The Reconstruction Finance Corporation (RFC) was established during the Hoover administration with the primary objective of providing liquidity to, and restoring confidence in the banking system. The banking system experienced extensive pressure during the economic contraction of 1929-1933.
Typical materials used for electromagnetic shielding include sheet metal, metal screen, and metal foam. Any holes in the shield or mesh must be significantly smaller than the wavelength of the radiation that is being kept out, or the enclosure will not effectively approximate an unbroken conducting surface.
The definition of an electromagnetic wave is one that moves by the power of electric and magnetic fields. An example of an electromagnetic wave is what provides the power in a microwave. a wave propagated through space or matter by oscillating electric and magnetic fields: in a vacuum it travels at the speed of light.