The properties of vermiculite mortar made of the vermiculite from Fukushima, Japan, were discussed. The following tests were carried out on the insulating mortar samples cured in damp air: thermal conductivity, bulk density, compressive strength, tensile strength and modulus of rupture. By means of hand mixing, the expanded vermiculite (temperature of firing: 600°C) and commercial portland cement were mixed until the resultant mass had a uniform color; water (mixed with the neutralized solution of vinsol resin) was then added, and the batch was mixed for about 5 min to have a unifom consistency. From the data presented, the following results were obtained: (a) The bulk density of mortar decreased as the vermiculite content increased. (b) The lower-density mortars had lower strength but higher insulation value. (c) The effect of vermiculite content on thermal conductivity was greater in the range of 1:1-4 than in the range of 1:4-9 (cement: vermiculite); the rate of decrease in the conductivity with the increase of vermiculite content changed abruptly at about 1:4 mixture. (d) The effect of vermiculite content on strength was greater in the range of 1:0-1 mixtures than in the range of 1:2-4 mixtures; the curve in the range between 1:0-1 was steeper than in the range between 1:2-4. (e) For general construction purposes except the most unusual load conditions, the best mortar can be produced with a 1:4 mixture in accordance with Scholes and his coworkers' results for N. Carolina vermiculite. The properties of this mixture (by use of 475 litres of H₂O per cu. m. of vemiculite and a mixing time of 5 min) after 28 days were as follows: Thermal conductivity, λ_t (kcal/m hr °C), at the mean temperature of t (°C): λ_t=0.0605+0.000191×t; bulk density: 0.902; compressive strength: 18kg/cm²; tensile strength: 7kg/cm²; modulus of rupture: 16kg/cm² (f) The vermiculite mortars produced with 1:8-9 mixtures had higher insulation values than the loose-filled vermiculite (expanded at firing temperature of 700°C) pressed by 20 per cent. (g) Data on thermal conductivity, bulk density and strength of vermiculite mortars having various ratios of cement: vermiculite were given. (h) Expanded “Fukushima vermiculite” would be excellent as an aggregate for light-weight mortar with high insulation value.

抄録全体を表示

Although transformation or stabilization of zirconia can be determined from its dilation curve, it was found that the electrical conductivity vs. temperature curve i.e., the change of the activation energy with temperature is one of the most sensitive properties for the phenomenon.

抄録全体を表示

Kalsilite (K₂O⋅Al₂O₃⋅2SiO₂) which was not known to crystallize out of the three-component melt of K₂O, Al₂O₃, and SiO₂, was found to crystallize from the system K₂O-Al₂O₃-SiO₂-B₂O₃-RO, wherein B₂O₃ and RO acted as the minerallizer for kalsilite. The crystallizing regions of kalsilite and of orthorhombic kaliophilite and the glassifying region in the system were investigated.
The results obtained were as follows:
a) Mixtures in the region richer in SiO₂ than K₂O⋅2SiO₂ and not so aluminoferous were usually glassified.
b) Orthorhombic kaliophilite was crystallized from the melt which is poorer in B₂O₃ than K₂O⋅Al₂O₃⋅2SiO₂⋅0.3B₂O₃, whether associated with RO or not.
c) In the system of K₂O⋅Al₂O₃⋅2SiO₂-B₂O₃ the mixtures in the region richer in B₂O₃ than K₂O⋅Al₂O₃⋅2SiO₂⋅0.4B₂O₃ were easily glassified, while addition of RO caused the glassified region to change into the crystallizing region of kalsilite.
d) The larger was the radius of R²⁺ ion, the more effectively it acted as minerallizer.

抄録全体を表示

In an emergency towards the end of the world war II, the Japanese Government planed the issue of stone ware coins. Private ceramic works in three major pottery districts of Japan were hired for the production. Raw materials of the each district were used, only the tint was adjusted between them by proper choice of iron containing material. Filterpressed cakes were disintegrated to pills and they were dried to 6-10% water. These semi-dry pills were fed into rotary tablet machines hitherto used for camphor preparations and stamped. Burning was done at cone SK 6-7 (abt. 1250°C) in tunnel kilns. The cions were made in the same diameters of the corresponding tin or aluminium coins but Somewhat thicker Thus in SETO factorv 13 millions and in KYOTO 2 millions of coins were made up to July of 1945. In ARITA factory step-up chambe kilns on hill side (“nobori-gama”) were used and few were made.
But before the coins became currency the war ceased and the entire of them was broken to the dust because the minimum necesary reserve of 25 millions of pieces was not atlained.

抄録全体を表示