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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

A Fourier integral computer for calculation of antenna radiation patterns

Hollis, John Searcy 05 1900 (has links)
No description available.
42

Three-dimensional solution of electrostatic fields within a particular system of annular cylinders

Wagenaar, Loren B. January 1973 (has links)
A mathematical method is developed for the analysis of the electrostatic fields existing within finite, three-dimensional, cylindrically shaped regions which do not contain the axis of revolution. The derived method defines the potential field within such a region provided that the potentials are known at the boundaries, that the insulating media has homogeneous, linear, and isotropic characteristics, and that the region is charge free. The general solution for the potential field involves forms of both the Fourier and the Fourier Bessel series, and the resulting series solution is shown to be uniformly convergent . It is also shoran that this potential field series solution can be integrated and differentiated to yield series solutions for electric fiend and capacitance and that these solutions are also uniformly convergent.
43

Fourier series-based learning control of nonlinear systems with backlash /

Jiang, Junmin. January 2008 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references (leaves 75-79). Also available in electronic version.
44

Use of Fourier series in examining the distortional buckling of beams /

Ng, Maurice Loong-Hon. January 2003 (has links) (PDF)
Thesis (MPhil.) - University of Queensland, 2003. / Includes bibliography.
45

Improvement of the Fourier series based learning control scheme in a low-bandwidth system application /

Zhu, Yang. January 2005 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 74-77). Also available in electronic version.
46

Comparison between the performances of a linear isolator and an isolator with a geometrically nonlinear damper

Carranza López, José Camilo [UNESP] 21 October 2013 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:27:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-10-21Bitstream added on 2014-06-13T20:35:23Z : No. of bitstreams: 1 000740391.pdf: 3050391 bytes, checksum: a8c46856114d4e5e5f67e81c1feb384d (MD5) / Nesta dissertação investiga-se o comportamento de um sistema de isolamento de vibrações de um grau de liberdade com amortecimento não linear. As transmissibilidades das forças e de movimento deste sistema são comparadas com as de um sistema de isolamento de vibrações linear. O sistema não linear é composto por uma mola e um amortecedor viscoso, ambos lineares, que estão acoplados a uma massa de modo tal que o amortecedor é perpendicular à mola. O sistema é excitado harmonicamente por um deslocamento da base ou por uma força na direção da mola. Quando o sistema é excitado por uma forca harmônica, as forças transmitidas através da mola e do amortecedor são analisadas separadamente, decompondo-as em termos dos seus harmônicos; permitindo assim determinar a contribuição individual de cada elemento no comportamento não linear do sistema como um todo. A transmissibilidade do sistema de isolamento não linear é calculada por meio de expressões analíticas validas para excitações com pequenas amplitudes, já para excitações com amplitudes grandes, calcula-se por meio de simulações numéricas. / In this work the behaviour of a single degree of freedom (SDOF) passive vibration isolation system with a geometrically nonlinear damper is investigated, and its displacement and force transmissibilities are compared with that of a linear system. The nonlinear system is composed of a linear spring and a linear viscous damper which are connected to a mass so that the damper is perpendicular to the spring. The system is excited with either a harmonic force or an imposed displacement of the base in the direction of the spring. When excited with a harmonic force, the forces transmitted through the spring and the damper are analysed separately by decomposing the forces in terms of their harmonics. This enables the effects of these elements to be studied and to determine how they contribute individually to the nonlinear behaviour of the system as a whole. The transmissibilities of the nonlinear isolation system are calculated using analytical expressions for small amplitudes of excitation and by using numerical simulations for high amplitudes of excitation.
47

Comparison between the performances of a linear isolator and an isolator with a geometrically nonlinear damper /

Carranza López, José Camilo. January 2013 (has links)
Orientador: Michael John Brennan / Banca: Gilberto Pechoto de Melo / Banca: Paulo Jose Paupitz Gonçalves / Resumo: Nesta dissertação investiga-se o comportamento de um sistema de isolamento de vibrações de um grau de liberdade com amortecimento não linear. As transmissibilidades das forças e de movimento deste sistema são comparadas com as de um sistema de isolamento de vibrações linear. O sistema não linear é composto por uma mola e um amortecedor viscoso, ambos lineares, que estão acoplados a uma massa de modo tal que o amortecedor é perpendicular à mola. O sistema é excitado harmonicamente por um deslocamento da base ou por uma força na direção da mola. Quando o sistema é excitado por uma forca harmônica, as forças transmitidas através da mola e do amortecedor são analisadas separadamente, decompondo-as em termos dos seus harmônicos; permitindo assim determinar a contribuição individual de cada elemento no comportamento não linear do sistema como um todo. A transmissibilidade do sistema de isolamento não linear é calculada por meio de expressões analíticas validas para excitações com pequenas amplitudes, já para excitações com amplitudes grandes, calcula-se por meio de simulações numéricas. / Abstract: In this work the behaviour of a single degree of freedom (SDOF) passive vibration isolation system with a geometrically nonlinear damper is investigated, and its displacement and force transmissibilities are compared with that of a linear system. The nonlinear system is composed of a linear spring and a linear viscous damper which are connected to a mass so that the damper is perpendicular to the spring. The system is excited with either a harmonic force or an imposed displacement of the base in the direction of the spring. When excited with a harmonic force, the forces transmitted through the spring and the damper are analysed separately by decomposing the forces in terms of their harmonics. This enables the effects of these elements to be studied and to determine how they contribute individually to the nonlinear behaviour of the system as a whole. The transmissibilities of the nonlinear isolation system are calculated using analytical expressions for small amplitudes of excitation and by using numerical simulations for high amplitudes of excitation. / Mestre
48

Examining the Absolute Rate of Convergence of Summability Assisted Fourier Series

Wright, Brian M. 05 May 2007 (has links)
No description available.
49

Notes on generalized Fourier series with application to gravitational field determination

Blackshear, Walter Thomas January 1967 (has links)
Let{(}φ<sub>n</sub>(x)} be an orthonormal system in the set of Lebesgue square integrable functions L². Let f𝜖L². The generalized Fourier series of f with respect to {(}φ<sub>n</sub>(x)} is the series ∑<sub>n=0</sub><sup>∞</sup> (f, φ<sub>n</sub>) φ<sub>n</sub>(x), where (f, φ<sub>n</sub>) is the inner product of the functions f an φ<sub>n</sub>. The e existence of a complete orthonormal system in L² is proven. Conditions for convergence of the generalized Fourier series are presented. A discussion of orthogonal polynomials with special emphasis on the Jacobi polynomial systems is presented. A least squares, differential correction, discrete observation procedure is employed to solve the potential equation with boundary conditions in tenns of three special Jacobi systems. / M.S.
50

Determination of Mueller matrix elements in the presence of imperfections in optical components

Chakraborty, Shibalik 15 May 2009 (has links)
The Polarizer-Sample-Analyzer (PSA) arrangement with the optical components P and A rotating with a fixed speed ratio (3:1) was originally introduced to determine nine Mueller matrix elements from Fourier analysis of the output signal of a photodetector. The arrangement is modified to the P'PSAA' arrangement where P' and A' represent fixed polarizers that are added at both ends with the speed ratio of the rotating components (P and A) remaining the same as before. After determination of the partial Mueller matrix in the ideal case, azimuthal offsets and imperfection parameters are introduced in the straight-through configuration and the imperfection parameters are determined from the Fourier coefficients. Finally, the sample is reintroduced and the full Mueller matrix elements are calculated to show the deviation from the ideal case and their dependency on the offsets and imperfection parameters.

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