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Halbach Array
A Halbach array () is a special arrangement of permanent magnets that augments the magnetic field on one side of the array while cancelling the field to near zero on the other side. This is achieved by having a spatially rotating pattern of magnetisation. The rotating pattern of permanent magnets (on the front face; on the left, up, right, down) can be continued indefinitely and have the same effect. The effect of this arrangement is roughly similar to many horseshoe magnets placed adjacent to each other, with similar poles touching. This magnetic orientation process replicates that applied by a magnetic recording tape head to the magnetic tape coating during the recording process. The principle was further described by James (Jim) M. Winey of Magnepan in 1970, for the ideal case of continuously rotating magnetization, induced by a one-sided stripe-shaped coil. The effect was also discovered by John C. Mallinson in 1973, and these "one-sided flux" structures were initially desc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voice Coil
A voice coil (consisting of a former, collar, and winding) is the coil of wire attached to the apex of a loudspeaker cone. It provides the motive force to the cone by the reaction of a magnetic field to the current passing through it. The term is also used for voice coil linear motors such as those used to move the heads inside hard disk drives, which produce a larger force and move a longer distance but work on the same principle. In some applications, such as the operation of servo valves, electronic focus adjustment on digital cameras, these are known as voice coil motors (VCM). Operation By driving a current through the voice coil, a magnetic field is produced. This magnetic field causes the voice coil to react to the magnetic field from a permanent magnet fixed to the speaker's frame, thereby moving the cone of the speaker. By applying an audio waveform to the voice coil, the cone will reproduce the sound pressure waves, corresponding to the original input sig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wiggler Magnet
A wiggler is an insertion device in a synchrotron. It is a series of magnets designed to periodically laterally deflect ('wiggle') a beam of charged particles (invariably electrons or positrons) inside a storage ring of a synchrotron. These deflections create a change in acceleration which in turn produces emission of broad synchrotron radiation tangent to the curve, much like that of a bending magnet, but the intensity is higher due to the contribution of many magnetic dipoles in the wiggler. Furthermore, as the wavelength (λ) is decreased this means the frequency (ƒ) has increased. This increase of frequency is directly proportional to energy, hence, the wiggler creates a wavelength of light with a larger energy. A wiggler has a broader spectrum of radiation than an undulator. Typically the magnets in a wiggler are arranged in a Halbach array. The design shown above is usually known as a Halbach wiggler. History The first suggestion of a wiggler magnet to produce syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fridge Magnet Halbach
A refrigerator, commonly shortened to fridge, is a commercial and home appliance consisting of a thermally insulated compartment and a heat pump (mechanical, electronic or chemical) that transfers heat from its inside to its external environment so that its inside is cooled to a temperature below the room temperature. Refrigeration is an essential food storage technique around the world. The low temperature reduces the reproduction rate of bacteria, so the refrigerator lowers the rate of spoilage. A refrigerator maintains a temperature a few degrees above the freezing point of water. The optimal temperature range for perishable food storage is .Keep your fridge-freezer clean and ice-free ''BBC''. 30 April 2008 A freezer is a specialized refrigerator, or portion of a refrigerator, that maintains its contents’ temperature below the freezing point of water. The refrigerator replaced the icebox, which had been a common household appliance for almost a century and a half. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Viewing Film
Magnetic field viewing film is used to show stationary or (less often) slowly changing magnetic fields; it shows their location and direction. It is a translucent thin flexible sheet, coated with micro-capsules containing nickel flakes suspended in oil. When magnetic lines of force are parallel to the surface of the carrier sheet, the surfaces of the flakes are reflective, and appear bright. When lines of force are perpendicular to the sheet, the flakes are edge-on, and appear significantly darker. When the film is placed on a magnet's pole, the latter case applies. Magnetic field viewing film together with a ruler can be used to measure the poles per inch of a magnet. See also * Ferrofluid * Magna Doodle References External links Magnetic devices {{electromagnetism-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extrusion
Extrusion is a process used to create objects of a fixed cross section (geometry), cross-sectional profile by pushing material through a Die (manufacturing), die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex cross-sections; and to work materials that are brittle, because the material encounters only compressive stress, compressive and shear stress, shear stresses. It also creates excellent surface finish and gives considerable freedom of form in the design process. Drawing (manufacturing), Drawing is a similar process, using the tensile strength of the material to pull it through the die. It limits the amount of change that can be performed in one step, so it is limited to simpler shapes, and multiple stages are usually needed. Drawing is the main way to produce wire. Metal Bar stock, bars and tube (fluid conveyance), tubes are also often drawn. Extrusion may be continuous (theoretically producin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferromagnetic
Ferromagnetism is a property of certain materials (such as iron) that results in a significant, observable magnetic permeability, and in many cases, a significant magnetic coercivity, allowing the material to form a permanent magnet. Ferromagnetic materials are noticeably attracted to a magnet, which is a consequence of their substantial magnetic permeability. Magnetic permeability describes the induced magnetization of a material due to the presence of an external magnetic field. For example, this temporary magnetization inside a steel plate accounts for the plate's attraction to a magnet. Whether or not that steel plate then acquires permanent magnetization depends on both the strength of the applied field and on the coercivity of that particular piece of steel (which varies with the steel's chemical composition and any heat treatment it may have undergone). In physics, multiple types of material magnetism have been distinguished. Ferromagnetism (along with the similar effec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferrite (magnet)
A ferrite is one of a family of iron oxide-containing magnetic ceramic materials. They are ferrimagnetic, meaning they are attracted by magnetic fields and can be Magnetization, magnetized to become permanent magnets. Unlike many ferromagnetic materials, most ferrites are not electrically electrical conductor, conductive, making them useful in applications like magnetic cores for transformers to suppress eddy currents. Ferrites can be divided into two groups based on their magnetic coercivity, their resistance to being demagnetized: "Hard" ferrites have high coercivity, so are difficult to demagnetize. They are used to make permanent magnets for applications such as refrigerator magnets, loudspeakers, and small electric motors. "Soft" ferrites have low coercivity, so they easily change their magnetization and act as conductors of magnetic fields. They are used in the electronics industry to make efficient magnetic cores called ferrite cores for high-frequency inductors, transfo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Viewing Film
Magnetic field viewing film is used to show stationary or (less often) slowly changing magnetic fields; it shows their location and direction. It is a translucent thin flexible sheet, coated with micro-capsules containing nickel flakes suspended in oil. When magnetic lines of force are parallel to the surface of the carrier sheet, the surfaces of the flakes are reflective, and appear bright. When lines of force are perpendicular to the sheet, the flakes are edge-on, and appear significantly darker. When the film is placed on a magnet's pole, the latter case applies. Magnetic field viewing film together with a ruler can be used to measure the poles per inch of a magnet. See also * Ferrofluid * Magna Doodle References External links Magnetic devices {{electromagnetism-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maglev Train
Maglev (derived from ''magnetic levitation'') is a system of rail transport whose rolling stock is levitated by electromagnets rather than rolled on wheels, eliminating rolling resistance. Compared to conventional railways, maglev trains have higher top speeds, superior acceleration and deceleration, lower maintenance costs, improved gradient handling, and lower noise. However, they are more expensive to build, cannot use existing infrastructure, and use more energy at high speeds. Maglev trains have set several speed records. The train speed record of was set by the experimental Japanese L0 Series maglev in 2015. From 2002 until 2021, the record for the highest operational speed of a passenger train of was held by the Shanghai maglev train, which uses German Transrapid technology. The service connects Shanghai Pudong International Airport and the outskirts of central Pudong, Shanghai. At its historical top speed, it covered the distance of in just over 8minutes. Di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inductrack
Inductrack is a passive, fail-safe electrodynamic magnetic levitation system, using only unpowered loops of wire in the track and permanent magnets (arranged into Halbach arrays) on the vehicle to achieve magnetic levitation. The track can be in one of two configurations, a "ladder track" and a "laminated track". The ladder track is made of unpowered Litz wire cables, and the laminated track is made out of stacked copper or aluminium sheets. There are three designs: Inductrack I, which is optimized for high-speed operation, Inductrack II, which is more efficient at lower speeds, and Inductrack III, which is intended for heavy loads at low speed. Inductrack (or Inductrak) was invented by a team of scientists at Lawrence Livermore National Laboratory in California, headed by physicist Richard F. Post, for use in maglev trains, based on technology used to levitate flywheels. At constant velocity, power is required only to push the train forward against air and electromagnetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
