Gas explosion technique

Table 12.19. Chemical repair rates for 02-dependent free-radical precursors of lesions in V70 cells measured using the gas explosion technique. (Prise et al. 1992)...

With pBR 322 plasmid DNA in aqueous solution containing 0.01 mol dm-3 GSH and using the gas explosion technique, the rate of repair of SSB precursors was determined at 1370 s 1 as compared to 2900 s 1 for DSB precursors (Prise et al. 1993). The OER for SSB was 3.0 and that for DSB 7.5. This is strong evidence that in this model system DSBs are formed by two close-by SSBs. 

Such studies have been extended to plasmid pBR 322 DNA by modifying the gas explosion technique and using H2S as a repair agent (Prise et al. 1998). With this assay, it was shown that the post-irradiation protection of DNA by H2S is time-dependent, having first-order rate constants of 21 s 1 for SSB and 10 s 1 for... 

Fahey RC, Prise KM, Stratford MRL, Watfa RR, Michael BD (1991) Rates for repair of pBR 322 DNA radicals by thiols as measured by the gas explosion technique evidence that counter-ion condensation and co-ion depletion are significant at physiological ionic strength. Int J Radiat Biol 59 901-917... 

A similar technique was used by Oppenheim et al. (1977) to analyze the blast waves produced by some gas explosions of a different nature ... 

The availability of large and fast computers, in combination with numerical techniques to compute transient, turbulent flow, has made it possible to simulate the process of turbulent, premixed combustion in a gas explosion in more detail. Hjertager (1982) was the first to develop a code for the computation of transient, compressible, turbulent, reactive flow. Its basic concept can be described as follows A gas explosion is a reactive fluid which expands under the influence of energy addition. Energy is supplied by combustion, which is modeled as a one-step conversion process of reactants into combustion products. The conversion (combustion)... 

If, on the other hand, blast modeling is a starting point for structural analysis, the TNT-blast model is less satisfactory because TNT blast and gas explosion blast differ substantially. Whereas a TNT charge produces a shock wave of very high amplitude and short duration, a gas explosion produces a blast wave, sometimes shockless, of lower amplitude and longer duration. In structural analysis, wave shape and positive-phase duration are important parameters these can be more effectively predicted by techniques such as the multienergy method. 

CA 37, 1603(1943) [Theoretical di s cuss ion based upon the following values density (d), gas vol per kg of expl (VD), heat of explosion (o), temp of explosion (T) and the sensitiveness to impact (S). The opinion is expressed that explosive technique cannot find anything new because all possibilities have been explored, and further advance must consist in finding new methods of use]... 

Unusual circumstances, however, may defeat any of these gas-purging techniques. It should also be remembered that batteries generate a significant amount of explosive gas during the maintenance procedure, and therefore maintenance should always be performed in a well-ventilated shop. 

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