Temat: 02.60.Lj - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: B-Spline Solution for a Convection-Diffusion Equation
Autorzy:: Caglar, H.
Caglar, N.
Ozer, M.
Tematy:: 02.60.-x
02.60.Lj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1194831.pdf Link otwiera się w nowym oknie
Opis:: This paper is concerned with the numerical solution of the convection diffusion problems. A family of B-spline methods has been considered for the numerical solution of the problems. The results showed that the present method is an applicable technique and approximates the exact solution.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: The Numerical Solution of Fractional Diffusion Equation by Using Local Polynomial Regression
Autorzy:: Caglar, H.
Caglar, N.
Ozer, M.
Tematy:: 02.60.-x
02.60.Lj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1194848.pdf Link otwiera się w nowym oknie
Opis:: In this paper, we apply the local polynomial regression for the solution of the one-dimensional fractional diffusion equation. The Caputo fractional derivative is used for the formulation. A numerical example is given to show the application of the present method. The effect of the fractional order (α) of the equation is illustrated by changing α from 1.01 to 1.99.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Numerical Simulation of Acoustic Wave Propagating in a Spherical Object Filled with Insulating Oil
Autorzy:: Wotzka, D.
Zmarzły, D.
Boczar, T.
Tematy:: 02.60.Lj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1506871.pdf Link otwiera się w nowym oknie
Opis:: Results of a numerical simulation of an acoustic wave that propagates in a spherical object filled with insulating oil are presented in the paper. The sinusoidal acoustic wave is generated by an electro-acoustic transducer mounted in the middle of the object. Presented results depict acoustic pressure distribution within the transient and the steady states in a two-dimensional object. Furthermore, comparison of short time simulations adapting different mesh element size is presented.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Simplified Solving Procedure for the One-Dimensional Schrodinger Equation with Asymmetrical Boundary Conditions
Autorzy:: Puszkarski, H.
Tematy:: 03.65.Ge
02.60.Lj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2011047.pdf Link otwiera się w nowym oknie
Opis:: We propose a new simplified procedure for finding the analytical solutions of the stationary one-dimensional Schrodinger equation, with asymmetric boundary conditions imposed on the equation. The essence of the method consists in expressing the general solution explicitly in terms of the boundary parameters in a form which, by itself, satisfies one of the boundary conditions involved; then, the other boundary condition gives straightforwardly the characteristic equation. This method may turn out to be beneficial with regard to the recently growing interest in one-dimensional quantum systems.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Treatment of the Periodically Inhomogeneous Surface: Multiple Boundary Condition
Autorzy:: Puszkarski, H.
Krawczyk, M.
Tematy:: 68.35.-p
02.60.Lj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2014016.pdf Link otwiera się w nowym oknie
Opis:: We deal with the following question: how can the composite nature of a boundary condition formulated for a periodically inhomogeneous surface and involving the composite surface parameter, be treated analytically? We show that when the appropriate Fourier transformation is applied, the composite boundary condition reduces to a specific eigenproblem condition, which constitutes the spectrum of eigenvalues of an "effective" surface parameter, a novel quantity we introduced to account for the nonhomogeneity of the surface.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: The Analysis of Wind Turbine Construction Safety System that Uses Vibroacoustic Diagnostics
Autorzy:: Szmechta, M.
Tematy:: 02.60.Lj
43.40.Le; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1399405.pdf Link otwiera się w nowym oknie
Opis:: The paper presents an analysis of the results of monitored on-line Enercon E40/6.44 wind turbine with gearless designed synchronous generator and a nominal power of 600 kW. In recent months, this plant underwent with high frequency emergency stopped, the source of which was the acceleration control system located in the nacelle. This situation causes significant and unnecessary overload of the power plant components but most of all causes significant losses of production of renewable energy due to operational downtime. This article analyzes the circumstances of errors reported by the turbine control system associated with the acceleration sensor based on data recorded during several months of using on-line SCADA system. An assessment of the impact of a number of indicators related to the wind speed and direction of the nacelle on the operation of the safety system of the turbine has been carried out. Also the possible causes of irregularities were proposed, which may be the subject of further research, especially with the use of advanced diagnostics based on vibroacoustic method.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Frequency and Time-Frequency Analysis of Acoustic Cavitation Noise in Insulating Oils
Autorzy:: Szmechta, M.
Boczar, T.
Frącz, P.
Tematy:: 02.60.Lj
43.40.Le; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1493273.pdf Link otwiera się w nowym oknie
Opis:: The paper presents some observations of ultrasound induced cavitation phenomenon in a mineral insulating oil. The acoustic cavitation phenomenon was generated at different signal frequencies and rms voltage value supplied to round piezoelectric transducers. Used transducers have created a high energy acoustic field in prepared insulating oil samples. The acoustic emission signal contains a broad-band noise and a fundamental frequency component and its harmonics, produced by the direct driving acoustic field. The paper presents the spectral analysis of acoustic emission signal observed during acoustic cavitation in insulating oils. To emphasize the changes in acoustic cavitation intensity also time-frequency analysis was used and some spectrograms were evaluated. The measurement uncertainty of some frequency-rms voltage pairs was very unfavorable. The main application expected with created cavitation measurement system is to develop a diagnostic tool for the aging of oil, based on the hypothesis that the measured cavitation intensity and spectrum could be affected by aging. Previous published measurements showed some relationship between insulating oil aging process and changes of acoustic emission of cavitations.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Mathematical Model and Numerical Analysis of~AE Wave Generated by Partial Discharges
Autorzy:: Wotzka, D.
Boczar, T.
Fracz, P.
Tematy:: 43.40.Le
02.60.Lj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1493290.pdf Link otwiera się w nowym oknie
Opis:: Paper presents definition of a mathematical model describing acoustic emission signals generated by partial discharges occurring in oil immersed electric power transformers. Time runs, power spectral density graphs and spectrograms of acoustic emission signals generated in experiments, performed under laboratory conditions, and of equivalent signals, calculated on the basis of the mathematical model, are presented. Furthermore, results of numerical simulations of acoustic pressure distribution inside a tank filled with insulation oil are presented in the paper. In the center of the tank acoustic emission wave sources were placed, each generating signals described by the model developed.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 9.

Tytuł:: Galerkin Versions of Nonsingular Trefftz Method Derived from Variational Formulations for 2D Laplace Problem
Autorzy:: Brański, Adam
Borkowska, Dorota
Tematy:: 02.60.Lj
02.30.Jr
41.20.Cv; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1402182.pdf Link otwiera się w nowym oknie
Opis:: In the paper, application of the Trefftz complete functions and Kupradze functions in two variational formulations is compared. They are applied in the original formulation and in the inverse one to the solution of boundary value problems of two-dimensional Laplace's equation. In these formulations, both solution and weighting functions are assumed to be of the same type, either the Trefftz function or the Kupradze function. Thus Galerkin versions of the methods are considered. All methods lead to the BEM and they are nonsingular. The relationship between the groups of methods of the original and inverse formulations is noticed. Numerical experiments are conducted for the Motz's problem. The accuracy and simplicity of the methods are discussed. All methods give comparable results. Since they are nonsingular, they may be successfully applied to solving boundary problems.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: B-Spline Solution and the Chaotic Dynamics of Troeschs Problem
Autorzy:: Caglar, H.
Caglar, N.
Ozer, M.
Tematy:: 05.45.Pq
02.60.-x
02.60.Lj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1291812.pdf Link otwiera się w nowym oknie
Opis:: A B-spline method is presented for solving the Troesch problem. The numerical approximations to the solution are calculated and then their behavior is studied and commenced. The chaotic dynamics exhibited by the solutions of Troesch's problem as they were derived by the decomposition method approximation are examined and an approximate critical value for the parameter λ is introduced also in this study. For the parameter value slightly less than λ ≈ 2.2, the solutions begin to show successive bifurcations, finally entering chaotic regimes at higher λ values. The effectiveness and accuracy of the B-spline method is verified for different values of the parameter, below its critical value, where the first bifurcation occurs.
Dostawca treści:: Biblioteka Nauki

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