摘要:

The equilibrium sorption of a purified direct dye on natural cotton yarn has been determined over a range of dye-bath concentrations (20 to 175 mgm. of dye per litre of solution) and temperatures (75° to 90 °C.). The liquor-to-yarn ratio in the dye bath, which contained sodium chloride (4.00 gm. per litre), was sufficiently high to permit the concentration of dye in solution to remain essentially constant throughout a dyeing experiment. The dye was removed from the skeins using a pyridine–ethanol–water solution, and the concentration of dye in the latter determined spectrophotometrically.Differential heats of dyeing may be calculated from the results obtained. For an equilibrium sorption of 475 mgm. of Calcodur Blue 4GL per 100 gm. of natural cotton yarn, the value of 15 kgm-cal. per mole was found, and it is shown that the differential heat of dyeing increases as the value of the equilibrium sorption decreases. The results are interpreted in the light of the modern view of the structure of cellulose.

ISSN:1923-4287    

DOI:10.1139/cjr47f-038

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

Experimental studies carried out on a limited number of hens infected orally withS.bareillyindicated that occasionally such hens may lay contaminated eggs. Using the estimated numbers ofS.bareillyin the feces as the criterion of infection, considerable variation in susceptibility was evident, the carrier period ranging from 5 to 40 days. The organisms were recovered from the intestinal tract and in one instance from the spleen. The apparent development of resistance to repeated oral inoculation was demonstrated. Experiments of a similar nature were made with hens infected orally withS.oranienburg. No contaminated eggs were found, though in this case low egg production resulting from some of the hens moulting reduces the significance of this finding. Fecal counts were lower than those obtained from theS.bareillyinfected hens.S.bonariensiswas isolated from the feces of two hens during this experiment.

ISSN:1923-4287    

DOI:10.1139/cjr47f-039

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

Slow combustion experiments by conventional laboratory methods show that metallic dopes such as the iron and nickel carbonyls and tetraethyl lead act as antioxidants in respect of the liquid paraffins present in engine fuel, the effect being especially marked at high temperatures. Such an effect failed to account for the results of certain engine experiments which could be interpreted only on the assumption that the metallic dopespromotedoxidation of the 'end gas' which is known to be the seat of knock.The inconsistencies mentioned justified an investigation of conventional laboratory methods of measuring rate of oxidation. This led to the design of a small scale flow method reaction chamber in which a typical paraffin, such as pentane, containing iron carbonyl in small concentration and mixed with air in combining proportions could be oxidized to final products, without explosion, in a time of exposure of one second or less at temperatures rising to 700 °C. Oxidation of the doped pentane was to the final products, carbon dioxide and steam, at all temperatures of reaction, rate of formation of carbon monoxide being barely measurable. On the other hand, the oxidation of pentane alone was accompanied by a profuse liberation of aldehyde, reaching a maximum rate at about 400 °C. and giving a negative temperature coefficient of reaction over the range 400° to 500 °C. Oxidation of the pentane alone occurred at a much lower rate, over the high temperature range, than when it contained iron carbonyl in the usual small proportion (of 1%).The new reaction chamber was used less successfully in demonstrating the effect of tetraethyl lead to promote the oxidation of pentane owing to difficulties arising from the properties of lead. A measurable promoting effect was, nevertheless, obtained at all temperatures of reaction.The text has been restricted to an account of the development of a novel type of reaction chamber and to oxidations of pentane necessary for the purpose. The chamber is of more general application.

ISSN:1923-4287    

DOI:10.1139/cjr47f-040

出版商:NRC Research Press    

年代:1947

数据来源: NRC