Mathematical Methods -- Passive Scalar Diffusion as a Damped Wave -- Extremalizing Vector Fields as Guides Toward Understanding Properties of Turbulence -- Low-Wavenumber Forcing and Turbulent Energy Dissipation -- New Potential Symmetries for a Generalised Inhomogeneus Nonlinear Diffusion Equation -- DNS and New Scaling Laws of ZPG Turbulent Boundary Layer Flow -- Linear Instability of a Slowl…