 \(\mu\)L \\ Oven temperature & 210 \({}^{\circ}\)C, isothermal \\ Split flow & 100 mL/min \\ Carrier gas & Helium, 83 kPa \\ Column & 60 \({}^{\circ}\)C for the initial time \\ Column 2 flow & The constant flow of helium at 1 L/min \\ Temperature & Rise from 60 \({}^{\circ}\)C to 200 \({}^{\circ}\)C at an interval of 10 \({}^{\circ}\)C \\ Detector & 250 \({}^{\circ}\)C, flame ionization detector with electronic flow control \\ \hline \hline \end{tabular}
\end{table}
Table 1: Operating parameters of gas chromatography.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Fatty Acids** & **Chemical Structure** & **Molecular Mass (g/mol)** & **Composition of MOME (_w/w \%_)** \\ \hline Laurate & C12:0 & 214.34 & \\ Myristate & C14:0 & 242.4 & 0.1 \\ Palmitate & C16:0 & 270.45 & 8.1 \\ Palmitoleate & C16:1 & 268.43 & 1.6 \\ Stearate & C18:0 & 298.5 & 5.4 \\ Oleate & C18:1 & 296.49 & 74.3 \\ Linoleate & C18:2 & 294.47 & 4.1 \\ Linolenate & C18:3 & 292.46 & 0.2 \\ Arachidate & C20:0 & 326.56 & 2.3 \\ Eicosenoate & C20:1 & 324.24 & 1.5 \\ Behenate & C22:0 & 354.61 & 2.6 \\ Saturated & & & 18.7 \\ Monoussaturated & & & 76.9 \\ Polyunsaturated & & & 4.4 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Composition of moringa oleifera methyl ester.  
different effects on the CIDE's performance and exhaust emissions. In this study, the physicochemical properties (i.e., density, viscosity index, flash point, acid number, oxidation stability, pour point, cloud point, and CFPP and kinematic viscosity) of MOME and the blends were measured using ASTM standards. Results of the measured properties are summarized in Table 3. A Stabinger viscometer (Model: SVM 3000, [PERSON], UK) was utilized to measure density (at 15 and 40 \({}^{\circ}\)C) and kinematic viscosity (at 40 and 100 \({}^{\circ}\)C). A bomb calorimeter (Model: C2000 Basic, IKA, UK) was utilized for calorific value measurement.  
\[CCI=0.0892(T_{10N}) +45.2+[0.131+0.901\ (B)][T_{50N}]\] \[+[0.0523-0.420(B)][T_{90N}]+107(B)+60B^{2}\] \[+[0.00049]\big{[}T_{10N}{}^{2}-T_{90N}{}^{2}\big{]}\]  
where,  
CCI = calculated cetane index, D = density at 15 \({}^{\circ}\)C (g/mL), B = [e\({}^{(-3.5)(\text{DN})}]-1\), DN = D \(-\) 0.85, T\({}_{10N}\) = T\({}_{10}\)\(-\) 215, T\({}_{50N}\) = T\({}_{50}\)\(-\) 260, and T\({}_{90N}\) = T\(90\)\(-\) 310.  
The cetane index of MOME and the blends was calculated based on the recovered temperature values at 10%, 50%, and 90% (\(T_{10}\), \(T_{50}\), and \(T_{90}\)) and the fuel density at 15 \({}^{\circ}\)C (_D_) according to ASTM D4737 standard test methods, which is given by the equation in [41].