摘要:

Commercial, Underwriters', and A grades of asbestos cloth begin to lose strength as soon as heat is applied. On heating for five minutes at 300 °C. these three grades of asbestos cloth lose approximately 60, 35, and 25% of their original (conditioned) breaking strength, respectively. Charts are given showing the effect of heating, at temperatures up to 600 °C., for periods up to one hour.

ISSN:1923-4287    

DOI:10.1139/cjr41b-009

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

A systematic study of official methods of analysis of maple sap products has been made in order to investigate their validity as criteria of the purity of these products.A new value, the manganese number, is being proposed as a safer criterion but, in some cases, even this may lead to error.The conclusion of the writers is that, at the present time, it cannot be stated with certainty that a maple product is 100% pure; it is therefore necessary that research work be continued in order to find a criterion of purity that would be valid in every case.

ISSN:1923-4287    

DOI:10.1139/cjr41b-010

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

With the object of determining the factors responsible for the inapplicability of the ideal equation of the freezing curve,a number of experimental determinations have been carried out on the system naphthalene–p-nitrophenol. These were: (i) specific heat, (ii) heat of fusion, (iii) heat of mixing, (iv) vapour pressure, (v) vapour composition, (vi) density, (vii) surface tension, (viii) viscosity.The conclusion is arrived at that the discrepancy is due principally to the invalidity of Raoult's law in this case. Since the deviation is positive with respect to both components, it cannot be ascribed to compound formation in solution. Apart from the deviation from Raoult's law, the solution does not exhibit marked abnormality.The data obtained also permit of the complete, or almost complete, construction of thep–t–xmodel for this system.

ISSN:1923-4287    

DOI:10.1139/cjr41b-011

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

A practical method for determining the concentration of T.N.T. in workroom atmospheres has been developed and has been given successful field tests. The accuracy of the method described is approximately ± 10%. The method is a comparative one, depending upon the red coloration produced when 2,4,6-trinitrotoluene in acetone is treated with a solution of sodium hydroxide in water. The stability of the coloration has been studied and the optimum conditions of temperature and concentrations of reactants have been determined. In addition the range of colour that allows the most accurate comparison has been evaluated. Minor refinements are at present in progress with a view to increasing the accuracy of the test.

ISSN:1923-4287    

DOI:10.1139/cjr41b-012

出版商:NRC Research Press    

年代:1941

数据来源: NRC