Autor: Tkach, L. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Characteristics and current situation of urban forests in Kharkiv region
Autorzy:: Musienko, S.
Lyalin, O.
Tkach, L.
Babenko, V.
Sulkowska, M.
Powiązania:: https://bibliotekanauki.pl/articles/38393.pdf
Data publikacji:: 2018
Wydawca:: Instytut Badawczy Leśnictwa
Źródło:: Folia Forestalia Polonica. Series A . Forestry; 2018, 60, 3
0071-6677
Pojawia się w:: Folia Forestalia Polonica. Series A . Forestry
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Estimation of temporary decommissioning impact on reliability and durability of oil pipelines
Autorzy:: Poberezhny, L.
Martyniuk, R.
Stanetsky, A.
Poberezhna, L.
Tkach, O.
Hrytsanchuk, A.
Powiązania:: https://bibliotekanauki.pl/articles/367993.pdf
Data publikacji:: 2019
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:: oil pipeline
conservation
temporary decommissioning
probability of non-destruction
pipeline steel 13G1S-U
rurociąg naftowy
konserwacja
wycofanie tymczasowe z eksploatacji
prawdopodobieństwo nieniszczenia
stal rurociągowa
Opis:: Purpose: Due to changes in the volume of oil transportation, part of the pipelines must be temporarily decommissioned. The purpose of the work is theoretical and experimental study of pressure fluctuations during operation of oil pipelines and their impact on the durability of the pipeline material in work state and after temporary decommissioning (conservation). Design/methodology/approach: The results of oil pressure fluctuation research have given a chance to choose the terms of experimental research providing of the pipe metal mechanical features changes research during oil pipeline exploitation. Findings: Fatigue test modes are selected based on the calculations of the mathematical model developed. Experimental studies of the dependence of the fatigue strength of the pipe material on the conditions of operation have been carried out, which made it possible to determine the parameters of the fatigue curve of the samples. Has been defined that fatigue strength for the new metal pipe samples is more for 20-25% than for the metal samples which had the contacts with lime milk and for 30-40% more than for metal samples which were under exploitation. Research limitations/implications: In the future, more combination of "pipe material - preservation medium" should be explored to establish pain of general regularities. Practical implications: The probabilistic curves of the pipeline non-destruction are constructed, which will be used for practical calculations of the reliability and durability of the 13G1S-U steel pipelines. Originality/value: Mathematical model is made that describes non-stationary oil moves in oil pipeline, that has been caused by jump like changes of oil supply in oil pipeline, on this basis was defined, that oil pressure in oil pipeline provides within non stationary process in a range of 0.4-0.6 Hz frequency and amplitude fluctuation of pressure is 0.1-0.5 MPa.
Źródło:: Journal of Achievements in Materials and Manufacturing Engineering; 2019, 94, 1-2; 22-31
1734-8412
Pojawia się w:: Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Nanostructural Superconducting Materials for Fault Current Limiters and Cryogenic Electrical Machines
Autorzy:: Prikhna, T.
Gawalek, W.
Savchuk, Ya.
Sergienko, N.
Moshchil, V.
Sokolovsky, V.
Vajda, J.
Tkach, V.
Karau, F.
Weber, H.
Eisterer, M.
Joulain, A.
Rabier, J.
Chaud, X.
Wendt, M.
Dellith, J.
Danilenko, N.
Habisreuther, T.
Dub, S.
Meerovich, V.
Litzkendorf, D.
Nagorny, P.
Kovalev, L.
Schmidt, Ch.
Melnikov, V.
Shapovalov, A.
Kozyrev, A.
Sverdun, V.
Kosa, J.
Vlasenko, A.
Powiązania:: https://bibliotekanauki.pl/articles/1549637.pdf
Data publikacji:: 2010-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Sv
74.81.Bd
74.70.Ad
74.78.Na
74.62.Fj
74.25.Ld
74.62.Dh
74.25.Ha
Opis:: Materials of the Y-Ba-Cu-O (melt-textured $YBa_{2}Cu_{3}O_{7-δ}$-based materials or MT-YBCO) and Mg-B-O ($MgB_{2}$-based materials) systems with high superconducting performance, which can be attained due to the formation of regularly distributed nanostructural defects and inhomogeneities in their structure can be effectively used in cryogenic technique, in particular in fault current limiters and electrical machines (electromotors, generators, pumps for liquid gases, etc.). The developed processes of high-temperature (900-800°C) oxygenation under elevated pressure (16 MPa) of MT-YBCO and high-pressure (2 GPa) synthesis of $MgB_{2}$-based materials allowed us to attain high superconductive (critical current densities, upper critical fields, fields of irreversibility, trapped magnetic fields) and mechanical (hardness, fracture toughness, Young modulus) characteristics. It has been shown that the effect of materials properties improvement in the case of MT-YBCO was attained due to the formation of high twin density (20-22 $μm^{-1}$), prevention of macrocracking and reduction (by a factor of 4.5) of microcrack density, and in the case of $MgB_{2}$-based materials due to the formation of oxygen-enriched as compared to the matrix phase fine-dispersed Mg-B-O inhomogeneities as well as inclusions of higher borides with near-$MgB_{12}$ stoichiometry in the Mg-B-O matrix (with 15-37 nm average grain sizes). The possibility is shown to obtain the rather high $T_{c}$ (37 K) and critical current densities in materials with $MgB_{12}$ matrix (with 95% of shielding fraction as calculated from the resistant curve).
Źródło:: Acta Physica Polonica A; 2010, 117, 1; 7-14
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: ZnO films: propeties determined by electronic microscopy and ellipsometry
Autorzy:: Rakov, M.
Poperenko, L.
Tkach, V.
Yurgelevich, I.
Powiązania:: https://bibliotekanauki.pl/articles/385183.pdf
Data publikacji:: 2009
Wydawca:: Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:: reactive magnetron sputtering
Beattie’s method
semi-infinite medium
AFM
SEM
nanostructures
Opis:: Zinc oxide is a good material for application in nanoand optoelectronics due to its notable features, for example, large band gap. In this work ZnO films deposited by reactive magnetron sputtering at various pressure of residual gases and different temperatures of the substrate are investigated. The spectral dependences of ellipsometric parameters and of the films are determined by ellipsometry. The effective values of optical constants and are calculated. The roughness and the texture of the surfaces are obtained by Atomic-Force Microscopy (AFM) and Scanning Electronic Microscopy (SEM). One indicates that the refractive index decreases when reducing the pressure of residual gases, and the roughness decreases when elevating the temperature of the substrate. Thus, the behavior of some properties of the films at various conditions of deposition is determined.
Źródło:: Journal of Automation Mobile Robotics and Intelligent Systems; 2009, 3, 4; 112-114
1897-8649
2080-2145
Pojawia się w:: Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Superconductivity in U-T Alloys (T = Mo, Pt, Nb, Zr) Stabilized in the Cubic γ-U Structure
Autorzy:: Sowa, S.
Kim-Ngan, N.
Krupska, M.
Paukov, M.
Tkach, I.
Havela, L.
Powiązania:: https://bibliotekanauki.pl/articles/1398594.pdf
Data publikacji:: 2016-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 81.05.Bx
74.70.Ad
72.15.Cz
Opis:: Using ultrafast cooling (with the cooling rate up to 10⁶ K/s) helps to minimize the T-alloying concentration (T = Mo, Pt, Pd, Nb, Zr) necessary to retain the γ-U phase down to low temperatures. All investigated splat-cooled U-T alloys become superconducting with $T_{c}$ in the range of 0.61-2.11 K. The bulk character of superconductivity can be concluded for some of the splats when comparing the specific-heat anomaly at $T_{c}$ with the BCS theory prediction.
Źródło:: Acta Physica Polonica A; 2016, 130, 2; 521-526
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Amorphous 5f Ferromagnetic Hydrides $UH_{3}Mo_{x}$
Autorzy:: Tkach, I.
Kim-Ngan, N.
Maškova, S.
Andreev, A.
Matěj, Z.
Havela, L.
Powiązania:: https://bibliotekanauki.pl/articles/1369135.pdf
Data publikacji:: 2014-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 75.50.Kj
75.50.Vv
72.15.Cz
Opis:: γ-U metal, stabilized down to room temperature in the bcc structure by Mo doping, can absorb hydrogen at high $H_{2}$ pressures only. The product is amorphous hydride $UH_{3}Mo_{x}$ analogous to $β-UH_{3}$. Such hydrides are ferromagnetic with high Curie temperatures (up to 200 K), enhanced with respect to $β-UH_{3}$. Magnetic moment of U also increases. Large disorder together with high anisotropy lead to a very high coercivity, reaching 4 T at low temperatures. As amorphization normally tends to suppress magnetic ordering of U compounds, such hydrides represent a new class of materials, amorphous U-based ferromagnets with relatively high Curie temperature.
Źródło:: Acta Physica Polonica A; 2014, 126, 1; 292-293
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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