Solid State Phenomena Vol. 364

Abstract: The aim of the presented work is to study polymer ceramic-inorganic composites for electromagnetic radiation absorbing. Epoxy-based polymer composites modified with ceramic-inorganic graphite-ferromagnetic (CIGF) fillers were first obtained: silicon carbide, chromium oxide Cr₂O₃, graphite, humic substances and potassium titanate. As polymer matrix epoxy resin based on Epikote Resin MGS LR 285 and Epikure Curing Agent MGS LH 285 was studied. Primary research was directed to study humic substance, silicon carbide SiC, chromium oxide Cr₂O₃, graphite and potassium titanate nanoparticles introduction impact on polymer ceramic-inorganic composites strength and technological properties. Complex of technological and strength characteristics were researched and compositions with humic substances 0.5 wt%, a higher silicon carbide SiC – 10 wt% content were studied, while chromium oxide Cr₂O₃, graphite content in 5–25 % wt. range was optimized. Results shows, that addition of humic substances, silicon carbide SiC, chromium oxide Cr₂O₃, graphite and potassium titanate nanoparticles into the epoxy resin up to 20 wt% filler content increases the composite impact strength and breaking stress during bending. The CIGF fillers complex system using advantage is proven by studying the nature of modification effect on ceramic-ferromagnetic-graphite polymer composites for electromagnetic radiation absorption.

Abstract: Atmospheric air, which is a natural resource, significantly affects the health and disease level of the population [1, 2], as well as the quality of the environment [3, 4]. However, as a result of anthropogenic activity, the environmental condition of the air has a tendency of constant deterioration [5, 6]. The main anthropogenic source of atmospheric pollution is large industrial conglomerates, which include motor vehicles [7, 8]. Chemical pollution of the air on a global scale leads to the greenhouse effect, the appearance of acid rain [9, 10] and pollution of aquifers [11, 12], and as a result, an increase in diseases [13], pandemics [14]. The goal of the study is to investigate the relationship between the mechanical characteristics of polypropylene filter material and their deformation under external forces for stretching and determine the safe period of use of disposable respirators. Four types of samples have been used for experimental research. Operational properties were determined by three indicators: elongation from applied force, penetration coefficient by a test aerosol of paraffin oil, and air flow resistance in accordance with the requirements of the DSTU EN 149:2017 standard. The dependence of relative elongation on tensile force has been established for samples of Eleflen and Meltblown materials with an additional layer of coarse fiber material and without an additional layer. It has been shown that the presence of an additional layer increases the tensile force of the filter material sample by 1.5 times. It has been found that the longitudinal fibers of the filter material samples withstand 15 % more external force applied for stretching, allowing manufacturers to ensure the proper fit of respirator structural elements, which ensures a longer service life. Research results show that an additional layer of material increases the strength indicators of the main filter layer by 3 times. Scientific novelty lies in determining the relationship between the mechanical characteristics of polypropylene filter material for the production of disposable protective respirators and their protective properties and deformation under external forces by stretching. The practical value involves in determining the penetration coefficient, which ensures the appropriate protective efficiency of the respirator within the range of 0 to 10% elongation. The presence of an additional layer of coarse fiber material allows increasing this value based on the properties of the filter material (fiber thickness, packing density).

Abstract: An algorithm for predicting the intensity of sorption of gaseous materials released into the atmosphere as a result of an accident is proposed. The algorithm consists of three hierarchical levels: monitoring the parameters of gaseous material emission, predicting the consequences of gaseous material emission before and after sorption, and making a management decision. The first hierarchical level includes 4 blocks: obtaining information from the chemical reconnaissance group and the facility representative on the type, amount of hazardous gaseous materials, release intensity and scale of the accident; obtaining information from the hydrometeorological service on temperature, atmospheric pressure, wind direction and speed in the accident area; processing the information received; information on the availability of forces and means for sorption of hazardous gaseous materials. The second hierarchical level also includes 4 blocks: readiness of forces and means for sorption of hazardous gaseous materials; calculation with sorption; calculation without sorption; determination of the boundaries of the chemical damage zone according to the established criteria. At the third hierarchical level, there is 1 block: making a management decision. The software implementation of the proposed algorithm was carried out. The use of the developed algorithm and its software implementation will increase the speed and accuracy of predicting the consequences of the release of hazardous gaseous materials in an accident.

Abstract: The article presents the results of studies of the chemical stability of solidified radioactive waste with alkali cement through long-term leaching. Efficiency of application of alkaline slag Portland cement type LCEM IV as a matrix for reliable chemical and physical binding of caesium ions in the compound for long-term burial we confirmed. Modification of alkaline cement by additions of magnetite from 5 to 8.3% and zeolite in the amount from 4.2 to 5% promotes additional sorption of caesium ions in solidification products of alkaline matrix at maximum content of radioactive waste up to 17.5%. It they noted that the maximum values of sorption capacity of compounds (from 42000 to 68000 ml/g) we observed on the 14th day of the leaching process. They are characteristic for compounds containing magnetite from 5 to 8.3%, zeolite - from 4.2 to 7.5% and radioactive waste from 10 to 15%. It is shown that on the first day of leaching the highest rate (8.35E-02 g/сm²day) is characterised by compositions containing magnetite from 5 to 8.3%, zeolite from 4.2 to 5% and radioactive waste from 15 to 17.5%. At 56 days of the test, the leaching rate decreases exponentially to values of 3.45E-05 to 9.62E-06 g/сm²day. Characteristic of compounds, magnetite and zeolite up to 5% and radioactive waste 17.5%.