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1	Simultaneous Oscillations at Two Unrelated Frequencies Jones, N.B. 05 1900 (has links) This thesis is principally concerned with the conditions under which a feedback oscillator with a single non-linear element can support two component waves, These component waves are required to have unrelated frequencies. A theory is produced to predict the oscillation frequencies and amplitudes and examine their stability. The conclusions reached in this thesis are then compared with those reached by previous workers in the same field. The concluding parts of the thesis contain an examination of the possible approximations which can be made in order to represent various non-linear elements mathematically and also a demonstration of a system for examining frequency relationships without recourse to direct numerical measurement. / Thesis / Master of Engineering (ME)
2	Non-conforming Finite Element Methods for Eigenvalue Problems Shen, Hung-Jou 02 August 2005 (has links) The thesis explores the new expansions of eigenvalues for -£Gu =£f£lu in S with the Dirichlet boundary condition u=0 on $partial S$ by two conforming elements: the linear element $P_1$ and the bilinear element $Q_1$, and three non-conforming elements: the rotated bilinear element (denoted $Q_1^{rot}$), the extension of $Q_1^{rot}$ (denoted $EQ_1^{rot}$) and Wilson's element. The expansions indicate that $P_1$, $Q_1$ and $Q_1^{rot}$ provide the upper bounds of the eigenvalues, and $EQ_1^{rot}$ and Wilson's elements provide the lower bounds of the eigenvalues. Comparing the five finite elements, the $Q_1^{rot}$ element is more accurate. By the extrapolation, the superconvergence $O(h^4)$ can be obtained where $h$ is the boundary length of uniform squares. Numerical experiment are carried to verify the theoretical analysis made. (°Ñ·Ó¹q¤lÀÉp.4) extension of rotated bilinear element rotated bilinear element Wilson's element bilinear element linear element non- conforming eigenvalue conforming
3	Dvimasės elektromechaninės sistemos tyrimas / The research of two – mass electromechanical system Juraitis, Sigitas 11 June 2004 (has links) In the final dissertation you will find analyzed the two - mass electromechanical system, finite tightness shaft and non-linear mechanical link included. Explored system shaft has finite tightness, non-linear element - backlash between the parts of mechanical link. The researches of two - mass electromechanical system were made using Simulink program pack. In this paper I have made the structural system scheme, transmission functions and simulated process of two - mass dynamical system. Gained motor and outlet shaft angular rotation speed and motor's electromagnetic moment transitive process curves, by all tightness and backlash worth' s. Researched results give new information about the two - mass electromechanical system' s dynamical process. Electronics and Electrical Engineering Dynamical process Motor Dinaminiai procesai Netiesinis elementas Variklis Transient process Non-linear element Pereinamieji procesai Velenas Shaft Two – mass electromechanical system Dvimasė elektromechaninė sistema

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