Aswan spelled "Assuan". Aswan is the ancient city of Swenett, later known as Syene, which in antiquity was the frontier town of Ancient Egypt facing the south. Swenett is supposed to have derived its name from an Egyptian goddess with the same name. This goddess later was identified as Eileithyia by the Greeks and Lucina by the Romans during their occupation of Ancient Egypt because of the similar association of their goddesses with childbirth, and of which the import is "the opener". The ancient name of the city also is said to be derived from the Egyptian symbol for "trade", or
Hydropower policy in the United States of 90% efficiency. More importantly, Francis's mathematical and graphical calculation methods advanced turbine design and engineering and allowed confident design of high efficiency turbines to exactly match a site's flow conditions. In the 1870s and deriving from uses in the mining industry, the high efficiency Pelton wheel impulse turbine was developed to use hydropower under very different flow and pressure conditions. Advances in dam design also progressed, with the completion of Old Aswan Dam being considered a milestone of engineering over nature. At the time of its construction, nothing of such scale had ever been attempted: it also became one