摘要:

AbstractThe need to test experimentally determined vapour–liquid equilibrium data for thermodynamic consistency is now widely recognised. This paper is concerned with general integral tests based on the Duhem–Margules equation and not with particular algebraic solutions of that equation. A family of ‘symmetrical‐area’ tests is presented; these new tests are more powerful tools for the examination of experimental data than the area tests previously developed by the author, and can be used to examine part of a composition range and to identify regions of poor observation. Moreover, the tests can sometimes be used to identify the quantities that are in error. They are applicable to systems with miscibi

ISSN:0021-8871    

DOI:10.1002/jctb.5010181001

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractIn the electrochemical machining process the electrolyte, in addition to conducting the required current, has the added function of removing the electrode reaction products—hydrogen from the cathode and metal oxide from the workpiece. This function is facilitated if close control is maintained over the pH of the electrolyte. Titanjum halides form clear solutions if the pH is less than 2 but precipitate if the pH exceeds 3·7. Niobium and tantalum halides were also studi

ISSN:0021-8871    

DOI:10.1002/jctb.5010181002

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractA quantitativeX‐ray diffractometric method using corundum (α‐Al2O3) as an external standard has been developed for estimating uncombined MgO in high‐magnesia cement clinkers. For these clinkers, separation of the silicate phases by selective hydrolysis is not necessary.TheX‐ray method has provided results reproducible to ± 0·5% and it compares favourably with chemical methods. The non‐destructive nature of the test and its rapidity are the mai

ISSN:0021-8871    

DOI:10.1002/jctb.5010181003

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractThe surface properties of a range of aluminas, obtained by calcination of crystalline and gelatinous aluminium hydroxides at temperatures from 300° to 1000° and characterised byX‐ray powder diffractometry, have been examined by nitrogen adsorption.On calcination the hydroxides exhibited two distinct types of behaviour which can be related to their texture. Crystalline hydroxides underwent a pronounced activation, the increased surface area being almost wholly confined to the small pores (micro and transitional pores) formed on dehydration. Gelatinous hydroxides, on the other hand, had high surface areas before calcination and these underwent a progressive diminution in the temperature range studied.The structures obtained on calcination depended to a marked degree on the crystallinity of the starting materials. Between 500° and 800°, the amorphous hydroxide and poorly organised pseudoboehmites gave ill‐defined γ‐aluminas whereas the crystalline trihydroxides gave well‐defined η‐ and θ‐aluminas. At 1000°, the product from the amorphous hydroxide still retained a surface area of 132 m2/g, this high residual area being in character with the slowness of the conversion to δ‐and α‐alumina.An empirical approach is used to analyse the adsorption data in terms of three mechanisms of adsorption: monolayer‐multilayer coverage, capillary condensa

ISSN:0021-8871    

DOI:10.1002/jctb.5010181004

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractTo enable further work to be carried out on the hydration of hemihydrate plasters, materials purer than the available commercial plasters and with reproducible properties were required. As a first stage in the attempted preparation of such materials, the process variables in the autoclave dehydration of gypsum were investigated. Methods of treating the gypsum to ensure reproducibility of particle size and for removing other hydrates of calcium sulphate from the prepared materials were developed. It was found possible to prepare samples of a purer hemihydrate, and the reproducibility of the properties of this material has been studied.

ISSN:0021-8871    

DOI:10.1002/jctb.5010181005

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

ISSN:0021-8871    

DOI:10.1002/jctb.5010181006

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractIn the course of optimisation studies on the cracking of methane in anomalous glow‐discharges (50 Hz a.c., maximum potential 2000 V, maximum current 300 mA) at sub‐atmospheric pressures (20–270 torr), high yields (up to 80% per pass) of acetylene were obtained. The effects of pressure, contact time, reactor geometry, cooling of reactor wall, pre‐heating of reactant, and solid‐ and vapour‐phase catalysis, as well as the role and mode of decomposition reactions, have been investigated. Further evidence was obtained on the role of electron activation in these reactions. By optimisation of the reaction conditions, it proved possible to achieve a considerable reduction in the specific consumption of electr

ISSN:0021-8871    

DOI:10.1002/jctb.5010181007

出版商:John Wiley&Sons, Ltd    

年代:1968

数据来源: WILEY