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Search results 25321 - 25330 of 30573 matching essays
- 25321: Uranium
- Uranium Uranium was discovered in the 1700's in the coal mines of bohemia and Jachlovikna. Uranium's atomic number is 92, its Symbol is U and the atomic mass of uranium is 238.0289. Miners called it Pechblende meaning, Pechblende, from the German words pech, which means either pitch or bad luck, and blende, meaning mineral Uranium's first full analysis was done on 1789 by Martin Klaproth, a self-taught well educated german chemist. Klaproth, having extracted from pitchblende what he called 'a strange kind of half metal' (he had only ...
- 25322: The Future of NASA
- The Future of NASA One hundred years from now, NASA's space program will not be so far advanced that people will be able to beam around the Universe or travel through time. However, unless something goes terribly wrong with the world, it is expected to ... hands-on perspective. Because of the overpopulated Earth, scientists may even be considering ways to alter life on Mars, so that people would be able to live there some day. Some products developed in NASA's space program that we now incorporate in our daily lives include the vacuum cleaner, pacemaker, pens that can write upside-down, and the zero-gravity training system. The vacuum cleaner was originally a great tool ... in outer space. It is now a very helpful tool for cleaning our homes. The pacemaker is a form of life-support on spacecrafts, helping astronomers' hearts pump while they are outside of the Earth's atmosphere. It is used, on Earth, for those who's hearts have problems with pumping blood. Pens that write upside-down are used in space, where there is no gravity and writing with pens ...
- 25323: The Serious Problem of Acid Rain
- ... This is why many lakes in the Muskoka, Haliburton, Algonquin, Parry Sound and Manitoulin districts could lose their fisheries if sulfur emissions are not reduced substantially. ACIDITY The mean average of pH rainfall in Ontario's Muskoka-Haliburton lake country ranges between 3.95 and 4.38 about 40 times more acidic than normal rainfall, while storms in Pennsylvania have rainfall pH at 2.8 it almost has the same rating ... provincial authorities calculate that Ontario stands to lose the fish in 48,500 more lakes within the next twenty years if acid rain continues at the present rate. Ontario is not alone, on Nova Scotia's eastern most shores, almost every river flowing to the Atlantic Ocean is poisoned with acid. Further threatening a $2 million a year fishing industry. ENVIRONMENTAL DEATH Acid rain is killing more than lakes. It can ... damages plant and animal life in lakes and streams. Lakes become "dead," unable to support life. All the fish in 140 lakes in Minnesota have been killed, and the salmon and trout populations of Norway's major rivers have been severely reduced because of the increased acidity of the water. Short-term increases in acid levels kill lots of fish, but the greatest threat is from long-term increases, which ...
- 25324: Chivalrous Code
- ... and made the knighting ceremony a religious occasion with a church vigil and purifying bath. Books on the subject soon began to appear. Many forms of chivalrous code can be found today, from The Cowboy’s Code to the Rules of Courtly Love. These codes are stated with the hope that people will try and follow them to some degree; yet only the perfect could adhere to them all. Considering the ... upheld this particular code with valor and bravery. For my second example, I looked to Sir Gawain. The story of the Green Knight is seeped with instances of chivalry, and honorable men. “Always keep one’s word of honor,” was an obvious code for this particular story. Not only did Sir Gawain show respect for the codes of chivalry by serving his king, exhibiting courage, and fighting with honor; he kept ... if nothing else, must be praised for his valiant efforts to follow the laws of the great knights. After encountering a man beating a half naked youth, he informs him that “it is a caitiff’s deed to attack one who cannot defend himself.” This directly follows the code that one must “never use a weapon on an opponent not equal to the attack.” Don Quixote also attempts to ‘protect ...
- 25325: Mescaline
- ... it effects the brain by interfering with the normal functions of such neurotransmitters as serotonin. These effects are found mostly in the brain stem, where the neurons are particularly effected by hallucinogens. Duration of it's effects last about twelve hours. Mescaline is commonly found in cacti such as Peyote (lophophora williamsii), San Pedro (trichocerus pachanoi), and Peruvian Torch (trichocerus peruvianus). There are also synthetic forms of Mescaline referred to as ... 100-200mg) can give the user feelings of giddiness or anxiety, and a moderate dose of Mescaline (200-300mg) begins to impair the senses. Strong doses (300-500mg) will induce hallucinations and effect the user's perceptions of color, time, and space. Heavy does of Mescaline (500-700mg) and frequent use of mescaline will cause symptoms of schizophrenia, psychotic episodes, and may be fatal. At any point the user may also feel the effects of nausea, dizziness, depressed or increased breathing, as well as increased heart rate and blood pressure. Long term effects also include chromosomal damage and possible birth defects. Possibly due to it's euphoric qualities, Mescaline is used in Native American and Mexican Indian rituals and is believed to hold great spiritual power. Mescaline also provides feelings of a union with nature, due to a dissolution of ...
- 25326: Magnesium
- ... kJ.kg -1 Flame temperature ~2800ºC Heat of fusion 368 kJ.kg-1 Heat of vaporisation 5272 kJ.kg-1 Specific heat 1025 J.K -1.kg at 20ºC Vapour pressure 20 Pa at 527ºC(s) 360 Pa at 650ºC (1) 1400 Pa at 727ºC Valence states Mg2+ Viscosity 1.25 cp at 650ºC (1) The magnesium element has the atomic number of 12 and atomic weight of 24.3050. It's symbol is Mg. The group number that mg is in is group 2a. It's electronic configuration of [Ne].3 s2. Physical data Standard state: solid at 298 K Colour: silvery white Density of solid at ambient temperature/kg m-3: 1738 Molar volume/cm3: 14.00 Table on ...
- 25327: The Aftermath of Hurricane Mitch
- The Aftermath of Hurricane Mitch Americans eager to help. Just days after Hurricane Mitch devastated Honduras and its Central American neighbors, U.S. citizens began calling the Honduran Consulate in Washington, D.C., asking how to adopt children orphaned by the storm. Beyond the confines of the airport, life becomes even more chaotic. Roads are choked with automobiles ... hardening in the midday sun. Mud is everywhere. Several feet of it fill city streets, the first and even second floors of buildings, automobiles and anything else that may have fallen victim to the hurricane's epic floodwaters. Workers hack and chip at the mud with shovels and pickaxes, and an endless procession of shopowners scurry between their gutted businesses and the river in a desperate attempt to wash and salvage their goods. A muddy valley runs past the Central Prison, where some of the incarcerated swam to freedom as Mitch's floodwaters rose and propelled them over the walls. Hundreds of homes, streets, and businesses were washed away, and those that remained standing found themselves anchored beneath several feet of mud and debris. In some ...
- 25328: David Koresh And The Davidians
- ... Bureau of Alcohol, Tobacco, and Firearms (ATF) decided to search the complex for illegal weapons. The tragedy began with a military style raid on February 28, complete with helicopter gunships firing down upon the women's and children's quarters. Then followed a long siege. On April 19, the US government sent tanks to gas the building where the people lived. The government said they decided to gas the Davidians because they were concerned ... no definitive answer, like most historical events; Waco can be view from a variety of perspectives. But in my perspective, I think that what happened in Waco was one of many tragedies that the U.S. had been throw. Like many others this is one that many people could talk about and never agree on really what happened on that day. One of the main things that affected what happened ...
- 25329: Tin
- Tin Tin's discoverer is unknown but one thing is known. Tin has been used and discovered by the ancients. Tin was an accidental discovery. Tin has been around for many years. Proof is in the fact that ... but almost no tin is found in America, although some tin has been found in Alaska and California. Tins basic information. Tin has an atomic number fifty on the periodical table of the elements. Tin's atomic symbol is Sn. Tin's atomic weight is 119 amu (118.69 amu). Tin's electronic configuration is 2-8-18-18-4. Tin is in Group 14. Tin has a gray color unless heated then it turns white. ...
- 25330: Silicon
- ... devices at higher temperatures than germanium. Now I will give you some brief history of the evolution of electronics which will help you understand more about semiconductors and the silicon chip. In the early 1900's before integrated circuits and silicon chips were invented, computers and radios were made with vacuum tubes. The vacuum tube was invented in 1906 by Dr.Lee DeForest. Throughout the first half of the 20th century ... of power, took time to warm up, got very hot, and eventually burned out. The first digital computer contained 18,000 vacuum tubes, weighed 50 tins, and required 140 kilowatts of power. By the 1930's, researchers at the Bell Telephone Laboratories were looking for a replacement for the vacuum tube. They began studying the electrical properties of semiconductors which are non-metallic substances, such as silicon, that are neither conductors ... was much smaller than the vacuum tube, did not get very hot, and did not require a headed filament that would eventually burn out. Finally in 1958, integrated circuits were invented. By the mid 1950's, the first commercial transistors were being shipped. However research continued. The scientist began to think that if one transistor could be built within one solid piece of semiconductor material, why not multiple transistors or ...
Search results 25321 - 25330 of 30573 matching essays
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