ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1933.tb16940.x

出版商:Blackwell Publishing Ltd    

年代:1933

数据来源: WILEY

摘要:

ABSTRACTNew instruments and equipment are described for the measurement of the electrical conductivity of glass at room temperatures. The accuracy of the method is discussed and certain precautions are specified for this type of measurement. A short review is given of the results of measurements with such equipment on a series of glasses. In partirular, experiments are described on the effect of (1) chilling, (2) prolonged heat treatment which produces an actual separation of phases, (3) mechanical strains, and (4) superposed radio‐frequency currents on the conductivity of the glass at room temperature. In conclusion, it is pointed out that the results of these measurements indicate that the electrical behavior of glass at room temperature is of importanc

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1933.tb16941.x

出版商:Blackwell Publishing Ltd    

年代:1933

数据来源: WILEY

摘要:

ABSTRACTViscosity data published by the author in 1931 are discussed with reference to their limitations. New experiments on fiber elongation in a redesigned apparatus are described in which one of the glasses previously used is tested. The results show that the viscosity of a newly drawn fiber increases with time of heat treatment according to a definite law which may be explained on the basis of a change in the state of aggregation in the glass. A finite equilibrium viscosity is indicated at each temperature, this limit being approachable from either side depending on previous heat treatment of the sample. This is taken to indicate an equilibrium average size of aggregate for any temperature, the groups starting to break up again if the temperature is increased after a long treatment. The expression of Sheppard and Houck is used for estimating effective molecular or aggregate weights in equilibrium at various temperatures, an example being 112,000 at about 500°C. The variation of viscosity with time is at least one reason why glasses fail to conform to Adams' and Williamson's annealing equation at low temperatures

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1933.tb16942.x

出版商:Blackwell Publishing Ltd    

年代:1933

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1933.tb16943.x

出版商:Blackwell Publishing Ltd    

年代:1933

数据来源: WILEY

摘要:

ABSTRACTIn spite of the lessened opportunity for moisture to pass the face of a terra cotta wall as compared with brick masonry, certain precautions should be observed to produce a water‐tight wall, especially where the exposure is severe. The bearing of each of the important properties of masonry cements in regard to their application to terra cotta is pointed out and recommendations are made for suitable cementing materials. Suggestions are offered for the selection of sand and for securing uniformity and intimacy of mix. A joint width of to ¼ inch is recommended where the regularity Of the units permits. The joints should be shoved and given a tool finish at the proper stage of stiffening. The joints subjected to extra severe exposure should be packed with prehydrated mortar and properly tool‐finished. Mortar may be aided to adhere to a glazed surface either by using prehydrated mortars or by first painting the surfaces with cement paint. For back‐up, a hollow tile with webs vertical is recom

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1933.tb16944.x

出版商:Blackwell Publishing Ltd    

年代:1933

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1933.tb16945.x

出版商:Blackwell Publishing Ltd    

年代:1933

数据来源: WILEY