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Hangar One (Mountain View, California)
Hangar One is one of the world's largest freestanding structures, covering at Moffett Field near Mountain View, California in the San Francisco Bay Area. The massive hangar has long been one of the most recognizable landmarks of California's Silicon Valley. It was built in the 1930s as a naval airship hangar for the USS ''Macon'' and is now part of the NASA Ames Research Center. Design and construction Designed by German air ship and structural engineer Dr. Karl Arnstein, Vice President and Director of Engineering for the Goodyear Zeppelin Corporation of Akron, Ohio, in collaboration with Wilbur Watson Associates Architects and Engineers of Cleveland, Ohio, Hangar One is constructed on a network of steel girders sheathed with galvanized steel. It rests firmly upon a reinforced pad anchored to concrete pilings. The floor covers 8 acres and can accommodate six (360 feet x 160 feet) American football fields. The airship hangar measures long and wide. The building has an ae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Santa Clara County, California
Santa Clara County, officially the County of Santa Clara, is the sixth-most populous county in the U.S. state of California, with a population of 1,936,259, as of the 2020 United States Census, 2020 census. Santa Clara County and neighboring San Benito County, California, San Benito County together form the U.S. Census Bureau's San Jose-Sunnyvale-Santa Clara metropolitan statistical area, which is part of the larger San Jose-San Francisco-Oakland, California, Oakland combined statistical area. Santa Clara is the most populous county in the San Francisco Bay Area and in Northern California. The county seat and largest city is San Jose, California, San Jose, the List of United States cities by population, 10th-most populous city in the United States, List of cities and towns in California, California's third-most populous city and the List of cities and towns in the San Francisco Bay Area, most populous city in the San Francisco Bay Area. Home to Silicon Valley, Santa Clara County ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reinforced Concrete
Reinforced concrete (RC), also called reinforced cement concrete (RCC) and ferroconcrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ductility. The reinforcement is usually, though not necessarily, steel bars ( rebar) and is usually embedded passively in the concrete before the concrete sets. However, post-tensioning is also employed as a technique to reinforce the concrete. In terms of volume used annually, it is one of the most common engineering materials. In corrosion engineering terms, when designed correctly, the alkalinity of the concrete protects the steel rebar from corrosion. Description Reinforcing schemes are generally designed to resist tensile stresses in particular regions of the concrete that might cause unacceptable cracking and/or structural failure. Modern reinforced concrete can contain varied reinforcing materials made of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orly Air Base
Orly Air Base was a United States Air Force Facility during the early part of the Cold War, located at Aéroport de Paris-Orly, south of Paris, France. The American Air Base was located on the north side of the airport, in an area east of the current-day Val-de-Marne/Essonne. The facility was first developed as a military airfield by the Air Service, American Expeditionary Forces (AEF) during World War I. With the end of the war, in 1920 it was eventually developed into a civil airport. After the 1940 Battle of France, the occupying German Luftwaffe seized the facility and used it as a military airfield. In 1944, the Germans were driven out and it subsequently became an Advanced Landing Ground (ALG) designated A-47 for the United States Army Air Forces Ninth Air Force. Rebuilt after the war as a joint civil/military airfield, the primary use of the base was to support Supreme Headquarters Allied Powers Europe (SHAPE) at Rocquencourt. Secondary functions were as a personnel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USS Akron (ZRS-4)
USS ''Akron'' (ZRS-4) was a helium-filled rigid airship of the U.S. Navy, the lead ship of her class, which operated between September 1931 and April 1933. It was the world's first purpose-built flying aircraft carrier, carrying F9C Sparrowhawk fighter planes, which could be launched and recovered while it was in flight. With an overall length of , ''Akron'' and her sister ship were among the largest flying objects ever built. Although LZ 129 ''Hindenburg'' and LZ 130 '' Graf Zeppelin II'' were some longer and slightly more voluminous, the two German airships were filled with hydrogen, and so the two US Navy craft still hold the world record for the largest helium-filled airships. ''Akron'' was destroyed in a thunderstorm off the coast of New Jersey on the morning of 4 April 1933, killing 73 of the 76 crewmen and passengers. The accident involved the greatest loss of life in any airship crash. Technical description The airship's skeleton was built of the new lightw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goodyear Airdock
The Goodyear Airdock is a construction and storage airship hangar in Akron, Ohio. At its completion in 1929, it was the largest building in the world without interior supports. Description The building has a unique shape which has been described as "half a silkworm's cocoon, cut in half the long way." It is 1,175 feet (358.14 m) long, 325 feet (99.06 m) wide, and 211 feet (64.31 m) high, supported by 13 steel arches. There is 364,000 square feet (34 000 m²) of unobstructed floor space, or an area larger than 8 football fields side-by-side. The airdock has a volume of 55 million cubic feet (or about 1.5 million cubic meters). A control tower and radio aerial sit at its northeast end. At each end of the building are two huge semi-spherical doors that each weigh 600 tons (544 000 kg). At the top, the doors are fastened by hollow forged pins 17 inches (43 cm) in diameter and six feet (1.83 m) long. The doors roll on 40 wheels along specially-designed curved railroad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airship
An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In early dirigibles, the lifting gas used was hydrogen, due to its high lifting capacity and ready availability. Helium gas has almost the same lifting capacity and is not flammable, unlike hydrogen, but is rare and relatively expensive. Significant amounts were first discovered in the United States and for a while helium was only available for airships in that country. Most airships built since the 1960s have used helium, though some have used hot air.A few airships after World War II used hydrogen. The first British airship to use helium was the ''Chitty Bang Bang'' of 1967. The envelope of an airship may form the gasbag, or it may contain a number of gas-filled cells. An airship also has engines, crew, and optionally also payload accommodation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Gauge
A standard-gauge railway is a railway with a track gauge of . The standard gauge is also called Stephenson gauge (after George Stephenson), International gauge, UIC gauge, uniform gauge, normal gauge and European gauge in Europe, and SGR in East Africa. It is the most widely used track gauge around the world, with approximately 55% of the lines in the world using it. All high-speed rail lines use standard gauge except those in Russia, Finland, and Uzbekistan. The distance between the inside edges of the rails is defined to be 1435 mm except in the United States and on some heritage British lines, where it is defined in U.S. customary/Imperial units as exactly "four feet eight and one half inches" which is equivalent to 1435.1mm. History As railways developed and expanded, one of the key issues was the track gauge (the distance, or width, between the inner sides of the rails) to be used. Different railways used different gauges, and where rails of different gauge met – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Park Service
The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational properties with various title designations. The U.S. Congress created the agency on August 25, 1916, through the National Park Service Organic Act. It is headquartered in Washington, D.C., within the main headquarters of the Department of the Interior. The NPS employs approximately 20,000 people in 423 individual units covering over 85 million acres in all 50 states, the District of Columbia, and US territories. As of 2019, they had more than 279,000 volunteers. The agency is charged with a dual role of preserving the ecological and historical integrity of the places entrusted to its management while also making them available and accessible for public use and enjoyment. History Yellowstone National Park was created as the first national par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbulence
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between those layers. Turbulence is commonly observed in everyday phenomena such as surf, fast flowing rivers, billowing storm clouds, or smoke from a chimney, and most fluid flows occurring in nature or created in engineering applications are turbulent. Turbulence is caused by excessive kinetic energy in parts of a fluid flow, which overcomes the damping effect of the fluid's viscosity. For this reason turbulence is commonly realized in low viscosity fluids. In general terms, in turbulent flow, unsteady vortices appear of many sizes which interact with each other, consequently drag due to friction effects increases. This increases the energy needed to pump fluid through a pipe. The onset of turbulence can be predicted by the dimensionless Rey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalve Shell
A bivalve shell is part of the body, the exoskeleton or shell, of a bivalve mollusk. In life, the shell of this class of mollusks is composed of two hinged parts or ''valves''. Bivalves are very common in essentially all aquatic locales, including saltwater, brackish water, and freshwater. The shells of bivalves commonly wash up on beaches (often as separate valves) and along the edges of lakes, rivers, and streams. Bivalves by definition possess two shells or ''valves'', a "right valve" and a "left valve", that are joined by a ligament. The two valves usually articulate with one another using structures known as "teeth" which are situated along the hinge line. In many bivalve shells, the two valves are symmetrical along the hinge line—when truly symmetrical, such an animal is said to be ''equivalved''; if the valves vary from each other in size or shape, ''inequivalved''. If symmetrical front-to-back, the valves are said to be ''equilateral'', and are otherwise considered ''in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catenary
In physics and geometry, a catenary (, ) is the curve that an idealized hanging chain or cable assumes under its own weight when supported only at its ends in a uniform gravitational field. The catenary curve has a U-like shape, superficially similar in appearance to a parabola, which it is not. The curve appears in the design of certain types of arches and as a cross section of the catenoid—the shape assumed by a soap film bounded by two parallel circular rings. The catenary is also called the alysoid, chainette,MathWorld or, particularly in the materials sciences, funicular. Rope statics describes catenaries in a classic statics problem involving a hanging rope. Mathematically, the catenary curve is the graph of the hyperbolic cosine function. The surface of revolution of the catenary curve, the catenoid, is a minimal surface, specifically a minimal surface of revolution. A hanging chain will assume a shape of least potential energy which is a catenary. Galileo Galil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
