Search

The use of modern materials in sports, in terms of chemical composition and surface texture, entails both progress in results and an increasing discrepancy in the technical parameters of the equipment used. This paper aims to demonstrate the differences between balls admitted to a league and world championships in composition, surface texture, and the influence of these parameters on the water polo game. This research compared two new balls produced by top companies producing sports accessories (Kap 7 and Mikasa). To obtain the goal, the measurement of the contact angle, analysis of the material using Fourier-transform infrared spectroscopy, and optical microscopic evaluation were used. The analysis of the surface free energy shows significant differences (Kap 7 32.16 mJ/m2, Mikasa 36.48 mJ/m2). In the case of both balls, anisotropies of the structure of the furrows were observed, however, the Mikasa ball is slightly more homogeneous than the Kap 7 ball. The obtained results from the analysis of the contact angle, as well as the composition and real feedback from the players, indicated the need to standardize the material aspect of the regulations so that the sports results are repeatable every time. [ABSTRACT FROM AUTHOR]

Many factors contribute to the high durability of anti-corrosion coatings. The most frequently mentioned are: appropriate protection design selected for the operating conditions, type of protection-type of metal and/or coatings, surface preparation, and proper application. Particular emphasis is placed on the type of protective materials. A lot of research is also carried out in this direction. In this article, we want to show that the standard protection with an epoxy/polyurethane system with thickness as recommended in ISO 12944-5: 2019, without special active fillers, is able to ensure high durability in a C4/C5 environment. This is confirmed by the presented results of electrochemical analysis, visual evaluation of coatings and adhesion of coatings and allows the use of well-known, inexpensive paint systems, assuming greater emphasis on their proper application. The results of the assessment of coating systems on bridges were used for comparison with the results obtained in various types of accelerated tests of the same coating systems and to make the selection of the optimal version of the laboratory tests. [ABSTRACT FROM AUTHOR]