30 résultats pour "vehicles"

• Rocket.

  the vacuum of space, however, demonstrated that this belief was not true. In fact, rockets produce more thrust in the vacuum of space than on Earth. Air pressure andfriction with the air reduce a rocket’s thrust by about 10 percent on Earth as compared to the rocket’s performance in space. B Thrust and Efficiency Thrust is a measurement of the force of a rocket, or the amount of “push” exerted backward to move a rocket forward. Thrusts vary greatly from rocket to rocket.Engineers measure thrust...

• Rocket - astronomy.

  the vacuum of space, however, demonstrated that this belief was not true. In fact, rockets produce more thrust in the vacuum of space than on Earth. Air pressure andfriction with the air reduce a rocket’s thrust by about 10 percent on Earth as compared to the rocket’s performance in space. B Thrust and Efficiency Thrust is a measurement of the force of a rocket, or the amount of “push” exerted backward to move a rocket forward. Thrusts vary greatly from rocket to rocket.Engineers measure thrust...

• Artificial Satellite - astronomy.

  The first stage of a multistage rocket consists of rocket engines that provide a huge amount of force, or thrust. The first stage lifts the entire launch vehicle—with itsload of fuel, the rocket body, and the satellite—off the launch pad and into the first part of the flight. After its engines use all their fuel, the first stage portion of therocket separates from the rest of the launch vehicle and falls to Earth. The second stage then ignites, providing the energy necessary to lift the satellit...

• Apollo Program - astronomy.

  Moon’s orbit; rendezvousing and docking with the CSM; and finally, setting a course home to Earth. On return to Earth, the spacecraft was slowed by drag from Earth’satmosphere and by parachutes (just before splashdown), before landing in the ocean. The transit time to and from the Moon was approximately three days each way.Depending on the specific mission, the time in lunar orbit ranged from less than one day for Apollo 8 to over six days for the final three missions, and the time on thelunar s...

• Apollo Program - U.

  Moon’s orbit; rendezvousing and docking with the CSM; and finally, setting a course home to Earth. On return to Earth, the spacecraft was slowed by drag from Earth’satmosphere and by parachutes (just before splashdown), before landing in the ocean. The transit time to and from the Moon was approximately three days each way.Depending on the specific mission, the time in lunar orbit ranged from less than one day for Apollo 8 to over six days for the final three missions, and the time on thelunar s...

• Automobile.

  Electric motors have been used to power automobiles since the late 1800s. Electric power supplied by batteries runs the motor, which rotates a driveshaft, the shaftthat transmits engine power to the axles. Commercial electric car models for specialized purposes were available in the 1980s. General Motors Corporation introduced amass-production all-electric car in the mid-1990s. Automobiles that combine two or more types of engines are called hybrids. A typical hybrid is an electric motor with ba...

• Acid Rain.

  the Adirondack Mountains of New York State, a quarter of the lakes and ponds are acidic, and many have lost their brook trout and other fish. In the middleAppalachian Mountains, over 1,300 streams are afflicted. All of Norway’s major rivers have been damaged by acid rain, severely reducing salmon and trout populations. E Plants and Animals The effects of acid rain on wildlife can be far-reaching. If a population of one plant or animal is adversely affected by acid rain, animals that feed on tha...

• Atificiel

  Sustainability 2019,11 , 189 2 of 24Since the 1980s, many research was conducted to minimize the error of prediction through a method dubbed as gradient descent. This method is referred to as a Backpropagation algorithm for the training of the ANNs and it was applied to solve problems in different domains using few hidden layers [ 5,6]. Today, the availability of data has introduced the concept of machine learning as a subcategory to AI. Machine learning implies coding the computers to behave l...

• MIRV MIRV, abréviation de Multiple Independently targetable Reentry Vehicle (« véhicule

• Canadian Forces.

  As the Land Force Command component of the CF, the Canadian army is responsible for land combat and for physically protecting people and land-based resources. Itis the component of the CF most often called on to support international military operations and peacekeeping missions and to maintain order in times of civil unrest. A Organization The 20,900 personnel who comprise the army’s regular force are organized into four geographically based areas. Land Force Atlantic includes the provinces of...

• Police.

  body. In larger agencies, executive officers may be selected through a civil service or merit system, after moving through the ranks from patrol officer to sergeant,lieutenant, captain, and (in still larger agencies) deputy or assistant chief. At the county level, the head of the agency usually holds the title sheriff. The sheriff is almost always elected and has the power to appoint deputies. Sheriffs'departments often provide law enforcement services for unincorporated areas of counties and ar...

• Toys. I INTRODUCTION Toys, objects that serve as playthings for children. Although the

  clay. These readily available elements were also used to make more elaborate toys as human society advanced. Archaeologists have found primitive, handmade toys such as wooden or cloth dolls, clay marbles, and terracotta figures that date back thousands of years. In ancientEgypt, Greece, and Rome, people placed dolls or clay figures in the graves or tombs of children for them to play with in the afterlife. The yo-yo may seem like a 20th-century fad, but it actually dates back at least 2,500 years...

• Delaware - geography.

  D Climate Delaware has generally hot and humid summers and mild winters. D1 Temperature In July, average daytime temperatures are usually in the upper 20°s to lower 30°sC (80°sF) or even higher. But because summer nights tend to be cooler than thedays, July averages are about 24°C (about 75°F). In addition, onshore sea breezes can reduce daytime temperatures along the coast by 3 to 6 Celsius degrees (5 to 10Fahrenheit degrees). January averages range from -1°C (31°F) at Newark, in the north, t...

• Delaware - USA History.

  D Climate Delaware has generally hot and humid summers and mild winters. D1 Temperature In July, average daytime temperatures are usually in the upper 20°s to lower 30°sC (80°sF) or even higher. But because summer nights tend to be cooler than thedays, July averages are about 24°C (about 75°F). In addition, onshore sea breezes can reduce daytime temperatures along the coast by 3 to 6 Celsius degrees (5 to 10Fahrenheit degrees). January averages range from -1°C (31°F) at Newark, in the north, t...

• Space Exploration - astronomy.

  to produce 250,000 newtons (56,000 lb) of thrust. The Germans launched thousands of V-2s carrying explosives against targets in Britain and The Netherlands. Whilethey did not prove to be an effective weapon, V-2s did become the first human-made objects to reach altitudes above 80 km (50 mi)—the height at which outer spaceis considered to begin—before falling back to Earth. The V-2 inaugurated the era of modern rocketry. A2 Early Artificial Satellites During the years following World War II, the...

• Federal Republic of Germany - country.

  B Rivers and Lakes Rivers have played a major role in Germany’s economic development. The Rhine River flows in a northwesterly direction from Switzerland through much of westernGermany and The Netherlands into the North Sea. It is a major European waterway and a pillar of commerce and trade. Its primary German tributaries include theMain, Mosel, Neckar, and Ruhr rivers. The Oder (Odra) River, along the border between Poland and Germany, runs northward and empties into the Baltic; it provides an...

• Space Shuttle - astronomy.

  The two SRBs, with their combined thrust of some 26 million newtons (about 5.8 million lb), provide most of the power for the first two minutes of flight. The SRBs takethe space shuttle to an altitude of 45 km (28 mi) and a speed of 4,973 km/h (3,094 mph) before they separate and fall back into the ocean to be retrieved,refurbished, and prepared for another flight. After the boosters fall away, the three main engines continue to provide thrust. These engines are clustered at the rear end of the...

• Israel (country) - country.

  harbor in the northern part of the country, and Ashdod, an artificial deepwater port to the south, serve as the main seaports on the Mediterranean. The port of Elat onthe Gulf of Aqaba provides Israel’s only access to the Red Sea, making it extremely important to the country’s shipping interests. D Natural Resources Although much of Israel’s desert regions contain poor soils, the northern Negev, the coastal plains, and the interior valleys provide patches of productive soils. Anestimated 18 per...

• Tauchen 1 EINLEITUNG Tauchen, Aufenthalt Luft atmender Organismen oder spezialisierter Geräte unter Wasser.

  Kreislaufgeräten, bei denen das ausgeatmete Gas in einer Atemkalkpatrone von Kohlendioxid befreit und wieder dem Atemkreislauf zugeführt wird. Die Verwendung reinenSauerstoffs ermöglicht blasenfreies Tauchen bis durchschnittlich sieben Meter Tiefe, andere Gemische wie Nitrox oder Heliox zirkulieren vor allem in so genannten halbgeschlossenen Kreislaufgeräten. Die Motivation für das Gerätetauchen liegt heute neben der sportlichen Freizeitgestaltung in verschiedenen beruflichen Arbeitsfeldern begr...

• Dogsledding.

  Mushers are caretakers, but also coaches. Top mushers have large kennels, and their preparation for competition begins by buying and breeding race-specific dogs.They train their dogs, decide which to run on certain days, and make adjustments during races by switching and dropping dogs. Serious competitors run their dogsyear-round, using carts and all-terrain vehicles when there is not enough snow on the ground. During races they decide their strategy, choosing when to rest and whento push ahead....

• Lima (Peru) - geography.

  home to a wide range of museums, many focusing on Peru’s indigenous heritage. These include the National Museum of Anthropology and Archaeology, the GoldMuseum of Peru, the Museum of the Central Reserve Bank, and the Rafael Larco Herrera Museum, which specializes in pre-Hispanic ceramics. Art and history museumsare also found in metropolitan Lima, including the National Museum of the Republic, the Museum of Peruvian Culture, and the Museum of the Inquisition, in the buildingwhere colonial Cathol...

• Wireless Communications.

  were large, heavy units. After the invention of the transistor in 1948, radios shrank in size to small handheld radio transceivers. Public two-way radios with severalfrequency options are widely available as well. Usually limited in range to a few miles, these units are great aids for such mobile professionals as construction workers,film crews, event planners, and security personnel. Simpler two-way radios, called walkie-talkies, have been popular children’s toys for years. Most walkie-talkiesb...

• Collectibles and Collecting.

  common blond and thus commands a higher price. If there are different variations to a collectible, the least common one is usually worth more. Often there areinteresting stories behind rarities, such as the highly sought-after 1909 Honus Wagner baseball card. At that time tobacco companies manufactured and distributedbaseball cards, and when the antitobacco Wagner complained, his card was pulled from production. Very few copies in good condition have ever been found. C Age Age is often an indic...

• Kansas City (Missouri) - geography.

  Major institutions of higher education in Kansas City are a branch (established in 1929) of the University of Missouri, Avila College (1916), Rockhurst College (1910),DeVry Institute of Technology (Missouri) (1931), and the Kansas City Art Institute (1885). Schools in neighboring suburbs include Park University (1875), in Parkville,and William Jewell College (1849), in Liberty. Baptist, Nazarene, and Methodist theological schools are also located in the area. Midwest Research Institute, one of t...

• Technology.

  loose soil in this region, known as the Fertile Crescent, was easily scratched for planting, and an abundance of trees was available for firewood. By 5000 BC, farming communities were established in areas known today as Syria, Turkey, Lebanon, Israel, Jordan, Greece, and the islands of Crete and Cyprus. Agricultural societies in these places constructed stone buildings, used the sickle to harvest grain, developed a primitive plowstick, and advanced their skills inmetalworking. Trade in flint al...

• Madrid - geography.

  stores and offices on the first one or two levels. While many people rent their apartments, most own them and participate in cooperatives that maintain the building.Because living spaces are small by American standards, madrileños do most of their socializing in the streets, bars, restaurants, and parks of their neighborhoods. Onlya few very wealthy areas north of the city have single family houses with gardens and yards similar to those in American suburbs. Many of the newest neighborhoodsare c...

• Global Warming.

  some of the warming influence of increasing greenhouse gases. A1 Carbon Dioxide Carbon dioxide is the second most abundant greenhouse gas, after water vapor. Carbon dioxide constantly circulates in the environment through a variety of naturalprocesses known as the carbon cycle. It is released into the atmosphere from natural processes such as eruptions of volcanoes; the respiration of animals, whichbreathe in oxygen and exhale carbon dioxide; and the burning or decay of plants and other organic...

• Automobile Racing.

  beginning in 1906 at Le Mans it came to refer to the principal F1 auto race in a given nation, except in the United States, where the term continues to be used lessdiscriminately. After the end of World War I in 1918, when automobile racing blossomed internationally, a series of GP races in several nations became reserved for F1competition, and an annual GP calendar was developed consisting of national races, such as the French Grand Prix and the British Grand Prix. An annual award calledthe Wor...

• Jazz I INTRODUCTION Joshua Redman Saxophonist Joshua Redman, a graduate of Harvard University, became a fast-rising star in jazz in the 1990s.

  performed a highly produced, jazz-inspired form of blues that was popular in traveling minstrel shows and vaudeville. Thisexample is from the song “St. Louis Blues,” written by American composer and trumpet player W. C. Handy in 1914 andrecorded by Smith in 1925."St. Louis Blues" performed by Bessie Smith, from The Riverside History of Classic Jazz (Cat.# Riverside RB-005) Riverside Records under master license to Fantasy, Inc. All rightsreserved./Frank DriggsCollection/Archive Photos Jazz is ro...

• Greece - country.

  minerals, such as chromium, copper, uranium, and magnesium, are relatively small. Greece’s small petroleum deposits, located under the Aegean Sea near the island ofThásos, are rapidly being depleted. There are no significant reserves of natural gas. Greece’s forests, probably abundant in ancient times, have been significantly depleted. Subsequent soil erosion has made reforestation efforts difficult. Although muchof Greece’s soil is rocky and dry, the country’s mountains are interspersed with sm...