Specific activity several other biomedical applications. Specific activity Specific activity is the activity per quantity of a radionuclide and is a physical property of that radionuclide. Activity is a quantity related to radioactivity. The SI unit of activity is the becquerel (Bq), equal to one reciprocal second. The becquerel is defined as the number of radioactive transformations per second that occur in a particular radioactive isotope. Its related non-SI unit equivalent is the Curie (Ci) which is transformations per second. Since the probability of radioactive decay for a given radionuclide is a fixed physical quantity (with some slight exceptions, see changing decay
Barrel (unit) tankers. In the United States, the 42-US-gallon size of barrel as a unit of measure is largely confined to the oil industry, while different sizes of barrel are used in other industries. Nearly all other countries use the metric system. The abbreviations Mbbl and MMbbl refer to one thousand and one million barrels, respectively. These are derived from the Latin "mille" meaning "thousand". This is different from the SI convention where "M" stands for the Greek "mega", meaning "million". Outside of the oil industry, the unit Mbbl (megabarrel) can sometimes stand for one million barrels. The "b" may have been