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Plume (fluid Dynamics)
In hydrodynamics, a plume or a column is a vertical body of one fluid moving through another. Several effects control the motion of the fluid, including momentum (inertia), diffusion and buoyancy (density differences). Pure '' jets'' and pure ''plumes'' define flows that are driven entirely by momentum and buoyancy effects, respectively. Flows between these two limits are usually described as forced plumes or buoyant jets. "Buoyancy is defined as being positive" when, in the absence of other forces or initial motion, the entering fluid would tend to rise. Situations where the density of the plume fluid is greater than its surroundings (i.e. in still conditions, its natural tendency would be to sink), but the flow has sufficient initial momentum to carry it some distance vertically, are described as being negatively buoyant. Movement Usually, as a plume moves away from its source, it widens because of entrainment of the surrounding fluid at its edges. Plume shapes can be influenced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defense
Defense or defence may refer to: Tactical, martial, and political acts or groups * Defense (military), forces primarily intended for warfare * Civil defense, the organizing of civilians to deal with emergencies or enemy attacks * Defense industry, industry which manufactures and sells weapons and military technology * Self-defense, the use of force to defend oneself * Haganah (Hebrew for "The Defence"), a paramilitary organization in British Palestine * National security, security of a nation state, its citizens, economy, and institutions, as a duty of government ** Defence diplomacy, pursuit of foreign policy objectives through the peaceful employment of defence resources ** Ministry of defence or department of defense, a part of government which regulates the armed forces ** Defence minister, a cabinet position in charge of a ministry of defense * International security, measures taken by states and international organizations to ensure mutual survival and safety Sports * Defe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetary Atmosphere
Planetary means relating to a planet or planets. It can also refer to: Science * Planetary habitability, the measure of an astronomical body's potential to develop and sustain life * Planetary nebula, an astronomical object People * Planetary (rapper), one half of east coast rap group OuterSpace Arts, entertainment, and media * ''Planetary'' (comics), a comic book series by Warren Ellis and John Cassaday * "Planetary (Go!)", a 2011 song by rock band My Chemical Romance * ''Planetary Radio'', a public radio show about space exploration, produced by The Planetary Society Organizations * The Planetary Society, the Earth's largest space interest group Technology * Epicyclic gearing An epicyclic gear train (also known as a planetary gearset) is a gear reduction assembly consisting of two gears mounted so that the center of one gear (the "planet") revolves around the center of the other (the "sun"). A carrier connects the ... (planetary gearing), an automotive transmission te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stewart Turner
John Stewart Turner, FAA, FRS (11 January 1930 – 3 July 2022) was an Australian geophysicist. Early life Stewart Turner was educated at North Sydney Boys High School and Sydney University. He then joined the Cloud Physics Group, CSIRO Division of Radiophysics as a Research Officer. He was awarded the 1851 Exhibition Scholarship to University of Cambridge. Cambridge Turner completed his PhD thesis at University of Cambridge, Cambridge University in 1956 under the supervision of G. I. Taylor, Sir G.I. Taylor. His thesis title was "''Dynamical aspects of cloud physics''". A section of this work on cloud formation contributed to the 2nd paper in the first issue of The Journal of Fluid Mechanics His contemporaries in the laboratory included Owen Philips, Harold Grant and Philip Saffman. The work on cloud formation had application to clouds formed by nuclear explosion clouds. This work was contemporary with the British nuclear tests at Maralinga, Maralinga tests being carried out ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bruce Morton (mathematician)
Bruce Morton (11 April 1926 – 15 September 2012) was an Australian/New Zealand applied mathematician. Early life and education Morton was born in Wellington, New Zealand and educated at Auckland Grammar School. He gained a government scholarship to attend the University of Auckland, where he completed a double degree in mathematics and physics.Smith, Roger; Manton, Michael and Reeder, Michael. (2012)Mathematician an inspired lecturer and team builder''The Sydney Morning Herald'' Whilst at the University of Auckland he was an active member of the mountaineering club and climbed with Edmund Hillary. In 1949, Morton was awarded the Rutherford fellowship to study for a BA mathematical tripos at St John's College, Cambridge. Cambridge In 1956 he completed his PhD in the Department of Applied Mathematics and Theoretical Physics (DAMPT) at Cambridge University under the supervision of Sir G.I. Taylor and Sir George Batchelor. His thesis work was published in paper that became ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Expansion
Thermal expansion is the tendency of matter to increase in length, area, or volume, changing its size and density, in response to an increase in temperature (usually excluding phase transitions). Substances usually contract with decreasing temperature (thermal contraction), with rare exceptions within limited temperature ranges ('' negative thermal expansion''). Temperature is a monotonic function of the average molecular kinetic energy of a substance. As energy in particles increases, they start moving faster and faster, weakening the intermolecular forces between them and therefore expanding the substance. When a substance is heated, molecules begin to vibrate and move more, usually creating more distance between themselves. The relative expansion (also called strain) divided by the change in temperature is called the material's coefficient of linear thermal expansion and generally varies with temperature. Prediction If an equation of state is available, it can be used t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Pollution
Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles like soot and dust. It affects both outdoor air and indoor air. Natural sources of air pollution include Wildfire, wildfires, Dust storm, dust storms, and Volcanic eruption, volcanic eruptions. Indoor air pollution is often Energy poverty and cooking, caused by the use of biomass (e.g. wood) for cooking and heating. Outdoor air pollution comes from some industrial processes, the burning of Fossil fuel, fossil fuels for electricity and transport, waste management and agriculture. Many of the contributors of local air pollution, especially the burning of fossil fuels, also cause greenhouse gas emissions that cause climate change, global warming. Air pollution causes around 7 or 8 million deaths each year. It is a significant risk factor for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Dispersion Modelling
Atmospheric dispersion modeling is the mathematical simulation of how air pollutants disperse in the ambient atmosphere. It is performed with computer programs that include algorithms to solve the mathematical equations that govern the pollutant dispersion. The dispersion models are used to estimate the downwind ambient concentration of air pollutants or toxins emitted from sources such as industrial plants, vehicular traffic or accidental chemical releases. They can also be used to predict future concentrations under specific scenarios (i.e. changes in emission sources). Therefore, they are the dominant type of model used in air quality policy making. They are most useful for pollutants that are dispersed over large distances and that may react in the atmosphere. For pollutants that have a very high spatio-temporal variability (i.e. have very steep distance to source decay such as black carbon) and for epidemiological studies statistical land-use regression models are also use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Pollution
Water pollution (or aquatic pollution) is the contamination of Body of water, water bodies, with a negative impact on their uses. It is usually a result of human activities. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water pollution results when contaminants mix with these water bodies. Contaminants can come from one of four main sources. These are sewage discharges, industrial activities, agricultural activities, and urban runoff including stormwater. Water pollution may affect either surface water or groundwater pollution, groundwater. This form of pollution can lead to many problems. One is the environmental degradation, degradation of aquatic ecosystems. Another is spreading Waterborne diseases, water-borne diseases when people use polluted water for drinking or irrigation. Water pollution also reduces the ecosystem services such as drinking water provided by the Water resources, water resource. Sources of water pollution are either p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquifer
An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The study of water flow in aquifers and the characterization of aquifers is called ''hydrogeology''. Related concepts include aquitard, a bed (geology), bed of low permeability along an aquifer, and aquiclude (or ''aquifuge''), a solid and impermeable region underlying or overlying an aquifer, the pressure of which could lead to the formation of a confined aquifer. Aquifers can be classified as saturated versus unsaturated; aquifers versus aquitards; confined versus unconfined; isotropic versus anisotropic; porous, karst, or fractured; and transboundary aquifer. Groundwater from aquifers can be sustainably harvested by humans through the use of qanats leading to a well. This groundwater is a major source of fresh water for many regions, althoug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater Pollution
Groundwater pollution (also called groundwater contamination) occurs when pollutants are released to the ground and make their way into groundwater. This type of water pollution can also occur naturally due to the presence of a minor and unwanted constituent, contaminant, or impurity in the groundwater, in which case it is more likely referred to as contamination rather than pollution. Groundwater pollution can occur from on-site sanitation systems, landfill leachate, effluent from wastewater treatment plants, leaking sewers, petrol filling stations, hydraulic fracturing (fracking) or from over application of fertilizers in agriculture. Pollution (or contamination) can also occur from naturally occurring contaminants, such as arsenic contamination of groundwater, arsenic or fluoride. Using polluted groundwater causes hazards to public health through poisoning or the spread of disease (Waterborne diseases, water-borne diseases). The pollutant often produces a contaminant Plume (f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater
Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit of rock or an unconsolidated deposit is called an ''aquifer'' when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the ''water table''. Groundwater is Groundwater recharge, recharged from the surface; it may discharge from the surface naturally at spring (hydrosphere), springs and Seep (hydrology), seeps, and can form oasis, oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction water well, wells. The study of the distribution and movement of groundwater is ''hydrogeology'', also called groundwater hydrology. Typically, groundwater is thought o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
