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Liquid oxygen has a clear cyan color and is strongly paramagnetic: it can be suspended between the poles of a powerful horseshoe magnet. [2] Liquid oxygen has a density of 1.141 kg/L (1.141 g/ml), slightly denser than liquid water, and is cryogenic with a freezing point of 54.36 K (−218.79 °C; −361.82 °F) and a boiling point of 90.19 K (−182.96 °C; −297.33 °F) at 1 bar (14.5 psi).
The word paper comes from the Greek term for the ancient Egyptian writing material called papyrus, which was formed from beaten strips of papyrus plants. Papyrus was produced in Egypt as early as 3000 BC and was sold to ancient Greece and Rome. Egyptians were the first to use reed pens and Ink which they used to write on papyrus.
Diversion dam — The first Diversion dam is Sadd el-Kafara Dam built in Egypt around 2700 B.C. [19]; Noria — Norias appeared in Egypt in the 4th Century B.C. [20]; Beekeeping — domesticated Beekeeping was first recorded in ancient Egypt around 2600 B.C. [21] [22] as well as the first use of smoke while extracting the honey from bee nests.
Ancient Egyptian sundial (c. 1500 BC), from the Valley of the Kings, used for measuring work hour. Daytime divided into 12 parts. The ancient Egyptians were one of the first cultures to widely divide days into generally agreed-upon equal parts, using early timekeeping devices such as sundials, shadow clocks, and merkhets (plumb-lines used by early astronomers).
This is called a reducing firing. In an oxidating firing by contrast, a continuous supply of oxygen is maintained. The iron in the clay absorbs oxygen and becomes the red or red-brown iron(III) oxide. The resulting pottery has a red-brown colour. [25] The simplest and earliest firing method is the open fire. The vessel to be fired is covered ...
A cryogenic gas plant is an industrial facility that creates molecular oxygen, molecular nitrogen, argon, krypton, helium, and xenon at relatively high purity. [1] As air is made up of nitrogen, the most common gas in the atmosphere, at 78%, with oxygen at 19%, and argon at 1%, with trace gasses making up the rest, cryogenic gas plants separate air inside a distillation column at cryogenic ...
In materials science, liquefaction [1] is a process that generates a liquid from a solid or a gas [2] or that generates a non-liquid phase which behaves in accordance with fluid dynamics. [3] It occurs both naturally and artificially. As an example of the latter, a "major commercial application of liquefaction is the liquefaction of air to ...
Prehistoric Egypt and Predynastic Egypt was the period of time starting at the first human settlement and ending at the First Dynasty of Egypt around 3100 BC.. At the end of prehistory, "Predynastic Egypt" is traditionally defined as the period from the final part of the Neolithic period beginning c. 6210 BC to the end of the Naqada III period c. 3000 BC.