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.
Noise diagnostics of composite materials by using spectral characteristics of electromagnetic emission
Our study is focused on the use of spectral characteristics of electromagnetic emission signals for damage assessment of mechanical loaded composite materials. We have developed a methodology for evaluation of the power spectral density of the crack electric dipole moment waveform based on the measured voltage at the capacitance sensor measurement circuit output. The obtained characteristics were studied in dependence on the applied force for the various loading conditions.
KANT'S SECOND THOUGHTS ON RACE
During the 1780s, as Kant was developing his universalistic moral theory, he published texts in which he defended the superiority of whites over non-whites. Whether commentators see this as evidence of inconsistent universalism or of consistent inegalitarianism, they generally assume that Kant's position on race remained stable during the 1780s and 1790s. Against this standard view, I argue on the basis of his texts that Kant radically changed his mind. I examine his 1780s race theory and his hierarchical conception of the races, and subsequently address the question of the significance of these views, especially in the light of Kant's own ethical theory. I then show that during the 1790s Kant restricts the role of the concept of race, and drops his hierarchical account of the races in favour of a more genuinely egalitarian and cosmopolitan view.