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Water Eductor
{{Short description, Type of pump used in archeology A water eductor or water dredge is an eductor-jet pump-based tool used by underwater archaeologists to remove sediments from an underwater archaeological site. Airlifts may be used for the same purpose. It consists of a large bore straight tube to which is attached a hose pipe through which clean water is pumped. The Bernoulli effect from the flow of pumped water causes suction at the mouth of the dredge. Water and sediment are sucked from the excavation site and released from the far end of the tube. The tube can be made of any rigid material such as steel or plastic. The diameter of the tube depends on the power available from the pump and whether delicate work is required. In the hands of a trained archaeologist, the water dredge performs the same function as a wheelbarrow on land. It is used to carry away sediments, not to dig holes. The archaeologist dislodges the material using a trowel, brush or by making a fanning ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eductor-jet Pump
A vacuum ejector, or simply ejector, or aspirator, is a type of vacuum pump, which produces vacuum by means of the Venturi effect. In an ejector, a working fluid (liquid or gaseous) flows through a jet nozzle into a tube that first narrows and then expands in cross-sectional area. The fluid leaving the jet is flowing at a high velocity which due to Bernoulli's principle results in it having low pressure, thus generating a vacuum. The outer tube then narrows into a mixing section where the high velocity working fluid mixes with the fluid that is drawn in by the vacuum, imparting enough velocity for it to be ejected, the tube then typically expands in order to decrease the velocity of the ejected stream, allowing the pressure to smoothly increase to the external pressure. The strength of the vacuum produced depends on the velocity and shape of the fluid jet and the shape of the constriction and mixing sections, but if a liquid is used as the working fluid, the strength of the vac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artifact (archaeology)
An artifact or artefact (British English) is a general term for an item made or given shape by humans, such as a tool or a work of art, especially an object of archaeological interest. In archaeology, the word has become a term of particular nuance; it is defined as an object recovered by archaeological endeavor, including cultural artifacts (of archaeological culture, cultural interest). "Artifact" is the general term used in archaeology, while in museums the equivalent general term is normally "object", and in art history perhaps artwork or a more specific term such as "carving". The same item may be called all or any of these in different contexts, and more specific terms will be used when talking about individual objects, or groups of similar ones. Artifacts exist in many different forms and can sometimes be confused with Biofact (archaeology), ecofacts and Feature (archaeology), features; all three of these can sometimes be found together at archaeological sites. They can a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maritime Archaeology
Maritime archaeology (also known as marine archaeology) is a discipline within archaeology as a whole that specifically studies human interaction with the sea, lakes and rivers through the study of associated physical remains, be they vessels, shore-side facilities, port-related structures, cargoes, human remains (archaeology), human remains and submerged landscapes. A specialty within maritime archaeology is nautical archaeology, which studies ship construction and use. As with archaeology as a whole, maritime archaeology can be practised within the historical, industrial, or prehistoric periods. An associated discipline, and again one that lies within archaeology itself, is underwater archaeology, which studies the past through any submerged remains be they of maritime interest or not. An example from the prehistoric era would be the remains of submerged settlements or deposits now lying under water despite having been dry land when sea levels were lower. The study of submerge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Geographic Magazine
''National Geographic'' (formerly ''The National Geographic Magazine'', sometimes branded as ''Nat Geo'') is an American monthly magazine published by National Geographic Partners. The magazine was founded in 1888 as a scholarly journal, nine months after the establishment of the society, but is now a popular magazine. In 1905, it began including pictures, a style for which it became well known. Its first color photos appeared in the 1910s. During the Cold War, the magazine committed itself to present a balanced view of the physical and human geography of countries beyond the Iron Curtain. Later, the magazine became outspoken on environmental issues. Until 2015, the magazine was completely owned and managed by the National Geographic Society. Since 2015, controlling interest has been held by National Geographic Partners. Topics of features generally concern geography, history, nature, science, and world culture. The magazine is well known for its distinctive appearance: a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Lift
A gas lift or bubble pump is a type of pump that can raise fluid between elevations by introducing gas bubbles into a vertical outlet tube; as the bubbles rise within the tube they cause a drop in the hydrostatic pressure behind them, causing the fluid to be pulled up. Gas lifts are commonly used as artificial lifts for water or oil, using compressed air or water vapor. Gas lifts have been used for a variety of applications: *Coffee percolators and electric drip coffeemakers use vaporized water to lift hot water * Airlift pumps use compressed air to lift water * Pulser pumps use a subterranean air chamber to lift underground water * Suction dredges use a variety of the gas lift called an '' airlift pump'' to vacuum mud, sand and debris * Mist lifts use vaporized water to draw seawater in ocean thermal energy conversion systems Petroleum industry uses In the United States, gas lift is used in 10% of the oil wells that have insufficient reservoir pressure to produce the wel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aspirator (pump)
A vacuum ejector, or simply ejector, or aspirator, is a type of vacuum pump, which produces vacuum by means of the Venturi effect. In an ejector, a working fluid (liquid or gaseous) flows through a jet nozzle into a tube that first narrows and then expands in cross-sectional area. The fluid leaving the jet is flowing at a high velocity which due to Bernoulli's principle results in it having low pressure, thus generating a vacuum. The outer tube then narrows into a mixing section where the high velocity working fluid mixes with the fluid that is drawn in by the vacuum, imparting enough velocity for it to be ejected, the tube then typically expands in order to decrease the velocity of the ejected stream, allowing the pressure to smoothly increase to the external pressure. The strength of the vacuum produced depends on the velocity and shape of the fluid jet and the shape of the constriction and mixing sections, but if a liquid is used as the working fluid, the strength of the va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airlift Pump
An airlift pump is a pump that has low suction and moderate discharge of liquid and entrained solids. The pump injects compressed air at the bottom of the discharge pipe which is immersed in the liquid. The compressed air mixes with the liquid causing the air-water mixture to be less dense than the rest of the liquid around it and therefore is displaced upwards through the discharge pipe by the surrounding liquid of higher density. Solids may be entrained in the flow and if small enough to fit through the pipe, will be discharged with the rest of the flow at a shallower depth or above the surface. Airlift pumps are widely used in aquaculture to pump, circulate and aerate water in closed, recirculating systems and ponds. Other applications include dredging, underwater archaeology, salvage operations and collection of Biological specimen, scientific specimens. Principle The only energy required is provided by compressed air. This air is usually compressed by a gas compressor, compr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Venturi Tube
The Venturi effect is the reduction in fluid pressure that results when a moving fluid speeds up as it flows from one section of a pipe to a smaller section. The Venturi effect is named after its discoverer, the Italian physicist Giovanni Battista Venturi, and was first published in 1797. The effect has various engineering applications, as the reduction in pressure inside the constriction can be used both for measuring the fluid flow and for moving other fluids (e.g. in a vacuum ejector). Background In inviscid flow, inviscid fluid dynamics, an incompressible fluid's velocity must ''increase'' as it passes through a constriction in accord with the Continuity equation#Fluid dynamics, principle of mass continuity, while its static pressure must ''decrease'' in accord with the principle of Mechanical energy#Conservation of mechanical energy, conservation of mechanical energy (Bernoulli's principle) or according to the Euler equations (fluid dynamics), Euler equations. Thus, any ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wet Scrubber
The term wet scrubber describes a variety of devices that remove pollutants from a Industrial furnace, furnace flue gas or from other gas streams. In a wet scrubber, the polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the liquid, by forcing it through a pool of liquid, or by some other contact method, so as to remove the pollutants. Wet scrubbers capture relatively small dust wiktionary:Particle, particles with the wet scrubber's large liquid droplets. In most wet scrubbing systems, droplets produced are generally larger than 50 micrometres (in the 150 to 500 micrometres range). As a point of reference, human hair ranges in diameter from 50 to 100 micrometres. The Particle size distribution, size distribution of particles to be collected is source specific. For example, particles produced by mechanical means (crushing or grinding) tend to be large (above 10 micrometres); whereas, particles produced from combustion or a chemical reaction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratigraphy
Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostratigraphy (lithologic stratigraphy), biostratigraphy (biologic stratigraphy), and chronostratigraphy (stratigraphy by age). Historical development Catholic priest Nicholas Steno established the theoretical basis for stratigraphy when he introduced the law of superposition, the principle of original horizontality and the principle of lateral continuity in a 1669 work on the fossilization of organic remains in layers of sediment. The first practical large-scale application of stratigraphy was by William Smith in the 1790s and early 19th century. Known as the "Father of English geology", Smith recognized the significance of strata or rock layering and the importance of fossil markers for correlating strata; he created the first geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Underwater Archaeology
Underwater archaeology is archaeology practiced underwater. As with all other branches of archaeology, it evolved from its roots in pre-history and in the classical era to include sites from the historical and industrial eras. Its acceptance has been a relatively late development due to the difficulties of accessing and working underwater sites, and because the application of archaeology to underwater sites initially emerged from the skills and tools developed by shipwreck salvagers. As a result, underwater archaeology initially struggled to establish itself as actual archaeological research. This changed when universities began teaching the subject and a theoretical and practical base for the sub-discipline was firmly established in the late 1980s. Underwater archaeology now has a number of branches including, maritime archaeology: the scientifically based study of past human life, behaviors and cultures and their activities in, on, around and (lately) under the sea, estuarie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feature (archaeology)
In archaeological excavation, a feature is a collection of one or more contexts representing some human non-portable activity, such as a hearth or wall. Features serve as an indication that the area in which they are found has been interfered with in the past, usually by humans. Features are distinguished from artifacts in that they cannot be separated from their location without changing their form. Artifacts are portable, while features are non-portable. Artifacts and features can both be made from any available material, with the primary distinction being portability. Features and artifacts differ from ecofacts. Ecofacts are natural remains, such as plants and animals. Types Features are categorized by the time period, as either historic or prehistoric. Prehistoric archaeology refers to the time in history before human life was recorded or documented, while historic archaeology refers to the time period where there was a documented human past. In relation to site stra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
