Albedo Research showed impacts of over 10%. More recently, the analysis was extended to the effects of spectral bias due to the specular reflectivity of 22 commonly occurring surface materials (both human-made and natural) and analyzes the albedo effects on the performance of seven photovoltaic materials covering three common photovoltaic system topologies: industrial (solar farms), commercial flat rooftops and residential pitched-roof applications. Because forests generally have a low albedo, (the majority of the ultraviolet and visible spectrum is absorbed through photosynthesis), some scientists have suggested that greater heat absorption by trees could offset some of the carbon benefits of afforestation (or
Incompressible surface ∂"D". If "D" were to bound a disk inside "S" (which is always the case if "S" is incompressible, for example), then compressing "S" along "D" would result in a disjoint union of a sphere and a surface homeomorphic to "S". The resulting surface without the sphere might or might not be isotopic to "S". There is also an algebraic version of incompressibility. Suppose formula_4 is a proper embedding of a compact surface in a 3-manifold. Then "S" is "π"-injective (or algebraically incompressible) if the induced map on fundamental groups is injective. In general, every "π"-injective surface is incompressible, but