All efficiency

On tbe basis of tbe two-film model for mass transfer, and relating all efficiencies to gas-pbase concentrations (for convenience only a similar development can be made on tbe basis of bquid concentrations), point efficiency can be expressed in terms of transfer units ... 

A review of ventilation efficiency indices is given below. Complete mixing ventilation is the comparative basis for all efficiencies, with the value 1.0. That may be useful, as complete mixing ventilation often is assumed in early design phases. 

Pd(Ph3P)4, RS02Na, CH2CI2 or THF/MeOH, 70-99% yield. These conditions were shown to be superior to the use of sodium 2-ethylhexanoate. Methallyl, crotyl, and cinnamyl ethers, the Alloc group, and allylamines are all efficiently cleaved by this method. ... 

Tray efficiency is calculated as previously demonstrated and will not be repeated, except that normally stripping tray efficiencies run lower than rectification efficiencies. For ammonia-water stripping such as this example most over-all efficiencies run 50-60%. 

The existence of a single step with a collision efficiency of 10 2 in the sequence of reactions would be insufficient to account for the absence of ionic polymerization since an over-all efficiency of about 10 5 is required by this mechanism within the first five reactions. Thus, at least two low efficiency steps are required in each series. Although... 

Very strict price control systems can give rise to higher prices at the time of introduction of a new product and the weakening of potential price reductions on expiry of a product s patent (the case for 88 per cent of products in the USA). These observations support the idea that it does not appear to be at all efficient to continue with the system of product-by-product price intervention currently in force in Spain. A regulation system that gives the company flexibility of pricing and excludes products that are subject to competition would be far more recommendable.1... 

Enantioselective carbenoid cyclopropanation can be expected to occur when either an olefin bearing a chiral substituent, or such a diazo compound or a chiral catalyst is present. Only the latter alternative has been widely applied in practice. All efficient chiral catalysts which are known at present are copper or cobalt(II) chelates, whereas palladium complexes 86) proved to be uneflective. The carbenoid reactions between alkyl diazoacetates and styrene or 1,1 -diphenylethylene (Scheme 27) are usually chosen to test the efficiency of a chiral catalyst. As will be seen in the following, the extent to which optical induction is brought about by enantioselection either at a prochiral olefin or at a prochiral carbenoid center, varies widely with the chiral catalyst used. 

The phase dependent continuum excitation has been observed by Tran et al.6 and more clearly by Story and Cooke.10 They excited the Ba 6sl9d D2 states to the region of the 6p1/2 limit and observed the fluorescence from the excited 6p1/2 state of Ba+. The resulting spectrum is shown in Fig. 21.9. Using this technique they do not detect excitation below the 6p1/2 limit at all efficiently, but are able to see the variations in the cross section above the 6p1/2 limit with remarkable clarity. 

One new way in which electrolysis could be used is by simply electrolyzing sea water to hydrogen and oxygen and then converting these to water in a fuel cell, which would supply the energy to decompose more water. Such enormous amounts of energy are used in this process that to be competitive, the over-all efficiency of the electrolysis fuel cell combination would have to be over 99.5%. It is doubtful that this could ever be attained. Other schemes of electrolysis in which sodium and chlorine are removed are subject to the same disadvantage. 

Although the methods and materials described are adequate to construct commercial irradiators today, economic forces will ultimately require the use of higher specific activities than are used today. An example will perhaps illustrate this point. Suppose one desires to build an irradiator to pasteurize strawberries. Peak loads and therefore design loads would be about 10,000 pounds per hour. About 10 kw. of radiation power at reasonable over-all efficiencies, or about 670,000 curies of 60Co, would be required. If the radiation source were made up at 2 curies per gram, one would require 4000 BNL strips in 1000 irradiation cans at a cost of 100,000 at 20 curies per gram, 400 strips in 100 irradiation cans at a cost of 10,400 ... 

The first studies on the biosynthesis of ephedrine in Ephedra distachya suggested that phenylalanine was incorporated via a C6—C2—N unit (339). When this was reinvestigated more recently, it was found that while C-3 and the aromatic ring of phenylalanine are incorporated, C-2 is not (341, 342). Specific incorporation of C-3 of phenylalanine into norpseudoephedrine in Catha edulis had also been reported (343). Further incorporation experiments showed that [carhaxy/-l4C]benzoate, [7-l4-C]benzaldehyde, and [3-l4C]cinnamic acid are all efficiently incorporated into the a carbon of ephedrine, and the participation of a C6—C, intermediate rather than a C6—C2 unit appears to be well supported (341, 342) (Scheme 4). Studies favor a biosynthetic scheme for ephedrine where C6—C, compounds such as benzoic acid or benzaldehyde react with C2—N compounds or equivalents to give ephedrine. The origin of the C2—N unit is still obscure. Methyl groups for N-methylation were previously shown to be donated from methionine or formate (538). 

In an experiment conducted in January of 2000 a total beam dose of 6.85xl0n 48Ca ions was accumulated. The chemical yield for the simultaneously produced 185Hg (Ti/2 = 49 s) was 80%. If element 112 behaved chemically like Hg and all efficiencies measured for Hg were also... 

The possible surface contaminations were carefully followed by Auger-XPS analysis. Similarly, as with the copper catalyst described earlier (Section III) the Cu/ZnO binaries were free from alkali metals, iron, chlorine, and sulfur, and contained only small amounts of carbon after the use in catalytic reactor (39). The latter result indicates that reactants, intermediates, and the product are adsorbed with moderate strength, a feature that is desirable for all efficient catalysts. 

For a well-designed impactor, a typical plot of impactor efficiency versus Vstk is shown in Fig. 7.2. It can be seen that the efficiency curve may deviate from the ideal case. In the ideal case, for all efficiencies there would be a single value of Vstk and hence a sharp size cut of the impactor. All particles larger than this size would be collected, and all smaller sizes would be passed. In actuality, this is not... 

The HHV of hydrogen is 39 kWh kg-1 and the ideal stack potential is a function of temperature and pressure. All efficiencies are referenced to the HHV of hydrogen. The minimum amount of energy that must be consumed to split water into hydrogen... 

Firing occurs only on one level, so the number of burners in relation to the number of tubes is smaller than in side-fired systems. This simplifies distribution piping for fuel gas and preheated combustion air, which is nowadays standard in all efficient plants. 

BM-DBM has a triplet energy of 59.5kcal/mol (28) and therefore a suitable quencher for BM-DBM should have a triplet energy in the order of 55 to 60 kcal/mol. Many organic molecules fulfill this requirement but not all are usable because they do not have an acceptable regulatory status which would allow their use in cosmetic preparations nor are they sufficiently photostable, per se, for this purpose. Figure 11 presents three such substances, which are all efficient quenchers for BM-DBM (29). 

To arrive at one end of this chain from the other, all the links must be in order. The probability that this will be so depends on the efficiency with which each hnk operator works if searcher, indexer, and abstractor are all 90% efficient, the over-all efficiency is 72.9% and the chance that a given piece of original information will reach the searcher is approximately 3 in 4. While it is the main object of this contribution to say a httle about the link between abstract and original, it is not always possible to avoid encroaching on the subjects of indexing and searching the main object is, nevertheless, to examine the relation between the original communication and those abbreviated forms which are indispensable to the chemist. 

Just like the ability to bind HCl, this exchange reaction is a general characteristic of all efficient PVC heat stabilizers and stabilizer systems. An essential condition of this exchange reaction, is of course, that the transferred groups - in this case a mercaptocarbonic acid ester group - have a lower tendency to be eliminated than the chlorine atom. 

Mg, MeOH, sonication, 20-40 min, 93-100% yield. The benzenesulfonyl, cyanophenylsulfonyl, 4-methoxybenzenesulfonyl and the 4-bromosulfonyl groups were all efficiently removed. The reaction is not compatible with the nosyl and Troc groups. The Troc group is converted to a dichloroethoxycar-bonyl group. ... 

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