摘要:

This investigation deals with the reaction of ethyl iso-urea with acetyl-acetone, oxalacetic ester, acetone-dicarboxylic ester, and acetyl-pyruvic ester. Several pyrimidines have been synthesised. So far, the condensation of acetyl-pyruvic ester has yielded only gums which could not be purified or converted into crystalline substances.

ISSN:1923-4287    

DOI:10.1139/cjr29-018

出版商:NRC Research Press    

年代:1929

数据来源: NRC

摘要:

Paramoeciumwas irradiated with monochromatic light and it was found that rays of different frequencies have specific effects upon its growth. Certain frequencies in the red, the yellow and the near ultra-violet parts of the spectrum were found to stimulate growth; some as in the green and in the far ultraviolet beyond 3000Å retarded it, and even killed the organism at a very low intensity. Other frequencies retarded or stimulated growth during early exposure and later produced the reverse effects.

ISSN:1923-4287    

DOI:10.1139/cjr29-019

出版商:NRC Research Press    

年代:1929

数据来源: NRC

摘要:

An examination of commercial hot water heaters and steam generators of the electric water resistor type operating on alternating current shows that hydrogen and oxygen are generated within the electrode chamber. Current density is found to be the primary factor in the A.C. electrolysis of water at low voltages. At high voltages, arcing on the electrodes also results in the decomposition of the water. A critical current density exists for metallic electrodes below which electrolytic gases are not produced but above which all the current is utilized in decomposing the water into hydrogen and oxygen in accordance with Faraday's Law for continuous current. This critical current density varies with the nature of the electrode material, the temperature of the electrolyte and the frequency of the alternations: the higher the frequency the higher the critical current density. The storage capacity of the electrode for hydrogen and oxygen known as the "electrolytic capacity" is constant for copper but varies with the quarter-wave area for platinum and silver. At constant quarter-wave area the electrolytic capacity decreases to a minimum with increasing frequency. A difference in the phase for current and voltage is observed, the current leading the voltage. Wave distortion occurs in the case of platinum and copper electrodes. High voltage arcing by an alternating current produces a thermal decomposition of the water quite independent of A.C. electrolysis. The rate of decomposition by arcing is primarily dependent upon the rate of consumption of electrical energy. Hydrostatic pressure in the electrode chamber inhibits arcing. The application of the results to the design and operation of electric steam generators and domestic heaters is discussed, and the explosion hazard connected with the generation of electrolytic gas is also commented upon, a means being suggested for reducing the danger.

ISSN:1923-4287    

DOI:10.1139/cjr29-020

出版商:NRC Research Press    

年代:1929

数据来源: NRC

摘要:

A study was made of the effect of steam-curing at various temperatures between 50° and 200 °C. on the resistance of Portland cement mortars to the action of solutions of the sulphates of sodium, magnesium and calcium. The methods used consisted in comparing the expansion of steam-cured and untreated mortar specimens during exposure to the solutions, and in determining the changes in the tensile strength of the more resistant mortars after long periods of exposure.A laboratory study of steam-curing as a remedy for the action of sulphates ("alkali") on Portland cement mortars, was made by determining the effect on the stability of the mortar as indicated by changes in volume and in tensile strength on exposure to sulphate solutions at 21 °C. The effect of steam-curing on the tensile and compressive strength of mortars and concrete was also studied.

ISSN:1923-4287    

DOI:10.1139/cjr29-021

出版商:NRC Research Press    

年代:1929

数据来源: NRC