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Fouling
Fouling is the accumulation of unwanted material on solid surfaces. The fouling materials can consist of either living organisms (biofouling, organic) or a non-living substance (inorganic). Fouling is usually distinguished from other surface-growth phenomena in that it occurs on a surface of a component, system, or plant performing a defined and useful function and that the fouling process impedes or interferes with this function. Other terms used in the literature to describe fouling include deposit formation, encrustation, crudding, deposition, scaling, scale formation, slagging, and sludge formation. The last six terms have a more narrow meaning than fouling within the scope of the fouling science and technology, and they also have meanings outside of this scope; therefore, they should be used with caution. Fouling phenomena are common and diverse, ranging from fouling of ship hulls, natural surfaces in the marine environment (fouling community, marine fouling), fouling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membrane Fouling
Membrane fouling is a process whereby a solution or a particle is deposited on a membrane surface or in membrane pores in a processes such as in a membrane bioreactor, reverse osmosis, forward osmosis, membrane distillation, ultrafiltration, microfiltration, or nanofiltration so that the membrane's performance is degraded. It is a major obstacle to the widespread use of this technology. Membrane fouling can cause severe flux decline and affect the quality of the water produced. Severe fouling may require intense chemical cleaning or membrane replacement. This increases the operating costs of a treatment plant. There are various types of foulants: colloidal (clays, flocs), biological (bacteria, fungi), organic (oils, polyelectrolytes, humics) and scaling (mineral precipitates). Fouling can be divided into reversible and irreversible fouling based on the attachment strength of particles to the membrane surface. Reversible fouling can be removed by a strong shear force or backwashi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fouling Community
Fouling communities are communities of organisms found on artificial surfaces like the sides of docks, marinas, harbors, and boats. Settlement panels made from a variety of substances have been used to monitor settlement patterns and to examine several community processes (e.g., succession, recruitment, predation, competition, and invasion resistance). These communities are characterized by the presence of a variety of sessile organisms including ascidians, bryozoans, mussels, tube building polychaetes, sea anemones, sponges, barnacles, and more. Common predators on and around fouling communities include small crabs, starfish, fish, limpets, chitons, other gastropods, and a variety of worms. Ecology Fouling communities follow a distinct succession pattern in a natural environment. Environmental impact Impacts on Humans Fouling communities can have a negative economic impact on humans, by damaging the bottom of boats, docks, and other marine human-made structures. This e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biofouling
Biofouling or biological fouling is the accumulation of microorganisms, plants, algae, or small animals where it is not wanted on surfaces such as ship and submarine hulls, devices such as water inlets, pipework, grates, ponds, and rivers that cause degradation to the primary purpose of that item. Such accumulation is referred to as '' epibiosis'' when the host surface is another organism and the relationship is not parasitic. Since biofouling can occur almost anywhere water is present, biofouling poses risks to a wide variety of objects such as boat hulls and equipment, medical devices and membranes, as well as to entire industries, such as paper manufacturing, food processing, underwater construction, and desalination plants. Anti-fouling is the ability of specifically designed materials (such as toxic biocide paints, or non-toxic paints) to remove or prevent biofouling. The buildup of biofouling on marine vessels poses a significant problem. In some instances, the hull str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Exchanger
A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, Petrochemical, petrochemical plants, Oil refinery, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air. Another example is the heat sink, which is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant. Flow arrangement There are three primary classifications of heat exchangers accord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calculus (dental)
In dentistry, calculus or tartar is a form of hardened dental plaque. It is caused by precipitation of minerals from saliva and Gingival sulcus, gingival crevicular fluid (GCF) in plaque on the teeth. This process of precipitation kills the bacterial cells within dental plaque, but the rough and hardened surface that is formed provides an ideal surface for further plaque formation. This leads to calculus buildup, which compromises the health of the gingiva (gums). Calculus can form both along the gumline, where it is referred to as supragingival (), and within the narrow Sulcus (morphology), sulcus that exists between the teeth and the gingiva, where it is referred to as subgingival (). Calculus formation is associated with a number of clinical manifestations, including halitosis, bad breath, receding gums and Chronic (medicine), chronically inflamed gingiva. Brushing and flossing can remove plaque from which calculus forms; however, once formed, calculus is too hard (firmly att ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scaling01
Scaling may refer to: Science and technology Mathematics and physics * Scaling (geometry), a linear transformation that enlarges or diminishes objects * Scale invariance, a feature of objects or laws that do not change if scales of length, energy, or other variables are multiplied by a common factor ** Scaling law, a law that describes the scale invariance found in many natural phenomena * The scaling of critical exponents in physics, such as Widom scaling, or scaling of the renormalization group Computing and information technology * Feature scaling, a method used to standardize the range of independent variables or features of data * Image scaling, the resizing of an image * Multidimensional scaling, a means of visualizing the level of similarity of individual cases of a dataset * Scalability, a computer or network's ability to function as the amount of data or number of users increases * Scaling along the Z axis, a technique used in computer graphics for a pseudo-3D effect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extraction Of Petroleum
Petroleum is a fossil fuel that can be drawn from beneath the Earth's surface. Reservoirs of petroleum are formed through the mixture of plants, algae, and sediments in shallow seas under high pressure. Petroleum is mostly recovered from oil drilling. Seismic surveys and other methods are used to locate oil reservoirs. Oil rigs and oil platforms are used to drill long holes into the earth to create an oil well and extract petroleum. After extraction, oil is refined to make gasoline and other products such as tires and refrigerators. Extraction of petroleum can be dangerous and has led to oil spills. Locating the oil field Geologists and geophysicists use seismic surveys to search for geological structures that may form oil reservoirs. The "classic" method includes making an underground explosion nearby and observing the seismic response, which provides information about the geological structures underground. However, "passive" methods that extract information from naturall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petroleum Reservoir
A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations. Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presence of high heat and pressure in the Earth's crust. Reservoirs are broadly classified as ''conventional'' and '' unconventional'' reservoirs. In conventional reservoirs, the naturally occurring hydrocarbons, such as crude oil (petroleum) or natural gas, are trapped by overlying rock formations with lower permeability, while in unconventional reservoirs the rocks have high porosity and low permeability, which keeps the hydrocarbons trapped in place, therefore not requiring a cap rock. Reservoirs are found using hydrocarbon exploration methods. Oil field An oil field is an area of accumulated liquid petroleum underground in multiple (potentially linked) reservoirs, trapped as it rises to impermeable rock formations. In industrial te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oil Well
An oil well is a drillhole boring in Earth that is designed to bring petroleum oil hydrocarbons to the surface. Usually some natural gas is released as associated petroleum gas along with the oil. A well that is designed to produce only gas may be termed a gas well. Wells are created by drilling down into an oil or gas reserve and if necessary equipped with extraction devices such as pumpjacks. Creating the wells can be an expensive process, costing at least hundreds of thousands of dollars, and costing much more when in difficult-to-access locations, e.g., offshore. The process of modern drilling for wells first started in the 19th century but was made more efficient with advances to oil drilling rigs and technology during the 20th century. Wells are frequently sold or exchanged between different oil and gas companies as an asset – in large part because during falls in the price of oil and gas, a well may be unproductive, but if prices rise, even low-production wells may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
