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Volume 1992 (1992)
- Issue 241 Pages 425-
- Issue 240 Pages 291-
- Issue 239 Pages 225-
- Issue 238 Pages 135-
- Issue 237 Pages 72-
- Issue 236 Pages 3-
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Volume 1992, Issue 238
Displaying 1-11 of 11 articles from this issue
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Kenji SUGIMOTO, S. WIGNARAJAH1992 Volume 1992 Issue 238 Pages 135-144
Published: May 01, 1992
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSExperimental investigations were made to determine the influence of several factors such as temperature, strength, W/G ratio, section modulus, fiber reinforcement etc, on the deformation characteristics of gypsum board during early stages of aging.
It was found that increasing the section modulus or reducing the W/G ratio to be in the range 30% to 32% was effective in the controlling the deformation. It was also found that a decrease in the stress ratio increased the creep factor.
The deformation however, was not significantly affected by humidity or by the amount of glass-fiber added for reinforcement.
With the aid of these results, it was possible to determine the mixing proportion manufacturing conditions that would be effective in reducing the internal stresses and also in preventing the occurrence of cracks during the manufacture of the decorating gypsum board.View full abstractDownload PDF (1252K) -
Takao KITAMURA, Hideo WADA, Susumu OOIKE, Kenji AKIYAMA1992 Volume 1992 Issue 238 Pages 145-151
Published: May 01, 1992
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSThe effect of the addition of polyacrylic acid hydrazide (PAH) on mechanical strength and water resistivity of compact molded gypsum was studied. A small amount of PAH additive (0.3%) increased the bending strength and bulk density of both wet and dry specimens. Average bending and compressive strengths of wet samples prepared with the addition of 0.3% PAH and 20MPa molding pressure were 17MPa and 45MPa, respectively. However, PAH addition exceeding 0.5% decreased the bulk density and mechanical strength. Dissolution rate of gypsum into water was suppressed to 2/3 by PAH addition.View full abstractDownload PDF (1176K) -
Mitsuru UEDA, Takamichi IIDA, Hiroki ASADA, Kazuo WAKABAYASHI, Takashi ...1992 Volume 1992 Issue 238 Pages 152-158
Published: May 01, 1992
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSThe permeation of molten Cu and Ni into CaO compacts has been investigated by a button method, in order to make clear whether the CaO compacts can be used as a refractory for melting metals.
It was found that the metal concentrations in those compacts were a few per cent for nearly all samples of the compacts with a few exceptions. It was also observed that the metal concentrations could be kept low enough in the compacts formed under exactly controlled condition.
From the above results, it was found that the compacts can be used as practical refractories for melting metals.View full abstractDownload PDF (1041K) -
Tomohiko IIJIMA, Yoshiyuki OOMORI, Takashi OKU1992 Volume 1992 Issue 238 Pages 159-167
Published: May 01, 1992
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSSome properties of apatite cement which is composed of α-tricalcium phosphate and tetracalcium phosphate were investigated for use as a biomaterial.
The setting time and some physical properties were affected by the liquid/cement (L/C) ratio, but all of these results were suitable to be used for biomaterial.
The results of a fatigue test showed high dynamic strength (30Hz, 200kgf/cm2, 107 cycles). Exothermic temperature of the hydraulic hardening reaction was nearly human body temperature. In a liquid analysis, the concentration of Ca2+ was about 15 ppm and the pH elevation was over 10 at an early stage, but after that, pH fell down around neutrality in 3 days. Finally, the hydraulic hardened product had a porous body that was a good environment for new bone formation.
In animal experiments they showed the excellent new bone formation and high biocompatibility.View full abstractDownload PDF (1848K) -
1992 Volume 1992 Issue 238 Pages 167
Published: 1992
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSDownload PDF (169K) -
Kiyoshi ITATANI, Mamoru AIZAWA, Akira KISHIOKA, Makio KINOSHITA1992 Volume 1992 Issue 238 Pages 168-176
Published: May 01, 1992
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSPorous calcium phosphate film could be formed on a TiO2 substrate by a spray-pyrolysis technique. The aqueous solutions containing 1.0 mol· dm-3 Ca (NO3) 2 100 cm3, 0.6 mol· dm-3 (NH4) 2 HPO4 100 cm3 and conc. HNO3 6 cm3 were spray-pyrolysed at 600°C for 5, 10 and 15 h, respectively, to form calcium-phosphate layers on TiO2 substrate; TiO2 substrate coated with calcium-phosphate layers was heat-treated at a temperature between 1000°C and 1300°C. The calcium-phosphate film (thickness, -35 μm) containing pores with sizes of -50 μm was formed on TiO2 substrate under the following conditions : the spray-pyrolysis : 600°C and 10 h and the heat-treatment : 1250°C and 5 h. The calcium-phosphate film was bonded to TiO2 substrate through the reaction layers of CaTi4O9 and amorphous materials in the CaO-P2O5-TiO2 system. The surface layer of the film contained chiefly β-Ca3 (PO4) 2, whereas the bulk contained a-Ca3 (PO4) 2.View full abstractDownload PDF (2169K) -
Kazuaki HASHIMOTO, Yoshitomo TODA, Koshiro HASHIMOTO, Yasuo ARAI1992 Volume 1992 Issue 238 Pages 177-184
Published: May 01, 1992
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSThe formation of amorphous cobalt phosphate with color of blueish violet (Pe; 56.1%, Y; 9.4%, λd; 456.0 nm) was observed at the initial stage of the liquid reaction at 3°C in CoSO4-Na2 HPO4-H2O system, and the synthetic process of the precipitate, its thermal change and color change on heating were investigated.
The morphology of amorphous cobalt phosphate was spherical aggregate of fine particles with a diameter of ca.100 nm and specific surface area in the range of 50-70m2/g. Amorphous cobalt phosphate dehydrated gradually about 20 weight % in total with heating up to approximately 600°C, and crystallized to Co3 (PO4) 2 with heating at 645°C. It is concluded that the water molecules in amorphous cobalt phosphate is water of crystalline being similar to a free water without coordinated to Co2+ ion because its dehydration reaction begin at low temperature of about 40°C and no its color change by heating. The chemical formula was considered to CO3 (PO4) 2 · nH2O as a precursor of CO3 (PO4) 2 · 8H2O, from results of that amorphous cobalt phosphate changed to CO3 (PO4) 2·8H2O by suspending in mother liquer and its thermal change. The color of fine particles of Co3 (PO4) 2 obtained by heating amorphous cobalt phosphate in air at 800°C was blueish purple (Pe; 10.0%, Y; 18.2%, λc; 560.0nm) in color, though the color changed to deep purple (Pe; 15.8%, Y; 19.8%, λc; 555.1nm) by heating it in vapor steam.View full abstractDownload PDF (1314K) -
Yasuji HIMI1992 Volume 1992 Issue 238 Pages 185-193
Published: May 01, 1992
Released on J-STAGE: March 07, 2011
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Tamotsu YASUE, Yoshiyuki KOJIMA, Yasuo ARAI1992 Volume 1992 Issue 238 Pages 194-204
Published: May 01, 1992
Released on J-STAGE: March 07, 2011
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Naomichi HARA1992 Volume 1992 Issue 238 Pages 205-210
Published: May 01, 1992
Released on J-STAGE: March 07, 2011
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Motohide MATSUDA, Kimihiro YAMASHITA, Takao UMEGAKI1992 Volume 1992 Issue 238 Pages 211-215
Published: May 01, 1992
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSDownload PDF (704K)
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