摘要:

AbstractThe rate of catalytic oxidation of sulphur dioxide on the surface of mild steel, aluminium sprayed and aluminized steel is reported. The effect of variation in temperature, gas velocity and concentration of sulphur dioxide has been measured. The presence of water vapour has been shown to inhibit catalytic oxidation on the surfaces tested. The catalytic activity of mild steel increases considerably upon exposure; aluminium sprayed specimens exhibit a maximum in catalytic activity after 7–12 hours' exposure with a decrease upon further exposure; aluminized specimens show constant catalytic activity. Coating steel with aluminium considerably reduces the rate of catalytic oxidation of sulphur dioxid

ISSN:0368-4075    

DOI:10.1002/jctb.5000671001

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractMethylene blue inhibits nitrification and denitrification during the incubation of effluents diluted with unchlorinatcd well water at 65° F. A modification of the dissolved oxygen absorption test for polluted waters is based on this finding

ISSN:0368-4075    

DOI:10.1002/jctb.5000671002

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractMolybdenum forms a green precipitate with dithiol (4‐methyl‐1: 2‐dimercaptobenzene) in acid solutions and this precipitate is soluble in amyl acetate, giving an intensely coloured solution. This reaction is the basis for an extractive method for the determination of small amounts of molybdenum, of the order of 0.2 to 25 μg., occurring in plant materials. The sample is digested with nitric, sulphuric and perchloric acids, and copper extracted with dithizone and determined as usual, if so desired. The digest is then acidified and molybdenum, along with certain other metals, extracted by means of cupferron and chloroform. After the destruction of cupferron the molybdenum‐dithiol complex is precipitated, extracted into amyl acetate and its absorption determined in a photoelectric colorimeter. The method is accurate and extremely sensitive. Since it enables the determination of both copper and molybdenum in the same digest, it represents an economy of time and reagents when both determinations are

ISSN:0368-4075    

DOI:10.1002/jctb.5000671003

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractA method is described of quantitatively extracting the pyrethrins from undried pyrethrum flowers, using petrol ether only as solvent. The flowers are ground in a rod mill with the solvent and then extracted in three stages. Samples of the same flowers are dried by natural and by the most favourable artificial means, and a third sample in a commercial drier. The total pyrethrins in the undried and the dried flowers are compared on a moisture‐free basis. The same procedure is applied to three strains of Kenya‐grown flow

ISSN:0368-4075    

DOI:10.1002/jctb.5000671004

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractMethods of determining the more important metals occurring as contaminants in foodstuffs arc discussed and, in each case, a satisfactory procedure indicated. Views on the question of statutory limits are also presented.

ISSN:0368-4075    

DOI:10.1002/jctb.5000671005

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractThe paper discusses the toxic effects due to the intake of arsenic, lead, copper, zinc, and tin, and mentions some of the findings, recommendations, and proposals of authorities in connexion with public health.

ISSN:0368-4075    

DOI:10.1002/jctb.5000671006

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractAbsolute measurements of the Theological properties of caulking compounds designed for use with hand or air pressure guns are described. The methods used arc the tube plastometer, for extension measurements, and the divided cylinder plastometer, which can be used for measurements at stresses both above and below the yield value for continuous flow. Below this yield value irreversible deformation occurs, but the rate of shear decreases continuously as shear proceeds. Above the yield value the behaviour approximates to that of a Bingham plastic body complicated, in some instances, by thixotropy. The results obtained have been applied to the practical problems of filling and the use of hand pressure guns. The temperature dependence of flow properties has also been studied.

ISSN:0368-4075    

DOI:10.1002/jctb.5000671007

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY

摘要:

AbstractThe ultra‐violet absorption spectrum of a very pure specimen of dehydrothio‐p‐toluidine (4′‐amino‐2‐phcnyl‐6‐methyl benzthiazole), which was measured by photographic spectrophotometric technique and redetermined with a Beckman photoelectric spectrophotometer, shows a strong absorption band at 345 mμ. and a rudimentary band at 260 mμ. Acetylation and benzal condensation of the 4′‐amino group result in a shift of maximum to the region of shorter and longer wave length respectively, and substitution of a p‐NMc, group in the 4′‐benzylidcncaminc substituent results in a considerable increase in intensity accompanied by the appearance of a subsidiary maximum close to the rudimentary band in dehydrottuo‐p‐toluidine. Replacement of the 4′‐amino group by hydroxyl is accompanied by a shift of absorption to shorter wave length with loss of intensity, both of which arc further affected

ISSN:0368-4075    

DOI:10.1002/jctb.5000671009

出版商:John Wiley&Sons, Ltd    

年代:1948

数据来源: WILEY