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Wyszukujesz frazę "Michalek, T." wg kryterium: Autor


Wyświetlanie 1-15 z 15
Tytuł:
Simulations of the water freezing process: numerical benchmarks
Autorzy:
Michałek, T.
Kowalewski, T. A.
Powiązania:
https://bibliotekanauki.pl/articles/1955733.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
numerical simulation
numerical benchmarks
finite volume method
fixed grid enthalpyporosity method
volume of fluid
solidification
free surface flow
Opis:
Three numerical benchmarks concerning the freezing of water in small enclosures are analysed using the commercial FLUENT code. The first case is a steady-state natural convection in a differentially heated cavity for temperatures near the freezing point. In the second case, the freezing of water in a differentially heated cavity is simulated. The third case describes a simulation of freezing water in the presence of forced convection and a free surface flow. Two finite-differences numerical codes are used to verify results of the FLUENT simulations for the natural convection and solidification in the differentially heated cavity. It is found that the simulation of water solidification requires very fine meshes and short time steps, extending the computational time to the extreme.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 3; 389-408
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wheel/rail contact geometry research and development of locomotive Class 744.0 as examples of R&D activities of the Jan Perner Transport Faculty
Badania geometrii kontaktu koło/szyna i badania lokomotywy serii 744.0 jako przykłady działalności R&D Wydziału Transportu Jana Perner
Autorzy:
Zelenka, J.
Michalek, T.
Kohout, M.
Powiązania:
https://bibliotekanauki.pl/articles/251725.pdf
Data publikacji:
2016
Wydawca:
Instytut Naukowo-Wydawniczy TTS
Tematy:
locomotive 744.0
Department of Transport
University of Pardubice
lokomotywa 744.0
Wydziału Transportu
Uniwersytet w Pardubicach
Opis:
The Jan Perner Transport Faculty (JPTF) of the University of Pardubice and especially its Department of Transport Means and Diagnostics deals with research and development activities in the branch of railway vehicles. There are two basic reasons for that. At first, it is incumbent upon all academic workers to pursue the science and research according to the Czech law concerning the universities. And the second reason is a relation to the educational process - if the JPTF wants to offer a high quality education in the specialization "Railway Vehicles" (which is offered in Czech as well as English language today) to its students, the research activities of the academic workers (i.e. the teachers) allow them to stick to the newest trends in the branch. In this article, particular examples of cooperation of the JPTF with producers as well as operators of railway rolling stock are presented as a contribution of the faculty to the research and development in the branch of railway vehicles.
W artykule przedstawiono aktywność badawczą Wydziału Transportu Uniwersytetu w Pardubicach (Czechy) w zakresie pojazdów kolejowych. Scharakteryzowano wyposażenie laboratoriów wykorzystywane do badań teoretycznych i eksperymentalnych. Skoncentrowano się na zagadnieniach dostosowania profili kól do specyficznych warunków ruchowych oraz współpracy przy konstrukcji nowej lokomotywy.
Źródło:
TTS Technika Transportu Szynowego; 2016, 1-2; 80-83
1232-3829
2543-5728
Pojawia się w:
TTS Technika Transportu Szynowego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The use of Lempel-Ziv complexity to analyze turbulence and flow randomness based on velocity fluctuations
Autorzy:
Blonski, S.
Pregowska, A.
Michalek, T.
Szczepanski, J.
Powiązania:
https://bibliotekanauki.pl/articles/201218.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
turbulence
complexity
entropy
randomness
Opis:
One of the mathematical tools to measure the generation rate of new patterns along a sequence of symbols is the Lempel-Ziv complexity (LZ). Under additional assumptions, LZ is an estimator of entropy in the Shannon sense. Since entropy is considered as a measure of randomness, this means that LZ can be treated also as a randomness indicator. In this paper, we used LZ concept to the analysis of different flow regimes in cold flow combustor models. Experimental data for two combustor’s configurations motivated by efficient mixing need were considered. Extensive computer analysis was applied to develop a complexity approach to the analysis of velocity fluctuations recorded with hot-wire anemometry and PIV technique. A natural encoding method to address these velocity fluctuations was proposed. It turned out, that with this encoding the complexity values of the sequences are well correlated with the values obtained by means of RMS method (larger/smaller complexity larger/smaller RMS). However, our calculations pointed out the interesting result that most complex, this means most random, behavior does not overlap with the “most turbulent” point determined by the RMS method, but it is located in the point with maximal average velocity. It seems that complexity method can be particularly useful to analyze turbulent and unsteady flow regimes. Moreover, the complexity can also be used to establish other flow characteristics like its ergodicity or mixing.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 5; 957-962
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Planning the Waypoint - Following Task for a Unicycle - Like Robot in Cluttered Environments
Autorzy:
Gawron, T.
Michalek, M. M.
Powiązania:
https://bibliotekanauki.pl/articles/384869.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
VFO control
waypoint-following
unicyclelike robot
combinatorial search
controller-driven motion planning
Opis:
The paper presents a two-stage, global planning algorithm for the waypoint-following task realized by a unicycle-like robot in a clutiered environment. It assumes motion execution with the VFO (Vector Field Orientation) controller. The planner is a result of a controllerdriven design process and exploits particular properties of the VFO controller. Emphasis has been put on the plan safety in the sense of maximizing the distance from the obstacles. In the first stage of planning, an A*-like pathfinding algorithm is used to find a safe geometric plan (i.e. a polyline) in a two-dimensional occupancy grid. During the second stage, a sequence of waypoint posi tions is selected from the geometric plan and reference orientations at the waypoints are planned. Orienta tion planning exploits properties of the VFO controller used for subsequent motion execution. Proposed twostage algorithm admits changes of robot motion strategy (forward/backward movement) and has lower computational cost than the full configuration space search. Performance of the algorithm can be intuitively tuned with provided design parameters.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2015, 9, 1; 77-90
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistics of Tunneling Events in Three-Terminal Hybrid Devices with Quantum Dot
Autorzy:
Michałek, G.
Bułka, B.
Domański, T.
Wysokiński, K.
Powiązania:
https://bibliotekanauki.pl/articles/1030466.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.45.+c
73.23.Hk
72.70.+m
73.63.Kv
Opis:
We investigate statistics of the tunneling events in the short time limit in terms of the waiting time distribution (WTD), defined as the probability for a delay time between two subsequent transitions of particles, and consider it for a quantum dot (QD) strongly coupled to a superconducting and weakly coupled to two normal electrodes. Our study focuses on the WTD in the subgap transport, when coherent exchange of the Cooper pairs occurs between the QD and the superconductor. The dynamics can be described in terms of a Markovian generalized master equation for the reduced density matrix. We observe coherent oscillations between the Andreev bound states in the correlated jumps, both for the local and non-local WTDs. In addition the analysis of the transient currents give us some insight into dominant relaxation processes in short time scales.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 391-393
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Modelling of the Steel Flow in RH Apparatus
Modelowanie fizyczne przepływu stali w urządzeniu RH
Autorzy:
Pieprzyca, J.
Merder, T.
Saternus, M.
Michalek, K.
Powiązania:
https://bibliotekanauki.pl/articles/356316.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steel
vacuum degassing
RH apparatus
physical modelling
stal
odgazowanie próżniowe
urządzenie RH
modelowanie fizyczne
Opis:
he efficiency of vacuum steel degassing using RH methods depends on many factors. One of the most important are hydrodynamic processes occurring in the ladle and vacuum chamber. It is always hard and expensive to determine the flow character and the way of steel mixing in industrial unit; thus in this case, methods of physical modelling are applied. The article presents the results of research carried out on the water physical model of RH apparatus concerning the influence of the flux value of inert gas introduced through the suck legs on hydrodynamic conditions of the process. Results of the research have visualization character and are presented graphically as a RTD curves. The main aim of such research is to optimize the industrial vacuum steel degassing process by means of RH method.
Skuteczność procesu próżniowego odgazowania stali metodą RH zależy od wielu czynników. Jednym z ważniejszych są procesy hydrodynamiczne zachodzące w kadzi stalowniczej i komorze próżniowej. Określenie sposobu przepływu i mieszania się stali w urządzeniu przemysłowym jest bardzo trudne i kosztowne. W związku z tym do tego celu wykorzystuje się m. in. metody modelowania fizycznego. W artykule przedstawiono rezultaty badań przeprowadzonych na wodnym modelu fizycznym urządzenia RH, dotyczące wpływu wartości strumienia gazu obojętnego wprowadzanego przez dysze króćca ssącego na warunki hydrodynamiczne procesu. Wyniki badań mają charakter wizualizacji oraz przedstawione zostały w postaci krzywych retencji RTD. Cel tego typu badań związany jest z optymalizacją przemysłowego procesu próżniowego odgazowania stali metodą RH.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 3A; 1859-1863
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Andreev Spectroscopy in Three-Terminal Hybrid Nanostructure
Autorzy:
Michałek, G.
Bułka, B.
Urbaniak, M.
Domański, T.
Wysokiński, K.
Powiązania:
https://bibliotekanauki.pl/articles/1385343.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.23.Hk
74.45.+c
Opis:
We consider a hybrid three-terminal structure consisting of a quantum dot coupled to three leads, two normal and one superconducting. The current flowing between one of the normal and the superconducting electrodes induces voltage in the other normal (floating) electrode. The value of the induced voltage depends on the position of the Andreev levels in the quantum dot and is a measure of the interplay between the electron transfer and the subgap anomalous reflection processes. When the crossed (i.e. non-local) Andreev reflections dominate the induced potential in the normal electrode becomes negative. This situation occurs for the relatively strong coupling to the superconducting electrode and only outside the Coulomb blockade region. Taking the superconducting electrode as the voltage probe one gets additional information on competition of injected carriers.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 293-295
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of submerged entry nozzle on intermixed zone in round blooms with a diameter of 525 mm
Wpływ wylewu zanurzeniowego na strefę przejściową w okrągłych wlewkach ciągłych o średnicy 525 mm
Autorzy:
Michalek, K.
Gryc, K.
Tkadlečková, M.
Morávka, J.
Huczala, T.
Bocek, D.
Horáková, D.
Powiązania:
https://bibliotekanauki.pl/articles/350846.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ciągłe odlewanie
wylewy zanurzane typu SEN
SEN
strefa przejściowa
profil stężenia
continuous casting machine
steel round bloom
submerged entry nozzle
intermixed zone
concentration profile
Opis:
This work compares the experimental results of nickel concentration measurements in the intermixed zone of the continuously cast round blooms with a diameter of 525 mm using two types of submerged entry nozzles (SEN) - a straight-through nozzle and one with 5-ports. Based on determination of the system and optical interface in the blooms a detailed study of concentration profiles on the bloom surface in a small radius area, on the right side and then also on a cross-section of the blooms, was carried out. The results were further analysed using approximation models, and were to be used to verify the proposed model for predicting intermixed zones for a continuous casting machine, developed based on the results of physical and numerical modelling.
Praca przedstawia porównanie wyników pomiarów doświadczalnych stężenia niklu we wlewkach okrągłych o średnicy 525 mm odlewanych metodą COS z strefa przejściową, przy użyciu dwóch typów wylewów zanurzanych typu SEN - wylewu osiowego oraz promieniowego 5-strumieniowego. Pomiary wykonano na powierzchni wlewków oraz na ich przekroju poprzecznym przy użyciu metod optycznych. Analizę uzyskanych wyników pomiarów przeprowadzono wykorzystując modele aproksymujace. Uzyskane w ten sposób rezultaty wykorzystano do modernizacji opracowanego wcześniej w oparciu o rezultaty badan o charakterze modelowania fizycznego i numerycznego modelu do prognozowania wielkości strefy przejściowej dla badanego urządzenia do ciągłego odlewania stali.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 1; 187-191
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Modelling of Degassing Process by Blowing of Inert Gas
Autorzy:
Michalek, K.
Tkadlečková, M.
Socha, L.
Gryc, K.
Saternus, M.
Pieprzyca, J.
Merder, T.
Powiązania:
https://bibliotekanauki.pl/articles/351001.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
physical modelling
refining ladle
inert gas blowing
degassing process
impeller
Opis:
This paper deals with the possibilities of using physical modelling to study the degassing of metal melt during its treatment in the refining ladle. The method of inert gas blowing, so-called refining gas, presents the most common operational technology for the elimination of impurities from molten metal, e.g. for decreasing or removing the hydrogen content from liquid aluminium. This refining process presents the system of gas-liquid and its efficiency depends on the creation of fine bubbles with a high interphase surface, uniform distribution, long period of its effect in the melt, and mostly on the uniform arrangement of bubbles into the whole volume of the refining ladle. Physical modelling represents the basic method of modelling and it makes it possible to obtain information about the course of refining processes. On the basis of obtained results, it is possible to predict the behaviour of the real system during different changes in the process. The experimental part focuses on the evaluation of methodical laboratory experiments aimed at the proposal and testing of the developed methods of degassing during physical modelling. The results obtained on the basis of laboratory experiments realized on the specific physical model were discussed.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 987-992
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Approaches of Numerical Modelling of Solidification of Continuously Cast Steel Billets
Autorzy:
Tkadlečková, M.
Michalek, K.
Strouhalová, M.
Sviželová, J.
Saternus, M.
Pieprzyca, J.
Merder, T.
Powiązania:
https://bibliotekanauki.pl/articles/354682.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steel
steelmaking
continuous casting
numerical modelling
temperature field
porosity
Opis:
The paper evaluates two approaches of numerical modelling of solidification of continuously cast steel billets by finite element method, namely by the numerical modelling under the Steady-State Thermal Conditions, and by the numerical modelling with the Traveling Boundary Conditions. In the paper, the 3D drawing of the geometry, the preparation of computational mesh, the definition of boundary conditions and also the definition of thermo-physical properties of materials in relation to the expected results are discussed. The effect of thermo-physical properties on the computation of central porosity in billet is also mentioned. In conclusion, the advantages and disadvantages of two described approaches are listed and the direction of the next research in the prediction of temperature field in continuously cast billets is also outlined.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 1003-1008
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Modelling of Metal Melt Refining Process in Ladle with Rotating Impeller and Breakwaters
Autorzy:
Sviželová, J.
Tkadlečková, M.
Michalek, K.
Walek, J.
Saternus, M.
Pieprzyca, J.
Merder, T.
Powiązania:
https://bibliotekanauki.pl/articles/353863.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminium
refining
numerical modelling
rotating impeller
degassing
Opis:
The paper describes research and development of aluminium melt refining technology in a ladle with rotating impeller and breakwaters using numerical modelling of a finite volume/element method. The theoretical aspects of refining technology are outlined. The design of the numerical model is described and discussed. The differences between real process conditions and numerical model limitations are mentioned. Based on the hypothesis and the results of numerical modelling, the most appropriate setting of the numerical model is recommended. Also, the possibilities of monitoring of degassing are explained. The results of numerical modelling allow to improve the refining technology of metal melts and to control the final quality under different boundary conditions, such as rotating speed, shape and position of rotating impeller, breakwaters and intensity of inert gas blowing through the impeller.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 659-664
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research and Development of the Solidification of Slab Ingots from Special Tool Steels
Autorzy:
Tkadlečková, M.
Michalek, K.
Gryc, K.
Socha, L.
Jonšta, P.
Saternus, M.
Pieprzyca, J.
Merder, T.
Powiązania:
https://bibliotekanauki.pl/articles/356096.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tool steel
steelmaking
slab ingot
numerical modelling
porosity
Opis:
The paper describes the research and development of casting and solidification of slab ingots from special tool steels by means of numerical modelling using the finite element method. The pre-processing, processing and post-processing phases of numerical modelling are outlined. Also, problems with determining the thermophysical properties of materials and heat transfer between the individual parts of the casting system are discussed. Based on the type of grade of tool steel, the risk of final porosity is predicted. The results allowed to improve the production technology of slab ingots, and also to verify the ratio, the chamfer and the external/ internal shape of the wall of the new designed slab ingots.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1453-1458
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Tundish Slag Entrainment Using Physical Modelling
Autorzy:
Michalek, K.
Gryc, K.
Socha, L.
Saternus, M.
Tkadlečková, M.
Pieprzyca, J.
Merder, T.
Pindor, L.
Powiązania:
https://bibliotekanauki.pl/articles/353001.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steelmaking
tundish
slag entrainment
vortex
physical modelling
Opis:
This paper deals with the possibilities of using physical modelling to study the slag entrainment in the tundish. A level of steel in the tundish is changing during sequential continuous casting. The most significant decrease in the steel level occurs when replacing ladles. It is generally known that if the height of steel level in the tundish drops below a certain critical level, it may generate vortexes over the nozzles and as a consequence entrainment of tundish slag into individual casting strands can occur. Thus, it is necessary to identify the critical level of steel for specific operational conditions. In this paper, the development of physical modelling methodology is described as well as physical model corresponding to operational continuous casting machine No. 2 in Třinecké železárny, a.s. The obtained results are discussed.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 1; 257-260
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Modelling of Tundish Slag Entrainment under Various Technological Conditions
Autorzy:
Michalek, K.
Gryc, K.
Socha, L.
Tkadlečková, M.
Saternus, M.
Pieprzyca, J.
Merder, T.
Pindor, L.
Powiązania:
https://bibliotekanauki.pl/articles/351348.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steelmaking
tundish
slag entrainment
flow pattern
physical modelling
Opis:
This paper deals with the issue of physical modelling of vortexes creation and tundish slag entrainment over the mouth of the nozzle into the individual casting strands. Proper physical model is equivalent to the operational continuous casting machine No. 2 in TŘINECKÉ ŽELEZÁRNY, a.s. Physical modelling methodology and simulated operational conditions are shortly described. Physical modelling was used for the evaluation of current conditions of steel casting at the application of different impact pads in the tundish. Further, laboratory measurement on the physical model aiming the determination of exact critical periods of vortexes creation and study of the slag entrainment as a consequence of changes in surface level during the tundish refilling to standard level were realised. The obtained results were analysed and discussed.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1467-1471
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Solidification of Continuously Cast Steel Round Billets Using Numerical Modellin
Autorzy:
Tkadleckova, M.
Válek, L.
Socha, L.
Saternus, M.
Pieprzyca, J.
Merder, T.
Michalek, K.
Kováč, M.
Powiązania:
https://bibliotekanauki.pl/articles/353911.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steel
billet
continuous casting
numerical modelling
metallurgical length
Opis:
The paper is dedicated to the verification of solidification of continuously cast round steel billets using numerical modelling based on the finite element method. The aim of numerical modelling is to optimize the production of continuously cast steel billets of round format. The paper describes the pre-processing, processing and post-processing phases of numerical modelling. Also, the problems with determination of the thermodynamic properties of materials and the heat transfer between the individual parts of the casting system, including the definition of the heat losses along the casting strand in the primary and secondary cooling, were discussed. The first results of numerical simulation show the so-called thermal steady state of continuous casting. The temperature field, the metallurgical length and the thickness of the shell at the end of the mould were predicted. The further research will be concentrated on the prediction the risk of the cracks and the porosity based on the different boundary conditions.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 1; 221-226
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-15 z 15

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