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P. Zięba

Abstract

The discontinuous precipitation (DP) belongs to a group of diffusive solid state phase transformations during which the formation of a new phase is heterogeneous and limited to a migrating reaction front (RF). The use of analytical electron microscopy provided reliable information that there is no differences in the diffusion rate at the stationary grain boundary and moving RF of DP reaction. On the other hand, the use of “in situ” transmission electron microscopy observations indicated the importance of stop-go motion or oscillatory movement of the RF.

During 2004-2016 period more or less 280 papers were published in which the terms “discontinuous precipitation, “cellular precipitation”, discontinuous coarsening” appeared either in the abstract or in key-words.

In the present contribution, the research on the DP reaction will be reviewed taking into account new aspects of theories and modelling, new evidences and findings, effect of various factors including third element, external stresses, plastic deformation and GB orientation, occurrence in less known systems and alloys like: superalloys, nitrided Fe-based alloys and Cu-based alloys. Finally, some suggestions for the future research will be formulated.

Open access

G. Kulesza, P. Panek and P. Zieba

The paper presents the results of the texturization process of the multicrystalline silicon wafers carried out in ternary HF/HNO3/diluent solution, where the diluent was either CH3COOH or H2O, at varying HF/HNO3 volume ratio and different time of texturization process. The technique of scanning electron microscopy was used to characterize the morphology of the obtained multicrystalline silicon surfaces, with subsequent surface reflectivity measurements. The appropriate selection of mixture components lead to a significant reduction in the reflectivity of the incident solar radiation in the relatively short time of 60 seconds. The resultant electric parameters were nearly the same as those for the commercial samples but obtained after 3 minutes.

Open access

P. Nosal, M. Murawski, P. M. Bartlewski, J. Kowal, M. Skalska and D. A Zięba

Summary

One of the alternative methods of parasite control, of particular importance in sustainable farming, is the use of medicinal plants. The specific aim of the present field trial was to assess the anti-parasitic effects of herbal extracts contained in a commercially available lick formulation for sheep. At the outset of this study conducted during the grazing season, all animals were de-wormed and then randomly assigned to one of the two separately kept groups (treatment and control), each consisting of 25 animals (11 ewes and 14 lambs). The treatment group received mineral licks containing the extracts of the plants with anti-parasitic properties, while control animals received standard mineral licks ad libitum. Rectal fecal samples were collected monthly from all animals for the McMaster analyses. There were no significant differences in the prevalence and intensity of helminth infections between the treatment and control groups. Thus, we were not able to ascertain the efficacy of the commercial herbal de-wormer tested for the control of gastrointestinal helminths in grazing ewes and their lambs.