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Fan (mechanical)
A fan is a powered machine used to create a flow of air. A fan consists of a rotating arrangement of vanes or blades, generally made of wood, plastic, or metal, which act on the air. The rotating assembly of blades and hub is known as an ''impeller'', ''rotor'', or ''runner''. Usually, it is contained within some form of housing, or case. This may direct the airflow, or increase safety by preventing objects from contacting the fan blades. Most fans are powered by electric motors, but other sources of power may be used, including hydraulic motors, handcranks, and internal combustion engines. Mechanically, a fan can be any revolving vane, or vanes used for producing currents of air. Fans produce air flows with high volume and low pressure (although higher than ambient pressure), as opposed to compressors which produce high pressures at a comparatively low volume. A fan blade will often rotate when exposed to an air-fluid stream, and devices that take advantage of this, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quat
Quat may refer to: * Quat (surname), a Chinese surname * Quaternary ammonium cation, a class of chemical molecules used as a disinfectant, surfactant, drug etc. * Quaternion, a non-commutative extension of the complex numbers * Quaternary (other), referring to four parts, divisions, or sets. * Khat Khat or qat ( ''ch’at''; Oromo: ''Jimaa'', so, qaad, khaad, khat or chat, ar, القات ''al-qāt'') is a flowering plant native to eastern and southern Africa. Khat contains the alkaloid cathinone, a stimulant, which is said to cause ..., an African plant whose leaves are chewed as a stimulant * Phan Huy Quát, former prime minister of South Vietnam {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambient Pressure
Ambient or Ambiance or Ambience may refer to: Music and sound * Ambience (sound recording), also known as atmospheres or backgrounds * Ambient music Ambient music is a genre of music that emphasizes tone and atmosphere over traditional musical structure or rhythm. It may lack net composition, beat, or structured melody.The Ambient Century by Mark Prendergast, Bloomsbury, London, 2003. It ..., a genre of music that puts an emphasis on tone and atmosphere * ''Ambient'' (album), by Moby * ''Ambience'' (album), by the Lambrettas * Virgin Ambient series, a series of 24 albums released on the UK Virgin Records label between 1993 and 1997 *''Ambient 1–4'', a set of four albums by Brian Eno, released by Obscure Records between 1978 and 1982 Other * Ambient (computation), a process calculus * Ambient (desktop environment), a MUI-based desktop environment for MorphOS * ''Ambient'' (novel), a novel by Jack Womack * Mark Ambient (1860–1937), pen name of Harold Harley, Engli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire
Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. At a certain point in the combustion reaction, called the ignition point, flames are produced. The ''flame'' is the visible portion of the fire. Flames consist primarily of carbon dioxide, water vapor, oxygen and nitrogen. If hot enough, the gases may become ionized to produce Plasma (physics), plasma. Depending on the substances alight, and any impurities outside, the color of the flame and the fire's Intensity (heat transfer), intensity will be different. Fire in its most common form can result in conflagration, which has the potential to cause physical damage through burning. Fire is an important process that affects ecological systems around the globe. The positive effects of fire include stimulating growth and maintaining various ecological systems. Its negative effects include hazard to life and pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum Cleaner
A vacuum cleaner, also known simply as a vacuum or a hoover, is a device that causes suction in order to remove dirt from floors, upholstery, draperies, and other surfaces. It is generally electrically driven. The dirt is collected by either a dustbag or a cyclone for later disposal. Vacuum cleaners, which are used in homes as well as in industry, exist in a variety of sizes and models—small battery-powered hand-held devices, wheeled canister models for home use, domestic central vacuum cleaners, huge stationary industrial appliances that can handle several hundred litres of dirt before being emptied, and self-propelled vacuum trucks for recovery of large spills or removal of contaminated soil. Specialized shop vacuums can be used to suck up both solid matter and liquids. Name Although ''vacuum cleaner'' and the short form ''vacuum'' are neutral names, in some countries (UK, Ireland) ''hoover'' is used instead as a genericized trademark, and as a verb. The name comes from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sucking
Suction is the colloquial term to describe the air pressure differential between areas. Removing air from a space results in a pressure differential. Suction pressure is therefore limited by external air pressure. Even a perfect vacuum cannot suck with more pressure than is available in the surrounding environment. Suctions can form on the sea, for example, when a ship founders. When the pressure in one part of a physical system is reduced relative to another, the fluid in the higher pressure region will exert a force relative to the region of lowered pressure, referred to as pressure-gradient force. Pressure reduction may be static, as in a piston and cylinder arrangement, or dynamic, as in the case of a vacuum cleaner when air flow results in a reduced pressure region. When animals breathe, the diaphragm and muscles around the rib cage cause a change of volume in the lungs. The increased volume of the chest cavity decreases the pressure inside, creating an imbalance with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dust
Dust is made of fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian process), volcanic eruptions, and pollution. Dust in homes is composed of about 20–50% dead skin cells. The rest, and in offices, and other human environments is composed of small amounts of plant pollen, human hairs, animal fur, textile fibers, paper fibers, minerals from outdoor soil, burnt meteorite particles, and many other materials which may be found in the local environment. Atmospheric Atmospheric or wind-borne fugitive dust, also known as ''aeolian dust'', comes from arid and dry regions where high velocity winds are able to remove mostly silt-sized material, deflating susceptible surfaces. This includes areas where grazing, ploughing, vehicle use, and other human behaviors have further destabilized the land, though not all source areas have been largely affected by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cereal
A cereal is any grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, germ, and bran. Cereal grain crops are grown in greater quantities and provide more food energy worldwide than any other type of crop and are therefore staple crops. They include wheat, rye, oats, and barley. Edible grains from other plant families, such as buckwheat, quinoa and chia, are referred to as pseudocereals. In their unprocessed whole grain form, cereals are a rich source of vitamins, minerals, carbohydrates, fats, oils, and protein. When processed by the removal of the bran and germ the remaining endosperm is mostly carbohydrate. In some developing countries, grain in the form of rice, wheat, millet, or maize constitutes a majority of daily sustenance. In developed countries, cereal consumption is moderate and varied but still substantial, primarily in the form of refined and processed grains. Because of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winnowing
Winnowing is a process by which chaff is separated from grain. It can also be used to remove pests from stored grain. Winnowing usually follows threshing in grain preparation. In its simplest form, it involves throwing the mixture into the air so that the wind blows away the lighter chaff, while the heavier grains fall back down for recovery. Techniques included using a winnowing fan (a shaped basket shaken to raise the chaff) or using a tool (a winnowing fork or shovel) on a pile of harvested grain. In Greek culture The winnowing-fan (λίκνον 'líknon'' also meaning a "cradle") featured in the rites accorded Dionysus and in the Eleusinian Mysteries: "it was a simple agricultural implement taken over and mysticized by the religion of Dionysus," Jane Ellen Harrison remarked. ''Dionysus Liknites'' ("Dionysus of the winnowing fan") was wakened by the Dionysian women, in this instance called '' Thyiades'', in a cave on Parnassus high above Delphi; the winnowing-fan lin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Power Amplifier
An audio power amplifier (or power amp) is an electronic amplifier that amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup, to a level that is high enough for driving loudspeakers or headphones. Audio power amplifiers are found in all manner of sound systems including sound reinforcement, public address and home audio systems and musical instrument amplifiers like guitar amplifiers. It is the final electronic stage in a typical audio playback chain before the signal is sent to the loudspeakers. The preceding stages in such a chain are low power audio amplifiers which perform tasks like pre-amplification of the signal (this is particularly associated with record turntable signals, microphone signals and electric instrument signals from pickups, such as the electric guitar and electric bass), equalization (e.g., adjusting the bass and treble), tone controls, mixing different input signals or adding elec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiator
Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics. A radiator is always a source of heat to its environment, although this may be for either the purpose of heating this environment, or for cooling the fluid or coolant supplied to it, as for automotive engine cooling and HVAC dry cooling towers. Despite the name, most radiators transfer the bulk of their heat via convection instead of thermal radiation. History The Roman hypocaust is an early example of a type of radiator for building space heating. Franz San Galli, a Prussian-born Russian businessman living in St. Petersburg, is credited with inventing the heating radiator around 1855, having received a radiator patent in 1857, but American Joseph Nason developed a primitive radiator in 1841 and received a number of U.S. patents for hot water and steam he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Comfort
Thermal comfort is the condition of mind that expresses satisfaction with the thermal environment and is assessed by subjective evaluation ( ANSI/ASHRAE Standard 55).ANSI/ASHRAE Standard 55-2017, Thermal Environmental Conditions for Human Occupancy The human body can be viewed as a heat engine where food is the input energy. The human body will release excess heat into the environment, so the body can continue to operate. The heat transfer is proportional to temperature difference. In cold environments, the body loses more heat to the environment and in hot environments the body does not release enough heat. Both the hot and cold scenarios lead to discomfort. Maintaining this standard of thermal comfort for occupants of buildings or other enclosures is one of the important goals of HVAC (heating, ventilation, and air conditioning) design engineers. Thermal neutrality is maintained when the heat generated by human metabolism is allowed to dissipate, thus maintaining thermal equili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HVAC
Heating, ventilation, and air conditioning (HVAC) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. " Refrigeration" is sometimes added to the field's abbreviation as HVAC&R or HVACR, or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers). HVAC is an important part of residential structures such as single family homes, apartment buildings, hotels, and senior living facilities; medium to large industrial and office buildings such as skyscrapers and hospitals; vehicles such as cars, trains, airplanes, ships and submarines; and in marine environments, where safe and healthy building conditions are regulated with respect to temperature and humidity, using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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