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Encyclopedia of Global Resources part 93 provides a wide variety of perspectives on both traditional and more recent views of Earth's resources. It serves as a bridge connecting the domains of resource exploitation, environmentalism, geology, and biology, and it explains their interrelationships in terms that students and other nonspecialists can understand. The articles in this set are extremely diverse, with articles covering soil, fisheries, forests, aluminum, the Industrial Revolution, the U.S. Department of the Interior, the hydrologic cycle, glass, and placer mineral deposits. . | 848 Oceanography Global Resources passages facing the waves. In both cases the waves alternately push air out and suck it in. Both processes run turbines at high speed. Extensive work on airpressure designs has been done by the British the Norwegians and the Japanese who tested the Kaimei an 80-meter ship with a number of chambers for testing various turbine designs in the 1970 s. In the 1980 sand 1990 s the Japanese worked on the Mighty Whale project which consists of near-shore floating structures with three large air chambers that convert wave energy into pneumatic energy. Directly harnessing wave motion has some advantages to offset the slow motion and exposure of moving parts. The necessary equipment can be much smaller thus cheaper per unit of electricity generated than the other schemes. For many years Japanese buoys have used pendulums and pulling units to power lights and horns. Scaling these units to larger sizes is difficult and expensive. Experimental units have used hinges between rafts Cockerell s design nodding duck cam-shaped floats to activate rotary hydraulic pumps to turn a generator Salter s design paddles on rollers and many other techniques. In 2008 the world s first commercial-scale wavepower station went live off the coast of Portugal. This British-designed and Portugese-financed station is about 5 kilometers off the northern coast of Portugal and consists of several semisubmerged 142-meter-long 3.5-meter-diameter snakes of carbon steel each with four articulated sections. The wave action drives hydraulic rams in the snake s hinges creating energy that generators convert to electricity which is relayed to a substation in Portugal via seabed cables. At peak output three machines can generate 2.25 megawatts which is enough to serve fifteen hundred family homes for a year. Once produced in quantity ocean wave power may have economics similar to hydroelectric plants expensive to build but inexpensive overall because of low operating costs. .
