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Wyświetlanie 1-15 z 15
Tytuł:
Steady-state time-periodic finite element analysis of a brushless DC motor drive considering motion
Autorzy:
Jagieła, M.
Gwóźdź, J.
Powiązania:
https://bibliotekanauki.pl/articles/141576.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
finite elements
brushless machines
inverter drives
steady-state
mathematical modeling
Opis:
This paper aims at providing a framework for comprehensive steady-state time-domain analysis of rotating machines considering motion. The steady-state waveforms of electromagnetic and circuit quantities are computed via iterative solution of the nonlinear field-circuit-and-motion problem with constraints of time periodicity. The cases with forced speed and forced load torque are considered. A comparison of execution times with a conventional time-stepping transient model is carried out for two different machines. The numerical stability of a time-periodic model with forced speed is shown to be worse than that of traditional transient time-stepping one, although the model converges within a reasonable number of iterations. This is not the case if forced load via equation of mechanical balance is accounted for. To ensure convergence of the iterative process the physical equation of motion is replaced by the fixed-point equation. In this way the model delivers time-periodic solutions regarding not only the electromagnetic quantities but also the rotational speed.
Źródło:
Archives of Electrical Engineering; 2015, 64, 3; 471-486
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hot Deformation Activation Energy of Metallic Materials Influenced by Strain Value
Autorzy:
Schindler, I.
Opěla, P.
Kawulok, P.
Sauer, M.
Rusz, S.
Kuc, D.
Rodak, K.
Powiązania:
https://bibliotekanauki.pl/articles/2049432.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
flow stress curves
steady state
metallic materials
hot deformation activation energy
Opis:
Suitable and complete sets of stress-strain curves significantly affected by dynamic recrystallization were analyzed for 11 different iron, copper, magnesium, titanium or nickel based alloys. Using the same methodology, apparent hot deformation activation energy Qp and Qss values were calculated for each alloy based on peak stress and steady-state stress values. Linear dependence between quantities Qp and Qss was found, while Qp values are on average only about 6% higher. This should not be essential in predicting true stress of a specific material depending on the temperature-compensated strain rate and strain.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 1; 223-228
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Równowaga, nierównowaga i adaptacja. Inspiracje dla gospodarki przestrzennej
Autorzy:
Domański, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/2021549.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steady-state
social learning
economic cycles
self-oganisation
Nauki Humanistyczne i Społeczne
Źródło:
Studia komitetu przestrzennego zagospodarowania kraju PAN; 2018, 183; 57-66
0079-3507
Pojawia się w:
Studia komitetu przestrzennego zagospodarowania kraju PAN
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Przejścia fazowe w czasoprzestrzeni ekonomicznej. Ku sformułowaniu prawa ruchu
Phase Transitions in Economic Time-space. Towards Formulation of the Law of Motion
Autorzy:
Domański, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/2028959.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Organic transition
shift to higher steady-state
transition and optimal growth
transition dynamics
Opis:
This paper presents a mechanism of the phase transition in economic time-space. The author, in particular, identifies various parts of this mechanism and describes their actions. He distinguishes the following parts: a) transition dynamics, b) transition in the process of optimal growth, c) organic transitions, d) transition from lower to higher level of steady-state. The author expects that future deeper inquire in this mechanism will enable formulation of the law of motion of economic time-space.
Źródło:
Studia komitetu przestrzennego zagospodarowania kraju PAN; 2014, 157; 78-90
0079-3507
Pojawia się w:
Studia komitetu przestrzennego zagospodarowania kraju PAN
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
User-centered design of brain-computer interfaces: OpenBCI.pl and BCI Appliance
Autorzy:
Durka, P.
Kuś, R.
Żygierewicz, J.
Michalska, M.
Milanowski, P.
Łabęcki, M.
Sputek, T.
Laszuk, D.
Duszyk, A.
Kruszyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/201581.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
brain-computer interface
BCI
steady-state visual evoked potentials
SSVEP
eyetracker
assistive technologies
Opis:
Brain-Computer Interface (BCI) allows for non-muscular communication with external world, which may be the only way of communication for patients in a locked-in state. This paper presents a complete software framework for BCI, a novel hardware solution for stimuli rendering in BCIs based on Steady State Visual Evoked Potentials (SSVEP), and a univariate algorithm for detection of SSVEP in the EEG time series. OpenBCI is a complete software framework for brain-computer interfaces. Owing to an open license and modular architecture, it allows for flexible implementations of different communication channels in the serial or parallel hybrid mode, minimization of costs and improvements of stability and efficiency. Complete software is freely available from http://openbci.pl. BCI Appliance is a hardware solution that allows for dynamic control of menus with stable generation of stimuli for the SSVEP paradigm. The novelty consists of a design, whereby the LCD screen is illuminated from behind using an array of LEDs. Design pioneers also proposed a new line of thought about the user-centered design of BCI systems: a simple box with one on/off button, minimum embedded software, wireless connections to domotic and EEG acquisition devices, and user-controlled mode switching in a hybrid BCI.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2012, 60, 3; 427-431
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Steady-state analysis for a class of hyperbolic systems with boundary inputs
Autorzy:
Bartecki, K.
Powiązania:
https://bibliotekanauki.pl/articles/229634.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
distributed parameter system
partial differential equation
hyperbolic system
steady-state solution
heat exchanger
Opis:
Results of a steady-state analysis performed for a class of distributed parameter systems described by hyperbolic partial differential equations defined on a one-dimensional spatial domain are presented. For the case of the system with two state variables and two boundary inputs, the analytical expressions for the steady-state distribution of the state variables are derived, both in the exponential and in the hyperbolic form. The influence of the location of the boundary inputs on the steady-state response is demonstrated. The considerations are illustrated with a practical example of a shell and tube heat exchanger operating in parallel- and countercurrent-flow modes.
Źródło:
Archives of Control Sciences; 2013, 23, 3; 295-310
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Examination of the Effect of a Sound Source Location on the Steady-State Response of a Two-Room Coupled System
Autorzy:
Meissner, M.
Powiązania:
https://bibliotekanauki.pl/articles/177058.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
coupled room system
steady-state room response
potential and kinetic energy densities
localization of modes
Opis:
In this paper, the computer modelling application based on the modal expansion method is developed to study the influence of a sound source location on a steady- state response of coupled rooms. In the research, an eigenvalue problem is solved numerically for a room system consisting of two rectangular spaces connected to one another. A numerical procedure enables the computation of shape and frequency of eigenmodes, and allows one to predict the potential and kinetic energy densities in a steady-state. In the first stage, a frequency room response for several source positions is investigated, demonstrating large deformations of this response for strong and weak modal excitations. Next, a particular attention is given to studying how the changes in a source position influence the room response when a source frequency is tuned to a resonant frequency of a strongly localized mode.
Źródło:
Archives of Acoustics; 2011, 36, 4; 761-775
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
ZA-APA with Adaptive Zero Attractor Controller for Variable Sparsity Environment
Autorzy:
Radhika, S.
Chandrasekar, A.
Nirmalraj, S.
Powiązania:
https://bibliotekanauki.pl/articles/1844469.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Zero Attraction APA
sparse channel
convergence
steady state mean square error
variable zero attraction controller
Opis:
The zero attraction affine projection algorithm (ZA-APA) achieves better performance in terms of convergence rate and steady state error than standard APA when the system is sparse. It uses l1 norm penalty to exploit sparsity of the channel. The performance of ZA-APA depends on the value of zero attractor controller. Moreover a fixed attractor controller is not suitable for varying sparsity environment. This paper proposes an optimal adaptive zero attractor controller based on Mean Square Deviation (MSD) error to work in variable sparsity environment. Experiments were conducted to prove the suitability of the proposed algorithm for identification of unknown variable sparse system.
Źródło:
International Journal of Electronics and Telecommunications; 2020, 66, 4; 695-700
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experiments and FE Analyses on Airborne Sound Properties of Composite Structural Insulated Panels
Autorzy:
Wawrzynowicz, A.
Krzaczek, M.
Tejchman, J
Powiązania:
https://bibliotekanauki.pl/articles/177722.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustic properties
composite structural insulated panel
sound insulation
finite element method
steady state analysis
transient analysis
Opis:
Airborne acoustic properties of composite structural insulated panels CSIPs composed of fibre- magnesium-cement facesheets and expanded polystyrene core were studied. The sound reduction ratings were measured experimentally in an acoustic test laboratory composed of two reverberation chambers. The numerical finite element (FEM) model of an acoustic laboratory available in ABAQUS was used and verified with experimental results. Steady-state and transient FE analyses were performed. The 2D and 3D modelling FE results were compared. Different panel core modifications were numerically tested in order to improve the airborne sound insulation of CSIPs.
Źródło:
Archives of Acoustics; 2014, 39, 3; 351-364
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved algorithm for periodic steady-state analysis in nonlinear electromagnetic devices
Autorzy:
Sobczyk, T. J.
Radzik, M.
Powiązania:
https://bibliotekanauki.pl/articles/201260.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electromagnetic devices
steady-state analysis
periodic solutions
analysis in time domain
discrete differential operator
iterative algorithms
Opis:
This paper presents the improved methodology for the direct calculation of steady-state periodic solutions for electromagnetic devices, as described by nonlinear differential equations, in the time domain. A novel differential operator is developed for periodic functions and the iterative algorithm determining periodic steady-state solutions in a selected set of time instants is identified. Its application to steady-state analysis is verified by an elementary example. The modified algorithm reduces the complexity of steady-state analysis, particularly for electromagnetic devices described by high-dimensional nonlinear differential equations.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 5; 863-869
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorithm for determining two-periodic steady-states in AC machines directly in time domain
Autorzy:
Sobczyk, T.J.
Powiązania:
https://bibliotekanauki.pl/articles/141171.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AC machines
steady state analysis
two-periodic solutions
analysis in time domain
discrete differential operator
iterative algorithms
Opis:
This paper describes an algorithm for finding steady states in AC machines for the cases of their two-periodic nature. The algorithm enables to specify the steady-state solution identified directly in time domain despite of the fact that two-periodic waveforms are not repeated in any finite time interval. The basis for such an algorithm is a discrete differential operator that specifies the temporary values of the derivative of the twoperiodic function in the selected set of points on the basis of the values of that function in the same set of points. It allows to develop algebraic equations defining the steady state solution reached in a chosen point set for the nonlinear differential equations describing the AC machines when electrical and mechanical equations should be solved together. That set of those values allows determining the steady state solution at any time instant up to infinity. The algorithm described in this paper is competitive with respect to the one known in literature an approach based on the harmonic balance method operated in frequency domain.
Źródło:
Archives of Electrical Engineering; 2016, 65, 3; 575-583
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Review of numerical models of cavitating flows with the use of the homogeneous approach
Autorzy:
Niedźwiedzka, A.
Schnerr, G. H.
Sobieski, W.
Powiązania:
https://bibliotekanauki.pl/articles/239953.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sheet cavitation
cloud cavitation
homogeneous models
steady-state
unsteady
hydrofoil
venturi
cylinder
model jednorodny
stan stabilny
stan ustalony
niestacjonarny
hydropłat
Opis:
The focus of research works on cavitation has changed since the 1960s; the behaviour of a single bubble is no more the area of interest for most scientists. Its place was taken by the cavitating flow considered as a whole. Many numerical models of cavitating flows came into being within the space of the last fifty years. They can be divided into two groups: multifluid and homogeneous (i.e., single-fluid) models. The group of homogenous models contains two subgroups: models based on transport equation and pressure based models. Several works tried to order particular approaches and presented short reviews of selected studies. However, these classifications are too rough to be treated as sufficiently accurate. The aim of this paper is to present the development paths of numerical investigations of cavitating flows with the use of homogeneous approach in order of publication year and with relatively detailed description. Each of the presented model is accompanied by examples of the application area. This review focuses not only on the list of the most significant existing models to predict sheet and cloud cavitation, but also on presenting their advantages and disadvantages. Moreover, it shows the reasons which inspired present authors to look for new ways of more accurate numerical predictions and dimensions of cavitation. The article includes also the division of source terms of presented models based on the transport equation with the use of standardized symbols.
Źródło:
Archives of Thermodynamics; 2016, 37, 2; 71-88
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of Hopf bifurcation sets of a chemicalreactors by two-parameter continuation method
Autorzy:
Berezowski, Marek
Powiązania:
https://bibliotekanauki.pl/articles/185121.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chemical reactor
Hopf bifurcation
thank reactor
bifurcation diagram
steady state
stability
dynamics
reaktor chemiczny
Rozwidlenie Hopfa
diagram bifurkacji
stan stabilny
stabilność
dynamika
Opis:
A two-parameter continuation method was developed and shown in the form of an example, allowingdetermination of Hopf bifurcation sets in a chemical reactor model. Exemplary calculations weremade for the continuous stirred tank reactor model (CSTR). The set of HB points limiting the rangeof oscillation in the reactor was determined. The results were confirmed on the bifurcation diagramof steady states and on time charts. The method is universal and can be used for various models ofchemical reactors.
Źródło:
Chemical and Process Engineering; 2020, 41, 3; 221--227
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of novel discrete differential operator of periodic function to study electromechanical interactions
Autorzy:
Sobczyk, T. J.
Radzik, M.
Powiązania:
https://bibliotekanauki.pl/articles/201412.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electromechanical system
steady state analysis
periodic solutions
analysis in time domain
discrete differential operator
iterative algorithms
system elektromechaniczny
analiza stanu ustalonego
rozwiązania okresowe
analiza w dziedzinie czasu
dyskretny operator różniczkowania
algorytm iteracyjny
Opis:
This paper investigates an algorithm for finding steady-states in electromechanical systems for the cases of their periodic nature. The algorithm enables to specify the steady-state solution identified directly in time domain. The basis for such an algorithm is a discrete differential operator that specifies the values of the first derivative of the periodic function in the selected set of points on the basis of the values of that function in the same set of points. It creates algebraic equations describing the steady-state solution for the nonlinear differential equations describing electromechanical systems. In this paper, the direct time-domain approach is tested for the simple converter considering. The algorithm used in this paper is competitive with respect to the one known in literature an approach based on the harmonic balance method operated in frequency domain.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 5; 645-653
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative assesment of steady-state pipeline gas flow models
Analiza porównawcza modeli przepływu gazu w rurociągu w stanach ustalonych
Autorzy:
Chaczykowski, M.
Osiadacz, A.
Powiązania:
https://bibliotekanauki.pl/articles/963887.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
pipeline gas flow
steady-state flow model
convective term
kinetic energy term
design flow equation
GERG 2004 application
transport rurociągowy
ustalony przepływ gazu
człon konwekcyjny
człon energii kinetycznej
równanie przepływu
metoda GERG 2004
Opis:
One-dimensional, non-isothermal flow of gas in a straight pipe has been considered to predict pressure and temperature profiles along the horizontal pipeline under steady-state conditions. Selected analytical models for the simplified calculation of these profiles are evaluated on the basis of the numerical solution of the accurate model, which incorporates the convective term in the momentum equation and the kinetic energy term in the energy equation, while treating the enthalpy as a function of pressure and temperature. For closure of the system of the conservation equations, the GERG 2004 equation of state was chosen. In order to present the discrepancies introduced by the models, the results of the numerical and analytical solutions are compared with the field data. The results show that in the case of the high pressure gas transmission system, the effects of the convective term in the momentum equation and the kinetic energy term in the energy equation are negligible for pipeline pressure and temperature calculation accuracies. It also indicates that real gas effects play an important role in the temperature distribution along the pipeline and cannot be neglected from the calculation when approximate analytical equations are used.
W artykule analizowano jednowymiarowy, nieizotermiczny przepływ gazu w stanie ustalonym w celu określenia zmian ciśnienia i temperatury w poziomym gazociągu. Wyniki uproszczonych obliczeń za pomocą wybranych modeli analitycznych zostały porównane z wynikami obliczeń uzyskanych za pomocą numerycznego całkowania modelu dokładnego, zawierającego człon konwekcyjny w równaniu pędu oraz człon energii kinetycznej w równaniu energii, jednocześnie przyjmując entalpię jako funkcję ciśnienia i temperatury. W celu zamknięcia układu równań zachowania zastosowano równanie stanu zgodnie z metodą GERG 2004. Dla przedstawienia niedokładności związanych z zastosowaniem różnych modeli, przeprowadzono weryfikację wyników na zbiorze danych rzeczywistych. Wyniki pokazują, że w przypadku systemów przesyłowych wysokiego ciśnienia, wpływ członu konwekcyjnego w równaniu pędu oraz członu energii kinetycznej w równaniu energii jest pomijalny z punktu widzenia dokładności obliczeń wartości ciśnienia i temperatury w gazociągu. Ponadto, wyniki pokazują, że prawidłowy opis właściwości gazu rzeczywistego odgrywa ważną rolę w obliczeniach zmian temperatury wzdłuż gazociągu i powinien być stosowany w przypadku przybliżonych metod analitycznych.
Źródło:
Archives of Mining Sciences; 2012, 57, 1; 23-38
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-15 z 15

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