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Buoyancy Engine
A buoyancy engine is a device that alters the buoyancy of a vehicle or object in order to either move it vertically, as in the case of underwater profiling floats and stealth buoys, or provide forward motion (therefore providing variable-buoyancy propulsion) such as with underwater gliders and some autonomous aircraft. For underwater applications, buoyancy engines typically involve a hydraulic pump that either inflates and deflates an external bladder filled with hydraulic fluid, or extends and retracts a rigid plunger. The change in the vehicle's total volume alters its buoyancy, making it float upwards or sink as required. Alternative systems employing gas obtained from water electrolysis, rather than hydraulic fluid, have also been proposed. as have systems which pump ambient water into and out of a pressure vessel Operation The buoyancy engine is a fairly new piece of technology currently in research by many institutions and organizations that utilize underwater surveil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buoyancy Engine
A buoyancy engine is a device that alters the buoyancy of a vehicle or object in order to either move it vertically, as in the case of underwater profiling floats and stealth buoys, or provide forward motion (therefore providing variable-buoyancy propulsion) such as with underwater gliders and some autonomous aircraft. For underwater applications, buoyancy engines typically involve a hydraulic pump that either inflates and deflates an external bladder filled with hydraulic fluid, or extends and retracts a rigid plunger. The change in the vehicle's total volume alters its buoyancy, making it float upwards or sink as required. Alternative systems employing gas obtained from water electrolysis, rather than hydraulic fluid, have also been proposed. as have systems which pump ambient water into and out of a pressure vessel Operation The buoyancy engine is a fairly new piece of technology currently in research by many institutions and organizations that utilize underwater surveil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autonomous Underwater Vehicle
An autonomous underwater vehicle (AUV) is a robot that travels underwater without requiring input from an operator. AUVs constitute part of a larger group of undersea systems known as unmanned underwater vehicles, a classification that includes non-autonomous remotely operated underwater vehicles (ROVs) – controlled and powered from the surface by an operator/pilot via an umbilical or using remote control. In military applications an AUV is more often referred to as an unmanned undersea vehicle (UUV). Underwater gliders are a subclass of AUVs. History The first AUV was developed at the Applied Physics Laboratory at the University of Washington as early as 1957 by Stan Murphy, Bob Francois and later on, Terry Ewart. The "Special Purpose Underwater Research Vehicle", or SPURV, was used to study diffusion, acoustic transmission, and submarine wakes. Other early AUVs were developed at the Massachusetts Institute of Technology in the 1970s. One of these is on display in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passenger Ship
A passenger ship is a merchant ship whose primary function is to carry passengers on the sea. The category does not include cargo vessels which have accommodations for limited numbers of passengers, such as the ubiquitous twelve-passenger freighters once common on the seas in which the transport of passengers is secondary to the carriage of freight. The type does however include many classes of ships designed to transport substantial numbers of passengers as well as freight. Indeed, until recently virtually all ocean liners were able to transport mail, package freight and express, and other cargo in addition to passenger luggage, and were equipped with cargo holds and derricks, kingposts, or other cargo-handling gear for that purpose. Only in more recent ocean liners and in virtually all cruise ships has this cargo capacity been eliminated. While typically passenger ships are part of the merchant marine, passenger ships have also been used as troopships and often are commissio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airliner
An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an airplane intended for carrying multiple passengers or cargo in commercial service. The largest of them are wide-body jets which are also called twin-aisle because they generally have two separate aisles running from the front to the back of the passenger cabin. These are usually used for long-haul flights between airline hubs and major cities. A smaller, more common class of airliners is the narrow-body or single-aisle. These are generally used for short to medium-distance flights with fewer passengers than their wide-body counterparts. Regional airliners typically seat fewer than 100 passengers and may be powered by turbofans or turboprops. These airliners are the non- mainline counterparts to the larger aircraft operated by the major car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wreckage
Wreckage may refer to: * Debris Music * ''Wreckage'' (album), a 2002 album by Overseer * ''Wreckage'' (1969 band), a late 1960s band notable for featuring future Queen vocalist Freddie Mercury as a member * ''Wreckage'', a 1997 EP by the band Entombed * "Wreckage", a song by Combichrist from ''Everybody Hates You'' * "Wreckage", a song by the J. Geils Band from ''Monkey Island ''Monkey Island'' is a series of adventure games. The first four games in the series were produced and published by LucasArts, earlier known as Lucasfilm Games. The fifth installment of the franchise was developed by Telltale Games in collabor ...'' * "Wreckage", a song by Parkway Drive from '' Deep Blue'' Other uses * Wreckage (G.I. Joe), a character in the G.I. Joe universe See also * Wreck (other) * * * The Wreckage (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Buoyancy Pressure Vessel
A variable buoyancy pressure vessel system is a type of rigid buoyancy control device for diving systems that retains a constant volume and varies its density by changing the weight (mass) of the contents, either by moving the ambient fluid into and out of a rigid pressure vessel, or by moving a stored liquid between internal and external variable volume containers. A pressure vessel is used to withstand the hydrostatic pressure of the underwater environment. A variable buoyancy pressure vessel can have an internal pressure greater or less than external ambient pressure, and the pressure difference can vary from positive to negative within the operational depth range, or remain either positive or negative throughout the pressure range, depending on design choices. Variable buoyancy is a useful characteristic of any mobile underwater system that operates in mid-water without external support. Examples include submarines, submersibles, benthic landers, remotely operated and autonomo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density
Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematically, density is defined as mass divided by volume: : \rho = \frac where ''ρ'' is the density, ''m'' is the mass, and ''V'' is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume, although this is scientifically inaccurate – this quantity is more specifically called specific weight. For a pure substance the density has the same numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging. Osmium and iridium are the densest known elements at standard conditions for temperature and pressure. To simplify comparisons of density across different s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glider (aircraft)
A glider is a fixed-wing aircraft that is supported in flight by the dynamic reaction of the air against its lifting surfaces, and whose free flight does not depend on an engine. Most gliders do not have an engine, although motor-gliders have small engines for extending their flight when necessary by sustaining the altitude (normally a sailplane relies on rising air to maintain altitude) with some being powerful enough to take off by self-launch. There are a wide variety of types differing in the construction of their wings, aerodynamic efficiency, location of the pilot, controls and intended purpose. Most exploit meteorological phenomena to maintain or gain height. Gliders are principally used for the air sports of gliding, hang gliding and paragliding. However some spacecraft have been designed to descend as gliders and in the past military gliders have been used in warfare. Some simple and familiar types of glider are toys such as paper planes and balsa wood gliders. Etym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Electrolysis
Electrolysis of water, also known as electrochemical water splitting, is the process of using electricity to decompose water into oxygen and hydrogen gas by electrolysis. Hydrogen gas released in this way can be used as hydrogen fuel, or remixed with the oxygen to create oxyhydrogen gas, which is used in welding and other applications. Electrolysis of water requires a minimum potential difference of 1.23 volts, though at that voltage external heat is required. E lectrolysis is rarely used in industrial applications since hydrogen can be produced less expensively from fossil fuels. History In 1789, Jan Rudolph Deiman and Adriaan Paets van Troostwijk used an electrostatic machine to make electricity that was discharged on gold electrodes in a Leyden jar with water. In 1800 Alessandro Volta invented the voltaic pile, and a few weeks later English scientists William Nicholson and Anthony Carlisle used it to electrolyse water. In 1806 Humphry Davy reported the results of ext ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buoyancy
Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. The pressure difference results in a net upward force on the object. The magnitude of the force is proportional to the pressure difference, and (as explained by Archimedes' principle) is equivalent to the weight of the fluid that would otherwise occupy the submerged volume of the object, i.e. the displaced fluid. For this reason, an object whose average density is greater than that of the fluid in which it is submerged tends to sink. If the object is less dense than the liquid, the force can keep the object afloat. This can occur only in a no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Fluid
A hydraulic fluid or hydraulic liquid is the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water. Examples of equipment that might use hydraulic fluids are excavators and backhoes, hydraulic brakes, power steering systems, automatic transmissions, garbage trucks, aircraft flight control systems, lifts, and industrial machinery. Hydraulic systems like the ones mentioned above will work most efficiently if the hydraulic fluid used has zero compressibility. Functions and properties The primary function of a hydraulic fluid is to convey power. In use, however, there are other important functions of hydraulic fluid such as protection of the hydraulic machine components. The table below lists the major functions of a hydraulic fluid and the properties of a fluid that affect its ability to perform that function: Composition Base stock The original hydraulics fluid, dating back to the time of ancient Egypt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Pump
Hydraulic pumps are used in hydraulic drive systems and can be hydrostatic or hydrodynamic. A hydraulic pump is a mechanical source of power that converts mechanical power into hydraulic energy ( hydrostatic energy i.e. flow, pressure). It generates flow with enough power to overcome pressure induced by the load at the pump outlet. When a hydraulic pump operates, it creates a vacuum at the pump inlet, which forces liquid from the reservoir into the inlet line to the pump and by mechanical action delivers this liquid to the pump outlet and forces it into the hydraulic system. Hydrostatic pumps are positive displacement pumps while hydrodynamic pumps can be fixed displacement pumps, in which the displacement (flow through the pump per rotation of the pump) cannot be adjusted, or variable displacement pumps, which have a more complicated construction that allows the displacement to be adjusted. Hydrodynamic pumps are more frequent in day-to-day life. Hydrostatic pumps of various types ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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