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Indicated mean effective power

Other tests have been used in the past, particularly for aviation gasoline, where it was more important to discriminate accurately between fuels with ON > 100. These had the advantage of being more related to real physical phenomena. For example, the performance number [11] was based on a single standard fuel, iso-octane, and the relative indicated mean effective power (imep) (defined in terms of the cylinder pressure [3]), and so is directly related to combustion. The performance number was 100 times the ratio of the knock limited imeps of the fuel and iso-octane. Much of the API 45 project on octane number of mixtures of pure hydrocarbons (see Section 7.2.5) was reported in terms of performance number. This project of the American Petroleum Institute ran from 1938 to 1957, and has provided an invaluable source of basic data. The articles by Lovell [10] and Scott [12] review and interpret these data. Whilst this criterion and these values of CCRs [10,13] are no longer in widespread use for automotive fuels, the data available in the older literature could still be useful in testing chemical models. Because the octane number scale is based on two reference fuels, modelling the octane number of any hydro-... [Pg.669]

The elution curves, reported in Fig. 9.2, clearly indicate the effects of the two solvents. Acetone shows a peak of shorter retention time than toluene and this means a high extraction power for most of the active sites. However, after 6mL, the recovery reaches a steady state. Toluene gives a poor recovery when used first, and the average retention is higher. However, it turns out to be very useful in recovering the last traces. [Pg.213]

Experimentally, several precautions must be taken if reliable Raman data are to be obtained from solution studies. Firstly, the instrumental slit-width should be appreciably smaller than the half-width of the band to be studied. This means that slits wider than 2 cm-1 are to be avoided. Secondly, photolytic decomposition of the sample and local boiling of the solvent have also to be avoided. Careful choice of laser frequencies, use of a low incident power and, if necessary, sample spinning are indicated. The need for a relatively high solute concentration usually means that there is little choice of solvent. Particularly for coloured samples the presence of a vestigal resonance Raman effect must be tested by measurements with a variety of... [Pg.120]

The results presented here indicate that a new methanol dehydrogenation reaction path is opened when the Mo(l 12) surface is modified by a p(lx2) oxygen layer. The result of the CO adsorption experiment suggests that main electronic effect of oxygen modifier is restricted to the metal atoms directly bonded with the oxygen atoms. TTiis leads to a concept of the selective blocking of the surface atoms to create new active structures, which can provide a powerful mean to control catalytic reaction paths. [Pg.120]

The striking increase in reducing power produced by the addition of electron donors to the system indicates the existence of a strong interaction between the two types of site and means, in effect, that closely adjacent aluminum centers must be involved, at least in the cases where... [Pg.512]


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