In order to investigate the effects of drying or heating on the surface properties of clay minerals against water, heat-of-wetting in water was measured for clays of montmorillonite and kaolinite types. Before the measurement, cations on the surface of the original clay particles were exchanged for Ca²⁺, Mg²⁺, H⁺, Na⁺, or K⁺ ions, and the clay particles adsorbing these cations were dried or heated at various temperatures up to several hundreds degrees.
The results obtained are summarized as follows:
1) The heat-of-wetting of clay minerals is greatly affected by the condition of drying or heating pretreatment.
2) As has already been recognized by many authors, the heat-of-wetting of clays is closely correlated with the type of cation adsorbed on their surface. Because of the other complicated factors involved, however, the heat-of-hydration of cations adsorbed is unable to estimate quantitatively from the measured value of the heat-of-wetting of clay.
3) The estimation of the hydration character of the original clay surface from heat-of-wetting value is rather absurd than unable, because the preheating of the clay sample which is a necessary procedure for the measurement of heat-of-wetting greatly changes the original state of the clay surface by fixing adsorbed cations on its surface.
Some critical discussions were made on the published works carried out so far on the same subject by many authors.

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Radioisotope techniques were used for the study of the corrosion resistance of the four kinds of sintered dunite refractory materials.
The crushed powder of electrically fused dunite (see Table 1) were mixed with or without dolomite, limestone, or magnesia clinker (see Table 2 and 4), shaped into a crucible-like form by pressing, sintered at SK 27-32. The steel-making lime slag added with a small amount of R. I. ⁴⁵Ca in the form of ⁴⁵Ca(NO₃)₂ was melted in the crucible at 1610°C for about 1 hr. The penetration of ⁴⁵Ca into the inner fine structure of the crucible was examined by autoradiography.
The results obtained were as follows:
1) Autoradiography has given an informative picture of the actual penetration of the slag into the fine structure of refractories, with good resolution, which is unobtainable with an ordinary microscope.
2) The penetration of ⁴⁵Ca has been found to be fairly slight for the refractory material added with magnesia clinker, while extremely deep for those added with lime stone or dolomite, compared with for the material consisting of only fused dunite.

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An experimental investigation of sintering process of nickel-bonded titanium cardides was carried out by means of dilatometric and metallographic methods.
Powders of titanium carbide and nickel were ball-milled in addition with methyl alcohol for 25 hours. The average diameters of the particles after ball-milling were 2.5 microns for titanium carbide and 3 microns for nickel, respectively. Powders of seven compositions; 10, 20, 30, 40, 50 and 75 per cent nickel by weight, and titanium carbide only (100 per-cent TiC), were pressed in a graphite mold at 50kg/cm². The linear shrinkage, during sintering, of the compacted of each powder in the graphite mold was measured in argon atomosphere with a silicon carbide dilatometer. The temperature was raised linearly at the rate of 250°C/hr up to 1500°C and kept there for 1 hour and then cooled linearly at the rate of 250°C/hr. For all compositions except the one of 75 per cent nickel, the shrinkage was slight up to 1200°C, but increased abruptly in the range 1200° to 1350°C. This abrupt shrinkage was attributed to an appearence of liquid phase in the sample. With increase of nickel content, the total shrinkage during sintering increased but the temperature at which the abrupt change begins dropped. Change in linear shrinkage during kept at 1500°C was proportional to logarithm of the sintering time.
After the measurement of shrinkage, the sintered compacts were subjected to the metallographic examination. It was confirmed that the shape of carbide particles changed from spheroid to polygone with increased nickel content. The particle size and the “sphericity index” of carbide, however, did not change so much with the composition. The change in shape of the particles in the nickel-bonded titanium carbides may be attributed to the continuity of liquid phase appeared during sintering.

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The purpose of this investigation is to study the effects of various impurities which might be present in sea-water magnesia on the sintering and dead-burning properties.
The influence of CaO, SiO₂, Al₂O₃, Fe₂O₃ etc. additions on the sintering and dead-burning of magnesia has been investigated. The results obtained are shown as follows;
(1) The sintering of dead-burned magnesia is influenced greatly by molar ratio of CaO/SiO₂ and CaO/Fe₂O₃, (2) and the suggestion is made that the effect of additions in promoting the sintering of sea-water magnesia may be related to the chemical composition of the original sea-water magnesia.
(3) The relation between the sintering characteristics of magnesia and molar ratio CaO/SiO₂, CaO/Fe₂O₃, and CaO/Al₂O₃ was made clear.
(4) There is no obvious relationship between the densification of dead-burned magnesia and the promoting growth of periclase crystals.
(5) An optimum addition of additives beyond which sintering is inhibited was determined from the study of mineral composition of products.

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Sulpho-aluminous cement, explained by H. Lafuma, is produced by burning the mixtures of gypsum, bauxite and lime. It is used as expansive agent for making expansive cement. For the constituents of Sulpho-aluminous cement (or clinker) Lafuma described that the free CaSO₄, γ C₂S are found but the presence of calcium sulpho-alminate is not confirmed. In the studies of calcium sulpho-aluminate admixtures for expansive cement Klein indicated the presence of ternary compound, calcium sulpho-aluminate, in sulpho-aluminous clinkers, though this compound was not identified.
In this paper the compound compositions of the following specimens were determined. Phases were identified by X-ray diffraction. Specimens were (1) ordinary sulpho-aluminous clinker obtained from mixture of gypsum, bauxite and lime, (2) special samples prepared by burning the mixtures of commercial alumina cement and gypsum, (3) clinkers prepared by varying molar ratio Al₂O₃/SO₃ of above clinkers.
The data indicated that the ternary compound, 3CaO⋅3Al₂O₃⋅CaSO₄ was a most abundant constituent of the clinkers. For the other constituents free CaSO₄ was found distinctly but C₂S rather uncertainly. The calculation of compound compositions of the sulpho-aluminous cements was also tried.

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