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    Wyświetlanie 1-39 z 39
    Tytuł:
    About need for using nonlinear models in vibroacoustic diagnostics
    O konieczności stosowania w diagnostyce wibroakustycznej modeli nieliniowych
    Autorzy:
    Dąbrowski, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/329646.pdf
    Data publikacji:
    2008
    Wydawca:
    Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
    Tematy:
    efekt nieliniowy
    diagnostyka wibroakustyczna
    nonlinear effect
    vibroacoustic diagnostic
    Opis:
    The paper discussed the thesis that in vibroacoustic diagnostics using the nonlinear mathematical model is necessary. Natural specification of machine degradation is the frequency response function change and "additional" inputs related to defects remain usually as self-exited vibrations, which require the application of nonlinear description. Very often a new machine can be described with an adequate accuracy by a linear model. During exploitation certain nonlinear disturbances related to wear and tear - occur. Thus, an observation of nonlinear effects allows solving a diagnostic task.
    W artykule przedyskutowano potrzebę stosowania w diagnostyce wibroakustycznej modeli nieliniowych. Naturalnym opisem degradacji maszyny jest zmiana funkcji odpowiedzi częstotliwościowej, a "dodatkowe" wymuszenia związane z uszkodzeniami pozostają z reguły jako drgania samowzbudne, co z założenia wymaga zastosowania opisu nieliniowego. Bardzo często nową maszynę możemy opisać z dobrą dokładnością modelem liniowym. W trakcie eksploatacji pojawiają się i wzrastają nieliniowe zaburzenia związane ze zużyciem. Tym samym obserwacja efektów nieliniowych pozwala na rozwiązanie zadania diagnostycznego.
    Źródło:
    Diagnostyka; 2008, 3(47); 153-156
    1641-6414
    2449-5220
    Pojawia się w:
    Diagnostyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Propagation of solitary wave in non-uniform fiber system with high-order nonlinear effects
    Autorzy:
    Xiao, Y.
    Zhang, J.
    Zhang, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/173308.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    solitary wave
    coupled higher-order nonlinear Schrödinger equation
    high-order nonlinear effect
    Opis:
    The ultra-short pulse propagation in a non-uniform fiber system is investigated based on the variable coefficient coupled higher-order nonlinear Schrödinger equation with the dispersion gain and nonlinear gain terms. By using the ansatz method and the split-step Fourier method, we get the exact solitary wave solution, with which the transmission process of the solitary wave is studied. Furthermore we obtain the stability of the solitary wave under finite initial perturbations. The interaction between two neighboring solitary waves is also studied.
    Źródło:
    Optica Applicata; 2018, 48, 2; 273-284
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Extended elliptic mild slope equation incorporating the nonlinear shoaling effect
    Autorzy:
    Xiao, Q. L.
    Li, Ch. H.
    Fu, X. Y.
    Wang, M. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/258718.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    nonlinear dispersion relation
    nonlinear shoaling coefficient
    extended elliptic mild slope equation
    surf zone
    wave transformation
    Opis:
    The transformation during wave propagation is significantly important for the calculations of hydraulic and coastal engineering, as well as the sediment transport. The exact wave height deformation calculation on the coasts is essential to near-shore hydrodynamics research and the structure design of coastal engineering. According to the wave shoaling results gained from the elliptical cosine wave theory, the nonlinear wave dispersion relation is adopted to develop the expression of the corresponding nonlinear wave shoaling coefficient. Based on the extended elliptic mild slope equation, an efficient wave numerical model is presented in this paper for predicting wave deformation across the complex topography and the surf zone, incorporating the nonlinear wave dispersion relation, the nonlinear wave shoaling coefficient and other energy dissipation factors. Especially, the phenomenon of wave recovery and second breaking could be shown by the present model. The classical Berkhoff single elliptic topography wave tests, the sinusoidal varying topography experiment, and complex composite slopes wave flume experiments are applied to verify the accuracy of the calculation of wave heights. Compared with experimental data, good agreements are found upon single elliptical topography and one-dimensional beach profiles, including uniform slope and step-type profiles. The results indicate that the newly-developed nonlinear wave shoaling coefficient improves the calculated accuracy of wave transformation in the surf zone efficiently, and the wave breaking is the key factor affecting the wave characteristics and need to be considered in the nearshore wave simulations.
    Źródło:
    Polish Maritime Research; 2016, S 1; 44-51
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Propagation of Spatial Solitons with Nonlinear Kerr Effect in Thermal Medium
    Autorzy:
    Gharaati, A.
    Elahi, P.
    Cari, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047846.pdf
    Data publikacji:
    2007-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    42.65.Sf
    42.65.Tg
    42.65.Wi
    Opis:
    In this paper, the propagation and behavior of spatial solitons of inhomogeneous nonlinear Schrödinger equation in thermal medium will be investigated analytically. The theoretical model is established by considering the change of refractive index of medium due to heat deposition of entrance beam. The soliton like solution in such thermal medium was derived. The effect of input pump power and beam radius on the behavior of solitons will be studied finally.
    Źródło:
    Acta Physica Polonica A; 2007, 112, 5; 891-896
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of nonlinear effects in diagnostics of composite structures
    Analiza zjawisk nieliniowych w diagnozowaniu konstrukcji kompozytowych
    Autorzy:
    Dziurdź, J.
    Skórski, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/329216.pdf
    Data publikacji:
    2009
    Wydawca:
    Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
    Tematy:
    zjawisko nieliniowe
    diagnostyka
    kompozyt węglowy
    światłowodowa siatka Bragga
    nonlinear effect
    diagnostics
    carbon fibre composite
    fiber Bragg grating (FBG)
    Opis:
    The following text presents possibilities of the analysis of nonlinear effects in research of high-durability of carbon fibre composites, on the example of the sailing ship mast. The special attention was returned on the possibility using of modern techniques of measurement deformations with optical fibre sensor with the change of the light wavelength - Fibre Bragg Grating. Analyse the diagnostic problem of condition in consequence dynamics analysis of composite structure.
    Tekst przedstawia możliwości analizy zjawisk nieliniowych w badaniach dynamiki wysokowytrzymałych struktur z kompozytów węglowych, na przykładzie masztu jachtu żaglowego. Szczególną uwagę zwrócono na możliwość wykorzystania nowoczesnych technik pomiarów odkształceń z czujnikami światłowodowymi ze zmianą długości fali świetlnej - siatki Bragga. Przeanalizowano problem diagnozowania stanu na podstawie analizy dynamiki konstrukcji kompozytowych.
    Źródło:
    Diagnostyka; 2009, 1(49); 63-66
    1641-6414
    2449-5220
    Pojawia się w:
    Diagnostyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nonlinear PTO effect on performance of vertical axisymmetric wave energy converter using semi-analytical method
    Autorzy:
    Liu, M.
    Liu, H.
    Zheng, X.
    Chen, H.
    Wang, L.
    Zhang, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/258878.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    wave energy converter (WEC)
    power take-off (PTO)
    capture width ratios
    analytical method
    eigen function
    Opis:
    The wave energy, as a clean and non-pollution renewable energy sources, has become a hot research topic at home and abroad and is likely to become a new industry in the future. In this article, to effectively extract and maximize the energy from ocean waves, a vertical axisymmetric wave energy converter (WEC) was presented according to investigating of the advantages and disadvantages of the current WEC. The linear and quadratic equations in frequency-domain for the reactive controlled single-point converter property under regular waves condition are proposed for an efficient power take-off (PTO). A method of damping coefficients, theoretical added mass and exciting force are calculated with the analytical method which is in use of the series expansion of eigen functions. The loads of optimal reactive and resistive, the amplitudes of corresponding oscillation, and the width ratios of energy capture are determined approximately and discussed in numerical results.
    Źródło:
    Polish Maritime Research; 2017, S 3; 49-57
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Arbitrary Order Perturbation Expansion Applied to Steady-State Nonlinear Kerr Effect Relaxations in Coupled AC and DC Weak Fields
    Autorzy:
    Hounkonnou, M. N.
    Ronveaux, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1920935.pdf
    Data publikacji:
    1992-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    33.55.Fi
    05.40.+j
    Opis:
    The steady state response of the nonlinear Kerr effect to a small ac field superimposed on a dc field is analysed using second-order perturbation theory. We justify the truncature effect entailed in solving the infinite set of differential equations that yield the electric polarization and birefringence, and hence draw inferences from the appearance of single and double harmonics as the fundamental frequencies of nonlinear Kerr effect. The addition of small inertial effects in the solution of this phenomenon results in the appearance of a contribution within the master matrix which is proportional to the square of the frequency corresponding to the order of perturbation. The study is based on the Smoluchowski equation of rotational Brownian motion.
    Źródło:
    Acta Physica Polonica A; 1992, 82, 3; 425-441
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nonreciprocal Effect in Magnetooptical-Nonlinear Waveguide
    Autorzy:
    Gniadek, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/2014909.pdf
    Data publikacji:
    2001-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    42.65.Wi
    Opis:
    The nonreciprocal phase shift of TM waves guided by the linear thin film sandwiched between magnetooptic semi-infinite substrate and nonlinear Kerr-type semi-infinite cladding has been investigated theoretically and numerically. With the help of the conservation energy law for TM modes in nonlinear waveguide the dispersion relation without a knowledge of the nonlinear field profile has been derived. The dependence of the nonreciprocal behaviour of the guided waves in terms of the local intensity at the film-nonlinear cladding boundary is discussed. Introducing a nonlinear material into magnetooptic waveguide structure leads to interesting applications for a new class of integrated devices which combine magnetooptic and nonlinear effects.
    Źródło:
    Acta Physica Polonica A; 2001, 99, 1; 25-31
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of External Electric Field on Time of Nonlinear Optical Reorientational Effect in Nematics
    Autorzy:
    Bajdecki, W. K.
    Karpierz, M. A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2035684.pdf
    Data publikacji:
    2003
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    42.65.-k
    42.70.Df
    Opis:
    Nonlinear reorientation phenomena in nematic liquid crystals cause extremely large refractive index changes. However, this effect is relatively slow and the determination of the time necessary to appearing or disappearing of the nonlinear effect is an important issue. In this work we present measurements of the time of increasing the nematics reorientation induced by the light beam passing through the liquid crystalline layer. The influence of external low-frequency electric field suppressing reorientation is also reported. The obtained results describing relations between time and optical power of light as well as between time and external electric field intensity are in good agreement with theory.
    Źródło:
    Acta Physica Polonica A; 2003, 103, 2-3; 187-193
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of Nonlinear Elasticity on Interband and Intersubband Transition Energies in GaN/AlN Superlattices
    Autorzy:
    Łepkowski, S. P.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047688.pdf
    Data publikacji:
    2007-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Pt
    62.20.Dc
    77.65.Ly
    77.65.-j
    Opis:
    We present a theoretical study of the effect of nonlinear elasticity on interband and intersubband transition energies in wurtzite GaN/AlN superlattices. The effect of nonlinear elasticity is considered by taking into account the changes of elastic constants caused by the intrinsic hydrostatic pressure, originating from lattice misfit between constituents of the superlattice. We show that the influence of the effect of the nonlinear elasticity on the interband and intersubband transition energies in the GaN/AlN superlattices depends crucially on the strain state of structures, in particular on the in-plane lattice constant of the buffer or the substrate. For the superlattices strained to AlGaN buffers with small aluminum concentrations, the effect of nonlinear elasticity increases significantly the interband transition energy and decreases the intersubband transition energy. For the superlattices strained to AlGaN buffers with large aluminum concentrations, the effect of nonlinear elasticity leads to a decrease in the interband transition energy and an increase in the intersubband transition energy.
    Źródło:
    Acta Physica Polonica A; 2007, 112, 2; 315-319
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the contribution of the quadratic electrooptic effect to the nonlinear response proportional to the fourth power of modulating field
    Pozorny elektrooptyczny efekt czwartego rzędu mający swoje źródło w kwadratowym efekcie elektrooptycznym
    Autorzy:
    Izdebski, M.
    Kucharczyk, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/296563.pdf
    Data publikacji:
    2007
    Wydawca:
    Politechnika Łódzka. Wydawnictwo Politechniki Łódzkiej
    Tematy:
    kwadratowy współczynnik elektrooptyczny
    elektrooptyczny efekt czwartego rzędu
    quadratic electrooptic effect
    fourth-order electrooptic effect
    Opis:
    It is shown that the fourth-order electrooptic effect cannot be measured without a background of the contribution that is proportional to the square of the quadratic electrooptic coefficient. The contribution manifests on the fourth power of the modulating field and may be calculated. Thus, if the contribution is found to be comparable with the measured fourth-order electrooptic response, this apparent fourth-order effect should be taken into account in the interpretation ofthe results of the measurement.
    Pokazano, że prawdziwemu efektowi elektrooptycznemu czwartego rzędu zawsze towarzyszy efekt pozorny, mający swoje źródło w efekcie kwadratowym. Dotychczas zaniedbywany wkład pozornego efektu można obliczyć i jeśli jest on porównywalny z mierzoną odpowiedzią przypisywaną efektowi elektrooptycznemu czwartego rzędu, należy go uwzględnić przy interpretacji wyników pomiarów.
    Źródło:
    Scientific Bulletin. Physics / Technical University of Łódź; 2007, 28; 9-12
    1505-1013
    2449-982X
    Pojawia się w:
    Scientific Bulletin. Physics / Technical University of Łódź
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On a nonlinear and chaotic non-ideal vibrating system with shape memory alloy (SMA)
    O nieliniowym, chaotycznym i nieidealnym układzie drgającym z elementami wykazującymi efekt pamięci kształtu
    Autorzy:
    Piccirillo, V.
    Balthazar, J. M.
    Pontes, B. R. Jr.
    Felix, J. L. P.
    Powiązania:
    https://bibliotekanauki.pl/articles/280905.pdf
    Data publikacji:
    2008
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    pamięć kształtu
    chaos
    efekt Sommerfelda
    shape memory
    nonlinear dynamics
    Sommerfeld effect
    Opis:
    In this paper, we present nonlinear dynamic behaviour of a system which consists of a mass connected to a rigid support by a shape memory alloy (SMA) element and a damper. In order to disturb the system, a DC motor with limited power supply is connected to the mass, causing an interaction between the vibrating structure and the energy source. The SMA element is characterised using a one-dimensional phenomenological constitutive model, based on the classical Devonshire theory. We analyse the non-ideal system in form of two coupled nonlinear differential equations. Some interesting nonlinear phenomena as the Sommerfeld effect and nonlinear resonance including periodic, chaotic and hyperchaotic regime are presented.
    W pracy przedstawiono opis dynamiki nieliniowego układu złożonego z masy połączonej ze sztywnym podłożem za pośrednictwem elementu z pamięcią kształtu i tłu- mikiem. W celu realizacji wymuszenia w układzie zastosowano silnik prądu stałego z ograniczonym poborem mocy, który pobudza do ruchu masę, tworząc w ten sposób sprzężenie mechaniczne pomiędzy układem drgającym a źródłem energii. Element z pamięcią kształtu opisano za pomocą jednowymiarowego modelu fenomenologicznego opartego na teorii Devenshire’a. Przeanalizowano rozważany nieidealny układ opisany dwoma sprzężonymi nieliniowymi równaniami ruchu. Zaobserwowano i opisano interesujące zjawiska nieliniowe w postaci efektu Sommerfelda i nieliniowego rezonansu w zakresie drgań okresowych, chaotycznych i hiperchaotycznych.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2008, 46, 3; 597-620
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nonlinear Load and RLC Pulse Shaping Surge Generator Models in Simulation Environment
    Autorzy:
    Edirisinghe, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/412021.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Nonlinear load
    surge generator
    surge protection
    loading effect
    Opis:
    The present study was performed in order to understand how a nonlinear load affects the characteristics of the RLC pulse shaping surge generator waveforms under simulation studies. The obtained results were compared when analytical equations were used as source models for both 1.2/50 s voltage & 8/20 s current impulses. Three circuit models; Capacitor Bank generator, Combination waveform generator and Schaffner generator were evaluated under nonlinear loads varied from 10Ω to 106 Ω for voltage impulses and for current impulses it was from 10-4 Ω to 1 Ω. As it can perceive from the analysis, delay time, rise time and FWHM remain unchanged throughout the tested impedance range when used model equations as generator sources. It was found that for voltage impulses, these values were 4.95 μs, 1.20 μs and 81.8 μs respectively. For current impulses, these values were 16.2 μs, 8.02 μs and 20.7 μs respectively. However results obtained for generator circuit models shows that delay time, rise time and FWHM deviated from above values up to maximum of 35.15 %, 106.67 % & 115.16 % respectively for voltage impulses. For current impulses these deviations were up to maximum of 79.63 %, 48.75 % & 39.61 % respectively. The deviations were due to influence caused by the nonlinear load to the generator circuit parameters and effective internal impedance.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 17, 3; 334-347
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Surface Impedance Boundary Conditions applied to solving nonlinear electrodynamic systems
    Autorzy:
    Pawłowski, S.
    Plewako, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/141489.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    nonlinear electrodynamics
    Surface Impedance Boundary Conditions
    harmonic fields
    quasi-stationary fields
    skin effect
    Opis:
    The paper presents a method for solving electromagnetic field problems by applying impedance boundary conditions for systems including conducting bodies of nonlinear magnetic properties in an excited harmonic field. Three types of impedance boundary conditions were derived. A procedure for computing surface impedance based on the transfer matrix is proposed. This procedure has been tested by comparing computational results to calculations where time function distortions were considered, and to the experimental data.
    Źródło:
    Archives of Electrical Engineering; 2017, 66, 2; 433-446
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Constrained controllability of nonlinear stochastic impulsive systems
    Autorzy:
    Karthikeyan, S.
    Balachandran, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/907784.pdf
    Data publikacji:
    2011
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    sterowalność zupełna
    system nieliniowy
    system stochastyczny
    complete controllability
    nonlinear stochastic system
    impulsive effect
    Banach contraction principle
    Opis:
    This paper is concerned with complete controllability of a class of nonlinear stochastic systems involving impulsive effects in a finite time interval by means of controls whose initial and final values can be assigned in advance. The result is achieved by using a fixed-point argument.
    Źródło:
    International Journal of Applied Mathematics and Computer Science; 2011, 21, 2; 307-316
    1641-876X
    2083-8492
    Pojawia się w:
    International Journal of Applied Mathematics and Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Geometrically nonlinear vibrations of thin visco-elastic periodic plates on a foundation with damping: non-asymptotic modelling
    Autorzy:
    Jędrysiak, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/280289.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    thin visco-elastic periodic plates
    nonlinear vibrations
    effect of microstructure size
    analytical tolerance modelling
    Opis:
    The objects under consideration are thin visco-elastic periodic plates with moderately large deflections. Geometrically nonlinear vibrations of these plates are investigated. In order to take into account the effect of microstructure size on behaviour of these plates a non- -asymptotic modelling method is proposed. Using this method, called the tolerance modelling, model equations with constant coefficients involving terms dependent on the microstructure size can be derived. In this paper, only theoretical considerations of the problem of nonlinear vibrations of thin visco-elastic periodic plates resting on a foundation with damping are presented.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2016, 54, 3; 945-961
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An effect of electrokinetics phenomena on nonlinear wave propagation in bubbly liquids
    Autorzy:
    Panahov, G.
    Abbasov, E.
    Bakhtiyarov, S.
    Museibli, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/2106456.pdf
    Data publikacji:
    2021
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    fala nieliniowa
    ciecz musująca
    potencjał elektryczny
    nonlinear waves
    bubbly liquids
    electrokinetic phenomena
    perturbation
    electric potential
    Opis:
    A study of nonlinear waves in liquid-gas mixtures with the consideration of internal effects is an important problem of both the fundamental and the applied fluid mechanics. Investigation of nonlinear waves in the gas-liquid mixtures with allowance for internal effects is an important task of both fundamental and applied fluid mechanics. These problems often arise in industrial processes such as oil and gas production, hydrocarbons pipeline transportation, gas-saturated fluids flow in pipelines, etc. In this work, we investigate the effect of the internal electric field on the nonlinear wave propagation in a bubbly liquid. Numerical simulations have been conducted to study the nonlinear waves described by the nonlinear Burgers-Korteweg-de Vries equation. The numerical simulations showed that the electrokinetic processes significantly affect the wave propagation process. The amplitude of the waves gradually decreases when the size of the gas bubble is decreasing and the electrical potential increases. A good agreement of obtained results with our previous predictions is found.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2021, 26, 3; 177--186
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An all optical majority gate using nonlinear photonic crystal based ring resonators
    Autorzy:
    Poursaleh, Amir
    Andalib, Alireza
    Powiązania:
    https://bibliotekanauki.pl/articles/175120.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    majority gate
    photonic crystal
    Kerr effect
    ring resonator
    Opis:
    Optical logics will play a crucial role in the next generation all optical data processing networks. Therefore an all optical majority gate will be designed by using nonlinear photonic crystal ring resonators. For realizing the proposed structure we need three nonlinear resonant rings. In order to make nonlinear resonant rings, we used chalcogenide glass as the dielectric material for the dielectric rods. The output port of the proposed structure will be active only when two or three logic input ports are active. The rise and fall time values of the proposed structure are about 2 and 1 ps, respectively. The total footprint of the proposed structure is about 1287 μm2.
    Źródło:
    Optica Applicata; 2019, 49, 3; 487-498
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of capillarity on fourth order nonlinear evolution equation for two Stokes wave trains in deep water in the presence of air flowing over water
    Autorzy:
    Dhar, A. K.
    Mondal, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/265884.pdf
    Data publikacji:
    2015
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    nonlinear evolution equation
    surface capillary gravity wave
    stability
    grawitacja
    fala kapilarna
    równania nieliniowe
    Opis:
    Fourth order nonlinear evolution equations, which are a good starting point for the study of nonlinear water waves, are derived for deep water surface capillary gravity waves in the presence of second waves in which air is blowing over water. Here it is assumed that the space variation of the amplitude takes place only in a direction along which the group velocity projection of the two waves overlap. A stability analysis is made for a uniform wave train in the presence of a second wave train. Graphs are plotted for the maximum growth rate of instability wave number at marginal stability and wave number separation of fastest growing sideband component against wave steepness. Significant improvements are noticed from the results obtained from the two coupled third order nonlinear Schrödinger equations.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2015, 20, 2; 267-282
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The effect of added point masses on the geometrically non-linear vibrations of SCSC rectangular plates
    Autorzy:
    Hamdani, Mustapha
    El Kadiri, Mounia
    Benamar, Rhali
    Powiązania:
    https://bibliotekanauki.pl/articles/2096183.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
    Tematy:
    SCSC rectangular plates
    added mass
    nonlinear free vibration
    nonlinear forced vibration
    swobodne drgania nieliniowe
    płyta prostokątna
    nieliniowe drgania wymuszone
    Opis:
    A point mass added to a plate may have a significant effect on its linear and nonlinear dynamics, including frequencies, mode shapes and the forced response to external loading. In the present paper, a simply supported clamped simply supported clamped rectangular plate (SCSCRP) carrying a point mass is examined. The expressions for the kinetic, linear and non-linear strain energies are derived by taking into account the effect of the added mass on the kinetic energy and the effect of the membrane forces induced by the non-linearity on the strain energy. The discretization of these expressions makes the mass tensor, the linear and non-linear rigidity tensors appear in a non-linear algebraic multimode amplitude equation, the iterative solution of which permit to obtain, in the neighborhood of the first non-linear mode, the basic SCSCRP function amplitude dependent contribution coefficients. Nonlinear frequency response functions have been obtained for the first time, based on an iterative numerical solution in each case of the associated complete set of nonlinear algebraic equations. Such new results are useful for a better qualitative understanding allowing an optimal dynamic design of the rectangular plates with added masses.
    Źródło:
    Diagnostyka; 2022, 23, 2; art. no. 2022206
    1641-6414
    2449-5220
    Pojawia się w:
    Diagnostyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dynamical jump attenuation in a non-ideal system through a magnetorheological damper
    Autorzy:
    Piccirillo, V.
    Tusset, A. M.
    Balthazar, J. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/280364.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    magnetorheological damper
    Sommerfeld effect
    nonlinear dynamics
    Opis:
    This paper is concerned with the Sommerfeld effect (Jump phenomena) attenuation in an non-ideal mechanical oscillator connected with an unbalanced motor excitation with a limited power supply (non-ideal system) using a magnetorheological damper (MRD). The dynamical response of systems with MRD presents different behavior due to their nonlinear characteristic. MRD nonlinear response is associated with adaptive dissipation related to their hysteretic behavior. The Bouc-Wen mathematical model is used to represent the MRD behavior. Numerical simulations show different aspects about the Sommerfeld effect, illustrating the influence of the different electric current applied in the MRD to control the force developed by this damper.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2014, 52, 3; 595-604
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the nonlocal interaction range for stability of nanobeams with nonlinear distribution of material properties
    Autorzy:
    Jankowski, Piotr
    Powiązania:
    https://bibliotekanauki.pl/articles/2105997.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
    Tematy:
    nanobeam
    FGM
    nonlocal strain gradient theory
    buckling
    piezoelectric effect
    Opis:
    The present study analyses the range of nonlocal parameters’ interaction on the buckling behaviour of nanobeam. The intelligent nonhomogeneous nanobeam is modelled as a symmetric functionally graded (FG) core with porosity cause nonlinear distribution of material parameters. The orthotropic face-sheets are made of piezoelectric materials. These kinds of structures are widely used in nanoelectromechanical systems (NEMS). The nanostructure model satisfies the assumptions of Reddy third-order beam theory and higher-order nonlocal elasticity and strain gradient theory. This approach allows to predict appropriate mechanical response of the nanobeam regardless of thin or thick structure, in addition to including nano-sized effects as hardening and softening. The analysis provided in the present study focuses on differences in results for nanobeam stability obtained based on classical and nonlocal theories. The study includes the effect of diverse size-dependent parameters, nanobeams’ length-to-thickness ratio and distributions of porosity and material properties through the core thickness as well as external electro-mechanical loading. The results show a dependence of nonlocal interaction range on geometrical and material parameters of nanobeam. The investigation undertaken in the present study provides an interpretation for this phenomenon, and thus aids in increasing awareness of nanoscale structures’ mechanical behaviour.
    Źródło:
    Acta Mechanica et Automatica; 2022, 16, 2; 151--161
    1898-4088
    2300-5319
    Pojawia się w:
    Acta Mechanica et Automatica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Loopshaping of motor torque controller
    Autorzy:
    Sieklucki, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/229950.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    electric drive
    II2 controller
    robust control
    stability region
    parametric optimization
    nonlinear programming
    waterbed effect
    weighted sensitivity
    modulus criterion
    Opis:
    The controller synthesis problem of the motor torque is presented. The tuning of the II2 controller parameters of the electromagnetic motor torque is introduced. The results are obtained by applying the weighted sensitivity method (nominal performance) which is the optimization in H∞ space. The waterbed effect for some weighting functions is presented. The results, which are obtained by a parametric optimization (nonlinear programming), are analysed by the calculations of the stability margins.
    Źródło:
    Archives of Control Sciences; 2013, 23, 2; 213-228
    1230-2384
    Pojawia się w:
    Archives of Control Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Salehs Model of AM/AM and AM/PM Conversions is not a Model without Memory : Another Proof
    Autorzy:
    Borys, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/226188.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Saleh's model of AM/AM
    Saleh's model of AM/PM
    conversions
    power amplifiers
    memory effect
    in-phase representation of nonlinear devices
    quadrature representation of nonlinear devices
    Opis:
    The so-called Saleh's representation for description of the AM/AM and AM/PM conversions, occurring in communication power amplifiers, consists of two expressions that describe them as functions of a real-valued baseband signal modulating the carrier amplitude. It is a common view that this description forms a model without memory. We show here that the above belief is not correct; just the opposite is true. To prove this, we take into account an equivalent description of the Saleh's model called the quadrature model of bandpass nonlinearities and express it in a form of a nonlinear operator. Afterwards, we check whether this operator possesses a zero memory. To this end, we use an appropriate theorem of the nonlinear systems theory. Finally, as a result of this investigation, we observe that the memory of the above operator is nonzero.
    Źródło:
    International Journal of Electronics and Telecommunications; 2017, 63, 1; 73-77
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Designing ultra-fast all-optical full-subtractor using the photonic crystal structure
    Autorzy:
    Pakrai, Forogh
    Soroosh, Mohammad
    Ganji, Jabbar
    Powiązania:
    https://bibliotekanauki.pl/articles/2202769.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    full subtractor
    nonlinear ring resonator
    optical Kerr effect
    photonic crystal
    Opis:
    In this paper, a photonic crystal-based structure for an all-optical full-subtractor has been proposed. The structure includes six nonlinear resonant rings to transmit the incoming optical waves toward the output ports. Using the different radii for nonlinear rods made the possibility of the dropping operation for different amounts of optical intensities. The nonlinear rods are made of a doped-glass with an optical Kerr coefficient of 10–15 m2/W. To calculate the components of the optical waves throughout the structure, the finite-difference time-domain method has been used. The simulation results prove the correct functionality of the proposed structure. Besides, the maximum rise time of the device is equal to 2 ps. The contrast ratio and the area of the structure are around 8.08 dB and 2790 μm2, respectively.
    Źródło:
    Optica Applicata; 2023, 53, 1; 99--109
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Budowa grafów przyczynowo-skutkowych procesów z wykorzystaniem archiwalnych przebiegów sygnałów
    Building cause-effect graph of processes with use of archival signal values
    Autorzy:
    Tabor, Ł.
    Powiązania:
    https://bibliotekanauki.pl/articles/277657.pdf
    Data publikacji:
    2010
    Wydawca:
    Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
    Tematy:
    graf przyczynowo-skutkowy
    diagnostyka
    modelowanie procesów
    obiekt liniowy
    obiekt nieliniowy
    cause-effect graph
    diagnostics
    process modeling
    linear system
    nonlinear system
    Opis:
    W artykule opisano metodę automatycznego tworzenia grafu przyczynowo-skutkowego procesu przemysłowego. Metoda polega na wyszukiwaniu w całym zbiorze zmiennych procesowych takich sygnałów, które związane są pewnymi znanymi zależnościami często występującymi w instalacjach przemysłowych (np. algorytm regulacji PID). Następnie poszukiwane są pary sygnałów o wysokiej wartości współczynników korelacji liniowej Pearsona oraz monotonicznej Spearmana i Kendalla między zmiennymi. Dodatkowo analizowana jest sekwencja rozchodzenia się zaburzeń w instalacji. Na podstawie zdobytych informacji tworzony jest graf przyczynowo-skutkowy opisujący obiekt lub jego część. Przedstawiono efekt działania algorytmu dla dwóch obiektów. Pierwszy składa się z trzech zbiorników z cieczą z regulacją poziomu w jednym z nich. Drugim jest fragment sieci przesyłowej transportującej gaz ziemny na dużym obszarze.
    The paper presents cause-effect graphing method applied to industrial process. Method is based on searching in process dataset such signals, that are tied together by relations often occurring in industrial installations (for example PID algorithm). Subsequently algorithm is looking for pairs of signals having high values of Pearson, Spearman and Kendall correlation coefficients. Additionally sequence of spreading disturbances is analyzed. On the basis of the gathered information case-effect graph that describes analyzed object or its part is build. Effect of described method is presented with two example industrial objects. First is a three tank system. Second is a part of gas network.
    Źródło:
    Pomiary Automatyka Robotyka; 2010, 14, 11; 65-68
    1427-9126
    Pojawia się w:
    Pomiary Automatyka Robotyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Photoinduced piezoelectric and elastic effects in the 2-cyclooctylamino-5-nitropyridine–C70 complexes
    Autorzy:
    Kamanina, N. V.
    Owsik, J.
    Rusek, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/174933.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    nonlinear media
    piezooptical effect
    2-cyclooctylamino-5-nitropyridine (COANP)
    fullerene
    interaction mechanisms
    Opis:
    We have observed the piezoelectric and elastooptic effects for the 2-cyclooctylamino-5-nitropyridine complex, chromophore doped by an inter-molecular acceptor – fullerene C70. The discovered features may be used for optically operated piezoelectric triggers, modulators and deflectors. The observed effects are caused by the effective interaction of external light with the polarizable chromophore. As a pumping laser beam we have used both a nanosecond fundamental 1064 nm laser wavelength as well as its second harmonic generation at 532 nm. A principal role in the observed effects play photoinduced anharmonic phonons, effectively contributing to the output effect.
    Źródło:
    Optica Applicata; 2013, 43, 3; 463-469
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A novel proposal for all-optical XOR/XNOR gate using a nonlinear photonic crystal based ring resonator
    Autorzy:
    Asghari, Mehrnoush
    Moloudian, Gholamhosein
    Hassangholizadeh-Kashtiban, Mahdi
    Powiązania:
    https://bibliotekanauki.pl/articles/173268.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    photonic crystal
    optical logics
    XOR gate
    XNOR gate
    Kerr effect
    Opis:
    Optical logic gates are very important structures required for creating all-optical digital signal processing systems. Optical XOR and XNOR gates can be used for designing optical adders and optical comparators, respectively. In this paper we proposed a novel structure which can be used for simultaneous implementation of optical XOR and XNOR logic gates. The proposed structure was designed using a nonlinear photonic crystal ring resonator. The delay time for XOR and XNOR gates are 1.7 and 3 ps, respectively.
    Źródło:
    Optica Applicata; 2019, 49, 2; 283-291
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The effect of quintic nonlinearity on the investigation of transversely vibrating buckled Euler-Bernoulli beams
    Autorzy:
    Sedighi, H. M.
    Reza, A.
    Zare, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/279371.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    quintic nonlinearity
    He’s max-min approach
    amplitude-frequency formulation
    nonlinear vibration
    buckled beam
    Opis:
    A new formulation of vibrations of the axially loaded Euler-Bernoulli beam with quintic nonlinearity is investigated in the present study. The beam nonlinear natural frequency as a function of the initial amplitude is obtained. In this direction, modern powerful analytical methods namely He’s Max-Min Approach (MMA) and Amplitude-Frequency Formulation (AFF) are employed to approximate the frequency-amplitude relationship of the beam vibrations. Afterwards, it is clearly shown that the first term in the series expansions is sufficient to produce a highly accurate approximation of the nonlinear system. Finally, preciseness of the present analytical procedures is evaluated in contrast with numerical calculation methods.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2013, 51, 4; 959-968
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of viscosity on the far-field diffraction pattern of spatial self-phase modulation
    Autorzy:
    Nibu, A. G.
    Silpa, S. S.
    Ardra, S. N.
    Anisha, M. M.
    Ambika, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/174699.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    self-phase modulation
    nonlinear refractive index
    chlorophyll
    engine oil
    Opis:
    Effect of viscosity of a liquid on the far-field diffraction pattern due to spatial self-phase modulation is investigated. Chlorophyll extract in acetone at different concentrations is used as the low viscous nonlinear samples and commercial engine oils, synthetic and natural. It is also used as high viscous media. In the case of chlorophyll solution, the self-induced diffraction ring pattern in the far-field is a series of circular rings at the beginning; but later it is transformed to half circular symmetry. But for the high viscous engine oils we have observed circular fringes and there is no time dependent structural variation in the pattern. The coefficient of the intensity dependent nonlinear refractive index for all the liquid samples is evaluated.
    Źródło:
    Optica Applicata; 2017, 47, 4; 591-599
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ stężenia salicylanu sodu na właściwości reologiczne wodnego roztworu bromku heksadecylotrimetyloamoniowego
    Effect of sodium salicylate concentration on rheological properties of hexadecylotrimethylammonium bromide aqueous solution
    Autorzy:
    Kostrzewa, M.
    Broniarz-Press, L.
    Wierschem, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2073010.pdf
    Data publikacji:
    2014
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    micele robaczkowe
    stężenie przeciwjonu
    nieliniowa reologia
    micellar solutions
    counterion concentration
    nonlinear rheology
    Opis:
    Przedstawiono wyniki badań właściwości reologicznych wodnego roztworu bromku heksadecylotrimetyloamoniowego, ukierunkowane na analizę krzywych lepkości i naprężenia ścinającego w funkcji stężenia dodatku salicylanu sodu. Badane roztwory wykazują silnie nienewtonowski charakter. Wykazano zmiany wewnątrz struktury spowodowane przepływem ścinającym. Również pomiary oscylacyjne wykazały wpływ stężenia przeciwjonu na strukturę i wielkość sieci micelarnych.
    Studies on rheological properties of hexadecylotrimethylammonium bromide aqueous solutions with addition of sodium salicylate focused on flow and viscosity curves analysis are presented in the paper. The studied solutions revealed strong non-Newtonian properties. It was proven that shear flow caused structural changes in the micellar network. The dynamical measurements showed an influence of counterion concentration on the structure and size of micellar network.
    Źródło:
    Inżynieria i Aparatura Chemiczna; 2014, 5; 353--354
    0368-0827
    Pojawia się w:
    Inżynieria i Aparatura Chemiczna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Tolerance modelling of nonstationary problems of microheterogeneous media and structures
    Autorzy:
    Jędrysiak, J.
    Domagalski, Ł.
    Marczak, J.
    Pazera, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/128176.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    microheterogeneous media
    microheterogeneous structure
    tolerance modelling
    non-stationary problems
    nonlinear vibrations
    microstructure effect
    ośrodki mikroheterogeniczne
    struktury mikroheterogeniczne
    modelowanie tolerancyjne
    problemy niestacjonarne
    drgania nieliniowe
    efekt mikrostruktury
    Opis:
    In this note a certain review of applications of a non-asymptotic modelling approach, called the tolerance modelling, is presented. Some objects and thermomechanical problems are shown, with a general outline of this method and an example of application for nonlinear vibrations of periodic beams.
    Źródło:
    Vibrations in Physical Systems; 2018, 29; 1-23
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The effect of thermal modulation on double diffusive convection in the presence of applied magnetic field and internal heat source
    Autorzy:
    Manjula, S. H.
    Suresh, P.
    Rao, M. G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1839901.pdf
    Data publikacji:
    2021
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    analiza nieliniowa
    płyn newtonowski
    konwekcja
    thermal modulation
    weak nonlinear analysis
    internal heating
    newtonian fluid
    double diffusive convection
    Opis:
    The investigation of thermal modulation on double-diffusive stationary convection in the presence of an applied magnetic field and internal heating is carried out. A weakly nonlinear stability analysis has been performed using the finite-amplitude Ginzburg-Landau model. This finite amplitude of convection is obtained at the third order of the system. The study considers three different forms of temperature modulations. OPM-out of phase modulation, LBMO-lower boundary modulation, IPM-in phase modulation. The finite-amplitude is a function of amplitude ,Tδ frequency ω and the phase differenceθ . The effects of Tδ and ω on heat/mass transports have been analyzed and depicted graphically. The study shows that heat/mass transports can be controlled effectively by thermal modulation. Further, it is found that the internal Rayleigh number iR enhances heat transfer and reduces the mass transfer in the system.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2021, 26, 1; 135-155
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Engineering the optical and mechanical properties exhibited by a titanium dioxide thin film with gold nanoparticles
    Autorzy:
    Morales-Bonilla, S
    Torres-Torres, C
    Trejo-Valdez, M
    Torres-Torres, D
    Urriolagoitia-Sosa, G
    Hernandez-Gomez, L H
    Urriolagoitia-Calderon, G
    Powiązania:
    https://bibliotekanauki.pl/articles/174855.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    optical Kerr effect
    nonlinear optics
    nanomaterials
    Opis:
    Thermo-optic and electrostrictive contributions to the nonlinear refractive index were observed in a titanium dioxide thin film with embedded gold nanoparticles. A sol–gel method was employed for preparing thin solid film samples. The nanosecond nonlinear optical properties and the Young’s modulus parameter were changed by shifting the optical absorption band associated with the localized surface plasmon of resonance of the gold nanoparticles with platinum. The third order nonlinear optical phenomena exhibited by the sample were induced by the second harmonic of a Nd-YAG laser with 532 nm wavelength; the nonlinear optical measurements were obtained by monitoring the transmittance and the amplitude modification for the vectorial components of the electric fields in a two-wave interaction. Optical evaluations were confirmed considering a straightforward measurement of the change in the refractive index of the sample when the sample was located in a Michelson interferometer.
    Źródło:
    Optica Applicata; 2013, 43, 4; 651-661
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zastosowanie zredukowanej metody Prony’ego do pomiaru mocy czynnej odbiorników nieliniowych
    Application of the reduced Pronys method to active power measurements of nonlinear loads
    Autorzy:
    Papierz, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/154634.pdf
    Data publikacji:
    2013
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    zredukowana metoda Prony'ego
    moc czynna
    wyższe harmoniczne
    przeciek widma
    reduced Prony's method
    active power
    harmonics
    spectrum leakage effect
    Opis:
    W artykule dokonano omówienia teoretycznych podstaw zredukowanej metody Prony’ego oraz analizy jej zastosowania do pomiarów mocy czynnej odbiorników nieliniowych – przykład stanowił model świetlówki kompaktowej. Przeprowadzono badania porównawcze przekształcenia Fouriera oraz zredukowanej metody Prony'ego. Na podstawie przeprowadzonych badań symulacyjnych przedstawione zostały zalety omawianej metody - w szczególności brak wpływu zjawiska przecieku widma na otrzymywane wyniki.
    The paper contains discussion on the reduced Prony's method. This method was invented by a French mathematic, Gaspard Riche de Prony. Now it is widely used i.e. in digital signal processing. The Prony’s method is based on the representation of a signal as a linear combination of exponential functions. In a reduced variant of the method, the frequency component vector is assumed to be known, which allows calculating the amplitude and phase of each harmonic [5]. A few simulations in Matlab-Simulink showing comparison between the Prony's method and the Fourier transformation were performed. At first the known test signal consisting of odd harmonics form the first to the seventh (Section 3) was used. Next, the simulation model of a compact fluorescent lamp was used as an example of a nonlinear load (Section 4). In this case, the active power of harmonics was measured. The simulations clearly show that in the case of spectral leakage the reduced Prony's method is much more better than the Fourier transformation – the errors of active power measurements are very small (Table 4).
    Źródło:
    Pomiary Automatyka Kontrola; 2013, R. 59, nr 7, 7; 605-608
    0032-4140
    Pojawia się w:
    Pomiary Automatyka Kontrola
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of ideal and non-ideal excitation sources on the dynamics of a nonlinear vibro-impact system
    Autorzy:
    Moraes, F. H.
    Pontes, B. R. (jr)
    Silveira, M.
    Balthazar, J. M.
    Brasil, R. M. L. R. F.
    Powiązania:
    https://bibliotekanauki.pl/articles/281540.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    vibro-impact system
    limited power supply
    non-ideal excitation
    Sommerfeld effect
    Opis:
    The objective of the present work is to analyze the dynamics of a vibro-impact system consisting of two blocks of different mass coupled by a spring with two stages. Two different types of excitation sources for the system are used in the analysis: the first is an ideal excitation in form of a harmonic force, and the second is a non-ideal excitation in form of a DC electric motor with limited power supply which has an unbalanced rotor. The control parameter for both situations is the excitation frequency of the system. The analysis includes time histories of displacements and velocities, phase portraits and diagrams of the displacement and frequency, used to show the Sommerfeld effect. For certain values of the parameters of the system, the motion is chaotic. The mathematical model of the system is used to obtain an insight to the global dynamics of the vibro-impact system. The model with a non-ideal excitation is more realistic, complete and complex than the model with the ideal excitation.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2013, 51, 3; 763-774
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The effect of modulation on heat transport by a weakly nonlinear thermal instability in the presence of applied magnetic field and internal heating
    Autorzy:
    Manjula, S. H.
    Kiran, Palle
    Narsimlu, G.
    Roslan, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1839705.pdf
    Data publikacji:
    2020
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    modulacja
    pole magnetyczne
    ogrzewanie
    Ginzburg-Landau equation
    temperature modulation
    applied magnetic field
    internal heating
    Opis:
    The present paper deals with a weakly nonlinear stability problem under an imposed time-periodic thermal modulation. The temperature has two parts: a constant part and an externally imposed time-dependent part. We focus on stationary convection using the slow time scale and quantify convective amplitude through the real Ginzburg-Landau equation (GLE). We have used the classical fourth order Runge-Kutta method to solve the real Ginzburg-Landau equation. The effect of various parameters on heat transport is discussed through GLE. It is found that heat transport analysis is controlled by suitably adjusting the frequency and amplitude of modulation. The applied magnetic field (effect of Ha) is to diminish the heat transfer in the system. Three different types of modulations thermal, gravity, and magnetic field have been compared. It is concluded that thermal modulation is more effective than gravity and magnetic modulation. The magnetic modulation stabilizes more and gravity modulation stabilizes partially than thermal modulation.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2020, 25, 4; 96-115
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Stability analysis and internal heating effect on oscillatory convection in a viscoelastic fluid saturated porous medium under gravity modulation
    Autorzy:
    Bhadauria, B. S.
    Singh, M. K.
    Singh, A.
    Singh, B. K.
    Kiran, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/265014.pdf
    Data publikacji:
    2016
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    analiza stabilności
    grawitacja
    ciecz lepkosprężysta
    nonlinear stability analysis
    complex Ginzburg-Landau equation
    gravity modulation
    internal heating
    bifurcation
    Opis:
    In this paper, we investigate the combined effect of internal heating and time periodic gravity modulation in a viscoelastic fluid saturated porous medium by reducing the problem into a complex non-autonomous Ginzgburg-Landau equation. Weak nonlinear stability analysis has been performed by using power series expansion in terms of the amplitude of gravity modulation, which is assumed to be small. The Nusselt number is obtained in terms of the amplitude for oscillatory mode of convection. The influence of viscoelastic parameters on heat transfer has been discussed. Gravity modulation is found to have a destabilizing effect at low frequencies and a stabilizing effect at high frequencies. Finally, it is found that overstability advances the onset of convection, more with internal heating. The conditions for which the complex Ginzgburg-Landau equation undergoes Hopf bifurcation and the amplitude equation undergoes supercritical pitchfork bifurcation are studied.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2016, 21, 4; 785-803
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The effect of the type of elements used to stiffen thin-walled skins of load-bearing aircraft structures on their operating properties. Experimental tests and numerical analysis
    Wpływ rodzajów usztywnień pokryć cienkościennych struktur nośnych statków powietrznych na ich właściwości eksploatacyjne. Badania eksperymentalne i analiza numeryczna
    Autorzy:
    Kopecki, T.
    Mazurek, P.
    Lis, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/1365790.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    thin-walled structures
    loss of stability
    aircraft load-bearing structures
    finite elements method
    nonlinear numerical analyses
    operating stability
    ustroje cienkościenne
    utrata stateczności
    lotnicze struktury nośne
    metoda elementów skończonych
    nieliniowe analizy numeryczne
    trwałość eksploatacyjna
    Opis:
    The paper presents results of a study on thin-walled structures modelling representative fragments of aircraft fuselages subjected to bending and torsion. The type of the considered load and deformation corresponds to the state of such structures under in-flight conditions. The subject of the study were structures made of composite materials. Adopted assumptions include admissibility of post-buckling deformation in the operating load regime. Results of experimental studies are presented together with nonlinear numerical analyses carried out with the use of the finite elements method applied to a number of variant structures provided with various types of skin stiffening elements. Operating properties of the examined structures have been compared on the grounds of adopted criteria.
    Praca prezentuje wyniki badań ustrojów cienkościennych, stanowiących modele reprezentatywnych fragmentów struktur lotniczych, poddawanych zginaniu oraz skręcaniu. Rodzaj obciążenia oraz deformacji odpowiada stanowi struktury w warunkach eksploatacji. Przedmiotem rozważań były ustroje wykonane z kompozytów. Przyjęto założenie o dopuszczalności deformacji zakrytycznych dla obciążeń eksploatacyjnych. Przedstawiono wyniki badań eksperymentalnych i nieliniowych analiz numerycznych w ujęciu metody elementów skończonych szeregu wariantów ustrojów, zawierających różne rodzaje usztywnień pokryć. Dokonano porównania właściwości eksploatacyjnych badanych ustrojów, w oparciu o przyjęte kryteria.
    Źródło:
    Eksploatacja i Niezawodność; 2016, 18, 2; 164-170
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-39 z 39

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