Homo ergaster may have been the first human species to leave Africa and fossil remains show this species had expanded its range into southern Eurasia by 1.75 million years ago. Their descendents, Homo erectus, then spread eastward and were established in South East Asia by at least 1.6 million years ago. However, an alternate theory proposes that hominins migrated out of Africa before Homo ergaster evolved, possibly about 2 million years ago, prior to the earliest dates of Homo erectus in Asia.
Wiktionary (0.00 / 0 votes) Rate this definition: fume (Noun). A gas or vapour/vapor that smells strongly or is dangerous to inhale. Fumes are solid particles formed by condensation from the gaseous state, e.g. metal oxides from volatilized metals.They can flocculate and coalesce.Their particle size is between 0.1 and 1 micron. gas or vapour/vapor that smells strongly or is dangerous to inhale. Fumes are solid particles formed by condensation from the gaseous state, e.g. metal oxides from volatilized metals. They can flocculate and coalesce. Their particle size is between 0.1 and 1 micron.
Silica fume is a byproduct of producing silicon metal or ferrosilicon alloys. One of the most beneficial uses for silica fume is in concrete. Because of its chemical and physical properties, it is a very reactive pozzolan.Concrete containing silica fume can have very high strength and can be very durable.ilica fume is a byproduct of producing silicon metal or ferrosilicon alloys. One of the most beneficial uses for silica fume is in concrete. Because of its chemical and physical properties, it is a very reactive pozzolan.