Spark, gaseous

Material Contact sparks (500 pF) Gaseous sparks (100 pF) Minimum energy Minimum capacity (pF)... 

Spark (source) ionization. Occurs when a solid sample is vaporized and partially ionized by an intermittent electric discharge. Further ionization occurs in the discharge when gaseous atoms and small molecular moieties interact with energetic electrons in the intermittent discharge. It is recommended that the word source be dropped from this term. 

The use of propane as a motor vehicle fuel has been highly developed in some countries, particularly in the USA, Holland and Italy. It is, of course, an entirely lead-free fuel. Very high efficiencies can be obtained using a gaseous fuel in spark-ignition engines since intimate mixing of the fuel and air is much more easily achieved than with a liquid fuel. This results in a much cleaner exhaust, with considerable reductions in CO and hydrocarbons. 

Nitrogen Triiodide, NI3, mw 394.77, N 3.5% a black powd, detons when dry, exposed to light, or an elec spark (Refs 8 10) Qf 35kcal/mole (Ref 7). It is formed by the interaction of free 1 or I3" on liq, gaseous, or aq ammonia (Refs 1, 8 10). N triiodide forms a series of solvates with excess ammonia NI3.NH3) bright red needles, explds when dry (Ref 2). 

Toxicity and Hazards. The odor cf ozone can be detected in concn as low as several parts per hundred million by vol (pphm). The threshold limit value (TLV) is O.lppmor 0.2mg/m3 its toxic dose level (TDL), 50% kill concn is 2ppm (Ref 6) Pure 100% liq ozone may be kept safely at 90°K (cooled by liq oxygen) for indefinite periods of time, but the smallest provocation, such as a spark or fast warming, even only up to bp (161°K), causes detonation. The evapn of liq ozone, for example, in the process of the prepn of pure gaseous ozone is, therefore, a dangerous procedure (Ref 3, p 224)... 

Ballal, D. R. and Lefebvre, A. H., A general model of spark ignition for gaseous and liquid fuel-air mixtures. 

Gaseous mixtures may explode on sparking. The mixed gases slowly react to give a mixture (NO, NOF) which, if liquefied by cooling, will explode on warming. 

A 2% beryhium mixture with copper produces a unique ahoy of bron2B that is six times stronger than copper metal. This ahoy does not give off sparks when struck with a hammer—a valuable characteristic when metals must be used in explosive gaseous envitonments. This ahoy sometimes contains smah amounts of other metals such as nickel or cobalt, which makes for excellent electrical conductivity for switching equipment, given the ahoy s simultaneous hardness and nonsparking qualities. Beryhium is also transparent to X-rays, which makes it ideal for windows for X-ray tubes. 

The simplest method for producing a spherical combustion in gases is to place a combustible (but not explosive) gaseous mixture in a thin latex, rubber or plastic balloon and ignite it in the center by means of an electric spark... 

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