Abstract: The invention relates to wood preservation systems which employ impregnating agents comprising halogenated tannin extracts from plant species which are relatively more resistant to fungi, weathering, rotting, insect attack, etc. Materials contained within the tannin extracts are converted to halogenated substances which are absorbed by the wood species to be treated. The halogenated extract materials can be used with or without other treatment agents (e.g., fixatives or metal salts). Bromine is the preferred halogen material, with optimum treatment occurring when the bromine concentration in the extract exceeds about 2% (most preferably, about 4-5%).

Abstract: A noise attenuation barrier for control of noise along expressway or other noise sources is provided in which the panel sections are suspended on vertical posts installed in earth berms. The bottoms of the panels, which are shaped to match the contour of the berm are partly buried in a particulate, sound-absorbing layer. The panels include an imperforate rear wall, spaced away from which is a sound-absorbing layer held in place by edge strips that are fit over the tops and bottoms of the layer before it is put in place.