Square miles

Twenty isotopes are known. Radon-22, from radium, has a half-life of 3.823 days and is an alpha emitter Radon-220, emanating naturally from thorium and called thoron, has a half-life of 55.6 s and is also an alpha emitter. Radon-219 emanates from actinium and is called actinon. It has a half-life of 3.96 s and is also an alpha emitter. It is estimated that every square mile of soil to a depth of 6 inches contains about 1 g of radium, which releases radon in tiny amounts into the atmosphere. Radon is present in some spring waters, such as those at Hot Springs, Arkansas. 

Nofe Calculated from data ia Table 1 usiag the equatioa tons per square miles = annual averageconstituent concentration in milligrams per liter x annual average stream discharge in cubic feet ... 

Brazil. Brazil has two principal crystalline flake mines, a smaller one at Itapecerica and a larger one at Pedra Azul, both in Minas Gerais State. Both mines are owned by Nacional de Grafite Ltd. The ore at Itapecerica averages 20% carbon and is surface mined from a number of pockets spread over an area of ca 129.5 km (50 square miles). The ore at Pedra Azul averages 7% carbon, is larger flaked than the other, and is disserninated in heavily weathered gneissic rock. 

Acres Square miles 0.001563 Bushels (U.S. dry) Cubic meters 0.0.3524... 

Anthropological research with modern hunter-gatherers suggests an ideal type or model for this kind of society. They were nomadic and exhibited low population size and density—on the order of thirty people per thousand square miles. Paramount in maiiitaining this low size and density was an imperative common to all hunter-gatherer women. A nomad woman had to move herself, all that her family owned (which was very little), and her children at a moments notice. Modern hunters and gatherers often have to walk twenty miles a day, so mothers cannot carry more than one small child. Faced with this restriction, women are careful to space their children so that the two or rarely three children they have... 

Burning fossil fuel releases carbon into the atmosphere—more than 6.3 billion tons in 1998 alone. Significant amounts of carbon also come from burning of live wood and deadwood. Such fires are often deliberately set to clear land for crops and pastures. In 1988 the smoke from fires set in the Amazon Basin covered 1,044,000 square miles. By far the most serious implication of this is the significant threat to Earth s ecosystems by global climate change. 

MACC was established in 1967 and encompasses nearly 50,000 square miles from Virginia to New York. MAAC contains the PJM centrally dispatched electric control area, which is the largest such area in North America and the third largest in the world. PJM Interconnection became the first operational independent system operator in the United States on Januai y 1, 1998. 

A much more serious nuclear accident occurred at Chernobyl in the USSR on April 26, 1986, when one of the Chernobyl units experienced a full-core meltdown. The Chernobyl accident has been called the worse disaster of the industrial age. An area comprising more than 60,000 square miles in the Ukraine and Belarus was contaminated, and more than 160,000 people were evacuated. However, wind and water have spread the contamination, and many radiation-related illnesses, birth defects, and miscarriages have been attributed to the Chernobyl disaster. 

The European windtnill diffused rapidly, especially along the Baltic and North Sea coasts. By the fourteenth centui y they had become a major source of power. Eventually, England had as many as 10,000 windmills, with comparable numbers in Holland, France, Germany, and Finland. In some areas of Holland one could find several hundred windmills in a few square miles. 

Each day, tropical oceans absorb the energy equivalent to 250 billion barrels of oil. If less than one-tenth of 1 percent of this energy could be converted into electricity it would supply twenty times the amount of electricity, consumed daily in the United States. Unfortunately, this energy is spread out over 23 million square miles of ocean, providing a large volume of slightly heated water. 

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Square meters Square miles = Square millimeters... 

Oceans occupy 70.8% or 125 million square miles of the surface of the earth. Within or beneath this inner space are foods, fuels, and minerals. Thus interest in the sea is obvious. At least 4/5 of all life on earth exists in saltwater. It is predicted that of the oil and gas demand in future years will come from oil at 2,000 ft. depths operated by manned submarines and marine robots. All the equipment needed to collect and store oil or gas will be installed and operated on the sea floor. Underwater housing and decompression chambers will be required. The sea bottom is also reported to include trillions of tons of copper, nickel, cobalt, iron, and other important minerals. 

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