The mechanism of formation of protective films on the steel surface in the course of its treatment by the extract of rapeseed (Brassicaceae family) cake regarded as a volatile corrosion inhibitor and its component composition are experimentally determined and theoretically substantiated. The dynamics of changes in the component composition of volatile compounds in the 2-propanol extract of rapeseed cake is studied by the methods of gas chromatography, mass spectrometry, and IR-spectroscopy. The influence of individual components on the corrosion behavior of steel under the conditions of periodic condensation of atmospheric moisture is investigated. It is shown that the main components of the 2-propanol extract responsible for its anticorrosion efficiency are aldehydes, ketones, and glycosides. A model of the structure of protective films is proposed.In the course of transportation and conservation, metal products are damaged by corrosion, which decreases their user and export values. Hence, it is necessary to guarantee their temporary anticorrosion protection in order to preserve their quality and the outward appearance of the surfaces under the atmospheric conditions [1,2]. In this case, the most efficient and (sometimes) the only possible method for the protection of metals is given by the volatile inhibitors. At present, the production of volatile inhibitors of the atmospheric corrosion is absent in the Ukraine and the domestic market is filled with extremely expensive imported products, sometimes of very low quality.Due to the insufficient supply of these inhibitors, the increase in the cost of raw materials used for their production, and a permanent strengthening of the sanitary-hygienic requirements to the means of corrosion protection, it is necessary to create new inhibiting compositions based on the natural resources. Thus, the organic compounds obtained from ecologically safe and annually renewed vegetable raw materials seem to be quite promising for the development of new volatile inhibitors of the atmospheric corrosion [3-6].In [7,8], it is shown that the wastes of the production of oil from rape seeds (Brassicaceae family) may serve as a source of natural organic compounds. Moreover, the chemical compositions of the volatile compounds of 2-propanol extract of rapeseed cake and the inhibiting efficiency of this extract were investigated. However, we do not know the compounds appearing in the composition of this extract and responsible for its inhibiting efficiency. Therefore, it is necessary to study the specific features of the mechanism of formation of protective films formed from the vapors of the extract of rapeseed cake on the steel surface and to determine the compositions of these components.
Purpose is to predict potentially hazardous effects of diesel vehicles of mining enterprises on the environment and to minimize the environmental risks caused by these impacts by modifying motor fuels with special additives. Methods. Method of mathematical modeling, implemented within the MathCAD environment, was used for assessment of the increase of environmental load on the roadside territories and human health caused by emissions of pollutants from exhaust gases of heavy diesel vehicles (HDV) of mining enterprises. The data, concerning potential emissions of the most hazardous pollutants from the exhaust gases of HDVs, has been generalized both by own field observations and by the analysis of scientific literary sources. The load on the environment by the analyzed pollutants has been corrected taking into consideration the share of heavy diesel vehicles engaged in cargo carriages by means of pendular routes of mining enterprises. Findings. Increased level of the environmental risk, resulted from operation of heavy diesel vehicles and other types of special-purpose diesel machines, has been identified. It has been proposed to apply a method of physical and chemical control of the motor fuel by adding multifunctional fuel composition (i.e. additive) containing both surface-active and antioxidant complexes. It has been determined that the use of the developed additive decreases substantially the load on the environment, in particular, on the roadwayby 26-29% for nitrogen oxides and by 39-41% for particulate matter (PM). The abovementioned mitigates environmental risks as well as the impact of heavy diesel vehicles on the human health. The substantial reduction of the distances, within which safe concentration levels of the analyzed pollutants can be observed, has been achieved. Originality. It has been identified that the diesel fuel modification by the developed additive makes it possible to solve a problem of local and diffuse pollution of a roadside space resulted from HDV emissions. It has been proved that the use of the fuel composition decreases toxic level of exhaust gases of diesel motors and reduces fuel consumption while improving the fuel burning conditions as well as air-fuel mixture forming. Practical implications. The obtained results may be applied to improve ecological safety level of the roadside territories and to minimize the ecological risks resulted from HDVs of mining enterprises for the environment and human health.
The physical-mechanical influence and chemical effect of calcium formate, vinyl acetate/versatate, and vinyl-acrylate copolymer on the processes of solidification, hardening, and structure formation of the cement matrix were studied during the research reported here. The compositions of mixtures containing additives in the amount of 1, 3, and 5 wt % were investigated. Noteworthy is the water-holding nature of vinyl acetate/versatate and vinyl-acrylate copolymer. With the introduction of appropriate additives, an increase in working time of the mixtures is noted, which was manifested in prolonging the end time of solidification duration. Calcium formate reduced the end time of solidification duration with an increase in the content of the additive. During 28 days of hardening, a decrease in strength gain was observed with an increase in the content of the additive compared to control samples. At 1 wt % of the additive, the decline in strength on day 28 was 8.7 % for calcium formate, 13 % for versatate, and 15.5 % for vinyl-acrylate copolymer. For versatate and vinyl acrylate with the addition of 3 and 5 wt % in the mixture, the loss of strength is 23–25 % and 27–56.7 %, respectively. 5 wt % calcium formate admixture, compared to 3 wt %, on day 7 and day 28 of hardening has a higher strength index. This nature of the effect of additives is explained by the formation of polymer structures throughout the volume of the mixture with the introduction of versatate and copolymer vinyl acrylate, as well as their chemical interaction with the components of the cement binder during hydration in the formed alkaline medium. Calcium formate plays the role of both a filler and a hardening accelerator due to the introduction of an additional amount of calcium ions. The reported results can be used as a basis for continuing to study the effect of redispersed additives on the durability of cement articles, the development of new formulations for building mixtures, and their potential use in the production of concrete.
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