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| 1.
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土成, 昭弘 ; 保木井, 利之 ; 下林, 修 ; 金岡, 千嘉男
概要:
In a permeable MgO ceramic containing TiO_2 and Al_2O_3 as matrix MgO ・ Al_2O_3-2MgO・TiO_2 solid solutions were detected
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and no Al_2O_3・TiO_2 was observed. Therefore, the solid state reaction among MgO, TiO_2 and Al_2O_3 with excess MgO was studied at various firing temperatures. The formation mechanism of MgO・Al_2O_3-2MgO・TiO_2 solid solutions was studied from the results of interface reactions between MgO-TiO_2 and MgO-Al_2O_3. MgO・Al_2O_3-2MgO・TiO_2 solid solutions were detected at 1573-1673 K and increased with the firing temperature. 2MgO・TiO_2 was formed in the system MgO-TiO_2, but was not produced in the system MgO-TiO_2-Al_2O_3, because the amount of Mg diffusion at the interface of aggregate and matrix additives was not enough due to the large aggregate size of MgO. MgO・Al_2O_3 and 2MgO・TiO_2 formed at the interface between MgO-TiO_2 and MgO-Al_2O_3 decreased with the firing time at 1873 K. On the other hand, MgO・Al_2O_3-2MgO・TiO_2 solid solutions increased. Mg was recognized in the matrix without addition of MgO as a matrix. Al diffused in the layer of MgO-TiO_2, in opposition Ti diffused in the layer of MgO-Al_2O_3 by EPMA analysis. From the above results, the formation mechanism of a MgO・Al_2O_3-2MgO・TiO_2 solid solution was proposed; (1) Mg diffusion at the interface of MgO aggregate and matrix additives, (2) formation of MgO・TiO_2 and MgO・Al_2O_3, (3) formation of 2MgO・TiO_2 due to the reaction with MgO・TiO_2 and MgO, (4) reaction of the solid solution with MgO・Al_2O_3 and 2MgO・TiO_2. In the reactions between MgO・TiO2 and MgO-Al_2O_3 the product layer of MgO・Al_2O_3-2MgO・TiO_2 solid solution increased as the firing time increased. The diffusion coefficient of Mg was about 4.8×10^<-7>(cm^2/s), in a good agreement with that of Mg which was reported.
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| 2.
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土成, 昭弘 ; 保木井, 利之 ; 下林, 修 ; 金岡, 千嘉男
概要:
Changes in the structure and physical properties of porous magnesia ceramic containing TiO_2-Al_2O_3 matrix with TiO_2-Al_2O_3 molar ratio 0.96 and 15 wt% content were studied at different sizes and firing temperatures for controlling
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the pore shape. The shape of pore was complicated depending on the grain size and firing temperature, and pores were found to have a fractal nature. While the fractal dimension increased with increasing firing temperature for small grains, it decreased with increasing firing temperature for large grains. The fractal dimension of each MgO grain size tends to converge at a lower firing temperature which is close to the temperature at which the MgAl_2O_4-Mg_2 TiO_4 solid solution is formed. Specimens with small grains were found to shrink on firing, but the expansion was observed for large grained specimens. These phenomena were explained by the densification and molar volume of MgAl_2O_4-Mg_2TiO_4 solid solution and CaTiO_3 formed. From the above facts, it was possible to controll the pore shape by grain size and firing temperature.
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| 3.
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土成, 昭弘 ; 保木井, 利之 ; 下林, 修 ; 金岡, 千嘉男
概要:
Changes in the structure and permeability of porous magnesia ceramic with a TiO_2-Al_2O_3 matrix with a TiO_21Al_2O_3 molar ratio of 0.96 were studied at different matrix contents. The shape of pores became complicated and pores
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tended to have fractal nature as the matrix content increased. It was proposed that the change of pore shape was caused by the increase in the amount of the matrix and its reaction with MgO grains. Both mean pore diameter and permeability showed a maximum at a matrix content, 10 wt% and 15%, respectively. On the other hand, the fractal dimension of pore shape changed from 1.39 at 5 wt% to 1.65 at 20 wt% of matrix. The fractal dimension changed sharply between 10-15 wt%. The permeability was found to agree well with that of a nonspherical particle system by using pore size modified by the its fractal dimension.
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| 4.
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土成, 昭弘 ; 保木井, 利之 ; 平木, 外二 ; 金岡, 千嘉男
概要:
Properties of permeable magnesia refractory containing titania and alumina powder in the matrix were investigated in order to produce permeable refractory with high thermal shock resistance, corrosion resistance and low penetration of
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molten steel. By adding titania and alumina powder in the matrix, bright glossy portion and dark glossy portion were observed in the matrix and in the grain boundary of magnesia. Bright glossy portion was CaTiO_3 (Perovskite) from X-ray diffraction and EPMA analyses. Dark glossy portion was suspected to be Al_2TiO_5 (Aluminum Titanate) from EPMA analyses although Al_2TiO_5 was not detected by X-ray diffraction. The collapse of magnesia grains was caused by the generation of CaTiO_3 and Al_2TiO_5 in the magnesia grain boundary. Apparent porosity, mean; pore diameter and permeability became high and large as TiO_2/Al_2O_3 molar ratio decreased, and reached the maximum value at the equivalent molar ratio. However, above the equivalent molar ratio the values became low and small. Permeability was proportional to the product of apparent porosity and the square of average pore diameter. Thermal shock resistance increased twice compared with no addition of TiO_2/Al_2O_3. Although corrosion resistance deteriorated by adding TiO_2/Al_2O_3, it was superior to the conventional porous alumina refractory. Penetration thickness of molten steel was not dependent on TiO_2/Al_2O_3 addition, and was very small compared with conventional one. This permeable magnesia refractory will have a good possibility of being used on actual operation.
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金岡, 千嘉男 ; 古内, 正美 ; 畑, 光彦 ; 坂野, 健夫 ; 川南, 吉弘
概要:
金沢大学自然計測応用研究センター<br />金沢大学工学部<br />金沢大学大学院自然科学研究科環境基盤工学専攻
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金岡, 千嘉男 ; 古内, 正美 ; 畑, 光彦 ; 坂野, 健夫 ; 川南, 吉弘
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金岡, 千嘉男 ; 古内, 正美 ; 畑, 光彦 ; 岡部, 孝往
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金岡, 千嘉男
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| 9.
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金岡, 千嘉男
概要:
大東文化大学環境創造学部<br />金沢大学21世紀COEプログラム 環日本海域の環境計測と長期･短期変動予測－モニタリングネットワークの構築と人為的影響の評価－
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金岡, 千嘉男 ; Kanaoka, Chikao
概要:
金沢大学自然科学研究科<br />本研究では,快適性を向上するための制御手法を開発するために,主要な因子であるVOC,粉塵,気流について実験と理論解析により検討し,以下の研究を行った。平成10年度1)VOCの揮散および存在形態と挙動の解明1
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.1 建材表面からのVOCの揮散機構を測定するための実験方法を確立し、温度と成分によって揮散物質の濃度変化の傾向が異なっていることを明らかにした。2)粒子状物質の発塵機構と室内での挙動の解明2.1 床面からの粉塵捲き上げ量を測定し、床材により発生量が異なり、また運動量の増加に伴い発生量が増加することを明らかにした。さらに、粉塵捲き上げモデルにより粉塵発生率の推定を行った。3)居住空間内気流の解析3.1 発熱・発じんを伴う空間のレイヤーベンチレーションに関する基礎的検討熱源を持つ空間内の流れの可視化実験及び、数値計算を行い、空間内の中層域以下に循環流を発生させるレイヤーベンチレーションは、浮力の影響が強い空間での換気に適していることを確かめた。3.2 気流及び燃焼排ガス濃度分布の数値解析換気方式が異なる居住空間内の空気環境の数値解析を行い、給気方式による室内換気の有効性を明かにした。平成11年度4)快適性向上技術の開発4.1 ナノサイズTiO_2粒子を担持したPTFEシートによるVOC除去ナノサイズTiO_2粒子を担持したテフロン製網状シートに紫外線照射してTiO_2粒子表面上にVOCを吸着・酸化させることによりVOCが除去されることを確かめた。4.2 ナノサイズTiO_2エアロゾルによる有害物質除去に関する基礎的検討VOCなどの気中有害物質の除去を効率的に行う方法として、ナノサイズTiO_2エアロゾル粒子に紫外線照射・活性化する方法に検討を加え、TiO_2粒子表面上に有害物質を効果的に吸着・酸化させて除去できるのを確認した。またSiO_2の添加がTiO_2の活性化を抑制することがわかった。<br />19981) Transport mechanism and distribution of VOC inside constructing wooden materials and its emission1.1 Emission of VOC from constructing wood material and transport mechanismComponents and concentration distribution of VOC inside wooden constructing material were measured. Emission rate of VOC from the material surface was measured under various surface temperatures of material. It was found that emission rates increases with temperature and changes with components and constructing materials.2) Generation of particulate materials in an indoor space2.1 Effects of the walking motion on dust re-suspension from floor surfaceThe amount of dust re-suspension from floor by walking was measured for various speed of walking. It was clarified that the amount of re-suspended particles increased with the walking speed and changed with floor and shoes materials.3) Numerical analysis of flow patterns in an indoor space3.1 Fundamental study on the layered ventilation of the semi-closed space with heat and dust generationFlow in an indoor space, where a heat and dust source exists, was visualized and the numerical analysis was conducted to discuss the condition for the layered concentration distribution of dust. It was found that a circulation flow below mid height of the space is effective when the buoyancy flow from heat source is predominant.3.2 Numerical analysis of flow pattern and concentration distributions of gas from a heaterThe numerical analysis of indoor air environment such as air quality, temperature, humidity and flow patterns, was conducted for different types of ventilation. Suction ventilation system was fond to be effective for comfortable temperature distributions and low concentration of pollutants.19994) Development of technologies for improving the indoor environment4.1 Removal of VOCs liberated from Wooden Materials using TiO2 Nano-size Particles on PTFE Sheet Activated by UV IrradiationIt confirmed that VOCs is removed by adsorbing and oxidizing VOCs on TiO_D22_D2 particles surface after irradiating UV at the net-like sheet made from PTFE which using TiO_D22_D2 nano-size particles.4.2 Fundamental study on gaseous hazards removal by TiO_D22_D2 Nano-size aerosolBy UV irradiation, aerosol of TiO_D22_D2 nano-size particles was activated to remove effectively gaseous hazards such as VOC and mercury. It was confirmed that mercury could be oxidized and deposited on TiO_D22_D2 surface, effectively. SiO2 aerosol reduced the removal efficiency because of the completion of water with TiO_D22_D2 required for the activation.<br />研究課題/領域番号:10650537, 研究期間(年度):1998 – 1999<br />出典：「高気密・高断熱空間の居住快適性制御手法の開発」研究成果報告書 課題番号10650537（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-10650585/106505851999kenkyu_seika_hokoku_gaiyo/）を加工して作成
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