It is important not to confuse IMC with IFR (instrument flight rules) â IMC describes the actual weather conditions, while IFR describes the rules under which the aircraft is flying. Aircraft can (and often do) fly IFR in clear weather, for operational reasons or when flying in airspace where flight under VFR is not permitted; indeed by far the majority of commercial flights are operated solely under IFR.
Norbert Rillieux. Norbert Rillieux (1806-1894) was the inventor of the multiple-effect vacuum evaporator, which revolutionized the processing of sugar. He gained recognition as one of the prime architects of the modern sugar industry.
Invented by Sir James Dewar in 1892, the vacuum flask consists of two flasks, placed one within the other and joined at the neck. The gap between the two flasks is partially evacuated of air, creating a near-vacuum which significantly reduces heat transfer by conduction or convection.