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== '''[[Acid rain]]''' ==
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'''Acid rain''' is a popular term for the atmospheric deposition of acidified [[rain]], [[snow]], sleet, hail and [[particulates]], as well as acidified [[fog]] and [[cloud]] [[water]]. The increased [[pH|acidity]] of these depositions, primarily from [[Sulfuric acid|sulfuric]] and [[nitric acid]]s, is generated as a by-product of the [[combustion]] of fuels,<ref>'''Note:''' Sulfuric acid is formed from the sulfur dioxide resulting from combustion of sulfur-containing fuels. Nitric acid is formed from the [[nitrogen oxides]] resulting from the high temperature partial conversion of the [[nitrogen]] contained in the combustion air.</ref> especially in [[fossil fuel]] [[power plant]]s. The heating of homes, electricity production, and driving vehicles all rely primarily on fossil fuel [[Energy (science)|energy]]. When fossil fuels are burned, [[acid]]-forming [[nitrogen oxides]] and [[sulfur oxides]] are released to the [[atmosphere]]. These [[chemical compound]]s are transformed in the atmosphere, often traveling thousands of [[kilometer]]s from their original source, and then fall out on land and water surfaces as acid rain. As a result, air [[pollutant]]s from power plants in the states of  [[New Jersey]] or [[Michigan]] can impact pristine forests or lakes in undeveloped parts of the states of [[New Hampshire]] or [[Maine]].<ref name=eoearth>The primary source for this article was [http://www.eoearth.org/article/Acid_rain?topic=49506 Acid Rain] August 7, 2010 (last revised  October 19, 2010), Gene Likens (Lead author), Wayne Davis, Lori Zaikowski and Stephen C. Nodvin. (Published on the website of the [[Encyclopedia of Earth]])</ref>
==Footnotes==
 
Acid rain in [[North America]] was discovered in 1963 in rain at  the [[Hubbard Brook Experimental Forest]] (HBEF)<ref>'''Note:''' Site of the Hubbard Brook Ecosystem Study in the [[White Mountains]] of [[New Hampshire]]</ref> that was some 100 times more acidic than unpolluted rain. Innovations for reducing fossil fuel combustion [[Air pollution emissions|emissions]], such as scrubbers upstream of the tall [[flue gas stack]]s on power plants and other industrial facilities, [[catalytic converter]]s on automobiles, and use of low-[[sulfur]] [[coal]], have been employed to reduce emissions of [[sulfur dioxide]] (SO<sub>2</sub>) and nitrogen oxides (NOx).
 
''Note:'' While the examples in this article describe the North American situation, the nature and effects of acid rain are similar all over the world.
 
 
''[[Acid rain|.... (read more)]]''
 
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Latest revision as of 10:19, 11 September 2020

1901 photograph of a stentor (announcer) at the Budapest Telefon Hirmondó.

Telephone newspaper is a general term for the telephone-based news and entertainment services which were introduced beginning in the 1890s, and primarily located in large European cities. These systems were the first example of electronic broadcasting, and offered a wide variety of programming, however, only a relative few were ever established. Although these systems predated the invention of radio, they were supplanted by radio broadcasting stations beginning in the 1920s, primarily because radio signals were able to cover much wider areas with higher quality audio.

History

After the electric telephone was introduced in the mid-1870s, it was mainly used for personal communication. But the idea of distributing entertainment and news appeared soon thereafter, and many early demonstrations included the transmission of musical concerts. In one particularly advanced example, Clément Ader, at the 1881 Paris Electrical Exhibition, prepared a listening room where participants could hear, in stereo, performances from the Paris Grand Opera. Also, in 1888, Edward Bellamy's influential novel Looking Backward: 2000-1887 foresaw the establishment of entertainment transmitted by telephone lines to individual homes.

The scattered demonstrations were eventually followed by the establishment of more organized services, which were generally called Telephone Newspapers, although all of these systems also included entertainment programming. However, the technical capabilities of the time meant that there were limited means for amplifying and transmitting telephone signals over long distances, so listeners had to wear headphones to receive the programs, and service areas were generally limited to a single city. While some of the systems, including the Telefon Hirmondó, built their own one-way transmission lines, others, including the Electrophone, used standard commercial telephone lines, which allowed subscribers to talk to operators in order to select programming. The Telephone Newspapers drew upon a mixture of outside sources for their programs, including local live theaters and church services, whose programs were picked up by special telephone lines, and then retransmitted to the subscribers. Other programs were transmitted directly from the system's own studios. In later years, retransmitted radio programs were added.

During this era telephones were expensive luxury items, so the subscribers tended to be the wealthy elite of society. Financing was normally done by charging fees, including monthly subscriptions for home users, and, in locations such as hotel lobbies, through the use of coin-operated receivers, which provided short periods of listening for a set payment. Some systems also accepted paid advertising.

Footnotes