ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16281.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

摘要:

ABSTRACTAfter a brief review of the history of former operations and the general layout of a mine, the methods used in National Mine No. 21 at East Canton, Ohio, are described in detail. The plan of the mine, panel layout, and the removal of an individual pillar are described with illustrations showing how more than 80° of the clay is recovered. Conditions and results in a number of other mines are given with illustrations of the methods. The relation of a high percentage of extraction to costs and safety is discussed

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16282.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16283.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16284.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16285.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

摘要:

ABSTRACTA new test was developed for comparing the strains existing between different glazes or other ceramic finishes and the bodies to which they are applied. By its use these strains may be so adjusted that the finishes will be in suflicient compression to prevent crazing from subsequent expansion of the body without causing initial shivering. The new test is particularly valuable because the measuremen&are made on combinations of glaze and body prepared and treated almost exactly like those intended for regular use and because of the simplicity and cheapness of the apparatus required. A modification of the test provides a comparison of the moisture expansions of different bodies.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16286.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

摘要:

ABSTRACTA torsional method is described and some results given of the study of the viscosity of porcelain in the temperature range 700 to 800°C

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16287.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

摘要:

ABSTRACTThe relative solubilities were determined by measuring the increase inpHvalue that results from the solution of feldspar in water. The maximum time used was 48 hours. Twenty‐gram samples of feldspar were immersed in 200 cc. of water in volumetric flasks. ThepHvalues were determined colorimetrically after definite intervals of time. Care was taken to, exclude atmospheric carbon dioxide.The conclusions are (1) there exists no definite relation between the ratio K2O/Na2O of a feldspar and its solubility in water; (2) certain peculiarities of the feldspars are carried throughout the work; (3) both high soda and high potash feldspar have almost equal solubilities in this work; (4) the data obtained indicate that there may be suffi‐ cient increase inpHvalue to affect the viscosity of casting slips. The relations betweenpHincrease and time are shown by graphs and represented by equations. The equations are of the formH=T/(a+bT) and no relation exists betweenaandband the ratio K20/Na2O. The error of the work is estimated to be approximately

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16288.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

摘要:

ABSTRACTThis paper includes a triaxial diagram for the potash series, containing two good glass areas in contrast with a single area in the soda series.3One area is in the region of low beryllia and high silica; the other in the region of high beryllia and low silica. The latter contains the better glasses. Areas are also shown in which the tendency to increase silica produces opalescence while that toward an increase of beryllis promotes divitrification. Great difficulty has been experienced in obtaining pure beryllium oxide. Material that was supposedly pure contained as much as 20° of moisture. Difficulty has been encountered also through such impurities as the oxides of iron and manganese. One sample of supposedly C.P. beryllium oxide contained over 90° alumina. Optical data are not yet available. As was the case with the sodium beryllium silicates. so here again the announcement is the first of the potassium‐beryllium glasses, t o the best knowledge of the auth

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16289.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16290.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY