It was renamed Functional Discourse Grammar in the 1990s, but the theory can go by either name. This theory is called functional because it states that all constituents, whether affixes, words, phrases, or sentences, have semantic, syntactic, and pragmatic functions.he most famous of these is Systemic Functional Grammar, which was first published by British linguist Michael Halliday in 1961. Other functional grammars include Danish Functional Linguistics, lexical functional grammar, and Role and Reference Grammar.
The head of a Hemispherical combustion chamber. A hemispherical combustion chamber is a type of combustion chamber in a reciprocating internal combustion engine with a domed cylinder head. The hemispherical shape provides a number of advantages over a reverse-flow cylinder head but comes up short in others, particularly in carbureted engines.
The Space Power Facility at NASA Glenn Research Center's Plum Brook Station in Sandusky, Ohio, houses the world's largest vacuum chamber. It measures 100 feet in diameter and is a towering 122 feet tall. The facility is currently undergoing construction to support Orion crew exploration vehicle testing in 2010.