The thermal fracture of roofing tiles during cooling in tunnel kiln was studied by means of the photothermoelastic technique.
The models of roofing tiles were made of epoxy resin plates. The isochromatic photographs of the fringe patterns showed the stress concentrations in the parts of notches and nail holes.
For the purpose of decrease of stress concentration, some suggestions regarding the shape of notch and the position of nail hole were obtained. So as to avoid the thermal fracture, wide space setting of roofing tiles on the kiln-car is more effective than modification of cooling schedules.
The temperature differences causing failure for the monotonous plate were theoretically estimated at from 160° to 170°C.

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In order to study nature of BeO powders, calcined at various temperatures, we have measured the heats of wetting (ΔHi) at 25°C in water. They were produced from sulfate and hydroxide. The BeO powders produced from sulfate and calcined at 900°C was named S₉₀₀BeO and that produced from hydroxide and calcined at 800°C, H₈₀₀BeO and so on.
1) ΔHi of S₁₁₀₀BeO and S₁₂₀₀BeO increases monotonously as outgassing temperature is raised, but ΔHi of S₉₀₀BeO, S₁₀₀₀BeO, H₈₀₀BeO and H₁₀₀₀BeO reaches maximum at outgassing temperature of 800°C ΔHi of H₁₂₀₀BeO and H₁₃₀₀BeO outgassed at 800°C is nearly equal to that outgassed at 1000°C.
2) ΔHi of the BeO powders produced from hydroxide is larger than that from sulfate in the region of this study but outgassed above 800°C.
3) ΔHi of the BeO powders made from sulfate differs one another with calcination temperature. Above outgassing temperature of 600°C, ΔHi of the BeO powders increases as calcination temperature is raised. ΔHi of H₁₀₀₀BeO is the largest among those of the BeO powders produced from hydroxide but the differences in ΔHi among them are small.

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An experiment of application of the ion probe mass analyzer, the newest instrument for characterization, was carried out through the observation of material transport in case of the solid state reaction.
The self-diffusion phenomenon which can not be observed by EPMA could be observed using an isotope as a tracer. The local resolution which can not become less than 5μ in case of applying EPMA to light elements was about 10μ in to-day's condition, but it is theoretically expected to become less than 0.5μ. An obstacle of charging-up in case of applying to inslators was settled by using an electron spray. The quantitatire determination of concentration was remained as a future problem.

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The fiber elongation method is possible to measure the viscosity of glass over a range from 10⁸ to 10¹⁵ poises. But it is not easy to measure the viscosity of non-oxide glasses such as chalcogenide glasses, since the preparation of samples needs the forming by heating.
The viscosity of non-oxide glass as well as oxide glass are measured over a range from 10¹⁰ to 10¹³ poises, using a thermodilatometer shown in Fig. 1. In a practical experiment soda-lime-silica glass, NBS 710, of which temperature-viscosity characteristic is known, has been used as oxide glass, and chalcogenide glass, arsenic triselenide synthesized by authors has been done as non-oxide glass. These samples are of pillar shape (3×3×20mm). Instantaneously exerting compressive stress caused by applied load (20 or 50g) on the sample, strain-time curves shown in Fig. 2 or 3 are obtained. These experimental results can be explained well by rheological 4-elements model shown in Fig. 4 in the same manner as the fiber elongation. Therefor the viscosity of glass at constant temperature is obtained by following equation, η=mg/S(-Δl/l₀)/Δt, where η is the viscosity of glass (poise); mg, the applied load (dyne); S, the sectional area of sample; and (-Δl/l₀)/Δt, a tangent of the linear part of curves in Fig. 2 or 3. Measured viscosity values of NBS 710 are given in Table 1. These results show that the viscosity obtained by the fiber elongation method is normal viscosity, while the viscosity by this compressive method is shear viscosity.

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Calcium metaphosphate glass was prepared by melting an appropriate amount of the mixture of orthophosphoric acid and calcium carbonate in a Pt-crucible at 1250°-1300°C. The composition of the glass was determined as CaO 48.0, P₂O₅ 49.1 and H₂O 2.9 in mol% by chemical analysis and transformation temperature of the glass was 512°C.
For elucidation of crystallization kinetics of the glass at temperatures under ca. 800°C, the crystal growth rate in the blown film sample and the amount of crystal formed in the powdered sample in size from 44 to 74μ were measured by means of high temperature microscopy and high temperature X-ray diffraction techniques.
1) The induction periods of crystallization were determined from the isothermal crystallization curves. From Arrhenius plots of the induction periods, the activation energy of nucleation of β-calcium metaphosphate was calculated to be 115kcal/mol.
2) The activation energies obtained for the crystal growth and the crystallization of β-calcium metaphosphate were 110 and 118kcal/mol, respectively, being essentially identical with the activation energy of nucleation of this crystal.
3) By applying the J-M-A equation to the data obtained it was shown that the crystallization of β-calcium metaphosphate contained the following processes, the thermal nucleation and the three-dimensional growth.
4) The activation energy of nucleation of γ-calcium metaphosphate formed metastably in the initial stage of crystallization of the glass was estimated to be larger than that of β-calcium metaphosphate.

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The densification rate of aluminum nitride under 200kg/cm² pressure and at a constant rate of heating was examined through the linear shrinkage measurement. AlN containing 0.2-1.0 wt% of iron was densified slower than iron free AlN, when the heating rate of the temperature between 1550°-1800°C was rather slow, 5°C/min for example.
The crystal growth by Vapor-Liquid-Solid mechanisum was observed in the case of AlN where the liquid phase was a melt of iron. The recrystallized crystals among small particles of AlN prevent the densification and build up porous construction. The slow-down of the densification rate above mentioned is thought to be caused by the dissolution and precipitation of AlN through the melt of iron.
This delay of densification was remarkable at a slower rate of heating, and on quick heating such as 350°C/min, there was no delay of densification, but the densification rate was somewhat accelerated by addition of iron.
To make dense sintered bodies, the result of this experiments showed that AlN containing 0.2-1 wt% of iron impurity must be heated up to 1800°C rather in short time interval.

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The effects of substitution of Na₂S to Na₂O on the physical properties, such as the density, elastic moduli and thermal expansivity, of germanate glasses in the systems Na₂OGeO₂ and Na₂S-GeO₂ were studied in order to clarify the behavior of sulphur introduced in large quantities into glass structure. The density of the glasses was determined by Archmedes method with a sensitive microbalance and kerosene. The elastic moduli were calculated from the sound velocities of the glasses measured by a pulse superposition method. The thermal expansivity was determined by using a dilatometer and the transformation temperature was obtained from the thermal expansion curve. The results are summarized as follows:
The density and bulk modulus of the glasses in both systems increase with increasing alkali content at first, but start to decrease when alkali content becomes more than 17-18mol% in Na₂O-GeO₂ glasses and 6-7mol% in Na₂S-GeO₂ glasses. The density and bulk modulus of a glass containing Na₂S are considerably lower than those of a glass containing Na₂O when both glasses have the same alkali content. The glasses with Na₂S have higher thermal expansivity and lower transition temperature than those with Na₂O.
The increase in molar volume of these glasses, resulting from the substitution of S to O, was calculated from the density and composition of glasses and compared with the value calculated from the difference in ionic radius or covalent bond length between O and S.

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Kaolinite was formed from fluorphlogopite through hydrothermal reaction with AlCl₃ solutions of various concentrations, within the range of 200°-450°C. I-R spectrum, DTA curve, X-ray diffraction pattern, etc. of the product show that it corresponds to natural b-axis disordered kaolinite. There is no evidence that the kaolinite contains fluorine as its characteristic anion. The presence of structural relationship between the starting material and the kaolinite was proved by the formation of oriented aggregates of the kaolinite pseudomorph after fluorphlogopite.
Mechanism of the reaction is discussed from crystallographic aspects.

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組成に依存する空位を含むイオン結晶固溶体に関して, 近似的な熱力学的取扱いを試みた. その際, サイト数の関係だけでなく, 電気的中性の条件もみたされるように考慮したところ, 化学ポテンシャルに関する簡単な式が, 空位濃度を含んだ形で導き出された. この式を, 固溶体の蒸気圧, 遷移金属酸化物系の平衡酸素分圧, および空位濃度勾配を含む固溶体中の陽イオンの相互拡散に適用した結果, 既に報告されている多くの実験値の組成依存性を説明することができた.

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熱容量が非常に小さい小型の加熱炉をつくり, これを通常の偏光顕微鏡に取りつけた. この高温顕微鏡を用いて, Li₂O・2SiO₂および33.3Li₂O・66.7SiO₂・1.5R₂O(R; Na, K, Cs) ガラス中に析出する結晶の成長速度を測定した. Li₂O・2SiO₂ガラス中には, リチウム・2珪酸塩結晶のみが析出した. 成長速度の測定値および結晶成長理論より, この結晶は螺旋転位機構によって成長することが推察された. また, 結晶-融液界面における拡散の活性化エネルギーは, 融液の粘性の活性化エネルギーに等しいことを確めた. 33.3Li₂O・66.7SiO₂・1.5R₂Oガラスからは, リチウム・2珪酸塩結晶とともにリチウム・メタ珪酸塩結晶も析出した.

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The solid state reactions of dickite and pyrophyllite with CaO at 900°C were investigated paying attention to the direction of diffusion, the preference of reactivity of the two minerals, and to the difference in the reactivity between edge and basal crystal surfaces.
Pt-marker method was used for examining the direction of diffusion. The amount of CaO reacted was determined by glycerin-ethanol method.
The conclusions obtained are as follows.
1. CaO preferentially diffuses into the clay minerals.
2. Pyrophyllite is more reactive with CaO than dickite.
3. Edge surfaces of dickite is much more reactive than basal surfaces.
4. Pyrophyllite shows no noticeable difference in the reactivity with CaO between the two crystal surfaces as of dickite.

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The absorption spectra of three photochromic glasses containing silver halide crystals were measured at liquid nitrogen temperature. Followings were noted as interesting feature. (1) The absorption band at around 360nm was commonly observed in three glasses. (2) In the glasses showing moderately rapid fading, the large absorption band was observed at around 650-750nm but similar band was not found in the glass showing extremely slow fading. (3) In a glass, an absorption band was clearly observed at around 500nm.

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