input: If the room is empty and the sound absorption level is determined mainly from the absorption of the ceiling the floor and the walls then A aceiling x Sceiling afloor x Sfloor awall x Swall where a is the sound absorption factor and S is the surface for the respective area of the room We have assumed that all the walls have the same absorption factor
fixed: If the room is empty and the sound absorption level is determined mainly from the absorption of the ceiling, the floor and the walls, then A = aceiling x Sceiling + afloor x Sfloor + awall x Swall where a is the sound absorption factor and S is the surface for the respective area of the room. We have assumed that all the walls have the same absorption factor.

input: The yeast is also used to make alcohol
fixed: The yeast is also used to make alcohol.

input: Much of Frlichs earlier work was for various calendars in Leipzig and Dresden
fixed: Much of Frlich's earlier work was for various calendars in Leipzig and Dresden.

input: Playing with the materials
fixed:
Playing with the materials.