Damage Detection Based on Electromechanical Impedance Principle and Principal Components

This paper presents a novel time domain approach for Structural Health Monitoring (SHM) systems based on Electromechanical Impedance (EMI) principle and Principal Component Coefficients (PCC), also known as loadings. Differently of typical applications of EMI applied to SHM, which are based on computing the Frequency Response Function (FRF), in this work the procedure is based on the EMI principle but all analysis is conducted directly in time-domain. For this, the PCC are computed from the time response of PZT (Lead Zirconate Titanate) transducers bonded to the monitored structure, which act as actuator and sensor at the same time. The procedure is carried out exciting the PZT transducers using a wide band chirp signal and getting their time responses. The PCC are obtained in both healthy and damaged conditions and used to compute statistics indexes. Tests were carried out on an aircraft aluminum plate and the results have demonstrated the effectiveness of the proposed method making it an excellent approach for SHM applications. Finally, the results using EMI signals in both frequency and time responses are obtained and compared. © The Society for Experimental Mechanics 2014.

The practical interpretation and application of the polluter pays principle

Revisa brevemente la teoría que hay detrás de las dos interpretaciones del principio contaminador-pagador, para comentar las implicaciones de éstas en la política ambiental, y considerar en qué medida este principio es aplicado en la práctica.

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Annotated provisional agenda. Second meeting of the focal points appointed by the Governments of the signatory countries of the Declaration on the application of Principle 10 of the Rio Declaration on Environment and Development in Latin America and the Caribbean

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Provisional agenda. Second meeting of the focal points appointed by the Governments of the signatory countries of the Declaration on the application of Principle 10 of the Rio Declaration on Environment and Development in Latin America and the Caribbean

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Report of the second meeting of the focal points appointed by the governments of the signatory countries of the declaration on the application of principle 10 of the Rio Declaration on Environment and Development in Latin America and the Caribbean, Guadalajara, Mexico, 16 and 17 April 2013

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Access to information, participation and justice in environmental matters in Latin America and the Caribbean: situation, outlook and examples of good practice [Principle 10 of the Rio Declaration on Environment and Development, 1992]

Principle 10 of the Rio Declaration on Environment and Development, 1992