Mean uses per compound

The mean uses per compound in Table V is 1.7. The mean uses per compound can be counted tor each ot the uses, it was shown (9) that mean uses per compound is distributed statistically and the outliers on each side could be identified. The ones with low mean uses per compound were highly specific uses such as antimicrobial, antineoplastics, antihistaminics, estrogenics, etc. The ones with high mean uses were the ones which were present in dominant use pairs or clusters such as diuretics, vasodilator, CNS depressant, etc., or which had old imprecise use descriptors such as sudorific, diaphoretic, dermatoses, etc. 

Specificity. Several attempts were made to develop a non-parametric statistical description of the specificity question, based on techniques from numerical linguistics. It was hoped that sets of very specific or very nonspecific uses would naturally emerge in the analysis. But it was found that a simple parametric statistic did far better than nonparametric ones the mean uses per compound for each use. The mean uses... 

Figure 3. Distribution of mean uses per compound. Outliers are identified in Table V. Population mean, ------- 2 a deviation, 3 a deviation,-----.

Activation of H2O2 may be achieved under several different conditions nucleophilic activation, electrophilic activation, radical activation, activation by means of organic compounds which give different and more active per-oxidic species, activation by use of transition metal derivatives. Emphasis will be given to this last modality, which occurs via formation of metal-oxo or metal-peroxo complexes, which are the actual catalytic species responsible for the oxidation of organic substrates. 

Examples of chemical blowing agents are azo compounds, N-nitroso-compounds, and sulphonyl hydrazides, which yield 10()-3()() cm of nitrogen per gram of compound at temperatures of 90-2 7 5°C. Azodicarbonamide is widely used, having a decomposition temperature of 230-235°C, which can be reduced to 155-200°C by means of metal compounds such as lead and zinc stabilizers. It can thus match the temperatures at which the melt viscosity of many polymers is suitable for foaming, and is used (typically) in calendered PVC and PVC plastisols and in structural foam forms of polyethylene, polypropylene, PVC, polystyrene, and ABS. 

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