摘要:

Samples of the isotropic hexahydrate of tricalcium aluminate were dehydrated in a current of dry air at various temperatures up to 1050°. The water retained and the lime liberated were determined. The results of earlier preliminary studies in this laboratory were confirmed. At low temperatures an isotropic hydrate of the composition, having a refractive index of 1.543 ± 0.003, is formed. This hydrate is stable in dry air up to a temperature of approximately 275° and when once formed at lower temperatures has a very slow rate of decomposition below 350°. On continued dehydration above 275° decomposition occurs with the liberation of calcium oxide. Between 550° and 950° quantitative decomposition occurs into calcium oxide and an aluminate of the composition 12CaO∙7Al2O3. In the upper part of this temperature range prolonged heating causes slow recombination of the solid decomposition products, and above 950° this effect becomes marked. Dehydration of the hexahydrate in a current of dry nitrogen gives similar results. The experiments indicate that the systemwould serve as an efficient drying agent at temperatures below 100°

ISSN:1923-4287    

DOI:10.1139/cjr41b-017

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

A heat-conductivity, low-pressure gauge based on the rate of sublimation of solid carbon dioxide is described. The gauge, which also serves as a trap in the vacuum line, is sensitive enough for most purposes. It is extremely simple and inexpensive to construct and operate.

ISSN:1923-4287    

DOI:10.1139/cjr41b-018

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

p-Nitro-p′-hydroxyazobenzene,p-hydroxyazobenzene, andp-aminoazobenzene have been oxidized with 30% hydrogen peroxide. It has been found that in the case of the first two compounds prolonged treatment (25 hr.) disrupts both benzene rings and results in their complete oxidation to carbon dioxide, water, and nitrogen, or oxides of nitrogen. Oxidation of the third compound is not complete after six days.

ISSN:1923-4287    

DOI:10.1139/cjr41b-019

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

The thiochrome method as applied to foodstuffs by Pyke (10) has been modified to permit the use of the fluorimeter described by Froman and McFarlane (3). Interfering pigments are destroyed by adding hydrogen peroxide to the "blank" and test solutions before extracting with isobutanol. Hydrogen peroxide does not oxidize thiamine to thiochrome nor does it destroy the latter. The procedure described is based on a reinvestigation of the various methods proposed for extracting thiamine from tissues and also of the optimum amount of each reagent used in the thiochrome test.

ISSN:1923-4287    

DOI:10.1139/cjr41b-020

出版商:NRC Research Press    

年代:1941

数据来源: NRC