What is termed “Shirasu perlite” in this report is a bloated glass particle from the Shirasu that is the volcanic ash and is located everywhere in the south of Kyushu. This ash has some interesting bloating characteristics, for instance, preheating treatment with following rapid heating may produce Shirasu perlite with closed-structure, while rapid heating with no preheating is apt to make the one with partly opened-structure.
Some results obtained to make the Shirasu perlite with closed-structure-type are summarised as follows;
1. The component of the gas to expand the Shirasu during bloating is considered as water from the results of the infrared spectra analysis and the gravimetric analysis.
2. Rapidly heated, the Shirasu begins to bloat at about 850°C and keeps on bloating to 1050°C. The temperatures to begin the bloating and softening of the ash which are closely related are also examined.
3. Shirasu has two peaks on the dehydration curve determined by T. B., one at about 300°-350°C and the other at 450°-500°C, while the perlite mineral has only one peak at 300°-350°C.
4. The higher the heating rate or the larger the particle size, the larger the shift to higher temperature of dehydration curve of the Shirasu. These characteristics of the Shirasu indicate that the heating rate should be correspondingly regulated to its particle size, in order to keep on water enough to expand the ash into sphere until getting to the bloating temperature.
According to these results, the continuous production of Shirasu perlite with closed-structure was satisfactorily performed using both a test and a commercial rotary kiln.

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高圧ガス圧縮装置を用いて, 温度1000°-1400℃, 圧力2kbarの条件下で酸化ベリリウムの静水圧焼結を行なった. この種の実験では, 従来, 圧力媒体として, 高融点金属が用いられてきたが, 著者らは, その代りにガラスを使用することにより, 非常に良好な結果を得た.
本実験において, その緻密化は, 塑性流動によって非常に速く進行するという結論が得られた. これらの焼結体は低い温度で, しかも比較的短時間内に, すべて理論密度の値に達しており, 粒子の異常成長は全く認められなかった. これらのことから, ガラスを圧力媒体とする静水圧焼結は, 均一な微粒子から成る緻密な焼結体が得られるものと結論できる. また, 焼結体の破断面の電子顕微鏡観察から, それは, 粒界に沿って破壊されていることが判明した.
粒成長の活性化エネルギーは, 75kcal/molの値が得られた. この値は, 従来報告されている値よりもやや小さいが, 体積拡散によって粒子の成長が進むものと結論できる.

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The heat contents of the alkali silicate glasses and crystals have been measured from 25°C to melting temperature with a continuous high-temperature calorimeter.
The entropy in the above temperature range is determined for the glasses and crystals of the composition R₂O⋅2SiO₂ (R=Li, Na, K). The free-energy change is calculated for the reaction of forming the glasses from the crystals. The free-energy values thus obtained are compared with those calculated from two approximate equations, ΔG=ΔT⋅ΔH_f/T_m and ΔG=(ΔT⋅ΔH_f/T_m)⋅(T/T_m). This comparison indicates that the free-energy values from these equations are inapplicable to the discussion on the kinetic process except for the case in the narrow temperature range near the melting point.
The relation between the heat capacity per mole of SiO₂ and composition expressed by the mole ratio R₂O/SiO₂ at 300° and 600°C is also investigated. In the system Na₂O-SiO₂ crystals, the heat capacity increases linearly with Na₂O/SiO₂ ratio. The slope of this straight line and the intersection at zero Na₂O composition approximately correspond to the heat capacity of crystalline Na₂O and that of crystalline SiO₂, respectively. From this result, it can be assumed that the additivity approximately holds for the heat capacity of Na₂O-SiO₂ crystals.
For Na₂O-SiO₂ and K₂O-SiO₂ glasses and supercooled liquids, the composition dependence of heat capacity shows an inflection at the composition of R₂O/SiO₂=0.5. These results are discussed from the view point of structure of glass and liquid.

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A method determining the radius of cylindrical specimens for measurements of thermal conductivity λ of solid materials by means of hot wire method was studied by investigations of relations between the radius γ of the specimen and the critical time T_d for the solid materials with various values of thermal conductivity. (T_d is a time where the relation between the temperature of the heat source θ and the time of log t deviates from a linear relation.)
The results were as follows:
1) Thermal conductivity λ, radius of specimen γ and critical time T_d were related experimentally with a formula T_d=γ²/10λ.
2) When T_d=300 sec, the radius of the specimen R suitable for the thermal conductivity measurement was expressed by a relation R=5√3λ/3 within an error of ±3%. From this relation, one can estimate the specimen radius R when an approximate value of λ is known.
For size effects of the specimen on a volume of the heating furnace at the thermal conductivity measurement at high temperatures, determination of the minimum radius of the specimen was one of the most important factors at the measurement.

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The density of water at kaolinite-water interface was estimated by measuring the volumetric change of a clay-organic system which occurred when clay-organic liquid interface was converted into clay-water interface. A definite amount of drops of water which had been previously introduced to the clay-water interface. A definite amount of drops of water which had been previously introduced to the clay-organic system was spread over the clay surface by stirring. The thickness of the layer of the abnormal water molecule on kaolinite was compared with that of pyrophyllite.
It was confirmed that the density of water from one to several molecular layers on kaolinite surface was less than that of ordinary water, indicating a looser structure. The density of the abnormal water was the lowest at the completion of coverage on kaolinite and amounted to a few percent less than that of ordinary water. The abnormal water was detected on pyrophyllite, but the thickness of it was shown to be smaller than that of kaolinite.

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Magnesia whiskers were grown by vapor phase reaction. The initial stage in the deposition of whiskers and their growth rates were examined. The results obtained were as follows:
1) Whiskers were not grown directly on the substrate surface, but powders deposited gave sites for whisker growth.
2) Epitaxially grown plateaus were observed on the substrate of magnesia single crystal.
3) The maximum leader growth rate of whisker was about fifty micron per second.

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This study was concerned with the characterization on the α-alumina-manganese solid solution, so-called manganese pink or tohshikoh. A mixture of aluminium hydroxide and manganese phosphate was calcined in air at 1250°C for 1h. The products were washed with (3:1) HCl to leach out all uncombined manganese compounds. Specimens were examined by X-ray diffraction technique for phase analysis and lattice parameter calculation, measurement of spectral reflectance, chemical analysis of manganese, and chemical state analysis of manganese by high resolution fluorescent X-ray analysis. In high resolution fluorescent X-ray analysis, chemical effects on MnK_β1.3 and MnK_α1 spectra were investigated. The width of MnK_α1 and the energy shift of MnK_β1.3 were found to be dependent on the chemical state, especially on the oxidation number of manganese. The changes in the MnK_α1 width and in the energy shift of MnK_β1.3 were large enough for the identification of the oxidation state of manganese in various compounds.
The results were summarized as follows.
1. X-ray diffraction patterns showed that the specimens consisted of only one phase, α-alumina. According to the chemical analysis, manganese content of these specimens ranged from 1 to 5%, and slight lattice expansion was observed.
2. Large difference in MnK_α1 width and the energy shift of MnK_β1.3 of products between before and after acid washing was observed. These values after washing corresponded to Mn³⁺. On the other hand, these values before washing showed the existence of Mn²⁺. From these observation, it was thought that crude specimens contained Mn²⁺ and small amount of Mn³⁺, and by acid washing, Mn²⁺ was eliminated and refined specimens contained only Mn³⁺. The color of specimens (manganese pink) could, therefore, be due to the incorporation of Mn³⁺ into corundum lattice.

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A sintering study was made on three kinds of alumina powders decomposed from aluminum sulfates. These sulfates are prepared from the solution of various concentration with varied precipitation rates. The effects of the precipitation rate on sintering were investigated and discussed with respect to the powder characteristics and the microstructures of green compacts and sintered bodies. Results are as follows;
The sample with rapid precipitation had a larger densification rate, especially in the initial stage of sintering than that with slow precipitation. The skeleton particle in the powder which is decomposed from the latter aluminum sulfate, is hardly broken down because of the large bond strength of the intra-particle. Those flat and unmovable skeleton particles possibly remain in the compact and they prevent the “rearrangement” which increases the densification rate in the initial sintering stage.

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Diffusion data of monovalent cations in glass have been analysed on the basis of several theoretical equations. Main results are as follows:
1. It was predicted that the following characteristics were applicable to the inter-diffusion data; (1) time-dependence of the depth of diffusion, (2) comparison of the diffusion profile with standard profiles derived by Fujita, and (3) linear relationship between the reciprocal of the inter-diffusion coefficient and the ion concentration. Many of the present data were, however, found not to satisfy the linearity (3).
2. Self-diffusion coefficient of Na⁺, D_Na*, derived from extrapolation of the curve (3), differs largely from the one, measured with isotope ²⁴Na. It is attributed to the difference of the field of diffusion in both cases, i.e., the D_Na* itself is a function of concentration. Temperature-dependence of D_Na* is larger than expected.
3. Partition coefficient of monovalent cation between the molten salt and the glass varies largely depending on the cation species. However, linear relationship is held between the reciprocals of the equilibrium concentrations of the distributed ion in both phases. Activity coefficients of the ions in glass can be approximately calculated from these equilibrium data and heat of mixing of molten salts in literatures.
4. Although the linearity (3) is somewhat improved by introducing these coefficients, the discrepancy is still large. The variations of ratio D_Na*/D_M* (M=K, Ag) are discussed on the basis of the irreversibility of the diffusion processes.

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The method for the direct determination of fluorine in glass on a solid by wide-line NMR (60 MHz) is studied.
The results are summerized as follows.
1) As the water content of a powdered sample was increased, intensity of fluorine resonance decreased.
2) As the amounts of paramagnetic impurities increased, intensity of fluorine NMR signal increased enormously and the plateau regions were in the range more than 0.06% for Fe₂O₃.
3) R. F. saturation factor and spectral line width of ¹⁹F signal on fluoride system differed with glasses.
This spectroscopic method can be applied to routine analysis when amounts of other components of glasses do not vary.

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Silas balloon-carbon composite material was prepared from silas balloon and pitch binder mixture, where the pitches used were coal-tar pitches and asphalt pitches. The best conditions for production of this composite material were determined from the measurement of bulk density and compressive strength of silas balloon-carbon composite material prepared under various condition. The heat-resistance and the resistivity against chemical reagents of this composite material were measured, and the microstructure of this composite material was observed by a optical microscope.
From these results, the properties of silas balloon-carbon composite material obtained are following, that is, bulk density is 0.8-0.85g/cm³, compressive strength is 290-300kg/cm², bending strength is 140-150kg/cm², heat-resistance is 400°-500°C in the atmosphere of oxidizing gas and 1150°C in the atmosphere of non-oxidizing gas.

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The Shigaraki district, south of lake Biwa, is located at the southern part of Shiga prefecture. ‘Shigaraki’ is well-known as one of the six old kilns in Japan, where has a history since about 1, 200 years ago. The present writers have carried out geological field survey and mineralogical study of the clays by using the technique of X-ray diffraction, electron-microscope and thermo-analysis.
The lower part of the Pliocene sediments in the Shigaraki district, lower stratum of Paleo-Biwa group, is abundant in the commercial clays such as ‘gaerome’ clay, ‘kibushi’ clay and white clay (Shirae). They are considered as sediments in the present Shigaraki plateau in the northern part of the Iga tectonic basin. The irregularity of clay deposits and the variation of quality as raw clay material in the three sections of Sangoyama-Makiyama, Hosohara-Nakazato-Shimode and Kumoi were able to be considerably explained by the geological full survey.

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