barn


Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Acronyms, Idioms, Wikipedia.

barn,

abbr. b, in physics, unit of nuclear cross section, i.e., the effective target presented by a nucleusnucleus,
in physics, the extremely dense central core of an atom. The Nature of the Nucleus
Composition

Atomic nuclei are composed of two types of particles, protons and neutrons, which are collectively known as nucleons.
..... Click the link for more information.
 for collisions leading to nuclear reactions; it is equal to 10−24 square centimeters. The barn is approximately the size of the geometric cross section of an atomic nucleus; the term was coined because an effective cross section that large would present a target "as big as a barn," i.e., an easy target for nuclear bombardment. In practice, effective cross sections of nuclei for many reactions are measured in millibarns (10−3 barn) because, for most interactions, only a small fraction of collisions cause reactions.

Barn

A building for housing animals and storing farm equipment, hay, and other agricultural produce.

Barn

 

a unit of effective cross-sectional area of nuclear processes. One barn = 10–24 cm2 = 10–28 m2. Selection of this unit is related to the fact that the geometric cross sections of atomic nuclei are on the order of 10–24 cm2 in size. The magnitudes of the majority of cross sections of nuclear reactions usually lie in the range between 10–22 cm2 and 10–27cm2. For this reason fractional and multiple barn units are used, such as millibarn (10–27 cm2), microbarn (10–30 cm2), and megabarn (10–18 cm2).

barn

[′bärn]
(agriculture)
A farm building used for storage of agricultural products and equipment or for housing farm animals.
(nuclear physics)
A unit of area equal to 10-24 square centimeter; used in specifying nuclear cross sections. Symbolized b.

barn

A farm building, most often rectangular (but occasionally circular or polygonal), for housing farm animals, storing farm equipment, threshing grain, and storing grain, hay, and other agricultural produce. Barn construction usually depends on such factors as the local climate and traditions, building materials available, the skills and time required for construction, and the cost. For some examples, see bank barn, basement barn, circular barn, connected barn, Connecticut barn, crib barn, double barn, Dutch barn, English barn, forebay barn, four-crib barn, German barn, hex barn, New England connected barn, octagon barn, Pennsylvania barn, Pennsylvania Dutch barn, potato barn, raised barn, round barn, side-hill barn, Sweitzer barn, Swiss barn, three-bay barn, tobacco barn, Yankee barn.

barn

1
US and Canadian a large shed for sheltering railroad cars, trucks, etc.

barn

2
a unit of nuclear cross section equal to 10--28 square metre.
References in periodicals archive ?
Honored guests were given an exclusive walkthrough of the Spring 2018 collections featuring Pottery Barn, Pottery Barn Kids and West Elm.
Barn doors are also perfect to hide a media area, or even a flat-screen TV, should you wish to cover it when it is not in use.
Some people think that socialized barn cats will want to come into the house, but that's not usually the case.
Conroy said Boot Barn acquired the CountryOutfitter.
The Barn at Brynich | Where: Brecon The Barn at Brynich is a Grade II listed building, which has its original oak beams, open fire place and flagstone floor.
Marta brings 25 years of experience in specialty retail and direct marketing to leading the Pottery Barn brand and its vision of serving as the most inspiring American home design resource," said Alber.
Building a barn could take years, with frames being laid out by one generation, while the next put the final hinges on the doors.
Barns mean different things to different people," muses Brad Klodt, who moved an 1895 barn to his farm in 2002, and who is active in the Van Buren County barns program.
The Rundles explore the concept of what barn settings, styles, methods and materials tell us about the people who built them, the life they lived, and the role these vanishing country cathedrals played in the settling and building of a growing nation.
Last year, the wildlife trust received only 19 barn owl sightings.
Francis Watson Armstrong, owner of Bamburgh Castle, said: "Far from being a feather-brained scheme, we were very keen at Bamburgh to support a project that protects and conserves the majestic barn owl - my favourite national bird species.
Other than a reference to unpublished data mentioned by Martin and Martin (1978), there are no data on the relative reproductive performance of barn and cave swallows when nesting together, nor is there any further evidence on whether cave swallows are having a negative impact on barn swallows outside of south and southwest Texas.