Abstract: Layered assemblies are disclosed, that include a variable transmittance layer having opposing first and second sides; at least a first reflectance color-balancing layer positioned on the first side of the variable transmittance layer; and a transmittance color-balancing layer positioned on the first side or the second side of the variable transmittance layer. The variable transmittance layer may be variable between a dark state and a light state, and may have a dark state transmittance spectrum when in the dark state and a different light state transmittance spectrum when in the light state.

Abstract: Aromatic compounds in small amounts function as antifoulant additives in pyrolysis furnaces which are subjected to elevated temperatures from about 500.degree. C. to about 1200.degree. C. when thermally convening hydrocarbons to ethylene as well as other useful products. These furnaces produce material that deposits and accumulates upon furnace surfaces including furnace radiant coils and transfer line exchangers. The present antifoulant additives inhibit and suppress the formation and deposition of material on furnace surfaces. The present invention is a method for inhibiting the formation of coke on the surfaces of a radiant heating section of a pyrolysis furnace and the surfaces immediately downstream of such section in contact with a hydrocarbon feedstock which comprises decoking the pyrolysis furnace, and prior to processing the hydrocarbon feedstock, adding an inhibiting compound to the pyrolysis furnace.