Convert from barn to dunum, dunham

Unit Definition (barn)
The Barn is a slightly humorous unit of area used in nuclear physics. When atoms are bombarded with smaller particles such as electrons, the electrons are scattered as if the nucleus of the atom was a tiny solid object. The barn is used to express the apparent cross-sectional area of this scattering object. One barn is equal to 1E-28 square meters. Using this unit, physicists can say that such and such a nucleus is "as big as a barn", or 10 barns, or whatever. The proper SI unit to use for these measurements is the square femtometer (fm²); one barn equals 100 fm².

Unit Definition (dunum, dunham)
The Dunum is a traditional unit of land area in the Middle East and the Balkans. The unit is of Turkish origin, but it seems to be obsolete in modern Turkey. As it is commonly used today in Israel and Palestine and in Croatia and other areas of the former Yugoslavia, the dunum is a metric unit equal to 1000 square meters or 0.1 hectare (about 0.2471 acre). The traditional size seems to have been around 900 square meters. In Mesopotamia and Arabia, the dunum was a larger unit, traditionally in the range of 2500 to 4000 square meters. In modern Iraq, the dunum is now standardized at 2500 square meters (about 0.6179 acre).