Pietermans Website seems to be down so here is the material graph again. I also added UV Animation/Tiling:
By the way: To avoid this ugly pixel line:
You can manually set to use always the highest mipmap. This will fix it. But careful: this is not good for performance nor quality when you see your texture from distance!
The reason is, that for choosing a mipmap, the graphic card looks at two neightbor-pixels and compares the UVs. If the coordinates are far from eachother, the engine chooses a smaller mipmap (because it seems that the polygon/pixels are far in the back of the scene). For us this means, that at the position where our texture “tiles” over the radial coordinates, there’s a big jump in uv-coordinates and because of that the engine chooses the smallest mipmap for those pixels.