"is about . Hydrogen, being the lightest existing gas (7% the density of air), seems to be the most appropriate gas for lifting. But hydrogen has several disadvantages: Helium is the second lightest gas. For that reason, it is an attractive gas for lifting as well. Small size of helium molecules increases its lifting value. A major advantage is that this gas is noncombustible. But the use of helium has some disadvantages, too: The gaseous state of water is lighter than air, incombustible and much cheaper than helium. The concept of using steam for lifting is therefore already 200 years"
"Gallows A gallows (or scaffold) is a frame, typically wooden, from which objects can be hung or “weighed.” Gallows were thus widely used for public weighing scales for large objects such as sacks of grain or minerals, usually positioned in markets or toll gates. The term was also used for a framework from which an ship’s anchor might be raised so that it no longer sat on the bottom, i.e., “weighing [the] anchor.” In modern usage it has come to mean almost exclusively a scaffold or gibbet used for execution by hanging. Public weighing gallows were often large permanent tripods"
"Futtock shrouds Futtock shrouds are rope, wire or chain links in the rigging of a traditional square rigged ship. They run from the outer edges of a top downwards and inwards to a point on the mast or lower shrouds, and carry the load of the shrouds that rise from the edge of the top. This prevents any tendency of the top itself to tilt relative to the mast. In the most traditional ships, the futtock shrouds can be used to gain access to the tops. Sailors ascend ratlines on the ordinary shrouds until nearly at the top, then transfer"
"readiness level of 2. Skyhook (structure) A skyhook is a proposed momentum exchange tether that aims to reduce the cost of placing payloads into space. A heavy orbiting station is connected to a cable which extends down towards the upper atmosphere. Payloads, which are much lighter than the station, are hooked to the end of the cable as it passes, and are then flung into orbit by rotation of the cable around the centre of mass. The station can then be reboosted to its original altitude by electromagnetic propulsion, rocket propulsion, or by deorbiting another object equal in mass to"
"Lift-on/lift-off Lift-on/lift-off or LoLo<ref name=""http://www.globalsecurity.org""></ref> ships are cargo ships with on-board cranes to load and unload cargo. While the common abbreviation of ""lift-on/lift-off"" is ""LoLo"", it is sometimes abbreviated as ""LOLO"", ""LO/LO"" or ""Lo/Lo"". Ships with cranes or other cargo handling equipment on-board are also termed ""geared"" vessels. As container ships usually have no on-board cranes or other mechanism to load or unload their cargo, they are therefore dependent on dockside container cranes to load and unload. However lift-on/lift-off vessels can load and unload their own cargo unassisted. Lift-on/lift-off vessels can operate out of docks with no dockside cargo handling"
"Skyhook (structure) A skyhook is a proposed momentum exchange tether that aims to reduce the cost of placing payloads into space. A heavy orbiting station is connected to a cable which extends down towards the upper atmosphere. Payloads, which are much lighter than the station, are hooked to the end of the cable as it passes, and are then flung into orbit by rotation of the cable around the centre of mass. The station can then be reboosted to its original altitude by electromagnetic propulsion, rocket propulsion, or by deorbiting another object equal in mass to the payload. A skyhook"
"Lift table A lift table is a device that employs a scissors mechanism to raise or lower goods and/or persons. Typically lift tables are used to raise large, heavy loads through relatively small distances. Common applications include pallet handling, vehicle loading and work positioning. Lift tables are a recommended way to help reduce incidents of musculoskeletal disorders by correctly re-positioning work at a suitable height for operators. Lift tables lend themselves to being easily adapted to a specific use. They can work in hostile environments, be manufactured in stainless steel and have equipment like conveyors, turn-tables, barriers and gates easily"
"Shiplift A shiplift is a modern alternative for a slipway, a floating dry dock or a graving dry dock. A shiplift is used to dry dock and launch ships. It consists of a structural platform that is lifted and lowered exactly vertically, synchronously by a number of hoists. First, the platform is lowered underwater, then the ship is floated above the support, and finally the platform with support and ship is lifted and the ship is brought to the level of the quay. Nowadays, shiplift are most of the time supplied under rules of a classification authority. Lloyd's Register of"
"Shoulder shrug The shoulder shrug (usually called simply the shrug) is an exercise in weight training used to develop the upper trapezius muscle. The lifter stands erect, hands about shoulder width apart, and raises the shoulders as high as possible, and then lowers them, while not bending the elbows, or moving the body at all. The lifter may not have as large a range of motion as in a normal shrug done for active flexibility. It is usually considered good form if the slope of the shoulders is horizontal in the elevated position. A barbell, dumbbells or a smith machine"
"Shoulder shrug The shoulder shrug (usually called simply the shrug) is an exercise in weight training used to develop the upper trapezius muscle. The lifter stands erect, hands about shoulder width apart, and raises the shoulders as high as possible, and then lowers them, while not bending the elbows, or moving the body at all. The lifter may not have as large a range of motion as in a normal shrug done for active flexibility. It is usually considered good form if the slope of the shoulders is horizontal in the elevated position. A barbell, dumbbells or a smith machine"
"Skyhook (cable) A skyhook is a ""hook"" used to lift an object on a long cable hanging from the sky, without readily apparent support. In the mid-20th century it was common in the Boy Scouts and occupations such as oil drilling to send new recruits on a futile search for such an imaginary object, as a practical joke. The term has subsequently lent its name to some real mechanisms that use an airborne hook or hoist, and to other products or ideas that allude to the concept. The American philosopher Richard Rorty uses the term to refer to a hypothetical"
"Topping lift The topping lift (more rarely known as an uphaul) is a line which applies upward force on a boom on a sailboat. Part of the running rigging, topping lifts are primarily used to hold a boom up when the sail is lowered. This line would run from near the free end of the boom(s) forward to the top of the mast. The line may be run over a block at the top of the mast and down to the deck to allow it to be adjusted. For small booms, the topping lift may be run from end of"
"also available in especially compact form, to fit through doorways for use inside buildings. A scissor lift is a type of platform that can usually only move vertically. The mechanism to achieve this is the use of linked, folding supports in a criss-cross ""X"" pattern, known as a pantograph (or scissor mechanism). The upward motion is achieved by the application of pressure to the outside of the lowest set of supports, elongating the crossing pattern, and propelling the work platform vertically. The platform may also have an extending ""bridge"" to allow closer access to the work area, because of the"
"other motive force and smaller aerodynamic vehicles, propelling them to hypersonic velocities without exotic propulsion systems. A skyhook is a theoretical class of orbiting tether propulsion intended to lift payloads to high altitudes and speeds. Proposals for skyhooks include designs that employ tethers spinning at hypersonic speed for catching high speed payloads or high altitude aircraft and placing them in orbit. A space elevator is a proposed type of space transportation system. Its main component is a ribbon-like cable (also called a tether) anchored to the surface and extending into space above the level of geosynchronous orbit. As the planet"
"Lift-off (microtechnology) Lift-off process in microstructuring technology is a method of creating structures (patterning) of a target material on the surface of a substrate (e.g. wafer) using a sacrificial material (e.g., Photoresist). It is an additive technique as opposed to more traditional subtracting technique like etching. The scale of the structures can vary from the nanoscale up to the centimeter scale or further, but are typically of micrometric dimensions. An inverse pattern is first created in the sacrificial stencil layer (ex. photoresist), deposited on the surface of the substrate. This is done by etching openings through the layer so that"
"Shabbat elevator A Shabbat elevator is an elevator which works in a special mode, operating automatically, to satisfy the Jewish law requiring Jews to abstain from operating electrical switches on Shabbat (the Sabbath). Jewish law forbids those who observe it from undertaking various forms of ""work"" on the Sabbath, including that they may not create sparks or fires. In recent times, this has been extrapolated to also cover the operation of electrical equipment. An elevator may be marked with a sign noting that it is specially configured for Shabbat observance. There are several ways the elevator works (going up and"
"Mist lift The Mist lift, Mist flow or Steam lift pump is a gas lift technique of lifting water used in a form of Ocean Thermal Energy Conversion (OTEC) where water falls to operate a hydro-electric turbine. The water is pumped from the level it drops to using rising steam which is combined into a multiphase flow. Independent of energy production, the technique can be used simply as a thermally powered pump used to raise ocean water from depths for unspecified uses. As in other open cycle OTEC schemes, the technique involves boiling seawater under low atmospheric pressure. The scheme"
"Lifting bag A lifting bag is an item of diving equipment consisting of a robust and air-tight bag with straps, which is used to lift heavy objects underwater by means of the bag's buoyancy. The heavy object can either be moved horizontally underwater by the diver or sent unaccompanied to the surface. Lift bag appropriate capacity should match the task at hand. If the lift bag is grossly oversized a runaway or otherwise out of control ascent may result. Commercially available lifting bags may incorporate dump valves to allow the operator to control the buoyancy during ascent, but this is"
"selective removal of branches throughout the canopy of the tree. This is a common practice which improves the tree's strength against adverse weather conditions as the wind can pass through the tree resulting in less ""load"" being placed on the tree. The shape is vital for the survival of the tree and lopping off the wrong sections of a tree if it has surpassed its height limit can actually be extremely damaging. This can hinder its growth or cause an overbalance. Crown lifting involves the removal of the lower branches to a given height. The height is achieved by the"
"Hold down (structural engineering) Holdown (hold-down, hold down) or tie-down in structural engineering refers to the steel device or hardware that is installed at the end of a plywood shear wall. The holdowns provide uplift resistance against the overturning moment imposed on the wall due to ""in-plane"" lateral load applied at the top of the wall. A hold-down may also refer to clamping device used to anchor a pipe to a structural steel element or concrete floor or allow movement of the pipe in an axial direction. At the bottom, the holdown is connected to the concrete foundation or structural"
"Ridge lift Ridge lift (or 'slope lift') is created when a wind strikes an obstacle, usually a mountain ridge or cliff, that is large and steep enough to deflect the wind upward. If the wind is strong enough, the ridge lift provides enough upward force for gliders, hang gliders, paragliders and birds to stay airborne for long periods or travel great distances by 'slope soaring'. Although unpowered aircraft are usually descending through the air, they will climb if the surrounding air is rising faster than their sink rates. Model glider enthusiasts refer to this technique as ""slope gliding"" or ""sloping""."
"Assisted take-off Assisted takeoff is any system for helping aircraft to get into the air (as opposed to strictly under its own power). The reason it might be needed is due to the aircraft's weight exceeding the normal maximum takeoff weight, insufficient power, insufficient available runway length, or a combination of all three factors. Assisted takeoff is also required for gliders, which do not have an engine and are unable to take off by themselves. A well-known type of assisted takeoff is an aircraft catapult. In modern systems fitted on aircraft carriers, a piston, known as a ""shuttle"", is propelled"
"metaphysical system that leads to a universal perspective. Skyhook (cable) A skyhook is a ""hook"" used to lift an object on a long cable hanging from the sky, without readily apparent support. In the mid-20th century it was common in the Boy Scouts and occupations such as oil drilling to send new recruits on a futile search for such an imaginary object, as a practical joke. The term has subsequently lent its name to some real mechanisms that use an airborne hook or hoist, and to other products or ideas that allude to the concept. The American philosopher Richard Rorty"
"a system used for the launch and recovery of aircraft from the deck of an aircraft carrier, combining elements of both STOVL and CATOBAR. Aircraft launch under their own power using a ski-jump to assist take-off (rather than using a catapult). These are conventional aircraft however and require arresting wires to land on the ship. The Russian Navy aircraft carrier operated the Su-33, in this manner. Others include the Indian and the future ; both will operate MiG-29Ks. Prior to World War II, the weight of most aircraft allowed them to be launched from aircraft carriers under their own power,"
"Boat lift A boat lift, ship lift, or lift lock is a machine for transporting boats between water at two different elevations, and is an alternative to the canal lock and the canal inclined plane. It may be either vertically moving, like the ship lifts in Germany, Belgium, the lift at ""Les Fontinettes"" in France or the Anderton boat lift in England, or rotational, like the Falkirk Wheel in Scotland. A precursor to the canal boat lift, able to move full-sized canal boats, was the tub boat lift used in mining, able to raise and lower the 2.5 ton tub"
"as it opens the doors on every floor up the building. Shabbat elevator A Shabbat elevator is an elevator which works in a special mode, operating automatically, to satisfy the Jewish law requiring Jews to abstain from operating electrical switches on Shabbat (the Sabbath). Jewish law forbids those who observe it from undertaking various forms of ""work"" on the Sabbath, including that they may not create sparks or fires. In recent times, this has been extrapolated to also cover the operation of electrical equipment. An elevator may be marked with a sign noting that it is specially configured for Shabbat"
"aerobatic manoeuvres, or on the wing on a racing car. Lift may also be largely horizontal, for instance on a sailing ship. The Lift discussed in this article is mainly in relation to airfoils, although marine hydrofoils and propellers share the same physical principles and work in the same way, despite differences between air and water such as density, compressibility, and viscosity. An airfoil is a streamlined shape that is capable of generating significantly more lift than drag. A flat plate can generate lift, but not as much as a streamlined airfoil, and with somewhat higher drag. There are several"
"Power take-off A power take-off or power takeoff (PTO) is any of several methods for taking power from a power source, such as a running engine, and transmitting it to an application such as an attached implement or separate machines. Most commonly, it is a splined drive shaft installed on a tractor or truck allowing implements with mating fittings to be powered directly by the engine. Semi-permanently mounted power take-offs can also be found on industrial and marine engines. These applications typically use a drive shaft and bolted joint to transmit power to a secondary implement or accessory. In the"
"when completed. Boat lift A boat lift, ship lift, or lift lock is a machine for transporting boats between water at two different elevations, and is an alternative to the canal lock and the canal inclined plane. It may be either vertically moving, like the ship lifts in Germany, Belgium, the lift at ""Les Fontinettes"" in France or the Anderton boat lift in England, or rotational, like the Falkirk Wheel in Scotland. A precursor to the canal boat lift, able to move full-sized canal boats, was the tub boat lift used in mining, able to raise and lower the 2.5"
"sail and cause it to lose its shape. When tacking, the new windward lift must be tightened and the new leeward lift let out. A topping lift may also refer to a line on the front of the mast used to rig the spinnaker pole. It is used to trim the pole to the proper height when hoisting the spinnaker. Topping lift The topping lift (more rarely known as an uphaul) is a line which applies upward force on a boom on a sailboat. Part of the running rigging, topping lifts are primarily used to hold a boom up when"
"this is known as orographic lift. The wind creates a region of rising air directly above the slope, which may extend some distance upwards and outwards from its face because the airflow follows the upward contour of the hill. However, at near vertical cliffs, there is usually an area of turbulence with descending air near the base of the cliff. Downwind of the hill, lee waves can form; these are also used by glider pilots to gain height, but this should not be confused with slope lift. Near slopes rather than vertical cliffs, the strongest lift is often to be"
"Airdrop An airdrop is a type of airlift, developed during World War II to resupply otherwise inaccessible troops, who themselves may have been airborne forces. In some cases, it is used to refer to the airborne assault itself. Early airdrops were conducted by dropping or pushing padded bundles from aircraft. Later small crates with parachutes were pushed out of the aircraft's side cargo doors. Later cargo aircraft were designed with rear access ramps, lowerable in flight, that allowed large platforms to be rolled out the back. As aircraft grew larger, the U.S. Air Force and Army developed ""low-level extraction"", allowing"
"Optical lift Optical lift is an optical analogue of aerodynamic lift, in which a cambered refractive object with differently shaped top and bottom surfaces experiences a stable transverse lift force when placed in a uniform stream of light. The ability of light to apply pressure to objects is known as radiation pressure, which was first postulated in 1619 and proven in 1900. This is the principle behind the solar sail, which uses light radiation pressure to move through space. A 2010 study by physicist Grover Swartzlander and colleagues of the Rochester Institute of Technology in Rochester, New York shows light"