Hot Particles

Hot Particles

 

atoms or free radicals with energies greater than the energy of thermal motion.

Hot atoms, or energy recoil atoms, are formed in nuclear reactions; hot free radicals arise in photolysis, radiolysis. and electric discharge. The excess energy can be from several electron volts to hundreds of thousands. In collisions the energy of hot particles is either dissipated or expended in chemical conversions, in which reactions can take place that are thermodynamically impossible for ordinary particles.

Hot particles arise in the atmosphere through the testing of atomic weapons and other artificial or natural radioactive processes. The number of hot particles in the atmosphere is infinitesimal—one per hundreds of thousands of cubic meters of air—but their radioactivity is high—from 0.37 disintegrations per sec to 370 disintegrations per sec (from 10−11 to 10−8 curies per particle). In contact with body tissues (primarily of the gastrointestinal tract, respiratory passages, and skin), hot particles can cause the appearance of intense irradiation zones (where, within a radius of a few dozen microns, the total dose absorbed exceeds 10 joules per kg [1,000 rad]), and there is local skin destruction.

References in periodicals archive ?
Once such a model has been established it can then be used to estimate the impact of such variables as fluidization velocities, bed heights, and the relative volume of the charge of hot particles.
Temperature profiles were measured in a fluidized bed of particles following the release of a charge of hot particles.
A 1987 NRC bulletin describes tiny, extremely hot particles less than one millimeter in any direction (called radioactive fleas) that can cause serious damage to people who accidentally touch them.
Crossing into interstellar space would mean a sudden drop in the density of hot particles of the heliosheath and an increase in the density of cold particles of the interstellar plasma.
Hot particles of plutonium and ruthenium had been reported in Sweden that day.
The seven-foot arm holds a bell-shaped extraction hood with an integrated 360-degree handle for easy maneuvering, and an ember catcher prevents hot particles from reaching the filter.
Infrared sensors detect spark, embers or hot particles and trigger countermeasures to extinguish or divert the hazards within milliseconds.
Black holes lie at the centres of almost all galaxies and can spit out incredibly hot particles at high energies that prevent intergalactic gases from cooling and forming new stars in the outer galaxy.
Black holes lie at the centres of almost all galaxies, and can spit out incredibly hot particles at high energies that prevent intergalactic gases from cooling and forming new stars in the outer galaxy.
Those hot particles burn through the outer membrane of the Salmonella, killing the bacteria.
We are discovering hot particles everywhere in Japan, even in Tokyo," he said.
Only heat transfer from the hot particles to the cold particles is calculated.