摘要:

The effect of substituting silica gel for a portion of the Portland cement in standard and graded-sand mortars on the expansion and loss in strength of the mortars in sulphate solutions was determined. Portland cement silica gel sand mortars were cured in steam at 100 °C. and the effect on their sulphate resistance measured; the behavior of lime-silica gel sand mortar in solutions of sodium and magnesium sulphate was also studied. It was found that the addition of silica gel to the mortar, very effective in preventing expansion and maintaining the tensile strength of the mortar in solutions of sodium, and calcium sulphate, was not so effective in solutions of magnesium sulphate. Steam-cured mortars containing silica gel to the extent of 20% of the cement present showed a slightly greater resistance to the action of solutions of sodium and calcium sulphates, but less resistance in solutions of magnesium sulphate, than similar steam-cured mortars containing no silica gel. Lime-silica gel sand mortars behaved very similarly in sulphate solutions as Portland cement mortars containing silica gel. The possible causes of the effects produced by the addition of silica gel to Portland cement mortars are considered, and several explanations discussed.

ISSN:1923-4287    

DOI:10.1139/cjr29-022

出版商:NRC Research Press    

年代:1929

数据来源: NRC

摘要:

In the preparation of aluminum chloride by the action of hydrogen chloride on the metal, hydrogen chloride is adsorbed and can be recovered to the extent of about 9 cc. per gram. After sublimation in nitrogen and re-sublimation in hydrogen chloride, however, the amount of adsorption is smaller and irregular. The adsorbed gas is not removed by a stream of nitrogen at room temperature. The activities in the Friedel and Crafts reaction of various preparations of aluminum chloride and of ferric chloride and of mixtures of these were determined; the order of decreasing activity was found to be as follows: a mixture of aluminum chloride and ferric chloride, aluminum chloride made by the action of hydrogen chloride on aluminum, aluminum chloride made by the action of chlorine on aluminum, a mixture of aluminum chloride and partially reduced ferric chloride, ferric chloride, and partially reduced ferric chloride. The most striking result of the measurements is that although ferric chloride alone has an activity of only about one-third that of aluminum chloride, an approximately equimolecular mixture of the two has an activity somewhat greater than that of pure aluminum chloride.

ISSN:1923-4287    

DOI:10.1139/cjr29-023

出版商:NRC Research Press    

年代:1929

数据来源: NRC

摘要:

The work is an amplification of the method introduced previously by Boyle and Lehmann, and illustrates the application of the theory of monochromatic interference spectroscopy of optics to sound. By experiments with lead, duralumin and paraffin, at different high frequencies, the effects of both high and low reflecting powers are shown, and also the possible influences of harmonics. It is also shown that in travelling through thin discs the velocity of the waves is given more accurately by the bulk modulus of elasticity than by Young's.

ISSN:1923-4287    

DOI:10.1139/cjr29-024

出版商:NRC Research Press    

年代:1929

数据来源: NRC

摘要:

The Island of Ceylon is composed almost entirely of crystalline rocks of Archean or pre-Cambrian age. In the extreme north these are overlain by limestones of Miocene or later age. At one point on the northwest coast a very small area of Jurassic rocks lies on the surface of the coastal plain.The ancient crystalline rocks resemble in many respects the Grenville series of the Canadian Shield. They are largely biotite gneisses, interstratified with which are at least two great beds of white crystalline limestone, often dolomitic, with associated beds of quartzite and of sillimanite-bearing rocks of undoubted sedimentary origin. Charnockite and allied rocks are present also in large amount, especially in the higher parts of the island. The petrography of these rocks is described, and is illustrated by a series of chemical analyses, the first that have been made of the rocks of this island. In structure Ceylon is a portion of a great syncline, deeply eroded, closed on the south, open to the north, where it plunges beneath the Miocene cover.Three distinct plains of denudation can be clearly recognized in Ceylon. The coastal plain, about 100 ft. above sea-level, a second plain at about 1,600 ft., and a third at 6,000 ft. above sea-level.The paper presents the first account which has been given of the geological structure of the island, and the accompanying geological map of the island is the first which has been prepared.

ISSN:1923-4287    

DOI:10.1139/cjr29-025

出版商:NRC Research Press    

年代:1929

数据来源: NRC