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    Wyświetlanie 1-27 z 27
    Tytuł:
    Dynamical properties of a modified chaotic Colpitts oscillator with triangular wave non-linearity
    Autorzy:
    Suresh, Rasappan
    Sathish Kumar, Kumaravel
    Regan, Murugesan
    Niranjan Kumar, K. A.
    Narmada Devi, R.
    Obaid, Ahmed J.
    Powiązania:
    https://bibliotekanauki.pl/articles/27312004.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    chaos
    Colpitts oscillator
    Lyapunov exponent
    diffusion
    stability
    synchronization
    triangular wave non-linearity
    Opis:
    The purpose of this paper is to introduce a new chaotic oscillator. Although different chaotic systems have been formulated by earlier researchers, only a few chaotic systems exhibit chaotic behaviour. In this work, a new chaotic system with chaotic attractor is introduced for triangular wave non-linearity. It is worth noting that this striking phenomenon rarely occurs in respect of chaotic systems. The system proposed in this paper has been realized with numerical simulation. The results emanating from the numerical simulation indicate the feasibility of the proposed chaotic system. More over, chaos control, stability, diffusion and synchronization of such a system have been dealt with.
    Źródło:
    Archives of Control Sciences; 2023, 33, 1; 25--53
    1230-2384
    Pojawia się w:
    Archives of Control Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comprehensive circumscribing of non-linearity cases of a water supply system with smooth flow control
    Autorzy:
    Orłowski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/241404.pdf
    Data publikacji:
    2006
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    flow reducing valve
    non-linearity of system
    pressure reducing valve
    steady flow
    variable frequency drives
    water supply system
    Opis:
    The descriptions found in the literature, of cases of even relatively strong non-linearity of the water supply systems, as well as their mathematical treatment, are rare and incomplete. They refer mainly to the non-linearity with respect to smooth flow control components (for instance, to the operation of pressure reducing valves (PRV), flow reducing valves (FRV) and pumps with motors equipped with smooth rotational speed control - variable frequency drives (VFD)). The article proposes a formally correct method of a comprehensive solution of the above non-linearity cases based on successive simulations with some dynamic analysis of the sensitivity of the system to the operation of the smooth control components mentioned. An appropriate algorithm controlling the effectiveness of the calculations secures correct description of the behaviour of the system for an arbitrary, in practice, method of control of flows, even if all the proposed smooth control methods are used simultaneously. The effects of the use of the solutions presented in mathematical modelling are illustrated by selected results of simulation carried out for an existing water supply system.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2006, 53, 1; 7-30
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Non-linearity on pull-out test of cohesive soil using low tensile strengths of geogrids
    Autorzy:
    Widodo, S.
    Ibrahim, A. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/115809.pdf
    Data publikacji:
    2014
    Wydawca:
    Fundacja na Rzecz Młodych Naukowców
    Tematy:
    pull-out test
    tensile strength
    geogrid
    ITD
    non-linear
    Opis:
    Influence of geosynthetics inserted into cohesive granular soil was obviously investigated using geosynthetics-soil-interaction-testing device (ITD). Observations were already made during undertaking pull-out test, and then the results revealed that a correlation between shear stress and normal stress exhibits non-linear behaviour. In this paper, three approaches of trend-lines namely linear, logarithmic, and polynomial were compared. From analysis, polynomial trend line gave the best correlation among others. The final equation is very important part when estimating more accurate values of cohesion and friction angle design purpose.
    Źródło:
    Challenges of Modern Technology; 2014, 5, 1; 34-37
    2082-2863
    2353-4419
    Pojawia się w:
    Challenges of Modern Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Method for ship’s rolling period prediction with regard to non-linearity of GZ curve
    Autorzy:
    Wawrzyński, W.
    Krata, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/281346.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    ship natural roll period
    GZ approximation
    rolling prediction
    safety against capsizing
    Opis:
    The paper deals with the problem of prediction of the rolling period. A special emphasis is put on the practical application of the new method for rolling period prediction with regard to non-linearity of the GZ curve. The one degree-of-freedom rolling equation is applied with using the non-linear stiffness moment and linear damping moment formulas. A number of ships are considered to research the discrepancies between the pending GM-based IMO- -recommended method and the results of conducted numerical simulations performed for a wide range of operational loading conditions. Since the research shows some drawbacks of the IMO formula for the ship rolling period, a new formula is worked out and proposed instead.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2016, 54, 4; 1329-1343
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of noise and non-linearity of I-V characteristics of positive temperature coefficient chip thermistors
    Autorzy:
    Sita, Z.
    Sedlakova, V.
    Majzner, J.
    Sedlak, P.
    Sikula, J.
    Grmela, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/220721.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    PTC chip sensors
    noise spectroscopy
    I-V characteristic non-linearity
    quality evaluation
    Opis:
    Noise spectroscopy and I-V characteristic non-linearity measurement were applied as diagnostic tools in order to characterize the volume and contact quality of positive temperature coefficient (PTC) chip sensors and to predict possible contact failure. Correctly made and stable contacts are crucial for proper sensing. I-V characteristics and time dependences of resistance were measured for studied sensors and, besides the samples with stable resistance value, spike type resistance fluctuation was observed for some samples. These spikes often disappear after about 24 hours of voltage application. Linear I-V characteristics were measured for the samples with stable resistance. The resistance fluctuation of burst noise type was observed for some samples showing the I-V characteristic dependent on the electric field orientation. We have found that the thermistors with high quality contacts had a linear I-V characteristic, the noise spectral density is of 1/f type and the third harmonic index is lower than 60 dB. The samples with poor quality contacts show non-linear I-V characteristics and excess noise is given by superposition of g-r and 1/fn type noises, and the third harmonic index is higher than 60 dB.
    Źródło:
    Metrology and Measurement Systems; 2013, 20, 4; 635-644
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelling Suppression of Non-Linear Machine Vibration
    Autorzy:
    Vondrich, J.
    Thöndel, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/971125.pdf
    Data publikacji:
    2009
    Wydawca:
    Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
    Tematy:
    Matlab
    non-linearity
    vibration
    machine
    Opis:
    In this paper, the coupled non-linear differential equations of the model of machine as non-linear dynamical two degree of freedom vibrating system including cubic non-linearity are solved. The system consists of the main system and the absorber. Consider the non-linearity dynamical vibrating system as a model machine, which is compiled of a driven motor, gearbox and mechanisms with elastic and damping parts and driven parts. The absorber is used to control the main system vibrations when subjected to external excitation force. This system represents many applications in machine tools, ultrasonic cutting process, etc. Optimum working conditions for the absorber are by the same frequencies ω = ω2 [1] of the action force F =F0 sinω t and main mass m1. The effects of different parameters of the system are studied numerically with Matlab.
    Źródło:
    Journal of Machine Engineering; 2009, 9, 2; 45-50
    1895-7595
    2391-8071
    Pojawia się w:
    Journal of Machine Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ wysokości długu publicznego na koszty jego obsługi
    Impact of the Level of Public Debt on its Service Costs
    Autorzy:
    Brzozowski, Michał
    Powiązania:
    https://bibliotekanauki.pl/articles/956883.pdf
    Data publikacji:
    2013
    Wydawca:
    Akademia Leona Koźmińskiego w Warszawie
    Tematy:
    interest rate
    public debt
    Non-linearity
    Opis:
    Purpose: The article aims at analyzing the functional form of the relation between the level of public debt and the government bond yields in both developed and developing countries. A surge in public indebtedness following the financial crisis in 2008-2010 undermined the credibility of sovereigns in the credit markets. As a result, the government bond yields have risen, thus amplifying the problem of rapidly expanding public debts. The purpose of the article is to estimate the threshold value of government debt above which its service costs rapidly increase. Methodology: The relation between the 10-year government bond real interest rate and the level of debt is investigated with the use of spline regression with cubic splines. The regression model is estimated using annual data for 66 countries that spans between the years 1980-2010. An additional analysis is conducted for the last decade and after splitting the sample into high-income and catching-up countries. Findings: In the sample that covers all countries and the whole 1980-2010 period no relation between the level of debt and interest rate has been detected. In the years 2001-2010 the threshold value of debt above which the real interest rate starts to grow rapidly is estimated to be around 150% of GDP in catching-up countries and about 110% of GDP in high-income countries. Research implications: An analysis of the impact of fiscal policy on the level of interest should take into account the likely non-linearity of the relationship. Originality: Spline regression has not yet been used in the analysis of the relation between debt and interest rate.
    Źródło:
    Management and Business Administration. Central Europe; 2013, 21, 2(121); 49-63
    2084-3356
    Pojawia się w:
    Management and Business Administration. Central Europe
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Practical aspects of testing superconducting electromagnets by the capacitor discharge method taking into account the non-linearity of circuit parameters
    Autorzy:
    Michna, Michał
    Wilk, Andrzej
    Wołoszyk, Marek
    Ziółko, Michał
    Galla, Stanisław
    Szwangruber, Piotr
    Powiązania:
    https://bibliotekanauki.pl/articles/24202739.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    diagnostic
    discharge method
    superconducting electromagnets
    Opis:
    The article presents selected issues related to the development and testing of the diagnostics systems dedicated for superconducting electromagnets. The systems were con- structed to assess the production quality of superconducting electromagnets of the SIS100 synchrotron, a new accelerator being built as part of the Facility of Antiproton and Ion Re- search (FAIR). One of the systems is used for automatic checking of electrical connection parameters and the continuity of electric circuits. The role of the second device is to assess the quality of winding insulation and to estimate circuit parameters of electromagnet coils using the capacitor discharge method. The work presents measurements and analysis of current and voltage waveforms acquired during discharges on a magnet coil simulator and on the SIS100 main dipole electromagnet.
    Źródło:
    Archives of Electrical Engineering; 2023, 72, 2; 323--338
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Variations in developmental patterns across pragmatic features
    Autorzy:
    Li, Qiong
    Powiązania:
    https://bibliotekanauki.pl/articles/780817.pdf
    Data publikacji:
    2016
    Wydawca:
    Uniwersytet im. Adama Mickiewicza w Poznaniu
    Tematy:
    L2 pragmatic development; variations
    longitudinal perspective
    non-linearity
    Opis:
    Drawing on the findings of longitudinal studies in uninstructed contexts over the last two decades, this synthesis explores variations in developmental patterns across second language (L2) pragmatic features. Two synthesis questions were addressed: (a) What are the variations in developmental patterns across pragmatic features?, and (b) What are the potential explanations for the variations? In response to the first question, previous studies showed that L2 pragmatic development is a non-linear, dynamic process, with developmental paces varying across pragmatic features (Ortactepe, 2013; Taguchi, 2010, 2011, 2012; Warga & Scholmberger, 2007). These studies revealed that some aspects of pragmatic features (e.g., semantic strategies of speech acts) develop faster than others (e.g., lexical features such as mitigators). In response to the second question, three potential explanations were identified to account for the developmental variations: (a) language-related, (b) situation-dependent, and (c) learner-related explanations, with three subcategories for the language-related explanation: (a) the functions of pragmatic features, (b) the frequency of availability of target features, and (c) the similarity and difference between languages with respect to the target feature.
    Źródło:
    Studies in Second Language Learning and Teaching; 2016, 6, 4; 587-617
    2083-5205
    2084-1965
    Pojawia się w:
    Studies in Second Language Learning and Teaching
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Odbiorca medialny w erze Web 2.0
    The media recipient in the Web 2.0 era
    Autorzy:
    Maćkiewicz, Jolanta
    Powiązania:
    https://bibliotekanauki.pl/articles/31339533.pdf
    Data publikacji:
    2023
    Wydawca:
    Uniwersytet Gdański. Wydawnictwo Uniwersytetu Gdańskiego
    Tematy:
    media
    odbiorca
    internet
    nielinearność
    multimodalność
    recipient
    non-linearity
    multimodality
    Opis:
    Artykuł poświęcony jest nakreśleniu sylwetki nowego odbiorcy czy raczej użytkownika mediów. Zakłada się, że przyczyniły się do tego nowe technologie, a raczej nowy sposób używania tych technologii (Web 2.0). Nowy sposób używania to nieograniczony wybór treści, a także czasu, miejsca i sposobu docierania do nich, recepcja nielinearna i powierzchowna, interaktywność, możność modyfikowania i tworzenia przekazów. Nowy odbiorca jest głównie powierzchowny, niecierpliwy i impulsywny, odbierający nielinearnie i kompleksowo, nastawiony bardziej na obraz niż na słowo, aktywny.
    The article is devoted to outlining the profile of a new media recipient, or rather a media user. It is assumed that new technologies, or rather a new way of using these technologies (Web 2.0), contributed to this. The new way of using means unlimited choice of content as well as time, place and way of reaching it; non-linear and superficial reception; interactivity; the possibility of modifying and creating messages. The new user is mainly superficial, impatient and impulsive, receiving non-linearly and comprehensively, more image-oriented than word-oriented, active.
    Źródło:
    Media Biznes Kultura; 2023, 1(14); 9-17
    2451-1986
    2544-2554
    Pojawia się w:
    Media Biznes Kultura
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermal strength analysis of a steel bolted connection under bolt loss conditions
    Autorzy:
    Grzejda, Rafał
    Powiązania:
    https://bibliotekanauki.pl/articles/2087009.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    bolted connection
    thermal strength
    non-linearity
    finite element method
    preload
    Opis:
    The aim of the paper is to analyse an exemplary bolted connection under the conditions of loss of bearing capacity of some fasteners in the connection. The presented tests are numerical and concern an asymmetric bolted connection. The joined elements in the connection were modelled as 3D finite elements, and the fasteners were treated as hybrid models consisting of rigid heads and nuts, and flexible beams between them. The bolted connection was first preloaded according to six different tensioning orders using a standardised force. After all bolts were tensioned, the selected bolts were removed, simulating bolt damage. The connection was then tested for external loads with temperatures ranging from 20 to 600°C. The influence of loosening the connection on the load in the remaining bolts at the operational stage of the connection was investigated. The calculation results were compared with the test results for a healthy bolted connection. It was shown that the bearing capacity of the connection in the damaged state decreased by 13%.
    Źródło:
    Eksploatacja i Niezawodność; 2022, 24, 2; 269--274
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On determination of inductances for circuit models of AC machines
    Autorzy:
    Sobczyk, T. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/141479.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    electric machines
    modelling magnetic non-linearity
    dynamic inductances
    non-linear inductances
    Opis:
    The paper discuss a problem of determination of inductances for AC machine windings when saturation of magnetic circuit is not neglected. For such cases, computation of magnetic field distribution in the machine magnetic circuit is a starting point for post processing procedures leading to various values, among others the co-energy in a given area and linkage fluxes of windings. This paper shows how to determine winding inductances in a nonlinear magnetic circuit from these two values and also how to compute directly nonlinear inductances. Problem is not trivial because such inductances are not uniquely determined as for linear case. In the paper a definition of nonlinear inductances is proposed which makes the choice unique.
    Źródło:
    Archives of Electrical Engineering; 2013, 62, 3; 487-496
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Non-linearity and the Purchasing Power Parity Hypothesis for Exchange Rate JPY/USD
    Nieliniowość i hipoteza parytetu siły nabywczej pieniądza dla kursu walutowego JPY/USD
    Autorzy:
    Bruzda, Joanna
    Koźliński, Tomasz
    Powiązania:
    https://bibliotekanauki.pl/articles/907591.pdf
    Data publikacji:
    2005
    Wydawca:
    Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
    Tematy:
    purchasing power parity
    forecasting exchange rates
    non-linear adjustment
    non-linear error correction models
    Opis:
    In the paper we verify the purchasing power parity (PPP) hypothesis for the exchange rate JPY/USD for different time periods and price indexes. We build several forecasting models for this exchange rate including some non-linear specifications, for example the univariate BL-GARCH model and fundamental VEC models based on a long run equilibrium relationship. We have found that under some specific conditions the PPP hypothesis does hold. An adjustment process towards a long run equilibrium turned out to be of a non-linear nature. However, the impact of this adjustment on short-run dynamics of the exchange rate has a linear error correction form.
    W artykule przedstawiamy wyniki weryfikacji hipotezy parytetu sity nabywczej pieniądza dla kursu walutowego JPY/USD dla różnych okresów i różnych indeksów cenowych. Prezentujemy kilka modeli prognostycznych dla tego kursu, włączając pewne specyfikacje nieliniowe, jak np. jednowymiarowy model BL-GARCH oraz fundamentalne modele VEC, oparte na zależności w długookresowym położeniu równowagi. Wyniki empiryczne wskazują, że przy pewnych specyficznych warunkach hipoteza PPP zachodzi. Proces dostosowania do długookresowego położenia równowagi okazuje się mieć postać nieliniową. Jednakże wpływ tego dostosowania na krótkookresową dynamikę kursu walutowego JPY/USD ma formę liniowej korekty błędem.
    Źródło:
    Acta Universitatis Lodziensis. Folia Oeconomica; 2005, 192
    0208-6018
    2353-7663
    Pojawia się w:
    Acta Universitatis Lodziensis. Folia Oeconomica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Resonance of a structure with soil elastic waves released in non-linear hysteretic soil upon unloading
    Autorzy:
    Kowalczyk, Piotr
    Powiązania:
    https://bibliotekanauki.pl/articles/2172887.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    finite element modelling
    earthquake engineering
    wave propagation
    soil dynamics
    soil non-linearity
    Opis:
    High-frequency motion is often observed in small-scale experimental works carried out in flexible containers under simplified seismic loading conditions when single harmonic sine input motions are introduced at the base of a soil specimen. The source of the high-frequency motion has often been sought in experimental inaccuracies. On the other hand, the most recent numerical studies suggested that high-frequency motion in the steady-state dynamic response of soil subjected to harmonic excitation can also be generated as a result of soil elastic waves released in non-linear hysteretic soil upon unloading. This work presents an example of a finite element numerical study on seismic soil–structure interaction representative of an experimental setup from the past. The results show how high-frequency motion generated in soil in the steady-state response, apparently representative of soil elastic waves, affects the steady-state response of a structure, that is, it is presented how the structure in the analysed case resonates with the soil elastic waves. The numerical findings are verified against the benchmark experimental example to indicate similar patterns in the dynamic response of the structure.
    Źródło:
    Studia Geotechnica et Mechanica; 2022, 44, 4; 253--266
    0137-6365
    2083-831X
    Pojawia się w:
    Studia Geotechnica et Mechanica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Reclaiming Queer Time: Queer Temporalities in Ali Smith’s "How to be Both"
    Autorzy:
    Navalón-Guzmán, Corpus
    Powiązania:
    https://bibliotekanauki.pl/articles/28407292.pdf
    Data publikacji:
    2023
    Wydawca:
    Uniwersytet Przyrodniczo-Humanistyczny w Siedlcach
    Tematy:
    Queer Temporalities
    Queer Time
    Non-linearity
    Queer Narrative
    Queer Studies
    LGBTQIA+ Identity
    Opis:
    This article examines the different manifestations of alternative temporalities in Ali Smith’s Goldsmiths Award novel How to be Both (2014). My argument is that the novel ‘queers’ understandings of time in two significant ways: by highlighting new possibilities of narrative structure that challenge linear conceptions of time and by questioning regulated notions of developmental temporalities in terms of progression from childhood to heteronormative adulthood. Hence, by drawing on the compelling framework of queer temporalities, the main goal of this article is to analyze the mechanisms deployed by Ali Smith to generate unprecedented configurations of queer time.
    Źródło:
    Forum for Contemporary Issues in Language and Literature; 2023, 4; 68-78
    2391-9426
    Pojawia się w:
    Forum for Contemporary Issues in Language and Literature
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Droppers’ stiffness influence on dynamic interaction between the pantograph and railway catenary
    Autorzy:
    Bryja, Danuta
    Hyliński (Popiołek), Adam
    Powiązania:
    https://bibliotekanauki.pl/articles/215741.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Kolejnictwa
    Tematy:
    railway catenary
    pantographs
    droppers’ slackening
    geometrical non-linearity
    vibration simulation
    validation of simulation method
    Opis:
    Droppers connecting the contact wire and messenger wire of the railway catenary are characterized by zero or negligible compressive stiffness, hence they become slack under compression that is similar to bars’ buckling. The paper presents a numerical analysis of the influence of droppers slackening phenomenon on the dynamic interaction between the pantograph and catenary. The analysis is based on a simulation method presented by the authors in previous papers, in which the catenary is modelled as a complex cable system. In this paper, the simulation method is modified by introducing the residual compressive stiffness of droppers that is assumed as a given percent of tensile stiffness. Modification leads to geometrically non-linear equations of motion of the pantograph-catenary system. Two different algorithms for solving the problem of non-linearity are proposed, in both of them the Newmark numerical integration method is applied. Results of dynamic response simulations performed for different values of residual compressive stiffness of droppers are presented and compared. It is shown that the contact wire does not cooperate with the messenger wire in a large area around the pantograph when the compressive stiffness of droppers is assumed zero. As a result, the pantograph moving at high speed induces severe vibrations of the catenary. It is also shown that droppers should be designed to have the residual compressive stiffness equal to at least one percent of their tensile stiffness. This is sufficient to ensure an appropriate cooperation between messenger wire and contact wire, which is demonstrated by simulation results fulfilling requirements given in the standard PN-EN 50318: 2002.
    Źródło:
    Problemy Kolejnictwa; 2019, 183; 89-98
    0552-2145
    2544-9451
    Pojawia się w:
    Problemy Kolejnictwa
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparative Measurements on Loudspeaker Distortion: Current vs. Voltage Control
    Autorzy:
    Meriläinen, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/176516.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    current driving
    current control
    loudspeaker distortion
    current distortion
    inductance non-linearity
    voice coil former
    Opis:
    Modulation and harmonic distortion produced by ordinary moving-coil direct-radiator drive units are measured under current control and voltage control. A realistic two-tone test signal is used to investigate the detrimental effect of the voice coil electromotive forces on the voltage-to-current conversion that is critical with voltage control. Dramatic improvements in distortion performance are obtained with current control. Current nonlinearities in voltage-controlled speakers are shown to be the dominant source of modulation and odd harmonic distortions at signal frequencies above the fundamental resonance region. Currents in conductive voice coil formers also seem to be significant sources of distortion; with current control and non-conductive formers, odd harmonics and related modulation products virtually vanished in the upper midrange.
    Źródło:
    Archives of Acoustics; 2017, 42, 1; 71-81
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Frictional heating during sliding of two semi-spaces with arbitrary thermal nonlinearity
    Autorzy:
    Och, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/386528.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
    Tematy:
    frictional heating
    arbitrary thermal non-linearity
    thermosensitive materials
    temperatura tarcia
    materiały termoczułe
    nieliniowość termiczna
    Opis:
    Analytical and numerical solution for transient thermal problems of friction were presented for semi limited bodies made from thermosensitive materials in which coefficient of thermal conductivity and specific heat arbitrarily depend on the temperature (materials with arbitrary non-linearity). With the constant power of friction assumption and imperfect thermal contact linearization of nonlinear problems formulated initial-boundary thermal conductivity, using Kirchhoff transformation is partial. In order to complete linearization, method of successive approximations was used. On the basis of obtained solutions a numerical analysis of two friction systems in which one element is constant (cermet FMC-845) and another is variable (grey iron ChNMKh or aluminum-based composite alloy AL MMC) was conducted.
    Źródło:
    Acta Mechanica et Automatica; 2014, 8, 4; 204-208
    1898-4088
    2300-5319
    Pojawia się w:
    Acta Mechanica et Automatica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Hybridisation of Mel Frequency Cepstral Coefficient and Higher Order Spectral Features for Musical Instruments Classification
    Autorzy:
    Bhalke, D. G.
    Rama Rao, C. B.
    Bormane, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/176497.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    feature extraction
    MFCC
    HOS
    bispectrum
    bicoherence
    non-linearity
    non-Gaussianity
    CPNN
    zero crossing rate (ZCR)
    Opis:
    This paper presents the classification of musical instruments using Mel Frequency Cepstral Coefficients (MFCC) and Higher Order Spectral features. MFCC, cepstral, temporal, spectral, and timbral features have been widely used in the task of musical instrument classification. As music sound signal is generated using non-linear dynamics, non-linearity and non-Gaussianity of the musical instruments are important features which have not been considered in the past. In this paper, hybridisation of MFCC and Higher Order Spectral (HOS) based features have been used in the task of musical instrument classification. HOS-based features have been used to provide instrument specific information such as non-Gaussianity and non-linearity of the musical instruments. The extracted features have been presented to Counter Propagation Neural Network (CPNN) to identify the instruments and their family. For experimentation, isolated sounds of 19 musical instruments have been used from McGill University Master Sample (MUMS) sound database. The proposed features show the significant improvement in the classification accuracy of the system.
    Źródło:
    Archives of Acoustics; 2016, 41, 3; 427-436
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Finite Element Modelling of a Pair of Flexible Elements Contact Preloaded and Externally Loaded with an Arbitrary Force
    Autorzy:
    Grzejda, Rafał
    Powiązania:
    https://bibliotekanauki.pl/articles/103248.pdf
    Data publikacji:
    2020
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    contact joint
    non-linearity
    finite element method
    preload
    połączenie stykowe
    nieliniowość
    metoda elementów skończonych
    wstępne ładowanie
    Opis:
    In the paper, the numerical tests of the contact of a pair of flexible elements were presented. The non-linear phenomena occurring in the contact zone of two elements have been considered separately for the assembly and operational condition of the joint. The physical and mathematical models of the contact joint created using the finite element method were proposed. The contact joint is treated as a system composed of the subsystems: two of them are joined elements and the third one is the contact layer between the elements. The calculations results for the selected contact joint were given.
    Źródło:
    Advances in Science and Technology. Research Journal; 2020, 14, 3; 118-124
    2299-8624
    Pojawia się w:
    Advances in Science and Technology. Research Journal
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A multimode approach to geometrically non-linear forced vibration of beams carrying point masses
    Autorzy:
    Fakhreddine, Hatim
    Adri, Ahmed
    Chajdi, Mohcine
    Rifai, Said
    Benamar, Rhali
    Powiązania:
    https://bibliotekanauki.pl/articles/328557.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
    Tematy:
    geometrical non-linearity
    forced vibrations
    multimode approach
    stress distribution
    point mass
    nieliniowość geometryczna
    drgania wymuszone
    rozkład naprężeń
    Opis:
    The present work deals with the geometrically non-linear forced vibrations of beams carrying a concentric mass under different end conditions. Considering the axial strain energy and expanding the transverse displacement in the form of a finite series of spatial functions, the application of Hamilton's principle reduces the vibration problem to a non-linear algebraic system solved by an approximate method developed previously. In order to validate the approach, comparisons are made of the present solutions with those previously obtained by the finite element method. Focus is made here on the analysis of the non-linear stress distribution in the beam with an attached mass. The non-linear forced deflection shapes and their corresponding curvatures are presented for different magnitudes of the attached mass, different excitation levels and different vibration amplitudes.
    Źródło:
    Diagnostyka; 2020, 21, 4; 23-33
    1641-6414
    2449-5220
    Pojawia się w:
    Diagnostyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Non-linearity of the contact layer between elements joined in a multi-bolted connection and the preload of the bolts
    Nieliniowość warstwy stykowej między elementami łączonymi w połączeniu wielośrubowym a napięcie wstępne śrub
    Autorzy:
    Grzejda, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/132898.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Naukowe Silników Spalinowych
    Tematy:
    multi-bolted connection
    engine cylinder head
    engine block
    assembly
    połączenie wielośrubowe
    głowica
    blok silnika
    montaż
    Opis:
    The paper presents modeling and calculations of multi-bolted connections at the assembly stage on an example of the engine cylinder head-block connection. The physical model of the connection was introduced as a combination of three subsystems: the set of bolts, the joined element and the contact layer between the joined element and the rigid support. The finite element method (FEM) was used for the modeling. Bolts were replaced with hybrid elements. The joined element was modeled with spatial finite elements. The Winkler model of the contact layer has been taken into consideration. The truth of the theorem has been examined, according to which non-linearity of the contact layer has a negligible impact on the final values of the bolt forces in the case of sequential preloading of the multi-bolted connection. The results of the calculations of a selected multi-bolted connection have been compared with the experimental results.
    Przedstawiono modelowanie i obliczenia połączeń wielośrubowych na etapie montażu, na przykładzie połączenia głowicy z blokiem silnika. Wprowadzono model fizyczny połączenia zbudowany z trzech podukładów: zbioru śrub, elementu łączonego i warstwy stykowej między elementem łączonym a nieodkształcalną ostoją. Do modelowania wykorzystano metodę elementów skończonych (MES). Śruby zastąpiono elementami hybrydowymi. Element łączony zamodelowano za pomocą przestrzennych elementów skończonych. Warstwę stykową potraktowano jako ciało Winklera. Zbadano prawdziwość tezy, według której nieliniowość warstwy stykowej ma znikomy wpływ na końcowe wartości sił w śrubach w przypadku połączenia wielośrubowego napinanego wstępnie kolejno dokręcanymi śrubami. Wyniki obliczeń wybranego połączenia wielośrubowego porównano z wynikami badań doświadczalnych.
    Źródło:
    Combustion Engines; 2016, 55, 2; 3-8
    2300-9896
    2658-1442
    Pojawia się w:
    Combustion Engines
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Determination of Bolt Forces and Normal Contact Pressure Between Elements in the System With Many Bolts for its Assembly Conditions
    Autorzy:
    Grzejda, Rafał
    Powiązania:
    https://bibliotekanauki.pl/articles/101884.pdf
    Data publikacji:
    2019
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    multi-bolted system
    non-linearity
    FE-modelling
    Winkler contact model
    preload
    system wielośrubowy
    nieliniowość
    modelowanie FE
    model kontaktowy Winklera
    napięcie wstępne
    Opis:
    The paper put forward a thesis that modelling dissymmetric non-linear multi-bolted connections as a system is possible. Modelling of the systems composed of four subsystems on the assembly state was presented. These subsystems included: a couple of joined elements (a flange and a support), a contact layer between them, and bolts. The physical model of the system was described considering the tightening of bolts according to a specific sequence. In this model: the flange and the support were built using spatial finite elements, the contact layer was formed as the non-linear Winkler model, and the bolts were replaced with simplified models made of flexible beams. The calculation model which can be applied to determine the changes in bolt forces, as well as in the normal contact pressure between the joined elements during the tightening of the system and at its end, was presented. The results of sample calculations for the selected multi-bolted system were shown.
    Źródło:
    Advances in Science and Technology. Research Journal; 2019, 13, 1; 116-121
    2299-8624
    Pojawia się w:
    Advances in Science and Technology. Research Journal
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dynamic displacement analysis of reinforced concrete deep beams made of high strength concrete. Part II, Dynamic displacement analysis of reinforced concrete deep beams made of high strength C200 grade concrete
    Analiza dynamicznego przemieszczenia tarcz żelbetowych z betonu wysokiej wytrzymałości. Cz. 2, Analiza dynamicznego przemieszczenia tarczy żelbetowej z betonu wysokiej wytrzymałości klasy C200
    Autorzy:
    Cichorski, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/208481.pdf
    Data publikacji:
    2018
    Wydawca:
    Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
    Tematy:
    mechanika konstrukcji
    konstrukcje żelbetowe
    tarcze
    obciążenie dynamiczne
    nieliniowość fizyczna
    mechanics of structures
    reinforced concrete structures
    deep beams
    dynamic load
    physical non-linearity
    Opis:
    The dynamic load displacements were analysed of rectangular concrete deep beams made of very high strength concrete, grade C200, including an evaluation of the physical non-linearity of the construction materials: concrete and reinforcing steel. The analysis was conducted using the method presented in [1]. The numerical calculation results are presented with particular reference to the displacement state of rectangular concrete deep beams. A comparative analysis was conducted on the effect of the high-strength concrete and the steel of increased strength on a class C200 concrete deep beam versus the results produced in [10] for a class C100 concrete deep beam.
    W pracy przedstawiono analizę stanu przemieszczenia prostokątnych tarcz żelbetowych wykonanych z betonu bardzo wysokiej wytrzymałości klasy C200 obciążonych dynamicznie z uwzględnieniem fizycznych nieliniowości materiałów konstrukcyjnych: betonu i stali zbrojeniowej. Analiza została przeprowadzona na podstawie metody zaprezentowanej w pracy [1]. Przedstawiono wyniki rozwiązań numerycznych ze szczególnym uwzględnieniem stanu przemieszczenia tarczy. Przeprowadzono analizę porównawczą wpływu betonu wysokiej wytrzymałości i stali podwyższonej wytrzymałości na tarczy poprzez porównanie uzyskanych wyników dla tarczy z betonu klasy C200 z wynikami uzyskanymi dla tarczy żelbetowej wykonanej z betonu klasy C100 zamieszczonymi w pracy [10].
    Źródło:
    Biuletyn Wojskowej Akademii Technicznej; 2018, 67, 2; 27-50
    1234-5865
    Pojawia się w:
    Biuletyn Wojskowej Akademii Technicznej
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Confidence intervals for large non-centrality parameters
    Autorzy:
    Inacio, Sonia
    Oliveira, Manuela
    Mexia, João
    Powiązania:
    https://bibliotekanauki.pl/articles/729746.pdf
    Data publikacji:
    2015
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    asymptotic linearity
    non-centrality parameters
    highly significant
    F tests
    measure relevance
    Opis:
    We use asymptotic linearity to derive confidence intervals for large non-centrality parameters. These results enable us to measure relevance of effects and interactions in multifactors models when we get highly statistically significant the values of F tests statistics. We show how to use our approach by considering two sets of data as application examples.
    Źródło:
    Discussiones Mathematicae Probability and Statistics; 2015, 35, 1-2; 45-56
    1509-9423
    Pojawia się w:
    Discussiones Mathematicae Probability and Statistics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Przyczynek do metod nieparametrycznej identyfikacji dynamiki obiektów z wykorzystaniem charakterystyk w dziedzinie czasu
    The Contribution to Non-Parametric Identification Methods Based on the Time- Domain System representation
    Autorzy:
    Żuchowski, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/152663.pdf
    Data publikacji:
    2010
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    identyfikacja nieparametryczna
    charakterystyki w dziedzinie czasu
    test liniowości
    nonparametric identification
    time-domain system representation
    test for system linearity
    Opis:
    Wykres zależności Y(X), w której Y(t) jest ustaloną odpowiedzią liniowego obiektu dynamicznego na sygnał pobudzający X(t)=Asin(??t) uzyskany dla niewielkich pulsacji ? niesie informacje o typie dynamiki obiektu zawarte w stosunku odpowiednich, charakterystycznych odcinków tego wykresu. Istnieje przy tym możliwość sprawdzenia, czy model dynamiki zawiera pochodne ułamkowego rzędu i czy jest modelem liniowym. Artykuł prezentuje ideę tej metody identyfikacji.
    The graph of relationship determined by the dynamic linear object response to the signal gives information on the type of the object dynamics and the values of its parameters. The parametric identification methods for dynamics with use of such relationships have been known for a long time. However, it appears that for appropriately low values of the pulsation, certain characteristic segments of the graph give particular information on the type of the linear object dynamics, and thus they can be used for nonparametric identification. It allows widening the range of applying such a method by new components, useful for practice. For instance, it enables: to check in a simple way if the dynamics is described by differential equations of fractional order, to test the linearity of those equations, to eliminate the influence of disturbances in measuring channels at the input and output of the tested object. The dynamic properties of the measuring instruments used for tests do not influence the identification results on condition that they are identical for both channels. In case of nonlinearity of the identified object dynamics, this method enables determining the type and parameters of the equivalent linearised model. The paper presents the idea of this method and discusses it in details.
    Źródło:
    Pomiary Automatyka Kontrola; 2010, R. 56, nr 8, 8; 915-917
    0032-4140
    Pojawia się w:
    Pomiary Automatyka Kontrola
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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