A horizontal, opaque surface at a steady-state temperature of \(80^{\circ} \mathrm{C}\) is exposed to an airflow having a free stream temperature of \(25^{\circ} \mathrm{C}\) with a convection heat transfer coefficient of \(20 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\). The emissive power of the surface is \(628 \mathrm{~W} / \mathrm{m}^{2}\), the irradiation is \(1380 \mathrm{~W} / \mathrm{m}^{2}\), and the reflectivity is 0.30 . Determine the absorptivity of the surface. Determine the net radiation heat flux for this surface. Is this heat flux to the surface or from the surface? Determine the combined heat flux for the surface. Is this heat flux to the surface or from the surface?