In this study, two types of specimens, woven [0, 90] s and unidirectional [0] s glass/epoxy composites, were studied. Acoustic emission (AE) monitoring with wavelet-based signal processing technique and Fuzzy C-Means (FCM) clustering method was used to detect the different fracture mechanisms during delamination in quasi-static three-point bending test. The three-point bending test simulates thrust force, the most effective factor in delamination, throughout the process of drilling without backup plate. The obtained AE signals were decomposed into various wavelet levels and classified using FCM. Scanning Electron Microscopy (SEM) observation was used to determine the different fracture mechanisms. The results show that the energy of AE signals has been concentrated in two significant components for both types of specimens, and the dependency percentage of damages in the two specimens is different.

As part of our ongoing studies on the synthesis of bioactive coumarin compounds, we synthesized a series of new coumarin-fused 1,4-thiazepines using a simple method. The biological activity of target compounds along with 3-(2-hydroxybenzylidene)chroman-2,4-dione intermediates was screened by evaluation of their antioxidant and cytotoxic activities. The antioxidant activity was assessed using two methods, namely, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method and ferric reducing antioxidant power (FRAP) assay. 4-Methoxyphenolic compound 5d in thiazepine series showed the most potent scavenging activity, while the 4-bromophenolic derivative 5b was the most efficient compound in FRAP assay. Also, the result of cytotoxic evaluation using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay demonstrated that compound 5b is at least twofold more potent than etoposide against MCF-7, SK-N-MC, and MDA-MB 231 cell lines.

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