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Deposition (geology)
Deposition is the geological process in which sediments, soil and rocks are added to a landform or landmass. Wind, ice, water, and gravity transport previously weathered surface material, which, at the loss of enough kinetic energy in the fluid, is deposited, building up layers of sediment. Deposition occurs when the forces responsible for sediment transportation are no longer sufficient to overcome the forces of gravity and friction, creating a resistance to motion; this is known as the null-point hypothesis. Deposition can also refer to the buildup of sediment from organically derived matter or chemical processes. For example, chalk is made up partly of the microscopic calcium carbonate skeletons of marine plankton, the deposition of which has induced chemical processes ( diagenesis) to deposit further calcium carbonate. Similarly, the formation of coal begins with the deposition of organic material, mainly from plants, in anaerobic conditions. Null-point hypothesis Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deposition Erosion
Deposition may refer to: * Deposition (law), taking testimony outside of court * Deposition (politics), the removal of a person of authority from political power * Deposition (university), a widespread initiation ritual for new students practiced from the Middle Ages until the 18th century Art * Deposition from the Cross, the depiction of the removal of Jesus from the cross * ''Deposition'' (Bellini), a 1515–16 painting by Giovanni Bellini and his workshop * ''Deposition of Christ'' (Bronzino), a 1545 oil painting * ''The Deposition'' (Michelangelo), a 1547–55 marble sculpture * ''The Deposition from the Cross'' (Pontormo), a 1528 oil painting * ''Deposition from the Cross'', Volterra (Rosso Fiorentino) * ''The Deposition'' (Raphael), a 1507 oil painting * ''The Deposition'' (Rubens), a 1602 painting by Peter Paul Rubens (previously attributed to van Dyck) now in the Galleria Borghese * ''Deposition'' (Rogier van der Weyden) or ''The Descent from the Cross'', an oil p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas during the late Carboniferous ( Pennsylvanian) and Permian times. Many significant coal deposits are younger than this and originate from the Mesozoic and Cenozoic eras. Coal is used primarily as a fuel. While coal has been known and used for thousands of years, its usage was limited until the Industrial Revolution. With the invention of the steam engine, coal consumption increased. In 2020, coal supplied about a quarter of the world's primary energy and over a third of its electricity. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Akaroa Harbour
Akaroa Harbour, is part of Banks Peninsula in the Canterbury region of New Zealand. The harbour enters from the southern coast of the peninsula, heading in a predominantly northerly direction. It is one of two major inlets in Banks Peninsula, on the coast of Canterbury, New Zealand; the other is Lyttelton Harbour on the northern coast. The name Akaroa is an alternative spelling of Whakaroa, Whangaroa or Wangaloa from the Kāi Tahu dialect of Māori. Whakaroa means "Long Harbour". The harbour was used commercially in the mid-19th century for ship-based and shore-based whaling. Cruise ships occasionally enter the harbour, with the passengers visiting Akaroa. Ōnawe Peninsula is at the head of the harbour, the former site of a Māori pā. Settlements Akaroa Harbour's waterfront has been continually inhabited since the 1840s. Akaroa, Duvauchelle, Takapūneke, Takamatua, Barrys Bay, French Farm and Wainui lie on the shoreline of the harbour. They are connected to the rest of C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flocculation
Flocculation, in the field of chemistry, is a process by which colloidal particles come out of suspension to sediment under the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended, under the form of a stable dispersion (where the internal phase (solid) is dispersed throughout the external phase (fluid) through mechanical agitation) and are not truly dissolved in solution. Coagulation and flocculation are important processes in water treatment with coagulation aimed to destabilize and aggregate particles through chemical interactions between the coagulant and colloids, and flocculation to sediment the destabilized particles by causing their aggregation into floc. Term definition According to the IUPAC definition, flocculation is "a process of contact and adhesion whereby the particles of a dispersion form larger-size clusters". Flocculatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrolyte
An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon dissolving, the substance separates into cations and anions, which disperse uniformly throughout the solvent. Solid-state electrolytes also exist. In medicine and sometimes in chemistry, the term electrolyte refers to the substance that is dissolved. Electrically, such a solution is neutral. If an electric potential is applied to such a solution, the cations of the solution are drawn to the electrode that has an abundance of electrons, while the anions are drawn to the electrode that has a deficit of electrons. The movement of anions and cations in opposite directions within the solution amounts to a current. Some gases, such as hydrogen chloride (HCl), under conditions of high temperature or low pressure can also function as electrolytes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stokes' Law
In 1851, George Gabriel Stokes derived an expression, now known as Stokes' law, for the frictional force – also called drag force – exerted on spherical objects with very small Reynolds numbers in a viscous fluid. Stokes' law is derived by solving the Stokes flow limit for small Reynolds numbers of the Navier–Stokes equations.Batchelor (1967), p. 233. Statement of the law The force of viscosity on a small sphere moving through a viscous fluid is given by: :F_ = 6 \pi \mu R v where: * ''F''d is the frictional force – known as Stokes' drag – acting on the interface between the fluid and the particle * ''μ'' is the dynamic viscosity (some authors use the symbol ''η'') * ''R'' is the radius of the spherical object * ''v'' is the flow velocity relative to the object. In SI units, ''F''d is given in newtons (= kg m s−2), ''μ'' in Pa·s (= kg m−1 s−1), ''R'' in meters, and ''v'' in m/s. Stokes' law makes the following assumptions for the behavior of a partic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stokes Law
In 1851, George Gabriel Stokes derived an expression, now known as Stokes' law, for the frictional force – also called drag force – exerted on spherical objects with very small Reynolds numbers in a viscous fluid. Stokes' law is derived by solving the Stokes flow limit for small Reynolds numbers of the Navier–Stokes equations.Batchelor (1967), p. 233. Statement of the law The force of viscosity on a small sphere moving through a viscous fluid is given by: :F_ = 6 \pi \mu R v where: * ''F''d is the frictional force – known as Stokes' drag – acting on the interface between the fluid and the particle * ''μ'' is the dynamic viscosity (some authors use the symbol ''η'') * ''R'' is the radius of the spherical object * ''v'' is the flow velocity relative to the object. In SI units, ''F''d is given in newtons (= kg m s−2), ''μ'' in Pa·s (= kg m−1 s−1), ''R'' in meters, and ''v'' in m/s. Stokes' law makes the following assumptions for the behavior of a particl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reynolds Number
In fluid mechanics, the Reynolds number () is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces. At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers flows tend to be turbulent. The turbulence results from differences in the fluid's speed and direction, which may sometimes intersect or even move counter to the overall direction of the flow (eddy currents). These eddy currents begin to churn the flow, using up energy in the process, which for liquids increases the chances of cavitation. The Reynolds number has wide applications, ranging from liquid flow in a pipe to the passage of air over an aircraft wing. It is used to predict the transition from laminar to turbulent flow and is used in the scaling of similar but different-sized flow situations, such as between an aircraft model in a wind tunnel and the full-size v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth's Gravity
The gravity of Earth, denoted by , is the net acceleration that is imparted to objects due to the combined effect of gravitation (from mass distribution within Earth) and the centrifugal force (from the Earth's rotation). It is a vector quantity, whose direction coincides with a plumb bob and strength or magnitude is given by the norm g=\, \mathit\, . In SI units this acceleration is expressed in metres per second squared (in symbols, m/ s2 or m·s−2) or equivalently in newtons per kilogram (N/kg or N·kg−1). Near Earth's surface, the gravity acceleration is approximately , which means that, ignoring the effects of air resistance, the speed of an object falling freely will increase by about per second every second. This quantity is sometimes referred to informally as ''little '' (in contrast, the gravitational constant is referred to as ''big ''). The precise strength of Earth's gravity varies depending on location. The nominal "average" value at Earth's surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bohai Bay
Bohai Bay () is one of the three major bays of the Bohai Sea, the northwestern and innermost gulf of the Yellow Sea. It is bounded by the coastlines of eastern Hebei province (Tangshan and Cangzhou), Tianjin municipality and northern Shandong province ( Binzhou and Dongying) south of the Daqing River estuary (which is an old mouth of Luan River in Laoting County) and north of the Yellow River estuary. It is the most southerly water in the northern hemisphere where sea ice can form. The Bohai Bay is the drainage destination of the Hai River and 15 other rivers. Due to these rivers' muddy runoff, the bay used to be a highly silty water body, but extensive damming of the various river systems has greatly diminished siltage. Nevertheless, the Bohai Bay in effect concentrates the runoff of the whole eastern North China Plain, and the Bay is an intensely polluted body of water. Reduced silt deposition and sea level rise are causing problems with sea encroachment in some coas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Wash
The Wash is a rectangular bay and multiple estuary at the north-west corner of East Anglia on the East coast of England, where Norfolk meets Lincolnshire and both border the North Sea. One of Britain's broadest estuaries, it is fed by the rivers Witham, Welland, Nene and Great Ouse. It is a biological Site of Special Scientific Interest. It is also a Nature Conservation Review site, Grade I, a National Nature Reserve, a Ramsar site, a Special Area of Conservation and a Special Protection Area. It is in the Norfolk Coast Area of Outstanding Natural Beauty and part of it is the Snettisham Royal Society for the Protection of Birds nature reserve. Geography The Wash makes a large indentation in the coastline of Eastern England that separates the curved coast of East Anglia from Lincolnshire. It is a large bay with three roughly straight sides meeting at right angles, each about in length. The eastern coast of the Wash is entirely within Norfolk, and extends from a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Akaroa
Akaroa is a small town on Banks Peninsula in the Canterbury Region of the South Island of New Zealand, situated within a harbour of the same name. The name Akaroa is Kāi Tahu Māori for "Long Harbour", which would be spelled in standard Māori. The area was also named ''Port Louis-Philippe'' by French settlers after the reigning French king Louis Philippe I. The town is by road from Christchurch and is the terminus of State Highway 75. It is set on a sheltered harbour and is overlooked and surrounded by the remnants of a miocene volcano. Akaroa is entirely dependent upon rainfall on the hills. Akaroa is a popular resort town. Many Hector's dolphins may be found within the harbour, and 'swim with the dolphins' boat tours are a major tourist attraction. Ōnuku marae, a (tribal meeting ground) of Ngāi Tahu and its Ōnuku Rūnanga branch, is located in Akaroa. It includes the Karaweko (meeting house). History In 1830, the Māori settlement at Takapūneke, just ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
