electric arc

A sunspot is a region on the Sun's surface (photosphere) that is marked by a lower temperature than its surroundings, and intense magnetic activity. Although they are blindingly bright, at temperatures of roughly 5000 K, the contrast with the surrounding material at some 6000 K leaves them clearly visible as dark spots. If they were isolated from the surrounding photosphere they would be brighter than an electric arc. We are currently near a minimum (predicted for 2007) in the sunspot cycle [1]. Sunspot ...

Including:

• Sunspot - Sunspot variation
• Sunspot - History
• Sunspot - Significant events
• Sunspot - Physics
• Sunspot - Application

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Any explosive material has the following characteristics: It is chemically or otherwise energetically unstable. The initiation produces a sudden expansion of the material accompanied by the production of heat and large changes in pressure (and typically also a flash or loud noise) which is called the explosion. Explosive material - Chemical explosives. Explosives are classified as low or high explosives according to their rates of decomposition. Low explosives burn rapidly (or d ...

Including:

• Explosive material - Chemical explosives
• Explosive material - Explosive compatibility groupings
• Explosive material - Low Explosives
• Explosive material - High Explosives
• Explosive material - Composition of the material
• Explosive material - Chemical explosive reaction
• Explosive material - Formation of gases
• Explosive material - Evolution of heat
• Explosive material - Rapidity of reaction
• Explosive material - Initiation of reaction
• Explosive material - Sensitiser
• Explosive material - Military explosives
• Explosive material - Availability and cost
• Explosive material - Sensitivity
• Explosive material - Stability
• Explosive material - Power
• Explosive material - Brisance
• Explosive material - Density
• Explosive material - Volatility
• Explosive material - Hygroscopicity
• Explosive material - Toxicity
• Explosive material - Measurement of chemical explosive reaction
• Explosive material - Oxygen balance OB%
• Explosive material - Heat of explosion
• Explosive material - Balancing chemical explosion equations
• Explosive material - Volume of products of explosion
• Explosive material - Explosive strength
• Explosive material - Example of thermochemical calculations

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An arc lamp is a device that produces light by the sparking (or arcing, from voltaic arc or electric arc) of a high current between two carbon rod electrodes. The rods are touched and then slowly drawn apart; as the rods separate the current is "struck" and arcs across the gap in a bright, ionized path. The arc produces a temperature of several thousand degrees, and the tips of the carbon rods are heated to incandescence, creating light. The rods are slowly vaporized during the process and need to be regularly adjusted to maintain the ...

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Charge carrier denotes in physics a free (mobile, unbound) particle carrying an electric charge. Examples are electrons and ions. In semiconductor physics, the travelling vacancies in the valance-band electron population (holes) are treated as charge carriers. In ionic solutions, the charge carriers are the dissolved cations and anions. Similarly, cations and anions of the dissociated liquid serve as charge carriers in liquids and melted ionic solids (see eg. the Hall-Herou ...

Including:

• Charge carrier - Majority and minority carriers in semiconductors

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Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, but sometimes pressure is used in conjunction with heat, or by itself, to produce the weld. This is in contrast with soldering and brazing, which involve melting a lower-melting-point material between the workpieces to form a bond ...

Including:

• Welding - History
• Welding - Welding processes
• Welding - Arc welding
• Welding - Gas welding
• Welding - Resistance welding
• Welding - Energy beam welding
• Welding - Solid-state welding
• Welding - Geometry
• Welding - Quality
• Welding - Heat-affected zone
• Welding - Distortion and cracking
• Welding - Weldability
• Welding - Unusual conditions
• Welding - Safety issues
• Welding - Costs and trends
• Welding - Notes

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Arc welding refers to a group of welding processes that use a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding region is sometimes protected by some type of inert or semi-inert gas, known as a shielding gas, and/or filler material. Arc welding - Development. While examples of welding go back to the Bronze Age a ...

Including:

• Arc welding - Development
• Arc welding - Power supplies
• Arc welding - Consumable electrode methods
• Arc welding - Non-consumable electrode methods
• Arc welding - Corrosion issues
• Arc welding - Safety issues

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The term Arc is derived from the Latin word "arcus" meaning "bow". Arc - Meanings. Arc - Mathematics and geometry. An arc is a continuous portion of a circle; part of a circle's circumference (also called a circle segment). Minute of arc or second of arc, measurements of angle. Directed edge (graph theory), a one-way link between two nodes in a graph. Arc - Science and computing. ComputingIncluding:

• Arc - Meanings
• Arc - Mathematics and geometry
• Arc - Science and computing
• Arc - Entertainment
• Arc - Geography
• Arc - Aviation
• Arc - Other

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The word spark has several meanings: In electricity, "spark" usually refers to a momentary electrostatic discharge across a spark gap. It can also refer to a continuous electric arc or a corona discharge. A spark may be a small airborne ember or particle of glowing, hot metal from a fire, grinding machine, the heat from an electric spark as above, or the like. SPARK programming language Small Portable Adjustable Real-time Kernel, by Real Time Microsystems ...

Including:

• Spark - Common misspellings

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Welding - Arc welding. Arc welding processes use a welding power supply to create and maintain an electric arc between an electrode and the base material to melt metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding region is sometimes protected by some type of inert or semi-inert gas, known as a shielding gas, and fille ...

See also:

Welding, Welding - History, Welding - Welding processes, Welding - Arc welding, Welding - Gas welding, Welding - Resistance welding, Welding - Energy beam welding, Welding - Solid-state welding, Welding - Geometry, Welding - Quality, Welding - Heat-affected zone, Welding - Distortion and cracking, Welding - Weldability, Welding - Unusual conditions, Welding - Safety issues, Welding - Costs and trends, Welding - Notes

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A transformer usually has: two or more insulated windings, to carry current a core, in which the mutual magnetic field couples the windings. In transformers designed to operate at low frequencies, the windings are usually formed around an iron or steel core. This helps to confine the magnetic field within the transformer and increase its efficiency, although the presence of the core causes energy losses. Transformers made to operate at high frequencies may use other l ...

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Transformer, Transformer - Introduction, Transformer - Basic principles, Transformer - Flux coupling, Transformer - Electrical laws, Transformer - Invention, Transformer - Practical considerations, Transformer - Classification, Transformer - Losses, Transformer - High frequency operation, Transformer - Construction, Transformer - Cores, Transformer - Windings, Transformer - Insulation, Transformer - Shielding, Transformer - Coolant, Transformer - Terminals, Transformer - Transformer designs, Transformer - Autotransformers, Transformer - Polyphase transformers, Transformer - Resonant transformers, Transformer - Instrument transformers, Transformer - Pulse transformers, Transformer - RF transformers, Transformer - Uses of transformers

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While examples of welding go back to the Bronze Age and the Iron Age, arc welding did not come into practice until much later. In 1800, Sir Humphrey Davy discovered the electric arc, initiating the development of arc welding which continued with the inventions of metal electrodes by a Russian (N.G. Slavianoff) and an American (C.L. Coffin) in the late 1800s even as carbon arc welding, which used a carbon electrode, gained popularity. Around 1900, A. P. Strohmenger released in Britain a coated metal electrode which gave a more stable arc. In 1919, alternating current welding was invented by C.J. Holslag but ...

See also:

Arc welding, Arc welding - Development, Arc welding - Power supplies, Arc welding - Consumable electrode methods, Arc welding - Non-consumable electrode methods, Arc welding - Corrosion issues, Arc welding - Safety issues

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The term plasma is generally reserved for a system of charged particles large enough to behave as one. Even a partially ionized gas in which as little as 1% of the particles are ionized can have the characteristics of a plasma (i.e. respond to magnetic fields and be highly electrically conductive). In technical terms, the typical characteristics of a plasma are: Debye screening lengths that are short compared to the physical size of the plasma. Large number of particles within a sphere with a radius of the Debye length. Mean time between collisions usually is long when com ...

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Plasma physics, Plasma physics - Common plasmas, Plasma physics - Characteristics, Plasma physics - Plasma scaling, Plasma physics - Temperatures, Plasma physics - Densities, Plasma physics - Potentials, Plasma physics - In contrast to the gas phase, Plasma physics - Complex plasma phenomena, Plasma physics - Ultracold plasmas, Plasma physics - Mathematical descriptions, Plasma physics - Fluid, Plasma physics - Kinetic, Plasma physics - Particle-in-cell, Plasma physics - Fundamental plasma parameters, Plasma physics - Frequencies, Plasma physics - Lengths, Plasma physics - Velocities, Plasma physics - Dimensionless, Plasma physics - Miscellaneous, Plasma physics - Fields of active research

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A lathe is a machine tool which spins a block of material so that when abrasive, cutting, or deformation tools are applied to the workpiece, it can be shaped to produce an object which has rotational symmetry about an axis of rotation. Examples of objects that can be produced on a lathe include candlestick holders, table legs, bowls, baseball bats, crankshafts or camshafts. The material may be held in place by a chuck or worked between one or two centers of which at least one can be moved horizontally to accommodate vary ...

See also:

Metalworking, Metalworking - Milling, Metalworking - Turning, Metalworking - Marking out, Metalworking - Drilling and threading, Metalworking - Welding, Metalworking - Hand fabrication, Metalworking - Grinding

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Principal methane sources are Outgassing from earth's mantle through mud volcanoes. Mud volcanoes are often associated with petroleum deposits and tectonic subduction zones and orogenic belts. Hydrocarbon gases often are erupted. According to geologist Nikolai Kudryavtsev, the eruptions of mud volcanoes have liberated such large quantities of methane that even the most prolific gas field underneath should have been exhausted long ago. Also the quantities of mud deposited in some cases would have required eruptions of much ...

See also:

Methane, Methane - Sources of methane, Methane - Reactions of methane, Methane - Extraterrestrial Methane, Methane - Methane on Earth, Methane - Uses, Methane - Units of measure, Methane - Methane in heraldry

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Tesla coil - Transmission. A large Tesla coil of more modern design can operate at very high peak power levels, up to many megawatts (a million watts; hundreds of thousands of horsepower). It should therefore be adjusted and operated carefully, not only for efficiency and economy, but also for safety. If, due to improper tuning, the maximum voltage point occurs below the terminal, along the secondary coil, a discharge (spark), or possibly a ball of plasma, may break out and damage or destroy the coil wir ...

See also:

Tesla coil, Tesla coil - History, Tesla coil - Early coils, Tesla coil - Disruptive Tesla coils, Tesla coil - Later coils, Tesla coil - Description, Tesla coil - Utilization and production, Tesla coil - Transmission, Tesla coil - Safety and precautions, Tesla coil - Air discharges, Tesla coil - Reception, Tesla coil - The skin effect myth, Tesla coil - Instances and devices, Tesla coil - Popularity, Tesla coil - Related Tesla patents, Tesla coil - Further reading and other references

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Spark gaps are frequently used to prevent voltage surges from damaging equipment. Spark gaps are used in high-voltage switches, for example, in power plants and electrical substations. Such switches are constructed with a large, remote-operated switching blade with a hinge as one contact and two leaf springs holding the other end as second contact. If the blade is opened, a spark may keep the connection between blade and spring conducting. (The spark ionizes the air, which becomes conductive, allowing an arc to form, which sustains io ...

See also:

Spark gap, Spark gap - Spark gaps as ignition devices, Spark gap - Spark gaps as radio transmitters, Spark gap - Spark gaps as protective devices, Spark gap - Spark gaps as power-switching devices, Spark gap - Spark gaps as entertainment, Spark gap - Spark gaps in nature

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Depending upon the design of the torch (e.g., orifice diameter), electrode design, gas type and velocities, and the current levels, several variations of the plasma process are achievable, including: Plasma Arc Welding (PAW) Plasma Arc Cutting (PAC) Plasma Arc Gouging Plasma Arc Surfacing Plasma Arc Spraying Plasma arc welding - Plasma Arc Cutting PAC. When used for cutting, the plasma gas flow is increased so that the deeply penetrating plasma jet cu ...

See also:

Plasma arc welding, Plasma arc welding - Other Plasma Arc Processes, Plasma arc welding - Plasma Arc Cutting PAC, Plasma arc welding - Suggested Additional Reading

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Founded as Saint Ignatius Academy by the Italian Jesuits Anthony Maraschi, Joseph Bixio and Michael Accolti in 1855, USF began life in a wood frame building along Market Street in what later became downtown San Francisco. A charter from the state of California in 1859 changed the school's name to Saint Ignatius College and granted it the power to confer degrees. The original curriculum included Greek, Spanish, Latin, English, French, Italian, algebra, arit ...

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University of San Francisco, University of San Francisco - History, University of San Francisco - Structure and degrees, University of San Francisco - The campus, University of San Francisco - Athletics, University of San Francisco - Basketball, University of San Francisco - Men's Soccer, University of San Francisco - Others, University of San Francisco - Miscellaneous, University of San Francisco - Notable alumni

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Shielded metal arc welding equipment typically consists of a constant current welding power supply and an electrode, with an electrode holder, a work clamp, and welding cables (also known as welding leads) connecting the two. Shielded metal arc welding - Power supply. The power supply used in SMAW has constant current output, ensuring that the current (and thus the heat) remains relatively constant, even if the arc distance and voltage change. This is important because most applications of SMAW are manual, ...

See also:

Shielded metal arc welding, Shielded metal arc welding - Development, Shielded metal arc welding - Operation, Shielded metal arc welding - Quality, Shielded metal arc welding - Safety, Shielded metal arc welding - Application, Shielded metal arc welding - Equipment, Shielded metal arc welding - Power supply, Shielded metal arc welding - Electrode, Shielded metal arc welding - Process variations, Shielded metal arc welding - Notes

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To perform gas metal arc welding, the basic necessary equipment is a welding gun, a wire feed unit, a welding power supply, an electrode wire, and a shielding gas supply. Gas metal arc welding - Welding gun and wire feed unit. The typical GMAW welding gun has a number of key parts—a control switch, a contact tip, a power cable, a gas nozzle, and electrode conduit and liner, and a gas hose. The control switch, or trigger, when pressed by the operator, initiates the wire feed, electric power, and the shiel ...

See also:

Gas metal arc welding, Gas metal arc welding - Development, Gas metal arc welding - Equipment, Gas metal arc welding - Welding gun and wire feed unit, Gas metal arc welding - Power supply, Gas metal arc welding - Electrode, Gas metal arc welding - Shielding gas, Gas metal arc welding - Operation, Gas metal arc welding - Technique, Gas metal arc welding - Quality, Gas metal arc welding - Safety, Gas metal arc welding - Metal transfer modes, Gas metal arc welding - Globular, Gas metal arc welding - Short-circuiting, Gas metal arc welding - Spray, Gas metal arc welding - Pulsed-spray, Gas metal arc welding - Notes

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