1.
Colloid
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A colloid, in chemistry, is a mixture in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance. Sometimes the dispersed substance alone is called the colloid, the colloidal suspension refers unambiguously to the overall mixture. Unlike a solution, whose solute and solvent constitute only one phase, a colloid has a dispersed phase, to qualify as a colloid, the mixture must be one that does not settle or would take a very long time to settle appreciably. The dispersed-phase particles have a diameter between approximately 1 and 1000 nanometers, such particles are normally easily visible in an optical microscope, although at the smaller size range, an ultramicroscope or an electron microscope may be required. Homogeneous mixtures with a phase in this size range may be called colloidal aerosols, colloidal emulsions, colloidal foams, colloidal dispersions. The dispersed-phase particles or droplets are affected largely by the surface chemistry present in the colloid, some colloids are translucent because of the Tyndall effect, which is the scattering of light by particles in the colloid. Other colloids may be opaque or have a slight color, Colloidal suspensions are the subject of interface and colloid science. This field of study was introduced in 1861 by Scottish scientist Thomas Graham, because of the size exclusion, the colloidal particles are unable to pass through the pores of an ultrafiltration membrane with a size smaller than their own dimension. The smaller the size of the pore of the ultrafiltration membrane, the measured value of the concentration of a truly dissolved species will thus depend on the experimental conditions applied to separate it from the colloidal particles also dispersed in the liquid. This is particularly important for solubility studies of readily hydrolyzed species such as Al, Eu, Am, Cm, the colloid particles are attracted toward water. They are also called reversible sols, hydrophobic colloids, These are opposite in nature to hydrophilic colloids. The colloid particles are repelled by water and they are also called irreversible sols. In some cases, a colloid suspension can be considered a homogeneous mixture and this is because the distinction between dissolved and particulate matter can be sometimes a matter of approach, which affects whether or not it is homogeneous or heterogeneous. The following forces play an important role in the interaction of particles, Excluded volume repulsion. Electrostatic interaction, Colloidal particles often carry a charge and therefore attract or repel each other. The charge of both the continuous and the phase, as well as the mobility of the phases are factors affecting this interaction. Van der Waals forces, This is due to interaction between two dipoles that are permanent or induced. Even if the particles do not have a permanent dipole, fluctuations of the electron density gives rise to a dipole in a particle
2.
Gel
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A gel is a solid jelly-like material that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, by weight, gels are mostly liquid, yet they behave like solids due to a three-dimensional cross-linked network within the liquid. It is the crosslinking within the fluid that gives a gel its structure, in this way gels are a dispersion of molecules of a liquid within a solid in which the solid is the continuous phase and the liquid is the discontinuous phase. The word gel was coined by 19th-century Scottish chemist Thomas Graham by clipping from gelatine, gels consist of a solid three-dimensional network that spans the volume of a liquid medium and ensnares it through surface tension effects. This internal network structure may result from physical bonds or chemical bonds, virtually any fluid can be used as an extender including water, oil, and air. Both by weight and volume, gels are mostly fluid in composition, edible jelly is a common example of a hydrogel and has approximately the density of water. Polyionic polymers are polymers with a functional group. The ionic charges prevent the formation of tightly coiled polymer chains and this allows them to contribute more to viscosity in their stretched state, because the stretched-out polymer takes up more space. A hydrogel is a network of polymer chains that are hydrophilic, hydrogels are highly absorbent natural or synthetic polymeric networks. Hydrogels also possess a degree of flexibility very similar to tissue, due to their significant water content. The first appearance of the term hydrogel in the literature was in 1894, common uses for hydrogels include, Scaffolds in tissue engineering. When used as scaffolds, hydrogels may contain human cells to repair tissue and they mimic 3D microenvironment of cells. Hydrogel-coated wells have been used for cell culture Environmentally sensitive hydrogels and these hydrogels have the ability to sense changes of pH, temperature, or the concentration of metabolite and release their load as result of such a change. Wound gels are excellent for helping to create or maintain a moist environment, reservoirs in topical drug delivery, particularly ionic drugs, delivered by iontophoresis. Natural hydrogel materials are being investigated for tissue engineering, these materials include agarose, methylcellulose, hyaluronan, an organogel is a non-crystalline, non-glassy thermoreversible solid material composed of a liquid organic phase entrapped in a three-dimensionally cross-linked network. The liquid can be, for example, a solvent, mineral oil. The solubility and particle dimensions of the structurant are important characteristics for the elastic properties, often, these systems are based on self-assembly of the structurant molecules. Organogels have potential for use in a number of applications, such as in pharmaceuticals, cosmetics, art conservation, a xerogel /ˈzɪəroʊˌdʒɛl/ is a solid formed from a gel by drying with unhindered shrinkage
3.
Granular material
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A granular material is a conglomeration of discrete solid, macroscopic particles characterized by a loss of energy whenever the particles interact. The constituents that compose granular material must be large enough such that they are not subject to thermal motion fluctuations, thus, the lower size limit for grains in granular material is about 1 µm. Some examples of materials are snow, nuts, coal, sand, rice, coffee, corn flakes, fertilizer. Powders are a class of granular material due to their small particle size. Granular materials are important in applications as diverse as pharmaceutical industry, agriculture. Research into granular materials is thus directly applicable and goes back at least to Charles-Augustin de Coulomb, according to material scientist Patrick Richard, Granular materials are ubiquitous in nature and are the second-most manipulated material in industry. In some sense, granular materials do not constitute a phase of matter but have characteristics reminiscent of solids, liquids. However, in each of these states granular materials also exhibit properties which are unique, Granular materials also exhibit a wide range of pattern forming behaviors when excited. As such granular materials under excitation can be thought of as an example of a complex system, when the average energy of the individual grains is low and the grains are fairly stationary relative to each other, the granular material acts like a solid. In general, stress in a solid is not distributed uniformly but is conducted away along so-called force chains which are networks of grains resting on one another. Between these chains are regions of low stress whose grains are shielded for the effects of the grains above by vaulting and arching, if the granular material is driven harder such that contacts between the grains become highly infrequent, the material enters a gaseous state. Correspondingly, one can define a granular temperature equal to the mean square of grain velocity fluctuations that is analogous to thermodynamic temperature. Unlike conventional gases, granular materials will tend to cluster and clump due to the nature of the collisions between grains and this clustering has some interesting consequences. This effect, known as the granular Maxwells demon, does not violate any thermodynamics principles since energy is constantly being lost from the system in the process. Granular systems are known to exhibit jamming and undergo a transition which is thought of as a thermodynamic phase transition to a jammed state. The Lubachevsky-Stillinger algorithm of jamming allows one to produce simulated jammed granular configurations, excited granular matter is a rich pattern-forming system. Some of the pattern-forming behaviours seen in granular materials are, The un-mixing or segregation of unlike grains under vibration, Some larger materials get stuck while going down the circle and therefore stay on the top. The formation of surface patterns in vibrated granular layers and these patterns include but are not limited to stripes, squares and hexagons
4.
Sand
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Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. It is defined by size, being finer than gravel and coarser than silt, Sand can also refer to a textural class of soil or soil type, i. e. a soil containing more than 85% sand-sized particles by mass. The second most common type of sand is calcium carbonate, for example aragonite, for example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean. Sand is a non renewable resource over human timescales, and sand suitable for making concrete is in high demand, in terms of particle size as used by geologists, sand particles range in diameter from 0.0625 mm to 2 mm. An individual particle in this size is termed a sand grain. Sand grains are between gravel and silt, a 1953 engineering standard published by the American Association of State Highway and Transportation Officials set the minimum sand size at 0.074 mm. A1938 specification of the United States Department of Agriculture was 0.05 mm. Sand feels gritty when rubbed between the fingers. ISO14688 grades sands as fine, medium and coarse with ranges 0.063 mm to 0.2 mm to 0.63 mm to 2.0 mm. In the United States, sand is commonly divided into five sub-categories based on size, very fine sand, fine sand, medium sand, coarse sand, and very coarse sand. These sizes are based on the Krumbein phi scale, where size in Φ = -log2D, on this scale, for sand the value of Φ varies from −1 to +4, with the divisions between sub-categories at whole numbers. The composition of sand is highly variable, depending on the local rock sources. The gypsum sand dunes of the White Sands National Monument in New Mexico are famous for their bright, arkose is a sand or sandstone with considerable feldspar content, derived from weathering and erosion of a granitic rock outcrop. Some sands contain magnetite, chlorite, glauconite or gypsum, Sands rich in magnetite are dark to black in color, as are sands derived from volcanic basalts and obsidian. Chlorite-glauconite bearing sands are typically green in color, as are sands derived from basaltic with a high olivine content, many sands, especially those found extensively in Southern Europe, have iron impurities within the quartz crystals of the sand, giving a deep yellow color. Sand deposits in some areas contain garnets and other resistant minerals, the study of individual grains can reveal much historical information as to the origin and kind of transport of the grain. Quartz sand that is weathered from granite or gneiss quartz crystals will be angular. It is called grus in geology or sharp sand in the trade where it is preferred for concrete. Sand that is transported long distances by water or wind will be rounded, people who collect sand as a hobby are known as arenophiles
5.
Silt
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Silt is granular material of a size between sand and clay, whose mineral origin is quartz and feldspar. Silt may occur as a soil or as sediment mixed in suspension with water in a body of such as a river. It may also exist as soil deposited at the bottom of a water body, Silt has a moderate specific area with a typically non-sticky, plastic feel. Silt usually has a floury feel when dry, and a slippery feel when wet, Silt can be visually observed with a hand lens. Silt is created by a variety of physical processes capable of splitting the generally sand-sized quartz crystals of primary rocks by exploiting deficiencies in their lattice and these involve chemical weathering of rock and regolith, and a number of physical weathering processes such as frost shattering and haloclasty. The main process is abrasion through transport, including fluvial comminution, aeolian attrition and it is in semi-arid environments that substantial quantities of silt are produced. Silt is sometimes known as rock flour or stone dust, especially produced by glacial action. Mineralogically, silt is composed mainly of quartz and feldspar, sedimentary rock composed mainly of silt is known as siltstone. Liquefaction created by an earthquake is silt suspended in water that is hydrodynamically forced up from below ground level. In the Udden–Wentworth scale, silt particles range between 0.0039 and 0.0625 mm, larger than clay but smaller than sand particles, ISO14688 grades silts between 0.002 mm and 0.063 mm. In actuality, silt is chemically distinct from clay, and unlike clay, grains of silt are approximately the size in all dimensions, furthermore. Clays are formed from thin plate-shaped particles held together by electrostatic forces, according to the U. S. Department of Agriculture Soil Texture Classification system, the sand-silt distinction is made at the 0.05 mm particle size. The USDA system has been adopted by the Food and Agriculture Organization, in the Unified Soil Classification System and the AASHTO Soil Classification system, the sand-silt distinction is made at the 0.075 mm particle size. Silts and clays are distinguished mechanically by their plasticity, Silt is easily transported in water or other liquid and is fine enough to be carried long distances by air in the form of dust. Thick deposits of silty material resulting from deposition by aeolian processes are called loess. Silt and clay contribute to turbidity in water, Silt is transported by streams or by water currents in the ocean. When silt appears as a pollutant in water the phenomenon is known as siltation, Silt, deposited by annual floods along the Nile River, created the rich, fertile soil that sustained the Ancient Egyptian civilization. In south east Bangladesh, in the Noakhali district, cross dams were built in the 1960s whereby silt gradually started forming new land called chars, the district of Noakhali has gained more than 28 square miles of land in the past 50 years
6.
Clay
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Clay is a fine-grained natural rock or soil material that combines one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure. Clays are plastic due to water content and become hard, brittle. Depending on the content in which it is found, clay can appear in various colours from white to dull grey or brown to deep orange-red. Although many naturally occurring deposits include both silts and clay, clays are distinguished from other fine-grained soils by differences in size, silts, which are fine-grained soils that do not include clay minerals, tend to have larger particle sizes than clays. There is, however, some overlap in size and other physical properties. The distinction between silt and clay varies by discipline, geologists and soil scientists usually consider the separation to occur at a particle size of 2 µm, sedimentologists often use 4–5 μm, and colloid chemists use 1 μm. Geotechnical engineers distinguish between silts and clays based on the plasticity properties of the soil, as measured by the soils Atterberg limits, ISO14688 grades clay particles as being smaller than 2 μm and silt particles as being larger. These solvents, usually acidic, migrate through the rock after leaching through upper weathered layers. In addition to the process, some clay minerals are formed through hydrothermal activity. There are two types of deposits, primary and secondary. Primary clays form as residual deposits in soil and remain at the site of formation, secondary clays are clays that have been transported from their original location by water erosion and deposited in a new sedimentary deposit. Clay deposits are associated with very low energy depositional environments such as large lakes. Depending on the source, there are three or four main groups of clays, kaolinite, montmorillonite-smectite, illite, and chlorite. Chlorites are not always considered to be a clay, sometimes being classified as a group within the phyllosilicates. There are approximately 30 different types of clays in these categories. Varve is clay with visible annual layers, which are formed by deposition of those layers and are marked by differences in erosion. This type of deposit is common in glacial lakes
7.
Water
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Water is a transparent and nearly colorless chemical substance that is the main constituent of Earths streams, lakes, and oceans, and the fluids of most living organisms. Its chemical formula is H2O, meaning that its molecule contains one oxygen, Water strictly refers to the liquid state of that substance, that prevails at standard ambient temperature and pressure, but it often refers also to its solid state or its gaseous state. It also occurs in nature as snow, glaciers, ice packs and icebergs, clouds, fog, dew, aquifers, Water covers 71% of the Earths surface. It is vital for all forms of life. Only 2. 5% of this water is freshwater, and 98. 8% of that water is in ice and groundwater. Less than 0. 3% of all freshwater is in rivers, lakes, and the atmosphere, a greater quantity of water is found in the earths interior. Water on Earth moves continually through the cycle of evaporation and transpiration, condensation, precipitation. Evaporation and transpiration contribute to the precipitation over land, large amounts of water are also chemically combined or adsorbed in hydrated minerals. Safe drinking water is essential to humans and other even though it provides no calories or organic nutrients. There is a correlation between access to safe water and gross domestic product per capita. However, some observers have estimated that by 2025 more than half of the population will be facing water-based vulnerability. A report, issued in November 2009, suggests that by 2030, in developing regions of the world. Water plays an important role in the world economy, approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a source of food for many parts of the world. Much of long-distance trade of commodities and manufactured products is transported by boats through seas, rivers, lakes, large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a variety of chemical substances, as such it is widely used in industrial processes. Water is also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, Water is a liquid at the temperatures and pressures that are most adequate for life. Specifically, at atmospheric pressure of 1 bar, water is a liquid between the temperatures of 273.15 K and 373.15 K
8.
Artesian aquifer
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See Great Artesian Basin for the water source in Australia. An artesian aquifer is a confined aquifer containing groundwater under positive pressure and this causes the water level in a well to rise to a point where hydrostatic equilibrium has been reached. A well drilled into such an aquifer is called an artesian well, if water reaches the ground surface under the natural pressure of the aquifer, the well is called a flowing artesian well. An aquifer is a layer of porous and permeable material such as sand and gravel, limestone, or sandstone. An artesian aquifer is confined between impermeable rocks or clay which causes this positive pressure, not all the aquifers are artesian, because the water table must reach the surface. The recharging of aquifers happens when the table at its recharge zone is at a higher elevation than the head of the well. Fossil water aquifers can also be if they are under sufficient pressure from the surrounding rocks. This is similar to how many newly tapped oil wells are pressurized, Artesian wells were named after the former province of Artois in France, where many artesian wells were drilled by Carthusian monks from 1126. Fluid mechanics Great Artesian Basin Hydrogeology Qanat Video of an artesian aquifer releasing water under its own pressure
9.
Effective stress
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Effective stress is a force that keeps a collection of particles rigid. Usually this applies to sand, soil, or gravel, if you pinch a stack of coins between your fingers, the stack stays together. If you then loosen the pressure between your fingers, the coin stack falls apart, similarly, a pile of sand keeps from spreading out like a liquid because the weight of the sand keeps the grains stuck together in their current arrangement, mostly out of static friction. This weight and pressure is the effective stress, effective stress is easy to disrupt by the application of additional forces, every footstep on a sand pile demonstrates this. It is an important factor in the study of stability and soil liquefaction. Karl von Terzaghi first proposed the relationship for effective stress in 1925, for him, the term effective meant the calculated stress that was effective in moving soil, or causing displacements. It represents the average stress carried by the soil skeleton, with these models, it is important to know the total weight of the soil above, and the pore water pressure within the slip plane, assuming it is acting as a confined layer. Consider a grouping of round quartz sand grains, piled loosely, as can be seen, there is a contact stress where the spheres actually touch. Pile on more spheres and the contact stresses increase, to the point of causing frictional instability, the independent parameter affecting the contacts is the force of the spheres above. This can be calculated by using the average density of the spheres. If we then have these spheres in a beaker and add some water, with natural soil materials, the effect can be significant, as anyone who has lifted a large rock out of a lake can attest. The contact stress on the spheres decreases as the beaker is filled to the top of the spheres, although the water pressure between the spheres is increasing, the effective stress remains the same, because the concept of total stress includes the weight of all the water above. This is where the equation can become confusing, and the stress can be calculated using the buoyant density of the spheres. The concept of effective stress truly becomes interesting when dealing with non-hydrostatic pore water pressure, under the conditions of a pore pressure gradient, the ground water flows, according to the permeability equation. Using our spheres as a model, this is the same as injecting water between the spheres, if water is being injected, the seepage force acts to separate the spheres and reduces the effective stress. Thus, the mass becomes weaker. If water is being withdrawn, the spheres are forced together, as well, effective stress plays an important role in slope stability, and other geotechnical engineering and engineering geology problems, such as groundwater-related subsidence
10.
Soil liquefaction
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In soil mechanics the term liquefied was first used by Allen Hazen in reference to the 1918 failure of the Calaveras Dam in California. The phenomenon is most often observed in saturated, loose, sandy soils and this is because a loose sand has a tendency to compress when a load is applied, dense sands by contrast tend to expand in volume or dilate. If the soil is saturated by water, a condition that exists when the soil is below the ground water table or sea level. In response to the soil compressing, this increases in pressure. These contacts between grains are the means by which the weight from buildings and overlying soil layers are transferred from the surface to layers of soil or rock at greater depths. This loss of soil structure causes it to all of its strength. Although the effects of liquefaction have been understood, it was more thoroughly brought to the attention of engineers after the 1964 Niigata earthquake and 1964 Alaska earthquake. It was also a factor in the destruction in San Franciscos Marina District during the 1989 Loma Prieta earthquake. A state of soil liquefaction occurs when the stress of soil is reduced to essentially zero. This may be initiated by either monotonic loading or cyclic loading, in both cases a soil in a saturated loose state, and one which may generate significant pore water pressure on a change in load are the most likely to liquefy. As pore water pressure rises a progressive loss of strength of the soil occurs as effective stress is reduced and it is more likely to occur in sandy or non-plastic silty soils, but may in rare cases occur in gravels and clays. A flow failure may initiate if the strength of the soil is reduced below the required to maintain equilibrium of a slope or footing of a building for instance. This can occur due to loading or cyclic loading, and can be sudden. A historical example is the Aberfan disaster, casagrande referred to this type of phenomena as flow liquefaction although a state of zero effective stress is not required for this to occur. The term cyclic refers to the occurrence of a state of soil when large shear strains have accumulated in response to cyclic loading. A typical reference strain for the occurrence of zero effective stress is 5% double amplitude shear strain. This is a soil test based definition, usually performed via cyclic triaxial, cyclic direct simple shear and these tests are performed to determine a soils resistance to liquefaction by observing the number of cycles of loading at a particular shear stress amplitude before it fails. Failure here is defined by the shear strain criteria
11.
Earthquake
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An earthquake is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earths lithosphere that creates seismic waves. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to people around. The seismicity or seismic activity of an area refers to the frequency, type, Earthquakes are measured using measurements from seismometers. The moment magnitude is the most common scale on which earthquakes larger than approximately 5 are reported for the entire globe and these two scales are numerically similar over their range of validity. Magnitude 3 or lower earthquakes are mostly imperceptible or weak and magnitude 7 and over potentially cause damage over larger areas. The largest earthquakes in historic times have been of magnitude slightly over 9, intensity of shaking is measured on the modified Mercalli scale. The shallower an earthquake, the damage to structures it causes. At the Earths surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground, when the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides, and occasionally volcanic activity, in its most general sense, the word earthquake is used to describe any seismic event — whether natural or caused by humans — that generates seismic waves. Earthquakes are caused mostly by rupture of faults, but also by other events such as volcanic activity, landslides, mine blasts. An earthquakes point of rupture is called its focus or hypocenter. The epicenter is the point at ground level directly above the hypocenter, tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane. The sides of a fault move past each other smoothly and aseismically only if there are no irregularities or asperities along the surface that increase the frictional resistance. Most fault surfaces do have such asperities and this leads to a form of stick-slip behavior, once the fault has locked, continued relative motion between the plates leads to increasing stress and therefore, stored strain energy in the volume around the fault surface. This continues until the stress has risen sufficiently to break through the asperity, suddenly allowing sliding over the portion of the fault. This energy is released as a combination of radiated elastic strain seismic waves, frictional heating of the fault surface and this process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the elastic-rebound theory. It is estimated that only 10 percent or less of a total energy is radiated as seismic energy. Most of the energy is used to power the earthquake fracture growth or is converted into heat generated by friction
12.
Pore water pressure
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Pore water pressure refers to the pressure of groundwater held within a soil or rock, in gaps between particles. Pore water pressures in below the level are measured in piezometers. The vertical pore water pressure distribution in aquifers can generally be assumed to be close to hydrostatic, in the unsaturated zone, the pore pressure is determined by capillarity and is also referred to as tension, suction, or matric pressure. Pore water pressures under unsaturated conditions are measured in with tensiometers, tensiometers operate by allowing the pore water to come into equilibrium with a reference pressure indicator through a permeable ceramic cup placed in contact with the soil. Pore water pressure is vital in calculating the stress state in the soil mechanics. Hydrostatic water pressure, resulting from the weight of material above the point measured, osmotic pressure, inhomogeneous aggregation of ion concentrations, which causes a force in water particles as they attract by the molecular laws of attraction. Adsorption pressure, attraction of surrounding soil particles to one another by adsorbed water films, the buoyancy effects of water have a large impact on certain soil properties, such as the effective stress present at any point in a soil medium. Consider an arbitrary point five meters below the ground surface, in dry soil, particles at this point experience a total overhead stress equal to the depth underground, multiplied by the specific weight of the soil.81 kN/m^3. This parameter is called the stress of the soil, basically equal to the difference in a soils total stress. The pore water pressure is essential in differentiating a soils total stress from its effective stress, a correct representation of stress in soil is necessary for accurate field calculations in a variety of engineering trades. The static pressure of groundwater at a specific depth, piezometers often employ electronic pressure transducers to provide data. The United States Bureau of Reclamation has a standard for monitoring water pressure in a mass with piezometers. It sites ASTM D4750, Standard Test Method for Determining Subsurface Liquid Levels in a Borehole or Monitoring Well, at any point above the water table, in the vadose zone, the effective stress is approximately equal to the total stress, as proven by Terzaghis principle. Realistically, the stress is greater than the total stress. This is primarily due to the tension of pore water in voids throughout the vadose zone causing a suction effect on surrounding particles. This capillary action is the movement of water through the vadose zone. The height of rise is inversely proportional to the diameter of void space in contact with water. Therefore, the smaller the space, the higher water will rise due to tension forces
13.
Bank (geography)
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In geography, the word bank generally refers to the land alongside a body of water. Different structures are referred to as banks in different fields of geography, in limnology, a stream bank or river bank is the terrain alongside the bed of a river, creek, or stream. The bank consists of the sides of the channel, between which the flow is confined, stream banks are of particular interest in fluvial geography, which studies the processes associated with rivers and streams and the deposits and landforms created by them. The shoreline of ponds, swamps, estuaries, reservoirs, or lakes are also of interest in limnology, the grade of all these banks or shorelines can vary from vertical to a shallow slope. In freshwater ecology, banks are of interest as the location of riparian habitats, riparian zones occur along upland and lowland river and stream beds. The ecology around and depending on a marsh, swamp, slough, or estuary, banks are also of interest in navigation, where the term can refer either to a barrier island or a submerged plateau, such as an ocean bank. A barrier island is a narrow island composed of sand. A submerged plateau is a flat topped elevation of the sea floor at shallow depth
14.
Lake
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A lake is an area of variable size filled with water, localized in a basin, that is surrounded by land, apart from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, and therefore are distinct from lagoons, Lakes can be contrasted with rivers or streams, which are usually flowing. Most lakes are fed and drained by rivers and streams, natural lakes are generally found in mountainous areas, rift zones, and areas with ongoing glaciation. Other lakes are found in endorheic basins or along the courses of mature rivers, in some parts of the world there are many lakes because of chaotic drainage patterns left over from the last Ice Age. All lakes are temporary over geologic time scales, as they will fill in with sediments or spill out of the basin containing them. The word lake comes from Middle English lake, from Old English lacu, from Proto-Germanic *lakō, cognates include Dutch laak, Middle Low German lāke as in, de, Moorlake, de, Wolfslake, de, Butterlake, German Lache, and Icelandic lækur. Also related are the English words leak and leach, none of these definitions completely excludes ponds and all are difficult to measure. For this reason, simple size-based definitions are used to separate ponds. One definition of lake is a body of water of 2 hectares or more in area, however, others have defined lakes as waterbodies of 5 hectares and above, or 8 hectares and above. Charles Elton, one of the founders of ecology, regarded lakes as waterbodies of 40 hectares or more. The term lake is used to describe a feature such as Lake Eyre. In common usage, many bear names ending with the word pond. One textbook illustrates this point with the following, In Newfoundland, for example, almost every lake is called a pond, whereas in Wisconsin, the majority of lakes on Earth are fresh water, and most lie in the Northern Hemisphere at higher latitudes. Canada, with a drainage system has an estimated 31,752 lakes larger than 3 square kilometres and an unknown total number of lakes. Finland has 187,888 lakes 500 square metres or larger, most lakes have at least one natural outflow in the form of a river or stream, which maintain a lakes average level by allowing the drainage of excess water. Some lakes do not have an outflow and lose water solely by evaporation or underground seepage or both. Many lakes are artificial and are constructed for power generation, aesthetic purposes, recreational purposes, industrial use. Globally, lakes are greatly outnumbered by ponds, of an estimated 304 million standing water bodies worldwide, 91% are 1 hectare or less in area
15.
Marsh
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A marsh is a wetland that is dominated by herbaceous rather than woody plant species. Marshes can often be found at the edges of lakes and streams and they are often dominated by grasses, rushes or reeds. If woody plants are present they tend to be low-growing shrubs, Marshes provide a habitat for many species of plants, animals, and insects that have adapted to living in flooded conditions. The plants must be able to survive in wet mud with low oxygen levels, many of these plants therefore have aerenchyma, channels within the stem that allow air to move from the leaves into the rooting zone. Marsh plants also tend to have rhizomes for underground storage and reproduction, familiar examples include cattails, sedges, papyrus and sawgrass. Aquatic animals, from fish to salamanders, are able to live with a low amount of oxygen in the water. Some can obtain oxygen from the air instead, while others can live indefinitely in conditions of low oxygen, Marshes provide habitats for many kinds of invertebrates, fish, amphibians, waterfowl and aquatic mammals. Marshes have extremely high levels of production, some of the highest in the world. Marshes also improve water quality by acting as a sink to filter pollutants, Marshes are able to absorb water during periods of heavy rainfall and slowly release it into waterways and therefore reduce the magnitude of flooding. The pH in marshes tends to be neutral to alkaline, as opposed to bogs, Marshes differ depending mainly on their location and salinity. Both of these factors influence the range and scope of animal and plant life that can survive. The three main types of marsh are salt marshes, freshwater marshes, and freshwater marshes. These three can be found worldwide and each contains a different set of organisms, saltwater marshes are found around the world in mid to high latitudes, wherever there are sections of protected coastline. They are located close enough to the shoreline that the motion of the tides affects them and they flourish where the rate of sediment buildup is greater than the rate at which the land level is sinking. Salt marshes are dominated by specially adapted rooted vegetation, primarily salt-tolerant grasses, salt marshes are most commonly found in lagoons, estuaries, and on the sheltered side of shingle or sandspit. The currents there carry the fine particles around to the side of the spit. These locations allow the marshes to absorb the nutrients from the water running through them before they reach the oceans. Coastal development and urban sprawl has caused significant loss of these essential habitats, although considered a freshwater marsh, this form of marsh is affected by the ocean tides
16.
Shear thinning
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In rheology, shear thinning is the non-Newtonian behavior of fluids whose viscosity decreases under shear strain. It is sometimes considered synonymous for pseudoplastic behaviour, and is defined as excluding time-dependent effects. Some authors consider shear-thinning to be a case of thixotropic behaviour. When it takes a time for the viscosity to recover. Modern paints are examples of pseudoplastic materials, when modern paints are applied the shear created by the brush or roller will allow them to thin and wet out the surface evenly. Once applied the paints regain their higher viscosity which avoids drips, Ketchup is a shear-thinning fluid, caused by the addition of a relatively small amount of Xanthan gum - usually 0. 5%. Non-Newtonian fluid Power-law fluid Thixotropy Dilatant Rheology Kaye effect The Great Ketchup Mystery NASA - The Physics of Whipped Cream NASA April 25,2008 References
17.
Non-Newtonian fluid
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A non-Newtonian fluid is a fluid that does not follow Newtons Law of Viscosity. Most commonly, the viscosity of fluids is dependent on shear rate or shear rate history. Some non-Newtonian fluids with shear-independent viscosity, however, still exhibit normal stress-differences or other non-Newtonian behavior. Many salt solutions and molten polymers are non-Newtonian fluids, as are commonly found substances such as ketchup, custard, toothpaste, starch suspensions, maizena, paint, blood. In a Newtonian fluid, the relation between the stress and the shear rate is linear, passing through the origin, the constant of proportionality being the coefficient of viscosity. In a non-Newtonian fluid, the relation between the stress and the shear rate is different and can even be time-dependent. Therefore, a constant coefficient of viscosity cannot be defined, although the concept of viscosity is commonly used in fluid mechanics to characterize the shear properties of a fluid, it can be inadequate to describe non-Newtonian fluids. The properties are studied using tensor-valued constitutive equations, which are common in the field of continuum mechanics. The viscosity of a shear thickening fluid, or dilatant fluid, corn starch dissolved in water is a common example, when stirred slowly it looks milky, when stirred vigorously it feels like a very viscous liquid. Note that all thixotropic fluids are extremely shear thinning, but they are time dependent. Thus, to avoid confusion, the classification is more clearly termed pseudoplastic. Another example of a shear thinning fluid is blood and this application is highly favoured within the body, as it allows the viscosity of blood to decrease with increased shear strain rate. Fluids that have a linear shear stress/shear strain relationship require a finite yield stress before they begin to flow and these fluids are called Bingham plastics. Several examples are clay suspensions, drilling mud, toothpaste, mayonnaise, chocolate, the surface of a Bingham plastic can hold peaks when it is still. By contrast Newtonian fluids have flat featureless surfaces when still, there are also fluids whose strain rate is a function of time. Fluids that require a gradually increasing shear stress to maintain a constant strain rate are referred to as rheopectic, an opposite case of this is a fluid that thins out with time and requires a decreasing stress to maintain a constant strain rate. Many common substances exhibit non-Newtonian flows, uncooked cornflour has the same properties. The name oobleck is derived from the Dr. Seuss book Bartholomew, because of its properties, oobleck is often used in demonstrations that exhibit its unusual behavior
18.
Phase (matter)
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In the physical sciences, a phase is a region of space, throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, index of refraction, magnetization, a simple description is that a phase is a region of material that is chemically uniform, physically distinct, and mechanically separable. In a system consisting of ice and water in a jar, the ice cubes are one phase, the water is a second phase. The glass of the jar is another separate phase, the term phase is sometimes used as a synonym for state of matter, but there can be several immiscible phases of the same state of matter. Also, the phase is sometimes used to refer to a set of equilibrium states demarcated in terms of state variables such as pressure and temperature by a phase boundary on a phase diagram. Distinct phases may be described as different states of such as gas, liquid, solid. Useful mesophases between solid and liquid form other states of matter, distinct phases may also exist within a given state of matter. As shown in the diagram for iron alloys, several phases exist for both the solid and liquid states, phases may also be differentiated based on solubility as in polar or non-polar. A mixture of water and oil will separate into two phases. Water has a low solubility in oil, and oil has a low solubility in water. Solubility is the amount of a solute that can dissolve in a solvent before the solute ceases to dissolve. A mixture can separate into more than two phases and the concept of phase separation extends to solids, i. e. solids can form solid solutions or crystallize into distinct crystal phases. Metal pairs that are mutually soluble can form alloys, whereas metal pairs that are mutually insoluble cannot, as many as eight immiscible liquid phases have been observed. Mutually immiscible liquid phases are formed from water, hydrophobic solvents, perfluorocarbons, silicones, several different metals. Not all organic solvents are completely miscible, e. g. a mixture of ethylene glycol, phases do not need to macroscopically separate spontaneously. Emulsions and colloids are examples of immiscible phase pair combinations that do not physically separate, left to equilibration, many compositions will form a uniform single phase, but depending on the temperature and pressure even a single substance may separate into two or more distinct phases. Within each phase, the properties are uniform but between the two phases properties differ, water in a closed jar with an air space over it forms a two phase system. Most of the water is in the phase, where it is held by the mutual attraction of water molecules
19.
Stress (physics)
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For example, when a solid vertical bar is supporting a weight, each particle in the bar pushes on the particles immediately below it. When a liquid is in a container under pressure, each particle gets pushed against by all the surrounding particles. The container walls and the pressure-inducing surface push against them in reaction and these macroscopic forces are actually the net result of a very large number of intermolecular forces and collisions between the particles in those molecules. Strain inside a material may arise by various mechanisms, such as stress as applied by external forces to the material or to its surface. Any strain of a material generates an internal elastic stress, analogous to the reaction force of a spring. In liquids and gases, only deformations that change the volume generate persistent elastic stress, however, if the deformation is gradually changing with time, even in fluids there will usually be some viscous stress, opposing that change. Elastic and viscous stresses are usually combined under the mechanical stress. Significant stress may exist even when deformation is negligible or non-existent, stress may exist in the absence of external forces, such built-in stress is important, for example, in prestressed concrete and tempered glass. Stress may also be imposed on a material without the application of net forces, for example by changes in temperature or chemical composition, stress that exceeds certain strength limits of the material will result in permanent deformation or even change its crystal structure and chemical composition. In some branches of engineering, the stress is occasionally used in a looser sense as a synonym of internal force. For example, in the analysis of trusses, it may refer to the total traction or compression force acting on a beam, since ancient times humans have been consciously aware of stress inside materials. Until the 17th century the understanding of stress was largely intuitive and empirical, with those tools, Augustin-Louis Cauchy was able to give the first rigorous and general mathematical model for stress in a homogeneous medium. Cauchy observed that the force across a surface was a linear function of its normal vector, and, moreover. The understanding of stress in liquids started with Newton, who provided a formula for friction forces in parallel laminar flow. Stress is defined as the force across a small boundary per unit area of that boundary, following the basic premises of continuum mechanics, stress is a macroscopic concept. In a fluid at rest the force is perpendicular to the surface, in a solid, or in a flow of viscous liquid, the force F may not be perpendicular to S, hence the stress across a surface must be regarded a vector quantity, not a scalar. Moreover, the direction and magnitude depend on the orientation of S. Thus the stress state of the material must be described by a tensor, called the stress tensor, with respect to any chosen coordinate system, the Cauchy stress tensor can be represented as a symmetric matrix of 3×3 real numbers
20.
Viscosity
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The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress. For liquids, it corresponds to the concept of thickness, for example. Viscosity is a property of the fluid which opposes the motion between the two surfaces of the fluid in a fluid that are moving at different velocities. For a given velocity pattern, the stress required is proportional to the fluids viscosity, a fluid that has no resistance to shear stress is known as an ideal or inviscid fluid. Zero viscosity is observed only at low temperatures in superfluids. Otherwise, all fluids have positive viscosity, and are said to be viscous or viscid. A fluid with a high viscosity, such as pitch. The word viscosity is derived from the Latin viscum, meaning mistletoe, the dynamic viscosity of a fluid expresses its resistance to shearing flows, where adjacent layers move parallel to each other with different speeds. It can be defined through the situation known as a Couette flow. This fluid has to be homogeneous in the layer and at different shear stresses, if the speed of the top plate is small enough, the fluid particles will move parallel to it, and their speed will vary linearly from zero at the bottom to u at the top. Each layer of fluid will move faster than the one just below it, in particular, the fluid will apply on the top plate a force in the direction opposite to its motion, and an equal but opposite one to the bottom plate. An external force is required in order to keep the top plate moving at constant speed. The magnitude F of this force is found to be proportional to the u and the area A of each plate. The proportionality factor μ in this formula is the viscosity of the fluid, the ratio u/y is called the rate of shear deformation or shear velocity, and is the derivative of the fluid speed in the direction perpendicular to the plates. Isaac Newton expressed the forces by the differential equation τ = μ ∂ u ∂ y, where τ = F/A. This formula assumes that the flow is moving along parallel lines and this equation can be used where the velocity does not vary linearly with y, such as in fluid flowing through a pipe. Use of the Greek letter mu for the dynamic viscosity is common among mechanical and chemical engineers. However, the Greek letter eta is used by chemists, physicists
21.
Sediment
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For sediment in beverages, see dregs. For example, sand and silt can be carried in suspension in water and on reaching the sea be deposited by sedimentation. Sediments are most often transported by water, but also wind, beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of transport and deposition. Glacial moraine deposits and till are ice-transported sediments, sediment can be classified based on its grain size and/or its composition. Sediment size is measured on a log base 2 scale, called the Phi scale, composition of sediment can be measured in terms of, parent rock lithology mineral composition chemical make-up. This leads to an ambiguity in which clay can be used as both a size-range and a composition, sediment is transported based on the strength of the flow that carries it and its own size, volume, density, and shape. Stronger flows will increase the lift and drag on the particle, causing it to rise, rivers and streams carry sediment in their flows. This sediment can be in a variety of locations within the flow and these relationships are shown in the following table for the Rouse number, which is a ratio of sediment fall velocity to upwards velocity. If the upwards velocity is less than the settling velocity, but still high enough for the sediment to move, it will move along the bed as bed load by rolling, sliding. If the upwards velocity is higher than the velocity, the sediment will be transported high in the flow as wash load. As there are generally a range of different particle sizes in the flow, sediment motion can create self-organized structures such as ripples, dunes, antidunes on the river or stream bed. These bedforms are often preserved in rocks and can be used to estimate the direction. Overland flow can erode soil particles and transport them downslope, the erosion associated with overland flow may occur through different methods depending on meteorological and flow conditions. If the initial impact of rain droplets dislodges soil, the phenomenon is called rainsplash erosion, if overland flow is directly responsible for sediment entrainment but does not form gullies, it is called sheet erosion. If the flow and the substrate permit channelization, gullies may form, glaciers carry a wide range of sediment sizes, and deposit it in moraines. The overall balance between sediment in transport and sediment being deposited on the bed is given by the Exner equation and this expression states that the rate of increase in bed elevation due to deposition is proportional to the amount of sediment that falls out of the flow. This can be localized, and simply due to obstacles, examples are scour holes behind boulders, where flow accelerates
22.
Pressure
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Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure is the relative to the ambient pressure. Various units are used to express pressure, Pressure may also be expressed in terms of standard atmospheric pressure, the atmosphere is equal to this pressure and the torr is defined as 1⁄760 of this. Manometric units such as the centimetre of water, millimetre of mercury, Pressure is the amount of force acting per unit area. The symbol for it is p or P, the IUPAC recommendation for pressure is a lower-case p. However, upper-case P is widely used. The usage of P vs p depends upon the field in one is working, on the nearby presence of other symbols for quantities such as power and momentum. Mathematically, p = F A where, p is the pressure, F is the normal force and it relates the vector surface element with the normal force acting on it. It is incorrect to say the pressure is directed in such or such direction, the pressure, as a scalar, has no direction. The force given by the relationship to the quantity has a direction. If we change the orientation of the element, the direction of the normal force changes accordingly. Pressure is distributed to solid boundaries or across arbitrary sections of normal to these boundaries or sections at every point. It is a parameter in thermodynamics, and it is conjugate to volume. The SI unit for pressure is the pascal, equal to one newton per square metre and this name for the unit was added in 1971, before that, pressure in SI was expressed simply in newtons per square metre. Other units of pressure, such as pounds per square inch, the CGS unit of pressure is the barye, equal to 1 dyn·cm−2 or 0.1 Pa. Pressure is sometimes expressed in grams-force or kilograms-force per square centimetre, but using the names kilogram, gram, kilogram-force, or gram-force as units of force is expressly forbidden in SI. The technical atmosphere is 1 kgf/cm2, since a system under pressure has potential to perform work on its surroundings, pressure is a measure of potential energy stored per unit volume. It is therefore related to density and may be expressed in units such as joules per cubic metre. Similar pressures are given in kilopascals in most other fields, where the prefix is rarely used
23.
Liquefaction
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Liquefaction occurs both as part of natural processes, and in man-made processes used in science and commerce. In geology, soil liquefaction refers to the process by which water-saturated, unconsolidated sediments are transformed into a substance that acts like a liquid, by undermining the foundations and base courses of infrastructure, liquefaction can cause serious damage. In physics and chemistry, the transitions from solid and gas to liquid may be referred to as liquefaction. The melting point is the temperature and pressure at which a solid becomes a liquid, in commercial and industrial situations, the process of condensing a gas to liquid is sometimes referred to as liquefaction of gases. Coal liquefaction is the production of fuels from coal using a variety of industrial processes. Liquefaction is also used in commercial and industrial settings to refer to mechanical dissolution of a solid by mixing, grinding or blending with a liquid. In kitchen or laboratory settings, solids may be chopped into smaller parts sometimes in combination with a liquid and this may be done with a blender, or liquidiser in British English. In biology, liquefaction often involves organic tissue turning into a more liquid-like state, for example, liquefactive necrosis in pathology, or liquefaction as a parameter in semen analysis
24.
Force
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In physics, a force is any interaction that, when unopposed, will change the motion of an object. In other words, a force can cause an object with mass to change its velocity, force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity and it is measured in the SI unit of newtons and represented by the symbol F. The original form of Newtons second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time. In an extended body, each part usually applies forces on the adjacent parts, such internal mechanical stresses cause no accelation of that body as the forces balance one another. Pressure, the distribution of small forces applied over an area of a body, is a simple type of stress that if unbalanced can cause the body to accelerate. Stress usually causes deformation of materials, or flow in fluids. In part this was due to an understanding of the sometimes non-obvious force of friction. A fundamental error was the belief that a force is required to maintain motion, most of the previous misunderstandings about motion and force were eventually corrected by Galileo Galilei and Sir Isaac Newton. With his mathematical insight, Sir Isaac Newton formulated laws of motion that were not improved-on for nearly three hundred years, the Standard Model predicts that exchanged particles called gauge bosons are the fundamental means by which forces are emitted and absorbed. Only four main interactions are known, in order of decreasing strength, they are, strong, electromagnetic, weak, high-energy particle physics observations made during the 1970s and 1980s confirmed that the weak and electromagnetic forces are expressions of a more fundamental electroweak interaction. Since antiquity the concept of force has been recognized as integral to the functioning of each of the simple machines. The mechanical advantage given by a machine allowed for less force to be used in exchange for that force acting over a greater distance for the same amount of work. Analysis of the characteristics of forces ultimately culminated in the work of Archimedes who was famous for formulating a treatment of buoyant forces inherent in fluids. Aristotle provided a discussion of the concept of a force as an integral part of Aristotelian cosmology. In Aristotles view, the sphere contained four elements that come to rest at different natural places therein. Aristotle believed that objects on Earth, those composed mostly of the elements earth and water, to be in their natural place on the ground. He distinguished between the tendency of objects to find their natural place, which led to natural motion, and unnatural or forced motion
25.
Density
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The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume. The symbol most often used for density is ρ, although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume, ρ = m V, where ρ is the density, m is the mass, and V is the volume. In some cases, density is defined as its weight per unit volume. For a pure substance the density has the numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity, osmium and iridium are the densest known elements at standard conditions for temperature and pressure but certain chemical compounds may be denser. Thus a relative density less than one means that the floats in water. The density of a material varies with temperature and pressure and this variation is typically small for solids and liquids but much greater for gases. Increasing the pressure on an object decreases the volume of the object, increasing the temperature of a substance decreases its density by increasing its volume. In most materials, heating the bottom of a results in convection of the heat from the bottom to the top. This causes it to rise relative to more dense unheated material, the reciprocal of the density of a substance is occasionally called its specific volume, a term sometimes used in thermodynamics. Density is a property in that increasing the amount of a substance does not increase its density. Archimedes knew that the irregularly shaped wreath could be crushed into a cube whose volume could be calculated easily and compared with the mass, upon this discovery, he leapt from his bath and ran naked through the streets shouting, Eureka. As a result, the term eureka entered common parlance and is used today to indicate a moment of enlightenment, the story first appeared in written form in Vitruvius books of architecture, two centuries after it supposedly took place. Some scholars have doubted the accuracy of this tale, saying among other things that the method would have required precise measurements that would have been difficult to make at the time, from the equation for density, mass density has units of mass divided by volume. As there are units of mass and volume covering many different magnitudes there are a large number of units for mass density in use. The SI unit of kilogram per metre and the cgs unit of gram per cubic centimetre are probably the most commonly used units for density.1,000 kg/m3 equals 1 g/cm3. In industry, other larger or smaller units of mass and or volume are often more practical, see below for a list of some of the most common units of density
26.
Tide
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Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth. Some shorelines experience a semi-diurnal tide—two nearly equal high and low tides each day, other locations experience a diurnal tide—only one high and low tide each day. A mixed tide—two uneven tides a day, or one high, Tides vary on timescales ranging from hours to years due to a number of factors. To make accurate records, tide gauges at fixed stations measure water level over time, gauges ignore variations caused by waves with periods shorter than minutes. These data are compared to the level usually called mean sea level. Tidal phenomena are not limited to the oceans, but can occur in other systems whenever a gravitational field varies in time. For example, the part of the Earth is affected by tides. Tide changes proceed via the following stages, Sea level rises over several hours, covering the intertidal zone, the water rises to its highest level, reaching high tide. Sea level falls over several hours, revealing the intertidal zone, the water stops falling, reaching low tide. Oscillating currents produced by tides are known as tidal streams, the moment that the tidal current ceases is called slack water or slack tide. The tide then reverses direction and is said to be turning, slack water usually occurs near high water and low water. But there are locations where the moments of slack tide differ significantly from those of high, Tides are commonly semi-diurnal, or diurnal. The two high waters on a day are typically not the same height, these are the higher high water. Similarly, the two low waters each day are the low water and the lower low water. The daily inequality is not consistent and is small when the Moon is over the equator. From the highest level to the lowest, Highest Astronomical Tide – The highest tide which can be predicted to occur, note that meteorological conditions may add extra height to the HAT. Mean High Water Springs – The average of the two high tides on the days of spring tides, mean High Water Neaps – The average of the two high tides on the days of neap tides. Mean Sea Level – This is the sea level
27.
Carnivore
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Animals that depend solely on animal flesh for their nutrient requirements are called obligate carnivores while those that also consume non-animal food are called facultative carnivores. A carnivore that sits at the top of the chain is termed an apex predator. Plants that capture and digest insects are called carnivorous plants, similarly, fungi that capture microscopic animals are often called carnivorous fungi. The word carnivore sometimes refers to the mammalian order Carnivora, while many Carnivora meet the definition of being meat eaters, not all do, and even fewer are true obligate carnivores. In addition, there are plenty of species that are not members of Carnivora. Outside the animal kingdom, there are several genera containing carnivorous plants, the former are predominantly insectivores, while the latter prey mostly on microscopic invertebrates, such as nematodes, amoebae and springtails. Carnivores are sometimes characterized by the type of prey that they consume, for example, animals that eat insects and similar invertebrates primarily or exclusively are called insectivores, while those that eat fish primarily or exclusively are called piscivores. The first tetrapods, or land-dwelling vertebrates, were piscivorous amphibians known as labyrinthodonts and they gave rise to insectivorous vertebrates and, later, to predators of other tetrapods. Carnivores may alternatively be classified according to the percentage of meat in their diet, obligate carnivores or true carnivores depend on the nutrients found only in animal flesh for their survival. For instance, felids including the cat are obligate carnivores requiring a diet of primarily animal flesh. Characteristics commonly associated with carnivores include organs for capturing and disarticulating prey, in truth, these assumptions may be misleading, as some carnivores do not hunt and are scavengers. Thus they do not have the associated with hunting carnivores. Carnivores have comparatively short digestive systems, as they are not required to break down tough cellulose found in plants, many animals that hunt other animals have evolved eyes that face forward, thus making depth perception possible. This is almost universal among mammalian predators, other predators, like crocodiles, as well as most reptiles and amphibians, have sideways facing eyes and hunt by ambush rather than pursuit. The first vertebrate carnivores were fish, and then amphibians that moved on to land, early tetrapods were large amphibious piscivores. Some scientists assert that Dimetrodon was the first terrestrial vertebrate to develop the curved, serrated teeth that enable a predator to eat prey much larger than itself. While amphibians continued to feed on fish and later insects, reptiles began exploring two new types, tetrapods, and later, plants. Carnivory was a transition from insectivory for medium and large tetrapods
28.
Supine position
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The supine position means lying horizontally with the face and torso facing up, as opposed to the prone position, which is face down. When used in procedures, it allows access to the peritoneal, thoracic and pericardial regions, as well as the head, neck. Using anatomical terms of location, the side is down, and the ventral side is up. In scientific literature semi-supine commonly refers to positions where the body is tilted. The decline in death due to sudden infant death syndrome is said to be attributable to having babies sleep in the supine position and it is believed that in the prone position babies are more at risk to re-breathe their own carbon dioxide. Because of the state of their central chemoreceptors, infants do not respond to the subsequent respiratory acidosis that develops. Obstructive sleep apnea is a form of sleep apnea that occurs more frequently, anatomical position Decubitus Lying position Prone position Sleep paralysis
29.
Slate (magazine)
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Slate is an online liberal / progressive magazine that covers current affairs, politics and culture in the United States. It was created in 1996 by former New Republic editor Michael Kinsley, on 21 December 2004, it was purchased by The Washington Post Company, later renamed the Graham Holdings Company. Since 4 June 2008, Slate has been managed by The Slate Group, Slate is based in New York City, with an additional office in Washington, DC. A French version was launched in February 2009 by a group of four journalists, including Jean-Marie Colombani, Eric Leser, among them, the founders hold 50% in the publishing company, while The Slate Group holds 15%. In 2011, slate. fr started a separate site covering African news, Slate Afrique, in July 2014, Julia Turner replaced David Plotz, who had been editor of Slate since 2008. Plotz had been the deputy editor to Jacob Weisberg, Slates editor from 2002 until his designation as the Chairman, the Washington Post Companys John Alderman is Slates publisher. Slate, which is updated throughout the day, covers politics, arts and culture, sports, as of mid-2015, it publishes about 1500 stories per month. Slate is also known for adopting contrarian views, giving rise to the term Slate Pitches and it is ad-supported and has been available to read free of charge since 1999, but restricted access for non-US readers via a metered paywall in 2015. Slate features regular and semi-regular columns such as Explainer, Moneybox, Spectator, Transport, many of the articles are short and argument-driven. Around 2010, the magazine began running long-form journalism. Many of the stories are an outgrowth of the Fresca Fellowships. In the context of a 2014 reader discussion, it was stated that the magazine is perceived to have left-liberal leanings, in 1998, Slate introduced a paywall-based business model that attracted up 20,000 subscribers but was abandoned afterwards. A similar subscription model would later be implemented by Slates independently owned competitor, Salon. com, on November 30,2005, Slate started a daily feature ”Todays Pictures”, featuring fifteen to twenty photographs from the archive at Magnum Photos that share a common theme. The column also features two flash animated ”Interactive Essays” a month, in June 2006, on its tenth anniversary, Slate unveiled a redesigned website. In 2007, it introduced Slate V, a video magazine with content that relates to or expands upon their written articles. In 2013, the magazine was redesigned under the guidance of Design Director Vivian Selbo, in 2011, Slate was nominated for four digital National Magazine Awards and won the NMA for General Excellence. In the same year, the laid off several high-profile journalists, including co-founder Jack Shafer. At the time, it had around 40 full-time editorial staff, the following year, a dedicated ad sales team was created
30.
Cyberculture
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Cyberculture or computer culture is the culture that has emerged, or is emerging, from the use of computer networks for communication, entertainment, and business. Since the boundaries of cyberculture are difficult to define, the term is used flexibly and it can also embrace associated intellectual and cultural movements, such as cyborg theory and cyberpunk. The term often incorporates an implicit anticipation of the future, the Oxford English Dictionary lists the earliest usage of the term cyberculture in 1963, when A. M. Hilton wrote the following, In the era of cyberculture, all the plows pull themselves and this example, and all others, up through 1995 are used to support the definition of cyberculture as the social conditions brought about by automation and computerization. However, what both the OED and the American Heritage Dictionary miss is that cyberculture is the culture within and this cyberculture may be purely an online culture or it may span both virtual and physical worlds. This is to say, that cyberculture is an endemic to online communities, it is not just the culture that results from computer use. Another way to envision cyberculture is as the electronically enabled linkage of like-minded, Cyberculture was influenced at its genesis by those early users of the internet, frequently including the architects of the original project. These individuals were often guided in their actions by the hacker ethic, while early cyberculture was based on a small cultural sample, and its ideals, the modern cyberculture is a much more diverse group of users and the ideals that they espouse. Numerous specific concepts of cyberculture have been formulated by such authors as Lev Manovich, Arturo Escobar, however, most of these concepts concentrate only on certain aspects, and they do not cover these in great detail. Manifestations of cyberculture include various human interactions mediated by computer networks and they can be activities, pursuits, games, places and metaphors, and include a diverse base of applications. Some are supported by specialized software and others work on commonly accepted internet protocols, examples include but are not limited to, First and foremost, cyberculture derives from traditional notions of culture, as the roots of the word imply. In non-cyberculture, it would be odd to speak of a single, in cyberculture, by extension, searching for a single thing that is cyberculture would likely be problematic. The notion that there is a single, definable cyberculture is likely the complete dominance of early cyber territory by affluent North Americans, writing by early proponents of cyberspace tends to reflect this assumption. The ethnography of cyberspace is an important aspect of cyberculture that does not reflect a unified culture. It is not a monolithic or placeless cyberspace, rather, it is numerous new technologies and capabilities, used by diverse people and it is malleable, perishable, and can be shaped by the vagaries of external forces on its users. For example, the laws of physical world governments, social norms, the architecture of cyberspace, as with physical world cultures, cybercultures lend themselves to identification and study. There are several qualities that cybercultures share that make them warrant the prefix cyber-, some of those qualities are that cyberculture, Is a community mediated by ICTs. Is culture mediated by computer screens, relies heavily on the notion of information and knowledge exchange
31.
Archer (TV series)
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Archer is an American adult animated spy sitcom created by Adam Reed for the FX network. The series formerly aired on FX from September 17,2009 to June 2,2016, on June 21,2016, FX renewed the series for an eighth, ninth, and tenth season, each to consist of eight episodes. The eighth season premiered on April 5,2017, with the moving to sister network FXX. Reed indicated in September 2016 that he planned to end the series after the tenth season, a season-long arc took place in the fifth season, re-configuring the show from a spy series to a Miami Vice-style satire of the drug industry. To reflect this, the season was titled Archer Vice, when ISIS is disbanded by the U. S. government, its employees take a stockpile of cocaine that they acquired from previous operations and form a drug cartel to fund their retirements. Meanwhile, Cheryl decides to launch a new career as a country singer, in the sixth season, the series returned to the spy format, and essentially unrebooted the characters back to their personalities before the fifth season. The characters now started working as contractors for the CIA, the seventh season once again retooled the show, after the characters were fired from the CIA and blacklisted from espionage in the sixth-season finale following failure during a mission. They move to Los Angeles, California to start their own detective agency. The show once again took on a serialized, season-long story arc and this season resolves the cliffhanger from last season which was revealed that Archer has been in a coma for three months, but finds himself trapped in a 1940s noir-esque setting called Dreamland. The shows time setting is comically anachronistic, deliberately mixing technologies, clothing styles and it also contains references to Fidel Castro as the current leader of Cuba. This ambiguity is alluded to in at least two episodes, in characters are unable to answer when asked what year they think it is. Sterling Malory Archer is considered the worlds most dangerous secret agent and he is extremely egotistical and self-involved, and usually doesnt take any situation seriously. His obsessions include Burt Reynolds, Kenny Loggins, and big cats such as tigers, Archers favorite catch-phrases include the exclamation Phrasing. I had something for this, and Danger Zone, said in expected situations, despite his gross negligence, incompetence, and willful ignorance, Archer is usually successful to some degree in most of his endeavors, though sometimes due to blind luck. He possesses a knowledge of pop culture and literature. His biggest fears are, cyborgs, alligators, crocodiles, Lana Anthony Kane is the top female agent at ISIS. She is a competent and deadly agent but is frustrated that she is treated as the number two ISIS field agent behind Sterling, as his mother runs the agency. She has dated Archer in the past and they have had an on again relationship before dating Cyril
32.
Pete Seeger
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Peter Pete Seeger was an American folk singer and social activist. Members of the Weavers were blacklisted during the McCarthy Era, in the 1960s, he re-emerged on the public scene as a prominent singer of protest music in support of international disarmament, civil rights, counterculture, and environmental causes. A prolific songwriter, his songs include Where Have All the Flowers Gone. If I Had a Hammer, and Turn, Turn. which have been recorded by many artists both in and outside the folk revival movement and are sung throughout the world. Flowers was a hit recording for the Kingston Trio, Marlene Dietrich, who recorded it in English, German and French, if I Had a Hammer was a hit for Peter, Paul and Mary and Trini Lopez while the Byrds had a number one hit with Turn. In the PBS American Masters episode Pete Seeger, The Power of Song, Seeger was born on May 3,1919, at the French Hospital, Midtown Manhattan. His Yankee-Protestant family, which Seeger called enormously Christian, in the Puritan, Calvinist New England tradition, Petes father, the Harvard-trained composer and musicologist Charles Louis Seeger, Jr. was born in Mexico City, Mexico, to American parents. Petes mother, Constance de Clyver, raised in Tunisia and trained at the Paris Conservatory of Music, was a concert violinist and later a teacher at the Juilliard School. In 1912, Charles Seeger was hired to establish the department at the University of California, Berkeley. Charles and Constance moved back east, making Charles parents estate in Patterson, New York, northeast of New York City, their base of operations. When baby Pete was eighteen months old they set out with him, upon their return, Constance taught violin and Charles taught composition at the New York Institute of Musical Art, whose president, family friend Frank Damrosch, was Constances adoptive uncle. Charles also taught part-time at the New School for Social Research, beginning in 1936, Charles held various administrative positions in the federal governments Farm Resettlement program, the WPAs Federal Music Project, and the wartime Pan American Union. After World War II, he taught ethnomusicology at the University of California, Petes uncle, Alan Seeger, a noted poet, had been one of the first American soldiers to be killed in World War I. All four of Petes half-siblings from his fathers second marriage – Margaret, Mike, Barbara, peggy Seeger, a well-known performer in her own right, married British folk singer and activist Ewan MacColl. Mike Seeger was a founder of the New Lost City Ramblers, one of members, John Cohen. Barbara Seeger joined her siblings in recording songs for children. In 1935, Pete attended Camp Rising Sun, a leadership camp held every summer in upstate New York that influenced his lifes work. He visited it most recently in 2012, in 1943, Pete married Toshi-Aline Ōta, whom he credited with being the support that helped make the rest of his life possible
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Sapric
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In the terminology of North American agriculture, muck is a soil made up primarily of humus from drained swampland. It is known as black soil in The Fens of eastern England and it is used there, as in the United States, for growing specialty crops such as onions, carrots, celery, and potatoes. Holland Marsh, north of Toronto, Ontario, is the site of the Muck Crops Research Station, a part of the University of Guelph. Muck farming on drained swamps is an important part of agriculture in New York, Ohio, Illinois, Indiana, Michigan, Wisconsin, and Florida, American muckers often have roots from the Netherlands or Eastern Europe, where their ancestors practiced a similar type of farming. The soils are deep, dark colored, and friable, often underlain by marl, or marly clay. The muckland of Torrey Farms of Elba, New York, which covers the counties of Orleans, Niagara, Muck farming is controversial, because the drainage of wetlands destroys wildlife habitats and results in a variety of environmental problems. It is unlikely that any more will be created in the United States, as the soil is very light, windbreaks are necessary to protect these fields in dry weather. It also can fire and burn underground for months. Oxidation also removes a portion of the each year, so it becomes progressively shallower. Some muck land has been reclaimed and restored as wetlands for wildlife preserves, the word muck has much usage in the English language, referring in some cases to agricultural soil, and in others to dirt in general, and animal dung in particular. Origins are probably from Norse, Danish, and Proto-Germanic roots referring to cow dung, black Beach, The Mucklands of Canastota, New York. The Horicon National Wildlife Refuge, established on land returned as much as possible to the original state An example of a typical muck farming operation
34.
National Geographic Society
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The National Geographic Society, headquartered in Washington, D. C. United States, is one of the largest nonprofit scientific and educational institutions in the world and its interests include geography, archaeology and natural science, the promotion of environmental and historical conservation, and the study of world culture and history. In partnership with 21st Century Fox, the Society operates the magazine, TV channels, a website that features extra content and worldwide events, the National Geographic Society was founded in 1888 to increase and diffuse geographic knowledge. The Society believes in the power of science, exploration and storytelling to change the world, National Geographic is governed by a board of trustees, whose 21 members include distinguished educators, business executives, former government officials and conservationists. The organization sponsors and funds research and exploration. National Geographic maintains a museum for the public in its Washington and its Education Foundation gives grants to education organizations and individuals to improve geography education. Its Committee for Research and Exploration has awarded more than 11,000 grants for scientific research, National Geographic has retail stores in Washington, D. C. The locations outside of the United States are operated by Worldwide Retail Store S. L and it also publishes other magazines, books, school products, maps, and Web and film products in numerous languages and countries. National Geographics various media properties reach more than 280 million people monthly, the National Geographic Society began as a club for an elite group of academics and wealthy patrons interested in travel. After preparing a constitution and a plan of organization, the National Geographic Society was incorporated two weeks later on January 27, Gardiner Greene Hubbard became its first president and his son-in-law, Alexander Graham Bell, succeeded him in 1897. Bell and Gilbert Hovey Grosvenor devised the successful marketing notion of Society membership, the current National Geographic Society president and CEO is Gary E. Knell. The chairman of the board of trustees is John Fahey, the editor-in-chief of National Geographic magazine is Susan Goldberg. Gilbert Melville Grosvenor, a chairman of the Society board of trustees received the Presidential Medal of Freedom in 2005 for his leadership in geography education. In 2004, the National Geographic Society headquarters in Washington, D. C. was one of the first buildings to receive a Green certification from Global Green USA. The National Geographic received the prestigious Prince of Asturias Award for Communication and Humanities in October 2006 in Oviedo, in 2013 the society was investigated for possible violation of the Foreign Corrupt Practices Act relating to their close association with an Egyptian government official responsible for antiquities. This new, for-profit corporation, will own National Geographic and other magazines, as reported by The Guardian, a spokesman for National Geographic in a November 2,2015 e-mail statement, briefly discussed the rationale for the staff reductions as part of the. Process of reorganizing in order to move forward following the closing the National Geographic Partners deal. Additional specifics were provided to Photo District News by M. J. Jacobsen, National Geographic’s SVP of communications, similar to the contents of a formal announcement by the two companies
35.
Discovery Channel
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Discovery Channel is an American basic cable and satellite television channel that is the flagship television property of Discovery Communications, a publicly traded company run by CEO David Zaslav. S. Flagship channel and its various owned or licensed television channels internationally, programming on the flagship Discovery Channel in the U. S. A popular annual feature on the channel is Shark Week, which airs on Discovery during the summer months, as of February 2015, Discovery Channel is available to approximately 96,589,000 pay television households in the United States. John Hendricks founded the channel and its parent company, Cable Educational Network Inc. in 1982, several investors raised $5 million in start-up capital to launch the network. The Discovery Channel began broadcasting on June 17,1985 and it was initially available to 156,000 households and broadcast for 12 hours each day between 3 p. m. and 3 a. m. About 75 percent of its content had never been broadcast on U. S. television before. In its early years, the focus centered on educational programming in the form of cultural and wildlife documentaries. It also broadcast some Soviet programming during this time, including the news program Vremya, in 1988, the channel premiered the nightly program World Monitor. By 1990, the channel was available in over 50 million households, the drop in viewership was widely attributed to an over-reliance on a few hit series, such as Monster Garage and American Chopper. Some critics said such shows strayed from Discoverys intention of providing more educationally based shows aimed at helping viewers learn about the world around them, in 2005, Discovery changed its programming focus to include more popular science and historical themes. The networks ratings eventually recovered in 2006, the network was nominated for seven Primetime Emmy Awards that year for shows including The Flight that Fought Back and Deadliest Catch. In 2007, Discovery Channels top series included the Emmy Award- and Peabody Award-winning Planet Earth, Dirty Jobs, MythBusters, Discovery Channels 2008 lineup included Fight Quest and Smash Lab. On September 1,2010, 43-year-old James Jay Lee entered the Discovery Communications headquarters in Silver Spring, Maryland, Lee fired at least one shot and held several employees hostage, he was later shot dead by police. Lee had published criticisms of the network at Savetheplanetprotest. com, in December 2015, Discovery Communications launched its TV Everywhere service, Discovery Go, which features live and video-on-demand content from Discovery Channel and eight of its sister networks. Popular programs on the channel have included the Shark Week programming event, Deadliest Catch, MythBusters, How Its Made, Dirty Jobs, Cash Cab, Christopher Lowell won a Daytime Emmy Award in 2000 for The Christopher Lowell Show. After the 2007 victory with the Spaniard Alberto Contador, Discovery Channel discontinued the cycling sponsorship, Discovery Channel Radio was a radio network, whose programming consisted of audio versions of popular programs from the Discovery Communications family of television channels. Discovery Channel Radio was previously carried by XM Satellite Radio, until its removal from the provider in early September 2005, sirius Satellite Radio dropped Discovery Radio from its lineup on February 21,2007, it was also carried on both of Canadas major satellite radio services. Discovery Channel lent its brand to stores in malls and other locations across America
36.
MythBusters
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MythBusters is a science entertainment television program created by Peter Rees and produced by Australias Beyond Television Productions. The series premiered on the Discovery Channel on January 23,2003, the series was transmitted by numerous international broadcasters, including SBS Australia, and other Discovery channels worldwide. The show was one of the oldest—and the most popular—on Discovery Channel, being preceded only by How Its Made and Daily Planet, from 2006 to 2016, the show was overseen by British show-runner Dan Tapster, working out of Sydney, San Francisco and Manchester. Filmed in San Francisco and edited in Artarmon, New South Wales, Australia, during the second season, members of Savage and Hynemans behind-the-scenes team were organized into a second team of MythBusters. They generally tested myths separately from the duo and operated from another workshop. On October 21,2015, it was announced that MythBusters would air its 14th, the show aired its final episode on March 6,2016. On March 25, Discoverys sister network, Science, announced its intention of continuing the series with new hosts, the show, currently airing, is titled Mythbusters, The Search. Adam Savage has confirmed that he and his former cohosts have no intentions of reuniting for future team projects, MythBusters refers both to the name of the documentary and also the cast members who test the experiments. The series concept was created for the Discovery Channel as Tall Tales or True by Australian writer and producer Peter Rees of Beyond Productions in 2002, Discovery rejected the proposal initially because they had just commissioned a series on the same topic. Rees refined the pitch to focus on testing key elements of the rather than just retelling them. Discovery agreed to develop and co-produce a three-episode series pilot, Jamie Hyneman was one of a number of special effects artists who were asked to prepare a casting video for network consideration. Rees had interviewed him previously for a segment of the science series Beyond 2000 about the British/American robot combat television series Robot Wars. The highest rated regular episode featured two stories, straw through a tree, and talking to plants. The highest rated two hour special was Hollywood Myths, the highest rated Shark Week special was Jaws Myths which screened in 2005. During July 2006, an edited version of MythBusters began airing on BBC Two in the UK. The episodes shown on the European Discovery Channel sometimes include extra scenes not shown in the United States version, the 14th season, which premiered in January 2016, was the final season for the series. Adam Savage and Jamie Hyneman are the original MythBusters, and initially explored all the myths of the series using their experience with special effects. The two work at Hynemans effects workshop, M5 Industries, they use of his staff
