RETRACTED: Assessment of hydraulic friction in polypropylene pipes Aybek Arifjanov, Dinislom Atakulov, Sayfiddin Parpiyev, Zaytuna Ibragimova and Bekzod Makhmudov E3S Web Conf., 538 (2024) 01025 Published online: 14 June 2024 DOI: 10.1051/e3sconf/202453801025