Butanol seems to be an eligible fuel for compensating for the increasing fuel consumption. Biobutanol could be produced from local sources in the place of use. Its properties show similar results to gasoline, so biobutanol could be added as a biocomponent into fuels. Important properties, in the case of blending biobutanol into gasoline, are its fluid properties and their dependence on the temperature. Therefore, in this paper, the volumetric mass density and viscosity of the selected ratios between biobutanol and gasoline (0, 5, 10, 85, 100 vol.%) were tested over the temperature range from −10 °C up to 40 °C. Gasolines with a 95 Research Octane Number (RON 95) and with a 98 Research Octane Number (RON 98) were used. It was observed that as the temperature increased, the viscosity and volumetric mass density of the samples decreased nonlinearly. Four mathematical models were used for modelling the viscosity. The accuracy of models was evaluated and compared according to the coefficient of determination R² and sum of squared estimate of errors (SSE). The results show that blends with 5 vol.% and 10 vol.% of biobutanol promise very similar fluid properties to pure gasoline. In contrast, a blend with 85 vol.% of biobutanol shows different fluid properties from gasoline, especially in negative temperatures, a lot. For practical applications, mathematical polynomial multivariate models were created. Using these models, three-dimensional graphs were constructed.

Liquid egg products are one of the basic raw materials for the food industry. Knowledge of their rheological and flow behaviour in real technical elements is absolutely necessary for the selection of suitable technological equipment for their processing. In this article, the rheological properties of liquid egg products were determined. Eggs from six different species of poultry are used: domestic hen (Gallus gallus domesticus) hybrid Hisex Brown; Japanese quail (Coturnix japonica); German carrier goose (Anser anser f. domestica); domestic ducks (Anas platyrhynchos f. domestica); domestic guinea fowl (Numida meleagris f. domestica); and domestic turkeys (Meleagris gallopavo f. domestica). Liquid egg products showed pseudoplastic behaviour in range of shear strain rates from 0.2 up to 200 s⁻¹ and at the temperature of 18 °C. Thus, the flow curves were constructed using the Ostwald-de Waele rheological model, with respect to the pseudoplastic behaviour of liquid egg products. According to the values of the coefficients of determination (R²), the sum of squared estimate of errors (SSE) and the root mean square error (RMSE), this model was appropriately chosen. Using the consistency coefficient K, the flow index n and the adjusted equations for the flow rate of technical and biological fluids in standard pipelines, the 3D velocity profiles of liquid egg products were successfully modelled. The values of the Reynolds number of the individual liquid egg products were calculated, and the type of flow was also determined. A turbulent flow has been detected for some liquid egg products.

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic

The effect of the passage of agricultural machinery on the soil is influenced by, for example, the inflation pressure in tyres. This article describes the effect of different tyre inflation pressures (200 and 100 kPa) on selected physical soil properties in the field experiment. The undisturbed...