Rapid Prototyping involved creating a working model of various parts of the system at a very early stage, after a relatively short investigation. The method used in building it is usually quite informal, the most important factor being the speed with which the model is provided.
There are water-and solvent-based -- also called oil-based -- polyurethane varnishes. Water-based polyurethanes are more environmentally friendly and safer to use than solvent-based, but they are not as resistant to wear and tear as solvent-based products.
Adsorption on activated carbon is currently the most frequently used technology for removing organic pollutants from aqueous industrial sludge, surface waters and drinking water. Methyl tert-butyl ether (MTBE) is an organic pollutants used mainly as a fuel component in fuel if gasoline engine and also as a solvent.