Pattern recognition of acoustic emission signal during the mode I fracture mechanisms in carbon- epoxy composite

The aim of the paper is to use Acoustic Emission technique to distinguish the micro/macro failure mechanisms of carbon-epoxy composite laminates during Double Cantilever Beam (DCB) tests. In order to recognize and detect different damage mechanisms, Self-Organizing Map (SOM) method has been used to cluster the AE signals according with the fracture mode that originated them. In addition, most significate Learning vector quantization (LVQ) program has been applied to verify the signals. Five AE features were selected as main parameters: Rise-time, Counts, Energy, Duration and Amplitude. The results highlighted that different signals can be recognized and classified related to their origin. The failure mechanisms detected are Matrix cracking, delamination, and fiber breakage. Scanning Electron Microscopy (SEM) images validate the results. Mathematics data and experimental results confirmed a good converging of AE dat

The relation between environmental parameters of Hormuzgan coastline in Persian Gulf and occurrence of the first harmful algal bloom of Cochlodinium polykrikoides (Gymnodiniaceae)

Cochlodinium polykrikoides was bloomed in the Persian Gulf for the first time in September 2008, started from the Strait of Hormuz and then spread out towards the northern parts covering most of the areas of the Gulf and lasted 8 months. In order to find out environmental conditions during the bloom, a monthly sampling program was carried out in seven surface stations in 2008-2009. At each station, three samples (triplicates) were collected for phytoplankton analysis and also one sample for environmental analyses, including salinity, chlorophyll a and nutrients. Blooms of C. polykrikoides were observed with a seawater temperature of 20.1 to 31.0 °C, salinity 37.0-40.1 ppt and nutrient concentration ranges during the bloom and red tide were 0.064-0.707 mg/l nitrate + nitrite and 0.001-1.66 mg/l phosphate, respectively. Maximum of C. polykrikoides abundance was measured 26 × 106 cells L-1 in October 2008. Kruscal wallis test demonstrated a significant difference in densities and chlorophyll-a in different months and seasons not in different stations. This study showed increase of temperature (>31.0 °C) stopped bloom and red tide due to C. polykrikoides in both the eastern and middle sampling stations but in the western stations was determined decrease in nutrient amounts as the major factor therefore increased nutrient of coastal waters, and environmental conditions could have efficacy the occurrence of this dinoflagellate

Metastases free thyroid cancer patients harbouring TERT mutations may benefit from a more intensive treatment and follow-up

[No abstract available

Supervised and non-supervised AE data classification of nanomodified CFRP during DCB tests

Aim of the paper is to use acoustic emissions to study the effect of electrospun nylon 6,6 Nanofibrous mat on carbon-epoxy composites during Double Cantilever beam (DCB) tests. In order to recognize the effect of the nanofibres and to detect different damage mechanisms, k-means clustering of acoustic emission signals applied to rise time, count, energy, duration and amplitude of the events is used. Supervised neural network (NN) is then applied to verify clustered signals. Results showed that clustered acoustic emission signals are a reliable tool to detect different damage mechanisms; neural network showed the method has a 99% of accuracy