Formation Mechanism of Hydrous-Zirconia Particles Produced by Hydrolysis of ZrOCl2 Solutions: II

The primary and secondary particle sizes of monoclinic hydrous-ZrO₂ particles produced by the hydrolysis of various ZrOCl₂ solutions, with and without the addition of NaCl, CaCl₂, or AlCl₃, were measured using X-ray diffraction and transmission electron microscopy in order to clarify the formation mechanisms of primary and secondary particles. The primary particle size of hydrous ZrO₂, under a constant ZrOCl₂ concentration, decreased monotonously with increasing Cl⁻-ion concentration. On the contrary, the secondary particle size increased monotonously with increasing Cl⁻-ion concentration. The present experimental results revealed that the primary and secondary particle sizes of hydrous ZrO₂ are controlled primarily by the concentrations of H⁺ and Cl⁻ ions produced during hydrolysis, and are independent of the type of added metal ions. The formation mechanisms of the primary and secondary particles of hydrous ZrO₂ were determined on the basis of the present experimental results.     

Numerical analysis of coupled transport and reaction phenomena in an anode-supported flat-tube solid oxide fuel cell

Heat and mass transfer with electrochemical reaction in an anode-supported flat-tube solid oxide fuel cell (FT-SOFC) is studied by means of three-dimensional numerical simulation. The distributions of the reaction fields in the anode-supported FT-SOFC are found to be similar to those in the planar SOFC with co-flow arrangement. However, in comparison with the latter, the concentration and activation overpotentials of the former can be reduced by additional reactant diffusion through the porous rib of the fuel channel. Parametric survey reveals that, for a fixed activation overpotential model, the output voltage can be improved by increasing the pore size of anode, while the cross-sectional geometry has smaller effect on the cell performance. Based on the results of three-dimensional simulation, we also develop a simplified numerical model of anode-supported FT-SOFC, which takes into account the concentration gradients in the thick anode of complex cross-sectional geometry. The simplified model can sufficiently predict the output voltage as well as the distributions of temperature and current density with very low computational cost. Thus, it can be used as a powerful tool for surveying wide range of anode-supported FT-SOFC design parameters.     

Mechano-electrochemistry of a passive surface using an in situ micro-indentation test

Depassivation–repassivation of iron surfaces in boric–borate solutions were investigated by using the micro-indentation test. A pair of current peaks due to repair of the passive film following rupture of the film were observed during a series of indenter drives, i.e., loading and unloading of the indenter. The shape of the current peak depended on environmental conditions (conductivity and pH of the solution) and substrate conditions (mechanical processing history, alloyed element) as well as indentation conditions (repetition, maximum depth, and maximum load). Plastic deformation of the surface was accompanied by surface depassivation, while no depassivation occurred during the elastic deformation, indicating that the passive film on iron has a ductile property. The solution conditions did not affect the scale of depassivation but affected the rate of repassivation. Dislocations in the substrate made surface depassivation difficult but enhanced reactivity during the repassivation. The test also revealed that type-312L stainless steel has high corrosion resistance in a concentrated NaCl solution.     

Leak detection in pipe using transient flow and genetic algorithm

An inverse transient method with genetic algorithm (GA) was applied to leak detection in pipeline. Transient flow caused by valve operation was calculated using the characteristics method. The location and discharge of leak were determined so that the difference of the calculated pressure may be minimized from the reference pressure calculated under a given leak condition. Calculations were done for the leak at one and two locations in pipeline. Furthermore, the effect of noise in pressure data was discussed, and the leak locations and leak discharges can be predicted precisely even in the case of noisy data. This paper was presented at the 9^th Asian International Conference on Fluid Machinery (AICFM9), Jeju Korea, October 16–19, 2007.     

Basic information on new regulatory criteria requiring on-site emergency preparedness for accelerator facilities in Japan

For basic information on new regulatory criteria, the dose rate around a thick target bombarded by proton, electron, or carbon beam having incident energy of 10 MeV–50 GeV (per nucleon in case of carbon) was simulated using the PHITS Monte Carlo code. Based on this simulation, the benchmark which is ‘1 Sv/h at 1 m away from the beam line’ assuming 1% beam loss was evaluated, and compared with the criteria in France and Canada. Based on this evaluation, a new regulatory criteria has been established for requiring on-site emergency preparedness for accelerator facilities in Japan, which is required for the ion accelerator beyond the ion beam of 100 MeV/nucleon and 0.5 kW beam power, and the electron accelerator beyond the electron beam of 50 MeV energy and 1 kW beam power.     

Structure and Properties of Endosperm Starch and Water Soluble Polysaccharides from Sugary Mutant of Rice (Oryza sativa L.)

Structure and properties of starch and water soluble polysaccharides (WSP) from sugary (su) endosperm of rice were examined. The su starch contained more amylose and had a somewhat higher ratio of the short chains to the long chains of amylopectin than normal starch. The WSP consisted of short α-1, 4-chains and their average degree of polymerization was 8.6 glucose units. Susceptibility of the su starch to crude Rh. glucoamylase was higher than that of the normal. The initial and final temperatures and heat of gelatinization of the su starch granules were much lower than those of the normal ones.     

Development of a compact high-density microbial hydrogen reactor for portable bio-fuel cell system

The development of a compact high-density microbial reactor for hydrogen production is described with possible implications to use as a portable bio-fuel cell system. To construct the compact bioreactor, mainly, the cell density and immobilization methods were optimized in this paper. The encapsulation of hydrogen producing bacterium, Escherichia coli strain MC13-4, in alginate gel beads provided approximately three-fold increase in hydrogen production in comparison with the free cell suspension. The immobilized cells (cell density; O.D. 100) and 500 mM glucose solution were packed into a 20 mL glass bottle that was connected to the fuel cell. This system has generated electricity of over 20 mW for 20 min.     

Construction of Cellulose Binding Domain Fusion FMN-Dependent NADH-Azoreductase and Glucose 1-Dehydrogenase for the Development of Flow Injection Analysis with Fusion Enzymes Immobilized on Cellulose

The cellulose binding domain (CBD) of cellulosome-integrating protein A from Clostridium thermocellum NBRC 103400 was genetically fused to FMN-dependent NADH-azoreductase (AZR) and glucose 1-dehydrogenase (GDH) from Bacillus subtilis. The fusion enzymes, AZR-CBD and CBD-GDH, were expressed in Escherichia coli Rosetta-gami B (DE3). The enzymes were purified from cell-free extracts, and the specific activity of AZR-CBD was 15.1 U/mg and that of CBD-GDH was 22.6 U/mg. AZR-CBD and CBD-GDH bound strongly to 0.5 % swollen cellulose at approximately 95 and 98 % of the initial protein amounts, respectively. After immobilization onto the swollen cellulose, AZR-CBD and CBD-GDH retained their catalytic activity. Both enzymes bound weakly to 0.5 % microcrystalline cellulose, but the addition of a high concentration of microcrystalline cellulose (10 %) improved the binding rate of both enzymes. A reactor for flow injection analysis was filled with microcrystalline cellulose-immobilized AZR-CBD and CBD-GDH. This flow injection analysis system was successfully applied for the determination of glucose, and a linear calibration curve was observed in the range of approximately 0.16–2.5 mM glucose, with a correlation coefficient, r, of 0.998.     

Calcium isotope separation by band chromatography using 18-crown-6-ether resin

To develop the ⁴⁸Ca enrichment process, a feasibility study on a band chromatography was made using 9 M HCl solution and crown ether resin synthesized in porous silica beads. Prior to the chromatographic experiments, distribution coefficients, Kd, of Ca²⁺ and Sr²⁺ were measured at different concentrations of these ionic species. The frontal boundary of the chromatography was made by a usual manner of the breakthrough mode of calcium feeding, and the rear boundary was made by introducing strontium as a following ion on the basis of the observed Kd values. It was confirmed that the heavy isotope ⁴⁸Ca was depleted in the rear boundary region, while ⁴⁸Ca was enriched in the front boundary region. The values of separation coefficient ε (= α – 1) in three chromatographic operations at different temperatures were observed as 2 × 10^?3 ~ 3 × 10^?3. The separation coefficients observed in the front boundary regions, where ⁴⁸Ca was enriched, agreed with those observed in the rear boundary regions, where ⁴⁰Ca was enriched.     

湖滨房屋 日本山梨

<正>这间房屋是一间单层别墅,坐落于山梨县富士山山脚的海滨地区。该地区面朝美丽的湖泊,是个非常迷人的地方。湖泊在微风和阳光的抚摸下泛起丝丝涟漪。湖泊两旁种植了高大的榉树和日本枫树。在设计房屋时,我们的主旨就是欣赏周围美丽的自然环境。整间房屋30米×6.3米,沿湖而建,因此在每个房间都可以欣赏湖泊的全景。房屋室内采用以白色为主题色的简约设计。没有任何装饰性元素的中性空间面朝美丽的大自然。室内采光十分充足,室