Можливості використання твердих тонких покриттів у HCR зачепленні, яке працює в екологічно чистому мастилі

The article describes the possibilities of application of hard thin coatings to a non-standard involute HCR gearing, made from 16MnCr5, working in interaction with ecological transmission oil OMV Biogear S150. Based on an analysis of their geometric characteristics and their differences from nonstandard C–C teeth, the possibilities of applying thin hard coatings to the side surface of the teeth are assessed. From the previous results obtained at the research center (UDTK sjF STU in Bratislava), the nitride TiALCN was applied and the article presents the results obtained on the Niemann´s stand for scuffing, from which it follows that due to the higher heights of the tooth addendum (hа = 1,2m) compared to the standard (hа = 1,0 m) and hence larger meridians, the greatest damage there was on an addendum of pinion.У статті описані можливості застосування твердих тонких покриттів до нестандартної евольвентної передачі HCR, яка виготовленна з матеріалу 16MnCr5 і працює в екологічно чистому трансмісійному мастилі OMV Biogear S150. На основі аналізу їх геометричних характеристик і відмінностей від нестандартного зубчастого зачеплення C–C оцінюються можливості нанесення тонких твердих покриттів на бічну поверхню зубів. З попередніх результатів, отриманих в дослідницькому центрі (UDTK sjF STU в Братиславі), застосований нітрид TiALCN і в статті представлені результати, отримані на стенді Ньюмана для зносу, з яких випливає, що через більшу висоту головки зуба (hа = 1,2m) порівняно зі стандартною (hа = 1,0m) і, відтак, великими меридіанами, найбільший знос був на голівці зуба шестерні

Effective antioxidant phenolic compounds in selected varieties of apples

Polyphenolic compounds are effective antioxidant regarding their ability to reat with free radicals of fatty acid and oxygen(free radical scavening effect). One of the richest source of polyphenolic compounds in human nutrition are apples (Malus Mill.). Our work was focused on determinaton of total polyphenols contents and antioxidant activity and evaluate the presence of dislocation active antioxidant components in four of selected varieties of apples Idared, Jonagold, Pinova, Topaz (peel extract and pulp extract).The total contents of phenolic compounds,determined according to the Folin-Ciocalteu reagent spectrofotometric by Lachman and antioxidant activity was measured using a free radical used in this study was 2,2-diphenyl-1-picrylhydrazyl (DPPH). Average content of total polyphenols in selected varieties of apples was 622,67 mg.kg-1 (peel extract) and 568,7mg.kg-1 (pulp etract) after harvesting. Relationships between content of total polyphenols and antioxidant activity is affected by varietal difrences

Spectral and orbital survey of medium-sized meteoroids

We investigate the spectra, material properties, and orbital distribution of millimeter- to decimeter-sized meteoroids. Our study aims to distinguish the characteristics of populations of differently sized meteoroids and reveal the heterogeneity of identified meteoroid streams. We verify the surprisingly large ratio of pure iron meteoroids on asteroidal orbits detected among mm-sized bodies. Emission spectra and multi-station meteor trajectories were collected within the AMOS network observations. The sample is based on 202 meteors of -1 to -14 magnitude, corresponding to meteoroids of mm to dm sizes. Meteoroid composition is studied by relative intensity ratios of Na, Mg, and Fe. Heliocentric orbits, trajectory parameters, and material strengths inferred from empirical $K_B$ and $P_E$ parameters were determined for 146 meteoroids. An overall increase of Na content compared to the population of mm-sized meteoroids was detected, reflecting weaker effects of space weathering processes on larger meteoroids. We report a very low ratio of pure iron meteoroids and the discovery of a new spectral group of Fe-rich meteors. The majority of meteoroids on asteroidal orbits were found to be chondritic. Thermal processes causing Na depletion and physical processes resulting in Na-rich spectra are described and linked to characteristically increased material strengths. Numerous major and minor shower meteors were identified in our sample, revealing various degrees of heterogeneity within Halley-type, ecliptical, and sungrazing meteoroid streams. Our results imply a scattered composition of the fragments of comet 2P/Encke and 109P/Swift-Tuttle. The largest disparities were detected within the $\alpha$-Capricornids and $\delta$-Aquarids. We also find a spectral similarity between $\kappa$-Cygnids and Taurids, which could imply a similar composition of the parent objects of the two streams

POSSIBILITIES OF USING THE ECOLOGICAL OIL ARNICA S 46 IN AGRICULTURAL ENGINEERING

This paper deals with a possible use of biodegradable oil for lubrication of tribological nodes in hydraulic and transmission systems. They are mainly used in agriculture and forestry. For this reason, the research project was aimed mostly at hydraulic and gear oils, directly or indirectly designated for machinery working in these fields. The oil was tested according to the standard ASTM G77-05(2010). The study of the tribological node included monitoring the friction factor depending on time, and monitoring the temperature of the sliding node depending on time. In the triboelement shaft – bearing, we monitored the weight losses as well as changes in the selected characteristic of contact surface roughness. The monitored characteristic was Ra. A complete picture of geometric changes of the tested triboelement was described by the geometric deviation of cylindricity. The system also includes the study of lubricating medium. We determined the initial and final code of oil purity. The characteristics were statistically evaluated. Two oils were tested: PP 80 (producer: Slovnaft Bratislava) and ARNICA S 46 (producer: Agip). According to the results, both oils are appropriate for using in given conditions. No significant differences in their tribological characteristics were found. In conclusion, the results confirmed that the suggested system for evaluating the suitability of biodegradable lubricants is applicable in given laboratory or operating conditions. The conclusions can be used in practice for choosing the lubricant. The results can also help to create an order of appropriate oils. The conclusions can also be used by producers of lubricants as information about functional characteristics of their products