Questões de Concurso

NASA’s Nuclear Frontier: The Plum Brook Reactor Facility

    There are three main types of nuclear reactors: power, research, and test. Research and test reactors as scientific tools are more common than most people realize. While power reactors frequently appear in newspaper headlines and are conspicuous because of their size and power, research reactors can be quietly tucked away, even in the midst of a college campus. Power reactors generate heat, which can easily be converted to other useable forms of energy, such as electricity. Research reactors operate at very low thermal power levels – so low, in fact, that they do not even require any type of forced cooling. They are used to measure nuclear parameters and other characteristics, which can then be used to build other reactors or to design experiments for test reactors. Test reactors are more powerful than research reactors and are able to produce much more intense radiation fields. Though they are still much less powerful than the power reactors, they generate enough heat to require a closed-loop forced-circulation coolant system. This system will remove the heat from the reactor by transferring it to a secondary cooling system, which releases it into the atmosphere through cooling towers.

NASA’s Nuclear Frontier: The Plum Brook Reactor Facility. Pages 36 to 40. 

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The birth of a nation

     The most memorable writing in eighteenth-century America was done by the founding fathers, the men who led the American Revolution of 1775-1783 and wrote the constitution of 1989. But none of them were writers of fiction. Rather, they were practical philosophers, and their most typical product was the political pamphlet. They shared the European Enlightenment belief that human reason could understand both nature and man. Unlike the Puritans – who saw man as a sinful failure – the Enlightenment men were sure man could improve himself. They wanted to create a happy society based on justice and freedom.

     The writings of Benjamin Franklin (1706 -1790) show the Enlightenment spirit in America at its best and most optimistic. His style is quite modern and, even today, his works are a joy to read. At the same time, there’s something “anti-literary” about Franklin. He had no liking for poetry and felt that writing should always have a practical purpose.

     Almanacs, containing much useful information for farmers and sailors (about the next year’s weather, sea tides, etc.), were a popular form of practical literature. Together with the Bible and the newspaper, they were the most-widely read and often the only reading matter in most Colonial households. Franklin made his Almanac interesting by creating the character “Little Richard”. Each new edition continued a simple but realist story about Richard, his wife and family. He also included many “sayings” about saving money and working hard. Some of those are known to most Americans today:

     Lost time is never found again.

     God helps those who help themselves.

     In 1757 Franklin collected together the best of his sayings and published The Way to Wealth. This little book became one of the best-sellers of the Western World and was translated into many languages.

(Peter High. Outline of American Literature . Essex, Longman. 1996. Adaptado)