There are two types of body waves: compressional (P) waves and shear (S) waves. Primary waves (P-waves) travel the fastest, so they arrive at the recording station (seismograph) first. Secondary or shear waves (S-waves) travel slower than P-waves so they arrive second.
Modified frequency modulation (MFM) is an encoding scheme used by PC floppy disk drives and older hard drives.
Quick Answer. SCFM, which stands for standard cubic feet per minute, is a numerical rating that shows the quantity of air flow a pneumatic tool requires to function at peak performance. The actual value varies based on the pressure exerted by the air in the compressor, which is typically measured in pounds per inch.