摘要:

AbstractThe meaning and purpose of sampling are discussed. Results are presented from a series of road trials on the sampling of asphalt mixtures to demonstrate the importance of bias and variability introduced into test measurements by sampling. Further variability is introduced by the reduction in size by quartering of gross samples to the size required for testing; it is shown that this variability is reduced when a riffling technique is used. It is usual to adjust the measured binder and filler contents of asphalt for the disturbance caused by sampling. Evidence is presented to show that the adjustments in current use may not be well chosen and some more appropriate factors are suggested.

ISSN:0021-8871    

DOI:10.1002/jctb.5010201201

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe refractive index, density and viscosity of aqueous solutions of ammonium sulphate have been measured in the range 20‐30°. The solubility of ammonium sulphate was checked over the range 20‐45° by measuring saturation temperatures in a simple apparatus. The same technique was also used for nucleation studies; the maximum allowable undercoolings with and without seed crystals range from ˜ 3.5° and 5°, respectively, for fast cooling rates, to ˜ 1.5 and 3.5° for slow.Growth rates of two major faces (100) and (001) of ammonium sulphate crystals were measured in a flow cell. The (100) face growth rate is directly proportional to the concentration driving force and independent of solution velocity, whereas that of the (001) face appears to be a second‐order process and slightly veloci

ISSN:0021-8871    

DOI:10.1002/jctb.5010201202

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe solubility of carbon in sodium over the range 600‐950° may be expressed by the equation: log sol. = 7.20‐5465/T where solubility is in ppm andTin °K.From plots of carbon activityversusconcentration, and from observations that oxygen does not affect carbon solubility, it is proposed that carbon dissolves in sodium as single

ISSN:0021-8871    

DOI:10.1002/jctb.5010201203

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe decomposition under vacuum of the hydroxides of calcium, strontium and barium was investigated by differential thermal analysis (DTA), electrothermal analysis (ETA) and dilatometry.The results suggest that the rate of sintering of calcium oxide is initially governed by the formation of a pseudo‐hydroxide lattice; rapid sintering occurs only after conversion of this to the true oxide. Compacts of the oxides of strontium and barium show a remarkable resistance to sintering at temperatures up to 1000°. It is proposed that the sintering may have been inhibited by the presence of trace amounts of calcium oxide and strontium oxide formed by decomposition of impurities present in the samples of strontium and barium hydroxides, respective

ISSN:0021-8871    

DOI:10.1002/jctb.5010201204

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe decomposition under vacuum of the carbonates of calcium, strontium and barium was investigated by differential thermal analysis (DTA), electrothermal analysis (ETA) and dilatometry.The results indicate that the rates of sintering of the oxide produced by the decomposition of the corresponding carbonate are in the order predicted by their respective Tammann temperatures, i.e. BaO>SrO>CaO. DTA studies on the decomposition of samples of barium carbonate have shown that great care must be taken to ensure that the decomposition is carried out under the highest vacuum attainable, in order to eliminate the formation of a basic carbonate. Further evidence of the formation of free barium by this decomposition process is also reported.

ISSN:0021-8871    

DOI:10.1002/jctb.5010201205

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractAnalysis of methanolic extracts of wool grease for nitrogen and phosphorus, and laminar chromatography of the ether‐insoluble fraction obtained from the methanol‐soluble portion, showed that wool wax does not contain phospholipids but it does contain traces of polypeptides and inorganic phosphate. These results conflict with the results of other workers, but possible explanations of false conclusions drawn from the latter results are gi

ISSN:0021-8871    

DOI:10.1002/jctb.5010201206

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractA study was made of physical and chemical changes that take place during bleaching ofRangeeniandKusmi, the two main varieties of lac, by the improved hypochlorite bleaching process. The physical changes studied include life, flow and keeping quality. The chemical changes observed were oxidation, addition, substitution and partial hydrolysis. Fractionation and intrinsic viscosity, however, showed little overall molecular change.

ISSN:0021-8871    

DOI:10.1002/jctb.5010201207

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY