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The data from the authors’ earlier investigations show that molecules of zinc dithiophosphate (ZDDP) added to a lubricant can absorb energy emitted by a solid surface, which is where triboreactions occur. If the lubricant contains structures able to conduct energy, the ZDDP reactions can occur even at a relatively large distance from the solid surface, which should increase the effectiveness of ZDDP as an antiwear additive. The purpose of this paper was to verify the thesis that the tribocatalytic effect depends on the ability of the solid surface to emit electrons/energy and the ability of ordered molecular structures, such as carbon nanotubes (CNTs), to conduct energy and, most likely, to enhance the energy transfer. The tribological tests were performed using a TRB3 tribotester for 100Cr6 steel balls and uncoated or a-C:H coated HS6-5-2C steel discs. Polyalphaolefin 8 (PAO8) and PAO8 mixed with ZDDP and CNTs were used as lubricants. The results of the tribological tests suggested that: (a) the effect of the interactions between ZDDP and CNTs was clearly visible; (b) the structure and properties of the solid surface layer had a significant influence on the antiwear action of the ZDDP additive.

This research reports and analyzes results of a field experiment started in 1984, when hard coal fly ash (HCFA) was added to soil at doses of 0 to 800 Mg·ha -1. During the first years of the experiment, traditional crops were grown in the plots, which in 1992 were converted into permanent grassland. Twenty-nine years after the application of fly ash, soil samples from the 0-20 cm soil layer were collected to determine chemical properties of soil. The results showed an elevated soil reaction, and high contents of available forms of P, K, and Mg, plus mineral forms of nitrogen and high soil organic matter. Under increased ash doses, analysed soils increased the C:N ratio and shares of N-NO 3 and N-NH 4 in total nitrogen content. These results justify that fly ash from combustion of hard coal in a power plant can produce long-term impact on soil, contributing to a certain improvement of its chemical, physical, and biological properties, which stimulate the sequestration of carbon in soil.

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Purpose -The purpose of this paper was to create conditions for the correct decision concerning an exchange of the used rope for a new one. A cognitive goal was to indicate the causes of its wear and determining its mechanism reliability and durability. Design/methodology/approach -The magnetic, organoleptic and strength standard tests of lifting triangle-strand ropes of a mining hoist were carried out. This way the current state of the tested rope was defined. Findings -On the basis of an analysis of the results of the performed tests: magnetic, organoleptic and fatigue tests, it can be said that the magnetic one is accurate enough only to indicate the place of the rope's biggest weakening, though the degree of weakening is not defined precisely -with significant excess. The accurate rope's destruction degree is indicated by the strength tests. Practical implications -The results of described investigations can improve safety of the mining rope mechanisms operation, even for an increased resource. Originality/value -The elementary wear processes, which are the basic reason for the destruction of the rope, are indicated. Rope destruction is caused mainly by tribological factors: abrasion, corrosion and fatigue wear. Magnetic tests are accurate enough only to indicate the place of the rope's biggest weakening (qualitative index). Most precisely, the rope's destruction degree (quantitative index) can be found by the strength tests.