Coupling an annotated corpus and a lexicon for state-of-the-art POS tagging

This paper investigates how to best couple hand-annotated data with information extracted from an external lexical resource to improve part-of-speech tagging performance. Focusing mostly on French tagging, we introduce a maximum entropy Markov model-based tagging system that is enriched with information extracted from a morphological resource. This system gives a 97.75?% accuracy on the French Treebank, an error reduction of 25?% (38?% on unknown words) over the same tagger without lexical information. We perform a series of experiments that help understanding how this lexical information helps improving tagging accuracy. We also conduct experiments on datasets and lexicons of varying sizes in order to assess the best trade-off between annotating data versus developing a lexicon. We find that the use of a lexicon improves the quality of the tagger at any stage of development of either resource, and that for fixed performance levels the availability of the full lexicon consistently reduces the need for supervised data by at least one half.     

Energy savings potential by integrating Phase Change Material into hollow bricks: The case of Moroccan buildings

The building sector in Morocco represents 25% of the country’s total energy consumption. The poor thermal performance of the building envelopes is one of the principal reasons for this consumption rate. In this study, the efficiency of integrating Phase Change Materials (PCM) into hollow bricks used in three typical housing types in the six climate zones in Morocco is investigated. The numerical model is based on the heat transfer equation and the apparent heat capacity formulation to model the phase change. A heat flux analysis is performed at the internal surface of the wall, giving a good understanding of the thermal behavior of hollow bricks with PCMs compared with hollow bricks with air. The results show that the heat flux density at the internal face of the wall is constant when the PCM is partially solid/liquid, and follows the outdoor conditions when the PCM is fully solid or fully liquid. Irrespective of the climate zone, the PCM with a 32 °C median melting temperature reduces the heat flux peak value in the hotel housing while the PCM with a 37 °C median melting temperature is better for the individual and collective housing. On the other hand, the PCM with a 27 °C median melting temperature is able to save up to 25% and 40% of energy consumption in the Saharan climate and oceanic climate, respectively.     

Novel semi-interpenetrated networks based on collagen-polyurethane-polysaccharides in hydrogel state for biomedical applications

The development of collagen hydrogels with tailored properties for improved applications in biomedicine represents an area of opportunity for materials science. The collagen can form semi-interpenetrated networks (semi-IPN) with various natural and/or synthetic polymers. This work aims the preparation of novel hydrogels generated from a collagen matrix cross-linked with polyurethane (PU), and the subsequent inclusion of polysaccharide chains to form semi-IPN systems with improved properties. The choice of polysaccharides for this purpose is related to their ability to modulate the biocompatibility and the antibacterial capacity in various biomedical strategies. The work contemplates to study the effect of the chemical structure of polysaccharide (hydroxyethylcellulose (HEC), hydroxypropylmethylcellulose (HPMC) or starch (Alm)) on the properties of these novel hydrogels. The results indicate that the semi-IPN hydrogels that include Alm exhibit the formation of stronger intermolecular interactions promoted by hydrogen bonds than HEC and HPMC, significantly improving the mechanical properties and their degradation rate in acidic, alkaline, and proteolytic media; also showing high capacity to inhibit the growth of E. colli. The semi-IPN hydrogels based on HEC and HPMC exhibit excellent improvement in both thermal and proteolytic degradation, compared with the collagen-PU matrix. On the other hand, this semi-IPN system does not present cytotoxic character for monocytes and fibroblasts growing for up to 48 h of culture. Therefore, these innovative 3D matrices will be excellent candidates with potential application in biomedical strategies such as wound healing dressings.     

An original experimental approach showing that most nonlinearities expressed by filled elastomers relate to microscopic friction and cavitation

Filled elastomers present a highly nonlinear behavior when submitted to cyclic mechanical loads. Origins of these nonlinearities are still uncertain, but many models rely on micromechanisms such as friction or cavitation at the filler/binder interface. To substantiate these hypotheses, an experimental approach is proposed to assess the real effects of friction and cavitation on the macroscopic response of filled elastomers. A linear, viscoelastic, transparent material is used to create macroscopic samples in which mechanisms are activated, separately or jointly. The response of these samples to cyclic mechanical loads shows that each mechanism generates some typical nonlinearities. A deeper analysis of the resulting curves allows a correlation between the nonlinearities characteristics (shapes and amplitudes) and the ones expressed by filled elastomers, providing clues for the development of future models.     

Compatibilization efficiency in post‐consumer recycled polyethylene/polypropylene blends: Effect of contamination

This work investigates the effect of ethylene–octene copolymer (EOC) as a compatibilizer for two virgin and two recycled polyethylene/polypropylene blends. In particular, a focus is made on the interfering effects of contamination in recycled materials. Scanning electron microscopy (SEM) shows that (i) recycled compounds have smaller domain sizes than virgin compounds, and (ii) addition of a compatibilizer is much more effective on domain sizes reduction in virgin compounds than in recycled ones. Conversely, transmission electron microscopy, coupled with energy dispersive X‐ray spectroscopy, shows the presence of nano‐size contaminants in both recycled blends. Such contaminants are considered responsible for the above mentioned observations in SEM. Mechanical characterizations are also in good agreement with morphological observations. Although recycled compounds containing EOC show improved deformability, the ultimate deformation of virgin compounds is much higher. POLYM. ENG. SCI., 55:2368–2376, 2015. © 2015 Society of Plastics Engineers     

Zirconium Carbide Oxidation: Maltese Cross Formation and Interface Characterization

Oxidation of Metals - Oxidation of dense hot-pressed ZrC specimens from 1073 to 1473 K was investigated using an in situ technique: HT-ESEM. Cuboid specimens were monitored on the surface...