摘要:

AbstractA detailed examination has been made of the ulmic acids obtained by the anodic oxidation of the Meltonfield vitrain. The ulmic acids were fractionated into acetone‐soluble and acetone‐insoluble portions. The former fraction yielded an appreciable extract when treated with ether, although none was obtained when the original acids were extracted directly with ether. Although this ether‐soluble portion was resin‐like in appearance, the products obtained on destructive distillation were not sufficiently different from those obtained by similar treatment of ulmic acids, to classify it as being resinic. Molecular weights, equivalent weights and ultimate analyses of the various fractions bear a close resemblance to those of ulmic acid fractions obtained from coal by other oxidizing agents. A limiting composition for the ulmic acids appeared to be reached after prolonged tr

ISSN:0368-4075    

DOI:10.1002/jctb.5000670701

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractA number of miscellaneous experiments has been undertaken using the apparatus described in previous papers. An anthracite has been oxidized at the copper cathode and, as is to be expected, much smaller yields were obtained than from a similar treatment of a vitrain. The amount of water‐soluble acids was much less than that of the ulmic acids. An attempt to oxidize two durains, in order to isolate the plant remains, proved unsuccessful, for it was found that unless the coal was ground to pass a 240 B.S. sieve; little oxidation took place. The durains could not be. ground to this fineness since the original structure of the plant entities would be destroyed.Fractions obtained from coal by treatment with pyridine followed with chloroform, i.e., the β‐fraction and the γ‐fraction have been oxidized at the copper cathode and yield ulmic acids. The molecular weights were similar to those of ulmic acids obtained from the direct oxidation of coal. This accords with the work of Biggs who similarly examined the fractions obtained by pressure‐benzene extraction, followed by nitric acid oxidation, and supports his theory that the difference between the various fractions is one of molecular size rather than of chemical type.Reduction of the vitrain at a copper cathode appeared to effect little change. However, reduction of the ulmic acid appears to increase its adsorptive power for electrolytes. It was not found possible to free the reduced ulmic acids from electrolyte by prolonged washing and they were no longer soluble in furfural and other solvents. It was thus not found possible to obtain a pure sample of the reduced ulmic acids.A general summary of the work is given and suggestions made for fur

ISSN:0368-4075    

DOI:10.1002/jctb.5000670702

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractA process has been developed to enable Spectrographic analyses to be carried out in approximately ten minutes. This speed has been attained chiefly through attention to the methods of processing the photographic plates, “which are developed and fixed in ultra rapid reagents, washed for a minimum time and dried in an oven designed for the purpose. A single analysis can be carried out in 8 1/2 minutes with an error of ± 4% using fast photographic plates or in 9 1/2 minutes with an error of ± 3% using a slower plate. An addition of about 2 minutes to either of these times permits duplicate determinations to be made with a reduction of some 30% in the analytical error. It is suggested that in routine practice duplicate determinations should be carried out wherever time permits; this precaution is particularly desirable, apart from the increase in accuracy it allows, in applications where the method is to be used for controlling the composition of molten metal prior to casting. In this case any delay in the release of the analytical result, due to a blemish on the photographic emulsion or a scratched or dirty plate due to faulty manipulation during processing, may cause serious inconvenience in the casting shop or refin

ISSN:0368-4075    

DOI:10.1002/jctb.5000670703

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractA criterion is derived empirically from tabular solutions of the Diffusion Law to show whether the rate of change of the moisture content of a wrapped hygroscopic commodity, stored in an atmosphere with which it is not in equilibrium, is controlled predominantly by the resistance of the superficial wrapper to the passage of water or by the bulk impedance of the commodity. Measurements on some typical small packets indicate that a surface resistance is the predominant factor, even with unwrapped commodities.

ISSN:0368-4075    

DOI:10.1002/jctb.5000670704

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractQuantitative data for the rate of decomposition of β‐indolyl acetic acid added to soils have been obtained and the rate of decomposition shown to be very rapid. Normal dressings of organic manures such as dung and dried blood have been found to increase the auxin content of soils towards the maximum value in what has been previously described as the “normal auxin range” of soils. This increase may be maintained for a period of some months, and in the dried blood type of manures additional auxins arc produced as a result of their decomposition in the soil. It has been shown that β‐indolyl acetic acid is one of the auxins thus produced. Heavy dressings of organic manures may produce a considerable increase in auxin content of the soil but this increase is rapidly followed by a reduction to a value within the normal range. Moreover specially washed soils with a low auxin content show an increase in auxin content on ageing to a value within the normal range. These facts suggest the existence of a mechanism within the soil to control the soil auxin content within certain limits or suggest what is tentatively described as an “auxin balance

ISSN:0368-4075    

DOI:10.1002/jctb.5000670705

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractTests of commercial tomato varieties have shown that they differ significantly in their content of ascorbic acid, sugar and free acid. In plants grown in the open air, the level of these constituents is not directly related to the hours of sunshine or the day temperature at the time of picking. The yield of ascorbic acid from a given number of plants is more influenced by cropping capacity than by the ascorbic acid content of the individual fruits in the varieties studied.

ISSN:0368-4075    

DOI:10.1002/jctb.5000670706

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractIn this work a short account is given of researches into the measurement of the size characteristics of mineral powders by photo‐extinction methods which have led to an experimentally derived curve relating the extinction coefficient for a suspension to the size of particle of the material in suspension, for the size range 0‐50 microns. While it is not claimed that the validity of this curve is rigidly established, it is believed that it is considerably more reliable than any previously suggested and to have an accuracy sufficient for many industrial purpo

ISSN:0368-4075    

DOI:10.1002/jctb.5000670707

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractExperiments have been carried out in a small laboratory packed tower and in a wetted wall column to determine the respective contributions of the gas and liquid films to the transfer of water vapour from moist air into strong solutions of calcium chloride. Comparative tests were also made on the absorption of ammonia from air‐ammonia mixtures into dilute sulphuric acid in the wetted wall column. The experimental results have shown that in normal conditions gas drying by calcium chloride solutions may be regarded as a case of predominantly gas film limitation. This information may be used in the design of gas or air drying towers using strong calcium chloride solution as desiccan

ISSN:0368-4075    

DOI:10.1002/jctb.5000670708

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY