Performance number

There is therefore a need to consider how to link scientific and business performance numbers in a way that is both transparent and soundly based. There has been much written but little agreed on about this important point. 

The acid dilution factor x9 could be expressed as a linear function of the F-4 performance number xlQ... 

The referenced Siemens Westinghouse pnblication presented the cycle concept and overall performance valnes. Neither specific stream information nor assnmptions were presented. The stream data and assumptions presented here were developed by Parsons. The stream data were developed using an ASPEN simulation which yielded performance numbers in general agreement with the publication. 

This value is primarily used to rate the antiknock values of aviation gasolines with octane numbers over 100. It is defined as the maximum knock-free power output obtained from fuel expressed as a percentage of the power obtainable from isooctane. The relationship between octane number and performance number is listed as follows ... 

Knock value, min. Rich rating performance number — 130 130... 

Wiese Formula An empirical formula developed by General Motors Research for expressing motor fuel antiknock values above 100. This value is obtained by measuring the number of milliliters of tetraethyl lead added per gallon to achieve the same knocking tendency as the fuel being tested. The determined value is then expressed as a performance number. 

TABLE 4.4 The Final Converter Performance Numbers Using PQ2620 Transformers... 

Table 4.4. shows that the final converter performance numbers using PQ2620 transformers are in excellent agreement with SPICE simulation data produced by PSpice. 

Figure 11. Performance Number Equivalents for Octane Numbers and Tetraethyllead in Iso-octane...

Using this performance number scale as the measure of quality, an appraisal of the average regular and premium grades of motor gasoline of 1950 is shown in Figure 12. It... 

The cost of obtaining incremental performance numbers by refining processes is difficult to determine because of variations in refinery practices and equipment, in product demand from refinery to refinery, and in crude sources. The cost of obtaining a similar incremental increase in performance number by use of tetraethyllead can be accurately obtained. 

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-... 

Both types of anti-knock are more effective in paraffinic fuels then in olefinic or aromatic fuels, and can even promote knock when added to some alcohols. In Fig. 7.9 the response of some pure hydrocarbons to the addition of 3ml/US gal of tetra-ethyl lead is shown, in terms of Performance Number. Almost all the alkanes lie on a steeper line than the alkenes. The exceptions are low octane number alkenes, which are largely straight alkane chains, and a few highly-branched alkanes (which also have high sensitivity, see Section 7.2.3). Notwithstanding the subtleties of lead additives, a broad explanation in chemical kinetic terms is that the antiknock acts to increase radical termination rates and, consequently, has proportionately less effect in those fuels where the termination rates are already high. 

Fig. 7.9. Effect on octane quality of adding 3 ml/US gal tetra-ethyl lead to pure alkane and alkene fuels. The Performance Number is a practical measure of the propensity of a fuel to knock and related to the research octane number, RON, by the empirical formula PN = 2800/(128-RON). Except for a few highly branched species, the TEL increases the the performance number of alkanes by a constant factor of 1.5. It is less effective in alkene...

Another problem is that switching of the SHG signal is possible only for a limited number of cycles the higher SHG value reached after UV irradiation decreases with the performed number of cycles. This decrease is interpreted as an effect of disorientation. Indeed, in the absence of a poling field, the chromophores have no reason to recover exactly the same orientation after one isomerization cycle. In the worst cases, the poled order is completely lost after one switching attempt. Usually, this type of disorientation occurs faster in side-chain polymers than in doped ones. ... 

P3-25 Load the Interactive Conpiter Module (ICM) fiom the CD-ROM Run the module and then record your performance number for the module which indicates your mastering of flhemateiiaL Your professor has the to S your performance number,... 

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