Neutron star concluded that the radiation comes from a neutron star at the stage of accretion. In 1967, Jocelyn Bell Burnell and Antony Hewish discovered regular radio pulses from PSR B1919+21. This pulsar was later interpreted as an isolated, rotating neutron star. The energy source of the pulsar is the rotational energy of the neutron star. The majority of known neutron stars (about 2000, as of 2010) have been discovered as pulsars, emitting regular radio pulses. In 1971, Riccardo Giacconi, Herbert Gursky, Ed Kellogg, R. Levinson, E. Schreier, and H. Tananbaum discovered 4.8 second pulsations in an X-ray source in the constellation
Chilled beam metal pipe of water just in diameter can carry as much energy as an metal duct of air. This means that chilled beam HVAC systems require much less energy to provide the same heating and cooling effect as a traditional air HVAC system. Chilled beam cooling systems require water to be treated by heating and cooling systems. Generally, water in a passive chilled beam system is cooled to about . In active chilled beam heating systems, water temperature is usually . (Chilled beam heating systems usually cannot rely solely on convection, however, and often require a fan-driven primary air circulation