Mental work, used everywhere at present, is quite diverse and is characterized by various degrees of responsibility, monotony, attention, and the level of emotional stress. To provide comfortable living conditions for a person in a permanent workplace, it is also necessary to organize air conditioning systems. The most promising for this activity are personal ventilation systems, which provide a high-quality air environment in the area of human breathing while reducing capital and operating costs in comparison with traditional (mixing, displacement ventilation). However, when designing personal ventilation systems, one should not focus on the “average reference man”, but take into account the individual characteristics of the employee (age, gender, etc.) performing a specific type of mental activity. In order to clarify the actual value of carbon dioxide (with a certain degree of error) emitted by a person in a certain mental work, we perform a series of experiments. The authors conducted a significant amount of full-scale experimental investigations, the result of which is the confirmation of nature and dynamics of carbon dioxide`s changes in the room in the absence (inactivity) of ventilation systems (linear dependence), as well as the refinement of the amount of carbon dioxide emitted in a particular type of mental activity. It should be noted that this work is the beginning of large-scale scientific research designed to collect and systematize data on emissions of harmful substances from people engaged in various types of mental activity.

Great opportunities for increasing the resource of parts of agricultural machinery that require restoration are opened up by technologies for applying hardening coatings. Options for obtaining galvanic deposits in various electrolytes, which allow depositing metal coatings with various special properties that ensure reliable operation of restored units under appropriate conditions, are considered in the article. Solutions of sulphate, chloride, and hydroboric fluoride salts of divalent iron were used as the electrolyte. Methods of chemical analysis of galvanic deposits were used. The hardness of the deposited layers was determined using a PMT-3 instrument. The effect of various alloying additives on the quality of the precipitates obtained is analyzed depending on the concentration of inclusions. The boundaries of inclusion concentrations are determined. It has been established that for controlled deposition of a composite coating, the concentration of inclusions in the deposited iron-containing coating should not exceed 20 g/l. It has been found that even an insignificant presence of manganese inclusions in an iron-based composite coating, which is of the order of the measurement error, doubles its hardness. The dependence of the concentration of ammonium chloride, as the base material for the extraction of pure manganese, on the hardness of the deposited galvanic precipitate, was studied in the framework of the described study. The highest hardness was achieved at a concentration of NH4Cl in the range of 100–150 g/l, and manganese - 0.4% by weight. Graphical dependences of the main quality indicators of the resulting coatings on the type and composition of the electrolytes used were obtained. The influence of the electrolyte temperature and electrolysis regimes on the hardness of the deposited metal is analyzed.

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