Typy nepriameho merania

Riadiace systémy potrebujú informácie o relevantných procesných veličinách. Niekedy však tieto veličiny nevieme v reálnych technológiách priamo merať. V tomto prípade je vhodné použiť nepriame meranie. Autori sa v tomto príspevku pokúsili popísať základy teórie nepriameho merania, jeho klasifikácie a rôzne štruktúry a tieto následne ukázať na niektorých aplikáciách.The control systems need information about relevant variables. Sometime, these relevant variables we are not know to measure in real technologies. In this case is suitable to use the indirect measurement. Authors try to describe the bases of theory of indirect measurement, the classification methods and structures of indirect measurement and briefly to describe some application

Complex research and innovation program of the raw materials thermal treatment

Thermal treatment of raw materials takes place in many industries, especially in mining and processing industry. Thermal processes significantly contribute to the total cost of production and their technical and technological level significantly impacts the competitiveness of manufacturing companies in world markets. In the field of thermal treatment of carbonate raw materials, shaft furnaces, rotary kilns and deck furnaces are mainly used. By background optimizing of these aggregates, their rationalization opportunities have been practically exhausted. Further improvement is possible by moving the existing innovation borders or changing to different design solutions

Structure, mechanical and tribological properties of Mo-S-N solid lubricant coatings

Solid lubricant coatings deposited by plasma-assisted deposition techniques represent modern way to reduce the coefficient of friction in lubricant-free sliding contacts. Molybdenum disulphide (MoS2 ) is perhaps the most known and applied solid lubricant coating; however, its use is strictly limited by low hardness and environmental sensitivity. To improve mechanical and tribological properties, we doped MoS2 coating with nitrogen. Mo-S-N self-lubricant films were deposited by pulsed d. c. High Target Utilisation Sputtering (HiTUS) in reactive atmosphere. The effect of deposition conditions on chemical composition, structure and mechanical properties of MoSx and Mo-S-N coatings was studied; films with the most promising properties have been selected for tribological testing. MoSx film with the elemental composition sulphur to molybdenum (S/Mo ratio) 1.6 exhibited the coefficients of friction (COFs) in humid air 0.17 and 0.07 for loads 2 and 15 N, respectively. Mo-S-N films were prepared with nitrogen content in a range of 11 to 50 at., whereas S/Mo ratio varied from 1.35 to 0.4. Mo-S-N films were amorphous or nanostructured with nanograins of molybdenum disulphide. Hardness increased with N content up to 14 GPa for film with the highest content of nitrogen. Friction behaviour in humid air was evaluated using a ball-on-disk tribometer. Globally, the doping with N resulted in hardness in Mo–S–N films one order of magnitude higher and wear rate two orders of magnitude lower than in an undoped one, keeping the friction coefficient at the same level or even lower. These coatings showed remarkable friction coefficients in humid air from 0.28 to 0.05 with loads from 2 to 15 N, respectively. The excellent friction properties were attributed to the formation of a thin molybdenum disulphide tribofilm at the sliding interface. HiTUS represents a very promising way of producing thin films on the thermally sensitive substrates (e.g. bearing steel) with desired properties. </p

Thermally induced structural evolution and age-hardening of polycrystalline V1–xMoxN (x ≈ 0.4) thin films

Rocksalt-structure (B1) (V,Mo)N alloys are inherently hard and tough ceramics. However, the mechanical properties and thermal stability of (V,Mo)N solid solutions at temperatures ⪆ 700 °C of relevance for practical applications have not been previously investigated. In this work, we synthesize single-phase B1 polycrystalline V0.57Mo0.43N0.95 coatings to investigate the effects induced by temperature on the nanostructural evolution and hardness (H) of the material. Nanoindentation measurements show that the as-deposited film (H = 23 ± 3 GPa) becomes ≈30% harder (up to 31 ± 2 GPa) upon annealing at 730 °C. Experimental characterization and analyses, based on dispersive X-ray spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM), reveal that the age-hardening effect originates from decomposition of the solid solution into coherent strained cubic VN-rich/MoN-rich domains. The experimental results are complemented by the composition/temperature (V,Mo)N phase diagram – constructed upon ab initio molecular dynamics free-energies – which indicates that the separation observed in the solid solutions is of spinodal nature. Films annealed at temperatures exceeding 850 °C undergo structural coarsening, with formation of hexagonal MoxNy and cubic VN phases, which cause a decrease in hardness to ≈22 GPa. Our present findings indicate that (V,Mo)N coatings may offer outstanding mechanical performances during operation at elevated temperatures