An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. As the wavelength of an electron can be up to 100,000 times shorter than that of visible light photons, electron microscopes have a higher resolving power than light microscopes and can reveal the structure of smaller objects. A scanning transmission electron microscope has achieved better than 50 pm resolution in annular dark-field imaging mode and magnifications of up to about 10,000,000x whereas most light microscopes are limited by diffraction to about 200 nm resolution and useful magnifications below 2000x. Electron microscopes have electron optical lens systems that are analogous to the glass lenses of an optical light microscope. Electron microscopes are used to investigate the ultrastructure of a wide range of biological and inorganic specimens including microorganisms, large molecules, biopsy samples and crystals. Industrially, electron microscopes are used for quality control and failure analysis.
Modern electron microscopes produce electron micrographs using specialized digital cameras and frame grabbers to capture the images. In 1926 Hans Busch developed the electromagnetic lens. According to Dennis Gabor, the physicist Leó Szilárd tried in 1928 to convince him to build an electron microscope, for which he had filed a patent; the first prototype electron microscope, capable of four-hundred-power magnification, was developed in 1931 by the physicist Ernst Ruska and the electrical engineer Max Knoll. The apparatus was the first practical demonstration of the principles of electron microscopy. In May of the same year, Reinhold Rudenberg, the scientific director of Siemens-Schuckertwerke, obtained a patent for an electron microscope. In 1932, Ernst Lubcke of Siemens & Halske built and obtained images from a prototype electron microscope, applying the concepts described in Rudenberg's patent. In the following year, 1933, Ruska built the first electron microscope that exceeded the resolution attainable with an optical microscope.
Four years in 1937, Siemens financed the work of Ernst Ruska and Bodo von Borries, employed Helmut Ruska, Ernst's brother, to develop applications for the microscope with biological specimens. In 1937, Manfred von Ardenne pioneered the scanning electron microscope. Siemens produced the first commercial electron microscope in 1938; the first North American electron microscope was constructed in 1938, at the University of Toronto, by Eli Franklin Burton and students Cecil Hall, James Hillier, Albert Prebus. Siemens produced a transmission electron microscope in 1939. Although current transmission electron microscopes are capable of two million-power magnification, as scientific instruments, they remain based upon Ruska’s prototype; the original form of the electron microscope, the transmission electron microscope, uses a high voltage electron beam to illuminate the specimen and create an image. The electron beam is produced by an electron gun fitted with a tungsten filament cathode as the electron source.
The electron beam is accelerated by an anode at +100 keV with respect to the cathode, focused by electrostatic and electromagnetic lenses, transmitted through the specimen, in part transparent to electrons and in part scatters them out of the beam. When it emerges from the specimen, the electron beam carries information about the structure of the specimen, magnified by the objective lens system of the microscope; the spatial variation in this information may be viewed by projecting the magnified electron image onto a fluorescent viewing screen coated with a phosphor or scintillator material such as zinc sulfide. Alternatively, the image can be photographically recorded by exposing a photographic film or plate directly to the electron beam, or a high-resolution phosphor may be coupled by means of a lens optical system or a fibre optic light-guide to the sensor of a digital camera; the image detected by the digital camera may be displayed on a computer. The resolution of TEMs is limited by spherical aberration, but a new generation of hardware correctors can reduce spherical aberration to increase the resolution in high-resolution transmission electron microscopy to below 0.5 angstrom, enabling magnifications above 50 million times.
The ability of HRTEM to determine the positions of atoms within materials is useful for nano-technologies research and development. Transmission electron microscopes are used in electron diffraction mode; the advantages of electron diffraction over X-ray crystallography are that the specimen need not be a single crystal or a polycrystalline powder, that the Fourier transform reconstruction of the object's magnified structure occurs physically and thus avoids the need for solving the phase problem faced by the X-ray crystallographers after obtaining their X-ray diffraction patterns. One major disadvantage of the transmission electron microscope is the need for thin sections of the specimens about 100 nanometers. Creating these thin sections for biological and materials specimens is technically challenging. Semiconductor thin sections can be made using a focused ion beam. Biological tissue specimens are chemically fixed and embedded in a polymer resin to stabilize them sufficiently to allow ultrathin sectioning.
Sections of biological specimens, organic polymers, similar materials may require staining with heavy atom labels in order to achieve the required image contrast. One application of TEM is serial-section electron microscopy, for example in analyzing the connectivity in volumetric samples of brain tissue by imaging many thin sections in sequence; the SEM produces imag
A submersible is a small watercraft designed to operate underwater. The term submersible is used to differentiate from other underwater vessels known as submarines, in that a submarine is a autonomous craft, capable of renewing its own power and breathing air, whereas a submersible is supported by a surface vessel, shore team or sometimes a larger submarine. In common usage by the general public, the word submarine may be used to describe a craft, by the technical definition a submersible. There are many types of submersibles, including both crewed and uncrewed craft, otherwise known as remotely operated vehicles or ROVs. Submersibles have many uses worldwide, such as oceanography, underwater archaeology, ocean exploration, equipment maintenance and recovery, underwater videography; the first underwater vessel was designed and built by American inventor David Bushnell in 1775 as a means to attach explosive charges to enemy ships during the American Revolutionary War. The device, dubbed Bushnell's Turtle, was an oval-shaped vessel of brass.
It had tanks that were filled with water to make it dive and emptied with the help of a hand pump to make it return to the surface. The operator used two hand-cranked propellers to laterally under the water; the vehicle had small glass windows on top and luminescent wood affixed to its instruments so that they could be read in the dark. Bushnell's Turtle was first set into action on September 7, 1776 at New York Harbor to attack the British flagship HMS Eagle. Sergeant Ezra Lee operated the vehicle at that time. Lee brought the Turtle against the underside of Eagle's hull but failed to attach the charge because of the strong water currents. Apart from size, the main technical difference between a "submersible" and a "submarine" is that submersibles are not autonomous and may rely on a support facility or vessel for replenishment of power and breathing gases. Submersibles have shorter range, operate underwater, as most have little function at the surface; some submersibles operate on remaining connected to a tender.
Submersibles have been able to dive to over 10 km below the surface. Submersibles may be small, hold only a small crew, have no living facilities. A submersible has dexterous mobility, provided by propeller screws or pump-jets. There are five basic technologies used in the design of submersibles. Single atmosphere submersibles have a pressurized hull and the occupants are at standard atmospheric pressure; this requires the hull to be capable of withstanding the high pressure from the water outside, many times greater than the internal pressure. Another technology called ambient pressure maintains the same pressure both inside and outside the vessel; this reduces the pressure. A third technology is the "wet sub", which refers to a vehicle that may or may not be enclosed, but in either case water floods the interior so SCUBA equipment is used to facilitate breathing. In both single atmosphere and ambient pressure subs, there is no need to use SCUBA equipment and occupants can breathe without wearing any equipment.
Some submersibles have been able to dive to great depths. The Bathyscaphe Trieste was the first to reach the deepest part of the ocean, nearly 11 km below the surface, at the bottom of the Mariana Trench in 1960. China, with its Jiaolong project in 2002, was the fifth country to send a man 3,500 meters below sea level, following the US, France and Japan. On June 22, 2012, the Jiaolong submersible set a deep-diving record when the three-person sub descended 22,844 feet into the Pacific Ocean. Among the most well-known and longest-in-operation submersibles is the deep-submergence research vessel DSV Alvin, which takes 3 people to depths of up to 4,500 metres. Alvin is owned by the United States Navy and operated by WHOI, as of 2011 had made over 4,400 dives. James Cameron made a record-setting, manned submersible dive to the bottom of Challenger Deep, the deepest known point of the Mariana Trench on March 26, 2012. Cameron's submersible was reached a depth of 10,908 metres. More private firms such as Florida based Triton Submarines, LLC.
SEAmagine Hydrospace, Sub Aviator Systems, Netherlands-based U-Boat Worx have developed small submersibles for tourism and adventure travel. A Canadian company in British Columbia called Sportsub has been building personal recreational submersibles since 1986 with open-floor designs. Small unmanned submersibles called "marine remotely operated vehicles" or MROVs are used today to work in water too deep or too dangerous for divers. Remotely operated vehicles repair offshore oil platforms and attach cables to sunken ships to hoist them; such remotely operated vehicles are attached by a tether to a control center on a ship. Operators on the ship see video images sent back from the robot and may control its propellers and manipulator arm; the wreck of the Titanic was explored by such a vehicle, as well as by a manned vessel. Polmar, Norman. "Bathyscaph." World Book Online Reference Center. 2008. Https://web.archive.org/web/20110429001553/http://worldbookonline.com/wb/Article?id=ar049420
Science fiction is a genre of speculative fiction dealing with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, extraterrestrials in fiction. Science fiction explores the potential consequences of scientific other various innovations, has been called a "literature of ideas." "Science fiction" is difficult to define as it includes a wide range of concepts and themes. James Blish wrote: "Wells used the term to cover what we would today call'hard' science fiction, in which a conscientious attempt to be faithful to known facts was the substrate on which the story was to be built, if the story was to contain a miracle, it ought at least not to contain a whole arsenal of them."Isaac Asimov said: "Science fiction can be defined as that branch of literature which deals with the reaction of human beings to changes in science and technology." According to Robert A. Heinlein, "A handy short definition of all science fiction might read: realistic speculation about possible future events, based solidly on adequate knowledge of the real world and present, on a thorough understanding of the nature and significance of the scientific method."Lester del Rey wrote, "Even the devoted aficionado or fan—has a hard time trying to explain what science fiction is," and that the reason for there not being a "full satisfactory definition" is that "there are no delineated limits to science fiction."
Author and editor Damon Knight summed up the difficulty, saying "science fiction is what we point to when we say it." Mark C. Glassy described the definition of science fiction as U. S. Supreme Court Justice Potter Stewart did with the definition of pornography: "I know it when I see it." Science fiction had its beginnings in a time when the line between myth and fact was arguably more blurred than the present day. Written in the 2nd century CE by the satirist Lucian, A True Story contains many themes and tropes that are characteristic of contemporary science fiction, including travel to other worlds, extraterrestrial lifeforms, interplanetary warfare, artificial life; some consider it the first science-fiction novel. Some of the stories from The Arabian Nights, along with the 10th-century The Tale of the Bamboo Cutter and Ibn al-Nafis's 13th-century Theologus Autodidactus contain elements of science fiction. Products of the Age of Reason and the development of modern science itself, Johannes Kepler's Somnium, Francis Bacon's New Atlantis, Cyrano de Bergerac's Comical History of the States and Empires of the Moon and The States and Empires of the Sun, Margaret Cavendish's "The Blazing World", Jonathan Swift's Gulliver's Travels, Ludvig Holberg's Nicolai Klimii Iter Subterraneum and Voltaire's Micromégas are regarded as some of the first true science-fantasy works.
Indeed, Isaac Asimov and Carl Sagan considered Somnium the first science-fiction story. Following the 18th-century development of the novel as a literary form, Mary Shelley's books Frankenstein and The Last Man helped define the form of the science-fiction novel. Brian Aldiss has argued. Edgar Allan Poe wrote several stories considered science fiction, including "The Unparalleled Adventure of One Hans Pfaall" which featured a trip to the Moon. Jules Verne was noted for his attention to detail and scientific accuracy Twenty Thousand Leagues Under the Sea which predicted the contemporary nuclear submarine. In 1887, the novel El anacronópete by Spanish author Enrique Gaspar y Rimbau introduced the first time machine. Many critics consider H. G. Wells one of science fiction's most important authors, or "the Shakespeare of science fiction." His notable science-fiction works include The Time Machine, The Island of Doctor Moreau, The Invisible Man, The War of the Worlds. His science fiction imagined alien invasion, biological engineering and time travel.
In his non-fiction futurologist works he predicted the advent of airplanes, military tanks, nuclear weapons, satellite television, space travel, something resembling the World Wide Web. In 1912, Edgar Rice Burroughs published A Princess of Mars, the first of his three-decade-long planetary romance series of Barsoom novels, set on Mars and featuring John Carter as the hero. In 1926, Hugo Gernsback published the first American science-fiction magazine, Amazing Stories, in which he wrote: By'scientifiction' I mean the Jules Verne, H. G. Wells and Edgar Allan Poe type of story—a charming romance intermingled with scientific fact and prophetic vision... Not only do these amazing tales make tremendously interesting reading—they are always instructive, they supply knowledge... in a palatable form... New adventures pictured for us in the scientifiction of today are not at all impossible of realization tomorrow... Many great science stories destined to be of historical interest are still to be written...
Posterity will point to them as having blazed a new trail, not only in literature and fiction, but progress as well. In 1928, E. E. "Doc" Smith's first published work, The Skylark of Space, written in collaboration with Lee Hawkins Garby, appeared in Amazing Stories. It is called the first great space opera; the same year, Philip Francis Nowlan's original Buck Rogers story, Armageddon 2419 appeared in Amazing Stories. This was followed by the first serious science-fiction comic. In 1937, John W. Campbell became editor of Astounding Science Fiction, an event, sometimes conside
A space station known as an orbital station or an orbital space station, is a spacecraft capable of supporting crewmembers, designed to remain in space for an extended period of time and for other spacecraft to dock. A space station is distinguished from other spacecraft used for human spaceflight by lack of major propulsion or landing systems. Instead, other vehicles transport people and cargo to and from the station; as of 2018, one functioning space station is in Earth orbit: the International Space Station. Various other components of future space stations, such as Japan's space elevator and U. S. inflatable modules, are being tested in orbit. Previous stations include the Almaz and Salyut series, Skylab and Tiangong-1 and Tiangong-2. China, the U. S. as well as a few private companies are all planning other stations for the coming decades. Today's space stations are research platforms, used to study the effects of long-term space flight on the human body as well as to provide platforms for greater number and length of scientific studies than available on other space vehicles.
Each crew member stays aboard the station for weeks or months, but more than a year. Since the ill-fated flight of Soyuz 11 to Salyut 1, all human spaceflight duration records have been set aboard space stations; the duration record for a single spaceflight is 437.7 days, set by Valeriy Polyakov aboard Mir from 1994 to 1995. As of 2016, four cosmonauts have completed single missions of over a year, all aboard Mir. Space stations have been used for both military and civilian purposes; the last military-use space station was Salyut 5, used by the Almaz program of the Soviet Union in 1976 and 1977. Space stations have been envisaged since at least as early as 1869 when Edward Everett Hale wrote "The Brick Moon"; the first to give serious consideration to space stations were Konstantin Tsiolkovsky in the early 20th century and Hermann Oberth about two decades later. In 1929 Herman Potočnik's The Problem of Space Travel was published, the first to envision a "rotating wheel" space station to create artificial gravity.
During the Second World War, German scientists researched the theoretical concept of an orbital weapon based on a space station. Pursuing Oberth's idea of a space-based weapon, the so-called "sun gun" was a concept of a space station orbiting Earth at a height of 8,200 kilometres, with a weapon, to utilize the sun's energy. In 1951, in Collier's Weekly, Wernher von Braun published his design for a rotating wheel space station, which referenced Potočnik's idea – however these concepts would never leave the concept stage during the 20th century. During the same time as von Braun pursued Potočnik's ideas, the Soviet design bureaus – chiefly Vladimir Chelomey's OKB-52 – were pursuing Tsiolkovsky's ideas for space stations; the work by OKB-52 would lead to the Almaz programme and to the first space station: Salyut 1. The developed hardware laid the ground for the Salyut and Mir space stations, is today a considerable part of the ISS space station; the first space station was Salyut 1, launched by the Soviet Union on April 19, 1971.
Like all the early space stations, it was "monolithic", intended to be constructed and launched in one piece, inhabited by a crew later. As such, monolithic stations contained all their supplies and experimental equipment when launched, were considered "expended", abandoned, when these were used up; the earlier Soviet stations were all designated "Salyut", but among these there were two distinct types: civilian and military. The military stations, Salyut 2, Salyut 3, Salyut 5, were known as Almaz stations; the civilian stations Salyut 6 and Salyut 7 were built with two docking ports, which allowed a second crew to visit, bringing a new spacecraft with them. This allowed for a crew to man the station continually. Skylab was equipped with two docking ports, like second-generation stations, but the extra port was never utilized; the presence of a second port on the new stations allowed Progress supply vehicles to be docked to the station, meaning that fresh supplies could be brought to aid long-duration missions.
This concept was expanded on Salyut 7, which "hard docked" with a TKS tug shortly before it was abandoned. The Salyuts may reasonably be seen as a transition between the two groups. Unlike previous stations, the Soviet space station Mir had a modular design; this method allows for greater flexibility in operation, as well as removing the need for a single immensely powerful launch vehicle. Modular stations are designed from the outset to have their supplies provided by logistical support, which allows for a longer lifetime at the cost of requiring regular support launches. Future modules are still based on initial design and capabilities; the first module of the International Space Station, was launched in 1998. The ISS is divided into the Russian Orbital Segment and the US Orbital Segment. USOS modules were brought to the station by the Space Shuttle and manually attached to the ISS by crews during EVAs. Connections are made manually for electrical power, data and cooling fluids; this results in a single piece, not designed for disassembly.
The Russian Orbital Segment's modules are able to launch and dock themselves without human intervention usin
A torpedo tube is a cylinder shaped device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, deck-mounted units installed aboard surface vessels. Deck-mounted torpedo launchers are designed for a specific type of torpedo, while submarine torpedo tubes are general-purpose launchers, are also capable of deploying mines and cruise missiles. Most modern launchers are standardised on a 12.75-inch diameter for light torpedoes or a 21-inch diameter for heavy torpedoes, although other sizes of torpedo tube have been used: see Torpedo classes and diameters. A submarine torpedo tube is a more complex mechanism than a torpedo tube on a surface ship, because the tube has to accomplish the function of moving the torpedo from the normal atmospheric pressure within the submarine into the sea at the ambient pressure of the water around the submarine, thus a submarine torpedo tube operates on the principle of an airlock. The diagram on the right illustrates the operation of a submarine torpedo tube.
The diagram does show the working of a submarine torpedo launch. A torpedo tube has a considerable number of interlocks for safety reasons. For example, an interlock prevents the breech muzzle door from opening at the same time; the submarine torpedo launch sequence is, in simplified form: Open the breech door in the torpedo room. Load the torpedo into the tube. Hook up the wire-guide connection and the torpedo power cable. Shut and lock the breech door. Turn on power to the torpedo. A minimum amount of time is required for torpedo warmup. Fire control programs are uploaded to the torpedo. Flood the torpedo tube; this may be done manually or automatically, from sea or from tanks, depending on the class of submarine. The tube must be vented during this process to allow for complete filling and eliminate air pockets which could escape to the surface or cause damage when firing. Open the equalizing valve to equalize pressure in the tube with ambient sea pressure. Open the muzzle door. If the tube is set up for Impulse Mode the slide valve will open with the muzzle door.
If Swim Out Mode is selected, the slide valve remains closed. The slide valve allows water from the ejection pump to enter the tube; when the launch command is given and all interlocks are satisfied, the water ram operates, thrusting a large volume of water into the tube at high pressure, which ejects the torpedo from the tube with considerable force. Modern torpedoes have a safety mechanism that prevents activation of the torpedo unless the torpedo senses the required amount of G-force; the power cable is severed at launch. However, if a guidance wire is used, it remains connected through a drum of wire in the tube. Torpedo propulsion systems vary but electric torpedoes swim out of the tube on their own and are of a smaller diameter. 21" weapons with fuel-burning engines start outside the tube. Once outside the tube the torpedo begins its run toward the target as programmed by the fire control system. Attack functions are programmed but with wire guided weapons, certain functions can be controlled from the ship.
For wire-guided torpedoes, the muzzle door must remain open because the guidance wire is still connected to the inside of the breech door to receive commands from the submarine's fire-control system. A wire cutter on the inside of the breech door is activated to release the wire and its protective cable; these are drawn clear of the ship prior to shutting the muzzle door. The drain cycle is a reverse of the flood cycle. Water can be moved as necessary; the tube must be vented to drain the tube since it is by gravity. Open the breech door and remove the remnants of the torpedo power cable and the guidance wire basket; the tube must be wiped dry to prevent a buildup of slime. This process is called "diving the tube" and tradition dictates that "ye who shoots, dives". Shut and lock the breech door. Spare torpedoes are stored behind the tube in racks. Speed is a desirable feature of a torpedo loading system. There are various manual and hydraulic handling systems for loading torpedoes into the tubes. Prior to the Ohio class, US SSBNs utilized manual block and tackle which took about 15 minutes to load a tube.
SSNs prior to the Seawolf class used a hydraulic system, much faster and safer in conditions where the ship needed to maneuver. The German Type 212 submarine uses a new development of the water ram expulsion system, which ejects the torpedo with water pressure to avoid acoustic detection. List of torpedoes by diameter The Fleet Type Submarine Online 21-Inch Submerged Torpedo Tubes United States Navy Restricted Ordnance Pamphlet 1085, June 1944 Torpedo tubes of German U-Boats
BioShock is a first-person shooter video game series developed by Irrational Games—the first under the name 2K Boston/2K Australia—and designed by Ken Levine. The series is considered a spiritual successor to the System Shock series, on which many of Irrational's team including Levine had worked previously. Additionally, the series is notable for exploring philosophical concepts; the first game in the series was released for the Windows operating system and Xbox 360 video game console on August 21, 2007 in North America, on August 24 in Europe and Australia. A PlayStation 3 version of the game, developed by 2K Marin, was released internationally on October 17, 2008 and in North America on October 21, 2008 with some additional features; the game was released for the Mac OS X operating system on October 7, 2009. A version of the game for mobile platforms has been developed by IG Fun. A sequel, BioShock 2, was released on February 9, 2010. On August 12, 2010, Irrational Games unveiled a trailer for a new game titled BioShock Infinite, released on March 26, 2013.
With the release of BioShock Infinite selling over 11 million copies as of May 2015, the three games combined have more than 25 million copies sold, making it one of the best selling video game franchises of all time. A fourth game to the series is under the working name Parkside. In response to a question from the gaming website IGN about what influenced the game's story and setting, Levine said, "I have my useless liberal arts degree, so I've read stuff from Ayn Rand, George Orwell and all the sort of utopian and dystopian writings of the 20th century, having developed the System Shock franchise, some of my first games, I felt that the atmosphere was a good one to set for a dystopian environment, one we borrowed from System Shock." Levine has mentioned an interest in "stem cell research and the moral issues that go around." In regard to artistic influences, Levine cited the books Nineteen Eighty-Four and Logan's Run, representing societies that have "really interesting ideas screwed up by the fact that we're people."According to the developers, BioShock is a spiritual successor to the System Shock games, was produced by former developers of that series.
Levine claims his team had been thinking about making another game in the same vein since they produced System Shock 2. In his narration of a video screened for the press at E3 2006, Levine pointed out many similarities between the games. There are several comparable gameplay elements: plasmids in BioShock supplied by "EVE hypos" serve the same function as "Psionic Abilities" supplied by "PSI hypos" in System Shock 2; the "ghosts" from System Shock 2 exist in BioShock, as do modifiable weapons with multiple ammunition types and researching enemies for increased damage. Additionally, Atlas guides the player along by radio, in much the same way Janice Polito does in System Shock 2, with each having a similar twist mid-game. Both games give the player more than one method of completing tasks, allowing for emergent gameplay. In the reveal of the third game of the series, BioShock Infinite, Ken Levine stated that the name "BioShock" is not in reference to any specific setting or location, but instead a means of encapsulating common gameplay elements that reflects on their earlier games such as System Shock 2, the BioShock series.
To me, there's two things. They take place in a world, both fantastic and ridiculous. Something that you've never seen before and something that nobody else could create except Irrational, but it's strangely grounded and believable; the other thing that makes it a BioShock game, it's about having a huge toolset of power and a huge range of challenges, you being able to drive how you solve those challenges. In a conversation over Twitter in 2017 a former artist who worked on'Infinite' compared the game series to the Far Cry series, saying that "I think what makes a Bioshock game, or at least a good Bioshock game, is that sense of magical realism. I think it's a lot like what Dan Hay said about what he thinks a good Far Cry game is, you know, this sense that this stuff could happen in real life, like someone sits down next to you at a bar or wherever and starts telling you this story that's so fantastic that you're super skeptical, but everything in the story is 100% plausible and you come away feeling like that story was legit.
What we do is we add magical realism to it, so the fallen city becomes an underwater dystopia, the druggies become these psychic mutants and people driven insane by using drugs that make them superhumans." The games in the BioShock series are first-person shooters. The series is considered the spiritual successor to System Shock 2, which many of the developers were involved with through Irrational Games. While specific mechanics differ between all three games, they share a common theme of having the player use a combination of physical weapons such as guns and melee weapons, superhuman powers—including both active and passive abilities—granted by genetic alterations (pla
An aviary is a large enclosure for confining birds. Unlike birdcages, aviaries allow birds a larger living space. Aviaries contain plants and shrubbery to simulate a natural environment. Large aviaries are found in the setting of a zoological garden. Spacious walk-in aviaries exist in bird parks such as Jurong BirdPark in Singapore. Pittsburgh is home to the USA's National Aviary the most prominent example in North America of an aviary not set inside a zoo; the Tracy Aviary is an example of a bird park within a public urban park, Liberty Park in Salt Lake City, Utah. Some smaller sized aviaries can be found in European manorial gardens, such as Waddesdon Manor, UK, Versailles, France; some public aquaria, such as the Oregon Coast Aquarium, Oregon, or the Monterey Bay Aquarium, have aquatic aviaries. Home aviaries are popular with some bird fanciers. Many bird breeders list themselves as "aviaries", since most bird pairs breed best in aviaries in contrast to breeding cages. Home aviaries may be obtained from a commercial supplier.
There are two main subcategories of home aviaries: suspended aviaries. Grounded aviaries are affixed to the ground with a concrete base to prevent rats and other vermin from entering. Suspended aviaries are suspended in the air with only the'legs' of the aviaries affixed to the ground. Most grounded aviaries feature a woodwork or PVC frame unlike the metal frame of public aviaries. An aviary, a large cage to house and display birds, dates as far back and earlier than the 1500s found in the Aztec city of Tenochtitlan as noted by Hernan Cortes when he and his men arrived in 1521; the Raven Cage, is regarded as one of the oldest structures in the London Zoo. The first large aviary inside a zoological garden was established in 1880 in the setting of the Rotterdam Zoo. Aviaries were an important aspect for the many Rothschild houses that proliferated across Europe in the 19th century; this was a recalling of the aristocratic custom from the late 1600s, which involved the elite society displaying their power and wealth through the exhibition of exotic birds and animals.
For instance, Baron Ferdinand de Rothschild built his aviary in 1889 at Waddesdon Manor, UK, erected in the style of Versailles' trelliswork pavilions. In 1902, a flying cage was completed in the setting of the National Zoological Park of the Smithsonian Institution. A new Great Flying Cage was built in 1964; the Saint Louis Zoo is home to the 1904 World's Fair Flight Cage. It is one of only two permanent structures built for the World's Fair. In 1904, it was the largest bird cage built, it remains one of the world's largest free-flight aviaries. The 69 m long, 26 m wide, 15 m high cage was built by the Smithsonian Institution for the St. Louis World's Fair. Local pride in the giant cage motivated St. Louis to establish a zoo in 1910. In 1937, the San Diego Zoo's aviary designed by architect Louis John Gill opened; the mammoth steel structure, 55 m long, 18 m wide and more than 30 m high, funded by the Works Progress Administration at a cost of $50,000, had no beams, cross or guy-wires to impede the flight of the birds.
With the Antwerp cage system, birds are only separate from public with a light system used indoor the Bird Building at Antwerp Zoo. At the Frankfurt Zoo, the bird house was built in 1969, its Bird Halls presented birds for the first time in large glassed miniature habitats. In diving exhibits and kingfishers could be seen hunting under water, in the free-flight hall visitors still walk amongst tropical birds in dense vegetation. In 1963, the same principle was used outdoors to construct the Bird Thicket, ten aviaries surrounded by dense bushes and designed in various habitat settings, which visitors can enter through wire netted doors and curtains of cords; the Snowdon Aviary in London Zoo was designed by Antony Armstrong-Jones, 1st Earl of Snowdon, Cedric Price and Frank Newby, built in 1962-1964. The Bronx Zoo's World of Birds, a two-story bird house completed in 1972, is a huge, indoor free-flight exhibit; the one-way flow pattern in the exhibit moves the visitors through twenty-five birds habitats, ranging from desert to tropical forest.
Each setting recreates with impressive fidelity the microculture of the birds that fly merrily about within their diorama world, complete with living plants. Five of the aviaries are open: in two of the largest the uncaged public walks through the habitat with birds overhead; the Henry Doorly Zoo's Simmons Aviary opened in 1983 and is one of the world's largest free-flight aviaries. About 500 birds from all parts of the world occupy the area of the aviary. In this 16,000-square-metre exhibit, visitors see flamingos, swans, cranes, spoonbills and egrets; the Aviary rises to 23 m at the center. The structure of two-inch nylon mesh is supported by a system of poles; the use of nylon instead of wire is a unique concept. Birds of Eden bird sanctuary, located in the Western Cape of South Africa, is the largest free flight aviary in the world; the aviary opened in 2005 and covers an area of 21,761 m2 with a total volume of 375,372 m3