At first, visualising an invisible substance of unknown composition seems like an impossible task.
He said he and three other recruits were given a succession of injections in both arms of a drug that was red, but of unknown composition.
Chemists refer to published libraries of chemical shifts both to identify the substances present in samples of unknown composition and to infer the structures of newly synthesized molecules.
Mr. Dawood is accused of threatening to use a weapon of mass destruction by depositing a powder of unknown composition into a mailbox at the height of anthrax fears.
But the unknown composition and effects of many legal highs means the health consequences have been particularly severe, with 19 deaths in prisons linked to legal highs over the last two years.
Approximately one quarter of the mass-energy of the universe is believed to be comprised of dark matter, a substance of unknown composition, which may be a source of cosmic rays.
"It beggars belief that you can have a rechargeable battery device heating up a liquid of unknown composition, which you use at your mouth for hours at [sic] end, with no safety standards at all," Quit Victoria director Dr Sarah White said on Monday.
The ordinary matter of the universe, astronomers say, is engulfed in clouds of dark matter of unknown composition or origin, which in turn is engulfed in something called dark energy, which may be wrenching space apart, in an einsteinianly plausible way.
And it's yet another level of experience to realize that those stars account for less than 4 percent of what's out there — the rest being of an unknown composition, so-called dark matter and energy, which researchers are now trying to divine.
The sample represents a mixture of unknown composition with over eighty potential signals.
The accurate determination of mercury (II) ions in samples of unknown composition is demonstrated with a fortified tap water sample.
