(February 2014) Allusion is a figure of speech, in which one refers covertly or indirectly to an object or circumstance from an external context. It is left to the audience to make the connection; where the connection is directly and explicitly stated (as opposed to indirectly implied) by the author, it is instead usually termed a reference.
Titanium metal connects well with bone, so it has found surgical applications such as in joint replacements (especially hip joints) and tooth implants. The largest use of titanium is in the form of titanium(IV) oxide. It is extensively used as a pigment in house paint, artistsâ paint, plastics, enamels and paper.
This metal is found in meteorites and has been detected in the sun and in M-type stars. Rocks brought back from the moon during the Apollo 17 mission are composed of 12.1% TiO2. Titanium is also found in coal ash, plants, and even the human body (while harmless, it is not believed to be an essential element).