The formula used to compute airwattage differs between vacuum cleaner manufacturers. All printing occurs without the use of vacuum or pressure chambers. Superatmospheric cycles&colon; achieved with a vacuum pump. He built his higher order filters from 2-pole filters separated by vacuum tube amplifiers. It used a large number of valves (vacuum tubes). The instrument read punched paper tape that controlled an analog synthesizer containing 750 vacuum tubes. This consisted of radio-frequency source fed through a coil spread along the vacuum chamber. IC chips reversed the economics of radio design used with vacuum tube receivers. They do this at the expense of the seal between the vacuum and their exhaust. Thus strong magnetic fields vary the energy contained in the vacuum. Spacing can be either vacuum or dielectric. Synchrotron radiation is created by accelerating free particles in high vacuum. In 1931, a method of packing coffee in a sealed vacuum in cans was introduced. Robotic mice vacuum the home and tidy up. Ice sublimates at this temperature in the near vacuum.