Materials Science Forum Vols. 775-776

Abstract: Hydrophobicity of polymeric insulators of high power transmission line is an important property because it is a good monitor of aging of polymeric outdoor insulator. An employee on the high-voltage transmission line makes this procedure during operation, which can lead to injuries and incorrect estimation of the insulator integrity. In this way, digital image processing is a promising and objective tool to analyze the polymer surface. In this study, two thousand pictures were taken from the wetted insulator surface and analyzed by artificial neural network assisted digital image processing. The neural network used is based on back-propagation method, and Haralicks descriptors were used to quantify the hydrophobic aspect of various polymeric aged surfaces.

Abstract: The disposal of textile waste in water bodies is exacerbating environmental problems, which led scientists to seek natural materials to develop more sustainable ways. Searching for low cost materials was used to remove the dye in two cellulosic sources (filter papers of different brands). The papers were characterized by XRD which confirmed crystallographic profile similar to cellulose. With the aim of optimizing the best conditions, various tests were performed, where the ideal time was 180 minutes for the paper 1 and 240 minutes for the second paper, both by adjusting the pseudo second-order model. The other parameters studied was the pH, adsorbate-adsorbent systems which have maximum adsorption capacity of 2.76 mg / g at pH 2.02 and 2 mg / g at pH 11 for the paper 1 and 10.57 mg / g pH 4 and 2 mg / g at pH 11 for the paper 2. Both adsorbents had the best fit to the Langmuir model in pHs 2 and 11 at the temperature of 298 K.

Abstract: The aim of this work is to present experimental results related to the use of calcium carbonate as pore generating agent. Four compositions containing 20 wt.% of limestone were used and characterized chemically and thermally. Each composition was homogenized in a porcelain ball mill, dried in a laboratory drier, humidified at 7 wt.%, and pressed in an uniaxial hydraulic press. Compacted samples were dried and heat treated with a suitable heating rate for the degasification of calcium carbonate and sintered at 800, 900, and 1050 °C. Sintered samples were characterized to determine the porosity, crystalline phases formed and microstructural features. The results showed that the porosity has increased with the sintering temperature of the compositions increasing due porosity generated by the calcium carbonate degasification and the material expansion.