By heating pieces of borosilicate glass (SiO₂ 81, B₂O₃ 12, Na₂O+K₂O 4.5, Al₂O₃ 2.5wt%) with surface stress caused by ultra-violet irradiation, stress relaxation process was observed. Results were as follows:
1. By heating up with the rate of 5°C/min, stress began to be released at about 250°C, faded away perfectly at 470°C, and did not reappear on cooling.
2. By soaking at 400°C, stress faded away perfectly in 30min. By soaking at temperatures between 250° and 360°C, stress decreased in initial periods of about 30min, and then attained at approximately constant values. The higher the soaking temperatures were, the less were these values, which did not change distinctly after cooling.
3. The temperatures described above were considerably lower than the annealing point (about 555°C) of the glass.
From these results, it was concluded that:
1. Stress is released by several mechanisms which participate in different temperature ranges.
2. Activation energies of relaxation mechanisms are presumed to be 35kcal/mol or smaller, and are considerably lower than that of viscous flow (about 100kcal/mol).
3. The stress relaxation is, therefore, presumed to be a result of, for example, reformation of deformed chemical bonds (bond angles, interatomic distances and so on) and not a result of rearrangement of network forming ions.
4. The same is possibly true for mechanisms of stress build-up.

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The mineral constitutions of zircon-dolomite refractories formed by the firing at 1500°C have been studied quantitatively by X-ray diffraction analysis. The materials consisted of zircon and zirconia in the range of 10-20mol% dolomite, and of calcium zirconate, periclase, tricalcium silicate, dicalcium silicate and merwinite in the range of 70-90mol% dolomite. In the other range of dolomite content, materials usable as refractories were not expected to be obtained because in the range of 30-70mol% dolomite, softening or melting occurred, and in the range of more than 90mol% dolomite, slaking occurred due to the free lime.
By considering systematically the order of all reactions that may occur, a method of calculation of mineral constitutions covering the ranges of 10-20mol% and 70-90mol% dolomite has been introduced. It was confirmed that the method gave very good agreement between experimental and calculated values in the former range, and considerably good in the latter range. It may be emphasized that this method of calculation is very useful not only for the fundamental study but also for the industrial application of the system.

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The various economic factors that should be considered in treating clay-bearing acid waste liquor and in designing its neutralization and recovery of usable by-product plant are discussed in detail.
Preliminary data are presented on the operation of a pilot plant operated by the Shôkôzan Kôgyôsho Company.

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Synthesis of titanium diboride was tried by carbon reduction method. The mixtures of titanium oxide, boron oxide and carbon black were inductively heated in graphite crucibles. The following reaction was expected.
TiO₂+B₂O₃+5C→TiB₂+5CO
Vaporization of boron and formation of titanium diboride were observed above 1500°C. The most suitable synthetic condition was to heat the mixture of TiO₂:B₂O₃:C=1:2:5 at temperatures above 1800°C.
Boron carbide was found in samples heated with excess boron oxide and carbon. Boron nitride was also found to be formed by gaseous phase reaction.

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