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This study describes the Casson (a non-Newtonian fluid) nanofluid bioconvection flow across a spinning disc in the presence of gyrotactic microorganisms, many slips and thermal radiation. Also, the flow is considered as a reversible flow. The esterification process is taken into account. Using the proper variables, a system of extremely nonlinear PDEs is converted into a system of ODEs. To arrive to the solution of such equations, a numerical approach is used. Using the bvp4c approach, nonlinear flow equations can be numerically solved. Investigated are the effects of different numbers on the thermal field, volumetric concentration of nanoparticles and microbiological field. The key characteristics of the parameters in relation to the profiles of the velocity, temperature, concentration and microorganisms are graphically assessed with appropriate physical effects. A graphical explanation is provided for the wall shear stress, local Nusselt number, local Sherwood number and local motile density number. Rate of motile density number shows a prominent difference between reversible and irreversible flows for Brownian motion and Peclet number. The results of the theoretical simulations have dynamic applications in the fields of biotechnology and thermal engineering.

In this study, an attempt has been made to synthesize esteramide quat by esterification of palm fatty acids with 1(2-hydroxyethyl piperazine) followed by quaternization with dimethyl sulphate (DMS). The optimum reaction conditions for esterification of palm fatty acids and 1(2-hydroxyethyl piperazine) were found to be 170°C reaction temperature and 150 mmHg pressure. The obtained esteramide was subjected to quaternization with different molar ratios of DMS. The consequences revealed that esteramide to DMS ratio of 1 : 0.95 and duration of quaternization for 2 h yielded esteramide quat of maximum cationic content, i.e., 64.9%. The instrumental analysis, viz. FT-IR, ¹H NMR, ¹³C NMR verified the esterification and subsequent quaternization of the obtained esteramide quat. Furthermore, the surface-active and performance properties of synthesized esteramide quat were also evaluated.

Mesoporous carbons prepared using a templating method under different carbonization temperatures are sulfonated with concentrated H₂SO₄. Without the moving of silica template carbon–silica composites were prepared, which can maintain the pore structure well during sulfonation reaction process. The resultant samples are characterized using nitrogen adsorption, transmission electron microscope, field-emission scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, and elemental analysis techniques. The catalytic performances of the sulfonated carbons and composites are evaluated by esterification reaction of methanol with acetic acid. The results show that a low-temperature carbonization process is favorable for improving the reaction conversion of acetic acid. In addition, the sulfonated carbon–silica composites show a higher acetic acid conversion than the sulfonated mesoporous carbons.

Due to its mechanical properties and ease of use, vinyl ester resin is enjoying increasing consideration. This resin normally is produced by reaction between epoxy resin and unsaturated carboxylic acid. In the present study, bis-phenol A based epoxy resin and methacrylic acid was used to produce vinyl ester resin. The reaction was conducted under both stoichiometric and non-stoichiometric conditions in the presence of triphenylphosphine as catalyst. The stoichiometric and non-stoichiometric experiments were conducted at 95, 100, 105 and 110°C and at 90 and 95°C respectively. The first order rate equation and mechanism based rate equation were examined. Parameters are evaluated by least square method. A comparison of mechanism based rate equation and experimental data show an excellent agreement. Finally, Arrhenius equation and activation energy were presented.