A two-parameter continuation method was developed and shown in the form of an example, allowing determination of Hopf bifurcation sets in a chemical reactor model. Exemplary calculations were made for the continuous stirred tank reactor model (CSTR). The set of HB points limiting the range of oscillation in the reactor was determined. The results were confirmed on the bifurcation diagram of steady states and on time charts. The method is universal and can be used for various models of chemical reactors.

The use of ammonium nitrate due to its high nitrogen content (> 26%) has made it the most utilized fertilizer in agricultural areas. However, being easily accessible with this feature encouraged its use for different purposes. Ammonium nitrate is usually produced with large tonnage (> 50 ton/h) and high cost (> $20 million) production processes. Therefore, any changes that can be made in the process must be applied in the process so that the result can be achieved easily without increasing the cost in any way. In this study, it is aimed to reduce the explosion sensitivity of ammonium nitrate used for explosive purposes in terrorist attacks. Thus, it was aimed to solve the problem by adding various chemicals to the ammonium nitrate production process so that it can only be used for agricultural purposes. For this purpose, the production process was examined by adding carboxymethyl cellulose and polyethylene glycol to the ammonium nitrate production process and the accuracy of the results was tested by instrumental analysis methods.

The article presents an experimental investigation of the rheological properties of carbomer microgels. All of the tested fluids were made up from commercial polyacrylic acid, Carbopol Ultrez 30. In total, eighteen microgels were prepared, differing in concentration; 0.2, 0.4 and 0.6 wt%, with six levels of neutralisation for pH from 4.0 to 9.0. Based on the experimental flow curves it was found that all tested microgels are yield stress shear-thinning fluids. Therefore, the Herschel–Bulkley model was used and its rheological parameters were determined. It was found that both the concentration and the pH value significantly affected the yield stress. As the Carbopol concentration increased, the yield point also increased. With the increasing value of pH, the yield stress first increased until a certain maximum level and then decreased. The maximum values of yield stress were obtained for pH = 6 to 7, depending on polymer concentration. It was also found that flow curves of the tested microgels could be described using one universal master curve, thus they have common rheological behaviour.

The cyclic Electrothermal Temperature Swing Adsorption (ETSA) process in a fixed-bed column with Supersorbon K40 activated carbon (AC) was applied to remove propan-2-ol (IPA) from air. The bed was electrothermally regenerated using direct resistive heating method. The tests were performed in the range of operating parameters: IPA loading 0.18-0.26 kg/kg, voltage 19.5 V, set-point temperature 393–403 K, nitrogen flow rate 0.12 m3/h.

The analysis revealed, that raising the bed temperature resulted in an increase of desorption degree of adsorbate, reduction of regeneration time and an increase in the energy consumption. The application of insulation enabled reduction of energy consumption and regeneration time by 27% and 10%, respectively.

Greenhouse gases such as carbon dioxide and water vapour can be captured from gas streams on a zeolite 13X adsorbent. Experimental water vapour adsorption isotherms and kinetic curves were measured in the temperature range of 293–393 K and pressure up to 2100 Pa. The equilibrium data were developed with Toth and Sips multi-temperature isotherm models. The results of the process rate studies were described using pseudo-first and pseudo-second order kinetic models. Findings were compared with our own results of CO2 adsorption studies on the same zeolite.

The paper presents a comparative analysis to determine the optimal temperatures and the activation energies for various origin endo-inulinases from Aspergillus niger. The parameters were estimated based on the literature of the activity curves vs. temperature for hydrolysis of inulin. It was assumed that both the hydrolysis reaction process and the deactivation process of endo-inulinase were first-order reactions by the enzyme concentration. A mathematical model describing the effect of temperature on endo-inulinases from Aspergillus niger activity was used. Based on the comparison analysis, values of the activation energies Ea were in the range from 23:53  3:20 kJ/mol to 50:66  3:61 kJ/mol, the deactivation energies Ed were in the range from 88:42  5:03 kJ/mol to 142:87  2:75 kJ/mol and the optimum temperatures Topt were obtained in the range from 317:12  0:83 K to 332:55  0:72 for endo-inulinase A. niger.