COMPLEX DEFLOCCULENT BASED ON SODA, LIQUID GLASS AND OXYETHYLIDENEDIPHOSPHONIC ACID IN CERAMIC CASTING TECHNOLOGY

Here are discussed some results to use oxyethylidenediphosphonic acid (OEDPA) and various additives as a deflocculant composition for controlling the rheological properties of a ceramic suspension. According to the results of determining thixotropy, it was found that a complex thinner based on soda and OEDPA is the most effective. It is desirable to replace a portion of the soda with liquid glass. By the full factorial experiment method, it was established the optimal composition of the components of the complex thinner. The proposed thinner is highly effective in a wide range of OEDPA, soda, and liquid glass concentrations. The resulting suspensions have stable, high structural–mechanical properties. A mathematical model describing the effect of the composition of the thinner on the viscosity and thixotropy of the suspension is presented. The effect of the diluent on the mechanical properties of the molded dried and fired samples was determined. The addition of OEDPA to the thinner significantly lowers the rheological parameters and the rheological properties of the suspensions approach the rheological properties of Newtonian systems. It was found that OEDPA lowers the mass buildup rate, which can be increased by lowering the moisture content in the suspension, which makes it possible to increase the post-casting and -drying density of the samples. The introduction of this additive leads to an increase in the hydrate shell around the clayey particle and an increase in the stability of the suspension, but the increase in the ζ - potential in comparison with the production additive is very small. The mechanism of action of a complex additive is proposed, including ion-exchange, complexation and chemisorption. An increase in the strength and density of dry and calcinated clay samples as well as a decrease in the shrinkage and porosity are observed. The complex additive makes it possible to optimize the technology at the stages of casting slip and to decrease the number of parts rejected during molding, drying and firing.

CLASSIFICATION OF FODDER MASSES APPLIED TO ITS HYDRO-MECHANICS

The current stage in the development of agricultural production in livestock is characterized by the extensive use of pipeline transport to move the forage masses, which are related to non-Newtonian fluids. Production experience and scientific work on the study of hydrotransport systems showed that this method of transportation is the most economical and promising, it has high reliability of structural elements, improves sanitary and hygienic working conditions and makes it possible to fully automate the transportation process. The complex nature of the transportation of mixtures has not allowed to create a unified theory of hydrodynamic calculation of their parameters to date, therefore, various models are used for theoretical investigation of the nature of motion. To select a particular model, it is always important to correctly classify viscous semiliquid media with respect to hydrodynamics. Therefore, the article did not set out the specific goal of choosing a method for studying non-Newtonian systems, but solved the problem of their classification by known defining characteristics. The proposed classification does not pretend to be exhaustive in terms of the physical and chemical nature of the fluid, especially their combinations, but it covers almost all the anomalous phenomena that occur in the fluid during its transportation and helps to select a quantitative method for calculating the transporting fluid. The classification of non-Newtonian fluids with respect to their hydromechanics is based on the dependence of the shear stress on the shear gradient. For this dependence, each type of liquid is considered. The developed classification scheme further promotes a more complete account of the rheological properties of high-viscosity liquids during their transportation through pipes and facilitates the development of quantitative calculation methods.

Schwarzschild’s Spacetime

The concept of a metric is motivated and introduced, along with the introduction of relativistic quantities of spacetime, proper time, and Einstein’s field equations. Geodesics are cast in basic form as a Hamiltonian dynamical problem, which readers are guided towards exploring numerically themselves. The specific case of the Schwarzschild metric is presented, which is applicable to space around non-rotating black holes, and orbital motion around such objects is contrasted with that of Newtonian systems. Some well-known formulas for black hole phenomena are derived, such as those for light deflection (also known as gravitational lensing) and the innermost stable orbit, and their consequences discussed.

Influence of plasma on the physical properties of ointments with quercetin

Effects of two independent variables - the content of quercetin (0 or 1 or 1.5 or 5 %) and the content of plasma (0 or 2 or 4 or 6 %) - on the organoleptic properties and rheological parameters of model formulations prepared on an amphiphilic base were estimated. The consistency of all ointments was uniform, and the content of quercetin and plasma lay within the predefined range. Tested ointments are non-Newtonian systems. The content of quercetin and plasma was found to have a significant effect on the rheological properties of the ointments. An increase in the content of plasma in ointments was accompanied by a significant increase in their hardness, viscosity and shear stress and a reduction of their spreadability. The best rheological properties were shown by formulation F-3, containing 1.5 % of quercetin and 2 % of plasma.