Internal sparks

This point is of importance in airships, as, providing the purity of the hydrogen in the envelope is above 80 per cent by volume, an internal spark in the envelope will not cause an explosion, but if the quantity of hydrogen by volume falls below this amount there is a risk of explosion hence the procedure of deflating airships when the purity has dropped to 80 per cent hydrogen by volume. 

Some manufacturers use internal metal shields to protect computer housings from internal sparks and heat, and can therefore use non-flame retarded plastics. 

When corona occurs, current starts to flow in the secondary circuit and some dust particles are precipitated. As potential is increased, current flow and electric field strength increase until, with increasing potential, a spark jumps the gap between the discharge wire and the collecting surface. If this "sparkover" is permitted to occur excessively, destmction of the precipitator s internal parts can result. Precipitator efficiency increases with increase in potential and current flow the maximum efficiency is achieved at a potential just short of heavy sparking. 

Inductively coupled argon plasma (icp) and direct current argon plasma (dcp) atomic emission spectrometry are solution techniques that have been appHed to copper-beryUium, nickel—beryUium, and aluminum—beryUium aUoys, beryUium compounds, and process solutions. The internal reference method, essential in spark source emission spectrometry, is also useful in minimizing drift in plasma emission spectrometry (17). Electrothermal (graphite... 

There are several important Hquid fuels, ranging from volatile fuels for internal combustion engines to heavy hydrocarbon fractions, sold commercially as fuel oils. The technology for the combustion of Hquid fuels for spark-ignition and compression-ignition internal combustion engines is not described here. 

Loose or mis- Preventative maintenance and operator prestart placed internal checklist hardware causes heat/sparks during plowing out. CCPS G-22... 

Magnesium anodes must not be used in tanks. Aluminum anodes may be installed in all tanks according to the agreements of the International Association of Classification Societies, which are included in the individual regulations [5,6], but in tanks (b) in the event of the anode falling off, the kinetic energy must not exceed 275 J, i.e., a 10 kg anode must not be fixed more than 2.8 m above the bottom of the tank. There are no restrictions on the use of zinc anodes. The restrictions on the use of aluminum anodes are due to the possible danger of sparks if the anode falls off. 

Calibration curves must be made using a series of standards to relate emission intensities to the concentration of each element of interest. Because ICP-OES is relatively insensitive to matrix effects, pure solutions containing the element of interest often are used for calibration. For thin films the amount of sample ablated by spark discharges or laser sources is often a strong function of the sample s composition. Therefore, either standards with a composition similar to the sample s must be used or an internal standard (a known concentration of one element) is needed. 

Elame arresters for chemical process equipment and flammable liquid containers have been available for over 120 years. A US patent was issued as early as 1878 for a spark-arrester (Allonas 1878), while another spark-arrester was patented in 1880 (Stewart 1880). Numerous US patents have been issued for various designs of flame arresters, with one as recent as 1995 (Ronssakis and Brooker 1995). In Germany, patents were issued in 1929 and 1939 for flame arresters that contained shock absorber internals upstream of the flame arrester elements. This innovation made them suitable as detonation arresters (Wanben 1999). 

The deposits formed in internal combustion engines by high-octane petrols may be classed as ashes they consist of mixtures of lead oxides, bromides and sulphates derived from the anti-knock additives and, of course, exert their main corrosive effect on the parts operating at the highest temperature the exhaust valves and the sparking-plug electrodes. 

FIGURE 13.20 This flame front was caught during the fast combustion— almost a miniature explosion—that occurs inside an internal combustion engine every time a spark plug ignites the mixture of fuel and air. 

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