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Ullage
Ullage or headspace is the unfilled space in a container, particularly with a liquid. Etymology The word ''ullage'' comes from the Latin word ''oculus'', used by the Romans to refer to a barrel cork hole. This word was, in turn, taken in medieval French as ''oeil'', from which a verb ''ouiller'' was created, meaning to fill a barrel to full capacity. Around 1300, the word ''ouillage'' was created by the Normans to refer to the amount of liquid needed to fill a barrel to capacity. Alcoholic beverages In winemaking, ''ullage'' came to refer to any amount by which a barrel is unfilled, perhaps because some of the contents have been used. It is also applied to the unfilled air space at the top of a bottle of wine, which in this case is essential to allow for expansion of the contents as the temperature changes. By further extension, in brewing and beer retail, ''ullage'' is the residue of beer left in a barrel that has been emptied. When calculating tax returns and the like, licens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ullage Motor
Ullage motors (also known as ullage engines or ullage rockets) are relatively small, independently fueled rocket engines that may be fired prior to main engine ignition, when the vehicle is in a zero-g situation. The resulting acceleration causes liquid in the rocket's main tanks to settle towards the aft end, ensuring uninterrupted flow to the fuel and oxidizer pumps. Description Cryogenic-liquid-fueled rockets keep their propellants in insulated tanks. These tanks are never completely filled to allow for expansion. In weightlessness, micro-gravity conditions the cryogenic liquids are without a free surface, and exist in a slushy state between solid, liquid, and gas. In this mixed state, ullage gases may be sucked into the engines, which is undesirable, as it displaces useful propellant, reduces efficiency, and may damage the engines. Small rocket engines, called "ullage motors", are sometimes used to settle the propellant before main engine ignition to allow the formation of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Control System
A reaction control system (RCS) is a spacecraft system that uses Thrusters (spacecraft), thrusters to provide Spacecraft attitude control, attitude control and translation (physics), translation. Alternatively, reaction wheels can be used for attitude control, rather than RCS. Use of diverted engine thrust to provide stable attitude control of a V/STOL, short-or-vertical takeoff and landing aircraft below conventional winged flight speeds, such as with the Hawker Siddeley Harrier#Controls and handling, Harrier "jump jet", may also be referred to as a reaction control system. Reaction control systems are capable of providing small amounts of thrust in any desired direction or combination of directions. An RCS is also capable of providing torque to allow control of rotation (aircraft principal axes, roll, pitch, and yaw). Reaction control systems often use combinations of large and small (vernier thruster, vernier) thrusters, to allow different levels of response. Uses Spacecr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Propellant Rocket
A liquid-propellant rocket or liquid rocket uses a rocket engine burning liquid propellants. (Alternate approaches use gaseous or solid propellants.) Liquids are desirable propellants because they have reasonably high density and their combustion products have high specific impulse (''I''sp). This allows the volume of the propellant tanks to be relatively low. Types Liquid rockets can be monopropellant rockets using a single type of propellant, or bipropellant rockets using two types of propellant. Tripropellant rockets using three types of propellant are rare. Liquid oxidizer propellants are also used in hybrid rockets, with some of the advantages of a solid rocket. Bipropellant liquid rockets use a liquid fuel such as liquid hydrogen or RP-1, and a liquid oxidizer such as liquid oxygen. The engine may be a cryogenic rocket engine, where the fuel and oxidizer, such as hydrogen and oxygen, are gases which have been liquefied at very low temperatures. Most designs of liquid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cereal
A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize ( Corn). Edible grains from other plant families, such as amaranth, buckwheat and quinoa, are pseudocereals. Most cereals are annuals, producing one crop from each planting, though rice is sometimes grown as a perennial. Winter varieties are hardy enough to be planted in the autumn, becoming dormant in the winter, and harvested in spring or early summer; spring varieties are planted in spring and harvested in late summer. The term cereal is derived from the name of the Roman goddess of grain crops and fertility, Ceres. Cereals were domesticated in the Neolithic around 8,000 years ago. Wheat and barley were domesticated in the Fertile Crescent; rice and some millets were domesticated in East Asia, while sorghum and other millets were domesticated in West Africa. Maize was domesticat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Surface Effect
The free surface effect is a mechanism which can cause a watercraft to become unstable and capsize. It refers to the tendency of liquids — and of unbound aggregates of small solid objects, like seeds, gravel, or crushed ore, whose behavior approximates that of liquids — to move in response to changes in the attitude of a craft's cargo holds, decks, or liquid tanks in reaction to operator-induced motions (or sea states caused by waves and wind acting upon the craft). When referring to the free surface effect, the condition of a tank that is not full is described as a "slack tank", while a full tank is "pressed up". Stability and equilibrium In a normally loaded vessel any rolling from perpendicular is countered by a righting moment generated from the increased volume of water displaced by the hull on the lowered side. This assumes the center of gravity of the vessel is relatively constant. If a moving mass inside the vessel moves in the direction of the roll, this counters t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sailing
Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the ''water'' (sailing ship, sailboat, raft, Windsurfing, windsurfer, or Kitesurfing, kitesurfer), on ''ice'' (iceboat) or on ''land'' (Land sailing, land yacht) over a chosen Course (navigation), course, which is often part of a larger plan of navigation. From prehistory until the second half of the 19th century, sailing craft were the primary means of maritime trade and transportation; exploration across the seas and oceans was reliant on sail for anything other than the shortest distances. Naval power in this period used sail to varying degrees depending on the current technology, culminating in the gun-armed sailing warships of the Age of Sail. Sail was slowly replaced by steam as the method of propulsion for ships over the latter part of the 19th century – seeing a gradual improvement in the technology of steam through a number of developmental steps. Steam allowed schedul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulk Cargo
Bulk cargo is Product (business), product cargo that is transported packaging, unpackaged in large quantities. Description Bulk cargo refers to material in either liquid or granular, particulate (as a mass of relatively small solids) form, such as petroleum/crude oil, cereal, grain, coal, or gravel. This cargo is usually dropped or poured, with a spout or shovel bucket, into a bulk carrier Hold (ship), ship's hold, Railroad car#Freight cars, railroad car/railway wagon, or tanker truck/Trailer (vehicle), trailer/semi-trailer body. Smaller quantities can be boxed (or drum (container), drummed) and palletised; cargo packaged in this manner is referred to as breakbulk cargo. Bulk cargo is classified as liquid, wet or dry goods, dry. Baltic Exchange, The Baltic Exchange is based in London and provides a range of indices benchmarking the cost of moving bulk commodities, dry and wet, along popular routes around the seas. Some of these indices are also used to settle Freight Future ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship Stability
Ship stability is an area of naval architecture and ship design that deals with how a ship behaves at sea, both in still water and in waves, whether intact or damaged. Stability calculations focus on center of mass#center of gravity, centers of gravity, buoyancy, centers of buoyancy, the metacenters of vessels, and on how these interact. History Ship stability, as it pertains to naval architecture, has been taken into account for hundreds of years. Historically, ship stability calculations relied on rule of thumb calculations, often tied to a specific system of measurement. Some of these very old equations continue to be used in naval architecture books today. However, the advent of calculus-based methods of determining stability, particularly Pierre Bouguer's introduction of the concept of the metacenter in the 1740s ship model basin, allow much more complex analysis. Master shipbuilders of the past used a system of adaptive and variant design. Ships were often copied from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vapor
In physics, a vapor (American English) or vapour (Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature,R. H. Petrucci, W. S. Harwood, and F. G. Herring, ''General Chemistry'', Prentice-Hall, 8th ed. 2002, p. 483–86. which means that the vapor can be condensation, condensed to a liquid by increasing the pressure on it without reducing the temperature of the vapor. A vapor is different from an aerosol. An aerosol is a suspension of tiny particles of liquid, solid, or both within a gas. For example, water has a critical temperature of , which is the highest temperature at which liquid water can exist at any pressure. In the Earth's atmosphere, atmosphere at ordinary temperatures gaseous water (known as water vapor) will condense into a liquid if its partial pressure is increased sufficiently. A vapor may co-exist with a liquid (or a solid). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relief Valve
A relief valve or pressure relief valve (PRV) is a type of safety valve used to control or limit the pressure in a system; excessive pressure might otherwise build up and create a process upset, instrument or equipment failure, explosion, or fire. Pressure relief Excess pressure is relieved by allowing the pressurized fluid to flow from an auxiliary passage out of the system. The relief valve is designed or set to open at a predetermined set pressure to protect pressure vessels and other equipment from being subjected to pressures that exceed their design limits. When the set pressure is exceeded, the relief valve becomes the " path of least resistance" as the valve is forced open and a portion of the fluid is diverted through the auxiliary route. In systems containing flammable fluids, the diverted fluid (liquid, gas or liquid-gas mixture) is either recaptured by a low pressure, high-flow vapor recovery system or is routed through a piping system known as a ''flare header'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Code Of Federal Regulations
In the law of the United States, the ''Code of Federal Regulations'' (''CFR'') is the codification of the general and permanent regulatory law, regulations promulgated by the executive departments and agencies of the federal government of the United States. The CFR is divided into 50 titles that represent broad areas subject to federal regulation. The CFR annual edition is published as a special issue of the ''Federal Register'' by the Office of the Federal Register (part of the National Archives and Records Administration) and the Government Publishing Office. In addition to this annual edition, the CFR is published online on the Electronic CFR (eCFR) website, which is updated daily. Background Congress frequently delegates authority to an executive branch agency to issue regulations to govern some sphere. These statutes are called "authorizing statute" or "enabling statute" (or "authorizing legislation"). Authorizing statutes typically have two parts: (1) a substantive sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Maritime Organization
The International Maritime Organization (IMO; ; ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations responsible for regulating maritime transport. The IMO was established following agreement at a UN conference held in Geneva in 1948 and the IMO came into existence ten years later, meeting for the first time on 17 March 1958. Headquartered in London, United Kingdom, the IMO, in 2024, has 176 Member States and three Associate Members. The IMO's primary purpose is to develop and maintain a comprehensive regulatory framework for shipping and its remit today includes maritime safety, environmental concerns, and Admiralty law, legal matters, among other issues. IMO is governed by an assembly of members which meets every two years. Its finance and organization is administered by a council of 40 members elected from the assembly. The work of IMO is conducted through five committees and these are supported by technical subcommittees. Other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
