1) In general, an intermediary is a person or service that is involved as a third party between two or more end points in a communication or transaction.n the World Wide Web, the role of an intermediary is sometimes said to be no longer necessary as, for example, when you look up legal or medical information directly yourself or when you share files with other Internet users directly (see peer-to-peer).
A roof covers a building or home structure, protecting any belongings found within. There are a large number of materials that can be used to roof a building or home, including several types of metal roofing materials. These materials include steel, aluminum, copper and tin.
Bridge Construction Materials: The traditional building materials for bridges are stones, timber and steel, and more recently reinforced and pre-stressed concrete. For special elements aluminum and its alloys and some types of plastics are used. These materials have different qualities of strength, workability, durability and resistance against corrosion.