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The present study is an attempt to examine the effect of biodiesel chemical structure on the diesel engine combustion properties and exhaust emissions. For this purpose, nine new types of oil (second generation) are used for producing biodiesel. Also, fatty acid profiles are determined by gas chromatography. Results show that Urtica biodiesel causes the highest soot emission (0.98 vol %) and the minimum NOx emission (460 ppm). A decrease in CN increases NOx and decreases soot emission at high engine loads. The longest chain is gained via Urtica biodiesel, and the increase of carbon chain length enhances soot emission. The increase of oxygen-to-carbon (O/C) ratio also affects the soot emissions and reduces the process (the O/C ratio is 0.1087 for Urtica). The increase of long-chain biodiesel fatty acids from C18 to C24 reduces the NOx emissions (C18−C24; 97.43 wt % for Urtica); moreover, there is a direct correlation between the increased carbon chain length and the amount of enthalpy. As the amount of unsaturated acids grows (94.93 wt % unsaturated fatty acids for Urtica), the value of the output soot is enhanced. Also, the increase in hydrogen-to-carbon ratio (1.8457 molar for Urtica) decreases the soot emissions. The increase in carbon chain length and decrease in O/C affect the HC and CO emissions; therefore, Urtica biodiesel had the maximum CO and HC emission (0.036 vol % and 6.11 ppm, respectively). In addition, the reduction of fuel consumption increased the NOx emission and reduced the HC, CO, and soot emission.

The nanoparticles of Cobalt ferrite are synthesized using polyethylene glycol as a solvent by the solvothermal method in a surfactant-free condition. Nanoparticles that were synthesized were determined by using various techniques such as Diffuse Reflection Spectroscopy (DRS), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive X-ray spectroscopy (EDAX). The Scanning electron microscope confirmed the range of spherical nanoparticles in the size of 20–33 nm. An excellent match was observed between the calculated particles size in the X-ray diffraction and electron microscopes results. Furthermore, their antimicrobial efficacy was determined by MIC, MBC, IC50 and disc diffusion method on Gram-negative ( Pseudomonas aeruginosa and Escherichia coli ) and Gram-positive ( Staphylococcus aureus, Bacillus cereus ) bacteria. The results indicated an acceptable bacteriostatic and bactericidal effects of this nanoparticles. Additionally, it was seen that by the increase in the concentration of nanoparticles, their antimicrobial property would increase. Background and objective In recent years, antibacterial materials have found a special place to avoid the overuse of antibiotics. In this study, the antibacterial effects of CoFe 2 O 4 nanoparticles on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus, were investigated due to their importance as human pathogens in nosocomial infection. Methodology In this study, the antibacterial effects of CoFe 2 O 4 nanoparticles such as MIC, MBC, IC50, and disc diffusion method were examined. Findings According to the results, CoFe 2 O 4 nanoparticles exhibited potent antibacterial activity against the bacteria that were examined, especially Bacillus cereus . The MBC (Minimum Bactericidal Concentration) of CoFe 2 O 4 nanoparticle on Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa , Bacillus cereus was between 0.12-0.48 mg/ml and MIC (Minimum Inhibition Concentration) on these bacteria detected between 0.06-0.24 mg/ml. The least IC50 determined for Bacillus cereus with a concentration of 0.061 mg/ml. Pseudomonas aeruginosa and Bacillus cereus identified as the most resistant and sensitive bacteria in the disc diffusion method, respectively.