The kinetics of the process of drying hot (80°C) and cold (20°C) candied pears were studied. The drying coefficient is found and an analytical dependence is derived for the drying time calculation. Experimental data of the change in the temperature of the thermal agent along with the height of the candied fruit layer was obtained.
In this paper, the dissolution kinetics of cement copper powder in sulfuric acid solutions containing cupric ions was examined. It was observed that the dissolution rate of copper increased with increasing the acid concentration, temperature, and stirring speed. It was determined that the dissolution rate of copper enhanced with increasing the cupric ion concentration up to 0.025 M. It was found that the temperature and concentration of cupric ion had more considerable effects on the dissolution of copper powder.
The kinetics of adsorption of ammonium ions under dynamic conditions has been studied. A mathematical model of the process was built. The mass transfer coefficient was calculated depending on the intensity of the change of location. It was established that ion exchange occurs in external and internal diffusion regions. The rate constants of ion exchange for the region of external and internal diffusion were calculated.
The dissolution process of potassium chloride particles in the apparatus with two-blade mechanical stirrer was investigated and the mass transfer coefficient was determined. The experimental results were generalized by criterion dependence. The independence of the mass transfer coefficient from the solid particles diameter was confirmed. A countercurrent process of potassium salt dissolution in two apparatuses with a mechanical stirring was considered. A mathematical model for countercurrent dissolution was developed and the efficiency of this process was determined.
The process of paraffin formation has been considered, including the peculiarities of the paraffin structure as a result of phase transitions with a decreasing temperature. Mathematical models for thermodynamic and kinetic calculations of the "solid-liquid" system phase equilibrium have been developed. To shift the "fuel oil-paraffin" balance towards the liquid, it is necessary to reduce the activity ratio of solid and liquid phases by introducing into the system a substance with a lower solubility parameter.
This study investigates the capability of Thuja occidentalis leaves carbon powder (TOLC) as a viable adsorbent for the expulsion of chromium(VI) from aqueous solutions. By batch mode, the removal percentage of Cr(VI) is observed to be pH perceptive and furthermore relies upon the time of equilibration, amount of the TOLC adsorbent and Cr(VI) concentration. TOLC adsorbent before and after adsorption of Cr(VI) was characterized with FTIR, SEM and EDX. Adsorption isotherm results divulge that the Langmuir model was a better fit.
The results of experimental studies of the peculiarities of metallization of granular polyethylene are presented. The influence of concentration factors on the metallization process of zinc-activated polyethylene granules of brand Liten PL-10 was investigated. It is established that by changing the concentration of copper sulfate and sodium hydroxide, as well as the degree of loading of polymeric raw materials, it is possible to effectively regulate the amount of recovered copper on granules of polyethylene, and therefore the thickness of the metal layer formed on them.
The kinetics of polymerization of 2-hydroxyethyl methacrylate with polyvinylpyrrolidone in a thin layer were studied. The dependences of the conversion for polymerization HEMA with PVP in mass and in solvent were determined. (Co)polymerization exotherms for the reaction in mass were calculated. The reaction order by initiator, monomer and polymer was determined and the mathematical dependence of the total rate of grafted copolymerization of HEMA to PVP was calculated.
The experimental investigation of the solubility of the prolonged-action nitroamophos obtained with the use of modified polyethylene terephthalate (PET) waste is presented. The kinetic coefficients of the diffusion process of the substances inside the shell are determined. The possibility of applying a theoretical model to predict the agro-ecological properties of encapsulated ammonium nitrate phosphate is demonstrated.
The influence of microwave radiation on the rate of СО2 uptake by chlorophyll-producing microalgae of the Chlorella Vulgaris has been established. Experimental dependencies of greenhouse gases absorption by microalgae depending on the impact of microwave electromagnetic (MEM) field have been obtained. The mathematical model of the dynamics of biomass growth of Chlorella Vulgaris microalgae depending on the time of electromagnetic radiation has been constructed.