One-dimensional Modeling of Contaminant Migration in Unsaturated Porous Media with Dispersed Catalyst Particles

The relevance of the study is conditioned by the fact that increased consumption of synthetic polymers leads to an increase in environmental pollution due to the long decomposition time of plastic waste. As a result, it is necessary to develop polymer composites based on a biodegradable polymer matrix, and to improve the performance properties of finished plastic products, it is necessary to purposefully select cheap and affordable inorganic fillers. Thus, the purpose of this study is to investigate the regularities in the generation of a spatially structured polymer matrix under UV irradiation of polylactide-based composites filled with aluminosilicate microspheres (ASM). The leading approach to the given problem is to melt polymer composites of various compositions and to determine the physical, mechanical, and thermophysical characteristics of the prototypes, including the supermolecular structure of the polymer matrix under the influence of ultraviolet irradiation. The study suggests that the filling of polylactide with ASM particles leads to an increase in the elastic modulus, a decrease in the strength at static rupture and resistance to dynamic destructive effects, as well as heat resistance. Small aluminosilicate microspheres, when added to polylactide, perform the function of nucleation and, even with a small content, increase the crystallinity degree by 3.7 percentage points. In the range of ASM content from 1 pph to 10 pph, the absolute value of the crystallinity degree practically does not depend on the filler concentration in the polymer composite. UV (ultraviolet) irradiation in the presence of air oxygen initiates the thermooxidative destruction of polylactide and leads to the establishment of a spatially structured polymer phase using the electrostatic intermolecular interaction of additionally formed oxygen-containing functional groups in macrochains, as well as partial intermolecular crosslinking during recombination of macroradicals. The establishment of spatial structures in the polymer matrix under UV irradiation determines an increase in the resistance of experimental samples to thermal effects. It is manifested in an increase in the bending temperature under load by 7-10 percentage points, a decrease in the crystallinity degree by 1.2-2.6 percentage points, a decrease in the fluidity of the meltage and also an increase in the glass transition and melting temperature. The materials of the study are of practical value for the development of biodegradable composites based on polylactide filled with inorganic components.

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Features of application of the Lanchester-type mathematical models in stochastic formulation when assessing the realities of air-land battle

Semenenkо

Mashkin

Onofriichuk

et al. 2021

INCAS BULLETIN

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This study provides a brief overview of the application of possible modifications of Lanchester-type models, namely, the representation of differential equations of such models in stochastic form. The stochastic setting of differential levels is used in Dynamic models if it is necessary to take into account the influence of random fluctuations (in particular, in radio engineering, thermodynamics, population dynamics models, etc.). As for Lanchester-type models, their stochastic appearance would allow considering the influence of random factors and elements of uncertainty, which are present to a certain extent in any combat operations. At the same time, unlike deterministic models, the numerical solution of systems of stochastic differential equations in such models requires the use of special methods, the choice of a specific one may be based on the requirements for the need to obtain an unambiguous approximate solution, or the probability distribution of the desired quantities. The possibility of obtaining different types of solutions is due to a characteristic feature of the developed methods for numerical integration of stochastic differential equations, namely, the existence of weak and strong approximate methods for solving them. For Lanchester equations, as models for predicting the probable course and results of combat operations, it seems appropriate to obtain a solution precisely in the form of parameters for distributions of random variables, which is possible after processing the results of using weak numerical methods. In addition, such methods are considered easier to implement in practice. Of particular note are the issues of estimating the stability of solutions (in the sense of Lyapunov) of stochastic models. While for Lanchester-type models, approximate practical methods for estimating stability can be considered, especially in relation to the simplest, linear statements of basic equations. The study considers an example of using the stochastic Lanchester-type model based on a system of linear inhomogeneous differential equations, with assumptions about the stability of solutions to the stochastic formulation of such equations.

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One-dimensional Modeling of Contaminant Migration in Unsaturated Porous Media with Dispersed Catalyst Particles

Cited by 6 publications

References 20 publications

Modeling the One Class of Radionuclide Migration Processes in Soils under Non-Isothermal Conditions Using Perturbation Theory Methods

Modeling the One Class of Radionuclide Migration Processes in Soils under Non-Isothermal Conditions Using Perturbation Theory Methods

Development of a spatially structured polymeric matrix under UV irradiation of polylactide-based composites filled with aluminosilicate microspheres

Features of application of the Lanchester-type mathematical models in stochastic formulation when assessing the realities of air-land battle

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