The setting of Acoustic Emission detecting parameters in running of steel structured
Acoustic Emission technology is still at the starting stage of monitoring in domestic bridge. To resolve the problem that Acoustic Emission detection parameters in scene are determined. Based on lead-breaking tests confirm threshold and time parameter. Studying on the characteristic of signal propagated and the attenuation laws of velocity and amplitude, it gets references for Acoustic emission technique in detection of the bridge.
Study on the AE Characteristics of Cracking Process in Prestressed Concrete Beams
A series of prestressed concrete beams were loaded at three points subjected to bending until failure.The waveform acoustic emission signals were recorded.Crack initiation and propagation due to bending were monitored and compared with observation.Based on the relationship between the cumulative energy of acoustic emission and time,the waveform acoustic emission signals of different destruction states was picked up and spectral analysis was carried out.According to the value of the energy amplitude of waveform acoustic emission and the comparison of the amplitude and frequency of waveform acoustic emission signals in time domain and frequency domain,different damage stages of the prestressed concrete specimens until failure were divided,and the parameter properties of prestressed concrete specimens were picked up.The research shows that waveform acoustic emission signals can be used to find the characteristics of the different damage stages of prestressed concrete beams under loading in real time.
Degradable polymers : principles and applications
1. Why Biodegradable Polymers? G. Scott. 2. An Overview of Biodegradable Polymers and Biodegradation of Polymers S.H. Huang. 3. Degradation and Stabilization of Carbon-Chain Polymers G. Scott. 4. Techniques and Methods of Polymer Degradation S. Karlsson, A.-C. Albertsson. 5. Biodegradation of Aliphatic Polyesters Suming Li, M. Vert. 6. Starch-Polymer Composites C. Bastioli. 7. Polymers from Renewable Sources E. Chiellini, et al. 8. Sustainable Poly(Hydroxyalkanoate) (PHA) Production G. Braunegg. 9. Polyhydroxyalkanoates: Properties and Modification for High Volume Application I. Chodak. 10. Biodegradable Polymers in Medicine E Piskin. 11. Environmentally Biodegradable Water-Soluble Polymers G. Swift. 12. Plastics and the Environment J. Guillet. 13. Degradable Hydrocarbon Polymers in Waste and Litter Control G. Scott, D.M. Wiles. Subject Index.