Wednesday, December 26, 2007

Electronic Mixer

An electronic mixer is a piece of equipment for mixing two or more electronic signals. There are two basic types of mixer Additive mixers add two signals collectively, and are used for such applications as audio mixing. Multiplying mixers increase the signals together, and produce an output containing both original signals, and new signals that have the sum and difference of the frequency of the original signals.

Additive mixers are generally resistor networks, surrounded by impedance matching and amplification stages.

Multiplying mixers have been completed in a wide variety of ways. The most popular are diode mixers, gilbert cell mixers, diode loop mixers and switching mixers.

Tuesday, December 18, 2007

Heat capacity and heat of vaporization

Water has the second highest specific heat capability of any known chemical compound, after ammonia, as well as a high heat of vaporization (40.65 kJ mol−1), both of which are a result of the extensive hydrogen bonding between its molecules. These two unusual properties permit water to moderate Earth's climate by buffering large fluctuations in temperature.

Thursday, December 13, 2007

Ocean

Ocean (from Okeanos, a Greek god of sea and water; Greek ??ea???) covers almost three quarters (71%) of the surface of the Earth, and almost half of the world's marine waters are over 3000 m deep.

This global, interconnected body of salt water, called the World Ocean, is separated by the continents and archipelagos into the following four bodies, from the largest to the smallest: the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic Ocean, and, according to some authorities such as International Hydrographic Organization(IHO), a fifth ocean, the Southern Ocean.

Tuesday, December 4, 2007

Sea water

Sea water is water commencing a sea or ocean. On usual, sea water in the world's oceans has a salinity of ~3.5%. This means that for each and every 1 liter (1000mL) of sea water there are 35 grams of salts (mostly, but not entirely, sodium chloride) dissolved in it. This can be articulated as 0.6M NaCl. Water with this level of osmolality is, of course, not potable.

Sea water is not homogeneously saline throughout the world. The planet's freshest sea water is in the Gulf of Finland, division of the Baltic Sea. The most saline open sea is the Red Sea, where high temperatures and confined movement result in high rates of surface evaporation and there is little fresh inflow from rivers. The salinity in isolated seas (for example, the Dead Sea) can be significantly greater.

Tuesday, November 27, 2007

Water

Water (from the Old English word wæter; c.f German "Wasser", Danish "Vand", Russian ???? [voda]) is a tasteless, neutral, and nearly colorless (it has a slight hint of blue) substance in its pure form that is essential to all known forms of life and is known also as the most universal solvent. Water is an plentiful substance on Earth. It exists in many places and forms: mostly in the oceans and glacial ice caps, but also as clouds, rain water, rivers, freshwater aquifers, and sea ice. On the planet, water is endlessly moving through the cycle involving evaporation, precipitation, and runoff to the sea.

Water that humans use is called potable water. This natural resource is becoming more limited in certain places as human population in those places increases, and its availability is a major social and economic concern.

Wednesday, November 21, 2007

Amozon River

The Amazon River (occasionally River Amazon; Spanish: Río Amazonas, Portuguese: Rio Amazonas) of South America is one of the two longest rivers on Earth, the additional being the Nile in Africa. The Amazon has by far the greatest entire flow of any river, carrying more than the Mississippi, Nile, and Yangtze rivers combined. Its drainage area, called the Amazon Basin, is the biggest of any river system. The Amazon could be well thought-out the "strongest" (largest volume of water per second).

The measure of fresh water released to the Atlantic Ocean is enormous: up to 300,000 m³ per second in the rainy season. Indeed, the Amazon is answerable for a fifth of the total volume of fresh water entering the oceans worldwide. It is said that offshore of the mouth of the Amazon filtered water can be drawn from the ocean while still out of sight of the coastline, and the salinity of the ocean is notably lower a hundred miles out to sea.

Tuesday, November 13, 2007

Water Injection

The Water Injection technique used in oil production is where water is injected back into the reservoir generally to increase pressure and thereby stimulate production. Water injection wells are naturally found offshore. This method is used to enlarge oil recovery from an existing reservoir- Water is injected to force unrecovered oil out of tank rock and into nearby oil wells. Usually only 30% of the oil in a reservoir can be extracted. With Water Injection that percentage will be higher and the production rate of a reservoir is secure over a long period of time.