A series of experiments were carried out for investgating the factors having an effect on the color of chromium-containing glasses, expecting that the coloration would give a clue for elucidating the properties of the base glasses.
About 100 samples extending over silicate, borate and phosphate glasses containing chromium oxide, were melted in, respectively, oxidizing and reducing atmosphere. They were used for measuring spectroscopic transmission. Also the absorption at 280°-300°C of some specimens were measured in order to know the effect of temperature.
The change of the color of chromium-containing glasses may be attributed to two separate origins; one due to the equilibrium between Cr³⁺ and Cr⁶⁺, and the other due to the influence of electric field of 6O^2- coordinating Cr³⁺. The former may be explained by the atmosphare of glass melting and the basicity of base glass, and the latter in connection with the “single bond strength” of base glass, using the result obtained by the recent investigations of Bates and Douglas,
It is thus possible to give a semi-quantitative explanation of the blue color of the chromium-containing borate glass.
As far as the present experiments are concerned the change of the transmission curve by heating may be explained by the increase of Cr³⁺-O^2- distance. However, it is open to question whether this idea could be extended to the marked change of transmission at higher temperatures.

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Powdered frits of lithia containing glasses were added as the binding agent in a total amount of 5-20% to finely divided natural petalite (Li₂O⋅Al₂O₃⋅8SiO₂). The compositions of glasses were 4-18 Li₂O, 4-21 Al₂O₃, 52-86 SiO₂ and 5-25% (wt) (MgO+ZrO₂+P₂O₅). The mixtures were ball-milled to a finess smaller than 200 mesh, dry pressed under pressure of 900kg/cm² with an addition of 0.05% PVA, formed into bars of 5×5×50mm, and fired at a temperature 1080°-1320°C until the mixture sintered to an apparent porosity of about zero.
The results showed that the addition of the glasses produces profound effects in (a) increasing the firing range or the interval between the sintering temperature and the sagging temperature, (b) increasing the modulus of rupture of the sintered bodies, and (c) improving their thermal shock resistance.
Among the glasses tested the one having the composition, 10.7Li₂O, 8.9MgO, 8.9Al₂O₃, 71.5% (wt) SiO₂, showed the best results: The firing range was increased from-20°C for the body of 100% petalite ((-) means that the sagging temperature is lower than the sintering temperature and (+) the reversed case) to +40°C for the body containing 10 weight percent of the above glass. The strength of the sintered body was increased by 100%. The specimen of the above size withstood repeated quenchings from 1000°C into cold water without showing cracking or spalling.
In place of natural petalite, the other lithia containing minerals such as eucryptite (Li₂O⋅Al₂O₃⋅2SiO₂) and spodumen (Li₂O⋅Al₂O₃⋅4SiO₂) were used as the principal raw materials to be added with the lithia containing glass but without obtaining good results in regard to firing range and thermal shock resistance.

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The fluorescent X-ray analysis was successfully applied to determine the six major components in portland cement.
The measurements were carried on to determine the contents of Fe₂O₃, CaO, SO₃, SiO₂, Al₂O₃ and MgO, by a X-ray spectrograph with specially designed sample chamber, using ammonium dihydrogen phosphate (d=5.324 a. u.) as an analysing crystal, and in an atomosphere of hydrogen by means of gas-flow proportional counter and pulse height analyser.
Calibration curves were prepared from the commercial cements containing various amounts of above oxides.
In order to avoid the error caused by un uniformity of packing powder samples were pressed to the plates of the size 2cm×3cm under the pressure of 300kg/cm².
The determination of the components were made by comparing the intensities of FeK_αI, CaK_αII, SK_αI, SiK_αI AlK_αI, and MgK_α I of unknown to those of standard samples which were polished piece of Basalt, Calcite, Sulpher, and the plate of metallic magnesium.
The correction of the absorption effect of incident fluorescent X-ray was made taking into account of the mass absorption coefficient as well ss the geometrical characteristics of the apparatus.
Standard deviation of the analytical values obtained by the method given above with the calibration curves were 0.06% for Fe₂O₃, 0.14% for CaO, 0.11% for SO₃, 0.27% for SiO₂, 0.27% for Al₂O₃, and 0.16% for MgO.
Differences of the moduli obtained by fluorescent X-ray and chemical analysis were 0.03, 0.10, 0.08, 0.03 in silica modulus (SM), activity index (Al), iron modulus (IM), and hydraulic modulus (HM), respectively.
It has been proved that the complete determination of six major components given above can be carried out within about an hour, and that the proposed method may be applied as a rapid analysis for the quality control in the portland cement industry.

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From the standpoint of the utilization of the pottery stone of poor quality, the removal of iron content of Izumiyama pottery stone by the hydraulic cyclone was investigated.
According to the mineralogical study of Izumiyama pottery stone by N. Yoshida, our department, it is determined that the main mineral containing iron is pyrites. The specific gravity of pyrites is higher than those of quartz, sericite, kaolin which are the main mineral compositions of this pottery stone.
Therefore, it is preferable to use the hydraulic cyclone in order to remove the pyrites content.
The three samples of Izumiyama pottery stone of poor quality are provided by crushing with the ball mill during 6, 9 and 12 hours respectively.
The numerous experiments were carried out in order to clear up the relation between the operating conditions of hydraulic cyclone and the removing ratio of iron content.
The experimental results obtained are summarized as follows.
(1) The best operating conditions are as follows; the pulp density, 10%, feed pressure, 1.0 kg/cm², diameter of underflow nozzle (Du), 9.0mm.
The best results were obtained in the case of the sample crushed with the ball mill during 6 hours.
(2) The removing ratio of iron content in the best operating condition is 48%. In this case, the iron content of the feed sample is 0.729%; therefore, the iron content of the overflow sample is 0.729×0.48=0.35% Fe₂O₃.
The actual quantity of overflow sample is 48% of the total quantity of feed.

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Influence of gamma-irradiation upon properties of glasses have scarcely been studies excepting phenomena such as coloration and fluorescence caused by the irradiation. In this study, therefore, not only the influence of gamma-irradiation upon the electric conductivity of glasses, but applicability of glasses exposed by gamma-rays to semi-conductive glass or radiationdosimeter was studied.
The electric conductivity for ten kinds of glasses were measured after irradiating gamma-rays up to the maximum dosage of 10⁷r. using Co⁶⁰.
For the measurement of the electric conductivity, a vacuum tube voltmeter was used for the range of low resistance values and a vibration reed electrometer for the range of high resistance.
The result of the measurement showed that no change in electric conductivity of the glasses occured by the irradiation of 10⁷r. and consequently the gamma-irradiation to the glasses was found to be unapplicable in making semi-conductive glass and glass-dosimeter.

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