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Topic: Electrical discharge

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	Lightning - Wikipedia, the free encyclopedia
		Lightning's abrupt electric discharge is accompanied by the emission of visible light and other forms of electromagnetic radiation.
		It has been suggested by experimental evidence that these discharges are triggered by cosmic ray strikes which ionise atoms, releasing electrons that are accelerated by the electric fields, ionising other air molecules and making the air conductive by a runaway breakdown, then starting a lightning strike.
		There is some speculation that electrical breakdown and arcing of cotton and gutta-percha wire insulation used by Tesla may have been a contributing factor, since some theories of ball lightning require the involvement of carbonaceous materials.
	en.wikipedia.org /wiki/Lightning (5238 words)

	Electric arc -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-10-08)
		The various shapes of electric arc are (additional info and facts about emergent properties) emergent properties of nonlinear patterns of (A steady flow (usually from natural causes)) current and (A field of force surrounding a charged particle) electric field.
		Low pressure electric arcs are used for lighting, e.g.
		Some more info about making electric arcs using a (Joins pieces of metal by welding them together) welder.
	www.absoluteastronomy.com /encyclopedia/e/el/electric_arc.htm (181 words)

	[No title]
		While such plasmoids are created in the laboratory by an electric discharge at the "muzzle" of a plasma gun, they are not transporters of electric charge; their plasms consists of essentially equal numbers of electrons and positive ions.
		The proportions of Lichtenberg figures are determined by such variable as the polarity of the surface with respect to the discharge, the magnitude of the impressed voltage (the potential drop across the spark gap), and the abruptness of the wave front in the flow of current.
		By means of strong electric fields associated with concentrated space charges at their outer tips, these streamers propagate outward literally at "lightning speed." At the same time, they are held to the surface by the electrostatic attraction between their tip charges and those they seek to extract from the surface.
	www.kronia.com /library/journals/escar.txt (14484 words)

	Class Definition for Class 445 - ELECTRIC LAMP OR SPACE DISCHARGE COMPONENT OR DEVICE MANUFACTURING
		An electric space discharge device is defined for the purpose of classification as including any device which is intended to have an electric current flow between two spaced parts or electrodes, at least part of the path followed by the discharge constituting a gas, vapor, or vacuum.
		for chemical preparation of a compound or element by using electrical or wave energy in a magnetic field, subclasses 164+ for chemical preparation of a compound or element by using an electrostatic field or electrical discharge and subclasses 192.1+ for coating, forming, or etching by sputtering.
		The discharge may be established between the discharge electrodes where the device being treated is a discharge device, or between any members of the device between which a discharge can be established.
	www.uspto.gov /go/classification/uspc445/defs445.htm (4990 words)

	Electrical Discharge (ESD) Phenomenon Related to Telecommunications Cabling Systems
		Static electricity is usually generated by the triboelectric effect which consists of the contact of two bodies (materials), of which at least one is insulating, and their posterior separation.
		Equivalent circuits to analyze the mechanism of charge and discharge of a human body due to the triboecletric effect are depicted in the Figure 3.
		Charge storage due to conductive coupling can occur when the electrical potential of the equipment connected to the cable in one of their ends is higher than the electrical potential of the equipment to be connected to the opposite cable end (see Figure 9).
	www.siemon.com /uk/white_papers/04-01-15_electrical_discharge.asp (2056 words)

	Electrical Discharge On The Martian Surface (Site not responding. Last check: 2007-10-08)
		Electric discharges may result from surface rover (or astronaut) motion on Mars.
		This model is analogous to a Van de Graff generator in which the moving rover is the energy source for generating static charge, the discharge point is the brush, the wind blown dust is the belt, and the Martian surface is both the charge source and the accumulator.
		With the discharge device off, relative charging of the moving rover is measured by the electrometer (perhaps using the potential first recorded after landing as a baseline).
	powerweb.grc.nasa.gov /pvsee/publications/marslight.html (2861 words)

	Different Types of Machining Processes That Use EDM
		A pulsed electrical voltage is applied between the electrode and grinding wheel in which the generated electrical discharge removes the built-up edges on the grinding wheel.
		This is a hybrid process in which material is removed by the combination action of the electrical discharge erosion and mechanical grinding for machining advanced ultra-hard materials.
		Electrical discharges help to increase the material removal rate and the mechanical grinding generates a fine surface finish.
	www.edmtt.com /articlesreports/edmprocesses.html (955 words)

	Electrical Discharge Theory: Charles Bruce (1902 - 1979)
		The role of electrical discharges in astrophysical phenomena (1975)
		Extending his idea of the existence of cosmic-scaled electrical discharges, Bruce noted that the nova eruption - popularly perceived as the explosion of a star - could also be explained using a cosmic atmospheric model.
		From the article: Electric Stars in a Gravity-Less Electrified Cosmos, by Earl Milton, appearing in SIS Reviev Vol 5.
	www.catastrophism.com /texts/bruce (961 words)

	What is EDM (Electrical Discharge Machining)?
		EDM or Electrical Discharge Machining, is especially well-suited for cutting intricate contours or delicate cavities that would be difficult to produce with a grinder, an end mill or other cutting tools.
		These electrical discharges are passed between an electrode and the piece of metal being machined.
		Electrical discharge machining is frequently used to make dies and molds.
	www.wisegeek.com /what-is-edm.htm (530 words)

	Branching electrical discharges (Site not responding. Last check: 2007-10-08)
		The main answer is that the simple principle of "electrical currents follow the path of least resistance" is guiding the path of the electrical discharge, but that the path of least resistance depends on where the electricity has already flowed, giving an interesting an nonlinear feedback situation.
		The electrical resistivity in the plasma is much less than that of ordinary air because of the presence of charged particles which are free to move.
		The electrical discharge in a plasma ball just picks a direction or directions at random when it is turned on, if it is truly symmetrical.
	van.hep.uiuc.edu /van/qa/section/Electricity_and_Magnets/Stuff_that_Sparks/20020722034338.htm (806 words)

	Electrical Discharges
		A discharge may exist in the vicinity of a sharp point, or other place with a small radius of curvature where the electric field is increased significantly from its average value.
		The arc discharge is a high-current, low-voltage discharge, in contrast with the low-current, high-voltage glow discharge.
		In arcs with thermionic cathodes, the transition is gradual as the thermionic emission increases with temperature and the discharge voltage decreases.
	www.du.edu /~jcalvert/phys/dischg.htm (13885 words)

	electrical discharge machining, edm electrodes, consumables, wire, sinker, small hole
		Electrical discharge machining (EDM) is a metal cutting process that uses electricity to "burn" away small bits of material until the desired dimensions are achieved.
		Electrical discharge machining is a very precise process that is capable of consistently holding tolerances of +/- 0.0002".
		We are ready, willing and able to assist you with all of your electrical discharge machining requirements and your EDM electrode needs.
	www.fmedm.com (221 words)

	Electrical Discharge Machining and Surface Alloying — The Process, Parameters and State of Play
		Electrical discharge machining (EDM) is a thermal process that involves melting and vaporisation of the workpiece electrode.
		The EDM process uses electrical discharges to remove material from the workpiece, with each spark producing a temperature of between 10,000-20,000°C. Consequently, the workpiece is subjected to a heat affected zone (HAZ) the top layer of which comprises recast material.
		The effect of electrical parameters such as peak current, open circuit voltage, polarity, pulse on/off times and capacitance on recast layer thickness, and workpiece microstructure, microhardness and composition, are being evaluated.
	www.azom.com /details.asp?ArticleID=2082 (1676 words)

	Electrical Discharge Machining
		"Electrical discharge machining (EDM) is a non-traditional manufacturing process based on removing material from a part by means of a series of repeated electrical discharges (created by electric pulse generators at short intervals) between a tool, called the electrode, and the part being machined in the presence of a dialectric fluid" (p.791).
		The main inconvenience with the die-sinking EDM is the electrical conductivity of the ceramic material.
		This company is an electrical discharge machining shop, that produces high accuracy components from high nickel-based alloys for aircrafts engines and land-based turbine markets.
	www.bsu.edu /web/blengle/Electrical_Disc_Machining.html (1596 words)

	Physics Demonstrations - Electricity
		Electricity is the study of the motion and effect of charges just as mechanics is the study of the motion and effect of masses.
		An electrical discharge is illustrated by connecting a high voltage power supply to a pair of conducting bars close together at the bottom and farther apart at the top, between which a discharge strikes at the bottom and rises to the top and then restrikes at the bottom.
		The electric currents flow on the outside of the cage, and the interior of the cage is all at the same electric potential.
	sprott.physics.wisc.edu /demobook/chapter4.htm (6297 words)

	EDM Machining, Wire, Small Hole, Drilling, Electrical Discharge Machining
		Electrical Discharge Machining or EDM is a highly accurate method of part production.
		With the Electrical Discharge Machining process we are capable of cutting all types of conductive materials, including exotic metals such as titanium, hastaloy, kovar, inconel, hard tool steels, carbide, etc.
		With Electrical Discharge Machining we can produce and repeat the required specifications with ease.
	www.milcowireedm.com (223 words)

	Diacell Products Ltd - Electrical Discharge Machining (EDM) (Site not responding. Last check: 2007-10-08)
		He noticed that electrical discharges had removed material from the electrodes in his experiments.
		The spark is visible evidence of the flow of electricity.
		The electrode is electrically charged by a servo-controlled generator producing the spark.
	www.diacellproducts.com /otherprod.html (418 words)

	Lightning is a transient high current electrical discharge, having path length of several kilometers (Site not responding. Last check: 2007-10-08)
		Lightning is a transient high current electrical discharge, having path length of several kilometers.
		Towards the end of a storm an electrical breakdown of the air occurs and a large amount of negative charge is dumped into the earth along narrow pathways from the cloud to the earth.
		Due to discharging action of pointed tips, an opposite charge is sprayed to the surrounding air, which neutralizes the charge on the cloud.
	www.prl.ernet.in /~bobra/EARTH/html1/chapt2.htm (1586 words)

	Modern Machine Shop: When do you need EDM? - electrical discharge machining - Emphasis : Electrical Discharge Machining
		EDM stands for electrical discharge machining but it might as well stand for Exact Difficult Machining because the applications best suited for this metal removal process are those characterized by extremely exacting tolerances and situations that would be extremely difficult or impossible to handle with any other method of machining.
		In 1943, Soviet scientists B. Lazarenko and N. Lazarenko had the idea of exploiting the destructive effect of an electrical discharge and developing a controlled process for machining materials that are conductors of electricity.
		The Lazarenkos perfected the electrical discharge process, which consisted of a succession of discharges made to take place between two conductors separated from each other by a film of non-conducting liquid, called a dielectric.
	www.findarticles.com /p/articles/mi_m3101/is_n9_v67/ai_16564321 (1523 words)

	The EDM Zone from Modern Machine Shop Online -- EDM Glossary
		An electrical impulse is used to indicate when a downward moving electrode approaches to within 0.0001 of contact with the surface of the workpiece, either to start a cut or to reposition the s electrode to resume cutting, as after dressing an electrode.
		A unit of electrical resistance equal to that of a conductor in which a current of one ampere is produced by a potential of one volt.
		A discharge that occurs as conductive particles are carried up the side of the electrode by the dielectric fluid.
	www.mmsonline.com /edm/glossary (4434 words)

	JobShop.com Manufacturing Process Definition: EDM - Wire Electrical Discharge Machining (Site not responding. Last check: 2007-10-08)
		Electrical discharge machining (EDM), sometimes referred to as spark machining, is a nontraditional method of removing metal by a series of rapidly recurring electrical discharges between an electrode (the cutting tool) and the workpiece in the presence of a dielectric field.
		EDM can cut materials regardless of their hardness or toughness, but is limited to the machining of electrically conductive workpiece materials.
		Sparks discharged from a small-diameter, tensioned wire (electrode) erode the workpiece without any contact between the tool and the part produced.
	www.jobshop.com /techinfo/electdischmachiningdef.shtml (317 words)

	D6105-04 Standard Practice for Application of Electrical Discharge Surface Treatment (Activation) of Plastics for ...
		1.1 This practice covers various electrical discharge treatments to be used to enhance the ability of polymeric substrates to be adhesively bonded.
		1.2 The types of discharge phenomena that are used for surface modification of polymers fit into the general category of nonequilibrium or non-thermal discharges in which electron temperature (mean energy) greatly exceeds the gas temperature.
		This practice defines each electrical discharge treatment technology at atmospheric pressure presented in Section and draws the necessary distinctions between them and corona discharge.
	www.astm.org /DATABASE.CART/REDLINE_PAGES/D6105.htm (330 words)

	Liquid decontamination system using electrical discharge with gas injection (US5630915)
		A liquid decontamination method and apparatus uses a series of pulsed electrical arcs across electrodes placed within a liquid stream which passes through a decontamination module.
		Sufficient energy is delivered by a pulse generator to the electrodes whereby lethal ultraviolet radiation and mechanical shock waves are created by the arcs within the decontamination module.
		pulse generator means for generating a series of electric arcs between said anode electrode member and said cathode electrode members.
	www.delphion.com /details?pn=US05630915__ (473 words)

	Electrical Discharge Machining - Top Electrical Discharge Machining Resources, Reviews and Information (Site not responding. Last check: 2007-10-08)
		Electrical discharge machining is a method of working extremely hard materials or materials that are...
		Electrical discharge machining (EDM) is a metal cutting...
		EDM - Electrical discharge machining is a machining process used mainly for producing dies, molds...
	www.machiningadvisor.com /listings57.html (572 words)

	Electrical Discharge Milling (Site not responding. Last check: 2007-10-08)
		Electrical Discharge Milling Electric sparks are the cutting edges of the new tools to machine hard metals.
		In electrical discharge milling, or spark machining as it is sometimes called, metal is removed by controlled electrical discharges across a dielectric gap.
		This process process is used for regular shop jobs such as drilling, reaming, broaching, die sinking and grinding and other work in hard metal alloys which are impractical to carry out with conventional equipment.
	talkaboutabook.com /group/misc.books.technical/messages/19674.html (139 words)

	Electrical Discharge Machining, Precision EDM Machining, California
		Wire Cut Company an Electrical Discharge Machining Job Shop has earned a reputation for quickly and economically producing parts that defy traditional EDM job shop manufacturing techniques.
		Electrical Discharge Machining EDM machining & engineering assistance with complete CAD/CAM support is available at every level of your edm machined component or part development process to ensure the creation of a cost effective design.
		As your precision Electrical Discharge Machining service company in California your EDM design moves forward toward completion, our production personnel become involved to make sure they have a thorough understanding of your electrical discharge machining EDM service, requirements, and specifications.
	www.wirecut-co.com (143 words)

	Research Abstract: 1981-04-15 Diesel Particulates Destruction By Electrical Discharge Technique
		When the engine exhaust carrying the particulates flows through the electrodes, the particulates trigger spark discharges in the latter, which in turn destroy the particulate.
		(3) The electrical power required to operate such a destruction device is small and is affordable by light duty vehicles.
		For a moderate particulate emission or destruction rate, the electrical power required can be made to be 50 watts or less.
	www.arb.ca.gov /research/abstracts/a0-047-32.htm (309 words)

	Electrical Discharge Machining (LAI)
		In electrical discharge machining (EDM) the workpiece surface is machined by electrical discharges occurring in the gap between two electrodes -- the tool and the workpiece.
		Some parameters can be controlled during the process (gap, flow), some require process interruption (duration of discharges,...), and some of them are inherent to the particular machining task.
		For a standard set of workpiece types there exist predefined sets of values for the process parameters which guarantee a certain degree of generated surface quality.
	www-ai.ijs.si /~ilpnet2/apps/edm.html (913 words)

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