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Wyszukujesz frazę "Král, P." wg kryterium: Autor


Wyświetlanie 1-15 z 15
Tytuł:
Reliability theory
Autorzy:
Janošková, K.
Král, P.
Powiązania:
https://bibliotekanauki.pl/articles/311933.pdf
Data publikacji:
2013
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
teoria niezawodności
inżynieria niezawodności
reliability theory
reliability engineering
Opis:
The contribution deals with the issue of reliability theory and its principles used in the field of reliability engineering. The contribution focuses attention on the mutual linkage among risk engineering, quality engineering and reliability engineering, defines the term of reliability and clarifies reliability theory in general. The article gives an overview of the most frequently used indicators widely used in reliability theory such as probability density of failure occurring, mean and (high) failure rate, mean time between failures, mean time to failure, average life etc. and briefly defines selected reliability systems used in reliability analyses.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2013, 14, 3; 1053-1058
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Excitation of Electron Wave Packets in Low-Dimensional Semiconductor Structures by Inhomogeneous Light Pulses
Autorzy:
Král, P.
Mašek, J.
Powiązania:
https://bibliotekanauki.pl/articles/1921602.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.90.+y
78.90.+t
Opis:
Generation of electron wave packets by space inhomogeneous light pulses is studied in low-dimensional semiconductor systems. Examination of their free propagation for ultrashort times as well as in the stationary excitation regime is performed. Non-classical effects related to the inhomogeneity of the source are predicted.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 697-701
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Profit margin in supply chain model
Autorzy:
Král, P.
Janošková, K.
Powiązania:
https://bibliotekanauki.pl/articles/311843.pdf
Data publikacji:
2013
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
łańcuch dostaw
zarządzanie łańcuchem dostaw
zysk
marża
supply chain
supply chain management
profit margin
Opis:
This contribution clarifies basic principles of profit margin in supply chain theory, defines the term supply chain, deals with the issue of double margin and determines quantitative characteristics of serial, parallel and mixed supply chain model of multiply margin.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2013, 14, 3; 1059-1064
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of σ-phase formation on long-term durability of welding joints in SUPER 304H steels
Autorzy:
Horváth, J.
Král, P.
Janovec, J.
Powiązania:
https://bibliotekanauki.pl/articles/1112347.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.70.Jb
68.37.Ma
81.30.Mh
81.20.Vj
62.20.mj
Opis:
Article presents results on the analysis of secondary phases formed in the medium-term static isothermal ageing welding joints of a SUPER 304H (675°C/2×10⁴ h). The investigations of the precipitates were focused on the occurrence of σ-phase because its formation leads to significant deterioration of mechanical properties. The microstructure was investigated on microscopic level by scanning/transmission electron microscopy. The distribution and quantification of brittle σ-phase were studied on macroscopic level by color etching method using light optical microscopy. The effect of microstructural changes (σ-phase formation) on the impact strength of an aged base material was investigated. For comparison impact tests on received state material were also performed. The results showed that long-term ageing led to the significant reduction of impact strength as a result of the formation of the σ-phase. It was found that the σ-phase distribution is influenced by welding process. The influence of brittle σ-phase on long-term durability of the degraded steel regarding its insufficient impact strength has been discussed.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 960-962
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure Mechanisms Governing the Creep Life of Ultrafine-Grained Cu-0.2 wt%Zr Alloy
Autorzy:
Kral, P.
Svoboda, M.
Dvorak, J.
Kvapilova, M.
Sklenicka, V.
Powiązania:
https://bibliotekanauki.pl/articles/1418438.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
61.66.Dk
62.20.Hg
68.37.Lp
Opis:
Equal-channel angular pressing was conducted at room temperature and extrusion was performed up to 12 passes using route where the billets were rotated by 90° in the same sense between consecutive passes. Tensile creep tests were performed at 473, 573 and 673 K at different constant applied stresses. It was observed that the original coarse grain size of unprocessed alloy was reduced to 0.3 μm after 8 equal-channel angular pressing passes and the grain growth during creep was restricted by precipitates with the mean diameter ≈ 4.0 nm. No significant effect on creep resistance was found after one equal-channel angular pressing pass at 473 and 573 K. However, the longest time to fracture was exhibited by alloy after 2 equal-channel angular pressing passes at 573 and 673 K but with further increasing number of equal-channel angular pressing passes a decrease in the time to fracture was observed. Nevertheless, the beneficial effect of equal-channel angular pressing on creep resistance was still documented after 8 passes for temperatures of 473 and 573 K. By contrast, creep tests performed at 673 K showed that the time to fracture of ultrafine-grained material is shorter as compared with that for as-received state. The 3D laser measurement of surface showed that the creep fracture process is accelerated by formation of vertical surface step relief and cavitation at the intersection of the shear bands during creep.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 457-460
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Long-term Annealing and Hot Bending on Creep of P92 Pipe
Autorzy:
Kral, P.
Dvorak, J.
Kvapilova, M.
Kucharova, K.
Sklenicka, V.
Svobodova, M.
Cmakal, J.
Powiązania:
https://bibliotekanauki.pl/articles/1402074.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
81.40.-z
62.20.Hg
68.37.Hk
Opis:
This work is focused on the creep behaviour of the thick-walled hot bended P92 pipe, with an outer diameter of 350 mm and wall thickness of 39 mm, in its different parts, namely in straight parts and bends. Selected creep specimens machined from axial section of pipe were thermally aged at 650°C to simulate microstructure degradation typical for long-term service conditions. Subsequent tensile creep tests at constant load were performed at 600°C under 140 MPa and creep behaviour of various structure states was compared. Microstructure was investigated by scanning electron microscopy equipped with electron backscatter diffraction. It was found that ageing at 650°C for 10⁴ h caused the significant reduction of creep resistance down to about 10% of initial state and an additional slight reduction of creep resistance after longer ageing for 2×10⁴ h. Further, creep behaviour was significantly influenced by specimen position in the extrados and intrados parts of bends. Microstructure investigation revealed that long-term annealing has negligible effect on high-angle grain boundary spacing and misorientation. By contrast, creep deformation of long-term annealed specimens led to significant decreasing in high-angle grain boundary spacing and caused a change in the misorientation distribution of boundaries.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 543-547
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Creep Behavior of a Zirconium Alloy Processed by Equal-Channel Angular Pressing
Autorzy:
Sklenicka, V.
Dvorak, J.
Kral, P.
Svoboda, M.
Kvapilova, M.
Kopylov, V.
Nikulin, S.
Dobatkin, S.
Powiązania:
https://bibliotekanauki.pl/articles/1418491.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.40.Lm
62.20.Hg
81.05.-t
81.07.Bc
81.70.Bt
Opis:
A Zr-2.5 wt%Nb alloy was processed by equal-channel angular pressing and then tested under creep conditions at 623 K using a tensile stress within the range from 120 to 300 MPa. The results show conventional power-law creep with a stress exponent of n > 3 which is consistent with an intragranular dislocation process involving the glide and climb of dislocations. It is demonstrated that diffusion creep is not important in these tests. For comparison purposes, the experiments were conducted using both the unprocessed alloy and after processing by equal-channel angular pressing. It was found that under same testing conditions the measured minimum creep rates in the pressed alloy with ultrafine grain sizes were faster than in the same alloy in a coarse-grained unprocessed condition.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 485-489
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of eccentricity of load on critical force of thin-walled columns CFRP
Autorzy:
Wysmulski, P.
Kráľ, J.
Powiązania:
https://bibliotekanauki.pl/articles/102239.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
finite element method
buckling
eccentricity load
thin-walled structures
laminate
composite CFRP
Opis:
The subject of study was a thin-walled C-section made of carbon fiber reinforced polymer (CFRP). Column was subjected to eccentric compression in the established direction. In the computer simulation, the boundary conditions were assumed in the form of articulated support of the sections of the column. Particular studies included an analysis of the effects of eccentricity on the critical force value. The research was conducted using two independent research methods: numerical and experimental. Numerical simulations were done using the finite element method using the advanced system Abaqus®. The high sensitivity of the critical force value corresponding to the local buckling of the channel section to the load eccentricity was demonstrated.
Źródło:
Advances in Science and Technology. Research Journal; 2017, 11, 3; 109-113
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CNC milling machine precision analysis through numerical modelling
Autorzy:
Svetlík, J.
Demeč, P.
Kráľ, J.
Powiązania:
https://bibliotekanauki.pl/articles/102601.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
accuracy of manufacturing machine
virtual prototyping
modal analysis
virtual model
Opis:
The motive behind the effort to make virtual prototyping more sophisticated is first of all cost reduction of manufacturing machine design, followed by reduction of lead time for development, prototyping and testing of the pre-manufacturing machine series. This article deals with the analysis of manufacturing precision of a 3-axial, numerically controlled milling machine. The methodology for precision analysis rests on a selected simplified numerical calculation model of a manufacturing machine on which virtual machining has been conducted. The mechanical inaccuracy itself is calculated by computer via the FEM analysis. The results are processed for visualization by the Excel software.
Źródło:
Advances in Science and Technology. Research Journal; 2017, 11, 2; 212-219
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Substantially Higher Corrosion Resistance in AE42 Magnesium Alloy through Corrosion Layer Stabilization by ECAP Treatment
Autorzy:
Minárik, P.
Král, R.
Hadzima, B.
Powiązania:
https://bibliotekanauki.pl/articles/1419053.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
82.45.Bb
Opis:
The corrosion properties of magnesium alloy AE42, just extruded and with posterior eight passes through equal channel angular pressing after extrusion, were investigated in 0.1 M NaCl by electrochemical impedance spectroscopy. The obtained samples were compared using scanning electron microscopy micrographs of the corrosion layers created on the surface of the specimens. The background of the substantial higher corrosion resistance of the samples after equal channel angular pressing treatment was found to be the much thicker and stable corrosion layer and smaller separating fragments in comparison with the just extruded samples. The lowering of the grain size by severe plastic deformation, especially by the equal channel angular pressing treatment was found to be also responsible for the enhancement of the corrosion resistance in AE42 class of magnesium alloys.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 614-617
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evolution of Corrosion Resistance in the LAE442 Magnesium Alloy Processed by ECAP
Autorzy:
Minárik, P.
Král, R.
Janeček, M.
Chmelík, F.
Hadzima, B.
Powiązania:
https://bibliotekanauki.pl/articles/1402153.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
82.45.Bb
Opis:
The influence of processing by equal channel angular pressing on the corrosion resistance was investigated in the extruded LAE442 magnesium alloy by the linear polarization method. Continuous increase of the corrosion resistance with the increasing number of passes was measured. The polarization resistance of the 12P sample was substantially higher as compared to the extruded state. The results were discussed in terms of the corrosion layers formed on the surface after seven days of immersion. It was concluded that the substantial increase of polarization resistance was caused by the combined effect of grain refinement and aluminum and lithium oxides formation within the corrosion layer.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 772-774
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Microstructure on the Corrosion Resistance of the AE42 Magnesium Alloy Processed by Rotary Swaging
Autorzy:
Minárik, P.
Zemková, M.
Král, R.
Mhaede, M.
Wagner, L.
Hadzima, B.
Powiązania:
https://bibliotekanauki.pl/articles/1402163.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
82.45.Bb
Opis:
Microstructure and corrosion resistance of the AE42 commercial alloy processed by extrusion and rotary swaging were investigated. Microstructure characterization showed an increasing volume fraction of the refined grains with increasing stage of swaging processing. However, their presence was limited solely to the peripheral ring of ≈1 mm in all studied conditions of swaged material. Corrosion resistance investigation showed continuous decrease of polarization resistance that was attributed to the grain refinement and insufficient homogenization of the alloying elements during the swaging process.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 805-807
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Grain Refinement after Various Thermo-Mechanical Treatments in AZ80 and ZK60 Magnesium Alloys
Autorzy:
Ryspaev, T.
Janecek, M.
Minárik, P.
Wesling, V.
Wagner, L.
Kral, R.
Powiązania:
https://bibliotekanauki.pl/articles/1419057.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.40.Gh
81.07.Bc
Opis:
The effect of thermal processing prior to severe plastic deformation by extrusion and swaging on grain refinement in ZK60 and AZ80 alloys was studied. The alloys received in direct-chill cast condition were homogenized at 415C and annealed (over-aged) at temperatures from 200 to 380°C. Both the direct-hill cast and over-aged conditions were extruded at T = 300C using an extrusion ratio of ER = 19. Hot extrusion resulted in substantial grain refinement in both cases, the effect being stronger in the over-aged material. The extruded bars were severe plastically deformed at 250C by swaging. Swaging refined further the grain size depending on the deformation ratio (number of passes). At optimal processing conditions the grain size was 450 nm and 570 nm for the AZ80 and ZK60 alloys, respectively.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 622-624
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interrelation of Microstructure and Corrosion Resistance in Biodegradable Magnesium Alloys with Aluminum, Lithium and Rare Earth Additions
Autorzy:
Minárik, P.
Landa, M.
Lesná, I.
Zemková, M.
Jablonská, E.
Hadzima, B.
Janeček, M.
Král, R.
Powiązania:
https://bibliotekanauki.pl/articles/1402061.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
82.45.Bb
87.85.J-
43.40.Le
Opis:
The influence of equal channel angular pressing and rotary swaging on the microstructure and corrosion resistance was investigated in three magnesium alloys with the addition of aluminum, lithium and rare earth elements - AE21, AE42 and LAE442. The processing resulted in grain refinement in all cases; nevertheless, the effect on the corrosion resistance was ambiguous. A continuous increase of the polarization resistance during the gradual equal channel angular pressing was observed in the AE42 and LAE442 alloys, whereas there was almost no effect in the AE21 alloy. The rotary swaging of AE42 resulted in a decrease of polarization resistance. The increase of polarization resistance in the alloys with the higher concentration of alloying elements was caused by the combined effect of grain refinement and better dispersion of particles in the matrix thanks to shear deformation during equal channel angular pressing. In the AE42 alloy, the increase of the corrosion resistance after equal channel angular pressing was also proven by chemical analysis of the solution and acoustic emission detection. This beneficial effect was not observed when the concentration of alloying elements was lower or when the deformation mode was different from shearing.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 491-496
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic-Emission Study of Intermittency of Plastic Flow during Twinning and Dislocation Glide
Autorzy:
Shashkov, I.
Lebedkina, T.
Lebyodkin, M.
Dobron, P.
Chmelik, F.
Kral, R.
Parfenenko, K.
Mathis, K.
Powiązania:
https://bibliotekanauki.pl/articles/1418404.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.F-
62.65.+k
05.65.+b
64.60.av
Opis:
Recent studies of plastic deformation with the aid of acoustic emission techniques proved an intermittent, scale-invariant character of plastic processes, as reflected in power-law statistical distributions. In some cases, the power-law exponents display close values leading to hypothesis of universality of scaling laws for various mechanisms of plasticity. Nevertheless, the accurate determination of the power law may be impeded by some sources of errors inevitable in real conditions, in particular, by superposition of individual acoustic emission events. In the present work, the sensitivity of the apparent statistics to the variation of the parameters of individualization of acoustic emission events is examined using Mg and Al based alloys. Both these alloys exhibit a highly cooperative character of plastic deformation, leading to strong acoustic activity which is governed by distinct microscopic mechanisms - mechanical twinning and the Portevin-Le Chatelier effect, respectively.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 430-434
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-15 z 15

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