purify oxygen
31Cryogenic engineering — is a branch of mechanical engineering which deals with cryogenics. and related very low temperature processes such as air liquefaction, cryogenic engines (for rocket propulsion), cryogenic surgery, et cetera. Generally, temperatures below the… …
32Acetic acid — Acetic redirects here. It is not to be confused with Ascetic. Acetic acid …
33Aquatic ecosystem — An aquatic ecosystem is an ecosystem located in water bodies. Communities of organisms that are dependent on each other and on their environment live in aquatic ecosystems. The two main types of aquatic ecosystems are marine ecosystems and… …
34Activated carbon — Activated carbon, also called activated charcoal, activated coal or carbo activatus, is a form of carbon that has been processed to make it extremely porous and thus to have a very large surface area available for adsorption or chemical reactions …
35History of electrochemistry — Electrochemistry, a branch of chemistry, went through several changes during its evolution from early principles related to magnets in the early 16th and 17th centuries, to complex theories involving conductivity, electrical charge and… …
36Lego Rock Raiders — was a Lego theme started 1999, and was discontinued in 2000. Rock Raiders was the only theme in the Lego Underground series. The theme, while short lived, featured sixteen sets and was backed up by numerous story related media, including several… …
37Alchemy in history — Alchemy encompasses several philosophical traditions spanning some four millennia and three continents. These traditions general penchant for cryptic and symbolic language makes it hard to trace their mutual influences and genetic… …
38microbiology — microbiological /muy kroh buy euh loj i keuhl/, microbiologic, adj. microbiologically, adv. microbiologist, n. /muy kroh buy ol euh jee/, n. the branch of biology dealing with the structure, function, uses, and modes of existence of microscopic… …
39Calvin, Melvin — born April 8, 1911, St. Paul, Minn., U.S. died Jan. 8, 1997, Berkeley, Calif. U.S. biochemist. He received his Ph.D. from the University of Minnesota. He developed a system of using the radioactive isotope carbon 14 as a tracer element in his… …
40Alchemy — Alchemist redirects here. For other uses, see Alchemist (disambiguation). For other uses, see Alchemy (disambiguation). Page from alchemic treatise of Ramon Llull, 16th century Alchemy is an influential philosophical tradition whose early… …
