SI base unit units are written in lowercase, except the symbols of those named after a person, which are written with an initial capital letter. For example, the "metre" (US English: "meter") has the symbol m, but the "kelvin" has symbol K, because it is named after Lord Kelvin and the "ampere" with symbol A is named after André-Marie Ampère. Several other units, such as the litre (US English: "liter"), are formally not part of the SI, but are accepted for use with SI. New definitions of the base units were approved on 16 November 2018, to take effect 20 May 2019. The
Khai Si Khai Si Khai Si () is a sub-district ("tambon") in Mueang Bueng Kan District, in Bueng Kan Province, northeastern Thailand. As of 2012, it had a population of 5,294 people. It lies on Highway 212 and the Mekong River and border with Laos, west of Bueng Kan and east of Ho Kham. The sub-district was created in 1979, when nine administrative villages were split from Nong Sawang sub-district (then still named Nong Kheng) to form the new sub-district. The sub-district is divided into 10 administrative villages ("muban"). The sub-district municipality Khai Si is the local government unit responsible for the