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Environmental stress cracking (ESC) is one of the most prominent failure mechanisms for polymer components. The high sensitivity of plastics in regard to environmental influences has always meant that plastics as materials have been viewed very critically in outdoor applications. Recently, the massive occurrence of microplastics in the environment means that questions about the long-term stability of plastic parts and the studies of plastic fragmentation are of great scientific interest. ESC behavior also plays an important role in connection with the formation of microplastics. In this work, the influence of two different sample wetting methods on ESC behavior was investigated. In case A, the sample was in situ wetted with the medium during the measurement by using a sponge. In case B, the sample was wetted by storage in the medium prior to measurement. Different stress cracking agents (SCA) were examined for polymethylmethacrylate (PMMA). Fracture-mechanical fatigue crack propagation (FCP) tests were carried out to quantitatively determine the sensitivity to ESC. Correlations between the absorption behavior and the ESC behavior of the SCA and the resulting morphological phenomena were established. Depending on the wetting method, significant differences in FCP were observed. The in situ wetting of the samples (case A) during the FCP measurement with ethylene glycol (EG) and with deionized water (DI) led to a significant shift in the crack propagation curves to higher ∆K—compared to the PMMA reference. In the case of n-heptane (NH), a more brittle crack propagation behavior was observed due to the chemical interaction with PMMA. The previously immersed samples (case B) give different results. Storage in NH and EG showed no influence on the crack propagation behavior. Samples immersed in DI showed a completely different course of crack growth. At a certain load, a sudden deceleration of the crack propagation and thus a horizontal curve could be seen. Above a certain ∆K value, crack growth began again. Depending on the immersion time (14, 30, or 60 days), this so-called stepped behavior shifted to lower da/dN values.

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We propose a content-based approach to mine parallel resources from the entire web using cross lingual information retrieval (CLIR) with search query relevance score (SQRS). Our method improves mining recall by going beyond URL matching to find parallel documents from non-parallel sites. We introduce SQRS to improve the precision of mining. Our method makes use of search engines to query for target document given each source document and therefore does not require downloading target language documents in batch mode, reducing computational cost on the local machines and bandwidth consumption. We obtained a very high mining precision (88%) on the parallel documents by the pure CLIR approach. After extracting parallel sentences from the mined documents and using them to train an SMT system, we found that the SMT performance, with 29.88 BLEU score, is comparable to that obtained with high quality manually translated parallel sentences with 29.54 BLEU score, illustrating the excellent quality of the mined parallel material.