Map Based Simulation of Pandemic Influenza Virus Spreading.

A method for forming a layer of very uniform low density foam of uniform thickness on a surface is disclosed. A screen is positioned at a selected distance above a structure surface. The screen is positioned by lowering a tautly stretched screen over a plurality of studs upstanding from the structure surface to a selected height above said surface. A liquid, self-rising foam material is sprayed through the screen onto the structure surface. As the foam rises, it penetrates through the screen, leaving irregular projections above the screen. After the foam cures to at least a self-sustaining state, the screen is stripped away, leaving a uniform foam layer. The foam layer is bonded to the surface as it cures. Since the screen offers very little resistance to the rising foam, the resulting foam layer has a very uniform low density, highly desirable for thermal insulation application.