The review of foreign studies devoted to the utilization of polymeric composite materials (PCM) by the solvolysis method is presented. It has been established on the basis of this that two groups of technologies predominate: directed to fiber extraction by destruction of the organic matrix and based on partial destruction of individual bonds while preserving valuable matrix components. The results of experimental studies on the selection of reagents for the recovery of carbon fiber from phenol formaldehyde PCM are presented. The characteristics of the change in the properties of the secondary fiber on the basis of a visual assessment are given, showing the appearance of roughness and irregularities in the fiber swirl and a significant decrease in their thickness. The results of research on fine-dispersed reinforcement of concrete with secondary carbon fiber, which showed an increase in flexural strength by 3–8 %, are described. The problem of dispersion of secondary carbon fiber during its introduction into concrete is considered.

The article addresses the modeling of the process of manufacturing a large-sized shell, given the thermomechanical behavior and viscoelasticity of the composite mandrel. The results of the experimental identification of viscoelasticity parameters of the examined material are presented. A numerical algorithm for adapting the experimental data for the ANSYS Mechanical APDL finite element analysis package is proposed. A Prony series expansion of the relaxation kernel is used as a model for describing the material behavior. The effect of temperature on the rate of relaxation processes is taken into account through the application of a temperature-time analogy according to the Williams–Landel–Ferry formula. The selected model with the calculated parameters was implanted into the commercial package of ANSYS Mechanical APDL. Simulation of two process steps of manufacturing a large-sized product was performed: winding and heat treatment of the shell. For this purpose, the quasistatic problem of mechanics and unsteady thermal conduction under conditions of convective heat transfer were solved by the finite element method. The influence of thermomechanical behavior of the mandrel material on the normal pressure acting on the mandrel surface as a function of temperature and force factors was estimated quantitatively and qualitatively. It was found that with respect to the nonlinear behavior of the composite material, the pressure level decreases by 50% compared to the case of using models of elastic behavior. This result justifies the importance of using complex models of material behavior in studying long-term technological processes, especially those associated with high-temperature effects.

Field and laboratory studies of the composition and properties of solid municipal waste have been performed, on the basis of which the quantity and quality of the recovered secondary raw materials and "tailings" of sorting, which are used as energy fraction or solid fuel from waste, are simulated. The elemental composition for dry ashless (combustible) mass for all considered variants of solid fuelcomposition from wastes is calculated. Presented is the ratio C: O and heat of combustion on a dry basis for different versions of solid fuel composition from waste. For comparison, the C: O ratio is shown for various components of solid fuel from waste: for synthetic materials (polymers, rubber) and for biodegradable materials (organic waste, waste paper, wood).

The paper discusses the key stages of developing an integrated methodology for predicting the stress-strain state of a sand-polymer mandrel-plastic shell system during heat treatment with the adaptation of experimentally determined viscoelastic characteristics of components in the CAE ANSYS Mechanical APDL package. The first stage solves the problem of determining the effective viscoelastic characteristics for the shell. Viscoelastic characteristics are determined on the basis of the developed complex experimental calculation method based on the solution of boundary quasistatic problems of thermomechanics on a representative volume at two scale levels. The results obtained in this work, based on experimental data and developed numerical methods for determining the thermo-viscoelastic characteristics of composites, make it possible to estimate the contribution of stress relaxation in the mandrel and the shell to the evolution of the stress-strain state in the process of manufacturing the shell. Also, the developed technique makes it possible to predict the appearance of technological defects and determine the stages of heat treatment at which these defects occur.

A methodology for the ecological assessment of technologies for municipal solid waste (MSW) processing and solid recovered fuel (SRF) production is proposed, including calculations of direct, indirect and prevented greenhouse gas emissions at all stages of waste management, taking into account the composition of the waste, the properties of the individual components of the MSW and the characteristics of used equipment. The elemental balance of fossil and biogenic carbon was calculated for MSW management system. It is concluded that MSW processing with recyclables recovery and SRF production can reduce greenhouse gases release from 5.8 to 67.6 % with respect to waste disposal at the MSW landfill.