With solvent mixtures containing alcohols (Table I), Rt values decrease with increase in the molecular weight of the alcohol added (4, 8). No movement of the ions occurred with pentanolchloroform mixtures.Butanol and 2-propanol aided in the slight movement of cobalt and iron only (Table I).Solvent mixtures 14 and 16 containing ketones gave better movement for the cations.Acetone mixtures gave a reasonable R¡ value for iron(III) only.However, the presence of 2-butanone aided in the migration of all four cations. With this solvent, cobalt and nickel gave greater Rf values than iron and copper, because the nitrates of cobalt and nickel form complexes with 2butanone (8).The presence of hydrochloric acid modified the migration tendencies of the ions in each case (Table I), and helped to give constant and reproducible R/ values. When hydrochloric acid was used, iron had an R¡ value of 1.0 in all cases. The R¡ values decreased in the following sequence when acid-containing solvents were employed: Fe > Cu > Co > Ni. (Chloroformmethanol and chloroform-acetone systems were exceptions.)An improved acidic titanium reagent for determining hydroperoxide is described. The reagent is used to determine hydrogen peroxide, ferf-butyl hydroperoxide, 1 -ethoxyethyl hydroperoxide, and the unknown peroxide resulting from the oxidation of diethyl ether on storage or on exposure to ultraviolet radiation.1 -Ethoxyethyl hydroperoxide has been postulated as a product of the oxidation of diethyl ether in air. Samples of diethyl ether, which had been oxidized in storage or by exposure to ultraviolet radiation, are analyzed by the acidic titanium method, using the improved reagent, and by an iodometric method, and the results are compared. Residues from the evaporation of oxidized ether are analyzed in an attempt to identify the oxidation products. Rscent publications (7, 10) show a renewed interest in the acidic titanium method (8, 9) for hydrogen peroxide and various organic andThe addition of phenol to an organic solvent enhanced the polarity and acidity simultaneously. Hence, Rt values for the cations increased in its presence.
permits a blank having no turbidity and therefore a very low absorbance. Furthermore, if unsatisfactory results are obtained due to accidental spillage or to an excessively high or low nitrate content, it is not necessary to repeat the entire incubation process, but merely the color development step using a suitable aliquot of supernatant solution. If many similar samples in the same range of nitrate content are to be studied, it appears that the procedure of Garner and coworkers could be employed advantageously. It employs a smaller amount of bacterial suspension to which the color reagent is directly added.The time involved in determination of nitrate by the method described varies with the number of samples to be analyzed. A standard curve must be prepared for each batch of samples, although it may not be necessary to de-termine all the points indicated, as the Beer-Lambert law is followed between 2 and 20 7 of nitrate. With a large number of samples the actual time required for media preparation, centrifugation, etc., amounts to less than 20 minutes per sample.
Sources of Information 2.0 NATURE OF AGING OR DETERIORATION 2.1 Rate of Aging 2.2 Environmental Factors Affecting Performance 2.2.1 Effect of Moisture 2.2.2 Effect of Temperature 2.2.3 Effect of Ultraviolet Radiation 2.3 Classification of Climates 2.4 Mechanical or Stress Factors 3.0 ESTIMATING THE DURABILITY OF BUILDING MATERIALS AND COMPONENTS BY MEASUREMENT OF PROPERTIES 3.1 Properties Used to Determine Durability 3.1.1 Visual Inspection and Appearance Properties.. .
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