“…Other variable transformation considered for the approximation of weakly near singular integrals include the radial variable transformation (Hayami and Matsumoto, 1994), the distance transformation (Ma and Kamiya, 2002;Xie et al, 2013) and the sinh transformation (Johnston et al, 2007;Xie et al, 2021). The quadrature scheme presented in Gong et al (2020) combines the benefits of the sinh transformation method and adaptive methods such it is capable of integral kernels of the type 1/r, 1/r 2 and 1/r 3 on near singular elements. Many other quadrature rules for weakly singular integrals on nearly singular elements can be found in the literature as for example the parameterized Gaussian quadrature (Lutz, 1992), line integral approaches (Krishnasamy et al, 1994;Liu, 1998) and analytical (Padhi et al, 2001;Zhou et al, 2008) and semi-analytical methods (Sladek et al, 2001;Niu et al, 2005;Han et al, 2022).…”