ISSN:0021-8871    

DOI:10.1002/jctb.5010150911

出版商:John Wiley&Sons, Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractExperimental critical temperatures and critical pressures presented in the literature for binary aliphatic hydrocarbon systems have been utilised to obtain the excess critical temperature,Tc—T′c, and the excess critical pressure,Pc—P′c, for reported compositions of these binary systems. Besides composition, these excess quantities were found to depend on α, the critical temperature parameter, and β, the critical pressure parameter.Because of the different behaviour associated with the methane‐containing binaries, these systems were treated separately. The final correlations of these excess critical quantities for non‐methane systems produced an average deviation of 0.46% for critical temperature and 2.30% for critical pressure for 63 experimental values considered; for the methane‐containing binary systems, the corresponding correlations produced a deviation of 0.93% for critical temperature and 1.10% for critical pressure from 36 expe

ISSN:0021-8871    

DOI:10.1002/jctb.5010150901

出版商:John Wiley&Sons, Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractTubes of polythene, polypropylene, furfural polymer (‘Tygon’) or polytetrafluoroethylene are normally permeable to atmospheric oxygen when deoxygenated water flows through them. Both polypropylene and Tygon can achieve a state of impermeability after prolonged contact with water, and this is due to the steady‐state water transmission through the tube‐wall becoming sufficiently vigorous to exclude the oxygen that attempts to penetrate in the opposite direction. It is shown that the achievement of oxygen impermeability by this mechanism can depend on the cross‐sectional dimensions of the tube. Hence only the smaller of two polypropylene tubes achieved impermeability to atmospheric oxygen. On account of the special conditions required for oxygen impermeability, it is considered that none of the four types of polymer tubing tested in this work is suitable for routine use in the sampling of water before microdetermination of dissolv

ISSN:0021-8871    

DOI:10.1002/jctb.5010150902

出版商:John Wiley&Sons, Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractThe effects of temperature, acid concentration, and amount of acid on the rate of removal of olefins from benzene solution by means of sulphuric acid have been examined. The results show that the reaction follows first‐order kinetics and they are interpreted on the basis that rates of removal are controlled both by diffusion and by reaction in the acid phas

ISSN:0021-8871    

DOI:10.1002/jctb.5010150903

出版商:John Wiley&Sons, Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractThe reaction involved is of first‐order, but prolonged action of the acid leads to return of thiophen to the organic phase. The velocity constant is directly proportional to, but the time required for maximum extraction is independent of, the amount of acid used. The presence of olefins leads to reduced amount of thiophen removed, but maximum removal is effected in a shorter time. The system does not obey the Arrhenius equation and low temperature is desirable for the proces

ISSN:0021-8871    

DOI:10.1002/jctb.5010150904

出版商:John Wiley&Sons, Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractDuring the two‐phase reaction of benzene with concentrated sulphuric acid, benzene‐soluble reaction products (gum) are derived from the polymerisation of olefins present, thiophen alone forming little

ISSN:0021-8871    

DOI:10.1002/jctb.5010150905

出版商:John Wiley&Sons, Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractThis paper describes measurements with a dropping mercury electrode of theinterfacial tensionsand differential capacitances of solutions ofN‐sulphuric acid containing small concentrations of n‐alkyltrimethylammonium bromides. Adsorption of the n‐alkyltrimethylammonium ions was indicated by decreases in the interfacial tension and the differential capacitance, the latter being the more sensitive criterion. The magnitude of these changes increased with increasing alkyl chain‐length. With the longest chains the electrocapillary maxima were displaced towards more anodic potentials.The results are briefly discussed in relation to the performance of the n‐alkyltrimethylammonium bromides as inhibitors of the acid pickling

ISSN:0021-8871    

DOI:10.1002/jctb.5010150906

出版商:John Wiley&Sons, Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractA series of aggregates of known road performance with 300‐pen. bitumen in bitumen‐macadam wearing‐courses has been examined by five different, known adhesion (stripping) tests.The results of the Static Immersion and Mallison Tests showed no satisfactory correlation with each other, with the results of other tests or with practical performance. The other three tests gave more satisfactory results which bore some relation to each other and to practical performance. The Immersion Wheel‐tracking Test gave the best general relation to practical performance provided that the effects of stability of partially stripped materials were taken into account as well as the amount of stripping. The Riedel&Weber and Immersion Compression Tests gave good correlation with road performance for mixtures not showing stripping in practice and also detected those mixtures which stripped readily on the road. With aggregates of intermediate road performance, the test results were less satisfactory. There is reason to suspect the validity of both of these tests when adhesion agents are present in the

ISSN:0021-8871    

DOI:10.1002/jctb.5010150907

出版商:John Wiley&Sons, Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractThe viscosities of eighteen tar products ranging from refined tar of 34° equiviscous temperature to electrode binder pitch of 102° softening point (Ring Ball) have been measured between wide temperature limits and within the viscosity range of 10 to 1010centipoises. The applicability of three equation forms to these results has been assessed. A simple logarithmic relationship in terms of Fahrenheit temperature is satisfactory for most products at viscosities greater than 104centipoises, but does not apply at lower viscosities or to the harder pitches. A double logarithmic viscosity/temperature relationship fits the results well, except those relating to the hard pitches, but it is insensitive and unreliable at viscosities of about 109centipoises and greater. A third equation relating the logarithm of viscosity to the fifth power of absolute temperature has been shown to apply over the full range of materials, temperatures and viscosities examined.The significance of the constants used in these equations is discussed with respect to their value in comparing the temperature susceptibility of tar products.It is shown that the correct order of viscosity of a tar product, within the range of materials and viscosities investigated, can be predicted from its softening point or equiviscous temperature and its toluene‐insoluble cont

ISSN:0021-8871    

DOI:10.1002/jctb.5010150908

出版商:John Wiley&Sons, Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractChanges in surface area and crystallite size in the interconversions of the forms of sulphated lime have been related to time and temperature conditions.The specific surface increases when hemihydrate, ‘soluble’‐γ‐ and ‘anhydrite’‐β‐calcium sulphate are formed during the thermal decomposition of gypsum. The activation is initially delayed in each dehydration stage, before the products recrystallise to their normal lattice structures. Subsequently, the specific surface decreases (and the average crystallite size increases) as each product sinters.‘Wet’ rehydration of γ‐calcium sulphate rapidly replaces the water in the zeolitic hemihydrate structure, without appreciably ageing it. The less mobile ‘dry’ rehydration in water vapour produces hemihydrate extensively aged. Both ‘wet’ and ‘dry’ conversions of hemihydrate to gypsum are completed with considerable loss of surface. The gypsum crystallinity is more rapidly developed during the ‘wet’ rehydration. Effects of additives on the rehydration and ageing of hemihydrate gypsum plasters have been similarly studied.Anhydrite ‘dry’ rehydrates only very slowly, but ages considerably. ‘Wet’ rehydration slowly produces gypsum of low crystallinity; the surface initially increases, before decreasing greatly as the rehydration accelerates. The rehydration rate finally falls as the material cont

ISSN:0021-8871    

DOI:10.1002/jctb.5010150909

出版商:John Wiley&Sons, Ltd    

年代:1965

数据来源: WILEY