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Volume 1990, Issue 224
Displaying 1-8 of 8 articles from this issue
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Kiyoshi ASAGA, Younshik CHUNG, Takaaki TSURUMI, Masaki DAIMON1990 Volume 1990 Issue 224 Pages 3-8
Published: January 01, 1990
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSAuthors proposed the analytical method for vibrational viscometry to determine the rheological properties of non-Newtonian suspension systems. Experiments were performed on five kinds of slag powder with different particle shapes and particle size distributions. Following results were obtained,
1) The shear stress and shear rate were calculated from the applied force and the amplitude of vibration of the measuring plates. Rheological properties of non-Newtonian liquid could be discussed by using the relationship between the shear stress and shear rate.
2) Since the fine slag powder produced via classification process had angular particles and a very narrow distribution of particle size, the dilatantic behavior was clearly observed in the rheological properties of the paste.
3) The grinding of the fine slag powder broadened the particle size distribution and changed the particle shape to more spherical. Such changes in particle characteristics decreased the viscosity and weakened the dilatantic behavior of the paste.View full abstractDownload PDF (973K) -
Tamotsu YASUE, Atushi KIDERA, Yasuo ARAI1990 Volume 1990 Issue 224 Pages 9-14
Published: January 01, 1990
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSThe dissolution of insoluble silicates in aqueous suspension containing strongly acidic ion exchange resin (H-R) has attracted as application for special dissolution method. In order to clarify the suitable conditions on dissolution of β-C2S (β-Ca2SiO4, ortho-silicate), the conditions such as amounts of H-R and water, time, temperature on dissolution of β-C2S were studied mainly by means of pH, specific conductivity, chemical analysis and trimethylsilylation (TMS) method in dissolved solution prepared in this paper.
The dissolution of β-C2S was made by stirring the suspension containing mixture of β-C2S and H-R in water. Under such conditions of β-C2S with 0.5g, water with 100 cm3, time for 30 min and temperature at 20°C, the dissolution of silicon in β-C2S increased gradually in proportion to amount of H-R, but its value as S-Si/T-Si % hardly reached in equilibrium state at 55 % and calcium in β-C2S exchanged completely in the case of H-R above 5g. The finding was due to reform silica gel as result of polymerization of the dissolved once silicate anions from β-C2S. Also the dissolution rate accelerated to 95 % by increasing amount of water to 1000 cm3 from 100 cm3. Amount of SiO44- ion in the dissolved silicate anions was 95 %, while was 65 % as ordinary dissolution method in HCl. In comparison with ordinary TMS method using HCl, this method using H-R should be a useful technic for dissolution of β-C2S.View full abstractDownload PDF (769K) -
Takashi SUZUKI, Toshiaki HATSUSHIKA1990 Volume 1990 Issue 224 Pages 15-20
Published: January 01, 1990
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSLattice ion reaction characteristics between Ca2+ ions of synthetic hydroxyapatite (HAp) samples and Fe2+, Fe3+ ions in acidic aqueous solutions (pH : 2.0-5.0) have been investigated in detail by a normal batch method at 25°C. It was found that Fe2+ ions are slightly exchanged with Ca2+ ions of the HAp samples over pH of 4.0 but under pH of 4.0, dissolved reactions of HAp with H+ ions become dominant instead of the exchange reaction. Removal behavior of Fe3+ ions, however, was found to be quite different from that of Fe2+ ions, i.e., Fe3+ ions are easily removed, assisted by the loosening effect of H+ ions on the skeletal structure of the HAp samples, and the HAp samples are transformed into stable amorphous products (FePO4·mH2O) even in acidic solutions with low pH of 3.0 or below. Moreover, coexisting systems of Fe3+ and Pb2+ ions, with which HAp samples have been found to be easily converted into crystalline stable lead apatite in acidic solution, have been investigated under the conditions of low pH values (pH : 2.3-5.2). An interesting effect was found that the two ions suppress each other the reactions of the ions with HAp samples. These results are important in discussion concerned with reaction characteristics between human bones and teeth, whose main constituent is HAp, and invaded Fe2+, Fe3+ and Pb2+ ions into human bodies.View full abstractDownload PDF (623K) -
N.B. Singh, S.P. Pandey1990 Volume 1990 Issue 224 Pages 21-25
Published: January 01, 1990
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSHydration studies of commercial plaster of paris in presence of citric acid have been made by using temperature and electrical conductivity measurements. X-ray diffraction studies, Differential Scanning Calorimetry, Spectral studies and Compressive Strength measurements have also been made to understand the mechanism of hydration. Results show that citric acid retards the hydration. It is proposed that citric acid in the form of citrate ions are adsorbed on the plaster surfaces and retards the hydration.View full abstractDownload PDF (560K) -
Shigeki AOKI, Yasuo ARAI1990 Volume 1990 Issue 224 Pages 26-31
Published: January 01, 1990
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSDownload PDF (791K) -
Motohiko YOSHIZUMI1990 Volume 1990 Issue 224 Pages 32-38
Published: January 01, 1990
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSDownload PDF (1376K) -
Hiroshi FUKUYO1990 Volume 1990 Issue 224 Pages 39-46
Published: January 01, 1990
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSDownload PDF (1573K) -
Kohei INO1990 Volume 1990 Issue 224 Pages 47-50
Published: January 01, 1990
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSDownload PDF (682K)
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