Effect of Oxygen Balance

The heat of explosion reaches a maximum for an oxygen balance of 

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Effect of Oxygen Balance on the Explosive Properties and Design Calculation of the Formulation... 

To understand the effect of oxygen balance on the properties of explosives, the concentration of nitric acid was maintained at constant, while the oxygen balance has been changed gradually, and the results were shown in Table 7.30. 

Table 7.30 Effect of oxygen balance on explosion brisance and blasting power...

The effect of oxygen balance has been investigated experimentally with nitromethane-tetranitromethane mixtures. One observes that the heat of detonation increases with the approach of oxygen balance. The simple gamma law predictions indicate that the increasing heat of detonation should increase the C-J pressures and detonation velocities. The velocity difference between the CO— and the CO2— balanced nitromethane-TNM mixtures may be attributed entirely to the density difference. 

Their occurrence in waters causes a higher solubility of other organic low-soluble compounds. Due to their effects the oxygen balance of rivers is considerably reduced. In water treatment they cause serious difficulties with regard to their physical and chemical properties. Quite frequently they are biologically difficult-to-degrade and their biodegradability is thus an important factor which becomes a criterion for the practical use of tensides. 

The potent vasodilatory effects of PGE, have been used with success in treatment of severe forms of Raynaud s disease as well as vascular insufficiency in systemic sclerosis and other connective tissue diseases [168], PGE, and PGE2 also relax the ductus arteriosus of newborns. Infusions of PGE, (50 ng/kg/min) to newborns with certain cardiac malformations, which make the persistence of the ductus essential for the systemic or pulmonary circulation, improves the clinical condition and allows surgery to be delayed to a more suitable time (see ref. 169 for a review). The tone of the ductus arteriosus seems to be balanced between the constrictor effects of oxygen, possibly also other vasoconstrictor substances, and the dilatory effects of prostaglandins formed intramurally [170], Inhibitors of prostaglandin biosynthesis have been used to induce closure of patent ductus arteriosus of newborns, and in most cases the conventional surgical treatment could be omitted [171], For reviews on the role of prostaglandins in the vascular system see refs. 133, 165, 172 and 173. 

The influence of oxygen content was then studied by means of TPR experiments run with 2 or 10 % O2 in the presence of 500 ppm ammonia, and balance He with a GHSV of 92,000 h In this case, a minor promoting effect of oxygen concentration was seen. 

Similar experiments were carried out to determine the effect of oxygen con-cenbation on the fast SCR reaction. For these experiments, 500 ppm NO, 500 ppm NO2, and 1,000 ppm NH3 were kept constant in the inlet feed and Ar was used as a balance gas with 1,000 seem as the total flow rate. The inlet O2 concentration was varied in the range of 0-5 % for temperatures of 185,220, and 245 °C. The O2 was found to have no effect on the fast SCR reaction. Hence the apparent reaction order with respect to O2 can be considered to be zero. 

Polymerization inhibitors are key additives which prevent premature gelation of the adhesive. The foimulator must carefully balance shelf stability and the required cure on demand. Due to its high propagation rate, MMA is difficult to inhibit. Some comments on specific inhibitors follow. The most common inhibitor to be found in component monomers is 4-methoxyphenol, which is also called the methyl ether of hydroquinone. This inhibitor is effective only in the presence of oxygen. A mechanism has been proposed, and is illustrated in Scheme 13 [128]. 

Frozen mixtures of trinitromethane -2-propanol (9 1) exploded during thawing. The former (of positive oxygen balance) dissolves exothermally in the alcohol, the heat effect increasing directly with the concentration above 50% w/w. Traces of nitric acid may also have been present. 

Mixtures of stoichiometric proportions (zero oxygen balance) are a high deflagration hazard and show remarkable pressure increase effects on ignition [1], as well as lowest ignition temperatures by ARC [2],... 

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