Pyrolysis oil are affected by temperature, reaction time, algae species, algae concentration, reaction atmosphere, and catalysts, in subcritical water reaction conditions. Bio-oil typically requires significant additional treatment to render it suitable as a refinery feedstock to replace crude oil derived from petroleum, coal-oil, or coal-tar. Tar is a black mixture of hydrocarbons and free carbon obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. Wood-tar creosote is a colourless to yellowish greasy liquid with a smoky odor, produces a sooty flame when burned, and has a burned taste. It is
English words of Greek origin πρεσβύτερος ("presbýteros" 'elder'), and "church" < Old English "cirice", "circe" < probably κυριακή [οἰκία] ("kȳriakḗ [oikía]" 'lord's [house]'). In some cases, the orthography of these words was later changed to reflect the Greek – and Latin – spelling: "e.g.", "quire" was respelled as "choir" in the 17th century. Sometimes this was done incorrectly: "ache" is from a Germanic root; the spelling "ache" reflects Samuel Johnson's incorrect etymology from Greek ἄχος. Many more words were borrowed by scholars writing in Medieval and Renaissance Latin. Some words were borrowed in essentially their original meaning, often transmitted through classical Latin: "topic", "type", "physics",