Comparing the stretching technique and the wavelet cross-spectrum technique for measuring stress-induced wave-velocity changes in concrete

Coda wave interferometry (CWI) holds promise as a technique for concrete stress monitoring. This is because the coda, which consists of multiply scattered arrivals, is the result of propagation through the medium over large distances. As such, it is sensitive to both minute structural changes and small velocity changes in that medium....

A Self Bias-flip Piezoelectric Energy Harvester Array without External Energy Reservoirs achieving 488% Improvement with 4-Ratio Switched-PEH DC-DC Converter

With the advent of the lnternet-of-Things (1oT) era, sensor nodes are required in almost all fields to achieve a better interaction between humans and the environment. Piezoelectric energy harvester (PEH), which exhibits an equivalent electrical model of an AC current source /P in parallel with the inherent capacitor CP, is a promising...

Acoustic Emission-Based Detection in Restricted-Access Areas Using Multiple PZT Disc Sensors

The performance of the Acoustic Emission (AE) technique is significantly dependent on the sensors attached to the structural surface. Although conventional commercially AE sensors, like R15a and WSa sensors, have been extensively employed in monitoring many different structures, they are unavailable in restricted-assess areas. In contrast,...