Surface Plot of Dini's Surface (Parametric Surface)

Surface plot of Dini's surface is demonstrated using mesh command

Dini's surface is given by the following parametric equation:
x=acos(u)sin(v);
y=asin(u)sin(v);
z=a(cos(v)+log(tan(0.5v)))+bu;
These equation are surface plotted using mesh command.
Ref: http://en.wikipedia.org/wiki/Dini's_surface