“…Mathematical models of HL usually involve functions such as exponential [13], polynomial [14], [15], and rational [16]- [19], then functions represented via Fourier series [20], Langevin [21], [22], Frolich [19], Brillouin function [21], and modified Brillouin function [23], hyperbolic tangent [24], and arcus tangent function [19], [21], [25]- [28]. Takacs model [29], [11] is based on the linear combination of the hyperbolic tangent and linear function.…”