Temat: method of characteristics - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Method of characteristics for design of centrifugal pump geometry
Autorzy:: Puzyrewski, R.
Zochowski, K.
Flaszyński, P.
Powiązania:: https://bibliotekanauki.pl/articles/1943212.pdf
Data publikacji:: 2010
Wydawca:: Politechnika Gdańska
Tematy:: pumps
inverse problem
method of characteristics
Opis:: The method of characteristics leads to the blade geometry of a centrifugal pump. The method is built taking the advantage of the governing equations of fluid mechanics written in a non-orthogonal coordinates system. The coordinate system is based on an analytically described boundary of a centrifugal pump. Some of the information concerning the designed geometry should be introduced in advance. The mass conservation equation needs the information of the blockage factor resulting from the blading thickness. In the momentum conservation equation the body force replaces the blading force together with the friction force. In the energy conservation equation the dissipation effects are represented by a loss coefficient. It is shown that while simplifying the body force vector, the set of equations reduces to a hyperbolic system which allows applying the method of characteristics. The shapes of surfaces representing the designed blading can be built from the trajectories of fluid particles.
Źródło:: TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2010, 14, 3; 249-256
1428-6394
Pojawia się w:: TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Simulation and discretization of random field in the slip-line method
Autorzy:: Przewłócki, J.
Powiązania:: https://bibliotekanauki.pl/articles/240960.pdf
Data publikacji:: 2003
Wydawca:: Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:: bearing capacity
method of characteristics
random field
Opis:: The paper deals with the problem of bearing capacity of a strip footing based on the random subsoil. The solution has been obtained in a framework of the slip-line method. In order to include randomness of the soil medium, a modification of the method of characteristics is proposed. In such an approach, the stochastic finite difference method based on the Monte Carlo technique has been adopted. It enables including a spatial variability of soil properties into the analysis and to determine its influence on the variance of the ultimate collapse load. It is assumed that the soil medium is purely cohesive and only its cohesion can be considered as a random field. The simulation algorithm of multi-dimensional random field, based on the diagonalisation of the covariance matrix by a transformation using a lower-triangle matrix is described. The problems of the medium discretization and stabilization of the solution are discussed.
Źródło:: Archives of Hydro-Engineering and Environmental Mechanics; 2003, 50, 4; 343-358
1231-3726
Pojawia się w:: Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Sufficient conditions for optimality for a mathematical model of drug treatment with pharmacodynamics
Autorzy:: Leszczynski, M.
Ratajczyk, E.
Ledzewicz, U.
Schättler, H.
Powiązania:: https://bibliotekanauki.pl/articles/255130.pdf
Data publikacji:: 2017
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:: optimal control
sufficient conditions for optimality
method of characteristics
pharmacodynamic model
Opis:: We consider an optimal control problem for a general mathematical model of drug treatment with a single agent. The control represents the concentration of the agent and its effect (pharmacodynamics) is modelled by a Hill function (i.e., Michaelis-Menten type kinetics). The aim is to minimize a cost functional consisting of a weighted average related to the state of the system (both at the end and during a fixed therapy horizon) and to the total amount of drugs given. The latter is an indirect measure for the side effects of treatment. It is shown that optimal controls are continuous functions of time that change between full or no dose segments with connecting pieces that take values in the interior of the control set. Sufficient conditions for the strong local optimality of an extremal controlled trajectory in terms of the existence of a solution to a piecewise defined Riccati differential equation are given.
Źródło:: Opuscula Mathematica; 2017, 37, 3; 403-419
1232-9274
2300-6919
Pojawia się w:: Opuscula Mathematica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: A numerical approach to the standard model of water hammer with fluid-structure interaction
Autorzy:: Henclik, S.
Powiązania:: https://bibliotekanauki.pl/articles/281051.pdf
Data publikacji:: 2015
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: water hammer
transient pipe flow
fluid-structure interaction
standard model
method of characteristics
Opis:: In the classic water hammer (WH) theory, 1D liquid flow in a quasi-rigid pipe is assumed. When the pipe is flexible or is fixed to the foundation with elastic supports, the dynamic fluid structure interaction (FSI) should be taken into account for more accurate modelling of the system behaviour. The standard model of WH-FSI for a straight pipe reach is governed by fourteen hyperbolic partial differential equations of the first order, two for 1D liquid flow and twelve for 3D motion of the pipe. This model is presented in the paper and an algorithm for its numerical solution based of the method of characteristics is proposed. Basic boundary conditions (BC) are shortly discussed. The important condition at the junction of two subpipes fixed to the foundation with a viscoelastic support is presented in details and a general method of its solution is proposed.
Źródło:: Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 543-555
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Mathematical model and numerical computations of transient pipe flows with fluid-structure interaction
Autorzy:: Henclik, S.
Powiązania:: https://bibliotekanauki.pl/articles/175378.pdf
Data publikacji:: 2010
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: waterhammer
transient pipe flow
fluid-structure interaction (FSI)
numerical modeling
method of characteristics
Opis:: Transient flows in closed conduits are of interest from over a century, but the dynamic interaction between the fluid and the pipe is taken into consideration more thoroughly just from a few decades. A standard model of the phenomenon consists of fourteen first order partial differential equations (PDE), two for a one-dimensional (1D) liquid flow and twelve for 3D pipe motion. In many practical cases however, a simpler four equations (4E) model can be used, where 1D longitudinal pipe movement is assumed. A short description of waterhammer event with fluidstructure interaction taken into account is presented in the article. The 4E mathematical model is presented in detail with the assumptions and main algorithms of computer program that has been developed. Two phase flow is assumed not to take place, but the friction between the liquid and the pipe wall are taken into consideration. A method of characteristics (MOC) with time marching procedure is employed for finding the solutions, but instead of direct solving the resulting finite difference equations (FDE) the “wave method” is proposed. Some other important elements of the algorithm are presented and selected results of numerical computations as well.
Źródło:: Transactions of the Institute of Fluid-Flow Machinery; 2010, 122; 77-94
0079-3205
Pojawia się w:: Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: A boundary condotions at modeling 1-D pulsating flows in pipes according to the method of characteristics
Autorzy:: Pałczyński, T.
Powiązania:: https://bibliotekanauki.pl/articles/246623.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: 1D simulations
Valve boundary conditions
method of characteristics
pulsating flow at pipes
Opis:: At this paper, there were compared three conceptions of boundary conditions and their definition at partially opened pipes. This is typical at inlet and exhaust pipes of internal combustion engines and piston compressors. At an introduction there were listed the current state of affairs at a one dimensional modelling pulsations according to the Method of Characteristics (MOC). Subsequently, there was presented the main idea of MOC. At the third chapter there were presented general guidelines at initial and boundary conditions definition. Next there are three descriptions of the analyzed problem. Firstly, there was presented partially open end phenomena at space and stage plane. Secondly, there was shown the theory of acoustic wave propagation with description of stage waves at analyzed ends of pipe. Lastly, there is a new conception of constant pressure valve boundary conditions, which is the synthesis of the both mentioned earlier. At the fourth paragraph there was shortly presented existing test rig dedicated to research of pulsating flow in pipes. This test rig was built at Flow Metrology Division of Lodz University of Technology [9]. At the second part of this chapter there were shown main assumption of elaborated simulation algorithm at Matlab Simulink environment. Lastly there were discussed simulation results compared with presented conceptions of boundary conditions.
Źródło:: Journal of KONES; 2012, 19, 2; 395-402
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Hydraulic transients analysis in pipe networks by the method of characteristics (MOC)
Autorzy:: Wichowski, R.
Powiązania:: https://bibliotekanauki.pl/articles/240954.pdf
Data publikacji:: 2006
Wydawca:: Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:: hydraulic transients
method of characteristics
single pipe
experimental measurement
pipe networks
numerical simulations
Opis:: The paper presents results of an experimental and theoretical study of the hydraulic transients in straight pipes and numerical simulations of unsteady flow in pipe networks. A mathematical model consists of a set of partial differential equations of hyperbolic type, which have been transformed by the method of characteristics into ordinary differential equations which are solved by the predictor-corrector method. Experimental tests have been performed, in order to examine the hydraulic transients phenomenon, in a single straight steel pipe. The experiments were carried out in the hydraulic laboratory of the Institute of Water Supply and Water Engineering, Environmental Engineering Faculty, Warsaw University of Technology. The numerical results show that the presented one dimensional model for a single pipe correctly describes the phenomenon since there is a good agreement with experimental maximum and minimum oscillations. In the paper, selected exemplary equations in a difference form for the pipe networks are also presented. One calculation example is given relating to the complex water-pipe network consisting of 17 loops, 48 pipelines and 33 nodes, supplied by two independent sources. Water-hammer throughout the whole pipeline network was caused by closing the gate valve at mid-point of one selected pipe. The results of the numerical calculations are presented in graphic form with respect to the final cross-sections of pipes.
Źródło:: Archives of Hydro-Engineering and Environmental Mechanics; 2006, 53, 3; 267-291
1231-3726
Pojawia się w:: Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Parameters affecting water hammer in plastic pipelines
Autorzy:: Urbanowicz, K.
Firkowski, M.
Powiązania:: https://bibliotekanauki.pl/articles/135271.pdf
Data publikacji:: 2018
Wydawca:: Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:: water hammer
unsteady flow
viscoelastic pipes
method of characteristics
partial differential equations
creep function
Opis:: Pressure pipes made of selected plastics are widely used in current water supply systems. Unfortunately, the theoretical basis for modeling transient flows in these pipes has not been clarified yet. For simplified one-dimensional numerical modeling, a model is commonly used in which the total deformation of the pipe walls is expressed by the sum of instantaneous and retarded deformations. One of the main problems lies in the correct experimental determination of the creep function defining the properties of the polymer. The influence of other parameters on which the numerical solution of the method of characteristics is based is the subject of the research presented in this paper.
Źródło:: Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2018, 54 (126); 35-43
1733-8670
2392-0378
Pojawia się w:: Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Symualcje jednowymiarowych przepływów pulsacyjnych w przewodach w oparciu o metodę charakterystyk
Simulations of 1-D pulsating flow at pipes according to the method of characteristics
Autorzy:: Pałczyński, T.
Powiązania:: https://bibliotekanauki.pl/articles/395294.pdf
Data publikacji:: 2012
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:: jednowymiarowe modelowanie zjawisk pulsacyjnych w przewodach
symulacje
MATLAB/Simulink
metoda charakterystyk
one-dimensional pulsating phenomena in pipes modeling
simulations
MATLAB Simulink
method of characteristics
Opis:: W pracy omówiono podstawowe informacje związane z koncepcją wykorzystania metody charakterystyk w modelowaniu przepływów w przewodach zasilanych pulsacyjnie. W dalszej części pracy zaprezentowano technologię opracowania modelu symulacyjnego. W końcowej części pracy przedstawiono przykładowe wyniki badań numerycznych, odniesione do badań eksperymentalnych, uzyskując potwierdzenie słuszności przyjętej koncepcji. Opisano główne zalety zaproponowanej koncepcji badań symulacyjnych a także kierunki dalszych badań
At this paper there were presented basic information connected with concept of usage of Method of Characteristics at pipes with pulsating flow supplied modeling. At the next section of paper there were shown technology of simulation model building. Simulation results compared with experiment complained the wisdom of proposed conception. There were also presented the main advantages of described model and the next steps of research.
Źródło:: Postępy Nauki i Techniki; 2012, 14; 197-207
2080-4075
Pojawia się w:: Postępy Nauki i Techniki
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Investigation on the structural, optical and topographical behavior of Cadmium oxide polycrystalline thin films using electrochemical depositing method at different times
Autorzy:: Abd, Ahmed N.
Dawood, Mohammed O.
Hassoni, Majid H.
Hussein, Ali A.
Powiązania:: https://bibliotekanauki.pl/articles/1192094.pdf
Data publikacji:: 2016
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:: Cadmium oxide
thin film
optical characteristics of film
electrochemical depositing method
Opis:: The optical and structure properties of Cadmium oxide (CdO) thin film prepared by electrochemical deposition method at different times (15, 30 and 60) min were investigated in this paper. Results of optical Transmission, absorption, reflection spectra, optical conductance, refractive index, extension coefficient, real and imaginary dielectric constants studies are reported. The optical transmittance of the CdO thin film which formed at room temperature was 20% at wavelength ≈350 nm then increases to 60% at wavelength ≈1100 nm for thin film of CdO. The band-gap was also calculated from the equation relating absorption coefficient with the wavelength. The energy band gap changes from 2.3eV (Bulk CdO) to 2.45eV (CdO thin film). The plotted graphs show the optical characteristics of the film which varied with the wavelength and the photon energy. The optical conductance and band-gap indicated that the film is transmitting within the visible range. The dielectric constant and optical conductance of the film initially decreases slowly with increase in photon energy. The extinction coefficient and refractive index of the films also evaluated, which affected with the change in transmittance. The structure of synthesised CdO thin film was analyzed by X-ray diffraction XRD which revealed that the CdO thin film are polycrystalline and have several peaks of cubic face structure. The crystallite size, dislocation density, microstrain and number of dislocations of the thin film were calculated and listed.
Źródło:: World Scientific News; 2016, 37; 249-264
2392-2192
Pojawia się w:: World Scientific News
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: Opracowanie metody szybkiej estymacji właściwości aerosprężystych samolotu w czasie prób flatterowych w locie - studium realizacji projektu
Elaboration of the method for quick estimation of aeroelastic characteristics during in-flight flutter tests - case study
Autorzy:: Niepokólczycki, A.
Powiązania:: https://bibliotekanauki.pl/articles/212957.pdf
Data publikacji:: 2011
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:: badania flatterowe samolotów
metoda szybkiej estymacji właściwości aerosprężystych samolotu
próby flatterowe w locie
flutter tests of aircraft structures
method for quick estimation of earoelastic characteristics
flutter tests in-flight
Opis:: Tytuł niniejszej pracy jest jednocześnie tytułem projektu rozwojowego zreałizowanego w ramach Programu Operacyjnego Innowacyjna Gospodarka. W pracy przedstawiono genezę projektu, cele, zespół wykonawców, opis projektu i jego realizacji Przedstawiono rezultaty projektu i analizę możliwości zapewnienia ich trwałości W podsumowaniu przedstawiono działania, które zostały już podjęte lub zostaną podjęte w przyszłości w celu wdrożenia rezultatów projektu do praktyki przemysłowej.
The title of this paper is also the title of the project that has been performed under the Operational Programme Innovative Economy 2007-2013. The paper presents the origin of the project, its aims, team, description of the project and its realisation. The summary presents the activities that have been already completed and those which will be undertaken in the future in order to implement the project results in the industrial practice.
Źródło:: Prace Instytutu Lotnictwa; 2011, 11 (220); 5-19
0509-6669
2300-5408
Pojawia się w:: Prace Instytutu Lotnictwa
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: To the problem of child studies in psychological and pedagogical heritage of A. Lazurskiy (early 20th century)
O kwestii badań rozwoju dzieci w psychologicznym i pedagogicznym dziedzictwie a. Lazurskiego (początek xx wieku)
Autorzy:: Leoentyeva, Inna
Powiązania:: https://bibliotekanauki.pl/articles/964142.pdf
Data publikacji:: 2014
Wydawca:: Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:: A. Lazurskiy
the identity of a child
schoolchildren
individual characteristics and features
method of natural experiment
psychological characterization.
Opis:: Exploring the nature of a child, the child's personality, individual traits of character as well as peculiarities of formation and development in educational process is one of the main problems of modern pedagogy. The most significant contribution among scientists in the field of study of child and child’s individual features was made by A. Lazurskiy (1874-1917). The author determines that A. Lazurskiy was inclined to employ psychological knowledge in teaching practice and was deeply convinced that upbringing schoolchildren can rely on detailed and planned studies of child nature by means of psychological and pedagogical methods. Subsequently, the author demonstrates that A. Lazurskiy developed a versatile method for a holistic research of the personality of a child in the educational process – the natural experiment, and was the author of "experimental classes" as a valuable educational tools.
Źródło:: Studia Europaea Gnesnensia; 2014, 10; 99-108
2082-5951
Pojawia się w:: Studia Europaea Gnesnensia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: Assessment of the functioning of quality mon-itoring systemin steelworkbased on the BOST method
Autorzy:: Borkowski, S.
Sygut, P.
Powiązania:: https://bibliotekanauki.pl/articles/111666.pdf
Data publikacji:: 2015
Wydawca:: Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:: BOST method
correlation analysis
characteristics of workers
statistical analysis
series of validity
metoda BOST
analiza korelacji
charakterystyka pracowników
analiza statystyczna
serie ważności
Opis:: This chapter presents the research results on the functioning of the quality control system at the steelworks. The study was conducted using an innovative BOST method. Highlighted the need to improve processes visual inspection as a means of improving the quality of finished products. Based on a survey conducted among employees of the production factors have been identified which require improvement process in question.
Źródło:: Production Engineering Archives; 2015, 8, 3; 14-17
2353-5156
2353-7779
Pojawia się w:: Production Engineering Archives
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: Mikrozmienność charakterystyk metrologicznych termo- i higrometrycznych urządzeń i układów pomiarowych w automatycznych stacjach meteorologicznych Państwowej Służby Hydrologiczno - Meteorologicznej
Micro-variability of characteristics of thermo- and hygrometric circuits in automatic meteorological stations of the State Hydrological-Meteorological Service (PSHM)
Autorzy:: Różdżyński, K.
Powiązania:: https://bibliotekanauki.pl/articles/158475.pdf
Data publikacji:: 2013
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:: niestabilność
dryft charakterystyk meteorologicznych stacji automatycznych
metody weryfikacji danych meteorologicznych
instability
drift characteristics of automatic meteorological station
method of verification meteorological data
Opis:: Przedstawiono wyniki badań zjawiska mikrozmienności charakterystyk, pojawiającego się w niektórych obwodach pomiarowych automatycznych stacji meteorologicznych. Opracowano trzy postępowania, oparte na metodzie pomiarów porównawczych i metodach analizy statystycznej, dla detekcji, oceny oraz przybliżonej kompensacji skutków tych zjawisk. Uzyskano przybliżone obrazy rozwoju procesu mikrozmienności. Postępowania mogą być wykorzystane dla celów analizy jakości danych. Opracowana metodologia została zweryfikowana na 96 rocznych szeregach czasowych o objętości około 0,7 mln par danych.
Results of complex research of phenomena and process of micro-variability of characteristics occurring in thermometric and hygrometric measurement circuits of automatic meteorological stations are presented in the study. Three independent procedures based on the application of the comparative method and statistical analysis enable detecting, evaluating and compensating approximately the effects of the said phenomena and processes. The procedures provided approximate but coherent images of the process of micro-variability and can be used for the purpose of data quality analysis, also in the operational mode. The methodology of detecting and defining the micro-variability processes was verified on 96 annual time series, 1-hour thermometric and hygrometric data of total volume of ca. 0.7 million data pairs.
Źródło:: Pomiary Automatyka Kontrola; 2013, R. 59, nr 6, 6; 562-565
0032-4140
Pojawia się w:: Pomiary Automatyka Kontrola
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 15.

Tytuł:: Experimental estimation of wear resistance of polyamide composites, reinforced by carbon and glass fibres used in metal-polymer gearings
Autorzy:: Chernets, Myron
Kindrachuk, Myroslav
Kornienko, Anatolii
Yurchuk, Alina
Powiązania:: https://bibliotekanauki.pl/articles/1837921.pdf
Data publikacji:: 2020
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:: method for determining the characteristics
functions of wear resistance
reinforced polyamide
dispersed glass fibres
dispersed carbon fibres
metal-polymer gears
Opis:: The method of model triboexperimental studies to determine the basic mathematical model parameters of materials wear resistance at sliding friction is considered. The quantitative relative experimental characteristics of wear resistance of glass fibre and carbon fibre reinforced polyamide used in metal-polymer gear couple have been determined. Wear resistance functions of these functional polymeric composites have been established as the basic ones in the tribokinetic mathematical model of material wear for sliding friction conditions. Also, according to the conducted researches, wear resistance diagrams were constructed. They may be used as graphical indicators of wear resistance in the required range of specific friction forces. The dependences that connect the characteristic functions of wear resistance of these materials (obtained by the developed mathematical tribokinetic wear model) with linear wear and gearing service life are presented.
Źródło:: Acta Mechanica et Automatica; 2020, 14, 4; 206-210
1898-4088
2300-5319
Pojawia się w:: Acta Mechanica et Automatica
Dostawca treści:: Biblioteka Nauki

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