Fire-Retardant Plastering Mortars Based on Exfoliated Vermiculite and Volcanic Ash

The research results on the development of fire-retardant composite cement mortar mixtures on exfoliated vermiculite and volcanic ash with the use of a multifunctional additive are presented D-5. Compositions of fire-retardant composite mortars, which make it possible to significantly improve the physical and mechanical properties of mortar mixtures and mortars, are proposed. Introduction of a multifunctional supplement D-5 in mortar mixtures makes it possible to improve the composite mortar mixtures properties and improve the solution characteristics. Replacement of finely dispersed fraction of exfoliated vermiculite d<0,63 mm volcanic ash by volume in mortar mixtures does not cause a noticeable increase in the solution density, while their strength characteristics increase. The developed composite mortar mixtures meet the requirements of GOST 28013–98 and have a low-cost price due to volcanic ash use.

Analysis of Temperature Regulation, Concentration, and Stirring Time at Atmospheric Pressure to Increase Density Precision of Alginate Solution

Alginate is a high soluble organic linear polysaccharide polymer with adjustable density and viscosity. These unique properties have promoted Alginate uses widely in both food and non-food industries. Similar to other natural polysaccharides solution, alginate solution density is generally influenced by concentration, temperature and stirring time. Hence, this study aims to increasing the density precision of the alginate solution by setting temperature (30, 45, 60 and 75°C), alginate concentration (1, 2, 3, 4 and 5% mass) and stirring time (15, 30, 45 and 60 minutes) using the pycnometric method. The results showed that the higher temperature, the density would decrease, conversely, the higher of concentration and stirring time, the density of the alginate solution would increase. Therefore, it can be concluded if you want a density of 0.9228 g/ml alginate solution, the concentration of alginate used is 2% with a temperature of 30°C and a stirring time of 30 minutes

Control of chemically-driven convective dissolution by differential diffusion effects

&lt;p&gt;We numerically study the effect of differential diffusion in chemically-driven convective dissolution that can occur upon the reaction of a dissolving species A in a host phase when the chemical reaction destabilizes an otherwise stable density stratification. For example, an A+B&amp;#8594;C reaction is known to trigger such convection when, upon dissolution into the host solution, A reacts with B present in the solution to produce C if the difference between C and B in the contribution to the solution density is above a critical threshold. We show that differential diffusivities impact the convective dynamics substantially giving rise to additional convective effects below the reaction front, where C is generated. More specifically, we show that below the reaction front either double-diffusive or diffusive-layer convection can arise, modifying the local Rayleigh-Taylor instability. When B diffuses faster than C, a double-diffusive instability can develop below the reaction front, accelerating the convective dynamics and conversely, when B diffuses slower than C, diffusive-layer convection modes stabilize the dynamics compared to the equal diffusivity case. Our results are relevant for various geological applications or engineering set-ups that involve non-reactive stable density stratifications where transport can be enhanced by reaction-induced convection.&lt;/p&gt;

Densities for Ternary System of CaCl2–H2O–CO2 at Elevated P-T: An Experimental and Modeling Approach

Very few thermodynamic models exist for estimation of density alteration due to solution of CO2 in a pure H2O and CaCl2–H2O system. All of these models require density of CaCl2 solution to estimate density of CaCl2–H2O–CO2 system. Similarly, models presented to calculate CaCl2 solution density need pure H2O density in advance. The main approach to model density of CaCl2–H2O–CO2 system is based on estimation of density alteration of CaCl2–H2O system due to the solution of CO2 mole fraction. Hence, to estimate CO2–CaCl2–H2O system density, density of CaCl2 solution is necessary, and to estimate density of CaCl2–H2O system, density of pure H2O is required in advance. Firstly in this paper, density of 0, 1.91, and 4.85 mol/kg CaCl2 solutions saturated with CO2 at 328.15 to 375.15 °K and 68.9 to 206.8 Bar were measured through laboratory experiments. Then, a new model is developed to estimate the density of CaCl2 solutions containing CO2 based on the experiments conducted in this study. The average and maximum absolute deviations of the new model from the experimental data are 0.0047 and 0.0177, respectively. Hence, the new model combined with other existing models to separately calculate density of the CaCl2 solution can be used to accurately predict density of the CaCl2–H2O–CO2 system in a wide range of P-T applicable for subsurface reservoirs.