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Duct Plate
The word duct is derived from the Latin word for ''led/leading''. It may refer to: * Duct (anatomy), various ducts in anatomy and physiology ** Tear duct, which carry tears to the eyes * Duct (HVAC), for transfer of air between spaces in a structure * Duct tape, a kind of adhesive tape * Ducted fan, motor for aircraft * Electrical bus duct, a metal enclosure for busbars * Duct (industrial exhaust), industrial exhaust duct system designed for low pressure-pneumatic convey of gas, fumes, dusts, shavings, and other pollutants from works space to atmosphere after cleaning and removal of contaminants * Atmospheric duct, a horizontal layer in the lower atmosphere in which the vertical refractive index gradients are such that radio signals (a) are guided or ducted, (b) tend to follow the curvature of the Earth, and (c) experience less attenuation in the ducts than they would if the ducts were not present ** Tropospheric ducting, a type of radio propagation in the troposphere that allows s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duct (anatomy)
In anatomy and physiology, a duct is a circumscribed channel leading from an exocrine gland or organ. Types of ducts Examples include: Duct system As ducts travel from the acinus which generates the fluid to the target, the ducts become larger and the epithelium becomes thicker. The parts of the system are classified as follows: Some sources consider "lobar" ducts to be the same as "interlobar ducts", while others consider lobar ducts to be larger and more distal from the acinus. For sources that make the distinction, the interlobar ducts are more likely to classified with simple columnar epithelium (or pseudostratified epithelium), reserving the stratified columnar for the lobar ducts. File:Gray1025.png, Section of submaxillary gland of kitten. Duct semidiagrammatic. X 200. File:Gray1173.png, Section of portion of mamma. Intercalated duct The intercalated duct, also called intercalary duct (ducts of Boll), is the portion of an exocrine gland leading directly from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tear Duct
The nasolacrimal duct (also called the tear duct) carries tears from the lacrimal sac of the eye into the nasal cavity. The duct begins in the eye socket between the maxillary and lacrimal bones, from where it passes downwards and backwards. The opening of the nasolacrimal duct into the inferior nasal meatus of the nasal cavity is partially covered by a mucosal fold ( valve of Hasner or ''plica lacrimalis''). Excess tears flow through the nasolacrimal duct which drains into the inferior nasal meatus. This is the reason the nose starts to run when a person is crying or has watery eyes from an allergy, and why one can sometimes taste eye drops. This is for the same reason when applying some eye drops it is often advised to close the nasolacrimal duct by pressing it with a finger to prevent the medicine from escaping the eye and having unwanted side effects elsewhere in the body as it will proceed through the canal to the Nasal Cavity. Like the lacrimal sac, the duct is lined by st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duct (HVAC)
Ducts are conduits or passages used in heating, ventilation, and air conditioning (HVAC) to deliver and remove air. The needed airflows include, for example, ''supply air'', ''return air'', and ''exhaust air''. Ducts commonly also deliver '' ventilation air'' as part of the supply air. As such, air ducts are one method of ensuring acceptable indoor air quality as well as thermal comfort. A duct system is also called ''ductwork''. Planning (laying out), sizing, optimizing, detailing, and finding the pressure losses through a duct system is called ''duct design''. Materials Ducts can be made out of the following materials: Galvanized steel Galvanized mild steel is the standard and most common material used in fabricating ductwork because the zinc coating of this metal prevents rusting and avoids cost of painting. For insulation purposes, metal ducts are typically lined with faced fiberglass blankets (duct liner) or wrapped externally with fiberglass blankets (duct wrap). When ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duct Tape
Duct tape (also called duck tape, from the cotton duck cloth it was originally made of) is cloth- or scrim-backed pressure-sensitive tape, often coated with polyethylene. There are a variety of constructions using different backings and adhesives, and the term 'duct tape' has been genericized to refer to different cloth tapes with differing purposes. A variation is heat-resistant foil tape useful for sealing heating and cooling ducts, produced because the adhesive on standard duct tape fails and the synthetic fabric reinforcement mesh deteriorates when used on heating ducts. Duct tape is generally silvery gray in color, but also available in other colors and printed designs, from whimsical yellow ducks, college logos to practical camouflage patterns. It is often confused with gaffer tape (which is designed to be non-reflective and cleanly removed, unlike duct tape). During World War II, Revolite (then a division of Johnson & Johnson) developed an adhesive tape made from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ducted Fan
In aeronautics, a ducted fan is a thrust-generating mechanical fan or propeller mounted within a cylindrical duct or shroud. Other terms include ducted propeller or shrouded propeller. When used in vertical takeoff and landing (VTOL) applications it is also known as a shrouded rotor.Kotwani, Kailash;Ducted Fan or Shrouded Rotor Aerodynamics and its Application in Miniature VTOL Aerial Vehicles, 2009. (retrieved 22 March 2022). Ducted fans are used for propulsion or direct lift in many types of vehicle including aeroplanes, airships, hovercraft, and powered lift VTOL aircraft. The high-bypass turbofan engines used on many modern airliners is an example of a very successful and popular use of ducted fan design. The duct increases thrust efficiency by up to 90% in some cases, in comparison to a similar-sized propeller in free air. Ducted fans are quieter, and offer good opportunities for thrust vectoring. The shroud offers good protection to ground personnel from accidentally cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Busbar
In electric power distribution, a busbar (also bus bar) is a metallic strip or bar, typically housed inside switchgear, panel boards, and busway enclosures for local high current power distribution. They are also used to connect high voltage equipment at electrical switchyards, and low voltage equipment in battery banks. They are generally uninsulated, and have sufficient stiffness to be supported in air by insulated pillars. These features allow sufficient cooling of the conductors, and the ability to tap in at various points without creating a new joint. Design and placement The busbar's material composition and cross-sectional size determine the maximum current it can safely carry. Busbars can have a cross-sectional area of as little as , but electrical substations may use metal tubes in diameter () or more as busbars. Aluminium smelters use very large busbars to carry tens of thousands of amperes to the electrochemical cells that produce aluminium from molten salts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duct (industrial Exhaust)
Industrial exhaust ducts are pipe systems that connect hoods to industrial chimneys through other components of exhaust systems like fans, collectors, etc. Ducts are low-pressure pneumatic conveyors to convey dust, particles, shavings, fumes, or chemical hazardous components from air in the vicinity to a shop floor or any other specific locations like tanks, sanding machines, or laboratory hoods. Ducts can be fabricated from a variety of materials including carbon steel, stainless steel, PVC, and fiberglass. They can be fabricated through rolling (preferable for ducts of 12" or more in diameter) or extruded (for ducts up to 18"). HVAC systems do not include this category of industrial application, namely exhaust systems. A distinction from HVAC system ducts is that the fluid (air) conveyed through the duct system may not be homogeneous. An industrial exhaust duct system is primarily a pneumatic conveying system and is basically governed by laws of flow of fluids. Fluid flow T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Duct
In telecommunications, an atmospheric duct is a horizontal layer in the lower atmosphere in which the vertical refractive index gradients are such that radio signals (and light rays) are guided or ducted, tend to follow the curvature of the Earth, and experience less attenuation in the ducts than they would if the ducts were not present. The duct acts as an atmospheric dielectric waveguide and limits the spread of the wavefront to only the horizontal dimension. Atmospheric ducting is a mode of propagation of electromagnetic radiation, usually in the lower layers of Earth’s atmosphere, where the waves are bent by atmospheric refraction. In over-the-horizon radar, ducting causes part of the radiated and target-reflection energy of a radar system to be guided over distances far greater than the normal radar range. It also causes long distance propagation of radio signals in bands that would normally be limited to line of sight. Normally radio "ground waves" propagate along the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tropospheric Ducting
Tropospheric propagation describes electromagnetic propagation in relation to the troposphere. The service area from a VHF or UHF radio transmitter extends to just beyond the horizon, optical horizon, at which point signals start to rapidly reduce in strength. Viewers living in such a "deep fringe" reception area will notice that during certain conditions, weak signals normally masked by noise increase in signal strength to allow quality reception. Such conditions are related to the current state of the troposphere. Tropospheric propagated signals travel in the part of the Earth's atmosphere, atmosphere adjacent to the surface and extending to some 7.5 km. Such signals are thus directly affected by weather conditions extending over hundreds of kilometres. During very settled, warm Cyclone, anticyclonic weather (i.e., high atmospheric pressure, pressure), usually weak signals from distant transmitters improve in strength. Another symptom during such conditions may be Interfere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth–ionosphere Waveguide
The Earth–ionosphere waveguide refers to the phenomenon in which certain radio waves can propagate in the space between the ground and the boundary of the ionosphere. Because the ionosphere contains charged particles, it can behave as a conductor. The earth operates as a ground plane, and the resulting cavity behaves as a large waveguide. Extremely low frequency (ELF) (< 3 kHz) and (VLF) (3–30 kHz) signals can propagate efficiently in this waveguide. For instance, lightning strikes launch a signal called , which can travel many thousands of kilometers, because they are confined between the Earth and the ionosphere. The round-the-world nature of the waveguide produces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Duct
Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects on or under the surface of the water, such as other vessels. "Sonar" can refer to one of two types of technology: ''passive'' sonar means listening for the sound made by vessels; ''active'' sonar means emitting pulses of sounds and listening for echoes. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water. Acoustic location in air was used before the introduction of radar. Sonar may also be used for robot navigation, and SODAR (an upward-looking in-air sonar) is used for atmospheric investigations. The term ''sonar'' is also used for the equipment used to generate and receive the sound. The acoustic frequencies used in sonar systems vary from very low ( infrasonic) to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Conduit
An electrical conduit is a tube used to protect and route electrical wiring in a building or structure. Electrical conduit may be made of metal, plastic, fiber, or fired clay. Most conduit is rigid, but flexible conduit is used for some purposes. Conduit is generally installed by electricians at the site of installation of electrical equipment. Its use, form, and installation details are often specified by wiring regulations, such as the US National Electrical Code (NEC) and other building codes. History Some early electric lighting installations made use of existing gas pipe serving gas light fixtures which had been converted to electric lamps. Since this technique provided very good mechanical protection for interior wiring, it was extended to all types of interior wiring and by the early 20th century purpose-built couplings and fittings were manufactured for electrical use. However, most electrical codes now prohibit the routing of electrical conductors through gas piping ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
