To detect heart sounds, the patient should be lying down and examined in a quiet room. Left-sided S3 is best heard at the apex of the heart (the lower pointed end of the heart) with the patient lying on his left side. It is a low-pitched sound and heard best using the bell of the stethoscope with light pressure.
Adorable animal families that will make you aww. Polystyrene is a type of polymer with thermoplastic properties produced from the petroleum-derived monomer, styrene. In solid form, it is a colorless and rigid plastic, but it may also be returned to a liquid state by heating, and used again for molding or extrusion.
Polystyrene, which already had been invented, was a good insulator but too brittle. McIntire tried to make a new rubber-like polymer by combining styrene with a volatile liquid called isobutylene under pressure. The result was a foam polystyrene with bubble, and was 30 times lighter than regular polystyrene. The Dow Chemical Company introduced Styrofoam products to the United State in 1954. How Are Foamed Polystyrene or Styrofoam Products Made. Foamed polystyrene starts as small spherical beads that contain an expanding agent called hydrocarbon.