We studied on parameters affecting the nucleation and growth of a Y123 single-domained crystal in top seeded melt processing. We developed a new processing, two-step undercooling technique. The keys of this technique are the controlled nucleation of Y123 at the primary undercooling state and the accelerated growth at the secondary undercooling temperature. Optimization of the processing parameters in the two step undercooling technique considerably reduced the processing time required for the growth of the Y123 single crystal without degradation of the levitation property.
We developed a new type of flywheel energy storage system that has a horizontal axle with high To super conductor bearings using the Y123 single-domained crystals. The dynamic properties, stiffness and damping, of the high To superconductor radial bearings applied in the flywheel energy storage system were experimen tally estimated using the imbalance excitation method. The imbalance excitation method applied to this rotor bearing system identified the direct stiffness and damping of the high temperature superconductor bearings to be 2.8-3.3×10⁵ N/m and 175-204N·sec/m, respectively.

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The objective of this research is to develop criteria for improving mixedness by proper selection of the powder components. Our two-pronged approach involves both computation and experimental determination of mixedness. Computation of mixedness utilizes a modular program that incorporates powder components and packs them via dropping and rolling. The virtual mixture is interrogated using concentric shell and tessellation analysis. The experimental determination of mixedness begins with epoxy-embedded microstruc tures. A focused ion beam produces smooth planar cross-sections for mixture analysis of a wide range of materials. Tessellation analysis of high resolution x-ray maps is used to interrogate the mixture, offering us the ability to compute tile area distributions, which allows us to compare the structure of simulated and experimental systems. Having this capability allows us to develop a benchmark for the mixedness possible in a chosen system. In addition, it allows us to develop techniques for improving that benchmark through variation of the powder component characteristics.

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The purpose in this study is to investigate the rational mix design method of water permeable concrete sat isfying environmental and structural requirements such as a proper coefficient of permeability and compres sive strength. Voids in the concrete were classified into the three types of void of permeable, non permeable and entrained air, and the absolute volume of aggregates, and the volume ratio of cement paste to aggregates were defined in this study. Thus, the new mix design method for a water permeable concrete by vibrating compaction was proposed and applied availably for the practical mix proportion. Mechanical properties such as modulus of elasticity, tensile strength and flexural strength of the water permeable concrete were also measured.

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Experimental measurements were made of the tensile strength and the specific gravity of the compressed tablets which were produced with two different types of incinerated sewage sludge. The chemical elements of the sludge were also analyzed with a radiometric analyzer for developing a useful application of them. The effects of additives on the physical properties of the tablets were also confirmed with fly ash, calcium carbonate, and zeolite by using a compression device. The results show that zeolite was superior as a most effective and promising additive for making useful tablets from the incinerated sludge.

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Preparation of various porous ceramics by selective leaching method and their properties were summa rized and reviewed in this paper. Porous ceramics can be prepared utilizing variety of composite microtextures and crystal structures. Using interconnected microtexture in phase separated glasses formed by spinodal decomposition, porous glasses have been prepared and used for filter materials because they have crack free piercing pores in uniform size and good mechanical strength. Porous materials can be also prepared using nanocomposite microtextures formed by phase separation, crystallization and etc. In these porous materials, pores were formed by selective leaching of amorphous matrix. Since very fine nanocrystalline grains were spatially separated and exposed in the surface of pores, various interesting prop erties were obtained. Porous materials with unique porous properties can be prepared by selective leaching method from crystals with characteristic structures such as chain, layered and framework utilizing solubility difference in various components.

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Natural zeolite was used for the infrared ray (IR) radiation bodies and the spectral emissivity was meas ured. IR radiation bodies were tested as a heater, and we examined the heat-retention of human body. As a result, the surface temperature heated by the IR radiation bodies was low, and it seemed that IR radiation is not efficient for rapid heating than other ways. However, after six minutes from the heating stop, it was clear that heating by the IR radiation is the best in heat-retention.

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Eight γ-cyclodextrin (γ-CyD) derivatives having two optically active (R) - or (S) -2- (1-naphthyl) propanoyl residues at the primary hydroxyl sides, which are 6A, 6B-, 6A, 6C-, 6A, 6D-, and 6A, 6Epositions (RR-AB, RR-AC, RR-AD, RR-AE, SS-AB, SS-AC, SS-AD, and SS-AE, respectively), were synthesized for investigating their fluorescence responses towards bile acids in a 10 vol.% ethylene glycol aqueous solutions. Strong intramolecular excimer fluorescence observed for RR-AD, RR-AE, SS-AD, and SS-AE is varied either strengthened or weakened direction based on the guest species. Although RR-AB, RR-AC, SS-AB, and SS-AC showed weak or no excimer fluorescence, some bile acids changed the monomer fluorescence intensity decreased, with excimer fluorescence being induced. By taking the fluorescence intensity changes as a sensitivity factor for detecting the guests, together with the shift in peak positions of the excimer fluorescence, one may qualitatively determine the type of bile acids in a solution at 50mmol dm-3. No simple correlation is observed between the 1: 1 host-guest binding constants and the sensing factors, which indicated that not only the binding strength but also the binding conformation governed the sensitivity and selectivity of the hosts.

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Bis (tricyclo [4.3.0.12, 5] dec-7-ene-3-yl) ether (BTDE), which is suitable starting substance for lubricating oil and a high viscous blending component, has been synthesized from dicyclopentadiene (DCPD) and heteropolyacid as a catalyst. The method made a solution of the problems of a low yield and a production of a lot of wasted sulfuric acid came from a previous preparation of BTDE, in which BTDE was prepared from DCPD and sulfuric acid. When H₃PMo₁₂O₄₀·30H₂O was used as a solid acid catalyst, BTDE was ob tainable in good yield (63% isolated yield), which is two times scale in comparison with that obtained from the previous method. The sequence of an activity of the catalysts used here is as follows, H₃PMo₁₂O₄₀·30H₂O=H₄SiW₁₂O₄₀·30H₂O<H₃PMo₁₂O₄₀·30H₂O<H₉PV₆Mo₆O₄₀·30H₂O<FeCl₃·6H₂O<CH₃C₆H₄SO₃H·H₂O<25%H₂SO₄. Usage of ethers such as 1, 2-dimethoxyethane, 1, 4-dioxane, and methylisobutyl ketone as a solvent, gave a high yield of BTDE. On the other hand, using of methanol, acetonitrile, and water as a reaction solvent resulted that the reaction was not completely proceeding.

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The grinding rate characteristics of hard fine materials was investigated with a laboratory scale jet mill. The variations of product size distributions of synthetic diamond, alumina and quartz sand with the number of passes were described by using a grinding kinetics approach for various values of the grinding air pressure and the feeding rate. As a result, the grinding rate was found to decrease with increase in the hardness of comminuted materials from quartz to alumina and then to increase slightly for synthetic diamond due to its low impact strength. This trend is more pronounced for all materials with higher gas pressure and lower material feed rate. Thus, it is proved experimentally that the grinding characteristics of very hard materials even around 1, μm with the jet mill still fits the rate equation of comminution but the effect of operational conditions becomes low.

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In a previous paper, considering the reflection energy of SH waves from a gradient inhomogeneous layer, we offered a new rationalized layer element for a two-dimensional elastic analysis. We confirmed that the reflectance is exactly estimated using this new elements without any complexities. In this paper, we ex panded this analysis to the case of a layer with an arbitrary distribution of the acoustic impedance. As an example, when the acoustic impedance and the phase velocity vary sinusoidally with the thickness, and the mass density is constant through the layer, the resulting reflectance is in very close agreement with the exact value, and shows rapid convergence properties. Furthermore, it is shown that the existence of the maximum value of the acoustic impedance in the layer gives rise to the total reflection, even if the acoustic impedance values of the reflected and transmitted side of the layer are equal.

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This paper presents the thermophysical and rheological properties of water-base drilling fluids at low temperature range (-5 to 20°C) expected for the fluid temperature of the offshore drilling at the Nankai Trough. These physical properties are fundamental data for the drilling simulator and also design factors for a heat exchanger to cool down the drilling fluids. The measurement systems for the rheological and thermal characteristics, such as thermal conductivity and heat capacity, have been set up. The drilling fluid density were varied from 1100 to 2000 kg/m³ (9.16 to 16.7 ppg) using barite. Especially, the drilling fluids with high salt concentration were mainly focused in present measurements. Then, the experimental equations against the fluids density for the thermal and rheological properties have been presented in order to estimate the parameters used in the simulations. Furthermore, a simplified estimation for heat transfer rate at casing pipe has been carried out using the measurement data to investigate the effect of the property changes in the casing pipe

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The powder flow property of fine resin particles is critical for printing process and therefore elucidation for what it attributes to is essential for controlling the powder flow property in electrophotography. However, the determinant factor of powder flowability hasn't been elucidated yet. In this study, we examined what de termines powder flowability represented as flow function proposed by Jenike. We used spherical polymethyl methacrylate and polystyrene particles with various particle diameters and evaluated their powder flowability through static stress measurements using Peschl shear cell. We examined the critical factor for the powder flowability. As a result, the force between two resin particles is the determinant factor and mainly consisted of the Van der Waals force.

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