Glow and ignition

Early work on phosphorus oxidation was concerned with the spectrum of the glow and the ignition. Later, information was gathered on the glow and ignition limits. The more recent emphasis has been on the determination of a reaction mechanism, However, to date the mechanism is not yet established unambiguously, and no rate coefficients have been measured. 

Emeleus and Purcell examined the emission of P2O5 excited by the absorption of radiation. They found no ultraviolet emission and confirmed the earlier results of Ebert and Hoffmann that the visible emission was continuous with maximum intensity in the green. On the other hand, an electrical discharge through P2O5 vapor gave a complex band system, in which were included the bands of the spectrum of glowing phosphorus. 

This emission undoubtedly is also present in phosphorus combustion, as Cordes and Witschel have shown that calculated frequencies for PO2 correspond to the weak band spacing in the phosphorus glow. 

Bowen and Pells measured the ratio of light emission to chemical oxidation and concluded that at least one in 2000 molecules of P4 oxidized emits a quantum of visible light. 

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A very violent detonation occurred when a mixture of chromium trioxide and acetic acid was heated (this mixture is used as an oxidant). The investigation showed that this accident was caused by liquid acid being in contact with oxide particles. These particles glowed and ignited the air/acid vapour mixture, which caused the apparatus to detonate. 

The effect of added mixed hydrocarbons at any temperature was to inhibit both the glow and ignition. Thus the upper limit was lowered and the lower limit raised. Presumably the hydrocarbons act as scavengers of the oxygen atoms and thus enhance the termination. 

Heat released by the reaction causes unreacted sodium to give off a characteristic yellow glow and ignites the hydrogen g... 

Stock and working solutions were stored at a temperature of — 20°C. The ul-trapure water was obtained by purifying demineralized water in a Milli-Q-system. All organic solvents were HPLC-grade. A 30% hydrochloric acid solution was ttsed and the qrrality of the formic acid was 98%. Sea sand was obtained from Mallinck-rodt Baker, Deventer, The Netherlands and had been glowed and ignited by the manufactrrrer. 

Scatter in these data indicate accuracy, but they suggest that the earliest ignition time would be piloted, followed by glowing and then autoignition. This still may not preclude the effect of smoldering on piloted ignition at very low heat fluxes, as occurs with autoignition at 40 kW/m2. 

Boonmee, N. and Quintiere, J.G., Glowing and flaming auto-ignition of wood, in 29th Symposium (International) on Combustion, The Combustion Institute, Pittsburg, Pennsylvania, 2002, pp. 289-96. 

FUSEE An article resembling a safety match but which has additional pyrotechnic composition that glows after ignition and is essentially wind-proof and weather-proof. Used for lighting fuses. 

One cubic centimeter of absolute ethyl alcohol is placed in the cup from a suitable pipett or other means, and ignited with the test specimen in place with a suitable practical flame, which is removed as soon as the alcohol is lighted. One minute after the.fuel has been exhausted, any flame and glow on the specimen are extinguished and reported and the area of char is measured. 

To overcome the lack of mobility the slow match was developed. The match consisted of a piece of cord which had been soaked in a strong solution of potassium nitrate and then dried. When placed in the touch hole and lit, the match would smolder with a glowing end at the rate of about an inch a minute until it reached and ignited the propellant.12 Speed of ignition and dependence on weather conditions were serious disadvantages. 

ASTM D 6194, Standard Test Method for Glow Wire Ignition of Materials, Annual Book ASTM Standards, American Society for Testing and Materials, West Conshohocken, PA. 

As explained in Section 2.5 and Table 2.5, the relevant standards ask for a certain tightness of the enclosure against the ingress of dust and a surface temperature ensuring a certain margin of safety related to the glow temperature and ignition temperature of the combustible dust referred to. 

The metal or alloy does not dissolve completely. The solution (A) is examined as in case 1. If the residue is black, it may be either carbon or gold and/or platinum. Test for carbon by igniting on a crucible lid carbon glows and burns. Gold and platinum dissolve in aqua regia (compare Sections VII.7 and VII.8). 

Fig. 5.32. The p-T regions for steady dark reaction, steady glow, oscillatory glow and oscillatory ignition, and the influence of added H2 for the CO + O2 reaction in a flow reactor with = 8 S , (a) no added H2 (b) 150 ppm added H2 (c) 1500 ppm added H2 (d) 7500 ppm added H2 (e) 10% H2 in final mixture. (Reprinted with permission from reference [64], Royal Society of London.)...

Diethylmagnesinm catches fire spontaneonsly in air. It is snsceptible to glow and can catch fire in other gases, as well, that contain oxygen atoms in the molecnles, snch as N2O and even 02. It explodes with water. The ether soln-tion of the componnd is also snsceptible to ignition, upon contact with water (Bretherick... 

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