Roentgen (unit) this derivative quantity the roentgen equivalent physical (rep) to distinguish it from the ICR roentgen. The introduction of the roentgen measurement unit, which relied upon measuring the ionisation of air, replaced earlier less accurate practices that relied on timed exposure, film exposure, or fluorescence. This led the way to setting exposure limits,and the National Council on Radiation Protection and Measurements of the United States established the first formal dose limit in 1931 as 0.1 roentgen per day. The International X-ray and Radium Protection Committee, now known as the International Commission on Radiological Protection (ICRP) soon followed with a limit of
Nordic Society for Invention and Discovery to 7 cm) above the ground. The levitation is provided by six pairs of neodymium magnets. Nordic Society for Invention and Discovery Nordic Society for Invention and Discovery is a Scandinavian invention lab, founded in 2013 by Per Cromwell and Tomas Mazetti. No More Woof is a device aiming to translate dogs thoughts into human language using electroencephalography sensoring. An experimental hockey puck inspired by the forms of the Finnish architect Alvar Aalto , researching what happens if the hockey puck isn't round. It's designed with the goal to maximize randomness and have been tested by hockey teams as Swedish