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Pure and composite nickel deposits containing nano-TiO 2 particles (d m = 21 nm) were produced under direct-DC and pulse current-PC conditions. The influence of pulse frequency on the codeposition of TiO 2 particles, preferred orientation of Ni crystallites and grain size, as well as microhardness of the composites, was investigated systematically. Composites prepared in PC regime displayed higher incorporation percentage than those obtained under DC conditions, and the highest incorporation rates were achieved at pulse frequencies m [ 100 Hz. The application of pulse frequency accompanied by the embedding of TiO 2 nanoparticles in the nickel matrix resulted in a strong influence upon the crystalline orientation, the grain size and the corresponding microhardness. All composites exhibited higher microhardness values compared to the pure deposits, independent of the applied current conditions. Overall, when ascribing the observed strengthening effect of composites, not only grain refinement and dispersion strengthening mechanisms but also preferred crystalline orientation should be taken into consideration.

Direct current electrodeposited Sn–Ni/TiO2 nanostructured coatings were produced by embedding two different doped types of TiO2 particles within the alloy matrix, a commercially available doped carbon-based and doped N,S-TiO2 particles. The structural characteristics of the composite coatings have been correlated with the effect of loading, type of particles in the electrolytic bath, and the applied current density. Regardless of the type of doped particles TiO2, increasing values of applied current density resulted in a reduction of the co-deposition percentage of TiO2 particles and an increase of Tin content into the alloy matrix. The application of low current density values accompanied by a high load of particles in the bath led to the highest codeposition percentage (~3.25 wt.%) achieved in the case of embedding N,S-TiO2 particles. X-ray diffraction data demonstrated that in composite coatings the incorporation of the different types of TiO2 particles in the alloy metal matrix modified significantly the nano-crystalline structure in comparison with the pure coatings. The best photocatalytic behavior under visible irradiation was revealed for the composite coatings with the highest co-deposition percentage of doped N,S-TiO2 particles, that also exhibited enhanced wear resistance and slightly reduced microhardness compared to pure ones.

This study focused on the development of reading and writing skills to a group of B1 level learners of English in a private language institute in Athens, Greece with the aid of blogs (a web tool), since Computer Assisted Language Learning (CALL) enhances foreign language learning. To this end, two groups of young learners were formed; the control group which was taught through the traditional coursebook and the experimental group which was taught through a differentiated approach to language teaching. The differentiated approach which was applied involved eight teaching sessions in a private language institute. Pre-tests and post-tests were administered to both groups in order to evaluate the use of CALL in the improvement of literacy skills. Pre- and post- semi-structured interviews were also conducted with the students of the experimental group to evaluate their attitudes and feelings before and after the instruction. The aim of using blogs, as a web tool, was to enhance collaborative learning and social interaction. This research attempted to prove that blogs create a social interaction between students, and between the students and the teacher. For the purposes of this research, students were involved in process writing by making drafts and writing their posts and in active reading when they read other posts and texts from other web sites.