hydraulic empire

Examples of hydraulic empire in the following topics:

• River Valley Civilizations

  • Most notably, these early civilizations were all hydraulic empires.
  • A hydraulic empire (also known as hydraulic despotism, or water monopoly empire) is a social or governmental structure which maintains power through exclusive control over water access.
  • Most hydraulic empires exist in desert regions, but imperial China also had some such characteristics, due to the exacting needs of rice cultivation.
  • The only hydraulic empire to exist in Africa was under the Ajuran State near the Jubba and Shebelle Rivers in the 15th century CE.
  • Hydraulic empires were usually destroyed by foreign conquerors.

• The Sultanates of Somalia

  • From the Middle Ages until when Europeans colonized the territory of today's Somalia, the region was never dominated by a centralized empire, and instead witnessed the development and decline of several powerful trading sultanates whose cultures were deeply rooted in Islam.
  • The Sultanate of Mogadishu was an important trading empire that lasted from the 10th century to the 16th century.
  • Trading routes dating from the ancient and early medieval periods of Somali maritime enterprise were strengthened or re-established, and foreign trade and commerce in the coastal provinces flourished, with ships sailing to and coming from many kingdoms and empires in East Asia, South Asia, Europe, the Near East, North Africa, and East Africa.
  • As a hydraulic empire, the Ajuran monopolized the water resources of the Shebelle and Jubba rivers.

• Pascal's Principle

  • Named after French mathematician Blaise Pascal, who established this important relationship, Pascal's Principle can be used to exploit pressure of a static liquid as a measure of energy per unit volume to perform work in applications such as hydraulic presses.
  • Taking advantage of this phenomenon, hydraulic presses are able to exert a large amount of force requiring a much smaller amount of input force. gives two different types of hydraulic press configurations, the first in which there is no difference in height of the static liquid and the second in which there is a difference in height Δh of the static liquid.
  • Depending on the applied pressure and geometry of the hydraulic press, the magnitude of F2 can be changed.
  • For a hydraulic press, the force multiplication factor is the ratio of the output to the input contact areas.
  • Two different types of hydraulic press configurations, the first in which there is no difference in height of the static liquid and the second in which there is a difference in height Δh of the static liquid.

• The Fall of the Han and the Three Kingdoms Period

  • As the Han Dynasty government weakened over time and ultimately collapsed, the empire fractured into the war-torn Three Kingdoms period.
  • Wei mechanical engineer, Ma Jun, invented a hydraulic-powered, mechanical puppet theatre designed for his emperor.

• Hydraulic Jump

  • We neglect the vertical motion of the fluid and assume that all dimensions are large compared with the depth of the fluid --- this is the hydraulic approximation.
  • We can apply the results from gas dynamics to hydraulics as along as the flow is abiabatic --- no shocks.
  • Such discontinuities are known as hydraulic jumps.

• Flow through a Channel

  • Much of the intuition developed in hydraulics carries over to other fluid systems (even astrophysical ones); furthermore, water running through a channel is something with which most are familiar.
  • Let's write out the Bernoulli equation (divided by $g$ as customary in hydraulics) for the fluid moving along the surface,
  • The quantity $h_0$ is a constant along the surface streamline, and it is so important in hydraulics that it has a special name, specific head.
  • This is a common assumption in hydraulics.

• State Formation

  • Wittfogel argued that most of the earliest states were formed in hydraulic civilizations, by which he meant civilizations where leaders controlled people by controlling the water supply.
  • Modern archaeological and anthropological evidence shows that many early societies were not as centralized, despotic, or unequal as the hydraulic theory would suggest.
  • In hydraulic civilizations, control over water concentrated power in central despotic states.

• Problems

  • When water flows into a bathtub, a circular hydraulic jump forms around the incoming stream of water.

• Poiseuille's Equation and Viscosity

  • Laminar flow is often encountered in common hydraulic systems, such as where fluid flow is through an enclosed, rigid pipe; the fluid is incompressible, has constant viscosity, and the Reynolds number is below this lower critical threshold value.
  • This equation is valid for laminar flow of incompressible fluids only, and may be used to determine a number of properties in the hydraulic system, if the others are known or can be measured.
  • Poiseuille's equation as given in this example (see ) is analogous to Ohm's equation for determining the resistance in an electronic circuit and is of great practical use in hydraulic-circuit analysis.

• The Role of Blood in the Body

  • Hydraulic functions, including the regulation of the colloidal osmotic pressure of blood