摘要:

AbstractThe air‐entraining actions of a number of anionic surfactants in cement pastes were studied in order to determine whether precipitated calcium surfactants influence the air‐entrainment process. Air contents of pastes containing both soluble and precipitated calcium surfactants were higher than those containing only soluble calcium surfactants, thus indicating that precipitated material contributed towards air‐entrainment. It was shown further that the precipitated calcium surfactant could re‐dissolve appreciably during mixing and supply additional surfactant ions in solution to replace those adsorbed on cement. It was concluded that these additional ions contributed to air‐entrainment by further adsorption on cement particles and by augmenting the foam capacity of the mix

ISSN:0375-9210    

DOI:10.1002/jctb.5020210301

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA study has been made of the effect of fluoroaluminium ions on the retarded hydration of calcium sulphate β‐hemihydrate brought about by amino acid retarders. If sufficient fluoroaluminium ions are present (∼0.02–0.03% Al as co‐crystalline AlF2−5in the hemihydrate), the hemihydrate becomes insensitive to retarder addition because the latter forms stable chelates with the fluoroaluminate ions. The retarder is thus effectively deactivated because the chelates are not sufficiently strongly adsorbed on to the faces of the growing gypsum crystals to influence the rate of advance of the gr

ISSN:0375-9210    

DOI:10.1002/jctb.5020210302

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe sorption of sulphur dioxide by a wide range of leather samples has been investigated at a concentration of ∼ 100 μg/m3using sulphur‐35 dioxide. In general, the sulphur dioxide was sorbed evenly over the leather surfaces, the sorbed sulphur being water‐soluble. The position on the hide from which the leather was taken had no significant effect on the amount of sulphur dioxide sorbed. The total uptake of the gas was reduced by the application of a finish and by dyeing. The penetration of sulphur dioxides into the samples was influenced by the nature of the organic retanning process used, condensed tannins leading primarily to surface sorption. Leather greases were also shown to reduce penetration of sulphur dioxide. Some implications of these results in the degradation of leathers by atmospheric sulphur dioxide are dis

ISSN:0375-9210    

DOI:10.1002/jctb.5020210303

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA study is described of both anodic and cathodic fluidised‐bed fuel‐cell electrodes operating with dissolved reactants. Two different trends were observed. With cathodes, the apparent polarisation decreased with increase in fluidisation and with anodes the apparent polarisation increased with increase in fluidisation. These effects are thought to be due to different reaction mechanisms and the different nature of the bed materi

ISSN:0375-9210    

DOI:10.1002/jctb.5020210304

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA survey of the recent progress in the field of high energy non‐aqueous batteries is presented. The newest batteries show some improvements on the existing ones although numerous problems still remain. The use of electrolytic solutions with higher specific conductivities and the use of cathode materials virtually insoluble in these electrolytes has been introduced. Some attention has also been given to systems useful in secondary cells. As a result of these recent researches, batteries capable of sustaining quite high current densities on discharging and having a better shelf‐life have been produ

ISSN:0375-9210    

DOI:10.1002/jctb.5020210305

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractData are presented concerning the production of gaseous and liquid products from coal. The processes considered include pyrolysis, dissolution in solvent with and without the application of ultrasonic energy, batch hydrogenation, and continuous hydrogenation. The products are compared with respect to both quantity and type. Activation energies are presented and mechanisms discussed. Coal hydrogenation in the presence of an appropriate catalyst shows very great promise as a means of converting coal to liquid and gaseous fuels. Yields of 30% high octane gasoline, 5% diesel oil, 35% high Btu gas, and 30% char, on a weight basis, have been achieved.

ISSN:0375-9210    

DOI:10.1002/jctb.5020210306

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe gas‐phase alkylation of aromatic hydrocarbons was studied using various solid catalysts. The alkylation of xylenes with propylene produced tetra‐alkylbenzenes whose structures suggest that these products will be suitable for the preparation of pyromellitic a

ISSN:0375-9210    

DOI:10.1002/jctb.5020210307

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractDimerisation of propylene and double‐bond isomerisation of olefins with a new nickel catalyst are describe

ISSN:0375-9210    

DOI:10.1002/jctb.5020210308

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY