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The critical mass for lower-grade uranium depends strongly on the grade: with 45% 235 U, the bare-sphere critical mass is around 185 kilograms (408 lb); with 19.75% 235 U it is over 780 kilograms (1,720 lb); and with 15% 235 U, it is well over 1,350 kilograms (2,980 lb). In all of these cases, the use of a neutron reflector like beryllium can ...
Critical Mass Energy Project, an anti-nuclear umbrella group founded by Ralph Nader Critical Mass Journal, published in 1977 by the Critical Mass Energy Project; Critical Mass, a co-working center sponsored by the New England Venture Capital Association; Critical Mass, a robotics team of the Dwight-Englewood School in Englewood, New Jersey
The common symbols are j, J, φ, or Φ, sometimes with subscript m to indicate mass is the flowing quantity. Its SI units are kg s−1 m−2. mass moment of inertia A property of a distribution of mass in space that measures its resistance to rotational acceleration about an axis. mass number. Also called atomic mass number or nucleon number.
In social dynamics, critical mass is a sufficient number of adopters of a new idea, technology or innovation in a social system so that the rate of adoption becomes self-sustaining and creates further growth. The point at which critical mass is achieved is sometimes referred to as a threshold within the threshold model of statistical modeling.
The critical point is defined by the intersection of a critical temperature, T c, and a critical pressure, p c; ... A synonym for molar mass and molecular weight, ...
The Tipping Point: How Little Things Can Make a Big Difference is the debut book by Malcolm Gladwell, first published by Little, Brown in 2000. Gladwell defines a tipping point as "the moment of critical mass, the threshold, the boiling point."
In other words, in a critical mass, the number of neutrons emitted over time, exactly equals the number of neutrons captured by another nucleus or lost to the environment. If the mass is supercritical, the number of neutrons emitted per unit time exceeds those absorbed or lost, resulting in a cascade of nuclear fissions at increasing rate.
The critical mass for any material is the smallest amount needed for a sustained nuclear chain reaction. Moreover, different isotopes have different critical masses, and the critical mass for many radioactive isotopes is infinite, because the mode of decay of one atom cannot induce similar decay of more than one neighboring atom.