The multi-spectral imaging system for real-time measurement of combustion efficiency of an industrial flare is provided. The ceramic layer includes a first powder, a second powder, and a third powder. Solar cells are disposed on the edge surfaces. The policy may be expressed as data in a policy expression language that can be consumed at runtime, which provides for flexible and efficient changing of issuing policy. The hierarchical surfaces can be fabricated using biological nanostructures, such as viruses as a self-assembled nanoscale template.