doughnut(redirected from Doughnut hole)
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doughnut(esp US), donut
anything shaped like a ring, such as the reaction vessel of a thermonuclear reactor
Also spelled donut.
The toroidal vacuum chamber in which electrons are accelerated in a betatron or synchrotron. Also known as toroid.
An assembly of enriched fissionable material, often doughnut-shaped, used in a thermal reactor to provide a local increase in fast neutron flux for experimental purposes.
A ring of wedges or a threaded, tapered ring that supports a pipe string.
concrete collar, doughnut
A collar of reinforced concrete which is placed around an existing column so that it can be jacked up; the shrinkage of the concrete causes it to grip the column firmly.