ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12545.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

The effects of additions of urea, monobasic ammonium phosphate, dibasic ammonium phosphate, sodium ammonium phosphate, ammonium nitrate, and ammonium chloride on some physical properties of an unfired and a fired illitic shale of high carbonate content were studied. X‐ray examination of the Devonian shale showed that illite was the predominant clay mineral; there was also some chlorite. Scum was reduced and a clean surface was produced by additions of ½ to 1% of ammonium phosphate. Urea did not reduce scum. Ammonium nitrate and ammonium chloride increased scum. Fired absorption was increased by monobasic ammonium phosphate, ammonium chloride, and ammonium nitrate, whereas dibasic ammonium phosphate, sodium ammonium phosphate, and urea produced only slight changes. The workability of the tempered shale was decreased by 1% additions of monobasic ammonium phosphate, ammonium chloride, and ammonium nitrate. The presence of the chloride or the nitrate ions caused thixotropy and the phosphate ion caused dilatency. All ammonium additions shortened the time for complete oxidation of the shale specimens. Ammonium chloride was the best oxidation accelerator. Only the 1% addition of ammonium chloride increased the frost resistance of specimens fired to cone 07. All specimens fired to cone 02 were frost resistant and ammonium additions had no effect. The hydration of lime on specimens fired to cone 07 was not affected by additions of ammonium salts, Firing to cone 02 reacted most of the free lime and held hydration to a minim

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12546.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

The modes of fracture and slip in cemented carbides were observed. Fracture and slip patterns in cemented carbides were found to vary with the microstructures which in turn were determined by the relative surface energies of various phases. The influence of particle size and metal binder content in cemented Tic and WC was also investigated. The fracture and slip in these systems are discussed in terms of the role of the metal film surrounding the carbide grains.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12547.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

An unsteady‐state method was employed for measuring values of Biot's modulus and the thermal diffusivity of pure dense alumina in the temperature range 1500° to 1800°C. Limits were established for the possible range of values of diffusivity, and corresponding values of thermal conductivity were calcula

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12548.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Previous studies of the kinetics of dehydroxylation of kaolinite and halloysite point to first‐order reactions, in approximate conformity with the Arrhenius relation. Isothermal weight‐loss measurements have shown that the rate constants are markedly dependent on factors such as specimen size, shape, and compaction. A technique has been developed for determining the reaction kinetics of infinitely thin disk‐type specimens. The reactions are then strictly first order and the Arrhenius relation is obeyed. Activation energies of 65 and 55 kcal. per mole are obtained for kaolinite and halloysite, respectively. Comparison is made between the behavior of kaolinite and halloysite on the one hand and of macrocrystalline anauxite on the other. For anauxite, nucleation and growth of nuclei produce a sigmoid‐type reaction curve, but for the fine‐grained minerals it is believed that nucleation alone is the rate‐controlling process. The dependence of the reaction rate on geometrical factors is attributed to the retention of water vapor within the powder specimen. The influence of water vapor on these reactions is discusse

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12549.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Thermal expansion data for W–MgO and AlSiO2compositions are not simply averages of end‐member values but agree quantitatively with calculations based on the assumption of substantial residual microstresses resulting from the restraint of each phase on cool

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12550.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

The total sulfur in glass in the range 0.01 to 1.0% SO3can be rapidly estimated by an induction furnace combustion method using standard commercial equipment. The results compare favorably with the classical barium sulfate precipitation procedure and with X‐ray fluorescence analysis. The sulfide sulfur in glass can be determined by solution of the sample with hydrofluoric acid in the presence of silver ion, followed by titration of the amount of silver precipitate

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12551.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

The literature on the mechanism of the slipcasting process is reviewed. An equation is developed to give a quantitative description of the rate at which the clay layer is deposited from the slip in the filter‐pressing and slip‐casting processes. Certain factors in the equation can be evaluated by the application of the Kozeny equation. Agreement between the calculated and observed rates of solids deposition is satisfactory and confirms that the mechanism in both processes is simple dewater

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12552.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12553.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY