Noise diagnostics of advanced composite materials for structural applications
Our study is focused on noise diagnostics of an advanced composite material for structural applications called extren, which consists of a combination of a fibre glass reinforcement and a resin binder. Electromagnetic and acoustic emission signals appear during mechanical loading of the material under investigation. They carry information about micro-cracks generated in tested materials. We made long-time simultaneous multi-channel measurements of both signals for various loading conditions, carried out time development of noise spectrum, evaluated parameters of EME and AE events, studied their time development, correlations between them and made statistical analyses of signals and their parameters.
Statistical characteristics of electromagnetic emission signals of mechanical loaded composite samples
1 Department of Physics, Faculty of Electrical Engineering and Communication, BUT, Technická 10, 616 00 Brno E-mail: xpodsh00@stud.feec.vutbr.cz Abstract: This article presents study of statistical characteristics of EME signals. The theoretical part contains a description of stochastic nature of electromagnetic emission. We describe the measuring system, the sequence of the experiment, statistical characteristics (probability density function, mean quantity and dispersion) and spectral analysis (voltage and current power spectral density of measured EME signals). In the practical part of the article we also have compared results obtained on the basis of experiment with theory.
Political authority and obligation in Aristotle
1. The explanatory power of ethics in Aristotle's theory of politics and law 2. Nature and normativity 3. The concept of political authority 4. Morality and political obligation 5. The question of political obligation 6. The justification of political authority 7. The limits of political obligation Conclusion Index locorum Index nominum General index